diff --git a/14UlXIZzwE4.txt b/14UlXIZzwE4.txt new file mode 100644 index 0000000000000000000000000000000000000000..9b582d06c85e1980d4a26f754cff81c6ea0357f3 --- /dev/null +++ b/14UlXIZzwE4.txt @@ -0,0 +1,6331 @@ +align:start position:0% + +morning everyone welcome to 609 5i + + align:start position:0% +morning everyone welcome to 609 5i + + + align:start position:0% +morning everyone welcome to 609 5i +thanks for registering for this class + + align:start position:0% +thanks for registering for this class + + + align:start position:0% +thanks for registering for this class +hope you like it + + align:start position:0% +hope you like it + + + align:start position:0% +hope you like it +my name is stringy David us I'm a + + align:start position:0% +my name is stringy David us I'm a + + + align:start position:0% +my name is stringy David us I'm a +professor of computer science at MIT + + align:start position:0% +professor of computer science at MIT + + + align:start position:0% +professor of computer science at MIT +obviously and I've been teaching at MIT + + align:start position:0% +obviously and I've been teaching at MIT + + + align:start position:0% +obviously and I've been teaching at MIT +for 430 years so I've been at it for a + + align:start position:0% +for 430 years so I've been at it for a + + + align:start position:0% +for 430 years so I've been at it for a +while + + align:start position:0% +while + + + align:start position:0% +while +the reason I'm teaching this IP class is + + align:start position:0% +the reason I'm teaching this IP class is + + + align:start position:0% +the reason I'm teaching this IP class is +because I want to try out this this way + + align:start position:0% +because I want to try out this this way + + + align:start position:0% +because I want to try out this this way +of teaching programming that starts with + + align:start position:0% +of teaching programming that starts with + + + align:start position:0% +of teaching programming that starts with +the recreational world of mathematical + + align:start position:0% +the recreational world of mathematical + + + align:start position:0% +the recreational world of mathematical +puzzles algorithmic puzzles and I want + + align:start position:0% +puzzles algorithmic puzzles and I want + + + align:start position:0% +puzzles algorithmic puzzles and I want +to connect it up to to writing programs + + align:start position:0% +to connect it up to to writing programs + + + align:start position:0% +to connect it up to to writing programs +and I have taught this material before + + align:start position:0% +and I have taught this material before + + + align:start position:0% +and I have taught this material before +in six double oh nine that I think some + + align:start position:0% +in six double oh nine that I think some + + + align:start position:0% +in six double oh nine that I think some +of you are registered for but but I + + align:start position:0% +of you are registered for but but I + + + align:start position:0% +of you are registered for but but I +wanted to teach it in a in a more + + align:start position:0% +wanted to teach it in a in a more + + + align:start position:0% +wanted to teach it in a in a more +interactive informal setting and I + + align:start position:0% +interactive informal setting and I + + + align:start position:0% +interactive informal setting and I +should mention that I wrote a book on + + align:start position:0% +should mention that I wrote a book on + + + align:start position:0% +should mention that I wrote a book on +this which is a book that's recommended + + align:start position:0% +this which is a book that's recommended + + + align:start position:0% +this which is a book that's recommended +or not required for six double O nine + + align:start position:0% +or not required for six double O nine + + + align:start position:0% +or not required for six double O nine +and so you might see this in the MIT + + align:start position:0% +and so you might see this in the MIT + + + align:start position:0% +and so you might see this in the MIT +press bookstore and other places and + + align:start position:0% +press bookstore and other places and + + + align:start position:0% +press bookstore and other places and +most of the material I'm gonna cover + + align:start position:0% +most of the material I'm gonna cover + + + align:start position:0% +most of the material I'm gonna cover +here is from the book but I don't want + + align:start position:0% +here is from the book but I don't want + + + align:start position:0% +here is from the book but I don't want +you to read the book because I want you + + align:start position:0% +you to read the book because I want you + + + align:start position:0% +you to read the book because I want you +to listen to my explanations for the + + align:start position:0% +to listen to my explanations for the + + + align:start position:0% +to listen to my explanations for the +puzzles and try and think of the the + + align:start position:0% +puzzles and try and think of the the + + + align:start position:0% +puzzles and try and think of the the +solutions yourself and and then + + align:start position:0% +solutions yourself and and then + + + align:start position:0% +solutions yourself and and then +obviously I do some one decoding a knot + + align:start position:0% +obviously I do some one decoding a knot + + + align:start position:0% +obviously I do some one decoding a knot +during lecture but offline and I'll show + + align:start position:0% +during lecture but offline and I'll show + + + align:start position:0% +during lecture but offline and I'll show +you some solutions to the puzzles and + + align:start position:0% +you some solutions to the puzzles and + + + align:start position:0% +you some solutions to the puzzles and +there'll be some exercises so if I don't + + align:start position:0% +there'll be some exercises so if I don't + + + align:start position:0% +there'll be some exercises so if I don't +want to spend a whole lot of time on + + align:start position:0% +want to spend a whole lot of time on + + + align:start position:0% +want to spend a whole lot of time on +logistics I this is an IEP class as I + + align:start position:0% +logistics I this is an IEP class as I + + + align:start position:0% +logistics I this is an IEP class as I +mentioned I'd like this to be informal + + align:start position:0% +mentioned I'd like this to be informal + + + align:start position:0% +mentioned I'd like this to be informal +and relaxed so we meet every day for two + + align:start position:0% +and relaxed so we meet every day for two + + + align:start position:0% +and relaxed so we meet every day for two +weeks we have the holiday coming up on + + align:start position:0% +weeks we have the holiday coming up on + + + align:start position:0% +weeks we have the holiday coming up on +Monday so we'll have nine total lectures + + align:start position:0% +Monday so we'll have nine total lectures + + + align:start position:0% +Monday so we'll have nine total lectures +roughly for an hour might spill over but + + align:start position:0% +roughly for an hour might spill over but + + + align:start position:0% +roughly for an hour might spill over but +hopefully you'll you'll be okay with it + + align:start position:0% +hopefully you'll you'll be okay with it + + + align:start position:0% +hopefully you'll you'll be okay with it +because you don't have you know another + + align:start position:0% +because you don't have you know another + + + align:start position:0% +because you don't have you know another +class to go to at noon and if you do + + align:start position:0% +class to go to at noon and if you do + + + align:start position:0% +class to go to at noon and if you do +yeah well let me know and I'll give you + + align:start position:0% +yeah well let me know and I'll give you + + + align:start position:0% +yeah well let me know and I'll give you +that five minutes of + + align:start position:0% +that five minutes of + + + align:start position:0% +that five minutes of +overflow personally at some at a time of + + align:start position:0% +overflow personally at some at a time of + + + align:start position:0% +overflow personally at some at a time of +your choosing but hopefully I'll keep + + align:start position:0% +your choosing but hopefully I'll keep + + + align:start position:0% +your choosing but hopefully I'll keep +keep on time so I and in terms of work I + + align:start position:0% +keep on time so I and in terms of work I + + + align:start position:0% +keep on time so I and in terms of work I +mean this is a pass/fail it's it's a + + align:start position:0% +mean this is a pass/fail it's it's a + + + align:start position:0% +mean this is a pass/fail it's it's a +four credit class I know some of you may + + align:start position:0% +four credit class I know some of you may + + + align:start position:0% +four credit class I know some of you may +be listeners but some of you are + + align:start position:0% +be listeners but some of you are + + + align:start position:0% +be listeners but some of you are +registered for it so I'll have to assign + + align:start position:0% +registered for it so I'll have to assign + + + align:start position:0% +registered for it so I'll have to assign +you a grade so there will be some + + align:start position:0% +you a grade so there will be some + + + align:start position:0% +you a grade so there will be some +exercises and I'm gonna make it very + + align:start position:0% +exercises and I'm gonna make it very + + + align:start position:0% +exercises and I'm gonna make it very +simple you little that the exercise is + + align:start position:0% +simple you little that the exercise is + + + align:start position:0% +simple you little that the exercise is +up on the website + + align:start position:0% +up on the website + + + align:start position:0% +up on the website +there'll be do you know two days from + + align:start position:0% +there'll be do you know two days from + + + align:start position:0% +there'll be do you know two days from +when I put them up and you'll have + + align:start position:0% +when I put them up and you'll have + + + align:start position:0% +when I put them up and you'll have +options in terms of whether to do a + + align:start position:0% +options in terms of whether to do a + + + align:start position:0% +options in terms of whether to do a +really simple exercise that's you know + + align:start position:0% +really simple exercise that's you know + + + align:start position:0% +really simple exercise that's you know +probably going to take about a five + + align:start position:0% +probably going to take about a five + + + align:start position:0% +probably going to take about a five +minutes or do something harder right and + + align:start position:0% +minutes or do something harder right and + + + align:start position:0% +minutes or do something harder right and +for each of the puzzles there's a two or + + align:start position:0% +for each of the puzzles there's a two or + + + align:start position:0% +for each of the puzzles there's a two or +three exercises and you get to do all of + + align:start position:0% +three exercises and you get to do all of + + + align:start position:0% +three exercises and you get to do all of +them if you want you can choose to do + + align:start position:0% +them if you want you can choose to do + + + align:start position:0% +them if you want you can choose to do +one or the other + + align:start position:0% +one or the other + + + align:start position:0% +one or the other +alright I'm gonna have office hours + + align:start position:0% +alright I'm gonna have office hours + + + align:start position:0% +alright I'm gonna have office hours +every day from one to two I don't plan + + align:start position:0% +every day from one to two I don't plan + + + align:start position:0% +every day from one to two I don't plan +on putting solutions up to the exercises + + align:start position:0% +on putting solutions up to the exercises + + + align:start position:0% +on putting solutions up to the exercises +the solutions to the to the puzzles + + align:start position:0% +the solutions to the to the puzzles + + + align:start position:0% +the solutions to the to the puzzles +themselves they'll be shown mostly in + + align:start position:0% +themselves they'll be shown mostly in + + + align:start position:0% +themselves they'll be shown mostly in +lecture and and put up on the seller + + align:start position:0% +lecture and and put up on the seller + + + align:start position:0% +lecture and and put up on the seller +website but the solutions to the + + align:start position:0% +website but the solutions to the + + + align:start position:0% +website but the solutions to the +exercises I'm not gonna put up but if + + align:start position:0% +exercises I'm not gonna put up but if + + + align:start position:0% +exercises I'm not gonna put up but if +you ever get stuck well that's what + + align:start position:0% +you ever get stuck well that's what + + + align:start position:0% +you ever get stuck well that's what +office hours are for and if you can't + + align:start position:0% +office hours are for and if you can't + + + align:start position:0% +office hours are for and if you can't +solve the exercises I'll help you solve + + align:start position:0% +solve the exercises I'll help you solve + + + align:start position:0% +solve the exercises I'll help you solve +them alright so did that without further + + align:start position:0% +them alright so did that without further + + + align:start position:0% +them alright so did that without further +ado let's let's dive in and talk about + + align:start position:0% +ado let's let's dive in and talk about + + + align:start position:0% +ado let's let's dive in and talk about +talk about puzzles and solving puzzles + + align:start position:0% +talk about puzzles and solving puzzles + + + align:start position:0% +talk about puzzles and solving puzzles +using algorithms and then and then + + align:start position:0% +using algorithms and then and then + + + align:start position:0% +using algorithms and then and then +programs I'd really like this to be + + align:start position:0% +programs I'd really like this to be + + + align:start position:0% +programs I'd really like this to be +interactive so the police ask questions + + align:start position:0% +interactive so the police ask questions + + + align:start position:0% +interactive so the police ask questions +and suggest solutions that I haven't + + align:start position:0% +and suggest solutions that I haven't + + + align:start position:0% +and suggest solutions that I haven't +taught off you know that'd be great in + + align:start position:0% +taught off you know that'd be great in + + + align:start position:0% +taught off you know that'd be great in +my second edition you know whenever that + + align:start position:0% +my second edition you know whenever that + + + align:start position:0% +my second edition you know whenever that +is you'll get credit for that alright so + + align:start position:0% +is you'll get credit for that alright so + + + align:start position:0% +is you'll get credit for that alright so +the first puzzle I I tried to have I + + align:start position:0% +the first puzzle I I tried to have I + + + align:start position:0% +the first puzzle I I tried to have I +don't know funny + + align:start position:0% +don't know funny + + + align:start position:0% +don't know funny +titles for all of these puzzles + + align:start position:0% +titles for all of these puzzles + + + align:start position:0% +titles for all of these puzzles +intriguing and so the first puzzle is + + align:start position:0% +intriguing and so the first puzzle is + + + align:start position:0% +intriguing and so the first puzzle is +called you will all confirm it this is + + align:start position:0% +called you will all confirm it this is + + + align:start position:0% +called you will all confirm it this is +really a warm-up puzzle as you'll see I + + align:start position:0% +really a warm-up puzzle as you'll see I + + + align:start position:0% +really a warm-up puzzle as you'll see I +mean this is true for any class things + + align:start position:0% +mean this is true for any class things + + + align:start position:0% +mean this is true for any class things +are going to get more complicated as we + + align:start position:0% +are going to get more complicated as we + + + align:start position:0% +are going to get more complicated as we +go along so if you'll probably do ten or + + align:start position:0% +go along so if you'll probably do ten or + + + align:start position:0% +go along so if you'll probably do ten or +twelve puzzles in the next two weeks + + align:start position:0% +twelve puzzles in the next two weeks + + + align:start position:0% +twelve puzzles in the next two weeks +and by the end you're going to see + + align:start position:0% +and by the end you're going to see + + + align:start position:0% +and by the end you're going to see +things like memorization and dynamic + + align:start position:0% +things like memorization and dynamic + + + align:start position:0% +things like memorization and dynamic +programming and things like that but + + align:start position:0% +programming and things like that but + + + align:start position:0% +programming and things like that but +towards the end of next week and if you + + align:start position:0% +towards the end of next week and if you + + + align:start position:0% +towards the end of next week and if you +don't know what those mean well that's + + align:start position:0% +don't know what those mean well that's + + + align:start position:0% +don't know what those mean well that's +great because you're hopefully you know + + align:start position:0% +great because you're hopefully you know + + + align:start position:0% +great because you're hopefully you know +you will know by the by the end of the + + align:start position:0% +you will know by the by the end of the + + + align:start position:0% +you will know by the by the end of the +two weeks and a lot of these things are + + align:start position:0% +two weeks and a lot of these things are + + + align:start position:0% +two weeks and a lot of these things are +algorithmic insights are insights that + + align:start position:0% +algorithmic insights are insights that + + + align:start position:0% +algorithmic insights are insights that +will help you in course six classes for + + align:start position:0% +will help you in course six classes for + + + align:start position:0% +will help you in course six classes for +sure and you know perhaps even if you + + align:start position:0% +sure and you know perhaps even if you + + + align:start position:0% +sure and you know perhaps even if you +follow a career outside of outside of + + align:start position:0% +follow a career outside of outside of + + + align:start position:0% +follow a career outside of outside of +course six all right so this particular + + align:start position:0% +course six all right so this particular + + + align:start position:0% +course six all right so this particular +puzzle is as I said a fairly simple + + align:start position:0% +puzzle is as I said a fairly simple + + + align:start position:0% +puzzle is as I said a fairly simple +puzzle at least to describe and the + + align:start position:0% +puzzle at least to describe and the + + + align:start position:0% +puzzle at least to describe and the +setting is as follows so you're a + + align:start position:0% +setting is as follows so you're a + + + align:start position:0% +setting is as follows so you're a +gatekeeper at a baseball game we'll just + + align:start position:0% +gatekeeper at a baseball game we'll just + + + align:start position:0% +gatekeeper at a baseball game we'll just +call it a baseball game because baseball + + align:start position:0% +call it a baseball game because baseball + + + align:start position:0% +call it a baseball game because baseball +players wear caps and you know that's + + align:start position:0% +players wear caps and you know that's + + + align:start position:0% +players wear caps and you know that's +most people are watching games with caps + + align:start position:0% +most people are watching games with caps + + + align:start position:0% +most people are watching games with caps +on and so you're a gate keeper and + + align:start position:0% +on and so you're a gate keeper and + + + align:start position:0% +on and so you're a gate keeper and +there's a bunch of people standing in + + align:start position:0% +there's a bunch of people standing in + + + align:start position:0% +there's a bunch of people standing in +line let's just say each of them knows + + align:start position:0% +line let's just say each of them knows + + + align:start position:0% +line let's just say each of them knows +their number and this is Python so the + + align:start position:0% +their number and this is Python so the + + + align:start position:0% +their number and this is Python so the +number starts at zero okay as opposed to + + align:start position:0% +number starts at zero okay as opposed to + + + align:start position:0% +number starts at zero okay as opposed to +one and there's there's a whole bunch of + + align:start position:0% +one and there's there's a whole bunch of + + + align:start position:0% +one and there's there's a whole bunch of +people standing in line ready to get in + + align:start position:0% +people standing in line ready to get in + + + align:start position:0% +people standing in line ready to get in +and they they all have caps and some of + + align:start position:0% +and they they all have caps and some of + + + align:start position:0% +and they they all have caps and some of +them you know wearing their caps for + + align:start position:0% +them you know wearing their caps for + + + align:start position:0% +them you know wearing their caps for +words so with the with the I guess what + + align:start position:0% +words so with the with the I guess what + + + align:start position:0% +words so with the with the I guess what +do you call it what's the front of the + + align:start position:0% +do you call it what's the front of the + + + align:start position:0% +do you call it what's the front of the +cap called the shape the the thing that + + align:start position:0% +cap called the shape the the thing that + + + align:start position:0% +cap called the shape the the thing that +gives you shape you know up front and so + + align:start position:0% +gives you shape you know up front and so + + + align:start position:0% +gives you shape you know up front and so +we just we just say let me try and draw + + align:start position:0% +we just we just say let me try and draw + + + align:start position:0% +we just we just say let me try and draw +this out so said this person is wearing + + align:start position:0% +this out so said this person is wearing + + + align:start position:0% +this out so said this person is wearing +his cap like that and and this lady here + + align:start position:0% +his cap like that and and this lady here + + + align:start position:0% +his cap like that and and this lady here +is is wearing her cap like this + + align:start position:0% +is is wearing her cap like this + + + align:start position:0% +is is wearing her cap like this +alright so that's four words and that's + + align:start position:0% +alright so that's four words and that's + + + align:start position:0% +alright so that's four words and that's +backwards okay so you're your job here + + align:start position:0% +backwards okay so you're your job here + + + align:start position:0% +backwards okay so you're your job here +is straight forward you can only let all + + align:start position:0% +is straight forward you can only let all + + + align:start position:0% +is straight forward you can only let all +of these people in into line in sorry + + align:start position:0% +of these people in into line in sorry + + + align:start position:0% +of these people in into line in sorry +into the stadium that were in line if + + align:start position:0% +into the stadium that were in line if + + + align:start position:0% +into the stadium that were in line if +they all + + align:start position:0% +they all + + + align:start position:0% +they all +conform okay so so they all have to wear + + align:start position:0% +conform okay so so they all have to wear + + + align:start position:0% +conform okay so so they all have to wear +their caps in a particular orientation + + align:start position:0% +their caps in a particular orientation + + + align:start position:0% +their caps in a particular orientation +and you don't particularly care which + + align:start position:0% +and you don't particularly care which + + + align:start position:0% +and you don't particularly care which +one all right + + align:start position:0% +one all right + + + align:start position:0% +one all right +and so they all have to be forwards you + + align:start position:0% +and so they all have to be forwards you + + + align:start position:0% +and so they all have to be forwards you +know all let's say you know 13 of them + + align:start position:0% +know all let's say you know 13 of them + + + align:start position:0% +know all let's say you know 13 of them +are they all have to be backwards right + + align:start position:0% +are they all have to be backwards right + + + align:start position:0% +are they all have to be backwards right +now all of them know their position on + + align:start position:0% +now all of them know their position on + + + align:start position:0% +now all of them know their position on +the line all right so this person knows + + align:start position:0% +the line all right so this person knows + + + align:start position:0% +the line all right so this person knows +that his position is zero this lady here + + align:start position:0% +that his position is zero this lady here + + + align:start position:0% +that his position is zero this lady here +knows that her position is one etc etc + + align:start position:0% +knows that her position is one etc etc + + + align:start position:0% +knows that her position is one etc etc +right and so so obviously you'd like to + + align:start position:0% +right and so so obviously you'd like to + + + align:start position:0% +right and so so obviously you'd like to +minimize the amount of work that you do + + align:start position:0% +minimize the amount of work that you do + + + align:start position:0% +minimize the amount of work that you do +and you could certainly choose let's say + + align:start position:0% +and you could certainly choose let's say + + + align:start position:0% +and you could certainly choose let's say +you want everyone to be forwards you + + align:start position:0% +you want everyone to be forwards you + + + align:start position:0% +you want everyone to be forwards you +could say hey lady in position one flip + + align:start position:0% +could say hey lady in position one flip + + + align:start position:0% +could say hey lady in position one flip +your cap right oh I should mention + + align:start position:0% +your cap right oh I should mention + + + align:start position:0% +your cap right oh I should mention +something that is important so people + + align:start position:0% +something that is important so people + + + align:start position:0% +something that is important so people +have a different definition of forwards + + align:start position:0% +have a different definition of forwards + + + align:start position:0% +have a different definition of forwards +and backwards you know that it's it's + + align:start position:0% +and backwards you know that it's it's + + + align:start position:0% +and backwards you know that it's it's +sort of what's natural and what's + + align:start position:0% +sort of what's natural and what's + + + align:start position:0% +sort of what's natural and what's +unnatural to them so so it's we think + + align:start position:0% +unnatural to them so so it's we think + + + align:start position:0% +unnatural to them so so it's we think +that this person has his cap on forwards + + align:start position:0% +that this person has his cap on forwards + + + align:start position:0% +that this person has his cap on forwards +you know before all you know he thinks + + align:start position:0% +you know before all you know he thinks + + + align:start position:0% +you know before all you know he thinks +he's got his cap on backwards or + + align:start position:0% +he's got his cap on backwards or + + + align:start position:0% +he's got his cap on backwards or +vice-versa + + align:start position:0% +vice-versa + + + align:start position:0% +vice-versa +right so you can it assume that the + + align:start position:0% +right so you can it assume that the + + + align:start position:0% +right so you can it assume that the +definition of forwards and backwards is + + align:start position:0% +definition of forwards and backwards is + + + align:start position:0% +definition of forwards and backwards is +identical for all of the people in line + + align:start position:0% +identical for all of the people in line + + + align:start position:0% +identical for all of the people in line +and and and really is the same as your + + align:start position:0% +and and and really is the same as your + + + align:start position:0% +and and and really is the same as your +definition I mean if it seems kind of + + align:start position:0% +definition I mean if it seems kind of + + + align:start position:0% +definition I mean if it seems kind of +unreasonable hey I mean this is a puzzle + + align:start position:0% +unreasonable hey I mean this is a puzzle + + + align:start position:0% +unreasonable hey I mean this is a puzzle +ok so so so let's let's let's not argue + + align:start position:0% +ok so so so let's let's let's not argue + + + align:start position:0% +ok so so so let's let's let's not argue +about that we can argue about other + + align:start position:0% +about that we can argue about other + + + align:start position:0% +about that we can argue about other +things like how to write Python programs + + align:start position:0% +things like how to write Python programs + + + align:start position:0% +things like how to write Python programs +properly so so what you have to do now + + align:start position:0% +properly so so what you have to do now + + + align:start position:0% +properly so so what you have to do now +is you have to call out commands that + + align:start position:0% +is you have to call out commands that + + + align:start position:0% +is you have to call out commands that +correspond to saying person in position + + align:start position:0% +correspond to saying person in position + + + align:start position:0% +correspond to saying person in position +zero + + align:start position:0% +zero + + + align:start position:0% +zero +flip your cap right that's all you can + + align:start position:0% +flip your cap right that's all you can + + + align:start position:0% +flip your cap right that's all you can +say you can just say flip your cap right + + align:start position:0% +say you can just say flip your cap right + + + align:start position:0% +say you can just say flip your cap right +and you can obviously see how these caps + + align:start position:0% +and you can obviously see how these caps + + + align:start position:0% +and you can obviously see how these caps +are oriented and you can ask let's say + + align:start position:0% +are oriented and you can ask let's say + + + align:start position:0% +are oriented and you can ask let's say +that you had something like that I'm + + align:start position:0% +that you had something like that I'm + + + align:start position:0% +that you had something like that I'm +just making this up as I go along in + + align:start position:0% +just making this up as I go along in + + + align:start position:0% +just making this up as I go along in +terms of I'm not going to draw all the + + align:start position:0% +terms of I'm not going to draw all the + + + align:start position:0% +terms of I'm not going to draw all the +caps here but this is what it looks like + + align:start position:0% +caps here but this is what it looks like + + + align:start position:0% +caps here but this is what it looks like +and so you see in according to you you + + align:start position:0% +and so you see in according to you you + + + align:start position:0% +and so you see in according to you you +know UCF the + + align:start position:0% +know UCF the + + + align:start position:0% +know UCF the +be in terms of forwards and backwards + + align:start position:0% +be in terms of forwards and backwards + + + align:start position:0% +be in terms of forwards and backwards +and let's say you decide that you want + + align:start position:0% +and let's say you decide that you want + + + align:start position:0% +and let's say you decide that you want +everyone to have their their cap on + + align:start position:0% +everyone to have their their cap on + + + align:start position:0% +everyone to have their their cap on +forwards then you would you could say a + + align:start position:0% +forwards then you would you could say a + + + align:start position:0% +forwards then you would you could say a +person in position one flip your cap + + align:start position:0% +person in position one flip your cap + + + align:start position:0% +person in position one flip your cap +with person in position to flip your cap + + align:start position:0% +with person in position to flip your cap + + + align:start position:0% +with person in position to flip your cap +and then person whose position for 7 etc + + align:start position:0% +and then person whose position for 7 etc + + + align:start position:0% +and then person whose position for 7 etc +right and you want to make it easier on + + align:start position:0% +right and you want to make it easier on + + + align:start position:0% +right and you want to make it easier on +yourself because people do know their + + align:start position:0% +yourself because people do know their + + + align:start position:0% +yourself because people do know their +indices their positions in line and so + + align:start position:0% +indices their positions in line and so + + + align:start position:0% +indices their positions in line and so +you can say to save yourself some + + align:start position:0% +you can say to save yourself some + + + align:start position:0% +you can say to save yourself some +trouble you could say people in + + align:start position:0% +trouble you could say people in + + + align:start position:0% +trouble you could say people in +positions 1 through 2 and the + + align:start position:0% +positions 1 through 2 and the + + + align:start position:0% +positions 1 through 2 and the +implication is that it's inclusive flip + + align:start position:0% +implication is that it's inclusive flip + + + align:start position:0% +implication is that it's inclusive flip +your caps right and so that takes care + + align:start position:0% +your caps right and so that takes care + + + align:start position:0% +your caps right and so that takes care +of these two and perhaps you know eight + + align:start position:0% +of these two and perhaps you know eight + + + align:start position:0% +of these two and perhaps you know eight +here and nine you know had their caps on + + align:start position:0% + + + + align:start position:0% + +backwards and you could say are people + + align:start position:0% +backwards and you could say are people + + + align:start position:0% +backwards and you could say are people +in positions seven through nine flip + + align:start position:0% +in positions seven through nine flip + + + align:start position:0% +in positions seven through nine flip +your caps right so in this particular + + align:start position:0% +your caps right so in this particular + + + align:start position:0% +your caps right so in this particular +example assuming that things ended with + + align:start position:0% +example assuming that things ended with + + + align:start position:0% +example assuming that things ended with +ten people in line zero through nine you + + align:start position:0% +ten people in line zero through nine you + + + align:start position:0% +ten people in line zero through nine you +could get away with three commands you + + align:start position:0% +could get away with three commands you + + + align:start position:0% +could get away with three commands you +could say one through two and the + + align:start position:0% +could say one through two and the + + + align:start position:0% +could say one through two and the +implication as I said this this is + + align:start position:0% +implication as I said this this is + + + align:start position:0% +implication as I said this this is +inclusive flip and then you could say + + align:start position:0% +inclusive flip and then you could say + + + align:start position:0% +inclusive flip and then you could say +four flip and then you could say is + + align:start position:0% +four flip and then you could say is + + + align:start position:0% +four flip and then you could say is +seven through nine flip okay and if you + + align:start position:0% +seven through nine flip okay and if you + + + align:start position:0% +seven through nine flip okay and if you +did it the other way you could also say + + align:start position:0% +did it the other way you could also say + + + align:start position:0% +did it the other way you could also say +person that 0 flip and so this would go + + align:start position:0% +person that 0 flip and so this would go + + + align:start position:0% +person that 0 flip and so this would go +backwards person eight three flip + + align:start position:0% +backwards person eight three flip + + + align:start position:0% +backwards person eight three flip +obviously you can't say zero through + + align:start position:0% +obviously you can't say zero through + + + align:start position:0% +obviously you can't say zero through +three because that would be wrong and + + align:start position:0% +three because that would be wrong and + + + align:start position:0% +three because that would be wrong and +and then you could you could say five + + align:start position:0% +and then you could you could say five + + + align:start position:0% +and then you could you could say five +through five through six year so you + + align:start position:0% +through five through six year so you + + + align:start position:0% +through five through six year so you +would get three three commands in that + + align:start position:0% +would get three three commands in that + + + align:start position:0% +would get three three commands in that +case as well but if in fact for + + align:start position:0% +case as well but if in fact for + + + align:start position:0% +case as well but if in fact for +argument's sake let's just say that I'm + + align:start position:0% +argument's sake let's just say that I'm + + + align:start position:0% +argument's sake let's just say that I'm +gonna just turn this into ten and put it + + align:start position:0% +gonna just turn this into ten and put it + + + align:start position:0% +gonna just turn this into ten and put it +put an F down here then + + align:start position:0% +put an F down here then + + + align:start position:0% +put an F down here then +these three commands would still work if + + align:start position:0% +these three commands would still work if + + + align:start position:0% +these three commands would still work if +you wanted to focus on the on the bees + + align:start position:0% +you wanted to focus on the on the bees + + + align:start position:0% +you wanted to focus on the on the bees +on the backwards people and make make + + align:start position:0% +on the backwards people and make make + + + align:start position:0% +on the backwards people and make make +them go forwards but if you wanted to + + align:start position:0% +them go forwards but if you wanted to + + + align:start position:0% +them go forwards but if you wanted to +make all of the forward people go + + align:start position:0% +make all of the forward people go + + + align:start position:0% +make all of the forward people go +backwards you would need one two three + + align:start position:0% +backwards you would need one two three + + + align:start position:0% +backwards you would need one two three +four four commands alright so so in this + + align:start position:0% +four four commands alright so so in this + + + align:start position:0% +four four commands alright so so in this +particular case you're better off doing + + align:start position:0% +particular case you're better off doing + + + align:start position:0% +particular case you're better off doing +that as opposed to doing four commands + + align:start position:0% +that as opposed to doing four commands + + + align:start position:0% +that as opposed to doing four commands +alright so first straightforward + + align:start position:0% +alright so first straightforward + + + align:start position:0% +alright so first straightforward +question is manat talking about code yet + + align:start position:0% +question is manat talking about code yet + + + align:start position:0% +question is manat talking about code yet +I'm algorithmically you know just in + + align:start position:0% +I'm algorithmically you know just in + + + align:start position:0% +I'm algorithmically you know just in +terms of pseudocode and I'm happy with + + align:start position:0% +terms of pseudocode and I'm happy with + + + align:start position:0% +terms of pseudocode and I'm happy with +English how would you determine the + + align:start position:0% +English how would you determine the + + + align:start position:0% +English how would you determine the +minimum set of commands given a + + align:start position:0% +minimum set of commands given a + + + align:start position:0% +minimum set of commands given a +particular set of people there's an + + align:start position:0% +particular set of people there's an + + + align:start position:0% +particular set of people there's an +arbitrary set of people you want to make + + align:start position:0% +arbitrary set of people you want to make + + + align:start position:0% +arbitrary set of people you want to make +sure that you have the absolute minimum + + align:start position:0% +sure that you have the absolute minimum + + + align:start position:0% +sure that you have the absolute minimum +set of commands and you're going to have + + align:start position:0% +set of commands and you're going to have + + + align:start position:0% +set of commands and you're going to have +to use these intervals so you definitely + + align:start position:0% +to use these intervals so you definitely + + + align:start position:0% +to use these intervals so you definitely +want to look for all the contiguous + + align:start position:0% +want to look for all the contiguous + + + align:start position:0% +want to look for all the contiguous +intervals because obviously if you say + + align:start position:0% +intervals because obviously if you say + + + align:start position:0% +intervals because obviously if you say +one followed and and and then that's a + + align:start position:0% +one followed and and and then that's a + + + align:start position:0% +one followed and and and then that's a +separate command and you say two and + + align:start position:0% +separate command and you say two and + + + align:start position:0% +separate command and you say two and +that's a separate command you end up + + align:start position:0% +that's a separate command you end up + + + align:start position:0% +that's a separate command you end up +having more commands than necessary + + align:start position:0% +having more commands than necessary + + + align:start position:0% +having more commands than necessary +right so so anyone want to tell me I I + + align:start position:0% +right so so anyone want to tell me I I + + + align:start position:0% +right so so anyone want to tell me I I +guess roughly in in terms of pseudocode + + align:start position:0% +guess roughly in in terms of pseudocode + + + align:start position:0% +guess roughly in in terms of pseudocode +how this would work yeah go ahead + + align:start position:0% + + + + align:start position:0% + +yeah + + align:start position:0% + + + + align:start position:0% + +through them and then whatever the + + align:start position:0% +through them and then whatever the + + + align:start position:0% +through them and then whatever the +second one so if you have whatever the + + align:start position:0% +second one so if you have whatever the + + + align:start position:0% +second one so if you have whatever the +second group is if it's ever beat those + + align:start position:0% +second group is if it's ever beat those + + + align:start position:0% +second group is if it's ever beat those +are the ones that + + align:start position:0% + + + + align:start position:0% + +from what you pass through + + align:start position:0% +from what you pass through + + + align:start position:0% +from what you pass through +whatever you just tell them sounds good + + align:start position:0% +whatever you just tell them sounds good + + + align:start position:0% +whatever you just tell them sounds good +do you have anything to add to that + + align:start position:0% + + + + align:start position:0% + +that's good good excellent so both of + + align:start position:0% +that's good good excellent so both of + + + align:start position:0% +that's good good excellent so both of +you had it right so let me explain what + + align:start position:0% +you had it right so let me explain what + + + align:start position:0% +you had it right so let me explain what +these two gentleman what was your name + + align:start position:0% +these two gentleman what was your name + + + align:start position:0% +these two gentleman what was your name +you're not sure what yours fatty + + align:start position:0% +you're not sure what yours fatty + + + align:start position:0% +you're not sure what yours fatty +so Canara and fatty said so so basically + + align:start position:0% +so Canara and fatty said so so basically + + + align:start position:0% +so Canara and fatty said so so basically +this is as I said the natural algorithm + + align:start position:0% +this is as I said the natural algorithm + + + align:start position:0% +this is as I said the natural algorithm +that you would use the natural algorithm + + align:start position:0% +that you would use the natural algorithm + + + align:start position:0% +that you would use the natural algorithm +would be that you walk through this list + + align:start position:0% +would be that you walk through this list + + + align:start position:0% +would be that you walk through this list +and you start computing what I would + + align:start position:0% +and you start computing what I would + + + align:start position:0% +and you start computing what I would +call you call it group Skinner but I'd + + align:start position:0% +call you call it group Skinner but I'd + + + align:start position:0% +call you call it group Skinner but I'd +call them intervals right and an + + align:start position:0% +call them intervals right and an + + + align:start position:0% +call them intervals right and an +interval this is something that is + + align:start position:0% +interval this is something that is + + + align:start position:0% +interval this is something that is +unbroken + + align:start position:0% +unbroken + + + align:start position:0% +unbroken +it's a contiguous it's a contiguous set + + align:start position:0% +it's a contiguous it's a contiguous set + + + align:start position:0% +it's a contiguous it's a contiguous set +of people who all have their caps in the + + align:start position:0% +of people who all have their caps in the + + + align:start position:0% +of people who all have their caps in the +same orientation you know be it forward + + align:start position:0% +same orientation you know be it forward + + + align:start position:0% +same orientation you know be it forward +or backwards and what you would do in + + align:start position:0% +or backwards and what you would do in + + + align:start position:0% +or backwards and what you would do in +this case is you would you would compute + + align:start position:0% +this case is you would you would compute + + + align:start position:0% +this case is you would you would compute +the you'd say I want to look at the + + align:start position:0% +the you'd say I want to look at the + + + align:start position:0% +the you'd say I want to look at the +forward intervals and the forward + + align:start position:0% +forward intervals and the forward + + + align:start position:0% +forward intervals and the forward +intervals would be zero zero because + + align:start position:0% +intervals would be zero zero because + + + align:start position:0% +intervals would be zero zero because +that would essentially what you have in + + align:start position:0% +that would essentially what you have in + + + align:start position:0% +that would essentially what you have in +here and going through that list you + + align:start position:0% +here and going through that list you + + + align:start position:0% +here and going through that list you +would get you would also say I'm gonna + + align:start position:0% +would get you would also say I'm gonna + + + align:start position:0% +would get you would also say I'm gonna +be computing the backward intervals and + + align:start position:0% +be computing the backward intervals and + + + align:start position:0% +be computing the backward intervals and +in this case you discover one two as the + + align:start position:0% +in this case you discover one two as the + + + align:start position:0% +in this case you discover one two as the +backward backwards interval so I'm gonna + + align:start position:0% +backward backwards interval so I'm gonna + + + align:start position:0% +backward backwards interval so I'm gonna +write them out like that and in general + + align:start position:0% +write them out like that and in general + + + align:start position:0% +write them out like that and in general +in the mathematical notation when you + + align:start position:0% +in the mathematical notation when you + + + align:start position:0% +in the mathematical notation when you +put square brackets these are closed + + align:start position:0% +put square brackets these are closed + + + align:start position:0% +put square brackets these are closed +intervals right so so zero is included + + align:start position:0% +intervals right so so zero is included + + + align:start position:0% +intervals right so so zero is included +and we're going to see a puzzle where + + align:start position:0% +and we're going to see a puzzle where + + + align:start position:0% +and we're going to see a puzzle where +you might see something a little bit + + align:start position:0% +you might see something a little bit + + + align:start position:0% +you might see something a little bit +different so I wanted to point that out + + align:start position:0% +different so I wanted to point that out + + + align:start position:0% +different so I wanted to point that out +so one two are both inside this interval + + align:start position:0% +so one two are both inside this interval + + + align:start position:0% +so one two are both inside this interval +and these two you would generate as you + + align:start position:0% +and these two you would generate as you + + + align:start position:0% +and these two you would generate as you +would you would go through the list and + + align:start position:0% +would you would go through the list and + + + align:start position:0% +would you would go through the list and +then you would generate three three over + + align:start position:0% +then you would generate three three over + + + align:start position:0% +then you would generate three three over +here and then you would generate four + + align:start position:0% +here and then you would generate four + + + align:start position:0% +here and then you would generate four +yep that's right just for up I'm sorry + + align:start position:0% +yep that's right just for up I'm sorry + + + align:start position:0% +yep that's right just for up I'm sorry +for four over here if you want to call + + align:start position:0% +for four over here if you want to call + + + align:start position:0% +for four over here if you want to call +it in an interval you could represent + + align:start position:0% +it in an interval you could represent + + + align:start position:0% +it in an interval you could represent +this differently and there's nothing + + align:start position:0% +this differently and there's nothing + + + align:start position:0% +this differently and there's nothing +that's stopping you in Python to have + + align:start position:0% +that's stopping you in Python to have + + + align:start position:0% +that's stopping you in Python to have +these it's slightly more complicated + + align:start position:0% +these it's slightly more complicated + + + align:start position:0% +these it's slightly more complicated +representation where you just have zero + + align:start position:0% +representation where you just have zero + + + align:start position:0% +representation where you just have zero +here as a number and if it's just a + + align:start position:0% +here as a number and if it's just a + + + align:start position:0% +here as a number and if it's just a +number then it represents an interval of + + align:start position:0% +number then it represents an interval of + + + align:start position:0% +number then it represents an interval of +length one but let's just be uniform + + align:start position:0% +length one but let's just be uniform + + + align:start position:0% +length one but let's just be uniform +about this you + + align:start position:0% +about this you + + + align:start position:0% +about this you +usually when you have special cases and + + align:start position:0% +usually when you have special cases and + + + align:start position:0% +usually when you have special cases and +if you do things heterogeneous Lee then + + align:start position:0% +if you do things heterogeneous Lee then + + + align:start position:0% +if you do things heterogeneous Lee then +you have more code to write right it + + align:start position:0% +you have more code to write right it + + + align:start position:0% +you have more code to write right it +might get more efficient but there's + + align:start position:0% +might get more efficient but there's + + + align:start position:0% +might get more efficient but there's +usually more more code to write so you + + align:start position:0% +usually more more code to write so you + + + align:start position:0% +usually more more code to write so you +do for four here and then you'd go up + + align:start position:0% +do for four here and then you'd go up + + + align:start position:0% +do for four here and then you'd go up +and and then you'd have five comma six + + align:start position:0% +and and then you'd have five comma six + + + align:start position:0% +and and then you'd have five comma six +and then you would do seven comma I'm + + align:start position:0% +and then you would do seven comma I'm + + + align:start position:0% +and then you would do seven comma I'm +sorry five at seven comma nine right so + + align:start position:0% +sorry five at seven comma nine right so + + + align:start position:0% +sorry five at seven comma nine right so +this is the first time you actually have + + align:start position:0% +this is the first time you actually have + + + align:start position:0% +this is the first time you actually have +something interesting in the sense that + + align:start position:0% +something interesting in the sense that + + + align:start position:0% +something interesting in the sense that +the interval has a representation that + + align:start position:0% +the interval has a representation that + + + align:start position:0% +the interval has a representation that +only has two numbers in it whereas you + + align:start position:0% +only has two numbers in it whereas you + + + align:start position:0% +only has two numbers in it whereas you +actually have three people in that + + align:start position:0% +actually have three people in that + + + align:start position:0% +actually have three people in that +interval right and obviously this could + + align:start position:0% +interval right and obviously this could + + + align:start position:0% +interval right and obviously this could +be arbitrarily large in the context of + + align:start position:0% +be arbitrarily large in the context of + + + align:start position:0% +be arbitrarily large in the context of +people getting into a baseball game and + + align:start position:0% +people getting into a baseball game and + + + align:start position:0% +people getting into a baseball game and +so seven through nine and then finally + + align:start position:0% +so seven through nine and then finally + + + align:start position:0% +so seven through nine and then finally +here ten through ten right and so now + + align:start position:0% +here ten through ten right and so now + + + align:start position:0% +here ten through ten right and so now +you go ahead and you count and you + + align:start position:0% +you go ahead and you count and you + + + align:start position:0% +you go ahead and you count and you +realize that there's four intervals here + + align:start position:0% +realize that there's four intervals here + + + align:start position:0% +realize that there's four intervals here +and three intervals here and then you + + align:start position:0% +and three intervals here and then you + + + align:start position:0% +and three intervals here and then you +say I'm gonna go ahead and go with with + + align:start position:0% +say I'm gonna go ahead and go with with + + + align:start position:0% +say I'm gonna go ahead and go with with +the backwards and asking the the people + + align:start position:0% +the backwards and asking the the people + + + align:start position:0% +the backwards and asking the the people +who are well according to you backwards + + align:start position:0% +who are well according to you backwards + + + align:start position:0% +who are well according to you backwards +to flip their caps so we're all good all + + align:start position:0% +to flip their caps so we're all good all + + + align:start position:0% +to flip their caps so we're all good all +right so so I'm gonna show you code that + + align:start position:0% +right so so I'm gonna show you code that + + + align:start position:0% +right so so I'm gonna show you code that +that implements exactly this algorithm + + align:start position:0% +that implements exactly this algorithm + + + align:start position:0% +that implements exactly this algorithm +and while you see the code I want you to + + align:start position:0% +and while you see the code I want you to + + + align:start position:0% +and while you see the code I want you to +think about this harder question on this + + align:start position:0% +think about this harder question on this + + + align:start position:0% +think about this harder question on this +code is going to do exactly what we + + align:start position:0% +code is going to do exactly what we + + + align:start position:0% +code is going to do exactly what we +described it's going to go compute all + + align:start position:0% +described it's going to go compute all + + + align:start position:0% +described it's going to go compute all +of these things and it good is going to + + align:start position:0% +of these things and it good is going to + + + align:start position:0% +of these things and it good is going to +make a pass through the entire as you + + align:start position:0% +make a pass through the entire as you + + + align:start position:0% +make a pass through the entire as you +can imagine it's going to make a pass + + align:start position:0% +can imagine it's going to make a pass + + + align:start position:0% +can imagine it's going to make a pass +through this entire Python list or the + + align:start position:0% +through this entire Python list or the + + + align:start position:0% +through this entire Python list or the +set of this group of people there's a + + align:start position:0% +set of this group of people there's a + + + align:start position:0% +set of this group of people there's a +queue of people and it's going to do + + align:start position:0% +queue of people and it's going to do + + + align:start position:0% +queue of people and it's going to do +this computation then it's going to say + + align:start position:0% +this computation then it's going to say + + + align:start position:0% +this computation then it's going to say +4 is greater than 3 and and then it's + + align:start position:0% +4 is greater than 3 and and then it's + + + align:start position:0% +4 is greater than 3 and and then it's +going to go through and start calling + + align:start position:0% +going to go through and start calling + + + align:start position:0% +going to go through and start calling +out commands for each of the backward + + align:start position:0% +out commands for each of the backward + + + align:start position:0% +out commands for each of the backward +intervals so in some sense it's going to + + align:start position:0% +intervals so in some sense it's going to + + + align:start position:0% +intervals so in some sense it's going to +make two passes over the the list all + + align:start position:0% +make two passes over the the list all + + + align:start position:0% +make two passes over the the list all +right so the first pass is to get all of + + align:start position:0% +right so the first pass is to get all of + + + align:start position:0% +right so the first pass is to get all of +the intervals together then there's a + + align:start position:0% +the intervals together then there's a + + + align:start position:0% +the intervals together then there's a +check and then the second pass is to + + align:start position:0% +check and then the second pass is to + + + align:start position:0% +check and then the second pass is to +take those those back those backward + + align:start position:0% +take those those back those backward + + + align:start position:0% +take those those back those backward +intervals in this case and call out + + align:start position:0% +intervals in this case and call out + + + align:start position:0% +intervals in this case and call out +those commands all right so that's what + + align:start position:0% +those commands all right so that's what + + + align:start position:0% +those commands all right so that's what +I mean by two passes + + align:start position:0% +I mean by two passes + + + align:start position:0% +I mean by two passes +yeah brilliant brilliant + + align:start position:0% +yeah brilliant brilliant + + + align:start position:0% +yeah brilliant brilliant +you okay so so I was going to say if you + + align:start position:0% +you okay so so I was going to say if you + + + align:start position:0% +you okay so so I was going to say if you +didn't understand what ganado said + + align:start position:0% +didn't understand what ganado said + + + align:start position:0% +didn't understand what ganado said +wonderful because then you can you can + + align:start position:0% +wonderful because then you can you can + + + align:start position:0% +wonderful because then you can you can +you can you know think about the + + align:start position:0% +you can you know think about the + + + align:start position:0% +you can you know think about the +question I'm going to ask and ignore + + align:start position:0% +question I'm going to ask and ignore + + + align:start position:0% +question I'm going to ask and ignore +what he said and and and then we'll + + align:start position:0% +what he said and and and then we'll + + + align:start position:0% +what he said and and and then we'll +we'll get to the I guess the the more + + align:start position:0% +we'll get to the I guess the the more + + + align:start position:0% +we'll get to the I guess the the more +efficient code but what I was going to + + align:start position:0% +efficient code but what I was going to + + + align:start position:0% +efficient code but what I was going to +ask was is there a way that I'm looking + + align:start position:0% +ask was is there a way that I'm looking + + + align:start position:0% +ask was is there a way that I'm looking +at this and I'm just going and I'm gonna + + align:start position:0% +at this and I'm just going and I'm gonna + + + align:start position:0% +at this and I'm just going and I'm gonna +just start calling out by the moment I + + align:start position:0% +just start calling out by the moment I + + + align:start position:0% +just start calling out by the moment I +see that there's an interval okay the + + align:start position:0% +see that there's an interval okay the + + + align:start position:0% +see that there's an interval okay the +moment I see there's this like this is + + align:start position:0% +moment I see there's this like this is + + + align:start position:0% +moment I see there's this like this is +an interval and and I'm gonna make a + + align:start position:0% +an interval and and I'm gonna make a + + + align:start position:0% +an interval and and I'm gonna make a +call with respect to whether I'm going + + align:start position:0% +call with respect to whether I'm going + + + align:start position:0% +call with respect to whether I'm going +to call all the command or not all right + + align:start position:0% +to call all the command or not all right + + + align:start position:0% +to call all the command or not all right +and I'm going to do this in one pass + + align:start position:0% +and I'm going to do this in one pass + + + align:start position:0% +and I'm going to do this in one pass +through this through this array okay I + + align:start position:0% +through this through this array okay I + + + align:start position:0% +through this through this array okay I +want to do this in one pass through the + + align:start position:0% +want to do this in one pass through the + + + align:start position:0% +want to do this in one pass through the +array I want to look at this and I say I + + align:start position:0% +array I want to look at this and I say I + + + align:start position:0% +array I want to look at this and I say I +see the interval 0 0 all right is is + + align:start position:0% +see the interval 0 0 all right is is + + + align:start position:0% +see the interval 0 0 all right is is +that going to be something that I need + + align:start position:0% +that going to be something that I need + + + align:start position:0% +that going to be something that I need +to worry about in terms of that person + + align:start position:0% +to worry about in terms of that person + + + align:start position:0% +to worry about in terms of that person +having to flip the his cap and then I + + align:start position:0% +having to flip the his cap and then I + + + align:start position:0% +having to flip the his cap and then I +see BB and I say oh the interval is 1 + + align:start position:0% +see BB and I say oh the interval is 1 + + + align:start position:0% +see BB and I say oh the interval is 1 +comma 2 is that is that something I'm + + align:start position:0% +comma 2 is that is that something I'm + + + align:start position:0% +comma 2 is that is that something I'm +gonna have to deal with in terms of a + + align:start position:0% +gonna have to deal with in terms of a + + + align:start position:0% +gonna have to deal with in terms of a +command right and so someone else other + + align:start position:0% +command right and so someone else other + + + align:start position:0% +command right and so someone else other +than you not wrote I tell me if there's + + align:start position:0% +than you not wrote I tell me if there's + + + align:start position:0% +than you not wrote I tell me if there's +a there's a one pass algorithm and + + align:start position:0% +a there's a one pass algorithm and + + + align:start position:0% +a there's a one pass algorithm and +explain to me of why you can do this in + + align:start position:0% +explain to me of why you can do this in + + + align:start position:0% +explain to me of why you can do this in +one pass through the array and just in + + align:start position:0% +one pass through the array and just in + + + align:start position:0% +one pass through the array and just in +terms of code I'll preview this the + + align:start position:0% +terms of code I'll preview this the + + + align:start position:0% +terms of code I'll preview this the +first algorithm it needs according to my + + align:start position:0% +first algorithm it needs according to my + + + align:start position:0% +first algorithm it needs according to my +coding which is in grade 26 lines of + + align:start position:0% +coding which is in grade 26 lines of + + + align:start position:0% +coding which is in grade 26 lines of +code the second one needs eight lines of + + align:start position:0% +code the second one needs eight lines of + + + align:start position:0% +code the second one needs eight lines of +code alright so yeah go ahead + + align:start position:0% +code alright so yeah go ahead + + + align:start position:0% +code alright so yeah go ahead +how do you see the president rule there + + align:start position:0% +how do you see the president rule there + + + align:start position:0% +how do you see the president rule there +rule you know the second interval at the + + align:start position:0% +rule you know the second interval at the + + + align:start position:0% +rule you know the second interval at the +very least is gonna have the same number + + align:start position:0% +very least is gonna have the same number + + + align:start position:0% +very least is gonna have the same number +of like commands as the first one so you + + align:start position:0% +of like commands as the first one so you + + + align:start position:0% +of like commands as the first one so you +might as well always go at the second + + align:start position:0% +might as well always go at the second + + + align:start position:0% +might as well always go at the second +one so once you've identified what type + + align:start position:0% +one so once you've identified what type + + + align:start position:0% +one so once you've identified what type +the first interval is you iterate + + align:start position:0% +the first interval is you iterate + + + align:start position:0% +the first interval is you iterate +through the list see like and once you + + align:start position:0% +through the list see like and once you + + + align:start position:0% +through the list see like and once you +identify the person second intervals + + align:start position:0% +identify the person second intervals + + + align:start position:0% +identify the person second intervals +iterate through every type of the second + + align:start position:0% +iterate through every type of the second + + + align:start position:0% +iterate through every type of the second +interval and do a command for that Kevin + + align:start position:0% +interval and do a command for that Kevin + + + align:start position:0% +interval and do a command for that Kevin +so so you had it right and and kevin has + + align:start position:0% +so so you had it right and and kevin has + + + align:start position:0% +so so you had it right and and kevin has +it right as well so the observation here + + align:start position:0% +it right as well so the observation here + + + align:start position:0% +it right as well so the observation here +is actually the if I it was said a + + align:start position:0% +is actually the if I it was said a + + + align:start position:0% +is actually the if I it was said a +little bit differently by Kevin but I'm + + align:start position:0% +little bit differently by Kevin but I'm + + + align:start position:0% +little bit differently by Kevin but I'm +gonna say it a little bit differently + + align:start position:0% +gonna say it a little bit differently + + + align:start position:0% +gonna say it a little bit differently +and the observation is simply that that + + align:start position:0% +and the observation is simply that that + + + align:start position:0% +and the observation is simply that that +if you look at the very first + + align:start position:0% +if you look at the very first + + + align:start position:0% +if you look at the very first +orientation right the the very first + + align:start position:0% +orientation right the the very first + + + align:start position:0% +orientation right the the very first +orientation is something which at best + + align:start position:0% +orientation is something which at best + + + align:start position:0% +orientation is something which at best +is is going to do hat is going to be a + + align:start position:0% +is is going to do hat is going to be a + + + align:start position:0% +is is going to do hat is going to be a +tie right so if you if you had it ending + + align:start position:0% +tie right so if you if you had it ending + + + align:start position:0% +tie right so if you if you had it ending +at with 10 people 0 through 9 right then + + align:start position:0% +at with 10 people 0 through 9 right then + + + align:start position:0% +at with 10 people 0 through 9 right then +the number of forward intervals is the + + align:start position:0% +the number of forward intervals is the + + + align:start position:0% +the number of forward intervals is the +same as the number of backwards + + align:start position:0% +same as the number of backwards + + + align:start position:0% +same as the number of backwards +intervals okay and if you went here + + align:start position:0% +intervals okay and if you went here + + + align:start position:0% +intervals okay and if you went here +obviously the number of forward + + align:start position:0% +obviously the number of forward + + + align:start position:0% +obviously the number of forward +intervals is greater than the number of + + align:start position:0% +intervals is greater than the number of + + + align:start position:0% +intervals is greater than the number of +backwards intervals so you really only + + align:start position:0% +backwards intervals so you really only + + + align:start position:0% +backwards intervals so you really only +have to look at the first person in line + + align:start position:0% +have to look at the first person in line + + + align:start position:0% +have to look at the first person in line +to determine not to determine the + + align:start position:0% +to determine not to determine the + + + align:start position:0% +to determine not to determine the +intervals because you see the first + + align:start position:0% +intervals because you see the first + + + align:start position:0% +intervals because you see the first +person in line you have no idea what the + + align:start position:0% +person in line you have no idea what the + + + align:start position:0% +person in line you have no idea what the +intervals are that are coming after + + align:start position:0% +intervals are that are coming after + + + align:start position:0% +intervals are that are coming after +right I mean you can't you have to + + align:start position:0% +right I mean you can't you have to + + + align:start position:0% +right I mean you can't you have to +generate those intervals so you have to + + align:start position:0% +generate those intervals so you have to + + + align:start position:0% +generate those intervals so you have to +make your pass through the array but the + + align:start position:0% +make your pass through the array but the + + + align:start position:0% +make your pass through the array but the +first person in line gives it away in + + align:start position:0% +first person in line gives it away in + + + align:start position:0% +first person in line gives it away in +terms of what the final result is going + + align:start position:0% +terms of what the final result is going + + + align:start position:0% +terms of what the final result is going +to be with respect to your decision as + + align:start position:0% +to be with respect to your decision as + + + align:start position:0% +to be with respect to your decision as +to what set of commands you what set of + + align:start position:0% +to what set of commands you what set of + + + align:start position:0% +to what set of commands you what set of +commands you're going to call up right + + align:start position:0% +commands you're going to call up right + + + align:start position:0% +commands you're going to call up right +and so because this is an F you you you + + align:start position:0% +and so because this is an F you you you + + + align:start position:0% +and so because this is an F you you you +you basically say I'm gonna go and I'm + + align:start position:0% +you basically say I'm gonna go and I'm + + + align:start position:0% +you basically say I'm gonna go and I'm +going to make the people with the with + + align:start position:0% +going to make the people with the with + + + align:start position:0% +going to make the people with the with +the bees flip their flip their caps + + align:start position:0% +the bees flip their flip their caps + + + align:start position:0% +the bees flip their flip their caps +alright and that's that's a small + + align:start position:0% +alright and that's that's a small + + + align:start position:0% +alright and that's that's a small +observation in in terms of I it's inside + + align:start position:0% +observation in in terms of I it's inside + + + align:start position:0% +observation in in terms of I it's inside +but obviously + + align:start position:0% +but obviously + + + align:start position:0% +but obviously +it's potent in the sense that it's going + + align:start position:0% +it's potent in the sense that it's going + + + align:start position:0% +it's potent in the sense that it's going +to give you a one pass algorithm versus + + align:start position:0% +to give you a one pass algorithm versus + + + align:start position:0% +to give you a one pass algorithm versus +a two pass algorithm and as I mentioned + + align:start position:0% +a two pass algorithm and as I mentioned + + + align:start position:0% +a two pass algorithm and as I mentioned +it's going to give you a substantial + + align:start position:0% +it's going to give you a substantial + + + align:start position:0% +it's going to give you a substantial +reduction in the amount of code that you + + align:start position:0% +reduction in the amount of code that you + + + align:start position:0% +reduction in the amount of code that you +write all right + + align:start position:0% +write all right + + + align:start position:0% +write all right +um so I'm gonna show you a bunch of code + + align:start position:0% +um so I'm gonna show you a bunch of code + + + align:start position:0% +um so I'm gonna show you a bunch of code +now + + align:start position:0% +now + + + align:start position:0% +now +right so this is usually hard this is + + align:start position:0% +right so this is usually hard this is + + + align:start position:0% +right so this is usually hard this is +going to go by the way this this entire + + align:start position:0% +going to go by the way this this entire + + + align:start position:0% +going to go by the way this this entire +class and this is kind of my way of + + align:start position:0% +class and this is kind of my way of + + + align:start position:0% +class and this is kind of my way of +teaching at least this type of material + + align:start position:0% +teaching at least this type of material + + + align:start position:0% +teaching at least this type of material +that's algorithmic and has data + + align:start position:0% +that's algorithmic and has data + + + align:start position:0% +that's algorithmic and has data +structures and so on Internet I like + + align:start position:0% +structures and so on Internet I like + + + align:start position:0% +structures and so on Internet I like +explaining to people what they're going + + align:start position:0% +explaining to people what they're going + + + align:start position:0% +explaining to people what they're going +to see in the code without having to + + align:start position:0% +to see in the code without having to + + + align:start position:0% +to see in the code without having to +deal with Python syntax and you know + + align:start position:0% +deal with Python syntax and you know + + + align:start position:0% +deal with Python syntax and you know +worrying about whether it's while loops + + align:start position:0% +worrying about whether it's while loops + + + align:start position:0% +worrying about whether it's while loops +or for loops and things like that and + + align:start position:0% +or for loops and things like that and + + + align:start position:0% +or for loops and things like that and +tuples or arrays and things like that + + align:start position:0% +tuples or arrays and things like that + + + align:start position:0% +tuples or arrays and things like that +right so let's let's get into that good + + align:start position:0% +right so let's let's get into that good + + + align:start position:0% +right so let's let's get into that good +all right so the naive algorithm first + + align:start position:0% +all right so the naive algorithm first + + + align:start position:0% +all right so the naive algorithm first +okay so what you see here is an input so + + align:start position:0% +okay so what you see here is an input so + + + align:start position:0% +okay so what you see here is an input so +caps is is simply an input Python list + + align:start position:0% +caps is is simply an input Python list + + + align:start position:0% +caps is is simply an input Python list +that has as you can see from our + + align:start position:0% +that has as you can see from our + + + align:start position:0% +that has as you can see from our +examples the FS and the B's right and so + + align:start position:0% +examples the FS and the B's right and so + + + align:start position:0% +examples the FS and the B's right and so +f is for words and B is backwards and + + align:start position:0% +f is for words and B is backwards and + + + align:start position:0% +f is for words and B is backwards and +there's a couple of different Python + + align:start position:0% +there's a couple of different Python + + + align:start position:0% +there's a couple of different Python +lists so you can run them with different + + align:start position:0% +lists so you can run them with different + + + align:start position:0% +lists so you can run them with different +things and you know all of this + + align:start position:0% +things and you know all of this + + + align:start position:0% +things and you know all of this +hopefully is not at all surprising to + + align:start position:0% +hopefully is not at all surprising to + + + align:start position:0% +hopefully is not at all surprising to +you because we went through all of this + + align:start position:0% +you because we went through all of this + + + align:start position:0% +you because we went through all of this +in terms of the pseudocode right so the + + align:start position:0% +in terms of the pseudocode right so the + + + align:start position:0% +in terms of the pseudocode right so the +first initialization and I can just + + align:start position:0% +first initialization and I can just + + + align:start position:0% +first initialization and I can just +highlight that to make it easy so that's + + align:start position:0% +highlight that to make it easy so that's + + + align:start position:0% +highlight that to make it easy so that's +initialization and this part here the + + align:start position:0% +initialization and this part here the + + + align:start position:0% +initialization and this part here the +comment sort of gives it away is you're + + align:start position:0% +comment sort of gives it away is you're + + + align:start position:0% +comment sort of gives it away is you're +you're making a pass through the array + + align:start position:0% +you're making a pass through the array + + + align:start position:0% +you're making a pass through the array +computing the computing the intervals + + align:start position:0% +computing the computing the intervals + + + align:start position:0% +computing the computing the intervals +right and so so how do you actually get + + align:start position:0% +right and so so how do you actually get + + + align:start position:0% +right and so so how do you actually get +the intervals and there's one line of + + align:start position:0% +the intervals and there's one line of + + + align:start position:0% +the intervals and there's one line of +code that that does that I know by the + + align:start position:0% +code that that does that I know by the + + + align:start position:0% +code that that does that I know by the +way there's any questions about Python + + align:start position:0% +way there's any questions about Python + + + align:start position:0% +way there's any questions about Python +syntax you know just don't feel shy just + + align:start position:0% +syntax you know just don't feel shy just + + + align:start position:0% +syntax you know just don't feel shy just +just tell me ask me ask me a question + + align:start position:0% +just tell me ask me ask me a question + + + align:start position:0% +just tell me ask me ask me a question +and I'm happy to explain it I mean if + + align:start position:0% +and I'm happy to explain it I mean if + + + align:start position:0% +and I'm happy to explain it I mean if +I'm I don't want explain things that you + + align:start position:0% +I'm I don't want explain things that you + + + align:start position:0% +I'm I don't want explain things that you +all know obviously but if anyone of you + + align:start position:0% +all know obviously but if anyone of you + + + align:start position:0% +all know obviously but if anyone of you +doesn't know any particular thing please + + align:start position:0% +doesn't know any particular thing please + + + align:start position:0% +doesn't know any particular thing please +don't feel shy syntax is something that + + align:start position:0% +don't feel shy syntax is something that + + + align:start position:0% +don't feel shy syntax is something that +sometimes you even forget I mean I tend + + align:start position:0% +sometimes you even forget I mean I tend + + + align:start position:0% +sometimes you even forget I mean I tend +to forget things um so this thing here + + align:start position:0% +to forget things um so this thing here + + + align:start position:0% +to forget things um so this thing here +is is essentially something that that + + align:start position:0% +is is essentially something that that + + + align:start position:0% +is is essentially something that that +decides on when the what the intervals + + align:start position:0% +decides on when the what the intervals + + + align:start position:0% +decides on when the what the intervals +are and in the insight here is simple + + align:start position:0% +are and in the insight here is simple + + + align:start position:0% +are and in the insight here is simple +and you know that this interval ended + + align:start position:0% +and you know that this interval ended + + + align:start position:0% +and you know that this interval ended +when you see something here that is + + align:start position:0% +when you see something here that is + + + align:start position:0% +when you see something here that is +different from what the previous one is + + align:start position:0% +different from what the previous one is + + + align:start position:0% +different from what the previous one is +right so that's when you know so you + + align:start position:0% +right so that's when you know so you + + + align:start position:0% +right so that's when you know so you +generate the interval right you generate + + align:start position:0% +generate the interval right you generate + + + align:start position:0% +generate the interval right you generate +the interval when you you go and find + + align:start position:0% +the interval when you you go and find + + + align:start position:0% +the interval when you you go and find +something that is different from the + + align:start position:0% +something that is different from the + + + align:start position:0% +something that is different from the +current location that you're pointing to + + align:start position:0% +current location that you're pointing to + + + align:start position:0% +current location that you're pointing to +right so that's really what's going on + + align:start position:0% +right so that's really what's going on + + + align:start position:0% +right so that's really what's going on +out here you're in in this line you say + + align:start position:0% +out here you're in in this line you say + + + align:start position:0% +out here you're in in this line you say +you're setting a start here start is + + align:start position:0% +you're setting a start here start is + + + align:start position:0% +you're setting a start here start is +your counter and remember start is + + align:start position:0% +your counter and remember start is + + + align:start position:0% +your counter and remember start is +getting set again here + + align:start position:0% +getting set again here + + + align:start position:0% +getting set again here +initially it was set to zero and if you + + align:start position:0% +initially it was set to zero and if you + + + align:start position:0% +initially it was set to zero and if you +ever get to the point where you're + + align:start position:0% +ever get to the point where you're + + + align:start position:0% +ever get to the point where you're +looking at I it's the next thing you're + + align:start position:0% +looking at I it's the next thing you're + + + align:start position:0% +looking at I it's the next thing you're +looking at and if cap start which is the + + align:start position:0% +looking at and if cap start which is the + + + align:start position:0% +looking at and if cap start which is the +start of the interval is different from + + align:start position:0% +start of the interval is different from + + + align:start position:0% +start of the interval is different from +I it meant that the interval that began + + align:start position:0% +I it meant that the interval that began + + + align:start position:0% +I it meant that the interval that began +with start ended okay + + align:start position:0% +with start ended okay + + + align:start position:0% +with start ended okay +and so you essentially say well that + + align:start position:0% +and so you essentially say well that + + + align:start position:0% +and so you essentially say well that +that needs to end at I minus one because + + align:start position:0% +that needs to end at I minus one because + + + align:start position:0% +that needs to end at I minus one because +obviously cap start is different from + + align:start position:0% +obviously cap start is different from + + + align:start position:0% +obviously cap start is different from +cap size so this is the end of the + + align:start position:0% +cap size so this is the end of the + + + align:start position:0% +cap size so this is the end of the +interval right here all right and this + + align:start position:0% +interval right here all right and this + + + align:start position:0% +interval right here all right and this +particular thing is our interval is is + + align:start position:0% +particular thing is our interval is is + + + align:start position:0% +particular thing is our interval is is +is something that includes both these + + align:start position:0% +is something that includes both these + + + align:start position:0% +is something that includes both these +two numbers so it's not exactly that but + + align:start position:0% +two numbers so it's not exactly that but + + + align:start position:0% +two numbers so it's not exactly that but +it also includes where it might go + + align:start position:0% +it also includes where it might go + + + align:start position:0% +it also includes where it might go +it also includes whether this is an F or + + align:start position:0% +it also includes whether this is an F or + + + align:start position:0% +it also includes whether this is an F or +not so each of these things has I'm not + + align:start position:0% +not so each of these things has I'm not + + + align:start position:0% +not so each of these things has I'm not +gonna write it out for all of those + + align:start position:0% +gonna write it out for all of those + + + align:start position:0% +gonna write it out for all of those +things but I has the the orientation + + align:start position:0% +things but I has the the orientation + + + align:start position:0% +things but I has the the orientation +inside of it so that's what you have out + + align:start position:0% +inside of it so that's what you have out + + + align:start position:0% +inside of it so that's what you have out +here that's why we have three of these + + align:start position:0% +here that's why we have three of these + + + align:start position:0% +here that's why we have three of these +in this tuple right this is a tuple + + align:start position:0% +in this tuple right this is a tuple + + + align:start position:0% +in this tuple right this is a tuple +because it's got round brackets around + + align:start position:0% +because it's got round brackets around + + + align:start position:0% +because it's got round brackets around +it um I could have made it I could have + + align:start position:0% +it um I could have made it I could have + + + align:start position:0% +it um I could have made it I could have +made it a list if I wanted and so that's + + align:start position:0% +made it a list if I wanted and so that's + + + align:start position:0% +made it a list if I wanted and so that's +essentially what we have here and now + + align:start position:0% +essentially what we have here and now + + + align:start position:0% +essentially what we have here and now +here's what happens in this particular + + align:start position:0% +here's what happens in this particular + + + align:start position:0% +here's what happens in this particular +piece of code when you get to the end + + align:start position:0% +piece of code when you get to the end + + + align:start position:0% +piece of code when you get to the end +and you fall off the end so if you if + + align:start position:0% +and you fall off the end so if you if + + + align:start position:0% +and you fall off the end so if you if +you just end then this code essentially + + align:start position:0% +you just end then this code essentially + + + align:start position:0% +you just end then this code essentially +it skips over and doesn't it doesn't + + align:start position:0% +it skips over and doesn't it doesn't + + + align:start position:0% +it skips over and doesn't it doesn't +actually put in the last interval right + + align:start position:0% +actually put in the last interval right + + + align:start position:0% +actually put in the last interval right +because you don't see something when you + + align:start position:0% +because you don't see something when you + + + align:start position:0% +because you don't see something when you +come up here and you're off the end of + + align:start position:0% +come up here and you're off the end of + + + align:start position:0% +come up here and you're off the end of +the array you fall off the edge of the + + align:start position:0% +the array you fall off the edge of the + + + align:start position:0% +the array you fall off the edge of the +array you don't see a B that is + + align:start position:0% +array you don't see a B that is + + + align:start position:0% +array you don't see a B that is +different from F right so so this the if + + align:start position:0% +different from F right so so this the if + + + align:start position:0% +different from F right so so this the if +you just wrote that code so something + + align:start position:0% +you just wrote that code so something + + + align:start position:0% +you just wrote that code so something +that I'd say in many people would could + + align:start position:0% +that I'd say in many people would could + + + align:start position:0% +that I'd say in many people would could +would have a would have a quote bug + + align:start position:0% +would have a would have a quote bug + + + align:start position:0% +would have a would have a quote bug +where they won't add this part of the + + align:start position:0% +where they won't add this part of the + + + align:start position:0% +where they won't add this part of the +code here because I didn't realize this + + align:start position:0% +code here because I didn't realize this + + + align:start position:0% +code here because I didn't realize this +particular point that I made which and + + align:start position:0% +particular point that I made which and + + + align:start position:0% +particular point that I made which and +so that last interval doesn't get added + + align:start position:0% +so that last interval doesn't get added + + + align:start position:0% +so that last interval doesn't get added +in right and so you have a bit more code + + align:start position:0% +in right and so you have a bit more code + + + align:start position:0% +in right and so you have a bit more code +here that decides on the last interval + + align:start position:0% +here that decides on the last interval + + + align:start position:0% +here that decides on the last interval +and and then you count and then you go + + align:start position:0% +and and then you count and then you go + + + align:start position:0% +and and then you count and then you go +ahead and call the commands all right so + + align:start position:0% +ahead and call the commands all right so + + + align:start position:0% +ahead and call the commands all right so +this all looks good yeah very good with + + align:start position:0% +this all looks good yeah very good with + + + align:start position:0% +this all looks good yeah very good with +this is there a way that I could somehow + + align:start position:0% +this is there a way that I could somehow + + + align:start position:0% +this is there a way that I could somehow +eliminate these four lines of code which + + align:start position:0% +eliminate these four lines of code which + + + align:start position:0% +eliminate these four lines of code which +is a little bit annoying and and just do + + align:start position:0% +is a little bit annoying and and just do + + + align:start position:0% +is a little bit annoying and and just do +things in their rate how could i with a + + align:start position:0% +things in their rate how could i with a + + + align:start position:0% +things in their rate how could i with a +little trick I could eliminate those + + align:start position:0% +little trick I could eliminate those + + + align:start position:0% +little trick I could eliminate those +four lines of code I mean I might III + + align:start position:0% +four lines of code I mean I might III + + + align:start position:0% +four lines of code I mean I might III +need a little bit more you know quote + + align:start position:0% +need a little bit more you know quote + + + align:start position:0% +need a little bit more you know quote +pre-processing but how I eliminate that + + align:start position:0% + + + + align:start position:0% + +someone else I'll get you yep + + align:start position:0% + + + + align:start position:0% + +you can have an extra check wasn't it + + align:start position:0% +you can have an extra check wasn't it + + + align:start position:0% +you can have an extra check wasn't it +Tanisha + + align:start position:0% +Tanisha + + + align:start position:0% +Tanisha +so Kanishka says that before you reach + + align:start position:0% +so Kanishka says that before you reach + + + align:start position:0% +so Kanishka says that before you reach +the end of the array you are or when you + + align:start position:0% +the end of the array you are or when you + + + align:start position:0% +the end of the array you are or when you +reach the end of the array you go ahead + + align:start position:0% +reach the end of the array you go ahead + + + align:start position:0% +reach the end of the array you go ahead +and and and and do a check that you've + + align:start position:0% +and and and and do a check that you've + + + align:start position:0% +and and and and do a check that you've +reached the end and generate the + + align:start position:0% +reached the end and generate the + + + align:start position:0% +reached the end and generate the +interval inside of it it just kind of + + align:start position:0% +interval inside of it it just kind of + + + align:start position:0% +interval inside of it it just kind of +like moving this code inside of it right + + align:start position:0% +like moving this code inside of it right + + + align:start position:0% +like moving this code inside of it right +so that's that's reasonable I'm not sure + + align:start position:0% +so that's that's reasonable I'm not sure + + + align:start position:0% +so that's that's reasonable I'm not sure +that's going to be as good as the way + + align:start position:0% +that's going to be as good as the way + + + align:start position:0% +that's going to be as good as the way +I'm that I want and which average which + + align:start position:0% +I'm that I want and which average which + + + align:start position:0% +I'm that I want and which average which +I coded think about pre-processing think + + align:start position:0% +I coded think about pre-processing think + + + align:start position:0% +I coded think about pre-processing think +about taking the array yeah okay all + + align:start position:0% +about taking the array yeah okay all + + + align:start position:0% +about taking the array yeah okay all +right this how many chemins do we have + + align:start position:0% +right this how many chemins do we have + + + align:start position:0% +right this how many chemins do we have +here okay so so so I you could you could + + align:start position:0% +here okay so so so I you could you could + + + align:start position:0% +here okay so so so I you could you could +do this + + align:start position:0% +do this + + + align:start position:0% +do this +right so let me let me show you + + align:start position:0% +right so let me let me show you + + + align:start position:0% +right so let me let me show you +something that's a little bit more so + + align:start position:0% +something that's a little bit more so + + + align:start position:0% +something that's a little bit more so +that was a 26 lines of code and so this + + align:start position:0% +that was a 26 lines of code and so this + + + align:start position:0% +that was a 26 lines of code and so this +says this is the line that's interesting + + align:start position:0% +says this is the line that's interesting + + + align:start position:0% +says this is the line that's interesting +so I had F and B right and so I don't + + align:start position:0% +so I had F and B right and so I don't + + + align:start position:0% +so I had F and B right and so I don't +want to add F for be there but you know + + align:start position:0% +want to add F for be there but you know + + + align:start position:0% +want to add F for be there but you know +what is what is convenient to do as it + + align:start position:0% +what is what is convenient to do as it + + + align:start position:0% +what is what is convenient to do as it +turns out is to just have something that + + align:start position:0% +turns out is to just have something that + + + align:start position:0% +turns out is to just have something that +essentially says there's an ending point + + align:start position:0% +essentially says there's an ending point + + + align:start position:0% +essentially says there's an ending point +so you have an exclusive end to their a + + align:start position:0% +so you have an exclusive end to their a + + + align:start position:0% +so you have an exclusive end to their a +that is actually that not something that + + align:start position:0% +that is actually that not something that + + + align:start position:0% +that is actually that not something that +would crash if you try to access it + + align:start position:0% +would crash if you try to access it + + + align:start position:0% +would crash if you try to access it +right you've added you had n people in + + align:start position:0% +right you've added you had n people in + + + align:start position:0% +right you've added you had n people in +line and now you have effectively in n + + align:start position:0% +line and now you have effectively in n + + + align:start position:0% +line and now you have effectively in n +plus 1 people in line but that n plus 1 + + align:start position:0% +plus 1 people in line but that n plus 1 + + + align:start position:0% +plus 1 people in line but that n plus 1 +person is a dummy right or you know you + + align:start position:0% +person is a dummy right or you know you + + + align:start position:0% +person is a dummy right or you know you +can call them end and and then if you do + + align:start position:0% +can call them end and and then if you do + + + align:start position:0% +can call them end and and then if you do +that then that's it + + align:start position:0% +that then that's it + + + align:start position:0% +that then that's it +the previous code works right yeah you + + align:start position:0% +the previous code works right yeah you + + + align:start position:0% +the previous code works right yeah you +can just remove those four lines and + + align:start position:0% +can just remove those four lines and + + + align:start position:0% +can just remove those four lines and +you'll all just work right because your + + align:start position:0% +you'll all just work right because your + + + align:start position:0% +you'll all just work right because your +F or your B is not equal to end right so + + align:start position:0% +F or your B is not equal to end right so + + + align:start position:0% +F or your B is not equal to end right so +the the whatever you had at the end I'm + + align:start position:0% +the the whatever you had at the end I'm + + + align:start position:0% +the the whatever you had at the end I'm +sorry I'm overloading terms here + + align:start position:0% +sorry I'm overloading terms here + + + align:start position:0% +sorry I'm overloading terms here +whatever you had at the at the at the + + align:start position:0% +whatever you had at the at the at the + + + align:start position:0% +whatever you had at the at the at the +last element whether it was a it was a B + + align:start position:0% +last element whether it was a it was a B + + + align:start position:0% +last element whether it was a it was a B +which because it ended here or F when + + align:start position:0% +which because it ended here or F when + + + align:start position:0% +which because it ended here or F when +you equate that to E and D you're going + + align:start position:0% +you equate that to E and D you're going + + + align:start position:0% +you equate that to E and D you're going +to get an inequality and so that last + + align:start position:0% +to get an inequality and so that last + + + align:start position:0% +to get an inequality and so that last +interval gets generated okay so it's a + + align:start position:0% +interval gets generated okay so it's a + + + align:start position:0% +interval gets generated okay so it's a +small optimization Tony Hoare was a very + + align:start position:0% +small optimization Tony Hoare was a very + + + align:start position:0% +small optimization Tony Hoare was a very +famous computer scientist said that + + align:start position:0% +famous computer scientist said that + + + align:start position:0% +famous computer scientist said that +inside every program there's + + align:start position:0% +inside every program there's + + + align:start position:0% +inside every program there's +smaller program waiting to get out okay + + align:start position:0% +smaller program waiting to get out okay + + + align:start position:0% +smaller program waiting to get out okay +so so this is kind of one of the themes + + align:start position:0% +so so this is kind of one of the themes + + + align:start position:0% +so so this is kind of one of the themes +that I'd like to to harp on in this + + align:start position:0% +that I'd like to to harp on in this + + + align:start position:0% +that I'd like to to harp on in this +class which is it's nice to write + + align:start position:0% +class which is it's nice to write + + + align:start position:0% +class which is it's nice to write +compact code usually if you can write + + align:start position:0% +compact code usually if you can write + + + align:start position:0% +compact code usually if you can write +compact code there's fewer fewer bugs in + + align:start position:0% +compact code there's fewer fewer bugs in + + + align:start position:0% +compact code there's fewer fewer bugs in +it and you don't want to go overboard + + align:start position:0% +it and you don't want to go overboard + + + align:start position:0% +it and you don't want to go overboard +you don't want too many subtleties but + + align:start position:0% +you don't want too many subtleties but + + + align:start position:0% +you don't want too many subtleties but +it's nice to ride compact code and so + + align:start position:0% +it's nice to ride compact code and so + + + align:start position:0% +it's nice to ride compact code and so +this is a little bit more compact and + + align:start position:0% +this is a little bit more compact and + + + align:start position:0% +this is a little bit more compact and +and then finally here's the one pass + + align:start position:0% +and then finally here's the one pass + + + align:start position:0% +and then finally here's the one pass +algorithm right so the whole thing I + + align:start position:0% +algorithm right so the whole thing I + + + align:start position:0% +algorithm right so the whole thing I +said the please conform one pass is the + + align:start position:0% +said the please conform one pass is the + + + align:start position:0% +said the please conform one pass is the +is the the smarter algorithm that + + align:start position:0% +is the the smarter algorithm that + + + align:start position:0% +is the the smarter algorithm that +essentially says I look if I just look + + align:start position:0% +essentially says I look if I just look + + + align:start position:0% +essentially says I look if I just look +at the very first thing I'm going to I'm + + align:start position:0% +at the very first thing I'm going to I'm + + + align:start position:0% +at the very first thing I'm going to I'm +gonna be able to skip that and then move + + align:start position:0% +gonna be able to skip that and then move + + + align:start position:0% +gonna be able to skip that and then move +on right so this is fairly complicated I + + align:start position:0% +on right so this is fairly complicated I + + + align:start position:0% +on right so this is fairly complicated I +mean it's it do I you know the algorithm + + align:start position:0% +mean it's it do I you know the algorithm + + + align:start position:0% +mean it's it do I you know the algorithm +trying to map that to this code is + + align:start position:0% +trying to map that to this code is + + + align:start position:0% +trying to map that to this code is +non-trivial so we'll spend a minute or + + align:start position:0% +non-trivial so we'll spend a minute or + + + align:start position:0% +non-trivial so we'll spend a minute or +two on it right but here's here's how + + align:start position:0% +two on it right but here's here's how + + + align:start position:0% +two on it right but here's here's how +this works + + align:start position:0% +this works + + + align:start position:0% +this works +right and by the way just to make sure + + align:start position:0% +right and by the way just to make sure + + + align:start position:0% +right and by the way just to make sure +so I've repeated things here so the + + align:start position:0% +so I've repeated things here so the + + + align:start position:0% +so I've repeated things here so the +first the optimized algorithm for that + + align:start position:0% +first the optimized algorithm for that + + + align:start position:0% +first the optimized algorithm for that +particular example produce these first + + align:start position:0% +particular example produce these first + + + align:start position:0% +particular example produce these first +three commands and then the the one pass + + align:start position:0% +three commands and then the the one pass + + + align:start position:0% +three commands and then the the one pass +algorithm produce exactly the same + + align:start position:0% +algorithm produce exactly the same + + + align:start position:0% +algorithm produce exactly the same +commands right so this is good to do + + align:start position:0% +commands right so this is good to do + + + align:start position:0% +commands right so this is good to do +it's always nice to have a couple of + + align:start position:0% +it's always nice to have a couple of + + + align:start position:0% +it's always nice to have a couple of +different ways of solving a problem + + align:start position:0% +different ways of solving a problem + + + align:start position:0% +different ways of solving a problem +because then you can you can verify + + align:start position:0% +because then you can you can verify + + + align:start position:0% +because then you can you can verify +things right anyway so so this piece of + + align:start position:0% +things right anyway so so this piece of + + + align:start position:0% +things right anyway so so this piece of +code is essentially something that does + + align:start position:0% +code is essentially something that does + + + align:start position:0% +code is essentially something that does +the similar trick to what we had before + + align:start position:0% +the similar trick to what we had before + + + align:start position:0% +the similar trick to what we had before +in terms of adding I to the to the + + align:start position:0% +in terms of adding I to the to the + + + align:start position:0% +in terms of adding I to the to the +original list adding an element but + + align:start position:0% +original list adding an element but + + + align:start position:0% +original list adding an element but +we're not using E and D here we're + + align:start position:0% +we're not using E and D here we're + + + align:start position:0% +we're not using E and D here we're +actually saying I what what we want to + + align:start position:0% +actually saying I what what we want to + + + align:start position:0% +actually saying I what what we want to +do because we're going to go ahead and + + align:start position:0% +do because we're going to go ahead and + + + align:start position:0% +do because we're going to go ahead and +skip this anyway you know if you're + + align:start position:0% +skip this anyway you know if you're + + + align:start position:0% +skip this anyway you know if you're +going to skip the F so we whatever that + + align:start position:0% +going to skip the F so we whatever that + + + align:start position:0% +going to skip the F so we whatever that +is we could just sort of add up here + + align:start position:0% +is we could just sort of add up here + + + align:start position:0% +is we could just sort of add up here +right + + align:start position:0% +right + + + align:start position:0% +right +and it's + + align:start position:0% +and it's + + + align:start position:0% +and it's +that's that makes it easy you don't have + + align:start position:0% +that's that makes it easy you don't have + + + align:start position:0% +that's that makes it easy you don't have +to worry about what the what the actual + + align:start position:0% +to worry about what the what the actual + + + align:start position:0% +to worry about what the what the actual +characters are and and cooking up this e + + align:start position:0% +characters are and and cooking up this e + + + align:start position:0% +characters are and and cooking up this e +and D which is different from the F for + + align:start position:0% +and D which is different from the F for + + + align:start position:0% +and D which is different from the F for +the B because you know hey it's possible + + align:start position:0% +the B because you know hey it's possible + + + align:start position:0% +the B because you know hey it's possible +that that that people might use whatever + + align:start position:0% +that that that people might use whatever + + + align:start position:0% +that that that people might use whatever +they want to represent a forward cap or + + align:start position:0% +they want to represent a forward cap or + + + align:start position:0% +they want to represent a forward cap or +a backward cap so this is very clean you + + align:start position:0% +a backward cap so this is very clean you + + + align:start position:0% +a backward cap so this is very clean you +go ahead and put exactly that over here + + align:start position:0% +go ahead and put exactly that over here + + + align:start position:0% +go ahead and put exactly that over here +you know you're gonna skip that interval + + align:start position:0% +you know you're gonna skip that interval + + + align:start position:0% +you know you're gonna skip that interval +because of the you want to skip the + + align:start position:0% +because of the you want to skip the + + + align:start position:0% +because of the you want to skip the +first the first interval effectively + + align:start position:0% +first the first interval effectively + + + align:start position:0% +first the first interval effectively +because that medalta them allows you to + + align:start position:0% +because that medalta them allows you to + + + align:start position:0% +because that medalta them allows you to +do and then this part here is is doing + + align:start position:0% +do and then this part here is is doing + + + align:start position:0% +do and then this part here is is doing +what we had before + + align:start position:0% +what we had before + + + align:start position:0% +what we had before +we're not even generating the intervals + + align:start position:0% +we're not even generating the intervals + + + align:start position:0% +we're not even generating the intervals +we're just directly making the commands + + align:start position:0% +we're just directly making the commands + + + align:start position:0% +we're just directly making the commands +right so there's no tuples in terms of + + align:start position:0% +right so there's no tuples in terms of + + + align:start position:0% +right so there's no tuples in terms of +the tuples and depending of the + + align:start position:0% +the tuples and depending of the + + + align:start position:0% +the tuples and depending of the +intervals data structure that we had + + align:start position:0% +intervals data structure that we had + + + align:start position:0% +intervals data structure that we had +it's all it's all gone I'm just going to + + align:start position:0% +it's all it's all gone I'm just going to + + + align:start position:0% +it's all it's all gone I'm just going to +go ahead and and fire off these commands + + align:start position:0% +go ahead and and fire off these commands + + + align:start position:0% +go ahead and and fire off these commands +right and those commands are are they're + + align:start position:0% +right and those commands are are they're + + + align:start position:0% +right and those commands are are they're +written in kind of a funny way right + + align:start position:0% +written in kind of a funny way right + + + align:start position:0% +written in kind of a funny way right +because I I'm going to go ahead and if I + + align:start position:0% +because I I'm going to go ahead and if I + + + align:start position:0% +because I I'm going to go ahead and if I +wanted to print these things out you'd + + align:start position:0% +wanted to print these things out you'd + + + align:start position:0% +wanted to print these things out you'd +have to do this in this funny way if + + align:start position:0% +have to do this in this funny way if + + + align:start position:0% +have to do this in this funny way if +you're willing to wait and collect up + + align:start position:0% +you're willing to wait and collect up + + + align:start position:0% +you're willing to wait and collect up +the intervals you could certainly do + + align:start position:0% +the intervals you could certainly do + + + align:start position:0% +the intervals you could certainly do +that right but this is absolutely the + + align:start position:0% +that right but this is absolutely the + + + align:start position:0% +that right but this is absolutely the +most compact code that I could think of + + align:start position:0% +most compact code that I could think of + + + align:start position:0% +most compact code that I could think of +and I'm printing a command in two + + align:start position:0% +and I'm printing a command in two + + + align:start position:0% +and I'm printing a command in two +different parts right I'm printing the + + align:start position:0% +different parts right I'm printing the + + + align:start position:0% +different parts right I'm printing the +first part of the command that says + + align:start position:0% +first part of the command that says + + + align:start position:0% +first part of the command that says +people in positions and that's the start + + align:start position:0% +people in positions and that's the start + + + align:start position:0% +people in positions and that's the start +of the interval I write and I'm just + + align:start position:0% +of the interval I write and I'm just + + + align:start position:0% +of the interval I write and I'm just +using a Python constructor this is this + + align:start position:0% +using a Python constructor this is this + + + align:start position:0% +using a Python constructor this is this +E&D here is is something that the print + + align:start position:0% +E&D here is is something that the print + + + align:start position:0% +E&D here is is something that the print +command can recognize and this simply + + align:start position:0% +command can recognize and this simply + + + align:start position:0% +command can recognize and this simply +says don't give me a newline I want to + + align:start position:0% +says don't give me a newline I want to + + + align:start position:0% +says don't give me a newline I want to +print it exactly as you saw from when I + + align:start position:0% +print it exactly as you saw from when I + + + align:start position:0% +print it exactly as you saw from when I +ran the code the printing was exactly + + align:start position:0% +ran the code the printing was exactly + + + align:start position:0% +ran the code the printing was exactly +the same as the original algorithm right + + align:start position:0% +the same as the original algorithm right + + + align:start position:0% +the same as the original algorithm right +and so this e and E simply says don't + + align:start position:0% +and so this e and E simply says don't + + + align:start position:0% +and so this e and E simply says don't +print a new line at the end of of people + + align:start position:0% +print a new line at the end of of people + + + align:start position:0% +print a new line at the end of of people +and positions you know whatever this + + align:start position:0% +and positions you know whatever this + + + align:start position:0% +and positions you know whatever this +number is call it seven and and you + + align:start position:0% +number is call it seven and and you + + + align:start position:0% +number is call it seven and and you +don't print a new line and then you go + + align:start position:0% +don't print a new line and then you go + + + align:start position:0% +don't print a new line and then you go +you have it space here because you + + align:start position:0% +you have it space here because you + + + align:start position:0% +you have it space here because you +didn't print a new line or or a space + + align:start position:0% +didn't print a new line or or a space + + + align:start position:0% +didn't print a new line or or a space +and you go through I minus one which is + + align:start position:0% +and you go through I minus one which is + + + align:start position:0% +and you go through I minus one which is +exactly the same as we had before you + + align:start position:0% +exactly the same as we had before you + + + align:start position:0% +exactly the same as we had before you +only discovered that + + align:start position:0% +only discovered that + + + align:start position:0% +only discovered that +at the end of an interval and after you + + align:start position:0% +at the end of an interval and after you + + + align:start position:0% +at the end of an interval and after you +see the person that comes after the + + align:start position:0% +see the person that comes after the + + + align:start position:0% +see the person that comes after the +interval right so you have to go back to + + align:start position:0% +interval right so you have to go back to + + + align:start position:0% +interval right so you have to go back to +I minus one so this makes sense any + + align:start position:0% +I minus one so this makes sense any + + + align:start position:0% +I minus one so this makes sense any +questions about this code yeah plus + + align:start position:0% +questions about this code yeah plus + + + align:start position:0% +questions about this code yeah plus +there is a concatenation and you have + + align:start position:0% +there is a concatenation and you have + + + align:start position:0% +there is a concatenation and you have +two lists caps as a list and when you + + align:start position:0% +two lists caps as a list and when you + + + align:start position:0% +two lists caps as a list and when you +use a plus operator in Python the you + + align:start position:0% +use a plus operator in Python the you + + + align:start position:0% +use a plus operator in Python the you +you can only add things that are of the + + align:start position:0% +you can only add things that are of the + + + align:start position:0% +you can only add things that are of the +same type okay and so caps is a is a + + align:start position:0% +same type okay and so caps is a is a + + + align:start position:0% +same type okay and so caps is a is a +list and caps 0 is an element of the + + align:start position:0% +list and caps 0 is an element of the + + + align:start position:0% +list and caps 0 is an element of the +list and so you need to make it a list + + align:start position:0% +list and so you need to make it a list + + + align:start position:0% +list and so you need to make it a list +in order to use the plus operator you + + align:start position:0% +in order to use the plus operator you + + + align:start position:0% +in order to use the plus operator you +dis also other things you could do using + + align:start position:0% +dis also other things you could do using + + + align:start position:0% +dis also other things you could do using +a pen for example right so you could + + align:start position:0% +a pen for example right so you could + + + align:start position:0% +a pen for example right so you could +take that line and you can do caps tour + + align:start position:0% +take that line and you can do caps tour + + + align:start position:0% +take that line and you can do caps tour +the pen cap zero right and you wouldn't + + align:start position:0% +the pen cap zero right and you wouldn't + + + align:start position:0% +the pen cap zero right and you wouldn't +need all of the square brackets but you + + align:start position:0% +need all of the square brackets but you + + + align:start position:0% +need all of the square brackets but you +know that's just neither here or not + + align:start position:0% +know that's just neither here or not + + + align:start position:0% +know that's just neither here or not +there but I was no obviously not + + align:start position:0% +there but I was no obviously not + + + align:start position:0% +there but I was no obviously not +answering your question so go ahead yeah + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% + + + + align:start position:0% + +but but it's ok because I remember the + + align:start position:0% +but but it's ok because I remember the + + + align:start position:0% +but but it's ok because I remember the +if statement and is is going to skip the + + align:start position:0% +if statement and is is going to skip the + + + align:start position:0% +if statement and is is going to skip the +this one too so if I had two F's in the + + align:start position:0% +this one too so if I had two F's in the + + + align:start position:0% +this one too so if I had two F's in the +beginning I think your question is what + + align:start position:0% +beginning I think your question is what + + + align:start position:0% +beginning I think your question is what +would happen if I had two F's or three + + align:start position:0% +would happen if I had two F's or three + + + align:start position:0% +would happen if I had two F's or three +FS in the beginning right so I'm going + + align:start position:0% +FS in the beginning right so I'm going + + + align:start position:0% +FS in the beginning right so I'm going +to go ahead and first thing I'm going to + + align:start position:0% +to go ahead and first thing I'm going to + + + align:start position:0% +to go ahead and first thing I'm going to +do is I'm going to put an F at the end + + align:start position:0% +do is I'm going to put an F at the end + + + align:start position:0% +do is I'm going to put an F at the end +here and then maybe there's a bunch of + + align:start position:0% +here and then maybe there's a bunch of + + + align:start position:0% +here and then maybe there's a bunch of +stuff but then the nice thing is that + + align:start position:0% +stuff but then the nice thing is that + + + align:start position:0% +stuff but then the nice thing is that +I'll skip this f2 because because the + + align:start position:0% +I'll skip this f2 because because the + + + align:start position:0% +I'll skip this f2 because because the +not equal to on is not going to is not + + align:start position:0% +not equal to on is not going to is not + + + align:start position:0% +not equal to on is not going to is not +going to fire right right the next line + + align:start position:0% +going to fire right right the next line + + + align:start position:0% +going to fire right right the next line +the caps I not equal to I minus one this + + align:start position:0% +the caps I not equal to I minus one this + + + align:start position:0% +the caps I not equal to I minus one this +is this is going to be equal to so I'm + + align:start position:0% +is this is going to be equal to so I'm + + + align:start position:0% +is this is going to be equal to so I'm +going to go ahead and go to the next + + align:start position:0% +going to go ahead and go to the next + + + align:start position:0% +going to go ahead and go to the next +iteration of the loop that makes sense + + align:start position:0% +iteration of the loop that makes sense + + + align:start position:0% +iteration of the loop that makes sense +did people understand fadis question + + align:start position:0% +did people understand fadis question + + + align:start position:0% +did people understand fadis question +right it was a good question right so + + align:start position:0% +right it was a good question right so + + + align:start position:0% +right it was a good question right so +the question was you I you skipped the + + align:start position:0% +the question was you I you skipped the + + + align:start position:0% +the question was you I you skipped the +first one but what is making you skip + + align:start position:0% +first one but what is making you skip + + + align:start position:0% +first one but what is making you skip +this one because you want to skip the + + align:start position:0% +this one because you want to skip the + + + align:start position:0% +this one because you want to skip the +first interval correct and so that if + + align:start position:0% +first interval correct and so that if + + + align:start position:0% +first interval correct and so that if +statement is making you do that alright + + align:start position:0% +statement is making you do that alright + + + align:start position:0% +statement is making you do that alright +good so as you can see even a fairly + + align:start position:0% +good so as you can see even a fairly + + + align:start position:0% +good so as you can see even a fairly +straightforward puzzle this is + + align:start position:0% +straightforward puzzle this is + + + align:start position:0% +straightforward puzzle this is +the simplest puzzle we're going to do + + align:start position:0% +the simplest puzzle we're going to do + + + align:start position:0% +the simplest puzzle we're going to do +here right is the first one you know and + + align:start position:0% +here right is the first one you know and + + + align:start position:0% +here right is the first one you know and +there's nuances associated with how you + + align:start position:0% +there's nuances associated with how you + + + align:start position:0% +there's nuances associated with how you +solve it but also how you code it right + + align:start position:0% +solve it but also how you code it right + + + align:start position:0% +solve it but also how you code it right +and this is kind of I said you know my + + align:start position:0% +and this is kind of I said you know my + + + align:start position:0% +and this is kind of I said you know my +this was my Eureka moment you know a few + + align:start position:0% +this was my Eureka moment you know a few + + + align:start position:0% +this was my Eureka moment you know a few +years ago but I said I think the way you + + align:start position:0% +years ago but I said I think the way you + + + align:start position:0% +years ago but I said I think the way you +want to teach programming is is is at + + align:start position:0% +want to teach programming is is is at + + + align:start position:0% +want to teach programming is is is at +least some some aspects of programming + + align:start position:0% +least some some aspects of programming + + + align:start position:0% +least some some aspects of programming +is in this fashion right anyway good so + + align:start position:0% +is in this fashion right anyway good so + + + align:start position:0% +is in this fashion right anyway good so +we're done with this any questions about + + align:start position:0% +we're done with this any questions about + + + align:start position:0% +we're done with this any questions about +this puzzle all right + + align:start position:0% + + + + align:start position:0% + +you \ No newline at end of file diff --git a/1ItXXlqK6eE.txt b/1ItXXlqK6eE.txt new file mode 100644 index 0000000000000000000000000000000000000000..8545447461b2e24a4e02c347b6757b44ec84f7b8 --- /dev/null +++ b/1ItXXlqK6eE.txt @@ -0,0 +1,9056 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT open courseware continue + + align:start position:0% +will help MIT open courseware continue + + + align:start position:0% +will help MIT open courseware continue +to offer highquality educational + + align:start position:0% +to offer highquality educational + + + align:start position:0% +to offer highquality educational +resources for free to make a donation or + + align:start position:0% +resources for free to make a donation or + + + align:start position:0% +resources for free to make a donation or +view additional materials from hundreds + + align:start position:0% +view additional materials from hundreds + + + align:start position:0% +view additional materials from hundreds +of MIT courses visit MIT open courseware + + align:start position:0% +of MIT courses visit MIT open courseware + + + align:start position:0% +of MIT courses visit MIT open courseware +at + + align:start position:0% + + + + align:start position:0% + +ocw.mit.edu + + align:start position:0% + + + + align:start position:0% + +so this is a this is just one person's + + align:start position:0% +so this is a this is just one person's + + + align:start position:0% +so this is a this is just one person's +rendition of a Gollum a Gollum is sort + + align:start position:0% +rendition of a Gollum a Gollum is sort + + + align:start position:0% +rendition of a Gollum a Gollum is sort +of uh the slave uh Rabbi low and U of + + align:start position:0% +of uh the slave uh Rabbi low and U of + + + align:start position:0% +of uh the slave uh Rabbi low and U of +Prague and it's a tale of uh + + align:start position:0% +Prague and it's a tale of uh + + + align:start position:0% +Prague and it's a tale of uh +a an individual made out of clay a a + + align:start position:0% +a an individual made out of clay a a + + + align:start position:0% +a an individual made out of clay a a +automaton made out of clay to carry out + + align:start position:0% +automaton made out of clay to carry out + + + align:start position:0% +automaton made out of clay to carry out +the the duties but it uh gets out of + + align:start position:0% +the the duties but it uh gets out of + + + align:start position:0% +the the duties but it uh gets out of +control while a good Rabbi is uh uh at + + align:start position:0% +control while a good Rabbi is uh uh at + + + align:start position:0% +control while a good Rabbi is uh uh at +uh Sho and uh nobody knows how to stop + + align:start position:0% +uh Sho and uh nobody knows how to stop + + + align:start position:0% +uh Sho and uh nobody knows how to stop +the thing so it's kind of uh running + + align:start position:0% +the thing so it's kind of uh running + + + align:start position:0% +the thing so it's kind of uh running +around a muuk and this is a problem and + + align:start position:0% +around a muuk and this is a problem and + + + align:start position:0% +around a muuk and this is a problem and +uh only only the rabbi knows how to shut + + align:start position:0% +uh only only the rabbi knows how to shut + + + align:start position:0% +uh only only the rabbi knows how to shut +it down um and so uh this is a kind of a + + align:start position:0% +it down um and so uh this is a kind of a + + + align:start position:0% +it down um and so uh this is a kind of a +a dominant metaphor for this book is + + align:start position:0% +a dominant metaphor for this book is + + + align:start position:0% +a dominant metaphor for this book is +this this concept of this this + + align:start position:0% +this this concept of this this + + + align:start position:0% +this this concept of this this +mechanical entity that that we create + + align:start position:0% +mechanical entity that that we create + + + align:start position:0% +mechanical entity that that we create +for our + + align:start position:0% +for our + + + align:start position:0% +for our +own to improve our + + align:start position:0% +own to improve our + + + align:start position:0% +own to improve our +lives but uh you know improve our lives + + align:start position:0% +lives but uh you know improve our lives + + + align:start position:0% +lives but uh you know improve our lives +through doing the chores and you know + + align:start position:0% +through doing the chores and you know + + + align:start position:0% +through doing the chores and you know +bringing the water up and all these + + align:start position:0% +bringing the water up and all these + + + align:start position:0% +bringing the water up and all these +sorts of things but it's not as simple + + align:start position:0% +sorts of things but it's not as simple + + + align:start position:0% +sorts of things but it's not as simple +as just making a lot of these things and + + align:start position:0% +as just making a lot of these things and + + + align:start position:0% +as just making a lot of these things and +just hoping that you know they'll all go + + align:start position:0% +just hoping that you know they'll all go + + + align:start position:0% +just hoping that you know they'll all go +out and do uh or intending that they'll + + align:start position:0% +out and do uh or intending that they'll + + + align:start position:0% +out and do uh or intending that they'll +go out and do everything that we intend + + align:start position:0% +go out and do everything that we intend + + + align:start position:0% +go out and do everything that we intend +them to do but nothing else because + + align:start position:0% +them to do but nothing else because + + + align:start position:0% +them to do but nothing else because +there are there are tremend mendous + + align:start position:0% +there are there are tremend mendous + + + align:start position:0% +there are there are tremend mendous +impacts through the use of mechanical + + align:start position:0% +impacts through the use of mechanical + + + align:start position:0% +impacts through the use of mechanical +devices and and not just mechanical in + + align:start position:0% +devices and and not just mechanical in + + + align:start position:0% +devices and and not just mechanical in +the sense of uh the traditional sense of + + align:start position:0% +the sense of uh the traditional sense of + + + align:start position:0% +the sense of uh the traditional sense of +machine as Laura says here the the + + align:start position:0% +machine as Laura says here the the + + + align:start position:0% +machine as Laura says here the the +concept of machine is + + align:start position:0% +concept of machine is + + + align:start position:0% +concept of machine is +changing the processing of information + + align:start position:0% +changing the processing of information + + + align:start position:0% +changing the processing of information +is a mechanical + + align:start position:0% +is a mechanical + + + align:start position:0% +is a mechanical +process and so machines are beginning to + + align:start position:0% +process and so machines are beginning to + + + align:start position:0% +process and so machines are beginning to +be thought of or have long been thought + + align:start position:0% +be thought of or have long been thought + + + align:start position:0% +be thought of or have long been thought +of In wier's Time as uh also devices + + align:start position:0% +of In wier's Time as uh also devices + + + align:start position:0% +of In wier's Time as uh also devices +which are + + align:start position:0% +which are + + + align:start position:0% +which are +electronic and primarily uh working + + align:start position:0% +electronic and primarily uh working + + + align:start position:0% +electronic and primarily uh working +through electronic uh uh + + align:start position:0% +through electronic uh uh + + + align:start position:0% +through electronic uh uh +systems okay so uh this is a little + + align:start position:0% +systems okay so uh this is a little + + + align:start position:0% +systems okay so uh this is a little +essay uh that he wrote it's a very + + align:start position:0% +essay uh that he wrote it's a very + + + align:start position:0% +essay uh that he wrote it's a very +yeasty little book it's got lots and + + align:start position:0% +yeasty little book it's got lots and + + + align:start position:0% +yeasty little book it's got lots and +lots of little topics in it it's not + + align:start position:0% +lots of little topics in it it's not + + + align:start position:0% +lots of little topics in it it's not +meant as a uh uh technical although as + + align:start position:0% +meant as a uh uh technical although as + + + align:start position:0% +meant as a uh uh technical although as +as La said there there are some things + + align:start position:0% +as La said there there are some things + + + align:start position:0% +as La said there there are some things +in it that are uh uh + + align:start position:0% +in it that are uh uh + + + align:start position:0% +in it that are uh uh +conceptually uh a little more a little + + align:start position:0% +conceptually uh a little more a little + + + align:start position:0% +conceptually uh a little more a little +beyond the average readers um but the + + align:start position:0% +beyond the average readers um but the + + + align:start position:0% +beyond the average readers um but the +book itself is really just trying to + + align:start position:0% +book itself is really just trying to + + + align:start position:0% +book itself is really just trying to +talk a little bit about technology in + + align:start position:0% +talk a little bit about technology in + + + align:start position:0% +talk a little bit about technology in +the world that we're creating through it + + align:start position:0% +the world that we're creating through it + + + align:start position:0% +the world that we're creating through it +and uh weiner was a deeply uh he was a + + align:start position:0% +and uh weiner was a deeply uh he was a + + + align:start position:0% +and uh weiner was a deeply uh he was a +thinking person who thought deeply about + + align:start position:0% +thinking person who thought deeply about + + + align:start position:0% +thinking person who thought deeply about +uh a whole range of things and + + align:start position:0% +uh a whole range of things and + + + align:start position:0% +uh a whole range of things and +um uh he's a uh uh + + align:start position:0% +um uh he's a uh uh + + + align:start position:0% +um uh he's a uh uh +a key person in the creation of the + + align:start position:0% +a key person in the creation of the + + + align:start position:0% +a key person in the creation of the +field of + + align:start position:0% +field of + + + align:start position:0% +field of +cybernetics uh his book + + align:start position:0% +cybernetics uh his book + + + align:start position:0% +cybernetics uh his book +cybernetics uh which is + + align:start position:0% +cybernetics uh which is + + + align:start position:0% +cybernetics uh which is +uh uh a the subtitle you can see control + + align:start position:0% +uh uh a the subtitle you can see control + + + align:start position:0% +uh uh a the subtitle you can see control +and communication in the animal and the + + align:start position:0% +and communication in the animal and the + + + align:start position:0% +and communication in the animal and the +Machine so the concept that we can + + align:start position:0% +Machine so the concept that we can + + + align:start position:0% +Machine so the concept that we can +transfer certain sorts of understandings + + align:start position:0% +transfer certain sorts of understandings + + + align:start position:0% +transfer certain sorts of understandings +we get from one location to another + + align:start position:0% +we get from one location to another + + + align:start position:0% +we get from one location to another +location is Central here and so we can + + align:start position:0% +location is Central here and so we can + + + align:start position:0% +location is Central here and so we can +learn we can learn about Mechanical + + align:start position:0% +learn we can learn about Mechanical + + + align:start position:0% +learn we can learn about Mechanical +Devices by studying biological entities + + align:start position:0% +Devices by studying biological entities + + + align:start position:0% +Devices by studying biological entities +and we can learn about biological + + align:start position:0% +and we can learn about biological + + + align:start position:0% +and we can learn about biological +entities by studying mechanical + + align:start position:0% +entities by studying mechanical + + + align:start position:0% +entities by studying mechanical +devices and the notion of how organisms + + align:start position:0% +devices and the notion of how organisms + + + align:start position:0% +devices and the notion of how organisms +control themselves can tell us lots and + + align:start position:0% +control themselves can tell us lots and + + + align:start position:0% +control themselves can tell us lots and +lots of things about how mechanical + + align:start position:0% +lots of things about how mechanical + + + align:start position:0% +lots of things about how mechanical +devices uh can be controlled + + align:start position:0% +devices uh can be controlled + + + align:start position:0% +devices uh can be controlled +and can also be + + align:start position:0% +and can also be + + + align:start position:0% +and can also be +self-regulating so these are these are + + align:start position:0% +self-regulating so these are these are + + + align:start position:0% +self-regulating so these are these are +areas that U are of of prime importance + + align:start position:0% +areas that U are of of prime importance + + + align:start position:0% +areas that U are of of prime importance +to him and that's sort of in the + + align:start position:0% +to him and that's sort of in the + + + align:start position:0% +to him and that's sort of in the +background of his thinking here is this + + align:start position:0% +background of his thinking here is this + + + align:start position:0% +background of his thinking here is this +whole question of U uh cybernetics and + + align:start position:0% +whole question of U uh cybernetics and + + + align:start position:0% +whole question of U uh cybernetics and +cybernetic + + align:start position:0% +cybernetic + + + align:start position:0% +cybernetic +control + + align:start position:0% +control + + + align:start position:0% +control +uh so U as Laura said the uh he he + + align:start position:0% +uh so U as Laura said the uh he he + + + align:start position:0% +uh so U as Laura said the uh he he +mentions it's a part of the scientist uh + + align:start position:0% +mentions it's a part of the scientist uh + + + align:start position:0% +mentions it's a part of the scientist uh +this is from page five to entertain + + align:start position:0% +this is from page five to entertain + + + align:start position:0% +this is from page five to entertain +heretical and forbidden opinions + + align:start position:0% +heretical and forbidden opinions + + + align:start position:0% +heretical and forbidden opinions +experimentally I mean weer has a sense + + align:start position:0% +experimentally I mean weer has a sense + + + align:start position:0% +experimentally I mean weer has a sense +of humor so some of this is he he he + + align:start position:0% +of humor so some of this is he he he + + + align:start position:0% +of humor so some of this is he he he +says this you know for impact and he's + + align:start position:0% +says this you know for impact and he's + + + align:start position:0% +says this you know for impact and he's +also aware that you know it's it's + + align:start position:0% +also aware that you know it's it's + + + align:start position:0% +also aware that you know it's it's +there's there's a element of humor + + align:start position:0% +there's there's a element of humor + + + align:start position:0% +there's there's a element of humor +behind this but uh the fact is that most + + align:start position:0% +behind this but uh the fact is that most + + + align:start position:0% +behind this but uh the fact is that most +people as he says when you say how + + align:start position:0% +people as he says when you say how + + + align:start position:0% +people as he says when you say how +machines and and humans or organisms + + align:start position:0% +machines and and humans or organisms + + + align:start position:0% +machines and and humans or organisms +alike just say oh you you can't talk + + align:start position:0% +alike just say oh you you can't talk + + + align:start position:0% +alike just say oh you you can't talk +about these two they just you know don't + + align:start position:0% +about these two they just you know don't + + + align:start position:0% +about these two they just you know don't +they're entirely different uh uh Realms + + align:start position:0% +they're entirely different uh uh Realms + + + align:start position:0% +they're entirely different uh uh Realms +and any comparison is going to be + + align:start position:0% +and any comparison is going to be + + + align:start position:0% +and any comparison is going to be +superficial and so uh and and sometimes + + align:start position:0% +superficial and so uh and and sometimes + + + align:start position:0% +superficial and so uh and and sometimes +people make these statements on sort of + + align:start position:0% +people make these statements on sort of + + + align:start position:0% +people make these statements on sort of +religious grounds and so that's why he + + align:start position:0% +religious grounds and so that's why he + + + align:start position:0% +religious grounds and so that's why he +says uh entertain heral well in + + align:start position:0% +says uh entertain heral well in + + + align:start position:0% +says uh entertain heral well in +science uh I mean heresy doesn't really + + align:start position:0% +science uh I mean heresy doesn't really + + + align:start position:0% +science uh I mean heresy doesn't really +have a whole lot lot of meaning in + + align:start position:0% +have a whole lot lot of meaning in + + + align:start position:0% +have a whole lot lot of meaning in +science if if there's a theory to be + + align:start position:0% +science if if there's a theory to be + + + align:start position:0% +science if if there's a theory to be +considered uh then it it should be + + align:start position:0% +considered uh then it it should be + + + align:start position:0% +considered uh then it it should be +considered but uh in in traditional uh + + align:start position:0% +considered but uh in in traditional uh + + + align:start position:0% +considered but uh in in traditional uh +religious Frameworks sometimes uh uh + + align:start position:0% +religious Frameworks sometimes uh uh + + + align:start position:0% +religious Frameworks sometimes uh uh +suggesting things such as Evolution or + + align:start position:0% +suggesting things such as Evolution or + + + align:start position:0% +suggesting things such as Evolution or +the similarity between humans and + + align:start position:0% +the similarity between humans and + + + align:start position:0% +the similarity between humans and +machines can be seen as a a heretical + + align:start position:0% +machines can be seen as a a heretical + + + align:start position:0% +machines can be seen as a a heretical +notion and he says if we allow heresy to + + align:start position:0% +notion and he says if we allow heresy to + + + align:start position:0% +notion and he says if we allow heresy to +to + + align:start position:0% +to + + + align:start position:0% +to +dictate what we study we're not going to + + align:start position:0% +dictate what we study we're not going to + + + align:start position:0% +dictate what we study we're not going to +get very far because you know we'll just + + align:start position:0% +get very far because you know we'll just + + + align:start position:0% +get very far because you know we'll just +have to take a lot off the table and say + + align:start position:0% +have to take a lot off the table and say + + + align:start position:0% +have to take a lot off the table and say +oh that's just you know it's heretical + + align:start position:0% +oh that's just you know it's heretical + + + align:start position:0% +oh that's just you know it's heretical +to consider that so yes Darwin uh + + align:start position:0% +to consider that so yes Darwin uh + + + align:start position:0% +to consider that so yes Darwin uh +Darwin's work by some uh by some uh + + align:start position:0% +Darwin's work by some uh by some uh + + + align:start position:0% +Darwin's work by some uh by some uh +thinkers was seen as heresy or or uh + + align:start position:0% +thinkers was seen as heresy or or uh + + + align:start position:0% +thinkers was seen as heresy or or uh +sort of irreligious and + + align:start position:0% +sort of irreligious and + + + align:start position:0% +sort of irreligious and +against um the whole concept of uh + + align:start position:0% +against um the whole concept of uh + + + align:start position:0% +against um the whole concept of uh +religion you you remember deia and Hume + + align:start position:0% +religion you you remember deia and Hume + + + align:start position:0% +religion you you remember deia and Hume +and what he said you know we should not + + align:start position:0% +and what he said you know we should not + + + align:start position:0% +and what he said you know we should not +consider these things we shouldn't even + + align:start position:0% +consider these things we shouldn't even + + + align:start position:0% +consider these things we shouldn't even +be talking about these questions because + + align:start position:0% +be talking about these questions because + + + align:start position:0% +be talking about these questions because +it's it's sacrilegious we should simply + + align:start position:0% +it's it's sacrilegious we should simply + + + align:start position:0% +it's it's sacrilegious we should simply +accept that the Creator made the world + + align:start position:0% +accept that the Creator made the world + + + align:start position:0% +accept that the Creator made the world +and the world is a is a wonderful + + align:start position:0% +and the world is a is a wonderful + + + align:start position:0% +and the world is a is a wonderful +marvelous place it's uh mysterious how + + align:start position:0% +marvelous place it's uh mysterious how + + + align:start position:0% +marvelous place it's uh mysterious how +it came into existence and to begin to + + align:start position:0% +it came into existence and to begin to + + + align:start position:0% +it came into existence and to begin to +reason about it and to think about it + + align:start position:0% +reason about it and to think about it + + + align:start position:0% +reason about it and to think about it +and to believe that we can understand it + + align:start position:0% +and to believe that we can understand it + + + align:start position:0% +and to believe that we can understand it +uh its Origins and principles is pushing + + align:start position:0% +uh its Origins and principles is pushing + + + align:start position:0% +uh its Origins and principles is pushing +us into the realm of the Creator and so + + align:start position:0% +us into the realm of the Creator and so + + + align:start position:0% +us into the realm of the Creator and so +um that's to me his point whereas you + + align:start position:0% +um that's to me his point whereas you + + + align:start position:0% +um that's to me his point whereas you +remember cleanthes is you + + align:start position:0% +remember cleanthes is you + + + align:start position:0% +remember cleanthes is you +know we can do it uh because these + + align:start position:0% +know we can do it uh because these + + + align:start position:0% +know we can do it uh because these +mechanical things that we find out about + + align:start position:0% +mechanical things that we find out about + + + align:start position:0% +mechanical things that we find out about +the the universe the world are things + + align:start position:0% +the the universe the world are things + + + align:start position:0% +the the universe the world are things +that uh simply + + align:start position:0% +that uh simply + + + align:start position:0% +that uh simply +prove the uh Glory of of God because + + align:start position:0% +prove the uh Glory of of God because + + + align:start position:0% +prove the uh Glory of of God because +they're so complex and so beautiful and + + align:start position:0% +they're so complex and so beautiful and + + + align:start position:0% +they're so complex and so beautiful and +so + + align:start position:0% +so + + + align:start position:0% +so +intricate so why not study the + + align:start position:0% +intricate so why not study the + + + align:start position:0% +intricate so why not study the +mechanical World in order to go from + + align:start position:0% +mechanical World in order to go from + + + align:start position:0% +mechanical World in order to go from +nature up to Nature's + + align:start position:0% +nature up to Nature's + + + align:start position:0% +nature up to Nature's +God and then finally we have felo who + + align:start position:0% +God and then finally we have felo who + + + align:start position:0% +God and then finally we have felo who +sort of plays The Devil's Advocate and + + align:start position:0% +sort of plays The Devil's Advocate and + + + align:start position:0% +sort of plays The Devil's Advocate and +he says well as long as we're looking at + + align:start position:0% +he says well as long as we're looking at + + + align:start position:0% +he says well as long as we're looking at +this uh beautiful wonderful place uh + + align:start position:0% +this uh beautiful wonderful place uh + + + align:start position:0% +this uh beautiful wonderful place uh +let's note that it's not exactly as + + align:start position:0% +let's note that it's not exactly as + + + align:start position:0% +let's note that it's not exactly as +perfect as uh an he thinks it is uh + + align:start position:0% +perfect as uh an he thinks it is uh + + + align:start position:0% +perfect as uh an he thinks it is uh +things survive yes but just barely and + + align:start position:0% +things survive yes but just barely and + + + align:start position:0% +things survive yes but just barely and +there's a great deal of suffering and a + + align:start position:0% +there's a great deal of suffering and a + + + align:start position:0% +there's a great deal of suffering and a +lot of catastrophes and it's not all + + align:start position:0% +lot of catastrophes and it's not all + + + align:start position:0% +lot of catastrophes and it's not all +made in any sense uh of of the word + + align:start position:0% +made in any sense uh of of the word + + + align:start position:0% +made in any sense uh of of the word +Perfection that everybody would agree on + + align:start position:0% +Perfection that everybody would agree on + + + align:start position:0% +Perfection that everybody would agree on +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so so that's the uh that's kind of the + + align:start position:0% +so so that's the uh that's kind of the + + + align:start position:0% +so so that's the uh that's kind of the +entree into this work he wants to weer + + align:start position:0% +entree into this work he wants to weer + + + align:start position:0% +entree into this work he wants to weer +wants to talk about humans and + + align:start position:0% +wants to talk about humans and + + + align:start position:0% +wants to talk about humans and +machines and he wants wants to talk + + align:start position:0% +machines and he wants wants to talk + + + align:start position:0% +machines and he wants wants to talk +about some of the ways in which they're + + align:start position:0% +about some of the ways in which they're + + + align:start position:0% +about some of the ways in which they're +parallel and to find ways in which we + + align:start position:0% +parallel and to find ways in which we + + + align:start position:0% +parallel and to find ways in which we +can learn from the two regimes by + + align:start position:0% +can learn from the two regimes by + + + align:start position:0% +can learn from the two regimes by +comparing them and studying them so uh + + align:start position:0% +comparing them and studying them so uh + + + align:start position:0% +comparing them and studying them so uh +that's his uh that's his his proposition + + align:start position:0% +that's his uh that's his his proposition + + + align:start position:0% +that's his uh that's his his proposition +but he has a lot of warnings along the + + align:start position:0% +but he has a lot of warnings along the + + + align:start position:0% +but he has a lot of warnings along the +way so this is not just to say oh + + align:start position:0% +way so this is not just to say oh + + + align:start position:0% +way so this is not just to say oh +machines are these wonderful devices and + + align:start position:0% +machines are these wonderful devices and + + + align:start position:0% +machines are these wonderful devices and +the more we have the the better it is + + align:start position:0% +the more we have the the better it is + + + align:start position:0% +the more we have the the better it is +and we should just + + align:start position:0% +and we should just + + + align:start position:0% +and we should just +continue uh without worry uh he's he's + + align:start position:0% +continue uh without worry uh he's he's + + + align:start position:0% +continue uh without worry uh he's he's +actually looking at the other side and + + align:start position:0% +actually looking at the other side and + + + align:start position:0% +actually looking at the other side and +saying + + align:start position:0% +saying + + + align:start position:0% +saying +well yes our machines are incredible + + align:start position:0% +well yes our machines are incredible + + + align:start position:0% +well yes our machines are incredible +creations and they have made it possible + + align:start position:0% +creations and they have made it possible + + + align:start position:0% +creations and they have made it possible +for us to survive but we have to be + + align:start position:0% +for us to survive but we have to be + + + align:start position:0% +for us to survive but we have to be +aware that they need they need to be + + align:start position:0% +aware that they need they need to be + + + align:start position:0% +aware that they need they need to be +controlled we need to understand them we + + align:start position:0% +controlled we need to understand them we + + + align:start position:0% +controlled we need to understand them we +have to understand their impacts and we + + align:start position:0% +have to understand their impacts and we + + + align:start position:0% +have to understand their impacts and we +can't just expect to keep using them + + align:start position:0% +can't just expect to keep using them + + + align:start position:0% +can't just expect to keep using them +without thinking that uh you know there + + align:start position:0% +without thinking that uh you know there + + + align:start position:0% +without thinking that uh you know there +going to be some costs there are costs + + align:start position:0% +going to be some costs there are costs + + + align:start position:0% +going to be some costs there are costs +and that's what he's + + align:start position:0% +and that's what he's + + + align:start position:0% +and that's what he's +uh okay so the three points U as Laur + + align:start position:0% +uh okay so the three points U as Laur + + + align:start position:0% +uh okay so the three points U as Laur +mentioned uh machines that + + align:start position:0% +mentioned uh machines that + + + align:start position:0% +mentioned uh machines that +learn machines that reproduce themselves + + align:start position:0% +learn machines that reproduce themselves + + + align:start position:0% +learn machines that reproduce themselves +are two + + align:start position:0% +are two + + + align:start position:0% +are two +concepts and uh machines that perform + + align:start position:0% +concepts and uh machines that perform + + + align:start position:0% +concepts and uh machines that perform +coordinately with man these are his key + + align:start position:0% +coordinately with man these are his key + + + align:start position:0% +coordinately with man these are his key +points of uh uh + + align:start position:0% +points of uh uh + + + align:start position:0% +points of uh uh +discussion what does learning imply in + + align:start position:0% +discussion what does learning imply in + + + align:start position:0% +discussion what does learning imply in +the way we usually use the + + align:start position:0% +the way we usually use the + + + align:start position:0% +the way we usually use the +word in terms of uh + + align:start position:0% +word in terms of uh + + + align:start position:0% +word in terms of uh +mental + + align:start position:0% + + + + align:start position:0% + +activity I mean don't we normally think + + align:start position:0% +activity I mean don't we normally think + + + align:start position:0% +activity I mean don't we normally think +of learning as some kind of mental + + align:start position:0% +of learning as some kind of mental + + + align:start position:0% +of learning as some kind of mental +activity certainly in in the case of the + + align:start position:0% +activity certainly in in the case of the + + + align:start position:0% +activity certainly in in the case of the +individual don't we I mean you're + + align:start position:0% +individual don't we I mean you're + + + align:start position:0% +individual don't we I mean you're +learning you're taking 1801 or 801 or + + align:start position:0% +learning you're taking 1801 or 801 or + + + align:start position:0% +learning you're taking 1801 or 801 or +802 or whatever you're taking uh I mean + + align:start position:0% +802 or whatever you're taking uh I mean + + + align:start position:0% +802 or whatever you're taking uh I mean +your learning is up here isn't it + + align:start position:0% +your learning is up here isn't it + + + align:start position:0% +your learning is up here isn't it +so what kind of stretch is it to say + + align:start position:0% +so what kind of stretch is it to say + + + align:start position:0% +so what kind of stretch is it to say +that you know there's this thing called + + align:start position:0% +that you know there's this thing called + + + align:start position:0% +that you know there's this thing called +philogenetic + + align:start position:0% +philogenetic + + + align:start position:0% +philogenetic +learning I think maybe he's referring to + + align:start position:0% +learning I think maybe he's referring to + + + align:start position:0% +learning I think maybe he's referring to +the type of learning um where like the + + align:start position:0% +the type of learning um where like the + + + align:start position:0% +the type of learning um where like the +knowledge is taken on persists in to + + align:start position:0% +knowledge is taken on persists in to + + + align:start position:0% +knowledge is taken on persists in to +like future Generations because what we + + align:start position:0% +like future Generations because what we + + + align:start position:0% +like future Generations because what we +learn as individuals unless we somehow + + align:start position:0% +learn as individuals unless we somehow + + + align:start position:0% +learn as individuals unless we somehow +have an impact on society is kind of + + align:start position:0% +have an impact on society is kind of + + + align:start position:0% +have an impact on society is kind of +irrelevant because eventually if it's + + align:start position:0% +irrelevant because eventually if it's + + + align:start position:0% +irrelevant because eventually if it's +just in our minds we're going to die and + + align:start position:0% +just in our minds we're going to die and + + + align:start position:0% +just in our minds we're going to die and +there's going to be no like learning of + + align:start position:0% +there's going to be no like learning of + + + align:start position:0% +there's going to be no like learning of +the species so it's what we learn as a + + align:start position:0% +the species so it's what we learn as a + + + align:start position:0% +the species so it's what we learn as a +species and what we communicate to + + align:start position:0% +species and what we communicate to + + + align:start position:0% +species and what we communicate to +others and gets passed on I guess that + + align:start position:0% +others and gets passed on I guess that + + + align:start position:0% +others and gets passed on I guess that +he's talking about in the sense of like + + align:start position:0% +he's talking about in the sense of like + + + align:start position:0% +he's talking about in the sense of like +philogenetic learning okay there are a + + align:start position:0% +philogenetic learning okay there are a + + + align:start position:0% +philogenetic learning okay there are a +lot of parallels here that you're you're + + align:start position:0% +lot of parallels here that you're you're + + + align:start position:0% +lot of parallels here that you're you're +bringing up uh yes + + align:start position:0% +bringing up uh yes + + + align:start position:0% +bringing up uh yes +Craig like in like in a fum there's not + + align:start position:0% +Craig like in like in a fum there's not + + + align:start position:0% +Craig like in like in a fum there's not +one spe one entity that's learning it's + + align:start position:0% +one spe one entity that's learning it's + + + align:start position:0% +one spe one entity that's learning it's +kind of taken as a whole class kind of + + align:start position:0% +kind of taken as a whole class kind of + + + align:start position:0% +kind of taken as a whole class kind of +Shifting towards the towards new trend + + align:start position:0% +Shifting towards the towards new trend + + + align:start position:0% +Shifting towards the towards new trend +and so there's not there it's not like + + align:start position:0% +and so there's not there it's not like + + + align:start position:0% +and so there's not there it's not like +something's actually getting smarter + + align:start position:0% +something's actually getting smarter + + + align:start position:0% +something's actually getting smarter +it's just through trial and a that okay + + align:start position:0% +it's just through trial and a that okay + + + align:start position:0% +it's just through trial and a that okay +mutations are working better it sort of + + align:start position:0% +mutations are working better it sort of + + + align:start position:0% +mutations are working better it sort of +goes back to the ship metaphor you know + + align:start position:0% +goes back to the ship metaphor you know + + + align:start position:0% +goes back to the ship metaphor you know +somebody learned how to make a very + + align:start position:0% +somebody learned how to make a very + + + align:start position:0% +somebody learned how to make a very +complicated clipper ship that you know + + align:start position:0% +complicated clipper ship that you know + + + align:start position:0% +complicated clipper ship that you know +you can send out across the oceans and + + align:start position:0% +you can send out across the oceans and + + + align:start position:0% +you can send out across the oceans and +uh go off to + + align:start position:0% +uh go off to + + + align:start position:0% +uh go off to +wherever uh that learning process some + + align:start position:0% +wherever uh that learning process some + + + align:start position:0% +wherever uh that learning process some +how got + + align:start position:0% +how got + + + align:start position:0% +how got +expressed in the physical object of the + + align:start position:0% +expressed in the physical object of the + + + align:start position:0% +expressed in the physical object of the +ship the ship is a kind of a A Treatise + + align:start position:0% +ship the ship is a kind of a A Treatise + + + align:start position:0% +ship the ship is a kind of a A Treatise +if you + + align:start position:0% +if you + + + align:start position:0% +if you +will of based on the learning of many + + align:start position:0% +will of based on the learning of many + + + align:start position:0% +will of based on the learning of many +many different individuals that went + + align:start position:0% +many different individuals that went + + + align:start position:0% +many different individuals that went +into the creation of this this very + + align:start position:0% +into the creation of this this very + + + align:start position:0% +into the creation of this this very +complex + + align:start position:0% +complex + + + align:start position:0% +complex +organism Charles I think the learning + + align:start position:0% +organism Charles I think the learning + + + align:start position:0% +organism Charles I think the learning +that that he's referring to here has + + align:start position:0% +that that he's referring to here has + + + align:start position:0% +that that he's referring to here has +more to do with the learning of babies + + align:start position:0% +more to do with the learning of babies + + + align:start position:0% +more to do with the learning of babies +than the learning that we do in school + + align:start position:0% +than the learning that we do in school + + + align:start position:0% +than the learning that we do in school +like now like for babies just getting to + + align:start position:0% +like now like for babies just getting to + + + align:start position:0% +like now like for babies just getting to +know the world it's like they'll try + + align:start position:0% +know the world it's like they'll try + + + align:start position:0% +know the world it's like they'll try +something and like that's where the + + align:start position:0% +something and like that's where the + + + align:start position:0% +something and like that's where the +parents role is it's like if they do + + align:start position:0% +parents role is it's like if they do + + + align:start position:0% +parents role is it's like if they do +something that's they're not supposed to + + align:start position:0% +something that's they're not supposed to + + + align:start position:0% +something that's they're not supposed to +do then they get I guess they may get + + align:start position:0% +do then they get I guess they may get + + + align:start position:0% +do then they get I guess they may get +punished and then so they know by trial + + align:start position:0% +punished and then so they know by trial + + + align:start position:0% +punished and then so they know by trial +error what not to do and what you can do + + align:start position:0% +error what not to do and what you can do + + + align:start position:0% +error what not to do and what you can do +and so in terms of like a in terms of + + align:start position:0% +and so in terms of like a in terms of + + + align:start position:0% +and so in terms of like a in terms of +like a whole race or like whole species + + align:start position:0% +like a whole race or like whole species + + + align:start position:0% +like a whole race or like whole species +if you think about every single + + align:start position:0% +if you think about every single + + + align:start position:0% +if you think about every single +individual as a new idea then you have + + align:start position:0% +individual as a new idea then you have + + + align:start position:0% +individual as a new idea then you have +all these new ideas that like they're + + align:start position:0% +all these new ideas that like they're + + + align:start position:0% +all these new ideas that like they're +just trying to figure their way around + + align:start position:0% +just trying to figure their way around + + + align:start position:0% +just trying to figure their way around +the world and whichever new ideas don't + + align:start position:0% +the world and whichever new ideas don't + + + align:start position:0% +the world and whichever new ideas don't +work don't get passed on and the new + + align:start position:0% +work don't get passed on and the new + + + align:start position:0% +work don't get passed on and the new +ideas that do work become like become + + align:start position:0% +ideas that do work become like become + + + align:start position:0% +ideas that do work become like become +like just knowledge right like you know + + align:start position:0% +like just knowledge right like you know + + + align:start position:0% +like just knowledge right like you know +it's right and then so you follow it's + + align:start position:0% +it's right and then so you follow it's + + + align:start position:0% +it's right and then so you follow it's +kind of like science you try this it's + + align:start position:0% +kind of like science you try this it's + + + align:start position:0% +kind of like science you try this it's +not right you try this this is right + + align:start position:0% +not right you try this this is right + + + align:start position:0% +not right you try this this is right +then I take my next step further and the + + align:start position:0% +then I take my next step further and the + + + align:start position:0% +then I take my next step further and the +next step further in this sense would + + align:start position:0% +next step further in this sense would + + + align:start position:0% +next step further in this sense would +just be the yeah + + align:start position:0% +just be the yeah + + + align:start position:0% +just be the yeah +uh any other yes Devin we can raise the + + align:start position:0% +uh any other yes Devin we can raise the + + + align:start position:0% +uh any other yes Devin we can raise the +level of abstraction though and we can + + align:start position:0% +level of abstraction though and we can + + + align:start position:0% +level of abstraction though and we can +as in any field of engineering draw a + + align:start position:0% +as in any field of engineering draw a + + + align:start position:0% +as in any field of engineering draw a +black box around anything whether it be + + align:start position:0% +black box around anything whether it be + + + align:start position:0% +black box around anything whether it be +a human being or a society or whatever + + align:start position:0% +a human being or a society or whatever + + + align:start position:0% +a human being or a society or whatever +you want and you know there's that + + align:start position:0% +you want and you know there's that + + + align:start position:0% +you want and you know there's that +there's that adage that the definition + + align:start position:0% +there's that adage that the definition + + + align:start position:0% +there's that adage that the definition +of irrationality is continually doing + + align:start position:0% +of irrationality is continually doing + + + align:start position:0% +of irrationality is continually doing +the same thing expecting different + + align:start position:0% +the same thing expecting different + + + align:start position:0% +the same thing expecting different +results so when you think of something + + align:start position:0% +results so when you think of something + + + align:start position:0% +results so when you think of something +like a function which Maps a bunch of + + align:start position:0% +like a function which Maps a bunch of + + + align:start position:0% +like a function which Maps a bunch of +inputs to a bunch of outputs no matter + + align:start position:0% +inputs to a bunch of outputs no matter + + + align:start position:0% +inputs to a bunch of outputs no matter +what you do you always give the same + + align:start position:0% +what you do you always give the same + + + align:start position:0% +what you do you always give the same +it's always going to give you the same + + align:start position:0% +it's always going to give you the same + + + align:start position:0% +it's always going to give you the same +result but the difference in any kind of + + align:start position:0% +result but the difference in any kind of + + + align:start position:0% +result but the difference in any kind of +Learning System whether it be a film or + + align:start position:0% +Learning System whether it be a film or + + + align:start position:0% +Learning System whether it be a film or +an individual is that as you give it a + + align:start position:0% +an individual is that as you give it a + + + align:start position:0% +an individual is that as you give it a +Time series you know you throw all this + + align:start position:0% +Time series you know you throw all this + + + align:start position:0% +Time series you know you throw all this +data information experiences at it it + + align:start position:0% +data information experiences at it it + + + align:start position:0% +data information experiences at it it +will slowly fine-tune its performance + + align:start position:0% +will slowly fine-tune its performance + + + align:start position:0% +will slowly fine-tune its performance +over time so that the outputs will + + align:start position:0% +over time so that the outputs will + + + align:start position:0% +over time so that the outputs will +change and hopefully stabilize and + + align:start position:0% +change and hopefully stabilize and + + + align:start position:0% +change and hopefully stabilize and +that's where the learning comes in and I + + align:start position:0% +that's where the learning comes in and I + + + align:start position:0% +that's where the learning comes in and I +think what he's getting out there is + + align:start position:0% +think what he's getting out there is + + + align:start position:0% +think what he's getting out there is +that that same kind of idea of a black + + align:start position:0% +that that same kind of idea of a black + + + align:start position:0% +that that same kind of idea of a black +box with input and output where the + + align:start position:0% +box with input and output where the + + + align:start position:0% +box with input and output where the +output is being fine-tuned as a result + + align:start position:0% +output is being fine-tuned as a result + + + align:start position:0% +output is being fine-tuned as a result +of the the relationships between the + + align:start position:0% +of the the relationships between the + + + align:start position:0% +of the the relationships between the +inputs is a general idea it's not just + + align:start position:0% +inputs is a general idea it's not just + + + align:start position:0% +inputs is a general idea it's not just +about people and it it it scales + + align:start position:0% +about people and it it it scales + + + align:start position:0% +about people and it it it scales +infinitely well and that's one of the + + align:start position:0% +infinitely well and that's one of the + + + align:start position:0% +infinitely well and that's one of the +the remarkable things about cybernetics + + align:start position:0% +the remarkable things about cybernetics + + + align:start position:0% +the remarkable things about cybernetics +as a field yeah yeah well put yeah yeah + + align:start position:0% +as a field yeah yeah well put yeah yeah + + + align:start position:0% +as a field yeah yeah well put yeah yeah +there there's this this this process of + + align:start position:0% +there there's this this this process of + + + align:start position:0% +there there's this this this process of +learning that is iterative and all these + + align:start position:0% +learning that is iterative and all these + + + align:start position:0% +learning that is iterative and all these +iterative uh the the the power of + + align:start position:0% +iterative uh the the the power of + + + align:start position:0% +iterative uh the the the power of +darwinian natural selection as an idea + + align:start position:0% +darwinian natural selection as an idea + + + align:start position:0% +darwinian natural selection as an idea +is this constant con this concept of the + + align:start position:0% +is this constant con this concept of the + + + align:start position:0% +is this constant con this concept of the +constant input and output which in the + + align:start position:0% +constant input and output which in the + + + align:start position:0% +constant input and output which in the +case of an individual organism is simply + + align:start position:0% +case of an individual organism is simply + + + align:start position:0% +case of an individual organism is simply +uh + + align:start position:0% +uh + + + align:start position:0% +uh +reproduction reproduction passing on of + + align:start position:0% +reproduction reproduction passing on of + + + align:start position:0% +reproduction reproduction passing on of +uh certain kinds of uh traits remember + + align:start position:0% +uh certain kinds of uh traits remember + + + align:start position:0% +uh certain kinds of uh traits remember +Unity of type and also the fact that + + align:start position:0% +Unity of type and also the fact that + + + align:start position:0% +Unity of type and also the fact that +there is variation which these two facts + + align:start position:0% +there is variation which these two facts + + + align:start position:0% +there is variation which these two facts +uh uh weiner mentions in in the book as + + align:start position:0% +uh uh weiner mentions in in the book as + + + align:start position:0% +uh uh weiner mentions in in the book as +Salient points in evolution and so u in + + align:start position:0% +Salient points in evolution and so u in + + + align:start position:0% +Salient points in evolution and so u in +philogyny the expression of the learning + + align:start position:0% +philogyny the expression of the learning + + + align:start position:0% +philogyny the expression of the learning +takes what + + align:start position:0% + + + + align:start position:0% + +form + + align:start position:0% + + + + align:start position:0% + +well physical features of the organism I + + align:start position:0% +well physical features of the organism I + + + align:start position:0% +well physical features of the organism I +mean the uh the adaptability of uh say + + align:start position:0% +mean the uh the adaptability of uh say + + + align:start position:0% +mean the uh the adaptability of uh say +an organ an + + align:start position:0% +an organ an + + + align:start position:0% +an organ an +organism in terms of the eye eyesight I + + align:start position:0% +organism in terms of the eye eyesight I + + + align:start position:0% +organism in terms of the eye eyesight I +mean that's so when he when he's talking + + align:start position:0% +mean that's so when he when he's talking + + + align:start position:0% +mean that's so when he when he's talking +about phenetic learning he's really + + align:start position:0% +about phenetic learning he's really + + + align:start position:0% +about phenetic learning he's really +talking about that that kind of process + + align:start position:0% +talking about that that kind of process + + + align:start position:0% +talking about that that kind of process +that delivers a a a higher and higher + + align:start position:0% +that delivers a a a higher and higher + + + align:start position:0% +that delivers a a a higher and higher +functioning eye and its interaction with + + align:start position:0% +functioning eye and its interaction with + + + align:start position:0% +functioning eye and its interaction with +the environment becomes uh more and more + + align:start position:0% +the environment becomes uh more and more + + + align:start position:0% +the environment becomes uh more and more +refined and so it's a physical + + align:start position:0% +refined and so it's a physical + + + align:start position:0% +refined and so it's a physical +expression back to the ship it's it's an + + align:start position:0% +expression back to the ship it's it's an + + + align:start position:0% +expression back to the ship it's it's an +expression of of of physical + + align:start position:0% +expression of of of physical + + + align:start position:0% +expression of of of physical +interaction with + + align:start position:0% +interaction with + + + align:start position:0% +interaction with +environment in a a space a + + align:start position:0% +environment in a a space a + + + align:start position:0% +environment in a a space a +niche and higher higher levels of + + align:start position:0% +niche and higher higher levels of + + + align:start position:0% +niche and higher higher levels of +performance there would be in wier's + + align:start position:0% +performance there would be in wier's + + + align:start position:0% +performance there would be in wier's +terms philogenetic learning this is what + + align:start position:0% +terms philogenetic learning this is what + + + align:start position:0% +terms philogenetic learning this is what +delivers these complex organisms that + + align:start position:0% +delivers these complex organisms that + + + align:start position:0% +delivers these complex organisms that +are adapted to their + + align:start position:0% +are adapted to their + + + align:start position:0% +are adapted to their +environments okay so all this is based + + align:start position:0% +environments okay so all this is based + + + align:start position:0% +environments okay so all this is based +on this this kind of darwinian iteration + + align:start position:0% +on this this kind of darwinian iteration + + + align:start position:0% +on this this kind of darwinian iteration +process of U basically information out + + align:start position:0% +process of U basically information out + + + align:start position:0% +process of U basically information out +information in and information out um + + align:start position:0% +information in and information out um + + + align:start position:0% +information in and information out um +and a certain amount of change taking + + align:start position:0% +and a certain amount of change taking + + + align:start position:0% +and a certain amount of change taking +place and the new + + align:start position:0% +place and the new + + + align:start position:0% +place and the new +entity that has inherited the + + align:start position:0% +entity that has inherited the + + + align:start position:0% +entity that has inherited the +information of the last the parent + + align:start position:0% +information of the last the parent + + + align:start position:0% +information of the last the parent +entity either functions better uh or it + + align:start position:0% +entity either functions better uh or it + + + align:start position:0% +entity either functions better uh or it +doesn't but uh it's it's basically going + + align:start position:0% +doesn't but uh it's it's basically going + + + align:start position:0% +doesn't but uh it's it's basically going +to be + + align:start position:0% +to be + + + align:start position:0% +to be +tested each generation is going to be + + align:start position:0% +tested each generation is going to be + + + align:start position:0% +tested each generation is going to be +tested for the ability to uh survive and + + align:start position:0% +tested for the ability to uh survive and + + + align:start position:0% +tested for the ability to uh survive and +so this is a model that he's using for + + align:start position:0% +so this is a model that he's using for + + + align:start position:0% +so this is a model that he's using for +for uh machine learning too when he + + align:start position:0% +for uh machine learning too when he + + + align:start position:0% +for uh machine learning too when he +talks about machine + + align:start position:0% +talks about machine + + + align:start position:0% +talks about machine +learning and he talks about as or + + align:start position:0% +learning and he talks about as or + + + align:start position:0% +learning and he talks about as or +mentioned uh in terms of + + align:start position:0% +mentioned uh in terms of + + + align:start position:0% +mentioned uh in terms of +tic-tac-toe these little systems that uh + + align:start position:0% +tic-tac-toe these little systems that uh + + + align:start position:0% +tic-tac-toe these little systems that uh +can be uh played with a with a a + + align:start position:0% +can be uh played with a with a a + + + align:start position:0% +can be uh played with a with a a +computer and can actually be + + align:start position:0% +computer and can actually be + + + align:start position:0% +computer and can actually be +U uh subject to + + align:start position:0% +U uh subject to + + + align:start position:0% +U uh subject to +Improvement they get better + + align:start position:0% +Improvement they get better + + + align:start position:0% +Improvement they get better +and so there's a what he calls a + + align:start position:0% +and so there's a what he calls a + + + align:start position:0% +and so there's a what he calls a +Criterion of Merit that + + align:start position:0% +Criterion of Merit that + + + align:start position:0% +Criterion of Merit that +actually is a uh element in the + + align:start position:0% +actually is a uh element in the + + + align:start position:0% +actually is a uh element in the +selection process and as this uh + + align:start position:0% +selection process and as this uh + + + align:start position:0% +selection process and as this uh +improves it becomes uh the the the form + + align:start position:0% +improves it becomes uh the the the form + + + align:start position:0% +improves it becomes uh the the the form +that gets uh + + align:start position:0% +that gets uh + + + align:start position:0% +that gets uh +transmitted and so this this sort of + + align:start position:0% +transmitted and so this this sort of + + + align:start position:0% +transmitted and so this this sort of +process is uh is is + + align:start position:0% +process is uh is is + + + align:start position:0% +process is uh is is +key all right + + align:start position:0% + + + + align:start position:0% + +so all right and he also brings up this + + align:start position:0% +so all right and he also brings up this + + + align:start position:0% +so all right and he also brings up this +question of uh how + + align:start position:0% +question of uh how + + + align:start position:0% +question of uh how +different + + align:start position:0% +different + + + align:start position:0% +different +are bio our biological or organisms and + + align:start position:0% +are bio our biological or organisms and + + + align:start position:0% +are bio our biological or organisms and +uh mechanical + + align:start position:0% +uh mechanical + + + align:start position:0% +uh mechanical +processes and his uh one of his one of + + align:start position:0% +processes and his uh one of his one of + + + align:start position:0% +processes and his uh one of his one of +his major points is that U at the level + + align:start position:0% +his major points is that U at the level + + + align:start position:0% +his major points is that U at the level +of reproduction + + align:start position:0% +of reproduction + + + align:start position:0% +of reproduction +what is human reproduction what is any + + align:start position:0% +what is human reproduction what is any + + + align:start position:0% +what is human reproduction what is any +kind of biological + + align:start position:0% +kind of biological + + + align:start position:0% +kind of biological +reproduction it's I mean of course he + + align:start position:0% +reproduction it's I mean of course he + + + align:start position:0% +reproduction it's I mean of course he +knows a lot more you can see you know + + align:start position:0% +knows a lot more you can see you know + + + align:start position:0% +knows a lot more you can see you know +what's happened mle has been there you + + align:start position:0% +what's happened mle has been there you + + + align:start position:0% +what's happened mle has been there you +know and and you know he's way down the + + align:start position:0% +know and and you know he's way down the + + + align:start position:0% +know and and you know he's way down the +line now here from + + align:start position:0% +line now here from + + + align:start position:0% +line now here from +Darwin uh it's well known that uh + + align:start position:0% +Darwin uh it's well known that uh + + + align:start position:0% +Darwin uh it's well known that uh +there's a whole process taking place + + align:start position:0% +there's a whole process taking place + + + align:start position:0% +there's a whole process taking place +here and for all intents and purposes + + align:start position:0% +here and for all intents and purposes + + + align:start position:0% +here and for all intents and purposes +it's primarily a process of uh pattern + + align:start position:0% +it's primarily a process of uh pattern + + + align:start position:0% +it's primarily a process of uh pattern +and pattern superimposition on other + + align:start position:0% +and pattern superimposition on other + + + align:start position:0% +and pattern superimposition on other +uh and and the creation of new patterns + + align:start position:0% +uh and and the creation of new patterns + + + align:start position:0% +uh and and the creation of new patterns +from old patterns so he says here on + + align:start position:0% +from old patterns so he says here on + + + align:start position:0% +from old patterns so he says here on +page uh + + align:start position:0% +page uh + + + align:start position:0% +page uh +28 behind all this fantastically complex + + align:start position:0% +28 behind all this fantastically complex + + + align:start position:0% +28 behind all this fantastically complex +concatenation of processes he's talking + + align:start position:0% +concatenation of processes he's talking + + + align:start position:0% +concatenation of processes he's talking +about biological reproduction here lies + + align:start position:0% +about biological reproduction here lies + + + align:start position:0% +about biological reproduction here lies +one very simple fact that in the + + align:start position:0% +one very simple fact that in the + + + align:start position:0% +one very simple fact that in the +presence of a suitable nutritive + + align:start position:0% +presence of a suitable nutritive + + + align:start position:0% +presence of a suitable nutritive +nutritive uh medium of nucleic acids and + + align:start position:0% +nutritive uh medium of nucleic acids and + + + align:start position:0% +nutritive uh medium of nucleic acids and +amino acids a molecule of a gene + + align:start position:0% +amino acids a molecule of a gene + + + align:start position:0% +amino acids a molecule of a gene +consisting itself of a high specific + + align:start position:0% +consisting itself of a high specific + + + align:start position:0% +consisting itself of a high specific +combination of amino acids and nucleic + + align:start position:0% +combination of amino acids and nucleic + + + align:start position:0% +combination of amino acids and nucleic +acids can cause the medium to lay itself + + align:start position:0% +acids can cause the medium to lay itself + + + align:start position:0% +acids can cause the medium to lay itself +down into other molecules which either + + align:start position:0% +down into other molecules which either + + + align:start position:0% +down into other molecules which either +are molecules of the same gene or of + + align:start position:0% +are molecules of the same gene or of + + + align:start position:0% +are molecules of the same gene or of +other genes differing from it by + + align:start position:0% +other genes differing from it by + + + align:start position:0% +other genes differing from it by +relatively slight + + align:start position:0% +relatively slight + + + align:start position:0% +relatively slight +variations so there's a basically a + + align:start position:0% +variations so there's a basically a + + + align:start position:0% +variations so there's a basically a +pattern uh process of repetition and + + align:start position:0% +pattern uh process of repetition and + + + align:start position:0% +pattern uh process of repetition and +replication at the core at the center of + + align:start position:0% +replication at the core at the center of + + + align:start position:0% +replication at the core at the center of +biological + + align:start position:0% +biological + + + align:start position:0% +biological +reproduction what do you think think of + + align:start position:0% + + + + align:start position:0% + +that sound like + + align:start position:0% +that sound like + + + align:start position:0% +that sound like +machine well well you know there are + + align:start position:0% +machine well well you know there are + + + align:start position:0% +machine well well you know there are +other things in the book that make us + + align:start position:0% +other things in the book that make us + + + align:start position:0% +other things in the book that make us +you know sound like uh we should be + + align:start position:0% +you know sound like uh we should be + + + align:start position:0% +you know sound like uh we should be +Beyond machines too but you know at at + + align:start position:0% +Beyond machines too but you know at at + + + align:start position:0% +Beyond machines too but you know at at +the heart at the heart you know we we + + align:start position:0% +the heart at the heart you know we we + + + align:start position:0% +the heart at the heart you know we we +again this is in the spirit of Norbert + + align:start position:0% +again this is in the spirit of Norbert + + + align:start position:0% +again this is in the spirit of Norbert +weiner we we need to put aside our our + + align:start position:0% +weiner we we need to put aside our our + + + align:start position:0% +weiner we we need to put aside our our +biases and our and you know if we really + + align:start position:0% +biases and our and you know if we really + + + align:start position:0% +biases and our and you know if we really +want to understand something it's not to + + align:start position:0% +want to understand something it's not to + + + align:start position:0% +want to understand something it's not to +say that that's + + align:start position:0% +say that that's + + + align:start position:0% +say that that's +all but at least understand that at at + + align:start position:0% +all but at least understand that at at + + + align:start position:0% +all but at least understand that at at +the core that you know there are certain + + align:start position:0% +the core that you know there are certain + + + align:start position:0% +the core that you know there are certain +kinds of patterns and + + align:start position:0% + + + + align:start position:0% + +similarities uh I mean we could say wow + + align:start position:0% +similarities uh I mean we could say wow + + + align:start position:0% +similarities uh I mean we could say wow +you know this is this is making us into + + align:start position:0% +you know this is this is making us into + + + align:start position:0% +you know this is this is making us into +let's let's just forget about this field + + align:start position:0% +let's let's just forget about this field + + + align:start position:0% +let's let's just forget about this field +go away and you know make better cars or + + align:start position:0% +go away and you know make better cars or + + + align:start position:0% +go away and you know make better cars or +something you know but here we are I + + align:start position:0% +something you know but here we are I + + + align:start position:0% +something you know but here we are I +don't I've never understood every time + + align:start position:0% +don't I've never understood every time + + + align:start position:0% +don't I've never understood every time +the seg I don't what's the problem with + + align:start position:0% +the seg I don't what's the problem with + + + align:start position:0% +the seg I don't what's the problem with +being a machine what's the where's the + + align:start position:0% +being a machine what's the where's the + + + align:start position:0% +being a machine what's the where's the +where's the real breakdown I mean I + + align:start position:0% +where's the real breakdown I mean I + + + align:start position:0% +where's the real breakdown I mean I +guess I'm pretty naive in that I didn't + + align:start position:0% +guess I'm pretty naive in that I didn't + + + align:start position:0% +guess I'm pretty naive in that I didn't +grow up in a religious household and I + + align:start position:0% +grow up in a religious household and I + + + align:start position:0% +grow up in a religious household and I +wasn't surrounded by religious people so + + align:start position:0% +wasn't surrounded by religious people so + + + align:start position:0% +wasn't surrounded by religious people so +for me it's hard for me to grasp exactly + + align:start position:0% +for me it's hard for me to grasp exactly + + + align:start position:0% +for me it's hard for me to grasp exactly +what what that influence means because + + align:start position:0% +what what that influence means because + + + align:start position:0% +what what that influence means because +if you're a machine you know there's + + align:start position:0% +if you're a machine you know there's + + + align:start position:0% +if you're a machine you know there's +still the human use of human beings + + align:start position:0% +still the human use of human beings + + + align:start position:0% +still the human use of human beings +you're not being devalued in any way I + + align:start position:0% +you're not being devalued in any way I + + + align:start position:0% +you're not being devalued in any way I +don't I don't see what I'm just curious + + align:start position:0% +don't I don't see what I'm just curious + + + align:start position:0% +don't I don't see what I'm just curious +to get other people's perspective on + + align:start position:0% +to get other people's perspective on + + + align:start position:0% +to get other people's perspective on +that good question good question well I + + align:start position:0% +that good question good question well I + + + align:start position:0% +that good question good question well I +think that um it's like the machines + + align:start position:0% +think that um it's like the machines + + + align:start position:0% +think that um it's like the machines +that we've all grown up knowing don't + + align:start position:0% +that we've all grown up knowing don't + + + align:start position:0% +that we've all grown up knowing don't +have a mind of their own and so they're + + align:start position:0% +have a mind of their own and so they're + + + align:start position:0% +have a mind of their own and so they're +mindless and like maybe if you can say + + align:start position:0% +mindless and like maybe if you can say + + + align:start position:0% +mindless and like maybe if you can say +that oh they function and they come + + align:start position:0% +that oh they function and they come + + + align:start position:0% +that oh they function and they come +alive but then if you say that they're + + align:start position:0% +alive but then if you say that they're + + + align:start position:0% +alive but then if you say that they're +alive their life is basically + + align:start position:0% +alive their life is basically + + + align:start position:0% +alive their life is basically +meaningless because it's it's hasn't got + + align:start position:0% +meaningless because it's it's hasn't got + + + align:start position:0% +meaningless because it's it's hasn't got +any freedom of its own and so like just + + align:start position:0% +any freedom of its own and so like just + + + align:start position:0% +any freedom of its own and so like just +I think it's just growing up with + + align:start position:0% +I think it's just growing up with + + + align:start position:0% +I think it's just growing up with +technology like that and you are afraid + + align:start position:0% +technology like that and you are afraid + + + align:start position:0% +technology like that and you are afraid +that if your life is just like that of a + + align:start position:0% +that if your life is just like that of a + + + align:start position:0% +that if your life is just like that of a +machine that we have today which are our + + align:start position:0% +machine that we have today which are our + + + align:start position:0% +machine that we have today which are our +machines are rather rudimentary then + + align:start position:0% +machines are rather rudimentary then + + + align:start position:0% +machines are rather rudimentary then +like our lives would just be meaningless + + align:start position:0% +like our lives would just be meaningless + + + align:start position:0% +like our lives would just be meaningless +and that's a that's like a pretty + + align:start position:0% +and that's a that's like a pretty + + + align:start position:0% +and that's a that's like a pretty +terrifying concept to Grass interesting + + align:start position:0% +terrifying concept to Grass interesting + + + align:start position:0% +terrifying concept to Grass interesting +good points yeah okay uh kind of going + + align:start position:0% +good points yeah okay uh kind of going + + + align:start position:0% +good points yeah okay uh kind of going +off that I think uh machines lack + + align:start position:0% +off that I think uh machines lack + + + align:start position:0% +off that I think uh machines lack +the like element of life I mean that's + + align:start position:0% +the like element of life I mean that's + + + align:start position:0% +the like element of life I mean that's +not obviously not a great way of saying + + align:start position:0% +not obviously not a great way of saying + + + align:start position:0% +not obviously not a great way of saying +it but they don't have + + align:start position:0% +it but they don't have + + + align:start position:0% +it but they don't have +uh they they're artificial there + + align:start position:0% +uh they they're artificial there + + + align:start position:0% +uh they they're artificial there +everything I in an ideal machine would + + align:start position:0% +everything I in an ideal machine would + + + align:start position:0% +everything I in an ideal machine would +give you this response all the time when + + align:start position:0% +give you this response all the time when + + + align:start position:0% +give you this response all the time when +you put this stimulus or give it this + + align:start position:0% +you put this stimulus or give it this + + + align:start position:0% +you put this stimulus or give it this +question or whatever it's going to give + + align:start position:0% +question or whatever it's going to give + + + align:start position:0% +question or whatever it's going to give +you the same thing each time for the + + align:start position:0% +you the same thing each time for the + + + align:start position:0% +you the same thing each time for the +same uh stimulus whereas a human I I say + + align:start position:0% +same uh stimulus whereas a human I I say + + + align:start position:0% +same uh stimulus whereas a human I I say +hi today you say hi tomorrow you say hey + + align:start position:0% +hi today you say hi tomorrow you say hey + + + align:start position:0% +hi today you say hi tomorrow you say hey +the next day you say hello it's got that + + align:start position:0% +the next day you say hello it's got that + + + align:start position:0% +the next day you say hello it's got that +degree of variability or one day if + + align:start position:0% +degree of variability or one day if + + + align:start position:0% +degree of variability or one day if +you're pissed off of you might ignore me + + align:start position:0% +you're pissed off of you might ignore me + + + align:start position:0% +you're pissed off of you might ignore me +and just blow me off completely and I + + align:start position:0% +and just blow me off completely and I + + + align:start position:0% +and just blow me off completely and I +think uh the idea of being a machine and + + align:start position:0% +think uh the idea of being a machine and + + + align:start position:0% +think uh the idea of being a machine and +taking away that Humanity of it is + + align:start position:0% +taking away that Humanity of it is + + + align:start position:0% +taking away that Humanity of it is +distasteful some people and that's why I + + align:start position:0% +distasteful some people and that's why I + + + align:start position:0% +distasteful some people and that's why I +don't think it necessarily has to do + + align:start position:0% +don't think it necessarily has to do + + + align:start position:0% +don't think it necessarily has to do +with religion it's just personally I + + align:start position:0% +with religion it's just personally I + + + align:start position:0% +with religion it's just personally I +wouldn't want to be so just set stone so + + align:start position:0% +wouldn't want to be so just set stone so + + + align:start position:0% +wouldn't want to be so just set stone so +artificial so you do this I do this you + + align:start position:0% +artificial so you do this I do this you + + + align:start position:0% +artificial so you do this I do this you +do this I do this you do this I do this + + align:start position:0% +do this I do this you do this I do this + + + align:start position:0% +do this I do this you do this I do this +I'd rather have I think it's more + + align:start position:0% +I'd rather have I think it's more + + + align:start position:0% +I'd rather have I think it's more +appealing to have the degree of + + align:start position:0% +appealing to have the degree of + + + align:start position:0% +appealing to have the degree of +variability rather than just uh I'm just + + align:start position:0% +variability rather than just uh I'm just + + + align:start position:0% +variability rather than just uh I'm just +going through my program this stimulus + + align:start position:0% +going through my program this stimulus + + + align:start position:0% +going through my program this stimulus +means I have these three options this + + align:start position:0% +means I have these three options this + + + align:start position:0% +means I have these three options this +one is this this one is this this I'll + + align:start position:0% +one is this this one is this this I'll + + + align:start position:0% +one is this this one is this this I'll +select this one rather than being able + + align:start position:0% +select this one rather than being able + + + align:start position:0% +select this one rather than being able +to do whatever I want with it good point + + align:start position:0% +to do whatever I want with it good point + + + align:start position:0% +to do whatever I want with it good point +yeah I think the problem religious + + align:start position:0% +yeah I think the problem religious + + + align:start position:0% +yeah I think the problem religious +people have with it is that essentially + + align:start position:0% +people have with it is that essentially + + + align:start position:0% +people have with it is that essentially +I think a lot of religions say that you + + align:start position:0% +I think a lot of religions say that you + + + align:start position:0% +I think a lot of religions say that you +know humans are not just a body they're + + align:start position:0% +know humans are not just a body they're + + + align:start position:0% +know humans are not just a body they're +body and a soul and when you can reduce + + align:start position:0% +body and a soul and when you can reduce + + + align:start position:0% +body and a soul and when you can reduce +a human down into all these little + + align:start position:0% +a human down into all these little + + + align:start position:0% +a human down into all these little +mechanical bits and that's all that it + + align:start position:0% +mechanical bits and that's all that it + + + align:start position:0% +mechanical bits and that's all that it +is it's kind of saying that humans don't + + align:start position:0% +is it's kind of saying that humans don't + + + align:start position:0% +is it's kind of saying that humans don't +have that extra spiritual bit that we're + + align:start position:0% +have that extra spiritual bit that we're + + + align:start position:0% +have that extra spiritual bit that we're +just purely machine and I think that's + + align:start position:0% +just purely machine and I think that's + + + align:start position:0% +just purely machine and I think that's +what starts to bother people because + + align:start position:0% +what starts to bother people because + + + align:start position:0% +what starts to bother people because +then they say do we have a conscience or + + align:start position:0% +then they say do we have a conscience or + + + align:start position:0% +then they say do we have a conscience or +is it all mechanical is there are we + + align:start position:0% +is it all mechanical is there are we + + + align:start position:0% +is it all mechanical is there are we +something else + + align:start position:0% +something else + + + align:start position:0% +something else +like is there meaning in life as opposed + + align:start position:0% +like is there meaning in life as opposed + + + align:start position:0% +like is there meaning in life as opposed +to is it just some kind of iterative uh + + align:start position:0% +to is it just some kind of iterative uh + + + align:start position:0% +to is it just some kind of iterative uh +replicant uh process that uh has no + + align:start position:0% +replicant uh process that uh has no + + + align:start position:0% +replicant uh process that uh has no +deeper + + align:start position:0% +deeper + + + align:start position:0% +deeper +meaning and humans of + + align:start position:0% +meaning and humans of + + + align:start position:0% +meaning and humans of +course + + align:start position:0% +course + + + align:start position:0% +course +they thirst for some you know for + + align:start position:0% +they thirst for some you know for + + + align:start position:0% +they thirst for some you know for +meaning in their lives + + align:start position:0% +meaning in their lives + + + align:start position:0% +meaning in their lives +but you know there may be ways in which + + align:start position:0% +but you know there may be ways in which + + + align:start position:0% +but you know there may be ways in which +you know these are I mean to say that at + + align:start position:0% +you know these are I mean to say that at + + + align:start position:0% +you know these are I mean to say that at +the core things are + + align:start position:0% +the core things are + + + align:start position:0% +the core things are +mechanical is not necessarily to take + + align:start position:0% +mechanical is not necessarily to take + + + align:start position:0% +mechanical is not necessarily to take +away you know the the ability of people + + align:start position:0% +away you know the the ability of people + + + align:start position:0% +away you know the the ability of people +to find Value in their their lives and + + align:start position:0% +to find Value in their their lives and + + + align:start position:0% +to find Value in their their lives and +you know we're very complicated + + align:start position:0% +you know we're very complicated + + + align:start position:0% +you know we're very complicated +entities but at the core here as he's + + align:start position:0% +entities but at the core here as he's + + + align:start position:0% +entities but at the core here as he's +pointing out there there's some kind of + + align:start position:0% +pointing out there there's some kind of + + + align:start position:0% +pointing out there there's some kind of +mechanical process that basically shows + + align:start position:0% +mechanical process that basically shows + + + align:start position:0% +mechanical process that basically shows +that you know there are a lot of + + align:start position:0% +that you know there are a lot of + + + align:start position:0% +that you know there are a lot of +parallels at certain levels between + + align:start position:0% +parallels at certain levels between + + + align:start position:0% +parallels at certain levels between +humans and + + align:start position:0% +humans and + + + align:start position:0% +humans and +machines and what is the purpose of + + align:start position:0% +machines and what is the purpose of + + + align:start position:0% +machines and what is the purpose of +trying to search for + + align:start position:0% +trying to search for + + + align:start position:0% +trying to search for +this the cyberneticist says well we can + + align:start position:0% +this the cyberneticist says well we can + + + align:start position:0% +this the cyberneticist says well we can +learn from this process we can learn + + align:start position:0% +learn from this process we can learn + + + align:start position:0% +learn from this process we can learn +something about all kinds of + + align:start position:0% +something about all kinds of + + + align:start position:0% +something about all kinds of +phenomena in the physical + + align:start position:0% +phenomena in the physical + + + align:start position:0% +phenomena in the physical +world and we can learn things about + + align:start position:0% +world and we can learn things about + + + align:start position:0% +world and we can learn things about +humans too so there's the knowledge gen + + align:start position:0% +humans too so there's the knowledge gen + + + align:start position:0% +humans too so there's the knowledge gen +the person in search of knowledge wants + + align:start position:0% +the person in search of knowledge wants + + + align:start position:0% +the person in search of knowledge wants +to understand more + + align:start position:0% +to understand more + + + align:start position:0% +to understand more +deeply the mechanical processes at the + + align:start position:0% +deeply the mechanical processes at the + + + align:start position:0% +deeply the mechanical processes at the +heart of all phenomena whether + + align:start position:0% +heart of all phenomena whether + + + align:start position:0% +heart of all phenomena whether +mechanical machines or + + align:start position:0% +mechanical machines or + + + align:start position:0% +mechanical machines or +humans but then a lot of it depends as + + align:start position:0% +humans but then a lot of it depends as + + + align:start position:0% +humans but then a lot of it depends as +Dev says how how far you want to go in + + align:start position:0% +Dev says how how far you want to go in + + + align:start position:0% +Dev says how how far you want to go in +the + + align:start position:0% +the + + + align:start position:0% +the +abstraction and where you want to take + + align:start position:0% +abstraction and where you want to take + + + align:start position:0% +abstraction and where you want to take +it + + align:start position:0% +it + + + align:start position:0% +it +but uh certainly he's for his purposes + + align:start position:0% +but uh certainly he's for his purposes + + + align:start position:0% +but uh certainly he's for his purposes +he's laying down something some very + + align:start position:0% +he's laying down something some very + + + align:start position:0% +he's laying down something some very +important principles here other thoughts + + align:start position:0% +important principles here other thoughts + + + align:start position:0% +important principles here other thoughts +on + + align:start position:0% +on + + + align:start position:0% +on +this yeah so yeah kind of along with was + + align:start position:0% +this yeah so yeah kind of along with was + + + align:start position:0% +this yeah so yeah kind of along with was +saying and like you were saying how + + align:start position:0% +saying and like you were saying how + + + align:start position:0% +saying and like you were saying how +people have sort of like people have a + + align:start position:0% +people have sort of like people have a + + + align:start position:0% +people have sort of like people have a +thirst for a finding a meaning of life + + align:start position:0% +thirst for a finding a meaning of life + + + align:start position:0% +thirst for a finding a meaning of life +finding a meaning to their lives and I + + align:start position:0% +finding a meaning to their lives and I + + + align:start position:0% +finding a meaning to their lives and I +think that like with computers the thing + + align:start position:0% +think that like with computers the thing + + + align:start position:0% +think that like with computers the thing +is that we know everything about them + + align:start position:0% +is that we know everything about them + + + align:start position:0% +is that we know everything about them +they're so complex so beautiful in terms + + align:start position:0% +they're so complex so beautiful in terms + + + align:start position:0% +they're so complex so beautiful in terms +of what we have created so far but like + + align:start position:0% +of what we have created so far but like + + + align:start position:0% +of what we have created so far but like +we know every single thing about them + + align:start position:0% +we know every single thing about them + + + align:start position:0% +we know every single thing about them +and there's no there's no magic in there + + align:start position:0% +and there's no there's no magic in there + + + align:start position:0% +and there's no there's no magic in there +like if we found a computer and we + + align:start position:0% +like if we found a computer and we + + + align:start position:0% +like if we found a computer and we +learned how to use it without + + align:start position:0% +learned how to use it without + + + align:start position:0% +learned how to use it without +understanding how it worked there would + + align:start position:0% +understanding how it worked there would + + + align:start position:0% +understanding how it worked there would +be some some sense of magic in there and + + align:start position:0% +be some some sense of magic in there and + + + align:start position:0% +be some some sense of magic in there and +I think it's that sense that like the + + align:start position:0% +I think it's that sense that like the + + + align:start position:0% +I think it's that sense that like the +more science develops like the more we + + align:start position:0% +more science develops like the more we + + + align:start position:0% +more science develops like the more we +know about how we work the more the L + + align:start position:0% +know about how we work the more the L + + + align:start position:0% +know about how we work the more the L +less like un the less mystery there is + + align:start position:0% +less like un the less mystery there is + + + align:start position:0% +less like un the less mystery there is +in there and like since ancient times + + align:start position:0% +in there and like since ancient times + + + align:start position:0% +in there and like since ancient times +people have been kind of relying on this + + align:start position:0% +people have been kind of relying on this + + + align:start position:0% +people have been kind of relying on this +mystery there like this mysterious and + + align:start position:0% +mystery there like this mysterious and + + + align:start position:0% +mystery there like this mysterious and +unknown um like Factor like how life + + align:start position:0% +unknown um like Factor like how life + + + align:start position:0% +unknown um like Factor like how life +works is so complex we don't understand + + align:start position:0% +works is so complex we don't understand + + + align:start position:0% +works is so complex we don't understand +it it must be God and maybe there's + + align:start position:0% +it it must be God and maybe there's + + + align:start position:0% +it it must be God and maybe there's +Heaven maybe there's hell the more + + align:start position:0% +Heaven maybe there's hell the more + + + align:start position:0% +Heaven maybe there's hell the more +science advances the less of that there + + align:start position:0% +science advances the less of that there + + + align:start position:0% +science advances the less of that there +is less room there is for that and so I + + align:start position:0% +is less room there is for that and so I + + + align:start position:0% +is less room there is for that and so I +think that's why we don't want like to + + align:start position:0% +think that's why we don't want like to + + + align:start position:0% +think that's why we don't want like to +associate ourselves with like machines + + align:start position:0% +associate ourselves with like machines + + + align:start position:0% +associate ourselves with like machines +cuz like we know every single thing + + align:start position:0% +cuz like we know every single thing + + + align:start position:0% +cuz like we know every single thing +about them and if eventually maybe + + align:start position:0% +about them and if eventually maybe + + + align:start position:0% +about them and if eventually maybe +that's what science is going to do to + + align:start position:0% +that's what science is going to do to + + + align:start position:0% +that's what science is going to do to +humans like we'll know every single + + align:start position:0% +humans like we'll know every single + + + align:start position:0% +humans like we'll know every single +thing about how humans work and all the + + align:start position:0% +thing about how humans work and all the + + + align:start position:0% +thing about how humans work and all the +possibilities there are and then that + + align:start position:0% +possibilities there are and then that + + + align:start position:0% +possibilities there are and then that +would leave no space for like + + align:start position:0% +would leave no space for like + + + align:start position:0% +would leave no space for like +spiritualism I mean keep keep in mind + + align:start position:0% +spiritualism I mean keep keep in mind + + + align:start position:0% +spiritualism I mean keep keep in mind +he's at this he's at the core of + + align:start position:0% +he's at this he's at the core of + + + align:start position:0% +he's at this he's at the core of +cybernetics so he's you know he's one of + + align:start position:0% +cybernetics so he's you know he's one of + + + align:start position:0% +cybernetics so he's you know he's one of +the key people in the field not the only + + align:start position:0% +the key people in the field not the only + + + align:start position:0% +the key people in the field not the only +one but uh he's a really important + + align:start position:0% +one but uh he's a really important + + + align:start position:0% +one but uh he's a really important +thinker um they do have a pretty big + + align:start position:0% +thinker um they do have a pretty big + + + align:start position:0% +thinker um they do have a pretty big +exhibit I think at the MIT Museum when I + + align:start position:0% +exhibit I think at the MIT Museum when I + + + align:start position:0% +exhibit I think at the MIT Museum when I +went last year when I came here on + + align:start position:0% +went last year when I came here on + + + align:start position:0% +went last year when I came here on +cybernetics and how they're like trying + + align:start position:0% +cybernetics and how they're like trying + + + align:start position:0% +cybernetics and how they're like trying +to build this robot they can actually + + align:start position:0% +to build this robot they can actually + + + align:start position:0% +to build this robot they can actually +see and like people are trying to make + + align:start position:0% +see and like people are trying to make + + + align:start position:0% +see and like people are trying to make +human machines a little weird but yeah + + align:start position:0% +human machines a little weird but yeah + + + align:start position:0% +human machines a little weird but yeah +so what is the why why why do you think + + align:start position:0% +so what is the why why why do you think + + + align:start position:0% +so what is the why why why do you think +that is why is it why why are we trying + + align:start position:0% +that is why is it why why are we trying + + + align:start position:0% +that is why is it why why are we trying +to what's driving you know all this new + + align:start position:0% +to what's driving you know all this new + + + align:start position:0% +to what's driving you know all this new +knowledge and machine learning and all + + align:start position:0% +knowledge and machine learning and all + + + align:start position:0% +knowledge and machine learning and all +the and and the effort to create uh sort + + align:start position:0% +the and and the effort to create uh sort + + + align:start position:0% +the and and the effort to create uh sort +of uh + + align:start position:0% +of uh + + + align:start position:0% +of uh +uh higher and higher + + align:start position:0% +uh higher and higher + + + align:start position:0% +uh higher and higher +functioning uh computational devices and + + align:start position:0% +functioning uh computational devices and + + + align:start position:0% +functioning uh computational devices and +to merge them with physical devices what + + align:start position:0% +to merge them with physical devices what + + + align:start position:0% +to merge them with physical devices what +is it want to say laziness it's not that + + align:start position:0% +is it want to say laziness it's not that + + + align:start position:0% +is it want to say laziness it's not that +because we can get them to do it for + + align:start position:0% +because we can get them to do it for + + + align:start position:0% +because we can get them to do it for +us I think it's a search for + + align:start position:0% +us I think it's a search for + + + align:start position:0% +us I think it's a search for +understanding the why we're trying to + + align:start position:0% +understanding the why we're trying to + + + align:start position:0% +understanding the why we're trying to +make uh something that can think the way + + align:start position:0% +make uh something that can think the way + + + align:start position:0% +make uh something that can think the way +a human does because especially in high + + align:start position:0% +a human does because especially in high + + + align:start position:0% +a human does because especially in high +highend uh mathematics and uh physics + + align:start position:0% +highend uh mathematics and uh physics + + + align:start position:0% +highend uh mathematics and uh physics +they use complex models to Model A even + + align:start position:0% +they use complex models to Model A even + + + align:start position:0% +they use complex models to Model A even +more complex system if we we obviously + + align:start position:0% +more complex system if we we obviously + + + align:start position:0% +more complex system if we we obviously +clearly don't understand the brain very + + align:start position:0% +clearly don't understand the brain very + + + align:start position:0% +clearly don't understand the brain very +well at all in terms of cognition and + + align:start position:0% +well at all in terms of cognition and + + + align:start position:0% +well at all in terms of cognition and +thought and way other things but if we + + align:start position:0% +thought and way other things but if we + + + align:start position:0% +thought and way other things but if we +can create a program say + + align:start position:0% +can create a program say + + + align:start position:0% +can create a program say +that moderately closely mimics what's + + align:start position:0% +that moderately closely mimics what's + + + align:start position:0% +that moderately closely mimics what's +what a human can do we can say all right + + align:start position:0% +what a human can do we can say all right + + + align:start position:0% +what a human can do we can say all right +well we don't know exactly how it works + + align:start position:0% +well we don't know exactly how it works + + + align:start position:0% +well we don't know exactly how it works +but this is a really good baseline or a + + align:start position:0% +but this is a really good baseline or a + + + align:start position:0% +but this is a really good baseline or a +rough estimate if how it works so that's + + align:start position:0% +rough estimate if how it works so that's + + + align:start position:0% +rough estimate if how it works so that's +how we're trying to understand cognition + + align:start position:0% +how we're trying to understand cognition + + + align:start position:0% +how we're trying to understand cognition +humans + + align:start position:0% +humans + + + align:start position:0% +humans +are + + align:start position:0% +are + + + align:start position:0% +are +natural quers for knowledge more and + + align:start position:0% +natural quers for knowledge more and + + + align:start position:0% +natural quers for knowledge more and +more deeper understanding of the world + + align:start position:0% +more deeper understanding of the world + + + align:start position:0% +more deeper understanding of the world +and La yeah I think it's some of it's + + align:start position:0% +and La yeah I think it's some of it's + + + align:start position:0% +and La yeah I think it's some of it's +like just basic curiosity of humans and + + align:start position:0% +like just basic curiosity of humans and + + + align:start position:0% +like just basic curiosity of humans and +also it's like why do humans clim as as + + align:start position:0% +also it's like why do humans clim as as + + + align:start position:0% +also it's like why do humans clim as as +they can right so I think it's just + + align:start position:0% +they can right so I think it's just + + + align:start position:0% +they can right so I think it's just +humans can get farther and farther and + + align:start position:0% +humans can get farther and farther and + + + align:start position:0% +humans can get farther and farther and +see how much they can + + align:start position:0% +see how much they can + + + align:start position:0% +see how much they can +do yeah I mean if if if you're in a + + align:start position:0% +do yeah I mean if if if you're in a + + + align:start position:0% +do yeah I mean if if if you're in a +specific area of inquiry um deeper and + + align:start position:0% +specific area of inquiry um deeper and + + + align:start position:0% +specific area of inquiry um deeper and +deeper under understanding of it is is + + align:start position:0% +deeper under understanding of it is is + + + align:start position:0% +deeper under understanding of it is is +it's it's a natural human + + align:start position:0% + + + + align:start position:0% + +impulse uh well according to weer there + + align:start position:0% +impulse uh well according to weer there + + + align:start position:0% +impulse uh well according to weer there +are + + align:start position:0% +are + + + align:start position:0% +are +other there are other drives + + align:start position:0% +other there are other drives + + + align:start position:0% +other there are other drives +um um I mean wier's tremendously + + align:start position:0% +um um I mean wier's tremendously + + + align:start position:0% +um um I mean wier's tremendously +upset by nuclear + + align:start position:0% +upset by nuclear + + + align:start position:0% +upset by nuclear +uh uh the technology that led to nuclear + + align:start position:0% +uh uh the technology that led to nuclear + + + align:start position:0% +uh uh the technology that led to nuclear +weapons this this deeply profoundly + + align:start position:0% +weapons this this deeply profoundly + + + align:start position:0% +weapons this this deeply profoundly +upset + + align:start position:0% +upset + + + align:start position:0% +upset +him because he was worried that um in in + + align:start position:0% +him because he was worried that um in in + + + align:start position:0% +him because he was worried that um in in +creating these entities the control of + + align:start position:0% +creating these entities the control of + + + align:start position:0% +creating these entities the control of +them they had simply rais the level and + + align:start position:0% +them they had simply rais the level and + + + align:start position:0% +them they had simply rais the level and +challenge of + + align:start position:0% +challenge of + + + align:start position:0% +challenge of +controlling them and put this challenge + + align:start position:0% +controlling them and put this challenge + + + align:start position:0% +controlling them and put this challenge +in front of humans and he was he was + + align:start position:0% +in front of humans and he was he was + + + align:start position:0% +in front of humans and he was he was +very very concerned about the human + + align:start position:0% +very very concerned about the human + + + align:start position:0% +very very concerned about the human +ability to stand up to to that um demand + + align:start position:0% +ability to stand up to to that um demand + + + align:start position:0% +ability to stand up to to that um demand +of uh of + + align:start position:0% +of uh of + + + align:start position:0% +of uh of +control so uh weiner did not work on + + align:start position:0% +control so uh weiner did not work on + + + align:start position:0% +control so uh weiner did not work on +this + + align:start position:0% +this + + + align:start position:0% +this +technology uh uh my understanding is + + align:start position:0% +technology uh uh my understanding is + + + align:start position:0% +technology uh uh my understanding is +that he was invited to and cult and and + + align:start position:0% +that he was invited to and cult and and + + + align:start position:0% +that he was invited to and cult and and +cultivated and refused + + align:start position:0% +cultivated and refused + + + align:start position:0% +cultivated and refused +to uh and partly because of his + + align:start position:0% +to uh and partly because of his + + + align:start position:0% +to uh and partly because of his +understanding of uh the problems of + + align:start position:0% +understanding of uh the problems of + + + align:start position:0% +understanding of uh the problems of +control and how do you control these + + align:start position:0% +control and how do you control these + + + align:start position:0% +control and how do you control these +things when you create them so at the at + + align:start position:0% +things when you create them so at the at + + + align:start position:0% +things when you create them so at the at +the core of this of this book is this + + align:start position:0% +the core of this of this book is this + + + align:start position:0% +the core of this of this book is this +terrible problem of the control of uh + + align:start position:0% +terrible problem of the control of uh + + + align:start position:0% +terrible problem of the control of uh +technologies that uh were probably + + align:start position:0% +technologies that uh were probably + + + align:start position:0% +technologies that uh were probably +exhilarating to develop at you know at a + + align:start position:0% +exhilarating to develop at you know at a + + + align:start position:0% +exhilarating to develop at you know at a +theoretical + + align:start position:0% +theoretical + + + align:start position:0% +theoretical +level I mean to solve the problems and + + align:start position:0% +level I mean to solve the problems and + + + align:start position:0% +level I mean to solve the problems and +to create the entity was a huge rush for + + align:start position:0% +to create the entity was a huge rush for + + + align:start position:0% +to create the entity was a huge rush for +a lot of people who were incredibly + + align:start position:0% +a lot of people who were incredibly + + + align:start position:0% +a lot of people who were incredibly +bright + + align:start position:0% +bright + + + align:start position:0% +bright +talented and at the top of their fields + + align:start position:0% +talented and at the top of their fields + + + align:start position:0% +talented and at the top of their fields +and yet to create it once it's created + + align:start position:0% +and yet to create it once it's created + + + align:start position:0% +and yet to create it once it's created +you have to control + + align:start position:0% +you have to control + + + align:start position:0% +you have to control +it so that's why these little Tales of + + align:start position:0% +it so that's why these little Tales of + + + align:start position:0% +it so that's why these little Tales of +you know this uh you know the The + + align:start position:0% +you know this uh you know the The + + + align:start position:0% +you know this uh you know the The +Sorcerer's Apprentice and the monkeyy + + align:start position:0% +Sorcerer's Apprentice and the monkeyy + + + align:start position:0% +Sorcerer's Apprentice and the monkeyy +Paw keep coming back up in this + + align:start position:0% +Paw keep coming back up in this + + + align:start position:0% +Paw keep coming back up in this +piece and this is not he's he's not + + align:start position:0% +piece and this is not he's he's not + + + align:start position:0% +piece and this is not he's he's not +raising this + + align:start position:0% +raising this + + + align:start position:0% +raising this +from you know he's not against but he's + + align:start position:0% +from you know he's not against but he's + + + align:start position:0% +from you know he's not against but he's +not raising this from a humanistic point + + align:start position:0% +not raising this from a humanistic point + + + align:start position:0% +not raising this from a humanistic point +view so much as from a technical point + + align:start position:0% +view so much as from a technical point + + + align:start position:0% +view so much as from a technical point +of view of the control of the things + + align:start position:0% +of view of the control of the things + + + align:start position:0% +of view of the control of the things +that you create I mean who thought that + + align:start position:0% +that you create I mean who thought that + + + align:start position:0% +that you create I mean who thought that +uh at at that time that you know we + + align:start position:0% +uh at at that time that you know we + + + align:start position:0% +uh at at that time that you know we +would be dealing with uh a world of uh + + align:start position:0% +would be dealing with uh a world of uh + + + align:start position:0% +would be dealing with uh a world of uh +you know + + align:start position:0% +you know + + + align:start position:0% +you know +proliferating uh Atomic uh + + align:start position:0% +proliferating uh Atomic uh + + + align:start position:0% +proliferating uh Atomic uh +Weaponry uh you know almost 70 years + + align:start position:0% +Weaponry uh you know almost 70 years + + + align:start position:0% +Weaponry uh you know almost 70 years +later with you know this technology you + + align:start position:0% +later with you know this technology you + + + align:start position:0% +later with you know this technology you +know a lot of different + + align:start position:0% +know a lot of different + + + align:start position:0% +know a lot of different +people uh made use of + + align:start position:0% +people uh made use of + + + align:start position:0% +people uh made use of +it and so the nuclear club club grew and + + align:start position:0% +it and so the nuclear club club grew and + + + align:start position:0% +it and so the nuclear club club grew and +uh he was aware of this set of + + align:start position:0% +uh he was aware of this set of + + + align:start position:0% +uh he was aware of this set of +problems and but this is not what people + + align:start position:0% +problems and but this is not what people + + + align:start position:0% +problems and but this is not what people +were thinking about when they were + + align:start position:0% +were thinking about when they were + + + align:start position:0% +were thinking about when they were +creating the original technology so + + align:start position:0% +creating the original technology so + + + align:start position:0% +creating the original technology so +that's that's that's a deep problem it's + + align:start position:0% +that's that's that's a deep problem it's + + + align:start position:0% +that's that's that's a deep problem it's +just you know what are the impacts what + + align:start position:0% +just you know what are the impacts what + + + align:start position:0% +just you know what are the impacts what +are going to be the costs I mean other + + align:start position:0% +are going to be the costs I mean other + + + align:start position:0% +are going to be the costs I mean other +examples he brings up in the in the book + + align:start position:0% +examples he brings up in the in the book + + + align:start position:0% +examples he brings up in the in the book +uh I didn't we didn't read the whole + + align:start position:0% +uh I didn't we didn't read the whole + + + align:start position:0% +uh I didn't we didn't read the whole +book but later in the book he he brings + + align:start position:0% +book but later in the book he he brings + + + align:start position:0% +book but later in the book he he brings +up even things like + + align:start position:0% +up even things like + + + align:start position:0% +up even things like +healthcare I mean we can create + + align:start position:0% +healthcare I mean we can create + + + align:start position:0% +healthcare I mean we can create +tremendous medical + + align:start position:0% +tremendous medical + + + align:start position:0% +tremendous medical +Technologies but how do we deal with the + + align:start position:0% +Technologies but how do we deal with the + + + align:start position:0% +Technologies but how do we deal with the +you know the the population explosions + + align:start position:0% +you know the the population explosions + + + align:start position:0% +you know the the population explosions +or the extension of populations he's not + + align:start position:0% +or the extension of populations he's not + + + align:start position:0% +or the extension of populations he's not +saying we shouldn't do them but what he + + align:start position:0% +saying we shouldn't do them but what he + + + align:start position:0% +saying we shouldn't do them but what he +is he's he's saying you know as you + + align:start position:0% +is he's he's saying you know as you + + + align:start position:0% +is he's he's saying you know as you +apply all these different Technologies + + align:start position:0% +apply all these different Technologies + + + align:start position:0% +apply all these different Technologies +you're going to have other other + + align:start position:0% +you're going to have other other + + + align:start position:0% +you're going to have other other +problems that you're going to have to to + + align:start position:0% +problems that you're going to have to to + + + align:start position:0% +problems that you're going to have to to +solve and you know it's it's it's it's + + align:start position:0% +solve and you know it's it's it's it's + + + align:start position:0% +solve and you know it's it's it's it's +it's a complex set of + + align:start position:0% +it's a complex set of + + + align:start position:0% +it's a complex set of +questions I mean no no one would uh + + align:start position:0% +questions I mean no no one would uh + + + align:start position:0% +questions I mean no no one would uh +certainly not weer would say well you + + align:start position:0% +certainly not weer would say well you + + + align:start position:0% +certainly not weer would say well you +shouldn't you know uh improve uh you + + align:start position:0% +shouldn't you know uh improve uh you + + + align:start position:0% +shouldn't you know uh improve uh you +know + + align:start position:0% +know + + + align:start position:0% +know +uh delivery uh birth deliveries among + + align:start position:0% +uh delivery uh birth deliveries among + + + align:start position:0% +uh delivery uh birth deliveries among +all the pop I mean he would be you know + + align:start position:0% +all the pop I mean he would be you know + + + align:start position:0% +all the pop I mean he would be you know +he's a he's a definitely a a Humane + + align:start position:0% +he's a he's a definitely a a Humane + + + align:start position:0% +he's a he's a definitely a a Humane +individual who would be + + align:start position:0% +individual who would be + + + align:start position:0% +individual who would be +for all technologies that could improve + + align:start position:0% +for all technologies that could improve + + + align:start position:0% +for all technologies that could improve +human conditions + + align:start position:0% +human conditions + + + align:start position:0% +human conditions +but what he's saying is there going to + + align:start position:0% +but what he's saying is there going to + + + align:start position:0% +but what he's saying is there going to +be a lot of other challenges that are + + align:start position:0% +be a lot of other challenges that are + + + align:start position:0% +be a lot of other challenges that are +going to come along with + + align:start position:0% +going to come along with + + + align:start position:0% +going to come along with +these and so you know so then he uh okay + + align:start position:0% +these and so you know so then he uh okay + + + align:start position:0% +these and so you know so then he uh okay +so he says there are certain there are + + align:start position:0% +so he says there are certain there are + + + align:start position:0% +so he says there are certain there are +certain types of individuals he calls + + align:start position:0% +certain types of individuals he calls + + + align:start position:0% +certain types of individuals he calls +Gadget worshippers who he he does uh uh + + align:start position:0% +Gadget worshippers who he he does uh uh + + + align:start position:0% +Gadget worshippers who he he does uh uh +he does fault and these are people uh he + + align:start position:0% +he does fault and these are people uh he + + + align:start position:0% +he does fault and these are people uh he +says uh a person infatuated with the + + align:start position:0% +says uh a person infatuated with the + + + align:start position:0% +says uh a person infatuated with the +amplica amplification of power and + + align:start position:0% +amplica amplification of power and + + + align:start position:0% +amplica amplification of power and +control through + + align:start position:0% +control through + + + align:start position:0% +control through +technology as well as the transfer of + + align:start position:0% +technology as well as the transfer of + + + align:start position:0% +technology as well as the transfer of +human functions to machines and + + align:start position:0% +human functions to machines and + + + align:start position:0% +human functions to machines and +unquestioning + + align:start position:0% +unquestioning + + + align:start position:0% +unquestioning +servitude so what is this gadget + + align:start position:0% + + + + align:start position:0% + +worshipper + + align:start position:0% +worshipper + + + align:start position:0% +worshipper +why is it why does it emerge in this + + align:start position:0% +why is it why does it emerge in this + + + align:start position:0% +why is it why does it emerge in this +little book what's he talking + + align:start position:0% + + + + align:start position:0% + +about well certainly at at a certain + + align:start position:0% +about well certainly at at a certain + + + align:start position:0% +about well certainly at at a certain +level uh the + + align:start position:0% +level uh the + + + align:start position:0% +level uh the +uses of technology to gain personal + + align:start position:0% +uses of technology to gain personal + + + align:start position:0% +uses of technology to gain personal +ends and to to + + align:start position:0% +ends and to to + + + align:start position:0% +ends and to to +control other people um and it's it's + + align:start position:0% +control other people um and it's it's + + + align:start position:0% +control other people um and it's it's +his it's his argument that there are + + align:start position:0% +his it's his argument that there are + + + align:start position:0% +his it's his argument that there are +certain people who are attracted to + + align:start position:0% +certain people who are attracted to + + + align:start position:0% +certain people who are attracted to +this some people are attracted to you + + align:start position:0% +this some people are attracted to you + + + align:start position:0% +this some people are attracted to you +know power through the manipulation of + + align:start position:0% +know power through the manipulation of + + + align:start position:0% +know power through the manipulation of +of uh + + align:start position:0% +of uh + + + align:start position:0% +of uh +technology and that these are people who + + align:start position:0% +technology and that these are people who + + + align:start position:0% +technology and that these are people who +are uh a + + align:start position:0% +are uh a + + + align:start position:0% +are uh a +problem because uh there is + + align:start position:0% +problem because uh there is + + + align:start position:0% +problem because uh there is +is in inherent in some kind + + align:start position:0% +is in inherent in some kind + + + align:start position:0% +is in inherent in some kind +of uh in in some way in technology this + + align:start position:0% +of uh in in some way in technology this + + + align:start position:0% +of uh in in some way in technology this +this promise of + + align:start position:0% +this promise of + + + align:start position:0% +this promise of +control and that's going to + + align:start position:0% +control and that's going to + + + align:start position:0% +control and that's going to +draw many different types of people what + + align:start position:0% +draw many different types of people what + + + align:start position:0% +draw many different types of people what +one type he talks about as the gadget + + align:start position:0% +one type he talks about as the gadget + + + align:start position:0% +one type he talks about as the gadget +worshipper he says on page 54 it is the + + align:start position:0% +worshipper he says on page 54 it is the + + + align:start position:0% +worshipper he says on page 54 it is the +desire to avoid the personal + + align:start position:0% +desire to avoid the personal + + + align:start position:0% +desire to avoid the personal +responsibility for a dangerous or + + align:start position:0% +responsibility for a dangerous or + + + align:start position:0% +responsibility for a dangerous or +disastrous decision by placing the + + align:start position:0% +disastrous decision by placing the + + + align:start position:0% +disastrous decision by placing the +responsibility elsewhere on chance on + + align:start position:0% +responsibility elsewhere on chance on + + + align:start position:0% +responsibility elsewhere on chance on +human superiors in their policies which + + align:start position:0% +human superiors in their policies which + + + align:start position:0% +human superiors in their policies which +one cannot question or on a mechanical + + align:start position:0% +one cannot question or on a mechanical + + + align:start position:0% +one cannot question or on a mechanical +device which one cannot fully understand + + align:start position:0% +device which one cannot fully understand + + + align:start position:0% +device which one cannot fully understand +but which is has a presumed + + align:start position:0% +but which is has a presumed + + + align:start position:0% +but which is has a presumed +objectivity so this he identifies as the + + align:start position:0% +objectivity so this he identifies as the + + + align:start position:0% +objectivity so this he identifies as the +motive of Gadget + + align:start position:0% +motive of Gadget + + + align:start position:0% +motive of Gadget +worshippers and + + align:start position:0% +worshippers and + + + align:start position:0% +worshippers and +um they would be uh people who are + + align:start position:0% +um they would be uh people who are + + + align:start position:0% +um they would be uh people who are +interested in + + align:start position:0% +interested in + + + align:start position:0% +interested in +making the types of technologies that + + align:start position:0% +making the types of technologies that + + + align:start position:0% +making the types of technologies that +are + + align:start position:0% +are + + + align:start position:0% +are +uh give them power over other + + align:start position:0% +uh give them power over other + + + align:start position:0% +uh give them power over other +people + + align:start position:0% +people + + + align:start position:0% +people +um I'm not I mean I'm not sure exactly + + align:start position:0% +um I'm not I mean I'm not sure exactly + + + align:start position:0% +um I'm not I mean I'm not sure exactly +what he's talking about here I think + + align:start position:0% +what he's talking about here I think + + + align:start position:0% +what he's talking about here I think +he's talking mainly about military + + align:start position:0% +he's talking mainly about military + + + align:start position:0% +he's talking mainly about military +Technologies and things of that sort but + + align:start position:0% +Technologies and things of that sort but + + + align:start position:0% +Technologies and things of that sort but +uh uh you know uh it probably applies to + + align:start position:0% +uh uh you know uh it probably applies to + + + align:start position:0% +uh uh you know uh it probably applies to +many different + + align:start position:0% +many different + + + align:start position:0% +many different +regimes um and that's + + align:start position:0% +regimes um and that's + + + align:start position:0% +regimes um and that's +why this leads them into this whole + + align:start position:0% +why this leads them into this whole + + + align:start position:0% +why this leads them into this whole +discussion of magic what is the + + align:start position:0% +discussion of magic what is the + + + align:start position:0% +discussion of magic what is the +attraction of + + align:start position:0% + + + + align:start position:0% + +magic fig yeah okay we can't figure it + + align:start position:0% +magic fig yeah okay we can't figure it + + + align:start position:0% +magic fig yeah okay we can't figure it +out what does magic + + align:start position:0% + + + + align:start position:0% + +do why do people want magic Mak life + + align:start position:0% +do why do people want magic Mak life + + + align:start position:0% +do why do people want magic Mak life +easier okay magic makes life easier okay + + align:start position:0% +easier okay magic makes life easier okay + + + align:start position:0% +easier okay magic makes life easier okay +but isn't there some deeper motive human + + align:start position:0% +but isn't there some deeper motive human + + + align:start position:0% +but isn't there some deeper motive human +motive why have humans always + + align:start position:0% +motive why have humans always + + + align:start position:0% +motive why have humans always +entertained the worlds of magic and I + + align:start position:0% +entertained the worlds of magic and I + + + align:start position:0% +entertained the worlds of magic and I +mean what is it that attracts humans to + + align:start position:0% +mean what is it that attracts humans to + + + align:start position:0% +mean what is it that attracts humans to +Magic David uh well maybe some people + + align:start position:0% +Magic David uh well maybe some people + + + align:start position:0% +Magic David uh well maybe some people +think it sort of suspense to laws of + + align:start position:0% +think it sort of suspense to laws of + + + align:start position:0% +think it sort of suspense to laws of +nature sort of it sort of gives like + + align:start position:0% +nature sort of it sort of gives like + + + align:start position:0% +nature sort of it sort of gives like +humans that illusion of control okay the + + align:start position:0% +humans that illusion of control okay the + + + align:start position:0% +humans that illusion of control okay the +power magic is is power unquestioning + + align:start position:0% +power magic is is power unquestioning + + + align:start position:0% +power magic is is power unquestioning +power and it's there just you know when + + align:start position:0% +power and it's there just you know when + + + align:start position:0% +power and it's there just you know when +you turn the + + align:start position:0% +you turn the + + + align:start position:0% +you turn the +switch so magic is always uh you know it + + align:start position:0% +switch so magic is always uh you know it + + + align:start position:0% +switch so magic is always uh you know it +it's it's attractive in in some sense uh + + align:start position:0% +it's it's attractive in in some sense uh + + + align:start position:0% +it's it's attractive in in some sense uh +maybe not to everybody but uh certainly + + align:start position:0% +maybe not to everybody but uh certainly + + + align:start position:0% +maybe not to everybody but uh certainly +the idea of using magic to enrich + + align:start position:0% +the idea of using magic to enrich + + + align:start position:0% +the idea of using magic to enrich +yourself or to gain power over other + + align:start position:0% +yourself or to gain power over other + + + align:start position:0% +yourself or to gain power over other +people is an old + + align:start position:0% +people is an old + + + align:start position:0% +people is an old +concept and and and and an old U human + + align:start position:0% +concept and and and and an old U human + + + align:start position:0% +concept and and and and an old U human +endeavor and he's arguing here through + + align:start position:0% +endeavor and he's arguing here through + + + align:start position:0% +endeavor and he's arguing here through +this gadget worshipper + + align:start position:0% +this gadget worshipper + + + align:start position:0% +this gadget worshipper +metaphor that + + align:start position:0% +metaphor that + + + align:start position:0% +metaphor that +in some ways Technologies also offer us + + align:start position:0% +in some ways Technologies also offer us + + + align:start position:0% +in some ways Technologies also offer us +a kind of a magical solution to + + align:start position:0% +a kind of a magical solution to + + + align:start position:0% +a kind of a magical solution to +problems they can and you know gaining + + align:start position:0% +problems they can and you know gaining + + + align:start position:0% +problems they can and you know gaining +that + + align:start position:0% +that + + + align:start position:0% +that +power is is is + + align:start position:0% +power is is is + + + align:start position:0% +power is is is +attractive + + align:start position:0% +attractive + + + align:start position:0% +attractive +um so and and it also tells us something + + align:start position:0% +um so and and it also tells us something + + + align:start position:0% +um so and and it also tells us something +about the nature of some of these uh + + align:start position:0% +about the nature of some of these uh + + + align:start position:0% +about the nature of some of these uh +Technologies so then uh he launches into + + align:start position:0% +Technologies so then uh he launches into + + + align:start position:0% +Technologies so then uh he launches into +the sourcers of Apprentice what's the + + align:start position:0% +the sourcers of Apprentice what's the + + + align:start position:0% +the sourcers of Apprentice what's the +story of the Sorcerers + + align:start position:0% + + + + align:start position:0% + +Apprentice Chris did you get + + align:start position:0% +Apprentice Chris did you get + + + align:start position:0% +Apprentice Chris did you get +that this the monkeys PA oh the monkey P + + align:start position:0% +that this the monkeys PA oh the monkey P + + + align:start position:0% +that this the monkeys PA oh the monkey P +what about uh he he talks about the + + align:start position:0% +what about uh he he talks about the + + + align:start position:0% +what about uh he he talks about the +Sour's Apprentice first did + + align:start position:0% +Sour's Apprentice first did + + + align:start position:0% +Sour's Apprentice first did +anybody you know the story don't you + + align:start position:0% +anybody you know the story don't you + + + align:start position:0% +anybody you know the story don't you +yeah I for exactly what that goes but + + align:start position:0% +yeah I for exactly what that goes but + + + align:start position:0% +yeah I for exactly what that goes but +the The Apprentice goes and you know + + align:start position:0% +the The Apprentice goes and you know + + + align:start position:0% +the The Apprentice goes and you know +experimenting and makes some kind of + + align:start position:0% +experimenting and makes some kind of + + + align:start position:0% +experimenting and makes some kind of +disastrous mistake that goes running a + + align:start position:0% +disastrous mistake that goes running a + + + align:start position:0% +disastrous mistake that goes running a +mu and eventually the the sorcerer has + + align:start position:0% +mu and eventually the the sorcerer has + + + align:start position:0% +mu and eventually the the sorcerer has +to come back and kind of scold and slap + + align:start position:0% +to come back and kind of scold and slap + + + align:start position:0% +to come back and kind of scold and slap +across and wheel everything back in and + + align:start position:0% +across and wheel everything back in and + + + align:start position:0% +across and wheel everything back in and +great if you saw if you saw Disney uh + + align:start position:0% +great if you saw if you saw Disney uh + + + align:start position:0% +great if you saw if you saw Disney uh +Disney had a version of the sorcery the + + align:start position:0% +Disney had a version of the sorcery the + + + align:start position:0% +Disney had a version of the sorcery the +princess I think I gave you a link in + + align:start position:0% +princess I think I gave you a link in + + + align:start position:0% +princess I think I gave you a link in +maybe in the syllabus to this little + + align:start position:0% +maybe in the syllabus to this little + + + align:start position:0% +maybe in the syllabus to this little +cartoon but it was uh the broom and uh + + align:start position:0% +cartoon but it was uh the broom and uh + + + align:start position:0% +cartoon but it was uh the broom and uh +the sorcerer knew how to get the broom + + align:start position:0% +the sorcerer knew how to get the broom + + + align:start position:0% +the sorcerer knew how to get the broom +to go down and fetch water bring it up + + align:start position:0% +to go down and fetch water bring it up + + + align:start position:0% +to go down and fetch water bring it up +and uh he had certain language that he + + align:start position:0% +and uh he had certain language that he + + + align:start position:0% +and uh he had certain language that he +uh he spoke and the broom would spring + + align:start position:0% +uh he spoke and the broom would spring + + + align:start position:0% +uh he spoke and the broom would spring +into action and go fetch the water and + + align:start position:0% +into action and go fetch the water and + + + align:start position:0% +into action and go fetch the water and +the the impre but he also knew how to + + align:start position:0% +the the impre but he also knew how to + + + align:start position:0% +the the impre but he also knew how to +stop the broom so he's away one day and + + align:start position:0% +stop the broom so he's away one day and + + + align:start position:0% +stop the broom so he's away one day and +The + + align:start position:0% +The + + + align:start position:0% +The +Apprentice oh The Apprentice yeah you + + align:start position:0% +Apprentice oh The Apprentice yeah you + + + align:start position:0% +Apprentice oh The Apprentice yeah you +you may have seen the Mickey Mouse + + align:start position:0% +you may have seen the Mickey Mouse + + + align:start position:0% +you may have seen the Mickey Mouse +version Mickey M you know uh the The + + align:start position:0% +version Mickey M you know uh the The + + + align:start position:0% +version Mickey M you know uh the The +Apprentice uh knows how to start the + + align:start position:0% +Apprentice uh knows how to start the + + + align:start position:0% +Apprentice uh knows how to start the +broom and so the broom goes down and + + align:start position:0% +broom and so the broom goes down and + + + align:start position:0% +broom and so the broom goes down and +starts bringing up uh the water but he + + align:start position:0% +starts bringing up uh the water but he + + + align:start position:0% +starts bringing up uh the water but he +doesn't know how to stop it so it you + + align:start position:0% +doesn't know how to stop it so it you + + + align:start position:0% +doesn't know how to stop it so it you +know keeps it keeps going and everything + + align:start position:0% +know keeps it keeps going and everything + + + align:start position:0% +know keeps it keeps going and everything +is getting you know everything is + + align:start position:0% +is getting you know everything is + + + align:start position:0% +is getting you know everything is +getting flooded and uh it's it's out of + + align:start position:0% +getting flooded and uh it's it's out of + + + align:start position:0% +getting flooded and uh it's it's out of +control so it goes back to that that old + + align:start position:0% +control so it goes back to that that old + + + align:start position:0% +control so it goes back to that that old +story of the gollum you know the thing + + align:start position:0% +story of the gollum you know the thing + + + align:start position:0% +story of the gollum you know the thing +that's out of + + align:start position:0% +that's out of + + + align:start position:0% +that's out of +control and you know we know how to + + align:start position:0% +control and you know we know how to + + + align:start position:0% +control and you know we know how to +start it we don't quite know how to shut + + align:start position:0% +start it we don't quite know how to shut + + + align:start position:0% +start it we don't quite know how to shut +it + + align:start position:0% +it + + + align:start position:0% +it +down and you know are there any are + + align:start position:0% +down and you know are there any are + + + align:start position:0% +down and you know are there any are +there any examples of that in modern + + align:start position:0% +there any examples of that in modern + + + align:start position:0% +there any examples of that in modern +technology I mean I don't have anything + + align:start position:0% +technology I mean I don't have anything + + + align:start position:0% +technology I mean I don't have anything +specific in mind + + align:start position:0% + + + + align:start position:0% + +but well maybe our automobiles + + align:start position:0% +but well maybe our automobiles + + + align:start position:0% +but well maybe our automobiles +are I mean you think how could we shut + + align:start position:0% +are I mean you think how could we shut + + + align:start position:0% +are I mean you think how could we shut +down you know the systems that we built + + align:start position:0% +down you know the systems that we built + + + align:start position:0% +down you know the systems that we built +there are many systems we could not shut + + align:start position:0% +there are many systems we could not shut + + + align:start position:0% +there are many systems we could not shut +down and they may be you know they may + + align:start position:0% +down and they may be you know they may + + + align:start position:0% +down and they may be you know they may +not necessarily be taking us in the + + align:start position:0% +not necessarily be taking us in the + + + align:start position:0% +not necessarily be taking us in the +right direction I mean that's not the + + align:start position:0% +right direction I mean that's not the + + + align:start position:0% +right direction I mean that's not the +say that uh we should uh abandon them + + align:start position:0% +say that uh we should uh abandon them + + + align:start position:0% +say that uh we should uh abandon them +immediately or that they were the wrong + + align:start position:0% +immediately or that they were the wrong + + + align:start position:0% +immediately or that they were the wrong +things to create but you know are there + + align:start position:0% +things to create but you know are there + + + align:start position:0% +things to create but you know are there +not areas that we've developed + + align:start position:0% +not areas that we've developed + + + align:start position:0% +not areas that we've developed +technologically that we now are + + align:start position:0% +technologically that we now are + + + align:start position:0% +technologically that we now are +beginning to wonder you know how long + + align:start position:0% +beginning to wonder you know how long + + + align:start position:0% +beginning to wonder you know how long +can + + align:start position:0% +can + + + align:start position:0% +can +this and and how do we stop it well it's + + align:start position:0% +this and and how do we stop it well it's + + + align:start position:0% +this and and how do we stop it well it's +not quite as easy as just shut it down + + align:start position:0% +not quite as easy as just shut it down + + + align:start position:0% +not quite as easy as just shut it down +but uh you know there are plenty of + + align:start position:0% +but uh you know there are plenty of + + + align:start position:0% +but uh you know there are plenty of +technological areas yeah uh that saying + + align:start position:0% +technological areas yeah uh that saying + + + align:start position:0% +technological areas yeah uh that saying +uh how do we stop it made me think of uh + + align:start position:0% +uh how do we stop it made me think of uh + + + align:start position:0% +uh how do we stop it made me think of uh +the cars uh the Toyota cars that + + align:start position:0% +the cars uh the Toyota cars that + + + align:start position:0% +the cars uh the Toyota cars that +wouldn't stop right right the + + align:start position:0% +wouldn't stop right right the + + + align:start position:0% +wouldn't stop right right the +on what people try to stop them and uh + + align:start position:0% +on what people try to stop them and uh + + + align:start position:0% +on what people try to stop them and uh +that's obviously not really a great + + align:start position:0% +that's obviously not really a great + + + align:start position:0% +that's obviously not really a great +example but it is example of uh + + align:start position:0% +example but it is example of uh + + + align:start position:0% +example but it is example of uh +technology and all right it's doing what + + align:start position:0% +technology and all right it's doing what + + + align:start position:0% +technology and all right it's doing what +we told to but now we + + align:start position:0% +we told to but now we + + + align:start position:0% +we told to but now we +don't yes we could manually open the + + align:start position:0% +don't yes we could manually open the + + + align:start position:0% +don't yes we could manually open the +engine and like start disconnecting + + align:start position:0% +engine and like start disconnecting + + + align:start position:0% +engine and like start disconnecting +things till it turns off but it's not + + align:start position:0% +things till it turns off but it's not + + + align:start position:0% +things till it turns off but it's not +really + + align:start position:0% +really + + + align:start position:0% +really +reasonable option okay the same way if + + align:start position:0% +reasonable option okay the same way if + + + align:start position:0% +reasonable option okay the same way if +like computer starts malfunction we can + + align:start position:0% +like computer starts malfunction we can + + + align:start position:0% +like computer starts malfunction we can +unplug it yeah but I mean what does that + + align:start position:0% +unplug it yeah but I mean what does that + + + align:start position:0% +unplug it yeah but I mean what does that +do for us yeah yeah so uh I mean again + + align:start position:0% +do for us yeah yeah so uh I mean again + + + align:start position:0% +do for us yeah yeah so uh I mean again +this is a this is I mean he's trying to + + align:start position:0% +this is a this is I mean he's trying to + + + align:start position:0% +this is a this is I mean he's trying to +get people he's not saying these you + + align:start position:0% +get people he's not saying these you + + + align:start position:0% +get people he's not saying these you +know Technologies are he's just trying + + align:start position:0% +know Technologies are he's just trying + + + align:start position:0% +know Technologies are he's just trying +to get people to think more deeply about + + align:start position:0% +to get people to think more deeply about + + + align:start position:0% +to get people to think more deeply about +what they're involved in and not simply + + align:start position:0% +what they're involved in and not simply + + + align:start position:0% +what they're involved in and not simply +look at the surface but to probe the + + align:start position:0% +look at the surface but to probe the + + + align:start position:0% +look at the surface but to probe the +deeper impact and + + align:start position:0% +deeper impact and + + + align:start position:0% +deeper impact and +meaning and and to also design when they + + align:start position:0% +meaning and and to also design when they + + + align:start position:0% +meaning and and to also design when they +do design to design more + + align:start position:0% +do design to design more + + + align:start position:0% +do design to design more +thoroughly so that you + + align:start position:0% +thoroughly so that you + + + align:start position:0% +thoroughly so that you +know possible problems are + + align:start position:0% +know possible problems are + + + align:start position:0% +know possible problems are +anticipated even so it's unlikely that + + align:start position:0% +anticipated even so it's unlikely that + + + align:start position:0% +anticipated even so it's unlikely that +all the problems will + + align:start position:0% +all the problems will + + + align:start position:0% +all the problems will +be okay so the monkeys paw again uh the + + align:start position:0% +be okay so the monkeys paw again uh the + + + align:start position:0% +be okay so the monkeys paw again uh the +whole tale of uh now the + + align:start position:0% +whole tale of uh now the + + + align:start position:0% +whole tale of uh now the +uh + + align:start position:0% +uh + + + align:start position:0% +uh +uh so what is the uh what is the + + align:start position:0% +uh so what is the uh what is the + + + align:start position:0% +uh so what is the uh what is the +monkey's + + align:start position:0% +monkey's + + + align:start position:0% +monkey's +paw he says here on page + + align:start position:0% +paw he says here on page + + + align:start position:0% +paw he says here on page + + align:start position:0% + + + align:start position:0% +um in this tale an English working + + align:start position:0% +um in this tale an English working + + + align:start position:0% +um in this tale an English working +family is sitting down to dinner in its + + align:start position:0% +family is sitting down to dinner in its + + + align:start position:0% +family is sitting down to dinner in its +kitchen the sun leaves to work at a fa + + align:start position:0% +kitchen the sun leaves to work at a fa + + + align:start position:0% +kitchen the sun leaves to work at a fa +Factory and the old parents listen to + + align:start position:0% +Factory and the old parents listen to + + + align:start position:0% +Factory and the old parents listen to +the tales of their + + align:start position:0% +the tales of their + + + align:start position:0% +the tales of their +guest a sergeant major backed from + + align:start position:0% +guest a sergeant major backed from + + + align:start position:0% +guest a sergeant major backed from +service in the Indian army he tells them + + align:start position:0% +service in the Indian army he tells them + + + align:start position:0% +service in the Indian army he tells them +of Indian magic and shows them a dried + + align:start position:0% +of Indian magic and shows them a dried + + + align:start position:0% +of Indian magic and shows them a dried +monkeyy paw which he tells them is a + + align:start position:0% +monkeyy paw which he tells them is a + + + align:start position:0% +monkeyy paw which he tells them is a +Talisman which has been been endowed by + + align:start position:0% +Talisman which has been been endowed by + + + align:start position:0% +Talisman which has been been endowed by +an Indian holy man with the virtue of + + align:start position:0% +an Indian holy man with the virtue of + + + align:start position:0% +an Indian holy man with the virtue of +giving three wishes to each of three + + align:start position:0% +giving three wishes to each of three + + + align:start position:0% +giving three wishes to each of three +successive + + align:start position:0% +successive + + + align:start position:0% +successive +owners this he says was to prove the + + align:start position:0% +owners this he says was to prove the + + + align:start position:0% +owners this he says was to prove the +Folly of defying + + align:start position:0% +Folly of defying + + + align:start position:0% +Folly of defying +fate important to remember this that + + align:start position:0% +fate important to remember this that + + + align:start position:0% +fate important to remember this that +phrase there the Folly of defying + + align:start position:0% +phrase there the Folly of defying + + + align:start position:0% +phrase there the Folly of defying +fate he says that he does not know what + + align:start position:0% +fate he says that he does not know what + + + align:start position:0% +fate he says that he does not know what +were the first two wishes wishes of the + + align:start position:0% +were the first two wishes wishes of the + + + align:start position:0% +were the first two wishes wishes of the +first owner but that the last one was + + align:start position:0% +first owner but that the last one was + + + align:start position:0% +first owner but that the last one was +for + + align:start position:0% +for + + + align:start position:0% +for +death This should have told him + + align:start position:0% +death This should have told him + + + align:start position:0% +death This should have told him +something he self was the second owner + + align:start position:0% +something he self was the second owner + + + align:start position:0% +something he self was the second owner +but his experiences were too terrible to + + align:start position:0% +but his experiences were too terrible to + + + align:start position:0% +but his experiences were too terrible to +relate he's about to cast the p a Coal + + align:start position:0% +relate he's about to cast the p a Coal + + + align:start position:0% +relate he's about to cast the p a Coal +Fire when his host retrieves it and + + align:start position:0% +Fire when his host retrieves it and + + + align:start position:0% +Fire when his host retrieves it and +despite all the sergeant major can do + + align:start position:0% +despite all the sergeant major can do + + + align:start position:0% +despite all the sergeant major can do +wishes for 200 + + align:start position:0% +wishes for 200 + + + align:start position:0% +wishes for 200 +lb shortly thereafter there is a knock + + align:start position:0% +lb shortly thereafter there is a knock + + + align:start position:0% +lb shortly thereafter there is a knock +at the door a very solemn gentleman is + + align:start position:0% +at the door a very solemn gentleman is + + + align:start position:0% +at the door a very solemn gentleman is +there from the company which has + + align:start position:0% +there from the company which has + + + align:start position:0% +there from the company which has +employed his son as gently as he can he + + align:start position:0% +employed his son as gently as he can he + + + align:start position:0% +employed his son as gently as he can he +breaks the news that the son has been + + align:start position:0% +breaks the news that the son has been + + + align:start position:0% +breaks the news that the son has been +killed in an accident at the + + align:start position:0% +killed in an accident at the + + + align:start position:0% +killed in an accident at the +factory without recognizing any + + align:start position:0% +factory without recognizing any + + + align:start position:0% +factory without recognizing any +responsibility in the matter the company + + align:start position:0% +responsibility in the matter the company + + + align:start position:0% +responsibility in the matter the company +offers its sympathy and 200b as a as a + + align:start position:0% +offers its sympathy and 200b as a as a + + + align:start position:0% +offers its sympathy and 200b as a as a +solatium as a compensation the parents + + align:start position:0% +solatium as a compensation the parents + + + align:start position:0% +solatium as a compensation the parents +are distracted and at the mother's + + align:start position:0% +are distracted and at the mother's + + + align:start position:0% +are distracted and at the mother's +suggestion they wish the sun Back Again + + align:start position:0% +suggestion they wish the sun Back Again + + + align:start position:0% +suggestion they wish the sun Back Again +by now it is dark without a dark windy + + align:start position:0% +by now it is dark without a dark windy + + + align:start position:0% +by now it is dark without a dark windy +night again there is a knocking at the + + align:start position:0% +night again there is a knocking at the + + + align:start position:0% +night again there is a knocking at the +door somehow the parents know that it is + + align:start position:0% +door somehow the parents know that it is + + + align:start position:0% +door somehow the parents know that it is +their son but not in the flesh the story + + align:start position:0% +their son but not in the flesh the story + + + align:start position:0% +their son but not in the flesh the story +ends with the third wish that the ghost + + align:start position:0% +ends with the third wish that the ghost + + + align:start position:0% +ends with the third wish that the ghost +should go + + align:start position:0% +should go + + + align:start position:0% +should go +away the theme of all these Tales is the + + align:start position:0% +away the theme of all these Tales is the + + + align:start position:0% +away the theme of all these Tales is the +danger of magic this seems to lie in the + + align:start position:0% +danger of magic this seems to lie in the + + + align:start position:0% +danger of magic this seems to lie in the +fact that the operation of magic is + + align:start position:0% +fact that the operation of magic is + + + align:start position:0% +fact that the operation of magic is +singularly literal minded which Laura + + align:start position:0% +singularly literal minded which Laura + + + align:start position:0% +singularly literal minded which Laura +mentioned and that if it grants you + + align:start position:0% +mentioned and that if it grants you + + + align:start position:0% +mentioned and that if it grants you +anything at all it grants you uh it + + align:start position:0% +anything at all it grants you uh it + + + align:start position:0% +anything at all it grants you uh it +grants what you ask for not what you + + align:start position:0% +grants what you ask for not what you + + + align:start position:0% +grants what you ask for not what you +should have asked for or what you + + align:start position:0% +should have asked for or what you + + + align:start position:0% +should have asked for or what you +intend so this is his uh tale and he you + + align:start position:0% +intend so this is his uh tale and he you + + + align:start position:0% +intend so this is his uh tale and he you +know again he's uh using this to uh to + + align:start position:0% +know again he's uh using this to uh to + + + align:start position:0% +know again he's uh using this to uh to +suggest yes that there are many things + + align:start position:0% +suggest yes that there are many things + + + align:start position:0% +suggest yes that there are many things +that + + align:start position:0% +that + + + align:start position:0% +that +uh we we can + + align:start position:0% +uh we we can + + + align:start position:0% +uh we we can +develop and uh they may not be what we + + align:start position:0% +develop and uh they may not be what we + + + align:start position:0% +develop and uh they may not be what we +thought they would + + align:start position:0% +thought they would + + + align:start position:0% +thought they would +be his argument that + + align:start position:0% +be his argument that + + + align:start position:0% +be his argument that +uh sorcery is um uh is is in some ways + + align:start position:0% +uh sorcery is um uh is is in some ways + + + align:start position:0% +uh sorcery is um uh is is in some ways +science is similar in some ways to + + align:start position:0% +science is similar in some ways to + + + align:start position:0% +science is similar in some ways to +sorcery I mean sorcery is Magic science + + align:start position:0% +sorcery I mean sorcery is Magic science + + + align:start position:0% +sorcery I mean sorcery is Magic science +is not Magic + + align:start position:0% +is not Magic + + + align:start position:0% +is not Magic +but there are certain kinds of power + + align:start position:0% +but there are certain kinds of power + + + align:start position:0% +but there are certain kinds of power +that + + align:start position:0% +that + + + align:start position:0% +that +are uh delivered + + align:start position:0% +are uh delivered + + + align:start position:0% +are uh delivered +through the applications of Science and + + align:start position:0% +through the applications of Science and + + + align:start position:0% +through the applications of Science and +again his his he's not a he's not a lite + + align:start position:0% +again his his he's not a he's not a lite + + + align:start position:0% +again his his he's not a he's not a lite +or a I mean he's at the core of a lot of + + align:start position:0% +or a I mean he's at the core of a lot of + + + align:start position:0% +or a I mean he's at the core of a lot of +but what he what he is saying is uh we + + align:start position:0% +but what he what he is saying is uh we + + + align:start position:0% +but what he what he is saying is uh we +need to think about these the people who + + align:start position:0% +need to think about these the people who + + + align:start position:0% +need to think about these the people who +develop it need to take some kind of uh + + align:start position:0% +develop it need to take some kind of uh + + + align:start position:0% +develop it need to take some kind of uh +role in thinking about what it's + + align:start position:0% +role in thinking about what it's + + + align:start position:0% +role in thinking about what it's +applications will be and what it social + + align:start position:0% +applications will be and what it social + + + align:start position:0% +applications will be and what it social +impact will be uh they can't simply they + + align:start position:0% +impact will be uh they can't simply they + + + align:start position:0% +impact will be uh they can't simply they +shouldn't + + align:start position:0% +shouldn't + + + align:start position:0% +shouldn't +simply be the technical people who say + + align:start position:0% +simply be the technical people who say + + + align:start position:0% +simply be the technical people who say +well it's somebody else's problem I + + align:start position:0% +well it's somebody else's problem I + + + align:start position:0% +well it's somebody else's problem I +develop it but you know it's not my + + align:start position:0% +develop it but you know it's not my + + + align:start position:0% +develop it but you know it's not my +problem to control it uh he he he's + + align:start position:0% +problem to control it uh he he he's + + + align:start position:0% +problem to control it uh he he he's +saying that this + + align:start position:0% +saying that this + + + align:start position:0% +saying that this +responsibility extends to the people who + + align:start position:0% +responsibility extends to the people who + + + align:start position:0% +responsibility extends to the people who +make it who make the make the + + align:start position:0% +make it who make the make the + + + align:start position:0% +make it who make the make the +Technologies so so his uh + + align:start position:0% +Technologies so so his uh + + + align:start position:0% +Technologies so so his uh +I mean his message is is also deals with + + align:start position:0% +I mean his message is is also deals with + + + align:start position:0% +I mean his message is is also deals with +simply the fact that uh + + align:start position:0% +simply the fact that uh + + + align:start position:0% +simply the fact that uh +automization you know we are automize + + align:start position:0% +automization you know we are automize + + + align:start position:0% +automization you know we are automize +everything I mean for many many reasons + + align:start position:0% +everything I mean for many many reasons + + + align:start position:0% +everything I mean for many many reasons +I mean we interact now with all kinds of + + align:start position:0% +I mean we interact now with all kinds of + + + align:start position:0% +I mean we interact now with all kinds of +devices and all kinds of processes have + + align:start position:0% +devices and all kinds of processes have + + + align:start position:0% +devices and all kinds of processes have +been + + align:start position:0% +been + + + align:start position:0% +been +automated a goal-seeking mechanism will + + align:start position:0% +automated a goal-seeking mechanism will + + + align:start position:0% +automated a goal-seeking mechanism will +not necessarily seek our goals unless we + + align:start position:0% +not necessarily seek our goals unless we + + + align:start position:0% +not necessarily seek our goals unless we +design it for that purpose and in that + + align:start position:0% +design it for that purpose and in that + + + align:start position:0% +design it for that purpose and in that +designing we must foresee all the steps + + align:start position:0% +designing we must foresee all the steps + + + align:start position:0% +designing we must foresee all the steps +of the process process for which it is + + align:start position:0% +of the process process for which it is + + + align:start position:0% +of the process process for which it is +designed that's what I was just + + align:start position:0% +designed that's what I was just + + + align:start position:0% +designed that's what I was just +mentioning the penalties for errors of + + align:start position:0% +mentioning the penalties for errors of + + + align:start position:0% +mentioning the penalties for errors of +foresight will be enormously increased + + align:start position:0% +foresight will be enormously increased + + + align:start position:0% +foresight will be enormously increased +as automization comes into its full use + + align:start position:0% +as automization comes into its full use + + + align:start position:0% +as automization comes into its full use +so this is this is again a concern from + + align:start position:0% +so this is this is again a concern from + + + align:start position:0% +so this is this is again a concern from +somebody who's at the core of this + + align:start position:0% + + + + align:start position:0% + +process and this this is also my + + align:start position:0% +process and this this is also my + + + align:start position:0% +process and this this is also my +favorite quote the world of the future + + align:start position:0% +favorite quote the world of the future + + + align:start position:0% +favorite quote the world of the future +will be in ever more demanding struggle + + align:start position:0% +will be in ever more demanding struggle + + + align:start position:0% +will be in ever more demanding struggle +against the limitations of our + + align:start position:0% +against the limitations of our + + + align:start position:0% +against the limitations of our +intelligence not a comfortable hammock + + align:start position:0% +intelligence not a comfortable hammock + + + align:start position:0% +intelligence not a comfortable hammock +in which we can lie down to be waited + + align:start position:0% +in which we can lie down to be waited + + + align:start position:0% +in which we can lie down to be waited +upon by our robot + + align:start position:0% +upon by our robot + + + align:start position:0% +upon by our robot +slaves so he foresaw the weak link here + + align:start position:0% +slaves so he foresaw the weak link here + + + align:start position:0% +slaves so he foresaw the weak link here +as the human + + align:start position:0% +as the human + + + align:start position:0% +as the human +link the ability of humans to kind of + + align:start position:0% +link the ability of humans to kind of + + + align:start position:0% +link the ability of humans to kind of +keep up with what's happening and to + + align:start position:0% +keep up with what's happening and to + + + align:start position:0% +keep up with what's happening and to +understand and control it and to use it + + align:start position:0% +understand and control it and to use it + + + align:start position:0% +understand and control it and to use it +wisely Jake I think that's really kind + + align:start position:0% +wisely Jake I think that's really kind + + + align:start position:0% +wisely Jake I think that's really kind +of his whole point overall is that uh + + align:start position:0% +of his whole point overall is that uh + + + align:start position:0% +of his whole point overall is that uh +the limiting factor is our ability to + + align:start position:0% +the limiting factor is our ability to + + + align:start position:0% +the limiting factor is our ability to +convey to our machines or robots or + + align:start position:0% +convey to our machines or robots or + + + align:start position:0% +convey to our machines or robots or +artificial intelligence or software what + + align:start position:0% +artificial intelligence or software what + + + align:start position:0% +artificial intelligence or software what +exactly you want from it and that's + + align:start position:0% +exactly you want from it and that's + + + align:start position:0% +exactly you want from it and that's +that's the why + + align:start position:0% +that's the why + + + align:start position:0% +that's the why +there's however many different + + align:start position:0% +there's however many different + + + align:start position:0% +there's however many different +programming languages there's different + + align:start position:0% +programming languages there's different + + + align:start position:0% +programming languages there's different +ways to program a different certain + + align:start position:0% +ways to program a different certain + + + align:start position:0% +ways to program a different certain +program there's so much variability + + align:start position:0% +program there's so much variability + + + align:start position:0% +program there's so much variability +because there is no perfect and exact + + align:start position:0% +because there is no perfect and exact + + + align:start position:0% +because there is no perfect and exact +way to make it do exactly what we want + + align:start position:0% +way to make it do exactly what we want + + + align:start position:0% +way to make it do exactly what we want +we have to kind of use work throughs + + align:start position:0% +we have to kind of use work throughs + + + align:start position:0% +we have to kind of use work throughs +work arounds and different things to try + + align:start position:0% +work arounds and different things to try + + + align:start position:0% +work arounds and different things to try +try to get what we want there's no way + + align:start position:0% +try to get what we want there's no way + + + align:start position:0% +try to get what we want there's no way +to you can't just tell a computer do + + align:start position:0% +to you can't just tell a computer do + + + align:start position:0% +to you can't just tell a computer do +this and have it come up with the way to + + align:start position:0% +this and have it come up with the way to + + + align:start position:0% +this and have it come up with the way to +do you to say take this step this step + + align:start position:0% +do you to say take this step this step + + + align:start position:0% +do you to say take this step this step +if this and that the case is this case + + align:start position:0% +if this and that the case is this case + + + align:start position:0% +if this and that the case is this case +this case this case else and all sorts + + align:start position:0% +this case this case else and all sorts + + + align:start position:0% +this case this case else and all sorts +of other things try to get what we want + + align:start position:0% +of other things try to get what we want + + + align:start position:0% +of other things try to get what we want +there's no way to just say do it and + + align:start position:0% +there's no way to just say do it and + + + align:start position:0% +there's no way to just say do it and +have to get done yeah yeah that's where + + align:start position:0% +have to get done yeah yeah that's where + + + align:start position:0% +have to get done yeah yeah that's where +the challenge is TR so that's the + + align:start position:0% +the challenge is TR so that's the + + + align:start position:0% +the challenge is TR so that's the +challenge of design is is to understand + + align:start position:0% +challenge of design is is to understand + + + align:start position:0% +challenge of design is is to understand +the design design and to see how its + + align:start position:0% +the design design and to see how its + + + align:start position:0% +the design design and to see how its +expression is ultimately going to + + align:start position:0% +expression is ultimately going to + + + align:start position:0% +expression is ultimately going to +ultimately take place and the full range + + align:start position:0% +ultimately take place and the full range + + + align:start position:0% +ultimately take place and the full range +of things because there are many many + + align:start position:0% +of things because there are many many + + + align:start position:0% +of things because there are many many +things that have been designed with + + align:start position:0% +things that have been designed with + + + align:start position:0% +things that have been designed with +perfectly wonderful intentions and uh + + align:start position:0% +perfectly wonderful intentions and uh + + + align:start position:0% +perfectly wonderful intentions and uh +that have turned out not to really work + + align:start position:0% +that have turned out not to really work + + + align:start position:0% +that have turned out not to really work +the way that we uh the designers + + align:start position:0% +the way that we uh the designers + + + align:start position:0% +the way that we uh the designers +intended them to even though they had + + align:start position:0% +intended them to even though they had + + + align:start position:0% +intended them to even though they had +the best of + + align:start position:0% +the best of + + + align:start position:0% +the best of +intentions so that's that's a big and + + align:start position:0% +intentions so that's that's a big and + + + align:start position:0% +intentions so that's that's a big and +especially as Things become more and + + align:start position:0% +especially as Things become more and + + + align:start position:0% +especially as Things become more and +more powerful and as Computing really + + align:start position:0% +more powerful and as Computing really + + + align:start position:0% +more powerful and as Computing really +magnifies our + + align:start position:0% +magnifies our + + + align:start position:0% +magnifies our +power um you know we are definitely in a + + align:start position:0% +power um you know we are definitely in a + + + align:start position:0% +power um you know we are definitely in a +in a more complex + + align:start position:0% + + + + align:start position:0% + +World okay you see some of these + + align:start position:0% +World okay you see some of these + + + align:start position:0% +World okay you see some of these +environments we we we live in you know + + align:start position:0% +environments we we we live in you know + + + align:start position:0% +environments we we we live in you know +can you imagine being in the Space + + align:start position:0% +can you imagine being in the Space + + + align:start position:0% +can you imagine being in the Space +Capsule and going off to uh you know the + + align:start position:0% +Capsule and going off to uh you know the + + + align:start position:0% +Capsule and going off to uh you know the +moon it's like trying to you know some + + align:start position:0% +moon it's like trying to you know some + + + align:start position:0% +moon it's like trying to you know some +of you may have seen the the film + + align:start position:0% +of you may have seen the the film + + + align:start position:0% +of you may have seen the the film +U uh you know just just trying to + + align:start position:0% +U uh you know just just trying to + + + align:start position:0% +U uh you know just just trying to +be uh aware of what's happening in that + + align:start position:0% +be uh aware of what's happening in that + + + align:start position:0% +be uh aware of what's happening in that +kind of a system I mean humans have + + align:start position:0% +kind of a system I mean humans have + + + align:start position:0% +kind of a system I mean humans have +really uh put a a tremendous challenge + + align:start position:0% +really uh put a a tremendous challenge + + + align:start position:0% +really uh put a a tremendous challenge +to + + align:start position:0% +to + + + align:start position:0% +to +themselves okay so uh he's uh you know + + align:start position:0% +themselves okay so uh he's uh you know + + + align:start position:0% +themselves okay so uh he's uh you know +this is a great little book uh you know + + align:start position:0% +this is a great little book uh you know + + + align:start position:0% +this is a great little book uh you know +when you get some time I hope you're + + align:start position:0% +when you get some time I hope you're + + + align:start position:0% +when you get some time I hope you're +saving some of these books that uh you + + align:start position:0% +saving some of these books that uh you + + + align:start position:0% +saving some of these books that uh you +have the links and things of that sort + + align:start position:0% +have the links and things of that sort + + + align:start position:0% +have the links and things of that sort +because it's definitely worth revisiting + + align:start position:0% +because it's definitely worth revisiting + + + align:start position:0% +because it's definitely worth revisiting +this book it's a wonderful little book + + align:start position:0% +this book it's a wonderful little book + + + align:start position:0% +this book it's a wonderful little book +uh and U in some ways uh it was his his + + align:start position:0% +uh and U in some ways uh it was his his + + + align:start position:0% +uh and U in some ways uh it was his his +swans song his message to the world of + + align:start position:0% +swans song his message to the world of + + + align:start position:0% +swans song his message to the world of +uh from you know his accumulated + + align:start position:0% +uh from you know his accumulated + + + align:start position:0% +uh from you know his accumulated +wisdom uh and uh you know a life of uh + + align:start position:0% +wisdom uh and uh you know a life of uh + + + align:start position:0% +wisdom uh and uh you know a life of uh +incredible + + align:start position:0% + + + + align:start position:0% + +achievement \ No newline at end of file diff --git a/1_dMnMLbIok.txt b/1_dMnMLbIok.txt new file mode 100644 index 0000000000000000000000000000000000000000..992938650fd155fc8275a607663371c0ea89b99a --- /dev/null +++ b/1_dMnMLbIok.txt @@ -0,0 +1,3179 @@ +The following +content is provided + +under a Creative +Commons license. + +Your support will help MIT +OpenCourseWare continue + +to offer high quality +educational resources for free. + +To make a donation or +view additional materials + +from hundreds of MIT courses, +visit MIT OpenCourseWare + +at ocw.mit.edu. + +PROFESSOR: OK, let's start. + +So we are going to change +perspective again and think + +in terms of lattice models. + +So for the first +part of this course, + +I was trying to change +your perspective + +from thinking in terms of +microscopic degrees of freedom + +to a statistical field. + +Now we are going to go back +and try to build pictures + +around things that +look more microscopic. + +Typically, in many solid +state configurations, + +we are dealing with transitions +that take place on a lattice. + +For example, imagine a square +lattice, which is easy to draw, + +but there could be all kinds +of cubic and more complex + +lattices. + +And then, at each +side of this lattice, + +you may have one microscopic +degrees of freedom + +that is ultimately participating +in the ordering and the phase + +transition that +you have in mind. + +Could, for example, +be a spin, or it + +could be one atom +in a binary mixture. + +And what you would like to do +is to construct a partition + +function, again, by summing +over all degrees of freedom. + +And we need some +kind of Hamiltonian. + +And what we are going +to assume governs + +that Hamiltonian is the analog +of this locality assumption + +that we have in +statistical field theories. + +That is, we are going +to assume that one + +of our degrees of +freedom essentially + +talks to a small +neighborhood around it. + +And the simplest +neighborhood would + +be to basically talk to +the nearest neighbor. + +So if I, for example, +assign index i + +to each side of +the lattice, let's + +say I have some variable at each +side that could be something. + +Let's call it SI. + +Then my partition +function would be + +obtained by summing +over all configurations. + +And the weight I'm going to +assume in terms of this lattice + +picture to be a sum +over interactions + +that exist between +pairs of sides. + +So that's already an assumption +that it's a pairwise thing. + +And I'm going to use this +symbol ij with an angular + +bracket along it, +around it, to indicate + +the sum over nearest neighbors. + +And there is some +function of the variables + +that live on these neighbors. + +So basically, in the +picture that I have drawn, + +interactions exist only between +the places that you see lines. + +So that this pin +does not interact + +with this pin, this +pin, or this pin, + +but it interacts +with these four pins, + +to which it is near neighbor. + +Now clearly, the form +of the interaction + +has to be dictated by +your degrees of freedom. + +And the idea of +this representation, + +as opposed to the previous +statistical field theory + +that we had, is that in +several important instances, + +you may want to know not only +what these universal properties + +are, but also, let's say, the +explicit temperature or phase + +diagram of the system as a +function of external parameters + +as well as temperature. + +And if you have some idea of +how your microscopic degrees + +of freedom interact +with each other, + +you should be able to solve +this kind of partition function, + +get the singularities, +et cetera. + +So let's look at some simple +versions of this construction + +and gradually discuss +the kinds of things + +that we could do with it. + +So some simple models. + +The simplest one +is the Ising model + +where the variable that +you have at each side + +has two possibilities. + +So it's a binary variable in +the context of a binary alloy. + +It could be, let's +say, atom A or atom + +B that is occupying +a particular site. + +There are also cases +where there will be some-- + +if this is a surface and +you're absorbing particles + +on top of it, there could be +a particle sitting here or not + +sitting here. + +So that would be also another +example of a binary variable. + +So you could indicate that by +empty or occupied, zero or one. + +But let's indicate it by +plus or minus one as the two + +possible values +that you can have. + +Now, if I look at the +analog of the interaction + +that I have between two +sites that are neighboring + +each other, what +can I write down? + +Well, the most general +thing that I can write down + +is, first of all, a +constant I can put, + +such as shift of energy. + +There could be a linear +term in-- let's put + +all of these with minus signs. + +Sigma i and sigma j. + +I assume that it is symmetric +with respect to the two sides. + +For reasons to become +apparent shortly, + +I will divide by z, which +is the coordination number. + +How many bonds per side? + +And then the next +term that I can + +put is something like +j sigma i sigma j. + +And actually, I can't +put anything else. + +Because if you s of this as +a power series in sigma i + +and sigma j, and sigma +has only two values, + +it will terminate here. + +Because any higher power of +sigma is either one or sigma + +itself. + +So another way of writing +this is that the partition + +function of the Ising model is +obtained by summing over all 2 + +to the n configurations +that I have. + +If I have a lattice +of n sides, each side + +can have two possibilities of +a kind of Hamiltonian, which + +is basically some constant +plus h sum over i sigma i kind + +of field that prefers one +side or the other side. + +So it is an analog of a magnetic +field in this binary system. + +And basically, I convert it from +a description that is overall + +balanced to a description +overall sides. + +And that's why I had put the +coordination number there. + +It's kind of a +matter of convention. + +And then a term that +prefers neighboring sites + +to be aligned as +long as k positive. + +So that's one +example of a model. + +Another model that +we will also look at + +is what I started to +draw at the beginning. + +That is, at each site, +you have a vector. + +And again, going in terms of +the pictures that we had before, + +let's imagine that we have a +vector that has n components. + +So SI is something +that is in RN. + +And I will assume that the +magnitude of this vector + +is one. + +So essentially, +imagine that you have + +a unit vector, and each +site that can rotate. + +So if n equals to one, you +have essentially one component + +vector. + +Its square has to +be one, so the two + +values that it can have +are plus one and minus one. + +So the n equals to one case +is the Ising model again. + +So this ON is a +generalization of the Ising + +model to multiple components. + +n equals to two corresponds +to a unit vector + +that can take any angle +in two dimensions. + +And that is usually +given the name xy model. + +n equals to three is +something that maybe you + +want to use to describe +magnetic ions in this lattice. + +And classically, the direction +of this ion could be anywhere. + +The spin of the +ion can be anywhere + +on the surface of a sphere. + +So that's three +components, and this model + +is sometimes called +the Heisenberg model. + +Yes. + +AUDIENCE: In the +Ising model, what's + +the correspondence between g +hat h hat j hat and g, h, and k? + +PROFESSOR: Minus beta. + +Yeah. + +So maybe I should have written. + +In order to take this-- if I +think of this as energy pair + +bond, then in order to +get the Boltzmann weight, + +I have to put a minus beta. + +So I would have said +that this g, for example, + +is minus beta g hat. + +k is minus beta j hat. + +And h is minus beta h hat. + +So I should have +emphasized that. + +What I meant by b-- +actually, I wrote + +b-- so what I should have +done here to be consistent, + +let's write this as minus beta. + +Thank you. + +That was important. + +If I described these b's +as being energies, then + +minus beta times +that will be what + +will go in the Boltzmann factor. + +OK + +So whereas these were examples +that we had more or less seen + +their continuum version in +the Landau-Ginzburg model, + +there are other symmetries +that get broken. + +And things for which +we didn't discuss + +what the corresponding +statistical field theory is. + +A commonly used case +pertains to something + +that's called a Potts model. + +Where at each side +you have a variable, + +let's call it SI, +that takes q values, + +one, two, three, +all the way to q. + +And I can write +what would appear + +in the exponent +minus beta h to be + +a sum over nearest neighbors. + +And I can give some kind of +an interaction parameter here, + +but a delta si sj. + +So basically, what it says is +that on each side of a lattice, + +you put a number. + +Could be one, two, +three, up to q. + +And if two neighbors are +the same, they like it, + +and they gain some +kind of a weight. + +That is, if k is positive, +encourages that to happen. + +If the two neighbors +are different, + +then it doesn't matter. + +You don't gain energy, +but you don't really + +care as to which one it is. + +The underlying symmetry that +this has is permutation. + +Basically, if you were to +permute all of these indices + +consistently across the +lattice in any particular way, + +the energy would not change. + +So permutation symmetry +is what underlies this. + +And again, if I look at the +case of two, then at each side, + +let's say I have one or two. + +And one one and two two are +things that gain energy. + +One two or two one don't. + +Clearly it is the same +as the Ising model. + +So q equals to two is another +way of writing the Ising model. + +Q equals to three is something +that we haven't seen. + +So at each site, there +are three possibilities. + +Actually, when I started at MIT +as a graduate student in 1979, + +the project that I had +to do related to the q + +equals to three Potts model. + +Where did it come from? + +Well, at that time, +people were looking + +at surface of graphite, +which as you know, + +has this hexagonal structure. + +And then you can +absorb molecules + +on top of that, such as, +for example, krypton. + +And krypton would +want to come and sit + +in the center of one +of these hexagons. + +But its size was such +that once it sat there, + +you couldn't occupy +any of these sides. + +So the next one would have +to go, let's say, over here. + +Now, it is possible to +subdivide this set of hexagons + +into three sub lattices. + +One, two, three, one, +two, three, et cetera. + +Actually, I drew +this one incorrectly. + +It would be sitting here. + +And what happens is that +basically the agile particles + +would order by occupying one of +three equivalent sublattices. + +So the way that that order +got destroyed was then + +described by the q equals to +three Potts universality class. + +You can think of +something like q + +equals to four that would +have a symmetry of a tetragon. + +And so some structure that +is like a tetragon getting, + +let's say, distorted in +some particular direction + +would then have four equivalent +directions, et cetera. + +So there's a whole set of other +types of universality classes + +and symmetry breakings that +we did not discuss before. + +And I just want +to emphasize that + +what we discussed before does +not cover all possible symmetry + +breakings. + +It was just supposed to +show you an important class + +and the technology +to deal with that. + +But again, in this +particular system, + +let's say you really wanted +to know at what temperature + +the phase transition occurs, +as well as what potential phase + +diagrams and +critical behavior is. + +And then you would +say, well, even + +if I could construct a +statistical field theory + +and analyze it in +two dimensions, + +and we've seen how +hard it is to go + +below some other +critical dimension, + +it doesn't tell me things about +phase diagrams, et cetera. + +So maybe trying to understand +and deal with this lattice + +model itself would tell +us more information. + +Although about quantities that +are not necessarily inverse. + +Depending on your +microscopic model, + +you may try to introduce +more complicated systems, + +such as inspired by quantum +mechanics, you can think + +of something that +I'll call a spin S + +model in which your SI +takes values from minus s, + +minus s plus 1, all +the way to plus s. + +There's 2s plus 1 possibilities. + +And you can think of this +as components of, say, + +a quantum spin of s +along the zed axis. + +Write some kind of +Hamiltonian for this. + +But as long as you deal +with things classically, + +it turns out that +this kind of system + +will not really have different +universality from the Ising + +model. + +So let's say we have +this lattice model. + +Then what can we do? + +So in the next +set of lectures, I + +will describe some tools for +dealing with these models. + +One set of approaches, the +one that we will start today, + +has to do with the position +space renormalization group. + +That is the approach +that we were following + +for renormalization previously. + +Dealt with going +to Fourier space. + +We had this sphere, +hyper sphere. + +And then we were basically +eliminating modes + +at the edge of this +sphere in Fourier space. + +We started actually by +describing the process + +in real space. + +So we will see +that in some cases, + +it is possible to do a +renormalization group directly + +on these lattice models. + +Second thing is, it turns out +that as combinatorial problems, + +some, but a very small +subset of these models, + +are susceptible to +exact solutions. + +Turns out that practically +all models in one dimension, + +as we will start today, +one can solve exactly. + +But there's one +prominent case, which + +is the two dimensionalizing +model that one can also + +solve exactly. + +And it's a very +interesting solution + +that we will also examine in, I +don't know, a couple of weeks. + +Finally, there are +approximate schemes + +that people have evolved for +studying these problems, where + +you have series expansions +starting from limits, where + +you know what is happening. + +And one simple +example would be to go + +to very high temperatures. + +And at high temperatures, +essentially every degree + +of freedom does what it wants. + +So it's essentially a +zero dimensional problem + +that you can solve. + +And then you can start treating +interactions perturbatively. + +So this is kind of +similar to the expansions + +that we had developed in 8 +333, the virial expansions, + +et cetera, about +the ideal gas limit. + +But now done on a system +that is a lattice, + +and going to +sufficiently high order + +that you can say something +about the phase transition. + +There is another extreme. + +In these systems, typically +the zero temperature state + +is trivial. + +It is perfectly ordered. + +Let's say all the +spins are aligned. + +And then you can start +expanding in excitations + +around that state and +see whether eventually, + +by including more +and more excitations, + +you can see the phase transition +out of the ordered state. + +And something that is actually +probably the most common use + +of these models, but I +won't cover in class, + +is to put them on the computer +and do some kind of a Monte + +Carlo simulation, +which is essentially + +a numerical way of trying to +generate configurations that + +are governed by this weight. + +And by changing the temperature +as it appears in that weight, + +whether or not one can, +in the simulation, see + +the phase transition happen. + +So that's the change +in perspective + +that I want you to have. + +So the first thing +that we're going to do + +is to do the number one here, +to do the position space + +renormalization group of +one dimensional Ising model. + +And the procedure that +I describe for you + +is sufficiently general +that in fact you + +can apply to any other +one dimensional model, + +as long as you only have these +nearest neighbor interactions. + +So here you have a lattice +that is one dimensional. + +So you have a set +of sites one, two. + +At some point, you have i, +i minus one, i plus one. + +Let's say we call +the last one n. + +So there are n sites. + +There are going to be 2 to +the n possible configurations. + +And your task is given +that at each site, + +there's a variable +that is binary. + +You want to calculate a +partition function, which + +is a sum over all these 2 +to the n configurations. + +Of a weight that is +this e to the sum + +over i B, the interaction +that couples SI and SI plus 1. + +Maybe I should have +called this e hat. + +And B is the thing that has +minus beta absorbed in it. + +So notice that basically, the +way that I have written it, + +one is interacting with two. + +i minus one is +interacting with i. + +i is interacting +with i plus one. + +So I wrote the nearest +neighbor interaction + +in this particular fashion. + +We may or may not worry +about the last spin, + +whether I want to +finish the series here, + +or sometimes I will use +periodic boundary condition + +and bring it back and couple +it to the first one, where + +I have a ring. + +So that's another possibility. + +Doesn't really matter all +that much at this stage. + +So this runs for i +going from one to n. + +There are n degrees of freedom. + +Now, renormalization +group is a procedure + +by which I get rid of +some degrees of freedom. + +So previously, I have +emphasized that what we did + +was some kind of an averaging. + +So we said that +let's say I could + +do some averaging of +three sites and call + +some kind of a representative +of those three. + +Let's say that we +want to do a RG + +by a factor of b equals to two. + +So then maybe you say that +I will pick sigma i prime + +and u sigma i to be sigma i +plus sigma i plus 1 over 2, + +doing some kind of an average. + +The problem with this choice +is that if the two spins are + +both pluses, I will get plus. + +If they're both minuses, +I will get minus. + +If there is one plus and +one minus, I will get zero. + +Why that is not +nice is that that + +changes the structure +of the theory. + +So I started with +binary variables. + +I do this rescaling. + +If I choose this scheme, I will +have three variables per site. + +But I can insist upon keeping +two variables per site, as long + +as I do everything +consistently and precisely. + +So maybe I can say that +when this occurs, where + +the two sites are different, +and the average would be zero, + +I choose as tiebreaker +the left one. + +So then I will +have plus or minus. + +Now you can convince +yourself that if I do this, + +and I choose always the +left one as tiebreaker, + +the story is the same as +just keeping the left one. + +So essentially, this kind of +averaging with a tiebreaker + +is equivalent to getting +rid of every other spin. + +And so essentially +what I can do is + +to say that I call +a sigma i prime. + +Now, in the new listing that I +have, this thing is no longer, + +let's say, the tenth one. + +It becomes the fifth one because +I removed half of things. + +So sigma i prime is +really sigma 2i minus 1. + +So basically, all the odd ones +I will call to be my new spins. + +All the even ones I want to +get rid of, I'll call them SI. + +So this is just a +renaming of the variables. + +I did some handwaving +to justify. + +Effectivity, all I did +was I broke this sum + +into two sets of sums, but +I call sigma i prime and SI. + +And each one of +them the index i, + +rather than running from +1 to n in this new set, + +the index i runs +from 1 to n over 2. + +So what I have said, +agian, is very trivial. + +I've said that the +original sum, I + +bring over as a sum over +the odd spin, whose names + +I have changed, and a +sum over even spins, + +whose names I have called SI. + +And I have an interaction, +which I can write as sum over i, + +essentially running +from 1 to n over 2. + +I start with the interaction +that involves sigma i + +prime with si because +now each sigma i + +prime is acting with +an s on one side. + +And then there's +another interaction, + +which is SI, and the next. + +So essentially, I rename +things, and I regrouped bonds. + +And the sum that was n terms +now n over 2 pairs of terms. + +Nothing significant. + +But the point is +that over here, I + +can rewrite this as a +sum over sigma i prime. + +And this is a product over +terms where within each term, + +I can sum over the spin that +is sitting between two spins + +that I'm keeping. + +So I'm getting rid of this spin +that sits between spin sigma + +i prime and sigma +i plus 1 prime. + +Now, once I perform +this sum over SI here, + +then what I will +get is some function + +that depends on sigma i prime +and sigma i plus 1 prime. + +And I can choose to +write that function as e + +to the b prime sigma i +prime sigma i plus 1 prime. + +And hence, the +partition function + +after removing every +other spin is the same + +as the partition function that +I have for the remaining spins + +weighted with this b prime. + +So you can see that I took the +original partition function + +and recast it in +precisely the same form + +after removing half of +the degrees of freedom. + +Now, the original b +for the Ising model + +is going to be parameterized +by g, h, and k. + +So the b prime I +did parameterize. + +So this, let's say, emphasizes +parameterized by g, h, k. + +I can similarly +parameterize this + +by g prime, h prime, k prime. + +And how do I know that? + +Because when I was +writing this, I + +emphasized that this is +the most general form + +that I can write down. + +There is nothing else +other than this form + +that I can write down for this. + +So what I have essentially is +that this e to the b prime, + +which is e to the g prime plus +h prime sigma i prime plus sigma + +i plus 1 prime plus k +prime sigma i prime sigma + +i plus 1 prime involves +these three parameters, + +is obtained by summing over SI. + +Let me just call it s being +minus plus 1 of e to the g plus + +h sigma 1 sigma i prime plus +SI plus k sigma i prime SI + +plus g plus kh sigma SI plus +sigma i plus 1 prime plus k SI + +sigma i plus 1. + +So it's an implicit +equation that + +relates g prime, h prime, +k prime, to g, h, and k. + +And in particular, just +to make the writing + +of this thing explicit more +clearly, I will give names. + +I will call e to the k to +the x, e to the h to by, + +e to the g to bz. + +And here, similarly, +I will write x prime e + +to the k prime, y +prime e to the h prime, + +and z prime is e to the g prime. + +So now I just have +to make a table. + +I have sigma i prime +sigma i plus 1 prime. + +And here also I can +have values of s. + +And the simplest possibility +here is I have plus plus. + +Actually, let's put +this number further out. + +So if both the sigma +primes are plus, + +what do I have on +the left hand side? + +I have e to the g +prime, which is z prime. + +e to the 2h prime, which +is y prime squared. + +e to the k prime, +which is x prime. + +What do I have on +the left hand side? + +On the left hand side, I +have two possible things + +that I can put. + +I can put s to be either +plus or s to be minus, + +and I have to sum over +those two possibilities. + +You can see that in all +cases, I have e to the 2g. + +That's a trivial thing. + +So I will always +have a z squared. + +Irrespective of s, I +have two factors of e + +to the h sigma prime. + +OK, you know what happened? + +I should've used-- +since I was using + +b, this factor of h over 2. + +So I really should have +put here an h prime over 2, + +and I should have +put here an h over 2 + +and h over 2 because the field +that was residing on the sites, + +I am dividing half of it +to the right and half of it + +to the left bond. + +And since I'm writing things +in terms of the bonds, + +that's how I should go. + +So what I have here actually +is now one factor of i prime. + +That's better. + +Now, what I have on +the right is similarly + +one factor of y +from the h's that + +go with sigma 1 +prime, sigma 2 prime. + +And then if s is +plus, then you can + +see that I will get two +factors of e to the k + +because both bonds +will be satisfied. + +Both bonds will be plus plus. + +So I will get x squared, +and the contribution + +to the h of the +intermediate bond s + +is going to be 1e to the h. + +So I will get x squared y. + +Whereas if I put it the +intermediate sign for s + +to be minus 1, then I have +two pluses at the end. + +The one in the middle is minus. + +So I would have two +dissatisfied factors of e + +to the k becoming +e to the minus k. + +So it's x to the minus 2. + +And the field also +will give a factor of e + +to the minus h or y inverse. + +So there are four +possibilities here. + +The next one is minus minus. + +z prime will stay the way it is. + +The field has switched sign. + +So this becomes y prime inverse. + +But since both of them +are minus-- minus, + +minus-- the k factor +is satisfied and happy. + +Gives me x prime because +it's e to the plus k. + +On the right hand side, I +will always get the z squared. + +The first factor +becomes the inverse. + +Now, s plus 1 is a +plus site, plus spin, + +that is sandwiched +between two minus spins. + +So there are two unhappy bonds. + +This gives me x to the minus 2. + +Why the spin is pointing in +the direction of the field. + +So there's the y here. + +And here I will get x +squared and y inverse + +because now I have +three negative signs. + +So all the k's are happy. + +There's the next one, +which is plus and minus. + +Plus and minus, we can see that +the contribution to the field + +vanishes. + +Because sigma i prime and plus +sigma i plus 1 prime are zero. + +I will still get z, +the contribution, + +because plus and minus, +the bond between them + +gives me e to the minus k prime. + +I have here z squared. + +There is no overall contribution +of y for the same reason + +that there was nothing here. + +But from s, I will get a +factor of y plus y inverse. + +And there's no +contribution for x + +because I have a +plus and a minus. + +And if the spin is either +plus or minus in the middle, + +there will be one satisfied +and one dissatisfied bond. + +Again, by symmetry, +the other configuration + +is exactly the same. + +So while I had four +configuration, and hence + +four things to match, the +last two are the same. + +And that's consistent +with my having + +three variables, x prime, y +prime, and z prime, to solve. + +So there are three equations +and three variables. + +Now, to solve these equations, +we can do several things. + +Let's, for example, multiply +all four equations together. + +What do we get on +the left hand side? + +There are two x's, two +inverse x's, y, and inverse y, + +but four factors of z. + +So I get z prime to +the fourth factor. + +On the other side, I +will get z to the eight, + +and then the product +of those four factors. + +I can divide one, equation +one, by equation two. + +What do I get? + +The x's cancel. + +The x's cancel. + +So I will get y prime squared. + +On the other side, +divide these two. + +I will get y squared. + +x squared y plus x +squared y inverse, + +x minus 2y plus x2 minus-- +yeah, x2 y inverse. + +And finally, to get the equation +for x prime, what I can do + +is I can multiply 1 and +2, divide by 3 and 4. + +And if I do that, on +the left hand side + +I will get x prime +to the fourth. + +And on the right +hand side, I will + +get x squared y plus x +to the minus 2 y inverse + +x minus 2y x squared y inverse +divided by y plus y inverse + +squared. + +So I can take the log of +these equations, if you like, + +to get the recurrence +relations for the parameters. + +For example, taking the +log of that equation, + +you can see that I +will get g prime. + +From here, I would get +2g plus some function. + +There's some delta g +that depends on k and h. + +If I do the same +thing here, you can + +see that I will +get an h prime that + +is h plus some function +from the log of this + +that depends on k and h. + +And finally, I will get k +prime some function of k and h. + +This parameter g is +not that important. + +It's basically an +overall constant. + +The way that we started +it, we certainly + +don't expect it to modify +phase diagrams, et cetera. + +And you can see that it never +affects the equations that + +govern h and k, the +two parameters that + +give the relative weight of +different configurations. + +Whether you are in a ferromagnet +or a disordered state + +is governed by these +two parameters. + +And indeed, we can ignore this. + +Essentially, what it amounts to +is as follows, that every time + +I remove some of the +spins, I gradually + +build a contribution +to my free energy. + +Because clearly, once +I have integrated out + +over all of the energies, what I +will have will be the partition + +function. + +Its log would be +the free energy. + +And actually, we encountered +exactly the same thing + +when we were doing +momentum space RG. + +There was always, as a +result of the integration, + +some contribution that I +call delta f that I never + +looked at because, OK, it's +part of the free energy + +but does not govern +the relative weights + +of the different configurations. + +So these are really +the two things + +that we need to focus on. + +Now, if we did things +correctly and these + +are correct equations, had +I started in the subspace + +where h equals to zero, +which had up-down symmetries, + +I could have changed all of +my sigmas to minus sigma, + +and for h equals to zero, the +energy would not have changed. + +So a check that we +did things correctly + +is that if h equals to zero, +then h prime has to be zero. + +So let's see. + +If h equals to zero +or y is equal to one, + +well if y is equal +to one, you can + +see that those two factors in +the numerator and denominator + +are exactly the same. + +And so y prime stays to one. + +So this check has +been performed. + +So if I am on h equals to +zero on the subspace that + +has symmetry, then I have only +one parameter, this k or x. + +And so on this space, the +recursion relation that I have + +is that x prime +to the fourth is x + +squared plus x to +the minus 2 squared. + +I think I made a mistake here. + +No, it's correct. + +y plus y inverse. + +OK, but y is one. + +So this is divided by +2 squared, which is 4. + +But let me double check +so that I don't go-- yeah. + +So this is correct. + +So I can write it in terms +of x being e to the k. + +So what I have here +is e to the 4k prime. + +I have here e to the 2k plus e +to the minus 2k divided by 2, + +which is hyperbolic +cosine of 2k, squared. + +So what I will get is k +prime is 1/2 log hyperbolic + +cosine of 2k. + +Now, k is a parameter +that we are changing. + +As we make k stronger, +presumably things + +are more coupled to each +other and should go more + +towards order. + +As k goes towards zero, +basically the spins + +are independent. + +They can do whatever they like. + +So it kind of makes +sense that there + +should be a fixed point at +zero corresponding to zero + +correlation length. + +And let's check that. + +So if k is going to zero-- +it's very small-- then + +k prime is 1/2 log hyperbolic +cosine of a small number, + +is roughly 1 plus that +small number squared over 2. + +There's a series like that. + +Log of 1 plus a small +number is a small number. + +So this becomes 4k +squared over 2 over 2. + +It's k squared. + +So it says that if I, let's say, +start with a k that is 1/10, + +my k prime would be +1/100 and then 1/10,000. + +So basically, this +is a fixed point + +that attracts everything to it. + +Essentially, what +it says is you may + +have some weak +amount of coupling. + +As you go and look at the spins +that are further and further + +apart, the effective coupling +between them is going to zero. + +And the spins that +are further apart + +don't care about each other. + +They do whatever they like. + +So that all makes +physical sense. + +Well, we are really +interested in this other end. + +What happens at k +going to infinity? + +We can kind of look +at this equation. + +Or actually, look at this +equation, also doesn't matter. + +But here, maybe it's clearer. + +So I have e to the 4k prime. + +And this is going to +be dominated by this. + +This is e to the 2k. + +e to the minus 2k is very small. + +So it's going to +be approximately + +e to the 4k divided by 4. + +So what I have out here +is that k is very large. + +k prime is roughly +k, but then smaller + +by a factor that +is 1/2 of log 2. + +So we try to take two spins that +are next to each other, couple + +them with a very strong k. + +Let's say a million, +10 million, whatever. + +And then I look at spins +that are too further apart. + +They're still very strongly +coupled, but slightly less. + +It's a million minus log 2. + +So it very, very gradually +starts to move away from here. + +But then as it kind of goes +further, it kind of speeds up. + +What it says is that it is true. + +At infinity, you +have a fixed point. + +But that fixed +point is unstable. + +And even if you have very +strong but finite coupling, + +because things are finite, as +you go further and further out, + +the spins become less +and less correlated. + +This, again, is another +indication of the statement + +that a one dimensional +system will not order. + +So one thing that you +can do to sort of make + +this look slightly better, since +we have the interval from zero + +to infinity, is to +change variables. + +I can ask what does +tang of k prime do? + +So tang k prime is e to the +2k prime minus 1 divided by + +e to the 2k prime plus 1. + +You write e to the 2k's +in terms of this variable. + +At the end of the day, +a little bit of algebra, + +you can convince yourself +that the recursion relation + +for tang k has a +very simple form. + +The new tang k is simply the +square of the old tang k. + +If I plot things as +a function of tang k + +that runs between zero +and one, that fixed point + +that was at infinity +gets mapped into one, + +and the flow is +always towards here. + +There is no other +fixed point in between. + +Previously, it wasn't +clear from the way + +that I had written whether +potentially there's + +other fixed points +along the k-axis. + +If you write it as t +prime tang is t squared, + +where t stands for tang, +clearly the only fixed points + +are at zero and one. + +But now this also +allows us to ask + +what happens if +you also introduce + +the field direction, +h, in this space. + +Now, one thing to +check is that if you + +start with k equals to zero, +that is independent spins, + +you look at the equation here. + +k equals to 0 corresponds +to x equals to one. + +This factor drops out. + +You see y prime is equal to y. + +So if you have no +coupling, there + +is no reason why the +magnetic field should change. + +So essentially, this entire line +corresponds to fixed points. + +Every point here +is a fixed point. + +And we can show +that, essentially, + +if you start along +field zero, you go here. + +If you start along different +values of the field, + +you basically go to +someplace along this line. + +And all of these flows +originate, if you go and plot + +them, from back here +at this fixed point + +that we identified before +at h equals to zero. + +So in order to find out what is +happening along that direction, + +all we need to do is to go and +look at x going to infinity. + +With x going to +infinity, you can + +see that y prime squared, the +equation that we have for y, + +y prime squared is y squared. + +And then there's this fraction. + +Clearly, the terms that are +proportional to x squared + +will overwhelm +those proportional + +to x to the minus 2. + +So I will get a +y and a y inverse + +from the numerator +and denominator. + +And so this goes +like y to the fourth. + +Which means that in the vicinity +of this point, what you have is + +that h prime is 2h. + +So this, again, is +irrelevant direction. + +And here, you are flowing +in this direction. + +And the combination +of these two really + +justifies the kind of flows +that I had shown you before. + +So essentially, in the +one dimensional model, + +you can start with any +microscopic set of k and h's + +that you want. + +As you rescale, you essentially +go to independent spins + +with an effective +magnetic field. + +So let's say we start with +very close to this fixed point. + +So we had a very +large value of k. + +I expect if I have +a large value of k, + +neighboring spins are +really close to each other. + +I have to go very far before, +if I have a patch of pluses, + +I can go over to a +patch of minuses. + +So there's a large +correlation length + +in the vicinity of this point. + +And that correlation +length is a function + +of our parameters k and h. + +Now, the point is that +the recursion relation + +that I have for k does not look +like the type of recursions + +that I had before. + +This one is fine because I can +think of this as my usual h + +prime is b to the yh h, where +here I'm clearly dealing + +with a b equals to two, and so +I can read off my yh to be one. + +But the recursion +relation that I have for k + +is not of that form. + +But who said that I +choose k as the variable + +that I put over here? + +I have been doing all of +these manipulations going + +from k to x, et cetera. + +One thing that behaves +nicely, you can see, + +is a variable if I +call e to the minus k + +prime is square root +of 2 e to the minus k. + +At k equals to infinity, +this is something + +that goes to zero on both ends. + +But if its k is +large but not finite, + +it says that on +the rescaling, it + +changes by a factor of root 2. + +So if I say, well, +what is c as a function + +of the magnetic field, +rather than writing k, + +I will write it as +e to the minus k. + +It's just another way +of writing things. + +Well, I know that under +one step of RG, all + +my length scales have +shrunk by a factor of two. + +So this is twice the c that +I should write down with 2h + +and root 2 e to the minus k. + +So I just related the +correlation length + +before and after one +step of RG, starting + +from very close to this point. + +And for these two +factors, 2 and root 2, + +I use the results that +I have over there. + +And this I can keep doing. + +I can keep iterating this. + +After l steps of +RG, this becomes 2 + +to the l, c of 2 +to the lh, and 2 + +to the l over 2 +e to the minus k. + +I iterate this sufficiently +so that I have moved away + +from this fixed point, where +everything is very strongly + +correlated. + +And so that means +I move, let's say, + +until this number is something +that is of the order of one. + +Could be 2. + +Could be 1/2. + +I really don't care. + +But the number of +iterations, the number + +of rescalings by a +factor of two that I + +have to do in order to achieve +this, is when 2 to the l + +is of the order of e to the k. + +e to the 2k, sorry. + +And if I do that, I +find that c should + +be e to the 2k some +function of h e to the 2k. + +So let's say I am +at h equals to zero. + +And I make the strength of the +interaction between neighbors + +stronger and stronger. + +If I asked you, how does +the correlation length, + +how does the size of the patches +that are all plus and minus + +change as k becomes +stronger and stronger? + +Well, RG tells you that +it goes in this fashion. + +In the problem +set that you have, + +you will solve the problem +exactly by a different method + +and get exactly this form. + +What else? + +Well, we said that one of the +characteristics of a system + +is that the free +energy has a singular + +part as a function +of the variables + +that we have that is related +to the correlation length + +to the power d. + +In this case, we +have d equals to one. + +So the statement is +that the singular part + +of the free energy, as you +approach infinite coupling + +strength, behaves +as e to the minus 2k + +some other function +of h, e to the 2k. + +Once you have a +function such as this, + +you can take two +derivatives with respect + +to the field to get +the susceptibility. + +So the susceptibility would +go like two derivatives + +of the free energy with +respect to the field. + +You can see that each derivative +brings forth a factor of e + +to the 2k. + +So two derivatives will bring +a factor of e to the 2k, + +if I evaluate it at +h equals to zero. + +So the statement is that +if I'm at zero field, + +and I put on a small +infinitesimal magnetic field, + +it tends to overturn +all of the spins + +in the direction of the field. + +And the further you are +close to k to infinity, + +there are larger responses +that you would see. + +The susceptibility +of the response + +diverges as k goes to infinity. + +So in some sense, this model +does not have phase transition, + +but it demonstrates some +signatures of the phase + +transition, such as +diverging correlation length + +and diverging +susceptibility if you + +go to very, very strong +nearest neighbor coupling. + +There is one other +relationship that we had. + +That is, the susceptibility +is an integral + +in d dimension over +the correlation length, + +which we could say +in one dimension-- + +well, actually, let's +write it in d dimension. + +e to the minus x +over c divided by x. + +We introduce an exponent, +eta, to describe + +the decay of correlations. + +So this would generally behave +like c to the 2 minus eta. + +Now, in this case, we see that +both the correlation length + +and susceptibility diverge with +the same behavior, e to the 2k. + +They're proportional +to each other. + +So that immediately +tells me that for the one + +dimensional system +that we are looking at, + +eta is equal to one. + +And if I substitute back +here, so eta is one, + +the dimension is one, +and the two cancels. + +Essentially, it says that +the correlation length + +in one dimension have a +pure exponential decay. + +They don't have this +sub leading power load + +that you would have +in higher dimensions. + +So when you do +things exactly, you + +will also be able +to verify that. + +So all of the predictions +of this position space + +RG method that we can carry out +in this one dimensional example + +very easily, you can +also calculate and obtain + +through the method that +is called transfer matrix, + +and is the subject +of the problem set + +that was posted yesterday. + +Also, you can see that +this approach will + +work for any system +in one dimension. + +All I really need to ensure is +that the b that I write down + +is sufficiently +general to include + +all possible interactions that +I can write between two spins. + +Because if I have some +subset of those interactions, + +and then I do this procedure +that I have over here + +and then take the +log, there's no reason + +why that would not +generate all things that + +are consistent with symmetry. + +So you really have to +put all possible terms, + +and then you will get +all possible terms here, + +and there would be a recursion +relation that would relate. + +You can do this very easily, for +example, for the Potts model. + +For the continuous spin systems, +it becomes more difficult. + +Now let's say briefly as to why +we can solve things exactly, + +let's say, for the one +dimensionalizing model + +by this procedure. + +But this procedure we cannot +do in higher dimensions. + +So let's, for example, think +that we have a square lattice. + +Just generalize what we +had to two dimensions. + +And let's say that we want +to eliminate this spin + +and-- well, let's see, +what's the best way? + +Yeah, we want to eliminate +a checkerboard of spins. + +So we want to eliminate +half of the spins. + +Let's say the white +squares on a checkerboard. + +And if I were to eliminate these +spins, like I did over here, + +I should be able to +generate interactions + +among spins that are left over. + +So you say, fine. + +Let's pick these four spins. + +Sigma 1, sigma 2, +sigma 3, sigma 4, + +that are connected +to this spin, s, + +that is sitting in the middle, +that I have to eliminate. + +So let's also stay +in the space where + +h equals to zero, +just for simplicity. + +So the result of +eliminating that is + +I have to do a sum over s. + +I have e to the-- let's say +the original interaction is k, + +and s is coupled by these bonds +to sigma 1, sigma 2, sigma 3, + +sigma 4. + +Now, summing over the +two possible values of s + +is very simple. + +It just gives me e to +the k times the sum plus + +e to the minus k, that sum. + +So it's the same thing as 2 +hyperbolic cosine of k, sigma + +1 plus sigma 2 plus +sigma 3 plus sigma 4. + +We say good. + +I had something like +that, and I took a log + +so that I got the k prime. + +So maybe I'll do something +like a recasting of this, + +and maybe a recasting of this +will give me some constant, + +will give me some +kind of a k prime, + +and then I will have sigma +1, sigma 2, sigma 2, sigma 3, + +sigma 3, sigma 4, +sigma 4, sigma 1. + +But you immediately see that +that cannot be the entire + +story. + +Because there is really +no ordering among sigma 1, + +sigma 2, sigma 3, sigma 4. + +So clearly, because of +the symmetries of this, + +you will generate also sigma 1 +sigma 3 plus sigma 2 sigma 4. + +That is, eliminating this +spin will generate for you + +interactions among +these, but also + +interactions that go like this. + +And in fact, if you +do it carefully, + +you'll find that you will also +generate an interaction that + +is product of all four spins. + +You will generate something +that involves all of the force. + +So basically, because +of the way of geometry, + +et cetera, that you have +in higher dimensions, + +there is no trick that +is analogous to what + +we could do in one dimension +where you would eliminate + +some subset of spins and not +generate longer and longer + +range interactions, interactions +that you did not have. + +You could say, OK, I +will start including + +all of these +interactions and then + +have a higher, larger +parameter space. + +But then you do +something else, you'll + +find that you need to +include further and further + +neighboring interactions. + +So unless you do some kind of +termination or approximation, + +which we will do +next time, then there + +is no way to do this exactly +in higher dimensions. + +AUDIENCE: Question. + +PROFESSOR: Yes. + +AUDIENCE: I mean, are you +putting any sort of weight + +on the fact that, for +example, sigma 1 and sigma 3 + +are farther apart than +sigma 1 and sigma 2, + +or are we using taxi cab +distances on this lattice? + +PROFESSOR: Well, we are +thinking of an original model + +that we would like +to solve, in which + +I have specified that +things are coupled only + +to nearest neighbors. + +So the ones that correspond +to sigma 1, sigma 3, + +are next nearest neighbors. + +They're certainly farther +apart on the lattice. + +You could say, well, +there's some justification, + +if these are ions +and they have spins, + +to have some weaker interaction +that goes across here. + +There has to be some +notion of space. + +I don't want to couple everybody +to everybody else equivalently. + +But if I include this, +then I have further more + +complicated Hamiltonian. + +And when I do RG, +I will generate + +an even more +complicated Hamiltonian. + +Yes. + +AUDIENCE: [INAUDIBLE]. + +PROFESSOR: Question is, suppose +I have a square lattice. + +Let's go here. + +And the suggestion +is, why don't I + +eliminate all of +the spins over here, + +maybe all of the +spins over here? + +So the problem is that I +will generate interactions + +that not only go like this, but +interactions that go like this. + +So the idea of what happens is +that imagine that there's these + +spins that you're eliminating. + +As long as there's paths that +connect the spins that you're + +eliminating to any +other spin, you + +will generate that +kind of couple. + +Again, the reason that the +one dimensional model works + +is also related to +its exact solvability + +by this transfer matrix method. + +So I will briefly mention +that in the last five minutes. + +So for one dimensional +models, the partition function + +is a sum over whatever +degree of freedom you have. + +Could be Ising, Potts, +xy, doesn't matter. + +But the point is +that the interaction + +is a sum of bonds that connect +one site to the next site. + +I can write this as a product of +e to the b of SI and SI plus 1. + +Now, I can regard +this entity-- let's + +say I have the Potts +model q values. + +This is q possible values. + +This is q possible values. + +So there are q squared possible +values of the interaction. + +And there is q squared +possible values + +of this Boltzmann weight. + +I can regard that +as a matrix, but I + +can write in this fashion. + +And so what you +have over there, you + +can see is effectively you have +s1, ts2, s2, ts3, and so forth. + +And if I use periodic boundary +condition like the one + +that I indicated there so +that the last one is connected + +to the first one, and then I +do a sum over all of these s's, + +this is just the +product of two matrices. + +So this is going to become, when +I sum over s2, s1 t squared s3 + +and so forth. + +You can see that +the end result is + +trace of the matrix t +raised to the power of n. + +Now, the trace you can +calculate in any representation + +of the matrix. + +If you manage to find +the representation where + +t is diagonal, then +the trace would + +be sum over alpha +lambda alpha to the n, + +where these lambdas are the +eigenvalues of this matrix. + +And if n is very large, +the thermodynamic + +limit that we are +interested, it will + +be dominated by the +largest eigenvalue. + +Now, if I write this for +something like Potts model + +or any of the spin models that +I had indicated over there, + +you can see that all +elements of this matrix + +being these Boltzmann +weights are plus, positive. + +Now, there's a theorem called +Frobenius's theorem, which + +states that if you have a +matrix, all of its eigenvalues + +are positive, then the largest +eigenvalues is non-degenerate. + +So what that means is that if +this matrix is characterized + +by a set of parameters, like +our k's, et cetera, and I + +change that parameter, +k, well the eigenvalue + +is obtained by looking +at a single matrix. + +It doesn't know +anything about that. + +The only way that the +eigenvalue can become singular + +is if two eigenvalues +cross each other. + +And since Frobenius's +theorem does not allow that, + +you conclude that this +largest eigenvalue + +has to be a perfectly nice +analytical function of all + +of the parameters that go into +constructing this Hamiltonian. + +And that's a mathematical way +of saying that there is no phase + +transition for one dimensional +model because you cannot have + +a crossing of eigenvalues, and +there is no singularity that + +can take place. + +Now, an interesting then +question or caveat to that + +comes from the very question +that was asked over here. + +What if I have, let's say, +a two dimensional model, + +and I regard it essentially +as a complicated one + +dimensional model in +which I have a complicated + +multi-variable +thing over one side, + +and then I can go through this +exact same procedure over here + +also? + +And then I would have to +diagonalize this huge matrix. + +So if this is l, it would be a +2 to the l by 2 to the l matrix. + +And you may naively +think that, again, + +according to +Frobenius's theorem, + +there should be no +phase transition. + +Now, this is exactly what +Lars Onsager did in order + +to solve the two +dimensionalizing model. + +He constructed this matrix +and was clever enough + +to diagonalize it and show +that in the limit of l going + +to infinity, then the +Frobenius's theorem + +can and will be violated. + +And so that's something +that we will also + +discuss in some of +our future lectures. + +Yes. + +AUDIENCE: But it won't +be violated in the one + +dimensional case, even +if n goes to infinity? + +PROFESSOR: Yeah, because +n only appears over here. + +Lambda max is a perfectly +analytic function. \ No newline at end of file diff --git a/1eXWDepLpNU.txt b/1eXWDepLpNU.txt new file mode 100644 index 0000000000000000000000000000000000000000..e527f88bf6de1e2c900ede79c6f5eb706b10c66c --- /dev/null +++ b/1eXWDepLpNU.txt @@ -0,0 +1,11603 @@ +align:start position:0% + +okay so where were we last time we had + + align:start position:0% +okay so where were we last time we had + + + align:start position:0% +okay so where were we last time we had +started we had talked about started a + + align:start position:0% +started we had talked about started a + + + align:start position:0% +started we had talked about started a +general conversation about + + align:start position:0% +general conversation about + + + align:start position:0% +general conversation about +estimation and um we had seen a couple + + align:start position:0% +estimation and um we had seen a couple + + + align:start position:0% +estimation and um we had seen a couple +of different examples of estimators that + + align:start position:0% +of different examples of estimators that + + + align:start position:0% +of different examples of estimators that +seem to have kind of just like we just + + align:start position:0% +seem to have kind of just like we just + + + align:start position:0% +seem to have kind of just like we just +thought of them off the top of our head + + align:start position:0% +thought of them off the top of our head + + + align:start position:0% +thought of them off the top of our head +and both estimators remember this was uh + + align:start position:0% +and both estimators remember this was uh + + + align:start position:0% +and both estimators remember this was uh +we were estimating Theta in a zero in a + + align:start position:0% +we were estimating Theta in a zero in a + + + align:start position:0% +we were estimating Theta in a zero in a +uniform zero Theta distribution and both + + align:start position:0% +uniform zero Theta distribution and both + + + align:start position:0% +uniform zero Theta distribution and both +estimators seemed quite reasonable and + + align:start position:0% +estimators seemed quite reasonable and + + + align:start position:0% +estimators seemed quite reasonable and +so then the next obvious question is + + align:start position:0% +so then the next obvious question is + + + align:start position:0% +so then the next obvious question is +well how do we know which one to use how + + align:start position:0% +well how do we know which one to use how + + + align:start position:0% +well how do we know which one to use how +do we decide between estimators if we + + align:start position:0% +do we decide between estimators if we + + + align:start position:0% +do we decide between estimators if we +have more than one estimator available + + align:start position:0% +have more than one estimator available + + + align:start position:0% +have more than one estimator available +okay and last time we saw the first + + align:start position:0% +okay and last time we saw the first + + + align:start position:0% +okay and last time we saw the first +Criterion that that one might want to + + align:start position:0% +Criterion that that one might want to + + + align:start position:0% +Criterion that that one might want to +use to uh choose among estimators and + + align:start position:0% +use to uh choose among estimators and + + + align:start position:0% +use to uh choose among estimators and +that was unbiased unbiasedness okay so + + align:start position:0% +that was unbiased unbiasedness okay so + + + align:start position:0% +that was unbiased unbiasedness okay so +an estimator is unbiased for Theta if + + align:start position:0% +an estimator is unbiased for Theta if + + + align:start position:0% +an estimator is unbiased for Theta if +the expectation of the estimator is + + align:start position:0% +the expectation of the estimator is + + + align:start position:0% +the expectation of the estimator is +equal to the parameter we're trying to + + align:start position:0% +equal to the parameter we're trying to + + + align:start position:0% +equal to the parameter we're trying to +estimate for all values of the parameter + + align:start position:0% +estimate for all values of the parameter + + + align:start position:0% +estimate for all values of the parameter +all possible values of the parameter + + align:start position:0% +all possible values of the parameter + + + align:start position:0% +all possible values of the parameter +okay and then I drew a picture and I + + align:start position:0% +okay and then I drew a picture and I + + + align:start position:0% +okay and then I drew a picture and I +said that here is so remember an + + align:start position:0% +said that here is so remember an + + + align:start position:0% +said that here is so remember an +estimator is a function of random + + align:start position:0% +estimator is a function of random + + + align:start position:0% +estimator is a function of random +variables so it itself is a random Vari + + align:start position:0% +variables so it itself is a random Vari + + + align:start position:0% +variables so it itself is a random Vari +aable so it has a distribution so we can + + align:start position:0% +aable so it has a distribution so we can + + + align:start position:0% +aable so it has a distribution so we can +talk about characteristics of that + + align:start position:0% +talk about characteristics of that + + + align:start position:0% +talk about characteristics of that +distribution here is a particular + + align:start position:0% +distribution here is a particular + + + align:start position:0% +distribution here is a particular +distribution of an estimator Theta hat + + align:start position:0% +distribution of an estimator Theta hat + + + align:start position:0% +distribution of an estimator Theta hat +and this one I've drawn so that it's + + align:start position:0% +and this one I've drawn so that it's + + + align:start position:0% +and this one I've drawn so that it's +unbiased here's a particular + + align:start position:0% +unbiased here's a particular + + + align:start position:0% +unbiased here's a particular +distribution of a different Theta hat + + align:start position:0% +distribution of a different Theta hat + + + align:start position:0% +distribution of a different Theta hat +say and I've drawn it so it's biased + + align:start position:0% +say and I've drawn it so it's biased + + + align:start position:0% +say and I've drawn it so it's biased +okay so the expectation for that the + + align:start position:0% +okay so the expectation for that the + + + align:start position:0% +okay so the expectation for that the +second uh estimator over there is not + + align:start position:0% +second uh estimator over there is not + + + align:start position:0% +second uh estimator over there is not +equal to Theta so it's a biased + + align:start position:0% +equal to Theta so it's a biased + + + align:start position:0% +equal to Theta so it's a biased +estimator okay so let's see an example + + align:start position:0% +estimator okay so let's see an example + + + align:start position:0% +estimator okay so let's see an example +so we've seen this particular estimator + + align:start position:0% +so we've seen this particular estimator + + + align:start position:0% +so we've seen this particular estimator +before remember this is uh uniform the + + align:start position:0% +before remember this is uh uniform the + + + align:start position:0% +before remember this is uh uniform the +the random sample is uniform zero Theta + + align:start position:0% +the random sample is uniform zero Theta + + + align:start position:0% +the random sample is uniform zero Theta +and we came up with the idea that we + + align:start position:0% +and we came up with the idea that we + + + align:start position:0% +and we came up with the idea that we +could just get you know compute the + + align:start position:0% +could just get you know compute the + + + align:start position:0% +could just get you know compute the +sample mean from from that random sample + + align:start position:0% +sample mean from from that random sample + + + align:start position:0% +sample mean from from that random sample +multiply it by two and that would be a + + align:start position:0% +multiply it by two and that would be a + + + align:start position:0% +multiply it by two and that would be a +reasonable estimator for Theta hat or + + align:start position:0% +reasonable estimator for Theta hat or + + + align:start position:0% +reasonable estimator for Theta hat or +for Theta + + align:start position:0% +for Theta + + + align:start position:0% +for Theta +sorry um so let's see if this one is in + + align:start position:0% +sorry um so let's see if this one is in + + + align:start position:0% +sorry um so let's see if this one is in +fact biased or + + align:start position:0% +fact biased or + + + align:start position:0% +fact biased or +unbiased well we can just compute the + + align:start position:0% +unbiased well we can just compute the + + + align:start position:0% +unbiased well we can just compute the +expectation by using the properties of + + align:start position:0% +expectation by using the properties of + + + align:start position:0% +expectation by using the properties of +expectation that we saw a few lectures + + align:start position:0% +expectation that we saw a few lectures + + + align:start position:0% +expectation that we saw a few lectures +ago so we don't have to we don't have to + + align:start position:0% +ago so we don't have to we don't have to + + + align:start position:0% +ago so we don't have to we don't have to +sort of go back to the definition of + + align:start position:0% +sort of go back to the definition of + + + align:start position:0% +sort of go back to the definition of +expectation we just say well the + + align:start position:0% +expectation we just say well the + + + align:start position:0% +expectation we just say well the +expectation of theta hat is equal to by + + align:start position:0% +expectation of theta hat is equal to by + + + align:start position:0% +expectation of theta hat is equal to by +properties of expectation we can pull + + align:start position:0% +properties of expectation we can pull + + + align:start position:0% +properties of expectation we can pull +out the two and the 1 over n from the uh + + align:start position:0% +out the two and the 1 over n from the uh + + + align:start position:0% +out the two and the 1 over n from the uh +from the expectation and from the + + align:start position:0% +from the expectation and from the + + + align:start position:0% +from the expectation and from the +summation + + align:start position:0% +summation + + + align:start position:0% +summation +okay and then we put we plug in the uh + + align:start position:0% +okay and then we put we plug in the uh + + + align:start position:0% +okay and then we put we plug in the uh +the expectation of X subi which is just + + align:start position:0% +the expectation of X subi which is just + + + align:start position:0% +the expectation of X subi which is just +equal to Theta over 2 everyone knows + + align:start position:0% +equal to Theta over 2 everyone knows + + + align:start position:0% +equal to Theta over 2 everyone knows +where that came from right okay and then + + align:start position:0% +where that came from right okay and then + + + align:start position:0% +where that came from right okay and then +we just sort of do this summation and we + + align:start position:0% +we just sort of do this summation and we + + + align:start position:0% +we just sort of do this summation and we +get the twos cancel and we get that this + + align:start position:0% +get the twos cancel and we get that this + + + align:start position:0% +get the twos cancel and we get that this +is equal to Theta okay so unbiased + + align:start position:0% +is equal to Theta okay so unbiased + + + align:start position:0% +is equal to Theta okay so unbiased +estimator so that's a good thing + + align:start position:0% + + + + align:start position:0% + +right okay how about our other estimate + + align:start position:0% +right okay how about our other estimate + + + align:start position:0% +right okay how about our other estimate +so the other option that we had talked + + align:start position:0% +so the other option that we had talked + + + align:start position:0% +so the other option that we had talked +about was just using the nth order + + align:start position:0% +about was just using the nth order + + + align:start position:0% +about was just using the nth order +statistic and that also seemed + + align:start position:0% +statistic and that also seemed + + + align:start position:0% +statistic and that also seemed +reasonable right so let's see uh what we + + align:start position:0% +reasonable right so let's see uh what we + + + align:start position:0% +reasonable right so let's see uh what we +can say about whether this one is biased + + align:start position:0% +can say about whether this one is biased + + + align:start position:0% +can say about whether this one is biased +or unbiased any uh any + + align:start position:0% + + + + align:start position:0% + +guesses become more unbiased as you take + + align:start position:0% +guesses become more unbiased as you take + + + align:start position:0% +guesses become more unbiased as you take +as n + + align:start position:0% +as n + + + align:start position:0% +as n +increases so you you you have kind of + + align:start position:0% +increases so you you you have kind of + + + align:start position:0% +increases so you you you have kind of +the right intuition but you haven't + + align:start position:0% +the right intuition but you haven't + + + align:start position:0% +the right intuition but you haven't +expressed it in the right way so BAS + + align:start position:0% +expressed it in the right way so BAS + + + align:start position:0% +expressed it in the right way so BAS +basically what what's happening is that + + align:start position:0% +basically what what's happening is that + + + align:start position:0% +basically what what's happening is that +the it it it it will be biased we're + + align:start position:0% +the it it it it will be biased we're + + + align:start position:0% +the it it it it will be biased we're +going to see that and the amount of the + + align:start position:0% +going to see that and the amount of the + + + align:start position:0% +going to see that and the amount of the +bias is going to get smaller as in gets + + align:start position:0% +bias is going to get smaller as in gets + + + align:start position:0% +bias is going to get smaller as in gets +larger okay so and do you want to do you + + align:start position:0% +larger okay so and do you want to do you + + + align:start position:0% +larger okay so and do you want to do you +want to share your intuition for why + + align:start position:0% +want to share your intuition for why + + + align:start position:0% +want to share your intuition for why +it's biased we talked about it last time + + align:start position:0% +it's biased we talked about it last time + + + align:start position:0% +it's biased we talked about it last time +if you take more draws then the + + align:start position:0% +if you take more draws then the + + + align:start position:0% +if you take more draws then the +probability that the highest draws + + align:start position:0% +probability that the highest draws + + + align:start position:0% +probability that the highest draws +closest to feta increases that's right + + align:start position:0% +closest to feta increases that's right + + + align:start position:0% +closest to feta increases that's right +that's right so we're getting so this + + align:start position:0% +that's right so we're getting so this + + + align:start position:0% +that's right so we're getting so this +estimator is sort of getting close but + + align:start position:0% +estimator is sort of getting close but + + + align:start position:0% +estimator is sort of getting close but +it's but it's always going to be biased + + align:start position:0% +it's but it's always going to be biased + + + align:start position:0% +it's but it's always going to be biased +in for a finite sample + + align:start position:0% +in for a finite sample + + + align:start position:0% +in for a finite sample +because always that the nth order + + align:start position:0% +because always that the nth order + + + align:start position:0% +because always that the nth order +statistic is always less than or equal + + align:start position:0% +statistic is always less than or equal + + + align:start position:0% +statistic is always less than or equal +to Theta it's never greater than Theta + + align:start position:0% +to Theta it's never greater than Theta + + + align:start position:0% +to Theta it's never greater than Theta +it's always less than or equal to Theta + + align:start position:0% +it's always less than or equal to Theta + + + align:start position:0% +it's always less than or equal to Theta +and it's equal to Theta with zero + + align:start position:0% +and it's equal to Theta with zero + + + align:start position:0% +and it's equal to Theta with zero +probability okay so that's sort of the + + align:start position:0% +probability okay so that's sort of the + + + align:start position:0% +probability okay so that's sort of the +the way that you know that this is going + + align:start position:0% +the way that you know that this is going + + + align:start position:0% +the way that you know that this is going +to be a biased estimator the intuition I + + align:start position:0% +to be a biased estimator the intuition I + + + align:start position:0% +to be a biased estimator the intuition I +guess that I use okay so let's verify + + align:start position:0% +guess that I use okay so let's verify + + + align:start position:0% +guess that I use okay so let's verify +this okay we're not we can't just use + + align:start position:0% +this okay we're not we can't just use + + + align:start position:0% +this okay we're not we can't just use +the properties of uh expectation like we + + align:start position:0% +the properties of uh expectation like we + + + align:start position:0% +the properties of uh expectation like we +did on the last slide to calculate the + + align:start position:0% +did on the last slide to calculate the + + + align:start position:0% +did on the last slide to calculate the +uh the expectation of this estimator and + + align:start position:0% +uh the expectation of this estimator and + + + align:start position:0% +uh the expectation of this estimator and +so we're going to do it directly using + + align:start position:0% +so we're going to do it directly using + + + align:start position:0% +so we're going to do it directly using +the definition of + + align:start position:0% +the definition of + + + align:start position:0% +the definition of +expectation and in order to do that we + + align:start position:0% +expectation and in order to do that we + + + align:start position:0% +expectation and in order to do that we +first need the PDF of the inth order + + align:start position:0% +first need the PDF of the inth order + + + align:start position:0% +first need the PDF of the inth order +statistic well we've seen that before so + + align:start position:0% +statistic well we've seen that before so + + + align:start position:0% +statistic well we've seen that before so +we'll just go back to previous uh + + align:start position:0% +we'll just go back to previous uh + + + align:start position:0% +we'll just go back to previous uh +lecture and recall that this is the sort + + align:start position:0% +lecture and recall that this is the sort + + + align:start position:0% +lecture and recall that this is the sort +of General um that's the general formula + + align:start position:0% +of General um that's the general formula + + + align:start position:0% +of General um that's the general formula +for the PDF of the nth order statistic + + align:start position:0% +for the PDF of the nth order statistic + + + align:start position:0% +for the PDF of the nth order statistic +from some distribution F okay now we + + align:start position:0% +from some distribution F okay now we + + + align:start position:0% +from some distribution F okay now we +have a specific distribution here zero + + align:start position:0% +have a specific distribution here zero + + + align:start position:0% +have a specific distribution here zero +uniform uh sorry uniform zero Theta so + + align:start position:0% +uniform uh sorry uniform zero Theta so + + + align:start position:0% +uniform uh sorry uniform zero Theta so +we'll plug in that a specific uh PDF + + align:start position:0% +we'll plug in that a specific uh PDF + + + align:start position:0% +we'll plug in that a specific uh PDF +plug in the uniform PDF here and the + + align:start position:0% +plug in the uniform PDF here and the + + + align:start position:0% +plug in the uniform PDF here and the +uniform CDF here and then we get + + align:start position:0% +uniform CDF here and then we get + + + align:start position:0% +uniform CDF here and then we get +this + + align:start position:0% +this + + + align:start position:0% +this +okay and then it just simplifies to this + + align:start position:0% +okay and then it just simplifies to this + + + align:start position:0% +okay and then it just simplifies to this +okay so now we have the PDF of the nth + + align:start position:0% +okay so now we have the PDF of the nth + + + align:start position:0% +okay so now we have the PDF of the nth +order statistic we'll be able to + + align:start position:0% +order statistic we'll be able to + + + align:start position:0% +order statistic we'll be able to +calculate its expectation with + + align:start position:0% +calculate its expectation with + + + align:start position:0% +calculate its expectation with +that okay and so what we did is I just + + align:start position:0% +that okay and so what we did is I just + + + align:start position:0% +that okay and so what we did is I just +took the PDF from the previous slide and + + align:start position:0% +took the PDF from the previous slide and + + + align:start position:0% +took the PDF from the previous slide and +plugged it into the definition of + + align:start position:0% +plugged it into the definition of + + + align:start position:0% +plugged it into the definition of +expectation remember the expectation of + + align:start position:0% +expectation remember the expectation of + + + align:start position:0% +expectation remember the expectation of +a random variable is just equal to + + align:start position:0% +a random variable is just equal to + + + align:start position:0% +a random variable is just equal to +that's continuous it's just equal to the + + align:start position:0% +that's continuous it's just equal to the + + + align:start position:0% +that's continuous it's just equal to the +integral of x times the PDF so that's + + align:start position:0% +integral of x times the PDF so that's + + + align:start position:0% +integral of x times the PDF so that's +exactly what I did there I solved the + + align:start position:0% +exactly what I did there I solved the + + + align:start position:0% +exactly what I did there I solved the +integral and + + align:start position:0% +integral and + + + align:start position:0% +integral and +um you know just a couple of steps of + + align:start position:0% +um you know just a couple of steps of + + + align:start position:0% +um you know just a couple of steps of +math later I get that it's equal to n + + align:start position:0% +math later I get that it's equal to n + + + align:start position:0% +math later I get that it's equal to n +over n + 1 * + + align:start position:0% +over n + 1 * + + + align:start position:0% +over n + 1 * +Theta okay so not only is our intuition + + align:start position:0% +Theta okay so not only is our intuition + + + align:start position:0% +Theta okay so not only is our intuition +that um the bi that it's biased is + + align:start position:0% +that um the bi that it's biased is + + + align:start position:0% +that um the bi that it's biased is +confirmed here but also our intuition + + align:start position:0% +confirmed here but also our intuition + + + align:start position:0% +confirmed here but also our intuition +that the bias is going down as the + + align:start position:0% +that the bias is going down as the + + + align:start position:0% +that the bias is going down as the +sample size is getting bigger is also + + align:start position:0% +sample size is getting bigger is also + + + align:start position:0% +sample size is getting bigger is also +confirmed + + align:start position:0% +confirmed + + + align:start position:0% +confirmed +okay does this make + + align:start position:0% +okay does this make + + + align:start position:0% +okay does this make +sense okay so so having an unb estimator + + align:start position:0% +sense okay so so having an unb estimator + + + align:start position:0% +sense okay so so having an unb estimator +is great is that the only thing we care + + align:start position:0% +is great is that the only thing we care + + + align:start position:0% +is great is that the only thing we care +about I think you guess that the answer + + align:start position:0% +about I think you guess that the answer + + + align:start position:0% +about I think you guess that the answer +is probably no it's not the only thing + + align:start position:0% +is probably no it's not the only thing + + + align:start position:0% +is probably no it's not the only thing +we care about oh so yeah I guess this is + + align:start position:0% +we care about oh so yeah I guess this is + + + align:start position:0% +we care about oh so yeah I guess this is +what I already said not surprising the + + align:start position:0% +what I already said not surprising the + + + align:start position:0% +what I already said not surprising the +estimator always be less than or equal + + align:start position:0% +estimator always be less than or equal + + + align:start position:0% +estimator always be less than or equal +to Theta + + align:start position:0% +to Theta + + + align:start position:0% +to Theta +okay oh sorry before we get to the + + align:start position:0% +okay oh sorry before we get to the + + + align:start position:0% +okay oh sorry before we get to the +second Criterion I just want to give uh + + align:start position:0% +second Criterion I just want to give uh + + + align:start position:0% +second Criterion I just want to give uh +give you a couple of + + align:start position:0% +give you a couple of + + + align:start position:0% +give you a couple of +useful um + + align:start position:0% +useful um + + + align:start position:0% +useful um +results about sort of unbiased + + align:start position:0% +results about sort of unbiased + + + align:start position:0% +results about sort of unbiased +estimators so the first uh result is + + align:start position:0% +estimators so the first uh result is + + + align:start position:0% +estimators so the first uh result is +that if we have a sample mean for an IID + + align:start position:0% +that if we have a sample mean for an IID + + + align:start position:0% +that if we have a sample mean for an IID +sample then that sample mean is an + + align:start position:0% +sample then that sample mean is an + + + align:start position:0% +sample then that sample mean is an +unbiased estimator for the population + + align:start position:0% +unbiased estimator for the population + + + align:start position:0% +unbiased estimator for the population +mean okay the the mean of the underlying + + align:start position:0% +mean okay the the mean of the underlying + + + align:start position:0% +mean okay the the mean of the underlying +population okay so that's always going + + align:start position:0% +population okay so that's always going + + + align:start position:0% +population okay so that's always going +to be true the the uh you know for an + + align:start position:0% +to be true the the uh you know for an + + + align:start position:0% +to be true the the uh you know for an +IID sample the sample mean is unbiased + + align:start position:0% +IID sample the sample mean is unbiased + + + align:start position:0% +IID sample the sample mean is unbiased +for the population mean now we all we + + align:start position:0% +for the population mean now we all we + + + align:start position:0% +for the population mean now we all we +actually already knew this we didn't use + + align:start position:0% +actually already knew this we didn't use + + + align:start position:0% +actually already knew this we didn't use +the word unbiased but remember when we + + align:start position:0% +the word unbiased but remember when we + + + align:start position:0% +the word unbiased but remember when we +introduced samp LE mean we calculated + + align:start position:0% +introduced samp LE mean we calculated + + + align:start position:0% +introduced samp LE mean we calculated +the expectation of the sample mean you + + align:start position:0% +the expectation of the sample mean you + + + align:start position:0% +the expectation of the sample mean you +guys remember that calculation okay we + + align:start position:0% +guys remember that calculation okay we + + + align:start position:0% +guys remember that calculation okay we +calculated the expectation the sample + + align:start position:0% +calculated the expectation the sample + + + align:start position:0% +calculated the expectation the sample +mean and it was equal to Mu the the + + align:start position:0% +mean and it was equal to Mu the the + + + align:start position:0% +mean and it was equal to Mu the the +underlying mean or the population mean + + align:start position:0% +underlying mean or the population mean + + + align:start position:0% +underlying mean or the population mean +so in fact we already knew + + align:start position:0% +so in fact we already knew + + + align:start position:0% +so in fact we already knew +that another result that we haven't seen + + align:start position:0% +that another result that we haven't seen + + + align:start position:0% +that another result that we haven't seen +before because I haven't even defined uh + + align:start position:0% +before because I haven't even defined uh + + + align:start position:0% +before because I haven't even defined uh +what a sample variance is but it's a + + align:start position:0% +what a sample variance is but it's a + + + align:start position:0% +what a sample variance is but it's a +useful result nonetheless is that if we + + align:start position:0% +useful result nonetheless is that if we + + + align:start position:0% +useful result nonetheless is that if we +have an IID sample and we com compute + + align:start position:0% +have an IID sample and we com compute + + + align:start position:0% +have an IID sample and we com compute +this estimator here it's called the + + align:start position:0% +this estimator here it's called the + + + align:start position:0% +this estimator here it's called the +sample variance this is going to be + + align:start position:0% +sample variance this is going to be + + + align:start position:0% +sample variance this is going to be +unbiased for the population + + align:start position:0% +unbiased for the population + + + align:start position:0% +unbiased for the population +variance + + align:start position:0% +variance + + + align:start position:0% +variance +okay so I I am leaving out the proof of + + align:start position:0% +okay so I I am leaving out the proof of + + + align:start position:0% +okay so I I am leaving out the proof of +that it's a little it's kind of a little + + align:start position:0% +that it's a little it's kind of a little + + + align:start position:0% +that it's a little it's kind of a little +fussy a bit of a fussy proof and I don't + + align:start position:0% +fussy a bit of a fussy proof and I don't + + + align:start position:0% +fussy a bit of a fussy proof and I don't +think it's very instructive but if + + align:start position:0% +think it's very instructive but if + + + align:start position:0% +think it's very instructive but if +anyone's interested happy to show + + align:start position:0% + + + + align:start position:0% + +you yep before we move on I I wanted to + + align:start position:0% +you yep before we move on I I wanted to + + + align:start position:0% +you yep before we move on I I wanted to +ask a question about this the sample + + align:start position:0% +ask a question about this the sample + + + align:start position:0% +ask a question about this the sample +mean for an i sample is unbi population + + align:start position:0% +mean for an i sample is unbi population + + + align:start position:0% +mean for an i sample is unbi population +me um does the fact that it's unbiased + + align:start position:0% +me um does the fact that it's unbiased + + + align:start position:0% +me um does the fact that it's unbiased +mean that you're getting the actual + + align:start position:0% +mean that you're getting the actual + + + align:start position:0% +mean that you're getting the actual +population mean when you do the sample + + align:start position:0% +population mean when you do the sample + + + align:start position:0% +population mean when you do the sample +mean or no I don't think that's happen + + align:start position:0% +mean or no I don't think that's happen + + + align:start position:0% +mean or no I don't think that's happen +no so what it means is that the sample + + align:start position:0% +no so what it means is that the sample + + + align:start position:0% +no so what it means is that the sample +mean has a + + align:start position:0% +mean has a + + + align:start position:0% +mean has a +distribution and that distribution the + + align:start position:0% +distribution and that distribution the + + + align:start position:0% +distribution and that distribution the +expectation of that distribution is the + + align:start position:0% +expectation of that distribution is the + + + align:start position:0% +expectation of that distribution is the +population mean okay + + align:start position:0% +population mean okay + + + align:start position:0% +population mean okay +so here there's some distribution maybe + + align:start position:0% +so here there's some distribution maybe + + + align:start position:0% +so here there's some distribution maybe +it's uniform maybe it's + + align:start position:0% +it's uniform maybe it's + + + align:start position:0% +it's uniform maybe it's +normal whatever there's some + + align:start position:0% +normal whatever there's some + + + align:start position:0% +normal whatever there's some +distribution that governs that that that + + align:start position:0% +distribution that governs that that that + + + align:start position:0% +distribution that governs that that that +our random sample is governed by okay a + + align:start position:0% +our random sample is governed by okay a + + + align:start position:0% +our random sample is governed by okay a +random sample is drawn by or drawn from + + align:start position:0% +random sample is drawn by or drawn from + + + align:start position:0% +random sample is drawn by or drawn from +okay and then we get a random sample we + + align:start position:0% +okay and then we get a random sample we + + + align:start position:0% +okay and then we get a random sample we +compute the sample mean and the the + + align:start position:0% +compute the sample mean and the the + + + align:start position:0% +compute the sample mean and the the +distribution of the sample mean so if we + + align:start position:0% +distribution of the sample mean so if we + + + align:start position:0% +distribution of the sample mean so if we +think of the sample mean as a an + + align:start position:0% +think of the sample mean as a an + + + align:start position:0% +think of the sample mean as a an +estimator it's going to + + align:start position:0% + + + + align:start position:0% + +be it's it's going to have expect + + align:start position:0% +be it's it's going to have expect + + + align:start position:0% +be it's it's going to have expect +expectation sample mean any + + align:start position:0% +expectation sample mean any + + + align:start position:0% +expectation sample mean any +particular realization of that estimator + + align:start position:0% +particular realization of that estimator + + + align:start position:0% +particular realization of that estimator +so like if we have when we have the the + + align:start position:0% +so like if we have when we have the the + + + align:start position:0% +so like if we have when we have the the +numbers you know the realizations for + + align:start position:0% +numbers you know the realizations for + + + align:start position:0% +numbers you know the realizations for +the um random sample and we plug them in + + align:start position:0% +the um random sample and we plug them in + + + align:start position:0% +the um random sample and we plug them in +to the function for the estimator then + + align:start position:0% +to the function for the estimator then + + + align:start position:0% +to the function for the estimator then +basically what we're doing is we're + + align:start position:0% +basically what we're doing is we're + + + align:start position:0% +basically what we're doing is we're +getting some realization from this + + align:start position:0% +getting some realization from this + + + align:start position:0% +getting some realization from this +distribution so it's it depending on how + + align:start position:0% +distribution so it's it depending on how + + + align:start position:0% +distribution so it's it depending on how +tightly distributed it is around the the + + align:start position:0% +tightly distributed it is around the the + + + align:start position:0% +tightly distributed it is around the the +the population mean it could be you know + + align:start position:0% +the population mean it could be you know + + + align:start position:0% +the population mean it could be you know +it could very close to this with high + + align:start position:0% + + + + align:start position:0% + +probability + + align:start position:0% + + + + align:start position:0% + +okay okay questions about this so these + + align:start position:0% +okay okay questions about this so these + + + align:start position:0% +okay okay questions about this so these +are just two sort of useful facts that + + align:start position:0% +are just two sort of useful facts that + + + align:start position:0% +are just two sort of useful facts that +we'll refer to uh in the + + align:start position:0% + + + + align:start position:0% + +future okay so now uh is unbiasedness + + align:start position:0% +future okay so now uh is unbiasedness + + + align:start position:0% +future okay so now uh is unbiasedness +all we care about in an estimator okay + + align:start position:0% +all we care about in an estimator okay + + + align:start position:0% +all we care about in an estimator okay +the answer is no so uh in particular + + align:start position:0% +the answer is no so uh in particular + + + align:start position:0% +the answer is no so uh in particular +there are other aspects of distributions + + align:start position:0% +there are other aspects of distributions + + + align:start position:0% +there are other aspects of distributions +of the estimators that we might care + + align:start position:0% +of the estimators that we might care + + + align:start position:0% +of the estimators that we might care +about we might care about I just alluded + + align:start position:0% +about we might care about I just alluded + + + align:start position:0% +about we might care about I just alluded +to this how tightly distributed it is + + align:start position:0% +to this how tightly distributed it is + + + align:start position:0% +to this how tightly distributed it is +around the unknown parameter okay we + + align:start position:0% +around the unknown parameter okay we + + + align:start position:0% +around the unknown parameter okay we +could have an estimator that has a very + + align:start position:0% +could have an estimator that has a very + + + align:start position:0% +could have an estimator that has a very +diffuse distribution and that estimator + + align:start position:0% +diffuse distribution and that estimator + + + align:start position:0% +diffuse distribution and that estimator +even if its expectation is is the the um + + align:start position:0% +even if its expectation is is the the um + + + align:start position:0% +even if its expectation is is the the um +parameter that we're trying to estimate + + align:start position:0% +parameter that we're trying to estimate + + + align:start position:0% +parameter that we're trying to estimate +even if that's its expectation in other + + align:start position:0% +even if that's its expectation in other + + + align:start position:0% +even if that's its expectation in other +words even if it's unbiased might not be + + align:start position:0% +words even if it's unbiased might not be + + + align:start position:0% +words even if it's unbiased might not be +very useful to us if it has lots of + + align:start position:0% +very useful to us if it has lots of + + + align:start position:0% +very useful to us if it has lots of +probability far away from the real print + + align:start position:0% +probability far away from the real print + + + align:start position:0% +probability far away from the real print +okay and that's what efficiency is about + + align:start position:0% +okay and that's what efficiency is about + + + align:start position:0% +okay and that's what efficiency is about +so given two unbiased estimators Theta 1 + + align:start position:0% +so given two unbiased estimators Theta 1 + + + align:start position:0% +so given two unbiased estimators Theta 1 +hat and Theta 2 hat Theta 1 Hat is more + + align:start position:0% +hat and Theta 2 hat Theta 1 Hat is more + + + align:start position:0% +hat and Theta 2 hat Theta 1 Hat is more +efficient than Theta 2 hat if for a + + align:start position:0% +efficient than Theta 2 hat if for a + + + align:start position:0% +efficient than Theta 2 hat if for a +given sample size the variance of theta + + align:start position:0% +given sample size the variance of theta + + + align:start position:0% +given sample size the variance of theta +1 Hat is less than the variance of theta + + align:start position:0% +1 Hat is less than the variance of theta + + + align:start position:0% +1 Hat is less than the variance of theta +2 hat okay so let me show you a + + align:start position:0% +2 hat okay so let me show you a + + + align:start position:0% +2 hat okay so let me show you a +picture so here we have two unbiased + + align:start position:0% +picture so here we have two unbiased + + + align:start position:0% +picture so here we have two unbiased +estimators we have an efficient one + + align:start position:0% +estimators we have an efficient one + + + align:start position:0% +estimators we have an efficient one +whose distribution is pretty tightly + + align:start position:0% +whose distribution is pretty tightly + + + align:start position:0% +whose distribution is pretty tightly +distributed or concentrated around the + + align:start position:0% +distributed or concentrated around the + + + align:start position:0% +distributed or concentrated around the +unknown parameter and we have an + + align:start position:0% +unknown parameter and we have an + + + align:start position:0% +unknown parameter and we have an +inefficient one whose distribution is + + align:start position:0% +inefficient one whose distribution is + + + align:start position:0% +inefficient one whose distribution is +much more spread out and we're going to + + align:start position:0% +much more spread out and we're going to + + + align:start position:0% +much more spread out and we're going to +we're going to prefer the efficient + + align:start position:0% +we're going to prefer the efficient + + + align:start position:0% +we're going to prefer the efficient +estimator + + align:start position:0% +estimator + + + align:start position:0% +estimator +okay is that clear to everyone why we + + align:start position:0% +okay is that clear to everyone why we + + + align:start position:0% +okay is that clear to everyone why we +prefer + + align:start position:0% +prefer + + + align:start position:0% +prefer +okay okay so note that this definition + + align:start position:0% +okay okay so note that this definition + + + align:start position:0% +okay okay so note that this definition +has defined efficiency here just for + + align:start position:0% +has defined efficiency here just for + + + align:start position:0% +has defined efficiency here just for +unbiased estimators the notion of + + align:start position:0% +unbiased estimators the notion of + + + align:start position:0% +unbiased estimators the notion of +efficiency is broader than that so it + + align:start position:0% +efficiency is broader than that so it + + + align:start position:0% +efficiency is broader than that so it +can exist for sort of broader classes of + + align:start position:0% +can exist for sort of broader classes of + + + align:start position:0% +can exist for sort of broader classes of +estimators as well I'm not going to give + + align:start position:0% +estimators as well I'm not going to give + + + align:start position:0% +estimators as well I'm not going to give +you a formal definition but just think + + align:start position:0% +you a formal definition but just think + + + align:start position:0% +you a formal definition but just think +that if an estimator has a larger + + align:start position:0% +that if an estimator has a larger + + + align:start position:0% +that if an estimator has a larger +variance it's less efficient than an + + align:start position:0% +variance it's less efficient than an + + + align:start position:0% +variance it's less efficient than an +estimator with a smaller variance okay + + align:start position:0% +estimator with a smaller variance okay + + + align:start position:0% +estimator with a smaller variance okay +and we typically Define that in CL in + + align:start position:0% +and we typically Define that in CL in + + + align:start position:0% +and we typically Define that in CL in +different classes of + + align:start position:0% + + + + align:start position:0% + +estimators + + align:start position:0% +estimators + + + align:start position:0% +estimators +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so fine suppose we have an efficient + + align:start position:0% +so fine suppose we have an efficient + + + align:start position:0% +so fine suppose we have an efficient +estimator and uh or you know an + + align:start position:0% +estimator and uh or you know an + + + align:start position:0% +estimator and uh or you know an +estimator has a small variance and then + + align:start position:0% +estimator has a small variance and then + + + align:start position:0% +estimator has a small variance and then +we have another estimator it has a + + align:start position:0% +we have another estimator it has a + + + align:start position:0% +we have another estimator it has a +larger variance uh but it's unbiased + + align:start position:0% +larger variance uh but it's unbiased + + + align:start position:0% +larger variance uh but it's unbiased +okay so sorry the first one is biased + + align:start position:0% +okay so sorry the first one is biased + + + align:start position:0% +okay so sorry the first one is biased +has a small variance the second one is + + align:start position:0% +has a small variance the second one is + + + align:start position:0% +has a small variance the second one is +unbiased and has a large variance how do + + align:start position:0% +unbiased and has a large variance how do + + + align:start position:0% +unbiased and has a large variance how do +we know which one to choose well there's + + align:start position:0% +we know which one to choose well there's + + + align:start position:0% +we know which one to choose well there's +no right answer okay so there's no + + align:start position:0% +no right answer okay so there's no + + + align:start position:0% +no right answer okay so there's no +there's no I'm you know I can't sort of + + align:start position:0% +there's no I'm you know I can't sort of + + + align:start position:0% +there's no I'm you know I can't sort of +tell you the theorem that says well you + + align:start position:0% +tell you the theorem that says well you + + + align:start position:0% +tell you the theorem that says well you +always need to choose this estimator + + align:start position:0% +always need to choose this estimator + + + align:start position:0% +always need to choose this estimator +over over the other one uh but there + + align:start position:0% +over over the other one uh but there + + + align:start position:0% +over over the other one uh but there +might be uh there might be sort of um + + align:start position:0% +might be uh there might be sort of um + + + align:start position:0% +might be uh there might be sort of um +other aside from just kind of picking + + align:start position:0% +other aside from just kind of picking + + + align:start position:0% +other aside from just kind of picking +your favorite estimator there might be + + align:start position:0% +your favorite estimator there might be + + + align:start position:0% +your favorite estimator there might be +kind of a more uh routinized way to + + align:start position:0% +kind of a more uh routinized way to + + + align:start position:0% +kind of a more uh routinized way to +trade off bias and efficiency in + + align:start position:0% +trade off bias and efficiency in + + + align:start position:0% +trade off bias and efficiency in +estimation and one way to do this is um + + align:start position:0% +estimation and one way to do this is um + + + align:start position:0% +estimation and one way to do this is um +minimum or is u mean square error okay + + align:start position:0% +minimum or is u mean square error okay + + + align:start position:0% +minimum or is u mean square error okay +so + + align:start position:0% +so + + + align:start position:0% +so +um I'm going to Define mean square error + + align:start position:0% +um I'm going to Define mean square error + + + align:start position:0% +um I'm going to Define mean square error +as the expectation of theta hat minus + + align:start position:0% +as the expectation of theta hat minus + + + align:start position:0% +as the expectation of theta hat minus +Theta Square squar okay and that can be + + align:start position:0% +Theta Square squar okay and that can be + + + align:start position:0% +Theta Square squar okay and that can be +Rewritten as the variance of theta hat + + align:start position:0% +Rewritten as the variance of theta hat + + + align:start position:0% +Rewritten as the variance of theta hat +so we can think of that basically is the + + align:start position:0% +so we can think of that basically is the + + + align:start position:0% +so we can think of that basically is the +efficiency a measure of the efficiency + + align:start position:0% +efficiency a measure of the efficiency + + + align:start position:0% +efficiency a measure of the efficiency +of the estimator plus the expectation of + + align:start position:0% +of the estimator plus the expectation of + + + align:start position:0% +of the estimator plus the expectation of +theta hat minus Theta quantity squared + + align:start position:0% +theta hat minus Theta quantity squared + + + align:start position:0% +theta hat minus Theta quantity squared +and that is uh in fact the bias that is + + align:start position:0% +and that is uh in fact the bias that is + + + align:start position:0% +and that is uh in fact the bias that is +you know sort of this difference here is + + align:start position:0% +you know sort of this difference here is + + + align:start position:0% +you know sort of this difference here is +defined as the bias so the so that last + + align:start position:0% +defined as the bias so the so that last + + + align:start position:0% +defined as the bias so the so that last +term is the bias squared okay okay so + + align:start position:0% +term is the bias squared okay okay so + + + align:start position:0% +term is the bias squared okay okay so +for unbiased estimators that quantity is + + align:start position:0% +for unbiased estimators that quantity is + + + align:start position:0% +for unbiased estimators that quantity is +going to be zero for biased estimators + + align:start position:0% +going to be zero for biased estimators + + + align:start position:0% +going to be zero for biased estimators +it's going to be positive okay so mean + + align:start position:0% +it's going to be positive okay so mean + + + align:start position:0% +it's going to be positive okay so mean +square error is a way to to uh you know + + align:start position:0% +square error is a way to to uh you know + + + align:start position:0% +square error is a way to to uh you know +sort of trade off bias and efficiency + + align:start position:0% +sort of trade off bias and efficiency + + + align:start position:0% +sort of trade off bias and efficiency +you can choose a estimator that is the + + align:start position:0% +you can choose a estimator that is the + + + align:start position:0% +you can choose a estimator that is the +minimum mean squared error estimator and + + align:start position:0% +minimum mean squared error estimator and + + + align:start position:0% +minimum mean squared error estimator and +then that sort of allows you know + + align:start position:0% +then that sort of allows you know + + + align:start position:0% +then that sort of allows you know +basically allows this explicit trade-off + + align:start position:0% +basically allows this explicit trade-off + + + align:start position:0% +basically allows this explicit trade-off +between bias and + + align:start position:0% +between bias and + + + align:start position:0% +between bias and +efficiency okay + + align:start position:0% +efficiency okay + + + align:start position:0% +efficiency okay +um so I should point out it is a + + align:start position:0% +um so I should point out it is a + + + align:start position:0% +um so I should point out it is a +reasonable way to trade off bias and + + align:start position:0% +reasonable way to trade off bias and + + + align:start position:0% +reasonable way to trade off bias and +efficiency it's not the only one and + + align:start position:0% +efficiency it's not the only one and + + + align:start position:0% +efficiency it's not the only one and +like I said it's not you know there's no + + align:start position:0% +like I said it's not you know there's no + + + align:start position:0% +like I said it's not you know there's no +right answer when it comes to choosing + + align:start position:0% +right answer when it comes to choosing + + + align:start position:0% +right answer when it comes to choosing +among estimators uh that you know that + + align:start position:0% +among estimators uh that you know that + + + align:start position:0% +among estimators uh that you know that +have sort of that are not dominated in + + align:start position:0% +have sort of that are not dominated in + + + align:start position:0% +have sort of that are not dominated in +in all + + align:start position:0% + + + + align:start position:0% + +ways okay and I'll finally mention uh + + align:start position:0% +ways okay and I'll finally mention uh + + + align:start position:0% +ways okay and I'll finally mention uh +one additional + + align:start position:0% +one additional + + + align:start position:0% +one additional +Criterion um Thea uh sorry Theta hat is + + align:start position:0% +Criterion um Thea uh sorry Theta hat is + + + align:start position:0% +Criterion um Thea uh sorry Theta hat is +a consistent estimator for Theta if the + + align:start position:0% +a consistent estimator for Theta if the + + + align:start position:0% +a consistent estimator for Theta if the +following is true you take the absolute + + align:start position:0% +following is true you take the absolute + + + align:start position:0% +following is true you take the absolute +value the absolute difference between uh + + align:start position:0% +value the absolute difference between uh + + + align:start position:0% +value the absolute difference between uh +Theta and Theta + + align:start position:0% +Theta and Theta + + + align:start position:0% +Theta and Theta +hat and the probability of that absolute + + align:start position:0% +hat and the probability of that absolute + + + align:start position:0% +hat and the probability of that absolute +difference being less than some uh small + + align:start position:0% +difference being less than some uh small + + + align:start position:0% +difference being less than some uh small +uh number Delta goes to one as n goes to + + align:start position:0% +uh number Delta goes to one as n goes to + + + align:start position:0% +uh number Delta goes to one as n goes to +Infinity okay so practically speak + + align:start position:0% +Infinity okay so practically speak + + + align:start position:0% +Infinity okay so practically speak +speaking what does this mean well first + + align:start position:0% +speaking what does this mean well first + + + align:start position:0% +speaking what does this mean well first +of all let me draw you a + + align:start position:0% +of all let me draw you a + + + align:start position:0% +of all let me draw you a +picture okay so uh this is what a + + align:start position:0% +picture okay so uh this is what a + + + align:start position:0% +picture okay so uh this is what a +consistent estimator looks like as n + + align:start position:0% +consistent estimator looks like as n + + + align:start position:0% +consistent estimator looks like as n +goes to Infinity so basically you have a + + align:start position:0% +goes to Infinity so basically you have a + + + align:start position:0% +goes to Infinity so basically you have a +consistent estimator I've drawn this one + + align:start position:0% +consistent estimator I've drawn this one + + + align:start position:0% +consistent estimator I've drawn this one +to be unbiased for all in it doesn't + + align:start position:0% +to be unbiased for all in it doesn't + + + align:start position:0% +to be unbiased for all in it doesn't +have to be unbiased but that that's just + + align:start position:0% +have to be unbiased but that that's just + + + align:start position:0% +have to be unbiased but that that's just +the way I drew the picture here so + + align:start position:0% +the way I drew the picture here so + + + align:start position:0% +the way I drew the picture here so +basically you have an estimator and it + + align:start position:0% +basically you have an estimator and it + + + align:start position:0% +basically you have an estimator and it +has a distribution and as n uh goes to + + align:start position:0% +has a distribution and as n uh goes to + + + align:start position:0% +has a distribution and as n uh goes to +Infinity the distribution is getting + + align:start position:0% +Infinity the distribution is getting + + + align:start position:0% +Infinity the distribution is getting +more and more concentrated ated around + + align:start position:0% +more and more concentrated ated around + + + align:start position:0% +more and more concentrated ated around +the true parameter and in fact in the + + align:start position:0% +the true parameter and in fact in the + + + align:start position:0% +the true parameter and in fact in the +limit um it collapses to a single point + + align:start position:0% +limit um it collapses to a single point + + + align:start position:0% +limit um it collapses to a single point +at the true parameter as n goes to + + align:start position:0% +at the true parameter as n goes to + + + align:start position:0% +at the true parameter as n goes to +Infinity okay so this is what um what's + + align:start position:0% +Infinity okay so this is what um what's + + + align:start position:0% +Infinity okay so this is what um what's +known as a consistent + + align:start position:0% +known as a consistent + + + align:start position:0% +known as a consistent +estimator so let me just emphasize I've + + align:start position:0% +estimator so let me just emphasize I've + + + align:start position:0% +estimator so let me just emphasize I've +drawn this picture um you know for an + + align:start position:0% +drawn this picture um you know for an + + + align:start position:0% +drawn this picture um you know for an +estimator that's unbiased a consistent + + align:start position:0% +estimator that's unbiased a consistent + + + align:start position:0% +estimator that's unbiased a consistent +estimator doesn't have to be unbiased I + + align:start position:0% +estimator doesn't have to be unbiased I + + + align:start position:0% +estimator doesn't have to be unbiased I +could have drawn you know all of these + + align:start position:0% +could have drawn you know all of these + + + align:start position:0% +could have drawn you know all of these +distributions having bias but the bias + + align:start position:0% +distributions having bias but the bias + + + align:start position:0% +distributions having bias but the bias +is going to zero + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +okay so I have in the interest of time I + + align:start position:0% +okay so I have in the interest of time I + + + align:start position:0% +okay so I have in the interest of time I +I haven't uh included these examples on + + align:start position:0% +I haven't uh included these examples on + + + align:start position:0% +I haven't uh included these examples on +um you know in the lecture notes but I + + align:start position:0% +um you know in the lecture notes but I + + + align:start position:0% +um you know in the lecture notes but I +will tell you in case you're curious + + align:start position:0% +will tell you in case you're curious + + + align:start position:0% +will tell you in case you're curious +that the two estimators that we looked + + align:start position:0% +that the two estimators that we looked + + + align:start position:0% +that the two estimators that we looked +at for the uniform zero Theta um uh + + align:start position:0% +at for the uniform zero Theta um uh + + + align:start position:0% +at for the uniform zero Theta um uh +random sample uh the unbiased estimator + + align:start position:0% +random sample uh the unbiased estimator + + + align:start position:0% +random sample uh the unbiased estimator +the one that was two times the sample + + align:start position:0% +the one that was two times the sample + + + align:start position:0% +the one that was two times the sample +mean uh was much less efficient than the + + align:start position:0% +mean uh was much less efficient than the + + + align:start position:0% +mean uh was much less efficient than the +biased estimator the one that the the + + align:start position:0% +biased estimator the one that the the + + + align:start position:0% +biased estimator the one that the the +nth order statistic okay and so in that + + align:start position:0% +nth order statistic okay and so in that + + + align:start position:0% +nth order statistic okay and so in that +in in that case you might want to choose + + align:start position:0% +in in that case you might want to choose + + + align:start position:0% +in in that case you might want to choose +the inth order statistic just because + + align:start position:0% +the inth order statistic just because + + + align:start position:0% +the inth order statistic just because +it's you know for um you know reasonably + + align:start position:0% +it's you know for um you know reasonably + + + align:start position:0% +it's you know for um you know reasonably +sized random sample uh it's just its + + align:start position:0% +sized random sample uh it's just its + + + align:start position:0% +sized random sample uh it's just its +distribution is going to be much more + + align:start position:0% +distribution is going to be much more + + + align:start position:0% +distribution is going to be much more +tightly distributed around uh you know + + align:start position:0% +tightly distributed around uh you know + + + align:start position:0% +tightly distributed around uh you know +near Theta than two times the random s + + align:start position:0% +near Theta than two times the random s + + + align:start position:0% +near Theta than two times the random s +or two times the sample + + align:start position:0% +or two times the sample + + + align:start position:0% +or two times the sample +mean + + align:start position:0% + + + + align:start position:0% + +okay okay so the criteria that I've gone + + align:start position:0% +okay okay so the criteria that I've gone + + + align:start position:0% +okay okay so the criteria that I've gone +through these they're probably the most + + align:start position:0% +through these they're probably the most + + + align:start position:0% +through these they're probably the most +important reasons for choosing one + + align:start position:0% +important reasons for choosing one + + + align:start position:0% +important reasons for choosing one +estimator over another um but they're + + align:start position:0% +estimator over another um but they're + + + align:start position:0% +estimator over another um but they're +they don't necessarily have to be the + + align:start position:0% +they don't necessarily have to be the + + + align:start position:0% +they don't necessarily have to be the +only considerations so sometimes + + align:start position:0% +only considerations so sometimes + + + align:start position:0% +only considerations so sometimes +estimators can be really difficult ult + + align:start position:0% +estimators can be really difficult ult + + + align:start position:0% +estimators can be really difficult ult +to compute like they can be uh used you + + align:start position:0% +to compute like they can be uh used you + + + align:start position:0% +to compute like they can be uh used you +know sort of hours of computer time or + + align:start position:0% +know sort of hours of computer time or + + + align:start position:0% +know sort of hours of computer time or +something like that and so you might + + align:start position:0% +something like that and so you might + + + align:start position:0% +something like that and so you might +choose an estimator just based on sort + + align:start position:0% +choose an estimator just based on sort + + + align:start position:0% +choose an estimator just based on sort +of + + align:start position:0% +of + + + align:start position:0% +of +computational Simplicity um and that's + + align:start position:0% +computational Simplicity um and that's + + + align:start position:0% +computational Simplicity um and that's +not an unreasonable thing to do you + + align:start position:0% +not an unreasonable thing to do you + + + align:start position:0% +not an unreasonable thing to do you +might also choose an estimator based on + + align:start position:0% +might also choose an estimator based on + + + align:start position:0% +might also choose an estimator based on +how robust it is what do I mean by + + align:start position:0% +how robust it is what do I mean by + + + align:start position:0% +how robust it is what do I mean by +robust well basically an estimator is + + align:start position:0% +robust well basically an estimator is + + + align:start position:0% +robust well basically an estimator is +robust if it still will do a decent job + + align:start position:0% +robust if it still will do a decent job + + + align:start position:0% +robust if it still will do a decent job +perform well for for estimating the + + align:start position:0% +perform well for for estimating the + + + align:start position:0% +perform well for for estimating the +unknown parameter even if some of your + + align:start position:0% +unknown parameter even if some of your + + + align:start position:0% +unknown parameter even if some of your +assumptions underlying assumptions are + + align:start position:0% +assumptions underlying assumptions are + + + align:start position:0% +assumptions underlying assumptions are +incorrect so for instance let's suppose + + align:start position:0% +incorrect so for instance let's suppose + + + align:start position:0% +incorrect so for instance let's suppose +that we um let's + + align:start position:0% + + + + align:start position:0% + +suppose that we want to estimate + + align:start position:0% +suppose that we want to estimate + + + align:start position:0% +suppose that we want to estimate +mu and we think + + align:start position:0% +mu and we think + + + align:start position:0% +mu and we think +that the random sample is drawn from a + + align:start position:0% +that the random sample is drawn from a + + + align:start position:0% +that the random sample is drawn from a +distribution that looks like this okay + + align:start position:0% +distribution that looks like this okay + + + align:start position:0% +distribution that looks like this okay +but in fact it's drawn from a + + align:start position:0% +but in fact it's drawn from a + + + align:start position:0% +but in fact it's drawn from a +distribution that looks like this + + align:start position:0% + + + + align:start position:0% + +so it's this is still the mean mu is + + align:start position:0% +so it's this is still the mean mu is + + + align:start position:0% +so it's this is still the mean mu is +still the mean of this distribution but + + align:start position:0% +still the mean of this distribution but + + + align:start position:0% +still the mean of this distribution but +uh We've assumed that um you know we're + + align:start position:0% +uh We've assumed that um you know we're + + + align:start position:0% +uh We've assumed that um you know we're +drawing from this distribution when in + + align:start position:0% +drawing from this distribution when in + + + align:start position:0% +drawing from this distribution when in +Factor we're drawing from that one a + + align:start position:0% +Factor we're drawing from that one a + + + align:start position:0% +Factor we're drawing from that one a +robust estimator will still do a good + + align:start position:0% +robust estimator will still do a good + + + align:start position:0% +robust estimator will still do a good +job of estimating me even if our + + align:start position:0% +job of estimating me even if our + + + align:start position:0% +job of estimating me even if our +assumptions about the underlying + + align:start position:0% +assumptions about the underlying + + + align:start position:0% +assumptions about the underlying +distribution are wrong okay and so uh + + align:start position:0% +distribution are wrong okay and so uh + + + align:start position:0% +distribution are wrong okay and so uh +sometimes we choose estimators that are + + align:start position:0% +sometimes we choose estimators that are + + + align:start position:0% +sometimes we choose estimators that are +robust to uh different assumptions if we + + align:start position:0% +robust to uh different assumptions if we + + + align:start position:0% +robust to uh different assumptions if we +don't have a good you know if we don't + + align:start position:0% +don't have a good you know if we don't + + + align:start position:0% +don't have a good you know if we don't +have a lot of confidence about our + + align:start position:0% +have a lot of confidence about our + + + align:start position:0% +have a lot of confidence about our +underlying + + align:start position:0% +underlying + + + align:start position:0% +underlying +assumptions + + align:start position:0% +assumptions + + + align:start position:0% +assumptions +okay oh and um yeah so I guess this is + + align:start position:0% +okay oh and um yeah so I guess this is + + + align:start position:0% +okay oh and um yeah so I guess this is +an example of a robust estimator that we + + align:start position:0% +an example of a robust estimator that we + + + align:start position:0% +an example of a robust estimator that we +talked about last time briefly it turns + + align:start position:0% +talked about last time briefly it turns + + + align:start position:0% +talked about last time briefly it turns +out that the two times the sample median + + align:start position:0% +out that the two times the sample median + + + align:start position:0% +out that the two times the sample median +estimator from the uniform example um + + align:start position:0% +estimator from the uniform example um + + + align:start position:0% +estimator from the uniform example um +has will have less bias than the two + + align:start position:0% +has will have less bias than the two + + + align:start position:0% +has will have less bias than the two +times the sample mean estimator uh if + + align:start position:0% +times the sample mean estimator uh if + + + align:start position:0% +times the sample mean estimator uh if +we've misspecified the tail + + align:start position:0% +we've misspecified the tail + + + align:start position:0% +we've misspecified the tail +probabilities in that uniform + + align:start position:0% +probabilities in that uniform + + + align:start position:0% +probabilities in that uniform +example okay so that's an example of a + + align:start position:0% +example okay so that's an example of a + + + align:start position:0% +example okay so that's an example of a +an estimator that um you know might be + + align:start position:0% +an estimator that um you know might be + + + align:start position:0% +an estimator that um you know might be +might actually not be as good as the + + align:start position:0% +might actually not be as good as the + + + align:start position:0% +might actually not be as good as the +other two estimators we saw in terms of + + align:start position:0% +other two estimators we saw in terms of + + + align:start position:0% +other two estimators we saw in terms of +bias and efficiency but might have this + + align:start position:0% +bias and efficiency but might have this + + + align:start position:0% +bias and efficiency but might have this +other property of robustness that could + + align:start position:0% +other property of robustness that could + + + align:start position:0% +other property of robustness that could +come in handy at some + + align:start position:0% +come in handy at some + + + align:start position:0% +come in handy at some +point yes those tail probabilities be + + align:start position:0% +point yes those tail probabilities be + + + align:start position:0% +point yes those tail probabilities be +be like underestimated or overestimated + + align:start position:0% +be like underestimated or overestimated + + + align:start position:0% +be like underestimated or overestimated +for that to POS or does it not matter + + align:start position:0% +for that to POS or does it not matter + + + align:start position:0% +for that to POS or does it not matter +well robust so robustness is basically + + align:start position:0% +well robust so robustness is basically + + + align:start position:0% +well robust so robustness is basically +just a a um it's just a um kind of a + + align:start position:0% +just a a um it's just a um kind of a + + + align:start position:0% +just a a um it's just a um kind of a +property of an estimator that says it's + + align:start position:0% +property of an estimator that says it's + + + align:start position:0% +property of an estimator that says it's +still performs well if your assumptions + + align:start position:0% +still performs well if your assumptions + + + align:start position:0% +still performs well if your assumptions +are incorrect and and it and it could be + + align:start position:0% +are incorrect and and it and it could be + + + align:start position:0% +are incorrect and and it and it could be +it could be that the estimator could + + align:start position:0% +it could be that the estimator could + + + align:start position:0% +it could be that the estimator could +only uh is only robust to miss + + align:start position:0% +only uh is only robust to miss + + + align:start position:0% +only uh is only robust to miss +specifications in One Direction and not + + align:start position:0% +specifications in One Direction and not + + + align:start position:0% +specifications in One Direction and not +the other direction that's possible but + + align:start position:0% +the other direction that's possible but + + + align:start position:0% +the other direction that's possible but +you know just the the sort of general + + align:start position:0% +you know just the the sort of general + + + align:start position:0% +you know just the the sort of general +definition of robust is just that that + + align:start position:0% +definition of robust is just that that + + + align:start position:0% +definition of robust is just that that +it's um not sensitive to the second part + + align:start position:0% +it's um not sensitive to the second part + + + align:start position:0% +it's um not sensitive to the second part +of this of the slide is it's showing + + align:start position:0% +of this of the slide is it's showing + + + align:start position:0% +of this of the slide is it's showing +that that's just an example of what + + align:start position:0% +that that's just an example of what + + + align:start position:0% +that that's just an example of what +could happen yeah it's not necessarily + + align:start position:0% +could happen yeah it's not necessarily + + + align:start position:0% +could happen yeah it's not necessarily +always true exactly that's right yep yes + + align:start position:0% +always true exactly that's right yep yes + + + align:start position:0% +always true exactly that's right yep yes +in that example what would be the + + align:start position:0% +in that example what would be the + + + align:start position:0% +in that example what would be the +um the wrong distribution that wee we + + align:start position:0% +um the wrong distribution that wee we + + + align:start position:0% +um the wrong distribution that wee we +so let's suppose so the we came up with + + align:start position:0% +so let's suppose so the we came up with + + + align:start position:0% +so let's suppose so the we came up with +this two times the sample median + + align:start position:0% +this two times the sample median + + + align:start position:0% +this two times the sample median +estimator in the uniform 0 to Theta + + align:start position:0% +estimator in the uniform 0 to Theta + + + align:start position:0% +estimator in the uniform 0 to Theta +example so let's suppose instead of + + align:start position:0% +example so let's suppose instead of + + + align:start position:0% +example so let's suppose instead of +uniform 0 to Theta let's + + align:start position:0% +uniform 0 to Theta let's + + + align:start position:0% +uniform 0 to Theta let's +suppose the um the distribution + + align:start position:0% + + + + align:start position:0% + +was look like that + + align:start position:0% +was look like that + + + align:start position:0% +was look like that +instead then um and and we carried + + align:start position:0% +instead then um and and we carried + + + align:start position:0% +instead then um and and we carried +through all of the analysis of the + + align:start position:0% +through all of the analysis of the + + + align:start position:0% +through all of the analysis of the +estimator as if this were the + + align:start position:0% +estimator as if this were the + + + align:start position:0% +estimator as if this were the +distribution then if we use the two + + align:start position:0% +distribution then if we use the two + + + align:start position:0% +distribution then if we use the two +times the sample median estimator we're + + align:start position:0% +times the sample median estimator we're + + + align:start position:0% +times the sample median estimator we're +probably uh going to do a better job + + align:start position:0% +probably uh going to do a better job + + + align:start position:0% +probably uh going to do a better job +estimating I I would have to sort of + + align:start position:0% +estimating I I would have to sort of + + + align:start position:0% +estimating I I would have to sort of +work it out to be sure but um in that + + align:start position:0% +work it out to be sure but um in that + + + align:start position:0% +work it out to be sure but um in that +example we're almost certainly going to + + align:start position:0% +example we're almost certainly going to + + + align:start position:0% +example we're almost certainly going to +do a better job of estimating Theta with + + align:start position:0% +do a better job of estimating Theta with + + + align:start position:0% +do a better job of estimating Theta with +the two times the median estimator than + + align:start position:0% +the two times the median estimator than + + + align:start position:0% +the two times the median estimator than +the two times the sample mean + + align:start position:0% +the two times the sample mean + + + align:start position:0% +the two times the sample mean +estimator + + align:start position:0% +estimator + + + align:start position:0% +estimator +yep + + align:start position:0% + + + + align:start position:0% + +okay okay so now we know at least + + align:start position:0% +okay okay so now we know at least + + + align:start position:0% +okay okay so now we know at least +roughly speaking how to figure out if an + + align:start position:0% +roughly speaking how to figure out if an + + + align:start position:0% +roughly speaking how to figure out if an +estimator is good once we have one okay + + align:start position:0% +estimator is good once we have one okay + + + align:start position:0% +estimator is good once we have one okay +so we have lots of different criteria to + + align:start position:0% +so we have lots of different criteria to + + + align:start position:0% +so we have lots of different criteria to +consider um and you know some some good + + align:start position:0% +consider um and you know some some good + + + align:start position:0% +consider um and you know some some good +guidelines but how do we get an + + align:start position:0% +guidelines but how do we get an + + + align:start position:0% +guidelines but how do we get an +estimator in the first place okay so the + + align:start position:0% +estimator in the first place okay so the + + + align:start position:0% +estimator in the first place okay so the +example that I went over in class A + + align:start position:0% +example that I went over in class A + + + align:start position:0% +example that I went over in class A +couple lectures ago + + align:start position:0% +couple lectures ago + + + align:start position:0% +couple lectures ago +uh we just kind of dreamed dreamed them + + align:start position:0% +uh we just kind of dreamed dreamed them + + + align:start position:0% +uh we just kind of dreamed dreamed them +up off the top of our head right which + + align:start position:0% +up off the top of our head right which + + + align:start position:0% +up off the top of our head right which +you know is is it turns out can + + align:start position:0% +you know is is it turns out can + + + align:start position:0% +you know is is it turns out can +sometimes result in in quite reasonable + + align:start position:0% +sometimes result in in quite reasonable + + + align:start position:0% +sometimes result in in quite reasonable +estimators but it might be a little + + align:start position:0% +estimators but it might be a little + + + align:start position:0% +estimators but it might be a little +comforting to know that you don't always + + align:start position:0% +comforting to know that you don't always + + + align:start position:0% +comforting to know that you don't always +just have to be able to dream things up + + align:start position:0% +just have to be able to dream things up + + + align:start position:0% +just have to be able to dream things up +off the top of your head okay so there + + align:start position:0% +off the top of your head okay so there + + + align:start position:0% +off the top of your head okay so there +are two main Frameworks for deriving + + align:start position:0% +are two main Frameworks for deriving + + + align:start position:0% +are two main Frameworks for deriving +estimators one is called the method of + + align:start position:0% +estimators one is called the method of + + + align:start position:0% +estimators one is called the method of +moments and the uh second is called + + align:start position:0% +moments and the uh second is called + + + align:start position:0% +moments and the uh second is called +maximum likelihood estimation okay and + + align:start position:0% +maximum likelihood estimation okay and + + + align:start position:0% +maximum likelihood estimation okay and +in fact we've seen examples of both so + + align:start position:0% +in fact we've seen examples of both so + + + align:start position:0% +in fact we've seen examples of both so +two times the sample mean uh in the + + align:start position:0% +two times the sample mean uh in the + + + align:start position:0% +two times the sample mean uh in the +uniform example is a method of moments + + align:start position:0% +uniform example is a method of moments + + + align:start position:0% +uniform example is a method of moments +estimator and uh the um nth order + + align:start position:0% +estimator and uh the um nth order + + + align:start position:0% +estimator and uh the um nth order +statistic in that same in the uniform + + align:start position:0% +statistic in that same in the uniform + + + align:start position:0% +statistic in that same in the uniform +zero Theta distribution is a maximum + + align:start position:0% +zero Theta distribution is a maximum + + + align:start position:0% +zero Theta distribution is a maximum +likelihood estimator + + align:start position:0% +likelihood estimator + + + align:start position:0% +likelihood estimator +okay and then as I said before a third + + align:start position:0% +okay and then as I said before a third + + + align:start position:0% +okay and then as I said before a third +framework you can think of is to just + + align:start position:0% +framework you can think of is to just + + + align:start position:0% +framework you can think of is to just +come up with something clever off the + + align:start position:0% +come up with something clever off the + + + align:start position:0% +come up with something clever off the +top of your head and that sometimes + + align:start position:0% + + + + align:start position:0% + +works + + align:start position:0% +works + + + align:start position:0% +works +okay okay so let me just give you um + + align:start position:0% +okay okay so let me just give you um + + + align:start position:0% +okay okay so let me just give you um +sort of sketch out what the method of + + align:start position:0% +sort of sketch out what the method of + + + align:start position:0% +sort of sketch out what the method of +moments um uh framework for deriving + + align:start position:0% +moments um uh framework for deriving + + + align:start position:0% +moments um uh framework for deriving +estimators is give you an example of one + + align:start position:0% +estimators is give you an example of one + + + align:start position:0% +estimators is give you an example of one +uh and then do the same for maximum + + align:start position:0% +uh and then do the same for maximum + + + align:start position:0% +uh and then do the same for maximum +likelihood okay so the method of moments + + align:start position:0% +likelihood okay so the method of moments + + + align:start position:0% +likelihood okay so the method of moments +um was developed in in 1894 by Carl + + align:start position:0% +um was developed in in 1894 by Carl + + + align:start position:0% +um was developed in in 1894 by Carl +Pearson that many many people consider + + align:start position:0% +Pearson that many many people consider + + + align:start position:0% +Pearson that many many people consider +to be the father of mathematical + + align:start position:0% +to be the father of mathematical + + + align:start position:0% +to be the father of mathematical +statistics um there's a picture of them + + align:start position:0% +statistics um there's a picture of them + + + align:start position:0% +statistics um there's a picture of them +um and first to tell you what the method + + align:start position:0% +um and first to tell you what the method + + + align:start position:0% +um and first to tell you what the method +of moments uh what method of moments + + align:start position:0% +of moments uh what method of moments + + + align:start position:0% +of moments uh what method of moments +estimation is I've got to define a + + align:start position:0% +estimation is I've got to define a + + + align:start position:0% +estimation is I've got to define a +couple of things so I've got to define + + align:start position:0% +couple of things so I've got to define + + + align:start position:0% +couple of things so I've got to define +population moments and I've got to + + align:start position:0% +population moments and I've got to + + + align:start position:0% +population moments and I've got to +define sample + + align:start position:0% +define sample + + + align:start position:0% +define sample +moments okay so a population moment + + align:start position:0% +moments okay so a population moment + + + align:start position:0% +moments okay so a population moment +we've we've already seen we haven't used + + align:start position:0% +we've we've already seen we haven't used + + + align:start position:0% +we've we've already seen we haven't used +the terminology population moment but uh + + align:start position:0% +the terminology population moment but uh + + + align:start position:0% +the terminology population moment but uh +we've already seen uh the first + + align:start position:0% +we've already seen uh the first + + + align:start position:0% +we've already seen uh the first +population moment about the origin which + + align:start position:0% +population moment about the origin which + + + align:start position:0% +population moment about the origin which +is just the expectation okay the second + + align:start position:0% +is just the expectation okay the second + + + align:start position:0% +is just the expectation okay the second +population moment about the origin is is + + align:start position:0% +population moment about the origin is is + + + align:start position:0% +population moment about the origin is is +the expectation of X squar third + + align:start position:0% +the expectation of X squar third + + + align:start position:0% +the expectation of X squar third +population moment expectation of X cubed + + align:start position:0% +population moment expectation of X cubed + + + align:start position:0% +population moment expectation of X cubed +okay so for any distribution we can just + + align:start position:0% +okay so for any distribution we can just + + + align:start position:0% +okay so for any distribution we can just +you know we can calculate these as + + align:start position:0% +you know we can calculate these as + + + align:start position:0% +you know we can calculate these as +functions of the parameters or we can + + align:start position:0% +functions of the parameters or we can + + + align:start position:0% +functions of the parameters or we can +look them up on Wikipedia or we can look + + align:start position:0% +look them up on Wikipedia or we can look + + + align:start position:0% +look them up on Wikipedia or we can look +them up in the back of our statistics + + align:start position:0% +them up in the back of our statistics + + + align:start position:0% +them up in the back of our statistics +book or whatever um but you know we can + + align:start position:0% +book or whatever um but you know we can + + + align:start position:0% +book or whatever um but you know we can +we can get uh sort of the population + + align:start position:0% +we can get uh sort of the population + + + align:start position:0% +we can get uh sort of the population +moments as functions of the parameters + + align:start position:0% +moments as functions of the parameters + + + align:start position:0% +moments as functions of the parameters +of the distributions okay so what's the + + align:start position:0% +of the distributions okay so what's the + + + align:start position:0% +of the distributions okay so what's the +as a function of of parameters of the + + align:start position:0% +as a function of of parameters of the + + + align:start position:0% +as a function of of parameters of the +distribution what's the first population + + align:start position:0% +distribution what's the first population + + + align:start position:0% +distribution what's the first population +moment of a normal + + align:start position:0% +moment of a normal + + + align:start position:0% +moment of a normal +distribution mu how about of a pan does + + align:start position:0% +distribution mu how about of a pan does + + + align:start position:0% +distribution mu how about of a pan does +anyone remember that Lambda Lambda how + + align:start position:0% +anyone remember that Lambda Lambda how + + + align:start position:0% +anyone remember that Lambda Lambda how +about of a + + align:start position:0% +about of a + + + align:start position:0% +about of a +uniform + + align:start position:0% +uniform + + + align:start position:0% +uniform +z uh to + + align:start position:0% +z uh to + + + align:start position:0% +z uh to +Theta Theta over two right okay so you + + align:start position:0% +Theta Theta over two right okay so you + + + align:start position:0% +Theta Theta over two right okay so you +guys get the idea the sample moments are + + align:start position:0% +guys get the idea the sample moments are + + + align:start position:0% +guys get the idea the sample moments are +just we've seen obviously the first + + align:start position:0% +just we've seen obviously the first + + + align:start position:0% +just we've seen obviously the first +sample moment uh it's just the sample + + align:start position:0% +sample moment uh it's just the sample + + + align:start position:0% +sample moment uh it's just the sample +mean okay the second sample moment is + + align:start position:0% +mean okay the second sample moment is + + + align:start position:0% +mean okay the second sample moment is +the same thing but uh we're going to + + align:start position:0% +the same thing but uh we're going to + + + align:start position:0% +the same thing but uh we're going to +square all of the um the observations + + align:start position:0% +square all of the um the observations + + + align:start position:0% +square all of the um the observations +instead and and so forth you have a + + align:start position:0% +instead and and so forth you have a + + + align:start position:0% +instead and and so forth you have a +question going back to the sample + + align:start position:0% +question going back to the sample + + + align:start position:0% +question going back to the sample +variance that you showed us that was + + align:start position:0% +variance that you showed us that was + + + align:start position:0% +variance that you showed us that was +divided by nus one so is there any like + + align:start position:0% +divided by nus one so is there any like + + + align:start position:0% +divided by nus one so is there any like +inconsistent or like how do you + + align:start position:0% +inconsistent or like how do you + + + align:start position:0% +inconsistent or like how do you +reconcile the fact that the sample + + align:start position:0% +reconcile the fact that the sample + + + align:start position:0% +reconcile the fact that the sample +moments um so the S so the the the + + align:start position:0% +moments um so the S so the the the + + + align:start position:0% +moments um so the S so the the the +sample moment that I showed you was not + + align:start position:0% +sample moment that I showed you was not + + + align:start position:0% +sample moment that I showed you was not +a sample M well first of all uh the it + + align:start position:0% +a sample M well first of all uh the it + + + align:start position:0% +a sample M well first of all uh the it +it was not about the origin it was about + + align:start position:0% +it was not about the origin it was about + + + align:start position:0% +it was not about the origin it was about +the mean so I'm defining sample moments + + align:start position:0% +the mean so I'm defining sample moments + + + align:start position:0% +the mean so I'm defining sample moments +here as I I left I left it out but I + + align:start position:0% +here as I I left I left it out but I + + + align:start position:0% +here as I I left I left it out but I +should have said sample moments about + + align:start position:0% +should have said sample moments about + + + align:start position:0% +should have said sample moments about +the origin so there are two different + + align:start position:0% +the origin so there are two different + + + align:start position:0% +the origin so there are two different +types of moments for a dist sample + + align:start position:0% +types of moments for a dist sample + + + align:start position:0% +types of moments for a dist sample +moments for a distribution one is about + + align:start position:0% +moments for a distribution one is about + + + align:start position:0% +moments for a distribution one is about +the mean and one's about the origin + + align:start position:0% +the mean and one's about the origin + + + align:start position:0% +the mean and one's about the origin +these ones are about the origin and the + + align:start position:0% +these ones are about the origin and the + + + align:start position:0% +these ones are about the origin and the +other thing is that I to be honest I'm + + align:start position:0% +other thing is that I to be honest I'm + + + align:start position:0% +other thing is that I to be honest I'm +not sure the sample + + align:start position:0% +not sure the sample + + + align:start position:0% +not sure the sample +variance uh may + + align:start position:0% +variance uh may + + + align:start position:0% +variance uh may +not I I believe that actually the + + align:start position:0% +not I I believe that actually the + + + align:start position:0% +not I I believe that actually the +definition of the second sample moment + + align:start position:0% +definition of the second sample moment + + + align:start position:0% +definition of the second sample moment +about the mean is one over n it's not 1 + + align:start position:0% +about the mean is one over n it's not 1 + + + align:start position:0% +about the mean is one over n it's not 1 +over n minus one so the sample variance + + align:start position:0% +over n minus one so the sample variance + + + align:start position:0% +over n minus one so the sample variance +is defined differently than the second + + align:start position:0% +is defined differently than the second + + + align:start position:0% +is defined differently than the second +sample moment about the mean and the + + align:start position:0% +sample moment about the mean and the + + + align:start position:0% +sample moment about the mean and the +reason why is that the second sample + + align:start position:0% +reason why is that the second sample + + + align:start position:0% +reason why is that the second sample +moment about the mean is actually a + + align:start position:0% +moment about the mean is actually a + + + align:start position:0% +moment about the mean is actually a +biased estimator of the variance so it's + + align:start position:0% +biased estimator of the variance so it's + + + align:start position:0% +biased estimator of the variance so it's +um yeah thanks for thanks for asking + + align:start position:0% +um yeah thanks for thanks for asking + + + align:start position:0% +um yeah thanks for thanks for asking +that question but yeah there's a no no + + align:start position:0% +that question but yeah there's a no no + + + align:start position:0% +that question but yeah there's a no no +inconsistency Okay so we've got these + + align:start position:0% +inconsistency Okay so we've got these + + + align:start position:0% +inconsistency Okay so we've got these +population moments these you can just + + align:start position:0% +population moments these you can just + + + align:start position:0% +population moments these you can just +think of these as like functions of the + + align:start position:0% +think of these as like functions of the + + + align:start position:0% +think of these as like functions of the +parameters okay and then we've got the + + align:start position:0% +parameters okay and then we've got the + + + align:start position:0% +parameters okay and then we've got the +sample moments and we're going to use + + align:start position:0% +sample moments and we're going to use + + + align:start position:0% +sample moments and we're going to use +those together to derve + + align:start position:0% +those together to derve + + + align:start position:0% +those together to derve +estimators okay so to estimate a + + align:start position:0% +estimators okay so to estimate a + + + align:start position:0% +estimators okay so to estimate a +parameter we equate the first population + + align:start position:0% +parameter we equate the first population + + + align:start position:0% +parameter we equate the first population +moment which is as I said a function of + + align:start position:0% +moment which is as I said a function of + + + align:start position:0% +moment which is as I said a function of +the parameter to the first sample moment + + align:start position:0% +the parameter to the first sample moment + + + align:start position:0% +the parameter to the first sample moment +and then we just solve for the parameter + + align:start position:0% +and then we just solve for the parameter + + + align:start position:0% +and then we just solve for the parameter +so let's do a quick + + align:start position:0% +so let's do a quick + + + align:start position:0% +so let's do a quick +example so this is an example we've + + align:start position:0% +example so this is an example we've + + + align:start position:0% +example so this is an example we've +already seen uh the first population + + align:start position:0% +already seen uh the first population + + + align:start position:0% +already seen uh the first population +moment expectation of X of a uniform 0 + + align:start position:0% +moment expectation of X of a uniform 0 + + + align:start position:0% +moment expectation of X of a uniform 0 +to Theta is just Theta over 2 and the + + align:start position:0% +to Theta is just Theta over 2 and the + + + align:start position:0% +to Theta is just Theta over 2 and the +first sample moment is just 1/ n * the + + align:start position:0% +first sample moment is just 1/ n * the + + + align:start position:0% +first sample moment is just 1/ n * the +sum of the X's so we equate those two + + align:start position:0% +sum of the X's so we equate those two + + + align:start position:0% +sum of the X's so we equate those two +things we have to now stick a hat on the + + align:start position:0% +things we have to now stick a hat on the + + + align:start position:0% +things we have to now stick a hat on the +Theta because it's uh once we once we + + align:start position:0% +Theta because it's uh once we once we + + + align:start position:0% +Theta because it's uh once we once we +equate the sample moment and the + + align:start position:0% +equate the sample moment and the + + + align:start position:0% +equate the sample moment and the +population moment now now we're solving + + align:start position:0% +population moment now now we're solving + + + align:start position:0% +population moment now now we're solving +for an estimator not the parameter we + + align:start position:0% +for an estimator not the parameter we + + + align:start position:0% +for an estimator not the parameter we +stick a hat on on it and then we solve + + align:start position:0% +stick a hat on on it and then we solve + + + align:start position:0% +stick a hat on on it and then we solve +for Theta hat + + align:start position:0% +for Theta hat + + + align:start position:0% +for Theta hat +okay so that's exactly the estimator we + + align:start position:0% +okay so that's exactly the estimator we + + + align:start position:0% +okay so that's exactly the estimator we +saw before and this is just exhibiting + + align:start position:0% +saw before and this is just exhibiting + + + align:start position:0% +saw before and this is just exhibiting +that it is in fact a method of moments + + align:start position:0% +that it is in fact a method of moments + + + align:start position:0% +that it is in fact a method of moments +estimator okay + + align:start position:0% + + + + align:start position:0% + +what if you have more than one parameter + + align:start position:0% +what if you have more than one parameter + + + align:start position:0% +what if you have more than one parameter +estimate so for instance what if you + + align:start position:0% +estimate so for instance what if you + + + align:start position:0% +estimate so for instance what if you +have a normal distribution and you want + + align:start position:0% +have a normal distribution and you want + + + align:start position:0% +have a normal distribution and you want +an estimate of both the mean and the um + + align:start position:0% +an estimate of both the mean and the um + + + align:start position:0% +an estimate of both the mean and the um +the variance from the the normal + + align:start position:0% +the variance from the the normal + + + align:start position:0% +the variance from the the normal +distribution or you have like a binomial + + align:start position:0% +distribution or you have like a binomial + + + align:start position:0% +distribution or you have like a binomial +distribution you want n and p or + + align:start position:0% +distribution you want n and p or + + + align:start position:0% +distribution you want n and p or +something like that well um no problem + + align:start position:0% +something like that well um no problem + + + align:start position:0% +something like that well um no problem +so the method of moments can accommodate + + align:start position:0% +so the method of moments can accommodate + + + align:start position:0% +so the method of moments can accommodate +that you just use as many sample and + + align:start position:0% +that you just use as many sample and + + + align:start position:0% +that you just use as many sample and +population moments as necessary so each + + align:start position:0% +population moments as necessary so each + + + align:start position:0% +population moments as necessary so each +pair of you know sort of a sample moment + + align:start position:0% +pair of you know sort of a sample moment + + + align:start position:0% +pair of you know sort of a sample moment +and a population moment each one of + + align:start position:0% +and a population moment each one of + + + align:start position:0% +and a population moment each one of +those is called a moment + + align:start position:0% +those is called a moment + + + align:start position:0% +those is called a moment +condition and then if you have K + + align:start position:0% +condition and then if you have K + + + align:start position:0% +condition and then if you have K +parameters to estimate you just have K + + align:start position:0% +parameters to estimate you just have K + + + align:start position:0% +parameters to estimate you just have K +moment conditions and then uh that + + align:start position:0% +moment conditions and then uh that + + + align:start position:0% +moment conditions and then uh that +basically means you'll have K equations + + align:start position:0% +basically means you'll have K equations + + + align:start position:0% +basically means you'll have K equations +in K unknowns the K unknowns being the + + align:start position:0% +in K unknowns the K unknowns being the + + + align:start position:0% +in K unknowns the K unknowns being the +all of the parameter with hats on them + + align:start position:0% +all of the parameter with hats on them + + + align:start position:0% +all of the parameter with hats on them +you're you're solving for estimators for + + align:start position:0% +you're you're solving for estimators for + + + align:start position:0% +you're you're solving for estimators for +all those parameters and so then you + + align:start position:0% +all those parameters and so then you + + + align:start position:0% +all those parameters and so then you +just solve those K moment conditions for + + align:start position:0% +just solve those K moment conditions for + + + align:start position:0% +just solve those K moment conditions for +the K PR or for the K + + align:start position:0% +the K PR or for the K + + + align:start position:0% +the K PR or for the K +estimators + + align:start position:0% + + + + align:start position:0% + +okay okay so second framework uh the + + align:start position:0% +okay okay so second framework uh the + + + align:start position:0% +okay okay so second framework uh the +idea for maximum likelihood estimation + + align:start position:0% +idea for maximum likelihood estimation + + + align:start position:0% +idea for maximum likelihood estimation +has been around for a very long time and + + align:start position:0% +has been around for a very long time and + + + align:start position:0% +has been around for a very long time and +uh if you try to sort of figure out what + + align:start position:0% +uh if you try to sort of figure out what + + + align:start position:0% +uh if you try to sort of figure out what +its origin is it's really a little + + align:start position:0% +its origin is it's really a little + + + align:start position:0% +its origin is it's really a little +unclear I think that um uh a lot of um + + align:start position:0% +unclear I think that um uh a lot of um + + + align:start position:0% +unclear I think that um uh a lot of um +sort of historians of Statistics would + + align:start position:0% +sort of historians of Statistics would + + + align:start position:0% +sort of historians of Statistics would +attribute the idea to lrange in the + + align:start position:0% +attribute the idea to lrange in the + + + align:start position:0% +attribute the idea to lrange in the +1770s um but it probably the basic idea + + align:start position:0% +1770s um but it probably the basic idea + + + align:start position:0% +1770s um but it probably the basic idea +probably predated that uh and sort of + + align:start position:0% +probably predated that uh and sort of + + + align:start position:0% +probably predated that uh and sort of +the analytics like proving that maximum + + align:start position:0% +the analytics like proving that maximum + + + align:start position:0% +the analytics like proving that maximum +likelihood estimation was a reasonable + + align:start position:0% +likelihood estimation was a reasonable + + + align:start position:0% +likelihood estimation was a reasonable +thing to do uh that that sort of came + + align:start position:0% +thing to do uh that that sort of came + + + align:start position:0% +thing to do uh that that sort of came +much later around 1930 with ra Fischer + + align:start position:0% +much later around 1930 with ra Fischer + + + align:start position:0% +much later around 1930 with ra Fischer +okay and there's those guys you can + + align:start position:0% +okay and there's those guys you can + + + align:start position:0% +okay and there's those guys you can +probably figure out which one is from + + align:start position:0% +probably figure out which one is from + + + align:start position:0% +probably figure out which one is from +1770s and which one's from the + + align:start position:0% +1770s and which one's from the + + + align:start position:0% +1770s and which one's from the +1930s okay so what is a maximum likel + + align:start position:0% +1930s okay so what is a maximum likel + + + align:start position:0% +1930s okay so what is a maximum likel +Hood estimator well it's the value Theta + + align:start position:0% +Hood estimator well it's the value Theta + + + align:start position:0% +Hood estimator well it's the value Theta +hat which most likely would have + + align:start position:0% +hat which most likely would have + + + align:start position:0% +hat which most likely would have +generated The observed + + align:start position:0% +generated The observed + + + align:start position:0% +generated The observed +sample okay that's why it's called + + align:start position:0% +sample okay that's why it's called + + + align:start position:0% +sample okay that's why it's called +maximum + + align:start position:0% +maximum + + + align:start position:0% +maximum +likelihood okay so what exactly does + + align:start position:0% +likelihood okay so what exactly does + + + align:start position:0% +likelihood okay so what exactly does +this mean how do we how do we find + + align:start position:0% +this mean how do we how do we find + + + align:start position:0% +this mean how do we how do we find +it okay so let's think of it this way so + + align:start position:0% +it okay so let's think of it this way so + + + align:start position:0% +it okay so let's think of it this way so +this is not sort of this is just U + + align:start position:0% +this is not sort of this is just U + + + align:start position:0% +this is not sort of this is just U +motivation this is not exactly this is + + align:start position:0% +motivation this is not exactly this is + + + align:start position:0% +motivation this is not exactly this is +not in in fact how you find a maximum + + align:start position:0% +not in in fact how you find a maximum + + + align:start position:0% +not in in fact how you find a maximum +likelihood estimator but this is going + + align:start position:0% +likelihood estimator but this is going + + + align:start position:0% +likelihood estimator but this is going +to serve as motivation okay so let's + + align:start position:0% +to serve as motivation okay so let's + + + align:start position:0% +to serve as motivation okay so let's +suppose we have a random sample + + align:start position:0% +suppose we have a random sample + + + align:start position:0% +suppose we have a random sample +and we uh want and we know that our + + align:start position:0% +and we uh want and we know that our + + + align:start position:0% +and we uh want and we know that our +random sample is from some particular + + align:start position:0% +random sample is from some particular + + + align:start position:0% +random sample is from some particular +distribution but we don't know which + + align:start position:0% +distribution but we don't know which + + + align:start position:0% +distribution but we don't know which +member or some particular family of + + align:start position:0% +member or some particular family of + + + align:start position:0% +member or some particular family of +distributions but don't know which + + align:start position:0% +distributions but don't know which + + + align:start position:0% +distributions but don't know which +member it is so in other words we know + + align:start position:0% +member it is so in other words we know + + + align:start position:0% +member it is so in other words we know +it has a beta distribution but we don't + + align:start position:0% +it has a beta distribution but we don't + + + align:start position:0% +it has a beta distribution but we don't +know what the parameter of the beta + + align:start position:0% +know what the parameter of the beta + + + align:start position:0% +know what the parameter of the beta +distribution is or we know it's a normal + + align:start position:0% +distribution is or we know it's a normal + + + align:start position:0% +distribution is or we know it's a normal +distribution but we don't know what mu + + align:start position:0% +distribution but we don't know what mu + + + align:start position:0% +distribution but we don't know what mu +and sigma squ are okay so you can think + + align:start position:0% +and sigma squ are okay so you can think + + + align:start position:0% +and sigma squ are okay so you can think +of being able to create a histogram with + + align:start position:0% +of being able to create a histogram with + + + align:start position:0% +of being able to create a histogram with +our random sample okay and this is sort + + align:start position:0% +our random sample okay and this is sort + + + align:start position:0% +our random sample okay and this is sort +of the empirical counterpart of the + + align:start position:0% + + + + align:start position:0% + +PDF on the other side you can think of + + align:start position:0% +PDF on the other side you can think of + + + align:start position:0% +PDF on the other side you can think of +taking this family of distributions that + + align:start position:0% +taking this family of distributions that + + + align:start position:0% +taking this family of distributions that +we're assuming or that we know that our + + align:start position:0% +we're assuming or that we know that our + + + align:start position:0% +we're assuming or that we know that our +uh random sample has come from and + + align:start position:0% +uh random sample has come from and + + + align:start position:0% +uh random sample has come from and +varying the parameter or parameters in + + align:start position:0% +varying the parameter or parameters in + + + align:start position:0% +varying the parameter or parameters in +that distribution that family of + + align:start position:0% +that distribution that family of + + + align:start position:0% +that distribution that family of +distributions and we get sort of all + + align:start position:0% +distributions and we get sort of all + + + align:start position:0% +distributions and we get sort of all +kinds of different possibilities here + + align:start position:0% +kinds of different possibilities here + + + align:start position:0% +kinds of different possibilities here +and presumably we get a Continuum of + + align:start position:0% +and presumably we get a Continuum of + + + align:start position:0% +and presumably we get a Continuum of +possibilities I've just drawn what is + + align:start position:0% +possibilities I've just drawn what is + + + align:start position:0% +possibilities I've just drawn what is +this I've drawn five different + + align:start position:0% +this I've drawn five different + + + align:start position:0% +this I've drawn five different +possibilities here but you know we have + + align:start position:0% +possibilities here but you know we have + + + align:start position:0% +possibilities here but you know we have +sort of an infinite number of + + align:start position:0% +sort of an infinite number of + + + align:start position:0% +sort of an infinite number of +possibilities as we vary the parameter + + align:start position:0% +possibilities as we vary the parameter + + + align:start position:0% +possibilities as we vary the parameter +or parameters of these distribut ions + + align:start position:0% +or parameters of these distribut ions + + + align:start position:0% +or parameters of these distribut ions +okay so where did we get these well as I + + align:start position:0% +okay so where did we get these well as I + + + align:start position:0% +okay so where did we get these well as I +said we're assuming a particular family + + align:start position:0% +said we're assuming a particular family + + + align:start position:0% +said we're assuming a particular family +and then just varying the + + align:start position:0% + + + + align:start position:0% + +parameters so how do we choose which one + + align:start position:0% +parameters so how do we choose which one + + + align:start position:0% +parameters so how do we choose which one +of those well just sort of intuitively + + align:start position:0% +of those well just sort of intuitively + + + align:start position:0% +of those well just sort of intuitively +or graphically we want to choose the one + + align:start position:0% +or graphically we want to choose the one + + + align:start position:0% +or graphically we want to choose the one +that sort of fits our histogram the best + + align:start position:0% +that sort of fits our histogram the best + + + align:start position:0% +that sort of fits our histogram the best +right okay so that's what we + + align:start position:0% +right okay so that's what we + + + align:start position:0% +right okay so that's what we +do we choose the the member of the + + align:start position:0% +do we choose the the member of the + + + align:start position:0% +do we choose the the member of the +family of distributions that's most + + align:start position:0% +family of distributions that's most + + + align:start position:0% +family of distributions that's most +likely to have produced our data so if + + align:start position:0% +likely to have produced our data so if + + + align:start position:0% +likely to have produced our data so if +we chose a member of the family whose + + align:start position:0% +we chose a member of the family whose + + + align:start position:0% +we chose a member of the family whose +shape was much different than our + + align:start position:0% +shape was much different than our + + + align:start position:0% +shape was much different than our +histogram that it's unlikely that it + + align:start position:0% +histogram that it's unlikely that it + + + align:start position:0% +histogram that it's unlikely that it +would that that parameter would have + + align:start position:0% +would that that parameter would have + + + align:start position:0% +would that that parameter would have +produced the data that we saw okay the + + align:start position:0% +produced the data that we saw okay the + + + align:start position:0% +produced the data that we saw okay the +one that fits our histogram most closely + + align:start position:0% +one that fits our histogram most closely + + + align:start position:0% +one that fits our histogram most closely +that's the one that's most likely to + + align:start position:0% +that's the one that's most likely to + + + align:start position:0% +that's the one that's most likely to +have given rise to our + + align:start position:0% +have given rise to our + + + align:start position:0% +have given rise to our +data + + align:start position:0% + + + + align:start position:0% + +okay so Theta half the our maximum + + align:start position:0% +okay so Theta half the our maximum + + + align:start position:0% +okay so Theta half the our maximum +likelihood estimator is the value of the + + align:start position:0% +likelihood estimator is the value of the + + + align:start position:0% +likelihood estimator is the value of the +parameter associated with this + + align:start position:0% +parameter associated with this + + + align:start position:0% +parameter associated with this +particular best fit member of the family + + align:start position:0% +particular best fit member of the family + + + align:start position:0% +particular best fit member of the family +of + + align:start position:0% +of + + + align:start position:0% +of +distributions okay so is that is that + + align:start position:0% +distributions okay so is that is that + + + align:start position:0% +distributions okay so is that is that +sort of concept + + align:start position:0% +sort of concept + + + align:start position:0% +sort of concept +clear even if you don't know how to find + + align:start position:0% +clear even if you don't know how to find + + + align:start position:0% +clear even if you don't know how to find +that yet + + align:start position:0% +that yet + + + align:start position:0% +that yet +okay okay so conceptually makes sense at + + align:start position:0% +okay okay so conceptually makes sense at + + + align:start position:0% +okay okay so conceptually makes sense at +least I hope it + + align:start position:0% +least I hope it + + + align:start position:0% +least I hope it +does operationally how do we go about + + align:start position:0% +does operationally how do we go about + + + align:start position:0% +does operationally how do we go about +this how do we find the one one of a + + align:start position:0% +this how do we find the one one of a + + + align:start position:0% +this how do we find the one one of a +bunch of PDFs that's most likely to have + + align:start position:0% +bunch of PDFs that's most likely to have + + + align:start position:0% +bunch of PDFs that's most likely to have +produced our + + align:start position:0% + + + + align:start position:0% + +data well the key is that we have to + + align:start position:0% +data well the key is that we have to + + + align:start position:0% +data well the key is that we have to +think about the joint PDF of our data in + + align:start position:0% +think about the joint PDF of our data in + + + align:start position:0% +think about the joint PDF of our data in +a somewhat different way okay so we we + + align:start position:0% +a somewhat different way okay so we we + + + align:start position:0% +a somewhat different way okay so we we +know how to if we have a random sample + + align:start position:0% +know how to if we have a random sample + + + align:start position:0% +know how to if we have a random sample +we know how to get the joint PDF of that + + align:start position:0% +we know how to get the joint PDF of that + + + align:start position:0% +we know how to get the joint PDF of that +random sample okay we're just it's just + + align:start position:0% +random sample okay we're just it's just + + + align:start position:0% +random sample okay we're just it's just +the product of the individual PD FS of + + align:start position:0% +the product of the individual PD FS of + + + align:start position:0% +the product of the individual PD FS of +all of the the random variables in our + + align:start position:0% +all of the the random variables in our + + + align:start position:0% +all of the the random variables in our +random sample okay now we think of this + + align:start position:0% +random sample okay now we think of this + + + align:start position:0% +random sample okay now we think of this +joint PDF as the function of the + + align:start position:0% +joint PDF as the function of the + + + align:start position:0% +joint PDF as the function of the +parameters now okay we'd always sort of + + align:start position:0% +parameters now okay we'd always sort of + + + align:start position:0% +parameters now okay we'd always sort of +taken the parameters as given they were + + align:start position:0% +taken the parameters as given they were + + + align:start position:0% +taken the parameters as given they were +just sort of constants in our function + + align:start position:0% +just sort of constants in our function + + + align:start position:0% +just sort of constants in our function +that we sort of took as given now we + + align:start position:0% +that we sort of took as given now we + + + align:start position:0% +that we sort of took as given now we +think of that joint PDF as a function of + + align:start position:0% +think of that joint PDF as a function of + + + align:start position:0% +think of that joint PDF as a function of +those parameters and we're going to + + align:start position:0% +those parameters and we're going to + + + align:start position:0% +those parameters and we're going to +maximize that distrib or that joint PDF + + align:start position:0% +maximize that distrib or that joint PDF + + + align:start position:0% +maximize that distrib or that joint PDF +over the possible values of the pr + + align:start position:0% +over the possible values of the pr + + + align:start position:0% +over the possible values of the pr +parameters + + align:start position:0% +parameters + + + align:start position:0% +parameters +okay okay yes of course and we we'll + + align:start position:0% +okay okay yes of course and we we'll + + + align:start position:0% +okay okay yes of course and we we'll +we'll see a couple of examples as well + + align:start position:0% +we'll see a couple of examples as well + + + align:start position:0% +we'll see a couple of examples as well +but I'm happy to go over this because + + align:start position:0% +but I'm happy to go over this because + + + align:start position:0% +but I'm happy to go over this because +it's a little it's a little subtle it's + + align:start position:0% +it's a little it's a little subtle it's + + + align:start position:0% +it's a little it's a little subtle it's +a little confusing um so basically what + + align:start position:0% +a little confusing um so basically what + + + align:start position:0% +a little confusing um so basically what +we do actually let me go to the next + + align:start position:0% +we do actually let me go to the next + + + align:start position:0% +we do actually let me go to the next +slide yes okay so in other words what we + + align:start position:0% +slide yes okay so in other words what we + + + align:start position:0% +slide yes okay so in other words what we +do is we take the joint PDF of our + + align:start position:0% +do is we take the joint PDF of our + + + align:start position:0% +do is we take the joint PDF of our +random sample we're going to call it + + align:start position:0% +random sample we're going to call it + + + align:start position:0% +random sample we're going to call it +instead of calling it ad joint PDF we're + + align:start position:0% +instead of calling it ad joint PDF we're + + + align:start position:0% +instead of calling it ad joint PDF we're +now going to call it a likelihood + + align:start position:0% +now going to call it a likelihood + + + align:start position:0% +now going to call it a likelihood +function okay that's just suggestive to + + align:start position:0% +function okay that's just suggestive to + + + align:start position:0% +function okay that's just suggestive to +us that we have to think of it in a + + align:start position:0% +us that we have to think of it in a + + + align:start position:0% +us that we have to think of it in a +different way it's exactly the same + + align:start position:0% +different way it's exactly the same + + + align:start position:0% +different way it's exactly the same +thing the likelihood function is the + + align:start position:0% +thing the likelihood function is the + + + align:start position:0% +thing the likelihood function is the +joint PDF of a random sample how do we + + align:start position:0% +joint PDF of a random sample how do we + + + align:start position:0% +joint PDF of a random sample how do we +get this likelihood function well we + + align:start position:0% +get this likelihood function well we + + + align:start position:0% +get this likelihood function well we +just take the product of the individual + + align:start position:0% +just take the product of the individual + + + align:start position:0% +just take the product of the individual +PDFs of all of the guys in our random + + align:start position:0% +PDFs of all of the guys in our random + + + align:start position:0% +PDFs of all of the guys in our random +sample right you guys remember that so + + align:start position:0% +sample right you guys remember that so + + + align:start position:0% +sample right you guys remember that so +these are a what's a random sample it's + + align:start position:0% +these are a what's a random sample it's + + + align:start position:0% +these are a what's a random sample it's +independent identically distributed + + align:start position:0% +independent identically distributed + + + align:start position:0% +independent identically distributed +random variables to get the joint + + align:start position:0% +random variables to get the joint + + + align:start position:0% +random variables to get the joint +distribution of independent identically + + align:start position:0% +distribution of independent identically + + + align:start position:0% +distribution of independent identically +distributed random variables you just + + align:start position:0% +distributed random variables you just + + + align:start position:0% +distributed random variables you just +take their their distribution and you + + align:start position:0% +take their their distribution and you + + + align:start position:0% +take their their distribution and you +multiply them together because they're + + align:start position:0% +multiply them together because they're + + + align:start position:0% +multiply them together because they're +independent okay so this is the joint + + align:start position:0% +independent okay so this is the joint + + + align:start position:0% +independent okay so this is the joint +PDF of our random sample we're going to + + align:start position:0% +PDF of our random sample we're going to + + + align:start position:0% +PDF of our random sample we're going to +re label that the likelihood function + + align:start position:0% +re label that the likelihood function + + + align:start position:0% +re label that the likelihood function +and we're going to think of the + + align:start position:0% +and we're going to think of the + + + align:start position:0% +and we're going to think of the +likelihood function as being a function + + align:start position:0% +likelihood function as being a function + + + align:start position:0% +likelihood function as being a function +of theta given the data as as opposed to + + align:start position:0% +of theta given the data as as opposed to + + + align:start position:0% +of theta given the data as as opposed to +the other way around and then we're + + align:start position:0% +the other way around and then we're + + + align:start position:0% +the other way around and then we're +going to map maximize that likelihood + + align:start position:0% +going to map maximize that likelihood + + + align:start position:0% +going to map maximize that likelihood +function with respect to these + + align:start position:0% +function with respect to these + + + align:start position:0% +function with respect to these +parameters + + align:start position:0% + + + + align:start position:0% + +Theta + + align:start position:0% +Theta + + + align:start position:0% +Theta +okay okay so like I said I will I have a + + align:start position:0% +okay okay so like I said I will I have a + + + align:start position:0% +okay okay so like I said I will I have a +couple of + + align:start position:0% + + + + align:start position:0% + +examples okay and this actually just + + align:start position:0% +examples okay and this actually just + + + align:start position:0% +examples okay and this actually just +emphasizes what we said before so we've + + align:start position:0% +emphasizes what we said before so we've + + + align:start position:0% +emphasizes what we said before so we've +got this likelihood function we just + + align:start position:0% +got this likelihood function we just + + + align:start position:0% +got this likelihood function we just +maximize it over all possible values of + + align:start position:0% +maximize it over all possible values of + + + align:start position:0% +maximize it over all possible values of +theta and the one thing to keep in mind + + align:start position:0% +theta and the one thing to keep in mind + + + align:start position:0% +theta and the one thing to keep in mind +I don't for this class you don't really + + align:start position:0% +I don't for this class you don't really + + + align:start position:0% +I don't for this class you don't really +have to worry about this but when you if + + align:start position:0% +have to worry about this but when you if + + + align:start position:0% +have to worry about this but when you if +you go out of this class and you + + align:start position:0% +you go out of this class and you + + + align:start position:0% +you go out of this class and you +encounter uh maximum likelihood in the + + align:start position:0% +encounter uh maximum likelihood in the + + + align:start position:0% +encounter uh maximum likelihood in the +larger world then you're going to have + + align:start position:0% +larger world then you're going to have + + + align:start position:0% +larger world then you're going to have +to realize that a lot of times what we + + align:start position:0% +to realize that a lot of times what we + + + align:start position:0% +to realize that a lot of times what we +do instead of maximizing the likelihood + + align:start position:0% +do instead of maximizing the likelihood + + + align:start position:0% +do instead of maximizing the likelihood +function is we maximize the log + + align:start position:0% +function is we maximize the log + + + align:start position:0% +function is we maximize the log +likelihood function so that's a + + align:start position:0% +likelihood function so that's a + + + align:start position:0% +likelihood function so that's a +perfectly fine thing to do the whatever + + align:start position:0% +perfectly fine thing to do the whatever + + + align:start position:0% +perfectly fine thing to do the whatever +maximizes the likelihood function is + + align:start position:0% +maximizes the likelihood function is + + + align:start position:0% +maximizes the likelihood function is +going to maximize any monotonic + + align:start position:0% +going to maximize any monotonic + + + align:start position:0% +going to maximize any monotonic +transformation of the likelihood + + align:start position:0% +transformation of the likelihood + + + align:start position:0% +transformation of the likelihood +function so it's fine to take a log the + + align:start position:0% +function so it's fine to take a log the + + + align:start position:0% +function so it's fine to take a log the +reason we do it is computationally it + + align:start position:0% +reason we do it is computationally it + + + align:start position:0% +reason we do it is computationally it +just is much easier typically to + + align:start position:0% +just is much easier typically to + + + align:start position:0% +just is much easier typically to +maximize the log likelihood function + + align:start position:0% +maximize the log likelihood function + + + align:start position:0% +maximize the log likelihood function +okay so you sort of go out into the + + align:start position:0% +okay so you sort of go out into the + + + align:start position:0% +okay so you sort of go out into the +broader world you will encounter log + + align:start position:0% +broader world you will encounter log + + + align:start position:0% +broader world you will encounter log +likelihood functions not likelihood + + align:start position:0% +likelihood functions not likelihood + + + align:start position:0% +likelihood functions not likelihood +functions and that's why + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +okay so uh it's good practice um I'm not + + align:start position:0% +okay so uh it's good practice um I'm not + + + align:start position:0% +okay so uh it's good practice um I'm not +necessarily saying you guys have to do + + align:start position:0% +necessarily saying you guys have to do + + + align:start position:0% +necessarily saying you guys have to do +it but it's good practice If you're sort + + align:start position:0% +it but it's good practice If you're sort + + + align:start position:0% +it but it's good practice If you're sort +of interested in in this kind of um you + + align:start position:0% +of interested in in this kind of um you + + + align:start position:0% +of interested in in this kind of um you +know in these kinds of techniques to + + align:start position:0% +know in these kinds of techniques to + + + align:start position:0% +know in these kinds of techniques to +take uh to write down some joint PDFs uh + + align:start position:0% +take uh to write down some joint PDFs uh + + + align:start position:0% +take uh to write down some joint PDFs uh +maybe take the logs to make computation + + align:start position:0% +maybe take the logs to make computation + + + align:start position:0% +maybe take the logs to make computation +easier take the derivative with respect + + align:start position:0% +easier take the derivative with respect + + + align:start position:0% +easier take the derivative with respect +to Theta set the derivatives equal to + + align:start position:0% +to Theta set the derivatives equal to + + + align:start position:0% +to Theta set the derivatives equal to +zero solve for the maximum likelihood + + align:start position:0% +zero solve for the maximum likelihood + + + align:start position:0% +zero solve for the maximum likelihood +estimators um you certainly can do that + + align:start position:0% +estimators um you certainly can do that + + + align:start position:0% +estimators um you certainly can do that +we're not going to do it here okay what + + align:start position:0% +we're not going to do it here okay what + + + align:start position:0% +we're not going to do it here okay what +I'm going to do instead is I'm going to + + align:start position:0% +I'm going to do instead is I'm going to + + + align:start position:0% +I'm going to do instead is I'm going to +do a couple of examples that are both + + align:start position:0% +do a couple of examples that are both + + + align:start position:0% +do a couple of examples that are both +unusual in that they can't can't be + + align:start position:0% +unusual in that they can't can't be + + + align:start position:0% +unusual in that they can't can't be +solved this way because their Maxim + + align:start position:0% +solved this way because their Maxim + + + align:start position:0% +solved this way because their Maxim +their Maxima are not at a point where + + align:start position:0% +their Maxima are not at a point where + + + align:start position:0% +their Maxima are not at a point where +the likelihood function is + + align:start position:0% +the likelihood function is + + + align:start position:0% +the likelihood function is +differentiable but then also don't we + + align:start position:0% +differentiable but then also don't we + + + align:start position:0% +differentiable but then also don't we +don't have to sort of get bogged down + + align:start position:0% +don't have to sort of get bogged down + + + align:start position:0% +don't have to sort of get bogged down +with all the computation so I think + + align:start position:0% +with all the computation so I think + + + align:start position:0% +with all the computation so I think +they're kind of easier examples to to + + align:start position:0% +they're kind of easier examples to to + + + align:start position:0% +they're kind of easier examples to to +show you I think + + align:start position:0% +show you I think + + + align:start position:0% +show you I think +okay so do we guess what do we think the + + align:start position:0% +okay so do we guess what do we think the + + + align:start position:0% +okay so do we guess what do we think the +PDFs are going to be and then we do good + + align:start position:0% +PDFs are going to be and then we do good + + + align:start position:0% +PDFs are going to be and then we do good +question so the question was do we guess + + align:start position:0% +question so the question was do we guess + + + align:start position:0% +question so the question was do we guess +what the PDF is so sometimes we may + + align:start position:0% +what the PDF is so sometimes we may + + + align:start position:0% +what the PDF is so sometimes we may +know when why do we know I don't know + + align:start position:0% +know when why do we know I don't know + + + align:start position:0% +know when why do we know I don't know +maybe we're engineers and we've sort of + + align:start position:0% +maybe we're engineers and we've sort of + + + align:start position:0% +maybe we're engineers and we've sort of +worked in uh you know sort of a + + align:start position:0% +worked in uh you know sort of a + + + align:start position:0% +worked in uh you know sort of a +particular field for our entire careers + + align:start position:0% +particular field for our entire careers + + + align:start position:0% +particular field for our entire careers +and we know that the you know sort of + + align:start position:0% +and we know that the you know sort of + + + align:start position:0% +and we know that the you know sort of +random draws from this par you know like + + align:start position:0% +random draws from this par you know like + + + align:start position:0% +random draws from this par you know like +from some random event that happens uh + + align:start position:0% +from some random event that happens uh + + + align:start position:0% +from some random event that happens uh +with this particular machine always has + + align:start position:0% +with this particular machine always has + + + align:start position:0% +with this particular machine always has +an exponential distribution and we just + + align:start position:0% +an exponential distribution and we just + + + align:start position:0% +an exponential distribution and we just +don't know what the parameter is but we + + align:start position:0% +don't know what the parameter is but we + + + align:start position:0% +don't know what the parameter is but we +know you know we just know from vast + + align:start position:0% +know you know we just know from vast + + + align:start position:0% +know you know we just know from vast +years of experience it's going to be + + align:start position:0% +years of experience it's going to be + + + align:start position:0% +years of experience it's going to be +exponential IAL or maybe we have a + + align:start position:0% +exponential IAL or maybe we have a + + + align:start position:0% +exponential IAL or maybe we have a +theoretical reason to believe that there + + align:start position:0% +theoretical reason to believe that there + + + align:start position:0% +theoretical reason to believe that there +is a particular distribution that's + + align:start position:0% +is a particular distribution that's + + + align:start position:0% +is a particular distribution that's +giving rise to um the random sample or + + align:start position:0% +giving rise to um the random sample or + + + align:start position:0% +giving rise to um the random sample or +sometimes we just guess so it's it it + + align:start position:0% +sometimes we just guess so it's it it + + + align:start position:0% +sometimes we just guess so it's it it +just depends a lot on the problem + + align:start position:0% +just depends a lot on the problem + + + align:start position:0% +just depends a lot on the problem +whether how confident we are about the + + align:start position:0% +whether how confident we are about the + + + align:start position:0% +whether how confident we are about the +the distribution the underlying + + align:start position:0% +the distribution the underlying + + + align:start position:0% +the distribution the underlying +distribution + + align:start position:0% +distribution + + + align:start position:0% +distribution +so okay so I said we we'll do a couple + + align:start position:0% +so okay so I said we we'll do a couple + + + align:start position:0% +so okay so I said we we'll do a couple +of examples but I'm going to do ones + + align:start position:0% +of examples but I'm going to do ones + + + align:start position:0% +of examples but I'm going to do ones +that don't involve the standard you know + + align:start position:0% +that don't involve the standard you know + + + align:start position:0% +that don't involve the standard you know +sort of taking the log of the likelihood + + align:start position:0% +sort of taking the log of the likelihood + + + align:start position:0% +sort of taking the log of the likelihood +function uh setting uh you know sort of + + align:start position:0% +function uh setting uh you know sort of + + + align:start position:0% +function uh setting uh you know sort of +taking derivative with respect to Theta + + align:start position:0% +taking derivative with respect to Theta + + + align:start position:0% +taking derivative with respect to Theta +setting the derivative equal to zero Etc + + align:start position:0% +setting the derivative equal to zero Etc + + + align:start position:0% +setting the derivative equal to zero Etc +I'm going to do some kind of + + align:start position:0% +I'm going to do some kind of + + + align:start position:0% +I'm going to do some kind of +non-standard examples + + align:start position:0% +non-standard examples + + + align:start position:0% +non-standard examples +instead okay so back + + align:start position:0% +instead okay so back + + + align:start position:0% +instead okay so back +to uh this sort of uniform zero Theta + + align:start position:0% +to uh this sort of uniform zero Theta + + + align:start position:0% +to uh this sort of uniform zero Theta +example remember what the maximum + + align:start position:0% +example remember what the maximum + + + align:start position:0% +example remember what the maximum +likelihood estimator from + + align:start position:0% +likelihood estimator from + + + align:start position:0% +likelihood estimator from +um uh what the sorry remember what the I + + align:start position:0% +um uh what the sorry remember what the I + + + align:start position:0% +um uh what the sorry remember what the I +told you I didn't show you obviously but + + align:start position:0% +told you I didn't show you obviously but + + + align:start position:0% +told you I didn't show you obviously but +remember what the maximum likelihood + + align:start position:0% +remember what the maximum likelihood + + + align:start position:0% +remember what the maximum likelihood +estimator for this + + align:start position:0% +estimator for this + + + align:start position:0% +estimator for this +is It's the nth order + + align:start position:0% +is It's the nth order + + + align:start position:0% +is It's the nth order +statistic that's the that's the uh + + align:start position:0% +statistic that's the that's the uh + + + align:start position:0% +statistic that's the that's the uh +expectation of of that estimator but so + + align:start position:0% +expectation of of that estimator but so + + + align:start position:0% +expectation of of that estimator but so +the the maximum likelihood estimator I + + align:start position:0% +the the maximum likelihood estimator I + + + align:start position:0% +the the maximum likelihood estimator I +just said it verbally it wasn't on the + + align:start position:0% +just said it verbally it wasn't on the + + + align:start position:0% +just said it verbally it wasn't on the +slide but I said that that in fact it's + + align:start position:0% +slide but I said that that in fact it's + + + align:start position:0% +slide but I said that that in fact it's +the the nth order + + align:start position:0% +the the nth order + + + align:start position:0% +the the nth order +statistic okay or I think I did okay so + + align:start position:0% +statistic okay or I think I did okay so + + + align:start position:0% +statistic okay or I think I did okay so +so let's figure that out let's verify + + align:start position:0% +so let's figure that out let's verify + + + align:start position:0% +so let's figure that out let's verify +that in fact that is the maximum + + align:start position:0% +that in fact that is the maximum + + + align:start position:0% +that in fact that is the maximum +likelihood estimator okay so what do we + + align:start position:0% +likelihood estimator okay so what do we + + + align:start position:0% +likelihood estimator okay so what do we +do we first have to write down the + + align:start position:0% +do we first have to write down the + + + align:start position:0% +do we first have to write down the +likelihood function how do we get the + + align:start position:0% +likelihood function how do we get the + + + align:start position:0% +likelihood function how do we get the +likelihood function it's just the joint + + align:start position:0% +likelihood function it's just the joint + + + align:start position:0% +likelihood function it's just the joint +PDF of our random sample okay so we have + + align:start position:0% +PDF of our random sample okay so we have + + + align:start position:0% +PDF of our random sample okay so we have +each of our each of the + + align:start position:0% +each of our each of the + + + align:start position:0% +each of our each of the +individual members of the random sample + + align:start position:0% +individual members of the random sample + + + align:start position:0% +individual members of the random sample +has this distribution one over Theta for + + align:start position:0% +has this distribution one over Theta for + + + align:start position:0% +has this distribution one over Theta for +X in Zer to Theta and zero + + align:start position:0% +X in Zer to Theta and zero + + + align:start position:0% +X in Zer to Theta and zero +otherwise okay everyone agrees to + + align:start position:0% +otherwise okay everyone agrees to + + + align:start position:0% +otherwise okay everyone agrees to +that + + align:start position:0% +that + + + align:start position:0% +that +so let's think back to the definition of + + align:start position:0% +so let's think back to the definition of + + + align:start position:0% +so let's think back to the definition of +the maximum likelihood + + align:start position:0% +the maximum likelihood + + + align:start position:0% +the maximum likelihood +estimator it being the parameter that's + + align:start position:0% +estimator it being the parameter that's + + + align:start position:0% +estimator it being the parameter that's +most likely to have given rise to the + + align:start position:0% +most likely to have given rise to the + + + align:start position:0% +most likely to have given rise to the +sample that we observed + + align:start position:0% +sample that we observed + + + align:start position:0% +sample that we observed +okay why so I say here I claim here that + + align:start position:0% +okay why so I say here I claim here that + + + align:start position:0% +okay why so I say here I claim here that +we obviously would not pick any Theta + + align:start position:0% +we obviously would not pick any Theta + + + align:start position:0% +we obviously would not pick any Theta +hat less than the nth order statistic + + align:start position:0% +hat less than the nth order statistic + + + align:start position:0% +hat less than the nth order statistic +why is that given the definition of the + + align:start position:0% +why is that given the definition of the + + + align:start position:0% +why is that given the definition of the +maximum likelihood + + align:start position:0% +maximum likelihood + + + align:start position:0% +maximum likelihood +estimator um Wella is maximum so + + align:start position:0% +estimator um Wella is maximum so + + + align:start position:0% +estimator um Wella is maximum so +there's like a greater value that shows + + align:start position:0% +there's like a greater value that shows + + + align:start position:0% +there's like a greater value that shows +up in the random sample it can't it + + align:start position:0% +up in the random sample it can't it + + + align:start position:0% +up in the random sample it can't it +cannot have happened right it's it's a + + align:start position:0% +cannot have happened right it's it's a + + + align:start position:0% +cannot have happened right it's it's a +probability zero event so let me just + + align:start position:0% +probability zero event so let me just + + + align:start position:0% +probability zero event so let me just +draw a quick picture to + + align:start position:0% + + + + align:start position:0% + +illustrate okay so here's our + + align:start position:0% +illustrate okay so here's our + + + align:start position:0% +illustrate okay so here's our +distribution Theta is + + align:start position:0% +distribution Theta is + + + align:start position:0% +distribution Theta is +unknown if we were to choose so so we + + align:start position:0% +unknown if we were to choose so so we + + + align:start position:0% +unknown if we were to choose so so we +have you know sort of a random sample + + align:start position:0% +have you know sort of a random sample + + + align:start position:0% +have you know sort of a random sample +chosen from this the entire random + + align:start position:0% +chosen from this the entire random + + + align:start position:0% +chosen from this the entire random +sample has to be less than Theta okay + + align:start position:0% +sample has to be less than Theta okay + + + align:start position:0% +sample has to be less than Theta okay +just just has to be I mean that's how + + align:start position:0% +just just has to be I mean that's how + + + align:start position:0% +just just has to be I mean that's how +that's how the problem is set up so + + align:start position:0% +that's how the problem is set up so + + + align:start position:0% +that's how the problem is set up so +let's suppose we + + align:start position:0% +let's suppose we + + + align:start position:0% +let's suppose we +have + + align:start position:0% +have + + + align:start position:0% +have +or actually maybe what I'll do is erase + + align:start position:0% +or actually maybe what I'll do is erase + + + align:start position:0% +or actually maybe what I'll do is erase +this part and we + + align:start position:0% +this part and we + + + align:start position:0% +this part and we +have an nth order statistic we would + + align:start position:0% +have an nth order statistic we would + + + align:start position:0% +have an nth order statistic we would +never choose a guess for Theta below the + + align:start position:0% +never choose a guess for Theta below the + + + align:start position:0% +never choose a guess for Theta below the +nth order statistic because that would + + align:start position:0% + + + + align:start position:0% + +suggest a situation like this that we + + align:start position:0% +suggest a situation like this that we + + + align:start position:0% +suggest a situation like this that we +know can't happen Okay does everyone + + align:start position:0% +know can't happen Okay does everyone + + + align:start position:0% +know can't happen Okay does everyone +understand + + align:start position:0% + + + + align:start position:0% + +that so Theta always has to be at least + + align:start position:0% +that so Theta always has to be at least + + + align:start position:0% +that so Theta always has to be at least +as big as the anthor + + align:start position:0% +as big as the anthor + + + align:start position:0% +as big as the anthor +statistic or Theta + + align:start position:0% +statistic or Theta + + + align:start position:0% +statistic or Theta +hat okay so now we've got the PDF of + + align:start position:0% +hat okay so now we've got the PDF of + + + align:start position:0% +hat okay so now we've got the PDF of +each individual guy in the random sample + + align:start position:0% +each individual guy in the random sample + + + align:start position:0% +each individual guy in the random sample +from that since we know that they're + + align:start position:0% +from that since we know that they're + + + align:start position:0% +from that since we know that they're +independent we can write down the + + align:start position:0% +independent we can write down the + + + align:start position:0% +independent we can write down the +likelihood function which is also the + + align:start position:0% +likelihood function which is also the + + + align:start position:0% +likelihood function which is also the +The Joint PDF of the random sample so + + align:start position:0% +The Joint PDF of the random sample so + + + align:start position:0% +The Joint PDF of the random sample so +that's just remember it's the product of + + align:start position:0% +that's just remember it's the product of + + + align:start position:0% +that's just remember it's the product of +all of the individual PDFs so it's just + + align:start position:0% +all of the individual PDFs so it's just + + + align:start position:0% +all of the individual PDFs so it's just +one over Theta raised to the n for all X + + align:start position:0% +one over Theta raised to the n for all X + + + align:start position:0% +one over Theta raised to the n for all X +or for X subis in this interval and it's + + align:start position:0% +or for X subis in this interval and it's + + + align:start position:0% +or for X subis in this interval and it's +going to be zero otherwise + + align:start position:0% +going to be zero otherwise + + + align:start position:0% +going to be zero otherwise +okay now we can actually restate this um + + align:start position:0% +okay now we can actually restate this um + + + align:start position:0% +okay now we can actually restate this um +condition here instead of saying + + align:start position:0% +condition here instead of saying + + + align:start position:0% +condition here instead of saying +XI in 0 to Theta for IAL 1 to n we can + + align:start position:0% +XI in 0 to Theta for IAL 1 to n we can + + + align:start position:0% +XI in 0 to Theta for IAL 1 to n we can +just say + + align:start position:0% +just say + + + align:start position:0% +just say +instead we can just say instead that's + + align:start position:0% +instead we can just say instead that's + + + align:start position:0% +instead we can just say instead that's +the same as the nth order statistic + + align:start position:0% +the same as the nth order statistic + + + align:start position:0% +the same as the nth order statistic +being less than + + align:start position:0% +being less than + + + align:start position:0% +being less than +Theta okay just equivalent it's an + + align:start position:0% +Theta okay just equivalent it's an + + + align:start position:0% +Theta okay just equivalent it's an +equivalent statement you can say all of + + align:start position:0% +equivalent statement you can say all of + + + align:start position:0% +equivalent statement you can say all of +the X's are in zero in in in the + + align:start position:0% +the X's are in zero in in in the + + + align:start position:0% +the X's are in zero in in in the +interval zero to Theta or the biggest X + + align:start position:0% +interval zero to Theta or the biggest X + + + align:start position:0% +interval zero to Theta or the biggest X +is less than Theta okay so we can say we + + align:start position:0% +is less than Theta okay so we can say we + + + align:start position:0% +is less than Theta okay so we can say we +can say it like that + + align:start position:0% +can say it like that + + + align:start position:0% +can say it like that +instead + + align:start position:0% + + + + align:start position:0% + +okay and so what is the value that + + align:start position:0% +okay and so what is the value that + + + align:start position:0% +okay and so what is the value that +maximizes this likelihood function it is + + align:start position:0% +maximizes this likelihood function it is + + + align:start position:0% +maximizes this likelihood function it is +in fact the anth order + + align:start position:0% +in fact the anth order + + + align:start position:0% +in fact the anth order +statistic so + + align:start position:0% +statistic so + + + align:start position:0% +statistic so +graphically let me show you it might not + + align:start position:0% +graphically let me show you it might not + + + align:start position:0% +graphically let me show you it might not +be 100% clear when you see it in this + + align:start position:0% +be 100% clear when you see it in this + + + align:start position:0% +be 100% clear when you see it in this +form I hope when I show you graphically + + align:start position:0% +form I hope when I show you graphically + + + align:start position:0% +form I hope when I show you graphically +it will become more clear okay why is it + + align:start position:0% +it will become more clear okay why is it + + + align:start position:0% +it will become more clear okay why is it +that the that this function is maximized + + align:start position:0% +that the that this function is maximized + + + align:start position:0% +that the that this function is maximized +at the nth order statistic so this + + align:start position:0% +at the nth order statistic so this + + + align:start position:0% +at the nth order statistic so this +likelihood function is equal to zero for + + align:start position:0% +likelihood function is equal to zero for + + + align:start position:0% +likelihood function is equal to zero for +all values up until the nth order + + align:start position:0% +all values up until the nth order + + + align:start position:0% +all values up until the nth order +statistic okay think of the likelihood + + align:start position:0% +statistic okay think of the likelihood + + + align:start position:0% +statistic okay think of the likelihood +function think of this now instead of + + align:start position:0% +function think of this now instead of + + + align:start position:0% +function think of this now instead of +being a joint PDF of the random sample + + align:start position:0% +being a joint PDF of the random sample + + + align:start position:0% +being a joint PDF of the random sample +this is a function of theta okay so + + align:start position:0% +this is a function of theta okay so + + + align:start position:0% +this is a function of theta okay so +basically what it's saying is this the + + align:start position:0% +basically what it's saying is this the + + + align:start position:0% +basically what it's saying is this the +function is equal to this if Theta is + + align:start position:0% +function is equal to this if Theta is + + + align:start position:0% +function is equal to this if Theta is +greater than the nth order statistic and + + align:start position:0% +greater than the nth order statistic and + + + align:start position:0% +greater than the nth order statistic and +it's equal to zero otherwise so for any + + align:start position:0% +it's equal to zero otherwise so for any + + + align:start position:0% +it's equal to zero otherwise so for any +values of theta less than the norder + + align:start position:0% +values of theta less than the norder + + + align:start position:0% +values of theta less than the norder +statistic this function is equal to zero + + align:start position:0% +statistic this function is equal to zero + + + align:start position:0% +statistic this function is equal to zero +okay so off to the left it's equal to + + align:start position:0% +okay so off to the left it's equal to + + + align:start position:0% +okay so off to the left it's equal to +zero then starting at the nth or + + align:start position:0% +zero then starting at the nth or + + + align:start position:0% +zero then starting at the nth or +statistic let me flip back again it's + + align:start position:0% +statistic let me flip back again it's + + + align:start position:0% +statistic let me flip back again it's +just equal to 1 over Theta to the n so + + align:start position:0% +just equal to 1 over Theta to the n so + + + align:start position:0% +just equal to 1 over Theta to the n so +when we graph it in Theta space like + + align:start position:0% +when we graph it in Theta space like + + + align:start position:0% +when we graph it in Theta space like +this we get that it's equal to zero + + align:start position:0% +this we get that it's equal to zero + + + align:start position:0% +this we get that it's equal to zero +until you get to the anth order + + align:start position:0% +until you get to the anth order + + + align:start position:0% +until you get to the anth order +statistic then it jumps up to one over + + align:start position:0% +statistic then it jumps up to one over + + + align:start position:0% +statistic then it jumps up to one over +Theta to the n and then it you know as + + align:start position:0% +Theta to the n and then it you know as + + + align:start position:0% +Theta to the n and then it you know as +it declines as Theta gets gets larger + + align:start position:0% +it declines as Theta gets gets larger + + + align:start position:0% +it declines as Theta gets gets larger +okay so this is maximized at the inth + + align:start position:0% +okay so this is maximized at the inth + + + align:start position:0% +okay so this is maximized at the inth +order + + align:start position:0% + + + + align:start position:0% + +statistic okay + + align:start position:0% +statistic okay + + + align:start position:0% +statistic okay +questions does this make + + align:start position:0% +questions does this make + + + align:start position:0% +questions does this make +sense and + + align:start position:0% + + + + align:start position:0% + +than n yeah yeah exactly + + align:start position:0% + + + + align:start position:0% + +yeah yeah because it's just the sample + + align:start position:0% +yeah yeah because it's just the sample + + + align:start position:0% +yeah yeah because it's just the sample +size oh I guess the other thing I want + + align:start position:0% +size oh I guess the other thing I want + + + align:start position:0% +size oh I guess the other thing I want +to say about is you can probably see now + + align:start position:0% +to say about is you can probably see now + + + align:start position:0% +to say about is you can probably see now +by looking at the picture why uh we + + align:start position:0% +by looking at the picture why uh we + + + align:start position:0% +by looking at the picture why uh we +didn't solve this by writing down the + + align:start position:0% +didn't solve this by writing down the + + + align:start position:0% +didn't solve this by writing down the +likelihood function taking the uh + + align:start position:0% +likelihood function taking the uh + + + align:start position:0% +likelihood function taking the uh +derivative with respect to Theta setting + + align:start position:0% +derivative with respect to Theta setting + + + align:start position:0% +derivative with respect to Theta setting +the derivative equal to zero Etc because + + align:start position:0% +the derivative equal to zero Etc because + + + align:start position:0% +the derivative equal to zero Etc because +in fact it's not differentiable at the + + align:start position:0% +in fact it's not differentiable at the + + + align:start position:0% +in fact it's not differentiable at the +max so if we had tried to do that we + + align:start position:0% +max so if we had tried to do that we + + + align:start position:0% +max so if we had tried to do that we +would have run into some trouble + + align:start position:0% +would have run into some trouble + + + align:start position:0% +would have run into some trouble +okay okay second + + align:start position:0% +okay okay second + + + align:start position:0% +okay okay second +example let uh xabi uh be IID uniform Z + + align:start position:0% +example let uh xabi uh be IID uniform Z + + + align:start position:0% +example let uh xabi uh be IID uniform Z +or sorry Theta minus 12 to Theta +2 so + + align:start position:0% + + + + align:start position:0% + +here we again have a uniform + + align:start position:0% +here we again have a uniform + + + align:start position:0% +here we again have a uniform +distribution it's not the length of the + + align:start position:0% +distribution it's not the length of the + + + align:start position:0% +distribution it's not the length of the +interval that's unknown we know that the + + align:start position:0% +interval that's unknown we know that the + + + align:start position:0% +interval that's unknown we know that the +interval is length one it's just the + + align:start position:0% +interval is length one it's just the + + + align:start position:0% +interval is length one it's just the +location of the interval that's unknown + + align:start position:0% +location of the interval that's unknown + + + align:start position:0% +location of the interval that's unknown +so the parameter Theta is determining + + align:start position:0% +so the parameter Theta is determining + + + align:start position:0% +so the parameter Theta is determining +the location of this interval okay + + align:start position:0% + + + + align:start position:0% + +so this is Theta -2 up to Theta + + + align:start position:0% +so this is Theta -2 up to Theta + + + + align:start position:0% +so this is Theta -2 up to Theta + +12 okay so this is is our our uh uniform + + align:start position:0% +12 okay so this is is our our uh uniform + + + align:start position:0% +12 okay so this is is our our uh uniform +distribution we're interested in + + align:start position:0% +distribution we're interested in + + + align:start position:0% +distribution we're interested in +estimating the unknown parameter Theta + + align:start position:0% +estimating the unknown parameter Theta + + + align:start position:0% +estimating the unknown parameter Theta +the unknown parameter Theta just + + align:start position:0% +the unknown parameter Theta just + + + align:start position:0% +the unknown parameter Theta just +determines the location of this interval + + align:start position:0% +determines the location of this interval + + + align:start position:0% +determines the location of this interval +okay and since the interval is is uh + + align:start position:0% +okay and since the interval is is uh + + + align:start position:0% +okay and since the interval is is uh +length one then the PDF is always equal + + align:start position:0% +length one then the PDF is always equal + + + align:start position:0% +length one then the PDF is always equal +to one uh in the interval of zero + + align:start position:0% + + + + align:start position:0% + +otherwise so let's write down the + + align:start position:0% +otherwise so let's write down the + + + align:start position:0% +otherwise so let's write down the +likelihood function well this one we + + align:start position:0% +likelihood function well this one we + + + align:start position:0% +likelihood function well this one we +have to be a little clever about we have + + align:start position:0% +have to be a little clever about we have + + + align:start position:0% +have to be a little clever about we have +to sort of think about it um when we + + align:start position:0% +to sort of think about it um when we + + + align:start position:0% +to sort of think about it um when we +write it down so obviously the + + align:start position:0% +write it down so obviously the + + + align:start position:0% +write it down so obviously the +likelihood fun so one raed to the nth + + align:start position:0% +likelihood fun so one raed to the nth + + + align:start position:0% +likelihood fun so one raed to the nth +power is just equal to one but then we + + align:start position:0% +power is just equal to one but then we + + + align:start position:0% +power is just equal to one but then we +have what we have to be clever about is + + align:start position:0% +have what we have to be clever about is + + + align:start position:0% +have what we have to be clever about is +these uh bounds here okay and so let me + + align:start position:0% +these uh bounds here okay and so let me + + + align:start position:0% +these uh bounds here okay and so let me +go through uh the explanation of how we + + align:start position:0% +go through uh the explanation of how we + + + align:start position:0% +go through uh the explanation of how we +get + + align:start position:0% +get + + + align:start position:0% +get +those okay so we're writing them in ter + + align:start position:0% +those okay so we're writing them in ter + + + align:start position:0% +those okay so we're writing them in ter +in terms of order statistics okay and + + align:start position:0% +in terms of order statistics okay and + + + align:start position:0% +in terms of order statistics okay and +let me just point out that actually once + + align:start position:0% +let me just point out that actually once + + + align:start position:0% +let me just point out that actually once +once I convince you that these bounds + + align:start position:0% +once I convince you that these bounds + + + align:start position:0% +once I convince you that these bounds +are correct which I hope to do in just a + + align:start position:0% +are correct which I hope to do in just a + + + align:start position:0% +are correct which I hope to do in just a +moment then the maximum likelihood + + align:start position:0% +moment then the maximum likelihood + + + align:start position:0% +moment then the maximum likelihood +estimator is going to be any value in + + align:start position:0% +estimator is going to be any value in + + + align:start position:0% +estimator is going to be any value in +that uh interval because any value in + + align:start position:0% +that uh interval because any value in + + + align:start position:0% +that uh interval because any value in +this interval maximizes the likelihood + + align:start position:0% +this interval maximizes the likelihood + + + align:start position:0% +this interval maximizes the likelihood +function okay it's just flat over that + + align:start position:0% +function okay it's just flat over that + + + align:start position:0% +function okay it's just flat over that +interval it's equal to one so any value + + align:start position:0% +interval it's equal to one so any value + + + align:start position:0% +interval it's equal to one so any value +in that interval is going to maximize + + align:start position:0% +in that interval is going to maximize + + + align:start position:0% +in that interval is going to maximize +the likelihood + + align:start position:0% +the likelihood + + + align:start position:0% +the likelihood +function okay so now I just have to + + align:start position:0% +function okay so now I just have to + + + align:start position:0% +function okay so now I just have to +convince you that these uh that this + + align:start position:0% +convince you that these uh that this + + + align:start position:0% +convince you that these uh that this +sort of condition is + + align:start position:0% +sort of condition is + + + align:start position:0% +sort of condition is +correct okay so let's look at this one + + align:start position:0% +correct okay so let's look at this one + + + align:start position:0% +correct okay so let's look at this one +graphically so let's suppose we've got a + + align:start position:0% +graphically so let's suppose we've got a + + + align:start position:0% +graphically so let's suppose we've got a +random + + align:start position:0% +random + + + align:start position:0% +random +sample the interval that the the + + align:start position:0% +sample the interval that the the + + + align:start position:0% +sample the interval that the the +underlying distribution is has you know + + align:start position:0% +underlying distribution is has you know + + + align:start position:0% +underlying distribution is has you know +a uniform where the interval is length + + align:start position:0% +a uniform where the interval is length + + + align:start position:0% +a uniform where the interval is length +one and it's centered at Theta and it's + + align:start position:0% +one and it's centered at Theta and it's + + + align:start position:0% +one and it's centered at Theta and it's +got to be here somewhere okay this is + + align:start position:0% +got to be here somewhere okay this is + + + align:start position:0% +got to be here somewhere okay this is +our random sample so it's got to sort of + + align:start position:0% +our random sample so it's got to sort of + + + align:start position:0% +our random sample so it's got to sort of +all of these uh observations have to + + align:start position:0% +all of these uh observations have to + + + align:start position:0% +all of these uh observations have to +live in that interval okay it's got to + + align:start position:0% +live in that interval okay it's got to + + + align:start position:0% +live in that interval okay it's got to +Encompass all the data so what are the + + align:start position:0% +Encompass all the data so what are the + + + align:start position:0% +Encompass all the data so what are the +possibilities well the interval could be + + align:start position:0% +possibilities well the interval could be + + + align:start position:0% +possibilities well the interval could be +there could be there could be there + + align:start position:0% +there could be there could be there + + + align:start position:0% +there could be there could be there +could be + + align:start position:0% +could be + + + align:start position:0% +could be +there and in fact all there's a whole + + align:start position:0% +there and in fact all there's a whole + + + align:start position:0% +there and in fact all there's a whole +Continuum right and all of those + + align:start position:0% +Continuum right and all of those + + + align:start position:0% +Continuum right and all of those +possibilities are equally + + align:start position:0% +possibilities are equally + + + align:start position:0% +possibilities are equally +likely + + align:start position:0% +likely + + + align:start position:0% +likely +okay can it be there no no way right + + align:start position:0% +okay can it be there no no way right + + + align:start position:0% +okay can it be there no no way right +because if it's if it's over here then + + align:start position:0% +because if it's if it's over here then + + + align:start position:0% +because if it's if it's over here then +these these happen these occurred with + + align:start position:0% +these these happen these occurred with + + + align:start position:0% +these these happen these occurred with +probability zero or they couldn't they + + align:start position:0% +probability zero or they couldn't they + + + align:start position:0% +probability zero or they couldn't they +couldn't occur + + align:start position:0% +couldn't occur + + + align:start position:0% +couldn't occur +okay likewise can't be there okay so I + + align:start position:0% +okay likewise can't be there okay so I + + + align:start position:0% +okay likewise can't be there okay so I +think I've convinced you that there's + + align:start position:0% +think I've convinced you that there's + + + align:start position:0% +think I've convinced you that there's +sort of a range of different + + align:start position:0% +sort of a range of different + + + align:start position:0% +sort of a range of different +possibilities that for the location of + + align:start position:0% +possibilities that for the location of + + + align:start position:0% +possibilities that for the location of +this interval of length one and the only + + align:start position:0% +this interval of length one and the only + + + align:start position:0% +this interval of length one and the only +question is how do we um how do we + + align:start position:0% +question is how do we um how do we + + + align:start position:0% +question is how do we um how do we +express what that range is okay + + align:start position:0% +express what that range is okay + + + align:start position:0% +express what that range is okay +well the Theta can be at most 1/2 above + + align:start position:0% +well the Theta can be at most 1/2 above + + + align:start position:0% +well the Theta can be at most 1/2 above +the first order + + align:start position:0% +the first order + + + align:start position:0% +the first order +statistic okay let me just flip back so + + align:start position:0% +statistic okay let me just flip back so + + + align:start position:0% +statistic okay let me just flip back so +over here is the first order statistic + + align:start position:0% +over here is the first order statistic + + + align:start position:0% +over here is the first order statistic +okay we know that the the left edge of + + align:start position:0% +okay we know that the the left edge of + + + align:start position:0% +okay we know that the the left edge of +the interval can't be any higher than + + align:start position:0% +the interval can't be any higher than + + + align:start position:0% +the interval can't be any higher than +the first order statistic so therefore + + align:start position:0% +the first order statistic so therefore + + + align:start position:0% +the first order statistic so therefore +Theta can't be any higher than 1/2 above + + align:start position:0% +Theta can't be any higher than 1/2 above + + + align:start position:0% +Theta can't be any higher than 1/2 above +that okay then the same reasoning goes + + align:start position:0% +that okay then the same reasoning goes + + + align:start position:0% +that okay then the same reasoning goes +with the nth order statistic + + align:start position:0% +with the nth order statistic + + + align:start position:0% +with the nth order statistic +oops Theta can be at most 1/ half below + + align:start position:0% +oops Theta can be at most 1/ half below + + + align:start position:0% +oops Theta can be at most 1/ half below +the enth order statistic it can't be any + + align:start position:0% +the enth order statistic it can't be any + + + align:start position:0% +the enth order statistic it can't be any +further down or we're going to start + + align:start position:0% +further down or we're going to start + + + align:start position:0% +further down or we're going to start +missing the observations at the top + + align:start position:0% +missing the observations at the top + + + align:start position:0% +missing the observations at the top +okay and so that gives us a you know + + align:start position:0% +okay and so that gives us a you know + + + align:start position:0% +okay and so that gives us a you know +sort of a a little region in which Theta + + align:start position:0% +sort of a a little region in which Theta + + + align:start position:0% +sort of a a little region in which Theta +can live and all the values in Theta in + + align:start position:0% +can live and all the values in Theta in + + + align:start position:0% +can live and all the values in Theta in +that little region in that window are + + align:start position:0% +that little region in that window are + + + align:start position:0% +that little region in that window are +equally likely because we wrote down the + + align:start position:0% +equally likely because we wrote down the + + + align:start position:0% +equally likely because we wrote down the +likelihood functions it's just equal to + + align:start position:0% +likelihood functions it's just equal to + + + align:start position:0% +likelihood functions it's just equal to +one in that region okay so in fact if + + align:start position:0% +one in that region okay so in fact if + + + align:start position:0% +one in that region okay so in fact if +you you know + + align:start position:0% +you you know + + + align:start position:0% +you you know +I can flip back if you want but this is + + align:start position:0% +I can flip back if you want but this is + + + align:start position:0% +I can flip back if you want but this is +in fact uh the the condition that I had + + align:start position:0% +in fact uh the the condition that I had + + + align:start position:0% +in fact uh the the condition that I had +on the likelihood function okay so let + + align:start position:0% +on the likelihood function okay so let + + + align:start position:0% +on the likelihood function okay so let +me just okay that Theta is in the nth + + align:start position:0% +me just okay that Theta is in the nth + + + align:start position:0% +me just okay that Theta is in the nth +order statistic minus + + align:start position:0% +order statistic minus + + + align:start position:0% +order statistic minus +one2 a to up to the first order + + align:start position:0% +one2 a to up to the first order + + + align:start position:0% +one2 a to up to the first order +statistic plus 1/2 there should be sort + + align:start position:0% +statistic plus 1/2 there should be sort + + + align:start position:0% +statistic plus 1/2 there should be sort +of an overlap and that the overlap of + + align:start position:0% +of an overlap and that the overlap of + + + align:start position:0% +of an overlap and that the overlap of +those two um you know sort of conditions + + align:start position:0% +those two um you know sort of conditions + + + align:start position:0% +those two um you know sort of conditions +uh gives us the region where Theta + + align:start position:0% +uh gives us the region where Theta + + + align:start position:0% +uh gives us the region where Theta +live does that make + + align:start position:0% + + + + align:start position:0% + +sense yes + + align:start position:0% +sense yes + + + align:start position:0% +sense yes +okay okay so maximum likelihood + + align:start position:0% +okay okay so maximum likelihood + + + align:start position:0% +okay okay so maximum likelihood +estimators are you know it's sort of + + align:start position:0% +estimators are you know it's sort of + + + align:start position:0% +estimators are you know it's sort of +it's a very popular framework for uh + + align:start position:0% +it's a very popular framework for uh + + + align:start position:0% +it's a very popular framework for uh +deriving + + align:start position:0% +deriving + + + align:start position:0% +deriving +estimators and they and part of it is + + align:start position:0% +estimators and they and part of it is + + + align:start position:0% +estimators and they and part of it is +because they have some very favorable + + align:start position:0% +because they have some very favorable + + + align:start position:0% +because they have some very favorable +properties well part of it is because + + align:start position:0% +properties well part of it is because + + + align:start position:0% +properties well part of it is because +they're kind of always available if + + align:start position:0% +they're kind of always available if + + + align:start position:0% +they're kind of always available if +you're willing to take a stand like make + + align:start position:0% +you're willing to take a stand like make + + + align:start position:0% +you're willing to take a stand like make +an assumption about what the underlying + + align:start position:0% +an assumption about what the underlying + + + align:start position:0% +an assumption about what the underlying +distribution is then you can write down + + align:start position:0% +distribution is then you can write down + + + align:start position:0% +distribution is then you can write down +a maximum likelihood estimator okay of + + align:start position:0% +a maximum likelihood estimator okay of + + + align:start position:0% +a maximum likelihood estimator okay of +course that's also true for a method of + + align:start position:0% +course that's also true for a method of + + + align:start position:0% +course that's also true for a method of +moments estimator but uh you know sort + + align:start position:0% +moments estimator but uh you know sort + + + align:start position:0% +moments estimator but uh you know sort +of Maximum likelihood estimators are you + + align:start position:0% +of Maximum likelihood estimators are you + + + align:start position:0% +of Maximum likelihood estimators are you +know sort of available uh you know if + + align:start position:0% +know sort of available uh you know if + + + align:start position:0% +know sort of available uh you know if +you're sort of willing to write down a a + + align:start position:0% +you're sort of willing to write down a a + + + align:start position:0% +you're sort of willing to write down a a +distribution of the underlying um + + align:start position:0% +distribution of the underlying um + + + align:start position:0% +distribution of the underlying um +data but it they also have some very + + align:start position:0% +data but it they also have some very + + + align:start position:0% +data but it they also have some very +favorable properties so if your + + align:start position:0% +favorable properties so if your + + + align:start position:0% +favorable properties so if your +assumptions are correct so this is all + + align:start position:0% +assumptions are correct so this is all + + + align:start position:0% +assumptions are correct so this is all +assuming that you haven't made a mistake + + align:start position:0% +assuming that you haven't made a mistake + + + align:start position:0% +assuming that you haven't made a mistake +in sort of assuming the underlying + + align:start position:0% +in sort of assuming the underlying + + + align:start position:0% +in sort of assuming the underlying +distribution then the maximum likelihood + + align:start position:0% +distribution then the maximum likelihood + + + align:start position:0% +distribution then the maximum likelihood +estimator is going to have the following + + align:start position:0% +estimator is going to have the following + + + align:start position:0% +estimator is going to have the following +properties if there is an efficient + + align:start position:0% +properties if there is an efficient + + + align:start position:0% +properties if there is an efficient +estimator in a class of consistent + + align:start position:0% +estimator in a class of consistent + + + align:start position:0% +estimator in a class of consistent +estimators maximum likelihood estimation + + align:start position:0% +estimators maximum likelihood estimation + + + align:start position:0% +estimators maximum likelihood estimation +will produce it okay so that tells you + + align:start position:0% +will produce it okay so that tells you + + + align:start position:0% +will produce it okay so that tells you +right there you don't have to check for + + align:start position:0% +right there you don't have to check for + + + align:start position:0% +right there you don't have to check for +the efficiency of your estimator um if + + align:start position:0% +the efficiency of your estimator um if + + + align:start position:0% +the efficiency of your estimator um if +you're using maximum likelihood you know + + align:start position:0% +you're using maximum likelihood you know + + + align:start position:0% +you're using maximum likelihood you know +it's it's going to have it's going to + + align:start position:0% +it's it's going to have it's going to + + + align:start position:0% +it's it's going to have it's going to +have that a good property in that + + align:start position:0% +have that a good property in that + + + align:start position:0% +have that a good property in that +respect + + align:start position:0% +respect + + + align:start position:0% +respect +okay + + align:start position:0% +okay + + + align:start position:0% +okay +um also there is a central limit theorem + + align:start position:0% +um also there is a central limit theorem + + + align:start position:0% +um also there is a central limit theorem +type um result having to do with a + + align:start position:0% +type um result having to do with a + + + align:start position:0% +type um result having to do with a +maximum likelihood estimators so under + + align:start position:0% +maximum likelihood estimators so under + + + align:start position:0% +maximum likelihood estimators so under +certain regularity conditions if uh you + + align:start position:0% +certain regularity conditions if uh you + + + align:start position:0% +certain regularity conditions if uh you +know sort of the maximum likelihood + + align:start position:0% +know sort of the maximum likelihood + + + align:start position:0% +know sort of the maximum likelihood +estimator is not on some boundary of + + align:start position:0% +estimator is not on some boundary of + + + align:start position:0% +estimator is not on some boundary of +some space or something like that then + + align:start position:0% +some space or something like that then + + + align:start position:0% +some space or something like that then +uh asymptotically sort of as your um + + align:start position:0% +uh asymptotically sort of as your um + + + align:start position:0% +uh asymptotically sort of as your um +sample size is getting bigger and bigger + + align:start position:0% +sample size is getting bigger and bigger + + + align:start position:0% +sample size is getting bigger and bigger +maximum likelihood estimators are going + + align:start position:0% +maximum likelihood estimators are going + + + align:start position:0% +maximum likelihood estimators are going +to have a normal or approximately normal + + align:start position:0% +to have a normal or approximately normal + + + align:start position:0% +to have a normal or approximately normal +distribution so just like we had the + + align:start position:0% +distribution so just like we had the + + + align:start position:0% +distribution so just like we had the +central limit theorem for the sample + + align:start position:0% +central limit theorem for the sample + + + align:start position:0% +central limit theorem for the sample +mean there's a central limit theorem + + align:start position:0% +mean there's a central limit theorem + + + align:start position:0% +mean there's a central limit theorem +like result for maximum likelihood + + align:start position:0% +like result for maximum likelihood + + + align:start position:0% +like result for maximum likelihood +estimators and that's uh that can be + + align:start position:0% +estimators and that's uh that can be + + + align:start position:0% +estimators and that's uh that can be +very uh useful for inference which we'll + + align:start position:0% +very uh useful for inference which we'll + + + align:start position:0% +very uh useful for inference which we'll +see after spring + + align:start position:0% + + + + align:start position:0% + +break so does this mean that uh maximum + + align:start position:0% +break so does this mean that uh maximum + + + align:start position:0% +break so does this mean that uh maximum +likelihood estimation is always the + + align:start position:0% +likelihood estimation is always the + + + align:start position:0% +likelihood estimation is always the +right thing to do okay well well uh no + + align:start position:0% +right thing to do okay well well uh no + + + align:start position:0% +right thing to do okay well well uh no +in fact + + align:start position:0% +in fact + + + align:start position:0% +in fact +so in we saw an example where uh where + + align:start position:0% +so in we saw an example where uh where + + + align:start position:0% +so in we saw an example where uh where +you know even given that our you know + + align:start position:0% +you know even given that our you know + + + align:start position:0% +you know even given that our you know +our assumptions were correct the maximum + + align:start position:0% +our assumptions were correct the maximum + + + align:start position:0% +our assumptions were correct the maximum +likelihood estimator was biased okay so + + align:start position:0% +likelihood estimator was biased okay so + + + align:start position:0% +likelihood estimator was biased okay so +that was the example where we were + + align:start position:0% +that was the example where we were + + + align:start position:0% +that was the example where we were +estimating Theta from the uniform zero + + align:start position:0% +estimating Theta from the uniform zero + + + align:start position:0% +estimating Theta from the uniform zero +Theta distribution um and our maximum + + align:start position:0% +Theta distribution um and our maximum + + + align:start position:0% +Theta distribution um and our maximum +likelihood uh estimator for any finite + + align:start position:0% +likelihood uh estimator for any finite + + + align:start position:0% +likelihood uh estimator for any finite +sample size was going to be biased okay + + align:start position:0% +sample size was going to be biased okay + + + align:start position:0% +sample size was going to be biased okay +now in fact in that particular example + + align:start position:0% +now in fact in that particular example + + + align:start position:0% +now in fact in that particular example +we could fix the bias because the bias + + align:start position:0% +we could fix the bias because the bias + + + align:start position:0% +we could fix the bias because the bias +is a function of N and we know how big + + align:start position:0% +is a function of N and we know how big + + + align:start position:0% +is a function of N and we know how big +our sample size is so we can actually + + align:start position:0% +our sample size is so we can actually + + + align:start position:0% +our sample size is so we can actually +undo that bias um but in in there are + + align:start position:0% +undo that bias um but in in there are + + + align:start position:0% +undo that bias um but in in there are +lots of examples where you don't know + + align:start position:0% +lots of examples where you don't know + + + align:start position:0% +lots of examples where you don't know +the size of the bias and so you can't + + align:start position:0% +the size of the bias and so you can't + + + align:start position:0% +the size of the bias and so you can't +always undo it okay so they can be + + align:start position:0% +always undo it okay so they can be + + + align:start position:0% +always undo it okay so they can be +biased and we saw an example and + + align:start position:0% +biased and we saw an example and + + + align:start position:0% +biased and we saw an example and +sometimes we just you know we're we're + + align:start position:0% +sometimes we just you know we're we're + + + align:start position:0% +sometimes we just you know we're we're +not interested in biased + + align:start position:0% +not interested in biased + + + align:start position:0% +not interested in biased +estimators they might be difficult to + + align:start position:0% +estimators they might be difficult to + + + align:start position:0% +estimators they might be difficult to +compute and then um finally they can be + + align:start position:0% +compute and then um finally they can be + + + align:start position:0% +compute and then um finally they can be +sensitive to incorrect assumptions about + + align:start position:0% +sensitive to incorrect assumptions about + + + align:start position:0% +sensitive to incorrect assumptions about +the underlying distribution so um and + + align:start position:0% +the underlying distribution so um and + + + align:start position:0% +the underlying distribution so um and +more so than other estimators so the the + + align:start position:0% +more so than other estimators so the the + + + align:start position:0% +more so than other estimators so the the +method of moments uh estimators tend to + + align:start position:0% +method of moments uh estimators tend to + + + align:start position:0% +method of moments uh estimators tend to +be more robust to uh sort of um the + + align:start position:0% +be more robust to uh sort of um the + + + align:start position:0% +be more robust to uh sort of um the +underlying assumptions because they rely + + align:start position:0% +underlying assumptions because they rely + + + align:start position:0% +underlying assumptions because they rely +less so the maximum likelihood + + align:start position:0% +less so the maximum likelihood + + + align:start position:0% +less so the maximum likelihood +estimators really rely on the entire + + align:start position:0% +estimators really rely on the entire + + + align:start position:0% +estimators really rely on the entire +shape of the distribution of the random + + align:start position:0% +shape of the distribution of the random + + + align:start position:0% +shape of the distribution of the random +sample Le the method of moments + + align:start position:0% +sample Le the method of moments + + + align:start position:0% +sample Le the method of moments +estimators don't they just rely on the + + align:start position:0% +estimators don't they just rely on the + + + align:start position:0% +estimators don't they just rely on the +moments and so you can imagine just kind + + align:start position:0% +moments and so you can imagine just kind + + + align:start position:0% +moments and so you can imagine just kind +of intuitively that something that + + align:start position:0% +of intuitively that something that + + + align:start position:0% +of intuitively that something that +relies on the entire shape of a + + align:start position:0% +relies on the entire shape of a + + + align:start position:0% +relies on the entire shape of a +distribution if you're if you're wrong + + align:start position:0% +distribution if you're if you're wrong + + + align:start position:0% +distribution if you're if you're wrong +about that shape of a distribution you + + align:start position:0% +about that shape of a distribution you + + + align:start position:0% +about that shape of a distribution you +know it might be sensitive that + + align:start position:0% +know it might be sensitive that + + + align:start position:0% +know it might be sensitive that +something can go wrong and that's in + + align:start position:0% +something can go wrong and that's in + + + align:start position:0% +something can go wrong and that's in +general true maximum likelihood + + align:start position:0% +general true maximum likelihood + + + align:start position:0% +general true maximum likelihood +estimators can be sensitive to incorrect + + align:start position:0% +estimators can be sensitive to incorrect + + + align:start position:0% +estimators can be sensitive to incorrect +assumptions about the underlying + + align:start position:0% +assumptions about the underlying + + + align:start position:0% +assumptions about the underlying +distributions okay questions + + align:start position:0% + + + + align:start position:0% + +no okay so I would like to just go + + align:start position:0% +no okay so I would like to just go + + + align:start position:0% +no okay so I would like to just go +through um a a summary of what we've + + align:start position:0% +through um a a summary of what we've + + + align:start position:0% +through um a a summary of what we've +done so far this semester and uh feel + + align:start position:0% +done so far this semester and uh feel + + + align:start position:0% +done so far this semester and uh feel +free to chime in with questions um + + align:start position:0% +free to chime in with questions um + + + align:start position:0% +free to chime in with questions um +and you know ask about if you have + + align:start position:0% +and you know ask about if you have + + + align:start position:0% +and you know ask about if you have +questions about the exam you know sort + + align:start position:0% +questions about the exam you know sort + + + align:start position:0% +questions about the exam you know sort +of relative to this you know what you + + align:start position:0% +of relative to this you know what you + + + align:start position:0% +of relative to this you know what you +might be responsible for on the exam I'm + + align:start position:0% +might be responsible for on the exam I'm + + + align:start position:0% +might be responsible for on the exam I'm +happy to answer those questions + + align:start position:0% +happy to answer those questions + + + align:start position:0% +happy to answer those questions +okay so we started out uh this semester + + align:start position:0% +okay so we started out uh this semester + + + align:start position:0% +okay so we started out uh this semester +with uh some probability Basics okay so + + align:start position:0% +with uh some probability Basics okay so + + + align:start position:0% +with uh some probability Basics okay so +uh we introduced the concept of + + align:start position:0% +uh we introduced the concept of + + + align:start position:0% +uh we introduced the concept of +probability and talked about simple + + align:start position:0% +probability and talked about simple + + + align:start position:0% +probability and talked about simple +sample spaces independent events + + align:start position:0% +sample spaces independent events + + + align:start position:0% +sample spaces independent events +conditional probabilities and base + + align:start position:0% + + + + align:start position:0% + +Rule and in some sense that was kind + + align:start position:0% +Rule and in some sense that was kind + + + align:start position:0% +Rule and in some sense that was kind +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +of foundation for uh you know sort of + + align:start position:0% +of foundation for uh you know sort of + + + align:start position:0% +of foundation for uh you know sort of +going on and and studying probability + + align:start position:0% +going on and and studying probability + + + align:start position:0% +going on and and studying probability +with the kind of mathematical construct + + align:start position:0% +with the kind of mathematical construct + + + align:start position:0% +with the kind of mathematical construct +of the the random variable but do note + + align:start position:0% +of the the random variable but do note + + + align:start position:0% +of the the random variable but do note +that uh we didn't study the sort of uh + + align:start position:0% +that uh we didn't study the sort of uh + + + align:start position:0% +that uh we didn't study the sort of uh +we didn't study base rule in the context + + align:start position:0% +we didn't study base rule in the context + + + align:start position:0% +we didn't study base rule in the context +of um random variables you can you can + + align:start position:0% +of um random variables you can you can + + + align:start position:0% +of um random variables you can you can +actually um sort of formulate a Baye + + align:start position:0% +actually um sort of formulate a Baye + + + align:start position:0% +actually um sort of formulate a Baye +rule using random variables which we + + align:start position:0% +rule using random variables which we + + + align:start position:0% +rule using random variables which we +didn't do uh but it's sort of a Bas Ru + + align:start position:0% +didn't do uh but it's sort of a Bas Ru + + + align:start position:0% +didn't do uh but it's sort of a Bas Ru +is a very important concept um that you + + align:start position:0% +is a very important concept um that you + + + align:start position:0% +is a very important concept um that you +know sort of aside from uh you know Pro + + align:start position:0% +know sort of aside from uh you know Pro + + + align:start position:0% +know sort of aside from uh you know Pro +I guess sort of the the one concept that + + align:start position:0% +I guess sort of the the one concept that + + + align:start position:0% +I guess sort of the the one concept that +we covered in the beginning that wasn't + + align:start position:0% +we covered in the beginning that wasn't + + + align:start position:0% +we covered in the beginning that wasn't +sort of just foundation for the rest of + + align:start position:0% +sort of just foundation for the rest of + + + align:start position:0% +sort of just foundation for the rest of +what we're doing + + align:start position:0% +what we're doing + + + align:start position:0% +what we're doing +okay then we introduced uh random + + align:start position:0% +okay then we introduced uh random + + + align:start position:0% +okay then we introduced uh random +variables and uh we defined what a + + align:start position:0% +variables and uh we defined what a + + + align:start position:0% +variables and uh we defined what a +random variable was we discussed ways to + + align:start position:0% +random variable was we discussed ways to + + + align:start position:0% +random variable was we discussed ways to +represent distribution so a probability + + align:start position:0% +represent distribution so a probability + + + align:start position:0% +represent distribution so a probability +function a probability density function + + align:start position:0% +function a probability density function + + + align:start position:0% +function a probability density function +so those were kind of + + align:start position:0% +so those were kind of + + + align:start position:0% +so those were kind of +analogous uh sort of things but one was + + align:start position:0% +analogous uh sort of things but one was + + + align:start position:0% +analogous uh sort of things but one was +for discrete random variables and one + + align:start position:0% +for discrete random variables and one + + + align:start position:0% +for discrete random variables and one +was for continuous random variables and + + align:start position:0% +was for continuous random variables and + + + align:start position:0% +was for continuous random variables and +then we also talked about how the same + + align:start position:0% +then we also talked about how the same + + + align:start position:0% +then we also talked about how the same +information in PFS and PDFs can be + + align:start position:0% +information in PFS and PDFs can be + + + align:start position:0% +information in PFS and PDFs can be +embodied in a CDF okay and that's the + + align:start position:0% +embodied in a CDF okay and that's the + + + align:start position:0% +embodied in a CDF okay and that's the +definition of a CDF is the same for both + + align:start position:0% +definition of a CDF is the same for both + + + align:start position:0% +definition of a CDF is the same for both +uh continuous and discrete random + + align:start position:0% +uh continuous and discrete random + + + align:start position:0% +uh continuous and discrete random +variables and um then we also covered + + align:start position:0% +variables and um then we also covered + + + align:start position:0% +variables and um then we also covered +sort of the random variable analogues to + + align:start position:0% +sort of the random variable analogues to + + + align:start position:0% +sort of the random variable analogues to +the sort of stuff we covered in + + align:start position:0% +the sort of stuff we covered in + + + align:start position:0% +the sort of stuff we covered in +probability Basics so we talked about we + + align:start position:0% +probability Basics so we talked about we + + + align:start position:0% +probability Basics so we talked about we +had talked about independent events then + + align:start position:0% +had talked about independent events then + + + align:start position:0% +had talked about independent events then +we talked about independent random + + align:start position:0% +we talked about independent random + + + align:start position:0% +we talked about independent random +variables we talked about conditional + + align:start position:0% +variables we talked about conditional + + + align:start position:0% +variables we talked about conditional +probabilities then talked about + + align:start position:0% +probabilities then talked about + + + align:start position:0% +probabilities then talked about +conditional PDFs + + align:start position:0% +conditional PDFs + + + align:start position:0% +conditional PDFs +okay and then uh then Esther uh covered + + align:start position:0% +okay and then uh then Esther uh covered + + + align:start position:0% +okay and then uh then Esther uh covered +some um sort of um I don't know + + align:start position:0% +some um sort of um I don't know + + + align:start position:0% +some um sort of um I don't know +empirical counterparts to some of the + + align:start position:0% +empirical counterparts to some of the + + + align:start position:0% +empirical counterparts to some of the +things that we had been talking about + + align:start position:0% +things that we had been talking about + + + align:start position:0% +things that we had been talking about +theoretically in class so she talked + + align:start position:0% +theoretically in class so she talked + + + align:start position:0% +theoretically in class so she talked +about both a histogram defined what a + + align:start position:0% +about both a histogram defined what a + + + align:start position:0% +about both a histogram defined what a +histogram was showed us some nice + + align:start position:0% +histogram was showed us some nice + + + align:start position:0% +histogram was showed us some nice +examples and then also talked about um + + align:start position:0% +examples and then also talked about um + + + align:start position:0% +examples and then also talked about um +uh kernel density estimate and sort of + + align:start position:0% +uh kernel density estimate and sort of + + + align:start position:0% +uh kernel density estimate and sort of +what the difference between a histogram + + align:start position:0% +what the difference between a histogram + + + align:start position:0% +what the difference between a histogram +and a kernel density estimate is um and + + align:start position:0% +and a kernel density estimate is um and + + + align:start position:0% +and a kernel density estimate is um and +showed us some pictures of those as + + align:start position:0% +showed us some pictures of those as + + + align:start position:0% +showed us some pictures of those as +well and uh sort of uh you know we saw + + align:start position:0% +well and uh sort of uh you know we saw + + + align:start position:0% +well and uh sort of uh you know we saw +lots of examples that we hope gave you + + align:start position:0% +lots of examples that we hope gave you + + + align:start position:0% +lots of examples that we hope gave you +kind of a sense for how these + + align:start position:0% +kind of a sense for how these + + + align:start position:0% +kind of a sense for how these +theoretical you know objects function + + align:start position:0% +theoretical you know objects function + + + align:start position:0% +theoretical you know objects function +and what information they tell us and + + align:start position:0% +and what information they tell us and + + + align:start position:0% +and what information they tell us and +how to interpret them um then we started + + align:start position:0% +how to interpret them um then we started + + + align:start position:0% +how to interpret them um then we started +talking about functions of random + + align:start position:0% +talking about functions of random + + + align:start position:0% +talking about functions of random +variables so we saw some basic + + align:start position:0% +variables so we saw some basic + + + align:start position:0% +variables so we saw some basic +strategies or I guess actually one basic + + align:start position:0% +strategies or I guess actually one basic + + + align:start position:0% +strategies or I guess actually one basic +strategy for figuring out the + + align:start position:0% +strategy for figuring out the + + + align:start position:0% +strategy for figuring out the +distribution of a function of random + + align:start position:0% +distribution of a function of random + + + align:start position:0% +distribution of a function of random +variables and then I also did I went + + align:start position:0% +variables and then I also did I went + + + align:start position:0% +variables and then I also did I went +through several important examples and + + align:start position:0% +through several important examples and + + + align:start position:0% +through several important examples and +um so I think it it's useful to go back + + align:start position:0% +um so I think it it's useful to go back + + + align:start position:0% +um so I think it it's useful to go back +and sort of be comfortable with the + + align:start position:0% +and sort of be comfortable with the + + + align:start position:0% +and sort of be comfortable with the +examples so what were some of the + + align:start position:0% +examples so what were some of the + + + align:start position:0% +examples so what were some of the +examples that we went through well we + + align:start position:0% +examples that we went through well we + + + align:start position:0% +examples that we went through well we +did a sort of the um probability + + align:start position:0% +did a sort of the um probability + + + align:start position:0% +did a sort of the um probability +integral + + align:start position:0% +integral + + + align:start position:0% +integral +transformation and we did uh convolution + + align:start position:0% +transformation and we did uh convolution + + + align:start position:0% +transformation and we did uh convolution +we did linear transformations of Rand + + align:start position:0% +we did linear transformations of Rand + + + align:start position:0% +we did linear transformations of Rand +variables we did order + + align:start position:0% +variables we did order + + + align:start position:0% +variables we did order +statistics maybe that's it I'm not sure + + align:start position:0% +statistics maybe that's it I'm not sure + + + align:start position:0% +statistics maybe that's it I'm not sure +maybe there's one more I don't know + + align:start position:0% +maybe there's one more I don't know + + + align:start position:0% +maybe there's one more I don't know +those are sort of uh those are all + + align:start position:0% +those are sort of uh those are all + + + align:start position:0% +those are sort of uh those are all +important examples and all things that + + align:start position:0% +important examples and all things that + + + align:start position:0% +important examples and all things that +we sort of have drawn on since and we'll + + align:start position:0% +we sort of have drawn on since and we'll + + + align:start position:0% +we sort of have drawn on since and we'll +continue to draw + + align:start position:0% + + + + align:start position:0% + +on then we sort of introduced uh moments + + align:start position:0% +on then we sort of introduced uh moments + + + align:start position:0% +on then we sort of introduced uh moments +of distributions so we defined uh mean + + align:start position:0% +of distributions so we defined uh mean + + + align:start position:0% +of distributions so we defined uh mean +variance we defined a few couple other + + align:start position:0% +variance we defined a few couple other + + + align:start position:0% +variance we defined a few couple other +uh but we mostly focused on the mean and + + align:start position:0% +uh but we mostly focused on the mean and + + + align:start position:0% +uh but we mostly focused on the mean and +variance and then in addition to + + align:start position:0% +variance and then in addition to + + + align:start position:0% +variance and then in addition to +learning how to or expectation if you'd + + align:start position:0% +learning how to or expectation if you'd + + + align:start position:0% +learning how to or expectation if you'd +rather expectation and variance in + + align:start position:0% +rather expectation and variance in + + + align:start position:0% +rather expectation and variance in +addition to sort of learning how to + + align:start position:0% +addition to sort of learning how to + + + align:start position:0% +addition to sort of learning how to +directly compute the expectation and + + align:start position:0% +directly compute the expectation and + + + align:start position:0% +directly compute the expectation and +variance uh given the distribution of a + + align:start position:0% +variance uh given the distribution of a + + + align:start position:0% +variance uh given the distribution of a +random variable we also learned a lot of + + align:start position:0% +random variable we also learned a lot of + + + align:start position:0% +random variable we also learned a lot of +techniques and properties to help + + align:start position:0% +techniques and properties to help + + + align:start position:0% +techniques and properties to help +compute moments of functions of random + + align:start position:0% +compute moments of functions of random + + + align:start position:0% +compute moments of functions of random +variables so you have uh you have a + + align:start position:0% +variables so you have uh you have a + + + align:start position:0% +variables so you have uh you have a +random variable maybe you know its + + align:start position:0% +random variable maybe you know its + + + align:start position:0% +random variable maybe you know its +moments + + align:start position:0% +moments + + + align:start position:0% +moments +uh but what you're really concerned with + + align:start position:0% +uh but what you're really concerned with + + + align:start position:0% +uh but what you're really concerned with +is a function of that random variable do + + align:start position:0% +is a function of that random variable do + + + align:start position:0% +is a function of that random variable do +you have to figure out how that function + + align:start position:0% +you have to figure out how that function + + + align:start position:0% +you have to figure out how that function +is distributed and then compute the + + align:start position:0% +is distributed and then compute the + + + align:start position:0% +is distributed and then compute the +moments directly you can do that usually + + align:start position:0% +moments directly you can do that usually + + + align:start position:0% +moments directly you can do that usually +you don't often times we can just uh + + align:start position:0% +you don't often times we can just uh + + + align:start position:0% +you don't often times we can just uh +rely on like properties of expectation + + align:start position:0% +rely on like properties of expectation + + + align:start position:0% +rely on like properties of expectation +properties of variance properties of + + align:start position:0% +properties of variance properties of + + + align:start position:0% +properties of variance properties of +co-variance Etc um to figure out the the + + align:start position:0% +co-variance Etc um to figure out the the + + + align:start position:0% +co-variance Etc um to figure out the the +characteristics of distributions of + + align:start position:0% +characteristics of distributions of + + + align:start position:0% +characteristics of distributions of +functions of Random variabl + + align:start position:0% +functions of Random variabl + + + align:start position:0% +functions of Random variabl +okay then uh Esther went through uh a + + align:start position:0% +okay then uh Esther went through uh a + + + align:start position:0% +okay then uh Esther went through uh a +whole lecture discussing special + + align:start position:0% +whole lecture discussing special + + + align:start position:0% +whole lecture discussing special +distributions and uh these are all + + align:start position:0% +distributions and uh these are all + + + align:start position:0% +distributions and uh these are all +distributions that are useful they + + align:start position:0% +distributions that are useful they + + + align:start position:0% +distributions that are useful they +distributions that will re-enter your + + align:start position:0% +distributions that will re-enter your + + + align:start position:0% +distributions that will re-enter your +life at some point in high probability I + + align:start position:0% +life at some point in high probability I + + + align:start position:0% +life at some point in high probability I +would say um they uh they distributions + + align:start position:0% +would say um they uh they distributions + + + align:start position:0% +would say um they uh they distributions +that we will continue to discuss + + align:start position:0% +that we will continue to discuss + + + align:start position:0% +that we will continue to discuss +throughout the semester and so it's good + + align:start position:0% +throughout the semester and so it's good + + + align:start position:0% +throughout the semester and so it's good +if you sort of have some level of + + align:start position:0% +if you sort of have some level of + + + align:start position:0% +if you sort of have some level of +comfort with them we're not interested + + align:start position:0% +comfort with them we're not interested + + + align:start position:0% +comfort with them we're not interested +in having you memorize PDFs of special + + align:start position:0% +in having you memorize PDFs of special + + + align:start position:0% +in having you memorize PDFs of special +distributions we're not interested in + + align:start position:0% +distributions we're not interested in + + + align:start position:0% +distributions we're not interested in +having you memorize the uh the + + align:start position:0% +having you memorize the uh the + + + align:start position:0% +having you memorize the uh the +expectation and the variance of special + + align:start position:0% +expectation and the variance of special + + + align:start position:0% +expectation and the variance of special +distributions um sometimes that just + + align:start position:0% +distributions um sometimes that just + + + align:start position:0% +distributions um sometimes that just +happens because you use them so much but + + align:start position:0% +happens because you use them so much but + + + align:start position:0% +happens because you use them so much but +um so on the exam so if you feel + + align:start position:0% +um so on the exam so if you feel + + + align:start position:0% +um so on the exam so if you feel +comfortable you can sort of write them + + align:start position:0% +comfortable you can sort of write them + + + align:start position:0% +comfortable you can sort of write them +out on your your page of notes that you + + align:start position:0% +out on your your page of notes that you + + + align:start position:0% +out on your your page of notes that you +bring in but we'll also provide things + + align:start position:0% +bring in but we'll also provide things + + + align:start position:0% +bring in but we'll also provide things +like that on the exam okay + + align:start position:0% +like that on the exam okay + + + align:start position:0% +like that on the exam okay +um and then finally uh in the last + + align:start position:0% +um and then finally uh in the last + + + align:start position:0% +um and then finally uh in the last +couple of lectures we started talking + + align:start position:0% +couple of lectures we started talking + + + align:start position:0% +couple of lectures we started talking +about estimation so we started our + + align:start position:0% +about estimation so we started our + + + align:start position:0% +about estimation so we started our +segue + + align:start position:0% +segue + + + align:start position:0% +segue +into um estimation in some sense was the + + align:start position:0% +into um estimation in some sense was the + + + align:start position:0% +into um estimation in some sense was the +central limit theorem so we've been + + align:start position:0% +central limit theorem so we've been + + + align:start position:0% +central limit theorem so we've been +talking about functions of random + + align:start position:0% +talking about functions of random + + + align:start position:0% +talking about functions of random +variables and we introduced a a special + + align:start position:0% +variables and we introduced a a special + + + align:start position:0% +variables and we introduced a a special +particularly useful function of random + + align:start position:0% +particularly useful function of random + + + align:start position:0% +particularly useful function of random +variables called the sample mean and we + + align:start position:0% +variables called the sample mean and we + + + align:start position:0% +variables called the sample mean and we +computed what the expect + + align:start position:0% +computed what the expect + + + align:start position:0% +computed what the expect +of that that function was what the + + align:start position:0% +of that that function was what the + + + align:start position:0% +of that that function was what the +expectation of the sample mean is we + + align:start position:0% +expectation of the sample mean is we + + + align:start position:0% +expectation of the sample mean is we +computed what the variance of that + + align:start position:0% +computed what the variance of that + + + align:start position:0% +computed what the variance of that +sample mean was but we wanted to know + + align:start position:0% +sample mean was but we wanted to know + + + align:start position:0% +sample mean was but we wanted to know +even more about its characteristics and + + align:start position:0% +even more about its characteristics and + + + align:start position:0% +even more about its characteristics and +how it was distributed and the central + + align:start position:0% +how it was distributed and the central + + + align:start position:0% +how it was distributed and the central +limit themm told us that the C Central + + align:start position:0% +limit themm told us that the C Central + + + align:start position:0% +limit themm told us that the C Central +limit them had this sort of remarkable + + align:start position:0% +limit them had this sort of remarkable + + + align:start position:0% +limit them had this sort of remarkable +result that no matter what kind of + + align:start position:0% +result that no matter what kind of + + + align:start position:0% +result that no matter what kind of +distribution you're drawing from and + + align:start position:0% +distribution you're drawing from and + + + align:start position:0% +distribution you're drawing from and +Computing the sample mean of if your + + align:start position:0% +Computing the sample mean of if your + + + align:start position:0% +Computing the sample mean of if your +sample size is big enough from that + + align:start position:0% +sample size is big enough from that + + + align:start position:0% +sample size is big enough from that +crazy + + align:start position:0% +crazy + + + align:start position:0% +crazy +distribution uh then the sample mean is + + align:start position:0% +distribution uh then the sample mean is + + + align:start position:0% +distribution uh then the sample mean is +have approximately a normal distribution + + align:start position:0% +have approximately a normal distribution + + + align:start position:0% +have approximately a normal distribution +okay and that's just super + + align:start position:0% +okay and that's just super + + + align:start position:0% +okay and that's just super +useful um the the full usefulness of it + + align:start position:0% +useful um the the full usefulness of it + + + align:start position:0% +useful um the the full usefulness of it +has not occurred to you yet because we + + align:start position:0% +has not occurred to you yet because we + + + align:start position:0% +has not occurred to you yet because we +haven't gotten to inference but uh we + + align:start position:0% +haven't gotten to inference but uh we + + + align:start position:0% +haven't gotten to inference but uh we +will after spring break get to inference + + align:start position:0% +will after spring break get to inference + + + align:start position:0% +will after spring break get to inference +and then you will know okay so we talked + + align:start position:0% +and then you will know okay so we talked + + + align:start position:0% +and then you will know okay so we talked +about the central we talked about the + + align:start position:0% +about the central we talked about the + + + align:start position:0% +about the central we talked about the +sample mean so that's that's kind of the + + align:start position:0% +sample mean so that's that's kind of the + + + align:start position:0% +sample mean so that's that's kind of the +most important estimator that we talked + + align:start position:0% +most important estimator that we talked + + + align:start position:0% +most important estimator that we talked +about we talked about the central limit + + align:start position:0% +about we talked about the central limit + + + align:start position:0% +about we talked about the central limit +theem which told us some important facts + + align:start position:0% +theem which told us some important facts + + + align:start position:0% +theem which told us some important facts +about the the how the sample mean + + align:start position:0% +about the the how the sample mean + + + align:start position:0% +about the the how the sample mean +behaved uh we had sort of a general + + align:start position:0% +behaved uh we had sort of a general + + + align:start position:0% +behaved uh we had sort of a general +discussion um about estimation and then + + align:start position:0% +discussion um about estimation and then + + + align:start position:0% +discussion um about estimation and then +the last two topics we covered these are + + align:start position:0% +the last two topics we covered these are + + + align:start position:0% +the last two topics we covered these are +topics that we will not test you on on + + align:start position:0% +topics that we will not test you on on + + + align:start position:0% +topics that we will not test you on on +the exam the last two topics we covered + + align:start position:0% +the exam the last two topics we covered + + + align:start position:0% +the exam the last two topics we covered +were criteria for assessing estimators + + align:start position:0% +were criteria for assessing estimators + + + align:start position:0% +were criteria for assessing estimators +so whether an estimator is unbiased + + align:start position:0% +so whether an estimator is unbiased + + + align:start position:0% +so whether an estimator is unbiased +whether it's efficient whether it's a + + align:start position:0% +whether it's efficient whether it's a + + + align:start position:0% +whether it's efficient whether it's a +minimum me squared error estimator + + align:start position:0% +minimum me squared error estimator + + + align:start position:0% +minimum me squared error estimator +whether it's consistent um and then we + + align:start position:0% +whether it's consistent um and then we + + + align:start position:0% +whether it's consistent um and then we +also talked about uh Frameworks for + + align:start position:0% +also talked about uh Frameworks for + + + align:start position:0% +also talked about uh Frameworks for +deriving estimators um method of moments + + align:start position:0% +deriving estimators um method of moments + + + align:start position:0% +deriving estimators um method of moments +estimation and maximum likelihood + + align:start position:0% +estimation and maximum likelihood + + + align:start position:0% +estimation and maximum likelihood +estimation + + align:start position:0% + + + + align:start position:0% + +okay \ No newline at end of file diff --git a/2N0OXAiX-BM.txt b/2N0OXAiX-BM.txt new file mode 100644 index 0000000000000000000000000000000000000000..1261208cc0a89b137ec031568dd07a0c8233de24 --- /dev/null +++ b/2N0OXAiX-BM.txt @@ -0,0 +1,3419 @@ +align:start position:0% + +a new way of thinking about this is + + align:start position:0% +a new way of thinking about this is + + + align:start position:0% +a new way of thinking about this is +based on integral equations so it's a + + align:start position:0% +based on integral equations so it's a + + + align:start position:0% +based on integral equations so it's a +nice method of it's less complicated + + align:start position:0% +nice method of it's less complicated + + + align:start position:0% +nice method of it's less complicated +than it seems and it leads to some + + align:start position:0% +than it seems and it leads to some + + + align:start position:0% +than it seems and it leads to some +expressions for the scattering amplitude + + align:start position:0% +expressions for the scattering amplitude + + + align:start position:0% +expressions for the scattering amplitude +we'll find another formula for this + + align:start position:0% +we'll find another formula for this + + + align:start position:0% +we'll find another formula for this +quantity f of K of theta when we cannot + + align:start position:0% +quantity f of K of theta when we cannot + + + align:start position:0% +quantity f of K of theta when we cannot +calculate it with phase shifts but phase + + align:start position:0% +calculate it with phase shifts but phase + + + align:start position:0% +calculate it with phase shifts but phase +shifts is very powerful if your prompt + + align:start position:0% +shifts is very powerful if your prompt + + + align:start position:0% +shifts is very powerful if your prompt +has spherical symmetry it's it's + + align:start position:0% +has spherical symmetry it's it's + + + align:start position:0% +has spherical symmetry it's it's +probably the first thing you try because + + align:start position:0% +probably the first thing you try because + + + align:start position:0% +probably the first thing you try because +there's nothing to prevent you from + + align:start position:0% +there's nothing to prevent you from + + + align:start position:0% +there's nothing to prevent you from +finding a solution in that case ok so + + align:start position:0% +finding a solution in that case ok so + + + align:start position:0% +finding a solution in that case ok so +integral equations so integral + + align:start position:0% +integral equations so integral + + + align:start position:0% +integral equations so integral +scattering equation scattering so what + + align:start position:0% +scattering equation scattering so what + + + align:start position:0% +scattering equation scattering so what +are we solving we're solving minus H + + align:start position:0% +are we solving we're solving minus H + + + align:start position:0% +are we solving we're solving minus H +squared over 2m laplacian plus V of R a + + align:start position:0% +squared over 2m laplacian plus V of R a + + + align:start position:0% +squared over 2m laplacian plus V of R a +potential that is not necessarily + + align:start position:0% +potential that is not necessarily + + + align:start position:0% +potential that is not necessarily +spherical equals or acts on apps ifr to + + align:start position:0% +spherical equals or acts on apps ifr to + + + align:start position:0% +spherical equals or acts on apps ifr to +give you h squared K squared over 2m psy + + align:start position:0% +give you h squared K squared over 2m psy + + + align:start position:0% +give you h squared K squared over 2m psy +of our so it's an equation for + + align:start position:0% +of our so it's an equation for + + + align:start position:0% +of our so it's an equation for +eigenstates the sharing their equation + + align:start position:0% +eigenstates the sharing their equation + + + align:start position:0% +eigenstates the sharing their equation +right it's good it's nice and this is + + align:start position:0% +right it's good it's nice and this is + + + align:start position:0% +right it's good it's nice and this is +what we've been solving we've been + + align:start position:0% +what we've been solving we've been + + + align:start position:0% +what we've been solving we've been +solving it for some particular cases the + + align:start position:0% +solving it for some particular cases the + + + align:start position:0% +solving it for some particular cases the +case of physical interest for us was + + align:start position:0% +case of physical interest for us was + + + align:start position:0% +case of physical interest for us was +when there was a plane wave coming in + + align:start position:0% +when there was a plane wave coming in + + + align:start position:0% +when there was a plane wave coming in +from infinity and a spherical wave going + + align:start position:0% +from infinity and a spherical wave going + + + align:start position:0% +from infinity and a spherical wave going +out at infinity now I + + align:start position:0% +out at infinity now I + + + align:start position:0% +out at infinity now I +this moment is probably convenient to + + align:start position:0% +this moment is probably convenient to + + + align:start position:0% +this moment is probably convenient to +clean up the units from this equation a + + align:start position:0% +clean up the units from this equation a + + + align:start position:0% +clean up the units from this equation a +little so I'll use a notation in which V + + align:start position:0% +little so I'll use a notation in which V + + + align:start position:0% +little so I'll use a notation in which V +of R is equal to H squared over 2m u of + + align:start position:0% +of R is equal to H squared over 2m u of + + + align:start position:0% +of R is equal to H squared over 2m u of +r u still reminds you of a potential I + + align:start position:0% +r u still reminds you of a potential I + + + align:start position:0% +r u still reminds you of a potential I +think and it's a good thing it's a + + align:start position:0% +think and it's a good thing it's a + + + align:start position:0% +think and it's a good thing it's a +definition of U of our it's definition + + align:start position:0% +definition of U of our it's definition + + + align:start position:0% +definition of U of our it's definition +and in that way I could get rid of the H + + align:start position:0% +and in that way I could get rid of the H + + + align:start position:0% +and in that way I could get rid of the H +bars in the Schrodinger equation and + + align:start position:0% +bars in the Schrodinger equation and + + + align:start position:0% +bars in the Schrodinger equation and +what do we get we get minus laplacian + + align:start position:0% +what do we get we get minus laplacian + + + align:start position:0% +what do we get we get minus laplacian +plus u of r acting on Phi of R is equal + + align:start position:0% +plus u of r acting on Phi of R is equal + + + align:start position:0% +plus u of r acting on Phi of R is equal +to K squared acting on so far ok that + + align:start position:0% +to K squared acting on so far ok that + + + align:start position:0% +to K squared acting on so far ok that +looks nice + + align:start position:0% +looks nice + + + align:start position:0% +looks nice +it probably is nicer if you put it in a + + align:start position:0% +it probably is nicer if you put it in a + + + align:start position:0% +it probably is nicer if you put it in a +way that the left hand side is kind of a + + align:start position:0% +way that the left hand side is kind of a + + + align:start position:0% +way that the left hand side is kind of a +nice simple operator and the right hand + + align:start position:0% +nice simple operator and the right hand + + + align:start position:0% +nice simple operator and the right hand +side involves a potential so I will move + + align:start position:0% +side involves a potential so I will move + + + align:start position:0% +side involves a potential so I will move +it along so that I can pass the nablus + + align:start position:0% +it along so that I can pass the nablus + + + align:start position:0% +it along so that I can pass the nablus +squared to the ripe and then make that + + align:start position:0% +squared to the ripe and then make that + + + align:start position:0% +squared to the ripe and then make that +the left hand side so this will be + + align:start position:0% +the left hand side so this will be + + + align:start position:0% +the left hand side so this will be +laplacian squared plus K squared on psy + + align:start position:0% +laplacian squared plus K squared on psy + + + align:start position:0% +laplacian squared plus K squared on psy +of r is equal to u of r sy afar okay so + + align:start position:0% +of r is equal to u of r sy afar okay so + + + align:start position:0% +of r is equal to u of r sy afar okay so +with written with we've done nothing so + + align:start position:0% +with written with we've done nothing so + + + align:start position:0% +with written with we've done nothing so +far + + align:start position:0% +far + + + align:start position:0% +far +except put the equation in a way that + + align:start position:0% +except put the equation in a way that + + + align:start position:0% +except put the equation in a way that +stimulates our thinking we kind of think + + align:start position:0% +stimulates our thinking we kind of think + + + align:start position:0% +stimulates our thinking we kind of think +of the right-hand side as a source and + + align:start position:0% +of the right-hand side as a source and + + + align:start position:0% +of the right-hand side as a source and +the left hand side as + + align:start position:0% +the left hand side as + + + align:start position:0% +the left hand side as +kind of the equation you want to solve + + align:start position:0% +kind of the equation you want to solve + + + align:start position:0% +kind of the equation you want to solve +sometimes you have an equation like that + + align:start position:0% +sometimes you have an equation like that + + + align:start position:0% +sometimes you have an equation like that +and you can get this zero here well + + align:start position:0% +and you can get this zero here well + + + align:start position:0% +and you can get this zero here well +that's when the potential is zero but + + align:start position:0% +that's when the potential is zero but + + + align:start position:0% +that's when the potential is zero but +sometimes there's a bit of potential so + + align:start position:0% +sometimes there's a bit of potential so + + + align:start position:0% +sometimes there's a bit of potential so +the solution feeds back into this + + align:start position:0% +the solution feeds back into this + + + align:start position:0% +the solution feeds back into this +whenever you have an equation of this + + align:start position:0% +whenever you have an equation of this + + + align:start position:0% +whenever you have an equation of this +form some nice operator so this we call + + align:start position:0% +form some nice operator so this we call + + + align:start position:0% +form some nice operator so this we call +nice operator acting on sigh giving you + + align:start position:0% +nice operator acting on sigh giving you + + + align:start position:0% +nice operator acting on sigh giving you +something that depends on side that + + align:start position:0% +something that depends on side that + + + align:start position:0% +something that depends on side that +maybe it's not that nice or not that + + align:start position:0% +maybe it's not that nice or not that + + + align:start position:0% +maybe it's not that nice or not that +simple we can try to solve this using a + + align:start position:0% +simple we can try to solve this using a + + + align:start position:0% +simple we can try to solve this using a +greens function + + align:start position:0% +greens function + + + align:start position:0% +greens function +that's what greens functions are good + + align:start position:0% +that's what greens functions are good + + + align:start position:0% +that's what greens functions are good +for so let's try to use the greens + + align:start position:0% +for so let's try to use the greens + + + align:start position:0% +for so let's try to use the greens +function so what is a greens function it + + align:start position:0% +function so what is a greens function it + + + align:start position:0% +function so what is a greens function it +is basically a way of understanding what + + align:start position:0% +is basically a way of understanding what + + + align:start position:0% +is basically a way of understanding what +this operator is so nice operator must + + align:start position:0% +this operator is so nice operator must + + + align:start position:0% +this operator is so nice operator must +have a greens function so what is your + + align:start position:0% +have a greens function so what is your + + + align:start position:0% +have a greens function so what is your +greens function here it's called G and + + align:start position:0% + + + + align:start position:0% + +we say it's depends on R minus R prime R + + align:start position:0% +we say it's depends on R minus R prime R + + + align:start position:0% +we say it's depends on R minus R prime R +prime is an arbitrary point so far but + + align:start position:0% +prime is an arbitrary point so far but + + + align:start position:0% +prime is an arbitrary point so far but +here is what it does it's it's basically + + align:start position:0% +here is what it does it's it's basically + + + align:start position:0% +here is what it does it's it's basically +a solution + + align:start position:0% + + + + align:start position:0% + +you want this greens function to be + + align:start position:0% +you want this greens function to be + + + align:start position:0% +you want this greens function to be +almost zero except they're not quite + + align:start position:0% +almost zero except they're not quite + + + align:start position:0% +almost zero except they're not quite +equal to zero you want it to be equal to + + align:start position:0% +equal to zero you want it to be equal to + + + align:start position:0% +equal to zero you want it to be equal to +a delta function so so that's the + + align:start position:0% +a delta function so so that's the + + + align:start position:0% +a delta function so so that's the +definition of the greens function is + + align:start position:0% +definition of the greens function is + + + align:start position:0% +definition of the greens function is +that thing which is the solution of a + + align:start position:0% +that thing which is the solution of a + + + align:start position:0% +that thing which is the solution of a +similar equation when you have the nice + + align:start position:0% +similar equation when you have the nice + + + align:start position:0% +similar equation when you have the nice +operator acting on the greens function + + align:start position:0% +operator acting on the greens function + + + align:start position:0% +operator acting on the greens function +being just a delta function it's almost + + align:start position:0% +being just a delta function it's almost + + + align:start position:0% +being just a delta function it's almost +saying that the greens function is the + + align:start position:0% +saying that the greens function is the + + + align:start position:0% +saying that the greens function is the +thing that solves that equation with + + align:start position:0% +thing that solves that equation with + + + align:start position:0% +thing that solves that equation with +zero on the right hand side except that + + align:start position:0% +zero on the right hand side except that + + + align:start position:0% +zero on the right hand side except that +it's not really zero it's a source in + + align:start position:0% +it's not really zero it's a source in + + + align:start position:0% +it's not really zero it's a source in +the right hand side it's a delta + + align:start position:0% +the right hand side it's a delta + + + align:start position:0% +the right hand side it's a delta +function at this point so you would say + + align:start position:0% +function at this point so you would say + + + align:start position:0% +function at this point so you would say +maybe okay I don't know that why would I + + align:start position:0% +maybe okay I don't know that why would I + + + align:start position:0% +maybe okay I don't know that why would I +care about this equation you care for + + align:start position:0% +care about this equation you care for + + + align:start position:0% +care about this equation you care for +two reasons the first reason is that + + align:start position:0% +two reasons the first reason is that + + + align:start position:0% +two reasons the first reason is that +this equation is easier to solve than + + align:start position:0% +this equation is easier to solve than + + + align:start position:0% +this equation is easier to solve than +this one doesn't involve the potential + + align:start position:0% +this one doesn't involve the potential + + + align:start position:0% +this one doesn't involve the potential +which is complicated it just involves a + + align:start position:0% +which is complicated it just involves a + + + align:start position:0% +which is complicated it just involves a +delta function so we can have this G and + + align:start position:0% +delta function so we can have this G and + + + align:start position:0% +delta function so we can have this G and +solve it once because it doesn't involve + + align:start position:0% +solve it once because it doesn't involve + + + align:start position:0% +solve it once because it doesn't involve +the potential and then the great thing + + align:start position:0% +the potential and then the great thing + + + align:start position:0% +the potential and then the great thing +about this equation is that it allows + + align:start position:0% +about this equation is that it allows + + + align:start position:0% +about this equation is that it allows +you to write a solution for the top + + align:start position:0% +you to write a solution for the top + + + align:start position:0% +you to write a solution for the top +equation without having to do any work + + align:start position:0% +equation without having to do any work + + + align:start position:0% +equation without having to do any work +anymore once you have the greens + + align:start position:0% +anymore once you have the greens + + + align:start position:0% +anymore once you have the greens +function you're done so let's assume you + + align:start position:0% +function you're done so let's assume you + + + align:start position:0% +function you're done so let's assume you +have the greens function how would you + + align:start position:0% +have the greens function how would you + + + align:start position:0% +have the greens function how would you +write the solution for this equation so + + align:start position:0% +write the solution for this equation so + + + align:start position:0% +write the solution for this equation so +the idea is superposition basically + + align:start position:0% +the idea is superposition basically + + + align:start position:0% +the idea is superposition basically +and we'll do it using that so our aim is + + align:start position:0% +and we'll do it using that so our aim is + + + align:start position:0% +and we'll do it using that so our aim is +to use this greens function if we had it + + align:start position:0% +to use this greens function if we had it + + + align:start position:0% +to use this greens function if we had it +to write a solution for this equation so + + align:start position:0% +to write a solution for this equation so + + + align:start position:0% +to write a solution for this equation so +here is the claim you write sine of X is + + align:start position:0% +here is the claim you write sine of X is + + + align:start position:0% +here is the claim you write sine of X is +it going to be given by a beginning one + + align:start position:0% +it going to be given by a beginning one + + + align:start position:0% +it going to be given by a beginning one +size zero of X that is going to be a + + align:start position:0% +size zero of X that is going to be a + + + align:start position:0% +size zero of X that is going to be a +funny one this one solves laplacian plus + + align:start position:0% +funny one this one solves laplacian plus + + + align:start position:0% +funny one this one solves laplacian plus +K squared on size zero of X or R is + + align:start position:0% +K squared on size zero of X or R is + + + align:start position:0% +K squared on size zero of X or R is +equal to zero so whenever you have an + + align:start position:0% +equal to zero so whenever you have an + + + align:start position:0% +equal to zero so whenever you have an +equation of this form you can add any a + + align:start position:0% +equation of this form you can add any a + + + align:start position:0% +equation of this form you can add any a +solution anything that this killed by + + align:start position:0% +solution anything that this killed by + + + align:start position:0% +solution anything that this killed by +this can be added to whatever solution + + align:start position:0% +this can be added to whatever solution + + + align:start position:0% +this can be added to whatever solution +you have so let's assume that we have a + + align:start position:0% +you have so let's assume that we have a + + + align:start position:0% +you have so let's assume that we have a +solution of this form size zero of this + + align:start position:0% +solution of this form size zero of this + + + align:start position:0% +solution of this form size zero of this +form now here I'll add one more thing + + align:start position:0% +form now here I'll add one more thing + + + align:start position:0% +form now here I'll add one more thing +the important part is going to be an + + align:start position:0% +the important part is going to be an + + + align:start position:0% +the important part is going to be an +integral over our prime here is the + + align:start position:0% +integral over our prime here is the + + + align:start position:0% +integral over our prime here is the +superposition I'm going to think of this + + align:start position:0% +superposition I'm going to think of this + + + align:start position:0% +superposition I'm going to think of this +potential you are far as kind of + + align:start position:0% +potential you are far as kind of + + + align:start position:0% +potential you are far as kind of +existing at every point R prime so I'm + + align:start position:0% +existing at every point R prime so I'm + + + align:start position:0% +existing at every point R prime so I'm +going to write the solution as a + + align:start position:0% +going to write the solution as a + + + align:start position:0% +going to write the solution as a +superposition that involves the greens + + align:start position:0% +superposition that involves the greens + + + align:start position:0% +superposition that involves the greens +function so this will be G of R minus R + + align:start position:0% +function so this will be G of R minus R + + + align:start position:0% +function so this will be G of R minus R +prime times u of r prime times + + align:start position:0% +prime times u of r prime times + + + align:start position:0% +prime times u of r prime times +sy of R Prime + + align:start position:0% + + + + align:start position:0% + +I claim that this is equivalent to this + + align:start position:0% +I claim that this is equivalent to this + + + align:start position:0% +I claim that this is equivalent to this +equation that we have that this side + + align:start position:0% +equation that we have that this side + + + align:start position:0% +equation that we have that this side +provides more than equivalent + + align:start position:0% +provides more than equivalent + + + align:start position:0% +provides more than equivalent +I think the precise way to say this + + align:start position:0% +I think the precise way to say this + + + align:start position:0% +I think the precise way to say this +provides a solution of this equation the + + align:start position:0% +provides a solution of this equation the + + + align:start position:0% +provides a solution of this equation the +way I've written so let's try it + + align:start position:0% +way I've written so let's try it + + + align:start position:0% +way I've written so let's try it +suppose I calculate laplacian plus K + + align:start position:0% +suppose I calculate laplacian plus K + + + align:start position:0% +suppose I calculate laplacian plus K +squared on side effects here okay the + + align:start position:0% +squared on side effects here okay the + + + align:start position:0% +squared on side effects here okay the +first term it's already zero so + + align:start position:0% +first term it's already zero so + + + align:start position:0% +first term it's already zero so +laplacian plus K squared on size zero is + + align:start position:0% +laplacian plus K squared on size zero is + + + align:start position:0% +laplacian plus K squared on size zero is +already zero and then I come here and I + + align:start position:0% +already zero and then I come here and I + + + align:start position:0% +already zero and then I come here and I +say ok I'm a laplacian I care about our + + align:start position:0% +say ok I'm a laplacian I care about our + + + align:start position:0% +say ok I'm a laplacian I care about our +because I'm a depression I don't care + + align:start position:0% +because I'm a depression I don't care + + + align:start position:0% +because I'm a depression I don't care +about our prime so I come in here and I + + align:start position:0% +about our prime so I come in here and I + + + align:start position:0% +about our prime so I come in here and I +ignore our prime ignore our prime I + + align:start position:0% +ignore our prime ignore our prime I + + + align:start position:0% +ignore our prime ignore our prime I +cannot ignore this thing so we have plus + + align:start position:0% +cannot ignore this thing so we have plus + + + align:start position:0% +cannot ignore this thing so we have plus +integral D our prime laplacian plus K + + align:start position:0% +integral D our prime laplacian plus K + + + align:start position:0% +integral D our prime laplacian plus K +squared acting on G of our minus R prime + + align:start position:0% + + + + align:start position:0% + +times U of R Prime sy of our prime and + + align:start position:0% +times U of R Prime sy of our prime and + + + align:start position:0% +times U of R Prime sy of our prime and +now because the greens function was + + align:start position:0% +now because the greens function was + + + align:start position:0% +now because the greens function was +designed to give you a delta of R minus + + align:start position:0% +designed to give you a delta of R minus + + + align:start position:0% +designed to give you a delta of R minus +R prime this is an integral that can be + + align:start position:0% +R prime this is an integral that can be + + + align:start position:0% +R prime this is an integral that can be +done the integral over R Prime and just + + align:start position:0% +done the integral over R Prime and just + + + align:start position:0% +done the integral over R Prime and just +set the rest of the integrand at the + + align:start position:0% +set the rest of the integrand at the + + + align:start position:0% +set the rest of the integrand at the +point R because you integrate over R + + align:start position:0% +point R because you integrate over R + + + align:start position:0% +point R because you integrate over R +Prime and this Delta function fires when + + align:start position:0% +Prime and this Delta function fires when + + + align:start position:0% +Prime and this Delta function fires when +our R + + align:start position:0% +our R + + + align:start position:0% +our R +is equal to R so this gives me you of + + align:start position:0% +is equal to R so this gives me you of + + + align:start position:0% +is equal to R so this gives me you of +our sigh of our and that is the equation + + align:start position:0% +our sigh of our and that is the equation + + + align:start position:0% +our sigh of our and that is the equation +I wanted to solve the question that we + + align:start position:0% +I wanted to solve the question that we + + + align:start position:0% +I wanted to solve the question that we +have here so we have turned the problem + + align:start position:0% +have here so we have turned the problem + + + align:start position:0% +have here so we have turned the problem +this cannot be called the solution + + align:start position:0% +this cannot be called the solution + + + align:start position:0% +this cannot be called the solution +because we have not solved it we have + + align:start position:0% +because we have not solved it we have + + + align:start position:0% +because we have not solved it we have +turned the problem into a different kind + + align:start position:0% +turned the problem into a different kind + + + align:start position:0% +turned the problem into a different kind +of problem we it might even seem that + + align:start position:0% +of problem we it might even seem that + + + align:start position:0% +of problem we it might even seem that +we've made the problem worse by turning + + align:start position:0% +we've made the problem worse by turning + + + align:start position:0% +we've made the problem worse by turning +this into an integral equation there's + + align:start position:0% +this into an integral equation there's + + + align:start position:0% +this into an integral equation there's +no derivatives here but the function + + align:start position:0% +no derivatives here but the function + + + align:start position:0% +no derivatives here but the function +that you're looking for appears outside + + align:start position:0% +that you're looking for appears outside + + + align:start position:0% +that you're looking for appears outside +and inside the integral so these things + + align:start position:0% +and inside the integral so these things + + + align:start position:0% +and inside the integral so these things +are called integral equations and and + + align:start position:0% +are called integral equations and and + + + align:start position:0% +are called integral equations and and +the power of an integral equation is the + + align:start position:0% +the power of an integral equation is the + + + align:start position:0% +the power of an integral equation is the +insight it can give you once you have an + + align:start position:0% +insight it can give you once you have an + + + align:start position:0% +insight it can give you once you have an +idea of what the green's function is and + + align:start position:0% +idea of what the green's function is and + + + align:start position:0% +idea of what the green's function is and +also it's a good place to do a recursive + + align:start position:0% +also it's a good place to do a recursive + + + align:start position:0% +also it's a good place to do a recursive +approximations in that you can + + align:start position:0% +approximations in that you can + + + align:start position:0% +approximations in that you can +essentially begin and say ok i know the + + align:start position:0% +essentially begin and say ok i know the + + + align:start position:0% +essentially begin and say ok i know the +wave function is this plus that but + + align:start position:0% +wave function is this plus that but + + + align:start position:0% +wave function is this plus that but +maybe if in some sense i can think of + + align:start position:0% +maybe if in some sense i can think of + + + align:start position:0% +maybe if in some sense i can think of +this thing as the leading solution i + + align:start position:0% +this thing as the leading solution i + + + align:start position:0% +this thing as the leading solution i +could substitute the living solution in + + align:start position:0% +could substitute the living solution in + + + align:start position:0% +could substitute the living solution in +here and try to make an approximation + + align:start position:0% +here and try to make an approximation + + + align:start position:0% +here and try to make an approximation +that's gonna give you a nice + + align:start position:0% +that's gonna give you a nice + + + align:start position:0% +that's gonna give you a nice +approximation the born approximation + + align:start position:0% +approximation the born approximation + + + align:start position:0% +approximation the born approximation +we'll see that soon now that should be + + align:start position:0% +we'll see that soon now that should be + + + align:start position:0% +we'll see that soon now that should be +upside ours I think I'm using R so I + + align:start position:0% +upside ours I think I'm using R so I + + + align:start position:0% +upside ours I think I'm using R so I +please so ours and ours yeah no no + + align:start position:0% +please so ours and ours yeah no no + + + align:start position:0% +please so ours and ours yeah no no +difference at this moment ok so the next + + align:start position:0% +difference at this moment ok so the next + + + align:start position:0% +difference at this moment ok so the next +step is solving for the greens function + + align:start position:0% +step is solving for the greens function + + + align:start position:0% +step is solving for the greens function +we need the greens function otherwise we + + align:start position:0% +we need the greens function otherwise we + + + align:start position:0% +we need the greens function otherwise we +cannot make progress with this equation + + align:start position:0% +cannot make progress with this equation + + + align:start position:0% +cannot make progress with this equation +so I'm gonna do a simple solution of the + + align:start position:0% +so I'm gonna do a simple solution of the + + + align:start position:0% +so I'm gonna do a simple solution of the +greens function basically by doing a + + align:start position:0% +greens function basically by doing a + + + align:start position:0% +greens function basically by doing a +couple of checks and saying that is the + + align:start position:0% +couple of checks and saying that is the + + + align:start position:0% +couple of checks and saying that is the +answer we're interested in and and there + + align:start position:0% +answer we're interested in and and there + + + align:start position:0% +answer we're interested in and and there +are several possible greens functions + + align:start position:0% +are several possible greens functions + + + align:start position:0% +are several possible greens functions +and depending on the problem you're + + align:start position:0% +and depending on the problem you're + + + align:start position:0% +and depending on the problem you're +solving you choose the right greens + + align:start position:0% +solving you choose the right greens + + + align:start position:0% +solving you choose the right greens +function and we'll choose the one that + + align:start position:0% +function and we'll choose the one that + + + align:start position:0% +function and we'll choose the one that +is suitable for us now this is a + + align:start position:0% +is suitable for us now this is a + + + align:start position:0% +is suitable for us now this is a +something that can be done the general + + align:start position:0% +something that can be done the general + + + align:start position:0% +something that can be done the general +solutions can be obtained by contour + + align:start position:0% +solutions can be obtained by contour + + + align:start position:0% +solutions can be obtained by contour +integration and there are all kinds of + + align:start position:0% +integration and there are all kinds of + + + align:start position:0% +integration and there are all kinds of +nice methods to do this but in fact in + + align:start position:0% +nice methods to do this but in fact in + + + align:start position:0% +nice methods to do this but in fact in +this case it's really simple you don't + + align:start position:0% +this case it's really simple you don't + + + align:start position:0% +this case it's really simple you don't +need any of those complicated things you + + align:start position:0% +need any of those complicated things you + + + align:start position:0% +need any of those complicated things you +can just pretty much write the solution + + align:start position:0% +can just pretty much write the solution + + + align:start position:0% +can just pretty much write the solution +so that's what I'm gonna do so what do + + align:start position:0% +so that's what I'm gonna do so what do + + + align:start position:0% +so that's what I'm gonna do so what do +we need for the greens function so we + + align:start position:0% +we need for the greens function so we + + + align:start position:0% +we need for the greens function so we +have a greens function that depends on R + + align:start position:0% +have a greens function that depends on R + + + align:start position:0% +have a greens function that depends on R +minus R prime okay and so it depends on + + align:start position:0% +minus R prime okay and so it depends on + + + align:start position:0% +minus R prime okay and so it depends on +a vector so let me simplify the matter + + align:start position:0% +a vector so let me simplify the matter + + + align:start position:0% +a vector so let me simplify the matter +by saying okay since it depends on a + + align:start position:0% +by saying okay since it depends on a + + + align:start position:0% +by saying okay since it depends on a +vector + + align:start position:0% +vector + + + align:start position:0% +vector +I'll just first calculate what is G of + + align:start position:0% +I'll just first calculate what is G of + + + align:start position:0% +I'll just first calculate what is G of +are the greens function of R when the + + align:start position:0% +are the greens function of R when the + + + align:start position:0% +are the greens function of R when the +vector is R or you can think it's when + + align:start position:0% +vector is R or you can think it's when + + + align:start position:0% +vector is R or you can think it's when +our prime is equal to zero whatever I + + align:start position:0% +our prime is equal to zero whatever I + + + align:start position:0% +our prime is equal to zero whatever I +find for G of our this one is obtained + + align:start position:0% +find for G of our this one is obtained + + + align:start position:0% +find for G of our this one is obtained +by whatever I find here put in instead R + + align:start position:0% +by whatever I find here put in instead R + + + align:start position:0% +by whatever I find here put in instead R +minus R prime so GFR is enough for what + + align:start position:0% +minus R prime so GFR is enough for what + + + align:start position:0% +minus R prime so GFR is enough for what +we want to do so it should have + + align:start position:0% +we want to do so it should have + + + align:start position:0% +we want to do so it should have +laplacian + + align:start position:0% +laplacian + + + align:start position:0% +laplacian +plus K squared on G of our should be + + align:start position:0% +plus K squared on G of our should be + + + align:start position:0% +plus K squared on G of our should be +four not 4pi it's Delta of our okay so + + align:start position:0% +four not 4pi it's Delta of our okay so + + + align:start position:0% +four not 4pi it's Delta of our okay so +we've looked at that in fact at the + + align:start position:0% +we've looked at that in fact at the + + + align:start position:0% +we've looked at that in fact at the +beginning of this course not of this + + align:start position:0% +beginning of this course not of this + + + align:start position:0% +beginning of this course not of this +course of the discussion of scattering + + align:start position:0% +course of the discussion of scattering + + + align:start position:0% +course of the discussion of scattering +we looked at this equation in fact we + + align:start position:0% +we looked at this equation in fact we + + + align:start position:0% +we looked at this equation in fact we +wanted to solve it when the right-hand + + align:start position:0% +wanted to solve it when the right-hand + + + align:start position:0% +wanted to solve it when the right-hand +side was 0 to find solutions of the + + align:start position:0% +side was 0 to find solutions of the + + + align:start position:0% +side was 0 to find solutions of the +Schrodinger equation and we found that + + align:start position:0% +Schrodinger equation and we found that + + + align:start position:0% +Schrodinger equation and we found that +this G's could be of the form e to the I + + align:start position:0% +this G's could be of the form e to the I + + + align:start position:0% +this G's could be of the form e to the I +K R plus minus IKr over R those were the + + align:start position:0% +K R plus minus IKr over R those were the + + + align:start position:0% +K R plus minus IKr over R those were the +spherical waves that solved this + + align:start position:0% +spherical waves that solved this + + + align:start position:0% +spherical waves that solved this +equation with zero potential those are + + align:start position:0% +equation with zero potential those are + + + align:start position:0% +equation with zero potential those are +our solutions now it's easy to see that + + align:start position:0% +our solutions now it's easy to see that + + + align:start position:0% +our solutions now it's easy to see that +laplacian plus K squared on this g that + + align:start position:0% +laplacian plus K squared on this g that + + + align:start position:0% +laplacian plus K squared on this g that +has a plus or minus is equal to zero for + + align:start position:0% +has a plus or minus is equal to zero for + + + align:start position:0% +has a plus or minus is equal to zero for +our different from zero the formulas for + + align:start position:0% +our different from zero the formulas for + + + align:start position:0% +our different from zero the formulas for +the laplacian that you can use for are + + align:start position:0% +the laplacian that you can use for are + + + align:start position:0% +the laplacian that you can use for are +different from zero you can check that + + align:start position:0% +different from zero you can check that + + + align:start position:0% +different from zero you can check that +is true it's easy you can use that + + align:start position:0% +is true it's easy you can use that + + + align:start position:0% +is true it's easy you can use that +formula for example that the laplacian + + align:start position:0% +formula for example that the laplacian + + + align:start position:0% +formula for example that the laplacian +is 1 over R the second should be partial + + align:start position:0% +is 1 over R the second should be partial + + + align:start position:0% +is 1 over R the second should be partial +this second the R squared R subside like + + align:start position:0% +this second the R squared R subside like + + + align:start position:0% +this second the R squared R subside like +that that formula in one 30 seconds you + + align:start position:0% +that that formula in one 30 seconds you + + + align:start position:0% +that that formula in one 30 seconds you +can see that that works for are + + align:start position:0% +can see that that works for are + + + align:start position:0% +can see that that works for are +different from zero but then there's + + align:start position:0% +different from zero but then there's + + + align:start position:0% +different from zero but then there's +also a formula that you know that + + align:start position:0% +also a formula that you know that + + + align:start position:0% +also a formula that you know that +laplacian of 1 over R from + + align:start position:0% +laplacian of 1 over R from + + + align:start position:0% +laplacian of 1 over R from +electromagnetism is minus 4pi times the + + align:start position:0% +electromagnetism is minus 4pi times the + + + align:start position:0% +electromagnetism is minus 4pi times the +delta function of r this comes from + + align:start position:0% +delta function of r this comes from + + + align:start position:0% +delta function of r this comes from +poissons equation in electromagnetism so + + align:start position:0% +poissons equation in electromagnetism so + + + align:start position:0% +poissons equation in electromagnetism so +that's saying of laplacian of the + + align:start position:0% +that's saying of laplacian of the + + + align:start position:0% +that's saying of laplacian of the +potential is the charge density is the + + align:start position:0% +potential is the charge density is the + + + align:start position:0% +potential is the charge density is the +potential for a charge the charges at R + + align:start position:0% +potential for a charge the charges at R + + + align:start position:0% +potential for a charge the charges at R +equals 0 is a singularity it's something + + align:start position:0% +equals 0 is a singularity it's something + + + align:start position:0% +equals 0 is a singularity it's something +you study so here if I put a minus 1 + + align:start position:0% +you study so here if I put a minus 1 + + + align:start position:0% +you study so here if I put a minus 1 +over 4 PI 4G plus minus a minus 1 over 4 + + align:start position:0% +over 4 PI 4G plus minus a minus 1 over 4 + + + align:start position:0% +over 4 PI 4G plus minus a minus 1 over 4 +pi the laplacian of this whole thing is + + align:start position:0% +pi the laplacian of this whole thing is + + + align:start position:0% +pi the laplacian of this whole thing is +zero but when you approach zero the + + align:start position:0% +zero but when you approach zero the + + + align:start position:0% +zero but when you approach zero the +laplacian of this function this function + + align:start position:0% +laplacian of this function this function + + + align:start position:0% +laplacian of this function this function +approaches just 1 over R as R goes to 0 + + align:start position:0% +approaches just 1 over R as R goes to 0 + + + align:start position:0% +approaches just 1 over R as R goes to 0 +this goes to 1 and the laplacian of 1 + + align:start position:0% +this goes to 1 and the laplacian of 1 + + + align:start position:0% +this goes to 1 and the laplacian of 1 +over r gives you this minus 4 pi cancels + + align:start position:0% +over r gives you this minus 4 pi cancels + + + align:start position:0% +over r gives you this minus 4 pi cancels +with that and it will give you a delta + + align:start position:0% +with that and it will give you a delta + + + align:start position:0% +with that and it will give you a delta +function so the delta function will + + align:start position:0% +function so the delta function will + + + align:start position:0% +function so the delta function will +arise correctly from this quantity so + + align:start position:0% +arise correctly from this quantity so + + + align:start position:0% +arise correctly from this quantity so +i've argued without solving this + + align:start position:0% +i've argued without solving this + + + align:start position:0% +i've argued without solving this +equation that this does give you a + + align:start position:0% +equation that this does give you a + + + align:start position:0% +equation that this does give you a +solution of the greens for the greens + + align:start position:0% +solution of the greens for the greens + + + align:start position:0% +solution of the greens for the greens +function its laplacian plus K squared is + + align:start position:0% +function its laplacian plus K squared is + + + align:start position:0% +function its laplacian plus K squared is +0 away from 0 and as you approach 0 it + + align:start position:0% +0 away from 0 and as you approach 0 it + + + align:start position:0% +0 away from 0 and as you approach 0 it +has a bright singularity to give a delta + + align:start position:0% +has a bright singularity to give a delta + + + align:start position:0% +has a bright singularity to give a delta +function so this is your greens function + + align:start position:0% +function so this is your greens function + + + align:start position:0% +function so this is your greens function +as I said many ways to derive it if you + + align:start position:0% +as I said many ways to derive it if you + + + align:start position:0% +as I said many ways to derive it if you +want see griffiths see other ways in + + align:start position:0% +want see griffiths see other ways in + + + align:start position:0% +want see griffiths see other ways in +which it can be done then you can also + + align:start position:0% +which it can be done then you can also + + + align:start position:0% +which it can be done then you can also +check this by doing properly the vector + + align:start position:0% +check this by doing properly the vector + + + align:start position:0% +check this by doing properly the vector +calculus you can take a laplacian as + + align:start position:0% +calculus you can take a laplacian as + + + align:start position:0% +calculus you can take a laplacian as +divergence of the gradient and calculate + + align:start position:0% +divergence of the gradient and calculate + + + align:start position:0% +divergence of the gradient and calculate +every step and it's it's fun to do it as + + align:start position:0% +every step and it's it's fun to do it as + + + align:start position:0% +every step and it's it's fun to do it as +well you check that this works oh this + + align:start position:0% +well you check that this works oh this + + + align:start position:0% +well you check that this works oh this +works + + align:start position:0% +works + + + align:start position:0% +works +and now we have to make choices and our + + align:start position:0% +and now we have to make choices and our + + + align:start position:0% +and now we have to make choices and our +choices are going to be adjusted to the + + align:start position:0% +choices are going to be adjusted to the + + + align:start position:0% +choices are going to be adjusted to the +problem we're trying to solve we're + + align:start position:0% +problem we're trying to solve we're + + + align:start position:0% +problem we're trying to solve we're +trying to solve a scattering problem and + + align:start position:0% +trying to solve a scattering problem and + + + align:start position:0% +trying to solve a scattering problem and +sighs zero represents a solution and + + align:start position:0% +sighs zero represents a solution and + + + align:start position:0% +sighs zero represents a solution and +from the way we thought of our waves we + + align:start position:0% +from the way we thought of our waves we + + + align:start position:0% +from the way we thought of our waves we +had sigh we'll eat to the I KZ plus F of + + align:start position:0% +had sigh we'll eat to the I KZ plus F of + + + align:start position:0% +had sigh we'll eat to the I KZ plus F of +theta and Phi e to the IKr over R so + + align:start position:0% +theta and Phi e to the IKr over R so + + + align:start position:0% +theta and Phi e to the IKr over R so +it's reasonable to try to set and we're + + align:start position:0% +it's reasonable to try to set and we're + + + align:start position:0% +it's reasonable to try to set and we're +going to find solutions by serving size + + align:start position:0% +going to find solutions by serving size + + + align:start position:0% +going to find solutions by serving size +zero to be e to the i kz it does solve + + align:start position:0% +zero to be e to the i kz it does solve + + + align:start position:0% +zero to be e to the i kz it does solve +the equation laplacian square plus K + + align:start position:0% +the equation laplacian square plus K + + + align:start position:0% +the equation laplacian square plus K +squared equals zero and then we're going + + align:start position:0% +squared equals zero and then we're going + + + align:start position:0% +squared equals zero and then we're going +to set the greens function to be G plus + + align:start position:0% +to set the greens function to be G plus + + + align:start position:0% +to set the greens function to be G plus +with a plus here because we want + + align:start position:0% +with a plus here because we want + + + align:start position:0% +with a plus here because we want +solutions of the type e to the IKr we've + + align:start position:0% +solutions of the type e to the IKr we've + + + align:start position:0% +solutions of the type e to the IKr we've +already decided those were the solutions + + align:start position:0% +already decided those were the solutions + + + align:start position:0% +already decided those were the solutions +we need and a greens function with a + + align:start position:0% +we need and a greens function with a + + + align:start position:0% +we need and a greens function with a +plus in there it's gonna generate that + + align:start position:0% +plus in there it's gonna generate that + + + align:start position:0% +plus in there it's gonna generate that +so those are fine you could have chosen + + align:start position:0% +so those are fine you could have chosen + + + align:start position:0% +so those are fine you could have chosen +another thing here an arbitrary solution + + align:start position:0% +another thing here an arbitrary solution + + + align:start position:0% +another thing here an arbitrary solution +and you could have chosen and G minus as + + align:start position:0% +and you could have chosen and G minus as + + + align:start position:0% +and you could have chosen and G minus as +well and you would get a solution of the + + align:start position:0% +well and you would get a solution of the + + + align:start position:0% +well and you would get a solution of the +Schrodinger equation it would not have + + align:start position:0% +Schrodinger equation it would not have + + + align:start position:0% +Schrodinger equation it would not have +much to do with a solution we're trying + + align:start position:0% +much to do with a solution we're trying + + + align:start position:0% +much to do with a solution we're trying +to get so let's show that this gives us + + align:start position:0% +to get so let's show that this gives us + + + align:start position:0% +to get so let's show that this gives us +this kind of solution we want to get and + + align:start position:0% +this kind of solution we want to get and + + + align:start position:0% +this kind of solution we want to get and +gives us already a formula for the + + align:start position:0% +gives us already a formula for the + + + align:start position:0% +gives us already a formula for the +scattering amplitude so let's let's do + + align:start position:0% +scattering amplitude so let's let's do + + + align:start position:0% +scattering amplitude so let's let's do +that for that we just need to write what + + align:start position:0% +that for that we just need to write what + + + align:start position:0% +that for that we just need to write what +the greens function is and approximate + + align:start position:0% + + + + align:start position:0% + +so it will be a first step okay so what + + align:start position:0% +so it will be a first step okay so what + + + align:start position:0% +so it will be a first step okay so what +do we have + + align:start position:0% +do we have + + + align:start position:0% +do we have +sigh of our is equal to e to the i ka + + align:start position:0% +sigh of our is equal to e to the i ka + + + align:start position:0% +sigh of our is equal to e to the i ka +I'm writing up this top equation but we + + align:start position:0% +I'm writing up this top equation but we + + + align:start position:0% +I'm writing up this top equation but we +now write it with the right boundary + + align:start position:0% +now write it with the right boundary + + + align:start position:0% +now write it with the right boundary +conditions which correspond to upsize + + align:start position:0% +conditions which correspond to upsize + + + align:start position:0% +conditions which correspond to upsize +zero and a particularly greens function + + align:start position:0% +zero and a particularly greens function + + + align:start position:0% +zero and a particularly greens function +the cube are prime G of R minus R prime + + align:start position:0% +the cube are prime G of R minus R prime + + + align:start position:0% +the cube are prime G of R minus R prime +u of our prime all those are vectors and + + align:start position:0% +u of our prime all those are vectors and + + + align:start position:0% +u of our prime all those are vectors and +sy of our prime all those are vectors + + align:start position:0% +sy of our prime all those are vectors + + + align:start position:0% +sy of our prime all those are vectors +except G which is pretty in that it is + + align:start position:0% +except G which is pretty in that it is + + + align:start position:0% +except G which is pretty in that it is +spherically symmetric this G plus minus + + align:start position:0% +spherically symmetric this G plus minus + + + align:start position:0% +spherically symmetric this G plus minus +of our just depends on the magnitude of + + align:start position:0% +of our just depends on the magnitude of + + + align:start position:0% +of our just depends on the magnitude of +R which is very nice okay so a couple of + + align:start position:0% +R which is very nice okay so a couple of + + + align:start position:0% +R which is very nice okay so a couple of +things that we can do here and most + + align:start position:0% +things that we can do here and most + + + align:start position:0% +things that we can do here and most +everybody would do let's G plus of R + + align:start position:0% +everybody would do let's G plus of R + + + align:start position:0% +everybody would do let's G plus of R +minus R prime is equal to minus 1 over 4 + + align:start position:0% +minus R prime is equal to minus 1 over 4 + + + align:start position:0% +minus R prime is equal to minus 1 over 4 +pi e to the I K length of our minus R + + align:start position:0% +pi e to the I K length of our minus R + + + align:start position:0% +pi e to the I K length of our minus R +prime that's what this is supposed to be + + align:start position:0% +prime that's what this is supposed to be + + + align:start position:0% +prime that's what this is supposed to be +over length of our minus R prime + + align:start position:0% +over length of our minus R prime + + + align:start position:0% +over length of our minus R prime +remember I said to you that whenever we + + align:start position:0% +remember I said to you that whenever we + + + align:start position:0% +remember I said to you that whenever we +had G of r then to get the one we need + + align:start position:0% +had G of r then to get the one we need + + + align:start position:0% +had G of r then to get the one we need +we'll just have to replace the r by r + + align:start position:0% +we'll just have to replace the r by r + + + align:start position:0% +we'll just have to replace the r by r +minus r prime and here this little r or + + align:start position:0% +minus r prime and here this little r or + + + align:start position:0% +minus r prime and here this little r or +r without the vector is the magnitude of + + align:start position:0% +r without the vector is the magnitude of + + + align:start position:0% +r without the vector is the magnitude of +this vector so we've put the magnitude + + align:start position:0% +this vector so we've put the magnitude + + + align:start position:0% +this vector so we've put the magnitude +of those vectors there now people look + + align:start position:0% +of those vectors there now people look + + + align:start position:0% +of those vectors there now people look +for approximations in here so here is + + align:start position:0% +for approximations in here so here is + + + align:start position:0% +for approximations in here so here is +what we need to do imagine you are the + + align:start position:0% +what we need to do imagine you are the + + + align:start position:0% +what we need to do imagine you are the +origin here is a potential and you have + + align:start position:0% +origin here is a potential and you have + + + align:start position:0% +origin here is a potential and you have +your system of coordinates you are + + align:start position:0% +your system of coordinates you are + + + align:start position:0% +your system of coordinates you are +integrating + + align:start position:0% + + + + align:start position:0% + +over places where the potential exists + + align:start position:0% +over places where the potential exists + + + align:start position:0% +over places where the potential exists +so the r-prime that you're integrating + + align:start position:0% +so the r-prime that you're integrating + + + align:start position:0% +so the r-prime that you're integrating +remains inside the range of the + + align:start position:0% +remains inside the range of the + + + align:start position:0% +remains inside the range of the +potential here is zero and then there's + + align:start position:0% +potential here is zero and then there's + + + align:start position:0% +potential here is zero and then there's +an R which is where you are looking at + + align:start position:0% +an R which is where you are looking at + + + align:start position:0% +an R which is where you are looking at +and there's an angle between these two + + align:start position:0% +and there's an angle between these two + + + align:start position:0% +and there's an angle between these two +maybe I should I mean make the angle a + + align:start position:0% +maybe I should I mean make the angle a + + + align:start position:0% +maybe I should I mean make the angle a +little bigger smaller I mean R and if in + + align:start position:0% +little bigger smaller I mean R and if in + + + align:start position:0% +little bigger smaller I mean R and if in +general we look always far enough this + + align:start position:0% +general we look always far enough this + + + align:start position:0% +general we look always far enough this +is an exact solution but we might as + + align:start position:0% +is an exact solution but we might as + + + align:start position:0% +is an exact solution but we might as +well considering consider looking at + + align:start position:0% +well considering consider looking at + + + align:start position:0% +well considering consider looking at +size that are located far from the + + align:start position:0% +size that are located far from the + + + align:start position:0% +size that are located far from the +potential so we have the idea of what + + align:start position:0% +potential so we have the idea of what + + + align:start position:0% +potential so we have the idea of what +should we do with this terms one thing + + align:start position:0% +should we do with this terms one thing + + + align:start position:0% +should we do with this terms one thing +you can do is to say that in the + + align:start position:0% +you can do is to say that in the + + + align:start position:0% +you can do is to say that in the +denominator here R minus R prime is good + + align:start position:0% +denominator here R minus R prime is good + + + align:start position:0% +denominator here R minus R prime is good +enough to set it to R in the denominator + + align:start position:0% + + + + align:start position:0% + +and for the numerator however it's a lot + + align:start position:0% +and for the numerator however it's a lot + + + align:start position:0% +and for the numerator however it's a lot +more sensitive because you have a K here + + align:start position:0% +more sensitive because you have a K here + + + align:start position:0% +more sensitive because you have a K here +and depending on whether K is large or + + align:start position:0% +and depending on whether K is large or + + + align:start position:0% +and depending on whether K is large or +small that small difference in our minus + + align:start position:0% +small that small difference in our minus + + + align:start position:0% +small that small difference in our minus +R prime if you're estimating this and + + align:start position:0% +R prime if you're estimating this and + + + align:start position:0% +R prime if you're estimating this and +you make an error comparable with the + + align:start position:0% +you make an error comparable with the + + + align:start position:0% +you make an error comparable with the +wavelength of your particle you make a + + align:start position:0% +wavelength of your particle you make a + + + align:start position:0% +wavelength of your particle you make a +big mistake if you're far away you're a + + align:start position:0% +big mistake if you're far away you're a + + + align:start position:0% +big mistake if you're far away you're a +hundred times farther than the range of + + align:start position:0% +hundred times farther than the range of + + + align:start position:0% +hundred times farther than the range of +the potential here you're making a 1 + + align:start position:0% +the potential here you're making a 1 + + + align:start position:0% +the potential here you're making a 1 +percent error no problem but if you're + + align:start position:0% +percent error no problem but if you're + + + align:start position:0% +percent error no problem but if you're +making a 1 percent error in the estimate + + align:start position:0% +making a 1 percent error in the estimate + + + align:start position:0% +making a 1 percent error in the estimate +of this that might be still comparable + + align:start position:0% +of this that might be still comparable + + + align:start position:0% +of this that might be still comparable +to the wavelength of this K so you have + + align:start position:0% +to the wavelength of this K so you have + + + align:start position:0% +to the wavelength of this K so you have +to be a lot more careful in the face + + align:start position:0% +to be a lot more careful in the face + + + align:start position:0% +to be a lot more careful in the face +than you have to be on the other one so + + align:start position:0% +than you have to be on the other one so + + + align:start position:0% +than you have to be on the other one so +on the face for the number for the face + + align:start position:0% +on the face for the number for the face + + + align:start position:0% +on the face for the number for the face +face + + align:start position:0% +face + + + align:start position:0% +face +we will take our - our prime equal to R + + align:start position:0% +we will take our - our prime equal to R + + + align:start position:0% +we will take our - our prime equal to R +minus n R Prime + + align:start position:0% +minus n R Prime + + + align:start position:0% +minus n R Prime +so what is n n is a unit vector in this + + align:start position:0% +so what is n n is a unit vector in this + + + align:start position:0% +so what is n n is a unit vector in this +direction and indeed approximately the + + align:start position:0% +direction and indeed approximately the + + + align:start position:0% +direction and indeed approximately the +this distance here is approximately + + align:start position:0% +this distance here is approximately + + + align:start position:0% +this distance here is approximately +equal to the distance R minus the + + align:start position:0% +equal to the distance R minus the + + + align:start position:0% +equal to the distance R minus the +projection of our prime into this one so + + align:start position:0% +projection of our prime into this one so + + + align:start position:0% +projection of our prime into this one so +that is your approximate distance so + + align:start position:0% +that is your approximate distance so + + + align:start position:0% +that is your approximate distance so +here is the final formula we're gonna + + align:start position:0% +here is the final formula we're gonna + + + align:start position:0% +here is the final formula we're gonna +write today I'm running out of time + + align:start position:0% +write today I'm running out of time + + + align:start position:0% +write today I'm running out of time +but that's what we wanted to end up with + + align:start position:0% +but that's what we wanted to end up with + + + align:start position:0% +but that's what we wanted to end up with +so here is what we get so g + of R minus + + align:start position:0% +so here is what we get so g + of R minus + + + align:start position:0% +so here is what we get so g + of R minus +R prime has become minus 1 over 4 PI R + + align:start position:0% +R prime has become minus 1 over 4 PI R + + + align:start position:0% +R prime has become minus 1 over 4 PI R +the denominator is R there's an e to the + + align:start position:0% +the denominator is R there's an e to the + + + align:start position:0% +the denominator is R there's an e to the +IKr and then e to the minus I K and R + + align:start position:0% +IKr and then e to the minus I K and R + + + align:start position:0% +IKr and then e to the minus I K and R +Prime so that's and the arrows are + + align:start position:0% +Prime so that's and the arrows are + + + align:start position:0% +Prime so that's and the arrows are +crucial here if I don't put an arrow + + align:start position:0% +crucial here if I don't put an arrow + + + align:start position:0% +crucial here if I don't put an arrow +somewhere it probably means something so + + align:start position:0% +somewhere it probably means something so + + + align:start position:0% +somewhere it probably means something so +I of R is equal to e to the i kz + minus + + align:start position:0% +I of R is equal to e to the i kz + minus + + + align:start position:0% +I of R is equal to e to the i kz + minus +1 over 4 pi r the integral over R prime + + align:start position:0% +1 over 4 pi r the integral over R prime + + + align:start position:0% +1 over 4 pi r the integral over R prime +doesn't care about this the cube R prime + + align:start position:0% +doesn't care about this the cube R prime + + + align:start position:0% +doesn't care about this the cube R prime +e to the minus I K and dot R prime times + + align:start position:0% +e to the minus I K and dot R prime times + + + align:start position:0% +e to the minus I K and dot R prime times +U of our prime of CI of our prime all + + align:start position:0% +U of our prime of CI of our prime all + + + align:start position:0% +U of our prime of CI of our prime all +that x let me take the our out into the + + align:start position:0% +that x let me take the our out into the + + + align:start position:0% +that x let me take the our out into the +I K R over + + align:start position:0% +I K R over + + + align:start position:0% +I K R over +are so look at what we've obtained I + + align:start position:0% +are so look at what we've obtained I + + + align:start position:0% +are so look at what we've obtained I +just rewrote finally this expression for + + align:start position:0% +just rewrote finally this expression for + + + align:start position:0% +just rewrote finally this expression for +the greens function over there with the + + align:start position:0% +the greens function over there with the + + + align:start position:0% +the greens function over there with the +integral over our prime and the greens + + align:start position:0% +integral over our prime and the greens + + + align:start position:0% +integral over our prime and the greens +function here you have this quantity in + + align:start position:0% +function here you have this quantity in + + + align:start position:0% +function here you have this quantity in +brackets this quantity in brackets here + + align:start position:0% +brackets this quantity in brackets here + + + align:start position:0% +brackets this quantity in brackets here +is nothing but the F of theta phi of the + + align:start position:0% +is nothing but the F of theta phi of the + + + align:start position:0% +is nothing but the F of theta phi of the +scattering amplitude you have this equal + + align:start position:0% +scattering amplitude you have this equal + + + align:start position:0% +scattering amplitude you have this equal +to that plus e to the IKr over R so + + align:start position:0% +to that plus e to the IKr over R so + + + align:start position:0% +to that plus e to the IKr over R so +we'll continue that next time and finish + + align:start position:0% +we'll continue that next time and finish + + + align:start position:0% +we'll continue that next time and finish +up with scattering crowding the first + + align:start position:0% +up with scattering crowding the first + + + align:start position:0% +up with scattering crowding the first +half of the next lecture \ No newline at end of file diff --git a/2Op3QLzMgSY.txt b/2Op3QLzMgSY.txt new file mode 100644 index 0000000000000000000000000000000000000000..2d063943a275ceb338ca889abcdc5f582de49e34 --- /dev/null +++ b/2Op3QLzMgSY.txt @@ -0,0 +1,3219 @@ +[MUSIC PLAYING] + +PROFESSOR: I'd like to +welcome you to this + +course on computer science. + +Actually, that's a terrible +way to start. + +Computer science is a terrible +name for this business. + +First of all, it's +not a science. + +It might be engineering or it +might be art, but we'll + +actually see that computer +so-called science actually has + +a lot in common with magic, +and we'll see + +that in this course. + +So it's not a science. + +It's also not really very +much about computers. + +And it's not about computers in +the same sense that physics + +is not really about particle +accelerators, and biology is + +not really about microscopes +and petri dishes. + +And it's not about computers +in the same sense that + +geometry is not really about +using surveying instruments. + +In fact, there's a lot of +commonality between computer + +science and geometry. + +Geometry, first of all, +is another subject + +with a lousy name. + +The name comes from Gaia, +meaning the Earth, and metron, + +meaning to measure. + +Geometry originally +meant measuring + +the Earth or surveying. + +And the reason for that was +that, thousands of years ago, + +the Egyptian priesthood +developed the rudiments of + +geometry in order to figure +out how to restore the + +boundaries of fields that were +destroyed in the annual + +flooding of the Nile. + +And to the Egyptians who did +that, geometry really was the + +use of surveying instruments. + +Now, the reason that we think +computer science is about + +computers is pretty much the +same reason that the Egyptians + +thought geometry was about +surveying instruments. + +And that is, when some field +is just getting started and + +you don't really understand it +very well, it's very easy to + +confuse the essence of what +you're doing with the tools + +that you use. + +And indeed, on some absolute +scale of things, we probably + +know less about the essence of +computer science than the + +ancient Egyptians really +knew about geometry. + +Well, what do I mean by the +essence of computer science? + +What do I mean by the +essence of geometry? + +See, it's certainly true that +these Egyptians went off and + +used surveying instruments, but +when we look back on them + +after a couple of thousand +years, we say, gee, what they + +were doing, the important stuff +they were doing, was to + +begin to formalize notions about +space and time, to start + +a way of talking about +mathematical truths formally. + +That led to the axiomatic +method. + +That led to sort of all of +modern mathematics, figuring + +out a way to talk precisely +about so-called declarative + +knowledge, what is true. + +Well, similarly, I think in the +future people will look + +back and say, yes, those +primitives in the 20th century + +were fiddling around with +these gadgets called + +computers, but really what they +were doing is starting to + +learn how to formalize +intuitions about process, how + +to do things, starting to +develop a way to talk + +precisely about how-to +knowledge, as opposed to + +geometry that talks about +what is true. + +Let me give you an +example of that. + +Let's take a look. + +Here is a piece of mathematics +that says what + +a square root is. + +The square root of X is the +number Y, such that Y squared + +is equal to X and Y +is greater than 0. + +Now, that's a fine piece of +mathematics, but just telling + +you what a square root is +doesn't really say anything + +about how you might go +out and find one. + +So let's contrast that with a +piece of imperative knowledge, + +how you might go out and +find a square root. + +This, in fact, also comes +from Egypt, not + +ancient, ancient Egypt. + +This is an algorithm due to +Heron of Alexandria, called + +how to find a square root +by successive averaging. + +And what it says is that, in +order to find a square root, + +you make a guess, you +improve that guess-- + +and the way you improve the +guess is to average the guess + +and X over the guess, and we'll +talk a little bit later + +about why that's a reasonable +thing-- + +and you keep improving the guess +until it's good enough. + +That's a method. + +That's how to do something +as opposed to declarative + +knowledge that says what +you're looking for. + +That's a process. + +Well, what's a process +in general? + +It's kind of hard to say. + +You can think of it as like a +magical spirit that sort of + +lives in the computer +and does something. + +And the thing that directs a +process is a pattern of rules + +called a procedure. + +So procedures are the spells, +if you like, that control + +these magical spirits that +are the processes. + +I guess you know everyone needs +a magical language, and + +sorcerers, real sorcerers, use +ancient Arcadian or Sumerian + +or Babylonian or whatever. + +We're going to conjure our +spirits in a magical language + +called Lisp, which is a language +designed for talking + +about, for casting the spells +that are procedures to direct + +the processes. + +Now, it's very easy +to learn Lisp. + +In fact, in a few minutes, +I'm going to teach you, + +essentially, all of Lisp. + +I'm going to teach you, +essentially, all of the rules. + +And you shouldn't find that +particularly surprising. + +That's sort of like saying it's +very easy to learn the + +rules of chess. + +And indeed, in a few minutes, +you can tell somebody the + +rules of chess. + +But of course, that's very +different from saying you + +understand the implications of +those rules and how to use + +those rules to become a +masterful chess player. + +Well, Lisp is the same way. + +We're going to state the rules +in a few minutes, and it'll be + +very easy to see. + +But what's really hard is going +to be the implications + +of those rules, how you exploit +those rules to be a + +master programmer. + +And the implications of those +rules are going to take us + +the, well, the whole rest of +the subject and, of course, + +way beyond. + +OK, so in computer science, +we're in the business of + +formalizing this sort of how-to +imperative knowledge, + +how to do stuff. + +And the real issues of computer +science are, of + +course, not telling people +how to do square roots. + +Because if that was +all it was, there + +wouldn't be no big deal. + +The real problems come when we +try to build very, very large + +systems, computer programs that +are thousands of pages + +long, so long that nobody can +really hold them in their + +heads all at once. + +And the only reason that that's +possible is because + +there are techniques for +controlling the complexity of + +these large systems. And these +techniques that are + +controlling complexity +are what this + +course is really about. + +And in some sense, that's +really what + +computer science is about. + +Now, that may seem like a very +strange thing to say. + +Because after all, a lot of +people besides computer + +scientists deal with controlling +complexity. + +A large airliner is an extremely +complex system, and + +the aeronautical engineers who +design that are dealing with + +immense complexity. + +But there's a difference +between that kind of + +complexity and what we deal +with in computer science. + +And that is that computer +science, in some + +sense, isn't real. + +You see, when an engineer is +designing a physical system, + +that's made out of real parts. + +The engineers who worry about +that have to address problems + +of tolerance and approximation +and noise in the system. + +So for example, as an electrical +engineer, I can go + +off and easily build a one-stage +amplifier or a + +two-stage amplifier, and I can +imagine cascading a lot of + +them to build a million-stage +amplifier. + +But it's ridiculous to build +such a thing, because long + +before the millionth stage, +the thermal noise in those + +components way at the beginning +is going to get + +amplified and make the whole +thing meaningless. + +Computer science deals with +idealized components. + +We know as much as we want about +these little program and + +data pieces that we're fitting +things together. + +We don't have to worry +about tolerance. + +And that means that, in building +a large program, + +there's not all that much +difference between what I can + +build and what I can imagine, +because the parts are these + +abstract entities that I +know as much as I want. + +I know about them as precisely +as I'd like. + +So as opposed to other kinds +of engineering, where the + +constraints on what you can +build are the constraints of + +physical systems, the +constraints of physics and + +noise and approximation, the +constraints imposed in + +building large software systems +are the limitations of + +our own minds. + +So in that sense, computer +science is like an abstract + +form of engineering. + +It's the kind of engineering +where you ignore the + +constraints that are +imposed by reality. + +Well, what are some of +these techniques? + +They're not special to +computer science. + +First technique, which is used +in all of engineering, is a + +kind of abstraction called +black-box abstraction. + +Take something and build +a box about it. + +Let's see, for example, if we +looked at that square root + +method, I might want to take +that and build a box. + +That sort of says, to find the +square root of X. And that + +might be a whole complicated +set of rules. + +And that might end up being a +kind of thing where I can put + +in, say, 36 and say, what's +the square root of 36? + +And out comes six. + +And the important thing is that +I'd like to design that + +so that if George comes along +and would like to compute, + +say, the square root of A plus +the square root of B, he can + +take this thing and use it as +a module without having to + +look inside and build something +that looks like + +this, like an A and a B and a +square root box and another + +square root box and then +something that adds that would + +put out the answer. + +And you can see, just from the +fact that I want to do that, + +is from George's point of view, +the internals of what's + +in here should not +be important. + +So for instance, it shouldn't +matter that, when I wrote + +this, I said I want to find the +square root of X. I could + +have said the square root of Y, +or the square root of A, or + +anything at all. + +That's the fundamental notion of +putting something in a box + +using black-box abstraction +to suppress detail. + +And the reason for that is you +want to go off and build + +bigger boxes. + +Now, there's another reason +for doing black-box + +abstraction other than you want +to suppress detail for + +building bigger boxes. + +Sometimes you want to say that +your way of doing something, + +your how-to method, is an +instance of a more general + +thing, and you'd like your +language to be able to express + +that generality. + +Let me show you another example + +sticking with square roots. + +Let's go back and take another +look at that slide with the + +square root algorithm on it. + +Remember what that says. + +That says, in order to do +something, I make a guess, and + +I improve that guess, +and I sort of keep + +improving that guess. + +So there's the general strategy +of, I'm looking for + +something, and the way +I find it is that I + +keep improving it. + +Now, that's a particular case +of another kind of strategy + +for finding a fixed point +of something. + +So you have a fixed point +of a function. + +A fixed point of a function +is something, is a value. + +A fixed point of a function F is +a value Y, such that F of Y + +equals Y. And the way I might do +that is start with a guess. + +And then if I want something +that doesn't change when I + +keep applying F, is I'll keep +applying F over and over until + +that result doesn't +change very much. + +So there's a general strategy. + +And then, for example, to +compute the square root of X, + +I can try and find a fixed point +of the function which + +takes Y to the average of X/Y. +And the idea that is that if I + +really had Y equal to the square +root of X, then Y and + +X/Y would be the same value. + +They'd both be the square root +of X, because X over the + +square root of X is the +square root of X. + +And so the average if Y were +equal to the square of X, then + +the average wouldn't change. + +So the square root of X +is a fixed point of + +that particular function. + +Now, what I'd like to have, +I'd like to express the + +general strategy for finding +fixed points. + +So what I might imagine doing, +is to find, is to be able to + +use my language to define a box +that says "fixed point," + +just like I could make a box +that says "square root." And + +I'd like to be able to express +this in my language. + +So I'd like to express not only +the imperative how-to + +knowledge of a particular thing +like square root, but + +I'd like to be able to express +the imperative knowledge of + +how to do a general thing like +how to find fixed point. + +And in fact, let's go back and +look at that slide again. + +See, not only is this a piece +of imperative knowledge, how + +to find a fixed point, but +over here on the bottom, + +there's another piece of +imperative knowledge which + +says, one way to compute square +root is to apply this + +general fixed point method. + +So I'd like to also +be able to express + +that imperative knowledge. + +What would that look like? + +That would say, this fixed point +box is such that if I + +input to it the function that +takes Y to the average of Y + +and X/Y, then what should come +out of that fixed point box is + +a method for finding +square roots. + +So in these boxes we're +building, we're not only + +building boxes that you input +numbers and output numbers, + +we're going to be building in +boxes that, in effect, compute + +methods like finding +square root. + +And my take is their inputs +functions, like Y goes to the + +average of Y and X/Y. The reason +we want to do that, the + +reason this is a procedure, will +end up being a procedure, + +as we'll see, whose value is +another procedure, the reason + +we want to do that is because +procedures are going to be our + +ways of talking about imperative +knowledge. + +And the way to make that very +powerful is to be able to talk + +about other kinds +of knowledge. + +So here is a procedure that, in +effect, talks about another + +procedure, a general strategy +that itself talks about + +general strategies. + +Well, our first topic in this +course-- there'll be three + +major topics-- will be black-box +abstraction. + +Let's look at that in a little +bit more detail. + +What we're going to do is we +will start out talking about + +how Lisp is built up out +of primitive objects. + +What does the language +supply with us? + +And we'll see that there are +primitive procedures and + +primitive data. + +Then we're going to see, how do +you take those primitives + +and combine them to make more +complicated things, means of + +combination? + +And what we'll see is that +there are ways of putting + +things together, putting +primitive procedures together + +to make more complicated +procedures. + +And we'll see how to put +primitive data together to + +make compound data. + +Then we'll say, well, having +made those compounds things, + +how do you abstract them? + +How do you put those black boxes +around them so you can + +use them as components in +more complex things? + +And we'll see that's done by +defining procedures and a + +technique for dealing with +compound data called data + +abstraction. + +And then, what's maybe the most +important thing, is going + +from just the rules to how +does an expert work? + +How do you express common +patterns of doing things, like + +saying, well, there's a general +method of fixed point + +and square root is a particular +case of that? + +And we're going to use-- + +I've already hinted at it-- +something called higher-order + +procedures, namely procedures +whose inputs and outputs are + +themselves procedures. + +And then we'll also see +something very interesting. + +We'll see, as we go further and +further on and become more + +abstract, there'll be very-- + +well, the line between what we +consider to be data and what + +we consider to be procedures +is going to blur at an + +incredible rate. + +Well, that's our first +subject, black-box + +abstraction. + +Let's look at the +second topic. + +I can introduce it like this. + +See, suppose I want to +express the idea-- + +remember, we're talking +about ideas-- + +suppose I want to express the +idea that I can take something + +and multiply it by the sum +of two other things. + +So for example, I might say, +if I had one and three and + +multiply that by two, +I get eight. + +But I'm talking about the +general idea of what's called + +linear combination, that you +can add two things and + +multiply them by +something else. + +It's very easy when I think +about it for numbers, but + +suppose I also want to use that +same idea to think about, + +I could add two vectors, a1 and +a2, and then scale them by + +some factor x and get +another vector. + +Or I might say, I want to think +about a1 and a2 as being + +polynomials, and I might want +to add those two polynomials + +and then multiply them by two to +get a more complicated one. + +Or a1 and a2 might be electrical +signals, and I + +might want to think about +summing those two electrical + +signals and then putting the +whole thing through an + +amplifier, multiplying +it by some + +factor of two or something. + +The idea is I want to +think about the + +general notion of that. + +Now, if our language is going +to be good language for + +expressing those kind of general +ideas, if I really, + +really can do that, I'd like to +be able to say I'm going to + +multiply by x the sum of a1 and +a2, and I'd like that to + +express the general idea of all +different kinds of things + +that a1 and a2 could be. + +Now, if you think about that, +there's a problem, because + +after all, the actual primitive +operations that go + +on in the machine are obviously +going to be + +different if I'm adding two +numbers than if I'm adding two + +polynomials, or if I'm adding +the representation of two + +electrical signals +or wave forms. + +Somewhere, there has to be the +knowledge of the kinds of + +various things that you +can add and the + +ways of adding them. + +Now, to construct such a system, +the question is, where + +do I put that knowledge? + +How do I think about +the different kinds + +of choices I have? + +And if tomorrow George comes up +with a new kind of object + +that might be added and +multiplied, how do I add + +George's new object to the +system without screwing up + +everything that was +already there? + +Well, that's going to be the +second big topic, the way of + +controlling that kind +of complexity. + +And the way you do that is by +establishing conventional + +interfaces, agreed upon ways of +plugging things together. + +Just like in electrical +engineering, people have + +standard impedances for +connectors, and then you know + +if you build something with +one of those standard + +impedances, you can plug it +together with something else. + +So that's going to be our +second large topic, + +conventional interfaces. + +What we're going to see is, +first, we're going to talk + +about the problem of generic +operations, which is the one I + +alluded to, things like "plus" +that have to work with all + +different kinds of data. + +So we talk about generic +operations. + +Then we're going to talk about +really large-scale structures. + +How do you put together very +large programs that model the + +kinds of complex systems +in the real world that + +you'd like to model? + +And what we're going to see +is that there are two very + +important metaphors for putting +together such systems. + +One is called object-oriented +programming, where you sort of + +think of your system as a kind +of society full of little + +things that interact by sending + +information between them. + +And then the second one is +operations on aggregates, + +called streams, where you think +of a large system put + +together kind of like a signal +processing engineer puts + +together a large electrical +system. + +That's going to be +our second topic. + +Now, the third thing we're going +to come to, the third + +basic technique for controlling +complexity, is + +making new languages. + +Because sometimes, when you're +sort of overwhelmed by the + +complexity of a design, the +way that you control that + +complexity is to pick a +new design language. + +And the purpose of the new +design language will be to + +highlight different aspects +of the system. + +It will suppress some kinds of +details and emphasize other + +kinds of details. + +This is going to be the most +magical part of the course. + +We're going to start out by +actually looking at the + +technology for building new +computer languages. + +The first thing we're going to +do is actually build in Lisp. + +We're going to express in Lisp +the process of interpreting + +Lisp itself. + +And that's going to be a very +sort of self-circular thing. + +There's a little mystical +symbol that + +has to do with that. + +The process of interpreting Lisp +is sort of a giant wheel + +of two processes, apply and +eval, which sort of constantly + +reduce expressions +to each other. + +Then we're going to see all +sorts of other magical things. + +Here's another magical symbol. + +This is sort of the Y operator, +which is, in some + +sense, the expression +of infinity inside + +our procedural language. + +We'll take a look at that. + +In any case, this section +of the course is called + +Metalinguistic Abstraction, +abstracting by talking about + +how you construct +new languages. + +As I said, we're going to start +out by looking at the + +process of interpretation. + +We're going to look +at this apply-eval + +loop, and build Lisp. + +Then, just to show you that this +is very general, we're + +going to use exactly the same +technology to build a very + +different kind of language, a +so-called logic programming + +language, where you don't really +talk about procedures + +at all that have inputs +and outputs. + +What you do is talk about +relations between things. + +And then finally, we're going +to talk about how you + +implement these things very +concretely on the very + +simplest kind of machines. + +We'll see something like this. + +This is a picture of a chip, +which is the Lisp interpreter + +that we will be talking about +then in hardware. + +Well, there's an outline of the +course, three big topics. + +Black-box abstraction, +conventional interfaces, + +metalinguistic abstraction. + +Now, let's take a break now and +then we'll get started. + +[MUSIC PLAYING] + +Let's actually start in +learning Lisp now. + +Actually, we'll start out by +learning something much more + +important, maybe the very most +important thing in this + +course, which is not Lisp, in +particular, of course, but + +rather a general framework for +thinking about languages that + +I already alluded to. + +When somebody tells you they're +going to show you a + +language, what you should say +is, what I'd like you to tell + +me is what are the primitive +elements? + +What does the language +come with? + +Then, what are the ways you +put those together? + +What are the means +of combination? + +What are the things that allow +you to take these primitive + +elements and build bigger +things out of them? + +What are the ways of putting +things together? + +And then, what are the +means of abstraction? + +How do we take those complicated +things and draw + +those boxes around them? + +How do we name them so that we +can now use them as if they + +were primitive elements +in making still + +more complex things? + +And so on, and so +on, and so on. + +So when someone says to you, +gee, I have a great new + +computer language, you don't +say, how many characters does + +it take to invert a matrix? + +It's irrelevant. + +What you say is, if the language +did not come with + +matrices built in or with +something else built in, how + +could I then build that thing? + +What are the means of +combination which would allow + +me to do that? + +And then, what are the means of +abstraction which allow me + +then to use those as elements +in making more complicated + +things yet? + +Well, we're going to see that +Lisp has some primitive data + +and some primitive procedures. + +In fact, let's really start. + +And here's a piece of +primitive data in + +Lisp, number three. + +Actually, if I'm being very +pedantic, that's not the + +number three. + +That's some symbol that +represents Plato's concept of + +the number three. + +And here's another. + +Here's some more primitive +data in Lisp, 17.4. + +Or actually, some representation +of 17.4. + +And here's another one, five. + +Here's another primitive +object that's + +built in Lisp, addition. + +Actually, to use the same kind +of pedantic-- this is a name + +for the primitive method +of adding things. + +Just like this is a name for +Plato's number three, this is + +a name for Plato's concept +of how you add things. + +So those are some primitive +elements. + +I can put them together. + +I can say, gee, what's the sum +of three and 17.4 and five? + +And the way I do that is to +say, let's apply the sum + +operator to these +three numbers. + +And I should get, +what? eight, 17. + +25.4. + +So I should be able to ask Lisp +what the value of this + +is, and it will return 25.4. + +Let's introduce some names. + +This thing that I typed is +called a combination. + +And a combination consists, +in general, + +of applying an operator-- + +so this is an operator-- + +to some operands. + +These are the operands. + +And of course, I can make +more complex things. + +The reason I can get complexity +out of this is + +because the operands themselves, +in general, can be + +combinations. + +So for instance, I could say, +what is the sum of three and + +the product of five and +six and eight and two? + +And I should get-- let's see-- + +30, 40, 43. + +So Lisp should tell +me that that's 43. + +Forming combinations is the +basic needs of combination + +that we'll be looking at. + +And then, well, you see +some syntax here. + +Lisp uses what's called prefix +notation, which means that the + +operator is written to the +left of the operands. + +It's just a convention. + +And notice, it's fully +parenthesized. + +And the parentheses make it +completely unambiguous. + +So by looking at this, I can see +that there's the operator, + +and there are one, two, +three, four operands. + +And I can see that the second +operand here is itself some + +combination that has one +operator and two operands. + +Parentheses in Lisp are a little +bit, or are very unlike + +parentheses in conventional +mathematics. + +In mathematics, we sort of use +them to mean grouping, and it + +sort of doesn't hurt if +sometimes you leave out + +parentheses if people +understand + +that that's a group. + +And in general, it doesn't +hurt if you put in extra + +parentheses, because that +maybe makes the + +grouping more distinct. + +Lisp is not like that. + +In Lisp, you cannot leave out +parentheses, and you cannot + +put in extra parentheses, +because putting in parentheses + +always means, exactly and +precisely, this is a + +combination which has +meaning, applying + +operators to operands. + +And if I left this out, if I +left those parentheses out, it + +would mean something else. + +In fact, the way to think about +this, is really what I'm + +doing when I write something +like this is writing a tree. + +So this combination is a tree +that has a plus and then a + +thee and then a something else +and an eight and a two. + +And then this something else +here is itself a little + +subtree that has a star +and a five and a six. + +And the way to think of that +is, really, what's going on + +are we're writing these trees, +and parentheses are just a way + +to write this two-dimensional +structure as a linear + +character string. + +Because at least when Lisp first +started and people had + +teletypes or punch cards or +whatever, this was more + +convenient. + +Maybe if Lisp started today, +the syntax of Lisp + +would look like that. + +Well, let's look at +what that actually + +looks like on the computer. + +Here I have a Lisp interaction +set up. + +There's a editor. + +And on the top, I'm going to +type some values and ask Lisp + +what they are. + +So for instance, I can say +to Lisp, what's the + +value of that symbol? + +That's three. + +And I ask Lisp to evaluate it. + +And there you see Lisp has +returned on the bottom, and + +said, oh yeah, that's three. + +Or I can say, what's the sum of +three and four and eight? + +What's that combination? + +And ask Lisp to evaluate it. + +That's 15. + +Or I can type in something +more complicated. + +I can say, what's the sum of the +product of three and the + +sum of seven and 19.5? + +And you'll notice here that Lisp +has something built in + +that helps me keep track of +all these parentheses. + +Watch as I type the next closed +parentheses, which is + +going to close the combination +starting with the star. + +The opening one will flash. + +Here, I'll rub those out +and do it again. + +Type close, and you see +that closes the plus. + +Close again, that +closes the star. + +Now I'm back to the sum, and +maybe I'm going to add that + +all to four. + +That closes the plus. + +Now I have a complete +combination, and I can ask + +Lisp for the value of that. + +That kind of paren balancing is +something that's built into + +a lot of Lisp systems to help +you keep track, because it is + +kind of hard just by hand doing +all these parentheses. + +There's another kind of +convention for keeping track + +of parentheses. + +Let me write another complicated +combination. + +Let's take the sum of the +product of three and five and + +add that to something. + +And now what I'm going to do is +I'm going to indent so that + +the operands are written +vertically. + +Which the sum of that and +the product of 47 and-- + +let's say the product +of 47 with a + +difference of 20 and 6.8. + +That means subtract +6.8 from 20. + +And then you see the +parentheses close. + +Close the minus. + +Close the star. + +And now let's get another +operator. + +You see the Lisp editor here +is indenting to the right + +position automatically to +help me keep track. + +I'll do that again. + +I'll close that last +parentheses again. + +You see it balances the plus. + +Now I can say, what's +the value of that? + +So those two things, indenting +to the right level, which is + +called pretty printing, and +flashing parentheses, are two + +things that a lot of Lisp +systems have built in to help + +you keep track. + +And you should learn +how to use them. + +Well, those are the +primitives. + +There's a means of +combination. + +Now let's go up to the +means of abstraction. + +I'd like to be able to take +the idea that I do some + +combination like this, and +abstract it and give it a + +simple name, so I can use +that as an element. + +And I do that in Lisp with +"define." So I can say, for + +example, define A to be the +product of five and five. + +And now I could say, for +example, to Lisp, what is the + +product of A and A? + +And this should be 25, and +this should be 625. + +And then, crucial thing, +I can now use A-- + +here I've used it in +a combination-- + +but I could use that in other +more complicated things that I + +name in turn. + +So I could say, define B to be +the sum of, we'll say, A and + +the product of five and A. +And then close the plus. + +Let's take a look at that +on the computer and + +see how that looks. + +So I'll just type what +I wrote on the board. + +I could say, define A to be the +product of five and five. + +And I'll tell that to Lisp. + +And notice what Lisp responded +there with + +was an A in the bottom. + +In general, when you type in +a definition in Lisp, it + +responds with the symbol +being defined. + +Now I could say to Lisp, what +is the product of A and A? + +And it says that's 625. + +I can define B to be the sum of +A and the product of five + +and A. Close a paren +closes the star. + +Close the plus. + +Close the "define." Lisp says, +OK, B, there on the bottom. + +And now I can say to Lisp, +what's the value of B? + +And I can say something more +complicated, like what's the + +sum of A and the quotient +of B and five? + +That slash is divide, another +primitive operator. + +I've divided B by five, +added it to A. Lisp + +says, OK, that's 55. + +So there's what it looks like. + +There's the basic means +of defining something. + +It's the simplest kind of +naming, but it's not really + +very powerful. + +See, what I'd really +like to name-- + +remember, we're talking about +general methods-- + +I'd like to name, oh, the +general idea that, for + +example, I could multiply five +by five, or six by six, or + +1,001 by 1,001, 1,001.7 +by 1,001.7. + +I'd like to be able to name +the general idea of + +multiplying something +by itself. + +Well, you know what that is. + +That's called squaring. + +And the way I can do that in +Lisp is I can say, define to + +square something x, multiply +x by itself. + +And then having done that, +I could say to Lisp, for + +example, what's the +square of 10? + +And Lisp will say 100. + +So now let's actually look at +that a little more closely. + +Right, there's the definition +of square. + +To square something, multiply +it by itself. + +You see this x here. + +That x is kind of a pronoun, +which is the something that + +I'm going to square. + +And what I do with it +is I multiply x, I + +multiply it by itself. + +OK. + +So there's the notation for +defining a procedure. + +Actually, this is a little bit +confusing, because this is + +sort of how I might +use square. + +And I say square root of x or +square root of 10, but it's + +not making it very clear that +I'm actually naming something. + +So let me write this definition +in another way that + +makes it a little +bit more clear + +that I'm naming something. + +I'll say, "define" square to +be lambda of x times xx. + +Here, I'm naming something +square, just like over here, + +I'm naming something A. The +thing that I'm naming square-- + +here, the thing I named A was +the value of this combination. + +Here, the thing that I'm naming +square is this thing + +that begins with lambda, and +lambda is Lisp's way of saying + +make a procedure. + +Let's look at that more +closely on the slide. + +The way I read that definition +is to say, I define square to + +be make a procedure-- + +that's what the lambda is-- + +make a procedure with +an argument named x. + +And what it does is return +the results of + +multiplying x by itself. + +Now, in general, we're going to +be using this top form of + +defining, just because it's a +little bit more convenient. + +But don't lose sight of the fact +that it's really this. + +In fact, as far as the Lisp +interpreter's concerned, + +there's no difference between +typing this to it and typing + +this to it. + +And there's a word for that, +sort of syntactic sugar. + +What syntactic sugar means, +it's having somewhat more + +convenient surface forms +for typing something. + +So this is just really syntactic +sugar for this + +underlying Greek thing +with the lambda. + +And the reason you should +remember that is don't forget + +that, when I write something +like this, I'm + +really naming something. + +I'm naming something square, +and the something that I'm + +naming square is a procedure +that's getting constructed. + +Well, let's look at that +on the computer, too. + +So I'll come and I'll say, +define square of + +x to be times xx. + +Now I'll tell Lisp that. + +It says "square." See, I've +named something "square." Now, + +having done that, I can +ask Lisp for, what's + +the square of 1,001? + +Or in general, I could say, +what's the square of the sum + +of five and seven? + +The square of 12's 144. + +Or I can use square itself +as an element in some + +combination. + +I can say, what's the sum of +the square of three and the + +square of four? + +nine and 16 is 25. + +Or I can use square as an +element in some much more + +complicated thing. + +I can say, what's the square +of, the sqare of, + +the square of 1,001? + +And there's the square of the +square of the square of 1,001. + +Or I can say to Lisp, what +is square itself? + +What's the value of that? + +And Lisp returns some +conventional way of telling me + +that that's a procedure. + +It says, "compound procedure +square." Remember, the value + +of square is this procedure, and +the thing with the stars + +and the brackets are just Lisp's +conventional way of + +describing that. + +Let's look at two more +examples of defining. + +Here are two more procedures. + +I can define the average of x +and y to be the sum of x and y + +divided by two. + +Or having had average and mean +square, having had average and + +square, I can use that to talk +about the mean square of + +something, which is the average +of the square of x and + +the square of y. + +So for example, having done +that, I could say, what's the + +mean square of two and three? + +And I should get the +average of four and + +nine, which is 6.5. + +The key thing here is that, +having defined square, I can + +use it as if it were +primitive. + +So if we look here on the +slide, if I look at mean + +square, the person defining mean +square doesn't have to + +know, at this point, whether +square was something built + +into the language or +whether it was a + +procedure that was defined. + +And that's a key thing in Lisp, +that you do not make + +arbitrary distinctions between +things that happen to be + +primitive in the language +and things that + +happen to be built in. + +A person using that shouldn't +even have to know. + +So the things you construct get +used with all the power + +and flexibility as if they +were primitives. + +In fact, you can drive that +home by looking on the + +computer one more time. + +We talked about plus. + +And in fact, if I come here on +the computer screen and say, + +what is the value of plus? + +Notice what Lisp types out. + +On the bottom there, it typed +out, "compound procedure + +plus." Because, in this system, +it turns out that the + +addition operator is itself +a compound procedure. + +And if I didn't just type that +in, you'd never know that, and + +it wouldn't make any +difference anyway. + +We don't care. + +It's below the level of +the abstraction that + +we're dealing with. + +So the key thing is you cannot +tell, should not be able to + +tell, in general, the difference +between things that + +are built in and things +that are compound. + +Why is that? + +Because the things that are +compound have an abstraction + +wrapper wrapped around them. + +We've seen almost all the +elements of Lisp now. + +There's only one more we have to +look at, and that is how to + +make a case analysis. + +Let me show you what I mean. + +We might want to think about the +mathematical definition of + +the absolute value functions. + +I might say the absolute value +of x is the function which has + +the property that it's +negative of x. + +For x less than zero, it's +zero for x equal to zero. + +And it's x for x greater +than zero. + +And Lisp has a way of making +case analyses. + +Let me define for you +absolute value. + +Say define the absolute value +of x is conditional. + +This means case analysis, +COND. + +If x is less than zero, the +answer is negate x. + +What I've written here +is a clause. + +This whole thing is a +conditional clause, + +and it has two parts. + +This part here is a predicate +or a condition. + +That's a condition. + +And the condition is expressed +by something called a + +predicate, and a predicate in +Lisp is some sort of thing + +that returns either +true or false. + +And you see Lisp has a +primitive procedure, + +less-than, that tests whether +something is true or false. + +And the other part of a clause +is an action or a thing to do, + +in the case where that's true. + +And here, what I'm doing +is negating x. + +The negation operator, the +minus sign in Lisp is + +a little bit funny. + +If there's two or more +arguments, if there's two + +arguments it subtracts the +second one from the first, and + +we saw that. + +And if there's one argument, +it negates it. + +So this corresponds to that. + +And then there's another +COND clause. + +It says, in the case where +x is equal to zero, + +the answer is zero. + +And in the case where x +is greater than zero, + +the answer is x. + +Close that clause. + +Close the COND. + +Close the definition. + +And there's the definition +of absolute value. + +And you see it's the case +analysis that looks very much + +like the case analysis you +use in mathematics. + +There's a somewhat different +way of writing a restricted + +case analysis. + +Often, you have a case analysis +where you only have + +one case, where you test +something, and then depending + +on whether it's true or false, +you do something. + +And here's another definition of +absolute value which looks + +almost the same, which says, +if x is less than zero, the + +result is negate x. + +Otherwise, the answer is x. + +And we'll be using "if" a lot. + +But again, the thing to remember +is that this form of + +absolute value that you're +looking at here, and then this + +one over here that I wrote +on the board, are + +essentially the same. + +And "if" and COND are-- + +well, whichever way +you like it. + +You can think of COND as +syntactic sugar for "if," or + +you can think of "if" as +syntactic sugar for COND, and + +it doesn't make any +difference. + +The person implementing a Lisp +system will pick one and + +implement the other +in terms of that. + +And it doesn't matter +which one you pick. + +Why don't we break now, and +then take some questions. + +How come sometimes when I write +define, I put an open + +paren here and say, define open +paren something or other, + +and sometimes when +I write this, I + +don't put an open paren? + +The answer is, this particular +form of "define," where you + +say define some expression, is +this very special thing for + +defining procedures. + +But again, what it really means +is I'm defining this + +symbol, square, to be that. + +So the way you should think +about it is what "define" does + +is you write "define," and the +second thing you write is the + +symbol here-- no open paren-- + +the symbol you're defining and +what you're defining it to be. + +That's like here +and like here. + +That's sort of the basic way +you use "define." And then, + +there's this special syntactic +trick which allows you to + +define procedures that +look like this. + +So the difference is, it's +whether or not you're defining + +a procedure. + +[MUSIC PLAYING] + +Well, believe it or not, you +actually now know enough Lisp + +to write essentially any +numerical procedure that you'd + +write in a language like FORTRAN +or Basic or whatever, + +or, essentially, any +other language. + +And you're probably saying, +that's not believable, because + +you know that these languages +have things like "for + +statements," and "do until +while" or something. + +But we don't really +need any of that. + +In fact, we're not going +to use any of + +that in this course. + +Let me show you. + +Again, looking back at square +root, let's go back to this + +square root algorithm of +Heron of Alexandria. + +Remember what that said. + +It said, to find an +approximation to the square + +root of X, you make a guess, +you improve that guess by + +averaging the guess and +X over the guess. + +You keep improving that until +the guess is good enough. + +I already alluded to the idea. + +The idea is that, if the initial +guess that you took + +was actually equal to the square +root of X, then G here + +would be equal to X/G. + +So if you hit the square +root, averaging them + +wouldn't change it. + +If the G that you picked was +larger than the square root of + +X, then X/G will be smaller than +the square root of X, so + +that when you average +G and X/G, you get + +something in between. + +So if you pick a G that's +too small, your + +answer will be too large. + +If you pick a G that's too +large, if your G is larger + +than the square root of X and +X/G will be smaller than the + +square root of X. + +So averaging always gives you +something in between. + +And then, it's not quite +trivial, but it's possible to + +show that, in fact, if G misses +the square root of X by + +a little bit, the average of G +and X/G will actually keep + +getting closer to the square +root of X. So if you keep + +doing this enough, you'll +eventually get as + +close as you want. + +And then there's another fact, +that you can always start out + +this process by using 1 +as an initial guess. + +And it'll always converge to +the square root of X. So + +that's this method of successive +averaging due to + +Heron of Alexandria. + +Let's write it in Lisp. + +Well, the central idea is, what +does it mean to try a + +guess for the square +root of X? + +Let's write that. + +So we'll say, define to try a +guess for the square root of + +X, what do we do? + +We'll say, if the guess is good +enough to be a guess for + +the square root of X, +then, as an answer, + +we'll take the guess. + +Otherwise, we will try +the improved guess. + +We'll improve that guess for +the square root of X, and + +we'll try that as a guess for +the square root of X. Close + +the "try." Close the "if." Close +the "define." So that's + +how we try a guess. + +And then, the next part of the +process said, in order to + +compute square roots, we'll +say, define to compute the + +square root of X, we will try +one as a guess for the square + +root of X. Well, we have to +define a couple more things. + +We have to say, how is +a guess good enough? + +And how do we improve a guess? + +So let's look at that. + +The algorithm to improve a guess +for the square root of + +X, we average-- + +that was the algorithm-- + +we average the guess with +the quotient of + +dividing X by the guess. + +That's how we improve a guess. + +And to tell whether a guess is +good enough, well, we have to + +decide something. + +This is supposed to be a guess +for the square root of X, so + +one possible thing you can do +is say, when you take that + +guess and square it, do you get +something very close to X? + +So one way to say that is to +say, I square the guess, + +subtract X from that, and see if +the absolute value of that + +whole thing is less than some +small number, which depends on + +my purposes. + +So there's a complete procedure +for how to compute + +the square root of X. Let's look +at the structure of that + +a little bit. + +I have the whole thing. + +I have the notion of how to +compute a square root. + +That's some kind of module. + +That's some kind of black box. + +It's defined in terms of how to +try a guess for the square + +root of X. + +"Try" is defined in terms of, +well, telling whether + +something is good enough +and telling + +how to improve something. + +So good enough. + +"Try" is defined in terms of +"good enough" and "improve." + +And let's see what +else I fill in. + +Well, I'll go down this tree. + +"Good enough" was defined +in terms of + +absolute value, and square. + +And improve was defined in +terms of something called + +averaging and then some other +primitive operator. + +Square root's defined in terms +of "try." "Try" is defined in + +terms of "good enough" +and "improve," + +but also "try" itself. + +So "try" is also defined in +terms of how to try itself. + +Well, that may give you some +problems. Your high school + +geometry teacher probably told +you that it's naughty to try + +and define things in terms of +themselves, because it doesn't + +make sense. + +But that's false. + +Sometimes it makes perfect +sense to define things in + +terms of themselves. + +And this is the case. + +And we can look at that. + +We could write down what this +means, and say, suppose I + +asked Lisp what the square +root of two is. + +What's the square root +of two mean? + +Well, that means I try one +as a guess for the + +square root of two. + +Now I look. + +I say, gee, is one a good enough +guess for the square + +root of two? + +And that depends on the test +that "good enough" does. + +And in this case, "good enough" +will say, no, one is + +not a good enough guess for +the square root of two. + +So that will reduce to saying, +I have to try an improved-- + +improve one as a guess for the +square root of two, and try + +that as a guess for the +square root of two. + +Improving one as a guess for the +square root of two means I + +average one and two +divided by one. + +So this is going +to be average. + +This piece here will be the +average of one and the + +quotient of two by one. + +That's this piece here. + +And this is 1.5. + +So this square root of two +reduces to trying one for the + +square root of two, which +reduces to trying 1.5 as a + +guess for the square +root of two. + +So that makes sense. + +Let's look at the rest +of the process. + +If I try 1.5, that reduces. + +1.5 turns out to be not good +enough as a guess for the + +square root of two. + +So that reduces to trying the +average of 1.5 and two divided + +by 1.5 as a guess for the +square root of two. + +That average turns +out to be 1.333. + +So this whole thing reduces to +trying 1.333 as a guess for + +the square root of two. + +And then so on. + +That reduces to another called +a "good enough," 1.4 + +something or other. + +And then it keeps going until +the process finally stops with + +something that "good enough" +thinks is good enough, which, + +in this case, is 1.4142 +something or other. + +So the process makes +perfect sense. + +This, by the way, is called +a recursive definition. + +And the ability to make +recursive definitions is a + +source of incredible power. + +And as you can already see I've +hinted at, it's the thing + +that effectively allows you to +do these infinite computations + +that go on until something is +true, without having any other + +constricts other than the +ability to call a procedure. + +Well, let's see, there's +one more thing. + +Let me show you a variant of +this definition of square root + +here on the slide. + +Here's sort of the same thing. + +What I've done here is packaged +the definitions of + +"improve" and "good enough" +and "try" inside "square + +root." So, in effect, what +I've done is I've built a + +square root box. + +So I've built a box that's the +square root procedure that + +someone can use. + +They might put in 36 +and get out six. + +And then, packaged inside this +box are the definitions of + +"try" and "good enough" +and "improve." + +So they're hidden +inside this box. + +And the reason for doing that +is that, if someone's using + +this square root, if George is +using this square root, George + +probably doesn't care very much +that, when I implemented + +square root, I had things inside +there called "try" and + +"good enough" and "improve." And +in fact, Harry might have + +a cube root procedure that has +"try" and "good enough" and + +"improve." And in order to not +get the whole system confused, + +it'd be good for Harry to +package his internal + +procedures inside his +cube root procedure. + +Well, this is called block +structure, this particular way + +of packaging internals inside +of a definition. + +And let's go back and look +at the slide again. + +The way to read this kind of +procedure is to say, to define + +"square root," well, inside that +definition, I'll have the + +definition of an "improve" and +the definition of "good + +enough" and the definition of +"try." And then, subject to + +those definitions, the way I do +square root is to try one. + +And notice here, I don't have to +say one as a guess for the + +square root of X, because since +it's all inside the + +square root, it sort of +has this X known. + +Let me summarize. + +We started out with the idea +that what we're going to be + +doing is expressing imperative +knowledge. + +And in fact, here's a slide +that summarizes the way we + +looked at Lisp. + +We started out by looking at +some primitive elements in + +addition and multiplication, +some predicates for testing + +whether something is less-than +or something's equal. + +And in fact, we saw really +sneakily in the system we're + +actually using, these aren't +actually primitives, but it + +doesn't matter. + +What matters is we're going +to use them as if they're + +primitives. + +We're not going to +look inside. + +We also have some primitive +data and some numbers. + +We saw some means of +composition, means of + +combination, the basic one being +composing functions and + +building combinations with +operators and operands. + +And there were some other +things, like COND and "if" and + +"define." But the main thing +about "define," in particular, + +was that it was the means +of abstraction. + +It was the way that +we name things. + +You can also see from this slide +not only where we've + +been, but holes we +have to fill in. + +At some point, we'll have to +talk about how you combine + +primitive data to get compound +data, and how you abstract + +data so you can use large +globs of data as + +if they were primitive. + +So that's where we're going. + +But before we do that, for the +next couple of lectures we're + +going to be talking about, first +of all, how it is that + +you make a link between these +procedures we write and the + +processes that happen +in the machine. + +And then, how it is that you +start using the power of Lisp + +to talk not only about these +individual little + +computations, but about general +conventional methods + +of doing things. + +OK, are there any questions? + +AUDIENCE: Yes. + +If we defined A using +parentheses instead of as we + +did, what would be +the difference? + +PROFESSOR: If I wrote this, if +I wrote that, what I would be + +doing is defining a procedure +named A. In this case, a + +procedure of no arguments, +which, when I ran it, would + +give me back five times five. + +AUDIENCE: Right. + +I mean, you come up with the +same thing, except for you + +really got a different-- + +PROFESSOR: Right. + +And the difference would +be, in the old one-- + +Let me be a little +bit clearer here. + +Let's call this A, like here. + +And pretend here, just for +contrast, I wrote, define D to + +be the product of +five and five. + +And the difference between +those, let's think about + +interactions with the +Lisp interpreter. + +I could type in A and Lisp +would return 25. + +I could type in D, if I just +typed in D, Lisp would return + +compound procedure D, because +that's what it is. + +It's a procedure. + +I could run D. I could say, +what's the value of running D? + +Here is a combination +with no operands. + +I see there are no operands. + +I didn't put any after D. And +it would say, oh, that's 25. + +Or I could say, just for +completeness, if I typed in, + +what's the value of running A? + +I get an error. + +The error would be the same +one as over there. + +It'd be the error would say, +sorry, 25, which is the value + +of A, is not an operator that +I can apply to something. \ No newline at end of file diff --git a/2fjZhoifOiM.txt b/2fjZhoifOiM.txt new file mode 100644 index 0000000000000000000000000000000000000000..8c3e8da2cabd77ceb41eeb6b285829e9e3d6eeff --- /dev/null +++ b/2fjZhoifOiM.txt @@ -0,0 +1,4202 @@ +The following content is +provided under a Creative + +Commons license. + +Your support will help MIT +OpenCourseWare continue to + +offer high quality educational +resources for free. + +To make a donation or view +additional materials from + +hundreds of MIT courses, visit +MIT OpenCourseWare@mit.edu. + +PROFESSOR: Any issues with +the project so far? + +Have you gotten your +repositories set up and the + +compiler works and all this? + +So I'm glad to see a +lot of people are + +getting a early start. + +In fact, if you haven't, a lot +of other people in the class + +are getting an early start +so you're behind already. + +So go there, get the project +started, because these + +performance projects can +run for long time. + +And in fact, last year a lot of +people asking, when is my + +project done? + +Because a lot of times when you +have a project there's a + +certain set of-- + +we ask you to implement. + +Once that's implemented, +the project is over. + +But when is a performance +project done? + +And the only answer I L when the +deadline comes because you + +can always shave 10% here, +you can get a better data + +structure, you can +keep like kind of + +tweaking for a long time. + +And a lot of you will do. + +In fact, to give you a warning, +last year, the + +performance difference between +the best project won, versus + +the worst one, even the worst +one got about 50% better than + +the code we gave. + +But the best one got 1,000x +better than the worst one + +because they figured out right +data structures, they changed + +algorithms, they did some +precomputation, they did a lot + +of cool stuff, and so there's +a lot to get if you do this + +project right. + +So just don't be happy if you +just got 10%, 50%, and say, + +yeah, I got some performance. + +Think carefully. + +There's a lot of room in +this project for you to + +gain, so work hard. + +I'm not saying this +yields 1,000x. + +I don't know. + +I haven't exactly seen all the +things you can do, but there + +could be a huge thing +you can win. + +So think through not just small, +low hanging fruit, but + +there could be interesting +things you can do that can + +have impact. + +So today what I am going to do +is talk a little bit about + +basics of performance +engineering. + +Kind of things you guys +would probably + +know, rules to follow. + +So to start that if you look at +performance engineering, it + +can fit into a couple +of classes. + +One is you want to get a maximum +out of the compiler + +you have, the processor you +have, the system you have, you + +want them running efficiently. + +So if you look at the matrix +multiple examples we did this + +in the first class it's saying, +OK, we have a system, + +we have this very well known +algorithm, very long piece of + +code, and we want to get the +best out of that thing, how do + +you go about doing that? + +That's mainly the focus there. + +Then when you we looked at +the bithacking stuff that + +Professor Leiserson did last +time, it's mainly about really + +changing the algorithms. + +We basically said, OK, look, if +we're thinking about this + +as bits there might be +fundamental different ways to + +approach this problem. + +By doing that we can actually +get really good performance. + +OK, we'll be doing +more of that. + +Today we are going to focus on +this two middle criteria. + +What we are going to do is we +are going to stay within the + +spirit of the program +that was given. + +Even though we are going to +change the program a little + +bit, we are not going to +fundamentally change what the + +program does. + +So the same computations would +be done basically on the same + +day but what we will do is we +will change certain aspects + +how it's being done to gain some +performance advantages. + +So the nice thing about this +one is you don't have to + +really understand the algorithm, +you don't have to + +understand lot of what's going +on in, what's implementation. + +This is more-- + +you can do this as a +mechanism sub out. + +The unfortunate thing is there's +not theory in these + +type of engineering. + +There's not something we +can prove, here's the + +optimal you can do. + +[UNINTELLIGIBLE] nice there. + +So normally performance +programming basically knows + +that you need to understand +everything that's in modern + +performance. + +That means all the way from high +level algorithms, every + +layer in the systems, the +compiler, the hardware, the + +disks, all those things can +impact performance. + +So it's normally when in +performance to understand + +everything that +[UNINTELLIGIBLE]. + +This is very different from +a lot of what you + +guys are used to. + +It is staying within +one layer. + +You say, OK, this is my +layer, I don't care + +what's on any of it. + +I don't know care much about-- + +I'm going to work on that. + +And the thing that normally +comes and bite you is the + +other layers that you just +take for granted. + +In performance it's basically +going through end to end. + +That's the normal thing. + +And normally, if you are an +experienced performance + +engineer, you know when +the problems show up. + +And you can kind of have a basic +understanding, here are + +the kind of places where they +have performance problems. + +And so a good performance this +is where experience comes in. + +So instead of saying looking at +the code and say I have no + +idea what's going on, you can +say, let me think about this, + +this is where normally +something goes wrong. + +And then you have to have the +skill to zoom in and identify + +the problem fast. + +And most of performance +engineering is basically a + +good dose of common sense. + +So have kind of a good +person who can + +do really good debugging. + +Is you have kind of a built in +algorithm how do you go about + +doing something. + +And a lot of times you know +your strengths, kind of + +mistakes you make, you look at +those things first, and the + +same way performance engineering +there has to be + +kind of a back of your +head algorithm. + +And hopefully at the end of +this class you're going to + +develop that. + +And in this lecture what I'm +trying to do is come up with a + +set of rules, that kind of +patterns that occur regularly, + +mistakes lot of people make, +and that can have a + +substantial performance impact, +or performance gain if + +you do that. + +If you have done the design +patterns lectures in 005, yes, + +you do, you will see +some similar ideas. + +What you're doing is kind of +say, OK, here's a bunch of + +patterns in there, +what we can do. + +So what I'm doing is I am +following some very + +interesting set of rules that +was developed by this guy + +named John Bentley. + +He wrote a book called +Programming Pearls, I guess. + +It's a very old book, last +published in 1990. + +It talks about a lot of the +small, interesting things you + +can do to get really +good performance. + +It's out of print. + +This is probably one +reason to probably + +go to library probably. + +Libraries have this copy but you +can't get it on Amazon or + +online so that's unfortunate. + +But what I'm going to do is +I'm going to kind of read + +through it and some of these +rules, modified to suit the + +current program and practices. + +So he looked at it and said +there are basically two kinds + +of things you can do, +we can modify data, + +you can modify code. + +And then went down more into +details, if you modify data + +you can do three things. + +You can pay one against other, +you can pay by space and gain + +time, you can pay from time and +gain space, and there's + +sometimes, if you're lucky, you +have a win-win situation + +when you can get both space +and time advantage. + +So let's go through a couple +of those things. + +So if you [UNINTELLIGIBLE] + +by space for time, there +are four things. + +I'm going to go through all +this four data structure + +augmentation, storing +precomputed results, caching, + +and lazy evaluation. + +So what's data structure +augmentation? + +So here what you want to do is +you have a data structure that + +you keep the data. + +You add some extra information +to your data structures. + +That can mean the common +operations run much quicker. + +OK? + +And when this is good, because +what do you want to do is this + +adding this information +has a clear benefit. + +Calculating additional +information has to + +be cheap and easy. + +So you don't want a situation +where we have this + +information, you've spent all +this time calculating this + +additional information and +you're not using it that much, + +or the use doesn't give you +that much advantage. + +So you have amortize +the cost in here. + +And then also keeping that +information current can't be + +too difficult, because +sometimes you can add + +information into a data +structure that makes it very + +hard to make sure that that +information is kept up to + +date, and then you're spending +more time and you're + +[UNINTELLIGIBLE] + +that. + +So a couple of quick +examples in here. + +Something like if you have a +single link list, if you are + +doing a lot of deletion it's a +very expensive proposition + +because you might had to walk +through the entire list to + +delete an element. + +But if you are in a doubly +linked list, a division + +operation is basically +order one instead of + +[UNINTELLIGIBLE]. + +So suddenly you realize, I'm +doing a lot of deletions, + +suddenly I can say I'm adding +this additional information to + +my link list, I'm maintaining +point as to both directions, + +make this one operation +run much faster. + +This is a very classic example +of adding additional + +information. + +Another one is what we call +reference counting. + +So assume I have objects +somewhere and I want to figure + +out who points to me. + +In terms of garbage collection +you want to see if anybody + +points to me. + +The normal way to do that is +look for every other thing + +saying is anybody pointing to +that person, had to walk + +through every possible object +out there to find if anybody's + +pointing to this object. + +That's what normal garbage +garbage collectors do. + +But there's something +easier, what you + +call reference counting. + +That means if each object keep +a count on the amount of + +pointing coming to itself then +to ask that question, is this + +really true? + +And you look and say, +OK, what's my count? + +If there's count to zero +nobody's pointing to me. + +But of course every time you +point to that object to update + +the counter, every time you +point away or take away an + +object that points you have to +subtract the counters, you had + +to keep that information +additional. + +But by doing that discussion +about asking whether anybody + +points to you becomes a +very trivial question. + +So here's a case you add a +little bit more information + +and that makes some questions, +some things you want to know + +trivial and very easy to do, +and you have to figure out + +where the [UNINTELLIGIBLE] + +is. + +So here's one interesting +thing. + +Go a little bit further, +one thing you can do is + +precompute, result +and storage. + +What you are doing is you want +some calc computation and + +instead of every time you want +that in recalculating it, say, + +OK, I'm going to compute them +early and I'm going to store + +it somewhere, and then every +time I want then I + +just do a look up. + +So when is this going +to be useful? + +So this is-- + +the rest of my slides are going +to have this kind of + +form, I'm going to give you a +problem, tell you when it's + +going to be useful, and +use some examples. + +First of all, the function you +are calculating has to be + +somewhat expensive, otherwise if +it is just a simple single + +operation look up is probably +too slow to compile. + +And the function has to be very +heavily used, because if + +you are calling it many, many +times it's worth storing it. + +Another very important +thing is the argument + +space has to be small. + +You might be asking for calling +the function millions + +and millions of time, but every +time you call you give a + +different set of arguments. + +If the arguments are very large +it can be many, many + +things here, and then it's not +easy to store everything. + +And it might take more time to +find all the solutions for all + +the arguments. + +So if the arguments +have to be small. + +And of, course, a couple +additional things, results + +only depends on the arguments. + +So assume the function results +actually look time of day to + +the computation. + +OK, that doesn't work, because +then every time you call the + +function, you get different +result. + +That doesn't work that much. + +And functions shouldn't +have side effects. + +What that means is if you call +the function, if it is + +modifying some global variable, +global state. + +OK. + +Then if you keep the call, if +you don't call the function + +that might not happen, so you +want to make sure that this + +function is something can not +call and give the results and + +the state of the system +won't change. + +And another interesting, nice +thing to have is function + +determinants, that means every +time you call the function you + +get the same four arguments, +you get the same results. + +So this is a long list. + +Some of the things I will go, +so for an example, OK, so + +instead of me getting there +getting all the things I want, + +you [INAUDIBLE] + +when I give a prescription like +the thing, what kind of + +things can I do in this way +that might be helpful? + +Can anybody come up with +an interesting example? + +[UNINTELLIGIBLE] + +would precompute and save. + +AUDIENCE: Anytime you do +dynamic programming. + +PROFESSOR: Anytime you +dynamic program. + +This is dynamic programming, +it's a very good way, later we + +probably go get a little +bit into that. + +Where you precompute +and save results. + +OK, that's very sophisticated +answer. + +Good. + +Any other things you +can think of? + +That's almost a meta answer +that's in that class of things + +you can do. + +Any problem there that you have +encountered that you'd + +rather precompute and save that +would be a big, big win. + +AUDIENCE: Operations with large +primes that [INAUDIBLE]. + +PROFESSOR: Operations with? + +AUDIENCE: Large primes. + +PROFESSOR: Large primes, +operations in + +large primes, yes. + +If you are doing that, +especially if this fits into + +this argument space +small apart. + +If the large primes are, any +large primes then you might + +not call it multiple times. + +So here I want to give you kind +of a template that what + +happens here. + +So what you want to do is at +initialization time I get this + +function initialized, what I +do is I precompute for all + +arguments what the results are +stored at, and then every time + +you go apply the function I +just basically, instead of + +calling the function, I just +look at this table. + +OK. + +So then would this +be a bad idea? + +AUDIENCE: Because you know this +early ahead of time you + +know that you're going to be +calling the function for all + +of your arguments. + +PROFESSOR: So if the argument +space is very large or if you + +don't call the function that +many times, or as I said, it + +might only call for very small +number of arguments, + +[UNINTELLIGIBLE] + +this might not be a good idea. + +OK? + +So we will go. + +As we improve, you'll see some +other things that actually + +address that. + +So here's an interesting way of +doing a use case in here. + +So what I have here is +Pascal's Triangle. + +How many people know +Pascal's Triangle? + +OK, good, so I don't have +to explain that. + +So here is a simple computation + +for Pascal's Triangle. + +So what I'm doing is in order +to calculate this value I am + +calling these two values +and adding that. + +OK? + +But the problem is that this +will call- so it kind of call + +exponentially more and +more doing that. + +So you'd say exponential +rhythm. + +However, what I can do in +Pascal's Triangle is I can + +basically compute it at the +beginning by storing the + +previous role, or previous set +of values in and then previous + +role, and every time I'm calling +I just basically have + +to look up the two elements +in the previous role. + +Trying to get my mouse, OK. + +Only have to look at the two +elements on the previous role. + +I added up, I will never have +to compute beyond that. + +So, in fact, by just doing +this one I have taken + +exponential algorithm to +basically lead a path through + +the data, basically. + +This actually become a square, +because if you have some + +depth, I had to do i squared-- + +become a square, pass +through the data. + +If I'm looking for n, I +don't know how to do + +exponential look up. + +Everybody saw this? + +So this is a nice way, simple +way I'm just doing a simple + +storing this data, however in +here I had to calculate, I + +need to know how much maximum +of that, and calculate and I + +just look up. + +And here the [UNINTELLIGIBLE] + +if you calculate a little bit +extra, who cares, I'm OK. + +And another interesting +thing is Fibonnaci. + +And again, here, if you do +keeping the previous value, in + +here, you're actually changing +from exponential algorithm, to + +in here basically a linear +calculation. + +OK? + +So this is almost an algorithmic +change here. + +I kind of lied when +I said it's just a + +data structure change. + +But just a simple data structure +change made an + +algorithm difference. + +So the other interesting thing +you can do is caching. + +So what that means is if you +have a heavily used function + +you can keep some number of +previous basically results + +from calling that function. + +This has a lot of caveats +so let's go + +through this carefully. + +Again the function has to be +expensive, otherwise it's not + +worth doing all that work. + +Functions have to be heavily +used, otherwise you're + +calculating and if you don't +reuse it it's not worth doing + +all the worth. + +Here the arguments space can be +large, OK, because you are + +not calculating everything, you +can have a large argument + +space, and that's OK. + +And then there's another thing +called temporal locality. + +Anybody knows what temporal +locality means? + +OK what. + +AUDIENCE: The same arguments are +called [UNINTELLIGIBLE]. + +PROFESSOR: Yeah, so a lot of +times we realize that if you + +go into the caching and +stuff like that. + +We really get into that in +hardware when you talk about + +hardware lecture. + +So what happens is yes, we have +observed that if I have a + +set of arguments and if I +calculate most of the times I + +will have the same arguments +very quickly time-wise. + +So if I calculate something, +then for a short time I might + +reuse those arguments again and +again, so that's called + +temporal locality. + +So caching works when there's a +very good temporal locality. + +And then there's two other +things we want to do because + +we won't have hash function that +means because a lot of + +arguments from that we only get +one value to look up where + +I store my cache, have to have +a hash function, but to + +calculate it by argument. + +Sometimes if the arguments are +too complicated you might not + +be able to calculate a good +hash function and the hash + +function has to be good. + +What do you mean by a +good hash function? + +AUDIENCE: [INAUDIBLE]. + +PROFESSOR: Yeah, no +[UNINTELLIGIBLE]. + +That means they tend to be +a good distribution. + +So given most of the arguments +it shouldn't be ending up as + +the same value again, so you +should have good distribution + +when you call with different +arguments. + +And the final results only +depend on the arguments that's + +again otherwise you have a +problem and the function + +[UNINTELLIGIBLE] + +if your [UNINTELLIGIBLE] +this important. + +And there's another thing +called coherence. + +So what that means +is I keep some + +precalculated values in here. + +And sometime this if results +are only dependent on the + +arguments you don't have +that much of an issue. + +But sometimes you might in the +situation that the results are + +dependent on the arguments and +some other things like the + +time of the day or whatever. + +And if you want full coherence, +what you want to + +make sure is-- + +many of you know that the +results might be varied. + +I need to understand +that, I need to + +invalidate all the cache. + +And suddenly the data or the +user changed so that thing I + +memorized only works for User +A, now went to User B, the + +results are wrong and I had to +get rid of all the results. + +Or there are some cases where +you could say, yeah, little + +bit of things I can tolerate, +like for example, a really far + +fetched example is something +like if you're looking at a + +web page on a search. + +OK, you don't have a good +guarantee that all the web + +pages in the world are +in that search. + +If you're a little bit late +getting a new web + +page, then you're OK. + +So you can do tolerate +sometimes, a lot of times, if + +you can tolerate these kind of +things you can have huge + +performance impact. + +You don't have to be exact. + +So some of these projects we +look we look at these kind of + +ideas, of tolerate a little bit +of a slack and getting a + +good performance out of that. + +So here's the kind of code, I +put a lot of code in my slides + +because not I won't explain +everything but since these + +online if you want to figure out +what the right template is + +you can look at it. + +I have no idea why this +is moving on me. + +OK, OK, here we go. + +So what you first have to say +is every time you cache a + +value you have to know, I had +to know old arguments and + +results, I had to store that, +and then I'm keeping this many + +precomputed values in here. + +And so every time I call the +function with arguments first + +I have to see I had to get the +get the has with these + +arguments because that might be +the place, this buffer disk + +just might be the place I have +stored a previously computed + +[UNINTELLIGIBLE]. + +Then you say, OK look, is my +[UNINTELLIGIBLE] stored, has + +the same argument. + +If that means I already have +that precomputed, at that + +point I just return it, I +have no issue in there. + +Otherwise you're to call the +function because I haven't + +stored it, and then I will go +about storing the value + +because I calculated I need a +storage because the next time + +I call these arguments I want +to get the same results, and + +then I return the result. + +OK. + +Is this kind of clear, how +this caching works? + +OK, what's a good place for +caching versus precomputing? + +Any idea what can make a good +scenario where actually + +caching can have a big impact? + +You have heard a lot of things +that have the word cache + +associated with it, and you can +say, OK, what that means. + +AUDIENCE: Web browsing. + +PROFESSOR: Web browsing OK, you +web browse actually that's + +a cache, because there's a good +probability that if you + +look at a page and you might be +refreshing that page or you + +might be looking at that page, +so a lot of times what you do + +is you keep a copy locally, and +the next time you ask for + +that and if you have a local +copy you can give + +that local copy back. + +And then of course there's some +issues about how to make + +the local companies stay, the +coherence issues and stuff + +like that it can get complicated +but that's a + +situation where actually +you can use caching. + +So finally, in this category, +we are going to talk about + +lazy evaluation. + +So lazy evaluation means +basically a lot of times you + +might ask for value but you +might not really need it at + +that point. + +Just keep the computation to the +side without doing it and + +then do the computations only +when you really, really need + +the result. + +So basically this is useful, a +lot of times you might try to + +compute a lot of values but +only a certain of that + +actually is used. + +And at that point you just +basically further that + +calculation and only use it +when it's actually done. + +The nice part is when can be +done in a function call, and + +also results can be calculated +kind of incrementally. + +And also, the arguments or +what's needed to calculate the + +results can be nicely packaged +up so it can be + +recalculated later. + +So here what you do here is in +the precomputing is something + +like precomputing but you don't +precompute early, at the + +beginning nothing +is precomputed. + +When you only ask to apply a +function then if there's no + +precomputed value you'll +recompute, otherwise you just + +return the value. + +So if you compare this one +Pascal's Triangle beforehand I + +just computed, there's a bunch +of values in here and kept it. + +OK assuming OK up to +PDMAX I will have + +the results in there. + +But you might not do that. + +PDMAX might be very large and +you might be looking only for + +small Pascal Triangle. + +So instead of doing that, what +you can do is you can do this + +way, you can keep the array for +results, assume everything + +is normally in [UNINTELLIGIBLE] + +global array. + +and then what happens is you +look at the results if the + +results is greater than zero we +are what you're looking at, + +that means, ah-ha. + +I have calculated it. + +I have a new value, I +just iterated it. + +I'm happy. + +Otherwise I will call Pascal +by recalculating values + +because I don't have the +current results. + +And once I get it +I will store it. + +Once I get the value I will +basically, I will calculate + +the Pascal, I will store it and +I will return the value. + +So what that means is this value +of the Pascal yx will be + +only calculated once fully, and +afterward every other time + +you lose that you actually +use the previous one. + +This works very nice, this works +both very nice about + +precomputation but you don't +pay that extra overhead. + +So you are doing the minimum +amount of computation. + +You can never exceed the +computation of the normal + +computation. + +So if you only ask for Pascal +very small one, that's exactly + +the work we [UNINTELLIGIBLE] +do. + +But it will also really use this +kind of exponential blow + +up that happens in the +normal computation. + +So this is kind of the you can +have the cake and eat it too + +in this work. + +OK good. + +So now let's switch from space +for time, for time for space. + +OK? + +So here, one thing you can do +is if you have a huge amount + +of data what you can do is you +can store the data in some + +kind of reduced form and then +what you can do is then you + +can get a big compression of +data basically and then as you + +need the data you can do some +more computation to get the + +data you want. + +So what you're doing is you are +really reducing the space + +you need but now you are paying +by time to get access + +to that data. + +So this is why [UNINTELLIGIBLE] + +storage is at a premium. + +If you look at systems before +1980s everybody had to do it + +because storage was a premium +and all the memory and disk + +space was so complicated +everything got + +compacted in there. + +Now, most your laptop and +desktops, you don't care, you + +have enough space. + +However, if you got things +like embedded devices and + +things like that, this still +becomes a issue. + +Or if you have a very large data +set it becomes an issue. + +And what you can do is by +compressing, drastically + +reduce the data size. + +And you can do it in different +ways, sometimes you + +can do it in batch. + +That means you keep the data +compressed, expand it all, and + +process, hopefully you +have room for that. + +Or sometimes if you don't have +room you do it by streams, + +that means you're looking at a +small amount of data expanded, + +work at it and then either throw +it or again compress it + +and put it back in. + +And hardest thing is if you +actually do random access. + +That means you'll randomly go +to some data, expand and + +understand that sometimes +there's some complications. + +So there are a bunch of packing +methods and some + +simplest things are use +a small data size. + +So right now you're dealing with +64 bit words, you can say + +wait a minute, why does this +data only need 8 bits? + +Why do you keep storing +everything 64-bit if my data + +maximum can be only 0 to 256. + +I can use 8 bits. + +Or I can look at that and I +can use small data size, + +that's something. + +And a lot of people realize a +lot of data we are storing are + +just zeros. + +There are many different data +structures, you have huge data + +structures and most +of it's zeroes. + +And eliminating zeroes in many +instances can you get a long + +way in many, many, many +data storage. + +And something like LZ77 +eliminates repetition. + +So a lot of times what you +find in there you have + +repetitive patterns you can +eliminate that and then, of + +course, you can go into a +lot more complicated. + +heavy-weight compression. + +So to just give you a feel for +what compression is like I + +found this cute animation so +I will show it to you. + +So here is the input stream, but +it has this corrector LA, + +and then it has some notion +about how much a repetition it + +has, corrector O and 0 3. + +So what happens if it's +just a character? + +It will get taken in, so these +two correctors go. + +Now these two forces from the +point I point in here go to + +inwards, and repeat +it four times. + +What that means is basically in +here it will get repeated + +four times because that 2 4. + +So that means instead of having +these four correctors + +in there, what it had was it had +two things, and then all + +get repeated three times and +then it'd get shifted in here. + +So instead of having ten +correctors before, we had 2, + +3, 4, 5, 6, 7. + +Seven, out of seven correctors +you compress you stored + +information off ten correctors +because of repetition. + +OK, so this is a very simple +scheme that people use to do + +this LZ77 compression. + +More complicated thing you can +do a lot of times is build an + +interpreter. + +What that means is you have some +complex data, instead of + +storing the data you have a +summary of the data stored. + +OK. + +And then what you can do is +you can do this abstract + +representation. + +I mean you were already +tested. + +Like, for example, you +[UNINTELLIGIBLE] + +exactly doing that. + +What you do is you start off +storing all the beats of + +machine instructions. + +You store it in abstraction +called add register names or + +something like in smd. + +What that means is you're +building a very simple + +abstraction which that would be +more complex sometimes to + +store than the actual data. + +So in here, things like if you +look at a java byte cord, + +that's a nice interpreter. + +So instead of storing all this +complex instructions you + +interpret, you stored some +higher level set of + +instructions, that byte code, +that is much more compressed + +and that you run you map it into +the machine instructions. + +There's a lot of advantages +other than just compressing + +storage, it's a nice +abstraction, you can change it + +at the highly level easily. + +OK, so those are something that +you can do, you give up + +one thing for the other. + +And if you're lucky you can have +the cake and eat it too. + +Which is you get both space +and time at the same time. + +So we looked at it in last +lecture sometime. + +This is bithack. + +Bithacks kind of gave you that +because instead of having 64 + +bit word to represent you got +64 of them into one big + +stream, if you're only +representing zeroes and ones. + +And by doing that you get a lot +more compressed storage. + +Also now you can operate that +entire 64 in parallel. + +We can generalize it a little +bit, so instead of just doing + +64 Boolean, sometimes you can +do in a 64 bit word, you can + +store two 32 bit words, +or four 16 bit words, + +so eight 8 bit words. + +OK. + +In [UNINTELLIGIBLE] + +is called a Memex +SSE extensions. + +Normally it's called SIMDs, a +single instruction multiple + +data, because what you do to +that, all the bits, are the + +same thing for everybody. + +So if you're adding you're +doing same add + +for both of the data. + +And because of that you +basically going to get both + +the compression. + +Because now for 64 bit you are +keeping two thing, or four + +things, or eight things. + +Also, now you're operating. + +In a single operation you can +get the same operation + +happening to all the data. + +So you're getting both storage +and fast operations in here. + +Of course if you only look at +one you have to do a little + +bit more work, you take it out +of that data word, so if + +you're just looking at +[UNINTELLIGIBLE] + +thing can be expensive. + +So when is it viable? + +You'll do the same operations +all the data. + +OK, if each day you do something +different it's not + +that great and items can be +stored in contiguous memory, + +so when you load you can say I'm +getting nice in one word, + +if I'm getting two 32 bit, so +four 16 bit, so I can do that. + +And you don't end up picking +each operations and doing + +individual things too much. + +So if you are to pick each +individual elements a lot, + +then you have to actually now +pick apart that word and that + +can be multiple operations +and expensive. + +So here's a simple example. + +This, I think, from after last +bithacks class, this is a + +little bit, you probably know, +can come up with enough + +examples here. + +What I'm doing is I'm doing +a Battleship board game. + +So you represent the board, and +the interesting thing in + +this board is to know whether +that location has something or + +not, it's empty or full, that's +all I need to know. + +And so normally if I do this +board game I can have two + +boards in here. + +But what I'm doing is having +this overlap calculations, + +saying of the two boards, +how many things overlap. + +I can just have each location +represented by integer, but + +then only the representing one +value is not good enough. + +One thing I can do is I can just +put each row into one 64 + +bit word, and then instead of +doing the two loops I can, in + +one loop, I can just do the +ending off each row, and I get + +the result. + +So after the the bithack +lecture, this should be kind + +of trivial. + +OK, everybody get it? + +Anybody have questions so far? + +Are we all on the same page? + +OK, good. + +There's a lot of blank faces so +I want to help, I'll start + +asking more questions +or something. + +OK, so that's modifying data. + +Now we're going to modifying +code, where you will change + +the programs to actually get +performance and that can be + +done in loops, logic rules, +procedures, expression, and + +parallelism rules. + +When we get to parallelism rules +we will actually do a + +lot more on them in future +lectures, but I just want to + +address some basic stuff now. + +Bunch of different loop rules. + +I will go each of them +individually. + +So first of all, why loops? + +Why do you think loops +are so important? + +OK, somebody who hasn't +answered the question. + +Why is loops so important? + +Why are we like really focused +on loops all of the time? + +Anyone want to answer +here, this side? + +OK. + +AUDIENCE: [INAUDIBLE] in terms +of maintainability, + +[INAUDIBLE]? + +PROFESSOR: Yeah, so loops +give you a nice, simple + +abstractions it's easier to +maintain instead of having + +multiple computed times. + +Yes, instead of having same +thing repeated millions of + +times for the same thing, if I +write a loop, it's much more + +concise representation. + +That's why I think we do a lot +of loops, because it makes + +programs easier. + +In fact, assume this word, +loops didn't exist, OK? + +If loops doesn't exist that +means you're going at each + +instruction get executed +only one time. + +If you have a 3 gigahertz +machine that requires even if + +you do one instruction per cycle +in 32 bit instruction + +you need 12 gigabytes of +instruction per second, if you + +only execute one instruction +once. + +That means if you have 100 +gigabyte disk full of a + +program you go through each +instruction the entire 100 + +gigabytes in 8 seconds. + +OK. + +Of course this can never be +done, that means you cannot + +feed 100 gigabytes into the +processor in 8 seconds. + +That won't work because of +the disk access time, + +caches, and all those. + +Even if it is doable, what +that means is the entire + +reason your Pentium is running +at 3 gigahertz and actually + +showing like it's running as 3 +gigahertz is because you are + +using instructions +many, many times. + +You have loops that run +millions of times. + +If you don't have loops you +can use whatever the data + +machine you build in '004 and +that probably as fast you + +could get because of this +instruction thing. + +So loops are critical, and +loops are what makes our + +programs run fast. + +Repeated execution of same +instruction again + +and again and again. + +OK. + +So in the world, in that sense, +if you think about + +this, unless there are some +instruction that's run + +millions of times, you can +never keep this ferocious + +beast's appetite full because +there will always be new + +instructions. + +So because of that looking at +loops, if you want to get good + +performance just looking at the +most important loops, the + +inner loops, and just doing only +that we'll probably get + +you most of way in +many, many cases. + +And basically I could even say +99 of the program execution + +time is in 10% of the code, +even, more than + +that in many cases. + +Because otherwise +[UNINTELLIGIBLE] + +back of the envelope calcuation +you can do, you + +realize how much code you need +to feed the beast to keep it + +active otherwise. + +So first loop optimization, +loop and + +invariant code motion. + +So normally in a loop you run +millions of times, and if you + +do the same thing millions of +times and get the same results + +you are just doing useless +computation. + +And so here the key thing is +most of the time the compiler, + +a good compiler will +come help you. + +So in this class you're +not trying + +to replace the compiler. + +We, as humans, we want to the +least amount of work. + +The compilers [UNINTELLIGIBLE] +dumb things sitting in there, + +it can do most of +the hard work. + +The key thing is first +trying to get the + +compiler to do the work. + +Only do things yourself if +the compiler cannot do. + +So most of the time compiler, +if it can analyze the code, + +and prove the results are the +same in each iteration, it's + +going to get rid of it, it +will do that for you. + +But there are cases it's not +possible because sometimes the + +computation might be too costly +and also there might be + +cases the computation is too +cheap if you hoist it out, you + +have to keep the results in +some [UNINTELLIGIBLE] + +and if you keep too many things +in too many registers, + +that cost might be +too expensive. + +So there might be case that you +might not do, but most of + +the time what happens +because the + +compiler can't do anything. + +So here's a good example. + +I'm doing, I don't know why I +did that, but square root and + +take exponential off that. + +Compiler look at that +as functions. + +I have no idea what the function +are most of the time. + +The compiler can't tell what +each function does because the + +function call. + +It can do any arbitrary thing as +far as the compiler knows. + +It says, OK, function call, +I don't know what happened + +inside so I'm just giving up and +I'm just leaving it, but + +you, on the other hand, knows +that the square root function, + +exponential function doesn't +have any what you call the + +side effects. + +That means those functions +doesn't go + +changing anything else. + +It just calculates +[UNINTELLIGIBLE] the value, + +you'll know this basically +calculate the same value again + +and again and you can just +basically take it out, do it + +twice, happy. + +So lot of times make sure +the compiler can do it. + +If the compiler cannot do then +you have to go in and + +interfere at that point. + +So here's another interesting +thing the compilers cannot do. + +A lot of times you're going +through this array or data + +structure looking +for some value. + +OK, once you've found the value, +you will say OK, found + +it, I return. + +OK. + +Normally what that means is when +you're going to add it, + +there's two things. + +First of all you had to test +whether you found the value + +that you're trying to exit. + +Second, you have to make sure +that you don't overrun on the + +data structure, you're +not overrunning that. + +you have to make sure you're not +at the end of that because + +that value might not +be in that area. + +If that's the case, you run +to the end of that. + +So pretend I don't find it. + +So you do two tests. + +One thing you can do is you +start doing the two test at + +the end of that array, how about +you add the value you + +are testing for? + +So you know when you reach to +the end you will always find + +the value because you +added there, so you + +know it's there already. + +So by doing that you can reuse +the test by just looking for + +the value because now when it +comes to the end, you don't + +have to do anymore tests because +the value you're + +looking is already there and +you found that, you go out. + +But you should be able to add +that value to the end of that. + +So what you do is this is your +normal test that's what you're + +doing is you're, if I can get my +mouse, you're going through + +this array, looking +for a value. + +A value I return otherwise +I return minus 1 in here. + +Now I do two tests. + +I do this test to make +sure that I'm not at + +the end of the array. + +I'm [UNINTELLIGIBLE] this one. + +So, in fact, [UNINTELLIGIBLE] + +loop I just can put the two +tests next to each other so + +this is what you're doing. + +But instead of doing that one +thing I can do is put that at + +the end of the array, after +all the data that I care + +about, I can put the value I'm +looking for and then I just + +only do one test. + +I check for that value. + +So if you find the real +value in the area, at + +that point I'm done. + +Or I ran out of the array, and +after I ran out the real data + +I just found the value because +I, myself, put it there. + +And so I have to find it, and +the minute I find it, if I + +realize that's the case I say, +OK, that's the value I put and + +I [UNINTELLIGIBLE]. + +Here I have done something +which is not really good + +programming practice. + +Can anybody put your 005 +hat and say, that's bad + +programming? + +AUDIENCE: You modified +[INAUDIBLE]. + +PROFESSOR: I modified +my input array. + +I know. + +That's not that great. + +I mean if I did it really well, +if I want to make sure + +what I should have done is kept +the old value of the n + +and at the end, it back +so it looks the + +pristine thing I got. + +I mean, if I was really careful +I would have done + +that, and then my invariant that +my input array haven't + +changed would hold nicely. +because here I have mucked + +with my input array. + +So even though you are +constantly doing performance + +programming you should still +have a good eye for doing good + +correct programming and keeping +nice programming + +variants around than mucking +it all over the place. + +So if you wonder putting a new +hat in here, you should still + +have the 005 hat, at +least partially. + +What else can we do? + +A lot of times what you find +is we have these loops, and + +loops have a couple +of features. + +First of all, you have to keep +checking the loop condition, + +that's expensive. + +And if the loop body is very +small, the compiler doesn't + +have that much opportunity to +do anything useful in the + +body, just basically +compile as is. + +So one thing you want to do is +if the loop bodies are too + +small and the number of +iterations is small, you want + +to unroll the loop. + +So in here, instead of doing +this calculation again and + +again, I want to actually do a +computation unrolled, and this + +gives you two things. + +First of all I get rid of +this disk, so I actually + +[UNINTELLIGIBLE] in here. + +And second, this computation can +be done much faster, the + +compiler can do this much +faster than this one. + +Do you see why? + +Can anybody see why this +computation would happen much + +faster than this doing in +the loop iteration? + +AUDIENCE: Because you don't have +to write the final result + +of the variable until all +the numbers [INAUDIBLE]? + +PROFESSOR: So that's +one thing. + +Even the final results in the +register what happens in here? + +So that's a good assertion +but that's not + +exactly what's back there. + +AUDIENCE: [INAUDIBLE]. + +PROFESSOR: OK, he got 90% +of the way there. + +First of all here I +had increment i. + +And I have it check +[UNINTELLIGIBLE] + +the loop condition. + +That's another point in here. + +AUDIENCE: [INAUDIBLE]. + +PROFESSOR: The one on right +can be run in parallel. + +In here I am doing +sum equals-- + +some plus A I, so that means +I have to calculate + +[UNINTELLIGIBLE]. + +Once that is done and we get the +results only then I can go + +add the two, only then +I can add day three. + +So the last [UNINTELLIGIBLE] + +using, you can show 16 +instructions at every cycle. + +OK what six things you +can do in here? + +Nothing. + +Because you're just waiting. + +You're twiddling your thumb for +the first one to finish, + +to do that. + +In here, you can say, look, I +don't have to add A1A to it. + +I can just do these things +in parallel. + +The first cycle I can +add is 0 to A of 1. + +that's one instruction +2 3 2 4 5 3 6 7. + +I can add all those things +together as a tree. + +I can do tree addition instead +of one after another, that can + +happen in one go. + +And I can get a six editions +done and then the next + +instruction I add the +[UNINTELLIGIBLE] and at the + +later stages do not have too +much to do but I could get a + +lot of [UNINTELLIGIBLE]. + +So the compiler can actually +[UNINTELLIGIBLE] + +all of that. + +So that works very nicely if +I have small number of + +iterations. + +But if you have a large number +of iterations, you can still + +do some stuff. + +So in here what you can do is +it goes to one and you can + +say, OK, I don't know. + +I don't know how to unroll fully +because I don't know + +what n is, but I can +unroll partially. + +So here what I can do is say, +look, I have been running it n + +times, I will unroll +my loop four times. + +OK. + +So I at least get enough +of unrolling here. + +That way you can choose. + +That is, you unroll enough that +the meshing can get busy. + +It's not just crawling. + +And then I haven't blown up my +code like crazy in here. + +And of course you had to clean +up and then you have to know + +how many full iterations. + +So how do you choose +how much to unroll? + +What impacts my number +of unrolls? + +I unroll four times. + +You can get greedy, and say, I'm +going to unroll 8 times, + +16, 32, 64, 128. + +Because a lot of time these are +not zero-sum some gains. + +Some stuff impact +some other way. + +So what should I use normally +for my amount of + +iterations to unroll? + +Anybody want to take +a guess what helps? + +AUDIENCE: It's probably the +number [UNINTELLIGIBLE]. + +PROFESSOR: OK, so in one sense +you can look and say number of + +instructions I can execute in +one cycle, that's a good thing + +to keep, unroll enough to +keep the process of + +[UNINTELLIGIBLE] most +of the time. + +But sometimes we can say oh +that's hard to figure that one + +out, I don't know that because +I'm at the compiler. + +I'm at high level. + +I don't know what happens +at low level. + +I'm going to unroll +1,000 times. + +So why shouldn't I unroll +a huge amount? + +What happens if I +unroll too much? + +AUDIENCE: [INAUDIBLE]. + +PROFESSOR: You might-- + +AUDIENCE: You might +to be [INAUDIBLE]. + +PROFESSOR: OK, define +it more closely. + +What do you mean? + +AUDIENCE: Perhaps there's +some [UNINTELLIGIBLE]. + +PROFESSOR: That's the one +interesting thing. + +Assume your number +of iterations + +are not always millions. + +Sometimes you might +[UNINTELLIGIBLE] + +hundred times, or 200 times. + +So if you unroll 500 times, +you would never get to the + +unroll loop. + +You end up in this +clean up loop. + +And so clean up loop, of course, +is not unrolled and so + +you're back to your +square one. + +And so a lot of times if you +unroll too much and if your + +number of iterations doesn't +fit so you end up in here, + +that's not good. + +Another thing is when you unroll +loop here there's a + +huge amount of instructions +now. + +That instructions might be too +much, it might not fit in the + +cache, it might just overwhelm +the memory system. + +So you have already now created +a loop that doesn't + +fit in the instruction cache +and that's not good either. + +So that will limit down roll, so +don't get too greedy, just + +sometimes these are the things +you kind of play with in the + +problems you're looking +at and some of it is + +architecture dependent. + +Some of them are things like +too much unroll where the + +number of iterations not that +high is problem dependent. + +Another thing you can do there +are many places if you have + +two different very same looking +loops we can put them + +together into one loop and that +gives [UNINTELLIGIBLE] + +all the loop tests and stuff +and also the array access. + +At least done once, so +that can give you + +a benefit in here. + +Here's interesting one. + +Here you have this weird loop +that the j loop run from I to + +J in minus I, I to n minus I. +How can I improve this one? + +Can anybody tell me what +might happen in here? + +So I have outer loop I goes from +0 to N, inner loop goes + +from I to N minus +I. What happen? + +Somebody's getting it. + +OK. + +AUDIENCE: [INAUDIBLE]. + +PROFESSOR: Yes, what happens is +because what the loop is at + +the beginning you're going from +basically 0 to N, and + +then the lower bound is going +like this, upper bound is + +going like this. + +After N over 2, this is +N, N over 2, there's + +no iterations left. + +OK, you're trading and trading +and trading and after it + +iterates, so you're running +outer loop, N over 2 to end + +with nothing running +on the inner loop. + +And so if you have this kind +of funky loops you can just + +look at it a little bit careful +and say, wait a + +minute, that's not useful. + +So therefore I can just get rid +of this new situations. + +And then sort of free +trading to nothing. + +So that's loops rules. + +Loops are very important. + +also you can do a lot of +interesting logic rules. + +So first of all, can anybody +shout out what each of these + +things can be done? + +Square root of x +greater than 0. + +Square of [UNINTELLIGIBLE] + +zero, sorry. + +x [UNINTELLIGIBLE]. + +Actually, not [UNINTELLIGIBLE] + +sorry. + +x not equal to zero. + +Because x squared of +x squared non-zero. + +OK. + +Here's something your compiler +probably doesn't know about + +the transformation. + +We can do that. + +How about the next one? + +How can I get to input +the next one? + +Square root of base climb, +looking at the distance + +between x and Y and AB. + +AUDIENCE: [INAUDIBLE]. + +PROFESSOR: Eliminate +the square root. + +It doesn't help anything you +do except do too much + +computation. + +OK, next one. + +Yeah, I can basically multiply +and then do take a one + +[UNINTELLIGIBLE] + +final one. + +AUDIENCE: [INAUDIBLE]. + +PROFESSOR: One. + +OK, and then you should go and +find that program who wrote + +that, but believe me you'll +find these kind of code + +sitting somewhere because you +didn't think through, you just + +start writing and suddenly you +have this kind of nice axiom. + +So when do that this is +something compiler can do, of + +for these kind of patterns. + +That was a stupid mistake but +a lot of other things are + +things that a compiler cannot do +but you know more than the + +compiler does. + +OK. + +Other interesting thing in +here is if you're looking + +something like [UNINTELLIGIBLE] + +increasing function- OK, let +me look at this carefully. + +OK, this is very similar to what +we talked before with the + +[INAUDIBLE] + +ending. + +So one thing you can do is I can +put the cut off at the end + +and then I don't have to take +check both the bounds and + +basically [UNINTELLIGIBLE] + +through something. + +Basically this is the +[UNINTELLIGIBLE] + +check we did done a little +bit differently. + +OK. + +And here's another interesting +thing. + +Reordering test. + +So what can you do here? + +What do I do here? + +I'm looking at is, I am looking +at two different a + +circles, see whether they +are [UNINTELLIGIBLE] + +in here. + +This is expensive test because +I had to do something in a + +square root and check +whether it's less + +than or equal to radius. + +So here's what I had to do. + +How can I make this faster? + +What's the [UNINTELLIGIBLE] +in here? + +So assume I have this bunch of +balls running around in my + +graphics program. + +I want to make sure that the +balls haven't collided. + +They are actually moving with no +collision with other balls + +and I'm doing this test. + +What's a good [UNINTELLIGIBLE] +in here? + +AUDIENCE: [INAUDIBLE]. + +PROFESSOR: So he's getting there +because most of the time + +what happens is if you're +looking at two balls collision + +most times these balls are +farther apart and if you just + +found the square around the +ball, testing these two + +squares are colliding +it's very cheap, OK? + +And then if the squares are all +happy, then and only then + +you might want to check +if actually all the + +balls are all happening. + +OK and by doing this square test +you can do very expensive + +operations in here. + +You can basically do some very +simple thing, in fact I have + +even reduced it more by just +doing first doing the x side + +and then if x is +[UNINTELLIGIBLE] + +I don't even have to check for +Y. And only if those two + +checks fail that I realize, +look, the square might be now + +there's a good chance it's +actually the color id. + +And there's a really good chance +most of the test, after + +doing the first two things, +will be done. + +You'll never have to go through +this very expensive + +operations. + +So here's something you have a +little bit of intuition on + +what's going on out there in +the problem, and use that + +intuition to look like more +work, but in reality really + +reduce the amount of work you +had to do because the test is + +very expensive. + +OK, here what I have done, OK +this is a little bit of a + +contrived example, what I want +to do is assume I have + +basically a 4 bit word +in here, OK. + +And I am checking- this would be +8 I think, so I have 8 bit + +word in here. + +OK, I'm checking whether the +8 bit word is a palindrome. + +So the way I check the word is a +palindrome is first of all I + +set up some bits in here, +bit masks, OK? + +And I have a bit mask +for the two ends. + +I said, OK, these two are same, +then these two same, + +these two same, these two same, +I just kind of go down + +the bit mask. + +Did everybody see +how this work? + +And then in these two I kind +of shift my bit mask to the + +side, these two, basically +shifting. + +So I'm checking the most two +bits are the same, the next + +two bits are the same, next two +bits are the same, going + +on [UNINTELLIGIBLE]. + +OK, so every time I do that +I have [UNINTELLIGIBLE] + +this bit mask do this operation +and stuff like that. + +Assume I am checking whether +my [UNINTELLIGIBLE] + +correctors. + +If I call this a lot of +times what can I do? + +Kind of out of the +box thinking. + +So the one thing is if I am only +looking for correctors, + +how many different correctors +are there? + +AUDIENCE: [INAUDIBLE]. + +PROFESSOR: Yeah, because all the +correctors in everything I + +look up, I have 8 bits, +two to date. + +What's two to date? + +[UNINTELLIGIBLE]. + +OK, so you have 256 +possibilities in here, OK. + +So I'm doing this to 256 why +don't I precompute and store? + +So if I just calculate for 256 +different possibilities, we + +see the palindrome or not, I +just store a bit for each of + +them, saying it's a palindrome +or not, and then my palindrome + +test is very simple. + +I just look up my look up table +and say, hey, is this a + +palindrome, no? + +Yes? + +No? + +Done. + +So if I'm doing this computation +a lot of times I + +suddenly realize I can +precompute the kind of things + +we did before. + +I am very safe, I can do that. + +So sometimes you have this +programs that has very + +complicated control structures +but when you look at this here + +you realize [UNINTELLIGIBLE] + +use multiple times in here. + +There's S1, if v S2, else S3. + +S4 again, if v S5. + +And so there re a lot of +conditions going on in here. + +And something like that you can +sometimes look at that and + +say, like OK, look, because +my conditions are simple. + +I mean in here, I only do one, +I just do that one and I will + +create the path depending +on what the + +Boolean expressions are. + +And even if you have two or +three conditions you can + +create a couple of parts +depending on that. + +So I'm replicating some +stuff, like S1 is in + +both, S4 is in both. + +So I have expanded my code a +lot, but now instead of having + +this spaghetti code that my +compiler and my architecture + +is going to stop all the time +because [UNINTELLIGIBLE] + +prediction and stuff, as +Professor Leiserson pointed + +out, can have issues. + +I created this nice single +branch, lot of code to + +execute, lot of chances for +my compiler to do a lot of + +optimization. + +I can say things like that. + +And compiler can do it most of +the time and sometimes you + +might want to help +the compiler. + +Procedure rules. + +So one interesting thing is a +lot of times when you have a + +lot of small procedure calls. + +A couple of things. + +OK, let me ask you, what's the +problem with having a lot of + +small procedure calls? + +You cause a lot of small methods +all over the place. + +What's the problem with +small methods? + +AUDIENCE: [INAUDIBLE]. + +PROFESSOR: [UNINTELLIGIBLE] + +yes, because every time you do +a method call you have to + +basically go change everything +[UNINTELLIGIBLE], put it back + +in memory, stack, and +then go do that. + +I have a basically calling +[UNINTELLIGIBLE] + +expensive part. + +OK, so if I'm doing a very +small thing your calling + +context might have a lot more +than overhead than what the + +procedure does, method does. + +What else? + +What's a more subtle thing +that can happen? + +So if you're thinking more, I'm +a compiler guy so I think + +like compilers, what would the +compiler do at this point? + +AUDIENCE: [INAUDIBLE]. + +PROFESSOR: Compiler +[UNINTELLIGIBLE] + +oops, barrier, I have no idea +what's happening in here. + +I had retrieved this +as just bit stop. + +I will do a bunch of things +above that, I will do a bunch + +things below that. + +But I can't go through that kind +of thing, so the compiler + +basically treats that as, I +can't touch that barrier. + +And that [UNINTELLIGIBLE] means +the amount of stuff that + +the compiler can do is +[UNINTELLIGIBLE]. + +So one way to do that +is basically inline. + +On a max function, it's pretty +simple to inline. + +Basically you can define a macro +that the CE front end + +will go inline for you. + +So this is simple. + +Or you can define inline method +in here and put it in + +the same file, and then we will +tell the compiler, look, + +go and try doing inline +listening, and by doing that + +we are forcing the compiler, or +telling it the ability to + +inline, and they're not only +getting rid of the overhead of + +the method calls, but also +you're letting the compiler a + +lot more opportunity to go and +do something interesting. + +So here's something you'll +find in many + +streaming type programs. + +What you do is you run through +a loop, reading through a + +bunch of data, do +some processing + +and writing it back. + +And then you want to get the +data you wrote back, read it + +again, do some processing +and write it back. + +The problem in that this one +is the first loop which + +stretches through all data. + +So by the time I'm done with the +first loop I have written + +all the data and the thing I +wrote early is probably all + +the way down in my +cache hierarchy. + +Because I wrote a huge amount +and it doesn't count it in my + +cache so it goes down, down, +down, and the next guy has to + +read it all the way +from bottom up. + +So [UNINTELLIGIBLE] + +means instead of doing that what +you can do is run for a + +small amount of data. + +So don't run the entire +data set. + +Run a small amount of data, +write it into a buffer in the + +middle that we know sit in the +cache, and the disk guys picks + +up the buffer and finish it +up and write it back. + +So by keeping the data in the +buffers what they have done is + +between these two I actually +had some nice locality. + +I can keep the data up. + +So as we go into memory systems +and stuff like that + +these kind of patterns +come up a lot. + +Ah ha. + +Tail recursion elimination. + +So here there are many functions +that the last thing + +you do is call itself. + +OK? + +This is pretty expensive because +what normally happens + +is when you call a function you +set up a calling contest, + +you do all this context +[UNINTELLIGIBLE] + +put things into the stack and +go, but you don't need to keep + +instead because you're basically +done with the + +previous guy. + +You're just calling just to +go create another stack. + +In a lot of these cases you can +reformulate the problem + +into nice loop that has +no function calls. + +So, in here, when you're doing +factorial, you can actually + +formulate the factorial in a way +that you don't have to do + +a function call. + +So a lot of times if you end +up in a situation that the + +last thing you do in some part +is the call itself and if + +you're not doing anything +afterwards, you can always end + +up in a situation where you +don't know how do that, you + +can actually convert it into +[UNINTELLIGIBLE] loop. + +And by doing this I got rid of +all my calling overhead and + +stuff that I'm just starting +a nice tight loop. + +OK? + +So if you have patterns that +look like that you can think, + +OK, look, this is nice, +I thought through + +[UNINTELLIGIBLE]. + +I got this there. + +But now I can [UNINTELLIGIBLE] +transform it to more iterative + +way of executing. + +In many cases you will find +a way of doing that. + +OK, then there are a bunch +of expression rules. + +So a lot of times you have this +computation that if you + +think carefully you can let +the preprocessor do in + +something like calculate +something like that, if I know + +what [UNINTELLIGIBLE] are, stuff +like that, I can just + +put it in as a constant and +voila I don't even have to pay + +any cost to compute it because +by the time it's compiled all + +the computing is done. + +And there are a lot of good +cases you can just get rid of + +work by giving it to +the preprocessor. + +I'm just calling sin(a) and +sin(a) twice in here, and the + +sin(a) squared I just basically, +the compiler + +probably won't know that the +sine every time you give it + +the same number, you give it +the same same input, it's a + +function, I think the compiler +doesn't know that, and this is + +something you probably have +to do for the compiler. + +Especially when you know the +function has no side effects. + +This is a little bit more funky, +so assume I do two + +similar computations, you might +want to do them together + +as a single computation that +gives the compiler more + +opportunity, but that means you +relay the function like a + +sine, cosine, s of 1 function. + +It's a little bit of funky thing +that in this list of + +interesting things to do. + +But I put it there because there +might be cases you might + +find that's interesting, like if +you're doing taking min and + +max, it might be calling +min and max separated. + +You might be able to +call it together. + +So the last set of rules +is parallelism rules. + +Of course, we are going to visit +parallelism like crazy + +in this class, but today we will +just go through some very + +high level stuff to give you a +little bit of feel for what + +can be done. + +So I have this rule, +this program. + +So what's wrong with +this program? + +Why would this program +run very slow? + +Can anybody tell me? + +Why can't, in this program, I +can't do the full utilization + +of my machine. + +The problem in this program is +every iteration until this + +condition is calculated I can't +start calculating this. + +And so every iteration I had +of it, this is finished, + +condition calculated, +and [UNINTELLIGIBLE] + +and new calculate that. + +And once that's done, you go +to the next iteration. + +We go to next iteration. + +So by doing this I can't +do too much work. + +On the other hand, if I can +unroll the loop like two times + +and have two different +conditions, now I can do this + +condition and these conditions, +and these two can + +be done in parallel and when +these two get resolved I can + +do these two operations. + +So instead of doing xmax, I'm +operating two different + +variables and at the end +I can resolve that. + +So what I'm doing is +I'm calculating + +two things in there. + +And they go to four things, +whatever, to + +keep the machine busy. + +And each of them can be +calculated independently. + +OK, so I can get parallelism +and at the end of the day I + +can do that to help when I'm +summing something or whatever. + +Do you see this? + +So to get the six instruction +issued at a time, something + +like that will give you more +abilities because there's more + +things that can run +in parallel. + +So most of the time it will be +good to see whether you can + +eliminate these kind of chains +like here xmax is a chain + +because xmax-- + +until the previous is calculated +I can't calculate + +the next one, until that so I +have this chain that until + +this is calculated I can't do +this, until this is done I + +can't do the next iteration, so +xmax is kind of keeping me + +very sequential. + +By doing that I have two +things I can calculate. + +So other interesting things is +if you are doing through this + +kind of data structure +link list. + +Sometimes if you have I believe +the bypass have + +another point that points couple +of things ahead then I + +can keep multiple of +them going on. + +So I can do sort of waiting +for the next one I can + +basically switch two elements, +do that so the next one I can + +get some parallelism in here so +I can do things like that. + +So to get some basic parallel +performance going on. + +And this is basic kind of a +little bit of a data structure + +augmentation. + +You add additional data +make it run faster. + +And you want to get all +your loops vectorized. + +That means you want to run +things like assembly + +instruction. + +If you're using 32 bits, you +want to put a couple of them + +together, run in +one SIMD unit. + +But I don't want any of +you guys to go write + +assembly to do this. + +It's going to be a big pain to +write all the SIMD assembly. + +We are not talking about +assembly but most the + +compiler, [UNINTELLIGIBLE] +compiler is somewhat + +good at doing it. + +So what this means is you're +kind of really nudge the + +compiler, look at bunch of +compiler frags to get the + +compiler to do it. + +Sometimes it's-- + +when we go more into it, we'll +figure out how we can do it + +looking at given the right flags +to compiler, sometimes + +chaining the program a +little bit makes it + +easier for the compiler. + +So sometimes just wrestling with +the compiler, that's much + +more easier, believe me, than +trying to do it by yourself. + +By doing that you can get some +interesting performance. + +And we will talk a lot more +about this coarse grain + +parallelism and we have a bunch +of lectures on that. + +Trying to figure out how to get +multicores, each core do + +something parallel, and get +all your [UNINTELLIGIBLE] + +in the machine working +for at a given time + +then only one guy. + +And so here's an interesting +situation. + +So I have this problem here. + +Can I run this parallel? + +So what I'm doing is I'm doing +these two loops and I'm adding + +all the elements of +an array to total. + +Is this parallel? + +Can I run anything or any of +these things parallel? + +Somebody says, yes, no, +whatever, what do you think? + +Take a stand. + +OK, what do you think? + +AUDIENCE: I think yes. + +PROFESSOR: Somebody +says yes, good. + +Yes, takers, no takers. + +Yes, everybody says yes. + +[UNINTELLIGIBLE] + +is parallel. + +But look at here, what happens +is previous total is needed to + +calculate the next total, so how +can I run this parallel? + +AUDIENCE: [INAUDIBLE] + +for loop jumps every two. + +PROFESSOR: OK, so she's somewhat +onto it, so let me + +show you what we can do. + +One thing you can do is instead +of calculating one + +total for each basically +column, you can + +calculate its own total. + +OK? + +So what happens is so for this +i's row, j's column. + +So for each row, so each row +gets a different total, a temp + +total, and so what that means +is you can calculate all the + +columns total separately. + +You can total all the columns, +and then total up those values + +to get the full total. + +So totalling up columns can be +done parallel because now all + +of these things can be done +parallel because it's + +totalling up two different, +multiple different values. + +So it's kind of what she said +but you do it for each row + +separately. + +And so here's something, you +made the program a little bit + +more complicated. + +Actually for a sequence it run a +little bit slower but at the + +end of the day you actually +get the program + +parallelizable. + +So a lot of times when you're +parallelizing is to also + +looking at that algorithm little +bit changes to the + +program that at the beginning +might look like you're slowing + +down the program but ending +up getting good parallel + +performance. + +So a lot of parallelism +looks like this. + +So here's the entire list of +things we talked about. + +It's out there so you can go +look at them and see if you + +understand them better. + +And I'm leaving you with this +example that I'm not going to + +have time to go through. which +is my program of a traveling + +salesman problem. + +So what you're doing is you're +looking at a way for a + +tradesman to travel to +all of the city's + +with a minimum cost. + +Of course the minimum shortest +thing is exponential algorithm + +so you don't do that. + +There's a good heuristic, that +the greedy heuristic every + +time you go to the city you go +to the cheapest city that's + +not visited and you just jump +around and that's seem to be + +pretty good heuristic. + +And so I call this up, and I +will go to the end and then + +just finish it up. + +Oops, I went too far. + +So what I did was I have eight +different stages basically, + +each stage I did some changes +and then I got this program to + +run about five times faster +than from where I started. + +So you will see at each +stage what I did. + +So this is basically out of the +menu of things I showed + +you I found an instance I can +do and in this program I got + +five times faster. + +This is more normal than the +300 [UNINTELLIGIBLE] + +I got [UNINTELLIGIBLE] + +and that's a real extreme +case, but enjoy + +looking at this code. \ No newline at end of file diff --git a/2oooMpS_3vg.txt b/2oooMpS_3vg.txt new file mode 100644 index 0000000000000000000000000000000000000000..c0243ef55695b28e6f65cdefea8f03f401072f83 --- /dev/null +++ b/2oooMpS_3vg.txt @@ -0,0 +1,13267 @@ +align:start 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very little primer on the science + + + align:start position:0% +and a very little primer on the science +and a primer on the + + align:start position:0% +and a primer on the + + + align:start position:0% +and a primer on the +policy uh this could easily take more + + align:start position:0% +policy uh this could easily take more + + + align:start position:0% +policy uh this could easily take more +than a semester but we'll do it in an + + align:start position:0% +than a semester but we'll do it in an + + + align:start position:0% +than a semester but we'll do it in an +hour and a half so + + align:start position:0% +hour and a half so + + + align:start position:0% +hour and a half so +uh what I'm going to mostly do is do + + align:start position:0% +uh what I'm going to mostly do is do + + + align:start position:0% +uh what I'm going to mostly do is do +what economists often do which is to say + + align:start position:0% +what economists often do which is to say + + + align:start position:0% +what economists often do which is to say +well let's suppose we have a zar let's + + align:start position:0% +well let's suppose we have a zar let's + + + align:start position:0% +well let's suppose we have a zar let's +suppose we have have a zar who can who + + align:start position:0% +suppose we have have a zar who can who + + + align:start position:0% +suppose we have have a zar who can who +can set policy what would the Zar do + + align:start position:0% +can set policy what would the Zar do + + + align:start position:0% +can set policy what would the Zar do +about climate let's assume it it's not + + align:start position:0% +about climate let's assume it it's not + + + align:start position:0% +about climate let's assume it it's not +it's it's a modern Zar not a denist zar + + align:start position:0% +it's it's a modern Zar not a denist zar + + + align:start position:0% +it's it's a modern Zar not a denist zar +um I'm going to argue and try to + + align:start position:0% +um I'm going to argue and try to + + + align:start position:0% +um I'm going to argue and try to +indicate to you why even for a zar this + + align:start position:0% +indicate to you why even for a zar this + + + align:start position:0% +indicate to you why even for a zar this +would be a hard problem this is the + + align:start position:0% +would be a hard problem this is the + + + align:start position:0% +would be a hard problem this is the +hardest public policy problem I've ever + + align:start position:0% +hardest public policy problem I've ever + + + align:start position:0% +hardest public policy problem I've ever +come near um + + align:start position:0% +come near um + + + align:start position:0% +come near um +so today we have AAR to Wednesday and + + align:start position:0% +so today we have AAR to Wednesday and + + + align:start position:0% +so today we have AAR to Wednesday and +Friday uh we don't it's like the real + + align:start position:0% +Friday uh we don't it's like the real + + + align:start position:0% +Friday uh we don't it's like the real +world and we will go through a + + align:start position:0% +world and we will go through a + + + align:start position:0% +world and we will go through a +negotiation in which you will be on as + + align:start position:0% +negotiation in which you will be on as + + + align:start position:0% +negotiation in which you will be on as +you know on teams we'll talk a little + + align:start position:0% +you know on teams we'll talk a little + + + align:start position:0% +you know on teams we'll talk a little +bit about that at the end because we're + + align:start position:0% +bit about that at the end because we're + + + align:start position:0% +bit about that at the end because we're +going to have to do some adjustments you + + align:start position:0% +going to have to do some adjustments you + + + align:start position:0% +going to have to do some adjustments you +all want to be rich countries you can't + + align:start position:0% +all want to be rich countries you can't + + + align:start position:0% +all want to be rich countries you can't +all be rich countries some of you have + + align:start position:0% +all be rich countries some of you have + + + align:start position:0% +all be rich countries some of you have +to be poor uh it's like life um all + + align:start position:0% +to be poor uh it's like life um all + + + align:start position:0% +to be poor uh it's like life um all +right so so let me do a a very little + + align:start position:0% +right so so let me do a a very little + + + align:start position:0% +right so so let me do a a very little +bit of background on the science and + + align:start position:0% +bit of background on the science and + + + align:start position:0% +bit of background on the science and +then talk about why it's a hard policy + + align:start position:0% +then talk about why it's a hard policy + + + align:start position:0% +then talk about why it's a hard policy +problem um + + align:start position:0% +problem um + + + align:start position:0% +problem um +you've probably seen this graph uh this + + align:start position:0% +you've probably seen this graph uh this + + + align:start position:0% +you've probably seen this graph uh this +is + + align:start position:0% +is + + + align:start position:0% +is +from uh uh NASA global temperatures are + + align:start position:0% +from uh uh NASA global temperatures are + + + align:start position:0% +from uh uh NASA global temperatures are +rising if you look if you look at the + + align:start position:0% +rising if you look if you look at the + + + align:start position:0% +rising if you look if you look at the +last few years it looks like a Slowdown + + align:start position:0% +last few years it looks like a Slowdown + + + align:start position:0% +last few years it looks like a Slowdown +this has been much debated the latest + + align:start position:0% +this has been much debated the latest + + + align:start position:0% +this has been much debated the latest +evidence suggests this is because of + + align:start position:0% +evidence suggests this is because of + + + align:start position:0% +evidence suggests this is because of +linia conditions in the Pacific which + + align:start position:0% +linia conditions in the Pacific which + + + align:start position:0% +linia conditions in the Pacific which +tend to lower the temperature um and + + align:start position:0% +tend to lower the temperature um and + + + align:start position:0% +tend to lower the temperature um and +solar radiation is at a minimum in its + + align:start position:0% +solar radiation is at a minimum in its + + + align:start position:0% +solar radiation is at a minimum in its +cycle + + align:start position:0% +cycle + + + align:start position:0% +cycle +those who follow these things closely + + align:start position:0% +those who follow these things closely + + + align:start position:0% +those who follow these things closely +expect when we go to El Nino conditions + + align:start position:0% +expect when we go to El Nino conditions + + + align:start position:0% +expect when we go to El Nino conditions +in the Pacific that we will break + + align:start position:0% +in the Pacific that we will break + + + align:start position:0% +in the Pacific that we will break +previous records nine of the 10 warmest + + align:start position:0% +previous records nine of the 10 warmest + + + align:start position:0% +previous records nine of the 10 warmest +years on record have been in this + + align:start position:0% +years on record have been in this + + + align:start position:0% +years on record have been in this +Century so if you smooth and you see + + align:start position:0% +Century so if you smooth and you see + + + align:start position:0% +Century so if you smooth and you see +there's a lot of variability year to + + align:start position:0% +there's a lot of variability year to + + + align:start position:0% +there's a lot of variability year to +year if you smooth the trend is + + align:start position:0% +year if you smooth the trend is + + + align:start position:0% +year if you smooth the trend is +reasonably + + align:start position:0% +reasonably + + + align:start position:0% +reasonably +clear that's + + align:start position:0% +clear that's + + + align:start position:0% +clear that's +data this is + + align:start position:0% +data this is + + + align:start position:0% +data this is +inference there's strong evidence backed + + align:start position:0% +inference there's strong evidence backed + + + align:start position:0% +inference there's strong evidence backed +by theory that human activity has a lot + + align:start position:0% +by theory that human activity has a lot + + + align:start position:0% +by theory that human activity has a lot +to to do with this this + + align:start position:0% +to to do with this this + + + align:start position:0% +to to do with this this +is uh Global Greenhouse emissions by gas + + align:start position:0% +is uh Global Greenhouse emissions by gas + + + align:start position:0% +is uh Global Greenhouse emissions by gas +in + + align:start position:0% +in + + + align:start position:0% +in +2004 you'll see on the right CO2 from + + align:start position:0% +2004 you'll see on the right CO2 from + + + align:start position:0% +2004 you'll see on the right CO2 from +fossil fuel use is a big contributor not + + align:start position:0% +fossil fuel use is a big contributor not + + + align:start position:0% +fossil fuel use is a big contributor not +the only + + align:start position:0% +the only + + + align:start position:0% +the only +contributor uh I think CO2 other is + + align:start position:0% +contributor uh I think CO2 other is + + + align:start position:0% +contributor uh I think CO2 other is +probably cement manufacturer this is + + align:start position:0% +probably cement manufacturer this is + + + align:start position:0% +probably cement manufacturer this is +land use deforestation biomass + + align:start position:0% +land use deforestation biomass + + + align:start position:0% +land use deforestation biomass +Agriculture and so forth methane nitrous + + align:start position:0% +Agriculture and so forth methane nitrous + + + align:start position:0% +Agriculture and so forth methane nitrous +oxide which is a a nasty Long Live gas + + align:start position:0% +oxide which is a a nasty Long Live gas + + + align:start position:0% +oxide which is a a nasty Long Live gas +largely comes from + + align:start position:0% +largely comes from + + + align:start position:0% +largely comes from +agriculture U methane comes of course + + align:start position:0% +agriculture U methane comes of course + + + align:start position:0% +agriculture U methane comes of course +from a variety of sources and then there + + align:start position:0% +from a variety of sources and then there + + + align:start position:0% +from a variety of sources and then there +are a bunch of long live very potent but + + align:start position:0% +are a bunch of long live very potent but + + + align:start position:0% +are a bunch of long live very potent but +very small very low concentration gases + + align:start position:0% +very small very low concentration gases + + + align:start position:0% +very small very low concentration gases +this is by + + align:start position:0% +this is by + + + align:start position:0% +this is by +sector and again you can see an awful + + align:start position:0% +sector and again you can see an awful + + + align:start position:0% +sector and again you can see an awful +lot of this is human activity obviously + + align:start position:0% +lot of this is human activity obviously + + + align:start position:0% +lot of this is human activity obviously +but generating electricity manufacturing + + align:start position:0% +but generating electricity manufacturing + + + align:start position:0% +but generating electricity manufacturing +transportation and again you get land + + align:start position:0% +transportation and again you get land + + + align:start position:0% +transportation and again you get land +use and Forestry so it's a it's a rain + + align:start position:0% +use and Forestry so it's a it's a rain + + + align:start position:0% +use and Forestry so it's a it's a rain +this is later data but it doesn't show + + align:start position:0% +this is later data but it doesn't show + + + align:start position:0% +this is later data but it doesn't show +it by gas + + align:start position:0% +it by gas + + + align:start position:0% +it by gas +um there are a wide variety of + + align:start position:0% +um there are a wide variety of + + + align:start position:0% +um there are a wide variety of +activities involved that that emit heat + + align:start position:0% +activities involved that that emit heat + + + align:start position:0% +activities involved that that emit heat +trapping gases + + align:start position:0% +trapping gases + + + align:start position:0% +trapping gases +um and uh again there's there's evidence + + align:start position:0% +um and uh again there's there's evidence + + + align:start position:0% +um and uh again there's there's evidence +there's theory that suggests that this + + align:start position:0% +there's theory that suggests that this + + + align:start position:0% +there's theory that suggests that this +is really a driver the changes in solar + + align:start position:0% +is really a driver the changes in solar + + + align:start position:0% +is really a driver the changes in solar +radiation the El Nino La n is not uh big + + align:start position:0% +radiation the El Nino La n is not uh big + + + align:start position:0% +radiation the El Nino La n is not uh big +enough yeah + + align:start position:0% + + + + align:start position:0% + +largely you also lose soil carbon uh if + + align:start position:0% +largely you also lose soil carbon uh if + + + align:start position:0% +largely you also lose soil carbon uh if +you if you cultivate and till the soil + + align:start position:0% +you if you cultivate and till the soil + + + align:start position:0% +you if you cultivate and till the soil +uh you'll lose you'll you'll you you'll + + align:start position:0% +uh you'll lose you'll you'll you you'll + + + align:start position:0% +uh you'll lose you'll you'll you you'll +have an effect you'll reduce what's + + align:start position:0% +have an effect you'll reduce what's + + + align:start position:0% +have an effect you'll reduce what's +stored in the soil so it's mostly + + align:start position:0% +stored in the soil so it's mostly + + + align:start position:0% +stored in the soil so it's mostly +deforestation but it can also be just + + align:start position:0% +deforestation but it can also be just + + + align:start position:0% +deforestation but it can also be just +agricultural + + align:start position:0% +agricultural + + + align:start position:0% +agricultural +practices um okay + + align:start position:0% +practices um okay + + + align:start position:0% +practices um okay +but for deforestation is crucial I'm + + align:start position:0% +but for deforestation is crucial I'm + + + align:start position:0% +but for deforestation is crucial I'm +going to we're going to talk mostly + + align:start position:0% +going to we're going to talk mostly + + + align:start position:0% +going to we're going to talk mostly +about CO2 from fossil fuels because + + align:start position:0% +about CO2 from fossil fuels because + + + align:start position:0% +about CO2 from fossil fuels because +that's where the policy action is and + + align:start position:0% +that's where the policy action is and + + + align:start position:0% +that's where the policy action is and +also + + align:start position:0% +also + + + align:start position:0% +also +deforestation um mostly + + align:start position:0% +deforestation um mostly + + + align:start position:0% +deforestation um mostly +because you can measure fossil fuel use + + align:start position:0% +because you can measure fossil fuel use + + + align:start position:0% +because you can measure fossil fuel use +relatively easily figuring out how + + align:start position:0% +relatively easily figuring out how + + + align:start position:0% +relatively easily figuring out how +agriculture generates nitrous oxide is + + align:start position:0% +agriculture generates nitrous oxide is + + + align:start position:0% +agriculture generates nitrous oxide is +harder much harder to measure but fuel + + align:start position:0% +harder much harder to measure but fuel + + + align:start position:0% +harder much harder to measure but fuel +use is rela relatively easy + + align:start position:0% +use is rela relatively easy + + + align:start position:0% +use is rela relatively easy +deforestation is relatively easy to + + align:start position:0% +deforestation is relatively easy to + + + align:start position:0% +deforestation is relatively easy to +measure so you can actually imagine + + align:start position:0% +measure so you can actually imagine + + + align:start position:0% +measure so you can actually imagine +agreements that might be enforceable so + + align:start position:0% +agreements that might be enforceable so + + + align:start position:0% +agreements that might be enforceable so +that's where the policy action is we + + align:start position:0% +that's where the policy action is we + + + align:start position:0% +that's where the policy action is we +also know whoops back we also know that + + align:start position:0% +also know whoops back we also know that + + + align:start position:0% +also know whoops back we also know that +there have been some clear impacts of + + align:start position:0% +there have been some clear impacts of + + + align:start position:0% +there have been some clear impacts of +climate change this is everybody's seen + + align:start position:0% +climate change this is everybody's seen + + + align:start position:0% +climate change this is everybody's seen +this this is a the change in sea ice in + + align:start position:0% +this this is a the change in sea ice in + + + align:start position:0% +this this is a the change in sea ice in +September of 79 to September of 2007 and + + align:start position:0% +September of 79 to September of 2007 and + + + align:start position:0% +September of 79 to September of 2007 and +obviously that continues and this is a + + align:start position:0% +obviously that continues and this is a + + + align:start position:0% +obviously that continues and this is a +projection and it can only be a + + align:start position:0% +projection and it can only be a + + + align:start position:0% +projection and it can only be a +projection for reasons I want to talk + + align:start position:0% +projection for reasons I want to talk + + + align:start position:0% +projection for reasons I want to talk +about of um days over + + align:start position:0% +about of um days over + + + align:start position:0% +about of um days over +100° and you see uh G there it gets hot + + align:start position:0% +100° and you see uh G there it gets hot + + + align:start position:0% +100° and you see uh G there it gets hot +in the desert but if in fact and the + + align:start position:0% +in the desert but if in fact and the + + + align:start position:0% +in the desert but if in fact and the +problem with this is is mainly uh human + + align:start position:0% +problem with this is is mainly uh human + + + align:start position:0% +problem with this is is mainly uh human +health people who are uh fragile in a + + align:start position:0% +health people who are uh fragile in a + + + align:start position:0% +health people who are uh fragile in a +variety of ways or who aren't air + + align:start position:0% +variety of ways or who aren't air + + + align:start position:0% +variety of ways or who aren't air +conditioned uh don't deal well with with + + align:start position:0% +conditioned uh don't deal well with with + + + align:start position:0% +conditioned uh don't deal well with with +large numbers of days over 100° it + + align:start position:0% +large numbers of days over 100° it + + + align:start position:0% +large numbers of days over 100° it +happened in Europe a couple of years ago + + align:start position:0% +happened in Europe a couple of years ago + + + align:start position:0% +happened in Europe a couple of years ago +there were a number of more than a + + align:start position:0% +there were a number of more than a + + + align:start position:0% +there were a number of more than a +number uh a fair number of deaths so + + align:start position:0% +number uh a fair number of deaths so + + + align:start position:0% +number uh a fair number of deaths so +these are obvious impacts if it gets + + align:start position:0% +these are obvious impacts if it gets + + + align:start position:0% +these are obvious impacts if it gets +warmer you have more hot days if it gets + + align:start position:0% +warmer you have more hot days if it gets + + + align:start position:0% +warmer you have more hot days if it gets +warmer the sea ice + + align:start position:0% +warmer the sea ice + + + align:start position:0% +warmer the sea ice +melts but that's a small part of the + + align:start position:0% +melts but that's a small part of the + + + align:start position:0% +melts but that's a small part of the +story is warming so why is this + + align:start position:0% +story is warming so why is this + + + align:start position:0% +story is warming so why is this +hard why is this a hard policy problem + + align:start position:0% +hard why is this a hard policy problem + + + align:start position:0% +hard why is this a hard policy problem +step reason one is the time + + align:start position:0% +step reason one is the time + + + align:start position:0% +step reason one is the time +scales and the time + + align:start position:0% +scales and the time + + + align:start position:0% +scales and the time +scales CO2 isn't doesn't come out of the + + align:start position:0% +scales CO2 isn't doesn't come out of the + + + align:start position:0% +scales CO2 isn't doesn't come out of the +atmosphere by simple exponential decay + + align:start position:0% +atmosphere by simple exponential decay + + + align:start position:0% +atmosphere by simple exponential decay +the process is complicated but if you + + align:start position:0% +the process is complicated but if you + + + align:start position:0% +the process is complicated but if you +think about a + + align:start position:0% +think about a + + + align:start position:0% +think about a +halflife you want to think about around + + align:start position:0% +halflife you want to think about around + + + align:start position:0% +halflife you want to think about around +a + + align:start position:0% +a + + + align:start position:0% +a +century if you can think of it in + + align:start position:0% +century if you can think of it in + + + align:start position:0% +century if you can think of it in +Half-Life + + align:start position:0% +Half-Life + + + align:start position:0% +Half-Life +terms not only does the stuff stay up + + align:start position:0% +terms not only does the stuff stay up + + + align:start position:0% +terms not only does the stuff stay up +there a long time but it takes a long + + align:start position:0% +there a long time but it takes a long + + + align:start position:0% +there a long time but it takes a long +time for its effects for the earth to be + + align:start position:0% +time for its effects for the earth to be + + + align:start position:0% +time for its effects for the earth to be +in + + align:start position:0% +in + + + align:start position:0% +in +equilibrium depending on you know how + + align:start position:0% +equilibrium depending on you know how + + + align:start position:0% +equilibrium depending on you know how +much Heat's coming in and and being + + align:start position:0% +much Heat's coming in and and being + + + align:start position:0% +much Heat's coming in and and being +trapped you got to warm the deep ocean + + align:start position:0% +trapped you got to warm the deep ocean + + + align:start position:0% +trapped you got to warm the deep ocean +the deep ocean is deep heat diffuses + + align:start position:0% +the deep ocean is deep heat diffuses + + + align:start position:0% +the deep ocean is deep heat diffuses +slowly so it's a it takes a while to + + align:start position:0% +slowly so it's a it takes a while to + + + align:start position:0% +slowly so it's a it takes a while to +warm so we're not an equilibrium now and + + align:start position:0% +warm so we're not an equilibrium now and + + + align:start position:0% +warm so we're not an equilibrium now and +the question of how far out of + + align:start position:0% +the question of how far out of + + + align:start position:0% +the question of how far out of +equilibrium we are is kind of a serious + + align:start position:0% +equilibrium we are is kind of a serious + + + align:start position:0% +equilibrium we are is kind of a serious +one um so even if you cut emissions + + align:start position:0% +one um so even if you cut emissions + + + align:start position:0% +one um so even if you cut emissions +sharply now warming would + + align:start position:0% +sharply now warming would + + + align:start position:0% +sharply now warming would +continue for + + align:start position:0% +continue for + + + align:start position:0% +continue for +decades given that we're not going to + + align:start position:0% +decades given that we're not going to + + + align:start position:0% +decades given that we're not going to +cut emission + + align:start position:0% +cut emission + + + align:start position:0% +cut emission +sharply we're dealing with centuries + + align:start position:0% +sharply we're dealing with centuries + + + align:start position:0% +sharply we're dealing with centuries +and in this literature people run out to + + align:start position:0% +and in this literature people run out to + + + align:start position:0% +and in this literature people run out to +2100 and typically out Beyond 2100 in + + align:start position:0% +2100 and typically out Beyond 2100 in + + + align:start position:0% +2100 and typically out Beyond 2100 in +thinking about a variety of + + align:start position:0% +thinking about a variety of + + + align:start position:0% +thinking about a variety of +things most human problems don't have + + align:start position:0% +things most human problems don't have + + + align:start position:0% +things most human problems don't have +time scales like that it means that + + align:start position:0% +time scales like that it means that + + + align:start position:0% +time scales like that it means that +actions taken today will affect your + + align:start position:0% +actions taken today will affect your + + + align:start position:0% +actions taken today will affect your +grandchildren that's not true in most + + align:start position:0% +grandchildren that's not true in most + + + align:start position:0% +grandchildren that's not true in most +areas of policy you can do tax policy + + align:start position:0% +areas of policy you can do tax policy + + + align:start position:0% +areas of policy you can do tax policy +Lots between now and the time your + + align:start position:0% +Lots between now and the time your + + + align:start position:0% +Lots between now and the time your +grandchildren vote but CO2 it's still + + align:start position:0% +grandchildren vote but CO2 it's still + + + align:start position:0% +grandchildren vote but CO2 it's still +going to be there the CO2 emitted today + + align:start position:0% +going to be there the CO2 emitted today + + + align:start position:0% +going to be there the CO2 emitted today +will still be there in large quantity + + align:start position:0% +will still be there in large quantity + + + align:start position:0% +will still be there in large quantity +when your grandchildren are walking + + align:start position:0% +when your grandchildren are walking + + + align:start position:0% +when your grandchildren are walking +around blaming you for it so if the Zar + + align:start position:0% +around blaming you for it so if the Zar + + + align:start position:0% +around blaming you for it so if the Zar +has to if we have a climate Zar he has + + align:start position:0% +has to if we have a climate Zar he has + + + align:start position:0% +has to if we have a climate Zar he has +to think about how to treat people not + + align:start position:0% +to think about how to treat people not + + + align:start position:0% +to think about how to treat people not +yet born because actions today will + + align:start position:0% +yet born because actions today will + + + align:start position:0% +yet born because actions today will +affect people not yet + + align:start position:0% +affect people not yet + + + align:start position:0% +affect people not yet +born I mean this is a typical example + + align:start position:0% +born I mean this is a typical example + + + align:start position:0% +born I mean this is a typical example +this is somebody's somebody's story of + + align:start position:0% +this is somebody's somebody's story of + + + align:start position:0% +this is somebody's somebody's story of +what gets flooded in Florida if you get + + align:start position:0% +what gets flooded in Florida if you get + + + align:start position:0% +what gets flooded in Florida if you get +about a meter sea level rise a meter + + align:start position:0% +about a meter sea level rise a meter + + + align:start position:0% +about a meter sea level rise a meter +your sea level rise is sort of order of + + align:start position:0% +your sea level rise is sort of order of + + + align:start position:0% +your sea level rise is sort of order of +magnitude what might happen in a + + align:start position:0% +magnitude what might happen in a + + + align:start position:0% +magnitude what might happen in a +century what's it worth today to prevent + + align:start position:0% +century what's it worth today to prevent + + + align:start position:0% +century what's it worth today to prevent +that in 2 + + align:start position:0% +that in 2 + + + align:start position:0% +that in 2 +2112 uh for reference uh my mother lives + + align:start position:0% +2112 uh for reference uh my mother lives + + + align:start position:0% +2112 uh for reference uh my mother lives +there more or less so she's okay on the + + align:start position:0% +there more or less so she's okay on the + + + align:start position:0% +there more or less so she's okay on the +other hand she's 90 years old this + + align:start position:0% +other hand she's 90 years old this + + + align:start position:0% +other hand she's 90 years old this +doesn't apply to her um but it will + + align:start position:0% +doesn't apply to her um but it will + + + align:start position:0% +doesn't apply to her um but it will +apply potentially to great great + + align:start position:0% +apply potentially to great great + + + align:start position:0% +apply potentially to great great +grandchildren so + + align:start position:0% +grandchildren so + + + align:start position:0% +grandchildren so +time scales of a century or more are + + align:start position:0% +time scales of a century or more are + + + align:start position:0% +time scales of a century or more are +hard because you know you you want a + + align:start position:0% +hard because you know you you want a + + + align:start position:0% +hard because you know you you want a +discount but how do you do that this is + + align:start position:0% +discount but how do you do that this is + + + align:start position:0% +discount but how do you do that this is +a live controversy I'm not going to give + + align:start position:0% +a live controversy I'm not going to give + + + align:start position:0% +a live controversy I'm not going to give +you an answer economists have nasty + + align:start position:0% +you an answer economists have nasty + + + align:start position:0% +you an answer economists have nasty +arguments about this there are three + + align:start position:0% +arguments about this there are three + + + align:start position:0% +arguments about this there are three +ways you might want to think about + + align:start position:0% +ways you might want to think about + + + align:start position:0% +ways you might want to think about +it the obvious way to think about what + + align:start position:0% +it the obvious way to think about what + + + align:start position:0% +it the obvious way to think about what +am I going to do about a century from + + align:start position:0% +am I going to do about a century from + + + align:start position:0% +am I going to do about a century from +now is to just think about private + + align:start position:0% +now is to just think about private + + + align:start position:0% +now is to just think about private +sector well I could I could put it in a + + align:start position:0% +sector well I could I could put it in a + + + align:start position:0% +sector well I could I could put it in a +bank or I could invest in a business or + + align:start position:0% +bank or I could invest in a business or + + + align:start position:0% +bank or I could invest in a business or +I could invested in dealing with climate + + align:start position:0% +I could invested in dealing with climate + + + align:start position:0% +I could invested in dealing with climate +change I make that choice so if I I + + align:start position:0% +change I make that choice so if I I + + + align:start position:0% +change I make that choice so if I I +ought to be using the same kind of + + align:start position:0% +ought to be using the same kind of + + + align:start position:0% +ought to be using the same kind of +discounting in both decisions right + + align:start position:0% +discounting in both decisions right + + + align:start position:0% +discounting in both decisions right +because I don't want to I don't want to + + align:start position:0% +because I don't want to I don't want to + + + align:start position:0% +because I don't want to I don't want to +IM have an imbalance you missed the + + align:start position:0% +IM have an imbalance you missed the + + + align:start position:0% +IM have an imbalance you missed the +science you could have fixed it + + align:start position:0% +science you could have fixed it + + + align:start position:0% +science you could have fixed it +um this is Professor Solomon who has + + align:start position:0% +um this is Professor Solomon who has + + + align:start position:0% +um this is Professor Solomon who has +forgotten more about climate science + + align:start position:0% +forgotten more about climate science + + + align:start position:0% +forgotten more about climate science +than I could ever aspire to learn at any + + align:start position:0% +than I could ever aspire to learn at any + + + align:start position:0% +than I could ever aspire to learn at any +rate we're talking about policy and + + align:start position:0% +rate we're talking about policy and + + + align:start position:0% +rate we're talking about policy and +we're talking about discounting um and + + align:start position:0% +we're talking about discounting um and + + + align:start position:0% +we're talking about discounting um and +why why this is hard so one one school + + align:start position:0% +why why this is hard so one one school + + + align:start position:0% +why why this is hard so one one school +of + + align:start position:0% +of + + + align:start position:0% +of +thought uh says you got to use you got + + align:start position:0% +thought uh says you got to use you got + + + align:start position:0% +thought uh says you got to use you got +to use a um private sector discount + + align:start position:0% +to use a um private sector discount + + + align:start position:0% +to use a um private sector discount +rate and one reason this school of + + align:start position:0% +rate and one reason this school of + + + align:start position:0% +rate and one reason this school of +thought achieved prominence was the Army + + align:start position:0% +thought achieved prominence was the Army + + + align:start position:0% +thought achieved prominence was the Army +Corps of + + align:start position:0% +Corps of + + + align:start position:0% +Corps of +Engineers when deciding H whether or not + + align:start position:0% +Engineers when deciding H whether or not + + + align:start position:0% +Engineers when deciding H whether or not +to build dams always used a very low + + align:start position:0% +to build dams always used a very low + + + align:start position:0% +to build dams always used a very low +discount + + align:start position:0% +discount + + + align:start position:0% +discount +rate dams last a long time so if you use + + align:start position:0% +rate dams last a long time so if you use + + + align:start position:0% +rate dams last a long time so if you use +a very low discount rate Dam look pretty + + align:start position:0% +a very low discount rate Dam look pretty + + + align:start position:0% +a very low discount rate Dam look pretty +promising + + align:start position:0% +promising + + + align:start position:0% +promising +economically and it was a huge slog in + + align:start position:0% +economically and it was a huge slog in + + + align:start position:0% +economically and it was a huge slog in +the 50s and 60s to get the core of + + align:start position:0% +the 50s and 60s to get the core of + + + align:start position:0% +the 50s and 60s to get the core of +engineers to use a private sector rate + + align:start position:0% +engineers to use a private sector rate + + + align:start position:0% +engineers to use a private sector rate +to say you can build this kind of plant + + align:start position:0% +to say you can build this kind of plant + + + align:start position:0% +to say you can build this kind of plant +or you can build a dam you ought to use + + align:start position:0% +or you can build a dam you ought to use + + + align:start position:0% +or you can build a dam you ought to use +the same discount rate in both cases you + + align:start position:0% +the same discount rate in both cases you + + + align:start position:0% +the same discount rate in both cases you +ought to use a private sector rate to + + align:start position:0% +ought to use a private sector rate to + + + align:start position:0% +ought to use a private sector rate to +think about whether or not you build + + align:start position:0% +think about whether or not you build + + + align:start position:0% +think about whether or not you build +dams there's a second school of thought + + align:start position:0% +dams there's a second school of thought + + + align:start position:0% +dams there's a second school of thought +that says wait a minute this isn't + + align:start position:0% +that says wait a minute this isn't + + + align:start position:0% +that says wait a minute this isn't +really a private sector decision if you + + align:start position:0% +really a private sector decision if you + + + align:start position:0% +really a private sector decision if you +think about optimal growth Theory + + align:start position:0% +think about optimal growth Theory + + + align:start position:0% +think about optimal growth Theory +optimal growth Theory usually + + align:start position:0% +optimal growth Theory usually + + + align:start position:0% +optimal growth Theory usually +says let me not do more than wave my + + align:start position:0% +says let me not do more than wave my + + + align:start position:0% +says let me not do more than wave my +hands at that you usually says there's a + + align:start position:0% +hands at that you usually says there's a + + + align:start position:0% +hands at that you usually says there's a +there are two reasons you discount the + + align:start position:0% +there are two reasons you discount the + + + align:start position:0% +there are two reasons you discount the +future forget the private sector for the + + align:start position:0% +future forget the private sector for the + + + align:start position:0% +future forget the private sector for the +moment if you're doing everything + + align:start position:0% +moment if you're doing everything + + + align:start position:0% +moment if you're doing everything +optimally in the economy there are two + + align:start position:0% +optimally in the economy there are two + + + align:start position:0% +optimally in the economy there are two +reasons you discount the future one + + align:start position:0% +reasons you discount the future one + + + align:start position:0% +reasons you discount the future one +there might be a pure rate of time + + align:start position:0% +there might be a pure rate of time + + + align:start position:0% +there might be a pure rate of time +preference whatever that might + + align:start position:0% +preference whatever that might + + + align:start position:0% +preference whatever that might +mean and you value money you value + + align:start position:0% +mean and you value money you value + + + align:start position:0% +mean and you value money you value +benefits in the future less than + + align:start position:0% +benefits in the future less than + + + align:start position:0% +benefits in the future less than +benefits today because people people in + + align:start position:0% +benefits today because people people in + + + align:start position:0% +benefits today because people people in +the future will be + + align:start position:0% +the future will be + + + align:start position:0% +the future will be +richer and therefore being just a little + + align:start position:0% +richer and therefore being just a little + + + align:start position:0% +richer and therefore being just a little +bit quick with the hands uh uh income on + + align:start position:0% +bit quick with the hands uh uh income on + + + align:start position:0% +bit quick with the hands uh uh income on +the margin's worth less so if I were in + + align:start position:0% +the margin's worth less so if I were in + + + align:start position:0% +the margin's worth less so if I were in +the future and I were richer then a + + align:start position:0% +the future and I were richer then a + + + align:start position:0% +the future and I were richer then a +dollar's worth of benefit would be worth + + align:start position:0% +dollar's worth of benefit would be worth + + + align:start position:0% +dollar's worth of benefit would be worth +less to me then than it is now I'll take + + align:start position:0% +less to me then than it is now I'll take + + + align:start position:0% +less to me then than it is now I'll take +that into account I'll discount that + + align:start position:0% +that into account I'll discount that + + + align:start position:0% +that into account I'll discount that +second term because people will be + + align:start position:0% +second term because people will be + + + align:start position:0% +second term because people will be +wealthier says you make a judgment and + + align:start position:0% +wealthier says you make a judgment and + + + align:start position:0% +wealthier says you make a judgment and +their their formulas I won't trouble you + + align:start position:0% +their their formulas I won't trouble you + + + align:start position:0% +their their formulas I won't trouble you +their for formulas that say here's how + + align:start position:0% +their for formulas that say here's how + + + align:start position:0% +their for formulas that say here's how +you deal with that and then you you say + + align:start position:0% +you deal with that and then you you say + + + align:start position:0% +you deal with that and then you you say +well I have a preference we all have + + align:start position:0% +well I have a preference we all have + + + align:start position:0% +well I have a preference we all have +preference for today over tomorrow + + align:start position:0% +preference for today over tomorrow + + + align:start position:0% +preference for today over tomorrow +that's a pure rate of time + + align:start position:0% +that's a pure rate of time + + + align:start position:0% +that's a pure rate of time +preference the third approach that's + + align:start position:0% +preference the third approach that's + + + align:start position:0% +preference the third approach that's +come into the into the re literature + + align:start position:0% +come into the into the re literature + + + align:start position:0% +come into the into the re literature +recently says why do you have a pure + + align:start position:0% +recently says why do you have a pure + + + align:start position:0% +recently says why do you have a pure +rate of time preference what does that + + align:start position:0% +rate of time preference what does that + + + align:start position:0% +rate of time preference what does that +mean that discriminates between + + align:start position:0% +mean that discriminates between + + + align:start position:0% +mean that discriminates between +Generations a pure rate of time + + align:start position:0% +Generations a pure rate of time + + + align:start position:0% +Generations a pure rate of time +preference says even if my grandchildren + + align:start position:0% +preference says even if my grandchildren + + + align:start position:0% +preference says even if my grandchildren +are rich are no richer than I am + + align:start position:0% +are rich are no richer than I am + + + align:start position:0% +are rich are no richer than I am +uh I'm going to value a dollar to them + + align:start position:0% +uh I'm going to value a dollar to them + + + align:start position:0% +uh I'm going to value a dollar to them +less than a dollar to + + align:start position:0% +less than a dollar to + + + align:start position:0% +less than a dollar to +me that doesn't make moral + + align:start position:0% +me that doesn't make moral + + + align:start position:0% +me that doesn't make moral +sense so IID use a zero rate of pure + + align:start position:0% +sense so IID use a zero rate of pure + + + align:start position:0% +sense so IID use a zero rate of pure +time preference and then make a judgment + + align:start position:0% +time preference and then make a judgment + + + align:start position:0% +time preference and then make a judgment +if I if I can if I want to about how + + align:start position:0% +if I if I can if I want to about how + + + align:start position:0% +if I if I can if I want to about how +much richer they will be and how much + + align:start position:0% +much richer they will be and how much + + + align:start position:0% +much richer they will be and how much +that ought to matter when I think about + + align:start position:0% +that ought to matter when I think about + + + align:start position:0% +that ought to matter when I think about +benefits now I I I present this + + align:start position:0% +benefits now I I I present this + + + align:start position:0% +benefits now I I I present this +not those are very different + + align:start position:0% +not those are very different + + + align:start position:0% +not those are very different +positions and they have very different + + align:start position:0% +positions and they have very different + + + align:start position:0% +positions and they have very different +implications for how you think about the + + align:start position:0% +implications for how you think about the + + + align:start position:0% +implications for how you think about the +future and I have to tell you depending + + align:start position:0% +future and I have to tell you depending + + + align:start position:0% +future and I have to tell you depending +on on the day of the week and the + + align:start position:0% +on on the day of the week and the + + + align:start position:0% +on on the day of the week and the +weather I I myself vacillate but let me + + align:start position:0% +weather I I myself vacillate but let me + + + align:start position:0% +weather I I myself vacillate but let me +let me just give you the um the + + align:start position:0% +let me just give you the um the + + + align:start position:0% +let me just give you the um the +implications let's take rates to + + align:start position:0% +implications let's take rates to + + + align:start position:0% +implications let's take rates to +illustrate these 7% and 3% are used in + + align:start position:0% +illustrate these 7% and 3% are used in + + + align:start position:0% +illustrate these 7% and 3% are used in +federal government decision- making the + + align:start position:0% +federal government decision- making the + + + align:start position:0% +federal government decision- making the +7% you might think of as like a private + + align:start position:0% +7% you might think of as like a private + + + align:start position:0% +7% you might think of as like a private +sector rate the 3% gets down to that + + align:start position:0% +sector rate the 3% gets down to that + + + align:start position:0% +sector rate the 3% gets down to that +second category it's a pure rate of time + + align:start position:0% +second category it's a pure rate of time + + + align:start position:0% +second category it's a pure rate of time +preference plus an adjustment and and + + align:start position:0% +preference plus an adjustment and and + + + align:start position:0% +preference plus an adjustment and and +the um + + align:start position:0% +the um + + + align:start position:0% +the um +1% was used in an influential report on + + align:start position:0% +1% was used in an influential report on + + + align:start position:0% +1% was used in an influential report on +climate change that takes the third + + align:start position:0% +climate change that takes the third + + + align:start position:0% +climate change that takes the third +position no pure rate of time preference + + align:start position:0% +position no pure rate of time preference + + + align:start position:0% +position no pure rate of time preference +no discrimination between + + align:start position:0% +no discrimination between + + + align:start position:0% +no discrimination between +Generations so let's let's uh apply that + + align:start position:0% +Generations so let's let's uh apply that + + + align:start position:0% +Generations so let's let's uh apply that +to a million dollars in 100 + + align:start position:0% +to a million dollars in 100 + + + align:start position:0% +to a million dollars in 100 +years all right if I use 1% that million + + align:start position:0% +years all right if I use 1% that million + + + align:start position:0% +years all right if I use 1% that million +dollars in 100 years is worth 368 + + align:start position:0% +dollars in 100 years is worth 368 + + + align:start position:0% +dollars in 100 years is worth 368 +$8,000 so I'd spend a fair amount + + align:start position:0% +$8,000 so I'd spend a fair amount + + + align:start position:0% +$8,000 so I'd spend a fair amount +wouldn't spend a million today but I'd + + align:start position:0% +wouldn't spend a million today but I'd + + + align:start position:0% +wouldn't spend a million today but I'd +spend a fair amount to avoid a million + + align:start position:0% +spend a fair amount to avoid a million + + + align:start position:0% +spend a fair amount to avoid a million +dollar worth of + + align:start position:0% + + + + align:start position:0% + +Damages + + align:start position:0% +Damages + + + align:start position:0% +Damages +3% woo I wouldn't spend very much at all + + align:start position:0% +3% woo I wouldn't spend very much at all + + + align:start position:0% +3% woo I wouldn't spend very much at all +to avoid a million dollars worth of + + align:start position:0% +to avoid a million dollars worth of + + + align:start position:0% +to avoid a million dollars worth of +Damages and at + + align:start position:0% +Damages and at + + + align:start position:0% +Damages and at +7% we get what a guy who used to work + + align:start position:0% +7% we get what a guy who used to work + + + align:start position:0% +7% we get what a guy who used to work +for me called the magic ray gun you let + + align:start position:0% +for me called the magic ray gun you let + + + align:start position:0% +for me called the magic ray gun you let +me discount anything at 7% + + align:start position:0% +me discount anything at 7% + + + align:start position:0% +me discount anything at 7% +in the future it goes away it's it's a + + align:start position:0% +in the future it goes away it's it's a + + + align:start position:0% +in the future it goes away it's it's a +it's it's a + + align:start position:0% +it's it's a + + + align:start position:0% +it's it's a +disappearing disappearing function I + + align:start position:0% +disappearing disappearing function I + + + align:start position:0% +disappearing disappearing function I +would spend $9,000 today to avoid a + + align:start position:0% +would spend $9,000 today to avoid a + + + align:start position:0% +would spend $9,000 today to avoid a +million dollar worth of Damages in a 100 + + align:start position:0% +million dollar worth of Damages in a 100 + + + align:start position:0% +million dollar worth of Damages in a 100 +years if I use that discount rate it + + align:start position:0% +years if I use that discount rate it + + + align:start position:0% +years if I use that discount rate it +matters a lot it matters a + + align:start position:0% +matters a lot it matters a + + + align:start position:0% +matters a lot it matters a +lot and there's no easy way to decide I + + align:start position:0% +lot and there's no easy way to decide I + + + align:start position:0% +lot and there's no easy way to decide I +think to decide among these views if you + + align:start position:0% +think to decide among these views if you + + + align:start position:0% +think to decide among these views if you +scratch most economists they come down + + align:start position:0% +scratch most economists they come down + + + align:start position:0% +scratch most economists they come down +here at 3% + + align:start position:0% +here at 3% + + + align:start position:0% +here at 3% +say but if you ask them well wait a + + align:start position:0% +say but if you ask them well wait a + + + align:start position:0% +say but if you ask them well wait a +minute aren't you crowding out private + + align:start position:0% +minute aren't you crowding out private + + + align:start position:0% +minute aren't you crowding out private +Investments they say oh well maybe maybe + + align:start position:0% +Investments they say oh well maybe maybe + + + align:start position:0% +Investments they say oh well maybe maybe +not and if you ask them well why are you + + align:start position:0% +not and if you ask them well why are you + + + align:start position:0% +not and if you ask them well why are you +discriminating against future + + align:start position:0% +discriminating against future + + + align:start position:0% +discriminating against future +generations with this pure rate of time + + align:start position:0% +generations with this pure rate of time + + + align:start position:0% +generations with this pure rate of time +preference where does that come + + align:start position:0% +preference where does that come + + + align:start position:0% +preference where does that come +from uh most people go well yeah that's + + align:start position:0% +from uh most people go well yeah that's + + + align:start position:0% +from uh most people go well yeah that's +a point so uh you can make Arguments for + + align:start position:0% +a point so uh you can make Arguments for + + + align:start position:0% +a point so uh you can make Arguments for +all three of these and they have very + + align:start position:0% +all three of these and they have very + + + align:start position:0% +all three of these and they have very +different implications the Zar will have + + align:start position:0% +different implications the Zar will have + + + align:start position:0% +different implications the Zar will have +to choose is this see the issue I hope + + align:start position:0% +to choose is this see the issue I hope + + + align:start position:0% +to choose is this see the issue I hope +if you're talking about five years 10 + + align:start position:0% +if you're talking about five years 10 + + + align:start position:0% +if you're talking about five years 10 +years it doesn't matter that much if + + align:start position:0% +years it doesn't matter that much if + + + align:start position:0% +years it doesn't matter that much if +you're talking about a 100 years which + + align:start position:0% +you're talking about a 100 years which + + + align:start position:0% +you're talking about a 100 years which +we are here it does or + + align:start position:0% +we are here it does or + + + align:start position:0% +we are here it does or +more + + align:start position:0% +more + + + align:start position:0% +more +okay that's + + align:start position:0% +okay that's + + + align:start position:0% +okay that's +hard and it's hard for the Zar it's not + + align:start position:0% +hard and it's hard for the Zar it's not + + + align:start position:0% +hard and it's hard for the Zar it's not +just hard + + align:start position:0% +just hard + + + align:start position:0% +just hard +politically I think the reason so that's + + align:start position:0% +politically I think the reason so that's + + + align:start position:0% +politically I think the reason so that's +one reason why it's hard the Zar is + + align:start position:0% +one reason why it's hard the Zar is + + + align:start position:0% +one reason why it's hard the Zar is +willing to make sacrifices today for + + align:start position:0% +willing to make sacrifices today for + + + align:start position:0% +willing to make sacrifices today for +gener ations not yet B born or even + + align:start position:0% +gener ations not yet B born or even + + + align:start position:0% +gener ations not yet B born or even +thought + + align:start position:0% +thought + + + align:start position:0% +thought +of many other people who aren't as + + align:start position:0% +of many other people who aren't as + + + align:start position:0% +of many other people who aren't as +farsighted as the are may have trouble + + align:start position:0% +farsighted as the are may have trouble + + + align:start position:0% +farsighted as the are may have trouble +doing that or voting to do that that's a + + align:start position:0% +doing that or voting to do that that's a + + + align:start position:0% +doing that or voting to do that that's a +tough that's a tough trade-off right we + + align:start position:0% +tough that's a tough trade-off right we + + + align:start position:0% +tough that's a tough trade-off right we +could reduce emissions today sharply and + + align:start position:0% +could reduce emissions today sharply and + + + align:start position:0% +could reduce emissions today sharply and +it wouldn't make any it wouldn't make + + align:start position:0% +it wouldn't make any it wouldn't make + + + align:start position:0% +it wouldn't make any it wouldn't make +much difference to us might not make + + align:start position:0% +much difference to us might not make + + + align:start position:0% +much difference to us might not make +much difference to us might make some + + align:start position:0% +much difference to us might make some + + + align:start position:0% +much difference to us might make some +difference to our children might make a + + align:start position:0% +difference to our children might make a + + + align:start position:0% +difference to our children might make a +lot of difference to their children you + + align:start position:0% +lot of difference to their children you + + + align:start position:0% +lot of difference to their children you +can't even imagine having grandchildren + + align:start position:0% +can't even imagine having grandchildren + + + align:start position:0% +can't even imagine having grandchildren +at this point right am I right I hope uh + + align:start position:0% +at this point right am I right I hope uh + + + align:start position:0% +at this point right am I right I hope uh +uh but you + + align:start position:0% +uh but you + + + align:start position:0% +uh but you +will and so will + + align:start position:0% +will and so will + + + align:start position:0% +will and so will +they okay that's one reason why it's + + align:start position:0% +they okay that's one reason why it's + + + align:start position:0% +they okay that's one reason why it's +hard because it's hard to think in terms + + align:start position:0% +hard because it's hard to think in terms + + + align:start position:0% +hard because it's hard to think in terms +of a century when you're making + + align:start position:0% +of a century when you're making + + + align:start position:0% +of a century when you're making +decisions today or + + align:start position:0% +decisions today or + + + align:start position:0% +decisions today or +more a second reason why this is hard + + align:start position:0% +more a second reason why this is hard + + + align:start position:0% +more a second reason why this is hard +even for thear is + + align:start position:0% + + + + align:start position:0% + +uncertainty + + align:start position:0% +uncertainty + + + align:start position:0% +uncertainty +and one of the one of the things + + align:start position:0% +and one of the one of the things + + + align:start position:0% +and one of the one of the things +Professor Solomon and I have learned is + + align:start position:0% +Professor Solomon and I have learned is + + + align:start position:0% +Professor Solomon and I have learned is +you can't say uncertain in public + + align:start position:0% +you can't say uncertain in public + + + align:start position:0% +you can't say uncertain in public +discourse because uncertain to the + + align:start position:0% +discourse because uncertain to the + + + align:start position:0% +discourse because uncertain to the +public means my God I don't have a clue + + align:start position:0% +public means my God I don't have a clue + + + align:start position:0% +public means my God I don't have a clue +what uncertain means in this context is + + align:start position:0% +what uncertain means in this context is + + + align:start position:0% +what uncertain means in this context is +I may not know the probability + + align:start position:0% +I may not know the probability + + + align:start position:0% +I may not know the probability +distribution but there is a probability + + align:start position:0% +distribution but there is a probability + + + align:start position:0% +distribution but there is a probability +distribution it's not and it's not uh uh + + align:start position:0% +distribution it's not and it's not uh uh + + + align:start position:0% +distribution it's not and it's not uh uh +infinitely spread + + align:start position:0% +infinitely spread + + + align:start position:0% +infinitely spread +out if you think about elements of + + align:start position:0% +out if you think about elements of + + + align:start position:0% +out if you think about elements of +uncertainty what will the atmosphere + + align:start position:0% +uncertainty what will the atmosphere + + + align:start position:0% +uncertainty what will the atmosphere +look like in a hundred years if we don't + + align:start position:0% +look like in a hundred years if we don't + + + align:start position:0% +look like in a hundred years if we don't +do anything well you know that depends + + align:start position:0% +do anything well you know that depends + + + align:start position:0% +do anything well you know that depends +on population does China collapse does + + align:start position:0% +on population does China collapse does + + + align:start position:0% +on population does China collapse does +China not collapse it depends on future + + align:start position:0% +China not collapse it depends on future + + + align:start position:0% +China not collapse it depends on future +economic growth it depends on the mix of + + align:start position:0% +economic growth it depends on the mix of + + + align:start position:0% +economic growth it depends on the mix of +activity what happens to manufacturing + + align:start position:0% +activity what happens to manufacturing + + + align:start position:0% +activity what happens to manufacturing +versus Services it depends on new + + align:start position:0% +versus Services it depends on new + + + align:start position:0% +versus Services it depends on new +technologies somebody comes up with + + align:start position:0% +technologies somebody comes up with + + + align:start position:0% +technologies somebody comes up with +cheap storage the world moves to solar + + align:start position:0% +cheap storage the world moves to solar + + + align:start position:0% +cheap storage the world moves to solar +power it's a very different + + align:start position:0% +power it's a very different + + + align:start position:0% +power it's a very different +world um than if that doesn't happen + + align:start position:0% +world um than if that doesn't happen + + + align:start position:0% +world um than if that doesn't happen +those are all big uncertainties so we + + align:start position:0% +those are all big uncertainties so we + + + align:start position:0% +those are all big uncertainties so we +don't really know what emissions will + + align:start position:0% +don't really know what emissions will + + + align:start position:0% +don't really know what emissions will +look + + align:start position:0% + + + + align:start position:0% + +like there are uncertainties about the + + align:start position:0% +like there are uncertainties about the + + + align:start position:0% +like there are uncertainties about the +climate system serious uncertainties + + align:start position:0% +climate system serious uncertainties + + + align:start position:0% +climate system serious uncertainties +about the climate system not that we + + align:start position:0% +about the climate system not that we + + + align:start position:0% +about the climate system not that we +don't know anything but as I mentioned + + align:start position:0% +don't know anything but as I mentioned + + + align:start position:0% +don't know anything but as I mentioned +there's this issue of how fast will the + + align:start position:0% +there's this issue of how fast will the + + + align:start position:0% +there's this issue of how fast will the +deep ocean warm there issues of + + align:start position:0% +deep ocean warm there issues of + + + align:start position:0% +deep ocean warm there issues of +irreversibilities and tipping points + + align:start position:0% +irreversibilities and tipping points + + + align:start position:0% +irreversibilities and tipping points +potentially did you want to talk about + + align:start position:0% +potentially did you want to talk about + + + align:start position:0% +potentially did you want to talk about +that and say a word about some of these + + align:start position:0% +that and say a word about some of these + + + align:start position:0% +that and say a word about some of these +uncertainties can I can I provoke you + + align:start position:0% +uncertainties can I can I provoke you + + + align:start position:0% +uncertainties can I can I provoke you +into a + + align:start position:0% +into a + + + align:start position:0% +into a +comment + + align:start position:0% +comment + + + align:start position:0% +comment +um possibly I guess I'm not quite sure + + align:start position:0% +um possibly I guess I'm not quite sure + + + align:start position:0% +um possibly I guess I'm not quite sure +where you want to go with it oh I just + + align:start position:0% +where you want to go with it oh I just + + + align:start position:0% +where you want to go with it oh I just +want to uh some uh some illustrative + + align:start position:0% +want to uh some uh some illustrative + + + align:start position:0% +want to uh some uh some illustrative +detail or some examples of things that + + align:start position:0% +detail or some examples of things that + + + align:start position:0% +detail or some examples of things that +might be a a concern or that might be + + align:start position:0% +might be a a concern or that might be + + + align:start position:0% +might be a a concern or that might be +nonlinearities or that might be like + + align:start position:0% +nonlinearities or that might be like + + + align:start position:0% +nonlinearities or that might be like +falling off a + + align:start position:0% +falling off a + + + align:start position:0% +falling off a +table + + align:start position:0% + + + + align:start position:0% + +okay you want to take a second just take + + align:start position:0% +okay you want to take a second just take + + + align:start position:0% +okay you want to take a second just take +a second put I hate to wa waste of + + align:start position:0% +a second put I hate to wa waste of + + + align:start position:0% +a second put I hate to wa waste of +resource I I'll do my best um you know + + align:start position:0% +resource I I'll do my best um you know + + + align:start position:0% +resource I I'll do my best um you know +th this this issue of tipping points in + + align:start position:0% +th this this issue of tipping points in + + + align:start position:0% +th this this issue of tipping points in +my mind is actually a lot more difficult + + align:start position:0% +my mind is actually a lot more difficult + + + align:start position:0% +my mind is actually a lot more difficult +than the issue of of irreversibility the + + align:start position:0% +than the issue of of irreversibility the + + + align:start position:0% +than the issue of of irreversibility the +IR reversibility problem we can talk + + align:start position:0% +IR reversibility problem we can talk + + + align:start position:0% +IR reversibility problem we can talk +about a little bit more clearly um you + + align:start position:0% +about a little bit more clearly um you + + + align:start position:0% +about a little bit more clearly um you +know for + + align:start position:0% +know for + + + align:start position:0% +know for +example um if it were to be the case + + align:start position:0% +example um if it were to be the case + + + align:start position:0% +example um if it were to be the case +that Artic sea ice were to uh disappear + + align:start position:0% +that Artic sea ice were to uh disappear + + + align:start position:0% +that Artic sea ice were to uh disappear +you might imagine that uh that would be + + align:start position:0% +you might imagine that uh that would be + + + align:start position:0% +you might imagine that uh that would be +an irreversible process but I think + + align:start position:0% +an irreversible process but I think + + + align:start position:0% +an irreversible process but I think +we're finding more and more that it + + align:start position:0% +we're finding more and more that it + + + align:start position:0% +we're finding more and more that it +actually isn't even though we had very + + align:start position:0% +actually isn't even though we had very + + + align:start position:0% +actually isn't even though we had very +low Arctic SE ice in 2007 because we + + align:start position:0% +low Arctic SE ice in 2007 because we + + + align:start position:0% +low Arctic SE ice in 2007 because we +have such cold winter + + align:start position:0% +have such cold winter + + + align:start position:0% +have such cold winter +we have the ability to reform the sea + + align:start position:0% +we have the ability to reform the sea + + + align:start position:0% +we have the ability to reform the sea +ice because it's + + align:start position:0% +ice because it's + + + align:start position:0% +ice because it's +thin even when you have multi-year ice + + align:start position:0% +thin even when you have multi-year ice + + + align:start position:0% +thin even when you have multi-year ice +it's still relatively thin it's only a + + align:start position:0% +it's still relatively thin it's only a + + + align:start position:0% +it's still relatively thin it's only a +few years uh that matters but when we + + align:start position:0% +few years uh that matters but when we + + + align:start position:0% +few years uh that matters but when we +for example uh do something that causes + + align:start position:0% +for example uh do something that causes + + + align:start position:0% +for example uh do something that causes +a big dent in the Greenland ice sheet + + align:start position:0% +a big dent in the Greenland ice sheet + + + align:start position:0% +a big dent in the Greenland ice sheet +now you know that that truly is + + align:start position:0% +now you know that that truly is + + + align:start position:0% +now you know that that truly is +something that you could think about as + + align:start position:0% +something that you could think about as + + + align:start position:0% +something that you could think about as +irreversible it's going to take a very + + align:start position:0% +irreversible it's going to take a very + + + align:start position:0% +irreversible it's going to take a very +very long time so on human time scales + + align:start position:0% +very long time so on human time scales + + + align:start position:0% +very long time so on human time scales +it's essentially irreversible if you + + align:start position:0% +it's essentially irreversible if you + + + align:start position:0% +it's essentially irreversible if you +lose a big piece of the Greenland ice + + align:start position:0% +lose a big piece of the Greenland ice + + + align:start position:0% +lose a big piece of the Greenland ice +sheet is there a Tipping Point Beyond + + align:start position:0% +sheet is there a Tipping Point Beyond + + + align:start position:0% +sheet is there a Tipping Point Beyond +which the Greenland ice sheet might kind + + align:start position:0% +which the Greenland ice sheet might kind + + + align:start position:0% +which the Greenland ice sheet might kind +of suddenly fall apart is something + + align:start position:0% +of suddenly fall apart is something + + + align:start position:0% +of suddenly fall apart is something +that's been raised much more of a + + align:start position:0% +that's been raised much more of a + + + align:start position:0% +that's been raised much more of a +controversial issue it's + + align:start position:0% +controversial issue it's + + + align:start position:0% +controversial issue it's +conceivable but most scientists who + + align:start position:0% +conceivable but most scientists who + + + align:start position:0% +conceivable but most scientists who +study the ice would argue that it's more + + align:start position:0% +study the ice would argue that it's more + + + align:start position:0% +study the ice would argue that it's more +likely to be a slow process but it but + + align:start position:0% +likely to be a slow process but it but + + + align:start position:0% +likely to be a slow process but it but +it's possible and one of the things that + + align:start position:0% +it's possible and one of the things that + + + align:start position:0% +it's possible and one of the things that +that could be uh a Tipping Point for the + + align:start position:0% +that could be uh a Tipping Point for the + + + align:start position:0% +that could be uh a Tipping Point for the +Arctic that people have also talked + + align:start position:0% +Arctic that people have also talked + + + align:start position:0% +Arctic that people have also talked +about of course is methane release from + + align:start position:0% +about of course is methane release from + + + align:start position:0% +about of course is methane release from +um things like uh UND sea deposits of + + align:start position:0% +um things like uh UND sea deposits of + + + align:start position:0% +um things like uh UND sea deposits of +methane that are actually tied up in in + + align:start position:0% +methane that are actually tied up in in + + + align:start position:0% +methane that are actually tied up in in +uh formations called clathrates and also + + align:start position:0% +uh formations called clathrates and also + + + align:start position:0% +uh formations called clathrates and also +in permafrost which you're probably more + + align:start position:0% +in permafrost which you're probably more + + + align:start position:0% +in permafrost which you're probably more +familiar with so there there are ways to + + align:start position:0% +familiar with so there there are ways to + + + align:start position:0% +familiar with so there there are ways to +trigger things that in the Tipping Point + + align:start position:0% +trigger things that in the Tipping Point + + + align:start position:0% +trigger things that in the Tipping Point +framework usually involve ice because + + align:start position:0% +framework usually involve ice because + + + align:start position:0% +framework usually involve ice because +you know that and and you can sort of + + align:start position:0% +you know that and and you can sort of + + + align:start position:0% +you know that and and you can sort of +see why that would be it's either ice or + + align:start position:0% +see why that would be it's either ice or + + + align:start position:0% +see why that would be it's either ice or +it's not you know there's no there is no + + align:start position:0% +it's not you know there's no there is no + + + align:start position:0% +it's not you know there's no there is no +slow transition from from one to to + + align:start position:0% +slow transition from from one to to + + + align:start position:0% +slow transition from from one to to +another it's a real change of state so + + align:start position:0% +another it's a real change of state so + + + align:start position:0% +another it's a real change of state so +that's some ideas okay thank you thank + + align:start position:0% +that's some ideas okay thank you thank + + + align:start position:0% +that's some ideas okay thank you thank +you + + align:start position:0% +you + + + align:start position:0% +you +so that's hard thear has to think about + + align:start position:0% +so that's hard thear has to think about + + + align:start position:0% +so that's hard thear has to think about +those + + align:start position:0% +those + + + align:start position:0% +those +possibilities which we know something + + align:start position:0% +possibilities which we know something + + + align:start position:0% +possibilities which we know something +but we don't know we can't tell when + + align:start position:0% +but we don't know we can't tell when + + + align:start position:0% +but we don't know we can't tell when +that might occur if that might those + + align:start position:0% +that might occur if that might those + + + align:start position:0% +that might occur if that might those +things might + + align:start position:0% +things might + + + align:start position:0% +things might +occur + + align:start position:0% +occur + + + align:start position:0% +occur +even climate models models complex + + align:start position:0% +even climate models models complex + + + align:start position:0% +even climate models models complex +simulation models of the climate system + + align:start position:0% +simulation models of the climate system + + + align:start position:0% +simulation models of the climate system +and there are a number of them disagree + + align:start position:0% +and there are a number of them disagree + + + align:start position:0% +and there are a number of them disagree +on what happens + + align:start position:0% +on what happens + + + align:start position:0% +on what happens +regionally will it be wetter or + + align:start position:0% +regionally will it be wetter or + + + align:start position:0% +regionally will it be wetter or +drier well that matters a + + align:start position:0% +drier well that matters a + + + align:start position:0% +drier well that matters a +lot it matters a lot whether it'll be + + align:start position:0% +lot it matters a lot whether it'll be + + + align:start position:0% +lot it matters a lot whether it'll be +wetter or drier in particular + + align:start position:0% +wetter or drier in particular + + + align:start position:0% +wetter or drier in particular +areas um for well let me just say that + + align:start position:0% +areas um for well let me just say that + + + align:start position:0% +areas um for well let me just say that +it also we don't have good predictions + + align:start position:0% +it also we don't have good predictions + + + align:start position:0% +it also we don't have good predictions +for the impacts on Hurrican + + align:start position:0% +for the impacts on Hurrican + + + align:start position:0% +for the impacts on Hurrican +canes + + align:start position:0% +canes + + + align:start position:0% +canes +more more intense none of the above more + + align:start position:0% +more more intense none of the above more + + + align:start position:0% +more more intense none of the above more +water goes into the air because it's + + align:start position:0% +water goes into the air because it's + + + align:start position:0% +water goes into the air because it's +warmer it comes down how does it come + + align:start position:0% +warmer it comes down how does it come + + + align:start position:0% +warmer it comes down how does it come +down where does it come + + align:start position:0% +down where does it come + + + align:start position:0% +down where does it come +down very + + align:start position:0% +down very + + + align:start position:0% +down very +uncertain implications for regional + + align:start position:0% + + + + align:start position:0% + +impacts Regional impacts will take us + + align:start position:0% +impacts Regional impacts will take us + + + align:start position:0% +impacts Regional impacts will take us +into new ground particularly for + + align:start position:0% +into new ground particularly for + + + align:start position:0% +into new ground particularly for +ecosystems we don't quite know how ecos + + align:start position:0% +ecosystems we don't quite know how ecos + + + align:start position:0% +ecosystems we don't quite know how ecos +systems will respond because we haven't + + align:start position:0% +systems will respond because we haven't + + + align:start position:0% +systems will respond because we haven't +done it and it's not a it's not an easy + + align:start position:0% +done it and it's not a it's not an easy + + + align:start position:0% +done it and it's not a it's not an easy +experiment so IM damages effects like + + align:start position:0% +experiment so IM damages effects like + + + align:start position:0% +experiment so IM damages effects like +rainfall are uncertain the implications + + align:start position:0% +rainfall are uncertain the implications + + + align:start position:0% +rainfall are uncertain the implications +of those effects are also + + align:start position:0% +of those effects are also + + + align:start position:0% +of those effects are also +uncertain and + + align:start position:0% +uncertain and + + + align:start position:0% +uncertain and +finally um there's little experience in + + align:start position:0% +finally um there's little experience in + + + align:start position:0% +finally um there's little experience in +sort of how do human civilizations react + + align:start position:0% +sort of how do human civilizations react + + + align:start position:0% +sort of how do human civilizations react +to large scale environmental changes of + + align:start position:0% +to large scale environmental changes of + + + align:start position:0% +to large scale environmental changes of +various kinds I've been seeing on Google + + align:start position:0% +various kinds I've been seeing on Google + + + align:start position:0% +various kinds I've been seeing on Google +News reference to small changes in + + align:start position:0% +News reference to small changes in + + + align:start position:0% +News reference to small changes in +rainfall being the likely culprit in the + + align:start position:0% +rainfall being the likely culprit in the + + + align:start position:0% +rainfall being the likely culprit in the +downfall of the Mayas maybe 20 + + align:start position:0% +downfall of the Mayas maybe 20 + + + align:start position:0% +downfall of the Mayas maybe 20 +30% reductions not huge droughts + + align:start position:0% +30% reductions not huge droughts + + + align:start position:0% +30% reductions not huge droughts +sensitive enough are poor countries in + + align:start position:0% +sensitive enough are poor countries in + + + align:start position:0% +sensitive enough are poor countries in +the tropics that sensitive probably not + + align:start position:0% +the tropics that sensitive probably not + + + align:start position:0% +the tropics that sensitive probably not +how + + align:start position:0% +how + + + align:start position:0% +how +sensitive uh and finally the cost of + + align:start position:0% +sensitive uh and finally the cost of + + + align:start position:0% +sensitive uh and finally the cost of +emissions reductions are also + + align:start position:0% +emissions reductions are also + + + align:start position:0% +emissions reductions are also +uncertain so the Zar is going to have to + + align:start position:0% +uncertain so the Zar is going to have to + + + align:start position:0% +uncertain so the Zar is going to have to +deal with this and the Zar is going to + + align:start position:0% +deal with this and the Zar is going to + + + align:start position:0% +deal with this and the Zar is going to +have to deal with the fact that we will + + align:start position:0% +have to deal with the fact that we will + + + align:start position:0% +have to deal with the fact that we will +be learning as we go so this is I I now + + align:start position:0% +be learning as we go so this is I I now + + + align:start position:0% +be learning as we go so this is I I now +go to uh my favorite picture from the so + + align:start position:0% +go to uh my favorite picture from the so + + + align:start position:0% +go to uh my favorite picture from the so +you can't do cost benefit analysis + + align:start position:0% +you can't do cost benefit analysis + + + align:start position:0% +you can't do cost benefit analysis +because you don't know the cost and you + + align:start position:0% +because you don't know the cost and you + + + align:start position:0% +because you don't know the cost and you +don't know the + + align:start position:0% +don't know the + + + align:start position:0% +don't know the +benefits so thear can't just do the + + align:start position:0% +benefits so thear can't just do the + + + align:start position:0% +benefits so thear can't just do the +arithmetic because he doesn't know the + + align:start position:0% +arithmetic because he doesn't know the + + + align:start position:0% +arithmetic because he doesn't know the +costs or the benefits even if he could + + align:start position:0% +costs or the benefits even if he could + + + align:start position:0% +costs or the benefits even if he could +do the + + align:start position:0% +do the + + + align:start position:0% +do the +discounting a problem like this needs + + align:start position:0% +discounting a problem like this needs + + + align:start position:0% +discounting a problem like this needs +adaptive or iterative risk management + + align:start position:0% +adaptive or iterative risk management + + + align:start position:0% +adaptive or iterative risk management +and you can read that in the report of + + align:start position:0% +and you can read that in the report of + + + align:start position:0% +and you can read that in the report of +the committee on America's climate + + align:start position:0% +the committee on America's climate + + + align:start position:0% +the committee on America's climate +choices on which professor Solomon and I + + align:start position:0% +choices on which professor Solomon and I + + + align:start position:0% +choices on which professor Solomon and I +both served if you think about steering + + align:start position:0% +both served if you think about steering + + + align:start position:0% +both served if you think about steering +a ship in iceberg infested waters at + + align:start position:0% +a ship in iceberg infested waters at + + + align:start position:0% +a ship in iceberg infested waters at +night before + + align:start position:0% +night before + + + align:start position:0% +night before +radar uh I to avoid the Titanic it the + + align:start position:0% +radar uh I to avoid the Titanic it the + + + align:start position:0% +radar uh I to avoid the Titanic it the +the elements of what a sensible Skipper + + align:start position:0% +the elements of what a sensible Skipper + + + align:start position:0% +the elements of what a sensible Skipper +does are the elements of what the Zar + + align:start position:0% +does are the elements of what the Zar + + + align:start position:0% +does are the elements of what the Zar +would do to deal with climate you slow + + align:start position:0% +would do to deal with climate you slow + + + align:start position:0% +would do to deal with climate you slow +down good plan so you reduce + + align:start position:0% +down good plan so you reduce + + + align:start position:0% +down good plan so you reduce +emissions you don't quite know what the + + align:start position:0% +emissions you don't quite know what the + + + align:start position:0% +emissions you don't quite know what the +consequences are but you know more + + align:start position:0% +consequences are but you know more + + + align:start position:0% +consequences are but you know more +of of having more emissions or of going + + align:start position:0% +of of having more emissions or of going + + + align:start position:0% +of of having more emissions or of going +faster but you know they're probably not + + align:start position:0% +faster but you know they're probably not + + + align:start position:0% +faster but you know they're probably not +good on balance so you slow down you + + align:start position:0% +good on balance so you slow down you + + + align:start position:0% +good on balance so you slow down you +prepare for for something to happen you + + align:start position:0% +prepare for for something to happen you + + + align:start position:0% +prepare for for something to happen you +prepare to + + align:start position:0% +prepare to + + + align:start position:0% +prepare to +adapt you learn you station Lookouts you + + align:start position:0% +adapt you learn you station Lookouts you + + + align:start position:0% +adapt you learn you station Lookouts you +study the system you see what's going + + align:start position:0% +study the system you see what's going + + + align:start position:0% +study the system you see what's going +on you develop options new technologies + + align:start position:0% +on you develop options new technologies + + + align:start position:0% +on you develop options new technologies +geoengineering which I'll talk about + + align:start position:0% +geoengineering which I'll talk about + + + align:start position:0% +geoengineering which I'll talk about +briefly and you try to figure out a + + align:start position:0% +briefly and you try to figure out a + + + align:start position:0% +briefly and you try to figure out a +system that enables learning to affect + + align:start position:0% +system that enables learning to affect + + + align:start position:0% +system that enables learning to affect +decisions so you want to hear the + + align:start position:0% +decisions so you want to hear the + + + align:start position:0% +decisions so you want to hear the +Lookouts when they see something so + + align:start position:0% +Lookouts when they see something so + + + align:start position:0% +Lookouts when they see something so +that's the sort of thing the Zar is + + align:start position:0% +that's the sort of thing the Zar is + + + align:start position:0% +that's the sort of thing the Zar is +going to have to do because we don't + + align:start position:0% +going to have to do because we don't + + + align:start position:0% +going to have to do because we don't +know + + align:start position:0% +know + + + align:start position:0% +know +probabilities we don't know really + + align:start position:0% +probabilities we don't know really + + + align:start position:0% +probabilities we don't know really +models and studies of what's going to + + align:start position:0% +models and studies of what's going to + + + align:start position:0% +models and studies of what's going to +happen to the Greenland ice sheet but we + + align:start position:0% +happen to the Greenland ice sheet but we + + + align:start position:0% +happen to the Greenland ice sheet but we +don't know for sure we don't know for + + align:start position:0% +don't know for sure we don't know for + + + align:start position:0% +don't know for sure we don't know for +sure and we don't know for sure whether + + align:start position:0% +sure and we don't know for sure whether + + + align:start position:0% +sure and we don't know for sure whether +it's going to get wetter or drier in + + align:start position:0% +it's going to get wetter or drier in + + + align:start position:0% +it's going to get wetter or drier in +Ethiopia + + align:start position:0% + + + + align:start position:0% + +so just a word about + + align:start position:0% +so just a word about + + + align:start position:0% +so just a word about +adaptation the Zar will have to have to + + align:start position:0% +adaptation the Zar will have to have to + + + align:start position:0% +adaptation the Zar will have to have to +do some of + + align:start position:0% +do some of + + + align:start position:0% +do some of +this but as I said the small scale and + + align:start position:0% +this but as I said the small scale and + + + align:start position:0% +this but as I said the small scale and +we will adapt uh that that first line is + + align:start position:0% +we will adapt uh that that first line is + + + align:start position:0% +we will adapt uh that that first line is +one of my favorite statements about + + align:start position:0% +one of my favorite statements about + + + align:start position:0% +one of my favorite statements about +adaptation which is the default mode of + + align:start position:0% +adaptation which is the default mode of + + + align:start position:0% +adaptation which is the default mode of +adaptation is + + align:start position:0% +adaptation is + + + align:start position:0% +adaptation is +suffering so we'll adapt but the + + align:start position:0% +suffering so we'll adapt but the + + + align:start position:0% +suffering so we'll adapt but the +question is will we actually uh do any + + align:start position:0% +question is will we actually uh do any + + + align:start position:0% +question is will we actually uh do any +changes will we will we do any proactive + + align:start position:0% +changes will we will we do any proactive + + + align:start position:0% +changes will we will we do any proactive +adaptation um as I said problem one is + + align:start position:0% +adaptation um as I said problem one is + + + align:start position:0% +adaptation um as I said problem one is +that the the climate models differ and I + + align:start position:0% +that the the climate models differ and I + + + align:start position:0% +that the the climate models differ and I +will give you an example a colleague was + + align:start position:0% +will give you an example a colleague was + + + align:start position:0% +will give you an example a colleague was +called in by the government of Ethiopia + + align:start position:0% +called in by the government of Ethiopia + + + align:start position:0% +called in by the government of Ethiopia +some years ago and they said all right + + align:start position:0% +some years ago and they said all right + + + align:start position:0% +some years ago and they said all right +we believe there's going to be climate + + align:start position:0% +we believe there's going to be climate + + + align:start position:0% +we believe there's going to be climate +change what do we do half the climate + + align:start position:0% +change what do we do half the climate + + + align:start position:0% +change what do we do half the climate +models say it's going to get + + align:start position:0% +models say it's going to get + + + align:start position:0% +models say it's going to get +drier and half the climate models say + + align:start position:0% +drier and half the climate models say + + + align:start position:0% +drier and half the climate models say +it's going to get + + align:start position:0% +it's going to get + + + align:start position:0% +it's going to get +wetter how exactly do we prepare for + + align:start position:0% +wetter how exactly do we prepare for + + + align:start position:0% +wetter how exactly do we prepare for +this un certain + + align:start position:0% +this un certain + + + align:start position:0% +this un certain +future their answer was pave the + + align:start position:0% +future their answer was pave the + + + align:start position:0% +future their answer was pave the +roads because if it's drier okay you + + align:start position:0% +roads because if it's drier okay you + + + align:start position:0% +roads because if it's drier okay you +have paved roads if it's wetter a + + align:start position:0% +have paved roads if it's wetter a + + + align:start position:0% +have paved roads if it's wetter a +problem that Ethiopia traditionally has + + align:start position:0% +problem that Ethiopia traditionally has + + + align:start position:0% +problem that Ethiopia traditionally has +is that unpaved roads wash out when + + align:start position:0% +is that unpaved roads wash out when + + + align:start position:0% +is that unpaved roads wash out when +there's heavy rainfall and the whole + + align:start position:0% +there's heavy rainfall and the whole + + + align:start position:0% +there's heavy rainfall and the whole +process of getting food to Market breaks + + align:start position:0% +process of getting food to Market breaks + + + align:start position:0% +process of getting food to Market breaks +down so if it gets wetter you will + + align:start position:0% +down so if it gets wetter you will + + + align:start position:0% +down so if it gets wetter you will +really need paved + + align:start position:0% +really need paved + + + align:start position:0% +really need paved +roads and if it doesn't get wetter paved + + align:start position:0% +roads and if it doesn't get wetter paved + + + align:start position:0% +roads and if it doesn't get wetter paved +roads are not a bad thing to have + + align:start position:0% +roads are not a bad thing to have + + + align:start position:0% +roads are not a bad thing to have +they're going to be a lot of decisions + + align:start position:0% +they're going to be a lot of decisions + + + align:start position:0% +they're going to be a lot of decisions +like that a lot of people looking for + + align:start position:0% +like that a lot of people looking for + + + align:start position:0% +like that a lot of people looking for +robust policies the second problem of + + align:start position:0% +robust policies the second problem of + + + align:start position:0% +robust policies the second problem of +course is thear can't possibly make all + + align:start position:0% +course is thear can't possibly make all + + + align:start position:0% +course is thear can't possibly make all +these + + align:start position:0% +these + + + align:start position:0% +these +decisions they're going to be made at + + align:start position:0% +decisions they're going to be made at + + + align:start position:0% +decisions they're going to be made at +state and local levels a number of + + align:start position:0% +state and local levels a number of + + + align:start position:0% +state and local levels a number of +cities and states have now already and + + align:start position:0% +cities and states have now already and + + + align:start position:0% +cities and states have now already and +the US and certainly foreign countries + + align:start position:0% +the US and certainly foreign countries + + + align:start position:0% +the US and certainly foreign countries +have now processes in place to think + + align:start position:0% +have now processes in place to think + + + align:start position:0% +have now processes in place to think +about this to try to think about things + + align:start position:0% +about this to try to think about things + + + align:start position:0% +about this to try to think about things +as Ethiopia did what can we do that's + + align:start position:0% +as Ethiopia did what can we do that's + + + align:start position:0% +as Ethiopia did what can we do that's +robust if we're going to have a sea + + align:start position:0% +robust if we're going to have a sea + + + align:start position:0% +robust if we're going to have a sea +level rise how do we cope with that what + + align:start position:0% +level rise how do we cope with that what + + + align:start position:0% +level rise how do we cope with that what +do we need to do about hurricanes how do + + align:start position:0% +do we need to do about hurricanes how do + + + align:start position:0% +do we need to do about hurricanes how do +we change various policies awful lot of + + align:start position:0% +we change various policies awful lot of + + + align:start position:0% +we change various policies awful lot of +that is local awful lot of that has to + + align:start position:0% +that is local awful lot of that has to + + + align:start position:0% +that is local awful lot of that has to +be local and an awful lot of that's + + align:start position:0% +be local and an awful lot of that's + + + align:start position:0% +be local and an awful lot of that's +going to be in poor + + align:start position:0% +going to be in poor + + + align:start position:0% +going to be in poor +countries so adaptation will happen the + + align:start position:0% +countries so adaptation will happen the + + + align:start position:0% +countries so adaptation will happen the +Zar will try to do something about that + + align:start position:0% +Zar will try to do something about that + + + align:start position:0% +Zar will try to do something about that +but that one hopes is not enough or one + + align:start position:0% +but that one hopes is not enough or one + + + align:start position:0% +but that one hopes is not enough or one +doubts it will be enough to really get + + align:start position:0% +doubts it will be enough to really get + + + align:start position:0% +doubts it will be enough to really get +us smoothly new technology you guys are + + align:start position:0% +us smoothly new technology you guys are + + + align:start position:0% +us smoothly new technology you guys are +going to develop new technologies that's + + align:start position:0% +going to develop new technologies that's + + + align:start position:0% +going to develop new technologies that's +going to be terrific what's the Zar + + align:start position:0% +going to be terrific what's the Zar + + + align:start position:0% +going to be terrific what's the Zar +going to do about that well governments + + align:start position:0% +going to do about that well governments + + + align:start position:0% +going to do about that well governments +we come back to some of these issues but + + align:start position:0% +we come back to some of these issues but + + + align:start position:0% +we come back to some of these issues but +governments have a terrible record of + + align:start position:0% +governments have a terrible record of + + + align:start position:0% +governments have a terrible record of +pushing the development of Civilian + + align:start position:0% +pushing the development of Civilian + + + align:start position:0% +pushing the development of Civilian +Technologies military Technologies space + + align:start position:0% +Technologies military Technologies space + + + align:start position:0% +Technologies military Technologies space +Technologies where cost doesn't + + align:start position:0% +Technologies where cost doesn't + + + align:start position:0% +Technologies where cost doesn't +matter fine basic research fine getting + + align:start position:0% +matter fine basic research fine getting + + + align:start position:0% +matter fine basic research fine getting +stuff to Market at a reasonable price + + align:start position:0% +stuff to Market at a reasonable price + + + align:start position:0% +stuff to Market at a reasonable price +bad record so if you can't adapt and you + + align:start position:0% +bad record so if you can't adapt and you + + + align:start position:0% +bad record so if you can't adapt and you +can't solve it with + + align:start position:0% +can't solve it with + + + align:start position:0% +can't solve it with +technology um you got to reduce + + align:start position:0% +technology um you got to reduce + + + align:start position:0% +technology um you got to reduce +emissions why is reducing hard oh well + + align:start position:0% +emissions why is reducing hard oh well + + + align:start position:0% +emissions why is reducing hard oh well +let me first fossil fuels I'll just + + align:start position:0% +let me first fossil fuels I'll just + + + align:start position:0% +let me first fossil fuels I'll just +another thing you might think about + + align:start position:0% +another thing you might think about + + + align:start position:0% +another thing you might think about +doing and you've probably read about is + + align:start position:0% +doing and you've probably read about is + + + align:start position:0% +doing and you've probably read about is +geoengineering um the simplest way to + + align:start position:0% +geoengineering um the simplest way to + + + align:start position:0% +geoengineering um the simplest way to +think about that is artificial volcanoes + + align:start position:0% +think about that is artificial volcanoes + + + align:start position:0% +think about that is artificial volcanoes +you might put + + align:start position:0% +you might put + + + align:start position:0% +you might put +sulfate when Mount Pinatubo blew up uh + + align:start position:0% +sulfate when Mount Pinatubo blew up uh + + + align:start position:0% +sulfate when Mount Pinatubo blew up uh +as I understand it there was a + + align:start position:0% +as I understand it there was a + + + align:start position:0% +as I understand it there was a +discernable + + align:start position:0% +discernable + + + align:start position:0% +discernable +cooling small particles aerosols uh in + + align:start position:0% +cooling small particles aerosols uh in + + + align:start position:0% +cooling small particles aerosols uh in +the stratosphere reflect sunlight so why + + align:start position:0% +the stratosphere reflect sunlight so why + + + align:start position:0% +the stratosphere reflect sunlight so why +don't we just either burn more coal + + align:start position:0% +don't we just either burn more coal + + + align:start position:0% +don't we just either burn more coal +or take the 16-inch guns from + + align:start position:0% +or take the 16-inch guns from + + + align:start position:0% +or take the 16-inch guns from +battleships that aren't in use anymore + + align:start position:0% +battleships that aren't in use anymore + + + align:start position:0% +battleships that aren't in use anymore +turn them up and fire aerosols into the + + align:start position:0% +turn them up and fire aerosols into the + + + align:start position:0% +turn them up and fire aerosols into the +stratosphere uh this is a serious + + align:start position:0% +stratosphere uh this is a serious + + + align:start position:0% +stratosphere uh this is a serious +proposal to reflect + + align:start position:0% +proposal to reflect + + + align:start position:0% +proposal to reflect +sunlight well uh you might want to have + + align:start position:0% +sunlight well uh you might want to have + + + align:start position:0% +sunlight well uh you might want to have +that in your back pocket for emergencies + + align:start position:0% +that in your back pocket for emergencies + + + align:start position:0% +that in your back pocket for emergencies +but uh first of all if you have more CO2 + + align:start position:0% +but uh first of all if you have more CO2 + + + align:start position:0% +but uh first of all if you have more CO2 +in the atmosphere the ocean becomes more + + align:start position:0% +in the atmosphere the ocean becomes more + + + align:start position:0% +in the atmosphere the ocean becomes more +acidic and creatures die doesn't solve + + align:start position:0% +acidic and creatures die doesn't solve + + + align:start position:0% +acidic and creatures die doesn't solve +that problem and second if you don't + + align:start position:0% +that problem and second if you don't + + + align:start position:0% +that problem and second if you don't +reduce emissions you got to keep doing + + align:start position:0% +reduce emissions you got to keep doing + + + align:start position:0% +reduce emissions you got to keep doing +more and more of that and that does not + + align:start position:0% +more and more of that and that does not + + + align:start position:0% +more and more of that and that does not +sound like a long-term Way Forward so + + align:start position:0% +sound like a long-term Way Forward so + + + align:start position:0% +sound like a long-term Way Forward so +CO2 is where the policy focus is because + + align:start position:0% +CO2 is where the policy focus is because + + + align:start position:0% +CO2 is where the policy focus is because +as we saw from those earlier graphs it's + + align:start position:0% +as we saw from those earlier graphs it's + + + align:start position:0% +as we saw from those earlier graphs it's +it's quite important it lasts a long + + align:start position:0% +it's quite important it lasts a long + + + align:start position:0% +it's quite important it lasts a long +time we can measure fossil fuel use + + align:start position:0% +time we can measure fossil fuel use + + + align:start position:0% +time we can measure fossil fuel use +pretty easily think about countries that + + align:start position:0% +pretty easily think about countries that + + + align:start position:0% +pretty easily think about countries that +import all their oil + + align:start position:0% +import all their oil + + + align:start position:0% +import all their oil +um you can measure Imports pretty easily + + align:start position:0% +um you can measure Imports pretty easily + + + align:start position:0% +um you can measure Imports pretty easily +at the ports where they happen you may + + align:start position:0% +at the ports where they happen you may + + + align:start position:0% +at the ports where they happen you may +be wrong plus or minus inventory + + align:start position:0% +be wrong plus or minus inventory + + + align:start position:0% +be wrong plus or minus inventory +accumulation but it's not easy to carry + + align:start position:0% +accumulation but it's not easy to carry + + + align:start position:0% +accumulation but it's not easy to carry +in not cheap to carry inventories of + + align:start position:0% +in not cheap to carry inventories of + + + align:start position:0% +in not cheap to carry inventories of +crude oil and refined product so it's + + align:start position:0% +crude oil and refined product so it's + + + align:start position:0% +crude oil and refined product so it's +not in terms of internationally + + align:start position:0% +not in terms of internationally + + + align:start position:0% +not in terms of internationally +enforceable agreements fossil fuel is + + align:start position:0% +enforceable agreements fossil fuel is + + + align:start position:0% +enforceable agreements fossil fuel is +pretty + + align:start position:0% +pretty + + + align:start position:0% +pretty +easy compared to anything else you want + + align:start position:0% +easy compared to anything else you want + + + align:start position:0% +easy compared to anything else you want +to think + + align:start position:0% +to think + + + align:start position:0% +to think +about uh another reason you focus on it + + align:start position:0% +about uh another reason you focus on it + + + align:start position:0% +about uh another reason you focus on it +as we talked about uh last week not only + + align:start position:0% +as we talked about uh last week not only + + + align:start position:0% +as we talked about uh last week not only +does it involve durable assets that can + + align:start position:0% +does it involve durable assets that can + + + align:start position:0% +does it involve durable assets that can +last a long time that are expensive and + + align:start position:0% +last a long time that are expensive and + + + align:start position:0% +last a long time that are expensive and +thus expensive to replace + + align:start position:0% +thus expensive to replace + + + align:start position:0% +thus expensive to replace +early um but they're all these other + + align:start position:0% +early um but they're all these other + + + align:start position:0% +early um but they're all these other +path + + align:start position:0% +path + + + align:start position:0% +path +dependencies that keep you down a path + + align:start position:0% +dependencies that keep you down a path + + + align:start position:0% +dependencies that keep you down a path +so that if you want to so the energy + + align:start position:0% +so that if you want to so the energy + + + align:start position:0% +so that if you want to so the energy +system is a slow ship to turn and if you + + align:start position:0% +system is a slow ship to turn and if you + + + align:start position:0% +system is a slow ship to turn and if you +need to turn it because its impacts last + + align:start position:0% +need to turn it because its impacts last + + + align:start position:0% +need to turn it because its impacts last +100 years + + align:start position:0% +100 years + + + align:start position:0% +100 years +and if you can turn it because you can + + align:start position:0% +and if you can turn it because you can + + + align:start position:0% +and if you can turn it because you can +monitor and enforce that's a logical + + align:start position:0% +monitor and enforce that's a logical + + + align:start position:0% +monitor and enforce that's a logical +place to + + align:start position:0% + + + + align:start position:0% + +focus why is that problem hard why is it + + align:start position:0% +focus why is that problem hard why is it + + + align:start position:0% +focus why is that problem hard why is it +hard to to change emissions well we + + align:start position:0% +hard to to change emissions well we + + + align:start position:0% +hard to to change emissions well we +talked about that this + + align:start position:0% +talked about that this + + + align:start position:0% +talked about that this +is some of some colorcoded not very well + + align:start position:0% +is some of some colorcoded not very well + + + align:start position:0% +is some of some colorcoded not very well +colorcoded Emissions trajectories on the + + align:start position:0% +colorcoded Emissions trajectories on the + + + align:start position:0% +colorcoded Emissions trajectories on the +left um matched with atmospheric CO2 + + align:start position:0% +left um matched with atmospheric CO2 + + + align:start position:0% +left um matched with atmospheric CO2 +concentrations on the right and matched + + align:start position:0% +concentrations on the right and matched + + + align:start position:0% +concentrations on the right and matched +down here + + align:start position:0% +down here + + + align:start position:0% +down here +except for the really aggressive + + align:start position:0% +except for the really aggressive + + + align:start position:0% +except for the really aggressive +reduction scenario matched with uh + + align:start position:0% +reduction scenario matched with uh + + + align:start position:0% +reduction scenario matched with uh +temperature + + align:start position:0% +temperature + + + align:start position:0% +temperature +increases uh so the world runs on fossil + + align:start position:0% +increases uh so the world runs on fossil + + + align:start position:0% +increases uh so the world runs on fossil +fuels to a first approximation you saw + + align:start position:0% +fuels to a first approximation you saw + + + align:start position:0% +fuels to a first approximation you saw +all + + align:start position:0% +all + + + align:start position:0% +all +those um uh Lawrence Livermore graphs + + align:start position:0% +those um uh Lawrence Livermore graphs + + + align:start position:0% +those um uh Lawrence Livermore graphs +of sources of fuel sources of energy + + align:start position:0% +of sources of fuel sources of energy + + + align:start position:0% +of sources of fuel sources of energy +most of it's fossil the world runs on + + align:start position:0% +most of it's fossil the world runs on + + + align:start position:0% +most of it's fossil the world runs on +fossil fuels big emission cuts are + + align:start position:0% +fossil fuels big emission cuts are + + + align:start position:0% +fossil fuels big emission cuts are +needed if you're going to reduce + + align:start position:0% +needed if you're going to reduce + + + align:start position:0% +needed if you're going to reduce +temperature take the you might think of + + align:start position:0% +temperature take the you might think of + + + align:start position:0% +temperature take the you might think of +the + + align:start position:0% +the + + + align:start position:0% +the +orange kind of as an estimate of + + align:start position:0% +orange kind of as an estimate of + + + align:start position:0% +orange kind of as an estimate of +businesses usual maybe somebody's + + align:start position:0% +businesses usual maybe somebody's + + + align:start position:0% +businesses usual maybe somebody's +estimate the blue then is a pretty + + align:start position:0% +estimate the blue then is a pretty + + + align:start position:0% +estimate the blue then is a pretty +aggressive cut but look what and the + + align:start position:0% +aggressive cut but look what and the + + + align:start position:0% +aggressive cut but look what and the +blue relative to the orange at the end + + align:start position:0% +blue relative to the orange at the end + + + align:start position:0% +blue relative to the orange at the end +of the century has a pretty big impact + + align:start position:0% +of the century has a pretty big impact + + + align:start position:0% +of the century has a pretty big impact +on + + align:start position:0% +on + + + align:start position:0% +on +atmospheric uh uh concentrations but the + + align:start position:0% +atmospheric uh uh concentrations but the + + + align:start position:0% +atmospheric uh uh concentrations but the +temperature still goes up the + + align:start position:0% +temperature still goes up the + + + align:start position:0% +temperature still goes up the +temperature still goes up substantially + + align:start position:0% +temperature still goes up substantially + + + align:start position:0% +temperature still goes up substantially +that's a 2 degree or is that a 3 degree + + align:start position:0% +that's a 2 degree or is that a 3 degree + + + align:start position:0% +that's a 2 degree or is that a 3 degree +increase in temperature temperature 3° C + + align:start position:0% +increase in temperature temperature 3° C + + + align:start position:0% +increase in temperature temperature 3° C +Fahrenheit increase in temperature uh + + align:start position:0% +Fahrenheit increase in temperature uh + + + align:start position:0% +Fahrenheit increase in temperature uh +the orange much bigger but that's a big + + align:start position:0% +the orange much bigger but that's a big + + + align:start position:0% +the orange much bigger but that's a big +change right if you're going from here + + align:start position:0% +change right if you're going from here + + + align:start position:0% +change right if you're going from here +to + + align:start position:0% +to + + + align:start position:0% +to +here China's not getting rich burning + + align:start position:0% +here China's not getting rich burning + + + align:start position:0% +here China's not getting rich burning +coal on that on the blue path we're not + + align:start position:0% +coal on that on the blue path we're not + + + align:start position:0% +coal on that on the blue path we're not +uh increasing our energy at all probably + + align:start position:0% +uh increasing our energy at all probably + + + align:start position:0% +uh increasing our energy at all probably +Europe is cutting back even farther to + + align:start position:0% +Europe is cutting back even farther to + + + align:start position:0% +Europe is cutting back even farther to +get to that blue path that's a big + + align:start position:0% +get to that blue path that's a big + + + align:start position:0% +get to that blue path that's a big +deal that's so if it's the easiest thing + + align:start position:0% +deal that's so if it's the easiest thing + + + align:start position:0% +deal that's so if it's the easiest thing +to do and it's an important thing to do + + align:start position:0% +to do and it's an important thing to do + + + align:start position:0% +to do and it's an important thing to do +it's a big deal so that's one reason why + + align:start position:0% +it's a big deal so that's one reason why + + + align:start position:0% +it's a big deal so that's one reason why +it's hard is we live on fossil fuels so + + align:start position:0% +it's hard is we live on fossil fuels so + + + align:start position:0% +it's hard is we live on fossil fuels so +if you're going to cut the use of fossil + + align:start position:0% +if you're going to cut the use of fossil + + + align:start position:0% +if you're going to cut the use of fossil +fuels emissions from fossil + + align:start position:0% +fuels emissions from fossil + + + align:start position:0% +fuels emissions from fossil +fuels it's emissions from fossil fuels + + align:start position:0% +fuels it's emissions from fossil fuels + + + align:start position:0% +fuels it's emissions from fossil fuels +uh you can do some fuel switching you + + align:start position:0% +uh you can do some fuel switching you + + + align:start position:0% +uh you can do some fuel switching you +can do some efficiency you can do some + + align:start position:0% +can do some efficiency you can do some + + + align:start position:0% +can do some efficiency you can do some +this that and the other but you will + + align:start position:0% +this that and the other but you will + + + align:start position:0% +this that and the other but you will +have to do a + + align:start position:0% +have to do a + + + align:start position:0% +have to do a +lot new technologies will be essential + + align:start position:0% +lot new technologies will be essential + + + align:start position:0% +lot new technologies will be essential +but they may or may not appear in + + align:start position:0% +but they may or may not appear in + + + align:start position:0% +but they may or may not appear in +time okay okay so that's a big deal so + + align:start position:0% +time okay okay so that's a big deal so + + + align:start position:0% +time okay okay so that's a big deal so +we all go to bicycles that's great we + + align:start position:0% +we all go to bicycles that's great we + + + align:start position:0% +we all go to bicycles that's great we +can do that we can emulate the Dutch and + + align:start position:0% +can do that we can emulate the Dutch and + + + align:start position:0% +can do that we can emulate the Dutch and +we can all bicycle to + + align:start position:0% +we can all bicycle to + + + align:start position:0% +we can all bicycle to +work but we're not the + + align:start position:0% + + + + align:start position:0% + +problem any projection of the future + + align:start position:0% +problem any projection of the future + + + align:start position:0% +problem any projection of the future +says the growth in emissions will come + + align:start position:0% +says the growth in emissions will come + + + align:start position:0% +says the growth in emissions will come +from countries that are now poor they + + align:start position:0% +from countries that are now poor they + + + align:start position:0% +from countries that are now poor they +have been growing more rapidly than + + align:start position:0% +have been growing more rapidly than + + + align:start position:0% +have been growing more rapidly than +countries that are now Rich for some + + align:start position:0% +countries that are now Rich for some + + + align:start position:0% +countries that are now Rich for some +time and all projections are they will + + align:start position:0% +time and all projections are they will + + + align:start position:0% +time and all projections are they will +continue to do so so this is from BP's + + align:start position:0% +continue to do so so this is from BP's + + + align:start position:0% +continue to do so so this is from BP's +energy Outlook if you look up to + + align:start position:0% +energy Outlook if you look up to + + + align:start position:0% +energy Outlook if you look up to +2020 1990 to 20110 you'll see oecd + + align:start position:0% +2020 1990 to 20110 you'll see oecd + + + align:start position:0% +2020 1990 to 20110 you'll see oecd +emissions rich country emissions pretty + + align:start position:0% +emissions rich country emissions pretty + + + align:start position:0% +emissions rich country emissions pretty +flat I mean they'd be up a bit but for + + align:start position:0% +flat I mean they'd be up a bit but for + + + align:start position:0% +flat I mean they'd be up a bit but for +the recession but not much but dramatic + + align:start position:0% +the recession but not much but dramatic + + + align:start position:0% +the recession but not much but dramatic +growth in the less rich countries + + align:start position:0% +growth in the less rich countries + + + align:start position:0% +growth in the less rich countries +derotic growth again for the world as a + + align:start position:0% +derotic growth again for the world as a + + + align:start position:0% +derotic growth again for the world as a +whole energy and co2 have grown less + + align:start position:0% +whole energy and co2 have grown less + + + align:start position:0% +whole energy and co2 have grown less +rapidly than GDP that + + align:start position:0% +rapidly than GDP that + + + align:start position:0% +rapidly than GDP that +declining we saw in the US is a general + + align:start position:0% +declining we saw in the US is a general + + + align:start position:0% +declining we saw in the US is a general +phenomenon + + align:start position:0% +phenomenon + + + align:start position:0% +phenomenon +but if you don't you know if you try to + + align:start position:0% +but if you don't you know if you try to + + + align:start position:0% +but if you don't you know if you try to +control Global emissions try to reduce + + align:start position:0% +control Global emissions try to reduce + + + align:start position:0% +control Global emissions try to reduce +Global emissions by reducing oecd + + align:start position:0% +Global emissions by reducing oecd + + + align:start position:0% +Global emissions by reducing oecd +emissions you see if if we go to Zero by + + align:start position:0% +emissions you see if if we go to Zero by + + + align:start position:0% +emissions you see if if we go to Zero by +2030 and and the non + + align:start position:0% +2030 and and the non + + + align:start position:0% +2030 and and the non +oec D proceeds on the track Global + + align:start position:0% +oec D proceeds on the track Global + + + align:start position:0% +oec D proceeds on the track Global +emissions will be up + + align:start position:0% +emissions will be up + + + align:start position:0% +emissions will be up +right just by + + align:start position:0% +right just by + + + align:start position:0% +right just by +I so yeah + + align:start position:0% + + + + align:start position:0% + +Sam policy changes the idea what those + + align:start position:0% +Sam policy changes the idea what those + + + align:start position:0% +Sam policy changes the idea what those +could be + + align:start position:0% +could be + + + align:start position:0% +could be +um you know you read the report and you + + align:start position:0% +um you know you read the report and you + + + align:start position:0% +um you know you read the report and you +say + + align:start position:0% +say + + + align:start position:0% +say +well what are they assuming they're + + align:start position:0% +well what are they assuming they're + + + align:start position:0% +well what are they assuming they're +assuming tightening restrictions in + + align:start position:0% +assuming tightening restrictions in + + + align:start position:0% +assuming tightening restrictions in +Europe they're assuming something in the + + align:start position:0% +Europe they're assuming something in the + + + align:start position:0% +Europe they're assuming something in the +US they're assuming uh continued + + align:start position:0% +US they're assuming uh continued + + + align:start position:0% +US they're assuming uh continued +efficiency increases they're not + + align:start position:0% +efficiency increases they're not + + + align:start position:0% +efficiency increases they're not +assuming the kind of global agreement + + align:start position:0% +assuming the kind of global agreement + + + align:start position:0% +assuming the kind of global agreement +you guys are going to negotiate + + align:start position:0% +you guys are going to negotiate + + + align:start position:0% +you guys are going to negotiate +Wednesday and Friday that's clear + + align:start position:0% +Wednesday and Friday that's clear + + + align:start position:0% +Wednesday and Friday that's clear +they're not assuming sort of a second + + align:start position:0% +they're not assuming sort of a second + + + align:start position:0% +they're not assuming sort of a second +Kyoto Protocol ratified by the whole + + align:start position:0% +Kyoto Protocol ratified by the whole + + + align:start position:0% +Kyoto Protocol ratified by the whole +world uh I think and it's an interesting + + align:start position:0% +world uh I think and it's an interesting + + + align:start position:0% +world uh I think and it's an interesting +assumption to assume that absent + + align:start position:0% +assumption to assume that absent + + + align:start position:0% +assumption to assume that absent +anything going on in these countries + + align:start position:0% +anything going on in these countries + + + align:start position:0% +anything going on in these countries +that these countries will continue I + + align:start position:0% +that these countries will continue I + + + align:start position:0% +that these countries will continue I +mean here they're showing a reduction a + + align:start position:0% +mean here they're showing a reduction a + + + align:start position:0% +mean here they're showing a reduction a +positive reduction in emissions here + + align:start position:0% +positive reduction in emissions here + + + align:start position:0% +positive reduction in emissions here +over that period so that that is and + + align:start position:0% +over that period so that that is and + + + align:start position:0% +over that period so that that is and +there's growth not huge growth but + + align:start position:0% +there's growth not huge growth but + + + align:start position:0% +there's growth not huge growth but +there's growth so they're assuming a + + align:start position:0% +there's growth so they're assuming a + + + align:start position:0% +there's growth so they're assuming a +tightening in the oecd continued + + align:start position:0% +tightening in the oecd continued + + + align:start position:0% +tightening in the oecd continued +efficiency increases + + align:start position:0% +efficiency increases + + + align:start position:0% +efficiency increases +here some I there some discussion of of + + align:start position:0% +here some I there some discussion of of + + + align:start position:0% +here some I there some discussion of of +China becoming a bit a bit less carbon + + align:start position:0% +China becoming a bit a bit less carbon + + + align:start position:0% +China becoming a bit a bit less carbon +intensive but but the main policy + + align:start position:0% +intensive but but the main policy + + + align:start position:0% +intensive but but the main policy +actions here and they do not assume a + + align:start position:0% +actions here and they do not assume a + + + align:start position:0% +actions here and they do not assume a +global + + align:start position:0% +global + + + align:start position:0% +global +agreement um it's a short description I + + align:start position:0% +agreement um it's a short description I + + + align:start position:0% +agreement um it's a short description I +invite you to read it it's about two + + align:start position:0% +invite you to read it it's about two + + + align:start position:0% +invite you to read it it's about two +pages see what see what you think they + + align:start position:0% +pages see what see what you think they + + + align:start position:0% +pages see what see what you think they +assume but that's how I get that's what + + align:start position:0% +assume but that's how I get that's what + + + align:start position:0% +assume but that's how I get that's what +I get out of it you can see there there + + align:start position:0% +I get out of it you can see there there + + + align:start position:0% +I get out of it you can see there there +continuing to assume for the world as a + + align:start position:0% +continuing to assume for the world as a + + + align:start position:0% +continuing to assume for the world as a +whole uh efficiency increases right the + + align:start position:0% +whole uh efficiency increases right the + + + align:start position:0% +whole uh efficiency increases right the +GDP grows much more rapidly than energy + + align:start position:0% +GDP grows much more rapidly than energy + + + align:start position:0% +GDP grows much more rapidly than energy +use and they're continuing to assume for + + align:start position:0% +use and they're continuing to assume for + + + align:start position:0% +use and they're continuing to assume for +the world as a whole decarbonization + + align:start position:0% +the world as a whole decarbonization + + + align:start position:0% +the world as a whole decarbonization +presumably presumably a switch out of + + align:start position:0% +presumably presumably a switch out of + + + align:start position:0% +presumably presumably a switch out of +coal into natural gas and Renewables I'd + + align:start position:0% +coal into natural gas and Renewables I'd + + + align:start position:0% +coal into natural gas and Renewables I'd +have to go back and check but I think + + align:start position:0% +have to go back and check but I think + + + align:start position:0% +have to go back and check but I think +that's part of the + + align:start position:0% +that's part of the + + + align:start position:0% +that's part of the +scenario anything else yeah how big is + + align:start position:0% +scenario anything else yeah how big is + + + align:start position:0% +scenario anything else yeah how big is +the impact of other emissions like + + align:start position:0% +the impact of other emissions like + + + align:start position:0% +the impact of other emissions like +methane I know that it keeps more + + align:start position:0% +methane I know that it keeps more + + + align:start position:0% +methane I know that it keeps more +heat methane uh has + + align:start position:0% +heat methane uh has + + + align:start position:0% +heat methane uh has +a the reason for not focusing on methane + + align:start position:0% +a the reason for not focusing on methane + + + align:start position:0% +a the reason for not focusing on methane +even though it it is a more potent heat + + align:start position:0% +even though it it is a more potent heat + + + align:start position:0% +even though it it is a more potent heat +trapping gas it doesn't stay in the + + align:start position:0% +trapping gas it doesn't stay in the + + + align:start position:0% +trapping gas it doesn't stay in the +atmosphere is long a so it's about 10 + + align:start position:0% +atmosphere is long a so it's about 10 + + + align:start position:0% +atmosphere is long a so it's about 10 +year halflife by ballpark about 10 years + + align:start position:0% +year halflife by ballpark about 10 years + + + align:start position:0% +year halflife by ballpark about 10 years +uh and B it's harder to figure it has + + align:start position:0% +uh and B it's harder to figure it has + + + align:start position:0% +uh and B it's harder to figure it has +many sources so it's got natural gas + + align:start position:0% +many sources so it's got natural gas + + + align:start position:0% +many sources so it's got natural gas +leaks it's got got uh landfill + + align:start position:0% +leaks it's got got uh landfill + + + align:start position:0% +leaks it's got got uh landfill +decomposition it's got things rotting so + + align:start position:0% +decomposition it's got things rotting so + + + align:start position:0% +decomposition it's got things rotting so +it's + + align:start position:0% +it's + + + align:start position:0% +it's +harder to control and in fact in 20 + + align:start position:0% +harder to control and in fact in 20 + + + align:start position:0% +harder to control and in fact in 20 +years 30 + + align:start position:0% +years 30 + + + align:start position:0% +years 30 +years uh less serious yeah please I + + align:start position:0% +years uh less serious yeah please I + + + align:start position:0% +years uh less serious yeah please I +think part of the confusion on methane + + align:start position:0% +think part of the confusion on methane + + + align:start position:0% +think part of the confusion on methane +is that although every molecule of + + align:start position:0% +is that although every molecule of + + + align:start position:0% +is that although every molecule of +methane is more potent than a molecule + + align:start position:0% +methane is more potent than a molecule + + + align:start position:0% +methane is more potent than a molecule +of CO2 there's a lot more CO2 in the + + align:start position:0% +of CO2 there's a lot more CO2 in the + + + align:start position:0% +of CO2 there's a lot more CO2 in the +atmosphere so actually CO2 doing three + + align:start position:0% +atmosphere so actually CO2 doing three + + + align:start position:0% +atmosphere so actually CO2 doing three +times more warming right now than the + + align:start position:0% +times more warming right now than the + + + align:start position:0% +times more warming right now than the +total of all the methane because there's + + align:start position:0% +total of all the methane because there's + + + align:start position:0% +total of all the methane because there's +so much more of it even though each + + align:start position:0% +so much more of it even though each + + + align:start position:0% +so much more of it even though each +methane molecule is a strong guy yeah I + + align:start position:0% +methane molecule is a strong guy yeah I + + + align:start position:0% +methane molecule is a strong guy yeah I +didn't do that yeah I didn't do that I + + align:start position:0% +didn't do that yeah I didn't do that I + + + align:start position:0% +didn't do that yeah I didn't do that I +should have done it I should have done + + align:start position:0% +should have done it I should have done + + + align:start position:0% +should have done it I should have done +it um yeah if you if you break + + align:start position:0% +it um yeah if you if you break + + + align:start position:0% +it um yeah if you if you break +down sources of anthropogenic warming + + align:start position:0% +down sources of anthropogenic warming + + + align:start position:0% +down sources of anthropogenic warming +CO2 + + align:start position:0% +CO2 + + + align:start position:0% +CO2 +dominates when people get to talking + + align:start position:0% +dominates when people get to talking + + + align:start position:0% +dominates when people get to talking +about methane being an effective + + align:start position:0% +about methane being an effective + + + align:start position:0% +about methane being an effective +greenhouse gas it can get very confusing + + align:start position:0% +greenhouse gas it can get very confusing + + + align:start position:0% +greenhouse gas it can get very confusing +yeah yeah so for this we have the CO2 + + align:start position:0% +yeah yeah so for this we have the CO2 + + + align:start position:0% +yeah yeah so for this we have the CO2 +emissions by the the + + align:start position:0% +emissions by the the + + + align:start position:0% +emissions by the the +oesd countries right yep but in term of + + align:start position:0% +oesd countries right yep but in term of + + + align:start position:0% +oesd countries right yep but in term of +population I think the O count we're + + align:start position:0% +population I think the O count we're + + + align:start position:0% +population I think the O count we're +going to come there we're going to break + + align:start position:0% +going to come there we're going to break + + + align:start position:0% +going to come there we're going to break +it down yes you are in terms of per + + align:start position:0% +it down yes you are in terms of per + + + align:start position:0% +it down yes you are in terms of per +capita the oecd countries are much + + align:start position:0% +capita the oecd countries are much + + + align:start position:0% +capita the oecd countries are much +higher but the only point to be made + + align:start position:0% +higher but the only point to be made + + + align:start position:0% +higher but the only point to be made +here is if you want this top graph to + + align:start position:0% +here is if you want this top graph to + + + align:start position:0% +here is if you want this top graph to +come down you're not going to get it all + + align:start position:0% +come down you're not going to get it all + + + align:start position:0% +come down you're not going to get it all +here and you got to do something up + + align:start position:0% +here and you got to do something up + + + align:start position:0% +here and you got to do something up +here somehow somehow um we will come to + + align:start position:0% +here somehow somehow um we will come to + + + align:start position:0% +here somehow somehow um we will come to +questions of fairness in about a half a + + align:start position:0% +questions of fairness in about a half a + + + align:start position:0% +questions of fairness in about a half a +second but uh so that's that's a + + align:start position:0% +second but uh so that's that's a + + + align:start position:0% +second but uh so that's that's a +reason you you're going to have to deal + + align:start position:0% +reason you you're going to have to deal + + + align:start position:0% +reason you you're going to have to deal +with + + align:start position:0% +with + + + align:start position:0% +with +growth and the growth is going to come + + align:start position:0% +growth and the growth is going to come + + + align:start position:0% +growth and the growth is going to come +from many from countries that are now + + align:start position:0% +from many from countries that are now + + + align:start position:0% +from many from countries that are now +poorer than the oecd + + align:start position:0% +poorer than the oecd + + + align:start position:0% +poorer than the oecd +countries the other reason let me just + + align:start position:0% +countries the other reason let me just + + + align:start position:0% +countries the other reason let me just +briefly + + align:start position:0% +briefly + + + align:start position:0% +briefly +do a little economics here as opposed to + + align:start position:0% +do a little economics here as opposed to + + + align:start position:0% +do a little economics here as opposed to +a little a little pseudo + + align:start position:0% +a little a little pseudo + + + align:start position:0% +a little a little pseudo +science + + align:start position:0% +science + + + align:start position:0% +science +suppose you want to reduce + + align:start position:0% +suppose you want to reduce + + + align:start position:0% +suppose you want to reduce +emissions say you want to Total + + align:start position:0% +emissions say you want to Total + + + align:start position:0% +emissions say you want to Total +reduction emissions uh from business as + + align:start position:0% +reduction emissions uh from business as + + + align:start position:0% +reduction emissions uh from business as +usual of capital + + align:start position:0% +usual of capital + + + align:start position:0% +usual of capital +r and you want to do it worldwide and + + align:start position:0% +r and you want to do it worldwide and + + + align:start position:0% +r and you want to do it worldwide and +the cost of getting reductions in + + align:start position:0% +the cost of getting reductions in + + + align:start position:0% +the cost of getting reductions in +country I is given by this cost function + + align:start position:0% +country I is given by this cost function + + + align:start position:0% +country I is given by this cost function +all right so the Zar cares about global + + align:start position:0% +all right so the Zar cares about global + + + align:start position:0% +all right so the Zar cares about global +cost so what the Zar is going to do is + + align:start position:0% +cost so what the Zar is going to do is + + + align:start position:0% +cost so what the Zar is going to do is +is reduce emissions he's going to + + align:start position:0% +is reduce emissions he's going to + + + align:start position:0% +is reduce emissions he's going to +minimize the total cost subject to this + + align:start position:0% +minimize the total cost subject to this + + + align:start position:0% +minimize the total cost subject to this +constraint and if if you recall or just + + align:start position:0% +constraint and if if you recall or just + + + align:start position:0% +constraint and if if you recall or just +use your intuition you're going to have + + align:start position:0% +use your intuition you're going to have + + + align:start position:0% +use your intuition you're going to have +to have the marginal cost the derivative + + align:start position:0% +to have the marginal cost the derivative + + + align:start position:0% +to have the marginal cost the derivative +of this function with respect to its + + align:start position:0% +of this function with respect to its + + + align:start position:0% +of this function with respect to its +argument equal across + + align:start position:0% +argument equal across + + + align:start position:0% +argument equal across +countries if not I can rearrange + + align:start position:0% +countries if not I can rearrange + + + align:start position:0% +countries if not I can rearrange +reductions in a way that'll lower cost + + align:start position:0% +reductions in a way that'll lower cost + + + align:start position:0% +reductions in a way that'll lower cost +I'll do a little more where marginal + + align:start position:0% +I'll do a little more where marginal + + + align:start position:0% +I'll do a little more where marginal +cost is low and a little less where + + align:start position:0% +cost is low and a little less where + + + align:start position:0% +cost is low and a little less where +marginal cost is high get the same + + align:start position:0% +marginal cost is high get the same + + + align:start position:0% +marginal cost is high get the same +reductions lower cost that's always true + + align:start position:0% +reductions lower cost that's always true + + + align:start position:0% +reductions lower cost that's always true +unless the marginal costs are equal well + + align:start position:0% +unless the marginal costs are equal well + + + align:start position:0% +unless the marginal costs are equal well +I I if marginal costs are going to be + + align:start position:0% +I I if marginal costs are going to be + + + align:start position:0% +I I if marginal costs are going to be +equal then unless it's really + + align:start position:0% +equal then unless it's really + + + align:start position:0% +equal then unless it's really +hard to reduce emissions in poor + + align:start position:0% +hard to reduce emissions in poor + + + align:start position:0% +hard to reduce emissions in poor +countries they have to play if we're + + align:start position:0% +countries they have to play if we're + + + align:start position:0% +countries they have to play if we're +going to reduce total cost that's not + + align:start position:0% +going to reduce total cost that's not + + + align:start position:0% +going to reduce total cost that's not +it's not a question of who pays for it + + align:start position:0% +it's not a question of who pays for it + + + align:start position:0% +it's not a question of who pays for it +it's a question of where it + + align:start position:0% +it's a question of where it + + + align:start position:0% +it's a question of where it +happens right doesn't say that that + + align:start position:0% +happens right doesn't say that that + + + align:start position:0% +happens right doesn't say that that +Bangladesh has to pay to reduce + + align:start position:0% +Bangladesh has to pay to reduce + + + align:start position:0% +Bangladesh has to pay to reduce +emissions in Bangladesh it says that + + align:start position:0% +emissions in Bangladesh it says that + + + align:start position:0% +emissions in Bangladesh it says that +emissions in Bangladesh will have to be + + align:start position:0% +emissions in Bangladesh will have to be + + + align:start position:0% +emissions in Bangladesh will have to be +reduced so there's separate questions + + align:start position:0% +reduced so there's separate questions + + + align:start position:0% +reduced so there's separate questions +but it says the poor will need to be + + align:start position:0% +but it says the poor will need to be + + + align:start position:0% +but it says the poor will need to be +involved this + + align:start position:0% +involved this + + + align:start position:0% +involved this +is + + align:start position:0% +is + + + align:start position:0% +is +um if you + + align:start position:0% +um if you + + + align:start position:0% +um if you +recall 1401 if you have a firm producing + + align:start position:0% +recall 1401 if you have a firm producing + + + align:start position:0% +recall 1401 if you have a firm producing +in multiple plants this is exactly the + + align:start position:0% +in multiple plants this is exactly the + + + align:start position:0% +in multiple plants this is exactly the +same exactly the same principle you want + + align:start position:0% +same exactly the same principle you want + + + align:start position:0% +same exactly the same principle you want +to equalize on the + + align:start position:0% +to equalize on the + + + align:start position:0% +to equalize on the +margin that means everybody normally it + + align:start position:0% +margin that means everybody normally it + + + align:start position:0% +margin that means everybody normally it +means everybody has to + + align:start position:0% +means everybody has to + + + align:start position:0% +means everybody has to +play there are two approaches that have + + align:start position:0% +play there are two approaches that have + + + align:start position:0% +play there are two approaches that have +been put on the table for this and we'll + + align:start position:0% +been put on the table for this and we'll + + + align:start position:0% +been put on the table for this and we'll +come back we'll come back to both of + + align:start position:0% +come back we'll come back to both of + + + align:start position:0% +come back we'll come back to both of +them The Parson at all piece on the + + align:start position:0% +them The Parson at all piece on the + + + align:start position:0% +them The Parson at all piece on the +reading list which is optional talks + + align:start position:0% +reading list which is optional talks + + + align:start position:0% +reading list which is optional talks +about talks about one of them you could + + align:start position:0% +about talks about one of them you could + + + align:start position:0% +about talks about one of them you could +say all right how + + align:start position:0% +say all right how + + + align:start position:0% +say all right how +about the Zar + + align:start position:0% + + + + align:start position:0% + +says + + align:start position:0% +says + + + align:start position:0% +says +there's a price of $20 a ton for carbon + + align:start position:0% +there's a price of $20 a ton for carbon + + + align:start position:0% +there's a price of $20 a ton for carbon +emissions from fossil + + align:start position:0% +emissions from fossil + + + align:start position:0% +emissions from fossil +fuels the Zar doesn't like to do central + + align:start position:0% +fuels the Zar doesn't like to do central + + + align:start position:0% +fuels the Zar doesn't like to do central +planning uh he's learned that lesson but + + align:start position:0% +planning uh he's learned that lesson but + + + align:start position:0% +planning uh he's learned that lesson but +the Zar can Tinker with prices so he'll + + align:start position:0% +the Zar can Tinker with prices so he'll + + + align:start position:0% +the Zar can Tinker with prices so he'll +put a price of $20 a ton for + + align:start position:0% +put a price of $20 a ton for + + + align:start position:0% +put a price of $20 a ton for +emissions well that means everybody + + align:start position:0% +emissions well that means everybody + + + align:start position:0% +emissions well that means everybody +who's contemplating emissions is going + + align:start position:0% +who's contemplating emissions is going + + + align:start position:0% +who's contemplating emissions is going +to cut back until the cost of cutting + + align:start position:0% +to cut back until the cost of cutting + + + align:start position:0% +to cut back until the cost of cutting +back Rises to + + align:start position:0% +back Rises to + + + align:start position:0% +back Rises to +$20 and I'll get this marginal cost + + align:start position:0% +$20 and I'll get this marginal cost + + + align:start position:0% +$20 and I'll get this marginal cost +equality that + + align:start position:0% +equality that + + + align:start position:0% +equality that +way right so I just price the thing we + + align:start position:0% +way right so I just price the thing we + + + align:start position:0% +way right so I just price the thing we +talked about this earlier this is + + align:start position:0% +talked about this earlier this is + + + align:start position:0% +talked about this earlier this is +pricing the harm so I price the harm + + align:start position:0% +pricing the harm so I price the harm + + + align:start position:0% +pricing the harm so I price the harm +people cut back on the + + align:start position:0% +people cut back on the + + + align:start position:0% +people cut back on the +harm um it's a tax it'll show up as a + + align:start position:0% +harm um it's a tax it'll show up as a + + + align:start position:0% +harm um it's a tax it'll show up as a +tax on probably show up as a tax on + + align:start position:0% +tax on probably show up as a tax on + + + align:start position:0% +tax on probably show up as a tax on +fuel right tax much higher on coal than + + align:start position:0% +fuel right tax much higher on coal than + + + align:start position:0% +fuel right tax much higher on coal than +on natural gas but that's one way to do + + align:start position:0% +on natural gas but that's one way to do + + + align:start position:0% +on natural gas but that's one way to do +it and and and the Zar the Zar can do + + align:start position:0% +it and and and the Zar the Zar can do + + + align:start position:0% +it and and and the Zar the Zar can do +that the other way to do + + align:start position:0% +that the other way to do + + + align:start position:0% +that the other way to do +it that makes sense right that's easy we + + align:start position:0% +it that makes sense right that's easy we + + + align:start position:0% +it that makes sense right that's easy we +just price the + + align:start position:0% + + + + align:start position:0% + +thing the other way to do it is a little + + align:start position:0% +thing the other way to do it is a little + + + align:start position:0% +thing the other way to do it is a little +more convoluted but only a little more + + align:start position:0% +more convoluted but only a little more + + + align:start position:0% +more convoluted but only a little more +and we'll return to the equivalence + + align:start position:0% +and we'll return to the equivalence + + + align:start position:0% +and we'll return to the equivalence +later on + + align:start position:0% +later on + + + align:start position:0% +later on +is the our prints up statistic uh prints + + align:start position:0% +is the our prints up statistic uh prints + + + align:start position:0% +is the our prints up statistic uh prints +up certificates drops them from + + align:start position:0% +up certificates drops them from + + + align:start position:0% +up certificates drops them from +helicopters and + + align:start position:0% +helicopters and + + + align:start position:0% +helicopters and +says to emit a ton of CO2 you have to + + align:start position:0% +says to emit a ton of CO2 you have to + + + align:start position:0% +says to emit a ton of CO2 you have to +give me a + + align:start position:0% +give me a + + + align:start position:0% +give me a +certificate limited number number of + + align:start position:0% +certificate limited number number of + + + align:start position:0% +certificate limited number number of +certificates equal to the total amount + + align:start position:0% +certificates equal to the total amount + + + align:start position:0% +certificates equal to the total amount +of CO2 the Zar wants to + + align:start position:0% +of CO2 the Zar wants to + + + align:start position:0% +of CO2 the Zar wants to +permit you get a + + align:start position:0% +permit you get a + + + align:start position:0% +permit you get a +market right I go around looking for + + align:start position:0% +market right I go around looking for + + + align:start position:0% +market right I go around looking for +certificates I'm willing to pay 20 bucks + + align:start position:0% +certificates I'm willing to pay 20 bucks + + + align:start position:0% +certificates I'm willing to pay 20 bucks +for it I'm willing to pay some price the + + align:start position:0% +for it I'm willing to pay some price the + + + align:start position:0% +for it I'm willing to pay some price the +market will determine what price in this + + align:start position:0% +market will determine what price in this + + + align:start position:0% +market will determine what price in this +case if I fix a price the market will + + align:start position:0% +case if I fix a price the market will + + + align:start position:0% +case if I fix a price the market will +determine the + + align:start position:0% +determine the + + + align:start position:0% +determine the +quantity if I fix a quantity the market + + align:start position:0% +quantity if I fix a quantity the market + + + align:start position:0% +quantity if I fix a quantity the market +will determine the price but I can go + + align:start position:0% +will determine the price but I can go + + + align:start position:0% +will determine the price but I can go +either + + align:start position:0% +either + + + align:start position:0% +either +way and if thear knows all doesn't + + align:start position:0% +way and if thear knows all doesn't + + + align:start position:0% +way and if thear knows all doesn't +matter which way he + + align:start position:0% +matter which way he + + + align:start position:0% +matter which way he +goes we'll talk a little later I think + + align:start position:0% +goes we'll talk a little later I think + + + align:start position:0% +goes we'll talk a little later I think +about about when and where and how it + + align:start position:0% +about about when and where and how it + + + align:start position:0% +about about when and where and how it +might matter + + align:start position:0% +might matter + + + align:start position:0% +might matter +but that's what thear might that's what + + align:start position:0% +but that's what thear might that's what + + + align:start position:0% +but that's what thear might that's what +thear might want to do right do those + + align:start position:0% +thear might want to do right do those + + + align:start position:0% +thear might want to do right do those +make sort of top of the head sense as a + + align:start position:0% +make sort of top of the head sense as a + + + align:start position:0% +make sort of top of the head sense as a +way to do it without without having to + + align:start position:0% +way to do it without without having to + + + align:start position:0% +way to do it without without having to +do central + + align:start position:0% +do central + + + align:start position:0% +do central +planning for all the nations of the + + align:start position:0% +planning for all the nations of the + + + align:start position:0% +planning for all the nations of the +world but if you say it's $30 a ton or + + align:start position:0% +world but if you say it's $30 a ton or + + + align:start position:0% +world but if you say it's $30 a ton or +$40 a ton on for + + align:start position:0% +$40 a ton on for + + + align:start position:0% +$40 a ton on for +everybody and poor countries have to pay + + align:start position:0% +everybody and poor countries have to pay + + + align:start position:0% +everybody and poor countries have to pay +it how do they do that how do they do + + align:start position:0% +it how do they do that how do they do + + + align:start position:0% +it how do they do that how do they do +that so you know that they're going to + + align:start position:0% +that so you know that they're going to + + + align:start position:0% +that so you know that they're going to +have to do some + + align:start position:0% +have to do some + + + align:start position:0% +have to do some +reduction because if you think about + + align:start position:0% + + + + align:start position:0% + +it they're building buildings facilities + + align:start position:0% +it they're building buildings facilities + + + align:start position:0% +it they're building buildings facilities +Etc it's a lot cheaper to insulate a new + + align:start position:0% +Etc it's a lot cheaper to insulate a new + + + align:start position:0% +Etc it's a lot cheaper to insulate a new +house when it's being built to go back + + align:start position:0% +house when it's being built to go back + + + align:start position:0% +house when it's being built to go back +and and retrofit an old house it's a lot + + align:start position:0% +and and retrofit an old house it's a lot + + + align:start position:0% +and and retrofit an old house it's a lot +cheaper to make a new power plant + + align:start position:0% +cheaper to make a new power plant + + + align:start position:0% +cheaper to make a new power plant +efficient than to repower an old Power + + align:start position:0% +efficient than to repower an old Power + + + align:start position:0% +efficient than to repower an old Power +Plant so if the new if the poorer + + align:start position:0% +Plant so if the new if the poorer + + + align:start position:0% +Plant so if the new if the poorer +countries of the world are growing more + + align:start position:0% +countries of the world are growing more + + + align:start position:0% +countries of the world are growing more +rapidly they have a lot more relatively + + align:start position:0% +rapidly they have a lot more relatively + + + align:start position:0% +rapidly they have a lot more relatively +inexpensive investment + + align:start position:0% +inexpensive investment + + + align:start position:0% +inexpensive investment +opportunities they also may not have + + align:start position:0% +opportunities they also may not have + + + align:start position:0% +opportunities they also may not have +built Los Angeles yet so they're in a + + align:start position:0% +built Los Angeles yet so they're in a + + + align:start position:0% +built Los Angeles yet so they're in a +position to decide more easily on a + + align:start position:0% +position to decide more easily on a + + + align:start position:0% +position to decide more easily on a +different Urban + + align:start position:0% +different Urban + + + align:start position:0% +different Urban +structure less less spread out less + + align:start position:0% +structure less less spread out less + + + align:start position:0% +structure less less spread out less +reliant on cars so there are a set of + + align:start position:0% +reliant on cars so there are a set of + + + align:start position:0% +reliant on cars so there are a set of +choices that are being + + align:start position:0% +choices that are being + + + align:start position:0% +choices that are being +made there also if you look at retrofit + + align:start position:0% +made there also if you look at retrofit + + + align:start position:0% +made there also if you look at retrofit +options there's a lot of energy use + + align:start position:0% +options there's a lot of energy use + + + align:start position:0% +options there's a lot of energy use +now that is polluting as well as + + align:start position:0% +now that is polluting as well as + + + align:start position:0% +now that is polluting as well as +inefficient so modernizing some of the + + align:start position:0% +inefficient so modernizing some of the + + + align:start position:0% +inefficient so modernizing some of the +plants now uh will create a double + + align:start position:0% +plants now uh will create a double + + + align:start position:0% +plants now uh will create a double +benefit I you can do something besides + + align:start position:0% +benefit I you can do something besides + + + align:start position:0% +benefit I you can do something besides +little kerosene generators for instance + + align:start position:0% +little kerosene generators for instance + + + align:start position:0% +little kerosene generators for instance +for electricity in a lot of places you + + align:start position:0% +for electricity in a lot of places you + + + align:start position:0% +for electricity in a lot of places you +will not only save energy but you clean + + align:start position:0% +will not only save energy but you clean + + + align:start position:0% +will not only save energy but you clean +the air so there's a benefit to be had + + align:start position:0% +the air so there's a benefit to be had + + + align:start position:0% +the air so there's a benefit to be had +in + + align:start position:0% +in + + + align:start position:0% +in +bringing these countries + + align:start position:0% +bringing these countries + + + align:start position:0% +bringing these countries +closer uh to the + + align:start position:0% +closer uh to the + + + align:start position:0% +closer uh to the +frontier with what they already + + align:start position:0% +frontier with what they already + + + align:start position:0% +frontier with what they already +have + + align:start position:0% +have + + + align:start position:0% +have +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so this is a hard problem for the + + align:start position:0% +so this is a hard problem for the + + + align:start position:0% +so this is a hard problem for the +zar + + align:start position:0% +zar + + + align:start position:0% +zar +the Zar has to figure out how she's + + align:start position:0% +the Zar has to figure out how she's + + + align:start position:0% +the Zar has to figure out how she's +going to or the Zar Arena how she's + + align:start position:0% +going to or the Zar Arena how she's + + + align:start position:0% +going to or the Zar Arena how she's +going to deal with the distant future + + align:start position:0% +going to deal with the distant future + + + align:start position:0% +going to deal with the distant future +and great great + + align:start position:0% +and great great + + + align:start position:0% +and great great +grandchildren + + align:start position:0% +grandchildren + + + align:start position:0% +grandchildren +how to get to deal with uncertainty + + align:start position:0% +how to get to deal with uncertainty + + + align:start position:0% +how to get to deal with uncertainty +today and to learn to deal with it + + align:start position:0% +today and to learn to deal with it + + + align:start position:0% +today and to learn to deal with it +tomorrow as Learning + + align:start position:0% +tomorrow as Learning + + + align:start position:0% +tomorrow as Learning +Happens thear is going to have to figure + + align:start position:0% +Happens thear is going to have to figure + + + align:start position:0% +Happens thear is going to have to figure +out what if anything could be done about + + align:start position:0% +out what if anything could be done about + + + align:start position:0% +out what if anything could be done about +Technologies how to get people en a to + + align:start position:0% +Technologies how to get people en a to + + + align:start position:0% +Technologies how to get people en a to +adapt + + align:start position:0% +adapt + + + align:start position:0% +adapt +if the Zar focuses on fossil + + align:start position:0% +if the Zar focuses on fossil + + + align:start position:0% +if the Zar focuses on fossil +fuel the Zar has to make big changes and + + align:start position:0% +fuel the Zar has to make big changes and + + + align:start position:0% +fuel the Zar has to make big changes and +the Zar has to involve the + + align:start position:0% +the Zar has to involve the + + + align:start position:0% +the Zar has to involve the +poor the Zar has to involve the poor it + + align:start position:0% +poor the Zar has to involve the poor it + + + align:start position:0% +poor the Zar has to involve the poor it +can't be done by Rich countries if rich + + align:start position:0% +can't be done by Rich countries if rich + + + align:start position:0% +can't be done by Rich countries if rich +countries alone try to do it you know if + + align:start position:0% +countries alone try to do it you know if + + + align:start position:0% +countries alone try to do it you know if +you go back to something like this you + + align:start position:0% +you go back to something like this you + + + align:start position:0% +you go back to something like this you +want to slow growth in you want to + + align:start position:0% +want to slow growth in you want to + + + align:start position:0% +want to slow growth in you want to +eliminate growth in emissions by only + + align:start position:0% +eliminate growth in emissions by only + + + align:start position:0% +eliminate growth in emissions by only +the rich countries they'd have to go to + + align:start position:0% +the rich countries they'd have to go to + + + align:start position:0% +the rich countries they'd have to go to +zero to have a big impact it ain't going + + align:start position:0% +zero to have a big impact it ain't going + + + align:start position:0% +zero to have a big impact it ain't going +to happen so the poor need to be + + align:start position:0% +to happen so the poor need to be + + + align:start position:0% +to happen so the poor need to be +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +involved and the first question that + + align:start position:0% +involved and the first question that + + + align:start position:0% +involved and the first question that +comes + + align:start position:0% +comes + + + align:start position:0% +comes +up already came up is that + + align:start position:0% + + + + align:start position:0% + +fair this is a missions per + + align:start position:0% +fair this is a missions per + + + align:start position:0% +fair this is a missions per +capita this is uh Annex 2 North America + + align:start position:0% +capita this is uh Annex 2 North America + + + align:start position:0% +capita this is uh Annex 2 North America +is US and Canada this is Australia New + + align:start position:0% +is US and Canada this is Australia New + + + align:start position:0% +is US and Canada this is Australia New +Zealand + + align:start position:0% +Zealand + + + align:start position:0% +Zealand +Japan uh EIT or economies in transition + + align:start position:0% +Japan uh EIT or economies in transition + + + align:start position:0% +Japan uh EIT or economies in transition +that's uh um Russia and Eastern Europe + + align:start position:0% +that's uh um Russia and Eastern Europe + + + align:start position:0% +that's uh um Russia and Eastern Europe +there's the Middle East Annex two Europe + + align:start position:0% +there's the Middle East Annex two Europe + + + align:start position:0% +there's the Middle East Annex two Europe +or Rich European countries China other + + align:start position:0% +or Rich European countries China other + + + align:start position:0% +or Rich European countries China other +countries Latin America the rest of Asia + + align:start position:0% + + + + align:start position:0% + +Africa is it fair to involve + + align:start position:0% +Africa is it fair to involve + + + align:start position:0% +Africa is it fair to involve +them my golly that's you're going to go + + align:start position:0% +them my golly that's you're going to go + + + align:start position:0% +them my golly that's you're going to go +to you're going to go to Cambodia you + + align:start position:0% +to you're going to go to Cambodia you + + + align:start position:0% +to you're going to go to Cambodia you +remember I I put up the Cambodia energy + + align:start position:0% +remember I I put up the Cambodia energy + + + align:start position:0% +remember I I put up the Cambodia energy +diagram some while ago Cambodia Imports + + align:start position:0% +diagram some while ago Cambodia Imports + + + align:start position:0% +diagram some while ago Cambodia Imports +some oil and burns a lot of + + align:start position:0% +some oil and burns a lot of + + + align:start position:0% +some oil and burns a lot of +wood that's the Energy + + align:start position:0% + + + + align:start position:0% + +System you know and they mostly ride + + align:start position:0% +System you know and they mostly ride + + + align:start position:0% +System you know and they mostly ride +motorbikes and you can't get them much + + align:start position:0% +motorbikes and you can't get them much + + + align:start position:0% +motorbikes and you can't get them much +smaller um than the ones they have so to + + align:start position:0% +smaller um than the ones they have so to + + + align:start position:0% +smaller um than the ones they have so to +ha this is an enormous + + align:start position:0% +ha this is an enormous + + + align:start position:0% +ha this is an enormous +disparity right North America is running + + align:start position:0% +disparity right North America is running + + + align:start position:0% +disparity right North America is running +I don't know 16 metric tons per capita + + align:start position:0% +I don't know 16 metric tons per capita + + + align:start position:0% +I don't know 16 metric tons per capita +Africa is running less than one big + + align:start position:0% +Africa is running less than one big + + + align:start position:0% +Africa is running less than one big +disparity huge disparity very different + + align:start position:0% +disparity huge disparity very different + + + align:start position:0% +disparity huge disparity very different +very different system so if you're going + + align:start position:0% +very different system so if you're going + + + align:start position:0% +very different system so if you're going +to + + align:start position:0% +to + + + align:start position:0% +to +change you're going to look people in + + align:start position:0% +change you're going to look people in + + + align:start position:0% +change you're going to look people in +the face and those of you who want to be + + align:start position:0% +the face and those of you who want to be + + + align:start position:0% +the face and those of you who want to be +developing countries or developed + + align:start position:0% +developing countries or developed + + + align:start position:0% +developing countries or developed +countries on Wednesday and Friday you're + + align:start position:0% +countries on Wednesday and Friday you're + + + align:start position:0% +countries on Wednesday and Friday you're +going to look your poor brethren in the + + align:start position:0% +going to look your poor brethren in the + + + align:start position:0% +going to look your poor brethren in the +face and + + align:start position:0% +face and + + + align:start position:0% +face and +say you Latin America rest of Asia + + align:start position:0% +say you Latin America rest of Asia + + + align:start position:0% +say you Latin America rest of Asia +Africa boy you got to take steps we'll + + align:start position:0% +Africa boy you got to take steps we'll + + + align:start position:0% +Africa boy you got to take steps we'll +do what we + + align:start position:0% +do what we + + + align:start position:0% +do what we +can but you've got to take steps see we + + align:start position:0% +can but you've got to take steps see we + + + align:start position:0% +can but you've got to take steps see we +we have path dependence up here we're + + align:start position:0% +we have path dependence up here we're + + + align:start position:0% +we have path dependence up here we're +we're kind of stuck on a path and you + + align:start position:0% +we're kind of stuck on a path and you + + + align:start position:0% +we're kind of stuck on a path and you +know what are you going going to do + + align:start position:0% +know what are you going going to do + + + align:start position:0% +know what are you going going to do +um so fairness is also in you know one + + align:start position:0% +um so fairness is also in you know one + + + align:start position:0% +um so fairness is also in you know one +response might be yeah well let's look + + align:start position:0% +response might be yeah well let's look + + + align:start position:0% +response might be yeah well let's look +at let's look not per capita but you + + align:start position:0% +at let's look not per capita but you + + + align:start position:0% +at let's look not per capita but you +know you're you're low cause you're + + align:start position:0% +know you're you're low cause you're + + + align:start position:0% +know you're you're low cause you're +really really poor and we're really + + align:start position:0% +really really poor and we're really + + + align:start position:0% +really really poor and we're really +really sad about it but per dollar of + + align:start position:0% +really sad about it but per dollar of + + + align:start position:0% +really sad about it but per dollar of +GDP the differences are less + + align:start position:0% +GDP the differences are less + + + align:start position:0% +GDP the differences are less +Stark the winners now are the Middle + + align:start position:0% +Stark the winners now are the Middle + + + align:start position:0% +Stark the winners now are the Middle +East Soviet Union in Eastern Europe + + align:start position:0% +East Soviet Union in Eastern Europe + + + align:start position:0% +East Soviet Union in Eastern Europe +because those were really manufacturing + + align:start position:0% +because those were really manufacturing + + + align:start position:0% +because those were really manufacturing +intensive Technologies they ran on cheap + + align:start position:0% +intensive Technologies they ran on cheap + + + align:start position:0% +intensive Technologies they ran on cheap +Russian + + align:start position:0% +Russian + + + align:start position:0% +Russian +oil which was made available at low cost + + align:start position:0% +oil which was made available at low cost + + + align:start position:0% +oil which was made available at low cost +and Russian natural gas they still have + + align:start position:0% +and Russian natural gas they still have + + + align:start position:0% +and Russian natural gas they still have +an enormous amount of inefficient + + align:start position:0% +an enormous amount of inefficient + + + align:start position:0% +an enormous amount of inefficient +Capital stock + + align:start position:0% +Capital stock + + + align:start position:0% +Capital stock +running um and China which has a + + align:start position:0% +running um and China which has a + + + align:start position:0% +running um and China which has a +manufacturing intensive economy and uses + + align:start position:0% +manufacturing intensive economy and uses + + + align:start position:0% +manufacturing intensive economy and uses +a lot of + + align:start position:0% +a lot of + + + align:start position:0% +a lot of +coal so you know per unit of GDP + + align:start position:0% +coal so you know per unit of GDP + + + align:start position:0% +coal so you know per unit of GDP +Africa's right in there with everybody + + align:start position:0% +Africa's right in there with everybody + + + align:start position:0% +Africa's right in there with everybody +else + + align:start position:0% +else + + + align:start position:0% +else +they just happen to have not much GDP + + align:start position:0% +they just happen to have not much GDP + + + align:start position:0% +they just happen to have not much GDP +per capita so you say well you know per + + align:start position:0% +per capita so you say well you know per + + + align:start position:0% +per capita so you say well you know per +dollar of GDP we can make Cuts you can + + align:start position:0% +dollar of GDP we can make Cuts you can + + + align:start position:0% +dollar of GDP we can make Cuts you can +make + + align:start position:0% +make + + + align:start position:0% +make +cuts and one response might be yeah but + + align:start position:0% +cuts and one response might be yeah but + + + align:start position:0% +cuts and one response might be yeah but +we'd like our GDP to grow thank you very + + align:start position:0% +we'd like our GDP to grow thank you very + + + align:start position:0% +we'd like our GDP to grow thank you very +much + + align:start position:0% +much + + + align:start position:0% +much +so this is another nice example this is + + align:start position:0% +so this is another nice example this is + + + align:start position:0% +so this is another nice example this is +if you do the cumulative you do what's + + align:start position:0% +if you do the cumulative you do what's + + + align:start position:0% +if you do the cumulative you do what's +in the + + align:start position:0% +in the + + + align:start position:0% +in the +air um which was the point professor + + align:start position:0% +air um which was the point professor + + + align:start position:0% +air um which was the point professor +Solomon was making if you do what's in + + align:start position:0% +Solomon was making if you do what's in + + + align:start position:0% +Solomon was making if you do what's in +the air this is just CO2 but it's co it + + align:start position:0% +the air this is just CO2 but it's co it + + + align:start position:0% +the air this is just CO2 but it's co it +shows cumulatively what's in the air + + align:start position:0% +shows cumulatively what's in the air + + + align:start position:0% +shows cumulatively what's in the air +now based on a model of the carbon cycle + + align:start position:0% +now based on a model of the carbon cycle + + + align:start position:0% +now based on a model of the carbon cycle +what's in the air now and where it came + + align:start position:0% +what's in the air now and where it came + + + align:start position:0% +what's in the air now and where it came +from Blue is the rich countries this + + align:start position:0% +from Blue is the rich countries this + + + align:start position:0% +from Blue is the rich countries this +this is kind of middle- inome developing + + align:start position:0% +this is kind of middle- inome developing + + + align:start position:0% +this is kind of middle- inome developing +countries and that's the very + + align:start position:0% +countries and that's the very + + + align:start position:0% +countries and that's the very +poor so in terms of who caused the + + align:start position:0% +poor so in terms of who caused the + + + align:start position:0% +poor so in terms of who caused the +problem it's not who who put the stuff + + align:start position:0% +problem it's not who who put the stuff + + + align:start position:0% +problem it's not who who put the stuff +in the air it's not China who's putting + + align:start position:0% +in the air it's not China who's putting + + + align:start position:0% +in the air it's not China who's putting +it in the air and who's growing yeah but + + align:start position:0% +it in the air and who's growing yeah but + + + align:start position:0% +it in the air and who's growing yeah but +who put it + + align:start position:0% +who put it + + + align:start position:0% +who put it +there it's + + align:start position:0% +there it's + + + align:start position:0% +there it's +us + + align:start position:0% + + + + align:start position:0% + +okay A little bit of of sort of how the + + align:start position:0% +okay A little bit of of sort of how the + + + align:start position:0% +okay A little bit of of sort of how the +international conversation on all of + + align:start position:0% +international conversation on all of + + + align:start position:0% +international conversation on all of +this has gone just by way of background + + align:start position:0% +this has gone just by way of background + + + align:start position:0% +this has gone just by way of background +and then we'll see what questions you + + align:start position:0% +and then we'll see what questions you + + + align:start position:0% +and then we'll see what questions you +have because I've gone through this much + + align:start position:0% +have because I've gone through this much + + + align:start position:0% +have because I've gone through this much +too rapidly um as I mentioned the + + align:start position:0% +too rapidly um as I mentioned the + + + align:start position:0% +too rapidly um as I mentioned the +framework convention on climate change + + align:start position:0% +framework convention on climate change + + + align:start position:0% +framework convention on climate change +was was um drafted in 1992 ratified by + + align:start position:0% +was was um drafted in 1992 ratified by + + + align:start position:0% +was was um drafted in 1992 ratified by +everybody there have been 17 conferences + + align:start position:0% +everybody there have been 17 conferences + + + align:start position:0% +everybody there have been 17 conferences +of the parties referred to as + + align:start position:0% +of the parties referred to as + + + align:start position:0% +of the parties referred to as +cops um large Gatherings of diplomats + + align:start position:0% +cops um large Gatherings of diplomats + + + align:start position:0% +cops um large Gatherings of diplomats +non-governmental organizations + + align:start position:0% +non-governmental organizations + + + align:start position:0% +non-governmental organizations +demonstrators hangers on um cocktail + + align:start position:0% +demonstrators hangers on um cocktail + + + align:start position:0% +demonstrators hangers on um cocktail +parties receptions + + align:start position:0% +parties receptions + + + align:start position:0% +parties receptions +there have been 17 of + + align:start position:0% +there have been 17 of + + + align:start position:0% +there have been 17 of +them you will be the + + align:start position:0% +them you will be the + + + align:start position:0% +them you will be the +18th um the third produced the Kyoto + + align:start position:0% +18th um the third produced the Kyoto + + + align:start position:0% +18th um the third produced the Kyoto +Protocol the framework convention + + align:start position:0% +Protocol the framework convention + + + align:start position:0% +Protocol the framework convention +divided the world into Annex one + + align:start position:0% +divided the world into Annex one + + + align:start position:0% +divided the world into Annex one +countries and everybody else Annex 2 + + align:start position:0% +countries and everybody else Annex 2 + + + align:start position:0% +countries and everybody else Annex 2 +which was on some of those earlier + + align:start position:0% +which was on some of those earlier + + + align:start position:0% +which was on some of those earlier +graphs is a a subset of anex one it's + + align:start position:0% +graphs is a a subset of anex one it's + + + align:start position:0% +graphs is a a subset of anex one it's +the Richer Annex one + + align:start position:0% +the Richer Annex one + + + align:start position:0% +the Richer Annex one +countries the Kyoto Protocol + + align:start position:0% +countries the Kyoto Protocol + + + align:start position:0% +countries the Kyoto Protocol +called for Annex one countries + + align:start position:0% +called for Annex one countries + + + align:start position:0% +called for Annex one countries +only and by the way it's not all rich + + align:start position:0% +only and by the way it's not all rich + + + align:start position:0% +only and by the way it's not all rich +countries South Korea is not Annex one + + align:start position:0% +countries South Korea is not Annex one + + + align:start position:0% +countries South Korea is not Annex one +um Singapore is not Annex one uh Saudi + + align:start position:0% +um Singapore is not Annex one uh Saudi + + + align:start position:0% +um Singapore is not Annex one uh Saudi +Arabia is not Annex one and so forth so + + align:start position:0% +Arabia is not Annex one and so forth so + + + align:start position:0% +Arabia is not Annex one and so forth so +it's a industrialized + + align:start position:0% +it's a industrialized + + + align:start position:0% +it's a industrialized +countries o oecd roughly + + align:start position:0% +countries o oecd roughly + + + align:start position:0% +countries o oecd roughly +oecd Annex one + + align:start position:0% +oecd Annex one + + + align:start position:0% +oecd Annex one +countries uh were to make reductions + + align:start position:0% +countries uh were to make reductions + + + align:start position:0% +countries uh were to make reductions +there were negotiated reductions + + align:start position:0% +there were negotiated reductions + + + align:start position:0% +there were negotiated reductions +the rest of the world which I just said + + align:start position:0% +the rest of the world which I just said + + + align:start position:0% +the rest of the world which I just said +Has to participate if something's going + + align:start position:0% +Has to participate if something's going + + + align:start position:0% +Has to participate if something's going +to happen refus to even promise making + + align:start position:0% +to happen refus to even promise making + + + align:start position:0% +to happen refus to even promise making +promises in the + + align:start position:0% +promises in the + + + align:start position:0% +promises in the +future so there wasn't even a commitment + + align:start position:0% +future so there wasn't even a commitment + + + align:start position:0% +future so there wasn't even a commitment +to make a commitment they would not + + align:start position:0% +to make a commitment they would not + + + align:start position:0% +to make a commitment they would not +commit to + + align:start position:0% +commit to + + + align:start position:0% +commit to +commit uh and if you think about that + + align:start position:0% +commit uh and if you think about that + + + align:start position:0% +commit uh and if you think about that +that's really + + align:start position:0% +that's really + + + align:start position:0% +that's really +resisting um we'll be happy to come to + + align:start position:0% +resisting um we'll be happy to come to + + + align:start position:0% +resisting um we'll be happy to come to +these meetings but we do not now promise + + align:start position:0% +these meetings but we do not now promise + + + align:start position:0% +these meetings but we do not now promise +ever to commit to do anything unless of + + align:start position:0% +ever to commit to do anything unless of + + + align:start position:0% +ever to commit to do anything unless of +course it's paid for so the Kyoto + + align:start position:0% +course it's paid for so the Kyoto + + + align:start position:0% +course it's paid for so the Kyoto +Protocol called for anx1 countries to + + align:start position:0% +Protocol called for anx1 countries to + + + align:start position:0% +Protocol called for anx1 countries to +make + + align:start position:0% +make + + + align:start position:0% +make +reductions it was + + align:start position:0% +reductions it was + + + align:start position:0% +reductions it was +ratified by the members of the East + + align:start position:0% +ratified by the members of the East + + + align:start position:0% +ratified by the members of the East +European Union + + align:start position:0% +European Union + + + align:start position:0% +European Union +Japan Australia Canada uh lots of other + + align:start position:0% +Japan Australia Canada uh lots of other + + + align:start position:0% +Japan Australia Canada uh lots of other +folks uh we did + + align:start position:0% +folks uh we did + + + align:start position:0% +folks uh we did +not the history of that is roughly that + + align:start position:0% +not the history of that is roughly that + + + align:start position:0% +not the history of that is roughly that +uh President Clinton in the runup to + + align:start position:0% +uh President Clinton in the runup to + + + align:start position:0% +uh President Clinton in the runup to +those + + align:start position:0% +those + + + align:start position:0% +those +negotiations had a lot of there was a + + align:start position:0% +negotiations had a lot of there was a + + + align:start position:0% +negotiations had a lot of there was a +lot of noise in the air about how this + + align:start position:0% +lot of noise in the air about how this + + + align:start position:0% +lot of noise in the air about how this +will be free it'll be a great benefit to + + align:start position:0% +will be free it'll be a great benefit to + + + align:start position:0% +will be free it'll be a great benefit to +the US economy this will be fabulous we + + align:start position:0% +the US economy this will be fabulous we + + + align:start position:0% +the US economy this will be fabulous we +can reduce emissions it'll be no cost + + align:start position:0% +can reduce emissions it'll be no cost + + + align:start position:0% +can reduce emissions it'll be no cost +every Economist not working for the + + align:start position:0% +every Economist not working for the + + + align:start position:0% +every Economist not working for the +administration stood up and said well + + align:start position:0% +administration stood up and said well + + + align:start position:0% +administration stood up and said well +it's not going to cost that much money + + align:start position:0% +it's not going to cost that much money + + + align:start position:0% +it's not going to cost that much money +but it will + + align:start position:0% +but it will + + + align:start position:0% +but it will +cost Congress passed a resolution 95 to + + align:start position:0% +cost Congress passed a resolution 95 to + + + align:start position:0% +cost Congress passed a resolution 95 to +nothing saying we won't ratify anything + + align:start position:0% +nothing saying we won't ratify anything + + + align:start position:0% +nothing saying we won't ratify anything +that basically slightly different + + align:start position:0% +that basically slightly different + + + align:start position:0% +that basically slightly different +language that doesn't require the + + align:start position:0% +language that doesn't require the + + + align:start position:0% +language that doesn't require the +Chinese to do something now 95 to + + align:start position:0% +Chinese to do something now 95 to + + + align:start position:0% +Chinese to do something now 95 to +nothing + + align:start position:0% +nothing + + + align:start position:0% +nothing +so Al Gore went to Kyoto the US said + + align:start position:0% +so Al Gore went to Kyoto the US said + + + align:start position:0% +so Al Gore went to Kyoto the US said +this is fabulous we made an agreement + + align:start position:0% +this is fabulous we made an agreement + + + align:start position:0% +this is fabulous we made an agreement +the treaty was not sent to the senate + + align:start position:0% +the treaty was not sent to the senate + + + align:start position:0% +the treaty was not sent to the senate +for + + align:start position:0% +for + + + align:start position:0% +for +ratification uh and President George W + + align:start position:0% +ratification uh and President George W + + + align:start position:0% +ratification uh and President George W +bush uh formally declared the horse dead + + align:start position:0% +bush uh formally declared the horse dead + + + align:start position:0% +bush uh formally declared the horse dead +in 2001 when he said we're not going to + + align:start position:0% +in 2001 when he said we're not going to + + + align:start position:0% +in 2001 when he said we're not going to +play so the EU has established and again + + align:start position:0% +play so the EU has established and again + + + align:start position:0% +play so the EU has established and again +you can read The Parson at all article + + align:start position:0% +you can read The Parson at all article + + + align:start position:0% +you can read The Parson at all article +if you're interested in it established + + align:start position:0% +if you're interested in it established + + + align:start position:0% +if you're interested in it established +an emissions trading scheme they did + + align:start position:0% +an emissions trading scheme they did + + + align:start position:0% +an emissions trading scheme they did +these certificates Dro from the air that + + align:start position:0% +these certificates Dro from the air that + + + align:start position:0% +these certificates Dro from the air that +let you emit carbon dioxide I mean it's + + align:start position:0% +let you emit carbon dioxide I mean it's + + + align:start position:0% +let you emit carbon dioxide I mean it's +not a perfect system you'll see some + + align:start position:0% +not a perfect system you'll see some + + + align:start position:0% +not a perfect system you'll see some +glitches um but it may work and they may + + align:start position:0% +glitches um but it may work and they may + + + align:start position:0% +glitches um but it may work and they may +actually meet their + + align:start position:0% +actually meet their + + + align:start position:0% +actually meet their +commitments it doesn't appear anybody + + align:start position:0% +commitments it doesn't appear anybody + + + align:start position:0% +commitments it doesn't appear anybody +else will even those that ratified the + + align:start position:0% +else will even those that ratified the + + + align:start position:0% +else will even those that ratified the +treaty Australia is walking away I think + + align:start position:0% +treaty Australia is walking away I think + + + align:start position:0% +treaty Australia is walking away I think +Canada has walked away Japan Japan May + + align:start position:0% +Canada has walked away Japan Japan May + + + align:start position:0% +Canada has walked away Japan Japan May +because of of the incredible disaster + + align:start position:0% +because of of the incredible disaster + + + align:start position:0% +because of of the incredible disaster +they've gone through but would not have + + align:start position:0% +they've gone through but would not have + + + align:start position:0% +they've gone through but would not have +absent it um and may not since they now + + align:start position:0% +absent it um and may not since they now + + + align:start position:0% +absent it um and may not since they now +say that they will replace the nuclear + + align:start position:0% +say that they will replace the nuclear + + + align:start position:0% +say that they will replace the nuclear +plants with coal so we'll see but at any + + align:start position:0% +plants with coal so we'll see but at any + + + align:start position:0% +plants with coal so we'll see but at any +rate nothing will + + align:start position:0% +rate nothing will + + + align:start position:0% +rate nothing will +happen + + align:start position:0% +happen + + + align:start position:0% +happen +the subsequent agreements H there was + + align:start position:0% +the subsequent agreements H there was + + + align:start position:0% +the subsequent agreements H there was +Copenhagen there was a lot of fuss + + align:start position:0% +Copenhagen there was a lot of fuss + + + align:start position:0% +Copenhagen there was a lot of fuss +around Copenhagen you'll see the runup + + align:start position:0% +around Copenhagen you'll see the runup + + + align:start position:0% +around Copenhagen you'll see the runup +discussed in The Economist reading you + + align:start position:0% +discussed in The Economist reading you + + + align:start position:0% +discussed in The Economist reading you +will see the most recent Doha discussed + + align:start position:0% +will see the most recent Doha discussed + + + align:start position:0% +will see the most recent Doha discussed +in the second very short Economist + + align:start position:0% +in the second very short Economist + + + align:start position:0% +in the second very short Economist +reading happened in + + align:start position:0% +reading happened in + + + align:start position:0% +reading happened in +December um there are no Global there's + + align:start position:0% +December um there are no Global there's + + + align:start position:0% +December um there are no Global there's +no Global agreement in + + align:start position:0% +no Global agreement in + + + align:start position:0% +no Global agreement in +place what happened in Doha and I uh + + align:start position:0% +place what happened in Doha and I uh + + + align:start position:0% +place what happened in Doha and I uh +it's on it's on my slides for for + + align:start position:0% +it's on it's on my slides for for + + + align:start position:0% +it's on it's on my slides for for +Wednesday but I'll tell you now what + + align:start position:0% +Wednesday but I'll tell you now what + + + align:start position:0% +Wednesday but I'll tell you now what +happened in + + align:start position:0% +happened in + + + align:start position:0% +happened in +Doha was basically the Europeans agreed + + align:start position:0% +Doha was basically the Europeans agreed + + + align:start position:0% +Doha was basically the Europeans agreed +to + + align:start position:0% +to + + + align:start position:0% +to +continue um there was a promise of money + + align:start position:0% +continue um there was a promise of money + + + align:start position:0% +continue um there was a promise of money +to go from the rich countries to the + + align:start position:0% +to go from the rich countries to the + + + align:start position:0% +to go from the rich countries to the +poor countries a much smaller promise + + align:start position:0% +poor countries a much smaller promise + + + align:start position:0% +poor countries a much smaller promise +than you will consider Wednesday and + + align:start position:0% +than you will consider Wednesday and + + + align:start position:0% +than you will consider Wednesday and +Friday but there was a promise we'll see + + align:start position:0% +Friday but there was a promise we'll see + + + align:start position:0% +Friday but there was a promise we'll see +if it's + + align:start position:0% +if it's + + + align:start position:0% +if it's +kept um + + align:start position:0% +kept um + + + align:start position:0% +kept um +and the developing World promised to + + align:start position:0% +and the developing World promised to + + + align:start position:0% +and the developing World promised to +consider making + + align:start position:0% +consider making + + + align:start position:0% +consider making +promises that is to say the refusal to + + align:start position:0% +promises that is to say the refusal to + + + align:start position:0% +promises that is to say the refusal to +commit ever to commit is off the table + + align:start position:0% +commit ever to commit is off the table + + + align:start position:0% +commit ever to commit is off the table +they now say they will consider in + + align:start position:0% +they now say they will consider in + + + align:start position:0% +they now say they will consider in +subsequent negotiations beginning in + + align:start position:0% +subsequent negotiations beginning in + + + align:start position:0% +subsequent negotiations beginning in +2015 participating in a global + + align:start position:0% +2015 participating in a global + + + align:start position:0% +2015 participating in a global +regime of some sort not fully spelled + + align:start position:0% +regime of some sort not fully spelled + + + align:start position:0% +regime of some sort not fully spelled +out so the poor countries as I say need + + align:start position:0% +out so the poor countries as I say need + + + align:start position:0% +out so the poor countries as I say need +to + + align:start position:0% +to + + + align:start position:0% +to +participate have managed to be excluded + + align:start position:0% +participate have managed to be excluded + + + align:start position:0% +participate have managed to be excluded +so + + align:start position:0% + + + + align:start position:0% + +far the task you will face on Wednesday + + align:start position:0% +far the task you will face on Wednesday + + + align:start position:0% +far the task you will face on Wednesday +and Friday is to is to and I hope do it + + align:start position:0% +and Friday is to is to and I hope do it + + + align:start position:0% +and Friday is to is to and I hope do it +with a straight + + align:start position:0% +with a straight + + + align:start position:0% +with a straight +face uh is to make proposals that have + + align:start position:0% +face uh is to make proposals that have + + + align:start position:0% +face uh is to make proposals that have +some hope of being accepted when you go + + align:start position:0% +some hope of being accepted when you go + + + align:start position:0% +some hope of being accepted when you go +back to your + + align:start position:0% +back to your + + + align:start position:0% +back to your +capitals uh of emissions reductions that + + align:start position:0% +capitals uh of emissions reductions that + + + align:start position:0% +capitals uh of emissions reductions that +will get the job done globally okay I've + + align:start position:0% +will get the job done globally okay I've + + + align:start position:0% +will get the job done globally okay I've +covered a lot uh and I'm going to pause + + align:start position:0% +covered a lot uh and I'm going to pause + + + align:start position:0% +covered a lot uh and I'm going to pause +here I hate to quit this early but let + + align:start position:0% +here I hate to quit this early but let + + + align:start position:0% +here I hate to quit this early but let +me see if you have questions or + + align:start position:0% +me see if you have questions or + + + align:start position:0% +me see if you have questions or +comments how do we do + + align:start position:0% + + + + align:start position:0% + +this have you all read the brief + + align:start position:0% +this have you all read the brief + + + align:start position:0% +this have you all read the brief +briefing materials no they're they're up + + align:start position:0% +briefing materials no they're they're up + + + align:start position:0% +briefing materials no they're they're up +for Wednesday I guess + + align:start position:0% + + + + align:start position:0% + +yeah two degrees Celsius which is what + + align:start position:0% +yeah two degrees Celsius which is what + + + align:start position:0% +yeah two degrees Celsius which is what +we're working with because that's how + + align:start position:0% +we're working with because that's how + + + align:start position:0% +we're working with because that's how +the uh uh exercise was set is really + + align:start position:0% +the uh uh exercise was set is really + + + align:start position:0% +the uh uh exercise was set is really +ambitious at this + + align:start position:0% +ambitious at this + + + align:start position:0% +ambitious at this +stage I mean it is the co it is the goal + + align:start position:0% +stage I mean it is the co it is the goal + + + align:start position:0% +stage I mean it is the co it is the goal +that was adopted in Copenhagen + + align:start position:0% +that was adopted in Copenhagen + + + align:start position:0% +that was adopted in Copenhagen +um it's a very ambitious goal at this + + align:start position:0% +um it's a very ambitious goal at this + + + align:start position:0% +um it's a very ambitious goal at this +stage it might not have been so + + align:start position:0% +stage it might not have been so + + + align:start position:0% +stage it might not have been so +ambitious 20 years ago but now you know + + align:start position:0% +ambitious 20 years ago but now you know + + + align:start position:0% +ambitious 20 years ago but now you know +more stuff in the air stuff going to + + align:start position:0% +more stuff in the air stuff going to + + + align:start position:0% +more stuff in the air stuff going to +stay a long time steeper reductions + + align:start position:0% +stay a long time steeper reductions + + + align:start position:0% +stay a long time steeper reductions +called for yeah I mean who knows what + + align:start position:0% +called for yeah I mean who knows what + + + align:start position:0% +called for yeah I mean who knows what +it's going to take but it's not going to + + align:start position:0% +it's going to take but it's not going to + + + align:start position:0% +it's going to take but it's not going to +be a walk in the park it's going to be + + align:start position:0% +be a walk in the park it's going to be + + + align:start position:0% +be a walk in the park it's going to be +serious + + align:start position:0% + + + + align:start position:0% + +money it is it is but as they say in + + align:start position:0% +money it is it is but as they say in + + + align:start position:0% +money it is it is but as they say in +Washington you've got only a hundred of + + align:start position:0% +Washington you've got only a hundred of + + + align:start position:0% +Washington you've got only a hundred of +those percents to play + + align:start position:0% +those percents to play + + + align:start position:0% +those percents to play +with so less than 1% sounds + + align:start position:0% +with so less than 1% sounds + + + align:start position:0% +with so less than 1% sounds +small until you start saying what does + + align:start position:0% +small until you start saying what does + + + align:start position:0% +small until you start saying what does +that mean we don't do 1% of the + + align:start position:0% +that mean we don't do 1% of the + + + align:start position:0% +that mean we don't do 1% of the +household budget easy but 1% of moving + + align:start position:0% +household budget easy but 1% of moving + + + align:start position:0% +household budget easy but 1% of moving +1% of world GDP from purpose a to + + align:start position:0% +1% of world GDP from purpose a to + + + align:start position:0% +1% of world GDP from purpose a to +purpose B requires governments to do + + align:start position:0% +purpose B requires governments to do + + + align:start position:0% +purpose B requires governments to do +serious things deciding to cut back 1% + + align:start position:0% +serious things deciding to cut back 1% + + + align:start position:0% +serious things deciding to cut back 1% +yourself yeah you can do that it's + + align:start position:0% +yourself yeah you can do that it's + + + align:start position:0% +yourself yeah you can do that it's +nothing but deciding that us is going to + + align:start position:0% +nothing but deciding that us is going to + + + align:start position:0% +nothing but deciding that us is going to +increase spending on something by 1% a + + align:start position:0% +increase spending on something by 1% a + + + align:start position:0% +increase spending on something by 1% a +that's a big percent of government + + align:start position:0% +that's a big percent of government + + + align:start position:0% +that's a big percent of government +bigger percentage of government + + align:start position:0% +bigger percentage of government + + + align:start position:0% +bigger percentage of government +activity and B you're going to have to + + align:start position:0% +activity and B you're going to have to + + + align:start position:0% +activity and B you're going to have to +tax spend torque regulate do significant + + align:start position:0% +tax spend torque regulate do significant + + + align:start position:0% +tax spend torque regulate do significant +things so yeah it's only 1% of GDP and + + align:start position:0% +things so yeah it's only 1% of GDP and + + + align:start position:0% +things so yeah it's only 1% of GDP and +all the models say that's sort of the + + align:start position:0% +all the models say that's sort of the + + + align:start position:0% +all the models say that's sort of the +right order of magnitude for the kinds + + align:start position:0% +right order of magnitude for the kinds + + + align:start position:0% +right order of magnitude for the kinds +of things you'll need to do one maybe + + align:start position:0% +of things you'll need to do one maybe + + + align:start position:0% +of things you'll need to do one maybe +two + + align:start position:0% +two + + + align:start position:0% +two +but it's that that sounds easier than it + + align:start position:0% +but it's that that sounds easier than it + + + align:start position:0% +but it's that that sounds easier than it +is let me just say that another yeah + + align:start position:0% +is let me just say that another yeah + + + align:start position:0% +is let me just say that another yeah +David you talking about the Kyoto + + align:start position:0% +David you talking about the Kyoto + + + align:start position:0% +David you talking about the Kyoto +Protocol and how basically the EU is the + + align:start position:0% +Protocol and how basically the EU is the + + + align:start position:0% +Protocol and how basically the EU is the +only one who even has a chance of + + align:start position:0% +only one who even has a chance of + + + align:start position:0% +only one who even has a chance of +meeting what they promised what's been + + align:start position:0% +meeting what they promised what's been + + + align:start position:0% +meeting what they promised what's been +proposed to like kind of make sure that + + align:start position:0% +proposed to like kind of make sure that + + + align:start position:0% +proposed to like kind of make sure that +people actually meet what they said so + + align:start position:0% +people actually meet what they said so + + + align:start position:0% +people actually meet what they said so +that say I'm the EU and I spent all this + + align:start position:0% +that say I'm the EU and I spent all this + + + align:start position:0% +that say I'm the EU and I spent all this +money trying to control our CO2 + + align:start position:0% +money trying to control our CO2 + + + align:start position:0% +money trying to control our CO2 +emissions we did our part and no one + + align:start position:0% +emissions we did our part and no one + + + align:start position:0% +emissions we did our part and no one +else did and it's really not going to + + align:start position:0% +else did and it's really not going to + + + align:start position:0% +else did and it's really not going to +make a difference well there's all this + + align:start position:0% +make a difference well there's all this + + + align:start position:0% +make a difference well there's all this +money and no one else did there's no + + align:start position:0% +money and no one else did there's no + + + align:start position:0% +money and no one else did there's no +enforcement mechanism um in in the + + align:start position:0% +enforcement mechanism um in in the + + + align:start position:0% +enforcement mechanism um in in the +protocol I don't know that the framework + + align:start position:0% +protocol I don't know that the framework + + + align:start position:0% +protocol I don't know that the framework +convention even allows for the + + align:start position:0% +convention even allows for the + + + align:start position:0% +convention even allows for the +possibility of an enforcement mechanism + + align:start position:0% +possibility of an enforcement mechanism + + + align:start position:0% +possibility of an enforcement mechanism +I'd have to go back and look + + align:start position:0% +I'd have to go back and look + + + align:start position:0% +I'd have to go back and look +um for simple International agreements + + align:start position:0% +um for simple International agreements + + + align:start position:0% +um for simple International agreements +it hasn't mattered much the Montreal + + align:start position:0% +it hasn't mattered much the Montreal + + + align:start position:0% +it hasn't mattered much the Montreal +protocol to phase out ozone depleting + + align:start position:0% +protocol to phase out ozone depleting + + + align:start position:0% +protocol to phase out ozone depleting +substances widely + + align:start position:0% +substances widely + + + align:start position:0% +substances widely +ratified not perfect there's some + + align:start position:0% +ratified not perfect there's some + + + align:start position:0% +ratified not perfect there's some +illegal manufacturing here and there + + align:start position:0% +illegal manufacturing here and there + + + align:start position:0% +illegal manufacturing here and there +but basically it's tiny so most + + align:start position:0% +but basically it's tiny so most + + + align:start position:0% +but basically it's tiny so most +governments can afford to just do it + + align:start position:0% +governments can afford to just do it + + + align:start position:0% +governments can afford to just do it +most countries can afford to do it it's + + align:start position:0% +most countries can afford to do it it's + + + align:start position:0% +most countries can afford to do it it's +a rich countries use those chemicals + + align:start position:0% +a rich countries use those chemicals + + + align:start position:0% +a rich countries use those chemicals +more than poor countries Rich chemicals + + align:start position:0% +more than poor countries Rich chemicals + + + align:start position:0% +more than poor countries Rich chemicals +can afford substit rich countries can + + align:start position:0% +can afford substit rich countries can + + + align:start position:0% +can afford substit rich countries can +afford substitutes not perfect but cheap + + align:start position:0% +afford substitutes not perfect but cheap + + + align:start position:0% +afford substitutes not perfect but cheap +this not so cheap and so no enforcement + + align:start position:0% +this not so cheap and so no enforcement + + + align:start position:0% +this not so cheap and so no enforcement +mechanism there either as far as I know + + align:start position:0% +mechanism there either as far as I know + + + align:start position:0% +mechanism there either as far as I know +I don't think there was in any case it + + align:start position:0% +I don't think there was in any case it + + + align:start position:0% +I don't think there was in any case it +wasn't was never seriously + + align:start position:0% +wasn't was never seriously + + + align:start position:0% +wasn't was never seriously +deployed here + + align:start position:0% +deployed here + + + align:start position:0% +deployed here +what would you do I mean the the + + align:start position:0% +what would you do I mean the the + + + align:start position:0% +what would you do I mean the the +Europeans were ready to go everybody was + + align:start position:0% +Europeans were ready to go everybody was + + + align:start position:0% +Europeans were ready to go everybody was +very excited Al Gore flew to Kyoto it + + align:start position:0% +very excited Al Gore flew to Kyoto it + + + align:start position:0% +very excited Al Gore flew to Kyoto it +was it was High Times and to say the US + + align:start position:0% +was it was High Times and to say the US + + + align:start position:0% +was it was High Times and to say the US +has always talked about monitoring no + + align:start position:0% +has always talked about monitoring no + + + align:start position:0% +has always talked about monitoring no +matter who the president's been we + + align:start position:0% +matter who the president's been we + + + align:start position:0% +matter who the president's been we +always talk about monitoring so in in + + align:start position:0% +always talk about monitoring so in in + + + align:start position:0% +always talk about monitoring so in in +these kinds of discussions nobody + + align:start position:0% +these kinds of discussions nobody + + + align:start position:0% +these kinds of discussions nobody +listens to as much now but we always say + + align:start position:0% +listens to as much now but we always say + + + align:start position:0% +listens to as much now but we always say +gee you ought to actually know if + + align:start position:0% +gee you ought to actually know if + + + align:start position:0% +gee you ought to actually know if +somebody's + + align:start position:0% +somebody's + + + align:start position:0% +somebody's +obeying the obeying the + + align:start position:0% +obeying the obeying the + + + align:start position:0% +obeying the obeying the +agreement um that's resisted by a lot of + + align:start position:0% +agreement um that's resisted by a lot of + + + align:start position:0% +agreement um that's resisted by a lot of +countries um so no and you can now + + align:start position:0% +countries um so no and you can now + + + align:start position:0% +countries um so no and you can now +imagine the beginnings of a European + + align:start position:0% +imagine the beginnings of a European + + + align:start position:0% +imagine the beginnings of a European +reaction wait a minute we're doing all + + align:start position:0% +reaction wait a minute we're doing all + + + align:start position:0% +reaction wait a minute we're doing all +this and what are all these other people + + align:start position:0% +this and what are all these other people + + + align:start position:0% +this and what are all these other people +doing they're smiling at us they're + + align:start position:0% +doing they're smiling at us they're + + + align:start position:0% +doing they're smiling at us they're +Al it it raises the cost of our heavy + + align:start position:0% +Al it it raises the cost of our heavy + + + align:start position:0% +Al it it raises the cost of our heavy +industry our energy intensive industry + + align:start position:0% +industry our energy intensive industry + + + align:start position:0% +industry our energy intensive industry +and wait a minute why are we doing this + + align:start position:0% +and wait a minute why are we doing this + + + align:start position:0% +and wait a minute why are we doing this +again because it's not going to have any + + align:start position:0% +again because it's not going to have any + + + align:start position:0% +again because it's not going to have any +effect right I mean Europe is a + + align:start position:0% +effect right I mean Europe is a + + + align:start position:0% +effect right I mean Europe is a +relatively relative to those big charts + + align:start position:0% +relatively relative to those big charts + + + align:start position:0% +relatively relative to those big charts +the kind of reductions that Europe's + + align:start position:0% +the kind of reductions that Europe's + + + align:start position:0% +the kind of reductions that Europe's +making are hard to + + align:start position:0% +making are hard to + + + align:start position:0% +making are hard to +see on the on the aggregate if I go back + + align:start position:0% + + + + align:start position:0% + +to I go that's the one if I go back to + + align:start position:0% +to I go that's the one if I go back to + + + align:start position:0% +to I go that's the one if I go back to +this one you know Europe might be the + + align:start position:0% +this one you know Europe might be the + + + align:start position:0% +this one you know Europe might be the +width of this + + align:start position:0% +width of this + + + align:start position:0% +width of this +down + + align:start position:0% +down + + + align:start position:0% +down +at some cost so you could imagine the + + align:start position:0% +at some cost so you could imagine the + + + align:start position:0% +at some cost so you could imagine the +European public being less and less + + align:start position:0% +European public being less and less + + + align:start position:0% +European public being less and less +excited just as they've begun to phase + + align:start position:0% +excited just as they've begun to phase + + + align:start position:0% +excited just as they've begun to phase +down uh subsidies for renewable + + align:start position:0% +down uh subsidies for renewable + + + align:start position:0% +down uh subsidies for renewable +energy so yeah it's there's that's part + + align:start position:0% +energy so yeah it's there's that's part + + + align:start position:0% +energy so yeah it's there's that's part +of the problem the Zar can enforce we do + + align:start position:0% +of the problem the Zar can enforce we do + + + align:start position:0% +of the problem the Zar can enforce we do +not have a zar we do not have a zar so + + align:start position:0% +not have a zar we do not have a zar so + + + align:start position:0% +not have a zar we do not have a zar so +when the senate pass resolution saying + + align:start position:0% +when the senate pass resolution saying + + + align:start position:0% +when the senate pass resolution saying +they won't approve anything that doesn't + + align:start position:0% +they won't approve anything that doesn't + + + align:start position:0% +they won't approve anything that doesn't +Force China to also have emissions or + + align:start position:0% +Force China to also have emissions or + + + align:start position:0% +Force China to also have emissions or +emissions reductions didn't say force it + + align:start position:0% +emissions reductions didn't say force it + + + align:start position:0% +emissions reductions didn't say force it +that you can't use Force because none of + + align:start position:0% +that you can't use Force because none of + + + align:start position:0% +that you can't use Force because none of +these + + align:start position:0% +these + + + align:start position:0% +these +agreements that unless it it requires + + align:start position:0% +agreements that unless it it requires + + + align:start position:0% +agreements that unless it it requires +which is to say that China signs on to + + align:start position:0% +which is to say that China signs on to + + + align:start position:0% +which is to say that China signs on to +something that says it will do X yeah + + align:start position:0% +something that says it will do X yeah + + + align:start position:0% +something that says it will do X yeah +but it doesn't specify that they have to + + align:start position:0% +but it doesn't specify that they have to + + + align:start position:0% +but it doesn't specify that they have to +actually be + + align:start position:0% +actually be + + + align:start position:0% +actually be +monitored oh I can't imagine I can't and + + align:start position:0% +monitored oh I can't imagine I can't and + + + align:start position:0% +monitored oh I can't imagine I can't and +you know this country's got a long a + + align:start position:0% +you know this country's got a long a + + + align:start position:0% +you know this country's got a long a +long history of strategic arms reduction + + align:start position:0% +long history of strategic arms reduction + + + align:start position:0% +long history of strategic arms reduction +do you remember well you wouldn't + + align:start position:0% +do you remember well you wouldn't + + + align:start position:0% +do you remember well you wouldn't +remember but you may have heard people + + align:start position:0% +remember but you may have heard people + + + align:start position:0% +remember but you may have heard people +say trust but verify we've always had + + align:start position:0% +say trust but verify we've always had + + + align:start position:0% +say trust but verify we've always had +that view internationally that we want + + align:start position:0% +that view internationally that we want + + + align:start position:0% +that view internationally that we want +to make sure if we're going to obey + + align:start position:0% +to make sure if we're going to obey + + + align:start position:0% +to make sure if we're going to obey +we're going to make sure other people do + + align:start position:0% +we're going to make sure other people do + + + align:start position:0% +we're going to make sure other people do +too at least monitor you may not be able + + align:start position:0% +too at least monitor you may not be able + + + align:start position:0% +too at least monitor you may not be able +to enforce so I can't see us signing + + align:start position:0% +to enforce so I can't see us signing + + + align:start position:0% +to enforce so I can't see us signing +something ratifying something that + + align:start position:0% +something ratifying something that + + + align:start position:0% +something ratifying something that +doesn't have at least monitoring + + align:start position:0% +doesn't have at least monitoring + + + align:start position:0% +doesn't have at least monitoring +Provisions + + align:start position:0% + + + + align:start position:0% + +enforcement look at look at attempts to + + align:start position:0% +enforcement look at look at attempts to + + + align:start position:0% +enforcement look at look at attempts to +take action against Syria the world + + align:start position:0% +take action against Syria the world + + + align:start position:0% +take action against Syria the world +Community doesn't lightly enforce stuff + + align:start position:0% +Community doesn't lightly enforce stuff + + + align:start position:0% +Community doesn't lightly enforce stuff +but every so often Syria Iran something + + align:start position:0% +but every so often Syria Iran something + + + align:start position:0% +but every so often Syria Iran something +gets done but it doesn't get done easily + + align:start position:0% +gets done but it doesn't get done easily + + + align:start position:0% +gets done but it doesn't get done easily +doesn't get done automatically it's a + + align:start position:0% +doesn't get done automatically it's a + + + align:start position:0% +doesn't get done automatically it's a +big political deal David how is this not + + align:start position:0% +big political deal David how is this not + + + align:start position:0% +big political deal David how is this not +led to Stronger partnership laws in that + + align:start position:0% +led to Stronger partnership laws in that + + + align:start position:0% +led to Stronger partnership laws in that +you know I see it as a place where a + + align:start position:0% +you know I see it as a place where a + + + align:start position:0% +you know I see it as a place where a +more developed nation that has you know + + align:start position:0% +more developed nation that has you know + + + align:start position:0% +more developed nation that has you know +high technology inss like MIT could come + + align:start position:0% +high technology inss like MIT could come + + + align:start position:0% +high technology inss like MIT could come +in and talk to a place like Africa and + + align:start position:0% +in and talk to a place like Africa and + + + align:start position:0% +in and talk to a place like Africa and +there's already know a fair amount of + + align:start position:0% +there's already know a fair amount of + + + align:start position:0% +there's already know a fair amount of +infrastructure Investments that's made + + align:start position:0% +infrastructure Investments that's made + + + align:start position:0% +infrastructure Investments that's made +and you know a lot of it can be in the + + align:start position:0% +and you know a lot of it can be in the + + + align:start position:0% +and you know a lot of it can be in the +terms of low interest loans or or you + + align:start position:0% +terms of low interest loans or or you + + + align:start position:0% +terms of low interest loans or or you +provide experts and um help build up the + + align:start position:0% +provide experts and um help build up the + + + align:start position:0% +provide experts and um help build up the +infrastructure because your your cost is + + align:start position:0% +infrastructure because your your cost is + + + align:start position:0% +infrastructure because your your cost is +lower and you're developing something + + align:start position:0% +lower and you're developing something + + + align:start position:0% +lower and you're developing something +new you know you're fostering local here + + align:start position:0% +new you know you're fostering local here + + + align:start position:0% +new you know you're fostering local here +in the states by making that part of + + align:start position:0% +in the states by making that part of + + + align:start position:0% +in the states by making that part of +your avilable Global value but you're + + align:start position:0% +your avilable Global value but you're + + + align:start position:0% +your avilable Global value but you're +also helping internation how does that + + align:start position:0% +also helping internation how does that + + + align:start position:0% +also helping internation how does that +not happen well it it it happens to some + + align:start position:0% +not happen well it it it happens to some + + + align:start position:0% +not happen well it it it happens to some +extent there's a + + align:start position:0% +extent there's a + + + align:start position:0% +extent there's a +problem of of measurement right the + + align:start position:0% +problem of of measurement right the + + + align:start position:0% +problem of of measurement right the +European + + align:start position:0% +European + + + align:start position:0% +European +system the Kyoto the Kyoto Protocol + + align:start position:0% +system the Kyoto the Kyoto Protocol + + + align:start position:0% +system the Kyoto the Kyoto Protocol +provides + + align:start position:0% +provides + + + align:start position:0% +provides +for + + align:start position:0% +for + + + align:start position:0% +for +called Joint + + align:start position:0% +called Joint + + + align:start position:0% +called Joint +implementation well I forget the exact + + align:start position:0% +implementation well I forget the exact + + + align:start position:0% +implementation well I forget the exact +language the clean development mechanism + + align:start position:0% +language the clean development mechanism + + + align:start position:0% +language the clean development mechanism +CDM you can if you're a European + + align:start position:0% +CDM you can if you're a European + + + align:start position:0% +CDM you can if you're a European +company you can meet some of your + + align:start position:0% +company you can meet some of your + + + align:start position:0% +company you can meet some of your +obligations by in by reducing emissions + + align:start position:0% +obligations by in by reducing emissions + + + align:start position:0% +obligations by in by reducing emissions +in a poor country so you can go to + + align:start position:0% +in a poor country so you can go to + + + align:start position:0% +in a poor country so you can go to +China + + align:start position:0% +China + + + align:start position:0% +China +and do a deal bring in new technology do + + align:start position:0% +and do a deal bring in new technology do + + + align:start position:0% +and do a deal bring in new technology do +something that will reduce emissions + + align:start position:0% +something that will reduce emissions + + + align:start position:0% +something that will reduce emissions +and that will give you credit and that's + + align:start position:0% +and that will give you credit and that's + + + align:start position:0% +and that will give you credit and that's +exactly that kind of thinking can we + + align:start position:0% +exactly that kind of thinking can we + + + align:start position:0% +exactly that kind of thinking can we +even though China isn't + + align:start position:0% +even though China isn't + + + align:start position:0% +even though China isn't +participating it's still cheaper to do + + align:start position:0% +participating it's still cheaper to do + + + align:start position:0% +participating it's still cheaper to do +reductions there so let's find a way to + + align:start position:0% +reductions there so let's find a way to + + + align:start position:0% +reductions there so let's find a way to +give countries in Europe credit for + + align:start position:0% +give countries in Europe credit for + + + align:start position:0% +give countries in Europe credit for +reductions in + + align:start position:0% +reductions in + + + align:start position:0% +reductions in +China there are a couple of + + align:start position:0% + + + + align:start position:0% + +problems well it all boils down to one + + align:start position:0% +problems well it all boils down to one + + + align:start position:0% +problems well it all boils down to one +problem really which is how do you + + align:start position:0% +problem really which is how do you + + + align:start position:0% +problem really which is how do you +measure it because it's you you you're + + align:start position:0% +measure it because it's you you you're + + + align:start position:0% +measure it because it's you you you're +reducing over what would have been so + + align:start position:0% +reducing over what would have been so + + + align:start position:0% +reducing over what would have been so +you modernize a + + align:start position:0% +you modernize a + + + align:start position:0% +you modernize a +factory so would that factory have been + + align:start position:0% +factory so would that factory have been + + + align:start position:0% +factory so would that factory have been +running forever with old technology or + + align:start position:0% +running forever with old technology or + + + align:start position:0% +running forever with old technology or +would it have been torn down or would it + + align:start position:0% +would it have been torn down or would it + + + align:start position:0% +would it have been torn down or would it +have been modernized anyway so either + + align:start position:0% +have been modernized anyway so either + + + align:start position:0% +have been modernized anyway so either +your real your real light on how you do + + align:start position:0% +your real your real light on how you do + + + align:start position:0% +your real your real light on how you do +this and you you don't impose real tough + + align:start position:0% +this and you you don't impose real tough + + + align:start position:0% +this and you you don't impose real tough +restrictions and then you're not getting + + align:start position:0% +restrictions and then you're not getting + + + align:start position:0% +restrictions and then you're not getting +real reductions or you you make it + + align:start position:0% +real reductions or you you make it + + + align:start position:0% +real reductions or you you make it +really hard to document in which case + + align:start position:0% +really hard to document in which case + + + align:start position:0% +really hard to document in which case +you kill the market so it's it happens + + align:start position:0% +you kill the market so it's it happens + + + align:start position:0% +you kill the market so it's it happens +and it happens to some extent the + + align:start position:0% +and it happens to some extent the + + + align:start position:0% +and it happens to some extent the +Europeans have gotten a little tired of + + align:start position:0% +Europeans have gotten a little tired of + + + align:start position:0% +Europeans have gotten a little tired of +it as I recall thinking that it's been a + + align:start position:0% +it as I recall thinking that it's been a + + + align:start position:0% +it as I recall thinking that it's been a +little too easy but + + align:start position:0% +little too easy but + + + align:start position:0% +little too easy but +um one of the features of the Waxman + + align:start position:0% +um one of the features of the Waxman + + + align:start position:0% +um one of the features of the Waxman +Mary bill in the + + align:start position:0% +Mary bill in the + + + align:start position:0% +Mary bill in the +US which was the KA trade bill that was + + align:start position:0% +US which was the KA trade bill that was + + + align:start position:0% +US which was the KA trade bill that was +was killed it allowed for + + align:start position:0% +was killed it allowed for + + + align:start position:0% +was killed it allowed for +that for it did it covered only fossil + + align:start position:0% +that for it did it covered only fossil + + + align:start position:0% +that for it did it covered only fossil +fuels but it it allowed companies to get + + align:start position:0% +fuels but it it allowed companies to get + + + align:start position:0% +fuels but it it allowed companies to get +credit for things done in + + align:start position:0% +credit for things done in + + + align:start position:0% +credit for things done in +agriculture so you could change land + + align:start position:0% +agriculture so you could change land + + + align:start position:0% +agriculture so you could change land +use + + align:start position:0% +use + + + align:start position:0% +use +and it it was it was a giveaway to + + align:start position:0% +and it it was it was a giveaway to + + + align:start position:0% +and it it was it was a giveaway to +agriculture basically because the + + align:start position:0% +agriculture basically because the + + + align:start position:0% +agriculture basically because the +standards were going to be pretty easy + + align:start position:0% +standards were going to be pretty easy + + + align:start position:0% +standards were going to be pretty easy +but it was that same notion that that I + + align:start position:0% +but it was that same notion that that I + + + align:start position:0% +but it was that same notion that that I +want to reach out Beyond places that I + + align:start position:0% +want to reach out Beyond places that I + + + align:start position:0% +want to reach out Beyond places that I +can price to give people + + align:start position:0% +can price to give people + + + align:start position:0% +can price to give people +incentives but it's really hard because + + align:start position:0% +incentives but it's really hard because + + + align:start position:0% +incentives but it's really hard because +you can measure what is emitted you can + + align:start position:0% +you can measure what is emitted you can + + + align:start position:0% +you can measure what is emitted you can +never measure what would have + + align:start position:0% +never measure what would have + + + align:start position:0% +never measure what would have +been we we you could see the same + + align:start position:0% +been we we you could see the same + + + align:start position:0% +been we we you could see the same +problem with forests if you think for + + align:start position:0% +problem with forests if you think for + + + align:start position:0% +problem with forests if you think for +just a minute if I pay you not to cut + + align:start position:0% +just a minute if I pay you not to cut + + + align:start position:0% +just a minute if I pay you not to cut +down a forest does that mean the guy + + align:start position:0% +down a forest does that mean the guy + + + align:start position:0% +down a forest does that mean the guy +across the street cuts his down to + + align:start position:0% +across the street cuts his down to + + + align:start position:0% +across the street cuts his down to +provide the + + align:start position:0% +provide the + + + align:start position:0% +provide the +timber or or what uh and you would never + + align:start position:0% +timber or or what uh and you would never + + + align:start position:0% +timber or or what uh and you would never +have cut it + + align:start position:0% +have cut it + + + align:start position:0% +have cut it +down um or you would have I you know so + + align:start position:0% +down um or you would have I you know so + + + align:start position:0% +down um or you would have I you know so +it's a natural it's a natural model if + + align:start position:0% +it's a natural it's a natural model if + + + align:start position:0% +it's a natural it's a natural model if +everybody was if there were a common + + align:start position:0% +everybody was if there were a common + + + align:start position:0% +everybody was if there were a common +regime a cap and trade or a tax regime + + align:start position:0% +regime a cap and trade or a tax regime + + + align:start position:0% +regime a cap and trade or a tax regime +that would happen automatically easily + + align:start position:0% +that would happen automatically easily + + + align:start position:0% +that would happen automatically easily +and you wouldn't have a measurement + + align:start position:0% +and you wouldn't have a measurement + + + align:start position:0% +and you wouldn't have a measurement +problem + + align:start position:0% +problem + + + align:start position:0% +problem +it's just hard to do it without such a + + align:start position:0% +it's just hard to do it without such a + + + align:start position:0% +it's just hard to do it without such a +thing there us companies there's some + + align:start position:0% +thing there us companies there's some + + + align:start position:0% +thing there us companies there's some +sort of informal trading in carbon + + align:start position:0% +sort of informal trading in carbon + + + align:start position:0% +sort of informal trading in carbon +credits in the US and companies will do + + align:start position:0% +credits in the US and companies will do + + + align:start position:0% +credits in the US and companies will do +stuff like this and get and take credit + + align:start position:0% +stuff like this and get and take credit + + + align:start position:0% +stuff like this and get and take credit +for it perfectly fine activity it's it's + + align:start position:0% +for it perfectly fine activity it's it's + + + align:start position:0% +for it perfectly fine activity it's it's +it's uh uh socially responsible and all + + align:start position:0% +it's uh uh socially responsible and all + + + align:start position:0% +it's uh uh socially responsible and all +that but it's just hard to assess + + align:start position:0% +that but it's just hard to assess + + + align:start position:0% +that but it's just hard to assess +where's the developing Nation resistance + + align:start position:0% +where's the developing Nation resistance + + + align:start position:0% +where's the developing Nation resistance +like they're getting investment why + + align:start position:0% +like they're getting investment why + + + align:start position:0% +like they're getting investment why +would they not want besides the + + align:start position:0% +would they not want besides the + + + align:start position:0% +would they not want besides the +measurement problem I I would see it + + align:start position:0% +measurement problem I I would see it + + + align:start position:0% +measurement problem I I would see it +someone get foreign investment anyways + + align:start position:0% +someone get foreign investment anyways + + + align:start position:0% +someone get foreign investment anyways +and you take out full full page ads in + + align:start position:0% +and you take out full full page ads in + + + align:start position:0% +and you take out full full page ads in +the economy right well you know what + + align:start position:0% +the economy right well you know what + + + align:start position:0% +the economy right well you know what +they're worried about is I you guys got + + align:start position:0% +they're worried about is I you guys got + + + align:start position:0% +they're worried about is I you guys got +rich we want to get rich you guys got + + align:start position:0% +rich we want to get rich you guys got + + + align:start position:0% +rich we want to get rich you guys got +rich burning fossil fuel and you're + + align:start position:0% +rich burning fossil fuel and you're + + + align:start position:0% +rich burning fossil fuel and you're +telling + + align:start position:0% +telling + + + align:start position:0% +telling +us I assume I'm going to hear a bunch of + + align:start position:0% +us I assume I'm going to hear a bunch of + + + align:start position:0% +us I assume I'm going to hear a bunch of +this on Wednesday and Friday from the + + align:start position:0% +this on Wednesday and Friday from the + + + align:start position:0% +this on Wednesday and Friday from the +developing world you're telling us that + + align:start position:0% +developing world you're telling us that + + + align:start position:0% +developing world you're telling us that +you got to do + + align:start position:0% +you got to do + + + align:start position:0% +you got to do +that and you're now leaning on us the + + align:start position:0% +that and you're now leaning on us the + + + align:start position:0% +that and you're now leaning on us the +phrase the fear + + align:start position:0% +phrase the fear + + + align:start position:0% +phrase the fear +isn't that boatloads of investment will + + align:start position:0% +isn't that boatloads of investment will + + + align:start position:0% +isn't that boatloads of investment will +come in and modernize their Factory the + + align:start position:0% +come in and modernize their Factory the + + + align:start position:0% +come in and modernize their Factory the +fear is that you're going to raise the + + align:start position:0% +fear is that you're going to raise the + + + align:start position:0% +fear is that you're going to raise the +price of fuel to my poor people a lot of + + align:start position:0% +price of fuel to my poor people a lot of + + + align:start position:0% +price of fuel to my poor people a lot of +these countries subsidize + + align:start position:0% +these countries subsidize + + + align:start position:0% +these countries subsidize +fuel um and I don't want to take the + + align:start position:0% +fuel um and I don't want to take the + + + align:start position:0% +fuel um and I don't want to take the +political heat from something that + + align:start position:0% +political heat from something that + + + align:start position:0% +political heat from something that +restricts my ability to + + align:start position:0% +restricts my ability to + + + align:start position:0% +restricts my ability to +grow if you're telling me that the + + align:start position:0% +grow if you're telling me that the + + + align:start position:0% +grow if you're telling me that the +Europeans are going to come in and + + align:start position:0% +Europeans are going to come in and + + + align:start position:0% +Europeans are going to come in and +modernize my factories that's swell I + + align:start position:0% +modernize my factories that's swell I + + + align:start position:0% +modernize my factories that's swell I +love it if you're telling me that I have + + align:start position:0% +love it if you're telling me that I have + + + align:start position:0% +love it if you're telling me that I have +to change my policies + + align:start position:0% +to change my policies + + + align:start position:0% +to change my policies +in a way that might slow growth and keep + + align:start position:0% +in a way that might slow growth and keep + + + align:start position:0% +in a way that might slow growth and keep +my people poor I'm not real + + align:start position:0% +my people poor I'm not real + + + align:start position:0% +my people poor I'm not real +excited + + align:start position:0% +excited + + + align:start position:0% +excited +and you can say you know I've been + + align:start position:0% +and you can say you know I've been + + + align:start position:0% +and you can say you know I've been +talking about your grandchildren and + + align:start position:0% +talking about your grandchildren and + + + align:start position:0% +talking about your grandchildren and +great-grandchildren well I mean if your + + align:start position:0% +great-grandchildren well I mean if your + + + align:start position:0% +great-grandchildren well I mean if your +kids are starving today that's a pretty + + align:start position:0% +kids are starving today that's a pretty + + + align:start position:0% +kids are starving today that's a pretty +abstract + + align:start position:0% +abstract + + + align:start position:0% +abstract +argument that's real abstract + + align:start position:0% +argument that's real abstract + + + align:start position:0% +argument that's real abstract +so other comments reactions + + align:start position:0% +so other comments reactions + + + align:start position:0% +so other comments reactions +questions + + align:start position:0% + + + + align:start position:0% + +thoughts yeah um so mostly we've been + + align:start position:0% +thoughts yeah um so mostly we've been + + + align:start position:0% +thoughts yeah um so mostly we've been +talking about about greenhouse gases um + + align:start position:0% +talking about about greenhouse gases um + + + align:start position:0% +talking about about greenhouse gases um +is there any International discussion + + align:start position:0% +is there any International discussion + + + align:start position:0% +is there any International discussion +about other like climate changing forces + + align:start position:0% +about other like climate changing forces + + + align:start position:0% +about other like climate changing forces +like like black carbon or other like + + align:start position:0% +like like black carbon or other like + + + align:start position:0% +like like black carbon or other like +aerosols or is that not not that I'm + + align:start position:0% +aerosols or is that not not that I'm + + + align:start position:0% +aerosols or is that not not that I'm +aware of is there some okay say well I + + align:start position:0% +aware of is there some okay say well I + + + align:start position:0% +aware of is there some okay say well I +mean the state department just a few + + align:start position:0% +mean the state department just a few + + + align:start position:0% +mean the state department just a few +weeks ago announced that uh we would + + align:start position:0% +weeks ago announced that uh we would + + + align:start position:0% +weeks ago announced that uh we would +they will you + + align:start position:0% +they will you + + + align:start position:0% +they will you +want oh you didn't sign a release form + + align:start position:0% +want oh you didn't sign a release form + + + align:start position:0% +want oh you didn't sign a release form +but never mind I release + + align:start position:0% +but never mind I release + + + align:start position:0% +but never mind I release +you and everyone is released out there + + align:start position:0% +you and everyone is released out there + + + align:start position:0% +you and everyone is released out there +in television land okay just a few weeks + + align:start position:0% +in television land okay just a few weeks + + + align:start position:0% +in television land okay just a few weeks +ago the state department announced that + + align:start position:0% +ago the state department announced that + + + align:start position:0% +ago the state department announced that +uh we would be part of and I guess the + + align:start position:0% +uh we would be part of and I guess the + + + align:start position:0% +uh we would be part of and I guess the +leader of an effort to try to reduce + + align:start position:0% +leader of an effort to try to reduce + + + align:start position:0% +leader of an effort to try to reduce +emissions of soot and other shortlived + + align:start position:0% +emissions of soot and other shortlived + + + align:start position:0% +emissions of soot and other shortlived +gases um stuff like methane and + + align:start position:0% +gases um stuff like methane and + + + align:start position:0% +gases um stuff like methane and +tropospheric ozon as well so uh that's a + + align:start position:0% +tropospheric ozon as well so uh that's a + + + align:start position:0% +tropospheric ozon as well so uh that's a +voluntary program um but but there are + + align:start position:0% +voluntary program um but but there are + + + align:start position:0% +voluntary program um but but there are +movements in that direction and there is + + align:start position:0% +movements in that direction and there is + + + align:start position:0% +movements in that direction and there is +actually quite a bit of investment in um + + align:start position:0% +actually quite a bit of investment in um + + + align:start position:0% +actually quite a bit of investment in um +providing uh very much more efficient + + align:start position:0% +providing uh very much more efficient + + + align:start position:0% +providing uh very much more efficient +stoves to people in very poor uh + + align:start position:0% +stoves to people in very poor uh + + + align:start position:0% +stoves to people in very poor uh +countries uh so that they can avoid + + align:start position:0% +countries uh so that they can avoid + + + align:start position:0% +countries uh so that they can avoid +using things like dung and coal and + + align:start position:0% +using things like dung and coal and + + + align:start position:0% +using things like dung and coal and +stuff like that which generates an + + align:start position:0% +stuff like that which generates an + + + align:start position:0% +stuff like that which generates an +enormous amount of pollution so it has + + align:start position:0% +enormous amount of pollution so it has + + + align:start position:0% +enormous amount of pollution so it has +both a health benefit and an efficiency + + align:start position:0% +both a health benefit and an efficiency + + + align:start position:0% +both a health benefit and an efficiency +benit benefit and it also Cuts carbon a + + align:start position:0% +benit benefit and it also Cuts carbon a + + + align:start position:0% +benit benefit and it also Cuts carbon a +little bit but you know realistically + + align:start position:0% +little bit but you know realistically + + + align:start position:0% +little bit but you know realistically +the main motivation is much more + + align:start position:0% +the main motivation is much more + + + align:start position:0% +the main motivation is much more +grounded in + + align:start position:0% +grounded in + + + align:start position:0% +grounded in +soot I + + align:start position:0% +soot I + + + align:start position:0% +soot I +mean one reason not the main reason + + align:start position:0% +mean one reason not the main reason + + + align:start position:0% +mean one reason not the main reason +necessarily to be concerned with black + + align:start position:0% +necessarily to be concerned with black + + + align:start position:0% +necessarily to be concerned with black +carbon emissions is the effect on the + + align:start position:0% +carbon emissions is the effect on the + + + align:start position:0% +carbon emissions is the effect on the +reflectivity right you have a lot of sea + + align:start position:0% +reflectivity right you have a lot of sea + + + align:start position:0% +reflectivity right you have a lot of sea +ice ice tends to reflect black carbon + + align:start position:0% +ice ice tends to reflect black carbon + + + align:start position:0% +ice ice tends to reflect black carbon +tends to absorb so it does matter for + + align:start position:0% +tends to absorb so it does matter for + + + align:start position:0% +tends to absorb so it does matter for +climate but it also matters for what you + + align:start position:0% + + + + align:start position:0% + +Bree there are are lots of international + + align:start position:0% +Bree there are are lots of international + + + align:start position:0% +Bree there are are lots of international +environmental treaties most don't have + + align:start position:0% +environmental treaties most don't have + + + align:start position:0% +environmental treaties most don't have +anything to do with + + align:start position:0% + + + + align:start position:0% + +climate \ No newline at end of file diff --git a/3Mvzp5xvEXA.txt b/3Mvzp5xvEXA.txt new file mode 100644 index 0000000000000000000000000000000000000000..32d5b19635e443e8876286d26b2d4b9464b2c770 --- /dev/null +++ b/3Mvzp5xvEXA.txt @@ -0,0 +1,9467 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT OpenCourseWare continue to + + align:start position:0% +will help MIT OpenCourseWare continue to + + + align:start position:0% +will help MIT OpenCourseWare continue to +offer high quality educational resources + + align:start position:0% +offer high quality educational resources + + + align:start position:0% +offer high quality educational resources +for free + + align:start position:0% +for free + + + align:start position:0% +for free +to make a donation or view additional + + align:start position:0% +to make a donation or view additional + + + align:start position:0% +to make a donation or view additional +materials from hundreds of MIT courses + + align:start position:0% +materials from hundreds of MIT courses + + + align:start position:0% +materials from hundreds of MIT courses +visit MIT opencourseware at ocw.mit.edu + + align:start position:0% +visit MIT opencourseware at ocw.mit.edu + + + align:start position:0% +visit MIT opencourseware at ocw.mit.edu +so I'm going to talk today about a + + align:start position:0% +so I'm going to talk today about a + + + align:start position:0% +so I'm going to talk today about a +couple of things I had a hell of a time + + align:start position:0% +couple of things I had a hell of a time + + + align:start position:0% +couple of things I had a hell of a time +constructing a nice clean narrative arc + + align:start position:0% +constructing a nice clean narrative arc + + + align:start position:0% +constructing a nice clean narrative arc +through everything I wanted to say and + + align:start position:0% +through everything I wanted to say and + + + align:start position:0% +through everything I wanted to say and +so I finally just decided the hell with + + align:start position:0% +so I finally just decided the hell with + + + align:start position:0% +so I finally just decided the hell with +it I'm just gonna be honest there's + + align:start position:0% +it I'm just gonna be honest there's + + + align:start position:0% +it I'm just gonna be honest there's +several different pieces they don't make + + align:start position:0% +several different pieces they don't make + + + align:start position:0% +several different pieces they don't make +a narrative arc that's life I want to + + align:start position:0% +a narrative arc that's life I want to + + + align:start position:0% +a narrative arc that's life I want to +address what I see as a sort of + + align:start position:0% +address what I see as a sort of + + + align:start position:0% +address what I see as a sort of +macroscopic view of the organization of + + align:start position:0% +macroscopic view of the organization of + + + align:start position:0% +macroscopic view of the organization of +the human brain is giving us a kind of + + align:start position:0% +the human brain is giving us a kind of + + + align:start position:0% +the human brain is giving us a kind of +picture of what I'm going to call the + + align:start position:0% +picture of what I'm going to call the + + + align:start position:0% +picture of what I'm going to call the +architecture of human intelligence right + + align:start position:0% +architecture of human intelligence right + + + align:start position:0% +architecture of human intelligence right +we're trying to understand intelligence + + align:start position:0% +we're trying to understand intelligence + + + align:start position:0% +we're trying to understand intelligence +in this class and so I think the overall + + align:start position:0% +in this class and so I think the overall + + + align:start position:0% +in this class and so I think the overall +organization of the human brain in which + + align:start position:0% +organization of the human brain in which + + + align:start position:0% +organization of the human brain in which +we've made a lot of progress in the last + + align:start position:0% +we've made a lot of progress in the last + + + align:start position:0% +we've made a lot of progress in the last +20 years gives us a kind of macro + + align:start position:0% +20 years gives us a kind of macro + + + align:start position:0% +20 years gives us a kind of macro +picture of what the pieces of the system + + align:start position:0% +picture of what the pieces of the system + + + align:start position:0% +picture of what the pieces of the system +are so I'll talk about that and then + + align:start position:0% +are so I'll talk about that and then + + + align:start position:0% +are so I'll talk about that and then +also if I talk fast enough do a kind of + + align:start position:0% +also if I talk fast enough do a kind of + + + align:start position:0% +also if I talk fast enough do a kind of +whirlwind introduction through the basic + + align:start position:0% +whirlwind introduction through the basic + + + align:start position:0% +whirlwind introduction through the basic +methods of human cognitive neuroscience + + align:start position:0% +methods of human cognitive neuroscience + + + align:start position:0% +methods of human cognitive neuroscience +using face recognition as an example to + + align:start position:0% +using face recognition as an example to + + + align:start position:0% +using face recognition as an example to +illustrate what each of the methods can + + align:start position:0% +illustrate what each of the methods can + + + align:start position:0% +illustrate what each of the methods can +and cannot do so that's the agenda it's + + align:start position:0% +and cannot do so that's the agenda it's + + + align:start position:0% +and cannot do so that's the agenda it's +gonna be pretty basic so if you've heard + + align:start position:0% +gonna be pretty basic so if you've heard + + + align:start position:0% +gonna be pretty basic so if you've heard +me speak before you've probably heard a + + align:start position:0% +me speak before you've probably heard a + + + align:start position:0% +me speak before you've probably heard a +lot of this so anyway the key question + + align:start position:0% +lot of this so anyway the key question + + + align:start position:0% +lot of this so anyway the key question +we're trying to address in this course + + align:start position:0% +we're trying to address in this course + + + align:start position:0% +we're trying to address in this course +is how does the brain produce + + align:start position:0% +is how does the brain produce + + + align:start position:0% +is how does the brain produce +intelligent behavior and how may we be + + align:start position:0% +intelligent behavior and how may we be + + + align:start position:0% +intelligent behavior and how may we be +able to replicate that intelligence in + + align:start position:0% +able to replicate that intelligence in + + + align:start position:0% +able to replicate that intelligence in +machines ok so there's of course a + + align:start position:0% +machines ok so there's of course a + + + align:start position:0% +machines ok so there's of course a +million different ways to go at that + + align:start position:0% +million different ways to go at that + + + align:start position:0% +million different ways to go at that +question and you can go at it from a + + align:start position:0% +question and you can go at it from a + + + align:start position:0% +question and you can go at it from a +kind of computational angle a coding + + align:start position:0% +kind of computational angle a coding + + + align:start position:0% +kind of computational angle a coding +perspective from a fine-grained neural + + align:start position:0% +perspective from a fine-grained neural + + + align:start position:0% +perspective from a fine-grained neural +circuit perspective and I need to do + + align:start position:0% +circuit perspective and I need to do + + + align:start position:0% +circuit perspective and I need to do +something that's kind of in-between + + align:start position:0% +something that's kind of in-between + + + align:start position:0% +something that's kind of in-between +because those are the things we can + + align:start position:0% +because those are the things we can + + + align:start position:0% +because those are the things we can +approach in human brains and its really + + align:start position:0% +approach in human brains and its really + + + align:start position:0% +approach in human brains and its really +human intelligence we want to understand + + align:start position:0% +human intelligence we want to understand + + + align:start position:0% +human intelligence we want to understand +I'd say some of human intelligence is a + + align:start position:0% +I'd say some of human intelligence is a + + + align:start position:0% +I'd say some of human intelligence is a +lot of it is things that we share with + + align:start position:0% +lot of it is things that we share with + + + align:start position:0% +lot of it is things that we share with +animals but some of it is not and so I + + align:start position:0% +animals but some of it is not and so I + + + align:start position:0% +animals but some of it is not and so I +think it's important to be able to + + align:start position:0% +think it's important to be able to + + + align:start position:0% +think it's important to be able to +approach this not just from the + + align:start position:0% +approach this not just from the + + + align:start position:0% +approach this not just from the +perspectives of animal research + + align:start position:0% +perspectives of animal research + + + align:start position:0% +perspectives of animal research +magnificent as those methods are but to + + align:start position:0% +magnificent as those methods are but to + + + align:start position:0% +magnificent as those methods are but to +also see what we can learn about human + + align:start position:0% +also see what we can learn about human + + + align:start position:0% +also see what we can learn about human +brains + + align:start position:0% +brains + + + align:start position:0% +brains +okay so I'll talk a bit about the + + align:start position:0% +okay so I'll talk a bit about the + + + align:start position:0% +okay so I'll talk a bit about the +overall functional architecture of the + + align:start position:0% +overall functional architecture of the + + + align:start position:0% +overall functional architecture of the +human brain what are the basic pieces of + + align:start position:0% +human brain what are the basic pieces of + + + align:start position:0% +human brain what are the basic pieces of +the system and then I'll get into some + + align:start position:0% +the system and then I'll get into some + + + align:start position:0% +the system and then I'll get into some +some different methods and what they + + align:start position:0% +some different methods and what they + + + align:start position:0% +some different methods and what they +tell us about about face perception okay + + align:start position:0% +tell us about about face perception okay + + + align:start position:0% +tell us about about face perception okay +so at the most general level we can ask + + align:start position:0% +so at the most general level we can ask + + + align:start position:0% +so at the most general level we can ask +whether human intelligence as people + + align:start position:0% +whether human intelligence as people + + + align:start position:0% +whether human intelligence as people +have been asking for centuries actually + + align:start position:0% +have been asking for centuries actually + + + align:start position:0% +have been asking for centuries actually +whether human intelligence is the + + align:start position:0% +whether human intelligence is the + + + align:start position:0% +whether human intelligence is the +product of a bunch of very special + + align:start position:0% +product of a bunch of very special + + + align:start position:0% +product of a bunch of very special +purpose components each optimized to + + align:start position:0% +purpose components each optimized to + + + align:start position:0% +purpose components each optimized to +solve a specific problem kind of like + + align:start position:0% +solve a specific problem kind of like + + + align:start position:0% +solve a specific problem kind of like +this device here where you have a saw + + align:start position:0% +this device here where you have a saw + + + align:start position:0% +this device here where you have a saw +for cutting wood scissors for cutting + + align:start position:0% +for cutting wood scissors for cutting + + + align:start position:0% +for cutting wood scissors for cutting +paper saws don't work that well on paper + + align:start position:0% +paper saws don't work that well on paper + + + align:start position:0% +paper saws don't work that well on paper +and scissors don't work that well on + + align:start position:0% +and scissors don't work that well on + + + align:start position:0% +and scissors don't work that well on +wood or whether human intelligence is a + + align:start position:0% +wood or whether human intelligence is a + + + align:start position:0% +wood or whether human intelligence is a +product of some were kind of generic + + align:start position:0% +product of some were kind of generic + + + align:start position:0% +product of some were kind of generic +all-purpose computational power that + + align:start position:0% +all-purpose computational power that + + + align:start position:0% +all-purpose computational power that +makes us generically smart without + + align:start position:0% +makes us generically smart without + + + align:start position:0% +makes us generically smart without +optimizing us for any particular tasks + + align:start position:0% +optimizing us for any particular tasks + + + align:start position:0% +optimizing us for any particular tasks +and just to foreshadow the answer as in + + align:start position:0% +and just to foreshadow the answer as in + + + align:start position:0% +and just to foreshadow the answer as in +all questions in psychology the answer + + align:start position:0% +all questions in psychology the answer + + + align:start position:0% +all questions in psychology the answer +is both but we'll do that in some detail + + align:start position:0% +is both but we'll do that in some detail + + + align:start position:0% +is both but we'll do that in some detail +before we get into that who cares and + + align:start position:0% +before we get into that who cares and + + + align:start position:0% +before we get into that who cares and +I'd say first of all this kind of macro + + align:start position:0% +I'd say first of all this kind of macro + + + align:start position:0% +I'd say first of all this kind of macro +level question about functional + + align:start position:0% +level question about functional + + + align:start position:0% +level question about functional +components of the human mind and brain + + align:start position:0% +components of the human mind and brain + + + align:start position:0% +components of the human mind and brain +matters for a bunch of reasons first of + + align:start position:0% +matters for a bunch of reasons first of + + + align:start position:0% +matters for a bunch of reasons first of +all I just think it's one of the most + + align:start position:0% +all I just think it's one of the most + + + align:start position:0% +all I just think it's one of the most +basic questions we can ask about about + + align:start position:0% +basic questions we can ask about about + + + align:start position:0% +basic questions we can ask about about +ourselves about who we are is to ask + + align:start position:0% +ourselves about who we are is to ask + + + align:start position:0% +ourselves about who we are is to ask +what the basic pieces are of our minds + + align:start position:0% +what the basic pieces are of our minds + + + align:start position:0% +what the basic pieces are of our minds +second more pragmatically this kind of + + align:start position:0% +second more pragmatically this kind of + + + align:start position:0% +second more pragmatically this kind of +divide and conquer research strategy has + + align:start position:0% +divide and conquer research strategy has + + + align:start position:0% +divide and conquer research strategy has +been effective in lots of different + + align:start position:0% +been effective in lots of different + + + align:start position:0% +been effective in lots of different +fields that are trying to understand a + + align:start position:0% +fields that are trying to understand a + + + align:start position:0% +fields that are trying to understand a +complex system what do you do with this + + align:start position:0% +complex system what do you do with this + + + align:start position:0% +complex system what do you do with this +incredibly complex system where you just + + align:start position:0% +incredibly complex system where you just + + + align:start position:0% +incredibly complex system where you just +can't even figure out how to get started + + align:start position:0% +can't even figure out how to get started + + + align:start position:0% +can't even figure out how to get started +well one sensible way to get started is + + align:start position:0% +well one sensible way to get started is + + + align:start position:0% +well one sensible way to get started is +first figure out what its pieces are and + + align:start position:0% +first figure out what its pieces are and + + + align:start position:0% +first figure out what its pieces are and +then maybe try to figure out how each of + + align:start position:0% +then maybe try to figure out how each of + + + align:start position:0% +then maybe try to figure out how each of +the pieces work and then maybe someday + + align:start position:0% +the pieces work and then maybe someday + + + align:start position:0% +the pieces work and then maybe someday +maybe not in my lifetime figure out how + + align:start position:0% +maybe not in my lifetime figure out how + + + align:start position:0% +maybe not in my lifetime figure out how +they all work together in some + + align:start position:0% +they all work together in some + + + align:start position:0% +they all work together in some +coordinated fashion and third somewhat + + align:start position:0% +coordinated fashion and third somewhat + + + align:start position:0% +coordinated fashion and third somewhat +more subtly of course we want to know + + align:start position:0% +more subtly of course we want to know + + + align:start position:0% +more subtly of course we want to know +not just what the pieces are but what + + align:start position:0% +not just what the pieces are but what + + + align:start position:0% +not just what the pieces are but what +the computations that are performed in + + align:start position:0% +the computations that are performed in + + + align:start position:0% +the computations that are performed in +each of those pieces and what the + + align:start position:0% +each of those pieces and what the + + + align:start position:0% +each of those pieces and what the +representations extracted + + align:start position:0% +representations extracted + + + align:start position:0% +representations extracted +pease are and I think even just a + + align:start position:0% +pease are and I think even just a + + + align:start position:0% +pease are and I think even just a +functional characterization of the scope + + align:start position:0% +functional characterization of the scope + + + align:start position:0% +functional characterization of the scope +of a particular brain region already + + align:start position:0% +of a particular brain region already + + + align:start position:0% +of a particular brain region already +gives us some important clues about the + + align:start position:0% +gives us some important clues about the + + + align:start position:0% +gives us some important clues about the +kinds of computations that go on there + + align:start position:0% +kinds of computations that go on there + + + align:start position:0% +kinds of computations that go on there +right so if we find that there's a part + + align:start position:0% +right so if we find that there's a part + + + align:start position:0% +right so if we find that there's a part +of the brain that's primarily involved + + align:start position:0% +of the brain that's primarily involved + + + align:start position:0% +of the brain that's primarily involved +in face recognition not in reading + + align:start position:0% +in face recognition not in reading + + + align:start position:0% +in face recognition not in reading +visually presented words recognizing + + align:start position:0% +visually presented words recognizing + + + align:start position:0% +visually presented words recognizing +scenes or recognizing objects that + + align:start position:0% +scenes or recognizing objects that + + + align:start position:0% +scenes or recognizing objects that +already gives us some clues about the + + align:start position:0% +already gives us some clues about the + + + align:start position:0% +already gives us some clues about the +kinds of computations that would be + + align:start position:0% +kinds of computations that would be + + + align:start position:0% +kinds of computations that would be +appropriate for that scope of tasks + + align:start position:0% +appropriate for that scope of tasks + + + align:start position:0% +appropriate for that scope of tasks +right so if you tried to write the code + + align:start position:0% +right so if you tried to write the code + + + align:start position:0% +right so if you tried to write the code +to do that you'd be writing very + + align:start position:0% +to do that you'd be writing very + + + align:start position:0% +to do that you'd be writing very +different code if it only had to do face + + align:start position:0% +different code if it only had to do face + + + align:start position:0% +different code if it only had to do face +recognition versus if it also had to be + + align:start position:0% +recognition versus if it also had to be + + + align:start position:0% +recognition versus if it also had to be +able to recognize words and scenes and + + align:start position:0% +able to recognize words and scenes and + + + align:start position:0% +able to recognize words and scenes and +objects presented visually ok so that's + + align:start position:0% +objects presented visually ok so that's + + + align:start position:0% +objects presented visually ok so that's +my list of the main reasons and of + + align:start position:0% +my list of the main reasons and of + + + align:start position:0% +my list of the main reasons and of +course serve heaps of different ways to + + align:start position:0% +course serve heaps of different ways to + + + align:start position:0% +course serve heaps of different ways to +investigate this question and I'll + + align:start position:0% +investigate this question and I'll + + + align:start position:0% +investigate this question and I'll +mention some of those in the second half + + align:start position:0% +mention some of those in the second half + + + align:start position:0% +mention some of those in the second half +but I want to start with Spearman who + + align:start position:0% +but I want to start with Spearman who + + + align:start position:0% +but I want to start with Spearman who +published a paper in 1904 in the + + align:start position:0% +published a paper in 1904 in the + + + align:start position:0% +published a paper in 1904 in the +American Journal of Psychology this + + align:start position:0% +American Journal of Psychology this + + + align:start position:0% +American Journal of Psychology this +article was sandwiched between a + + align:start position:0% +article was sandwiched between a + + + align:start position:0% +article was sandwiched between a +discussion of the soul and an article on + + align:start position:0% +discussion of the soul and an article on + + + align:start position:0% +discussion of the soul and an article on +the psychology of the English sparrow + + align:start position:0% +the psychology of the English sparrow + + + align:start position:0% +the psychology of the English sparrow +and in this article Spearman did the + + align:start position:0% +and in this article Spearman did the + + + align:start position:0% +and in this article Spearman did the +following low-tech but fascinating thing + + align:start position:0% +following low-tech but fascinating thing + + + align:start position:0% +following low-tech but fascinating thing +he tested a whole bunch of kids in two + + align:start position:0% +he tested a whole bunch of kids in two + + + align:start position:0% +he tested a whole bunch of kids in two +different schools on a wide variety of + + align:start position:0% +different schools on a wide variety of + + + align:start position:0% +different schools on a wide variety of +different tasks and this included + + align:start position:0% +different tasks and this included + + + align:start position:0% +different tasks and this included +scholastic achievement type things he + + align:start position:0% +scholastic achievement type things he + + + align:start position:0% +scholastic achievement type things he +got exam grades from each student and a + + align:start position:0% +got exam grades from each student and a + + + align:start position:0% +got exam grades from each student and a +bunch of different classes and he + + align:start position:0% +bunch of different classes and he + + + align:start position:0% +bunch of different classes and he +measured a whole bunch of other kinds of + + align:start position:0% +measured a whole bunch of other kinds of + + + align:start position:0% +measured a whole bunch of other kinds of +psychological abilities including some + + align:start position:0% +psychological abilities including some + + + align:start position:0% +psychological abilities including some +very kind of psycho physical perceptual + + align:start position:0% +very kind of psycho physical perceptual + + + align:start position:0% +very kind of psycho physical perceptual +discrimination abilities how well could + + align:start position:0% +discrimination abilities how well could + + + align:start position:0% +discrimination abilities how well could +people discriminate the Bryton the + + align:start position:0% +people discriminate the Bryton the + + + align:start position:0% +people discriminate the Bryton the +loudness of two different tones the + + align:start position:0% +loudness of two different tones the + + + align:start position:0% +loudness of two different tones the +brightness of two different flashes of + + align:start position:0% +brightness of two different flashes of + + + align:start position:0% +brightness of two different flashes of +white the weight of two different pieces + + align:start position:0% +white the weight of two different pieces + + + align:start position:0% +white the weight of two different pieces +of stuff and what he found well before I + + align:start position:0% +of stuff and what he found well before I + + + align:start position:0% +of stuff and what he found well before I +tell you what he found what do you what + + align:start position:0% +tell you what he found what do you what + + + align:start position:0% +tell you what he found what do you what +would you expect with this should we + + align:start position:0% +would you expect with this should we + + + align:start position:0% +would you expect with this should we +expect a correlation between your + + align:start position:0% +expect a correlation between your + + + align:start position:0% +expect a correlation between your +ability to discriminate two different + + align:start position:0% +ability to discriminate two different + + + align:start position:0% +ability to discriminate two different +loudness ha's and say your math score in + + align:start position:0% +loudness ha's and say your math score in + + + align:start position:0% +loudness ha's and say your math score in +grade five on a math exam Germans main + + align:start position:0% +grade five on a math exam Germans main + + + align:start position:0% +grade five on a math exam Germans main +result is that most pairs of tasks were + + align:start position:0% +result is that most pairs of tasks were + + + align:start position:0% +result is that most pairs of tasks were +correlated with each other that is if + + align:start position:0% +correlated with each other that is if + + + align:start position:0% +correlated with each other that is if +you were good at one you're good at the + + align:start position:0% +you were good at one you're good at the + + + align:start position:0% +you were good at one you're good at the +others + + align:start position:0% +others + + + align:start position:0% +others +even tasks that seemingly have very + + align:start position:0% +even tasks that seemingly have very + + + align:start position:0% +even tasks that seemingly have very +little to do with each other and this is + + align:start position:0% +little to do with each other and this is + + + align:start position:0% +little to do with each other and this is +the basis of the whole idea of G which + + align:start position:0% +the basis of the whole idea of G which + + + align:start position:0% +the basis of the whole idea of G which +is the general factor which is what led + + align:start position:0% +is the general factor which is what led + + + align:start position:0% +is the general factor which is what led +to the whole idea of IQ and IQ testing + + align:start position:0% +to the whole idea of IQ and IQ testing + + + align:start position:0% +to the whole idea of IQ and IQ testing +and in America we're very uptight about + + align:start position:0% +and in America we're very uptight about + + + align:start position:0% +and in America we're very uptight about +the idea of IQ Brits don't seem to have + + align:start position:0% +the idea of IQ Brits don't seem to have + + + align:start position:0% +the idea of IQ Brits don't seem to have +a problem with this idea they're very + + align:start position:0% +a problem with this idea they're very + + + align:start position:0% +a problem with this idea they're very +enthusiastic about the idea and always + + align:start position:0% +enthusiastic about the idea and always + + + align:start position:0% +enthusiastic about the idea and always +have been but um they aside from all the + + align:start position:0% +have been but um they aside from all the + + + align:start position:0% +have been but um they aside from all the +social uses and misuses of IQ tests the + + align:start position:0% +social uses and misuses of IQ tests the + + + align:start position:0% +social uses and misuses of IQ tests the +point is there's actually a deep + + align:start position:0% +point is there's actually a deep + + + align:start position:0% +point is there's actually a deep +discovery about psychology that Spearman + + align:start position:0% +discovery about psychology that Spearman + + + align:start position:0% +discovery about psychology that Spearman +made from the fact that all of these + + align:start position:0% +made from the fact that all of these + + + align:start position:0% +made from the fact that all of these +tasks were correlated with each other he + + align:start position:0% +tasks were correlated with each other he + + + align:start position:0% +tasks were correlated with each other he +didn't know what it was kind of like + + align:start position:0% +didn't know what it was kind of like + + + align:start position:0% +didn't know what it was kind of like +Gregor Mendel inferring genes without + + align:start position:0% +Gregor Mendel inferring genes without + + + align:start position:0% +Gregor Mendel inferring genes without +knowing anything about molecular biology + + align:start position:0% +knowing anything about molecular biology + + + align:start position:0% +knowing anything about molecular biology +Spearman just inferred there's something + + align:start position:0% +Spearman just inferred there's something + + + align:start position:0% +Spearman just inferred there's something +general about the human intellect such + + align:start position:0% +general about the human intellect such + + + align:start position:0% +general about the human intellect such +that there are these strong correlations + + align:start position:0% +that there are these strong correlations + + + align:start position:0% +that there are these strong correlations +about town across tasks okay so that's G + + align:start position:0% +about town across tasks okay so that's G + + + align:start position:0% +about town across tasks okay so that's G +but less well known about Spearman's + + align:start position:0% +but less well known about Spearman's + + + align:start position:0% +but less well known about Spearman's +work as he also talked about the + + align:start position:0% +work as he also talked about the + + + align:start position:0% +work as he also talked about the +specific factor yes and s was the fact + + align:start position:0% +specific factor yes and s was the fact + + + align:start position:0% +specific factor yes and s was the fact +that although the broad result of his + + align:start position:0% +that although the broad result of his + + + align:start position:0% +that although the broad result of his +experiments was that most pairs of tasks + + align:start position:0% +experiments was that most pairs of tasks + + + align:start position:0% +experiments was that most pairs of tasks +were correlated there were some tasks + + align:start position:0% +were correlated there were some tasks + + + align:start position:0% +were correlated there were some tasks +that weren't so strongly correlated with + + align:start position:0% +that weren't so strongly correlated with + + + align:start position:0% +that weren't so strongly correlated with +others and that you could factor those + + align:start position:0% +others and that you could factor those + + + align:start position:0% +others and that you could factor those +out and discover some mental abilities + + align:start position:0% +out and discover some mental abilities + + + align:start position:0% +out and discover some mental abilities +that weren't just you know broadly + + align:start position:0% +that weren't just you know broadly + + + align:start position:0% +that weren't just you know broadly +shared across subjects and I think this + + align:start position:0% +shared across subjects and I think this + + + align:start position:0% +shared across subjects and I think this +is kind of foreshadows everything that + + align:start position:0% +is kind of foreshadows everything that + + + align:start position:0% +is kind of foreshadows everything that +we see with functional MRI there's a lot + + align:start position:0% +we see with functional MRI there's a lot + + + align:start position:0% +we see with functional MRI there's a lot +of specific essence and there's also + + align:start position:0% +of specific essence and there's also + + + align:start position:0% +of specific essence and there's also +some G and you can see those in + + align:start position:0% +some G and you can see those in + + + align:start position:0% +some G and you can see those in +different brain regions as I will detail + + align:start position:0% +different brain regions as I will detail + + + align:start position:0% +different brain regions as I will detail +next another method was invented by + + align:start position:0% +next another method was invented by + + + align:start position:0% +next another method was invented by +Franz Joseph gall and he argued that + + align:start position:0% +Franz Joseph gall and he argued that + + + align:start position:0% +Franz Joseph gall and he argued that +they're distinct mental faculties that + + align:start position:0% +they're distinct mental faculties that + + + align:start position:0% +they're distinct mental faculties that +live in different parts of the brain + + align:start position:0% +live in different parts of the brain + + + align:start position:0% +live in different parts of the brain +right which i think is more or less + + align:start position:0% +right which i think is more or less + + + align:start position:0% +right which i think is more or less +right as I'll argue but you know Paul + + align:start position:0% +right as I'll argue but you know Paul + + + align:start position:0% +right as I'll argue but you know Paul +lived in the 1700s and he didn't have an + + align:start position:0% +lived in the 1700s and he didn't have an + + + align:start position:0% +lived in the 1700s and he didn't have an +MRI machine so he did the best he could + + align:start position:0% +MRI machine so he did the best he could + + + align:start position:0% +MRI machine so he did the best he could +which wasn't so hot he invented the + + align:start position:0% +which wasn't so hot he invented the + + + align:start position:0% +which wasn't so hot he invented the +infamous method of phrenology he felt + + align:start position:0% +infamous method of phrenology he felt + + + align:start position:0% +infamous method of phrenology he felt +the bumps on the skull and tried to + + align:start position:0% +the bumps on the skull and tried to + + + align:start position:0% +the bumps on the skull and tried to +relate those to specific abilities of + + align:start position:0% +relate those to specific abilities of + + + align:start position:0% +relate those to specific abilities of +different individuals and from this + + align:start position:0% +different individuals and from this + + + align:start position:0% +different individuals and from this +inferred + + align:start position:0% +inferred + + + align:start position:0% +inferred +27 mental faculties my favorites are + + align:start position:0% +27 mental faculties my favorites are + + + align:start position:0% +27 mental faculties my favorites are +amativeness filial piety and veneration + + align:start position:0% +amativeness filial piety and veneration + + + align:start position:0% +amativeness filial piety and veneration +and so you know there's a kernel of the + + align:start position:0% +and so you know there's a kernel of the + + + align:start position:0% +and so you know there's a kernel of the +right idea but kind of the wrong method + + align:start position:0% +right idea but kind of the wrong method + + + align:start position:0% +right idea but kind of the wrong method +and another method that was a you know + + align:start position:0% +and another method that was a you know + + + align:start position:0% +and another method that was a you know +very early one was the method of + + align:start position:0% +very early one was the method of + + + align:start position:0% +very early one was the method of +studying the loss of specific mental + + align:start position:0% +studying the loss of specific mental + + + align:start position:0% +studying the loss of specific mental +abilities after brain damage and so + + align:start position:0% +abilities after brain damage and so + + + align:start position:0% +abilities after brain damage and so +florals whose often credited as being + + align:start position:0% +florals whose often credited as being + + + align:start position:0% +florals whose often credited as being +the first experimental neuroscientist + + align:start position:0% +the first experimental neuroscientist + + + align:start position:0% +the first experimental neuroscientist +went around making lesions in pigeons + + align:start position:0% +went around making lesions in pigeons + + + align:start position:0% +went around making lesions in pigeons +and rabbits and didn't and then testing + + align:start position:0% +and rabbits and didn't and then testing + + + align:start position:0% +and rabbits and didn't and then testing +them on various things and he didn't + + align:start position:0% +them on various things and he didn't + + + align:start position:0% +them on various things and he didn't +really find much difference in what + + align:start position:0% +really find much difference in what + + + align:start position:0% +really find much difference in what +parts of the brain he took out for their + + align:start position:0% +parts of the brain he took out for their + + + align:start position:0% +parts of the brain he took out for their +mental abilities maybe that's because he + + align:start position:0% +mental abilities maybe that's because he + + + align:start position:0% +mental abilities maybe that's because he +wasn't such a hot experimental you know + + align:start position:0% +wasn't such a hot experimental you know + + + align:start position:0% +wasn't such a hot experimental you know +he didn't have great experimental + + align:start position:0% +he didn't have great experimental + + + align:start position:0% +he didn't have great experimental +methods in any case he argued that all + + align:start position:0% +methods in any case he argued that all + + + align:start position:0% +methods in any case he argued that all +sensory and volitional faculties exist + + align:start position:0% +sensory and volitional faculties exist + + + align:start position:0% +sensory and volitional faculties exist +in the cerebral hemispheres and must be + + align:start position:0% +in the cerebral hemispheres and must be + + + align:start position:0% +in the cerebral hemispheres and must be +regarded as occupying concurrently the + + align:start position:0% +regarded as occupying concurrently the + + + align:start position:0% +regarded as occupying concurrently the +same seat in those structures right in + + align:start position:0% +same seat in those structures right in + + + align:start position:0% +same seat in those structures right in +other words everything is on top of + + align:start position:0% +other words everything is on top of + + + align:start position:0% +other words everything is on top of +everything else in the brain okay so + + align:start position:0% +everything else in the brain okay so + + + align:start position:0% +everything else in the brain okay so +that was a sort of you know dominant + + align:start position:0% +that was a sort of you know dominant + + + align:start position:0% +that was a sort of you know dominant +view for a while people thought gold was + + align:start position:0% +view for a while people thought gold was + + + align:start position:0% +view for a while people thought gold was +kind of a crackpot even though he wrote + + align:start position:0% +kind of a crackpot even though he wrote + + + align:start position:0% +kind of a crackpot even though he wrote +very popular books and went around here + + align:start position:0% +very popular books and went around here + + + align:start position:0% +very popular books and went around here +up giving popular lectures at huge + + align:start position:0% +up giving popular lectures at huge + + + align:start position:0% +up giving popular lectures at huge +numbers of people attended the + + align:start position:0% +numbers of people attended the + + + align:start position:0% +numbers of people attended the +respectable intellectual society didn't + + align:start position:0% +respectable intellectual society didn't + + + align:start position:0% +respectable intellectual society didn't +take him seriously in fact the whole + + align:start position:0% +take him seriously in fact the whole + + + align:start position:0% +take him seriously in fact the whole +idea of localization of function wasn't + + align:start position:0% +idea of localization of function wasn't + + + align:start position:0% +idea of localization of function wasn't +taken seriously until Paul Broca a + + align:start position:0% +taken seriously until Paul Broca a + + + align:start position:0% +taken seriously until Paul Broca a +member of the the French Academy stood + + align:start position:0% +member of the the French Academy stood + + + align:start position:0% +member of the the French Academy stood +up in front of the Society of + + align:start position:0% +up in front of the Society of + + + align:start position:0% +up in front of the Society of +anthropology in Paris in 1861 and + + align:start position:0% +anthropology in Paris in 1861 and + + + align:start position:0% +anthropology in Paris in 1861 and +announced that the left frontal lobe is + + align:start position:0% +announced that the left frontal lobe is + + + align:start position:0% +announced that the left frontal lobe is +the seat of speech and this was based on + + align:start position:0% +the seat of speech and this was based on + + + align:start position:0% +the seat of speech and this was based on +his patient tan whose brain is shown + + align:start position:0% +his patient tan whose brain is shown + + + align:start position:0% +his patient tan whose brain is shown +here tan was named tan because that was + + align:start position:0% +here tan was named tan because that was + + + align:start position:0% +here tan was named tan because that was +all he could say after damage to his + + align:start position:0% +all he could say after damage to his + + + align:start position:0% +all he could say after damage to his +left inferior frontal lobe and Broca + + align:start position:0% +left inferior frontal lobe and Broca + + + align:start position:0% +left inferior frontal lobe and Broca +pointed out that tan had lots of other + + align:start position:0% +pointed out that tan had lots of other + + + align:start position:0% +pointed out that tan had lots of other +mental faculties preserved and it was + + align:start position:0% +mental faculties preserved and it was + + + align:start position:0% +mental faculties preserved and it was +simply speech that was disrupted and + + align:start position:0% +simply speech that was disrupted and + + + align:start position:0% +simply speech that was disrupted and +from this was kind of one of the first + + align:start position:0% +from this was kind of one of the first + + + align:start position:0% +from this was kind of one of the first +respectable people to argue for + + align:start position:0% +respectable people to argue for + + + align:start position:0% +respectable people to argue for +localization of function okay so this + + align:start position:0% +localization of function okay so this + + + align:start position:0% +localization of function okay so this +this research program goes on and by the + + align:start position:0% +this research program goes on and by the + + + align:start position:0% +this research program goes on and by the +end of the 20th century there's pretty + + align:start position:0% +end of the 20th century there's pretty + + + align:start position:0% +end of the 20th century there's pretty +much agreement that basic sensory and + + align:start position:0% +much agreement that basic sensory and + + + align:start position:0% +much agreement that basic sensory and +motor functions do exhibit localization + + align:start position:0% +motor functions do exhibit localization + + + align:start position:0% +motor functions do exhibit localization +of function in the brain there are + + align:start position:0% +of function in the brain there are + + + align:start position:0% +of function in the brain there are +different regions for basic visual + + align:start position:0% +different regions for basic visual + + + align:start position:0% +different regions for basic visual +processing auditory + + align:start position:0% +processing auditory + + + align:start position:0% +processing auditory +processing and so forth and that was no + + align:start position:0% +processing and so forth and that was no + + + align:start position:0% +processing and so forth and that was no +longer controversial but the whole + + align:start position:0% +longer controversial but the whole + + + align:start position:0% +longer controversial but the whole +question of whether higher level mental + + align:start position:0% +question of whether higher level mental + + + align:start position:0% +question of whether higher level mental +functions were localized in distinct + + align:start position:0% +functions were localized in distinct + + + align:start position:0% +functions were localized in distinct +parts of the brain was controversial + + align:start position:0% +parts of the brain was controversial + + + align:start position:0% +parts of the brain was controversial +then and remains controversial now and + + align:start position:0% +then and remains controversial now and + + + align:start position:0% +then and remains controversial now and +so it method I'll focus on is functional + + align:start position:0% +so it method I'll focus on is functional + + + align:start position:0% +so it method I'll focus on is functional +MRI because I think it's played a huge + + align:start position:0% +MRI because I think it's played a huge + + + align:start position:0% +MRI because I think it's played a huge +role in addressing this question at this + + align:start position:0% +role in addressing this question at this + + + align:start position:0% +role in addressing this question at this +kind of macroscopic level and I think + + align:start position:0% +kind of macroscopic level and I think + + + align:start position:0% +kind of macroscopic level and I think +you guys know what an MRI machine is in + + align:start position:0% +you guys know what an MRI machine is in + + + align:start position:0% +you guys know what an MRI machine is in +case anybody's been on Mars for a while + + align:start position:0% +case anybody's been on Mars for a while + + + align:start position:0% +case anybody's been on Mars for a while +it the important part is it's measure is + + align:start position:0% +it the important part is it's measure is + + + align:start position:0% +it the important part is it's measure is +a very indirect measure of neural + + align:start position:0% +a very indirect measure of neural + + + align:start position:0% +a very indirect measure of neural +activity by way of a long causal chain + + align:start position:0% +activity by way of a long causal chain + + + align:start position:0% +activity by way of a long causal chain +neurons fire you incur metabolic cost + + align:start position:0% +neurons fire you incur metabolic cost + + + align:start position:0% +neurons fire you incur metabolic cost +and blood flow changes to that region + + align:start position:0% +and blood flow changes to that region + + + align:start position:0% +and blood flow changes to that region +blood flow increase more than + + align:start position:0% +blood flow increase more than + + + align:start position:0% +blood flow increase more than +compensates for oxygen use producing a + + align:start position:0% +compensates for oxygen use producing a + + + align:start position:0% +compensates for oxygen use producing a +local decrease rather than the expected + + align:start position:0% +local decrease rather than the expected + + + align:start position:0% +local decrease rather than the expected +increase in deoxyhemoglobin relative to + + align:start position:0% +increase in deoxyhemoglobin relative to + + + align:start position:0% +increase in deoxyhemoglobin relative to +oxyhemoglobin those two are magnetically + + align:start position:0% +oxyhemoglobin those two are magnetically + + + align:start position:0% +oxyhemoglobin those two are magnetically +different that's what the MRI machine + + align:start position:0% +different that's what the MRI machine + + + align:start position:0% +different that's what the MRI machine +detects it's very indirect so it's + + align:start position:0% +detects it's very indirect so it's + + + align:start position:0% +detects it's very indirect so it's +remarkable it works as well as it does + + align:start position:0% +remarkable it works as well as it does + + + align:start position:0% +remarkable it works as well as it does +and it's currently the best non-invasive + + align:start position:0% +and it's currently the best non-invasive + + + align:start position:0% +and it's currently the best non-invasive +method we have in humans in terms of + + align:start position:0% +method we have in humans in terms of + + + align:start position:0% +method we have in humans in terms of +both spatial and having both spatial + + align:start position:0% +both spatial and having both spatial + + + align:start position:0% +both spatial and having both spatial +while spatial resolution not temporal + + align:start position:0% +while spatial resolution not temporal + + + align:start position:0% +while spatial resolution not temporal +resolution okay so and many of you are + + align:start position:0% +resolution okay so and many of you are + + + align:start position:0% +resolution okay so and many of you are +already diving into the details of some + + align:start position:0% +already diving into the details of some + + + align:start position:0% +already diving into the details of some +of the data we collected but in case + + align:start position:0% +of the data we collected but in case + + + align:start position:0% +of the data we collected but in case +you're on other projects and are coming + + align:start position:0% +you're on other projects and are coming + + + align:start position:0% +you're on other projects and are coming +from other fields the basic format of + + align:start position:0% +from other fields the basic format of + + + align:start position:0% +from other fields the basic format of +the data in a typical functional MRI + + align:start position:0% +the data in a typical functional MRI + + + align:start position:0% +the data in a typical functional MRI +study is you have tens of thousands of + + align:start position:0% +study is you have tens of thousands of + + + align:start position:0% +study is you have tens of thousands of +three-dimensional pixels or voxels that + + align:start position:0% +three-dimensional pixels or voxels that + + + align:start position:0% +three-dimensional pixels or voxels that +you scan and those typically you sample + + align:start position:0% +you scan and those typically you sample + + + align:start position:0% +you scan and those typically you sample +a whole set once every two seconds or so + + align:start position:0% +a whole set once every two seconds or so + + + align:start position:0% +a whole set once every two seconds or so +you can push it and do it every second + + align:start position:0% +you can push it and do it every second + + + align:start position:0% +you can push it and do it every second +or less under special circumstances you + + align:start position:0% +or less under special circumstances you + + + align:start position:0% +or less under special circumstances you +can have more voxels by sampling at + + align:start position:0% +can have more voxels by sampling at + + + align:start position:0% +can have more voxels by sampling at +higher resolution but that's ballpark of + + align:start position:0% +higher resolution but that's ballpark of + + + align:start position:0% +higher resolution but that's ballpark of +the format of the kind of movie you can + + align:start position:0% +the format of the kind of movie you can + + + align:start position:0% +the format of the kind of movie you can +get of brain activity okay so a few + + align:start position:0% +get of brain activity okay so a few + + + align:start position:0% +get of brain activity okay so a few +things about the the method and its + + align:start position:0% +things about the the method and its + + + align:start position:0% +things about the the method and its +limitations because they're really + + align:start position:0% +limitations because they're really + + + align:start position:0% +limitations because they're really +important in terms of what you can learn + + align:start position:0% +important in terms of what you can learn + + + align:start position:0% +important in terms of what you can learn +from + + align:start position:0% +from + + + align:start position:0% +from +functional MRI and what you can't so + + align:start position:0% +functional MRI and what you can't so + + + align:start position:0% +functional MRI and what you can't so +first of all this is a timeline my + + align:start position:0% +first of all this is a timeline my + + + align:start position:0% +first of all this is a timeline my +x-axis even though it's invisible is + + align:start position:0% +x-axis even though it's invisible is + + + align:start position:0% +x-axis even though it's invisible is +time in seconds and so if you imagine + + align:start position:0% +time in seconds and so if you imagine + + + align:start position:0% +time in seconds and so if you imagine +looking at v1 and presenting a brief say + + align:start position:0% +looking at v1 and presenting a brief say + + + align:start position:0% +looking at v1 and presenting a brief say +tenth of a second high contrast flash of + + align:start position:0% +tenth of a second high contrast flash of + + + align:start position:0% +tenth of a second high contrast flash of +a checkerboard what we know from + + align:start position:0% +a checkerboard what we know from + + + align:start position:0% +a checkerboard what we know from +neurophysiology is that neurons fire + + align:start position:0% +neurophysiology is that neurons fire + + + align:start position:0% +neurophysiology is that neurons fire +within a hundred milliseconds of + + align:start position:0% +within a hundred milliseconds of + + + align:start position:0% +within a hundred milliseconds of +official onset the information gets + + align:start position:0% +official onset the information gets + + + align:start position:0% +official onset the information gets +right up there really fast the bold + + align:start position:0% +right up there really fast the bold + + + align:start position:0% +right up there really fast the bold +which stands for blood oxygenation level + + align:start position:0% +which stands for blood oxygenation level + + + align:start position:0% +which stands for blood oxygenation level +dependent or functional MRI response is + + align:start position:0% +dependent or functional MRI response is + + + align:start position:0% +dependent or functional MRI response is +way lagged behind this okay so the + + align:start position:0% +way lagged behind this okay so the + + + align:start position:0% +way lagged behind this okay so the +neurons are firing way over here in this + + align:start position:0% +neurons are firing way over here in this + + + align:start position:0% +neurons are firing way over here in this +graph essentially at time zero a tenth + + align:start position:0% +graph essentially at time zero a tenth + + + align:start position:0% +graph essentially at time zero a tenth +of a second but the MRI response is six + + align:start position:0% +of a second but the MRI response is six + + + align:start position:0% +of a second but the MRI response is six +seconds later okay + + align:start position:0% +seconds later okay + + + align:start position:0% +seconds later okay +so it's really slow and that has a bunch + + align:start position:0% +so it's really slow and that has a bunch + + + align:start position:0% +so it's really slow and that has a bunch +of implications about what we can and + + align:start position:0% +of implications about what we can and + + + align:start position:0% +of implications about what we can and +cannot learn from it so first of all + + align:start position:0% +cannot learn from it so first of all + + + align:start position:0% +cannot learn from it so first of all +because it's so slow we we can't resolve + + align:start position:0% +because it's so slow we we can't resolve + + + align:start position:0% +because it's so slow we we can't resolve +the steps and a computation for fast + + align:start position:0% +the steps and a computation for fast + + + align:start position:0% +the steps and a computation for fast +systems like vision and hearing and + + align:start position:0% +systems like vision and hearing and + + + align:start position:0% +systems like vision and hearing and +language understanding systems for which + + align:start position:0% +language understanding systems for which + + + align:start position:0% +language understanding systems for which +we have dedicated machinery that's + + align:start position:0% +we have dedicated machinery that's + + + align:start position:0% +we have dedicated machinery that's +highly efficient where you can recognize + + align:start position:0% +highly efficient where you can recognize + + + align:start position:0% +highly efficient where you can recognize +the gist of a scene within a quarter of + + align:start position:0% +the gist of a scene within a quarter of + + + align:start position:0% +the gist of a scene within a quarter of +a second of when it flashes on a screen + + align:start position:0% +a second of when it flashes on a screen + + + align:start position:0% +a second of when it flashes on a screen +in front of you that and and similarly + + align:start position:0% +in front of you that and and similarly + + + align:start position:0% +in front of you that and and similarly +you understand the meaning of a sentence + + align:start position:0% +you understand the meaning of a sentence + + + align:start position:0% +you understand the meaning of a sentence +so rapidly that you've already parsed + + align:start position:0% +so rapidly that you've already parsed + + + align:start position:0% +so rapidly that you've already parsed +much of the sentence you know well + + align:start position:0% +much of the sentence you know well + + + align:start position:0% +much of the sentence you know well +before the sentence is over + + align:start position:0% +before the sentence is over + + + align:start position:0% +before the sentence is over +right so these are extremely efficient + + align:start position:0% +right so these are extremely efficient + + + align:start position:0% +right so these are extremely efficient +rapid mental processes that means the + + align:start position:0% +rapid mental processes that means the + + + align:start position:0% +rapid mental processes that means the +component steps in those mental + + align:start position:0% +component steps in those mental + + + align:start position:0% +component steps in those mental +processes happen over ten or a few tens + + align:start position:0% +processes happen over ten or a few tens + + + align:start position:0% +processes happen over ten or a few tens +of milliseconds and we're off way off in + + align:start position:0% +of milliseconds and we're off way off in + + + align:start position:0% +of milliseconds and we're off way off in +temporal resolution with functional MRI + + align:start position:0% +temporal resolution with functional MRI + + + align:start position:0% +temporal resolution with functional MRI +all of those things are squashed + + align:start position:0% +all of those things are squashed + + + align:start position:0% +all of those things are squashed +together on top of each other that's a + + align:start position:0% +together on top of each other that's a + + + align:start position:0% +together on top of each other that's a +drag that's just life we can't see those + + align:start position:0% +drag that's just life we can't see those + + + align:start position:0% +drag that's just life we can't see those +individual component steps with + + align:start position:0% +individual component steps with + + + align:start position:0% +individual component steps with +functional MRI the second thing is that + + align:start position:0% +functional MRI the second thing is that + + + align:start position:0% +functional MRI the second thing is that +the spatial resolution it's the best + + align:start position:0% +the spatial resolution it's the best + + + align:start position:0% +the spatial resolution it's the best +that we have in humans non-invasively + + align:start position:0% +that we have in humans non-invasively + + + align:start position:0% +that we have in humans non-invasively +right now but it's absolutely awful + + align:start position:0% +right now but it's absolutely awful + + + align:start position:0% +right now but it's absolutely awful +compared to what you can do in animals + + align:start position:0% +compared to what you can do in animals + + + align:start position:0% +compared to what you can do in animals +so I miss Jim DeCarlo's talk yesterday + + align:start position:0% +so I miss Jim DeCarlo's talk yesterday + + + align:start position:0% +so I miss Jim DeCarlo's talk yesterday +but um but those methods are spectacular + + align:start position:0% +but um but those methods are spectacular + + + align:start position:0% +but um but those methods are spectacular +you can record from individual neurons + + align:start position:0% +you can record from individual neurons + + + align:start position:0% +you can record from individual neurons +record their precise activity with + + align:start position:0% +record their precise activity with + + + align:start position:0% +record their precise activity with +beautiful + + align:start position:0% +beautiful + + + align:start position:0% +beautiful +information in contrast functional MRI + + align:start position:0% +information in contrast functional MRI + + + align:start position:0% +information in contrast functional MRI +is like you know the dark ages we have + + align:start position:0% +is like you know the dark ages we have + + + align:start position:0% +is like you know the dark ages we have +typically hundreds of thousands of + + align:start position:0% +typically hundreds of thousands of + + + align:start position:0% +typically hundreds of thousands of +neurons in each voxel ok so the real + + align:start position:0% +neurons in each voxel ok so the real + + + align:start position:0% +neurons in each voxel ok so the real +miracle of functional MRI is we ever see + + align:start position:0% +miracle of functional MRI is we ever see + + + align:start position:0% +miracle of functional MRI is we ever see +anything at all rather than just garbage + + align:start position:0% +anything at all rather than just garbage + + + align:start position:0% +anything at all rather than just garbage +because you're summing over so many + + align:start position:0% +because you're summing over so many + + + align:start position:0% +because you're summing over so many +neurons at once and it's just a lucky + + align:start position:0% +neurons at once and it's just a lucky + + + align:start position:0% +neurons at once and it's just a lucky +fact of the organization of the human + + align:start position:0% +fact of the organization of the human + + + align:start position:0% +fact of the organization of the human +brain that you have clusterings of + + align:start position:0% +brain that you have clusterings of + + + align:start position:0% +brain that you have clusterings of +neurons with similar respond selectively + + align:start position:0% +neurons with similar respond selectively + + + align:start position:0% +neurons with similar respond selectively +''tis and similar functions at such a + + align:start position:0% +''tis and similar functions at such a + + + align:start position:0% +''tis and similar functions at such a +macro grain that you can see some stuff + + align:start position:0% +macro grain that you can see some stuff + + + align:start position:0% +macro grain that you can see some stuff +with functional MRI although you miss a + + align:start position:0% +with functional MRI although you miss a + + + align:start position:0% +with functional MRI although you miss a +lot as well the third important limit of + + align:start position:0% +lot as well the third important limit of + + + align:start position:0% +lot as well the third important limit of +functional MRI that comes out of just a + + align:start position:0% +functional MRI that comes out of just a + + + align:start position:0% +functional MRI that comes out of just a +consideration of what the method + + align:start position:0% +consideration of what the method + + + align:start position:0% +consideration of what the method +measures is that you can only really see + + align:start position:0% +measures is that you can only really see + + + align:start position:0% +measures is that you can only really see +differences between conditions with + + align:start position:0% +differences between conditions with + + + align:start position:0% +differences between conditions with +functional MRI the magnitude of the MRI + + align:start position:0% +functional MRI the magnitude of the MRI + + + align:start position:0% +functional MRI the magnitude of the MRI +response in a voxel at a time point is + + align:start position:0% +response in a voxel at a time point is + + + align:start position:0% +response in a voxel at a time point is +meaningless it might be you know 563 and + + align:start position:0% +meaningless it might be you know 563 and + + + align:start position:0% +meaningless it might be you know 563 and +that's all it means nothing right means + + align:start position:0% +that's all it means nothing right means + + + align:start position:0% +that's all it means nothing right means +nothing it's just the bright you know + + align:start position:0% +nothing it's just the bright you know + + + align:start position:0% +nothing it's just the bright you know +the intensity of the MRI signal the only + + align:start position:0% +the intensity of the MRI signal the only + + + align:start position:0% +the intensity of the MRI signal the only +way to make it mean something is to + + align:start position:0% +way to make it mean something is to + + + align:start position:0% +way to make it mean something is to +compare it to something else usually two + + align:start position:0% +compare it to something else usually two + + + align:start position:0% +compare it to something else usually two +different tasks or two different stimuli + + align:start position:0% +different tasks or two different stimuli + + + align:start position:0% +different tasks or two different stimuli +and so you can go far with that but it's + + align:start position:0% +and so you can go far with that but it's + + + align:start position:0% +and so you can go far with that but it's +important to realize you can't translate + + align:start position:0% +important to realize you can't translate + + + align:start position:0% +important to realize you can't translate +it into any kind of absolute measure of + + align:start position:0% +it into any kind of absolute measure of + + + align:start position:0% +it into any kind of absolute measure of +neural activity it's only a relative + + align:start position:0% +neural activity it's only a relative + + + align:start position:0% +neural activity it's only a relative +measure of strength of neural activity + + align:start position:0% +measure of strength of neural activity + + + align:start position:0% +measure of strength of neural activity +between two different two or more + + align:start position:0% +between two different two or more + + + align:start position:0% +between two different two or more +different conditions okay and the final + + align:start position:0% +different conditions okay and the final + + + align:start position:0% +different conditions okay and the final +you know deep limitation of functional + + align:start position:0% +you know deep limitation of functional + + + align:start position:0% +you know deep limitation of functional +MRI is that we don't we use this that's + + align:start position:0% +MRI is that we don't we use this that's + + + align:start position:0% +MRI is that we don't we use this that's +convenient phrase neural activity it's + + align:start position:0% +convenient phrase neural activity it's + + + align:start position:0% +convenient phrase neural activity it's +very convenient because it's extremely + + align:start position:0% +very convenient because it's extremely + + + align:start position:0% +very convenient because it's extremely +vague and fittingly so because we don't + + align:start position:0% +vague and fittingly so because we don't + + + align:start position:0% +vague and fittingly so because we don't +know exactly what kind of neural + + align:start position:0% +know exactly what kind of neural + + + align:start position:0% +know exactly what kind of neural +activity is driving the Bolton response + + align:start position:0% +activity is driving the Bolton response + + + align:start position:0% +activity is driving the Bolton response +it could be spikes or action potentials + + align:start position:0% +it could be spikes or action potentials + + + align:start position:0% +it could be spikes or action potentials +it could be synaptic synaptic activity + + align:start position:0% +it could be synaptic synaptic activity + + + align:start position:0% +it could be synaptic synaptic activity +that doesn't lead to spikes it could be + + align:start position:0% +that doesn't lead to spikes it could be + + + align:start position:0% +that doesn't lead to spikes it could be +tonic inhibition it could be all kinds + + align:start position:0% +tonic inhibition it could be all kinds + + + align:start position:0% +tonic inhibition it could be all kinds +of different things + + align:start position:0% +of different things + + + align:start position:0% +of different things +anything that's metabolically expensive + + align:start position:0% +anything that's metabolically expensive + + + align:start position:0% +anything that's metabolically expensive +is likely to increase the blood blood + + align:start position:0% +is likely to increase the blood blood + + + align:start position:0% +is likely to increase the blood blood +flow response in practice when people + + align:start position:0% +flow response in practice when people + + + align:start position:0% +flow response in practice when people +have looked at it it's very nicely + + align:start position:0% +have looked at it it's very nicely + + + align:start position:0% +have looked at it it's very nicely +correlated with firing rate right with + + align:start position:0% +correlated with firing rate right with + + + align:start position:0% +correlated with firing rate right with +some you know bumps and caveat so you + + align:start position:0% +some you know bumps and caveat so you + + + align:start position:0% +some you know bumps and caveat so you +can never be totally sure but there's + + align:start position:0% +can never be totally sure but there's + + + align:start position:0% +can never be totally sure but there's +it's a pretty good proxy for firing rate + + align:start position:0% +it's a pretty good proxy for firing rate + + + align:start position:0% +it's a pretty good proxy for firing rate +you just need to remember in the back of + + align:start position:0% +you just need to remember in the back of + + + align:start position:0% +you just need to remember in the back of +your mind that it could be other stuff + + align:start position:0% +your mind that it could be other stuff + + + align:start position:0% +your mind that it could be other stuff +to the final very important caveat is + + align:start position:0% +to the final very important caveat is + + + align:start position:0% +to the final very important caveat is +that functional MRI it like like you + + align:start position:0% +that functional MRI it like like you + + + align:start position:0% +that functional MRI it like like you +know most other methods where you're + + align:start position:0% +know most other methods where you're + + + align:start position:0% +know most other methods where you're +just recording neural activity in a + + align:start position:0% +just recording neural activity in a + + + align:start position:0% +just recording neural activity in a +variety of different ways you're just + + align:start position:0% +variety of different ways you're just + + + align:start position:0% +variety of different ways you're just +watching you're not intervening and that + + align:start position:0% +watching you're not intervening and that + + + align:start position:0% +watching you're not intervening and that +means you're not measuring the causal + + align:start position:0% +means you're not measuring the causal + + + align:start position:0% +means you're not measuring the causal +role of the things you measure and + + align:start position:0% +role of the things you measure and + + + align:start position:0% +role of the things you measure and +that's very important because it could + + align:start position:0% +that's very important because it could + + + align:start position:0% +that's very important because it could +be that everything you measure is just + + align:start position:0% +be that everything you measure is just + + + align:start position:0% +be that everything you measure is just +completely epi phenomenal and has + + align:start position:0% +completely epi phenomenal and has + + + align:start position:0% +completely epi phenomenal and has +absolutely nothing to do with behavior + + align:start position:0% +absolutely nothing to do with behavior + + + align:start position:0% +absolutely nothing to do with behavior +okay so in practice that's unlikely that + + align:start position:0% +okay so in practice that's unlikely that + + + align:start position:0% +okay so in practice that's unlikely that +you have all the systemic stuff for no + + align:start position:0% +you have all the systemic stuff for no + + + align:start position:0% +you have all the systemic stuff for no +reason but you need to kind of keep in + + align:start position:0% +reason but you need to kind of keep in + + + align:start position:0% +reason but you need to kind of keep in +mind that functional MRI is not affords + + align:start position:0% +mind that functional MRI is not affords + + + align:start position:0% +mind that functional MRI is not affords +no window at all into the causal role of + + align:start position:0% +no window at all into the causal role of + + + align:start position:0% +no window at all into the causal role of +different regions for that you need to + + align:start position:0% +different regions for that you need to + + + align:start position:0% +different regions for that you need to +complement it with other methods okay + + align:start position:0% +complement it with other methods okay + + + align:start position:0% +complement it with other methods okay +so despite all these limitations I think + + align:start position:0% +so despite all these limitations I think + + + align:start position:0% +so despite all these limitations I think +functional MRI has had a huge impact on + + align:start position:0% +functional MRI has had a huge impact on + + + align:start position:0% +functional MRI has had a huge impact on +the field and in admittedly unbiased but + + align:start position:0% +the field and in admittedly unbiased but + + + align:start position:0% +the field and in admittedly unbiased but +I think it's one of these things where + + align:start position:0% +I think it's one of these things where + + + align:start position:0% +I think it's one of these things where +as it happens you know we get so used to + + align:start position:0% +as it happens you know we get so used to + + + align:start position:0% +as it happens you know we get so used to +a result the minute it gets published it + + align:start position:0% +a result the minute it gets published it + + + align:start position:0% +a result the minute it gets published it +was like oh yeah right these when a + + align:start position:0% +was like oh yeah right these when a + + + align:start position:0% +was like oh yeah right these when a +little movement so what but I think it's + + align:start position:0% +little movement so what but I think it's + + + align:start position:0% +little movement so what but I think it's +important to step back so I made a bunch + + align:start position:0% +important to step back so I made a bunch + + + align:start position:0% +important to step back so I made a bunch +of pictures too to show you why I think + + align:start position:0% +of pictures too to show you why I think + + + align:start position:0% +of pictures too to show you why I think +this is important okay here is + + align:start position:0% +this is important okay here is + + + align:start position:0% +this is important okay here is +Penfield's map functional map of the + + align:start position:0% +Penfield's map functional map of the + + + align:start position:0% +Penfield's map functional map of the +human brain published in nineteen fifty + + align:start position:0% +human brain published in nineteen fifty + + + align:start position:0% +human brain published in nineteen fifty +seven year before I was born and he has + + align:start position:0% +seven year before I was born and he has + + + align:start position:0% +seven year before I was born and he has +six count'em six functional regions + + align:start position:0% +six count'em six functional regions + + + align:start position:0% +six count'em six functional regions +labeled in there you probably can't see + + align:start position:0% +labeled in there you probably can't see + + + align:start position:0% +labeled in there you probably can't see +them but it's the basic sensory and + + align:start position:0% +them but it's the basic sensory and + + + align:start position:0% +them but it's the basic sensory and +motor regions visual cortex auditory + + align:start position:0% +motor regions visual cortex auditory + + + align:start position:0% +motor regions visual cortex auditory +cortex motor cortex speech up here in + + align:start position:0% +cortex motor cortex speech up here in + + + align:start position:0% +cortex motor cortex speech up here in +Broca's area and then my favorite is + + align:start position:0% +Broca's area and then my favorite is + + + align:start position:0% +Broca's area and then my favorite is +this word that's his interpretive nice + + align:start position:0% +this word that's his interpretive nice + + + align:start position:0% +this word that's his interpretive nice +okay anyway this was based on electrical + + align:start position:0% +okay anyway this was based on electrical + + + align:start position:0% +okay anyway this was based on electrical +recording and stimulation in patients + + align:start position:0% +recording and stimulation in patients + + + align:start position:0% +recording and stimulation in patients +with epilepsy who were undergoing brain + + align:start position:0% +with epilepsy who were undergoing brain + + + align:start position:0% +with epilepsy who were undergoing brain +surgery actually a very powerful method + + align:start position:0% +surgery actually a very powerful method + + + align:start position:0% +surgery actually a very powerful method +but that's where it got him he published + + align:start position:0% +but that's where it got him he published + + + align:start position:0% +but that's where it got him he published +this near the end of his career and + + align:start position:0% +this near the end of his career and + + + align:start position:0% +this near the end of his career and +that's nice but it's pretty rudimentary + + align:start position:0% +that's nice but it's pretty rudimentary + + + align:start position:0% +that's nice but it's pretty rudimentary +okay now cut to 1990 immediately before + + align:start position:0% +okay now cut to 1990 immediately before + + + align:start position:0% +okay now cut to 1990 immediately before +the advent advent of functional MRI and + + align:start position:0% +the advent advent of functional MRI and + + + align:start position:0% +the advent advent of functional MRI and +I this is really crude the black + + align:start position:0% +I this is really crude the black + + + align:start position:0% +I this is really crude the black +outlines are the basic sensory and motor + + align:start position:0% +outlines are the basic sensory and motor + + + align:start position:0% +outlines are the basic sensory and motor +regions and I've added a couple of big + + align:start position:0% +regions and I've added a couple of big + + + align:start position:0% +regions and I've added a couple of big +colored blobs for regions that had been + + align:start position:0% +colored blobs for regions that had been + + + align:start position:0% +colored blobs for regions that had been +identified by studying patients with + + align:start position:0% +identified by studying patients with + + + align:start position:0% +identified by studying patients with +brain damage + + align:start position:0% +brain damage + + + align:start position:0% +brain damage +so you know even from broken Wernicke it + + align:start position:0% +so you know even from broken Wernicke it + + + align:start position:0% +so you know even from broken Wernicke it +was known that approximately these + + align:start position:0% +was known that approximately these + + + align:start position:0% +was known that approximately these +regions were involved in language + + align:start position:0% +regions were involved in language + + + align:start position:0% +regions were involved in language +because people with damage there lost + + align:start position:0% +because people with damage there lost + + + align:start position:0% +because people with damage there lost +their language abilities you get whacked + + align:start position:0% +their language abilities you get whacked + + + align:start position:0% +their language abilities you get whacked +in your parietal lobe you have weird + + align:start position:0% +in your parietal lobe you have weird + + + align:start position:0% +in your parietal lobe you have weird +attentional problems like neglecting the + + align:start position:0% +attentional problems like neglecting the + + + align:start position:0% +attentional problems like neglecting the +left half of space and stuff like that + + align:start position:0% +left half of space and stuff like that + + + align:start position:0% +left half of space and stuff like that +if you have damaged somewhere to the + + align:start position:0% +if you have damaged somewhere to the + + + align:start position:0% +if you have damaged somewhere to the +back end of the right hemisphere you + + align:start position:0% +back end of the right hemisphere you + + + align:start position:0% +back end of the right hemisphere you +might lose face recognition ability + + align:start position:0% +might lose face recognition ability + + + align:start position:0% +might lose face recognition ability +these things were known by around 1990 + + align:start position:0% +these things were known by around 1990 + + + align:start position:0% +these things were known by around 1990 +not much else that's basically the + + align:start position:0% +not much else that's basically the + + + align:start position:0% +not much else that's basically the +functional map of the brain 1990 okay + + align:start position:0% +functional map of the brain 1990 okay + + + align:start position:0% +functional map of the brain 1990 okay +let's see may see if it probably seems + + align:start position:0% +let's see may see if it probably seems + + + align:start position:0% +let's see may see if it probably seems +like ancient history to a lot of you but + + align:start position:0% +like ancient history to a lot of you but + + + align:start position:0% +like ancient history to a lot of you but +not to me okay here we are today okay + + align:start position:0% +not to me okay here we are today okay + + + align:start position:0% +not to me okay here we are today okay +there's a lot of stuff we've learned + + align:start position:0% +there's a lot of stuff we've learned + + + align:start position:0% +there's a lot of stuff we've learned +right there are a lot of particular + + align:start position:0% +right there are a lot of particular + + + align:start position:0% +right there are a lot of particular +parts of the human brain which have been + + align:start position:0% +parts of the human brain which have been + + + align:start position:0% +parts of the human brain which have been +whose function has been characterized + + align:start position:0% +whose function has been characterized + + + align:start position:0% +whose function has been characterized +quite precisely not in the sense that we + + align:start position:0% +quite precisely not in the sense that we + + + align:start position:0% +quite precisely not in the sense that we +know the precise circuits in there or + + align:start position:0% +know the precise circuits in there or + + + align:start position:0% +know the precise circuits in there or +that we can very precisely characterize + + align:start position:0% +that we can very precisely characterize + + + align:start position:0% +that we can very precisely characterize +the representations or computations but + + align:start position:0% +the representations or computations but + + + align:start position:0% +the representations or computations but +to the it sense that we know that a + + align:start position:0% +to the it sense that we know that a + + + align:start position:0% +to the it sense that we know that a +region may be very selectively involved + + align:start position:0% +region may be very selectively involved + + + align:start position:0% +region may be very selectively involved +for example in thinking about what other + + align:start position:0% +for example in thinking about what other + + + align:start position:0% +for example in thinking about what other +people are thinking a totally remarkable + + align:start position:0% +people are thinking a totally remarkable + + + align:start position:0% +people are thinking a totally remarkable +result that Rebecca Saxe who discovered + + align:start position:0% +result that Rebecca Saxe who discovered + + + align:start position:0% +result that Rebecca Saxe who discovered +it will tell you about when she's here + + align:start position:0% +it will tell you about when she's here + + + align:start position:0% +it will tell you about when she's here +next week okay so that was completely + + align:start position:0% +next week okay so that was completely + + + align:start position:0% +next week okay so that was completely +unknown even 15 years ago let alone back + + align:start position:0% +unknown even 15 years ago let alone back + + + align:start position:0% +unknown even 15 years ago let alone back +in 1990 and likewise most of these other + + align:start position:0% +in 1990 and likewise most of these other + + + align:start position:0% +in 1990 and likewise most of these other +regions were known only in you know + + align:start position:0% +regions were known only in you know + + + align:start position:0% +regions were known only in you know +either known in the blurrier sense or + + align:start position:0% +either known in the blurrier sense or + + + align:start position:0% +either known in the blurrier sense or +not with this precision so I think even + + align:start position:0% +not with this precision so I think even + + + align:start position:0% +not with this precision so I think even +though this is very limited and it's + + align:start position:0% +though this is very limited and it's + + + align:start position:0% +though this is very limited and it's +kind of step 0 and trying to understand + + align:start position:0% +kind of step 0 and trying to understand + + + align:start position:0% +kind of step 0 and trying to understand +the human brain I think it's important + + align:start position:0% +the human brain I think it's important + + + align:start position:0% +the human brain I think it's important +progress and I think to push a little + + align:start position:0% +progress and I think to push a little + + + align:start position:0% +progress and I think to push a little +farther I'd like to see this as an + + align:start position:0% +farther I'd like to see this as an + + + align:start position:0% +farther I'd like to see this as an +admittedly very blurry but still a + + align:start position:0% +admittedly very blurry but still a + + + align:start position:0% +admittedly very blurry but still a +picture of the architecture of human + + align:start position:0% +picture of the architecture of human + + + align:start position:0% +picture of the architecture of human +intelligence what are the basic pieces + + align:start position:0% +intelligence what are the basic pieces + + + align:start position:0% +intelligence what are the basic pieces +what is it we have in here to work with + + align:start position:0% +what is it we have in here to work with + + + align:start position:0% +what is it we have in here to work with +when we think we have these basic pieces + + align:start position:0% +when we think we have these basic pieces + + + align:start position:0% +when we think we have these basic pieces +a bunch more that haven't been + + align:start position:0% +a bunch more that haven't been + + + align:start position:0% +a bunch more that haven't been +discovered yet + + align:start position:0% +discovered yet + + + align:start position:0% +discovered yet +and a lot more that we need to know + + align:start position:0% +and a lot more that we need to know + + + align:start position:0% +and a lot more that we need to know +about each of these and how they + + align:start position:0% +about each of these and how they + + + align:start position:0% +about each of these and how they +interact and all of that but you know a + + align:start position:0% +interact and all of that but you know a + + + align:start position:0% +interact and all of that but you know a +reasonable beginning ok all right so + + align:start position:0% +reasonable beginning ok all right so + + + align:start position:0% +reasonable beginning ok all right so +that's my story year ok for fun this is + + align:start position:0% +that's my story year ok for fun this is + + + align:start position:0% +that's my story year ok for fun this is +me with a bunch of functional regions + + align:start position:0% +me with a bunch of functional regions + + + align:start position:0% +me with a bunch of functional regions +identified in my brain and so the + + align:start position:0% +identified in my brain and so the + + + align:start position:0% +identified in my brain and so the +argument I'm making here is that the + + align:start position:0% +argument I'm making here is that the + + + align:start position:0% +argument I'm making here is that the +human mind and brain contain + + align:start position:0% +human mind and brain contain + + + align:start position:0% +human mind and brain contain +a set of highly specialized components + + align:start position:0% +a set of highly specialized components + + + align:start position:0% +a set of highly specialized components +each solving a different specific + + align:start position:0% +each solving a different specific + + + align:start position:0% +each solving a different specific +problem and that each of these regions + + align:start position:0% +problem and that each of these regions + + + align:start position:0% +problem and that each of these regions +is present in essentially every normal + + align:start position:0% +is present in essentially every normal + + + align:start position:0% +is present in essentially every normal +person it's just part of the basic + + align:start position:0% +person it's just part of the basic + + + align:start position:0% +person it's just part of the basic +architecture of the human mind and brain + + align:start position:0% +architecture of the human mind and brain + + + align:start position:0% +architecture of the human mind and brain +now this view is pretty simple but + + align:start position:0% +now this view is pretty simple but + + + align:start position:0% +now this view is pretty simple but +nonetheless it's often confused with a + + align:start position:0% +nonetheless it's often confused with a + + + align:start position:0% +nonetheless it's often confused with a +whole bunch of other things that people + + align:start position:0% +whole bunch of other things that people + + + align:start position:0% +whole bunch of other things that people +think are the same thing and that aren't + + align:start position:0% +think are the same thing and that aren't + + + align:start position:0% +think are the same thing and that aren't +so it's starting to drive me insane so + + align:start position:0% +so it's starting to drive me insane so + + + align:start position:0% +so it's starting to drive me insane so +I'm going to take five minutes and go + + align:start position:0% +I'm going to take five minutes and go + + + align:start position:0% +I'm going to take five minutes and go +through the things this does not mean + + align:start position:0% +through the things this does not mean + + + align:start position:0% +through the things this does not mean +and okay I hope this doesn't insult your + + align:start position:0% +and okay I hope this doesn't insult your + + + align:start position:0% +and okay I hope this doesn't insult your +intelligence but it's amazing how in the + + align:start position:0% +intelligence but it's amazing how in the + + + align:start position:0% +intelligence but it's amazing how in the +current literature in the field people + + align:start position:0% +current literature in the field people + + + align:start position:0% +current literature in the field people +conflate these things okay so I'm + + align:start position:0% +conflate these things okay so I'm + + + align:start position:0% +conflate these things okay so I'm +talking about functional specificity + + align:start position:0% +talking about functional specificity + + + align:start position:0% +talking about functional specificity +which is a question of whether this + + align:start position:0% +which is a question of whether this + + + align:start position:0% +which is a question of whether this +particular region right here is engaged + + align:start position:0% +particular region right here is engaged + + + align:start position:0% +particular region right here is engaged +in pretty selectively in just that + + align:start position:0% +in pretty selectively in just that + + + align:start position:0% +in pretty selectively in just that +particular mental process and not lots + + align:start position:0% +particular mental process and not lots + + + align:start position:0% +particular mental process and not lots +of other mental processes okay that's + + align:start position:0% +of other mental processes okay that's + + + align:start position:0% +of other mental processes okay that's +what I mean by functional specificity + + align:start position:0% +what I mean by functional specificity + + + align:start position:0% +what I mean by functional specificity +that's a different idea than anatomical + + align:start position:0% +that's a different idea than anatomical + + + align:start position:0% +that's a different idea than anatomical +specificity anatomical specificity would + + align:start position:0% +specificity anatomical specificity would + + + align:start position:0% +specificity anatomical specificity would +say is only this region that's involved + + align:start position:0% +say is only this region that's involved + + + align:start position:0% +say is only this region that's involved +and nothing else is involved that's a + + align:start position:0% +and nothing else is involved that's a + + + align:start position:0% +and nothing else is involved that's a +different question right how specific is + + align:start position:0% +different question right how specific is + + + align:start position:0% +different question right how specific is +this region versus are there other + + align:start position:0% +this region versus are there other + + + align:start position:0% +this region versus are there other +regions that do something similar also + + align:start position:0% +regions that do something similar also + + + align:start position:0% +regions that do something similar also +an interesting question but a different + + align:start position:0% +an interesting question but a different + + + align:start position:0% +an interesting question but a different +one okay + + align:start position:0% +one okay + + + align:start position:0% +one okay +I'm going to go through this fast so if + + align:start position:0% +I'm going to go through this fast so if + + + align:start position:0% +I'm going to go through this fast so if +any of it doesn't make sense just raise + + align:start position:0% +any of it doesn't make sense just raise + + + align:start position:0% +any of it doesn't make sense just raise +your hand and all explain it work okay + + align:start position:0% +your hand and all explain it work okay + + + align:start position:0% +your hand and all explain it work okay +yet another idea is the necessity of a + + align:start position:0% +yet another idea is the necessity of a + + + align:start position:0% +yet another idea is the necessity of a +brain region for a particular function + + align:start position:0% +brain region for a particular function + + + align:start position:0% +brain region for a particular function +that's actually what we really want to + + align:start position:0% +that's actually what we really want to + + + align:start position:0% +that's actually what we really want to +know what the functional specificity + + align:start position:0% +know what the functional specificity + + + align:start position:0% +know what the functional specificity +question is not just does it only + + align:start position:0% +question is not just does it only + + + align:start position:0% +question is not just does it only +turn-on when you do X but do you + + align:start position:0% +turn-on when you do X but do you + + + align:start position:0% +turn-on when you do X but do you +absolutely need it for X and so that's + + align:start position:0% +absolutely need it for X and so that's + + + align:start position:0% +absolutely need it for X and so that's +actually a central question that's + + align:start position:0% +actually a central question that's + + + align:start position:0% +actually a central question that's +that's closely connected to it's really + + align:start position:0% +that's closely connected to it's really + + + align:start position:0% +that's closely connected to it's really +part of functional specificity this is a + + align:start position:0% +part of functional specificity this is a + + + align:start position:0% +part of functional specificity this is a +causal question it's different from the + + align:start position:0% +causal question it's different from the + + + align:start position:0% +causal question it's different from the +question of sufficiency right it's a + + align:start position:0% +question of sufficiency right it's a + + + align:start position:0% +question of sufficiency right it's a +given rate brain region sufficient for a + + align:start position:0% +given rate brain region sufficient for a + + + align:start position:0% +given rate brain region sufficient for a +mental process well I think that's just + + align:start position:0% +mental process well I think that's just + + + align:start position:0% +mental process well I think that's just +kind of a wrongheaded question because + + align:start position:0% +kind of a wrongheaded question because + + + align:start position:0% +kind of a wrongheaded question because +nothing's ever sufficient it's just kind + + align:start position:0% +nothing's ever sufficient it's just kind + + + align:start position:0% +nothing's ever sufficient it's just kind +of a confused idea I mean what would + + align:start position:0% +of a confused idea I mean what would + + + align:start position:0% +of a confused idea I mean what would +that mean that would mean we excise my + + align:start position:0% +that mean that would mean we excise my + + + align:start position:0% +that mean that would mean we excise my +face area we put it in a dish keep all + + align:start position:0% +face area we put it in a dish keep all + + + align:start position:0% +face area we put it in a dish keep all +the neurons alive let's pretend we could + + align:start position:0% +the neurons alive let's pretend we could + + + align:start position:0% +the neurons alive let's pretend we could +do that I'm sure and Boyden could figure + + align:start position:0% +do that I'm sure and Boyden could figure + + + align:start position:0% +do that I'm sure and Boyden could figure +out how to do that in a weekend and so + + align:start position:0% +out how to do that in a weekend and so + + + align:start position:0% +out how to do that in a weekend and so +we have this thing alive in a dish can + + align:start position:0% +we have this thing alive in a dish can + + + align:start position:0% +we have this thing alive in a dish can +it do face recognition well of course + + align:start position:0% +it do face recognition well of course + + + align:start position:0% +it do face recognition well of course +not you've got to get the information in + + align:start position:0% +not you've got to get the information in + + + align:start position:0% +not you've got to get the information in +there in the right form Hadden if the + + align:start position:0% +there in the right form Hadden if the + + + align:start position:0% +there in the right form Hadden if the +information doesn't get out and inform + + align:start position:0% +information doesn't get out and inform + + + align:start position:0% +information doesn't get out and inform +the rest of a brain it's not doesn't + + align:start position:0% +the rest of a brain it's not doesn't + + + align:start position:0% +the rest of a brain it's not doesn't +how's a face person right so you need + + align:start position:0% +how's a face person right so you need + + + align:start position:0% +how's a face person right so you need +things to be connected up and that you + + align:start position:0% +things to be connected up and that you + + + align:start position:0% +things to be connected up and that you +need lots of other brain regions to be + + align:start position:0% +need lots of other brain regions to be + + + align:start position:0% +need lots of other brain regions to be +involved so let's distinguish whether + + align:start position:0% +involved so let's distinguish whether + + + align:start position:0% +involved so let's distinguish whether +this brain region is function specific + + align:start position:0% +this brain region is function specific + + + align:start position:0% +this brain region is function specific +for a process from whether it's + + align:start position:0% +for a process from whether it's + + + align:start position:0% +for a process from whether it's +sufficient for the whole process of + + align:start position:0% +sufficient for the whole process of + + + align:start position:0% +sufficient for the whole process of +course it's not sufficient okay all + + align:start position:0% +course it's not sufficient okay all + + + align:start position:0% +course it's not sufficient okay all +right I know you guys would never say + + align:start position:0% +right I know you guys would never say + + + align:start position:0% +right I know you guys would never say +anything so dominant okay a question of + + align:start position:0% +anything so dominant okay a question of + + + align:start position:0% +anything so dominant okay a question of +connectivity right so people often say + + align:start position:0% +connectivity right so people often say + + + align:start position:0% +connectivity right so people often say +oh well this this region is part of a + + align:start position:0% +oh well this this region is part of a + + + align:start position:0% +oh well this this region is part of a +network period my reaction is like duh + + align:start position:0% +network period my reaction is like duh + + + align:start position:0% +network period my reaction is like duh +of course it's part of a network + + align:start position:0% +of course it's part of a network + + + align:start position:0% +of course it's part of a network +everything's part of a network in no way + + align:start position:0% +everything's part of a network in no way + + + align:start position:0% +everything's part of a network in no way +does that engage with the question of + + align:start position:0% +does that engage with the question of + + + align:start position:0% +does that engage with the question of +whether that region is functionally + + align:start position:0% +whether that region is functionally + + + align:start position:0% +whether that region is functionally +specific right a functionally specific + + align:start position:0% +specific right a functionally specific + + + align:start position:0% +specific right a functionally specific +region of course is part of a network it + + align:start position:0% +region of course is part of a network it + + + align:start position:0% +region of course is part of a network it +talks to other brain regions those other + + align:start position:0% +talks to other brain regions those other + + + align:start position:0% +talks to other brain regions those other +brain regions may play an important role + + align:start position:0% +brain regions may play an important role + + + align:start position:0% +brain regions may play an important role +in its processing sure at the very least + + align:start position:0% +in its processing sure at the very least + + + align:start position:0% +in its processing sure at the very least +they're necessary for getting the + + align:start position:0% +they're necessary for getting the + + + align:start position:0% +they're necessary for getting the +information in and out and using it okay + + align:start position:0% +information in and out and using it okay + + + align:start position:0% +information in and out and using it okay +okay all right + + align:start position:0% +okay all right + + + align:start position:0% +okay all right +the final thing that people confuse with + + align:start position:0% +the final thing that people confuse with + + + align:start position:0% +the final thing that people confuse with +functional specificity is an anus this + + align:start position:0% +functional specificity is an anus this + + + align:start position:0% +functional specificity is an anus this +is a very different concept right just + + align:start position:0% +is a very different concept right just + + + align:start position:0% +is a very different concept right just +because we have some particular part of + + align:start position:0% +because we have some particular part of + + + align:start position:0% +because we have some particular part of +the brain for which we make it really + + align:start position:0% +the brain for which we make it really + + + align:start position:0% +the brain for which we make it really +strong evidence that it's very + + align:start position:0% +strong evidence that it's very + + + align:start position:0% +strong evidence that it's very +specifically involved in mental process + + align:start position:0% +specifically involved in mental process + + + align:start position:0% +specifically involved in mental process +X that's cool that's important that's + + align:start position:0% +X that's cool that's important that's + + + align:start position:0% +X that's cool that's important that's +completely orthogonal to how it got + + align:start position:0% +completely orthogonal to how it got + + + align:start position:0% +completely orthogonal to how it got +wired up and whether it's innately + + align:start position:0% +wired up and whether it's innately + + + align:start position:0% +wired up and whether it's innately +specified in the genome that whole + + align:start position:0% +specified in the genome that whole + + + align:start position:0% +specified in the genome that whole +circuit or whether that circuit is + + align:start position:0% +circuit or whether that circuit is + + + align:start position:0% +circuit or whether that circuit is +instructed by experience over + + align:start position:0% +instructed by experience over + + + align:start position:0% +instructed by experience over +development or as in the usual case very + + align:start position:0% +development or as in the usual case very + + + align:start position:0% +development or as in the usual case very +complicated combinations of those two + + align:start position:0% +complicated combinations of those two + + + align:start position:0% +complicated combinations of those two +okay so just to remind you that + + align:start position:0% +okay so just to remind you that + + + align:start position:0% +okay so just to remind you that +functional specificity is a different + + align:start position:0% +functional specificity is a different + + + align:start position:0% +functional specificity is a different +question from an anus and one way you + + align:start position:0% +question from an anus and one way you + + + align:start position:0% +question from an anus and one way you +can see that very clearly is to consider + + align:start position:0% +can see that very clearly is to consider + + + align:start position:0% +can see that very clearly is to consider +the case of the visual word form area + + align:start position:0% +the case of the visual word form area + + + align:start position:0% +the case of the visual word form area +about which I'll show you some data in a + + align:start position:0% +about which I'll show you some data in a + + + align:start position:0% +about which I'll show you some data in a +moment the visual word form area + + align:start position:0% +moment the visual word form area + + + align:start position:0% +moment the visual word form area +responds selectively to words and letter + + align:start position:0% +responds selectively to words and letter + + + align:start position:0% +responds selectively to words and letter +strings in an orthography you know not + + align:start position:0% +strings in an orthography you know not + + + align:start position:0% +strings in an orthography you know not +an orthography you don't know it's very + + align:start position:0% +an orthography you don't know it's very + + + align:start position:0% +an orthography you don't know it's very +anatomically stereotyped mine is + + align:start position:0% +anatomically stereotyped mine is + + + align:start position:0% +anatomically stereotyped mine is +approximately right there and so is + + align:start position:0% +approximately right there and so is + + + align:start position:0% +approximately right there and so is +yours in your brain and it responds to + + align:start position:0% +yours in your brain and it responds to + + + align:start position:0% +yours in your brain and it responds to +orthographies you know if you can read + + align:start position:0% +orthographies you know if you can read + + + align:start position:0% +orthographies you know if you can read +Arabic and Hebrew yours also responds + + align:start position:0% +Arabic and Hebrew yours also responds + + + align:start position:0% +Arabic and Hebrew yours also responds +when you look at words in Arabic and + + align:start position:0% +when you look at words in Arabic and + + + align:start position:0% +when you look at words in Arabic and +Hebrew if you can't it doesn't or it + + align:start position:0% +Hebrew if you can't it doesn't or it + + + align:start position:0% +Hebrew if you can't it doesn't or it +responds a whole lot less okay so that's + + align:start position:0% +responds a whole lot less okay so that's + + + align:start position:0% +responds a whole lot less okay so that's +a function of your individual experience + + align:start position:0% +a function of your individual experience + + + align:start position:0% +a function of your individual experience +not your ancestors experience it has + + align:start position:0% +not your ancestors experience it has + + + align:start position:0% +not your ancestors experience it has +strong functional specificity and yet + + align:start position:0% +strong functional specificity and yet + + + align:start position:0% +strong functional specificity and yet +it's functional specificity is not + + align:start position:0% +it's functional specificity is not + + + align:start position:0% +it's functional specificity is not +innate so this idea that I'm taking out + + align:start position:0% +innate so this idea that I'm taking out + + + align:start position:0% +innate so this idea that I'm taking out +here's has become kind of unpopular it's + + align:start position:0% +here's has become kind of unpopular it's + + + align:start position:0% +here's has become kind of unpopular it's +very trendy to say oh of course we know + + align:start position:0% +very trendy to say oh of course we know + + + align:start position:0% +very trendy to say oh of course we know +the brain doesn't have specialized + + align:start position:0% +the brain doesn't have specialized + + + align:start position:0% +the brain doesn't have specialized +components so for example here's from a + + align:start position:0% +components so for example here's from a + + + align:start position:0% +components so for example here's from a +textbook Scotty tell unlike their + + align:start position:0% +textbook Scotty tell unlike their + + + align:start position:0% +textbook Scotty tell unlike their +phrenologist who believe this very + + align:start position:0% +phrenologist who believe this very + + + align:start position:0% +phrenologist who believe this very +stupid idea that very complex traits + + align:start position:0% +stupid idea that very complex traits + + + align:start position:0% +stupid idea that very complex traits +were associated with discrete brain + + align:start position:0% +were associated with discrete brain + + + align:start position:0% +were associated with discrete brain +regions modern researchers recognize + + align:start position:0% +regions modern researchers recognize + + + align:start position:0% +regions modern researchers recognize +that a single brain brain region may + + align:start position:0% +that a single brain brain region may + + + align:start position:0% +that a single brain brain region may +participate in more than one function + + align:start position:0% +participate in more than one function + + + align:start position:0% +participate in more than one function +well he built in the hedge word may so + + align:start position:0% +well he built in the hedge word may so + + + align:start position:0% +well he built in the hedge word may so +we can't really have a fight but you + + align:start position:0% +we can't really have a fight but you + + + align:start position:0% +we can't really have a fight but you +know he's trying to stake out this + + align:start position:0% +know he's trying to stake out this + + + align:start position:0% +know he's trying to stake out this +different view Lisa + + align:start position:0% +different view Lisa + + + align:start position:0% +different view Lisa +Feldman Barrett I haven't met her but + + align:start position:0% +Feldman Barrett I haven't met her but + + + align:start position:0% +Feldman Barrett I haven't met her but +she's driving me insane most recently by + + align:start position:0% +she's driving me insane most recently by + + + align:start position:0% +she's driving me insane most recently by +proclaiming all kinds of things in the + + align:start position:0% +proclaiming all kinds of things in the + + + align:start position:0% +proclaiming all kinds of things in the +New York Times just a few weeks ago + + align:start position:0% +New York Times just a few weeks ago + + + align:start position:0% +New York Times just a few weeks ago +quote in general the workings of the + + align:start position:0% +quote in general the workings of the + + + align:start position:0% +quote in general the workings of the +brain are not one-to-one whereby a given + + align:start position:0% +brain are not one-to-one whereby a given + + + align:start position:0% +brain are not one-to-one whereby a given +region has a distinct psychological + + align:start position:0% +region has a distinct psychological + + + align:start position:0% +region has a distinct psychological +purpose right well she's got Hedge words + + align:start position:0% +purpose right well she's got Hedge words + + + align:start position:0% +purpose right well she's got Hedge words +in general dive we all have hedge words + + align:start position:0% +in general dive we all have hedge words + + + align:start position:0% +in general dive we all have hedge words +but you know she's she's basically what + + align:start position:0% +but you know she's she's basically what + + + align:start position:0% +but you know she's she's basically what +she's reasoning from is the fact that + + align:start position:0% +she's reasoning from is the fact that + + + align:start position:0% +she's reasoning from is the fact that +her data suggests that specific emotions + + align:start position:0% +her data suggests that specific emotions + + + align:start position:0% +her data suggests that specific emotions +don't inhabit specific brain regions + + align:start position:0% +don't inhabit specific brain regions + + + align:start position:0% +don't inhabit specific brain regions +from the idea that the whole brain has + + align:start position:0% +from the idea that the whole brain has + + + align:start position:0% +from the idea that the whole brain has +no localization of function well that's + + align:start position:0% +no localization of function well that's + + + align:start position:0% +no localization of function well that's +idiotic + + align:start position:0% +idiotic + + + align:start position:0% +idiotic +it's just idiotic right okay so I hope + + align:start position:0% +it's just idiotic right okay so I hope + + + align:start position:0% +it's just idiotic right okay so I hope +that people will stop these fast and + + align:start position:0% +that people will stop these fast and + + + align:start position:0% +that people will stop these fast and +loose arguments but here's my favorite + + align:start position:0% +loose arguments but here's my favorite + + + align:start position:0% +loose arguments but here's my favorite +this old coot all I know this is gonna + + align:start position:0% +this old coot all I know this is gonna + + + align:start position:0% +this old coot all I know this is gonna +be on the web and here I am carrying on + + align:start position:0% +be on the web and here I am carrying on + + + align:start position:0% +be on the web and here I am carrying on +is if we have anyway whatever this guy + + align:start position:0% +is if we have anyway whatever this guy + + + align:start position:0% +is if we have anyway whatever this guy +cracks me up + + align:start position:0% +cracks me up + + + align:start position:0% +cracks me up +he's been publishing every year he + + align:start position:0% +he's been publishing every year he + + + align:start position:0% +he's been publishing every year he +publishes another book kind of going + + align:start position:0% +publishes another book kind of going + + + align:start position:0% +publishes another book kind of going +after function I'm right any studies + + align:start position:0% +after function I'm right any studies + + + align:start position:0% +after function I'm right any studies +using brain images that report single + + align:start position:0% +using brain images that report single + + + align:start position:0% +using brain images that report single +areas of activation exclusively + + align:start position:0% +areas of activation exclusively + + + align:start position:0% +areas of activation exclusively +associated with a particular cognitive + + align:start position:0% +associated with a particular cognitive + + + align:start position:0% +associated with a particular cognitive +process should be a priori considered to + + align:start position:0% +process should be a priori considered to + + + align:start position:0% +process should be a priori considered to +be artifacts of the arbitrary threshold + + align:start position:0% +be artifacts of the arbitrary threshold + + + align:start position:0% +be artifacts of the arbitrary threshold +set by the investigators and seriously + + align:start position:0% +set by the investigators and seriously + + + align:start position:0% +set by the investigators and seriously +questioned you go + + align:start position:0% +questioned you go + + + align:start position:0% +questioned you go +so anyway um that's fun anyway my point + + align:start position:0% +so anyway um that's fun anyway my point + + + align:start position:0% +so anyway um that's fun anyway my point +is just that we should engage in the + + align:start position:0% +is just that we should engage in the + + + align:start position:0% +is just that we should engage in the +data right this isn't like an ideology + + align:start position:0% +data right this isn't like an ideology + + + align:start position:0% +data right this isn't like an ideology +where we can just proclaim our opinions + + align:start position:0% +where we can just proclaim our opinions + + + align:start position:0% +where we can just proclaim our opinions +there are data that speak to it so let + + align:start position:0% +there are data that speak to it so let + + + align:start position:0% +there are data that speak to it so let +me show you some of mine okay so what + + align:start position:0% +me show you some of mine okay so what + + + align:start position:0% +me show you some of mine okay so what +would be evidence of functional + + align:start position:0% +would be evidence of functional + + + align:start position:0% +would be evidence of functional +specificity there are lots of ways of + + align:start position:0% +specificity there are lots of ways of + + + align:start position:0% +specificity there are lots of ways of +doing it the way I like to do it is + + align:start position:0% +doing it the way I like to do it is + + + align:start position:0% +doing it the way I like to do it is +something called a functional region of + + align:start position:0% +something called a functional region of + + + align:start position:0% +something called a functional region of +interest method the the problem is that + + align:start position:0% +interest method the the problem is that + + + align:start position:0% +interest method the the problem is that +although there are very systematic + + align:start position:0% +although there are very systematic + + + align:start position:0% +although there are very systematic +regularities in the functional + + align:start position:0% +regularities in the functional + + + align:start position:0% +regularities in the functional +organization of the brain each of these + + align:start position:0% +organization of the brain each of these + + + align:start position:0% +organization of the brain each of these +regions that I'm talking about is in + + align:start position:0% +regions that I'm talking about is in + + + align:start position:0% +regions that I'm talking about is in +approximately the same location in each + + align:start position:0% +approximately the same location in each + + + align:start position:0% +approximately the same location in each +normal subject their actual location + + align:start position:0% +normal subject their actual location + + + align:start position:0% +normal subject their actual location +varies a bit from subject to subject so + + align:start position:0% +varies a bit from subject to subject so + + + align:start position:0% +varies a bit from subject to subject so +if you do the standard thing of aligning + + align:start position:0% +if you do the standard thing of aligning + + + align:start position:0% +if you do the standard thing of aligning +brains and averaging across them you get + + align:start position:0% +brains and averaging across them you get + + + align:start position:0% +brains and averaging across them you get +a lot of mush and yet there isn't much + + align:start position:0% +a lot of mush and yet there isn't much + + + align:start position:0% +a lot of mush and yet there isn't much +mush in each subject individually and so + + align:start position:0% +mush in each subject individually and so + + + align:start position:0% +mush in each subject individually and so +to deal with that problem and to deal + + align:start position:0% +to deal with that problem and to deal + + + align:start position:0% +to deal with that problem and to deal +with a bunch of other problems we use + + align:start position:0% +with a bunch of other problems we use + + + align:start position:0% +with a bunch of other problems we use +something called a functional region of + + align:start position:0% +something called a functional region of + + + align:start position:0% +something called a functional region of +interest method and that means if you + + align:start position:0% +interest method and that means if you + + + align:start position:0% +interest method and that means if you +want to study a given region you find it + + align:start position:0% +want to study a given region you find it + + + align:start position:0% +want to study a given region you find it +in that subject individually and then + + align:start position:0% +in that subject individually and then + + + align:start position:0% +in that subject individually and then +once you've found it with a simple + + align:start position:0% +once you've found it with a simple + + + align:start position:0% +once you've found it with a simple +contrast you want to find a face region + + align:start position:0% +contrast you want to find a face region + + + align:start position:0% +contrast you want to find a face region +you find a region that responds more + + align:start position:0% +you find a region that responds more + + + align:start position:0% +you find a region that responds more +when people look at faces than when they + + align:start position:0% +when people look at faces than when they + + + align:start position:0% +when people look at faces than when they +look at objects now you found it in that + + align:start position:0% +look at objects now you found it in that + + + align:start position:0% +look at objects now you found it in that +subject it's these 85 voxels right there + + align:start position:0% +subject it's these 85 voxels right there + + + align:start position:0% +subject it's these 85 voxels right there +in that subject now we run a new + + align:start position:0% +in that subject now we run a new + + + align:start position:0% +in that subject now we run a new +experiment to test more interesting + + align:start position:0% +experiment to test more interesting + + + align:start position:0% +experiment to test more interesting +questions about it and we measure the + + align:start position:0% +questions about it and we measure the + + + align:start position:0% +questions about it and we measure the +response in those boxes okay that also + + align:start position:0% +response in those boxes okay that also + + + align:start position:0% +response in those boxes okay that also +has the advantage that the data you plot + + align:start position:0% +has the advantage that the data you plot + + + align:start position:0% +has the advantage that the data you plot +and look at it's independent of the way + + align:start position:0% +and look at it's independent of the way + + + align:start position:0% +and look at it's independent of the way +you found those voxels a very important + + align:start position:0% +you found those voxels a very important + + + align:start position:0% +you found those voxels a very important +problem in a lot of functional + + align:start position:0% +problem in a lot of functional + + + align:start position:0% +problem in a lot of functional +neuroimaging where people have non + + align:start position:0% +neuroimaging where people have non + + + align:start position:0% +neuroimaging where people have non +independent statistical problems with + + align:start position:0% +independent statistical problems with + + + align:start position:0% +independent statistical problems with +their data analysis if you have a + + align:start position:0% +their data analysis if you have a + + + align:start position:0% +their data analysis if you have a +functional region of interest that's + + align:start position:0% +functional region of interest that's + + + align:start position:0% +functional region of interest that's +localized independently of the data you + + align:start position:0% +localized independently of the data you + + + align:start position:0% +localized independently of the data you +look at in it you get out of that + + align:start position:0% +look at in it you get out of that + + + align:start position:0% +look at in it you get out of that +problem it's also a huge benefit because + + align:start position:0% +problem it's also a huge benefit because + + + align:start position:0% +problem it's also a huge benefit because +one of the central problems with + + align:start position:0% +one of the central problems with + + + align:start position:0% +one of the central problems with +functional brain imaging which i think + + align:start position:0% +functional brain imaging which i think + + + align:start position:0% +functional brain imaging which i think +has led to the fact that a large percent + + align:start position:0% +has led to the fact that a large percent + + + align:start position:0% +has led to the fact that a large percent +of the published neuroimaging findings + + align:start position:0% +of the published neuroimaging findings + + + align:start position:0% +of the published neuroimaging findings +are probably noise is that they're just + + align:start position:0% +are probably noise is that they're just + + + align:start position:0% +are probably noise is that they're just +too many degrees of freedom you have + + align:start position:0% +too many degrees of freedom you have + + + align:start position:0% +too many degrees of freedom you have +tens of thousands of voxels you have + + align:start position:0% +tens of thousands of voxels you have + + + align:start position:0% +tens of thousands of voxels you have +loads of different places to look and + + align:start position:0% +loads of different places to look and + + + align:start position:0% +loads of different places to look and +ways to analyze your data one of the + + align:start position:0% +ways to analyze your data one of the + + + align:start position:0% +ways to analyze your data one of the +things I love dearly about the + + align:start position:0% +things I love dearly about the + + + align:start position:0% +things I love dearly about the +functional region of interest method is + + align:start position:0% +functional region of interest method is + + + align:start position:0% +functional region of interest method is +that you tie your hands + + align:start position:0% +that you tie your hands + + + align:start position:0% +that you tie your hands +in a really good way right so you're + + align:start position:0% +in a really good way right so you're + + + align:start position:0% +in a really good way right so you're +you're specifying in advance exactly + + align:start position:0% +you're specifying in advance exactly + + + align:start position:0% +you're specifying in advance exactly +where you're gonna look and you specify + + align:start position:0% +where you're gonna look and you specify + + + align:start position:0% +where you're gonna look and you specify +exactly how you're going to quantify the + + align:start position:0% +exactly how you're going to quantify the + + + align:start position:0% +exactly how you're going to quantify the +response and so you have no degrees of + + align:start position:0% +response and so you have no degrees of + + + align:start position:0% +response and so you have no degrees of +freedom and that gives you a huge + + align:start position:0% +freedom and that gives you a huge + + + align:start position:0% +freedom and that gives you a huge +statistical advantage and it means + + align:start position:0% +statistical advantage and it means + + + align:start position:0% +statistical advantage and it means +you're less likely to be inadvertently + + align:start position:0% +you're less likely to be inadvertently + + + align:start position:0% +you're less likely to be inadvertently +publishing papers on noise okay so + + align:start position:0% +publishing papers on noise okay so + + + align:start position:0% +publishing papers on noise okay so +that's the function region of interest + + align:start position:0% +that's the function region of interest + + + align:start position:0% +that's the function region of interest +method here's just we've done loads of + + align:start position:0% +method here's just we've done loads of + + + align:start position:0% +method here's just we've done loads of +these experiments here's just from a + + align:start position:0% +these experiments here's just from a + + + align:start position:0% +these experiments here's just from a +current experiment in my lab being + + align:start position:0% +current experiment in my lab being + + + align:start position:0% +current experiment in my lab being +conducted by Zeynep Sagan she's actually + + align:start position:0% +conducted by Zeynep Sagan she's actually + + + align:start position:0% +conducted by Zeynep Sagan she's actually +looking at connectivity of different + + align:start position:0% +looking at connectivity of different + + + align:start position:0% +looking at connectivity of different +brain regions using a different method I + + align:start position:0% +brain regions using a different method I + + + align:start position:0% +brain regions using a different method I +probably won't have time to talk about + + align:start position:0% +probably won't have time to talk about + + + align:start position:0% +probably won't have time to talk about +it it's very cool but in the process + + align:start position:0% +it it's very cool but in the process + + + align:start position:0% +it it's very cool but in the process +she's run a whole bunch of functional + + align:start position:0% +she's run a whole bunch of functional + + + align:start position:0% +she's run a whole bunch of functional +localizers and so we can look in her + + align:start position:0% +localizers and so we can look in her + + + align:start position:0% +localizers and so we can look in her +data at the response of the fusiform + + align:start position:0% +data at the response of the fusiform + + + align:start position:0% +data at the response of the fusiform +face area to a whole bunch of different + + align:start position:0% +face area to a whole bunch of different + + + align:start position:0% +face area to a whole bunch of different +conditions ok so these are a bunch of + + align:start position:0% +conditions ok so these are a bunch of + + + align:start position:0% +conditions ok so these are a bunch of +auditory and language conditions so okay + + align:start position:0% +auditory and language conditions so okay + + + align:start position:0% +auditory and language conditions so okay +not too surprising it doesn't respond + + align:start position:0% +not too surprising it doesn't respond + + + align:start position:0% +not too surprising it doesn't respond +very much to those they're presented + + align:start position:0% +very much to those they're presented + + + align:start position:0% +very much to those they're presented +auditorily but these are all visual + + align:start position:0% +auditorily but these are all visual + + + align:start position:0% +auditorily but these are all visual +stimuli here the two yellow bars our + + align:start position:0% +stimuli here the two yellow bars our + + + align:start position:0% +stimuli here the two yellow bars our +faces this is line drawings of faces + + align:start position:0% +faces this is line drawings of faces + + + align:start position:0% +faces this is line drawings of faces +this is video clips color video clips of + + align:start position:0% +this is video clips color video clips of + + + align:start position:0% +this is video clips color video clips of +faces strong responses to both and all + + align:start position:0% +faces strong responses to both and all + + + align:start position:0% +faces strong responses to both and all +of these other conditions line drawings + + align:start position:0% +of these other conditions line drawings + + + align:start position:0% +of these other conditions line drawings +of objects movies of objects movies of + + align:start position:0% +of objects movies of objects movies of + + + align:start position:0% +of objects movies of objects movies of +scenes scrambled objects words scrambled + + align:start position:0% +scenes scrambled objects words scrambled + + + align:start position:0% +scenes scrambled objects words scrambled +words bodies all produce much lower + + align:start position:0% +words bodies all produce much lower + + + align:start position:0% +words bodies all produce much lower +responses okay so I would say this is + + align:start position:0% +responses okay so I would say this is + + + align:start position:0% +responses okay so I would say this is +pretty strong selectivity it's been + + align:start position:0% +pretty strong selectivity it's been + + + align:start position:0% +pretty strong selectivity it's been +tested against lots of alternatives only + + align:start position:0% +tested against lots of alternatives only + + + align:start position:0% +tested against lots of alternatives only +a tiny percent of which are shown here + + align:start position:0% +a tiny percent of which are shown here + + + align:start position:0% +a tiny percent of which are shown here +as I mentioned before it's present in + + align:start position:0% +as I mentioned before it's present in + + + align:start position:0% +as I mentioned before it's present in +more or less the same place in pretty + + align:start position:0% +more or less the same place in pretty + + + align:start position:0% +more or less the same place in pretty +much every normal subject I think it's + + align:start position:0% +much every normal subject I think it's + + + align:start position:0% +much every normal subject I think it's +just a basic piece of mental + + align:start position:0% +just a basic piece of mental + + + align:start position:0% +just a basic piece of mental +architecture now this is a very simple + + align:start position:0% +architecture now this is a very simple + + + align:start position:0% +architecture now this is a very simple +univariate measure we're just measuring + + align:start position:0% +univariate measure we're just measuring + + + align:start position:0% +univariate measure we're just measuring +the very crude thing of the overall + + align:start position:0% +the very crude thing of the overall + + + align:start position:0% +the very crude thing of the overall +magnitude of MRI response in that region + + align:start position:0% +magnitude of MRI response in that region + + + align:start position:0% +magnitude of MRI response in that region +to these conditions there are legitimate + + align:start position:0% +to these conditions there are legitimate + + + align:start position:0% +to these conditions there are legitimate +counter arguments to the simple-minded + + align:start position:0% +counter arguments to the simple-minded + + + align:start position:0% +counter arguments to the simple-minded +view I'm putting forth and we should + + align:start position:0% +view I'm putting forth and we should + + + align:start position:0% +view I'm putting forth and we should +consider them I think the most important + + align:start position:0% +consider them I think the most important + + + align:start position:0% +consider them I think the most important +one comes from pattern analysis methods + + align:start position:0% +one comes from pattern analysis methods + + + align:start position:0% +one comes from pattern analysis methods +which I will talk about if I get there + + align:start position:0% +which I will talk about if I get there + + + align:start position:0% +which I will talk about if I get there +and importantly these data don't tell us + + align:start position:0% +and importantly these data don't tell us + + + align:start position:0% +and importantly these data don't tell us +about the causal role of that region it + + align:start position:0% +about the causal role of that region it + + + align:start position:0% +about the causal role of that region it +will return to those however the point + + align:start position:0% +will return to those however the point + + + align:start position:0% +will return to those however the point +is before we blithely say it's not + + align:start position:0% +is before we blithely say it's not + + + align:start position:0% +is before we blithely say it's not +fashionable to talk about functional + + align:start position:0% +fashionable to talk about functional + + + align:start position:0% +fashionable to talk about functional +specificity we need counter arguments to + + align:start position:0% +specificity we need counter arguments to + + + align:start position:0% +specificity we need counter arguments to +the + + align:start position:0% +the + + + align:start position:0% +the +like this okay they're pretty strong and + + align:start position:0% +like this okay they're pretty strong and + + + align:start position:0% +like this okay they're pretty strong and +that you know that's just one example to + + align:start position:0% +that you know that's just one example to + + + align:start position:0% +that you know that's just one example to +show you just a few others from santa's + + align:start position:0% +show you just a few others from santa's + + + align:start position:0% +show you just a few others from santa's +paper okay so this is what I just showed + + align:start position:0% +paper okay so this is what I just showed + + + align:start position:0% +paper okay so this is what I just showed +you but I'm in the same experiment we + + align:start position:0% +you but I'm in the same experiment we + + + align:start position:0% +you but I'm in the same experiment we +can look at other brain regions okay so + + align:start position:0% +can look at other brain regions okay so + + + align:start position:0% +can look at other brain regions okay so +that this is a bottom surface of the of + + align:start position:0% +that this is a bottom surface of the of + + + align:start position:0% +that this is a bottom surface of the of +the brain there so this is the occipital + + align:start position:0% +the brain there so this is the occipital + + + align:start position:0% +the brain there so this is the occipital +pole front of the head bottom of the + + align:start position:0% +pole front of the head bottom of the + + + align:start position:0% +pole front of the head bottom of the +temporal lobe that face area is the + + align:start position:0% +temporal lobe that face area is the + + + align:start position:0% +temporal lobe that face area is the +region in yellow in this subject this + + align:start position:0% +region in yellow in this subject this + + + align:start position:0% +region in yellow in this subject this +purple region is that visual word form + + align:start position:0% +purple region is that visual word form + + + align:start position:0% +purple region is that visual word form +area that I mentioned and here is its + + align:start position:0% +area that I mentioned and here is its + + + align:start position:0% +area that I mentioned and here is its +response magnitude across a whole bunch + + align:start position:0% +response magnitude across a whole bunch + + + align:start position:0% +response magnitude across a whole bunch +of subjects you localizing and then + + align:start position:0% +of subjects you localizing and then + + + align:start position:0% +of subjects you localizing and then +independently testing the purple bars + + align:start position:0% +independently testing the purple bars + + + align:start position:0% +independently testing the purple bars +are when sorry subjects are looking at + + align:start position:0% +are when sorry subjects are looking at + + + align:start position:0% +are when sorry subjects are looking at +visually presented words and again all + + align:start position:0% +visually presented words and again all + + + align:start position:0% +visually presented words and again all +these other conditions faces objects + + align:start position:0% +these other conditions faces objects + + + align:start position:0% +these other conditions faces objects +bodies scenes you know listening to + + align:start position:0% +bodies scenes you know listening to + + + align:start position:0% +bodies scenes you know listening to +words all of those things much lower + + align:start position:0% +words all of those things much lower + + + align:start position:0% +words all of those things much lower +response okay in the same experiment we + + align:start position:0% +response okay in the same experiment we + + + align:start position:0% +response okay in the same experiment we +can also look at a set of regions that + + align:start position:0% +can also look at a set of regions that + + + align:start position:0% +can also look at a set of regions that +respond to speech I mentioned those very + + align:start position:0% +respond to speech I mentioned those very + + + align:start position:0% +respond to speech I mentioned those very +briefly in my introduction a few days + + align:start position:0% +briefly in my introduction a few days + + + align:start position:0% +briefly in my introduction a few days +ago these are regions a number of people + + align:start position:0% +ago these are regions a number of people + + + align:start position:0% +ago these are regions a number of people +have found in this case what we they're + + align:start position:0% +have found in this case what we they're + + + align:start position:0% +have found in this case what we they're +immediately below or lateral to primary + + align:start position:0% +immediately below or lateral to primary + + + align:start position:0% +immediately below or lateral to primary +auditory cortex in humans interestingly + + align:start position:0% +auditory cortex in humans interestingly + + + align:start position:0% +auditory cortex in humans interestingly +situated right between primary auditory + + align:start position:0% +situated right between primary auditory + + + align:start position:0% +situated right between primary auditory +cortex and language sensitive regions + + align:start position:0% +cortex and language sensitive regions + + + align:start position:0% +cortex and language sensitive regions +right between is a set of regions that + + align:start position:0% +right between is a set of regions that + + + align:start position:0% +right between is a set of regions that +respond to the sounds of speech okay not + + align:start position:0% +respond to the sounds of speech okay not + + + align:start position:0% +respond to the sounds of speech okay not +to the content of language but the + + align:start position:0% +to the content of language but the + + + align:start position:0% +to the content of language but the +sounds of speech and so this is when + + align:start position:0% +sounds of speech and so this is when + + + align:start position:0% +sounds of speech and so this is when +people are just going to say this is + + align:start position:0% +people are just going to say this is + + + align:start position:0% +people are just going to say this is +when people are saying stuff like ba da + + align:start position:0% +when people are saying stuff like ba da + + + align:start position:0% +when people are saying stuff like ba da +da ba da cow so they're just lying in + + align:start position:0% +da ba da cow so they're just lying in + + + align:start position:0% +da ba da cow so they're just lying in +the scanner saying ba da da ba da da and + + align:start position:0% +the scanner saying ba da da ba da da and + + + align:start position:0% +the scanner saying ba da da ba da da and +here's when they're tapping their + + align:start position:0% +here's when they're tapping their + + + align:start position:0% +here's when they're tapping their +fingers in a systematic order here's + + align:start position:0% +fingers in a systematic order here's + + + align:start position:0% +fingers in a systematic order here's +when they're listening to sentences + + align:start position:0% +when they're listening to sentences + + + align:start position:0% +when they're listening to sentences +importantly this is when they're + + align:start position:0% +importantly this is when they're + + + align:start position:0% +importantly this is when they're +listening to Jabberwocky + + align:start position:0% +listening to Jabberwocky + + + align:start position:0% +listening to Jabberwocky +gobbledygook that's meaningless okay so + + align:start position:0% +gobbledygook that's meaningless okay so + + + align:start position:0% +gobbledygook that's meaningless okay so +no meaning but phonemes same response + + align:start position:0% +no meaning but phonemes same response + + + align:start position:0% +no meaning but phonemes same response +that's what tells us that this region is + + align:start position:0% +that's what tells us that this region is + + + align:start position:0% +that's what tells us that this region is +involved in processing the sounds of + + align:start position:0% +involved in processing the sounds of + + + align:start position:0% +involved in processing the sounds of +speech not the content of language and + + align:start position:0% +speech not the content of language and + + + align:start position:0% +speech not the content of language and +lo to everything else so other things + + align:start position:0% +lo to everything else so other things + + + align:start position:0% +lo to everything else so other things +moving outside of perceptual regions you + + align:start position:0% +moving outside of perceptual regions you + + + align:start position:0% +moving outside of perceptual regions you +might say okay fine perception is an + + align:start position:0% +might say okay fine perception is an + + + align:start position:0% +might say okay fine perception is an +inherently modular process there's + + align:start position:0% +inherently modular process there's + + + align:start position:0% +inherently modular process there's +different kinds of perceptual problems + + align:start position:0% +different kinds of perceptual problems + + + align:start position:0% +different kinds of perceptual problems +that make sense but high level cognition + + align:start position:0% +that make sense but high level cognition + + + align:start position:0% +that make sense but high level cognition +we wouldn't really have functional + + align:start position:0% +we wouldn't really have functional + + + align:start position:0% +we wouldn't really have functional +specificity for that but oh yes we do + + align:start position:0% +specificity for that but oh yes we do + + + align:start position:0% +specificity for that but oh yes we do +here are some language regions there's a + + align:start position:0% +here are some language regions there's a + + + align:start position:0% +here are some language regions there's a +bunch of them in the temporal and + + align:start position:0% +bunch of them in the temporal and + + + align:start position:0% +bunch of them in the temporal and +frontal lobe that have been known since + + align:start position:0% +frontal lobe that have been known since + + + align:start position:0% +frontal lobe that have been known since +wernicke and Broca but now with + + align:start position:0% +wernicke and Broca but now with + + + align:start position:0% +wernicke and Broca but now with +functional MRI we can identify them in + + align:start position:0% +functional MRI we can identify them in + + + align:start position:0% +functional MRI we can identify them in +individual subjects and go back and + + align:start position:0% +individual subjects and go back and + + + align:start position:0% +individual subjects and go back and +repeatedly query them and say are they + + align:start position:0% +repeatedly query them and say are they + + + align:start position:0% +repeatedly query them and say are they +involved in all of these other mental + + align:start position:0% +involved in all of these other mental + + + align:start position:0% +involved in all of these other mental +processes so this is now the response in + + align:start position:0% +processes so this is now the response in + + + align:start position:0% +processes so this is now the response in +a language region so identified here's a + + align:start position:0% +a language region so identified here's a + + + align:start position:0% +a language region so identified here's a +response when you're listening to + + align:start position:0% +response when you're listening to + + + align:start position:0% +response when you're listening to +sentences this is when you're listening + + align:start position:0% +sentences this is when you're listening + + + align:start position:0% +sentences this is when you're listening +to Jabberwocky + + align:start position:0% +to Jabberwocky + + + align:start position:0% +to Jabberwocky +nonsense strings here's when you're + + align:start position:0% +nonsense strings here's when you're + + + align:start position:0% +nonsense strings here's when you're +saying ba da da ba da da it's not just + + align:start position:0% +saying ba da da ba da da it's not just + + + align:start position:0% +saying ba da da ba da da it's not just +speech sounds here's when you're + + align:start position:0% +speech sounds here's when you're + + + align:start position:0% +speech sounds here's when you're +listening to synthetically decomposed + + align:start position:0% +listening to synthetically decomposed + + + align:start position:0% +listening to synthetically decomposed +speech sounds that are acoustically very + + align:start position:0% +speech sounds that are acoustically very + + + align:start position:0% +speech sounds that are acoustically very +similar to the Jabberwocky speech it's + + align:start position:0% +similar to the Jabberwocky speech it's + + + align:start position:0% +similar to the Jabberwocky speech it's +just not interested in those things it + + align:start position:0% +just not interested in those things it + + + align:start position:0% +just not interested in those things it +seems to be interested in something more + + align:start position:0% +seems to be interested in something more + + + align:start position:0% +seems to be interested in something more +like the meaning of a sentence and just + + align:start position:0% +like the meaning of a sentence and just + + + align:start position:0% +like the meaning of a sentence and just +to show you some other data we have on + + align:start position:0% +to show you some other data we have on + + + align:start position:0% +to show you some other data we have on +this this is data from F Federico who + + align:start position:0% +this this is data from F Federico who + + + align:start position:0% +this this is data from F Federico who +has tested this region now this is sort + + align:start position:0% +has tested this region now this is sort + + + align:start position:0% +has tested this region now this is sort +of roughly Broca's area on the main + + align:start position:0% +of roughly Broca's area on the main + + + align:start position:0% +of roughly Broca's area on the main +mental functions that people have argued + + align:start position:0% +mental functions that people have argued + + + align:start position:0% +mental functions that people have argued +overlap in the brain with language + + align:start position:0% +overlap in the brain with language + + + align:start position:0% +overlap in the brain with language +namely sorry this is probably hard to + + align:start position:0% +namely sorry this is probably hard to + + + align:start position:0% +namely sorry this is probably hard to +see here but arithmetic so we have + + align:start position:0% +see here but arithmetic so we have + + + align:start position:0% +see here but arithmetic so we have +difficult and easy mental arithmetic + + align:start position:0% +difficult and easy mental arithmetic + + + align:start position:0% +difficult and easy mental arithmetic +intact and scrambled music and pink a + + align:start position:0% +intact and scrambled music and pink a + + + align:start position:0% +intact and scrambled music and pink a +bunch of working memory tasks spatial + + align:start position:0% +bunch of working memory tasks spatial + + + align:start position:0% +bunch of working memory tasks spatial +working memory and verbal working memory + + align:start position:0% +working memory and verbal working memory + + + align:start position:0% +working memory and verbal working memory +and a bunch of cognitive control tasks + + align:start position:0% +and a bunch of cognitive control tasks + + + align:start position:0% +and a bunch of cognitive control tasks +just kind of a tension demanding tasks + + align:start position:0% +just kind of a tension demanding tasks + + + align:start position:0% +just kind of a tension demanding tasks +where you have to switch between tasks + + align:start position:0% +where you have to switch between tasks + + + align:start position:0% +where you have to switch between tasks +and stuff like that and here is a + + align:start position:0% +and stuff like that and here is a + + + align:start position:0% +and stuff like that and here is a +response profile in that region reading + + align:start position:0% +response profile in that region reading + + + align:start position:0% +response profile in that region reading +sentences reading non-word strings all + + align:start position:0% +sentences reading non-word strings all + + + align:start position:0% +sentences reading non-word strings all +of those other tasks both the difficult + + align:start position:0% +of those other tasks both the difficult + + + align:start position:0% +of those other tasks both the difficult +and the easy version no response at all + + align:start position:0% +and the easy version no response at all + + + align:start position:0% +and the easy version no response at all +that's extreme functional specificity + + align:start position:0% +that's extreme functional specificity + + + align:start position:0% +that's extreme functional specificity +right it's not that we've tested + + align:start position:0% +right it's not that we've tested + + + align:start position:0% +right it's not that we've tested +everything there's more to be done but + + align:start position:0% +everything there's more to be done but + + + align:start position:0% +everything there's more to be done but +the first pass Quarian of you know do + + align:start position:0% +the first pass Quarian of you know do + + + align:start position:0% +the first pass Quarian of you know do +those language regions engage in all of + + align:start position:0% +those language regions engage in all of + + + align:start position:0% +those language regions engage in all of +these other things that people thought + + align:start position:0% +these other things that people thought + + + align:start position:0% +these other things that people thought +might overlap with language the answer + + align:start position:0% +might overlap with language the answer + + + align:start position:0% +might overlap with language the answer +is no they don't + + align:start position:0% +is no they don't + + + align:start position:0% +is no they don't +right and interest and I think that's + + align:start position:0% +right and interest and I think that's + + + align:start position:0% +right and interest and I think that's +really deep and and interesting because + + align:start position:0% +really deep and and interesting because + + + align:start position:0% +really deep and and interesting because +it means that you know this this basic + + align:start position:0% +it means that you know this this basic + + + align:start position:0% +it means that you know this this basic +question that we all you know start + + align:start position:0% +question that we all you know start + + + align:start position:0% +question that we all you know start +asking ourselves when we're young is + + align:start position:0% +asking ourselves when we're young is + + + align:start position:0% +asking ourselves when we're young is +what is the relationship between + + align:start position:0% +what is the relationship between + + + align:start position:0% +what is the relationship between +language + + align:start position:0% +language + + + align:start position:0% +language +thought I know Liz disagrees with me + + align:start position:0% +thought I know Liz disagrees with me + + + align:start position:0% +thought I know Liz disagrees with me +somewhat on this that's because she's + + align:start position:0% +somewhat on this that's because she's + + + align:start position:0% +somewhat on this that's because she's +very articulate and she doesn't feel the + + align:start position:0% +very articulate and she doesn't feel the + + + align:start position:0% +very articulate and she doesn't feel the +difference between an idea and its + + align:start position:0% +difference between an idea and its + + + align:start position:0% +difference between an idea and its +articulation I'm less articulate it's + + align:start position:0% +articulation I'm less articulate it's + + + align:start position:0% +articulation I'm less articulate it's +very obvious to me they're different + + align:start position:0% +very obvious to me they're different + + + align:start position:0% +very obvious to me they're different +things you know it's not the only reason + + align:start position:0% +things you know it's not the only reason + + + align:start position:0% +things you know it's not the only reason +she has data too and it'd be fun to + + align:start position:0% +she has data too and it'd be fun to + + + align:start position:0% +she has data too and it'd be fun to +discuss but I think there's a vast gulf + + align:start position:0% +discuss but I think there's a vast gulf + + + align:start position:0% +discuss but I think there's a vast gulf +between the two and that all many + + align:start position:0% +between the two and that all many + + + align:start position:0% +between the two and that all many +different aspects of cognition can + + align:start position:0% +different aspects of cognition can + + + align:start position:0% +different aspects of cognition can +proceed just fine without language + + align:start position:0% +proceed just fine without language + + + align:start position:0% +proceed just fine without language +regions and actually the stronger + + align:start position:0% +regions and actually the stronger + + + align:start position:0% +regions and actually the stronger +evidence for that comes not from these + + align:start position:0% +evidence for that comes not from these + + + align:start position:0% +evidence for that comes not from these +functional MRI data striking as I think + + align:start position:0% +functional MRI data striking as I think + + + align:start position:0% +functional MRI data striking as I think +they are but from patient data so + + align:start position:0% +they are but from patient data so + + + align:start position:0% +they are but from patient data so +rosemary Varley and England has been + + align:start position:0% +rosemary Varley and England has been + + + align:start position:0% +rosemary Varley and England has been +testing patients with global aphasia + + align:start position:0% +testing patients with global aphasia + + + align:start position:0% +testing patients with global aphasia +this is this very tragic horrible thing + + align:start position:0% +this is this very tragic horrible thing + + + align:start position:0% +this is this very tragic horrible thing +that happens in patients who have + + align:start position:0% +that happens in patients who have + + + align:start position:0% +that happens in patients who have +massive left hemisphere strokes that + + align:start position:0% +massive left hemisphere strokes that + + + align:start position:0% +massive left hemisphere strokes that +pretty much take out essentially all of + + align:start position:0% +pretty much take out essentially all of + + + align:start position:0% +pretty much take out essentially all of +their language abilities those people + + align:start position:0% +their language abilities those people + + + align:start position:0% +their language abilities those people +she has shown are intact in their + + align:start position:0% +she has shown are intact in their + + + align:start position:0% +she has shown are intact in their +navigation abilities their arithmetic + + align:start position:0% +navigation abilities their arithmetic + + + align:start position:0% +navigation abilities their arithmetic +abilities their ability to solve logic + + align:start position:0% +abilities their ability to solve logic + + + align:start position:0% +abilities their ability to solve logic +problems their ability to think about + + align:start position:0% +problems their ability to think about + + + align:start position:0% +problems their ability to think about +what other people are thinking their + + align:start position:0% +what other people are thinking their + + + align:start position:0% +what other people are thinking their +ability to appreciate music and so on + + align:start position:0% +ability to appreciate music and so on + + + align:start position:0% +ability to appreciate music and so on +and so forth so I think there's really a + + align:start position:0% +and so forth so I think there's really a + + + align:start position:0% +and so forth so I think there's really a +very big difference between a major part + + align:start position:0% +very big difference between a major part + + + align:start position:0% +very big difference between a major part +of the system that you need to + + align:start position:0% +of the system that you need to + + + align:start position:0% +of the system that you need to +understand the meaning of a sentence and + + align:start position:0% +understand the meaning of a sentence and + + + align:start position:0% +understand the meaning of a sentence and +all of those other aspects of thought + + align:start position:0% +all of those other aspects of thought + + + align:start position:0% +all of those other aspects of thought +this is just showing you what I mean by + + align:start position:0% +this is just showing you what I mean by + + + align:start position:0% +this is just showing you what I mean by +functional specificity what the evidence + + align:start position:0% +functional specificity what the evidence + + + align:start position:0% +functional specificity what the evidence +what the basic first-order evidence is + + align:start position:0% +what the basic first-order evidence is + + + align:start position:0% +what the basic first-order evidence is +and these are just the regions that we + + align:start position:0% +and these are just the regions that we + + + align:start position:0% +and these are just the regions that we +happen to have in this study so I could + + align:start position:0% +happen to have in this study so I could + + + align:start position:0% +happen to have in this study so I could +make a new slide but for lots of other + + align:start position:0% +make a new slide but for lots of other + + + align:start position:0% +make a new slide but for lots of other +perceptual and cognitive functions + + align:start position:0% +perceptual and cognitive functions + + + align:start position:0% +perceptual and cognitive functions +people have found quite specific brain + + align:start position:0% +people have found quite specific brain + + + align:start position:0% +people have found quite specific brain +regions for perceiving bodies and scenes + + align:start position:0% +regions for perceiving bodies and scenes + + + align:start position:0% +regions for perceiving bodies and scenes +of course motion the area MT has been + + align:start position:0% +of course motion the area MT has been + + + align:start position:0% +of course motion the area MT has been +studied for a long time + + align:start position:0% +studied for a long time + + + align:start position:0% +studied for a long time +regions that are quite quite + + align:start position:0% +regions that are quite quite + + + align:start position:0% +regions that are quite quite +specifically involved in processing + + align:start position:0% +specifically involved in processing + + + align:start position:0% +specifically involved in processing +shape we've been studying color + + align:start position:0% +shape we've been studying color + + + align:start position:0% +shape we've been studying color +processing regions recently they're not + + align:start position:0% +processing regions recently they're not + + + align:start position:0% +processing regions recently they're not +as selective for color as some of these + + align:start position:0% +as selective for color as some of these + + + align:start position:0% +as selective for color as some of these +other regions but they're very + + align:start position:0% +other regions but they're very + + + align:start position:0% +other regions but they're very +anatomically consistent and things I + + align:start position:0% +anatomically consistent and things I + + + align:start position:0% +anatomically consistent and things I +mentioned before in my brief + + align:start position:0% +mentioned before in my brief + + + align:start position:0% +mentioned before in my brief +introduction regions that are + + align:start position:0% +introduction regions that are + + + align:start position:0% +introduction regions that are +specifically involved in processing + + align:start position:0% +specifically involved in processing + + + align:start position:0% +specifically involved in processing +pitch information and music information + + align:start position:0% +pitch information and music information + + + align:start position:0% +pitch information and music information +and as you'll hear next week from our + + align:start position:0% +and as you'll hear next week from our + + + align:start position:0% +and as you'll hear next week from our +Rebecca Saxe theory of mind or thinking + + align:start position:0% +Rebecca Saxe theory of mind or thinking + + + align:start position:0% +Rebecca Saxe theory of mind or thinking +about other people's thoughts and so + + align:start position:0% +about other people's thoughts and so + + + align:start position:0% +about other people's thoughts and so +there's + + align:start position:0% +there's + + + align:start position:0% +there's +quite a litany of mental functions that + + align:start position:0% +quite a litany of mental functions that + + + align:start position:0% +quite a litany of mental functions that +have brain regions that are quite + + align:start position:0% +have brain regions that are quite + + + align:start position:0% +have brain regions that are quite +specifically engaged that mental + + align:start position:0% +specifically engaged that mental + + + align:start position:0% +specifically engaged that mental +function and each of these to varying + + align:start position:0% +function and each of these to varying + + + align:start position:0% +function and each of these to varying +degrees but to you know some appreciable + + align:start position:0% +degrees but to you know some appreciable + + + align:start position:0% +degrees but to you know some appreciable +degree have corroborating evidence from + + align:start position:0% +degree have corroborating evidence from + + + align:start position:0% +degree have corroborating evidence from +patients who have that specific deficit + + align:start position:0% +patients who have that specific deficit + + + align:start position:0% +patients who have that specific deficit +so that shows that each of these has is + + align:start position:0% +so that shows that each of these has is + + + align:start position:0% +so that shows that each of these has is +likely to be not only activated during + + align:start position:0% +likely to be not only activated during + + + align:start position:0% +likely to be not only activated during +but causally involved in its mental + + align:start position:0% +but causally involved in its mental + + + align:start position:0% +but causally involved in its mental +function and as I mentioned there are + + align:start position:0% +function and as I mentioned there are + + + align:start position:0% +function and as I mentioned there are +actually good counter arguments to some + + align:start position:0% +actually good counter arguments to some + + + align:start position:0% +actually good counter arguments to some +of the things I've been making that are + + align:start position:0% +of the things I've been making that are + + + align:start position:0% +of the things I've been making that are +worth discussing I think the pattern + + align:start position:0% +worth discussing I think the pattern + + + align:start position:0% +worth discussing I think the pattern +analysis data is the strongest oh and I + + align:start position:0% +analysis data is the strongest oh and I + + + align:start position:0% +analysis data is the strongest oh and I +do need to take a few more minutes just + + align:start position:0% +do need to take a few more minutes just + + + align:start position:0% +do need to take a few more minutes just +like five or something okay + + align:start position:0% +like five or something okay + + + align:start position:0% +like five or something okay +so all of that's to say so here's you + + align:start position:0% +so all of that's to say so here's you + + + align:start position:0% +so all of that's to say so here's you +know roughly where we are now there are + + align:start position:0% +know roughly where we are now there are + + + align:start position:0% +know roughly where we are now there are +counter arguments but loose talk about + + align:start position:0% +counter arguments but loose talk about + + + align:start position:0% +counter arguments but loose talk about +oh there's no localization of function + + align:start position:0% +oh there's no localization of function + + + align:start position:0% +oh there's no localization of function +in the brain you got engaged with this + + align:start position:0% +in the brain you got engaged with this + + + align:start position:0% +in the brain you got engaged with this +at first and give me a serious + + align:start position:0% +at first and give me a serious + + + align:start position:0% +at first and give me a serious +counter-argument right okay finally I + + align:start position:0% +counter-argument right okay finally I + + + align:start position:0% +counter-argument right okay finally I +want to say that though it's not that + + align:start position:0% +want to say that though it's not that + + + align:start position:0% +want to say that though it's not that +the whole brain is like this right there + + align:start position:0% +the whole brain is like this right there + + + align:start position:0% +the whole brain is like this right there +are it's there there big gray patches + + align:start position:0% +are it's there there big gray patches + + + align:start position:0% +are it's there there big gray patches +where we haven't figured out what it's + + align:start position:0% +where we haven't figured out what it's + + + align:start position:0% +where we haven't figured out what it's +doing but there are also substantial + + align:start position:0% +doing but there are also substantial + + + align:start position:0% +doing but there are also substantial +patches that are have already been shown + + align:start position:0% +patches that are have already been shown + + + align:start position:0% +patches that are have already been shown +to be in some sense the opposite of this + + align:start position:0% +to be in some sense the opposite of this + + + align:start position:0% +to be in some sense the opposite of this +region used in almost any difficult task + + align:start position:0% +region used in almost any difficult task + + + align:start position:0% +region used in almost any difficult task +you do at all and I think this is a very + + align:start position:0% +you do at all and I think this is a very + + + align:start position:0% +you do at all and I think this is a very +interesting part of the whole story of + + align:start position:0% +interesting part of the whole story of + + + align:start position:0% +interesting part of the whole story of +the architecture of intelligence so I'm + + align:start position:0% +the architecture of intelligence so I'm + + + align:start position:0% +the architecture of intelligence so I'm +going to take five minutes and tell you + + align:start position:0% +going to take five minutes and tell you + + + align:start position:0% +going to take five minutes and tell you +about it this work is primarily the work + + align:start position:0% +about it this work is primarily the work + + + align:start position:0% +about it this work is primarily the work +of John Duncan in England and he's been + + align:start position:0% +of John Duncan in England and he's been + + + align:start position:0% +of John Duncan in England and he's been +pointing out for about 15 years that + + align:start position:0% +pointing out for about 15 years that + + + align:start position:0% +pointing out for about 15 years that +there are regions in the frontal lobe + + align:start position:0% +there are regions in the frontal lobe + + + align:start position:0% +there are regions in the frontal lobe +shown here that are engaged in pretty + + align:start position:0% +shown here that are engaged in pretty + + + align:start position:0% +shown here that are engaged in pretty +much any difficult tasks you do anytime + + align:start position:0% +much any difficult tasks you do anytime + + + align:start position:0% +much any difficult tasks you do anytime +you increase the difficulty of a task + + align:start position:0% +you increase the difficulty of a task + + + align:start position:0% +you increase the difficulty of a task +whether it's perceptual or high-level + + align:start position:0% +whether it's perceptual or high-level + + + align:start position:0% +whether it's perceptual or high-level +cognitive those regions turn on + + align:start position:0% +cognitive those regions turn on + + + align:start position:0% +cognitive those regions turn on +differentially and so that's why he + + align:start position:0% +differentially and so that's why he + + + align:start position:0% +differentially and so that's why he +calls a multiple demand they respond to + + align:start position:0% +calls a multiple demand they respond to + + + align:start position:0% +calls a multiple demand they respond to +multiple different kinds of demand and + + align:start position:0% +multiple different kinds of demand and + + + align:start position:0% +multiple different kinds of demand and +so right Duncan argues that these + + align:start position:0% +so right Duncan argues that these + + + align:start position:0% +so right Duncan argues that these +regions are related to fluid + + align:start position:0% +regions are related to fluid + + + align:start position:0% +regions are related to fluid +intelligence + + align:start position:0% +intelligence + + + align:start position:0% +intelligence +so remember Spearman who I started with + + align:start position:0% +so remember Spearman who I started with + + + align:start position:0% +so remember Spearman who I started with +who talks about the the general factor + + align:start position:0% +who talks about the the general factor + + + align:start position:0% +who talks about the the general factor +gee well Duncan thinks that basically + + align:start position:0% +gee well Duncan thinks that basically + + + align:start position:0% +gee well Duncan thinks that basically +this is the seat of + + align:start position:0% +this is the seat of + + + align:start position:0% +this is the seat of +these regions here to oversimplify his + + align:start position:0% +these regions here to oversimplify his + + + align:start position:0% +these regions here to oversimplify his +argument evidence for that and one is + + align:start position:0% +argument evidence for that and one is + + + align:start position:0% +argument evidence for that and one is +well they're strongly activated when you + + align:start position:0% +well they're strongly activated when you + + + align:start position:0% +well they're strongly activated when you +do classic G loading tasks that's not + + align:start position:0% +do classic G loading tasks that's not + + + align:start position:0% +do classic G loading tasks that's not +that surprising they're activated in all + + align:start position:0% +that surprising they're activated in all + + + align:start position:0% +that surprising they're activated in all +different kinds of tasks more + + align:start position:0% +different kinds of tasks more + + + align:start position:0% +different kinds of tasks more +interestingly he did a large patient + + align:start position:0% +interestingly he did a large patient + + + align:start position:0% +interestingly he did a large patient +study where they found a eighty or so + + align:start position:0% +study where they found a eighty or so + + + align:start position:0% +study where they found a eighty or so +patients in their neuro psych patients + + align:start position:0% +patients in their neuro psych patients + + + align:start position:0% +patients in their neuro psych patients +in their patient database and they + + align:start position:0% +in their patient database and they + + + align:start position:0% +in their patient database and they +identified the Lok locus of the brain + + align:start position:0% +identified the Lok locus of the brain + + + align:start position:0% +identified the Lok locus of the brain +damaged in each of those patients and + + align:start position:0% +damaged in each of those patients and + + + align:start position:0% +damaged in each of those patients and +what they did was they measured post + + align:start position:0% +what they did was they measured post + + + align:start position:0% +what they did was they measured post +injury IQ they estimated from a variety + + align:start position:0% +injury IQ they estimated from a variety + + + align:start position:0% +injury IQ they estimated from a variety +of sources pre-injury IQ and they asked + + align:start position:0% +of sources pre-injury IQ and they asked + + + align:start position:0% +of sources pre-injury IQ and they asked +how much does your IQ go down after + + align:start position:0% +how much does your IQ go down after + + + align:start position:0% +how much does your IQ go down after +brain damage as a function of one the + + align:start position:0% +brain damage as a function of one the + + + align:start position:0% +brain damage as a function of one the +volume of tissue you lost in brain + + align:start position:0% +volume of tissue you lost in brain + + + align:start position:0% +volume of tissue you lost in brain +damage into the locus of tissue okay and + + align:start position:0% +damage into the locus of tissue okay and + + + align:start position:0% +damage into the locus of tissue okay and +basically what he finds is if you lose + + align:start position:0% +basically what he finds is if you lose + + + align:start position:0% +basically what he finds is if you lose +tissue in these regions your IQ goes + + align:start position:0% +tissue in these regions your IQ goes + + + align:start position:0% +tissue in these regions your IQ goes +down if you lose tissue elsewhere you + + align:start position:0% +down if you lose tissue elsewhere you + + + align:start position:0% +down if you lose tissue elsewhere you +may become paralyzed or aphasic or + + align:start position:0% +may become paralyzed or aphasic or + + + align:start position:0% +may become paralyzed or aphasic or +prosopagnosia + + align:start position:0% +prosopagnosia + + + align:start position:0% +prosopagnosia +you don't lose your your IQ does not go + + align:start position:0% +you don't lose your your IQ does not go + + + align:start position:0% +you don't lose your your IQ does not go +down okay in fact he made a kind of + + align:start position:0% +down okay in fact he made a kind of + + + align:start position:0% +down okay in fact he made a kind of +ghoulish calculation that you lose six + + align:start position:0% +ghoulish calculation that you lose six + + + align:start position:0% +ghoulish calculation that you lose six +and a half IQ points for every ten cubic + + align:start position:0% +and a half IQ points for every ten cubic + + + align:start position:0% +and a half IQ points for every ten cubic +centimeters of this region of cortex and + + align:start position:0% +centimeters of this region of cortex and + + + align:start position:0% +centimeters of this region of cortex and +almost nothing for for the rest of the + + align:start position:0% +almost nothing for for the rest of the + + + align:start position:0% +almost nothing for for the rest of the +brain so you know this is kind of crude + + align:start position:0% +brain so you know this is kind of crude + + + align:start position:0% +brain so you know this is kind of crude +it's you know it's very imperfect what + + align:start position:0% +it's you know it's very imperfect what + + + align:start position:0% +it's you know it's very imperfect what +you can get from patient study but I + + align:start position:0% +you can get from patient study but I + + + align:start position:0% +you can get from patient study but I +think it's intriguing and so his + + align:start position:0% +think it's intriguing and so his + + + align:start position:0% +think it's intriguing and so his +suggestion is that in addition to these + + align:start position:0% +suggestion is that in addition to these + + + align:start position:0% +suggestion is that in addition to these +highly specialized cortical regions that + + align:start position:0% +highly specialized cortical regions that + + + align:start position:0% +highly specialized cortical regions that +we use for these these particular + + align:start position:0% +we use for these these particular + + + align:start position:0% +we use for these these particular +important tasks we also have this kind + + align:start position:0% +important tasks we also have this kind + + + align:start position:0% +important tasks we also have this kind +of general-purpose machinery that makes + + align:start position:0% +of general-purpose machinery that makes + + + align:start position:0% +of general-purpose machinery that makes +us generically smart and I'm going to + + align:start position:0% +us generically smart and I'm going to + + + align:start position:0% +us generically smart and I'm going to +skip our own we've tested this more + + align:start position:0% +skip our own we've tested this more + + + align:start position:0% +skip our own we've tested this more +seriously he group analyses which I + + align:start position:0% +seriously he group analyses which I + + + align:start position:0% +seriously he group analyses which I +don't like we did it in collaboration + + align:start position:0% +don't like we did it in collaboration + + + align:start position:0% +don't like we did it in collaboration +with him with individual subject + + align:start position:0% +with him with individual subject + + + align:start position:0% +with him with individual subject +analyses the most precise measurements + + align:start position:0% +analyses the most precise measurements + + + align:start position:0% +analyses the most precise measurements +we could make and boy is he right I mean + + align:start position:0% +we could make and boy is he right I mean + + + align:start position:0% +we could make and boy is he right I mean +these even to the voxel you can find + + align:start position:0% +these even to the voxel you can find + + + align:start position:0% +these even to the voxel you can find +that these regions are engaged in seven + + align:start position:0% +that these regions are engaged in seven + + + align:start position:0% +that these regions are engaged in seven +or eight very very different kinds of + + align:start position:0% +or eight very very different kinds of + + + align:start position:0% +or eight very very different kinds of +cognitive demand all activate the same + + align:start position:0% +cognitive demand all activate the same + + + align:start position:0% +cognitive demand all activate the same +voxel differentially so the basic story + + align:start position:0% +voxel differentially so the basic story + + + align:start position:0% +voxel differentially so the basic story +I'm putting forth here without the whole + + align:start position:0% +I'm putting forth here without the whole + + + align:start position:0% +I'm putting forth here without the whole +second half of my talk I'm sorry about + + align:start position:0% +second half of my talk I'm sorry about + + + align:start position:0% +second half of my talk I'm sorry about +that is that + + align:start position:0% +that is that + + + align:start position:0% +that is that +is that the macroscale the architecture + + align:start position:0% +is that the macroscale the architecture + + + align:start position:0% +is that the macroscale the architecture +of human intelligence is that we have + + align:start position:0% +of human intelligence is that we have + + + align:start position:0% +of human intelligence is that we have +these special-purpose bits for a small + + align:start position:0% +these special-purpose bits for a small + + + align:start position:0% +these special-purpose bits for a small +issue of important mental functions not + + align:start position:0% +issue of important mental functions not + + + align:start position:0% +issue of important mental functions not +all of them innate maybe some of them in + + align:start position:0% +all of them innate maybe some of them in + + + align:start position:0% +all of them innate maybe some of them in +addition we have some general-purpose + + align:start position:0% +addition we have some general-purpose + + + align:start position:0% +addition we have some general-purpose +machinery there's loes work that we + + align:start position:0% +machinery there's loes work that we + + + align:start position:0% +machinery there's loes work that we +don't know from the precise computations + + align:start position:0% +don't know from the precise computations + + + align:start position:0% +don't know from the precise computations +that go on in these things to their + + align:start position:0% +that go on in these things to their + + + align:start position:0% +that go on in these things to their +connectivity to they you know the actual + + align:start position:0% +connectivity to they you know the actual + + + align:start position:0% +connectivity to they you know the actual +precise representations that you can see + + align:start position:0% +precise representations that you can see + + + align:start position:0% +precise representations that you can see +with the neural code if you could + + align:start position:0% +with the neural code if you could + + + align:start position:0% +with the neural code if you could +measure it which we can't in humans to + + align:start position:0% +measure it which we can't in humans to + + + align:start position:0% +measure it which we can't in humans to +the timing of these interactions which + + align:start position:0% +the timing of these interactions which + + + align:start position:0% +the timing of these interactions which +of them are uniquely human which of them + + align:start position:0% +of them are uniquely human which of them + + + align:start position:0% +of them are uniquely human which of them +are also present in monkeys and I don't + + align:start position:0% +are also present in monkeys and I don't + + + align:start position:0% +are also present in monkeys and I don't +have time to go find a slide but one of + + align:start position:0% +have time to go find a slide but one of + + + align:start position:0% +have time to go find a slide but one of +the things we've been doing recently is + + align:start position:0% +the things we've been doing recently is + + + align:start position:0% +the things we've been doing recently is +looking in the ventral visual pathway at + + align:start position:0% +looking in the ventral visual pathway at + + + align:start position:0% +looking in the ventral visual pathway at +the organization of face place and color + + align:start position:0% +the organization of face place and color + + + align:start position:0% +the organization of face place and color +selectivity and what we see is that as + + align:start position:0% +selectivity and what we see is that as + + + align:start position:0% +selectivity and what we see is that as +we as me and bevel Conway and Rosa Rosa + + align:start position:0% +we as me and bevel Conway and Rosa Rosa + + + align:start position:0% +we as me and bevel Conway and Rosa Rosa +later Sousa bevel and Rosa had + + align:start position:0% +later Sousa bevel and Rosa had + + + align:start position:0% +later Sousa bevel and Rosa had +previously shown that on the lateral + + align:start position:0% +previously shown that on the lateral + + + align:start position:0% +previously shown that on the lateral +surface in the monkey you have three + + align:start position:0% +surface in the monkey you have three + + + align:start position:0% +surface in the monkey you have three +bands of cell activity so it goes face + + align:start position:0% +bands of cell activity so it goes face + + + align:start position:0% +bands of cell activity so it goes face +selectivity color selectivity play + + align:start position:0% +selectivity color selectivity play + + + align:start position:0% +selectivity color selectivity play +selectivity and three bands on the side + + align:start position:0% +selectivity and three bands on the side + + + align:start position:0% +selectivity and three bands on the side +of the temporal lobe in monkeys we find + + align:start position:0% +of the temporal lobe in monkeys we find + + + align:start position:0% +of the temporal lobe in monkeys we find +is in humans you have exactly the same + + align:start position:0% +is in humans you have exactly the same + + + align:start position:0% +is in humans you have exactly the same +organization in the same order but it's + + align:start position:0% +organization in the same order but it's + + + align:start position:0% +organization in the same order but it's +rolled around on the ventral surface of + + align:start position:0% +rolled around on the ventral surface of + + + align:start position:0% +rolled around on the ventral surface of +the brain in the same order face color + + align:start position:0% +the brain in the same order face color + + + align:start position:0% +the brain in the same order face color +place on the bottom of the brain so we + + align:start position:0% +place on the bottom of the brain so we + + + align:start position:0% +place on the bottom of the brain so we +think that whole broad region is + + align:start position:0% +think that whole broad region is + + + align:start position:0% +think that whole broad region is +homologous between monkeys and humans it + + align:start position:0% +homologous between monkeys and humans it + + + align:start position:0% +homologous between monkeys and humans it +just rolled around on the bottom maybe + + align:start position:0% +just rolled around on the bottom maybe + + + align:start position:0% +just rolled around on the bottom maybe +it got pushed over something and that's + + align:start position:0% +it got pushed over something and that's + + + align:start position:0% +it got pushed over something and that's +not exactly a novel argument actually + + align:start position:0% +not exactly a novel argument actually + + + align:start position:0% +not exactly a novel argument actually +even Rick wrote a paper suggesting this + + align:start position:0% +even Rick wrote a paper suggesting this + + + align:start position:0% +even Rick wrote a paper suggesting this +a while back and I think we're starting + + align:start position:0% +a while back and I think we're starting + + + align:start position:0% +a while back and I think we're starting +to see those homologies and the reason + + align:start position:0% +to see those homologies and the reason + + + align:start position:0% +to see those homologies and the reason +that's important is that it means that + + align:start position:0% +that's important is that it means that + + + align:start position:0% +that's important is that it means that +all these questions we desperately want + + align:start position:0% +all these questions we desperately want + + + align:start position:0% +all these questions we desperately want +to answer about the you know causal + + align:start position:0% +to answer about the you know causal + + + align:start position:0% +to answer about the you know causal +world connectivity population codes + + align:start position:0% +world connectivity population codes + + + align:start position:0% +world connectivity population codes +interactions between regions development + + align:start position:0% +interactions between regions development + + + align:start position:0% +interactions between regions development +all of that that we can't answer very + + align:start position:0% +all of that that we can't answer very + + + align:start position:0% +all of that that we can't answer very +well in humans Fenric can answer in + + align:start position:0% +well in humans Fenric can answer in + + + align:start position:0% +well in humans Fenric can answer in +monkeys and after a break he will tell + + align:start position:0% +monkeys and after a break he will tell + + + align:start position:0% +monkeys and after a break he will tell +you about all of that right + + align:start position:0% +you about all of that right + + + align:start position:0% +you about all of that right +you + + align:start position:0% +you + + + align:start position:0% +you +[Applause] + + align:start position:0% + + + + align:start position:0% + +you \ No newline at end of file diff --git a/3RGYj06NSTI.txt b/3RGYj06NSTI.txt new file mode 100644 index 0000000000000000000000000000000000000000..b609135220e043fcea40a4e3d87db9940946f077 --- /dev/null +++ b/3RGYj06NSTI.txt @@ -0,0 +1,5427 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license + + align:start position:0% +a Creative Commons license + + + align:start position:0% +a Creative Commons license +your support will help MIT + + align:start position:0% +your support will help MIT + + + align:start position:0% +your support will help MIT +OpenCourseWare continue to offer high + + align:start position:0% +OpenCourseWare continue to offer high + + + align:start position:0% +OpenCourseWare continue to offer high +quality educational resources for free + + align:start position:0% +quality educational resources for free + + + align:start position:0% +quality educational resources for free +to make a donation or view additional + + align:start position:0% +to make a donation or view additional + + + align:start position:0% +to make a donation or view additional +materials from hundreds of MIT courses + + align:start position:0% +materials from hundreds of MIT courses + + + align:start position:0% +materials from hundreds of MIT courses +visit MIT opencourseware at ocw.mit.edu + + align:start position:0% + + + + align:start position:0% + +last lecture I did a fairly standard + + align:start position:0% +last lecture I did a fairly standard + + + align:start position:0% +last lecture I did a fairly standard +treatment of the harmonic oscillator + + align:start position:0% +treatment of the harmonic oscillator + + + align:start position:0% +treatment of the harmonic oscillator +which is not supposed to make you + + align:start position:0% +which is not supposed to make you + + + align:start position:0% +which is not supposed to make you +excited but just to see that you can do + + align:start position:0% +excited but just to see that you can do + + + align:start position:0% +excited but just to see that you can do +this and the the the path to the + + align:start position:0% +this and the the the path to the + + + align:start position:0% +this and the the the path to the +solution was to define dimensionless + + align:start position:0% +solution was to define dimensionless + + + align:start position:0% +solution was to define dimensionless +position coordinate and then you get a + + align:start position:0% +position coordinate and then you get a + + + align:start position:0% +position coordinate and then you get a +dimensionless Schrodinger equation and + + align:start position:0% +dimensionless Schrodinger equation and + + + align:start position:0% +dimensionless Schrodinger equation and +the solution of that involves two steps + + align:start position:0% +the solution of that involves two steps + + + align:start position:0% +the solution of that involves two steps +one is to insist that the function there + + align:start position:0% +one is to insist that the function there + + + align:start position:0% +one is to insist that the function there +was solutions to the this earlier + + align:start position:0% +was solutions to the this earlier + + + align:start position:0% +was solutions to the this earlier +equation have an exponentially damped + + align:start position:0% +equation have an exponentially damped + + + align:start position:0% +equation have an exponentially damped +form and then the Schrodinger equation + + align:start position:0% +form and then the Schrodinger equation + + + align:start position:0% +form and then the Schrodinger equation +is transformed into a new equation + + align:start position:0% +is transformed into a new equation + + + align:start position:0% +is transformed into a new equation +called the Hermit equation and you + + align:start position:0% +called the Hermit equation and you + + + align:start position:0% +called the Hermit equation and you +shouldn't get all excited about that the + + align:start position:0% +shouldn't get all excited about that the + + + align:start position:0% +shouldn't get all excited about that the +mathematicians take care of it and and + + align:start position:0% +mathematicians take care of it and and + + + align:start position:0% +mathematicians take care of it and and +so the solutions to this Hermit + + align:start position:0% +so the solutions to this Hermit + + + align:start position:0% +so the solutions to this Hermit +differential equation gives you a set of + + align:start position:0% +differential equation gives you a set of + + + align:start position:0% +differential equation gives you a set of +orthogonal and normalized wave functions + + align:start position:0% +orthogonal and normalized wave functions + + + align:start position:0% +orthogonal and normalized wave functions +they give you the energy levels + + align:start position:0% +they give you the energy levels + + + align:start position:0% +they give you the energy levels +expressed as a quantum number plus 1/2 + + align:start position:0% +expressed as a quantum number plus 1/2 + + + align:start position:0% +expressed as a quantum number plus 1/2 +times constant the energy levels the + + align:start position:0% +times constant the energy levels the + + + align:start position:0% +times constant the energy levels the +with the quantum number V are even or + + align:start position:0% +with the quantum number V are even or + + + align:start position:0% +with the quantum number V are even or +odd and V and they're even or odd in + + align:start position:0% +odd and V and they're even or odd in + + + align:start position:0% +odd and V and they're even or odd in +sigh the evens v and corresponds to even + + align:start position:0% +sigh the evens v and corresponds to even + + + align:start position:0% +sigh the evens v and corresponds to even +sy v is the number of internal nodes and + + align:start position:0% +sy v is the number of internal nodes and + + + align:start position:0% +sy v is the number of internal nodes and +there are all sorts of things you can do + + align:start position:0% +there are all sorts of things you can do + + + align:start position:0% +there are all sorts of things you can do +to say well I expect if I know how to do + + align:start position:0% +to say well I expect if I know how to do + + + align:start position:0% +to say well I expect if I know how to do +certain things in classical mechanics + + align:start position:0% +certain things in classical mechanics + + + align:start position:0% +certain things in classical mechanics +they're going to come out pretty much + + align:start position:0% +they're going to come out pretty much + + + align:start position:0% +they're going to come out pretty much +the same way in quantum mechanics so + + align:start position:0% +the same way in quantum mechanics so + + + align:start position:0% +the same way in quantum mechanics so +that's the standard structure but more + + align:start position:0% +that's the standard structure but more + + + align:start position:0% +that's the standard structure but more +importantly I want you to have in your + + align:start position:0% +importantly I want you to have in your + + + align:start position:0% +importantly I want you to have in your +head the pictures of the wave functions + + align:start position:0% +head the pictures of the wave functions + + + align:start position:0% +head the pictures of the wave functions +the idea that + + align:start position:0% +the idea that + + + align:start position:0% +the idea that +is a zero-point energy and that that + + align:start position:0% +is a zero-point energy and that that + + + align:start position:0% +is a zero-point energy and that that +there's a reason for that that the wave + + align:start position:0% +there's a reason for that that the wave + + + align:start position:0% +there's a reason for that that the wave +functions have tails extending out into + + align:start position:0% +functions have tails extending out into + + + align:start position:0% +functions have tails extending out into +the non-classical or the four + + align:start position:0% +the non-classical or the four + + + align:start position:0% +the non-classical or the four +classically forbidden region and this + + align:start position:0% +classically forbidden region and this + + + align:start position:0% +classically forbidden region and this +turns out to be the beginning of + + align:start position:0% +turns out to be the beginning of + + + align:start position:0% +turns out to be the beginning of +tunneling you'll you'll be looking at + + align:start position:0% +tunneling you'll you'll be looking at + + + align:start position:0% +tunneling you'll you'll be looking at +tunneling more more specifically we also + + align:start position:0% +tunneling more more specifically we also + + + align:start position:0% +tunneling more more specifically we also +what I also want you to know how the + + align:start position:0% +what I also want you to know how the + + + align:start position:0% +what I also want you to know how the +spacing of nodes is and that involves + + align:start position:0% +spacing of nodes is and that involves + + + align:start position:0% +spacing of nodes is and that involves +generalization of the Dubrow idea that + + align:start position:0% +generalization of the Dubrow idea that + + + align:start position:0% +generalization of the Dubrow idea that +the wave length is H over P but if the + + align:start position:0% +the wave length is H over P but if the + + + align:start position:0% +the wave length is H over P but if the +potential is not constant then P is a + + align:start position:0% +potential is not constant then P is a + + + align:start position:0% +potential is not constant then P is a +function of X this is not the classical + + align:start position:0% +function of X this is not the classical + + + align:start position:0% +function of X this is not the classical +the quantum mechanical operator this is + + align:start position:0% +the quantum mechanical operator this is + + + align:start position:0% +the quantum mechanical operator this is +a function which provides you with a lot + + align:start position:0% +a function which provides you with a lot + + + align:start position:0% +a function which provides you with a lot +of inter + + align:start position:0% +of inter + + + align:start position:0% +of inter +intuition and then see if you know where + + align:start position:0% +intuition and then see if you know where + + + align:start position:0% +intuition and then see if you know where +the node spacings are and you know the + + align:start position:0% +the node spacings are and you know the + + + align:start position:0% +the node spacings are and you know the +anvil or the shape of the envelope you + + align:start position:0% +anvil or the shape of the envelope you + + + align:start position:0% +anvil or the shape of the envelope you +have basically everything you need to + + align:start position:0% +have basically everything you need to + + + align:start position:0% +have basically everything you need to +have a classical sense of what's going + + align:start position:0% +have a classical sense of what's going + + + align:start position:0% +have a classical sense of what's going +on and then I guess it's mostly hidden I + + align:start position:0% +on and then I guess it's mostly hidden I + + + align:start position:0% +on and then I guess it's mostly hidden I +did a little bit of semi-classical + + align:start position:0% +did a little bit of semi-classical + + + align:start position:0% +did a little bit of semi-classical +theory and I showed that if you + + align:start position:0% +theory and I showed that if you + + + align:start position:0% +theory and I showed that if you +integrate from the left turning point to + + align:start position:0% +integrate from the left turning point to + + + align:start position:0% +integrate from the left turning point to +the right turning point and a given + + align:start position:0% +the right turning point and a given + + + align:start position:0% +the right turning point and a given +energy of this momentum function you get + + align:start position:0% +energy of this momentum function you get + + + align:start position:0% +energy of this momentum function you get +h over two times the number of nodes and + + align:start position:0% +h over two times the number of nodes and + + + align:start position:0% +h over two times the number of nodes and +this is the semi-classical quantization + + align:start position:0% +this is the semi-classical quantization + + + align:start position:0% +this is the semi-classical quantization +it's incredibly important and it's it's + + align:start position:0% +it's incredibly important and it's it's + + + align:start position:0% +it's incredibly important and it's it's +useful either as an exact or an + + align:start position:0% +useful either as an exact or an + + + align:start position:0% +useful either as an exact or an +approximate result for all + + align:start position:0% +approximate result for all + + + align:start position:0% +approximate result for all +one-dimensional problems and so it tells + + align:start position:0% +one-dimensional problems and so it tells + + + align:start position:0% +one-dimensional problems and so it tells +you how to how to begin now before I + + align:start position:0% +you how to how to begin now before I + + + align:start position:0% +you how to how to begin now before I +start talking about what we're gonna do + + align:start position:0% +start talking about what we're gonna do + + + align:start position:0% +start talking about what we're gonna do +today + + align:start position:0% +today + + + align:start position:0% +today +I want to stress where we're going so + + align:start position:0% +I want to stress where we're going so + + + align:start position:0% +I want to stress where we're going so +we're going to be looking at some + + align:start position:0% +we're going to be looking at some + + + align:start position:0% +we're going to be looking at some +exactly solve problems + + align:start position:0% + + + + align:start position:0% + +and so we have the particle a box there + + align:start position:0% +and so we have the particle a box there + + + align:start position:0% +and so we have the particle a box there +not much oscillator hydrogen and yet to + + align:start position:0% +not much oscillator hydrogen and yet to + + + align:start position:0% +not much oscillator hydrogen and yet to +come and the rigid rotor now all of + + align:start position:0% +come and the rigid rotor now all of + + + align:start position:0% +come and the rigid rotor now all of +these problems have an infinite number + + align:start position:0% +these problems have an infinite number + + + align:start position:0% +these problems have an infinite number +of eigen functions an infinite number of + + align:start position:0% +of eigen functions an infinite number of + + + align:start position:0% +of eigen functions an infinite number of +energy levels and that's intimidating + + align:start position:0% +energy levels and that's intimidating + + + align:start position:0% +energy levels and that's intimidating +but it's true now this these infinite + + align:start position:0% +but it's true now this these infinite + + + align:start position:0% +but it's true now this these infinite +number of functions are explicit + + align:start position:0% +number of functions are explicit + + + align:start position:0% +number of functions are explicit +functions of the quantum number and so + + align:start position:0% +functions of the quantum number and so + + + align:start position:0% +functions of the quantum number and so +we have an infinite number but in order + + align:start position:0% +we have an infinite number but in order + + + align:start position:0% +we have an infinite number but in order +to describe systems we're going to be + + align:start position:0% +to describe systems we're going to be + + + align:start position:0% +to describe systems we're going to be +calculating integrals we're going to be + + align:start position:0% +calculating integrals we're going to be + + + align:start position:0% +calculating integrals we're going to be +calculating a lot of integrals between + + align:start position:0% +calculating a lot of integrals between + + + align:start position:0% +calculating a lot of integrals between +these infinite number of functions so we + + align:start position:0% +these infinite number of functions so we + + + align:start position:0% +these infinite number of functions so we +have an infinity squared of integrals + + align:start position:0% +have an infinity squared of integrals + + + align:start position:0% +have an infinity squared of integrals +well I shouldn't scare you because well + + align:start position:0% +well I shouldn't scare you because well + + + align:start position:0% +well I shouldn't scare you because well +you but I'm going to show you is that + + align:start position:0% +you but I'm going to show you is that + + + align:start position:0% +you but I'm going to show you is that +all of the integrals that we are going + + align:start position:0% +all of the integrals that we are going + + + align:start position:0% +all of the integrals that we are going +to encounter our explicit functions of + + align:start position:0% +to encounter our explicit functions of + + + align:start position:0% +to encounter our explicit functions of +the quantum numbers and they have rather + + align:start position:0% +the quantum numbers and they have rather + + + align:start position:0% +the quantum numbers and they have rather +relatively selection rules in other + + align:start position:0% +relatively selection rules in other + + + align:start position:0% +relatively selection rules in other +words which integrals are nonzero based + + align:start position:0% +words which integrals are nonzero based + + + align:start position:0% +words which integrals are nonzero based +on the difference in quantum numbers + + align:start position:0% +on the difference in quantum numbers + + + align:start position:0% +on the difference in quantum numbers +between the left-hand side and the + + align:start position:0% +between the left-hand side and the + + + align:start position:0% +between the left-hand side and the +right-hand side so we're collecting + + align:start position:0% +right-hand side so we're collecting + + + align:start position:0% +right-hand side so we're collecting +these things in order to calculate a + + align:start position:0% +these things in order to calculate a + + + align:start position:0% +these things in order to calculate a +whole bunch of stuff and I told you that + + align:start position:0% +whole bunch of stuff and I told you that + + + align:start position:0% +whole bunch of stuff and I told you that +this of course for use rather than + + align:start position:0% +this of course for use rather than + + + align:start position:0% +this of course for use rather than +philosophy or history and so if you + + align:start position:0% +philosophy or history and so if you + + + align:start position:0% +philosophy or history and so if you +encounter any quantum mechanical problem + + align:start position:0% +encounter any quantum mechanical problem + + + align:start position:0% +encounter any quantum mechanical problem +you'd like to be able to describe what + + align:start position:0% +you'd like to be able to describe what + + + align:start position:0% +you'd like to be able to describe what +you could observe with it and so if + + align:start position:0% +you could observe with it and so if + + + align:start position:0% +you could observe with it and so if +you're armed with the infinite number of + + align:start position:0% +you're armed with the infinite number of + + + align:start position:0% +you're armed with the infinite number of +energy levels and eigen solutions for + + align:start position:0% +energy levels and eigen solutions for + + + align:start position:0% +energy levels and eigen solutions for +our problem you can calculate any + + align:start position:0% +our problem you can calculate any + + + align:start position:0% +our problem you can calculate any +property + + align:start position:0% +property + + + align:start position:0% +property +so you define some property you're + + align:start position:0% +so you define some property you're + + + align:start position:0% +so you define some property you're +interested in there is a quantum + + align:start position:0% +interested in there is a quantum + + + align:start position:0% +interested in there is a quantum +mechanical operator that corresponds to + + align:start position:0% +mechanical operator that corresponds to + + + align:start position:0% +mechanical operator that corresponds to +that property and in order to be able to + + align:start position:0% +that property and in order to be able to + + + align:start position:0% +that property and in order to be able to +describe the observations of that + + align:start position:0% +describe the observations of that + + + align:start position:0% +describe the observations of that +property you need to calculate integrals + + align:start position:0% +property you need to calculate integrals + + + align:start position:0% +property you need to calculate integrals +of that operator well la-dee-da that's + + align:start position:0% +of that operator well la-dee-da that's + + + align:start position:0% +of that operator well la-dee-da that's +that should be intimidating but it's not + + align:start position:0% +that should be intimidating but it's not + + + align:start position:0% +that should be intimidating but it's not +because almost all of these integrals + + align:start position:0% +because almost all of these integrals + + + align:start position:0% +because almost all of these integrals +can be expressed as a simple constant + + align:start position:0% +can be expressed as a simple constant + + + align:start position:0% +can be expressed as a simple constant +times a function of the quantum numbers + + align:start position:0% +times a function of the quantum numbers + + + align:start position:0% +times a function of the quantum numbers +or the difference of quantum numbers and + + align:start position:0% +or the difference of quantum numbers and + + + align:start position:0% +or the difference of quantum numbers and +that's that that's a fantastic thing we + + align:start position:0% +that's that that's a fantastic thing we + + + align:start position:0% +that's that that's a fantastic thing we +can also so we have any operator we have + + align:start position:0% +can also so we have any operator we have + + + align:start position:0% +can also so we have any operator we have +supposed the Hamiltonian is an exactly + + align:start position:0% +supposed the Hamiltonian is an exactly + + + align:start position:0% +supposed the Hamiltonian is an exactly +solve problem plus something else which + + align:start position:0% +solve problem plus something else which + + + align:start position:0% +solve problem plus something else which +we'll call h1 and this is complicated + + align:start position:0% +we'll call h1 and this is complicated + + + align:start position:0% +we'll call h1 and this is complicated +this is a complexity in the or it's the + + align:start position:0% +this is a complexity in the or it's the + + + align:start position:0% +this is a complexity in the or it's the +reality in the problem and in order to + + align:start position:0% +reality in the problem and in order to + + + align:start position:0% +reality in the problem and in order to +to deal with this again you're going to + + align:start position:0% +to deal with this again you're going to + + + align:start position:0% +to deal with this again you're going to +need to calculate integrals of this + + align:start position:0% +need to calculate integrals of this + + + align:start position:0% +need to calculate integrals of this +operator and the last thing that's + + align:start position:0% +operator and the last thing that's + + + align:start position:0% +operator and the last thing that's +really great to be exciting is once we + + align:start position:0% +really great to be exciting is once we + + + align:start position:0% +really great to be exciting is once we +do the time and once we look at the + + align:start position:0% +do the time and once we look at the + + + align:start position:0% +do the time and once we look at the +time-dependent schrodinger equation + + align:start position:0% +time-dependent schrodinger equation + + + align:start position:0% +time-dependent schrodinger equation +we're going to get wave packets and + + align:start position:0% +we're going to get wave packets and + + + align:start position:0% +we're going to get wave packets and +these are functions of position and time + + align:start position:0% +these are functions of position and time + + + align:start position:0% +these are functions of position and time +and these wave packets are classical + + align:start position:0% +and these wave packets are classical + + + align:start position:0% +and these wave packets are classical +like localized objects that move + + align:start position:0% +like localized objects that move + + + align:start position:0% +like localized objects that move +following the Newton's equations of + + align:start position:0% +following the Newton's equations of + + + align:start position:0% +following the Newton's equations of +motion for the center of the wave packet + + align:start position:0% +motion for the center of the wave packet + + + align:start position:0% +motion for the center of the wave packet +and again there are a whole bunch of + + align:start position:0% +and again there are a whole bunch of + + + align:start position:0% +and again there are a whole bunch of +integrals you're going to need in order + + align:start position:0% +integrals you're going to need in order + + + align:start position:0% +integrals you're going to need in order +to do these things and so right now + + align:start position:0% +to do these things and so right now + + + align:start position:0% +to do these things and so right now +we're starting with the best problem for + + align:start position:0% +we're starting with the best problem for + + + align:start position:0% +we're starting with the best problem for +these integrals because the harmonic + + align:start position:0% +these integrals because the harmonic + + + align:start position:0% +these integrals because the harmonic +oscillator has so special properties and + + align:start position:0% +oscillator has so special properties and + + + align:start position:0% +oscillator has so special properties and +the lecture notes are incredibly tedious + + align:start position:0% +the lecture notes are incredibly tedious + + + align:start position:0% +the lecture notes are incredibly tedious +and they're mostly proofs and I'm going + + align:start position:0% +and they're mostly proofs and I'm going + + + align:start position:0% +and they're mostly proofs and I'm going +to try to go fast over the the the + + align:start position:0% +to try to go fast over the the the + + + align:start position:0% +to try to go fast over the the the +tedious stuff and + + align:start position:0% + + + + align:start position:0% + +give you the important ideas but since + + align:start position:0% +give you the important ideas but since + + + align:start position:0% +give you the important ideas but since +there is so important logic you should + + align:start position:0% +there is so important logic you should + + + align:start position:0% +there is so important logic you should +really look at these notes okay so what + + align:start position:0% +really look at these notes okay so what + + + align:start position:0% +really look at these notes okay so what +we're going to be doing today is we + + align:start position:0% +we're going to be doing today is we + + + align:start position:0% +we're going to be doing today is we +start with the coordinate momentum + + align:start position:0% +start with the coordinate momentum + + + align:start position:0% +start with the coordinate momentum +operators we're going to get the these + + align:start position:0% +operators we're going to get the these + + + align:start position:0% +operators we're going to get the these +operators in dimensionless form and then + + align:start position:0% +operators in dimensionless form and then + + + align:start position:0% +operators in dimensionless form and then +we're going to get these a and a dagger + + align:start position:0% +we're going to get these a and a dagger + + + align:start position:0% +we're going to get these a and a dagger +guys and this so this step is + + align:start position:0% +guys and this so this step is + + + align:start position:0% +guys and this so this step is +reminiscent of what I did at the + + align:start position:0% +reminiscent of what I did at the + + + align:start position:0% +reminiscent of what I did at the +beginning of the previous lecture and + + align:start position:0% +beginning of the previous lecture and + + + align:start position:0% +beginning of the previous lecture and +then this is magic because this magic + + align:start position:0% +then this is magic because this magic + + + align:start position:0% +then this is magic because this magic +enables you to just look at integrals + + align:start position:0% +enables you to just look at integrals + + + align:start position:0% +enables you to just look at integrals +and say I know that integral is zero or + + align:start position:0% +and say I know that integral is zero or + + + align:start position:0% +and say I know that integral is zero or +I know that area was not zero and with a + + align:start position:0% +I know that area was not zero and with a + + + align:start position:0% +I know that area was not zero and with a +little bit more effort maybe something + + align:start position:0% +little bit more effort maybe something + + + align:start position:0% +little bit more effort maybe something +that you put on the back of a postage + + align:start position:0% +that you put on the back of a postage + + + align:start position:0% +that you put on the back of a postage +stamp you can evaluate that integral not + + align:start position:0% +stamp you can evaluate that integral not + + + align:start position:0% +stamp you can evaluate that integral not +by knowing integral tables but by + + align:start position:0% +by knowing integral tables but by + + + align:start position:0% +by knowing integral tables but by +knowing the properties of these simple + + align:start position:0% +knowing the properties of these simple + + + align:start position:0% +knowing the properties of these simple +little a and a dagger and that's a + + align:start position:0% +little a and a dagger and that's a + + + align:start position:0% +little a and a dagger and that's a +fantastic thing and it's so fantastic + + align:start position:0% +fantastic thing and it's so fantastic + + + align:start position:0% +fantastic thing and it's so fantastic +that this is one of the reasons why + + align:start position:0% +that this is one of the reasons why + + + align:start position:0% +that this is one of the reasons why +almost all problems in quantum mechanics + + align:start position:0% +almost all problems in quantum mechanics + + + align:start position:0% +almost all problems in quantum mechanics +start with a harmonic oscillator + + align:start position:0% +start with a harmonic oscillator + + + align:start position:0% +start with a harmonic oscillator +approximation because there is so much + + align:start position:0% +approximation because there is so much + + + align:start position:0% +approximation because there is so much +you can do with this a and a dagger + + align:start position:0% +you can do with this a and a dagger + + + align:start position:0% +you can do with this a and a dagger +formalism now at the beginning I also + + align:start position:0% +formalism now at the beginning I also + + + align:start position:0% +formalism now at the beginning I also +told you that in quantum mechanics the + + align:start position:0% +told you that in quantum mechanics the + + + align:start position:0% +told you that in quantum mechanics the +important thing that contains everything + + align:start position:0% +important thing that contains everything + + + align:start position:0% +important thing that contains everything +we're allowed to know about a system is + + align:start position:0% +we're allowed to know about a system is + + + align:start position:0% +we're allowed to know about a system is +the wave function but I also told you we + + align:start position:0% +the wave function but I also told you we + + + align:start position:0% +the wave function but I also told you we +can never measure the wave function we + + align:start position:0% +can never measure the wave function we + + + align:start position:0% +can never measure the wave function we +can never experimentally determine it + + align:start position:0% +can never experimentally determine it + + + align:start position:0% +can never experimentally determine it +and so we need to be able to calculate + + align:start position:0% +and so we need to be able to calculate + + + align:start position:0% +and so we need to be able to calculate +what this wave function does as far as + + align:start position:0% +what this wave function does as far as + + + align:start position:0% +what this wave function does as far as +what we can observe and these aids in a + + align:start position:0% +what we can observe and these aids in a + + + align:start position:0% +what we can observe and these aids in a +daggers are really important than being + + align:start position:0% +daggers are really important than being + + + align:start position:0% +daggers are really important than being +able to do that okay so + + align:start position:0% +able to do that okay so + + + align:start position:0% +able to do that okay so +I'm going to start with covering what I + + align:start position:0% +I'm going to start with covering what I + + + align:start position:0% +I'm going to start with covering what I +did in the notes but I'm going to jump + + align:start position:0% +did in the notes but I'm going to jump + + + align:start position:0% +did in the notes but I'm going to jump +to final results at some point governed + + align:start position:0% +to final results at some point governed + + + align:start position:0% +to final results at some point governed +by the clock and so the first thing + + align:start position:0% +by the clock and so the first thing + + + align:start position:0% +by the clock and so the first thing +we're going to do is these and so what + + align:start position:0% +we're going to do is these and so what + + + align:start position:0% +we're going to do is these and so what +we do is we define the relationship + + align:start position:0% +we do is we define the relationship + + + align:start position:0% +we do is we define the relationship +between the ordinary position coordinate + + align:start position:0% +between the ordinary position coordinate + + + align:start position:0% +between the ordinary position coordinate +and this little twiddle means it's + + align:start position:0% +and this little twiddle means it's + + + align:start position:0% +and this little twiddle means it's +dimensionless and so we can write the + + align:start position:0% +dimensionless and so we can write the + + + align:start position:0% +dimensionless and so we can write the +inverse of that and that's the one we + + align:start position:0% +inverse of that and that's the one we + + + align:start position:0% +inverse of that and that's the one we +are going to want to well actually we go + + align:start position:0% +are going to want to well actually we go + + + align:start position:0% +are going to want to well actually we go +both ways okay and we do the same thing + + align:start position:0% +both ways okay and we do the same thing + + + align:start position:0% +both ways okay and we do the same thing +for the momentum P is equal to H bar mu + + align:start position:0% +for the momentum P is equal to H bar mu + + + align:start position:0% +for the momentum P is equal to H bar mu +Omega square root P twiddle and the + + align:start position:0% +Omega square root P twiddle and the + + + align:start position:0% +Omega square root P twiddle and the +inverse finally which I don't need to + + align:start position:0% +inverse finally which I don't need to + + + align:start position:0% +inverse finally which I don't need to +write and finally we get the Hamiltonian + + align:start position:0% +write and finally we get the Hamiltonian + + + align:start position:0% +write and finally we get the Hamiltonian +which is V squared or 2 mu plus 1/2 K x + + align:start position:0% +which is V squared or 2 mu plus 1/2 K x + + + align:start position:0% +which is V squared or 2 mu plus 1/2 K x +squared and we'll put that into these + + align:start position:0% +squared and we'll put that into these + + + align:start position:0% +squared and we'll put that into these +new units so we have H bar mu Omega over + + align:start position:0% +new units so we have H bar mu Omega over + + + align:start position:0% +new units so we have H bar mu Omega over +2 mu P twiddle squared plus K over 2 now + + align:start position:0% +2 mu P twiddle squared plus K over 2 now + + + align:start position:0% +2 mu P twiddle squared plus K over 2 now +this is all very tedious but the payoff + + align:start position:0% +this is all very tedious but the payoff + + + align:start position:0% +this is all very tedious but the payoff +is very soon K over 2 times H bar Omega + + align:start position:0% +is very soon K over 2 times H bar Omega + + + align:start position:0% +is very soon K over 2 times H bar Omega +x squared + + align:start position:0% + + + + align:start position:0% + +well isn't that interesting we we can + + align:start position:0% +well isn't that interesting we we can + + + align:start position:0% +well isn't that interesting we we can +combine week we can absorb a K over mu + + align:start position:0% +combine week we can absorb a K over mu + + + align:start position:0% +combine week we can absorb a K over mu +in Omega and so we get actually a big + + align:start position:0% +in Omega and so we get actually a big + + + align:start position:0% +in Omega and so we get actually a big +simplification we get H bar Omega over 2 + + align:start position:0% +simplification we get H bar Omega over 2 + + + align:start position:0% +simplification we get H bar Omega over 2 +times P twiddle squared + x squared well + + align:start position:0% +times P twiddle squared + x squared well + + + align:start position:0% +times P twiddle squared + x squared well +that's it that looks simpler okay and so + + align:start position:0% +that's it that looks simpler okay and so + + + align:start position:0% +that's it that looks simpler okay and so +the next thing we do is it looks like a + + align:start position:0% +the next thing we do is it looks like a + + + align:start position:0% +the next thing we do is it looks like a +simple simple problem from algebra let's + + align:start position:0% +simple simple problem from algebra let's + + + align:start position:0% +simple simple problem from algebra let's +factor this now it's a little tricky + + align:start position:0% +factor this now it's a little tricky + + + align:start position:0% +factor this now it's a little tricky +because you know you know you can factor + + align:start position:0% +because you know you know you can factor + + + align:start position:0% +because you know you know you can factor +something in real terms if this is a + + align:start position:0% +something in real terms if this is a + + + align:start position:0% +something in real terms if this is a +minus sign but we are allowed to talk + + align:start position:0% +minus sign but we are allowed to talk + + + align:start position:0% +minus sign but we are allowed to talk +about complex quantities and so we can + + align:start position:0% +about complex quantities and so we can + + + align:start position:0% +about complex quantities and so we can +we can factor that and so this term the + + align:start position:0% +we can factor that and so this term the + + + align:start position:0% +we can factor that and so this term the +twiddle plus it's equal to IP little + + align:start position:0% +twiddle plus it's equal to IP little + + + align:start position:0% +twiddle plus it's equal to IP little +plus x times minus IP little plus X okay + + align:start position:0% +plus x times minus IP little plus X okay + + + align:start position:0% +plus x times minus IP little plus X okay +and you can work that out that IP times + + align:start position:0% +and you can work that out that IP times + + + align:start position:0% +and you can work that out that IP times +I minus I P is P squared and x times X + + align:start position:0% +I minus I P is P squared and x times X + + + align:start position:0% +I minus I P is P squared and x times X +is x squared and then we have these + + align:start position:0% +is x squared and then we have these + + + align:start position:0% +is x squared and then we have these +cross terms IP times X and x times minus + + align:start position:0% +cross terms IP times X and x times minus + + + align:start position:0% +cross terms IP times X and x times minus +IP looks they don't commute if this were + + align:start position:0% +IP looks they don't commute if this were + + + align:start position:0% +IP looks they don't commute if this were +algebra well they would go away but they + + align:start position:0% +algebra well they would go away but they + + + align:start position:0% +algebra well they would go away but they +don't and so what you end up getting is + + align:start position:0% + + + + align:start position:0% + +P little squared plus X twiddle squared + + align:start position:0% +P little squared plus X twiddle squared + + + align:start position:0% +P little squared plus X twiddle squared +I dimes I'm gonna stop writing the + + align:start position:0% +I dimes I'm gonna stop writing the + + + align:start position:0% +I dimes I'm gonna stop writing the +twiddle so okay so we have this I want + + align:start position:0% +twiddle so okay so we have this I want + + + align:start position:0% +twiddle so okay so we have this I want +to make sure that I haven't sabotage + + align:start position:0% +to make sure that I haven't sabotage + + + align:start position:0% +to make sure that I haven't sabotage +myself that's going to be yeah that's + + align:start position:0% +myself that's going to be yeah that's + + + align:start position:0% +myself that's going to be yeah that's +right + + align:start position:0% +right + + + align:start position:0% +right +okay so we have something here that + + align:start position:0% +okay so we have something here that + + + align:start position:0% +okay so we have something here that +isn't zero it looks like I times the + + align:start position:0% +isn't zero it looks like I times the + + + align:start position:0% +isn't zero it looks like I times the +commutator of P twiddle with x12 well we + + align:start position:0% +commutator of P twiddle with x12 well we + + + align:start position:0% +commutator of P twiddle with x12 well we +can work that out because we know the + + align:start position:0% +can work that out because we know the + + + align:start position:0% +can work that out because we know the +commutator of P ordinary with X ordinary + + align:start position:0% +commutator of P ordinary with X ordinary + + + align:start position:0% +commutator of P ordinary with X ordinary +and so I did that and so we have this + + align:start position:0% +and so I did that and so we have this + + + align:start position:0% +and so I did that and so we have this +commutator P after some algebra we get + + align:start position:0% +commutator P after some algebra we get + + + align:start position:0% +commutator P after some algebra we get ++1 a number a pure number no I want you + + align:start position:0% ++1 a number a pure number no I want you + + + align:start position:0% ++1 a number a pure number no I want you +to check my algebra so you just + + align:start position:0% +to check my algebra so you just + + + align:start position:0% +to check my algebra so you just +substitute in what this is in terms of + + align:start position:0% +substitute in what this is in terms of + + + align:start position:0% +substitute in what this is in terms of +ordinary P and the ordinary X use the + + align:start position:0% +ordinary P and the ordinary X use the + + + align:start position:0% +ordinary P and the ordinary X use the +commutator for ordinary X P which is IH + + align:start position:0% +commutator for ordinary X P which is IH + + + align:start position:0% +commutator for ordinary X P which is IH +bar and magically you get +1 so + + align:start position:0% + + + + align:start position:0% + +there's very strange and boring + + align:start position:0% +there's very strange and boring + + + align:start position:0% +there's very strange and boring +derivation says okay well it's okay and + + align:start position:0% +derivation says okay well it's okay and + + + align:start position:0% +derivation says okay well it's okay and +let's now give these two things names + + align:start position:0% +let's now give these two things names + + + align:start position:0% +let's now give these two things names +okay this guy we're going to call as a + + align:start position:0% +okay this guy we're going to call as a + + + align:start position:0% +okay this guy we're going to call as a +as a square root of two times a and this + + align:start position:0% +as a square root of two times a and this + + + align:start position:0% +as a square root of two times a and this +one is going to be the square root of + + align:start position:0% +one is going to be the square root of + + + align:start position:0% +one is going to be the square root of +two times a dagger so H is going to be H + + align:start position:0% +two times a dagger so H is going to be H + + + align:start position:0% +two times a dagger so H is going to be H +bar Omega over 2 times square root 2 a + + align:start position:0% + + + + align:start position:0% + +squared of 2 a dagger minus 1 remember + + align:start position:0% +squared of 2 a dagger minus 1 remember + + + align:start position:0% +squared of 2 a dagger minus 1 remember +when we factored it we got this extra + + align:start position:0% +when we factored it we got this extra + + + align:start position:0% +when we factored it we got this extra +term which was 1 and in order to make it + + align:start position:0% +term which was 1 and in order to make it + + + align:start position:0% +term which was 1 and in order to make it +correct we have to subtract it away ok + + align:start position:0% +correct we have to subtract it away ok + + + align:start position:0% +correct we have to subtract it away ok +and so this becomes H bar Omega Hey - + + align:start position:0% +and so this becomes H bar Omega Hey - + + + align:start position:0% +and so this becomes H bar Omega Hey - +yeah + + align:start position:0% +yeah + + + align:start position:0% +yeah +oh isn't that nice now we have the + + align:start position:0% +oh isn't that nice now we have the + + + align:start position:0% +oh isn't that nice now we have the +Hamiltonian expressed as a constant + + align:start position:0% +Hamiltonian expressed as a constant + + + align:start position:0% +Hamiltonian expressed as a constant +which we know is important because it's + + align:start position:0% +which we know is important because it's + + + align:start position:0% +which we know is important because it's +related to the energy levels and times + + align:start position:0% +related to the energy levels and times + + + align:start position:0% +related to the energy levels and times +these two little things which turn out + + align:start position:0% +these two little things which turn out + + + align:start position:0% +these two little things which turn out +to be the gift from God it's it's an + + align:start position:0% +to be the gift from God it's it's an + + + align:start position:0% +to be the gift from God it's it's an +incredible thing what these do okay so + + align:start position:0% +incredible thing what these do okay so + + + align:start position:0% +incredible thing what these do okay so +we have gone through some algebra and we + + align:start position:0% +we have gone through some algebra and we + + + align:start position:0% +we have gone through some algebra and we +know the relationship between a and the + + align:start position:0% +know the relationship between a and the + + + align:start position:0% +know the relationship between a and the +X and P twiddles + + align:start position:0% +X and P twiddles + + + align:start position:0% +X and P twiddles +and we can similarly for a dagger and we + + align:start position:0% +and we can similarly for a dagger and we + + + align:start position:0% +and we can similarly for a dagger and we +can go in the other direction and we + + align:start position:0% +can go in the other direction and we + + + align:start position:0% +can go in the other direction and we +know the commutator and now we're going + + align:start position:0% +know the commutator and now we're going + + + align:start position:0% +know the commutator and now we're going +to start doing some really + + align:start position:0% +to start doing some really + + + align:start position:0% +to start doing some really +great stuff okay well one thing we're + + align:start position:0% +great stuff okay well one thing we're + + + align:start position:0% +great stuff okay well one thing we're +going to want to know about is a hat a + + align:start position:0% +going to want to know about is a hat a + + + align:start position:0% +going to want to know about is a hat a +hat a dagger that commutator had and + + align:start position:0% +hat a dagger that commutator had and + + + align:start position:0% +hat a dagger that commutator had and +that turns out to be well I already did + + align:start position:0% +that turns out to be well I already did + + + align:start position:0% +that turns out to be well I already did +I already derived it it turns out to be + + align:start position:0% +I already derived it it turns out to be + + + align:start position:0% +I already derived it it turns out to be +plus one and as a result we can say + + align:start position:0% +plus one and as a result we can say + + + align:start position:0% +plus one and as a result we can say +things like this a a dagger + + align:start position:0% + + + + align:start position:0% + +sorry so using this trick we can show we + + align:start position:0% +sorry so using this trick we can show we + + + align:start position:0% +sorry so using this trick we can show we +can always replace something like a a + + align:start position:0% +can always replace something like a a + + + align:start position:0% +can always replace something like a a +dagger by a dagger a + this commutator + + align:start position:0% +dagger by a dagger a + this commutator + + + align:start position:0% +dagger by a dagger a + this commutator +which is one and so we have this really + + align:start position:0% +which is one and so we have this really + + + align:start position:0% +which is one and so we have this really +neat way of reversing the order of the + + align:start position:0% +neat way of reversing the order of the + + + align:start position:0% +neat way of reversing the order of the +A's and a daggers so with this we're + + align:start position:0% +A's and a daggers so with this we're + + + align:start position:0% +A's and a daggers so with this we're +going to soon discover that a operating + + align:start position:0% +going to soon discover that a operating + + + align:start position:0% +going to soon discover that a operating +on the eigen function gives square root + + align:start position:0% +on the eigen function gives square root + + + align:start position:0% +on the eigen function gives square root +of V times psy.d - 1 + a dagger + + align:start position:0% +of V times psy.d - 1 + a dagger + + + align:start position:0% +of V times psy.d - 1 + a dagger +operating on this one wave function + + align:start position:0% +operating on this one wave function + + + align:start position:0% +operating on this one wave function +gives v + 1 square by V + 1 which is the + + align:start position:0% +gives v + 1 square by V + 1 which is the + + + align:start position:0% +gives v + 1 square by V + 1 which is the +reason these things are valuable because + + align:start position:0% +reason these things are valuable because + + + align:start position:0% +reason these things are valuable because +if you have any any eigenfunction you + + align:start position:0% +if you have any any eigenfunction you + + + align:start position:0% +if you have any any eigenfunction you +can get all of the others so suppose you + + align:start position:0% +can get all of the others so suppose you + + + align:start position:0% +can get all of the others so suppose you +have the lowest eigenfunction you apply + + align:start position:0% +have the lowest eigenfunction you apply + + + align:start position:0% +have the lowest eigenfunction you apply +a dagger on it as many times as you need + + align:start position:0% +a dagger on it as many times as you need + + + align:start position:0% +a dagger on it as many times as you need +to get to say the Vieth function so you + + align:start position:0% +to get to say the Vieth function so you + + + align:start position:0% +to get to say the Vieth function so you +don't actually you're not going to be + + align:start position:0% +don't actually you're not going to be + + + align:start position:0% +don't actually you're not going to be +evaluating integrals you're be going to + + align:start position:0% +evaluating integrals you're be going to + + + align:start position:0% +evaluating integrals you're be going to +be counting A's and a daggers and + + align:start position:0% +be counting A's and a daggers and + + + align:start position:0% +be counting A's and a daggers and +permuting them around and getting ones + + align:start position:0% +permuting them around and getting ones + + + align:start position:0% +permuting them around and getting ones +and stuff like that yes I didn't what + + align:start position:0% + + + + align:start position:0% + +okay so this is to switch the order and + + align:start position:0% +okay so this is to switch the order and + + + align:start position:0% +okay so this is to switch the order and +I've done that and that then is no I + + align:start position:0% +I've done that and that then is no I + + + align:start position:0% +I've done that and that then is no I +think wait a second okay so we have a a + + align:start position:0% +think wait a second okay so we have a a + + + align:start position:0% +think wait a second okay so we have a a +dagger so that's a a a dagger minus a + + align:start position:0% +dagger so that's a a a dagger minus a + + + align:start position:0% +dagger so that's a a a dagger minus a +dagger a and that's oh yeah thank you + + align:start position:0% +dagger a and that's oh yeah thank you + + + align:start position:0% +dagger a and that's oh yeah thank you +it's very very easy to get lost and once + + align:start position:0% +it's very very easy to get lost and once + + + align:start position:0% +it's very very easy to get lost and once +you lost you can never be found because + + align:start position:0% +you lost you can never be found because + + + align:start position:0% +you lost you can never be found because +you've made a mistake that's built into + + align:start position:0% +you've made a mistake that's built into + + + align:start position:0% +you've made a mistake that's built into +your logic and you're never going to see + + align:start position:0% +your logic and you're never going to see + + + align:start position:0% +your logic and you're never going to see +it see it took me a couple of minutes to + + align:start position:0% +it see it took me a couple of minutes to + + + align:start position:0% +it see it took me a couple of minutes to +even accept that the the inside from ITA + + align:start position:0% +even accept that the the inside from ITA + + + align:start position:0% +even accept that the the inside from ITA +was sitting there calmly thinking and + + align:start position:0% +was sitting there calmly thinking and + + + align:start position:0% +was sitting there calmly thinking and +I'm trying to do several things in + + align:start position:0% +I'm trying to do several things in + + + align:start position:0% +I'm trying to do several things in +addition to think okay so we we can do + + align:start position:0% +addition to think okay so we we can do + + + align:start position:0% +addition to think okay so we we can do +things like this suppose we have sigh I + + align:start position:0% +things like this suppose we have sigh I + + + align:start position:0% +things like this suppose we have sigh I +can't use this notation yet so suppose + + align:start position:0% +can't use this notation yet so suppose + + + align:start position:0% +can't use this notation yet so suppose +we have Sai star V and we have a dagger + + align:start position:0% +we have Sai star V and we have a dagger + + + align:start position:0% +we have Sai star V and we have a dagger +a dagger a dagger high V prime DX + + align:start position:0% + + + + align:start position:0% + +these are razing operators so this is + + align:start position:0% +these are razing operators so this is + + + align:start position:0% +these are razing operators so this is +going to take V the V prime to be prime + + align:start position:0% +going to take V the V prime to be prime + + + align:start position:0% +going to take V the V prime to be prime +plus three those who that's the only + + align:start position:0% +plus three those who that's the only + + + align:start position:0% +plus three those who that's the only +integral that's 0 not 0 and we get V + + align:start position:0% +integral that's 0 not 0 and we get V + + + align:start position:0% +integral that's 0 not 0 and we get V +prime plus 1 V prime plus 2 V prime plus + + align:start position:0% +prime plus 1 V prime plus 2 V prime plus + + + align:start position:0% +prime plus 1 V prime plus 2 V prime plus +3 square root as the constants and this + + align:start position:0% +3 square root as the constants and this + + + align:start position:0% +3 square root as the constants and this +would be so that you know instead of + + align:start position:0% +would be so that you know instead of + + + align:start position:0% +would be so that you know instead of +evaluating an integral looking at what + + align:start position:0% +evaluating an integral looking at what + + + align:start position:0% +evaluating an integral looking at what +the X's and peas are we we just have a + + align:start position:0% +the X's and peas are we we just have a + + + align:start position:0% +the X's and peas are we we just have a +little game we play okay so now + + align:start position:0% + + + + align:start position:0% + +we have to prove some of the things I've + + align:start position:0% +we have to prove some of the things I've + + + align:start position:0% +we have to prove some of the things I've +said so we have eight and we're going to + + align:start position:0% +said so we have eight and we're going to + + + align:start position:0% +said so we have eight and we're going to +operate on a dagger sy V so what does + + align:start position:0% +operate on a dagger sy V so what does + + + align:start position:0% +operate on a dagger sy V so what does +the Hamiltonian do to this thing so what + + align:start position:0% +the Hamiltonian do to this thing so what + + + align:start position:0% +the Hamiltonian do to this thing so what +we're going to want to do is to the show + + align:start position:0% +we're going to want to do is to the show + + + align:start position:0% +we're going to want to do is to the show +that this thing is an eigen value eigen + + align:start position:0% +that this thing is an eigen value eigen + + + align:start position:0% +that this thing is an eigen value eigen +function V plus one and that's what + + align:start position:0% +function V plus one and that's what + + + align:start position:0% +function V plus one and that's what +we're going to get so let's just go + + align:start position:0% +we're going to get so let's just go + + + align:start position:0% +we're going to get so let's just go +through this so we have h-bar Omega a + + align:start position:0% +through this so we have h-bar Omega a + + + align:start position:0% +through this so we have h-bar Omega a +dagger A plus 1/2 times sy v so what I + + align:start position:0% +dagger A plus 1/2 times sy v so what I + + + align:start position:0% +dagger A plus 1/2 times sy v so what I +did is yeah I showed that the + + align:start position:0% +did is yeah I showed that the + + + align:start position:0% +did is yeah I showed that the +Hamiltonian oh yeah I did right here the + + align:start position:0% +Hamiltonian oh yeah I did right here the + + + align:start position:0% +Hamiltonian oh yeah I did right here the +Hamiltonian is H bar Omega + + align:start position:0% +Hamiltonian is H bar Omega + + + align:start position:0% +Hamiltonian is H bar Omega +a a dagger minus 1/2 or if we reverse + + align:start position:0% +a a dagger minus 1/2 or if we reverse + + + align:start position:0% +a a dagger minus 1/2 or if we reverse +these it's equal to H bar Omega a dagger + + align:start position:0% +these it's equal to H bar Omega a dagger + + + align:start position:0% +these it's equal to H bar Omega a dagger +A plus 1/2 so we can use either one + + align:start position:0% + + + + align:start position:0% + +so I'm using that one and so except I + + align:start position:0% +so I'm using that one and so except I + + + align:start position:0% +so I'm using that one and so except I +wanted a dagger here okay because we + + align:start position:0% +wanted a dagger here okay because we + + + align:start position:0% +wanted a dagger here okay because we +wanna show what the Hamiltonian does to + + align:start position:0% +wanna show what the Hamiltonian does to + + + align:start position:0% +wanna show what the Hamiltonian does to +this okay now we can pull an a dagger + + align:start position:0% +this okay now we can pull an a dagger + + + align:start position:0% +this okay now we can pull an a dagger +out to the right right because this the + + align:start position:0% +out to the right right because this the + + + align:start position:0% +out to the right right because this the +1/2 times a dagger well that the matter + + align:start position:0% +1/2 times a dagger well that the matter + + + align:start position:0% +1/2 times a dagger well that the matter +this a dagger a a dagger + + align:start position:0% +this a dagger a a dagger + + + align:start position:0% +this a dagger a a dagger +well we can pull this a dagger out so we + + align:start position:0% +well we can pull this a dagger out so we + + + align:start position:0% +well we can pull this a dagger out so we +have h-bar Omega a dagger is equal to a + + align:start position:0% +have h-bar Omega a dagger is equal to a + + + align:start position:0% +have h-bar Omega a dagger is equal to a +a dagger plus 1/2 sy V now we use our + + align:start position:0% +a dagger plus 1/2 sy V now we use our + + + align:start position:0% +a dagger plus 1/2 sy V now we use our +magic commutator trick to replace this + + align:start position:0% +magic commutator trick to replace this + + + align:start position:0% +magic commutator trick to replace this +by a dagger a + + align:start position:0% + + + + align:start position:0% + +plus one okay so now we have h-bar Omega + + align:start position:0% +plus one okay so now we have h-bar Omega + + + align:start position:0% +plus one okay so now we have h-bar Omega +a dagger and we have a dagger A plus + + align:start position:0% +a dagger and we have a dagger A plus + + + align:start position:0% +a dagger and we have a dagger A plus +three-halves 5e well this is e V Plus H + + align:start position:0% +three-halves 5e well this is e V Plus H + + + align:start position:0% +three-halves 5e well this is e V Plus H +bar Omega we've increased the number + + align:start position:0% +bar Omega we've increased the number + + + align:start position:0% +bar Omega we've increased the number +that started here here is e V that was + + align:start position:0% +that started here here is e V that was + + + align:start position:0% +that started here here is e V that was +evie plus 1 and so now we have no + + align:start position:0% +evie plus 1 and so now we have no + + + align:start position:0% +evie plus 1 and so now we have no +operators in here and we can stick the a + + align:start position:0% +operators in here and we can stick the a + + + align:start position:0% +operators in here and we can stick the a +dagger back here and so we have h bar + + align:start position:0% +dagger back here and so we have h bar + + + align:start position:0% +dagger back here and so we have h bar +omega e v plus 1 a dagger + + align:start position:0% + + + + align:start position:0% + +well what we have here we have an + + align:start position:0% +well what we have here we have an + + + align:start position:0% +well what we have here we have an +operator we have this function we have + + align:start position:0% +operator we have this function we have + + + align:start position:0% +operator we have this function we have +some constant times the same function so + + align:start position:0% +some constant times the same function so + + + align:start position:0% +some constant times the same function so +what we've shown is that this thing is + + align:start position:0% +what we've shown is that this thing is + + + align:start position:0% +what we've shown is that this thing is +an eigenfunction of the hamiltonian that + + align:start position:0% +an eigenfunction of the hamiltonian that + + + align:start position:0% +an eigenfunction of the hamiltonian that +belongs to the eigenvalue e v plus one + + align:start position:0% +belongs to the eigenvalue e v plus one + + + align:start position:0% +belongs to the eigenvalue e v plus one +we've increased the energy by one so + + align:start position:0% +we've increased the energy by one so + + + align:start position:0% +we've increased the energy by one so +what we have so so we can show that we + + align:start position:0% +what we have so so we can show that we + + + align:start position:0% +what we have so so we can show that we +apply a dagger to any function we + + align:start position:0% +apply a dagger to any function we + + + align:start position:0% +apply a dagger to any function we +increase its energy and we can do this + + align:start position:0% +increase its energy and we can do this + + + align:start position:0% +increase its energy and we can do this +forever we could also do a similar thing + + align:start position:0% +forever we could also do a similar thing + + + align:start position:0% +forever we could also do a similar thing +if we apply a to Saifee we can go down + + align:start position:0% +if we apply a to Saifee we can go down + + + align:start position:0% +if we apply a to Saifee we can go down +but at some point we run out of steam + + align:start position:0% +but at some point we run out of steam + + + align:start position:0% +but at some point we run out of steam +because we've gone gone to the lowest + + align:start position:0% +because we've gone gone to the lowest + + + align:start position:0% +because we've gone gone to the lowest +energy and if we go lower we get zero we + + align:start position:0% +energy and if we go lower we get zero we + + + align:start position:0% +energy and if we go lower we get zero we +get so a operating on sy min gives zero + + align:start position:0% +get so a operating on sy min gives zero + + + align:start position:0% +get so a operating on sy min gives zero +so we have this stack of energy levels + + align:start position:0% +so we have this stack of energy levels + + + align:start position:0% +so we have this stack of energy levels +and wave functions and we have the same + + align:start position:0% +and wave functions and we have the same + + + align:start position:0% +and wave functions and we have the same +stack being repeated as we go down but + + align:start position:0% +stack being repeated as we go down but + + + align:start position:0% +stack being repeated as we go down but +this one has an end + + align:start position:0% + + + + align:start position:0% + +okay so we bring back what a is and so a + + align:start position:0% +okay so we bring back what a is and so a + + + align:start position:0% +okay so we bring back what a is and so a +dive in is zero that's the equation we + + align:start position:0% +dive in is zero that's the equation we + + + align:start position:0% +dive in is zero that's the equation we +bring in what Amon is it's I mean but + + align:start position:0% +bring in what Amon is it's I mean but + + + align:start position:0% +bring in what Amon is it's I mean but +what a is and it's I P little X plus X + + align:start position:0% + + + + align:start position:0% + +so we do some algebra and what we end up + + align:start position:0% +so we do some algebra and what we end up + + + align:start position:0% +so we do some algebra and what we end up +with is a differential equation so I'm + + align:start position:0% +with is a differential equation so I'm + + + align:start position:0% +with is a differential equation so I'm +in the X is equal to again a little bit + + align:start position:0% +in the X is equal to again a little bit + + + align:start position:0% +in the X is equal to again a little bit +more algebra minus mu Omega over H bar + + align:start position:0% +more algebra minus mu Omega over H bar + + + align:start position:0% +more algebra minus mu Omega over H bar +times sine then so what function gives + + align:start position:0% +times sine then so what function gives + + + align:start position:0% +times sine then so what function gives +there's an X in here too so what + + align:start position:0% +there's an X in here too so what + + + align:start position:0% +there's an X in here too so what +function has a derivative which is the + + align:start position:0% +function has a derivative which is the + + + align:start position:0% +function has a derivative which is the +function you had started with times the + + align:start position:0% +function you had started with times the + + + align:start position:0% +function you had started with times the +variable times a constant okay and so + + align:start position:0% +variable times a constant okay and so + + + align:start position:0% +variable times a constant okay and so +the answer to that is that sigh men + + align:start position:0% +the answer to that is that sigh men + + + align:start position:0% +the answer to that is that sigh men +asked to have the form some + + align:start position:0% +asked to have the form some + + + align:start position:0% +asked to have the form some +normalization factor times e to the + + align:start position:0% +normalization factor times e to the + + + align:start position:0% +normalization factor times e to the +minus M Omega or mu Omega sorry you over + + align:start position:0% +minus M Omega or mu Omega sorry you over + + + align:start position:0% +minus M Omega or mu Omega sorry you over +to H bar x squared a Gaussian well had + + align:start position:0% +to H bar x squared a Gaussian well had + + + align:start position:0% +to H bar x squared a Gaussian well had +to be a Gaussian right we know when we + + align:start position:0% +to be a Gaussian right we know when we + + + align:start position:0% +to be a Gaussian right we know when we +did the algebra this we're going to get + + align:start position:0% +did the algebra this we're going to get + + + align:start position:0% +did the algebra this we're going to get +some function times a Gaussian but for + + align:start position:0% +some function times a Gaussian but for + + + align:start position:0% +some function times a Gaussian but for +the lowest function the hermite + + align:start position:0% +the lowest function the hermite + + + align:start position:0% +the lowest function the hermite +polynomial is one and all there is is a + + align:start position:0% +polynomial is one and all there is is a + + + align:start position:0% +polynomial is one and all there is is a +Gaussian and so it says well we found + + align:start position:0% +Gaussian and so it says well we found + + + align:start position:0% +Gaussian and so it says well we found +the lowest level + + align:start position:0% +the lowest level + + + align:start position:0% +the lowest level +and we can normalize it and so let's + + align:start position:0% +and we can normalize it and so let's + + + align:start position:0% +and we can normalize it and so let's +start over here + + align:start position:0% + + + + align:start position:0% + +so what we have found is Simon of X is + + align:start position:0% +so what we have found is Simon of X is + + + align:start position:0% +so what we have found is Simon of X is +equal to MU Omega over PI H bar to the + + align:start position:0% +equal to MU Omega over PI H bar to the + + + align:start position:0% +equal to MU Omega over PI H bar to the +1/4 power e to the minus u Omega over 2 + + align:start position:0% +1/4 power e to the minus u Omega over 2 + + + align:start position:0% +1/4 power e to the minus u Omega over 2 +H bar expert well that's useful we knew + + align:start position:0% +H bar expert well that's useful we knew + + + align:start position:0% +H bar expert well that's useful we knew +that but this time we got it out of a + + align:start position:0% +that but this time we got it out of a + + + align:start position:0% +that but this time we got it out of a +completely different path and now we can + + align:start position:0% +completely different path and now we can + + + align:start position:0% +completely different path and now we can +get all higher V by a dagger a dagger + + align:start position:0% +get all higher V by a dagger a dagger + + + align:start position:0% +get all higher V by a dagger a dagger +etcetera so remember we don't care + + align:start position:0% +etcetera so remember we don't care + + + align:start position:0% +etcetera so remember we don't care +anything about what the function is we + + align:start position:0% +anything about what the function is we + + + align:start position:0% +anything about what the function is we +just know that we can bring it in and + + align:start position:0% +just know that we can bring it in and + + + align:start position:0% +just know that we can bring it in and +get rid of it as well because what we + + align:start position:0% +get rid of it as well because what we + + + align:start position:0% +get rid of it as well because what we +want is the values of integrals + + align:start position:0% +want is the values of integrals + + + align:start position:0% +want is the values of integrals +involving that function and some + + align:start position:0% +involving that function and some + + + align:start position:0% +involving that function and some +operator so but yeah we can have all of + + align:start position:0% +operator so but yeah we can have all of + + + align:start position:0% +operator so but yeah we can have all of +those functions and this is a way of + + align:start position:0% +those functions and this is a way of + + + align:start position:0% +those functions and this is a way of +generating all of the functions and so + + align:start position:0% +generating all of the functions and so + + + align:start position:0% +generating all of the functions and so +if we want to + + align:start position:0% +if we want to + + + align:start position:0% +if we want to +sigh V we would do a dagger the V power + + align:start position:0% + + + + align:start position:0% + +divided by the dagger IV the what do you + + align:start position:0% +divided by the dagger IV the what do you + + + align:start position:0% +divided by the dagger IV the what do you +call this with an exclamation point + + align:start position:0% +call this with an exclamation point + + + align:start position:0% +call this with an exclamation point +factorial ha so we apply this operator + + align:start position:0% +factorial ha so we apply this operator + + + align:start position:0% +factorial ha so we apply this operator +that raises us to high at whatever level + + align:start position:0% +that raises us to high at whatever level + + + align:start position:0% +that raises us to high at whatever level +we want and starting from this Gaussian + + align:start position:0% +we want and starting from this Gaussian + + + align:start position:0% +we want and starting from this Gaussian +at the bottom and we have this + + align:start position:0% +at the bottom and we have this + + + align:start position:0% +at the bottom and we have this +normalization factor which cancels out + + align:start position:0% +normalization factor which cancels out + + + align:start position:0% +normalization factor which cancels out +at the fact the the stuff that you get + + align:start position:0% +at the fact the the stuff that you get + + + align:start position:0% +at the fact the the stuff that you get +by applying maybe ok so + + align:start position:0% + + + + align:start position:0% + +now there's some more logic in my notes + + align:start position:0% +now there's some more logic in my notes + + + align:start position:0% +now there's some more logic in my notes +and I don't want to do that but what + + align:start position:0% +and I don't want to do that but what + + + align:start position:0% +and I don't want to do that but what +we'd like to be able to show is that a + + align:start position:0% +we'd like to be able to show is that a + + + align:start position:0% +we'd like to be able to show is that a +dagger on side V gives some constant and + + align:start position:0% +dagger on side V gives some constant and + + + align:start position:0% +dagger on side V gives some constant and +the discuss that has some value we're + + align:start position:0% +the discuss that has some value we're + + + align:start position:0% +the discuss that has some value we're +going to evaluate what it is and + + align:start position:0% +going to evaluate what it is and + + + align:start position:0% +going to evaluate what it is and +similarly a side V gives DV and some + + align:start position:0% +similarly a side V gives DV and some + + + align:start position:0% +similarly a side V gives DV and some +constant V equal to V minus 1/2 okay we + + align:start position:0% +constant V equal to V minus 1/2 okay we + + + align:start position:0% +constant V equal to V minus 1/2 okay we +can derive those things and I'm not + + align:start position:0% +can derive those things and I'm not + + + align:start position:0% +can derive those things and I'm not +going to waste time deriving them I'm + + align:start position:0% +going to waste time deriving them I'm + + + align:start position:0% +going to waste time deriving them I'm +going to just give you the values but we + + align:start position:0% +going to just give you the values but we + + + align:start position:0% +going to just give you the values but we +already know that cv is square root of V + + align:start position:0% +already know that cv is square root of V + + + align:start position:0% +already know that cv is square root of V +plus 1/2 B plus 1 and DV and you can see + + align:start position:0% +plus 1/2 B plus 1 and DV and you can see + + + align:start position:0% +plus 1/2 B plus 1 and DV and you can see +the derivation of my notes I don't think + + align:start position:0% +the derivation of my notes I don't think + + + align:start position:0% +the derivation of my notes I don't think +going through them is going to be + + align:start position:0% +going through them is going to be + + + align:start position:0% +going through them is going to be +instructive and that's just going to be + + align:start position:0% +instructive and that's just going to be + + + align:start position:0% +instructive and that's just going to be +the ok so now we have something it's + + align:start position:0% +the ok so now we have something it's + + + align:start position:0% +the ok so now we have something it's +wonderful because everything you need to + + align:start position:0% +wonderful because everything you need to + + + align:start position:0% +wonderful because everything you need to +know about getting numbers concerning + + align:start position:0% +know about getting numbers concerning + + + align:start position:0% +know about getting numbers concerning +harmonic oscillator is obtained from + + align:start position:0% +harmonic oscillator is obtained from + + + align:start position:0% +harmonic oscillator is obtained from +these five equations a dagger on side V + + align:start position:0% +these five equations a dagger on side V + + + align:start position:0% +these five equations a dagger on side V +is V plus 1 + + align:start position:0% + + + + align:start position:0% + +hey I'm IV is V sorry B minus 1 I've + + align:start position:0% +hey I'm IV is V sorry B minus 1 I've + + + align:start position:0% +hey I'm IV is V sorry B minus 1 I've +said this before but you know these are + + align:start position:0% +said this before but you know these are + + + align:start position:0% +said this before but you know these are +the most useful things you'll ever + + align:start position:0% +the most useful things you'll ever + + + align:start position:0% +the most useful things you'll ever +encounter we have this thing called a + + align:start position:0% +encounter we have this thing called a + + + align:start position:0% +encounter we have this thing called a +number operator and that number operator + + align:start position:0% +number operator and that number operator + + + align:start position:0% +number operator and that number operator +is a dagger at a and the number operator + + align:start position:0% +is a dagger at a and the number operator + + + align:start position:0% +is a dagger at a and the number operator +operating on side V gives V by V and so + + align:start position:0% +operating on side V gives V by V and so + + + align:start position:0% +operating on side V gives V by V and so +that's a kind of benign operator that it + + align:start position:0% +that's a kind of benign operator that it + + + align:start position:0% +that's a kind of benign operator that it +can suck up all sorts of come + + align:start position:0% +can suck up all sorts of come + + + align:start position:0% +can suck up all sorts of come +the factors of a dagger a because it + + align:start position:0% +the factors of a dagger a because it + + + align:start position:0% +the factors of a dagger a because it +just gives it a useful thing and then we + + align:start position:0% +just gives it a useful thing and then we + + + align:start position:0% +just gives it a useful thing and then we +have a dagger and this is one well you + + align:start position:0% +have a dagger and this is one well you + + + align:start position:0% +have a dagger and this is one well you +you sort of know it's going to be 1 + + align:start position:0% +you sort of know it's going to be 1 + + + align:start position:0% +you sort of know it's going to be 1 +because a a dagger it gives an increase + + align:start position:0% +because a a dagger it gives an increase + + + align:start position:0% +because a a dagger it gives an increase +it gives V plus 1 and a and an a gives + + align:start position:0% +it gives V plus 1 and a and an a gives + + + align:start position:0% +it gives V plus 1 and a and an a gives +via B minus 1 so it's plus 1 not minus 1 + + align:start position:0% +via B minus 1 so it's plus 1 not minus 1 + + + align:start position:0% +via B minus 1 so it's plus 1 not minus 1 +and you know that it's hardwired ok well + + align:start position:0% +and you know that it's hardwired ok well + + + align:start position:0% +and you know that it's hardwired ok well +I did it I got to the point where it + + align:start position:0% +I did it I got to the point where it + + + align:start position:0% +I did it I got to the point where it +starts to get interesting so we're going + + align:start position:0% +starts to get interesting so we're going + + + align:start position:0% +starts to get interesting so we're going +to be using this notation a dagger and a + + align:start position:0% +to be using this notation a dagger and a + + + align:start position:0% +to be using this notation a dagger and a +for all sorts of stuff and one sort of + + align:start position:0% +for all sorts of stuff and one sort of + + + align:start position:0% +for all sorts of stuff and one sort of +thing is transition intensities and + + align:start position:0% +thing is transition intensities and + + + align:start position:0% +thing is transition intensities and +selections so you have a harmonic + + align:start position:0% +selections so you have a harmonic + + + align:start position:0% +selections so you have a harmonic +oscillator monarch oscillator is say a + + align:start position:0% +oscillator monarch oscillator is say a + + + align:start position:0% +oscillator monarch oscillator is say a +diatomic molecule which is heteronuclear + + align:start position:0% +diatomic molecule which is heteronuclear + + + align:start position:0% +diatomic molecule which is heteronuclear +and so as the molecule vibrates you have + + align:start position:0% +and so as the molecule vibrates you have + + + align:start position:0% +and so as the molecule vibrates you have +a dipole moment which is oscillating and + + align:start position:0% +a dipole moment which is oscillating and + + + align:start position:0% +a dipole moment which is oscillating and +so any electric field oscillating + + align:start position:0% +so any electric field oscillating + + + align:start position:0% +so any electric field oscillating +electric field will grab a hold of that + + align:start position:0% +electric field will grab a hold of that + + + align:start position:0% +electric field will grab a hold of that +dipole moment and stretch or compress it + + align:start position:0% +dipole moment and stretch or compress it + + + align:start position:0% +dipole moment and stretch or compress it +especially if that field is in resonance + + align:start position:0% +especially if that field is in resonance + + + align:start position:0% +especially if that field is in resonance +with h-bar Omega and I'm gonna I've got + + align:start position:0% +with h-bar Omega and I'm gonna I've got + + + align:start position:0% +with h-bar Omega and I'm gonna I've got +some beautiful animations showing this + + align:start position:0% +some beautiful animations showing this + + + align:start position:0% +some beautiful animations showing this +but we can't do that until we have + + align:start position:0% +but we can't do that until we have + + + align:start position:0% +but we can't do that until we have +time-dependent quantum mechanics so we + + align:start position:0% +time-dependent quantum mechanics so we + + + align:start position:0% +time-dependent quantum mechanics so we +have a time-dependent radiation field + + align:start position:0% +have a time-dependent radiation field + + + align:start position:0% +have a time-dependent radiation field +which is going to interact with the + + align:start position:0% +which is going to interact with the + + + align:start position:0% +which is going to interact with the +dipole associated with the vibrating + + align:start position:0% +dipole associated with the vibrating + + + align:start position:0% +dipole associated with the vibrating +molecule and it's going to cause + + align:start position:0% +molecule and it's going to cause + + + align:start position:0% +molecule and it's going to cause +transitions and so we can write the + + align:start position:0% +transitions and so we can write the + + + align:start position:0% +transitions and so we can write the +operator + + align:start position:0% +operator + + + align:start position:0% +operator +the quantum mechanical operator that + + align:start position:0% +the quantum mechanical operator that + + + align:start position:0% +the quantum mechanical operator that +causes the transitions this is the + + align:start position:0% +causes the transitions this is the + + + align:start position:0% +causes the transitions this is the +electric dipole moment operator as a + + align:start position:0% +electric dipole moment operator as a + + + align:start position:0% +electric dipole moment operator as a +function of coordinate and we can do a + + align:start position:0% +function of coordinate and we can do a + + + align:start position:0% +function of coordinate and we can do a +power series expansion of this and we + + align:start position:0% +power series expansion of this and we + + + align:start position:0% +power series expansion of this and we +have so we have u 0 the constant term + + align:start position:0% +have so we have u 0 the constant term + + + align:start position:0% +have so we have u 0 the constant term +the first derivative of the dipole with + + align:start position:0% +the first derivative of the dipole with + + + align:start position:0% +the first derivative of the dipole with +respect to X and the second derivative + + align:start position:0% +respect to X and the second derivative + + + align:start position:0% +respect to X and the second derivative +of the dipole with respect to X and so + + align:start position:0% +of the dipole with respect to X and so + + + align:start position:0% +of the dipole with respect to X and so +we have the X cofactor and the x squared + + align:start position:0% +we have the X cofactor and the x squared + + + align:start position:0% +we have the X cofactor and the x squared +cofactor and so this guy doesn't have + + align:start position:0% +cofactor and so this guy doesn't have + + + align:start position:0% +cofactor and so this guy doesn't have +any X on it it's a constant the only + + align:start position:0% +any X on it it's a constant the only + + + align:start position:0% +any X on it it's a constant the only +integrals involving the only integrals + + align:start position:0% +integrals involving the only integrals + + + align:start position:0% +integrals involving the only integrals +are Delta V V Prime following the + + align:start position:0% +are Delta V V Prime following the + + + align:start position:0% +are Delta V V Prime following the +selection will Delta V V prime so these + + align:start position:0% +selection will Delta V V prime so these + + + align:start position:0% +selection will Delta V V prime so these +integrals are zero unless V and V prime + + align:start position:0% +integrals are zero unless V and V prime + + + align:start position:0% +integrals are zero unless V and V prime +are the same and that that's as well + + align:start position:0% +are the same and that that's as well + + + align:start position:0% +are the same and that that's as well +there's an oscillating field is going to + + align:start position:0% +there's an oscillating field is going to + + + align:start position:0% +there's an oscillating field is going to +do anything Q to it it's just going to + + align:start position:0% +do anything Q to it it's just going to + + + align:start position:0% +do anything Q to it it's just going to +leave it in the same vibrational level + + align:start position:0% +leave it in the same vibrational level + + + align:start position:0% +leave it in the same vibrational level +but it might have a electric stark + + align:start position:0% +but it might have a electric stark + + + align:start position:0% +but it might have a electric stark +effect but that's something else okay so + + align:start position:0% +effect but that's something else okay so + + + align:start position:0% +effect but that's something else okay so +so this term does nothing as far as + + align:start position:0% +so this term does nothing as far as + + + align:start position:0% +so this term does nothing as far as +vibration is concerned this guy which is + + align:start position:0% +vibration is concerned this guy which is + + + align:start position:0% +vibration is concerned this guy which is +a plus a dagger as a selection of all + + align:start position:0% +a plus a dagger as a selection of all + + + align:start position:0% +a plus a dagger as a selection of all +Delta V of plus minus 1 + + align:start position:0% +Delta V of plus minus 1 + + + align:start position:0% +Delta V of plus minus 1 +and this guy as a selection rule Delta V + + align:start position:0% +and this guy as a selection rule Delta V + + + align:start position:0% +and this guy as a selection rule Delta V +of plus and minus 2 and 0 so if we're + + align:start position:0% +of plus and minus 2 and 0 so if we're + + + align:start position:0% +of plus and minus 2 and 0 so if we're +interested in the intensities of + + align:start position:0% +interested in the intensities of + + + align:start position:0% +interested in the intensities of +vibrational transitions it says well + + align:start position:0% +vibrational transitions it says well + + + align:start position:0% +vibrational transitions it says well +this is the important term and it causes + + align:start position:0% +this is the important term and it causes + + + align:start position:0% +this is the important term and it causes +transitions changing the vibrational + + align:start position:0% +transitions changing the vibrational + + + align:start position:0% +transitions changing the vibrational +quantum number by one which is called + + align:start position:0% +quantum number by one which is called + + + align:start position:0% +quantum number by one which is called +the fundamental + + align:start position:0% +the fundamental + + + align:start position:0% +the fundamental +this gives rise to overtones so all of a + + align:start position:0% +this gives rise to overtones so all of a + + + align:start position:0% +this gives rise to overtones so all of a +sudden we're in real a real problem land + + align:start position:0% +sudden we're in real a real problem land + + + align:start position:0% +sudden we're in real a real problem land +where if we're looking at vibrational + + align:start position:0% +where if we're looking at vibrational + + + align:start position:0% +where if we're looking at vibrational +transitions in a molecule that this + + align:start position:0% +transitions in a molecule that this + + + align:start position:0% +transitions in a molecule that this +enables us to calculate what's important + + align:start position:0% +enables us to calculate what's important + + + align:start position:0% +enables us to calculate what's important +or to say these are the intensities I + + align:start position:0% +or to say these are the intensities I + + + align:start position:0% +or to say these are the intensities I +measure and these are the first and + + align:start position:0% +measure and these are the first and + + + align:start position:0% +measure and these are the first and +second derivative of the dipole moment + + align:start position:0% +second derivative of the dipole moment + + + align:start position:0% +second derivative of the dipole moment +operator is a function of you know clear + + align:start position:0% +operator is a function of you know clear + + + align:start position:0% +operator is a function of you know clear +distance + + align:start position:0% +distance + + + align:start position:0% +distance +didn't that need okay I've gone so fast + + align:start position:0% +didn't that need okay I've gone so fast + + + align:start position:0% +didn't that need okay I've gone so fast +I'm a more or less at the end of my + + align:start position:0% +I'm a more or less at the end of my + + + align:start position:0% +I'm a more or less at the end of my +notes but I can Blair on for a while so + + align:start position:0% +notes but I can Blair on for a while so + + + align:start position:0% +notes but I can Blair on for a while so +suppose you have some integral involving + + align:start position:0% +suppose you have some integral involving + + + align:start position:0% +suppose you have some integral involving +an operator and the vibrational wave + + align:start position:0% +an operator and the vibrational wave + + + align:start position:0% +an operator and the vibrational wave +function so so we have sine V star some + + align:start position:0% +function so so we have sine V star some + + + align:start position:0% +function so so we have sine V star some +operator sorry V prime DX and we'd like + + align:start position:0% +operator sorry V prime DX and we'd like + + + align:start position:0% +operator sorry V prime DX and we'd like +to know how to focus our energies we're + + align:start position:0% +to know how to focus our energies we're + + + align:start position:0% +to know how to focus our energies we're +very busy people we don't want to + + align:start position:0% +very busy people we don't want to + + + align:start position:0% +very busy people we don't want to +evaluate integrals that come out to be + + align:start position:0% +evaluate integrals that come out to be + + + align:start position:0% +evaluate integrals that come out to be +zero we'd like to just know so if this + + align:start position:0% +zero we'd like to just know so if this + + + align:start position:0% +zero we'd like to just know so if this +operator is some function of X or + + align:start position:0% +operator is some function of X or + + + align:start position:0% +operator is some function of X or +function of P we'd have a power series + + align:start position:0% +function of P we'd have a power series + + + align:start position:0% +function of P we'd have a power series +expansion of the operator and we then + + align:start position:0% +expansion of the operator and we then + + + align:start position:0% +expansion of the operator and we then +know what the selection rules are so + + align:start position:0% +know what the selection rules are so + + + align:start position:0% +know what the selection rules are so +usually use it you look at the operator + + align:start position:0% +usually use it you look at the operator + + + align:start position:0% +usually use it you look at the operator +and you find that it is a function it's + + align:start position:0% +and you find that it is a function it's + + + align:start position:0% +and you find that it is a function it's +a linear quadratic cubic function of X + + align:start position:0% +a linear quadratic cubic function of X + + + align:start position:0% +a linear quadratic cubic function of X +the leading term is usually linear bang + + align:start position:0% +the leading term is usually linear bang + + + align:start position:0% +the leading term is usually linear bang +you have a delta V of +1 selection rule + + align:start position:0% +you have a delta V of +1 selection rule + + + align:start position:0% +you have a delta V of +1 selection rule +or if someone has bothered to actually + + align:start position:0% +or if someone has bothered to actually + + + align:start position:0% +or if someone has bothered to actually +convert the operator to some form that's + + align:start position:0% +convert the operator to some form that's + + + align:start position:0% +convert the operator to some form that's +the operator + + align:start position:0% + + + + align:start position:0% + +this this might have some form a dagger + + align:start position:0% +this this might have some form a dagger + + + align:start position:0% +this this might have some form a dagger +cubed times some constant okay so if the + + align:start position:0% +cubed times some constant okay so if the + + + align:start position:0% +cubed times some constant okay so if the +operator looks like a dagger cubed we + + align:start position:0% +operator looks like a dagger cubed we + + + align:start position:0% +operator looks like a dagger cubed we +know that the selection rule is V 2 V + + align:start position:0% +know that the selection rule is V 2 V + + + align:start position:0% +know that the selection rule is V 2 V +plus 3 and we know that the matrix on + + align:start position:0% +plus 3 and we know that the matrix on + + + align:start position:0% +plus 3 and we know that the matrix on +the integral is V plus 1 times V plus 2 + + align:start position:0% +the integral is V plus 1 times V plus 2 + + + align:start position:0% +the integral is V plus 1 times V plus 2 +times V plus 3 square root of that and + + align:start position:0% +times V plus 3 square root of that and + + + align:start position:0% +times V plus 3 square root of that and +the constant so there's a huge number of + + align:start position:0% +the constant so there's a huge number of + + + align:start position:0% +the constant so there's a huge number of +problems that instead of being pages and + + align:start position:0% +problems that instead of being pages and + + + align:start position:0% +problems that instead of being pages and +pages of algebra are just reduced to + + align:start position:0% +pages of algebra are just reduced to + + + align:start position:0% +pages of algebra are just reduced to +something that you can tell by + + align:start position:0% +something that you can tell by + + + align:start position:0% +something that you can tell by +inspection so one of the the tricks is + + align:start position:0% +inspection so one of the the tricks is + + + align:start position:0% +inspection so one of the the tricks is +we have an operator like x squared or X + + align:start position:0% +we have an operator like x squared or X + + + align:start position:0% +we have an operator like x squared or X +cubed what we want to do is write this + + align:start position:0% +cubed what we want to do is write this + + + align:start position:0% +cubed what we want to do is write this +in terms of a squared a dagger squared + + align:start position:0% +in terms of a squared a dagger squared + + + align:start position:0% +in terms of a squared a dagger squared +and maybe some combination of a dagger a + + align:start position:0% +and maybe some combination of a dagger a + + + align:start position:0% +and maybe some combination of a dagger a +so we want to take the a dagger A's with + + align:start position:0% +so we want to take the a dagger A's with + + + align:start position:0% +so we want to take the a dagger A's with +the a a daggers and combine them using + + align:start position:0% +the a a daggers and combine them using + + + align:start position:0% +the a a daggers and combine them using +the commutation rule and then we have + + align:start position:0% +the commutation rule and then we have + + + align:start position:0% +the commutation rule and then we have +expressed this in this maximally simple + + align:start position:0% +expressed this in this maximally simple + + + align:start position:0% +expressed this in this maximally simple +form and then you just apply a squared + + align:start position:0% +form and then you just apply a squared + + + align:start position:0% +form and then you just apply a squared +apply a dagger squared and you apply + + align:start position:0% +apply a dagger squared and you apply + + + align:start position:0% +apply a dagger squared and you apply +this and you've got the value of the + + align:start position:0% +this and you've got the value of the + + + align:start position:0% +this and you've got the value of the +integral so if you're a busy person and + + align:start position:0% +integral so if you're a busy person and + + + align:start position:0% +integral so if you're a busy person and +you want to actually calculate stuff you + + align:start position:0% +you want to actually calculate stuff you + + + align:start position:0% +you want to actually calculate stuff you +want to know how to reduce operators + + align:start position:0% +want to know how to reduce operators + + + align:start position:0% +want to know how to reduce operators +usually expressed as some power of the + + align:start position:0% +usually expressed as some power of the + + + align:start position:0% +usually expressed as some power of the +coordinate or the momentum into a sum of + + align:start position:0% +coordinate or the momentum into a sum of + + + align:start position:0% +coordinate or the momentum into a sum of +terms involving these organized products + + align:start position:0% +terms involving these organized products + + + align:start position:0% +terms involving these organized products +of A's and a daggers and you're going to + + align:start position:0% +of A's and a daggers and you're going to + + + align:start position:0% +of A's and a daggers and you're going to +be absolutely shocked at how + + align:start position:0% +be absolutely shocked at how + + + align:start position:0% +be absolutely shocked at how +perturbation theory which leads to + + align:start position:0% +perturbation theory which leads to + + + align:start position:0% +perturbation theory which leads to +basically all of the formulas in + + align:start position:0% +basically all of the formulas in + + + align:start position:0% +basically all of the formulas in +spectroscopy + + align:start position:0% +spectroscopy + + + align:start position:0% +spectroscopy +it's an ugly theory but it reduces + + align:start position:0% +it's an ugly theory but it reduces + + + align:start position:0% +it's an ugly theory but it reduces +everything to things that you can just + + align:start position:0% +everything to things that you can just + + + align:start position:0% +everything to things that you can just +write down at the speed of your pen or + + align:start position:0% +write down at the speed of your pen or + + + align:start position:0% +write down at the speed of your pen or +pencil and and that's a fantastic thing + + align:start position:0% +pencil and and that's a fantastic thing + + + align:start position:0% +pencil and and that's a fantastic thing +so you can't do this with the particle + + align:start position:0% +so you can't do this with the particle + + + align:start position:0% +so you can't do this with the particle +in a box you can't do this with a + + align:start position:0% +in a box you can't do this with a + + + align:start position:0% +in a box you can't do this with a +hydrogen atom you can't do this with a + + align:start position:0% +hydrogen atom you can't do this with a + + + align:start position:0% +hydrogen atom you can't do this with a +rigid rope well you can do some of this + + align:start position:0% +rigid rope well you can do some of this + + + align:start position:0% +rigid rope well you can do some of this +with a rigid rotor but the harmonic + + align:start position:0% +with a rigid rotor but the harmonic + + + align:start position:0% +with a rigid rotor but the harmonic +oscillator is so ubiquitous because + + align:start position:0% +oscillator is so ubiquitous because + + + align:start position:0% +oscillator is so ubiquitous because +every one-dimensional problem is + + align:start position:0% +every one-dimensional problem is + + + align:start position:0% +every one-dimensional problem is +harmonic at the bottom and so you can + + align:start position:0% +harmonic at the bottom and so you can + + + align:start position:0% +harmonic at the bottom and so you can +use it and then you can put in the + + align:start position:0% +use it and then you can put in the + + + align:start position:0% +use it and then you can put in the +corrections but also because you want to + + align:start position:0% +corrections but also because you want to + + + align:start position:0% +corrections but also because you want to +describe dynamics you almost always use + + align:start position:0% +describe dynamics you almost always use + + + align:start position:0% +describe dynamics you almost always use +the harmonic oscillator because not only + + align:start position:0% +the harmonic oscillator because not only + + + align:start position:0% +the harmonic oscillator because not only +do you know the integrals but you know + + align:start position:0% +do you know the integrals but you know + + + align:start position:0% +do you know the integrals but you know +there's only a few normally you're going + + align:start position:0% +there's only a few normally you're going + + + align:start position:0% +there's only a few normally you're going +to be summing over an infinite number of + + align:start position:0% +to be summing over an infinite number of + + + align:start position:0% +to be summing over an infinite number of +quantum numbers and that takes time and + + align:start position:0% +quantum numbers and that takes time and + + + align:start position:0% +quantum numbers and that takes time and +it takes judgment to say well only + + align:start position:0% +it takes judgment to say well only + + + align:start position:0% +it takes judgment to say well only +certain of these are important but for + + align:start position:0% +certain of these are important but for + + + align:start position:0% +certain of these are important but for +the harmonic oscillator this sums are + + align:start position:0% +the harmonic oscillator this sums are + + + align:start position:0% +the harmonic oscillator this sums are +finite all of these things are wonderful + + align:start position:0% +finite all of these things are wonderful + + + align:start position:0% +finite all of these things are wonderful +and that's why whenever you look at a + + align:start position:0% +and that's why whenever you look at a + + + align:start position:0% +and that's why whenever you look at a +theory you're going to discover that + + align:start position:0% +theory you're going to discover that + + + align:start position:0% +theory you're going to discover that +hidden in there is the harmonic + + align:start position:0% +hidden in there is the harmonic + + + align:start position:0% +hidden in there is the harmonic +oscillator approximation because then + + align:start position:0% +oscillator approximation because then + + + align:start position:0% +oscillator approximation because then +everything is doable in no effort and + + align:start position:0% +everything is doable in no effort and + + + align:start position:0% +everything is doable in no effort and +sometimes when you look at a paper like + + align:start position:0% +sometimes when you look at a paper like + + + align:start position:0% +sometimes when you look at a paper like +that it doesn't show you the + + align:start position:0% +that it doesn't show you the + + + align:start position:0% +that it doesn't show you the +intermediate steps because everybody + + align:start position:0% +intermediate steps because everybody + + + align:start position:0% +intermediate steps because everybody +knows what a harmonic oscillator does + + align:start position:0% +knows what a harmonic oscillator does + + + align:start position:0% +knows what a harmonic oscillator does +and there's also a lot of insight + + align:start position:0% +and there's also a lot of insight + + + align:start position:0% +and there's also a lot of insight +because you know something like this + + align:start position:0% +because you know something like this + + + align:start position:0% +because you know something like this +this is an odd symmetry term this is an + + align:start position:0% +this is an odd symmetry term this is an + + + align:start position:0% +this is an odd symmetry term this is an +even symmetry term and there are all + + align:start position:0% +even symmetry term and there are all + + + align:start position:0% +even symmetry term and there are all +sorts of things that have to do with are + + align:start position:0% +sorts of things that have to do with are + + + align:start position:0% +sorts of things that have to do with are +you conserving symmetry or changing + + align:start position:0% +you conserving symmetry or changing + + + align:start position:0% +you conserving symmetry or changing +symmetry and sometimes there's the issue + + align:start position:0% +symmetry and sometimes there's the issue + + + align:start position:0% +symmetry and sometimes there's the issue +is how does the molecule spontaneously + + align:start position:0% +is how does the molecule spontaneously + + + align:start position:0% +is how does the molecule spontaneously +change symmetry by doing something + + align:start position:0% +change symmetry by doing something + + + align:start position:0% +change symmetry by doing something +interacting with a field or or hat + + align:start position:0% +interacting with a field or or hat + + + align:start position:0% +interacting with a field or or hat +interacting with some feature of the + + align:start position:0% +interacting with some feature of the + + + align:start position:0% +interacting with some feature of the +potential surface so this is a place + + align:start position:0% +potential surface so this is a place + + + align:start position:0% +potential surface so this is a place +where it's labor-saving and insight + + align:start position:0% +where it's labor-saving and insight + + + align:start position:0% +where it's labor-saving and insight +generating and it's really amazing + + align:start position:0% +generating and it's really amazing + + + align:start position:0% +generating and it's really amazing +so maybe you know maybe I've bored you + + align:start position:0% +so maybe you know maybe I've bored you + + + align:start position:0% +so maybe you know maybe I've bored you +with this but this is you know this is + + align:start position:0% +with this but this is you know this is + + + align:start position:0% +with this but this is you know this is +the beginning of almost every Theory the + + align:start position:0% +the beginning of almost every Theory the + + + align:start position:0% +the beginning of almost every Theory the +you'll encounter just because of the + + align:start position:0% +you'll encounter just because of the + + + align:start position:0% +you'll encounter just because of the +simplicity of the A's and a daggers okay + + align:start position:0% +simplicity of the A's and a daggers okay + + + align:start position:0% +simplicity of the A's and a daggers okay +I'm done + + align:start position:0% +I'm done + + + align:start position:0% +I'm done +thank you \ No newline at end of file diff --git a/40Sum5KfG1Q.txt b/40Sum5KfG1Q.txt new file mode 100644 index 0000000000000000000000000000000000000000..69add805f5c57ef829b51be370d9a784d7a04e51 --- /dev/null +++ b/40Sum5KfG1Q.txt @@ -0,0 +1,8355 @@ +align:start position:0% + +now at the time that um that Watson and + + align:start position:0% +now at the time that um that Watson and + + + align:start position:0% +now at the time that um that Watson and +C figured out the the structure of DNA + + align:start position:0% +C figured out the the structure of DNA + + + align:start position:0% +C figured out the the structure of DNA +you know it was sort of obvious that + + align:start position:0% +you know it was sort of obvious that + + + align:start position:0% +you know it was sort of obvious that +since the two strands are complimentary + + align:start position:0% +since the two strands are complimentary + + + align:start position:0% +since the two strands are complimentary +you could see how it replicated and they + + align:start position:0% +you could see how it replicated and they + + + align:start position:0% +you could see how it replicated and they +also uh got a they could see that + + align:start position:0% +also uh got a they could see that + + + align:start position:0% +also uh got a they could see that +somehow the information must be encoded + + align:start position:0% +somehow the information must be encoded + + + align:start position:0% +somehow the information must be encoded +in the sequence of of uh of um letters + + align:start position:0% +in the sequence of of uh of um letters + + + align:start position:0% +in the sequence of of uh of um letters +down the the strands of of the DNA but + + align:start position:0% +down the the strands of of the DNA but + + + align:start position:0% +down the the strands of of the DNA but +it wasn't obvious what the code was how + + align:start position:0% +it wasn't obvious what the code was how + + + align:start position:0% +it wasn't obvious what the code was how +it was arranged how it worked and in in + + align:start position:0% +it was arranged how it worked and in in + + + align:start position:0% +it was arranged how it worked and in in +principle uh it was anything you could + + align:start position:0% +principle uh it was anything you could + + + align:start position:0% +principle uh it was anything you could +do with with four letters and so I had I + + align:start position:0% +do with with four letters and so I had I + + + align:start position:0% +do with with four letters and so I had I +pointed out the other day this is sort + + align:start position:0% +pointed out the other day this is sort + + + align:start position:0% +pointed out the other day this is sort +of a four-letter + + align:start position:0% +of a four-letter + + + align:start position:0% +of a four-letter +alphabet and I think it's useful to + + align:start position:0% +alphabet and I think it's useful to + + + align:start position:0% +alphabet and I think it's useful to +think of it this way with uh a g c and T + + align:start position:0% +think of it this way with uh a g c and T + + + align:start position:0% +think of it this way with uh a g c and T +and RNA is also being a + + align:start position:0% +and RNA is also being a + + + align:start position:0% +and RNA is also being a +four-letter + + align:start position:0% +four-letter + + + align:start position:0% +four-letter +alphabet but proteins are actually a + + align:start position:0% +alphabet but proteins are actually a + + + align:start position:0% +alphabet but proteins are actually a +20l + + align:start position:0% + + + + align:start position:0% + +alphabet because there are 20 different + + align:start position:0% +alphabet because there are 20 different + + + align:start position:0% +alphabet because there are 20 different +amino + + align:start position:0% + + + + align:start position:0% + +acids and so somehow uh since one of the + + align:start position:0% +acids and so somehow uh since one of the + + + align:start position:0% +acids and so somehow uh since one of the +key things that the DNA had to do it was + + align:start position:0% +key things that the DNA had to do it was + + + align:start position:0% +key things that the DNA had to do it was +it somehow had to encode uh the the + + align:start position:0% +it somehow had to encode uh the the + + + align:start position:0% +it somehow had to encode uh the the +information for making the the proteins + + align:start position:0% +information for making the the proteins + + + align:start position:0% +information for making the the proteins +and it was there was a lot of work on + + align:start position:0% +and it was there was a lot of work on + + + align:start position:0% +and it was there was a lot of work on +protein biosynthesis at the time and it + + align:start position:0% +protein biosynthesis at the time and it + + + align:start position:0% +protein biosynthesis at the time and it +looked pretty complicated uh people had + + align:start position:0% +looked pretty complicated uh people had + + + align:start position:0% +looked pretty complicated uh people had +found that RNA seemed to be important + + align:start position:0% +found that RNA seemed to be important + + + align:start position:0% +found that RNA seemed to be important +cells that were making lots of protein + + align:start position:0% +cells that were making lots of protein + + + align:start position:0% +cells that were making lots of protein +had lots of RNA in them and another + + align:start position:0% +had lots of RNA in them and another + + + align:start position:0% +had lots of RNA in them and another +thing they noticed was if you looked in + + align:start position:0% +thing they noticed was if you looked in + + + align:start position:0% +thing they noticed was if you looked in +eukariotic cells the DNA stayed in the + + align:start position:0% +eukariotic cells the DNA stayed in the + + + align:start position:0% +eukariotic cells the DNA stayed in the +nucleus but the proteins were were out + + align:start position:0% +nucleus but the proteins were were out + + + align:start position:0% +nucleus but the proteins were were out +most of them were out in the cytoplasm + + align:start position:0% +most of them were out in the cytoplasm + + + align:start position:0% +most of them were out in the cytoplasm +and the evidence was that they they were + + align:start position:0% +and the evidence was that they they were + + + align:start position:0% +and the evidence was that they they were +made out in the cytoplasm so somehow the + + align:start position:0% +made out in the cytoplasm so somehow the + + + align:start position:0% +made out in the cytoplasm so somehow the +information had to get out of the + + align:start position:0% +information had to get out of the + + + align:start position:0% +information had to get out of the +nucleus where the DNA was + + align:start position:0% +nucleus where the DNA was + + + align:start position:0% +nucleus where the DNA was +and uh into the cytoplasm and + + align:start position:0% +and uh into the cytoplasm and + + + align:start position:0% +and uh into the cytoplasm and +biochemists were breaking cells open and + + align:start position:0% +biochemists were breaking cells open and + + + align:start position:0% +biochemists were breaking cells open and +trying to make cellular extracts that + + align:start position:0% +trying to make cellular extracts that + + + align:start position:0% +trying to make cellular extracts that +would synthesize proteins and I think + + align:start position:0% +would synthesize proteins and I think + + + align:start position:0% +would synthesize proteins and I think +it's fair to say at the time that it + + align:start position:0% +it's fair to say at the time that it + + + align:start position:0% +it's fair to say at the time that it +looked extremely + + align:start position:0% +looked extremely + + + align:start position:0% +looked extremely +complicated and so thinking about how + + align:start position:0% +complicated and so thinking about how + + + align:start position:0% +complicated and so thinking about how +DNA encoded information got translated + + align:start position:0% +DNA encoded information got translated + + + align:start position:0% +DNA encoded information got translated +in proteins was was a was a very complex + + align:start position:0% +in proteins was was a was a very complex + + + align:start position:0% +in proteins was was a was a very complex +uh issue but then actually there was a + + align:start position:0% +uh issue but then actually there was a + + + align:start position:0% +uh issue but then actually there was a +very interesting development that that + + align:start position:0% +very interesting development that that + + + align:start position:0% +very interesting development that that +uh had a strong influence in Watson and + + align:start position:0% +uh had a strong influence in Watson and + + + align:start position:0% +uh had a strong influence in Watson and +Crick and led to them getting crick in + + align:start position:0% +Crick and led to them getting crick in + + + align:start position:0% +Crick and led to them getting crick in +particular getting a a key insight into + + align:start position:0% +particular getting a a key insight into + + + align:start position:0% +particular getting a a key insight into +the nature of this coding problem + + align:start position:0% +the nature of this coding problem + + + align:start position:0% +the nature of this coding problem +there's a physicist uh George gaml Who + + align:start position:0% +there's a physicist uh George gaml Who + + + align:start position:0% +there's a physicist uh George gaml Who +some of you know he proposed The Big + + align:start position:0% +some of you know he proposed The Big + + + align:start position:0% +some of you know he proposed The Big +Bang Theory and very strong theoretical + + align:start position:0% +Bang Theory and very strong theoretical + + + align:start position:0% +Bang Theory and very strong theoretical +physicist and he wrote a letter to + + align:start position:0% +physicist and he wrote a letter to + + + align:start position:0% +physicist and he wrote a letter to +Watson and Crick he thought he'd figured + + align:start position:0% +Watson and Crick he thought he'd figured + + + align:start position:0% +Watson and Crick he thought he'd figured +out the basis of the of the genetic code + + align:start position:0% +out the basis of the of the genetic code + + + align:start position:0% +out the basis of the of the genetic code +and his idea was you had these sequences + + align:start position:0% +and his idea was you had these sequences + + + align:start position:0% +and his idea was you had these sequences +of AG C's and T's and so every + + align:start position:0% +of AG C's and T's and so every + + + align:start position:0% +of AG C's and T's and so every +everywhere that there was was and the + + align:start position:0% +everywhere that there was was and the + + + align:start position:0% +everywhere that there was was and the +two bases came together there were sort + + align:start position:0% +two bases came together there were sort + + + align:start position:0% +two bases came together there were sort +of like a little different shaped hole + + align:start position:0% +of like a little different shaped hole + + + align:start position:0% +of like a little different shaped hole +so his idea was the amino acids would + + align:start position:0% +so his idea was the amino acids would + + + align:start position:0% +so his idea was the amino acids would +stick into these little holes and he had + + align:start position:0% +stick into these little holes and he had + + + align:start position:0% +stick into these little holes and he had +a theory showing that you could encode + + align:start position:0% +a theory showing that you could encode + + + align:start position:0% +a theory showing that you could encode +the sequence of proteins by having the + + align:start position:0% +the sequence of proteins by having the + + + align:start position:0% +the sequence of proteins by having the +the side chains of the amino acids stick + + align:start position:0% +the side chains of the amino acids stick + + + align:start position:0% +the side chains of the amino acids stick +into these little holes along the DNA + + align:start position:0% +into these little holes along the DNA + + + align:start position:0% +into these little holes along the DNA +now that turned out to be a number of + + align:start position:0% +now that turned out to be a number of + + + align:start position:0% +now that turned out to be a number of +problems with that it didn't take into + + align:start position:0% +problems with that it didn't take into + + + align:start position:0% +problems with that it didn't take into +account the involvement of RNA which was + + align:start position:0% +account the involvement of RNA which was + + + align:start position:0% +account the involvement of RNA which was +sort of there was quite a bit of + + align:start position:0% +sort of there was quite a bit of + + + align:start position:0% +sort of there was quite a bit of +evidence for and more importantly it + + align:start position:0% +evidence for and more importantly it + + + align:start position:0% +evidence for and more importantly it +didn't take into account the the the + + align:start position:0% +didn't take into account the the the + + + align:start position:0% +didn't take into account the the the +structure of the side chains of the + + align:start position:0% +structure of the side chains of the + + + align:start position:0% +structure of the side chains of the +amino acids which you guys have been + + align:start position:0% +amino acids which you guys have been + + + align:start position:0% +amino acids which you guys have been +exposed to but it had a very profound + + align:start position:0% +exposed to but it had a very profound + + + align:start position:0% +exposed to but it had a very profound +influence on Watson and C they read this + + align:start position:0% +influence on Watson and C they read this + + + align:start position:0% +influence on Watson and C they read this +letter they immediately realized the + + align:start position:0% +letter they immediately realized the + + + align:start position:0% +letter they immediately realized the +idea was wrong they went out and had a + + align:start position:0% +idea was wrong they went out and had a + + + align:start position:0% +idea was wrong they went out and had a +lunch at a pub decided that gamow had + + align:start position:0% +lunch at a pub decided that gamow had + + + align:start position:0% +lunch at a pub decided that gamow had +had actually thought there were 25 amino + + align:start position:0% +had actually thought there were 25 amino + + + align:start position:0% +had actually thought there were 25 amino +acids but they realized some of them + + align:start position:0% +acids but they realized some of them + + + align:start position:0% +acids but they realized some of them +were just sort of special ones that were + + align:start position:0% +were just sort of special ones that were + + + align:start position:0% +were just sort of special ones that were +modified only in particular proteins and + + align:start position:0% +modified only in particular proteins and + + + align:start position:0% +modified only in particular proteins and +there were really 20 amino acids that + + align:start position:0% +there were really 20 amino acids that + + + align:start position:0% +there were really 20 amino acids that +were found universally in nature in + + align:start position:0% +were found universally in nature in + + + align:start position:0% +were found universally in nature in +amino acids and what they crick in + + align:start position:0% +amino acids and what they crick in + + + align:start position:0% +amino acids and what they crick in +particular realized was that maybe + + align:start position:0% +particular realized was that maybe + + + align:start position:0% +particular realized was that maybe +instead of having to think about protein + + align:start position:0% +instead of having to think about protein + + + align:start position:0% +instead of having to think about protein +synthesis through this very complex ex + + align:start position:0% +synthesis through this very complex ex + + + align:start position:0% +synthesis through this very complex ex +set of extracts and mixtures the + + align:start position:0% +set of extracts and mixtures the + + + align:start position:0% +set of extracts and mixtures the +biochemist was would work on that he + + align:start position:0% +biochemist was would work on that he + + + align:start position:0% +biochemist was would work on that he +could think about it at a purely + + align:start position:0% +could think about it at a purely + + + align:start position:0% +could think about it at a purely +theoretical level which basically is up + + align:start position:0% +theoretical level which basically is up + + + align:start position:0% +theoretical level which basically is up +at this kind of level that if you have a + + align:start position:0% +at this kind of level that if you have a + + + align:start position:0% +at this kind of level that if you have a +molecule that has four letters and it's + + align:start position:0% +molecule that has four letters and it's + + + align:start position:0% +molecule that has four letters and it's +going to be encoding proteins how does + + align:start position:0% +going to be encoding proteins how does + + + align:start position:0% +going to be encoding proteins how does +it do it can I work out sort of the + + align:start position:0% +it do it can I work out sort of the + + + align:start position:0% +it do it can I work out sort of the +basis or a possible theory for that + + align:start position:0% +basis or a possible theory for that + + + align:start position:0% +basis or a possible theory for that +could happen without actually knowing + + align:start position:0% +could happen without actually knowing + + + align:start position:0% +could happen without actually knowing +all of the biochemical details so Crick + + align:start position:0% +all of the biochemical details so Crick + + + align:start position:0% +all of the biochemical details so Crick +made a couple of + + align:start position:0% +made a couple of + + + align:start position:0% +made a couple of +simplifying uh + + align:start position:0% +simplifying uh + + + align:start position:0% +simplifying uh +assumptions one was that the DNA only + + align:start position:0% + + + + align:start position:0% + +determined the linear + + align:start position:0% + + + + align:start position:0% + +sequence of amino + + align:start position:0% +sequence of amino + + + align:start position:0% +sequence of amino +acids + + align:start position:0% +acids + + + align:start position:0% +acids +in + + align:start position:0% +in + + + align:start position:0% +in +protein that all this information about + + align:start position:0% +protein that all this information about + + + align:start position:0% +protein that all this information about +the three-dimensional stuff came from + + align:start position:0% +the three-dimensional stuff came from + + + align:start position:0% +the three-dimensional stuff came from +the properties of the of the uh linear + + align:start position:0% +the properties of the of the uh linear + + + align:start position:0% +the properties of the of the uh linear +sequence once it was made and I think + + align:start position:0% +sequence once it was made and I think + + + align:start position:0% +sequence once it was made and I think +you've hopefully have enough + + align:start position:0% +you've hopefully have enough + + + align:start position:0% +you've hopefully have enough +understanding of hydrophobic and other + + align:start position:0% +understanding of hydrophobic and other + + + align:start position:0% +understanding of hydrophobic and other +sorts of interactions that would cause a + + align:start position:0% +sorts of interactions that would cause a + + + align:start position:0% +sorts of interactions that would cause a +a linear sequence of amino acids to take + + align:start position:0% +a linear sequence of amino acids to take + + + align:start position:0% +a linear sequence of amino acids to take +up a particular confirmation and the + + align:start position:0% +up a particular confirmation and the + + + align:start position:0% +up a particular confirmation and the +other thing he just he uh assumption he + + align:start position:0% +other thing he just he uh assumption he + + + align:start position:0% +other thing he just he uh assumption he +made that it must be + + align:start position:0% + + + + align:start position:0% + +Universal + + align:start position:0% +Universal + + + align:start position:0% +Universal +and it would be hard to see how life + + align:start position:0% +and it would be hard to see how life + + + align:start position:0% +and it would be hard to see how life +could have started if there wasn't some + + align:start position:0% +could have started if there wasn't some + + + align:start position:0% +could have started if there wasn't some +kind of of uh code that was Universal + + align:start position:0% +kind of of uh code that was Universal + + + align:start position:0% +kind of of uh code that was Universal +between + + align:start position:0% +between + + + align:start position:0% +between +organisms and if you start from those + + align:start position:0% +organisms and if you start from those + + + align:start position:0% +organisms and if you start from those +kind of considerations then what you can + + align:start position:0% +kind of considerations then what you can + + + align:start position:0% +kind of considerations then what you can +see is you can't just have a onetoone + + align:start position:0% +see is you can't just have a onetoone + + + align:start position:0% +see is you can't just have a onetoone +correspondence between a letter in the + + align:start position:0% +correspondence between a letter in the + + + align:start position:0% +correspondence between a letter in the +MEO in the uh nucleic acid alphabet and + + align:start position:0% +MEO in the uh nucleic acid alphabet and + + + align:start position:0% +MEO in the uh nucleic acid alphabet and +a letter down here if a stood for + + align:start position:0% +a letter down here if a stood for + + + align:start position:0% +a letter down here if a stood for +veiling that would be fine but you could + + align:start position:0% +veiling that would be fine but you could + + + align:start position:0% +veiling that would be fine but you could +only have code for four me acids that + + align:start position:0% +only have code for four me acids that + + + align:start position:0% +only have code for four me acids that +way so if you had onel + + align:start position:0% + + + + align:start position:0% + +words in + + align:start position:0% +words in + + + align:start position:0% +words in +DNA there are four possibilities and so + + align:start position:0% +DNA there are four possibilities and so + + + align:start position:0% +DNA there are four possibilities and so +you could only make four if you had two + + align:start position:0% +you could only make four if you had two + + + align:start position:0% +you could only make four if you had two +two letter + + align:start position:0% + + + + align:start position:0% + +words then you'd have 16 possibilities + + align:start position:0% +words then you'd have 16 possibilities + + + align:start position:0% +words then you'd have 16 possibilities +still not enough for uh all the amino + + align:start position:0% +still not enough for uh all the amino + + + align:start position:0% +still not enough for uh all the amino +acids if you had three-letter word + + align:start position:0% + + + + align:start position:0% + +then you could do 64 and there'd be in + + align:start position:0% +then you could do 64 and there'd be in + + + align:start position:0% +then you could do 64 and there'd be in +principle that would be all you need it + + align:start position:0% +principle that would be all you need it + + + align:start position:0% +principle that would be all you need it +doesn't rule out there couldn't be five + + align:start position:0% +doesn't rule out there couldn't be five + + + align:start position:0% +doesn't rule out there couldn't be five +or six seven letter words or if you + + align:start position:0% +or six seven letter words or if you + + + align:start position:0% +or six seven letter words or if you +think about this as they were thinking + + align:start position:0% +think about this as they were thinking + + + align:start position:0% +think about this as they were thinking +about it at the time uh even if it were + + align:start position:0% +about it at the time uh even if it were + + + align:start position:0% +about it at the time uh even if it were +let's say a three-letter word is it a + + align:start position:0% +let's say a three-letter word is it a + + + align:start position:0% +let's say a three-letter word is it a +code where you have one word then the + + align:start position:0% +code where you have one word then the + + + align:start position:0% +code where you have one word then the +next word the next word or could it be + + align:start position:0% +next word the next word or could it be + + + align:start position:0% +next word the next word or could it be +an overlapping word and what about + + align:start position:0% +an overlapping word and what about + + + align:start position:0% +an overlapping word and what about +punctuation and maybe another thing you + + align:start position:0% +punctuation and maybe another thing you + + + align:start position:0% +punctuation and maybe another thing you +can see if it's agct da d da there's a + + align:start position:0% +can see if it's agct da d da there's a + + + align:start position:0% +can see if it's agct da d da there's a +frame of reference problem because if + + align:start position:0% +frame of reference problem because if + + + align:start position:0% +frame of reference problem because if +I'm going to read them in groups of + + align:start position:0% +I'm going to read them in groups of + + + align:start position:0% +I'm going to read them in groups of +three if I start here I'll get one word + + align:start position:0% +three if I start here I'll get one word + + + align:start position:0% +three if I start here I'll get one word +but if I start one letter over the next + + align:start position:0% +but if I start one letter over the next + + + align:start position:0% +but if I start one letter over the next +group of three won't be the same so + + align:start position:0% +group of three won't be the same so + + + align:start position:0% +group of three won't be the same so +somehow there would have to be uh a + + align:start position:0% +somehow there would have to be uh a + + + align:start position:0% +somehow there would have to be uh a +starting point and so these are the sort + + align:start position:0% +starting point and so these are the sort + + + align:start position:0% +starting point and so these are the sort +of considerations that they that uh they + + align:start position:0% +of considerations that they that uh they + + + align:start position:0% +of considerations that they that uh they +had to take + + align:start position:0% +had to take + + + align:start position:0% +had to take +into uh account and and in fact Watson + + align:start position:0% +into uh account and and in fact Watson + + + align:start position:0% +into uh account and and in fact Watson +and uh excuse me uh Francis Crick and + + align:start position:0% +and uh excuse me uh Francis Crick and + + + align:start position:0% +and uh excuse me uh Francis Crick and +another scientist uh um Sydney brener + + align:start position:0% +another scientist uh um Sydney brener + + + align:start position:0% +another scientist uh um Sydney brener +and some others other scientists worked + + align:start position:0% +and some others other scientists worked + + + align:start position:0% +and some others other scientists worked +out a very elegant uh genetic experiment + + align:start position:0% +out a very elegant uh genetic experiment + + + align:start position:0% +out a very elegant uh genetic experiment +that that demonstrated that it was a + + align:start position:0% +that that demonstrated that it was a + + + align:start position:0% +that that demonstrated that it was a +three-letter + + align:start position:0% +three-letter + + + align:start position:0% +three-letter +code and I don't have the um the time to + + align:start position:0% +code and I don't have the um the time to + + + align:start position:0% +code and I don't have the um the time to +go into it in this course if you take a + + align:start position:0% +go into it in this course if you take a + + + align:start position:0% +go into it in this course if you take a +genetics course it's a it's a very + + align:start position:0% +genetics course it's a it's a very + + + align:start position:0% +genetics course it's a it's a very +beautiful experiment um the principle of + + align:start position:0% +beautiful experiment um the principle of + + + align:start position:0% +beautiful experiment um the principle of +the thing which I could show you rather + + align:start position:0% +the thing which I could show you rather + + + align:start position:0% +the thing which I could show you rather +easily is if you're writing a a + + align:start position:0% +easily is if you're writing a a + + + align:start position:0% +easily is if you're writing a a +three-letter word a three thing where + + align:start position:0% +three-letter word a three thing where + + + align:start position:0% +three-letter word a three thing where +you're reading in three-letter + + align:start position:0% + + + + align:start position:0% + +words something like this the cat ran + + align:start position:0% +words something like this the cat ran + + + align:start position:0% +words something like this the cat ran +out and I don't + + align:start position:0% +out and I don't + + + align:start position:0% +out and I don't +know ate the rat or something like that + + align:start position:0% +know ate the rat or something like that + + + align:start position:0% +know ate the rat or something like that +and these were all just continuously run + + align:start position:0% +and these were all just continuously run + + + align:start position:0% +and these were all just continuously run +together not not separated out but I put + + align:start position:0% +together not not separated out but I put + + + align:start position:0% +together not not separated out but I put +them out here as you can see the + + align:start position:0% +them out here as you can see the + + + align:start position:0% +them out here as you can see the +three-letter words if you lost one + + align:start position:0% +three-letter words if you lost one + + + align:start position:0% +three-letter words if you lost one +letter then it would change to sort of + + align:start position:0% +letter then it would change to sort of + + + align:start position:0% +letter then it would change to sort of +gibberish you'd get uh stuff that looked + + align:start position:0% +gibberish you'd get uh stuff that looked + + + align:start position:0% +gibberish you'd get uh stuff that looked +like like this and if you uh put one one + + align:start position:0% +like like this and if you uh put one one + + + align:start position:0% +like like this and if you uh put one one +in you'd have the same problem but if + + align:start position:0% +in you'd have the same problem but if + + + align:start position:0% +in you'd have the same problem but if +you were to take + + align:start position:0% +you were to take + + + align:start position:0% +you were to take +out either take out three letters or put + + align:start position:0% +out either take out three letters or put + + + align:start position:0% +out either take out three letters or put +in three letters then even though + + align:start position:0% +in three letters then even though + + + align:start position:0% +in three letters then even though +there'd be a little mess in here + + align:start position:0% +there'd be a little mess in here + + + align:start position:0% +there'd be a little mess in here +somewhere say I took out two more of + + align:start position:0% +somewhere say I took out two more of + + + align:start position:0% +somewhere say I took out two more of +these what we would now from then on + + align:start position:0% +these what we would now from then on + + + align:start position:0% +these what we would now from then on +we'd have but the rest of + + align:start position:0% + + + + align:start position:0% + +it would now makes sense again and they + + align:start position:0% +it would now makes sense again and they + + + align:start position:0% +it would now makes sense again and they +did this sort of experiment genetically + + align:start position:0% +did this sort of experiment genetically + + + align:start position:0% +did this sort of experiment genetically +they managed to figure out there were + + align:start position:0% +they managed to figure out there were + + + align:start position:0% +they managed to figure out there were +two kinds of mutations they could get in + + align:start position:0% +two kinds of mutations they could get in + + + align:start position:0% +two kinds of mutations they could get in +a particular way some were putting in a + + align:start position:0% +a particular way some were putting in a + + + align:start position:0% +a particular way some were putting in a +letter some were taking out a letter and + + align:start position:0% +letter some were taking out a letter and + + + align:start position:0% +letter some were taking out a letter and +they didn't know at the time whether + + align:start position:0% +they didn't know at the time whether + + + align:start position:0% +they didn't know at the time whether +they're adding or deleting but they + + align:start position:0% +they're adding or deleting but they + + + align:start position:0% +they're adding or deleting but they +could tell they were in the opposite + + align:start position:0% +could tell they were in the opposite + + + align:start position:0% +could tell they were in the opposite +directions and then they found if they + + align:start position:0% +directions and then they found if they + + + align:start position:0% +directions and then they found if they +took three of one class like three that + + align:start position:0% +took three of one class like three that + + + align:start position:0% +took three of one class like three that +would delete a letter and put them all + + align:start position:0% +would delete a letter and put them all + + + align:start position:0% +would delete a letter and put them all +together then things would more or less + + align:start position:0% +together then things would more or less + + + align:start position:0% +together then things would more or less +work or if they put three that stuck in + + align:start position:0% +work or if they put three that stuck in + + + align:start position:0% +work or if they put three that stuck in +an extra letter then everything would + + align:start position:0% +an extra letter then everything would + + + align:start position:0% +an extra letter then everything would +more or less work so there was a genetic + + align:start position:0% +more or less work so there was a genetic + + + align:start position:0% +more or less work so there was a genetic +proof of the uh three-letter part of the + + align:start position:0% +proof of the uh three-letter part of the + + + align:start position:0% +proof of the uh three-letter part of the +code before it was figured out exactly + + align:start position:0% +code before it was figured out exactly + + + align:start position:0% +code before it was figured out exactly +uh how the code + + align:start position:0% +uh how the code + + + align:start position:0% +uh how the code +itself itself worked and so going from + + align:start position:0% +itself itself worked and so going from + + + align:start position:0% +itself itself worked and so going from +this um sort of + + align:start position:0% +this um sort of + + + align:start position:0% +this um sort of +theoretical uh insight into the the code + + align:start position:0% +theoretical uh insight into the the code + + + align:start position:0% +theoretical uh insight into the the code +to actually figuring out how proteins + + align:start position:0% +to actually figuring out how proteins + + + align:start position:0% +to actually figuring out how proteins +were made uh was was still was still + + align:start position:0% +were made uh was was still was still + + + align:start position:0% +were made uh was was still was still +quite a lot of stuff that had to to + + align:start position:0% +quite a lot of stuff that had to to + + + align:start position:0% +quite a lot of stuff that had to to +happen and one was + + align:start position:0% +happen and one was + + + align:start position:0% +happen and one was +the the concept + + align:start position:0% + + + + align:start position:0% + +of messenger RNA as I said there had + + align:start position:0% +of messenger RNA as I said there had + + + align:start position:0% +of messenger RNA as I said there had +been quite a lot of evidence that RNA + + align:start position:0% +been quite a lot of evidence that RNA + + + align:start position:0% +been quite a lot of evidence that RNA +was somehow involved in protein + + align:start position:0% +was somehow involved in protein + + + align:start position:0% +was somehow involved in protein +synthesis because cells that made a lot + + align:start position:0% +synthesis because cells that made a lot + + + align:start position:0% +synthesis because cells that made a lot +of protein made a lot of RNA and it + + align:start position:0% +of protein made a lot of RNA and it + + + align:start position:0% +of protein made a lot of RNA and it +seemed to be um in the right sort of + + align:start position:0% +seemed to be um in the right sort of + + + align:start position:0% +seemed to be um in the right sort of +place in the in the cell uh for the + + align:start position:0% +place in the in the cell uh for the + + + align:start position:0% +place in the in the cell uh for the +proteins to be made so the idea emerged + + align:start position:0% +proteins to be made so the idea emerged + + + align:start position:0% +proteins to be made so the idea emerged +that RNA was somehow a carrier of + + align:start position:0% +that RNA was somehow a carrier of + + + align:start position:0% +that RNA was somehow a carrier of +information from the DNA + + align:start position:0% +information from the DNA + + + align:start position:0% +information from the DNA +to the cytoplasm so it would uh carry uh + + align:start position:0% +to the cytoplasm so it would uh carry uh + + + align:start position:0% +to the cytoplasm so it would uh carry uh +could serve as a template for making + + align:start position:0% +could serve as a template for making + + + align:start position:0% +could serve as a template for making +proteins + + align:start position:0% + + + + align:start position:0% + +so so the idea was to cop that the cell + + align:start position:0% +so so the idea was to cop that the cell + + + align:start position:0% +so so the idea was to cop that the cell +copied the sequence of a + + align:start position:0% + + + + align:start position:0% + +portion of the DNA and we'd probably + + align:start position:0% +portion of the DNA and we'd probably + + + align:start position:0% +portion of the DNA and we'd probably +think of this as a gene right now + + align:start position:0% + + + + align:start position:0% + +um into RNA and the + + align:start position:0% +um into RNA and the + + + align:start position:0% +um into RNA and the +RNA would go into the cytoplasm that's + + align:start position:0% +RNA would go into the cytoplasm that's + + + align:start position:0% +RNA would go into the cytoplasm that's +the part outside the + + align:start position:0% +the part outside the + + + align:start position:0% +the part outside the +nucleus and then it would + + align:start position:0% +nucleus and then it would + + + align:start position:0% +nucleus and then it would +serve as a + + align:start position:0% + + + + align:start position:0% + +template for protein + + align:start position:0% +template for protein + + + align:start position:0% +template for protein +synthesis because of this + + align:start position:0% +synthesis because of this + + + align:start position:0% +synthesis because of this +this thought that if you had a cell like + + align:start position:0% +this thought that if you had a cell like + + + align:start position:0% +this thought that if you had a cell like +this with the + + align:start position:0% + + + + align:start position:0% + +nucleus and the DNA and here that if a + + align:start position:0% +nucleus and the DNA and here that if a + + + align:start position:0% +nucleus and the DNA and here that if a +piece of + + align:start position:0% +piece of + + + align:start position:0% +piece of +RNA were to go out into the cytoplasm + + align:start position:0% +RNA were to go out into the cytoplasm + + + align:start position:0% +RNA were to go out into the cytoplasm +and have those properties it would be + + align:start position:0% +and have those properties it would be + + + align:start position:0% +and have those properties it would be +functioning more or less as a messenger + + align:start position:0% +functioning more or less as a messenger + + + align:start position:0% +functioning more or less as a messenger +that would be carrying the genetic + + align:start position:0% +that would be carrying the genetic + + + align:start position:0% +that would be carrying the genetic +information from inside the nucleus out + + align:start position:0% +information from inside the nucleus out + + + align:start position:0% +information from inside the nucleus out +into the cytoplasm and so the term uh + + align:start position:0% +into the cytoplasm and so the term uh + + + align:start position:0% +into the cytoplasm and so the term uh +began to be used of a a messenger RNA + + align:start position:0% +began to be used of a a messenger RNA + + + align:start position:0% +began to be used of a a messenger RNA +and and so over + + align:start position:0% + + + + align:start position:0% + +here I'll put an MR RNA to to indicate + + align:start position:0% +here I'll put an MR RNA to to indicate + + + align:start position:0% +here I'll put an MR RNA to to indicate +uh that now one thing you can also see + + align:start position:0% +uh that now one thing you can also see + + + align:start position:0% +uh that now one thing you can also see +is we've talked about the structure of + + align:start position:0% +is we've talked about the structure of + + + align:start position:0% +is we've talked about the structure of +of + + align:start position:0% +of + + + align:start position:0% +of +um of DNA and + + align:start position:0% + + + + align:start position:0% + +RNA and it's essentially the same with + + align:start position:0% +RNA and it's essentially the same with + + + align:start position:0% +RNA and it's essentially the same with +one this is the nucleotide which is the + + align:start position:0% +one this is the nucleotide which is the + + + align:start position:0% +one this is the nucleotide which is the +fundamental uh building + + align:start position:0% +fundamental uh building + + + align:start position:0% +fundamental uh building +block of DNA and if you recall in DNA + + align:start position:0% +block of DNA and if you recall in DNA + + + align:start position:0% +block of DNA and if you recall in DNA +there's a hydroxy excuse me a hydrogen + + align:start position:0% +there's a hydroxy excuse me a hydrogen + + + align:start position:0% +there's a hydroxy excuse me a hydrogen +there but in + + align:start position:0% +there but in + + + align:start position:0% +there but in +RNA there is this extra uh + + align:start position:0% +RNA there is this extra uh + + + align:start position:0% +RNA there is this extra uh +hydroxy this is one one prime two Prime + + align:start position:0% +hydroxy this is one one prime two Prime + + + align:start position:0% +hydroxy this is one one prime two Prime +3 Prime 4 Prime excuse me one let's just + + align:start position:0% +3 Prime 4 Prime excuse me one let's just + + + align:start position:0% +3 Prime 4 Prime excuse me one let's just +leave it like this for the moment 1 2 3 + + align:start position:0% +leave it like this for the moment 1 2 3 + + + align:start position:0% +leave it like this for the moment 1 2 3 +four five and so this uh the um DNA as + + align:start position:0% +four five and so this uh the um DNA as + + + align:start position:0% +four five and so this uh the um DNA as +we heard was um deoxy ribon acid because + + align:start position:0% +we heard was um deoxy ribon acid because + + + align:start position:0% +we heard was um deoxy ribon acid because +it's missing this but other than that uh + + align:start position:0% +it's missing this but other than that uh + + + align:start position:0% +it's missing this but other than that uh +the backbones are are are similar so and + + align:start position:0% +the backbones are are are similar so and + + + align:start position:0% +the backbones are are are similar so and +the the letters are almost the same the + + align:start position:0% +the the letters are almost the same the + + + align:start position:0% +the the letters are almost the same the +a the G and the C are exactly the same + + align:start position:0% +a the G and the C are exactly the same + + + align:start position:0% +a the G and the C are exactly the same +bases in DNA and RNA the only difference + + align:start position:0% +bases in DNA and RNA the only difference + + + align:start position:0% +bases in DNA and RNA the only difference +is with the T and the and the + + align:start position:0% + + + + align:start position:0% + +uracil so this + + align:start position:0% +uracil so this + + + align:start position:0% +uracil so this +is + + align:start position:0% +is + + + align:start position:0% +is +this is thyine which is found in + + align:start position:0% +this is thyine which is found in + + + align:start position:0% +this is thyine which is found in +DNA and this is our this is + + align:start position:0% + + + + align:start position:0% + +uracil which is found + + align:start position:0% + + + + align:start position:0% + +in uh found in RNA so the base pairing + + align:start position:0% +in uh found in RNA so the base pairing + + + align:start position:0% +in uh found in RNA so the base pairing +is over on this part of the molecule so + + align:start position:0% +is over on this part of the molecule so + + + align:start position:0% +is over on this part of the molecule so +whether or not you have a methyl group + + align:start position:0% +whether or not you have a methyl group + + + align:start position:0% +whether or not you have a methyl group +doesn't really change the base pairing + + align:start position:0% +doesn't really change the base pairing + + + align:start position:0% +doesn't really change the base pairing +and so this process of copying + + align:start position:0% +and so this process of copying + + + align:start position:0% +and so this process of copying +information in DNA uh to uh me to + + align:start position:0% +information in DNA uh to uh me to + + + align:start position:0% +information in DNA uh to uh me to +information that's in RNA was seen as + + align:start position:0% +information that's in RNA was seen as + + + align:start position:0% +information that's in RNA was seen as +it's essentially the same kind of + + align:start position:0% +it's essentially the same kind of + + + align:start position:0% +it's essentially the same kind of +language but it's just sort of like + + align:start position:0% +language but it's just sort of like + + + align:start position:0% +language but it's just sort of like +taking somebody's word processor file + + align:start position:0% +taking somebody's word processor file + + + align:start position:0% +taking somebody's word processor file +and writing out long hand uh you'd be + + align:start position:0% +and writing out long hand uh you'd be + + + align:start position:0% +and writing out long hand uh you'd be +transcribing the information + + align:start position:0% +transcribing the information + + + align:start position:0% +transcribing the information +but it would be the same essentially the + + align:start position:0% +but it would be the same essentially the + + + align:start position:0% +but it would be the same essentially the +same kind of information in essentially + + align:start position:0% +same kind of information in essentially + + + align:start position:0% +same kind of information in essentially +the same the same form so this is known + + align:start position:0% +the same the same form so this is known + + + align:start position:0% +the same the same form so this is known +as + + align:start position:0% + + + + align:start position:0% + +transcription I'll take just one very + + align:start position:0% +transcription I'll take just one very + + + align:start position:0% +transcription I'll take just one very +brief thing some of you may wonder why + + align:start position:0% +brief thing some of you may wonder why + + + align:start position:0% +brief thing some of you may wonder why +did nature do it this way Why didn't it + + align:start position:0% +did nature do it this way Why didn't it + + + align:start position:0% +did nature do it this way Why didn't it +just use + + align:start position:0% +just use + + + align:start position:0% +just use +uracil in DNA so as a very brief aside + + align:start position:0% +uracil in DNA so as a very brief aside + + + align:start position:0% +uracil in DNA so as a very brief aside +uh there we I think we understand + + align:start position:0% +uh there we I think we understand + + + align:start position:0% +uh there we I think we understand +pretty much what why it does it and that + + align:start position:0% +pretty much what why it does it and that + + + align:start position:0% +pretty much what why it does it and that +is + + align:start position:0% +is + + + align:start position:0% +is +citadine has this + + align:start position:0% + + + + align:start position:0% + +um structure this is so this is C which + + align:start position:0% +um structure this is so this is C which + + + align:start position:0% +um structure this is so this is C which +is found in DNA but it undergoes uh all + + align:start position:0% +is found in DNA but it undergoes uh all + + + align:start position:0% +is found in DNA but it undergoes uh all +all of your um DNA is is a chemical and + + align:start position:0% +all of your um DNA is is a chemical and + + + align:start position:0% +all of your um DNA is is a chemical and +it's it's able to undergo spontaneous + + align:start position:0% +it's it's able to undergo spontaneous + + + align:start position:0% +it's it's able to undergo spontaneous +kinds of damage uh in fact we have in a + + align:start position:0% +kinds of damage uh in fact we have in a + + + align:start position:0% +kinds of damage uh in fact we have in a +every one of our cells uh every day + + align:start position:0% +every one of our cells uh every day + + + align:start position:0% +every one of our cells uh every day +10,000 times in any given cell a base + + align:start position:0% +10,000 times in any given cell a base + + + align:start position:0% +10,000 times in any given cell a base +falls off totally just leaving a the + + align:start position:0% +falls off totally just leaving a the + + + align:start position:0% +falls off totally just leaving a the +deoxy ribos sitting there and the cells + + align:start position:0% +deoxy ribos sitting there and the cells + + + align:start position:0% +deoxy ribos sitting there and the cells +have to fix it up and we have DNA repair + + align:start position:0% +have to fix it up and we have DNA repair + + + align:start position:0% +have to fix it up and we have DNA repair +systems that do that but another very + + align:start position:0% +systems that do that but another very + + + align:start position:0% +systems that do that but another very +common kind of of thing that that + + align:start position:0% +common kind of of thing that that + + + align:start position:0% +common kind of of thing that that +happens is that uh this nh2 group + + align:start position:0% +happens is that uh this nh2 group + + + align:start position:0% +happens is that uh this nh2 group +deaminates + + align:start position:0% +deaminates + + + align:start position:0% +deaminates +and if you do that if if a c happens to + + align:start position:0% +and if you do that if if a c happens to + + + align:start position:0% +and if you do that if if a c happens to +deaminate in DNA it gives you a + + align:start position:0% +deaminate in DNA it gives you a + + + align:start position:0% +deaminate in DNA it gives you a +uracil and if that ever happens the cell + + align:start position:0% +uracil and if that ever happens the cell + + + align:start position:0% +uracil and if that ever happens the cell +is actually able to tell that the uh + + align:start position:0% +is actually able to tell that the uh + + + align:start position:0% +is actually able to tell that the uh +that something went wrong because urell + + align:start position:0% +that something went wrong because urell + + + align:start position:0% +that something went wrong because urell +is not supposed to be in DNA and there + + align:start position:0% +is not supposed to be in DNA and there + + + align:start position:0% +is not supposed to be in DNA and there +are repair systems that constantly scan + + align:start position:0% +are repair systems that constantly scan + + + align:start position:0% +are repair systems that constantly scan +the DNA and take out take out any + + align:start position:0% +the DNA and take out take out any + + + align:start position:0% +the DNA and take out take out any +uracils that that are in + + align:start position:0% +uracils that that are in + + + align:start position:0% +uracils that that are in +there and the reason that if if uh it + + align:start position:0% +there and the reason that if if uh it + + + align:start position:0% +there and the reason that if if uh it +actually used thyine instead of using + + align:start position:0% +actually used thyine instead of using + + + align:start position:0% +actually used thyine instead of using +thyine it used uracil then the cell + + align:start position:0% +thyine it used uracil then the cell + + + align:start position:0% +thyine it used uracil then the cell +wouldn't know whether the osell got + + align:start position:0% +wouldn't know whether the osell got + + + align:start position:0% +wouldn't know whether the osell got +there because it was supposed to be + + align:start position:0% +there because it was supposed to be + + + align:start position:0% +there because it was supposed to be +there as part of the sequence or whether + + align:start position:0% +there as part of the sequence or whether + + + align:start position:0% +there as part of the sequence or whether +it had Arisen by uh deamination of a of + + align:start position:0% +it had Arisen by uh deamination of a of + + + align:start position:0% +it had Arisen by uh deamination of a of +a citadine it's a minor point but there + + align:start position:0% +a citadine it's a minor point but there + + + align:start position:0% +a citadine it's a minor point but there +is I think we do have an understanding + + align:start position:0% +is I think we do have an understanding + + + align:start position:0% +is I think we do have an understanding +as to why there's thyine in DNA and + + align:start position:0% +as to why there's thyine in DNA and + + + align:start position:0% +as to why there's thyine in DNA and +uracil in in RNA this isn't isn't such a + + align:start position:0% +uracil in in RNA this isn't isn't such a + + + align:start position:0% +uracil in in RNA this isn't isn't such a +worry in uh in + + align:start position:0% +worry in uh in + + + align:start position:0% +worry in uh in +RNA okay but anyway um so there's still + + align:start position:0% +RNA okay but anyway um so there's still + + + align:start position:0% +RNA okay but anyway um so there's still +a really big problem here though that + + align:start position:0% +a really big problem here though that + + + align:start position:0% +a really big problem here though that +that Watson and Crick and others were + + align:start position:0% +that Watson and Crick and others were + + + align:start position:0% +that Watson and Crick and others were +grappling with and it has to do as I say + + align:start position:0% +grappling with and it has to do as I say + + + align:start position:0% +grappling with and it has to do as I say +with this fact that the information up + + align:start position:0% +with this fact that the information up + + + align:start position:0% +with this fact that the information up +here is uh the first in DNA and RNA it's + + align:start position:0% +here is uh the first in DNA and RNA it's + + + align:start position:0% +here is uh the first in DNA and RNA it's +written as a sequence of uh of letters + + align:start position:0% +written as a sequence of uh of letters + + + align:start position:0% +written as a sequence of uh of letters +if you will chemical letters but there + + align:start position:0% +if you will chemical letters but there + + + align:start position:0% +if you will chemical letters but there +are only four letters in the DNA + + align:start position:0% +are only four letters in the DNA + + + align:start position:0% +are only four letters in the DNA +alphabet and essentially the same four + + align:start position:0% +alphabet and essentially the same four + + + align:start position:0% +alphabet and essentially the same four +letters in the RNA alphabet however the + + align:start position:0% +letters in the RNA alphabet however the + + + align:start position:0% +letters in the RNA alphabet however the +protein language has got a totally + + align:start position:0% +protein language has got a totally + + + align:start position:0% +protein language has got a totally +different alphabet so uh we it's somehow + + align:start position:0% +different alphabet so uh we it's somehow + + + align:start position:0% +different alphabet so uh we it's somehow +like sort of translating now from + + align:start position:0% +like sort of translating now from + + + align:start position:0% +like sort of translating now from +English to Japanese or something like + + align:start position:0% +English to Japanese or something like + + + align:start position:0% +English to Japanese or something like +that some really fundamental change had + + align:start position:0% +that some really fundamental change had + + + align:start position:0% +that some really fundamental change had +to happen because it was a real + + align:start position:0% +to happen because it was a real + + + align:start position:0% +to happen because it was a real +conversion from one kind of language to + + align:start position:0% +conversion from one kind of language to + + + align:start position:0% +conversion from one kind of language to +another and so this process is known as + + align:start position:0% +another and so this process is known as + + + align:start position:0% +another and so this process is known as +as translation that's going from + + align:start position:0% +as translation that's going from + + + align:start position:0% +as translation that's going from +information that's written using a + + align:start position:0% +information that's written using a + + + align:start position:0% +information that's written using a +four-letter nucleic acid uh alphabet to + + align:start position:0% +four-letter nucleic acid uh alphabet to + + + align:start position:0% +four-letter nucleic acid uh alphabet to +information that's written using a 20l + + align:start position:0% +information that's written using a 20l + + + align:start position:0% +information that's written using a 20l +uh amino acid alphabet and uh Crick on + + align:start position:0% +uh amino acid alphabet and uh Crick on + + + align:start position:0% +uh amino acid alphabet and uh Crick on +Purely theoretical grounds figured well + + align:start position:0% +Purely theoretical grounds figured well + + + align:start position:0% +Purely theoretical grounds figured well +if you're going from one language to + + align:start position:0% +if you're going from one language to + + + align:start position:0% +if you're going from one language to +another what do you need you need a + + align:start position:0% +another what do you need you need a + + + align:start position:0% +another what do you need you need a +translator and what's a translator a + + align:start position:0% +translator and what's a translator a + + + align:start position:0% +translator and what's a translator a +translator is someone who speaks both + + align:start position:0% +translator is someone who speaks both + + + align:start position:0% +translator is someone who speaks both +languages so his idea was that if there + + align:start position:0% + + + + align:start position:0% + +was I'm going to just separate out let's + + align:start position:0% +was I'm going to just separate out let's + + + align:start position:0% +was I'm going to just separate out let's +say this is the messenger RNA and I just + + align:start position:0% +say this is the messenger RNA and I just + + + align:start position:0% +say this is the messenger RNA and I just +for for um Clarity here have spaced out + + align:start position:0% +for for um Clarity here have spaced out + + + align:start position:0% +for for um Clarity here have spaced out +the three-letter words so we can see + + align:start position:0% +the three-letter words so we can see + + + align:start position:0% +the three-letter words so we can see +them these would be three like g a c or + + align:start position:0% +them these would be three like g a c or + + + align:start position:0% +them these would be three like g a c or +something like that in the uh in the RNA + + align:start position:0% +something like that in the uh in the RNA + + + align:start position:0% +something like that in the uh in the RNA +that there would be some kind of + + align:start position:0% +that there would be some kind of + + + align:start position:0% +that there would be some kind of +translator and his idea was that it + + align:start position:0% +translator and his idea was that it + + + align:start position:0% +translator and his idea was that it +would be something that had a particular + + align:start position:0% +would be something that had a particular + + + align:start position:0% +would be something that had a particular +amino acid at one end and it had the + + align:start position:0% +amino acid at one end and it had the + + + align:start position:0% +amino acid at one end and it had the +complimentary nucleotides at the other + + align:start position:0% +complimentary nucleotides at the other + + + align:start position:0% +complimentary nucleotides at the other +end so it could if you will read the + + align:start position:0% +end so it could if you will read the + + + align:start position:0% +end so it could if you will read the +genetic code that was written in the in + + align:start position:0% +genetic code that was written in the in + + + align:start position:0% +genetic code that was written in the in +the r using the the nucleic acid uh + + align:start position:0% +the r using the the nucleic acid uh + + + align:start position:0% +the r using the the nucleic acid uh +alphabet but it would also be speaking + + align:start position:0% +alphabet but it would also be speaking + + + align:start position:0% +alphabet but it would also be speaking +the amino acid uh language got the idea + + align:start position:0% +the amino acid uh language got the idea + + + align:start position:0% +the amino acid uh language got the idea +so this is this the idea was that this + + align:start position:0% +so this is this the idea was that this + + + align:start position:0% +so this is this the idea was that this +would be he they used the words adapter + + align:start position:0% +would be he they used the words adapter + + + align:start position:0% +would be he they used the words adapter +or a + + align:start position:0% + + + + align:start position:0% + +translator so that was on basically + + align:start position:0% +translator so that was on basically + + + align:start position:0% +translator so that was on basically +theoretical grounds that if you had to + + align:start position:0% +theoretical grounds that if you had to + + + align:start position:0% +theoretical grounds that if you had to +go from a four-letter language to a + + align:start position:0% +go from a four-letter language to a + + + align:start position:0% +go from a four-letter language to a +20-letter language you needed some kind + + align:start position:0% +20-letter language you needed some kind + + + align:start position:0% +20-letter language you needed some kind +of translator or adapter now at that + + align:start position:0% +of translator or adapter now at that + + + align:start position:0% +of translator or adapter now at that +same time that these considerations are + + align:start position:0% +same time that these considerations are + + + align:start position:0% +same time that these considerations are +going on biochemist began to find a + + align:start position:0% +going on biochemist began to find a + + + align:start position:0% +going on biochemist began to find a +class of small uh + + align:start position:0% + + + + align:start position:0% + +rnas that had an amino + + align:start position:0% + + + + align:start position:0% + +acid + + align:start position:0% + + + + align:start position:0% + +attached and so there were entities that + + align:start position:0% +attached and so there were entities that + + + align:start position:0% +attached and so there were entities that +had just the sort of properties that + + align:start position:0% +had just the sort of properties that + + + align:start position:0% +had just the sort of properties that +that cricet envisioned you need from + + align:start position:0% +that cricet envisioned you need from + + + align:start position:0% +that cricet envisioned you need from +theoretical uh considerations these were + + align:start position:0% +theoretical uh considerations these were + + + align:start position:0% +theoretical uh considerations these were +given the name + + align:start position:0% +given the name + + + align:start position:0% +given the name +transfer + + align:start position:0% + + + + align:start position:0% + +rnas or trnas as they're usually + + align:start position:0% +rnas or trnas as they're usually + + + align:start position:0% +rnas or trnas as they're usually +referred to uh now and I've told you + + align:start position:0% +referred to uh now and I've told you + + + align:start position:0% +referred to uh now and I've told you +that RNA a uh has since it's got nucleic + + align:start position:0% +that RNA a uh has since it's got nucleic + + + align:start position:0% +that RNA a uh has since it's got nucleic +acid bases if you have a single strand + + align:start position:0% +acid bases if you have a single strand + + + align:start position:0% +acid bases if you have a single strand +of of of uh either an RNA or a DNA and + + align:start position:0% +of of of uh either an RNA or a DNA and + + + align:start position:0% +of of of uh either an RNA or a DNA and +you don't have a complimentary double + + align:start position:0% +you don't have a complimentary double + + + align:start position:0% +you don't have a complimentary double +strand then if there are complimentary + + align:start position:0% +strand then if there are complimentary + + + align:start position:0% +strand then if there are complimentary +sequences they can come together and uh + + align:start position:0% +sequences they can come together and uh + + + align:start position:0% +sequences they can come together and uh +and pair just the same way that + + align:start position:0% +and pair just the same way that + + + align:start position:0% +and pair just the same way that +complimentary sequences can come + + align:start position:0% +complimentary sequences can come + + + align:start position:0% +complimentary sequences can come +together in in uh in DNA and in the case + + align:start position:0% +together in in uh in DNA and in the case + + + align:start position:0% +together in in uh in DNA and in the case +of trnas once we once the sequence of + + align:start position:0% +of trnas once we once the sequence of + + + align:start position:0% +of trnas once we once the sequence of +these were determined they um + + align:start position:0% + + + + align:start position:0% + +oops have to here we go um they would + + align:start position:0% +oops have to here we go um they would + + + align:start position:0% +oops have to here we go um they would +they Fold It Up in into a Cloverleaf + + align:start position:0% +they Fold It Up in into a Cloverleaf + + + align:start position:0% +they Fold It Up in into a Cloverleaf +shape and the amino acid is attached up + + align:start position:0% +shape and the amino acid is attached up + + + align:start position:0% +shape and the amino acid is attached up +at the three prime end of the chain up + + align:start position:0% +at the three prime end of the chain up + + + align:start position:0% +at the three prime end of the chain up +here what's known as the acceptor part + + align:start position:0% +here what's known as the acceptor part + + + align:start position:0% +here what's known as the acceptor part +of the molecule and down here is so + + align:start position:0% +of the molecule and down here is so + + + align:start position:0% +of the molecule and down here is so +that's that corresponds to this part up + + align:start position:0% +that's that corresponds to this part up + + + align:start position:0% +that's that corresponds to this part up +here and here are here is what's known + + align:start position:0% +here and here are here is what's known + + + align:start position:0% +here and here are here is what's known +as + + align:start position:0% +as + + + align:start position:0% +as +the + + align:start position:0% +the + + + align:start position:0% +the +anticodon the each of these three-letter + + align:start position:0% + + + + align:start position:0% + +words and nucleic acid language is G is + + align:start position:0% +words and nucleic acid language is G is + + + align:start position:0% +words and nucleic acid language is G is +called + + align:start position:0% +called + + + align:start position:0% +called +codon and so something that had a + + align:start position:0% +codon and so something that had a + + + align:start position:0% +codon and so something that had a +complementary sequence to a codon was + + align:start position:0% +complementary sequence to a codon was + + + align:start position:0% +complementary sequence to a codon was +called an anticodon so if it's um g g G + + align:start position:0% +called an anticodon so if it's um g g G + + + align:start position:0% +called an anticodon so if it's um g g G +is the codon then + + align:start position:0% +is the codon then + + + align:start position:0% +is the codon then +CCC would be the would be the uh + + align:start position:0% +CCC would be the would be the uh + + + align:start position:0% +CCC would be the would be the uh +anti-codon now this is just a schematic + + align:start position:0% +anti-codon now this is just a schematic + + + align:start position:0% +anti-codon now this is just a schematic +as you can see it shows where the um uh + + align:start position:0% +as you can see it shows where the um uh + + + align:start position:0% +as you can see it shows where the um uh +where the + + align:start position:0% +where the + + + align:start position:0% +where the +um uh hydrogen bonds are that form the + + align:start position:0% +um uh hydrogen bonds are that form the + + + align:start position:0% +um uh hydrogen bonds are that form the +stuff when the crystal structures were + + align:start position:0% +stuff when the crystal structures were + + + align:start position:0% +stuff when the crystal structures were +done first crystal structure of TRNA was + + align:start position:0% +done first crystal structure of TRNA was + + + align:start position:0% +done first crystal structure of TRNA was +actually done by Alex Rich who's in the + + align:start position:0% +actually done by Alex Rich who's in the + + + align:start position:0% +actually done by Alex Rich who's in the +biology department at MIT and he was in + + align:start position:0% +biology department at MIT and he was in + + + align:start position:0% +biology department at MIT and he was in +this picture I showed you talking to to + + align:start position:0% +this picture I showed you talking to to + + + align:start position:0% +this picture I showed you talking to to +Matt mes + + align:start position:0% +Matt mes + + + align:start position:0% +Matt mes +and we although we can't see this + + align:start position:0% +and we although we can't see this + + + align:start position:0% +and we although we can't see this +terribly well maybe you could hit the + + align:start position:0% +terribly well maybe you could hit the + + + align:start position:0% +terribly well maybe you could hit the +lights there um the crystal structure + + align:start position:0% +lights there um the crystal structure + + + align:start position:0% +lights there um the crystal structure +showed that that the the molecule had a + + align:start position:0% +showed that that the the molecule had a + + + align:start position:0% +showed that that the the molecule had a +didn't look like a clover leaf as in + + align:start position:0% +didn't look like a clover leaf as in + + + align:start position:0% +didn't look like a clover leaf as in +there it had more this shape and I'll + + align:start position:0% +there it had more this shape and I'll + + + align:start position:0% +there it had more this shape and I'll +show you this more clearly in this + + align:start position:0% +show you this more clearly in this + + + align:start position:0% +show you this more clearly in this +picture I showed you this little part of + + align:start position:0% +picture I showed you this little part of + + + align:start position:0% +picture I showed you this little part of +the of the thing when I was showing you + + align:start position:0% +the of the thing when I was showing you + + + align:start position:0% +the of the thing when I was showing you +how an RNA could form up could form + + align:start position:0% +how an RNA could form up could form + + + align:start position:0% +how an RNA could form up could form +where for example if you copy us the the + + align:start position:0% +where for example if you copy us the the + + + align:start position:0% +where for example if you copy us the the +gene encoding and TRNA and for example + + align:start position:0% +gene encoding and TRNA and for example + + + align:start position:0% +gene encoding and TRNA and for example +the the green SE sequence here in green + + align:start position:0% +the the green SE sequence here in green + + + align:start position:0% +the the green SE sequence here in green +is complimentary to the sequence here or + + align:start position:0% +is complimentary to the sequence here or + + + align:start position:0% +is complimentary to the sequence here or +the sequence here in in sort of blue or + + align:start position:0% +the sequence here in in sort of blue or + + + align:start position:0% +the sequence here in in sort of blue or +purple is complimentary to the sequence + + align:start position:0% +purple is complimentary to the sequence + + + align:start position:0% +purple is complimentary to the sequence +here that what can happen then if you + + align:start position:0% +here that what can happen then if you + + + align:start position:0% +here that what can happen then if you +allow a single strand uh RNA like this + + align:start position:0% +allow a single strand uh RNA like this + + + align:start position:0% +allow a single strand uh RNA like this +to fold up ther thermodynamically it + + align:start position:0% +to fold up ther thermodynamically it + + + align:start position:0% +to fold up ther thermodynamically it +will then go to the lower energy state + + align:start position:0% +will then go to the lower energy state + + + align:start position:0% +will then go to the lower energy state +which is involves being able to make + + align:start position:0% +which is involves being able to make + + + align:start position:0% +which is involves being able to make +these hydrogen bonds and I think you can + + align:start position:0% +these hydrogen bonds and I think you can + + + align:start position:0% +these hydrogen bonds and I think you can +sort of see the Clover Leaf here's one + + align:start position:0% +sort of see the Clover Leaf here's one + + + align:start position:0% +sort of see the Clover Leaf here's one +of the leaves the other's down here and + + align:start position:0% +of the leaves the other's down here and + + + align:start position:0% +of the leaves the other's down here and +the others it's a little bit distorted + + align:start position:0% +the others it's a little bit distorted + + + align:start position:0% +the others it's a little bit distorted +here and the reason is cuz I'm going to + + align:start position:0% +here and the reason is cuz I'm going to + + + align:start position:0% +here and the reason is cuz I'm going to +continue now to show you how this + + align:start position:0% +continue now to show you how this + + + align:start position:0% +continue now to show you how this +structure once you get to the Clover + + align:start position:0% +structure once you get to the Clover + + + align:start position:0% +structure once you get to the Clover +Leaf then it folds + + align:start position:0% +Leaf then it folds + + + align:start position:0% +Leaf then it folds +up to make other kinds of interactions + + align:start position:0% +up to make other kinds of interactions + + + align:start position:0% +up to make other kinds of interactions +and it takes that shape with the TR + + align:start position:0% +and it takes that shape with the TR + + + align:start position:0% +and it takes that shape with the TR +going on at this end and the anticodon + + align:start position:0% +going on at this end and the anticodon + + + align:start position:0% +going on at this end and the anticodon +being down here and what's happening now + + align:start position:0% +being down here and what's happening now + + + align:start position:0% +being down here and what's happening now +they've morphed on the Vandal surfaces + + align:start position:0% +they've morphed on the Vandal surfaces + + + align:start position:0% +they've morphed on the Vandal surfaces +so you can see what this would look like + + align:start position:0% +so you can see what this would look like + + + align:start position:0% +so you can see what this would look like +three-dimensional shape the TR the the + + align:start position:0% +three-dimensional shape the TR the the + + + align:start position:0% +three-dimensional shape the TR the the +amino acid would be attached at that end + + align:start position:0% +amino acid would be attached at that end + + + align:start position:0% +amino acid would be attached at that end +and there there is the anti-codon that + + align:start position:0% +and there there is the anti-codon that + + + align:start position:0% +and there there is the anti-codon that +would be able to recognize the codon in + + align:start position:0% +would be able to recognize the codon in + + + align:start position:0% +would be able to recognize the codon in +the in the RNA I mean it the physical + + align:start position:0% +the in the RNA I mean it the physical + + + align:start position:0% +the in the RNA I mean it the physical +reality is pretty close to this + + align:start position:0% +reality is pretty close to this + + + align:start position:0% +reality is pretty close to this +simple uh simple little depiction + + align:start position:0% +simple uh simple little depiction + + + align:start position:0% +simple uh simple little depiction +here okay so once this + + align:start position:0% +here okay so once this + + + align:start position:0% +here okay so once this +uh this uh basic Paradigm had been had + + align:start position:0% +uh this uh basic Paradigm had been had + + + align:start position:0% +uh this uh basic Paradigm had been had +been straightened + + align:start position:0% +been straightened + + + align:start position:0% +been straightened +out + + align:start position:0% + + + + align:start position:0% + +gave rise then to this this idea then + + align:start position:0% +gave rise then to this this idea then + + + align:start position:0% +gave rise then to this this idea then +putting it all together that the + + align:start position:0% +putting it all together that the + + + align:start position:0% +putting it all together that the +information in DNA that a portion of it + + align:start position:0% +information in DNA that a portion of it + + + align:start position:0% +information in DNA that a portion of it +was would be copied into RNA and that + + align:start position:0% +was would be copied into RNA and that + + + align:start position:0% +was would be copied into RNA and that +would go out into the cytoplasm and then + + align:start position:0% +would go out into the cytoplasm and then + + + align:start position:0% +would go out into the cytoplasm and then +in the cytoplasm these translators the + + align:start position:0% +in the cytoplasm these translators the + + + align:start position:0% +in the cytoplasm these translators the +trnas would be able to decode the uh + + align:start position:0% +trnas would be able to decode the uh + + + align:start position:0% +trnas would be able to decode the uh +read the the nucleic acid information + + align:start position:0% +read the the nucleic acid information + + + align:start position:0% +read the the nucleic acid information +and use that to determine the linear + + align:start position:0% +and use that to determine the linear + + + align:start position:0% +and use that to determine the linear +order of amino acids + + align:start position:0% +order of amino acids + + + align:start position:0% +order of amino acids +uh in a protein uh Crick when he came up + + align:start position:0% +uh in a protein uh Crick when he came up + + + align:start position:0% +uh in a protein uh Crick when he came up +with this gave this the + + align:start position:0% + + + + align:start position:0% + +term the central + + align:start position:0% +term the central + + + align:start position:0% +term the central +dogma and it's a word that still people + + align:start position:0% +dogma and it's a word that still people + + + align:start position:0% +dogma and it's a word that still people +still use this term to apply to this + + align:start position:0% +still use this term to apply to this + + + align:start position:0% +still use this term to apply to this +this idea of information flow going from + + align:start position:0% +this idea of information flow going from + + + align:start position:0% +this idea of information flow going from +DNA to RNA and protein is still used to + + align:start position:0% +DNA to RNA and protein is still used to + + + align:start position:0% +DNA to RNA and protein is still used to +this day there's actually a a sort of + + align:start position:0% +this day there's actually a a sort of + + + align:start position:0% +this day there's actually a a sort of +little twist to that because at the time + + align:start position:0% +little twist to that because at the time + + + align:start position:0% +little twist to that because at the time +that Crick proposed the term he actually + + align:start position:0% +that Crick proposed the term he actually + + + align:start position:0% +that Crick proposed the term he actually +thought the word dogma meant uh an idea + + align:start position:0% +thought the word dogma meant uh an idea + + + align:start position:0% +thought the word dogma meant uh an idea +for which there is not reasonable + + align:start position:0% +for which there is not reasonable + + + align:start position:0% +for which there is not reasonable +evidence but he was sort of amused years + + align:start position:0% +evidence but he was sort of amused years + + + align:start position:0% +evidence but he was sort of amused years +later to realize that a more reasonable + + align:start position:0% +later to realize that a more reasonable + + + align:start position:0% +later to realize that a more reasonable +definition of Dogma is sort of something + + align:start position:0% +definition of Dogma is sort of something + + + align:start position:0% +definition of Dogma is sort of something +that a True Believer cannot doubt and so + + align:start position:0% +that a True Believer cannot doubt and so + + + align:start position:0% +that a True Believer cannot doubt and so +he kind of + + align:start position:0% +he kind of + + + align:start position:0% +he kind of +accidentally made an assertion that he + + align:start position:0% +accidentally made an assertion that he + + + align:start position:0% +accidentally made an assertion that he +was right but fortunately he was right + + align:start position:0% +was right but fortunately he was right + + + align:start position:0% +was right but fortunately he was right +um + + align:start position:0% + + + + align:start position:0% + +now + + align:start position:0% + + + + align:start position:0% + +the next big job though in working in + + align:start position:0% +the next big job though in working in + + + align:start position:0% +the next big job though in working in +working this out was to crack the + + align:start position:0% + + + + align:start position:0% + +code and it's fine to know that it's a + + align:start position:0% +code and it's fine to know that it's a + + + align:start position:0% +code and it's fine to know that it's a +three-letter code and it's fine to know + + align:start position:0% +three-letter code and it's fine to know + + + align:start position:0% +three-letter code and it's fine to know +it goes into RNA and and uh then the + + align:start position:0% +it goes into RNA and and uh then the + + + align:start position:0% +it goes into RNA and and uh then the +TRNA translated but if you can't can't + + align:start position:0% +TRNA translated but if you can't can't + + + align:start position:0% +TRNA translated but if you can't can't +if you can't crack the code then you + + align:start position:0% +if you can't crack the code then you + + + align:start position:0% +if you can't crack the code then you +have no idea what any of the + + align:start position:0% +have no idea what any of the + + + align:start position:0% +have no idea what any of the +information uh means it was sort of like + + align:start position:0% +information uh means it was sort of like + + + align:start position:0% +information uh means it was sort of like +before the Rosetta Stone when they could + + align:start position:0% +before the Rosetta Stone when they could + + + align:start position:0% +before the Rosetta Stone when they could +look at the higher hieroglyphics in the + + align:start position:0% +look at the higher hieroglyphics in the + + + align:start position:0% +look at the higher hieroglyphics in the +Egyptian tombs and they could see there + + align:start position:0% +Egyptian tombs and they could see there + + + align:start position:0% +Egyptian tombs and they could see there +was a lot of information and there were + + align:start position:0% +was a lot of information and there were + + + align:start position:0% +was a lot of information and there were +symbols and so on but they didn't know + + align:start position:0% +symbols and so on but they didn't know + + + align:start position:0% +symbols and so on but they didn't know +what it meant until finally they got + + align:start position:0% +what it meant until finally they got + + + align:start position:0% +what it meant until finally they got +something that allowed them to relate it + + align:start position:0% +something that allowed them to relate it + + + align:start position:0% +something that allowed them to relate it +to a language they didn't know and they + + align:start position:0% +to a language they didn't know and they + + + align:start position:0% +to a language they didn't know and they +were able to work out the principles so + + align:start position:0% +were able to work out the principles so + + + align:start position:0% +were able to work out the principles so +somehow uh scientists had then to crack + + align:start position:0% +somehow uh scientists had then to crack + + + align:start position:0% +somehow uh scientists had then to crack +the code and there were two + + align:start position:0% +the code and there were two + + + align:start position:0% +the code and there were two +um uh two scientists who played uh a + + align:start position:0% +um uh two scientists who played uh a + + + align:start position:0% +um uh two scientists who played uh a +really big role one was + + align:start position:0% +really big role one was + + + align:start position:0% +really big role one was +Marshall + + align:start position:0% + + + + align:start position:0% + +nurenberg who was at NIH and it's in + + align:start position:0% +nurenberg who was at NIH and it's in + + + align:start position:0% +nurenberg who was at NIH and it's in +fact still at NIH and the other one was + + align:start position:0% +fact still at NIH and the other one was + + + align:start position:0% +fact still at NIH and the other one was +an MI scientist who's on the same floor + + align:start position:0% +an MI scientist who's on the same floor + + + align:start position:0% +an MI scientist who's on the same floor +as me and MIT Goen uh corana and they + + align:start position:0% +as me and MIT Goen uh corana and they + + + align:start position:0% +as me and MIT Goen uh corana and they +used two different approaches but + + align:start position:0% +used two different approaches but + + + align:start position:0% +used two different approaches but +between these two approaches the the + + align:start position:0% +between these two approaches the the + + + align:start position:0% +between these two approaches the the +genetic code was was cracked and what um + + align:start position:0% +genetic code was was cracked and what um + + + align:start position:0% +genetic code was was cracked and what um +nerenberg did + + align:start position:0% +nerenberg did + + + align:start position:0% +nerenberg did +was to take a protein + + align:start position:0% + + + + align:start position:0% + +synthesizing extract that he knew needed + + align:start position:0% +synthesizing extract that he knew needed + + + align:start position:0% +synthesizing extract that he knew needed +RNA in order to work so that would + + align:start position:0% +RNA in order to work so that would + + + align:start position:0% +RNA in order to work so that would +wasn't a surprise at this point because + + align:start position:0% +wasn't a surprise at this point because + + + align:start position:0% +wasn't a surprise at this point because +people were thinking the RNA would be + + align:start position:0% +people were thinking the RNA would be + + + align:start position:0% +people were thinking the RNA would be +the message and what at that point the + + align:start position:0% +the message and what at that point the + + + align:start position:0% +the message and what at that point the +the ability to make uh synthesize uh + + align:start position:0% +the ability to make uh synthesize uh + + + align:start position:0% +the ability to make uh synthesize uh +nucleic acids was quite limited compared + + align:start position:0% +nucleic acids was quite limited compared + + + align:start position:0% +nucleic acids was quite limited compared +to what we do now and so there were + + align:start position:0% +to what we do now and so there were + + + align:start position:0% +to what we do now and so there were +different ways of making them uh + + align:start position:0% +different ways of making them uh + + + align:start position:0% +different ways of making them uh +sometimes you could do it enzymatically + + align:start position:0% +sometimes you could do it enzymatically + + + align:start position:0% +sometimes you could do it enzymatically +but what nernberg for example was able + + align:start position:0% +but what nernberg for example was able + + + align:start position:0% +but what nernberg for example was able +to make was polyu so this was an RNA + + align:start position:0% +to make was polyu so this was an RNA + + + align:start position:0% +to make was polyu so this was an RNA +that was just u u u u u u u u and then + + align:start position:0% +that was just u u u u u u u u and then + + + align:start position:0% +that was just u u u u u u u u and then +what he did was he set up 20 reactions + + align:start position:0% +what he did was he set up 20 reactions + + + align:start position:0% +what he did was he set up 20 reactions +and in every reaction he put some of + + align:start position:0% +and in every reaction he put some of + + + align:start position:0% +and in every reaction he put some of +this extract he put polyu and he put 19 + + align:start position:0% +this extract he put polyu and he put 19 + + + align:start position:0% +this extract he put polyu and he put 19 +of the of the amino acids that were um + + align:start position:0% +of the of the amino acids that were um + + + align:start position:0% +of the of the amino acids that were um +unlabeled and then only one amino acid + + align:start position:0% +unlabeled and then only one amino acid + + + align:start position:0% +unlabeled and then only one amino acid +that had radio label in it so he ran + + align:start position:0% +that had radio label in it so he ran + + + align:start position:0% +that had radio label in it so he ran +these 20 reactions and he waited to see + + align:start position:0% +these 20 reactions and he waited to see + + + align:start position:0% +these 20 reactions and he waited to see +could he get any in any of these did he + + align:start position:0% +could he get any in any of these did he + + + align:start position:0% +could he get any in any of these did he +get uh protein made that would have been + + align:start position:0% +get uh protein made that would have been + + + align:start position:0% +get uh protein made that would have been +Co by the polyu and what he ended up + + align:start position:0% +Co by the polyu and what he ended up + + + align:start position:0% +Co by the polyu and what he ended up +with was polyphenol + + align:start position:0% + + + + align:start position:0% + +alanine + + align:start position:0% + + + + align:start position:0% + +which you may recall when we were + + align:start position:0% +which you may recall when we were + + + align:start position:0% +which you may recall when we were +talking + + align:start position:0% +talking + + + align:start position:0% +talking +about + + align:start position:0% +about + + + align:start position:0% +about +structures of amino acids there's the + + align:start position:0% +structures of amino acids there's the + + + align:start position:0% +structures of amino acids there's the +basic backbone and + + align:start position:0% +basic backbone and + + + align:start position:0% +basic backbone and +the polyphenol is the one that has if + + align:start position:0% +the polyphenol is the one that has if + + + align:start position:0% +the polyphenol is the one that has if +you will a Benzene ring hanging off off + + align:start position:0% +you will a Benzene ring hanging off off + + + align:start position:0% +you will a Benzene ring hanging off off +the end and so what that meant was that + + align:start position:0% +the end and so what that meant was that + + + align:start position:0% +the end and so what that meant was that +uuu + + align:start position:0% +uuu + + + align:start position:0% +uuu +must + + align:start position:0% +must + + + align:start position:0% +must +code for fee + + align:start position:0% + + + + align:start position:0% + +or pheny alanine and if it's + + align:start position:0% +or pheny alanine and if it's + + + align:start position:0% +or pheny alanine and if it's +uu in the RNA that must + + align:start position:0% +uu in the RNA that must + + + align:start position:0% +uu in the RNA that must +mean that the DNA that encodes + + align:start position:0% +mean that the DNA that encodes + + + align:start position:0% +mean that the DNA that encodes +this must + + align:start position:0% +this must + + + align:start position:0% +this must +have must have that sequence a AA and + + align:start position:0% +have must have that sequence a AA and + + + align:start position:0% +have must have that sequence a AA and +TTT and you can see that one of the two + + align:start position:0% +TTT and you can see that one of the two + + + align:start position:0% +TTT and you can see that one of the two +two strands of the DNA since T base pair + + align:start position:0% +two strands of the DNA since T base pair + + + align:start position:0% +two strands of the DNA since T base pair +is the same as urine one of the strands + + align:start position:0% +is the same as urine one of the strands + + + align:start position:0% +is the same as urine one of the strands +in the the DNA is going to have the same + + align:start position:0% +in the the DNA is going to have the same + + + align:start position:0% +in the the DNA is going to have the same +sequence as one of the strands in the in + + align:start position:0% +sequence as one of the strands in the in + + + align:start position:0% +sequence as one of the strands in the in +the RNA now I'll just tell you one brief + + align:start position:0% +the RNA now I'll just tell you one brief + + + align:start position:0% +the RNA now I'll just tell you one brief +little anecdote I heard uh Marshall + + align:start position:0% +little anecdote I heard uh Marshall + + + align:start position:0% +little anecdote I heard uh Marshall +nberg talk at this this uh meeting they + + align:start position:0% +nberg talk at this this uh meeting they + + + align:start position:0% +nberg talk at this this uh meeting they +had to celebrate the 50th anniversary of + + align:start position:0% +had to celebrate the 50th anniversary of + + + align:start position:0% +had to celebrate the 50th anniversary of +discovery of DNA and um he posed + + align:start position:0% +discovery of DNA and um he posed + + + align:start position:0% +discovery of DNA and um he posed +something that I never thought about in + + align:start position:0% +something that I never thought about in + + + align:start position:0% +something that I never thought about in +my years of teaching this but might + + align:start position:0% +my years of teaching this but might + + + align:start position:0% +my years of teaching this but might +occur to you guys if we put it up a + + align:start position:0% +occur to you guys if we put it up a + + + align:start position:0% +occur to you guys if we put it up a +problem Set uh you all know something + + align:start position:0% +problem Set uh you all know something + + + align:start position:0% +problem Set uh you all know something +that Benzene is nothing but sort of + + align:start position:0% +that Benzene is nothing but sort of + + + align:start position:0% +that Benzene is nothing but sort of +these uh this is I call even referred to + + align:start position:0% +these uh this is I call even referred to + + + align:start position:0% +these uh this is I call even referred to +it as a as a Benzene ring it's a very + + align:start position:0% +it as a as a Benzene ring it's a very + + + align:start position:0% +it as a as a Benzene ring it's a very +organic kind of solvent so if we put on + + align:start position:0% +organic kind of solvent so if we put on + + + align:start position:0% +organic kind of solvent so if we put on +a problem set if you made polyphenol + + align:start position:0% +a problem set if you made polyphenol + + + align:start position:0% +a problem set if you made polyphenol +alanine would you expect this to be + + align:start position:0% +alanine would you expect this to be + + + align:start position:0% +alanine would you expect this to be +soluble in + + align:start position:0% +soluble in + + + align:start position:0% +soluble in +water this is very very hydrophobic very + + align:start position:0% +water this is very very hydrophobic very + + + align:start position:0% +water this is very very hydrophobic very +very water hating and your answer would + + align:start position:0% +very water hating and your answer would + + + align:start position:0% +very water hating and your answer would +be correct if you said no I wouldn't + + align:start position:0% +be correct if you said no I wouldn't + + + align:start position:0% +be correct if you said no I wouldn't +expect polyphenol alanine to be soluble + + align:start position:0% +expect polyphenol alanine to be soluble + + + align:start position:0% +expect polyphenol alanine to be soluble +in water in fact if we were in a protein + + align:start position:0% +in water in fact if we were in a protein + + + align:start position:0% +in water in fact if we were in a protein +we would expect it to probably be in the + + align:start position:0% +we would expect it to probably be in the + + + align:start position:0% +we would expect it to probably be in the +core where all the hydrophobic + + align:start position:0% +core where all the hydrophobic + + + align:start position:0% +core where all the hydrophobic +interactions the water hating Parts + + align:start position:0% +interactions the water hating Parts + + + align:start position:0% +interactions the water hating Parts +would go so Marshall nberg said when in + + align:start position:0% +would go so Marshall nberg said when in + + + align:start position:0% +would go so Marshall nberg said when in +his talk well he had he showed that he + + align:start position:0% +his talk well he had he showed that he + + + align:start position:0% +his talk well he had he showed that he +had Radioactive fanine in he still had + + align:start position:0% +had Radioactive fanine in he still had + + + align:start position:0% +had Radioactive fanine in he still had +to prove chemically that he had + + align:start position:0% +to prove chemically that he had + + + align:start position:0% +to prove chemically that he had +polyphenol alanine but he wasn't much of + + align:start position:0% +polyphenol alanine but he wasn't much of + + + align:start position:0% +polyphenol alanine but he wasn't much of +a biochemist so he walked down to the + + align:start position:0% +a biochemist so he walked down to the + + + align:start position:0% +a biochemist so he walked down to the +lab just below him at NI at NIH and + + align:start position:0% +lab just below him at NI at NIH and + + + align:start position:0% +lab just below him at NI at NIH and +walked in the door and saw the first + + align:start position:0% +walked in the door and saw the first + + + align:start position:0% +walked in the door and saw the first +person he said saw and said how do you + + align:start position:0% +person he said saw and said how do you + + + align:start position:0% +person he said saw and said how do you +um uh how do you solubilize polyphenol + + align:start position:0% +um uh how do you solubilize polyphenol + + + align:start position:0% +um uh how do you solubilize polyphenol +alanine let's make sure I got this right + + align:start position:0% +alanine let's make sure I got this right + + + align:start position:0% +alanine let's make sure I got this right +and the guy said oh you just take 33% + + align:start position:0% +and the guy said oh you just take 33% + + + align:start position:0% +and the guy said oh you just take 33% +hydrobromic acid and glacial acetic acid + + align:start position:0% +hydrobromic acid and glacial acetic acid + + + align:start position:0% +hydrobromic acid and glacial acetic acid +and and it works so he went back + + align:start position:0% +and and it works so he went back + + + align:start position:0% +and and it works so he went back +upstairs and dissolved it turned out it + + align:start position:0% +upstairs and dissolved it turned out it + + + align:start position:0% +upstairs and dissolved it turned out it +it dissolved in that he went on to + + align:start position:0% +it dissolved in that he went on to + + + align:start position:0% +it dissolved in that he went on to +characterize it and he said it didn't + + align:start position:0% +characterize it and he said it didn't + + + align:start position:0% +characterize it and he said it didn't +occur to him or he didn't learn till + + align:start position:0% +occur to him or he didn't learn till + + + align:start position:0% +occur to him or he didn't learn till +about 15 or 20 years later that he just + + align:start position:0% +about 15 or 20 years later that he just + + + align:start position:0% +about 15 or 20 years later that he just +walked up to the only person in the + + align:start position:0% +walked up to the only person in the + + + align:start position:0% +walked up to the only person in the +world who knew how to solubilize + + align:start position:0% +world who knew how to solubilize + + + align:start position:0% +world who knew how to solubilize +polyphenol + + align:start position:0% +polyphenol + + + align:start position:0% +polyphenol +by total coincidence this guy who we + + align:start position:0% +by total coincidence this guy who we + + + align:start position:0% +by total coincidence this guy who we +talked to had been working away trying + + align:start position:0% +talked to had been working away trying + + + align:start position:0% +talked to had been working away trying +to figure out a way and had come with + + align:start position:0% +to figure out a way and had come with + + + align:start position:0% +to figure out a way and had come with +this odd mix of hydrobromic acid and in + + align:start position:0% +this odd mix of hydrobromic acid and in + + + align:start position:0% +this odd mix of hydrobromic acid and in +glacial AIC and he just inste of you + + align:start position:0% +glacial AIC and he just inste of you + + + align:start position:0% +glacial AIC and he just inste of you +know all the places in the world he + + align:start position:0% +know all the places in the world he + + + align:start position:0% +know all the places in the world he +walked up to the one person who knew and + + align:start position:0% +walked up to the one person who knew and + + + align:start position:0% +walked up to the one person who knew and +and got the answer so the other part of + + align:start position:0% +and got the answer so the other part of + + + align:start position:0% +and got the answer so the other part of +the story then involves uh Goin K who I + + align:start position:0% +the story then involves uh Goin K who I + + + align:start position:0% +the story then involves uh Goin K who I +mentioned when I telling you initially + + align:start position:0% +mentioned when I telling you initially + + + align:start position:0% +mentioned when I telling you initially +about the the Nobel laurates at um at at + + align:start position:0% +about the the Nobel laurates at um at at + + + align:start position:0% +about the the Nobel laurates at um at at +uh MIT and Goin is a brilliant organic + + align:start position:0% +uh MIT and Goin is a brilliant organic + + + align:start position:0% +uh MIT and Goin is a brilliant organic +chemist he synthesized DNA uh you know + + align:start position:0% +chemist he synthesized DNA uh you know + + + align:start position:0% +chemist he synthesized DNA uh you know +there was a point where a whole issue of + + align:start position:0% +there was a point where a whole issue of + + + align:start position:0% +there was a point where a whole issue of +a journal came out that was nothing but + + align:start position:0% +a journal came out that was nothing but + + + align:start position:0% +a journal came out that was nothing but +his Labs work on synthesizing uh DNA + + align:start position:0% +his Labs work on synthesizing uh DNA + + + align:start position:0% +his Labs work on synthesizing uh DNA +well he was good at nucleic acids and + + align:start position:0% +well he was good at nucleic acids and + + + align:start position:0% +well he was good at nucleic acids and +one of the strategies that they could + + align:start position:0% +one of the strategies that they could + + + align:start position:0% +one of the strategies that they could +use chemically was they would make + + align:start position:0% +use chemically was they would make + + + align:start position:0% +use chemically was they would make +something like a d nucleotide like ca + + align:start position:0% +something like a d nucleotide like ca + + + align:start position:0% +something like a d nucleotide like ca +and then they were able to polymerize + + align:start position:0% +and then they were able to polymerize + + + align:start position:0% +and then they were able to polymerize +that to make a piece of RNA so they + + align:start position:0% +that to make a piece of RNA so they + + + align:start position:0% +that to make a piece of RNA so they +could make an + + align:start position:0% +could make an + + + align:start position:0% +could make an +RNA that had the sequence C c a c a c a + + align:start position:0% +RNA that had the sequence C c a c a c a + + + align:start position:0% +RNA that had the sequence C c a c a c a +c a and so on and what you can see from + + align:start position:0% +c a and so on and what you can see from + + + align:start position:0% +c a and so on and what you can see from +that is that there + + align:start position:0% +that is that there + + + align:start position:0% +that is that there +are two different codons in that one is + + align:start position:0% +are two different codons in that one is + + + align:start position:0% +are two different codons in that one is +uh CAC and the other is ACA and the + + align:start position:0% +uh CAC and the other is ACA and the + + + align:start position:0% +uh CAC and the other is ACA and the +reason he made it was he was + + align:start position:0% +reason he made it was he was + + + align:start position:0% +reason he made it was he was +synthesizing it by + + align:start position:0% +synthesizing it by + + + align:start position:0% +synthesizing it by +polymerizing um nucleotides so in these + + align:start position:0% +polymerizing um nucleotides so in these + + + align:start position:0% +polymerizing um nucleotides so in these +same kind of experiments there was + + align:start position:0% +same kind of experiments there was + + + align:start position:0% +same kind of experiments there was +describing before what they found this + + align:start position:0% +describing before what they found this + + + align:start position:0% +describing before what they found this +synthesized was alternating + + align:start position:0% + + + + align:start position:0% + +histadine and thine and it took you + + align:start position:0% +histadine and thine and it took you + + + align:start position:0% +histadine and thine and it took you +can't tell from that experiment alone + + align:start position:0% +can't tell from that experiment alone + + + align:start position:0% +can't tell from that experiment alone +one of those is must be U histadine and + + align:start position:0% +one of those is must be U histadine and + + + align:start position:0% +one of those is must be U histadine and +one of them must be thine but you can't + + align:start position:0% +one of them must be thine but you can't + + + align:start position:0% +one of them must be thine but you can't +tell from that experiment so more + + align:start position:0% +tell from that experiment so more + + + align:start position:0% +tell from that experiment so more +experiments were needed and what was + + align:start position:0% +experiments were needed and what was + + + align:start position:0% +experiments were needed and what was +learned from that experiment in that + + align:start position:0% +learned from that experiment in that + + + align:start position:0% +learned from that experiment in that +case was that CAC corresponded to + + align:start position:0% +case was that CAC corresponded to + + + align:start position:0% +case was that CAC corresponded to +histadine and ACA + + align:start position:0% +histadine and ACA + + + align:start position:0% +histadine and ACA +corresponded to to three andine so these + + align:start position:0% +corresponded to to three andine so these + + + align:start position:0% +corresponded to to three andine so these +kind of experiments were then uh put + + align:start position:0% +kind of experiments were then uh put + + + align:start position:0% +kind of experiments were then uh put +together to give what's known as the + + align:start position:0% +together to give what's known as the + + + align:start position:0% +together to give what's known as the +genetic code which is the three-letter + + align:start position:0% +genetic code which is the three-letter + + + align:start position:0% +genetic code which is the three-letter +words encoded in DNA that encode the + + align:start position:0% +words encoded in DNA that encode the + + + align:start position:0% +words encoded in DNA that encode the +sequence amino acids and proteins and + + align:start position:0% +sequence amino acids and proteins and + + + align:start position:0% +sequence amino acids and proteins and +there's it's usually displayed as a + + align:start position:0% +there's it's usually displayed as a + + + align:start position:0% +there's it's usually displayed as a +table and you read it in this way that + + align:start position:0% +table and you read it in this way that + + + align:start position:0% +table and you read it in this way that +this is the this thing over here is the + + align:start position:0% +this is the this thing over here is the + + + align:start position:0% +this is the this thing over here is the +first base in the codon across the top + + align:start position:0% +first base in the codon across the top + + + align:start position:0% +first base in the codon across the top +is the second base in the codon and down + + align:start position:0% +is the second base in the codon and down + + + align:start position:0% +is the second base in the codon and down +over here is the third base so if we go + + align:start position:0% +over here is the third base so if we go + + + align:start position:0% +over here is the third base so if we go +to + + align:start position:0% +to + + + align:start position:0% +to +um uh c as the first say the one for + + align:start position:0% +um uh c as the first say the one for + + + align:start position:0% +um uh c as the first say the one for +histadine we're just showing you C is + + align:start position:0% +histadine we're just showing you C is + + + align:start position:0% +histadine we're just showing you C is +the first letter a is the second letter + + align:start position:0% +the first letter a is the second letter + + + align:start position:0% +the first letter a is the second letter +so this is the box that's going to we're + + align:start position:0% +so this is the box that's going to we're + + + align:start position:0% +so this is the box that's going to we're +going to be looking at and if C is the + + align:start position:0% +going to be looking at and if C is the + + + align:start position:0% +going to be looking at and if C is the +third letter we can see it encodes + + align:start position:0% +third letter we can see it encodes + + + align:start position:0% +third letter we can see it encodes +histadine or a c come back to + + align:start position:0% +histadine or a c come back to + + + align:start position:0% +histadine or a c come back to +a uh then uh the a is certainly three + + align:start position:0% +a uh then uh the a is certainly three + + + align:start position:0% +a uh then uh the a is certainly three +but you can also see something else here + + align:start position:0% +but you can also see something else here + + + align:start position:0% +but you can also see something else here +and that is because there were 6 four + + align:start position:0% +and that is because there were 6 four + + + align:start position:0% +and that is because there were 6 four +possibilities uh with this three-letter + + align:start position:0% +possibilities uh with this three-letter + + + align:start position:0% +possibilities uh with this three-letter +word the code is what's known as + + align:start position:0% +word the code is what's known as + + + align:start position:0% +word the code is what's known as +degenerate that is there you there are + + align:start position:0% +degenerate that is there you there are + + + align:start position:0% +degenerate that is there you there are +more words in the in the uh genetic code + + align:start position:0% +more words in the in the uh genetic code + + + align:start position:0% +more words in the in the uh genetic code +than are needed to specify the + + align:start position:0% +than are needed to specify the + + + align:start position:0% +than are needed to specify the +um the number of amino acids that have + + align:start position:0% +um the number of amino acids that have + + + align:start position:0% +um the number of amino acids that have +to be coded so just want to make a + + align:start position:0% +to be coded so just want to make a + + + align:start position:0% +to be coded so just want to make a +couple of of points about this so the + + align:start position:0% +couple of of points about this so the + + + align:start position:0% +couple of of points about this so the +genetic + + align:start position:0% + + + + align:start position:0% + +code + + align:start position:0% + + + + align:start position:0% + +it's degenerate there are 61 codons that + + align:start position:0% +it's degenerate there are 61 codons that + + + align:start position:0% +it's degenerate there are 61 codons that +correspond + + align:start position:0% +correspond + + + align:start position:0% +correspond +to an amino acid and that means that + + align:start position:0% +to an amino acid and that means that + + + align:start position:0% +to an amino acid and that means that +some and think threein is a good example + + align:start position:0% +some and think threein is a good example + + + align:start position:0% +some and think threein is a good example +there's more than one word in the + + align:start position:0% +there's more than one word in the + + + align:start position:0% +there's more than one word in the +genetic code that means uh thine there + + align:start position:0% +genetic code that means uh thine there + + + align:start position:0% +genetic code that means uh thine there +were three codons for which there was no + + align:start position:0% +were three codons for which there was no + + + align:start position:0% +were three codons for which there was no +corresponding amino + + align:start position:0% + + + + align:start position:0% + +acid + + align:start position:0% +acid + + + align:start position:0% +acid +and those mean stop and that would make + + align:start position:0% +and those mean stop and that would make + + + align:start position:0% +and those mean stop and that would make +sense because if you're reading down a + + align:start position:0% +sense because if you're reading down a + + + align:start position:0% +sense because if you're reading down a +nucleic acid piece of RNA at some point + + align:start position:0% +nucleic acid piece of RNA at some point + + + align:start position:0% +nucleic acid piece of RNA at some point +you'd have to end the protein and so + + align:start position:0% +you'd have to end the protein and so + + + align:start position:0% +you'd have to end the protein and so +there are actually three that are that + + align:start position:0% +there are actually three that are that + + + align:start position:0% +there are actually three that are that +are used for that + + align:start position:0% +are used for that + + + align:start position:0% +are used for that +purpose and know there's some small + + align:start position:0% +purpose and know there's some small + + + align:start position:0% +purpose and know there's some small +variation on this uh in in + + align:start position:0% +variation on this uh in in + + + align:start position:0% +variation on this uh in in +nature there's usually one + + align:start position:0% + + + + align:start position:0% + +oops one amino acid that's used for + + align:start position:0% +oops one amino acid that's used for + + + align:start position:0% +oops one amino acid that's used for +starting a protein and that's methine + + align:start position:0% +starting a protein and that's methine + + + align:start position:0% +starting a protein and that's methine +and it's + + align:start position:0% +and it's + + + align:start position:0% +and it's +a right there now some of this stuff + + align:start position:0% +a right there now some of this stuff + + + align:start position:0% +a right there now some of this stuff +probably sounds like it's been around + + align:start position:0% +probably sounds like it's been around + + + align:start position:0% +probably sounds like it's been around +forever and that's certainly true of + + align:start position:0% +forever and that's certainly true of + + + align:start position:0% +forever and that's certainly true of +some of the stuff you hear in in um in + + align:start position:0% +some of the stuff you hear in in um in + + + align:start position:0% +some of the stuff you hear in in um in +your chemistry and math physics courses + + align:start position:0% +your chemistry and math physics courses + + + align:start position:0% +your chemistry and math physics courses +just want to drive you home when I was + + align:start position:0% +just want to drive you home when I was + + + align:start position:0% +just want to drive you home when I was +in undergrad Watson's first book called + + align:start position:0% +in undergrad Watson's first book called + + + align:start position:0% +in undergrad Watson's first book called +the molecular biology of the Gene and + + align:start position:0% +the molecular biology of the Gene and + + + align:start position:0% +the molecular biology of the Gene and +come out so I was when I was your age + + align:start position:0% +come out so I was when I was your age + + + align:start position:0% +come out so I was when I was your age +and I realized I look ancient but you + + align:start position:0% +and I realized I look ancient but you + + + align:start position:0% +and I realized I look ancient but you +know I'm still at least I'm still here + + align:start position:0% +know I'm still at least I'm still here + + + align:start position:0% +know I'm still at least I'm still here +um uh when I uh when I was an undergrad + + align:start position:0% +um uh when I uh when I was an undergrad + + + align:start position:0% +um uh when I uh when I was an undergrad +I had Watson's book this was the genetic + + align:start position:0% +I had Watson's book this was the genetic + + + align:start position:0% +I had Watson's book this was the genetic +code that was in the book the genetic + + align:start position:0% +code that was in the book the genetic + + + align:start position:0% +code that was in the book the genetic +code as of May 1965 and you'll notice + + align:start position:0% +code as of May 1965 and you'll notice + + + align:start position:0% +code as of May 1965 and you'll notice +there are a bunch of there gaps in here + + align:start position:0% +there are a bunch of there gaps in here + + + align:start position:0% +there are a bunch of there gaps in here +and all the things that are underlined + + align:start position:0% +and all the things that are underlined + + + align:start position:0% +and all the things that are underlined +were things that for which there was a + + align:start position:0% +were things that for which there was a + + + align:start position:0% +were things that for which there was a +tentative assignment so although you may + + align:start position:0% +tentative assignment so although you may + + + align:start position:0% +tentative assignment so although you may +take this think that it's been knowledge + + align:start position:0% +take this think that it's been knowledge + + + align:start position:0% +take this think that it's been knowledge +that's been around forever it was still + + align:start position:0% +that's been around forever it was still + + + align:start position:0% +that's been around forever it was still +you know was in wasn't even complete in + + align:start position:0% +you know was in wasn't even complete in + + + align:start position:0% +you know was in wasn't even complete in +the textbook when I was when I was an + + align:start position:0% +the textbook when I was when I was an + + + align:start position:0% +the textbook when I was when I was an +undergrad + + align:start position:0% +undergrad + + + align:start position:0% +undergrad +okay okay so one of the things then + + align:start position:0% +okay okay so one of the things then + + + align:start position:0% +okay okay so one of the things then +that's important to think about uh the + + align:start position:0% +that's important to think about uh the + + + align:start position:0% +that's important to think about uh the +nucleic acid stuff there's there's this + + align:start position:0% +nucleic acid stuff there's there's this + + + align:start position:0% +nucleic acid stuff there's there's this +is the basis of how U proteins are coded + + align:start position:0% +is the basis of how U proteins are coded + + + align:start position:0% +is the basis of how U proteins are coded +in the DNA but everything else has to be + + align:start position:0% +in the DNA but everything else has to be + + + align:start position:0% +in the DNA but everything else has to be +there too and the genetic + + align:start position:0% +there too and the genetic + + + align:start position:0% +there too and the genetic +code that's what we've been talking + + align:start position:0% + + + + align:start position:0% + +about is + + align:start position:0% + + + + align:start position:0% + +universal but there are + + align:start position:0% + + + + align:start position:0% + +other + + align:start position:0% + + + + align:start position:0% + +languages written in the + + align:start position:0% + + + + align:start position:0% + +DNA that are not + + align:start position:0% +DNA that are not + + + align:start position:0% +DNA that are not +Universal and one of them was that + + align:start position:0% +Universal and one of them was that + + + align:start position:0% +Universal and one of them was that +little example I gave you with an origin + + align:start position:0% +little example I gave you with an origin + + + align:start position:0% +little example I gave you with an origin +of + + align:start position:0% +of + + + align:start position:0% +of +replication eoli only starts DNA + + align:start position:0% +replication eoli only starts DNA + + + align:start position:0% +replication eoli only starts DNA +replication at one very particular point + + align:start position:0% +replication at one very particular point + + + align:start position:0% +replication at one very particular point +in its chromosome so it is a particular + + align:start position:0% +in its chromosome so it is a particular + + + align:start position:0% +in its chromosome so it is a particular +sequence of DNA it's actually about 250 + + align:start position:0% +sequence of DNA it's actually about 250 + + + align:start position:0% +sequence of DNA it's actually about 250 +nucleotides long so you could think of + + align:start position:0% +nucleotides long so you could think of + + + align:start position:0% +nucleotides long so you could think of +that as a language it's a like starting + + align:start position:0% +that as a language it's a like starting + + + align:start position:0% +that as a language it's a like starting +DNA a chromosome replication language + + align:start position:0% +DNA a chromosome replication language + + + align:start position:0% +DNA a chromosome replication language +it's only got one word in it and the + + align:start position:0% +it's only got one word in it and the + + + align:start position:0% +it's only got one word in it and the +word is 250 nucleotides BL another place + + align:start position:0% +word is 250 nucleotides BL another place + + + align:start position:0% +word is 250 nucleotides BL another place +that's very important and that is if + + align:start position:0% +that's very important and that is if + + + align:start position:0% +that's very important and that is if +you're going to make an RNA copy if + + align:start position:0% +you're going to make an RNA copy if + + + align:start position:0% +you're going to make an RNA copy if +you're going to do + + align:start position:0% +you're going to do + + + align:start position:0% +you're going to do +transcription of a piece of + + align:start position:0% +transcription of a piece of + + + align:start position:0% +transcription of a piece of +DNA + + align:start position:0% +DNA + + + align:start position:0% +DNA +and this is the I'll call this the + + align:start position:0% +and this is the I'll call this the + + + align:start position:0% +and this is the I'll call this the +coding + + align:start position:0% +coding + + + align:start position:0% +coding +sequence this would be the sequence of + + align:start position:0% +sequence this would be the sequence of + + + align:start position:0% +sequence this would be the sequence of +three-letter words that would specify + + align:start position:0% +three-letter words that would specify + + + align:start position:0% +three-letter words that would specify +the amino acid of the of the protein if + + align:start position:0% +the amino acid of the of the protein if + + + align:start position:0% +the amino acid of the of the protein if +you were going to make an RNA copy of + + align:start position:0% +you were going to make an RNA copy of + + + align:start position:0% +you were going to make an RNA copy of +that you would have to somewhere have + + align:start position:0% +that you would have to somewhere have + + + align:start position:0% +that you would have to somewhere have +something here that's a sequence up here + + align:start position:0% +something here that's a sequence up here + + + align:start position:0% +something here that's a sequence up here +that means start + + align:start position:0% +that means start + + + align:start position:0% +that means start +transcription + + align:start position:0% + + + + align:start position:0% + +and one at the end some other sequence + + align:start position:0% +and one at the end some other sequence + + + align:start position:0% +and one at the end some other sequence +of of uh letters in the nucleic acid + + align:start position:0% +of of uh letters in the nucleic acid + + + align:start position:0% +of of uh letters in the nucleic acid +that would mean stop + + align:start position:0% + + + + align:start position:0% + +transcription this is + + align:start position:0% +transcription this is + + + align:start position:0% +transcription this is +given the technical term it's referred + + align:start position:0% +given the technical term it's referred + + + align:start position:0% +given the technical term it's referred +to as a + + align:start position:0% +to as a + + + align:start position:0% +to as a +promoter the stop + + align:start position:0% +promoter the stop + + + align:start position:0% +promoter the stop +one is referred to as a as a + + align:start position:0% +one is referred to as a as a + + + align:start position:0% +one is referred to as a as a +terminator and these uh will say more + + align:start position:0% +terminator and these uh will say more + + + align:start position:0% +terminator and these uh will say more +about this cuz one of the thing the + + align:start position:0% +about this cuz one of the thing the + + + align:start position:0% +about this cuz one of the thing the +beauties of having this system of + + align:start position:0% +beauties of having this system of + + + align:start position:0% +beauties of having this system of +getting uh making an RNA copy is it + + align:start position:0% +getting uh making an RNA copy is it + + + align:start position:0% +getting uh making an RNA copy is it +provides a beautiful point of Regulation + + align:start position:0% +provides a beautiful point of Regulation + + + align:start position:0% +provides a beautiful point of Regulation +because the cell can determine whether + + align:start position:0% +because the cell can determine whether + + + align:start position:0% +because the cell can determine whether +or not it's going to make a particular + + align:start position:0% +or not it's going to make a particular + + + align:start position:0% +or not it's going to make a particular +protein by whether or not it chooses to + + align:start position:0% +protein by whether or not it chooses to + + + align:start position:0% +protein by whether or not it chooses to +make the um make make the protein or not + + align:start position:0% +make the um make make the protein or not + + + align:start position:0% +make the um make make the protein or not +and so U having this RNA intermediate + + align:start position:0% +and so U having this RNA intermediate + + + align:start position:0% +and so U having this RNA intermediate +and being able to control transcription + + align:start position:0% +and being able to control transcription + + + align:start position:0% +and being able to control transcription +is a really important part of the whole + + align:start position:0% +is a really important part of the whole + + + align:start position:0% +is a really important part of the whole +regulation that makes + + align:start position:0% +regulation that makes + + + align:start position:0% +regulation that makes +uh that makes life U possible the + + align:start position:0% +uh that makes life U possible the + + + align:start position:0% +uh that makes life U possible the +transcription is carried out by an + + align:start position:0% +transcription is carried out by an + + + align:start position:0% +transcription is carried out by an +enzyme that's known as + + align:start position:0% + + + + align:start position:0% + +RNA polymerase and let me make one more + + align:start position:0% +RNA polymerase and let me make one more + + + align:start position:0% +RNA polymerase and let me make one more +point just I was + + align:start position:0% +point just I was + + + align:start position:0% +point just I was +this these promoters and + + align:start position:0% + + + + align:start position:0% + +Terminators are not + + align:start position:0% +Terminators are not + + + align:start position:0% +Terminators are not +Universal so when we talk about + + align:start position:0% +Universal so when we talk about + + + align:start position:0% +Universal so when we talk about +recombinant D a little bit in the course + + align:start position:0% +recombinant D a little bit in the course + + + align:start position:0% +recombinant D a little bit in the course +if I take a mouse Gene and I put it in + + align:start position:0% +if I take a mouse Gene and I put it in + + + align:start position:0% +if I take a mouse Gene and I put it in +eoli even though the genetic code is the + + align:start position:0% +eoli even though the genetic code is the + + + align:start position:0% +eoli even though the genetic code is the +same we might have all the same sequence + + align:start position:0% +same we might have all the same sequence + + + align:start position:0% +same we might have all the same sequence +of amino acids specified you won't get + + align:start position:0% +of amino acids specified you won't get + + + align:start position:0% +of amino acids specified you won't get +the RNA made because the thing the + + align:start position:0% +the RNA made because the thing the + + + align:start position:0% +the RNA made because the thing the +sequences that say start transcription + + align:start position:0% +sequences that say start transcription + + + align:start position:0% +sequences that say start transcription +and stop transcription are different + + align:start position:0% +and stop transcription are different + + + align:start position:0% +and stop transcription are different +between a mouse and a bacterium even + + align:start position:0% +between a mouse and a bacterium even + + + align:start position:0% +between a mouse and a bacterium even +though the genetic code is the same so + + align:start position:0% +though the genetic code is the same so + + + align:start position:0% +though the genetic code is the same so +you can kind of see from first + + align:start position:0% +you can kind of see from first + + + align:start position:0% +you can kind of see from first +principles if you're doing recombinant + + align:start position:0% +principles if you're doing recombinant + + + align:start position:0% +principles if you're doing recombinant +DNA and you wanted to express the most + + align:start position:0% +DNA and you wanted to express the most + + + align:start position:0% +DNA and you wanted to express the most +protein in coli you would have to fiddle + + align:start position:0% +protein in coli you would have to fiddle + + + align:start position:0% +protein in coli you would have to fiddle +around with the sequences up here and + + align:start position:0% +around with the sequences up here and + + + align:start position:0% +around with the sequences up here and +the sequences down there the parts that + + align:start position:0% +the sequences down there the parts that + + + align:start position:0% +the sequences down there the parts that +are are not + + align:start position:0% +are are not + + + align:start position:0% +are are not +Universal guys with me okay so what what + + align:start position:0% +Universal guys with me okay so what what + + + align:start position:0% +Universal guys with me okay so what what +what does an RNA uh polymerase do it + + align:start position:0% +what does an RNA uh polymerase do it + + + align:start position:0% +what does an RNA uh polymerase do it +sort it recognizes this this sequence + + align:start position:0% +sort it recognizes this this sequence + + + align:start position:0% +sort it recognizes this this sequence +and then it teases the strands apart to + + align:start position:0% +and then it teases the strands apart to + + + align:start position:0% +and then it teases the strands apart to +make a little bubble like + + align:start position:0% +make a little bubble like + + + align:start position:0% +make a little bubble like +this so let's say a t a g c ta a so the + + align:start position:0% +this so let's say a t a g c ta a so the + + + align:start position:0% +this so let's say a t a g c ta a so the +other strand then would be t a t + + align:start position:0% +other strand then would be t a t + + + align:start position:0% +other strand then would be t a t +CG ta and then RNA plas + + align:start position:0% +CG ta and then RNA plas + + + align:start position:0% +CG ta and then RNA plas +unlike um a DNA plase can begin a chain + + align:start position:0% +unlike um a DNA plase can begin a chain + + + align:start position:0% +unlike um a DNA plase can begin a chain +denovo remember an important thing about + + align:start position:0% +denovo remember an important thing about + + + align:start position:0% +denovo remember an important thing about +DNA plases was they had to have a primer + + align:start position:0% +DNA plases was they had to have a primer + + + align:start position:0% +DNA plases was they had to have a primer +Terminus to get started that was why + + align:start position:0% +Terminus to get started that was why + + + align:start position:0% +Terminus to get started that was why +they had to use those okazaki fragments + + align:start position:0% +they had to use those okazaki fragments + + + align:start position:0% +they had to use those okazaki fragments +so this is DNA this would be five Prime + + align:start position:0% +so this is DNA this would be five Prime + + + align:start position:0% +so this is DNA this would be five Prime +three prime three prime and five Prime + + align:start position:0% +three prime three prime and five Prime + + + align:start position:0% +three prime three prime and five Prime +and it will what an RNA ply can do it + + align:start position:0% +and it will what an RNA ply can do it + + + align:start position:0% +and it will what an RNA ply can do it +uses D ATP D + + align:start position:0% +uses D ATP D + + + align:start position:0% +uses D ATP D +GTP + + align:start position:0% +GTP + + + align:start position:0% +GTP +dctp and the UTP it uses triphosphates + + align:start position:0% +dctp and the UTP it uses triphosphates + + + align:start position:0% +dctp and the UTP it uses triphosphates +excuse me not not get rid of the excuse + + align:start position:0% +excuse me not not get rid of the excuse + + + align:start position:0% +excuse me not not get rid of the excuse +me my mistake no no Deoxys here of + + align:start position:0% +me my mistake no no Deoxys here of + + + align:start position:0% +me my mistake no no Deoxys here of +course this is RNA uses ATP GTP CTP and + + align:start position:0% +course this is RNA uses ATP GTP CTP and + + + align:start position:0% +course this is RNA uses ATP GTP CTP and +uh and UTP as the substrates so it uses + + align:start position:0% +uh and UTP as the substrates so it uses + + + align:start position:0% +uh and UTP as the substrates so it uses +triphosphates just the same way DNA + + align:start position:0% +triphosphates just the same way DNA + + + align:start position:0% +triphosphates just the same way DNA +polymerases do and then it's able to + + align:start position:0% +polymerases do and then it's able to + + + align:start position:0% +polymerases do and then it's able to +start a chain d o and it + + align:start position:0% +start a chain d o and it + + + align:start position:0% +start a chain d o and it +synthesizes the + + align:start position:0% +synthesizes the + + + align:start position:0% +synthesizes the +RNA in a five Prime to three prime + + align:start position:0% +RNA in a five Prime to three prime + + + align:start position:0% +RNA in a five Prime to three prime +Direction the same direction that a + + align:start position:0% +Direction the same direction that a + + + align:start position:0% +Direction the same direction that a +strand of DNA is made by DNA polymerase + + align:start position:0% +strand of DNA is made by DNA polymerase + + + align:start position:0% +strand of DNA is made by DNA polymerase +so it would copy here and so it would + + align:start position:0% +so it would copy here and so it would + + + align:start position:0% +so it would copy here and so it would +put in an a opposite a t and then + + align:start position:0% +put in an a opposite a t and then + + + align:start position:0% +put in an a opposite a t and then +because it's R A it will put in a u + + align:start position:0% +because it's R A it will put in a u + + + align:start position:0% +because it's R A it will put in a u +opposite an A and then an a g c a and u + + align:start position:0% +opposite an A and then an a g c a and u + + + align:start position:0% +opposite an A and then an a g c a and u +and so on so + + align:start position:0% +and so on so + + + align:start position:0% +and so on so +this right here is the + + align:start position:0% +this right here is the + + + align:start position:0% +this right here is the +beginning of the RNA that's being + + align:start position:0% +beginning of the RNA that's being + + + align:start position:0% +beginning of the RNA that's being +synthesized by the uh RNA + + align:start position:0% +synthesized by the uh RNA + + + align:start position:0% +synthesized by the uh RNA +polymerase this + + align:start position:0% + + + + align:start position:0% + +strand it's known as the transcribed + + align:start position:0% +strand it's known as the transcribed + + + align:start position:0% +strand it's known as the transcribed +Strand and by default then that one is + + align:start position:0% +Strand and by default then that one is + + + align:start position:0% +Strand and by default then that one is +the non-transcribed Strand what you can + + align:start position:0% +the non-transcribed Strand what you can + + + align:start position:0% +the non-transcribed Strand what you can +see by doing this it's making in RNA the + + align:start position:0% +see by doing this it's making in RNA the + + + align:start position:0% +see by doing this it's making in RNA the +same sequences up here except that + + align:start position:0% +same sequences up here except that + + + align:start position:0% +same sequences up here except that +everywhere there's a there's no u in the + + align:start position:0% +everywhere there's a there's no u in the + + + align:start position:0% +everywhere there's a there's no u in the +in the uh + + align:start position:0% +in the uh + + + align:start position:0% +in the uh +DNA so the final thing then is how the + + align:start position:0% +DNA so the final thing then is how the + + + align:start position:0% +DNA so the final thing then is how the +how this information gets all put + + align:start position:0% +how this information gets all put + + + align:start position:0% +how this information gets all put +together to make + + align:start position:0% +together to make + + + align:start position:0% +together to make +proteins and protein synthesis is done + + align:start position:0% +proteins and protein synthesis is done + + + align:start position:0% +proteins and protein synthesis is done +by an amazing machine known as a + + align:start position:0% +by an amazing machine known as a + + + align:start position:0% +by an amazing machine known as a +ribosome it's made up of some + + align:start position:0% +ribosome it's made up of some + + + align:start position:0% +ribosome it's made up of some +special large + + align:start position:0% +special large + + + align:start position:0% +special large +rnas + + align:start position:0% + + + + align:start position:0% + +called R + + align:start position:0% +called R + + + align:start position:0% +called R +rnas some proteins as well these are + + align:start position:0% +rnas some proteins as well these are + + + align:start position:0% +rnas some proteins as well these are +make up the ribosome and then it needs a + + align:start position:0% +make up the ribosome and then it needs a + + + align:start position:0% +make up the ribosome and then it needs a +messenger + + align:start position:0% +messenger + + + align:start position:0% +messenger +RNA uh and it needs the + + align:start position:0% +RNA uh and it needs the + + + align:start position:0% +RNA uh and it needs the +various trnas Each of which carries uh + + align:start position:0% +various trnas Each of which carries uh + + + align:start position:0% +various trnas Each of which carries uh +an amino acid that's appropriate to its + + align:start position:0% +an amino acid that's appropriate to its + + + align:start position:0% +an amino acid that's appropriate to its +its + + align:start position:0% +its + + + align:start position:0% +its +anticodon and the in very briefly sort + + align:start position:0% +anticodon and the in very briefly sort + + + align:start position:0% +anticodon and the in very briefly sort +of the way this is and you can see this + + align:start position:0% +of the way this is and you can see this + + + align:start position:0% +of the way this is and you can see this +in in your + + align:start position:0% +in in your + + + align:start position:0% +in in your +textbook what the ribosome does is it + + align:start position:0% +textbook what the ribosome does is it + + + align:start position:0% +textbook what the ribosome does is it +takes it's sort of a let's consider this + + align:start position:0% +takes it's sort of a let's consider this + + + align:start position:0% +takes it's sort of a let's consider this +is the messenger RNA a I'm just going to + + align:start position:0% +is the messenger RNA a I'm just going to + + + align:start position:0% +is the messenger RNA a I'm just going to +take three codons + + align:start position:0% +take three codons + + + align:start position:0% +take three codons +here and this messenger and I threads + + align:start position:0% +here and this messenger and I threads + + + align:start position:0% +here and this messenger and I threads +into the the ribosome and I'll sort of + + align:start position:0% +into the the ribosome and I'll sort of + + + align:start position:0% +into the the ribosome and I'll sort of +show a kind of a it's able to recognize + + align:start position:0% +show a kind of a it's able to recognize + + + align:start position:0% +show a kind of a it's able to recognize +the first codon and the second codeon + + align:start position:0% +the first codon and the second codeon + + + align:start position:0% +the first codon and the second codeon +remember of course there's no spacing + + align:start position:0% +remember of course there's no spacing + + + align:start position:0% +remember of course there's no spacing +like this in the RNA and then in the + + align:start position:0% +like this in the RNA and then in the + + + align:start position:0% +like this in the RNA and then in the +context of this large uh Factory it's + + align:start position:0% +context of this large uh Factory it's + + + align:start position:0% +context of this large uh Factory it's +able to find the TRNA that has amino + + align:start position:0% +able to find the TRNA that has amino + + + align:start position:0% +able to find the TRNA that has amino +acid one and the the anticodon that + + align:start position:0% +acid one and the the anticodon that + + + align:start position:0% +acid one and the the anticodon that +would correspond to this the TR that has + + align:start position:0% +would correspond to this the TR that has + + + align:start position:0% +would correspond to this the TR that has +the next amino acid attached and its + + align:start position:0% +the next amino acid attached and its + + + align:start position:0% +the next amino acid attached and its +anticodon so you can see what's happened + + align:start position:0% +anticodon so you can see what's happened + + + align:start position:0% +anticodon so you can see what's happened +that it's been able to order the first + + align:start position:0% +that it's been able to order the first + + + align:start position:0% +that it's been able to order the first +amino acid coded by that codon and put + + align:start position:0% +amino acid coded by that codon and put + + + align:start position:0% +amino acid coded by that codon and put +it physically right next to the the um + + align:start position:0% +it physically right next to the the um + + + align:start position:0% +it physically right next to the the um +the next amino acid that's coded here + + align:start position:0% +the next amino acid that's coded here + + + align:start position:0% +the next amino acid that's coded here +and then it + + align:start position:0% + + + + align:start position:0% + +catalyzes the formation of a peptide + + align:start position:0% + + + + align:start position:0% + +bond what happens when that does is the + + align:start position:0% +bond what happens when that does is the + + + align:start position:0% +bond what happens when that does is the +way this amino acid is joined to the + + align:start position:0% +way this amino acid is joined to the + + + align:start position:0% +way this amino acid is joined to the +TRNA there's energy energ stored in that + + align:start position:0% +TRNA there's energy energ stored in that + + + align:start position:0% +TRNA there's energy energ stored in that +Bond and so thermodynamically that was + + align:start position:0% +Bond and so thermodynamically that was + + + align:start position:0% +Bond and so thermodynamically that was +that allows this Bond formation to go + + align:start position:0% +that allows this Bond formation to go + + + align:start position:0% +that allows this Bond formation to go +and now you end up essentially with this + + align:start position:0% +and now you end up essentially with this + + + align:start position:0% +and now you end up essentially with this +and what happens now is everything + + align:start position:0% +and what happens now is everything + + + align:start position:0% +and what happens now is everything +clicks over + + align:start position:0% + + + + align:start position:0% + +one so you could think of it as this + + align:start position:0% +one so you could think of it as this + + + align:start position:0% +one so you could think of it as this +this whole RNA shifts over one so the + + align:start position:0% +this whole RNA shifts over one so the + + + align:start position:0% +this whole RNA shifts over one so the +the one that used to be here is now + + align:start position:0% +the one that used to be here is now + + + align:start position:0% +the one that used to be here is now +sticking + + align:start position:0% + + + + align:start position:0% + +outside here's part of the + + align:start position:0% +outside here's part of the + + + align:start position:0% +outside here's part of the +ribosome here's the next codon + + align:start position:0% +ribosome here's the next codon + + + align:start position:0% +ribosome here's the next codon +this what we have here is the TRNA it's + + align:start position:0% +this what we have here is the TRNA it's + + + align:start position:0% +this what we have here is the TRNA it's +got amino acid 2 joined to amino acid + + align:start position:0% +got amino acid 2 joined to amino acid + + + align:start position:0% +got amino acid 2 joined to amino acid +one the next codon specifies the next + + align:start position:0% +one the next codon specifies the next + + + align:start position:0% +one the next codon specifies the next +amino acid which is three and the and + + align:start position:0% +amino acid which is three and the and + + + align:start position:0% +amino acid which is three and the and +the process is then able to to go on + + align:start position:0% +the process is then able to to go on + + + align:start position:0% +the process is then able to to go on +like that now the r the structure of the + + align:start position:0% +like that now the r the structure of the + + + align:start position:0% +like that now the r the structure of the +ribosome the crystal structure of the + + align:start position:0% +ribosome the crystal structure of the + + + align:start position:0% +ribosome the crystal structure of the +ribosome was just finished and I guess + + align:start position:0% +ribosome was just finished and I guess + + + align:start position:0% +ribosome was just finished and I guess +we've got as many lights out as we can + + align:start position:0% +we've got as many lights out as we can + + + align:start position:0% +we've got as many lights out as we can +do right now um it's absolutely + + align:start position:0% +do right now um it's absolutely + + + align:start position:0% +do right now um it's absolutely +remarkable it's mostly + + align:start position:0% +remarkable it's mostly + + + align:start position:0% +remarkable it's mostly +RNA uh this is the gray stuff and the + + align:start position:0% +RNA uh this is the gray stuff and the + + + align:start position:0% +RNA uh this is the gray stuff and the +blue stuff are two huge rnas that are + + align:start position:0% +blue stuff are two huge rnas that are + + + align:start position:0% +blue stuff are two huge rnas that are +all folded up in three-dimensional space + + align:start position:0% +all folded up in three-dimensional space + + + align:start position:0% +all folded up in three-dimensional space +and these things that are sort of stuck + + align:start position:0% +and these things that are sort of stuck + + + align:start position:0% +and these things that are sort of stuck +on the outside these purple things here + + align:start position:0% +on the outside these purple things here + + + align:start position:0% +on the outside these purple things here +or the the dark blue things here that + + align:start position:0% +or the the dark blue things here that + + + align:start position:0% +or the the dark blue things here that +sort of look like cherries stuck on the + + align:start position:0% +sort of look like cherries stuck on the + + + align:start position:0% +sort of look like cherries stuck on the +outside of a cake those are proteins so + + align:start position:0% +outside of a cake those are proteins so + + + align:start position:0% +outside of a cake those are proteins so +most of this is RNA Big Balls of RNA + + align:start position:0% +most of this is RNA Big Balls of RNA + + + align:start position:0% +most of this is RNA Big Balls of RNA +with proteins kind of decor ating the + + align:start position:0% +with proteins kind of decor ating the + + + align:start position:0% +with proteins kind of decor ating the +outside the messenger RNA is a green + + align:start position:0% +outside the messenger RNA is a green + + + align:start position:0% +outside the messenger RNA is a green +thing that snakes through there's the + + align:start position:0% +thing that snakes through there's the + + + align:start position:0% +thing that snakes through there's the +messenger RNA see it's snaking through + + align:start position:0% +messenger RNA see it's snaking through + + + align:start position:0% +messenger RNA see it's snaking through +and maybe you can recognize in the + + align:start position:0% +and maybe you can recognize in the + + + align:start position:0% +and maybe you can recognize in the +middle this this TRNA uh there's an + + align:start position:0% +middle this this TRNA uh there's an + + + align:start position:0% +middle this this TRNA uh there's an +orange one and a yellow one those + + align:start position:0% +orange one and a yellow one those + + + align:start position:0% +orange one and a yellow one those +correspond to the t two TRNA I depicted + + align:start position:0% +correspond to the t two TRNA I depicted + + + align:start position:0% +correspond to the t two TRNA I depicted +here and I'm just going to see if I can + + align:start position:0% +here and I'm just going to see if I can + + + align:start position:0% +here and I'm just going to see if I can +stop this at a there's a there's a + + align:start position:0% +stop this at a there's a there's a + + + align:start position:0% +stop this at a there's a there's a +Viewpoint I'd like you to see uh when it + + align:start position:0% +Viewpoint I'd like you to see uh when it + + + align:start position:0% +Viewpoint I'd like you to see uh when it +comes around again here in just a sec + + align:start position:0% +comes around again here in just a sec + + + align:start position:0% +comes around again here in just a sec +I'll see if I can catch it there right + + align:start position:0% +I'll see if I can catch it there right + + + align:start position:0% +I'll see if I can catch it there right +there + + align:start position:0% +there + + + align:start position:0% +there +this is the here's one of the trnas in + + align:start position:0% +this is the here's one of the trnas in + + + align:start position:0% +this is the here's one of the trnas in +yellow and its end is right there and + + align:start position:0% +yellow and its end is right there and + + + align:start position:0% +yellow and its end is right there and +there's the other TRNA and its end is + + align:start position:0% +there's the other TRNA and its end is + + + align:start position:0% +there's the other TRNA and its end is +right there so this corresponds to the + + align:start position:0% +right there so this corresponds to the + + + align:start position:0% +right there so this corresponds to the +point at which there's going to be an + + align:start position:0% +point at which there's going to be an + + + align:start position:0% +point at which there's going to be an +amino acid formed and it's going to be + + align:start position:0% +amino acid formed and it's going to be + + + align:start position:0% +amino acid formed and it's going to be +catalyze something's going to catalyze + + align:start position:0% +catalyze something's going to catalyze + + + align:start position:0% +catalyze something's going to catalyze +the formation of that Bond well the next + + align:start position:0% +the formation of that Bond well the next + + + align:start position:0% +the formation of that Bond well the next +picture sort of shows uh what happens if + + align:start position:0% +picture sort of shows uh what happens if + + + align:start position:0% +picture sort of shows uh what happens if +you pull that apart and what you'll see + + align:start position:0% +you pull that apart and what you'll see + + + align:start position:0% +you pull that apart and what you'll see +is that here's the end of one end of the + + align:start position:0% +is that here's the end of one end of the + + + align:start position:0% +is that here's the end of one end of the +TRNA there's the other end and there's + + align:start position:0% +TRNA there's the other end and there's + + + align:start position:0% +TRNA there's the other end and there's +nothing near it except for + + align:start position:0% +nothing near it except for + + + align:start position:0% +nothing near it except for +RNA so RNA is actually + + align:start position:0% +RNA so RNA is actually + + + align:start position:0% +RNA so RNA is actually +catalyzing the formation of the peptide + + align:start position:0% +catalyzing the formation of the peptide + + + align:start position:0% +catalyzing the formation of the peptide +bond another way to say + + align:start position:0% +bond another way to say + + + align:start position:0% +bond another way to say +that would be that the + + align:start position:0% +that would be that the + + + align:start position:0% +that would be that the +ribosome which is the protein + + align:start position:0% +ribosome which is the protein + + + align:start position:0% +ribosome which is the protein +synthesizing the factory is + + align:start position:0% +synthesizing the factory is + + + align:start position:0% +synthesizing the factory is +a + + align:start position:0% +a + + + align:start position:0% +a +ribos remember I said most of the + + align:start position:0% +ribos remember I said most of the + + + align:start position:0% +ribos remember I said most of the +chemical reactions that are that need + + align:start position:0% +chemical reactions that are that need + + + align:start position:0% +chemical reactions that are that need +catalysts are carried out out by + + align:start position:0% +catalysts are carried out out by + + + align:start position:0% +catalysts are carried out out by +proteins but there are a few that are + + align:start position:0% +proteins but there are a few that are + + + align:start position:0% +proteins but there are a few that are +carried out by by RNA where RNA is the + + align:start position:0% +carried out by by RNA where RNA is the + + + align:start position:0% +carried out by by RNA where RNA is the +Catalyst and + + align:start position:0% +Catalyst and + + + align:start position:0% +Catalyst and +remarkably the formation of the bond + + align:start position:0% +remarkably the formation of the bond + + + align:start position:0% +remarkably the formation of the bond +which is at the heart of protein which + + align:start position:0% +which is at the heart of protein which + + + align:start position:0% +which is at the heart of protein which +are so important for all life is + + align:start position:0% +are so important for all life is + + + align:start position:0% +are so important for all life is +character is is U catalyzed by protein + + align:start position:0% +character is is U catalyzed by protein + + + align:start position:0% +character is is U catalyzed by protein +if you look at what makes proteins what + + align:start position:0% +if you look at what makes proteins what + + + align:start position:0% +if you look at what makes proteins what +what do you see you see huge balls of + + align:start position:0% +what do you see you see huge balls of + + + align:start position:0% +what do you see you see huge balls of +RNA a messenger in our RNA threading + + align:start position:0% +RNA a messenger in our RNA threading + + + align:start position:0% +RNA a messenger in our RNA threading +through two trnas and the enzyme + + align:start position:0% +through two trnas and the enzyme + + + align:start position:0% +through two trnas and the enzyme +activity or the catalytic activi is + + align:start position:0% +activity or the catalytic activi is + + + align:start position:0% +activity or the catalytic activi is +encoded by the RNA as well as I said + + align:start position:0% +encoded by the RNA as well as I said + + + align:start position:0% +encoded by the RNA as well as I said +people think possibly there was an RNA + + align:start position:0% +people think possibly there was an RNA + + + align:start position:0% +people think possibly there was an RNA +world that preceded our present day + + align:start position:0% +world that preceded our present day + + + align:start position:0% +world that preceded our present day +world with DNA RNA and protein and who + + align:start position:0% +world with DNA RNA and protein and who + + + align:start position:0% +world with DNA RNA and protein and who +knows but this sort of look at a + + align:start position:0% +knows but this sort of look at a + + + align:start position:0% +knows but this sort of look at a +ribosome could at least make you see + + align:start position:0% +ribosome could at least make you see + + + align:start position:0% +ribosome could at least make you see +that that's a plausible explanation that + + align:start position:0% +that that's a plausible explanation that + + + align:start position:0% +that that's a plausible explanation that +RNA might have been running the show for + + align:start position:0% +RNA might have been running the show for + + + align:start position:0% +RNA might have been running the show for +a while before anything else got + + align:start position:0% +a while before anything else got + + + align:start position:0% +a while before anything else got +involved anyway we'll see you on Friday + + align:start position:0% + + + + align:start position:0% + +then \ No newline at end of file diff --git a/49Ro2zf9hAc.txt b/49Ro2zf9hAc.txt new file mode 100644 index 0000000000000000000000000000000000000000..2f7d340e1403cf0d61ec0bae6ef6147bb241d865 --- /dev/null +++ b/49Ro2zf9hAc.txt @@ -0,0 +1,10572 @@ +align:start position:0% + +okay so + + align:start position:0% +okay so + + + align:start position:0% +okay so +last time we + + align:start position:0% +last time we + + + align:start position:0% +last time we +were talking about sequences + + align:start position:0% + + + + align:start position:0% + +and i introduced the notion of a limit + + align:start position:0% +and i introduced the notion of a limit + + + align:start position:0% +and i introduced the notion of a limit +of a sequence um + + align:start position:0% +of a sequence um + + + align:start position:0% +of a sequence um +so we say that + + align:start position:0% +so we say that + + + align:start position:0% +so we say that +x n converges to x if for all epsilon + + align:start position:0% +x n converges to x if for all epsilon + + + align:start position:0% +x n converges to x if for all epsilon +positive there exists an m a natural + + align:start position:0% +positive there exists an m a natural + + + align:start position:0% +positive there exists an m a natural +number such that for all little n bigger + + align:start position:0% +number such that for all little n bigger + + + align:start position:0% +number such that for all little n bigger +than or equal to capital m we have x of + + align:start position:0% +than or equal to capital m we have x of + + + align:start position:0% +than or equal to capital m we have x of +n minus x is less than epsilon so what + + align:start position:0% +n minus x is less than epsilon so what + + + align:start position:0% +n minus x is less than epsilon so what +this definition says + + align:start position:0% +this definition says + + + align:start position:0% +this definition says +is that + + align:start position:0% +is that + + + align:start position:0% +is that +given any little bit of tolerance as + + align:start position:0% +given any little bit of tolerance as + + + align:start position:0% +given any little bit of tolerance as +long as i go far enough out in the + + align:start position:0% +long as i go far enough out in the + + + align:start position:0% +long as i go far enough out in the +sequence the entries are getting within + + align:start position:0% +sequence the entries are getting within + + + align:start position:0% +sequence the entries are getting within +that tolerance to x okay and when we + + align:start position:0% +that tolerance to x okay and when we + + + align:start position:0% +that tolerance to x okay and when we +when x n converges to x we'll write x is + + align:start position:0% +when x n converges to x we'll write x is + + + align:start position:0% +when x n converges to x we'll write x is +equal to the limit as n goes to infinity + + align:start position:0% +equal to the limit as n goes to infinity + + + align:start position:0% +equal to the limit as n goes to infinity +of x sub n or + + align:start position:0% +of x sub n or + + + align:start position:0% +of x sub n or +using this notation x sub n + + align:start position:0% +using this notation x sub n + + + align:start position:0% +using this notation x sub n +arrow x + + align:start position:0% +arrow x + + + align:start position:0% +arrow x +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and so i've said before that if you ever + + align:start position:0% +and so i've said before that if you ever + + + align:start position:0% +and so i've said before that if you ever +have + + align:start position:0% +have + + + align:start position:0% +have +a reasonable + + align:start position:0% +a reasonable + + + align:start position:0% +a reasonable +reasonably complicated or interesting + + align:start position:0% +reasonably complicated or interesting + + + align:start position:0% +reasonably complicated or interesting +definition you should try to come up + + align:start position:0% +definition you should try to come up + + + align:start position:0% +definition you should try to come up +with examples + + align:start position:0% +with examples + + + align:start position:0% +with examples +and negate it so + + align:start position:0% + + + + align:start position:0% + +the end of last time we saw a few + + align:start position:0% +the end of last time we saw a few + + + align:start position:0% +the end of last time we saw a few +examples of + + align:start position:0% +examples of + + + align:start position:0% +examples of +at least one example of a convergent + + align:start position:0% +at least one example of a convergent + + + align:start position:0% +at least one example of a convergent +sequence + + align:start position:0% +sequence + + + align:start position:0% +sequence +um let's negate this uh definition + + align:start position:0% +um let's negate this uh definition + + + align:start position:0% +um let's negate this uh definition +because then we'll also come up with an + + align:start position:0% +because then we'll also come up with an + + + align:start position:0% +because then we'll also come up with an +example of a sequence which does not + + align:start position:0% +example of a sequence which does not + + + align:start position:0% +example of a sequence which does not +converge + + align:start position:0% +converge + + + align:start position:0% +converge +and so the negation of this uh + + align:start position:0% + + + + align:start position:0% + +definition is that xn + + align:start position:0% + + + + align:start position:0% + +does not converge to x what does this + + align:start position:0% +does not converge to x what does this + + + align:start position:0% +does not converge to x what does this +mean so this is the actual negation part + + align:start position:0% +mean so this is the actual negation part + + + align:start position:0% +mean so this is the actual negation part +if there exists + + align:start position:0% +if there exists + + + align:start position:0% +if there exists +an epsilon positive so whenever we + + align:start position:0% +an epsilon positive so whenever we + + + align:start position:0% +an epsilon positive so whenever we +negate a4 all it becomes there exists + + align:start position:0% +negate a4 all it becomes there exists + + + align:start position:0% +negate a4 all it becomes there exists +and whenever we negate there exists it + + align:start position:0% +and whenever we negate there exists it + + + align:start position:0% +and whenever we negate there exists it +becomes a for all + + align:start position:0% +becomes a for all + + + align:start position:0% +becomes a for all +so there exists some bad epsilon zero + + align:start position:0% +so there exists some bad epsilon zero + + + align:start position:0% +so there exists some bad epsilon zero +positive + + align:start position:0% +positive + + + align:start position:0% +positive +such that + + align:start position:0% +such that + + + align:start position:0% +such that +for all + + align:start position:0% +for all + + + align:start position:0% +for all +natural numbers in + + align:start position:0% + + + + align:start position:0% + +there exists + + align:start position:0% +there exists + + + align:start position:0% +there exists +in n bigger than or equal to m + + align:start position:0% +in n bigger than or equal to m + + + align:start position:0% +in n bigger than or equal to m +such that + + align:start position:0% + + + + align:start position:0% + +x n minus x is bigger than or equal to + + align:start position:0% +x n minus x is bigger than or equal to + + + align:start position:0% +x n minus x is bigger than or equal to +this bad + + align:start position:0% +this bad + + + align:start position:0% +this bad +epsilon naught and distance + + align:start position:0% +epsilon naught and distance + + + align:start position:0% +epsilon naught and distance +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so we have a picture that goes along + + align:start position:0% +so we have a picture that goes along + + + align:start position:0% +so we have a picture that goes along +with convergence we can have a picture + + align:start position:0% +with convergence we can have a picture + + + align:start position:0% +with convergence we can have a picture +that goes along with + + align:start position:0% +that goes along with + + + align:start position:0% +that goes along with +a sequence not converging to x so this + + align:start position:0% +a sequence not converging to x so this + + + align:start position:0% +a sequence not converging to x so this +means if i + + align:start position:0% + + + + align:start position:0% + +go out within this bad epsilon knot + + align:start position:0% +go out within this bad epsilon knot + + + align:start position:0% +go out within this bad epsilon knot +and if i go + + align:start position:0% +and if i go + + + align:start position:0% +and if i go +arbitrarily out in the sequence i can + + align:start position:0% +arbitrarily out in the sequence i can + + + align:start position:0% +arbitrarily out in the sequence i can +always find an element x sub n which is + + align:start position:0% + + + + align:start position:0% + +not in that interval + + align:start position:0% +not in that interval + + + align:start position:0% +not in that interval +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and we use this negation to prove a + + align:start position:0% +and we use this negation to prove a + + + align:start position:0% +and we use this negation to prove a +certain sequence does not converge to x + + align:start position:0% +certain sequence does not converge to x + + + align:start position:0% +certain sequence does not converge to x +but let's go back + + align:start position:0% +but let's go back + + + align:start position:0% +but let's go back +to another example of a sequence which + + align:start position:0% +to another example of a sequence which + + + align:start position:0% +to another example of a sequence which +does converge + + align:start position:0% +does converge + + + align:start position:0% +does converge +so + + align:start position:0% + + + + align:start position:0% + +zero + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +again how does the proof go you have to + + align:start position:0% +again how does the proof go you have to + + + align:start position:0% +again how does the proof go you have to +verify + + align:start position:0% +verify + + + align:start position:0% +verify +the definition of the limit i mean + + align:start position:0% +the definition of the limit i mean + + + align:start position:0% +the definition of the limit i mean +there's nothing else that we have to use + + align:start position:0% +there's nothing else that we have to use + + + align:start position:0% +there's nothing else that we have to use +right now + + align:start position:0% +right now + + + align:start position:0% +right now +so let epsilon be positive + + align:start position:0% +so let epsilon be positive + + + align:start position:0% +so let epsilon be positive +and now off to the side over here i'm + + align:start position:0% +and now off to the side over here i'm + + + align:start position:0% +and now off to the side over here i'm +going to do a little bit of work + + align:start position:0% + + + + align:start position:0% + +to show you how exactly + + align:start position:0% +to show you how exactly + + + align:start position:0% +to show you how exactly +in practice one would find such a + + align:start position:0% +in practice one would find such a + + + align:start position:0% +in practice one would find such a +capital m or choose a capital m to get + + align:start position:0% +capital m or choose a capital m to get + + + align:start position:0% +capital m or choose a capital m to get +that um 1 over n squared plus 30 n plus + + align:start position:0% +that um 1 over n squared plus 30 n plus + + + align:start position:0% +that um 1 over n squared plus 30 n plus +1 would be less than epsilon + + align:start position:0% +1 would be less than epsilon + + + align:start position:0% +1 would be less than epsilon +for n bigger than or equal to capital m + + align:start position:0% +for n bigger than or equal to capital m + + + align:start position:0% +for n bigger than or equal to capital m +so + + align:start position:0% +so + + + align:start position:0% +so +typically how this works is + + align:start position:0% +typically how this works is + + + align:start position:0% +typically how this works is +unlike in calculus where you have some + + align:start position:0% +unlike in calculus where you have some + + + align:start position:0% +unlike in calculus where you have some +inequality that you want to + + align:start position:0% +inequality that you want to + + + align:start position:0% +inequality that you want to +get and then you solve for n + + align:start position:0% +get and then you solve for n + + + align:start position:0% +get and then you solve for n +in analysis what's great is that you can + + align:start position:0% +in analysis what's great is that you can + + + align:start position:0% +in analysis what's great is that you can +replace that + + align:start position:0% +replace that + + + align:start position:0% +replace that +thing you want to make small by + + align:start position:0% +thing you want to make small by + + + align:start position:0% +thing you want to make small by +something simpler and then solve that + + align:start position:0% +something simpler and then solve that + + + align:start position:0% +something simpler and then solve that +inequality what do i mean so i want + + align:start position:0% + + + + align:start position:0% + +what do i want to do i want to find m + + align:start position:0% +what do i want to do i want to find m + + + align:start position:0% +what do i want to do i want to find m +so that if + + align:start position:0% +so that if + + + align:start position:0% +so that if +m is bigger than or equal to m then + + align:start position:0% +m is bigger than or equal to m then + + + align:start position:0% +m is bigger than or equal to m then +so i'm saying the limit is 0 so i want + + align:start position:0% +so i'm saying the limit is 0 so i want + + + align:start position:0% +so i'm saying the limit is 0 so i want +to show + + align:start position:0% +to show + + + align:start position:0% +to show +1 over n squared plus 30 n + + align:start position:0% +1 over n squared plus 30 n + + + align:start position:0% +1 over n squared plus 30 n +plus 1 + + align:start position:0% +plus 1 + + + align:start position:0% +plus 1 +is less than epsilon okay + + align:start position:0% +is less than epsilon okay + + + align:start position:0% +is less than epsilon okay +now i could try to solve this inequality + + align:start position:0% +now i could try to solve this inequality + + + align:start position:0% +now i could try to solve this inequality +for n + + align:start position:0% +for n + + + align:start position:0% +for n +but this is a quadratic function and + + align:start position:0% +but this is a quadratic function and + + + align:start position:0% +but this is a quadratic function and +imagine i put a + + align:start position:0% +imagine i put a + + + align:start position:0% +imagine i put a +20 there + + align:start position:0% +20 there + + + align:start position:0% +20 there +so i can't exactly solve exactly for n + + align:start position:0% +so i can't exactly solve exactly for n + + + align:start position:0% +so i can't exactly solve exactly for n +uh to guarantee this + + align:start position:0% +uh to guarantee this + + + align:start position:0% +uh to guarantee this +but + + align:start position:0% +but + + + align:start position:0% +but +what's great about analysis is that i + + align:start position:0% +what's great about analysis is that i + + + align:start position:0% +what's great about analysis is that i +just + + align:start position:0% +just + + + align:start position:0% +just +i don't have to work + + align:start position:0% +i don't have to work + + + align:start position:0% +i don't have to work +that hard + + align:start position:0% +that hard + + + align:start position:0% +that hard +i could start with this thing which i + + align:start position:0% +i could start with this thing which i + + + align:start position:0% +i could start with this thing which i +want to bound by epsilon + + align:start position:0% +want to bound by epsilon + + + align:start position:0% +want to bound by epsilon +replace it by something bigger and then + + align:start position:0% +replace it by something bigger and then + + + align:start position:0% +replace it by something bigger and then +find capital m so that that bigger thing + + align:start position:0% +find capital m so that that bigger thing + + + align:start position:0% +find capital m so that that bigger thing +is less than epsilon so what do i mean + + align:start position:0% +is less than epsilon so what do i mean + + + align:start position:0% +is less than epsilon so what do i mean +so let's start with this thing one over + + align:start position:0% +so let's start with this thing one over + + + align:start position:0% +so let's start with this thing one over +n squared + + align:start position:0% +n squared + + + align:start position:0% +n squared +plus 30 n + + align:start position:0% +plus 30 n + + + align:start position:0% +plus 30 n +plus one + + align:start position:0% + + + + align:start position:0% + +so this one is only making things bigger + + align:start position:0% +so this one is only making things bigger + + + align:start position:0% +so this one is only making things bigger +i'm going to do this very slowly + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +this is less than or equal to this + + align:start position:0% +this is less than or equal to this + + + align:start position:0% +this is less than or equal to this +because + + align:start position:0% +because + + + align:start position:0% +because +for this i've just added 1 to the + + align:start position:0% +for this i've just added 1 to the + + + align:start position:0% +for this i've just added 1 to the +denominator and 1 over n squared plus 30 + + align:start position:0% +denominator and 1 over n squared plus 30 + + + align:start position:0% +denominator and 1 over n squared plus 30 +n this certainly looks a little bit + + align:start position:0% +n this certainly looks a little bit + + + align:start position:0% +n this certainly looks a little bit +simpler to solve for n less than epsilon + + align:start position:0% +simpler to solve for n less than epsilon + + + align:start position:0% +simpler to solve for n less than epsilon +but i can make it even simpler by + + align:start position:0% +but i can make it even simpler by + + + align:start position:0% +but i can make it even simpler by +dropping the n squared because n squared + + align:start position:0% +dropping the n squared because n squared + + + align:start position:0% +dropping the n squared because n squared +is positive so that's only making the + + align:start position:0% +is positive so that's only making the + + + align:start position:0% +is positive so that's only making the +bottom bigger + + align:start position:0% + + + + align:start position:0% + +okay so i have 1 over 30 n and this is + + align:start position:0% +okay so i have 1 over 30 n and this is + + + align:start position:0% +okay so i have 1 over 30 n and this is +certainly less than or equal to 1 over n + + align:start position:0% +certainly less than or equal to 1 over n + + + align:start position:0% +certainly less than or equal to 1 over n +all right so + + align:start position:0% +all right so + + + align:start position:0% +all right so +what does this + + align:start position:0% +what does this + + + align:start position:0% +what does this +computation show this shows that + + align:start position:0% + + + + align:start position:0% + +if one over n is less than epsilon then + + align:start position:0% +if one over n is less than epsilon then + + + align:start position:0% +if one over n is less than epsilon then +this implies that + + align:start position:0% +this implies that + + + align:start position:0% +this implies that +one over n squared plus 30 n + + align:start position:0% +one over n squared plus 30 n + + + align:start position:0% +one over n squared plus 30 n +plus one is less than epsilon + + align:start position:0% +plus one is less than epsilon + + + align:start position:0% +plus one is less than epsilon +okay + + align:start position:0% +okay + + + align:start position:0% +okay +all right if this thing is less than + + align:start position:0% +all right if this thing is less than + + + align:start position:0% +all right if this thing is less than +epsilon then by this string of + + align:start position:0% +epsilon then by this string of + + + align:start position:0% +epsilon then by this string of +inequalities this thing will be less + + align:start position:0% +inequalities this thing will be less + + + align:start position:0% +inequalities this thing will be less +than epsilon so we choose capital m + + align:start position:0% +than epsilon so we choose capital m + + + align:start position:0% +than epsilon so we choose capital m +so that we get this + + align:start position:0% +so that we get this + + + align:start position:0% +so that we get this +okay + + align:start position:0% +okay + + + align:start position:0% +okay +now when we actually write the proof + + align:start position:0% +now when we actually write the proof + + + align:start position:0% +now when we actually write the proof +it'll look something like this but the + + align:start position:0% +it'll look something like this but the + + + align:start position:0% +it'll look something like this but the +you know actual style of the proof is is + + align:start position:0% +you know actual style of the proof is is + + + align:start position:0% +you know actual style of the proof is is +a little bit + + align:start position:0% +a little bit + + + align:start position:0% +a little bit +um + + align:start position:0% +um + + + align:start position:0% +um +different + + align:start position:0% +different + + + align:start position:0% +different +and if you didn't see this it would just + + align:start position:0% +and if you didn't see this it would just + + + align:start position:0% +and if you didn't see this it would just +seem like i pulled this capital m out of + + align:start position:0% +seem like i pulled this capital m out of + + + align:start position:0% +seem like i pulled this capital m out of +nowhere + + align:start position:0% +nowhere + + + align:start position:0% +nowhere +um + + align:start position:0% +um + + + align:start position:0% +um +but this is the thinking that goes + + align:start position:0% +but this is the thinking that goes + + + align:start position:0% +but this is the thinking that goes +behind it so let epsilon be positive now + + align:start position:0% +behind it so let epsilon be positive now + + + align:start position:0% +behind it so let epsilon be positive now +i'll tell you how to choose capital m + + align:start position:0% + + + + align:start position:0% + +choose m + + align:start position:0% +choose m + + + align:start position:0% +choose m +natural number + + align:start position:0% +natural number + + + align:start position:0% +natural number +so that so we wanted for all n bigger + + align:start position:0% +so that so we wanted for all n bigger + + + align:start position:0% +so that so we wanted for all n bigger +than or equal to capital m one over n is + + align:start position:0% +than or equal to capital m one over n is + + + align:start position:0% +than or equal to capital m one over n is +less than epsilon so + + align:start position:0% +less than epsilon so + + + align:start position:0% +less than epsilon so +uh this will certainly be true if n is + + align:start position:0% +uh this will certainly be true if n is + + + align:start position:0% +uh this will certainly be true if n is +bigger than or equal to m capital m so + + align:start position:0% +bigger than or equal to m capital m so + + + align:start position:0% +bigger than or equal to m capital m so +that one over capital m is less than + + align:start position:0% +that one over capital m is less than + + + align:start position:0% +that one over capital m is less than +epsilon + + align:start position:0% + + + + align:start position:0% + +and the reason we can choose capital m + + align:start position:0% +and the reason we can choose capital m + + + align:start position:0% +and the reason we can choose capital m +like this again where is this coming + + align:start position:0% +like this again where is this coming + + + align:start position:0% +like this again where is this coming +from it's coming from the archimedean uh + + align:start position:0% +from it's coming from the archimedean uh + + + align:start position:0% +from it's coming from the archimedean uh +property of the real numbers + + align:start position:0% +property of the real numbers + + + align:start position:0% +property of the real numbers +um + + align:start position:0% +um + + + align:start position:0% +um +okay so + + align:start position:0% +okay so + + + align:start position:0% +okay so +we've chosen capital m now we need to + + align:start position:0% +we've chosen capital m now we need to + + + align:start position:0% +we've chosen capital m now we need to +show that this capital m works + + align:start position:0% + + + + align:start position:0% + +then for all + + align:start position:0% +then for all + + + align:start position:0% +then for all +n + + align:start position:0% +n + + + align:start position:0% +n +bigger than or equal to capital m + + align:start position:0% +bigger than or equal to capital m + + + align:start position:0% +bigger than or equal to capital m +if i look at + + align:start position:0% +if i look at + + + align:start position:0% +if i look at +1 over n squared plus 30 n + + align:start position:0% +1 over n squared plus 30 n + + + align:start position:0% +1 over n squared plus 30 n +plus 1 minus 0 my proposed limit + + align:start position:0% +plus 1 minus 0 my proposed limit + + + align:start position:0% +plus 1 minus 0 my proposed limit +this is equal to 1 over n squared + + align:start position:0% + + + + align:start position:0% + +plus 1. + + align:start position:0% +plus 1. + + + align:start position:0% +plus 1. +and this is less than or equal to if i + + align:start position:0% +and this is less than or equal to if i + + + align:start position:0% +and this is less than or equal to if i +drop n squared and 1 + + align:start position:0% +drop n squared and 1 + + + align:start position:0% +drop n squared and 1 +30 n which is less than or equal to 1 + + align:start position:0% +30 n which is less than or equal to 1 + + + align:start position:0% +30 n which is less than or equal to 1 +over n + + align:start position:0% +over n + + + align:start position:0% +over n +which is less than or equal to 1 over + + align:start position:0% +which is less than or equal to 1 over + + + align:start position:0% +which is less than or equal to 1 over +capital m which is less than epsilon + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +okay um + + align:start position:0% + + + + align:start position:0% + +so so something of a non-example + + align:start position:0% +so so something of a non-example + + + align:start position:0% +so so something of a non-example +um let's show that the sequence + + align:start position:0% +um let's show that the sequence + + + align:start position:0% +um let's show that the sequence +minus one to the n + + align:start position:0% +minus one to the n + + + align:start position:0% +minus one to the n +uh + + align:start position:0% +uh + + + align:start position:0% +uh +dnc does not converge + + align:start position:0% +dnc does not converge + + + align:start position:0% +dnc does not converge +not democratic national committee + + align:start position:0% + + + + align:start position:0% + +does not converge + + align:start position:0% +does not converge + + + align:start position:0% +does not converge +so + + align:start position:0% +so + + + align:start position:0% +so +so this is just the sequence um + + align:start position:0% +so this is just the sequence um + + + align:start position:0% +so this is just the sequence um +minus one one minus one one minus one + + align:start position:0% +minus one one minus one one minus one + + + align:start position:0% +minus one one minus one one minus one +and so on + + align:start position:0% +and so on + + + align:start position:0% +and so on +okay so we have to show it does not + + align:start position:0% +okay so we have to show it does not + + + align:start position:0% +okay so we have to show it does not +converge meaning for every x and r we'll + + align:start position:0% +converge meaning for every x and r we'll + + + align:start position:0% +converge meaning for every x and r we'll +show that x n does not converge to x + + align:start position:0% +show that x n does not converge to x + + + align:start position:0% +show that x n does not converge to x +using the + + align:start position:0% +using the + + + align:start position:0% +using the +negation of the definition all right + + align:start position:0% +negation of the definition all right + + + align:start position:0% +negation of the definition all right +so + + align:start position:0% + + + + align:start position:0% + +proof so + + align:start position:0% + + + + align:start position:0% + +let x be an r and what do we want to + + align:start position:0% +let x be an r and what do we want to + + + align:start position:0% +let x be an r and what do we want to +show + + align:start position:0% + + + + align:start position:0% + +minus 1 to the n + + align:start position:0% + + + + align:start position:0% + +does not converge + + align:start position:0% + + + + align:start position:0% + +to x + + align:start position:0% + + + + align:start position:0% + +okay and we'll use this definition so + + align:start position:0% +okay and we'll use this definition so + + + align:start position:0% +okay and we'll use this definition so +uh + + align:start position:0% +uh + + + align:start position:0% +uh +this definition means we need to find a + + align:start position:0% +this definition means we need to find a + + + align:start position:0% +this definition means we need to find a +bad epsilon naught + + align:start position:0% +bad epsilon naught + + + align:start position:0% +bad epsilon naught +okay + + align:start position:0% + + + + align:start position:0% + +and here's the the kind of thinking that + + align:start position:0% +and here's the the kind of thinking that + + + align:start position:0% +and here's the the kind of thinking that +goes along with this + + align:start position:0% +goes along with this + + + align:start position:0% +goes along with this +there's one there's minus one + + align:start position:0% +there's one there's minus one + + + align:start position:0% +there's one there's minus one +this sequence just keeps alternating + + align:start position:0% +this sequence just keeps alternating + + + align:start position:0% +this sequence just keeps alternating +right so so intuitively there's no way + + align:start position:0% +right so so intuitively there's no way + + + align:start position:0% +right so so intuitively there's no way +that + + align:start position:0% +that + + + align:start position:0% +that +uh every element of the sequence can be + + align:start position:0% +uh every element of the sequence can be + + + align:start position:0% +uh every element of the sequence can be +getting or every entry in the sequence + + align:start position:0% +getting or every entry in the sequence + + + align:start position:0% +getting or every entry in the sequence +can be getting close to some single x + + align:start position:0% +can be getting close to some single x + + + align:start position:0% +can be getting close to some single x +so what's the idea the idea is that the + + align:start position:0% +so what's the idea the idea is that the + + + align:start position:0% +so what's the idea the idea is that the +distance between + + align:start position:0% +distance between + + + align:start position:0% +distance between +these two guys + + align:start position:0% +these two guys + + + align:start position:0% +these two guys +is always two + + align:start position:0% +is always two + + + align:start position:0% +is always two +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so somehow + + align:start position:0% +so somehow + + + align:start position:0% +so somehow +um the distance between + + align:start position:0% +um the distance between + + + align:start position:0% +um the distance between +uh + + align:start position:0% +uh + + + align:start position:0% +uh +every entry or + + align:start position:0% +every entry or + + + align:start position:0% +every entry or +basically some entry has to be within + + align:start position:0% +basically some entry has to be within + + + align:start position:0% +basically some entry has to be within +distance uh if it's if this is within + + align:start position:0% +distance uh if it's if this is within + + + align:start position:0% +distance uh if it's if this is within +distance one + + align:start position:0% +distance one + + + align:start position:0% +distance one +say to a given x + + align:start position:0% +say to a given x + + + align:start position:0% +say to a given x +then this will be greater than or equal + + align:start position:0% +then this will be greater than or equal + + + align:start position:0% +then this will be greater than or equal +to one in distance to x + + align:start position:0% +to one in distance to x + + + align:start position:0% +to one in distance to x +okay so you can imagine x is over here + + align:start position:0% +okay so you can imagine x is over here + + + align:start position:0% +okay so you can imagine x is over here +minus one is within distance one to x + + align:start position:0% +minus one is within distance one to x + + + align:start position:0% +minus one is within distance one to x +but then one would be + + align:start position:0% +but then one would be + + + align:start position:0% +but then one would be +greater than distance one + + align:start position:0% +greater than distance one + + + align:start position:0% +greater than distance one +uh to x + + align:start position:0% +uh to x + + + align:start position:0% +uh to x +okay so our bad epsilon naught + + align:start position:0% +okay so our bad epsilon naught + + + align:start position:0% +okay so our bad epsilon naught +was going to be one as we'll see + + align:start position:0% + + + + align:start position:0% + +let epsilon not equals one that's our + + align:start position:0% +let epsilon not equals one that's our + + + align:start position:0% +let epsilon not equals one that's our +bad epsilon so now we have to show for + + align:start position:0% +bad epsilon so now we have to show for + + + align:start position:0% +bad epsilon so now we have to show for +all capital m and natural number there + + align:start position:0% +all capital m and natural number there + + + align:start position:0% +all capital m and natural number there +exists a little n bigger than or equal + + align:start position:0% +exists a little n bigger than or equal + + + align:start position:0% +exists a little n bigger than or equal +to capital m so that + + align:start position:0% +to capital m so that + + + align:start position:0% +to capital m so that +um + + align:start position:0% +um + + + align:start position:0% +um +we have that inequality so + + align:start position:0% +we have that inequality so + + + align:start position:0% +we have that inequality so +let m be a natural + + align:start position:0% + + + + align:start position:0% + +number then what do we see + + align:start position:0% + + + + align:start position:0% + +uh so then this says there exists an n + + align:start position:0% +uh so then this says there exists an n + + + align:start position:0% +uh so then this says there exists an n +greater than or equal to capital m + + align:start position:0% + + + + align:start position:0% + +and i will show that n is in fact either + + align:start position:0% +and i will show that n is in fact either + + + align:start position:0% +and i will show that n is in fact either +capital m or capital n plus one + + align:start position:0% + + + + align:start position:0% + +then two + + align:start position:0% +then two + + + align:start position:0% +then two +which is + + align:start position:0% + + + + align:start position:0% + +the distance between + + align:start position:0% +the distance between + + + align:start position:0% +the distance between +minus one to the m and minus 1 to the n + + align:start position:0% +minus one to the m and minus 1 to the n + + + align:start position:0% +minus one to the m and minus 1 to the n +plus 1 + + align:start position:0% + + + + align:start position:0% + +is less than or equal to now using the + + align:start position:0% +is less than or equal to now using the + + + align:start position:0% +is less than or equal to now using the +triangle inequality i add and subtract x + + align:start position:0% +triangle inequality i add and subtract x + + + align:start position:0% +triangle inequality i add and subtract x +and then use the triangle inequality + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so i have the sum of two numbers is + + align:start position:0% +so i have the sum of two numbers is + + + align:start position:0% +so i have the sum of two numbers is +bigger than or equal to two + + align:start position:0% +bigger than or equal to two + + + align:start position:0% +bigger than or equal to two +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and the only way that can happen is if + + align:start position:0% +and the only way that can happen is if + + + align:start position:0% +and the only way that can happen is if +one of these numbers is bigger than or + + align:start position:0% +one of these numbers is bigger than or + + + align:start position:0% +one of these numbers is bigger than or +equal to one if both of these numbers + + align:start position:0% +equal to one if both of these numbers + + + align:start position:0% +equal to one if both of these numbers +are less than one + + align:start position:0% +are less than one + + + align:start position:0% +are less than one +then the sum is less than two and i + + align:start position:0% +then the sum is less than two and i + + + align:start position:0% +then the sum is less than two and i +would have two is less than two that's + + align:start position:0% +would have two is less than two that's + + + align:start position:0% +would have two is less than two that's +not possible so one of these numbers has + + align:start position:0% +not possible so one of these numbers has + + + align:start position:0% +not possible so one of these numbers has +to be bigger than or equal to one + + align:start position:0% + + + + align:start position:0% + +and therefore i could take n equal to + + align:start position:0% +and therefore i could take n equal to + + + align:start position:0% +and therefore i could take n equal to +capital m uh if this is bigger than or + + align:start position:0% +capital m uh if this is bigger than or + + + align:start position:0% +capital m uh if this is bigger than or +equal to one or if this is bigger than + + align:start position:0% +equal to one or if this is bigger than + + + align:start position:0% +equal to one or if this is bigger than +or equal to one i k i take little n to + + align:start position:0% +or equal to one i k i take little n to + + + align:start position:0% +or equal to one i k i take little n to +be capital n plus one so that's the end + + align:start position:0% +be capital n plus one so that's the end + + + align:start position:0% +be capital n plus one so that's the end +of that + + align:start position:0% + + + + align:start position:0% + +alrighty so that's uh + + align:start position:0% +alrighty so that's uh + + + align:start position:0% +alrighty so that's uh +that's good for + + align:start position:0% + + + + align:start position:0% + +examples for now + + align:start position:0% +examples for now + + + align:start position:0% +examples for now +let's prove a + + align:start position:0% +let's prove a + + + align:start position:0% +let's prove a +general theorem about convergent + + align:start position:0% +general theorem about convergent + + + align:start position:0% +general theorem about convergent +sequences + + align:start position:0% +sequences + + + align:start position:0% +sequences +namely that if i have a convergent + + align:start position:0% +namely that if i have a convergent + + + align:start position:0% +namely that if i have a convergent +sequence then it's bounded + + align:start position:0% + + + + align:start position:0% + +and let me just give you a + + align:start position:0% + + + + align:start position:0% + +quick reminder + + align:start position:0% +quick reminder + + + align:start position:0% +quick reminder +about what being bounded means for a + + align:start position:0% +about what being bounded means for a + + + align:start position:0% +about what being bounded means for a +sequence + + align:start position:0% + + + + align:start position:0% + +i.e + + align:start position:0% +i.e + + + align:start position:0% +i.e +exists some number such that + + align:start position:0% +exists some number such that + + + align:start position:0% +exists some number such that +for all n + + align:start position:0% +for all n + + + align:start position:0% +for all n +x n is less than or equal to capital b + + align:start position:0% +x n is less than or equal to capital b + + + align:start position:0% +x n is less than or equal to capital b +okay + + align:start position:0% +okay + + + align:start position:0% +okay +now as + + align:start position:0% +now as + + + align:start position:0% +now as +um beginning students of math + + align:start position:0% + + + + align:start position:0% + +you know + + align:start position:0% +you know + + + align:start position:0% +you know +what types of questions should we start + + align:start position:0% +what types of questions should we start + + + align:start position:0% +what types of questions should we start +asking ourselves + + align:start position:0% + + + + align:start position:0% + +one of those so one of the types + + align:start position:0% +one of those so one of the types + + + align:start position:0% +one of those so one of the types +or a type of question that we should ask + + align:start position:0% +or a type of question that we should ask + + + align:start position:0% +or a type of question that we should ask +when we come across a theorem + + align:start position:0% +when we come across a theorem + + + align:start position:0% +when we come across a theorem +that + + align:start position:0% +that + + + align:start position:0% +that +is + + align:start position:0% +is + + + align:start position:0% +is +you know a one-way street meaning if + + align:start position:0% +you know a one-way street meaning if + + + align:start position:0% +you know a one-way street meaning if +something happens and something else + + align:start position:0% +something happens and something else + + + align:start position:0% +something happens and something else +happens + + align:start position:0% +happens + + + align:start position:0% +happens +is does the converse hold namely if i + + align:start position:0% +is does the converse hold namely if i + + + align:start position:0% +is does the converse hold namely if i +assume x sub n is a bounded sequence + + align:start position:0% +assume x sub n is a bounded sequence + + + align:start position:0% +assume x sub n is a bounded sequence +does this imply that xn is convergent + + align:start position:0% +does this imply that xn is convergent + + + align:start position:0% +does this imply that xn is convergent +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so if somebody if you ever hear the + + align:start position:0% +so if somebody if you ever hear the + + + align:start position:0% +so if somebody if you ever hear the +words does the converse hold that's what + + align:start position:0% +words does the converse hold that's what + + + align:start position:0% +words does the converse hold that's what +they mean + + align:start position:0% +they mean + + + align:start position:0% +they mean +now for this statement this is false + + align:start position:0% +now for this statement this is false + + + align:start position:0% +now for this statement this is false +if xn is bounded implies xn is + + align:start position:0% +if xn is bounded implies xn is + + + align:start position:0% +if xn is bounded implies xn is +convergent that's false because we have + + align:start position:0% +convergent that's false because we have + + + align:start position:0% +convergent that's false because we have +an example right there of a bounded + + align:start position:0% +an example right there of a bounded + + + align:start position:0% +an example right there of a bounded +sequence + + align:start position:0% +sequence + + + align:start position:0% +sequence +this sequence here minus 1 to the n is + + align:start position:0% +this sequence here minus 1 to the n is + + + align:start position:0% +this sequence here minus 1 to the n is +bounded since + + align:start position:0% + + + + align:start position:0% + +i mean an absolute value this equals 1 + + align:start position:0% +i mean an absolute value this equals 1 + + + align:start position:0% +i mean an absolute value this equals 1 +for all n so we could take b equals 1. + + align:start position:0% +for all n so we could take b equals 1. + + + align:start position:0% +for all n so we could take b equals 1. +so minus one to the n is a bounded + + align:start position:0% +so minus one to the n is a bounded + + + align:start position:0% +so minus one to the n is a bounded +sequence which is not convergent so the + + align:start position:0% +sequence which is not convergent so the + + + align:start position:0% +sequence which is not convergent so the +converse does not hold + + align:start position:0% +converse does not hold + + + align:start position:0% +converse does not hold +okay so let's prove + + align:start position:0% +okay so let's prove + + + align:start position:0% +okay so let's prove +the theorem and let me draw + + align:start position:0% + + + + align:start position:0% + +a little picture to go along with it + + align:start position:0% +a little picture to go along with it + + + align:start position:0% +a little picture to go along with it +of kind of what's going on + + align:start position:0% +of kind of what's going on + + + align:start position:0% +of kind of what's going on +um so here's zero + + align:start position:0% +um so here's zero + + + align:start position:0% +um so here's zero +let's imagine + + align:start position:0% +let's imagine + + + align:start position:0% +let's imagine +let me make this picture a little bit + + align:start position:0% +let me make this picture a little bit + + + align:start position:0% +let me make this picture a little bit +bigger + + align:start position:0% + + + + align:start position:0% + +before i go into the proof + + align:start position:0% + + + + align:start position:0% + +so let x be the limit + + align:start position:0% + + + + align:start position:0% + +so this is not the proof yet this is + + align:start position:0% +so this is not the proof yet this is + + + align:start position:0% +so this is not the proof yet this is +just uh + + align:start position:0% +just uh + + + align:start position:0% +just uh +more discussion + + align:start position:0% + + + + align:start position:0% + +so if this x sub n is converging to x + + align:start position:0% +so if this x sub n is converging to x + + + align:start position:0% +so if this x sub n is converging to x +then + + align:start position:0% +then + + + align:start position:0% +then +let's say i go out distance 1 + + align:start position:0% +let's say i go out distance 1 + + + align:start position:0% +let's say i go out distance 1 +to x + + align:start position:0% +to x + + + align:start position:0% +to x +then all of the x of n's eventually have + + align:start position:0% +then all of the x of n's eventually have + + + align:start position:0% +then all of the x of n's eventually have +to land in + + align:start position:0% +to land in + + + align:start position:0% +to land in +this strip here + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +x sub n + + align:start position:0% +x sub n + + + align:start position:0% +x sub n +and bigger than or equal to some capital + + align:start position:0% +and bigger than or equal to some capital + + + align:start position:0% +and bigger than or equal to some capital +m + + align:start position:0% +m + + + align:start position:0% +m +okay + + align:start position:0% + + + + align:start position:0% + +so i know that they're all within + + align:start position:0% +so i know that they're all within + + + align:start position:0% +so i know that they're all within +distance one to x so an absolute value + + align:start position:0% +distance one to x so an absolute value + + + align:start position:0% +distance one to x so an absolute value +they'd be bounded by + + align:start position:0% +they'd be bounded by + + + align:start position:0% +they'd be bounded by +uh + + align:start position:0% +uh + + + align:start position:0% +uh +let's say for this picture it'd be x + + align:start position:0% +let's say for this picture it'd be x + + + align:start position:0% +let's say for this picture it'd be x +plus one but um if this was over there + + align:start position:0% +plus one but um if this was over there + + + align:start position:0% +plus one but um if this was over there +capital it would be the absolute value + + align:start position:0% +capital it would be the absolute value + + + align:start position:0% +capital it would be the absolute value +of x plus one + + align:start position:0% +of x plus one + + + align:start position:0% +of x plus one +so that takes care of all x sub n's with + + align:start position:0% +so that takes care of all x sub n's with + + + align:start position:0% +so that takes care of all x sub n's with +n bigger than or equal to m and then + + align:start position:0% +n bigger than or equal to m and then + + + align:start position:0% +n bigger than or equal to m and then +there's only finitely many + + align:start position:0% + + + + align:start position:0% + +guys to deal with + + align:start position:0% +guys to deal with + + + align:start position:0% +guys to deal with +maybe there's a bigger one out here x of + + align:start position:0% +maybe there's a bigger one out here x of + + + align:start position:0% +maybe there's a bigger one out here x of +m minus one + + align:start position:0% +m minus one + + + align:start position:0% +m minus one +um + + align:start position:0% +um + + + align:start position:0% +um +to deal with and and + + align:start position:0% +to deal with and and + + + align:start position:0% +to deal with and and +that's how we define our our number is + + align:start position:0% +that's how we define our our number is + + + align:start position:0% +that's how we define our our number is +by + + align:start position:0% +by + + + align:start position:0% +by +the + + align:start position:0% +the + + + align:start position:0% +the +absolute value of x plus one uh plus + + align:start position:0% +absolute value of x plus one uh plus + + + align:start position:0% +absolute value of x plus one uh plus +these finite the absolute value of these + + align:start position:0% +these finite the absolute value of these + + + align:start position:0% +these finite the absolute value of these +finitely many and then that would be + + align:start position:0% +finitely many and then that would be + + + align:start position:0% +finitely many and then that would be +something that's bigger than or equal to + + align:start position:0% +something that's bigger than or equal to + + + align:start position:0% +something that's bigger than or equal to +every element in the sequence so how + + align:start position:0% +every element in the sequence so how + + + align:start position:0% +every element in the sequence so how +does + + align:start position:0% + + + + align:start position:0% + +that's the picture that goes with it how + + align:start position:0% +that's the picture that goes with it how + + + align:start position:0% +that's the picture that goes with it how +do we write + + align:start position:0% + + + + align:start position:0% + +how do we take that picture to proof + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% + + + + align:start position:0% + +suppose xn converges to x that's our + + align:start position:0% +suppose xn converges to x that's our + + + align:start position:0% +suppose xn converges to x that's our +assumption + + align:start position:0% + + + + align:start position:0% + +and there exists a natural number m + + align:start position:0% + + + + align:start position:0% + +such that + + align:start position:0% +such that + + + align:start position:0% +such that +all n bigger than or equal to capital m + + align:start position:0% + + + + align:start position:0% + +x sub n minus x is within distance one + + align:start position:0% +x sub n minus x is within distance one + + + align:start position:0% +x sub n minus x is within distance one +our x of n is within distance one to x + + align:start position:0% +our x of n is within distance one to x + + + align:start position:0% +our x of n is within distance one to x +then + + align:start position:0% +then + + + align:start position:0% +then +for all n bigger than or equal to + + align:start position:0% +for all n bigger than or equal to + + + align:start position:0% +for all n bigger than or equal to +capital m if we look at the absolute + + align:start position:0% +capital m if we look at the absolute + + + align:start position:0% +capital m if we look at the absolute +value of x sub n + + align:start position:0% + + + + align:start position:0% + +add and subtract x + + align:start position:0% +add and subtract x + + + align:start position:0% +add and subtract x +and now use the triangle inequality this + + align:start position:0% +and now use the triangle inequality this + + + align:start position:0% +and now use the triangle inequality this +is less than or equal to absolute value + + align:start position:0% +is less than or equal to absolute value + + + align:start position:0% +is less than or equal to absolute value +of x sub n minus x + + align:start position:0% +of x sub n minus x + + + align:start position:0% +of x sub n minus x +plus the absolute value of x equals one + + align:start position:0% +plus the absolute value of x equals one + + + align:start position:0% +plus the absolute value of x equals one +plus x + + align:start position:0% +plus x + + + align:start position:0% +plus x +okay so for all + + align:start position:0% +okay so for all + + + align:start position:0% +okay so for all +entries in the sequence past this point + + align:start position:0% +entries in the sequence past this point + + + align:start position:0% +entries in the sequence past this point +capital m + + align:start position:0% +capital m + + + align:start position:0% +capital m +they're bounded in absolute value by one + + align:start position:0% +they're bounded in absolute value by one + + + align:start position:0% +they're bounded in absolute value by one +plus x that's just a number okay + + align:start position:0% + + + + align:start position:0% + +so then + + align:start position:0% + + + + align:start position:0% + +we just have to take care of the + + align:start position:0% +we just have to take care of the + + + align:start position:0% +we just have to take care of the +one up to capital m minus one guys we + + align:start position:0% +one up to capital m minus one guys we + + + align:start position:0% +one up to capital m minus one guys we +just have to find a number bigger than + + align:start position:0% +just have to find a number bigger than + + + align:start position:0% +just have to find a number bigger than +those guys + + align:start position:0% +those guys + + + align:start position:0% +those guys +and this number + + align:start position:0% +and this number + + + align:start position:0% +and this number +and we'll have found a b so then let's + + align:start position:0% +and we'll have found a b so then let's + + + align:start position:0% +and we'll have found a b so then let's +take b to be + + align:start position:0% +take b to be + + + align:start position:0% +take b to be +x sub 1 + + align:start position:0% +x sub 1 + + + align:start position:0% +x sub 1 +plus x sub 2 plus + + align:start position:0% +plus x sub 2 plus + + + align:start position:0% +plus x sub 2 plus +x sub + + align:start position:0% +x sub + + + align:start position:0% +x sub +capital m minus 1 + + align:start position:0% +capital m minus 1 + + + align:start position:0% +capital m minus 1 +plus + + align:start position:0% + + + + align:start position:0% + +this + + align:start position:0% +this + + + align:start position:0% +this +okay + + align:start position:0% + + + + align:start position:0% + +then + + align:start position:0% +then + + + align:start position:0% +then +for all n a natural number + + align:start position:0% + + + + align:start position:0% + +the absolute value of x of n is less + + align:start position:0% +the absolute value of x of n is less + + + align:start position:0% +the absolute value of x of n is less +than or equal to b right because if n is + + align:start position:0% +than or equal to b right because if n is + + + align:start position:0% +than or equal to b right because if n is +less than + + align:start position:0% +less than + + + align:start position:0% +less than +capital m then its absolute value is + + align:start position:0% +capital m then its absolute value is + + + align:start position:0% +capital m then its absolute value is +bounded by one of these its absolute + + align:start position:0% +bounded by one of these its absolute + + + align:start position:0% +bounded by one of these its absolute +value is equal to one of these and + + align:start position:0% +value is equal to one of these and + + + align:start position:0% +value is equal to one of these and +therefore less than or equal to + + align:start position:0% +therefore less than or equal to + + + align:start position:0% +therefore less than or equal to +uh one of these plus some non-negative + + align:start position:0% +uh one of these plus some non-negative + + + align:start position:0% +uh one of these plus some non-negative +numbers + + align:start position:0% +numbers + + + align:start position:0% +numbers +and if n is bigger than or equal to + + align:start position:0% +and if n is bigger than or equal to + + + align:start position:0% +and if n is bigger than or equal to +capital m then we have this bound that + + align:start position:0% +capital m then we have this bound that + + + align:start position:0% +capital m then we have this bound that +we use + + align:start position:0% +we use + + + align:start position:0% +we use +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and this number is certainly less than + + align:start position:0% +and this number is certainly less than + + + align:start position:0% +and this number is certainly less than +or equal to capital b again because + + align:start position:0% +or equal to capital b again because + + + align:start position:0% +or equal to capital b again because +it's this number plus the sum of + + align:start position:0% +it's this number plus the sum of + + + align:start position:0% +it's this number plus the sum of +non-negative numbers + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +now in general there's no like easy + + align:start position:0% +now in general there's no like easy + + + align:start position:0% +now in general there's no like easy +like easily checkable + + align:start position:0% +like easily checkable + + + align:start position:0% +like easily checkable +criterion for a sequence to converge + + align:start position:0% +criterion for a sequence to converge + + + align:start position:0% +criterion for a sequence to converge +all we can do is verify the definition + + align:start position:0% + + + + align:start position:0% + +but there are some sequences which are + + align:start position:0% +but there are some sequences which are + + + align:start position:0% +but there are some sequences which are +you can easily check + + align:start position:0% +you can easily check + + + align:start position:0% +you can easily check +or or figure out if they converge just + + align:start position:0% +or or figure out if they converge just + + + align:start position:0% +or or figure out if they converge just +by telling if + + align:start position:0% +by telling if + + + align:start position:0% +by telling if +if they're bounded those are what are + + align:start position:0% +if they're bounded those are what are + + + align:start position:0% +if they're bounded those are what are +called monotone sequences + + align:start position:0% +called monotone sequences + + + align:start position:0% +called monotone sequences +so + + align:start position:0% + + + + align:start position:0% + +so this is in some sense the class of + + align:start position:0% +so this is in some sense the class of + + + align:start position:0% +so this is in some sense the class of +sequences that does kind of satisfy the + + align:start position:0% +sequences that does kind of satisfy the + + + align:start position:0% +sequences that does kind of satisfy the +converse of that theorem i stated a + + align:start position:0% +converse of that theorem i stated a + + + align:start position:0% +converse of that theorem i stated a +minute ago + + align:start position:0% +minute ago + + + align:start position:0% +minute ago +so sequence + + align:start position:0% +so sequence + + + align:start position:0% +so sequence +x of n is + + align:start position:0% + + + + align:start position:0% + +monotone increasing + + align:start position:0% + + + + align:start position:0% + +if + + align:start position:0% + + + + align:start position:0% + +for all natural numbers little n + + align:start position:0% +for all natural numbers little n + + + align:start position:0% +for all natural numbers little n +x of n is less than or equal to x of n + + align:start position:0% +x of n is less than or equal to x of n + + + align:start position:0% +x of n is less than or equal to x of n +plus one so this means that + + align:start position:0% + + + + align:start position:0% + +x of one is less than or equal to x sub + + align:start position:0% +x of one is less than or equal to x sub + + + align:start position:0% +x of one is less than or equal to x sub +two is less than or equal to x sub three + + align:start position:0% +two is less than or equal to x sub three + + + align:start position:0% +two is less than or equal to x sub three +and so on + + align:start position:0% + + + + align:start position:0% + +sequence is monotone decreasing + + align:start position:0% + + + + align:start position:0% + +if we have the other inequalities so + + align:start position:0% +if we have the other inequalities so + + + align:start position:0% +if we have the other inequalities so +things are getting + + align:start position:0% +things are getting + + + align:start position:0% +things are getting +smaller + + align:start position:0% +smaller + + + align:start position:0% +smaller +x sub n is bigger than or equal to x of + + align:start position:0% +x sub n is bigger than or equal to x of + + + align:start position:0% +x sub n is bigger than or equal to x of +n plus one + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +and if we have + + align:start position:0% +and if we have + + + align:start position:0% +and if we have +a sequence which is monotone increasing + + align:start position:0% + + + + align:start position:0% + +or monotone decreasing + + align:start position:0% + + + + align:start position:0% + +so it's one or the other + + align:start position:0% +so it's one or the other + + + align:start position:0% +so it's one or the other +you say xn is + + align:start position:0% + + + + align:start position:0% + +monotone or monotonic + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so + + align:start position:0% +so + + + align:start position:0% +so +you know it's simple enough to uh come + + align:start position:0% +you know it's simple enough to uh come + + + align:start position:0% +you know it's simple enough to uh come +up with examples of sequences which are + + align:start position:0% +up with examples of sequences which are + + + align:start position:0% +up with examples of sequences which are +monotone increasing monotone decreasing + + align:start position:0% +monotone increasing monotone decreasing + + + align:start position:0% +monotone increasing monotone decreasing +or neither so + + align:start position:0% + + + + align:start position:0% + +one over n so this is just + + align:start position:0% +one over n so this is just + + + align:start position:0% +one over n so this is just +one one-half + + align:start position:0% +one one-half + + + align:start position:0% +one one-half +third + + align:start position:0% +third + + + align:start position:0% +third +fourth + + align:start position:0% +fourth + + + align:start position:0% +fourth +this is + + align:start position:0% + + + + align:start position:0% + +monotone decreasing + + align:start position:0% +monotone decreasing + + + align:start position:0% +monotone decreasing +and if i + + align:start position:0% +and if i + + + align:start position:0% +and if i +take minus + + align:start position:0% +take minus + + + align:start position:0% +take minus +uh the sequence then i get that reverses + + align:start position:0% +uh the sequence then i get that reverses + + + align:start position:0% +uh the sequence then i get that reverses +basically all of the inequalities and i + + align:start position:0% +basically all of the inequalities and i + + + align:start position:0% +basically all of the inequalities and i +get a monotone increasing one so then + + align:start position:0% +get a monotone increasing one so then + + + align:start position:0% +get a monotone increasing one so then +this is minus one minus a half + + align:start position:0% +this is minus one minus a half + + + align:start position:0% +this is minus one minus a half +minus the third minus the fourth + + align:start position:0% + + + + align:start position:0% + +monotone increasing and then something + + align:start position:0% +monotone increasing and then something + + + align:start position:0% +monotone increasing and then something +that's not is we've already + + align:start position:0% +that's not is we've already + + + align:start position:0% +that's not is we've already +come across that minus one to the n + + align:start position:0% + + + + align:start position:0% + +and so on + + align:start position:0% + + + + align:start position:0% + +okay and so + + align:start position:0% +okay and so + + + align:start position:0% +okay and so +the theorem about monotone sequences is + + align:start position:0% +the theorem about monotone sequences is + + + align:start position:0% +the theorem about monotone sequences is +um + + align:start position:0% +um + + + align:start position:0% +um +that there's a simpler criterion than + + align:start position:0% +that there's a simpler criterion than + + + align:start position:0% +that there's a simpler criterion than +the definition for + + align:start position:0% +the definition for + + + align:start position:0% +the definition for +determining when they're convergent or + + align:start position:0% +determining when they're convergent or + + + align:start position:0% +determining when they're convergent or +if you like + + align:start position:0% +if you like + + + align:start position:0% +if you like +they satisfy the converse of this + + align:start position:0% +they satisfy the converse of this + + + align:start position:0% +they satisfy the converse of this +theorem up here + + align:start position:0% +theorem up here + + + align:start position:0% +theorem up here +so + + align:start position:0% + + + + align:start position:0% + +monotonic sequence + + align:start position:0% + + + + align:start position:0% + +is convergent + + align:start position:0% + + + + align:start position:0% + +if and only if + + align:start position:0% + + + + align:start position:0% + +it is bounded okay so we proved a minute + + align:start position:0% +it is bounded okay so we proved a minute + + + align:start position:0% +it is bounded okay so we proved a minute +ago that convergent sequences are + + align:start position:0% +ago that convergent sequences are + + + align:start position:0% +ago that convergent sequences are +bounded so for monotonic sequences + + align:start position:0% +bounded so for monotonic sequences + + + align:start position:0% +bounded so for monotonic sequences +converse holds + + align:start position:0% +converse holds + + + align:start position:0% +converse holds +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so let's do the proof of this i'm gonna + + align:start position:0% +so let's do the proof of this i'm gonna + + + align:start position:0% +so let's do the proof of this i'm gonna +do the proof for monotone increasing + + align:start position:0% +do the proof for monotone increasing + + + align:start position:0% +do the proof for monotone increasing +uh + + align:start position:0% +uh + + + align:start position:0% +uh +sequences and as an exercise i'll leave + + align:start position:0% +sequences and as an exercise i'll leave + + + align:start position:0% +sequences and as an exercise i'll leave +it to you to do the proof for monotone + + align:start position:0% +it to you to do the proof for monotone + + + align:start position:0% +it to you to do the proof for monotone +decreasing sequences + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% + + + + align:start position:0% + +suppose x of n is + + align:start position:0% + + + + align:start position:0% + +a monotone + + align:start position:0% +a monotone + + + align:start position:0% +a monotone +increasing sequence + + align:start position:0% + + + + align:start position:0% + +so there's two + + align:start position:0% +so there's two + + + align:start position:0% +so there's two +directions to prove convergence + + align:start position:0% +directions to prove convergence + + + align:start position:0% +directions to prove convergence +if and only if bounded + + align:start position:0% +if and only if bounded + + + align:start position:0% +if and only if bounded +so we have one direction + + align:start position:0% +so we have one direction + + + align:start position:0% +so we have one direction +meaning + + align:start position:0% +meaning + + + align:start position:0% +meaning +convergence implies bounded this is just + + align:start position:0% +convergence implies bounded this is just + + + align:start position:0% +convergence implies bounded this is just +the previous theorem + + align:start position:0% + + + + align:start position:0% + +where we proved that every convergent + + align:start position:0% +where we proved that every convergent + + + align:start position:0% +where we proved that every convergent +sequence is bounded not just monotonic + + align:start position:0% +sequence is bounded not just monotonic + + + align:start position:0% +sequence is bounded not just monotonic +sequences + + align:start position:0% +sequences + + + align:start position:0% +sequences +so + + align:start position:0% +so + + + align:start position:0% +so +the meat is in proving the converse + + align:start position:0% +the meat is in proving the converse + + + align:start position:0% +the meat is in proving the converse +direction and in fact we'll be able to + + align:start position:0% +direction and in fact we'll be able to + + + align:start position:0% +direction and in fact we'll be able to +pick out uh what the limit is of this + + align:start position:0% +pick out uh what the limit is of this + + + align:start position:0% +pick out uh what the limit is of this +sequence + + align:start position:0% +sequence + + + align:start position:0% +sequence +so + + align:start position:0% + + + + align:start position:0% + +suppose x of n is + + align:start position:0% + + + + align:start position:0% + +bounded + + align:start position:0% +bounded + + + align:start position:0% +bounded +okay + + align:start position:0% + + + + align:start position:0% + +then if i look at the set of entries + + align:start position:0% +then if i look at the set of entries + + + align:start position:0% +then if i look at the set of entries +okay so not the sequence but if i look + + align:start position:0% +okay so not the sequence but if i look + + + align:start position:0% +okay so not the sequence but if i look +at + + align:start position:0% +at + + + align:start position:0% +at +the set + + align:start position:0% +the set + + + align:start position:0% +the set +of values + + align:start position:0% +of values + + + align:start position:0% +of values +that this uh sequence takes so x sub n + + align:start position:0% +that this uh sequence takes so x sub n + + + align:start position:0% +that this uh sequence takes so x sub n +and it's a natural number this is now a + + align:start position:0% +and it's a natural number this is now a + + + align:start position:0% +and it's a natural number this is now a +set + + align:start position:0% +set + + + align:start position:0% +set +subset of the real numbers + + align:start position:0% + + + + align:start position:0% + +this is a bounded set + + align:start position:0% + + + + align:start position:0% + +meaning it's bounded above + + align:start position:0% + + + + align:start position:0% + +and below because there exists some + + align:start position:0% +and below because there exists some + + + align:start position:0% +and below because there exists some +capital b so that + + align:start position:0% +capital b so that + + + align:start position:0% +capital b so that +x sub n is + + align:start position:0% +x sub n is + + + align:start position:0% +x sub n is +um + + align:start position:0% +um + + + align:start position:0% +um +an absolute value less than or equal to + + align:start position:0% +an absolute value less than or equal to + + + align:start position:0% +an absolute value less than or equal to +capital b for all n so that means x sub + + align:start position:0% +capital b for all n so that means x sub + + + align:start position:0% +capital b for all n so that means x sub +n is between b and minus b + + align:start position:0% +n is between b and minus b + + + align:start position:0% +n is between b and minus b +okay + + align:start position:0% + + + + align:start position:0% + +all right so + + align:start position:0% +all right so + + + align:start position:0% +all right so +what's the picture again that goes with + + align:start position:0% +what's the picture again that goes with + + + align:start position:0% +what's the picture again that goes with +this so we have these x sub n's + + align:start position:0% +this so we have these x sub n's + + + align:start position:0% +this so we have these x sub n's +one x sub two x three we know that they + + align:start position:0% +one x sub two x three we know that they + + + align:start position:0% +one x sub two x three we know that they +cannot go past a certain + + align:start position:0% +cannot go past a certain + + + align:start position:0% +cannot go past a certain +b + + align:start position:0% +b + + + align:start position:0% +b +uh and they're + + align:start position:0% +uh and they're + + + align:start position:0% +uh and they're +steadily increasing but they can't + + align:start position:0% +steadily increasing but they can't + + + align:start position:0% +steadily increasing but they can't +keep + + align:start position:0% +keep + + + align:start position:0% +keep +strictly + + align:start position:0% +strictly + + + align:start position:0% +strictly +they can't increase without bound so + + align:start position:0% + + + + align:start position:0% + +um + + align:start position:0% +um + + + align:start position:0% +um +not only that they're bounded by + + align:start position:0% +not only that they're bounded by + + + align:start position:0% +not only that they're bounded by +uh some + + align:start position:0% +uh some + + + align:start position:0% +uh some +number + + align:start position:0% +number + + + align:start position:0% +number +x which i'll define to be the supremum + + align:start position:0% +x which i'll define to be the supremum + + + align:start position:0% +x which i'll define to be the supremum +of this set + + align:start position:0% +of this set + + + align:start position:0% +of this set +and these guys are just getting in in + + align:start position:0% +and these guys are just getting in in + + + align:start position:0% +and these guys are just getting in in +essence so this is a picture i mean + + align:start position:0% +essence so this is a picture i mean + + + align:start position:0% +essence so this is a picture i mean +me trying to explain to you what's going + + align:start position:0% +me trying to explain to you what's going + + + align:start position:0% +me trying to explain to you what's going +on + + align:start position:0% +on + + + align:start position:0% +on +if x is the + + align:start position:0% +if x is the + + + align:start position:0% +if x is the +soup of this + + align:start position:0% +soup of this + + + align:start position:0% +soup of this +set of entries + + align:start position:0% + + + + align:start position:0% + +then what do i know about x sub n + + align:start position:0% +then what do i know about x sub n + + + align:start position:0% +then what do i know about x sub n +i mean x + + align:start position:0% +i mean x + + + align:start position:0% +i mean x +is that if i go a little bit to the left + + align:start position:0% +is that if i go a little bit to the left + + + align:start position:0% +is that if i go a little bit to the left +of x so let me draw this again + + align:start position:0% +of x so let me draw this again + + + align:start position:0% +of x so let me draw this again +so okay so let me uh let me back up a + + align:start position:0% +so okay so let me uh let me back up a + + + align:start position:0% +so okay so let me uh let me back up a +minute here + + align:start position:0% + + + + align:start position:0% + +so since the set is bounded in r + + align:start position:0% +so since the set is bounded in r + + + align:start position:0% +so since the set is bounded in r +it has a supremum in r + + align:start position:0% + + + + align:start position:0% + +and what i claim is that this supremum + + align:start position:0% +and what i claim is that this supremum + + + align:start position:0% +and what i claim is that this supremum +is in fact the limit of this sequence + + align:start position:0% +is in fact the limit of this sequence + + + align:start position:0% +is in fact the limit of this sequence +okay this is a supremum of a set + + align:start position:0% +okay this is a supremum of a set + + + align:start position:0% +okay this is a supremum of a set +i'm saying it's the limit of the + + align:start position:0% +i'm saying it's the limit of the + + + align:start position:0% +i'm saying it's the limit of the +sequence so what's the what's the + + align:start position:0% +sequence so what's the what's the + + + align:start position:0% +sequence so what's the what's the +thinking here + + align:start position:0% +thinking here + + + align:start position:0% +thinking here +um so x is the supremum of all the + + align:start position:0% +um so x is the supremum of all the + + + align:start position:0% +um so x is the supremum of all the +entries in x sub n so nothing's ever + + align:start position:0% +entries in x sub n so nothing's ever + + + align:start position:0% +entries in x sub n so nothing's ever +going to be bigger than + + align:start position:0% +going to be bigger than + + + align:start position:0% +going to be bigger than +uh + + align:start position:0% +uh + + + align:start position:0% +uh +some tolerance x plus epsilon so we just + + align:start position:0% +some tolerance x plus epsilon so we just + + + align:start position:0% +some tolerance x plus epsilon so we just +need to worry about what's to the left + + align:start position:0% +need to worry about what's to the left + + + align:start position:0% +need to worry about what's to the left +of it + + align:start position:0% +of it + + + align:start position:0% +of it +and we need to find a capital number m + + align:start position:0% +and we need to find a capital number m + + + align:start position:0% +and we need to find a capital number m +so that all the x of n's are in this + + align:start position:0% +so that all the x of n's are in this + + + align:start position:0% +so that all the x of n's are in this +this + + align:start position:0% +this + + + align:start position:0% +this +interval here + + align:start position:0% +interval here + + + align:start position:0% +interval here +okay + + align:start position:0% + + + + align:start position:0% + +because we're trying to show that + + align:start position:0% + + + + align:start position:0% + +we're trying to show that the extra + + align:start position:0% +we're trying to show that the extra + + + align:start position:0% +we're trying to show that the extra +bends converge to x the supremum of this + + align:start position:0% +bends converge to x the supremum of this + + + align:start position:0% +bends converge to x the supremum of this +guy so let's walk through this + + align:start position:0% + + + + align:start position:0% + +by this picture so x is the supremum + + align:start position:0% +by this picture so x is the supremum + + + align:start position:0% +by this picture so x is the supremum +nothing's bigger + + align:start position:0% +nothing's bigger + + + align:start position:0% +nothing's bigger +than x so all of the x of n's are to the + + align:start position:0% +than x so all of the x of n's are to the + + + align:start position:0% +than x so all of the x of n's are to the +left of x plus epsilon so now we just + + align:start position:0% +left of x plus epsilon so now we just + + + align:start position:0% +left of x plus epsilon so now we just +need to worry about x minus epsilon + + align:start position:0% +need to worry about x minus epsilon + + + align:start position:0% +need to worry about x minus epsilon +now since x is the supremum of this set + + align:start position:0% +now since x is the supremum of this set + + + align:start position:0% +now since x is the supremum of this set +x minus epsilon can't be an upper bound + + align:start position:0% +x minus epsilon can't be an upper bound + + + align:start position:0% +x minus epsilon can't be an upper bound +for the set of entries of x sub n so + + align:start position:0% +for the set of entries of x sub n so + + + align:start position:0% +for the set of entries of x sub n so +that means there has to exist some + + align:start position:0% +that means there has to exist some + + + align:start position:0% +that means there has to exist some +x sub m + + align:start position:0% +x sub m + + + align:start position:0% +x sub m +so that it's bigger than x minus epsilon + + align:start position:0% +so that it's bigger than x minus epsilon + + + align:start position:0% +so that it's bigger than x minus epsilon +but now this is where we use the fact + + align:start position:0% +but now this is where we use the fact + + + align:start position:0% +but now this is where we use the fact +that this is a monotone increasing + + align:start position:0% +that this is a monotone increasing + + + align:start position:0% +that this is a monotone increasing +sequence + + align:start position:0% +sequence + + + align:start position:0% +sequence +because then if n is bigger than or + + align:start position:0% +because then if n is bigger than or + + + align:start position:0% +because then if n is bigger than or +equal to capital m then x sub n is + + align:start position:0% +equal to capital m then x sub n is + + + align:start position:0% +equal to capital m then x sub n is +strictly to the right of + + align:start position:0% +strictly to the right of + + + align:start position:0% +strictly to the right of +x sub m or it's equal to x sub n + + align:start position:0% + + + + align:start position:0% + +and still less than or equal to x + + align:start position:0% +and still less than or equal to x + + + align:start position:0% +and still less than or equal to x +because x is the supremum of all the + + align:start position:0% +because x is the supremum of all the + + + align:start position:0% +because x is the supremum of all the +entries + + align:start position:0% +entries + + + align:start position:0% +entries +so then for n bigger than or equal to + + align:start position:0% +so then for n bigger than or equal to + + + align:start position:0% +so then for n bigger than or equal to +capital m they all have to lie in this + + align:start position:0% +capital m they all have to lie in this + + + align:start position:0% +capital m they all have to lie in this +interval and that's why the + + align:start position:0% +interval and that's why the + + + align:start position:0% +interval and that's why the +sequence converges to the supremum of + + align:start position:0% +sequence converges to the supremum of + + + align:start position:0% +sequence converges to the supremum of +this set so we're using + + align:start position:0% +this set so we're using + + + align:start position:0% +this set so we're using +um in a crucial way this the fact that + + align:start position:0% +um in a crucial way this the fact that + + + align:start position:0% +um in a crucial way this the fact that +this uh sequence is monotonic increasing + + align:start position:0% + + + + align:start position:0% + +so to prove this claim let epsilon be + + align:start position:0% +so to prove this claim let epsilon be + + + align:start position:0% +so to prove this claim let epsilon be +positive + + align:start position:0% +positive + + + align:start position:0% +positive +then + + align:start position:0% + + + + align:start position:0% + +since x minus epsilon is not + + align:start position:0% + + + + align:start position:0% + +an upper bound for + + align:start position:0% +an upper bound for + + + align:start position:0% +an upper bound for +this set x sub n + + align:start position:0% + + + + align:start position:0% + +there exists an m naught + + align:start position:0% +there exists an m naught + + + align:start position:0% +there exists an m naught +natural number so that + + align:start position:0% +natural number so that + + + align:start position:0% +natural number so that +x of n minus epsilon is less than x sub + + align:start position:0% +x of n minus epsilon is less than x sub + + + align:start position:0% +x of n minus epsilon is less than x sub +m naught + + align:start position:0% +m naught + + + align:start position:0% +m naught +is less than or equal to x + + align:start position:0% + + + + align:start position:0% + +and we'll choose + + align:start position:0% + + + + align:start position:0% + +m to be this m naught + + align:start position:0% + + + + align:start position:0% + +then + + align:start position:0% +then + + + align:start position:0% +then +for all n bigger than or equal to m we + + align:start position:0% +for all n bigger than or equal to m we + + + align:start position:0% +for all n bigger than or equal to m we +have x sub n + + align:start position:0% +have x sub n + + + align:start position:0% +have x sub n +minus epsilon which is less than x sub + + align:start position:0% +minus epsilon which is less than x sub + + + align:start position:0% +minus epsilon which is less than x sub +m naught and because n is bigger than or + + align:start position:0% +m naught and because n is bigger than or + + + align:start position:0% +m naught and because n is bigger than or +equal to capital m and this is a + + align:start position:0% +equal to capital m and this is a + + + align:start position:0% +equal to capital m and this is a +monotone increasing sequence x sub m + + align:start position:0% +monotone increasing sequence x sub m + + + align:start position:0% +monotone increasing sequence x sub m +naught is less than or equal to x sub n + + align:start position:0% +naught is less than or equal to x sub n + + + align:start position:0% +naught is less than or equal to x sub n +and because x is a supremum of + + align:start position:0% +and because x is a supremum of + + + align:start position:0% +and because x is a supremum of +of um + + align:start position:0% +of um + + + align:start position:0% +of um +the set of all entries of this sequence + + align:start position:0% +the set of all entries of this sequence + + + align:start position:0% +the set of all entries of this sequence +this is less than or equal to x + + align:start position:0% +this is less than or equal to x + + + align:start position:0% +this is less than or equal to x +which is less than + + align:start position:0% +which is less than + + + align:start position:0% +which is less than +x plus epsilon + + align:start position:0% +x plus epsilon + + + align:start position:0% +x plus epsilon +or to summarize so this should not be x + + align:start position:0% +or to summarize so this should not be x + + + align:start position:0% +or to summarize so this should not be x +sub n that should be x minus epsilon + + align:start position:0% +sub n that should be x minus epsilon + + + align:start position:0% +sub n that should be x minus epsilon +or + + align:start position:0% +or + + + align:start position:0% +or +x minus epsilon is less than x of n is + + align:start position:0% +x minus epsilon is less than x of n is + + + align:start position:0% +x minus epsilon is less than x of n is +less than + + align:start position:0% +less than + + + align:start position:0% +less than +x plus epsilon and that's the same as + + align:start position:0% +x plus epsilon and that's the same as + + + align:start position:0% +x plus epsilon and that's the same as +showing the absolute value of x of n + + align:start position:0% +showing the absolute value of x of n + + + align:start position:0% +showing the absolute value of x of n +minus x is less than epsilon + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +now what's the change for + + align:start position:0% +now what's the change for + + + align:start position:0% +now what's the change for +monotone decreasing is that + + align:start position:0% +monotone decreasing is that + + + align:start position:0% +monotone decreasing is that +we'll be able to identify + + align:start position:0% +we'll be able to identify + + + align:start position:0% +we'll be able to identify +the + + align:start position:0% +the + + + align:start position:0% +the +limit of the sequence as being the imph + + align:start position:0% +limit of the sequence as being the imph + + + align:start position:0% +limit of the sequence as being the imph +the enthemum of this set + + align:start position:0% +the enthemum of this set + + + align:start position:0% +the enthemum of this set +all right but i'll leave that to you as + + align:start position:0% +all right but i'll leave that to you as + + + align:start position:0% +all right but i'll leave that to you as +an exercise + + align:start position:0% + + + + align:start position:0% + +so let's use this real quick to uh prove + + align:start position:0% +so let's use this real quick to uh prove + + + align:start position:0% +so let's use this real quick to uh prove +the limit of a + + align:start position:0% +the limit of a + + + align:start position:0% +the limit of a +little bit more interesting sequence + + align:start position:0% +little bit more interesting sequence + + + align:start position:0% +little bit more interesting sequence +than + + align:start position:0% +than + + + align:start position:0% +than +you know one over + + align:start position:0% +you know one over + + + align:start position:0% +you know one over +this one which + + align:start position:0% + + + + align:start position:0% + +it's reasonably interesting i guess but + + align:start position:0% + + + + align:start position:0% + +you know typically in math we just don't + + align:start position:0% +you know typically in math we just don't + + + align:start position:0% +you know typically in math we just don't +prove + + align:start position:0% +prove + + + align:start position:0% +prove +theorems for the sake of proving + + align:start position:0% +theorems for the sake of proving + + + align:start position:0% +theorems for the sake of proving +theorems + + align:start position:0% +theorems + + + align:start position:0% +theorems +typically there's some concrete + + align:start position:0% +typically there's some concrete + + + align:start position:0% +typically there's some concrete +um + + align:start position:0% +um + + + align:start position:0% +um +reason we do things + + align:start position:0% +reason we do things + + + align:start position:0% +reason we do things +there's some concrete sequence we're + + align:start position:0% +there's some concrete sequence we're + + + align:start position:0% +there's some concrete sequence we're +trying to prove converges or + + align:start position:0% +trying to prove converges or + + + align:start position:0% +trying to prove converges or +has a certain property + + align:start position:0% +has a certain property + + + align:start position:0% +has a certain property +or doesn't have a certain property + + align:start position:0% +or doesn't have a certain property + + + align:start position:0% +or doesn't have a certain property +and + + align:start position:0% + + + + align:start position:0% + +so kind of the basic one is + + align:start position:0% +so kind of the basic one is + + + align:start position:0% +so kind of the basic one is +if you like a geometric sequence so + + align:start position:0% + + + + align:start position:0% + +if c + + align:start position:0% + + + + align:start position:0% + +is a positive number between zero and + + align:start position:0% +is a positive number between zero and + + + align:start position:0% +is a positive number between zero and +one + + align:start position:0% + + + + align:start position:0% + +then + + align:start position:0% +then + + + align:start position:0% +then +we'll prove that + + align:start position:0% + + + + align:start position:0% + +this sequence c to the n is convergent + + align:start position:0% +this sequence c to the n is convergent + + + align:start position:0% +this sequence c to the n is convergent +and it converges to zero + + align:start position:0% + + + + align:start position:0% + +and we'll prove as c if c is bigger than + + align:start position:0% +and we'll prove as c if c is bigger than + + + align:start position:0% +and we'll prove as c if c is bigger than +one + + align:start position:0% + + + + align:start position:0% + +then the sequence c to the n + + align:start position:0% + + + + align:start position:0% + +is unbounded in particular it can't + + align:start position:0% +is unbounded in particular it can't + + + align:start position:0% +is unbounded in particular it can't +converge + + align:start position:0% +converge + + + align:start position:0% +converge +okay + + align:start position:0% + + + + align:start position:0% + +so let's do um + + align:start position:0% +so let's do um + + + align:start position:0% +so let's do um +let's go in reverse order let's prove + + align:start position:0% +let's go in reverse order let's prove + + + align:start position:0% +let's go in reverse order let's prove +that uh + + align:start position:0% +that uh + + + align:start position:0% +that uh +if c is bigger than one then this thing + + align:start position:0% +if c is bigger than one then this thing + + + align:start position:0% +if c is bigger than one then this thing +is unbounded + + align:start position:0% +is unbounded + + + align:start position:0% +is unbounded +it doesn't require one but it's shorter + + align:start position:0% +it doesn't require one but it's shorter + + + align:start position:0% +it doesn't require one but it's shorter +than one and we can go ahead and do it + + align:start position:0% +than one and we can go ahead and do it + + + align:start position:0% +than one and we can go ahead and do it +um and we'll use this fact that we + + align:start position:0% +um and we'll use this fact that we + + + align:start position:0% +um and we'll use this fact that we +proved um i think in the first lecture + + align:start position:0% +proved um i think in the first lecture + + + align:start position:0% +proved um i think in the first lecture +uh or first or second lecture using + + align:start position:0% +uh or first or second lecture using + + + align:start position:0% +uh or first or second lecture using +induction + + align:start position:0% +induction + + + align:start position:0% +induction +so + + align:start position:0% +so + + + align:start position:0% +so +what does it mean to show something is + + align:start position:0% +what does it mean to show something is + + + align:start position:0% +what does it mean to show something is +unbounded again we get to use our + + align:start position:0% +unbounded again we get to use our + + + align:start position:0% +unbounded again we get to use our +negation skills + + align:start position:0% +negation skills + + + align:start position:0% +negation skills +it means that so what do we want to show + + align:start position:0% + + + + align:start position:0% + +for all + + align:start position:0% +for all + + + align:start position:0% +for all +uh b + + align:start position:0% +uh b + + + align:start position:0% +uh b +bigger than or equal to zero + + align:start position:0% +bigger than or equal to zero + + + align:start position:0% +bigger than or equal to zero +there exist an n + + align:start position:0% +there exist an n + + + align:start position:0% +there exist an n +natural number + + align:start position:0% +natural number + + + align:start position:0% +natural number +so that + + align:start position:0% +so that + + + align:start position:0% +so that +c to the n is + + align:start position:0% +c to the n is + + + align:start position:0% +c to the n is +bigger than b + + align:start position:0% +bigger than b + + + align:start position:0% +bigger than b +okay + + align:start position:0% + + + + align:start position:0% + +okay now how are we going to find this + + align:start position:0% +okay now how are we going to find this + + + align:start position:0% +okay now how are we going to find this +in + + align:start position:0% +in + + + align:start position:0% +in +this seems like a complicated thing + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +let's replace it by something simpler + + align:start position:0% +let's replace it by something simpler + + + align:start position:0% +let's replace it by something simpler +again this is analysis which means + + align:start position:0% + + + + align:start position:0% + +we get to use our wits and try to + + align:start position:0% +we get to use our wits and try to + + + align:start position:0% +we get to use our wits and try to +replace complicated things by simpler + + align:start position:0% +replace complicated things by simpler + + + align:start position:0% +replace complicated things by simpler +things and work with the simpler things + + align:start position:0% + + + + align:start position:0% + +so let me do a little bit of again this + + align:start position:0% +so let me do a little bit of again this + + + align:start position:0% +so let me do a little bit of again this +is off to the side kind of how would one + + align:start position:0% +is off to the side kind of how would one + + + align:start position:0% +is off to the side kind of how would one +thing through this + + align:start position:0% +thing through this + + + align:start position:0% +thing through this +if you look at c to the n remember we + + align:start position:0% +if you look at c to the n remember we + + + align:start position:0% +if you look at c to the n remember we +have this inequality from + + align:start position:0% +have this inequality from + + + align:start position:0% +have this inequality from +uh infinite time ago that + + align:start position:0% +uh infinite time ago that + + + align:start position:0% +uh infinite time ago that +one that as long as x is bigger than or + + align:start position:0% +one that as long as x is bigger than or + + + align:start position:0% +one that as long as x is bigger than or +equal to + + align:start position:0% + + + + align:start position:0% + +minus 1 then i get 1 plus x to the n + + align:start position:0% +minus 1 then i get 1 plus x to the n + + + align:start position:0% +minus 1 then i get 1 plus x to the n +is bigger than 1 plus n times x + + align:start position:0% +is bigger than 1 plus n times x + + + align:start position:0% +is bigger than 1 plus n times x +okay for all natural numbers n + + align:start position:0% + + + + align:start position:0% + +okay so that means c to the n + + align:start position:0% + + + + align:start position:0% + +which is equal to 1 plus c minus 1 + + align:start position:0% +which is equal to 1 plus c minus 1 + + + align:start position:0% +which is equal to 1 plus c minus 1 +to the n so this is my x is bigger than + + align:start position:0% +to the n so this is my x is bigger than + + + align:start position:0% +to the n so this is my x is bigger than +or equal to + + align:start position:0% +or equal to + + + align:start position:0% +or equal to +1 plus n times c minus 1 + + align:start position:0% +1 plus n times c minus 1 + + + align:start position:0% +1 plus n times c minus 1 +which is bigger than or equal to n times + + align:start position:0% + + + + align:start position:0% + +c minus 1. + + align:start position:0% +c minus 1. + + + align:start position:0% +c minus 1. +you see so if i want to make if i want + + align:start position:0% +you see so if i want to make if i want + + + align:start position:0% +you see so if i want to make if i want +to make this big it suffices to make + + align:start position:0% +to make this big it suffices to make + + + align:start position:0% +to make this big it suffices to make +this big + + align:start position:0% +this big + + + align:start position:0% +this big +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so that's how that's what i'll do + + align:start position:0% +so that's how that's what i'll do + + + align:start position:0% +so that's how that's what i'll do +so + + align:start position:0% +so + + + align:start position:0% +so +um + + align:start position:0% + + + + align:start position:0% + +let n be a natural number + + align:start position:0% + + + + align:start position:0% + +such that + + align:start position:0% +such that + + + align:start position:0% +such that +n is bigger than + + align:start position:0% +n is bigger than + + + align:start position:0% +n is bigger than +b over c minus one + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +then now this we did off to the side + + align:start position:0% +then now this we did off to the side + + + align:start position:0% +then now this we did off to the side +we'll just put in the proof now + + align:start position:0% + + + + align:start position:0% + +and c to the n equals 1 plus + + align:start position:0% +and c to the n equals 1 plus + + + align:start position:0% +and c to the n equals 1 plus +1 minus c + + align:start position:0% +1 minus c + + + align:start position:0% +1 minus c +to the n + + align:start position:0% +to the n + + + align:start position:0% +to the n +is bigger than or equal to 1 plus n + + align:start position:0% +is bigger than or equal to 1 plus n + + + align:start position:0% +is bigger than or equal to 1 plus n +times c minus 1 which is bigger than or + + align:start position:0% +times c minus 1 which is bigger than or + + + align:start position:0% +times c minus 1 which is bigger than or +equal to n + + align:start position:0% +equal to n + + + align:start position:0% +equal to n +times c minus 1 which is + + align:start position:0% +times c minus 1 which is + + + align:start position:0% +times c minus 1 which is +bigger than b + + align:start position:0% +bigger than b + + + align:start position:0% +bigger than b +over c minus 1 times c minus 1 equals b + + align:start position:0% +over c minus 1 times c minus 1 equals b + + + align:start position:0% +over c minus 1 times c minus 1 equals b +okay + + align:start position:0% + + + + align:start position:0% + +okay so now let's prove uh + + align:start position:0% +okay so now let's prove uh + + + align:start position:0% +okay so now let's prove uh +the first claim that if c is between + + align:start position:0% +the first claim that if c is between + + + align:start position:0% +the first claim that if c is between +zero and one then the limit as n goes to + + align:start position:0% +zero and one then the limit as n goes to + + + align:start position:0% +zero and one then the limit as n goes to +infinity of c to the n equals zero + + align:start position:0% +infinity of c to the n equals zero + + + align:start position:0% +infinity of c to the n equals zero +so first i want to prove uh the + + align:start position:0% +so first i want to prove uh the + + + align:start position:0% +so first i want to prove uh the +following claim that we in fact have a + + align:start position:0% +following claim that we in fact have a + + + align:start position:0% +following claim that we in fact have a +decreasing sequence + + align:start position:0% +decreasing sequence + + + align:start position:0% +decreasing sequence +uh which is bounded below by + + align:start position:0% +uh which is bounded below by + + + align:start position:0% +uh which is bounded below by +um + + align:start position:0% +um + + + align:start position:0% +um +zero so + + align:start position:0% + + + + align:start position:0% + +claim + + align:start position:0% + + + + align:start position:0% + +for all n 0 is less than c to the n is + + align:start position:0% +for all n 0 is less than c to the n is + + + align:start position:0% +for all n 0 is less than c to the n is +less than + + align:start position:0% +less than + + + align:start position:0% +less than +i should say c to the n plus 1 + + align:start position:0% +i should say c to the n plus 1 + + + align:start position:0% +i should say c to the n plus 1 +is less than c to the n + + align:start position:0% +is less than c to the n + + + align:start position:0% +is less than c to the n +okay + + align:start position:0% + + + + align:start position:0% + +so the proof of this claim is a very + + align:start position:0% +so the proof of this claim is a very + + + align:start position:0% +so the proof of this claim is a very +simple induction argument so we'll do + + align:start position:0% +simple induction argument so we'll do + + + align:start position:0% +simple induction argument so we'll do +this by induction so we have the base + + align:start position:0% +this by induction so we have the base + + + align:start position:0% +this by induction so we have the base +case + + align:start position:0% + + + + align:start position:0% + +n equals one + + align:start position:0% +n equals one + + + align:start position:0% +n equals one +so + + align:start position:0% +so + + + align:start position:0% +so +we are assuming that + + align:start position:0% + + + + align:start position:0% + +c is between zero and one + + align:start position:0% +c is between zero and one + + + align:start position:0% +c is between zero and one +and if i multiply through by c + + align:start position:0% +and if i multiply through by c + + + align:start position:0% +and if i multiply through by c +i conclude that zero is less than c + + align:start position:0% +i conclude that zero is less than c + + + align:start position:0% +i conclude that zero is less than c +squared is less than c + + align:start position:0% +squared is less than c + + + align:start position:0% +squared is less than c +and that's the n equals one case + + align:start position:0% +and that's the n equals one case + + + align:start position:0% +and that's the n equals one case +and the inductive step + + align:start position:0% + + + + align:start position:0% + +i mean is essentially the same proof + + align:start position:0% + + + + align:start position:0% + +suppose + + align:start position:0% + + + + align:start position:0% + +0 is less than c + + align:start position:0% +0 is less than c + + + align:start position:0% +0 is less than c +to the n plus 1 is less than c to the m + + align:start position:0% + + + + align:start position:0% + +then multiplying through by c + + align:start position:0% +then multiplying through by c + + + align:start position:0% +then multiplying through by c +we get that + + align:start position:0% +we get that + + + align:start position:0% +we get that +0 is less than c to the m + + align:start position:0% +0 is less than c to the m + + + align:start position:0% +0 is less than c to the m +plus 2 is less than + + align:start position:0% +plus 2 is less than + + + align:start position:0% +plus 2 is less than +c to the n plus one which is n equals n + + align:start position:0% +c to the n plus one which is n equals n + + + align:start position:0% +c to the n plus one which is n equals n +plus one + + align:start position:0% +plus one + + + align:start position:0% +plus one +okay here we're using + + align:start position:0% +okay here we're using + + + align:start position:0% +okay here we're using +uh this fact here okay that c is + + align:start position:0% +uh this fact here okay that c is + + + align:start position:0% +uh this fact here okay that c is +positive so it doesn't flip the + + align:start position:0% +positive so it doesn't flip the + + + align:start position:0% +positive so it doesn't flip the +inequalities + + align:start position:0% +inequalities + + + align:start position:0% +inequalities +so i can multiply through and preserve + + align:start position:0% +so i can multiply through and preserve + + + align:start position:0% +so i can multiply through and preserve +the inequalities + + align:start position:0% + + + + align:start position:0% + +okay so + + align:start position:0% +okay so + + + align:start position:0% +okay so +this shows that + + align:start position:0% + + + + align:start position:0% + +that this sequence is + + align:start position:0% + + + + align:start position:0% + +monotone + + align:start position:0% +monotone + + + align:start position:0% +monotone +decreasing and it's bounded below by + + align:start position:0% +decreasing and it's bounded below by + + + align:start position:0% +decreasing and it's bounded below by +zero + + align:start position:0% +zero + + + align:start position:0% +zero +and in fact bounded because + + align:start position:0% + + + + align:start position:0% + +bounded + + align:start position:0% + + + + align:start position:0% + +because c to the n an absolute value + + align:start position:0% +because c to the n an absolute value + + + align:start position:0% +because c to the n an absolute value +these are all positive it's equal to c + + align:start position:0% +these are all positive it's equal to c + + + align:start position:0% +these are all positive it's equal to c +to the n + + align:start position:0% +to the n + + + align:start position:0% +to the n +and + + align:start position:0% +and + + + align:start position:0% +and +c to the n is less than c to the n minus + + align:start position:0% +c to the n is less than c to the n minus + + + align:start position:0% +c to the n is less than c to the n minus +1 which is less than c to the n minus 2 + + align:start position:0% +1 which is less than c to the n minus 2 + + + align:start position:0% +1 which is less than c to the n minus 2 +so on and so on + + align:start position:0% +so on and so on + + + align:start position:0% +so on and so on +which is less than c + + align:start position:0% +which is less than c + + + align:start position:0% +which is less than c +so + + align:start position:0% +so + + + align:start position:0% +so +uh it's bounded + + align:start position:0% +uh it's bounded + + + align:start position:0% +uh it's bounded +um + + align:start position:0% +um + + + align:start position:0% +um +i guess i could have built that into + + align:start position:0% +i guess i could have built that into + + + align:start position:0% +i guess i could have built that into +this inequality and proved that as well + + align:start position:0% +this inequality and proved that as well + + + align:start position:0% +this inequality and proved that as well +but um that's okay + + align:start position:0% +but um that's okay + + + align:start position:0% +but um that's okay +so it has a limit so by + + align:start position:0% + + + + align:start position:0% + +by the previous theorem + + align:start position:0% + + + + align:start position:0% + +has a limit + + align:start position:0% +has a limit + + + align:start position:0% +has a limit +and i'll call it l + + align:start position:0% +and i'll call it l + + + align:start position:0% +and i'll call it l +and now what i want to show is that l is + + align:start position:0% +and now what i want to show is that l is + + + align:start position:0% +and now what i want to show is that l is +zero + + align:start position:0% + + + + align:start position:0% + +and how we'll do that is + + align:start position:0% +and how we'll do that is + + + align:start position:0% +and how we'll do that is +um one of uh + + align:start position:0% +um one of uh + + + align:start position:0% +um one of uh +these analysis tricks where are not + + align:start position:0% +these analysis tricks where are not + + + align:start position:0% +these analysis tricks where are not +really tricks but rather than show is l + + align:start position:0% +really tricks but rather than show is l + + + align:start position:0% +really tricks but rather than show is l +is directly equal to 0 we'll show that + + align:start position:0% +is directly equal to 0 we'll show that + + + align:start position:0% +is directly equal to 0 we'll show that +the absolute value of l is less than + + align:start position:0% +the absolute value of l is less than + + + align:start position:0% +the absolute value of l is less than +epsilon for every epsilon positive and + + align:start position:0% +epsilon for every epsilon positive and + + + align:start position:0% +epsilon for every epsilon positive and +therefore it has to be zero because it's + + align:start position:0% +therefore it has to be zero because it's + + + align:start position:0% +therefore it has to be zero because it's +just a fixed number + + align:start position:0% +just a fixed number + + + align:start position:0% +just a fixed number +um + + align:start position:0% + + + + align:start position:0% + +so let epsilon be positive again we're + + align:start position:0% +so let epsilon be positive again we're + + + align:start position:0% +so let epsilon be positive again we're +going to show that the absolute value of + + align:start position:0% +going to show that the absolute value of + + + align:start position:0% +going to show that the absolute value of +l which is just a fixed number is less + + align:start position:0% +l which is just a fixed number is less + + + align:start position:0% +l which is just a fixed number is less +than epsilon + + align:start position:0% +than epsilon + + + align:start position:0% +than epsilon +and therefore capital + + align:start position:0% +and therefore capital + + + align:start position:0% +and therefore capital +l has to be zero + + align:start position:0% + + + + align:start position:0% + +then + + align:start position:0% +then + + + align:start position:0% +then +there exists + + align:start position:0% +there exists + + + align:start position:0% +there exists +since this sequence converges + + align:start position:0% +since this sequence converges + + + align:start position:0% +since this sequence converges +an m a natural number + + align:start position:0% +an m a natural number + + + align:start position:0% +an m a natural number +such that for all n + + align:start position:0% +such that for all n + + + align:start position:0% +such that for all n +bigger than or equal to capital m + + align:start position:0% +bigger than or equal to capital m + + + align:start position:0% +bigger than or equal to capital m +c to the n minus l + + align:start position:0% +c to the n minus l + + + align:start position:0% +c to the n minus l +is less than + + align:start position:0% +is less than + + + align:start position:0% +is less than +1 minus c times epsilon + + align:start position:0% +1 minus c times epsilon + + + align:start position:0% +1 minus c times epsilon +over 2. + + align:start position:0% + + + + align:start position:0% + +now maybe you're wondering + + align:start position:0% +now maybe you're wondering + + + align:start position:0% +now maybe you're wondering +why i chose uh why why didn't i just use + + align:start position:0% +why i chose uh why why didn't i just use + + + align:start position:0% +why i chose uh why why didn't i just use +epsilon here well in the end + + align:start position:0% +epsilon here well in the end + + + align:start position:0% +epsilon here well in the end +it's just going to come out to + + align:start position:0% +it's just going to come out to + + + align:start position:0% +it's just going to come out to +this being less than epsilon an absolute + + align:start position:0% +this being less than epsilon an absolute + + + align:start position:0% +this being less than epsilon an absolute +value otherwise i would have come out + + align:start position:0% +value otherwise i would have come out + + + align:start position:0% +value otherwise i would have come out +with less than epsilon times some number + + align:start position:0% +with less than epsilon times some number + + + align:start position:0% +with less than epsilon times some number +and i did away with that number by + + align:start position:0% +and i did away with that number by + + + align:start position:0% +and i did away with that number by +choosing a different number here + + align:start position:0% +choosing a different number here + + + align:start position:0% +choosing a different number here +so + + align:start position:0% +so + + + align:start position:0% +so +now we compute + + align:start position:0% + + + + align:start position:0% + +that if i look at + + align:start position:0% +that if i look at + + + align:start position:0% +that if i look at +1 minus c times the absolute value of l + + align:start position:0% +1 minus c times the absolute value of l + + + align:start position:0% +1 minus c times the absolute value of l +this is equal to l minus c times l + + align:start position:0% +this is equal to l minus c times l + + + align:start position:0% +this is equal to l minus c times l +and this is less than or equal to + + align:start position:0% +and this is less than or equal to + + + align:start position:0% +and this is less than or equal to +l minus + + align:start position:0% + + + + align:start position:0% + +c to the capital m + + align:start position:0% +c to the capital m + + + align:start position:0% +c to the capital m +plus uh + + align:start position:0% + + + + align:start position:0% + +let's put a plus one plus c to the m + + align:start position:0% +let's put a plus one plus c to the m + + + align:start position:0% +let's put a plus one plus c to the m +plus one + + align:start position:0% +plus one + + + align:start position:0% +plus one +minus c to the l + + align:start position:0% +minus c to the l + + + align:start position:0% +minus c to the l +and by the triangle inequality this is + + align:start position:0% +and by the triangle inequality this is + + + align:start position:0% +and by the triangle inequality this is +less than or equal to l minus c to the + + align:start position:0% +less than or equal to l minus c to the + + + align:start position:0% +less than or equal to l minus c to the +n plus one plus + + align:start position:0% +n plus one plus + + + align:start position:0% +n plus one plus +now c to the n plus 1 minus c to the l + + align:start position:0% +now c to the n plus 1 minus c to the l + + + align:start position:0% +now c to the n plus 1 minus c to the l +so i can pull out a c which is positive + + align:start position:0% +so i can pull out a c which is positive + + + align:start position:0% +so i can pull out a c which is positive +so i can get + + align:start position:0% +so i can get + + + align:start position:0% +so i can get +l + + align:start position:0% +l + + + align:start position:0% +l +okay now + + align:start position:0% +okay now + + + align:start position:0% +okay now +n plus 1 is bigger than m + + align:start position:0% +n plus 1 is bigger than m + + + align:start position:0% +n plus 1 is bigger than m +so it satisfies this inequality + + align:start position:0% +so it satisfies this inequality + + + align:start position:0% +so it satisfies this inequality +and so does this one + + align:start position:0% +and so does this one + + + align:start position:0% +and so does this one +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and therefore this is less than + + align:start position:0% +and therefore this is less than + + + align:start position:0% +and therefore this is less than +epsilon over two times one minus c + + align:start position:0% +epsilon over two times one minus c + + + align:start position:0% +epsilon over two times one minus c +plus c times + + align:start position:0% +plus c times + + + align:start position:0% +plus c times +epsilon over two times one minus c and + + align:start position:0% +epsilon over two times one minus c and + + + align:start position:0% +epsilon over two times one minus c and +this is less than so c is less than 1 so + + align:start position:0% +this is less than so c is less than 1 so + + + align:start position:0% +this is less than so c is less than 1 so +this whole thing is less than epsilon + + align:start position:0% +this whole thing is less than epsilon + + + align:start position:0% +this whole thing is less than epsilon +over 2 times 1 minus c plus another + + align:start position:0% +over 2 times 1 minus c plus another + + + align:start position:0% +over 2 times 1 minus c plus another +epsilon over 2 so i get epsilon over 2 + + align:start position:0% + + + + align:start position:0% + +times 1 minus c + + align:start position:0% + + + + align:start position:0% + +and thus + + align:start position:0% + + + + align:start position:0% + +the absolute value of l is less than + + align:start position:0% +the absolute value of l is less than + + + align:start position:0% +the absolute value of l is less than +epsilon + + align:start position:0% +epsilon + + + align:start position:0% +epsilon +and since epsilon was arbitrary that + + align:start position:0% +and since epsilon was arbitrary that + + + align:start position:0% +and since epsilon was arbitrary that +implies the absolute value of l is equal + + align:start position:0% +implies the absolute value of l is equal + + + align:start position:0% +implies the absolute value of l is equal +to zero ie + + align:start position:0% +to zero ie + + + align:start position:0% +to zero ie +l is equal to zero + + align:start position:0% + + + + align:start position:0% + +okay so that's a + + align:start position:0% +okay so that's a + + + align:start position:0% +okay so that's a +very concrete + + align:start position:0% +very concrete + + + align:start position:0% +very concrete +um application of some of these theorems + + align:start position:0% +um application of some of these theorems + + + align:start position:0% +um application of some of these theorems +we've been proving which is really + + align:start position:0% +we've been proving which is really + + + align:start position:0% +we've been proving which is really +though + + align:start position:0% +though + + + align:start position:0% +though +i think the only real reason one proves + + align:start position:0% +i think the only real reason one proves + + + align:start position:0% +i think the only real reason one proves +theorems is + + align:start position:0% +theorems is + + + align:start position:0% +theorems is +you typically have a + + align:start position:0% +you typically have a + + + align:start position:0% +you typically have a +concrete + + align:start position:0% +concrete + + + align:start position:0% +concrete +example of something in mind that you + + align:start position:0% +example of something in mind that you + + + align:start position:0% +example of something in mind that you +want to study + + align:start position:0% + + + + align:start position:0% + +but in order to study it + + align:start position:0% +but in order to study it + + + align:start position:0% +but in order to study it +often requires some + + align:start position:0% +often requires some + + + align:start position:0% +often requires some +general machinery + + align:start position:0% + + + + align:start position:0% + +i.e theorems + + align:start position:0% + + + + align:start position:0% + +all right so now we'll + + align:start position:0% +all right so now we'll + + + align:start position:0% +all right so now we'll +talk a little bit about sequences + + align:start position:0% +talk a little bit about sequences + + + align:start position:0% +talk a little bit about sequences +obtained from + + align:start position:0% +obtained from + + + align:start position:0% +obtained from +other sequences um + + align:start position:0% +other sequences um + + + align:start position:0% +other sequences um +so these are called subsequences + + align:start position:0% + + + + align:start position:0% + +or sequence is obtained from + + align:start position:0% + + + + align:start position:0% + +a single sequence + + align:start position:0% +a single sequence + + + align:start position:0% +a single sequence +so what do i mean by this let me give + + align:start position:0% +so what do i mean by this let me give + + + align:start position:0% +so what do i mean by this let me give +you the the precise definition + + align:start position:0% + + + + align:start position:0% + +so we start off with + + align:start position:0% +so we start off with + + + align:start position:0% +so we start off with +a sequence + + align:start position:0% + + + + align:start position:0% + +and a increasing sequence of integers + + align:start position:0% + + + + align:start position:0% + +n sub k + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +let me just say what what this means + + align:start position:0% +let me just say what what this means + + + align:start position:0% +let me just say what what this means +rather than write out the word and then + + align:start position:0% +rather than write out the word and then + + + align:start position:0% +rather than write out the word and then +say what it means + + align:start position:0% +say what it means + + + align:start position:0% +say what it means +so this is + + align:start position:0% + + + + align:start position:0% + +the sequence of + + align:start position:0% + + + + align:start position:0% + +natural numbers + + align:start position:0% + + + + align:start position:0% + +which are strictly increasing n sub 1 is + + align:start position:0% +which are strictly increasing n sub 1 is + + + align:start position:0% +which are strictly increasing n sub 1 is +less than n sub 2 is less than n sub 3 + + align:start position:0% +less than n sub 2 is less than n sub 3 + + + align:start position:0% +less than n sub 2 is less than n sub 3 +and so on + + align:start position:0% + + + + align:start position:0% + +the new sequence + + align:start position:0% + + + + align:start position:0% + +x sub + + align:start position:0% +x sub + + + align:start position:0% +x sub +n sub k so now the index is not n + + align:start position:0% +n sub k so now the index is not n + + + align:start position:0% +n sub k so now the index is not n +but the index is k + + align:start position:0% + + + + align:start position:0% + +is called a + + align:start position:0% + + + + align:start position:0% + +subsequence + + align:start position:0% + + + + align:start position:0% + +of the original sequence x sub n + + align:start position:0% + + + + align:start position:0% + +all right so how should you view + + align:start position:0% +all right so how should you view + + + align:start position:0% +all right so how should you view +subsequences of a sequence + + align:start position:0% +subsequences of a sequence + + + align:start position:0% +subsequences of a sequence +you should think + + align:start position:0% + + + + align:start position:0% + +that i line up all the entries of x of + + align:start position:0% +that i line up all the entries of x of + + + align:start position:0% +that i line up all the entries of x of +my original sequence x sub n + + align:start position:0% +my original sequence x sub n + + + align:start position:0% +my original sequence x sub n +and then i just start + + align:start position:0% +and then i just start + + + align:start position:0% +and then i just start +uh picking entries + + align:start position:0% +uh picking entries + + + align:start position:0% +uh picking entries +out of the sequence so + + align:start position:0% +out of the sequence so + + + align:start position:0% +out of the sequence so +um + + align:start position:0% +um + + + align:start position:0% +um +but every time i make a choice i have to + + align:start position:0% +but every time i make a choice i have to + + + align:start position:0% +but every time i make a choice i have to +move to the right and make another + + align:start position:0% +move to the right and make another + + + align:start position:0% +move to the right and make another +choice + + align:start position:0% +choice + + + align:start position:0% +choice +okay that's that's + + align:start position:0% +okay that's that's + + + align:start position:0% +okay that's that's +what i was just saying there expresses + + align:start position:0% +what i was just saying there expresses + + + align:start position:0% +what i was just saying there expresses +this condition that um + + align:start position:0% +this condition that um + + + align:start position:0% +this condition that um +this sequence of natural numbers is + + align:start position:0% +this sequence of natural numbers is + + + align:start position:0% +this sequence of natural numbers is +increasing so i pick an entry in the + + align:start position:0% +increasing so i pick an entry in the + + + align:start position:0% +increasing so i pick an entry in the +sequence + + align:start position:0% +sequence + + + align:start position:0% +sequence +that's going to be my first guy + + align:start position:0% +that's going to be my first guy + + + align:start position:0% +that's going to be my first guy +the first element of my new subsequence + + align:start position:0% +the first element of my new subsequence + + + align:start position:0% +the first element of my new subsequence +and then i move to the right + + align:start position:0% +and then i move to the right + + + align:start position:0% +and then i move to the right +and + + align:start position:0% +and + + + align:start position:0% +and +maybe i pick the next one maybe i pick + + align:start position:0% +maybe i pick the next one maybe i pick + + + align:start position:0% +maybe i pick the next one maybe i pick +one three down i pick that one and then + + align:start position:0% +one three down i pick that one and then + + + align:start position:0% +one three down i pick that one and then +i move to the right of that one + + align:start position:0% +i move to the right of that one + + + align:start position:0% +i move to the right of that one +and pick a new one + + align:start position:0% +and pick a new one + + + align:start position:0% +and pick a new one +and then i move to the right of that one + + align:start position:0% +and then i move to the right of that one + + + align:start position:0% +and then i move to the right of that one +and pick another one + + align:start position:0% +and pick another one + + + align:start position:0% +and pick another one +okay so if you want to generate a + + align:start position:0% +okay so if you want to generate a + + + align:start position:0% +okay so if you want to generate a +subsequence from an original sequence + + align:start position:0% +subsequence from an original sequence + + + align:start position:0% +subsequence from an original sequence +you + + align:start position:0% +you + + + align:start position:0% +you +how do you think about this again line + + align:start position:0% +how do you think about this again line + + + align:start position:0% +how do you think about this again line +them all up start picking entries but + + align:start position:0% +them all up start picking entries but + + + align:start position:0% +them all up start picking entries but +every time you pick an entry you have to + + align:start position:0% +every time you pick an entry you have to + + + align:start position:0% +every time you pick an entry you have to +move to the right and pick in order to + + align:start position:0% +move to the right and pick in order to + + + align:start position:0% +move to the right and pick in order to +pick your next entry + + align:start position:0% +pick your next entry + + + align:start position:0% +pick your next entry +okay + + align:start position:0% + + + + align:start position:0% + +so let me give you some examples and + + align:start position:0% +so let me give you some examples and + + + align:start position:0% +so let me give you some examples and +non-examples + + align:start position:0% +non-examples + + + align:start position:0% +non-examples +so for example if + + align:start position:0% +so for example if + + + align:start position:0% +so for example if +our sequence our original sequence is + + align:start position:0% +our sequence our original sequence is + + + align:start position:0% +our sequence our original sequence is +one + + align:start position:0% +one + + + align:start position:0% +one +two three four five + + align:start position:0% +two three four five + + + align:start position:0% +two three four five +six + + align:start position:0% +six + + + align:start position:0% +six +and so on + + align:start position:0% +and so on + + + align:start position:0% +and so on +uh + + align:start position:0% +uh + + + align:start position:0% +uh +what would be examples of some + + align:start position:0% +what would be examples of some + + + align:start position:0% +what would be examples of some +subsequences + + align:start position:0% +subsequences + + + align:start position:0% +subsequences +the odd numbers 1 3 + + align:start position:0% +the odd numbers 1 3 + + + align:start position:0% +the odd numbers 1 3 +five seven + + align:start position:0% +five seven + + + align:start position:0% +five seven +nine and so on + + align:start position:0% +nine and so on + + + align:start position:0% +nine and so on +um + + align:start position:0% +um + + + align:start position:0% +um +you see how i'm taking the original + + align:start position:0% +you see how i'm taking the original + + + align:start position:0% +you see how i'm taking the original +sequence so this is + + align:start position:0% +sequence so this is + + + align:start position:0% +sequence so this is +x sub n i'm taking + + align:start position:0% +x sub n i'm taking + + + align:start position:0% +x sub n i'm taking +i'm just picking entries from the + + align:start position:0% +i'm just picking entries from the + + + align:start position:0% +i'm just picking entries from the +original sequence but every time i pick + + align:start position:0% +original sequence but every time i pick + + + align:start position:0% +original sequence but every time i pick +an entry i i move to the right and pick + + align:start position:0% +an entry i i move to the right and pick + + + align:start position:0% +an entry i i move to the right and pick +a new one so i picked one now i get to + + align:start position:0% +a new one so i picked one now i get to + + + align:start position:0% +a new one so i picked one now i get to +choose anything to the right of that i + + align:start position:0% +choose anything to the right of that i + + + align:start position:0% +choose anything to the right of that i +pick three now i have to choose i can + + align:start position:0% +pick three now i have to choose i can + + + align:start position:0% +pick three now i have to choose i can +choose anything to the right of that + + align:start position:0% +choose anything to the right of that + + + align:start position:0% +choose anything to the right of that +so in the language of this definition + + align:start position:0% +so in the language of this definition + + + align:start position:0% +so in the language of this definition +the increasing + + align:start position:0% + + + + align:start position:0% + +sequence of integers is just the odd + + align:start position:0% +sequence of integers is just the odd + + + align:start position:0% +sequence of integers is just the odd +integers so + + align:start position:0% +integers so + + + align:start position:0% +integers so +2k minus 1. so here + + align:start position:0% +2k minus 1. so here + + + align:start position:0% +2k minus 1. so here +x of n is equal to just n + + align:start position:0% +x of n is equal to just n + + + align:start position:0% +x of n is equal to just n +okay + + align:start position:0% + + + + align:start position:0% + +i could pick + + align:start position:0% +i could pick + + + align:start position:0% +i could pick +another subsequence would be uh the + + align:start position:0% +another subsequence would be uh the + + + align:start position:0% +another subsequence would be uh the +sequence of even numbers 2 4 6 + + align:start position:0% +sequence of even numbers 2 4 6 + + + align:start position:0% +sequence of even numbers 2 4 6 + + align:start position:0% + + + align:start position:0% +10. + + align:start position:0% +10. + + + align:start position:0% +10. +all right this is a subsequence of this + + align:start position:0% +all right this is a subsequence of this + + + align:start position:0% +all right this is a subsequence of this +original sequence here the increasing + + align:start position:0% +original sequence here the increasing + + + align:start position:0% +original sequence here the increasing +sequence of integers is 2k + + align:start position:0% + + + + align:start position:0% + +i could pick uh + + align:start position:0% +i could pick uh + + + align:start position:0% +i could pick uh +the subsequence could be the sequence of + + align:start position:0% +the subsequence could be the sequence of + + + align:start position:0% +the subsequence could be the sequence of +prime numbers 2 3 + + align:start position:0% +prime numbers 2 3 + + + align:start position:0% +prime numbers 2 3 + + align:start position:0% + + + align:start position:0% +7 11 + + align:start position:0% +7 11 + + + align:start position:0% +7 11 + + align:start position:0% + + + + align:start position:0% + +and the increasing + + align:start position:0% + + + + align:start position:0% + +yeah so i don't have a general formula + + align:start position:0% +yeah so i don't have a general formula + + + align:start position:0% +yeah so i don't have a general formula +for that + + align:start position:0% +for that + + + align:start position:0% +for that +good luck finding one + + align:start position:0% +good luck finding one + + + align:start position:0% +good luck finding one +but we'll just write this as + + align:start position:0% + + + + align:start position:0% + +kth prime number + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +now what would + + align:start position:0% +now what would + + + align:start position:0% +now what would +not be an example so these are examples + + align:start position:0% +not be an example so these are examples + + + align:start position:0% +not be an example so these are examples +of subsequences + + align:start position:0% + + + + align:start position:0% + +not examples of subsequences would be + + align:start position:0% +not examples of subsequences would be + + + align:start position:0% +not examples of subsequences would be +for example the sequence 1 1 1 1 + + align:start position:0% +for example the sequence 1 1 1 1 + + + align:start position:0% +for example the sequence 1 1 1 1 +1. this is not a subsequence of this + + align:start position:0% +1. this is not a subsequence of this + + + align:start position:0% +1. this is not a subsequence of this +original sequence okay + + align:start position:0% +original sequence okay + + + align:start position:0% +original sequence okay +remember i have i have a sequence of + + align:start position:0% +remember i have i have a sequence of + + + align:start position:0% +remember i have i have a sequence of +natural numbers which is increasing + + align:start position:0% +natural numbers which is increasing + + + align:start position:0% +natural numbers which is increasing +and x sub n sub k + + align:start position:0% + + + + align:start position:0% + +means that this new sequence is obtained + + align:start position:0% +means that this new sequence is obtained + + + align:start position:0% +means that this new sequence is obtained +from the old one by picking entries by + + align:start position:0% +from the old one by picking entries by + + + align:start position:0% +from the old one by picking entries by +picking an entry moving to the right + + align:start position:0% +picking an entry moving to the right + + + align:start position:0% +picking an entry moving to the right +picking the next entry moving to the + + align:start position:0% +picking the next entry moving to the + + + align:start position:0% +picking the next entry moving to the +right and picking the next entry + + align:start position:0% +right and picking the next entry + + + align:start position:0% +right and picking the next entry +here + + align:start position:0% +here + + + align:start position:0% +here +in order to get this sequence from this + + align:start position:0% +in order to get this sequence from this + + + align:start position:0% +in order to get this sequence from this +one i just stay on the first entry and + + align:start position:0% +one i just stay on the first entry and + + + align:start position:0% +one i just stay on the first entry and +keep picking it but that's + + align:start position:0% +keep picking it but that's + + + align:start position:0% +keep picking it but that's +not how a subsequence is defined + + align:start position:0% +not how a subsequence is defined + + + align:start position:0% +not how a subsequence is defined +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so here if you like this would mean n + + align:start position:0% +so here if you like this would mean n + + + align:start position:0% +so here if you like this would mean n +sub k + + align:start position:0% +sub k + + + align:start position:0% +sub k +is equal to one + + align:start position:0% +is equal to one + + + align:start position:0% +is equal to one +for all k and this is not a strictly + + align:start position:0% +for all k and this is not a strictly + + + align:start position:0% +for all k and this is not a strictly +increasing sequence of natural numbers + + align:start position:0% + + + + align:start position:0% + +uh or one one + + align:start position:0% +uh or one one + + + align:start position:0% +uh or one one +three three + + align:start position:0% +three three + + + align:start position:0% +three three +five five and so on that's also not so + + align:start position:0% +five five and so on that's also not so + + + align:start position:0% +five five and so on that's also not so +these are + + align:start position:0% + + + + align:start position:0% + +not + + align:start position:0% +not + + + align:start position:0% +not +subsequences of the original sequence + + align:start position:0% + + + + align:start position:0% + +given here + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +so i hope that's clear um + + align:start position:0% + + + + align:start position:0% + +now + + align:start position:0% + + + + align:start position:0% + +um + + align:start position:0% +um + + + align:start position:0% +um +i'm not saying i want to emphasize this + + align:start position:0% +i'm not saying i want to emphasize this + + + align:start position:0% +i'm not saying i want to emphasize this +i'm not saying + + align:start position:0% +i'm not saying + + + align:start position:0% +i'm not saying +that + + align:start position:0% +that + + + align:start position:0% +that +the number you pick + + align:start position:0% +the number you pick + + + align:start position:0% +the number you pick +time has to be different from the number + + align:start position:0% +time has to be different from the number + + + align:start position:0% +time has to be different from the number +you picked + + align:start position:0% +you picked + + + align:start position:0% +you picked +before meaning the value + + align:start position:0% +before meaning the value + + + align:start position:0% +before meaning the value +okay + + align:start position:0% +okay + + + align:start position:0% +okay +you couldn't have one one one one as + + align:start position:0% +you couldn't have one one one one as + + + align:start position:0% +you couldn't have one one one one as +a subsequence of this guy because one is + + align:start position:0% +a subsequence of this guy because one is + + + align:start position:0% +a subsequence of this guy because one is +only in the first entry you can't keep + + align:start position:0% +only in the first entry you can't keep + + + align:start position:0% +only in the first entry you can't keep +picking + + align:start position:0% +picking + + + align:start position:0% +picking +one entry you have to pick an entry and + + align:start position:0% +one entry you have to pick an entry and + + + align:start position:0% +one entry you have to pick an entry and +move to the next + + align:start position:0% +move to the next + + + align:start position:0% +move to the next +entry or the or one after that and pick + + align:start position:0% +entry or the or one after that and pick + + + align:start position:0% +entry or the or one after that and pick +that entry + + align:start position:0% +that entry + + + align:start position:0% +that entry +to obtain your sequence but that doesn't + + align:start position:0% +to obtain your sequence but that doesn't + + + align:start position:0% +to obtain your sequence but that doesn't +necessarily mean + + align:start position:0% +necessarily mean + + + align:start position:0% +necessarily mean +that those + + align:start position:0% +that those + + + align:start position:0% +that those +actual numbers in those entries have to + + align:start position:0% +actual numbers in those entries have to + + + align:start position:0% +actual numbers in those entries have to +be different so for example if i look at + + align:start position:0% +be different so for example if i look at + + + align:start position:0% +be different so for example if i look at +the sequence + + align:start position:0% + + + + align:start position:0% + +minus 1 1 + + align:start position:0% +minus 1 1 + + + align:start position:0% +minus 1 1 +minus 1 + + align:start position:0% +minus 1 + + + align:start position:0% +minus 1 +minus 1. + + align:start position:0% +minus 1. + + + align:start position:0% +minus 1. +1 meaning x of n is equal to minus 1 to + + align:start position:0% +1 meaning x of n is equal to minus 1 to + + + align:start position:0% +1 meaning x of n is equal to minus 1 to +the n + + align:start position:0% + + + + align:start position:0% + +then a perfectly good subsequence is + + align:start position:0% +then a perfectly good subsequence is + + + align:start position:0% +then a perfectly good subsequence is +given by + + align:start position:0% +given by + + + align:start position:0% +given by +minus 1 minus 1 minus 1 + + align:start position:0% +minus 1 minus 1 minus 1 + + + align:start position:0% +minus 1 minus 1 minus 1 +minus one + + align:start position:0% +minus one + + + align:start position:0% +minus one +where okay so it looks like i'm just + + align:start position:0% +where okay so it looks like i'm just + + + align:start position:0% +where okay so it looks like i'm just +picking one of the entries but really + + align:start position:0% +picking one of the entries but really + + + align:start position:0% +picking one of the entries but really +i'm not here + + align:start position:0% +i'm not here + + + align:start position:0% +i'm not here +the increasing sequence of what i'm + + align:start position:0% +the increasing sequence of what i'm + + + align:start position:0% +the increasing sequence of what i'm +doing here to get this new sequence i + + align:start position:0% +doing here to get this new sequence i + + + align:start position:0% +doing here to get this new sequence i +pick the first entry then i pick the + + align:start position:0% +pick the first entry then i pick the + + + align:start position:0% +pick the first entry then i pick the +third then i pick the fifth then i pick + + align:start position:0% +third then i pick the fifth then i pick + + + align:start position:0% +third then i pick the fifth then i pick +the seventh so + + align:start position:0% +the seventh so + + + align:start position:0% +the seventh so +n sub k equals two k minus one + + align:start position:0% +n sub k equals two k minus one + + + align:start position:0% +n sub k equals two k minus one +all right so all the actual numbers + + align:start position:0% +all right so all the actual numbers + + + align:start position:0% +all right so all the actual numbers +appearing in the sequence are the same + + align:start position:0% +appearing in the sequence are the same + + + align:start position:0% +appearing in the sequence are the same +but i'm actually picking + + align:start position:0% +but i'm actually picking + + + align:start position:0% +but i'm actually picking +different + + align:start position:0% +different + + + align:start position:0% +different +uh + + align:start position:0% +uh + + + align:start position:0% +uh +entries from the original sequence + + align:start position:0% +entries from the original sequence + + + align:start position:0% +entries from the original sequence +all right where they appear so this is + + align:start position:0% +all right where they appear so this is + + + align:start position:0% +all right where they appear so this is +also fine so is one one one one one + + align:start position:0% + + + + align:start position:0% + +this is nk equals two times k so these + + align:start position:0% +this is nk equals two times k so these + + + align:start position:0% +this is nk equals two times k so these +are all good sub uh sub sequences so + + align:start position:0% +are all good sub uh sub sequences so + + + align:start position:0% +are all good sub uh sub sequences so +these were subsequences of + + align:start position:0% +these were subsequences of + + + align:start position:0% +these were subsequences of +oops + + align:start position:0% +oops + + + align:start position:0% +oops +of the original sequence + + align:start position:0% +of the original sequence + + + align:start position:0% +of the original sequence +these are subsequences of + + align:start position:0% +these are subsequences of + + + align:start position:0% +these are subsequences of +uh this sequence + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% + + + + align:start position:0% + +all right so from a given sequence we + + align:start position:0% +all right so from a given sequence we + + + align:start position:0% +all right so from a given sequence we +obtain + + align:start position:0% +obtain + + + align:start position:0% +obtain +a new we we can obtain new sequences + + align:start position:0% +a new we we can obtain new sequences + + + align:start position:0% +a new we we can obtain new sequences +from this uh original sequence + + align:start position:0% +from this uh original sequence + + + align:start position:0% +from this uh original sequence +in this way + + align:start position:0% +in this way + + + align:start position:0% +in this way +so a natural question is to ask + + align:start position:0% +so a natural question is to ask + + + align:start position:0% +so a natural question is to ask +how does + + align:start position:0% +how does + + + align:start position:0% +how does +going from a sequence to a subsequence + + align:start position:0% + + + + align:start position:0% + +you know of not react but + + align:start position:0% + + + + align:start position:0% + +behave with respect to limits okay if + + align:start position:0% +behave with respect to limits okay if + + + align:start position:0% +behave with respect to limits okay if +the original sequence converges to a + + align:start position:0% +the original sequence converges to a + + + align:start position:0% +the original sequence converges to a +limit + + align:start position:0% +limit + + + align:start position:0% +limit +does a subsequence or does every + + align:start position:0% +does a subsequence or does every + + + align:start position:0% +does a subsequence or does every +subsequence converge to that limit as + + align:start position:0% +subsequence converge to that limit as + + + align:start position:0% +subsequence converge to that limit as +well + + align:start position:0% +well + + + align:start position:0% +well +and this shouldn't come as a surprise + + align:start position:0% +and this shouldn't come as a surprise + + + align:start position:0% +and this shouldn't come as a surprise +that that it does because + + align:start position:0% +that that it does because + + + align:start position:0% +that that it does because +you know all of the elements of the + + align:start position:0% +you know all of the elements of the + + + align:start position:0% +you know all of the elements of the +sequence are getting close all the + + align:start position:0% +sequence are getting close all the + + + align:start position:0% +sequence are getting close all the +entries of the sequence are getting + + align:start position:0% +entries of the sequence are getting + + + align:start position:0% +entries of the sequence are getting +close to a given number + + align:start position:0% +close to a given number + + + align:start position:0% +close to a given number +and a subsequence is just if you like + + align:start position:0% +and a subsequence is just if you like + + + align:start position:0% +and a subsequence is just if you like +picking certain ones along the way + + align:start position:0% +picking certain ones along the way + + + align:start position:0% +picking certain ones along the way +so + + align:start position:0% +so + + + align:start position:0% +so +certainly if i'm in a subsequence then + + align:start position:0% +certainly if i'm in a subsequence then + + + align:start position:0% +certainly if i'm in a subsequence then +as long as i'm far enough out in the + + align:start position:0% +as long as i'm far enough out in the + + + align:start position:0% +as long as i'm far enough out in the +subsequence i'll be close to that limit + + align:start position:0% +subsequence i'll be close to that limit + + + align:start position:0% +subsequence i'll be close to that limit +as well all right so if you didn't get + + align:start position:0% +as well all right so if you didn't get + + + align:start position:0% +as well all right so if you didn't get +all that rambling um + + align:start position:0% +all that rambling um + + + align:start position:0% +all that rambling um +i'll + + align:start position:0% +i'll + + + align:start position:0% +i'll +go ahead and state the theorem and prove + + align:start position:0% +go ahead and state the theorem and prove + + + align:start position:0% +go ahead and state the theorem and prove +it + + align:start position:0% + + + + align:start position:0% + +xn is a sequence which converges + + align:start position:0% +xn is a sequence which converges + + + align:start position:0% +xn is a sequence which converges +to x + + align:start position:0% + + + + align:start position:0% + +and x of n sub k is + + align:start position:0% + + + + align:start position:0% + +a subsequence of + + align:start position:0% + + + + align:start position:0% + +x of n + + align:start position:0% +x of n + + + align:start position:0% +x of n +then + + align:start position:0% +then + + + align:start position:0% +then +uh the subsequence converges to x as + + align:start position:0% +uh the subsequence converges to x as + + + align:start position:0% +uh the subsequence converges to x as +well + + align:start position:0% + + + + align:start position:0% + +limit as k goes to infinity of x sub n + + align:start position:0% +limit as k goes to infinity of x sub n + + + align:start position:0% +limit as k goes to infinity of x sub n +sub k + + align:start position:0% +sub k + + + align:start position:0% +sub k +equals x + + align:start position:0% +equals x + + + align:start position:0% +equals x +okay + + align:start position:0% + + + + align:start position:0% + +all right so + + align:start position:0% +all right so + + + align:start position:0% +all right so +um let me just start off by making a + + align:start position:0% +um let me just start off by making a + + + align:start position:0% +um let me just start off by making a +simple observation based on the fact + + align:start position:0% +simple observation based on the fact + + + align:start position:0% +simple observation based on the fact +that this increasing sequence + + align:start position:0% +that this increasing sequence + + + align:start position:0% +that this increasing sequence +that the n sub k's are an increasing + + align:start position:0% +that the n sub k's are an increasing + + + align:start position:0% +that the n sub k's are an increasing +sequence of natural numbers + + align:start position:0% + + + + align:start position:0% + +since + + align:start position:0% + + + + align:start position:0% + +n sub 1 is bigger than or equal to 1 is + + align:start position:0% +n sub 1 is bigger than or equal to 1 is + + + align:start position:0% +n sub 1 is bigger than or equal to 1 is +less than n sub 2 is less than n sub 3. + + align:start position:0% +less than n sub 2 is less than n sub 3. + + + align:start position:0% +less than n sub 2 is less than n sub 3. +so on + + align:start position:0% +so on + + + align:start position:0% +so on +this implies that + + align:start position:0% +this implies that + + + align:start position:0% +this implies that +for all k + + align:start position:0% +for all k + + + align:start position:0% +for all k +natural number + + align:start position:0% +natural number + + + align:start position:0% +natural number +n sub k + + align:start position:0% +n sub k + + + align:start position:0% +n sub k +is bigger than or equal to k + + align:start position:0% +is bigger than or equal to k + + + align:start position:0% +is bigger than or equal to k +all right + + align:start position:0% + + + + align:start position:0% + +um so this is not so hard to believe + + align:start position:0% +um so this is not so hard to believe + + + align:start position:0% +um so this is not so hard to believe +because n sub 1 has to be at least + + align:start position:0% +because n sub 1 has to be at least + + + align:start position:0% +because n sub 1 has to be at least +bigger than one n sub 2 has to be at + + align:start position:0% +bigger than one n sub 2 has to be at + + + align:start position:0% +bigger than one n sub 2 has to be at +least bigger than n sub 1 so it's either + + align:start position:0% +least bigger than n sub 1 so it's either + + + align:start position:0% +least bigger than n sub 1 so it's either +n sub 1 plus 1 or bigger + + align:start position:0% +n sub 1 plus 1 or bigger + + + align:start position:0% +n sub 1 plus 1 or bigger +and therefore you know you get by a + + align:start position:0% +and therefore you know you get by a + + + align:start position:0% +and therefore you know you get by a +simple induction argument which i'll + + align:start position:0% +simple induction argument which i'll + + + align:start position:0% +simple induction argument which i'll +leave to you you can prove that for all + + align:start position:0% +leave to you you can prove that for all + + + align:start position:0% +leave to you you can prove that for all +k a natural number + + align:start position:0% +k a natural number + + + align:start position:0% +k a natural number +n sub k is bigger than or equal to k + + align:start position:0% +n sub k is bigger than or equal to k + + + align:start position:0% +n sub k is bigger than or equal to k +the induct on uh k + + align:start position:0% + + + + align:start position:0% + +all right + + align:start position:0% + + + + align:start position:0% + +so we want to prove that this sequence + + align:start position:0% +so we want to prove that this sequence + + + align:start position:0% +so we want to prove that this sequence +converges to x and we're going to do + + align:start position:0% +converges to x and we're going to do + + + align:start position:0% +converges to x and we're going to do +that using the only means we have so + + align:start position:0% +that using the only means we have so + + + align:start position:0% +that using the only means we have so +this is just some arbitrary subsequence + + align:start position:0% +this is just some arbitrary subsequence + + + align:start position:0% +this is just some arbitrary subsequence +of x sub n all we have is the definition + + align:start position:0% +of x sub n all we have is the definition + + + align:start position:0% +of x sub n all we have is the definition +to use + + align:start position:0% + + + + align:start position:0% + +so we're going to now prove this so we + + align:start position:0% +so we're going to now prove this so we + + + align:start position:0% +so we're going to now prove this so we +have to show for all epsilon positive + + align:start position:0% +have to show for all epsilon positive + + + align:start position:0% +have to show for all epsilon positive +blah blah blah so the first thing we + + align:start position:0% +blah blah blah so the first thing we + + + align:start position:0% +blah blah blah so the first thing we +have to do is let epsilon be positive + + align:start position:0% +have to do is let epsilon be positive + + + align:start position:0% +have to do is let epsilon be positive +now we'll use the fact that x sub n + + align:start position:0% +now we'll use the fact that x sub n + + + align:start position:0% +now we'll use the fact that x sub n +converges to x + + align:start position:0% + + + + align:start position:0% + +sub x n converges to x + + align:start position:0% +sub x n converges to x + + + align:start position:0% +sub x n converges to x +there exists a natural number + + align:start position:0% +there exists a natural number + + + align:start position:0% +there exists a natural number +m + + align:start position:0% +m + + + align:start position:0% +m +not + + align:start position:0% +not + + + align:start position:0% +not +such that for all n bigger than or equal + + align:start position:0% +such that for all n bigger than or equal + + + align:start position:0% +such that for all n bigger than or equal +to m naught + + align:start position:0% + + + + align:start position:0% + +um + + align:start position:0% + + + + align:start position:0% + +x sub n minus x absolute value is less + + align:start position:0% +x sub n minus x absolute value is less + + + align:start position:0% +x sub n minus x absolute value is less +than epsilon + + align:start position:0% +than epsilon + + + align:start position:0% +than epsilon +okay + + align:start position:0% +okay + + + align:start position:0% +okay +this m sub not we'll choose for our + + align:start position:0% +this m sub not we'll choose for our + + + align:start position:0% +this m sub not we'll choose for our +subsequence + + align:start position:0% + + + + align:start position:0% + +choose m to equal m sub naught + + align:start position:0% + + + + align:start position:0% + +so now we need to show that this capital + + align:start position:0% +so now we need to show that this capital + + + align:start position:0% +so now we need to show that this capital +m works for our subsequence meaning if k + + align:start position:0% +m works for our subsequence meaning if k + + + align:start position:0% +m works for our subsequence meaning if k +is bigger than or equal to capital m + + align:start position:0% +is bigger than or equal to capital m + + + align:start position:0% +is bigger than or equal to capital m +then + + align:start position:0% +then + + + align:start position:0% +then +x of n sub k minus x is uh + + align:start position:0% +x of n sub k minus x is uh + + + align:start position:0% +x of n sub k minus x is uh +an absolute value less than epsilon but + + align:start position:0% +an absolute value less than epsilon but + + + align:start position:0% +an absolute value less than epsilon but +this just follows from from this fact + + align:start position:0% +this just follows from from this fact + + + align:start position:0% +this just follows from from this fact +right so + + align:start position:0% +right so + + + align:start position:0% +right so +then if k + + align:start position:0% +then if k + + + align:start position:0% +then if k +is bigger than or equal to m this + + align:start position:0% +is bigger than or equal to m this + + + align:start position:0% +is bigger than or equal to m this +implies + + align:start position:0% +implies + + + align:start position:0% +implies +by this inequality + + align:start position:0% + + + + align:start position:0% + +n sub k is bigger than or equal to m + + align:start position:0% +n sub k is bigger than or equal to m + + + align:start position:0% +n sub k is bigger than or equal to m +which remember is equal to m sub naught + + align:start position:0% +which remember is equal to m sub naught + + + align:start position:0% +which remember is equal to m sub naught +so n sub k is some integer + + align:start position:0% +so n sub k is some integer + + + align:start position:0% +so n sub k is some integer +so natural number bigger than or equal + + align:start position:0% +so natural number bigger than or equal + + + align:start position:0% +so natural number bigger than or equal +to m sub naught + + align:start position:0% +to m sub naught + + + align:start position:0% +to m sub naught +so that implies by this inequality that + + align:start position:0% +so that implies by this inequality that + + + align:start position:0% +so that implies by this inequality that +x of n sub k + + align:start position:0% +x of n sub k + + + align:start position:0% +x of n sub k +minus x an absolute value is less than + + align:start position:0% +minus x an absolute value is less than + + + align:start position:0% +minus x an absolute value is less than +epsilon + + align:start position:0% + + + + align:start position:0% + +okay \ No newline at end of file diff --git a/4EcVts56MCU.txt b/4EcVts56MCU.txt new file mode 100644 index 0000000000000000000000000000000000000000..a331305c3329d1adca787bbf584544b2c0340938 --- /dev/null +++ b/4EcVts56MCU.txt @@ -0,0 +1,1171 @@ +align:start position:0% + +why does shape matter + + align:start position:0% +why does shape matter + + + align:start position:0% +why does shape matter +i told you shape mattered in the very + + align:start position:0% +i told you shape mattered in the very + + + align:start position:0% +i told you shape mattered in the very +beginning + + align:start position:0% +beginning + + + align:start position:0% +beginning +but why does it matter right let's say + + align:start position:0% +but why does it matter right let's say + + + align:start position:0% +but why does it matter right let's say +isn't it just important to know what the + + align:start position:0% +isn't it just important to know what the + + + align:start position:0% +isn't it just important to know what the +chemistry is + + align:start position:0% +chemistry is + + + align:start position:0% +chemistry is +and not the actual shape why does the + + align:start position:0% +and not the actual shape why does the + + + align:start position:0% +and not the actual shape why does the +shape matter and so i thought i would + + align:start position:0% +shape matter and so i thought i would + + + align:start position:0% +shape matter and so i thought i would +give you an example + + align:start position:0% +give you an example + + + align:start position:0% +give you an example +of that um with smell + + align:start position:0% +of that um with smell + + + align:start position:0% +of that um with smell +and and i yeah right + + align:start position:0% +and and i yeah right + + + align:start position:0% +and and i yeah right +exactly and i actually think we should + + align:start position:0% +exactly and i actually think we should + + + align:start position:0% +exactly and i actually think we should +do this more often i + + align:start position:0% +do this more often i + + + align:start position:0% +do this more often i +you know i feel like this is inspiring + + align:start position:0% +you know i feel like this is inspiring + + + align:start position:0% +you know i feel like this is inspiring +we talk about stopping and smelling the + + align:start position:0% +we talk about stopping and smelling the + + + align:start position:0% +we talk about stopping and smelling the +flowers + + align:start position:0% +flowers + + + align:start position:0% +flowers +but do we actually do it and look at + + align:start position:0% +but do we actually do it and look at + + + align:start position:0% +but do we actually do it and look at +that they've got + + align:start position:0% +that they've got + + + align:start position:0% +that they've got +you know one armor on the other this is + + align:start position:0% +you know one armor on the other this is + + + align:start position:0% +you know one armor on the other this is +a moment + + align:start position:0% +a moment + + + align:start position:0% +a moment +you can't share this moment on instagram + + align:start position:0% +you can't share this moment on instagram + + + align:start position:0% +you can't share this moment on instagram +you have to put your phone down and be + + align:start position:0% +you have to put your phone down and be + + + align:start position:0% +you have to put your phone down and be +there to have this moment + + align:start position:0% +there to have this moment + + + align:start position:0% +there to have this moment +and i highly encourage you to be + + align:start position:0% +and i highly encourage you to be + + + align:start position:0% +and i highly encourage you to be +inspired by this + + align:start position:0% +inspired by this + + + align:start position:0% +inspired by this +now smell and taste are actually related + + align:start position:0% +now smell and taste are actually related + + + align:start position:0% +now smell and taste are actually related +and smell is um + + align:start position:0% +and smell is um + + + align:start position:0% +and smell is um +you know it's actually a fascinating + + align:start position:0% +you know it's actually a fascinating + + + align:start position:0% +you know it's actually a fascinating +thing it we can smell about ten thousand + + align:start position:0% +thing it we can smell about ten thousand + + + align:start position:0% +thing it we can smell about ten thousand +uh different smells um + + align:start position:0% +uh different smells um + + + align:start position:0% +uh different smells um +it's remarkable uh a dog can smell + + align:start position:0% +it's remarkable uh a dog can smell + + + align:start position:0% +it's remarkable uh a dog can smell +between ten and a hundred thousand times + + align:start position:0% +between ten and a hundred thousand times + + + align:start position:0% +between ten and a hundred thousand times +more right so if you if you do the + + align:start position:0% +more right so if you if you do the + + + align:start position:0% +more right so if you if you do the +analogy that people do with vision + + align:start position:0% +analogy that people do with vision + + + align:start position:0% +analogy that people do with vision +we can see a third of a mile dog could + + align:start position:0% +we can see a third of a mile dog could + + + align:start position:0% +we can see a third of a mile dog could +see about 3 000 miles + + align:start position:0% +see about 3 000 miles + + + align:start position:0% +see about 3 000 miles +right that's pretty cool + + align:start position:0% + + + + align:start position:0% + +but the question is why do we smell how + + align:start position:0% +but the question is why do we smell how + + + align:start position:0% +but the question is why do we smell how +do we smell + + align:start position:0% +do we smell + + + align:start position:0% +do we smell +how do we taste and it turns out that + + align:start position:0% +how do we taste and it turns out that + + + align:start position:0% +how do we taste and it turns out that +the way that we distinguish from one + + align:start position:0% +the way that we distinguish from one + + + align:start position:0% +the way that we distinguish from one +smell + + align:start position:0% +smell + + + align:start position:0% +smell +or in one taste in another has to do + + align:start position:0% +or in one taste in another has to do + + + align:start position:0% +or in one taste in another has to do +with the shape of the molecule + + align:start position:0% +with the shape of the molecule + + + align:start position:0% +with the shape of the molecule +and so just like a key right in it with + + align:start position:0% +and so just like a key right in it with + + + align:start position:0% +and so just like a key right in it with +a key there's not + + align:start position:0% +a key there's not + + + align:start position:0% +a key there's not +it's all the same material it's the same + + align:start position:0% +it's all the same material it's the same + + + align:start position:0% +it's all the same material it's the same +chemistry in the key but the shape + + align:start position:0% +chemistry in the key but the shape + + + align:start position:0% +chemistry in the key but the shape +is different that can unlock the door or + + align:start position:0% +is different that can unlock the door or + + + align:start position:0% +is different that can unlock the door or +not that is literally how + + align:start position:0% +not that is literally how + + + align:start position:0% +not that is literally how +our receptor cells work for taste and + + align:start position:0% +our receptor cells work for taste and + + + align:start position:0% +our receptor cells work for taste and +smell + + align:start position:0% +smell + + + align:start position:0% +smell +um this is a cartoon i found that i kind + + align:start position:0% +um this is a cartoon i found that i kind + + + align:start position:0% +um this is a cartoon i found that i kind +of like see okay + + align:start position:0% +of like see okay + + + align:start position:0% +of like see okay +shapes circles squares + + align:start position:0% +shapes circles squares + + + align:start position:0% +shapes circles squares +right uh okay and some shapes come in + + align:start position:0% +right uh okay and some shapes come in + + + align:start position:0% +right uh okay and some shapes come in +and they make happiness + + align:start position:0% +and they make happiness + + + align:start position:0% +and they make happiness +happiness flowers and stuff cheat i + + align:start position:0% +happiness flowers and stuff cheat i + + + align:start position:0% +happiness flowers and stuff cheat i +don't know is cheese happy it looks + + align:start position:0% +don't know is cheese happy it looks + + + align:start position:0% +don't know is cheese happy it looks +neutral + + align:start position:0% +neutral + + + align:start position:0% +neutral +i would get happy with cheese but anyway + + align:start position:0% +i would get happy with cheese but anyway + + + align:start position:0% +i would get happy with cheese but anyway +uh fish for some reason but you know it + + align:start position:0% +uh fish for some reason but you know it + + + align:start position:0% +uh fish for some reason but you know it +depends + + align:start position:0% +depends + + + align:start position:0% +depends +and but it's shape dependent now the + + align:start position:0% +and but it's shape dependent now the + + + align:start position:0% +and but it's shape dependent now the +thing is taste works that way too so + + align:start position:0% +thing is taste works that way too so + + + align:start position:0% +thing is taste works that way too so +this is what's happening in your tongue + + align:start position:0% +this is what's happening in your tongue + + + align:start position:0% +this is what's happening in your tongue +you've got these these uh these taste + + align:start position:0% +you've got these these uh these taste + + + align:start position:0% +you've got these these uh these taste +buds we've all heard + + align:start position:0% +buds we've all heard + + + align:start position:0% +buds we've all heard +the word taste bud right but what is + + align:start position:0% +the word taste bud right but what is + + + align:start position:0% +the word taste bud right but what is +really going on + + align:start position:0% +really going on + + + align:start position:0% +really going on +what is really going on is a combination + + align:start position:0% +what is really going on is a combination + + + align:start position:0% +what is really going on is a combination +of chemistry + + align:start position:0% +of chemistry + + + align:start position:0% +of chemistry +and shape recognition um so + + align:start position:0% +and shape recognition um so + + + align:start position:0% +and shape recognition um so +so the taste bud if you look at the + + align:start position:0% +so the taste bud if you look at the + + + align:start position:0% +so the taste bud if you look at the +taste bud that's inside of the little + + align:start position:0% +taste bud that's inside of the little + + + align:start position:0% +taste bud that's inside of the little +these little pores inside your tongue + + align:start position:0% +these little pores inside your tongue + + + align:start position:0% +these little pores inside your tongue +there's a blow up of it + + align:start position:0% +there's a blow up of it + + + align:start position:0% +there's a blow up of it +and so this is what the surface of your + + align:start position:0% +and so this is what the surface of your + + + align:start position:0% +and so this is what the surface of your +tongue looks like and there's a little + + align:start position:0% +tongue looks like and there's a little + + + align:start position:0% +tongue looks like and there's a little +pore + + align:start position:0% +pore + + + align:start position:0% +pore +and there's little filters in there that + + align:start position:0% +and there's little filters in there that + + + align:start position:0% +and there's little filters in there that +help certain molecules you know kind of + + align:start position:0% +help certain molecules you know kind of + + + align:start position:0% +help certain molecules you know kind of +get in there + + align:start position:0% +get in there + + + align:start position:0% +get in there +and what happens when they get in there + + align:start position:0% +and what happens when they get in there + + + align:start position:0% +and what happens when they get in there +well what happens is you've got these + + align:start position:0% +well what happens is you've got these + + + align:start position:0% +well what happens is you've got these +taste receptor cells + + align:start position:0% +taste receptor cells + + + align:start position:0% +taste receptor cells +that are like lock key pairs they + + align:start position:0% +that are like lock key pairs they + + + align:start position:0% +that are like lock key pairs they +actually only look at like the circle or + + align:start position:0% +actually only look at like the circle or + + + align:start position:0% +actually only look at like the circle or +the diamond and they can tell you which + + align:start position:0% +the diamond and they can tell you which + + + align:start position:0% +the diamond and they can tell you which +one is which + + align:start position:0% +one is which + + + align:start position:0% +one is which +and that's a major part of how we + + align:start position:0% +and that's a major part of how we + + + align:start position:0% +and that's a major part of how we +distinguish from one shape + + align:start position:0% +distinguish from one shape + + + align:start position:0% +distinguish from one shape +uh to another and it's actually so um + + align:start position:0% +uh to another and it's actually so um + + + align:start position:0% +uh to another and it's actually so um +uh it's it's it goes back a long way why + + align:start position:0% +uh it's it's it goes back a long way why + + + align:start position:0% +uh it's it's it goes back a long way why +because shape and smell are are + + align:start position:0% +because shape and smell are are + + + align:start position:0% +because shape and smell are are +literally uh survival they are literally + + align:start position:0% +literally uh survival they are literally + + + align:start position:0% +literally uh survival they are literally +like you can + + align:start position:0% +like you can + + + align:start position:0% +like you can +you know if you taste something and it's + + align:start position:0% +you know if you taste something and it's + + + align:start position:0% +you know if you taste something and it's +and it and it + + align:start position:0% +and it and it + + + align:start position:0% +and it and it +tastes poisonous don't eat it you live + + align:start position:0% +tastes poisonous don't eat it you live + + + align:start position:0% +tastes poisonous don't eat it you live +right so it is it is a very emotional + + align:start position:0% +right so it is it is a very emotional + + + align:start position:0% +right so it is it is a very emotional +thing + + align:start position:0% +thing + + + align:start position:0% +thing +to smell and taste because it is + + align:start position:0% +to smell and taste because it is + + + align:start position:0% +to smell and taste because it is +actually coupled to + + align:start position:0% +actually coupled to + + + align:start position:0% +actually coupled to +to your very survival and democracy + + align:start position:0% +to your very survival and democracy + + + align:start position:0% +to your very survival and democracy +himself democritus + + align:start position:0% +himself democritus + + + align:start position:0% +himself democritus +democr our friend democritus said that + + align:start position:0% +democr our friend democritus said that + + + align:start position:0% +democr our friend democritus said that +shape + + align:start position:0% +shape + + + align:start position:0% +shape +must be involved he thought that because + + align:start position:0% +must be involved he thought that because + + + align:start position:0% +must be involved he thought that because +things that taste bitter + + align:start position:0% +things that taste bitter + + + align:start position:0% +things that taste bitter +are sharp that the bitter molecules were + + align:start position:0% +are sharp that the bitter molecules were + + + align:start position:0% +are sharp that the bitter molecules were +sharp + + align:start position:0% +sharp + + + align:start position:0% +sharp +they must have sharpness to them and + + align:start position:0% +they must have sharpness to them and + + + align:start position:0% +they must have sharpness to them and +like like shards of glass + + align:start position:0% +like like shards of glass + + + align:start position:0% +like like shards of glass +that's how he imagined it and the sweet + + align:start position:0% +that's how he imagined it and the sweet + + + align:start position:0% +that's how he imagined it and the sweet +molecules were sort of these soft + + align:start position:0% +molecules were sort of these soft + + + align:start position:0% +molecules were sort of these soft +fluffy spheres right but that's not that + + align:start position:0% +fluffy spheres right but that's not that + + + align:start position:0% +fluffy spheres right but that's not that +far + + align:start position:0% +far + + + align:start position:0% +far +off from being sort of what happens + + align:start position:0% +off from being sort of what happens + + + align:start position:0% +off from being sort of what happens +a little bit but when we look at like + + align:start position:0% +a little bit but when we look at like + + + align:start position:0% +a little bit but when we look at like +you know glucose and and quinine we say + + align:start position:0% +you know glucose and and quinine we say + + + align:start position:0% +you know glucose and and quinine we say +okay those are very + + align:start position:0% +okay those are very + + + align:start position:0% +okay those are very +different chemistries so it might not be + + align:start position:0% +different chemistries so it might not be + + + align:start position:0% +different chemistries so it might not be +as obvious + + align:start position:0% +as obvious + + + align:start position:0% +as obvious +why one of them tastes so different than + + align:start position:0% +why one of them tastes so different than + + + align:start position:0% +why one of them tastes so different than +the other + + align:start position:0% +the other + + + align:start position:0% +the other +but check out this example this is the + + align:start position:0% +but check out this example this is the + + + align:start position:0% +but check out this example this is the +same molecule the carbonic molecule + + align:start position:0% +same molecule the carbonic molecule + + + align:start position:0% +same molecule the carbonic molecule +that is called an enantiomer which means + + align:start position:0% +that is called an enantiomer which means + + + align:start position:0% +that is called an enantiomer which means +that it has + + align:start position:0% +that it has + + + align:start position:0% +that it has +handedness it's the exact same chemical + + align:start position:0% +handedness it's the exact same chemical + + + align:start position:0% +handedness it's the exact same chemical +formula and the exact same structure + + align:start position:0% +formula and the exact same structure + + + align:start position:0% +formula and the exact same structure +except for one is like this and one is + + align:start position:0% +except for one is like this and one is + + + align:start position:0% +except for one is like this and one is +like that + + align:start position:0% +like that + + + align:start position:0% +like that +that's handedness right and that + + align:start position:0% +that's handedness right and that + + + align:start position:0% +that's handedness right and that +difference makes one of them taste and + + align:start position:0% +difference makes one of them taste and + + + align:start position:0% +difference makes one of them taste and +smell like experiment and the other like + + align:start position:0% +smell like experiment and the other like + + + align:start position:0% +smell like experiment and the other like +caraway seeds + + align:start position:0% +caraway seeds + + + align:start position:0% +caraway seeds +right it's incredible it's entire it + + align:start position:0% +right it's incredible it's entire it + + + align:start position:0% +right it's incredible it's entire it +means that in our tongues in our noses + + align:start position:0% +means that in our tongues in our noses + + + align:start position:0% +means that in our tongues in our noses +we must have + + align:start position:0% +we must have + + + align:start position:0% +we must have +chiral uh the ability to to determine + + align:start position:0% +chiral uh the ability to to determine + + + align:start position:0% +chiral uh the ability to to determine +the chirality + + align:start position:0% +the chirality + + + align:start position:0% +the chirality +it's pretty cool right so shape is + + align:start position:0% +it's pretty cool right so shape is + + + align:start position:0% +it's pretty cool right so shape is +critical and this is one example of why + + align:start position:0% +critical and this is one example of why + + + align:start position:0% +critical and this is one example of why +this is one example why okay + + align:start position:0% +this is one example why okay + + + align:start position:0% +this is one example why okay +you \ No newline at end of file diff --git a/4OinSH6sAUo.txt b/4OinSH6sAUo.txt new file mode 100644 index 0000000000000000000000000000000000000000..177c93543c42b4fc8a582cb9e11c66724c3a34a5 --- /dev/null +++ b/4OinSH6sAUo.txt @@ -0,0 +1,4415 @@ +The following +content is provided + +under a Creative +Commons license. + +Your support will help MIT +OpenCourseWare continue + +to offer high quality +educational resources for free. + +To make a donation or to +view additional materials + +from hundreds of MIT courses, +visit MIT OpenCourseWare + +at ocw.mit.edu. + +PROFESSOR: So I want to begin +by reviewing a little bit what + +I said last time in terms +of this overview lecture. + +And then we'll finish +the overview lecture. + +So summary of last lecture +is actually on five slides. + +It's not all on this one slide. + +We started by talking about the +standard Big Bang, by which I + +mean the Big Bang without +thinking about inflation. + +And I pointed out that +it really describes + +only the aftermath of a bang. + +It begins with the +description of the universe + +as a hot, dense soup of +particles which more or less + +uniformly fills the +entire available space, + +and the entire system +is already expanding. + +Cosmic inflation is a prequel +to the conventional Big Bang + +story. + +It describes how +repulsive gravity, which + +in the context of +general relativity, + +can happen as a consequence +of negative pressure. + +This repulsive +gravity could have + +driven a tiny patch +of the early universe + +into a gigantic burst of +exponential expansion. + +And our visible +universe would then + +be the aftermath of that event. + +As this happened, the +total energy of this patch + +would be very small and +could even be identically 0. + +And the way that's possible +is caused by the fact + +that the gravitational +field that fills the space + +has a negative +contribution to the energy. + +And as far as we can tell +in our real universe, + +there are about +equal to each other. + +They could cancel each other +exactly as far as we can tell. + +So the total energy +could in fact + +be exactly zero, +which is what allows + +one to build a huge +universe starting + +from either nothing +or almost nothing. + +Inflation. + +The next item is +evidence for inflation. + +Why do we think there's +at least a good chance + +that our universe +underwent inflation? + +And I pointed out three items. + +The first was that inflation +could explain the large scale + +uniformity that we +observe in the universe + +and that large +scale uniformity is + +seen most clearly in the +cosmic microwave background + +radiation, which is observed +to be uniform to one + +part in $100,000, that is same +intensity all across the sky + +no matter what direction +you look, once you account + +for the Earth's motion, +to an accuracy of one part + +in 100,000. + +Secondly, inflation can explain +a rather remarkable fact + +about this quantity +omega, where omega + +is defined as the actual +mass density of the universe + +rho divided by rho critical, +the critical mass density which + +is the density that would make +the universe precisely flat. + +The statement that that +ratio is equal to 1 we know + +is accurate to about 15 +decimal places at one second + +after the Big Bang. + +And prior to inflation, +we didn't really + +have any explanation +for that at all. + +But inflation +drives omega to one + +and gives us an explanation +for why, therefore, + +started out so +extraordinarily close to 1. + +And in fact, it +makes a prediction. + +We'd expect that if +inflation is right, + +omega should still be one today. + +And we now have measured omega +to be 1.0010 plus or minus + +0.0065, which I +think is fabulous. + +Finally, inflation +gives an explanation + +for the inhomogeneities +that we see in the universe. + +It explains them as +quantum fluctuations which + +happened during the inflationary +process and, most importantly + +really, as inflation was +ending, the quantum fluctuations + +cause inflation to go +on for a little bit + +longer in some +regions than others. + +And that sets up +these inhomogeneities. + +Today, we can see +these inhomogeneities + +most accurately. + +inhomogeneities, of course, are +huge at the level of galaxies, + +so they're obvious. + +But it's hard to connect +them to the early universe. + +So we can make our most +precise comparison between what + +we observe and theories +of the early universe + +by making careful observations +of the cosmic background + +radiation itself, which has +these ripples in the intensity, + +It is not quite uniform. + +There really are ripples at the +level of one part in 100,000, + +which can now be observed. + +And inflation makes +a clear prediction + +for the spectrum +of those ripples, + +how the intensity should +vary with wavelength. + +And I showed you this graph last +time from the Planck satellite. + +The agreement between the +prediction and the theory + +is really marvelous. + +So we'll be coming back to that +near the end of the course. + +Finally, in the last +lecture, I began + +to talk about inflation and +the possible implications + +for a multiverse, the idea that +our universe might be embedded + +in a much larger +thing consisting + +of many universes, which +we call a multiverse. + +And the key point is that +most inflation models + +tend to become eternal. + +And that is once inflation +starts, it never stops. + +And the reason for +that, basically, + +is that the metastable +material, this repulsive gravity + +material that's causing +the inflation, decays, + +but it also +exponentially expands. + +And for typical models, +the exponential expansion + +completely overpowers the decay. + +So even though it's an +unstable material that decays, + +the total volume of it actually +increases exponentially + +with time rather than decreases. + +Decays happen however, +and wherever decay happen, + +it forms what we call +a pocket universe. + +We would be living in one +of those pocket universes. + +And the number of +pocket universes + +grows exponentially with time as +the whole system grows and goes + +on, as far as we +can tell, forever. + +And that is the picture +of the multiverse + +that inflation tends to lead to. + +Finally, this is my +last summary slide + +and then we'll +start new material. + +At the very end of +lecture, I talked + +about a problem, which is very +important in our present day + +thinking about +physics and cosmology, + +and that is the nightmare that +this discovery of dark energy + +leads to. + +What was discovered +at about 1998 + +is that the expansion +of the universe + +is not slowing down under +the influence of gravity + +as one might expect, +but Instead, it's + +actually accelerating. + +The universe is expanding +faster and faster. + +And that indicates +that space today + +is filled with some repulsive +gravity material, which + +we call the dark energy. + +And the simplest interpretation +of the dark energy + +is that it simply vacuum energy, +the energy of empty space. + +Space does have an +energy density that + +have exactly the +properties that we observe, + +so it seems natural to +draw that connection. + +Vacuum energy, at first, +might seem surprising. + +If a vacuum's empty, why should +it have any mass density? + +But in a quantum field theory, +it's really not surprising + +because in a quantum +field theory, + +the vacuum is really not empty. + +In a quantum field +theory, there's + +no such thing as +actual emptiness. + +Instead, in the vacuum, one has +constant quantum fluctuations + +of fields. + +And in our current theory +of particle physics, + +the standard model +of particle physics, + +there's even one particular +field called the Higgs field, + +which has a non-zero +mean value in the vacuum + +besides fluctuations. + +So the vacuum is a +very complicated state. + +What makes it the +vacuum is simply + +that it's alleged to be the +state of lowest possible energy + +density, but that +doesn't have to be zero + +and doesn't even +look like there's + +any reason why it +should be zero. + +So there's no problem +buying the fact + +that maybe the vacuum does +have a non-zero energy density. + +The problem comes +about though when + +we try to understand the +magnitude of this vacuum + +energy. + +If it was going to have +a vacuum energy density, + +we'd expect it to be +vastly larger than what + +is observed in the +form of the expansion + +acceleration of the universe. + +So a typical order of magnitude +in the particle physics + +model for the vacuum +energy is, in fact, + +about a full 120 +orders of magnitude + +larger than the +number that's implied + +by the acceleration +of the universe. + +So that is a big problem. + +I began to talk about a possible +resolution to that problem. + +It's only a possible resolution. + +Nobody has really +settled on this. + +But there's a +possible resolution + +which comes out +of String theory, + +and in particular +from this idea, which + +is called the landscape +of String theory. + +Most String theorists believe +that String theory has + +no unique vacuum, +but instead, there's + +a colossal number, perhaps +something like 10 to the 500, + +different metastable +states, which + +even though they are metastable, +are incredibly long-lived, + +long-lived compared to the age +of the universe as we know it. + +So any one of these 10 to +the 500 different states + +could serve as effectively +the vacuum for one + +of these pocket universes. + +And the different +pocket universes + +would presumably fill the +whole set of possible vacua + +in the landscape, giving reality +to all these possibilities + +that come about +in String theory. + +And in particular, each +different type of vacuum + +would have its own +vacuum energy density. + +And because there are +both positive and negative + +contributions-- I think I +didn't read that out loud-- + +but there are both positive +and negative contributions + +that arise in quantum +field theories. + +So the vacuum energy +of a typical state + +could be either +positive or negative. + +And what we would +expect of these 10 + +to the 500 different +vacua is that they + +would have a range +of energy densities + +that would range from something +like minus 10 to the 120 + +to plus 10 to the 120 +times the observed value. + +So the observed value +would be in there, + +but would be an incredibly +small fraction of the universes. + +Yes? + +AUDIENCE: Does this mean that +so many pocket universes could + +be closed and opened as well +in terms of their geometry? + +Or-- + +PROFESSOR: They're +actually predicted + +to be open due to complications +about how they form, + +which I'm not going to go into. + +But they should all be open, but +very close to flat for the ones + +that under a lot of inflation. + +So they'd be +indistinguishable from flat, + +but technically, they'd be open. + +Yes? + +AUDIENCE: Is the minus 10 to +the 120 plus 10 to the 120 just + +chosen because we're off +520 orders of magnitude, + +or is it predicted +somewhere else? + +PROFESSOR: Well, +when we say we're off + +by 120 orders of magnitude, +the more precise statement + +is that the estimate of what +a typical range of the energy + +should be is 10 to 120 +times the observed value. + +So this is basically just +a restatement of that. + +And you might +wonder why I didn't + +put 5 times 10 to the +120, but in fact, the 120 + +itself is only accurate +to within a few orders + +of magnitude, so 5 +times that wouldn't + +have made any difference +in the way one + +actually interprets +those numbers. + +10 to the 123 is probably +slightly more accurate number + +actually. + +But this is good enough +for our purposes. + +Yes? + +AUDIENCE: Just a +general question + +about inflation properties. + +We think of attractive +gravity as driving + +the motion of objects +through space. + +So why do we think +of repulsive gravity + +like to drive the +expanse of space itself? + +PROFESSOR: Well, for one +thing, it does actually + +behave differently. + +Repulsive gravity, +repulsive gravity + +that appears in +general relativity, + +is not just ordinary gravity +with the opposite sign. + +Ordinary gravity +has the property + +that if I have two objects to +attract each other with a force + +proportional to the +masses of those objects. + +This repulsive +gravity is actually + +an effect caused by the negative +pressure in the space between. + +So if I have two +objects, they will + +start to accelerate apart +by the amount that's + +totally independent +of the masses. + +This is not really the +masses that's causing it. + +So the whole force was +completely different, + +so we can't really +just compare them. + +In either case, when +everything is moving apart, + +it's really a +matter of viewpoint + +when you think of the +whole space as expanding + +or whether you think +of the particles + +as moving through space. + +In relativity, there's no +way to put a needle on space, + +put a pen in it and +say this is stationary. + +So we really can't say that +the space is moving or not. + +In cosmology, we usually +find that the simpler picture + +and the one that we +will generally use + +is that space expands +with the matter. + +It gives a much +simpler description + +of how things behave. + +Good question. + +Yes? + +AUDIENCE: I have a question +going back a few slides. + +PROFESSOR: Sure, you +want me to go back. + +AUDIENCE: How the energy +of the early universe + +seemed to be close to zero. + +Are there theoretical +models that would explain + +or that would say it +should be exactly 0? + +PROFESSOR: Yeah, there are. + +I didn't mention it. + +But if the universe is closed, +which is a possibility. + +Even if it's very nearly flat, +it could still be closed. + +If it were closed, it would +have exactly zero energy. + +Yes? + +AUDIENCE: So the +cosmic background, + +microwave background, +picks ups that it's + +pretty similar in all +directions once correct for it. + +And this leads to the thought +that the cosmological principle + +all over the universe +is pretty identical. + +Is it possible that +we are actually + +located in just a smaller +like circular pathway + +and it may be different +than [? allowed. ?] + +And there's many +of these patches, + +so we-- there's actually +like a speckled form. + +PROFESSOR: OK. + +So if you didn't +hear the question, + +I was asked if it's possible +that the universe is not + +really homogeneous on +a very large scales, + +but really speckled, just +that speckles are large + +and our speckle might +look very different + +from other speckles +that are far away. + +And that was the question. + +And the answer is certainly +if the multiverse picture + +is right. + +That is exactly the case +that's being predicted. + +These other pocket +universes could + +be viewed as other +speckles in your language, + +and they'd be very different +from what we've observed. + +So inflation actually +changes one's attitude + +about this particular question. + +Back in the old days, +before inflation, + +the uniformity of the +universe had no explanation, + +so it became a postulate. + +And nobody postulates +that something + +is uniform on that scale. + +If you are going to +make a postulate, + +you just postulate that +the universe is uniform. + +So that was the postulate +that was in use. + +But now that we think of the +homogeneity of the universe + +as being generated by a +dynamical process, inflation, + +then, it's a natural +question to ask, + +what is the scale +of the homogeneity + +that that generates. + +And it's certainly +a scale that's + +much larger than +what we can observe. + +So we don't really expect +to see inhomogeneity + +as caused by different +pockets of inflation, + +but the model seems to +make it very plausible that + +is what we would see if +we could see far enough. + +Any other questions while +we're on a little break here? + +Yes? + +AUDIENCE: If the +universe is expanding, + +then I think like we are +expanding as well, so how can + +we observe the change +from a distance, + +in particular everything +is increasing scale? + +PROFESSOR: OK. + +That's a very good question. + +The question was if the +universe is expanding, + +then the universe is everything. + +So everything is expanding. + +And if everything's expanding, +when you compare things + +with rulers, they +have the same length. + +So how would you even observe +that everything was expanding? + +And the answer to +that is that when + +we say the universe +is expanding, + +we're not really saying that +everything is expanding. + +When we say the +universe is expanding, + +we really are saying that the +galaxies are getting further + +apart from each other, +but individual atoms + +are not getting bigger. + +The length of a +ruler, determined + +by the number of atoms +and how those atoms move + +to ground state, does not +expand with the universe. + +So the expansion is +now partially driven + +by the repulsive +gravity that exists + +now, which is causing the +universe to accelerate. + +But most of the expansion is +really just a residual velocity + +from the Big Bang, +whatever caused it then. + +I would assert inflation. + +And it's just a matter +of coasting outward, not + +being pulled outward, +and that coasting outward + +does not cause +atoms to get bigger. + +Yes? + +AUDIENCE: Is the current +idea that the expansion, + +like the acceleration, +is indefinite or are we + +going to reach a stop point? + +PROFESSOR: OK. + +What will be the ultimate +future, I'm being asked here. + +And the answer, as you might +guess, is nobody really knows. + +But in the context of the kind +of models I'm talking about, + +there is a pretty +definite answer, + +which is that our +pocket universe-- + +I'll answer at the level +of our pocket universe + +and I'll answer at the level +of the multiverse as a hole. + +At the level of our +pocket universe, + +our pocket universe +will thin out. + +Life will eventually +become impossible + +because matter density +will be too low. + +It will probably decay. + +Our vacuum is probably +not absolutely stable. + +Very few things 2 +String theory are, + +if something like String +theory is the right theory. + +But even though it +will be decaying, + +it will be expanding still +faster than it decays. + +So the decay will cause +holes in our universe. + +It will become +like Swiss cheese. + +But the universe, as +a whole, will just + +go on exponentially +expanding, perhaps + +forever, as far as +we can tell, forever. + +The multiverse is a +more vibrant object. + +The multiverse, +as I always said, + +would continue to generate +new pocket universes forever. + +So the multiverse +would forever be alive + +even though each pocket +universe in the multiverse + +would form at some time +and then ultimately die, + +die of thinning out +into nothingness. + +Yes? + +AUDIENCE: Just to add to that. + +Do you believe that maybe +it's a cyclic process? + +So it expand and decay and +then come back [? yet again ?] + +and then happen all over again? + +PROFESSOR: OK. + +The question is could it +be a cyclic process that + +expands, reaches maximum, +comes back and crunches, + +and expands again. + +That is certainly a +possibility, and there + +is some people who +take it very seriously. + +I don't see any evidence for it. + +And furthermore, there +never really was and still + +really isn't a reasonable +theory of the bounce + +that would have to be +a part of that theory. + +Yeah? + +AUDIENCE: But would it be +the expansion overtaking + +the decay in our own vacuum +that our universe exists + +in, our own little pocket +vacuums of ultimate decay + +within our system create more +little pocket universes-- + +[INTERPOSING VOICES] + +PROFESSOR: Within. + +Yes. + +Yeah, that's correct. + +They would not be a big fraction +of the volume of our universe, + +but, yes. + +The pieces in our universe +that might decay in the future + +would produce new +pocket universes. + +Most of them would be very low +energy pocket universes that + +would presumably not create +life, but some of them + +could nonetheless have a high +enough energy to create life. + +So we would expect +new, thriving universes + +to appear out of our +own pocket universe + +as it reaches this +expansion death. + +Yes? + +AUDIENCE: What does +distinguishes different vacua + +besides the +cosmological constant? + +PROFESSOR: The question +is what distinguishes + +the different vacua besides +the cosmological constant. + +And the answer is that they can +distinguish in many, many ways. + +What fundamentally +distinguishes them + +is the rearrangement +of the innards + +within the space, maybe a little +bit more precise without trying + +to get into details +which I probably + +don't understand either. + +But what's going on is that +String theory fundamentally + +says that space has nine +dimensions, not the three + +that we observe. + +And the way the +nine becomes three + +is that the extra +dimensions get twisted up + +into tiny little knots, so +they occupy too small a length + +to ever be seen. + +But there are many +different ways + +of twisting up those +extra dimensions, + +and that's really what leads +to these very large numbers + +of possible vacua. + +The extra dimensions are +twisted up differently. + +So that means that as +far as the low energy + +physics in these +different vacua-- + +practically everything +could be different, + +even the dimension of +space could be different. + +You could have different numbers +of dimensions compactified. + +And the whole particle +spectrum would + +be different because what we +view as a particle is really + +just the fluctuation of vacuum. + +And if you have a different +structure to the vacuum itself, + +the kinds of particles +that exist in it + +could be totally different. + +So the physics inside +these pocket universe + +could look tremendously +different from what + +we observe even though +that we're predicating + +the whole description +on the idea + +that, ultimately, it's +the same laws of physics + +that apply everywhere. + +Other questions? + +Yes? + +AUDIENCE: [INAUDIBLE]? + +PROFESSOR: OK. + +I think you're asking about +if we have a small patch, then + +that goes inflation and the rest +doesn't, how does the patch end + +up dominating because +it started out + +with just a small +fraction of the particles. + +Doesn't it still have the same +small fraction of particles? + +Is that what you're asking? + +AUDIENCE: Well, I guess. + +If you start out with the +smooth particles being + +the excessive matter, +and one of the particles + +behaves and the other +two particles [INAUDIBLE] + +even if it's still +just two particles? + +PROFESSOR: Right. + +It isn't the number of +particles conserved, basically, + +as all this happens, is I +think what you're asking. + +AUDIENCE: Well, even if it +eventually [? is called ?] + +expanded wave because the +second part will [INAUDIBLE] + +PROFESSOR: Well, let's see. + +I'm having a little +trouble hearing you. + +But let me make a definite-- +let me make a broader statement, + +and you can tell +me if I've answered + +what you're asking about or not. + +When one of these +patches undergoes + +the exponential +expansion of inflation, + +the energy is really +not very well described + +as particles at all. + +It's really described +in terms of fields. + +And fields sometimes behave +like particles, but not always. + +And in this case-- in principle, +there's a particle description + +too, but it's not +nearly as obvious + +as the field description. + +So you have energy stored in +fields and the region grows. + +The energy stored +in those fields + +actually increases +as the region goes. + +The energy density remains +approximately constant. + +And that sounds like +it would violate + +the conservation of energy, +but we discussed the fact + +that what saves +conservation of energy + +and allows this to happen in +spite of conservation of energy + +is that as the +region expands, it + +is filled by a gravitational +field, which is now occupying + +a larger and larger volume, and +that gravitational field has + +a negative energy density. + +So the total energy, which +is what has to be conserved, + +remains very small +and perhaps zero, + +and the region can +grow without limit + +while still having this very +small or zero total energy. + +Then, eventually it +decays and when it decays, + +it produces new particles, +and the colossal number + +of new particles, and +those would be the stuff + +that we would be made out of. + +And that number is vastly larger +than the number of particles + +that may have been +in this region + +when the inflation started. + +Yes? + +AUDIENCE: So does the emergence +of [INAUDIBLE] just purely + +a conservation of energy? + +Like, what do you need to +make these [? an organism ?], + +the negative energy, +zero [INAUDIBLE] I guess. + +PROFESSOR: Are you saying +the conservation of energy + +maybe controls the whole +show, and that this is really + +the only thing consistent +with conservation of energy? + +I think that's probably +an exaggeration + +because if nothing happened, +that would conserve energy too. + +So I think one needs more than +just the conservation of energy + +to be able to describe how the +universe is going to evolve. + +OK. + +Let me continue. + +Get back to the beginning +there, back to the end. + +OK. + +So I just finished talking about +the landscape of String theory + +and how it offers all +these possible vacua. + +So in particular, and this is +now the new stuff, if there + +are 10 to the 500 vacua of +String theory, for example. + +We don't really know the number, +but something crazy like that. + +And if only one part in +10 to the 120 of them + +have this very small energy, +thus the energy densities + +are spread from plus +10 to the 120 times + +what we observe to minus 10 to +the 120 times what we observe. + +That would mean that +what we observed + +would be a narrow slice in the +middle there occupying about 10 + +to the minus 120th of the +length of that spread. + +We would then expect-- +and all this, of course, + +is very crude estimates. + +It's not really the +numbers that's important, + +it's whether or not +you believe the ideas. + +But we'd expect then that +about 10 to the minus 120 + +of the different vacua would +have an acceptably low vacuum + +energy density. + +But that's still a +colossal number because 10 + +to the minus 120 +times 10 to the 500-- + +you add the exponents-- +is 10 to the 380. + +So we would still predict +that even though they'd + +be very rare, there might be +10 to the 380 different kinds + +of vacua, all which would +have a vacuum energy density + +as well as what we observe. + +So there's no problem finding, +in the landscape, vacua + +whose energy density is +as low as what we observe. + +But then there's the question +if they're so incredibly rare, + +wouldn't it take +a miracle for us + +to be living in one of these +incredibly unusual vacua + +with such an extraordinarily +low vacuum energy density. + +That then leads to +what is sometimes + +called Anthropic considerations +or perhaps a selection effect. + +And to see how that works and +make it sound not as crazy + +as it might sound +otherwise, I want + +to begin by giving an example +where I think one could really + +say that this effect happens. + +And that is suppose we just +look at our own position + +in our own visible +universe and look at, + +for example, the mass density. + +Where we're actually +living is incredibly + +unusual in many ways, but one +of the ways we could talk about, + +which is just simple +and quantitative, + +is the mass density. + +The mass density of the +things around this room + +is on the order of one gram per +centimeter cubed give or take + +a factor of 10. + +The factor of 10 is +not very important + +for I'm talking about here. + +The point is that +the average mass + +density of the universe, the +visible universe, is about 10 + +to the minus 30 grams +per centimeter cubed. + +It's really unbelievable +how empty the universe is. + +It's actually a far lower mass +density than is possible for us + +to achieve in laboratories +on Earth with the best vacua + +that we can make in +our laboratories. + +So where we're living +has a mass density of 10 + +to the 30 times the average +of the visible universe. + +So we're not living in a typical +place in our visible universe. + +We're living in an +extraordinarily atypical place + +within our visible universe. + +And we can ask how +would we explain that. + +Is it just a matter +of chance that we're + +living in a place that's +such a high mass density? + +Doesn't seem very likely +if it's a matter of chance. + +Is it luck? + +Is it divine +providence, whatever? + +I think most of us would admit +that it's probably a selection + +effect. + +That that's where life happens. + +Life doesn't happen throughout +most of the visible universe, + +but in these rare +places, like the surface + +of our planet, which is +special in more ways than just + +the mass density, but +the mass density alone + +is enough to make it +extraordinarily special. + +We're off by a factor +of 10 to the 30 + +from the average +of our environment. + +So if we're willing +to explain why + +we live in such an unusual place +within our visible universe + +and explain that as simply +a requirement for life, + +then it doesn't seem to be such +a stretch to maybe imagine-- + +and it was Steve Weinberg who +first emphasized this in 1987. + +Certainly not the +first person to say it, + +but the first person to +say it and have people + +sometimes believe him. + +He pointed out that may be the +low energy-- the low vacuum + +energy density could be +explained the same way. + +If we're not living +in a typical place + +within our visible +universe, there's + +no reason for similar +ideas to expect + +that we should be living +in a typical place + +in the multiverse. + +Maybe only a small fraction +of these different types + +of pocket universe's +can support life. + +And maybe the only +way to have life + +is to have a very small value +for the vacuum energy density. + +And there is some +physics behind that. + +Remember this vacuum energy +density drives expansion-- + +acceleration, I should say. + +So if the vacuum energy density +were significantly larger + +than what we +observe, the universe + +would accelerate +incredibly rapidly + +and would fly apart +before there'd + +be any time for anything +interesting to happen + +like galaxies forming. + +Weinberg based his arguments +here on the assumption + +that galaxies are a +necessity for life. + +Yes? + +AUDIENCE: So that's +what I was going to ask. + +Why do we assume that our +universe is the only one that + +could have like-- why couldn't +just all the multi-universes + +have like-- + +PROFESSOR: Right. + +Right. + +Well, that's OK. + +That is what I am talking about. + +I'm trying to answer it. + +So if the vacuum energy density +were significantly larger + +than what we observe, +the universes + +would fly apart so fast +that there could never + +be galaxies and therefore +never planets, none of things + +that we think of as being +associated with life as we know + +it. + +Conversely, if the vacuum energy +density were negative, but had + +a magnitude large compared +to what we observed, + +that would be a large negative +acceleration, an implosion. + +And those universes would +just implode, collapse, + +in an incredibly short amount +of time, much too fast for life, + +of any type that we +know of, to form. + +So there is a physical argument +which suggests that life only + +forms when the vacuum +energy density is very low. + +And Weinberg and his +collaborators-- and this + +is the same Steve Weinberg who +wrote the First Three Minutes + +that we're reading-- calculated +what the requirements would + +be for galaxy formation. + +And they decided that, within +about a factor of 5 or so, + +the vacuum energy +density would have + +to be about the same as +what we observe or less + +in order for galaxies to form. + +So it seems like a +possible explanation. + +It's certainly not a generally +accepted explanation. + +These things are very +controversial one. + +I guess that's, in +fact, what I was + +going to talk about +on my next slide. + +Some physicists by this +selection effect idea. + +I tend to buy it. + +But a number of physicists +regard it as totally + +ridiculous, saying you +could explain anything + +if you except +arguments like that. + +And there's some truth to that. + +You can explain a lot +of things if you're + +willing to just say, +well, maybe that's needed + +for life to happen. + +So because of that, I would +say that these selection effect + +arguments or anthropic +arguments should always + +be viewed as the +arguments of last resort. + +That is, unless we +actually understand + +the landscape of +String theory, which + +we do not in detail, +and once we actually + +understand what it +takes to create life, + +we really can't do more than +give plausibility arguments + +to justify these +anthropic explanations. + +But these anthropic +arguments do sound sensible. + +I think there's nothing +illogical about them, + +and they could very well be the +explanations for some things. + +As I pointed out, I think it +is the explanation for why + +we are living in +such an unusual place + +within our own visible universe. + +And it means that these +selection effect arguments + +become very attractive when the +search for more deterministic + +explanations have failed. + +And in the case of trying to +explain the very small vacuum + +energy density, I think +other attempts have failed. + +We don't have any calculational, +deterministic understanding + +for why the vacuum energy +should be so small. + +So is it time to accept this +explanation of last resort + +that the vacuum energy +density is small + +because it has to be +for life to the evolve? + +Your guess is as good as mine. + +I don't really know. + +But I would say that, in the +case of the vacuum energy + +density, people have +been trying very, very + +hard for quite a +few years now to try + +to find a particle physics +explanation for why the vacuum + +energy has to be small, and +nobody's really found anything + +that anybody has found-- that +any large number of people + +have found to be acceptable. + +So it is certainly a +very serious problem. + +And I think it is +time to take seriously + +the argument of last resort, +that maybe it's that way only + +because in the parts of the +multiverse where it's not + +that way, nobody lives there. + +So I would say it's +hard to deny, as of now, + +that the selection +effect explanation is + +the most plausible of +any explanation that + +is known at the present time. + +To summarize things-- +I'm actually done now, + +but let me just +summarize what I said + +to remind you where we're at. + +I've argued that the +inflationary paradigm + +is in great shape. + +It explains the large +scale uniformity. + +It predicts the mass +density of the universe + +to better than about 1% accuracy +and explains the ripples + +that we see in the cosmic +background radiation, + +explaining them as a result +of quantum fluctuations + +that took place in the +very early universe. + +The picture leads +to three ideas that + +at least point towards +the idea of a multiverse. + +It certainly doesn't prove that +we're living in a multiverse. + +But the three ideas that +point in that direction + +are, first of all, the +statement that almost + +all inflationary models +lead to this feature + +of eternal inflation, that +the exponential expansion + +of the inflating material, +generally speaking, + +out runs the decay +of that material + +so that the volume grows +exponentially forever. + +Second point is that, in 1998, +the astronomers discovered + +this rather amazing fact +that the universe is not + +slowing down as it expands, +but in fact, is accelerating. + +And that indicates +that there has + +to be some peculiar material +in the universe other than what + +we already knew was here, +and that peculiar material is + +called the dark energy. + +And we don't have any simple +interpretation of what it is, + +but it seems to most +likely be vacuum energy. + +And if it is, it +leads immediately + +to the important +question of can we + +understand why it has +a value that it has. + +It seems to be much smaller +than what we would expect. + +And then three, the +String theorists + +give us an interesting +way out here. + +The String theorists tell +us that maybe there's + +not unique vacuum to +the laws of physics, + +but maybe there's a +huge number, which + +seems to be in fact what +String theory predicts. + +And if there is, then of +the many different vacua + +you expect there to be, +in fact perhaps even + +a large number, that would have +this very small vacuum energy + +density, a tiny fraction of +the total different vacua, + +but nonetheless a +large number of vacua + +that would have this property. + +And then this +selection effect idea + +can provide a +possible explanation + +for why we are living in one of +those very unusual vacua which + +has this incredibly tiny +vacuum energy density. + +So finally, I'd +just like to close + +with a little sociological +discussion here. + +Do physicists really +take this seriously? + +And I'd like to tell you about +a conversation that took place + +at a conference a few years ago. + +Starting with Martin Rees, who I +don't know if you know the name + +or not, but he's an Astronomer +Royal of Great Britain, + +former president +of Royal Society, + +former master of +Trinity College as well, + +a very distinguished person, +nice guy, too, by the way. + +And he said that +he is sufficiently + +confident in the multiverse +to bet his dog's life on it. + +Andrei Linde, from Stanford, +a real enthusiastic person + +about the multiverse, one of the +founders of inflation as well, + +said that he's so +confident that he + +would bet his own life on it. + +Steve Weinberg was not +at this conference, + +but he wrote an article +commenting on this discussion + +later which became known. + +And I always considered +Steve Weinberg + +the voice of reason, +which is why we're + +reading the First Three Minutes. + +And he said that I have +just enough confidence + +in the multiverse to +bet-- guess what's + +coming-- the lives of both +Andrei Linde and Martin Rees' + +dog. + +That's it for the +summary, or the overview. + +Anymore overview type +questions before we get back + +to the beginning, actual +beginning of the class? + +Yes? + +AUDIENCE: You said-- so +selection effect argument says + +that it's because life +exists within these certain + +constraints, omega being one +and low energy larger than it + +generally is allowed, that +life could exist in this way. + +But we're considering +carbon-based life. + +What if there's some +other [INAUDIBLE] life + +forms out there that gives +us different energies + +and radiation and +stuff like that? + +PROFESSOR: Yeah, what +you're pointing toward + +is certainly a severe weakness +of these selection effect + +arguments, that we really know +about carbon-based life, life + +that's like us, and we can +talk about what conditions + +are needed to make life +like us, but maybe there's + +life that's totally +different from us + +that we don't know +anything about that + +might be able to +live under totally + +different circumstances. + +That is a real weakness. + +However, I would argue-- and +this is also controversial. + +Not everybody would agree +with what I'm about to say. + +But I would argue that if +we're willing to explain + +the unusual features of +the piece of the universe + +that we live in by +selection effect arguments-- + +the fact I used, the +example is simply + +that we're living a place +where the mass density is + +10 to the 30 times +larger than the mean. + +If we're willing to use the +anthropic arguments to explain + +that, then I think all those +same issues arise there also. + +If life was really teem-- +if the universe was really + +teeming with a different +kind of life that + +thrived in vacua, +then we'd be much more + +likely to be one of them, +extremely unusual creatures + +living on the +surfaces of planets. + +So I think it's a +possible weakness + +that one has to +keep in mind, but I + +don't think it should +stop us from using + +those arguments completely. + +But it is certainly a +cause for skepticism. + +Yes? + +AUDIENCE: Isn't the point +of the selection principle + +just the fact that exist-- +the universe selected for us. + +Does it matter for the general +of just for like carbon-based + +[? organisms? ?] Is the fact +that we exist [INAUDIBLE] + +that we've been selected +for [INAUDIBLE]? + +PROFESSOR: You're +asking about, I + +think, how peculiar +to carbon-based life + +should we expect these selection +effect arguments to be. + +AUDIENCE: Doesn't the selection +affect where [INAUDIBLE]? + +PROFESSOR: Now that's +an important point, + +and certainly one that's not +settled among philosophers, + +probabilist, +physicists, or anybody. + +What you're asking-- if +I'm summarizing it right-- + +is when we're thinking +of the selection effects, + +should we may be only talk +about carbon-based life + +because, after all, we know +that we are carbon-based life. + +So what does it matter if +there's other kinds of life + +out there? + +That's one way of +looking at it, certainly. + +Or, maybe we should think +about all kinds of life. + +That's something +else that people say. + +The problem I would-- +I tend to be by the way + +the kind of person that thinks +that all life is relevant, + +not just carbon-based life. + +Because we happen +to be carbon-based, + +and we happen to +have fingernails + +that have a certain +length, and we + +happen to have hair +that's a certain length + +or a certain +thickness, does that + +mean we should only +think of those things + +as being relevant +when we're thinking + +about selection effects? + +And I would say +that they're not. + +If our hair had a +different thicknesses, + +we would still be able to +make measurements and so on. + +So from my point +of view, when one + +thinks about these issues +of selection effects, + +one should precondition +only on the elements that + +are necessary to ask the +question in the first place. + +And what I would like to +think-- and as I point out, + +this is controversial, +not everybody + +agrees with me-- is that +a good theory should + +be a theory in which you could +say that most of the people who + +ask this particular question +will get the answer that we + +say. + +If only a tiny fraction of +people who ask that question + +will get that answer, but +that same tiny fraction + +happens to have hair +of a certain color + +and you have hair +of that color, to me + +that's still not an explanation +because you don't know why you + +have hair of that +color or why you're + +living in such an unusual place. + +OK that strikes up a +lot of conversations. + +Yes? + +AUDIENCE: You +mentioned last time + +that the different +pocket universes + +that comprise the multiverse +are disconnected from each other + +though they start out as patches +within the preceding vacua. + +What starts to disconnect +them fundamentally + +from the vacuum +which they formed? + +PROFESSOR: The question is +what is it that separates these + +different pocket universe's. + +If they start out all +in the same space, + +don't they remain all +in the same space? + +And the answer is they do, but +the space they started out in + +was expanding at +a very rapid rate. + +So in most cases, +but not all actually, + +two pocket universes will +form far enough apart + +from each other +that they will never + +touch each other as they grow +because the space in between + +will expand to fast to +ever allow them to meet. + +However, collisions +of pocket universities + +will occur if two pocket +universes form close enough + +to each other, the expansion +of space in between + +will not be enough to keep them +apart, and they will glide. + +How frequent one should +think of that as being + +is an incredibly tough +question to which + +nobody knows the answer. + +There are actually-- +at least there + +is at least one +astronomical paper + +in the literature by +a group of astronomers + +who have looked for possible +signs of a collision of bubbles + +in our past. + +They did not find +anything definitive. + +But it is something +to think about, + +and it's something people +are thinking about. + +There really are +quite a few papers + +about collisions of +bubbles in the literature. + +Yes? + +AUDIENCE: How long +is long-lived? + +So if the energy density was +too large and too negative + +would that still +be long-lived if it + +were to collide upon itself? + +PROFESSOR: Talking about the +lifetime of these universes + +that I said would +collapse very quickly. + +How quickly do I mean? + +AUDIENCE: Like the +metastable long-lived. + +PROFESSOR: I used +the word long-lived + +at least twice in what I've +talked about-- I talked + +about the long-lived +metastable vacua. + +And there, by long-lived +I mean anything + +that's long compared to the age +of our universe since the Big + +Bang. + +Long means long +compared to 10 to the 10 + +years in that context. + +I also said that if the +vacuum energy of a universe + +were large and negative, it +would very rapidly collapse. + +That could be as fast as +10 to the minus 20 seconds. + +It could be very fast +depending on how large + +the cosmological constant was. + +Yes? + +AUDIENCE: So I have read +that there's an effect such + +that if you're vacuum +can be seen differently + +by different observers. + +For example, inertial-- +there's something + +that I read in effect it says +that if one inertial observer + +sees vacuum, another +observer that's + +accelerating with +respect to that observer + +would see like a number +of particles [INAUDIBLE] + +a warm gas. + +So how much of the effect we +observe are due to the fact + +that perhaps we believe the +universe is accelerating, + +and we're accelerating perhaps +with respect to some vacuum + +and we're just observing that. + +That's just a fact of our +motion not necessarily the-- + +PROFESSOR: You're +touching on something + +that is in fact very confusing. + +What is your name? + +AUDIENCE: Hani. + +PROFESSOR: Hani? + +What Hani said was +that he had heard-- + +and this is correct-- +that if one had simply + +a region of ordinary +vacuum-- and I am now + +going to talk about +special [INAUDIBLE] vacuum. + +You don't even need relativity. + +You don't general relativity, +you just need this. + +If you had an accelerating +observer moving + +through that vacuum, the +accelerating observer + +would not see something +that looked like vacuum, + +but rather would see particles +that in fact would look + +like they had a finite +temperature which you can + +calculate, a temperature that's +determined by the acceleration. + +So the question is, +how much of what + +we see should we think +of as really being there + +and how much might be caused +just by our own motion. + +And there's not a terribly +great answer to that question + +that I know of except that we-- +when these questions come up, + +we tend to just +adopt the philosophy + +that an observer +who's freely moving, + +which really means moving +with the gravitational field, + +a geodesic observer as the +word phrase is sometimes used, + +essentially defines what +you might call reality + +and then if you calculate what +accelerating observers might + +see in terms of that reality. + +And we are almost +geodesic observers. + +The Earth is exerting a +force on our feet, which + +violates that a little bit, +but by the overall cosmic scale + +of things where +the speed of light + +is what determines +what's significant, + +we are essentially inertial +or geodesic observers. + +Yes, Aviv? + +Aviv first and then +the one in front. + +AUDIENCE: So I'm wondering +about the philosophical approach + +to this discussion and why +the very-- by the definition, + +we can't possibly +observe another universe. + +And so maybe we +have a theory that + +makes a lot of great +predictions like inflation. + +But it may also make +predictions about multiverse. + +We can't possibly empirically +determine whether that's true + +or not, so a +nonfalsifiable question. + +And so I feel like +[INAUDIBLE] who [INAUDIBLE] + +essentially never +going to be answered. + +And if we're going to +be strict empiricists, + +should we not be concerned +with this question? + +PROFESSOR: The question is if we +could never see another pocket + +universe, is it even +a valid question + +to discuss whether +or not they exist, + +a valid scientific question. + +That is also a question +which is generally + +debated in the community, and +people have taken both sides. + +There certainly is +a point of view, + +which I think I +tend to take, which + +is that we never really +insist that every aspect + +of our theories can be tested. + +If you think about any theory, +even Newtonian gravity, + +you can certainly +imagine implications + +of Newtonian +gravity that you can + +calculate that +nobody's ever measured. + +So I think in practice we +tend to accept theories + +when they have made enough +measurements that we've tested + +so that the theory +becomes persuasive. + +And when that happens, I think +we should, at the same time, + +take seriously whatever +those words mean, + +the implications that the theory +has for things that cannot be + +directly tested. + +As far as the other +pocket universes, + +some people think +it's important, + +and maybe I do too, +that even though it's + +highly unlikely, incredibly +unlikely, unbelievably unlikely + +that we'll ever acquire +direct observational evidence + +for another pocket universe, +it's not really in principle + +impossible because of the fact +that pocket universes can, + +in principle, collide. + +So we could, in principle, +describe with evidence + +that our universe has had +contact with another pocket + +universe in the past. + +Yes. + +AUDIENCE: What +determines the stability + +of a particular vacuum state? + +Is it simply things with higher +vacuum energies are less stable + +and things with lower vacuum +energies are more stable? + +PROFESSOR: The question +is what determines + +the stability of +the different vacua. + +Is it simply that +higher energy ones + +are more unstable and lower +energy ones are more stable + +or is it more +complicated than that? + +And the answer, +as far as I know, + +is that there is a trend +for higher energy ones + +to be more unstable and lower +energy ones to be more stable. + +But it's not as simple as that. + +There are also wide +variations that + +are independent of +the energy density. + +AUDIENCE: If the one +that we're living in + +is incredibly is really +ridiculously close to zero + +in a city that seems to make +it incredibly unlikely that we + +would pay anything else I soon + +PROFESSOR: Right. + +The question is if +our universe has + +such has such a +small energy density + +relative to the average. + +Wouldn't that mean +that we should also + +expect to be much more +long-lived than average? + +And the answer is I guess so. + +But as far as the effect +on the Swiss cheese + +picture that I described +for the ultimate future, + +it doesn't change the +words that I used. + +It just changes how frequent +those decays would be. + +But since the future of +this pocket universe, + +if this picture is +right, will be infinite, + +decays will happen no matter +how small the probability is. + +An infinite number of +decays will happen in fact. + +OK we should probably +go on now even + +if there are more questions. + +We have a whole term to +discuss things like this. + +The next thing I +want to do is handle + +some housekeeping details. + +I'd like to arrange +office hours. + +And the problem sets +are due on Friday, + +so what [? Tsingtao ?] +and I thought + +was that a good time +for office hours + +would be on Wednesdays +and Thursdays. + +One of us on each of those days. + +It turns out that I can't +really do Thursdays, + +so one of us on +each of those days + +ends up meaning +that I'll probably + +be having office +hours on Wednesdays. + +This is all +provisional depending + +on how it works with you folks. + +And [? Tsingtao ?] +will probably be + +having office +hours on Thursdays. + +Generally speaking, if one +wants to have an office + +hour that most +people can come to, + +I think it should be +in the late afternoon. + +So maybe we'll start by +discussing my office hours + +since it comes before +[? Tsingtao's, ?] Wednesday + +versus Thursday. + +So on Wednesday, I +can do an office hour + +in the late, normal afternoon, +which might mean 4:00 to 5:00 + +I think after five some +people have sports activities + +and things. + +We're told to try to +avoid those hours. + +So 4:00 to 5:00 would be +a reasonable possibility + +for my office hour on Wednesday. + +If that doesn't +work, I could stay + +and have the office +hour in the evening. + +That's actually what +I did two years ago. + +I had an office hour +from 7:30 to 8:30. + +It was also +Wednesdays-- I forget. + +But it was in the evening, +and that's a possibility. + +So let me ask if I have my +office hour from 4:00 to 5:00 + +on Wednesdays, how +many of you who + +might be interested in coming +would not be able to come? + +1, 2, 3, 4, 5, 6, +7, 8, 9, 10, 11, 12. + +A significant number, but +most of you can come at least. + +Let me ask the corresponding +question for the evening. + +Suppose I made the office +hour from 7:30 to 8:30 + +in the evening on Wednesdays. + +In that case, how many of +you who might want to come + +would not be able to come? + +1, 2, 3 5, 6, so it's a smaller +number, but not vastly smaller. + +OK I think I'll do it in +the evening for the benefit + +of the difference +between those two groups. + +And the evening also has +the little slight advantage + +that it can be a little more +open-ended if people still + +have questions after +the normal time is over. + +So I will make my office hour on +Wednesday's from 7:30 to 8:30. + +Is that particular hour as good +an hour as any on Wednesday + +evening. + +Would people want to +move it earlier or later? + +Any suggestions for moving +it earlier or later? + +AUDIENCE: I know people have +sports til technically at least + +7:00, but if it's 6:30 to +7:30 might be a little-- + +PROFESSOR: 6:30? + +You'll be starting at 6-- +starting at 6:30 versus-- 6:30 + +to 7:30, starting at 6:30. + +Well, I'd be happy +to do that, but I + +suspect we might run +into problems with people + +who have sport +activities, but let's see. + +How many of you would +be inconvenienced + +if I started at 6:30 +instead of 7:30? + +3, 4, 5, 6, a number. + +So I think we'll honor +that and start at 7:30. + +I assume 7 is also a bit of +a problem for those people. + +We'll say 7:30. + +Now, I have to announce +that this week is going + +to unfortunately have to be +an exception because I already + +have plans for Wednesday night. + +So for this week, I +think the best thing-- + +the only possible +thing, probably + +the best-- it's almost +the only possible thing + +would be 4:00 to +5:00 on Wednesday. + +Wednesday's bit tomorrow. + +I'll send you all an email +when I find a room for that. + +I think I'll probably +not have it in my office, + +but maybe it will +be in my office. + +Comment up there? + +AUDIENCE: Oh, I was just +going to ask where, but you-- + +PROFESSOR: Where? + +OK, I guess then the +fourth option's my office. + +I was hoping to put +a sign of my office + +if we're someplace +other than my office. + +So should put this +on the board too. + +Tomorrow 4:00 to 5:00 PM. + +So be at my office +or I'll send email. + +Yes? + +AUDIENCE: How will we be turning +in the Thursday problem set? + +PROFESSOR: We're going +to talk about that now. + +For Thursday, for +[? Tsingtao, ?] I remember + +you had some constraints. + +So what was possible? + +TSINGTAO: Yeah. + +So I usually leave +around 7:00 PM, + +so I have appointment +[? meeting ?], + +and today is probably +not very good at 4:00 PM. + +PROFESSOR: So 4:00 to 5:00 is a +possibility for [? Tsingtao ?] + +on Thursday, and I +guess later than that. + +But should be over by +5:00-- by 7:00 either + +or do you want it to +be over before then. + +TSINGTAO: Oh, 6:00 to 7:002 +Oh, 6:00 to 7:002 I guess. + +PROFESSOR: 6:00 to +7:00 would be OK? + +TSINGTAO: Yeah, that's OK. + +PROFESSOR: OK, so let's +start with 4:00 to 5:00. + +If [? Tsingtao ?] was to have +an office hour from 4:00 to 5:00 + +on Thursdays, how many of you +think you might want to go + +would be unable to? + +Wow, tons! + +OK, that seems more than +half of you I think. + +So I guess we try to avoid that. + +This impact's probably +an athletic region, + +but maybe we'll have to do that +for lack of an alternative. + +Suppose it were 5:00 to 6:00. + +How many of you who would be +interesting in coming-- who + +might be interesting +in coming, I should say + +I guess because it'll +vary from week to week-- + +but how many of you +who think you might + +be interested in +coming would not + +be able to come from 5:00 +to 6:00 on Thursdays. + +OK, a small group. + +1, 2, 3, 4, 5, 6, 7. + +Looks to me like 7. + +And let's say, I +said 4:00-- That + +was at 6:00-- that +was 5:00 to 6:00. + +So maybe we should next try 5:30 +to 6:30 in smaller increments + +here. + +If we're 5:30 to +6:30, how many of you + +would not be able to come? + +Looks like pretty +much the same people. + +And if it were 6:00 to +7:00, how many of you + +would not be able to come? + +Same people, I think it is +literally the same people. + +OK. + +So it looks like 4:00 +to 5:00 is very bad. + +And all other times +are about equivalent. + +So I think if all other +times are bad equivalently, + +we probably might as well +make it 5:00 to 6:00. + +And that way +[? Tsingtao ?] can get off + +to an earliest possible start +to wherever he's going at 7:00, + +and it also means a little +more flexibility in the end + +if there are more questions. + +AUDIENCE: Where is that located? + +PROFESSOR: That +also, I think, will + +require us to get a room +which will be announced. + +So I will try to +arrange rooms tomorrow + +morning and send +it by email, and I + +guess I'll post it on +the website as well. + +Any other organizational-- +and questions + +limited to organizational +questions now? + +Get back to physics later. + +Any organizational +questions before we + +start on Doppler shifts? + +Yes? + +AUDIENCE: If I can't make +a single office hour, + +how should I field questions +when I have questions? + +PROFESSOR: A good question. + +Yeah, there may be some +people, and apparently there is + +at least one who cannot +make either of these times, + +even though we tried +to optimize things. + +So by all means, +don't feel like you + +don't have a channel +for questions. + +If you have a question, +send an email to + +either me, or +[? Tsingtao, ?] or both. + +And we'll either answer +it together with you + +or answer you by email depending +on what the question is + +and what seems useful. + +And that goes for everybody. + +In that case, if +everybody's on board, + +we will now start the actual +material for the term. + +Well, the overview +is an overview + +of the material for the term, +but not at the standard pace + +and the standard +level of detail. + +So what I want to +talk about this week-- + +and I guess I'll only get +to start today and finish + +on Thursday-- I had +planned to tell you + +everything you need to know +for the problem set by today, + +but that's not going to happen. + +So I don't-- if people complain, +we could consider postponing + +the due date of the problem +set, so consider that an option. + +But probably you could +do the problem set anyway + +because it is all +described in lecture notes. + +But if any of you have +difficulties meeting + +that deadline, it will be a +somewhat flexible deadline + +this week because of +the fact that I'm not + +covering the material +today as I had planned. + +And I'll admit that's not +necessarily a good thing + +to do in terms of problem set. + +So we're going to begin +the course, in principle, + +by talking about Hubble's law, +although Hubble's law will + +rapidly lead us to the +question of the Doppler shift, + +which is what I'll +mainly be talking + +about for the rest of today +and for most of Thursday. + +Hubble's law itself +is a simple equation + +that v is equal to h r, +where v is the recession + +velocity of any typical galaxy. + +Hubble's law is +not an exact law, + +so individual galaxies will +deviate from Hubble's law. + +But in principle, +Hubble's law tells you + +what the recession velocity +is of a galaxy, at least + +to reasonable accuracy. + +Where h is what is often +called Hubble's constant. + +Sometimes, it is called +the Hubble parameter. + +I like actually-- it's called +the Hubble expansion rate. + +The problem with calling +Hubble's constant + +is that it's not +really a constant + +over the lifetime +of the universe. + +It's a constant over the +lifetime of an astronomer, + +but not a constant over the +lifetime of the universe? + +And we'll be talking about +universes, not astronomers, + +at least for the most part. + +And even over history, +it's not a constant + +because the estimate +of Hubble's constant + +has actually changed by a +factor of about 10 or so + +since Hubble's +original estimate. + +And the r that appears here +is the distance to the galaxy. + +And if you look at the lecture +notes from two years ago, + +they start out by saying +that Hubble's law was + +discovered by Hubble in 1929. + +When I looked at that +first sentence in my notes, + +and when I started to +revise them for this year, + +I realized that I heard +that that statement has + +become controversial. + +Almost everything in +cosmology is controversial, + +so even that statement +is controversial. + +There are claims +that Lemaitre really + +deserves credit for Hubble's +law rather than Hubble. + +And there's some +validity to that claim. + +There's also some +[? intrigued ?] that happens, + +if you want to read about this. + +It was discovered by +several of-- I think + +amateur historians I think is +what they are often referred + +to in the press-- that we know +mainly of Lemaitre's work-- we + +being the Western speaking, +the Western English speaking + +world-- know mainly +of a Lemaitre's work + +through a 1931 translation +in a 1927 paper + +he wrote about the +foundations of cosmology. + +And it turned out that several +significant seeming paragraphs + +in the 1927 French +article somehow + +didn't make it to the 1931 +English translation, paragraphs + +about the Hubble constant. + +And for a while, that +seemed like dirty play + +and there were accusations that +Hubble, or friends of Hubble, + +had suppressed those +paragraphs when + +the article was translated. + +The truth finally was +discovered a couple years ago + +by a physicist named Mario Livio +who actually was on the Daily + +Show a couple nights +ago by the way. + +He has a book out now, not about +this, but about other things. + +But anyway, he +discovered by going + +through the archives of the +monthly notices of astronomy, + +which is where the article +was published in English. + +And turned out it +was Lemaitre himself + +he removed those paragraphs. + +The paragraphs basically +gave a numerical estimate + +of the Hubble constant, but by +1931 Hubble's papered already + +been published, so Lemaitre +felt that it was only + +a less accurate estimate +of the same quantity + +that Hubble had estimated, so he +cut it out of his translation. + +What certainly is +true is that Lemaitre + +knew about Hubble's law +on theoretical grounds. + +Lemaitre was building a model +of an expanding universe. + +I don't know if he is +really the first person + +to know that an expanding +universe model gave rise + +to a linear relationship +between velocity and distance, + +but he certainly did know about +it and understood Hubble's law + +and give an estimate +of it based on data. + +What he did not +do, however, is try + +to use data to actually +show that there + +was a linear relationship. + +What Lemaitre did, +in those paragraphs + +that were not +translated, was simply + +to look at a large +group of galaxies, + +figure an average value for +v and an average value of r + +and determine h from +dividing those two averages. + +And he admitted +that there was not + +really good enough data to tell +if the relationship is linear + +or not. + +I think it is definitely +fair to say that Hubble + +is the person who deserves +credit for arguing first really + +with a fairly weak argument, +but then got stronger over time, + +that there really is +astronomical evidence + +for this linear relationship +between velocity and distance. + +So probably it will continue +to be called Hubble's law. + +If you look in +Wikipedia, it tells you + +either one is acceptable +at the moment, + +but Wikipedia articles +change rapidly, + +so we'll see what +it says next year. + +It's also mentioned +that we should probably + +root for Lemaitre since +Lemaitre, it turns out-- well, + +he was a Belgian priest, +it was often described, + +but he was also an MIT +student, had a Ph.D. for MIT, + +which he received in 1927. + +You can actually +read his thesis. + +When I was writing +my [INAUDIBLE] book, + +I remember going +to the MIT archives + +and actually picking up +his thesis and reading it. + +It's not that well-written +actually, but it's interesting. + +Although he got +his Ph.D. from MIT, + +it also turns out that +he did most of his work + +down Mass Ave at the +Harvard College Observatory, + +but the Harvard +College Observatory + +did not give degrees +in those days. + +It was just an observatory. + +So he wanted to get a +degree, so he signed up + +at MIT for the Ph.D. +Program and wrote a thesis, + +received a Ph.D. + +Onward, what I really +want to talk about + +is, after mentioning +Hubble's law-- + +so Hubble's law as an indication +that the universe is expanding. + +And we'll talk more about the +history of all this later, + +and it actually is very +well-described in Steve + +Weinberg's book. + +But initially, Einstein +proposed a model + +of the universe that was +static, and it was really + +Hubble who convinced +Einstein that observationally + +the universe does not appear +to be static, but does + +appear instead to obey +this expansion law. + +So that gave rise to the theory +of the expanding universe. + +But what I want to +talk about today + +is how one measures the +v that appears here. + +There's also a big +discussion about how + +one measures r, the distance. + +And that is, I think, rather +well-done in Steve Weinberg's + +book, and I'm going to +pretty much leave it + +to your reading of +Steve Weinberg's book + +to learn about how distances to +distant galaxies are estimated. + +Roughly-speaking, +I might just say + +that they are estimated +by finding objects + +in those distant galaxies +whose brightnesses you think + +you know, by one +means or another. + +And a complicated story +is what objects are there + +in brightnesses +we think we know. + +But once you find an +object whose brightness + +you think you know, those +go by the general name + +of standard candles, +a standard candle + +being an object whose +brightness you know, + +then you can tell +how far the object is + +by how bright it appears. + +And that becomes a very +straightforward way + +of estimating distances, +and that is the only way + +we really have of estimating +distances of distant galaxies. + +So it's a much longer story than +what I just said, and you'll + +read about it in +Weinberg's book. + +The velocity is measured +by the Doppler shift, + +and that's what lecture +notes one are mainly about, + +and that's what I'll be +talking about for the remaining + +few minutes of today's class. + +And what we want to do in the +course of this set of lecture + +notes, this week of +class I guess it will be, + +is understand how to +calculate the Doppler + +shift both non-relativistically +and relativistically, + +and we'll just work out the +primary cases of observer + +stationary source moving, source +stationary observer moving, + +and all in a line, for +both the relativistic and + +non-relativistic cases. + +So I think I'll launch into +the first calculation, which + +you might even have +time to finish. + +I'd like to consider +a case where + +the observer is stationary +and the source is moving, + +which is normally how we +think of the distant galaxies. + +We work in our own reference +frame, so we're stationary, + +the galaxy is moving. + +How do we calculate +this redshift + +I should say at the +asset here, however-- + +I don't know if I said +it in the lecture notes-- + +that the cosmological +redshift is actually + +a little bit different from what +we're calculating this week. + +This week, we're calculating +the special relativity redshift. + +But cosmology is not controlled +by special relativity + +because special relativity +does not describe gravity, + +and gravity plays a +major role in cosmology. + +So the cosmological redshift, +we will talk about a little + +later in the course, +in a more precise way. + +But for now, we, like Hubble-- +Hubble didn't know any better-- + +are ignoring gravity, which +is OK for the nearby stars, + +and the further away they +are, the more important + +these gravitational influences +are, and ignoring gravity one + +could just use special +relativity or even + +Newtonian kinematics +to calculate + +the relationship between +v and the redshift. + +And that's what we'll +be talking about. + +So the first problem that +we want to talk about-- + +and I guess I'll just set it up +and that's as far as we get-- + +will be a problem where there's +a source of radiation, which + +is moving to the right in our +diagram with a velocity, v, + +and an observer +who is stationary. + +Now of course, all these are +frame dependent statements, + +but we're working +in a frame where + +the observer is stationary. + +And we're also going to assume +for the non-relativistic case, + +that the air-- we'll be talking +about sound waves-- but the air + +is stationary in this frame. + +So the frame of backboard is not +only the frame of the observer, + +but it's also the +frame of the air + +when we're talking about the +non-relativistic sound wave + +calculation. + +So to define our +notation, we're going + +to let u be equal the +velocity of the sound wave. + +And that would normally be +measured relative to the air, + +but the air will be at +rest in this picture, + +so u will be the velocity +of the sound wave + +relative to the diagram. + +v is the velocity of the +source already shown. + +And we'll be interested +in two time periods, + +delta t sub s where +s stands for source, + +which will be the period of +the wave at the source, which + +is the same as talking +about the period of the wave + +as it would be +measured by the source. + +And delta t sub +O-- that's supposed + +to be a capital O, not a zero. + +It is the period of the wave +at the observer or as observed. + +And the important point, which +is maybe obvious qualitatively, + +is that these two times, +or time intervals, + +will not be equal to each other. + +And the reason, basically, +is that because the source is + +moving-- and I've defined +positive v the way + +astronomers would as moving away +from us-- because the source is + +moving away from us, +each successive wave that + +goes from the source to us has +to travel a little bit further. + +And that means that each wave +crest is slightly delayed + +from when it would +have gotten here + +if everything were stationary. + +And if you delay +each wave crest, + +it means the time +between crests is larger. + +And that means +that we expect here + +that delta t sub O will be +larger than delta t sub s + +because of this extra distance +that each wave crest has + +to travel. + +And what we'll be +doing next time-- + +I think I will just +leave the calculations + +for next time-- is +calculating that. + +And then doing the same +thing for the case where + +the observers moving and +the source is stationary, + +and then talking a little +bit about special relativity, + +and then repeating +both calculations + +with a special relativity +situation where + +we'll be talking about light +rays and velocities that + +might be comparable +to the speed of light. + +So see you folks on +Thursday, but maybe I'll + +see some of you at my +office hour tomorrow. + +And I will send an email about +where exactly that office + +hour will take place. \ No newline at end of file diff --git a/50Tla309i7o.txt b/50Tla309i7o.txt new file mode 100644 index 0000000000000000000000000000000000000000..c4767bdc9d04b403f11ba62739545255624cd54b --- /dev/null +++ b/50Tla309i7o.txt @@ -0,0 +1,1651 @@ +align:start position:0% + +next is this phenomenon that when you + + align:start position:0% +next is this phenomenon that when you + + + align:start position:0% +next is this phenomenon that when you +have a wave packet and it moves it can + + align:start position:0% +have a wave packet and it moves it can + + + align:start position:0% +have a wave packet and it moves it can +change shape and get distorted and that + + align:start position:0% +change shape and get distorted and that + + + align:start position:0% +change shape and get distorted and that +is a very nice phenomenon that takes + + align:start position:0% +is a very nice phenomenon that takes + + + align:start position:0% +is a very nice phenomenon that takes +place in general and causes the + + align:start position:0% +place in general and causes the + + + align:start position:0% +place in general and causes the +technological complications and it's + + align:start position:0% +technological complications and it's + + + align:start position:0% +technological complications and it's +conceptually interesting so let's let's + + align:start position:0% +conceptually interesting so let's let's + + + align:start position:0% +conceptually interesting so let's let's +discuss it so it's still wave packets + + align:start position:0% +discuss it so it's still wave packets + + + align:start position:0% +discuss it so it's still wave packets +but now we have to go back and an add + + align:start position:0% +but now we have to go back and an add + + + align:start position:0% +but now we have to go back and an add +some time to it so shape changes so we + + align:start position:0% +some time to it so shape changes so we + + + align:start position:0% +some time to it so shape changes so we +had a sigh of X and T is equal 1 over + + align:start position:0% +had a sigh of X and T is equal 1 over + + + align:start position:0% +had a sigh of X and T is equal 1 over +square root of 2 pi v ke e to the ikx e + + align:start position:0% +square root of 2 pi v ke e to the ikx e + + + align:start position:0% +square root of 2 pi v ke e to the ikx e +to the minus I Omega of K T and what did + + align:start position:0% +to the minus I Omega of K T and what did + + + align:start position:0% +to the minus I Omega of K T and what did +we do with this to analyze how it + + align:start position:0% +we do with this to analyze how it + + + align:start position:0% +we do with this to analyze how it +propagates we expanded Omega of K as + + align:start position:0% +propagates we expanded Omega of K as + + + align:start position:0% +propagates we expanded Omega of K as +Omega of K naught which again this + + align:start position:0% +Omega of K naught which again this + + + align:start position:0% +Omega of K naught which again this +quantity centered and peaks around K + + align:start position:0% +quantity centered and peaks around K + + + align:start position:0% +quantity centered and peaks around K +naught plus K minus K naught times the + + align:start position:0% +naught plus K minus K naught times the + + + align:start position:0% +naught plus K minus K naught times the +Omega DK at K naught plus one-half K + + align:start position:0% +Omega DK at K naught plus one-half K + + + align:start position:0% +Omega DK at K naught plus one-half K +minus K naught squared the second Omega + + align:start position:0% +minus K naught squared the second Omega + + + align:start position:0% +minus K naught squared the second Omega +DK squared at k naught and it might seem + + align:start position:0% +DK squared at k naught and it might seem + + + align:start position:0% +DK squared at k naught and it might seem +that this goes on forever and what did + + align:start position:0% +that this goes on forever and what did + + + align:start position:0% +that this goes on forever and what did +we do before we looked at this thing and + + align:start position:0% +we do before we looked at this thing and + + + align:start position:0% +we do before we looked at this thing and +we did the integral with this term and + + align:start position:0% +we did the integral with this term and + + + align:start position:0% +we did the integral with this term and +nor the next and with this term we + + align:start position:0% +nor the next and with this term we + + + align:start position:0% +nor the next and with this term we +discovered that the profile moves with + + align:start position:0% +discovered that the profile moves with + + + align:start position:0% +discovered that the profile moves with +this velocity the group velocity now we + + align:start position:0% +this velocity the group velocity now we + + + align:start position:0% +this velocity the group velocity now we +want to go back and at least get an idea + + align:start position:0% +want to go back and at least get an idea + + + align:start position:0% +want to go back and at least get an idea +of how this term could change the result + + align:start position:0% +of how this term could change the result + + + align:start position:0% +of how this term could change the result +and it would change the result by + + align:start position:0% +and it would change the result by + + + align:start position:0% +and it would change the result by +deforming the shape of the packet so it + + align:start position:0% +deforming the shape of the packet so it + + + align:start position:0% +deforming the shape of the packet so it +is of interest to know for example how + + align:start position:0% +is of interest to know for example how + + + align:start position:0% +is of interest to know for example how +long you have to wait before your packet + + align:start position:0% +long you have to wait before your packet + + + align:start position:0% +long you have to wait before your packet +gets overly deformed or how do you + + align:start position:0% +gets overly deformed or how do you + + + align:start position:0% +gets overly deformed or how do you +evolve a packet so we need to recall + + align:start position:0% +evolve a packet so we need to recall + + + align:start position:0% +evolve a packet so we need to recall +this derivative so the Omega the K is + + align:start position:0% +this derivative so the Omega the K is + + + align:start position:0% +this derivative so the Omega the K is +the same as the EDP by multiplying by H + + align:start position:0% +the same as the EDP by multiplying by H + + + align:start position:0% +the same as the EDP by multiplying by H +bar and this you remember was P over m + + align:start position:0% + + + + align:start position:0% + +the EDP is P over m and is equal to H + + align:start position:0% +the EDP is P over m and is equal to H + + + align:start position:0% +the EDP is P over m and is equal to H +Bar K over m so the second Omega the K + + align:start position:0% +Bar K over m so the second Omega the K + + + align:start position:0% +Bar K over m so the second Omega the K +squared + + align:start position:0% +squared + + + align:start position:0% +squared +I must differentiate the first + + align:start position:0% +I must differentiate the first + + + align:start position:0% +I must differentiate the first +derivative with respect to K so I + + align:start position:0% +derivative with respect to K so I + + + align:start position:0% +derivative with respect to K so I +differentiate the first derivative with + + align:start position:0% +differentiate the first derivative with + + + align:start position:0% +differentiate the first derivative with +respect to K now I get just H bar over m + + align:start position:0% +respect to K now I get just H bar over m + + + align:start position:0% +respect to K now I get just H bar over m +which is quite nice and the third + + align:start position:0% +which is quite nice and the third + + + align:start position:0% +which is quite nice and the third +derivative the three Omega the case cube + + align:start position:0% +derivative the three Omega the case cube + + + align:start position:0% +derivative the three Omega the case cube +is zero and therefore I didn't have to + + align:start position:0% +is zero and therefore I didn't have to + + + align:start position:0% +is zero and therefore I didn't have to +worry about these terms the serious + + align:start position:0% +worry about these terms the serious + + + align:start position:0% +worry about these terms the serious +terminates the Taylor series terminates + + align:start position:0% +terminates the Taylor series terminates + + + align:start position:0% +terminates the Taylor series terminates +for mr. yes + + align:start position:0% + + + + align:start position:0% + +that's right + + align:start position:0% + + + + align:start position:0% + +so what is it that we get well this term + + align:start position:0% +so what is it that we get well this term + + + align:start position:0% +so what is it that we get well this term +is roughly then 1/2 K minus K naught + + align:start position:0% +is roughly then 1/2 K minus K naught + + + align:start position:0% +is roughly then 1/2 K minus K naught +squared times H bar over m and we can go + + align:start position:0% +squared times H bar over m and we can go + + + align:start position:0% +squared times H bar over m and we can go +back to the integral that we're trying + + align:start position:0% +back to the integral that we're trying + + + align:start position:0% +back to the integral that we're trying +to do we don't do it again or not by any + + align:start position:0% +to do we don't do it again or not by any + + + align:start position:0% +to do we don't do it again or not by any +means but just observe what's going on + + align:start position:0% +means but just observe what's going on + + + align:start position:0% +means but just observe what's going on +there and we have an e to the minus I + + align:start position:0% +there and we have an e to the minus I + + + align:start position:0% +there and we have an e to the minus I +Omega of K T that we did take into + + align:start position:0% +Omega of K T that we did take into + + + align:start position:0% +Omega of K T that we did take into +account but the term that we're dropping + + align:start position:0% +account but the term that we're dropping + + + align:start position:0% +account but the term that we're dropping +now is a term that is minus I Omega of K + + align:start position:0% +now is a term that is minus I Omega of K + + + align:start position:0% +now is a term that is minus I Omega of K +well whatever we have here 1/2 K minus K + + align:start position:0% +well whatever we have here 1/2 K minus K + + + align:start position:0% +well whatever we have here 1/2 K minus K +naught squared H bar over m t that's the + + align:start position:0% +naught squared H bar over m t that's the + + + align:start position:0% +naught squared H bar over m t that's the +face that we ignored before + + align:start position:0% + + + + align:start position:0% + +but now we'll just say that we expect + + align:start position:0% +but now we'll just say that we expect + + + align:start position:0% +but now we'll just say that we expect +therefore that the shape doesn't change + + align:start position:0% +therefore that the shape doesn't change + + + align:start position:0% +therefore that the shape doesn't change +as long as we can ignore this face and + + align:start position:0% +as long as we can ignore this face and + + + align:start position:0% +as long as we can ignore this face and +this face would start changing shape of + + align:start position:0% +this face would start changing shape of + + + align:start position:0% +this face would start changing shape of +the object so so our statement is going + + align:start position:0% +the object so so our statement is going + + + align:start position:0% +the object so so our statement is going +to be that we have no shape so let's + + align:start position:0% +to be that we have no shape so let's + + + align:start position:0% +to be that we have no shape so let's +imagine you started with a packet that + + align:start position:0% +imagine you started with a packet that + + + align:start position:0% +imagine you started with a packet that +some time T equals zero and then you let + + align:start position:0% +some time T equals zero and then you let + + + align:start position:0% +some time T equals zero and then you let +time go by well there's some numbers + + align:start position:0% +time go by well there's some numbers + + + align:start position:0% +time go by well there's some numbers +here and time is increasing at some + + align:start position:0% +here and time is increasing at some + + + align:start position:0% +here and time is increasing at some +point this face is going to become + + align:start position:0% +point this face is going to become + + + align:start position:0% +point this face is going to become +unknowable and it's going to start + + align:start position:0% +unknowable and it's going to start + + + align:start position:0% +unknowable and it's going to start +affecting everything but we have no + + align:start position:0% +affecting everything but we have no + + + align:start position:0% +affecting everything but we have no +shape change or no appreciable shape + + align:start position:0% +shape change or no appreciable shape + + + align:start position:0% +shape change or no appreciable shape +change as long as this quantity is much + + align:start position:0% +change as long as this quantity is much + + + align:start position:0% +change as long as this quantity is much +less than 1 so as long as say K minus K + + align:start position:0% +less than 1 so as long as say K minus K + + + align:start position:0% +less than 1 so as long as say K minus K +naught squared H bar over m absolute + + align:start position:0% +naught squared H bar over m absolute + + + align:start position:0% +naught squared H bar over m absolute +value of T is much less than 1 no shape + + align:start position:0% +value of T is much less than 1 no shape + + + align:start position:0% +value of T is much less than 1 no shape +change now it's convenient to write it + + align:start position:0% +change now it's convenient to write it + + + align:start position:0% +change now it's convenient to write it +in terms of things that are more + + align:start position:0% +in terms of things that are more + + + align:start position:0% +in terms of things that are more +familiar so we should estimate this + + align:start position:0% +familiar so we should estimate this + + + align:start position:0% +familiar so we should estimate this +thing now we're doing estimates in a + + align:start position:0% +thing now we're doing estimates in a + + + align:start position:0% +thing now we're doing estimates in a +very direct and rough way here but look + + align:start position:0% +very direct and rough way here but look + + + align:start position:0% +very direct and rough way here but look +your integrals are around K naught and + + align:start position:0% +your integrals are around K naught and + + + align:start position:0% +your integrals are around K naught and +as you remember they just extend a + + align:start position:0% +as you remember they just extend a + + + align:start position:0% +as you remember they just extend a +little bit because it has some width so + + align:start position:0% +little bit because it has some width so + + + align:start position:0% +little bit because it has some width so +K minus K not as soon as you do the + + align:start position:0% +K minus K not as soon as you do the + + + align:start position:0% +K minus K not as soon as you do the +interval over k you're basically + + align:start position:0% +interval over k you're basically + + + align:start position:0% +interval over k you're basically +saying this thing is about the size of + + align:start position:0% +saying this thing is about the size of + + + align:start position:0% +saying this thing is about the size of +the uncertainty in case so I'll put here + + align:start position:0% +the uncertainty in case so I'll put here + + + align:start position:0% +the uncertainty in case so I'll put here +Delta K squared then you have H bar t + + align:start position:0% +Delta K squared then you have H bar t + + + align:start position:0% +Delta K squared then you have H bar t +over m much less than 1 now H bar times + + align:start position:0% +over m much less than 1 now H bar times + + + align:start position:0% +over m much less than 1 now H bar times +Delta K is Delta P so this equation is + + align:start position:0% +Delta K is Delta P so this equation is + + + align:start position:0% +Delta K is Delta P so this equation is +also of the form Delta P squared T over + + align:start position:0% +also of the form Delta P squared T over + + + align:start position:0% +also of the form Delta P squared T over +H bar m much less than 1 there are + + align:start position:0% +H bar m much less than 1 there are + + + align:start position:0% +H bar m much less than 1 there are +several forms of this equation with this + + align:start position:0% +several forms of this equation with this + + + align:start position:0% +several forms of this equation with this +kind of noise so this is a particularly + + align:start position:0% +kind of noise so this is a particularly + + + align:start position:0% +kind of noise so this is a particularly +nice form so if you know the uncertainty + + align:start position:0% +nice form so if you know the uncertainty + + + align:start position:0% +nice form so if you know the uncertainty +in momentum of your packet or wave + + align:start position:0% +in momentum of your packet or wave + + + align:start position:0% +in momentum of your packet or wave +packet you know up to what time you can + + align:start position:0% +packet you know up to what time you can + + + align:start position:0% +packet you know up to what time you can +wait and there's no big deformation of + + align:start position:0% +wait and there's no big deformation of + + + align:start position:0% +wait and there's no big deformation of +this wave packet another thing you can + + align:start position:0% +this wave packet another thing you can + + + align:start position:0% +this wave packet another thing you can +do is involved in certainty in X because + + align:start position:0% +do is involved in certainty in X because + + + align:start position:0% +do is involved in certainty in X because +well Delta P Delta X is equal to H bar + + align:start position:0% +well Delta P Delta X is equal to H bar + + + align:start position:0% +well Delta P Delta X is equal to H bar +so we can do that + + align:start position:0% + + + + align:start position:0% + +and so with delta P times Delta X equal + + align:start position:0% +and so with delta P times Delta X equal + + + align:start position:0% +and so with delta P times Delta X equal +to about h-bar you can write T less than + + align:start position:0% +to about h-bar you can write T less than + + + align:start position:0% +to about h-bar you can write T less than +h-bar over m over Delta P squared which + + align:start position:0% +h-bar over m over Delta P squared which + + + align:start position:0% +h-bar over m over Delta P squared which +would be H squared Delta x squared you + + align:start position:0% +would be H squared Delta x squared you + + + align:start position:0% +would be H squared Delta x squared you +think I'm getting it right yep so T much + + align:start position:0% +think I'm getting it right yep so T much + + + align:start position:0% +think I'm getting it right yep so T much +less than M over H bar Delta x squared + + align:start position:0% +less than M over H bar Delta x squared + + + align:start position:0% +less than M over H bar Delta x squared +that's another way you could write this + + align:start position:0% +that's another way you could write this + + + align:start position:0% +that's another way you could write this +inequality there is one way to write + + align:start position:0% +inequality there is one way to write + + + align:start position:0% +inequality there is one way to write +inequality that you can intuitively feel + + align:start position:0% +inequality that you can intuitively feel + + + align:start position:0% +inequality that you can intuitively feel +you understand what's happening and take + + align:start position:0% +you understand what's happening and take + + + align:start position:0% +you understand what's happening and take +this form a from a write it as Delta P P + + align:start position:0% +this form a from a write it as Delta P P + + + align:start position:0% +this form a from a write it as Delta P P +over m less than h-bar over Delta P and + + align:start position:0% +over m less than h-bar over Delta P and + + + align:start position:0% +over m less than h-bar over Delta P and +H bar over Delta P is Delta X okay you + + align:start position:0% +H bar over Delta P is Delta X okay you + + + align:start position:0% +H bar over Delta P is Delta X okay you +go Delta P over m t less than or equal + + align:start position:0% +go Delta P over m t less than or equal + + + align:start position:0% +go Delta P over m t less than or equal +much less I'm sorry + + align:start position:0% +much less I'm sorry + + + align:start position:0% +much less I'm sorry +much less than Delta X + + align:start position:0% + + + + align:start position:0% + +I think this is understandable you see + + align:start position:0% +I think this is understandable you see + + + align:start position:0% +I think this is understandable you see +why why does the packet change shape the + + align:start position:0% +why why does the packet change shape the + + + align:start position:0% +why why does the packet change shape the +reason it changes shape is because the + + align:start position:0% +reason it changes shape is because the + + + align:start position:0% +reason it changes shape is because the +group velocity is not the same for all + + align:start position:0% +group velocity is not the same for all + + + align:start position:0% +group velocity is not the same for all +the frequencies the packet mostly moves + + align:start position:0% +the frequencies the packet mostly moves + + + align:start position:0% +the frequencies the packet mostly moves +with K naught and we ever rated the + + align:start position:0% +with K naught and we ever rated the + + + align:start position:0% +with K naught and we ever rated the +group velocity in K naught but if it + + align:start position:0% +group velocity in K naught but if it + + + align:start position:0% +group velocity in K naught but if it +would have a definite velocity would + + align:start position:0% +would have a definite velocity would + + + align:start position:0% +would have a definite velocity would +have a definite velocity would have a + + align:start position:0% +have a definite velocity would have a + + + align:start position:0% +have a definite velocity would have a +definite momentum but that's not + + align:start position:0% +definite momentum but that's not + + + align:start position:0% +definite momentum but that's not +possible these things have uncertainty + + align:start position:0% +possible these things have uncertainty + + + align:start position:0% +possible these things have uncertainty +in momentum and they have uncertainty in + + align:start position:0% +in momentum and they have uncertainty in + + + align:start position:0% +in momentum and they have uncertainty in +K that we use it to ride it so different + + align:start position:0% +K that we use it to ride it so different + + + align:start position:0% +K that we use it to ride it so different +parts of the wave can move with + + align:start position:0% +parts of the wave can move with + + + align:start position:0% +parts of the wave can move with +different velocities different group + + align:start position:0% +different velocities different group + + + align:start position:0% +different velocities different group +velocities the group velocity you have a + + align:start position:0% +velocities the group velocity you have a + + + align:start position:0% +velocities the group velocity you have a +later that K naught but some part of the + + align:start position:0% +later that K naught but some part of the + + + align:start position:0% +later that K naught but some part of the +packet is is propagating with group + + align:start position:0% +packet is is propagating with group + + + align:start position:0% +packet is is propagating with group +velocities that are near K naught but + + align:start position:0% +velocities that are near K naught but + + + align:start position:0% +velocities that are near K naught but +not exactly there so you have a + + align:start position:0% +not exactly there so you have a + + + align:start position:0% +not exactly there so you have a +dispersion in the velocity which is an + + align:start position:0% +dispersion in the velocity which is an + + + align:start position:0% +dispersion in the velocity which is an +uncertainty in the velocity or an + + align:start position:0% +uncertainty in the velocity or an + + + align:start position:0% +uncertainty in the velocity or an +uncertainty in the momentum think the + + align:start position:0% +uncertainty in the momentum think the + + + align:start position:0% +uncertainty in the momentum think the +momentum divided by mass is velocity so + + align:start position:0% +momentum divided by mass is velocity so + + + align:start position:0% +momentum divided by mass is velocity so +here it is an uncertainty in the + + align:start position:0% +here it is an uncertainty in the + + + align:start position:0% +here it is an uncertainty in the +velocity and if you multiply the + + align:start position:0% +velocity and if you multiply the + + + align:start position:0% +velocity and if you multiply the +uncertainty in the velocity times this + + align:start position:0% +uncertainty in the velocity times this + + + align:start position:0% +uncertainty in the velocity times this +time that you can wait then the change + + align:start position:0% +time that you can wait then the change + + + align:start position:0% +time that you can wait then the change +in shape is not much + + align:start position:0% +in shape is not much + + + align:start position:0% +in shape is not much +if those is this product which is the + + align:start position:0% +if those is this product which is the + + + align:start position:0% +if those is this product which is the +difference of how one part moves with + + align:start position:0% +difference of how one part moves with + + + align:start position:0% +difference of how one part moves with +respect to the other difference of + + align:start position:0% +respect to the other difference of + + + align:start position:0% +respect to the other difference of +relative time is still smaller than the + + align:start position:0% +relative time is still smaller than the + + + align:start position:0% +relative time is still smaller than the +sort of uncertainty that controls the + + align:start position:0% +sort of uncertainty that controls the + + + align:start position:0% +sort of uncertainty that controls the +shape of the packet so the packet has a + + align:start position:0% +shape of the packet so the packet has a + + + align:start position:0% +shape of the packet so the packet has a +delta X a delta X and as long as this + + align:start position:0% +delta X a delta X and as long as this + + + align:start position:0% +delta X a delta X and as long as this +part the left part of the packet and the + + align:start position:0% +part the left part of the packet and the + + + align:start position:0% +part the left part of the packet and the +top of the packet the diff + + align:start position:0% +top of the packet the diff + + + align:start position:0% +top of the packet the diff +of velocities times the time it just + + align:start position:0% +of velocities times the time it just + + + align:start position:0% +of velocities times the time it just +still compared to Delta X is small then + + align:start position:0% +still compared to Delta X is small then + + + align:start position:0% +still compared to Delta X is small then +that the thing doesn't change much so I + + align:start position:0% +that the thing doesn't change much so I + + + align:start position:0% +that the thing doesn't change much so I +think this is one neat way of seeing + + align:start position:0% +think this is one neat way of seeing + + + align:start position:0% +think this is one neat way of seeing +what an equation that you sometimes use + + align:start position:0% +what an equation that you sometimes use + + + align:start position:0% +what an equation that you sometimes use +in this form sometimes use in this form + + align:start position:0% +in this form sometimes use in this form + + + align:start position:0% +in this form sometimes use in this form +it's just things that you can use in + + align:start position:0% +it's just things that you can use in + + + align:start position:0% +it's just things that you can use in +different ways so for example I will not + + align:start position:0% +different ways so for example I will not + + + align:start position:0% +different ways so for example I will not +well I can do this a little exercise + + align:start position:0% +well I can do this a little exercise + + + align:start position:0% +well I can do this a little exercise +exercise if you have Delta X equals 10 + + align:start position:0% +exercise if you have Delta X equals 10 + + + align:start position:0% +exercise if you have Delta X equals 10 +to the minus 10 meters that's atomic + + align:start position:0% +to the minus 10 meters that's atomic + + + align:start position:0% +to the minus 10 meters that's atomic +size for an electron what is the how + + align:start position:0% +size for an electron what is the how + + + align:start position:0% +size for an electron what is the how +long does it remain localized so you + + align:start position:0% +long does it remain localized so you + + + align:start position:0% +long does it remain localized so you +have an electron and you produce a party + + align:start position:0% +have an electron and you produce a party + + + align:start position:0% +have an electron and you produce a party +then localize it to the size of an atom + + align:start position:0% +then localize it to the size of an atom + + + align:start position:0% +then localize it to the size of an atom +how long can you wait before this + + align:start position:0% +how long can you wait before this + + + align:start position:0% +how long can you wait before this +electron is just all over the room + + align:start position:0% +electron is just all over the room + + + align:start position:0% +electron is just all over the room +well we when we say this T and we say + + align:start position:0% +well we when we say this T and we say + + + align:start position:0% +well we when we say this T and we say +this time we're basically saying that + + align:start position:0% +this time we're basically saying that + + + align:start position:0% +this time we're basically saying that +it's roughly still there maybe grew 20% + + align:start position:0% +it's roughly still there maybe grew 20% + + + align:start position:0% +it's roughly still there maybe grew 20% +30% but what's the rough time that you + + align:start position:0% +30% but what's the rough time that you + + + align:start position:0% +30% but what's the rough time that you +can expect that it stays there so in + + align:start position:0% +can expect that it stays there so in + + + align:start position:0% +can expect that it stays there so in +this case we can use just this formula + + align:start position:0% +this case we can use just this formula + + + align:start position:0% +this case we can use just this formula +and we say the time could be + + align:start position:0% +and we say the time could be + + + align:start position:0% +and we say the time could be +approximately m over H bar Delta x + + align:start position:0% +approximately m over H bar Delta x + + + align:start position:0% +approximately m over H bar Delta x +squared it's fun to see the numbers you + + align:start position:0% +squared it's fun to see the numbers you + + + align:start position:0% +squared it's fun to see the numbers you +would calculate it with MC squared over + + align:start position:0% +would calculate it with MC squared over + + + align:start position:0% +would calculate it with MC squared over +H bar C times Delta X + + align:start position:0% +H bar C times Delta X + + + align:start position:0% +H bar C times Delta X +oversee this squared the answer is about + + align:start position:0% +oversee this squared the answer is about + + + align:start position:0% +oversee this squared the answer is about +10 to the minus 16 seconds not much this + + align:start position:0% +10 to the minus 16 seconds not much this + + + align:start position:0% +10 to the minus 16 seconds not much this +this is kind of a practical issue in + + align:start position:0% +this is kind of a practical issue in + + + align:start position:0% +this is kind of a practical issue in +accelerators as well particle physics + + align:start position:0% +accelerators as well particle physics + + + align:start position:0% +accelerators as well particle physics +accelerators they conserve bunches a + + align:start position:0% +accelerators they conserve bunches a + + + align:start position:0% +accelerators they conserve bunches a +little bunch of protons in the LHC it's + + align:start position:0% +little bunch of protons in the LHC it's + + + align:start position:0% +little bunch of protons in the LHC it's +a little cylinder in which the wave + + align:start position:0% +a little cylinder in which the wave + + + align:start position:0% +a little cylinder in which the wave +functions of the protons are all + + align:start position:0% +functions of the protons are all + + + align:start position:0% +functions of the protons are all +collimated very thin short a couple of + + align:start position:0% +collimated very thin short a couple of + + + align:start position:0% +collimated very thin short a couple of +centimeters short and after going around + + align:start position:0% +centimeters short and after going around + + + align:start position:0% +centimeters short and after going around +many times around accelerator they + + align:start position:0% +many times around accelerator they + + + align:start position:0% +many times around accelerator they +always have to be compressed and kept + + align:start position:0% +always have to be compressed and kept + + + align:start position:0% +always have to be compressed and kept +back sent back to shape because just of + + align:start position:0% +back sent back to shape because just of + + + align:start position:0% +back sent back to shape because just of +diffusion these things just propagate + + align:start position:0% +diffusion these things just propagate + + + align:start position:0% +diffusion these things just propagate +and so it's a rather important thing \ No newline at end of file diff --git a/50oEJs-HZHQ.txt b/50oEJs-HZHQ.txt new file mode 100644 index 0000000000000000000000000000000000000000..c974fb9fd7d5b4051c11d6aed1eee3f74caaed0d --- /dev/null +++ b/50oEJs-HZHQ.txt @@ -0,0 +1,8363 @@ +align:start position:0% + +last time we started talking about Ross + + align:start position:0% +last time we started talking about Ross + + + align:start position:0% +last time we started talking about Ross +theorem and we showed a Fourier analytic + + align:start position:0% +theorem and we showed a Fourier analytic + + + align:start position:0% +theorem and we showed a Fourier analytic +proof of Ross theorem in the finite + + align:start position:0% +proof of Ross theorem in the finite + + + align:start position:0% +proof of Ross theorem in the finite +field model so roster in F 3 to the N + + align:start position:0% +field model so roster in F 3 to the N + + + align:start position:0% +field model so roster in F 3 to the N +and I want you today show you how to + + align:start position:0% +and I want you today show you how to + + + align:start position:0% +and I want you today show you how to +modify that proof to work in integers + + align:start position:0% +modify that proof to work in integers + + + align:start position:0% +modify that proof to work in integers +and this will be basically Ross original + + align:start position:0% +and this will be basically Ross original + + + align:start position:0% +and this will be basically Ross original +proof office theorem so what we'll prove + + align:start position:0% +proof office theorem so what we'll prove + + + align:start position:0% +proof office theorem so what we'll prove +today is the statement that the size of + + align:start position:0% +today is the statement that the size of + + + align:start position:0% +today is the statement that the size of +the largest three ap3 subset of 1 to n + + align:start position:0% +the largest three ap3 subset of 1 to n + + + align:start position:0% +the largest three ap3 subset of 1 to n +is at most and divided by log log n ok + + align:start position:0% +is at most and divided by log log n ok + + + align:start position:0% +is at most and divided by log log n ok +so we'll proof a bound of this form the + + align:start position:0% +so we'll proof a bound of this form the + + + align:start position:0% +so we'll proof a bound of this form the +strategy of this proof will be very + + align:start position:0% +strategy of this proof will be very + + + align:start position:0% +strategy of this proof will be very +similar to the one that we have from + + align:start position:0% +similar to the one that we have from + + + align:start position:0% +similar to the one that we have from +last time so let me review for you what + + align:start position:0% +last time so let me review for you what + + + align:start position:0% +last time so let me review for you what +is the strategy + + align:start position:0% + + + + align:start position:0% + +so from last time the proof had three + + align:start position:0% +so from last time the proof had three + + + align:start position:0% +so from last time the proof had three +main steps in the first step we observed + + align:start position:0% +main steps in the first step we observed + + + align:start position:0% +main steps in the first step we observed +that if you are in a three AP three set + + align:start position:0% + + + + align:start position:0% + +then there exists a large Fourier + + align:start position:0% +then there exists a large Fourier + + + align:start position:0% +then there exists a large Fourier +coefficient from this Fourier + + align:start position:0% +coefficient from this Fourier + + + align:start position:0% +coefficient from this Fourier +coefficient we were able to extract a + + align:start position:0% +coefficient we were able to extract a + + + align:start position:0% +coefficient we were able to extract a +large subspace where there's a density + + align:start position:0% +large subspace where there's a density + + + align:start position:0% +large subspace where there's a density +increment I want to modify that strategy + + align:start position:0% +increment I want to modify that strategy + + + align:start position:0% +increment I want to modify that strategy +so that we can work in the integers + + align:start position:0% +so that we can work in the integers + + + align:start position:0% +so that we can work in the integers +unlike in f2 to the M where things were + + align:start position:0% +unlike in f2 to the M where things were + + + align:start position:0% +unlike in f2 to the M where things were +fairly nice and clean and because you + + align:start position:0% +fairly nice and clean and because you + + + align:start position:0% +fairly nice and clean and because you +have subspaces you can you know take a + + align:start position:0% +have subspaces you can you know take a + + + align:start position:0% +have subspaces you can you know take a +Fourier coefficient pass down to a + + align:start position:0% +Fourier coefficient pass down to a + + + align:start position:0% +Fourier coefficient pass down to a +subspace there's no subspaces there are + + align:start position:0% +subspace there's no subspaces there are + + + align:start position:0% +subspace there's no subspaces there are +no subspaces in integers so we'll have + + align:start position:0% +no subspaces in integers so we'll have + + + align:start position:0% +no subspaces in integers so we'll have +to do something slightly different but + + align:start position:0% +to do something slightly different but + + + align:start position:0% +to do something slightly different but +in the same spirit so you'll find a + + align:start position:0% +in the same spirit so you'll find a + + + align:start position:0% +in the same spirit so you'll find a +large Fourier coefficient + + align:start position:0% + + + + align:start position:0% + +and we will find that there's density + + align:start position:0% +and we will find that there's density + + + align:start position:0% +and we will find that there's density +increment when you restrict not to + + align:start position:0% +increment when you restrict not to + + + align:start position:0% +increment when you restrict not to +subspaces but what could play the role + + align:start position:0% +subspaces but what could play the role + + + align:start position:0% +subspaces but what could play the role +of subspaces when it comes to the + + align:start position:0% +of subspaces when it comes to the + + + align:start position:0% +of subspaces when it comes to the +integers so I want something which looks + + align:start position:0% +integers so I want something which looks + + + align:start position:0% +integers so I want something which looks +like a smaller version of the original + + align:start position:0% +like a smaller version of the original + + + align:start position:0% +like a smaller version of the original +space so instead of open integers if we + + align:start position:0% +space so instead of open integers if we + + + align:start position:0% +space so instead of open integers if we +restrict to a sub progression so to a + + align:start position:0% +restrict to a sub progression so to a + + + align:start position:0% +restrict to a sub progression so to a +smaller arithmetic progression and we'll + + align:start position:0% +smaller arithmetic progression and we'll + + + align:start position:0% +smaller arithmetic progression and we'll +show that you can restrict to a sub + + align:start position:0% +show that you can restrict to a sub + + + align:start position:0% +show that you can restrict to a sub +progression where you can obtain density + + align:start position:0% +progression where you can obtain density + + + align:start position:0% +progression where you can obtain density +increment or restrict integers to + + align:start position:0% +increment or restrict integers to + + + align:start position:0% +increment or restrict integers to +something smaller and then same as last + + align:start position:0% +something smaller and then same as last + + + align:start position:0% +something smaller and then same as last +time we can iterate this inner increment + + align:start position:0% + + + + align:start position:0% + +to obtain the conclusion that you have + + align:start position:0% +to obtain the conclusion that you have + + + align:start position:0% +to obtain the conclusion that you have +an upper bound on the size of this 383 + + align:start position:0% +an upper bound on the size of this 383 + + + align:start position:0% +an upper bound on the size of this 383 +set okay so that's the strategy so you + + align:start position:0% +set okay so that's the strategy so you + + + align:start position:0% +set okay so that's the strategy so you +see the same strategy as the one we did + + align:start position:0% +see the same strategy as the one we did + + + align:start position:0% +see the same strategy as the one we did +last time and many of the ingredients + + align:start position:0% +last time and many of the ingredients + + + align:start position:0% +last time and many of the ingredients +will have parallels but the execution + + align:start position:0% +will have parallels but the execution + + + align:start position:0% +will have parallels but the execution +will be slightly different especially in + + align:start position:0% +will be slightly different especially in + + + align:start position:0% +will be slightly different especially in +the second step where because we no + + align:start position:0% +the second step where because we no + + + align:start position:0% +the second step where because we no +longer have subspaces which are nice and + + align:start position:0% +longer have subspaces which are nice and + + + align:start position:0% +longer have subspaces which are nice and +clean so that's why we started with a + + align:start position:0% +clean so that's why we started with a + + + align:start position:0% +clean so that's why we started with a +finite fuel model just to show how + + align:start position:0% +finite fuel model just to show how + + + align:start position:0% +finite fuel model just to show how +things work in a slightly easier setting + + align:start position:0% +things work in a slightly easier setting + + + align:start position:0% +things work in a slightly easier setting +and today we'll see how to do the same + + align:start position:0% +and today we'll see how to do the same + + + align:start position:0% +and today we'll see how to do the same +kind of strategy here where there's + + align:start position:0% +kind of strategy here where there's + + + align:start position:0% +kind of strategy here where there's +going to be a bit more work but not too + + align:start position:0% +going to be a bit more work but not too + + + align:start position:0% +going to be a bit more work but not too +much more bit more work so before we + + align:start position:0% +much more bit more work so before we + + + align:start position:0% +much more bit more work so before we +start any questions + + align:start position:0% + + + + align:start position:0% + +all right so last time I used the proof + + align:start position:0% +all right so last time I used the proof + + + align:start position:0% +all right so last time I used the proof +of rostrum as an excuse to introduce + + align:start position:0% +of rostrum as an excuse to introduce + + + align:start position:0% +of rostrum as an excuse to introduce +Fourier analysis and we're gonna see + + align:start position:0% +Fourier analysis and we're gonna see + + + align:start position:0% +Fourier analysis and we're gonna see +basically the same kind of Fourier + + align:start position:0% +basically the same kind of Fourier + + + align:start position:0% +basically the same kind of Fourier +analysis but it's going to take on a + + align:start position:0% +analysis but it's going to take on a + + + align:start position:0% +analysis but it's going to take on a +slightly different form because we're + + align:start position:0% +slightly different form because we're + + + align:start position:0% +slightly different form because we're +not working at three to the N I work + + align:start position:0% +not working at three to the N I work + + + align:start position:0% +not working at three to the N I work +working inside the integers and there's + + align:start position:0% +working inside the integers and there's + + + align:start position:0% +working inside the integers and there's +a general theory of Fourier analysis on + + align:start position:0% +a general theory of Fourier analysis on + + + align:start position:0% +a general theory of Fourier analysis on +the group abelian groups I don't want to + + align:start position:0% +the group abelian groups I don't want to + + + align:start position:0% +the group abelian groups I don't want to +go into that theory because it's I want + + align:start position:0% +go into that theory because it's I want + + + align:start position:0% +go into that theory because it's I want +to focus on the specific case but the + + align:start position:0% +to focus on the specific case but the + + + align:start position:0% +to focus on the specific case but the +points are given in a median group you + + align:start position:0% +points are given in a median group you + + + align:start position:0% +points are given in a median group you +always have a dual group do group of + + align:start position:0% +always have a dual group do group of + + + align:start position:0% +always have a dual group do group of +characters and they play the role of + + align:start position:0% +characters and they play the role of + + + align:start position:0% +characters and they play the role of +Fourier transform specifically in the + + align:start position:0% +Fourier transform specifically in the + + + align:start position:0% +Fourier transform specifically in the +case of Z we have the following Fourier + + align:start position:0% +case of Z we have the following Fourier + + + align:start position:0% +case of Z we have the following Fourier +transform so the dual group of Z turns + + align:start position:0% +transform so the dual group of Z turns + + + align:start position:0% +transform so the dual group of Z turns +out to be a torus so real numbers mod + + align:start position:0% +out to be a torus so real numbers mod + + + align:start position:0% +out to be a torus so real numbers mod +one and the Fourier transform it's the + + align:start position:0% +one and the Fourier transform it's the + + + align:start position:0% +one and the Fourier transform it's the +finest follows starting with a function + + align:start position:0% + + + + align:start position:0% + +the integers if you like let's say it's + + align:start position:0% +the integers if you like let's say it's + + + align:start position:0% +the integers if you like let's say it's +finally supported just to make our lives + + align:start position:0% +finally supported just to make our lives + + + align:start position:0% +finally supported just to make our lives +a bit easier don't have to deal with + + align:start position:0% +a bit easier don't have to deal with + + + align:start position:0% +a bit easier don't have to deal with +technicalities but in general the + + align:start position:0% +technicalities but in general the + + + align:start position:0% +technicalities but in general the +following formula holds we have this + + align:start position:0% +following formula holds we have this + + + align:start position:0% +following formula holds we have this +Fourier transform defined by setting F + + align:start position:0% +Fourier transform defined by setting F + + + align:start position:0% +Fourier transform defined by setting F +hat of theta to be the following some + + align:start position:0% + + + + align:start position:0% + +where this e is somewhat standard + + align:start position:0% +where this e is somewhat standard + + + align:start position:0% +where this e is somewhat standard +notation additive combinatorics it's e + + align:start position:0% +notation additive combinatorics it's e + + + align:start position:0% +notation additive combinatorics it's e +to the 2 pi I so it goes a fraction T + + align:start position:0% +to the 2 pi I so it goes a fraction T + + + align:start position:0% +to the 2 pi I so it goes a fraction T +around the complex unit circle okay so + + align:start position:0% +around the complex unit circle okay so + + + align:start position:0% +around the complex unit circle okay so +that's the Fourier transform on the + + align:start position:0% +that's the Fourier transform on the + + + align:start position:0% +that's the Fourier transform on the +integers you might have seen this before + + align:start position:0% +integers you might have seen this before + + + align:start position:0% +integers you might have seen this before +under a different name this is usually + + align:start position:0% +under a different name this is usually + + + align:start position:0% +under a different name this is usually +called for you serious you know the + + align:start position:0% +called for you serious you know the + + + align:start position:0% +called for you serious you know the +notation may be slightly different okay + + align:start position:0% +notation may be slightly different okay + + + align:start position:0% +notation may be slightly different okay +so that's that's always see today and + + align:start position:0% +so that's that's always see today and + + + align:start position:0% +so that's that's always see today and +this Fourier transform plays the same + + align:start position:0% +this Fourier transform plays the same + + + align:start position:0% +this Fourier transform plays the same +role as the Fourier transform from last + + align:start position:0% +role as the Fourier transform from last + + + align:start position:0% +role as the Fourier transform from last +time which was on the group F 3 to the M + + align:start position:0% +time which was on the group F 3 to the M + + + align:start position:0% +time which was on the group F 3 to the M +and just as in the last time we had a + + align:start position:0% +and just as in the last time we had a + + + align:start position:0% +and just as in the last time we had a +number of important identities and will + + align:start position:0% +number of important identities and will + + + align:start position:0% +number of important identities and will +have the same kinds of identities so let + + align:start position:0% +have the same kinds of identities so let + + + align:start position:0% +have the same kinds of identities so let +me remind you what they are and the + + align:start position:0% +me remind you what they are and the + + + align:start position:0% +me remind you what they are and the +proofs are all basically the same so I + + align:start position:0% +proofs are all basically the same so I + + + align:start position:0% +proofs are all basically the same so I +won't show you the proofs I've had 0 is + + align:start position:0% +won't show you the proofs I've had 0 is + + + align:start position:0% +won't show you the proofs I've had 0 is +simply the sum of over the domain we + + align:start position:0% +simply the sum of over the domain we + + + align:start position:0% +simply the sum of over the domain we +have this plancherel possible identity + + align:start position:0% +have this plancherel possible identity + + + align:start position:0% +have this plancherel possible identity +which tells us that if you look at the + + align:start position:0% +which tells us that if you look at the + + + align:start position:0% +which tells us that if you look at the +inner product by linear form in the + + align:start position:0% +inner product by linear form in the + + + align:start position:0% +inner product by linear form in the +physical space it equals to the inner + + align:start position:0% +physical space it equals to the inner + + + align:start position:0% +physical space it equals to the inner +product in the Fourier space + + align:start position:0% + + + + align:start position:0% + +in the physical space now use some in + + align:start position:0% +in the physical space now use some in + + + align:start position:0% +in the physical space now use some in +the frequency space you take integral + + align:start position:0% +the frequency space you take integral + + + align:start position:0% +the frequency space you take integral +over the torus or the circle in this + + align:start position:0% +over the torus or the circle in this + + + align:start position:0% +over the torus or the circle in this +case it's a one dimensional tourism + + align:start position:0% +case it's a one dimensional tourism + + + align:start position:0% +case it's a one dimensional tourism +there's also the Fourier inversion + + align:start position:0% +there's also the Fourier inversion + + + align:start position:0% +there's also the Fourier inversion +formula which now says that f of X is + + align:start position:0% +formula which now says that f of X is + + + align:start position:0% +formula which now says that f of X is +equal to F hat of theta G of X theta + + align:start position:0% +equal to F hat of theta G of X theta + + + align:start position:0% +equal to F hat of theta G of X theta +you can't equate theta from zero to one + + align:start position:0% +you can't equate theta from zero to one + + + align:start position:0% +you can't equate theta from zero to one +on the torus circle and third and + + align:start position:0% +on the torus circle and third and + + + align:start position:0% +on the torus circle and third and +finally there was this identity last + + align:start position:0% +finally there was this identity last + + + align:start position:0% +finally there was this identity last +time that related sweet home arithmetic + + align:start position:0% +time that related sweet home arithmetic + + + align:start position:0% +time that related sweet home arithmetic +progressions to the Fourier transform + + align:start position:0% +progressions to the Fourier transform + + + align:start position:0% +progressions to the Fourier transform +okay so this last one was slightly not + + align:start position:0% +okay so this last one was slightly not + + + align:start position:0% +okay so this last one was slightly not +asked I mean it's not as standard as the + + align:start position:0% +asked I mean it's not as standard as the + + + align:start position:0% +asked I mean it's not as standard as the +first several which are standard for + + align:start position:0% +first several which are standard for + + + align:start position:0% +first several which are standard for +your identities but this one will be + + align:start position:0% +your identities but this one will be + + + align:start position:0% +your identities but this one will be +useful to us so the identity relating + + align:start position:0% +useful to us so the identity relating + + + align:start position:0% +useful to us so the identity relating +the Fourier transform the three a piece + + align:start position:0% +the Fourier transform the three a piece + + + align:start position:0% +the Fourier transform the three a piece +now has the following form okay so if we + + align:start position:0% +now has the following form okay so if we + + + align:start position:0% +now has the following form okay so if we +define lambda of F and G and H to be the + + align:start position:0% +define lambda of F and G and H to be the + + + align:start position:0% +define lambda of F and G and H to be the +following sum which sums over all three + + align:start position:0% +following sum which sums over all three + + + align:start position:0% +following sum which sums over all three +a piece in the integers then one can + + align:start position:0% + + + + align:start position:0% + +write this expression in terms of the + + align:start position:0% +write this expression in terms of the + + + align:start position:0% +write this expression in terms of the +Fourier transform as follows + + align:start position:0% + + + + align:start position:0% + +so compared to this formula to the one + + align:start position:0% +so compared to this formula to the one + + + align:start position:0% +so compared to this formula to the one +that we saw from last time it's the same + + align:start position:0% +that we saw from last time it's the same + + + align:start position:0% +that we saw from last time it's the same +formula there are different domains + + align:start position:0% +formula there are different domains + + + align:start position:0% +formula there are different domains +where you're summing or integrating or + + align:start position:0% +where you're summing or integrating or + + + align:start position:0% +where you're summing or integrating or +it's the same formula and the proof is + + align:start position:0% +it's the same formula and the proof is + + + align:start position:0% +it's the same formula and the proof is +the same go look at the proof it's the + + align:start position:0% +the same go look at the proof it's the + + + align:start position:0% +the same go look at the proof it's the +same proof okay so these are the key + + align:start position:0% +same proof okay so these are the key + + + align:start position:0% +same proof okay so these are the key +Fourier things that we'll use and then + + align:start position:0% +Fourier things that we'll use and then + + + align:start position:0% +Fourier things that we'll use and then +we'll try to follow our nose with the + + align:start position:0% +we'll try to follow our nose with the + + + align:start position:0% +we'll try to follow our nose with the +same as a proof as last time and see + + align:start position:0% +same as a proof as last time and see + + + align:start position:0% +same as a proof as last time and see +where we can get so let me introduce one + + align:start position:0% +where we can get so let me introduce one + + + align:start position:0% +where we can get so let me introduce one +more notation so I'll write lambda sub 3 + + align:start position:0% +more notation so I'll write lambda sub 3 + + + align:start position:0% +more notation so I'll write lambda sub 3 +of F to be lambda of F F F three times + + align:start position:0% + + + + align:start position:0% + +okay well at this point if you + + align:start position:0% +okay well at this point if you + + + align:start position:0% +okay well at this point if you +understood the lecture from last time + + align:start position:0% +understood the lecture from last time + + + align:start position:0% +understood the lecture from last time +none of anything I've said so far should + + align:start position:0% +none of anything I've said so far should + + + align:start position:0% +none of anything I've said so far should +be surprising we are working integers so + + align:start position:0% +be surprising we are working integers so + + + align:start position:0% +be surprising we are working integers so +we should look at the corresponding + + align:start position:0% +we should look at the corresponding + + + align:start position:0% +we should look at the corresponding +Fourier transform in integers and if we + + align:start position:0% +Fourier transform in integers and if we + + + align:start position:0% +Fourier transform in integers and if we +follow your nose this is all the things + + align:start position:0% +follow your nose this is all the things + + + align:start position:0% +follow your nose this is all the things +that we're going to use okay so what was + + align:start position:0% +that we're going to use okay so what was + + + align:start position:0% +that we're going to use okay so what was +one of the first things we mentioned + + align:start position:0% +one of the first things we mentioned + + + align:start position:0% +one of the first things we mentioned +regarding the Fourier transform from + + align:start position:0% +regarding the Fourier transform from + + + align:start position:0% +regarding the Fourier transform from +last time after this point + + align:start position:0% + + + + align:start position:0% + +okay so let's do a counting lemma so + + align:start position:0% + + + + align:start position:0% + +what should a counting lemma say what + + align:start position:0% +what should a counting lemma say what + + + align:start position:0% +what should a counting lemma say what +the spirit of the counting lemma is that + + align:start position:0% +the spirit of the counting lemma is that + + + align:start position:0% +the spirit of the counting lemma is that +if you have two functions that are close + + align:start position:0% +if you have two functions that are close + + + align:start position:0% +if you have two functions that are close +to each other and how close means + + align:start position:0% +to each other and how close means + + + align:start position:0% +to each other and how close means +closing for you then their corresponding + + align:start position:0% +closing for you then their corresponding + + + align:start position:0% +closing for you then their corresponding +number of three peas should be similar + + align:start position:0% +number of three peas should be similar + + + align:start position:0% +number of three peas should be similar +so so that's what we want to say indeed + + align:start position:0% + + + + align:start position:0% + +so the County lemma for us will say that + + align:start position:0% +so the County lemma for us will say that + + + align:start position:0% +so the County lemma for us will say that +if F and G are functions on Z and such + + align:start position:0% +if F and G are functions on Z and such + + + align:start position:0% +if F and G are functions on Z and such +that they're l2 norms are both bounded + + align:start position:0% + + + + align:start position:0% + +by this M sum of the squared absolute + + align:start position:0% +by this M sum of the squared absolute + + + align:start position:0% +by this M sum of the squared absolute +value entries are both bounded then the + + align:start position:0% +value entries are both bounded then the + + + align:start position:0% +value entries are both bounded then the +difference of their three applicants + + align:start position:0% +difference of their three applicants + + + align:start position:0% +difference of their three applicants +should not be so different from each + + align:start position:0% +should not be so different from each + + + align:start position:0% +should not be so different from each +other if F and G are closing for you and + + align:start position:0% +other if F and G are closing for you and + + + align:start position:0% +other if F and G are closing for you and +that means if all the Fourier + + align:start position:0% +that means if all the Fourier + + + align:start position:0% +that means if all the Fourier +coefficients of F minus G are small then + + align:start position:0% +coefficients of F minus G are small then + + + align:start position:0% +coefficients of F minus G are small then +lambda 3 FF which considers three AP + + align:start position:0% +lambda 3 FF which considers three AP + + + align:start position:0% +lambda 3 FF which considers three AP +counting F is close to that of G okay + + align:start position:0% +counting F is close to that of G okay + + + align:start position:0% +counting F is close to that of G okay +same kind of three AP counting lama from + + align:start position:0% +same kind of three AP counting lama from + + + align:start position:0% +same kind of three AP counting lama from +last time so let's prove it as with + + align:start position:0% +last time so let's prove it as with + + + align:start position:0% +last time so let's prove it as with +accounting lemma proofs you've seen + + align:start position:0% +accounting lemma proofs you've seen + + + align:start position:0% +accounting lemma proofs you've seen +several times already in this course we + + align:start position:0% +several times already in this course we + + + align:start position:0% +several times already in this course we +will prove it by first writing this + + align:start position:0% +will prove it by first writing this + + + align:start position:0% +will prove it by first writing this +difference as a telescoping sum the + + align:start position:0% +difference as a telescoping sum the + + + align:start position:0% +difference as a telescoping sum the +first term being F minus G F and then G + + align:start position:0% +first term being F minus G F and then G + + + align:start position:0% +first term being F minus G F and then G +of F minus G F the lambda G G minus G + + align:start position:0% +of F minus G F the lambda G G minus G + + + align:start position:0% +of F minus G F the lambda G G minus G +and we would like to show that each of + + align:start position:0% +and we would like to show that each of + + + align:start position:0% +and we would like to show that each of +these terms is small if F minus G has + + align:start position:0% +these terms is small if F minus G has + + + align:start position:0% +these terms is small if F minus G has +small fourier coefficients so let's + + align:start position:0% +small fourier coefficients so let's + + + align:start position:0% +small fourier coefficients so let's +found the first term so let me bound + + align:start position:0% +found the first term so let me bound + + + align:start position:0% +found the first term so let me bound +this first term using the 3 AP identity + + align:start position:0% +this first term using the 3 AP identity + + + align:start position:0% +this first term using the 3 AP identity +relating through AP to Fourier + + align:start position:0% +relating through AP to Fourier + + + align:start position:0% +relating through AP to Fourier +coefficients we can write this lambda as + + align:start position:0% +coefficients we can write this lambda as + + + align:start position:0% +coefficients we can write this lambda as +the following integral over Fourier + + align:start position:0% +the following integral over Fourier + + + align:start position:0% +the following integral over Fourier +coefficients + + align:start position:0% + + + + align:start position:0% + +and now let me okay so what was the + + align:start position:0% +and now let me okay so what was the + + + align:start position:0% +and now let me okay so what was the +trick last time so we said let's pull + + align:start position:0% +trick last time so we said let's pull + + + align:start position:0% +trick last time so we said let's pull +out one of these guys and then use + + align:start position:0% +out one of these guys and then use + + + align:start position:0% +out one of these guys and then use +triangle inequality on the remaining + + align:start position:0% +triangle inequality on the remaining + + + align:start position:0% +triangle inequality on the remaining +factors so we'll do that so far so good + + align:start position:0% +factors so we'll do that so far so good + + + align:start position:0% +factors so we'll do that so far so good +and now you see this integral by Cauchy + + align:start position:0% +and now you see this integral by Cauchy + + + align:start position:0% +and now you see this integral by Cauchy +Schwarz Cauchy Schwarz the fast first + + align:start position:0% +Schwarz Cauchy Schwarz the fast first + + + align:start position:0% +Schwarz Cauchy Schwarz the fast first +factor you got this L to sum this L to + + align:start position:0% +factor you got this L to sum this L to + + + align:start position:0% +factor you got this L to sum this L to +integral and then you apply Cauchy + + align:start position:0% +integral and then you apply Cauchy + + + align:start position:0% +integral and then you apply Cauchy +Schwarz to the second factor now what do + + align:start position:0% +Schwarz to the second factor now what do + + + align:start position:0% +Schwarz to the second factor now what do +we do + + align:start position:0% + + + + align:start position:0% + +okay so yeah so you see in l2 or Fourier + + align:start position:0% +okay so yeah so you see in l2 or Fourier + + + align:start position:0% +okay so yeah so you see in l2 or Fourier +the first automatic reaction should be + + align:start position:0% +the first automatic reaction should be + + + align:start position:0% +the first automatic reaction should be +to use plan Tyrell or Percival so apply + + align:start position:0% +to use plan Tyrell or Percival so apply + + + align:start position:0% +to use plan Tyrell or Percival so apply +apply plan to RL identity to each of + + align:start position:0% +apply plan to RL identity to each of + + + align:start position:0% +apply plan to RL identity to each of +these factors we find that each of those + + align:start position:0% +these factors we find that each of those + + + align:start position:0% +these factors we find that each of those +factors is equal to this L to some in + + align:start position:0% +factors is equal to this L to some in + + + align:start position:0% +factors is equal to this L to some in +the physical space this square root the + + align:start position:0% +the physical space this square root the + + + align:start position:0% +the physical space this square root the +same thing screwed again okay and then + + align:start position:0% +same thing screwed again okay and then + + + align:start position:0% +same thing screwed again okay and then +we find that because there was a + + align:start position:0% +we find that because there was a + + + align:start position:0% +we find that because there was a +hypothesis in the hypothesis towards a + + align:start position:0% +hypothesis in the hypothesis towards a + + + align:start position:0% +hypothesis in the hypothesis towards a +pound and on this the sum of squares and + + align:start position:0% +pound and on this the sum of squares and + + + align:start position:0% +pound and on this the sum of squares and +similarly with the other two terms okay + + align:start position:0% +similarly with the other two terms okay + + + align:start position:0% +similarly with the other two terms okay +so that proves the county memo + + align:start position:0% + + + + align:start position:0% + +okay great + + align:start position:0% +okay great + + + align:start position:0% +okay great +so the question its last time we had a + + align:start position:0% +so the question its last time we had a + + + align:start position:0% +so the question its last time we had a +counting lemma that looked slightly + + align:start position:0% +counting lemma that looked slightly + + + align:start position:0% +counting lemma that looked slightly +different but I claimed they're all + + align:start position:0% +different but I claimed they're all + + + align:start position:0% +different but I claimed they're all +really the same counting lemma they're + + align:start position:0% +really the same counting lemma they're + + + align:start position:0% +really the same counting lemma they're +all the same proofs if you run this + + align:start position:0% +all the same proofs if you run this + + + align:start position:0% +all the same proofs if you run this +proof it won't work if you take what we + + align:start position:0% +proof it won't work if you take what we + + + align:start position:0% +proof it won't work if you take what we +did last time it's the same kind of + + align:start position:0% +did last time it's the same kind of + + + align:start position:0% +did last time it's the same kind of +proofs so last time we had a counting + + align:start position:0% +proofs so last time we had a counting + + + align:start position:0% +proofs so last time we had a counting +number where we had the same FF + + align:start position:0% +number where we had the same FF + + + align:start position:0% +number where we had the same FF +essentially well now I have allow you to + + align:start position:0% +essentially well now I have allow you to + + + align:start position:0% +essentially well now I have allow you to +essentially take three different things + + align:start position:0% +essentially take three different things + + + align:start position:0% +essentially take three different things +and okay so both in both cases you're + + align:start position:0% +and okay so both in both cases you're + + + align:start position:0% +and okay so both in both cases you're +running through this calculation but + + align:start position:0% +running through this calculation but + + + align:start position:0% +running through this calculation but +they look slightly different I agree it + + align:start position:0% +they look slightly different I agree it + + + align:start position:0% +they look slightly different I agree it +doesn't look exactly the same but if you + + align:start position:0% +doesn't look exactly the same but if you + + + align:start position:0% +doesn't look exactly the same but if you +think about what's involved in the proof + + align:start position:0% +think about what's involved in the proof + + + align:start position:0% +think about what's involved in the proof +they're the same proofs any more + + align:start position:0% +they're the same proofs any more + + + align:start position:0% +they're the same proofs any more +questions all right so now we have this + + align:start position:0% +questions all right so now we have this + + + align:start position:0% +questions all right so now we have this +County lemma so let's start our proof of + + align:start position:0% +County lemma so let's start our proof of + + + align:start position:0% +County lemma so let's start our proof of +Roth's theorem in the integers as with + + align:start position:0% +Roth's theorem in the integers as with + + + align:start position:0% +Roth's theorem in the integers as with +last time there will be three steps as + + align:start position:0% +last time there will be three steps as + + + align:start position:0% +last time there will be three steps as +mentioned up there okay in the first + + align:start position:0% +mentioned up there okay in the first + + + align:start position:0% +mentioned up there okay in the first +step + + align:start position:0% +step + + + align:start position:0% +step +let us show that if you are three AP + + align:start position:0% +let us show that if you are three AP + + + align:start position:0% +let us show that if you are three AP +free then we can obtain a density a + + align:start position:0% +free then we can obtain a density a + + + align:start position:0% +free then we can obtain a density a +large Fourier coefficient + + align:start position:0% + + + + align:start position:0% + +so in this course it's this counting + + align:start position:0% +so in this course it's this counting + + + align:start position:0% +so in this course it's this counting +number we actually saw just basically + + align:start position:0% +number we actually saw just basically + + + align:start position:0% +number we actually saw just basically +this kind of proof for the first time + + align:start position:0% +this kind of proof for the first time + + + align:start position:0% +this kind of proof for the first time +when we discussed graph counting lemma + + align:start position:0% +when we discussed graph counting lemma + + + align:start position:0% +when we discussed graph counting lemma +back in the chapter on samurai deist + + align:start position:0% +back in the chapter on samurai deist + + + align:start position:0% +back in the chapter on samurai deist +regularity lemma and sure they all look + + align:start position:0% +regularity lemma and sure they all look + + + align:start position:0% +regularity lemma and sure they all look +literally not exactly the same but + + align:start position:0% +literally not exactly the same but + + + align:start position:0% +literally not exactly the same but +they're all really the same kind of + + align:start position:0% +they're all really the same kind of + + + align:start position:0% +they're all really the same kind of +proofs I'm showing you the same thing in + + align:start position:0% +proofs I'm showing you the same thing in + + + align:start position:0% +proofs I'm showing you the same thing in +many different guises but they're all + + align:start position:0% +many different guises but they're all + + + align:start position:0% +many different guises but they're all +the same proofs so if you are a set free + + align:start position:0% + + + + align:start position:0% + +I'm ice with last time I'm going to call + + align:start position:0% +I'm ice with last time I'm going to call + + + align:start position:0% +I'm ice with last time I'm going to call +alpha the density of a now inside this + + align:start position:0% +alpha the density of a now inside this + + + align:start position:0% +alpha the density of a now inside this +progression this length end progression + + align:start position:0% +progression this length end progression + + + align:start position:0% +progression this length end progression +and suppose n is large enough so the + + align:start position:0% +and suppose n is large enough so the + + + align:start position:0% +and suppose n is large enough so the +conclusion now is that there exists some + + align:start position:0% +conclusion now is that there exists some + + + align:start position:0% +conclusion now is that there exists some +theta such that if you look at this sum + + align:start position:0% +theta such that if you look at this sum + + + align:start position:0% +theta such that if you look at this sum +over here as I sum over both integers + + align:start position:0% +over here as I sum over both integers + + + align:start position:0% +over here as I sum over both integers +actually I mean do the sum only from one + + align:start position:0% +actually I mean do the sum only from one + + + align:start position:0% +actually I mean do the sum only from one +to uppercase n I claim that it's saying + + align:start position:0% +to uppercase n I claim that it's saying + + + align:start position:0% +to uppercase n I claim that it's saying +what this title says if you are 383 and + + align:start position:0% +what this title says if you are 383 and + + + align:start position:0% +what this title says if you are 383 and +this end is large enough relative to the + + align:start position:0% +this end is large enough relative to the + + + align:start position:0% +this end is large enough relative to the +density you think of this density alpha + + align:start position:0% +density you think of this density alpha + + + align:start position:0% +density you think of this density alpha +is a constant then I can find a large + + align:start position:0% +is a constant then I can find a large + + + align:start position:0% +is a constant then I can find a large +Fourier coefficient you know there's a + + align:start position:0% +Fourier coefficient you know there's a + + + align:start position:0% +Fourier coefficient you know there's a +small difference and this is related to + + align:start position:0% +small difference and this is related to + + + align:start position:0% +small difference and this is related to +what you were asking earlier between how + + align:start position:0% +what you were asking earlier between how + + + align:start position:0% +what you were asking earlier between how +we set things up now versus will happen + + align:start position:0% +we set things up now versus will happen + + + align:start position:0% +we set things up now versus will happen +last time so last time we just look + + align:start position:0% +last time so last time we just look + + + align:start position:0% +last time so last time we just look +for a Fourier coefficient corresponding + + align:start position:0% +for a Fourier coefficient corresponding + + + align:start position:0% +for a Fourier coefficient corresponding +in tune non zero are now I'm not + + align:start position:0% +in tune non zero are now I'm not + + + align:start position:0% +in tune non zero are now I'm not +restricting non zero but I don't start + + align:start position:0% +restricting non zero but I don't start + + + align:start position:0% +restricting non zero but I don't start +with an indicator function I start with + + align:start position:0% +with an indicator function I start with + + + align:start position:0% +with an indicator function I start with +the demeaned indicator function I take + + align:start position:0% +the demeaned indicator function I take + + + align:start position:0% +the demeaned indicator function I take +out a me so that the zeroth coefficient + + align:start position:0% +out a me so that the zeroth coefficient + + + align:start position:0% +out a me so that the zeroth coefficient +so to speak which corresponds to the + + align:start position:0% +so to speak which corresponds to the + + + align:start position:0% +so to speak which corresponds to the +mean is already zero so you don't get to + + align:start position:0% +mean is already zero so you don't get to + + + align:start position:0% +mean is already zero so you don't get to +use that for your coefficient so if you + + align:start position:0% +use that for your coefficient so if you + + + align:start position:0% +use that for your coefficient so if you +didn't do this if you just try to do + + align:start position:0% +didn't do this if you just try to do + + + align:start position:0% +didn't do this if you just try to do +this last time and you can also do the + + align:start position:0% +this last time and you can also do the + + + align:start position:0% +this last time and you can also do the +exactly the same setup but if you don't + + align:start position:0% +exactly the same setup but if you don't + + + align:start position:0% +exactly the same setup but if you don't +be mean it then if you don't have this + + align:start position:0% +be mean it then if you don't have this + + + align:start position:0% +be mean it then if you don't have this +term then this statement is trivially + + align:start position:0% +term then this statement is trivially + + + align:start position:0% +term then this statement is trivially +true because I can take theta equal to + + align:start position:0% +true because I can take theta equal to + + + align:start position:0% +true because I can take theta equal to +zero that's but I don't want I want to I + + align:start position:0% +zero that's but I don't want I want to I + + + align:start position:0% +zero that's but I don't want I want to I +want an actual significant Fourier + + align:start position:0% +want an actual significant Fourier + + + align:start position:0% +want an actual significant Fourier +improvement so I take I do this demean + + align:start position:0% +improvement so I take I do this demean + + + align:start position:0% +improvement so I take I do this demean +and then I consider its Fourier + + align:start position:0% +and then I consider its Fourier + + + align:start position:0% +and then I consider its Fourier +coefficient okay any questions about the + + align:start position:0% +coefficient okay any questions about the + + + align:start position:0% +coefficient okay any questions about the +statement yeah so this demeaning is + + align:start position:0% +statement yeah so this demeaning is + + + align:start position:0% +statement yeah so this demeaning is +really important alright so that's + + align:start position:0% +really important alright so that's + + + align:start position:0% +really important alright so that's +something that's a very common technique + + align:start position:0% +something that's a very common technique + + + align:start position:0% +something that's a very common technique +whenever you do these kinds of analyses + + align:start position:0% +whenever you do these kinds of analyses + + + align:start position:0% +whenever you do these kinds of analyses +let's make sure you're okay so that + + align:start position:0% +let's make sure you're okay so that + + + align:start position:0% +let's make sure you're okay so that +you're so you're looking at functions + + align:start position:0% +you're so you're looking at functions + + + align:start position:0% +you're so you're looking at functions +with mean zero we have the following + + align:start position:0% + + + + align:start position:0% + +information about 3p counts in a because + + align:start position:0% +information about 3p counts in a because + + + align:start position:0% +information about 3p counts in a because +a is 3 P 3 so what is the value of + + align:start position:0% +a is 3 P 3 so what is the value of + + + align:start position:0% +a is 3 P 3 so what is the value of +lambda sub 3 of the indicator of a + + align:start position:0% + + + + align:start position:0% + +lambda of three if you look at the + + align:start position:0% +lambda of three if you look at the + + + align:start position:0% +lambda of three if you look at the +expression it basically sums over all 3 + + align:start position:0% +expression it basically sums over all 3 + + + align:start position:0% +expression it basically sums over all 3 +a piece but a has no 3 a piece except + + align:start position:0% +a piece but a has no 3 a piece except + + + align:start position:0% +a piece but a has no 3 a piece except +for the trivial ones so you only + + align:start position:0% +for the trivial ones so you only + + + align:start position:0% +for the trivial ones so you only +consider the trivial 3 a piece which has + + align:start position:0% +consider the trivial 3 a piece which has + + + align:start position:0% +consider the trivial 3 a piece which has +size exactly the size of a which is + + align:start position:0% +size exactly the size of a which is + + + align:start position:0% +size exactly the size of a which is +alpha N from trivial + + align:start position:0% +alpha N from trivial + + + align:start position:0% +alpha N from trivial +3a please on the other hand what do we + + align:start position:0% +3a please on the other hand what do we + + + align:start position:0% +3a please on the other hand what do we +know about lambda 3 of this interval + + align:start position:0% +know about lambda 3 of this interval + + + align:start position:0% +know about lambda 3 of this interval +from 1 to n ok so how many 3 a piece are + + align:start position:0% +from 1 to n ok so how many 3 a piece are + + + align:start position:0% +from 1 to n ok so how many 3 a piece are +there roughly it's going to be about N + + align:start position:0% +there roughly it's going to be about N + + + align:start position:0% +there roughly it's going to be about N +squared over 2 at least n squared over 2 + + align:start position:0% +squared over 2 at least n squared over 2 + + + align:start position:0% +squared over 2 at least n squared over 2 +because to generate a 3 AP I just have + + align:start position:0% +because to generate a 3 AP I just have + + + align:start position:0% +because to generate a 3 AP I just have +to pick a first term and the third term + + align:start position:0% +to pick a first term and the third term + + + align:start position:0% +to pick a first term and the third term +and I'm okay as long as they're the same + + align:start position:0% +and I'm okay as long as they're the same + + + align:start position:0% +and I'm okay as long as they're the same +parity then you have a 3 so same parity + + align:start position:0% +parity then you have a 3 so same parity + + + align:start position:0% +parity then you have a 3 so same parity +cuts you down by half so you have at + + align:start position:0% +cuts you down by half so you have at + + + align:start position:0% +cuts you down by half so you have at +least n squared over 2 3 a piece so now + + align:start position:0% +least n squared over 2 3 a piece so now + + + align:start position:0% +least n squared over 2 3 a piece so now +let's look at how to apply the counting + + align:start position:0% +let's look at how to apply the counting + + + align:start position:0% +let's look at how to apply the counting +lemma to this setting so we have the + + align:start position:0% +lemma to this setting so we have the + + + align:start position:0% +lemma to this setting so we have the +counting lemma up there where I now want + + align:start position:0% +counting lemma up there where I now want + + + align:start position:0% +counting lemma up there where I now want +to apply it so apply counting to on one + + align:start position:0% +to apply it so apply counting to on one + + + align:start position:0% +to apply it so apply counting to on one +hand the indicator function of a so so + + align:start position:0% +hand the indicator function of a so so + + + align:start position:0% +hand the indicator function of a so so +we get a count 3 piecing a but also + + align:start position:0% +we get a count 3 piecing a but also + + + align:start position:0% +we get a count 3 piecing a but also +compared to the normalized indicator on + + align:start position:0% +compared to the normalized indicator on + + + align:start position:0% +compared to the normalized indicator on +the interval okay so maybe this is a + + align:start position:0% +the interval okay so maybe this is a + + + align:start position:0% +the interval okay so maybe this is a +good point for me to pause and remind + + align:start position:0% +good point for me to pause and remind + + + align:start position:0% +good point for me to pause and remind +you that the spirit of this whole proof + + align:start position:0% +you that the spirit of this whole proof + + + align:start position:0% +you that the spirit of this whole proof +is understanding structure versus pseudo + + align:start position:0% +is understanding structure versus pseudo + + + align:start position:0% +is understanding structure versus pseudo +randomness as was was with the case last + + align:start position:0% +randomness as was was with the case last + + + align:start position:0% +randomness as was was with the case last +time so we want to understand in what + + align:start position:0% +time so we want to understand in what + + + align:start position:0% +time so we want to understand in what +ways is a pseudo random and here pseudo + + align:start position:0% +ways is a pseudo random and here pseudo + + + align:start position:0% +ways is a pseudo random and here pseudo +random just as what last time means + + align:start position:0% +random just as what last time means + + + align:start position:0% +random just as what last time means +having small Fourier coefficients being + + align:start position:0% +having small Fourier coefficients being + + + align:start position:0% +having small Fourier coefficients being +for a uniform if a pseudo random which + + align:start position:0% +for a uniform if a pseudo random which + + + align:start position:0% +for a uniform if a pseudo random which +here means F and G are close to each + + align:start position:0% +here means F and G are close to each + + + align:start position:0% +here means F and G are close to each +other that's what being school rehna + + align:start position:0% +other that's what being school rehna + + + align:start position:0% +other that's what being school rehna +means then the county line I will tell + + align:start position:0% +means then the county line I will tell + + + align:start position:0% +means then the county line I will tell +us the F and G should have + + align:start position:0% +us the F and G should have + + + align:start position:0% +us the F and G should have +a peek house but a has basically no AP + + align:start position:0% +a peek house but a has basically no AP + + + align:start position:0% +a peek house but a has basically no AP +account so they should not be close to + + align:start position:0% +account so they should not be close to + + + align:start position:0% +account so they should not be close to +each other so so that's right so that's + + align:start position:0% +each other so so that's right so that's + + + align:start position:0% +each other so so that's right so that's +the strategy to show that a is not + + align:start position:0% +the strategy to show that a is not + + + align:start position:0% +the strategy to show that a is not +pseudo-random in this sense and thereby + + align:start position:0% +pseudo-random in this sense and thereby + + + align:start position:0% +pseudo-random in this sense and thereby +extracting a large Fourier coefficient + + align:start position:0% +extracting a large Fourier coefficient + + + align:start position:0% +extracting a large Fourier coefficient +so we apply counting to these two + + align:start position:0% +so we apply counting to these two + + + align:start position:0% +so we apply counting to these two +functions and we obtain that so this + + align:start position:0% +functions and we obtain that so this + + + align:start position:0% +functions and we obtain that so this +quantity which corresponds to lambda 3 + + align:start position:0% +quantity which corresponds to lambda 3 + + + align:start position:0% +quantity which corresponds to lambda 3 +of G minus alpha n difference is upper + + align:start position:0% +of G minus alpha n difference is upper + + + align:start position:0% +of G minus alpha n difference is upper +bounded by the using the counting lemma + + align:start position:0% +bounded by the using the counting lemma + + + align:start position:0% +bounded by the using the counting lemma +we find that their difference is upper + + align:start position:0% +we find that their difference is upper + + + align:start position:0% +we find that their difference is upper +bounded by the following quantity + + align:start position:0% + + + + align:start position:0% + +namely you look at the difference + + align:start position:0% +namely you look at the difference + + + align:start position:0% +namely you look at the difference +between F and G and evaluate us maximum + + align:start position:0% +between F and G and evaluate us maximum + + + align:start position:0% +between F and G and evaluate us maximum +Fourier coefficient so if a is + + align:start position:0% +Fourier coefficient so if a is + + + align:start position:0% +Fourier coefficient so if a is +pseudo-random meaning that for a uniform + + align:start position:0% +pseudo-random meaning that for a uniform + + + align:start position:0% +pseudo-random meaning that for a uniform +this L infinity norm is small then I + + align:start position:0% +this L infinity norm is small then I + + + align:start position:0% +this L infinity norm is small then I +should expect lots and lots of 3a + + align:start position:0% +should expect lots and lots of 3a + + + align:start position:0% +should expect lots and lots of 3a +piecing it but because that is not the + + align:start position:0% +piecing it but because that is not the + + + align:start position:0% +piecing it but because that is not the +case we should be able to conclude that + + align:start position:0% +case we should be able to conclude that + + + align:start position:0% +case we should be able to conclude that +there is some large Fourier coefficient + + align:start position:0% + + + + align:start position:0% + +so thus rearranging the equation above + + align:start position:0% +so thus rearranging the equation above + + + align:start position:0% +so thus rearranging the equation above +we have that ok so we have this + + align:start position:0% +we have that ok so we have this + + + align:start position:0% +we have that ok so we have this +expression here and now we are ok so let + + align:start position:0% +expression here and now we are ok so let + + + align:start position:0% +expression here and now we are ok so let +me simplify this expression slightly and + + align:start position:0% +me simplify this expression slightly and + + + align:start position:0% +me simplify this expression slightly and +now we're using that and it's + + align:start position:0% +now we're using that and it's + + + align:start position:0% +now we're using that and it's +sufficiently large so where n is + + align:start position:0% +sufficiently large so where n is + + + align:start position:0% +sufficiently large so where n is +sufficiently large so this quantity is + + align:start position:0% +sufficiently large so this quantity is + + + align:start position:0% +sufficiently large so this quantity is +at least a tenth of alpha squared n and + + align:start position:0% +at least a tenth of alpha squared n and + + + align:start position:0% +at least a tenth of alpha squared n and +that's the conclusion all right so + + align:start position:0% +that's the conclusion all right so + + + align:start position:0% +that's the conclusion all right so +that's the conclusion of this step here + + align:start position:0% +that's the conclusion of this step here + + + align:start position:0% +that's the conclusion of this step here +what is this mean this means there + + align:start position:0% +what is this mean this means there + + + align:start position:0% +what is this mean this means there +exists some theta so that the Fourier + + align:start position:0% +exists some theta so that the Fourier + + + align:start position:0% +exists some theta so that the Fourier +coefficient at theta is at least the + + align:start position:0% +coefficient at theta is at least the + + + align:start position:0% +coefficient at theta is at least the +claimed quantity + + align:start position:0% + + + + align:start position:0% + +any questions so that finishes step one + + align:start position:0% +any questions so that finishes step one + + + align:start position:0% +any questions so that finishes step one +so now let me go on to step two in step + + align:start position:0% +so now let me go on to step two in step + + + align:start position:0% +so now let me go on to step two in step +two we wish to show that if you have a + + align:start position:0% +two we wish to show that if you have a + + + align:start position:0% +two we wish to show that if you have a +large for your coefficient then one can + + align:start position:0% +large for your coefficient then one can + + + align:start position:0% +large for your coefficient then one can +obtain a density increment so last time + + align:start position:0% +obtain a density increment so last time + + + align:start position:0% +obtain a density increment so last time +we were working in a finite field vector + + align:start position:0% +we were working in a finite field vector + + + align:start position:0% +we were working in a finite field vector +space a fourier coefficient which is a + + align:start position:0% +space a fourier coefficient which is a + + + align:start position:0% +space a fourier coefficient which is a +dual vector corresponds to some + + align:start position:0% +dual vector corresponds to some + + + align:start position:0% +dual vector corresponds to some +hyperplane and having a large fourier + + align:start position:0% +hyperplane and having a large fourier + + + align:start position:0% +hyperplane and having a large fourier +coefficient then implies that the + + align:start position:0% +coefficient then implies that the + + + align:start position:0% +coefficient then implies that the +density of a on the co set of those + + align:start position:0% +density of a on the co set of those + + + align:start position:0% +density of a on the co set of those +hyper planes must be not all close to + + align:start position:0% +hyper planes must be not all close to + + + align:start position:0% +hyper planes must be not all close to +each other so one of the hyper planes + + align:start position:0% +each other so one of the hyper planes + + + align:start position:0% +each other so one of the hyper planes +must have significantly higher density + + align:start position:0% +must have significantly higher density + + + align:start position:0% +must have significantly higher density +than the rest okay so we want to do + + align:start position:0% +than the rest okay so we want to do + + + align:start position:0% +than the rest okay so we want to do +something similar here except we run + + align:start position:0% +something similar here except we run + + + align:start position:0% +something similar here except we run +into this technical difficulty where + + align:start position:0% +into this technical difficulty where + + + align:start position:0% +into this technical difficulty where +there are no subspaces anymore right so + + align:start position:0% +there are no subspaces anymore right so + + + align:start position:0% +there are no subspaces anymore right so +the Fourier character namely + + align:start position:0% +the Fourier character namely + + + align:start position:0% +the Fourier character namely +corresponding to this theta is just a + + align:start position:0% +corresponding to this theta is just a + + + align:start position:0% +corresponding to this theta is just a +real number it doesn't divide up your + + align:start position:0% +real number it doesn't divide up your + + + align:start position:0% +real number it doesn't divide up your +space doesn't divide up you one two and + + align:start position:0% +space doesn't divide up you one two and + + + align:start position:0% +space doesn't divide up you one two and +very nice thing to sub chunks but we + + align:start position:0% +very nice thing to sub chunks but we + + + align:start position:0% +very nice thing to sub chunks but we +still want to use this data to chop up + + align:start position:0% +still want to use this data to chop up + + + align:start position:0% +still want to use this data to chop up +one to n into smaller spaces so that we + + align:start position:0% +one to n into smaller spaces so that we + + + align:start position:0% +one to n into smaller spaces so that we +can iterate and do density increment all + + align:start position:0% +can iterate and do density increment all + + + align:start position:0% +can iterate and do density increment all +right so let's see what we can do + + align:start position:0% +right so let's see what we can do + + + align:start position:0% +right so let's see what we can do +so given this data + + align:start position:0% + + + + align:start position:0% + +what we would like to do is to partition + + align:start position:0% + + + + align:start position:0% + +this one through n into sub progressions + + align:start position:0% + + + + align:start position:0% + +okay so chop up one to n into sub a + + align:start position:0% +okay so chop up one to n into sub a + + + align:start position:0% +okay so chop up one to n into sub a +piece such that if you evaluate so this + + align:start position:0% +piece such that if you evaluate so this + + + align:start position:0% +piece such that if you evaluate so this +data is fixed so on each sub ap this + + align:start position:0% +data is fixed so on each sub ap this + + + align:start position:0% +data is fixed so on each sub ap this +function here is roughly constant on + + align:start position:0% +function here is roughly constant on + + + align:start position:0% +function here is roughly constant on +each of your parts last time we had this + + align:start position:0% +each of your parts last time we had this + + + align:start position:0% +each of your parts last time we had this +for a character and then we chopped it + + align:start position:0% +for a character and then we chopped it + + + align:start position:0% +for a character and then we chopped it +up using these three hyperplanes + + align:start position:0% +up using these three hyperplanes + + + align:start position:0% +up using these three hyperplanes +and on each hyperplane the 48 character + + align:start position:0% +and on each hyperplane the 48 character + + + align:start position:0% +and on each hyperplane the 48 character +is literally constant that's what we + + align:start position:0% +is literally constant that's what we + + + align:start position:0% +is literally constant that's what we +worked with and now you cannot get them + + align:start position:0% +worked with and now you cannot get them + + + align:start position:0% +worked with and now you cannot get them +to be exactly constant but the next best + + align:start position:0% +to be exactly constant but the next best + + + align:start position:0% +to be exactly constant but the next best +thing we can hope for is to get this + + align:start position:0% +thing we can hope for is to get this + + + align:start position:0% +thing we can hope for is to get this +fourier character to be roughly constant + + align:start position:0% +fourier character to be roughly constant + + + align:start position:0% +fourier character to be roughly constant +okay so we're going to do some + + align:start position:0% +okay so we're going to do some + + + align:start position:0% +okay so we're going to do some +partitioning that allows us to achieve + + align:start position:0% +partitioning that allows us to achieve + + + align:start position:0% +partitioning that allows us to achieve +this characteristic and let me give you + + align:start position:0% +this characteristic and let me give you + + + align:start position:0% +this characteristic and let me give you +some intuition about why this is true + + align:start position:0% +some intuition about why this is true + + + align:start position:0% +some intuition about why this is true +and this is not exactly a surprise in + + align:start position:0% +and this is not exactly a surprise in + + + align:start position:0% +and this is not exactly a surprise in +fact the intuition is just that if you + + align:start position:0% +fact the intuition is just that if you + + + align:start position:0% +fact the intuition is just that if you +look at what this function behaves like + + align:start position:0% + + + + align:start position:0% + +so what's going on here you are on the + + align:start position:0% +so what's going on here you are on the + + + align:start position:0% +so what's going on here you are on the +unit circle and you are jumping by theta + + align:start position:0% + + + + align:start position:0% + +so you just keep jumping by theta and so + + align:start position:0% +so you just keep jumping by theta and so + + + align:start position:0% +so you just keep jumping by theta and so +on and I want to show that I can chop up + + align:start position:0% +on and I want to show that I can chop up + + + align:start position:0% +on and I want to show that I can chop up +my progression into a bunch of almost + + align:start position:0% +my progression into a bunch of almost + + + align:start position:0% +my progression into a bunch of almost +periodic pieces where in each part + + align:start position:0% +periodic pieces where in each part + + + align:start position:0% +periodic pieces where in each part +I'm staying inside a small arc and so in + + align:start position:0% +I'm staying inside a small arc and so in + + + align:start position:0% +I'm staying inside a small arc and so in +the extreme case of this where it is + + align:start position:0% +the extreme case of this where it is + + + align:start position:0% +the extreme case of this where it is +very easy to see is if X is some + + align:start position:0% +very easy to see is if X is some + + + align:start position:0% +very easy to see is if X is some +rational number + + align:start position:0% +rational number + + + align:start position:0% +rational number +a overbeat with be fairly small then we + + align:start position:0% +a overbeat with be fairly small then we + + + align:start position:0% +a overbeat with be fairly small then we +can so then this character is actually + + align:start position:0% +can so then this character is actually + + + align:start position:0% +can so then this character is actually +constant a piece with common different + + align:start position:0% +constant a piece with common different + + + align:start position:0% +constant a piece with common different +speed + + align:start position:0% + + + + align:start position:0% + +I so theta theta thank you theta 2 pi + + align:start position:0% + + + + align:start position:0% + +if theta is some rational with some + + align:start position:0% +if theta is some rational with some + + + align:start position:0% +if theta is some rational with some +small denominator so then you are + + align:start position:0% +small denominator so then you are + + + align:start position:0% +small denominator so then you are +literally jumping in periodic steps on + + align:start position:0% +literally jumping in periodic steps on + + + align:start position:0% +literally jumping in periodic steps on +the unit circle so if you partition and + + align:start position:0% +the unit circle so if you partition and + + + align:start position:0% +the unit circle so if you partition and +according to the exact same periods you + + align:start position:0% +according to the exact same periods you + + + align:start position:0% +according to the exact same periods you +have you have that this character is + + align:start position:0% +have you have that this character is + + + align:start position:0% +have you have that this character is +exactly constant on each of your + + align:start position:0% +exactly constant on each of your + + + align:start position:0% +exactly constant on each of your +progressions now in general the theta + + align:start position:0% +progressions now in general the theta + + + align:start position:0% +progressions now in general the theta +you get out of that proof might not have + + align:start position:0% +you get out of that proof might not have + + + align:start position:0% +you get out of that proof might not have +this very nice form but we can at least + + align:start position:0% +this very nice form but we can at least + + + align:start position:0% +this very nice form but we can at least +approximately achieve the desired effect + + align:start position:0% + + + + align:start position:0% + +any questions + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% + + + + align:start position:0% + +okay so to achieve approximately girth + + align:start position:0% +okay so to achieve approximately girth + + + align:start position:0% +okay so to achieve approximately girth +desired effect what we'll do is to find + + align:start position:0% +desired effect what we'll do is to find + + + align:start position:0% +desired effect what we'll do is to find +something so that B times theta is not + + align:start position:0% +something so that B times theta is not + + + align:start position:0% +something so that B times theta is not +quite an integer but very close to an + + align:start position:0% +quite an integer but very close to an + + + align:start position:0% +quite an integer but very close to an +integer okay so this probably many of + + align:start position:0% +integer okay so this probably many of + + + align:start position:0% +integer okay so this probably many of +you seen before it's a classic + + align:start position:0% +you seen before it's a classic + + + align:start position:0% +you seen before it's a classic +pigeonhole type result so if you have + + align:start position:0% +pigeonhole type result so if you have + + + align:start position:0% +pigeonhole type result so if you have +think of a real number and a delta kind + + align:start position:0% +think of a real number and a delta kind + + + align:start position:0% +think of a real number and a delta kind +of a tolerance then there exists a + + align:start position:0% +of a tolerance then there exists a + + + align:start position:0% +of a tolerance then there exists a +positive integer T at most one over + + align:start position:0% +positive integer T at most one over + + + align:start position:0% +positive integer T at most one over +delta such that the times theta is very + + align:start position:0% +delta such that the times theta is very + + + align:start position:0% +delta such that the times theta is very +close to an integer so this norm here is + + align:start position:0% +close to an integer so this norm here is + + + align:start position:0% +close to an integer so this norm here is +distance to the closest integer + + align:start position:0% + + + + align:start position:0% + +alright alright so the proof here is by + + align:start position:0% +alright alright so the proof here is by + + + align:start position:0% +alright alright so the proof here is by +pigeonhole principle so if we let M be 1 + + align:start position:0% +pigeonhole principle so if we let M be 1 + + + align:start position:0% +pigeonhole principle so if we let M be 1 +over Delta round down and consider the + + align:start position:0% +over Delta round down and consider the + + + align:start position:0% +over Delta round down and consider the +numbers 0 theta 2 theta 3 data and so on + + align:start position:0% +numbers 0 theta 2 theta 3 data and so on + + + align:start position:0% +numbers 0 theta 2 theta 3 data and so on +- M theta so by pigeonhole there exists + + align:start position:0% +- M theta so by pigeonhole there exists + + + align:start position:0% +- M theta so by pigeonhole there exists +I theta J theta some two different terms + + align:start position:0% +I theta J theta some two different terms + + + align:start position:0% +I theta J theta some two different terms +of the sequence such that they differ by + + align:start position:0% +of the sequence such that they differ by + + + align:start position:0% +of the sequence such that they differ by +less than most Delta in their fractional + + align:start position:0% +less than most Delta in their fractional + + + align:start position:0% +less than most Delta in their fractional +parts so now I'll take T to be + + align:start position:0% +parts so now I'll take T to be + + + align:start position:0% +parts so now I'll take T to be +difference between I and J ok so even + + align:start position:0% +difference between I and J ok so even + + + align:start position:0% +difference between I and J ok so even +though you don't have exactly rational + + align:start position:0% +though you don't have exactly rational + + + align:start position:0% +though you don't have exactly rational +we have approximately ratio so this is a + + align:start position:0% +we have approximately ratio so this is a + + + align:start position:0% +we have approximately ratio so this is a +it's a simple rational approximation + + align:start position:0% +it's a simple rational approximation + + + align:start position:0% +it's a simple rational approximation +statement and using this operational + + align:start position:0% +statement and using this operational + + + align:start position:0% +statement and using this operational +approximation we can now kind of try to + + align:start position:0% +approximation we can now kind of try to + + + align:start position:0% +approximation we can now kind of try to +do the intuition here pretending that + + align:start position:0% +do the intuition here pretending that + + + align:start position:0% +do the intuition here pretending that +we're working with rational numbers so + + align:start position:0% +we're working with rational numbers so + + + align:start position:0% +we're working with rational numbers so +if we take a tie between 0 & 1 + + align:start position:0% + + + + align:start position:0% + +theta irrational and suppose and it's + + align:start position:0% +theta irrational and suppose and it's + + + align:start position:0% +theta irrational and suppose and it's +large enough okay so here C means there + + align:start position:0% +large enough okay so here C means there + + + align:start position:0% +large enough okay so here C means there +exist some sufficiently large some + + align:start position:0% +exist some sufficiently large some + + + align:start position:0% +exist some sufficiently large some +constant C such that the statement is + + align:start position:0% +constant C such that the statement is + + + align:start position:0% +constant C such that the statement is +true so suppose think million yeah that + + align:start position:0% +true so suppose think million yeah that + + + align:start position:0% +true so suppose think million yeah that +should be fine so then there exists so + + align:start position:0% +should be fine so then there exists so + + + align:start position:0% +should be fine so then there exists so +then one can partition one to n into sub + + align:start position:0% +then one can partition one to n into sub + + + align:start position:0% +then one can partition one to n into sub +ApS which will call P I and each having + + align:start position:0% +ApS which will call P I and each having + + + align:start position:0% +ApS which will call P I and each having +length between cube root of n and twice + + align:start position:0% +length between cube root of n and twice + + + align:start position:0% +length between cube root of n and twice +the cube root of n such that this + + align:start position:0% +the cube root of n such that this + + + align:start position:0% +the cube root of n such that this +character that we want to stay roughly + + align:start position:0% +character that we want to stay roughly + + + align:start position:0% +character that we want to stay roughly +constant indeed does not change very + + align:start position:0% +constant indeed does not change very + + + align:start position:0% +constant indeed does not change very +much if you look at two terms in the + + align:start position:0% +much if you look at two terms in the + + + align:start position:0% +much if you look at two terms in the +same AP in the same sub AP then the + + align:start position:0% +same AP in the same sub AP then the + + + align:start position:0% +same AP in the same sub AP then the +value of this character each P sub I is + + align:start position:0% +value of this character each P sub I is + + + align:start position:0% +value of this character each P sub I is +roughly the same so they don't vary by + + align:start position:0% +roughly the same so they don't vary by + + + align:start position:0% +roughly the same so they don't vary by +more than Etta on each P I right so here + + align:start position:0% +more than Etta on each P I right so here + + + align:start position:0% +more than Etta on each P I right so here +we're partitioning this one to n into a + + align:start position:0% +we're partitioning this one to n into a + + + align:start position:0% +we're partitioning this one to n into a +sub a piece so that this guy here stays + + align:start position:0% +sub a piece so that this guy here stays + + + align:start position:0% +sub a piece so that this guy here stays +roughly constant + + align:start position:0% + + + + align:start position:0% + +okay any questions alright so think + + align:start position:0% +okay any questions alright so think + + + align:start position:0% +okay any questions alright so think +about how you might prove this let's + + align:start position:0% +about how you might prove this let's + + + align:start position:0% +about how you might prove this let's +take a quick break so you see we are + + align:start position:0% +take a quick break so you see we are + + + align:start position:0% +take a quick break so you see we are +basically following the same strategy as + + align:start position:0% +basically following the same strategy as + + + align:start position:0% +basically following the same strategy as +a proof from last time but this second + + align:start position:0% +a proof from last time but this second + + + align:start position:0% +a proof from last time but this second +step which we're all right now needs to + + align:start position:0% +step which we're all right now needs to + + + align:start position:0% +step which we're all right now needs to +be somewhat modified because you cannot + + align:start position:0% +be somewhat modified because you cannot + + + align:start position:0% +be somewhat modified because you cannot +cut this space up into pieces where your + + align:start position:0% +cut this space up into pieces where your + + + align:start position:0% +cut this space up into pieces where your +character is constant if they're roughly + + align:start position:0% +character is constant if they're roughly + + + align:start position:0% +character is constant if they're roughly +constant then we're good to go so that's + + align:start position:0% +constant then we're good to go so that's + + + align:start position:0% +constant then we're good to go so that's +what we're doing now so let's prove the + + align:start position:0% +what we're doing now so let's prove the + + + align:start position:0% +what we're doing now so let's prove the +statement up there so let's prove this + + align:start position:0% +statement up there so let's prove this + + + align:start position:0% +statement up there so let's prove this +statement over here + + align:start position:0% +statement over here + + + align:start position:0% +statement over here +so using we find that there exists some + + align:start position:0% +so using we find that there exists some + + + align:start position:0% +so using we find that there exists some +D okay so write down some number for now + + align:start position:0% +D okay so write down some number for now + + + align:start position:0% +D okay so write down some number for now +don't worry about any more come up short + + align:start position:0% +don't worry about any more come up short + + + align:start position:0% +don't worry about any more come up short +you why I write this specific quantity + + align:start position:0% +you why I write this specific quantity + + + align:start position:0% +you why I write this specific quantity +so there exist some D just not too big + + align:start position:0% +so there exist some D just not too big + + + align:start position:0% +so there exist some D just not too big +such that + + align:start position:0% + + + + align:start position:0% + +d theta is very close to an integer so + + align:start position:0% +d theta is very close to an integer so + + + align:start position:0% +d theta is very close to an integer so +now I'm merely applying for excellent + + align:start position:0% + + + + align:start position:0% + +okay so given such D and so how big is + + align:start position:0% +okay so given such D and so how big is + + + align:start position:0% +okay so given such D and so how big is +this T you see that because I assumed + + align:start position:0% +this T you see that because I assumed + + + align:start position:0% +this T you see that because I assumed +that n is sufficiently large if we + + align:start position:0% +that n is sufficiently large if we + + + align:start position:0% +that n is sufficiently large if we +choose that seed large enough T is at + + align:start position:0% +choose that seed large enough T is at + + + align:start position:0% +choose that seed large enough T is at +most root n so given such T which is at + + align:start position:0% +most root n so given such T which is at + + + align:start position:0% +most root n so given such T which is at +most root n you can partition 1 to n + + align:start position:0% +most root n you can partition 1 to n + + + align:start position:0% +most root n you can partition 1 to n +into sub progressions with common + + align:start position:0% +into sub progressions with common + + + align:start position:0% +into sub progressions with common +difference D essentially look at residue + + align:start position:0% +difference D essentially look at residue + + + align:start position:0% +difference D essentially look at residue +classes mod T so they're all going to + + align:start position:0% +classes mod T so they're all going to + + + align:start position:0% +classes mod T so they're all going to +have length by basically and over D and + + align:start position:0% +have length by basically and over D and + + + align:start position:0% +have length by basically and over D and +I chopped them up a little bit further + + align:start position:0% +I chopped them up a little bit further + + + align:start position:0% +I chopped them up a little bit further +to get so a piece of lengths between + + align:start position:0% +to get so a piece of lengths between + + + align:start position:0% +to get so a piece of lengths between +cube root of N and twice cube root of N + + align:start position:0% + + + + align:start position:0% + +so I'm going to make sure that all of my + + align:start position:0% +so I'm going to make sure that all of my + + + align:start position:0% +so I'm going to make sure that all of my +ApS are roughly the same length and now + + align:start position:0% +ApS are roughly the same length and now + + + align:start position:0% +ApS are roughly the same length and now +inside each sub progression let me call + + align:start position:0% +inside each sub progression let me call + + + align:start position:0% +inside each sub progression let me call +the sub progression P prime sub + + align:start position:0% +the sub progression P prime sub + + + align:start position:0% +the sub progression P prime sub +progression P let's look at how much + + align:start position:0% +progression P let's look at how much + + + align:start position:0% +progression P let's look at how much +this character value can vary inside + + align:start position:0% +this character value can vary inside + + + align:start position:0% +this character value can vary inside +this progression so we how much can this + + align:start position:0% +this progression so we how much can this + + + align:start position:0% +this progression so we how much can this +can this very well because theta is such + + align:start position:0% +can this very well because theta is such + + + align:start position:0% +can this very well because theta is such +that D times theta is very close to an + + align:start position:0% +that D times theta is very close to an + + + align:start position:0% +that D times theta is very close to an +integer and the length of each + + align:start position:0% +integer and the length of each + + + align:start position:0% +integer and the length of each +progression is not too large here I want + + align:start position:0% +progression is not too large here I want + + + align:start position:0% +progression is not too large here I want +some control on the length so we find + + align:start position:0% +some control on the length so we find + + + align:start position:0% +some control on the length so we find +that the maximum variation is at most + + align:start position:0% +that the maximum variation is at most + + + align:start position:0% +that the maximum variation is at most +the size of P the length of P times so + + align:start position:0% +the size of P the length of P times so + + + align:start position:0% +the size of P the length of P times so +this that difference over there all of + + align:start position:0% +this that difference over there all of + + + align:start position:0% +this that difference over there all of +these are exponential so I can shift + + align:start position:0% +these are exponential so I can shift + + + align:start position:0% +these are exponential so I can shift +them well the length of P is at most + + align:start position:0% +them well the length of P is at most + + + align:start position:0% +them well the length of P is at most +twice cube root of n and okay so what is + + align:start position:0% +twice cube root of n and okay so what is + + + align:start position:0% +twice cube root of n and okay so what is +this quantity so the point is that if + + align:start position:0% +this quantity so the point is that if + + + align:start position:0% +this quantity so the point is that if +this fractional part here is very close + + align:start position:0% +this fractional part here is very close + + + align:start position:0% +this fractional part here is very close +to an integer then e to that number you + + align:start position:0% +to an integer then e to that number you + + + align:start position:0% +to an integer then e to that number you +to the 2pi times that item number should + + align:start position:0% +to the 2pi times that item number should + + + align:start position:0% +to the 2pi times that item number should +be very close to one because what's + + align:start position:0% +be very close to one because what's + + + align:start position:0% +be very close to one because what's +happening here this is the distance + + align:start position:0% +happening here this is the distance + + + align:start position:0% +happening here this is the distance +between those two points on a circle + + align:start position:0% +between those two points on a circle + + + align:start position:0% +between those two points on a circle +which is and most bounded by the length + + align:start position:0% +which is and most bounded by the length + + + align:start position:0% +which is and most bounded by the length +of the arc + + align:start position:0% + + + + align:start position:0% + +okay so court length and most out of the + + align:start position:0% +okay so court length and most out of the + + + align:start position:0% +okay so court length and most out of the +arc so now you put everything here + + align:start position:0% +arc so now you put everything here + + + align:start position:0% +arc so now you put everything here +together and applying the bound that we + + align:start position:0% +together and applying the bound that we + + + align:start position:0% +together and applying the bound that we +got D theta so this is the reason for + + align:start position:0% +got D theta so this is the reason for + + + align:start position:0% +got D theta so this is the reason for +choosing that we are number up there we + + align:start position:0% +choosing that we are number up there we + + + align:start position:0% +choosing that we are number up there we +find that variation within each + + align:start position:0% +find that variation within each + + + align:start position:0% +find that variation within each +progression is at most eight so + + align:start position:0% +progression is at most eight so + + + align:start position:0% +progression is at most eight so +variation of this character within each + + align:start position:0% +variation of this character within each + + + align:start position:0% +variation of this character within each +progression it's not very large and that + + align:start position:0% +progression it's not very large and that + + + align:start position:0% +progression it's not very large and that +that's the claim any questions so this + + align:start position:0% +that's the claim any questions so this + + + align:start position:0% +that's the claim any questions so this +is the analogous claim to the one that + + align:start position:0% +is the analogous claim to the one that + + + align:start position:0% +is the analogous claim to the one that +we have the one that we used last time + + align:start position:0% +we have the one that we used last time + + + align:start position:0% +we have the one that we used last time +where we said that the character is + + align:start position:0% +where we said that the character is + + + align:start position:0% +where we said that the character is +constant on each cosine of the + + align:start position:0% +constant on each cosine of the + + + align:start position:0% +constant on each cosine of the +hyperplane not exactly constant but + + align:start position:0% +hyperplane not exactly constant but + + + align:start position:0% +hyperplane not exactly constant but +almost good enough + + align:start position:0% + + + + align:start position:0% + +all right so the goal of step two is to + + align:start position:0% +all right so the goal of step two is to + + + align:start position:0% +all right so the goal of step two is to +show an energy so a density increment + + align:start position:0% +show an energy so a density increment + + + align:start position:0% +show an energy so a density increment +that if you have a large Fourier + + align:start position:0% +that if you have a large Fourier + + + align:start position:0% +that if you have a large Fourier +coefficient then we want to claim that + + align:start position:0% +coefficient then we want to claim that + + + align:start position:0% +coefficient then we want to claim that +the density goes up significantly on + + align:start position:0% +the density goes up significantly on + + + align:start position:0% +the density goes up significantly on +some sub progression and the next part + + align:start position:0% +some sub progression and the next part + + + align:start position:0% +some sub progression and the next part +the next lemma will get us to that goal + + align:start position:0% +the next lemma will get us to that goal + + + align:start position:0% +the next lemma will get us to that goal +and this part is very similar to the one + + align:start position:0% +and this part is very similar to the one + + + align:start position:0% +and this part is very similar to the one +that we saw from last time but with this + + align:start position:0% +that we saw from last time but with this + + + align:start position:0% +that we saw from last time but with this +new partition in - density alpha and + + align:start position:0% + + + + align:start position:0% + +exist some progression sub progression I + + align:start position:0% +exist some progression sub progression I + + + align:start position:0% +exist some progression sub progression I +just mean that I'm starting with + + align:start position:0% +just mean that I'm starting with + + + align:start position:0% +just mean that I'm starting with +original progression 1 to N and I'm + + align:start position:0% +original progression 1 to N and I'm + + + align:start position:0% +original progression 1 to N and I'm +zooming in to some sub progression with + + align:start position:0% +zooming in to some sub progression with + + + align:start position:0% +zooming in to some sub progression with +the length of P fairly long so the + + align:start position:0% +the length of P fairly long so the + + + align:start position:0% +the length of P fairly long so the +length appears at least cube root of N + + align:start position:0% +length appears at least cube root of N + + + align:start position:0% +length appears at least cube root of N +and such that a when restricted to this + + align:start position:0% +and such that a when restricted to this + + + align:start position:0% +and such that a when restricted to this +sub progression has a density increment + + align:start position:0% + + + + align:start position:0% + +so originally the density of a is alpha + + align:start position:0% +so originally the density of a is alpha + + + align:start position:0% +so originally the density of a is alpha +so we're zooming into some sub + + align:start position:0% +so we're zooming into some sub + + + align:start position:0% +so we're zooming into some sub +progression P with a pretty long sub + + align:start position:0% +progression P with a pretty long sub + + + align:start position:0% +progression P with a pretty long sub +progression where the density goes up + + align:start position:0% +progression where the density goes up + + + align:start position:0% +progression where the density goes up +significantly from a to essentially a + + align:start position:0% +significantly from a to essentially a + + + align:start position:0% +significantly from a to essentially a +from alpha to roughly alpha plus alpha + + align:start position:0% +from alpha to roughly alpha plus alpha + + + align:start position:0% +from alpha to roughly alpha plus alpha +squared okay + + align:start position:0% + + + + align:start position:0% + +all right so we start with a 383 set so + + align:start position:0% +all right so we start with a 383 set so + + + align:start position:0% +all right so we start with a 383 set so +from step one there exists some data + + align:start position:0% +from step one there exists some data + + + align:start position:0% +from step one there exists some data +with large code so a corresponds to a + + align:start position:0% +with large code so a corresponds to a + + + align:start position:0% +with large code so a corresponds to a +large Fourier coefficient so this sum + + align:start position:0% +large Fourier coefficient so this sum + + + align:start position:0% +large Fourier coefficient so this sum +here + + align:start position:0% + + + + align:start position:0% + +and now we use okay so step one this + + align:start position:0% +and now we use okay so step one this + + + align:start position:0% +and now we use okay so step one this +consequence and from this data now we + + align:start position:0% +consequence and from this data now we + + + align:start position:0% +consequence and from this data now we +apply the lemma up there too so we apply + + align:start position:0% +apply the lemma up there too so we apply + + + align:start position:0% +apply the lemma up there too so we apply +lemma where let's say ha being alpha + + align:start position:0% +lemma where let's say ha being alpha + + + align:start position:0% +lemma where let's say ha being alpha +squared over 30 the exact constants are + + align:start position:0% +squared over 30 the exact constants are + + + align:start position:0% +squared over 30 the exact constants are +not so important when we apply the lemma + + align:start position:0% +not so important when we apply the lemma + + + align:start position:0% +not so important when we apply the lemma +to partition and into a bunch of sub + + align:start position:0% +to partition and into a bunch of sub + + + align:start position:0% +to partition and into a bunch of sub +progressions which we'll call p1 through + + align:start position:0% +progressions which we'll call p1 through + + + align:start position:0% +progressions which we'll call p1 through +p8 and each of these progressions have + + align:start position:0% +p8 and each of these progressions have + + + align:start position:0% +p8 and each of these progressions have +length between cube root of n and twice + + align:start position:0% + + + + align:start position:0% + +and I want to understand what happens to + + align:start position:0% +and I want to understand what happens to + + + align:start position:0% +and I want to understand what happens to +the density of a when restricted to + + align:start position:0% +the density of a when restricted to + + + align:start position:0% +the density of a when restricted to +these progressions so starting with this + + align:start position:0% +these progressions so starting with this + + + align:start position:0% +these progressions so starting with this +inequality over here which suggests to + + align:start position:0% +inequality over here which suggests to + + + align:start position:0% +inequality over here which suggests to +us that there must be some deviation so + + align:start position:0% +us that there must be some deviation so + + + align:start position:0% +us that there must be some deviation so +starting starting with what we saw and + + align:start position:0% +starting starting with what we saw and + + + align:start position:0% +starting starting with what we saw and +now inside each progression this the X + + align:start position:0% +now inside each progression this the X + + + align:start position:0% +now inside each progression this the X +theta is roughly constant so if you + + align:start position:0% +theta is roughly constant so if you + + + align:start position:0% +theta is roughly constant so if you +pretend them as actually constant I can + + align:start position:0% +pretend them as actually constant I can + + + align:start position:0% +pretend them as actually constant I can +break up this Sun depending on where the + + align:start position:0% +break up this Sun depending on where the + + + align:start position:0% +break up this Sun depending on where the +XS lie so I from 1 okay and let me sum + + align:start position:0% +XS lie so I from 1 okay and let me sum + + + align:start position:0% +XS lie so I from 1 okay and let me sum +inside each progression okay so by + + align:start position:0% +inside each progression okay so by + + + align:start position:0% +inside each progression okay so by +triangle inequality + + align:start position:0% +triangle inequality + + + align:start position:0% +triangle inequality +I can upper bound the first sum by where + + align:start position:0% +I can upper bound the first sum by where + + + align:start position:0% +I can upper bound the first sum by where +I now cut some into progression by + + align:start position:0% +I now cut some into progression by + + + align:start position:0% +I now cut some into progression by +progression and on each progression this + + align:start position:0% +progression and on each progression this + + + align:start position:0% +progression and on each progression this +character is roughly constant so let me + + align:start position:0% +character is roughly constant so let me + + + align:start position:0% +character is roughly constant so let me +take out the maximum possible deviations + + align:start position:0% +take out the maximum possible deviations + + + align:start position:0% +take out the maximum possible deviations +from them being constant so upper bound + + align:start position:0% +from them being constant so upper bound + + + align:start position:0% +from them being constant so upper bound +again you find that we can essentially + + align:start position:0% +again you find that we can essentially + + + align:start position:0% +again you find that we can essentially +pretend so if each exponential is + + align:start position:0% +pretend so if each exponential is + + + align:start position:0% +pretend so if each exponential is +constant on each sub progression then I + + align:start position:0% +constant on each sub progression then I + + + align:start position:0% +constant on each sub progression then I +- well just have this sum here but I + + align:start position:0% +- well just have this sum here but I + + + align:start position:0% +- well just have this sum here but I +lose a little bit because it's not + + align:start position:0% +lose a little bit because it's not + + + align:start position:0% +lose a little bit because it's not +exactly constants almost constant so I + + align:start position:0% +exactly constants almost constant so I + + + align:start position:0% +exactly constants almost constant so I +lose a little bit and that little bit is + + align:start position:0% +lose a little bit and that little bit is + + + align:start position:0% +lose a little bit and that little bit is +this + + align:start position:0% +this + + + align:start position:0% +this +lose that little bit of a tub and so on + + align:start position:0% +lose that little bit of a tub and so on + + + align:start position:0% +lose that little bit of a tub and so on +each progression P I you lose almost + + align:start position:0% +each progression P I you lose almost + + + align:start position:0% +each progression P I you lose almost +something that's essentially of a square + + align:start position:0% +something that's essentially of a square + + + align:start position:0% +something that's essentially of a square +times the length of P i okay now you see + + align:start position:0% +times the length of P i okay now you see + + + align:start position:0% +times the length of P i okay now you see +I've chosen the error parameter so that + + align:start position:0% +I've chosen the error parameter so that + + + align:start position:0% +I've chosen the error parameter so that +everything I've lost is no not so much + + align:start position:0% +everything I've lost is no not so much + + + align:start position:0% +everything I've lost is no not so much +more than the initial bound I began with + + align:start position:0% +more than the initial bound I began with + + + align:start position:0% +more than the initial bound I began with +so in particular we see that even if we + + align:start position:0% +so in particular we see that even if we + + + align:start position:0% +so in particular we see that even if we +have pretended that the characters were + + align:start position:0% +have pretended that the characters were + + + align:start position:0% +have pretended that the characters were +constant on each progression we would + + align:start position:0% +constant on each progression we would + + + align:start position:0% +constant on each progression we would +have still obtained some lower bound on + + align:start position:0% +have still obtained some lower bound on + + + align:start position:0% +have still obtained some lower bound on +the total deviation okay and what is + + align:start position:0% +the total deviation okay and what is + + + align:start position:0% +the total deviation okay and what is +this quantity over here or you see I'm + + align:start position:0% +this quantity over here or you see I'm + + + align:start position:0% +this quantity over here or you see I'm +restricting each some to each sub + + align:start position:0% +restricting each some to each sub + + + align:start position:0% +restricting each some to each sub +progression but this sum here even + + align:start position:0% +progression but this sum here even + + + align:start position:0% +progression but this sum here even +though it's the sum but it's really + + align:start position:0% +though it's the sum but it's really + + + align:start position:0% +though it's the sum but it's really +counting how many elements of a are in + + align:start position:0% +counting how many elements of a are in + + + align:start position:0% +counting how many elements of a are in +that progression so this sum over here + + align:start position:0% +that progression so this sum over here + + + align:start position:0% +that progression so this sum over here +is the same thing okay so let me write + + align:start position:0% +is the same thing okay so let me write + + + align:start position:0% +is the same thing okay so let me write +it Newport + + align:start position:0% + + + + align:start position:0% + +so so what we have so the left-hand side + + align:start position:0% +so so what we have so the left-hand side + + + align:start position:0% +so so what we have so the left-hand side +over there is this quantity here we see + + align:start position:0% +over there is this quantity here we see + + + align:start position:0% +over there is this quantity here we see +that the right-hand side even though you + + align:start position:0% +that the right-hand side even though you + + + align:start position:0% +that the right-hand side even though you +have that sum it is really just counting + + align:start position:0% +have that sum it is really just counting + + + align:start position:0% +have that sum it is really just counting +how many elements of a are in each + + align:start position:0% +how many elements of a are in each + + + align:start position:0% +how many elements of a are in each +progression versus how many you should + + align:start position:0% +progression versus how many you should + + + align:start position:0% +progression versus how many you should +expect based on the overall density of a + + align:start position:0% + + + + align:start position:0% + +so that should look similar to what we + + align:start position:0% +so that should look similar to what we + + + align:start position:0% +so that should look similar to what we +got last time I know the intuition + + align:start position:0% +got last time I know the intuition + + + align:start position:0% +got last time I know the intuition +should be that well if the average + + align:start position:0% +should be that well if the average + + + align:start position:0% +should be that well if the average +deviation is large then one of them one + + align:start position:0% +deviation is large then one of them one + + + align:start position:0% +deviation is large then one of them one +of these terms should have the density + + align:start position:0% +of these terms should have the density + + + align:start position:0% +of these terms should have the density +increment if you try to do the next step + + align:start position:0% +increment if you try to do the next step + + + align:start position:0% +increment if you try to do the next step +somewhat naively you run into an issue + + align:start position:0% +somewhat naively you run into an issue + + + align:start position:0% +somewhat naively you run into an issue +because it could be here you have K + + align:start position:0% +because it could be here you have K + + + align:start position:0% +because it could be here you have K +terms it could be that you have all the + + align:start position:0% +terms it could be that you have all the + + + align:start position:0% +terms it could be that you have all the +densities except for one going up only + + align:start position:0% +densities except for one going up only + + + align:start position:0% +densities except for one going up only +slightly and one density dropping + + align:start position:0% +slightly and one density dropping + + + align:start position:0% +slightly and one density dropping +dramatically in which case you might not + + align:start position:0% +dramatically in which case you might not + + + align:start position:0% +dramatically in which case you might not +have a significant density increment + + align:start position:0% +have a significant density increment + + + align:start position:0% +have a significant density increment +right so we want to show that on some + + align:start position:0% +right so we want to show that on some + + + align:start position:0% +right so we want to show that on some +progression the density increases + + align:start position:0% +progression the density increases + + + align:start position:0% +progression the density increases +significantly so far from this + + align:start position:0% +significantly so far from this + + + align:start position:0% +significantly so far from this +inequality we just know that there is + + align:start position:0% +inequality we just know that there is + + + align:start position:0% +inequality we just know that there is +some sub progression where the density + + align:start position:0% +some sub progression where the density + + + align:start position:0% +some sub progression where the density +changes significantly but of course the + + align:start position:0% +changes significantly but of course the + + + align:start position:0% +changes significantly but of course the +overall density the average density + + align:start position:0% +overall density the average density + + + align:start position:0% +overall density the average density +should remain constant so if some goes + + align:start position:0% +should remain constant so if some goes + + + align:start position:0% +should remain constant so if some goes +up others must go down but if you just + + align:start position:0% +up others must go down but if you just + + + align:start position:0% +up others must go down but if you just +try to do an averaging argument you have + + align:start position:0% +try to do an averaging argument you have + + + align:start position:0% +try to do an averaging argument you have +to be careful so so there was a trick + + align:start position:0% +to be careful so so there was a trick + + + align:start position:0% +to be careful so so there was a trick +last time which we didn't really mean + + align:start position:0% +last time which we didn't really mean + + + align:start position:0% +last time which we didn't really mean +last time but now now it's much more you + + align:start position:0% +last time but now now it's much more you + + + align:start position:0% +last time but now now it's much more you +more useful where I want to show that if + + align:start position:0% +more useful where I want to show that if + + + align:start position:0% +more useful where I want to show that if +this holds then some P I sees a large + + align:start position:0% +this holds then some P I sees a large + + + align:start position:0% +this holds then some P I sees a large +and it sees a large density increment + + align:start position:0% +and it sees a large density increment + + + align:start position:0% +and it sees a large density increment +and to do that let me rewrite this + + align:start position:0% + + + + align:start position:0% + +as the following so I keep the same + + align:start position:0% +as the following so I keep the same + + + align:start position:0% +as the following so I keep the same +expression and I add a term which is the + + align:start position:0% +expression and I add a term which is the + + + align:start position:0% +expression and I add a term which is the +same thing but without the absolute + + align:start position:0% +same thing but without the absolute + + + align:start position:0% +same thing but without the absolute +value okay so you see these guys stay + + align:start position:0% +value okay so you see these guys stay + + + align:start position:0% +value okay so you see these guys stay +total to zero so adding that term it + + align:start position:0% +total to zero so adding that term it + + + align:start position:0% +total to zero so adding that term it +doesn't change my expression but now the + + align:start position:0% +doesn't change my expression but now the + + + align:start position:0% +doesn't change my expression but now the +summon is always non-negative so it's + + align:start position:0% +summon is always non-negative so it's + + + align:start position:0% +summon is always non-negative so it's +either zero or twice this number + + align:start position:0% +either zero or twice this number + + + align:start position:0% +either zero or twice this number +depending on the sign of okay so + + align:start position:0% +depending on the sign of okay so + + + align:start position:0% +depending on the sign of okay so +comparing left hand side right hand side + + align:start position:0% +comparing left hand side right hand side + + + align:start position:0% +comparing left hand side right hand side +we see that there must be some I so + + align:start position:0% +we see that there must be some I so + + + align:start position:0% +we see that there must be some I so +hence this sum I such that the left hand + + align:start position:0% +hence this sum I such that the left hand + + + align:start position:0% +hence this sum I such that the left hand +side the ice term on the left hand side + + align:start position:0% +side the ice term on the left hand side + + + align:start position:0% +side the ice term on the left hand side +is less than or equal to the ice term on + + align:start position:0% +is less than or equal to the ice term on + + + align:start position:0% +is less than or equal to the ice term on +the right hand side and in particular + + align:start position:0% +the right hand side and in particular + + + align:start position:0% +the right hand side and in particular +that term should be positive so it + + align:start position:0% +that term should be positive so it + + + align:start position:0% +that term should be positive so it +implies okay so how can how can you get + + align:start position:0% +implies okay so how can how can you get + + + align:start position:0% +implies okay so how can how can you get +this inequality with it in pies simply + + align:start position:0% +this inequality with it in pies simply + + + align:start position:0% +this inequality with it in pies simply +that the restriction of a to this pie is + + align:start position:0% +that the restriction of a to this pie is + + + align:start position:0% +that the restriction of a to this pie is +at least alpha plus alpha squared over + + align:start position:0% +at least alpha plus alpha squared over + + + align:start position:0% +at least alpha plus alpha squared over +40 times so this claim here just says + + align:start position:0% +40 times so this claim here just says + + + align:start position:0% +40 times so this claim here just says +that on the ice progression there's a + + align:start position:0% +that on the ice progression there's a + + + align:start position:0% +that on the ice progression there's a +significant energy increment if it's + + align:start position:0% +significant energy increment if it's + + + align:start position:0% +significant energy increment if it's +worth decrement that term could have + + align:start position:0% +worth decrement that term could have + + + align:start position:0% +worth decrement that term could have +been zero + + align:start position:0% + + + + align:start position:0% + +okay so this achieves what we were + + align:start position:0% +okay so this achieves what we were + + + align:start position:0% +okay so this achieves what we were +looking for in step two namely to find + + align:start position:0% +looking for in step two namely to find + + + align:start position:0% +looking for in step two namely to find +that there's a density increment on some + + align:start position:0% +that there's a density increment on some + + + align:start position:0% +that there's a density increment on some +long sub progression now we can go to + + align:start position:0% +long sub progression now we can go to + + + align:start position:0% +long sub progression now we can go to +step three which is basically the same + + align:start position:0% +step three which is basically the same + + + align:start position:0% +step three which is basically the same +as we saw last time + + align:start position:0% +as we saw last time + + + align:start position:0% +as we saw last time +where now we want to iterate this + + align:start position:0% +where now we want to iterate this + + + align:start position:0% +where now we want to iterate this +density increment okay so it's basically + + align:start position:0% +density increment okay so it's basically + + + align:start position:0% +density increment okay so it's basically +the same argument as last time you start + + align:start position:0% +the same argument as last time you start + + + align:start position:0% +the same argument as last time you start +with density alpha and each step in the + + align:start position:0% +with density alpha and each step in the + + + align:start position:0% +with density alpha and each step in the +integration the density goes up quite a + + align:start position:0% +integration the density goes up quite a + + + align:start position:0% +integration the density goes up quite a +bit and we want to control the total + + align:start position:0% +bit and we want to control the total + + + align:start position:0% +bit and we want to control the total +number of steps knowing that the final + + align:start position:0% +number of steps knowing that the final + + + align:start position:0% +number of steps knowing that the final +density at most one always okay so how + + align:start position:0% +density at most one always okay so how + + + align:start position:0% +density at most one always okay so how +many steps can you take so this was the + + align:start position:0% +many steps can you take so this was the + + + align:start position:0% +many steps can you take so this was the +same argument that we saw last time you + + align:start position:0% +same argument that we saw last time you + + + align:start position:0% +same argument that we saw last time you +see that starting with alpha or not + + align:start position:0% +see that starting with alpha or not + + + align:start position:0% +see that starting with alpha or not +alpha if doubles after certain number of + + align:start position:0% +alpha if doubles after certain number of + + + align:start position:0% +alpha if doubles after certain number of +steps we double after okay so how many + + align:start position:0% +steps we double after okay so how many + + + align:start position:0% +steps we double after okay so how many +steps do you need well I want to get + + align:start position:0% +steps do you need well I want to get + + + align:start position:0% +steps do you need well I want to get +from alpha 2 to alpha so I need at most + + align:start position:0% +from alpha 2 to alpha so I need at most + + + align:start position:0% +from alpha 2 to alpha so I need at most +alpha over 40 steps ok so last time I + + align:start position:0% +alpha over 40 steps ok so last time I + + + align:start position:0% +alpha over 40 steps ok so last time I +was slightly sloppy and so there's a + + align:start position:0% +was slightly sloppy and so there's a + + + align:start position:0% +was slightly sloppy and so there's a +basically a floor up or floor down + + align:start position:0% +basically a floor up or floor down + + + align:start position:0% +basically a floor up or floor down +sitting up or down situation but I + + align:start position:0% +sitting up or down situation but I + + + align:start position:0% +sitting up or down situation but I +should add a plus one yeah + + align:start position:0% +should add a plus one yeah + + + align:start position:0% +should add a plus one yeah +40 40 over alpha so you double after at + + align:start position:0% +40 40 over alpha so you double after at + + + align:start position:0% +40 40 over alpha so you double after at +most that many steps and then now you + + align:start position:0% +most that many steps and then now you + + + align:start position:0% +most that many steps and then now you +are at density at least 2 alpha so we + + align:start position:0% +are at density at least 2 alpha so we + + + align:start position:0% +are at density at least 2 alpha so we +double after at most 20 over alpha steps + + align:start position:0% +double after at most 20 over alpha steps + + + align:start position:0% +double after at most 20 over alpha steps +and so on and we double at most + + align:start position:0% +and so on and we double at most + + + align:start position:0% +and so on and we double at most +basically log sub 2 of 1 over alpha + + align:start position:0% +basically log sub 2 of 1 over alpha + + + align:start position:0% +basically log sub 2 of 1 over alpha +times okay so anyway putting everything + + align:start position:0% +times okay so anyway putting everything + + + align:start position:0% +times okay so anyway putting everything +together we see that the total number of + + align:start position:0% +together we see that the total number of + + + align:start position:0% +together we see that the total number of +steps + + align:start position:0% + + + + align:start position:0% + +yes and most on the order of 1 over + + align:start position:0% +yes and most on the order of 1 over + + + align:start position:0% +yes and most on the order of 1 over +alpha when you stop you can only stop + + align:start position:0% +alpha when you stop you can only stop + + + align:start position:0% +alpha when you stop you can only stop +for one reason because in the so so in + + align:start position:0% +for one reason because in the so so in + + + align:start position:0% +for one reason because in the so so in +step 1 + + align:start position:0% +step 1 + + + align:start position:0% +step 1 +remember the iteration said that the + + align:start position:0% +remember the iteration said that the + + + align:start position:0% +remember the iteration said that the +process terminates process can always go + + align:start position:0% +process terminates process can always go + + + align:start position:0% +process terminates process can always go +on and it terminates if the length 2 now + + align:start position:0% +on and it terminates if the length 2 now + + + align:start position:0% +on and it terminates if the length 2 now +a step I so let ni be the length of the + + align:start position:0% +a step I so let ni be the length of the + + + align:start position:0% +a step I so let ni be the length of the +progression that step I is at most C + + align:start position:0% +progression that step I is at most C + + + align:start position:0% +progression that step I is at most C +times alpha I to the minus 12 provided + + align:start position:0% +times alpha I to the minus 12 provided + + + align:start position:0% +times alpha I to the minus 12 provided +that n is large enough you can always + + align:start position:0% +that n is large enough you can always + + + align:start position:0% +that n is large enough you can always +pass to a sub progression and here you + + align:start position:0% +pass to a sub progression and here you + + + align:start position:0% +pass to a sub progression and here you +know when you pass the sub progression + + align:start position:0% +know when you pass the sub progression + + + align:start position:0% +know when you pass the sub progression +of course you can read label that sub + + align:start position:0% +of course you can read label that sub + + + align:start position:0% +of course you can read label that sub +progression and it's now 1 through n I + + align:start position:0% +progression and it's now 1 through n I + + + align:start position:0% +progression and it's now 1 through n I +so I can it's all the progressions are + + align:start position:0% +so I can it's all the progressions are + + + align:start position:0% +so I can it's all the progressions are +basically the same as the first set of + + align:start position:0% +basically the same as the first set of + + + align:start position:0% +basically the same as the first set of +positive integers prefix of the positive + + align:start position:0% +positive integers prefix of the positive + + + align:start position:0% +positive integers prefix of the positive +integers so when we stop a step I you + + align:start position:0% +integers so when we stop a step I you + + + align:start position:0% +integers so when we stop a step I you +must have n sub I being + + align:start position:0% +must have n sub I being + + + align:start position:0% +must have n sub I being +most this quantity over here which is at + + align:start position:0% +most this quantity over here which is at + + + align:start position:0% +most this quantity over here which is at +most C times the initial density raised + + align:start position:0% +most C times the initial density raised + + + align:start position:0% +most C times the initial density raised +to this minus 12 so therefore the + + align:start position:0% +to this minus 12 so therefore the + + + align:start position:0% +to this minus 12 so therefore the +initial length n of the space is bounded + + align:start position:0% +initial length n of the space is bounded + + + align:start position:0% +initial length n of the space is bounded +by each time we went down by a cube root + + align:start position:0% +by each time we went down by a cube root + + + align:start position:0% +by each time we went down by a cube root +at most right so you find if you stop a + + align:start position:0% +at most right so you find if you stop a + + + align:start position:0% +at most right so you find if you stop a +step I then the initial length is at + + align:start position:0% +step I then the initial length is at + + + align:start position:0% +step I then the initial length is at +most n sub I to the 3 times 3 to the + + align:start position:0% +most n sub I to the 3 times 3 to the + + + align:start position:0% +most n sub I to the 3 times 3 to the +power of I each time you're doing a cube + + align:start position:0% +power of I each time you're doing a cube + + + align:start position:0% +power of I each time you're doing a cube +root okay so you put everything together + + align:start position:0% +root okay so you put everything together + + + align:start position:0% +root okay so you put everything together +that most time in the iterations when + + align:start position:0% +that most time in the iterations when + + + align:start position:0% +that most time in the iterations when +you stop the length is at most this so + + align:start position:0% +you stop the length is at most this so + + + align:start position:0% +you stop the length is at most this so +you put them together and then you find + + align:start position:0% +you put them together and then you find + + + align:start position:0% +you put them together and then you find +that the n must be at most double + + align:start position:0% +that the n must be at most double + + + align:start position:0% +that the n must be at most double +exponential in 1 over the density in + + align:start position:0% +exponential in 1 over the density in + + + align:start position:0% +exponential in 1 over the density in +other words density is at most 1 over + + align:start position:0% +other words density is at most 1 over + + + align:start position:0% +other words density is at most 1 over +log log n which is what we claimed in + + align:start position:0% +log log n which is what we claimed in + + + align:start position:0% +log log n which is what we claimed in +Ross theorem okay so that finishes the + + align:start position:0% +Ross theorem okay so that finishes the + + + align:start position:0% +Ross theorem okay so that finishes the +proof + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +any questions so the message here is + + align:start position:0% +any questions so the message here is + + + align:start position:0% +any questions so the message here is +that it's the same proof as last time + + align:start position:0% +that it's the same proof as last time + + + align:start position:0% +that it's the same proof as last time +but we need to do a bit more work and + + align:start position:0% +but we need to do a bit more work and + + + align:start position:0% +but we need to do a bit more work and +none of this work is difficult but + + align:start position:0% +none of this work is difficult but + + + align:start position:0% +none of this work is difficult but +they're more technical and that's often + + align:start position:0% +they're more technical and that's often + + + align:start position:0% +they're more technical and that's often +a theme that you see in additive + + align:start position:0% +a theme that you see in additive + + + align:start position:0% +a theme that you see in additive +combinatorics this is part of the reason + + align:start position:0% +combinatorics this is part of the reason + + + align:start position:0% +combinatorics this is part of the reason +why the finite field model is a really + + align:start position:0% +why the finite field model is a really + + + align:start position:0% +why the finite field model is a really +nice playground because there are things + + align:start position:0% +nice playground because there are things + + + align:start position:0% +nice playground because there are things +tend to be often cleaner but the ideas + + align:start position:0% +tend to be often cleaner but the ideas + + + align:start position:0% +tend to be often cleaner but the ideas +are often similar or the same ideas not + + align:start position:0% +are often similar or the same ideas not + + + align:start position:0% +are often similar or the same ideas not +always next lecture we'll see you one + + align:start position:0% +always next lecture we'll see you one + + + align:start position:0% +always next lecture we'll see you one +technique where there's a dramatic + + align:start position:0% +technique where there's a dramatic + + + align:start position:0% +technique where there's a dramatic +difference between the finite field + + align:start position:0% +difference between the finite field + + + align:start position:0% +difference between the finite field +vector space and over the integers but + + align:start position:0% +vector space and over the integers but + + + align:start position:0% +vector space and over the integers but +for many things in additive + + align:start position:0% +for many things in additive + + + align:start position:0% +for many things in additive +combinatorics define a fuel vector space + + align:start position:0% +combinatorics define a fuel vector space + + + align:start position:0% +combinatorics define a fuel vector space +is just a nicer place to be in to try + + align:start position:0% +is just a nicer place to be in to try + + + align:start position:0% +is just a nicer place to be in to try +all your ideas and techniques what let + + align:start position:0% +all your ideas and techniques what let + + + align:start position:0% +all your ideas and techniques what let +me comment on some analogies between + + align:start position:0% +me comment on some analogies between + + + align:start position:0% +me comment on some analogies between +these two approaches and compare the + + align:start position:0% +these two approaches and compare the + + + align:start position:0% +these two approaches and compare the +bounds so on one hand so we saw last + + align:start position:0% +bounds so on one hand so we saw last + + + align:start position:0% +bounds so on one hand so we saw last +time is proof in FP to the end now the + + align:start position:0% +time is proof in FP to the end now the + + + align:start position:0% +time is proof in FP to the end now the +integers inside this interval of length + + align:start position:0% +integers inside this interval of length + + + align:start position:0% +integers inside this interval of length +so let me write uppercase and in both + + align:start position:0% +so let me write uppercase and in both + + + align:start position:0% +so let me write uppercase and in both +cases to be the size of the overall + + align:start position:0% +cases to be the size of the overall + + + align:start position:0% +cases to be the size of the overall +ambient space so what kind of bounds do + + align:start position:0% +ambient space so what kind of bounds do + + + align:start position:0% +ambient space so what kind of bounds do +we get in both situations so last time + + align:start position:0% +we get in both situations so last time + + + align:start position:0% +we get in both situations so last time +for in F 3 to the end we got a bound + + align:start position:0% + + + + align:start position:0% + +which is of the order and over log n + + align:start position:0% +which is of the order and over log n + + + align:start position:0% +which is of the order and over log n +whereas today + + align:start position:0% + + + + align:start position:0% + +pound is somewhat worse a little bit + + align:start position:0% +pound is somewhat worse a little bit + + + align:start position:0% +pound is somewhat worse a little bit +worse now we lose an extra lock so where + + align:start position:0% +worse now we lose an extra lock so where + + + align:start position:0% +worse now we lose an extra lock so where +do we lose an extra lock in this + + align:start position:0% +do we lose an extra lock in this + + + align:start position:0% +do we lose an extra lock in this +argument so where does these two + + align:start position:0% +argument so where does these two + + + align:start position:0% +argument so where does these two +argument where do these two arguments + + align:start position:0% +argument where do these two arguments + + + align:start position:0% +argument where do these two arguments +differ qualitatively okay so you're + + align:start position:0% +differ qualitatively okay so you're + + + align:start position:0% +differ qualitatively okay so you're +dividing by so here in each iteration + + align:start position:0% + + + + align:start position:0% + +over here your size of the iteration I + + align:start position:0% +over here your size of the iteration I + + + align:start position:0% +over here your size of the iteration I +mean iteration the size of the space + + align:start position:0% +mean iteration the size of the space + + + align:start position:0% +mean iteration the size of the space +goes down by a factor three whereas over + + align:start position:0% +goes down by a factor three whereas over + + + align:start position:0% +goes down by a factor three whereas over +here it could go down by a cube root and + + align:start position:0% +here it could go down by a cube root and + + + align:start position:0% +here it could go down by a cube root and +that's that's precisely right so that + + align:start position:0% +that's that's precisely right so that + + + align:start position:0% +that's that's precisely right so that +explains for this extra lock in the + + align:start position:0% +explains for this extra lock in the + + + align:start position:0% +explains for this extra lock in the +bounds so while this is a great analogy + + align:start position:0% +bounds so while this is a great analogy + + + align:start position:0% +bounds so while this is a great analogy +it's not a perfect analogy you see there + + align:start position:0% +it's not a perfect analogy you see there + + + align:start position:0% +it's not a perfect analogy you see there +is a divergence here between the two + + align:start position:0% +is a divergence here between the two + + + align:start position:0% +is a divergence here between the two +situations and so then you might ask is + + align:start position:0% +situations and so then you might ask is + + + align:start position:0% +situations and so then you might ask is +there some way to avoid the loss this + + align:start position:0% +there some way to avoid the loss this + + + align:start position:0% +there some way to avoid the loss this +extra log factor loss over here is there + + align:start position:0% +extra log factor loss over here is there + + + align:start position:0% +extra log factor loss over here is there +some way to carry out the strategy that + + align:start position:0% +some way to carry out the strategy that + + + align:start position:0% +some way to carry out the strategy that +we did last time in a way that is much + + align:start position:0% +we did last time in a way that is much + + + align:start position:0% +we did last time in a way that is much +more faithful to that strategy of + + align:start position:0% +more faithful to that strategy of + + + align:start position:0% +more faithful to that strategy of +passing down to subspaces so here we + + align:start position:0% +passing down to subspaces so here we + + + align:start position:0% +passing down to subspaces so here we +pass two progressions and because we + + align:start position:0% +pass two progressions and because we + + + align:start position:0% +pass two progressions and because we +have do this extra you know pigeonhole + + align:start position:0% +have do this extra you know pigeonhole + + + align:start position:0% +have do this extra you know pigeonhole +type argument it was somewhat lost we + + align:start position:0% +type argument it was somewhat lost we + + + align:start position:0% +type argument it was somewhat lost we +lost a power which translated into this + + align:start position:0% +lost a power which translated into this + + + align:start position:0% +lost a power which translated into this +extra log so it turns out there there is + + align:start position:0% +extra log so it turns out there there is + + + align:start position:0% +extra log so it turns out there there is +some way to do this so let me just + + align:start position:0% +some way to do this so let me just + + + align:start position:0% +some way to do this so let me just +briefly mention what's the idea that is + + align:start position:0% +briefly mention what's the idea that is + + + align:start position:0% +briefly mention what's the idea that is +involved so last time we went down from + + align:start position:0% +involved so last time we went down from + + + align:start position:0% +involved so last time we went down from +so the main objects that we were passing + + align:start position:0% +so the main objects that we were passing + + + align:start position:0% +so the main objects that we were passing +or start with a vector space and passed + + align:start position:0% +or start with a vector space and passed + + + align:start position:0% +or start with a vector space and passed +down to a subspace which is also a + + align:start position:0% +down to a subspace which is also a + + + align:start position:0% +down to a subspace which is also a +vector space so you can define subspaces + + align:start position:0% +vector space so you can define subspaces + + + align:start position:0% +vector space so you can define subspaces +in a street the end by the following so + + align:start position:0% +in a street the end by the following so + + + align:start position:0% +in a street the end by the following so +I can start with some set of characters + + align:start position:0% +I can start with some set of characters + + + align:start position:0% +I can start with some set of characters +you and I define as some set of + + align:start position:0% +you and I define as some set of + + + align:start position:0% +you and I define as some set of +characters s and I define u sub s to be + + align:start position:0% +characters s and I define u sub s to be + + + align:start position:0% +characters s and I define u sub s to be +basically the orthogonal complement of s + + align:start position:0% + + + + align:start position:0% + +ok so this is a subspace and these were + + align:start position:0% +ok so this is a subspace and these were + + + align:start position:0% +ok so this is a subspace and these were +the kind of subspaces that we saw last + + align:start position:0% +the kind of subspaces that we saw last + + + align:start position:0% +the kind of subspaces that we saw last +time because the SS or the ARS that came + + align:start position:0% +time because the SS or the ARS that came + + + align:start position:0% +time because the SS or the ARS that came +out of the proof last time every time we + + align:start position:0% +out of the proof last time every time we + + + align:start position:0% +out of the proof last time every time we +saw bond we throw it in we cut down to a + + align:start position:0% +saw bond we throw it in we cut down to a + + + align:start position:0% +saw bond we throw it in we cut down to a +smaller subspace and we repeat but the + + align:start position:0% +smaller subspace and we repeat but the + + + align:start position:0% +smaller subspace and we repeat but the +progressions they don't really look like + + align:start position:0% +progressions they don't really look like + + + align:start position:0% +progressions they don't really look like +this alright so the question is is there + + align:start position:0% +this alright so the question is is there + + + align:start position:0% +this alright so the question is is there +some way to do this argument so that you + + align:start position:0% +some way to do this argument so that you + + + align:start position:0% +some way to do this argument so that you +end up with progressions and look like + + align:start position:0% +end up with progressions and look like + + + align:start position:0% +end up with progressions and look like +that and it turns out there is a way and + + align:start position:0% +that and it turns out there is a way and + + + align:start position:0% +that and it turns out there is a way and +there are these objects which will see + + align:start position:0% +there are these objects which will see + + + align:start position:0% +there are these objects which will see +more later in this course called poor + + align:start position:0% +more later in this course called poor + + + align:start position:0% +more later in this course called poor +sets okay so they were used by poor gain + + align:start position:0% +sets okay so they were used by poor gain + + + align:start position:0% +sets okay so they were used by poor gain +to mimic this machine an argument that + + align:start position:0% +to mimic this machine an argument that + + + align:start position:0% +to mimic this machine an argument that +we saw last time more faithfully into + + align:start position:0% +we saw last time more faithfully into + + + align:start position:0% +we saw last time more faithfully into +the integers where we're going to come + + align:start position:0% +the integers where we're going to come + + + align:start position:0% +the integers where we're going to come +up with some set of integers that + + align:start position:0% +up with some set of integers that + + + align:start position:0% +up with some set of integers that +resemble the much closed more closely + + align:start position:0% +resemble the much closed more closely + + + align:start position:0% +resemble the much closed more closely +resemble this notion of subspaces + + align:start position:0% +resemble this notion of subspaces + + + align:start position:0% +resemble this notion of subspaces +in the finite field setting and for this + + align:start position:0% +in the finite field setting and for this + + + align:start position:0% +in the finite field setting and for this +it's much easier to work inside a group + + align:start position:0% +it's much easier to work inside a group + + + align:start position:0% +it's much easier to work inside a group +so instead of working in the integers + + align:start position:0% +so instead of working in the integers + + + align:start position:0% +so instead of working in the integers +let's work inside Z mod and Z so we can + + align:start position:0% +let's work inside Z mod and Z so we can + + + align:start position:0% +let's work inside Z mod and Z so we can +do Fourier transform in Z mod NZ so the + + align:start position:0% +do Fourier transform in Z mod NZ so the + + + align:start position:0% +do Fourier transform in Z mod NZ so the +discrete Fourier analysis here so in Z + + align:start position:0% +discrete Fourier analysis here so in Z + + + align:start position:0% +discrete Fourier analysis here so in Z +mod NZ we define so given an S let's + + align:start position:0% +mod NZ we define so given an S let's + + + align:start position:0% +mod NZ we define so given an S let's +define the spore set to be the set of + + align:start position:0% +define the spore set to be the set of + + + align:start position:0% +define the spore set to be the set of +elements of NZ such that if you look at + + align:start position:0% +elements of NZ such that if you look at + + + align:start position:0% +elements of NZ such that if you look at +what really is supposed to resemble this + + align:start position:0% +what really is supposed to resemble this + + + align:start position:0% +what really is supposed to resemble this +this thing over here if this quantity is + + align:start position:0% +this thing over here if this quantity is + + + align:start position:0% +this thing over here if this quantity is +small for all s so we put that element + + align:start position:0% +small for all s so we put that element + + + align:start position:0% +small for all s so we put that element +into the spore set so these sets they + + align:start position:0% +into the spore set so these sets they + + + align:start position:0% +into the spore set so these sets they +they function much more like subspaces + + align:start position:0% +they function much more like subspaces + + + align:start position:0% +they function much more like subspaces +so there are the analogy of subspaces + + align:start position:0% +so there are the analogy of subspaces + + + align:start position:0% +so there are the analogy of subspaces +inside G mod n Z which n is prime has no + + align:start position:0% +inside G mod n Z which n is prime has no + + + align:start position:0% +inside G mod n Z which n is prime has no +subgroups it has no natural subspace + + align:start position:0% +subgroups it has no natural subspace + + + align:start position:0% +subgroups it has no natural subspace +structure but by looking at these four + + align:start position:0% +structure but by looking at these four + + + align:start position:0% +structure but by looking at these four +sets they provide a natural way to set + + align:start position:0% +sets they provide a natural way to set + + + align:start position:0% +sets they provide a natural way to set +up this argument so that you can but + + align:start position:0% +up this argument so that you can but + + + align:start position:0% +up this argument so that you can but +with much more technicalities repeat + + align:start position:0% +with much more technicalities repeat + + + align:start position:0% +with much more technicalities repeat +this kind of arguments more similar to + + align:start position:0% +this kind of arguments more similar to + + + align:start position:0% +this kind of arguments more similar to +last time but passing not subspaces but + + align:start position:0% +last time but passing not subspaces but + + + align:start position:0% +last time but passing not subspaces but +to poor sets and and then with quite a + + align:start position:0% +to poor sets and and then with quite a + + + align:start position:0% +to poor sets and and then with quite a +bit of extra work one can obtain bounds + + align:start position:0% +bit of extra work one can obtain bounds + + + align:start position:0% +bit of extra work one can obtain bounds +of the quantity and over poly block so + + align:start position:0% +of the quantity and over poly block so + + + align:start position:0% +of the quantity and over poly block so +the current best bound I mentioned last + + align:start position:0% +the current best bound I mentioned last + + + align:start position:0% +the current best bound I mentioned last +time this of this type was just through + + align:start position:0% +time this of this type was just through + + + align:start position:0% +time this of this type was just through +further refinements of this technique + + align:start position:0% + + + + align:start position:0% + +questions + + align:start position:0% + + + + align:start position:0% + +the last thing I want to mention today + + align:start position:0% +the last thing I want to mention today + + + align:start position:0% +the last thing I want to mention today +is so far we've been talking about three + + align:start position:0% +is so far we've been talking about three + + + align:start position:0% +is so far we've been talking about three +APs + + align:start position:0% +APs + + + align:start position:0% +APs +so what about four term arithmetic + + align:start position:0% +so what about four term arithmetic + + + align:start position:0% +so what about four term arithmetic +progressions doing any of the things + + align:start position:0% +progressions doing any of the things + + + align:start position:0% +progressions doing any of the things +that we talked about here + + align:start position:0% +that we talked about here + + + align:start position:0% +that we talked about here +work for for a piece and there's an + + align:start position:0% +work for for a piece and there's an + + + align:start position:0% +work for for a piece and there's an +analogy to be made here compared to what + + align:start position:0% +analogy to be made here compared to what + + + align:start position:0% +analogy to be made here compared to what +we discussed with graphs or so you grasp + + align:start position:0% +we discussed with graphs or so you grasp + + + align:start position:0% +we discussed with graphs or so you grasp +from kind of triangle counting them on a + + align:start position:0% +from kind of triangle counting them on a + + + align:start position:0% +from kind of triangle counting them on a +triangle remove all mm and then we said + + align:start position:0% +triangle remove all mm and then we said + + + align:start position:0% +triangle remove all mm and then we said +that the proof for a piece we will need + + align:start position:0% +that the proof for a piece we will need + + + align:start position:0% +that the proof for a piece we will need +the hypergraph version the simplex + + align:start position:0% +the hypergraph version the simplex + + + align:start position:0% +the hypergraph version the simplex +removal lemma hypergraph regularity + + align:start position:0% +removal lemma hypergraph regularity + + + align:start position:0% +removal lemma hypergraph regularity +lemma and now it's much more difficult + + align:start position:0% +lemma and now it's much more difficult + + + align:start position:0% +lemma and now it's much more difficult +and that analogy carries two and the + + align:start position:0% +and that analogy carries two and the + + + align:start position:0% +and that analogy carries two and the +same kind of difficulties that come up + + align:start position:0% +same kind of difficulties that come up + + + align:start position:0% +same kind of difficulties that come up +so it can be done but you need something + + align:start position:0% +so it can be done but you need something + + + align:start position:0% +so it can be done but you need something +more and the main message I want you to + + align:start position:0% +more and the main message I want you to + + + align:start position:0% +more and the main message I want you to +take away is that for a piece well we + + align:start position:0% +take away is that for a piece well we + + + align:start position:0% +take away is that for a piece well we +had a counting memo that says that + + align:start position:0% +had a counting memo that says that + + + align:start position:0% +had a counting memo that says that +Fourier coefficients and Fourier + + align:start position:0% +Fourier coefficients and Fourier + + + align:start position:0% +Fourier coefficients and Fourier +transform controls 3 MP caps it turns + + align:start position:0% +transform controls 3 MP caps it turns + + + align:start position:0% +transform controls 3 MP caps it turns +out the same is not true for foil please + + align:start position:0% +out the same is not true for foil please + + + align:start position:0% +out the same is not true for foil please +so for you that's not let me give you + + align:start position:0% +so for you that's not let me give you + + + align:start position:0% +so for you that's not let me give you +some okay so in fact in the homework for + + align:start position:0% +some okay so in fact in the homework for + + + align:start position:0% +some okay so in fact in the homework for +this week there is a specific example of + + align:start position:0% +this week there is a specific example of + + + align:start position:0% +this week there is a specific example of +a set where it has uniformly small + + align:start position:0% +a set where it has uniformly small + + + align:start position:0% +a set where it has uniformly small +Fourier coefficients but that's a wrong + + align:start position:0% +Fourier coefficients but that's a wrong + + + align:start position:0% +Fourier coefficients but that's a wrong +number of 40-piece so the following it + + align:start position:0% +number of 40-piece so the following it + + + align:start position:0% +number of 40-piece so the following it +is true ok so it is true that you have + + align:start position:0% +is true ok so it is true that you have + + + align:start position:0% +is true ok so it is true that you have +some readies theorem in let's just talk + + align:start position:0% +some readies theorem in let's just talk + + + align:start position:0% +some readies theorem in let's just talk +about the finite field setting where + + align:start position:0% +about the finite field setting where + + + align:start position:0% +about the finite field setting where +things are bit easier to discuss so it + + align:start position:0% +things are bit easier to discuss so it + + + align:start position:0% +things are bit easier to discuss so it +is true that the size of the biggest + + align:start position:0% +is true that the size of the biggest + + + align:start position:0% +is true that the size of the biggest +subset of F 5 to the N is a tiny + + align:start position:0% +subset of F 5 to the N is a tiny + + + align:start position:0% +subset of F 5 to the N is a tiny +fraction it's a little one fraction with + + align:start position:0% +fraction it's a little one fraction with + + + align:start position:0% +fraction it's a little one fraction with +the entire space I use f5 here because + + align:start position:0% +the entire space I use f5 here because + + + align:start position:0% +the entire space I use f5 here because +if I set F 3 it doesn't make sense to + + align:start position:0% +if I set F 3 it doesn't make sense to + + + align:start position:0% +if I set F 3 it doesn't make sense to +talk about four ATP's so at five but it + + align:start position:0% +talk about four ATP's so at five but it + + + align:start position:0% +talk about four ATP's so at five but it +doesn't really matter which specific + + align:start position:0% +doesn't really matter which specific + + + align:start position:0% +doesn't really matter which specific +field so you can prove this using + + align:start position:0% +field so you can prove this using + + + align:start position:0% +field so you can prove this using +hypergraph removal say + + align:start position:0% +hypergraph removal say + + + align:start position:0% +hypergraph removal say +proof verbatim that we saw earlier if + + align:start position:0% +proof verbatim that we saw earlier if + + + align:start position:0% +proof verbatim that we saw earlier if +you have hypergraph removal but if you + + align:start position:0% +you have hypergraph removal but if you + + + align:start position:0% +you have hypergraph removal but if you +want to try to prove it using Fourier + + align:start position:0% +want to try to prove it using Fourier + + + align:start position:0% +want to try to prove it using Fourier +analysis or it doesn't work quite using + + align:start position:0% +analysis or it doesn't work quite using + + + align:start position:0% +analysis or it doesn't work quite using +the same strategy but in fact there is a + + align:start position:0% +the same strategy but in fact there is a + + + align:start position:0% +the same strategy but in fact there is a +modification that would allow you to to + + align:start position:0% +modification that would allow you to to + + + align:start position:0% +modification that would allow you to to +make it work but you need an extension + + align:start position:0% +make it work but you need an extension + + + align:start position:0% +make it work but you need an extension +of Fourier analysis and it was known as + + align:start position:0% +of Fourier analysis and it was known as + + + align:start position:0% +of Fourier analysis and it was known as +higher order for your analysis which was + + align:start position:0% +higher order for your analysis which was + + + align:start position:0% +higher order for your analysis which was +an important development in modern + + align:start position:0% +an important development in modern + + + align:start position:0% +an important development in modern +additive combinatorics that initially + + align:start position:0% +additive combinatorics that initially + + + align:start position:0% +additive combinatorics that initially +arose in Gao versus work where he gave a + + align:start position:0% +arose in Gao versus work where he gave a + + + align:start position:0% +arose in Gao versus work where he gave a +new proof of samurais theorem so towers + + align:start position:0% +new proof of samurais theorem so towers + + + align:start position:0% +new proof of samurais theorem so towers +didn't work in this setting he worked in + + align:start position:0% +didn't work in this setting he worked in + + + align:start position:0% +didn't work in this setting he worked in +integers but many of the ideas + + align:start position:0% +integers but many of the ideas + + + align:start position:0% +integers but many of the ideas +originated from from his paper and then + + align:start position:0% +originated from from his paper and then + + + align:start position:0% +originated from from his paper and then +subsequently developed lots of people in + + align:start position:0% +subsequently developed lots of people in + + + align:start position:0% +subsequently developed lots of people in +various settings I just want to give you + + align:start position:0% +various settings I just want to give you + + + align:start position:0% +various settings I just want to give you +one specific statement what this higher + + align:start position:0% +one specific statement what this higher + + + align:start position:0% +one specific statement what this higher +order Fourier analysis looks like it's a + + align:start position:0% +order Fourier analysis looks like it's a + + + align:start position:0% +order Fourier analysis looks like it's a +fancy term and you know statements often + + align:start position:0% +fancy term and you know statements often + + + align:start position:0% +fancy term and you know statements often +get very technical but I just want to + + align:start position:0% +get very technical but I just want to + + + align:start position:0% +get very technical but I just want to +give you one concrete thing to take away + + align:start position:0% +give you one concrete thing to take away + + + align:start position:0% +give you one concrete thing to take away +all right so for for a piece higher + + align:start position:0% +all right so for for a piece higher + + + align:start position:0% +all right so for for a piece higher +order for analysis roughly it also goes + + align:start position:0% +order for analysis roughly it also goes + + + align:start position:0% +order for analysis roughly it also goes +by the name of quadratic for urinalysis + + align:start position:0% + + + + align:start position:0% + +so let me give you a very specific + + align:start position:0% + + + + align:start position:0% + +instance of the theorem and this can be + + align:start position:0% +instance of the theorem and this can be + + + align:start position:0% +instance of the theorem and this can be +sometimes called an inverse theorem for + + align:start position:0% +sometimes called an inverse theorem for + + + align:start position:0% +sometimes called an inverse theorem for +quadratic for you analysis + + align:start position:0% + + + + align:start position:0% + +suppose okay so for every Delta there + + align:start position:0% +suppose okay so for every Delta there + + + align:start position:0% +suppose okay so for every Delta there +exists some C such that following is + + align:start position:0% +exists some C such that following is + + + align:start position:0% +exists some C such that following is +true if a is a subset F Phi to the N + + align:start position:0% +true if a is a subset F Phi to the N + + + align:start position:0% +true if a is a subset F Phi to the N +with density alpha and such that it's so + + align:start position:0% +with density alpha and such that it's so + + + align:start position:0% +with density alpha and such that it's so +now lambda sub four so this is the for + + align:start position:0% +now lambda sub four so this is the for + + + align:start position:0% +now lambda sub four so this is the for +AP density so similar to three a people + + align:start position:0% +AP density so similar to three a people + + + align:start position:0% +AP density so similar to three a people +now you write four terms the for AP + + align:start position:0% +now you write four terms the for AP + + + align:start position:0% +now you write four terms the for AP +density of a differs from + + align:start position:0% +density of a differs from + + + align:start position:0% +density of a differs from +alpha to the fourth by a significant + + align:start position:0% +alpha to the fourth by a significant + + + align:start position:0% +alpha to the fourth by a significant +amount okay so for three a piece then we + + align:start position:0% +amount okay so for three a piece then we + + + align:start position:0% +amount okay so for three a piece then we +said that now a has a large Fourier + + align:start position:0% +said that now a has a large Fourier + + + align:start position:0% +said that now a has a large Fourier +coefficient so for okay + + align:start position:0% +coefficient so for okay + + + align:start position:0% +coefficient so for okay +four for a piece that may not be true + + align:start position:0% +four for a piece that may not be true + + + align:start position:0% +four for a piece that may not be true +but the following is true so then there + + align:start position:0% +but the following is true so then there + + + align:start position:0% +but the following is true so then there +exists a nonzero quadratic polynomial F + + align:start position:0% +exists a nonzero quadratic polynomial F + + + align:start position:0% +exists a nonzero quadratic polynomial F +in n variables over a five such that the + + align:start position:0% +in n variables over a five such that the + + + align:start position:0% +in n variables over a five such that the +indicator function of a correlates with + + align:start position:0% +indicator function of a correlates with + + + align:start position:0% +indicator function of a correlates with +this quadratic exponential face so free + + align:start position:0% +this quadratic exponential face so free + + + align:start position:0% +this quadratic exponential face so free +analysis the conclusion that we got from + + align:start position:0% +analysis the conclusion that we got from + + + align:start position:0% +analysis the conclusion that we got from +counting lemma is that you have some + + align:start position:0% +counting lemma is that you have some + + + align:start position:0% +counting lemma is that you have some +linear function f such that this + + align:start position:0% +linear function f such that this + + + align:start position:0% +linear function f such that this +quantity is large this large Fourier + + align:start position:0% +quantity is large this large Fourier + + + align:start position:0% +quantity is large this large Fourier +coefficient okay so that is not true for + + align:start position:0% +coefficient okay so that is not true for + + + align:start position:0% +coefficient okay so that is not true for +for a piece but what is true is that now + + align:start position:0% +for a piece but what is true is that now + + + align:start position:0% +for a piece but what is true is that now +you can look at quadratic exponential + + align:start position:0% +you can look at quadratic exponential + + + align:start position:0% +you can look at quadratic exponential +faces and then this true so that's the + + align:start position:0% +faces and then this true so that's the + + + align:start position:0% +faces and then this true so that's the +content of higher order for you I mean + + align:start position:0% +content of higher order for you I mean + + + align:start position:0% +content of higher order for you I mean +that's the example of higher order + + align:start position:0% +that's the example of higher order + + + align:start position:0% +that's the example of higher order +Fourier analysis and you can imagine + + align:start position:0% +Fourier analysis and you can imagine + + + align:start position:0% +Fourier analysis and you can imagine +with this type of result and with quite + + align:start position:0% +with this type of result and with quite + + + align:start position:0% +with this type of result and with quite +a bit of more work you can try to follow + + align:start position:0% +a bit of more work you can try to follow + + + align:start position:0% +a bit of more work you can try to follow +a similar density increment strategy to + + align:start position:0% +a similar density increment strategy to + + + align:start position:0% +a similar density increment strategy to +prove similarities theorem for for a + + align:start position:0% +prove similarities theorem for for a + + + align:start position:0% +prove similarities theorem for for a +piece \ No newline at end of file diff --git a/56iFMY8QW2k.txt b/56iFMY8QW2k.txt new file mode 100644 index 0000000000000000000000000000000000000000..5ad404a4f064305ae336fa92bbc69fa21f66caf4 --- /dev/null +++ b/56iFMY8QW2k.txt @@ -0,0 +1,12371 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT open courseware continue + + align:start position:0% +will help MIT open courseware continue + + + align:start position:0% +will help MIT open courseware continue +to offer high quality educational + + align:start position:0% +to offer high quality educational + + + align:start position:0% +to offer high quality educational +resources for free to make a donation or + + align:start position:0% +resources for free to make a donation or + + + align:start position:0% +resources for free to make a donation or +view additional materials from hundreds + + align:start position:0% +view additional materials from hundreds + + + align:start position:0% +view additional materials from hundreds +of MIT courses visit MIT open courseware + + align:start position:0% +of MIT courses visit MIT open courseware + + + align:start position:0% +of MIT courses visit MIT open courseware +at + + align:start position:0% + + + + align:start position:0% + +ocw.mit.edu uh now today we're going to + + align:start position:0% +ocw.mit.edu uh now today we're going to + + + align:start position:0% +ocw.mit.edu uh now today we're going to +talk about random walks and in + + align:start position:0% +talk about random walks and in + + + align:start position:0% +talk about random walks and in +particular we're going to look at a + + align:start position:0% +particular we're going to look at a + + + align:start position:0% +particular we're going to look at a +classic phenomenon known as gamblers + + align:start position:0% +classic phenomenon known as gamblers + + + align:start position:0% +classic phenomenon known as gamblers +ruin uh it's a great way to end the term + + align:start position:0% +ruin uh it's a great way to end the term + + + align:start position:0% +ruin uh it's a great way to end the term +because the solution requires several of + + align:start position:0% +because the solution requires several of + + + align:start position:0% +because the solution requires several of +the techniques that we've developed + + align:start position:0% +the techniques that we've developed + + + align:start position:0% +the techniques that we've developed +since the midterm so it's actually a + + align:start position:0% +since the midterm so it's actually a + + + align:start position:0% +since the midterm so it's actually a +good review we'll review recurrences + + align:start position:0% +good review we'll review recurrences + + + align:start position:0% +good review we'll review recurrences +we'll review a lot of probability laws + + align:start position:0% +we'll review a lot of probability laws + + + align:start position:0% +we'll review a lot of probability laws +and it's uh it's actually a nice problem + + align:start position:0% +and it's uh it's actually a nice problem + + + align:start position:0% +and it's uh it's actually a nice problem +to look at it's it's another example + + align:start position:0% +to look at it's it's another example + + + align:start position:0% +to look at it's it's another example +where you get a non-intuitive solution + + align:start position:0% +where you get a non-intuitive solution + + + align:start position:0% +where you get a non-intuitive solution +using probability and if you like to + + align:start position:0% +using probability and if you like to + + + align:start position:0% +using probability and if you like to +gamble it's really good that you look at + + align:start position:0% +gamble it's really good that you look at + + + align:start position:0% +gamble it's really good that you look at +this problem before you go to Vegas or + + align:start position:0% +this problem before you go to Vegas or + + + align:start position:0% +this problem before you go to Vegas or +down to Foxwood + + align:start position:0% +down to Foxwood + + + align:start position:0% +down to Foxwood +now in the gambler's ruin + + align:start position:0% + + + + align:start position:0% + +problem you start with + + align:start position:0% + + + + align:start position:0% + +$1 and we're going to do a simplified + + align:start position:0% +$1 and we're going to do a simplified + + + align:start position:0% +$1 and we're going to do a simplified +version where in each bet you win a + + align:start position:0% +version where in each bet you win a + + + align:start position:0% +version where in each bet you win a +dollar or you lose a dollar now these + + align:start position:0% +dollar or you lose a dollar now these + + + align:start position:0% +dollar or you lose a dollar now these +days there's not many bets in a casino + + align:start position:0% +days there's not many bets in a casino + + + align:start position:0% +days there's not many bets in a casino +for a dollar it's more like like 10 + + align:start position:0% +for a dollar it's more like like 10 + + + align:start position:0% +for a dollar it's more like like 10 +bucks but just to make it simple for + + align:start position:0% +bucks but just to make it simple for + + + align:start position:0% +bucks but just to make it simple for +counting we're going to assume that each + + align:start position:0% +counting we're going to assume that each + + + align:start position:0% +counting we're going to assume that each +bet you win a dollar with probability + + align:start position:0% +bet you win a dollar with probability + + + align:start position:0% +bet you win a dollar with probability +p and you + + align:start position:0% +p and you + + + align:start position:0% +p and you +lose a + + align:start position:0% +lose a + + + align:start position:0% +lose a +dollar with + + align:start position:0% +dollar with + + + align:start position:0% +dollar with +probability one minus + + align:start position:0% +probability one minus + + + align:start position:0% +probability one minus +p and in this version we're going to + + align:start position:0% +p and in this version we're going to + + + align:start position:0% +p and in this version we're going to +assume you keep + + align:start position:0% +assume you keep + + + align:start position:0% +assume you keep +playing until one of two things happens + + align:start position:0% +playing until one of two things happens + + + align:start position:0% +playing until one of two things happens +you get ahead by MLL or you lose all the + + align:start position:0% +you get ahead by MLL or you lose all the + + + align:start position:0% +you get ahead by MLL or you lose all the +money you came with all + + align:start position:0% + + + + align:start position:0% + +nll so you play + + align:start position:0% + + + + align:start position:0% + +until you + + align:start position:0% +until you + + + align:start position:0% +until you +win M more net M plus or you + + align:start position:0% +win M more net M plus or you + + + align:start position:0% +win M more net M plus or you +lose + + align:start position:0% +lose + + + align:start position:0% +lose +n and that's where you go broke you run + + align:start position:0% +n and that's where you go broke you run + + + align:start position:0% +n and that's where you go broke you run +out of + + align:start position:0% + + + + align:start position:0% + +money and we're going to assume you + + align:start position:0% +money and we're going to assume you + + + align:start position:0% +money and we're going to assume you +don't Bor borrow anything from the + + align:start position:0% +don't Bor borrow anything from the + + + align:start position:0% +don't Bor borrow anything from the +house all right and we're going to look + + align:start position:0% +house all right and we're going to look + + + align:start position:0% +house all right and we're going to look +at the + + align:start position:0% +at the + + + align:start position:0% +at the +probability that you come out a winner + + align:start position:0% +probability that you come out a winner + + + align:start position:0% +probability that you come out a winner +versus going home broke that you you + + align:start position:0% +versus going home broke that you you + + + align:start position:0% +versus going home broke that you you +made + + align:start position:0% +made + + + align:start position:0% +made +MLL now the game we're going to + + align:start position:0% +MLL now the game we're going to + + + align:start position:0% +MLL now the game we're going to +analyze is roulette but the technique + + align:start position:0% +analyze is roulette but the technique + + + align:start position:0% +analyze is roulette but the technique +works for any of + + align:start position:0% + + + + align:start position:0% + +them how many people have played + + align:start position:0% +them how many people have played + + + align:start position:0% +them how many people have played +roulette before some form or another + + align:start position:0% +roulette before some form or another + + + align:start position:0% +roulette before some form or another +okay so this is the game where there's + + align:start position:0% +okay so this is the game where there's + + + align:start position:0% +okay so this is the game where there's +the ball that goes around on the dish + + align:start position:0% +the ball that goes around on the dish + + + align:start position:0% +the ball that goes around on the dish +and you spin the wheel and there's 36 + + align:start position:0% +and you spin the wheel and there's 36 + + + align:start position:0% +and you spin the wheel and there's 36 +numbers uh from 1 to 36 half of them are + + align:start position:0% +numbers uh from 1 to 36 half of them are + + + align:start position:0% +numbers uh from 1 to 36 half of them are +red half are black and then there's the + + align:start position:0% +red half are black and then there's the + + + align:start position:0% +red half are black and then there's the +zero and the double zero that are + + align:start position:0% +zero and the double zero that are + + + align:start position:0% +zero and the double zero that are +green and we're going to look at the + + align:start position:0% +green and we're going to look at the + + + align:start position:0% +green and we're going to look at the +version where you just bet on red are + + align:start position:0% +version where you just bet on red are + + + align:start position:0% +version where you just bet on red are +black and you win if the ball lands in a + + align:start position:0% +black and you win if the ball lands in a + + + align:start position:0% +black and you win if the ball lands in a +slot that's red and there's 18 of those + + align:start position:0% +slot that's red and there's 18 of those + + + align:start position:0% +slot that's red and there's 18 of those +and you lose + + align:start position:0% +and you lose + + + align:start position:0% +and you lose +otherwise so in this case the + + align:start position:0% +otherwise so in this case the + + + align:start position:0% +otherwise so in this case the +probability of winning + + align:start position:0% +probability of winning + + + align:start position:0% +probability of winning +p is there's 18 ch CH es to win and it's + + align:start position:0% +p is there's 18 ch CH es to win and it's + + + align:start position:0% +p is there's 18 ch CH es to win and it's +not 36 total it's 38 total because of + + align:start position:0% +not 36 total it's 38 total because of + + + align:start position:0% +not 36 total it's 38 total because of +the zero and the double zero all right + + align:start position:0% +the zero and the double zero all right + + + align:start position:0% +the zero and the double zero all right +so this is a 919 chance of winning and a + + align:start position:0% +so this is a 919 chance of winning and a + + + align:start position:0% +so this is a 919 chance of winning and a +1019 chance of + + align:start position:0% +1019 chance of + + + align:start position:0% +1019 chance of +losing and so this is a game that has a + + align:start position:0% +losing and so this is a game that has a + + + align:start position:0% +losing and so this is a game that has a +chance of winning of about + + align:start position:0% +chance of winning of about + + + align:start position:0% +chance of winning of about +47% so it's almost a fair game it's not + + align:start position:0% +47% so it's almost a fair game it's not + + + align:start position:0% +47% so it's almost a fair game it's not +50/50 and that's because the casino's + + align:start position:0% +50/50 and that's because the casino's + + + align:start position:0% +50/50 and that's because the casino's +got to make some money I mean they they + + align:start position:0% +got to make some money I mean they they + + + align:start position:0% +got to make some money I mean they they +have the big facility they're giving + + align:start position:0% +have the big facility they're giving + + + align:start position:0% +have the big facility they're giving +free drinks and all the rest so they got + + align:start position:0% +free drinks and all the rest so they got + + + align:start position:0% +free drinks and all the rest so they got +to make money somehow and they make + + align:start position:0% +to make money somehow and they make + + + align:start position:0% +to make money somehow and they make +money on this bet because you know + + align:start position:0% +money on this bet because you know + + + align:start position:0% +money on this bet because you know +they're going to make uh three cents you + + align:start position:0% +they're going to make uh three cents you + + + align:start position:0% +they're going to make uh three cents you +know on the dollar here you're going to + + align:start position:0% +know on the dollar here you're going to + + + align:start position:0% +know on the dollar here you're going to +wager and then you're going to come back + + align:start position:0% +wager and then you're going to come back + + + align:start position:0% +wager and then you're going to come back +with with + + align:start position:0% +with with + + + align:start position:0% +with with +47% and people generally are fine with + + align:start position:0% +47% and people generally are fine with + + + align:start position:0% +47% and people generally are fine with +that they don't expect to have the odds + + align:start position:0% +that they don't expect to have the odds + + + align:start position:0% +that they don't expect to have the odds +in their favor when you're gambling in a + + align:start position:0% +in their favor when you're gambling in a + + + align:start position:0% +in their favor when you're gambling in a +casino now in an effort to sort of come + + align:start position:0% +casino now in an effort to sort of come + + + align:start position:0% +casino now in an effort to sort of come +home a winner the way people do that + + align:start position:0% +home a winner the way people do that + + + align:start position:0% +home a winner the way people do that +knowing that the odds are a little + + align:start position:0% +knowing that the odds are a little + + + align:start position:0% +knowing that the odds are a little +against them is they might put more + + align:start position:0% +against them is they might put more + + + align:start position:0% +against them is they might put more +money in their pocket coming in than + + align:start position:0% +money in their pocket coming in than + + + align:start position:0% +money in their pocket coming in than +they expect to win so often you'll see + + align:start position:0% +they expect to win so often you'll see + + + align:start position:0% +they expect to win so often you'll see +people come in to the casino with a goal + + align:start position:0% +people come in to the casino with a goal + + + align:start position:0% +people come in to the casino with a goal +of winning a + + align:start position:0% +of winning a + + + align:start position:0% +of winning a +hundred but they start with a thousand + + align:start position:0% +hundred but they start with a thousand + + + align:start position:0% +hundred but they start with a thousand +in their + + align:start position:0% + + + + align:start position:0% + +pocket so they're willing to risk a + + align:start position:0% +pocket so they're willing to risk a + + + align:start position:0% +pocket so they're willing to risk a +th000 bucks and but they're going to + + align:start position:0% +th000 bucks and but they're going to + + + align:start position:0% +th000 bucks and but they're going to +quit happy if they get up a + + align:start position:0% +quit happy if they get up a + + + align:start position:0% +quit happy if they get up a +hundred + + align:start position:0% +hundred + + + align:start position:0% +hundred +okay so you're going to go home with + + align:start position:0% +okay so you're going to go home with + + + align:start position:0% +okay so you're going to go home with +$1,100 or you're going home with zero in + + align:start position:0% +$1,100 or you're going home with zero in + + + align:start position:0% +$1,100 or you're going home with zero in +this case and you came with a + + align:start position:0% +this case and you came with a + + + align:start position:0% +this case and you came with a +th000 and this means that you're at + + align:start position:0% +th000 and this means that you're at + + + align:start position:0% +th000 and this means that you're at +least the thinking goes this means that + + align:start position:0% +least the thinking goes this means that + + + align:start position:0% +least the thinking goes this means that +you're more likely to go home happy if + + align:start position:0% +you're more likely to go home happy if + + + align:start position:0% +you're more likely to go home happy if +you quit when you get up by a hundred + + align:start position:0% +you quit when you get up by a hundred + + + align:start position:0% +you quit when you get up by a hundred +you're more likely to land there because + + align:start position:0% +you're more likely to land there because + + + align:start position:0% +you're more likely to land there because +it's almost a fair game than you are to + + align:start position:0% +it's almost a fair game than you are to + + + align:start position:0% +it's almost a fair game than you are to +lose all + + align:start position:0% +lose all + + + align:start position:0% +lose all +thousand that's the thinking anyway in + + align:start position:0% +thousand that's the thinking anyway in + + + align:start position:0% +thousand that's the thinking anyway in +fact my mother-in-law plays roulette red + + align:start position:0% +fact my mother-in-law plays roulette red + + + align:start position:0% +fact my mother-in-law plays roulette red +and black and she follows the + + align:start position:0% +and black and she follows the + + + align:start position:0% +and black and she follows the +strategy you know and she claims that + + align:start position:0% +strategy you know and she claims that + + + align:start position:0% +strategy you know and she claims that +she does this for for that reason that + + align:start position:0% +she does this for for that reason that + + + align:start position:0% +she does this for for that reason that +she almost always wins you know she goes + + align:start position:0% +she almost always wins you know she goes + + + align:start position:0% +she almost always wins you know she goes +home happy almost always and that's the + + align:start position:0% +home happy almost always and that's the + + + align:start position:0% +home happy almost always and that's the +important thing here uh and it does + + align:start position:0% +important thing here uh and it does + + + align:start position:0% +important thing here uh and it does +sound reasonable because after all we're + + align:start position:0% +sound reasonable because after all we're + + + align:start position:0% +sound reasonable because after all we're +LED is almost a fair + + align:start position:0% +LED is almost a fair + + + align:start position:0% +LED is almost a fair +game so what do you think how many + + align:start position:0% +game so what do you think how many + + + align:start position:0% +game so what do you think how many +people think she's right that she almost + + align:start position:0% +people think she's right that she almost + + + align:start position:0% +people think she's right that she almost +always + + align:start position:0% +always + + + align:start position:0% +always +wins anybody I have sort of set it up + + align:start position:0% +wins anybody I have sort of set it up + + + align:start position:0% +wins anybody I have sort of set it up +it's my mother-in-law after all so + + align:start position:0% +it's my mother-in-law after all so + + + align:start position:0% +it's my mother-in-law after all so +probably she's going to be wrong you + + align:start position:0% +probably she's going to be wrong you + + + align:start position:0% +probably she's going to be wrong you +know + + align:start position:0% +know + + + align:start position:0% +know +uh well how many people think it's + + align:start position:0% +uh well how many people think it's + + + align:start position:0% +uh well how many people think it's +better than a 50% chance you win a 100 + + align:start position:0% +better than a 50% chance you win a 100 + + + align:start position:0% +better than a 50% chance you win a 100 +before you lose a + + align:start position:0% +before you lose a + + + align:start position:0% +before you lose a +thousand that's that's probably more 50 + + align:start position:0% +thousand that's that's probably more 50 + + + align:start position:0% +thousand that's that's probably more 50 +there's a how many people think you're + + align:start position:0% +there's a how many people think you're + + + align:start position:0% +there's a how many people think you're +more likely to lose a thousand bucks + + align:start position:0% +more likely to lose a thousand bucks + + + align:start position:0% +more likely to lose a thousand bucks +before you win a + + align:start position:0% +before you win a + + + align:start position:0% +before you win a +hundred wow okay so you've been to 604 + + align:start position:0% +hundred wow okay so you've been to 604 + + + align:start position:0% +hundred wow okay so you've been to 604 +too long now okay what about this how + + align:start position:0% +too long now okay what about this how + + + align:start position:0% +too long now okay what about this how +many people think you're more likely to + + align:start position:0% +many people think you're more likely to + + + align:start position:0% +many people think you're more likely to +lose + + align:start position:0% +lose + + + align:start position:0% +lose +$10,000 than to win a hundred + + align:start position:0% +$10,000 than to win a hundred + + + align:start position:0% +$10,000 than to win a hundred +all right how many people think you're + + align:start position:0% +all right how many people think you're + + + align:start position:0% +all right how many people think you're +more likely to lose a million + + align:start position:0% +more likely to lose a million + + + align:start position:0% +more likely to lose a million +dollars well a bunch of you still think + + align:start position:0% +dollars well a bunch of you still think + + + align:start position:0% +dollars well a bunch of you still think +that okay well you're right in fact it + + align:start position:0% +that okay well you're right in fact it + + + align:start position:0% +that okay well you're right in fact it +is almost certain you will go broke no + + align:start position:0% +is almost certain you will go broke no + + + align:start position:0% +is almost certain you will go broke no +matter how much money you bring before + + align:start position:0% +matter how much money you bring before + + + align:start position:0% +matter how much money you bring before +you win + + align:start position:0% +you win + + + align:start position:0% +you win +$100 okay in fact we're going to prove + + align:start position:0% +$100 okay in fact we're going to prove + + + align:start position:0% +$100 okay in fact we're going to prove +today that the probability that you win + + align:start position:0% +today that the probability that you win + + + align:start position:0% +today that the probability that you win +$100 + + align:start position:0% +$100 + + + align:start position:0% +$100 +before losing a hundred million if you + + align:start position:0% +before losing a hundred million if you + + + align:start position:0% +before losing a hundred million if you +stayed long enough that takes a + + align:start position:0% +stayed long enough that takes a + + + align:start position:0% +stayed long enough that takes a +while the chance you go home a winner is + + align:start position:0% +while the chance you go home a winner is + + + align:start position:0% +while the chance you go home a winner is +less than 1 + + align:start position:0% +less than 1 + + + align:start position:0% +less than 1 +37,6 + + align:start position:0% +37,6 + + + align:start position:0% +37,6 +48 you have no chance to go home + + align:start position:0% +48 you have no chance to go home + + + align:start position:0% +48 you have no chance to go home +happy so you know my mother-in-law is + + align:start position:0% +happy so you know my mother-in-law is + + + align:start position:0% +happy so you know my mother-in-law is +telling me the story about how she + + align:start position:0% +telling me the story about how she + + + align:start position:0% +telling me the story about how she +always goes home happy and I'm saying no + + align:start position:0% +always goes home happy and I'm saying no + + + align:start position:0% +always goes home happy and I'm saying no +no wait a minute you can't you never + + align:start position:0% +no wait a minute you can't you never + + + align:start position:0% +no wait a minute you can't you never +went home Happy let's be honest right it + + align:start position:0% +went home Happy let's be honest right it + + + align:start position:0% +went home Happy let's be honest right it +can't be she goes no no no no it's true + + align:start position:0% +can't be she goes no no no no it's true + + + align:start position:0% +can't be she goes no no no no it's true +and I go no look look there's a + + align:start position:0% +and I go no look look there's a + + + align:start position:0% +and I go no look look there's a +mathematical proof I have a proof I can + + align:start position:0% +mathematical proof I have a proof I can + + + align:start position:0% +mathematical proof I have a proof I can +show you my proof very unlikely you go + + align:start position:0% +show you my proof very unlikely you go + + + align:start position:0% +show you my proof very unlikely you go +home a winter you know so somehow she's + + align:start position:0% +home a winter you know so somehow she's + + + align:start position:0% +home a winter you know so somehow she's +not very impressed with the mathematical + + align:start position:0% +not very impressed with the mathematical + + + align:start position:0% +not very impressed with the mathematical +proof you know and she keeps insisting + + align:start position:0% +proof you know and she keeps insisting + + + align:start position:0% +proof you know and she keeps insisting +and I keep trying to show her the proof + + align:start position:0% +and I keep trying to show her the proof + + + align:start position:0% +and I keep trying to show her the proof +and uh anyway I hope I'll have more luck + + align:start position:0% +and uh anyway I hope I'll have more luck + + + align:start position:0% +and uh anyway I hope I'll have more luck +with you guys today in showing you the + + align:start position:0% +with you guys today in showing you the + + + align:start position:0% +with you guys today in showing you the +proof that the chance you go home happy + + align:start position:0% +proof that the chance you go home happy + + + align:start position:0% +proof that the chance you go home happy +here is very very small now in the end I + + align:start position:0% +here is very very small now in the end I + + + align:start position:0% +here is very very small now in the end I +didn't convince her but uh we'll we'll + + align:start position:0% +didn't convince her but uh we'll we'll + + + align:start position:0% +didn't convince her but uh we'll we'll +see how we do here + + align:start position:0% +see how we do here + + + align:start position:0% +see how we do here +today now in order to see why this + + align:start position:0% +today now in order to see why this + + + align:start position:0% +today now in order to see why this +probability is so stunningly small we + + align:start position:0% +probability is so stunningly small we + + + align:start position:0% +probability is so stunningly small we +just never guess it's it's that low + + align:start position:0% +just never guess it's it's that low + + + align:start position:0% +just never guess it's it's that low +we've got to learn about random walks + + align:start position:0% +we've got to learn about random walks + + + align:start position:0% +we've got to learn about random walks +and they come up in all sorts of + + align:start position:0% +and they come up in all sorts of + + + align:start position:0% +and they come up in all sorts of +applications in fact uh you know page + + align:start position:0% +applications in fact uh you know page + + + align:start position:0% +applications in fact uh you know page +rank you know they got Google started + + align:start position:0% +rank you know they got Google started + + + align:start position:0% +rank you know they got Google started +it's all based on a random walk through + + align:start position:0% +it's all based on a random walk through + + + align:start position:0% +it's all based on a random walk through +the web or through the links on web + + align:start position:0% +the web or through the links on web + + + align:start position:0% +the web or through the links on web +pages on that graph uh now for the + + align:start position:0% +pages on that graph uh now for the + + + align:start position:0% +pages on that graph uh now for the +gambling problem we're going to look at + + align:start position:0% +gambling problem we're going to look at + + + align:start position:0% +gambling problem we're going to look at +a very special case probably the + + align:start position:0% +a very special case probably the + + + align:start position:0% +a very special case probably the +simplest case of Random walk and that's + + align:start position:0% +simplest case of Random walk and that's + + + align:start position:0% +simplest case of Random walk and that's +a one-dimensional random walk in a + + align:start position:0% +a one-dimensional random walk in a + + + align:start position:0% +a one-dimensional random walk in a +one-dimensional random walk there's some + + align:start position:0% +one-dimensional random walk there's some + + + align:start position:0% +one-dimensional random walk there's some +value say the number of dollars you've + + align:start position:0% +value say the number of dollars you've + + + align:start position:0% +value say the number of dollars you've +got you know in your pocket and this + + align:start position:0% +got you know in your pocket and this + + + align:start position:0% +got you know in your pocket and this +value can go up or go down or stay the + + align:start position:0% +value can go up or go down or stay the + + + align:start position:0% +value can go up or go down or stay the +same each time you do something like + + align:start position:0% +same each time you do something like + + + align:start position:0% +same each time you do something like +make a bet and each of these happens + + align:start position:0% +make a bet and each of these happens + + + align:start position:0% +make a bet and each of these happens +with a certain + + align:start position:0% +with a certain + + + align:start position:0% +with a certain +probability now in this case you either + + align:start position:0% +probability now in this case you either + + + align:start position:0% +probability now in this case you either +go up by one or you go down by one and + + align:start position:0% +go up by one or you go down by one and + + + align:start position:0% +go up by one or you go down by one and +you can't stay the same every bet you + + align:start position:0% +you can't stay the same every bet you + + + align:start position:0% +you can't stay the same every bet you +win a buck or you lose lose a buck so + + align:start position:0% +win a buck or you lose lose a buck so + + + align:start position:0% +win a buck or you lose lose a buck so +it's really a special case and we can + + align:start position:0% +it's really a special case and we can + + + align:start position:0% +it's really a special case and we can +diagram it as follows so we can put time + + align:start position:0% +diagram it as follows so we can put time + + + align:start position:0% +diagram it as follows so we can put time +or the number of bets on this + + align:start position:0% + + + + align:start position:0% + +axis and we can put the number of + + align:start position:0% +axis and we can put the number of + + + align:start position:0% +axis and we can put the number of +dollars on this + + align:start position:0% + + + + align:start position:0% + +axis now in this case we start with + + align:start position:0% +axis now in this case we start with + + + align:start position:0% +axis now in this case we start with +n and we might win the first bet so we + + align:start position:0% +n and we might win the first bet so we + + + align:start position:0% +n and we might win the first bet so we +go to n plus one we might lose lose a + + align:start position:0% +go to n plus one we might lose lose a + + + align:start position:0% +go to n plus one we might lose lose a +bit might lose again could win the next + + align:start position:0% +bit might lose again could win the next + + + align:start position:0% +bit might lose again could win the next +one lose win lose lose so this + + align:start position:0% +one lose win lose lose so this + + + align:start position:0% +one lose win lose lose so this +corresponds to a string win lose lose + + align:start position:0% +corresponds to a string win lose lose + + + align:start position:0% +corresponds to a string win lose lose +lose lose win lose win lose + + align:start position:0% +lose lose win lose win lose + + + align:start position:0% +lose lose win lose win lose +lose + + align:start position:0% +lose + + + align:start position:0% +lose +lose okay and when we win we go up a + + align:start position:0% +lose okay and when we win we go up a + + + align:start position:0% +lose okay and when we win we go up a +dollar and we lose we go down a dollar + + align:start position:0% + + + + align:start position:0% + +and it's called onedimensional because + + align:start position:0% +and it's called onedimensional because + + + align:start position:0% +and it's called onedimensional because +there's just one thing that's changing + + align:start position:0% +there's just one thing that's changing + + + align:start position:0% +there's just one thing that's changing +you're going up and down there now the + + align:start position:0% +you're going up and down there now the + + + align:start position:0% +you're going up and down there now the +probability of going up is + + align:start position:0% +probability of going up is + + + align:start position:0% +probability of going up is +p and that's no matter what happened + + align:start position:0% +p and that's no matter what happened + + + align:start position:0% +p and that's no matter what happened +before it's a memoryless independent + + align:start position:0% +before it's a memoryless independent + + + align:start position:0% +before it's a memoryless independent +system the probability you win your I + + align:start position:0% +system the probability you win your I + + + align:start position:0% +system the probability you win your I +bet has nothing to do is totally + + align:start position:0% +bet has nothing to do is totally + + + align:start position:0% +bet has nothing to do is totally +independent mutually independent of all + + align:start position:0% +independent mutually independent of all + + + align:start position:0% +independent mutually independent of all +the other bets that took place + + align:start position:0% +the other bets that took place + + + align:start position:0% +the other bets that took place +before all right so let's write that + + align:start position:0% +before all right so let's write that + + + align:start position:0% +before all right so let's write that +down + + align:start position:0% + + + + align:start position:0% + +so the probability of an up + + align:start position:0% + + + + align:start position:0% + +move is p the probability of a Down + + align:start position:0% +move is p the probability of a Down + + + align:start position:0% +move is p the probability of a Down +move is 1 minus p and these are mutually + + align:start position:0% + + + + align:start position:0% + +independent of past + + align:start position:0% + + + + align:start position:0% + +moves now when you have a random walk + + align:start position:0% +moves now when you have a random walk + + + align:start position:0% +moves now when you have a random walk +with a moves are mutually independent it + + align:start position:0% +with a moves are mutually independent it + + + align:start position:0% +with a moves are mutually independent it +has a special name it's called a + + align:start position:0% + + + + align:start position:0% + +Martingale you know there's not all + + align:start position:0% +Martingale you know there's not all + + + align:start position:0% +Martingale you know there's not all +random walks don't have to have mutually + + align:start position:0% +random walks don't have to have mutually + + + align:start position:0% +random walks don't have to have mutually +independent steps like say you're + + align:start position:0% +independent steps like say you're + + + align:start position:0% +independent steps like say you're +looking about winning and losing a + + align:start position:0% +looking about winning and losing a + + + align:start position:0% +looking about winning and losing a +baseball game in a series we looked at a + + align:start position:0% +baseball game in a series we looked at a + + + align:start position:0% +baseball game in a series we looked at a +scenario where if you lost yesterday + + align:start position:0% +scenario where if you lost yesterday + + + align:start position:0% +scenario where if you lost yesterday +you're feeling lousy more likely to lose + + align:start position:0% +you're feeling lousy more likely to lose + + + align:start position:0% +you're feeling lousy more likely to lose +today not true in the gambling case here + + align:start position:0% +today not true in the gambling case here + + + align:start position:0% +today not true in the gambling case here +it's mutually independent and that's the + + align:start position:0% +it's mutually independent and that's the + + + align:start position:0% +it's mutually independent and that's the +only case we're going to study for + + align:start position:0% +only case we're going to study for + + + align:start position:0% +only case we're going to study for +random + + align:start position:0% +random + + + align:start position:0% +random +walks + + align:start position:0% +walks + + + align:start position:0% +walks +now if p is not a + + align:start position:0% +now if p is not a + + + align:start position:0% +now if p is not a +half the random walk is said to be + + align:start position:0% + + + + align:start position:0% + +biased and that's what happens in the + + align:start position:0% +biased and that's what happens in the + + + align:start position:0% +biased and that's what happens in the +casino it's biased in favor of the + + align:start position:0% +casino it's biased in favor of the + + + align:start position:0% +casino it's biased in favor of the +house if P equals a + + align:start position:0% +house if P equals a + + + align:start position:0% +house if P equals a +half then the random walk is + + align:start position:0% + + + + align:start position:0% + +unbiased + + align:start position:0% +unbiased + + + align:start position:0% +unbiased +now in this particular case that we're + + align:start position:0% +now in this particular case that we're + + + align:start position:0% +now in this particular case that we're +looking at we have boundaries on the + + align:start position:0% +looking at we have boundaries on the + + + align:start position:0% +looking at we have boundaries on the +random walk there's a boundary at zero + + align:start position:0% +random walk there's a boundary at zero + + + align:start position:0% +random walk there's a boundary at zero +because you go home broke if you lost + + align:start position:0% +because you go home broke if you lost + + + align:start position:0% +because you go home broke if you lost +everything if the random walk ever hits + + align:start position:0% +everything if the random walk ever hits + + + align:start position:0% +everything if the random walk ever hits +zero dollars you're done and we're also + + align:start position:0% +zero dollars you're done and we're also + + + align:start position:0% +zero dollars you're done and we're also +going to put a + + align:start position:0% + + + + align:start position:0% + +boundary at n plus + + align:start position:0% + + + + align:start position:0% + +M okay so I'm going to have a + + align:start position:0% +M okay so I'm going to have a + + + align:start position:0% +M okay so I'm going to have a +boundary here + + align:start position:0% +boundary here + + + align:start position:0% +boundary here +so that if I win MLL here I stop and I + + align:start position:0% +so that if I win MLL here I stop and I + + + align:start position:0% +so that if I win MLL here I stop and I +go home happy if the random walk ever + + align:start position:0% +go home happy if the random walk ever + + + align:start position:0% +go home happy if the random walk ever +goes here then I + + align:start position:0% +goes here then I + + + align:start position:0% +goes here then I +stop those are called boundary + + align:start position:0% +stop those are called boundary + + + align:start position:0% +stop those are called boundary +conditions for the + + align:start position:0% +conditions for the + + + align:start position:0% +conditions for the +walk and what we want to do is analyze + + align:start position:0% +walk and what we want to do is analyze + + + align:start position:0% +walk and what we want to do is analyze +the probability that we hit that top + + align:start position:0% +the probability that we hit that top + + + align:start position:0% +the probability that we hit that top +boundary before we hit the bottom + + align:start position:0% +boundary before we hit the bottom + + + align:start position:0% +boundary before we hit the bottom +boundary so we're going to Define that + + align:start position:0% +boundary so we're going to Define that + + + align:start position:0% +boundary so we're going to Define that +event to be W star + + align:start position:0% +event to be W star + + + align:start position:0% +event to be W star +W star is the + + align:start position:0% +W star is the + + + align:start position:0% +W star is the +event that the random walk + + align:start position:0% + + + + align:start position:0% + +hits T which is n plus + + align:start position:0% + + + + align:start position:0% + +M + + align:start position:0% +M + + + align:start position:0% +M +before it hits + + align:start position:0% + + + + align:start position:0% + +zero in other words you go home happy + + align:start position:0% +zero in other words you go home happy + + + align:start position:0% +zero in other words you go home happy +without going + + align:start position:0% +without going + + + align:start position:0% +without going +broke let's also Define d to be the + + align:start position:0% +broke let's also Define d to be the + + + align:start position:0% +broke let's also Define d to be the +number number of dollars at the start + + align:start position:0% +number number of dollars at the start + + + align:start position:0% +number number of dollars at the start +and this is just going to be n in our + + align:start position:0% + + + + align:start position:0% + +case we're interested + + align:start position:0% +case we're interested + + + align:start position:0% +case we're interested +in call it X subn is the + + align:start position:0% +in call it X subn is the + + + align:start position:0% +in call it X subn is the +probability that we go home + + align:start position:0% +probability that we go home + + + align:start position:0% +probability that we go home +Happy given we started with + + align:start position:0% + + + + align:start position:0% + +n all right that's a function of n so + + align:start position:0% +n all right that's a function of n so + + + align:start position:0% +n all right that's a function of n so +we'll make a variable called xn and we + + align:start position:0% +we'll make a variable called xn and we + + + align:start position:0% +we'll make a variable called xn and we +want to know what that probability is + + align:start position:0% +want to know what that probability is + + + align:start position:0% +want to know what that probability is +and of course the more you come with + + align:start position:0% +and of course the more you come with + + + align:start position:0% +and of course the more you come with +you'd think it's a higher chance of + + align:start position:0% +you'd think it's a higher chance of + + + align:start position:0% +you'd think it's a higher chance of +winning the more you have in your pocket + + align:start position:0% +winning the more you have in your pocket + + + align:start position:0% +winning the more you have in your pocket +because you can play for more so the + + align:start position:0% +because you can play for more so the + + + align:start position:0% +because you can play for more so the +goal is to figure this + + align:start position:0% +goal is to figure this + + + align:start position:0% +goal is to figure this +out now to do this we could use the tree + + align:start position:0% +out now to do this we could use the tree + + + align:start position:0% +out now to do this we could use the tree +method but it gets pretty + + align:start position:0% +method but it gets pretty + + + align:start position:0% +method but it gets pretty +complicated because the sample space is + + align:start position:0% +complicated because the sample space is + + + align:start position:0% +complicated because the sample space is +the sample space of all one law + + align:start position:0% +the sample space of all one law + + + align:start position:0% +the sample space of all one law +sequences and how big is that sample + + align:start position:0% +sequences and how big is that sample + + + align:start position:0% +sequences and how big is that sample +space + + align:start position:0% + + + + align:start position:0% + +infinite I could play Forever all right + + align:start position:0% +infinite I could play Forever all right + + + align:start position:0% +infinite I could play Forever all right +now it turns out the probability of + + align:start position:0% +now it turns out the probability of + + + align:start position:0% +now it turns out the probability of +playing forever is zero and we won't + + align:start position:0% +playing forever is zero and we won't + + + align:start position:0% +playing forever is zero and we won't +prove that but there are an infinite + + align:start position:0% +prove that but there are an infinite + + + align:start position:0% +prove that but there are an infinite +number of sample points so doing the + + align:start position:0% +number of sample points so doing the + + + align:start position:0% +number of sample points so doing the +tree methods a little complicated when + + align:start position:0% +tree methods a little complicated when + + + align:start position:0% +tree methods a little complicated when +it's + + align:start position:0% +it's + + + align:start position:0% +it's +infinite um so what we're going to do is + + align:start position:0% +infinite um so what we're going to do is + + + align:start position:0% +infinite um so what we're going to do is +use some of the theorems we proved over + + align:start position:0% +use some of the theorems we proved over + + + align:start position:0% +use some of the theorems we proved over +the last few weeks and set up a + + align:start position:0% +the last few weeks and set up a + + + align:start position:0% +the last few weeks and set up a +recurrence to find this + + align:start position:0% +recurrence to find this + + + align:start position:0% +recurrence to find this +probability + + align:start position:0% + + + + align:start position:0% + +now I'm going to tell you what the + + align:start position:0% +now I'm going to tell you what the + + + align:start position:0% +now I'm going to tell you what the +recurrence is and then prove that that's + + align:start position:0% +recurrence is and then prove that that's + + + align:start position:0% +recurrence is and then prove that that's +right so I + + align:start position:0% +right so I + + + align:start position:0% +right so I +claim that + + align:start position:0% +claim that + + + align:start position:0% +claim that +xn is zero zero probability if we start + + align:start position:0% +xn is zero zero probability if we start + + + align:start position:0% +xn is zero zero probability if we start +with n with zero + + align:start position:0% +with n with zero + + + align:start position:0% +with n with zero +dollars it's one if we start with + + align:start position:0% +dollars it's one if we start with + + + align:start position:0% +dollars it's one if we start with +t and it's p * X x n + + align:start position:0% +t and it's p * X x n + + + align:start position:0% +t and it's p * X x n +-1 + 1 - P xn + + + align:start position:0% +-1 + 1 - P xn + + + + align:start position:0% +-1 + 1 - P xn + +1 if we start with + + align:start position:0% +1 if we start with + + + align:start position:0% +1 if we start with +between um zero and + + align:start position:0% + + + + align:start position:0% + +T all right so that's what I claim xn is + + align:start position:0% +T all right so that's what I claim xn is + + + align:start position:0% +T all right so that's what I claim xn is +and it's of course a recursion that I've + + align:start position:0% +and it's of course a recursion that I've + + + align:start position:0% +and it's of course a recursion that I've +set up here so let's see why that's the + + align:start position:0% + + + + align:start position:0% + +case Okay so let's check the zero case + + align:start position:0% +case Okay so let's check the zero case + + + align:start position:0% +case Okay so let's check the zero case +x0 is the probability we go home a + + align:start position:0% +x0 is the probability we go home a + + + align:start position:0% +x0 is the probability we go home a +winner given we started with + + align:start position:0% + + + + align:start position:0% + +0 right why is that + + align:start position:0% + + + + align:start position:0% + +zero what's + + align:start position:0% + + + + align:start position:0% + +that yeah you you started broke you + + align:start position:0% +that yeah you you started broke you + + + align:start position:0% +that yeah you you started broke you +never get off the ground because you + + align:start position:0% +never get off the ground because you + + + align:start position:0% +never get off the ground because you +quit as soon as you have zero dollars so + + align:start position:0% +quit as soon as you have zero dollars so + + + align:start position:0% +quit as soon as you have zero dollars so +you have no chance + + align:start position:0% +you have no chance + + + align:start position:0% +you have no chance +to + + align:start position:0% +to + + + align:start position:0% +to +win because you're broke to + + align:start position:0% +win because you're broke to + + + align:start position:0% +win because you're broke to +start right let's check the next case + + align:start position:0% +start right let's check the next case + + + align:start position:0% +start right let's check the next case +XT case n equals T is the probability + + align:start position:0% +XT case n equals T is the probability + + + align:start position:0% +XT case n equals T is the probability +you go home a winner given that you + + align:start position:0% +you go home a winner given that you + + + align:start position:0% +you go home a winner given that you +started with t + + align:start position:0% +started with t + + + align:start position:0% +started with t +do why is that + + align:start position:0% +do why is that + + + align:start position:0% +do why is that +one why is that certain sort of from the + + align:start position:0% +one why is that certain sort of from the + + + align:start position:0% +one why is that certain sort of from the +definition you already have your money + + align:start position:0% +definition you already have your money + + + align:start position:0% +definition you already have your money +you already hit the top boundary because + + align:start position:0% +you already hit the top boundary because + + + align:start position:0% +you already hit the top boundary because +you started there remember you quit and + + align:start position:0% +you started there remember you quit and + + + align:start position:0% +you started there remember you quit and +you're happy go home happy if you hit + + align:start position:0% +you're happy go home happy if you hit + + + align:start position:0% +you're happy go home happy if you hit +T all right so you're guaranteed to go + + align:start position:0% +T all right so you're guaranteed to go + + + align:start position:0% +T all right so you're guaranteed to go +home happy because you never make any + + align:start position:0% +home happy because you never make any + + + align:start position:0% +home happy because you never make any +bets you started with all the money you + + align:start position:0% +bets you started with all the money you + + + align:start position:0% +bets you started with all the money you +needed to go home happy all right then + + align:start position:0% +needed to go home happy all right then + + + align:start position:0% +needed to go home happy all right then +we have the interesting + + align:start position:0% + + + + align:start position:0% + +case where you start with between zero + + align:start position:0% +case where you start with between zero + + + align:start position:0% +case where you start with between zero +and T and now you're going to make some + + align:start position:0% +and T and now you're going to make some + + + align:start position:0% +and T and now you're going to make some +bets and then xn is the probability just + + align:start position:0% +bets and then xn is the probability just + + + align:start position:0% +bets and then xn is the probability just +the definition of going home Happy + + align:start position:0% +the definition of going home Happy + + + align:start position:0% +the definition of going home Happy +I.E winning T having T dollars if you + + align:start position:0% +I.E winning T having T dollars if you + + + align:start position:0% +I.E winning T having T dollars if you +start with + + align:start position:0% +start with + + + align:start position:0% +start with +n now there's two cases to analyze this + + align:start position:0% +n now there's two cases to analyze this + + + align:start position:0% +n now there's two cases to analyze this +based on what happens in the first bet + + align:start position:0% +based on what happens in the first bet + + + align:start position:0% +based on what happens in the first bet +you could win it or you could lose it + + align:start position:0% +you could win it or you could lose it + + + align:start position:0% +you could win it or you could lose it +and then we're going to + + align:start position:0% +and then we're going to + + + align:start position:0% +and then we're going to +recurse so we're going to + + align:start position:0% + + + + align:start position:0% + +Define e to be the + + align:start position:0% +Define e to be the + + + align:start position:0% +Define e to be the +event that you win the first + + align:start position:0% +event that you win the first + + + align:start position:0% +event that you win the first +bet + + align:start position:0% +bet + + + align:start position:0% +bet +and + + align:start position:0% +and + + + align:start position:0% +and +ebar is the + + align:start position:0% +ebar is the + + + align:start position:0% +ebar is the +event that you lose the first + + align:start position:0% + + + + align:start position:0% + +bet all right now by the theorem of + + align:start position:0% +bet all right now by the theorem of + + + align:start position:0% +bet all right now by the theorem of +total probability which we did in + + align:start position:0% +total probability which we did in + + + align:start position:0% +total probability which we did in +recitation maybe a couple weeks ago we + + align:start position:0% +recitation maybe a couple weeks ago we + + + align:start position:0% +recitation maybe a couple weeks ago we +can rewrite this depending on whether e + + align:start position:0% +can rewrite this depending on whether e + + + align:start position:0% +can rewrite this depending on whether e +happened or the complement of + + align:start position:0% +happened or the complement of + + + align:start position:0% +happened or the complement of +happened and you get that the + + align:start position:0% +happened and you get that the + + + align:start position:0% +happened and you get that the +probability is simply the probab of + + align:start position:0% +probability is simply the probab of + + + align:start position:0% +probability is simply the probab of +going home + + align:start position:0% +going home + + + align:start position:0% +going home +happy and winning the first bet times + + align:start position:0% +happy and winning the first bet times + + + align:start position:0% +happy and winning the first bet times +the probab whoops and I got to put the + + align:start position:0% +the probab whoops and I got to put the + + + align:start position:0% +the probab whoops and I got to put the +conditioning in that doesn't go + + align:start position:0% + + + + align:start position:0% + +away so I'm breaking into two cases the + + align:start position:0% +away so I'm breaking into two cases the + + + align:start position:0% +away so I'm breaking into two cases the +first one is you win the first bet given + + align:start position:0% +first one is you win the first bet given + + + align:start position:0% +first one is you win the first bet given +D equals + + align:start position:0% +D equals + + + align:start position:0% +D equals +n and the case where you lose the first + + align:start position:0% + + + + align:start position:0% + +bet given equal + + align:start position:0% +bet given equal + + + align:start position:0% +bet given equal +n any questions + + align:start position:0% +n any questions + + + align:start position:0% +n any questions +here probability of going home Happy + + align:start position:0% +here probability of going home Happy + + + align:start position:0% +here probability of going home Happy +given you start + + align:start position:0% +given you start + + + align:start position:0% +given you start +with1 is the probability of going home + + align:start position:0% +with1 is the probability of going home + + + align:start position:0% +with1 is the probability of going home +happy and winning the first bet + + align:start position:0% +happy and winning the first bet + + + align:start position:0% +happy and winning the first bet +oops Yeah uh given D equals n plus the + + align:start position:0% +oops Yeah uh given D equals n plus the + + + align:start position:0% +oops Yeah uh given D equals n plus the +probability of going home happy and + + align:start position:0% +probability of going home happy and + + + align:start position:0% +probability of going home happy and +losing the first bet given D equals n + + align:start position:0% +losing the first bet given D equals n + + + align:start position:0% +losing the first bet given D equals n +just those are the two + + align:start position:0% +just those are the two + + + align:start position:0% +just those are the two +cases now I can use the definition of + + align:start position:0% +cases now I can use the definition of + + + align:start position:0% +cases now I can use the definition of +conditional probability to rewrite + + align:start position:0% +conditional probability to rewrite + + + align:start position:0% +conditional probability to rewrite +these this is the probability we got two + + align:start position:0% +these this is the probability we got two + + + align:start position:0% +these this is the probability we got two +events that the first one + + align:start position:0% +events that the first one + + + align:start position:0% +events that the first one +happens given D equals + + align:start position:0% +happens given D equals + + + align:start position:0% +happens given D equals +n times the probability the second one + + align:start position:0% +n times the probability the second one + + + align:start position:0% +n times the probability the second one +happens given that the first one + + align:start position:0% +happens given that the first one + + + align:start position:0% +happens given that the first one +happened and D equals + + align:start position:0% +happened and D equals + + + align:start position:0% +happened and D equals +n all right this is just the definition + + align:start position:0% +n all right this is just the definition + + + align:start position:0% +n all right this is just the definition +of conditional probability when I got an + + align:start position:0% +of conditional probability when I got an + + + align:start position:0% +of conditional probability when I got an +intersection of events here the + + align:start position:0% +intersection of events here the + + + align:start position:0% +intersection of events here the +probability of both happening is the + + align:start position:0% +probability of both happening is the + + + align:start position:0% +probability of both happening is the +probability of the first happening times + + align:start position:0% +probability of the first happening times + + + align:start position:0% +probability of the first happening times +the probability of the second happening + + align:start position:0% +the probability of the second happening + + + align:start position:0% +the probability of the second happening +given that the first happened and of + + align:start position:0% +given that the first happened and of + + + align:start position:0% +given that the first happened and of +course everything is in this universe of + + align:start position:0% +course everything is in this universe of + + + align:start position:0% +course everything is in this universe of +D equals + + align:start position:0% +D equals + + + align:start position:0% +D equals +n all right so I've used it in a little + + align:start position:0% +n all right so I've used it in a little + + + align:start position:0% +n all right so I've used it in a little +Just A Different Twist from when we had + + align:start position:0% +Just A Different Twist from when we had + + + align:start position:0% +Just A Different Twist from when we had +it before same thing over here this now + + align:start position:0% +it before same thing over here this now + + + align:start position:0% +it before same thing over here this now +is the probability of e Prime given D + + align:start position:0% +is the probability of e Prime given D + + + align:start position:0% +is the probability of e Prime given D +equals n times the probability of w star + + align:start position:0% +equals n times the probability of w star + + + align:start position:0% +equals n times the probability of w star +winning going home Happy + + align:start position:0% +winning going home Happy + + + align:start position:0% +winning going home Happy +given that you lost the first bet and D + + align:start position:0% +given that you lost the first bet and D + + + align:start position:0% +given that you lost the first bet and D +equals + + align:start position:0% +equals + + + align:start position:0% +equals +n + + align:start position:0% +n + + + align:start position:0% +n +that's D equals n + + align:start position:0% +that's D equals n + + + align:start position:0% +that's D equals n +there right so it looks like it's gotten + + align:start position:0% +there right so it looks like it's gotten + + + align:start position:0% +there right so it looks like it's gotten +more complicated but now we can start + + align:start position:0% +more complicated but now we can start + + + align:start position:0% +more complicated but now we can start +simplifying what's the probability of + + align:start position:0% +simplifying what's the probability of + + + align:start position:0% +simplifying what's the probability of +winning the first bet given that you + + align:start position:0% +winning the first bet given that you + + + align:start position:0% +winning the first bet given that you +started + + align:start position:0% + + + + align:start position:0% + +with1 + + align:start position:0% +with1 + + + align:start position:0% +with1 +P in fact does this have anything to do + + align:start position:0% +P in fact does this have anything to do + + + align:start position:0% +P in fact does this have anything to do +with the probability of winning the + + align:start position:0% +with the probability of winning the + + + align:start position:0% +with the probability of winning the +first + + align:start position:0% +first + + + align:start position:0% +first +bet no this is just + + align:start position:0% + + + + align:start position:0% + +P okay uh um now what about this + + align:start position:0% +P okay uh um now what about this + + + align:start position:0% +P okay uh um now what about this +thing I am conditioning on winning the + + align:start position:0% +thing I am conditioning on winning the + + + align:start position:0% +thing I am conditioning on winning the +first + + align:start position:0% + + + + align:start position:0% + +bet + + align:start position:0% +bet + + + align:start position:0% +bet +given and I start with + + align:start position:0% + + + + align:start position:0% + +nll okay what's another way of + + align:start position:0% +nll okay what's another way of + + + align:start position:0% +nll okay what's another way of +expressing I won the first bet and I + + align:start position:0% +expressing I won the first bet and I + + + align:start position:0% +expressing I won the first bet and I +started with + + align:start position:0% +started with + + + align:start position:0% +started with +n + + align:start position:0% +n + + + align:start position:0% +n +yeah I now have n Plus $ going + + align:start position:0% +yeah I now have n Plus $ going + + + align:start position:0% +yeah I now have n Plus $ going +forward and because I have a Martingale + + align:start position:0% +forward and because I have a Martingale + + + align:start position:0% +forward and because I have a Martingale +and everything is mutually independent + + align:start position:0% +and everything is mutually independent + + + align:start position:0% +and everything is mutually independent +it's like the world starts all over + + align:start position:0% +it's like the world starts all over + + + align:start position:0% +it's like the world starts all over +again I'm now in a state with n plus1 + + align:start position:0% +again I'm now in a state with n plus1 + + + align:start position:0% +again I'm now in a state with n plus1 +and I want to know the + + align:start position:0% +and I want to know the + + + align:start position:0% +and I want to know the +probability that I go home Happy doesn't + + align:start position:0% +probability that I go home Happy doesn't + + + align:start position:0% +probability that I go home Happy doesn't +matter how I got the N + + align:start position:0% +matter how I got the N + + + align:start position:0% +matter how I got the N +plus1 it's just going forward I got n + + align:start position:0% +plus1 it's just going forward I got n + + + align:start position:0% +plus1 it's just going forward I got n +plus1 in my pocket I want to the + + align:start position:0% +plus1 in my pocket I want to the + + + align:start position:0% +plus1 in my pocket I want to the +probably to go and home happy so I reset + + align:start position:0% +probably to go and home happy so I reset + + + align:start position:0% +probably to go and home happy so I reset +to D equals n + + align:start position:0% +to D equals n + + + align:start position:0% +to D equals n +plus1 + + align:start position:0% +plus1 + + + align:start position:0% +plus1 +okay so I replace this with that because + + align:start position:0% +okay so I replace this with that because + + + align:start position:0% +okay so I replace this with that because +however long it took me to get there and + + align:start position:0% +however long it took me to get there and + + + align:start position:0% +however long it took me to get there and +all that stuff doesn't matter for this + + align:start position:0% +all that stuff doesn't matter for this + + + align:start position:0% +all that stuff doesn't matter for this +analysis it's all mutually + + align:start position:0% + + + + align:start position:0% + +independent okay probability of losing + + align:start position:0% +independent okay probability of losing + + + align:start position:0% +independent okay probability of losing +the first bet given that I started with + + align:start position:0% +the first bet given that I started with + + + align:start position:0% +the first bet given that I started with +N1 one minus P doesn't matter how much I + + align:start position:0% +N1 one minus P doesn't matter how much I + + + align:start position:0% +N1 one minus P doesn't matter how much I +started with and here I'm I want to know + + align:start position:0% +started with and here I'm I want to know + + + align:start position:0% +started with and here I'm I want to know +the probability of going home + + align:start position:0% +the probability of going home + + + align:start position:0% +the probability of going home +Happy + + align:start position:0% +Happy + + + align:start position:0% +Happy +given well if I lost the first bet and I + + align:start position:0% +given well if I lost the first bet and I + + + align:start position:0% +given well if I lost the first bet and I +started with n what have I + + align:start position:0% +started with n what have I + + + align:start position:0% +started with n what have I +got n minus + + align:start position:0% + + + + align:start position:0% + +one okay and doesn't matter how I got to + + align:start position:0% +one okay and doesn't matter how I got to + + + align:start position:0% +one okay and doesn't matter how I got to +n minus + + align:start position:0% +n minus + + + align:start position:0% +n minus +one okay well now this is going to get + + align:start position:0% +one okay well now this is going to get + + + align:start position:0% +one okay well now this is going to get +really + + align:start position:0% + + + + align:start position:0% + +simple what's another name for that + + align:start position:0% +simple what's another name for that + + + align:start position:0% +simple what's another name for that +expression xn + + + align:start position:0% + + + + align:start position:0% + +one and another name for this + + align:start position:0% +one and another name for this + + + align:start position:0% +one and another name for this +expression xn minus + + align:start position:0% + + + + align:start position:0% + +one okay so we Prov that xn equals pxn + + + align:start position:0% +one okay so we Prov that xn equals pxn + + + + align:start position:0% +one okay so we Prov that xn equals pxn + +1 + 1 - pxn minus one and that's what I + + align:start position:0% +1 + 1 - pxn minus one and that's what I + + + align:start position:0% +1 + 1 - pxn minus one and that's what I +claimed was true so we finished the + + align:start position:0% +claimed was true so we finished the + + + align:start position:0% +claimed was true so we finished the +proof any + + align:start position:0% +proof any + + + align:start position:0% +proof any +questions did I screw it + + align:start position:0% +questions did I screw it + + + align:start position:0% +questions did I screw it +up I + + align:start position:0% + + + + align:start position:0% + +claim probability of winning + + align:start position:0% +claim probability of winning + + + align:start position:0% +claim probability of winning +so let's see let's see if I have it + + align:start position:0% +so let's see let's see if I have it + + + align:start position:0% +so let's see let's see if I have it +wrong in here might screwed it up + + align:start position:0% +wrong in here might screwed it up + + + align:start position:0% +wrong in here might screwed it up +because I think I proved it's n+ one + + align:start position:0% +because I think I proved it's n+ one + + + align:start position:0% +because I think I proved it's n+ one +right yep sure enough I think this is a + + align:start position:0% +right yep sure enough I think this is a + + + align:start position:0% +right yep sure enough I think this is a +plus one that's a minus one yeah always + + align:start position:0% +plus one that's a minus one yeah always + + + align:start position:0% +plus one that's a minus one yeah always +good to check that you proved what you + + align:start position:0% +good to check that you proved what you + + + align:start position:0% +good to check that you proved what you +said you were going to prove so what I + + align:start position:0% +said you were going to prove so what I + + + align:start position:0% +said you were going to prove so what I +said I needed to change this that's what + + align:start position:0% +said I needed to change this that's what + + + align:start position:0% +said I needed to change this that's what +I + + align:start position:0% + + + + align:start position:0% + +proved + + align:start position:0% +proved + + + align:start position:0% +proved +okay any other questions that was a + + align:start position:0% +okay any other questions that was a + + + align:start position:0% +okay any other questions that was a +pretty important + + align:start position:0% +pretty important + + + align:start position:0% +pretty important +question all right + + align:start position:0% +question all right + + + align:start position:0% +question all right +so we have a recurrence for xn now it's + + align:start position:0% +so we have a recurrence for xn now it's + + + align:start position:0% +so we have a recurrence for xn now it's +a little funny looking at first because + + align:start position:0% +a little funny looking at first because + + + align:start position:0% +a little funny looking at first because +normally with recurrences xn would + + align:start position:0% +normally with recurrences xn would + + + align:start position:0% +normally with recurrences xn would +depend on x sub I that are smaller I are + + align:start position:0% +depend on x sub I that are smaller I are + + + align:start position:0% +depend on x sub I that are smaller I are +smaller than n so it looks a little + + align:start position:0% +smaller than n so it looks a little + + + align:start position:0% +smaller than n so it looks a little +wacky but is that a + + align:start position:0% + + + + align:start position:0% + +problem I can just solve for xn plus one + + align:start position:0% +problem I can just solve for xn plus one + + + align:start position:0% +problem I can just solve for xn plus one +just subtract this and put it over there + + align:start position:0% +just subtract this and put it over there + + + align:start position:0% +just subtract this and put it over there +all right so let's do + + align:start position:0% + + + + align:start position:0% + +that okay so if I bring if I solve for + + align:start position:0% +that okay so if I bring if I solve for + + + align:start position:0% +that okay so if I bring if I solve for +xn plus one up there or put pxn plus1 on + + align:start position:0% +xn plus one up there or put pxn plus1 on + + + align:start position:0% +xn plus one up there or put pxn plus1 on +its own side I get P xn + 1 + + align:start position:0% +its own side I get P xn + 1 + + + align:start position:0% +its own side I get P xn + 1 +- + + align:start position:0% +- + + + align:start position:0% +- +xn + 1 - + + align:start position:0% +xn + 1 - + + + align:start position:0% +xn + 1 - +P xn - one equals 0 and I know that x0 + + align:start position:0% +P xn - one equals 0 and I know that x0 + + + align:start position:0% +P xn - one equals 0 and I know that x0 +is0 and I know that XT equals + + align:start position:0% + + + + align:start position:0% + +1 now what type of recurrence is + + align:start position:0% + + + + align:start position:0% + +this linear good so it's a linear + + align:start position:0% +this linear good so it's a linear + + + align:start position:0% +this linear good so it's a linear +recurrence and what type of linear + + align:start position:0% +recurrence and what type of linear + + + align:start position:0% +recurrence and what type of linear +recurrence is it + + align:start position:0% +recurrence is it + + + align:start position:0% +recurrence is it +homogeneous that's the best case simple + + align:start position:0% +homogeneous that's the best case simple + + + align:start position:0% +homogeneous that's the best case simple +case that's good the boundy conditions + + align:start position:0% +case that's good the boundy conditions + + + align:start position:0% +case that's good the boundy conditions +are a little weird because the + + align:start position:0% +are a little weird because the + + + align:start position:0% +are a little weird because the +recurrences we all saw before you know + + align:start position:0% +recurrences we all saw before you know + + + align:start position:0% +recurrences we all saw before you know +if we had two boundary conditions it + + align:start position:0% +if we had two boundary conditions it + + + align:start position:0% +if we had two boundary conditions it +would be x0 and X1 here it's x0 and XT + + align:start position:0% +would be x0 and X1 here it's x0 and XT + + + align:start position:0% +would be x0 and X1 here it's x0 and XT +but all you need or two doesn't matter + + align:start position:0% +but all you need or two doesn't matter + + + align:start position:0% +but all you need or two doesn't matter +where they + + align:start position:0% +where they + + + align:start position:0% +where they +are all right so how do I solve that + + align:start position:0% +are all right so how do I solve that + + + align:start position:0% +are all right so how do I solve that +thing what's the next thing I uh + + align:start position:0% +thing what's the next thing I uh + + + align:start position:0% +thing what's the next thing I uh +do what is + + align:start position:0% +do what is + + + align:start position:0% +do what is +it characteristic equation and what do + + align:start position:0% +it characteristic equation and what do + + + align:start position:0% +it characteristic equation and what do +you do with that + + align:start position:0% +you do with that + + + align:start position:0% +you do with that +equation solve it get the roots this + + align:start position:0% +equation solve it get the roots this + + + align:start position:0% +equation solve it get the roots this +will be good practice for the the final + + align:start position:0% +will be good practice for the the final + + + align:start position:0% +will be good practice for the the final +because you'll probably have to do + + align:start position:0% +because you'll probably have to do + + + align:start position:0% +because you'll probably have to do +something like this all right so that's + + align:start position:0% +something like this all right so that's + + + align:start position:0% +something like this all right so that's +the characteristic + + align:start position:0% + + + + align:start position:0% + +equation and what's the order of this + + align:start position:0% +equation and what's the order of this + + + align:start position:0% +equation and what's the order of this +equation the + + align:start position:0% + + + + align:start position:0% + +degree it's going to be it's going to + + align:start position:0% + + + + align:start position:0% + +be me two right I'm gonna have PR squar + + align:start position:0% +be me two right I'm gonna have PR squar + + + align:start position:0% +be me two right I'm gonna have PR squar +minus r + 1 - p is zero that's my + + align:start position:0% +minus r + 1 - p is zero that's my + + + align:start position:0% +minus r + 1 - p is zero that's my +characteristic + + align:start position:0% +characteristic + + + align:start position:0% +characteristic +equation all right remember that so I + + align:start position:0% +equation all right remember that so I + + + align:start position:0% +equation all right remember that so I +make this be the constant term then I + + align:start position:0% +make this be the constant term then I + + + align:start position:0% +make this be the constant term then I +have the first order term then the + + align:start position:0% +have the first order term then the + + + align:start position:0% +have the first order term then the +second order + + align:start position:0% +second order + + + align:start position:0% +second order +term all right now I solve + + align:start position:0% +term all right now I solve + + + align:start position:0% +term all right now I solve +it and that's easy for a second order + + align:start position:0% +it and that's easy for a second order + + + align:start position:0% +it and that's easy for a second order +equation one plus or minus the square Ro + + align:start position:0% +equation one plus or minus the square Ro + + + align:start position:0% +equation one plus or minus the square Ro +TK of 1 + + align:start position:0% +TK of 1 + + + align:start position:0% +TK of 1 +- 4 4 P 1 minus + + align:start position:0% +- 4 4 P 1 minus + + + align:start position:0% +- 4 4 P 1 minus +p over 2 + + align:start position:0% + + + + align:start position:0% + +p all right let's do + + align:start position:0% + + + + align:start position:0% + +that okay so this is one plus or minus + + align:start position:0% +that okay so this is one plus or minus + + + align:start position:0% +that okay so this is one plus or minus +Square < TK of 1 - 4 p + 4 p ^ + + align:start position:0% +Square < TK of 1 - 4 p + 4 p ^ + + + align:start position:0% +Square < TK of 1 - 4 p + 4 p ^ +2 over 2 + + align:start position:0% + + + + align:start position:0% + +p just using the quadratic formula and + + align:start position:0% + + + + align:start position:0% + +simplifying and it works out really + + align:start position:0% +simplifying and it works out really + + + align:start position:0% +simplifying and it works out really +nicely because that is the square root + + align:start position:0% +nicely because that is the square root + + + align:start position:0% +nicely because that is the square root +this is just 1 minus 2 + + align:start position:0% + + + + align:start position:0% + +p^2 so that's 1 plus or minus 1 - 2 p + + align:start position:0% +p^2 so that's 1 plus or minus 1 - 2 p + + + align:start position:0% +p^2 so that's 1 plus or minus 1 - 2 p +over 2 + + align:start position:0% +over 2 + + + align:start position:0% +over 2 +p and that + + align:start position:0% +p and that + + + align:start position:0% +p and that +is 2 - 2 p over 2 + + align:start position:0% +is 2 - 2 p over 2 + + + align:start position:0% +is 2 - 2 p over 2 +p + + align:start position:0% +p + + + align:start position:0% +p +or let's see one minus one cancels then + + align:start position:0% +or let's see one minus one cancels then + + + align:start position:0% +or let's see one minus one cancels then +one then minus minus 2 p is 2 p over 2 p + + align:start position:0% +one then minus minus 2 p is 2 p over 2 p + + + align:start position:0% +one then minus minus 2 p is 2 p over 2 p +so the answers the roots + + align:start position:0% +so the answers the roots + + + align:start position:0% +so the answers the roots +are divide by two on this one I get 1 + + align:start position:0% +are divide by two on this one I get 1 + + + align:start position:0% +are divide by two on this one I get 1 +minus p over p and + + align:start position:0% +minus p over p and + + + align:start position:0% +minus p over p and +one those are the + + align:start position:0% +one those are the + + + align:start position:0% +one those are the +roots + + align:start position:0% +roots + + + align:start position:0% +roots +okay are these roots Ro + + align:start position:0% +okay are these roots Ro + + + align:start position:0% +okay are these roots Ro +different do I have the case of a double + + align:start position:0% +different do I have the case of a double + + + align:start position:0% +different do I have the case of a double +root or the roots always + + align:start position:0% +root or the roots always + + + align:start position:0% +root or the roots always +different yeah they're usually different + + align:start position:0% +different yeah they're usually different + + + align:start position:0% +different yeah they're usually different +what's the case where these roots are + + align:start position:0% +what's the case where these roots are + + + align:start position:0% +what's the case where these roots are +the same 0 five which is sort of an + + align:start position:0% +the same 0 five which is sort of an + + + align:start position:0% +the same 0 five which is sort of an +interesting case in this game right + + align:start position:0% +interesting case in this game right + + + align:start position:0% +interesting case in this game right +because if P equals a half we have an + + align:start position:0% +because if P equals a half we have an + + + align:start position:0% +because if P equals a half we have an +unbiased random walk you got a fair game + + align:start position:0% +unbiased random walk you got a fair game + + + align:start position:0% +unbiased random walk you got a fair game +and so it says right away well maybe the + + align:start position:0% +and so it says right away well maybe the + + + align:start position:0% +and so it says right away well maybe the +result is going to be different for a + + align:start position:0% +result is going to be different for a + + + align:start position:0% +result is going to be different for a +fair game than the game we're playing in + + align:start position:0% +fair game than the game we're playing in + + + align:start position:0% +fair game than the game we're playing in +the casino where it's where it's + + align:start position:0% +the casino where it's where it's + + + align:start position:0% +the casino where it's where it's +biased okay so let's look at the casino + + align:start position:0% +biased okay so let's look at the casino + + + align:start position:0% +biased okay so let's look at the casino +game where p is not a half then the + + align:start position:0% +game where p is not a half then the + + + align:start position:0% +game where p is not a half then the +roots are + + align:start position:0% +roots are + + + align:start position:0% +roots are +different later we'll go back and + + align:start position:0% +different later we'll go back and + + + align:start position:0% +different later we'll go back and +analyze the case when the roots are the + + align:start position:0% +analyze the case when the roots are the + + + align:start position:0% +analyze the case when the roots are the +same for the fair + + align:start position:0% + + + + align:start position:0% + +game all right so if p is not a + + align:start position:0% + + + + align:start position:0% + +half then we can solve for + + align:start position:0% +half then we can solve for + + + align:start position:0% +half then we can solve for +xn xn is some + + align:start position:0% +xn xn is some + + + align:start position:0% +xn xn is some +constant times the first root to the N + + align:start position:0% +constant times the first root to the N + + + align:start position:0% +constant times the first root to the N +power plus a constant times the second + + align:start position:0% +power plus a constant times the second + + + align:start position:0% +power plus a constant times the second +root to the nth power remember that's + + align:start position:0% +root to the nth power remember that's + + + align:start position:0% +root to the nth power remember that's +how it works for any linear homogeneous + + align:start position:0% + + + + align:start position:0% + +recurrence okay and that's + + align:start position:0% +recurrence okay and that's + + + align:start position:0% +recurrence okay and that's +easy because the second root was one + + align:start position:0% +easy because the second root was one + + + align:start position:0% +easy because the second root was one +this is just plus b one to the N is is + + align:start position:0% +this is just plus b one to the N is is + + + align:start position:0% +this is just plus b one to the N is is +one + + align:start position:0% +one + + + align:start position:0% +one +how do I figure out what A and B + + align:start position:0% +how do I figure out what A and B + + + align:start position:0% +how do I figure out what A and B +are boundary conditions very good okay + + align:start position:0% +are boundary conditions very good okay + + + align:start position:0% +are boundary conditions very good okay +so let's look at the boundary + + align:start position:0% + + + + align:start position:0% + +conditions + + align:start position:0% + + + + align:start position:0% + +okay so the first boundary condition is + + align:start position:0% +okay so the first boundary condition is + + + align:start position:0% +okay so the first boundary condition is +at + + align:start position:0% +at + + + align:start position:0% +at +zero so we have 0 equals + + align:start position:0% +zero so we have 0 equals + + + align:start position:0% +zero so we have 0 equals +x0 plugging in there oops I forgot the N + + align:start position:0% +x0 plugging in there oops I forgot the N + + + align:start position:0% +x0 plugging in there oops I forgot the N +up + + align:start position:0% +up + + + align:start position:0% +up +here plugging in n equals z well this to + + align:start position:0% +here plugging in n equals z well this to + + + align:start position:0% +here plugging in n equals z well this to +the zero is just one that is a plus + + align:start position:0% +the zero is just one that is a plus + + + align:start position:0% +the zero is just one that is a plus +b that means that b equals minus + + align:start position:0% +b that means that b equals minus + + + align:start position:0% +b that means that b equals minus +a then the second boundary condition is + + align:start position:0% +a then the second boundary condition is + + + align:start position:0% +a then the second boundary condition is +1 = X + + align:start position:0% +1 = X + + + align:start position:0% +1 = X +subt and that is a 1 - p over P to the + + align:start position:0% +subt and that is a 1 - p over P to the + + + align:start position:0% +subt and that is a 1 - p over P to the +t plus b but B was minus + + align:start position:0% + + + + align:start position:0% + +a and now I can solve for a all right so + + align:start position:0% +a and now I can solve for a all right so + + + align:start position:0% +a and now I can solve for a all right so +that means + + align:start position:0% +that means + + + align:start position:0% +that means +that + + align:start position:0% +that + + + align:start position:0% +that +a equal 1 + + align:start position:0% +a equal 1 + + + align:start position:0% +a equal 1 +over 1 - p + + align:start position:0% +over 1 - p + + + align:start position:0% +over 1 - p +P the T + + align:start position:0% +P the T + + + align:start position:0% +P the T +-1 and B isga A -1 over 1 - p p the T + + align:start position:0% +-1 and B isga A -1 over 1 - p p the T + + + align:start position:0% +-1 and B isga A -1 over 1 - p p the T +minus + + align:start position:0% +minus + + + align:start position:0% +minus +one all right then I plug those back in + + align:start position:0% +one all right then I plug those back in + + + align:start position:0% +one all right then I plug those back in +to the formula for + + align:start position:0% +to the formula for + + + align:start position:0% +to the formula for +xn all right so I take here's my + + align:start position:0% +xn all right so I take here's my + + + align:start position:0% +xn all right so I take here's my +constant a I multiply that times 1 - p + + align:start position:0% +constant a I multiply that times 1 - p + + + align:start position:0% +constant a I multiply that times 1 - p +over P to the N plus I add this in + + align:start position:0% +over P to the N plus I add this in + + + align:start position:0% +over P to the N plus I add this in +all right so this means that the + + align:start position:0% +all right so this means that the + + + align:start position:0% +all right so this means that the +probability of going home a + + align:start position:0% +probability of going home a + + + align:start position:0% +probability of going home a +winner is 1 minus p over P to the + + align:start position:0% +winner is 1 minus p over P to the + + + align:start position:0% +winner is 1 minus p over P to the +N over that thing 1 - p over P to the T + + align:start position:0% +N over that thing 1 - p over P to the T + + + align:start position:0% +N over that thing 1 - p over P to the T +minus 1 plus the B term which really is + + align:start position:0% +minus 1 plus the B term which really is + + + align:start position:0% +minus 1 plus the B term which really is +a minus term here is well it's just + + align:start position:0% +a minus term here is well it's just + + + align:start position:0% +a minus term here is well it's just +minus + + align:start position:0% +minus + + + align:start position:0% +minus +one put that on top here + + align:start position:0% +one put that on top here + + + align:start position:0% +one put that on top here +okay now that sort of looks messy + + align:start position:0% +okay now that sort of looks messy + + + align:start position:0% +okay now that sort of looks messy +um but there's a simplification to get + + align:start position:0% +um but there's a simplification to get + + + align:start position:0% +um but there's a simplification to get +an upper bound that's very + + align:start position:0% +an upper bound that's very + + + align:start position:0% +an upper bound that's very +close in particular if you have an bias + + align:start position:0% +close in particular if you have an bias + + + align:start position:0% +close in particular if you have an bias +game against you so if p is less than a + + align:start position:0% +game against you so if p is less than a + + + align:start position:0% +game against you so if p is less than a +half as it is in + + align:start position:0% +half as it is in + + + align:start position:0% +half as it is in +roulette then this is a number bigger + + align:start position:0% +roulette then this is a number bigger + + + align:start position:0% +roulette then this is a number bigger +than + + align:start position:0% +than + + + align:start position:0% +than +one that means that 1 minus p over p is + + align:start position:0% +one that means that 1 minus p over p is + + + align:start position:0% +one that means that 1 minus p over p is +bigger than + + align:start position:0% + + + + align:start position:0% + +one so this is bigger than one this is + + align:start position:0% +one so this is bigger than one this is + + + align:start position:0% +one so this is bigger than one this is +bigger than one t is the upper limit + + align:start position:0% +bigger than one t is the upper limit + + + align:start position:0% +bigger than one t is the upper limit +it's n plus M so I've got a bigger + + align:start position:0% +it's n plus M so I've got a bigger + + + align:start position:0% +it's n plus M so I've got a bigger +number down here than I do here so I got + + align:start position:0% +number down here than I do here so I got + + + align:start position:0% +number down here than I do here so I got +an overall it's a fraction less than one + + align:start position:0% +an overall it's a fraction less than one + + + align:start position:0% +an overall it's a fraction less than one +and when you have a fraction less than + + align:start position:0% +and when you have a fraction less than + + + align:start position:0% +and when you have a fraction less than +one if you add one to the numerator and + + align:start position:0% +one if you add one to the numerator and + + + align:start position:0% +one if you add one to the numerator and +the denominator it gets closer to one + + align:start position:0% +the denominator it gets closer to one + + + align:start position:0% +the denominator it gets closer to one +gets + + align:start position:0% +gets + + + align:start position:0% +gets +bigger all right so this is upper + + align:start position:0% +bigger all right so this is upper + + + align:start position:0% +bigger all right so this is upper +bounded by just adding one to each of + + align:start position:0% +bounded by just adding one to each of + + + align:start position:0% +bounded by just adding one to each of +these it's upper bounded by this over + + align:start position:0% +these it's upper bounded by this over + + + align:start position:0% +these it's upper bounded by this over +that which is 1us p/ P to the N minus + + align:start position:0% +that which is 1us p/ P to the N minus + + + align:start position:0% +that which is 1us p/ P to the N minus +t and t is just n plus M so this + + align:start position:0% +t and t is just n plus M so this + + + align:start position:0% +t and t is just n plus M so this +equals well why don't I turn it upside + + align:start position:0% +equals well why don't I turn it upside + + + align:start position:0% +equals well why don't I turn it upside +down make it P over 1 minus P to get a + + align:start position:0% +down make it P over 1 minus P to get a + + + align:start position:0% +down make it P over 1 minus P to get a +fraction it's less than one T minus n + + align:start position:0% +fraction it's less than one T minus n + + + align:start position:0% +fraction it's less than one T minus n +and that equals p over 1 minus P to the + + align:start position:0% + + + + align:start position:0% + +m and this is how much you're trying to + + align:start position:0% +m and this is how much you're trying to + + + align:start position:0% +m and this is how much you're trying to +get ahead $100 in the case of my + + align:start position:0% +get ahead $100 in the case of my + + + align:start position:0% +get ahead $100 in the case of my +mother-in-law + + align:start position:0% +mother-in-law + + + align:start position:0% +mother-in-law +say okay so what we've proved let me + + align:start position:0% +say okay so what we've proved let me + + + align:start position:0% +say okay so what we've proved let me +State what we've proved is a + + align:start position:0% + + + + align:start position:0% + +theorem so we prove + + align:start position:0% +theorem so we prove + + + align:start position:0% +theorem so we prove +that + + align:start position:0% + + + + align:start position:0% + +if p is less than a half if you're + + align:start position:0% +if p is less than a half if you're + + + align:start position:0% +if p is less than a half if you're +likely to more likely to lose a bet than + + align:start position:0% +likely to more likely to lose a bet than + + + align:start position:0% +likely to more likely to lose a bet than +win + + align:start position:0% +win + + + align:start position:0% +win +it then the + + align:start position:0% +it then the + + + align:start position:0% +it then the +probability that you win + + align:start position:0% +probability that you win + + + align:start position:0% +probability that you win +MLL before you lose + + align:start position:0% +MLL before you lose + + + align:start position:0% +MLL before you lose +n + + align:start position:0% +n + + + align:start position:0% +n +dollars is at most p over 1 minus P to + + align:start position:0% +dollars is at most p over 1 minus P to + + + align:start position:0% +dollars is at most p over 1 minus P to +the + + align:start position:0% +the + + + align:start position:0% +the +m that's what we just + + align:start position:0% +m that's what we just + + + align:start position:0% +m that's what we just +proved + + align:start position:0% +proved + + + align:start position:0% +proved +and so now you can plug in values for + + align:start position:0% +and so now you can plug in values for + + + align:start position:0% +and so now you can plug in values for +example for + + align:start position:0% + + + + align:start position:0% + +roulette P equal + + align:start position:0% +roulette P equal + + + align:start position:0% +roulette P equal +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +9/19 which means that P over 1 minus + + align:start position:0% +9/19 which means that P over 1 minus + + + align:start position:0% +9/19 which means that P over 1 minus +P well that's going to be + + align:start position:0% +P well that's going to be + + + align:start position:0% +P well that's going to be +9/9 over + + align:start position:0% +9/9 over + + + align:start position:0% +9/9 over +109 which is just + + align:start position:0% + + + + align:start position:0% + +9/10 all right and if M the amount you + + align:start position:0% +9/10 all right and if M the amount you + + + align:start position:0% +9/10 all right and if M the amount you +want to win is $100 + + align:start position:0% + + + + align:start position:0% + +and N is $1,000 that's what you start + + align:start position:0% +and N is $1,000 that's what you start + + + align:start position:0% +and N is $1,000 that's what you start +with and are you're willing to + + align:start position:0% +with and are you're willing to + + + align:start position:0% +with and are you're willing to +lose well the probability you win you go + + align:start position:0% +lose well the probability you win you go + + + align:start position:0% +lose well the probability you win you go +home + + align:start position:0% + + + + align:start position:0% + +happy that you w star or that you win + + align:start position:0% + + + + align:start position:0% + +$100 is less than or equal to + + align:start position:0% +$100 is less than or equal to + + + align:start position:0% +$100 is less than or equal to +9/10 raised to the m which is + + align:start position:0% +9/10 raised to the m which is + + + align:start position:0% +9/10 raised to the m which is +100 so it's 9/10 to the 100 and that + + align:start position:0% +100 so it's 9/10 to the 100 and that + + + align:start position:0% +100 so it's 9/10 to the 100 and that +turns out to be less than one and 3 + + align:start position:0% + + + + align:start position:0% + +7,648 which is where that answer came + + align:start position:0% +7,648 which is where that answer came + + + align:start position:0% +7,648 which is where that answer came +from now you can see why my + + align:start position:0% +from now you can see why my + + + align:start position:0% +from now you can see why my +mother-in-law may have gotten lost + + align:start position:0% +mother-in-law may have gotten lost + + + align:start position:0% +mother-in-law may have gotten lost +somewhere here you know in the + + align:start position:0% +somewhere here you know in the + + + align:start position:0% +somewhere here you know in the +calculations but this is a proof that + + align:start position:0% +calculations but this is a proof that + + + align:start position:0% +calculations but this is a proof that +the chance you win a 100 bucks before + + align:start position:0% +the chance you win a 100 bucks before + + + align:start position:0% +the chance you win a 100 bucks before +you lose a th000 bucks is is very very + + align:start position:0% +you lose a th000 bucks is is very very + + + align:start position:0% +you lose a th000 bucks is is very very +small now do you see why the answer is + + align:start position:0% +small now do you see why the answer is + + + align:start position:0% +small now do you see why the answer is +no better than if you came with a + + align:start position:0% +no better than if you came with a + + + align:start position:0% +no better than if you came with a +million dollars in your + + align:start position:0% +million dollars in your + + + align:start position:0% +million dollars in your +pocket say you came with n equals a + + align:start position:0% +pocket say you came with n equals a + + + align:start position:0% +pocket say you came with n equals a +million + + align:start position:0% +million + + + align:start position:0% +million +dollars why is the answer not + + align:start position:0% + + + + align:start position:0% + +changing yeah + + align:start position:0% + + + + align:start position:0% + +yeah you're already in a really deep + + align:start position:0% +yeah you're already in a really deep + + + align:start position:0% +yeah you're already in a really deep +hole Ah that's the intuition that's + + align:start position:0% +hole Ah that's the intuition that's + + + align:start position:0% +hole Ah that's the intuition that's +right and we're going to get to that in + + align:start position:0% +right and we're going to get to that in + + + align:start position:0% +right and we're going to get to that in +a minute I want to know from the + + align:start position:0% +a minute I want to know from the + + + align:start position:0% +a minute I want to know from the +formula why is it no difference if I + + align:start position:0% +formula why is it no difference if I + + + align:start position:0% +formula why is it no difference if I +come with thousand versus a million + + align:start position:0% +come with thousand versus a million + + + align:start position:0% +come with thousand versus a million +dollars + + align:start position:0% +dollars + + + align:start position:0% +dollars +yeah yeah the formula has nothing to do + + align:start position:0% +yeah yeah the formula has nothing to do + + + align:start position:0% +yeah yeah the formula has nothing to do +with end you could come with A1 trillion + + align:start position:0% +with end you could come with A1 trillion + + + align:start position:0% +with end you could come with A1 trillion +dollar in your + + align:start position:0% +dollar in your + + + align:start position:0% +dollar in your +wallet and it doesn't improve this bound + + align:start position:0% +wallet and it doesn't improve this bound + + + align:start position:0% +wallet and it doesn't improve this bound +this bound only depends on what you're + + align:start position:0% +this bound only depends on what you're + + + align:start position:0% +this bound only depends on what you're +trying to win not on how much you came + + align:start position:0% +trying to win not on how much you came + + + align:start position:0% +trying to win not on how much you came +with so no matter how much you come with + + align:start position:0% +with so no matter how much you come with + + + align:start position:0% +with so no matter how much you come with +the chance you win a 100 bucks before + + align:start position:0% +the chance you win a 100 bucks before + + + align:start position:0% +the chance you win a 100 bucks before +you lose everything is at most + + align:start position:0% + + + + align:start position:0% + +137,000 now we can plug in some other + + align:start position:0% +137,000 now we can plug in some other + + + align:start position:0% +137,000 now we can plug in some other +values just for + + align:start position:0% +values just for + + + align:start position:0% +values just for +fun you know different values of M + + align:start position:0% + + + + align:start position:0% + +you know if you thought 1 and 37,000 was + + align:start position:0% +you know if you thought 1 and 37,000 was + + + align:start position:0% +you know if you thought 1 and 37,000 was +unlikely the chance of winning + + align:start position:0% + + + + align:start position:0% + +$1,000 or a th000 bets + + align:start position:0% +$1,000 or a th000 bets + + + align:start position:0% +$1,000 or a th000 bets +worth before you're broke well that's + + align:start position:0% +worth before you're broke well that's + + + align:start position:0% +worth before you're broke well that's +less than + + align:start position:0% +less than + + + align:start position:0% +less than +9/10 to the + + align:start position:0% +9/10 to the + + + align:start position:0% +9/10 to the +Thousand that's less + + align:start position:0% +Thousand that's less + + + align:start position:0% +Thousand that's less +than 2 * 10- + + align:start position:0% +than 2 * 10- + + + align:start position:0% +than 2 * 10- +46 really really really unlikely even + + align:start position:0% +46 really really really unlikely even + + + align:start position:0% +46 really really really unlikely even +winning + + align:start position:0% + + + + align:start position:0% + +$10 is not + + align:start position:0% +$10 is not + + + align:start position:0% +$10 is not +likely this just plug in the numbers + + align:start position:0% +likely this just plug in the numbers + + + align:start position:0% +likely this just plug in the numbers +probability you win $10 betting a dollar + + align:start position:0% +probability you win $10 betting a dollar + + + align:start position:0% +probability you win $10 betting a dollar +at a + + align:start position:0% +at a + + + align:start position:0% +at a +time is less than 9/10 to the 10th + + align:start position:0% +time is less than 9/10 to the 10th + + + align:start position:0% +time is less than 9/10 to the 10th +power that's less than + + align:start position:0% + + + + align:start position:0% + +35 you can come to the casino with $10 + + align:start position:0% +35 you can come to the casino with $10 + + + align:start position:0% +35 you can come to the casino with $10 +million bet a dollar at a + + align:start position:0% +million bet a dollar at a + + + align:start position:0% +million bet a dollar at a +time and you quit if you just get up 10 + + align:start position:0% +time and you quit if you just get up 10 + + + align:start position:0% +time and you quit if you just get up 10 +bets get up $10 the chance you get up + + align:start position:0% +bets get up $10 the chance you get up + + + align:start position:0% +bets get up $10 the chance you get up +$10 before you lose 10 million how about + + align:start position:0% +$10 before you lose 10 million how about + + + align:start position:0% +$10 before you lose 10 million how about +one and three you're twice as likely to + + align:start position:0% +one and three you're twice as likely to + + + align:start position:0% +one and three you're twice as likely to +lose $10 million as you are to win 10 + + align:start position:0% +lose $10 million as you are to win 10 + + + align:start position:0% +lose $10 million as you are to win 10 +that just weird right because it's + + align:start position:0% +that just weird right because it's + + + align:start position:0% +that just weird right because it's +almost a fair game it's almost 50/50 any + + align:start position:0% +almost a fair game it's almost 50/50 any + + + align:start position:0% +almost a fair game it's almost 50/50 any +questions about the + + align:start position:0% + + + + align:start position:0% + +analysis that's I don't I find that + + align:start position:0% +analysis that's I don't I find that + + + align:start position:0% +analysis that's I don't I find that +shocking right you know just the + + align:start position:0% +shocking right you know just the + + + align:start position:0% +shocking right you know just the +intuition would seem to say otherwise so + + align:start position:0% +intuition would seem to say otherwise so + + + align:start position:0% +intuition would seem to say otherwise so +I guess there's a moral here if you're + + align:start position:0% +I guess there's a moral here if you're + + + align:start position:0% +I guess there's a moral here if you're +going to gamble learn how to count cards + + align:start position:0% +going to gamble learn how to count cards + + + align:start position:0% +going to gamble learn how to count cards +in blackjack or some game where you can + + align:start position:0% +in blackjack or some game where you can + + + align:start position:0% +in blackjack or some game where you can +make it even because even in a game + + align:start position:0% +make it even because even in a game + + + align:start position:0% +make it even because even in a game +where it's pretty close you're doomed + + align:start position:0% +where it's pretty close you're doomed + + + align:start position:0% +where it's pretty close you're doomed +you know you're just never going to go + + align:start position:0% +you know you're just never going to go + + + align:start position:0% +you know you're just never going to go +home + + align:start position:0% +home + + + align:start position:0% +home +happy all right now if you can have a + + align:start position:0% +happy all right now if you can have a + + + align:start position:0% +happy all right now if you can have a +fair game the world changes much better + + align:start position:0% +fair game the world changes much better + + + align:start position:0% +fair game the world changes much better +circumstance so actually let's do this + + align:start position:0% +circumstance so actually let's do this + + + align:start position:0% +circumstance so actually let's do this +same analysis for a fair game because + + align:start position:0% +same analysis for a fair game because + + + align:start position:0% +same analysis for a fair game because +that's where our intuition really comes + + align:start position:0% +that's where our intuition really comes + + + align:start position:0% +that's where our intuition really comes +from because we're thinking of this game + + align:start position:0% +from because we're thinking of this game + + + align:start position:0% +from because we're thinking of this game +as almost fair and in a fair game the + + align:start position:0% +as almost fair and in a fair game the + + + align:start position:0% +as almost fair and in a fair game the +answer is going to be very different and + + align:start position:0% +answer is going to be very different and + + + align:start position:0% +answer is going to be very different and +it all goes back to the recurrence and + + align:start position:0% +it all goes back to the recurrence and + + + align:start position:0% +it all goes back to the recurrence and +the roots of the characteristic equation + + align:start position:0% +the roots of the characteristic equation + + + align:start position:0% +the roots of the characteristic equation +because in a fair + + align:start position:0% + + + + align:start position:0% + +game p is a + + align:start position:0% + + + + align:start position:0% + +half and then you have a double root 1 - + + align:start position:0% +half and then you have a double root 1 - + + + align:start position:0% +half and then you have a double root 1 - +a half over half equals 1 and that means + + align:start position:0% +a half over half equals 1 and that means + + + align:start position:0% +a half over half equals 1 and that means +a double + + align:start position:0% + + + + align:start position:0% + +root at + + align:start position:0% +root at + + + align:start position:0% +root at +one and that changes everything so let's + + align:start position:0% +one and that changes everything so let's + + + align:start position:0% +one and that changes everything so let's +let's go through now and do all this + + align:start position:0% +let's go through now and do all this + + + align:start position:0% +let's go through now and do all this +analysis uh in the case of a fair + + align:start position:0% +analysis uh in the case of a fair + + + align:start position:0% +analysis uh in the case of a fair +game and this will give us practice with + + align:start position:0% +game and this will give us practice with + + + align:start position:0% +game and this will give us practice with +double roots and recurrences because as + + align:start position:0% +double roots and recurrences because as + + + align:start position:0% +double roots and recurrences because as +you see now it does + + align:start position:0% +you see now it does + + + align:start position:0% +you see now it does +happen + + align:start position:0% + + + + align:start position:0% + +let's figure out the chance that we go + + align:start position:0% +let's figure out the chance that we go + + + align:start position:0% +let's figure out the chance that we go +home a + + align:start position:0% + + + + align:start position:0% + +winner okay so let's see in this case we + + align:start position:0% +winner okay so let's see in this case we + + + align:start position:0% +winner okay so let's see in this case we +know the + + align:start position:0% +know the + + + align:start position:0% +know the +roots can anybody tell me what formula + + align:start position:0% +roots can anybody tell me what formula + + + align:start position:0% +roots can anybody tell me what formula +we're going to use for the + + align:start position:0% +we're going to use for the + + + align:start position:0% +we're going to use for the +solution got a double root at one so + + align:start position:0% +solution got a double root at one so + + + align:start position:0% +solution got a double root at one so +there's going to be a one to the end + + align:start position:0% +there's going to be a one to the end + + + align:start position:0% +there's going to be a one to the end +here I don't just put a constant a in + + align:start position:0% +here I don't just put a constant a in + + + align:start position:0% +here I don't just put a constant a in +front what do I do with a double + + align:start position:0% +front what do I do with a double + + + align:start position:0% +front what do I do with a double +root what is it n a n not quite a n you + + align:start position:0% +root what is it n a n not quite a n you + + + align:start position:0% +root what is it n a n not quite a n you +got an A N + + align:start position:0% +got an A N + + + align:start position:0% +got an A N +here plus b that's what you do for a + + align:start position:0% +here plus b that's what you do for a + + + align:start position:0% +here plus b that's what you do for a +double root because you you make a + + align:start position:0% +double root because you you make a + + + align:start position:0% +double root because you you make a +first-degree polinomial in N here so we + + align:start position:0% +first-degree polinomial in N here so we + + + align:start position:0% +first-degree polinomial in N here so we +plug that in the roots at one so it's + + align:start position:0% +plug that in the roots at one so it's + + + align:start position:0% +plug that in the roots at one so it's +really easy the solution is really easy + + align:start position:0% +really easy the solution is really easy + + + align:start position:0% +really easy the solution is really easy +now no messy powers or anything it's + + align:start position:0% +now no messy powers or anything it's + + + align:start position:0% +now no messy powers or anything it's +just a n plus + + align:start position:0% +just a n plus + + + align:start position:0% +just a n plus +b and I can figure out a and B from the + + align:start position:0% +b and I can figure out a and B from the + + + align:start position:0% +b and I can figure out a and B from the +boundary + + align:start position:0% + + + + align:start position:0% + +conditions all right x0 is + + align:start position:0% +conditions all right x0 is + + + align:start position:0% +conditions all right x0 is +zero x0 is just + + align:start position:0% +zero x0 is just + + + align:start position:0% +zero x0 is just +B because it's a * Z goes away and that + + align:start position:0% +B because it's a * Z goes away and that + + + align:start position:0% +B because it's a * Z goes away and that +means the b equals zero this is getting + + align:start position:0% +means the b equals zero this is getting + + + align:start position:0% +means the b equals zero this is getting +really + + align:start position:0% +really + + + align:start position:0% +really +simple one is + + align:start position:0% +simple one is + + + align:start position:0% +simple one is +XT and that's a plus b but B was zero + + align:start position:0% +XT and that's a plus b but B was zero + + + align:start position:0% +XT and that's a plus b but B was zero +that's a 1 a * 1 + B that's just + + align:start position:0% +that's a 1 a * 1 + B that's just + + + align:start position:0% +that's a 1 a * 1 + B that's just +a it means + + align:start position:0% + + + + align:start position:0% + +aals oh I didn't do that oh a n good n's + + align:start position:0% +aals oh I didn't do that oh a n good n's + + + align:start position:0% +aals oh I didn't do that oh a n good n's +not one n's T so it's a t plus b this is + + align:start position:0% +not one n's T so it's a t plus b this is + + + align:start position:0% +not one n's T so it's a t plus b this is +a t here so a t equals 1 that means a is + + align:start position:0% +a t here so a t equals 1 that means a is + + + align:start position:0% +a t here so a t equals 1 that means a is +1 over + + align:start position:0% + + + + align:start position:0% + +T all right that means + + align:start position:0% +T all right that means + + + align:start position:0% +T all right that means +that X + + align:start position:0% +that X + + + align:start position:0% +that X +n is n / T and T is the total the top + + align:start position:0% +n is n / T and T is the total the top + + + align:start position:0% +n is n / T and T is the total the top +limit is n plus M because you quit if + + align:start position:0% +limit is n plus M because you quit if + + + align:start position:0% +limit is n plus M because you quit if +you get ahead M dollars this is just now + + align:start position:0% +you get ahead M dollars this is just now + + + align:start position:0% +you get ahead M dollars this is just now +n over n + + + align:start position:0% +n over n + + + + align:start position:0% +n over n + +m all right + + align:start position:0% +m all right + + + align:start position:0% +m all right +so let's write that down it's a + + align:start position:0% + + + + align:start position:0% + +theorem if p is a half right you have a + + align:start position:0% +theorem if p is a half right you have a + + + align:start position:0% +theorem if p is a half right you have a +fair game + + align:start position:0% +fair game + + + align:start position:0% +fair game +then the + + align:start position:0% +then the + + + align:start position:0% +then the +probability you win + + align:start position:0% +probability you win + + + align:start position:0% +probability you win +M before you + + align:start position:0% +M before you + + + align:start position:0% +M before you +lose + + align:start position:0% +lose + + + align:start position:0% +lose +n is just n Over N plus + + align:start position:0% +n is just n Over N plus + + + align:start position:0% +n is just n Over N plus +M and this might fit the intuition + + align:start position:0% +M and this might fit the intuition + + + align:start position:0% +M and this might fit the intuition +better all right so for the + + align:start position:0% +better all right so for the + + + align:start position:0% +better all right so for the +Mother-in-law + + align:start position:0% + + + + align:start position:0% + +strategy if m is 100 + + align:start position:0% +strategy if m is 100 + + + align:start position:0% +strategy if m is 100 +and N is a + + align:start position:0% + + + + align:start position:0% + +th what's the probability you win you go + + align:start position:0% +th what's the probability you win you go + + + align:start position:0% +th what's the probability you win you go +home a + + align:start position:0% + + + + align:start position:0% + +winner + + align:start position:0% +winner + + + align:start position:0% +winner +yeah, over a + + align:start position:0% +yeah, over a + + + align:start position:0% +yeah, over a +th000 plus + + align:start position:0% +th000 plus + + + align:start position:0% +th000 plus +100,000 over 1100 is 10 over + + align:start position:0% +100,000 over 1100 is 10 over + + + align:start position:0% +100,000 over 1100 is 10 over +11 so she does go home happy most of the + + align:start position:0% +11 so she does go home happy most of the + + + align:start position:0% +11 so she does go home happy most of the +time 10 out of 11 Knights if she's + + align:start position:0% +time 10 out of 11 Knights if she's + + + align:start position:0% +time 10 out of 11 Knights if she's +playing a fair + + align:start position:0% +playing a fair + + + align:start position:0% +playing a fair +game all right any + + align:start position:0% +game all right any + + + align:start position:0% +game all right any +questions about that so the trouble we + + align:start position:0% +questions about that so the trouble we + + + align:start position:0% +questions about that so the trouble we +get into + + align:start position:0% +get into + + + align:start position:0% +get into +here is + + align:start position:0% +here is + + + align:start position:0% +here is +that the fair game results match our + + align:start position:0% +that the fair game results match our + + + align:start position:0% +that the fair game results match our +intuition you know if you're 10 times as + + align:start position:0% +intuition you know if you're 10 times as + + + align:start position:0% +intuition you know if you're 10 times as +likely you have 10 times as much money + + align:start position:0% +likely you have 10 times as much money + + + align:start position:0% +likely you have 10 times as much money +in a fair game you'd expect to go home + + align:start position:0% +in a fair game you'd expect to go home + + + align:start position:0% +in a fair game you'd expect to go home +Happy 10 out of 11 nights that makes a + + align:start position:0% +Happy 10 out of 11 nights that makes a + + + align:start position:0% +Happy 10 out of 11 nights that makes a +lot of sense you you go home Happy 10 + + align:start position:0% +lot of sense you you go home Happy 10 + + + align:start position:0% +lot of sense you you go home Happy 10 +and then you lose + + align:start position:0% +and then you lose + + + align:start position:0% +and then you lose +the 11th that's a 10:1 ratio which is + + align:start position:0% +the 11th that's a 10:1 ratio which is + + + align:start position:0% +the 11th that's a 10:1 ratio which is +the money brought into the + + align:start position:0% +the money brought into the + + + align:start position:0% +the money brought into the +game the trouble we get into is the fair + + align:start position:0% +game the trouble we get into is the fair + + + align:start position:0% +game the trouble we get into is the fair +game is very close to the real game + + align:start position:0% +game is very close to the real game + + + align:start position:0% +game is very close to the real game +instead of 5050 it's + + align:start position:0% +instead of 5050 it's + + + align:start position:0% +instead of 5050 it's +4753 and so our intuition says the + + align:start position:0% +4753 and so our intuition says the + + + align:start position:0% +4753 and so our intuition says the +results the probability of going home + + align:start position:0% +results the probability of going home + + + align:start position:0% +results the probability of going home +happy in the fair game should be close + + align:start position:0% +happy in the fair game should be close + + + align:start position:0% +happy in the fair game should be close +to the probability of going home happy + + align:start position:0% +to the probability of going home happy + + + align:start position:0% +to the probability of going home happy +in the real game and that's not true + + align:start position:0% +in the real game and that's not true + + + align:start position:0% +in the real game and that's not true +there's a discontinuity here because of + + align:start position:0% +there's a discontinuity here because of + + + align:start position:0% +there's a discontinuity here because of +the double rout and the character + + align:start position:0% +the double rout and the character + + + align:start position:0% +the double rout and the character +completely changes so instead of being + + align:start position:0% +completely changes so instead of being + + + align:start position:0% +completely changes so instead of being +close to 10 out of 11 you're down there + + align:start position:0% +close to 10 out of 11 you're down there + + + align:start position:0% +close to 10 out of 11 you're down there +at + + align:start position:0% +at + + + align:start position:0% +at +137,000 completely different + + align:start position:0% +137,000 completely different + + + align:start position:0% +137,000 completely different +Behavior + + align:start position:0% +Behavior + + + align:start position:0% +Behavior +okay any + + align:start position:0% +okay any + + + align:start position:0% +okay any +questions all right so let me give you + + align:start position:0% +questions all right so let me give you + + + align:start position:0% +questions all right so let me give you +an + + align:start position:0% +an + + + align:start position:0% +an +idea like one and then you kind of do + + align:start position:0% +idea like one and then you kind of do + + + align:start position:0% +idea like one and then you kind of do +that repeatedly ah now if I did m equal + + align:start position:0% +that repeatedly ah now if I did m equal + + + align:start position:0% +that repeatedly ah now if I did m equal +1 I could use that as enough for bound + + align:start position:0% +1 I could use that as enough for bound + + + align:start position:0% +1 I could use that as enough for bound +and it's not so interesting but say 90% + + align:start position:0% +and it's not so interesting but say 90% + + + align:start position:0% +and it's not so interesting but say 90% +um but I would actually go plug it back + + align:start position:0% +um but I would actually go plug it back + + + align:start position:0% +um but I would actually go plug it back +in here so this would be n plus one and + + align:start position:0% +in here so this would be n plus one and + + + align:start position:0% +in here so this would be n plus one and +it would depend how much money I brought + + align:start position:0% +it would depend how much money I brought + + + align:start position:0% +it would depend how much money I brought +but there is a pretty good chance I go + + align:start position:0% +but there is a pretty good chance I go + + + align:start position:0% +but there is a pretty good chance I go +home a winner for n equals one oh sorry + + align:start position:0% +home a winner for n equals one oh sorry + + + align:start position:0% +home a winner for n equals one oh sorry +m equals one right because I got a + + align:start position:0% +m equals one right because I got a + + + align:start position:0% +m equals one right because I got a +pretty good chance that I either 47% + + align:start position:0% +pretty good chance that I either 47% + + + align:start position:0% +pretty good chance that I either 47% +chance I win the first time then I go + + align:start position:0% +chance I win the first time then I go + + + align:start position:0% +chance I win the first time then I go +home happy if I lost the first time now + + align:start position:0% +home happy if I lost the first time now + + + align:start position:0% +home happy if I lost the first time now +I just got to win twice and I might win + + align:start position:0% +I just got to win twice and I might win + + + align:start position:0% +I just got to win twice and I might win +twice in a row that'll happen about 20% + + align:start position:0% +twice in a row that'll happen about 20% + + + align:start position:0% +twice in a row that'll happen about 20% +of the time if I lose that I I got to + + align:start position:0% +of the time if I lose that I I got to + + + align:start position:0% +of the time if I lose that I I got to +win three in a row that'll happen around + + align:start position:0% +win three in a row that'll happen around + + + align:start position:0% +win three in a row that'll happen around +10% of the time so I got 10 plus 20 plus + + align:start position:0% +10% of the time so I got 10 plus 20 plus + + + align:start position:0% +10% of the time so I got 10 plus 20 plus +almost 50 most of the time I'm going to + + align:start position:0% +almost 50 most of the time I'm going to + + + align:start position:0% +almost 50 most of the time I'm going to +go home happy if I just have to get + + align:start position:0% +go home happy if I just have to get + + + align:start position:0% +go home happy if I just have to get +ahead by + + align:start position:0% +ahead by + + + align:start position:0% +ahead by +one but it doesn't take much more than + + align:start position:0% +one but it doesn't take much more than + + + align:start position:0% +one but it doesn't take much more than +one before you're not likely to go home + + align:start position:0% +one before you're not likely to go home + + + align:start position:0% +one before you're not likely to go home +Happy getting a head 10 is not going to + + align:start position:0% +Happy getting a head 10 is not going to + + + align:start position:0% +Happy getting a head 10 is not going to +happen very likely now you want to + + align:start position:0% +happen very likely now you want to + + + align:start position:0% +happen very likely now you want to +recurse on + + align:start position:0% +recurse on + + + align:start position:0% +recurse on +that you know I'm pretty likely to get + + align:start position:0% +that you know I'm pretty likely to get + + + align:start position:0% +that you know I'm pretty likely to get +head by + + align:start position:0% +head by + + + align:start position:0% +head by +one well okay get ahead by one now I'm + + align:start position:0% +one well okay get ahead by one now I'm + + + align:start position:0% +one well okay get ahead by one now I'm +pretty likely to do it again all right I + + align:start position:0% +pretty likely to do it again all right I + + + align:start position:0% +pretty likely to do it again all right I +did it again now I'm pretty likely to do + + align:start position:0% +did it again now I'm pretty likely to do + + + align:start position:0% +did it again now I'm pretty likely to do +it again and there's this thing called + + align:start position:0% +it again and there's this thing called + + + align:start position:0% +it again and there's this thing called +induction that we worried a lot about so + + align:start position:0% +induction that we worried a lot about so + + + align:start position:0% +induction that we worried a lot about so +by induction we're likely to go home + + align:start position:0% +by induction we're likely to go home + + + align:start position:0% +by induction we're likely to go home +happy with 10 no no because every time + + align:start position:0% +happy with 10 no no because every time + + + align:start position:0% +happy with 10 no no because every time +you don't get there you're dead right so + + align:start position:0% +you don't get there you're dead right so + + + align:start position:0% +you don't get there you're dead right so +you had a little chance of dying and not + + align:start position:0% +you had a little chance of dying and not + + + align:start position:0% +you had a little chance of dying and not +reaching one and a little chance of + + align:start position:0% +reaching one and a little chance of + + + align:start position:0% +reaching one and a little chance of +dying and not going from one to two and + + align:start position:0% +dying and not going from one to two and + + + align:start position:0% +dying and not going from one to two and +you add up all those chances of dying + + align:start position:0% +you add up all those chances of dying + + + align:start position:0% +you add up all those chances of dying +and your toast because that'll be adding + + align:start position:0% +and your toast because that'll be adding + + + align:start position:0% +and your toast because that'll be adding +up to everything pretty + + align:start position:0% +up to everything pretty + + + align:start position:0% +up to everything pretty +much all right so that's a good question + + align:start position:0% +much all right so that's a good question + + + align:start position:0% +much all right so that's a good question +if you're likely to win get up by one + + align:start position:0% +if you're likely to win get up by one + + + align:start position:0% +if you're likely to win get up by one +why aren't you likely to get up by 10 + + align:start position:0% +why aren't you likely to get up by 10 + + + align:start position:0% +why aren't you likely to get up by 10 +yeah it doesn't work that way that's a + + align:start position:0% +yeah it doesn't work that way that's a + + + align:start position:0% +yeah it doesn't work that way that's a +great + + align:start position:0% +great + + + align:start position:0% +great +question let me show you the phenomenon + + align:start position:0% +question let me show you the phenomenon + + + align:start position:0% +question let me show you the phenomenon +that's going on + + align:start position:0% +that's going on + + + align:start position:0% +that's going on +here + + align:start position:0% + + + + align:start position:0% + +uh as to why it works out this way when + + align:start position:0% +uh as to why it works out this way when + + + align:start position:0% +uh as to why it works out this way when +we had the math so we looked at it that + + align:start position:0% +we had the math so we looked at it that + + + align:start position:0% +we had the math so we looked at it that +way and we noticed that one case is a + + align:start position:0% +way and we noticed that one case is a + + + align:start position:0% +way and we noticed that one case is a +double root and the other case isn't and + + align:start position:0% +double root and the other case isn't and + + + align:start position:0% +double root and the other case isn't and +that exponential in the case where you + + align:start position:0% +that exponential in the case where you + + + align:start position:0% +that exponential in the case where you +didn't have that second root at one + + align:start position:0% +didn't have that second root at one + + + align:start position:0% +didn't have that second root at one +makes an enormous difference + + align:start position:0% +makes an enormous difference + + + align:start position:0% +makes an enormous difference +you know qualitatively we can draw the + + align:start position:0% +you know qualitatively we can draw the + + + align:start position:0% +you know qualitatively we can draw the +two + + align:start position:0% +two + + + align:start position:0% +two +cases so in the case of an unbiased or + + align:start position:0% +cases so in the case of an unbiased or + + + align:start position:0% +cases so in the case of an unbiased or +fair + + align:start position:0% + + + + align:start position:0% + +game if we track what's going on over + + align:start position:0% +game if we track what's going on over + + + align:start position:0% +game if we track what's going on over +time and we start with + + align:start position:0% + + + + align:start position:0% + +nll sort of this is our + + align:start position:0% +nll sort of this is our + + + align:start position:0% +nll sort of this is our +Baseline and here's our Target T is n + + align:start position:0% +Baseline and here's our Target T is n + + + align:start position:0% +Baseline and here's our Target T is n +plus + + align:start position:0% +plus + + + align:start position:0% +plus +M and so we quit if we ever get here and + + align:start position:0% +M and so we quit if we ever get here and + + + align:start position:0% +M and so we quit if we ever get here and +we quit if we ever hit the bottom and we + + align:start position:0% +we quit if we ever hit the bottom and we + + + align:start position:0% +we quit if we ever hit the bottom and we +got a random walk you know it's going + + align:start position:0% +got a random walk you know it's going + + + align:start position:0% +got a random walk you know it's going +around you know there's just doing this + + align:start position:0% +around you know there's just doing this + + + align:start position:0% +around you know there's just doing this +kind of stuff and eventually it's going + + align:start position:0% +kind of stuff and eventually it's going + + + align:start position:0% +kind of stuff and eventually it's going +to hit one of these + + align:start position:0% +to hit one of these + + + align:start position:0% +to hit one of these +boundaries and if we're if m is small + + align:start position:0% +boundaries and if we're if m is small + + + align:start position:0% +boundaries and if we're if m is small +compared to + + align:start position:0% +compared to + + + align:start position:0% +compared to +n we're more likely to hit this boundary + + align:start position:0% +n we're more likely to hit this boundary + + + align:start position:0% +n we're more likely to hit this boundary +and in fact the chance we hit this + + align:start position:0% +and in fact the chance we hit this + + + align:start position:0% +and in fact the chance we hit this +boundary first is the like the ratio of + + align:start position:0% +boundary first is the like the ratio of + + + align:start position:0% +boundary first is the like the ratio of +these sizes it's n over the total is a + + align:start position:0% +these sizes it's n over the total is a + + + align:start position:0% +these sizes it's n over the total is a +chance that we hit that one + + align:start position:0% +chance that we hit that one + + + align:start position:0% +chance that we hit that one +first now in the bias + + align:start position:0% +first now in the bias + + + align:start position:0% +first now in the bias +case picture looks + + align:start position:0% + + + + align:start position:0% + +different so in the bias case + + align:start position:0% +different so in the bias case + + + align:start position:0% +different so in the bias case +draw it + + align:start position:0% +draw it + + + align:start position:0% +draw it +here so this is now + + align:start position:0% +here so this is now + + + align:start position:0% +here so this is now +biased and we're going to assume it's + + align:start position:0% +biased and we're going to assume it's + + + align:start position:0% +biased and we're going to assume it's +downward biased you're more likely to + + align:start position:0% + + + + align:start position:0% + +lose so you start at n and you got your + + align:start position:0% +lose so you start at n and you got your + + + align:start position:0% +lose so you start at n and you got your +boundary up here at + + align:start position:0% +boundary up here at + + + align:start position:0% +boundary up here at +tal n plus + + align:start position:0% +tal n plus + + + align:start position:0% +tal n plus +M time is going this + + align:start position:0% +M time is going this + + + align:start position:0% +M time is going this +way the problem is you got + + align:start position:0% +way the problem is you got + + + align:start position:0% +way the problem is you got +a downward sort of + + align:start position:0% +a downward sort of + + + align:start position:0% +a downward sort of +Baseline + + align:start position:0% + + + + align:start position:0% + +because you expect to lose a little bit + + align:start position:0% +because you expect to lose a little bit + + + align:start position:0% +because you expect to lose a little bit +each time and so you're taking these + + align:start position:0% +each time and so you're taking these + + + align:start position:0% +each time and so you're taking these +random + + align:start position:0% +random + + + align:start position:0% +random +walk and you + + align:start position:0% +walk and you + + + align:start position:0% +walk and you +Collide here + + align:start position:0% +Collide here + + + align:start position:0% +Collide here +and these things are known as the the + + align:start position:0% +and these things are known as the the + + + align:start position:0% +and these things are known as the the +swings this is known as the + + align:start position:0% + + + + align:start position:0% + +drift and the drift downward is 1 minus + + align:start position:0% +drift and the drift downward is 1 minus + + + align:start position:0% +drift and the drift downward is 1 minus +2p that's what you expect expect to lose + + align:start position:0% +2p that's what you expect expect to lose + + + align:start position:0% +2p that's what you expect expect to lose +if you did the expected loss on each bet + + align:start position:0% +if you did the expected loss on each bet + + + align:start position:0% +if you did the expected loss on each bet +one minus 2p because you're going to not + + align:start position:0% +one minus 2p because you're going to not + + + align:start position:0% +one minus 2p because you're going to not +be a fair game this one has that has + + align:start position:0% +be a fair game this one has that has + + + align:start position:0% +be a fair game this one has that has +zero drift up there it stays steady and + + align:start position:0% +zero drift up there it stays steady and + + + align:start position:0% +zero drift up there it stays steady and +in random + + align:start position:0% +in random + + + align:start position:0% +in random +walks + + align:start position:0% +walks + + + align:start position:0% +walks +drift + + align:start position:0% + + + + align:start position:0% + +outweighs the + + align:start position:0% +outweighs the + + + align:start position:0% +outweighs the +swings these are the swings here and + + align:start position:0% +swings these are the swings here and + + + align:start position:0% +swings these are the swings here and +they're + + align:start position:0% +they're + + + align:start position:0% +they're +random the drift is deterministic it's + + align:start position:0% +random the drift is deterministic it's + + + align:start position:0% +random the drift is deterministic it's +steadily going down and so almost always + + align:start position:0% +steadily going down and so almost always + + + align:start position:0% +steadily going down and so almost always +in a random walk the drift totally takes + + align:start position:0% +in a random walk the drift totally takes + + + align:start position:0% +in a random walk the drift totally takes +over the swings the swings are small + + align:start position:0% +over the swings the swings are small + + + align:start position:0% +over the swings the swings are small +compared to what you're losing on a + + align:start position:0% +compared to what you're losing on a + + + align:start position:0% +compared to what you're losing on a +steady + + align:start position:0% +steady + + + align:start position:0% +steady +basis all right and that's why the + + align:start position:0% +basis all right and that's why the + + + align:start position:0% +basis all right and that's why the +you're so much more likely to lose when + + align:start position:0% +you're so much more likely to lose when + + + align:start position:0% +you're so much more likely to lose when +you have + + align:start position:0% +you have + + + align:start position:0% +you have +the uh drift + + align:start position:0% +the uh drift + + + align:start position:0% +the uh drift +downward all right just as an example + + align:start position:0% +downward all right just as an example + + + align:start position:0% +downward all right just as an example +maybe putting some numbers around + + align:start position:0% + + + + align:start position:0% + +that the swings are the same in both + + align:start position:0% +that the swings are the same in both + + + align:start position:0% +that the swings are the same in both +cases so let's give you a some + + align:start position:0% +cases so let's give you a some + + + align:start position:0% +cases so let's give you a some +qualification for how big the swings + + align:start position:0% +qualification for how big the swings + + + align:start position:0% +qualification for how big the swings +tend to + + align:start position:0% + + + + align:start position:0% + +be and sort of do that with standard + + align:start position:0% +be and sort of do that with standard + + + align:start position:0% +be and sort of do that with standard +deviation + + align:start position:0% + + + + align:start position:0% + +notation after X bets or X + + align:start position:0% + + + + align:start position:0% + +steps the amount you've drifted or the + + align:start position:0% +steps the amount you've drifted or the + + + align:start position:0% +steps the amount you've drifted or the +expected + + align:start position:0% +expected + + + align:start position:0% +expected +losses 1 minus 2p + + align:start position:0% +losses 1 minus 2p + + + align:start position:0% +losses 1 minus 2p +X and that's maybe we should just + + align:start position:0% +X and that's maybe we should just + + + align:start position:0% +X and that's maybe we should just +understand why this is a case the + + align:start position:0% +understand why this is a case the + + + align:start position:0% +understand why this is a case the +expected return on a + + align:start position:0% + + + + align:start position:0% + +bet is one with probability p and minus + + align:start position:0% +bet is one with probability p and minus + + + align:start position:0% +bet is one with probability p and minus +one with probability one minus + + align:start position:0% +one with probability one minus + + + align:start position:0% +one with probability one minus +p and so that + + align:start position:0% +p and so that + + + align:start position:0% +p and so that +is I get that + + align:start position:0% +is I get that + + + align:start position:0% +is I get that +right I think that's + + align:start position:0% +right I think that's + + + align:start position:0% +right I think that's +right oh is that oh expected loss I'm + + align:start position:0% +right oh is that oh expected loss I'm + + + align:start position:0% +right oh is that oh expected loss I'm +measuring the drift downward instead of + + align:start position:0% +measuring the drift downward instead of + + + align:start position:0% +measuring the drift downward instead of +expected return let's do the loss + + align:start position:0% +expected return let's do the loss + + + align:start position:0% +expected return let's do the loss +because that's the drift as a downward + + align:start position:0% +because that's the drift as a downward + + + align:start position:0% +because that's the drift as a downward +thing + + align:start position:0% +thing + + + align:start position:0% +thing +so the expected loss now you lose a + + align:start position:0% +so the expected loss now you lose a + + + align:start position:0% +so the expected loss now you lose a +dollar with one minus + + align:start position:0% + + + + align:start position:0% + +p and you gain a dollar which is + + align:start position:0% +p and you gain a dollar which is + + + align:start position:0% +p and you gain a dollar which is +negative loss with probability + + align:start position:0% +negative loss with probability + + + align:start position:0% +negative loss with probability +p and so you get 1 minus P minus p is 1 + + align:start position:0% +p and so you get 1 minus P minus p is 1 + + + align:start position:0% +p and so you get 1 minus P minus p is 1 +minus 2 p so that's your expected loss + + align:start position:0% +minus 2 p so that's your expected loss + + + align:start position:0% +minus 2 p so that's your expected loss +your expected winnings are the negative + + align:start position:0% +your expected winnings are the negative + + + align:start position:0% +your expected winnings are the negative +of + + align:start position:0% +of + + + align:start position:0% +of +that so after X steps you expect to + + align:start position:0% +that so after X steps you expect to + + + align:start position:0% +that so after X steps you expect to +lose well just add up the linearity of + + align:start position:0% +lose well just add up the linearity of + + + align:start position:0% +lose well just add up the linearity of +expectation you expect to lose this much + + align:start position:0% +expectation you expect to lose this much + + + align:start position:0% +expectation you expect to lose this much +x times so that's your expected drift + + align:start position:0% +x times so that's your expected drift + + + align:start position:0% +x times so that's your expected drift +you've expected to lose that + + align:start position:0% +you've expected to lose that + + + align:start position:0% +you've expected to lose that +much now the swing and we won't prove + + align:start position:0% +much now the swing and we won't prove + + + align:start position:0% +much now the swing and we won't prove +this the swing is expected to be square + + align:start position:0% +this the swing is expected to be square + + + align:start position:0% +this the swing is expected to be square +root of x times a constant so I've used + + align:start position:0% +root of x times a constant so I've used + + + align:start position:0% +root of x times a constant so I've used +the Theta notation here and the constant + + align:start position:0% +the Theta notation here and the constant + + + align:start position:0% +the Theta notation here and the constant +is small if I take X consecutive bets + + align:start position:0% +is small if I take X consecutive bets + + + align:start position:0% +is small if I take X consecutive bets +for a + + align:start position:0% +for a + + + align:start position:0% +for a +dollar I'm very likely to be about + + align:start position:0% +dollar I'm very likely to be about + + + align:start position:0% +dollar I'm very likely to be about +square root of x off of the expected + + align:start position:0% +square root of x off of the expected + + + align:start position:0% +square root of x off of the expected +drift and you can see that this is + + align:start position:0% +drift and you can see that this is + + + align:start position:0% +drift and you can see that this is +square + + align:start position:0% +square + + + align:start position:0% +square +root that is linear so this totally + + align:start position:0% +root that is linear so this totally + + + align:start position:0% +root that is linear so this totally +dominates that so the swings are + + align:start position:0% +dominates that so the swings are + + + align:start position:0% +dominates that so the swings are +generally not enough to save you and so + + align:start position:0% +generally not enough to save you and so + + + align:start position:0% +generally not enough to save you and so +you're just going to cruise downward and + + align:start position:0% +you're just going to cruise downward and + + + align:start position:0% +you're just going to cruise downward and +crash almost + + align:start position:0% + + + + align:start position:0% + +surely okay any + + align:start position:0% +surely okay any + + + align:start position:0% +surely okay any +questions about that + + align:start position:0% + + + + align:start position:0% + +okay all right so we figured out the + + align:start position:0% +okay all right so we figured out the + + + align:start position:0% +okay all right so we figured out the +probability of winning MLL before going + + align:start position:0% +probability of winning MLL before going + + + align:start position:0% +probability of winning MLL before going +broke that's that's done with + + align:start position:0% +broke that's that's done with + + + align:start position:0% +broke that's that's done with +um now this means it's logical conclude + + align:start position:0% +um now this means it's logical conclude + + + align:start position:0% +um now this means it's logical conclude +you're likely to go home broke in an + + align:start position:0% +you're likely to go home broke in an + + + align:start position:0% +you're likely to go home broke in an +unfair + + align:start position:0% +unfair + + + align:start position:0% +unfair +game um actually before we do that + + align:start position:0% +game um actually before we do that + + + align:start position:0% +game um actually before we do that +there's one other case we got to rule + + align:start position:0% +there's one other case we got to rule + + + align:start position:0% +there's one other case we got to rule +out we proved you're likely not to go + + align:start position:0% +out we proved you're likely not to go + + + align:start position:0% +out we proved you're likely not to go +home a winner does that necessarily mean + + align:start position:0% +home a winner does that necessarily mean + + + align:start position:0% +home a winner does that necessarily mean +you're likely to go broke I've been + + align:start position:0% +you're likely to go broke I've been + + + align:start position:0% +you're likely to go broke I've been +saying that but is there's some other + + align:start position:0% +saying that but is there's some other + + + align:start position:0% +saying that but is there's some other +thing we should + + align:start position:0% +thing we should + + + align:start position:0% +thing we should +check let one way you might not go home + + align:start position:0% + + + + align:start position:0% + +broke what is it you don't go home and + + align:start position:0% +broke what is it you don't go home and + + + align:start position:0% +broke what is it you don't go home and +why would you not go + + align:start position:0% +why would you not go + + + align:start position:0% +why would you not go +home yeah playing forever you're playing + + align:start position:0% +home yeah playing forever you're playing + + + align:start position:0% +home yeah playing forever you're playing +forever all right we didn't rule out + + align:start position:0% +forever all right we didn't rule out + + + align:start position:0% +forever all right we didn't rule out +that case that you're playing forever + + align:start position:0% +that case that you're playing forever + + + align:start position:0% +that case that you're playing forever +but it turns out if you did the same + + align:start position:0% +but it turns out if you did the same + + + align:start position:0% +but it turns out if you did the same +analysis you could analyze the + + align:start position:0% +analysis you could analyze the + + + align:start position:0% +analysis you could analyze the +probability of going home broke and when + + align:start position:0% +probability of going home broke and when + + + align:start position:0% +probability of going home broke and when +you add it to the probabil of going home + + align:start position:0% +you add it to the probabil of going home + + + align:start position:0% +you add it to the probabil of going home +a winner it adds to one which means the + + align:start position:0% +a winner it adds to one which means the + + + align:start position:0% +a winner it adds to one which means the +probability of playing forever is + + align:start position:0% +probability of playing forever is + + + align:start position:0% +probability of playing forever is +zero now there are sample points where + + align:start position:0% +zero now there are sample points where + + + align:start position:0% +zero now there are sample points where +you play forever but when you add up all + + align:start position:0% +you play forever but when you add up all + + + align:start position:0% +you play forever but when you add up all +those sample points if their probability + + align:start position:0% +those sample points if their probability + + + align:start position:0% +those sample points if their probability +is zero we ignore them and we say it + + align:start position:0% +is zero we ignore them and we say it + + + align:start position:0% +is zero we ignore them and we say it +can't happen now we're bordering on + + align:start position:0% +can't happen now we're bordering on + + + align:start position:0% +can't happen now we're bordering on +philosophy here okay because there is a + + align:start position:0% +philosophy here okay because there is a + + + align:start position:0% +philosophy here okay because there is a +sample point you could win lose win lose + + align:start position:0% +sample point you could win lose win lose + + + align:start position:0% +sample point you could win lose win lose +win lose forever but because you add + + align:start position:0% +win lose forever but because you add + + + align:start position:0% +win lose forever but because you add +them all up at zero measure Theory and + + align:start position:0% +them all up at zero measure Theory and + + + align:start position:0% +them all up at zero measure Theory and +some math we're not going to get into + + align:start position:0% +some math we're not going to get into + + + align:start position:0% +some math we're not going to get into +tells you it doesn't happen all right + + align:start position:0% +tells you it doesn't happen all right + + + align:start position:0% +tells you it doesn't happen all right +it's probability one you're a winner or + + align:start position:0% +it's probability one you're a winner or + + + align:start position:0% +it's probability one you're a winner or +a + + align:start position:0% +a + + + align:start position:0% +a +loser + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +um all right so I'm not gonna not going + + align:start position:0% +um all right so I'm not gonna not going + + + align:start position:0% +um all right so I'm not gonna not going +to prove that that the probability you + + align:start position:0% +to prove that that the probability you + + + align:start position:0% +to prove that that the probability you +play Forever is + + align:start position:0% + + + + align:start position:0% + +zero all right but let's look at how + + align:start position:0% +zero all right but let's look at how + + + align:start position:0% +zero all right but let's look at how +long you play + + align:start position:0% +long you play + + + align:start position:0% +long you play +how long does it take you to go home one + + align:start position:0% +how long does it take you to go home one + + + align:start position:0% +how long does it take you to go home one +way or another go + + align:start position:0% +way or another go + + + align:start position:0% +way or another go +broke and uh to do this we're going to + + align:start position:0% +broke and uh to do this we're going to + + + align:start position:0% +broke and uh to do this we're going to +set up another + + align:start position:0% + + + + align:start position:0% + +recurrence so we know eventually we hit + + align:start position:0% +recurrence so we know eventually we hit + + + align:start position:0% +recurrence so we know eventually we hit +a boundary I want to know how many bets + + align:start position:0% +a boundary I want to know how many bets + + + align:start position:0% +a boundary I want to know how many bets +does it take to hit the + + align:start position:0% +does it take to hit the + + + align:start position:0% +does it take to hit the +boundary how long do we get to play + + align:start position:0% +boundary how long do we get to play + + + align:start position:0% +boundary how long do we get to play +before we go home on + + align:start position:0% +before we go home on + + + align:start position:0% +before we go home on +unhappy so the S will be the number of + + align:start position:0% +unhappy so the S will be the number of + + + align:start position:0% +unhappy so the S will be the number of +steps + + align:start position:0% +steps + + + align:start position:0% +steps +until we hit a + + align:start position:0% + + + + align:start position:0% + +boundary and I want to know the expected + + align:start position:0% +boundary and I want to know the expected + + + align:start position:0% +boundary and I want to know the expected +number I'll call it Isa here is the + + align:start position:0% +number I'll call it Isa here is the + + + align:start position:0% +number I'll call it Isa here is the +expected value of s given that I start + + align:start position:0% +expected value of s given that I start + + + align:start position:0% +expected value of s given that I start +with + + align:start position:0% + + + + align:start position:0% + +n i mean the reason you could think + + align:start position:0% +n i mean the reason you could think + + + align:start position:0% +n i mean the reason you could think +about this is you know we know we're + + align:start position:0% +about this is you know we know we're + + + align:start position:0% +about this is you know we know we're +going to go home broke pretty pretty + + align:start position:0% +going to go home broke pretty pretty + + + align:start position:0% +going to go home broke pretty pretty +likely do we at least have some fun in + + align:start position:0% +likely do we at least have some fun in + + + align:start position:0% +likely do we at least have some fun in +the meantime do we get a lot of gambling + + align:start position:0% +the meantime do we get a lot of gambling + + + align:start position:0% +the meantime do we get a lot of gambling +in in free drinks or whatever before + + align:start position:0% +in in free drinks or whatever before + + + align:start position:0% +in in free drinks or whatever before +we're we're killed + + align:start position:0% + + + + align:start position:0% + +here now this also has a recurrence and + + align:start position:0% +here now this also has a recurrence and + + + align:start position:0% +here now this also has a recurrence and +I'm going to show you what it is then + + align:start position:0% +I'm going to show you what it is then + + + align:start position:0% +I'm going to show you what it is then +prove that that's correct so I claim + + align:start position:0% +prove that that's correct so I claim + + + align:start position:0% +prove that that's correct so I claim +that the expected number of steps given + + align:start position:0% +that the expected number of steps given + + + align:start position:0% +that the expected number of steps given +we start with nll is well zero if we + + align:start position:0% +we start with nll is well zero if we + + + align:start position:0% +we start with nll is well zero if we +start with no + + align:start position:0% +start with no + + + align:start position:0% +start with no +money because we already broke it's zero + + align:start position:0% +money because we already broke it's zero + + + align:start position:0% +money because we already broke it's zero +if we + + align:start position:0% +if we + + + align:start position:0% +if we +start with T + + align:start position:0% +start with T + + + align:start position:0% +start with T +because then we just go home Happy + + align:start position:0% +because then we just go home Happy + + + align:start position:0% +because then we just go home Happy +there's no bets because we've already + + align:start position:0% +there's no bets because we've already + + + align:start position:0% +there's no bets because we've already +hit the upper + + align:start position:0% +hit the upper + + + align:start position:0% +hit the upper +boundary and the interesting case will + + align:start position:0% +boundary and the interesting case will + + + align:start position:0% +boundary and the interesting case will +be it's 1 + P + + align:start position:0% +be it's 1 + P + + + align:start position:0% +be it's 1 + P +* e + + align:start position:0% +* e + + + align:start position:0% +* e +nus1 + 1 - + + align:start position:0% +nus1 + 1 - + + + align:start position:0% +nus1 + 1 - +P up n + one 1 minus p e n minus one if + + align:start position:0% +P up n + one 1 minus p e n minus one if + + + align:start position:0% +P up n + one 1 minus p e n minus one if +we start with between zero and + + align:start position:0% + + + + align:start position:0% + +T + + align:start position:0% +T + + + align:start position:0% +T +okay so let's prove + + align:start position:0% + + + + align:start position:0% + +that actually the + + align:start position:0% +that actually the + + + align:start position:0% +that actually the +proof is exactly the same as the last + + align:start position:0% +proof is exactly the same as the last + + + align:start position:0% +proof is exactly the same as the last +one so I don't think I need to do + + align:start position:0% + + + + align:start position:0% + +it all right the proof is is pretty + + align:start position:0% +it all right the proof is is pretty + + + align:start position:0% +it all right the proof is is pretty +simple because we look at two cases you + + align:start position:0% +simple because we look at two cases you + + + align:start position:0% +simple because we look at two cases you +win the first + + align:start position:0% +win the first + + + align:start position:0% +win the first +bet happens with probability p and then + + align:start position:0% +bet happens with probability p and then + + + align:start position:0% +bet happens with probability p and then +you're starting with n plus1 over again + + align:start position:0% +you're starting with n plus1 over again + + + align:start position:0% +you're starting with n plus1 over again +or you lose the first bet happens with + + align:start position:0% +or you lose the first bet happens with + + + align:start position:0% +or you lose the first bet happens with +probability one minus p and you're + + align:start position:0% +probability one minus p and you're + + + align:start position:0% +probability one minus p and you're +starting over with n minus $1 now same + + align:start position:0% +starting over with n minus $1 now same + + + align:start position:0% +starting over with n minus $1 now same +as last time in fact this whole + + align:start position:0% +as last time in fact this whole + + + align:start position:0% +as last time in fact this whole +recurrence is identical to last time + + align:start position:0% +recurrence is identical to last time + + + align:start position:0% +recurrence is identical to last time +except for one + + align:start position:0% +except for one + + + align:start position:0% +except for one +thing what's the one thing that's + + align:start position:0% +thing what's the one thing that's + + + align:start position:0% +thing what's the one thing that's +different + + align:start position:0% +different + + + align:start position:0% +different +now what is + + align:start position:0% + + + + align:start position:0% + +it you + + align:start position:0% +it you + + + align:start position:0% +it you +have so + + align:start position:0% +have so + + + align:start position:0% +have so +it's that's + + align:start position:0% +it's that's + + + align:start position:0% +it's that's +different there's another difference + + align:start position:0% +different there's another difference + + + align:start position:0% +different there's another difference +that's one difference that's going to + + align:start position:0% +that's one difference that's going to + + + align:start position:0% +that's one difference that's going to +make it inhomogeneous that's sort of a + + align:start position:0% +make it inhomogeneous that's sort of a + + + align:start position:0% +make it inhomogeneous that's sort of a +pain what's the other difference from + + align:start position:0% +pain what's the other difference from + + + align:start position:0% +pain what's the other difference from +last time this part's the same + + align:start position:0% +last time this part's the same + + + align:start position:0% +last time this part's the same +otherwise what is it boundary conditions + + align:start position:0% +otherwise what is it boundary conditions + + + align:start position:0% +otherwise what is it boundary conditions +that was a one before now it's a + + align:start position:0% +that was a one before now it's a + + + align:start position:0% +that was a one before now it's a +zero okay so I little change here and I + + align:start position:0% +zero okay so I little change here and I + + + align:start position:0% +zero okay so I little change here and I +added a one here uh but that's going to + + align:start position:0% +added a one here uh but that's going to + + + align:start position:0% +added a one here uh but that's going to +make it a pretty different answer so + + align:start position:0% +make it a pretty different answer so + + + align:start position:0% +make it a pretty different answer so +let's see what the recurrence is I'll + + align:start position:0% +let's see what the recurrence is I'll + + + align:start position:0% +let's see what the recurrence is I'll +rearrange rearrange terms here to put it + + align:start position:0% +rearrange rearrange terms here to put it + + + align:start position:0% +rearrange rearrange terms here to put it +into recurrence + + align:start position:0% +into recurrence + + + align:start position:0% +into recurrence +I get p e subn + 1 minus e n + 1- p n + + align:start position:0% +I get p e subn + 1 minus e n + 1- p n + + + align:start position:0% +I get p e subn + 1 minus e n + 1- p n +minus one equals minus1 not zero and the + + align:start position:0% +minus one equals minus1 not zero and the + + + align:start position:0% +minus one equals minus1 not zero and the +boundary conditions are e0 is zero and e + + align:start position:0% +boundary conditions are e0 is zero and e + + + align:start position:0% +boundary conditions are e0 is zero and e +t is + + align:start position:0% + + + + align:start position:0% + +zero + + align:start position:0% +zero + + + align:start position:0% +zero +okay what's the first thing you do when + + align:start position:0% +okay what's the first thing you do when + + + align:start position:0% +okay what's the first thing you do when +you have an inhomogeneous linear + + align:start position:0% +you have an inhomogeneous linear + + + align:start position:0% +you have an inhomogeneous linear +recurrence solve the homogeneous + + align:start position:0% +recurrence solve the homogeneous + + + align:start position:0% +recurrence solve the homogeneous +one and the answer there well it's the + + align:start position:0% +one and the answer there well it's the + + + align:start position:0% +one and the answer there well it's the +same as before this is the part we + + align:start position:0% +same as before this is the part we + + + align:start position:0% +same as before this is the part we +analyzed and we'll do it for the case + + align:start position:0% +analyzed and we'll do it for the case + + + align:start position:0% +analyzed and we'll do it for the case +when p is not a half so the unfair + + align:start position:0% +when p is not a half so the unfair + + + align:start position:0% +when p is not a half so the unfair +game so the homogeneous + + align:start position:0% + + + + align:start position:0% + +solution Isen just from before same + + align:start position:0% +solution Isen just from before same + + + align:start position:0% +solution Isen just from before same +thing 1 - p over P to the N plus b and + + align:start position:0% +thing 1 - p over P to the N plus b and + + + align:start position:0% +thing 1 - p over P to the N plus b and +this is the case with two roots P does + + align:start position:0% +this is the case with two roots P does + + + align:start position:0% +this is the case with two roots P does +not equal a + + align:start position:0% + + + + align:start position:0% + +half what's the next thing you + + align:start position:0% +half what's the next thing you + + + align:start position:0% +half what's the next thing you +do for in homogeneous + + align:start position:0% +do for in homogeneous + + + align:start position:0% +do for in homogeneous +recurrence are we plugging in boundary + + align:start position:0% +recurrence are we plugging in boundary + + + align:start position:0% +recurrence are we plugging in boundary +conditions + + align:start position:0% +conditions + + + align:start position:0% +conditions +yet no so what do I do + + align:start position:0% +yet no so what do I do + + + align:start position:0% +yet no so what do I do +next particular + + align:start position:0% + + + + align:start position:0% + +solution and what's my first + + align:start position:0% +solution and what's my first + + + align:start position:0% +solution and what's my first +guess with + + align:start position:0% + + + + align:start position:0% + +recurrence like this + + align:start position:0% + + + + align:start position:0% + +here what do I guess for + + align:start position:0% +here what do I guess for + + + align:start position:0% +here what do I guess for +n I'm trying to guess something that + + align:start position:0% +n I'm trying to guess something that + + + align:start position:0% +n I'm trying to guess something that +looks like + + align:start position:0% +looks like + + + align:start position:0% +looks like +that so what do I + + align:start position:0% +that so what do I + + + align:start position:0% +that so what do I +guess constant yeah something just + + align:start position:0% +guess constant yeah something just + + + align:start position:0% +guess constant yeah something just +that's a scalar I'll just guess a + + align:start position:0% +that's a scalar I'll just guess a + + + align:start position:0% +that's a scalar I'll just guess a +constant and if I plug a constant a into + + align:start position:0% +constant and if I plug a constant a into + + + align:start position:0% +constant and if I plug a constant a into +here it's going to f + + align:start position:0% +here it's going to f + + + align:start position:0% +here it's going to f +CU I'll just get pull the A out I'll get + + align:start position:0% +CU I'll just get pull the A out I'll get + + + align:start position:0% +CU I'll just get pull the A out I'll get +p minus1 plus one minus p is zero and + + align:start position:0% +p minus1 plus one minus p is zero and + + + align:start position:0% +p minus1 plus one minus p is zero and +Zer doesn't equal minus one so it + + align:start position:0% + + + + align:start position:0% + +fails so I guess again what do I guess + + align:start position:0% +fails so I guess again what do I guess + + + align:start position:0% +fails so I guess again what do I guess +next + + align:start position:0% +next + + + align:start position:0% +next +time a n plus + + align:start position:0% + + + + align:start position:0% + +b all right and I don't think I'll drag + + align:start position:0% +b all right and I don't think I'll drag + + + align:start position:0% +b all right and I don't think I'll drag +you through all the uh algebra for that + + align:start position:0% +you through all the uh algebra for that + + + align:start position:0% +you through all the uh algebra for that +but it works + + align:start position:0% +but it works + + + align:start position:0% +but it works +works and when you do it you find + + align:start position:0% +works and when you do it you find + + + align:start position:0% +works and when you do it you find +that a is min-1 over 2 p minus one and B + + align:start position:0% +that a is min-1 over 2 p minus one and B + + + align:start position:0% +that a is min-1 over 2 p minus one and B +could be anything + + align:start position:0% +could be anything + + + align:start position:0% +could be anything +so let me just rewrite this as 1 over 1 + + align:start position:0% +so let me just rewrite this as 1 over 1 + + + align:start position:0% +so let me just rewrite this as 1 over 1 +minus 2 p and B can be anything so we'll + + align:start position:0% +minus 2 p and B can be anything so we'll + + + align:start position:0% +minus 2 p and B can be anything so we'll +set b equal to + + align:start position:0% + + + + align:start position:0% + +zero all right so we've got our + + align:start position:0% +zero all right so we've got our + + + align:start position:0% +zero all right so we've got our +particular + + align:start position:0% +particular + + + align:start position:0% +particular +solution it's not hard to go compute + + align:start position:0% +solution it's not hard to go compute + + + align:start position:0% +solution it's not hard to go compute +that you just plug it plug it back in + + align:start position:0% + + + + align:start position:0% + +solve okay + + align:start position:0% + + + + align:start position:0% + +so now we add them together to get the + + align:start position:0% +so now we add them together to get the + + + align:start position:0% +so now we add them together to get the +general + + align:start position:0% + + + + align:start position:0% + +solution this is a n plus b b was zero + + align:start position:0% +solution this is a n plus b b was zero + + + align:start position:0% +solution this is a n plus b b was zero +and here's a as 1 over 1 - + + align:start position:0% +and here's a as 1 over 1 - + + + align:start position:0% +and here's a as 1 over 1 - +2p and now what do we + + align:start position:0% +2p and now what do we + + + align:start position:0% +2p and now what do we +do to finish I got my general solution + + align:start position:0% + + + + align:start position:0% + +here I adding up the homogeneous in the + + align:start position:0% +here I adding up the homogeneous in the + + + align:start position:0% +here I adding up the homogeneous in the +particular + + align:start position:0% +particular + + + align:start position:0% +particular +solution plug in the boundary + + align:start position:0% + + + + align:start position:0% + +conditions all right I'm not going to + + align:start position:0% +conditions all right I'm not going to + + + align:start position:0% +conditions all right I'm not going to +drag you through solving this case but + + align:start position:0% +drag you through solving this case but + + + align:start position:0% +drag you through solving this case but +I'm going to show you the + + align:start position:0% + + + + align:start position:0% + +answer = n over 1 - + + align:start position:0% +answer = n over 1 - + + + align:start position:0% +answer = n over 1 - +2p oops minus t the upper boundary over + + align:start position:0% +2p oops minus t the upper boundary over + + + align:start position:0% +2p oops minus t the upper boundary over +1 - 2 + + align:start position:0% +1 - 2 + + + align:start position:0% +1 - 2 +p Time 1 - p over P the + + align:start position:0% +p Time 1 - p over P the + + + align:start position:0% +p Time 1 - p over P the +nus1 + + align:start position:0% +nus1 + + + align:start position:0% +nus1 +over 1us p over P to the T minus one so + + align:start position:0% +over 1us p over P to the T minus one so + + + align:start position:0% +over 1us p over P to the T minus one so +actually this looks a little familiar + + align:start position:0% +actually this looks a little familiar + + + align:start position:0% +actually this looks a little familiar +from the last time when we did this + + align:start position:0% +from the last time when we did this + + + align:start position:0% +from the last time when we did this +recurrence figuring out the probability + + align:start position:0% +recurrence figuring out the probability + + + align:start position:0% +recurrence figuring out the probability +we go home a winner here this is the + + align:start position:0% +we go home a winner here this is the + + + align:start position:0% +we go home a winner here this is the +expected number of steps to hit a + + align:start position:0% +expected number of steps to hit a + + + align:start position:0% +expected number of steps to hit a +boundary to go + + align:start position:0% +boundary to go + + + align:start position:0% +boundary to go +home if we plug in the values it's a + + align:start position:0% +home if we plug in the values it's a + + + align:start position:0% +home if we plug in the values it's a +little hairy but you can compute + + align:start position:0% +little hairy but you can compute + + + align:start position:0% +little hairy but you can compute +it so for example if m is + + align:start position:0% +it so for example if m is + + + align:start position:0% +it so for example if m is +100 N is a + + align:start position:0% +100 N is a + + + align:start position:0% +100 N is a +th000 t would be 1100 in that + + align:start position:0% +th000 t would be 1100 in that + + + align:start position:0% +th000 t would be 1100 in that +case p is + + align:start position:0% +case p is + + + align:start position:0% +case p is +9/19 playing + + align:start position:0% +9/19 playing + + + align:start position:0% +9/19 playing +roulette then the expected number of + + align:start position:0% +roulette then the expected number of + + + align:start position:0% +roulette then the expected number of +bets + + align:start position:0% +bets + + + align:start position:0% +bets +before you have to go + + align:start position:0% +before you have to go + + + align:start position:0% +before you have to go +home + + align:start position:0% +home + + + align:start position:0% +home +is 1900 from this + + align:start position:0% + + + + align:start position:0% + +part + + align:start position:0% +part + + + align:start position:0% +part +minus + + align:start position:0% +minus + + + align:start position:0% +minus +0.56 from that + + align:start position:0% +0.56 from that + + + align:start position:0% +0.56 from that +part okay so actually 19,000 sorry so + + align:start position:0% +part okay so actually 19,000 sorry so + + + align:start position:0% +part okay so actually 19,000 sorry so +it's very close to + + align:start position:0% +it's very close to + + + align:start position:0% +it's very close to +19,000 bets you got to + + align:start position:0% +19,000 bets you got to + + + align:start position:0% +19,000 bets you got to +make all right so it takes a long time + + align:start position:0% +make all right so it takes a long time + + + align:start position:0% +make all right so it takes a long time +to lose a th000 bucks and it sort of + + align:start position:0% +to lose a th000 bucks and it sort of + + + align:start position:0% +to lose a th000 bucks and it sort of +comes very close to the answer you would + + align:start position:0% +comes very close to the answer you would + + + align:start position:0% +comes very close to the answer you would +have guessed without thinking and + + align:start position:0% +have guessed without thinking and + + + align:start position:0% +have guessed without thinking and +solving the recurrence if you expect to + + align:start position:0% +solving the recurrence if you expect to + + + align:start position:0% +solving the recurrence if you expect to +lose one minus 2 p every + + align:start position:0% +lose one minus 2 p every + + + align:start position:0% +lose one minus 2 p every +bet and you want to know how long the + + align:start position:0% +bet and you want to know how long the + + + align:start position:0% +bet and you want to know how long the +expected time to lose n doll you might + + align:start position:0% +expected time to lose n doll you might + + + align:start position:0% +expected time to lose n doll you might +well have said I think it's going to be + + align:start position:0% +well have said I think it's going to be + + + align:start position:0% +well have said I think it's going to be +n over the amount I lose every + + align:start position:0% +n over the amount I lose every + + + align:start position:0% +n over the amount I lose every +time that would be wrong + + align:start position:0% +time that would be wrong + + + align:start position:0% +time that would be wrong +technically because you'd have left off + + align:start position:0% +technically because you'd have left off + + + align:start position:0% +technically because you'd have left off +this nasty thing but this nasty thing + + align:start position:0% +this nasty thing but this nasty thing + + + align:start position:0% +this nasty thing but this nasty thing +doesn't make much of a real difference + + align:start position:0% +doesn't make much of a real difference + + + align:start position:0% +doesn't make much of a real difference +because it goes to zero really fast for + + align:start position:0% +because it goes to zero really fast for + + + align:start position:0% +because it goes to zero really fast for +any numbers like 100 and a thousand + + align:start position:0% +any numbers like 100 and a thousand + + + align:start position:0% +any numbers like 100 and a thousand +makes no difference at all so the + + align:start position:0% +makes no difference at all so the + + + align:start position:0% +makes no difference at all so the +intuition in that case comes out to be + + align:start position:0% +intuition in that case comes out to be + + + align:start position:0% +intuition in that case comes out to be +pretty close even though technically + + align:start position:0% +pretty close even though technically + + + align:start position:0% +pretty close even though technically +it's not exactly + + align:start position:0% +it's not exactly + + + align:start position:0% +it's not exactly +right now to see why this goes to + + align:start position:0% +right now to see why this goes to + + + align:start position:0% +right now to see why this goes to +zero if T equals n plus M here this is n + + align:start position:0% +zero if T equals n plus M here this is n + + + align:start position:0% +zero if T equals n plus M here this is n +plus + + align:start position:0% +plus + + + align:start position:0% +plus +M and your upper limit say goes to + + align:start position:0% +M and your upper limit say goes to + + + align:start position:0% +M and your upper limit say goes to +Infinity it's 100 in this case then that + + align:start position:0% +Infinity it's 100 in this case then that + + + align:start position:0% +Infinity it's 100 in this case then that +just zooms to zero and you're only left + + align:start position:0% +just zooms to zero and you're only left + + + align:start position:0% +just zooms to zero and you're only left +with that which means that we can use + + align:start position:0% +with that which means that we can use + + + align:start position:0% +with that which means that we can use +ASM totic notation + + align:start position:0% +ASM totic notation + + + align:start position:0% +ASM totic notation +here to sort of characterize the + + align:start position:0% +here to sort of characterize the + + + align:start position:0% +here to sort of characterize the +expected number of + + align:start position:0% + + + + align:start position:0% + +bets and it's totally dominated by the + + align:start position:0% +bets and it's totally dominated by the + + + align:start position:0% +bets and it's totally dominated by the +drift so as M goes to + + align:start position:0% +drift so as M goes to + + + align:start position:0% +drift so as M goes to +Infinity the expected time to live here + + align:start position:0% +Infinity the expected time to live here + + + align:start position:0% +Infinity the expected time to live here +is + + align:start position:0% +is + + + align:start position:0% +is +Tilda n/ 1 - 2p if you've got + + align:start position:0% +Tilda n/ 1 - 2p if you've got + + + align:start position:0% +Tilda n/ 1 - 2p if you've got +n losing one minus 2 p every time then + + align:start position:0% +n losing one minus 2 p every time then + + + align:start position:0% +n losing one minus 2 p every time then +you last for n over one minus 2p + + align:start position:0% +you last for n over one minus 2p + + + align:start position:0% +you last for n over one minus 2p +steps + + align:start position:0% +steps + + + align:start position:0% +steps +okay now actually what situation in + + align:start position:0% +okay now actually what situation in + + + align:start position:0% +okay now actually what situation in +words does m going to infinity mean say + + align:start position:0% +words does m going to infinity mean say + + + align:start position:0% +words does m going to infinity mean say +I set M to be + + align:start position:0% +I set M to be + + + align:start position:0% +I set M to be +Infinity what what what is that kind of + + align:start position:0% +Infinity what what what is that kind of + + + align:start position:0% +Infinity what what what is that kind of +game if M's Infinity how long am I + + align:start position:0% +game if M's Infinity how long am I + + + align:start position:0% +game if M's Infinity how long am I +playing now yeah now you're playing for + + align:start position:0% +playing now yeah now you're playing for + + + align:start position:0% +playing now yeah now you're playing for +as long as it takes you to lose all of + + align:start position:0% +as long as it takes you to lose all of + + + align:start position:0% +as long as it takes you to lose all of +your money yes all right because there + + align:start position:0% +your money yes all right because there + + + align:start position:0% +your money yes all right because there +is no stopping condition up here going + + align:start position:0% +is no stopping condition up here going + + + align:start position:0% +is no stopping condition up here going +home happy I'm going to play Forever or + + align:start position:0% +home happy I'm going to play Forever or + + + align:start position:0% +home happy I'm going to play Forever or +until I lose + + align:start position:0% +until I lose + + + align:start position:0% +until I lose +everything and this says how long you + + align:start position:0% +everything and this says how long you + + + align:start position:0% +everything and this says how long you +expect to + + align:start position:0% +expect to + + + align:start position:0% +expect to +play all right it's a little less than n + + align:start position:0% +play all right it's a little less than n + + + align:start position:0% +play all right it's a little less than n +over one minus + + align:start position:0% +over one minus + + + align:start position:0% +over one minus +2p uh so if you play until you go broke + + align:start position:0% +2p uh so if you play until you go broke + + + align:start position:0% +2p uh so if you play until you go broke +that's how long you expect to play + + align:start position:0% +that's how long you expect to play + + + align:start position:0% +that's how long you expect to play +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +um so that's that sort of makes sense in + + align:start position:0% +um so that's that sort of makes sense in + + + align:start position:0% +um so that's that sort of makes sense in +that scenario that's not one where it + + align:start position:0% +that scenario that's not one where it + + + align:start position:0% +that scenario that's not one where it +surprises You by + + align:start position:0% +surprises You by + + + align:start position:0% +surprises You by +intuition it is interesting to consider + + align:start position:0% +intuition it is interesting to consider + + + align:start position:0% +intuition it is interesting to consider +the case of a fair game because there's + + align:start position:0% +the case of a fair game because there's + + + align:start position:0% +the case of a fair game because there's +a something that's non-intuitive that + + align:start position:0% +a something that's non-intuitive that + + + align:start position:0% +a something that's non-intuitive that +happens there so in a fair game p is a + + align:start position:0% +happens there so in a fair game p is a + + + align:start position:0% +happens there so in a fair game p is a +half now if I plug in a half + + align:start position:0% +half now if I plug in a half + + + align:start position:0% +half now if I plug in a half +here well I divide by + + align:start position:0% +here well I divide by + + + align:start position:0% +here well I divide by +zero I expect to play forever let's see + + align:start position:0% +zero I expect to play forever let's see + + + align:start position:0% +zero I expect to play forever let's see +if that really I that's not a good way + + align:start position:0% +if that really I that's not a good way + + + align:start position:0% +if that really I that's not a good way +to do the analysis that you get to a + + align:start position:0% +to do the analysis that you get to a + + + align:start position:0% +to do the analysis that you get to a +divide by zero let's actually go back + + align:start position:0% +divide by zero let's actually go back + + + align:start position:0% +divide by zero let's actually go back +and look at this for the case when p is + + align:start position:0% +and look at this for the case when p is + + + align:start position:0% +and look at this for the case when p is +a + + align:start position:0% + + + + align:start position:0% + +half and see what happens in a fair game + + align:start position:0% +half and see what happens in a fair game + + + align:start position:0% +half and see what happens in a fair game +how long you expect to play in a fair + + align:start position:0% +how long you expect to play in a fair + + + align:start position:0% +how long you expect to play in a fair +game then the homogeneous + + align:start position:0% + + + + align:start position:0% + +solution is the simple case e is a n + + align:start position:0% +solution is the simple case e is a n + + + align:start position:0% +solution is the simple case e is a n +plus b you got a double root at + + align:start position:0% +plus b you got a double root at + + + align:start position:0% +plus b you got a double root at +one which we don't have to worry about + + align:start position:0% +one which we don't have to worry about + + + align:start position:0% +one which we don't have to worry about +one the + + align:start position:0% +one the + + + align:start position:0% +one the +N when you do your particular + + align:start position:0% + + + + align:start position:0% + +solution you'll + + align:start position:0% +solution you'll + + + align:start position:0% +solution you'll +try a single + + align:start position:0% +try a single + + + align:start position:0% +try a single +scaler and it fails actually use lower + + align:start position:0% +scaler and it fails actually use lower + + + align:start position:0% +scaler and it fails actually use lower +case a + + align:start position:0% +case a + + + align:start position:0% +case a +fails you will then + + align:start position:0% +fails you will then + + + align:start position:0% +fails you will then +try a degree 1 + + align:start position:0% +try a degree 1 + + + align:start position:0% +try a degree 1 +polom and that will fail what are you + + align:start position:0% +polom and that will fail what are you + + + align:start position:0% +polom and that will fail what are you +going to try + + align:start position:0% +going to try + + + align:start position:0% +going to try +next second degree + + align:start position:0% + + + + align:start position:0% + +polinomial and that will + + align:start position:0% +polinomial and that will + + + align:start position:0% +polinomial and that will +work okay and the answer you + + align:start position:0% + + + + align:start position:0% + +get when you do + + align:start position:0% + + + + align:start position:0% + +that is that I'll put the answer here it + + align:start position:0% +that is that I'll put the answer here it + + + align:start position:0% +that is that I'll put the answer here it +turns out that a is minus one and B and + + align:start position:0% +turns out that a is minus one and B and + + + align:start position:0% +turns out that a is minus one and B and +C can be zero so it's just going to be + + align:start position:0% +C can be zero so it's just going to be + + + align:start position:0% +C can be zero so it's just going to be +minus n^2 for the particular + + align:start position:0% +minus n^2 for the particular + + + align:start position:0% +minus n^2 for the particular +solution that means your general + + align:start position:0% +solution that means your general + + + align:start position:0% +solution that means your general +solution + + align:start position:0% +solution + + + align:start position:0% +solution +is a n + B minus n + + align:start position:0% +is a n + B minus n + + + align:start position:0% +is a n + B minus n +2 now you do your boundary + + align:start position:0% + + + + align:start position:0% + +condition all right you have e0 is + + align:start position:0% +condition all right you have e0 is + + + align:start position:0% +condition all right you have e0 is +zero plug in zero for n that's equal to + + align:start position:0% +zero plug in zero for n that's equal to + + + align:start position:0% +zero plug in zero for n that's equal to +B so B is zero that's + + align:start position:0% +B so B is zero that's + + + align:start position:0% +B so B is zero that's +nice + + align:start position:0% +nice + + + align:start position:0% +nice +e is zero and I plug in t here I get a t + + align:start position:0% +e is zero and I plug in t here I get a t + + + align:start position:0% +e is zero and I plug in t here I get a t +b is 0 minus + + align:start position:0% +b is 0 minus + + + align:start position:0% +b is 0 minus +t^2 so I solve for a here that means + + align:start position:0% +t^2 so I solve for a here that means + + + align:start position:0% +t^2 so I solve for a here that means +that a equals + + align:start position:0% +that a equals + + + align:start position:0% +that a equals +T A t^2 minus t^2 is z a has to be + + align:start position:0% +T A t^2 minus t^2 is z a has to be + + + align:start position:0% +T A t^2 minus t^2 is z a has to be +T so that means + + align:start position:0% +T so that means + + + align:start position:0% +T so that means +that en + + align:start position:0% +that en + + + align:start position:0% +that en +n is + + align:start position:0% +n is + + + align:start position:0% +n is +TN minus n^ + + align:start position:0% +TN minus n^ + + + align:start position:0% +TN minus n^ +2 now T is the number is the upper bound + + align:start position:0% +2 now T is the number is the upper bound + + + align:start position:0% +2 now T is the number is the upper bound +is just n plus + + align:start position:0% +is just n plus + + + align:start position:0% +is just n plus +m + + align:start position:0% +m + + + align:start position:0% +m +n + m * N - n^ 2 this gets really simple + + align:start position:0% +n + m * N - n^ 2 this gets really simple + + + align:start position:0% +n + m * N - n^ 2 this gets really simple +the n s cancels I just get n + + align:start position:0% +the n s cancels I just get n + + + align:start position:0% +the n s cancels I just get n +m that says if you're playing a fair + + align:start position:0% +m that says if you're playing a fair + + + align:start position:0% +m that says if you're playing a fair +game until you win M or lose n you + + align:start position:0% +game until you win M or lose n you + + + align:start position:0% +game until you win M or lose n you +expect to play for NM + + align:start position:0% +expect to play for NM + + + align:start position:0% +expect to play for NM +steps which is really nice this is p is + + align:start position:0% +steps which is really nice this is p is + + + align:start position:0% +steps which is really nice this is p is +a + + align:start position:0% +a + + + align:start position:0% +a +half very + + align:start position:0% +half very + + + align:start position:0% +half very +clean uh + + align:start position:0% +clean uh + + + align:start position:0% +clean uh +now if you let M be equal to Infinity + + align:start position:0% +now if you let M be equal to Infinity + + + align:start position:0% +now if you let M be equal to Infinity +you're going to expect to play + + align:start position:0% +you're going to expect to play + + + align:start position:0% +you're going to expect to play +forever so with a fair game if you play + + align:start position:0% +forever so with a fair game if you play + + + align:start position:0% +forever so with a fair game if you play +until you're broke the expected number + + align:start position:0% +until you're broke the expected number + + + align:start position:0% +until you're broke the expected number +of bets is + + align:start position:0% +of bets is + + + align:start position:0% +of bets is +infinite that's nice you just you you're + + align:start position:0% +infinite that's nice you just you you're + + + align:start position:0% +infinite that's nice you just you you're +you can play Forever is the + + align:start position:0% + + + + align:start position:0% + +expectation um + + align:start position:0% +expectation um + + + align:start position:0% +expectation um +now here's the weird thing if you expect + + align:start position:0% +now here's the weird thing if you expect + + + align:start position:0% +now here's the weird thing if you expect +to play Forever does that mean you're + + align:start position:0% +to play Forever does that mean you're + + + align:start position:0% +to play Forever does that mean you're +not likely to go home broke + + align:start position:0% + + + + align:start position:0% + +you expect to play for with you expect + + align:start position:0% +you expect to play for with you expect + + + align:start position:0% +you expect to play for with you expect +to play Forever and as long as you're + + align:start position:0% +to play Forever and as long as you're + + + align:start position:0% +to play Forever and as long as you're +playing you're not going home + + align:start position:0% +playing you're not going home + + + align:start position:0% +playing you're not going home +broke now you know there's some chance + + align:start position:0% +broke now you know there's some chance + + + align:start position:0% +broke now you know there's some chance +of going home broke because you might + + align:start position:0% +of going home broke because you might + + + align:start position:0% +of going home broke because you might +just lose every bet not + + align:start position:0% +just lose every bet not + + + align:start position:0% +just lose every bet not +likely all right + + align:start position:0% +likely all right + + + align:start position:0% +likely all right +um here's the weird thing the + + align:start position:0% +um here's the weird thing the + + + align:start position:0% +um here's the weird thing the +probability you go home broke if you + + align:start position:0% +probability you go home broke if you + + + align:start position:0% +probability you go home broke if you +play until you go broke is + + align:start position:0% +play until you go broke is + + + align:start position:0% +play until you go broke is +one you will go home broke it's just + + align:start position:0% +one you will go home broke it's just + + + align:start position:0% +one you will go home broke it's just +that it takes you expected infinite + + align:start position:0% +that it takes you expected infinite + + + align:start position:0% +that it takes you expected infinite +amount of time to do it sort of one of + + align:start position:0% +amount of time to do it sort of one of + + + align:start position:0% +amount of time to do it sort of one of +these weird things in a fair game so + + align:start position:0% +these weird things in a fair game so + + + align:start position:0% +these weird things in a fair game so +here we've got we prove that the + + align:start position:0% +here we've got we prove that the + + + align:start position:0% +here we've got we prove that the +expected number of bets is NM if M's + + align:start position:0% +expected number of bets is NM if M's + + + align:start position:0% +expected number of bets is NM if M's +infinite that becomes an imponent number + + align:start position:0% +infinite that becomes an imponent number + + + align:start position:0% +infinite that becomes an imponent number +of + + align:start position:0% +of + + + align:start position:0% +of +bets but one more theorem + + align:start position:0% +bets but one more theorem + + + align:start position:0% +bets but one more theorem +here this one's a little + + align:start position:0% + + + + align:start position:0% + +surprising this theorem is called quit + + align:start position:0% +surprising this theorem is called quit + + + align:start position:0% +surprising this theorem is called quit +while you were + + align:start position:0% +while you were + + + align:start position:0% +while you were +ahead + + align:start position:0% + + + + align:start position:0% + +if you + + align:start position:0% + + + + align:start position:0% + +start with + + align:start position:0% + + + + align:start position:0% + +nll and it's a fair + + align:start position:0% + + + + align:start position:0% + +game and you + + align:start position:0% + + + + align:start position:0% + +play until you go + + align:start position:0% +play until you go + + + align:start position:0% +play until you go +broke + + align:start position:0% + + + + align:start position:0% + +then the probability that you do go + + align:start position:0% +then the probability that you do go + + + align:start position:0% +then the probability that you do go +broke as opposed to playing forever is + + align:start position:0% +broke as opposed to playing forever is + + + align:start position:0% +broke as opposed to playing forever is +one it's a certainty you'll go broke + + align:start position:0% +one it's a certainty you'll go broke + + + align:start position:0% +one it's a certainty you'll go broke +even though it expects expect you expect + + align:start position:0% +even though it expects expect you expect + + + align:start position:0% +even though it expects expect you expect +to take it an infinite amount of time + + align:start position:0% +to take it an infinite amount of time + + + align:start position:0% +to take it an infinite amount of time +all right so let's prove + + align:start position:0% + + + + align:start position:0% + +that + + align:start position:0% + + + + align:start position:0% + +okay the proof is by + + align:start position:0% + + + + align:start position:0% + +contradiction assume it's not + + align:start position:0% +contradiction assume it's not + + + align:start position:0% +contradiction assume it's not +true and that means that you're + + align:start position:0% + + + + align:start position:0% + +assuming that there exists some number + + align:start position:0% +assuming that there exists some number + + + align:start position:0% +assuming that there exists some number +of dollars + + align:start position:0% +of dollars + + + align:start position:0% +of dollars +that you can start + + align:start position:0% +that you can start + + + align:start position:0% +that you can start +with and some Epsilon bigger than + + align:start position:0% +with and some Epsilon bigger than + + + align:start position:0% +with and some Epsilon bigger than +zero such + + align:start position:0% + + + + align:start position:0% + +that the + + align:start position:0% +that the + + + align:start position:0% +that the +probability that you lose the + + align:start position:0% +probability that you lose the + + + align:start position:0% +probability that you lose the +N which case you're going home + + align:start position:0% + + + + align:start position:0% + +broke let me yeah let me write it + + align:start position:0% +broke let me yeah let me write it + + + align:start position:0% +broke let me yeah let me write it +probability to go + + align:start position:0% + + + + align:start position:0% + +broke + + align:start position:0% +broke + + + align:start position:0% +broke +is at most one minus + + align:start position:0% +is at most one minus + + + align:start position:0% +is at most one minus +Epsilon in other words if the theorem is + + align:start position:0% +Epsilon in other words if the theorem is + + + align:start position:0% +Epsilon in other words if the theorem is +not true there exists some amount of + + align:start position:0% +not true there exists some amount of + + + align:start position:0% +not true there exists some amount of +money you can start with such that the + + align:start position:0% +money you can start with such that the + + + align:start position:0% +money you can start with such that the +chance you go broke is less than one + + align:start position:0% +chance you go broke is less than one + + + align:start position:0% +chance you go broke is less than one +less than one minus + + align:start position:0% + + + + align:start position:0% + +Epsilon okay now that means that for all + + align:start position:0% +Epsilon okay now that means that for all + + + align:start position:0% +Epsilon okay now that means that for all +M where you might possibly stop but + + align:start position:0% +M where you might possibly stop but + + + align:start position:0% +M where you might possibly stop but +you're not going to the probability you + + align:start position:0% +you're not going to the probability you + + + align:start position:0% +you're not going to the probability you +lose n before you win + + align:start position:0% + + + + align:start position:0% + +m is at most 1us + + align:start position:0% + + + + align:start position:0% + +Epsilon okay because we're saying the + + align:start position:0% +Epsilon okay because we're saying the + + + align:start position:0% +Epsilon okay because we're saying the +probability you lose n no matter what is + + align:start position:0% +probability you lose n no matter what is + + + align:start position:0% +probability you lose n no matter what is +at most at so it's certainly less than + + align:start position:0% +at most at so it's certainly less than + + + align:start position:0% +at most at so it's certainly less than +oneus Epsilon that you lose n before you + + align:start position:0% +oneus Epsilon that you lose n before you + + + align:start position:0% +oneus Epsilon that you lose n before you +win M + + align:start position:0% +win M + + + align:start position:0% +win M +doll and we know what that probability + + align:start position:0% +doll and we know what that probability + + + align:start position:0% +doll and we know what that probability +is this probability is just M over n + + align:start position:0% +is this probability is just M over n + + + align:start position:0% +is this probability is just M over n +plus M we proved that + + align:start position:0% +plus M we proved that + + + align:start position:0% +plus M we proved that +earlier so that has to be less than 1us + + align:start position:0% +earlier so that has to be less than 1us + + + align:start position:0% +earlier so that has to be less than 1us +Epsilon for all + + align:start position:0% +Epsilon for all + + + align:start position:0% +Epsilon for all +M and now I just multiply + + align:start position:0% +M and now I just multiply + + + align:start position:0% +M and now I just multiply +through for all + + align:start position:0% +through for all + + + align:start position:0% +through for all +M that means that m is less than or + + align:start position:0% +M that means that m is less than or + + + align:start position:0% +M that means that m is less than or +equal to 1us Epsilon n + + + align:start position:0% + + + + align:start position:0% + +m all right then we'll solve + + align:start position:0% +m all right then we'll solve + + + align:start position:0% +m all right then we'll solve +oops solve + + align:start position:0% + + + + align:start position:0% + +that + + align:start position:0% +that + + + align:start position:0% +that +okay so just multiply this out so for + + align:start position:0% +okay so just multiply this out so for + + + align:start position:0% +okay so just multiply this out so for +all + + align:start position:0% + + + + align:start position:0% + +M less than equal to n plus + + align:start position:0% + + + + align:start position:0% + +M um minus Epsilon M minus Epsilon M and + + align:start position:0% +M um minus Epsilon M minus Epsilon M and + + + align:start position:0% +M um minus Epsilon M minus Epsilon M and +now pull the M terms out + + align:start position:0% +now pull the M terms out + + + align:start position:0% +now pull the M terms out +here I get for all M Epsilon m is less + + align:start position:0% +here I get for all M Epsilon m is less + + + align:start position:0% +here I get for all M Epsilon m is less +than or equal to 1 - Epsilon + + align:start position:0% +than or equal to 1 - Epsilon + + + align:start position:0% +than or equal to 1 - Epsilon +n that means for all m m is smaller than + + align:start position:0% +n that means for all m m is smaller than + + + align:start position:0% +n that means for all m m is smaller than +1 - Epsilon Epsilon * + + align:start position:0% +1 - Epsilon Epsilon * + + + align:start position:0% +1 - Epsilon Epsilon * +n and that can't be true it's not true + + align:start position:0% +n and that can't be true it's not true + + + align:start position:0% +n and that can't be true it's not true +that for all M this is less than that + + align:start position:0% +that for all M this is less than that + + + align:start position:0% +that for all M this is less than that +because these are fixed + + align:start position:0% +because these are fixed + + + align:start position:0% +because these are fixed +values that's a + + align:start position:0% +values that's a + + + align:start position:0% +values that's a +contradiction all right so we've proved + + align:start position:0% +contradiction all right so we've proved + + + align:start position:0% +contradiction all right so we've proved +that if you keep playing until you're + + align:start position:0% +that if you keep playing until you're + + + align:start position:0% +that if you keep playing until you're +broke you will go broke with probability + + align:start position:0% +broke you will go broke with probability + + + align:start position:0% +broke you will go broke with probability +one so even if you're playing a fair + + align:start position:0% +one so even if you're playing a fair + + + align:start position:0% +one so even if you're playing a fair +game quit while you're ahead because if + + align:start position:0% +game quit while you're ahead because if + + + align:start position:0% +game quit while you're ahead because if +you don't you're going to go broke the + + align:start position:0% +you don't you're going to go broke the + + + align:start position:0% +you don't you're going to go broke the +swings will eventually catch up with you + + align:start position:0% +swings will eventually catch up with you + + + align:start position:0% +swings will eventually catch up with you +so if we draw the graph here see why + + align:start position:0% +so if we draw the graph here see why + + + align:start position:0% +so if we draw the graph here see why +that's + + align:start position:0% + + + + align:start position:0% + +true all right if I have time going this + + align:start position:0% +true all right if I have time going this + + + align:start position:0% +true all right if I have time going this +way + + align:start position:0% +way + + + align:start position:0% +way +all right and I start with n + + align:start position:0% + + + + align:start position:0% + +doll my Baseline is here the drift is + + align:start position:0% +doll my Baseline is here the drift is + + + align:start position:0% +doll my Baseline is here the drift is +zero I'm going to have + + align:start position:0% +zero I'm going to have + + + align:start position:0% +zero I'm going to have +swings I might have some really big high + + align:start position:0% +swings I might have some really big high + + + align:start position:0% +swings I might have some really big high +swings but it doesn't matter because + + align:start position:0% +swings but it doesn't matter because + + + align:start position:0% +swings but it doesn't matter because +eventually I'm going to get a really bad + + align:start position:0% +eventually I'm going to get a really bad + + + align:start position:0% +eventually I'm going to get a really bad +swing and I'm G to go + + align:start position:0% + + + + align:start position:0% + +broke okay now if you ever play a game + + align:start position:0% +broke okay now if you ever play a game + + + align:start position:0% +broke okay now if you ever play a game +where you're likely to be winning each + + align:start position:0% +where you're likely to be winning each + + + align:start position:0% +where you're likely to be winning each +time and the drift goes up + + align:start position:0% +time and the drift goes up + + + align:start position:0% +time and the drift goes up +that's a good game to play obviously it + + align:start position:0% +that's a good game to play obviously it + + + align:start position:0% +that's a good game to play obviously it +just keeps getting better and that's a + + align:start position:0% +just keeps getting better and that's a + + + align:start position:0% +just keeps getting better and that's a +whole math change + + align:start position:0% +whole math change + + + align:start position:0% +whole math change +there okay uh so that's it uh remember + + align:start position:0% +there okay uh so that's it uh remember + + + align:start position:0% +there okay uh so that's it uh remember +we have the ice cream study session + + align:start position:0% +we have the ice cream study session + + + align:start position:0% +we have the ice cream study session +Monday so come to that if you'd like uh + + align:start position:0% +Monday so come to that if you'd like uh + + + align:start position:0% +Monday so come to that if you'd like uh +and definitely come to the final on + + align:start position:0% +and definitely come to the final on + + + align:start position:0% +and definitely come to the final on +Tuesday and uh thanks for your hard work + + align:start position:0% +Tuesday and uh thanks for your hard work + + + align:start position:0% +Tuesday and uh thanks for your hard work +and being such a great class this + + align:start position:0% + + + + align:start position:0% + +year \ No newline at end of file diff --git a/5gI1aF81Saw.txt b/5gI1aF81Saw.txt new file mode 100644 index 0000000000000000000000000000000000000000..f80ca3675c5ff74e0985828cf373e405dfc5e66b --- /dev/null +++ b/5gI1aF81Saw.txt @@ -0,0 +1,347 @@ +Actually, the title is +interesting. + +It is Materials of Equilibrium. +A lot of people who look at the + +content would think of this as, +you know, this comes out of a + +course that used to be called +Thermodynamics of Materials + +which is a standard staple of +students who would do graduate + +materials education. +Almost everybody would have + +this as a requirement. +We deliberately changed the + +title to Materials of +Equilibrium to make it something + +broader. +We really wanted it to be + +Standard Classical +Thermodynamics, + +which is what we do, +but wanted to broaden that into + +sort of modern metrics to +understand and study the + +energetics of the materials. +What we do is we essentially + +teach, first of all, +we teach three large segments. + +One is classical +thermodynamics. + +And the idea is that people +need to see the general frame in + +which you can set up an energy +description for materials. + +How they react with their +environment. + +How they react with other +systems. + +So we wanted to teach them +first the general framework in + +which to study energetics of +materials. + +And the reason we want it that +general is because + +thermodynamics really has +evolved from being a science + +with a fixed application in +material science that would have + +been used for studying +metallurgy. + +You know, making steel, +refining of ores and things + +like that. +Very standard sort of + +application so that you could +almost teach through the + +applications. +Now thermodynamics has much + +more evolved to a much broader +range of applications and + +materials. +People use it on polymers. + +People use it on thin films. +People use it in biology. + +So we couldn't just teach +through applications anymore + +because there were too many. +And we don't know where it + +might go next. +So, because of that, + +I feel it real important to +teach the generic framework so + +that a student can go with this +and whatever they meet in their + +research apply it. +So that is about six weeks of + +lecturing. +After that, since + +thermodynamics is a macroscopic +description of materials, + +I would teach statistical +mechanics, which is the science + +that teaches you how to relate +microscopic details, + +atomic level details to the +thermodynamics. + +[UNINTELLIGIBLE PHRASE] +titanium and another aluminum. + +So that is the second piece. +And then the third piece is + +essentially taking all that and +making it more applied. + +So now we say we are going to +study solutions of materials. + +We are going to study thin +films of materials. + +We may study now polymer +mixtures. + +So those are the essential +three pieces. + +And so there is an enormous +emphasis on understanding the + +concepts behind what we teach. +Because of that, + +for example, +I do not assign homeworks on a + +weekly basis. +I feel that the time over which + +things have to sink in is longer +than a week in many cases. + +So we have sets of assignments +that go on the Web. + +Students do not have to turn +them in. + +A week later the solution is +gone so they can work on this at + +their own pace. +Well, the way we evaluate the + +students is in a very classical +sense. + +We have two mid-term exams. +The first one is purely on + +classical thermodynamics so it +would be the first block of the + +lecture, the course. +And there is a second mid-term + +which largely covers statistical +mechanics and some classical + +thermodynamics. +And then there is a + +comprehensive file. +And, actually, + +the comprehensive file is +weighted for half of the grade, + +so it is a very extensive +weighting. + +And, again, that comes back to +the idea that I feel, + +you know, this is a difficult +subject, thermodynamics, + +and students need sufficient +dwell time on it. + +So I feel that I can only +really evaluate them in the end + +whether they understand it. +If it were up to me, + +I would probably put even more +emphasis on the final. + +And so, the final is +comprehensive. + +It covers the whole course, +and also the integration + +between the different sections. +So 3.20 Energetics of Materials + +is a required course for all our +incoming DMSE students. + +So they would take it typically +in their first semester at MIT. + +It is a recommended course for +master students. + +Masters can also take a +shortened version of it. + +But typically what we see is +that most of the students in + +Material Science will take that +course in their first semester. + +And the reason it is taken in +the first semester is there are + +a lot of other classes that +build on it. + +You could see this course +really as the kind of basic + +description of how materials +evolve, what their equilibrium + +states are, how they interact +with their environment so other + +classes that talk about phase +transformations between + +materials or mechanical +behavior, the relation between + +mechanical properties and +processing would all build on + +this course. +It makes sense that it is + +taught early. +So the course has a thermal + +help email list which gets +logged now. + +That started, +we always had a thermal help + +email, and those emails would +get distributed to the staff in + +the class. +And whoever felt they could + +answer the question would pick +it up and cc everybody so we + +knew it was answered. +And then we had a creative TA + +who said, you know, +we have all these really + +interesting answers to questions +and we really should aggregate + +this. +And so, that is how the log got + +started. +And now you can actually look + +online and look at the questions +that were asked other years, + +the answers that were given. +And the students find that very + +useful. +Thermodynamics is a difficult + +subject. +It is one that is extremely + +difficult to learn in one +setting, you know, + +and in one pass through the +material. + +You know, it is not like taking +a course in PowerPoint or + +something where you learn facts. +Thermodynamics is more about + +assembling the facts in a +continuous framework. + +And it took me many years to do +that. + +So maybe my advice is to not +give up. + +It is a tough subject, +but it is one of these subjects + +that once you get it you wonder +why it was so hard. \ No newline at end of file diff --git a/5jrZ_AxAb5s.txt b/5jrZ_AxAb5s.txt new file mode 100644 index 0000000000000000000000000000000000000000..703ce70b791f5356f1d3d0878550a23562297dce --- /dev/null +++ b/5jrZ_AxAb5s.txt @@ -0,0 +1,259 @@ +align:start position:0% + +so in the end I would like to conclude + + align:start position:0% +so in the end I would like to conclude + + + align:start position:0% +so in the end I would like to conclude +it like this that there is a military + + align:start position:0% +it like this that there is a military + + + align:start position:0% +it like this that there is a military +there is no military solution to the + + align:start position:0% +there is no military solution to the + + + align:start position:0% +there is no military solution to the +terrorism however with a well thought + + align:start position:0% +terrorism however with a well thought + + + align:start position:0% +terrorism however with a well thought +out limited and accurately executed + + align:start position:0% +out limited and accurately executed + + + align:start position:0% +out limited and accurately executed +action could fulfill the short-term + + align:start position:0% +action could fulfill the short-term + + + align:start position:0% +action could fulfill the short-term +goals a more comprehensive and a policy + + align:start position:0% +goals a more comprehensive and a policy + + + align:start position:0% +goals a more comprehensive and a policy +oriented approach is essential to + + align:start position:0% +oriented approach is essential to + + + align:start position:0% +oriented approach is essential to +address this problem there's a need to + + align:start position:0% +address this problem there's a need to + + + align:start position:0% +address this problem there's a need to +understand why the public opinion in the + + align:start position:0% +understand why the public opinion in the + + + align:start position:0% +understand why the public opinion in the +Muslim countries is against United + + align:start position:0% +Muslim countries is against United + + + align:start position:0% +Muslim countries is against United +States it's important to note that + + align:start position:0% +States it's important to note that + + + align:start position:0% +States it's important to note that +majority of the people though they are + + align:start position:0% +majority of the people though they are + + + align:start position:0% +majority of the people though they are +not supportive of US policies but they + + align:start position:0% +not supportive of US policies but they + + + align:start position:0% +not supportive of US policies but they +are not for the terrorism so + + align:start position:0% +are not for the terrorism so + + + align:start position:0% +are not for the terrorism so +particularly in the Middle East their + + align:start position:0% +particularly in the Middle East their + + + align:start position:0% +particularly in the Middle East their +policy largely people criticize this + + align:start position:0% +policy largely people criticize this + + + align:start position:0% +policy largely people criticize this +policy but they are not supporting + + align:start position:0% +policy but they are not supporting + + + align:start position:0% +policy but they are not supporting +terrorist at large there are very few + + align:start position:0% +terrorist at large there are very few + + + align:start position:0% +terrorist at large there are very few +who support terrorism against us and + + align:start position:0% +who support terrorism against us and + + + align:start position:0% +who support terrorism against us and +another thing I would like to point out + + align:start position:0% +another thing I would like to point out + + + align:start position:0% +another thing I would like to point out +is that that it is certainly not the + + align:start position:0% +is that that it is certainly not the + + + align:start position:0% +is that that it is certainly not the +democracy and Freedom the people most of + + align:start position:0% +democracy and Freedom the people most of + + + align:start position:0% +democracy and Freedom the people most of +the people over here thinks that it's a + + align:start position:0% +the people over here thinks that it's a + + + align:start position:0% +the people over here thinks that it's a +democracy and freedom which they don't + + align:start position:0% +democracy and freedom which they don't + + + align:start position:0% +democracy and freedom which they don't +like about us it's certainly other + + align:start position:0% +like about us it's certainly other + + + align:start position:0% +like about us it's certainly other +things they are worried about and + + align:start position:0% +things they are worried about and + + + align:start position:0% +things they are worried about and +there's need to reach out to the public + + align:start position:0% +there's need to reach out to the public + + + align:start position:0% +there's need to reach out to the public +instead of just focusing on their rulers + + align:start position:0% +instead of just focusing on their rulers + + + align:start position:0% +instead of just focusing on their rulers +which are not Democratic set up so + + align:start position:0% +which are not Democratic set up so + + + align:start position:0% +which are not Democratic set up so +there's a difference between the rulers + + align:start position:0% +there's a difference between the rulers + + + align:start position:0% +there's a difference between the rulers +in the Muslim world and the General + + align:start position:0% +in the Muslim world and the General + + + align:start position:0% +in the Muslim world and the General +Public \ No newline at end of file diff --git a/5lO7gBJEzH4.txt b/5lO7gBJEzH4.txt new file mode 100644 index 0000000000000000000000000000000000000000..40386a54da7c67426e4c555ff0f59711fd7c6796 --- /dev/null +++ b/5lO7gBJEzH4.txt @@ -0,0 +1,4159 @@ +PROFESSOR: Today, we are +talking about the local behavior + +of a crease pattern. + +So you take some crease +pattern for some flat folding-- + +we're thinking about +flat foldability. + +This is a foldability question. + +I give you a crease +pattern like this. + +I want to know, does it fold +flat, like this one does. + +And we're studying +what happens locally + +right around a single vertex. + +So I didn't mention +graph terminology. + +It's probably useful +to mention that. + +These corners-- where all the +edges come together-- those + +are vertices. + +These triangles-- or in +general, some regions + +divided by the +creases-- we call faces. + +If we just sort of imagine +cutting a little disk + +around that vertex and +seeing how it behaves, + +we get a nice circular piece of +paper with some crease pattern. + +And we want to understand when +those things fold flat and when + +they don't. + +Sometimes they do, +sometimes they don't. + +This is kind of like a one +dimensional folding problem. + +So let me write some +stuff about that. + +So we get what we call single +vertex crease patterns. + +So something like-- +this is the example + +I have made-- just +something like that. + +That should be flat foldable. + +So we think of having +a disk of paper. + +It doesn't really +matter, but it's + +going to be easier +to reason about + +and think about a disk of paper. + +Really, we just mean some small +region around that vertex. + +There's obviously one vertex +in the crease pattern. + +Let's say we have n creases +emanating from one vertex. + +This pattern is +going to be defined + +by some sequence of angles. + +In general, theta +1 up to theta n. + +If there are n creases, there +will be n angles between them, + +say in clockwise order. + +And let's see. + +When we fold this thing +flat-- like in this picture-- + +we take this disk. + +We fold it along all +of those creases. + +What I'd like to +focus on is what + +happens to the +boundary of the paper. + +So there's this outer circle. + +The boundary is a circle. + +And locally, if you look +at one of these creases, + +it's like folding the +circle in half onto itself. + +And when you make all of these +creases, if you're successful, + +you end up folding the circle +onto a portion of the circle. + +So if you look at +this boundary-- which + +is a little hard to see. + +Why don't I trace it? + +It's going to do +something like this. + +So this is what the 3D +thing looks like blown up + +a little bit-- and I changed +the angles a little bit. + +But this is what a flat +folding would look like. + +And I'm really just +focusing on how + +the circle maps +around this circle. + +So a flat folding of a disk also +folds a circle onto a circle. + +So we have a flat folding on one +of these single vertex crease + +patterns, we get a folding +of a circle onto a circle. + +This is nice, because +circles are one dimensional. + +And last class, we talked about +folding one dimensional line + +segments. + +A circle is just a little +bit more complicated. + +It's different topology. + +But we can use a lot +of the same mindset, + +at least, as we did for folding +line segments onto the line. + +In particular, you can see, +yeah, this is kind of circular. + +But you could also imagine +unrolling it a little bit + +and making it straight. + +Something like this. + +So that it lies on +a straight line, + +if you just unroll that circle. + +So you also get a folding +of a circle in some sense + +onto a line by unrolling. + +Now, at this point, I want to +mention a slight issue here. + +I mean for this +unrolling to work-- + +if you're taking a circle +like this-- in particular, + +you must make at least one +fold for this to be possible. + +Because right now, if I +haven't folded anything, + +I just have a big circle, +I can't unroll circle + +onto a line. + +I haven't collapsed it. + +Yet here, I've made +it small enough + +that it only occupies a +portion of the entire circle. + +And so I can unroll it. + +So this is true, as long as +I make at least one fold. + +OK. + +Technically, I need to +assume another thing, which + +is that this thing came +from a flat piece of paper. + +I said there were these angles. + +And what I intended to mean is +that the sum of those angles + +is 360 degrees, as it is +in a flat piece of paper. + +But I'm not always going +to require this assumption. + +It's what we care +about for thinking + +about a crease pattern +of a flat piece of paper + +and we look at each vertex. + +This will be true. + +But when we reason about these +single vertex crease patterns, + +it's really useful to think +about, sort of in the middle, + +this could get smaller. + +So for example, you have +a pattern like this. + +Let's say I just take these +two creases on the bottom + +and I fold a crimp. + +Because I know a cramp is +kind of a good thing to do. + +So now I have what's +called a cone of paper. + +The sum of the angles-- +there's two angles here, + +this one and this one. + +Each one looks like +270-- no, not 270, 135? + +In total, it's 270. + +So the total angle there +is now less than 360. + +This is what we +call a convex cone. + +So if you relax this +constraint to allow less than + +or equal to 360, then +we get a convex cone. + +And today, I only want to talk +about flat paper and convex + +cones. + +We need this for the +induction, essentially-- + +for proving things +about the flat case. + +In the textbook-- if you look +at this chapter on single vertex + +crease patterns-- we +also prove or study + +the case where the sum of the +angles is greater than 360, + +which you could never +make from flat paper. + +But hey, it's fun +to think about. + +It's a natural generalization. + +And all the things +that we do here, + +you can generalize +to that situation. + +It's just a little bit harder. + +So what does it take to +fold a circle onto a line? + +In this situation +of a convex cone, + +where we make at least +one fold, our folding + +is going to lie along a +portion of the circle. + +We can unroll it +a little bit, get + +something lying on +a straight line. + +It's kind of like folding a line +segment onto a straight line, + +if it was flat folding of one +dimensional pieces of paper. + +But there's a lot +of differences. + +I mean, they are similar. + +But a lot of the things +we proved last time + +do not hold in the +case of circular paper. + +So I have a bunch of them here. + +So one problem-- you +may recall before, + +if we had a line segment and +we put an arbitrary crease + +pattern, then we could just +assign a mountain valley + +assignment, alternating +mountain valley. + +And that would always +fold flat, no collisions. + +OK. + +In this world of having a +circular piece of paper, + +that's no longer true. + +For example, if you have +this kind of crease pattern + +on a circle or in +the disk, it would + +look like this, +those two creases. + +You can't fold that thing flat. + +It's not going to work. + +We'll see exactly what +you need to forbid + +for that to make sense. + +Another example is +something like this. + +I mean, if I tried to draw this +in the line, what's happening + +is I have a short segment and +then I have a long segment. + +So the problem is +those ends don't meet. + +But even when the ends +meet-- like in this picture, + +imagine these are +vertically aligned-- + +if I do this alternating +mountain valley pattern-- + +mountain valley assignment-- +I can't join these ends + +and make a circle, because that +would collide with everything. + +So this thing actually +does have a flat folding + +starting from a circle. + +And I'm not going to try +to un-map it to a circle. + +It does fold, but not like that. + +Not with that alternating +mountain valley pattern. + +There are other annoying things. + +Let me tell you one +more on the proof side. + +Last time, we had +a lemma that said, + +if your crease +pattern is mingling-- + +which still is a +meaningful notion here-- + +then you have a crimp, or +an end fold in that case. + +Here, of course, we +don't have any end folds. + +Here, we also do not +get this implication. + +Mingling does not imply +the existence of a crimp. + +And where the proof breaks +down is if you have-- so + +if you remember, our +parentheses from last time-- + +we had this kind of pattern. + +And we said, well, you +keep going and either + +on the left side, you have +a beginning open paren + +or on the right side you have +a closing round parenthesis. + +In either case, you've +got an end fold. + +Now, this can actually +happen in a circle. + +And so you have +nothing you can do. + +So you could have this pattern. + +There would be no crimp. + +And probably, in that case, +you would not be flat foldable, + +but in particular, +this implication fails. + +So we have to do more work. + +But we're going to get +the same kind of result + +that, in linear +time, we can tell + +whether one of these +things folds flat. + +So that's good news. + +So last time, telling whether +a crease pattern folded flat + +was trivial. + +The answer was always yes. + +And now, it's not so trivial. + +So let's start +with characterizing + +crease patterns that fold flat. + +Then we will go to mountain +valley patterns that fold flat. + +It'd be great if I +could just say that, + +but I mean here, of +course, single vertex. + +So I give you one of +these sequence of angles. + +Let's say it sums +to 360 or less. + +When is it going to +be flat foldable? + +And the answer is very simple. + +Let me write it down. + +This thing is going to be +flat foldable if and only + +if the sum of the odd +angles is equal to the sum + +of the even angles. + +And, yeah, I'm implicitly +assuming and requiring + +here that n is even. + +That's something we'll prove. + +So n is actually even and +minus 1 is going be odd. + +And if you happen +to have started + +with a flat piece of paper-- +for the sum of all these things + +is 360-- then of course, if +you have them evenly divided, + +this sum will be 180 degrees. + +But if you started with the +convex cone, it'll be smaller. + +For this reason, a lot of +people-- or some people + +call this the 180 degree +property, or the pie property-- + +if you like to think in +radians instead of degrees. + +And we can do a +little example here. + +This guy-- this crease pattern-- +has a 90 degree angle here. + +And it has a 90 degree +angle down here. + +So the sum of those two is 180. + +Those are alternating angles, +different parity classes. + +This is 45. + +This is the complement, 135. + +And those also sum +to 180, of course. + +One does only if the other does. + +So it's flat foldable. + +We're golden. + +Something like this +is bad, because I + +mean it's an even number. + +But the odd angles do not equal +the sum of the even angles. + +One's clearly bigger. + +And this is a general property. + +This is also called +Kawasaki's theorem + +or Kawasaki-Justin's theorem. + +They proved it in 1989. + +This is pretty +much the beginning + +of origami mathematics. + +So let's prove it. + +There's two things to prove. + +One is that any flat +foldable crease pattern + +has this property, +which is pretty easy. + +And the other, which +is a little bit harder, + +is that if you +have this property, + +you really are flat foldable. + +That's the full +characterization. + +So let's start with +the easy direction. + +If you're flat foldable, +you must have that sum. + +OK. + +So it's all about thinking +what happens at a crease. + +So we're thinking +about the boundary + +of this piece of paper. + +We're thinking about the circle. + +And what's happening on +the circle as you travel, + +say counterclockwise +for some amount + +of time, that would +be first angle. + +Then you make a fold. + +It's either a +mountain or valley. + +At this point, we don't care. + +Either way, you turn around-- +maybe you turn around this way, + +or you turn around this way. + +But in terms as your +travel along a circle-- + +so we went theta 1 +counterclockwise. + +Now we're going to +go theta 2 clockwise; + +then we're going to go theta +3 counterclockwise, and so on. + +We keep alternating +back and forth. + +It's much easier to +think drawn a line. + +So we go to the right, theta 1. + +Then we go to the left, theta 2. + +Then we go to the +right, theta 3. + +And I don't know about +the layering here. + +I'm just drawing it in +terms of horizontal travel. + +The y-coordinate means nothing. + +In order for this thing +to be a flat folding-- + +to be a valid folding +of a circle of paper-- + +these guys have to have +the same x-coordinate. + +So I don't know-- I mean, +the y-coordinates, they also + +have to work out. + +But we're not thinking +about the y-coordinates. + +We're just thinking +about x travel. + +We've got to get +back to where we + +started if we're +folding a circle. + +That's it. + +So how much total travel +do we do, in a sign sense? + +How much do we go right? + +Well, we go theta +1 to the right. + +Then we go theta 2 +to the left, which + +is like going negative +theta 2 to the right. + +And then we go through +theta 3 to the right. + +Then we go negative +theta 4 to the right. + +And you add up this alternating +summation that must equal 0. + +The other thing that I should +say is that n has to be even. + +This is maybe obvious +at this point. + +But we're supposed to alternate. + +Every time we hit a crease, +we have to change direction. + +And so in the end, it's +important that after theta 4, + +we change direction +to visit theta 1. + +If they were aligned-- like +if theta 4 went over here + +and then theta 5 went +like that, and there + +was an odd number of +creases, this would be bad. + +Even though they're lined +up, there's no crease here. + +You just went straight +from theta 5 theta 1. + +You're supposed to change +direction every crease. + +So also, n is even to +alternate directions. + +Question? + +AUDIENCE: Oh, no. + +You already-- + +PROFESSOR: All right, good. + +Clear? + +This is pretty easy, once you +realize the angles correspond + +to x-coordinates in +this linear space. + +So why is this enough? + +In order to show +that this property is + +enough for flat +foldability, we need + +to actually worry about the +stacking order of these edges. + +We need to worry about +the y-coordinates. + +We need to make sure that +they can avoid collision + +with some mountain +valley assignment. + +The good news is we're free +to use whatever mountains + +and valleys we want. + +We can stack things +however we want. + +We just need to find +some valid state. + +And our intuition, from +the one dimensional case, + +was we should try alternating +mountains and valleys. + +That seemed like a good thing. + +It avoided collisions for +an open piece of paper-- + +for a line segment. + +Of course, we know +that's not enough. + +Here-- somewhere-- +I drew this example. + +So it's alternating +in the middle, + +and then that last +crease is a problem. + +But that's all we need to fix. + +It turns out it's not so hard. + +So we have a nice circle. + +What I'd like to do +is cut that circle. + +So here, I sort of cut +it and thought about it + +as a line segment and +then I wanted to rejoin. + +OK. + +I'm going to be careful +about where I cut it. + +OK, I want to cut at an +extreme left or extreme right. + +It doesn't matter. + +We can see here the cut +ended up being in the middle. + +That's bad. + +So how do I fix it? + +What does extreme mean? + +How do I tell-- +given a circle, it's + +a little hard to say +what extreme means, + +because it's circular. + +But if I take a +picture like this, + +I've already drawn it +with nice x-coordinates-- + +I don't know about the +y-coordinates yet-- I say, + +oh that's bad. + +My cut point ended +up being non-extreme. + +Well, this is extreme. + +So cut here instead. + +So what that means is +redraw this picture + +with this being the cut point. + +So maybe, this is the beginning. + +So we go like that again +and now we wrap around. + +So now we have this segment. + +And now we have this segment. + +And lo and behold, +it remained extreme. + +And this is always true. + +You can do this sort +of cut and rejoin + +the ends that were +messed up before. + +And you'll preserve +the x-coordinates. + +The x-coordinates +aren't changing + +when you do this kind +of transformation. + +So there's a clear leftmost +and there's a clear rightmost. + +You pick either one, +you cut there instead. + +And now we have +this nice property + +that it's easy to join +the ends, because it's + +as far left as you can go. + +There can't be anything +that penetrates, + +because that would +be farther left. + +Let me write down some +words corresponding to that. + +So once we cut at +this extreme crease, + +you can fold this +1D segment just + +like we used to be able to. + +So we can fold it flat +using the accordion fold, + +alternating mountain and valley. + +We know that works. + +And then all we need to show +is that the two ends can join. + +Those ends are the two +copies of the cut crease + +that we did in this first step. + +We need two things. + +One is that they are +aligned and that's + +where we need this condition-- +that the sum of the odd angles + +equals the sum of even angles, +which is the same as saying + +the alternating sum +is equal to zero. + +That tells us that +whatever we do, + +the x-coordinates are +lined up at the end. + +So they are aligned by the +assumption that we made here. + +And you can join +without crossing. + +So this is a statement +about y-coordinates. + +And we know it's OK, because +it's at the left extreme. + +So by this choice +of the proper cut, + +there could be other things +that come right to the boundary + +here, but that's considered OK. + +That's not crossing, +that just touching. + +Nothing can go farther +left because it + +was the left extreme. + +That's the end of the proof. + +Any questions about that? + +That's Kawasaki's +theorem-- Kawasaki-Justin. + +I would mention just for fun-- +this is sort of classic-- + +if you allow one of +these-- a non-convex cone, + +where you have more than +360 degrees of material-- + +this statement is not true. + +And there's one other +situation which can happen, + +which is that the alternating +sum of angles is not zero, + +but it's plus or minus +360 degrees, which is fun. + +And you can see examples +of that in the book. + +All right. + +So obviously, if +you want to tell + +whether a crease pattern-- or a +single vertex is flat foldable, + +you just compute this +thing in linear time + +and you know yes or no. + +So crease patterns +are pretty easy-- just + +have one extra condition. + +What about mountain +valley assignments? + +Last time, we looked at +mountain valley assignments + +and we showed that crimps +and end folds were always + +enough to fold any mountain +valley assignment that's + +out there. + +That will continue +to be true here, + +except now we don't +have end folds. + +Now, it's crimps all the way. + +What does it mean? + +So that is the flat foldable +mountain valley patterns. + +We're going to prove +that crimps are enough, + +but before we get +there, I need a bunch + +of sort of warm up facts about +valid mountain valley patterns. + +The first thing is just +counting mountains and valleys. + +So even if you play with a +simple example like this one, + +you see it as three +mountains and one valley + +or three valleys +and one mountain. + +In fact, if you have +a degree 4 vertex, + +with four creases +emanating from that point, + +those are your only choices. + +You could try, for example, +making it all valleys, + +and it-- I mean, +you can't do it. + +It's hard to demonstrate. + +You could try making it two +mountains and two valleys. + +Maybe I try to do +mountain mountain here + +and then somehow this is going +to be valley valley there. + +It's no good. + +But what's happening here is +that the number of mountains + +and the number valleys +must differ by exactly two. + +It doesn't matter who's bigger. + +So the difference could be +plus 2 or minus 2, because you + +can always flip over and negate +that difference, swapping + +mountains for valleys. + +But they always have to +differ by exactly two. + +Why is that? + +Well, this is-- +yeah, we're again + +going to think of a +picture like this. + +We have horizontal travel +according to the theta i's. + +We're also going to think +about the vertical picture. + +If this thing is flat +foldable-- so I'm assuming, + +it's flat foldable-- +then this must happen. + +This is called Maekawa's +theorem, by the way. + +It was proved by Jun Maekawa +in 1986-- a little earlier. + +Also proved by Jacques +Justin around the same time-- + +back before we were good at +internet and communication + +and whatnot. + +And there were little pockets +of mathematical origamists + +and they found each +other basically + +in '89, when there was the-- '89 +was the first origami science + +math and education +conference-- started + +bringing these people together. + +The last one was this summer. + +Right. + +So why is this true? + +I don't know. + +A flat folding looks +like something. + +It has no crossings. + +It has-- the horizontal +travel, we understand. + +It ends up back +where it started. + +There's also some notion of +layers and vertical travel, + +which is a little +tricky to think about. + +But the one thing that's +easy to think about-- I + +mean, this forms +essentially a polygon. + +It's like a really +squashed polygon. + +And these vertical segments are +actually really just points. + +OK, imagine. + +That's just where +you turn around. + +So it's like a polygon, +just stretched or squashed + +down onto a line. + +And we know some +things about polygons. + +OK, as an end +vertex polygon-- you + +know that the sum of +the interior angles + +is-- whatever it is. + +I always get confused +with that formula. + +So I don't like +to think about it. + +But one thing we-- an +easier way to think + +about that same statement +is just think about how much + +turning the polygon does. + +So you start here, you +turn right 180 degrees, + +you turn left 180 degrees, +you turn left 180, right 180, + +right 180, right 180. + +How much is it in total? + +Oh gosh, do I have to add? + +No. + +It's so simple. + +It's 360. + +Right? + +Just, if you think about +if you're going around + +in a circle, any polygon-- not +just flat-- but anything in two + +dimensions, the total amount +of turning you do is 360. + +Or if you count backwards, +it's negative 360. + +So this is the key-- +something you should all + +know about polygons. + +If you look at sum of the turn +angles-- how much turning you + +do at each vertex-- +that will always + +be plus or minus +360 in any polygon. + +This is equivalent to the sum +of the interior angles being, + +whatever, pi times n minus +2, which I don't remember. + +But this is much +easier to remember. + +And it's useful, because we +can map mountains and valleys + +to left and right turns. + +As I said, every time +this is a valley, + +it was a left turn by 180. + +Every time it was a mountain, +it was a right turn by 180. + +So valleys, mountains, +right turns-- + +so I'm going to think +of that as negative 180. + +Now, of course technically, it +could be the other way around. + +It could be this is +negative, this is positive. + +But I already have a +plus and minus here. + +So it's symmetric. + +So if we sum up the +turn angles-- which + +we know is supposed to +be plus or minus 360-- + +the sum of the turn angles +is going to be-- we're + +going to have 180 for +each valley, so 180 + +times the number of valleys. + +And we're going to have +negative 180 for each mountain. + +And so the 180's factor out. + +And this thing is supposed to +equal 360-- plus or minus 360. + +How could that be? + +Well, the number of valleys +minus number of mountains + +should be either 2-- for +plus 360-- or negative 2-- + +for minus 360. + +So that proves the theorem. + +And that's why, in a degree +4 vertex, one of them + +has to be 3, the +other one has to be 1. + +There's no other option, +because the total number is 4. + +It's the only way to +get the difference + +to be plus or minus 2. + +So that's kind of nice. + +But it's not enough, +unfortunately. + +If I gave you a mountain +valley pattern that + +satisfies this +condition, it still + +might not be flat foldable. + +That's maybe no surprise. + +It's not like we had +such a simple test + +for the one dimensional +case, which should be easier. + +We had to give an algorithm. + +We said repeatedly +crimp and end fold. + +If you get stuck, +the answer is no. + +If you don't get stuck, +you folded it great. + +I love this eraser-- +increases entropy. + +Let me tell you one case +that is easy to think about. + +Because it's nice. + +It reduces directly to +the one dimensional case. + +And that's what I +call the generic case. + +Generic is this very convenient +term we use in mathematics. + +It's actually really +tricky to define. + +So I'd like to not +define it, if I can. + +But maybe I should. + +The simple version, which +is not quite enough, + +is to say that all of the +angles in the crease pattern + +are different. + +OK, here, for example, +two of them are the same. + +There's two 90 degree angles. + +This is not generic. + +It's just easier to draw. + +But in general, I +mean, you imagine, + +you just draw some random thing. + +None of those lengths +are going to be the same. + +Yeah, the alternating +sum is zero. + +But that's it. + +And that's what I-- +the generic case + +is that is the only thing that +holds true about these angles. + +You can take the +alternating sum. + +That equals zero. + +If you take some alternating sum +of some subset of the angles, + +that will not equal zero. + +If you take a random example, +this is going to be true. + +OK, just bear with me. + +Suppose never any two +angles are the same. + +Then look at the +globally smallest crease, + +so globally smallest theta. + +Say it's theta i. + +So the picture is theta i, +theta i minus 1, theta i plus 1. + +And what do we know +if it's globally + +smallest and none of +the values are equal? + +Then we know that +these two are bigger. + +No big surprise. + +Think about what happens if +this is small, these are bigger, + +and you try to make these both +valleys or both mountains, + +that's, of course, bad. + +This is one of the +situations we had + +in the one dimensional case. + +I mean, really, +this is a circle, + +but I can think just locally +about what's happening here. + +So in this situation, one +of these must be a mountain + +and the other must be a valley. + +I don't know which +order they are, + +but I know they're different. + +And then I know I can +apply one of these crimps. + +Incidentally, the word crimp, +Jason Koo was asking about, + +like, why do you call +it crimp and not pleat? + +Probably, I should +call it pleat. + +But it's crimp in my mind. + +It's been crimp in +my mind since 1998 + +when we wrote the 1D paper. + +It was before I knew the word +pleat, so that's my excuse. + +So pleat or crimp, +take your pick. + +Crimp is usually +many pleats together. + +That's crimping. + +Cool. + +So crimps, we kind of like. + +Why do we like crimps? + +We proved, in the one +dimensional case last time, + +that if you make a crimp +and your original thing + +was flat foldable, the new +thing will be flat foldable. + +Good news is, that +is still true. + +I told you, all these +things were no longer + +true in the circular case. + +It's still true in +the circular case. + +Should I tell you-- + +Let me just remind you-- the +same proof works-- remind you + +what the proof looked like. + +We had a crimp, and we're +hoping to fold that first. + +We know at some point, +these creases get folded. + +But there may be +other junk in here, + +or maybe other junk in here. + +We'd like to get +rid of that junk. + +And so what we did +is move this junk up + +to here, which was always safe. + +We moved this junk down to here. + +And that was still a folded +state-- a flat folded state. + +OK, remember all this stuff. + +Therefore, we could have +folded the crimp first. + +And then we have a flat folding +in this situation, where + +this paper is effectively +glued together, which means, + +it was safe to fold this +crimp and glue these + +together and never +touch them again. + +So that is still true +in the circular case. + +That proof didn't really assume +anything about the paper. + +Would even work for +like tree shaped + +paper or something weird. + +So if we can find a crimp, which +we can in the generic case, + +then you just make a crimp, +make a crimp, repeat. + +If you ever get stuck, you know +that the original thing was not + +flat foldable, because the thing +you have is not flat foldable. + +Why? + +If there's no cramp +in the generic case, + +that means you have two valleys +around the smallest angle, + +and that's clearly bad. + +So-- I'm not writing +a lot of details here. + +Is that clear? + +If I have an angle +that's surrounded + +by strictly larger +angles, I know + +there must be one +mountain and one valley. + +Then I can safely make +a crimp and repeat. + +The trouble comes in when +these angles are equal. + +We never had to +think about angles + +being equal in the +one dimensional case. + +It didn't matter much. + +We just said, oh, you know, +it's safe to make a crimp, + +as long as this was greater +than or equal to this + +and this was greater +than or equal to this. + +That is still true; it's +safe to make a crimp. + +But how do we know +that there is a crimp? + +How do we know that there's a +mountain followed by valley? + +We don't. + +I mean, if they're equal, +this would be all right. + +That's two valleys is valid if +these three angles are equal. + +But I claim still somewhere +there's got to be a crimp. + +There's no longer a notion of +the globally smallest angle, + +because some of them are equal. + +We've got to find that +crimp, but it's out there. + +So we just need to +prove that it exists. + +So to do that, we're going +to generalize this theorem-- + +Meakawa-Justin-- that number +of mountains minus number + +of valleys is plus or minus 2. + +That's true, and +it's a statement + +about the sum of all the +angles-- all of the creases. + +What I'd like is something +a little bit more localized. + +And in particular, +we're going to think + +about when I have a whole +bunch of angles that are equal, + +how many mountains and +valleys can there be in there. + +So it's what I +call local counts. + +So while everything I said +so far is pretty classic, + +this result was proved +in 2001 by Tom Hall, + +so much more recent, +over a decade later. + +So let's think about +k equal angles. + +And I want that to be a maximal +sequence of equal angles, + +so the ones right after and +right before are different. + +And furthermore, +I'm going to assume + +that they're bigger-- +strictly larger angles. + +OK, so something like that. + +A bunch of equal +angles-- k of them-- + +bigger angles on either side. + +This almost always exists. + +I should mention-- so I'm +going to say something + +about this situation. + +But this situation should exist, +because I take the smallest + +angle out there and then +I see how many friends + +it has that are all equal. + +If it's the smallest angle-- +or it's one of the smallest + +angles-- then the +ones surrounding + +it are going to be bigger-- +unless all the angles are + +equal. + +So there's one case, which +we'll worry about later. + +It's very easy. + +All the angles are equal. + +In fact, I could tell you +how to worry about that. + +If all the angles are +equal, then everything + +is crimpable as long as we can +find a switch between mountain + +and valley-- somewhere. + +And because the number +of mountains and valleys + +is plus or minus 2, there's +got to be-- so they're almost + +in equal balance-- there's +got to be a valley. + +It can't be all valleys, +can't be all mountains. + +So somewhere, +there's a transition + +between mountain and valley. + +So you get a crimp out of that. + +But otherwise, if they're +not all equal-- let's + +think about k equal angles +surrounded by two larger guys. + +Forgot how technical this is. + +All right. + +Then I want to look at +the number of mountains + +and the number valleys among +these k plus one creases, + +so within that range. + +It's going to be 0, if k is odd. + +And it's going to be plus +or minus 1, if k is even. + +It's not plus or minus 2. + +Intuitively, plus or minus 2 is +when you go all the way around. + +Here, we're just +looking at a segment-- + +a portion of the entire circle. + +Remember, this is actually +a circle somewhere. + +And this corresponds +to, in the odd case, + +you're going to be going in +the same direction afterwards. + +In the even case, +you're going to have + +turned around but +not a full circle. + +So it's going to +be plus or minus 1. + +There's a lot of +ways to prove this. + +One way is to think +about convex cones. + +So if k is even, and you +fold this thing-- let's see, + +one, two, three, four, +five, six-- equal angles. + +And then there's +the two longer guys. + +They may not be the +same length, but that's + +what you get in the even case. + +So what I'd like to do is +just, in order to just reduce + +to things that we've already +thought about-- I mean, + +you could talk about +turn angles again, + +or you could just say, hey, +I know Maekawa's theorem. + +So as long as I could make +this into a circle, which + +I can do by adding +that stuff, now I + +have a nice circular-- +it's a flat folded state. + +There's no crossings +here, presumably + +because this did something. + +I don't actually know +that it's zigzagging. + +It might do other stuff. + +But it's not going to +cross what I just added. + +So the number of mountains +minus number of valleys, + +in total here, must +be plus or minus 2. + +I only added one +crease-- this one. + +So that's going to make +it either plus or minus 1 + +or plus or minus 3. + +If you think about +it a little bit, + +it has to be plus or minus 1. + +And hopefully, that's +what I wrote here, yes. + +Because I mean, really, we're +thinking about turn angles + +again, I'm afraid. + +Can't totally reduce it. + +We just turned around here. + +And we were about to +finish the circle, which + +would make it plus or minus 2. + +Before we finish the circle, +it's plus or minus 1. + +k is odd. + +Again, this might go +like that, whatever. + +But, because it's an +odd number, these guys + +are going in the same direction. + +And so the total turn +angle here must be 0. + +And one way to see that is to +extend it into a full polygon. + +You know that it's plus or +minus 2 for this whole thing. + +And I added two guys +in the same direction. + +If I remove them, it's going +to go down to plus or minus 0. + +That was a bit hand wavy. + +But do you buy that? + +AUDIENCE: [INAUDIBLE] +plus or minus 0? + +PROFESSOR: Plus or +minus 0 is 0, yeah. + +You went from 2 down +to zero, because you + +remove two identical guys. + +So let me tie this all +together, because there's + +so many little cases. + +So I want to know what +mountain valley patterns are + +flat foldable, single +vertex, m/v patterns. + +I claim there is a crimp. + +If it's flat foldable, +there has to be a crimp + +that you can find to do. + +Remember, a crimp +was where this length + +was less than or equal to +this length and less than + +or equal to this length. + +And one of these was m. + +One of them was v. That was +the definition of a crimp. + +I claim such a +thing always exists. + +The proof is two parts. + +If all the angles are equal, +we know that these conditions + +are always satisfied, +because everything is equal. + +So we just need to +find an m followed by v + +or a v followed by an m. + +And by Maekawa's theorem, we +know it's not all m's or all + +v's. + +So somewhere, there has to be +a transition from m to v's. + +So just use that lemma +theorem or the count property. + +Otherwise, if they're +not all equal, + +then I can apply this +local counts result, + +take the smallest angle-- take +one instance of the smallest + +angle. + +There could be many of them. + +Find all of its neighboring +friends that are equal. + +Then I know that the next +angles before and after + +have to be strictly bigger. + +Then I know that the number of +mountains and valleys in here-- + +if I look at the +difference and it's + +0, that means the +number of mountains + +equals the number of valleys. + +Therefore, there's +at least one of each. + +And therefore, there's a +transition from mountain + +to valley in there. + +Because the transition +from mountain to valley-- + +like right here, +that's a valid crimp. + +This guy's bigger; +this guy's equal. + +This would also be +a fine transition, + +because everybody's equal. + +This would also be +a fine transition. + +Any transition from +mountain to valley in here, + +I've got a crimp. + +The even case is a little-- I +got to think a little bit more. + +k is even. + +k plus 1, which is the number +of creases here, is odd. + +And the difference between +mountains and valleys + +among those k plus one +creases is plus or minus 1. + +Think about it for second. + +That means there's, again, at +least one mountain and at least + +one valley. + +Because k, to be even, +has to be at least 2. + +We've got to have at +least three things. + +So there's going to be at +least one of one and two + +of the other, in fact. + +And I just need one mountain and +one valley somewhere in there. + +And then I know there has to +be a transition from mountain + +to valley. + +Otherwise, use local counts. + +And in either case, we +get either a mountain + +to valley transition or a +valley to mountain transition. + +And I get it in such a way +that these inequalities + +on the lengths hold. + +So in other words, +that it's a crimp. + +Therefore, any flat foldable, +single vertex, mountain valley + +pattern has a crimp. + +Make it. + +And as I was arguing +here, just like last time, + +that crimp will still-- +after you do the crimp, + +you'll still be flat +foldable, so repeat. + +Cook until done is +how I like to put it. + +Question. + +AUDIENCE: What about the trivial +case of just folding a circle + +in half? + +PROFESSOR: The trivial case +of folding a circle in half. + +All right. + +That's a good question. + +It's kind of a technicality. + +One version would be to +say, that's zero vertices. + +That doesn't count. + +And we're thinking +about one vertex. + +And as soon as +you think about it + +as one vertex, which is +fine, then you actually + +have two creases there. + +So it's two creases. + +And hopefully, this works. + +Oh, I see what you're saying. + +It's not a crimp. + +That's a good point. + +AUDIENCE: But then +it's flat foldable. + +PROFESSOR: It is flat foldable, +and yet, there's no crimp. + +Damn it. + +All right. + +Sorry? + +AUDIENCE: But it follows +Maekawa's, right? + +PROFESSOR: Yeah. + +So I made a slight mistake here. + +I said if all the +angles are equal, + +then Maekawa says there's +at least one of each. + +That's not true when n equals 2. + +Then there's two of one +and zero of the other. + +As long as you have more than +two creases, then this is true. + +That's enough. + +So you have to handle +this as a special case. + +AUDIENCE: At the end +of your algorithm, + +you're always left +with two of the same-- + +PROFESSOR: That's true. + +This is an important +special case to remember, + +because this will be +the final picture. + +After you do a sequence of +crimps, this is the good case. + +If your thing is +flat foldable, you + +will always end up with that. + +AUDIENCE: That's a +case where everything + +is the same, smallest. + +PROFESSOR: It's another example +where all the angles are equal. + +So that's why this +is the situation. + +It's either Maekawa and +you get a cramp here, + +because n is greater than 2. + +And here, I should say, +if n is greater than 2, + +then this is true. + +Of course the n equals 2 +case, it looks like that. + +And it had better be both +valleys or both mountains. + +Otherwise, it's not going +to be flat foldable. + +I forgot about that. + +I should add it in the notes. + +But it's in the textbook, right. + +AUDIENCE: At the end +of the algorithm, + +it's not going to be a circle. + +It's going to be a cone. + +PROFESSOR: That's true. + +It won't actually +look like this. + +At the end of the algorithm, +it's going to be a cone. + +The two angles will be equal, +because of Kawasaki's theorem. + +And they should still be both +mountains or both valleys. + +But it's going to be-- +we can see it right here. + +So I apply my crimp, +and now I have a cone, + +and there's two angles. + +There's one here, which +has been fused together. + +And there's one here, +which is the original. + +They're equal. + +And it's two mountains +or two valleys, + +if I turned it upside down. + +And then it finishes. + +So that's the algorithm +in action-- two steps. + +First you find this crimp here. + +This is actually the +globally smallest angle. + +It's surrounded +by bigger angles. + +So it's really easy. + +Then I have a cone with +two equal angles, which + +is what has to +happen at the end. + +And then I'm done. + +Good? + +AUDIENCE: Is that the +only way to do it? + +PROFESSOR: This is +what always happens. + +Oh, is this the only way +to flat fold these things? + +No. + +There are other-- +yes, one of the two. + +I think it depends +what you're counting. + +If you're counting mountain +valley assignments-- I mean, + +if you just want to know, +can every mountain valley + +assignment be +folded by crimping. + +Then the answer is yes. + +That's what we proved. + +But if you want to get +every possible folded state, + +crimps are not +going to be enough. + +The reason they're not enough is +because we're using this thing. + +So, hey, here's some +hypothetical folded state. + +We can rip it out and make +the crimp has been done. + +But then there's a +folded state you're not + +able to reach by crimping. + +We need to work that into an +actual example, where crimping + +forbids you from reaching +some folded state. + +But I'm pretty sure one +exists because of this. + +AUDIENCE: Could that +be more like spirals? + +PROFESSOR: Yeah, maybe some +kind of spiraling thing. + +AUDIENCE: Well, layering +takes into account-- + +PROFESSOR: Right. + +What we're missing here is +getting all the possible layer + +stacking orders. + +So we're just trying to match +a mountain valley assignment. + +We're not going to match +a target layer ordering, + +because we simplified +the layer orders in order + +to make crimps possible. + +So crimps won't get you +some of the folded states. + +But one thing you can +play with over here-- + +that has been played +with by Tom Hall-- + +is if I give you +a crease pattern, + +how many flat foldable +mountain valley + +assignments does it have? + +OK, we have this nice linear +time algorithm to tell you + +whether a particular +one is doable. + +How many are there? + +And there is-- if +you work through all + +of the things I've shown you +in a little bit more detail, + +you can recover-- this +was finding a crimp. + +But you can actually +look at what + +are all the crimps +that are possible + +and actually count how +many different ways + +there are to fold. + +How many crimps you can do. + +And then given those +crimps, how many crimps you + +can go after that. + +And in the same linear +time kind of algorithm, + +you can figure out how many +different mountain valley + +patterns are flat foldable. + +That takes a little +bit more care. + +I will tell you the extremes. + +How small could the number of +flat foldable mountain valley + +assignments be for a +given crease pattern? + +Well, do you have +any guesses when? + +When do I have the least +choice of where to make crimps? + +Yeah. + +AUDIENCE: We have three angles. + +PROFESSOR: For general n. + +Sorry. + +But, yeah, three angles +or, I guess, two angles. + +We really can't do any-- +I don't have any choice. + +But for general n, +how should I disperse + +the theta i's in +order to make there + +be very few possible crimps? + +AUDIENCE: When there are +only two transitions. + +PROFESSOR: When there +are only two transitions + +between mountains and valleys. + +All the mountains are together. + +All the valleys are together. + +That's right, if I was asking +a question about mountains + +and valleys. + +But I was asking a +question about theta i's. + +So I want to count how many +mountain valley patterns there + +are-- mountain valley +assignments that + +are flat foldable for +a given crease pattern. + +AUDIENCE: So if you +have a bunch of angles, + +consecutive theta +i's are increasing? + +PROFESSOR: All the angles +are consecutive increasing. + +Yeah, that pretty much works. + +In fact, what I need +is the generic case, + +where all angles are +different and they never + +become equal by folding, +which is what generic means. + +So then there was only +really one crimp I could do, + +which is the globally +smallest angle. + +So actually, I still +have two choices. + +I could do mountain then +valley or valley then mountain. + +But I only have two +choices for that crimp. + +Then I will have two +choices for the next crimp, + +two choices for the next crimp. + +In general, I get 2 to the +n possible mountain valley + +assignments for +the generic case. + +OK, what about, +what's the opposite, + +where I get as much +choice as possible? + +AUDIENCE: Isn't 2 to the n every +mountain valley assignment? + +PROFESSOR: Yes, 2 to the +n-- no-- 2 to the n over 2. + +Thank you. + +Right. + +There are 2 to the n conceivable +mountain valley assignments. + +It can't be that big. + +Every time I do a crimp, I +eat two creases, not one. + +That's what I forgot. + +Good. + +It's still pretty big though. + +It's like square root of +all the possible things you + +could imagine are +indeed feasible. + +What, from 2 to the n +to 2 to the n over 2. + +When would I get the +most choice in crimping? + +AUDIENCE: All angles are equal. + +PROFESSOR: All angles are equal. + +That's the opposite extreme. + +And in this case-- +a little messier. + +When all the angles are +equal, the only property + +you need-- and you can +see that from the proof-- + +the only property you +need is that the number + +mountains minus +the number valleys + +is plus or minus +2, and n is even. + +As long as you have +that, we showed here, + +you're going to +have-- on alternation + +from mountain valley-- that's +a valid crimp, because all + +the angles are equal. + +And you keep going. + +So it's just, how do you +disperse that many-- how + +do I disperse n over +2 minus 1 mountains + +among n different positions. + +That's what this represents. + +And positions, how do I pick +n over 2 minus 1 of them + +to be mountains. + +Or it could be n over 2 +minus 1 of them are valleys. + +And that's this factor of 2. + +So it could have more +mountains or more valleys. + +And then you somehow +place those among those. + +And if you don't +know this notation, + +that's just what it means. + +If you want to know +using other notation, + +it's like this, n over +2 minus 1 factorial, + +over 2 plus 1 factorial. + +If you don't know factorials, +I'll tell you about them later. + +Cool. + +So that's kind of the end of +the single vertex situation. + +Yeah, I think I'll mention one +interesting open question here, + +which I would love to +explore maybe in our problem + +session-- which looks like it'll +be Mondays at 5:00, I think. + +This is one vertex, and we +went through all this work + +to solve a single +vertex situation. + +And it's interesting, +as we'll see, + +to think about locally +how each vertex behaves. + +But you would think, if +you have a crease pattern + +with two vertices, it +shouldn't be that much harder. + +So here we have linear time. + +How quickly can you tell +whether a two vertex crease + +pattern is flat foldable? + +As far as I know, no one +has looked at that problem. + +Surely, we can do +it in quadratic time + +but maybe even +linear time, I think. + +It can't be that hard, I think. + +In general, if I have a +small number of vertices-- + +say k vertices-- much +smaller than n creases, + +is there-- for the +algorithms people-- is there + +fixed parameter +tractable algorithm in k? + +Or can I get something-- +even getting something like n + +to some function of +k, would be progress. + +I think this should be doable. + +But ideally, we +get a running time + +that's exponential +in k and linear in n. + +That would be my hope. + +Why do I say it has +to be exponential? + +Because in general, +if I give you + +a crease pattern with n +vertices-- lots of vertices-- + +this problem is +NP-complete, which + +is-- there's not going +to be a polynomial time + +algorithm for it. + +Nothing good. + +We will prove that +next Wednesday. + +So I'll hold off on +that a little bit. + +But for two vertices, +how hard could it be? + +All right. + +I want to talk about +one related topic. + +And then we will go +to origami design + +and do a little bit +on the tree method. + +But before we get +there, I want to talk + +about local foldability, +which is a cool topic. + +People tend to forget about it. + +I really like it. + +I think it would make +a cool project also. + +It's a nice algorithm. + +It goes back to Bern +and Hayes, 1996. + +So it's also right +at the beginning + +of origami mathematics. + +And it's this idea, +all right, I give you + +a crease pattern now +arbitrarily many vertices. + +And if I ask you, +does it fold flat? + +That's NP-complete-- +intractable-- same paper. + +But what if I ask you just +to give me a mountain valley + +assignment that might fold flat? + +Well, that's also NP-complete. + +But if you actually +want it to fold flat, + +this is really the same problem. + +But if I ask you, give me a +mountain valley assignment, + +so that if I checked +every vertex according + +to this algorithm, at least +every vertex folds flat. + +That would seem nice. + +Definitely, I have to find a +mountain valley assignment that + +satisfies these +conditions, that as I + +do successive crimps, +every vertex-- if I cut out + +the vertex separately, +it would fold flat. + +This is the notion +of local foldability. + +And there's a linear +time algorithm + +to give you a mountain valley +assignment that ought to work, + +in that at each vertex it works. + +It still may not work globally +for some other reason. + +But it's pretty good. + +I think this would be, +actually, pretty practical. + +I think in a lot of real +world origami settings-- + +when you're doing +flat folding anyway-- + +locally foldable is going to be +enough to be globally foldable. + +That's a guess. + +I don't know if it's true. + +Consistent mountain +valley assignment, + +if there is one, so that each +vertex locally folds flat. + +Let me try to concoct a +small example that's relevant + +here-- got to think. + +Yes, I think that works. + +All right, here we go. + +I think this is in the textbook. + +I remember drawing it +in the past three years + +ago or whatever. + +So here's a crease pattern +on a square or whatever. + +AUDIENCE: The top +one should have-- + +PROFESSOR: Yes, it +should have this. + +Thank you. + +So this satisfies +Kawasaki's theorem-- + +that was the hard part-- +because these angles sum to 180. + +And it's symmetric all around. + +OK, these angles +are the smallest. + +They are 60 degrees. + +This is an equilateral triangle. + +So we have this-- not +quite the generic case, + +but we have the +smallest angle is + +surrounded by two larger angles. + +Therefore, one of +these is a mountain; + +the other is a valley. + +That means that +these two creases + +have to have different +assignments-- I'm + +going to write a not equal sign. + +One of these is a mountain, +and the other is a valley. + +They can't be the same. + +Also, these two +cannot be the same. + +Also, these two +cannot be the same. + +That's not possible. + +Because I've got three, +it has to alternate. + +You can alternate three times. + +You can only alternative +at even number of times. + +Two of these are mountains. + +One is valley. + +And then you've got a problem. + +OK, so this thing is +not flat foldable. + +And this algorithm +will tell you that. + +Because it will say, +hey, I can't even + +find a mountain +valley assignment + +that could possibly +fold each vertex flat. + +So this is a nice algorithm. + +At least, it will detect +annoying situations like that. + +So in order to solve +this, we're going to use-- + +and I'm just going to sketch +how this algorithm works-- + +we're going to use this +characterization and this idea + +that we can really find all +possible mountain valley + +assignments just by trying all +the possible crimp sequences. + +Now, there are +exponentially many. + +So it's not like I'm actually +going to try them all. + +But I need to explore that +space of candidate crimps + +and see what happens. + +So the idea is kind of crazy. + +The beginning of +the algorithm is + +fold each vertex flat-- somehow. + +I don't care how. + +Just pick a crimp, do it. + +Pick a crimp, do it-- +separately for each vertex. + +They're not going +to be compatible. + +And don't look at the mountain +valley assignment you get. + +But look at the crimping +sequence you get. + +So here, let's do +a little example-- + +a non-trivial example. + +So here, we have the peace sign, +and these two angles are equal. + +They're smallest. + +I could crimp this +angle first, or I + +could crimp this angle first. + +I have a choice. + +So I'll draw both of them. + +If I crimp this angle +first, I know these guys + +are paired up in the sense +that they must be not equal-- + +one's mountain and one's valley. + +After I do that crimp-- just +like in the real example + +I had-- this angle +will equal that angle. + +And these two guys must +have equal assignments. + +They must be both +mountain or both valley. + +In this situation, +these two guys + +are not equal, if I +crimp this pair first. + +And these two guys must +be equal-- equal now + +in the sense of being +mountain or valley. + +OK, so there are still +exponentially many + +possibilities in how to do this. + +But just pick one-- pick one +of these ways of pairing up. + +You're going to pair up +each of the n creases + +into n over 2 pairs. + +And they're going to have some +not equal and equal signs. + +So now, if you imagine +the general picture, + +like here, for example, I +might get-- in this pattern, + +I would be forced +to get not equals + +and these guys paired up. + +And in general, I want to +look at these kinds of cycles. + +If I come into a vertex-- +here's a vertex-- + +it's paired up with somebody. + +So if I come in here, +I can go out somewhere. + +And I come to this vertex, +it's paired with somebody. + +So I'm going to just-- I +can keep wandering around. + +And in general, there will +be a bunch of these paths + +that you can follow. + +What could the paths do? + +They either close up on +themselves-- maybe things + +are paired up in such a way +that you make a return trip. + +Or it could be some other path. + +Let me draw a dotted path. + +It could come in +here, and maybe it + +gets paired up with this guy. + +Maybe it goes off to infinity. + +It reaches the +boundary of the paper. + +Those are the two possibilities. + +You get paths, which +go off to the edge-- + +off to infinity on either end. + +Or you could get cycles. + +The cycles are the problem. + +Because whenever I have a cycle, +I have a parity constraint. + +For example, when +they're all not equals, + +the length of the +cycle must be even. + +If there were-- what's +the general statement? + +It's like the +parity of the cycle, + +which is whether +it's even or odd, + +should be equal to the parity of +the number of not equal signs. + +Something like that. + +I've got a sheet here. + +Great, I just said +"parity problems." + +It's something like that. + +It's either the +parity of the cycle + +should equal the parity +of the number of equals + +or the parity of the +number of not equals. + +I think, number of equals. + +Anyway, one of the two. + +And you can just check. + +I mean, you're forced. + +If I say, OK, let's +make this mountain, + +then this is either +equals or not equals. + +It'll tell me whether this +is mountain or valley. + +Just walk around the cycle. + +Either you get a +contradiction or you don't. + +If you get a contradiction, +we have a problem. + +How could we possibly +fix the problem? + +Well, when we made-- you +look at each of these cramps. + +I mean, in fact, you could +look at each of these vertices + +separately. + +But you think about one of +these crimps and say, well, + +could I have done +it another way? + +Sometimes, there are crimps +that have other equal choices. + +Maybe, there are a +bunch of equal angles. + +And I could have done +a different pairing. + +What happens when I try +a different pairing? + +Well, instead of this +being in one cycle + +and, let's say, this +being in another cycle, + +if I pair these guys +up instead, I'll + +end up merging those two +cycles into one bigger thing. + +It could be a path or a cycle. + +And the algorithm says, just +keep doing those cycle merges. + +And if you get stuck, your +thing is not locally foldable. + +That's the hard part to prove. + +Otherwise, you will find +one of these patterns + +that you can actually +resolve mountains and valleys + +all the way through. + +So let's say, so start with some +folding-- say local folding, + +whatever. + +I'm going to say with some +pairing of creases at vertices. + +And merge two paths or +cycles whenever possible. + +And when I say merge, +I mean whenever + +you have-- what are the possible +things you could possibly + +merge-- when you have at some +point during the algorithm + +a bunch of equal angles, you +have a choice which of these + +you crimp. + +Obviously, the mountain valley +assignment is not fixed. + +You can crimp any of them. + +You picked one of +them, and it's sort + +of merging whatever this +thing is attached to, + +to whatever this +thing is attached to. + +If there's something else that's +disconnected from that thing, + +I want you to instead +merge two of them that + +combines two different +connected components-- two + +paths or cycles. + +Merging means I decrease +the total number + +of paths or cycles. + +I combine two into one. + +Whenever that's possible, do it. + +You can prove that +if you have parity + +problem in the +merge thing, you had + +to have had a parity +problem originally. + +And merging can only +fix parity problems. + +That's the claim, and that's +what I will not prove. + +Once you know that-- and it +doesn't matter in what order + +or how you choose to merge-- you +just merge as much as possible. + +And either the resulting +thing is OK or not. + +And accordingly, you will +tell whether this thing + +is locally foldable. + +Sorry, I want to move +on to other things. + +But I think this would be a fun +thing to actually implement. + +It's an easy algorithm. + +And it's, I think, a pretty good +test it for problems like this + +that prevent flat foldability. + +So let's move on from +foldability to origami design. + +So a bit of a big transition. + +And we're going to talk +about origami design + +a lot more next class also +but just start it off today. + +And the particular +algorithm for origami design + +I want to talk about is +called the tree method. + +This is probably +the oldest algorithm + +for origami design, +in that people + +have been thinking about it and +developing it for many years + +through this period called +the Bug Wars, when people were + +trying to design more and +more complicated insects. + +It's like, well, I can make +an insect with six legs. + +Oh yeah, well I can make +a spider with eight legs. + +Oh yeah, well I can make +an insect-- a beetle that + +has wings and horns and there's +thorns on the horns-- you know, + +all these crazy things. + +During that time, +there were a lot + +of people thinking +about how do I + +make more and more +complicated-- especially, more + +limbs in my creatures +and very precise + +arrangements of those +limbs, let's say. + +And that is what the tree +method deals with and was really + +formalized by Robert Lang, +who published a paper in '96, + +describing it as a sort +of complete algorithm. + +And it's still +not known for sure + +that that algorithm +always works. + +But that's what +we've been working + +on-- me and Marty and Rob Lang-- +for the last four years or so. + +And soon, we will +publish that thing + +and prove that this +thing always works. + +But I'm going to describe the +algorithm without the proof + +that it works. + +And what it does-- +I'll tell you its goal + +from a mathematical perspective. + +So it's interested in +practical origami design. + +So we're going to start from +a square piece of paper. + +It would also work +for triangular pieces + +of paper or anything convex. + +But squares are what +people usually care about. + +Sometimes it's used +for rectangles also. + +The idea is I give to +you a stick figure. + +So that's formally, +it's a tree-- + +a graph without any cycles. + +It's a metric tree, meaning +that I put lengths on the edges. + +I know this length-- this +edge length-- is maybe + +twice as long as this one. + +So I really draw it with +edge lengths in mind. + +Then what I want +you to do is find + +some folding of a +piece of paper-- + +I should really be looking +at what I'm trying to match. + +So here, here, this +goes down, such + +that I want to find some folding +of a square paper-- in fact, + +the smallest square +possible, so that when + +I project-- like +this-- vertically, + +the projection of that folding +is exactly that metric tree. + +And this is called a +uniaxial-- this thing is + +called a uniaxial base. + +Let me tell you a little bit +why it's called a uniaxial base. + +We're thinking about what +are called origami bases. + +These there like the +beginning of origami models. + +And most classic +origami models-- + +like more than 60 years ago-- +start from one of these bases. + +You've got waterbomb base on +the top left, preliminary base, + +fish base, bird base +windmill base, and frog base. + +I can't remember them all. + +I have a little example here. + +This is the waterbomb base. + +So it's just very +simple crease pattern. + +And why this is useful +is, it gives you + +sort of four flaps of +paper to work with. + +Maybe you make one +of them the head + +and the other two wings +and the back one a tail, + +if you're making a crane. + +If doesn't actually +start not from this space + +but from the other one. + +But the same idea. + +If you're folding a +crane, one of these + +would be the head, the +other tail, and two wings. + +This is great if you're +making a four flap animal. + +And if you think +about its projection-- + +and it's easier to think +about in this other picture-- + +the projection of this +thing is a four limbed star. + +You can see it's a plus sign. + +All of them are the same length. + +And so this is +actually something + +you can get out of +the tree method. + +You just give that +as your input. + +You will get this 3D thing +and this crease pattern + +as your origami-- as the output. + +Let me show you the +program in action. + +So Robert Lang +implemented this thing. + +It's called tree maker. + +It's freely available, open +source, all that good stuff. + +And I'm not an expert at +using it, so bear with me. + +But if we wanted to say, +I would like that star. + +OK, now, I drew it obviously +not with all the lengths equal, + +but it's ignoring the +lengths that I drew. + +And they're actually +specified here. + +So all the lengths here +are supposed to be 1. + +And then I say, OK, optimize. + +And then make a crease pattern. + +And then show me +the crease pattern. + +And there it is, exactly +the crease pattern + +I made, although actually I can +see from the mountain valley + +assignment-- because +this is not really-- + +this is not flat origami. + +It made it this way. + +So it's flat. + +Of course, the projection is +the same-- still four limbs. + +And so it's dashes for valleys +and solid lines for mountains. + +But you can make +anything you want. + +So let's say we want to +make-- I don't know-- a lizard + +or something. + +So the blue lines are the tree. + +So here's-- can I do this? + +Yes, there we go. + +So here, I have a forearm, +a head, a foreleg, + +another forearm, a body segment, +tail, and two hind legs. + +Maybe I want to make that. + +So I say optimize and then +make a crease pattern, and then + +boom. + +You fold that, and it will +have exactly that projection. + +And assuming it did a +reasonable job at computation, + +this will be the best +way to fold this thing. + +And it's the +smallest square that + +matches exactly that shape. + +You get the best scale +factor between the size + +of your piece of paper +and the target shape. + +But actually, doing +that optimization-- + +the first step I +did-- is NP-complete. + +So it's not going +to do it perfectly, + +and we'll prove that Wednesday. + +But the heuristics +are pretty good. + +AUDIENCE: It finds a local. + +PROFESSOR: It finds +a local minimum, + +and often it finds +a pretty good one. + +And sometimes you can coax it +to find better ones, but, yeah. + +It's not perfect, but +hey, it's NP-complete. + +So you can't do it. + +This actually shows you what it +would look like in x-ray view. + +And then you can say, +oh, that was nice, + +but let's-- where is +my-- yeah, that was good. + +But maybe I really +wanted the head segment + +to be shorter length of 0.5. + +And then I wanted the +tail to be really long. + +And then you can optimize that +and find a crease pattern. + +And it'll complain. + +Because it's having trouble. + +Oh, dear. + +Demo effect. + +I should have tried +this example before. + +It's not-- oh, gosh. + +It's one of these annoying ones. + +I should say-- I should add +some feature like maybe a strain + +split something, add a +little bit, maybe do that + +and-- there we go. + +I cheated, and I'll explain +how I cheated last time. + +But if sometimes the +particular method + +fails but you can fix it by +adding in another tiny limb + +off the edge somewhere-- +and of course, you + +can then get rid of that at +the end when you're folding, + +it only makes the +problem slightly harder. + +And it'll still find a folding. + +But we'll talk about +that next time. + +And I'm way out of time, +so we will stop there. \ No newline at end of file diff --git a/5uygC4oJvCI.txt b/5uygC4oJvCI.txt new file mode 100644 index 0000000000000000000000000000000000000000..d018c0ee6f3a8ff2ff6bce1faf224255c584ef76 --- /dev/null +++ b/5uygC4oJvCI.txt @@ -0,0 +1,9667 @@ +align:start position:0% + +so so um so remember what has been + + align:start position:0% +so so um so remember what has been + + + align:start position:0% +so so um so remember what has been +happening to the US economy as as as + + align:start position:0% +happening to the US economy as as as + + + align:start position:0% +happening to the US economy as as as +economy and and it happens similarly + + align:start position:0% +economy and and it happens similarly + + + align:start position:0% +economy and and it happens similarly +with a few lcks and leads and and + + align:start position:0% +with a few lcks and leads and and + + + align:start position:0% +with a few lcks and leads and and +differences in sizes but around the + + align:start position:0% +differences in sizes but around the + + + align:start position:0% +differences in sizes but around the +world in most economies around the world + + align:start position:0% +world in most economies around the world + + + align:start position:0% +world in most economies around the world +as the economy began to reopen from + + align:start position:0% +as the economy began to reopen from + + + align:start position:0% +as the economy began to reopen from +covid H we had a situation where we had + + align:start position:0% +covid H we had a situation where we had + + + align:start position:0% +covid H we had a situation where we had +sort of too much demand for Supply the + + align:start position:0% +sort of too much demand for Supply the + + + align:start position:0% +sort of too much demand for Supply the +the potential output using the + + align:start position:0% +the potential output using the + + + align:start position:0% +the potential output using the +terminology you'll have in the ISL NPC + + align:start position:0% +terminology you'll have in the ISL NPC + + + align:start position:0% +terminology you'll have in the ISL NPC +model was slow in picking up because we + + align:start position:0% +model was slow in picking up because we + + + align:start position:0% +model was slow in picking up because we +still had lots of bottlenecks in the + + align:start position:0% +still had lots of bottlenecks in the + + + align:start position:0% +still had lots of bottlenecks in the +supply chains and and in different + + align:start position:0% +supply chains and and in different + + + align:start position:0% +supply chains and and in different +sectors of the economy H some people + + align:start position:0% +sectors of the economy H some people + + + align:start position:0% +sectors of the economy H some people +didn't didn't want to come back to work + + align:start position:0% +didn't didn't want to come back to work + + + align:start position:0% +didn't didn't want to come back to work +to the labor force for a while and and + + align:start position:0% +to the labor force for a while and and + + + align:start position:0% +to the labor force for a while and and +and so on so so the supply side was very + + align:start position:0% +and so on so so the supply side was very + + + align:start position:0% +and so on so so the supply side was very +still + + align:start position:0% +still + + + align:start position:0% +still +impair ER not as impair as in the middle + + align:start position:0% +impair ER not as impair as in the middle + + + align:start position:0% +impair ER not as impair as in the middle +of the covid in 2020 say but it's still + + align:start position:0% +of the covid in 2020 say but it's still + + + align:start position:0% +of the covid in 2020 say but it's still +in pair while + + align:start position:0% +in pair while + + + align:start position:0% +in pair while +demand was very strong because people + + align:start position:0% +demand was very strong because people + + + align:start position:0% +demand was very strong because people +were fed up of being staying at home + + align:start position:0% +were fed up of being staying at home + + + align:start position:0% +were fed up of being staying at home +they had saved a lot during the the + + align:start position:0% +they had saved a lot during the the + + + align:start position:0% +they had saved a lot during the the +covid recession and they wanted to spend + + align:start position:0% +covid recession and they wanted to spend + + + align:start position:0% +covid recession and they wanted to spend +okay and there had been lots of fiscal + + align:start position:0% +okay and there had been lots of fiscal + + + align:start position:0% +okay and there had been lots of fiscal +support and monetary policy support and + + align:start position:0% +support and monetary policy support and + + + align:start position:0% +support and monetary policy support and +so on so people feel wealthy and felt + + align:start position:0% +so on so people feel wealthy and felt + + + align:start position:0% +so on so people feel wealthy and felt +rich + + align:start position:0% +rich + + + align:start position:0% +rich +and and so they want to spend you know + + align:start position:0% +and and so they want to spend you know + + + align:start position:0% +and and so they want to spend you know +if is there's a big demand but Supply is + + align:start position:0% +if is there's a big demand but Supply is + + + align:start position:0% +if is there's a big demand but Supply is +not there that is starts introducing + + align:start position:0% +not there that is starts introducing + + + align:start position:0% +not there that is starts introducing +inflationary pressures that's say we + + align:start position:0% +inflationary pressures that's say we + + + align:start position:0% +inflationary pressures that's say we +have a a negative output a positive + + align:start position:0% +have a a negative output a positive + + + align:start position:0% +have a a negative output a positive +output Gap output above potential output + + align:start position:0% +output Gap output above potential output + + + align:start position:0% +output Gap output above potential output +that puts immediately inflationary + + align:start position:0% +that puts immediately inflationary + + + align:start position:0% +that puts immediately inflationary +pressure that's what we learn from the + + align:start position:0% +pressure that's what we learn from the + + + align:start position:0% +pressure that's what we learn from the +Philips curve and all that + + align:start position:0% +Philips curve and all that + + + align:start position:0% +Philips curve and all that +okay and now for a while the the the FED + + align:start position:0% +okay and now for a while the the the FED + + + align:start position:0% +okay and now for a while the the the FED +um did not want to react to this because + + align:start position:0% +um did not want to react to this because + + + align:start position:0% +um did not want to react to this because +they thought that this was going to be + + align:start position:0% +they thought that this was going to be + + + align:start position:0% +they thought that this was going to be +mostly a temporary phenomenon that + + align:start position:0% +mostly a temporary phenomenon that + + + align:start position:0% +mostly a temporary phenomenon that +Supply would recover pretty rapidly and + + align:start position:0% +Supply would recover pretty rapidly and + + + align:start position:0% +Supply would recover pretty rapidly and +that you know people would after taking + + align:start position:0% +that you know people would after taking + + + align:start position:0% +that you know people would after taking +one trip well they wouldn't want to take + + align:start position:0% +one trip well they wouldn't want to take + + + align:start position:0% +one trip well they wouldn't want to take +a second one fiscal support was winding + + align:start position:0% +a second one fiscal support was winding + + + align:start position:0% +a second one fiscal support was winding +down and so on so they thought this + + align:start position:0% +down and so on so they thought this + + + align:start position:0% +down and so on so they thought this +would go away and they didn't want to + + align:start position:0% +would go away and they didn't want to + + + align:start position:0% +would go away and they didn't want to +sort of cool off the economy because + + align:start position:0% +sort of cool off the economy because + + + align:start position:0% +sort of cool off the economy because +they thought they didn't want to fight a + + align:start position:0% +they thought they didn't want to fight a + + + align:start position:0% +they thought they didn't want to fight a +temporary fight now as a result of new + + align:start position:0% +temporary fight now as a result of new + + + align:start position:0% +temporary fight now as a result of new +shocks the war and things like that but + + align:start position:0% +shocks the war and things like that but + + + align:start position:0% +shocks the war and things like that but +also that the initial call was not right + + align:start position:0% +also that the initial call was not right + + + align:start position:0% +also that the initial call was not right +was incorrect that there was a lot of + + align:start position:0% +was incorrect that there was a lot of + + + align:start position:0% +was incorrect that there was a lot of +inertia in demand and and and and that + + align:start position:0% +inertia in demand and and and and that + + + align:start position:0% +inertia in demand and and and and that +that pickup in demand sort of lasted a + + align:start position:0% +that pickup in demand sort of lasted a + + + align:start position:0% +that pickup in demand sort of lasted a +lot longer than I expected H is that + + align:start position:0% +lot longer than I expected H is that + + + align:start position:0% +lot longer than I expected H is that +that inflation really began to rise and + + align:start position:0% +that inflation really began to rise and + + + align:start position:0% +that inflation really began to rise and +the Fed was really CAU what is called + + align:start position:0% +the Fed was really CAU what is called + + + align:start position:0% +the Fed was really CAU what is called +behind the curve know they needed to + + align:start position:0% +behind the curve know they needed to + + + align:start position:0% +behind the curve know they needed to +they were they should have started at + + align:start position:0% +they were they should have started at + + + align:start position:0% +they were they should have started at +least Expos it's easy to see it that way + + align:start position:0% +least Expos it's easy to see it that way + + + align:start position:0% +least Expos it's easy to see it that way +they should have remember what you have + + align:start position:0% +they should have remember what you have + + + align:start position:0% +they should have remember what you have +if you have an a situation where output + + align:start position:0% +if you have an a situation where output + + + align:start position:0% +if you have an a situation where output +is above potential output the interest + + align:start position:0% +is above potential output the interest + + + align:start position:0% +is above potential output the interest +rate is supposed to be rising so the FED + + align:start position:0% +rate is supposed to be rising so the FED + + + align:start position:0% +rate is supposed to be rising so the FED +is supposed to be increasing the + + align:start position:0% +is supposed to be increasing the + + + align:start position:0% +is supposed to be increasing the +interest rate but it didn't for a while + + align:start position:0% +interest rate but it didn't for a while + + + align:start position:0% +interest rate but it didn't for a while +assuming that the forces that were + + align:start position:0% +assuming that the forces that were + + + align:start position:0% +assuming that the forces that were +bringing potential output down and + + align:start position:0% +bringing potential output down and + + + align:start position:0% +bringing potential output down and +demand up were so transitory when they + + align:start position:0% +demand up were so transitory when they + + + align:start position:0% +demand up were so transitory when they +discovered that wasn't the case they had + + align:start position:0% +discovered that wasn't the case they had + + + align:start position:0% +discovered that wasn't the case they had +to start catching up as a result of that + + align:start position:0% +to start catching up as a result of that + + + align:start position:0% +to start catching up as a result of that +they began to hike interest very very + + align:start position:0% +they began to hike interest very very + + + align:start position:0% +they began to hike interest very very +rapidly okay and the unusually rapidly + + align:start position:0% +rapidly okay and the unusually rapidly + + + align:start position:0% +rapidly okay and the unusually rapidly +for economy like the US and the reason + + align:start position:0% +for economy like the US and the reason + + + align:start position:0% +for economy like the US and the reason +there are many reasons why why policy + + align:start position:0% +there are many reasons why why policy + + + align:start position:0% +there are many reasons why why policy +makers especially monetary policy makers + + align:start position:0% +makers especially monetary policy makers + + + align:start position:0% +makers especially monetary policy makers +prefer to be gradualist meaning to move + + align:start position:0% +prefer to be gradualist meaning to move + + + align:start position:0% +prefer to be gradualist meaning to move +things in smaller steps rather than in + + align:start position:0% +things in smaller steps rather than in + + + align:start position:0% +things in smaller steps rather than in +one big Bank ER especially in the way up + + align:start position:0% +one big Bank ER especially in the way up + + + align:start position:0% +one big Bank ER especially in the way up +no if if it is to cut rates they're very + + align:start position:0% +no if if it is to cut rates they're very + + + align:start position:0% +no if if it is to cut rates they're very +willing to be very aggressive in cutting + + align:start position:0% +willing to be very aggressive in cutting + + + align:start position:0% +willing to be very aggressive in cutting +rates but racing rates is something they + + align:start position:0% +rates but racing rates is something they + + + align:start position:0% +rates but racing rates is something they +tend to be reluctant to do very very + + align:start position:0% +tend to be reluctant to do very very + + + align:start position:0% +tend to be reluctant to do very very +rapidly and one of the main reasons + + align:start position:0% +rapidly and one of the main reasons + + + align:start position:0% +rapidly and one of the main reasons +they're reluctant to do that very + + align:start position:0% +they're reluctant to do that very + + + align:start position:0% +they're reluctant to do that very +rapidly is because something may break + + align:start position:0% +rapidly is because something may break + + + align:start position:0% +rapidly is because something may break +in the process and there are certain + + align:start position:0% +in the process and there are certain + + + align:start position:0% +in the process and there are certain +things are very important if they break + + align:start position:0% +things are very important if they break + + + align:start position:0% +things are very important if they break +there are certain other things are not + + align:start position:0% +there are certain other things are not + + + align:start position:0% +there are certain other things are not +very important if they break but one of + + align:start position:0% +very important if they break but one of + + + align:start position:0% +very important if they break but one of +the things that is very important if + + align:start position:0% +the things that is very important if + + + align:start position:0% +the things that is very important if +they break is Banks okay and and and + + align:start position:0% +they break is Banks okay and and and + + + align:start position:0% +they break is Banks okay and and and +that's typically where you get run into + + align:start position:0% +that's typically where you get run into + + + align:start position:0% +that's typically where you get run into +trouble when there is episodes of very + + align:start position:0% +trouble when there is episodes of very + + + align:start position:0% +trouble when there is episodes of very +fast hikes in rates now because the US + + align:start position:0% +fast hikes in rates now because the US + + + align:start position:0% +fast hikes in rates now because the US +banking sector especially the large + + align:start position:0% +banking sector especially the large + + + align:start position:0% +banking sector especially the large +Banks were sort of very resilient they + + align:start position:0% +Banks were sort of very resilient they + + + align:start position:0% +Banks were sort of very resilient they +had lot of capital and so on there + + align:start position:0% +had lot of capital and so on there + + + align:start position:0% +had lot of capital and so on there +wasn't a lot of concern that that would + + align:start position:0% +wasn't a lot of concern that that would + + + align:start position:0% +wasn't a lot of concern that that would +be an issue in the US because again the + + align:start position:0% +be an issue in the US because again the + + + align:start position:0% +be an issue in the US because again the +the big Banks look very healthy uh + + align:start position:0% +the big Banks look very healthy uh + + + align:start position:0% +the big Banks look very healthy uh +deposits were flowing out of big Banks + + align:start position:0% +deposits were flowing out of big Banks + + + align:start position:0% +deposits were flowing out of big Banks +but it was happening all at a normal + + align:start position:0% +but it was happening all at a normal + + + align:start position:0% +but it was happening all at a normal +Pace it's normal that deposits go out of + + align:start position:0% +Pace it's normal that deposits go out of + + + align:start position:0% +Pace it's normal that deposits go out of +the banking sector when interest rates + + align:start position:0% +the banking sector when interest rates + + + align:start position:0% +the banking sector when interest rates +are to rise uh but there was no sign of + + align:start position:0% +are to rise uh but there was no sign of + + + align:start position:0% +are to rise uh but there was no sign of +major trouble well that changed a month + + align:start position:0% +major trouble well that changed a month + + + align:start position:0% +major trouble well that changed a month +ago as you well know and something broke + + align:start position:0% +ago as you well know and something broke + + + align:start position:0% +ago as you well know and something broke +finally no and that the major episode + + align:start position:0% +finally no and that the major episode + + + align:start position:0% +finally no and that the major episode +there was the Silicon Valley Bank know + + align:start position:0% +there was the Silicon Valley Bank know + + + align:start position:0% +there was the Silicon Valley Bank know +we Al saw a big bank bank run there and + + align:start position:0% +we Al saw a big bank bank run there and + + + align:start position:0% +we Al saw a big bank bank run there and +eventually that bank collapsed and since + + align:start position:0% +eventually that bank collapsed and since + + + align:start position:0% +eventually that bank collapsed and since +then things have looked a little more + + align:start position:0% +then things have looked a little more + + + align:start position:0% +then things have looked a little more +complicated so here you have for example + + align:start position:0% +complicated so here you have for example + + + align:start position:0% +complicated so here you have for example +a a Commercial Bank deposits as I said + + align:start position:0% +a a Commercial Bank deposits as I said + + + align:start position:0% +a a Commercial Bank deposits as I said +as I said as the FED began to hike so + + align:start position:0% +as I said as the FED began to hike so + + + align:start position:0% +as I said as the FED began to hike so +focus on the red line the FED began to + + align:start position:0% +focus on the red line the FED began to + + + align:start position:0% +focus on the red line the FED began to +hike rates then H deposits began to + + align:start position:0% +hike rates then H deposits began to + + + align:start position:0% +hike rates then H deposits began to +people began to move their money out of + + align:start position:0% +people began to move their money out of + + + align:start position:0% +people began to move their money out of +deposit into US treasuries money market + + align:start position:0% +deposit into US treasuries money market + + + align:start position:0% +deposit into US treasuries money market +funds things of that kind that was + + align:start position:0% +funds things of that kind that was + + + align:start position:0% +funds things of that kind that was +normal okay and that didn't lead to a + + align:start position:0% +normal okay and that didn't lead to a + + + align:start position:0% +normal okay and that didn't lead to a +big cut in lending which is what you + + align:start position:0% +big cut in lending which is what you + + + align:start position:0% +big cut in lending which is what you +worried about when when Banks lose + + align:start position:0% +worried about when when Banks lose + + + align:start position:0% +worried about when when Banks lose +funding but things began to change quite + + align:start position:0% +funding but things began to change quite + + + align:start position:0% +funding but things began to change quite +rapidly well in the second half of 2022 + + align:start position:0% +rapidly well in the second half of 2022 + + + align:start position:0% +rapidly well in the second half of 2022 +this was perceived felt mostly by large + + align:start position:0% +this was perceived felt mostly by large + + + align:start position:0% +this was perceived felt mostly by large +Banks and when deposits decline + + align:start position:0% +Banks and when deposits decline + + + align:start position:0% +Banks and when deposits decline +gradually in large Banks that's not such + + align:start position:0% +gradually in large Banks that's not such + + + align:start position:0% +gradually in large Banks that's not such +a big issue because deposits are not the + + align:start position:0% +a big issue because deposits are not the + + + align:start position:0% +a big issue because deposits are not the +only funding source that that big banks + + align:start position:0% +only funding source that that big banks + + + align:start position:0% +only funding source that that big banks +have they have many other sources of + + align:start position:0% +have they have many other sources of + + + align:start position:0% +have they have many other sources of +funding H but then things that's what + + align:start position:0% +funding H but then things that's what + + + align:start position:0% +funding H but then things that's what +happens this year things accelerated + + align:start position:0% +happens this year things accelerated + + + align:start position:0% +happens this year things accelerated +very very quickly H this year and so + + align:start position:0% +very very quickly H this year and so + + + align:start position:0% +very very quickly H this year and so +this is different this is a different + + align:start position:0% +this is different this is a different + + + align:start position:0% +this is different this is a different +animal from this sort of very controlled + + align:start position:0% +animal from this sort of very controlled + + + align:start position:0% +animal from this sort of very controlled +decline in deposits as interest we're + + align:start position:0% +decline in deposits as interest we're + + + align:start position:0% +decline in deposits as interest we're +hiking this is a very sharp decline in + + align:start position:0% +hiking this is a very sharp decline in + + + align:start position:0% +hiking this is a very sharp decline in +deposits okay uh so that's a problem + + align:start position:0% +deposits okay uh so that's a problem + + + align:start position:0% +deposits okay uh so that's a problem +because that that's an avoid + + align:start position:0% +because that that's an avoid + + + align:start position:0% +because that that's an avoid +will hit lending okay so that's when to + + align:start position:0% +will hit lending okay so that's when to + + + align:start position:0% +will hit lending okay so that's when to +show up in terms of the moldes we have + + align:start position:0% +show up in terms of the moldes we have + + + align:start position:0% +show up in terms of the moldes we have +had if you were to use your ISL MPC + + align:start position:0% +had if you were to use your ISL MPC + + + align:start position:0% +had if you were to use your ISL MPC +model it would show up as an increas in + + align:start position:0% +model it would show up as an increas in + + + align:start position:0% +model it would show up as an increas in +X remember we had premium and stuff like + + align:start position:0% +X remember we had premium and stuff like + + + align:start position:0% +X remember we had premium and stuff like +that well that's a way you probably + + align:start position:0% +that well that's a way you probably + + + align:start position:0% +that well that's a way you probably +could model what is happening right + + align:start position:0% +could model what is happening right + + + align:start position:0% +could model what is happening right +now now one of the big as I said before + + align:start position:0% +now now one of the big as I said before + + + align:start position:0% +now now one of the big as I said before +these are in different Scala so a small + + align:start position:0% +these are in different Scala so a small + + + align:start position:0% +these are in different Scala so a small +Bank deposits on the left large Banks + + align:start position:0% +Bank deposits on the left large Banks + + + align:start position:0% +Bank deposits on the left large Banks +deposit on the on the right + + align:start position:0% +deposit on the on the right + + + align:start position:0% +deposit on the on the right +as I said before through most of of this + + align:start position:0% +as I said before through most of of this + + + align:start position:0% +as I said before through most of of this +episode in which deposits were declining + + align:start position:0% +episode in which deposits were declining + + + align:start position:0% +episode in which deposits were declining +in the in the banking + + align:start position:0% +in the in the banking + + + align:start position:0% +in the in the banking +sector it was mostly a phenomenon that + + align:start position:0% +sector it was mostly a phenomenon that + + + align:start position:0% +sector it was mostly a phenomenon that +was that that affected large Banks and + + align:start position:0% +was that that affected large Banks and + + + align:start position:0% +was that that affected large Banks and +it was very grad okay but what happened + + align:start position:0% +it was very grad okay but what happened + + + align:start position:0% +it was very grad okay but what happened +since a month ago is essentially small + + align:start position:0% +since a month ago is essentially small + + + align:start position:0% +since a month ago is essentially small +and mediumsized Banks experien a very + + align:start position:0% +and mediumsized Banks experien a very + + + align:start position:0% +and mediumsized Banks experien a very +large running deposits part of that went + + align:start position:0% +large running deposits part of that went + + + align:start position:0% +large running deposits part of that went +to money market us treasuries and and + + align:start position:0% +to money market us treasuries and and + + + align:start position:0% +to money market us treasuries and and +part of it you don't see different scale + + align:start position:0% +part of it you don't see different scale + + + align:start position:0% +part of it you don't see different scale +and + + align:start position:0% +and + + + align:start position:0% +and +but it went actually to large Banks it + + align:start position:0% +but it went actually to large Banks it + + + align:start position:0% +but it went actually to large Banks it +was relocation it's called that's called + + align:start position:0% +was relocation it's called that's called + + + align:start position:0% +was relocation it's called that's called +flight to Quality okay now even if if if + + align:start position:0% +flight to Quality okay now even if if if + + + align:start position:0% +flight to Quality okay now even if if if +this has been a full relocation of of H + + align:start position:0% +this has been a full relocation of of H + + + align:start position:0% +this has been a full relocation of of H +deposits from large bank to from small + + align:start position:0% +deposits from large bank to from small + + + align:start position:0% +deposits from large bank to from small +Banks to large Banks and so no deposit + + align:start position:0% +Banks to large Banks and so no deposit + + + align:start position:0% +Banks to large Banks and so no deposit +would have declined in the whole banking + + align:start position:0% +would have declined in the whole banking + + + align:start position:0% +would have declined in the whole banking +sector that would have consequences for + + align:start position:0% +sector that would have consequences for + + + align:start position:0% +sector that would have consequences for +the economy because these type of banks + + align:start position:0% +the economy because these type of banks + + + align:start position:0% +the economy because these type of banks +don't lend to the same type of + + align:start position:0% +don't lend to the same type of + + + align:start position:0% +don't lend to the same type of +people small Banks small especially + + align:start position:0% +people small Banks small especially + + + align:start position:0% +people small Banks small especially +Regional Banks lend a lot to people that + + align:start position:0% +Regional Banks lend a lot to people that + + + align:start position:0% +Regional Banks lend a lot to people that +to businesses and people that do not + + align:start position:0% +to businesses and people that do not + + + align:start position:0% +to businesses and people that do not +have other sources of funding they tend + + align:start position:0% +have other sources of funding they tend + + + align:start position:0% +have other sources of funding they tend +to be small businesses and so on the + + align:start position:0% +to be small businesses and so on the + + + align:start position:0% +to be small businesses and so on the +only way they can get borrow is either + + align:start position:0% +only way they can get borrow is either + + + align:start position:0% +only way they can get borrow is either +from the family or from a bank but they + + align:start position:0% +from the family or from a bank but they + + + align:start position:0% +from the family or from a bank but they +cannot issue bonds and things like that + + align:start position:0% +cannot issue bonds and things like that + + + align:start position:0% +cannot issue bonds and things like that +no and so they don't have other sources + + align:start position:0% +no and so they don't have other sources + + + align:start position:0% +no and so they don't have other sources +of + + align:start position:0% +of + + + align:start position:0% +of +funding and so that's the problem + + align:start position:0% +funding and so that's the problem + + + align:start position:0% +funding and so that's the problem +because what you see here is naturally + + align:start position:0% +because what you see here is naturally + + + align:start position:0% +because what you see here is naturally +when you start seeing deposits going out + + align:start position:0% +when you start seeing deposits going out + + + align:start position:0% +when you start seeing deposits going out +there have been also H losses + + align:start position:0% +there have been also H losses + + + align:start position:0% +there have been also H losses +experienced by the Banks because they + + align:start position:0% +experienced by the Banks because they + + + align:start position:0% +experienced by the Banks because they +had to recognize the losses in the asset + + align:start position:0% +had to recognize the losses in the asset + + + align:start position:0% +had to recognize the losses in the asset +side once they lost deposit is that they + + align:start position:0% +side once they lost deposit is that they + + + align:start position:0% +side once they lost deposit is that they +had to cut lending and you can see here + + align:start position:0% +had to cut lending and you can see here + + + align:start position:0% +had to cut lending and you can see here +what has been happening to lending large + + align:start position:0% +what has been happening to lending large + + + align:start position:0% +what has been happening to lending large +Banks they began to slow down here but + + align:start position:0% +Banks they began to slow down here but + + + align:start position:0% +Banks they began to slow down here but +it's a gradual slow down you have seen a + + align:start position:0% +it's a gradual slow down you have seen a + + + align:start position:0% +it's a gradual slow down you have seen a +very sharp decline in lending over the + + align:start position:0% +very sharp decline in lending over the + + + align:start position:0% +very sharp decline in lending over the +last three or four weeks okay so we're + + align:start position:0% +last three or four weeks okay so we're + + + align:start position:0% +last three or four weeks okay so we're +in the early phases what we like to call + + align:start position:0% +in the early phases what we like to call + + + align:start position:0% +in the early phases what we like to call +as described as a credit crunch okay and + + align:start position:0% +as described as a credit crunch okay and + + + align:start position:0% +as described as a credit crunch okay and +um now that's a the problem as I said + + align:start position:0% +um now that's a the problem as I said + + + align:start position:0% +um now that's a the problem as I said +before because those + + align:start position:0% +before because those + + + align:start position:0% +before because those +banks these Banks Banks in Gray here are + + align:start position:0% +banks these Banks Banks in Gray here are + + + align:start position:0% +banks these Banks Banks in Gray here are +the banks that lend primarily to small + + align:start position:0% +the banks that lend primarily to small + + + align:start position:0% +the banks that lend primarily to small +and medium-sized businesses okay so you + + align:start position:0% +and medium-sized businesses okay so you + + + align:start position:0% +and medium-sized businesses okay so you +see here the share of + + align:start position:0% +see here the share of + + + align:start position:0% +see here the share of +commercial H and Industrial loans by + + align:start position:0% +commercial H and Industrial loans by + + + align:start position:0% +commercial H and Industrial loans by +Bank size H and this is loans to small + + align:start position:0% +Bank size H and this is loans to small + + + align:start position:0% +Bank size H and this is loans to small +businesses loan to larger business these + + align:start position:0% +businesses loan to larger business these + + + align:start position:0% +businesses loan to larger business these +are the banks that are in grade before + + align:start position:0% +are the banks that are in grade before + + + align:start position:0% +are the banks that are in grade before +below $250 billion and you see that that + + align:start position:0% +below $250 billion and you see that that + + + align:start position:0% +below $250 billion and you see that that +they have a large share of loans to + + align:start position:0% +they have a large share of loans to + + + align:start position:0% +they have a large share of loans to +small businesses okay so those sectors + + align:start position:0% +small businesses okay so those sectors + + + align:start position:0% +small businesses okay so those sectors +are going to suff suffer a lot so + + align:start position:0% +are going to suff suffer a lot so + + + align:start position:0% +are going to suff suffer a lot so +there's going to be a a contraction in + + align:start position:0% +there's going to be a a contraction in + + + align:start position:0% +there's going to be a a contraction in +the economy and it's going to be very + + align:start position:0% +the economy and it's going to be very + + + align:start position:0% +the economy and it's going to be very +concentrated on the small businesses + + align:start position:0% +concentrated on the small businesses + + + align:start position:0% +concentrated on the small businesses +mediumsized businesses and so on and + + align:start position:0% +mediumsized businesses and so on and + + + align:start position:0% +mediumsized businesses and so on and +again it's more problematic a + + align:start position:0% +again it's more problematic a + + + align:start position:0% +again it's more problematic a +contraction in lending to those + + align:start position:0% +contraction in lending to those + + + align:start position:0% +contraction in lending to those +businesses because they don't have + + align:start position:0% +businesses because they don't have + + + align:start position:0% +businesses because they don't have +alternative sources of funding that's it + + align:start position:0% +alternative sources of funding that's it + + + align:start position:0% +alternative sources of funding that's it +okay it's either return earnings the + + align:start position:0% +okay it's either return earnings the + + + align:start position:0% +okay it's either return earnings the +family if it is really really small or H + + align:start position:0% +family if it is really really small or H + + + align:start position:0% +family if it is really really small or H +ER + + align:start position:0% + + + + align:start position:0% + +Banks again big corporations these guys + + align:start position:0% +Banks again big corporations these guys + + + align:start position:0% +Banks again big corporations these guys +probably have are borrowing from 10 + + align:start position:0% +probably have are borrowing from 10 + + + align:start position:0% +probably have are borrowing from 10 +different banks and and and they have + + align:start position:0% +different banks and and and they have + + + align:start position:0% +different banks and and and they have +issued corporate bonds and and they even + + align:start position:0% +issued corporate bonds and and they even + + + align:start position:0% +issued corporate bonds and and they even +have commercial paper this a entirely + + align:start position:0% +have commercial paper this a entirely + + + align:start position:0% +have commercial paper this a entirely +different life when you live here than + + align:start position:0% +different life when you live here than + + + align:start position:0% +different life when you live here than +when you live + + align:start position:0% +when you live + + + align:start position:0% +when you live +here H if you look by sectors that also + + align:start position:0% +here H if you look by sectors that also + + + align:start position:0% +here H if you look by sectors that also +is going to have implications for + + align:start position:0% +is going to have implications for + + + align:start position:0% +is going to have implications for +sectors so this is going to be clearly + + align:start position:0% +sectors so this is going to be clearly + + + align:start position:0% +sectors so this is going to be clearly +contractionary but it's not going to be + + align:start position:0% +contractionary but it's not going to be + + + align:start position:0% +contractionary but it's not going to be +equally contractionary it will depend on + + align:start position:0% +equally contractionary it will depend on + + + align:start position:0% +equally contractionary it will depend on +the composition of your sectors and not + + align:start position:0% +the composition of your sectors and not + + + align:start position:0% +the composition of your sectors and not +all sectors have the same share of small + + align:start position:0% +all sectors have the same share of small + + + align:start position:0% +all sectors have the same share of small +businesses and and and mediumsized + + align:start position:0% +businesses and and and mediumsized + + + align:start position:0% +businesses and and and mediumsized +businesses you see here the construction + + align:start position:0% +businesses you see here the construction + + + align:start position:0% +businesses you see here the construction +services a very large share most of the + + align:start position:0% +services a very large share most of the + + + align:start position:0% +services a very large share most of the +more than half of the businesses in + + align:start position:0% +more than half of the businesses in + + + align:start position:0% +more than half of the businesses in +construction are really small or + + align:start position:0% +construction are really small or + + + align:start position:0% +construction are really small or +mediumsized businesses okay H big + + align:start position:0% +mediumsized businesses okay H big + + + align:start position:0% +mediumsized businesses okay H big +contract with utilities where sort of + + align:start position:0% +contract with utilities where sort of + + + align:start position:0% +contract with utilities where sort of +they are all big businesses and so on + + align:start position:0% +they are all big businesses and so on + + + align:start position:0% +they are all big businesses and so on +okay so so big dispersion and so this is + + align:start position:0% +okay so so big dispersion and so this is + + + align:start position:0% +okay so so big dispersion and so this is +going to be a contraction is going to be + + align:start position:0% +going to be a contraction is going to be + + + align:start position:0% +going to be a contraction is going to be +very felt is felt very strongly here at + + align:start position:0% +very felt is felt very strongly here at + + + align:start position:0% +very felt is felt very strongly here at +the top + + align:start position:0% +the top + + + align:start position:0% +the top +okay so that's what is happening right + + align:start position:0% +okay so that's what is happening right + + + align:start position:0% +okay so that's what is happening right +now and from the point of view of the + + align:start position:0% +now and from the point of view of the + + + align:start position:0% +now and from the point of view of the +aggregate essentially where we have gone + + align:start position:0% +aggregate essentially where we have gone + + + align:start position:0% +aggregate essentially where we have gone +is from a path like this to a path like + + align:start position:0% +is from a path like this to a path like + + + align:start position:0% +is from a path like this to a path like +that so the economy was overheating so + + align:start position:0% +that so the economy was overheating so + + + align:start position:0% +that so the economy was overheating so +we need to slow down the economy there's + + align:start position:0% +we need to slow down the economy there's + + + align:start position:0% +we need to slow down the economy there's +no way around that output was above + + align:start position:0% +no way around that output was above + + + align:start position:0% +no way around that output was above +potential output that was causing + + align:start position:0% +potential output that was causing + + + align:start position:0% +potential output that was causing +inflationary pressure we needed to bring + + align:start position:0% +inflationary pressure we needed to bring + + + align:start position:0% +inflationary pressure we needed to bring +this stuff down and the economy was + + align:start position:0% +this stuff down and the economy was + + + align:start position:0% +this stuff down and the economy was +slowing down but it was happening at + + align:start position:0% +slowing down but it was happening at + + + align:start position:0% +slowing down but it was happening at +sort of a very slow pace and that was a + + align:start position:0% +sort of a very slow pace and that was a + + + align:start position:0% +sort of a very slow pace and that was a +bit exas exasperating for the FED but it + + align:start position:0% +bit exas exasperating for the FED but it + + + align:start position:0% +bit exas exasperating for the FED but it +was happening very very slowly among + + align:start position:0% +was happening very very slowly among + + + align:start position:0% +was happening very very slowly among +other things because of the balance + + align:start position:0% +other things because of the balance + + + align:start position:0% +other things because of the balance +sheets of the household sector and + + align:start position:0% +sheets of the household sector and + + + align:start position:0% +sheets of the household sector and +corporations in general was so very + + align:start position:0% +corporations in general was so very + + + align:start position:0% +corporations in general was so very +healthy but now things are accelerating + + align:start position:0% +healthy but now things are accelerating + + + align:start position:0% +healthy but now things are accelerating +very quickly because once you produce + + align:start position:0% +very quickly because once you produce + + + align:start position:0% +very quickly because once you produce +credit CR credit constraints and things + + align:start position:0% +credit CR credit constraints and things + + + align:start position:0% +credit CR credit constraints and things +like that like that so of the same + + align:start position:0% +like that like that so of the same + + + align:start position:0% +like that like that so of the same +declines in wealth that we were + + align:start position:0% +declines in wealth that we were + + + align:start position:0% +declines in wealth that we were +experienced before that were dragging + + align:start position:0% +experienced before that were dragging + + + align:start position:0% +experienced before that were dragging +aggregate demand down have a much larger + + align:start position:0% +aggregate demand down have a much larger + + + align:start position:0% +aggregate demand down have a much larger +effect and so we're changing from some a + + align:start position:0% +effect and so we're changing from some a + + + align:start position:0% +effect and so we're changing from some a +world that look like that to world it's + + align:start position:0% +world that look like that to world it's + + + align:start position:0% +world that look like that to world it's +going to look a lot more like this and + + align:start position:0% +going to look a lot more like this and + + + align:start position:0% +going to look a lot more like this and +that's tricky for the central bank + + align:start position:0% +that's tricky for the central bank + + + align:start position:0% +that's tricky for the central bank +because now the FED needs to before + + align:start position:0% +because now the FED needs to before + + + align:start position:0% +because now the FED needs to before +there was no way around they had to hike + + align:start position:0% +there was no way around they had to hike + + + align:start position:0% +there was no way around they had to hike +interest rate H because the main problem + + align:start position:0% +interest rate H because the main problem + + + align:start position:0% +interest rate H because the main problem +was inflation now they know that as they + + align:start position:0% +was inflation now they know that as they + + + align:start position:0% +was inflation now they know that as they +hike interest rate they still need to + + align:start position:0% +hike interest rate they still need to + + + align:start position:0% +hike interest rate they still need to +hike interest rate I think unless it is + + align:start position:0% +hike interest rate I think unless it is + + + align:start position:0% +hike interest rate I think unless it is +a big mess ER because inflation is still + + align:start position:0% +a big mess ER because inflation is still + + + align:start position:0% +a big mess ER because inflation is still +way above their target ER but they have + + align:start position:0% +way above their target ER but they have + + + align:start position:0% +way above their target ER but they have +to be very worried that this stuff + + align:start position:0% +to be very worried that this stuff + + + align:start position:0% +to be very worried that this stuff +doesn't become to + + align:start position:0% +doesn't become to + + + align:start position:0% +doesn't become to +steep the things get to be very + + align:start position:0% +steep the things get to be very + + + align:start position:0% +steep the things get to be very +nonlinear when the financial sector is + + align:start position:0% +nonlinear when the financial sector is + + + align:start position:0% +nonlinear when the financial sector is +involved and and so probably that means + + align:start position:0% +involved and and so probably that means + + + align:start position:0% +involved and and so probably that means +that on net they already did it in the + + align:start position:0% +that on net they already did it in the + + + align:start position:0% +that on net they already did it in the +previous meeting everyone anticipated 50 + + align:start position:0% +previous meeting everyone anticipated 50 + + + align:start position:0% +previous meeting everyone anticipated 50 +basis points of hikes once svb happened + + align:start position:0% +basis points of hikes once svb happened + + + align:start position:0% +basis points of hikes once svb happened +the bets went down dramatically and the + + align:start position:0% +the bets went down dramatically and the + + + align:start position:0% +the bets went down dramatically and the +realization went down to 25 basis points + + align:start position:0% +realization went down to 25 basis points + + + align:start position:0% +realization went down to 25 basis points +and so that's where we are H now now if + + align:start position:0% +and so that's where we are H now now if + + + align:start position:0% +and so that's where we are H now now if +everything works as + + align:start position:0% +everything works as + + + align:start position:0% +everything works as +plan and more or less that's a forecast + + align:start position:0% +plan and more or less that's a forecast + + + align:start position:0% +plan and more or less that's a forecast +at this moment there isn't any panic and + + align:start position:0% +at this moment there isn't any panic and + + + align:start position:0% +at this moment there isn't any panic and +so on + + align:start position:0% +so on + + + align:start position:0% +so on +is that we're going to experience not a + + align:start position:0% +is that we're going to experience not a + + + align:start position:0% +is that we're going to experience not a +technically a recession but significant + + align:start position:0% +technically a recession but significant + + + align:start position:0% +technically a recession but significant +slowdown in in in the next quarters or + + align:start position:0% +slowdown in in in the next quarters or + + + align:start position:0% +slowdown in in in the next quarters or +so okay so that that's that's what that + + align:start position:0% +so okay so that that's that's what that + + + align:start position:0% +so okay so that that's that's what that +sort of the consensus expecting to to + + align:start position:0% +sort of the consensus expecting to to + + + align:start position:0% +sort of the consensus expecting to to +see H as a result of all these combined + + align:start position:0% +see H as a result of all these combined + + + align:start position:0% +see H as a result of all these combined +forces the effect that it still needs to + + align:start position:0% +forces the effect that it still needs to + + + align:start position:0% +forces the effect that it still needs to +tighten because of aggregate demand + + align:start position:0% +tighten because of aggregate demand + + + align:start position:0% +tighten because of aggregate demand +reasons and the very negative effect of + + align:start position:0% +reasons and the very negative effect of + + + align:start position:0% +reasons and the very negative effect of +the credit crunch especially on certain + + align:start position:0% +the credit crunch especially on certain + + + align:start position:0% +the credit crunch especially on certain +parts of the economy okay but that's + + align:start position:0% +parts of the economy okay but that's + + + align:start position:0% +parts of the economy okay but that's +what if everything again it works as + + align:start position:0% +what if everything again it works as + + + align:start position:0% +what if everything again it works as +plan means things continue to go Fairly + + align:start position:0% +plan means things continue to go Fairly + + + align:start position:0% +plan means things continue to go Fairly +smoothly H then it's certainly not going + + align:start position:0% +smoothly H then it's certainly not going + + + align:start position:0% +smoothly H then it's certainly not going +to be a a good year for economic + + align:start position:0% +to be a a good year for economic + + + align:start position:0% +to be a a good year for economic +activity ER but it shouldn't be a + + align:start position:0% +activity ER but it shouldn't be a + + + align:start position:0% +activity ER but it shouldn't be a +disaster either and that's sort of where + + align:start position:0% +disaster either and that's sort of where + + + align:start position:0% +disaster either and that's sort of where +we are at and and the tension is well if + + align:start position:0% +we are at and and the tension is well if + + + align:start position:0% +we are at and and the tension is well if +the financial crisis sort + + align:start position:0% +the financial crisis sort + + + align:start position:0% +the financial crisis sort +of leaks into the larger Banks then then + + align:start position:0% +of leaks into the larger Banks then then + + + align:start position:0% +of leaks into the larger Banks then then +these numbers are going to get a lot + + align:start position:0% +these numbers are going to get a lot + + + align:start position:0% +these numbers are going to get a lot +worse of course but that's that's that's + + align:start position:0% +worse of course but that's that's that's + + + align:start position:0% +worse of course but that's that's that's +a concern at the moment but uh but it + + align:start position:0% +a concern at the moment but uh but it + + + align:start position:0% +a concern at the moment but uh but it +doesn't seem like the central scenario + + align:start position:0% +doesn't seem like the central scenario + + + align:start position:0% +doesn't seem like the central scenario +now there are also some good news + + align:start position:0% +now there are also some good news + + + align:start position:0% +now there are also some good news +happening because remember that the + + align:start position:0% +happening because remember that the + + + align:start position:0% +happening because remember that the +problem we have the problem you have + + align:start position:0% +problem we have the problem you have + + + align:start position:0% +problem we have the problem you have +comes from two sides one side is too + + align:start position:0% +comes from two sides one side is too + + + align:start position:0% +comes from two sides one side is too +much demand and that the FED can affect + + align:start position:0% +much demand and that the FED can affect + + + align:start position:0% +much demand and that the FED can affect +very quickly that's that's what it's + + align:start position:0% +very quickly that's that's what it's + + + align:start position:0% +very quickly that's that's what it's +doing by hiking interest rate not as + + align:start position:0% +doing by hiking interest rate not as + + + align:start position:0% +doing by hiking interest rate not as +quickly as they would like but still + + align:start position:0% +quickly as they would like but still + + + align:start position:0% +quickly as they would like but still +they they have an impact on that but the + + align:start position:0% +they they have an impact on that but the + + + align:start position:0% +they they have an impact on that but the +other problem was aggregate supply and + + align:start position:0% +other problem was aggregate supply and + + + align:start position:0% +other problem was aggregate supply and +in particular is that the labor market + + align:start position:0% +in particular is that the labor market + + + align:start position:0% +in particular is that the labor market +look very tight and remember when we did + + align:start position:0% +look very tight and remember when we did + + + align:start position:0% +look very tight and remember when we did +the Philips curve and all that the labor + + align:start position:0% +the Philips curve and all that the labor + + + align:start position:0% +the Philips curve and all that the labor +market is very critical in all that + + align:start position:0% +market is very critical in all that + + + align:start position:0% +market is very critical in all that +process of generating inflation and so + + align:start position:0% +process of generating inflation and so + + + align:start position:0% +process of generating inflation and so +on that's a reason you sort of try to + + align:start position:0% +on that's a reason you sort of try to + + + align:start position:0% +on that's a reason you sort of try to +generate more unemployment essentially + + align:start position:0% +generate more unemployment essentially + + + align:start position:0% +generate more unemployment essentially +to lower wage pressure because that + + align:start position:0% +to lower wage pressure because that + + + align:start position:0% +to lower wage pressure because that +means less pressure on prices and so on + + align:start position:0% +means less pressure on prices and so on + + + align:start position:0% +means less pressure on prices and so on +so forth and one of the problems is that + + align:start position:0% +so forth and one of the problems is that + + + align:start position:0% +so forth and one of the problems is that +again looks is very nice in principle + + align:start position:0% +again looks is very nice in principle + + + align:start position:0% +again looks is very nice in principle +that we have very low unemployment rate + + align:start position:0% +that we have very low unemployment rate + + + align:start position:0% +that we have very low unemployment rate +but it's very difficult to sort of lower + + align:start position:0% +but it's very difficult to sort of lower + + + align:start position:0% +but it's very difficult to sort of lower +wage pressure If unemployment is so low + + align:start position:0% + + + + align:start position:0% + +having said this and this is the part + + align:start position:0% +having said this and this is the part + + + align:start position:0% +having said this and this is the part +that I say is sort of Fairly good news + + align:start position:0% +that I say is sort of Fairly good news + + + align:start position:0% +that I say is sort of Fairly good news +having said this in the mod we simplify + + align:start position:0% +having said this in the mod we simplify + + + align:start position:0% +having said this in the mod we simplify +things and we just put an employment as + + align:start position:0% +things and we just put an employment as + + + align:start position:0% +things and we just put an employment as +the only variable that could adjust and + + align:start position:0% +the only variable that could adjust and + + + align:start position:0% +the only variable that could adjust and +that was important for wages as aside + + align:start position:0% +that was important for wages as aside + + + align:start position:0% +that was important for wages as aside +from some institutional things in + + align:start position:0% +from some institutional things in + + + align:start position:0% +from some institutional things in +practice there are many other indicators + + align:start position:0% +practice there are many other indicators + + + align:start position:0% +practice there are many other indicators +and really what really matters is + + align:start position:0% +and really what really matters is + + + align:start position:0% +and really what really matters is +employment what happens we took as a + + align:start position:0% +employment what happens we took as a + + + align:start position:0% +employment what happens we took as a +fixed n we took a fixed the + + align:start position:0% +fixed n we took a fixed the + + + align:start position:0% +fixed n we took a fixed the +participation rate and that's the reason + + align:start position:0% +participation rate and that's the reason + + + align:start position:0% +participation rate and that's the reason +unemployment was the variable summarize + + align:start position:0% +unemployment was the variable summarize + + + align:start position:0% +unemployment was the variable summarize +everything but what really puts pressure + + align:start position:0% +everything but what really puts pressure + + + align:start position:0% +everything but what really puts pressure +on labor market is shortage of workers + + align:start position:0% +on labor market is shortage of workers + + + align:start position:0% +on labor market is shortage of workers +if you have an unemployment rate that is + + align:start position:0% +if you have an unemployment rate that is + + + align:start position:0% +if you have an unemployment rate that is +constant but there are lots of workers + + align:start position:0% +constant but there are lots of workers + + + align:start position:0% +constant but there are lots of workers +have coming into the labor force and + + align:start position:0% +have coming into the labor force and + + + align:start position:0% +have coming into the labor force and +that's not doesn't put as much pressure + + align:start position:0% +that's not doesn't put as much pressure + + + align:start position:0% +that's not doesn't put as much pressure +on on wages and therefore less pressure + + align:start position:0% +on on wages and therefore less pressure + + + align:start position:0% +on on wages and therefore less pressure +on inflation and this is exactly what we + + align:start position:0% +on inflation and this is exactly what we + + + align:start position:0% +on inflation and this is exactly what we +beginning to see in the US economy and I + + align:start position:0% +beginning to see in the US economy and I + + + align:start position:0% +beginning to see in the US economy and I +think that's very good news it gives us + + align:start position:0% +think that's very good news it gives us + + + align:start position:0% +think that's very good news it gives us +hope that this inflationary process may + + align:start position:0% +hope that this inflationary process may + + + align:start position:0% +hope that this inflationary process may +come down a little faster so this is + + align:start position:0% +come down a little faster so this is + + + align:start position:0% +come down a little faster so this is +labor market participation remember so + + align:start position:0% +labor market participation remember so + + + align:start position:0% +labor market participation remember so +this unemployment number + + align:start position:0% +this unemployment number + + + align:start position:0% +this unemployment number +spike a lot but it under represented how + + align:start position:0% +spike a lot but it under represented how + + + align:start position:0% +spike a lot but it under represented how +much contraction there was in labor in + + align:start position:0% +much contraction there was in labor in + + + align:start position:0% +much contraction there was in labor in +employment and so on because many people + + align:start position:0% +employment and so on because many people + + + align:start position:0% +employment and so on because many people +simply exit the labor force and those + + align:start position:0% +simply exit the labor force and those + + + align:start position:0% +simply exit the labor force and those +remember we don't count as an employed + + align:start position:0% +remember we don't count as an employed + + + align:start position:0% +remember we don't count as an employed +okay and so that happened it was a very + + align:start position:0% +okay and so that happened it was a very + + + align:start position:0% +okay and so that happened it was a very +sharp decline in the in the labor force + + align:start position:0% +sharp decline in the in the labor force + + + align:start position:0% +sharp decline in the in the labor force +in the labor participation rate so + + align:start position:0% +in the labor participation rate so + + + align:start position:0% +in the labor participation rate so +decline in the labor force and then that + + align:start position:0% +decline in the labor force and then that + + + align:start position:0% +decline in the labor force and then that +recovery is one of the things that + + align:start position:0% +recovery is one of the things that + + + align:start position:0% +recovery is one of the things that +happened much slower than the FED + + align:start position:0% +happened much slower than the FED + + + align:start position:0% +happened much slower than the FED +anticipated and that was part of the + + align:start position:0% +anticipated and that was part of the + + + align:start position:0% +anticipated and that was part of the +mistake is they thought that this was + + align:start position:0% +mistake is they thought that this was + + + align:start position:0% +mistake is they thought that this was +going to come back quickly and that for + + align:start position:0% +going to come back quickly and that for + + + align:start position:0% +going to come back quickly and that for +potential output was going to rise very + + align:start position:0% +potential output was going to rise very + + + align:start position:0% +potential output was going to rise very +quickly and it didn't that was one of + + align:start position:0% +quickly and it didn't that was one of + + + align:start position:0% +quickly and it didn't that was one of +the the the mistakes the forast mistakes + + align:start position:0% +the the the mistakes the forast mistakes + + + align:start position:0% +the the the mistakes the forast mistakes +but now it's clearly it's coming back to + + align:start position:0% +but now it's clearly it's coming back to + + + align:start position:0% +but now it's clearly it's coming back to +levels that are sort of more consistent + + align:start position:0% +levels that are sort of more consistent + + + align:start position:0% +levels that are sort of more consistent +with historical + + align:start position:0% +with historical + + + align:start position:0% +with historical +levels if you look at the employment to + + align:start position:0% +levels if you look at the employment to + + + align:start position:0% +levels if you look at the employment to +population ratio also big decline for + + align:start position:0% +population ratio also big decline for + + + align:start position:0% +population ratio also big decline for +similar reasons but if you look at + + align:start position:0% +similar reasons but if you look at + + + align:start position:0% +similar reasons but if you look at +employment to population ratio today is + + align:start position:0% +employment to population ratio today is + + + align:start position:0% +employment to population ratio today is +clearly sort of getting back to the + + align:start position:0% +clearly sort of getting back to the + + + align:start position:0% +clearly sort of getting back to the +trend it had before okay so so that's + + align:start position:0% +trend it had before okay so so that's + + + align:start position:0% +trend it had before okay so so that's +that's very good news in the sense that + + align:start position:0% +that's very good news in the sense that + + + align:start position:0% +that's very good news in the sense that +even if unemployment doesn't move a lot + + align:start position:0% +even if unemployment doesn't move a lot + + + align:start position:0% +even if unemployment doesn't move a lot +this sort of reduces well it's good for + + align:start position:0% +this sort of reduces well it's good for + + + align:start position:0% +this sort of reduces well it's good for +output expands and so on but it also + + align:start position:0% +output expands and so on but it also + + + align:start position:0% +output expands and so on but it also +lowers the pre inflationary pressures in + + align:start position:0% +lowers the pre inflationary pressures in + + + align:start position:0% +lowers the pre inflationary pressures in +the economy and another component that + + align:start position:0% +the economy and another component that + + + align:start position:0% +the economy and another component that +actually that that I think I mentioned a + + align:start position:0% +actually that that I think I mentioned a + + + align:start position:0% +actually that that I think I mentioned a +couple of times in in the lecture but is + + align:start position:0% +couple of times in in the lecture but is + + + align:start position:0% +couple of times in in the lecture but is +immigration in in a market like the us a + + align:start position:0% +immigration in in a market like the us a + + + align:start position:0% +immigration in in a market like the us a +lot of the labor forces comes from + + align:start position:0% +lot of the labor forces comes from + + + align:start position:0% +lot of the labor forces comes from +immigration okay and and that stopped + + align:start position:0% +immigration okay and and that stopped + + + align:start position:0% +immigration okay and and that stopped +for a while for a variety of reasons but + + align:start position:0% +for a while for a variety of reasons but + + + align:start position:0% +for a while for a variety of reasons but +certainly Co had a a big effect so so + + align:start position:0% +certainly Co had a a big effect so so + + + align:start position:0% +certainly Co had a a big effect so so +that meant sort of about + + align:start position:0% +that meant sort of about + + + align:start position:0% +that meant sort of about +500,000 less people a year coming into + + align:start position:0% +500,000 less people a year coming into + + + align:start position:0% +500,000 less people a year coming into +the US Labor Force and that has big + + align:start position:0% +the US Labor Force and that has big + + + align:start position:0% +the US Labor Force and that has big +impacts especially in some sectors of + + align:start position:0% +impacts especially in some sectors of + + + align:start position:0% +impacts especially in some sectors of +the economy okay lots of and and that's + + align:start position:0% +the economy okay lots of and and that's + + + align:start position:0% +the economy okay lots of and and that's +clearly being fixed now okay we may have + + align:start position:0% +clearly being fixed now okay we may have + + + align:start position:0% +clearly being fixed now okay we may have +other problems people may fight for + + align:start position:0% +other problems people may fight for + + + align:start position:0% +other problems people may fight for +political reasons and the SS whatever + + align:start position:0% +political reasons and the SS whatever + + + align:start position:0% +political reasons and the SS whatever +but from the point of view of macro this + + align:start position:0% +but from the point of view of macro this + + + align:start position:0% +but from the point of view of macro this +is certainly helping okay and in fact if + + align:start position:0% +is certainly helping okay and in fact if + + + align:start position:0% +is certainly helping okay and in fact if +you look at where the wage pressure is + + align:start position:0% +you look at where the wage pressure is + + + align:start position:0% +you look at where the wage pressure is +really coming from in the US economy is + + align:start position:0% +really coming from in the US economy is + + + align:start position:0% +really coming from in the US economy is +coming from those sectors where sort of + + align:start position:0% +coming from those sectors where sort of + + + align:start position:0% +coming from those sectors where sort of +immigrants play a big role you know um + + align:start position:0% +immigrants play a big role you know um + + + align:start position:0% +immigrants play a big role you know um +accommodation Food Services stuff like + + align:start position:0% +accommodation Food Services stuff like + + + align:start position:0% +accommodation Food Services stuff like +that you see that there sort of wages + + align:start position:0% +that you see that there sort of wages + + + align:start position:0% +that you see that there sort of wages +Rose pretty dramatically because there + + align:start position:0% +Rose pretty dramatically because there + + + align:start position:0% +Rose pretty dramatically because there +was a massive shortage there for two + + align:start position:0% +was a massive shortage there for two + + + align:start position:0% +was a massive shortage there for two +reasons one people didn't want to go + + align:start position:0% +reasons one people didn't want to go + + + align:start position:0% +reasons one people didn't want to go +back to those sectors to work close + + align:start position:0% +back to those sectors to work close + + + align:start position:0% +back to those sectors to work close +contact and stuff like that and the + + align:start position:0% +contact and stuff like that and the + + + align:start position:0% +contact and stuff like that and the +other one is that the important flow of + + align:start position:0% +other one is that the important flow of + + + align:start position:0% +other one is that the important flow of +supply of workers into that had sort of + + align:start position:0% +supply of workers into that had sort of + + + align:start position:0% +supply of workers into that had sort of +slowed down quite dramatically okay so + + align:start position:0% +slowed down quite dramatically okay so + + + align:start position:0% +slowed down quite dramatically okay so +that's where we're at and as a result of + + align:start position:0% +that's where we're at and as a result of + + + align:start position:0% +that's where we're at and as a result of +all these good forces despite the fact + + align:start position:0% +all these good forces despite the fact + + + align:start position:0% +all these good forces despite the fact +that we have very low + + align:start position:0% +that we have very low + + + align:start position:0% +that we have very low +unemployment you can see that wage + + align:start position:0% +unemployment you can see that wage + + + align:start position:0% +unemployment you can see that wage +pressure is beginning to decline in the + + align:start position:0% +pressure is beginning to decline in the + + + align:start position:0% +pressure is beginning to decline in the +US okay so it was very high there but + + align:start position:0% +US okay so it was very high there but + + + align:start position:0% +US okay so it was very high there but +those numbers are very distorted by + + align:start position:0% +those numbers are very distorted by + + + align:start position:0% +those numbers are very distorted by +composition effects and stuff like that + + align:start position:0% +composition effects and stuff like that + + + align:start position:0% +composition effects and stuff like that +but these were the numbers that were + + align:start position:0% +but these were the numbers that were + + + align:start position:0% +but these were the numbers that were +very worrisome I mean with wage + + align:start position:0% +very worrisome I mean with wage + + + align:start position:0% +very worrisome I mean with wage +inflation of 6% it's going to be very + + align:start position:0% +inflation of 6% it's going to be very + + + align:start position:0% +inflation of 6% it's going to be very +difficult to bring inflation to 2% down + + align:start position:0% +difficult to bring inflation to 2% down + + + align:start position:0% +difficult to bring inflation to 2% down +you need much lower wag inflation but + + align:start position:0% +you need much lower wag inflation but + + + align:start position:0% +you need much lower wag inflation but +you see that that is beginning to + + align:start position:0% +you see that that is beginning to + + + align:start position:0% +you see that that is beginning to +decline 2% is still too high for a + + align:start position:0% +decline 2% is still too high for a + + + align:start position:0% +decline 2% is still too high for a +steady state if you want to go back to + + align:start position:0% +steady state if you want to go back to + + + align:start position:0% +steady state if you want to go back to +2% inflation rate because you can have + + align:start position:0% +2% inflation rate because you can have + + + align:start position:0% +2% inflation rate because you can have +an increase in real wage but that has to + + align:start position:0% +an increase in real wage but that has to + + + align:start position:0% +an increase in real wage but that has to +be more or less aligned with the rate of + + align:start position:0% +be more or less aligned with the rate of + + + align:start position:0% +be more or less aligned with the rate of +growth of + + align:start position:0% +growth of + + + align:start position:0% +growth of +productivity which is much lower than + + align:start position:0% +productivity which is much lower than + + + align:start position:0% +productivity which is much lower than +that I mean at best it's 1% one and a + + align:start position:0% +that I mean at best it's 1% one and a + + + align:start position:0% +that I mean at best it's 1% one and a +half sometimes but so you could live + + align:start position:0% +half sometimes but so you could live + + + align:start position:0% +half sometimes but so you could live +with three and a half% weight real + + align:start position:0% +with three and a half% weight real + + + align:start position:0% +with three and a half% weight real +nominal wage growth but four four and a + + align:start position:0% +nominal wage growth but four four and a + + + align:start position:0% +nominal wage growth but four four and a +half it's it's a bit too much + + align:start position:0% +half it's it's a bit too much + + + align:start position:0% +half it's it's a bit too much +okay anyway so that's a that's that's + + align:start position:0% +okay anyway so that's a that's that's + + + align:start position:0% +okay anyway so that's a that's that's +the state of economy any questions about + + align:start position:0% +the state of economy any questions about + + + align:start position:0% +the state of economy any questions about +the state of economy open questions + + align:start position:0% +the state of economy open questions + + + align:start position:0% +the state of economy open questions +no no you're happy with it I'm fine good + + align:start position:0% +no no you're happy with it I'm fine good + + + align:start position:0% +no no you're happy with it I'm fine good +okay good so so what I want to next is + + align:start position:0% +okay good so so what I want to next is + + + align:start position:0% +okay good so so what I want to next is +so this was a summary and I all that I + + align:start position:0% +so this was a summary and I all that I + + + align:start position:0% +so this was a summary and I all that I +did here I did close economy economics + + align:start position:0% +did here I did close economy economics + + + align:start position:0% +did here I did close economy economics +okay all the my description I didn't + + align:start position:0% +okay all the my description I didn't + + + align:start position:0% +okay all the my description I didn't +need to tell you what was happening in + + align:start position:0% +need to tell you what was happening in + + + align:start position:0% +need to tell you what was happening in +the rest of the world and so on that + + align:start position:0% +the rest of the world and so on that + + + align:start position:0% +the rest of the world and so on that +would have been a lot harder to do if if + + align:start position:0% +would have been a lot harder to do if if + + + align:start position:0% +would have been a lot harder to do if if +if this was Singapore for example + + align:start position:0% +if this was Singapore for example + + + align:start position:0% +if this was Singapore for example +because Singapore depends a lot on the + + align:start position:0% +because Singapore depends a lot on the + + + align:start position:0% +because Singapore depends a lot on the +rest of the world and it's very + + align:start position:0% +rest of the world and it's very + + + align:start position:0% +rest of the world and it's very +difficult to tell a story that just + + align:start position:0% +difficult to tell a story that just + + + align:start position:0% +difficult to tell a story that just +depends on what happen in Singapore the + + align:start position:0% +depends on what happen in Singapore the + + + align:start position:0% +depends on what happen in Singapore the +US is pretty unique in that you can tell + + align:start position:0% +US is pretty unique in that you can tell + + + align:start position:0% +US is pretty unique in that you can tell +most of the story based on what happens + + align:start position:0% +most of the story based on what happens + + + align:start position:0% +most of the story based on what happens +in the US most not all but most of the + + align:start position:0% +in the US most not all but most of the + + + align:start position:0% +in the US most not all but most of the +story and that's what I just did almost + + align:start position:0% +story and that's what I just did almost + + + align:start position:0% +story and that's what I just did almost +anywhere else you need to think about + + align:start position:0% +anywhere else you need to think about + + + align:start position:0% +anywhere else you need to think about +even if you're in Japan big economy and + + align:start position:0% +even if you're in Japan big economy and + + + align:start position:0% +even if you're in Japan big economy and +so on effects will play a big role and + + align:start position:0% +so on effects will play a big role and + + + align:start position:0% +so on effects will play a big role and +so when you describe the state of the + + align:start position:0% +so when you describe the state of the + + + align:start position:0% +so when you describe the state of the +economy you're going to be talking about + + align:start position:0% +economy you're going to be talking about + + + align:start position:0% +economy you're going to be talking about +the Yen very high very low or + + align:start position:0% +the Yen very high very low or + + + align:start position:0% +the Yen very high very low or +not here you don't worry much about the + + align:start position:0% +not here you don't worry much about the + + + align:start position:0% +not here you don't worry much about the +dollar but the US is very unique on + + align:start position:0% +dollar but the US is very unique on + + + align:start position:0% +dollar but the US is very unique on +that I think no other country in the + + align:start position:0% +that I think no other country in the + + + align:start position:0% +that I think no other country in the +world has that that feature okay so now + + align:start position:0% +world has that that feature okay so now + + + align:start position:0% +world has that that feature okay so now +we're going to open up the economy and + + align:start position:0% +we're going to open up the economy and + + + align:start position:0% +we're going to open up the economy and +again perhaps it's it's the least + + align:start position:0% +again perhaps it's it's the least + + + align:start position:0% +again perhaps it's it's the least +important for the us but anywhere else + + align:start position:0% +important for the us but anywhere else + + + align:start position:0% +important for the us but anywhere else +is tremendously important more so it's + + align:start position:0% +is tremendously important more so it's + + + align:start position:0% +is tremendously important more so it's +becoming increasingly important for the + + align:start position:0% +becoming increasingly important for the + + + align:start position:0% +becoming increasingly important for the +US it has been becoming increasingly + + align:start position:0% +US it has been becoming increasingly + + + align:start position:0% +US it has been becoming increasingly +important for the US now we're in the + + align:start position:0% +important for the US now we're in the + + + align:start position:0% +important for the US now we're in the +middle of a de globalization mess we + + align:start position:0% +middle of a de globalization mess we + + + align:start position:0% +middle of a de globalization mess we +shall see where we end up so there has + + align:start position:0% +shall see where we end up so there has + + + align:start position:0% +shall see where we end up so there has +been a bit of a reversion of a very + + align:start position:0% +been a bit of a reversion of a very + + + align:start position:0% +been a bit of a reversion of a very +strong Trend towards integrating the + + align:start position:0% +strong Trend towards integrating the + + + align:start position:0% +strong Trend towards integrating the +economies of the world through many + + align:start position:0% +economies of the world through many + + + align:start position:0% +economies of the world through many +different channels and so I want to talk + + align:start position:0% +different channels and so I want to talk + + + align:start position:0% +different channels and so I want to talk +about what are the key variables in the + + align:start position:0% +about what are the key variables in the + + + align:start position:0% +about what are the key variables in the +when you integrate an economy to the + + align:start position:0% +when you integrate an economy to the + + + align:start position:0% +when you integrate an economy to the +rest of the world and and and things of + + align:start position:0% +rest of the world and and and things of + + + align:start position:0% +rest of the world and and and things of +that kind H I'm going to start with some + + align:start position:0% +that kind H I'm going to start with some + + + align:start position:0% +that kind H I'm going to start with some +definitions what are variables are we're + + align:start position:0% +definitions what are variables are we're + + + align:start position:0% +definitions what are variables are we're +going to be talking about that we + + align:start position:0% +going to be talking about that we + + + align:start position:0% +going to be talking about that we +weren't talking about up to now so one + + align:start position:0% +weren't talking about up to now so one + + + align:start position:0% +weren't talking about up to now so one +of the things that's going to be very + + align:start position:0% +of the things that's going to be very + + + align:start position:0% +of the things that's going to be very +important in an open economy exchange + + align:start position:0% +important in an open economy exchange + + + align:start position:0% +important in an open economy exchange +rate okay and here I'm giv you I'm going + + align:start position:0% +rate okay and here I'm giv you I'm going + + + align:start position:0% +rate okay and here I'm giv you I'm going +to Define things very formally later on + + align:start position:0% +to Define things very formally later on + + + align:start position:0% +to Define things very formally later on +but but but here you see an + + align:start position:0% +but but but here you see an + + + align:start position:0% +but but but here you see an +example of the US dollar Visa the main + + align:start position:0% +example of the US dollar Visa the main + + + align:start position:0% +example of the US dollar Visa the main +trading partners the US trades with many + + align:start position:0% +trading partners the US trades with many + + + align:start position:0% +trading partners the US trades with many +different parts of the world and there's + + align:start position:0% +different parts of the world and there's + + + align:start position:0% +different parts of the world and there's +an bilateral effects between those + + align:start position:0% +an bilateral effects between those + + + align:start position:0% +an bilateral effects between those +things and this measure here is + + align:start position:0% +things and this measure here is + + + align:start position:0% +things and this measure here is +something that weights by the amount of + + align:start position:0% +something that weights by the amount of + + + align:start position:0% +something that weights by the amount of +trade that we have with different + + align:start position:0% +trade that we have with different + + + align:start position:0% +trade that we have with different +economies of the world trace the + + align:start position:0% +economies of the world trace the + + + align:start position:0% +economies of the world trace the +different effects and says well is the + + align:start position:0% +different effects and says well is the + + + align:start position:0% +different effects and says well is the +dollar strong weak or whatever + + align:start position:0% +dollar strong weak or whatever + + + align:start position:0% +dollar strong weak or whatever +this is a matter of convention there's + + align:start position:0% +this is a matter of convention there's + + + align:start position:0% +this is a matter of convention there's +many ways you can no there are two ways + + align:start position:0% +many ways you can no there are two ways + + + align:start position:0% +many ways you can no there are two ways +in which you can do it but we're going + + align:start position:0% +in which you can do it but we're going + + + align:start position:0% +in which you can do it but we're going +to do it the following way what this + + align:start position:0% +to do it the following way what this + + + align:start position:0% +to do it the following way what this +effects will reflect is the price of the + + align:start position:0% +effects will reflect is the price of the + + + align:start position:0% +effects will reflect is the price of the +domestic currency in foreign currency + + align:start position:0% +domestic currency in foreign currency + + + align:start position:0% +domestic currency in foreign currency +terms so that means when this goes up + + align:start position:0% +terms so that means when this goes up + + + align:start position:0% +terms so that means when this goes up +means the dollar was becoming very + + align:start position:0% +means the dollar was becoming very + + + align:start position:0% +means the dollar was becoming very +expensive okay and that's a that's a + + align:start position:0% +expensive okay and that's a that's a + + + align:start position:0% +expensive okay and that's a that's a +very sharp I I'll get back to it but we + + align:start position:0% +very sharp I I'll get back to it but we + + + align:start position:0% +very sharp I I'll get back to it but we +call that an appreciation of the + + align:start position:0% +call that an appreciation of the + + + align:start position:0% +call that an appreciation of the +currency okay so here the the dollar was + + align:start position:0% +currency okay so here the the dollar was + + + align:start position:0% +currency okay so here the the dollar was +becoming very expensive in terms of + + align:start position:0% +becoming very expensive in terms of + + + align:start position:0% +becoming very expensive in terms of +other + + align:start position:0% +other + + + align:start position:0% +other +currencies the opposite happened sort of + + align:start position:0% +currencies the opposite happened sort of + + + align:start position:0% +currencies the opposite happened sort of +starting the second half of 2022 and now + + align:start position:0% +starting the second half of 2022 and now + + + align:start position:0% +starting the second half of 2022 and now +we have some had some Cycles here during + + align:start position:0% +we have some had some Cycles here during + + + align:start position:0% +we have some had some Cycles here during +this year but that's sort of that's + + align:start position:0% +this year but that's sort of that's + + + align:start position:0% +this year but that's sort of that's +going to be a very important variable + + align:start position:0% +going to be a very important variable + + + align:start position:0% +going to be a very important variable +the FX we call it the FX exchange + + align:start position:0% + + + + align:start position:0% + +rate another variable that we haven't + + align:start position:0% +rate another variable that we haven't + + + align:start position:0% +rate another variable that we haven't +talked about but but that is going to be + + align:start position:0% +talked about but but that is going to be + + + align:start position:0% +talked about but but that is going to be +important here is is and and that + + align:start position:0% +important here is is and and that + + + align:start position:0% +important here is is and and that +politicians argue a lot about it for + + align:start position:0% +politicians argue a lot about it for + + + align:start position:0% +politicians argue a lot about it for +with the wrong arguments but but but + + align:start position:0% +with the wrong arguments but but but + + + align:start position:0% +with the wrong arguments but but but +they do ER is the trades balance trade + + align:start position:0% +they do ER is the trades balance trade + + + align:start position:0% +they do ER is the trades balance trade +trade balance of goods and services of + + align:start position:0% +trade balance of goods and services of + + + align:start position:0% +trade balance of goods and services of +goods and services so this the trade + + align:start position:0% +goods and services so this the trade + + + align:start position:0% +goods and services so this the trade +balance of goods and services is simply + + align:start position:0% +balance of goods and services is simply + + + align:start position:0% +balance of goods and services is simply +a er um the difference between the + + align:start position:0% +a er um the difference between the + + + align:start position:0% +a er um the difference between the +exports so what a country sells to the + + align:start position:0% +exports so what a country sells to the + + + align:start position:0% +exports so what a country sells to the +rest of the world versus its import that + + align:start position:0% +rest of the world versus its import that + + + align:start position:0% +rest of the world versus its import that +is how much it buys from the rest of the + + align:start position:0% +is how much it buys from the rest of the + + + align:start position:0% +is how much it buys from the rest of the +world okay so this is monthly data for + + align:start position:0% +world okay so this is monthly data for + + + align:start position:0% +world okay so this is monthly data for +the US + + align:start position:0% +the US + + + align:start position:0% +the US +the US nowadays sort of runs a deficit a + + align:start position:0% +the US nowadays sort of runs a deficit a + + + align:start position:0% +the US nowadays sort of runs a deficit a +trade balance deficit of the order of 7 + + align:start position:0% +trade balance deficit of the order of 7 + + + align:start position:0% +trade balance deficit of the order of 7 +70 billion dollars a + + align:start position:0% +70 billion dollars a + + + align:start position:0% +70 billion dollars a +month that means it exports to the rest + + align:start position:0% +month that means it exports to the rest + + + align:start position:0% +month that means it exports to the rest +of the world about S no 70 billion + + align:start position:0% +of the world about S no 70 billion + + + align:start position:0% +of the world about S no 70 billion +dollar less than it Imports sorry sorry + + align:start position:0% +dollar less than it Imports sorry sorry + + + align:start position:0% +dollar less than it Imports sorry sorry +yeah seven less than it Imports perfect + + align:start position:0% +yeah seven less than it Imports perfect + + + align:start position:0% +yeah seven less than it Imports perfect +okay you have seen that this is + + align:start position:0% +okay you have seen that this is + + + align:start position:0% +okay you have seen that this is +pretty H sustained + + align:start position:0% +pretty H sustained + + + align:start position:0% +pretty H sustained +actually here look pretty balanced but + + align:start position:0% +actually here look pretty balanced but + + + align:start position:0% +actually here look pretty balanced but +but but but the US on on on average has + + align:start position:0% +but but but the US on on on average has + + + align:start position:0% +but but but the US on on on average has +a situation like that okay the US tends + + align:start position:0% +a situation like that okay the US tends + + + align:start position:0% +a situation like that okay the US tends +to export less than it Imports and then + + align:start position:0% +to export less than it Imports and then + + + align:start position:0% +to export less than it Imports and then +that's when politicians get all very + + align:start position:0% +that's when politicians get all very + + + align:start position:0% +that's when politicians get all very +worked out and said you know this is + + align:start position:0% +worked out and said you know this is + + + align:start position:0% +worked out and said you know this is +unfair competition from the rest of the + + align:start position:0% +unfair competition from the rest of the + + + align:start position:0% +unfair competition from the rest of the +world and so on so forth I think in + + align:start position:0% +world and so on so forth I think in + + + align:start position:0% +world and so on so forth I think in +general has very little to do with that + + align:start position:0% +general has very little to do with that + + + align:start position:0% +general has very little to do with that +it has to do that with the fact that the + + align:start position:0% +it has to do that with the fact that the + + + align:start position:0% +it has to do that with the fact that the +US likes to save less than the rest of + + align:start position:0% +US likes to save less than the rest of + + + align:start position:0% +US likes to save less than the rest of +the world and and but but let me not get + + align:start position:0% +the world and and but but let me not get + + + align:start position:0% +the world and and but but let me not get +into that and think much later in the + + align:start position:0% +into that and think much later in the + + + align:start position:0% +into that and think much later in the +course but anyway that's the situation + + align:start position:0% +course but anyway that's the situation + + + align:start position:0% +course but anyway that's the situation +for the + + align:start position:0% +for the + + + align:start position:0% +for the +US this is obviously a blep that has to + + align:start position:0% +US this is obviously a blep that has to + + + align:start position:0% +US this is obviously a blep that has to +do with covid and so on but you see that + + align:start position:0% +do with covid and so on but you see that + + + align:start position:0% +do with covid and so on but you see that +we're now more or less back to to where + + align:start position:0% +we're now more or less back to to where + + + align:start position:0% +we're now more or less back to to where +we were before this was a period + + align:start position:0% +we were before this was a period + + + align:start position:0% +we were before this was a period +actually of lots of global political + + align:start position:0% +actually of lots of global political + + + align:start position:0% +actually of lots of global political +tension because it had one counterpart + + align:start position:0% +tension because it had one counterpart + + + align:start position:0% +tension because it had one counterpart +that was very big it was + + align:start position:0% +that was very big it was + + + align:start position:0% +that was very big it was +China okay and it is called the the time + + align:start position:0% +China okay and it is called the the time + + + align:start position:0% +China okay and it is called the the time +of the global + + align:start position:0% +of the global + + + align:start position:0% +of the global +imbalances and that the US was learning + + align:start position:0% +imbalances and that the US was learning + + + align:start position:0% +imbalances and that the US was learning +very large trade deficits and then China + + align:start position:0% +very large trade deficits and then China + + + align:start position:0% +very large trade deficits and then China +in particular was running very large + + align:start position:0% +in particular was running very large + + + align:start position:0% +in particular was running very large +trade surpluses and and so there were + + align:start position:0% +trade surpluses and and so there were + + + align:start position:0% +trade surpluses and and so there were +lots of political quarters because of + + align:start position:0% +lots of political quarters because of + + + align:start position:0% +lots of political quarters because of +that here you have a so obviously the US + + align:start position:0% +that here you have a so obviously the US + + + align:start position:0% +that here you have a so obviously the US +has many many trading partners and with + + align:start position:0% +has many many trading partners and with + + + align:start position:0% +has many many trading partners and with +respect to many of them it has very + + align:start position:0% +respect to many of them it has very + + + align:start position:0% +respect to many of them it has very +large deficits so on net and here are + + align:start position:0% +large deficits so on net and here are + + + align:start position:0% +large deficits so on net and here are +the main I rank the the 10 main net + + align:start position:0% +the main I rank the the 10 main net + + + align:start position:0% +the main I rank the the 10 main net +deficits for the us so I don't know when + + align:start position:0% +deficits for the us so I don't know when + + + align:start position:0% +deficits for the us so I don't know when +was this but anyway it looks like that + + align:start position:0% +was this but anyway it looks like that + + + align:start position:0% +was this but anyway it looks like that +sort of for the + + align:start position:0% +sort of for the + + + align:start position:0% +sort of for the +last eight or so + + align:start position:0% +last eight or so + + + align:start position:0% +last eight or so +years remove Co it looks more or less + + align:start position:0% +years remove Co it looks more or less + + + align:start position:0% +years remove Co it looks more or less +like this all the time and you see that + + align:start position:0% +like this all the time and you see that + + + align:start position:0% +like this all the time and you see that +the US indeed large + + align:start position:0% +the US indeed large + + + align:start position:0% +the US indeed large +large exports to China about $153 + + align:start position:0% +large exports to China about $153 + + + align:start position:0% +large exports to China about $153 +billion a year and it Imports about 536 + + align:start position:0% +billion a year and it Imports about 536 + + + align:start position:0% +billion a year and it Imports about 536 +billions a year so the net deficit is$ + + align:start position:0% +billions a year so the net deficit is$ + + + align:start position:0% +billions a year so the net deficit is$ +380 billion dollar a year and that's the + + align:start position:0% +380 billion dollar a year and that's the + + + align:start position:0% +380 billion dollar a year and that's the +reason this is a big political thing + + align:start position:0% +reason this is a big political thing + + + align:start position:0% +reason this is a big political thing +okay because it sounds + + align:start position:0% +okay because it sounds + + + align:start position:0% +okay because it sounds +like a big deficit but there are other + + align:start position:0% +like a big deficit but there are other + + + align:start position:0% +like a big deficit but there are other +countries with respect to Mexico 130 + + align:start position:0% +countries with respect to Mexico 130 + + + align:start position:0% +countries with respect to Mexico 130 +billion and so on the US exports a lot + + align:start position:0% +billion and so on the US exports a lot + + + align:start position:0% +billion and so on the US exports a lot +more to + + align:start position:0% +more to + + + align:start position:0% +more to +Mexico ER Vietnam a lot of what happens + + align:start position:0% +Mexico ER Vietnam a lot of what happens + + + align:start position:0% +Mexico ER Vietnam a lot of what happens +from Vietnam is really Chinese exports + + align:start position:0% +from Vietnam is really Chinese exports + + + align:start position:0% +from Vietnam is really Chinese exports +in this guys but but uh but there you + + align:start position:0% +in this guys but but uh but there you + + + align:start position:0% +in this guys but but uh but there you +see it okay there are many others + + align:start position:0% +see it okay there are many others + + + align:start position:0% +see it okay there are many others +Germany is always a a problem but uh a + + align:start position:0% +Germany is always a a problem but uh a + + + align:start position:0% +Germany is always a a problem but uh a +problem for somebody that his deficit as + + align:start position:0% +problem for somebody that his deficit as + + + align:start position:0% +problem for somebody that his deficit as +a problem + + align:start position:0% +a problem + + + align:start position:0% +a problem +uh and so on okay + + align:start position:0% + + + + align:start position:0% + +now that's a on the good side this is + + align:start position:0% +now that's a on the good side this is + + + align:start position:0% +now that's a on the good side this is +this is this what I was saying here is + + align:start position:0% +this is this what I was saying here is + + + align:start position:0% +this is this what I was saying here is +that you know one sense of openness is + + align:start position:0% +that you know one sense of openness is + + + align:start position:0% +that you know one sense of openness is +on the goods and services Market that + + align:start position:0% +on the goods and services Market that + + + align:start position:0% +on the goods and services Market that +you buy goods from the rest of the world + + align:start position:0% +you buy goods from the rest of the world + + + align:start position:0% +you buy goods from the rest of the world +the rest of the world buys goods from + + align:start position:0% +the rest of the world buys goods from + + + align:start position:0% +the rest of the world buys goods from +you sometimes these things are balanced + + align:start position:0% +you sometimes these things are balanced + + + align:start position:0% +you sometimes these things are balanced +sometimes they're not H when at the + + align:start position:0% +sometimes they're not H when at the + + + align:start position:0% +sometimes they're not H when at the +aggre level they're not balance for a + + align:start position:0% +aggre level they're not balance for a + + + align:start position:0% +aggre level they're not balance for a +very long period of time unless you're + + align:start position:0% +very long period of time unless you're + + + align:start position:0% +very long period of time unless you're +the US that often causes problems ER um + + align:start position:0% +the US that often causes problems ER um + + + align:start position:0% +the US that often causes problems ER um +but at the bilateral level if you look + + align:start position:0% +but at the bilateral level if you look + + + align:start position:0% +but at the bilateral level if you look +at any country we'll have situations + + align:start position:0% +at any country we'll have situations + + + align:start position:0% +at any country we'll have situations +like this some country where they export + + align:start position:0% +like this some country where they export + + + align:start position:0% +like this some country where they export +a lot to and import very little from and + + align:start position:0% +a lot to and import very little from and + + + align:start position:0% +a lot to and import very little from and +vice versa but that's the way the US + + align:start position:0% +vice versa but that's the way the US + + + align:start position:0% +vice versa but that's the way the US +looks another sense of openness which is + + align:start position:0% +looks another sense of openness which is + + + align:start position:0% +looks another sense of openness which is +very important is financial openness no + + align:start position:0% +very important is financial openness no + + + align:start position:0% +very important is financial openness no +meaning that you can also buy or save + + align:start position:0% +meaning that you can also buy or save + + + align:start position:0% +meaning that you can also buy or save +using foreign assets or domestic assets + + align:start position:0% +using foreign assets or domestic assets + + + align:start position:0% +using foreign assets or domestic assets +okay so you can buy a foreign asset + + align:start position:0% +okay so you can buy a foreign asset + + + align:start position:0% +okay so you can buy a foreign asset +perhaps not directly or most of you + + align:start position:0% +perhaps not directly or most of you + + + align:start position:0% +perhaps not directly or most of you +directly but you can do it through a + + align:start position:0% +directly but you can do it through a + + + align:start position:0% +directly but you can do it through a +broker and so on you can buy foreign + + align:start position:0% +broker and so on you can buy foreign + + + align:start position:0% +broker and so on you can buy foreign +assets or and foreigners buy lots of us + + align:start position:0% +assets or and foreigners buy lots of us + + + align:start position:0% +assets or and foreigners buy lots of us +assets okay that's a sense of openness + + align:start position:0% +assets okay that's a sense of openness + + + align:start position:0% +assets okay that's a sense of openness +in financial markets that you can buy + + align:start position:0% +in financial markets that you can buy + + + align:start position:0% +in financial markets that you can buy +you're not stuck with your own your + + align:start position:0% +you're not stuck with your own your + + + align:start position:0% +you're not stuck with your own your +country's financial asset you can also + + align:start position:0% +country's financial asset you can also + + + align:start position:0% +country's financial asset you can also +invest in other Count's Financial assets + + align:start position:0% +invest in other Count's Financial assets + + + align:start position:0% +invest in other Count's Financial assets +and vice + + align:start position:0% +and vice + + + align:start position:0% +and vice +versa those things probably you how I + + align:start position:0% +versa those things probably you how I + + + align:start position:0% +versa those things probably you how I +mean you notice trade openness a lot + + align:start position:0% +mean you notice trade openness a lot + + + align:start position:0% +mean you notice trade openness a lot +more probably than financial openness no + + align:start position:0% +more probably than financial openness no + + + align:start position:0% +more probably than financial openness no +because you're all the time buying + + align:start position:0% +because you're all the time buying + + + align:start position:0% +because you're all the time buying +imported goods and stuff like that + + align:start position:0% +imported goods and stuff like that + + + align:start position:0% +imported goods and stuff like that +H while you probably not involving lot + + align:start position:0% +H while you probably not involving lot + + + align:start position:0% +H while you probably not involving lot +of transactions of international + + align:start position:0% +of transactions of international + + + align:start position:0% +of transactions of international +financial instruments and so on but they + + align:start position:0% +financial instruments and so on but they + + + align:start position:0% +financial instruments and so on but they +are very large okay so if Pension funds + + align:start position:0% +are very large okay so if Pension funds + + + align:start position:0% +are very large okay so if Pension funds +and so on they're all involved in very + + align:start position:0% +and so on they're all involved in very + + + align:start position:0% +and so on they're all involved in very +large transactions in fact transactions + + align:start position:0% +large transactions in fact transactions + + + align:start position:0% +large transactions in fact transactions +in financial markets are an order of + + align:start position:0% +in financial markets are an order of + + + align:start position:0% +in financial markets are an order of +magnitude larger than transactions in + + align:start position:0% +magnitude larger than transactions in + + + align:start position:0% +magnitude larger than transactions in +the Goods Market very large and here you + + align:start position:0% +the Goods Market very large and here you + + + align:start position:0% +the Goods Market very large and here you +have an example of a + + align:start position:0% +have an example of a + + + align:start position:0% +have an example of a +by origin the the the you know foreign + + align:start position:0% +by origin the the the you know foreign + + + align:start position:0% +by origin the the the you know foreign +Holdings of us + + align:start position:0% +Holdings of us + + + align:start position:0% +Holdings of us +assets and this is in in in billions + + align:start position:0% +assets and this is in in in billions + + + align:start position:0% +assets and this is in in in billions +so these guys here this is China and + + align:start position:0% +so these guys here this is China and + + + align:start position:0% +so these guys here this is China and +Canada so have the largest and the UK + + align:start position:0% +Canada so have the largest and the UK + + + align:start position:0% +Canada so have the largest and the UK +those have sort of you know in the order + + align:start position:0% +those have sort of you know in the order + + + align:start position:0% +those have sort of you know in the order +of $2 + + align:start position:0% +of $2 + + + align:start position:0% +of $2 +trillion of us assets they're + + align:start position:0% +trillion of us assets they're + + + align:start position:0% +trillion of us assets they're +holding Japan should be here also L A + + align:start position:0% +holding Japan should be here also L A + + + align:start position:0% +holding Japan should be here also L A +there there it is + + align:start position:0% +there there it is + + + align:start position:0% +there there it is +yeah now in these two countries + + align:start position:0% +yeah now in these two countries + + + align:start position:0% +yeah now in these two countries +here a lot of those Holdings + + align:start position:0% +here a lot of those Holdings + + + align:start position:0% +here a lot of those Holdings +actually well particularly in China more + + align:start position:0% +actually well particularly in China more + + + align:start position:0% +actually well particularly in China more +than than in Japan in China is a little + + align:start position:0% +than than in Japan in China is a little + + + align:start position:0% +than than in Japan in China is a little +less than than Japan + + align:start position:0% +less than than Japan + + + align:start position:0% +less than than Japan +Japan they save a lot so they need to + + align:start position:0% +Japan they save a lot so they need to + + + align:start position:0% +Japan they save a lot so they need to +buy lots of financial assets and the US + + align:start position:0% +buy lots of financial assets and the US + + + align:start position:0% +buy lots of financial assets and the US +is as the main producer of financial + + align:start position:0% +is as the main producer of financial + + + align:start position:0% +is as the main producer of financial +Assets in the world so they save a lot + + align:start position:0% +Assets in the world so they save a lot + + + align:start position:0% +Assets in the world so they save a lot +on that but also the central bank + + align:start position:0% +on that but also the central bank + + + align:start position:0% +on that but also the central bank +because of currency intervention and so + + align:start position:0% +because of currency intervention and so + + + align:start position:0% +because of currency intervention and so +on buys lots of us + + align:start position:0% +on buys lots of us + + + align:start position:0% +on buys lots of us +treasuries China this is mostly the + + align:start position:0% +treasuries China this is mostly the + + + align:start position:0% +treasuries China this is mostly the +Central Bank buying US treasuries + + align:start position:0% +Central Bank buying US treasuries + + + align:start position:0% +Central Bank buying US treasuries +foreign reserves okay large amount of + + align:start position:0% +foreign reserves okay large amount of + + + align:start position:0% +foreign reserves okay large amount of +reserves Canada is private sector + + align:start position:0% +reserves Canada is private sector + + + align:start position:0% +reserves Canada is private sector +Pension funds and so on for but you see + + align:start position:0% +Pension funds and so on for but you see + + + align:start position:0% +Pension funds and so on for but you see +Brazilians also buy lots of assets from + + align:start position:0% +Brazilians also buy lots of assets from + + + align:start position:0% +Brazilians also buy lots of assets from +the US again central banks play big + + align:start position:0% +the US again central banks play big + + + align:start position:0% +the US again central banks play big +roles in all this Australia is less the + + align:start position:0% +roles in all this Australia is less the + + + align:start position:0% +roles in all this Australia is less the +Central Bank much more private sector UK + + align:start position:0% +Central Bank much more private sector UK + + + align:start position:0% +Central Bank much more private sector UK +is all private sector and so + + align:start position:0% +is all private sector and so + + + align:start position:0% +is all private sector and so +on and then Europe okay but point of + + align:start position:0% +on and then Europe okay but point of + + + align:start position:0% +on and then Europe okay but point of +that picture is that there's lots of + + align:start position:0% +that picture is that there's lots of + + + align:start position:0% +that picture is that there's lots of +countries in the world resent of + + align:start position:0% +countries in the world resent of + + + align:start position:0% +countries in the world resent of +different countries in the world that + + align:start position:0% +different countries in the world that + + + align:start position:0% +different countries in the world that +buy us Financial assets and in big + + align:start position:0% +buy us Financial assets and in big + + + align:start position:0% +buy us Financial assets and in big +amounts + + align:start position:0% +amounts + + + align:start position:0% +amounts +okay I don't know what the total number + + align:start position:0% +okay I don't know what the total number + + + align:start position:0% +okay I don't know what the total number +today is + + align:start position:0% + + + + align:start position:0% + +probably actually let me not make up + + align:start position:0% +probably actually let me not make up + + + align:start position:0% +probably actually let me not make up +that number you may find it + + align:start position:0% +that number you may find it + + + align:start position:0% +that number you may find it +um but it is certainly in + + align:start position:0% +um but it is certainly in + + + align:start position:0% +um but it is certainly in +the2 trillion dollar or something like + + align:start position:0% +the2 trillion dollar or something like + + + align:start position:0% +the2 trillion dollar or something like +that of H assets held us assets held by + + align:start position:0% +that of H assets held us assets held by + + + align:start position:0% +that of H assets held us assets held by +foreigners you can check it and tell me + + align:start position:0% +foreigners you can check it and tell me + + + align:start position:0% +foreigners you can check it and tell me +it's probably + + align:start position:0% +it's probably + + + align:start position:0% +it's probably +more here's the other way around us + + align:start position:0% +more here's the other way around us + + + align:start position:0% +more here's the other way around us +residents Holdings of foreign assets + + align:start position:0% +residents Holdings of foreign assets + + + align:start position:0% +residents Holdings of foreign assets +okay + + align:start position:0% +okay + + + align:start position:0% +okay +ER you see us + + align:start position:0% +ER you see us + + + align:start position:0% +ER you see us +us residents hold lots of Canadian + + align:start position:0% +us residents hold lots of Canadian + + + align:start position:0% +us residents hold lots of Canadian +assets okay and mostly developed + + align:start position:0% +assets okay and mostly developed + + + align:start position:0% +assets okay and mostly developed +economies but you have India China and + + align:start position:0% +economies but you have India China and + + + align:start position:0% +economies but you have India China and +so on lots of Latino American + + align:start position:0% +so on lots of Latino American + + + align:start position:0% +so on lots of Latino American +assets and so on okay so the US is so + + align:start position:0% +assets and so on okay so the US is so + + + align:start position:0% +assets and so on okay so the US is so +it's not only that the rest of the world + + align:start position:0% +it's not only that the rest of the world + + + align:start position:0% +it's not only that the rest of the world +demands us asset but us + + align:start position:0% +demands us asset but us + + + align:start position:0% +demands us asset but us +residents perhaps not directly most of + + align:start position:0% +residents perhaps not directly most of + + + align:start position:0% +residents perhaps not directly most of +you but indirectly demand lots of + + align:start position:0% +you but indirectly demand lots of + + + align:start position:0% +you but indirectly demand lots of +foreign assets okay um there are some + + align:start position:0% +foreign assets okay um there are some + + + align:start position:0% +foreign assets okay um there are some +very fascinating facts that happen here + + align:start position:0% +very fascinating facts that happen here + + + align:start position:0% +very fascinating facts that happen here +because the type of assets that + + align:start position:0% +because the type of assets that + + + align:start position:0% +because the type of assets that +foreigners tend to demand from the US + + align:start position:0% +foreigners tend to demand from the US + + + align:start position:0% +foreigners tend to demand from the US +are very different from the ones that + + align:start position:0% +are very different from the ones that + + + align:start position:0% +are very different from the ones that +us er um demands from the rest of the + + align:start position:0% +us er um demands from the rest of the + + + align:start position:0% +us er um demands from the rest of the +world ER in fact one of the things that + + align:start position:0% +world ER in fact one of the things that + + + align:start position:0% +world ER in fact one of the things that +that the reasons the US can afford + + align:start position:0% +that the reasons the US can afford + + + align:start position:0% +that the reasons the US can afford +running those chronic trade + + align:start position:0% +running those chronic trade + + + align:start position:0% +running those chronic trade +deficits is because it tends to get much + + align:start position:0% +deficits is because it tends to get much + + + align:start position:0% +deficits is because it tends to get much +higher Returns on the asset it buys + + align:start position:0% +higher Returns on the asset it buys + + + align:start position:0% +higher Returns on the asset it buys +abroad than foreigners get on the assets + + align:start position:0% +abroad than foreigners get on the assets + + + align:start position:0% +abroad than foreigners get on the assets +they buy in the US and the difference + + align:start position:0% +they buy in the US and the difference + + + align:start position:0% +they buy in the US and the difference +allows you to find sort of systematic + + align:start position:0% +allows you to find sort of systematic + + + align:start position:0% +allows you to find sort of systematic +trade deficits and the reason for that + + align:start position:0% +trade deficits and the reason for that + + + align:start position:0% +trade deficits and the reason for that +is a lot of the US assets that for buy + + align:start position:0% +is a lot of the US assets that for buy + + + align:start position:0% +is a lot of the US assets that for buy +they do it for safety reasons they're + + align:start position:0% +they do it for safety reasons they're + + + align:start position:0% +they do it for safety reasons they're +buying us treasure it's very safe + + align:start position:0% +buying us treasure it's very safe + + + align:start position:0% +buying us treasure it's very safe +instrument just in case there is a big + + align:start position:0% +instrument just in case there is a big + + + align:start position:0% +instrument just in case there is a big +mess they they want to have those assets + + align:start position:0% +mess they they want to have those assets + + + align:start position:0% +mess they they want to have those assets +so it's it's almost for insurance reason + + align:start position:0% +so it's it's almost for insurance reason + + + align:start position:0% +so it's it's almost for insurance reason +ER the US Treasures are sort of + + align:start position:0% +ER the US Treasures are sort of + + + align:start position:0% +ER the US Treasures are sort of +perceived as the main safe Assets in the + + align:start position:0% +perceived as the main safe Assets in the + + + align:start position:0% +perceived as the main safe Assets in the +world okay so they they hold it for for + + align:start position:0% +world okay so they they hold it for for + + + align:start position:0% +world okay so they they hold it for for +that reason while the US mostly hold + + align:start position:0% +that reason while the US mostly hold + + + align:start position:0% +that reason while the US mostly hold +assets abroad for a you know risky + + align:start position:0% +assets abroad for a you know risky + + + align:start position:0% +assets abroad for a you know risky +Investments either foreign direct + + align:start position:0% +Investments either foreign direct + + + align:start position:0% +Investments either foreign direct +investment or Equity stuff like that and + + align:start position:0% +investment or Equity stuff like that and + + + align:start position:0% +investment or Equity stuff like that and +typically most fixed income investments + + align:start position:0% +typically most fixed income investments + + + align:start position:0% +typically most fixed income investments +in the US a lot of it a lot of what you + + align:start position:0% +in the US a lot of it a lot of what you + + + align:start position:0% +in the US a lot of it a lot of what you +see here is just us resident reaching + + align:start position:0% +see here is just us resident reaching + + + align:start position:0% +see here is just us resident reaching +for + + align:start position:0% +for + + + align:start position:0% +for +yield + + align:start position:0% +yield + + + align:start position:0% +yield +Brazilian Sovereign bonds equivalence of + + align:start position:0% +Brazilian Sovereign bonds equivalence of + + + align:start position:0% +Brazilian Sovereign bonds equivalence of +the US treasuries you know give you 9% + + align:start position:0% +the US treasuries you know give you 9% + + + align:start position:0% +the US treasuries you know give you 9% +10% it's a lot higher than the US tends + + align:start position:0% +10% it's a lot higher than the US tends + + + align:start position:0% +10% it's a lot higher than the US tends +to give H 14% even now and so on so so + + align:start position:0% +to give H 14% even now and so on so so + + + align:start position:0% +to give H 14% even now and so on so so +so net the US tends to make + + align:start position:0% + + + + align:start position:0% + +has less Assets in the rest of the world + + align:start position:0% +has less Assets in the rest of the world + + + align:start position:0% +has less Assets in the rest of the world +than foreigners have of the US and it + + align:start position:0% +than foreigners have of the US and it + + + align:start position:0% +than foreigners have of the US and it +still makes sufficiently more return + + align:start position:0% +still makes sufficiently more return + + + align:start position:0% +still makes sufficiently more return +higher return on average on an asset it + + align:start position:0% +higher return on average on an asset it + + + align:start position:0% +higher return on average on an asset it +holds from the rest of the world that it + + align:start position:0% +holds from the rest of the world that it + + + align:start position:0% +holds from the rest of the world that it +has a surplus which which it can Finance + + align:start position:0% +has a surplus which which it can Finance + + + align:start position:0% +has a surplus which which it can Finance +the trade deficit This is complicated + + align:start position:0% +the trade deficit This is complicated + + + align:start position:0% +the trade deficit This is complicated +you don't need to know the details but I + + align:start position:0% +you don't need to know the details but I + + + align:start position:0% +you don't need to know the details but I +to tell you what the kind of things are + + align:start position:0% + + + + align:start position:0% + +happening so so there's three senses in + + align:start position:0% +happening so so there's three senses in + + + align:start position:0% +happening so so there's three senses in +which you can have a a and of of + + align:start position:0% +which you can have a a and of of + + + align:start position:0% +which you can have a a and of of +openness the two that I have described + + align:start position:0% +openness the two that I have described + + + align:start position:0% +openness the two that I have described +implicitly already Goods in Goods Market + + align:start position:0% +implicitly already Goods in Goods Market + + + align:start position:0% +implicitly already Goods in Goods Market +that you can + + align:start position:0% +that you can + + + align:start position:0% +that you can +buy foreign goods and you can sell Goods + + align:start position:0% +buy foreign goods and you can sell Goods + + + align:start position:0% +buy foreign goods and you can sell Goods +to the rest of the world and the second + + align:start position:0% +to the rest of the world and the second + + + align:start position:0% +to the rest of the world and the second +one is financial markets which is what I + + align:start position:0% +one is financial markets which is what I + + + align:start position:0% +one is financial markets which is what I +just described you can choose between + + align:start position:0% +just described you can choose between + + + align:start position:0% +just described you can choose between +domestic and foreign assets the main + + align:start position:0% +domestic and foreign assets the main + + + align:start position:0% +domestic and foreign assets the main +impediments to the forers typically are + + align:start position:0% +impediments to the forers typically are + + + align:start position:0% +impediments to the forers typically are +tariffs and quotas and you have heard a + + align:start position:0% +tariffs and quotas and you have heard a + + + align:start position:0% +tariffs and quotas and you have heard a +lot about tariffs and so on these days + + align:start position:0% +lot about tariffs and so on these days + + + align:start position:0% +lot about tariffs and so on these days +ER the main impediment for financial + + align:start position:0% +ER the main impediment for financial + + + align:start position:0% +ER the main impediment for financial +Market is what is called Capital + + align:start position:0% +Market is what is called Capital + + + align:start position:0% +Market is what is called Capital +controls very rarely develop economies + + align:start position:0% +controls very rarely develop economies + + + align:start position:0% +controls very rarely develop economies +impose Capital + + align:start position:0% +impose Capital + + + align:start position:0% +impose Capital +controls but emerging markets do it + + align:start position:0% +controls but emerging markets do it + + + align:start position:0% +controls but emerging markets do it +regularly okay H limit the amount of + + align:start position:0% +regularly okay H limit the amount of + + + align:start position:0% +regularly okay H limit the amount of +especially Capital outflows when lots of + + align:start position:0% +especially Capital outflows when lots of + + + align:start position:0% +especially Capital outflows when lots of +capitalist Le in the country they try to + + align:start position:0% +capitalist Le in the country they try to + + + align:start position:0% +capitalist Le in the country they try to +stop you from doing more of that and and + + align:start position:0% +stop you from doing more of that and and + + + align:start position:0% +stop you from doing more of that and and +they sometimes do it in the way in + + align:start position:0% +they sometimes do it in the way in + + + align:start position:0% +they sometimes do it in the way in +because they they want to avoid the + + align:start position:0% +because they they want to avoid the + + + align:start position:0% +because they they want to avoid the +micro instability that comes from the + + align:start position:0% +micro instability that comes from the + + + align:start position:0% +micro instability that comes from the +big reversal of capital flows so they + + align:start position:0% +big reversal of capital flows so they + + + align:start position:0% +big reversal of capital flows so they +don't let lots of capital flow in during + + align:start position:0% +don't let lots of capital flow in during + + + align:start position:0% +don't let lots of capital flow in during +the boom just to prevent + + align:start position:0% +the boom just to prevent + + + align:start position:0% +the boom just to prevent +a reversal later on that's capital + + align:start position:0% +a reversal later on that's capital + + + align:start position:0% +a reversal later on that's capital +controls and there's a third way of + + align:start position:0% +controls and there's a third way of + + + align:start position:0% +controls and there's a third way of +opening to the rest of the world H which + + align:start position:0% +opening to the rest of the world H which + + + align:start position:0% +opening to the rest of the world H which +is Factor markets okay which is that + + align:start position:0% +is Factor markets okay which is that + + + align:start position:0% +is Factor markets okay which is that +firms can choose location I mean some + + align:start position:0% +firms can choose location I mean some + + + align:start position:0% +firms can choose location I mean some +plants we're seeing you know Japanese + + align:start position:0% +plants we're seeing you know Japanese + + + align:start position:0% +plants we're seeing you know Japanese +plants that that that do not export + + align:start position:0% +plants that that that do not export + + + align:start position:0% +plants that that that do not export +Toyotas from directly from + + align:start position:0% +Toyotas from directly from + + + align:start position:0% +Toyotas from directly from +from from Japan they have the plant here + + align:start position:0% +from from Japan they have the plant here + + + align:start position:0% +from from Japan they have the plant here +either in Canada or somewhere in the US + + align:start position:0% +either in Canada or somewhere in the US + + + align:start position:0% +either in Canada or somewhere in the US +and they sell locally so that's that's + + align:start position:0% +and they sell locally so that's that's + + + align:start position:0% +and they sell locally so that's that's +relocation of factors of production + + align:start position:0% +relocation of factors of production + + + align:start position:0% +relocation of factors of production +Japanese Capital that relocates to some + + align:start position:0% +Japanese Capital that relocates to some + + + align:start position:0% +Japanese Capital that relocates to some +place in Canada or in the US and labor + + align:start position:0% +place in Canada or in the US and labor + + + align:start position:0% +place in Canada or in the US and labor +you can also have workers that move from + + align:start position:0% +you can also have workers that move from + + + align:start position:0% +you can also have workers that move from +one place to the other that's another + + align:start position:0% +one place to the other that's another + + + align:start position:0% +one place to the other that's another +form of openness no free Capital free + + align:start position:0% + + + + align:start position:0% + +free Factor mobility in this part of the + + align:start position:0% +free Factor mobility in this part of the + + + align:start position:0% +free Factor mobility in this part of the +course we're not going to talk about + + align:start position:0% +course we're not going to talk about + + + align:start position:0% +course we're not going to talk about +this okay we're going to just we're + + align:start position:0% +this okay we're going to just we're + + + align:start position:0% +this okay we're going to just we're +going to focus in the on these + + align:start position:0% +going to focus in the on these + + + align:start position:0% +going to focus in the on these +two the first we're going to look at is + + align:start position:0% +two the first we're going to look at is + + + align:start position:0% +two the first we're going to look at is +going to be a model of the Goods Market + + align:start position:0% +going to be a model of the Goods Market + + + align:start position:0% +going to be a model of the Goods Market +and that's going to be very much H like + + align:start position:0% +and that's going to be very much H like + + + align:start position:0% +and that's going to be very much H like +the islm but with an open economy and + + align:start position:0% +the islm but with an open economy and + + + align:start position:0% +the islm but with an open economy and +then we're going to bring in interest + + align:start position:0% +then we're going to bring in interest + + + align:start position:0% +then we're going to bring in interest +rate but now on you which is what + + align:start position:0% +rate but now on you which is what + + + align:start position:0% +rate but now on you which is what +remember what we did in the closed + + align:start position:0% +remember what we did in the closed + + + align:start position:0% +remember what we did in the closed +economy first we look at the Goods + + align:start position:0% +economy first we look at the Goods + + + align:start position:0% +economy first we look at the Goods +Market then we look at interest rate + + align:start position:0% +Market then we look at interest rate + + + align:start position:0% +Market then we look at interest rate +determination that was our LM and then + + align:start position:0% +determination that was our LM and then + + + align:start position:0% +determination that was our LM and then +we put the things together we came up + + align:start position:0% +we put the things together we came up + + + align:start position:0% +we put the things together we came up +with slm here the tricky thing is that + + align:start position:0% +with slm here the tricky thing is that + + + align:start position:0% +with slm here the tricky thing is that +there's not only one interest rate there + + align:start position:0% +there's not only one interest rate there + + + align:start position:0% +there's not only one interest rate there +are really two you have to decide + + align:start position:0% +are really two you have to decide + + + align:start position:0% +are really two you have to decide +between the domestic and foreign + + align:start position:0% +between the domestic and foreign + + + align:start position:0% +between the domestic and foreign +interest rate and then there's an + + align:start position:0% +interest rate and then there's an + + + align:start position:0% +interest rate and then there's an +exchange rate in between which will also + + align:start position:0% +exchange rate in between which will also + + + align:start position:0% +exchange rate in between which will also +affect so that's the reason it's going + + align:start position:0% +affect so that's the reason it's going + + + align:start position:0% +affect so that's the reason it's going +to get a little more complicated because + + align:start position:0% +to get a little more complicated because + + + align:start position:0% +to get a little more complicated because +you're going to be having two different + + align:start position:0% +you're going to be having two different + + + align:start position:0% +you're going to be having two different +prices two different Goods you can buy + + align:start position:0% +prices two different Goods you can buy + + + align:start position:0% +prices two different Goods you can buy +you can going to have also two different + + align:start position:0% +you can going to have also two different + + + align:start position:0% +you can going to have also two different +assets you can buy okay and the effects + + align:start position:0% +assets you can buy okay and the effects + + + align:start position:0% +assets you can buy okay and the effects +is going to affect all those things if + + align:start position:0% +is going to affect all those things if + + + align:start position:0% +is going to affect all those things if +when whenever I say FS I mean thechange + + align:start position:0% +when whenever I say FS I mean thechange + + + align:start position:0% +when whenever I say FS I mean thechange +rate + + align:start position:0% +rate + + + align:start position:0% +rate +okay forign exchange that's the reason + + align:start position:0% +okay forign exchange that's the reason + + + align:start position:0% +okay forign exchange that's the reason +sometimes called + + align:start position:0% +sometimes called + + + align:start position:0% +sometimes called +FX now one thing that happens er er is + + align:start position:0% +FX now one thing that happens er er is + + + align:start position:0% +FX now one thing that happens er er is +that because economies are so integrated + + align:start position:0% +that because economies are so integrated + + + align:start position:0% +that because economies are so integrated +in in goods and financial markets is + + align:start position:0% +in in goods and financial markets is + + + align:start position:0% +in in goods and financial markets is +that bus business Cycles tend to be + + align:start position:0% +that bus business Cycles tend to be + + + align:start position:0% +that bus business Cycles tend to be +especially large one large large ones + + align:start position:0% +especially large one large large ones + + + align:start position:0% +especially large one large large ones +tend to be very synchronized around the + + align:start position:0% +tend to be very synchronized around the + + + align:start position:0% +tend to be very synchronized around the +world you see here Emerging + + align:start position:0% + + + + align:start position:0% + +Markets sorry yeah this is the world + + align:start position:0% +Markets sorry yeah this is the world + + + align:start position:0% +Markets sorry yeah this is the world +that's that's emerging markets and + + align:start position:0% +that's that's emerging markets and + + + align:start position:0% +that's that's emerging markets and +that's advanced + + align:start position:0% +that's advanced + + + align:start position:0% +that's advanced +economies you can see the kind of things + + align:start position:0% +economies you can see the kind of things + + + align:start position:0% +economies you can see the kind of things +we discuss in the growth section which + + align:start position:0% +we discuss in the growth section which + + + align:start position:0% +we discuss in the growth section which +is these countries tend to grow faster + + align:start position:0% +is these countries tend to grow faster + + + align:start position:0% +is these countries tend to grow faster +than these countries because they're + + align:start position:0% +than these countries because they're + + + align:start position:0% +than these countries because they're +catching up okay that's the reason + + align:start position:0% +catching up okay that's the reason + + + align:start position:0% +catching up okay that's the reason +they're called emerging you know H but + + align:start position:0% +they're called emerging you know H but + + + align:start position:0% +they're called emerging you know H but +at the level of business cycle they're + + align:start position:0% +at the level of business cycle they're + + + align:start position:0% +at the level of business cycle they're +very synchronized I mean the 2008 2009 + + align:start position:0% +very synchronized I mean the 2008 2009 + + + align:start position:0% +very synchronized I mean the 2008 2009 +recession was a recession + + align:start position:0% +recession was a recession + + + align:start position:0% +recession was a recession +globally this one doesn't have covid but + + align:start position:0% +globally this one doesn't have covid but + + + align:start position:0% +globally this one doesn't have covid but +but well Co naturally was very + + align:start position:0% +but well Co naturally was very + + + align:start position:0% +but well Co naturally was very +synchronized around the world but big + + align:start position:0% +synchronized around the world but big + + + align:start position:0% +synchronized around the world but big +the the point I'm making here is that + + align:start position:0% +the the point I'm making here is that + + + align:start position:0% +the the point I'm making here is that +once you're very integrated to the rest + + align:start position:0% +once you're very integrated to the rest + + + align:start position:0% +once you're very integrated to the rest +of the world you're Al exposed to a new + + align:start position:0% +of the world you're Al exposed to a new + + + align:start position:0% +of the world you're Al exposed to a new +source of shocks it may help you in many + + align:start position:0% +source of shocks it may help you in many + + + align:start position:0% +source of shocks it may help you in many +instances but you're also exposed to + + align:start position:0% +instances but you're also exposed to + + + align:start position:0% +instances but you're also exposed to +things that come + + align:start position:0% +things that come + + + align:start position:0% +things that come +from the rest of the world and the + + align:start position:0% +from the rest of the world and the + + + align:start position:0% +from the rest of the world and the +evidence is that business Cycles are + + align:start position:0% +evidence is that business Cycles are + + + align:start position:0% +evidence is that business Cycles are +very synchronized it's very difficult + + align:start position:0% +very synchronized it's very difficult + + + align:start position:0% +very synchronized it's very difficult +for the rest of the world to be immune + + align:start position:0% +for the rest of the world to be immune + + + align:start position:0% +for the rest of the world to be immune +to us recession for example it's very + + align:start position:0% +to us recession for example it's very + + + align:start position:0% +to us recession for example it's very +easy for the US to be immune to an + + align:start position:0% +easy for the US to be immune to an + + + align:start position:0% +easy for the US to be immune to an +Argentinian recession that's that's a + + align:start position:0% +Argentinian recession that's that's a + + + align:start position:0% +Argentinian recession that's that's a +different story but but but when things + + align:start position:0% +different story but but but when things + + + align:start position:0% +different story but but but when things +are large invol the large economies + + align:start position:0% +are large invol the large economies + + + align:start position:0% +are large invol the large economies +typically that will leak into the rest + + align:start position:0% +typically that will leak into the rest + + + align:start position:0% +typically that will leak into the rest +of the world China has sort of changed a + + align:start position:0% +of the world China has sort of changed a + + + align:start position:0% +of the world China has sort of changed a +little bit the composition used to be + + align:start position:0% +little bit the composition used to be + + + align:start position:0% +little bit the composition used to be +the case that that was always the case + + align:start position:0% +the case that that was always the case + + + align:start position:0% +the case that that was always the case +the if the us sankk then everyone sank + + align:start position:0% +the if the us sankk then everyone sank + + + align:start position:0% +the if the us sankk then everyone sank +and and and and the and now you have + + align:start position:0% +and and and and the and now you have + + + align:start position:0% +and and and and the and now you have +China which stabilizes it's a difference + + align:start position:0% +China which stabilizes it's a difference + + + align:start position:0% +China which stabilizes it's a difference +it's not completely + + align:start position:0% +it's not completely + + + align:start position:0% +it's not completely +correlated with with the US and so that + + align:start position:0% +correlated with with the US and so that + + + align:start position:0% +correlated with with the US and so that +has been stabilizing actually for many + + align:start position:0% +has been stabilizing actually for many + + + align:start position:0% +has been stabilizing actually for many +especially commodity producing economies + + align:start position:0% +especially commodity producing economies + + + align:start position:0% +especially commodity producing economies +and so on but it's still the case big + + align:start position:0% +and so on but it's still the case big + + + align:start position:0% +and so on but it's still the case big +mess is a big mess everywhere if the + + align:start position:0% +mess is a big mess everywhere if the + + + align:start position:0% +mess is a big mess everywhere if the +economies were close there would be no + + align:start position:0% +economies were close there would be no + + + align:start position:0% +economies were close there would be no +reason unless you have some saw you know + + align:start position:0% +reason unless you have some saw you know + + + align:start position:0% +reason unless you have some saw you know +shock covid even if the economies were + + align:start position:0% +shock covid even if the economies were + + + align:start position:0% +shock covid even if the economies were +completely closed would have been a mess + + align:start position:0% +completely closed would have been a mess + + + align:start position:0% +completely closed would have been a mess +because you know it's as long as the + + align:start position:0% +because you know it's as long as the + + + align:start position:0% +because you know it's as long as the +virus spread then it's a mess regardless + + align:start position:0% +virus spread then it's a mess regardless + + + align:start position:0% +virus spread then it's a mess regardless +but that's not the case here this + + align:start position:0% +but that's not the case here this + + + align:start position:0% +but that's not the case here this +recession was caused by a financial + + align:start position:0% +recession was caused by a financial + + + align:start position:0% +recession was caused by a financial +shock in the + + align:start position:0% +shock in the + + + align:start position:0% +shock in the +US okay and still the whole econ the the + + align:start position:0% +US okay and still the whole econ the the + + + align:start position:0% +US okay and still the whole econ the the +global economy as a whole suffer a lot + + align:start position:0% +global economy as a whole suffer a lot + + + align:start position:0% +global economy as a whole suffer a lot +so Things become very synchronized + + align:start position:0% +so Things become very synchronized + + + align:start position:0% +so Things become very synchronized +because of + + align:start position:0% +because of + + + align:start position:0% +because of +that another thing that has been + + align:start position:0% +that another thing that has been + + + align:start position:0% +that another thing that has been +happening is that + + align:start position:0% +happening is that + + + align:start position:0% +happening is that +everywhere again still we shall see + + align:start position:0% +everywhere again still we shall see + + + align:start position:0% +everywhere again still we shall see +where we end up after this covid things + + align:start position:0% +where we end up after this covid things + + + align:start position:0% +where we end up after this covid things +there was a slight reversion of that but + + align:start position:0% +there was a slight reversion of that but + + + align:start position:0% +there was a slight reversion of that but +everywhere even the US which one of the + + align:start position:0% +everywhere even the US which one of the + + + align:start position:0% +everywhere even the US which one of the +closest economies in the world one of + + align:start position:0% +closest economies in the world one of + + + align:start position:0% +closest economies in the world one of +the closest of the significant economies + + align:start position:0% +the closest of the significant economies + + + align:start position:0% +the closest of the significant economies +ER there has been a sort of there was a + + align:start position:0% +ER there has been a sort of there was a + + + align:start position:0% +ER there has been a sort of there was a +steady Trend rise towards higher + + align:start position:0% +steady Trend rise towards higher + + + align:start position:0% +steady Trend rise towards higher +integration to the rest of the world + + align:start position:0% +integration to the rest of the world + + + align:start position:0% +integration to the rest of the world +okay and the same is happening in + + align:start position:0% +okay and the same is happening in + + + align:start position:0% +okay and the same is happening in +financial markets it's just an order of + + align:start position:0% +financial markets it's just an order of + + + align:start position:0% +financial markets it's just an order of +magnitude larger but but you see here in + + align:start position:0% +magnitude larger but but you see here in + + + align:start position:0% +magnitude larger but but you see here in +the US you see that imports and exports + + align:start position:0% +the US you see that imports and exports + + + align:start position:0% +the US you see that imports and exports +as a share of GDP they were both Rising + + align:start position:0% +as a share of GDP they were both Rising + + + align:start position:0% +as a share of GDP they were both Rising +ing over time here shows you what I + + align:start position:0% +ing over time here shows you what I + + + align:start position:0% +ing over time here shows you what I +showed you before which is the deficit + + align:start position:0% +showed you before which is the deficit + + + align:start position:0% +showed you before which is the deficit +chronic deficit that the US has had but + + align:start position:0% +chronic deficit that the US has had but + + + align:start position:0% +chronic deficit that the US has had but +still even exports have been rising for + + align:start position:0% +still even exports have been rising for + + + align:start position:0% +still even exports have been rising for +a while + + align:start position:0% +a while + + + align:start position:0% +a while +now this number here you know that about + + align:start position:0% +now this number here you know that about + + + align:start position:0% +now this number here you know that about +the 20% of the US produced Goods 15% of + + align:start position:0% +the 20% of the US produced Goods 15% of + + + align:start position:0% +the 20% of the US produced Goods 15% of +GDP the US has about 15% of of of GDP in + + align:start position:0% +GDP the US has about 15% of of of GDP in + + + align:start position:0% +GDP the US has about 15% of of of GDP in +Imports and in exports some people use + + align:start position:0% +Imports and in exports some people use + + + align:start position:0% +Imports and in exports some people use +that the sum for example of Imports plus + + align:start position:0% +that the sum for example of Imports plus + + + align:start position:0% +that the sum for example of Imports plus +exports over GDP as a measure of + + align:start position:0% +exports over GDP as a measure of + + + align:start position:0% +exports over GDP as a measure of +openness how open is an economy and it's + + align:start position:0% +openness how open is an economy and it's + + + align:start position:0% +openness how open is an economy and it's +okay for comparisons but it's clearly + + align:start position:0% +okay for comparisons but it's clearly + + + align:start position:0% +okay for comparisons but it's clearly +underestimate how open economies really + + align:start position:0% +underestimate how open economies really + + + align:start position:0% +underestimate how open economies really +are I mean many of the goods that are + + align:start position:0% +are I mean many of the goods that are + + + align:start position:0% +are I mean many of the goods that are +considered that that the US does not + + align:start position:0% +considered that that the US does not + + + align:start position:0% +considered that that the US does not +import are produced domestically so they + + align:start position:0% +import are produced domestically so they + + + align:start position:0% +import are produced domestically so they +don't count as part of imports or + + align:start position:0% +don't count as part of imports or + + + align:start position:0% +don't count as part of imports or +anything their price is really + + align:start position:0% +anything their price is really + + + align:start position:0% +anything their price is really +determined by International + + align:start position:0% +determined by International + + + align:start position:0% +determined by International +competition okay the price of a of a + + align:start position:0% +competition okay the price of a of a + + + align:start position:0% +competition okay the price of a of a +Ford is very different with foreign + + align:start position:0% +Ford is very different with foreign + + + align:start position:0% +Ford is very different with foreign +compe I that not so we don't count the + + align:start position:0% +compe I that not so we don't count the + + + align:start position:0% +compe I that not so we don't count the +fors produced here as Imports or + + align:start position:0% +fors produced here as Imports or + + + align:start position:0% +fors produced here as Imports or +anything or and if would be part of the + + align:start position:0% +anything or and if would be part of the + + + align:start position:0% +anything or and if would be part of the +nontradable not tradeable it wouldn't + + align:start position:0% +nontradable not tradeable it wouldn't + + + align:start position:0% +nontradable not tradeable it wouldn't +part of this measure of openness but + + align:start position:0% +part of this measure of openness but + + + align:start position:0% +part of this measure of openness but +it's clear that the price and even the + + align:start position:0% +it's clear that the price and even the + + + align:start position:0% +it's clear that the price and even the +quality is being affected by exposure to + + align:start position:0% +quality is being affected by exposure to + + + align:start position:0% +quality is being affected by exposure to +International competition okay so there + + align:start position:0% +International competition okay so there + + + align:start position:0% +International competition okay so there +are very few sectors that are not really + + align:start position:0% +are very few sectors that are not really + + + align:start position:0% +are very few sectors that are not really +exposed to International competitions + + align:start position:0% +exposed to International competitions + + + align:start position:0% +exposed to International competitions +yeah haircuts they're not I mean you + + align:start position:0% +yeah haircuts they're not I mean you + + + align:start position:0% +yeah haircuts they're not I mean you +know you're not going to unless you + + align:start position:0% +know you're not going to unless you + + + align:start position:0% +know you're not going to unless you +leave sort of at + + align:start position:0% +leave sort of at + + + align:start position:0% +leave sort of at +some country you know County at the + + align:start position:0% +some country you know County at the + + + align:start position:0% +some country you know County at the +border of with Canada and there is a + + align:start position:0% +border of with Canada and there is a + + + align:start position:0% +border of with Canada and there is a +town right on the side that that's + + align:start position:0% +town right on the side that that's + + + align:start position:0% +town right on the side that that's +that's that's not going to happen + + align:start position:0% +that's that's not going to happen + + + align:start position:0% +that's that's not going to happen +but okay so trend is upward and and and + + align:start position:0% +but okay so trend is upward and and and + + + align:start position:0% +but okay so trend is upward and and and +uh even more so than than those numbers + + align:start position:0% +uh even more so than than those numbers + + + align:start position:0% +uh even more so than than those numbers +suggest if you look across the world and + + align:start position:0% +suggest if you look across the world and + + + align:start position:0% +suggest if you look across the world and +here is what I show you before is what I + + align:start position:0% +here is what I show you before is what I + + + align:start position:0% +here is what I show you before is what I +said before is the US + + align:start position:0% +said before is the US + + + align:start position:0% +said before is the US +actually it's is certainly look very + + align:start position:0% +actually it's is certainly look very + + + align:start position:0% +actually it's is certainly look very +close relative to others if you look at + + align:start position:0% +close relative to others if you look at + + + align:start position:0% +close relative to others if you look at +across large + + align:start position:0% +across large + + + align:start position:0% +across large +economies Japan which is also a very + + align:start position:0% +economies Japan which is also a very + + + align:start position:0% +economies Japan which is also a very +close economy for a variety of reasons + + align:start position:0% +close economy for a variety of reasons + + + align:start position:0% +close economy for a variety of reasons +is still more open than the US UK little + + align:start position:0% +is still more open than the US UK little + + + align:start position:0% +is still more open than the US UK little +Chile here but you know one thing that + + align:start position:0% +Chile here but you know one thing that + + + align:start position:0% +Chile here but you know one thing that +this shows this Dimension here shows is + + align:start position:0% +this shows this Dimension here shows is + + + align:start position:0% +this shows this Dimension here shows is +that the smaller you are the more open + + align:start position:0% +that the smaller you are the more open + + + align:start position:0% +that the smaller you are the more open +you're likely to be and it makes sense + + align:start position:0% +you're likely to be and it makes sense + + + align:start position:0% +you're likely to be and it makes sense +it's harder to produce all the goods if + + align:start position:0% +it's harder to produce all the goods if + + + align:start position:0% +it's harder to produce all the goods if +you have you know a small + + align:start position:0% +you have you know a small + + + align:start position:0% +you have you know a small +country and and and so so so that's + + align:start position:0% +country and and and so so so that's + + + align:start position:0% +country and and and so so so that's +that's a pattern the smaller you are + + align:start position:0% +that's a pattern the smaller you are + + + align:start position:0% +that's a pattern the smaller you are +controlling for a variety of + + align:start position:0% +controlling for a variety of + + + align:start position:0% +controlling for a variety of +factors ER you tend to be more open you + + align:start position:0% +factors ER you tend to be more open you + + + align:start position:0% +factors ER you tend to be more open you +need to Import and Export more import + + align:start position:0% +need to Import and Export more import + + + align:start position:0% +need to Import and Export more import +more in particular uh now that pattern + + align:start position:0% +more in particular uh now that pattern + + + align:start position:0% +more in particular uh now that pattern +is disrupted when you look in this + + align:start position:0% +is disrupted when you look in this + + + align:start position:0% +is disrupted when you look in this +direction no so this all these + + align:start position:0% +direction no so this all these + + + align:start position:0% +direction no so this all these +countries ER which are clearly much + + align:start position:0% +countries ER which are clearly much + + + align:start position:0% +countries ER which are clearly much +larger than Chile in terms of GDP and on + + align:start position:0% +larger than Chile in terms of GDP and on + + + align:start position:0% +larger than Chile in terms of GDP and on +ER have very high export ratios why do + + align:start position:0% +ER have very high export ratios why do + + + align:start position:0% +ER have very high export ratios why do +you think that's the + + align:start position:0% + + + + align:start position:0% + +case exactly they're in Europe so so you + + align:start position:0% +case exactly they're in Europe so so you + + + align:start position:0% +case exactly they're in Europe so so you +know this Europe is very special Europe + + align:start position:0% +know this Europe is very special Europe + + + align:start position:0% +know this Europe is very special Europe +as a whole is as close as the US so if + + align:start position:0% +as a whole is as close as the US so if + + + align:start position:0% +as a whole is as close as the US so if +you look at the whole area together but + + align:start position:0% +you look at the whole area together but + + + align:start position:0% +you look at the whole area together but +but there is lots of intra Europe + + align:start position:0% +but there is lots of intra Europe + + + align:start position:0% +but there is lots of intra Europe +exports and imports especially in the + + align:start position:0% +exports and imports especially in the + + + align:start position:0% +exports and imports especially in the +Euro Zone I mean you have lots of things + + align:start position:0% +Euro Zone I mean you have lots of things + + + align:start position:0% +Euro Zone I mean you have lots of things +you have the same currency you just you + + align:start position:0% +you have the same currency you just you + + + align:start position:0% +you have the same currency you just you +know it's it's right next door so so so + + align:start position:0% +know it's it's right next door so so so + + + align:start position:0% +know it's it's right next door so so so +they're very open but they're very open + + align:start position:0% +they're very open but they're very open + + + align:start position:0% +they're very open but they're very open +within Europe not so much with the rest + + align:start position:0% +within Europe not so much with the rest + + + align:start position:0% +within Europe not so much with the rest +of the + + align:start position:0% +of the + + + align:start position:0% +of the +world but this does a differ shate intra + + align:start position:0% +world but this does a differ shate intra + + + align:start position:0% +world but this does a differ shate intra +Europe exports and imports versus total + + align:start position:0% +Europe exports and imports versus total + + + align:start position:0% +Europe exports and imports versus total +and that's the reason you see these + + align:start position:0% +and that's the reason you see these + + + align:start position:0% +and that's the reason you see these +numbers are very very large but even + + align:start position:0% +numbers are very very large but even + + + align:start position:0% +numbers are very very large but even +here within here you see that the + + align:start position:0% +here within here you see that the + + + align:start position:0% +here within here you see that the +smaller countries tend to be very open + + align:start position:0% +smaller countries tend to be very open + + + align:start position:0% +smaller countries tend to be very open +much more open than than than bigger + + align:start position:0% +much more open than than than bigger + + + align:start position:0% +much more open than than than bigger +countries + + align:start position:0% +countries + + + align:start position:0% +countries +okay + + align:start position:0% + + + + align:start position:0% + +good so H as as I said so + + align:start position:0% +good so H as as I said so + + + align:start position:0% +good so H as as I said so +terminology um this picture looks very + + align:start position:0% +terminology um this picture looks very + + + align:start position:0% +terminology um this picture looks very +similar to the picture I show you + + align:start position:0% +similar to the picture I show you + + + align:start position:0% +similar to the picture I show you +earlier on but it's not there it was a + + align:start position:0% +earlier on but it's not there it was a + + + align:start position:0% +earlier on but it's not there it was a +trade weighted H dollar and here is just + + align:start position:0% +trade weighted H dollar and here is just + + + align:start position:0% +trade weighted H dollar and here is just +one particular bilateral exchange rate + + align:start position:0% +one particular bilateral exchange rate + + + align:start position:0% +one particular bilateral exchange rate +which is the dollar yen exchange rate + + align:start position:0% +which is the dollar yen exchange rate + + + align:start position:0% +which is the dollar yen exchange rate +what happens is is when the dollar + + align:start position:0% +what happens is is when the dollar + + + align:start position:0% +what happens is is when the dollar +appreciates typically appreciates + + align:start position:0% +appreciates typically appreciates + + + align:start position:0% +appreciates typically appreciates +against everything and so on that's the + + align:start position:0% +against everything and so on that's the + + + align:start position:0% +against everything and so on that's the +reason the pictures look very similar + + align:start position:0% +reason the pictures look very similar + + + align:start position:0% +reason the pictures look very similar +but this was pretty dramatic you know + + align:start position:0% +but this was pretty dramatic you know + + + align:start position:0% +but this was pretty dramatic you know +there was a very sharp appreciation of + + align:start position:0% +there was a very sharp appreciation of + + + align:start position:0% +there was a very sharp appreciation of +the of the dollar of well strike what I + + align:start position:0% +the of the dollar of well strike what I + + + align:start position:0% +the of the dollar of well strike what I +said I'm so anyways this is the pattern + + align:start position:0% +said I'm so anyways this is the pattern + + + align:start position:0% +said I'm so anyways this is the pattern +of the number of yens per dollars + + align:start position:0% +of the number of yens per dollars + + + align:start position:0% +of the number of yens per dollars +meaning meaning that's we decided that + + align:start position:0% +meaning meaning that's we decided that + + + align:start position:0% +meaning meaning that's we decided that +that's the way we're going to find the + + align:start position:0% +that's the way we're going to find the + + + align:start position:0% +that's the way we're going to find the +exchange this the price of the domestic + + align:start position:0% +exchange this the price of the domestic + + + align:start position:0% +exchange this the price of the domestic +currency in terms of foreign currency so + + align:start position:0% +currency in terms of foreign currency so + + + align:start position:0% +currency in terms of foreign currency so +the price of the US dollar goes up up + + align:start position:0% +the price of the US dollar goes up up + + + align:start position:0% +the price of the US dollar goes up up +when they pay you more yens per dollar + + align:start position:0% +when they pay you more yens per dollar + + + align:start position:0% +when they pay you more yens per dollar +okay and and it went up very rapidly + + align:start position:0% +okay and and it went up very rapidly + + + align:start position:0% +okay and and it went up very rapidly +from close to 100 to 150 that was + + align:start position:0% +from close to 100 to 150 that was + + + align:start position:0% +from close to 100 to 150 that was +massive there were massive interventions + + align:start position:0% +massive there were massive interventions + + + align:start position:0% +massive there were massive interventions +here because it was clear that this was + + align:start position:0% +here because it was clear that this was + + + align:start position:0% +here because it was clear that this was +getting totally out of hand but but uh + + align:start position:0% +getting totally out of hand but but uh + + + align:start position:0% +getting totally out of hand but but uh +but any so that was okay and we + + align:start position:0% +but any so that was okay and we + + + align:start position:0% +but any so that was okay and we +say in this case so when a currency + + align:start position:0% +say in this case so when a currency + + + align:start position:0% +say in this case so when a currency +gains in value we call that in terms of + + align:start position:0% +gains in value we call that in terms of + + + align:start position:0% +gains in value we call that in terms of +other currencies there's no sense of a + + align:start position:0% +other currencies there's no sense of a + + + align:start position:0% +other currencies there's no sense of a +currency gaining value in terms of + + align:start position:0% +currency gaining value in terms of + + + align:start position:0% +currency gaining value in terms of +nothing it has to be in terms of other + + align:start position:0% +nothing it has to be in terms of other + + + align:start position:0% +nothing it has to be in terms of other +currency that's what an exchange itate + + align:start position:0% +currency that's what an exchange itate + + + align:start position:0% +currency that's what an exchange itate +is we say that the currency is + + align:start position:0% +is we say that the currency is + + + align:start position:0% +is we say that the currency is +appreciating okay so in this case is the + + align:start position:0% +appreciating okay so in this case is the + + + align:start position:0% +appreciating okay so in this case is the +nominal exchange rate so it's dollars + + align:start position:0% +nominal exchange rate so it's dollars + + + align:start position:0% +nominal exchange rate so it's dollars +per dollars when the + + align:start position:0% +per dollars when the + + + align:start position:0% +per dollars when the +dollar when the dollar is going up here + + align:start position:0% +dollar when the dollar is going up here + + + align:start position:0% +dollar when the dollar is going up here +we say the dollar is appreciating + + align:start position:0% +we say the dollar is appreciating + + + align:start position:0% +we say the dollar is appreciating +relative to the Japanese Yen okay that + + align:start position:0% +relative to the Japanese Yen okay that + + + align:start position:0% +relative to the Japanese Yen okay that +means the dollar is becoming more + + align:start position:0% +means the dollar is becoming more + + + align:start position:0% +means the dollar is becoming more +expensive they have to give you more + + align:start position:0% +expensive they have to give you more + + + align:start position:0% +expensive they have to give you more +yens per dollar you can look at it from + + align:start position:0% +yens per dollar you can look at it from + + + align:start position:0% +yens per dollar you can look at it from +the point of view of Japan and then the + + align:start position:0% +the point of view of Japan and then the + + + align:start position:0% +the point of view of Japan and then the +picture would look the other way around + + align:start position:0% +picture would look the other way around + + + align:start position:0% +picture would look the other way around +and it says in this same picture I know + + align:start position:0% +and it says in this same picture I know + + + align:start position:0% +and it says in this same picture I know +that the Japanese yen is + + align:start position:0% +that the Japanese yen is + + + align:start position:0% +that the Japanese yen is +depreciating relative to the US dollar + + align:start position:0% +depreciating relative to the US dollar + + + align:start position:0% +depreciating relative to the US dollar +okay so depreciation is when your + + align:start position:0% +okay so depreciation is when your + + + align:start position:0% +okay so depreciation is when your +currency loses value appreciation is + + align:start position:0% +currency loses value appreciation is + + + align:start position:0% +currency loses value appreciation is +when your currency gains + + align:start position:0% + + + + align:start position:0% + +value a k i mean if I tell you unless + + align:start position:0% +value a k i mean if I tell you unless + + + align:start position:0% +value a k i mean if I tell you unless +you sort of more or less knows the + + align:start position:0% +you sort of more or less knows the + + + align:start position:0% +you sort of more or less knows the +prices in the different places if I tell + + align:start position:0% +prices in the different places if I tell + + + align:start position:0% +prices in the different places if I tell +you that that that the Japanese + + align:start position:0% +you that that that the Japanese + + + align:start position:0% +you that that that the Japanese +ER the US buys 1030 + + align:start position:0% +ER the US buys 1030 + + + align:start position:0% +ER the US buys 1030 +Japanese Yen you can tell me and then I + + align:start position:0% +Japanese Yen you can tell me and then I + + + align:start position:0% +Japanese Yen you can tell me and then I +ask you where would you like to buy your + + align:start position:0% +ask you where would you like to buy your + + + align:start position:0% +ask you where would you like to buy your +car and assume that the car is the same + + align:start position:0% +car and assume that the car is the same + + + align:start position:0% +car and assume that the car is the same +quality no transport cost and so on and + + align:start position:0% +quality no transport cost and so on and + + + align:start position:0% +quality no transport cost and so on and +I tell you look the Japanese yen is give + + align:start position:0% +I tell you look the Japanese yen is give + + + align:start position:0% +I tell you look the Japanese yen is give +you you you for each dollar you get 120 + + align:start position:0% +you you you for each dollar you get 120 + + + align:start position:0% +you you you for each dollar you get 120 +130 Japanese Y where do you want to buy + + align:start position:0% +130 Japanese Y where do you want to buy + + + align:start position:0% +130 Japanese Y where do you want to buy +your + + align:start position:0% + + + + align:start position:0% + +cars that's the right answer you have no + + align:start position:0% +cars that's the right answer you have no + + + align:start position:0% +cars that's the right answer you have no +clue that doesn't tell you anything know + + align:start position:0% +clue that doesn't tell you anything know + + + align:start position:0% +clue that doesn't tell you anything know +it tells you the the the nominal + + align:start position:0% +it tells you the the the nominal + + + align:start position:0% +it tells you the the the nominal +exchanger tells you the relative value + + align:start position:0% +exchanger tells you the relative value + + + align:start position:0% +exchanger tells you the relative value +of of currencies + + align:start position:0% +of of currencies + + + align:start position:0% +of of currencies +but to make the decision of where you + + align:start position:0% +but to make the decision of where you + + + align:start position:0% +but to make the decision of where you +buy your car you need to know which car + + align:start position:0% +buy your car you need to know which car + + + align:start position:0% +buy your car you need to know which car +is more expensive and that's for that's + + align:start position:0% +is more expensive and that's for that's + + + align:start position:0% +is more expensive and that's for that's +not enough to know the the the the the + + align:start position:0% +not enough to know the the the the the + + + align:start position:0% +not enough to know the the the the the +the exchange the nominal exchange you + + align:start position:0% +the exchange the nominal exchange you + + + align:start position:0% +the exchange the nominal exchange you +need to know what is the price of the + + align:start position:0% +need to know what is the price of the + + + align:start position:0% +need to know what is the price of the +car in each place in its own currency + + align:start position:0% +car in each place in its own currency + + + align:start position:0% +car in each place in its own currency +and then I'm going to use exchange rate + + align:start position:0% +and then I'm going to use exchange rate + + + align:start position:0% +and then I'm going to use exchange rate +to translate them into some common + + align:start position:0% +to translate them into some common + + + align:start position:0% +to translate them into some common +currency suppose I tell you now that H + + align:start position:0% +currency suppose I tell you now that H + + + align:start position:0% +currency suppose I tell you now that H +the the price of of of the they do the + + align:start position:0% +the the price of of of the they do the + + + align:start position:0% +the the price of of of the they do the +opposite experiment they say look the + + align:start position:0% +opposite experiment they say look the + + + align:start position:0% +opposite experiment they say look the +price of a of a of a the same car in + + align:start position:0% +price of a of a of a the same car in + + + align:start position:0% +price of a of a of a the same car in +Japan + + align:start position:0% +Japan + + + align:start position:0% +Japan +is um + + align:start position:0% +is um + + + align:start position:0% +is um +150,000 + + align:start position:0% +150,000 + + + align:start position:0% +150,000 +Yen well there you all have to lots of + + align:start position:0% +Yen well there you all have to lots of + + + align:start position:0% +Yen well there you all have to lots of +zeros + + align:start position:0% +zeros + + + align:start position:0% +zeros +but 150,000 Y and and in the US is500 + + align:start position:0% +but 150,000 Y and and in the US is500 + + + align:start position:0% +but 150,000 Y and and in the US is500 +this a used car something + + align:start position:0% +this a used car something + + + align:start position:0% +this a used car something +$1,500 and and then I ask you a question + + align:start position:0% +$1,500 and and then I ask you a question + + + align:start position:0% +$1,500 and and then I ask you a question +where do you want to buy your + + align:start position:0% +where do you want to buy your + + + align:start position:0% +where do you want to buy your +car you can't answer either because you + + align:start position:0% +car you can't answer either because you + + + align:start position:0% +car you can't answer either because you +don't know how to compare unless I give + + align:start position:0% +don't know how to compare unless I give + + + align:start position:0% +don't know how to compare unless I give +you the nominal exchanges as well you + + align:start position:0% +you the nominal exchanges as well you + + + align:start position:0% +you the nominal exchanges as well you +don't know how to compare those 150,000 + + align:start position:0% +don't know how to compare those 150,000 + + + align:start position:0% +don't know how to compare those 150,000 +yens for versus the 50 $100 so you need + + align:start position:0% +yens for versus the 50 $100 so you need + + + align:start position:0% +yens for versus the 50 $100 so you need +both and that concept that captures both + + align:start position:0% +both and that concept that captures both + + + align:start position:0% +both and that concept that captures both +is what is called the real exchange rate + + align:start position:0% +is what is called the real exchange rate + + + align:start position:0% +is what is called the real exchange rate +the real exchange is design for that to + + align:start position:0% +the real exchange is design for that to + + + align:start position:0% +the real exchange is design for that to +capture where you're going to do your + + align:start position:0% +capture where you're going to do your + + + align:start position:0% +capture where you're going to do your +imports and exports okay and it's a + + align:start position:0% +imports and exports okay and it's a + + + align:start position:0% +imports and exports okay and it's a +relative pricing of two not currencies + + align:start position:0% +relative pricing of two not currencies + + + align:start position:0% +relative pricing of two not currencies +but + + align:start position:0% +but + + + align:start position:0% +but +Goods okay so that's what the real + + align:start position:0% +Goods okay so that's what the real + + + align:start position:0% +Goods okay so that's what the real +exchange is is the price of domestic + + align:start position:0% +exchange is is the price of domestic + + + align:start position:0% +exchange is is the price of domestic +Goods relative to foreign Goods how many + + align:start position:0% +Goods relative to foreign Goods how many + + + align:start position:0% +Goods relative to foreign Goods how many +japanese cars you give me for one car us + + align:start position:0% +japanese cars you give me for one car us + + + align:start position:0% +japanese cars you give me for one car us +car that's a real exchange rate which is + + align:start position:0% +car that's a real exchange rate which is + + + align:start position:0% +car that's a real exchange rate which is +different from the nominal exchange + + align:start position:0% +different from the nominal exchange + + + align:start position:0% +different from the nominal exchange +rate now it's related to the nominal + + align:start position:0% +rate now it's related to the nominal + + + align:start position:0% +rate now it's related to the nominal +exchange rate and it happens that in + + align:start position:0% +exchange rate and it happens that in + + + align:start position:0% +exchange rate and it happens that in +practice a lot of the volatility of that + + align:start position:0% +practice a lot of the volatility of that + + + align:start position:0% +practice a lot of the volatility of that +price is as result of the volatility of + + align:start position:0% +price is as result of the volatility of + + + align:start position:0% +price is as result of the volatility of +the nominal exchange but this let me and + + align:start position:0% +the nominal exchange but this let me and + + + align:start position:0% +the nominal exchange but this let me and +this with this I will stop so let me + + align:start position:0% +this with this I will stop so let me + + + align:start position:0% +this with this I will stop so let me +call Epsilon the real exchange rate and + + align:start position:0% +call Epsilon the real exchange rate and + + + align:start position:0% +call Epsilon the real exchange rate and +let me let me see how we're going to get + + align:start position:0% +let me let me see how we're going to get + + + align:start position:0% +let me let me see how we're going to get +to that expression here so what want to + + align:start position:0% +to that expression here so what want to + + + align:start position:0% +to that expression here so what want to +compare here is the relative value of + + align:start position:0% +compare here is the relative value of + + + align:start position:0% +compare here is the relative value of +two goods because that's what will + + align:start position:0% +two goods because that's what will + + + align:start position:0% +two goods because that's what will +matter for my my consumption decision or + + align:start position:0% +matter for my my consumption decision or + + + align:start position:0% +matter for my my consumption decision or +my purchase decision + + align:start position:0% +my purchase decision + + + align:start position:0% +my purchase decision +so suppose we're talking about this car + + align:start position:0% +so suppose we're talking about this car + + + align:start position:0% +so suppose we're talking about this car +and suppose I know that the price of a + + align:start position:0% +and suppose I know that the price of a + + + align:start position:0% +and suppose I know that the price of a +of of of the car in the US is + + align:start position:0% +of of of the car in the US is + + + align:start position:0% +of of of the car in the US is +p okay and now I want to compare it with + + align:start position:0% +p okay and now I want to compare it with + + + align:start position:0% +p okay and now I want to compare it with +the with well do I buy it here or do I + + align:start position:0% +the with well do I buy it here or do I + + + align:start position:0% +the with well do I buy it here or do I +buy it in Japan for that um I'm going to + + align:start position:0% +buy it in Japan for that um I'm going to + + + align:start position:0% +buy it in Japan for that um I'm going to +have to I I'm going to have to compare + + align:start position:0% +have to I I'm going to have to compare + + + align:start position:0% +have to I I'm going to have to compare +them in the same currency so the first + + align:start position:0% +them in the same currency so the first + + + align:start position:0% +them in the same currency so the first +thing I'm going to do is I'm going to + + align:start position:0% +thing I'm going to do is I'm going to + + + align:start position:0% +thing I'm going to do is I'm going to +translate my US dollar price for to + + align:start position:0% +translate my US dollar price for to + + + align:start position:0% +translate my US dollar price for to +Japanese dollar to to Yen pricing okay + + align:start position:0% +Japanese dollar to to Yen pricing okay + + + align:start position:0% +Japanese dollar to to Yen pricing okay +so say the the the I'm going to have + + align:start position:0% +so say the the the I'm going to have + + + align:start position:0% +so say the the the I'm going to have +simpler numbers than the one there + + align:start position:0% +simpler numbers than the one there + + + align:start position:0% +simpler numbers than the one there +supposed to the car in the US cost + + align:start position:0% +supposed to the car in the US cost + + + align:start position:0% +supposed to the car in the US cost +$10,000 suppose that for each dollar you + + align:start position:0% +$10,000 suppose that for each dollar you + + + align:start position:0% +$10,000 suppose that for each dollar you +get 10 Yen then then $10,000 time 10 + + align:start position:0% +get 10 Yen then then $10,000 time 10 + + + align:start position:0% +get 10 Yen then then $10,000 time 10 +that means it's $ 100,000 Yen so the us + + align:start position:0% +that means it's $ 100,000 Yen so the us + + + align:start position:0% +that means it's $ 100,000 Yen so the us +if I buy the car in the US I pay 100,000 + + align:start position:0% +if I buy the car in the US I pay 100,000 + + + align:start position:0% +if I buy the car in the US I pay 100,000 +Yen and so now ah sorry this was not + + align:start position:0% +Yen and so now ah sorry this was not + + + align:start position:0% +Yen and so now ah sorry this was not +Japan in this example it's the UK well + + align:start position:0% +Japan in this example it's the UK well + + + align:start position:0% +Japan in this example it's the UK well +the same story okay and it's even + + align:start position:0% +the same story okay and it's even + + + align:start position:0% +the same story okay and it's even +simpler ER is say + + align:start position:0% +simpler ER is say + + + align:start position:0% +simpler ER is say +then then the the car in the US cost + + align:start position:0% +then then the the car in the US cost + + + align:start position:0% +then then the the car in the US cost +$10,000 and the The Exchange each dollar + + align:start position:0% +$10,000 and the The Exchange each dollar + + + align:start position:0% +$10,000 and the The Exchange each dollar +buys 80 cents of 80 cents of of pounds + + align:start position:0% +buys 80 cents of 80 cents of of pounds + + + align:start position:0% +buys 80 cents of 80 cents of of pounds +so that means 8,000 pound so the US car + + align:start position:0% +so that means 8,000 pound so the US car + + + align:start position:0% +so that means 8,000 pound so the US car +is is cost + + align:start position:0% +is is cost + + + align:start position:0% +is is cost +8,000 now I compare it with a car in the + + align:start position:0% +8,000 now I compare it with a car in the + + + align:start position:0% +8,000 now I compare it with a car in the +UK say the same car and the ratio of + + align:start position:0% +UK say the same car and the ratio of + + + align:start position:0% +UK say the same car and the ratio of +these two things is what we call the + + align:start position:0% +these two things is what we call the + + + align:start position:0% +these two things is what we call the +real exchange rate so it's the price of + + align:start position:0% +real exchange rate so it's the price of + + + align:start position:0% +real exchange rate so it's the price of +the domestic Good Times the exchange + + align:start position:0% +the domestic Good Times the exchange + + + align:start position:0% +the domestic Good Times the exchange +rate divided by the foreign price and + + align:start position:0% +rate divided by the foreign price and + + + align:start position:0% +rate divided by the foreign price and +that's a real exchange so if the if the + + align:start position:0% +that's a real exchange so if the if the + + + align:start position:0% +that's a real exchange so if the if the +if the price in the of the of the car in + + align:start position:0% +if the price in the of the of the car in + + + align:start position:0% +if the price in the of the of the car in +the UK was $9,000 and I could buy the + + align:start position:0% +the UK was $9,000 and I could buy the + + + align:start position:0% +the UK was $9,000 and I could buy the +car in the US for $8,000 I would + + align:start position:0% +car in the US for $8,000 I would + + + align:start position:0% +car in the US for $8,000 I would +probably buy it in the US in practice + + align:start position:0% +probably buy it in the US in practice + + + align:start position:0% +probably buy it in the US in practice +there are difference between the two car + + align:start position:0% +there are difference between the two car + + + align:start position:0% +there are difference between the two car +on but that tells you that's the kind of + + align:start position:0% +on but that tells you that's the kind of + + + align:start position:0% +on but that tells you that's the kind of +thing that the real exchange means is a + + align:start position:0% +thing that the real exchange means is a + + + align:start position:0% +thing that the real exchange means is a +relative price of goods okay but the way + + align:start position:0% +relative price of goods okay but the way + + + align:start position:0% +relative price of goods okay but the way +to go from that is you have to multiply + + align:start position:0% +to go from that is you have to multiply + + + align:start position:0% +to go from that is you have to multiply +the nominal exchange rate times the + + align:start position:0% +the nominal exchange rate times the + + + align:start position:0% +the nominal exchange rate times the +price because that converts it into the + + align:start position:0% +price because that converts it into the + + + align:start position:0% +price because that converts it into the +same currency as the price and then you + + align:start position:0% +same currency as the price and then you + + + align:start position:0% +same currency as the price and then you +can compare them that's + + align:start position:0% +can compare them that's + + + align:start position:0% +can compare them that's +idea so let let's stop here and we're + + align:start position:0% +idea so let let's stop here and we're + + + align:start position:0% +idea so let let's stop here and we're +going to continue talking about open + + align:start position:0% +going to continue talking about open + + + align:start position:0% +going to continue talking about open +economy next week so next on Wednesday + + align:start position:0% +economy next week so next on Wednesday + + + align:start position:0% +economy next week so next on Wednesday +what I'm going to do is a review of of H + + align:start position:0% +what I'm going to do is a review of of H + + + align:start position:0% +what I'm going to do is a review of of H +ISL MPC and and and growth \ No newline at end of file diff --git a/68XZ_P9MKM8.txt b/68XZ_P9MKM8.txt new file mode 100644 index 0000000000000000000000000000000000000000..037d31a086732f09e5b0d20cafe2fb6f4798f163 --- /dev/null +++ b/68XZ_P9MKM8.txt @@ -0,0 +1,13819 @@ +align:start position:0% + +To participate in this next exercise, + + align:start position:0% +To participate in this next exercise, + + + align:start position:0% +To participate in this next exercise, +you'll have to grab um one of these uh + + align:start position:0% +you'll have to grab um one of these uh + + + align:start position:0% +you'll have to grab um one of these uh +uh index cards that are on the table + + align:start position:0% +uh index cards that are on the table + + + align:start position:0% +uh index cards that are on the table +that correspond to a particular + + align:start position:0% +that correspond to a particular + + + align:start position:0% +that correspond to a particular +technology. It looks like film, radio, + + align:start position:0% +technology. It looks like film, radio, + + + align:start position:0% +technology. It looks like film, radio, +and television are amongst the remaining + + align:start position:0% +and television are amongst the remaining + + + align:start position:0% +and television are amongst the remaining +ones. Um and you'll get in small groups + + align:start position:0% +ones. Um and you'll get in small groups + + + align:start position:0% +ones. Um and you'll get in small groups +um and uh work on those. Here's what I'd + + align:start position:0% +um and uh work on those. Here's what I'd + + + align:start position:0% +um and uh work on those. Here's what I'd +like you to do. Find the other people + + align:start position:0% +like you to do. Find the other people + + + align:start position:0% +like you to do. Find the other people +who have the same card as you. Um, uh, + + align:start position:0% +who have the same card as you. Um, uh, + + + align:start position:0% +who have the same card as you. Um, uh, +discuss what you learned from the + + align:start position:0% +discuss what you learned from the + + + align:start position:0% +discuss what you learned from the +readings, anything that sort of stands + + align:start position:0% +readings, anything that sort of stands + + + align:start position:0% +readings, anything that sort of stands +out to you, comes to your mind. But then + + align:start position:0% +out to you, comes to your mind. But then + + + align:start position:0% +out to you, comes to your mind. But then +I want you to make a chart, which you + + align:start position:0% +I want you to make a chart, which you + + + align:start position:0% +I want you to make a chart, which you +can do on the whiteboard or on our um, + + align:start position:0% +can do on the whiteboard or on our um, + + + align:start position:0% +can do on the whiteboard or on our um, +blue pieces of paper there. Um, that uh, + + align:start position:0% +blue pieces of paper there. Um, that uh, + + + align:start position:0% +blue pieces of paper there. Um, that uh, +that capture sort of three key ideas. + + align:start position:0% +that capture sort of three key ideas. + + + align:start position:0% +that capture sort of three key ideas. +First of all, who are all of the + + align:start position:0% +First of all, who are all of the + + + align:start position:0% +First of all, who are all of the +stakeholders who are involved in the + + align:start position:0% +stakeholders who are involved in the + + + align:start position:0% +stakeholders who are involved in the +implementation of this technology? One + + align:start position:0% +implementation of this technology? One + + + align:start position:0% +implementation of this technology? One +of the things that I think Larry Cubin + + align:start position:0% +of the things that I think Larry Cubin + + + align:start position:0% +of the things that I think Larry Cubin +is particularly wonderful at um is + + align:start position:0% +is particularly wonderful at um is + + + align:start position:0% +is particularly wonderful at um is +giving you a sense of all of the + + align:start position:0% +giving you a sense of all of the + + + align:start position:0% +giving you a sense of all of the +different hands that touch a technology + + align:start position:0% +different hands that touch a technology + + + align:start position:0% +different hands that touch a technology +making its way into a school and all the + + align:start position:0% +making its way into a school and all the + + + align:start position:0% +making its way into a school and all the +different hands that touch a technology + + align:start position:0% +different hands that touch a technology + + + align:start position:0% +different hands that touch a technology +when it's in the school. This is + + align:start position:0% +when it's in the school. This is + + + align:start position:0% +when it's in the school. This is +incredibly important for understanding + + align:start position:0% +incredibly important for understanding + + + align:start position:0% +incredibly important for understanding +how technologies actually get used um in + + align:start position:0% +how technologies actually get used um in + + + align:start position:0% +how technologies actually get used um in +in sort of a lot of times in like + + align:start position:0% +in sort of a lot of times in like + + + align:start position:0% +in sort of a lot of times in like +canonical design. And I think this comes + + align:start position:0% +canonical design. And I think this comes + + + align:start position:0% +canonical design. And I think this comes +up in sort of software engineering + + align:start position:0% +up in sort of software engineering + + + align:start position:0% +up in sort of software engineering +classes and things like this idea that + + align:start position:0% +classes and things like this idea that + + + align:start position:0% +classes and things like this idea that +like there's a programmer and a user and + + align:start position:0% +like there's a programmer and a user and + + + align:start position:0% +like there's a programmer and a user and +the user is like one person who's + + align:start position:0% +the user is like one person who's + + + align:start position:0% +the user is like one person who's +sitting at a keyboard with their fingers + + align:start position:0% +sitting at a keyboard with their fingers + + + align:start position:0% +sitting at a keyboard with their fingers +on the keyboard and like that's the + + align:start position:0% +on the keyboard and like that's the + + + align:start position:0% +on the keyboard and like that's the +person you need to pay attention to. And + + align:start position:0% +person you need to pay attention to. And + + + align:start position:0% +person you need to pay attention to. And +that like two-part model of like + + align:start position:0% +that like two-part model of like + + + align:start position:0% +that like two-part model of like +designer and user totally breaks down in + + align:start position:0% +designer and user totally breaks down in + + + align:start position:0% +designer and user totally breaks down in +schools. Um there are lots of people who + + align:start position:0% +schools. Um there are lots of people who + + + align:start position:0% +schools. Um there are lots of people who +are very different who could be + + align:start position:0% +are very different who could be + + + align:start position:0% +are very different who could be +considered users of technology in + + align:start position:0% +considered users of technology in + + + align:start position:0% +considered users of technology in +schools. Um, another thing that's that + + align:start position:0% +schools. Um, another thing that's that + + + align:start position:0% +schools. Um, another thing that's that +Larry Cubin does really well is he he he + + align:start position:0% +Larry Cubin does really well is he he he + + + align:start position:0% +Larry Cubin does really well is he he he +helps us pay attention to how these + + align:start position:0% +helps us pay attention to how these + + + align:start position:0% +helps us pay attention to how these +people have what I'll call different + + align:start position:0% +people have what I'll call different + + + align:start position:0% +people have what I'll call different +interests. By interests, I don't mean + + align:start position:0% +interests. By interests, I don't mean + + + align:start position:0% +interests. By interests, I don't mean +curiosities. I mean like incentives, + + align:start position:0% +curiosities. I mean like incentives, + + + align:start position:0% +curiosities. I mean like incentives, +stakes, sort of how a political + + align:start position:0% +stakes, sort of how a political + + + align:start position:0% +stakes, sort of how a political +scientist might use the word interest. + + align:start position:0% +scientist might use the word interest. + + + align:start position:0% +scientist might use the word interest. +Um, all of these different stakeholders + + align:start position:0% +Um, all of these different stakeholders + + + align:start position:0% +Um, all of these different stakeholders +are rewarded for different kinds of + + align:start position:0% +are rewarded for different kinds of + + + align:start position:0% +are rewarded for different kinds of +things. Um, they also have what we'll + + align:start position:0% +things. Um, they also have what we'll + + + align:start position:0% +things. Um, they also have what we'll +call disinterests or disincentives. they + + align:start position:0% +call disinterests or disincentives. they + + + align:start position:0% +call disinterests or disincentives. they +are also trying to avoid or will be + + align:start position:0% +are also trying to avoid or will be + + + align:start position:0% +are also trying to avoid or will be +punished for different kinds of things. + + align:start position:0% +punished for different kinds of things. + + + align:start position:0% +punished for different kinds of things. +Um so for the technology that you that + + align:start position:0% +Um so for the technology that you that + + + align:start position:0% +Um so for the technology that you that +you picked a card of and are talking + + align:start position:0% +you picked a card of and are talking + + + align:start position:0% +you picked a card of and are talking +with your colleagues about think of all + + align:start position:0% +with your colleagues about think of all + + + align:start position:0% +with your colleagues about think of all +of the different people who you think + + align:start position:0% +of the different people who you think + + + align:start position:0% +of the different people who you think +could be considered stakeholders in the + + align:start position:0% +could be considered stakeholders in the + + + align:start position:0% +could be considered stakeholders in the +implementation of this thing. What and + + align:start position:0% +implementation of this thing. What and + + + align:start position:0% +implementation of this thing. What and +then for each of those stakeholders come + + align:start position:0% +then for each of those stakeholders come + + + align:start position:0% +then for each of those stakeholders come +up with like a couple of their interests + + align:start position:0% +up with like a couple of their interests + + + align:start position:0% +up with like a couple of their interests +and a couple of their disinterests or + + align:start position:0% +and a couple of their disinterests or + + + align:start position:0% +and a couple of their disinterests or +disincentives or things that punish them + + align:start position:0% +disincentives or things that punish them + + + align:start position:0% +disincentives or things that punish them +or those kinds of things. Does that as a + + align:start position:0% +or those kinds of things. Does that as a + + + align:start position:0% +or those kinds of things. Does that as a +general exercise make sense? Um, and the + + align:start position:0% +general exercise make sense? Um, and the + + + align:start position:0% +general exercise make sense? Um, and the +thing that we're trying to do together + + align:start position:0% +thing that we're trying to do together + + + align:start position:0% +thing that we're trying to do together +is around we want to we want to try to + + align:start position:0% +is around we want to we want to try to + + + align:start position:0% +is around we want to we want to try to +recreate the world around these + + align:start position:0% +recreate the world around these + + + align:start position:0% +recreate the world around these +technologies. That's what I think Larry + + align:start position:0% +technologies. That's what I think Larry + + + align:start position:0% +technologies. That's what I think Larry +Cuban is so fabulous at, um, is saying + + align:start position:0% +Cuban is so fabulous at, um, is saying + + + align:start position:0% +Cuban is so fabulous at, um, is saying +like, yep, a television set is going to + + align:start position:0% +like, yep, a television set is going to + + + align:start position:0% +like, yep, a television set is going to +roll into a but it's going to roll into + + align:start position:0% +roll into a but it's going to roll into + + + align:start position:0% +roll into a but it's going to roll into +a classroom and into a school and into a + + align:start position:0% +a classroom and into a school and into a + + + align:start position:0% +a classroom and into a school and into a +community and there's all these people + + align:start position:0% +community and there's all these people + + + align:start position:0% +community and there's all these people +who are part of that. Um, that's what we + + align:start position:0% +who are part of that. Um, that's what we + + + align:start position:0% +who are part of that. Um, that's what we +really need to get out here. I'll tell + + align:start position:0% +really need to get out here. I'll tell + + + align:start position:0% +really need to get out here. I'll tell +the last thing I'll tell you before I + + align:start position:0% +the last thing I'll tell you before I + + + align:start position:0% +the last thing I'll tell you before I +cut you loose um, is Larry Cuban has a + + align:start position:0% +cut you loose um, is Larry Cuban has a + + + align:start position:0% +cut you loose um, is Larry Cuban has a +totally fascinating history himself. He + + align:start position:0% +totally fascinating history himself. He + + + align:start position:0% +totally fascinating history himself. He +was a social studies teacher in the 50s + + align:start position:0% +was a social studies teacher in the 50s + + + align:start position:0% +was a social studies teacher in the 50s +and 60s. Then he was a school principal. + + align:start position:0% +and 60s. Then he was a school principal. + + + align:start position:0% +and 60s. Then he was a school principal. +Then he was a superintendent. He was + + align:start position:0% +Then he was a superintendent. He was + + + align:start position:0% +Then he was a superintendent. He was +actually the superintendent in + + align:start position:0% +actually the superintendent in + + + align:start position:0% +actually the superintendent in +Arlington, Virginia. Um which is where + + align:start position:0% +Arlington, Virginia. Um which is where + + + align:start position:0% +Arlington, Virginia. Um which is where +my wife went to school. So when my wife + + align:start position:0% +my wife went to school. So when my wife + + + align:start position:0% +my wife went to school. So when my wife +was an elementary school student, um uh + + align:start position:0% +was an elementary school student, um uh + + + align:start position:0% +was an elementary school student, um uh +her her superintendent at the time was + + align:start position:0% +her her superintendent at the time was + + + align:start position:0% +her her superintendent at the time was +Larry Cuban. Um and are Arlington, + + align:start position:0% +Larry Cuban. Um and are Arlington, + + + align:start position:0% +Larry Cuban. Um and are Arlington, +Virginia. Fairfax. Close enough. Yeah. + + align:start position:0% +Virginia. Fairfax. Close enough. Yeah. + + + align:start position:0% +Virginia. Fairfax. Close enough. Yeah. +Yeah. Um and it was only after he had + + align:start position:0% +Yeah. Um and it was only after he had + + + align:start position:0% +Yeah. Um and it was only after he had +like a pretty distinguished career as a + + align:start position:0% +like a pretty distinguished career as a + + + align:start position:0% +like a pretty distinguished career as a +teacher, a principal, a superintendent + + align:start position:0% +teacher, a principal, a superintendent + + + align:start position:0% +teacher, a principal, a superintendent +that he went to Stanford. Um got his + + align:start position:0% +that he went to Stanford. Um got his + + + align:start position:0% +that he went to Stanford. Um got his +dissertation. um became a historian of + + align:start position:0% +dissertation. um became a historian of + + + align:start position:0% +dissertation. um became a historian of +education and then eventually a a + + align:start position:0% +education and then eventually a a + + + align:start position:0% +education and then eventually a a +history of education professor out + + align:start position:0% +history of education professor out + + + align:start position:0% +history of education professor out +there. Um so he's someone who's like + + align:start position:0% +there. Um so he's someone who's like + + + align:start position:0% +there. Um so he's someone who's like +extremely well read as I'm sure you got + + align:start position:0% +extremely well read as I'm sure you got + + + align:start position:0% +extremely well read as I'm sure you got +a sense of and things like that, but he + + align:start position:0% +a sense of and things like that, but he + + + align:start position:0% +a sense of and things like that, but he +also just deeply understands the kinds + + align:start position:0% +also just deeply understands the kinds + + + align:start position:0% +also just deeply understands the kinds +of things that make schools tick and + + align:start position:0% +of things that make schools tick and + + + align:start position:0% +of things that make schools tick and +make the people inside schools tick. + + align:start position:0% +make the people inside schools tick. + + + align:start position:0% +make the people inside schools tick. +Does this exercise make sense? Find the + + align:start position:0% +Does this exercise make sense? Find the + + + align:start position:0% +Does this exercise make sense? Find the +people with your cards. Move yourselves + + align:start position:0% +people with your cards. Move yourselves + + + align:start position:0% +people with your cards. Move yourselves +around. Make this little chart either on + + align:start position:0% +around. Make this little chart either on + + + align:start position:0% +around. Make this little chart either on +the board or on these blue pieces of + + align:start position:0% +the board or on these blue pieces of + + + align:start position:0% +the board or on these blue pieces of +paper. Ready? Go. + + align:start position:0% +paper. Ready? Go. + + + align:start position:0% +paper. Ready? Go. +That's a little bit th those things are + + align:start position:0% +That's a little bit th those things are + + + align:start position:0% +That's a little bit th those things are +those things are hugely important you + + align:start position:0% +those things are hugely important you + + + align:start position:0% +those things are hugely important you +know like like what like where does + + align:start position:0% +know like like what like where does + + + align:start position:0% +know like like what like where does +teaching actually happen like there's + + align:start position:0% +teaching actually happen like there's + + + align:start position:0% +teaching actually happen like there's +some human being you know who like needs + + align:start position:0% +some human being you know who like needs + + + align:start position:0% +some human being you know who like needs +to go to the bathroom and needs to eat + + align:start position:0% +to go to the bathroom and needs to eat + + + align:start position:0% +to go to the bathroom and needs to eat +and I mean he has that great quote in + + align:start position:0% +and I mean he has that great quote in + + + align:start position:0% +and I mean he has that great quote in +there it's not about film but television + + align:start position:0% +there it's not about film but television + + + align:start position:0% +there it's not about film but television +that they found that they're more likely + + align:start position:0% +that they found that they're more likely + + + align:start position:0% +that they found that they're more likely +to use television in the afternoon than + + align:start position:0% +to use television in the afternoon than + + + align:start position:0% +to use television in the afternoon than +in the mornings. Um and it and it all + + align:start position:0% +in the mornings. Um and it and it all + + + align:start position:0% +in the mornings. Um and it and it all +it's all like biology and culture like + + align:start position:0% +it's all like biology and culture like + + + align:start position:0% +it's all like biology and culture like +our brains work better in the morning. + + align:start position:0% +our brains work better in the morning. + + + align:start position:0% +our brains work better in the morning. +We're all a little flagging by the + + align:start position:0% +We're all a little flagging by the + + + align:start position:0% +We're all a little flagging by the +afternoon. Those kinds of things. Um, + + align:start position:0% +afternoon. Those kinds of things. Um, + + + align:start position:0% +afternoon. Those kinds of things. Um, +and so yeah, I think that like anybody + + align:start position:0% +and so yeah, I think that like anybody + + + align:start position:0% +and so yeah, I think that like anybody +who's building a technology has to think + + align:start position:0% +who's building a technology has to think + + + align:start position:0% +who's building a technology has to think +to themselves like, you know, what are + + align:start position:0% +to themselves like, you know, what are + + + align:start position:0% +to themselves like, you know, what are +you? Yeah. Yeah. What like what are the + + align:start position:0% +you? Yeah. Yeah. What like what are the + + + align:start position:0% +you? Yeah. Yeah. What like what are the +variations in a teacher's day? Like when + + align:start position:0% +variations in a teacher's day? Like when + + + align:start position:0% +variations in a teacher's day? Like when +do they have more energy or less energy? + + align:start position:0% +do they have more energy or less energy? + + + align:start position:0% +do they have more energy or less energy? +How does it fit into those kinds of + + align:start position:0% +How does it fit into those kinds of + + + align:start position:0% +How does it fit into those kinds of +cycles and things like that? Like those + + align:start position:0% +cycles and things like that? Like those + + + align:start position:0% +cycles and things like that? Like those +are every bit as real as you know the + + align:start position:0% +are every bit as real as you know the + + + align:start position:0% +are every bit as real as you know the +test score goals that we have or + + align:start position:0% +test score goals that we have or + + + align:start position:0% +test score goals that we have or +anything else. + + align:start position:0% + + + + align:start position:0% + +This is really good. This is really + + align:start position:0% +This is really good. This is really + + + align:start position:0% +This is really good. This is really +good. Take a few more minutes. Take a + + align:start position:0% +good. Take a few more minutes. Take a + + + align:start position:0% +good. Take a few more minutes. Take a +few more minutes. + + align:start position:0% + + + + align:start position:0% + +We're trying to think about interest for + + align:start position:0% +We're trying to think about interest for + + + align:start position:0% +We're trying to think about interest for +schools for producers. Sure. So, if + + align:start position:0% +schools for producers. Sure. So, if + + + align:start position:0% +schools for producers. Sure. So, if +you're a school, so if you're a school, + + align:start position:0% +you're a school, so if you're a school, + + + align:start position:0% +you're a school, so if you're a school, +what would make you go, h I'm not sure I + + align:start position:0% +what would make you go, h I'm not sure I + + + align:start position:0% +what would make you go, h I'm not sure I +want to do anything with films. It's so + + align:start position:0% +want to do anything with films. It's so + + + align:start position:0% +want to do anything with films. It's so +it's 1913. Um, silent films, you know, + + align:start position:0% +it's 1913. Um, silent films, you know, + + + align:start position:0% +it's 1913. Um, silent films, you know, +started coming out in earnest around the + + align:start position:0% +started coming out in earnest around the + + + align:start position:0% +started coming out in earnest around the +turn of the century. There's a handful + + align:start position:0% +turn of the century. There's a handful + + + align:start position:0% +turn of the century. There's a handful +of people um one, you know, the most + + align:start position:0% +of people um one, you know, the most + + + align:start position:0% +of people um one, you know, the most +prominent of them is Thomas Edison. You + + align:start position:0% +prominent of them is Thomas Edison. You + + + align:start position:0% +prominent of them is Thomas Edison. You +know, a guy invents a light bulb. Um and + + align:start position:0% +know, a guy invents a light bulb. Um and + + + align:start position:0% +know, a guy invents a light bulb. Um and +he gets in front of Congress and he + + align:start position:0% +he gets in front of Congress and he + + + align:start position:0% +he gets in front of Congress and he +says, you know, he's first in 1913, he + + align:start position:0% +says, you know, he's first in 1913, he + + + align:start position:0% +says, you know, he's first in 1913, he +says, I mean, I'll read the other quote, + + align:start position:0% +says, I mean, I'll read the other quote, + + + align:start position:0% +says, I mean, I'll read the other quote, +but he says, um, in a decade, textbooks + + align:start position:0% +but he says, um, in a decade, textbooks + + + align:start position:0% +but he says, um, in a decade, textbooks +will be replaced by film strips. That's + + align:start position:0% +will be replaced by film strips. That's + + + align:start position:0% +will be replaced by film strips. That's +how powerful this new technology is + + align:start position:0% +how powerful this new technology is + + + align:start position:0% +how powerful this new technology is +going to be. Um, if you're a school + + align:start position:0% +going to be. Um, if you're a school + + + align:start position:0% +going to be. Um, if you're a school +principal, what would be some things + + align:start position:0% +principal, what would be some things + + + align:start position:0% +principal, what would be some things +that make you go, you're pretty smart, + + align:start position:0% +that make you go, you're pretty smart, + + + align:start position:0% +that make you go, you're pretty smart, +Thomas, but I'm not so sure about this + + align:start position:0% +Thomas, but I'm not so sure about this + + + align:start position:0% +Thomas, but I'm not so sure about this +one? + + align:start position:0% +one? + + + align:start position:0% +one? +Maybe if they just put a bunch of money + + align:start position:0% +Maybe if they just put a bunch of money + + + align:start position:0% +Maybe if they just put a bunch of money +into textbooks. Sure. So yeah, they have + + align:start position:0% +into textbooks. Sure. So yeah, they have + + + align:start position:0% +into textbooks. Sure. So yeah, they have +an entire infrastructure built around + + align:start position:0% +an entire infrastructure built around + + + align:start position:0% +an entire infrastructure built around +the existing technologies. They h they + + align:start position:0% +the existing technologies. They h they + + + align:start position:0% +the existing technologies. They h they +have shelves on the wall. They have + + align:start position:0% +have shelves on the wall. They have + + + align:start position:0% +have shelves on the wall. They have +libraries full of books. Every one of + + align:start position:0% +libraries full of books. Every one of + + + align:start position:0% +libraries full of books. Every one of +their teachers has been trained to teach + + align:start position:0% +their teachers has been trained to teach + + + align:start position:0% +their teachers has been trained to teach +with textbooks. And not a single one of + + align:start position:0% +with textbooks. And not a single one of + + + align:start position:0% +with textbooks. And not a single one of +their teachers in you know when these + + align:start position:0% +their teachers in you know when these + + + align:start position:0% +their teachers in you know when these +things are first introduced has ever + + align:start position:0% +things are first introduced has ever + + + align:start position:0% +things are first introduced has ever +been in a class as a student learning + + align:start position:0% +been in a class as a student learning + + + align:start position:0% +been in a class as a student learning +from a film. So you have this huge + + align:start position:0% +from a film. So you have this huge + + + align:start position:0% +from a film. So you have this huge +inherent conservatism in the system. So + + align:start position:0% +inherent conservatism in the system. So + + + align:start position:0% +inherent conservatism in the system. So +that could be one. What would be what + + align:start position:0% +that could be one. What would be what + + + align:start position:0% +that could be one. What would be what +would be some others? + + align:start position:0% + + + + align:start position:0% + +I mean, yeah. I mean, I I guess it's + + align:start position:0% +I mean, yeah. I mean, I I guess it's + + + align:start position:0% +I mean, yeah. I mean, I I guess it's +kind of adding on to that, but like + + align:start position:0% +kind of adding on to that, but like + + + align:start position:0% +kind of adding on to that, but like +integrating it into like a classroom + + align:start position:0% +integrating it into like a classroom + + + align:start position:0% +integrating it into like a classroom +setting, like how how would they even + + align:start position:0% +setting, like how how would they even + + + align:start position:0% +setting, like how how would they even +like + + align:start position:0% +like + + + align:start position:0% +like +uh integrate into like even even if + + align:start position:0% +uh integrate into like even even if + + + align:start position:0% +uh integrate into like even even if +they're like completely on board like + + align:start position:0% +they're like completely on board like + + + align:start position:0% +they're like completely on board like +like what how would they even integrate + + align:start position:0% +like what how would they even integrate + + + align:start position:0% +like what how would they even integrate +it into a classroom? What for films? + + align:start position:0% +it into a classroom? What for films? + + + align:start position:0% +it into a classroom? What for films? +What would be what would be some of the + + align:start position:0% +What would be what would be some of the + + + align:start position:0% +What would be what would be some of the +challenges of integration? + + align:start position:0% +challenges of integration? + + + align:start position:0% +challenges of integration? +Um like + + align:start position:0% +Um like + + + align:start position:0% +Um like +the technology that you would need to + + align:start position:0% +the technology that you would need to + + + align:start position:0% +the technology that you would need to +like uh put into a classroom or like to + + align:start position:0% +like uh put into a classroom or like to + + + align:start position:0% +like uh put into a classroom or like to +a school. Say tell me specifically for + + align:start position:0% +a school. Say tell me specifically for + + + align:start position:0% +a school. Say tell me specifically for +films what some of that technology might + + align:start position:0% +films what some of that technology might + + + align:start position:0% +films what some of that technology might +be. Um I mean like isn't I I don't think + + align:start position:0% +be. Um I mean like isn't I I don't think + + + align:start position:0% +be. Um I mean like isn't I I don't think +like the the projectors in like back + + align:start position:0% +like the the projectors in like back + + + align:start position:0% +like the the projectors in like back +then could like fit into like a + + align:start position:0% +then could like fit into like a + + + align:start position:0% +then could like fit into like a +classroom. Oh, they so they could I mean + + align:start position:0% +classroom. Oh, they so they could I mean + + + align:start position:0% +classroom. Oh, they so they could I mean +you know like they're they're portable + + align:start position:0% +you know like they're they're portable + + + align:start position:0% +you know like they're they're portable +enough but they're big. They're these + + align:start position:0% +enough but they're big. They're these + + + align:start position:0% +enough but they're big. They're these +like big lumbering machines for which + + align:start position:0% +like big lumbering machines for which + + + align:start position:0% +like big lumbering machines for which +the rooms are like if you have if you + + align:start position:0% +the rooms are like if you have if you + + + align:start position:0% +the rooms are like if you have if you +have a classroom like let's say you have + + align:start position:0% +have a classroom like let's say you have + + + align:start position:0% +have a classroom like let's say you have +a big population growth and so you're + + align:start position:0% +a big population growth and so you're + + + align:start position:0% +a big population growth and so you're +you're you built you you know someone in + + align:start position:0% +you're you built you you know someone in + + + align:start position:0% +you're you built you you know someone in +the 1850s built a school and it was 12 + + align:start position:0% +the 1850s built a school and it was 12 + + + align:start position:0% +the 1850s built a school and it was 12 +kids per classroom and now you're + + align:start position:0% +kids per classroom and now you're + + + align:start position:0% +kids per classroom and now you're +putting 18 kids per classroom in there. + + align:start position:0% +putting 18 kids per classroom in there. + + + align:start position:0% +putting 18 kids per classroom in there. +Like a totally legitimate reason would + + align:start position:0% +Like a totally legitimate reason would + + + align:start position:0% +Like a totally legitimate reason would +be there is not space in this room to + + align:start position:0% +be there is not space in this room to + + + align:start position:0% +be there is not space in this room to +physically move this machine. Like what + + align:start position:0% +physically move this machine. Like what + + + align:start position:0% +physically move this machine. Like what +are some other sort of what else do you + + align:start position:0% +are some other sort of what else do you + + + align:start position:0% +are some other sort of what else do you +need for films as a technology to be + + align:start position:0% +need for films as a technology to be + + + align:start position:0% +need for films as a technology to be +able to be implemented? Do you need a + + align:start position:0% +able to be implemented? Do you need a + + + align:start position:0% +able to be implemented? Do you need a +giant projector? You're going to put + + align:start position:0% +giant projector? You're going to put + + + align:start position:0% +giant projector? You're going to put +thing on wheels. What else do you need? + + align:start position:0% +thing on wheels. What else do you need? + + + align:start position:0% +thing on wheels. What else do you need? +A place to actually project it onto. + + align:start position:0% +A place to actually project it onto. + + + align:start position:0% +A place to actually project it onto. +Okay, good. You're going to have to go + + align:start position:0% +Okay, good. You're going to have to go + + + align:start position:0% +Okay, good. You're going to have to go +to all your classrooms and you're going + + align:start position:0% +to all your classrooms and you're going + + + align:start position:0% +to all your classrooms and you're going +to have to install screens at the front + + align:start position:0% +to have to install screens at the front + + + align:start position:0% +to have to install screens at the front +of the room. Like not the hugest + + align:start position:0% +of the room. Like not the hugest + + + align:start position:0% +of the room. Like not the hugest +challenge, but also not free, you know, + + align:start position:0% +challenge, but also not free, you know, + + + align:start position:0% +challenge, but also not free, you know, +not like like so who's going to do these + + align:start position:0% +not like like so who's going to do these + + + align:start position:0% +not like like so who's going to do these +things? Um, you know, the uh the films + + align:start position:0% +things? Um, you know, the uh the films + + + align:start position:0% +things? Um, you know, the uh the films +also came on these like huge reels. Um, + + align:start position:0% +also came on these like huge reels. Um, + + + align:start position:0% +also came on these like huge reels. Um, +you know, it wasn't just like, you know, + + align:start position:0% +you know, it wasn't just like, you know, + + + align:start position:0% +you know, it wasn't just like, you know, +pick your YouTube channel and play like + + align:start position:0% +pick your YouTube channel and play like + + + align:start position:0% +pick your YouTube channel and play like +where in your building are you going to + + align:start position:0% +where in your building are you going to + + + align:start position:0% +where in your building are you going to +keep a library of film reels? Who's + + align:start position:0% +keep a library of film reels? Who's + + + align:start position:0% +keep a library of film reels? Who's +going to organize those libraries of + + align:start position:0% +going to organize those libraries of + + + align:start position:0% +going to organize those libraries of +film reels? Like um you know if you have + + align:start position:0% +film reels? Like um you know if you have + + + align:start position:0% +film reels? Like um you know if you have +four elementary schools in an or four + + align:start position:0% +four elementary schools in an or four + + + align:start position:0% +four elementary schools in an or four +elementary classroom like let's say have + + align:start position:0% +elementary classroom like let's say have + + + align:start position:0% +elementary classroom like let's say have +four first grades, are you going to buy + + align:start position:0% +four first grades, are you going to buy + + + align:start position:0% +four first grades, are you going to buy +four copies of this film so that + + align:start position:0% +four copies of this film so that + + + align:start position:0% +four copies of this film so that +everyone can watch it at the same time? + + align:start position:0% +everyone can watch it at the same time? + + + align:start position:0% +everyone can watch it at the same time? +If not, how are you going to like + + align:start position:0% +If not, how are you going to like + + + align:start position:0% +If not, how are you going to like +physically organize and move like this + + align:start position:0% +physically organize and move like this + + + align:start position:0% +physically organize and move like this +giant reel from one space to another? + + align:start position:0% +giant reel from one space to another? + + + align:start position:0% +giant reel from one space to another? +Those are all those are all you know you + + align:start position:0% +Those are all those are all you know you + + + align:start position:0% +Those are all those are all you know you +could imagine the principal being like + + align:start position:0% +could imagine the principal being like + + + align:start position:0% +could imagine the principal being like +but how are we but how are we but how + + align:start position:0% +but how are we but how are we but how + + + align:start position:0% +but how are we but how are we but how +are we but how are we and all this stuff + + align:start position:0% +are we but how are we and all this stuff + + + align:start position:0% +are we but how are we and all this stuff +costs money. Um, so those are all kinds + + align:start position:0% +costs money. Um, so those are all kinds + + + align:start position:0% +costs money. Um, so those are all kinds +of, you know, like like, you know, + + align:start position:0% +of, you know, like like, you know, + + + align:start position:0% +of, you know, like like, you know, +Thomas Edison is here telling you that + + align:start position:0% +Thomas Edison is here telling you that + + + align:start position:0% +Thomas Edison is here telling you that +you're going to get 100% efficient + + align:start position:0% +you're going to get 100% efficient + + + align:start position:0% +you're going to get 100% efficient +learning through this thing, which is + + align:start position:0% +learning through this thing, which is + + + align:start position:0% +learning through this thing, which is +the potential gains, which you no one + + align:start position:0% +the potential gains, which you no one + + + align:start position:0% +the potential gains, which you no one +has any evidence for because it hasn't + + align:start position:0% +has any evidence for because it hasn't + + + align:start position:0% +has any evidence for because it hasn't +happened yet. But you've got to think to + + align:start position:0% +happened yet. But you've got to think to + + + align:start position:0% +happened yet. But you've got to think to +yourself like like what are all these + + align:start position:0% +yourself like like what are all these + + + align:start position:0% +yourself like like what are all these +costs? What are all these material + + align:start position:0% +costs? What are all these material + + + align:start position:0% +costs? What are all these material +changes? Yeah. So think about how you + + align:start position:0% +changes? Yeah. So think about how you + + + align:start position:0% +changes? Yeah. So think about how you +can articulate some of those things. But + + align:start position:0% +can articulate some of those things. But + + + align:start position:0% +can articulate some of those things. But +good like when you really get like, you + + align:start position:0% +good like when you really get like, you + + + align:start position:0% +good like when you really get like, you +know, for to to do this exercise, well, + + align:start position:0% +know, for to to do this exercise, well, + + + align:start position:0% +know, for to to do this exercise, well, +you have to like what exactly is this + + align:start position:0% +you have to like what exactly is this + + + align:start position:0% +you have to like what exactly is this +technology? Like like even physically, + + align:start position:0% +technology? Like like even physically, + + + align:start position:0% +technology? Like like even physically, +what does it require? How many of these + + align:start position:0% +what does it require? How many of these + + + align:start position:0% +what does it require? How many of these +things do you need to buy? How much do + + align:start position:0% +things do you need to buy? How much do + + + align:start position:0% +things do you need to buy? How much do +they cost? All that kind of stuff. How + + align:start position:0% +they cost? All that kind of stuff. How + + + align:start position:0% +they cost? All that kind of stuff. How +reusable are they? Um, + + align:start position:0% + + + + align:start position:0% + +okay. This is really good. Why don't we + + align:start position:0% +okay. This is really good. Why don't we + + + align:start position:0% +okay. This is really good. Why don't we +take a break here? Um, go ahead and you + + align:start position:0% +take a break here? Um, go ahead and you + + + align:start position:0% +take a break here? Um, go ahead and you +can sit back down to the seats that you + + align:start position:0% +can sit back down to the seats that you + + + align:start position:0% +can sit back down to the seats that you +were at. Um, I think everyone's written + + align:start position:0% +were at. Um, I think everyone's written + + + align:start position:0% +were at. Um, I think everyone's written +kind of broadly enough um that we'll be + + align:start position:0% +kind of broadly enough um that we'll be + + + align:start position:0% +kind of broadly enough um that we'll be +able to see from a + + align:start position:0% +able to see from a + + + align:start position:0% +able to see from a +distance. But yeah, really good. Really + + align:start position:0% +distance. But yeah, really good. Really + + + align:start position:0% +distance. But yeah, really good. Really +good. Now I need to find a little spot + + align:start position:0% +good. Now I need to find a little spot + + + align:start position:0% +good. Now I need to find a little spot +for me to um + + align:start position:0% +for me to um + + + align:start position:0% +for me to um +everyone's last minute notes. Every + + align:start position:0% +everyone's last minute notes. Every + + + align:start position:0% +everyone's last minute notes. Every +Yeah. Yeah. Now is your chance to put + + align:start position:0% +Yeah. Yeah. Now is your chance to put + + + align:start position:0% +Yeah. Yeah. Now is your chance to put +the final the final few things up there. + + align:start position:0% +the final the final few things up there. + + + align:start position:0% +the final the final few things up there. +Um good. So every What was the minimum + + align:start position:0% +Um good. So every What was the minimum + + + align:start position:0% +Um good. So every What was the minimum +number of stakeholders people came up + + align:start position:0% +number of stakeholders people came up + + + align:start position:0% +number of stakeholders people came up +with? Um these guys are the winners with + + align:start position:0% +with? Um these guys are the winners with + + + align:start position:0% +with? Um these guys are the winners with +the longest list. Let's just read it out + + align:start position:0% +the longest list. Let's just read it out + + + align:start position:0% +the longest list. Let's just read it out +loud. Co. Oh no. The state admin, + + align:start position:0% +loud. Co. Oh no. The state admin, + + + align:start position:0% +loud. Co. Oh no. The state admin, +parents, teachers, students, + + align:start position:0% +parents, teachers, students, + + + align:start position:0% +parents, teachers, students, +corporations, manufacturers, edtech + + align:start position:0% +corporations, manufacturers, edtech + + + align:start position:0% +corporations, manufacturers, edtech +investors, developers, policy makers. + + align:start position:0% +investors, developers, policy makers. + + + align:start position:0% +investors, developers, policy makers. +Great. So, just as a starting point, I + + align:start position:0% +Great. So, just as a starting point, I + + + align:start position:0% +Great. So, just as a starting point, I +mean, there are some other ones that + + align:start position:0% +mean, there are some other ones that + + + align:start position:0% +mean, there are some other ones that +showed up around here, studios, + + align:start position:0% +showed up around here, studios, + + + align:start position:0% +showed up around here, studios, +broadcasters, the FCC, um, that sort of + + align:start position:0% +broadcasters, the FCC, um, that sort of + + + align:start position:0% +broadcasters, the FCC, um, that sort of +different psychologists. Yeah, there are + + align:start position:0% +different psychologists. Yeah, there are + + + align:start position:0% +different psychologists. Yeah, there are +a lot of people who have something at + + align:start position:0% +a lot of people who have something at + + + align:start position:0% +a lot of people who have something at +stake in these decisions. They're + + align:start position:0% +stake in these decisions. They're + + + align:start position:0% +stake in these decisions. They're +complex, multihuman kinds of decisions. + + align:start position:0% +complex, multihuman kinds of decisions. + + + align:start position:0% +complex, multihuman kinds of decisions. +So, that's a good start. Um, let me just + + align:start position:0% +So, that's a good start. Um, let me just + + + align:start position:0% +So, that's a good start. Um, let me just +read. Um, so given how complex these + + align:start position:0% +read. Um, so given how complex these + + + align:start position:0% +read. Um, so given how complex these +things are, why are folks so + + align:start position:0% +things are, why are folks so + + + align:start position:0% +things are, why are folks so +enthusiastic about it? Let's ask Thomas + + align:start position:0% +enthusiastic about it? Let's ask Thomas + + + align:start position:0% +enthusiastic about it? Let's ask Thomas +Edison. Um, what does Thomas Edison + + align:start position:0% +Edison. Um, what does Thomas Edison + + + align:start position:0% +Edison. Um, what does Thomas Edison +think about this? I believe that the + + align:start position:0% +think about this? I believe that the + + + align:start position:0% +think about this? I believe that the +motion picture is destined to + + align:start position:0% +motion picture is destined to + + + align:start position:0% +motion picture is destined to +revolutionize our educational system and + + align:start position:0% +revolutionize our educational system and + + + align:start position:0% +revolutionize our educational system and +that in a few years it will supplant + + align:start position:0% +that in a few years it will supplant + + + align:start position:0% +that in a few years it will supplant +largely if not entirely the use of + + align:start position:0% +largely if not entirely the use of + + + align:start position:0% +largely if not entirely the use of +textbooks. I should say that on the + + align:start position:0% +textbooks. I should say that on the + + + align:start position:0% +textbooks. I should say that on the +average we get about 2% efficiency out + + align:start position:0% +average we get about 2% efficiency out + + + align:start position:0% +average we get about 2% efficiency out +of school books as they are written + + align:start position:0% +of school books as they are written + + + align:start position:0% +of school books as they are written +today. You're laughing. Why are you + + align:start position:0% +today. You're laughing. Why are you + + + align:start position:0% +today. You're laughing. Why are you +laughing? Thomas Edison is just here + + align:start position:0% +laughing? Thomas Edison is just here + + + align:start position:0% +laughing? Thomas Edison is just here +making up. He doesn't 2% that + + align:start position:0% +making up. He doesn't 2% that + + + align:start position:0% +making up. He doesn't 2% that +doesn't mean a thing. He was good at + + align:start position:0% +doesn't mean a thing. He was good at + + + align:start position:0% +doesn't mean a thing. He was good at +light bulbs. He wasn't maybe as good at + + align:start position:0% +light bulbs. He wasn't maybe as good at + + + align:start position:0% +light bulbs. He wasn't maybe as good at +this. Um, the education of the future as + + align:start position:0% +this. Um, the education of the future as + + + align:start position:0% +this. Um, the education of the future as +I see it will be conducted through the + + align:start position:0% +I see it will be conducted through the + + + align:start position:0% +I see it will be conducted through the +medium of the motion picture where it + + align:start position:0% +medium of the motion picture where it + + + align:start position:0% +medium of the motion picture where it +should be possible to obtain 100% + + align:start position:0% +should be possible to obtain 100% + + + align:start position:0% +should be possible to obtain 100% +efficiency. Thomas Edison 1922. Um, + + align:start position:0% +efficiency. Thomas Edison 1922. Um, + + + align:start position:0% +efficiency. Thomas Edison 1922. Um, +you'll read a couple of other quotes + + align:start position:0% +you'll read a couple of other quotes + + + align:start position:0% +you'll read a couple of other quotes +that I have from Thomas Edison. One of + + align:start position:0% +that I have from Thomas Edison. One of + + + align:start position:0% +that I have from Thomas Edison. One of +them is in here in in failure to disrupt + + align:start position:0% +them is in here in in failure to disrupt + + + align:start position:0% +them is in here in in failure to disrupt +when you read that. But in 1913, he went + + align:start position:0% +when you read that. But in 1913, he went + + + align:start position:0% +when you read that. But in 1913, he went +in front of Congress and said in 10 + + align:start position:0% +in front of Congress and said in 10 + + + align:start position:0% +in front of Congress and said in 10 +years the textbook will entire will be + + align:start position:0% +years the textbook will entire will be + + + align:start position:0% +years the textbook will entire will be +entirely replaced by um film strips. And + + align:start position:0% +entirely replaced by um film strips. And + + + align:start position:0% +entirely replaced by um film strips. And +then he went back 10 years later in 1923 + + align:start position:0% +then he went back 10 years later in 1923 + + + align:start position:0% +then he went back 10 years later in 1923 +and he said in 20 years textbooks will + + align:start position:0% +and he said in 20 years textbooks will + + + align:start position:0% +and he said in 20 years textbooks will +be entirely replaced by film strips. Um + + align:start position:0% +be entirely replaced by film strips. Um + + + align:start position:0% +be entirely replaced by film strips. Um +I think you can find many similar kinds + + align:start position:0% +I think you can find many similar kinds + + + align:start position:0% +I think you can find many similar kinds +of arguments that are made today. Um I + + align:start position:0% +of arguments that are made today. Um I + + + align:start position:0% +of arguments that are made today. Um I +think you will not have a hard time um + + align:start position:0% +think you will not have a hard time um + + + align:start position:0% +think you will not have a hard time um +finding people who tell you that the + + align:start position:0% +finding people who tell you that the + + + align:start position:0% +finding people who tell you that the +oldfashioned techniques are only 2% + + align:start position:0% +oldfashioned techniques are only 2% + + + align:start position:0% +oldfashioned techniques are only 2% +efficient but the new ones will be 100% + + align:start position:0% +efficient but the new ones will be 100% + + + align:start position:0% +efficient but the new ones will be 100% +efficient. Um so that's the promise. the + + align:start position:0% +efficient. Um so that's the promise. the + + + align:start position:0% +efficient. Um so that's the promise. the +promise is that we could do + + align:start position:0% +promise is that we could do + + + align:start position:0% +promise is that we could do +substantially better than we're doing + + align:start position:0% +substantially better than we're doing + + + align:start position:0% +substantially better than we're doing +right now if we if we think about + + align:start position:0% +right now if we if we think about + + + align:start position:0% +right now if we if we think about +implementing all of these uh different + + align:start position:0% +implementing all of these uh different + + + align:start position:0% +implementing all of these uh different +kinds of technologies. Um so an + + align:start position:0% +kinds of technologies. Um so an + + + align:start position:0% +kinds of technologies. Um so an +intuition that you can develop um is + + align:start position:0% +intuition that you can develop um is + + + align:start position:0% +intuition that you can develop um is +that this is this is a century old + + align:start position:0% +that this is this is a century old + + + align:start position:0% +that this is this is a century old +enterprise. Um for the last 100 110 + + align:start position:0% +enterprise. Um for the last 100 110 + + + align:start position:0% +enterprise. Um for the last 100 110 +years people have thought how can we + + align:start position:0% +years people have thought how can we + + + align:start position:0% +years people have thought how can we +take analog technologies and eventually + + align:start position:0% +take analog technologies and eventually + + + align:start position:0% +take analog technologies and eventually +digital technologies bring them into + + align:start position:0% +digital technologies bring them into + + + align:start position:0% +digital technologies bring them into +schools to improve learning. Um there + + align:start position:0% +schools to improve learning. Um there + + + align:start position:0% +schools to improve learning. Um there +are millions of people who work on + + align:start position:0% +are millions of people who work on + + + align:start position:0% +are millions of people who work on +education. Many of them are very very + + align:start position:0% +education. Many of them are very very + + + align:start position:0% +education. Many of them are very very +smart. Um from the earliest, you know, + + align:start position:0% +smart. Um from the earliest, you know, + + + align:start position:0% +smart. Um from the earliest, you know, +you read a little bit about um uh + + align:start position:0% +you read a little bit about um uh + + + align:start position:0% +you read a little bit about um uh +personal computers kind of from the 70s + + align:start position:0% +personal computers kind of from the 70s + + + align:start position:0% +personal computers kind of from the 70s +and 80s, the Apple 2 plus kind of the + + align:start position:0% +and 80s, the Apple 2 plus kind of the + + + align:start position:0% +and 80s, the Apple 2 plus kind of the +generation of computers that I grew up + + align:start position:0% +generation of computers that I grew up + + + align:start position:0% +generation of computers that I grew up +with, but that's actually like 20 years + + align:start position:0% +with, but that's actually like 20 years + + + align:start position:0% +with, but that's actually like 20 years +into the game. Um from the moment people + + align:start position:0% +into the game. Um from the moment people + + + align:start position:0% +into the game. Um from the moment people +built computers the size of this room, + + align:start position:0% +built computers the size of this room, + + + align:start position:0% +built computers the size of this room, +um computer scientists, educators, + + align:start position:0% +um computer scientists, educators, + + + align:start position:0% +um computer scientists, educators, +learning scientists partnered together + + align:start position:0% +learning scientists partnered together + + + align:start position:0% +learning scientists partnered together +to try to figure out if there's some way + + align:start position:0% +to try to figure out if there's some way + + + align:start position:0% +to try to figure out if there's some way +to use computers to teach people. So, so + + align:start position:0% +to use computers to teach people. So, so + + + align:start position:0% +to use computers to teach people. So, so +just compute, you know, not even all + + align:start position:0% +just compute, you know, not even all + + + align:start position:0% +just compute, you know, not even all +these other radio, film, other things. + + align:start position:0% +these other radio, film, other things. + + + align:start position:0% +these other radio, film, other things. +Computing alone is like a 70-year + + align:start position:0% +Computing alone is like a 70-year + + + align:start position:0% +Computing alone is like a 70-year +enterprise of trying to improve schools. + + align:start position:0% +enterprise of trying to improve schools. + + + align:start position:0% +enterprise of trying to improve schools. +There are lots of things that we've + + align:start position:0% +There are lots of things that we've + + + align:start position:0% +There are lots of things that we've +tried and learned in 70 years. So, one + + align:start position:0% +tried and learned in 70 years. So, one + + + align:start position:0% +tried and learned in 70 years. So, one +intuition that I hope you will take away + + align:start position:0% +intuition that I hope you will take away + + + align:start position:0% +intuition that I hope you will take away +from this class is that when you're + + align:start position:0% +from this class is that when you're + + + align:start position:0% +from this class is that when you're +thinking about an education technology + + align:start position:0% +thinking about an education technology + + + align:start position:0% +thinking about an education technology +problem of any form or type, about a + + align:start position:0% +problem of any form or type, about a + + + align:start position:0% +problem of any form or type, about a +design problem, an implementation + + align:start position:0% +design problem, an implementation + + + align:start position:0% +design problem, an implementation +problem, a policy problem, you should + + align:start position:0% +problem, a policy problem, you should + + + align:start position:0% +problem, a policy problem, you should +think to yourself, we probably have done + + align:start position:0% +think to yourself, we probably have done + + + align:start position:0% +think to yourself, we probably have done +something like this before. Um there is + + align:start position:0% +something like this before. Um there is + + + align:start position:0% +something like this before. Um there is +nothing that is so new, so utterly + + align:start position:0% +nothing that is so new, so utterly + + + align:start position:0% +nothing that is so new, so utterly +different that there aren't like cognate + + align:start position:0% +different that there aren't like cognate + + + align:start position:0% +different that there aren't like cognate +examples that could help us think + + align:start position:0% +examples that could help us think + + + align:start position:0% +examples that could help us think +through whatever these challenges are. + + align:start position:0% +through whatever these challenges are. + + + align:start position:0% +through whatever these challenges are. +Um let's think about a couple of these + + align:start position:0% +Um let's think about a couple of these + + + align:start position:0% +Um let's think about a couple of these +stakeholders. Which stakeholders seem to + + align:start position:0% +stakeholders. Which stakeholders seem to + + + align:start position:0% +stakeholders. Which stakeholders seem to +appear pretty much in all of them? + + align:start position:0% +appear pretty much in all of them? + + + align:start position:0% +appear pretty much in all of them? +What's who's who seem to be sort of + + align:start position:0% +What's who's who seem to be sort of + + + align:start position:0% +What's who's who seem to be sort of +universal stakeholders? + + align:start position:0% +universal stakeholders? + + + align:start position:0% +universal stakeholders? +Teachers. Teachers. Let's start with + + align:start position:0% +Teachers. Teachers. Let's start with + + + align:start position:0% +Teachers. Teachers. Let's start with +them because they're the best. Um I I + + align:start position:0% +them because they're the best. Um I I + + + align:start position:0% +them because they're the best. Um I I +love teachers. I would I mean definitely + + align:start position:0% +love teachers. I would I mean definitely + + + align:start position:0% +love teachers. I would I mean definitely +one of the reasons why I do what I do is + + align:start position:0% +one of the reasons why I do what I do is + + + align:start position:0% +one of the reasons why I do what I do is +I just think teachers are great. + + align:start position:0% +I just think teachers are great. + + + align:start position:0% +I just think teachers are great. +Um what what kinds of things get + + align:start position:0% +Um what what kinds of things get + + + align:start position:0% +Um what what kinds of things get +teachers excited? What what what if if + + align:start position:0% +teachers excited? What what what if if + + + align:start position:0% +teachers excited? What what what if if +you're if you're if you want to get a + + align:start position:0% +you're if you're if you want to get a + + + align:start position:0% +you're if you're if you want to get a +teacher using education technology, what + + align:start position:0% +teacher using education technology, what + + + align:start position:0% +teacher using education technology, what +are the what are the felt needs that + + align:start position:0% +are the what are the felt needs that + + + align:start position:0% +are the what are the felt needs that +they have that are going to be really + + align:start position:0% +they have that are going to be really + + + align:start position:0% +they have that are going to be really +important to them? This is one that I + + align:start position:0% +important to them? This is one that I + + + align:start position:0% +important to them? This is one that I +think will be pretty consistent across a + + align:start position:0% +think will be pretty consistent across a + + + align:start position:0% +think will be pretty consistent across a +bunch of these, but we can see if there + + align:start position:0% +bunch of these, but we can see if there + + + align:start position:0% +bunch of these, but we can see if there +are differences, too. Reducing their + + align:start position:0% +are differences, too. Reducing their + + + align:start position:0% +are differences, too. Reducing their +workload. Okay, good. I love it. + + align:start position:0% +workload. Okay, good. I love it. + + + align:start position:0% +workload. Okay, good. I love it. +reducing + + align:start position:0% +reducing + + + align:start position:0% +reducing +workload. Why is that so important to + + align:start position:0% +workload. Why is that so important to + + + align:start position:0% +workload. Why is that so important to +teachers? + + align:start position:0% +teachers? + + + align:start position:0% +teachers? +It's because they have so much they have + + align:start position:0% +It's because they have so much they have + + + align:start position:0% +It's because they have so much they have +so much to do. These are not people who + + align:start position:0% +so much to do. These are not people who + + + align:start position:0% +so much to do. These are not people who +spend a bunch of time like sitting + + align:start position:0% +spend a bunch of time like sitting + + + align:start position:0% +spend a bunch of time like sitting +around waiting for the phone to ring or + + align:start position:0% +around waiting for the phone to ring or + + + align:start position:0% +around waiting for the phone to ring or +something like that. Um teacher workload + + align:start position:0% +something like that. Um teacher workload + + + align:start position:0% +something like that. Um teacher workload +in the United States is actually in + + align:start position:0% +in the United States is actually in + + + align:start position:0% +in the United States is actually in +certain ways like much higher than other + + align:start position:0% +certain ways like much higher than other + + + align:start position:0% +certain ways like much higher than other +comparable OECD countries. So O is the + + align:start position:0% +comparable OECD countries. So O is the + + + align:start position:0% +comparable OECD countries. So O is the +organization of economic cooperative + + align:start position:0% +organization of economic cooperative + + + align:start position:0% +organization of economic cooperative +development something like that. It's + + align:start position:0% +development something like that. It's + + + align:start position:0% +development something like that. It's +like rich countries 30 or 40 rich + + align:start position:0% +like rich countries 30 or 40 rich + + + align:start position:0% +like rich countries 30 or 40 rich +countries. Um, American teachers + + align:start position:0% +countries. Um, American teachers + + + align:start position:0% +countries. Um, American teachers +compared to our colleagues in other + + align:start position:0% +compared to our colleagues in other + + + align:start position:0% +compared to our colleagues in other +countries spend more time in front of + + align:start position:0% +countries spend more time in front of + + + align:start position:0% +countries spend more time in front of +students actually directly teaching than + + align:start position:0% +students actually directly teaching than + + + align:start position:0% +students actually directly teaching than +in many other places. Um, so many other + + align:start position:0% +in many other places. Um, so many other + + + align:start position:0% +in many other places. Um, so many other +countries in the world like a full-time + + align:start position:0% +countries in the world like a full-time + + + align:start position:0% +countries in the world like a full-time +licensed teacher would have more + + align:start position:0% +licensed teacher would have more + + + align:start position:0% +licensed teacher would have more +collaborative planning time, more + + align:start position:0% +collaborative planning time, more + + + align:start position:0% +collaborative planning time, more +grading time, other kinds of things like + + align:start position:0% +grading time, other kinds of things like + + + align:start position:0% +grading time, other kinds of things like +that. So, US teachers compared to their + + align:start position:0% +that. So, US teachers compared to their + + + align:start position:0% +that. So, US teachers compared to their +colleagues around the world are like + + align:start position:0% +colleagues around the world are like + + + align:start position:0% +colleagues around the world are like +behind the ball on having time anyway. + + align:start position:0% +behind the ball on having time anyway. + + + align:start position:0% +behind the ball on having time anyway. +Um, reducing workload is something they + + align:start position:0% +Um, reducing workload is something they + + + align:start position:0% +Um, reducing workload is something they +care about. What else do they care + + align:start position:0% +care about. What else do they care + + + align:start position:0% +care about. What else do they care +about? Like it has to spark the students + + align:start position:0% +about? Like it has to spark the students + + + align:start position:0% +about? Like it has to spark the students +interest. Good. So, they don't want kids + + align:start position:0% +interest. Good. So, they don't want kids + + + align:start position:0% +interest. Good. So, they don't want kids +to be bored. + + align:start position:0% +to be bored. + + + align:start position:0% +to be bored. +um that one of their one of their core + + align:start position:0% +um that one of their one of their core + + + align:start position:0% +um that one of their one of their core +interests is how am I going to keep + + align:start position:0% +interests is how am I going to keep + + + align:start position:0% +interests is how am I going to keep +these folks motivated? How am I going to + + align:start position:0% +these folks motivated? How am I going to + + + align:start position:0% +these folks motivated? How am I going to +keep them learning? What else do they + + align:start position:0% +keep them learning? What else do they + + + align:start position:0% +keep them learning? What else do they +care about? They care about it being of + + align:start position:0% +care about? They care about it being of + + + align:start position:0% +care about? They care about it being of +actually good quality. Okay, good. So, + + align:start position:0% +actually good quality. Okay, good. So, + + + align:start position:0% +actually good quality. Okay, good. So, +like it's really important that learning + + align:start position:0% +like it's really important that learning + + + align:start position:0% +like it's really important that learning +goes up, that quality is high, um that + + align:start position:0% +goes up, that quality is high, um that + + + align:start position:0% +goes up, that quality is high, um that +that you know that that uh teachers take + + align:start position:0% +that you know that that uh teachers take + + + align:start position:0% +that you know that that uh teachers take +their professionalism very very + + align:start position:0% +their professionalism very very + + + align:start position:0% +their professionalism very very +seriously and that you know and and + + align:start position:0% +seriously and that you know and and + + + align:start position:0% +seriously and that you know and and +they're held accountable in various + + align:start position:0% +they're held accountable in various + + + align:start position:0% +they're held accountable in various +kinds of ways. Um, and this could be + + align:start position:0% +kinds of ways. Um, and this could be + + + align:start position:0% +kinds of ways. Um, and this could be +different across different kinds of + + align:start position:0% +different across different kinds of + + + align:start position:0% +different across different kinds of +teachers. Um, so in the United States, + + align:start position:0% +teachers. Um, so in the United States, + + + align:start position:0% +teachers. Um, so in the United States, +we primaril we we we test in in certain + + align:start position:0% +we primaril we we we test in in certain + + + align:start position:0% +we primaril we we we test in in certain +kinds of ways. We test like way more + + align:start position:0% +kinds of ways. We test like way more + + + align:start position:0% +kinds of ways. We test like way more +than every other country does. There's + + align:start position:0% +than every other country does. There's + + + align:start position:0% +than every other country does. There's +no country that tests all of their + + align:start position:0% +no country that tests all of their + + + align:start position:0% +no country that tests all of their +students every year, third to eighth + + align:start position:0% +students every year, third to eighth + + + align:start position:0% +students every year, third to eighth +grade, in both reading and math. Most + + align:start position:0% +grade, in both reading and math. Most + + + align:start position:0% +grade, in both reading and math. Most +other countries are like if you test + + align:start position:0% +other countries are like if you test + + + align:start position:0% +other countries are like if you test +them in the third grade, you probably + + align:start position:0% +them in the third grade, you probably + + + align:start position:0% +them in the third grade, you probably +wait a couple years to like, you know, I + + align:start position:0% +wait a couple years to like, you know, I + + + align:start position:0% +wait a couple years to like, you know, I +mean, you give them like but you give + + align:start position:0% +mean, you give them like but you give + + + align:start position:0% +mean, you give them like but you give +them assessments or exams or whatever, + + align:start position:0% +them assessments or exams or whatever, + + + align:start position:0% +them assessments or exams or whatever, +but you don't give them like big + + align:start position:0% +but you don't give them like big + + + align:start position:0% +but you don't give them like big +national tests. Um and so if you are a + + align:start position:0% +national tests. Um and so if you are a + + + align:start position:0% +national tests. Um and so if you are a +teacher of reading or of math, um your + + align:start position:0% +teacher of reading or of math, um your + + + align:start position:0% +teacher of reading or of math, um your +test scores are scrutinized in a way + + align:start position:0% +test scores are scrutinized in a way + + + align:start position:0% +test scores are scrutinized in a way +that a science teacher, art teacher, a + + align:start position:0% +that a science teacher, art teacher, a + + + align:start position:0% +that a science teacher, art teacher, a +health teacher, other kinds of teachers + + align:start position:0% +health teacher, other kinds of teachers + + + align:start position:0% +health teacher, other kinds of teachers +are not similarly scrutinized. Um so + + align:start position:0% +are not similarly scrutinized. Um so + + + align:start position:0% +are not similarly scrutinized. Um so +within the you know there could be + + align:start position:0% +within the you know there could be + + + align:start position:0% +within the you know there could be +different kinds of incentives. One of + + align:start position:0% +different kinds of incentives. One of + + + align:start position:0% +different kinds of incentives. One of +the things I always enjoyed about being + + align:start position:0% +the things I always enjoyed about being + + + align:start position:0% +the things I always enjoyed about being +a history teacher is that there there + + align:start position:0% +a history teacher is that there there + + + align:start position:0% +a history teacher is that there there +were never really tests that I were + + align:start position:0% +were never really tests that I were + + + align:start position:0% +were never really tests that I were +preparing my students for. um in the + + align:start position:0% +preparing my students for. um in the + + + align:start position:0% +preparing my students for. um in the +same way I taught in private school, but + + align:start position:0% +same way I taught in private school, but + + + align:start position:0% +same way I taught in private school, but +even my math teacher colleagues like + + align:start position:0% +even my math teacher colleagues like + + + align:start position:0% +even my math teacher colleagues like +felt like they were preparing students + + align:start position:0% +felt like they were preparing students + + + align:start position:0% +felt like they were preparing students +for the SAT, for the APs, things like + + align:start position:0% +for the SAT, for the APs, things like + + + align:start position:0% +for the SAT, for the APs, things like +that. That was never really my concern. + + align:start position:0% +that. That was never really my concern. + + + align:start position:0% +that. That was never really my concern. +Um as a result, like I had to spend less + + align:start position:0% +Um as a result, like I had to spend less + + + align:start position:0% +Um as a result, like I had to spend less +time thinking to myself, this new thing + + align:start position:0% +time thinking to myself, this new thing + + + align:start position:0% +time thinking to myself, this new thing +I'm bringing in this classroom, is this + + align:start position:0% +I'm bringing in this classroom, is this + + + align:start position:0% +I'm bringing in this classroom, is this +going to prepare people for some kind of + + align:start position:0% +going to prepare people for some kind of + + + align:start position:0% +going to prepare people for some kind of +nearly universal testing experiences? + + align:start position:0% +nearly universal testing experiences? + + + align:start position:0% +nearly universal testing experiences? +Like my math teacher colleagues always + + align:start position:0% +Like my math teacher colleagues always + + + align:start position:0% +Like my math teacher colleagues always +had to be thinking about that. I could + + align:start position:0% +had to be thinking about that. I could + + + align:start position:0% +had to be thinking about that. I could +be like, well, you know, Tibetan + + align:start position:0% +be like, well, you know, Tibetan + + + align:start position:0% +be like, well, you know, Tibetan +Buddhism isn't on the test, but it's + + align:start position:0% +Buddhism isn't on the test, but it's + + + align:start position:0% +Buddhism isn't on the test, but it's +awesome. Let's study it. Um you know, so + + align:start position:0% +awesome. Let's study it. Um you know, so + + + align:start position:0% +awesome. Let's study it. Um you know, so +so that's different. Good. other kinds + + align:start position:0% +so that's different. Good. other kinds + + + align:start position:0% +so that's different. Good. other kinds +of things. Yeah. Tai and then Sabrina. + + align:start position:0% +of things. Yeah. Tai and then Sabrina. + + + align:start position:0% +of things. Yeah. Tai and then Sabrina. +Um accessibility and like inclusion. So + + align:start position:0% +Um accessibility and like inclusion. So + + + align:start position:0% +Um accessibility and like inclusion. So +making sure that like no one's left out + + align:start position:0% +making sure that like no one's left out + + + align:start position:0% +making sure that like no one's left out +from your diverse group of learners from + + align:start position:0% +from your diverse group of learners from + + + align:start position:0% +from your diverse group of learners from +any technology. + + align:start position:0% +any technology. + + + align:start position:0% +any technology. +Yeah. Um and that would not be a + + align:start position:0% +Yeah. Um and that would not be a + + + align:start position:0% +Yeah. Um and that would not be a +universal concern across these decades. + + align:start position:0% +universal concern across these decades. + + + align:start position:0% +universal concern across these decades. +um that you know um uh it would it would + + align:start position:0% +um that you know um uh it would it would + + + align:start position:0% +um that you know um uh it would it would +have been considered much more common to + + align:start position:0% +have been considered much more common to + + + align:start position:0% +have been considered much more common to +say like certain people have totally + + align:start position:0% +say like certain people have totally + + + align:start position:0% +say like certain people have totally +unsolvable learning disabilities and + + align:start position:0% +unsolvable learning disabilities and + + + align:start position:0% +unsolvable learning disabilities and +society should tend to their welfare in + + align:start position:0% +society should tend to their welfare in + + + align:start position:0% +society should tend to their welfare in +some other kind of way in the 30s and + + align:start position:0% +some other kind of way in the 30s and + + + align:start position:0% +some other kind of way in the 30s and +40s and 50s and then somewhere in the + + align:start position:0% +40s and 50s and then somewhere in the + + + align:start position:0% +40s and 50s and then somewhere in the +middle of the 20th century we passed um + + align:start position:0% +middle of the 20th century we passed um + + + align:start position:0% +middle of the 20th century we passed um +the Americans with Disabilities Act um + + align:start position:0% +the Americans with Disabilities Act um + + + align:start position:0% +the Americans with Disabilities Act um +which which totally transformed our + + align:start position:0% +which which totally transformed our + + + align:start position:0% +which which totally transformed our +thoughts and in fact you know created a + + align:start position:0% +thoughts and in fact you know created a + + + align:start position:0% +thoughts and in fact you know created a +federal right for people to have um you + + align:start position:0% +federal right for people to have um you + + + align:start position:0% +federal right for people to have um you +know a a way of being a fair and + + align:start position:0% +know a a way of being a fair and + + + align:start position:0% +know a a way of being a fair and +appropriate public education Um, and I + + align:start position:0% +appropriate public education Um, and I + + + align:start position:0% +appropriate public education Um, and I +would also just say educa, like as + + align:start position:0% +would also just say educa, like as + + + align:start position:0% +would also just say educa, like as +society has gotten more interested in + + align:start position:0% +society has gotten more interested in + + + align:start position:0% +society has gotten more interested in +values of inclusion generally, um, what + + align:start position:0% +values of inclusion generally, um, what + + + align:start position:0% +values of inclusion generally, um, what +people would have worried about with + + align:start position:0% +people would have worried about with + + + align:start position:0% +people would have worried about with +inclusion with personal computers in the + + align:start position:0% +inclusion with personal computers in the + + + align:start position:0% +inclusion with personal computers in the +1980s is very different for what they + + align:start position:0% +1980s is very different for what they + + + align:start position:0% +1980s is very different for what they +would be worried about with the + + align:start position:0% +would be worried about with the + + + align:start position:0% +would be worried about with the +computers that are getting in front of + + align:start position:0% +computers that are getting in front of + + + align:start position:0% +computers that are getting in front of +their students right now. That's a great + + align:start position:0% +their students right now. That's a great + + + align:start position:0% +their students right now. That's a great +one. I'm going to say being able to + + align:start position:0% +one. I'm going to say being able to + + + align:start position:0% +one. I'm going to say being able to +track student progress. + + align:start position:0% +track student progress. + + + align:start position:0% +track student progress. +Track + + align:start position:0% + + + + align:start position:0% + +progress + + align:start position:0% + + + + align:start position:0% + +assessment. Good. Yeah. I mean, actually + + align:start position:0% +assessment. Good. Yeah. I mean, actually + + + align:start position:0% +assessment. Good. Yeah. I mean, actually +interesting over this uh century, you + + align:start position:0% +interesting over this uh century, you + + + align:start position:0% +interesting over this uh century, you +know, um some of the earliest + + align:start position:0% +know, um some of the earliest + + + align:start position:0% +know, um some of the earliest +technologies had nothing to do with + + align:start position:0% +technologies had nothing to do with + + + align:start position:0% +technologies had nothing to do with +that, radio and film, but one of the + + align:start position:0% +that, radio and film, but one of the + + + align:start position:0% +that, radio and film, but one of the +very earliest ones you read about um + + align:start position:0% +very earliest ones you read about um + + + align:start position:0% +very earliest ones you read about um +physical teaching machines. Um uh and + + align:start position:0% +physical teaching machines. Um uh and + + + align:start position:0% +physical teaching machines. Um uh and +hopefully you got I mean you saw some + + align:start position:0% +hopefully you got I mean you saw some + + + align:start position:0% +hopefully you got I mean you saw some +pictures um I was just actually looking + + align:start position:0% +pictures um I was just actually looking + + + align:start position:0% +pictures um I was just actually looking +today there was a Sydney Pressie is one + + align:start position:0% +today there was a Sydney Pressie is one + + + align:start position:0% +today there was a Sydney Pressie is one +of the people who Audrey Waters writes + + align:start position:0% +of the people who Audrey Waters writes + + + align:start position:0% +of the people who Audrey Waters writes +about. Um and there's somebody on + + align:start position:0% +about. Um and there's somebody on + + + align:start position:0% +about. Um and there's somebody on +YouTube who had posted this like + + align:start position:0% +YouTube who had posted this like + + + align:start position:0% +YouTube who had posted this like +fabulous two-minute clip of him + + align:start position:0% +fabulous two-minute clip of him + + + align:start position:0% +fabulous two-minute clip of him +demonstrating one of his teacher + + align:start position:0% +demonstrating one of his teacher + + + align:start position:0% +demonstrating one of his teacher +machines and unfortunately that account + + align:start position:0% +machines and unfortunately that account + + + align:start position:0% +machines and unfortunately that account +was deleted before this year's class. Um + + align:start position:0% +was deleted before this year's class. Um + + + align:start position:0% +was deleted before this year's class. Um +may maybe I'll send you a version of it + + align:start position:0% +may maybe I'll send you a version of it + + + align:start position:0% +may maybe I'll send you a version of it +later. The only version of the video + + align:start position:0% +later. The only version of the video + + + align:start position:0% +later. The only version of the video +still exists is one in which a nand + + align:start position:0% +still exists is one in which a nand + + + align:start position:0% +still exists is one in which a nand +augur wall's voice is superimposed of + + align:start position:0% +augur wall's voice is superimposed of + + + align:start position:0% +augur wall's voice is superimposed of +it. Um, so somebody took an audio clip + + align:start position:0% +it. Um, so somebody took an audio clip + + + align:start position:0% +it. Um, so somebody took an audio clip +of Anand Agarwal talking about the + + align:start position:0% +of Anand Agarwal talking about the + + + align:start position:0% +of Anand Agarwal talking about the +capacities of Edex. Um, and played the + + align:start position:0% +capacities of Edex. Um, and played the + + + align:start position:0% +capacities of Edex. Um, and played the +audio over Sydney Pressy demonstrating + + align:start position:0% +audio over Sydney Pressy demonstrating + + + align:start position:0% +audio over Sydney Pressy demonstrating +the teaching machine. Um, and uh, it's a + + align:start position:0% +the teaching machine. Um, and uh, it's a + + + align:start position:0% +the teaching machine. Um, and uh, it's a +little too close for comfort even though + + align:start position:0% +little too close for comfort even though + + + align:start position:0% +little too close for comfort even though +it's a century apart. Um, but teaching + + align:start position:0% +it's a century apart. Um, but teaching + + + align:start position:0% +it's a century apart. Um, but teaching +machines, they were kind of like + + align:start position:0% +machines, they were kind of like + + + align:start position:0% +machines, they were kind of like +typewriters. Um, they had these four + + align:start position:0% +typewriters. Um, they had these four + + + align:start position:0% +typewriters. Um, they had these four +keys that were on them and so they would + + align:start position:0% +keys that were on them and so they would + + + align:start position:0% +keys that were on them and so they would +display one question at a time. Um, it + + align:start position:0% +display one question at a time. Um, it + + + align:start position:0% +display one question at a time. Um, it +was like pre-cantron technology, you + + align:start position:0% +was like pre-cantron technology, you + + + align:start position:0% +was like pre-cantron technology, you +know, and then there would be one of + + align:start position:0% +know, and then there would be one of + + + align:start position:0% +know, and then there would be one of +four possible answers. Um, in one of the + + align:start position:0% +four possible answers. Um, in one of the + + + align:start position:0% +four possible answers. Um, in one of the +earliest versions, it had a little like + + align:start position:0% +earliest versions, it had a little like + + + align:start position:0% +earliest versions, it had a little like +bank of mints in the back of them and so + + align:start position:0% +bank of mints in the back of them and so + + + align:start position:0% +bank of mints in the back of them and so +when you press the right button, like a + + align:start position:0% +when you press the right button, like a + + + align:start position:0% +when you press the right button, like a +little candy or something would roll out + + align:start position:0% +little candy or something would roll out + + + align:start position:0% +little candy or something would roll out +and give you like a little behaviorist + + align:start position:0% +and give you like a little behaviorist + + + align:start position:0% +and give you like a little behaviorist +positive, um, reinforcement kinds of + + align:start position:0% +positive, um, reinforcement kinds of + + + align:start position:0% +positive, um, reinforcement kinds of +things. Um, but one, you know, one of + + align:start position:0% +things. Um, but one, you know, one of + + + align:start position:0% +things. Um, but one, you know, one of +the main virtues of it was like, oh man, + + align:start position:0% +the main virtues of it was like, oh man, + + + align:start position:0% +the main virtues of it was like, oh man, +if we could get enough people these + + align:start position:0% +if we could get enough people these + + + align:start position:0% +if we could get enough people these +things, um, then we could like assess + + align:start position:0% +things, um, then we could like assess + + + align:start position:0% +things, um, then we could like assess +their progress almost constantly. We'd + + align:start position:0% +their progress almost constantly. We'd + + + align:start position:0% +their progress almost constantly. We'd +know exactly where they are. So, so this + + align:start position:0% +know exactly where they are. So, so this + + + align:start position:0% +know exactly where they are. So, so this +idea of track, you + + align:start position:0% +idea of track, you + + + align:start position:0% +idea of track, you +know, tracking student progress is + + align:start position:0% +know, tracking student progress is + + + align:start position:0% +know, tracking student progress is +something that's like particularly + + align:start position:0% +something that's like particularly + + + align:start position:0% +something that's like particularly +urgently concerned in our datadriven + + align:start position:0% +urgently concerned in our datadriven + + + align:start position:0% +urgently concerned in our datadriven +world, but was still something that + + align:start position:0% +world, but was still something that + + + align:start position:0% +world, but was still something that +people were interested in a century ago. + + align:start position:0% +people were interested in a century ago. + + + align:start position:0% +people were interested in a century ago. +Um, what are what are some of the I'll + + align:start position:0% +Um, what are what are some of the I'll + + + align:start position:0% +Um, what are what are some of the I'll +just put them under here. What are some + + align:start position:0% +just put them under here. What are some + + + align:start position:0% +just put them under here. What are some +of the the the would be disincentives + + align:start position:0% +of the the the would be disincentives + + + align:start position:0% +of the the the would be disincentives +for teachers? What are some things that + + align:start position:0% +for teachers? What are some things that + + + align:start position:0% +for teachers? What are some things that +if you were trying to get teachers to + + align:start position:0% +if you were trying to get teachers to + + + align:start position:0% +if you were trying to get teachers to +adopt new technologies would be the + + align:start position:0% +adopt new technologies would be the + + + align:start position:0% +adopt new technologies would be the +sorts of things that would be barriers + + align:start position:0% +sorts of things that would be barriers + + + align:start position:0% +sorts of things that would be barriers +for them? Complexity. Why complexity? A + + align:start position:0% +for them? Complexity. Why complexity? A + + + align:start position:0% +for them? Complexity. Why complexity? A +lot of there's there's uh some teachers + + align:start position:0% +lot of there's there's uh some teachers + + + align:start position:0% +lot of there's there's uh some teachers +who are more able to adapt to new + + align:start position:0% +who are more able to adapt to new + + + align:start position:0% +who are more able to adapt to new +technologies and some teachers who just + + align:start position:0% +technologies and some teachers who just + + + align:start position:0% +technologies and some teachers who just +cannot understand how certain + + align:start position:0% +cannot understand how certain + + + align:start position:0% +cannot understand how certain +technologies might work. Yeah. So I so I + + align:start position:0% +technologies might work. Yeah. So I so I + + + align:start position:0% +technologies might work. Yeah. So I so I +think I think that aptitude is right. I + + align:start position:0% +think I think that aptitude is right. I + + + align:start position:0% +think I think that aptitude is right. I +also many like if you go into teaching + + align:start position:0% +also many like if you go into teaching + + + align:start position:0% +also many like if you go into teaching +there probably probably two things that + + align:start position:0% +there probably probably two things that + + + align:start position:0% +there probably probably two things that +really drive you. One is you love the + + align:start position:0% +really drive you. One is you love the + + + align:start position:0% +really drive you. One is you love the +content that you teach. That's more true + + align:start position:0% +content that you teach. That's more true + + + align:start position:0% +content that you teach. That's more true +for secondary educators than for early + + align:start position:0% +for secondary educators than for early + + + align:start position:0% +for secondary educators than for early +elementary educators but probably true + + align:start position:0% +elementary educators but probably true + + + align:start position:0% +elementary educators but probably true +for them. And you probably love people. + + align:start position:0% +for them. And you probably love people. + + + align:start position:0% +for them. And you probably love people. +um very difficult to be a teacher if you + + align:start position:0% +um very difficult to be a teacher if you + + + align:start position:0% +um very difficult to be a teacher if you +don't find people especially young + + align:start position:0% +don't find people especially young + + + align:start position:0% +don't find people especially young +people pretty engaging. the kinds of + + align:start position:0% +people pretty engaging. the kinds of + + + align:start position:0% +people pretty engaging. the kinds of +folks who find people engaging, they + + align:start position:0% +folks who find people engaging, they + + + align:start position:0% +folks who find people engaging, they +might just find tech, it's not 100% + + align:start position:0% +might just find tech, it's not 100% + + + align:start position:0% +might just find tech, it's not 100% +overlap, but there just technology is + + align:start position:0% +overlap, but there just technology is + + + align:start position:0% +overlap, but there just technology is +less engaging. Like they didn't want to + + align:start position:0% +less engaging. Like they didn't want to + + + align:start position:0% +less engaging. Like they didn't want to +spend their life sitting in front of a + + align:start position:0% +spend their life sitting in front of a + + + align:start position:0% +spend their life sitting in front of a +computer typing itself. They wanted to + + align:start position:0% +computer typing itself. They wanted to + + + align:start position:0% +computer typing itself. They wanted to +be interacting with people. + + align:start position:0% +be interacting with people. + + + align:start position:0% +be interacting with people. +Um, but the other thing I would say is + + align:start position:0% +Um, but the other thing I would say is + + + align:start position:0% +Um, but the other thing I would say is +that there are many educators who spend + + align:start position:0% +that there are many educators who spend + + + align:start position:0% +that there are many educators who spend +a lot of time polishing their craft and + + align:start position:0% +a lot of time polishing their craft and + + + align:start position:0% +a lot of time polishing their craft and +are good at teaching the way they're + + align:start position:0% +are good at teaching the way they're + + + align:start position:0% +are good at teaching the way they're +teaching right now and have been + + align:start position:0% +teaching right now and have been + + + align:start position:0% +teaching right now and have been +teaching for the last decade. And so + + align:start position:0% +teaching for the last decade. And so + + + align:start position:0% +teaching for the last decade. And so +when they see a new piece of technology + + align:start position:0% +when they see a new piece of technology + + + align:start position:0% +when they see a new piece of technology +come in, they're thinking to themselves, + + align:start position:0% +come in, they're thinking to themselves, + + + align:start position:0% +come in, they're thinking to themselves, +is this thing really going to be better + + align:start position:0% +is this thing really going to be better + + + align:start position:0% +is this thing really going to be better +than the thing that I've been doing and + + align:start position:0% +than the thing that I've been doing and + + + align:start position:0% +than the thing that I've been doing and +got good at for a while, um, you know, + + align:start position:0% +got good at for a while, um, you know, + + + align:start position:0% +got good at for a while, um, you know, +what am I g what am I I'm going to have + + align:start position:0% +what am I g what am I I'm going to have + + + align:start position:0% +what am I g what am I I'm going to have +to lose something when I integrate this + + align:start position:0% +to lose something when I integrate this + + + align:start position:0% +to lose something when I integrate this +new thing? Like like any technology + + align:start position:0% +new thing? Like like any technology + + + align:start position:0% +new thing? Like like any technology +adoption involves loss. Any change + + align:start position:0% +adoption involves loss. Any change + + + align:start position:0% +adoption involves loss. Any change +involves loss. You got to give something + + align:start position:0% +involves loss. You got to give something + + + align:start position:0% +involves loss. You got to give something +up. Um, I think giving up it may be + + align:start position:0% +up. Um, I think giving up it may be + + + align:start position:0% +up. Um, I think giving up it may be +pretty good. Um, a lot I think a lot of + + align:start position:0% +pretty good. Um, a lot I think a lot of + + + align:start position:0% +pretty good. Um, a lot I think a lot of +people think that older teachers because + + align:start position:0% +people think that older teachers because + + + align:start position:0% +people think that older teachers because +are are less likely to adopt + + align:start position:0% +are are less likely to adopt + + + align:start position:0% +are are less likely to adopt +technologies because they're not + + align:start position:0% +technologies because they're not + + + align:start position:0% +technologies because they're not +technology fluent. But having worked + + align:start position:0% +technology fluent. But having worked + + + align:start position:0% +technology fluent. But having worked +with many many teachers, I'm really + + align:start position:0% +with many many teachers, I'm really + + + align:start position:0% +with many many teachers, I'm really +convinced that there's no relationship + + align:start position:0% +convinced that there's no relationship + + + align:start position:0% +convinced that there's no relationship +between age and technology adoption. + + align:start position:0% +between age and technology adoption. + + + align:start position:0% +between age and technology adoption. +There are young teachers that are super + + align:start position:0% +There are young teachers that are super + + + align:start position:0% +There are young teachers that are super +interested and there are young teachers + + align:start position:0% +interested and there are young teachers + + + align:start position:0% +interested and there are young teachers +who hate it. There are old teachers who + + align:start position:0% +who hate it. There are old teachers who + + + align:start position:0% +who hate it. There are old teachers who +are like, I'm pretty good at what I do. + + align:start position:0% +are like, I'm pretty good at what I do. + + + align:start position:0% +are like, I'm pretty good at what I do. +And there are old teachers who are old + + align:start position:0% +And there are old teachers who are old + + + align:start position:0% +And there are old teachers who are old +teachers because they've spent the last + + align:start position:0% +teachers because they've spent the last + + + align:start position:0% +teachers because they've spent the last +20 years going, it's really fun to try + + align:start position:0% +20 years going, it's really fun to try + + + align:start position:0% +20 years going, it's really fun to try +new things. It's really fun to try to + + align:start position:0% +new things. It's really fun to try to + + + align:start position:0% +new things. It's really fun to try to +get better. What was one of your + + align:start position:0% +get better. What was one of your + + + align:start position:0% +get better. What was one of your +disincentives, Sabrina? uh student + + align:start position:0% +disincentives, Sabrina? uh student + + + align:start position:0% +disincentives, Sabrina? uh student +distraction. + + align:start position:0% +distraction. + + + align:start position:0% +distraction. +Great. And obviously some of these + + align:start position:0% +Great. And obviously some of these + + + align:start position:0% +Great. And obviously some of these +technologies are more akin to that than + + align:start position:0% +technologies are more akin to that than + + + align:start position:0% +technologies are more akin to that than +others. Like if you're playing a film + + align:start position:0% +others. Like if you're playing a film + + + align:start position:0% +others. Like if you're playing a film +strip or something like that, like you + + align:start position:0% +strip or something like that, like you + + + align:start position:0% +strip or something like that, like you +probably have kids attention or things + + align:start position:0% +probably have kids attention or things + + + align:start position:0% +probably have kids attention or things +like that. Um but uh certainly as we get + + align:start position:0% +like that. Um but uh certainly as we get + + + align:start position:0% +like that. Um but uh certainly as we get +into computers, any anything in which + + align:start position:0% +into computers, any anything in which + + + align:start position:0% +into computers, any anything in which +you know the the attention is where + + align:start position:0% +you know the the attention is where + + + align:start position:0% +you know the the attention is where +where each student is responsible for + + align:start position:0% +where each student is responsible for + + + align:start position:0% +where each student is responsible for +their own attention um is something that + + align:start position:0% +their own attention um is something that + + + align:start position:0% +their own attention um is something that +that uh can can raise concerns for + + align:start position:0% +that uh can can raise concerns for + + + align:start position:0% +that uh can can raise concerns for +teachers because kids like to be attend + + align:start position:0% +teachers because kids like to be attend + + + align:start position:0% +teachers because kids like to be attend +to all kinds of things. What what other + + align:start position:0% +to all kinds of things. What what other + + + align:start position:0% +to all kinds of things. What what other +things would be disincentives like + + align:start position:0% +things would be disincentives like + + + align:start position:0% +things would be disincentives like +teacher displacement like they feel like + + align:start position:0% +teacher displacement like they feel like + + + align:start position:0% +teacher displacement like they feel like +they're being replaced? Yep. Um so + + align:start position:0% +they're being replaced? Yep. Um so + + + align:start position:0% +they're being replaced? Yep. Um so +teachers are a profession um you know + + align:start position:0% +teachers are a profession um you know + + + align:start position:0% +teachers are a profession um you know +that that protects their job security + + align:start position:0% +that that protects their job security + + + align:start position:0% +that that protects their job security +with a license and things like that like + + align:start position:0% +with a license and things like that like + + + align:start position:0% +with a license and things like that like +lots of other professions do like + + align:start position:0% +lots of other professions do like + + + align:start position:0% +lots of other professions do like +doctors and pharmacists and lawyers and + + align:start position:0% +doctors and pharmacists and lawyers and + + + align:start position:0% +doctors and pharmacists and lawyers and +all kinds of people. Um and uh yeah and + + align:start position:0% +all kinds of people. Um and uh yeah and + + + align:start position:0% +all kinds of people. Um and uh yeah and +yeah but most professionals are not + + align:start position:0% +yeah but most professionals are not + + + align:start position:0% +yeah but most professionals are not +super enthusiastic about technology that + + align:start position:0% +super enthusiastic about technology that + + + align:start position:0% +super enthusiastic about technology that +has the capacity to replace the + + align:start position:0% +has the capacity to replace the + + + align:start position:0% +has the capacity to replace the +functions that they're doing. + + align:start position:0% +functions that they're doing. + + + align:start position:0% +functions that they're doing. +Um, good. Let's think about some of + + align:start position:0% +Um, good. Let's think about some of + + + align:start position:0% +Um, good. Let's think about some of +these other um, so, so this is a good + + align:start position:0% +these other um, so, so this is a good + + + align:start position:0% +these other um, so, so this is a good +one. So, so again, we could think about + + align:start position:0% +one. So, so again, we could think about + + + align:start position:0% +one. So, so again, we could think about +anytime a new technology is being + + align:start position:0% +anytime a new technology is being + + + align:start position:0% +anytime a new technology is being +introduced, is it going to reduce + + align:start position:0% +introduced, is it going to reduce + + + align:start position:0% +introduced, is it going to reduce +workload? Is it going to spark interest? + + align:start position:0% +workload? Is it going to spark interest? + + + align:start position:0% +workload? Is it going to spark interest? +Will it spark interest in the first + + align:start position:0% +Will it spark interest in the first + + + align:start position:0% +Will it spark interest in the first +three weeks of this new technology being + + align:start position:0% +three weeks of this new technology being + + + align:start position:0% +three weeks of this new technology being +here, will it spark interest two years + + align:start position:0% +here, will it spark interest two years + + + align:start position:0% +here, will it spark interest two years +after the technology has been + + align:start position:0% +after the technology has been + + + align:start position:0% +after the technology has been +introduced? Is it going to be of high + + align:start position:0% +introduced? Is it going to be of high + + + align:start position:0% +introduced? Is it going to be of high +quality? Do I have control over the + + align:start position:0% +quality? Do I have control over the + + + align:start position:0% +quality? Do I have control over the +quality? Um, accessible inclusion, is it + + align:start position:0% +quality? Um, accessible inclusion, is it + + + align:start position:0% +quality? Um, accessible inclusion, is it +going to improve learning? Will it be + + align:start position:0% +going to improve learning? Will it be + + + align:start position:0% +going to improve learning? Will it be +able to track assessment? Is it too + + align:start position:0% +able to track assessment? Is it too + + + align:start position:0% +able to track assessment? Is it too +complex? Will it like distract my + + align:start position:0% +complex? Will it like distract my + + + align:start position:0% +complex? Will it like distract my +students? Is it going to displace + + align:start position:0% +students? Is it going to displace + + + align:start position:0% +students? Is it going to displace +essential functions that I perform? Um, + + align:start position:0% +essential functions that I perform? Um, + + + align:start position:0% +essential functions that I perform? Um, +those are like that is a good set of + + align:start position:0% +those are like that is a good set of + + + align:start position:0% +those are like that is a good set of +questions that you could ask, you know, + + align:start position:0% +questions that you could ask, you know, + + + align:start position:0% +questions that you could ask, you know, +that Cuban does ask in some ways of + + align:start position:0% +that Cuban does ask in some ways of + + + align:start position:0% +that Cuban does ask in some ways of +radio and film and television and + + align:start position:0% +radio and film and television and + + + align:start position:0% +radio and film and television and +teaching machines and computers. Um, and + + align:start position:0% +teaching machines and computers. Um, and + + + align:start position:0% +teaching machines and computers. Um, and +you could ask them of AI and Khan + + align:start position:0% +you could ask them of AI and Khan + + + align:start position:0% +you could ask them of AI and Khan +Academy and I civics and anything else + + align:start position:0% +Academy and I civics and anything else + + + align:start position:0% +Academy and I civics and anything else +that comes along. Like these are all + + align:start position:0% +that comes along. Like these are all + + + align:start position:0% +that comes along. Like these are all +still good questions to ask. Um, let's + + align:start position:0% +still good questions to ask. Um, let's + + + align:start position:0% +still good questions to ask. Um, let's +try to hit now a bunch of these other + + align:start position:0% +try to hit now a bunch of these other + + + align:start position:0% +try to hit now a bunch of these other +stakeholders. Um, who are who are some + + align:start position:0% +stakeholders. Um, who are who are some + + + align:start position:0% +stakeholders. Um, who are who are some +of the stakeholders that surprised you? + + align:start position:0% +of the stakeholders that surprised you? + + + align:start position:0% +of the stakeholders that surprised you? +Who are the ones that you were like, + + align:start position:0% +Who are the ones that you were like, + + + align:start position:0% +Who are the ones that you were like, +"Whoa, I wouldn't have thought of this + + align:start position:0% +"Whoa, I wouldn't have thought of this + + + align:start position:0% +"Whoa, I wouldn't have thought of this +in terms of education + + align:start position:0% + + + + align:start position:0% + +technology, weird ones or unique ones." + + align:start position:0% +technology, weird ones or unique ones." + + + align:start position:0% +technology, weird ones or unique ones." +I mean, I thought like my group was the + + align:start position:0% +I mean, I thought like my group was the + + + align:start position:0% +I mean, I thought like my group was the +teacher machines and it was like the + + align:start position:0% +teacher machines and it was like the + + + align:start position:0% +teacher machines and it was like the +psychologists that like come up with the + + align:start position:0% +psychologists that like come up with the + + + align:start position:0% +psychologists that like come up with the +ideas um that go into how these + + align:start position:0% +ideas um that go into how these + + + align:start position:0% +ideas um that go into how these +technologies are or what they're based + + align:start position:0% +technologies are or what they're based + + + align:start position:0% +technologies are or what they're based +on. Um like I guess I never just never + + align:start position:0% +on. Um like I guess I never just never + + + align:start position:0% +on. Um like I guess I never just never +really thought like oh like you know it + + align:start position:0% +really thought like oh like you know it + + + align:start position:0% +really thought like oh like you know it +is the people who like thought of + + align:start position:0% +is the people who like thought of + + + align:start position:0% +is the people who like thought of +constructivism and like situated + + align:start position:0% +constructivism and like situated + + + align:start position:0% +constructivism and like situated +learning that has then sparked this + + align:start position:0% +learning that has then sparked this + + + align:start position:0% +learning that has then sparked this +interest in everything else. Um and so + + align:start position:0% +interest in everything else. Um and so + + + align:start position:0% +interest in everything else. Um and so +it's like people have ideas but all of + + align:start position:0% +it's like people have ideas but all of + + + align:start position:0% +it's like people have ideas but all of +that initially stemmed from these like + + align:start position:0% +that initially stemmed from these like + + + align:start position:0% +that initially stemmed from these like +two thoughts of learning. Good. Yeah. So + + align:start position:0% +two thoughts of learning. Good. Yeah. So + + + align:start position:0% +two thoughts of learning. Good. Yeah. So +so so people have ideas about what good + + align:start position:0% +so so people have ideas about what good + + + align:start position:0% +so so people have ideas about what good +teaching and learning should be like. + + align:start position:0% +teaching and learning should be like. + + + align:start position:0% +teaching and learning should be like. +Those ideas are in some ways they seem + + align:start position:0% +Those ideas are in some ways they seem + + + align:start position:0% +Those ideas are in some ways they seem +pretty universal because we can find + + align:start position:0% +pretty universal because we can find + + + align:start position:0% +pretty universal because we can find +them going back through history but + + align:start position:0% +them going back through history but + + + align:start position:0% +them going back through history but +they're als they're always being + + align:start position:0% +they're als they're always being + + + align:start position:0% +they're als they're always being +reinterpreted updated things like that. + + align:start position:0% +reinterpreted updated things like that. + + + align:start position:0% +reinterpreted updated things like that. +Um Sydney Pressie is in this moment + + align:start position:0% +Um Sydney Pressie is in this moment + + + align:start position:0% +Um Sydney Pressie is in this moment +where behaviorism is an incredibly + + align:start position:0% +where behaviorism is an incredibly + + + align:start position:0% +where behaviorism is an incredibly +prominent set of you know set of ideas. + + align:start position:0% +prominent set of you know set of ideas. + + + align:start position:0% +prominent set of you know set of ideas. +This behaviorism you're probably all + + align:start position:0% +This behaviorism you're probably all + + + align:start position:0% +This behaviorism you're probably all +familiar with of you know you uh punish + + align:start position:0% +familiar with of you know you uh punish + + + align:start position:0% +familiar with of you know you uh punish +people when they do things wrong and you + + align:start position:0% +people when they do things wrong and you + + + align:start position:0% +people when they do things wrong and you +reward them when you do things right and + + align:start position:0% +reward them when you do things right and + + + align:start position:0% +reward them when you do things right and +you condition their behavior that way. + + align:start position:0% +you condition their behavior that way. + + + align:start position:0% +you condition their behavior that way. +Um and so he creates a physical machine + + align:start position:0% +Um and so he creates a physical machine + + + align:start position:0% +Um and so he creates a physical machine +that embodies those ideas. Um there you + + align:start position:0% +that embodies those ideas. Um there you + + + align:start position:0% +that embodies those ideas. Um there you +know and then you know Seymour Papert + + align:start position:0% +know and then you know Seymour Papert + + + align:start position:0% +know and then you know Seymour Papert +will come along um and be like oh man + + align:start position:0% +will come along um and be like oh man + + + align:start position:0% +will come along um and be like oh man +why can't we learn math the way that + + align:start position:0% +why can't we learn math the way that + + + align:start position:0% +why can't we learn math the way that +like kids who go to visit France learn + + align:start position:0% +like kids who go to visit France learn + + + align:start position:0% +like kids who go to visit France learn +French? um why can't we make a thing + + align:start position:0% +French? um why can't we make a thing + + + align:start position:0% +French? um why can't we make a thing +which is math land? I bet logo could be + + align:start position:0% +which is math land? I bet logo could be + + + align:start position:0% +which is math land? I bet logo could be +like math land. He has a set he have a + + align:start position:0% +like math land. He has a set he have a + + + align:start position:0% +like math land. He has a set he have a +set of ideas about what good teaching + + align:start position:0% +set of ideas about what good teaching + + + align:start position:0% +set of ideas about what good teaching +and learning looks like and he + + align:start position:0% +and learning looks like and he + + + align:start position:0% +and learning looks like and he +incorporates those ideas. Um and they + + align:start position:0% +incorporates those ideas. Um and they + + + align:start position:0% +incorporates those ideas. Um and they +and people become partisans of these + + align:start position:0% +and people become partisans of these + + + align:start position:0% +and people become partisans of these +ideas. Um you know probably the most + + align:start position:0% +ideas. Um you know probably the most + + + align:start position:0% +ideas. Um you know probably the most +prominent partisan of education + + align:start position:0% +prominent partisan of education + + + align:start position:0% +prominent partisan of education +technology in the United States today is + + align:start position:0% +technology in the United States today is + + + align:start position:0% +technology in the United States today is +Salon. Um who's someone who like had a + + align:start position:0% +Salon. Um who's someone who like had a + + + align:start position:0% +Salon. Um who's someone who like had a +very particular idea like a like clear + + align:start position:0% +very particular idea like a like clear + + + align:start position:0% +very particular idea like a like clear +vision of what personalized learning + + align:start position:0% +vision of what personalized learning + + + align:start position:0% +vision of what personalized learning +would look like. you know, he had he had + + align:start position:0% +would look like. you know, he had he had + + + align:start position:0% +would look like. you know, he had he had +I don't know if you know about his his + + align:start position:0% +I don't know if you know about his his + + + align:start position:0% +I don't know if you know about his his +personal experience, but he was like a + + align:start position:0% +personal experience, but he was like a + + + align:start position:0% +personal experience, but he was like a +hedge fund person or something like that + + align:start position:0% +hedge fund person or something like that + + + align:start position:0% +hedge fund person or something like that +and his uh um niece was having trouble + + align:start position:0% +and his uh um niece was having trouble + + + align:start position:0% +and his uh um niece was having trouble +with math and he started tutoring his + + align:start position:0% +with math and he started tutoring his + + + align:start position:0% +with math and he started tutoring his +niece in math and he put like did it + + align:start position:0% +niece in math and he put like did it + + + align:start position:0% +niece in math and he put like did it +over videos and so he put the videos + + align:start position:0% +over videos and so he put the videos + + + align:start position:0% +over videos and so he put the videos +online, people started watching them. He + + align:start position:0% +online, people started watching them. He + + + align:start position:0% +online, people started watching them. He +go, "Wow, what if every person could + + align:start position:0% +go, "Wow, what if every person could + + + align:start position:0% +go, "Wow, what if every person could +have this little like personalized + + align:start position:0% +have this little like personalized + + + align:start position:0% +have this little like personalized +tutor?" Um what if each person could + + align:start position:0% +tutor?" Um what if each person could + + + align:start position:0% +tutor?" Um what if each person could +sort of study math at their own + + align:start position:0% +sort of study math at their own + + + align:start position:0% +sort of study math at their own +individual pace? Um, and then he built + + align:start position:0% +individual pace? Um, and then he built + + + align:start position:0% +individual pace? Um, and then he built +this whole enterprise and continues to, + + align:start position:0% +this whole enterprise and continues to, + + + align:start position:0% +this whole enterprise and continues to, +you know, he he's incredibly + + align:start position:0% +you know, he he's incredibly + + + align:start position:0% +you know, he he's incredibly +enthusiastic about AI right now because + + align:start position:0% +enthusiastic about AI right now because + + + align:start position:0% +enthusiastic about AI right now because +like, oh man, instead of just having me + + align:start position:0% +like, oh man, instead of just having me + + + align:start position:0% +like, oh man, instead of just having me +record um a tutor for each person, like + + align:start position:0% +record um a tutor for each person, like + + + align:start position:0% +record um a tutor for each person, like +what if the GPT can like generate + + align:start position:0% +what if the GPT can like generate + + + align:start position:0% +what if the GPT can like generate +personalized text related to each + + align:start position:0% +personalized text related to each + + + align:start position:0% +personalized text related to each +individual person or something like + + align:start position:0% +individual person or something like + + + align:start position:0% +individual person or something like +that. Um, and those ideas, you know, + + align:start position:0% +that. Um, and those ideas, you know, + + + align:start position:0% +that. Um, and those ideas, you know, +they're it's it's not like they're just + + align:start position:0% +they're it's it's not like they're just + + + align:start position:0% +they're it's it's not like they're just +dropped in the world. They're advocated + + align:start position:0% +dropped in the world. They're advocated + + + align:start position:0% +dropped in the world. They're advocated +for. Um, did you all see the New York + + align:start position:0% +for. Um, did you all see the New York + + + align:start position:0% +for. Um, did you all see the New York +Time was it New York Times or Washington + + align:start position:0% +Time was it New York Times or Washington + + + align:start position:0% +Time was it New York Times or Washington +Post? Somebody wrote an op-ed about um + + align:start position:0% +Post? Somebody wrote an op-ed about um + + + align:start position:0% +Post? Somebody wrote an op-ed about um +about Salon and AI. It was either in the + + align:start position:0% +about Salon and AI. It was either in the + + + align:start position:0% +about Salon and AI. It was either in the +Washington Post or the New York Times, + + align:start position:0% +Washington Post or the New York Times, + + + align:start position:0% +Washington Post or the New York Times, +but it was basically something like this + + align:start position:0% +but it was basically something like this + + + align:start position:0% +but it was basically something like this +is the first AI that your kid will love + + align:start position:0% +is the first AI that your kid will love + + + align:start position:0% +is the first AI that your kid will love +or something like that. And it's + + align:start position:0% +or something like that. And it's + + + align:start position:0% +or something like that. And it's +basically just a sort of celebratory + + align:start position:0% +basically just a sort of celebratory + + + align:start position:0% +basically just a sort of celebratory +piece of of Kot MIGO. Um good. So, so + + align:start position:0% +piece of of Kot MIGO. Um good. So, so + + + align:start position:0% +piece of of Kot MIGO. Um good. So, so +that's an unusual group, you know, and + + align:start position:0% +that's an unusual group, you know, and + + + align:start position:0% +that's an unusual group, you know, and +and those groups um they I mean today + + align:start position:0% +and those groups um they I mean today + + + align:start position:0% +and those groups um they I mean today +they like, you know, like Saw Khan goes + + align:start position:0% +they like, you know, like Saw Khan goes + + + align:start position:0% +they like, you know, like Saw Khan goes +on the Today Show and tells people what + + align:start position:0% +on the Today Show and tells people what + + + align:start position:0% +on the Today Show and tells people what +he thinks. He goes to investor + + align:start position:0% +he thinks. He goes to investor + + + align:start position:0% +he thinks. He goes to investor +conferences and tells people what he + + align:start position:0% +conferences and tells people what he + + + align:start position:0% +conferences and tells people what he +thinks. He goes to schools, you know, + + align:start position:0% +thinks. He goes to schools, you know, + + + align:start position:0% +thinks. He goes to schools, you know, +Harvard and MIT bringing him in every + + align:start position:0% +Harvard and MIT bringing him in every + + + align:start position:0% +Harvard and MIT bringing him in every +couple years and things like that. So + + align:start position:0% +couple years and things like that. So + + + align:start position:0% +couple years and things like that. So +these folks advocate for their ideas. Um + + align:start position:0% +these folks advocate for their ideas. Um + + + align:start position:0% +these folks advocate for their ideas. Um +they're not, you know, the ideas the + + align:start position:0% +they're not, you know, the ideas the + + + align:start position:0% +they're not, you know, the ideas the +ideas don't fall from the sky. There's a + + align:start position:0% +ideas don't fall from the sky. There's a + + + align:start position:0% +ideas don't fall from the sky. There's a +stakeholder who is advancing those + + align:start position:0% +stakeholder who is advancing those + + + align:start position:0% +stakeholder who is advancing those +ideas. Who are some who are some other + + align:start position:0% +ideas. Who are some who are some other + + + align:start position:0% +ideas. Who are some who are some other +stakeholders that seem important? Um, I + + align:start position:0% +stakeholders that seem important? Um, I + + + align:start position:0% +stakeholders that seem important? Um, I +thought it was weird that you could + + align:start position:0% +thought it was weird that you could + + + align:start position:0% +thought it was weird that you could +think about like manufacturers and I + + align:start position:0% +think about like manufacturers and I + + + align:start position:0% +think about like manufacturers and I +mean like like the people who produce + + align:start position:0% +mean like like the people who produce + + + align:start position:0% +mean like like the people who produce +transistors which is like TSMC and ASML + + align:start position:0% +transistors which is like TSMC and ASML + + + align:start position:0% +transistors which is like TSMC and ASML +because if a bunch of schools across + + align:start position:0% +because if a bunch of schools across + + + align:start position:0% +because if a bunch of schools across +America all of a sudden need like + + align:start position:0% +America all of a sudden need like + + + align:start position:0% +America all of a sudden need like +thousands and thousands of iPads and you + + align:start position:0% +thousands and thousands of iPads and you + + + align:start position:0% +thousands and thousands of iPads and you +have like this big backlog request on + + align:start position:0% +have like this big backlog request on + + + align:start position:0% +have like this big backlog request on +like M2 chips or whatever is in them + + align:start position:0% +like M2 chips or whatever is in them + + + align:start position:0% +like M2 chips or whatever is in them +right now and then someone like TSMC the + + align:start position:0% +right now and then someone like TSMC the + + + align:start position:0% +right now and then someone like TSMC the +only people who really produce + + align:start position:0% +only people who really produce + + + align:start position:0% +only people who really produce +transistors has this huge float and they + + align:start position:0% +transistors has this huge float and they + + + align:start position:0% +transistors has this huge float and they +make a lot of money. Yeah. Yeah. that + + align:start position:0% +make a lot of money. Yeah. Yeah. that + + + align:start position:0% +make a lot of money. Yeah. Yeah. that +that that that people become, you know, + + align:start position:0% +that that that people become, you know, + + + align:start position:0% +that that that people become, you know, +that those folks then organize + + align:start position:0% +that those folks then organize + + + align:start position:0% +that those folks then organize +themselves into trade groups um and they + + align:start position:0% +themselves into trade groups um and they + + + align:start position:0% +themselves into trade groups um and they +go to, you know, they they how do they + + align:start position:0% +go to, you know, they they how do they + + + align:start position:0% +go to, you know, they they how do they +how do they advance their interests? + + align:start position:0% +how do they advance their interests? + + + align:start position:0% +how do they advance their interests? +They do things like um give some of + + align:start position:0% +They do things like um give some of + + + align:start position:0% +They do things like um give some of +their materials away for schools, + + align:start position:0% +their materials away for schools, + + + align:start position:0% +their materials away for schools, +demonstration, they create training + + align:start position:0% +demonstration, they create training + + + align:start position:0% +demonstration, they create training +programs for their materials and share + + align:start position:0% +programs for their materials and share + + + align:start position:0% +programs for their materials and share +them. Um they have sales and marketing + + align:start position:0% +them. Um they have sales and marketing + + + align:start position:0% +them. Um they have sales and marketing +people that go around and get people + + align:start position:0% +people that go around and get people + + + align:start position:0% +people that go around and get people +advanced about that. Um they like + + align:start position:0% +advanced about that. Um they like + + + align:start position:0% +advanced about that. Um they like +sponsor conferences. they, you know, + + align:start position:0% +sponsor conferences. they, you know, + + + align:start position:0% +sponsor conferences. they, you know, +what maybe that they're not even + + align:start position:0% +what maybe that they're not even + + + align:start position:0% +what maybe that they're not even +directly advertising for. They're + + align:start position:0% +directly advertising for. They're + + + align:start position:0% +directly advertising for. They're +they're just, you know, their presence + + align:start position:0% +they're just, you know, their presence + + + align:start position:0% +they're just, you know, their presence +to try to encourage teachers and other + + align:start position:0% +to try to encourage teachers and other + + + align:start position:0% +to try to encourage teachers and other +sorts of groups to to be behind it. Um, + + align:start position:0% +sorts of groups to to be behind it. Um, + + + align:start position:0% +sorts of groups to to be behind it. Um, +you know, uh, we spend an enormous + + align:start position:0% +you know, uh, we spend an enormous + + + align:start position:0% +you know, uh, we spend an enormous +amount of money on education every year + + align:start position:0% +amount of money on education every year + + + align:start position:0% +amount of money on education every year +in the United States and lot, you know, + + align:start position:0% +in the United States and lot, you know, + + + align:start position:0% +in the United States and lot, you know, +the the biggest chunk of that money goes + + align:start position:0% +the the biggest chunk of that money goes + + + align:start position:0% +the the biggest chunk of that money goes +to pay the salaries of the people who do + + align:start position:0% +to pay the salaries of the people who do + + + align:start position:0% +to pay the salaries of the people who do +stuff and another big chunk of that + + align:start position:0% +stuff and another big chunk of that + + + align:start position:0% +stuff and another big chunk of that +money goes to heating and air + + align:start position:0% +money goes to heating and air + + + align:start position:0% +money goes to heating and air +conditioning, you know, for which there + + align:start position:0% +conditioning, you know, for which there + + + align:start position:0% +conditioning, you know, for which there +are people who are selling those things. + + align:start position:0% +are people who are selling those things. + + + align:start position:0% +are people who are selling those things. +Um but you know basically the third + + align:start position:0% +Um but you know basically the third + + + align:start position:0% +Um but you know basically the third +biggest bucket after those two is the + + align:start position:0% +biggest bucket after those two is the + + + align:start position:0% +biggest bucket after those two is the +stuff we buy in schools to help people + + align:start position:0% +stuff we buy in schools to help people + + + align:start position:0% +stuff we buy in schools to help people +learn. Um and so um uh yeah there there + + align:start position:0% +learn. Um and so um uh yeah there there + + + align:start position:0% +learn. Um and so um uh yeah there there +are advocates who are you know the folks + + align:start position:0% +are advocates who are you know the folks + + + align:start position:0% +are advocates who are you know the folks +who are not neutral in these things. Um + + align:start position:0% +who are not neutral in these things. Um + + + align:start position:0% +who are not neutral in these things. Um +there are ways you know Apple computer + + align:start position:0% +there are ways you know Apple computer + + + align:start position:0% +there are ways you know Apple computer +has been particularly prominent over the + + align:start position:0% +has been particularly prominent over the + + + align:start position:0% +has been particularly prominent over the +last bunch of years and trying to craft + + align:start position:0% +last bunch of years and trying to craft + + + align:start position:0% +last bunch of years and trying to craft +a vision of itself as a company um that + + align:start position:0% +a vision of itself as a company um that + + + align:start position:0% +a vision of itself as a company um that +has a particular role inside colleges, + + align:start position:0% +has a particular role inside colleges, + + + align:start position:0% +has a particular role inside colleges, +universities, schools those kinds of + + align:start position:0% +universities, schools those kinds of + + + align:start position:0% +universities, schools those kinds of +things. + + align:start position:0% +things. + + + align:start position:0% +things. +I think something that surprised me, but + + align:start position:0% +I think something that surprised me, but + + + align:start position:0% +I think something that surprised me, but +maybe it's not that surprising, was like + + align:start position:0% +maybe it's not that surprising, was like + + + align:start position:0% +maybe it's not that surprising, was like +government government as a whole and + + align:start position:0% +government government as a whole and + + + align:start position:0% +government government as a whole and +like eludism between governments because + + align:start position:0% +like eludism between governments because + + + align:start position:0% +like eludism between governments because +uh in the class we took last semester + + align:start position:0% +uh in the class we took last semester + + + align:start position:0% +uh in the class we took last semester +like in education. We talked a lot about + + align:start position:0% +like in education. We talked a lot about + + + align:start position:0% +like in education. We talked a lot about +like Americanism and how like it's so + + align:start position:0% +like Americanism and how like it's so + + + align:start position:0% +like Americanism and how like it's so +linked with education and I know it's + + align:start position:0% +linked with education and I know it's + + + align:start position:0% +linked with education and I know it's +such a big thing to be like oh like this + + align:start position:0% +such a big thing to be like oh like this + + + align:start position:0% +such a big thing to be like oh like this +country has like the biggest amount like + + align:start position:0% +country has like the biggest amount like + + + align:start position:0% +country has like the biggest amount like +the highest SAT score on average or like + + align:start position:0% +the highest SAT score on average or like + + + align:start position:0% +the highest SAT score on average or like +this many people academy or something + + align:start position:0% +this many people academy or something + + + align:start position:0% +this many people academy or something +like that. So sometimes it really is + + align:start position:0% +like that. So sometimes it really is + + + align:start position:0% +like that. So sometimes it really is +just like governments competing against + + align:start position:0% +just like governments competing against + + + align:start position:0% +just like governments competing against +each other and trying to see like who's + + align:start position:0% +each other and trying to see like who's + + + align:start position:0% +each other and trying to see like who's +the best of the best. Great. And in the + + align:start position:0% +the best of the best. Great. And in the + + + align:start position:0% +the best of the best. Great. And in the +United States when we talk about + + align:start position:0% +United States when we talk about + + + align:start position:0% +United States when we talk about +government actors, what are all the + + align:start position:0% +government actors, what are all the + + + align:start position:0% +government actors, what are all the +different possible government actors we + + align:start position:0% +different possible government actors we + + + align:start position:0% +different possible government actors we +might be thinking about? + + align:start position:0% +might be thinking about? + + + align:start position:0% +might be thinking about? +Education. So there's a US Department of + + align:start position:0% +Education. So there's a US Department of + + + align:start position:0% +Education. So there's a US Department of +Education. Who else is there? + + align:start position:0% +Education. Who else is there? + + + align:start position:0% +Education. Who else is there? +So local boards of education. So there's + + align:start position:0% +So local boards of education. So there's + + + align:start position:0% +So local boards of education. So there's +local boards of education. So a very un + + align:start position:0% +local boards of education. So a very un + + + align:start position:0% +local boards of education. So a very un +unusual thing about the United States + + align:start position:0% +unusual thing about the United States + + + align:start position:0% +unusual thing about the United States +Department of Education is it is or the + + align:start position:0% +Department of Education is it is or the + + + align:start position:0% +Department of Education is it is or the +United States education system is it's + + align:start position:0% +United States education system is it's + + + align:start position:0% +United States education system is it's +extremely decentralized. There are + + align:start position:0% +extremely decentralized. There are + + + align:start position:0% +extremely decentralized. There are +130,000 schools and there are 13,000 + + align:start position:0% +130,000 schools and there are 13,000 + + + align:start position:0% +130,000 schools and there are 13,000 +school districts. The modal elected + + align:start position:0% +school districts. The modal elected + + + align:start position:0% +school districts. The modal elected +official in the United States is a + + align:start position:0% +official in the United States is a + + + align:start position:0% +official in the United States is a +schoolboard member. There are more if if + + align:start position:0% +schoolboard member. There are more if if + + + align:start position:0% +schoolboard member. There are more if if +you are if you're an elected official in + + align:start position:0% +you are if you're an elected official in + + + align:start position:0% +you are if you're an elected official in +the United States, the thing you are + + align:start position:0% +the United States, the thing you are + + + align:start position:0% +the United States, the thing you are +most likely to be is a schoolboard + + align:start position:0% +most likely to be is a schoolboard + + + align:start position:0% +most likely to be is a schoolboard +member. Um and you know um schoolboard + + align:start position:0% +member. Um and you know um schoolboard + + + align:start position:0% +member. Um and you know um schoolboard +members are interesting stakeholders. + + align:start position:0% +members are interesting stakeholders. + + + align:start position:0% +members are interesting stakeholders. +They are um well and they range from + + align:start position:0% +They are um well and they range from + + + align:start position:0% +They are um well and they range from +community to communities. In lots of + + align:start position:0% +community to communities. In lots of + + + align:start position:0% +community to communities. In lots of +communities, they're just like a + + align:start position:0% +communities, they're just like a + + + align:start position:0% +communities, they're just like a +community member who's particularly + + align:start position:0% +community member who's particularly + + + align:start position:0% +community member who's particularly +interested in education. Um but there + + align:start position:0% +interested in education. Um but there + + + align:start position:0% +interested in education. Um but there +are also um people who are looking to um + + align:start position:0% +are also um people who are looking to um + + + align:start position:0% +are also um people who are looking to um +you know, it's an entry point for people + + align:start position:0% +you know, it's an entry point for people + + + align:start position:0% +you know, it's an entry point for people +who are interested in political careers. + + align:start position:0% +who are interested in political careers. + + + align:start position:0% +who are interested in political careers. +Lots of people who you are schoolboard + + align:start position:0% +Lots of people who you are schoolboard + + + align:start position:0% +Lots of people who you are schoolboard +members go to be on state reps and other + + align:start position:0% +members go to be on state reps and other + + + align:start position:0% +members go to be on state reps and other +kinds of things like that. This is a + + align:start position:0% +kinds of things like that. This is a + + + align:start position:0% +kinds of things like that. This is a +particularly um sort of fakened moment + + align:start position:0% +particularly um sort of fakened moment + + + align:start position:0% +particularly um sort of fakened moment +for people who are politically who are + + align:start position:0% +for people who are politically who are + + + align:start position:0% +for people who are politically who are +who are politically ambitious to pursue + + align:start position:0% +who are politically ambitious to pursue + + + align:start position:0% +who are politically ambitious to pursue +those ambitious uh through the school + + align:start position:0% +those ambitious uh through the school + + + align:start position:0% +those ambitious uh through the school +system. Um especially uh in the American + + align:start position:0% +system. Um especially uh in the American + + + align:start position:0% +system. Um especially uh in the American +right um where where reform of schools + + align:start position:0% +right um where where reform of schools + + + align:start position:0% +right um where where reform of schools +has become like a way to get kind of + + align:start position:0% +has become like a way to get kind of + + + align:start position:0% +has become like a way to get kind of +attention within the political party and + + align:start position:0% +attention within the political party and + + + align:start position:0% +attention within the political party and +things like that. Um, and uh, and yeah, + + align:start position:0% +things like that. Um, and uh, and yeah, + + + align:start position:0% +things like that. Um, and uh, and yeah, +there's all there's all kinds of towns + + align:start position:0% +there's all there's all kinds of towns + + + align:start position:0% +there's all there's all kinds of towns +across the country where, you know, and + + align:start position:0% +across the country where, you know, and + + + align:start position:0% +across the country where, you know, and +I think you get some of this is like + + align:start position:0% +I think you get some of this is like + + + align:start position:0% +I think you get some of this is like +some school board is like, you know, + + align:start position:0% +some school board is like, you know, + + + align:start position:0% +some school board is like, you know, +what would be really great is film + + align:start position:0% +what would be really great is film + + + align:start position:0% +what would be really great is film +strips. Like, let's go big on film + + align:start position:0% +strips. Like, let's go big on film + + + align:start position:0% +strips. Like, let's go big on film +strips. Um, you know, what would be + + align:start position:0% +strips. Um, you know, what would be + + + align:start position:0% +strips. Um, you know, what would be +really great is like closed circuit + + align:start position:0% +really great is like closed circuit + + + align:start position:0% +really great is like closed circuit +television. Um, wouldn't that be a + + align:start position:0% +television. Um, wouldn't that be a + + + align:start position:0% +television. Um, wouldn't that be a +useful thing to have? You know, and so + + align:start position:0% +useful thing to have? You know, and so + + + align:start position:0% +useful thing to have? You know, and so +it's it's not even like it's not the + + align:start position:0% +it's it's not even like it's not the + + + align:start position:0% +it's it's not even like it's not the +teachers, it's not the superintendent, + + align:start position:0% +teachers, it's not the superintendent, + + + align:start position:0% +teachers, it's not the superintendent, +it's not the people who are sort of in + + align:start position:0% +it's not the people who are sort of in + + + align:start position:0% +it's not the people who are sort of in +the schools, it's like some community + + align:start position:0% +the schools, it's like some community + + + align:start position:0% +the schools, it's like some community +members who are like, "Let's do it." + + align:start position:0% +members who are like, "Let's do it." + + + align:start position:0% +members who are like, "Let's do it." +um uh you know I in uh in the United + + align:start position:0% +um uh you know I in uh in the United + + + align:start position:0% +um uh you know I in uh in the United +States today there probably two versions + + align:start position:0% +States today there probably two versions + + + align:start position:0% +States today there probably two versions +of that is there are definitely school + + align:start position:0% +of that is there are definitely school + + + align:start position:0% +of that is there are definitely school +boards whose identity is sort of shaped + + align:start position:0% +boards whose identity is sort of shaped + + + align:start position:0% +boards whose identity is sort of shaped +around like being a cutting edge school + + align:start position:0% +around like being a cutting edge school + + + align:start position:0% +around like being a cutting edge school +like in a bunch of the affluent suburban + + align:start position:0% +like in a bunch of the affluent suburban + + + align:start position:0% +like in a bunch of the affluent suburban +towns around Boston you know like Wells + + align:start position:0% +towns around Boston you know like Wells + + + align:start position:0% +towns around Boston you know like Wells +Lee Newton like they want to be thought + + align:start position:0% +Lee Newton like they want to be thought + + + align:start position:0% +Lee Newton like they want to be thought +of as having like really great cutting + + align:start position:0% +of as having like really great cutting + + + align:start position:0% +of as having like really great cutting +edge forward thinking schools you know + + align:start position:0% +edge forward thinking schools you know + + + align:start position:0% +edge forward thinking schools you know +Newton spent $200 million or something + + align:start position:0% +Newton spent $200 million or something + + + align:start position:0% +Newton spent $200 million or something +like that on the last high school that + + align:start position:0% +like that on the last high school that + + + align:start position:0% +like that on the last high school that +they built um and so it can be you know + + align:start position:0% +they built um and so it can be you know + + + align:start position:0% +they built um and so it can be you know +a way they become a schoolboard member + + align:start position:0% +a way they become a schoolboard member + + + align:start position:0% +a way they become a schoolboard member +is like I'm going to help the school + + align:start position:0% +is like I'm going to help the school + + + align:start position:0% +is like I'm going to help the school +system modernize and embrace technology + + align:start position:0% +system modernize and embrace technology + + + align:start position:0% +system modernize and embrace technology +and things like that. There can also be + + align:start position:0% +and things like that. There can also be + + + align:start position:0% +and things like that. There can also be +the opposite. There can also be people + + align:start position:0% +the opposite. There can also be people + + + align:start position:0% +the opposite. There can also be people +who come in um the most common is like + + align:start position:0% +who come in um the most common is like + + + align:start position:0% +who come in um the most common is like +people who work for the technology + + align:start position:0% +people who work for the technology + + + align:start position:0% +people who work for the technology +industry who are like you have no idea + + align:start position:0% +industry who are like you have no idea + + + align:start position:0% +industry who are like you have no idea +how much surveillance is built into this + + align:start position:0% +how much surveillance is built into this + + + align:start position:0% +how much surveillance is built into this +technology. Um all the time when I talk + + align:start position:0% +technology. Um all the time when I talk + + + align:start position:0% +technology. Um all the time when I talk +to you know principles or + + align:start position:0% +to you know principles or + + + align:start position:0% +to you know principles or +superintendents who are being like we're + + align:start position:0% +superintendents who are being like we're + + + align:start position:0% +superintendents who are being like we're +kind of having a hard time you know + + align:start position:0% +kind of having a hard time you know + + + align:start position:0% +kind of having a hard time you know +helping parents understand why these + + align:start position:0% +helping parents understand why these + + + align:start position:0% +helping parents understand why these +things would be useful. It's like + + align:start position:0% +things would be useful. It's like + + + align:start position:0% +things would be useful. It's like +someone who works for Google or + + align:start position:0% +someone who works for Google or + + + align:start position:0% +someone who works for Google or +Microsoft or something like that, you + + align:start position:0% +Microsoft or something like that, you + + + align:start position:0% +Microsoft or something like that, you +know, who like who knows the + + align:start position:0% +know, who like who knows the + + + align:start position:0% +know, who like who knows the +surveillance capacity of these tools and + + align:start position:0% +surveillance capacity of these tools and + + + align:start position:0% +surveillance capacity of these tools and +is concerned about it. Um, yeah, I just + + align:start position:0% +is concerned about it. Um, yeah, I just + + + align:start position:0% +is concerned about it. Um, yeah, I just +kind of like an anecdote that I used to + + align:start position:0% +kind of like an anecdote that I used to + + + align:start position:0% +kind of like an anecdote that I used to +work in edtech and educational + + align:start position:0% +work in edtech and educational + + + align:start position:0% +work in edtech and educational +publishing and I worked on mostly + + align:start position:0% +publishing and I worked on mostly + + + align:start position:0% +publishing and I worked on mostly +products for the state of Florida and + + align:start position:0% +products for the state of Florida and + + + align:start position:0% +products for the state of Florida and +like really showed how much power some + + align:start position:0% +like really showed how much power some + + + align:start position:0% +like really showed how much power some +of these districts have like the because + + align:start position:0% +of these districts have like the because + + + align:start position:0% +of these districts have like the because +the school board would make a decision + + align:start position:0% +the school board would make a decision + + + align:start position:0% +the school board would make a decision +like every several times or one or two + + align:start position:0% +like every several times or one or two + + + align:start position:0% +like every several times or one or two +districts in Florida would some say they + + align:start position:0% +districts in Florida would some say they + + + align:start position:0% +districts in Florida would some say they +need something and that would change the + + align:start position:0% +need something and that would change the + + + align:start position:0% +need something and that would change the +entire road map for a product that's + + align:start position:0% +entire road map for a product that's + + + align:start position:0% +entire road map for a product that's +used nationally. So it's like you have a + + align:start position:0% +used nationally. So it's like you have a + + + align:start position:0% +used nationally. So it's like you have a +couple people in Florida who are like we + + align:start position:0% +couple people in Florida who are like we + + + align:start position:0% +couple people in Florida who are like we +really need this thing and suddenly it's + + align:start position:0% +really need this thing and suddenly it's + + + align:start position:0% +really need this thing and suddenly it's +like kids in Arkansas are also are + + align:start position:0% +like kids in Arkansas are also are + + + align:start position:0% +like kids in Arkansas are also are +learning differently. So I would this is + + align:start position:0% +learning differently. So I would this is + + + align:start position:0% +learning differently. So I would this is +in this is definitely still true. It's + + align:start position:0% +in this is definitely still true. It's + + + align:start position:0% +in this is definitely still true. It's +breaking down a little bit because of + + align:start position:0% +breaking down a little bit because of + + + align:start position:0% +breaking down a little bit because of +the capacity for sort of a web + + align:start position:0% +the capacity for sort of a web + + + align:start position:0% +the capacity for sort of a web +publishing and custom publication but + + align:start position:0% +publishing and custom publication but + + + align:start position:0% +publishing and custom publication but +for a big chunk of what you might I + + align:start position:0% +for a big chunk of what you might I + + + align:start position:0% +for a big chunk of what you might I +don't know the latter third of the 20th + + align:start position:0% +don't know the latter third of the 20th + + + align:start position:0% +don't know the latter third of the 20th +century the first 10 years of the 21st + + align:start position:0% +century the first 10 years of the 21st + + + align:start position:0% +century the first 10 years of the 21st +century um basic you know like somebody + + align:start position:0% +century um basic you know like somebody + + + align:start position:0% +century um basic you know like somebody +publishers would publish a US history + + align:start position:0% +publishers would publish a US history + + + align:start position:0% +publishers would publish a US history +book um how do they decide what to make + + align:start position:0% +book um how do they decide what to make + + + align:start position:0% +book um how do they decide what to make +of a US history book um you say well + + align:start position:0% +of a US history book um you say well + + + align:start position:0% +of a US history book um you say well +like what are the most important states + + align:start position:0% +like what are the most important states + + + align:start position:0% +like what are the most important states +to sell this history book + + align:start position:0% +to sell this history book + + + align:start position:0% +to sell this history book +in Florida is one of them what are the + + align:start position:0% +in Florida is one of them what are the + + + align:start position:0% +in Florida is one of them what are the +other ones You can name them. + + align:start position:0% +other ones You can name them. + + + align:start position:0% +other ones You can name them. +California, + + align:start position:0% +California, + + + align:start position:0% +California, +Texas, New York, California, Texas, New + + align:start position:0% +Texas, New York, California, Texas, New + + + align:start position:0% +Texas, New York, California, Texas, New +York, Florida. Um those are like four of + + align:start position:0% +York, Florida. Um those are like four of + + + align:start position:0% +York, Florida. Um those are like four of +the most important states just by + + align:start position:0% +the most important states just by + + + align:start position:0% +the most important states just by +population. Um so now you got to think + + align:start position:0% +population. Um so now you got to think + + + align:start position:0% +population. Um so now you got to think +about like the the standards of th like + + align:start position:0% +about like the the standards of th like + + + align:start position:0% +about like the the standards of th like +the his every state has standards. The + + align:start position:0% +the his every state has standards. The + + + align:start position:0% +the his every state has standards. The +history standards of those four states + + align:start position:0% +history standards of those four states + + + align:start position:0% +history standards of those four states +are more important than the history + + align:start position:0% +are more important than the history + + + align:start position:0% +are more important than the history +standards of Maine and North Dakota. Um + + align:start position:0% +standards of Maine and North Dakota. Um + + + align:start position:0% +standards of Maine and North Dakota. Um +and as like political things come up + + align:start position:0% +and as like political things come up + + + align:start position:0% +and as like political things come up +around you know history is where this + + align:start position:0% +around you know history is where this + + + align:start position:0% +around you know history is where this +happens pretty frequently but it happens + + align:start position:0% +happens pretty frequently but it happens + + + align:start position:0% +happens pretty frequently but it happens +in math and reading and other things + + align:start position:0% +in math and reading and other things + + + align:start position:0% +in math and reading and other things +too. Um yeah actually I I used to do + + align:start position:0% +too. Um yeah actually I I used to do + + + align:start position:0% +too. Um yeah actually I I used to do +consulting for uh um uh history for + + align:start position:0% +consulting for uh um uh history for + + + align:start position:0% +consulting for uh um uh history for +publishers of history textbooks and once + + align:start position:0% +publishers of history textbooks and once + + + align:start position:0% +publishers of history textbooks and once +I saw the sort of matrix where it was + + align:start position:0% +I saw the sort of matrix where it was + + + align:start position:0% +I saw the sort of matrix where it was +like it was like all the possible topics + + align:start position:0% +like it was like all the possible topics + + + align:start position:0% +like it was like all the possible topics +along the the columns and all of the + + align:start position:0% +along the the columns and all of the + + + align:start position:0% +along the the columns and all of the +states along the rows and like x's of + + align:start position:0% +states along the rows and like x's of + + + align:start position:0% +states along the rows and like x's of +like where all the topics get t you know + + align:start position:0% +like where all the topics get t you know + + + align:start position:0% +like where all the topics get t you know +the I mean the other thing is for like + + align:start position:0% +the I mean the other thing is for like + + + align:start position:0% +the I mean the other thing is for like +there'll be a huge you know group of + + align:start position:0% +there'll be a huge you know group of + + + align:start position:0% +there'll be a huge you know group of +Polish immigrants that come to some + + align:start position:0% +Polish immigrants that come to some + + + align:start position:0% +Polish immigrants that come to some +state and like they won't see Polish + + align:start position:0% +state and like they won't see Polish + + + align:start position:0% +state and like they won't see Polish +people represented in their textbooks + + align:start position:0% +people represented in their textbooks + + + align:start position:0% +people represented in their textbooks +and so they'll be like we're, you know, + + align:start position:0% +and so they'll be like we're, you know, + + + align:start position:0% +and so they'll be like we're, you know, +we're only going to adopt books that + + align:start position:0% +we're only going to adopt books that + + + align:start position:0% +we're only going to adopt books that +like talk about the importance of Polish + + align:start position:0% +like talk about the importance of Polish + + + align:start position:0% +like talk about the importance of Polish +Americans in the history. You the + + align:start position:0% +Americans in the history. You the + + + align:start position:0% +Americans in the history. You the +publishing companies are like, "All + + align:start position:0% +publishing companies are like, "All + + + align:start position:0% +publishing companies are like, "All +right, add the Polish and then, you + + align:start position:0% +right, add the Polish and then, you + + + align:start position:0% +right, add the Polish and then, you +know, but then the Italians do it and + + align:start position:0% +know, but then the Italians do it and + + + align:start position:0% +know, but then the Italians do it and +the Cambodian do everybody else do it + + align:start position:0% +the Cambodian do everybody else do it + + + align:start position:0% +the Cambodian do everybody else do it +and the textbooks get, you know, that's + + align:start position:0% +and the textbooks get, you know, that's + + + align:start position:0% +and the textbooks get, you know, that's +why when you picked up your 800 pound um + + align:start position:0% +why when you picked up your 800 pound um + + + align:start position:0% +why when you picked up your 800 pound um +history textbook, it was full of like + + align:start position:0% +history textbook, it was full of like + + + align:start position:0% +history textbook, it was full of like +all these like weird little um bits and + + align:start position:0% +all these like weird little um bits and + + + align:start position:0% +all these like weird little um bits and +pieces and things like that. So yeah, + + align:start position:0% +pieces and things like that. So yeah, + + + align:start position:0% +pieces and things like that. So yeah, +these these state level I mean here's + + align:start position:0% +these these state level I mean here's + + + align:start position:0% +these these state level I mean here's +another like tiny feature of this but + + align:start position:0% +another like tiny feature of this but + + + align:start position:0% +another like tiny feature of this but +ends up being important. Um there are + + align:start position:0% +ends up being important. Um there are + + + align:start position:0% +ends up being important. Um there are +some states mostly in the south where + + align:start position:0% +some states mostly in the south where + + + align:start position:0% +some states mostly in the south where +material adoptions happen centrally or + + align:start position:0% +material adoptions happen centrally or + + + align:start position:0% +material adoptions happen centrally or +have some kind of centralized function. + + align:start position:0% +have some kind of centralized function. + + + align:start position:0% +have some kind of centralized function. +Um so Texas, Florida, they have state + + align:start position:0% +Um so Texas, Florida, they have state + + + align:start position:0% +Um so Texas, Florida, they have state +level boards that say you can only adopt + + align:start position:0% +level boards that say you can only adopt + + + align:start position:0% +level boards that say you can only adopt +books that pass these boards. + + align:start position:0% +books that pass these boards. + + + align:start position:0% +books that pass these boards. +Massachusetts is a huge local control + + align:start position:0% +Massachusetts is a huge local control + + + align:start position:0% +Massachusetts is a huge local control +state. Um the school districts in + + align:start position:0% +state. Um the school districts in + + + align:start position:0% +state. Um the school districts in +Massachusetts will go bonkers if the + + align:start position:0% +Massachusetts will go bonkers if the + + + align:start position:0% +Massachusetts will go bonkers if the +state tried to tell them which textbooks + + align:start position:0% +state tried to tell them which textbooks + + + align:start position:0% +state tried to tell them which textbooks +they could or could not use. You know, + + align:start position:0% +they could or could not use. You know, + + + align:start position:0% +they could or could not use. You know, +there'd be like another revolution. you + + align:start position:0% +there'd be like another revolution. you + + + align:start position:0% +there'd be like another revolution. you +know, one if buy land, two if buy um you + + align:start position:0% +know, one if buy land, two if buy um you + + + align:start position:0% +know, one if buy land, two if buy um you +know, C-class Mercedes or whatever it + + align:start position:0% +know, C-class Mercedes or whatever it + + + align:start position:0% +know, C-class Mercedes or whatever it +is. Um and uh they they just wouldn't + + align:start position:0% +is. Um and uh they they just wouldn't + + + align:start position:0% +is. Um and uh they they just wouldn't +allow it. But it means that those states + + align:start position:0% +allow it. But it means that those states + + + align:start position:0% +allow it. But it means that those states +that have this sort of centralized + + align:start position:0% +that have this sort of centralized + + + align:start position:0% +that have this sort of centralized +function actually end up having more + + align:start position:0% +function actually end up having more + + + align:start position:0% +function actually end up having more +influence over the publishers because + + align:start position:0% +influence over the publishers because + + + align:start position:0% +influence over the publishers because +they say, "Look, you want to sell a book + + align:start position:0% +they say, "Look, you want to sell a book + + + align:start position:0% +they say, "Look, you want to sell a book +here?" You know, and now it's not just a + + align:start position:0% +here?" You know, and now it's not just a + + + align:start position:0% +here?" You know, and now it's not just a +book, now it's a web program or things + + align:start position:0% +book, now it's a web program or things + + + align:start position:0% +book, now it's a web program or things +like that. Now, the thing that sort of + + align:start position:0% +like that. Now, the thing that sort of + + + align:start position:0% +like that. Now, the thing that sort of +like is breaking away some of that + + align:start position:0% +like is breaking away some of that + + + align:start position:0% +like is breaking away some of that +monopoly, although also causing kind of + + align:start position:0% +monopoly, although also causing kind of + + + align:start position:0% +monopoly, although also causing kind of +problems is, you know, states can say + + align:start position:0% +problems is, you know, states can say + + + align:start position:0% +problems is, you know, states can say +like, okay, we want to, you know, we're + + align:start position:0% +like, okay, we want to, you know, we're + + + align:start position:0% +like, okay, we want to, you know, we're +going to pass all these laws that b that + + align:start position:0% +going to pass all these laws that b that + + + align:start position:0% +going to pass all these laws that b that +have the effect of like way ramping down + + align:start position:0% +have the effect of like way ramping down + + + align:start position:0% +have the effect of like way ramping down +the teaching of black history. Um, and + + align:start position:0% +the teaching of black history. Um, and + + + align:start position:0% +the teaching of black history. Um, and +you know, publishers can be like, all + + align:start position:0% +you know, publishers can be like, all + + + align:start position:0% +you know, publishers can be like, all +right, well, your web version of that + + align:start position:0% +right, well, your web version of that + + + align:start position:0% +right, well, your web version of that +will delete this and this and this and + + align:start position:0% +will delete this and this and this and + + + align:start position:0% +will delete this and this and this and +this, but you know, over in New York or + + align:start position:0% +this, but you know, over in New York or + + + align:start position:0% +this, but you know, over in New York or +California and liberal states, you can + + align:start position:0% +California and liberal states, you can + + + align:start position:0% +California and liberal states, you can +have all that kind of stuff in there. + + align:start position:0% +have all that kind of stuff in there. + + + align:start position:0% +have all that kind of stuff in there. +Yeah. Khil. Yeah. And kind of like uh uh + + align:start position:0% +Yeah. Khil. Yeah. And kind of like uh uh + + + align:start position:0% +Yeah. Khil. Yeah. And kind of like uh uh +going off of that like the political + + align:start position:0% +going off of that like the political + + + align:start position:0% +going off of that like the political +platforms play a like a large role in + + align:start position:0% +platforms play a like a large role in + + + align:start position:0% +platforms play a like a large role in +most of these places in the US that's + + align:start position:0% +most of these places in the US that's + + + align:start position:0% +most of these places in the US that's +very like very much there but as an + + align:start position:0% +very like very much there but as an + + + align:start position:0% +very like very much there but as an +example from my own country like there + + align:start position:0% +example from my own country like there + + + align:start position:0% +example from my own country like there +at every public school they have like a + + align:start position:0% +at every public school they have like a + + + align:start position:0% +at every public school they have like a +speaker system like at the start of the + + align:start position:0% +speaker system like at the start of the + + + align:start position:0% +speaker system like at the start of the +school specifically because they want to + + align:start position:0% +school specifically because they want to + + + align:start position:0% +school specifically because they want to +play the national anthem. That's + + align:start position:0% +play the national anthem. That's + + + align:start position:0% +play the national anthem. That's +something they did really early. The + + align:start position:0% +something they did really early. The + + + align:start position:0% +something they did really early. The +kids have to uh to do it and to like oh + + align:start position:0% +kids have to uh to do it and to like oh + + + align:start position:0% +kids have to uh to do it and to like oh +there's so much like technology that + + align:start position:0% +there's so much like technology that + + + align:start position:0% +there's so much like technology that +just one thing why is this the only + + align:start position:0% +just one thing why is this the only + + + align:start position:0% +just one thing why is this the only +piece of there is like some kind of + + align:start position:0% +piece of there is like some kind of + + + align:start position:0% +piece of there is like some kind of +incentive they want to build with like + + align:start position:0% +incentive they want to build with like + + + align:start position:0% +incentive they want to build with like +you know kind of political motive. And + + align:start position:0% +you know kind of political motive. And + + + align:start position:0% +you know kind of political motive. And +then does does the does that broadcast + + align:start position:0% +then does does the does that broadcast + + + align:start position:0% +then does does the does that broadcast +system be used at other parts of the day + + align:start position:0% +system be used at other parts of the day + + + align:start position:0% +system be used at other parts of the day +as well or this only gets used at the + + align:start position:0% +as well or this only gets used at the + + + align:start position:0% +as well or this only gets used at the +start of the school where the national + + align:start position:0% +start of the school where the national + + + align:start position:0% +start of the school where the national +anthem have like some like some kids uh + + align:start position:0% +anthem have like some like some kids uh + + + align:start position:0% +anthem have like some like some kids uh +every like classroom does like a session + + align:start position:0% +every like classroom does like a session + + + align:start position:0% +every like classroom does like a session +where they just like do like some + + align:start position:0% +where they just like do like some + + + align:start position:0% +where they just like do like some +religious stuff uh some like Arabic + + align:start position:0% +religious stuff uh some like Arabic + + + align:start position:0% +religious stuff uh some like Arabic +poems some like fun facts and then just + + align:start position:0% +poems some like fun facts and then just + + + align:start position:0% +poems some like fun facts and then just +that but that's mostly just I I love + + align:start position:0% +that but that's mostly just I I love + + + align:start position:0% +that but that's mostly just I I love +that. I think that's a fabulous example. + + align:start position:0% +that. I think that's a fabulous example. + + + align:start position:0% +that. I think that's a fabulous example. +So, so the the whatever the state + + align:start position:0% +So, so the the whatever the state + + + align:start position:0% +So, so the the whatever the state +government is like the state is in the + + align:start position:0% +government is like the state is in the + + + align:start position:0% +government is like the state is in the +nation the nation state government um + + align:start position:0% +nation the nation state government um + + + align:start position:0% +nation the nation state government um +says every school must broadcast the + + align:start position:0% +says every school must broadcast the + + + align:start position:0% +says every school must broadcast the +national anthem every day. Um every + + align:start position:0% +national anthem every day. Um every + + + align:start position:0% +national anthem every day. Um every +single school in the country then has to + + align:start position:0% +single school in the country then has to + + + align:start position:0% +single school in the country then has to +build a technology infrastructure that + + align:start position:0% +build a technology infrastructure that + + + align:start position:0% +build a technology infrastructure that +allows that to happen and then once that + + align:start position:0% +allows that to happen and then once that + + + align:start position:0% +allows that to happen and then once that +technology infrastructure is there it + + align:start position:0% +technology infrastructure is there it + + + align:start position:0% +technology infrastructure is there it +can be used in other kinds of ways as + + align:start position:0% +can be used in other kinds of ways as + + + align:start position:0% +can be used in other kinds of ways as +well or not used or other kinds of + + align:start position:0% +well or not used or other kinds of + + + align:start position:0% +well or not used or other kinds of +things like that. Um you can find + + align:start position:0% +things like that. Um you can find + + + align:start position:0% +things like that. Um you can find +national examples of this in other kinds + + align:start position:0% +national examples of this in other kinds + + + align:start position:0% +national examples of this in other kinds +of ways. You know, one of the most + + align:start position:0% +of ways. You know, one of the most + + + align:start position:0% +of ways. You know, one of the most +interesting countries right now um for + + align:start position:0% +interesting countries right now um for + + + align:start position:0% +interesting countries right now um for +education policy makers to watch is + + align:start position:0% +education policy makers to watch is + + + align:start position:0% +education policy makers to watch is +Estonia. Um about every decade, like + + align:start position:0% +Estonia. Um about every decade, like + + + align:start position:0% +Estonia. Um about every decade, like +some country that people aren't really + + align:start position:0% +some country that people aren't really + + + align:start position:0% +some country that people aren't really +paying attention to um gets really good + + align:start position:0% +paying attention to um gets really good + + + align:start position:0% +paying attention to um gets really good +international test scores. Um so + + align:start position:0% +international test scores. Um so + + + align:start position:0% +international test scores. Um so +Singapore was it for a while, Finland + + align:start position:0% +Singapore was it for a while, Finland + + + align:start position:0% +Singapore was it for a while, Finland +was it for a while, people are obsessed + + align:start position:0% +was it for a while, people are obsessed + + + align:start position:0% +was it for a while, people are obsessed +with Finland for a while, and Estonia is + + align:start position:0% +with Finland for a while, and Estonia is + + + align:start position:0% +with Finland for a while, and Estonia is +kind of last like who are you people and + + align:start position:0% +kind of last like who are you people and + + + align:start position:0% +kind of last like who are you people and +why like why are you so good at reading? + + align:start position:0% +why like why are you so good at reading? + + + align:start position:0% +why like why are you so good at reading? +Um and uh Estonia is very famous for it + + align:start position:0% +Um and uh Estonia is very famous for it + + + align:start position:0% +Um and uh Estonia is very famous for it +sometimes it's called Estonia. um their + + align:start position:0% +sometimes it's called Estonia. um their + + + align:start position:0% +sometimes it's called Estonia. um their +government has really embraced the + + align:start position:0% +government has really embraced the + + + align:start position:0% +government has really embraced the +internet um in a very centralized kind + + align:start position:0% +internet um in a very centralized kind + + + align:start position:0% +internet um in a very centralized kind +of way. And so people are trying looking + + align:start position:0% +of way. And so people are trying looking + + + align:start position:0% +of way. And so people are trying looking +at and thinking about how education + + align:start position:0% +at and thinking about how education + + + align:start position:0% +at and thinking about how education +technologies are adopted in Estonia and + + align:start position:0% +technologies are adopted in Estonia and + + + align:start position:0% +technologies are adopted in Estonia and +other kinds of ways. But it but it + + align:start position:0% +other kinds of ways. But it but it + + + align:start position:0% +other kinds of ways. But it but it +wasn't a policy that was just for the + + align:start position:0% +wasn't a policy that was just for the + + + align:start position:0% +wasn't a policy that was just for the +schools. They were like we're going to + + align:start position:0% +schools. They were like we're going to + + + align:start position:0% +schools. They were like we're going to +put Estonia on the map by having really + + align:start position:0% +put Estonia on the map by having really + + + align:start position:0% +put Estonia on the map by having really +good digital government services. And + + align:start position:0% +good digital government services. And + + + align:start position:0% +good digital government services. And +that national policy decision ends up + + align:start position:0% +that national policy decision ends up + + + align:start position:0% +that national policy decision ends up +affecting the learning experiences of + + align:start position:0% +affecting the learning experiences of + + + align:start position:0% +affecting the learning experiences of +kids in schools in all kinds of places. + + align:start position:0% +kids in schools in all kinds of places. + + + align:start position:0% +kids in schools in all kinds of places. +Yeah, that's a great example. + + align:start position:0% +Yeah, that's a great example. + + + align:start position:0% +Yeah, that's a great example. +um students what are what are what are + + align:start position:0% +um students what are what are what are + + + align:start position:0% +um students what are what are what are +the interests and and and disincentives + + align:start position:0% +the interests and and and disincentives + + + align:start position:0% +the interests and and and disincentives +of students. + + align:start position:0% + + + + align:start position:0% + +It's cool. It's a new piece of + + align:start position:0% +It's cool. It's a new piece of + + + align:start position:0% +It's cool. It's a new piece of +technology. Okay. So, almost all of us + + align:start position:0% +technology. Okay. So, almost all of us + + + align:start position:0% +technology. Okay. So, almost all of us +like novelty. Um that is one of the + + align:start position:0% +like novelty. Um that is one of the + + + align:start position:0% +like novelty. Um that is one of the +advantages that technology has. One of + + align:start position:0% +advantages that technology has. One of + + + align:start position:0% +advantages that technology has. One of +the um uh although an amazing thing + + align:start position:0% +the um uh although an amazing thing + + + align:start position:0% +the um uh although an amazing thing +about novelty is how shockingly quickly + + align:start position:0% +about novelty is how shockingly quickly + + + align:start position:0% +about novelty is how shockingly quickly +it wears off. Um actually I was reading + + align:start position:0% +it wears off. Um actually I was reading + + + align:start position:0% +it wears off. Um actually I was reading +this on Reddit the other day. someone a + + align:start position:0% +this on Reddit the other day. someone a + + + align:start position:0% +this on Reddit the other day. someone a +teacher was being like like I don't like + + align:start position:0% +teacher was being like like I don't like + + + align:start position:0% +teacher was being like like I don't like +I brought a Nintendo Switch into class + + align:start position:0% +I brought a Nintendo Switch into class + + + align:start position:0% +I brought a Nintendo Switch into class +so we could play these mathematical + + align:start position:0% +so we could play these mathematical + + + align:start position:0% +so we could play these mathematical +logic games and my students were like oh + + align:start position:0% +logic games and my students were like oh + + + align:start position:0% +logic games and my students were like oh +please miss can we just do worksheets + + align:start position:0% +please miss can we just do worksheets + + + align:start position:0% +please miss can we just do worksheets +and I was like fine do worksheets then + + align:start position:0% +and I was like fine do worksheets then + + + align:start position:0% +and I was like fine do worksheets then +um but you know they're like oh man you + + align:start position:0% +um but you know they're like oh man you + + + align:start position:0% +um but you know they're like oh man you +want you play some online game I don't + + align:start position:0% +want you play some online game I don't + + + align:start position:0% +want you play some online game I don't +want to play you know now there would + + align:start position:0% +want to play you know now there would + + + align:start position:0% +want to play you know now there would +have been some moment that this class + + align:start position:0% +have been some moment that this class + + + align:start position:0% +have been some moment that this class +would be like what we could play a + + align:start position:0% +would be like what we could play a + + + align:start position:0% +would be like what we could play a +computer game in class this is amazing + + align:start position:0% +computer game in class this is amazing + + + align:start position:0% +computer game in class this is amazing +um but that is you know um it's a sort + + align:start position:0% +um but that is you know um it's a sort + + + align:start position:0% +um but that is you know um it's a sort +of it's a it's an interesting feature of + + align:start position:0% +of it's a it's an interesting feature of + + + align:start position:0% +of it's a it's an interesting feature of +education technology adoption that like + + align:start position:0% +education technology adoption that like + + + align:start position:0% +education technology adoption that like +novelty can be extremely compelling for + + align:start position:0% +novelty can be extremely compelling for + + + align:start position:0% +novelty can be extremely compelling for +a short period of time and then wear off + + align:start position:0% +a short period of time and then wear off + + + align:start position:0% +a short period of time and then wear off +pretty quickly. Do you have any comment + + align:start position:0% +pretty quickly. Do you have any comment + + + align:start position:0% +pretty quickly. Do you have any comment +on like why students default is now back + + align:start position:0% +on like why students default is now back + + + align:start position:0% +on like why students default is now back +to that pen and paper like the way like + + align:start position:0% +to that pen and paper like the way like + + + align:start position:0% +to that pen and paper like the way like +because I mean people are always like + + align:start position:0% +because I mean people are always like + + + align:start position:0% +because I mean people are always like +education has been the same for decades + + align:start position:0% +education has been the same for decades + + + align:start position:0% +education has been the same for decades +and why does it always look this way + + align:start position:0% +and why does it always look this way + + + align:start position:0% +and why does it always look this way +even after we've reformed it like why is + + align:start position:0% +even after we've reformed it like why is + + + align:start position:0% +even after we've reformed it like why is +the default that pen and paper? Good. So + + align:start position:0% +the default that pen and paper? Good. So + + + align:start position:0% +the default that pen and paper? Good. So +what well let's just highlight an + + align:start position:0% +what well let's just highlight an + + + align:start position:0% +what well let's just highlight an +important thing that you observed um + + align:start position:0% +important thing that you observed um + + + align:start position:0% +important thing that you observed um +which we we were talking about over here + + align:start position:0% +which we we were talking about over here + + + align:start position:0% +which we we were talking about over here +too which is just schools are incredibly + + align:start position:0% +too which is just schools are incredibly + + + align:start position:0% +too which is just schools are incredibly +conservative institutions. Um why why + + align:start position:0% +conservative institutions. Um why why + + + align:start position:0% +conservative institutions. Um why why +why would that cons small C conser not + + align:start position:0% +why would that cons small C conser not + + + align:start position:0% +why would that cons small C conser not +rightwing some of them are but um small + + align:start position:0% +rightwing some of them are but um small + + + align:start position:0% +rightwing some of them are but um small +C conservative they do things the same + + align:start position:0% +C conservative they do things the same + + + align:start position:0% +C conservative they do things the same +way over and over again. Um what are + + align:start position:0% +way over and over again. Um what are + + + align:start position:0% +way over and over again. Um what are +some possible reasons for that? One is + + align:start position:0% +some possible reasons for that? One is + + + align:start position:0% +some possible reasons for that? One is +if you went and interviewed parents and + + align:start position:0% +if you went and interviewed parents and + + + align:start position:0% +if you went and interviewed parents and +said who are another stakeholder that a + + align:start position:0% +said who are another stakeholder that a + + + align:start position:0% +said who are another stakeholder that a +bunch of people brought up um how much + + align:start position:0% +bunch of people brought up um how much + + + align:start position:0% +bunch of people brought up um how much +do you want us experimenting with your + + align:start position:0% +do you want us experimenting with your + + + align:start position:0% +do you want us experimenting with your +children? Um the answer to that is going + + align:start position:0% +children? Um the answer to that is going + + + align:start position:0% +children? Um the answer to that is going +to be pretty low. Like the enthusiasm + + align:start position:0% +to be pretty low. Like the enthusiasm + + + align:start position:0% +to be pretty low. Like the enthusiasm +that people have for experimenting on + + align:start position:0% +that people have for experimenting on + + + align:start position:0% +that people have for experimenting on +children is low. Um second um everyone + + align:start position:0% +children is low. Um second um everyone + + + align:start position:0% +children is low. Um second um everyone +in the educational system who's an adult + + align:start position:0% +in the educational system who's an adult + + + align:start position:0% +in the educational system who's an adult +has what's been sometimes called the + + align:start position:0% +has what's been sometimes called the + + + align:start position:0% +has what's been sometimes called the +apprenticeship of observation. Um you + + align:start position:0% +apprenticeship of observation. Um you + + + align:start position:0% +apprenticeship of observation. Um you +all have been in school somewhere + + align:start position:0% +all have been in school somewhere + + + align:start position:0% +all have been in school somewhere +between like 13 and 18 years. Um and + + align:start position:0% +between like 13 and 18 years. Um and + + + align:start position:0% +between like 13 and 18 years. Um and +that shapes your experience. And so + + align:start position:0% +that shapes your experience. And so + + + align:start position:0% +that shapes your experience. And so +people who have roughly the same + + align:start position:0% +people who have roughly the same + + + align:start position:0% +people who have roughly the same +education level as you go into schools + + align:start position:0% +education level as you go into schools + + + align:start position:0% +education level as you go into schools +and become teachers and they bring that + + align:start position:0% +and become teachers and they bring that + + + align:start position:0% +and become teachers and they bring that +13, 18, 20 years of educational + + align:start position:0% +13, 18, 20 years of educational + + + align:start position:0% +13, 18, 20 years of educational +experience with them. Um, and that + + align:start position:0% +experience with them. Um, and that + + + align:start position:0% +experience with them. Um, and that +shapes the way you think schools should + + align:start position:0% +shapes the way you think schools should + + + align:start position:0% +shapes the way you think schools should +unfold. Um, parents can bring those + + align:start position:0% +unfold. Um, parents can bring those + + + align:start position:0% +unfold. Um, parents can bring those +expectations in. I was I will never + + align:start position:0% +expectations in. I was I will never + + + align:start position:0% +expectations in. I was I will never +forget this. I was once working I was + + align:start position:0% +forget this. I was once working I was + + + align:start position:0% +forget this. I was once working I was +conversing with a school in Utah that + + align:start position:0% +conversing with a school in Utah that + + + align:start position:0% +conversing with a school in Utah that +was trying to switch to openly licensed + + align:start position:0% +was trying to switch to openly licensed + + + align:start position:0% +was trying to switch to openly licensed +materials. It was pretty I don't know 15 + + align:start position:0% +materials. It was pretty I don't know 15 + + + align:start position:0% +materials. It was pretty I don't know 15 +years ago, 18 years ago or something + + align:start position:0% +years ago, 18 years ago or something + + + align:start position:0% +years ago, 18 years ago or something +like that. They were trying to get away + + align:start position:0% +like that. They were trying to get away + + + align:start position:0% +like that. They were trying to get away +from textbooks and to have people use + + align:start position:0% +from textbooks and to have people use + + + align:start position:0% +from textbooks and to have people use +digital materials, particularly digital + + align:start position:0% +digital materials, particularly digital + + + align:start position:0% +digital materials, particularly digital +materials that their teachers could edit + + align:start position:0% +materials that their teachers could edit + + + align:start position:0% +materials that their teachers could edit +um so that they could make them, you + + align:start position:0% +um so that they could make them, you + + + align:start position:0% +um so that they could make them, you +know, tailor to their students and + + align:start position:0% +know, tailor to their students and + + + align:start position:0% +know, tailor to their students and +things like that. And they said and they + + align:start position:0% +things like that. And they said and they + + + align:start position:0% +things like that. And they said and they +said, "But they still kept textbooks in + + align:start position:0% +said, "But they still kept textbooks in + + + align:start position:0% +said, "But they still kept textbooks in +classroom." And you know, I can't tell + + align:start position:0% +classroom." And you know, I can't tell + + + align:start position:0% +classroom." And you know, I can't tell +you whether or not that's true, but he + + align:start position:0% +you whether or not that's true, but he + + + align:start position:0% +you whether or not that's true, but he +says, "The reason why we keep textbooks + + align:start position:0% +says, "The reason why we keep textbooks + + + align:start position:0% +says, "The reason why we keep textbooks +in classrooms is if there aren't + + align:start position:0% +in classrooms is if there aren't + + + align:start position:0% +in classrooms is if there aren't +textbooks in classrooms, parents will be + + align:start position:0% +textbooks in classrooms, parents will be + + + align:start position:0% +textbooks in classrooms, parents will be +upset." Um that like parent like parents + + align:start position:0% +upset." Um that like parent like parents + + + align:start position:0% +upset." Um that like parent like parents +when they go into a classroom expect to + + align:start position:0% +when they go into a classroom expect to + + + align:start position:0% +when they go into a classroom expect to +see textbooks there. Basically, it was + + align:start position:0% +see textbooks there. Basically, it was + + + align:start position:0% +see textbooks there. Basically, it was +cheaper to keep buying enough textbooks + + align:start position:0% +cheaper to keep buying enough textbooks + + + align:start position:0% +cheaper to keep buying enough textbooks +to be in all of the classrooms than it + + align:start position:0% +to be in all of the classrooms than it + + + align:start position:0% +to be in all of the classrooms than it +was to like hire administrators to + + align:start position:0% +was to like hire administrators to + + + align:start position:0% +was to like hire administrators to +explain to parents why there weren't + + align:start position:0% +explain to parents why there weren't + + + align:start position:0% +explain to parents why there weren't +textbooks in the classroom anymore. Um + + align:start position:0% +textbooks in the classroom anymore. Um + + + align:start position:0% +textbooks in the classroom anymore. Um +so all of these different stakeholders + + align:start position:0% +so all of these different stakeholders + + + align:start position:0% +so all of these different stakeholders +um this sort of conservative vision of + + align:start position:0% +um this sort of conservative vision of + + + align:start position:0% +um this sort of conservative vision of +education is kind of part of that. Um + + align:start position:0% +education is kind of part of that. Um + + + align:start position:0% +education is kind of part of that. Um +one possibility is that that's really + + align:start position:0% +one possibility is that that's really + + + align:start position:0% +one possibility is that that's really +bad. Um that there actually like way + + align:start position:0% +bad. Um that there actually like way + + + align:start position:0% +bad. Um that there actually like way +better ways of doing things that are out + + align:start position:0% +better ways of doing things that are out + + + align:start position:0% +better ways of doing things that are out +there and it's a bummer that we're so + + align:start position:0% +there and it's a bummer that we're so + + + align:start position:0% +there and it's a bummer that we're so +conservative and that's really holding + + align:start position:0% +conservative and that's really holding + + + align:start position:0% +conservative and that's really holding +us back. Um, another possibility is that + + align:start position:0% +us back. Um, another possibility is that + + + align:start position:0% +us back. Um, another possibility is that +the practices that exist in schools have + + align:start position:0% +the practices that exist in schools have + + + align:start position:0% +the practices that exist in schools have +been refined over decades and centuries + + align:start position:0% +been refined over decades and centuries + + + align:start position:0% +been refined over decades and centuries +and they are the way they are because + + align:start position:0% +and they are the way they are because + + + align:start position:0% +and they are the way they are because +they're pretty darn good. Um, that they + + align:start position:0% +they're pretty darn good. Um, that they + + + align:start position:0% +they're pretty darn good. Um, that they +that that we keep doing certain kinds of + + align:start position:0% +that that we keep doing certain kinds of + + + align:start position:0% +that that we keep doing certain kinds of +things because they work. Um, so you'll + + align:start position:0% +things because they work. Um, so you'll + + + align:start position:0% +things because they work. Um, so you'll +have to figure out for yourself as you + + align:start position:0% +have to figure out for yourself as you + + + align:start position:0% +have to figure out for yourself as you +know if you hear examples of students + + align:start position:0% +know if you hear examples of students + + + align:start position:0% +know if you hear examples of students +kind of adopting old practices, are they + + align:start position:0% +kind of adopting old practices, are they + + + align:start position:0% +kind of adopting old practices, are they +adopting old practices because they work + + align:start position:0% +adopting old practices because they work + + + align:start position:0% +adopting old practices because they work +really well and because they like them, + + align:start position:0% +really well and because they like them, + + + align:start position:0% +really well and because they like them, +because they're comfortable and + + align:start position:0% +because they're comfortable and + + + align:start position:0% +because they're comfortable and +familiar? Um there's an argument that + + align:start position:0% +familiar? Um there's an argument that + + + align:start position:0% +familiar? Um there's an argument that +particularly in our age where students + + align:start position:0% +particularly in our age where students + + + align:start position:0% +particularly in our age where students +are sort of fixated on grades and + + align:start position:0% +are sort of fixated on grades and + + + align:start position:0% +are sort of fixated on grades and +performance in a way that they might + + align:start position:0% +performance in a way that they might + + + align:start position:0% +performance in a way that they might +have not been in decades past because + + align:start position:0% +have not been in decades past because + + + align:start position:0% +have not been in decades past because +you know not not because kids are like + + align:start position:0% +you know not not because kids are like + + + align:start position:0% +you know not not because kids are like +more materialistic or something. It's + + align:start position:0% +more materialistic or something. It's + + + align:start position:0% +more materialistic or something. It's +because of economic uncertainty. Um + + align:start position:0% +because of economic uncertainty. Um + + + align:start position:0% +because of economic uncertainty. Um +because as the gap between wealthy and + + align:start position:0% +because as the gap between wealthy and + + + align:start position:0% +because as the gap between wealthy and +poor people widens and the stakes of + + align:start position:0% +poor people widens and the stakes of + + + align:start position:0% +poor people widens and the stakes of +education become higher people become + + align:start position:0% +education become higher people become + + + align:start position:0% +education become higher people become +more fixated on it. Um and so those kids + + align:start position:0% +more fixated on it. Um and so those kids + + + align:start position:0% +more fixated on it. Um and so those kids +who are sort of adopting familiar + + align:start position:0% +who are sort of adopting familiar + + + align:start position:0% +who are sort of adopting familiar +matters like do they really like the + + align:start position:0% +matters like do they really like the + + + align:start position:0% +matters like do they really like the +familiarity or do they know how to do + + align:start position:0% +familiarity or do they know how to do + + + align:start position:0% +familiarity or do they know how to do +well in the familiarity and things like + + align:start position:0% +well in the familiarity and things like + + + align:start position:0% +well in the familiarity and things like +that. But again, like all the, you know, + + align:start position:0% +that. But again, like all the, you know, + + + align:start position:0% +that. But again, like all the, you know, +keep tying all the things we were + + align:start position:0% +keep tying all the things we were + + + align:start position:0% +keep tying all the things we were +talking about back to the decision of + + align:start position:0% +talking about back to the decision of + + + align:start position:0% +talking about back to the decision of +educators trying to implement new + + align:start position:0% +educators trying to implement new + + + align:start position:0% +educators trying to implement new +technologies. + + align:start position:0% +technologies. + + + align:start position:0% +technologies. +Um, everyone in your system is going to + + align:start position:0% +Um, everyone in your system is going to + + + align:start position:0% +Um, everyone in your system is going to +have some kind of conservative impulse + + align:start position:0% +have some kind of conservative impulse + + + align:start position:0% +have some kind of conservative impulse +all the way down to students. That + + align:start position:0% +all the way down to students. That + + + align:start position:0% +all the way down to students. That +conservative impulse might be balanced + + align:start position:0% +conservative impulse might be balanced + + + align:start position:0% +conservative impulse might be balanced +by the uh novelty effect that we're + + align:start position:0% +by the uh novelty effect that we're + + + align:start position:0% +by the uh novelty effect that we're +talking about, but it's in there. So if + + align:start position:0% +talking about, but it's in there. So if + + + align:start position:0% +talking about, but it's in there. So if +you want a new technology to really be + + align:start position:0% +you want a new technology to really be + + + align:start position:0% +you want a new technology to really be +adapted in some kind of meaningful way, + + align:start position:0% +adapted in some kind of meaningful way, + + + align:start position:0% +adapted in some kind of meaningful way, +one strategy you can have is to have it + + align:start position:0% +one strategy you can have is to have it + + + align:start position:0% +one strategy you can have is to have it +align with existing practices. You could + + align:start position:0% +align with existing practices. You could + + + align:start position:0% +align with existing practices. You could +say let's take technologies that do the + + align:start position:0% +say let's take technologies that do the + + + align:start position:0% +say let's take technologies that do the +kinds of things that are already + + align:start position:0% +kinds of things that are already + + + align:start position:0% +kinds of things that are already +happening in schools. Like that will be + + align:start position:0% +happening in schools. Like that will be + + + align:start position:0% +happening in schools. Like that will be +less upsetting. That'll require less + + align:start position:0% +less upsetting. That'll require less + + + align:start position:0% +less upsetting. That'll require less +training. That'll require less upset. It + + align:start position:0% +training. That'll require less upset. It + + + align:start position:0% +training. That'll require less upset. It +probably also won't help that much. Um I + + align:start position:0% +probably also won't help that much. Um I + + + align:start position:0% +probably also won't help that much. Um I +mean the people selling the technologies + + align:start position:0% +mean the people selling the technologies + + + align:start position:0% +mean the people selling the technologies +won't say that. But if you're just like + + align:start position:0% +won't say that. But if you're just like + + + align:start position:0% +won't say that. But if you're just like +digitizing existing practices, how how + + align:start position:0% +digitizing existing practices, how how + + + align:start position:0% +digitizing existing practices, how how +likely are you to have substantial gains + + align:start position:0% +likely are you to have substantial gains + + + align:start position:0% +likely are you to have substantial gains +from digitizing existing practices? Or + + align:start position:0% +from digitizing existing practices? Or + + + align:start position:0% +from digitizing existing practices? Or +maybe you're like a big ambitious + + align:start position:0% +maybe you're like a big ambitious + + + align:start position:0% +maybe you're like a big ambitious +reformer. You say, "No, no, no. We could + + align:start position:0% +reformer. You say, "No, no, no. We could + + + align:start position:0% +reformer. You say, "No, no, no. We could +be doing so much better. We could go + + align:start position:0% +be doing so much better. We could go + + + align:start position:0% +be doing so much better. We could go +from 2% to 100% efficiency in schools. + + align:start position:0% +from 2% to 100% efficiency in schools. + + + align:start position:0% +from 2% to 100% efficiency in schools. +We just have to make big changes in our + + align:start position:0% +We just have to make big changes in our + + + align:start position:0% +We just have to make big changes in our +practice." Well, making big changes in + + align:start position:0% +practice." Well, making big changes in + + + align:start position:0% +practice." Well, making big changes in +practice requires convincing people to + + align:start position:0% +practice requires convincing people to + + + align:start position:0% +practice requires convincing people to +change all of these things. Um there was + + align:start position:0% +change all of these things. Um there was + + + align:start position:0% +change all of these things. Um there was +a I you know, I've read this book a + + align:start position:0% +a I you know, I've read this book a + + + align:start position:0% +a I you know, I've read this book a +zillion times now, but I was just + + align:start position:0% +zillion times now, but I was just + + + align:start position:0% +zillion times now, but I was just +revisiting um a line in here that I + + align:start position:0% +revisiting um a line in here that I + + + align:start position:0% +revisiting um a line in here that I +loved. Um it was uh he says something + + align:start position:0% +loved. Um it was uh he says something + + + align:start position:0% +loved. Um it was uh he says something +towards the end that were like + + align:start position:0% +towards the end that were like + + + align:start position:0% +towards the end that were like +um settings have plans for their + + align:start position:0% +um settings have plans for their + + + align:start position:0% +um settings have plans for their +inhabitants. Anybody remember that? He + + align:start position:0% +inhabitants. Anybody remember that? He + + + align:start position:0% +inhabitants. Anybody remember that? He +was he was talking about the physical + + align:start position:0% +was he was talking about the physical + + + align:start position:0% +was he was talking about the physical +layout of a classroom but but he was + + align:start position:0% +layout of a classroom but but he was + + + align:start position:0% +layout of a classroom but but he was +using a broader sociological principle. + + align:start position:0% +using a broader sociological principle. + + + align:start position:0% +using a broader sociological principle. +Settings have plans for their + + align:start position:0% +Settings have plans for their + + + align:start position:0% +Settings have plans for their +inhabitants. Um people interact in a + + align:start position:0% +inhabitants. Um people interact in a + + + align:start position:0% +inhabitants. Um people interact in a +space in a certain way because the + + align:start position:0% +space in a certain way because the + + + align:start position:0% +space in a certain way because the +physical space is laid out and built in + + align:start position:0% +physical space is laid out and built in + + + align:start position:0% +physical space is laid out and built in +that way. So I was talking with these + + align:start position:0% +that way. So I was talking with these + + + align:start position:0% +that way. So I was talking with these +guys about one of the problems that film + + align:start position:0% +guys about one of the problems that film + + + align:start position:0% +guys about one of the problems that film +strips have. To have a film strip in + + align:start position:0% +strips have. To have a film strip in + + + align:start position:0% +strips have. To have a film strip in +your classroom, you have to take a giant + + align:start position:0% +your classroom, you have to take a giant + + + align:start position:0% +your classroom, you have to take a giant +projector on wheels and you have to roll + + align:start position:0% +projector on wheels and you have to roll + + + align:start position:0% +projector on wheels and you have to roll +it into the space. There would have been + + align:start position:0% +it into the space. There would have been + + + align:start position:0% +it into the space. There would have been +some classrooms, you know, filled with, + + align:start position:0% +some classrooms, you know, filled with, + + + align:start position:0% +some classrooms, you know, filled with, +you know, early 20th century, you know, + + align:start position:0% +you know, early 20th century, you know, + + + align:start position:0% +you know, early 20th century, you know, +urban schools with tons of immigrants + + align:start position:0% +urban schools with tons of immigrants + + + align:start position:0% +urban schools with tons of immigrants +who are pouring in on America's shores + + align:start position:0% +who are pouring in on America's shores + + + align:start position:0% +who are pouring in on America's shores +that don't have room in their classroom + + align:start position:0% +that don't have room in their classroom + + + align:start position:0% +that don't have room in their classroom +for a big thing. Um, the other thing + + align:start position:0% +for a big thing. Um, the other thing + + + align:start position:0% +for a big thing. Um, the other thing +that film strips had that was a huge + + align:start position:0% +that film strips had that was a huge + + + align:start position:0% +that film strips had that was a huge +pain is these giant film reels. You + + align:start position:0% +pain is these giant film reels. You + + + align:start position:0% +pain is these giant film reels. You +know, the early film reels were really, + + align:start position:0% +know, the early film reels were really, + + + align:start position:0% +know, the early film reels were really, +really big. Where are you going to put + + align:start position:0% +really big. Where are you going to put + + + align:start position:0% +really big. Where are you going to put +these things? You know, your town did + + align:start position:0% +these things? You know, your town did + + + align:start position:0% +these things? You know, your town did +not build a building um that that had + + align:start position:0% +not build a building um that that had + + + align:start position:0% +not build a building um that that had +like, you know, an archival film studio + + align:start position:0% +like, you know, an archival film studio + + + align:start position:0% +like, you know, an archival film studio +storage unit attached to it. Um let's + + align:start position:0% +storage unit attached to it. Um let's + + + align:start position:0% +storage unit attached to it. Um let's +say you have a big school and there are + + align:start position:0% +say you have a big school and there are + + + align:start position:0% +say you have a big school and there are +four first grade classes and you want to + + align:start position:0% +four first grade classes and you want to + + + align:start position:0% +four first grade classes and you want to +buy a film strip for all four of those + + align:start position:0% +buy a film strip for all four of those + + + align:start position:0% +buy a film strip for all four of those +first like are you going to build are + + align:start position:0% +first like are you going to build are + + + align:start position:0% +first like are you going to build are +you going to buy four copies of the same + + align:start position:0% +you going to buy four copies of the same + + + align:start position:0% +you going to buy four copies of the same +film strip? Like is each classroom going + + align:start position:0% +film strip? Like is each classroom going + + + align:start position:0% +film strip? Like is each classroom going +to have its own film library? If it has + + align:start position:0% +to have its own film library? If it has + + + align:start position:0% +to have its own film library? If it has +some centralized library, you have to + + align:start position:0% +some centralized library, you have to + + + align:start position:0% +some centralized library, you have to +have some way of like tagging, + + align:start position:0% +have some way of like tagging, + + + align:start position:0% +have some way of like tagging, +archiving, maintaining those things, + + align:start position:0% +archiving, maintaining those things, + + + align:start position:0% +archiving, maintaining those things, +bringing into classrooms. I mean, there + + align:start position:0% +bringing into classrooms. I mean, there + + + align:start position:0% +bringing into classrooms. I mean, there +are contemporary versions of all of + + align:start position:0% +are contemporary versions of all of + + + align:start position:0% +are contemporary versions of all of +these things. Um, oh, you want to give + + align:start position:0% +these things. Um, oh, you want to give + + + align:start position:0% +these things. Um, oh, you want to give +every kid a device? Um, how is that + + align:start position:0% +every kid a device? Um, how is that + + + align:start position:0% +every kid a device? Um, how is that +kid's device going to get on the + + align:start position:0% +kid's device going to get on the + + + align:start position:0% +kid's device going to get on the +network? How is they going to be able to + + align:start position:0% +network? How is they going to be able to + + + align:start position:0% +network? How is they going to be able to +log in? Who's going to deal when they + + align:start position:0% +log in? Who's going to deal when they + + + align:start position:0% +log in? Who's going to deal when they +lose their password? What's going to + + align:start position:0% +lose their password? What's going to + + + align:start position:0% +lose their password? What's going to +happen when their devices break? Are you + + align:start position:0% +happen when their devices break? Are you + + + align:start position:0% +happen when their devices break? Are you +going to make a Are you going to make + + align:start position:0% +going to make a Are you going to make + + + align:start position:0% +going to make a Are you going to make +families pay for the devices they break? + + align:start position:0% +families pay for the devices they break? + + + align:start position:0% +families pay for the devices they break? +Your kids are super poor. They can't + + align:start position:0% +Your kids are super poor. They can't + + + align:start position:0% +Your kids are super poor. They can't +afford that. So, you're going to + + align:start position:0% +afford that. So, you're going to + + + align:start position:0% +afford that. So, you're going to +contract with insurance company. who on + + align:start position:0% +contract with insurance company. who on + + + align:start position:0% +contract with insurance company. who on +your staff has experience contracting + + align:start position:0% +your staff has experience contracting + + + align:start position:0% +your staff has experience contracting +with insurance companies to ensure um uh + + align:start position:0% +with insurance companies to ensure um uh + + + align:start position:0% +with insurance companies to ensure um uh +you know uh uh computing devices like + + align:start position:0% +you know uh uh computing devices like + + + align:start position:0% +you know uh uh computing devices like +you didn't learn that at your I mean + + align:start position:0% +you didn't learn that at your I mean + + + align:start position:0% +you didn't learn that at your I mean +we'll talk with the education school + + align:start position:0% +we'll talk with the education school + + + align:start position:0% +we'll talk with the education school +deans on Wednesday but I'm pretty sure + + align:start position:0% +deans on Wednesday but I'm pretty sure + + + align:start position:0% +deans on Wednesday but I'm pretty sure +they're not teaching their um their + + align:start position:0% +they're not teaching their um their + + + align:start position:0% +they're not teaching their um their +their their students how to manage + + align:start position:0% +their their students how to manage + + + align:start position:0% +their their students how to manage +insurance contracts and things like + + align:start position:0% +insurance contracts and things like + + + align:start position:0% +insurance contracts and things like +that. Um all of those things become you + + align:start position:0% +that. Um all of those things become you + + + align:start position:0% +that. Um all of those things become you +know um if if well they you know they + + align:start position:0% +know um if if well they you know they + + + align:start position:0% +know um if if well they you know they +have a combination of incentives and + + align:start position:0% +have a combination of incentives and + + + align:start position:0% +have a combination of incentives and +disincentives that are associated with + + align:start position:0% +disincentives that are associated with + + + align:start position:0% +disincentives that are associated with +them. Um, good. Any any of these other + + align:start position:0% +them. Um, good. Any any of these other + + + align:start position:0% +them. Um, good. Any any of these other +people that it seems like is important + + align:start position:0% +people that it seems like is important + + + align:start position:0% +people that it seems like is important +for us to touch on before we um come to + + align:start position:0% +for us to touch on before we um come to + + + align:start position:0% +for us to touch on before we um come to +conclusion. We talked about parents. Um, + + align:start position:0% +conclusion. We talked about parents. Um, + + + align:start position:0% +conclusion. We talked about parents. Um, +you know, I I mean I don't know that how + + align:start position:0% +you know, I I mean I don't know that how + + + align:start position:0% +you know, I I mean I don't know that how +much we talked maybe here's one last + + align:start position:0% +much we talked maybe here's one last + + + align:start position:0% +much we talked maybe here's one last +thing that we could sort of talk about. + + align:start position:0% +thing that we could sort of talk about. + + + align:start position:0% +thing that we could sort of talk about. +We talked a little bit about school + + align:start position:0% +We talked a little bit about school + + + align:start position:0% +We talked a little bit about school +administrators. Um, but like a a thing + + align:start position:0% +administrators. Um, but like a a thing + + + align:start position:0% +administrators. Um, but like a a thing +to be particularly attentive to um in uh + + align:start position:0% +to be particularly attentive to um in uh + + + align:start position:0% +to be particularly attentive to um in uh +um in schools is just how many different + + align:start position:0% +um in schools is just how many different + + + align:start position:0% +um in schools is just how many different +kinds of adults with different roles + + align:start position:0% +kinds of adults with different roles + + + align:start position:0% +kinds of adults with different roles +there are. So, we talked about teachers. + + align:start position:0% +there are. So, we talked about teachers. + + + align:start position:0% +there are. So, we talked about teachers. +Um, there are people who are school + + align:start position:0% +Um, there are people who are school + + + align:start position:0% +Um, there are people who are school +principles. Like, if you're a school + + align:start position:0% +principles. Like, if you're a school + + + align:start position:0% +principles. Like, if you're a school +principal, what are what are the most + + align:start position:0% +principal, what are what are the most + + + align:start position:0% +principal, what are what are the most +urgent concerns that you have on any + + align:start position:0% +urgent concerns that you have on any + + + align:start position:0% +urgent concerns that you have on any +given day? Um, what what like what are + + align:start position:0% +given day? Um, what what like what are + + + align:start position:0% +given day? Um, what what like what are +what are the main incentives you have as + + align:start position:0% +what are the main incentives you have as + + + align:start position:0% +what are the main incentives you have as +a school principal? Your budget. Yep. + + align:start position:0% +a school principal? Your budget. Yep. + + + align:start position:0% +a school principal? Your budget. Yep. +You got to make sure you can pay for + + align:start position:0% +You got to make sure you can pay for + + + align:start position:0% +You got to make sure you can pay for +everything. A teacher's not worried + + align:start position:0% +everything. A teacher's not worried + + + align:start position:0% +everything. A teacher's not worried +about that. Teacher will buy as much, + + align:start position:0% +about that. Teacher will buy as much, + + + align:start position:0% +about that. Teacher will buy as much, +you know, if a school pay for it, + + align:start position:0% +you know, if a school pay for it, + + + align:start position:0% +you know, if a school pay for it, +they'll take as much technology as they + + align:start position:0% +they'll take as much technology as they + + + align:start position:0% +they'll take as much technology as they +want. you know, some of them, but + + align:start position:0% +want. you know, some of them, but + + + align:start position:0% +want. you know, some of them, but +principles have to balance a budget or + + align:start position:0% +principles have to balance a budget or + + + align:start position:0% +principles have to balance a budget or +or, you know, I mean, the weird thing is + + align:start position:0% +or, you know, I mean, the weird thing is + + + align:start position:0% +or, you know, I mean, the weird thing is +in the United States, it may not at all + + align:start position:0% +in the United States, it may not at all + + + align:start position:0% +in the United States, it may not at all +be a principal's role to balance a + + align:start position:0% +be a principal's role to balance a + + + align:start position:0% +be a principal's role to balance a +budget. It may be entirely a district + + align:start position:0% +budget. It may be entirely a district + + + align:start position:0% +budget. It may be entirely a district +role. So, there are some school + + align:start position:0% +role. So, there are some school + + + align:start position:0% +role. So, there are some school +districts where the district will make + + align:start position:0% +districts where the district will make + + + align:start position:0% +districts where the district will make +all the purchasing decisions. There are + + align:start position:0% +all the purchasing decisions. There are + + + align:start position:0% +all the purchasing decisions. There are +other districts where the districts will + + align:start position:0% +other districts where the districts will + + + align:start position:0% +other districts where the districts will +take big chunks of money, send it down + + align:start position:0% +take big chunks of money, send it down + + + align:start position:0% +take big chunks of money, send it down +to schools, and say, "Schools, make all + + align:start position:0% +to schools, and say, "Schools, make all + + + align:start position:0% +to schools, and say, "Schools, make all +the purchasing decisions." + + align:start position:0% +the purchasing decisions." + + + align:start position:0% +the purchasing decisions." +Um, what what else is super important + + align:start position:0% +Um, what what else is super important + + + align:start position:0% +Um, what what else is super important +for principles? I was going to say like + + align:start position:0% +for principles? I was going to say like + + + align:start position:0% +for principles? I was going to say like +just like maintaining the school + + align:start position:0% +just like maintaining the school + + + align:start position:0% +just like maintaining the school +building itself for like student safety. + + align:start position:0% +building itself for like student safety. + + + align:start position:0% +building itself for like student safety. +Yeah. Yep. student safety, maintaining + + align:start position:0% +Yeah. Yep. student safety, maintaining + + + align:start position:0% +Yeah. Yep. student safety, maintaining +the physical school building, making, + + align:start position:0% +the physical school building, making, + + + align:start position:0% +the physical school building, making, +you know, making sure things are running + + align:start position:0% +you know, making sure things are running + + + align:start position:0% +you know, making sure things are running +and operating and stuff like that. Are + + align:start position:0% +and operating and stuff like that. Are + + + align:start position:0% +and operating and stuff like that. Are +they also managing the relationships + + align:start position:0% +they also managing the relationships + + + align:start position:0% +they also managing the relationships +with like the district and also parents + + align:start position:0% +with like the district and also parents + + + align:start position:0% +with like the district and also parents +like all these outside? Yep. Yep. So, + + align:start position:0% +like all these outside? Yep. Yep. So, + + + align:start position:0% +like all these outside? Yep. Yep. So, +so, so, um, they and they are, you know, + + align:start position:0% +so, so, um, they and they are, you know, + + + align:start position:0% +so, so, um, they and they are, you know, +principles are sort of quintessential + + align:start position:0% +principles are sort of quintessential + + + align:start position:0% +principles are sort of quintessential +organizational behavior, middle + + align:start position:0% +organizational behavior, middle + + + align:start position:0% +organizational behavior, middle +managers. Um, they're like empowered to + + align:start position:0% +managers. Um, they're like empowered to + + + align:start position:0% +managers. Um, they're like empowered to +do some things but not others. They're + + align:start position:0% +do some things but not others. They're + + + align:start position:0% +do some things but not others. They're +accountable to lots of different kinds + + align:start position:0% +accountable to lots of different kinds + + + align:start position:0% +accountable to lots of different kinds +of stakeholders. There's all kind of + + align:start position:0% +of stakeholders. There's all kind of + + + align:start position:0% +of stakeholders. There's all kind of +complexity in what they're doing. Um uh + + align:start position:0% +complexity in what they're doing. Um uh + + + align:start position:0% +complexity in what they're doing. Um uh +a lot of them are pretty keyed evaluated + + align:start position:0% +a lot of them are pretty keyed evaluated + + + align:start position:0% +a lot of them are pretty keyed evaluated +based on test scores like especially in + + align:start position:0% +based on test scores like especially in + + + align:start position:0% +based on test scores like especially in +places where people are at where + + align:start position:0% +places where people are at where + + + align:start position:0% +places where people are at where +students are at risk of not passing + + align:start position:0% +students are at risk of not passing + + + align:start position:0% +students are at risk of not passing +tests. Um and depending upon the policy + + align:start position:0% +tests. Um and depending upon the policy + + + align:start position:0% +tests. Um and depending upon the policy +infrastructure test scores really matter + + align:start position:0% +infrastructure test scores really matter + + + align:start position:0% +infrastructure test scores really matter +to them. Um safety and the orderly + + align:start position:0% +to them. Um safety and the orderly + + + align:start position:0% +to them. Um safety and the orderly +operation of schools man like you know + + align:start position:0% +operation of schools man like you know + + + align:start position:0% +operation of schools man like you know +in in like every person in a building + + align:start position:0% +in in like every person in a building + + + align:start position:0% +in in like every person in a building +wants schools to be orderly but when + + align:start position:0% +wants schools to be orderly but when + + + align:start position:0% +wants schools to be orderly but when +schools are disorderly the person who + + align:start position:0% +schools are disorderly the person who + + + align:start position:0% +schools are disorderly the person who +has to deal with it the most is like an + + align:start position:0% +has to deal with it the most is like an + + + align:start position:0% +has to deal with it the most is like an +assistant principal or the principal. + + align:start position:0% +assistant principal or the principal. + + + align:start position:0% +assistant principal or the principal. +It's just more work for them. um you + + align:start position:0% +It's just more work for them. um you + + + align:start position:0% +It's just more work for them. um you +know you know um you like let all the + + align:start position:0% +know you know um you like let all the + + + align:start position:0% +know you know um you like let all the +kids have phones and you know fights + + align:start position:0% +kids have phones and you know fights + + + align:start position:0% +kids have phones and you know fights +break out and all kinds of things happen + + align:start position:0% +break out and all kinds of things happen + + + align:start position:0% +break out and all kinds of things happen +like it's the you know teachers have to + + align:start position:0% +like it's the you know teachers have to + + + align:start position:0% +like it's the you know teachers have to +deal with it but the principles really + + align:start position:0% +deal with it but the principles really + + + align:start position:0% +deal with it but the principles really +have to deal with it. I just like really + + align:start position:0% +have to deal with it. I just like really + + + align:start position:0% +have to deal with it. I just like really +short comment just when you asked us + + align:start position:0% +short comment just when you asked us + + + align:start position:0% +short comment just when you asked us +like what does a principal do? I've been + + align:start position:0% +like what does a principal do? I've been + + + align:start position:0% +like what does a principal do? I've been +around them my entire life and I was + + align:start position:0% +around them my entire life and I was + + + align:start position:0% +around them my entire life and I was +like I can only think of like two or + + align:start position:0% +like I can only think of like two or + + + align:start position:0% +like I can only think of like two or +three things that I know a principal + + align:start position:0% +three things that I know a principal + + + align:start position:0% +three things that I know a principal +actually does and I just think it's + + align:start position:0% +actually does and I just think it's + + + align:start position:0% +actually does and I just think it's +really strange that like most people + + align:start position:0% +really strange that like most people + + + align:start position:0% +really strange that like most people +aren't sitting you down being like this + + align:start position:0% +aren't sitting you down being like this + + + align:start position:0% +aren't sitting you down being like this +is the person you go to for x y and z + + align:start position:0% +is the person you go to for x y and z + + + align:start position:0% +is the person you go to for x y and z +things + + align:start position:0% +things + + + align:start position:0% +things +around these organizations good good so + + align:start position:0% +around these organizations good good so + + + align:start position:0% +around these organizations good good so +there there are I think there are a few + + align:start position:0% +there there are I think there are a few + + + align:start position:0% +there there are I think there are a few +things that you can grasp from that + + align:start position:0% +things that you can grasp from that + + + align:start position:0% +things that you can grasp from that +insight is first of all schools are just + + align:start position:0% +insight is first of all schools are just + + + align:start position:0% +insight is first of all schools are just +unbelievably complicated um I've spent + + align:start position:0% +unbelievably complicated um I've spent + + + align:start position:0% +unbelievably complicated um I've spent +the last 20 years basically doing + + align:start position:0% +the last 20 years basically doing + + + align:start position:0% +the last 20 years basically doing +nothing but thinking about schools and I + + align:start position:0% +nothing but thinking about schools and I + + + align:start position:0% +nothing but thinking about schools and I +still don't understand all the things + + align:start position:0% +still don't understand all the things + + + align:start position:0% +still don't understand all the things +that are going on in there. They are + + align:start position:0% +that are going on in there. They are + + + align:start position:0% +that are going on in there. They are +like if you want like just as an + + align:start position:0% +like if you want like just as an + + + align:start position:0% +like if you want like just as an +ecosystem, they're unbelievably complex + + align:start position:0% +ecosystem, they're unbelievably complex + + + align:start position:0% +ecosystem, they're unbelievably complex +and fascinating. Um the second is as you + + align:start position:0% +and fascinating. Um the second is as you + + + align:start position:0% +and fascinating. Um the second is as you +transition if you decide to work be + + align:start position:0% +transition if you decide to work be + + + align:start position:0% +transition if you decide to work be +involved in education, you sort you kind + + align:start position:0% +involved in education, you sort you kind + + + align:start position:0% +involved in education, you sort you kind +of have to like relearn all this stuff + + align:start position:0% +of have to like relearn all this stuff + + + align:start position:0% +of have to like relearn all this stuff +going from a student to being someone + + align:start position:0% +going from a student to being someone + + + align:start position:0% +going from a student to being someone +who's working in education. Like there's + + align:start position:0% +who's working in education. Like there's + + + align:start position:0% +who's working in education. Like there's +all kinds of things that were hidden + + align:start position:0% +all kinds of things that were hidden + + + align:start position:0% +all kinds of things that were hidden +from you, masked from you, or just sort + + align:start position:0% +from you, masked from you, or just sort + + + align:start position:0% +from you, masked from you, or just sort +of weren't important to you. You know, + + align:start position:0% +of weren't important to you. You know, + + + align:start position:0% +of weren't important to you. You know, +like the odds that any of you were like + + align:start position:0% +like the odds that any of you were like + + + align:start position:0% +like the odds that any of you were like +real troublemakers is pretty low given + + align:start position:0% +real troublemakers is pretty low given + + + align:start position:0% +real troublemakers is pretty low given +that you're at MIT. Um but you know + + align:start position:0% +that you're at MIT. Um but you know + + + align:start position:0% +that you're at MIT. Um but you know +there you know there's a classroom full + + align:start position:0% +there you know there's a classroom full + + + align:start position:0% +there you know there's a classroom full +of people sitting somewhere um that like + + align:start position:0% +of people sitting somewhere um that like + + + align:start position:0% +of people sitting somewhere um that like +knew principles pretty intimately + + align:start position:0% +knew principles pretty intimately + + + align:start position:0% +knew principles pretty intimately +because they spent a bunch of time in + + align:start position:0% +because they spent a bunch of time in + + + align:start position:0% +because they spent a bunch of time in +their office um because you know because + + align:start position:0% +their office um because you know because + + + align:start position:0% +their office um because you know because +of things that they did and so forth. So + + align:start position:0% +of things that they did and so forth. So + + + align:start position:0% +of things that they did and so forth. So +good. Yeah. If if if part of what + + align:start position:0% +good. Yeah. If if if part of what + + + align:start position:0% +good. Yeah. If if if part of what +happens to you in this class is uh a lot + + align:start position:0% +happens to you in this class is uh a lot + + + align:start position:0% +happens to you in this class is uh a lot +of times in social science we talk about + + align:start position:0% +of times in social science we talk about + + + align:start position:0% +of times in social science we talk about +making the familiar unfamiliar. Um a + + align:start position:0% +making the familiar unfamiliar. Um a + + + align:start position:0% +making the familiar unfamiliar. Um a +thing that you've looked at your whole + + align:start position:0% +thing that you've looked at your whole + + + align:start position:0% +thing that you've looked at your whole +life and being like whoa look at all + + align:start position:0% +life and being like whoa look at all + + + align:start position:0% +life and being like whoa look at all +these things there that I wasn't sort of + + align:start position:0% +these things there that I wasn't sort of + + + align:start position:0% +these things there that I wasn't sort of +paying attention to or you know wasn't + + align:start position:0% +paying attention to or you know wasn't + + + align:start position:0% +paying attention to or you know wasn't +made aware to me and those kinds of + + align:start position:0% +made aware to me and those kinds of + + + align:start position:0% +made aware to me and those kinds of +things. Um maybe here's here's one very + + align:start position:0% +things. Um maybe here's here's one very + + + align:start position:0% +things. Um maybe here's here's one very +concrete thing. Um uh let's think of + + align:start position:0% +concrete thing. Um uh let's think of + + + align:start position:0% +concrete thing. Um uh let's think of +something like uh um a student + + align:start position:0% +something like uh um a student + + + align:start position:0% +something like uh um a student +information system. Um or Canvas. Let's + + align:start position:0% +information system. Um or Canvas. Let's + + + align:start position:0% +information system. Um or Canvas. Let's +think of something like a learning + + align:start position:0% +think of something like a learning + + + align:start position:0% +think of something like a learning +management system. Who spends the most + + align:start position:0% +management system. Who spends the most + + + align:start position:0% +management system. Who spends the most +time using + + align:start position:0% +time using + + + align:start position:0% +time using +Canvas? Tell me about the people who use + + align:start position:0% +Canvas? Tell me about the people who use + + + align:start position:0% +Canvas? Tell me about the people who use +Canvas. + + align:start position:0% +Canvas. + + + align:start position:0% +Canvas. +Students. Students spend a lot of hours + + align:start position:0% +Students. Students spend a lot of hours + + + align:start position:0% +Students. Students spend a lot of hours +logged in looking at stuff on Canvas. + + align:start position:0% +logged in looking at stuff on Canvas. + + + align:start position:0% +logged in looking at stuff on Canvas. +Who else looks at Canvas? Teachers. + + align:start position:0% +Who else looks at Canvas? Teachers. + + + align:start position:0% +Who else looks at Canvas? Teachers. +Teachers. Who buys Canvas? this true not + + align:start position:0% +Teachers. Who buys Canvas? this true not + + + align:start position:0% +Teachers. Who buys Canvas? this true not +students and teachers in in in uh um in + + align:start position:0% +students and teachers in in in uh um in + + + align:start position:0% +students and teachers in in in uh um in +business school I think they would call + + align:start position:0% +business school I think they would call + + + align:start position:0% +business school I think they would call +this a third party payer problem. Um so + + align:start position:0% +this a third party payer problem. Um so + + + align:start position:0% +this a third party payer problem. Um so +if you are a company that's making a + + align:start position:0% +if you are a company that's making a + + + align:start position:0% +if you are a company that's making a +learning management + + align:start position:0% +learning management + + + align:start position:0% +learning management +system who's like of your + + align:start position:0% +system who's like of your + + + align:start position:0% +system who's like of your +stakeholders who has the most power to + + align:start position:0% +stakeholders who has the most power to + + + align:start position:0% +stakeholders who has the most power to +determine whether or not your thing gets + + align:start position:0% +determine whether or not your thing gets + + + align:start position:0% +determine whether or not your thing gets +purchased like some director of + + align:start position:0% +purchased like some director of + + + align:start position:0% +purchased like some director of +education technology or something like + + align:start position:0% +education technology or something like + + + align:start position:0% +education technology or something like +that some IT person. So, if you ever if + + align:start position:0% +that some IT person. So, if you ever if + + + align:start position:0% +that some IT person. So, if you ever if +you've ever wondered like why is this so + + align:start position:0% +you've ever wondered like why is this so + + + align:start position:0% +you've ever wondered like why is this so +terrible? Um, it wasn't built for you. + + align:start position:0% +terrible? Um, it wasn't built for you. + + + align:start position:0% +terrible? Um, it wasn't built for you. +Like in some in some important ways, it + + align:start position:0% +Like in some in some important ways, it + + + align:start position:0% +Like in some in some important ways, it +was literally not built for you. It was + + align:start position:0% +was literally not built for you. It was + + + align:start position:0% +was literally not built for you. It was +built to solve the problems of some + + align:start position:0% +built to solve the problems of some + + + align:start position:0% +built to solve the problems of some +middle level information technology + + align:start position:0% +middle level information technology + + + align:start position:0% +middle level information technology +manager. Who's going to buy one of those + + align:start position:0% +manager. Who's going to buy one of those + + + align:start position:0% +manager. Who's going to buy one of those +things? Um, so third-party payer + + align:start position:0% +things? Um, so third-party payer + + + align:start position:0% +things? Um, so third-party payer +problems are rife across. I mean, the + + align:start position:0% +problems are rife across. I mean, the + + + align:start position:0% +problems are rife across. I mean, the +problem with third-party payer problems + + align:start position:0% +problem with third-party payer problems + + + align:start position:0% +problem with third-party payer problems +from like a classical economics point of + + align:start position:0% +from like a classical economics point of + + + align:start position:0% +from like a classical economics point of +view is you just have misaligned + + align:start position:0% +view is you just have misaligned + + + align:start position:0% +view is you just have misaligned +incentives. um you know um in in some + + align:start position:0% +incentives. um you know um in in some + + + align:start position:0% +incentives. um you know um in in some +respects you could say that improving + + align:start position:0% +respects you could say that improving + + + align:start position:0% +respects you could say that improving +the teaching and learning experience on + + align:start position:0% +the teaching and learning experience on + + + align:start position:0% +the teaching and learning experience on +canvas is a cost um it's something that + + align:start position:0% +canvas is a cost um it's something that + + + align:start position:0% +canvas is a cost um it's something that +like reduces your pro profit obviously + + align:start position:0% +like reduces your pro profit obviously + + + align:start position:0% +like reduces your pro profit obviously +you have to make it good enough so that + + align:start position:0% +you have to make it good enough so that + + + align:start position:0% +you have to make it good enough so that +you know if like enough teachers and + + align:start position:0% +you know if like enough teachers and + + + align:start position:0% +you know if like enough teachers and +stuff are rolled I once anyone ever have + + align:start position:0% +stuff are rolled I once anyone ever have + + + align:start position:0% +stuff are rolled I once anyone ever have +to use blackboard + + align:start position:0% +to use blackboard + + + align:start position:0% +to use blackboard +okay good um I once met the I once met + + align:start position:0% +okay good um I once met the I once met + + + align:start position:0% +okay good um I once met the I once met +the guy who made blackboard and I was + + align:start position:0% +the guy who made blackboard and I was + + + align:start position:0% +the guy who made blackboard and I was +just standing there in line behind him + + align:start position:0% +just standing there in line behind him + + + align:start position:0% +just standing there in line behind him +or something like that being like what + + align:start position:0% +or something like that being like what + + + align:start position:0% +or something like that being like what +would it be like to have made a piece of + + align:start position:0% +would it be like to have made a piece of + + + align:start position:0% +would it be like to have made a piece of +software that millions of people hate + + align:start position:0% +software that millions of people hate + + + align:start position:0% +software that millions of people hate +like what like what would it have been + + align:start position:0% +like what like what would it have been + + + align:start position:0% +like what like what would it have been +like to like introduce so much + + align:start position:0% +like to like introduce so much + + + align:start position:0% +like to like introduce so much +unhappiness in the world with what + + align:start position:0% +unhappiness in the world with what + + + align:start position:0% +unhappiness in the world with what +you've built like and I it was it would + + align:start position:0% +you've built like and I it was it would + + + align:start position:0% +you've built like and I it was it would +have been rude I think in the buffet + + align:start position:0% +have been rude I think in the buffet + + + align:start position:0% +have been rude I think in the buffet +line to to to ask him to ask him that + + align:start position:0% +line to to to ask him to ask him that + + + align:start position:0% +line to to to ask him to ask him that +question. Um here's another thing that I + + align:start position:0% +question. Um here's another thing that I + + + align:start position:0% +question. Um here's another thing that I +want to say about who buys these things + + align:start position:0% +want to say about who buys these things + + + align:start position:0% +want to say about who buys these things +and this is really um important too + + align:start position:0% +and this is really um important too + + + align:start position:0% +and this is really um important too +especially to any of you who are + + align:start position:0% +especially to any of you who are + + + align:start position:0% +especially to any of you who are +interested in either an education like + + align:start position:0% +interested in either an education like + + + align:start position:0% +interested in either an education like +starting an education startup or other + + align:start position:0% +starting an education startup or other + + + align:start position:0% +starting an education startup or other +kinds of things. Um uh who in a school + + align:start position:0% +kinds of things. Um uh who in a school + + + align:start position:0% +kinds of things. Um uh who in a school +can buy technology? What are some + + align:start position:0% +can buy technology? What are some + + + align:start position:0% +can buy technology? What are some +possible titles of people who buy + + align:start position:0% +possible titles of people who buy + + + align:start position:0% +possible titles of people who buy +technology? + + align:start position:0% + + + + align:start position:0% + +We've mentioned a few. Librarians, a + + align:start position:0% +We've mentioned a few. Librarians, a + + + align:start position:0% +We've mentioned a few. Librarians, a +librarian could buy technology. + + align:start position:0% +librarian could buy technology. + + + align:start position:0% +librarian could buy technology. +Department chair. A department chair + + align:start position:0% +Department chair. A department chair + + + align:start position:0% +Department chair. A department chair +could buy technology. + + align:start position:0% + + + + align:start position:0% + +Teacher. A teacher. They're amongst the + + align:start position:0% +Teacher. A teacher. They're amongst the + + + align:start position:0% +Teacher. A teacher. They're amongst the +least likely. Actually, one of the + + align:start position:0% +least likely. Actually, one of the + + + align:start position:0% +least likely. Actually, one of the +sometimes people have made the argument + + align:start position:0% +sometimes people have made the argument + + + align:start position:0% +sometimes people have made the argument +that a that a problem in the education + + align:start position:0% +that a that a problem in the education + + + align:start position:0% +that a that a problem in the education +system is it's very it's very difficult + + align:start position:0% +system is it's very it's very difficult + + + align:start position:0% +system is it's very it's very difficult +to have a real sort of bottomup + + align:start position:0% +to have a real sort of bottomup + + + align:start position:0% +to have a real sort of bottomup +marketplace kind of effect. Um like + + align:start position:0% +marketplace kind of effect. Um like + + + align:start position:0% +marketplace kind of effect. Um like +teachers have in most places teachers + + align:start position:0% +teachers have in most places teachers + + + align:start position:0% +teachers have in most places teachers +have very few discretionary dollars um + + align:start position:0% +have very few discretionary dollars um + + + align:start position:0% +have very few discretionary dollars um +to the I mean that's why they're like + + align:start position:0% +to the I mean that's why they're like + + + align:start position:0% +to the I mean that's why they're like +holding big sales and asking like you + + align:start position:0% +holding big sales and asking like you + + + align:start position:0% +holding big sales and asking like you +know when you become parents like your + + align:start position:0% +know when you become parents like your + + + align:start position:0% +know when you become parents like your +teachers will ask you to bring in boxes + + align:start position:0% +teachers will ask you to bring in boxes + + + align:start position:0% +teachers will ask you to bring in boxes +of tissues and things like that and + + align:start position:0% +of tissues and things like that and + + + align:start position:0% +of tissues and things like that and +you'll be like what what broken failed + + align:start position:0% +you'll be like what what broken failed + + + align:start position:0% +you'll be like what what broken failed +country do we live in where you cannot + + align:start position:0% +country do we live in where you cannot + + + align:start position:0% +country do we live in where you cannot +simply buy all the tissues that you need + + align:start position:0% +simply buy all the tissues that you need + + + align:start position:0% +simply buy all the tissues that you need +for the children um or paper two reams + + align:start position:0% +for the children um or paper two reams + + + align:start position:0% +for the children um or paper two reams +two yeah two yeah two reams of paper a + + align:start position:0% +two yeah two yeah two reams of paper a + + + align:start position:0% +two yeah two yeah two reams of paper a +semester for all your students you know + + align:start position:0% +semester for all your students you know + + + align:start position:0% +semester for all your students you know +all right so the teachers don't have in + + align:start position:0% +all right so the teachers don't have in + + + align:start position:0% +all right so the teachers don't have in +some cases they do, but in a lot of + + align:start position:0% +some cases they do, but in a lot of + + + align:start position:0% +some cases they do, but in a lot of +cases you don't know what I mean. + + align:start position:0% +cases you don't know what I mean. + + + align:start position:0% +cases you don't know what I mean. +Principles can buy things, directors of + + align:start position:0% +Principles can buy things, directors of + + + align:start position:0% +Principles can buy things, directors of +instructional technology can buy things, + + align:start position:0% +instructional technology can buy things, + + + align:start position:0% +instructional technology can buy things, +assistant superintendents can buy + + align:start position:0% +assistant superintendents can buy + + + align:start position:0% +assistant superintendents can buy +things, superintendents can buy things, + + align:start position:0% +things, superintendents can buy things, + + + align:start position:0% +things, superintendents can buy things, +school boards in some places can + + align:start position:0% +school boards in some places can + + + align:start position:0% +school boards in some places can +directly authorize kinds of things, + + align:start position:0% +directly authorize kinds of things, + + + align:start position:0% +directly authorize kinds of things, +although that's probably more rare, but + + align:start position:0% +although that's probably more rare, but + + + align:start position:0% +although that's probably more rare, but +they can push for it. Um, but the point + + align:start position:0% +they can push for it. Um, but the point + + + align:start position:0% +they can push for it. Um, but the point +is across the 13,000 school districts + + align:start position:0% +is across the 13,000 school districts + + + align:start position:0% +is across the 13,000 school districts +and 130,000 schools in this country, the + + align:start position:0% +and 130,000 schools in this country, the + + + align:start position:0% +and 130,000 schools in this country, the +answer to the question, who can buy + + align:start position:0% +answer to the question, who can buy + + + align:start position:0% +answer to the question, who can buy +something is different in all of those + + align:start position:0% +something is different in all of those + + + align:start position:0% +something is different in all of those +contexts. Um, that makes starting an + + align:start position:0% +contexts. Um, that makes starting an + + + align:start position:0% +contexts. Um, that makes starting an +education technology company very very + + align:start position:0% +education technology company very very + + + align:start position:0% +education technology company very very +difficult. + + align:start position:0% +difficult. + + + align:start position:0% +difficult. +Um, when you go somewhere, you don't + + align:start position:0% +Um, when you go somewhere, you don't + + + align:start position:0% +Um, when you go somewhere, you don't +even know who can buy the thing. Um, + + align:start position:0% +even know who can buy the thing. Um, + + + align:start position:0% +even know who can buy the thing. Um, +like you don't even know who you're + + align:start position:0% +like you don't even know who you're + + + align:start position:0% +like you don't even know who you're +selling it to. Now, there are people who + + align:start position:0% +selling it to. Now, there are people who + + + align:start position:0% +selling it to. Now, there are people who +do know who buys all these things. The + + align:start position:0% +do know who buys all these things. The + + + align:start position:0% +do know who buys all these things. The +only people in the United States who + + align:start position:0% +only people in the United States who + + + align:start position:0% +only people in the United States who +know for every school in every district + + align:start position:0% +know for every school in every district + + + align:start position:0% +know for every school in every district +who has the power to buy stuff are giant + + align:start position:0% +who has the power to buy stuff are giant + + + align:start position:0% +who has the power to buy stuff are giant +publishers. Um, Pearson, Hotton, + + align:start position:0% +publishers. Um, Pearson, Hotton, + + + align:start position:0% +publishers. Um, Pearson, Hotton, +Mifflin, what was the company you work + + align:start position:0% +Mifflin, what was the company you work + + + align:start position:0% +Mifflin, what was the company you work +for? McGraill. McGraill. Perfect. They + + align:start position:0% +for? McGraill. McGraill. Perfect. They + + + align:start position:0% +for? McGraill. McGraill. Perfect. They +have an army of salespeople. this army + + align:start position:0% +have an army of salespeople. this army + + + align:start position:0% +have an army of salespeople. this army +of salespeople have fanned out across + + align:start position:0% +of salespeople have fanned out across + + + align:start position:0% +of salespeople have fanned out across +the 13,000 school districts and once a + + align:start position:0% +the 13,000 school districts and once a + + + align:start position:0% +the 13,000 school districts and once a +month, once a quarter, all the people + + align:start position:0% +month, once a quarter, all the people + + + align:start position:0% +month, once a quarter, all the people +who I just listed who can actually buy + + align:start position:0% +who I just listed who can actually buy + + + align:start position:0% +who I just listed who can actually buy +things, they take them out to lunch. + + align:start position:0% +things, they take them out to lunch. + + + align:start position:0% +things, they take them out to lunch. +They bring them free supplies. They do + + align:start position:0% +They bring them free supplies. They do + + + align:start position:0% +They bring them free supplies. They do +all that stuff. They, you know, like + + align:start position:0% +all that stuff. They, you know, like + + + align:start position:0% +all that stuff. They, you know, like +they probably don't have a master list + + align:start position:0% +they probably don't have a master list + + + align:start position:0% +they probably don't have a master list +somewhere. Instead, they have all these + + align:start position:0% +somewhere. Instead, they have all these + + + align:start position:0% +somewhere. Instead, they have all these +sales people who know the answers to + + align:start position:0% +sales people who know the answers to + + + align:start position:0% +sales people who know the answers to +these questions. Um, so if you're a + + align:start position:0% +these questions. Um, so if you're a + + + align:start position:0% +these questions. Um, so if you're a +Silicon Valley startup and you're like, + + align:start position:0% +Silicon Valley startup and you're like, + + + align:start position:0% +Silicon Valley startup and you're like, +"Oh, I know I've got this new like AI + + align:start position:0% +"Oh, I know I've got this new like AI + + + align:start position:0% +"Oh, I know I've got this new like AI +thing I'm building. It's super cool." Da + + align:start position:0% +thing I'm building. It's super cool." Da + + + align:start position:0% +thing I'm building. It's super cool." Da +da da. You don't have this massive + + align:start position:0% +da da. You don't have this massive + + + align:start position:0% +da da. You don't have this massive +network of sales connections to help you + + align:start position:0% +network of sales connections to help you + + + align:start position:0% +network of sales connections to help you +figure this out. Um, one my one of my + + align:start position:0% +figure this out. Um, one my one of my + + + align:start position:0% +figure this out. Um, one my one of my +favorite illustrations of this is at a + + align:start position:0% +favorite illustrations of this is at a + + + align:start position:0% +favorite illustrations of this is at a +bunch of education technology + + align:start position:0% +bunch of education technology + + + align:start position:0% +bunch of education technology +conferences. Um, how many of you ever + + align:start position:0% +conferences. Um, how many of you ever + + + align:start position:0% +conferences. Um, how many of you ever +have been to a conference where they + + align:start position:0% +have been to a conference where they + + + align:start position:0% +have been to a conference where they +have like you have you have a badge, + + align:start position:0% +have like you have you have a badge, + + + align:start position:0% +have like you have you have a badge, +right? And you can put stickers on your + + align:start position:0% +right? And you can put stickers on your + + + align:start position:0% +right? And you can put stickers on your +badges or other things like this. + + align:start position:0% +badges or other things like this. + + + align:start position:0% +badges or other things like this. +Basically, like one of the stickers you + + align:start position:0% +Basically, like one of the stickers you + + + align:start position:0% +Basically, like one of the stickers you +can put on your badge. You can put like + + align:start position:0% +can put on your badge. You can put like + + + align:start position:0% +can put on your badge. You can put like +your pronouns. You can put some other + + align:start position:0% +your pronouns. You can put some other + + + align:start position:0% +your pronouns. You can put some other +things like that. You can put um buyer. + + align:start position:0% +things like that. You can put um buyer. + + + align:start position:0% +things like that. You can put um buyer. +You can basically like signal to people + + align:start position:0% +You can basically like signal to people + + + align:start position:0% +You can basically like signal to people +like I actually have the power to + + align:start position:0% +like I actually have the power to + + + align:start position:0% +like I actually have the power to +purchase things. Um and then when you w + + align:start position:0% +purchase things. Um and then when you w + + + align:start position:0% +purchase things. Um and then when you w +you know um uh if you know when you walk + + align:start position:0% +you know um uh if you know when you walk + + + align:start position:0% +you know um uh if you know when you walk +through the exhibit hall they will pay + + align:start position:0% +through the exhibit hall they will pay + + + align:start position:0% +through the exhibit hall they will pay +more attention to the people who have + + align:start position:0% +more attention to the people who have + + + align:start position:0% +more attention to the people who have +the little buyer things on them than + + align:start position:0% +the little buyer things on them than + + + align:start position:0% +the little buyer things on them than +they will to like you know critical + + align:start position:0% +they will to like you know critical + + + align:start position:0% +they will to like you know critical +social science researcher badge um is + + align:start position:0% +social science researcher badge um is + + + align:start position:0% +social science researcher badge um is +put on your thing or something like + + align:start position:0% +put on your thing or something like + + + align:start position:0% +put on your thing or something like +that. So that is an incred so um here + + align:start position:0% +that. So that is an incred so um here + + + align:start position:0% +that. So that is an incred so um here +are some things that you should take + + align:start position:0% +are some things that you should take + + + align:start position:0% +are some things that you should take +away. These these systems are incredibly + + align:start position:0% +away. These these systems are incredibly + + + align:start position:0% +away. These these systems are incredibly +complicated. There are all kinds of + + align:start position:0% +complicated. There are all kinds of + + + align:start position:0% +complicated. There are all kinds of +stakeholders in them but they're they're + + align:start position:0% +stakeholders in them but they're they're + + + align:start position:0% +stakeholders in them but they're they're +not so infinite. they're not so complex + + align:start position:0% +not so infinite. they're not so complex + + + align:start position:0% +not so infinite. they're not so complex +that we can't like make a chart that + + align:start position:0% +that we can't like make a chart that + + + align:start position:0% +that we can't like make a chart that +sort of manages and starts to understand + + align:start position:0% +sort of manages and starts to understand + + + align:start position:0% +sort of manages and starts to understand +all these things. Um but as we move + + align:start position:0% +all these things. Um but as we move + + + align:start position:0% +all these things. Um but as we move +forward and as we um look at more sort + + align:start position:0% +forward and as we um look at more sort + + + align:start position:0% +forward and as we um look at more sort +of you know a thing that a thing that + + align:start position:0% +of you know a thing that a thing that + + + align:start position:0% +of you know a thing that a thing that +you can do in any kind of education + + align:start position:0% +you can do in any kind of education + + + align:start position:0% +you can do in any kind of education +technology problem any educational + + align:start position:0% +technology problem any educational + + + align:start position:0% +technology problem any educational +setting be like all right who are going + + align:start position:0% +setting be like all right who are going + + + align:start position:0% +setting be like all right who are going +to be the stakeholders for this problem + + align:start position:0% +to be the stakeholders for this problem + + + align:start position:0% +to be the stakeholders for this problem +this thing and what are going to be + + align:start position:0% +this thing and what are going to be + + + align:start position:0% +this thing and what are going to be +their interests. Um the more you know + + align:start position:0% +their interests. Um the more you know + + + align:start position:0% +their interests. Um the more you know +and not you know again not just like + + align:start position:0% +and not you know again not just like + + + align:start position:0% +and not you know again not just like +their official interest their official + + align:start position:0% +their official interest their official + + + align:start position:0% +their official interest their official +like state policy interest is to raise + + align:start position:0% +like state policy interest is to raise + + + align:start position:0% +like state policy interest is to raise +test scores or something like that. Um + + align:start position:0% +test scores or something like that. Um + + + align:start position:0% +test scores or something like that. Um +but one of my favorite examples um that + + align:start position:0% +but one of my favorite examples um that + + + align:start position:0% +but one of my favorite examples um that +we're talking about is uh televisions + + align:start position:0% +we're talking about is uh televisions + + + align:start position:0% +we're talking about is uh televisions +were more likely to be used at the end + + align:start position:0% +were more likely to be used at the end + + + align:start position:0% +were more likely to be used at the end +of the day because people were tired. Um + + align:start position:0% +of the day because people were tired. Um + + + align:start position:0% +of the day because people were tired. Um +like your body's circadian rhythm um + + align:start position:0% +like your body's circadian rhythm um + + + align:start position:0% +like your body's circadian rhythm um +indicates how technologies be used in + + align:start position:0% +indicates how technologies be used in + + + align:start position:0% +indicates how technologies be used in +classroom. And that is just as real is + + align:start position:0% +classroom. And that is just as real is + + + align:start position:0% +classroom. And that is just as real is +just as real as the policy mandate to + + align:start position:0% +just as real as the policy mandate to + + + align:start position:0% +just as real as the policy mandate to +raise test scores um or the school + + align:start position:0% +raise test scores um or the school + + + align:start position:0% +raise test scores um or the school +board's enthusiasm for technology or + + align:start position:0% +board's enthusiasm for technology or + + + align:start position:0% +board's enthusiasm for technology or +whatever it is. Um and so we we can in + + align:start position:0% +whatever it is. Um and so we we can in + + + align:start position:0% +whatever it is. Um and so we we can in +any kind of system we can figure out who + + align:start position:0% +any kind of system we can figure out who + + + align:start position:0% +any kind of system we can figure out who +are the stakeholders in the system. What + + align:start position:0% +are the stakeholders in the system. What + + + align:start position:0% +are the stakeholders in the system. What +are the interests of those things? What + + align:start position:0% +are the interests of those things? What + + + align:start position:0% +are the interests of those things? What +are the disinterests? A thing is more + + align:start position:0% +are the disinterests? A thing is more + + + align:start position:0% +are the disinterests? A thing is more +likely to work if it attends to those + + align:start position:0% +likely to work if it attends to those + + + align:start position:0% +likely to work if it attends to those +real meaningful felt interests and if it + + align:start position:0% +real meaningful felt interests and if it + + + align:start position:0% +real meaningful felt interests and if it +avoids those real meaningful felt + + align:start position:0% +avoids those real meaningful felt + + + align:start position:0% +avoids those real meaningful felt +disinterests. And of course we're doing + + align:start position:0% +disinterests. And of course we're doing + + + align:start position:0% +disinterests. And of course we're doing +this like in a very detailed way in + + align:start position:0% +this like in a very detailed way in + + + align:start position:0% +this like in a very detailed way in +education. But if you were to let leave + + align:start position:0% +education. But if you were to let leave + + + align:start position:0% +education. But if you were to let leave +education and you were to go into + + align:start position:0% +education and you were to go into + + + align:start position:0% +education and you were to go into +healthcare, if you were to go into legal + + align:start position:0% +healthcare, if you were to go into legal + + + align:start position:0% +healthcare, if you were to go into legal +technology, if you were going to retail, + + align:start position:0% +technology, if you were going to retail, + + + align:start position:0% +technology, if you were going to retail, +you can do the exact same exercise. um + + align:start position:0% +you can do the exact same exercise. um + + + align:start position:0% +you can do the exact same exercise. um +the technology that you're building for + + align:start position:0% +the technology that you're building for + + + align:start position:0% +the technology that you're building for +a hospital, like it has to work for a + + align:start position:0% +a hospital, like it has to work for a + + + align:start position:0% +a hospital, like it has to work for a +doctor, but it has to work for a nurse + + align:start position:0% +doctor, but it has to work for a nurse + + + align:start position:0% +doctor, but it has to work for a nurse +and an orderly and a patient and the + + align:start position:0% +and an orderly and a patient and the + + + align:start position:0% +and an orderly and a patient and the +patient's representative and the + + align:start position:0% +patient's representative and the + + + align:start position:0% +patient's representative and the +hospital's lawyers and all these + + align:start position:0% +hospital's lawyers and all these + + + align:start position:0% +hospital's lawyers and all these +different kinds of people. Um and so, + + align:start position:0% +different kinds of people. Um and so, + + + align:start position:0% +different kinds of people. Um and so, +you know, on the one hand, especially + + align:start position:0% +you know, on the one hand, especially + + + align:start position:0% +you know, on the one hand, especially +when people are designers of software, + + align:start position:0% +when people are designers of software, + + + align:start position:0% +when people are designers of software, +we can have this sense of like, oh, I'm + + align:start position:0% +we can have this sense of like, oh, I'm + + + align:start position:0% +we can have this sense of like, oh, I'm +building things for a user. I'm building + + align:start position:0% +building things for a user. I'm building + + + align:start position:0% +building things for a user. I'm building +things for like this individual user + + align:start position:0% +things for like this individual user + + + align:start position:0% +things for like this individual user +who's got their fingers on their + + align:start position:0% +who's got their fingers on their + + + align:start position:0% +who's got their fingers on their +keyboard or their thumb on the screen or + + align:start position:0% +keyboard or their thumb on the screen or + + + align:start position:0% +keyboard or their thumb on the screen or +something like that. Um, but I would + + align:start position:0% +something like that. Um, but I would + + + align:start position:0% +something like that. Um, but I would +encourage you as we're thinking through + + align:start position:0% +encourage you as we're thinking through + + + align:start position:0% +encourage you as we're thinking through +all these things to to think about these + + align:start position:0% +all these things to to think about these + + + align:start position:0% +all these things to to think about these +networks of interests and stakeholders + + align:start position:0% +networks of interests and stakeholders + + + align:start position:0% +networks of interests and stakeholders +much more broadly. Okay. Um, we'll talk + + align:start position:0% +much more broadly. Okay. Um, we'll talk + + + align:start position:0% +much more broadly. Okay. Um, we'll talk +to some education school deans on + + align:start position:0% +to some education school deans on + + + align:start position:0% +to some education school deans on +Wednesday. We'll learn a little bit + + align:start position:0% +Wednesday. We'll learn a little bit + + + align:start position:0% +Wednesday. We'll learn a little bit +about uh implementation, how you + + align:start position:0% +about uh implementation, how you + + + align:start position:0% +about uh implementation, how you +overcome some of these kinds of + + align:start position:0% +overcome some of these kinds of + + + align:start position:0% +overcome some of these kinds of +challenges from me. We'll hear a little + + align:start position:0% +challenges from me. We'll hear a little + + + align:start position:0% +challenges from me. We'll hear a little +bit about the National Education + + align:start position:0% +bit about the National Education + + + align:start position:0% +bit about the National Education +Technology Plan. Um, and I will pair you + + align:start position:0% +Technology Plan. Um, and I will pair you + + + align:start position:0% +Technology Plan. Um, and I will pair you +up with each other um to be able to do + + align:start position:0% +up with each other um to be able to do + + + align:start position:0% +up with each other um to be able to do +some peer editing of your essays and + + align:start position:0% +some peer editing of your essays and + + + align:start position:0% +some peer editing of your essays and +that will get us through the week. Sound + + align:start position:0% +that will get us through the week. Sound + + + align:start position:0% +that will get us through the week. Sound +good? Bueno, let me know if I can help + + align:start position:0% +good? Bueno, let me know if I can help + + + align:start position:0% +good? Bueno, let me know if I can help +you with anything. Otherwise, have a + + align:start position:0% +you with anything. Otherwise, have a + + + align:start position:0% +you with anything. Otherwise, have a +wonderful rest of your afternoon. \ No newline at end of file diff --git a/6XV3uLfKzog.txt b/6XV3uLfKzog.txt new file mode 100644 index 0000000000000000000000000000000000000000..f9f6d4b1195e102b5eb07ca8dd28b7c85d67c72f --- /dev/null +++ b/6XV3uLfKzog.txt @@ -0,0 +1,527 @@ +The data path diagram isn't all that useful +in diagramming the pipelined execution of + +an instruction sequence since we need a new +copy of the diagram for each clock cycle. + +A more compact and easier-to-read diagram +of pipelined execution is provided by the + +pipeline diagrams we met back in Part 1 of +the course. + +There's one row in the diagram for each pipeline +stage and one column for each cycle of execution. + +Entries in the table show which instruction +is in each pipeline stage at each cycle. + +In normal operation, a particular instruction +moves diagonally through the diagram as it + +proceeds through the five pipeline stages. + +To understand data hazards, let's first remind +ourselves of when the register file is read + +and written for a particular instruction. + +Register reads happen when the instruction +is in the RF stage, i.e., when we're reading + +the instruction's register operands. + +Register writes happen at the end of the cycle +when the instruction is in the WB stage. + +For example, for the first LD instruction, +we read R1 during cycle 2 and write R2 at + +the end of cycle 5. + +Or consider the register file operations in +cycle 6: + +we're reading R12 and R13 for the MUL instruction +in the RF stage, and writing R4 at the end + +of the cycle for the LD instruction in the +WB stage. + +Okay, now let's see what happens when there +are data hazards. + +In this instruction sequence, the ADDC instruction +writes its result in R2, which is immediately + +read by the following SUBC instruction. + +Correct execution of the SUBC instruction +clearly depends on the results of the ADDC + +instruction. + +This what we'd call a read-after-write dependency. + +This pipeline diagram shows the cycle-by-cycle +execution where we've circled the cycles during + +which ADDC writes R2 and SUBC reads R2. + +Oops! + +ADDC doesn't write R2 until the end of cycle +5, but SUBC is trying to read the R2 value + +in cycle 3. + +The value in R2 in the register file in cycle +3 doesn't yet reflect the execution of the + +ADDC instruction. + +So as things stand the pipeline would *not* +correctly execute this instruction sequence. + +This instruction sequence has triggered a +data hazard. + +We want the pipelined CPU to generate the +same program results as the unpipelined CPU, + +so we'll need to figure out a fix. + +There are three general strategies we can +pursue to fix pipeline hazards. + +Any of the techniques will work, but as we'll +see they have different tradeoffs for instruction + +throughput and circuit complexity. + +The first strategy is to stall instructions +in the RF stage until the result they need + +has been written to the register file. + +"Stall" means that we don't reload the instruction +register at the end of the cycle, so we'll + +try to execute the same instruction in the +next cycle. + +If we stall one pipeline stage, all earlier +stages must also be stalled since they are + +blocked by the stalled instruction. + +If an instruction is stalled in the RF stage, +then the IF stage is also stalled. + +Stalling will always work, but has a negative +impact on instruction throughput. + +Stall for too many cycles and you'll loose +the performance advantages of pipelined execution! + +The second strategy is to route the needed +value to earlier pipeline stages as soon as + +its computed. + +This called bypassing or forwarding. + +As it turns out, the value we need often exists +somewhere in the pipelined data path, it just + +hasn't been written yet to the register file. + +If the value exists and can be forwarded to +where it's needed, we won't need to stall. + +We'll be able to use this strategy to avoid +stalling on most types of data hazards. + +The third strategy is called speculation. + +We'll make an intelligent guess for the needed +value and continue execution. + +Once the actual value is determined, if we +guessed correctly, we're all set. + +If we guessed incorrectly, we have to back +up execution and restart with the correct + +value. + +Obviously speculation only makes sense if +it's possible to make accurate guesses. + +We'll be able to use this strategy to avoid +stalling on control hazards. + +Let's see how the first two strategies work +when dealing with our data hazard. + +Applying the stall strategy to our data hazard, +we need to stall the SUBC instruction in the + +RF stage until the ADDC instruction writes +its result in R2. + +So in the pipeline diagram, SUBC is stalled +three times in the RF stage until it can finally + +access the R2 value from the register file +in cycle 6. + +Whenever the RF stage is stalled, the IF stage +is also stalled. + +You can see that in the diagram too. + +But when RF is stalled, what should the ALU +stage do in the next cycle? + +The RF stage hasn't finished its job and so +can't pass along its instruction! + +The solution is for the RF stage to make-up +an innocuous instruction for the ALU stage, + +what's called a NOP instruction, short for +"no operation". + +A NOP instruction has no effect on the CPU +state, i.e., it doesn't change the contents + +of the register file or main memory. + +For example any OP-class or OPC-class instruction +that has R31 as its destination register is + +a NOP. + +The NOPs introduced into the pipeline by the +stalled RF stage are shown in red. + +Since the SUBC is stalled in the RF stage +for three cycles, three NOPs are introduced + +into the pipeline. + +We sometimes refer to these NOPs as "bubbles" +in the pipeline. + +How does the pipeline know when to stall? + +It can compare the register numbers in the +RA and RB fields of the instruction in the + +RF stage with the register numbers in the +RC field of instructions in the ALU, MEM, + +and WB stage. + +If there's a match, there's a data hazard +and the RF stage should be stalled. + +The stall will continue until there's no hazard +detected. + +There are a few details to take care of: +some instructions don't read both registers, + +the ST instruction doesn't use its RC field, +and we don't want R31 to match since it's + +always okay to read R31 from the register +file. + +Stalling will ensure correct pipelined execution, +but it does increase the effective CPI. + +This will lead to longer execution times if +the increase in CPI is larger than the decrease + +in cycle time afforded by pipelining. + +To implement stalling, we only need to make +two simple changes to our pipelined data path. + +We generate a new control signal, STALL, which, +when asserted, disables the loading of the + +three pipeline registers at the input of the +IF and RF stages, which means they'll have + +the same value next cycle as they do this +cycle. + +We also introduce a mux to choose the instruction +to be sent along to the ALU stage. + +If STALL is 1, we choose a NOP instruction, +e.g., an ADD with R31 as its destination. + +If STALL is 0, the RF stage is not stalled, +so we pass its current instruction to the + +ALU. + +And here we see how to compute STALL as described +in the previous slide. + +The additional logic needed to implement stalling +is pretty modest, so the real design tradeoff + +is about increased CPI due to stalling vs. +decreased cycle time due to pipelining. + +So we have a solution, although it carries +some potential performance costs. + +Now let's consider our second strategy: +bypassing, which is applicable if the data + +we need in the RF stage is somewhere in the +pipelined data path. + +In our example, even though ADDC doesn't write +R2 until the end of cycle 5, the value that + +will be written is computed during cycle 3 +when the ADDC is in the ALU stage. + +In cycle 3, the output of the ALU is the value +needed by the SUBC that's in the RF stage + +in the same cycle. + +So, if we detect that the RA field of the +instruction in the RF stage is the same as + +the RC field of the instruction in the ALU +stage, we can use the output of the ALU in + +place of the (stale) RA value being read from +the register file. + +No stalling necessary! + +In our example, in cycle 3 we want to route +the output of the ALU to the RF stage to be + +used as the value for R2. + +We show this with a red "bypass arrow" showing +data being routed from the ALU stage to the + +RF stage. + +To implement bypassing, we'll add a many-input +multiplexer to the read ports of the register + +file so we can select the appropriate value +from other pipeline stages. + +Here we show the combinational bypass paths +from the ALU, MEM, and WB stages. + +For the bypassing example of the previous +slides, we use the blue bypass path during + +cycle 3 to get the correct value for R2. + +The bypass muxes are controlled by logic that's +matching the number of the source register + +to the number of the destination registers +in the ALU, MEM, and WB stages, with the usual + +complications of dealing with R31. + +What if there are multiple matches, i.e., +if the RF stage is trying to read a register + +that's the destination for, say, the instructions +in both the ALU and MEM stages? + +No problem! + +We want to select the result from the most +recent instruction, so we'd chose the ALU + +match if there is one, then the MEM match, +then the WB match, then, finally, the output + +of the register file. + +Here's diagram showing all the bypass paths +we'll need. + +Note that branches and jumps write their PC+4 +value into the register file, so we'll need + +to bypass from the PC+4 values in the various +stages as well as the ALU values. + +Note that the bypassing is happening at the +end of the cycle, e.g., after the ALU has + +computed its answer. + +To accommodate the extra t_PD of the bypass +mux, we'll have to extend the clock period + +by a small amount. + +So once again there's a design tradeoff - the +increased CPI of stalling vs the slightly + +increased cycle time of bypassing. + +And, of course, in the case of bypassing there's +the extra area needed for the necessary wiring + +and muxes. + +We can cut back on the costs by reducing the +amount of bypassing, say, to only bypassing + +ALU results from the ALU stage and use stalling +to deal with all the other data hazards. + +If we implement full bypassing, do we still +need the STALL logic? + +As it turns out, we do! + +There's one data hazard that bypassing doesn't +completely address. + +Consider trying to immediately the use the +result of a LD instruction. + +In the example shown here, the SUBC is trying +to use the value the immediately preceding + +LD is writing to R2. + +This is called a load-to-use hazard. + +Recalling that LD data isn't available in +the data path until the cycle when LD reaches + +the WB stage, even with full bypassing we'll +need to stall SUBC in the RF stage until cycle + +5, introducing two NOPs into the pipeline. + +Without bypassing from the WB stage, we need +to stall until cycle 6. + +In summary, we have two strategies for dealing +with data hazards. + +We can stall the IF and RF stages until the +register values needed by the instruction + +in the RF stage are available in the register +file. + +The required hardware is simple, but the NOPs +introduced into the pipeline waste CPU cycles + +and result in an higher effective CPI. + +Or we can use bypass paths to route the required +values to the RF stage assuming they exist + +somewhere in the pipelined data path. + +This approach requires more hardware than +stalling, but doesn't reduce the effective + +CPI. + +Even if we implement bypassing, we'll still +need stalls to deal with load-to-use hazards. + +Can we keep adding pipeline stages in the +hopes of further reducing the clock period? + +More pipeline stages mean more instructions +in the pipeline at the same time, which in + +turn increases the chance of a data hazard +and the necessity of stalling, thus increasing + +CPI. + +Compilers can help reduce dependencies by +reorganizing the assembly language code they + +produce. + +Here's the load-to-use hazard example we saw +earlier. + +Even with full bypassing, we'd need to stall +for 2 cycles. + +But if the compiler (or assembly language +programmer!) notices that the MUL and XOR + +instructions are independent of the SUBC instruction +and hence can be moved before the SUBC, + +the dependency is now such that the LD is +naturally in the WB stage when the SUBC is + +in the RF stage, so no stalls are needed. + +This optimization only works when the compiler +can find independent instructions to move + +around. + +Unfortunately there are plenty of programs +where such instructions are hard to find. + +Then there's one final approach we could take +- + +change the ISA so that data hazards are part +of the ISA, i.e., just explain that writes + +to the destination register happen with a +3-instruction delay! + +If NOPs are needed, make the programmer add +them to the program. + +Simplify the hardware at the "small" cost +of making the compilers work harder. + +You can imagine exactly how much the compiler +writers will like this suggestion. + +Not to mention assembly language programmers! + +And you can change the ISA again when you +add more pipeline stages! + +This is how a compiler writer views CPU architects +who unilaterally change the ISA to save a + +few logic gates :) +The bottom line is that successful ISAs have + +very long lifetimes and so shouldn't include +tradeoffs driven by short-term implementation + +considerations. + +Best not to go there. \ No newline at end of file diff --git a/6gMgNriK1Nk.txt b/6gMgNriK1Nk.txt new file mode 100644 index 0000000000000000000000000000000000000000..a47aba0981ac22019b367bc98ffbb19e5c5dac11 --- /dev/null +++ b/6gMgNriK1Nk.txt @@ -0,0 +1,3476 @@ +The following +content is provided + +under a Creative +Commons license. + +Your support will help MIT +OpenCourseWare continue + +to offer high quality +educational resources for free. + +To make a donation or +view additional materials + +from hundreds of MIT courses, +visit MIT OpenCourseWare + +at ocw.mit.edu. + +PROFESSOR: So last +time we started + +talking about superfluid helium. + +And we said that the +phase diagram of helium-4, + +the isotope that is a boson +has the following interesting + +properties. + +First of all, helium +stays a liquid + +all the way down +to 0 temperature + +because of the combinations +of its light mass and heat + +interactions. + +And secondly, that [INAUDIBLE] +to cool down helium + +through this process +of evaporated cooling, + +one immediately observes +something interesting + +happening at temperatures +below 2 degrees + +Kelvin, where it becomes +this superfluid that + +has a number of +interesting properties. + +And in particular as +pertaining to viscosity, + +we made two observations. + +First of all, you can +make these capillaries-- + +and I'll show you been +movie in more detail later + +on where it flows through +capillaries as if there + +is no resistance +and there is nothing + +that sticks to the walls +of the capillaries. + +It flows without +viscosity, whereas there + +was this experiment of +Andronikashvili, in which you + +had something that +was oscillating + +and you were calculating +how much of the helium + +was stuck to the plates +of the container. + +And the result was +something like this, + +that is there was a decrease +in the amount of fluid + +that is stuck to the plates. + +But it doesn't go +immediately down to 0. + +It has a kind of +form such as this + +that I will draw more +clearly now and explain. + +So what we did last time was +to note that people observed + +that there were +some similarities + +between this +superfluid transition + +and Bose-Einstein condensation. + +But what I would +like to highlight + +in the beginning +of this lecture is + +that there are also very +important differences. + +So let's think about +these distinctions + +between Bose-Einstein condensate +add the superfluid helium. + +One set of things we would +like to take from the picture + +that I have over there, which +is diffraction of the fluid that + +is stuck to the plates +and in some sense + +behaves like a normal fluid. + +Now let me make the analogy +to Bose-Einstein condensation. + +You know that in the +Bose-Einstein condensation + +there was also this phenomenon +that there was a separation + +into two parts of +the total density. + +And be regarded as a +function of temperature + +some part of the density as +belonging to the normal state. + +So when you are above +Tc of n, everything + +is essentially normal. + +And then what happens is +that when you hit Tc of n + +you can no longer put +all of the particles + +that you have in +the excited states. + +So the fraction that goes +in the excited states + +goes down and eventually +goes to 0 at 0 temperature. + +And essentially, this would +be the reverse of the curve + +that we have in that +figure over there. + +Basically, there's +a portion that + +would be the normal part that +would be looking like this. + +Now, the way that we +obtained this result + +was that basically there +was a fraction that + +was in the normal state. + +The part that was +excited was described + +by this simple formula that was +g over lambda cubed [INAUDIBLE] + +of 3/2. + +So it went to 0 as T to the 3/2. + +So basically, the +proportionality + +here is T to the 3/2. + +And then basically, +the curve would + +come down here and +go to 0 linearly. + +Now what is shown +in the experiment + +is that the curve +actually goes to 0 + +in a much more sharp fashion. + +And actually, when people try +to fit a curve through this, + +the curve looks something like +Tc minus T to the 2/3 over. + +But also it goes to 0 much +more rapidly than the curve + +that we have for +Bose-Einstein condensation. + +Indeed, it goes through +0 proportionately to T + +to the fourth. + +And so that's something that we +need to understand and explain. + +Now all of the properties of +the Bose-Einstein condensate + +was very easy to +describe once we realized + +that all of the things that +correspond to excitation, + +such as the energy, +heat capacity, + +pressure, come from +this fraction that + +is in the excited state. + +And we can calculate, +say, the contribution + +to energy heat +capacity, et cetera. + +And in particular, if we look +at the behavior of the heat + +capacity as a function +of temperature, + +for this Bose-Einstein +condensate, the behavior + +that we had was that again +simply at low temperatures + +it was going proportionately +to T to the 3/2, + +because this was the number +of excitations that you had. + +So these two T to the +3/2 are very much related + +to each other. + +And then this curve would +basically go along its way + +until it hit Tc of +n at some point. + +And we separately +calculated the behavior + +coming from high temperatures. + +And the behavior from +high temperatures + +would start with +the classical result + +that the heat capacity +is 3/2 per particle + +due to the kinetic energy that +you can put in these things. + +And then it would rise, and it +would then join this curve over + +here. + +Now when you look at the +actual heat capacity, + +indeed the shape up +the heat capacity + +is the thing that gives this +transition the name of a lambda + +transition. + +It kind of looks like a lambda. + +And at Tc there are +divergences approaching + +from the two sides that +behave like the log. + +And again more +importantly, what we + +find is that at +0 temperature, it + +doesn't go through 0, the +heat capacity as T to the 3/2, + +but rather as T to +the third power. + +So the red curve +corresponds to superfluid, + +the green curve corresponds +to Bose-Einstein condensate. + +And so they're clearly +different from each other. + +So that's what we would +like you to understand. + +Well the thing that is easiest +to understand and figure out + +is the difference between +these heat capacities. + +And the reason for that +is that we had already + +seen a form that was of +the heat capacity that + +behaved like T cubed. + +That was when we were looking +at phonons in a solid. + +So let's remind +you why was it that + +for the Bose-Einstein +condensate we + +were getting this T +to the 3/2 behavior? + +The reason for that was that +the various excitations, + +I could plot as a function +of k, or p, which is h bar k. + +They're very much +related to each other. + +And for the +Bose-Einstein condensate, + +the form was simply +a parabola, which + +is this p squared over +2 mass of the helium. + +Let's say, assuming that +what we are dealing with + +is non-interacting particles +with mass of helium. + +And this parabolic +curve essentially + +told us that various quantities +behave as T to the 3/2. + +Roughly, the idea is that +at some temperature that + +has energy of the order +of kT, you figure out + +how far you have excited things. + +And since this +form is a parabola, + +the typical p is going to +scale like T to the 1/2. + +You have a volume in three +dimensions in p space. + +If the radius goes +like T to the 1/2, + +the volume goes +like T to the 3/2. + +That's why you have all kinds +of excitations such as this. + +And the reason for the +Bose-Einstein condensation + +was that you would start to fill +out all of these excitations. + +And when you were adding all +of the mean occupation numbers, + +the answer was not +coming up all the way + +to the total number +of particles. + +So then you have to put +an excess at p close + +to 0, which corresponds to the +ground state of this system. + +Now of course when +you look at helium, + +helium molecules, helium +atoms have the interactions + +between them that we discussed. + +In particular, you can't really +put them on top of each other. + +There is a hard exclusion +when you bring things + +close to each other. + +So the ground +state of the system + +must look very different +from the ground state + +of the Bose-Einstein condensate +in which the particles freely + +occupy the entire box. + +So there is a very +difficult story + +associated with +figuring out what + +the ground state of this +combination of interacting + +particles that make +up liquid helium is. + +What is the behavior? + +What's the many-body wave +function at 0 temperature? + +Now as we see here, in order +to understand the heat capacity + +we really don't +need to know what + +is happening at +the ground state. + +What we need to know in +order to find heat capacity + +is how to put more energy in the +system above the ground state. + +So we need to know +something about excitations. + +And so that's the +perspective that Landau took. + +Landau said, well, this is +the spectrum of excitations + +if you had [? plain ?] particles +without any interactions. + +Let's imagine what +happens if we gradually + +tune in the interactions, +the particles + +start to repel each +other, et cetera. + +This non-interacting +ground state + +that we had in which the +particles were uniformly + +distributed across +the system will + +evolve into some complicated +ground state I don't know. + +And then, presumably +there would be a spectrum + +of excitations around +that ground state. + +Now the excitations around +the non-interacting ground + +state we can label by +this momentum peak. + +And it kind of +makes sense that we + +should be able to have a +singular label for excitations + +around the ground state of +these interacting particles. + +And this is where +you sort of needed + +a little bit of Landau's +type of insight. + +He said, well, +presumably what you + +do when you have +excitations of momentum p + +is to distort the wave +function in a manner that + +is consistent with having these +kind of excitations of momentum + +p. + +And he said, well +we typically know + +that if you have +a fluid or a solid + +and we want to impart some +momentum above the ground + +state, if will go in +the form of phonons. + +These are distortions in +which the density will + +vary in some sinusoidal or +cosine way across the system. + +So he said that maybe +what is happening + +is that for these +excitations you + +have to take what ever this +interacting ground state is-- + +which we don't know and +can't write that down-- + +but hope that +excitations around it + +correspond to these +distortions in density. + +And that by analogy with +what happens for fluids, + +that the spectrum of excitations +will then become a linear. + +You would have something +like a sound wave + +that you would have in +a liquid or a solid. + +So if you do this, if you +have a linear spectrum + +then we can see what happen. + +For a particular energy +of the order of kT, + +we will go here, +occupied momenta that + +would be of the order +of kT over H bar. + +The number of excitations would +be something like this cubed, + +and so you would +imagine that you + +would get a heat capacity that +is proportional to this times + +kB. + +And if you do things +correctly, like really + +for the case of +phonons or photons, + +you can even figure out what +the numerical prefactor is here. + +And there's a velocity +here because this curve + +goes like H bar vP. + +So then you can +compare what you have + +over here with the coefficient +of the T cubed over here, + +and you could even figure +out what this velocity is. + +And it turns out to be of the +order of 240 meters per second. + +A typical sound wave that +you would have in a fluid. + +So that's kind of +a reasonable thing. + +Now of course, when you go +to higher and higher momenta, + +it corresponds to essentially +shorter and shorter + +wavelengths. + +You expect that when +you get wavelengths + +that is of the order of +the interatomic spacing, + +then the interactions become +less and less important. + +You have particles +rattling in a cage + +that is set up by +everybody else. + +And then you should regain +this kind of spectrum + +at high values of momentum. + +And so what Landau +did was he basically + +joined these things +together and posed + +that there is a spectrum +such as this that + +has what is called +a phonon part, which + +is this linear part where +energy goes like H bar, + +like the velocity +times the momentum. + +And it has a part that in +the vicinity of this point, + +you can expand parabolically. + +And it's called rotons. + +There is a gap +delta, and then H bar + +squared over 2, some effective +mass, k minus k0 squared. + +This k0 turns out to +be roughly of the order + +of the inverse +[INAUDIBLE], two Angstrom + +inverse, between particles. + +This mu is of the order +of mass of [INAUDIBLE]. + +So about 10 years +or so after Landau, + +people are able to get to this +whole spectrum of excitation + +through neutron scattering +and other scattering + +types of experiments. + +And so this picture +was confirmed. + +So, yes? + +AUDIENCE: What is a +roton? [INAUDIBLE] + +PROFESSOR: Over here +what you are seeing + +is essentially particles +rattling in the cage. + +It is believed that +what is happening here + +are collections of +three or four atoms that + +are kind of rotating +in a bigger cage. + +So something, the +picture that people draw + +is three or four +particles rotating around. + +Yes? + +AUDIENCE: Is there +some [INAUDIBLE] curve + +where energy's +decreasing [INAUDIBLE]? + +Does the transition between +photon and roton [INAUDIBLE]? + +PROFESSOR: There is no +thermodynamic or other rule + +that says that the energy should +be one of [INAUDIBLE] momentum + +that I know. + +Yes? + +AUDIENCE: Is there an +expression for that k0 + +in terms of temperature and +other properties of the system? + +PROFESSOR: This +curve of excitations + +is supposed to be property +of the ground state. + +That is, you take this +system in its ground state, + +and then you create +an excitation that + +has some particular +momentum and calculate + +what the energy of that is. + +Actually, this whole +curve is phenomenological, + +because in order to get +the excitations you better + +have an expression for +what the ground state is. + +And so writing a +kind of wave function + +that describes the ground state +of this interacting system + +is a very difficult task. + +I think Feynman has some +variational type of wave + +function that we can start +and work with, and then + +calculate things approximately +in terms of that. + +Yes? + +AUDIENCE: What inspired +Landau to propose + +that there was a [INAUDIBLE]? + +PROFESSOR: Actually, +it was not so much + +I think looking at +this curve, but which + +I think if you +want to match that + +and that, you have to +have something like this. + +But this was really that the +whole experimental version + +of the heat capacity, +it didn't seem + +like this expression +was sufficient. + +And then there was some amount +of excitation and energy + +at the temperatures that were +experimentally accessible + +that heated at the presence +of the rotons in the spectrum. + +Yes? + +AUDIENCE: So +continuing [INAUDIBLE], + +if you raise the thermal energy +kBT, [INAUDIBLE] level where + +you have multiple +roots of this curve. + +PROFESSOR: Yes. + +AUDIENCE: So you will be +able to excite some states + +and have some kind of gap, like +a gap of momenta which are not. + +PROFESSOR: OK, so at any +finite temperatures-- and I'll + +do the calculation for +you shortly-- there + +is a finite probability for +exciting all of these states. + +What you are saying +is that when there + +is more occupation at this +momentum compared to that, + +but much less compared to this. + +So that again does not +violate any condition. + +So it is like, again, trying to +shake this system of particles. + +Let's imagine that +you have grains, + +and you are trying +to shake them. + +And it may be that at +some shaking frequencies, + +then there are things +that are taking place + +at short distances in +addition to some waves + +that you're generating. + +Yeah? + +AUDIENCE: I have a question +about the methodology + +of getting this +spectrum, because if we + +have a experimental result +of the [INAUDIBLE] capacity, + +then if we assume +there's a spectrum, + +there has to be +this one, because it + +gives a one to one +correspondence. + +So we can get the spectrum +directly from the c. + +So-- + +PROFESSOR: I'm not sure, +because in reality this + +is going to be spectrum in +three-dimensional space. + +And there is certainly +an expression + +that relates the heat capacity +to the excitation spectrum. + +What I'm not sure is +whether mathematically + +that expression +uniquely invertible. + +It is given an epsilon-- c, +you have a unique epsilon of p. + +Certainly, given an epsilon +of p, you have a unique c. + +Yes? + +AUDIENCE: But if the excitation +spectrum only depends on, + +let's say, k squared, not on +the three-dimensional components + +of k, then maybe +it's much easier + +to draw a one to +one correspondence? + +PROFESSOR: I don't +know, because you + +have a function of +temperature and you + +want to convert it to +a function of momentum + +that after some +integrations will give you + +that function of temperature. + +I don't know the difficulty +of mathematically doing that. + +I know that I can't off my head +think of an inversion formula. + +It's not like the function +that you're inversing. + +So the Landau spectrum +can explain this part. + +It turns out that the Landau +spectrum cannot explain this + +logarithmic divergence. + +Yes? + +AUDIENCE: Sorry, one +more question about this. + +The allowed values of +k, do they get modified, + +or are they thought +to be the same? + +PROFESSOR: No. + +So basically at some point, +I have to change perspective + +from a sum over k to an integral +over k or an integral over p. + +The density of +states in momentum + +is something that is +kind of invariant. + +It is a very slight +function of shape. + +So the periodic +boundary conditions + +and the open boundary +conditions, et cetera, + +give you something slightly +different over here. + +But by the time you +go to the continuum, + +it's a property +of dimension only. + +It doesn't really depend +on the underlying shape. + +AUDIENCE: So we +still change sums + +for integrals with +the same rules? + +PROFESSOR: Yes. + +It's a sort of general +density of state property. + +So there's some nice +formula that tells you + +what the density of state +is for an arbitrary shape, + +and the leading term is +always proportional to volume + +or area [INAUDIBLE] +the density of state + +that you have been calculating. + +And then there are +some leading terms + +that are proportional to +if it is volume to area, + +or number of edges, et cetera. + +But those are kind of subleading +the thermodynamic sense. + +So I guess Feynman +did a lot of work + +on formalizing these +ideas of Landau getting + +some idea of what the ground +state does, is, and excitations + +that you can have +about the spectrum. + +And so he was very +happy at being + +able to explain this, +including the nature of rotons, + +et cetera. + +And he was worried +that somehow he + +couldn't get this +logarithmic divergence. + +And that bothered +him a little bit, + +but Onsager told him +that that's really + +a much more fundamental +property that + +depends on critical phenomena, +and for resolving that issue, + +you have to come to 8.334. + +So we will not discuss +that, nor will we + +discuss why this is Tc minus +T to the 2/3 power and not + +a linear dependence. + +It again is one of these +critical properties. + +But we should be able to +explain this T to the fourth. + +And clearly, this +T to the fourth + +is not as simple as saying this +exponent changed from 3/2 to 3, + +this 3/2 should +also change the 3. + +No, it went to T to the fourth, +so what's going on over here? + +So last time at the +end of the lecture + +I wrote a statement that +the BEC is not superfluid. + +And what that really +means is that it + +has too many excitations, +low energy excitations. + +So imagine the +following, that maybe we + +have a container-- I don't +know, maybe we have a tube-- + +and we have our superfluid going +through this with velocity v + +sub s. + +We want it to maintain that +velocity without experiencing + +friction, which it +seems to do in going + +through these capillaries. + +You don't have to push it, it +seems to be going by itself. + +And so the question is, +can any of these pictures + +that we drew for excitations +be consistent with this? + +Now, why am I talking about +excitations and consistency + +with superfluid? + +Because what can +happen in principle + +is that within your system, +you can spontaneously + +generate some excitation. + +This excitation will +have some momentum p + +and some energy epsilon of p. + +And if you spontaneously can +create these excitations that + +would take away energy from this +kinetic energy of the flowing + +superfluid, gradually the +superfluid will slow down. + +Its energy will be +dissipated and the superfluid + +itself will heat up +because you generated + +these excitations with it. + +So let's see what happens. + +If I were to create +such an excitation, + +actually I have to worry +about momentum conservation + +because I created something +that carried momentum p. + +Now initially, let's say +that this whole entity, all + +of the fluid that are +superflowing with velocity Vs + +have mass M. So the initial +momentum would be MVs. + +Now, I created some +excitation that + +is carrying away +some momentum p. + +So the only thing that +can ensure this happens + +is that I have to +slightly change + +the velocity of the fluid. + +Now this change in +velocity is infinitesimal. + +It is Vs minus p +divided by M. M is huge, + +so why bother +thinking about this? + +Well, let's see what +the change in energy is. + +Delta E. Let's say, well, +you created this excitation + +so you have energy epsilon of p. + +But I say, in +addition to that there + +is a change in the kinetic +energy of the superfluid. + +I'm now moving at +Vs prime squared, + +whereas initially when this +excitation was not present, + +I was moving at Vs. + +And so what do you have here? + +We have epsilon of p, M +over 2 Vs minus p over M, + +this infinitesimal change +in velocity squared minus M + +over 2 Vs squared. + +We can see that the leading +order of the kinetic energy + +goes away, but that there +is a cross term here + +in which the M contribution-- +the contribution of the mass-- + +goes away. + +And so the change in energy is +actually something like this. + +So if I had a system that +when stationary, the energy + +to create an excitation of +momentum p was epsilon of p, + +when I put that in a frame that +is moving with some velocity + +Vs, you have the +ability to borrow + +some of that kinetic energy +and the excitation energy + +goes down by this amount. + +So what happens if I take +the Bose-Einstein type + +of excitation spectrum +that is p squared over 2M + +and then subtract +a v dot p from it? + +Essentially there is a +linear subtraction going on, + +and I would get a +curve such as this. + +So I probably exaggerated +this by a lot. + +I shouldn't have +subtracted so much. + +Let me actually not +subject so much, + +because we don't want to go +all the way in that range. + +But you can see that there +is a range of momenta where + +you would spontaneously gain +energy by creating excitations. + +If the spectrum was +initially p squared over 2M, + +basically you just have too +many low energy excitations. + +As soon as you +start moving it, you + +will spontaneously +excite these things. + +Even if you were initially +at 0 temperature, + +these phonon excitations +would be created spontaneously + +in your system. + +They would move +all over the place. + +They would heat up your system. + +There is no way +that you can pass + +the Bose-Einstein +condensate-- actually, + +there's no way that you can even +move it without losing energy. + +But you can see that +this red curve does not + +have that difficulty. + +If I were to shift this curve +by an amount that is linear, + +what do I get? + +I will get something like this. + +So the Landau spectrum +is perfectly fine + +as far as excitations +is concerned. + +At zero temperature, even if the +whole fluid is moving then it + +cannot spontaneously +create excitations, + +because you would increase +energy of the system. + +So there's this difference. + +Ultimately, you would +say that the first time + +you would get excitation is +if you move it fast enough + +so that some portion of +this curve goes to 0. + +And indeed, if you were +to try to stir or move + +a superfluid fast +enough, there's + +a velocity at which +it breaks down, + +it stops being a superfluid. + +But it turns out that that +velocity is much, much smaller + +than you would predict based on +this roton spectrum going down. + +There are some other +many body excitations + +that come before and cause +the superfluid to lose energy + +and break down. + +But the genetic idea as +to why a linear spectrum + +for k close to 0 is +consist with superfluidity + +but the quadratic one +is not remains correct. + +Now suppose I am +in this situation. + +I have a moving super +fluid, such as the one + +that I have described over here. + +The spectrum is going to +be somewhat like this, + +but I'm not at 0 temperature. + +I want to try to describe +this T to the fourth behavior, + +so I want to be at some +finite temperature. + +So if I'm at some +finite temperature, + +there is some probability to +excite these different states, + +and the number that would +correspond to some momentum p + +would be given by this +general formula you have, + +1 over Z inverse e to the +beta epsilon of p minus 1. + +Furthermore, if I think that +I am in the regime where + +the number of excitations +is not important because + +of the same reason that I had +for Bose-Einstein condensate, + +I would have this formula +except that I would use epsilon + +of p that is appropriate +to this system. + +Actually, what is it +appropriate to this system + +is that my epsilon of +p was velocity times p. + +But then I started to move +with this superfluid velocity. + +Actually, maybe I'll +call this c so that I + +a distinction between c, which +is the linear spectrum here, + +and the superfluid +velocity dot p. + +No, this is actually +a vectorial product. + +And because of that, +I only drew one part + +of this curve that corresponds +to positive momentum. + +If I had gone to +negative momentum, + +actually, this curve +would have continued + +and whereas one branch +the energy is reduced, + +if I go to minus p, +the energy goes up. + +So whereas if the +superfluid was not moving, + +I can generate as many +excitations with momentum p + +as momentum minus p. + +Once the superfluid is +moving, there is a difference. + +One of them has a v dot p. + +The other has minus v dot p. + +So because of that, +there is a net momentum + +that is carried by +these excitations. + +This net momentum is +obtained by summing + +over all of these +things, multiplying + +with appropriate momentum. + +So I have beta is CP +minus v dot p minus 1. + +This is the momentum +of the excitation. + +This is the net momentum of +the system for one excitation. + +But then I have to sum +over all possible P's. + +Sum over P's, as +we've discussed, + +I can replace with an integral. + +And sum over k be replaced with +V. Integral over K, K and P + +are simply related +by a factor of h bar. + +So whereas before for k I +had 2 pi cubed for v cubed, + +I have 2 pi h bar cubed. + +So this is what I +have to calculate. + +Now what happens for small v? + +I can make an expansion +in vs. The 0 order term + +in the expansion +is what we would + +have for non-moving fluid. + +Momenta in the two +directions are the same, + +so that contribution goes away. + +The first contribution +that I'm going to get + +is going to come from expanding +this to lowest order in P. + +So there is a P that +is sitting out front. + +When I make the +expansion, I will + +get a vs dot P +times the derivative + +of the exponential +function gives me + +a factor of beta +e to the beta CP. + +And down here I will have e to +the beta CP minus 1 squared. + +Now, in the problem set you +have to actually evaluate + +this integral. + +It's not that difficult. + +It's related to Zeta functions. + +But what I'm really +only interested in what + +is the temperature dependence? + +You can see that I can rescale +this combination, call it x. + +Essentially what it says is that +whenever I see a factor of p, + +replace it by Kt over Cx. + +And how many P's do I have? + +I have three, four, five. + +So I have five factors of P. So +I will have five factors of Kt. + +One of them gets +killed by the beta, + +so this whole thing +is proportional to T + +to the fourth power. + +So what have we found? + +We have found that as +this fluid is moving + +at some finite +temperature T, it will + +generate these excitations. + +And these excitations +are preferably + +along the direction +of the momentum. + +And they correspond to +an additional momentum + +of the fluid that is +proportional to the volume. + +It's proportional to temperature +to the fourth and something. + +And of course, proportional +to the velocity. + +Now, we are used to thinking of +the proportionality of momentum + +and velocity to be +some kind of a mass. + +If I divide that +mass by the volume, + +I have a density of +these excitations. + +And what we have established +is that the density + +of those excitations +is proportional to t + +to the fourth. + +And what is happening in this +Andronikashvili experiment + +is that as these plates are +moving, by this mechanism + +the superfluid +that is in contact + +with them will +create excitations. + +And the momentum of +those excitations + +would correspond to some +kind of a density that + +vanishes as T to +the fourth, again + +in agreement with +what we've seen here. + +OK? + +Yes? + +AUDIENCE: So in an +integral expression + +you have vs as part +of a dot product. + +PROFESSOR: Yes. + +AUDIENCE: And then in the +next line [INAUDIBLE]. + +So it's in that direction. + +PROFESSOR: So let's give these +indices p in direction alpha. + +This is p in direction alpha. + +This is p in direction alpha. + +This is v in direction +beta, p in direction + +beta, sum over beta. + +Now, I have to do an +angular integration that + +is spherically symmetric. + +And then somewhere inside +there it has a p alpha p beta. + +That angular +integration will give me + +a p squared over three delta +alpha beta, which then converts + +this v beta to a +b alpha, which is + +in the direction +of the momentum. + +Yes? + +AUDIENCE: Will +you say once again + +what happened to the +integral dimension? + +PROFESSOR: OK. + +So when we are in the +Bose-Einstein condensate, + +as far as the +excitations of concerned + +we have zero chemical potential. + +Whatever number of +particle that we + +have in excess of what +can be accommodated + +through the excitations we put +together in the ground state. + +So if you like the ground +state, the kp equals to 0 + +or k equals to 0, +is a reservoir. + +You can add as many +particles there + +or bring as many particles +out of it as you like. + +So effectively, you have +no conservation number + +and no need for a [? z. ?] + +Of course, that we +only know for the case + +of the true +Bose-Einstein condensate. + +We are kind of +jumping and giving + +that concept relevance for +the interacting superfluid. + +OK? + +Any other questions? + +So this is actually +the last item + +I wanted to cover for +going on the board. + +The rest of the hour, +we have this movie + +that I had promised you. + +I will let that movie run. + +I also have all the connection +of problem sets, and exams, + +and test that you +have not picked up. + +So while the movie runs, you +are welcome to sit and enjoy it. + +It's very nice. + +Or you can go and take your +stuff and go your own way + +or do whatever you like. + +So let's go back. + +[VIDEO PLAYBACK] + +PROFESSOR: There +will be more action. + +-We just made a transfer +from liquid helium + +out of the storage tank into +our own experimental equipment. + +It is a remarkable [INAUDIBLE]. + +It has two different and +easily distinguishable + +liquid phases-- a +warmer and a colder one. + +The warmer phase is called +liquid helium I and the colder + +phase liquid helium II. + +The two stages are separated +by a transition temperature, + +known as the lambda point. + +When liquid helium is pulled +down through the lambda point, + +a transition from helium I to +helium II is clearly visible. + +We will show it to you +later in this film. + +The two liquids behave nothing +like any other known liquid, + +although it could be said that +helium I, the warmer phase, + +approximates the behavior +of common liquids. + +But it is helium II, +the colder phase, + +which is truly different. + +Because of this, it is +called a superfluid. + +The temperatures involved when +working with liquid helium + +are quite low. + +Helium boils at +4.2 degrees Kelvin + +under conditions of +atmospheric pressure. + +And the lambda point lies +at roughly 2.2 degrees. + +Note that this +corresponds to minus 269 + +and minus 271 +degrees centigrade. + +The properties of liquid +helium that I have just + +been telling you about +are characteristic + +of the heavy isotope +if helium, helium-4. + +The element occurs in the +form of two stable isotopes. + +[INAUDIBLE] The second +and lighter one, + +helium-3, is very rare. + +Its abundance is only +about 1 part of 10 million. + +Pure liquid helium-3 +is the subject + +of intensive study +at the present time, + +but so far no second +superfluid liquid phase + +has been found to +exist for helium-3. + +The low temperature at +which we'll be working + +calls for well-insulated +containers. + +The dewar meets +our requirements. + +The word "dewar" is +a scientific name + +given to a double-walled +vessel with the space + +between the walls evacuated. + +When these dewars +are made of glass, + +the surface of this +inner space is usually + +filtered to cut down heat +transfer by radiation. + +However, our dewars will +have to be transparent + +so that we can look at +what's going on inside. + +Now, liquid helium is commonly +stored in double dewars. + +The design is quite +simple, just put one + +inside the other like this. + +In the inner dewar, we +put the liquid helium, + +and in the space between +the inner and outer dewar, + +we maintain a supply +of liquid air. + +Here is a double dewar +exactly like the one + +we will be using in our +demonstration experiment. + +The inner dewar is filled +with liquid helium. + +The outer dewar +contains liquid air. + +The normal boiling +temperature of liquid air + +is about 80 degrees +Kelvin, 75 or more degrees + +hotter than liquid helium. + +The purpose of the +liquid air is twofold. + +First, we put the liquid air +in the outer dewar well ahead + +of putting liquid helium +in the inner dewar. + +In this way, the inner +dewar is pre-cooled. + +Secondly, we maintain +a supply of liquid air + +in the outer dewar +because it provides + +an additional +[INAUDIBLE] of insulation + +now that the liquid helium +is in the inner dewar. + +The [INAUDIBLE] liquid +air attests to the fact + +that it is absorbing +some of the heat which + +enters the double dewar. + +Even with the boiling +of the liquid air, + +the liquid helium +is clearly visible. + +Later, we will use +liquid air cooled + +below its boiling temperature +to reduce or eliminate + +the air bubbles for +better visibility. + +Now the liquid +air is cooled down + +and we have eliminated boiling. + +The smaller bubbles of +the boiling liquid helium + +are clearly visible. + +The cover over the inner dewar +has a port, at present open. + +The liquid helium is at +atmospheric pressure, + +so its temperature is +4.2 degrees Kelvin. + +In other words, what +we have in here now + +is liquid helium one, the +warmer of the two phases. + +Before we cool it down to take +a look at the superfluid phase, + +I want to dwell greatly on the +properties of helium I. I've + +told you before +that even helium I + +is different from +the normal liquids. + +The distance between neighboring +atoms and this liquid + +is quite large. + +The atoms are not +as closely packed + +as in the classical liquids. + +The reason for this +is quantum mechanics. + +The zero point energy is +relatively more important + +here than in any other liquid. + +As a consequence, +liquid helium has + +a very low mass density, only +about 13% the density of water, + +and a very low optical density. + +The index of refraction +is quite close to 1. + +This makes its surface hard +to see with the naked eye + +under ordinary +lighting conditions. + +You are no doubt +familiar with the fact + +that the helium atom has +closed shell atomic structure. + +This explains why helium is +a chemically inert element. + +It also accounts for the fact +that the force of attraction + +between neighboring helium +atoms, the so-called van der + +Waals force, is small. + +It takes little energy to +pull two helium atoms apart, + +as for example in evaporation. + +This gives liquid helium +a better small latent + +heat of vaporization. + +Only five calories are +needed to evaporate one gram. + +Compare this with water, +where evaporation requires + +between 500 and 600 +calories per gram. + +The low van der Waals force +combined with a large zero + +point energy also accounts for +the fact that liquid helium + +does not freeze, cannot +be solidified at ordinary + +pressure, no matter +how far we cool it. + +However, liquid helium has been +solidified at high pressure. + +The liquid helium in the +dewar is at 4,2 degrees. + +We now want to cool it +down to the lambda point + +and show you the transition +to the [INAUDIBLE]. + +Our method will be +cooling by evaporation + +using a vacuum pump. + +Now, the lambda point lies at +2.2 degrees, only 2 degrees + +colder than the [INAUDIBLE] +temperature of the liquid. + +What's more, not +very much heat has + +been removed from +the liquid helium + +now in the dewar to bring +it to the lambda point. + +It amounts to only +about 250 calories. + +Nevertheless, don't get the +idea that this cooling process + +is easy. + +On the contrary, +it's quite difficult. + +More than 1/3 of the liquid +helium now in the dewar + +has to be knocked +away in vapor form + +before we can get what remains +behind to the lambda point. + +That requires an +awful lot of pumping + +and explains why we use this +large and powerful vacuum + +pump over here. + +Even with this pump, +the cooling process + +takes a considerable +amount of time. + +Let me explain why +it is so difficult + +to cool liquid helium +to the lambda point. + +I have already mentioned +that liquid helium has + +a remarkably small +[INAUDIBLE] vaporization, + +only five calories per gram. + +At the same time, liquid +helium at 4.2 degrees + +has a high specific heat, +almost calorie per gram. + +Therefore, 1 gram of +the vapor pumped away + +carries with it +an amount of heat + +which can cool only 5 or 6 grams +of liquid helium by 1 degree. + +That's not very much cooling. + +It is less by a +factor of almost 100 + +than when we cool +water by evaporation. + +The situation gets even +worse as cooling progresses + +below 4.2 degrees because the +specific heat of liquid helium + +rises astonishingly. + +As we approach 2,17 +degrees, the lambda point. + +The heat of vaporization, +on the other hand, + +remains roughly the same. + +So a given amount +of vapor carried + +off produces less +and less cooling + +as we approach 2.17 degrees, + +Our thermometer here +is a low pressure gauge + +connected to the space +above the liquid helium. + +The needle registers +the pressure there. + +It is the saturated vapor +pressure of liquid helium. + +The gauge is calibrated for +the corresponding temperature. + +We call it a vapor +pressure thermometer. + +As we approach 2.17 +degrees, boiling + +becomes increasingly violent. + +Suddenly it stops. + +This was the transition. + +The liquid you now +see is helium II. + +Even though evaporation does +continue, there is no boiling. + +The normal liquids, such +as the water in this basin, + +boil because of their relatively +low heat conductivity. + +Before heat, +[INAUDIBLE] at one point + +can be carried away +to a cooler place + +in the liquid bubbles +of the vapor form. + +Helium I behaves like a +normal liquid in this respect. + +The absence of +boiling in helium II + +reveals that this +phase acts as if it + +had a large heat conductivity. + +As a matter of fact, as +the liquid helium passed + +through the lambda +point transition + +you just saw, its +heat conductivity + +increased by the fantastic +factor of one million. + +The heat conductivity of +helium II is many times + +greater than in the +metals silver and copper, + +which are among the best +solid heat conductors. + +And yet here we +deal with a liquid. + +For this alone, +helium II deserves + +the name of superfluid. + +Actually, the way in +which helium II transports + +such large quantities +of heat so rapidly + +is totally different from +the classical concept + +for heat conduction. + +I'll come back to +the subject later + +in connection with an +experiment demonstrating + +the phenomenon of second +sound in helium II. + +Remember that this great +change in heat conductivity + +occurred at a single +and fixed transition + +temperature, the lambda point. + +We do indeed deal with +a change in phase, + +only here it is a change from +one liquid to another liquid. + +As we told you before, the +specific heat of liquid helium + +is very large as a lambda point. + +In fact, it behaves abnormally +even below the lambda point + +and falls again very rapidly +with the temperature. + +This discontinuity +in specific heat + +is another reflection +of the fact + +that we are dealing +with a change + +in the phase of the substance. + +By the way, the curve resembles +the Greek letter lambda. + +The transition +temperature got its name + +from the shape of this curve. + +[INAUDIBLE] + +The next one has to do with +the viscosity of liquid helium. + +When a normal liquid +flows through a tube, + +it will resist the flow. + +In this experiment, we +shall cause some glycerin + +to flow to a tube +under its own weight. + +The top layer is +colored glycerin. + +The liquid layer closest to +the tube wall adheres to it. + +The layer next in from the one +touching the wall flows by it + +and is retarded as it flows due +to the interatomic, the van der + +Waals force of attraction. + +The second layer in +turn drags on the third, + +and so on inward from the +wall, producing fluid friction, + +or viscosity. + +The narrower the +tube, the slower + +the liquid rate +of flow through it + +under a given head of pressure. + +Here I have a beaker with +an unglazed ceramic bottom + +of ultra-fine [INAUDIBLE]. + +Many capillary channels run +through this ceramic disk. + +The diameter is quite small, +about one micron which is + +1/10,000 of a centimeter. + +There is liquid +helium in the beaker. + +It is 4.2 degrees Kelvin, +helium I, the normal phase. + +The capillaries in the +disk are fine enough + +to prevent the liquid now in +the beaker from flowing through + +under its on weight. + +Clearly, helium I is viscous. + +To be sure, its +viscosity is very small. + +That's why we had to choose +extremely fine capillaries + +to demonstrate it. + +Here you see the lambda +point transition. + +The helium II all poured out. + +The rate of pouring would +not be noticeably slower + +if the [INAUDIBLE] +were made yet finer. + +We call this kind +of flow a superflow. + +The temperature is +now at 1.6 degrees. + +The superflow is even faster. + +The viscosity of helium +II in this experiment + +is so small that it has +not been possible to find + +a value for it. + +It is less than the experimental +uncertainty incurred + +in attempts to measure it. + +We now believe that +helium II, the superfluid, + +has zero viscosity, although +we should be more precise here. + +We believe its viscosity is zero +when observing capillary flow. + +Bear this statement +in mind, for we + +will come up with a +contradiction to it + +in the next experiment, +where we will + +look for viscosity by +a different method. + +There is a copper cylinder +in the liquid helium, + +so mounted as we can turn +it about a vertical axis. + +In order to turn it smoothly +and with as little vibration as + +possible, we laid the +cylinder into the [INAUDIBLE] + +of a simple induction +motor energized + +from outside the dewar. + +The four horizontal +coils you see + +provide the torque which +turns the cylinder. + +The liquid helium is +electrically non-conducting. + +The coil exerts no +torque on it directly. + +Yet as we turn on our +motor, the liquid layer + +bounding the cylinder is +dragged along behind it. + +The boundary layer in turn +drags on the next layer, + +and so on outward. + +Finally a circulation +showing up in the helium + +due to its own viscosity and +the wooden panels we [INAUDIBLE] + +is turned along. + +What we have just seen +occurred in helium I, + +the normal phase at +4.2 degrees Kelvin. + +That is to say, +this demonstration + +is consistent with our results +for helium I by capillary flow. + +Helium I is viscous. + +Here you see the liquid +cooled down and passing + +into the superfluid +phase, helium II. + +Let's turn on the motor. + +The paddle wheel starts again. + +What does this mean? + +First of all, let me +emphasize that, like helium I, + +helium II is also non-conducting +in the electrical sense. + +In other words, the +circulation in the experiment + +can only have been caused +through viscous drag. + +So we conclude from the +rotating cylinder observations + +that helium II is viscous +and from the method + +of capillary flow that +it has zero viscosity. + +Our experimentation has +come up with a paradox. + +No normal classical +liquid is known + +to behave so inconsistently, in +capillary flow on the one hand + +and in bulk flow on the other. + +This state of affairs +forces us to think + +of helium II, the +superfluid, not as a single, + +but as a dual liquid. + +It appeared as if helium +II had two separate and yet + +interpenetrating +component liquids. + +We shall call one +component normal. + +It is this component +which we call + +responsible for the +appearance of viscosity + +below the lambda point in the +rotating cylinder experiment. + +The normal component, +as the name suggests, + +behaves like a normal liquid, +and therefore as viscosity. + +It is the one which the cylinder +drags along as its turned. + +But the normal components +cannot flow through the narrow + +channels of the ceramic disc +because of its viscosity. + +The second component +has zero viscosity, + +and it's called the +superfluid component. + +We think that it does +not participate at all + +in the rotating cylinder +experiment below the lambda + +point. + +It stays at rest. + +On the other hand, it can flow +through channels of one micron + +diameter with the greatest +of ease and countering + +no resistance whatever +because it has no viscosity. + +As we'll see later, this +flow is not repeated even + +when the capillary +diameters are made + +far smaller than one micron. + +This [INAUDIBLE] construction +is called the two fluid + +model for liquid helium II. + +Whether it is correct +or not depends + +on further tests +comparing the theory + +based on this model with +experimental results. + +We now go on to another +phenomenon, the fountain + +effect. + +What you see here +is a tube which + +narrows down and then +opens into a bulb. + +A small piece of cotton is +stuffed into the [INAUDIBLE] + +section between the +tube and the bulb. + +And the bulb has been tightly +packed with one of the finest + +powders available, [INAUDIBLE]. + +And second wad of cotton +keeps the powder in the bulb. + +This powder presents extremely +fine capillary channels. + +Their average diameter is a +small fraction of 1 micron. + +This device has been +placed in the dewar. + +The liquid helium is +below the lambda point. + +We submerge the bulb, and then +we'll send a beam of light + +from this lamp to a +point near the top. + +You will see the light beam +when the lamp is turned on. + +It focuses some heat in the +form of infrared radiation + +on the point in question. + +The temperature will rise +above the temperature + +of the rest of the apparatus. + +Let us turn it on. + +Liquid helium flows through the +hole in the bottom of the bulb, + +through the fine +powder, and rises + +above the level of +liquid helium outside. + +The height to which +it will go depends + +on the temperature +increase produced + +bu the lamp focused on the bulb. + +We can very well ask, where +does the mechanical energy + +come from that does the +work necessary to pump + +the liquid above +the ambient level? + +Before we attempt to +discuss this question, + +there are two other facts +that should be noted. + +The first is by now obvious. + +The upward flow through the bulb +must clearly be a superfluid. + +Only the superfluid component +of helium II could get through. + +The second fact is +more significant. + +Let me explain it this way, the +superfluid flows spontaneously + +from a to b,from a +cooler to a warmer place. + +Point a is in the +cold liquid, but b + +is being heated +with infrared rays. + +The second law of thermodynamics +positively says that heat + +cannot of itself flow from +a point of lower to a point + +of higher temperature. + +What does this mean +to us here, knowing + +as we do that the +superfluid is flowing + +from a colder to a warmer spot? + +Simply this, it carries no +heat, no thermal energy. + +Any internal energy +[INAUDIBLE] is no longer + +thermally available. + +To say it precisely, +it has zero entropy. + +We have discovered another +remarkable property + +of helium II. + +Its superfluid component +not only is friction free, + +it also contains no heat. + +The heat energy +contained in helium II + +as a whole resides, all of +it, in the normal component. + +We may, of course, add heat +to the superfluid component, + +as we are doing when it passes +the spot heated by the lamp. + +But in doing so, we +are converting it + +into the normal component. + +Let me return briefly to +a question posed earlier. + +Mechanical work is done +in pumping the liquid + +above equilibrium level. + +Where does it come from? + +I cannot answer this +question here in full, + +but it suffice to tell you that +we are dealing here with a heat + +engine. + +The mechanical energy +comes from the heat + +added at the light spot. + +An amusing demonstration +of the same phenomenon + +again uses a bulb +packed with rouge, + +but this one opens +into a capillary. + +Light is beamed on a spot +just below the capillary, + +and it produces a +helium fountain. + +The phenomenon in this and +the previous experiment + +has become known as +the thermomechanical, + +or the fountain, effect. + +Below the lambda point, +the superfluid component + +of liquid helium creeps +up along the walls + +of its container in an +extremely thin film. + +It is known as a Rollin film. + +This creeping film is +a variety of superflow. + +It is difficult to make the film +itself directly visible to you. + +To show it indirectly, +we've put some liquid helium + +into a glass vessel. + +It is below the lambda point. + +There is no part porous +bottom in this vessel. + +The film rises along +the inside wall + +and comes down +along the outside, + +collecting in drops +at the bottom. + +The thickness of +this creeping film + +is only a small fraction of +1 micron and of the order + +of 200 to 300 angstrom. + +Its speed, while small just +below the lambda point, + +may reach a value as +high as 35 centimeters + +per second at +lower temperatures. + +Our next experiment deals with +the phenomenon of second sound. + +We are all familiar with wave +motion in elastic materials, + +be they solids, +liquids, or gases. + +Elastic energy of deformation, +carried away from its source + +in the form of waves with +a characteristic speed, + +the speed of sound. + +Liquid helium is an +elastic substance + +both above and below +the lambda point. + +Both helium one and two +support sound waves. + +Now helium II, the +superfluid phase, + +also conducts heat +in the form of waves. + +This remarkable property is +shared by no other substance. + +For better or for worse, it +has been called second sound. + +Normal heat conduction +is a diffusion process. + +The rate of flow of heat is +proportional to the temperature + +differences. + +But in helium II it +is a wave process. + +Heat flows through helium II +with a characteristic speed, + +the speed of second sound. + +We shall send small heat pulses +into helium II from a heater. + +They will spread away +from the heater uniformly, + +carrying the heat +energy with them. + +The speed of second +sound is small just + +below the lambda point. + +In the neighborhood +of 1.6 degrees Kelvin, + +it reaches a value of +roughly 20 meters per second, + +and it is in this range that +we will run our demonstration. + +The experimental +procedure is as follows. + +There are two disks +in the liquid helium. + +They are carbon resistors +with the carbon applied + +in thin layers on one +side of each disk. + +In this way, good +thermal contact + +is established between the +resistor and the liquid helium. + +The following resistor +will be used as a heater. + +Electric currents will +be sent through it + +in pulses from this pulse +generator by means of the cable + +you see here. + +The [INAUDIBLE] of +the generator is also + +connected via a second cable +to a dual-trace oscilloscope, + +where it will be recorded +on the bottom [? trip. ?] + +In other words, it will record +the heat pulse as it enters + +the liquid helium. + +The pulses have been turned on. + +They themselves trigger +the horizontal sweep + +of [INAUDIBLE], which +records [INAUDIBLE]. + +It is calibrated +at 1 millisecond + +per unit on the scale. + +The pulses are 1 +millisecond long. + +The pulses leave the +heater at the bottom + +in the form of +second sound and move + +up to where they strike the +carbon resistor at the top. + +Being heat pulses, they +greatly raise is temperature. + +The carbon resistor is +quite sensitive to changes + +in temperature. + +It acts as a thermometer. + +So the heat pulse +of second sound + +creates a pulse-like +change in the resistance + +of the [INAUDIBLE] up here. + +It isn't hard to +convert this resistance + +pulse into a [INAUDIBLE]. + +What we will do is to +maintain a small DC + +current in the top resistor. + +It is supplied from a +battery in this metal box. + +The box shields the +circuits in order + +to reduce electronic noise. + +The voltage pulse is small. + +In this second box +we have an amplifier. + +The amplified output is fed +into the oscilloscope, where + +it will appear on +the upper trace. + +The horizontal +timescale on this trace + +is exactly the same as +for the bottom trace. + +However, the upper trace +records both exchanges + +as they occur in +the top resistor, + +a detector of second sound. + +The temperature of the liquid +is about 1.65 degrees Kelvin. + +The battery has been turned +on, and now the amplifier. + +Among noise and other +distortions in the upper trace, + +a clear-cut voltage pulse +appears about 4 and 1/2 units + +to the right, 4 and +1/2 milliseconds later + +than the pulse +entering the heater. + +This pulse in the upper trace is +also about 1 millisecond long. + +It is the second sound as it +arrives at the upper resistor. + +The upper trace also shows +a strong voltage pulse + +at the left, simultaneous +to the heater pulse. + +That's due to pick-up +by electromagnetic waves + +with the heater acting as +transmitter and the detector + +as receiver. + +We're moving the detector +toward the heater. + +The pulse moves +with it to the left. + +Notice the echos of second sound +which appear on the upper trace + +while the detector +is near the heater. + +They're caused by multiple +reflections between the two + +resistors. + +A total of three echos +is clearly visible. + +[END VIDEO PLAYBACK] + +PROFESSOR: OK, you can watch +the rest of it at home. \ No newline at end of file diff --git a/6swIAqXcvDQ.txt b/6swIAqXcvDQ.txt new file mode 100644 index 0000000000000000000000000000000000000000..5d15000cc828310e8ec0cf29ba045a32a2f60a06 --- /dev/null +++ b/6swIAqXcvDQ.txt @@ -0,0 +1,14619 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT OpenCourseWare continue to + + align:start position:0% +will help MIT OpenCourseWare continue to + + + align:start position:0% +will help MIT OpenCourseWare continue to +offer high quality educational resources + + align:start position:0% +offer high quality educational resources + + + align:start position:0% +offer high quality educational resources +for free + + align:start position:0% +for free + + + align:start position:0% +for free +to make a donation or to view additional + + align:start position:0% +to make a donation or to view additional + + + align:start position:0% +to make a donation or to view additional +materials from hundreds of MIT courses + + align:start position:0% +materials from hundreds of MIT courses + + + align:start position:0% +materials from hundreds of MIT courses +visit MIT opencourseware at ocw.mit.edu + + align:start position:0% + + + + align:start position:0% + +probably the time has begun to begin + + align:start position:0% +probably the time has begun to begin + + + align:start position:0% +probably the time has begun to begin +welcome I've given a guest lecture in + + align:start position:0% +welcome I've given a guest lecture in + + + align:start position:0% +welcome I've given a guest lecture in +this class for a few years running now + + align:start position:0% +this class for a few years running now + + + align:start position:0% +this class for a few years running now +and so I'm always happy to return you're + + align:start position:0% +and so I'm always happy to return you're + + + align:start position:0% +and so I'm always happy to return you're +working on a good subject here I'm going + + align:start position:0% +working on a good subject here I'm going + + + align:start position:0% +working on a good subject here I'm going +to talk today about experimentation and + + align:start position:0% +to talk today about experimentation and + + + align:start position:0% +to talk today about experimentation and +robust design of engineering systems I + + align:start position:0% +robust design of engineering systems I + + + align:start position:0% +robust design of engineering systems I +think you've already had a few lectures + + align:start position:0% +think you've already had a few lectures + + + align:start position:0% +think you've already had a few lectures +on design of experiments formally so + + align:start position:0% +on design of experiments formally so + + + align:start position:0% +on design of experiments formally so +this will build on that the figure that + + align:start position:0% +this will build on that the figure that + + + align:start position:0% +this will build on that the figure that +I show on this first slide concerns on + + align:start position:0% +I show on this first slide concerns on + + + align:start position:0% +I show on this first slide concerns on +the right a method by which one can make + + align:start position:0% +the right a method by which one can make + + + align:start position:0% +the right a method by which one can make +improvements and robustness of a system + + align:start position:0% +improvements and robustness of a system + + + align:start position:0% +improvements and robustness of a system +by adaptively experimenting in the + + align:start position:0% +by adaptively experimenting in the + + + align:start position:0% +by adaptively experimenting in the +parameter space of that system and the + + align:start position:0% +parameter space of that system and the + + + align:start position:0% +parameter space of that system and the +figure on the left is meant to indicate + + align:start position:0% +figure on the left is meant to indicate + + + align:start position:0% +figure on the left is meant to indicate +why that approach has worked rather + + align:start position:0% +why that approach has worked rather + + + align:start position:0% +why that approach has worked rather +quite a lot better than people expected + + align:start position:0% +quite a lot better than people expected + + + align:start position:0% +quite a lot better than people expected +and I'll be going into that in some + + align:start position:0% +and I'll be going into that in some + + + align:start position:0% +and I'll be going into that in some +detail and I hope that as I go through + + align:start position:0% +detail and I hope that as I go through + + + align:start position:0% +detail and I hope that as I go through +all this you'll take time to ask + + align:start position:0% +all this you'll take time to ask + + + align:start position:0% +all this you'll take time to ask +questions because I think that's better + + align:start position:0% +questions because I think that's better + + + align:start position:0% +questions because I think that's better +for you and more interesting for me too + + align:start position:0% +for you and more interesting for me too + + + align:start position:0% +for you and more interesting for me too +so just to give you a little bit of + + align:start position:0% +so just to give you a little bit of + + + align:start position:0% +so just to give you a little bit of +context you know this this topic of a + + align:start position:0% +context you know this this topic of a + + + align:start position:0% +context you know this this topic of a +depth of experimentation and robust + + align:start position:0% +depth of experimentation and robust + + + align:start position:0% +depth of experimentation and robust +design is really central to my research + + align:start position:0% +design is really central to my research + + + align:start position:0% +design is really central to my research +it's I think the core of it but I'm + + align:start position:0% +it's I think the core of it but I'm + + + align:start position:0% +it's I think the core of it but I'm +interested in other things as well such + + align:start position:0% +interested in other things as well such + + + align:start position:0% +interested in other things as well such +as we do studies of systems generally + + align:start position:0% +as we do studies of systems generally + + + align:start position:0% +as we do studies of systems generally +and the regularities that exist in those + + align:start position:0% +and the regularities that exist in those + + + align:start position:0% +and the regularities that exist in those +engineered systems and that gives rise + + align:start position:0% +engineered systems and that gives rise + + + align:start position:0% +engineered systems and that gives rise +to data that we can use more generally + + align:start position:0% +to data that we can use more generally + + + align:start position:0% +to data that we can use more generally +in methodology validation so we can look + + align:start position:0% +in methodology validation so we can look + + + align:start position:0% +in methodology validation so we can look +at different ways that people will do + + align:start position:0% +at different ways that people will do + + + align:start position:0% +at different ways that people will do +engineering and try to assess its + + align:start position:0% +engineering and try to assess its + + + align:start position:0% +engineering and try to assess its +effectiveness and of course all this is + + align:start position:0% +effectiveness and of course all this is + + + align:start position:0% +effectiveness and of course all this is +linked in with the work on adaptive + + align:start position:0% +linked in with the work on adaptive + + + align:start position:0% +linked in with the work on adaptive +experimentation because we need a way to + + align:start position:0% +experimentation because we need a way to + + + align:start position:0% +experimentation because we need a way to +validate our work but the the main topic + + align:start position:0% +validate our work but the the main topic + + + align:start position:0% +validate our work but the the main topic +today will be what was in the middle of + + align:start position:0% +today will be what was in the middle of + + + align:start position:0% +today will be what was in the middle of +that slide that's adaptive + + align:start position:0% +that slide that's adaptive + + + align:start position:0% +that slide that's adaptive +experimentation I think I'll start with + + align:start position:0% +experimentation I think I'll start with + + + align:start position:0% +experimentation I think I'll start with +some history and use that to explain the + + align:start position:0% +some history and use that to explain the + + + align:start position:0% +some history and use that to explain the +motivation you know why is it that we're + + align:start position:0% +motivation you know why is it that we're + + + align:start position:0% +motivation you know why is it that we're +addressing this topic why are we + + align:start position:0% +addressing this topic why are we + + + align:start position:0% +addressing this topic why are we +addressing + + align:start position:0% +addressing + + + align:start position:0% +addressing +the way we're addressing it and then I'm + + align:start position:0% +the way we're addressing it and then I'm + + + align:start position:0% +the way we're addressing it and then I'm +going to show you the research itself on + + align:start position:0% +going to show you the research itself on + + + align:start position:0% +going to show you the research itself on +adaptive experimentation robust design + + align:start position:0% +adaptive experimentation robust design + + + align:start position:0% +adaptive experimentation robust design +so I start with this quote from Sir + + align:start position:0% +so I start with this quote from Sir + + + align:start position:0% +so I start with this quote from Sir +Edward John Russell now this fellow was + + align:start position:0% +Edward John Russell now this fellow was + + + align:start position:0% +Edward John Russell now this fellow was +prominent in his day you know he was + + align:start position:0% +prominent in his day you know he was + + + align:start position:0% +prominent in his day you know he was +knighted that's why it says Sir Edward + + align:start position:0% +knighted that's why it says Sir Edward + + + align:start position:0% +knighted that's why it says Sir Edward +John Russell there under his type under + + align:start position:0% +John Russell there under his type under + + + align:start position:0% +John Russell there under his type under +his picture and as late as 1926 he was + + align:start position:0% +his picture and as late as 1926 he was + + + align:start position:0% +his picture and as late as 1926 he was +still expressing a view about how to do + + align:start position:0% +still expressing a view about how to do + + + align:start position:0% +still expressing a view about how to do +experimentation he said that you should + + align:start position:0% +experimentation he said that you should + + + align:start position:0% +experimentation he said that you should +seek simplicity in the way that you + + align:start position:0% +seek simplicity in the way that you + + + align:start position:0% +seek simplicity in the way that you +conduct your experiments and maybe you + + align:start position:0% +conduct your experiments and maybe you + + + align:start position:0% +conduct your experiments and maybe you +should ask just a few questions at a + + align:start position:0% +should ask just a few questions at a + + + align:start position:0% +should ask just a few questions at a +time or maybe even just one question at + + align:start position:0% +time or maybe even just one question at + + + align:start position:0% +time or maybe even just one question at +a time as you're conducting your + + align:start position:0% +a time as you're conducting your + + + align:start position:0% +a time as you're conducting your +experiments and this was a prominent + + align:start position:0% +experiments and this was a prominent + + + align:start position:0% +experiments and this was a prominent +view in that day generally accepted and + + align:start position:0% +view in that day generally accepted and + + + align:start position:0% +view in that day generally accepted and +and you can trace it back at least as + + align:start position:0% +and you can trace it back at least as + + + align:start position:0% +and you can trace it back at least as +far as Francis Bacon and maybe farther + + align:start position:0% +far as Francis Bacon and maybe farther + + + align:start position:0% +far as Francis Bacon and maybe farther +and what's interesting about this is + + align:start position:0% +and what's interesting about this is + + + align:start position:0% +and what's interesting about this is +just at the time he's still expressing + + align:start position:0% +just at the time he's still expressing + + + align:start position:0% +just at the time he's still expressing +his views about how it is that they + + align:start position:0% +his views about how it is that they + + + align:start position:0% +his views about how it is that they +conducted experiments there at + + align:start position:0% +conducted experiments there at + + + align:start position:0% +conducted experiments there at +Rothamsted he hired another person our a + + align:start position:0% +Rothamsted he hired another person our a + + + align:start position:0% +Rothamsted he hired another person our a +fishery now I should say that this is an + + align:start position:0% +fishery now I should say that this is an + + + align:start position:0% +fishery now I should say that this is an +interesting confluence you have two men + + align:start position:0% +interesting confluence you have two men + + + align:start position:0% +interesting confluence you have two men +very prominent very successful coming + + align:start position:0% +very prominent very successful coming + + + align:start position:0% +very prominent very successful coming +together in the same place at the same + + align:start position:0% +together in the same place at the same + + + align:start position:0% +together in the same place at the same +time I think the reason for that was + + align:start position:0% +time I think the reason for that was + + + align:start position:0% +time I think the reason for that was +that this experimental station + + align:start position:0% +that this experimental station + + + align:start position:0% +that this experimental station +Rothamsted was addressing I think one of + + align:start position:0% +Rothamsted was addressing I think one of + + + align:start position:0% +Rothamsted was addressing I think one of +the great problems of their time which + + align:start position:0% +the great problems of their time which + + + align:start position:0% +the great problems of their time which +was consistency and efficiency of + + align:start position:0% +was consistency and efficiency of + + + align:start position:0% +was consistency and efficiency of +agricultural production if you think + + align:start position:0% +agricultural production if you think + + + align:start position:0% +agricultural production if you think +about the middle of the 19th century the + + align:start position:0% +about the middle of the 19th century the + + + align:start position:0% +about the middle of the 19th century the +UK and other parts of the world + + align:start position:0% +UK and other parts of the world + + + align:start position:0% +UK and other parts of the world +experienced a terrible famines and so + + align:start position:0% +experienced a terrible famines and so + + + align:start position:0% +experienced a terrible famines and so +trying to do much better in this area + + align:start position:0% +trying to do much better in this area + + + align:start position:0% +trying to do much better in this area +was a pressing problem probably + + align:start position:0% +was a pressing problem probably + + + align:start position:0% +was a pressing problem probably +equivalent today to the way we feel + + align:start position:0% +equivalent today to the way we feel + + + align:start position:0% +equivalent today to the way we feel +about energy supply or global warming + + align:start position:0% +about energy supply or global warming + + + align:start position:0% +about energy supply or global warming +and now in some ways we take for granted + + align:start position:0% +and now in some ways we take for granted + + + align:start position:0% +and now in some ways we take for granted +food supply at least in the developed + + align:start position:0% +food supply at least in the developed + + + align:start position:0% +food supply at least in the developed +world so here we have this confluence + + align:start position:0% +world so here we have this confluence + + + align:start position:0% +world so here we have this confluence +and are a Fisher comes into the lab and + + align:start position:0% +and are a Fisher comes into the lab and + + + align:start position:0% +and are a Fisher comes into the lab and +he has a very different view about how + + align:start position:0% +he has a very different view about how + + + align:start position:0% +he has a very different view about how +to do experimentation + + align:start position:0% +to do experimentation + + + align:start position:0% +to do experimentation +he analyzes this experiment in which we + + align:start position:0% +he analyzes this experiment in which we + + + align:start position:0% +he analyzes this experiment in which we +see the table three in the middle this + + align:start position:0% +see the table three in the middle this + + + align:start position:0% +see the table three in the middle this +is from RI Fisher's 1921 paper and what + + align:start position:0% +is from RI Fisher's 1921 paper and what + + + align:start position:0% +is from RI Fisher's 1921 paper and what +you see is a plot with different levels + + align:start position:0% +you see is a plot with different levels + + + align:start position:0% +you see is a plot with different levels +of ammonia being applied as fertilizer + + align:start position:0% +of ammonia being applied as fertilizer + + + align:start position:0% +of ammonia being applied as fertilizer +to the fields and you see the influence + + align:start position:0% +to the fields and you see the influence + + + align:start position:0% +to the fields and you see the influence +on the yield per acre of oats and the + + align:start position:0% +on the yield per acre of oats and the + + + align:start position:0% +on the yield per acre of oats and the +decrement in each year because when you + + align:start position:0% +decrement in each year because when you + + + align:start position:0% +decrement in each year because when you +apply the fertilizer to the same field + + align:start position:0% +apply the fertilizer to the same field + + + align:start position:0% +apply the fertilizer to the same field +year after year the its effects diminish + + align:start position:0% +year after year the its effects diminish + + + align:start position:0% +year after year the its effects diminish +over time and apparently Fischer was + + align:start position:0% +over time and apparently Fischer was + + + align:start position:0% +over time and apparently Fischer was +fairly discouraged by this experiment + + align:start position:0% +fairly discouraged by this experiment + + + align:start position:0% +fairly discouraged by this experiment +when you read the paper you you see the + + align:start position:0% +when you read the paper you you see the + + + align:start position:0% +when you read the paper you you see the +details and you see the difficulties + + align:start position:0% +details and you see the difficulties + + + align:start position:0% +details and you see the difficulties +they experienced in analyzing the data + + align:start position:0% +they experienced in analyzing the data + + + align:start position:0% +they experienced in analyzing the data +you know they had some pests intruding + + align:start position:0% +you know they had some pests intruding + + + align:start position:0% +you know they had some pests intruding +on parts of the land and this made it + + align:start position:0% +on parts of the land and this made it + + + align:start position:0% +on parts of the land and this made it +complex to draw inferences from the + + align:start position:0% +complex to draw inferences from the + + + align:start position:0% +complex to draw inferences from the +experiment and he was later quoted to + + align:start position:0% +experiment and he was later quoted to + + + align:start position:0% +experiment and he was later quoted to +say the following thing which expressed + + align:start position:0% +say the following thing which expressed + + + align:start position:0% +say the following thing which expressed +that frustration in a way you have a + + align:start position:0% +that frustration in a way you have a + + + align:start position:0% +that frustration in a way you have a +bunch of scientists plan an experiment + + align:start position:0% +bunch of scientists plan an experiment + + + align:start position:0% +bunch of scientists plan an experiment +based on their knowledge of what to do + + align:start position:0% +based on their knowledge of what to do + + + align:start position:0% +based on their knowledge of what to do +later in you call statisticians in to + + align:start position:0% +later in you call statisticians in to + + + align:start position:0% +later in you call statisticians in to +analyze the data and to get the most + + align:start position:0% +analyze the data and to get the most + + + align:start position:0% +analyze the data and to get the most +precise inferences you can and oppressor + + align:start position:0% +precise inferences you can and oppressor + + + align:start position:0% +precise inferences you can and oppressor +precise estimates and it's really too + + align:start position:0% +precise estimates and it's really too + + + align:start position:0% +precise estimates and it's really too +late the tylium for statistical thinking + + align:start position:0% +late the tylium for statistical thinking + + + align:start position:0% +late the tylium for statistical thinking +is before you actually run the + + align:start position:0% +is before you actually run the + + + align:start position:0% +is before you actually run the +experiment that's when you can get the + + align:start position:0% +experiment that's when you can get the + + + align:start position:0% +experiment that's when you can get the +greatest benefits and what he talked + + align:start position:0% +greatest benefits and what he talked + + + align:start position:0% +greatest benefits and what he talked +about is the idea that the most finesse + + align:start position:0% +about is the idea that the most finesse + + + align:start position:0% +about is the idea that the most finesse +you could apply might improve your + + align:start position:0% +you could apply might improve your + + + align:start position:0% +you could apply might improve your +analysis of the data by a few percent + + align:start position:0% +analysis of the data by a few percent + + + align:start position:0% +analysis of the data by a few percent +one way or other but if you brought in + + align:start position:0% +one way or other but if you brought in + + + align:start position:0% +one way or other but if you brought in +the experimenter earlier maybe you'd get + + align:start position:0% +the experimenter earlier maybe you'd get + + + align:start position:0% +the experimenter earlier maybe you'd get +a factor of two or five in efficiency + + align:start position:0% +a factor of two or five in efficiency + + + align:start position:0% +a factor of two or five in efficiency +and accuracy and you can see how + + align:start position:0% +and accuracy and you can see how + + + align:start position:0% +and accuracy and you can see how +thoughtful Fischer was you know you see + + align:start position:0% +thoughtful Fischer was you know you see + + + align:start position:0% +thoughtful Fischer was you know you see +he seems to be struggling a hard to + + align:start position:0% +he seems to be struggling a hard to + + + align:start position:0% +he seems to be struggling a hard to +think there and I think part of it is + + align:start position:0% +think there and I think part of it is + + + align:start position:0% +think there and I think part of it is +that machine that's in front of them + + align:start position:0% +that machine that's in front of them + + + align:start position:0% +that machine that's in front of them +which is I guess what you'd use for a + + align:start position:0% +which is I guess what you'd use for a + + + align:start position:0% +which is I guess what you'd use for a +computer in that day I guess it's some + + align:start position:0% +computer in that day I guess it's some + + + align:start position:0% +computer in that day I guess it's some +sort of mechanical adding device I think + + align:start position:0% +sort of mechanical adding device I think + + + align:start position:0% +sort of mechanical adding device I think +it's it's nice that we have + + align:start position:0% +it's it's nice that we have + + + align:start position:0% +it's it's nice that we have +much better machines now for this + + align:start position:0% +much better machines now for this + + + align:start position:0% +much better machines now for this +purpose in fact what we find is that you + + align:start position:0% +purpose in fact what we find is that you + + + align:start position:0% +purpose in fact what we find is that you +can do a lot with statistics these days + + align:start position:0% +can do a lot with statistics these days + + + align:start position:0% +can do a lot with statistics these days +by knowing how to work with computers + + align:start position:0% +by knowing how to work with computers + + + align:start position:0% +by knowing how to work with computers +right and in fact a lot of the research + + align:start position:0% +right and in fact a lot of the research + + + align:start position:0% +right and in fact a lot of the research +results I'll show you today we wouldn't + + align:start position:0% +results I'll show you today we wouldn't + + + align:start position:0% +results I'll show you today we wouldn't +be able to achieve them with without + + align:start position:0% +be able to achieve them with without + + + align:start position:0% +be able to achieve them with without +modern digital computers so Fisher + + align:start position:0% +modern digital computers so Fisher + + + align:start position:0% +modern digital computers so Fisher +begins to plant experiments in a + + align:start position:0% +begins to plant experiments in a + + + align:start position:0% +begins to plant experiments in a +different way and this is one of the + + align:start position:0% +different way and this is one of the + + + align:start position:0% +different way and this is one of the +first ones that in the literature this + + align:start position:0% +first ones that in the literature this + + + align:start position:0% +first ones that in the literature this +figure figure one from his 1926 paper on + + align:start position:0% +figure figure one from his 1926 paper on + + + align:start position:0% +figure figure one from his 1926 paper on +the arrangement of field experiments and + + align:start position:0% +the arrangement of field experiments and + + + align:start position:0% +the arrangement of field experiments and +if you've done some work already in this + + align:start position:0% +if you've done some work already in this + + + align:start position:0% +if you've done some work already in this +course on design of experiments you + + align:start position:0% +course on design of experiments you + + + align:start position:0% +course on design of experiments you +might recognize this + + align:start position:0% +might recognize this + + + align:start position:0% +might recognize this +you see somewhat indicated by darker + + align:start position:0% +you see somewhat indicated by darker + + + align:start position:0% +you see somewhat indicated by darker +lines that there are eight different + + align:start position:0% +lines that there are eight different + + + align:start position:0% +lines that there are eight different +subplots in this plot and if I focus my + + align:start position:0% +subplots in this plot and if I focus my + + + align:start position:0% +subplots in this plot and if I focus my +attention on just say the upper left + + align:start position:0% +attention on just say the upper left + + + align:start position:0% +attention on just say the upper left +what I see is and I think the people + + align:start position:0% +what I see is and I think the people + + + align:start position:0% +what I see is and I think the people +even remotely can see the arrow right + + align:start position:0% +even remotely can see the arrow right + + + align:start position:0% +even remotely can see the arrow right +you see the plot has three different + + align:start position:0% +you see the plot has three different + + + align:start position:0% +you see the plot has three different +indications in each plot in this case + + align:start position:0% +indications in each plot in this case + + + align:start position:0% +indications in each plot in this case +it's two and M and early and the next + + align:start position:0% +it's two and M and early and the next + + + align:start position:0% +it's two and M and early and the next +one it's two and s and late so the two + + align:start position:0% +one it's two and s and late so the two + + + align:start position:0% +one it's two and s and late so the two +and the one indicate an amount of a + + align:start position:0% +and the one indicate an amount of a + + + align:start position:0% +and the one indicate an amount of a +fertilizer that's been applied s and M + + align:start position:0% +fertilizer that's been applied s and M + + + align:start position:0% +fertilizer that's been applied s and M +indicate the type of the fertilizer and + + align:start position:0% +indicate the type of the fertilizer and + + + align:start position:0% +indicate the type of the fertilizer and +early in late describe the time in the + + align:start position:0% +early in late describe the time in the + + + align:start position:0% +early in late describe the time in the +season the planting season when it's + + align:start position:0% +season the planting season when it's + + + align:start position:0% +season the planting season when it's +applied and we see in this first block + + align:start position:0% +applied and we see in this first block + + + align:start position:0% +applied and we see in this first block +we have four of the twos and four of the + + align:start position:0% +we have four of the twos and four of the + + + align:start position:0% +we have four of the twos and four of the +ones and four of the Early's and four of + + align:start position:0% +ones and four of the Early's and four of + + + align:start position:0% +ones and four of the Early's and four of +the lates and so on and we even see that + + align:start position:0% +the lates and so on and we even see that + + + align:start position:0% +the lates and so on and we even see that +there is a balance in the sense that + + align:start position:0% +there is a balance in the sense that + + + align:start position:0% +there is a balance in the sense that +there are two of the two M's and two of + + align:start position:0% +there are two of the two M's and two of + + + align:start position:0% +there are two of the two M's and two of +the two S's so pairwise there's a + + align:start position:0% +the two S's so pairwise there's a + + + align:start position:0% +the two S's so pairwise there's a +balance and so on and you may recognize + + align:start position:0% +balance and so on and you may recognize + + + align:start position:0% +balance and so on and you may recognize +that if I just focus on two and M and + + align:start position:0% +that if I just focus on two and M and + + + align:start position:0% +that if I just focus on two and M and +early in late and there are eight of + + align:start position:0% +early in late and there are eight of + + + align:start position:0% +early in late and there are eight of +such blocks in here we have every + + align:start position:0% +such blocks in here we have every + + + align:start position:0% +such blocks in here we have every +permutation and combination of the + + align:start position:0% +permutation and combination of the + + + align:start position:0% +permutation and combination of the +factors in the level so I would say you + + align:start position:0% +factors in the level so I would say you + + + align:start position:0% +factors in the level so I would say you +could describe this as a + + align:start position:0% +could describe this as a + + + align:start position:0% +could describe this as a +two to three full factorial experiment + + align:start position:0% +two to three full factorial experiment + + + align:start position:0% +two to three full factorial experiment +within the block which is eight now you + + align:start position:0% +within the block which is eight now you + + + align:start position:0% +within the block which is eight now you +you might also say that it's a three + + align:start position:0% +you might also say that it's a three + + + align:start position:0% +you might also say that it's a three +raised to the one and and two raised to + + align:start position:0% +raised to the one and and two raised to + + + align:start position:0% +raised to the one and and two raised to +the two because there are also these + + align:start position:0% +the two because there are also these + + + align:start position:0% +the two because there are also these +four plots in which there are just X's + + align:start position:0% +four plots in which there are just X's + + + align:start position:0% +four plots in which there are just X's +and no fertilizers applied you could + + align:start position:0% +and no fertilizers applied you could + + + align:start position:0% +and no fertilizers applied you could +call that a control or you could say + + align:start position:0% +call that a control or you could say + + + align:start position:0% +call that a control or you could say +that this is actually a more complex + + align:start position:0% +that this is actually a more complex + + + align:start position:0% +that this is actually a more complex +factorial experiment where in one of the + + align:start position:0% +factorial experiment where in one of the + + + align:start position:0% +factorial experiment where in one of the +levels sort of obviates the other two + + align:start position:0% +levels sort of obviates the other two + + + align:start position:0% +levels sort of obviates the other two +and once you decide to apply no + + align:start position:0% +and once you decide to apply no + + + align:start position:0% +and once you decide to apply no +fertilizer it doesn't matter whether you + + align:start position:0% +fertilizer it doesn't matter whether you + + + align:start position:0% +fertilizer it doesn't matter whether you +apply type 1 or type 2 or quiet earlier + + align:start position:0% +apply type 1 or type 2 or quiet earlier + + + align:start position:0% +apply type 1 or type 2 or quiet earlier +late and then to further complicate the + + align:start position:0% +late and then to further complicate the + + + align:start position:0% +late and then to further complicate the +issue we have eight plots and within + + align:start position:0% +issue we have eight plots and within + + + align:start position:0% +issue we have eight plots and within +those blocks those subplots we have + + align:start position:0% +those blocks those subplots we have + + + align:start position:0% +those blocks those subplots we have +randomization in space of the different + + align:start position:0% +randomization in space of the different + + + align:start position:0% +randomization in space of the different +treatments and one of the things that + + align:start position:0% +treatments and one of the things that + + + align:start position:0% +treatments and one of the things that +Fischer talks about here is how poorly + + align:start position:0% +Fischer talks about here is how poorly + + + align:start position:0% +Fischer talks about here is how poorly +randomization actually works sometimes + + align:start position:0% +randomization actually works sometimes + + + align:start position:0% +randomization actually works sometimes +so if I look down on this plot it's on + + align:start position:0% +so if I look down on this plot it's on + + + align:start position:0% +so if I look down on this plot it's on +the lower right this this plot is + + align:start position:0% +the lower right this this plot is + + + align:start position:0% +the lower right this this plot is +randomized in spatial distribution of + + align:start position:0% +randomized in spatial distribution of + + + align:start position:0% +randomized in spatial distribution of +the treatments but you see that all of + + align:start position:0% +the treatments but you see that all of + + + align:start position:0% +the treatments but you see that all of +the left-hand plots are early and all of + + align:start position:0% +the left-hand plots are early and all of + + + align:start position:0% +the left-hand plots are early and all of +the right-hand plots are late so + + align:start position:0% +the right-hand plots are late so + + + align:start position:0% +the right-hand plots are late so +sometimes randomization gives you such + + align:start position:0% +sometimes randomization gives you such + + + align:start position:0% +sometimes randomization gives you such +such problems in fact these days often + + align:start position:0% +such problems in fact these days often + + + align:start position:0% +such problems in fact these days often +people will not use randomization and + + align:start position:0% +people will not use randomization and + + + align:start position:0% +people will not use randomization and +instead use something like a Latin + + align:start position:0% +instead use something like a Latin + + + align:start position:0% +instead use something like a Latin +hypercube design - rather than + + align:start position:0% +hypercube design - rather than + + + align:start position:0% +hypercube design - rather than +randomization but this was one of the + + align:start position:0% +randomization but this was one of the + + + align:start position:0% +randomization but this was one of the +early experiments that had been + + align:start position:0% +early experiments that had been + + + align:start position:0% +early experiments that had been +considered in a factorial design and I + + align:start position:0% +considered in a factorial design and I + + + align:start position:0% +considered in a factorial design and I +think it's interesting that Fischer + + align:start position:0% +think it's interesting that Fischer + + + align:start position:0% +think it's interesting that Fischer +decided to call it a complex experiment + + align:start position:0% +decided to call it a complex experiment + + + align:start position:0% +decided to call it a complex experiment +it's as if he was trying to emphasize as + + align:start position:0% +it's as if he was trying to emphasize as + + + align:start position:0% +it's as if he was trying to emphasize as +strongly as possible his difference of + + align:start position:0% +strongly as possible his difference of + + + align:start position:0% +strongly as possible his difference of +opinion with Russell his boss who had + + align:start position:0% +opinion with Russell his boss who had + + + align:start position:0% +opinion with Russell his boss who had +said that you should seek simplicity in + + align:start position:0% +said that you should seek simplicity in + + + align:start position:0% +said that you should seek simplicity in +your experiments + + align:start position:0% +your experiments + + + align:start position:0% +your experiments +and he was saying no I'm gonna do the + + align:start position:0% +and he was saying no I'm gonna do the + + + align:start position:0% +and he was saying no I'm gonna do the +exact opposite I'm gonna make my + + align:start position:0% +exact opposite I'm gonna make my + + + align:start position:0% +exact opposite I'm gonna make my +experiment as complex as I can and + + align:start position:0% +experiment as complex as I can and + + + align:start position:0% +experiment as complex as I can and +here's the motivation for doing that and + + align:start position:0% +here's the motivation for doing that and + + + align:start position:0% +here's the motivation for doing that and +this I think is one of the great results + + align:start position:0% +this I think is one of the great results + + + align:start position:0% +this I think is one of the great results +of Fischer is that he was able to + + align:start position:0% +of Fischer is that he was able to + + + align:start position:0% +of Fischer is that he was able to +demonstrate the specific value that you + + align:start position:0% +demonstrate the specific value that you + + + align:start position:0% +demonstrate the specific value that you +could you could attain by making the + + align:start position:0% +could you could attain by making the + + + align:start position:0% +could you could attain by making the +experiment complex and what we have here + + align:start position:0% +experiment complex and what we have here + + + align:start position:0% +experiment complex and what we have here +on the upper right of the slide is a + + align:start position:0% +on the upper right of the slide is a + + + align:start position:0% +on the upper right of the slide is a +cuboidal representation of the two to + + align:start position:0% +cuboidal representation of the two to + + + align:start position:0% +cuboidal representation of the two to +three factorial design this may not be + + align:start position:0% +three factorial design this may not be + + + align:start position:0% +three factorial design this may not be +the first time you've seen it in this + + align:start position:0% +the first time you've seen it in this + + + align:start position:0% +the first time you've seen it in this +course but you have the three different + + align:start position:0% +course but you have the three different + + + align:start position:0% +course but you have the three different +levels labeled as a B and C and the + + align:start position:0% +levels labeled as a B and C and the + + + align:start position:0% +levels labeled as a B and C and the +factors labeled as a B and seeing the + + align:start position:0% +factors labeled as a B and seeing the + + + align:start position:0% +factors labeled as a B and seeing the +levels indicate as pluses and minuses + + align:start position:0% +levels indicate as pluses and minuses + + + align:start position:0% +levels indicate as pluses and minuses +and the way that you would estimate the + + align:start position:0% +and the way that you would estimate the + + + align:start position:0% +and the way that you would estimate the +effect of a is by looking at the + + align:start position:0% +effect of a is by looking at the + + + align:start position:0% +effect of a is by looking at the +observations where a is at level plus + + align:start position:0% +observations where a is at level plus + + + align:start position:0% +observations where a is at level plus +taking the average of those four and + + align:start position:0% +taking the average of those four and + + + align:start position:0% +taking the average of those four and +then taking all of the observations + + align:start position:0% +then taking all of the observations + + + align:start position:0% +then taking all of the observations +where a is at minus and taking the + + align:start position:0% +where a is at minus and taking the + + + align:start position:0% +where a is at minus and taking the +average of those four and looking at + + align:start position:0% +average of those four and looking at + + + align:start position:0% +average of those four and looking at +that difference and that's the equation + + align:start position:0% +that difference and that's the equation + + + align:start position:0% +that difference and that's the equation +here the effect of a is defined as this + + align:start position:0% +here the effect of a is defined as this + + + align:start position:0% +here the effect of a is defined as this +equation which just implements what I + + align:start position:0% +equation which just implements what I + + + align:start position:0% +equation which just implements what I +just described in words and then what + + align:start position:0% +just described in words and then what + + + align:start position:0% +just described in words and then what +Fisher is able to show is that the + + align:start position:0% +Fisher is able to show is that the + + + align:start position:0% +Fisher is able to show is that the +standard deviation of the effect + + align:start position:0% +standard deviation of the effect + + + align:start position:0% +standard deviation of the effect +estimate has a the following form it is + + align:start position:0% +estimate has a the following form it is + + + align:start position:0% +estimate has a the following form it is +a function of the experimental error if + + align:start position:0% +a function of the experimental error if + + + align:start position:0% +a function of the experimental error if +I model the random variations in the + + align:start position:0% +I model the random variations in the + + + align:start position:0% +I model the random variations in the +observation do - let's say soil pH or + + align:start position:0% +observation do - let's say soil pH or + + + align:start position:0% +observation do - let's say soil pH or +the pests that I spoke of earlier or + + align:start position:0% +the pests that I spoke of earlier or + + + align:start position:0% +the pests that I spoke of earlier or +uneven distribution of water on the + + align:start position:0% +uneven distribution of water on the + + + align:start position:0% +uneven distribution of water on the +fields if all those nuisance factors + + align:start position:0% +fields if all those nuisance factors + + + align:start position:0% +fields if all those nuisance factors +that I didn't control influenced my + + align:start position:0% +that I didn't control influenced my + + + align:start position:0% +that I didn't control influenced my +yields at the various locations and + + align:start position:0% +yields at the various locations and + + + align:start position:0% +yields at the various locations and +those contribute to Sigma sub epsilon + + align:start position:0% +those contribute to Sigma sub epsilon + + + align:start position:0% +those contribute to Sigma sub epsilon +those will be reflected in Sigma sub a + + align:start position:0% +those will be reflected in Sigma sub a + + + align:start position:0% +those will be reflected in Sigma sub a +my estimate of the influence of say + + align:start position:0% +my estimate of the influence of say + + + align:start position:0% +my estimate of the influence of say +applying the fertilizer early or late + + align:start position:0% +applying the fertilizer early or late + + + align:start position:0% +applying the fertilizer early or late +but they are reflected in Sigma sub a + + align:start position:0% +but they are reflected in Sigma sub a + + + align:start position:0% +but they are reflected in Sigma sub a +substantially less if I use this + + align:start position:0% +substantially less if I use this + + + align:start position:0% +substantially less if I use this +factorial design rather than a single + + align:start position:0% +factorial design rather than a single + + + align:start position:0% +factorial design rather than a single +factor experiment and he could show that + + align:start position:0% +factor experiment and he could show that + + + align:start position:0% +factor experiment and he could show that +for the case of the two to the three + + align:start position:0% +for the case of the two to the three + + + align:start position:0% +for the case of the two to the three +full factorial the improvement in + + align:start position:0% +full factorial the improvement in + + + align:start position:0% +full factorial the improvement in +efficiency is a factor of two so it's a + + align:start position:0% +efficiency is a factor of two so it's a + + + align:start position:0% +efficiency is a factor of two so it's a +large benefit as compared to the + + align:start position:0% +large benefit as compared to the + + + align:start position:0% +large benefit as compared to the +benefits that you could derive by a + + align:start position:0% +benefits that you could derive by a + + + align:start position:0% +benefits that you could derive by a +different kind of analysis of the data + + align:start position:0% +different kind of analysis of the data + + + align:start position:0% +different kind of analysis of the data +the planning of the data made a huge + + align:start position:0% +the planning of the data made a huge + + + align:start position:0% +the planning of the data made a huge +difference but the problem is that if + + align:start position:0% +difference but the problem is that if + + + align:start position:0% +difference but the problem is that if +you're using a full factorial experiment + + align:start position:0% +you're using a full factorial experiment + + + align:start position:0% +you're using a full factorial experiment +you see 2 to 3 or 2 to the K the scaling + + align:start position:0% +you see 2 to 3 or 2 to the K the scaling + + + align:start position:0% +you see 2 to 3 or 2 to the K the scaling +with the number of factors is terrible + + align:start position:0% +with the number of factors is terrible + + + align:start position:0% +with the number of factors is terrible +right and so you find that you can't run + + align:start position:0% +right and so you find that you can't run + + + align:start position:0% +right and so you find that you can't run +such experiments with more than say 7 + + align:start position:0% +such experiments with more than say 7 + + + align:start position:0% +such experiments with more than say 7 +factors that's about the largest that + + align:start position:0% +factors that's about the largest that + + + align:start position:0% +factors that's about the largest that +I've seen published in tables so that we + + align:start position:0% +I've seen published in tables so that we + + + align:start position:0% +I've seen published in tables so that we +can analyze them because then you have + + align:start position:0% +can analyze them because then you have + + + align:start position:0% +can analyze them because then you have +128 data elements to include in the + + align:start position:0% +128 data elements to include in the + + + align:start position:0% +128 data elements to include in the +appendix of your paper so they're rarely + + align:start position:0% +appendix of your paper so they're rarely + + + align:start position:0% +appendix of your paper so they're rarely +run with more than 7 factors and yet in + + align:start position:0% +run with more than 7 factors and yet in + + + align:start position:0% +run with more than 7 factors and yet in +an experimentation especially in + + align:start position:0% +an experimentation especially in + + + align:start position:0% +an experimentation especially in +engineering we often have many more than + + align:start position:0% +engineering we often have many more than + + + align:start position:0% +engineering we often have many more than +7 factors we're concerned with that's + + align:start position:0% +7 factors we're concerned with that's + + + align:start position:0% +7 factors we're concerned with that's +not at all uncommon and so almost + + align:start position:0% +not at all uncommon and so almost + + + align:start position:0% +not at all uncommon and so almost +immediately Fisher begins to consider + + align:start position:0% +immediately Fisher begins to consider + + + align:start position:0% +immediately Fisher begins to consider +the possibility of some means to reduce + + align:start position:0% +the possibility of some means to reduce + + + align:start position:0% +the possibility of some means to reduce +the size of the experiment even as the + + align:start position:0% +the size of the experiment even as the + + + align:start position:0% +the size of the experiment even as the +number of factors goes up and this is + + align:start position:0% +number of factors goes up and this is + + + align:start position:0% +number of factors goes up and this is +the way he describes thinking about that + + align:start position:0% +the way he describes thinking about that + + + align:start position:0% +the way he describes thinking about that +you you deliberately sacrifice + + align:start position:0% +you you deliberately sacrifice + + + align:start position:0% +you you deliberately sacrifice +possibility of obtaining information on + + align:start position:0% +possibility of obtaining information on + + + align:start position:0% +possibility of obtaining information on +some points so you decide there are + + align:start position:0% +some points so you decide there are + + + align:start position:0% +some points so you decide there are +certain things that you would be able to + + align:start position:0% +certain things that you would be able to + + + align:start position:0% +certain things that you would be able to +estimate in the full factorial but you + + align:start position:0% +estimate in the full factorial but you + + + align:start position:0% +estimate in the full factorial but you +just decide ahead of time that they're + + align:start position:0% +just decide ahead of time that they're + + + align:start position:0% +just decide ahead of time that they're +there they're not worth investigating + + align:start position:0% +there they're not worth investigating + + + align:start position:0% +there they're not worth investigating +that maybe they're unlikely a priori and + + align:start position:0% + + + + align:start position:0% + +so you design the experiment so that you + + align:start position:0% +so you design the experiment so that you + + + align:start position:0% +so you design the experiment so that you +can't possibly obtain information about + + align:start position:0% +can't possibly obtain information about + + + align:start position:0% +can't possibly obtain information about +them but actually it's a little worse + + align:start position:0% +them but actually it's a little worse + + + align:start position:0% +them but actually it's a little worse +than that I'm going to show you later + + align:start position:0% +than that I'm going to show you later + + + align:start position:0% +than that I'm going to show you later +not only do you not have a possibility + + align:start position:0% +not only do you not have a possibility + + + align:start position:0% +not only do you not have a possibility +of obtaining information about those + + align:start position:0% +of obtaining information about those + + + align:start position:0% +of obtaining information about those +points + + align:start position:0% +points + + + align:start position:0% +points +those specific points if they were to be + + align:start position:0% +those specific points if they were to be + + + align:start position:0% +those specific points if they were to be +consequential in the end would actually + + align:start position:0% +consequential in the end would actually + + + align:start position:0% +consequential in the end would actually +interfere considerably with your ability + + align:start position:0% +interfere considerably with your ability + + + align:start position:0% +interfere considerably with your ability +to make inferences and so this is the + + align:start position:0% +to make inferences and so this is the + + + align:start position:0% +to make inferences and so this is the +simplest fractional factorial I can show + + align:start position:0% +simplest fractional factorial I can show + + + align:start position:0% +simplest fractional factorial I can show +you again we have the cuboidal + + align:start position:0% +you again we have the cuboidal + + + align:start position:0% +you again we have the cuboidal +representation and what we do is just to + + align:start position:0% +representation and what we do is just to + + + align:start position:0% +representation and what we do is just to +make observations at half of the + + align:start position:0% +make observations at half of the + + + align:start position:0% +make observations at half of the +vertices so I indicate those by the + + align:start position:0% +vertices so I indicate those by the + + + align:start position:0% +vertices so I indicate those by the +black pluses and these four are selected + + align:start position:0% +black pluses and these four are selected + + + align:start position:0% +black pluses and these four are selected +and a specific arrangement to give us + + align:start position:0% +and a specific arrangement to give us + + + align:start position:0% +and a specific arrangement to give us +the two to the three minus 1/2 fraction + + align:start position:0% +the two to the three minus 1/2 fraction + + + align:start position:0% +the two to the three minus 1/2 fraction +with resolution three I'll describe what + + align:start position:0% +with resolution three I'll describe what + + + align:start position:0% +with resolution three I'll describe what +resolution three means and a second one + + align:start position:0% +resolution three means and a second one + + + align:start position:0% +resolution three means and a second one +of the things that's interesting about + + align:start position:0% +of the things that's interesting about + + + align:start position:0% +of the things that's interesting about +the experiment in my mind is its + + align:start position:0% +the experiment in my mind is its + + + align:start position:0% +the experiment in my mind is its +projective properties so we see that if + + align:start position:0% +projective properties so we see that if + + + align:start position:0% +projective properties so we see that if +we collapse factor a that is if we + + align:start position:0% +we collapse factor a that is if we + + + align:start position:0% +we collapse factor a that is if we +imagine that there is a flashlight or + + align:start position:0% +imagine that there is a flashlight or + + + align:start position:0% +imagine that there is a flashlight or +such a source of light off to the right + + align:start position:0% +such a source of light off to the right + + + align:start position:0% +such a source of light off to the right +and we get a projection of the matrix of + + align:start position:0% +and we get a projection of the matrix of + + + align:start position:0% +and we get a projection of the matrix of +the cube and now we just get a square we + + align:start position:0% +the cube and now we just get a square we + + + align:start position:0% +the cube and now we just get a square we +see that if factor a has collapsed we + + align:start position:0% +see that if factor a has collapsed we + + + align:start position:0% +see that if factor a has collapsed we +would have a full factorial experiment + + align:start position:0% +would have a full factorial experiment + + + align:start position:0% +would have a full factorial experiment +in B and C have you studied these + + align:start position:0% +in B and C have you studied these + + + align:start position:0% +in B and C have you studied these +projective properties and the other + + align:start position:0% +projective properties and the other + + + align:start position:0% +projective properties and the other +parts of the course okay and so it goes + + align:start position:0% +parts of the course okay and so it goes + + + align:start position:0% +parts of the course okay and so it goes +in the other dimensions as well and so + + align:start position:0% +in the other dimensions as well and so + + + align:start position:0% +in the other dimensions as well and so +in my mind what's interesting about this + + align:start position:0% +in my mind what's interesting about this + + + align:start position:0% +in my mind what's interesting about this +is that in a way the design of the + + align:start position:0% +is that in a way the design of the + + + align:start position:0% +is that in a way the design of the +experiment allows you to account for a + + align:start position:0% +experiment allows you to account for a + + + align:start position:0% +experiment allows you to account for a +particular kind of uncertainty if you + + align:start position:0% +particular kind of uncertainty if you + + + align:start position:0% +particular kind of uncertainty if you +have a long list of factors and you're + + align:start position:0% +have a long list of factors and you're + + + align:start position:0% +have a long list of factors and you're +not sure which ones are going to be the + + align:start position:0% +not sure which ones are going to be the + + + align:start position:0% +not sure which ones are going to be the +important ones you know that some few + + align:start position:0% +important ones you know that some few + + + align:start position:0% +important ones you know that some few +will turn out to be important but you're + + align:start position:0% +will turn out to be important but you're + + + align:start position:0% +will turn out to be important but you're +not sure which ones you can arrange it + + align:start position:0% +not sure which ones you can arrange it + + + align:start position:0% +not sure which ones you can arrange it +so that you will have done a full + + align:start position:0% +so that you will have done a full + + + align:start position:0% +so that you will have done a full +factorial in the few important factors + + align:start position:0% +factorial in the few important factors + + + align:start position:0% +factorial in the few important factors +without knowing exactly which ones you + + align:start position:0% +without knowing exactly which ones you + + + align:start position:0% +without knowing exactly which ones you +need to do a full factorial experiment + + align:start position:0% +need to do a full factorial experiment + + + align:start position:0% +need to do a full factorial experiment +in and that's what the projective + + align:start position:0% +in and that's what the projective + + + align:start position:0% +in and that's what the projective +properties allow you to do but all this + + align:start position:0% +properties allow you to do but all this + + + align:start position:0% +properties allow you to do but all this +comes at a cost and the cost is more + + align:start position:0% +comes at a cost and the cost is more + + + align:start position:0% +comes at a cost and the cost is more +easily described by looking at + + align:start position:0% +easily described by looking at + + + align:start position:0% +easily described by looking at +a larger fractional factorial experiment + + align:start position:0% +a larger fractional factorial experiment + + + align:start position:0% +a larger fractional factorial experiment +this is the to the 7-4 design and what + + align:start position:0% +this is the to the 7-4 design and what + + + align:start position:0% +this is the to the 7-4 design and what +we see here is that if we have seven + + align:start position:0% +we see here is that if we have seven + + + align:start position:0% +we see here is that if we have seven +factors and we want to stuff them into a + + align:start position:0% +factors and we want to stuff them into a + + + align:start position:0% +factors and we want to stuff them into a +small experiment with just say eight + + align:start position:0% +small experiment with just say eight + + + align:start position:0% +small experiment with just say eight +trials then what we can do is put them + + align:start position:0% +trials then what we can do is put them + + + align:start position:0% +trials then what we can do is put them +in this arrangement and the risk is that + + align:start position:0% +in this arrangement and the risk is that + + + align:start position:0% +in this arrangement and the risk is that +if for example there is a two factor + + align:start position:0% +if for example there is a two factor + + + align:start position:0% +if for example there is a two factor +interaction between F and G then that + + align:start position:0% +interaction between F and G then that + + + align:start position:0% +interaction between F and G then that +will emerge in this pattern that in the + + align:start position:0% +will emerge in this pattern that in the + + + align:start position:0% +will emerge in this pattern that in the +first four experiments F and G are all + + align:start position:0% +first four experiments F and G are all + + + align:start position:0% +first four experiments F and G are all +at the same level either plus and plus + + align:start position:0% +at the same level either plus and plus + + + align:start position:0% +at the same level either plus and plus +or minus and minus and in the last four + + align:start position:0% +or minus and minus and in the last four + + + align:start position:0% +or minus and minus and in the last four +experiments they're all at different + + align:start position:0% +experiments they're all at different + + + align:start position:0% +experiments they're all at different +levels such as minus and plus or plus + + align:start position:0% +levels such as minus and plus or plus + + + align:start position:0% +levels such as minus and plus or plus +and minus and so if the two are + + align:start position:0% +and minus and so if the two are + + + align:start position:0% +and minus and so if the two are +interacting in some important way the + + align:start position:0% +interacting in some important way the + + + align:start position:0% +interacting in some important way the +effect will emerge in such a way that it + + align:start position:0% +effect will emerge in such a way that it + + + align:start position:0% +effect will emerge in such a way that it +is coming into being exactly when a as + + align:start position:0% +is coming into being exactly when a as + + + align:start position:0% +is coming into being exactly when a as +at - or a as a plus and so you will + + align:start position:0% +at - or a as a plus and so you will + + + align:start position:0% +at - or a as a plus and so you will +confound the two in your analysis and if + + align:start position:0% +confound the two in your analysis and if + + + align:start position:0% +confound the two in your analysis and if +you think that an effect of a itself is + + align:start position:0% +you think that an effect of a itself is + + + align:start position:0% +you think that an effect of a itself is +more likely than a two factor + + align:start position:0% +more likely than a two factor + + + align:start position:0% +more likely than a two factor +interaction of F and G you're likely to + + align:start position:0% +interaction of F and G you're likely to + + + align:start position:0% +interaction of F and G you're likely to +make a mistake - to assign that effect + + align:start position:0% +make a mistake - to assign that effect + + + align:start position:0% +make a mistake - to assign that effect +to a whereas it actually occurred due to + + align:start position:0% +to a whereas it actually occurred due to + + + align:start position:0% +to a whereas it actually occurred due to +F and G that's the risk that you have to + + align:start position:0% +F and G that's the risk that you have to + + + align:start position:0% +F and G that's the risk that you have to +take to make a relatively small + + align:start position:0% +take to make a relatively small + + + align:start position:0% +take to make a relatively small +experiment that's investigating a lot of + + align:start position:0% +experiment that's investigating a lot of + + + align:start position:0% +experiment that's investigating a lot of +potential factors so these are the trade + + align:start position:0% +potential factors so these are the trade + + + align:start position:0% +potential factors so these are the trade +offs we we make an experimental design + + align:start position:0% +offs we we make an experimental design + + + align:start position:0% +offs we we make an experimental design +now one of the reasons that this whole + + align:start position:0% +now one of the reasons that this whole + + + align:start position:0% +now one of the reasons that this whole +topic is important to engineers is that + + align:start position:0% +topic is important to engineers is that + + + align:start position:0% +topic is important to engineers is that +we're concerned with robustness robust + + align:start position:0% +we're concerned with robustness robust + + + align:start position:0% +we're concerned with robustness robust +parameter design and what I'm showing + + align:start position:0% +parameter design and what I'm showing + + + align:start position:0% +parameter design and what I'm showing +here is the cover of one of the I think + + align:start position:0% +here is the cover of one of the I think + + + align:start position:0% +here is the cover of one of the I think +probably the best modern compilation of + + align:start position:0% +probably the best modern compilation of + + + align:start position:0% +probably the best modern compilation of +this topic on experimental design and + + align:start position:0% +this topic on experimental design and + + + align:start position:0% +this topic on experimental design and +its application to engineering systems + + align:start position:0% +its application to engineering systems + + + align:start position:0% +its application to engineering systems +in particular for the pursuit of + + align:start position:0% +in particular for the pursuit of + + + align:start position:0% +in particular for the pursuit of +robustness and he and Jeff flew and + + align:start position:0% +robustness and he and Jeff flew and + + + align:start position:0% +robustness and he and Jeff flew and +Michael Hamada defined robust parameter + + align:start position:0% +Michael Hamada defined robust parameter + + + align:start position:0% +Michael Hamada defined robust parameter +design here + + align:start position:0% +design here + + + align:start position:0% +design here +as a set of statistical and engineering + + align:start position:0% +as a set of statistical and engineering + + + align:start position:0% +as a set of statistical and engineering +methodology to reduce performance + + align:start position:0% +methodology to reduce performance + + + align:start position:0% +methodology to reduce performance +variation by choosing settings of + + align:start position:0% +variation by choosing settings of + + + align:start position:0% +variation by choosing settings of +control factors to make the system less + + align:start position:0% +control factors to make the system less + + + align:start position:0% +control factors to make the system less +sensitive so you're trying to find + + align:start position:0% +sensitive so you're trying to find + + + align:start position:0% +sensitive so you're trying to find +things that you can control in an + + align:start position:0% +things that you can control in an + + + align:start position:0% +things that you can control in an +experiment in a design and to use those + + align:start position:0% +experiment in a design and to use those + + + align:start position:0% +experiment in a design and to use those +to make performance less sensitive to + + align:start position:0% +to make performance less sensitive to + + + align:start position:0% +to make performance less sensitive to +things that you don't control can you + + align:start position:0% +things that you don't control can you + + + align:start position:0% +things that you don't control can you +think of examples relevant to your work + + align:start position:0% +think of examples relevant to your work + + + align:start position:0% +think of examples relevant to your work +of something you might make robust or + + align:start position:0% +of something you might make robust or + + + align:start position:0% +of something you might make robust or +even simpler just a of a noise factor + + align:start position:0% +even simpler just a of a noise factor + + + align:start position:0% +even simpler just a of a noise factor +you might be concerned with something + + align:start position:0% +you might be concerned with something + + + align:start position:0% +you might be concerned with something +that influences a system + + align:start position:0% + + + + align:start position:0% + +well we'll have more examples later and + + align:start position:0% +well we'll have more examples later and + + + align:start position:0% +well we'll have more examples later and +in fact I believe that in the past this + + align:start position:0% +in fact I believe that in the past this + + + align:start position:0% +in fact I believe that in the past this +course has had some projects associated + + align:start position:0% +course has had some projects associated + + + align:start position:0% +course has had some projects associated +with it + + align:start position:0% +with it + + + align:start position:0% +with it +and in some cases people want to do + + align:start position:0% +and in some cases people want to do + + + align:start position:0% +and in some cases people want to do +robust Prem resign and projects yes ok + + align:start position:0% +robust Prem resign and projects yes ok + + + align:start position:0% +robust Prem resign and projects yes ok +ok so you might be doing injection + + align:start position:0% +ok so you might be doing injection + + + align:start position:0% +ok so you might be doing injection +molding or a process like that and you + + align:start position:0% +molding or a process like that and you + + + align:start position:0% +molding or a process like that and you +kit you you could control temperature + + align:start position:0% +kit you you could control temperature + + + align:start position:0% +kit you you could control temperature +and humidity but at some great cost I + + align:start position:0% +and humidity but at some great cost I + + + align:start position:0% +and humidity but at some great cost I +guess so you might choose to allow those + + align:start position:0% +guess so you might choose to allow those + + + align:start position:0% +guess so you might choose to allow those +things to vary to some degree and if + + align:start position:0% +things to vary to some degree and if + + + align:start position:0% +things to vary to some degree and if +they influence say the geometry of your + + align:start position:0% +they influence say the geometry of your + + + align:start position:0% +they influence say the geometry of your +parts resulting parts too much you you + + align:start position:0% +parts resulting parts too much you you + + + align:start position:0% +parts resulting parts too much you you +would probably be producing less value + + align:start position:0% +would probably be producing less value + + + align:start position:0% +would probably be producing less value +to your customer probably the the + + align:start position:0% +to your customer probably the the + + + align:start position:0% +to your customer probably the the +function of your articles themselves + + align:start position:0% +function of your articles themselves + + + align:start position:0% +function of your articles themselves +might be degraded by that and so you + + align:start position:0% +might be degraded by that and so you + + + align:start position:0% +might be degraded by that and so you +might like to choose process parameters + + align:start position:0% +might like to choose process parameters + + + align:start position:0% +might like to choose process parameters +such as pressures and compositions of + + align:start position:0% +such as pressures and compositions of + + + align:start position:0% +such as pressures and compositions of +your plastic and so on so that that + + align:start position:0% +your plastic and so on so that that + + + align:start position:0% +your plastic and so on so that that +effect is minimized so you decide not to + + align:start position:0% +effect is minimized so you decide not to + + + align:start position:0% +effect is minimized so you decide not to +control the community but just to be + + align:start position:0% +control the community but just to be + + + align:start position:0% +control the community but just to be +insensitive to it they're good so on the + + align:start position:0% +insensitive to it they're good so on the + + + align:start position:0% +insensitive to it they're good so on the +cover of this textbook you see actually + + align:start position:0% +cover of this textbook you see actually + + + align:start position:0% +cover of this textbook you see actually +something called a crossed array it's + + align:start position:0% +something called a crossed array it's + + + align:start position:0% +something called a crossed array it's +hard to pick out unless you know you you + + align:start position:0% +hard to pick out unless you know you you + + + align:start position:0% +hard to pick out unless you know you you +go and zoom in on your own computer but + + align:start position:0% +go and zoom in on your own computer but + + + align:start position:0% +go and zoom in on your own computer but +you see capital A B and C over here and + + align:start position:0% +you see capital A B and C over here and + + + align:start position:0% +you see capital A B and C over here and +those represent control factors such as + + align:start position:0% +those represent control factors such as + + + align:start position:0% +those represent control factors such as +pressure and speed of the extruder and + + align:start position:0% +pressure and speed of the extruder and + + + align:start position:0% +pressure and speed of the extruder and +the composition of the plastic things + + align:start position:0% +the composition of the plastic things + + + align:start position:0% +the composition of the plastic things +that you might control nominally and + + align:start position:0% +that you might control nominally and + + + align:start position:0% +that you might control nominally and +then there's little a and B those are + + align:start position:0% +then there's little a and B those are + + + align:start position:0% +then there's little a and B those are +temperature and humidity and things you + + align:start position:0% +temperature and humidity and things you + + + align:start position:0% +temperature and humidity and things you +might decide you you're not going to + + align:start position:0% +might decide you you're not going to + + + align:start position:0% +might decide you you're not going to +control so much and you see that + + align:start position:0% +control so much and you see that + + + align:start position:0% +control so much and you see that +fractional factorial designs are or + + align:start position:0% +fractional factorial designs are or + + + align:start position:0% +fractional factorial designs are or +factorial designs are being used in each + + align:start position:0% +factorial designs are being used in each + + + align:start position:0% +factorial designs are being used in each +of these arrangements shown to the left + + align:start position:0% +of these arrangements shown to the left + + + align:start position:0% +of these arrangements shown to the left +and above and then the crossing the + + align:start position:0% +and above and then the crossing the + + + align:start position:0% +and above and then the crossing the +product of those two designs is + + align:start position:0% +product of those two designs is + + + align:start position:0% +product of those two designs is +indicated in the middle and here Wow + + align:start position:0% +indicated in the middle and here Wow + + + align:start position:0% +indicated in the middle and here Wow +actually begins to hint and foreshadow + + align:start position:0% +actually begins to hint and foreshadow + + + align:start position:0% +actually begins to hint and foreshadow +about the idea + + align:start position:0% +about the idea + + + align:start position:0% +about the idea +yeah what he calls a combiner experiment + + align:start position:0% +yeah what he calls a combiner experiment + + + align:start position:0% +yeah what he calls a combiner experiment +so he shows some of these being white + + align:start position:0% +so he shows some of these being white + + + align:start position:0% +so he shows some of these being white +and some being dark and he's suggesting + + align:start position:0% +and some being dark and he's suggesting + + + align:start position:0% +and some being dark and he's suggesting +that as a way to address the rather + + align:start position:0% +that as a way to address the rather + + + align:start position:0% +that as a way to address the rather +large size of this experiment so it + + align:start position:0% +large size of this experiment so it + + + align:start position:0% +large size of this experiment so it +turns out that the first person to + + align:start position:0% +turns out that the first person to + + + align:start position:0% +turns out that the first person to +pioneer this idea of bringing in + + align:start position:0% +pioneer this idea of bringing in + + + align:start position:0% +pioneer this idea of bringing in +fractional factorial designs into the + + align:start position:0% +fractional factorial designs into the + + + align:start position:0% +fractional factorial designs into the +plant and using them explicitly for the + + align:start position:0% +plant and using them explicitly for the + + + align:start position:0% +plant and using them explicitly for the +purpose of robustness improvements + + align:start position:0% +purpose of robustness improvements + + + align:start position:0% +purpose of robustness improvements +person who seems to most often get + + align:start position:0% +person who seems to most often get + + + align:start position:0% +person who seems to most often get +credit for this is Taguchi in Japan so + + align:start position:0% +credit for this is Taguchi in Japan so + + + align:start position:0% +credit for this is Taguchi in Japan so +he begins to do work in Japan after + + align:start position:0% +he begins to do work in Japan after + + + align:start position:0% +he begins to do work in Japan after +World War two when they're their + + align:start position:0% +World War two when they're their + + + align:start position:0% +World War two when they're their +manufacturing bases in disarray and + + align:start position:0% +manufacturing bases in disarray and + + + align:start position:0% +manufacturing bases in disarray and +their economy is in not good shape and + + align:start position:0% +their economy is in not good shape and + + + align:start position:0% +their economy is in not good shape and +their reputation for manufacturing is + + align:start position:0% +their reputation for manufacturing is + + + align:start position:0% +their reputation for manufacturing is +very poor at that time too so if you + + align:start position:0% +very poor at that time too so if you + + + align:start position:0% +very poor at that time too so if you +bought a product and said made in Japan + + align:start position:0% +bought a product and said made in Japan + + + align:start position:0% +bought a product and said made in Japan +on it people would actually imagine that + + align:start position:0% +on it people would actually imagine that + + + align:start position:0% +on it people would actually imagine that +that meant it was of rather poor quality + + align:start position:0% +that meant it was of rather poor quality + + + align:start position:0% +that meant it was of rather poor quality +and of course our impression is totally + + align:start position:0% +and of course our impression is totally + + + align:start position:0% +and of course our impression is totally +the opposite now and it's interesting to + + align:start position:0% +the opposite now and it's interesting to + + + align:start position:0% +the opposite now and it's interesting to +consider how that happened it was a lot + + align:start position:0% +consider how that happened it was a lot + + + align:start position:0% +consider how that happened it was a lot +of different things but maybe one of the + + align:start position:0% +of different things but maybe one of the + + + align:start position:0% +of different things but maybe one of the +things that brought that change about + + align:start position:0% +things that brought that change about + + + align:start position:0% +things that brought that change about +and our perception of Japanese + + align:start position:0% +and our perception of Japanese + + + align:start position:0% +and our perception of Japanese +manufacturer was some of this + + align:start position:0% +manufacturer was some of this + + + align:start position:0% +manufacturer was some of this +methodology and Taguchi correctly + + align:start position:0% +methodology and Taguchi correctly + + + align:start position:0% +methodology and Taguchi correctly +pointed out that robustness could be + + align:start position:0% +pointed out that robustness could be + + + align:start position:0% +pointed out that robustness could be +attained and it could be attained + + align:start position:0% +attained and it could be attained + + + align:start position:0% +attained and it could be attained +through experimentation and he suggested + + align:start position:0% +through experimentation and he suggested + + + align:start position:0% +through experimentation and he suggested +that you might for example run an + + align:start position:0% +that you might for example run an + + + align:start position:0% +that you might for example run an +experiment like this in our fog array or + + align:start position:0% +experiment like this in our fog array or + + + align:start position:0% +experiment like this in our fog array or +factorial design and control factors + + align:start position:0% +factorial design and control factors + + + align:start position:0% +factorial design and control factors +crossed with noise factors and in this + + align:start position:0% +crossed with noise factors and in this + + + align:start position:0% +crossed with noise factors and in this +case you take your eight run array of + + align:start position:0% +case you take your eight run array of + + + align:start position:0% +case you take your eight run array of +control factors cross it with your four + + align:start position:0% +control factors cross it with your four + + + align:start position:0% +control factors cross it with your four +run array of noise factors and you would + + align:start position:0% +run array of noise factors and you would + + + align:start position:0% +run array of noise factors and you would +have a thirty-two run cross array and so + + align:start position:0% +have a thirty-two run cross array and so + + + align:start position:0% +have a thirty-two run cross array and so +you see with this cross symbol the + + align:start position:0% +you see with this cross symbol the + + + align:start position:0% +you see with this cross symbol the +implication is that the size of the + + align:start position:0% +implication is that the size of the + + + align:start position:0% +implication is that the size of the +experiment scales at least like the + + align:start position:0% +experiment scales at least like the + + + align:start position:0% +experiment scales at least like the +product of the number of control factors + + align:start position:0% +product of the number of control factors + + + align:start position:0% +product of the number of control factors +plus one and the number of noise factors + + align:start position:0% +plus one and the number of noise factors + + + align:start position:0% +plus one and the number of noise factors +plus one which you know when you begin + + align:start position:0% +plus one which you know when you begin + + + align:start position:0% +plus one which you know when you begin +to consider lots of control of noise + + align:start position:0% +to consider lots of control of noise + + + align:start position:0% +to consider lots of control of noise +factors it gets awfully burdensome so + + align:start position:0% +factors it gets awfully burdensome so + + + align:start position:0% +factors it gets awfully burdensome so +people are looking for ways to do it + + align:start position:0% +people are looking for ways to do it + + + align:start position:0% +people are looking for ways to do it +more fish + + align:start position:0% +more fish + + + align:start position:0% +more fish +we and that leads to the cover of this + + align:start position:0% +we and that leads to the cover of this + + + align:start position:0% +we and that leads to the cover of this +this textbook the idea of just doing + + align:start position:0% +this textbook the idea of just doing + + + align:start position:0% +this textbook the idea of just doing +half of them so that you're actually not + + align:start position:0% +half of them so that you're actually not + + + align:start position:0% +half of them so that you're actually not +running exactly the same noise + + align:start position:0% +running exactly the same noise + + + align:start position:0% +running exactly the same noise +conditions at every setting of the + + align:start position:0% +conditions at every setting of the + + + align:start position:0% +conditions at every setting of the +control factors and what we've done in + + align:start position:0% +control factors and what we've done in + + + align:start position:0% +control factors and what we've done in +our methodology validation work actually + + align:start position:0% +our methodology validation work actually + + + align:start position:0% +our methodology validation work actually +is the show in a recent publication and + + align:start position:0% +is the show in a recent publication and + + + align:start position:0% +is the show in a recent publication and +journal quality technology that this + + align:start position:0% +journal quality technology that this + + + align:start position:0% +journal quality technology that this +procedure although theoretically looks + + align:start position:0% +procedure although theoretically looks + + + align:start position:0% +procedure although theoretically looks +promising + + align:start position:0% +promising + + + align:start position:0% +promising +in many specific cases it's failing + + align:start position:0% + + + + align:start position:0% + +and yet you know if I if I look at + + align:start position:0% +and yet you know if I if I look at + + + align:start position:0% +and yet you know if I if I look at +industry practice today + + align:start position:0% +industry practice today + + + align:start position:0% +industry practice today +I think the methods of Taguchi and also + + align:start position:0% +I think the methods of Taguchi and also + + + align:start position:0% +I think the methods of Taguchi and also +the refinements proposed more recently + + align:start position:0% +the refinements proposed more recently + + + align:start position:0% +the refinements proposed more recently +on the basis of statistical theory are + + align:start position:0% +on the basis of statistical theory are + + + align:start position:0% +on the basis of statistical theory are +finding their way into industry practice + + align:start position:0% +finding their way into industry practice + + + align:start position:0% +finding their way into industry practice +and are really quite solidly entrenched + + align:start position:0% +and are really quite solidly entrenched + + + align:start position:0% +and are really quite solidly entrenched +so some of you may have had some + + align:start position:0% +so some of you may have had some + + + align:start position:0% +so some of you may have had some +experience with these Six Sigma programs + + align:start position:0% +experience with these Six Sigma programs + + + align:start position:0% +experience with these Six Sigma programs +by now maybe some of you are in General + + align:start position:0% +by now maybe some of you are in General + + + align:start position:0% +by now maybe some of you are in General +Electric maybe some in Motorola and I + + align:start position:0% +Electric maybe some in Motorola and I + + + align:start position:0% +Electric maybe some in Motorola and I +guess many other companies by now have + + align:start position:0% +guess many other companies by now have + + + align:start position:0% +guess many other companies by now have +such programs and a big part of such + + align:start position:0% +such programs and a big part of such + + + align:start position:0% +such programs and a big part of such +programs is that entering engineers will + + align:start position:0% +programs is that entering engineers will + + + align:start position:0% +programs is that entering engineers will +take some coursework even if they didn't + + align:start position:0% +take some coursework even if they didn't + + + align:start position:0% +take some coursework even if they didn't +get it in their undergraduate degrees + + align:start position:0% +get it in their undergraduate degrees + + + align:start position:0% +get it in their undergraduate degrees +they the company feels people broadly + + align:start position:0% +they the company feels people broadly + + + align:start position:0% +they the company feels people broadly +need this and so they get some + + align:start position:0% +need this and so they get some + + + align:start position:0% +need this and so they get some +coursework and then they do projects + + align:start position:0% +coursework and then they do projects + + + align:start position:0% +coursework and then they do projects +right and they demonstrate that they can + + align:start position:0% +right and they demonstrate that they can + + + align:start position:0% +right and they demonstrate that they can +do some of this kind of work for the + + align:start position:0% +do some of this kind of work for the + + + align:start position:0% +do some of this kind of work for the +company and afford at least the last + + align:start position:0% +company and afford at least the last + + + align:start position:0% +company and afford at least the last +time I checked their their design + + align:start position:0% +time I checked their their design + + + align:start position:0% +time I checked their their design +process and code it just this sort of + + align:start position:0% +process and code it just this sort of + + + align:start position:0% +process and code it just this sort of +thing and they have their multi-step + + align:start position:0% +thing and they have their multi-step + + + align:start position:0% +thing and they have their multi-step +process for attaining reliability and + + align:start position:0% +process for attaining reliability and + + + align:start position:0% +process for attaining reliability and +robustness and in step four I dig in and + + align:start position:0% +robustness and in step four I dig in and + + + align:start position:0% +robustness and in step four I dig in and +look at the details and the engineers + + align:start position:0% +look at the details and the engineers + + + align:start position:0% +look at the details and the engineers +are asked to select appropriate + + align:start position:0% +are asked to select appropriate + + + align:start position:0% +are asked to select appropriate +orthogonal arrays so the idea is that + + align:start position:0% +orthogonal arrays so the idea is that + + + align:start position:0% +orthogonal arrays so the idea is that +maybe they have some choices about what + + align:start position:0% +maybe they have some choices about what + + + align:start position:0% +maybe they have some choices about what +size are orthogonal array number of + + align:start position:0% +size are orthogonal array number of + + + align:start position:0% +size are orthogonal array number of +levels the crossed array versus the + + align:start position:0% +levels the crossed array versus the + + + align:start position:0% +levels the crossed array versus the +combined array such as Wu talked about + + align:start position:0% +combined array such as Wu talked about + + + align:start position:0% +combined array such as Wu talked about +but departure from North Ogden will + + align:start position:0% +but departure from North Ogden will + + + align:start position:0% +but departure from North Ogden will +raise itself is not really being + + align:start position:0% +raise itself is not really being + + + align:start position:0% +raise itself is not really being +considered anymore in industry and so + + align:start position:0% +considered anymore in industry and so + + + align:start position:0% +considered anymore in industry and so +this has become very much entrenched and + + align:start position:0% +this has become very much entrenched and + + + align:start position:0% +this has become very much entrenched and +in fact in some of the text books you + + align:start position:0% +in fact in some of the text books you + + + align:start position:0% +in fact in some of the text books you +see an even more extreme statement of + + align:start position:0% +see an even more extreme statement of + + + align:start position:0% +see an even more extreme statement of +the point in in this text they argue + + align:start position:0% +the point in in this text they argue + + + align:start position:0% +the point in in this text they argue +that the the idea that Edward John + + align:start position:0% +that the the idea that Edward John + + + align:start position:0% +that the the idea that Edward John +Russell expressed on that earlier slide + + align:start position:0% +Russell expressed on that earlier slide + + + align:start position:0% +Russell expressed on that earlier slide +that simplicity should be valued and + + align:start position:0% +that simplicity should be valued and + + + align:start position:0% +that simplicity should be valued and +that single factor experiments are often + + align:start position:0% +that single factor experiments are often + + + align:start position:0% +that single factor experiments are often +advisable that has seen its final demise + + align:start position:0% +advisable that has seen its final demise + + + align:start position:0% +advisable that has seen its final demise +so that's + + align:start position:0% +so that's + + + align:start position:0% +so that's +the opinion voiced in this particular + + align:start position:0% +the opinion voiced in this particular + + + align:start position:0% +the opinion voiced in this particular +textbook but we wanted to question this + + align:start position:0% +textbook but we wanted to question this + + + align:start position:0% +textbook but we wanted to question this +a little bit we wondered if sometimes + + align:start position:0% +a little bit we wondered if sometimes + + + align:start position:0% +a little bit we wondered if sometimes +there isn't a role for this the simpler + + align:start position:0% +there isn't a role for this the simpler + + + align:start position:0% +there isn't a role for this the simpler +experiment still and this decision to + + align:start position:0% +experiment still and this decision to + + + align:start position:0% +experiment still and this decision to +spend some time looking into this came + + align:start position:0% +spend some time looking into this came + + + align:start position:0% +spend some time looking into this came +out of some observations in industry and + + align:start position:0% +out of some observations in industry and + + + align:start position:0% +out of some observations in industry and +I thought it would in some ways now it + + align:start position:0% +I thought it would in some ways now it + + + align:start position:0% +I thought it would in some ways now it +it seems ironic to me that our initial + + align:start position:0% +it seems ironic to me that our initial + + + align:start position:0% +it seems ironic to me that our initial +thoughts along these lines came out of + + align:start position:0% +thoughts along these lines came out of + + + align:start position:0% +thoughts along these lines came out of +the farm again you know so that all + + align:start position:0% +the farm again you know so that all + + + align:start position:0% +the farm again you know so that all +these ideas of our thuggin arrays and so + + align:start position:0% +these ideas of our thuggin arrays and so + + + align:start position:0% +these ideas of our thuggin arrays and so +on came from agriculture in the first + + align:start position:0% +on came from agriculture in the first + + + align:start position:0% +on came from agriculture in the first +place and now our wanting to question + + align:start position:0% +place and now our wanting to question + + + align:start position:0% +place and now our wanting to question +them came off of the farm because we + + align:start position:0% +them came off of the farm because we + + + align:start position:0% +them came off of the farm because we +were working with a manufacturer of + + align:start position:0% +were working with a manufacturer of + + + align:start position:0% +were working with a manufacturer of +agricultural equipment and it seemed to + + align:start position:0% +agricultural equipment and it seemed to + + + align:start position:0% +agricultural equipment and it seemed to +me actually that farm equipment is one + + align:start position:0% +me actually that farm equipment is one + + + align:start position:0% +me actually that farm equipment is one +of the most significant robustness + + align:start position:0% +of the most significant robustness + + + align:start position:0% +of the most significant robustness +challenges in the world because what you + + align:start position:0% +challenges in the world because what you + + + align:start position:0% +challenges in the world because what you +have in a tractor or a windrow or a + + align:start position:0% +have in a tractor or a windrow or a + + + align:start position:0% +have in a tractor or a windrow or a +combine is really a factory I mean it + + align:start position:0% +combine is really a factory I mean it + + + align:start position:0% +combine is really a factory I mean it +needs to process something right + + align:start position:0% +needs to process something right + + + align:start position:0% +needs to process something right +sometimes they're not a very simple way + + align:start position:0% +sometimes they're not a very simple way + + + align:start position:0% +sometimes they're not a very simple way +you know sometimes it needs to take a + + align:start position:0% +you know sometimes it needs to take a + + + align:start position:0% +you know sometimes it needs to take a +piece of cotton off a plant and then + + align:start position:0% +piece of cotton off a plant and then + + + align:start position:0% +piece of cotton off a plant and then +strip away some part of it I mean it's + + align:start position:0% +strip away some part of it I mean it's + + + align:start position:0% +strip away some part of it I mean it's +not a simple thing and yet here it is + + align:start position:0% +not a simple thing and yet here it is + + + align:start position:0% +not a simple thing and yet here it is +and it's out in the weather it's out in + + align:start position:0% +and it's out in the weather it's out in + + + align:start position:0% +and it's out in the weather it's out in +a field whatever conditions prevail it + + align:start position:0% +a field whatever conditions prevail it + + + align:start position:0% +a field whatever conditions prevail it +has to deal with so it's a very + + align:start position:0% +has to deal with so it's a very + + + align:start position:0% +has to deal with so it's a very +difficult reliability challenge and this + + align:start position:0% +difficult reliability challenge and this + + + align:start position:0% +difficult reliability challenge and this +particular company had relatively + + align:start position:0% +particular company had relatively + + + align:start position:0% +particular company had relatively +recently brought in a lot of robust + + align:start position:0% +recently brought in a lot of robust + + + align:start position:0% +recently brought in a lot of robust +design methodology and they were looking + + align:start position:0% +design methodology and they were looking + + + align:start position:0% +design methodology and they were looking +forward to the benefits that would + + align:start position:0% +forward to the benefits that would + + + align:start position:0% +forward to the benefits that would +accrue and they got exactly the opposite + + align:start position:0% +accrue and they got exactly the opposite + + + align:start position:0% +accrue and they got exactly the opposite +that this most recent launch of a new + + align:start position:0% +that this most recent launch of a new + + + align:start position:0% +that this most recent launch of a new +tractor was one of the worst they'd ever + + align:start position:0% +tractor was one of the worst they'd ever + + + align:start position:0% +tractor was one of the worst they'd ever +had and was causing them real problems + + align:start position:0% +had and was causing them real problems + + + align:start position:0% +had and was causing them real problems +you know their customers were quite + + align:start position:0% +you know their customers were quite + + + align:start position:0% +you know their customers were quite +angry with them and so we wanted to look + + align:start position:0% +angry with them and so we wanted to look + + + align:start position:0% +angry with them and so we wanted to look +into that and we decided to in effect do + + align:start position:0% +into that and we decided to in effect do + + + align:start position:0% +into that and we decided to in effect do +an audit you know look at their design + + align:start position:0% +an audit you know look at their design + + + align:start position:0% +an audit you know look at their design +process for this tractor what had + + align:start position:0% +process for this tractor what had + + + align:start position:0% +process for this tractor what had +happened where there's some mistakes and + + align:start position:0% +happened where there's some mistakes and + + + align:start position:0% +happened where there's some mistakes and +choices of design or priority or + + align:start position:0% +choices of design or priority or + + + align:start position:0% +choices of design or priority or +management whatever so one of the things + + align:start position:0% +management whatever so one of the things + + + align:start position:0% +management whatever so one of the things +that we asked for is an accounting of + + align:start position:0% +that we asked for is an accounting of + + + align:start position:0% +that we asked for is an accounting of +all the different robust design + + align:start position:0% +all the different robust design + + + align:start position:0% +all the different robust design +experiments they had done and they gave + + align:start position:0% +experiments they had done and they gave + + + align:start position:0% +experiments they had done and they gave +us a list of experiments they planned it + + align:start position:0% +us a list of experiments they planned it + + + align:start position:0% +us a list of experiments they planned it +was a long list + + align:start position:0% +was a long list + + + align:start position:0% +was a long list +and then we said well yeah but we need + + align:start position:0% +and then we said well yeah but we need + + + align:start position:0% +and then we said well yeah but we need +more detail than this show us you know + + align:start position:0% +more detail than this show us you know + + + align:start position:0% +more detail than this show us you know +the written reports from all these + + align:start position:0% +the written reports from all these + + + align:start position:0% +the written reports from all these +experiments you know show us the data + + align:start position:0% +experiments you know show us the data + + + align:start position:0% +experiments you know show us the data +show a vision basis of the data and they + + align:start position:0% +show a vision basis of the data and they + + + align:start position:0% +show a vision basis of the data and they +gave us a much smaller list of reports + + align:start position:0% +gave us a much smaller list of reports + + + align:start position:0% +gave us a much smaller list of reports +and we said okay you had 30 and now we + + align:start position:0% +and we said okay you had 30 and now we + + + align:start position:0% +and we said okay you had 30 and now we +have five what about the other 25 and + + align:start position:0% +have five what about the other 25 and + + + align:start position:0% +have five what about the other 25 and +they said well those were never finished + + align:start position:0% +they said well those were never finished + + + align:start position:0% +they said well those were never finished +and that was interesting to us you know + + align:start position:0% +and that was interesting to us you know + + + align:start position:0% +and that was interesting to us you know +why is it that the majority weren't + + align:start position:0% +why is it that the majority weren't + + + align:start position:0% +why is it that the majority weren't +finished and we began to ask questions + + align:start position:0% +finished and we began to ask questions + + + align:start position:0% +finished and we began to ask questions +of the individuals involved and they + + align:start position:0% +of the individuals involved and they + + + align:start position:0% +of the individuals involved and they +always had pretty good reasons you know + + align:start position:0% +always had pretty good reasons you know + + + align:start position:0% +always had pretty good reasons you know +in some cases they would say that a + + align:start position:0% +in some cases they would say that a + + + align:start position:0% +in some cases they would say that a +piece of test equipment had broken down + + align:start position:0% +piece of test equipment had broken down + + + align:start position:0% +piece of test equipment had broken down +at some point along the way and was + + align:start position:0% +at some point along the way and was + + + align:start position:0% +at some point along the way and was +going to take a certain amount of time + + align:start position:0% +going to take a certain amount of time + + + align:start position:0% +going to take a certain amount of time +to repair so we had to move forward with + + align:start position:0% +to repair so we had to move forward with + + + align:start position:0% +to repair so we had to move forward with +the partial data set in fact a large + + align:start position:0% +the partial data set in fact a large + + + align:start position:0% +the partial data set in fact a large +fraction of the experiments aren't + + align:start position:0% +fraction of the experiments aren't + + + align:start position:0% +fraction of the experiments aren't +finished and this prompted us to wonder + + align:start position:0% +finished and this prompted us to wonder + + + align:start position:0% +finished and this prompted us to wonder +what would you do if you knew this from + + align:start position:0% +what would you do if you knew this from + + + align:start position:0% +what would you do if you knew this from +the outset let's say that you put a 60% + + align:start position:0% +the outset let's say that you put a 60% + + + align:start position:0% +the outset let's say that you put a 60% +probability on canceling any individual + + align:start position:0% +probability on canceling any individual + + + align:start position:0% +probability on canceling any individual +experiment you might run somewhere at a + + align:start position:0% +experiment you might run somewhere at a + + + align:start position:0% +experiment you might run somewhere at a +state of partial completion let's say + + align:start position:0% +state of partial completion let's say + + + align:start position:0% +state of partial completion let's say +that that were the case but you didn't + + align:start position:0% +that that were the case but you didn't + + + align:start position:0% +that that were the case but you didn't +know which 60 percent we're gonna be + + align:start position:0% +know which 60 percent we're gonna be + + + align:start position:0% +know which 60 percent we're gonna be +canceled because you probably don't know + + align:start position:0% +canceled because you probably don't know + + + align:start position:0% +canceled because you probably don't know +that what would you do well we thought + + align:start position:0% +that what would you do well we thought + + + align:start position:0% +that what would you do well we thought +perhaps you would do a one at a time + + align:start position:0% +perhaps you would do a one at a time + + + align:start position:0% +perhaps you would do a one at a time +experiment because then at least no + + align:start position:0% +experiment because then at least no + + + align:start position:0% +experiment because then at least no +matter what you did you would have + + align:start position:0% +matter what you did you would have + + + align:start position:0% +matter what you did you would have +stopped and the data would be relatively + + align:start position:0% +stopped and the data would be relatively + + + align:start position:0% +stopped and the data would be relatively +simple to analyze you know such as what + + align:start position:0% +simple to analyze you know such as what + + + align:start position:0% +simple to analyze you know such as what +Russell talked about and we found that + + align:start position:0% +Russell talked about and we found that + + + align:start position:0% +Russell talked about and we found that +actually some of the most prominent + + align:start position:0% +actually some of the most prominent + + + align:start position:0% +actually some of the most prominent +statisticians of the past always felt + + align:start position:0% +statisticians of the past always felt + + + align:start position:0% +statisticians of the past always felt +that there was a a role for one factor + + align:start position:0% +that there was a a role for one factor + + + align:start position:0% +that there was a a role for one factor +at a time experiments so for example you + + align:start position:0% +at a time experiments so for example you + + + align:start position:0% +at a time experiments so for example you +may have heard of Milton Friedman in a + + align:start position:0% +may have heard of Milton Friedman in a + + + align:start position:0% +may have heard of Milton Friedman in a +different context what do you know him + + align:start position:0% +different context what do you know him + + + align:start position:0% +different context what do you know him +for yes + + align:start position:0% +for yes + + + align:start position:0% +for yes +yeah Nobel Prize in Economics for market + + align:start position:0% +yeah Nobel Prize in Economics for market + + + align:start position:0% +yeah Nobel Prize in Economics for market +view of economics and Leonard Savage who + + align:start position:0% +view of economics and Leonard Savage who + + + align:start position:0% +view of economics and Leonard Savage who +had written a excellent text on + + align:start position:0% +had written a excellent text on + + + align:start position:0% +had written a excellent text on +foundations of statistics they found + + align:start position:0% +foundations of statistics they found + + + align:start position:0% +foundations of statistics they found +that an efficient design for the present + + align:start position:0% +that an efficient design for the present + + + align:start position:0% +that an efficient design for the present +purposes so that was for maximization + + align:start position:0% +purposes so that was for maximization + + + align:start position:0% +purposes so that was for maximization +ought to adjust the experimental program + + align:start position:0% +ought to adjust the experimental program + + + align:start position:0% +ought to adjust the experimental program +on each stage in light of the prior + + align:start position:0% +on each stage in light of the prior + + + align:start position:0% +on each stage in light of the prior +stages and actually what they described + + align:start position:0% +stages and actually what they described + + + align:start position:0% +stages and actually what they described +was a one factor at a time experiment + + align:start position:0% +was a one factor at a time experiment + + + align:start position:0% +was a one factor at a time experiment +and then Cuthbert Daniel talked about a + + align:start position:0% +and then Cuthbert Daniel talked about a + + + align:start position:0% +and then Cuthbert Daniel talked about a +more sort of a social or psychological + + align:start position:0% +more sort of a social or psychological + + + align:start position:0% +more sort of a social or psychological +value of of simpler experiments you know + + align:start position:0% +value of of simpler experiments you know + + + align:start position:0% +value of of simpler experiments you know +just reimposing the points that Edward + + align:start position:0% +just reimposing the points that Edward + + + align:start position:0% +just reimposing the points that Edward +John Russell had made that somehow you + + align:start position:0% +John Russell had made that somehow you + + + align:start position:0% +John Russell had made that somehow you +feel that you can react to data more + + align:start position:0% +feel that you can react to data more + + + align:start position:0% +feel that you can react to data more +rapidly or learn something from each + + align:start position:0% +rapidly or learn something from each + + + align:start position:0% +rapidly or learn something from each +rung and he talked about some criteria + + align:start position:0% +rung and he talked about some criteria + + + align:start position:0% +rung and he talked about some criteria +by which you might make that choice that + + align:start position:0% +by which you might make that choice that + + + align:start position:0% +by which you might make that choice that +for example he had a demarcation maybe + + align:start position:0% +for example he had a demarcation maybe + + + align:start position:0% +for example he had a demarcation maybe +it's okay to do it as long as the + + align:start position:0% +it's okay to do it as long as the + + + align:start position:0% +it's okay to do it as long as the +effects are at least three or four times + + align:start position:0% +effects are at least three or four times + + + align:start position:0% +effects are at least three or four times +the average random error per trial so he + + align:start position:0% +the average random error per trial so he + + + align:start position:0% +the average random error per trial so he +had based on his experience come up with + + align:start position:0% +had based on his experience come up with + + + align:start position:0% +had based on his experience come up with +a demarcation effects three or four + + align:start position:0% +a demarcation effects three or four + + + align:start position:0% +a demarcation effects three or four +times random error and we wanted to + + align:start position:0% +times random error and we wanted to + + + align:start position:0% +times random error and we wanted to +understand whether that demarcation was + + align:start position:0% +understand whether that demarcation was + + + align:start position:0% +understand whether that demarcation was +about right so we began to study a sort + + align:start position:0% +about right so we began to study a sort + + + align:start position:0% +about right so we began to study a sort +of an adaptive variant of one factor at + + align:start position:0% +of an adaptive variant of one factor at + + + align:start position:0% +of an adaptive variant of one factor at +a time experiment ation and in the + + align:start position:0% +a time experiment ation and in the + + + align:start position:0% +a time experiment ation and in the +beginning we were we were interested + + align:start position:0% +beginning we were we were interested + + + align:start position:0% +beginning we were we were interested +primarily in knowing if you were to do + + align:start position:0% +primarily in knowing if you were to do + + + align:start position:0% +primarily in knowing if you were to do +this adaptive kind of experimentation + + align:start position:0% +this adaptive kind of experimentation + + + align:start position:0% +this adaptive kind of experimentation +how how what level of probability of + + align:start position:0% +how how what level of probability of + + + align:start position:0% +how how what level of probability of +canceling the experiments would make + + align:start position:0% +canceling the experiments would make + + + align:start position:0% +canceling the experiments would make +these expert this style look good and + + align:start position:0% +these expert this style look good and + + + align:start position:0% +these expert this style look good and +the funny thing about it is we started + + align:start position:0% +the funny thing about it is we started + + + align:start position:0% +the funny thing about it is we started +with some you know maybe 50% probability + + align:start position:0% +with some you know maybe 50% probability + + + align:start position:0% +with some you know maybe 50% probability +of canceling and we looked at the to + + align:start position:0% +of canceling and we looked at the to + + + align:start position:0% +of canceling and we looked at the to +experimentation styles adaptive and + + align:start position:0% +experimentation styles adaptive and + + + align:start position:0% +experimentation styles adaptive and +factorial and on the cases we were + + align:start position:0% +factorial and on the cases we were + + + align:start position:0% +factorial and on the cases we were +looking at adaptive looked better and so + + align:start position:0% +looking at adaptive looked better and so + + + align:start position:0% +looking at adaptive looked better and so +we dialed down the probability of + + align:start position:0% +we dialed down the probability of + + + align:start position:0% +we dialed down the probability of +canceling 10% and they still looked + + align:start position:0% +canceling 10% and they still looked + + + align:start position:0% +canceling 10% and they still looked +better and we dialed down to 0% and the + + align:start position:0% +better and we dialed down to 0% and the + + + align:start position:0% +better and we dialed down to 0% and the +adaptive experiments still looked better + + align:start position:0% +adaptive experiments still looked better + + + align:start position:0% +adaptive experiments still looked better +and we thought well now we know we've + + align:start position:0% +and we thought well now we know we've + + + align:start position:0% +and we thought well now we know we've +made a mistake because we saw it in the + + align:start position:0% +made a mistake because we saw it in the + + + align:start position:0% +made a mistake because we saw it in the +textbooks that this has this kind of + + align:start position:0% +textbooks that this has this kind of + + + align:start position:0% +textbooks that this has this kind of +experimentation has seen its final + + align:start position:0% +experimentation has seen its final + + + align:start position:0% +experimentation has seen its final +demise so either we made a mistake in + + align:start position:0% +demise so either we made a mistake in + + + align:start position:0% +demise so either we made a mistake in +the way we set up the study or we chose + + align:start position:0% +the way we set up the study or we chose + + + align:start position:0% +the way we set up the study or we chose +a strange case to start with we were + + align:start position:0% +a strange case to start with we were + + + align:start position:0% +a strange case to start with we were +perplexed so we did eventually a big + + align:start position:0% +perplexed so we did eventually a big + + + align:start position:0% +perplexed so we did eventually a big +empirical evaluation and we took 66 + + align:start position:0% +empirical evaluation and we took 66 + + + align:start position:0% +empirical evaluation and we took 66 +different systems of a broad range of + + align:start position:0% +different systems of a broad range of + + + align:start position:0% +different systems of a broad range of +kinds you know chemical systems + + align:start position:0% +kinds you know chemical systems + + + align:start position:0% +kinds you know chemical systems +mechanicals + + align:start position:0% +mechanicals + + + align:start position:0% +mechanicals +electrical systems and we made our + + align:start position:0% +electrical systems and we made our + + + align:start position:0% +electrical systems and we made our +comparison in this case without + + align:start position:0% +comparison in this case without + + + align:start position:0% +comparison in this case without +canceling its now we were interested in + + align:start position:0% +canceling its now we were interested in + + + align:start position:0% +canceling its now we were interested in +that issue imagine that you're going to + + align:start position:0% +that issue imagine that you're going to + + + align:start position:0% +that issue imagine that you're going to +do it this adaptive one factor of time + + align:start position:0% +do it this adaptive one factor of time + + + align:start position:0% +do it this adaptive one factor of time +experimentation you're going to compare + + align:start position:0% +experimentation you're going to compare + + + align:start position:0% +experimentation you're going to compare +that with a fractional factorial + + align:start position:0% +that with a fractional factorial + + + align:start position:0% +that with a fractional factorial +experiment and see which one does better + + align:start position:0% +experiment and see which one does better + + + align:start position:0% +experiment and see which one does better +on average and this is what we found is + + align:start position:0% +on average and this is what we found is + + + align:start position:0% +on average and this is what we found is +that as long as experimental error was + + align:start position:0% +that as long as experimental error was + + + align:start position:0% +that as long as experimental error was +about 25 percent of combined factor + + align:start position:0% +about 25 percent of combined factor + + + align:start position:0% +about 25 percent of combined factor +effects or if interactions were large + + align:start position:0% +effects or if interactions were large + + + align:start position:0% +effects or if interactions were large +enough then you'd prefer the the + + align:start position:0% +enough then you'd prefer the the + + + align:start position:0% +enough then you'd prefer the the +adaptive experiments and so here is that + + align:start position:0% +adaptive experiments and so here is that + + + align:start position:0% +adaptive experiments and so here is that +same result shown in a tabular form so + + align:start position:0% +same result shown in a tabular form so + + + align:start position:0% +same result shown in a tabular form so +we have on the column headings the + + align:start position:0% +we have on the column headings the + + + align:start position:0% +we have on the column headings the +degree of experimental error expressed + + align:start position:0% +degree of experimental error expressed + + + align:start position:0% +degree of experimental error expressed +as a fraction of the factor effects and + + align:start position:0% +as a fraction of the factor effects and + + + align:start position:0% +as a fraction of the factor effects and +we have on the row headings the strength + + align:start position:0% +we have on the row headings the strength + + + align:start position:0% +we have on the row headings the strength +of interactions mild moderate strong + + align:start position:0% +of interactions mild moderate strong + + + align:start position:0% +of interactions mild moderate strong +dominant so strong by then strong + + align:start position:0% +dominant so strong by then strong + + + align:start position:0% +dominant so strong by then strong +interactions would indicate that the + + align:start position:0% +interactions would indicate that the + + + align:start position:0% +interactions would indicate that the +interactions are accounting for more + + align:start position:0% +interactions are accounting for more + + + align:start position:0% +interactions are accounting for more +than a quarter of you know effects in + + align:start position:0% +than a quarter of you know effects in + + + align:start position:0% +than a quarter of you know effects in +the system quite a big fraction and + + align:start position:0% +the system quite a big fraction and + + + align:start position:0% +the system quite a big fraction and +moderate is maybe you know 10 to 25 + + align:start position:0% +moderate is maybe you know 10 to 25 + + + align:start position:0% +moderate is maybe you know 10 to 25 +percent and the gray boxes indicate that + + align:start position:0% +percent and the gray boxes indicate that + + + align:start position:0% +percent and the gray boxes indicate that +the adaptive one factor time experiments + + align:start position:0% +the adaptive one factor time experiments + + + align:start position:0% +the adaptive one factor time experiments +were giving at least as good or better + + align:start position:0% +were giving at least as good or better + + + align:start position:0% +were giving at least as good or better +results than the fractional factorial + + align:start position:0% +results than the fractional factorial + + + align:start position:0% +results than the fractional factorial +and so you might prefer them especially + + align:start position:0% +and so you might prefer them especially + + + align:start position:0% +and so you might prefer them especially +given their flexibility and so we were + + align:start position:0% +given their flexibility and so we were + + + align:start position:0% +given their flexibility and so we were +surprised that how much of that + + align:start position:0% +surprised that how much of that + + + align:start position:0% +surprised that how much of that +territory turns out to be gray and that + + align:start position:0% +territory turns out to be gray and that + + + align:start position:0% +territory turns out to be gray and that +was the main result we wanted to get + + align:start position:0% +was the main result we wanted to get + + + align:start position:0% +was the main result we wanted to get +across in this paper and we thought you + + align:start position:0% +across in this paper and we thought you + + + align:start position:0% +across in this paper and we thought you +know a strength of the experimental + + align:start position:0% +know a strength of the experimental + + + align:start position:0% +know a strength of the experimental +error as large as point four looks like + + align:start position:0% +error as large as point four looks like + + + align:start position:0% +error as large as point four looks like +a lot of experimental to error to us the + + align:start position:0% +a lot of experimental to error to us the + + + align:start position:0% +a lot of experimental to error to us the +engineers when you see a dependence such + + align:start position:0% +engineers when you see a dependence such + + + align:start position:0% +engineers when you see a dependence such +as this blue line here on the figure and + + align:start position:0% +as this blue line here on the figure and + + + align:start position:0% +as this blue line here on the figure and +and the scatter being indicated by the + + align:start position:0% +and the scatter being indicated by the + + + align:start position:0% +and the scatter being indicated by the +red that's about typical of the strength + + align:start position:0% +red that's about typical of the strength + + + align:start position:0% +red that's about typical of the strength +of experimental error at point four that + + align:start position:0% +of experimental error at point four that + + + align:start position:0% +of experimental error at point four that +we expressed and to us that looks like a + + align:start position:0% +we expressed and to us that looks like a + + + align:start position:0% +we expressed and to us that looks like a +pretty noisy experiment and so we + + align:start position:0% +pretty noisy experiment and so we + + + align:start position:0% +pretty noisy experiment and so we +thought it was interesting how much of + + align:start position:0% +thought it was interesting how much of + + + align:start position:0% +thought it was interesting how much of +the time you might recommend these + + align:start position:0% +the time you might recommend these + + + align:start position:0% +the time you might recommend these +experiments + + align:start position:0% +experiments + + + align:start position:0% +experiments +so we want to understand how this could + + align:start position:0% +so we want to understand how this could + + + align:start position:0% +so we want to understand how this could +be since it seemed so counterintuitive + + align:start position:0% +be since it seemed so counterintuitive + + + align:start position:0% +be since it seemed so counterintuitive +to us and so we delved into it a little + + align:start position:0% +to us and so we delved into it a little + + + align:start position:0% +to us and so we delved into it a little +more in terms of the mathematics and we + + align:start position:0% +more in terms of the mathematics and we + + + align:start position:0% +more in terms of the mathematics and we +tried to develop a theory that would + + align:start position:0% +tried to develop a theory that would + + + align:start position:0% +tried to develop a theory that would +account for this so we started to write + + align:start position:0% +account for this so we started to write + + + align:start position:0% +account for this so we started to write +a model of the procedure of adaptive one + + align:start position:0% +a model of the procedure of adaptive one + + + align:start position:0% +a model of the procedure of adaptive one +factor time experimentation and so + + align:start position:0% +factor time experimentation and so + + + align:start position:0% +factor time experimentation and so +there's just a little notation here you + + align:start position:0% +there's just a little notation here you + + + align:start position:0% +there's just a little notation here you +imagine that you you make an initial + + align:start position:0% +imagine that you you make an initial + + + align:start position:0% +imagine that you you make an initial +observation some of the symbols are + + align:start position:0% +observation some of the symbols are + + + align:start position:0% +observation some of the symbols are +coming up a little wrong this is a x + + align:start position:0% +coming up a little wrong this is a x + + + align:start position:0% +coming up a little wrong this is a x +with a tilde over it is an initial + + align:start position:0% +with a tilde over it is an initial + + + align:start position:0% +with a tilde over it is an initial +starting point level four for factor one + + align:start position:0% +starting point level four for factor one + + + align:start position:0% +starting point level four for factor one +and X two is the tilde is the same and + + align:start position:0% +and X two is the tilde is the same and + + + align:start position:0% +and X two is the tilde is the same and +that case should be an ellipsis three + + align:start position:0% +that case should be an ellipsis three + + + align:start position:0% +that case should be an ellipsis three +dots and then you you change one of the + + align:start position:0% +dots and then you you change one of the + + + align:start position:0% +dots and then you you change one of the +factors you toggle it change it to the + + align:start position:0% +factors you toggle it change it to the + + + align:start position:0% +factors you toggle it change it to the +opposite of the starting value and + + align:start position:0% +opposite of the starting value and + + + align:start position:0% +opposite of the starting value and +that's your first observation and then + + align:start position:0% +that's your first observation and then + + + align:start position:0% +that's your first observation and then +you make a decision about the level of + + align:start position:0% +you make a decision about the level of + + + align:start position:0% +you make a decision about the level of +the first factor based on the sign of + + align:start position:0% +the first factor based on the sign of + + + align:start position:0% +the first factor based on the sign of +the differences in the observations so + + align:start position:0% +the differences in the observations so + + + align:start position:0% +the differences in the observations so +if the improvement seems to obtain we + + align:start position:0% +if the improvement seems to obtain we + + + align:start position:0% +if the improvement seems to obtain we +change we adopt the change and then we + + align:start position:0% +change we adopt the change and then we + + + align:start position:0% +change we adopt the change and then we +go through that for every one of the + + align:start position:0% +go through that for every one of the + + + align:start position:0% +go through that for every one of the +different factors you know putting stars + + align:start position:0% +different factors you know putting stars + + + align:start position:0% +different factors you know putting stars +on our X's and we continue and we what + + align:start position:0% +on our X's and we continue and we what + + + align:start position:0% +on our X's and we continue and we what +we're interested in knowing is how does + + align:start position:0% +we're interested in knowing is how does + + + align:start position:0% +we're interested in knowing is how does +the expected value of improvement behave + + align:start position:0% +the expected value of improvement behave + + + align:start position:0% +the expected value of improvement behave +as a function of a number of parameters + + align:start position:0% +as a function of a number of parameters + + + align:start position:0% +as a function of a number of parameters +in a model and the parameters we put in + + align:start position:0% +in a model and the parameters we put in + + + align:start position:0% +in a model and the parameters we put in +our model are a few we talked about the + + align:start position:0% +our model are a few we talked about the + + + align:start position:0% +our model are a few we talked about the +size of main effects in general the size + + align:start position:0% +size of main effects in general the size + + + align:start position:0% +size of main effects in general the size +of interactions and the size of + + align:start position:0% +of interactions and the size of + + + align:start position:0% +of interactions and the size of +experimental error because our empirical + + align:start position:0% +experimental error because our empirical + + + align:start position:0% +experimental error because our empirical +investigation had shown that those were + + align:start position:0% +investigation had shown that those were + + + align:start position:0% +investigation had shown that those were +interesting to look at and here we show + + align:start position:0% +interesting to look at and here we show + + + align:start position:0% +interesting to look at and here we show +we wanted to normalize those with + + align:start position:0% +we wanted to normalize those with + + + align:start position:0% +we wanted to normalize those with +respect to the maximum the best that you + + align:start position:0% +respect to the maximum the best that you + + + align:start position:0% +respect to the maximum the best that you +could do so that our results could be + + align:start position:0% +could do so that our results could be + + + align:start position:0% +could do so that our results could be +easily interpreted and the another + + align:start position:0% +easily interpreted and the another + + + align:start position:0% +easily interpreted and the another +concept we introduced in this paper we + + align:start position:0% +concept we introduced in this paper we + + + align:start position:0% +concept we introduced in this paper we +we felt we needed to explain the results + + align:start position:0% +we felt we needed to explain the results + + + align:start position:0% +we felt we needed to explain the results +was the idea of exploiting an effect + + align:start position:0% +was the idea of exploiting an effect + + + align:start position:0% +was the idea of exploiting an effect +so we entered into introduced the idea + + align:start position:0% +so we entered into introduced the idea + + + align:start position:0% +so we entered into introduced the idea +that when you do an experiment if your + + align:start position:0% +that when you do an experiment if your + + + align:start position:0% +that when you do an experiment if your +system has a number of effects in it + + align:start position:0% +system has a number of effects in it + + + align:start position:0% +system has a number of effects in it +main effects and interactions they can + + align:start position:0% +main effects and interactions they can + + + align:start position:0% +main effects and interactions they can +either be exploited or not and we'll say + + align:start position:0% +either be exploited or not and we'll say + + + align:start position:0% +either be exploited or not and we'll say +that they're exploited just in case for + + align:start position:0% +that they're exploited just in case for + + + align:start position:0% +that they're exploited just in case for +example if you're trying to get a higher + + align:start position:0% +example if you're trying to get a higher + + + align:start position:0% +example if you're trying to get a higher +response out of the system let's say + + align:start position:0% +response out of the system let's say + + + align:start position:0% +response out of the system let's say +yield out of a field of oats or quality + + align:start position:0% +yield out of a field of oats or quality + + + align:start position:0% +yield out of a field of oats or quality +of a manufactured article then you + + align:start position:0% +of a manufactured article then you + + + align:start position:0% +of a manufactured article then you +exploit an effect if the coefficient in + + align:start position:0% +exploit an effect if the coefficient in + + + align:start position:0% +exploit an effect if the coefficient in +the model times the level of the factor + + align:start position:0% +the model times the level of the factor + + + align:start position:0% +the model times the level of the factor +is such that it's contributing + + align:start position:0% +is such that it's contributing + + + align:start position:0% +is such that it's contributing +positively to your outcome and you + + align:start position:0% +positively to your outcome and you + + + align:start position:0% +positively to your outcome and you +exploit an interaction in the system + + align:start position:0% +exploit an interaction in the system + + + align:start position:0% +exploit an interaction in the system +basically under the same condition that + + align:start position:0% +basically under the same condition that + + + align:start position:0% +basically under the same condition that +if the two factors involved are such + + align:start position:0% +if the two factors involved are such + + + align:start position:0% +if the two factors involved are such +that you're gaining benefit from the + + align:start position:0% +that you're gaining benefit from the + + + align:start position:0% +that you're gaining benefit from the +coefficient in the model either + + align:start position:0% +coefficient in the model either + + + align:start position:0% +coefficient in the model either +increasing or decreasing the response + + align:start position:0% +increasing or decreasing the response + + + align:start position:0% +increasing or decreasing the response +depending on what you prefer we call + + align:start position:0% +depending on what you prefer we call + + + align:start position:0% +depending on what you prefer we call +that one exploited so we wanted to + + align:start position:0% +that one exploited so we wanted to + + + align:start position:0% +that one exploited so we wanted to +understand the probabilities and + + align:start position:0% +understand the probabilities and + + + align:start position:0% +understand the probabilities and +conditional probabilities associated + + align:start position:0% +conditional probabilities associated + + + align:start position:0% +conditional probabilities associated +with this adaptive experiment so we + + align:start position:0% +with this adaptive experiment so we + + + align:start position:0% +with this adaptive experiment so we +begin to do the the theorem proving + + align:start position:0% +begin to do the the theorem proving + + + align:start position:0% +begin to do the the theorem proving +based on our model and we find first of + + align:start position:0% +based on our model and we find first of + + + align:start position:0% +based on our model and we find first of +all that if you change just the first + + align:start position:0% +all that if you change just the first + + + align:start position:0% +all that if you change just the first +factor and compute the expected value of + + align:start position:0% +factor and compute the expected value of + + + align:start position:0% +factor and compute the expected value of +improvement you have two different kinds + + align:start position:0% +improvement you have two different kinds + + + align:start position:0% +improvement you have two different kinds +of contributions one due to a main + + align:start position:0% +of contributions one due to a main + + + align:start position:0% +of contributions one due to a main +effect and n minus one due to + + align:start position:0% +effect and n minus one due to + + + align:start position:0% +effect and n minus one due to +interactions so you change factor one + + align:start position:0% +interactions so you change factor one + + + align:start position:0% +interactions so you change factor one +and this figure here is meant to + + align:start position:0% +and this figure here is meant to + + + align:start position:0% +and this figure here is meant to +indicate the condition with N equals + + align:start position:0% +indicate the condition with N equals + + + align:start position:0% +indicate the condition with N equals +seven you've got seven factors you're + + align:start position:0% +seven you've got seven factors you're + + + align:start position:0% +seven you've got seven factors you're +interested in and this stack of squares + + align:start position:0% +interested in and this stack of squares + + + align:start position:0% +interested in and this stack of squares +indicates the contribution of main + + align:start position:0% +indicates the contribution of main + + + align:start position:0% +indicates the contribution of main +effects and and none of these other + + align:start position:0% +effects and and none of these other + + + align:start position:0% +effects and and none of these other +factors are contributing anything but + + align:start position:0% +factors are contributing anything but + + + align:start position:0% +factors are contributing anything but +now the the main effect of the first + + align:start position:0% +now the the main effect of the first + + + align:start position:0% +now the the main effect of the first +factor is contributing quite a bit on + + align:start position:0% +factor is contributing quite a bit on + + + align:start position:0% +factor is contributing quite a bit on +average after you've done the adaptation + + align:start position:0% +average after you've done the adaptation + + + align:start position:0% +average after you've done the adaptation +and all of the six potential two-factor + + align:start position:0% +and all of the six potential two-factor + + + align:start position:0% +and all of the six potential two-factor +interactions are on average contributing + + align:start position:0% +interactions are on average contributing + + + align:start position:0% +interactions are on average contributing +a little to improvement because it may + + align:start position:0% +a little to improvement because it may + + + align:start position:0% +a little to improvement because it may +be that in some cases you'll there'll be + + align:start position:0% +be that in some cases you'll there'll be + + + align:start position:0% +be that in some cases you'll there'll be +a large two factor interaction and + + align:start position:0% +a large two factor interaction and + + + align:start position:0% +a large two factor interaction and +you'll see it when you toggle the + + align:start position:0% +you'll see it when you toggle the + + + align:start position:0% +you'll see it when you toggle the +factors and you'll go chase that and so + + align:start position:0% +factors and you'll go chase that and so + + + align:start position:0% +factors and you'll go chase that and so +on average it's contributing something + + align:start position:0% +on average it's contributing something + + + align:start position:0% +on average it's contributing something +and we could write + + align:start position:0% +and we could write + + + align:start position:0% +and we could write +closed-form expressions for the + + align:start position:0% +closed-form expressions for the + + + align:start position:0% +closed-form expressions for the +contribution and the contribution due to + + align:start position:0% +contribution and the contribution due to + + + align:start position:0% +contribution and the contribution due to +main effects is larger when the main + + align:start position:0% +main effects is larger when the main + + + align:start position:0% +main effects is larger when the main +effects are larger it is tends to be + + align:start position:0% +effects are larger it is tends to be + + + align:start position:0% +effects are larger it is tends to be +smaller + + align:start position:0% +smaller + + + align:start position:0% +smaller +when interactions are large and when + + align:start position:0% +when interactions are large and when + + + align:start position:0% +when interactions are large and when +error is large the contribution to the + + align:start position:0% +error is large the contribution to the + + + align:start position:0% +error is large the contribution to the +interactions are large when interactions + + align:start position:0% +interactions are large when interactions + + + align:start position:0% +interactions are large when interactions +are large in the model and interesting + + align:start position:0% +are large in the model and interesting + + + align:start position:0% +are large in the model and interesting +to us if you if you write out the + + align:start position:0% +to us if you if you write out the + + + align:start position:0% +to us if you if you write out the +expected value normalize it by the + + align:start position:0% +expected value normalize it by the + + + align:start position:0% +expected value normalize it by the +maximum so that the improvements are + + align:start position:0% +maximum so that the improvements are + + + align:start position:0% +maximum so that the improvements are +either x' you know on this scale either + + align:start position:0% +either x' you know on this scale either + + + align:start position:0% +either x' you know on this scale either +0 or 1 + + align:start position:0% +0 or 1 + + + align:start position:0% +0 or 1 +you know or any or scaled in between the + + align:start position:0% +you know or any or scaled in between the + + + align:start position:0% +you know or any or scaled in between the +contribution you would get in in the + + align:start position:0% +contribution you would get in in the + + + align:start position:0% +contribution you would get in in the +case that experimental error is low so + + align:start position:0% +case that experimental error is low so + + + align:start position:0% +case that experimental error is low so +here I put experimental error at 10 + + align:start position:0% +here I put experimental error at 10 + + + align:start position:0% +here I put experimental error at 10 +percent of a main effect the + + align:start position:0% +percent of a main effect the + + + align:start position:0% +percent of a main effect the +contribution you get after running 1 out + + align:start position:0% +contribution you get after running 1 out + + + align:start position:0% +contribution you get after running 1 out +of 7 factors is actually about 1/7 so + + align:start position:0% +of 7 factors is actually about 1/7 so + + + align:start position:0% +of 7 factors is actually about 1/7 so +you get 1/7 of the way toward the + + align:start position:0% +you get 1/7 of the way toward the + + + align:start position:0% +you get 1/7 of the way toward the +maximum by changing 1/7 of the factors + + align:start position:0% +maximum by changing 1/7 of the factors + + + align:start position:0% +maximum by changing 1/7 of the factors +that's a good start and the influence of + + align:start position:0% +that's a good start and the influence of + + + align:start position:0% +that's a good start and the influence of +error is I mean it's there you know as + + align:start position:0% +error is I mean it's there you know as + + + align:start position:0% +error is I mean it's there you know as +you go to error being as large as main + + align:start position:0% +you go to error being as large as main + + + align:start position:0% +you go to error being as large as main +effects it drops a little and of course + + align:start position:0% +effects it drops a little and of course + + + align:start position:0% +effects it drops a little and of course +if you if you make the error really huge + + align:start position:0% +if you if you make the error really huge + + + align:start position:0% +if you if you make the error really huge +it drops quite substantially but that + + align:start position:0% +it drops quite substantially but that + + + align:start position:0% +it drops quite substantially but that +that's you know a hard test to pass but + + align:start position:0% +that's you know a hard test to pass but + + + align:start position:0% +that's you know a hard test to pass but +we're just trying to understand what the + + align:start position:0% +we're just trying to understand what the + + + align:start position:0% +we're just trying to understand what the +influences are ok now let's talk about + + align:start position:0% +influences are ok now let's talk about + + + align:start position:0% +influences are ok now let's talk about +probably the explain the first main + + align:start position:0% +probably the explain the first main + + + align:start position:0% +probably the explain the first main +effect justing when when interactions + + align:start position:0% +effect justing when when interactions + + + align:start position:0% +effect justing when when interactions +are are small the probability of getting + + align:start position:0% +are are small the probability of getting + + + align:start position:0% +are are small the probability of getting +the benefit of the main effect is large + + align:start position:0% +the benefit of the main effect is large + + + align:start position:0% +the benefit of the main effect is large +and as interactions increase it's less + + align:start position:0% +and as interactions increase it's less + + + align:start position:0% +and as interactions increase it's less +likely that you'll get the benefit of + + align:start position:0% +likely that you'll get the benefit of + + + align:start position:0% +likely that you'll get the benefit of +the main effect now it becomes + + align:start position:0% +the main effect now it becomes + + + align:start position:0% +the main effect now it becomes +interesting at the second step now + + align:start position:0% +interesting at the second step now + + + align:start position:0% +interesting at the second step now +you've toggled two factors and then when + + align:start position:0% +you've toggled two factors and then when + + + align:start position:0% +you've toggled two factors and then when +we think about it is this now you've got + + align:start position:0% +we think about it is this now you've got + + + align:start position:0% +we think about it is this now you've got +the benefit of two main effects and you + + align:start position:0% +the benefit of two main effects and you + + + align:start position:0% +the benefit of two main effects and you +get first n minus 1 and then n minus 2 + + align:start position:0% +get first n minus 1 and then n minus 2 + + + align:start position:0% +get first n minus 1 and then n minus 2 +interactions potentially contributing + + align:start position:0% +interactions potentially contributing + + + align:start position:0% +interactions potentially contributing +and at this point I hash it in because + + align:start position:0% +and at this point I hash it in because + + + align:start position:0% +and at this point I hash it in because +this is the first interaction which + + align:start position:0% +this is the first interaction which + + + align:start position:0% +this is the first interaction which +you've actually locked in in the sense + + align:start position:0% +you've actually locked in in the sense + + + align:start position:0% +you've actually locked in in the sense +that any further changes you make + + align:start position:0% +that any further changes you make + + + align:start position:0% +that any further changes you make +through the experiment + + align:start position:0% +through the experiment + + + align:start position:0% +through the experiment +process will not reverse whatever + + align:start position:0% +process will not reverse whatever + + + align:start position:0% +process will not reverse whatever +benefits you got because you've already + + align:start position:0% +benefits you got because you've already + + + align:start position:0% +benefits you got because you've already +changed one and changed two and you've + + align:start position:0% +changed one and changed two and you've + + + align:start position:0% +changed one and changed two and you've +made your decision about that and now we + + align:start position:0% +made your decision about that and now we + + + align:start position:0% +made your decision about that and now we +see that there's a contribution due to + + align:start position:0% +see that there's a contribution due to + + + align:start position:0% +see that there's a contribution due to +in the interaction and the interaction + + align:start position:0% +in the interaction and the interaction + + + align:start position:0% +in the interaction and the interaction +is the same functional form as I showed + + align:start position:0% +is the same functional form as I showed + + + align:start position:0% +is the same functional form as I showed +before that what the contribution is + + align:start position:0% +before that what the contribution is + + + align:start position:0% +before that what the contribution is +large when the interaction is large + + align:start position:0% +large when the interaction is large + + + align:start position:0% +large when the interaction is large +again + + align:start position:0% +again + + + align:start position:0% +again +we see that the the expected value is + + align:start position:0% +we see that the the expected value is + + + align:start position:0% +we see that the the expected value is +gone from about one seventh to about 2/7 + + align:start position:0% +gone from about one seventh to about 2/7 + + + align:start position:0% +gone from about one seventh to about 2/7 +so we're continuing to step forward at a + + align:start position:0% +so we're continuing to step forward at a + + + align:start position:0% +so we're continuing to step forward at a +good rate and we want to understand why + + align:start position:0% +good rate and we want to understand why + + + align:start position:0% +good rate and we want to understand why +well okay we see the probability of + + align:start position:0% +well okay we see the probability of + + + align:start position:0% +well okay we see the probability of +exploiting the interaction we can write + + align:start position:0% +exploiting the interaction we can write + + + align:start position:0% +exploiting the interaction we can write +it's close form expression it's strictly + + align:start position:0% +it's close form expression it's strictly + + + align:start position:0% +it's close form expression it's strictly +better than 50/50 so it's in any case + + align:start position:0% +better than 50/50 so it's in any case + + + align:start position:0% +better than 50/50 so it's in any case +better than random and it goes up with + + align:start position:0% +better than random and it goes up with + + + align:start position:0% +better than random and it goes up with +interaction strength now the interesting + + align:start position:0% +interaction strength now the interesting + + + align:start position:0% +interaction strength now the interesting +thing about it it's never very high + + align:start position:0% +thing about it it's never very high + + + align:start position:0% +thing about it it's never very high +because actually that any particular + + align:start position:0% +because actually that any particular + + + align:start position:0% +because actually that any particular +interaction is competing with and choose + + align:start position:0% +interaction is competing with and choose + + + align:start position:0% +interaction is competing with and choose +two other interactions or n choose two + + align:start position:0% +two other interactions or n choose two + + + align:start position:0% +two other interactions or n choose two +minus one and so any particular one is + + align:start position:0% +minus one and so any particular one is + + + align:start position:0% +minus one and so any particular one is +unlikely to be exploited by this + + align:start position:0% +unlikely to be exploited by this + + + align:start position:0% +unlikely to be exploited by this +procedure and so maybe we get a 60% + + align:start position:0% +procedure and so maybe we get a 60% + + + align:start position:0% +procedure and so maybe we get a 60% +chance but if you condition that + + align:start position:0% +chance but if you condition that + + + align:start position:0% +chance but if you condition that +probability if you say well let's say + + align:start position:0% +probability if you say well let's say + + + align:start position:0% +probability if you say well let's say +that this particular interaction we just + + align:start position:0% +that this particular interaction we just + + + align:start position:0% +that this particular interaction we just +locked in it's somehow the largest one + + align:start position:0% +locked in it's somehow the largest one + + + align:start position:0% +locked in it's somehow the largest one +in the system let's say that that + + align:start position:0% +in the system let's say that that + + + align:start position:0% +in the system let's say that that +happened we condition the probability we + + align:start position:0% +happened we condition the probability we + + + align:start position:0% +happened we condition the probability we +get a new expression and the probability + + align:start position:0% +get a new expression and the probability + + + align:start position:0% +get a new expression and the probability +could be as high as eighty percent the + + align:start position:0% +could be as high as eighty percent the + + + align:start position:0% +could be as high as eighty percent the +reason that's interesting to us is that + + align:start position:0% +reason that's interesting to us is that + + + align:start position:0% +reason that's interesting to us is that +we know that the adaptive one factor + + align:start position:0% +we know that the adaptive one factor + + + align:start position:0% +we know that the adaptive one factor +experiments are just not capable of + + align:start position:0% +experiments are just not capable of + + + align:start position:0% +experiments are just not capable of +allowing you to estimate interactions + + align:start position:0% +allowing you to estimate interactions + + + align:start position:0% +allowing you to estimate interactions +you take a factor you change it you look + + align:start position:0% +you take a factor you change it you look + + + align:start position:0% +you take a factor you change it you look +at the influence and what you're seeing + + align:start position:0% +at the influence and what you're seeing + + + align:start position:0% +at the influence and what you're seeing +is a combination of the main effect of + + align:start position:0% +is a combination of the main effect of + + + align:start position:0% +is a combination of the main effect of +the factor and a bunch of conditional + + align:start position:0% +the factor and a bunch of conditional + + + align:start position:0% +the factor and a bunch of conditional +contributions due to a bunch of + + align:start position:0% +contributions due to a bunch of + + + align:start position:0% +contributions due to a bunch of +different interactions and so you can't + + align:start position:0% +different interactions and so you can't + + + align:start position:0% +different interactions and so you can't +sort out which one is which you would + + align:start position:0% +sort out which one is which you would + + + align:start position:0% +sort out which one is which you would +need more experiments to do that + + align:start position:0% +need more experiments to do that + + + align:start position:0% +need more experiments to do that +nevertheless if there's a big effect + + align:start position:0% +nevertheless if there's a big effect + + + align:start position:0% +nevertheless if there's a big effect +there there's a good chance you'll get + + align:start position:0% +there there's a good chance you'll get + + + align:start position:0% +there there's a good chance you'll get +benefit from it when you do this + + align:start position:0% +benefit from it when you do this + + + align:start position:0% +benefit from it when you do this +adaptive experiment + + align:start position:0% +adaptive experiment + + + align:start position:0% +adaptive experiment +and so + + align:start position:0% + + + + align:start position:0% + +yes + + align:start position:0% + + + + align:start position:0% + +the most important interaction anyway + + align:start position:0% +the most important interaction anyway + + + align:start position:0% +the most important interaction anyway +that would that mean that there's no + + align:start position:0% + + + + align:start position:0% + +yeah it's an interesting question and + + align:start position:0% +yeah it's an interesting question and + + + align:start position:0% +yeah it's an interesting question and +this is something that we we were + + align:start position:0% +this is something that we we were + + + align:start position:0% +this is something that we we were +concerned with all the results I'm + + align:start position:0% +concerned with all the results I'm + + + align:start position:0% +concerned with all the results I'm +showing you today assume that you've + + align:start position:0% +showing you today assume that you've + + + align:start position:0% +showing you today assume that you've +randomized the ordering of the factors + + align:start position:0% +randomized the ordering of the factors + + + align:start position:0% +randomized the ordering of the factors +and that you've randomized the starting + + align:start position:0% +and that you've randomized the starting + + + align:start position:0% +and that you've randomized the starting +point and so far what our investigations + + align:start position:0% +point and so far what our investigations + + + align:start position:0% +point and so far what our investigations +show is that the ordering of the factors + + align:start position:0% +show is that the ordering of the factors + + + align:start position:0% +show is that the ordering of the factors +doesn't matter much but the starting + + align:start position:0% +doesn't matter much but the starting + + + align:start position:0% +doesn't matter much but the starting +points do so I would say whether or not + + align:start position:0% +points do so I would say whether or not + + + align:start position:0% +points do so I would say whether or not +you order the factors from next to the + + align:start position:0% +you order the factors from next to the + + + align:start position:0% +you order the factors from next to the +next it's a minor improvement not big + + align:start position:0% +next it's a minor improvement not big + + + align:start position:0% +next it's a minor improvement not big +but if you select a very promising + + align:start position:0% +but if you select a very promising + + + align:start position:0% +but if you select a very promising +starting point that is you know go with + + align:start position:0% +starting point that is you know go with + + + align:start position:0% +starting point that is you know go with +something that is likely to be very + + align:start position:0% +something that is likely to be very + + + align:start position:0% +something that is likely to be very +robust high performance that makes a big + + align:start position:0% +robust high performance that makes a big + + + align:start position:0% +robust high performance that makes a big +difference and it wasn't obvious to us + + align:start position:0% +difference and it wasn't obvious to us + + + align:start position:0% +difference and it wasn't obvious to us +start I thought probably what you said + + align:start position:0% +start I thought probably what you said + + + align:start position:0% +start I thought probably what you said +was was true it turned out to be the + + align:start position:0% +was was true it turned out to be the + + + align:start position:0% +was was true it turned out to be the +other way around so the dynamics of this + + align:start position:0% +other way around so the dynamics of this + + + align:start position:0% +other way around so the dynamics of this +process of experimentation are such that + + align:start position:0% +process of experimentation are such that + + + align:start position:0% +process of experimentation are such that +it turns out the the probability of + + align:start position:0% +it turns out the the probability of + + + align:start position:0% +it turns out the the probability of +exploiting interactions as you go gets + + align:start position:0% +exploiting interactions as you go gets + + + align:start position:0% +exploiting interactions as you go gets +higher and higher throughout the course + + align:start position:0% +higher and higher throughout the course + + + align:start position:0% +higher and higher throughout the course +of the experiment so it's true that if + + align:start position:0% +of the experiment so it's true that if + + + align:start position:0% +of the experiment so it's true that if +you knew where the interactions lie + + align:start position:0% +you knew where the interactions lie + + + align:start position:0% +you knew where the interactions lie +you'd like to toggle them for the last + + align:start position:0% +you'd like to toggle them for the last + + + align:start position:0% +you'd like to toggle them for the last +time as late as possible but I guess I I + + align:start position:0% +time as late as possible but I guess I I + + + align:start position:0% +time as late as possible but I guess I I +don't really believe that people would + + align:start position:0% +don't really believe that people would + + + align:start position:0% +don't really believe that people would +be able to identify which two + + align:start position:0% +be able to identify which two + + + align:start position:0% +be able to identify which two +interactions are going to participate + + align:start position:0% + + + + align:start position:0% + +so I ruled that out and didn't study it + + align:start position:0% +so I ruled that out and didn't study it + + + align:start position:0% +so I ruled that out and didn't study it +much but the point is that even if you + + align:start position:0% +much but the point is that even if you + + + align:start position:0% +much but the point is that even if you +didn't know where they lie the benefits + + align:start position:0% +didn't know where they lie the benefits + + + align:start position:0% +didn't know where they lie the benefits +continue to accrue almost linearly even + + align:start position:0% +continue to accrue almost linearly even + + + align:start position:0% +continue to accrue almost linearly even +though you're explaining fewer and fewer + + align:start position:0% +though you're explaining fewer and fewer + + + align:start position:0% +though you're explaining fewer and fewer +new interactions as you go you see the + + align:start position:0% +new interactions as you go you see the + + + align:start position:0% +new interactions as you go you see the +the white ones left to benefit are are + + align:start position:0% +the white ones left to benefit are are + + + align:start position:0% +the white ones left to benefit are are +diminishing over time but because their + + align:start position:0% +diminishing over time but because their + + + align:start position:0% +diminishing over time but because their +likelihood of coming in your favor is + + align:start position:0% +likelihood of coming in your favor is + + + align:start position:0% +likelihood of coming in your favor is +increasing you go up almost linearly and + + align:start position:0% +increasing you go up almost linearly and + + + align:start position:0% +increasing you go up almost linearly and +you get + + align:start position:0% +you get + + + align:start position:0% +you get +almost to the end 80% you get almost to + + align:start position:0% +almost to the end 80% you get almost to + + + align:start position:0% +almost to the end 80% you get almost to +one well pretty close and what's + + align:start position:0% +one well pretty close and what's + + + align:start position:0% +one well pretty close and what's +interesting to us about this is take the + + align:start position:0% +interesting to us about this is take the + + + align:start position:0% +interesting to us about this is take the +case of seven factors you the adaptive + + align:start position:0% +case of seven factors you the adaptive + + + align:start position:0% +case of seven factors you the adaptive +one factor at a time assuming two levels + + align:start position:0% +one factor at a time assuming two levels + + + align:start position:0% +one factor at a time assuming two levels +that takes eight experiments the full + + align:start position:0% +that takes eight experiments the full + + + align:start position:0% +that takes eight experiments the full +factorial takes 128 so you've looked at + + align:start position:0% +factorial takes 128 so you've looked at + + + align:start position:0% +factorial takes 128 so you've looked at +a very small fraction of the overall + + align:start position:0% +a very small fraction of the overall + + + align:start position:0% +a very small fraction of the overall +space and you've gotten 80% of the way + + align:start position:0% +space and you've gotten 80% of the way + + + align:start position:0% +space and you've gotten 80% of the way +toward the best possible outcome in the + + align:start position:0% +toward the best possible outcome in the + + + align:start position:0% +toward the best possible outcome in the +space that sauce is interesting and then + + align:start position:0% +space that sauce is interesting and then + + + align:start position:0% +space that sauce is interesting and then +if I want to compare the the use of + + align:start position:0% +if I want to compare the the use of + + + align:start position:0% +if I want to compare the the use of +resolution three designs and adaptive + + align:start position:0% +resolution three designs and adaptive + + + align:start position:0% +resolution three designs and adaptive +designs we have expressions for each and + + align:start position:0% +designs we have expressions for each and + + + align:start position:0% +designs we have expressions for each and +then to make the comparison straight one + + align:start position:0% +then to make the comparison straight one + + + align:start position:0% +then to make the comparison straight one +against the other we do the following + + align:start position:0% +against the other we do the following + + + align:start position:0% +against the other we do the following +just hold them up against one another + + align:start position:0% +just hold them up against one another + + + align:start position:0% +just hold them up against one another +look at let's we see that experimental + + align:start position:0% +look at let's we see that experimental + + + align:start position:0% +look at let's we see that experimental +error is plotted parametrically so let's + + align:start position:0% +error is plotted parametrically so let's + + + align:start position:0% +error is plotted parametrically so let's +let's look at just the crossing point + + align:start position:0% +let's look at just the crossing point + + + align:start position:0% +let's look at just the crossing point +when experimental error is about the + + align:start position:0% +when experimental error is about the + + + align:start position:0% +when experimental error is about the +size of main effects they cross at the + + align:start position:0% +size of main effects they cross at the + + + align:start position:0% +size of main effects they cross at the +point where interactions are about a + + align:start position:0% +point where interactions are about a + + + align:start position:0% +point where interactions are about a +quarter of main effects the reason we + + align:start position:0% +quarter of main effects the reason we + + + align:start position:0% +quarter of main effects the reason we +think that one is interesting is that in + + align:start position:0% +think that one is interesting is that in + + + align:start position:0% +think that one is interesting is that in +our I alluded to earlier the idea that + + align:start position:0% +our I alluded to earlier the idea that + + + align:start position:0% +our I alluded to earlier the idea that +we are doing these studies big studies + + align:start position:0% +we are doing these studies big studies + + + align:start position:0% +we are doing these studies big studies +of complex systems and regularities and + + align:start position:0% +of complex systems and regularities and + + + align:start position:0% +of complex systems and regularities and +one of the things we found is that + + align:start position:0% +one of the things we found is that + + + align:start position:0% +one of the things we found is that +interactions being about a quarter the + + align:start position:0% +interactions being about a quarter the + + + align:start position:0% +interactions being about a quarter the +size of main effects that's pretty + + align:start position:0% +size of main effects that's pretty + + + align:start position:0% +size of main effects that's pretty +typical that's a typical amount so if + + align:start position:0% +typical that's a typical amount so if + + + align:start position:0% +typical that's a typical amount so if +you go into a factory and you get your + + align:start position:0% +you go into a factory and you get your + + + align:start position:0% +you go into a factory and you get your +engineers to list a number of factors + + align:start position:0% +engineers to list a number of factors + + + align:start position:0% +engineers to list a number of factors +they're interested in studying and then + + align:start position:0% +they're interested in studying and then + + + align:start position:0% +they're interested in studying and then +you run a big experiment and and study + + align:start position:0% +you run a big experiment and and study + + + align:start position:0% +you run a big experiment and and study +some of the interactions to you will + + align:start position:0% +some of the interactions to you will + + + align:start position:0% +some of the interactions to you will +generally find they're about a quarter + + align:start position:0% +generally find they're about a quarter + + + align:start position:0% +generally find they're about a quarter +of the size of the main effect it's just + + align:start position:0% +of the size of the main effect it's just + + + align:start position:0% +of the size of the main effect it's just +a reasonably reliable regularity and so + + align:start position:0% +a reasonably reliable regularity and so + + + align:start position:0% +a reasonably reliable regularity and so +we think that's typical and the way I + + align:start position:0% +we think that's typical and the way I + + + align:start position:0% +we think that's typical and the way I +would interpret the graph is that if + + align:start position:0% +would interpret the graph is that if + + + align:start position:0% +would interpret the graph is that if +your system is pretty typical in this + + align:start position:0% +your system is pretty typical in this + + + align:start position:0% +your system is pretty typical in this +regard strength of interactions you + + align:start position:0% +regard strength of interactions you + + + align:start position:0% +regard strength of interactions you +should be doing the adaptive experiments + + align:start position:0% +should be doing the adaptive experiments + + + align:start position:0% +should be doing the adaptive experiments +whatever error is less than main effects + + align:start position:0% +whatever error is less than main effects + + + align:start position:0% + +so Cuthbert Daniel's criterion for + + align:start position:0% +so Cuthbert Daniel's criterion for + + + align:start position:0% +so Cuthbert Daniel's criterion for +demarcation was err should be about a + + align:start position:0% +demarcation was err should be about a + + + align:start position:0% +demarcation was err should be about a +third or a quarter of main effects and + + align:start position:0% +third or a quarter of main effects and + + + align:start position:0% +third or a quarter of main effects and +we're saying now it's actually more like + + align:start position:0% +we're saying now it's actually more like + + + align:start position:0% +we're saying now it's actually more like +the size of Maine effects not a third or + + align:start position:0% +the size of Maine effects not a third or + + + align:start position:0% +the size of Maine effects not a third or +a quarter that's assuming importantly + + align:start position:0% +a quarter that's assuming importantly + + + align:start position:0% +a quarter that's assuming importantly +that your main goal is just getting + + align:start position:0% +that your main goal is just getting + + + align:start position:0% +that your main goal is just getting +improvement playing exactly where they + + align:start position:0% +improvement playing exactly where they + + + align:start position:0% +improvement playing exactly where they +came from or estimating effects + + align:start position:0% +came from or estimating effects + + + align:start position:0% +came from or estimating effects +accurately now our primary reason for + + align:start position:0% +accurately now our primary reason for + + + align:start position:0% +accurately now our primary reason for +going into all this in the first place + + align:start position:0% +going into all this in the first place + + + align:start position:0% +going into all this in the first place +was to deal with robust design in the + + align:start position:0% +was to deal with robust design in the + + + align:start position:0% +was to deal with robust design in the +end and so we we attempted lots of + + align:start position:0% +end and so we we attempted lots of + + + align:start position:0% +end and so we we attempted lots of +different ways of combining the noise + + align:start position:0% +different ways of combining the noise + + + align:start position:0% +different ways of combining the noise +factors with the control factors and so + + align:start position:0% +factors with the control factors and so + + + align:start position:0% +factors with the control factors and so +far the simplest thing turned out to be + + align:start position:0% +far the simplest thing turned out to be + + + align:start position:0% +far the simplest thing turned out to be +the best and that is what you see here + + align:start position:0% +the best and that is what you see here + + + align:start position:0% +the best and that is what you see here +in this cuboidal representation is our + + align:start position:0% +in this cuboidal representation is our + + + align:start position:0% +in this cuboidal representation is our +controllable factors a B and C when our + + align:start position:0% +controllable factors a B and C when our + + + align:start position:0% +controllable factors a B and C when our +noise factors little a B and C are being + + align:start position:0% +noise factors little a B and C are being + + + align:start position:0% +noise factors little a B and C are being +crossed in effect we take the adaptive + + align:start position:0% +crossed in effect we take the adaptive + + + align:start position:0% +crossed in effect we take the adaptive +procedure we run a factorial design in + + align:start position:0% +procedure we run a factorial design in + + + align:start position:0% +procedure we run a factorial design in +the noise then change one of the control + + align:start position:0% +the noise then change one of the control + + + align:start position:0% +the noise then change one of the control +factors just one and run again the exact + + align:start position:0% +factors just one and run again the exact + + + align:start position:0% +factors just one and run again the exact +same design and then what we do is we + + align:start position:0% +same design and then what we do is we + + + align:start position:0% +same design and then what we do is we +select our level in this case of a on + + align:start position:0% +select our level in this case of a on + + + align:start position:0% +select our level in this case of a on +the basis of our preference for this set + + align:start position:0% +the basis of our preference for this set + + + align:start position:0% +the basis of our preference for this set +of observations versus this set if we + + align:start position:0% +of observations versus this set if we + + + align:start position:0% +of observations versus this set if we +like this set because for example it has + + align:start position:0% +like this set because for example it has + + + align:start position:0% +like this set because for example it has +lower variation then we select it we + + align:start position:0% +lower variation then we select it we + + + align:start position:0% +lower variation then we select it we +select a is positive and then we just + + align:start position:0% +select a is positive and then we just + + + align:start position:0% +select a is positive and then we just +continue to wind our way through the + + align:start position:0% +continue to wind our way through the + + + align:start position:0% +continue to wind our way through the +space reversing changes that we don't + + align:start position:0% +space reversing changes that we don't + + + align:start position:0% +space reversing changes that we don't +like and adopting ones that we do and we + + align:start position:0% +like and adopting ones that we do and we + + + align:start position:0% +like and adopting ones that we do and we +we studied this this says except it + + align:start position:0% +we studied this this says except it + + + align:start position:0% +we studied this this says except it +actually appeared in a semi journal I've + + align:start position:0% +actually appeared in a semi journal I've + + + align:start position:0% +actually appeared in a semi journal I've +got to change that so we began to + + align:start position:0% +got to change that so we began to + + + align:start position:0% +got to change that so we began to +validate this approach by applying it + + align:start position:0% +validate this approach by applying it + + + align:start position:0% +validate this approach by applying it +through a number of different systems + + align:start position:0% +through a number of different systems + + + align:start position:0% +through a number of different systems +one that might be of interest to you is + + align:start position:0% +one that might be of interest to you is + + + align:start position:0% +one that might be of interest to you is +sheet metal spinning so in this process + + align:start position:0% +sheet metal spinning so in this process + + + align:start position:0% +sheet metal spinning so in this process +you go into your factory you take sheet + + align:start position:0% +you go into your factory you take sheet + + + align:start position:0% +you go into your factory you take sheet +metal articles and you turn them into + + align:start position:0% +metal articles and you turn them into + + + align:start position:0% +metal articles and you turn them into +manufactured goods surfaces of + + align:start position:0% +manufactured goods surfaces of + + + align:start position:0% +manufactured goods surfaces of +revolution cups and bells and whatever + + align:start position:0% +revolution cups and bells and whatever + + + align:start position:0% +revolution cups and bells and whatever +you need by taking the circular blank + + align:start position:0% +you need by taking the circular blank + + + align:start position:0% +you need by taking the circular blank +pressing it up again + + align:start position:0% +pressing it up again + + + align:start position:0% +pressing it up again +a mandrel repetitively until you get the + + align:start position:0% +a mandrel repetitively until you get the + + + align:start position:0% +a mandrel repetitively until you get the +deformation that you want and you might + + align:start position:0% +deformation that you want and you might + + + align:start position:0% +deformation that you want and you might +be interested for example in consistency + + align:start position:0% +be interested for example in consistency + + + align:start position:0% +be interested for example in consistency +of the geometry and you might be + + align:start position:0% +of the geometry and you might be + + + align:start position:0% +of the geometry and you might be +interested in how a number of different + + align:start position:0% +interested in how a number of different + + + align:start position:0% +interested in how a number of different +parameters affect that consistency of + + align:start position:0% +parameters affect that consistency of + + + align:start position:0% +parameters affect that consistency of +the geometry such as what material you + + align:start position:0% +the geometry such as what material you + + + align:start position:0% +the geometry such as what material you +chose the shape of the mandrel the shape + + align:start position:0% +chose the shape of the mandrel the shape + + + align:start position:0% +chose the shape of the mandrel the shape +of the the path which you which you use + + align:start position:0% +of the the path which you which you use + + + align:start position:0% +of the the path which you which you use +the number of times and with the force + + align:start position:0% +the number of times and with the force + + + align:start position:0% +the number of times and with the force +you apply and this was studied by a + + align:start position:0% +you apply and this was studied by a + + + align:start position:0% +you apply and this was studied by a +group in Germany and we used their + + align:start position:0% +group in Germany and we used their + + + align:start position:0% +group in Germany and we used their +results to simulate the process of + + align:start position:0% +results to simulate the process of + + + align:start position:0% +results to simulate the process of +running these adaptive experiments and + + align:start position:0% +running these adaptive experiments and + + + align:start position:0% +running these adaptive experiments and +running an alternative across their a + + align:start position:0% +running an alternative across their a + + + align:start position:0% +running an alternative across their a +design on these systems and we found + + align:start position:0% +design on these systems and we found + + + align:start position:0% +design on these systems and we found +that that the Taguchi style cross array + + align:start position:0% +that that the Taguchi style cross array + + + align:start position:0% +that that the Taguchi style cross array +made indeed improvements in signal noise + + align:start position:0% +made indeed improvements in signal noise + + + align:start position:0% +made indeed improvements in signal noise +ratio of the system but our adaptive + + align:start position:0% +ratio of the system but our adaptive + + + align:start position:0% +ratio of the system but our adaptive +procedures were doing a little better + + align:start position:0% +procedures were doing a little better + + + align:start position:0% +procedures were doing a little better +until you got to some crossing point + + align:start position:0% +until you got to some crossing point + + + align:start position:0% +until you got to some crossing point +experimental error up here of you know + + align:start position:0% +experimental error up here of you know + + + align:start position:0% +experimental error up here of you know +two millimeters squared of this quality + + align:start position:0% +two millimeters squared of this quality + + + align:start position:0% +two millimeters squared of this quality +measure and this is where we found + + align:start position:0% +measure and this is where we found + + + align:start position:0% +measure and this is where we found +another result the one that I alluded to + + align:start position:0% +another result the one that I alluded to + + + align:start position:0% +another result the one that I alluded to +earlier that if you gave the engineers + + align:start position:0% +earlier that if you gave the engineers + + + align:start position:0% +earlier that if you gave the engineers +the benefit of doubt and suggested that + + align:start position:0% +the benefit of doubt and suggested that + + + align:start position:0% +the benefit of doubt and suggested that +they didn't choose their starting points + + align:start position:0% +they didn't choose their starting points + + + align:start position:0% +they didn't choose their starting points +at random but instead choose inform + + align:start position:0% +at random but instead choose inform + + + align:start position:0% +at random but instead choose inform +starting points and let me define what I + + align:start position:0% +starting points and let me define what I + + + align:start position:0% +starting points and let me define what I +mean by that lets you give you have a + + align:start position:0% +mean by that lets you give you have a + + + align:start position:0% +mean by that lets you give you have a +number of factors there are two levels a + + align:start position:0% +number of factors there are two levels a + + + align:start position:0% +number of factors there are two levels a +random starting point is just flipping + + align:start position:0% +random starting point is just flipping + + + align:start position:0% +random starting point is just flipping +coins you choose each one but let's say + + align:start position:0% +coins you choose each one but let's say + + + align:start position:0% +coins you choose each one but let's say +that somehow the engineers are able to + + align:start position:0% +that somehow the engineers are able to + + + align:start position:0% +that somehow the engineers are able to +do better than 50 percent odds of + + align:start position:0% +do better than 50 percent odds of + + + align:start position:0% +do better than 50 percent odds of +getting the best setting for each factor + + align:start position:0% +getting the best setting for each factor + + + align:start position:0% +getting the best setting for each factor +but instead have 75 percent chance of + + align:start position:0% +but instead have 75 percent chance of + + + align:start position:0% +but instead have 75 percent chance of +defining the superior level of each + + align:start position:0% +defining the superior level of each + + + align:start position:0% +defining the superior level of each +factor in that case in the end they + + align:start position:0% +factor in that case in the end they + + + align:start position:0% +factor in that case in the end they +would get this result substantially + + align:start position:0% +would get this result substantially + + + align:start position:0% +would get this result substantially +higher than either of the other two + + align:start position:0% +higher than either of the other two + + + align:start position:0% +higher than either of the other two +alternatives and they'll never cross no + + align:start position:0% +alternatives and they'll never cross no + + + align:start position:0% +alternatives and they'll never cross no +matter how much error there is + + align:start position:0% +matter how much error there is + + + align:start position:0% +matter how much error there is +yes + + align:start position:0% + + + + align:start position:0% + +yeah so smaller the better is the the + + align:start position:0% +yeah so smaller the better is the the + + + align:start position:0% +yeah so smaller the better is the the +parameter of interest was meant to be + + align:start position:0% +parameter of interest was meant to be + + + align:start position:0% +parameter of interest was meant to be +smaller is better but then when you + + align:start position:0% +smaller is better but then when you + + + align:start position:0% +smaller is better but then when you +compute a signal to noise ratio larger + + align:start position:0% +compute a signal to noise ratio larger + + + align:start position:0% +compute a signal to noise ratio larger +is better so the underlying parameter + + align:start position:0% +is better so the underlying parameter + + + align:start position:0% +is better so the underlying parameter +called a 20 in this case smaller was + + align:start position:0% +called a 20 in this case smaller was + + + align:start position:0% +called a 20 in this case smaller was +better but in taguchi's methodology you + + align:start position:0% +better but in taguchi's methodology you + + + align:start position:0% +better but in taguchi's methodology you +then take that parameter and it's + + align:start position:0% +then take that parameter and it's + + + align:start position:0% +then take that parameter and it's +variation and transform it to get a + + align:start position:0% +variation and transform it to get a + + + align:start position:0% +variation and transform it to get a +signal noise ratio and what signal noise + + align:start position:0% +signal noise ratio and what signal noise + + + align:start position:0% +signal noise ratio and what signal noise +ratio larger is always better + + align:start position:0% +ratio larger is always better + + + align:start position:0% +ratio larger is always better +so I appreciate why that's confusing + + align:start position:0% + + + + align:start position:0% + +this one I add I include it in the paper + + align:start position:0% +this one I add I include it in the paper + + + align:start position:0% +this one I add I include it in the paper +and I include it for you because in some + + align:start position:0% +and I include it for you because in some + + + align:start position:0% +and I include it for you because in some +cases you'll you'll feel skeptical about + + align:start position:0% +cases you'll you'll feel skeptical about + + + align:start position:0% +cases you'll you'll feel skeptical about +these results right because they still + + align:start position:0% +these results right because they still + + + align:start position:0% +these results right because they still +are pretty current to ative and you + + align:start position:0% +are pretty current to ative and you + + + align:start position:0% +are pretty current to ative and you +might need to demonstrate them to + + align:start position:0% +might need to demonstrate them to + + + align:start position:0% +might need to demonstrate them to +yourself and the paper airplane allows + + align:start position:0% +yourself and the paper airplane allows + + + align:start position:0% +yourself and the paper airplane allows +you to do that so Steve up and jerk came + + align:start position:0% +you to do that so Steve up and jerk came + + + align:start position:0% +you to do that so Steve up and jerk came +up with this template for demonstrating + + align:start position:0% +up with this template for demonstrating + + + align:start position:0% +up with this template for demonstrating +some of the methods here in robust + + align:start position:0% +some of the methods here in robust + + + align:start position:0% +some of the methods here in robust +design and design of experiments and the + + align:start position:0% +design and design of experiments and the + + + align:start position:0% +design and design of experiments and the +template allows you to fold a variety of + + align:start position:0% +template allows you to fold a variety of + + + align:start position:0% +template allows you to fold a variety of +different paper airplanes in this case + + align:start position:0% +different paper airplanes in this case + + + align:start position:0% +different paper airplanes in this case +it's 3 to the 4 or 81 different paper + + align:start position:0% +it's 3 to the 4 or 81 different paper + + + align:start position:0% +it's 3 to the 4 or 81 different paper +airplanes and we ran an experiment in + + align:start position:0% +airplanes and we ran an experiment in + + + align:start position:0% +airplanes and we ran an experiment in +which we had created different noise + + align:start position:0% +which we had created different noise + + + align:start position:0% +which we had created different noise +conditions for the flights and you could + + align:start position:0% +conditions for the flights and you could + + + align:start position:0% +conditions for the flights and you could +replicate our results actually throw + + align:start position:0% +replicate our results actually throw + + + align:start position:0% +replicate our results actually throw +these airplanes and do it adaptively one + + align:start position:0% +these airplanes and do it adaptively one + + + align:start position:0% +these airplanes and do it adaptively one +factor at a time and I think you'll find + + align:start position:0% +factor at a time and I think you'll find + + + align:start position:0% +factor at a time and I think you'll find +the same results as we did that if you + + align:start position:0% +the same results as we did that if you + + + align:start position:0% +the same results as we did that if you +do the l9 Taguchi array or else that's a + + align:start position:0% +do the l9 Taguchi array or else that's a + + + align:start position:0% +do the l9 Taguchi array or else that's a +placket Behrman design by another name + + align:start position:0% +placket Behrman design by another name + + + align:start position:0% +placket Behrman design by another name +cross it with a 2 or 3 minus 1 noise + + align:start position:0% +cross it with a 2 or 3 minus 1 noise + + + align:start position:0% +cross it with a 2 or 3 minus 1 noise +array you'd get these kind of + + align:start position:0% +array you'd get these kind of + + + align:start position:0% +array you'd get these kind of +improvements in signal noise ratio but + + align:start position:0% +improvements in signal noise ratio but + + + align:start position:0% +improvements in signal noise ratio but +if you run it adapted ly with random + + align:start position:0% +if you run it adapted ly with random + + + align:start position:0% +if you run it adapted ly with random +starting points you'll get better + + align:start position:0% +starting points you'll get better + + + align:start position:0% +starting points you'll get better +results and if you use an informed + + align:start position:0% +results and if you use an informed + + + align:start position:0% +results and if you use an informed +starting point such as you know looking + + align:start position:0% +starting point such as you know looking + + + align:start position:0% +starting point such as you know looking +at a plane that has about the right + + align:start position:0% +at a plane that has about the right + + + align:start position:0% +at a plane that has about the right +aspect ratio and and maybe you know + + align:start position:0% +aspect ratio and and maybe you know + + + align:start position:0% +aspect ratio and and maybe you know +right ahead that folding up the little + + align:start position:0% +right ahead that folding up the little + + + align:start position:0% +right ahead that folding up the little +winglets out here is probably better you + + align:start position:0% +winglets out here is probably better you + + + align:start position:0% +winglets out here is probably better you +know for lateral stability if you make + + align:start position:0% +know for lateral stability if you make + + + align:start position:0% +know for lateral stability if you make +such judgments you'll get even better + + align:start position:0% +such judgments you'll get even better + + + align:start position:0% +such judgments you'll get even better +results + + align:start position:0% +results + + + align:start position:0% +results +and so that's what the paper airplane + + align:start position:0% +and so that's what the paper airplane + + + align:start position:0% +and so that's what the paper airplane +studies tells us so we did for such + + align:start position:0% +studies tells us so we did for such + + + align:start position:0% +studies tells us so we did for such +studies and here's an here's a point + + align:start position:0% +studies and here's an here's a point + + + align:start position:0% +studies and here's an here's a point +that I find interesting okay first of + + align:start position:0% +that I find interesting okay first of + + + align:start position:0% +that I find interesting okay first of +all if you if you're at lower error + + align:start position:0% +all if you if you're at lower error + + + align:start position:0% +all if you if you're at lower error +states what you find is that on average + + align:start position:0% +states what you find is that on average + + + align:start position:0% +states what you find is that on average +the the random approach you know + + align:start position:0% +the the random approach you know + + + align:start position:0% +the the random approach you know +starting at random starting points works + + align:start position:0% +starting at random starting points works + + + align:start position:0% +starting at random starting points works +better than the fractional factorial in + + align:start position:0% +better than the fractional factorial in + + + align:start position:0% +better than the fractional factorial in +form starting points are better than + + align:start position:0% +form starting points are better than + + + align:start position:0% +form starting points are better than +that if you raise the error high enough + + align:start position:0% +that if you raise the error high enough + + + align:start position:0% +that if you raise the error high enough +things turn around and the factorial + + align:start position:0% +things turn around and the factorial + + + align:start position:0% +things turn around and the factorial +design is a little better than the + + align:start position:0% +design is a little better than the + + + align:start position:0% +design is a little better than the +adaptive approach unless you use the + + align:start position:0% +adaptive approach unless you use the + + + align:start position:0% +adaptive approach unless you use the +informed starting point but what I think + + align:start position:0% +informed starting point but what I think + + + align:start position:0% +informed starting point but what I think +is further interesting is that if you + + align:start position:0% +is further interesting is that if you + + + align:start position:0% +is further interesting is that if you +look at the inner quartile if you look + + align:start position:0% +look at the inner quartile if you look + + + align:start position:0% +look at the inner quartile if you look +at the range of results across cases the + + align:start position:0% +at the range of results across cases the + + + align:start position:0% +at the range of results across cases the +adaptive procedure even at high error to + + align:start position:0% +adaptive procedure even at high error to + + + align:start position:0% +adaptive procedure even at high error to +me that's a preferable range 51 to 87 + + align:start position:0% +me that's a preferable range 51 to 87 + + + align:start position:0% +me that's a preferable range 51 to 87 +verses 36 to 88 I think you you actually + + align:start position:0% +verses 36 to 88 I think you you actually + + + align:start position:0% +verses 36 to 88 I think you you actually +take less risk from case to case with + + align:start position:0% +take less risk from case to case with + + + align:start position:0% +take less risk from case to case with +the adaptive method now so the the the + + align:start position:0% +the adaptive method now so the the the + + + align:start position:0% +the adaptive method now so the the the +the factorial design is optimally suited + + align:start position:0% +the factorial design is optimally suited + + + align:start position:0% +the factorial design is optimally suited +to minimize the influence of + + align:start position:0% +to minimize the influence of + + + align:start position:0% +to minimize the influence of +experimental error on your outcomes but + + align:start position:0% +experimental error on your outcomes but + + + align:start position:0% +experimental error on your outcomes but +some of the uncertainties you face an + + align:start position:0% +some of the uncertainties you face an + + + align:start position:0% +some of the uncertainties you face an +experimentation aren't that kind they're + + align:start position:0% +experimentation aren't that kind they're + + + align:start position:0% +experimentation aren't that kind they're +not experimental error they're actually + + align:start position:0% +not experimental error they're actually + + + align:start position:0% +not experimental error they're actually +uncertainties about where the + + align:start position:0% +uncertainties about where the + + + align:start position:0% +uncertainties about where the +interactions lie + + align:start position:0% +interactions lie + + + align:start position:0% +interactions lie +and in fact fractional factorial designs + + align:start position:0% +and in fact fractional factorial designs + + + align:start position:0% +and in fact fractional factorial designs +are among the most sensitive designs to + + align:start position:0% +are among the most sensitive designs to + + + align:start position:0% +are among the most sensitive designs to +that particular uncertainty because when + + align:start position:0% +that particular uncertainty because when + + + align:start position:0% +that particular uncertainty because when +you make this confounding between main + + align:start position:0% +you make this confounding between main + + + align:start position:0% +you make this confounding between main +effects and interactions it's actually + + align:start position:0% +effects and interactions it's actually + + + align:start position:0% +effects and interactions it's actually +very harmful to your outcomes + + align:start position:0% + + + + align:start position:0% + +so those are the principal results that + + align:start position:0% +so those are the principal results that + + + align:start position:0% +so those are the principal results that +I meant to show you today there are a + + align:start position:0% +I meant to show you today there are a + + + align:start position:0% +I meant to show you today there are a +couple other things that have emerged + + align:start position:0% +couple other things that have emerged + + + align:start position:0% +couple other things that have emerged +more recently that I can talk about for + + align:start position:0% +more recently that I can talk about for + + + align:start position:0% +more recently that I can talk about for +example recently we've been interested + + align:start position:0% +example recently we've been interested + + + align:start position:0% +example recently we've been interested +in the idea producing ensembles now here + + align:start position:0% +in the idea producing ensembles now here + + + align:start position:0% +in the idea producing ensembles now here +the situation is that you might find + + align:start position:0% +the situation is that you might find + + + align:start position:0% +the situation is that you might find +that you have adequate budget to run a + + align:start position:0% +that you have adequate budget to run a + + + align:start position:0% +that you have adequate budget to run a +larger fractional factorial design let's + + align:start position:0% +larger fractional factorial design let's + + + align:start position:0% +larger fractional factorial design let's +say instead of a 2 to the 7 minus 4 you + + align:start position:0% +say instead of a 2 to the 7 minus 4 you + + + align:start position:0% +say instead of a 2 to the 7 minus 4 you +actually have a budget to run a much + + align:start position:0% +actually have a budget to run a much + + + align:start position:0% +actually have a budget to run a much +larger experiment 2 to 7 minus 2 so the + + align:start position:0% +larger experiment 2 to 7 minus 2 so the + + + align:start position:0% +larger experiment 2 to 7 minus 2 so the +counter-argument was from from some + + align:start position:0% +counter-argument was from from some + + + align:start position:0% +counter-argument was from from some +folks in industry was that they rarely + + align:start position:0% +folks in industry was that they rarely + + + align:start position:0% +folks in industry was that they rarely +ran resolution 3 designs they thought + + align:start position:0% +ran resolution 3 designs they thought + + + align:start position:0% +ran resolution 3 designs they thought +that that was too big a risk anyway they + + align:start position:0% +that that was too big a risk anyway they + + + align:start position:0% +that that was too big a risk anyway they +were tending to run larger experiments + + align:start position:0% +were tending to run larger experiments + + + align:start position:0% +were tending to run larger experiments +such as to the 7-2 higher resolution + + align:start position:0% +such as to the 7-2 higher resolution + + + align:start position:0% +such as to the 7-2 higher resolution +fractional factorial designs and they + + align:start position:0% +fractional factorial designs and they + + + align:start position:0% +fractional factorial designs and they +said so because of that I don't think we + + align:start position:0% +said so because of that I don't think we + + + align:start position:0% +said so because of that I don't think we +should do the adaptive effect and we + + align:start position:0% +should do the adaptive effect and we + + + align:start position:0% +should do the adaptive effect and we +were interested in that condition that + + align:start position:0% +were interested in that condition that + + + align:start position:0% +were interested in that condition that +issue it turns out that if you take the + + align:start position:0% +issue it turns out that if you take the + + + align:start position:0% +issue it turns out that if you take the +same budget that it takes to do to the 2 + + align:start position:0% +same budget that it takes to do to the 2 + + + align:start position:0% +same budget that it takes to do to the 2 +to 7 minus 2 you would be able to run + + align:start position:0% +to 7 minus 2 you would be able to run + + + align:start position:0% +to 7 minus 2 you would be able to run +for ofat now if you do that if you + + align:start position:0% +for ofat now if you do that if you + + + align:start position:0% +for ofat now if you do that if you +choose 4 different starting points and 4 + + align:start position:0% +choose 4 different starting points and 4 + + + align:start position:0% +choose 4 different starting points and 4 +different orderings of the factors and + + align:start position:0% +different orderings of the factors and + + + align:start position:0% +different orderings of the factors and +run for ofat and then take those results + + align:start position:0% +run for ofat and then take those results + + + align:start position:0% +run for ofat and then take those results +and make it ensemble of them and for + + align:start position:0% +and make it ensemble of them and for + + + align:start position:0% +and make it ensemble of them and for +example a simple thing you could do is + + align:start position:0% +example a simple thing you could do is + + + align:start position:0% +example a simple thing you could do is +just pick the best of the four again the + + align:start position:0% +just pick the best of the four again the + + + align:start position:0% +just pick the best of the four again the +ensemble would produce a better result + + align:start position:0% +ensemble would produce a better result + + + align:start position:0% +ensemble would produce a better result +than the fractional factorial design and + + align:start position:0% +than the fractional factorial design and + + + align:start position:0% +than the fractional factorial design and +then the interesting thing we find about + + align:start position:0% +then the interesting thing we find about + + + align:start position:0% +then the interesting thing we find about +it is remember before when you increase + + align:start position:0% +it is remember before when you increase + + + align:start position:0% +it is remember before when you increase +experimental error you expect the ofat + + align:start position:0% +experimental error you expect the ofat + + + align:start position:0% +experimental error you expect the ofat +to eventually degrade in performance and + + align:start position:0% +to eventually degrade in performance and + + + align:start position:0% +to eventually degrade in performance and +to cross with the fractional factorial + + align:start position:0% +to cross with the fractional factorial + + + align:start position:0% +to cross with the fractional factorial +so now the issue is how much + + align:start position:0% +so now the issue is how much + + + align:start position:0% +so now the issue is how much +experimental error can I endure before + + align:start position:0% +experimental error can I endure before + + + align:start position:0% +experimental error can I endure before +the adaptive experiment is no longer + + align:start position:0% +the adaptive experiment is no longer + + + align:start position:0% +the adaptive experiment is no longer +recommended with the ensemble method is + + align:start position:0% +recommended with the ensemble method is + + + align:start position:0% +recommended with the ensemble method is +actually the opposite way as you + + align:start position:0% +actually the opposite way as you + + + align:start position:0% +actually the opposite way as you +increase experimental error eventually + + align:start position:0% +increase experimental error eventually + + + align:start position:0% +increase experimental error eventually +the ensemble the distance between the + + align:start position:0% +the ensemble the distance between the + + + align:start position:0% +the ensemble the distance between the +ensemble and the fractional + + align:start position:0% +ensemble and the fractional + + + align:start position:0% +ensemble and the fractional +factorial increases so the ensemble + + align:start position:0% +factorial increases so the ensemble + + + align:start position:0% +factorial increases so the ensemble +method by itself is providing a kind of + + align:start position:0% +method by itself is providing a kind of + + + align:start position:0% +method by itself is providing a kind of +robustness to experimental error and so + + align:start position:0% + + + + align:start position:0% + +we've been able to address another one + + align:start position:0% +we've been able to address another one + + + align:start position:0% +we've been able to address another one +of the counter points to the adaptive + + align:start position:0% +of the counter points to the adaptive + + + align:start position:0% +of the counter points to the adaptive +experimentation idea that in those cases + + align:start position:0% +experimentation idea that in those cases + + + align:start position:0% +experimentation idea that in those cases +where experimental budgets are higher + + align:start position:0% +where experimental budgets are higher + + + align:start position:0% +where experimental budgets are higher +you might still want to run these the + + align:start position:0% +you might still want to run these the + + + align:start position:0% +you might still want to run these the +other benefit of the ensembles that + + align:start position:0% +other benefit of the ensembles that + + + align:start position:0% +other benefit of the ensembles that +we've been able to show in another paper + + align:start position:0% +we've been able to show in another paper + + + align:start position:0% +we've been able to show in another paper +I didn't put some slides in but I want + + align:start position:0% +I didn't put some slides in but I want + + + align:start position:0% +I didn't put some slides in but I want +to tell you a little bit about it unless + + align:start position:0% +to tell you a little bit about it unless + + + align:start position:0% +to tell you a little bit about it unless +you have a question maybe I'll take your + + align:start position:0% +you have a question maybe I'll take your + + + align:start position:0% +you have a question maybe I'll take your +question + + align:start position:0% + + + + align:start position:0% + +yeah that's right ya know so you make a + + align:start position:0% +yeah that's right ya know so you make a + + + align:start position:0% +yeah that's right ya know so you make a +good point for example we know in + + align:start position:0% +good point for example we know in + + + align:start position:0% +good point for example we know in +agriculture you want to run 64 different + + align:start position:0% +agriculture you want to run 64 different + + + align:start position:0% +agriculture you want to run 64 different +treatment conditions and it takes a + + align:start position:0% +treatment conditions and it takes a + + + align:start position:0% +treatment conditions and it takes a +season to get your results so you want + + align:start position:0% +season to get your results so you want + + + align:start position:0% +season to get your results so you want +to run them in parallel it's important + + align:start position:0% +to run them in parallel it's important + + + align:start position:0% +to run them in parallel it's important +to run experiments in parallel in + + align:start position:0% +to run experiments in parallel in + + + align:start position:0% +to run experiments in parallel in +agriculture and in agricultural + + align:start position:0% +agriculture and in agricultural + + + align:start position:0% +agriculture and in agricultural +equipment it's exactly the opposite so + + align:start position:0% +equipment it's exactly the opposite so + + + align:start position:0% +equipment it's exactly the opposite so +what happens is you're trying to develop + + align:start position:0% +what happens is you're trying to develop + + + align:start position:0% +what happens is you're trying to develop +the next generation of tractor and what + + align:start position:0% +the next generation of tractor and what + + + align:start position:0% +the next generation of tractor and what +they do is they take the last generation + + align:start position:0% +they do is they take the last generation + + + align:start position:0% +they do is they take the last generation +of tractor that they built and they use + + align:start position:0% +of tractor that they built and they use + + + align:start position:0% +of tractor that they built and they use +that as what they call a mule and the + + align:start position:0% +that as what they call a mule and the + + + align:start position:0% +that as what they call a mule and the +automotive industry uses the same term + + align:start position:0% +automotive industry uses the same term + + + align:start position:0% +automotive industry uses the same term +you know you're making the next Taurus + + align:start position:0% +you know you're making the next Taurus + + + align:start position:0% +you know you're making the next Taurus +you take the 2007 Taurus and you start + + align:start position:0% +you take the 2007 Taurus and you start + + + align:start position:0% +you take the 2007 Taurus and you start +using it + + align:start position:0% +using it + + + align:start position:0% +using it +putting additions on it new fuel + + align:start position:0% +putting additions on it new fuel + + + align:start position:0% +putting additions on it new fuel +injection new valve timing and so on you + + align:start position:0% +injection new valve timing and so on you + + + align:start position:0% +injection new valve timing and so on you +use that as a mule and when you're using + + align:start position:0% +use that as a mule and when you're using + + + align:start position:0% +use that as a mule and when you're using +articles like that in that style and you + + align:start position:0% +articles like that in that style and you + + + align:start position:0% +articles like that in that style and you +have a limited number of them actually + + align:start position:0% +have a limited number of them actually + + + align:start position:0% +have a limited number of them actually +your experiments are necessarily + + align:start position:0% +your experiments are necessarily + + + align:start position:0% +your experiments are necessarily +sequential whereas in agriculture + + align:start position:0% +sequential whereas in agriculture + + + align:start position:0% +sequential whereas in agriculture +they're necessarily parallel so I + + align:start position:0% +they're necessarily parallel so I + + + align:start position:0% +they're necessarily parallel so I +actually agree with you when you're in + + align:start position:0% +actually agree with you when you're in + + + align:start position:0% +actually agree with you when you're in +an engineering scenario and and your + + align:start position:0% +an engineering scenario and and your + + + align:start position:0% +an engineering scenario and and your +experiments are necessarily parallel it + + align:start position:0% +experiments are necessarily parallel it + + + align:start position:0% +experiments are necessarily parallel it +sometimes happens in say lithography you + + align:start position:0% +sometimes happens in say lithography you + + + align:start position:0% +sometimes happens in say lithography you +know you're gonna you're gonna you're + + align:start position:0% +know you're gonna you're gonna you're + + + align:start position:0% +know you're gonna you're gonna you're +gonna have to etch all these things all + + align:start position:0% +gonna have to etch all these things all + + + align:start position:0% +gonna have to etch all these things all +at the same time in a batch yeah that's + + align:start position:0% +at the same time in a batch yeah that's + + + align:start position:0% +at the same time in a batch yeah that's +that's a reason to do it the other way + + align:start position:0% +that's a reason to do it the other way + + + align:start position:0% +that's a reason to do it the other way +but I think more often than not we're + + align:start position:0% +but I think more often than not we're + + + align:start position:0% +but I think more often than not we're +doing our experiments necessarily + + align:start position:0% +doing our experiments necessarily + + + align:start position:0% +doing our experiments necessarily +sequentially or or maybe it's okay to do + + align:start position:0% +sequentially or or maybe it's okay to do + + + align:start position:0% +sequentially or or maybe it's okay to do +it sequentially another factor since you + + align:start position:0% +it sequentially another factor since you + + + align:start position:0% +it sequentially another factor since you +asked is the possibility of time trends + + align:start position:0% +asked is the possibility of time trends + + + align:start position:0% +asked is the possibility of time trends +and indeed when you do adaptive + + align:start position:0% +and indeed when you do adaptive + + + align:start position:0% +and indeed when you do adaptive +experimentation you are necessarily + + align:start position:0% +experimentation you are necessarily + + + align:start position:0% +experimentation you are necessarily +making restrictions on randomization + + align:start position:0% +making restrictions on randomization + + + align:start position:0% +making restrictions on randomization +right so let's say that you're your + + align:start position:0% +right so let's say that you're your + + + align:start position:0% +right so let's say that you're your +measuring apparatus is drifting over + + align:start position:0% +measuring apparatus is drifting over + + + align:start position:0% +measuring apparatus is drifting over +time let's say it's drifting + + align:start position:0% +time let's say it's drifting + + + align:start position:0% +time let's say it's drifting +toward making all your results look + + align:start position:0% +toward making all your results look + + + align:start position:0% +toward making all your results look +worse you know + + align:start position:0% +worse you know + + + align:start position:0% +worse you know +that would give you somewhat of a bias + + align:start position:0% +that would give you somewhat of a bias + + + align:start position:0% +that would give you somewhat of a bias +toward your starting points as a port as + + align:start position:0% +toward your starting points as a port as + + + align:start position:0% +toward your starting points as a port as +opposed to all the leader changes as + + align:start position:0% +opposed to all the leader changes as + + + align:start position:0% +opposed to all the leader changes as +best we can tell actually the the + + align:start position:0% +best we can tell actually the the + + + align:start position:0% +best we can tell actually the the +adaptive procedure is not so + + align:start position:0% +adaptive procedure is not so + + + align:start position:0% +adaptive procedure is not so +hypersensitive to those time trends they + + align:start position:0% +hypersensitive to those time trends they + + + align:start position:0% +hypersensitive to those time trends they +reflect themselves some degree as if + + align:start position:0% +reflect themselves some degree as if + + + align:start position:0% +reflect themselves some degree as if +they were additional experimental error + + align:start position:0% +they were additional experimental error + + + align:start position:0% +they were additional experimental error +but if you randomized the starting + + align:start position:0% +but if you randomized the starting + + + align:start position:0% +but if you randomized the starting +points anyway and the order of factors I + + align:start position:0% +points anyway and the order of factors I + + + align:start position:0% +points anyway and the order of factors I +don't think it's worse than experimental + + align:start position:0% +don't think it's worse than experimental + + + align:start position:0% +don't think it's worse than experimental +error because you're not interested in + + align:start position:0% +error because you're not interested in + + + align:start position:0% +error because you're not interested in +factor effects in the end anyway that + + align:start position:0% +factor effects in the end anyway that + + + align:start position:0% +factor effects in the end anyway that +this is this is the probably the biggest + + align:start position:0% +this is this is the probably the biggest + + + align:start position:0% +this is this is the probably the biggest +concern I think with the method as I'm + + align:start position:0% +concern I think with the method as I'm + + + align:start position:0% +concern I think with the method as I'm +describing it the biggest issue is + + align:start position:0% +describing it the biggest issue is + + + align:start position:0% +describing it the biggest issue is +you're making an explicit trade-off to + + align:start position:0% +you're making an explicit trade-off to + + + align:start position:0% +you're making an explicit trade-off to +say what I'm interested in doing in this + + align:start position:0% +say what I'm interested in doing in this + + + align:start position:0% +say what I'm interested in doing in this +case is getting some improvement and I'm + + align:start position:0% +case is getting some improvement and I'm + + + align:start position:0% +case is getting some improvement and I'm +willing to make a change in my + + align:start position:0% +willing to make a change in my + + + align:start position:0% +willing to make a change in my +experimental procedure that will give me + + align:start position:0% +experimental procedure that will give me + + + align:start position:0% +experimental procedure that will give me +somewhat less knowledge about why I got + + align:start position:0% +somewhat less knowledge about why I got + + + align:start position:0% +somewhat less knowledge about why I got +the improvement now if you are you know + + align:start position:0% +the improvement now if you are you know + + + align:start position:0% +the improvement now if you are you know +at Ford and you've got three months to + + align:start position:0% +at Ford and you've got three months to + + + align:start position:0% +at Ford and you've got three months to +product release and you you need to meet + + align:start position:0% +product release and you you need to meet + + + align:start position:0% +product release and you you need to meet +your emission standards and the goal is + + align:start position:0% +your emission standards and the goal is + + + align:start position:0% +your emission standards and the goal is +to reduce carbon monoxide in those three + + align:start position:0% +to reduce carbon monoxide in those three + + + align:start position:0% +to reduce carbon monoxide in those three +months and you think the learning that + + align:start position:0% +months and you think the learning that + + + align:start position:0% +months and you think the learning that +you're going to gain about this + + align:start position:0% +you're going to gain about this + + + align:start position:0% +you're going to gain about this +particular engine and its configuration + + align:start position:0% +particular engine and its configuration + + + align:start position:0% +particular engine and its configuration +is not likely to be reusable on the next + + align:start position:0% +is not likely to be reusable on the next + + + align:start position:0% +is not likely to be reusable on the next +one then in that case I think the + + align:start position:0% +one then in that case I think the + + + align:start position:0% +one then in that case I think the +adaptive method makes sense if instead + + align:start position:0% +adaptive method makes sense if instead + + + align:start position:0% +adaptive method makes sense if instead +you think the primary value of your + + align:start position:0% +you think the primary value of your + + + align:start position:0% +you think the primary value of your +experiment is archival right you're + + align:start position:0% +experiment is archival right you're + + + align:start position:0% +experiment is archival right you're +doing the experiment you're going to + + align:start position:0% +doing the experiment you're going to + + + align:start position:0% +doing the experiment you're going to +take the results you're going to make + + align:start position:0% +take the results you're going to make + + + align:start position:0% +take the results you're going to make +them available to all Ford engineers and + + align:start position:0% +them available to all Ford engineers and + + + align:start position:0% +them available to all Ford engineers and +you're going to benefit on the next + + align:start position:0% +you're going to benefit on the next + + + align:start position:0% +you're going to benefit on the next +model and the next model then yeah you + + align:start position:0% +model and the next model then yeah you + + + align:start position:0% +model and the next model then yeah you +probably ought to arrange the + + align:start position:0% +probably ought to arrange the + + + align:start position:0% +probably ought to arrange the +experiments so that you you get the + + align:start position:0% +experiments so that you you get the + + + align:start position:0% +experiments so that you you get the +highest precision of effect estimation + + align:start position:0% +highest precision of effect estimation + + + align:start position:0% +highest precision of effect estimation +the highest validity of inference that's + + align:start position:0% +the highest validity of inference that's + + + align:start position:0% +the highest validity of inference that's +design of experiments factorial design + + align:start position:0% +design of experiments factorial design + + + align:start position:0% +design of experiments factorial design +of experiments but we had an interesting + + align:start position:0% +of experiments but we had an interesting + + + align:start position:0% +of experiments but we had an interesting +learning along the way + + align:start position:0% +learning along the way + + + align:start position:0% +learning along the way +that is to do our big meta studies where + + align:start position:0% +that is to do our big meta studies where + + + align:start position:0% +that is to do our big meta studies where +we're trying to decide how bigger + + align:start position:0% +we're trying to decide how bigger + + + align:start position:0% +we're trying to decide how bigger +interactions when do they occur we went + + align:start position:0% +interactions when do they occur we went + + + align:start position:0% +interactions when do they occur we went +into Ford's databases they had run lots + + align:start position:0% +into Ford's databases they had run lots + + + align:start position:0% +into Ford's databases they had run lots +of experiments in the past and they had + + align:start position:0% +of experiments in the past and they had + + + align:start position:0% +of experiments in the past and they had +them in some kind of company database + + align:start position:0% +them in some kind of company database + + + align:start position:0% +them in some kind of company database +and we were drawing these datasets out + + align:start position:0% +and we were drawing these datasets out + + + align:start position:0% +and we were drawing these datasets out +to put them into one of our studies and + + align:start position:0% +to put them into one of our studies and + + + align:start position:0% +to put them into one of our studies and +very frequently we go through the table + + align:start position:0% +very frequently we go through the table + + + align:start position:0% +very frequently we go through the table +and there was some ambiguity in our + + align:start position:0% +and there was some ambiguity in our + + + align:start position:0% +and there was some ambiguity in our +minds some maybe you know there was a + + align:start position:0% +minds some maybe you know there was a + + + align:start position:0% +minds some maybe you know there was a +plus in in the experimental matrix where + + align:start position:0% +plus in in the experimental matrix where + + + align:start position:0% +plus in in the experimental matrix where +we thought there should have been a + + align:start position:0% +we thought there should have been a + + + align:start position:0% +we thought there should have been a +minus or there's some question and in + + align:start position:0% +minus or there's some question and in + + + align:start position:0% +minus or there's some question and in +those cases we would go track the person + + align:start position:0% +those cases we would go track the person + + + align:start position:0% +those cases we would go track the person +down and ask them what they meant and in + + align:start position:0% +down and ask them what they meant and in + + + align:start position:0% +down and ask them what they meant and in +almost every case that person would say + + align:start position:0% +almost every case that person would say + + + align:start position:0% +almost every case that person would say +huh you're the first person who ever + + align:start position:0% +huh you're the first person who ever + + + align:start position:0% +huh you're the first person who ever +called me about my experiment they'd put + + align:start position:0% +called me about my experiment they'd put + + + align:start position:0% +called me about my experiment they'd put +it in the database and no one was using + + align:start position:0% +it in the database and no one was using + + + align:start position:0% +it in the database and no one was using +it we were the first ones to just to go + + align:start position:0% +it we were the first ones to just to go + + + align:start position:0% +it we were the first ones to just to go +back in and use it so we are not so sang + + align:start position:0% +back in and use it so we are not so sang + + + align:start position:0% +back in and use it so we are not so sang +whine about the prospects of people + + align:start position:0% +whine about the prospects of people + + + align:start position:0% +whine about the prospects of people +reusing experimental data at least so + + align:start position:0% +reusing experimental data at least so + + + align:start position:0% +reusing experimental data at least so +far as you know industrial day-to-day + + align:start position:0% +far as you know industrial day-to-day + + + align:start position:0% +far as you know industrial day-to-day +experimentation is concerned most often + + align:start position:0% +experimentation is concerned most often + + + align:start position:0% +experimentation is concerned most often +those experiments serve their purposes + + align:start position:0% +those experiments serve their purposes + + + align:start position:0% +those experiments serve their purposes +at the time and then they're gone for + + align:start position:0% +at the time and then they're gone for + + + align:start position:0% +at the time and then they're gone for +practical purpose + + align:start position:0% + + + + align:start position:0% + +I guess it is yeah + + align:start position:0% +I guess it is yeah + + + align:start position:0% +I guess it is yeah +and in fact I I never formally tried to + + align:start position:0% +and in fact I I never formally tried to + + + align:start position:0% +and in fact I I never formally tried to +study this but if you if you back off a + + align:start position:0% +study this but if you if you back off a + + + align:start position:0% +study this but if you if you back off a +little bit from our structure and apply + + align:start position:0% +little bit from our structure and apply + + + align:start position:0% +little bit from our structure and apply +some different structure went one that + + align:start position:0% +some different structure went one that + + + align:start position:0% +some different structure went one that +suits your circumstances it's it's + + align:start position:0% +suits your circumstances it's it's + + + align:start position:0% +suits your circumstances it's it's +probably still pretty good it might even + + align:start position:0% +probably still pretty good it might even + + + align:start position:0% +probably still pretty good it might even +be better the the the the bigger point + + align:start position:0% +be better the the the the bigger point + + + align:start position:0% +be better the the the the bigger point +is that you're doing adaptation as you + + align:start position:0% +is that you're doing adaptation as you + + + align:start position:0% +is that you're doing adaptation as you +go and I have been asked the same + + align:start position:0% +go and I have been asked the same + + + align:start position:0% +go and I have been asked the same +question in fact Jeff who asked me at + + align:start position:0% +question in fact Jeff who asked me at + + + align:start position:0% +question in fact Jeff who asked me at +the last time I presented a conference + + align:start position:0% +the last time I presented a conference + + + align:start position:0% +the last time I presented a conference +heat he asked how much of this result is + + align:start position:0% +heat he asked how much of this result is + + + align:start position:0% +heat he asked how much of this result is +due to adaptation and how much is due to + + align:start position:0% +due to adaptation and how much is due to + + + align:start position:0% +due to adaptation and how much is due to +the one factor at a time part because + + align:start position:0% +the one factor at a time part because + + + align:start position:0% +the one factor at a time part because +this is both and it's a hard question to + + align:start position:0% +this is both and it's a hard question to + + + align:start position:0% +this is both and it's a hard question to +answer my sense is it's mostly + + align:start position:0% +answer my sense is it's mostly + + + align:start position:0% +answer my sense is it's mostly +adaptation on the other hand one factor + + align:start position:0% +adaptation on the other hand one factor + + + align:start position:0% +adaptation on the other hand one factor +at a time in some sense optimizes + + align:start position:0% +at a time in some sense optimizes + + + align:start position:0% +at a time in some sense optimizes +adaptation you can add you can be + + align:start position:0% +adaptation you can add you can be + + + align:start position:0% +adaptation you can add you can be +adaptive all the time with every new + + align:start position:0% +adaptive all the time with every new + + + align:start position:0% +adaptive all the time with every new +observation as much as possible so it's + + align:start position:0% +observation as much as possible so it's + + + align:start position:0% +observation as much as possible so it's +not it's not as if I can cleanly + + align:start position:0% +not it's not as if I can cleanly + + + align:start position:0% +not it's not as if I can cleanly +decompose the two contributions to the + + align:start position:0% +decompose the two contributions to the + + + align:start position:0% +decompose the two contributions to the +result but my sense is that it's mostly + + align:start position:0% +result but my sense is that it's mostly + + + align:start position:0% +result but my sense is that it's mostly +adaptation and if you're doing some + + align:start position:0% +adaptation and if you're doing some + + + align:start position:0% +adaptation and if you're doing some +other adaptive procedure especially if + + align:start position:0% +other adaptive procedure especially if + + + align:start position:0% +other adaptive procedure especially if +it's informed by some kind of prior + + align:start position:0% +it's informed by some kind of prior + + + align:start position:0% +it's informed by some kind of prior +knowledge or topical area knowledge it's + + align:start position:0% +knowledge or topical area knowledge it's + + + align:start position:0% +knowledge or topical area knowledge it's +probably a good approach + + align:start position:0% + + + + align:start position:0% + +so I'll just tell you about this one + + align:start position:0% +so I'll just tell you about this one + + + align:start position:0% +so I'll just tell you about this one +last thing okay we did an investigation + + align:start position:0% +last thing okay we did an investigation + + + align:start position:0% +last thing okay we did an investigation +about another kind of uncertainty in in + + align:start position:0% +about another kind of uncertainty in in + + + align:start position:0% +about another kind of uncertainty in in +large system so let's say that you're + + align:start position:0% +large system so let's say that you're + + + align:start position:0% +large system so let's say that you're +you're developing the next tractor or + + align:start position:0% +you're developing the next tractor or + + + align:start position:0% +you're developing the next tractor or +the next car and you think about + + align:start position:0% +the next car and you think about + + + align:start position:0% +the next car and you think about +applying some robust design to the + + align:start position:0% +applying some robust design to the + + + align:start position:0% +applying some robust design to the +system now for any reasonable scale + + align:start position:0% +system now for any reasonable scale + + + align:start position:0% +system now for any reasonable scale +product there are literally thousands of + + align:start position:0% +product there are literally thousands of + + + align:start position:0% +product there are literally thousands of +things which you could potentially apply + + align:start position:0% +things which you could potentially apply + + + align:start position:0% +things which you could potentially apply +a robust design experiment to you can + + align:start position:0% +a robust design experiment to you can + + + align:start position:0% +a robust design experiment to you can +run one on fuel injection you can run + + align:start position:0% +run one on fuel injection you can run + + + align:start position:0% +run one on fuel injection you can run +one on Carver on braking and one on + + align:start position:0% +one on Carver on braking and one on + + + align:start position:0% +one on Carver on braking and one on +environmental controls and one on + + align:start position:0% +environmental controls and one on + + + align:start position:0% +environmental controls and one on +electrical you know and just keep going + + align:start position:0% +electrical you know and just keep going + + + align:start position:0% +electrical you know and just keep going +and you're not going to do them all in + + align:start position:0% +and you're not going to do them all in + + + align:start position:0% +and you're not going to do them all in +fact I would say less than 5% of all + + align:start position:0% +fact I would say less than 5% of all + + + align:start position:0% +fact I would say less than 5% of all +opportunities to do robustness + + align:start position:0% +opportunities to do robustness + + + align:start position:0% +opportunities to do robustness +improvement work are actually executed + + align:start position:0% +improvement work are actually executed + + + align:start position:0% +improvement work are actually executed +and then the question I always ask + + align:start position:0% +and then the question I always ask + + + align:start position:0% +and then the question I always ask +myself is I wonder if let's say it's 5% + + align:start position:0% +myself is I wonder if let's say it's 5% + + + align:start position:0% +myself is I wonder if let's say it's 5% +I wonder if companies are doing the + + align:start position:0% +I wonder if companies are doing the + + + align:start position:0% +I wonder if companies are doing the +right 5% I wonder if they know where + + align:start position:0% +right 5% I wonder if they know where + + + align:start position:0% +right 5% I wonder if they know where +their biggest quality problems are now + + align:start position:0% +their biggest quality problems are now + + + align:start position:0% +their biggest quality problems are now +we know for a fact that if you look at + + align:start position:0% +we know for a fact that if you look at + + + align:start position:0% +we know for a fact that if you look at +retrospectively where there have been + + align:start position:0% +retrospectively where there have been + + + align:start position:0% +retrospectively where there have been +big quality problems if I look at Ford + + align:start position:0% +big quality problems if I look at Ford + + + align:start position:0% +big quality problems if I look at Ford +Explorer and the roll over and so on + + align:start position:0% +Explorer and the roll over and so on + + + align:start position:0% +Explorer and the roll over and so on +right I know they didn't do her a bus + + align:start position:0% +right I know they didn't do her a bus + + + align:start position:0% +right I know they didn't do her a bus +design study on tire inflation and it's + + align:start position:0% +design study on tire inflation and it's + + + align:start position:0% +design study on tire inflation and it's +delamination and rollover they didn't + + align:start position:0% +delamination and rollover they didn't + + + align:start position:0% +delamination and rollover they didn't +they didn't do it now why didn't they + + align:start position:0% +they didn't do it now why didn't they + + + align:start position:0% +they didn't do it now why didn't they +know that that was the one to do robust + + align:start position:0% +know that that was the one to do robust + + + align:start position:0% +know that that was the one to do robust +design on well they just didn't it was + + align:start position:0% +design on well they just didn't it was + + + align:start position:0% +design on well they just didn't it was +not so likely after all it wasn't + + align:start position:0% +not so likely after all it wasn't + + + align:start position:0% +not so likely after all it wasn't +happening to other SUVs so I asked + + align:start position:0% +happening to other SUVs so I asked + + + align:start position:0% +happening to other SUVs so I asked +myself if you could run a relatively + + align:start position:0% +myself if you could run a relatively + + + align:start position:0% +myself if you could run a relatively +expensive robust design study on 5% + + align:start position:0% +expensive robust design study on 5% + + + align:start position:0% +expensive robust design study on 5% +that's let's say that's the case you + + align:start position:0% +that's let's say that's the case you + + + align:start position:0% +that's let's say that's the case you +have the budget for that what if you did + + align:start position:0% +have the budget for that what if you did + + + align:start position:0% +have the budget for that what if you did +something a tenth as expensive and did + + align:start position:0% +something a tenth as expensive and did + + + align:start position:0% +something a tenth as expensive and did +on 50% of the system so we would call + + align:start position:0% +on 50% of the system so we would call + + + align:start position:0% +on 50% of the system so we would call +this idea of streamlining we know how to + + align:start position:0% +this idea of streamlining we know how to + + + align:start position:0% +this idea of streamlining we know how to +take any robust design experiment people + + align:start position:0% +take any robust design experiment people + + + align:start position:0% +take any robust design experiment people +are proposing and to do something + + align:start position:0% +are proposing and to do something + + + align:start position:0% +are proposing and to do something +little bit loose but to do it in a tenth + + align:start position:0% +little bit loose but to do it in a tenth + + + align:start position:0% +little bit loose but to do it in a tenth +of the cost and you'll get about 80% of + + align:start position:0% +of the cost and you'll get about 80% of + + + align:start position:0% +of the cost and you'll get about 80% of +the same benefit right the the trade-off + + align:start position:0% +the same benefit right the the trade-off + + + align:start position:0% +the same benefit right the the trade-off +works like it's it's a good old purrito + + align:start position:0% +works like it's it's a good old purrito + + + align:start position:0% +works like it's it's a good old purrito +80/20 sort of trade-off and we ask + + align:start position:0% +80/20 sort of trade-off and we ask + + + align:start position:0% +80/20 sort of trade-off and we ask +ourselves how that trade-off in doing + + align:start position:0% +ourselves how that trade-off in doing + + + align:start position:0% +ourselves how that trade-off in doing +relatively many relatively less perfect + + align:start position:0% +relatively many relatively less perfect + + + align:start position:0% +relatively many relatively less perfect +experiments compares to doing a few very + + align:start position:0% +experiments compares to doing a few very + + + align:start position:0% +experiments compares to doing a few very +good ones and we ask ourselves how this + + align:start position:0% +good ones and we ask ourselves how this + + + align:start position:0% +good ones and we ask ourselves how this +trade-off is affected by the likelihood + + align:start position:0% +trade-off is affected by the likelihood + + + align:start position:0% +trade-off is affected by the likelihood +of identifying the one or two biggest + + align:start position:0% +of identifying the one or two biggest + + + align:start position:0% +of identifying the one or two biggest +quality problems that you face because + + align:start position:0% +quality problems that you face because + + + align:start position:0% +quality problems that you face because +you know that rollover thing cost for it + + align:start position:0% +you know that rollover thing cost for it + + + align:start position:0% +you know that rollover thing cost for it +a lot you would pay a lot of money to + + align:start position:0% +a lot you would pay a lot of money to + + + align:start position:0% +a lot you would pay a lot of money to +avoid that one and so are the big + + align:start position:0% +avoid that one and so are the big + + + align:start position:0% +avoid that one and so are the big +conclusion of our study is you would + + align:start position:0% +conclusion of our study is you would + + + align:start position:0% +conclusion of our study is you would +have to have a pretty high probability + + align:start position:0% +have to have a pretty high probability + + + align:start position:0% +have to have a pretty high probability +of knowing exactly where your problems + + align:start position:0% +of knowing exactly where your problems + + + align:start position:0% +of knowing exactly where your problems +were in order to do it the way they do + + align:start position:0% +were in order to do it the way they do + + + align:start position:0% +were in order to do it the way they do +it now which is a relatively small + + align:start position:0% +it now which is a relatively small + + + align:start position:0% +it now which is a relatively small +number of expensive studies you'd have + + align:start position:0% +number of expensive studies you'd have + + + align:start position:0% +number of expensive studies you'd have +to know like 95% certainty where your + + align:start position:0% +to know like 95% certainty where your + + + align:start position:0% +to know like 95% certainty where your +biggest quality problem is if you are at + + align:start position:0% +biggest quality problem is if you are at + + + align:start position:0% +biggest quality problem is if you are at +least a little uncertain if you think + + align:start position:0% +least a little uncertain if you think + + + align:start position:0% +least a little uncertain if you think +you're only 70% sure where your problems + + align:start position:0% +you're only 70% sure where your problems + + + align:start position:0% +you're only 70% sure where your problems +lie scale them all back by a factor of + + align:start position:0% +lie scale them all back by a factor of + + + align:start position:0% +lie scale them all back by a factor of +10 and do 10 times as many you'll be + + align:start position:0% +10 and do 10 times as many you'll be + + + align:start position:0% +10 and do 10 times as many you'll be +much better off that's my view and we + + align:start position:0% +much better off that's my view and we + + + align:start position:0% +much better off that's my view and we +didn't have to make so many assumptions + + align:start position:0% +didn't have to make so many assumptions + + + align:start position:0% +didn't have to make so many assumptions +to come to this conclusion people's + + align:start position:0% +to come to this conclusion people's + + + align:start position:0% +to come to this conclusion people's +uncertainty about where their biggest + + align:start position:0% +uncertainty about where their biggest + + + align:start position:0% +uncertainty about where their biggest +issues lie are bigger than they think + + align:start position:0% +issues lie are bigger than they think + + + align:start position:0% +issues lie are bigger than they think +and therefore they need to get sort of + + align:start position:0% +and therefore they need to get sort of + + + align:start position:0% +and therefore they need to get sort of +democratized these kind of processes + + align:start position:0% +democratized these kind of processes + + + align:start position:0% +democratized these kind of processes +it's not that you have to do them very + + align:start position:0% +it's not that you have to do them very + + + align:start position:0% +it's not that you have to do them very +very well in a few cases what you need + + align:start position:0% +very well in a few cases what you need + + + align:start position:0% +very well in a few cases what you need +to do is make sure every engineer knows + + align:start position:0% +to do is make sure every engineer knows + + + align:start position:0% +to do is make sure every engineer knows +how to do this kind of thing and that + + align:start position:0% +how to do this kind of thing and that + + + align:start position:0% +how to do this kind of thing and that +they're doing it to almost everything at + + align:start position:0% +they're doing it to almost everything at + + + align:start position:0% +they're doing it to almost everything at +least almost everything that that for + + align:start position:0% +least almost everything that that for + + + align:start position:0% +least almost everything that that for +example is not proven in the field + + align:start position:0% +example is not proven in the field + + + align:start position:0% +example is not proven in the field +already I mean you don't need to do it + + align:start position:0% +already I mean you don't need to do it + + + align:start position:0% +already I mean you don't need to do it +on the alternator because you use that + + align:start position:0% +on the alternator because you use that + + + align:start position:0% +on the alternator because you use that +same alternator on the last three models + + align:start position:0% +same alternator on the last three models + + + align:start position:0% +same alternator on the last three models +and it's fine but for anything that's + + align:start position:0% +and it's fine but for anything that's + + + align:start position:0% +and it's fine but for anything that's +relatively new you need to be doing some + + align:start position:0% +relatively new you need to be doing some + + + align:start position:0% +relatively new you need to be doing some +of this robustness refinement + + align:start position:0% +of this robustness refinement + + + align:start position:0% +of this robustness refinement +and even if you do just a few + + align:start position:0% +and even if you do just a few + + + align:start position:0% +and even if you do just a few +experiments exposing your systems to up + + align:start position:0% +experiments exposing your systems to up + + + align:start position:0% +experiments exposing your systems to up +to harsh conditions making changes + + align:start position:0% +to harsh conditions making changes + + + align:start position:0% +to harsh conditions making changes +making improvements on the basis of what + + align:start position:0% +making improvements on the basis of what + + + align:start position:0% +making improvements on the basis of what +that reveals that's the key thing not so + + align:start position:0% +that reveals that's the key thing not so + + + align:start position:0% +that reveals that's the key thing not so +much the finesse you apply and anyway + + align:start position:0% +much the finesse you apply and anyway + + + align:start position:0% +much the finesse you apply and anyway +that's the conclusion we came to so far + + align:start position:0% +that's the conclusion we came to so far + + + align:start position:0% +that's the conclusion we came to so far +due to this research so our main + + align:start position:0% +due to this research so our main + + + align:start position:0% +due to this research so our main +conclusions are that we we can show + + align:start position:0% +conclusions are that we we can show + + + align:start position:0% +conclusions are that we we can show +through empirical work and through + + align:start position:0% +through empirical work and through + + + align:start position:0% +through empirical work and through +theorems that this adaptive procedure + + align:start position:0% +theorems that this adaptive procedure + + + align:start position:0% +theorems that this adaptive procedure +gives benefits you get a long way toward + + align:start position:0% +gives benefits you get a long way toward + + + align:start position:0% +gives benefits you get a long way toward +your results that are desired + + align:start position:0% +your results that are desired + + + align:start position:0% +your results that are desired +especially when interactions are not so + + align:start position:0% +especially when interactions are not so + + + align:start position:0% +especially when interactions are not so +small and that you can cross these + + align:start position:0% +small and that you can cross these + + + align:start position:0% +small and that you can cross these +adaptive experiments with fractional + + align:start position:0% +adaptive experiments with fractional + + + align:start position:0% +adaptive experiments with fractional +factorial designs to use them for + + align:start position:0% +factorial designs to use them for + + + align:start position:0% +factorial designs to use them for +robustness and it seems to work pretty + + align:start position:0% +robustness and it seems to work pretty + + + align:start position:0% +robustness and it seems to work pretty +well now I think I'm pretty much out of + + align:start position:0% +well now I think I'm pretty much out of + + + align:start position:0% +well now I think I'm pretty much out of +time now if you if you all have ideas + + align:start position:0% +time now if you if you all have ideas + + + align:start position:0% +time now if you if you all have ideas +for your case studies I'm always + + align:start position:0% +for your case studies I'm always + + + align:start position:0% +for your case studies I'm always +interested in head-to-head comparisons + + align:start position:0% +interested in head-to-head comparisons + + + align:start position:0% +interested in head-to-head comparisons +of experimental designs being done in + + align:start position:0% +of experimental designs being done in + + + align:start position:0% +of experimental designs being done in +companies and the adaptive procedures + + align:start position:0% +companies and the adaptive procedures + + + align:start position:0% +companies and the adaptive procedures +that I'm talking about now so I if + + align:start position:0% +that I'm talking about now so I if + + + align:start position:0% +that I'm talking about now so I if +you're interested in doing such things + + align:start position:0% +you're interested in doing such things + + + align:start position:0% +you're interested in doing such things +for your projects I'm interested in + + align:start position:0% +for your projects I'm interested in + + + align:start position:0% +for your projects I'm interested in +helping you to do that and you can see + + align:start position:0% +helping you to do that and you can see + + + align:start position:0% +helping you to do that and you can see +my email there in case you want to take + + align:start position:0% +my email there in case you want to take + + + align:start position:0% +my email there in case you want to take +me up on the offer okay all right all + + align:start position:0% +me up on the offer okay all right all + + + align:start position:0% +me up on the offer okay all right all +right good day + + align:start position:0% + + + + align:start position:0% + +problems that we run into quite often in + + align:start position:0% +problems that we run into quite often in + + + align:start position:0% +problems that we run into quite often in +microfabrication is that the metrology + + align:start position:0% +microfabrication is that the metrology + + + align:start position:0% +microfabrication is that the metrology +of the things that we've made takes up + + align:start position:0% +of the things that we've made takes up + + + align:start position:0% +of the things that we've made takes up +quite a lot of our time budgets and is + + align:start position:0% +quite a lot of our time budgets and is + + + align:start position:0% +quite a lot of our time budgets and is +quite easy to vary grammars and make + + align:start position:0% +quite easy to vary grammars and make + + + align:start position:0% +quite easy to vary grammars and make +many samples but choosing which ones to + + align:start position:0% +many samples but choosing which ones to + + + align:start position:0% +many samples but choosing which ones to +measure might be the biggest challenge + + align:start position:0% +measure might be the biggest challenge + + + align:start position:0% +measure might be the biggest challenge +and I wonder whether you've looked at + + align:start position:0% +and I wonder whether you've looked at + + + align:start position:0% +and I wonder whether you've looked at +situations whether where you know the + + align:start position:0% +situations whether where you know the + + + align:start position:0% +situations whether where you know the +the acquisition of the data lags the + + align:start position:0% +the acquisition of the data lags the + + + align:start position:0% +the acquisition of the data lags the +doing of the experiments but it's sort + + align:start position:0% +doing of the experiments but it's sort + + + align:start position:0% +doing of the experiments but it's sort +of concurrent but you can only measure a + + align:start position:0% +of concurrent but you can only measure a + + + align:start position:0% +of concurrent but you can only measure a +certain portion of the experiments you + + align:start position:0% +certain portion of the experiments you + + + align:start position:0% +certain portion of the experiments you +do you know are there more complicated + + align:start position:0% +do you know are there more complicated + + + align:start position:0% +do you know are there more complicated +situations like that where there's a + + align:start position:0% +situations like that where there's a + + + align:start position:0% +situations like that where there's a +there's a lag but it's not the case that + + align:start position:0% +there's a lag but it's not the case that + + + align:start position:0% +there's a lag but it's not the case that +you do all the experiments and then you + + align:start position:0% +you do all the experiments and then you + + + align:start position:0% +you do all the experiments and then you +do all the measurements it's an + + align:start position:0% +do all the measurements it's an + + + align:start position:0% +do all the measurements it's an +interesting question so you're saying + + align:start position:0% +interesting question so you're saying + + + align:start position:0% +interesting question so you're saying +that there you can do an experiment + + align:start position:0% +that there you can do an experiment + + + align:start position:0% +that there you can do an experiment +there's a time lag then you get an + + align:start position:0% +there's a time lag then you get an + + + align:start position:0% +there's a time lag then you get an +outcome and in some cases it's actually + + align:start position:0% +outcome and in some cases it's actually + + + align:start position:0% +outcome and in some cases it's actually +more complicated in that you get some + + align:start position:0% +more complicated in that you get some + + + align:start position:0% +more complicated in that you get some +indication right away but the more + + align:start position:0% +indication right away but the more + + + align:start position:0% +indication right away but the more +preferred measurement comes later so for + + align:start position:0% +preferred measurement comes later so for + + + align:start position:0% +preferred measurement comes later so for +example sometimes there's a categorical + + align:start position:0% +example sometimes there's a categorical + + + align:start position:0% +example sometimes there's a categorical +variable that comes immediately obvious + + align:start position:0% +variable that comes immediately obvious + + + align:start position:0% +variable that comes immediately obvious +either I heard cheddar or I didn't and + + align:start position:0% +either I heard cheddar or I didn't and + + + align:start position:0% +either I heard cheddar or I didn't and +then later I get a nice measurement of + + align:start position:0% +then later I get a nice measurement of + + + align:start position:0% +then later I get a nice measurement of +surface condition something like that + + align:start position:0% +surface condition something like that + + + align:start position:0% +surface condition something like that +well you know any of these delays tend + + align:start position:0% +well you know any of these delays tend + + + align:start position:0% +well you know any of these delays tend +away in favor of the factorial design is + + align:start position:0% +away in favor of the factorial design is + + + align:start position:0% +away in favor of the factorial design is +compared to the event you just admit + + align:start position:0% +compared to the event you just admit + + + align:start position:0% +compared to the event you just admit +that right away but then I'll say that + + align:start position:0% +that right away but then I'll say that + + + align:start position:0% +that right away but then I'll say that +you know sometimes the even with + + align:start position:0% +you know sometimes the even with + + + align:start position:0% +you know sometimes the even with +categorical variables immediately + + align:start position:0% +categorical variables immediately + + + align:start position:0% +categorical variables immediately +available perceptions you can get a lot + + align:start position:0% +available perceptions you can get a lot + + + align:start position:0% +available perceptions you can get a lot +of the benefit of adaptation from that + + align:start position:0% +of the benefit of adaptation from that + + + align:start position:0% +of the benefit of adaptation from that +yeah okay thank you very much + + align:start position:0% +yeah okay thank you very much + + + align:start position:0% +yeah okay thank you very much +anybody else so what we've arranged to + + align:start position:0% +anybody else so what we've arranged to + + + align:start position:0% +anybody else so what we've arranged to +have an extra half hour today where I + + align:start position:0% +have an extra half hour today where I + + + align:start position:0% +have an extra half hour today where I +can answer questions about problem sets + + align:start position:0% +can answer questions about problem sets + + + align:start position:0% +can answer questions about problem sets +and any questions that you might have in + + align:start position:0% +and any questions that you might have in + + + align:start position:0% +and any questions that you might have in +the run-up to the quiz so I think what + + align:start position:0% +the run-up to the quiz so I think what + + + align:start position:0% +the run-up to the quiz so I think what +we'll do is just go straight into that + + align:start position:0% +we'll do is just go straight into that + + + align:start position:0% +we'll do is just go straight into that +if people if people want to run off at + + align:start position:0% +if people if people want to run off at + + + align:start position:0% +if people if people want to run off at +this point then that's fine + + align:start position:0% + + + + align:start position:0% + +yes yes so there's a few few + + align:start position:0% +yes yes so there's a few few + + + align:start position:0% +yes yes so there's a few few +housekeeping things first yes so problem + + align:start position:0% +housekeeping things first yes so problem + + + align:start position:0% +housekeeping things first yes so problem +sets I will I'll put the solutions 4 6 & + + align:start position:0% +sets I will I'll put the solutions 4 6 & + + + align:start position:0% +sets I will I'll put the solutions 4 6 & +7 up today at some point and I've I put + + align:start position:0% +7 up today at some point and I've I put + + + align:start position:0% +7 up today at some point and I've I put +the 2006 quiz 2 and solutions on the + + align:start position:0% +the 2006 quiz 2 and solutions on the + + + align:start position:0% +the 2006 quiz 2 and solutions on the +website I'm still trying to track down + + align:start position:0% +website I'm still trying to track down + + + align:start position:0% +website I'm still trying to track down +last year's quiz but hopefully that will + + align:start position:0% +last year's quiz but hopefully that will + + + align:start position:0% +last year's quiz but hopefully that will +be up today and yes for problem set 8 I + + align:start position:0% +be up today and yes for problem set 8 I + + + align:start position:0% +be up today and yes for problem set 8 I +know some people have been sending me + + align:start position:0% +know some people have been sending me + + + align:start position:0% +know some people have been sending me +questions which I'm happy to continue to + + align:start position:0% +questions which I'm happy to continue to + + + align:start position:0% +questions which I'm happy to continue to +answer by email I'll be around this + + align:start position:0% +answer by email I'll be around this + + + align:start position:0% +answer by email I'll be around this +afternoon if you want to come and speak + + align:start position:0% +afternoon if you want to come and speak + + + align:start position:0% +afternoon if you want to come and speak +to me in person and yes I lost last week + + align:start position:0% +to me in person and yes I lost last week + + + align:start position:0% +to me in person and yes I lost last week +a few people asked me for extensions I + + align:start position:0% +a few people asked me for extensions I + + + align:start position:0% +a few people asked me for extensions I +mean that's fine if you need an + + align:start position:0% +mean that's fine if you need an + + + align:start position:0% +mean that's fine if you need an +extension you can have an extension I'm + + align:start position:0% +extension you can have an extension I'm + + + align:start position:0% +extension you can have an extension I'm +not super strict about these things so + + align:start position:0% +not super strict about these things so + + + align:start position:0% +not super strict about these things so +okay so really I you know the floor is + + align:start position:0% +okay so really I you know the floor is + + + align:start position:0% +okay so really I you know the floor is +open for you to ask me things and and oh + + align:start position:0% +open for you to ask me things and and oh + + + align:start position:0% +open for you to ask me things and and oh +yes grades 6 & 7 will hopefully be done + + align:start position:0% +yes grades 6 & 7 will hopefully be done + + + align:start position:0% +yes grades 6 & 7 will hopefully be done +within the next day as well but yes + + align:start position:0% + + + + align:start position:0% + +I in question four on problem set eight + + align:start position:0% +I in question four on problem set eight + + + align:start position:0% +I in question four on problem set eight +we're talking about here yes yeah I I + + align:start position:0% +we're talking about here yes yeah I I + + + align:start position:0% +we're talking about here yes yeah I I +think that it's good - it's good to not + + align:start position:0% +think that it's good - it's good to not + + + align:start position:0% +think that it's good - it's good to not +include the quadratic terms in in that + + align:start position:0% +include the quadratic terms in in that + + + align:start position:0% +include the quadratic terms in in that +question although you might want to + + align:start position:0% +question although you might want to + + + align:start position:0% +question although you might want to +consider what would happen if you did an + + align:start position:0% +consider what would happen if you did an + + + align:start position:0% +consider what would happen if you did an +interaction yeah I think that's right + + align:start position:0% + + + + align:start position:0% + +yeah so I mean with it with this we're + + align:start position:0% +yeah so I mean with it with this we're + + + align:start position:0% +yeah so I mean with it with this we're +not really interested in quadratic + + align:start position:0% +not really interested in quadratic + + + align:start position:0% +not really interested in quadratic +factors just look at the the linear + + align:start position:0% +factors just look at the the linear + + + align:start position:0% +factors just look at the the linear +factors and the interactions okay more + + align:start position:0% +factors and the interactions okay more + + + align:start position:0% +factors and the interactions okay more +questions yeah everywhere yeah so I I + + align:start position:0% +questions yeah everywhere yeah so I I + + + align:start position:0% +questions yeah everywhere yeah so I I +wrote this question in an attempt to + + align:start position:0% +wrote this question in an attempt to + + + align:start position:0% +wrote this question in an attempt to +stretch everyone including myself so + + align:start position:0% +stretch everyone including myself so + + + align:start position:0% +stretch everyone including myself so +it's pretty it's pretty subtle I think + + align:start position:0% +it's pretty it's pretty subtle I think + + + align:start position:0% +it's pretty it's pretty subtle I think +but I would say the the right way to + + align:start position:0% +but I would say the the right way to + + + align:start position:0% +but I would say the the right way to +approach this is to is to re recast that + + align:start position:0% +approach this is to is to re recast that + + + align:start position:0% +approach this is to is to re recast that +model in terms of differences between + + align:start position:0% +model in terms of differences between + + + align:start position:0% +model in terms of differences between +the variables and the mean the mean + + align:start position:0% +the variables and the mean the mean + + + align:start position:0% +the variables and the mean the mean +input so if you have you know you have a + + align:start position:0% +input so if you have you know you have a + + + align:start position:0% +input so if you have you know you have a +set of data and those data have a a mean + + align:start position:0% +set of data and those data have a a mean + + + align:start position:0% +set of data and those data have a a mean +value for x1 and a mean value for X 2 so + + align:start position:0% +value for x1 and a mean value for X 2 so + + + align:start position:0% +value for x1 and a mean value for X 2 so +you might write some you know you might + + align:start position:0% +you might write some you know you might + + + align:start position:0% +you might write some you know you might +write it with some new coefficient a + + align:start position:0% + + + + align:start position:0% + +X 2 minus X sorry X 1 bar X 2 bar and + + align:start position:0% +X 2 minus X sorry X 1 bar X 2 bar and + + + align:start position:0% +X 2 minus X sorry X 1 bar X 2 bar and +you know that that will be for some for + + align:start position:0% +you know that that will be for some for + + + align:start position:0% +you know that that will be for some for +some values of over the A's that have + + align:start position:0% +some values of over the A's that have + + + align:start position:0% +some values of over the A's that have +functions of the B's that will be that + + align:start position:0% +functions of the B's that will be that + + + align:start position:0% +functions of the B's that will be that +will be equivalent and then you know if + + align:start position:0% +will be equivalent and then you know if + + + align:start position:0% +will be equivalent and then you know if +it was just the first two terms that + + align:start position:0% +it was just the first two terms that + + + align:start position:0% +it was just the first two terms that +would be exactly the case that was that + + align:start position:0% +would be exactly the case that was that + + + align:start position:0% +would be exactly the case that was that +was derived in May in Spanos and then + + align:start position:0% +was derived in May in Spanos and then + + + align:start position:0% +was derived in May in Spanos and then +this term looks very much like this term + + align:start position:0% +this term looks very much like this term + + + align:start position:0% +this term looks very much like this term +except it's for a different variable so + + align:start position:0% +except it's for a different variable so + + + align:start position:0% +except it's for a different variable so +the standard error of that coefficient + + align:start position:0% +the standard error of that coefficient + + + align:start position:0% +the standard error of that coefficient +you can get up by the same way you got + + align:start position:0% +you can get up by the same way you got + + + align:start position:0% +you can get up by the same way you got +at this one and then if you look at this + + align:start position:0% +at this one and then if you look at this + + + align:start position:0% +at this one and then if you look at this +term well we have this coefficient here + + align:start position:0% +term well we have this coefficient here + + + align:start position:0% +term well we have this coefficient here +well if you're trying to evaluate the + + align:start position:0% +well if you're trying to evaluate the + + + align:start position:0% +well if you're trying to evaluate the +variance of Y hat you've got a product + + align:start position:0% +variance of Y hat you've got a product + + + align:start position:0% +variance of Y hat you've got a product +of two quantities you have an expression + + align:start position:0% +of two quantities you have an expression + + + align:start position:0% +of two quantities you have an expression +for the variance of a 1-1 which you're + + align:start position:0% +for the variance of a 1-1 which you're + + + align:start position:0% +for the variance of a 1-1 which you're +going to get at in a similar way to how + + align:start position:0% +going to get at in a similar way to how + + + align:start position:0% +going to get at in a similar way to how +you get at the expressions for these + + align:start position:0% +you get at the expressions for these + + + align:start position:0% +you get at the expressions for these +variances and you'll see that the + + align:start position:0% +variances and you'll see that the + + + align:start position:0% +variances and you'll see that the +expression for the standard error is a + + align:start position:0% +expression for the standard error is a + + + align:start position:0% +expression for the standard error is a +function of it's going to be a function + + align:start position:0% +function of it's going to be a function + + + align:start position:0% +function of it's going to be a function +of X 1 minus X 1 bar and and you know + + align:start position:0% +of X 1 minus X 1 bar and and you know + + + align:start position:0% +of X 1 minus X 1 bar and and you know +that when you're finding the variance of + + align:start position:0% + + + + align:start position:0% + +some constant times something that you + + align:start position:0% +some constant times something that you + + + align:start position:0% +some constant times something that you +know the variance of u square that + + align:start position:0% +know the variance of u square that + + + align:start position:0% +know the variance of u square that +constant multiply it by the variance of + + align:start position:0% +constant multiply it by the variance of + + + align:start position:0% +constant multiply it by the variance of +the thing that that the constant is x + + align:start position:0% + + + + align:start position:0% + +oh sorry yes I mean yes these are + + align:start position:0% +oh sorry yes I mean yes these are + + + align:start position:0% +oh sorry yes I mean yes these are +exactly there you go + + align:start position:0% +exactly there you go + + + align:start position:0% +exactly there you go +so I mean this is yes you're trying to + + align:start position:0% +so I mean this is yes you're trying to + + + align:start position:0% +so I mean this is yes you're trying to +find a an expression for the for the + + align:start position:0% +find a an expression for the for the + + + align:start position:0% +find a an expression for the for the +confidence interval for you know as a + + align:start position:0% +confidence interval for you know as a + + + align:start position:0% +confidence interval for you know as a +function of X 1 star and X 2 star but at + + align:start position:0% +function of X 1 star and X 2 star but at + + + align:start position:0% +function of X 1 star and X 2 star but at +a given at a given combination of X 1 + + align:start position:0% +a given at a given combination of X 1 + + + align:start position:0% +a given at a given combination of X 1 +star and X 2 star this is the thing that + + align:start position:0% +star and X 2 star this is the thing that + + + align:start position:0% +star and X 2 star this is the thing that +has variance and this for a fixed X 1 + + align:start position:0% +has variance and this for a fixed X 1 + + + align:start position:0% +has variance and this for a fixed X 1 +star is a constant so you know it I + + align:start position:0% +star is a constant so you know it I + + + align:start position:0% +star is a constant so you know it I +don't wanna give too much away but sir I + + align:start position:0% +don't wanna give too much away but sir I + + + align:start position:0% +don't wanna give too much away but sir I +I think this is the right way there may + + align:start position:0% +I think this is the right way there may + + + align:start position:0% +I think this is the right way there may +be some subtleties that escape me so if + + align:start position:0% +be some subtleties that escape me so if + + + align:start position:0% +be some subtleties that escape me so if +you can think of any let me know I think + + align:start position:0% +you can think of any let me know I think + + + align:start position:0% +you can think of any let me know I think +because there aren't any interaction + + align:start position:0% +because there aren't any interaction + + + align:start position:0% +because there aren't any interaction +terms in our model I think that means + + align:start position:0% +terms in our model I think that means + + + align:start position:0% +terms in our model I think that means +that that covariance is don't need to + + align:start position:0% +that that covariance is don't need to + + + align:start position:0% +that that covariance is don't need to +concern you but if you think I'm wrong + + align:start position:0% +concern you but if you think I'm wrong + + + align:start position:0% +concern you but if you think I'm wrong +on that let me know ok + + align:start position:0% + + + + align:start position:0% + +yeah yeah maybe maybe I'm wrong + + align:start position:0% +yeah yeah maybe maybe I'm wrong + + + align:start position:0% +yeah yeah maybe maybe I'm wrong +well if you want to you know if you can + + align:start position:0% +well if you want to you know if you can + + + align:start position:0% +well if you want to you know if you can +work out how to consider that then then + + align:start position:0% +work out how to consider that then then + + + align:start position:0% +work out how to consider that then then +tell me no I don't think so + + align:start position:0% +tell me no I don't think so + + + align:start position:0% +tell me no I don't think so +No + + align:start position:0% + + + + align:start position:0% + +anyone else have we run out of coffee + + align:start position:0% +anyone else have we run out of coffee + + + align:start position:0% +anyone else have we run out of coffee +yes I expect so let's see what it what + + align:start position:0% +yes I expect so let's see what it what + + + align:start position:0% +yes I expect so let's see what it what +are the things that people are most + + align:start position:0% +are the things that people are most + + + align:start position:0% +are the things that people are most +puzzled by in in the material since quiz + + align:start position:0% +puzzled by in in the material since quiz + + + align:start position:0% +puzzled by in in the material since quiz +1 I mean if someone if someone asked you + + align:start position:0% +1 I mean if someone if someone asked you + + + align:start position:0% +1 I mean if someone if someone asked you +to fit fit a model to a factorial + + align:start position:0% +to fit fit a model to a factorial + + + align:start position:0% +to fit fit a model to a factorial +experiments and you didn't have a mini + + align:start position:0% +experiments and you didn't have a mini + + + align:start position:0% +experiments and you didn't have a mini +attack would know what level of + + align:start position:0% +attack would know what level of + + + align:start position:0% +attack would know what level of +confidence could people have in doing + + align:start position:0% +confidence could people have in doing + + + align:start position:0% +confidence could people have in doing +that is it I mean is it really something + + align:start position:0% +that is it I mean is it really something + + + align:start position:0% +that is it I mean is it really something +where you rely on the structure that the + + align:start position:0% +where you rely on the structure that the + + + align:start position:0% +where you rely on the structure that the +software provides to know how to + + align:start position:0% +software provides to know how to + + + align:start position:0% +software provides to know how to +calculate some of the squares and so + + align:start position:0% +calculate some of the squares and so + + + align:start position:0% +calculate some of the squares and so +forth because I can I can foresee you + + align:start position:0% +forth because I can I can foresee you + + + align:start position:0% +forth because I can I can foresee you +know exam questions you know obviously + + align:start position:0% +know exam questions you know obviously + + + align:start position:0% +know exam questions you know obviously +not gonna have me attack we're going to + + align:start position:0% +not gonna have me attack we're going to + + + align:start position:0% +not gonna have me attack we're going to +be dealing with very small numbers of + + align:start position:0% +be dealing with very small numbers of + + + align:start position:0% +be dealing with very small numbers of +data and it's just going to be a case of + + align:start position:0% +data and it's just going to be a case of + + + align:start position:0% +data and it's just going to be a case of +knowing what to subtract from water or + + align:start position:0% +knowing what to subtract from water or + + + align:start position:0% +knowing what to subtract from water or +anything yeah absolutely yeah + + align:start position:0% + + + + align:start position:0% + +yes fair point + + align:start position:0% +yes fair point + + + align:start position:0% +yes fair point +yeah I need to I need to track it down + + align:start position:0% +yeah I need to I need to track it down + + + align:start position:0% +yeah I need to I need to track it down +because they didn't post it on stellar + + align:start position:0% +because they didn't post it on stellar + + + align:start position:0% +because they didn't post it on stellar +last year so I need to get it off day + + align:start position:0% +last year so I need to get it off day + + + align:start position:0% +last year so I need to get it off day +apart + + align:start position:0% + + + + align:start position:0% + +yeah sure sure yeah this this questions + + align:start position:0% +yeah sure sure yeah this this questions + + + align:start position:0% +yeah sure sure yeah this this questions +a bit cryptic but really all it's asking + + align:start position:0% +a bit cryptic but really all it's asking + + + align:start position:0% +a bit cryptic but really all it's asking +you to do is is confirm your + + align:start position:0% +you to do is is confirm your + + + align:start position:0% +you to do is is confirm your +understanding of the last question on + + align:start position:0% +understanding of the last question on + + + align:start position:0% +understanding of the last question on +problem sets 7 you may recall recall + + align:start position:0% +problem sets 7 you may recall recall + + + align:start position:0% +problem sets 7 you may recall recall +from that from that question where you + + align:start position:0% +from that from that question where you + + + align:start position:0% +from that from that question where you +made that factor that factor Z that + + align:start position:0% +made that factor that factor Z that + + + align:start position:0% +made that factor that factor Z that +noise factor you were you were imagining + + align:start position:0% +noise factor you were you were imagining + + + align:start position:0% +noise factor you were you were imagining +that you could control it in that + + align:start position:0% +that you could control it in that + + + align:start position:0% +that you could control it in that +situation but then I I think you you + + align:start position:0% +situation but then I I think you you + + + align:start position:0% +situation but then I I think you you +will have written an expression for Y in + + align:start position:0% +will have written an expression for Y in + + + align:start position:0% +will have written an expression for Y in +terms of the two x's and that and the Z + + align:start position:0% +terms of the two x's and that and the Z + + + align:start position:0% +terms of the two x's and that and the Z +factor that showed that the sensitivity + + align:start position:0% +factor that showed that the sensitivity + + + align:start position:0% +factor that showed that the sensitivity +of the outputs to variations in Z were a + + align:start position:0% +of the outputs to variations in Z were a + + + align:start position:0% +of the outputs to variations in Z were a +function of X 1 and X 2 so you could you + + align:start position:0% +function of X 1 and X 2 so you could you + + + align:start position:0% +function of X 1 and X 2 so you could you +could choose a combination of the of the + + align:start position:0% +could choose a combination of the of the + + + align:start position:0% +could choose a combination of the of the +control parameters at X 1 and X 2 that + + align:start position:0% +control parameters at X 1 and X 2 that + + + align:start position:0% +control parameters at X 1 and X 2 that +would minimize the sensitivity to Z now + + align:start position:0% +would minimize the sensitivity to Z now + + + align:start position:0% +would minimize the sensitivity to Z now +really parts B and C of problem for are + + align:start position:0% +really parts B and C of problem for are + + + align:start position:0% +really parts B and C of problem for are +just to do checking but that that went + + align:start position:0% +just to do checking but that that went + + + align:start position:0% +just to do checking but that that went +in because if you can't control Z but + + align:start position:0% +in because if you can't control Z but + + + align:start position:0% +in because if you can't control Z but +you know that you know if you're not + + align:start position:0% +you know that you know if you're not + + + align:start position:0% +you know that you know if you're not +controlling it it's probably going to + + align:start position:0% +controlling it it's probably going to + + + align:start position:0% +controlling it it's probably going to +have a variance the input the noise + + align:start position:0% +have a variance the input the noise + + + align:start position:0% +have a variance the input the noise +input is probably going to have a + + align:start position:0% +input is probably going to have a + + + align:start position:0% +input is probably going to have a +variance that doesn't change with time + + align:start position:0% +variance that doesn't change with time + + + align:start position:0% +variance that doesn't change with time +so you can see how much of that noise + + align:start position:0% +so you can see how much of that noise + + + align:start position:0% +so you can see how much of that noise +propagates through to the outputs if the + + align:start position:0% +propagates through to the outputs if the + + + align:start position:0% +propagates through to the outputs if the +noise interacts with the control input + + align:start position:0% +noise interacts with the control input + + + align:start position:0% +noise interacts with the control input +variables in other words if there are + + align:start position:0% +variables in other words if there are + + + align:start position:0% +variables in other words if there are +these product terms of Z and X 1 you + + align:start position:0% +these product terms of Z and X 1 you + + + align:start position:0% +these product terms of Z and X 1 you +can't control Z you can't control X 1 + + align:start position:0% +can't control Z you can't control X 1 + + + align:start position:0% +can't control Z you can't control X 1 +therefore you can control + + align:start position:0% +therefore you can control + + + align:start position:0% +therefore you can control +how much the noise propagates through to + + align:start position:0% +how much the noise propagates through to + + + align:start position:0% +how much the noise propagates through to +the output and and then B and C aren't + + align:start position:0% +the output and and then B and C aren't + + + align:start position:0% +the output and and then B and C aren't +asking you to write down very much it's + + align:start position:0% +asking you to write down very much it's + + + align:start position:0% +asking you to write down very much it's +just sort of checking that the concept + + align:start position:0% +just sort of checking that the concept + + + align:start position:0% +just sort of checking that the concept +is there really does that answer your + + align:start position:0% +is there really does that answer your + + + align:start position:0% +is there really does that answer your +question + + align:start position:0% + + + + align:start position:0% + +okay anyone else stay that's a very good + + align:start position:0% +okay anyone else stay that's a very good + + + align:start position:0% +okay anyone else stay that's a very good +idea yes yeah I'll try to come up with + + align:start position:0% +idea yes yeah I'll try to come up with + + + align:start position:0% +idea yes yeah I'll try to come up with +something yeah that's sort of manageable + + align:start position:0% +something yeah that's sort of manageable + + + align:start position:0% +something yeah that's sort of manageable +on a sheet of paper yes very very good + + align:start position:0% +on a sheet of paper yes very very good + + + align:start position:0% +on a sheet of paper yes very very good +thought we may I mean yeah we may be + + align:start position:0% +thought we may I mean yeah we may be + + + align:start position:0% +thought we may I mean yeah we may be +able to do it with some of the some of + + align:start position:0% +able to do it with some of the some of + + + align:start position:0% +able to do it with some of the some of +the datasets we used to look at and over + + align:start position:0% +the datasets we used to look at and over + + + align:start position:0% +the datasets we used to look at and over +but yeah fine + + align:start position:0% + + + + align:start position:0% + +yes + + align:start position:0% + + + + align:start position:0% + +right right + + align:start position:0% + + + + align:start position:0% + +including okay fine fine so that was on + + align:start position:0% +including okay fine fine so that was on + + + align:start position:0% +including okay fine fine so that was on +problem set seven you were twelve one or + + align:start position:0% +problem set seven you were twelve one or + + + align:start position:0% +problem set seven you were twelve one or +something + + align:start position:0% +something + + + align:start position:0% +something +yeah yeah right no that's that's a good + + align:start position:0% +yeah yeah right no that's that's a good + + + align:start position:0% +yeah yeah right no that's that's a good +point a lot of people had that I will + + align:start position:0% +point a lot of people had that I will + + + align:start position:0% +point a lot of people had that I will +look as well okay yeah I think I think + + align:start position:0% +look as well okay yeah I think I think + + + align:start position:0% +look as well okay yeah I think I think +there is a mistake in Montgomery I need + + align:start position:0% +there is a mistake in Montgomery I need + + + align:start position:0% +there is a mistake in Montgomery I need +to track it down + + align:start position:0% + + + + align:start position:0% + +okay yeah yeah you're right + + align:start position:0% +okay yeah yeah you're right + + + align:start position:0% +okay yeah yeah you're right +eight-point yeah right well I sure I can + + align:start position:0% +eight-point yeah right well I sure I can + + + align:start position:0% +eight-point yeah right well I sure I can +I can try to find I complete derivation + + align:start position:0% +I can try to find I complete derivation + + + align:start position:0% +I can try to find I complete derivation +I think it's probably not worth spending + + align:start position:0% +I think it's probably not worth spending + + + align:start position:0% +I think it's probably not worth spending +a lot of time trying to understand that + + align:start position:0% +a lot of time trying to understand that + + + align:start position:0% +a lot of time trying to understand that +I would focus more on on the stuff + + align:start position:0% +I would focus more on on the stuff + + + align:start position:0% +I would focus more on on the stuff +that's been in the problem sets but sure + + align:start position:0% +that's been in the problem sets but sure + + + align:start position:0% +that's been in the problem sets but sure +I can I can try to find that yeah + + align:start position:0% + + + + align:start position:0% + +yes I'm sure you're right I'm sure + + align:start position:0% +yes I'm sure you're right I'm sure + + + align:start position:0% +yes I'm sure you're right I'm sure +you're right \ No newline at end of file diff --git a/71dUZmywpOM.txt b/71dUZmywpOM.txt new file mode 100644 index 0000000000000000000000000000000000000000..db415c848b87e68847ebfaf6af765dcd711cdba5 --- /dev/null +++ b/71dUZmywpOM.txt @@ -0,0 +1,1235 @@ +align:start position:0% + +so we've discussed + + align:start position:0% +so we've discussed + + + align:start position:0% +so we've discussed +the extent to which the size of a + + align:start position:0% +the extent to which the size of a + + + align:start position:0% +the extent to which the size of a +droplet can influence the infectivity or + + align:start position:0% +droplet can influence the infectivity or + + + align:start position:0% +droplet can influence the infectivity or +the ability of + + align:start position:0% +the ability of + + + align:start position:0% +the ability of +a virion to escape from that droplet and + + align:start position:0% +a virion to escape from that droplet and + + + align:start position:0% +a virion to escape from that droplet and +also to be transmitted to the deepest + + align:start position:0% +also to be transmitted to the deepest + + + align:start position:0% +also to be transmitted to the deepest +smallest passages in the lungs as a + + align:start position:0% +smallest passages in the lungs as a + + + align:start position:0% +smallest passages in the lungs as a +function of its size + + align:start position:0% +function of its size + + + align:start position:0% +function of its size +there's also a dependence on the + + align:start position:0% +there's also a dependence on the + + + align:start position:0% +there's also a dependence on the +relative humidity of the air + + align:start position:0% +relative humidity of the air + + + align:start position:0% +relative humidity of the air +which is related to size since as we've + + align:start position:0% +which is related to size since as we've + + + align:start position:0% +which is related to size since as we've +seen humidity does vary the size + + align:start position:0% +seen humidity does vary the size + + + align:start position:0% +seen humidity does vary the size +but there's believed to be also a more + + align:start position:0% +but there's believed to be also a more + + + align:start position:0% +but there's believed to be also a more +direct effect of humidity as i will now + + align:start position:0% +direct effect of humidity as i will now + + + align:start position:0% +direct effect of humidity as i will now +try to explain so i'm relying here on + + align:start position:0% +try to explain so i'm relying here on + + + align:start position:0% +try to explain so i'm relying here on +the recent work + + align:start position:0% +the recent work + + + align:start position:0% +the recent work +of the group of lindsey marr two two + + align:start position:0% +of the group of lindsey marr two two + + + align:start position:0% +of the group of lindsey marr two two +papers uh cited here + + align:start position:0% +papers uh cited here + + + align:start position:0% +papers uh cited here +so we can distinguish between two + + align:start position:0% +so we can distinguish between two + + + align:start position:0% +so we can distinguish between two +different types of pathogens the first + + align:start position:0% +different types of pathogens the first + + + align:start position:0% +different types of pathogens the first +or the bacteria + + align:start position:0% +or the bacteria + + + align:start position:0% +or the bacteria +and here there's a monotonic dependence + + align:start position:0% +and here there's a monotonic dependence + + + align:start position:0% +and here there's a monotonic dependence +of the + + align:start position:0% +of the + + + align:start position:0% +of the +relative viability of the pathogen of + + align:start position:0% +relative viability of the pathogen of + + + align:start position:0% +relative viability of the pathogen of +the bacteria + + align:start position:0% +the bacteria + + + align:start position:0% +the bacteria +um after a certain time period let's say + + align:start position:0% +um after a certain time period let's say + + + align:start position:0% +um after a certain time period let's say +one hour + + align:start position:0% +one hour + + + align:start position:0% +one hour +and what is found is that above a + + align:start position:0% +and what is found is that above a + + + align:start position:0% +and what is found is that above a +certain threshold of humidity around 80 + + align:start position:0% +certain threshold of humidity around 80 + + + align:start position:0% +certain threshold of humidity around 80 +percent + + align:start position:0% +percent + + + align:start position:0% +percent +relative humidity that there's + + align:start position:0% +relative humidity that there's + + + align:start position:0% +relative humidity that there's +essentially no change in the viability + + align:start position:0% +essentially no change in the viability + + + align:start position:0% +essentially no change in the viability +of the bacteria they're alive they're + + align:start position:0% +of the bacteria they're alive they're + + + align:start position:0% +of the bacteria they're alive they're +infectious + + align:start position:0% +infectious + + + align:start position:0% +infectious +uh but as the humidity relative humidity + + align:start position:0% +uh but as the humidity relative humidity + + + align:start position:0% +uh but as the humidity relative humidity +is reduced + + align:start position:0% +is reduced + + + align:start position:0% +is reduced +uh then there's significant drop off in + + align:start position:0% +uh then there's significant drop off in + + + align:start position:0% +uh then there's significant drop off in +viability which depends on the specific + + align:start position:0% +viability which depends on the specific + + + align:start position:0% +viability which depends on the specific +type of viru + + align:start position:0% +type of viru + + + align:start position:0% +type of viru +of bacteria but it's a fairly general + + align:start position:0% +of bacteria but it's a fairly general + + + align:start position:0% +of bacteria but it's a fairly general +trend that it comes down significantly + + align:start position:0% +trend that it comes down significantly + + + align:start position:0% +trend that it comes down significantly +as you approach more dry air + + align:start position:0% +as you approach more dry air + + + align:start position:0% +as you approach more dry air +now what's happening is the size of the + + align:start position:0% +now what's happening is the size of the + + + align:start position:0% +now what's happening is the size of the +droplets is shrinking + + align:start position:0% + + + + align:start position:0% + +in the case of the bacteria we can + + align:start position:0% +in the case of the bacteria we can + + + align:start position:0% +in the case of the bacteria we can +understand to some extent + + align:start position:0% +understand to some extent + + + align:start position:0% +understand to some extent +why this dependence might be here by + + align:start position:0% +why this dependence might be here by + + + align:start position:0% +why this dependence might be here by +thinking about + + align:start position:0% +thinking about + + + align:start position:0% +thinking about +solutes that are present especially + + align:start position:0% +solutes that are present especially + + + align:start position:0% +solutes that are present especially +salts in this in the system + + align:start position:0% +salts in this in the system + + + align:start position:0% +salts in this in the system +but also mucous mucosal proteins that + + align:start position:0% +but also mucous mucosal proteins that + + + align:start position:0% +but also mucous mucosal proteins that +we've also discussed + + align:start position:0% +we've also discussed + + + align:start position:0% +we've also discussed +and when the the particles become more + + align:start position:0% +and when the the particles become more + + + align:start position:0% +and when the the particles become more +dry + + align:start position:0% +dry + + + align:start position:0% +dry +then what happens is that the + + align:start position:0% +then what happens is that the + + + align:start position:0% +then what happens is that the +concentration goes up and there's an + + align:start position:0% +concentration goes up and there's an + + + align:start position:0% +concentration goes up and there's an +increase in the osmotic pressure + + align:start position:0% +increase in the osmotic pressure + + + align:start position:0% +increase in the osmotic pressure +of the fluid around the bacteria + + align:start position:0% +of the fluid around the bacteria + + + align:start position:0% +of the fluid around the bacteria +relative to the inside + + align:start position:0% +relative to the inside + + + align:start position:0% +relative to the inside +and as with many other kinds of cells + + align:start position:0% +and as with many other kinds of cells + + + align:start position:0% +and as with many other kinds of cells +when exposed to + + align:start position:0% +when exposed to + + + align:start position:0% +when exposed to +such high osmotic pressures that can + + align:start position:0% +such high osmotic pressures that can + + + align:start position:0% +such high osmotic pressures that can +cause + + align:start position:0% +cause + + + align:start position:0% +cause +stress on the cell and potentially even + + align:start position:0% +stress on the cell and potentially even + + + align:start position:0% +stress on the cell and potentially even +rupturing of membranes or other + + align:start position:0% +rupturing of membranes or other + + + align:start position:0% +rupturing of membranes or other +structures within the cell and + + align:start position:0% +structures within the cell and + + + align:start position:0% +structures within the cell and +obviously then is not good for the + + align:start position:0% +obviously then is not good for the + + + align:start position:0% +obviously then is not good for the +viability of that cell and leads to + + align:start position:0% +viability of that cell and leads to + + + align:start position:0% +viability of that cell and leads to +deactivation + + align:start position:0% +deactivation + + + align:start position:0% +deactivation +the case of viruses is a bit more + + align:start position:0% +the case of viruses is a bit more + + + align:start position:0% +the case of viruses is a bit more +complicated + + align:start position:0% +complicated + + + align:start position:0% +complicated +so some old data of harper from the + + align:start position:0% +so some old data of harper from the + + + align:start position:0% +so some old data of harper from the +1960s + + align:start position:0% +1960s + + + align:start position:0% +1960s +on the seasonal flu in particular human + + align:start position:0% +on the seasonal flu in particular human + + + align:start position:0% +on the seasonal flu in particular human +influenza virus + + align:start position:0% +influenza virus + + + align:start position:0% +influenza virus +a which was recently + + align:start position:0% +a which was recently + + + align:start position:0% +a which was recently +analyzed by mars group showed that there + + align:start position:0% +analyzed by mars group showed that there + + + align:start position:0% +analyzed by mars group showed that there +was a viral deactivation rate that + + align:start position:0% +was a viral deactivation rate that + + + align:start position:0% +was a viral deactivation rate that +essentially was scaling + + align:start position:0% +essentially was scaling + + + align:start position:0% +essentially was scaling +linearly with the relative humidity so + + align:start position:0% +linearly with the relative humidity so + + + align:start position:0% +linearly with the relative humidity so +it's uh there's a faster deactivation + + align:start position:0% +it's uh there's a faster deactivation + + + align:start position:0% +it's uh there's a faster deactivation +rate in more humid air + + align:start position:0% +rate in more humid air + + + align:start position:0% +rate in more humid air +less in dry air this is one way we can + + align:start position:0% +less in dry air this is one way we can + + + align:start position:0% +less in dry air this is one way we can +understand the seasonal nature of the + + align:start position:0% +understand the seasonal nature of the + + + align:start position:0% +understand the seasonal nature of the +flu + + align:start position:0% +flu + + + align:start position:0% +flu +in that in more dry wintry environments + + align:start position:0% +in that in more dry wintry environments + + + align:start position:0% +in that in more dry wintry environments +especially away from + + align:start position:0% +especially away from + + + align:start position:0% +especially away from +in sort of the northern or southern + + align:start position:0% +in sort of the northern or southern + + + align:start position:0% +in sort of the northern or southern +hemispheres + + align:start position:0% +hemispheres + + + align:start position:0% +hemispheres +we can expect that then the virus would + + align:start position:0% +we can expect that then the virus would + + + align:start position:0% +we can expect that then the virus would +be deactivating less + + align:start position:0% +be deactivating less + + + align:start position:0% +be deactivating less +but of course that's compounded by the + + align:start position:0% +but of course that's compounded by the + + + align:start position:0% +but of course that's compounded by the +effect that in the winter + + align:start position:0% +effect that in the winter + + + align:start position:0% +effect that in the winter +people spend more time indoors and so + + align:start position:0% +people spend more time indoors and so + + + align:start position:0% +people spend more time indoors and so +that's also leading to + + align:start position:0% +that's also leading to + + + align:start position:0% +that's also leading to +more seasonal transmission now if we + + align:start position:0% +more seasonal transmission now if we + + + align:start position:0% +more seasonal transmission now if we +convert the deactivation rate into a + + align:start position:0% +convert the deactivation rate into a + + + align:start position:0% +convert the deactivation rate into a +relative viability again + + align:start position:0% +relative viability again + + + align:start position:0% +relative viability again +then we see an interesting dependence in + + align:start position:0% +then we see an interesting dependence in + + + align:start position:0% +then we see an interesting dependence in +recent experiments which were done using + + align:start position:0% +recent experiments which were done using + + + align:start position:0% +recent experiments which were done using +bacteriophages which are models + + align:start position:0% +bacteriophages which are models + + + align:start position:0% +bacteriophages which are models +of different kinds of + + align:start position:0% +of different kinds of + + + align:start position:0% +of different kinds of +human pathogens including the seasonal + + align:start position:0% +human pathogens including the seasonal + + + align:start position:0% +human pathogens including the seasonal +flu + + align:start position:0% +flu + + + align:start position:0% +flu +and influenza viruses and in particular + + align:start position:0% +and influenza viruses and in particular + + + align:start position:0% +and influenza viruses and in particular +is a non-monotonic dependence where + + align:start position:0% +is a non-monotonic dependence where + + + align:start position:0% +is a non-monotonic dependence where +essentially there's a maximum rate of + + align:start position:0% +essentially there's a maximum rate of + + + align:start position:0% +essentially there's a maximum rate of +deactivation + + align:start position:0% +deactivation + + + align:start position:0% +deactivation +around the range of 70 or 80 percent + + align:start position:0% +around the range of 70 or 80 percent + + + align:start position:0% +around the range of 70 or 80 percent +humidity + + align:start position:0% +humidity + + + align:start position:0% +humidity +or 60 to 80 and similarly the viability + + align:start position:0% +or 60 to 80 and similarly the viability + + + align:start position:0% +or 60 to 80 and similarly the viability +was the lowest in that range and the way + + align:start position:0% +was the lowest in that range and the way + + + align:start position:0% +was the lowest in that range and the way +the authors proposed uh to explain that + + align:start position:0% +the authors proposed uh to explain that + + + align:start position:0% +the authors proposed uh to explain that +was a hypothesis + + align:start position:0% +was a hypothesis + + + align:start position:0% +was a hypothesis +that there are solutes that are present + + align:start position:0% +that there are solutes that are present + + + align:start position:0% +that there are solutes that are present +which may be for example + + align:start position:0% +which may be for example + + + align:start position:0% +which may be for example +sodium chloride or in particular + + align:start position:0% +sodium chloride or in particular + + + align:start position:0% +sodium chloride or in particular +chloride ions perhaps + + align:start position:0% +chloride ions perhaps + + + align:start position:0% +chloride ions perhaps +that when we reach the higher + + align:start position:0% +that when we reach the higher + + + align:start position:0% +that when we reach the higher +concentration in the shrunken droplets + + align:start position:0% +concentration in the shrunken droplets + + + align:start position:0% +concentration in the shrunken droplets +that there is again a stress on the + + align:start position:0% +that there is again a stress on the + + + align:start position:0% +that there is again a stress on the +virus but in this case + + align:start position:0% +virus but in this case + + + align:start position:0% +virus but in this case +uh regardless of the details of the uh + + align:start position:0% +uh regardless of the details of the uh + + + align:start position:0% +uh regardless of the details of the uh +the + + align:start position:0% +the + + + align:start position:0% +the +the mechanism of deactivation for these + + align:start position:0% +the mechanism of deactivation for these + + + align:start position:0% +the mechanism of deactivation for these +encapsulated viruses + + align:start position:0% +encapsulated viruses + + + align:start position:0% +encapsulated viruses +the idea is that the cumulative dose or + + align:start position:0% +the idea is that the cumulative dose or + + + align:start position:0% +the idea is that the cumulative dose or +exposure to those solids is what's + + align:start position:0% +exposure to those solids is what's + + + align:start position:0% +exposure to those solids is what's +important + + align:start position:0% +important + + + align:start position:0% +important +so if the shrinking happens very fast + + align:start position:0% +so if the shrinking happens very fast + + + align:start position:0% +so if the shrinking happens very fast +and we end up with a droplet nucleus of + + align:start position:0% +and we end up with a droplet nucleus of + + + align:start position:0% +and we end up with a droplet nucleus of +mostly bound water + + align:start position:0% +mostly bound water + + + align:start position:0% +mostly bound water +and it happens over a short period of + + align:start position:0% +and it happens over a short period of + + + align:start position:0% +and it happens over a short period of +time the exposure to those solutes is + + align:start position:0% +time the exposure to those solutes is + + + align:start position:0% +time the exposure to those solutes is +limited and hence we + + align:start position:0% +limited and hence we + + + align:start position:0% +limited and hence we +end up with high viability low + + align:start position:0% +end up with high viability low + + + align:start position:0% +end up with high viability low +deactivation rate + + align:start position:0% +deactivation rate + + + align:start position:0% +deactivation rate +in dry conditions conversely in very + + align:start position:0% +in dry conditions conversely in very + + + align:start position:0% +in dry conditions conversely in very +humid conditions the droplets stay big + + align:start position:0% +humid conditions the droplets stay big + + + align:start position:0% +humid conditions the droplets stay big +in fact they may even grow + + align:start position:0% +in fact they may even grow + + + align:start position:0% +in fact they may even grow +because of the hydroscopic solutes and + + align:start position:0% +because of the hydroscopic solutes and + + + align:start position:0% +because of the hydroscopic solutes and +in that case + + align:start position:0% +in that case + + + align:start position:0% +in that case +there's plenty of solutes presence but + + align:start position:0% +there's plenty of solutes presence but + + + align:start position:0% +there's plenty of solutes presence but +they're very dilute and so again the + + align:start position:0% +they're very dilute and so again the + + + align:start position:0% +they're very dilute and so again the +effect on the virus is minimal + + align:start position:0% +effect on the virus is minimal + + + align:start position:0% +effect on the virus is minimal +and the greatest deactivation and also + + align:start position:0% +and the greatest deactivation and also + + + align:start position:0% +and the greatest deactivation and also +the maximum + + align:start position:0% +the maximum + + + align:start position:0% +the maximum +this or minimum viability is actually at + + align:start position:0% +this or minimum viability is actually at + + + align:start position:0% +this or minimum viability is actually at +an intermediate range of humidities + + align:start position:0% +an intermediate range of humidities + + + align:start position:0% +an intermediate range of humidities +so this tells you that maintaining a + + align:start position:0% +so this tells you that maintaining a + + + align:start position:0% +so this tells you that maintaining a +comfortable humidity in the range of 50 + + align:start position:0% +comfortable humidity in the range of 50 + + + align:start position:0% +comfortable humidity in the range of 50 +to 80 + + align:start position:0% +to 80 + + + align:start position:0% +to 80 +may actually be the best for minimizing + + align:start position:0% +may actually be the best for minimizing + + + align:start position:0% +may actually be the best for minimizing +the viability + + align:start position:0% +the viability + + + align:start position:0% +the viability +of viral pathogens \ No newline at end of file diff --git a/7MWXdi-e-DQ.txt b/7MWXdi-e-DQ.txt new file mode 100644 index 0000000000000000000000000000000000000000..3f04d84d47e37f67dd4834e3a1487e5256008b60 --- /dev/null +++ b/7MWXdi-e-DQ.txt @@ -0,0 +1,2528 @@ +align:start position:0% + +welcome to New lecture on the binomial + + align:start position:0% +welcome to New lecture on the binomial + + + align:start position:0% +welcome to New lecture on the binomial +theorem uh in this lecture we will look + + align:start position:0% +theorem uh in this lecture we will look + + + align:start position:0% +theorem uh in this lecture we will look +at certain divisibility results uh which + + align:start position:0% +at certain divisibility results uh which + + + align:start position:0% +at certain divisibility results uh which +can be derived based on the binomial + + align:start position:0% +can be derived based on the binomial + + + align:start position:0% +can be derived based on the binomial +theorem so once again recall the + + align:start position:0% +theorem so once again recall the + + + align:start position:0% +theorem so once again recall the +binomial theorem is given by x + y the + + align:start position:0% +binomial theorem is given by x + y the + + + align:start position:0% +binomial theorem is given by x + y the +whole power n equals summation R = 0 to + + align:start position:0% +whole power n equals summation R = 0 to + + + align:start position:0% +whole power n equals summation R = 0 to +n c r x^ n minus r y^ r where we use c r + + align:start position:0% +n c r x^ n minus r y^ r where we use c r + + + align:start position:0% +n c r x^ n minus r y^ r where we use c r +to denote + + align:start position:0% +to denote + + + align:start position:0% +to denote +NCR so to give you a flavor of the kind + + align:start position:0% +NCR so to give you a flavor of the kind + + + align:start position:0% +NCR so to give you a flavor of the kind +of results we'll be looking look at + + align:start position:0% +of results we'll be looking look at + + + align:start position:0% +of results we'll be looking look at +today uh let's look at the first example + + align:start position:0% +today uh let's look at the first example + + + align:start position:0% +today uh let's look at the first example +uh which asks you to show + + align:start position:0% +uh which asks you to show + + + align:start position:0% +uh which asks you to show +that 3 power 2 n + + + align:start position:0% +that 3 power 2 n + + + + align:start position:0% +that 3 power 2 n + +2 - 8 N - + + align:start position:0% +2 - 8 N - + + + align:start position:0% +2 - 8 N - +99 is + + align:start position:0% + + + + align:start position:0% + +divisible by + + align:start position:0% +divisible by + + + align:start position:0% +divisible by +64 uh when N is a natural + + align:start position:0% +64 uh when N is a natural + + + align:start position:0% +64 uh when N is a natural +number + + align:start position:0% + + + + align:start position:0% + +so it asks you to show that this term is + + align:start position:0% +so it asks you to show that this term is + + + align:start position:0% +so it asks you to show that this term is +divisible by 64 for natural numbers + + align:start position:0% +divisible by 64 for natural numbers + + + align:start position:0% +divisible by 64 for natural numbers +n um so at First Sight there doesn't + + align:start position:0% +n um so at First Sight there doesn't + + + align:start position:0% +n um so at First Sight there doesn't +seem to be a binomial expansion you can + + align:start position:0% +seem to be a binomial expansion you can + + + align:start position:0% +seem to be a binomial expansion you can +apply uh to generate this result so we + + align:start position:0% +apply uh to generate this result so we + + + align:start position:0% +apply uh to generate this result so we +would like to create a binomial + + align:start position:0% +would like to create a binomial + + + align:start position:0% +would like to create a binomial +expansion to U derive this result and so + + align:start position:0% +expansion to U derive this result and so + + + align:start position:0% +expansion to U derive this result and so +notice that you have you have an + + align:start position:0% +notice that you have you have an + + + align:start position:0% +notice that you have you have an +exponent here but you also have some + + align:start position:0% +exponent here but you also have some + + + align:start position:0% +exponent here but you also have some +terms here and these terms are in + + align:start position:0% +terms here and these terms are in + + + align:start position:0% +terms here and these terms are in +general not divisible by 64 for n being + + align:start position:0% +general not divisible by 64 for n being + + + align:start position:0% +general not divisible by 64 for n being +natural numbers so you can plug in + + align:start position:0% +natural numbers so you can plug in + + + align:start position:0% +natural numbers so you can plug in +certain natural numbers and you can see + + align:start position:0% +certain natural numbers and you can see + + + align:start position:0% +certain natural numbers and you can see +that this uh this term which is being + + align:start position:0% +that this uh this term which is being + + + align:start position:0% +that this uh this term which is being +subtracted from 3^ 2 n + 2 is not going + + align:start position:0% +subtracted from 3^ 2 n + 2 is not going + + + align:start position:0% +subtracted from 3^ 2 n + 2 is not going +to be divisible by 64 and so we would + + align:start position:0% +to be divisible by 64 and so we would + + + align:start position:0% +to be divisible by 64 and so we would +like to somehow get rid of these terms + + align:start position:0% +like to somehow get rid of these terms + + + align:start position:0% +like to somehow get rid of these terms +and leave the remaining term to be + + align:start position:0% +and leave the remaining term to be + + + align:start position:0% +and leave the remaining term to be +divisible by 64 U so let's look at a way + + align:start position:0% +divisible by 64 U so let's look at a way + + + align:start position:0% +divisible by 64 U so let's look at a way +of reexpressing this term 3^ 2 n + 2 - 8 + + align:start position:0% +of reexpressing this term 3^ 2 n + 2 - 8 + + + align:start position:0% +of reexpressing this term 3^ 2 n + 2 - 8 +N - 9 9 uh can be written + + align:start position:0% +N - 9 9 uh can be written + + + align:start position:0% +N - 9 9 uh can be written +as uh 9^ n + 1 where I've just taken a + + align:start position:0% +as uh 9^ n + 1 where I've just taken a + + + align:start position:0% +as uh 9^ n + 1 where I've just taken a +power of 2 into 3 and written 3 Square + + align:start position:0% +power of 2 into 3 and written 3 Square + + + align:start position:0% +power of 2 into 3 and written 3 Square +as + + align:start position:0% +as + + + align:start position:0% +as +9 and you still have minus 8 8 N - + + align:start position:0% +9 and you still have minus 8 8 N - + + + align:start position:0% +9 and you still have minus 8 8 N - +9 so now this looks a little more + + align:start position:0% +9 so now this looks a little more + + + align:start position:0% +9 so now this looks a little more +promising because you have 9^ n + 1 and + + align:start position:0% +promising because you have 9^ n + 1 and + + + align:start position:0% +promising because you have 9^ n + 1 and +you have a 9 and you have an 8 n so you + + align:start position:0% +you have a 9 and you have an 8 n so you + + + align:start position:0% +you have a 9 and you have an 8 n so you +can get rid of the 8 n potentially by + + align:start position:0% +can get rid of the 8 n potentially by + + + align:start position:0% +can get rid of the 8 n potentially by +writing 9 as uh 1 + 8 raise this power n + + align:start position:0% +writing 9 as uh 1 + 8 raise this power n + + + align:start position:0% +writing 9 as uh 1 + 8 raise this power n ++ 1 and you have 8 n - 9 so this looks a + + align:start position:0% ++ 1 and you have 8 n - 9 so this looks a + + + align:start position:0% ++ 1 and you have 8 n - 9 so this looks a +little more promising and now you have a + + align:start position:0% +little more promising and now you have a + + + align:start position:0% +little more promising and now you have a +term which you can expand using the + + align:start position:0% +term which you can expand using the + + + align:start position:0% +term which you can expand using the +binomial theorem um so let's try and + + align:start position:0% +binomial theorem um so let's try and + + + align:start position:0% +binomial theorem um so let's try and +expand this term so this is nothing + + align:start position:0% +expand this term so this is nothing + + + align:start position:0% +expand this term so this is nothing +but n + 1 + + align:start position:0% +but n + 1 + + + align:start position:0% +but n + 1 +c0 uh * 1^ n + + align:start position:0% +c0 uh * 1^ n + + + align:start position:0% +c0 uh * 1^ n ++1 uh plus n + 1 C1 + + align:start position:0% ++1 uh plus n + 1 C1 + + + align:start position:0% ++1 uh plus n + 1 C1 +* 1^ n * 8 + + align:start position:0% +* 1^ n * 8 + + + align:start position:0% +* 1^ n * 8 ++ n + 1 + + align:start position:0% ++ n + 1 + + + align:start position:0% ++ n + 1 +c 2 1 power n minus 1 h² and so + + align:start position:0% +c 2 1 power n minus 1 h² and so + + + align:start position:0% +c 2 1 power n minus 1 h² and so +on so we'll we'll be concerned about the + + align:start position:0% +on so we'll we'll be concerned about the + + + align:start position:0% +on so we'll we'll be concerned about the +higher order terms later and we have we + + align:start position:0% +higher order terms later and we have we + + + align:start position:0% +higher order terms later and we have we +still subtracting eight and and N from + + align:start position:0% +still subtracting eight and and N from + + + align:start position:0% +still subtracting eight and and N from +this term so let's see how this + + align:start position:0% +this term so let's see how this + + + align:start position:0% +this term so let's see how this +simplifies to uh so this is nothing but + + align:start position:0% +simplifies to uh so this is nothing but + + + align:start position:0% +simplifies to uh so this is nothing but +the first term is one the second term is + + align:start position:0% +the first term is one the second term is + + + align:start position:0% +the first term is one the second term is +n + 1 uh * 1 * 8 and the remaining terms + + align:start position:0% +n + 1 uh * 1 * 8 and the remaining terms + + + align:start position:0% +n + 1 uh * 1 * 8 and the remaining terms +can be so simply written as summation R + + align:start position:0% +can be so simply written as summation R + + + align:start position:0% +can be so simply written as summation R += 2 to n + 1 n + 1 c + + align:start position:0% += 2 to n + 1 n + 1 c + + + align:start position:0% += 2 to n + 1 n + 1 c +r 1^ n + 1 - + + align:start position:0% +r 1^ n + 1 - + + + align:start position:0% +r 1^ n + 1 - +R and + + align:start position:0% + + + + align:start position:0% + +8^ R and you still have to subtract 8 + + align:start position:0% +8^ R and you still have to subtract 8 + + + align:start position:0% +8^ R and you still have to subtract 8 +and and 9 from this expression so this + + align:start position:0% +and and 9 from this expression so this + + + align:start position:0% +and and 9 from this expression so this +looks a little more promising because + + align:start position:0% +looks a little more promising because + + + align:start position:0% +looks a little more promising because +you notice that these first two terms + + align:start position:0% +you notice that these first two terms + + + align:start position:0% +you notice that these first two terms +add up to exactly 8 n + 9 and so you can + + align:start position:0% +add up to exactly 8 n + 9 and so you can + + + align:start position:0% +add up to exactly 8 n + 9 and so you can +cancel these two terms and so you're + + align:start position:0% +cancel these two terms and so you're + + + align:start position:0% +cancel these two terms and so you're +just left with summation R = 2 to n + 1 + + align:start position:0% +just left with summation R = 2 to n + 1 + + + align:start position:0% +just left with summation R = 2 to n + 1 +n + 1 c r uh 1 n + 1 - R is just 1 and + + align:start position:0% +n + 1 c r uh 1 n + 1 - R is just 1 and + + + align:start position:0% +n + 1 c r uh 1 n + 1 - R is just 1 and +you have 8 power + + align:start position:0% +you have 8 power + + + align:start position:0% +you have 8 power +R so this is what we're left with and we + + align:start position:0% +R so this is what we're left with and we + + + align:start position:0% +R so this is what we're left with and we +want to show that this is divisible by + + align:start position:0% +want to show that this is divisible by + + + align:start position:0% +want to show that this is divisible by +64 so notice that the summation runs + + align:start position:0% +64 so notice that the summation runs + + + align:start position:0% +64 so notice that the summation runs +from Ral to 2 so let's rewrite this + + align:start position:0% +from Ral to 2 so let's rewrite this + + + align:start position:0% +from Ral to 2 so let's rewrite this +as summation R = 0 to n -1 n + + + align:start position:0% + + + + align:start position:0% + +1 c r + + 2 8^ r + 2 so we' just used a + + align:start position:0% +1 c r + + 2 8^ r + 2 so we' just used a + + + align:start position:0% +1 c r + + 2 8^ r + 2 so we' just used a +change of indices to rewrite this + + align:start position:0% +change of indices to rewrite this + + + align:start position:0% +change of indices to rewrite this +summation and notice that there's an 8^ + + align:start position:0% +summation and notice that there's an 8^ + + + align:start position:0% +summation and notice that there's an 8^ +two here you can pull that out this is + + align:start position:0% +two here you can pull that out this is + + + align:start position:0% +two here you can pull that out this is +going to be + + align:start position:0% +going to be + + + align:start position:0% +going to be +64 * summation R = 0 to N - + + align:start position:0% +64 * summation R = 0 to N - + + + align:start position:0% +64 * summation R = 0 to N - +1 n + 1 c r + 2 8 power + + align:start position:0% +1 n + 1 c r + 2 8 power + + + align:start position:0% +1 n + 1 c r + 2 8 power +R so you have a 64 here and you wanted + + align:start position:0% +R so you have a 64 here and you wanted + + + align:start position:0% +R so you have a 64 here and you wanted +to show that this term is divisible by + + align:start position:0% +to show that this term is divisible by + + + align:start position:0% +to show that this term is divisible by +64 so that is good so what we have to + + align:start position:0% +64 so that is good so what we have to + + + align:start position:0% +64 so that is good so what we have to +show is that this term is an integer so + + align:start position:0% +show is that this term is an integer so + + + align:start position:0% +show is that this term is an integer so +that's all is um that remains so that + + align:start position:0% +that's all is um that remains so that + + + align:start position:0% +that's all is um that remains so that +term is clearly an integer because uh + + align:start position:0% +term is clearly an integer because uh + + + align:start position:0% +term is clearly an integer because uh +you have a summation of several terms + + align:start position:0% +you have a summation of several terms + + + align:start position:0% +you have a summation of several terms +where each term is uh made up of two + + align:start position:0% +where each term is uh made up of two + + + align:start position:0% +where each term is uh made up of two +integers themselves so 8 power R is an + + align:start position:0% +integers themselves so 8 power R is an + + + align:start position:0% +integers themselves so 8 power R is an +integer and n + 1 c r + 2 again is an + + align:start position:0% +integer and n + 1 c r + 2 again is an + + + align:start position:0% +integer and n + 1 c r + 2 again is an +integer so we have summation of integers + + align:start position:0% +integer so we have summation of integers + + + align:start position:0% +integer so we have summation of integers +and so this term is an integer so we + + align:start position:0% +and so this term is an integer so we + + + align:start position:0% +and so this term is an integer so we +have that this over overall term is + + align:start position:0% +have that this over overall term is + + + align:start position:0% +have that this over overall term is +divisible by 64 which is the desired + + align:start position:0% +divisible by 64 which is the desired + + + align:start position:0% +divisible by 64 which is the desired +result so we've + + align:start position:0% +result so we've + + + align:start position:0% +result so we've +seen U an application of the binomial + + align:start position:0% +seen U an application of the binomial + + + align:start position:0% +seen U an application of the binomial +theorem where we somehow reexpressed our + + align:start position:0% +theorem where we somehow reexpressed our + + + align:start position:0% +theorem where we somehow reexpressed our +given term uh in terms of uh in terms of + + align:start position:0% +given term uh in terms of uh in terms of + + + align:start position:0% +given term uh in terms of uh in terms of +an expression where from where we could + + align:start position:0% +an expression where from where we could + + + align:start position:0% +an expression where from where we could +use the binomial expansion and derive a + + align:start position:0% +use the binomial expansion and derive a + + + align:start position:0% +use the binomial expansion and derive a +divisibility result uh for the original + + align:start position:0% +divisibility result uh for the original + + + align:start position:0% +divisibility result uh for the original +term so let's look at a second + + align:start position:0% +term so let's look at a second + + + align:start position:0% +term so let's look at a second +example + + align:start position:0% +example + + + align:start position:0% +example +this example asks to show + + align:start position:0% +this example asks to show + + + align:start position:0% +this example asks to show +that 2^ + + align:start position:0% +that 2^ + + + align:start position:0% +that 2^ +4n - 2^ n * 7 n + + + align:start position:0% + + + + align:start position:0% + +1 is + + align:start position:0% + + + + align:start position:0% + +divisible + + align:start position:0% +divisible + + + align:start position:0% +divisible +by + + align:start position:0% +by + + + align:start position:0% +by +196 whenever N is a natural + + align:start position:0% +196 whenever N is a natural + + + align:start position:0% +196 whenever N is a natural +number so this example is very similar + + align:start position:0% +number so this example is very similar + + + align:start position:0% +number so this example is very similar +to the previous one and once again we + + align:start position:0% +to the previous one and once again we + + + align:start position:0% +to the previous one and once again we +have to figure out how to rewrite this + + align:start position:0% +have to figure out how to rewrite this + + + align:start position:0% +have to figure out how to rewrite this +original term in a form which is + + align:start position:0% +original term in a form which is + + + align:start position:0% +original term in a form which is +amenable to the binomial expansion so + + align:start position:0% +amenable to the binomial expansion so + + + align:start position:0% +amenable to the binomial expansion so +notice now that we want to show that + + align:start position:0% +notice now that we want to show that + + + align:start position:0% +notice now that we want to show that +this term is diff by + + align:start position:0% +this term is diff by + + + align:start position:0% +this term is diff by +196 and 196 is nothing but 14 square and + + align:start position:0% +196 and 196 is nothing but 14 square and + + + align:start position:0% +196 and 196 is nothing but 14 square and +you have a 7 year and a 2 power n year + + align:start position:0% +you have a 7 year and a 2 power n year + + + align:start position:0% +you have a 7 year and a 2 power n year +so that looks + + align:start position:0% +so that looks + + + align:start position:0% +so that looks +promising so let's see what we can do so + + align:start position:0% +promising so let's see what we can do so + + + align:start position:0% +promising so let's see what we can do so +2 ^ 4 n - 2^ n * 7 n + + + align:start position:0% +2 ^ 4 n - 2^ n * 7 n + + + + align:start position:0% +2 ^ 4 n - 2^ n * 7 n + +1 can be uh Rewritten as 16 power N - 2^ + + align:start position:0% +1 can be uh Rewritten as 16 power N - 2^ + + + align:start position:0% +1 can be uh Rewritten as 16 power N - 2^ +n * 7 n + + + align:start position:0% +n * 7 n + + + + align:start position:0% +n * 7 n + +1 where we just Rewritten 2^ 4 n as 16 + + align:start position:0% +1 where we just Rewritten 2^ 4 n as 16 + + + align:start position:0% +1 where we just Rewritten 2^ 4 n as 16 +power n so now 16 can somehow uh be + + align:start position:0% +power n so now 16 can somehow uh be + + + align:start position:0% +power n so now 16 can somehow uh be +split into 14 and 2 um so we can rewrite + + align:start position:0% +split into 14 and 2 um so we can rewrite + + + align:start position:0% +split into 14 and 2 um so we can rewrite +this as 2 + 14^ n minus 2^ n * 7 n + 1 + + align:start position:0% +this as 2 + 14^ n minus 2^ n * 7 n + 1 + + + align:start position:0% +this as 2 + 14^ n minus 2^ n * 7 n + 1 +so this looks promising because now we + + align:start position:0% +so this looks promising because now we + + + align:start position:0% +so this looks promising because now we +have a 14 appear um in a binomial term + + align:start position:0% +have a 14 appear um in a binomial term + + + align:start position:0% +have a 14 appear um in a binomial term +uh and we want to show that this whole + + align:start position:0% +uh and we want to show that this whole + + + align:start position:0% +uh and we want to show that this whole +term is divisible by + + align:start position:0% +term is divisible by + + + align:start position:0% +term is divisible by +196 which is 14 + + align:start position:0% +196 which is 14 + + + align:start position:0% +196 which is 14 +squ so let's go through the uh motions + + align:start position:0% +squ so let's go through the uh motions + + + align:start position:0% +squ so let's go through the uh motions +again and use the binomial theorem to + + align:start position:0% +again and use the binomial theorem to + + + align:start position:0% +again and use the binomial theorem to +show that this is nothing but n c0 2^ n + + align:start position:0% +show that this is nothing but n c0 2^ n + + + align:start position:0% +show that this is nothing but n c0 2^ n +14^ 0 plus n + + align:start position:0% +14^ 0 plus n + + + align:start position:0% +14^ 0 plus n +C1 uh 2^ nus1 14^ 1 + + align:start position:0% +C1 uh 2^ nus1 14^ 1 + + + align:start position:0% +C1 uh 2^ nus1 14^ 1 +1 plus let's rewrite the higher order + + align:start position:0% +1 plus let's rewrite the higher order + + + align:start position:0% +1 plus let's rewrite the higher order +terms the summation R = to 2 to + + align:start position:0% +terms the summation R = to 2 to + + + align:start position:0% +terms the summation R = to 2 to +n NC r 2^ n minus r 14^ + + align:start position:0% +n NC r 2^ n minus r 14^ + + + align:start position:0% +n NC r 2^ n minus r 14^ +r and we subtract the + + align:start position:0% +r and we subtract the + + + align:start position:0% +r and we subtract the +original 2^ n * 7 n + 1 from this + + align:start position:0% +original 2^ n * 7 n + 1 from this + + + align:start position:0% +original 2^ n * 7 n + 1 from this +expansion so once again you can rewrite + + align:start position:0% +expansion so once again you can rewrite + + + align:start position:0% +expansion so once again you can rewrite +this as um 2^ n + n * 2^ N - 1 * 14 + + + align:start position:0% +this as um 2^ n + n * 2^ N - 1 * 14 + + + + align:start position:0% +this as um 2^ n + n * 2^ N - 1 * 14 + +summation R = 2 to + + align:start position:0% +summation R = 2 to + + + align:start position:0% +summation R = 2 to +n n c + + align:start position:0% +n n c + + + align:start position:0% +n n c +r 2^ nus r 14^ + + align:start position:0% +r 2^ nus r 14^ + + + align:start position:0% +r 2^ nus r 14^ +r and u so we have to subtract 2^ n * 7 + + align:start position:0% +r and u so we have to subtract 2^ n * 7 + + + align:start position:0% +r and u so we have to subtract 2^ n * 7 +n + + + align:start position:0% +n + + + + align:start position:0% +n + +1 so this is nothing but 2^ + + align:start position:0% +1 so this is nothing but 2^ + + + align:start position:0% +1 so this is nothing but 2^ +n + n * 2^ n * 7 that I've factorized 14 + + align:start position:0% +n + n * 2^ n * 7 that I've factorized 14 + + + align:start position:0% +n + n * 2^ n * 7 that I've factorized 14 +as 2 * 7 and you have a resulting + + align:start position:0% +as 2 * 7 and you have a resulting + + + align:start position:0% +as 2 * 7 and you have a resulting +summation R = to 2 to n n c r 2^ n minus + + align:start position:0% +summation R = to 2 to n n c r 2^ n minus + + + align:start position:0% +summation R = to 2 to n n c r 2^ n minus +r 14^ + + align:start position:0% +r 14^ + + + align:start position:0% +r 14^ +r and you subtract 2^ n * 7 n and a 2 + + align:start position:0% +r and you subtract 2^ n * 7 n and a 2 + + + align:start position:0% +r and you subtract 2^ n * 7 n and a 2 +power n where I just expanded this term + + align:start position:0% +power n where I just expanded this term + + + align:start position:0% +power n where I just expanded this term +so notice once again that you can cancel + + align:start position:0% +so notice once again that you can cancel + + + align:start position:0% +so notice once again that you can cancel +the first two terms with the terms being + + align:start position:0% +the first two terms with the terms being + + + align:start position:0% +the first two terms with the terms being +subtracted and you're still left with we + + align:start position:0% +subtracted and you're still left with we + + + align:start position:0% +subtracted and you're still left with we +are only left with this summation R = 2 + + align:start position:0% +are only left with this summation R = 2 + + + align:start position:0% +are only left with this summation R = 2 +to n um n c r 2^ n minus r 14^ r now the + + align:start position:0% +to n um n c r 2^ n minus r 14^ r now the + + + align:start position:0% +to n um n c r 2^ n minus r 14^ r now the +arguments are uh quite similar to the + + align:start position:0% +arguments are uh quite similar to the + + + align:start position:0% +arguments are uh quite similar to the +previous one uh previous example we've + + align:start position:0% +previous one uh previous example we've + + + align:start position:0% +previous one uh previous example we've +seen so I won't go through this in + + align:start position:0% +seen so I won't go through this in + + + align:start position:0% +seen so I won't go through this in +detail you can just rewrite this as 14 s + + align:start position:0% +detail you can just rewrite this as 14 s + + + align:start position:0% +detail you can just rewrite this as 14 s +* summation R = 0 + + align:start position:0% +* summation R = 0 + + + align:start position:0% +* summation R = 0 +to N - + + align:start position:0% +to N - + + + align:start position:0% +to N - +2 n c r + + + align:start position:0% +2 n c r + + + + align:start position:0% +2 n c r + +2 2 power + + align:start position:0% +2 2 power + + + align:start position:0% +2 2 power +nus + + align:start position:0% + + + + align:start position:0% + +r - + + align:start position:0% +r - + + + align:start position:0% +r - +2 and 14 + + align:start position:0% + + + + align:start position:0% + +power where here you started with 2^ n + + align:start position:0% +power where here you started with 2^ n + + + align:start position:0% +power where here you started with 2^ n +minus 2 and so you're starting with 2^ n + + align:start position:0% +minus 2 and so you're starting with 2^ n + + + align:start position:0% +minus 2 and so you're starting with 2^ n +minus 2 again and here you started with + + align:start position:0% +minus 2 again and here you started with + + + align:start position:0% +minus 2 again and here you started with +14 squ and here you start with 14 power + + align:start position:0% +14 squ and here you start with 14 power + + + align:start position:0% +14 squ and here you start with 14 power +0 since I pulled out a 14 Square here so + + align:start position:0% +0 since I pulled out a 14 Square here so + + + align:start position:0% +0 since I pulled out a 14 Square here so +so this is what we are left with and + + align:start position:0% +so this is what we are left with and + + + align:start position:0% +so this is what we are left with and +notice that this summation again is an + + align:start position:0% +notice that this summation again is an + + + align:start position:0% +notice that this summation again is an +integer and we have the summation being + + align:start position:0% +integer and we have the summation being + + + align:start position:0% +integer and we have the summation being +multiplied by 14 squ which is 196 which + + align:start position:0% +multiplied by 14 squ which is 196 which + + + align:start position:0% +multiplied by 14 squ which is 196 which +is again an integer and we wanted to + + align:start position:0% +is again an integer and we wanted to + + + align:start position:0% +is again an integer and we wanted to +show that this term is divisible by 196 + + align:start position:0% +show that this term is divisible by 196 + + + align:start position:0% +show that this term is divisible by 196 +so that's exactly what we've shown since + + align:start position:0% +so that's exactly what we've shown since + + + align:start position:0% +so that's exactly what we've shown since +we've factorized it into a form where we + + align:start position:0% +we've factorized it into a form where we + + + align:start position:0% +we've factorized it into a form where we +have a leading um coefficient of 14 + + align:start position:0% +have a leading um coefficient of 14 + + + align:start position:0% +have a leading um coefficient of 14 +Square um and so we've once again shown + + align:start position:0% +Square um and so we've once again shown + + + align:start position:0% +Square um and so we've once again shown +that the this term isible by 196 + + align:start position:0% +that the this term isible by 196 + + + align:start position:0% +that the this term isible by 196 +whenever N is a natural + + align:start position:0% + + + + align:start position:0% + +number so let's look at a multiple + + align:start position:0% +number so let's look at a multiple + + + align:start position:0% +number so let's look at a multiple +choice question which is uh based on + + align:start position:0% +choice question which is uh based on + + + align:start position:0% +choice question which is uh based on +this flavor of problems so the question + + align:start position:0% +this flavor of problems so the question + + + align:start position:0% +this flavor of problems so the question +asks you to + + align:start position:0% + + + + align:start position:0% + +show asks you uh when 5 power 99 um is + + align:start position:0% +show asks you uh when 5 power 99 um is + + + align:start position:0% +show asks you uh when 5 power 99 um is +divided + + align:start position:0% + + + + align:start position:0% + +by + + align:start position:0% + + + + align:start position:0% + +13 uh the + + align:start position:0% + + + + align:start position:0% + +remainder yes so it asks you to compute + + align:start position:0% +remainder yes so it asks you to compute + + + align:start position:0% +remainder yes so it asks you to compute +the remainder and 5^ 99 is divided by 13 + + align:start position:0% +the remainder and 5^ 99 is divided by 13 + + + align:start position:0% +the remainder and 5^ 99 is divided by 13 +and the options are + + align:start position:0% +and the options are + + + align:start position:0% +and the options are +8 9 + + align:start position:0% +8 9 + + + align:start position:0% +8 9 +10 and none of + + align:start position:0% + + + + align:start position:0% + +these + + align:start position:0% +these + + + align:start position:0% +these +so this is a kind of problem where it's + + align:start position:0% +so this is a kind of problem where it's + + + align:start position:0% +so this is a kind of problem where it's +uh hard to eliminate the options without + + align:start position:0% +uh hard to eliminate the options without + + + align:start position:0% +uh hard to eliminate the options without +actually solving the problem uh because + + align:start position:0% +actually solving the problem uh because + + + align:start position:0% +actually solving the problem uh because +uh you have none of these uh where uh so + + align:start position:0% +uh you have none of these uh where uh so + + + align:start position:0% +uh you have none of these uh where uh so +even if you determine that this + + align:start position:0% +even if you determine that this + + + align:start position:0% +even if you determine that this +remainder is going to be even or odd uh + + align:start position:0% +remainder is going to be even or odd uh + + + align:start position:0% +remainder is going to be even or odd uh +you're not really sure whe which option + + align:start position:0% +you're not really sure whe which option + + + align:start position:0% +you're not really sure whe which option +it is since there's none of these and uh + + align:start position:0% +it is since there's none of these and uh + + + align:start position:0% +it is since there's none of these and uh +even if the remainder is odd you can't + + align:start position:0% +even if the remainder is odd you can't + + + align:start position:0% +even if the remainder is odd you can't +just conclude that the answer is nine uh + + align:start position:0% +just conclude that the answer is nine uh + + + align:start position:0% +just conclude that the answer is nine uh +so you would actually have to derive the + + align:start position:0% +so you would actually have to derive the + + + align:start position:0% +so you would actually have to derive the +result for this example so let's see how + + align:start position:0% +result for this example so let's see how + + + align:start position:0% +result for this example so let's see how +you can rewrite five 5 power 99 to + + align:start position:0% +you can rewrite five 5 power 99 to + + + align:start position:0% +you can rewrite five 5 power 99 to +obtain an amenable result so to to + + align:start position:0% +obtain an amenable result so to to + + + align:start position:0% +obtain an amenable result so to to +arrive at this the solution uh let's try + + align:start position:0% +arrive at this the solution uh let's try + + + align:start position:0% +arrive at this the solution uh let's try +Computing some powers of five uh to see + + align:start position:0% +Computing some powers of five uh to see + + + align:start position:0% +Computing some powers of five uh to see +where that gets us so 5 power 1 is + + align:start position:0% +where that gets us so 5 power 1 is + + + align:start position:0% +where that gets us so 5 power 1 is +5 uh which is quite far from 13 so + + align:start position:0% +5 uh which is quite far from 13 so + + + align:start position:0% +5 uh which is quite far from 13 so +there's not really much you can do about + + align:start position:0% +there's not really much you can do about + + + align:start position:0% +there's not really much you can do about +it uh 5 sare is 25 which is close to a + + align:start position:0% +it uh 5 sare is 25 which is close to a + + + align:start position:0% +it uh 5 sare is 25 which is close to a +multiple of 13 13 * 2 is 26 so this + + align:start position:0% +multiple of 13 13 * 2 is 26 so this + + + align:start position:0% +multiple of 13 13 * 2 is 26 so this +looks promising uh but 5 power 99 is not + + align:start position:0% +looks promising uh but 5 power 99 is not + + + align:start position:0% +looks promising uh but 5 power 99 is not +a direct power of not an integral power + + align:start position:0% +a direct power of not an integral power + + + align:start position:0% +a direct power of not an integral power +of 5 square and so let's try this + + align:start position:0% +of 5 square and so let's try this + + + align:start position:0% +of 5 square and so let's try this +approach let's write 5 power 99 as 5 * 5 + + align:start position:0% +approach let's write 5 power 99 as 5 * 5 + + + align:start position:0% +approach let's write 5 power 99 as 5 * 5 +Power + + align:start position:0% +Power + + + align:start position:0% +Power +98 I've just factorized 5 99 into a more + + align:start position:0% +98 I've just factorized 5 99 into a more + + + align:start position:0% +98 I've just factorized 5 99 into a more +suitable form and now I can write this + + align:start position:0% +suitable form and now I can write this + + + align:start position:0% +suitable form and now I can write this +as 5 * 5 power 5 S power + + align:start position:0% +as 5 * 5 power 5 S power + + + align:start position:0% +as 5 * 5 power 5 S power +49 uh and since I know that 5 square is + + align:start position:0% +49 uh and since I know that 5 square is + + + align:start position:0% +49 uh and since I know that 5 square is +close to a multiple of 13 this is + + align:start position:0% +close to a multiple of 13 this is + + + align:start position:0% +close to a multiple of 13 this is +nothing but 5 + + align:start position:0% + + + + align:start position:0% + +* 26 - + + align:start position:0% +* 26 - + + + align:start position:0% +* 26 - +1^ 49 26 is a multiple of 13 so the + + align:start position:0% +1^ 49 26 is a multiple of 13 so the + + + align:start position:0% +1^ 49 26 is a multiple of 13 so the +divisibility results are going to be + + align:start position:0% +divisibility results are going to be + + + align:start position:0% +divisibility results are going to be +fairly easy to derive + + align:start position:0% +fairly easy to derive + + + align:start position:0% +fairly easy to derive +uh so this is nothing but five * and now + + align:start position:0% +uh so this is nothing but five * and now + + + align:start position:0% +uh so this is nothing but five * and now +you use the binomial expansion of 26 - + + align:start position:0% +you use the binomial expansion of 26 - + + + align:start position:0% +you use the binomial expansion of 26 - +1^ 49 uh so let's see how we can write + + align:start position:0% +1^ 49 uh so let's see how we can write + + + align:start position:0% +1^ 49 uh so let's see how we can write +this it's like + + align:start position:0% +this it's like + + + align:start position:0% +this it's like + + align:start position:0% + + + align:start position:0% +C 0 - 1 power + + align:start position:0% +C 0 - 1 power + + + align:start position:0% +C 0 - 1 power +49 26 power 0 so I'm starting off with + + align:start position:0% +49 26 power 0 so I'm starting off with + + + align:start position:0% +49 26 power 0 so I'm starting off with +-1 power 49 and 26 power 0 since we are + + align:start position:0% +-1 power 49 and 26 power 0 since we are + + + align:start position:0% +-1 power 49 and 26 power 0 since we are +only concerned with uh the power of 26 + + align:start position:0% +only concerned with uh the power of 26 + + + align:start position:0% +only concerned with uh the power of 26 +which is zero since all other terms are + + align:start position:0% +which is zero since all other terms are + + + align:start position:0% +which is zero since all other terms are +going to be divisible by 13 so and you + + align:start position:0% +going to be divisible by 13 so and you + + + align:start position:0% +going to be divisible by 13 so and you +have 49 C1 - 1^ + + align:start position:0% +have 49 C1 - 1^ + + + align:start position:0% +have 49 C1 - 1^ +48 26 power + + align:start position:0% +48 26 power + + + align:start position:0% +48 26 power +1 uh plus so + + align:start position:0% +1 uh plus so + + + align:start position:0% +1 uh plus so +on so this is going to be the expansion + + align:start position:0% +on so this is going to be the expansion + + + align:start position:0% +on so this is going to be the expansion +of 26 - 1 the^ 49 and you have a leading + + align:start position:0% +of 26 - 1 the^ 49 and you have a leading + + + align:start position:0% +of 26 - 1 the^ 49 and you have a leading +term which is five um in this expression + + align:start position:0% +term which is five um in this expression + + + align:start position:0% +term which is five um in this expression +so notice that all of these higher + + align:start position:0% +so notice that all of these higher + + + align:start position:0% +so notice that all of these higher +Powers as I mentioned are going to be + + align:start position:0% +Powers as I mentioned are going to be + + + align:start position:0% +Powers as I mentioned are going to be +divisible by 13 and so since we only + + align:start position:0% +divisible by 13 and so since we only + + + align:start position:0% +divisible by 13 and so since we only +care about remainder that this term + + align:start position:0% +care about remainder that this term + + + align:start position:0% +care about remainder that this term +leaves when divided by 13 we don't + + align:start position:0% +leaves when divided by 13 we don't + + + align:start position:0% +leaves when divided by 13 we don't +really care about these terms which are + + align:start position:0% +really care about these terms which are + + + align:start position:0% +really care about these terms which are +exactly divisible by 13 so this is the + + align:start position:0% +exactly divisible by 13 so this is the + + + align:start position:0% +exactly divisible by 13 so this is the +only remaining term is going to give us + + align:start position:0% +only remaining term is going to give us + + + align:start position:0% +only remaining term is going to give us +um the remainder when you divide 5 power + + align:start position:0% +um the remainder when you divide 5 power + + + align:start position:0% +um the remainder when you divide 5 power +99 by 13 so let's see what that gives us + + align:start position:0% +99 by 13 so let's see what that gives us + + + align:start position:0% +99 by 13 so let's see what that gives us +that's 5 * 49 C 0 is 1 uh * - 1^ 49 is + + align:start position:0% +that's 5 * 49 C 0 is 1 uh * - 1^ 49 is + + + align:start position:0% +that's 5 * 49 C 0 is 1 uh * - 1^ 49 is +-1 * 26 0 is 1 and so this gives us - 5 + + align:start position:0% +-1 * 26 0 is 1 and so this gives us - 5 + + + align:start position:0% +-1 * 26 0 is 1 and so this gives us - 5 +so the remainder when 5^ 99 is divided + + align:start position:0% +so the remainder when 5^ 99 is divided + + + align:start position:0% +so the remainder when 5^ 99 is divided +by 13 is - 5 uh for those of you who + + align:start position:0% +by 13 is - 5 uh for those of you who + + + align:start position:0% +by 13 is - 5 uh for those of you who +aren't used to this kind of notation + + align:start position:0% +aren't used to this kind of notation + + + align:start position:0% +aren't used to this kind of notation +this might seem a little strange that + + align:start position:0% +this might seem a little strange that + + + align:start position:0% +this might seem a little strange that +you get a negative remainder but to just + + align:start position:0% +you get a negative remainder but to just + + + align:start position:0% +you get a negative remainder but to just +get a positive remainder you just add a + + align:start position:0% +get a positive remainder you just add a + + + align:start position:0% +get a positive remainder you just add a +multiple of 13 since we've ignored so + + align:start position:0% +multiple of 13 since we've ignored so + + + align:start position:0% +multiple of 13 since we've ignored so +many multiples of 13 you get a negative + + align:start position:0% +many multiples of 13 you get a negative + + + align:start position:0% +many multiples of 13 you get a negative +number but if you add a multiple of 13 + + align:start position:0% +number but if you add a multiple of 13 + + + align:start position:0% +number but if you add a multiple of 13 +you get 8 so the remainder uh when 5 + + align:start position:0% +you get 8 so the remainder uh when 5 + + + align:start position:0% +you get 8 so the remainder uh when 5 +power 99 is divided by 13 is 8 + + align:start position:0% +power 99 is divided by 13 is 8 + + + align:start position:0% +power 99 is divided by 13 is 8 +for those of you who are familiar with + + align:start position:0% +for those of you who are familiar with + + + align:start position:0% +for those of you who are familiar with +modular arithmetic U you can notice that + + align:start position:0% +modular arithmetic U you can notice that + + + align:start position:0% +modular arithmetic U you can notice that +the approach we took is very similar to + + align:start position:0% +the approach we took is very similar to + + + align:start position:0% +the approach we took is very similar to +the approach you take uh when you use uh + + align:start position:0% +the approach you take uh when you use uh + + + align:start position:0% +the approach you take uh when you use uh +when you do such kinds of problems in + + align:start position:0% +when you do such kinds of problems in + + + align:start position:0% +when you do such kinds of problems in +number Theory where you try to get uh + + align:start position:0% +number Theory where you try to get uh + + + align:start position:0% +number Theory where you try to get uh +try to uh get at a power of five which + + align:start position:0% +try to uh get at a power of five which + + + align:start position:0% +try to uh get at a power of five which +is close to a multiple of 13 and you + + align:start position:0% +is close to a multiple of 13 and you + + + align:start position:0% +is close to a multiple of 13 and you +just used uh remainder arguments where + + align:start position:0% +just used uh remainder arguments where + + + align:start position:0% +just used uh remainder arguments where +you ignored uh terms which were + + align:start position:0% +you ignored uh terms which were + + + align:start position:0% +you ignored uh terms which were +multiples of 13 and So you you're only + + align:start position:0% +multiples of 13 and So you you're only + + + align:start position:0% +multiples of 13 and So you you're only +left with one term since only care about + + align:start position:0% +left with one term since only care about + + + align:start position:0% +left with one term since only care about +the remainder um so this is a sample of + + align:start position:0% +the remainder um so this is a sample of + + + align:start position:0% +the remainder um so this is a sample of +a problem which could appear in an exam + + align:start position:0% +a problem which could appear in an exam + + + align:start position:0% +a problem which could appear in an exam +type situation where you're asked to + + align:start position:0% +type situation where you're asked to + + + align:start position:0% +type situation where you're asked to +derive a result based on the + + align:start position:0% +derive a result based on the + + + align:start position:0% +derive a result based on the +divisibility U of A term U by a natural + + align:start position:0% +divisibility U of A term U by a natural + + + align:start position:0% +divisibility U of A term U by a natural +number uh using the binomial theorem so + + align:start position:0% +number uh using the binomial theorem so + + + align:start position:0% +number uh using the binomial theorem so +that's it for this lecture hope you + + align:start position:0% +that's it for this lecture hope you + + + align:start position:0% +that's it for this lecture hope you +enjoyed watching this lecture uh and in + + align:start position:0% +enjoyed watching this lecture uh and in + + + align:start position:0% +enjoyed watching this lecture uh and in +the next uh lectures we will look at + + align:start position:0% +the next uh lectures we will look at + + + align:start position:0% +the next uh lectures we will look at +some example problems based on the + + align:start position:0% +some example problems based on the + + + align:start position:0% +some example problems based on the +binomial theorem I thank you for your + + align:start position:0% +binomial theorem I thank you for your + + + align:start position:0% +binomial theorem I thank you for your +attention and hope you can join us next + + align:start position:0% +attention and hope you can join us next + + + align:start position:0% +attention and hope you can join us next +time \ No newline at end of file diff --git a/7QJyMB9qGQg.txt b/7QJyMB9qGQg.txt new file mode 100644 index 0000000000000000000000000000000000000000..a257a0c6702c48071bb2898b3d6ed3a6067c059b --- /dev/null +++ b/7QJyMB9qGQg.txt @@ -0,0 +1,499 @@ +align:start position:0% + +radiation therapy is one of the most + + align:start position:0% +radiation therapy is one of the most + + + align:start position:0% +radiation therapy is one of the most +well used applications of optimization + + align:start position:0% +well used applications of optimization + + + align:start position:0% +well used applications of optimization +in healthcare in practice radiation + + align:start position:0% +in healthcare in practice radiation + + + align:start position:0% +in healthcare in practice radiation +machines are connected to treatment + + align:start position:0% +machines are connected to treatment + + + align:start position:0% +machines are connected to treatment +planning software that implements and + + align:start position:0% +planning software that implements and + + + align:start position:0% +planning software that implements and +solves optimization models both linear + + align:start position:0% +solves optimization models both linear + + + align:start position:0% +solves optimization models both linear +optimization models like we saw here and + + align:start position:0% +optimization models like we saw here and + + + align:start position:0% +optimization models like we saw here and +other types of optimization models some + + align:start position:0% +other types of optimization models some + + + align:start position:0% +other types of optimization models some +examples of radiation machines that use + + align:start position:0% +examples of radiation machines that use + + + align:start position:0% +examples of radiation machines that use +optimization software are pinnacle by + + align:start position:0% +optimization software are pinnacle by + + + align:start position:0% +optimization software are pinnacle by +Philips ray station by research labs and + + align:start position:0% +Philips ray station by research labs and + + + align:start position:0% +Philips ray station by research labs and +Eclipse by Varian there are many + + align:start position:0% +Eclipse by Varian there are many + + + align:start position:0% +Eclipse by Varian there are many +extensions to the optimization model we + + align:start position:0% +extensions to the optimization model we + + + align:start position:0% +extensions to the optimization model we +described here one is the selection of + + align:start position:0% +described here one is the selection of + + + align:start position:0% +described here one is the selection of +beam angles the beam angles can be + + align:start position:0% +beam angles the beam angles can be + + + align:start position:0% +beam angles the beam angles can be +selected jointly with the intensity + + align:start position:0% +selected jointly with the intensity + + + align:start position:0% +selected jointly with the intensity +profiles by using integer optimization + + align:start position:0% +profiles by using integer optimization + + + align:start position:0% +profiles by using integer optimization +this allows the treatment to be further + + align:start position:0% +this allows the treatment to be further + + + align:start position:0% +this allows the treatment to be further +personalized to the specific tumor and + + align:start position:0% +personalized to the specific tumor and + + + align:start position:0% +personalized to the specific tumor and +person receiving the radiation integer + + align:start position:0% +person receiving the radiation integer + + + align:start position:0% +person receiving the radiation integer +optimization is another type of + + align:start position:0% +optimization is another type of + + + align:start position:0% +optimization is another type of +optimization model and will be the topic + + align:start position:0% +optimization model and will be the topic + + + align:start position:0% +optimization model and will be the topic +of next week another extension is + + align:start position:0% +of next week another extension is + + + align:start position:0% +of next week another extension is +accounting for uncertainty often the + + align:start position:0% +accounting for uncertainty often the + + + align:start position:0% +accounting for uncertainty often the +quality of imrt treatments is degraded + + align:start position:0% +quality of imrt treatments is degraded + + + align:start position:0% +quality of imrt treatments is degraded +due to uncertain organ motion for + + align:start position:0% +due to uncertain organ motion for + + + align:start position:0% +due to uncertain organ motion for +example in lung cancer the target area + + align:start position:0% +example in lung cancer the target area + + + align:start position:0% +example in lung cancer the target area +is around the lungs but since the + + align:start position:0% +is around the lungs but since the + + + align:start position:0% +is around the lungs but since the +patient is breathing throughout the + + align:start position:0% +patient is breathing throughout the + + + align:start position:0% +patient is breathing throughout the +treatment the target area is moving and + + align:start position:0% +treatment the target area is moving and + + + align:start position:0% +treatment the target area is moving and +the location is slightly uncertain we + + align:start position:0% +the location is slightly uncertain we + + + align:start position:0% +the location is slightly uncertain we +can manage this uncertainty using a + + align:start position:0% +can manage this uncertainty using a + + + align:start position:0% +can manage this uncertainty using a +method known as robust optimization + + align:start position:0% +method known as robust optimization + + + align:start position:0% +method known as robust optimization +there is a significant amount of + + align:start position:0% +there is a significant amount of + + + align:start position:0% +there is a significant amount of +literature on this method and its + + align:start position:0% +literature on this method and its + + + align:start position:0% +literature on this method and its +application to radiation therapy linear + + align:start position:0% +application to radiation therapy linear + + + align:start position:0% +application to radiation therapy linear +optimization significantly improves the + + align:start position:0% +optimization significantly improves the + + + align:start position:0% +optimization significantly improves the +efficiency of radiation therapy manually + + align:start position:0% +efficiency of radiation therapy manually + + + align:start position:0% +efficiency of radiation therapy manually +designing an IMRT treatment would be + + align:start position:0% +designing an IMRT treatment would be + + + align:start position:0% +designing an IMRT treatment would be +inefficient and impractical by using + + align:start position:0% +inefficient and impractical by using + + + align:start position:0% +inefficient and impractical by using +linear optimization + + align:start position:0% +linear optimization + + + align:start position:0% +linear optimization +I am RT can be designed in an efficient + + align:start position:0% +I am RT can be designed in an efficient + + + align:start position:0% +I am RT can be designed in an efficient +and systematic way as we saw in this + + align:start position:0% +and systematic way as we saw in this + + + align:start position:0% +and systematic way as we saw in this +lecture clinical criteria can be modeled + + align:start position:0% +lecture clinical criteria can be modeled + + + align:start position:0% +lecture clinical criteria can be modeled +using constraints and the treatment + + align:start position:0% +using constraints and the treatment + + + align:start position:0% +using constraints and the treatment +planner can explore trade-offs by change + + align:start position:0% +planner can explore trade-offs by change + + + align:start position:0% +planner can explore trade-offs by change +the model but ultimately I am RT in the + + align:start position:0% +the model but ultimately I am RT in the + + + align:start position:0% +the model but ultimately I am RT in the +use of optimization benefits the patient + + align:start position:0% +use of optimization benefits the patient + + + align:start position:0% +use of optimization benefits the patient +in head and neck cancers saliva glands + + align:start position:0% +in head and neck cancers saliva glands + + + align:start position:0% +in head and neck cancers saliva glands +were rarely spared prior to imrt but by + + align:start position:0% +were rarely spared prior to imrt but by + + + align:start position:0% +were rarely spared prior to imrt but by +using optimized + + align:start position:0% +using optimized + + + align:start position:0% +using optimized +imrt treatments saliva glands can now be + + align:start position:0% +imrt treatments saliva glands can now be + + + align:start position:0% +imrt treatments saliva glands can now be +spared in prostate cancer IMRT + + align:start position:0% +spared in prostate cancer IMRT + + + align:start position:0% +spared in prostate cancer IMRT +treatments reduce toxicities and allow + + align:start position:0% +treatments reduce toxicities and allow + + + align:start position:0% +treatments reduce toxicities and allow +for higher tumor doses to be delivered + + align:start position:0% +for higher tumor doses to be delivered + + + align:start position:0% +for higher tumor doses to be delivered +safely and in lung cancer + + align:start position:0% +safely and in lung cancer + + + align:start position:0% +safely and in lung cancer +optimized IMRT reduce the risk of + + align:start position:0% +optimized IMRT reduce the risk of + + + align:start position:0% +optimized IMRT reduce the risk of +radiation induced pneumonitis these are + + align:start position:0% +radiation induced pneumonitis these are + + + align:start position:0% +radiation induced pneumonitis these are +just three examples of the benefits of + + align:start position:0% +just three examples of the benefits of + + + align:start position:0% +just three examples of the benefits of +IMRT overall optimized IMRT allows + + align:start position:0% +IMRT overall optimized IMRT allows + + + align:start position:0% +IMRT overall optimized IMRT allows +clinicians to deliver treatment that was + + align:start position:0% +clinicians to deliver treatment that was + + + align:start position:0% +clinicians to deliver treatment that was +previously impossible and to improve the + + align:start position:0% +previously impossible and to improve the + + + align:start position:0% +previously impossible and to improve the +quality of life for patients \ No newline at end of file diff --git a/7UNiSHGyg1Q.txt b/7UNiSHGyg1Q.txt new file mode 100644 index 0000000000000000000000000000000000000000..b64dc99da45fc11c4d88a32aba86900643d86565 --- /dev/null +++ b/7UNiSHGyg1Q.txt @@ -0,0 +1,2515 @@ +align:start position:0% + +talks about a prospective lng plant that + + align:start position:0% +talks about a prospective lng plant that + + + align:start position:0% +talks about a prospective lng plant that +i worked on with these colleagues uh + + align:start position:0% +i worked on with these colleagues uh + + + align:start position:0% +i worked on with these colleagues uh +kardashian student uh kardash and he + + align:start position:0% +kardashian student uh kardash and he + + + align:start position:0% +kardashian student uh kardash and he +sees this student burani and others + + align:start position:0% + + + + align:start position:0% + +with the + + align:start position:0% +with the + + + align:start position:0% +with the +keppel offshore and marine corporation + + align:start position:0% +keppel offshore and marine corporation + + + align:start position:0% +keppel offshore and marine corporation +which is a big + + align:start position:0% +which is a big + + + align:start position:0% +which is a big +uh shipbuilding + + align:start position:0% +uh shipbuilding + + + align:start position:0% +uh shipbuilding +platform building metal bending uh + + align:start position:0% +platform building metal bending uh + + + align:start position:0% +platform building metal bending uh +uh + + align:start position:0% +uh + + + align:start position:0% +uh +government company + + align:start position:0% +government company + + + align:start position:0% +government company +in singapore and they had this as a + + align:start position:0% +in singapore and they had this as a + + + align:start position:0% +in singapore and they had this as a +prospective case and + + align:start position:0% +prospective case and + + + align:start position:0% +prospective case and +as a they had a commission a design they + + align:start position:0% +as a they had a commission a design they + + + align:start position:0% +as a they had a commission a design they +were working on it for some oil company + + align:start position:0% +were working on it for some oil company + + + align:start position:0% +were working on it for some oil company +and we took this on as a way of thinking + + align:start position:0% +and we took this on as a way of thinking + + + align:start position:0% +and we took this on as a way of thinking +about can one do better as i think + + align:start position:0% +about can one do better as i think + + + align:start position:0% +about can one do better as i think +indeed we can and that's what this is + + align:start position:0% +indeed we can and that's what this is + + + align:start position:0% +indeed we can and that's what this is +about + + align:start position:0% +about + + + align:start position:0% +about +so + + align:start position:0% +so + + + align:start position:0% +so +it is first of all a parametric analysis + + align:start position:0% +it is first of all a parametric analysis + + + align:start position:0% +it is first of all a parametric analysis +that is + + align:start position:0% +that is + + + align:start position:0% +that is +um + + align:start position:0% +um + + + align:start position:0% +um +that is + + align:start position:0% +that is + + + align:start position:0% +that is +uh looks at a significant range of + + align:start position:0% +uh looks at a significant range of + + + align:start position:0% +uh looks at a significant range of +factors there's instead of saying this + + align:start position:0% +factors there's instead of saying this + + + align:start position:0% +factors there's instead of saying this +is the condition that says well what if + + align:start position:0% +is the condition that says well what if + + + align:start position:0% +is the condition that says well what if +the economy of the scale were longer + + align:start position:0% +the economy of the scale were longer + + + align:start position:0% +the economy of the scale were longer +what if the uncertainty was different + + align:start position:0% +what if the uncertainty was different + + + align:start position:0% +what if the uncertainty was different +what if + + align:start position:0% +what if + + + align:start position:0% +what if +learning was a different scale so that + + align:start position:0% +learning was a different scale so that + + + align:start position:0% +learning was a different scale so that +it's designed to illustrate a range of + + align:start position:0% +it's designed to illustrate a range of + + + align:start position:0% +it's designed to illustrate a range of +possible conditions of how you might do + + align:start position:0% +possible conditions of how you might do + + + align:start position:0% +possible conditions of how you might do +it rather than trying to specify a + + align:start position:0% +it rather than trying to specify a + + + align:start position:0% +it rather than trying to specify a +particular one so a design is a learning + + align:start position:0% +particular one so a design is a learning + + + align:start position:0% +particular one so a design is a learning +experience + + align:start position:0% +experience + + + align:start position:0% +experience +i hope you'll find it so + + align:start position:0% +i hope you'll find it so + + + align:start position:0% +i hope you'll find it so +so + + align:start position:0% +so + + + align:start position:0% +so +the + + align:start position:0% +the + + + align:start position:0% +the +general idea is sort of to do mid-text + + align:start position:0% +general idea is sort of to do mid-text + + + align:start position:0% +general idea is sort of to do mid-text +if you want uh that homework in a much + + align:start position:0% +if you want uh that homework in a much + + + align:start position:0% +if you want uh that homework in a much +more detailed and + + align:start position:0% +more detailed and + + + align:start position:0% +more detailed and +complicated situation + + align:start position:0% +complicated situation + + + align:start position:0% +complicated situation +and + + align:start position:0% +and + + + align:start position:0% +and +to what conclusions can we talk about in + + align:start position:0% +to what conclusions can we talk about in + + + align:start position:0% +to what conclusions can we talk about in +terms of preferred strategies notice + + align:start position:0% +terms of preferred strategies notice + + + align:start position:0% +terms of preferred strategies notice +again that i've talked about preferred + + align:start position:0% +again that i've talked about preferred + + + align:start position:0% +again that i've talked about preferred +strategies because there's trade-offs + + align:start position:0% +strategies because there's trade-offs + + + align:start position:0% +strategies because there's trade-offs +about the cost and the and the risk + + align:start position:0% +about the cost and the and the risk + + + align:start position:0% +about the cost and the and the risk +their trade-offs about the political + + align:start position:0% +their trade-offs about the political + + + align:start position:0% +their trade-offs about the political +extent and there's a variety of other + + align:start position:0% +extent and there's a variety of other + + + align:start position:0% +extent and there's a variety of other +factors that are involved in it but um + + align:start position:0% +factors that are involved in it but um + + + align:start position:0% +factors that are involved in it but um +here are the focus on the economic + + align:start position:0% +here are the focus on the economic + + + align:start position:0% +here are the focus on the economic +aspects + + align:start position:0% +aspects + + + align:start position:0% +aspects +so + + align:start position:0% +so + + + align:start position:0% +so +the key conclusion is a flexible can + + align:start position:0% +the key conclusion is a flexible can + + + align:start position:0% +the key conclusion is a flexible can +provide clear economic benefits i don't + + align:start position:0% +provide clear economic benefits i don't + + + align:start position:0% +provide clear economic benefits i don't +say it must + + align:start position:0% +say it must + + + align:start position:0% +say it must +but they + + align:start position:0% +but they + + + align:start position:0% +but they +it's pretty clear that they can provide + + align:start position:0% +it's pretty clear that they can provide + + + align:start position:0% +it's pretty clear that they can provide +it + + align:start position:0% +it + + + align:start position:0% +it +these are pushed + + align:start position:0% +these are pushed + + + align:start position:0% +these are pushed +by + + align:start position:0% +by + + + align:start position:0% +by +discount rate effects and learning + + align:start position:0% +discount rate effects and learning + + + align:start position:0% +discount rate effects and learning +effects discount rate because if you + + align:start position:0% +effects discount rate because if you + + + align:start position:0% +effects discount rate because if you +invest later on it costs less than terms + + align:start position:0% +invest later on it costs less than terms + + + align:start position:0% +invest later on it costs less than terms +of present value learning in fact is + + align:start position:0% +of present value learning in fact is + + + align:start position:0% +of present value learning in fact is +that if you build several modules the + + align:start position:0% +that if you build several modules the + + + align:start position:0% +that if you build several modules the +next time you do it you'll avoid + + align:start position:0% +next time you do it you'll avoid + + + align:start position:0% +next time you do it you'll avoid +mistakes or improve design and so forth + + align:start position:0% +mistakes or improve design and so forth + + + align:start position:0% +mistakes or improve design and so forth +and + + align:start position:0% +and + + + align:start position:0% +and +uh this + + align:start position:0% +uh this + + + align:start position:0% +uh this +comes with building inject often but not + + align:start position:0% +comes with building inject often but not + + + align:start position:0% +comes with building inject often but not +necessarily on some kind of modularity + + align:start position:0% +necessarily on some kind of modularity + + + align:start position:0% +necessarily on some kind of modularity +of design + + align:start position:0% +of design + + + align:start position:0% +of design +and these factors discount rate learning + + align:start position:0% +and these factors discount rate learning + + + align:start position:0% +and these factors discount rate learning +effects module design work against the + + align:start position:0% +effects module design work against the + + + align:start position:0% +effects module design work against the +economies of scale which encourage + + align:start position:0% +economies of scale which encourage + + + align:start position:0% +economies of scale which encourage +people to + + align:start position:0% +people to + + + align:start position:0% +people to +uh build + + align:start position:0% +uh build + + + align:start position:0% +uh build +for all future capacity right up front + + align:start position:0% +for all future capacity right up front + + + align:start position:0% +for all future capacity right up front +which was + + align:start position:0% +which was + + + align:start position:0% +which was +part of the task of the mid-text example + + align:start position:0% +part of the task of the mid-text example + + + align:start position:0% +part of the task of the mid-text example +uh that you worked through was that many + + align:start position:0% +uh that you worked through was that many + + + align:start position:0% +uh that you worked through was that many +people had the + + align:start position:0% +people had the + + + align:start position:0% +people had the +normal reflex was oh yeah that's what we + + align:start position:0% +normal reflex was oh yeah that's what we + + + align:start position:0% +normal reflex was oh yeah that's what we +need we're going to build for it right + + align:start position:0% +need we're going to build for it right + + + align:start position:0% +need we're going to build for it right +at the beginning and not mess around + + align:start position:0% +at the beginning and not mess around + + + align:start position:0% +at the beginning and not mess around +with it but it turns out that that + + align:start position:0% +with it but it turns out that that + + + align:start position:0% +with it but it turns out that that +common reaction is often + + align:start position:0% +common reaction is often + + + align:start position:0% +common reaction is often +anti-economic + + align:start position:0% +anti-economic + + + align:start position:0% +anti-economic +so and also the actual expected value of + + align:start position:0% +so and also the actual expected value of + + + align:start position:0% +so and also the actual expected value of +the capex of the project under + + align:start position:0% +the capex of the project under + + + align:start position:0% +the capex of the project under +uncertainty is less than the + + align:start position:0% +uncertainty is less than the + + + align:start position:0% +uncertainty is less than the +deterministic estimation + + align:start position:0% +deterministic estimation + + + align:start position:0% +deterministic estimation +so + + align:start position:0% +so + + + align:start position:0% +so +uh that's where we're going + + align:start position:0% +uh that's where we're going + + + align:start position:0% +uh that's where we're going +so + + align:start position:0% +so + + + align:start position:0% +so +i'm now giving you + + align:start position:0% +i'm now giving you + + + align:start position:0% +i'm now giving you +taking from it our presentation their + + align:start position:0% +taking from it our presentation their + + + align:start position:0% +taking from it our presentation their +presentation of the analysis has given + + align:start position:0% +presentation of the analysis has given + + + align:start position:0% +presentation of the analysis has given +for a + + align:start position:0% +for a + + + align:start position:0% +for a +a particular project uh a particular + + align:start position:0% +a particular project uh a particular + + + align:start position:0% +a particular project uh a particular +conference and so forth and + + align:start position:0% +conference and so forth and + + + align:start position:0% +conference and so forth and +um + + align:start position:0% +um + + + align:start position:0% +um +let's go + + align:start position:0% +let's go + + + align:start position:0% +let's go +so + + align:start position:0% +so + + + align:start position:0% +so +um + + align:start position:0% + + + + align:start position:0% + +the motivation looking through design + + align:start position:0% +the motivation looking through design + + + align:start position:0% +the motivation looking through design +alternatives the methodology and the + + align:start position:0% +alternatives the methodology and the + + + align:start position:0% +alternatives the methodology and the +results + + align:start position:0% + + + + align:start position:0% + +so in location uh we're talking about + + align:start position:0% +so in location uh we're talking about + + + align:start position:0% +so in location uh we're talking about +the state of victoria which is this bit + + align:start position:0% +the state of victoria which is this bit + + + align:start position:0% +the state of victoria which is this bit +here of australia this is where sydney + + align:start position:0% +here of australia this is where sydney + + + align:start position:0% +here of australia this is where sydney +is new south wales this is where + + align:start position:0% +is new south wales this is where + + + align:start position:0% +is new south wales this is where +brisbane the gold coast is this is where + + align:start position:0% +brisbane the gold coast is this is where + + + align:start position:0% +brisbane the gold coast is this is where +the big mineral area is or some of the + + align:start position:0% +the big mineral area is or some of the + + + align:start position:0% +the big mineral area is or some of the +big mineral on the western australia and + + align:start position:0% +big mineral on the western australia and + + + align:start position:0% +big mineral on the western australia and +perth and this is the great + + align:start position:0% +perth and this is the great + + + align:start position:0% +perth and this is the great +nothing uh if i can put it that way um + + align:start position:0% +nothing uh if i can put it that way um + + + align:start position:0% +nothing uh if i can put it that way um +uh + + align:start position:0% +uh + + + align:start position:0% +uh +and so we're i don't there's tasmania + + align:start position:0% +and so we're i don't there's tasmania + + + align:start position:0% +and so we're i don't there's tasmania +tassie down here + + align:start position:0% +tassie down here + + + align:start position:0% +tassie down here +here is um + + align:start position:0% +here is um + + + align:start position:0% +here is um +a melbourne and there are various sites + + align:start position:0% +a melbourne and there are various sites + + + align:start position:0% +a melbourne and there are various sites +for + + align:start position:0% +for + + + align:start position:0% +for +uh distribution so the plan was to be + + align:start position:0% +uh distribution so the plan was to be + + + align:start position:0% +uh distribution so the plan was to be +here and their sites for distribution of + + align:start 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used to do a certain + + + align:start position:0% +from the offshore used to do a certain +amount of processing + + align:start position:0% +amount of processing + + + align:start position:0% +amount of processing +uh + + align:start position:0% +uh + + + align:start position:0% +uh +separate out the good stuff get rid of + + align:start position:0% +separate out the good stuff get rid of + + + align:start position:0% +separate out the good stuff get rid of +the bad stuff + + align:start position:0% +the bad stuff + + + align:start position:0% +the bad stuff +you have somehow get it to land and then + + align:start position:0% +you have somehow get it to land and then + + + align:start position:0% +you have somehow get it to land and then +you liquefy it and it can be + + align:start position:0% +you liquefy it and it can be + + + align:start position:0% +you liquefy it and it can be +used for a variety of purposes + + align:start position:0% +used for a variety of purposes + + + align:start position:0% +used for a variety of purposes +but the idea here in australia was the + + align:start position:0% +but the idea here in australia was the + + + align:start position:0% +but the idea here in australia was the +project was to market it for the + + align:start position:0% +project was to market it for the + + + align:start position:0% +project was to market it for the +transportation sector that it would be + + align:start position:0% +transportation sector that it would be + + + align:start position:0% +transportation sector that it would be +uh cleaner um + + align:start position:0% +uh cleaner um + + + align:start position:0% +uh cleaner um +than diesel fuel and so forth and it'd + + align:start position:0% +than diesel fuel and so forth and it'd + + + align:start position:0% +than diesel fuel and so forth and it'd +be + + align:start position:0% +be + + + align:start position:0% +be +not only an environmental benefit but it + + align:start position:0% +not only an environmental benefit but it + + + align:start position:0% +not only an environmental benefit but it +would be + + align:start position:0% +would be + + + align:start position:0% +would be +a good business for the oil companies + + align:start position:0% +a good business for the oil companies + + + align:start position:0% +a good business for the oil companies +which unfortunately in the past have + + align:start position:0% +which unfortunately in the past have + + + align:start position:0% +which unfortunately in the past have +often simply burned off the gas flared + + align:start position:0% +often simply burned off the gas flared + + + align:start position:0% +often simply burned off the gas flared +it which is neither profitable nor + + align:start position:0% +it which is neither profitable nor + + + align:start position:0% +it which is neither profitable nor +um + + align:start position:0% +um + + + align:start position:0% +um +environmentally desirable so it's viewed + + align:start position:0% +environmentally desirable so it's viewed + + + align:start position:0% +environmentally desirable so it's viewed +as a in this case as a transportation + + align:start position:0% +as a in this case as a transportation + + + align:start position:0% +as a in this case as a transportation +issue + + align:start position:0% +issue + + + align:start position:0% +issue +uh in europe they use liquid national + + align:start position:0% +uh in europe they use liquid national + + + align:start position:0% +uh in europe they use liquid national +lng for + + align:start position:0% +lng for + + + align:start position:0% +lng for +home heating a lot and + + align:start position:0% +home heating a lot and + + + align:start position:0% +home heating a lot and +also for power plants but uh this is not + + align:start position:0% +also for power plants but uh this is not + + + align:start position:0% +also for power plants but uh this is not +the um + + align:start position:0% +the um + + + align:start position:0% +the um +they don't particularly need heat in + + align:start position:0% +they don't particularly need heat in + + + align:start position:0% +they don't particularly need heat in +australia and south australia + + align:start position:0% + + + + align:start position:0% + +um + + align:start position:0% +um + + + align:start position:0% +um +so + + align:start position:0% +so + + + align:start position:0% +so +there are three uh versions of the + + align:start position:0% +there are three uh versions of the + + + align:start position:0% +there are three uh versions of the +system i want to sketch out for you + + align:start position:0% +system i want to sketch out for you + + + align:start position:0% +system i want to sketch out for you +that is the original design that uh + + align:start position:0% +that is the original design that uh + + + align:start position:0% +that is the original design that uh +keppel offshore and marine had developed + + align:start position:0% +keppel offshore and marine had developed + + + align:start position:0% +keppel offshore and marine had developed +was to have one big plant + + align:start position:0% +was to have one big plant + + + align:start position:0% +was to have one big plant +with the idea then that + + align:start position:0% +with the idea then that + + + align:start position:0% +with the idea then that +the + + align:start position:0% +the + + + align:start position:0% +the +liquid product would be distributed to + + align:start position:0% +liquid product would be distributed to + + + align:start position:0% +liquid product would be distributed to +various sites the five sites i mentioned + + align:start position:0% +various sites the five sites i mentioned + + + align:start position:0% +various sites the five sites i mentioned +and from there they would you be used to + + align:start position:0% +and from there they would you be used to + + + align:start position:0% +and from there they would you be used to +fuel tanker oh + + align:start position:0% +fuel tanker oh + + + align:start position:0% +fuel tanker oh +trucks + + align:start position:0% +trucks + + + align:start position:0% +trucks +uh to uh + + align:start position:0% +uh to uh + + + align:start position:0% +uh to uh +deliver goods and whatever they were + + align:start position:0% +deliver goods and whatever they were + + + align:start position:0% +deliver goods and whatever they were +doing so one big plan economies of scale + + align:start position:0% +doing so one big plan economies of scale + + + align:start position:0% +doing so one big plan economies of scale +very much similar to the big plant + + align:start position:0% +very much similar to the big plant + + + align:start position:0% +very much similar to the big plant +and for the water except that it was not + + align:start position:0% +and for the water except that it was not + + + align:start position:0% +and for the water except that it was not +modular anyway it was one big thing + + align:start position:0% +modular anyway it was one big thing + + + align:start position:0% +modular anyway it was one big thing +so + + align:start position:0% +so + + + align:start position:0% +so +the first + + align:start position:0% +the first + + + align:start position:0% +the first +phase that we looked at kardan me and + + align:start position:0% +phase that we looked at kardan me and + + + align:start position:0% +phase that we looked at kardan me and +the other + + align:start position:0% +the other + + + align:start position:0% +the other +was to have modular plants say all right + + align:start position:0% +was to have modular plants say all right + + + align:start position:0% +was to have modular plants say all right +where instead of having the whole size + + align:start position:0% +where instead of having the whole size + + + align:start position:0% +where instead of having the whole size +at once we're going to say what happened + + align:start position:0% +at once we're going to say what happened + + + align:start position:0% +at once we're going to say what happened +if we had modules of 25 + + align:start position:0% +if we had modules of 25 + + + align:start position:0% +if we had modules of 25 +uh + + align:start position:0% +uh + + + align:start position:0% +uh +tons there's 50 tons 75 100 tons so + + align:start position:0% +tons there's 50 tons 75 100 tons so + + + align:start position:0% +tons there's 50 tons 75 100 tons so +forth so + + align:start position:0% +forth so + + + align:start position:0% +forth so +we could + + align:start position:0% +we could + + + align:start position:0% +we could +what we could do about that was to phase + + align:start position:0% +what we could do about that was to phase + + + align:start position:0% +what we could do about that was to phase +it over time so we start off small + + align:start position:0% +it over time so we start off small + + + align:start position:0% +it over time so we start off small +because the demand was small and we'd + + align:start position:0% +because the demand was small and we'd + + + align:start position:0% +because the demand was small and we'd +add them very similar to the + + align:start position:0% +add them very similar to the + + + align:start position:0% +add them very similar to the +mid-text homework ii example is that all + + align:start position:0% +mid-text homework ii example is that all + + + align:start position:0% +mid-text homework ii example is that all +right what's the best way to to do this + + align:start position:0% +right what's the best way to to do this + + + align:start position:0% +right what's the best way to to do this +and we did this through a simulation + + align:start position:0% +and we did this through a simulation + + + align:start position:0% +and we did this through a simulation +analysis as i'll point out + + align:start position:0% +analysis as i'll point out + + + align:start position:0% +analysis as i'll point out +but + + align:start position:0% +but + + + align:start position:0% +but +so + + align:start position:0% +so + + + align:start position:0% +so +there's we can play around with + + align:start position:0% +there's we can play around with + + + align:start position:0% +there's we can play around with +flexibility as to size one and also as + + align:start position:0% +flexibility as to size one and also as + + + align:start position:0% +flexibility as to size one and also as +to + + align:start position:0% +to + + + align:start position:0% +to +timing because of + + align:start position:0% +timing because of + + + align:start position:0% +timing because of +the size what is the right size and when + + align:start position:0% +the size what is the right size and when + + + align:start position:0% +the size what is the right size and when +do we time the additions + + align:start position:0% +do we time the additions + + + align:start position:0% +do we time the additions +but the third thing is we can also think + + align:start position:0% +but the third thing is we can also think + + + align:start position:0% +but the third thing is we can also think +about the um + + align:start position:0% +about the um + + + align:start position:0% +about the um +flexible design so that we can locate + + align:start position:0% +flexible design so that we can locate + + + align:start position:0% +flexible design so that we can locate +the + + align:start position:0% +the + + + align:start position:0% +the +plant elsewhere that + + align:start position:0% +plant elsewhere that + + + align:start position:0% +plant elsewhere that +as in many processes electric power for + + align:start position:0% +as in many processes electric power for + + + align:start position:0% +as in many processes electric power for +example + + align:start position:0% +example + + + align:start position:0% +example +if you do everything in one large plant + + align:start position:0% +if you do everything in one large plant + + + align:start position:0% +if you do everything in one large plant +power for example you gotta transmit it + + align:start position:0% +power for example you gotta transmit it + + + align:start position:0% +power for example you gotta transmit it +a long ways to where it's actually being + + align:start position:0% +a long ways to where it's actually being + + + align:start position:0% +a long ways to where it's actually being +used right now in new england + + align:start position:0% +used right now in new england + + + align:start position:0% +used right now in new england +we are getting + + align:start position:0% +we are getting + + + align:start position:0% +we are getting +a fair amount of power from + + align:start position:0% +a fair amount of power from + + + align:start position:0% +a fair amount of power from +northern quebec which is transmitted + + align:start position:0% +northern quebec which is transmitted + + + align:start position:0% +northern quebec which is transmitted +through high voltage lines all the way + + align:start position:0% +through high voltage lines all the way + + + align:start position:0% +through high voltage lines all the way +down to boston or + + align:start position:0% +down to boston or + + + align:start position:0% +down to boston or +the boston area and + + align:start position:0% +the boston area and + + + align:start position:0% +the boston area and +that's + + align:start position:0% +that's + + + align:start position:0% +that's +uh maybe economical as + + align:start position:0% +uh maybe economical as + + + align:start position:0% +uh maybe economical as +as compared to building a plant but it + + align:start position:0% +as compared to building a plant but it + + + align:start position:0% +as compared to building a plant but it +costs a lot so if you can avoid + + align:start position:0% +costs a lot so if you can avoid + + + align:start position:0% +costs a lot so if you can avoid +the transportation costs and do it + + align:start position:0% +the transportation costs and do it + + + align:start position:0% +the transportation costs and do it +locally it might be better so + + align:start position:0% +locally it might be better so + + + align:start position:0% +locally it might be better so +having a thought that maybe will have a + + align:start position:0% +having a thought that maybe will have a + + + align:start position:0% +having a thought that maybe will have a +decentralized units of production + + align:start position:0% +decentralized units of production + + + align:start position:0% +decentralized units of production +a standard issue whether you're doing + + align:start position:0% +a standard issue whether you're doing + + + align:start position:0% +a standard issue whether you're doing +warehouses or electric power production + + align:start position:0% +warehouses or electric power production + + + align:start position:0% +warehouses or electric power production +or almost anything is not just how much + + align:start position:0% +or almost anything is not just how much + + + align:start position:0% +or almost anything is not just how much +capacity you have but where do you have + + align:start position:0% +capacity you have but where do you have + + + align:start position:0% +capacity you have but where do you have +it at what time so it's a + + align:start position:0% +it at what time so it's a + + + align:start position:0% +it at what time so it's a +generalizable + + align:start position:0% +generalizable + + + align:start position:0% +generalizable +uh example to applicable in thinking to + + align:start position:0% +uh example to applicable in thinking to + + + align:start position:0% +uh example to applicable in thinking to +many issues + + align:start position:0% +many issues + + + align:start position:0% +many issues +so here's a schema for + + align:start position:0% +so here's a schema for + + + align:start position:0% +so here's a schema for +the design and it's very similar to the + + align:start position:0% +the design and it's very similar to the + + + align:start position:0% +the design and it's very similar to the +the analysis this schema is very similar + + align:start position:0% +the analysis this schema is very similar + + + align:start position:0% +the analysis this schema is very similar +to + + align:start position:0% +to + + + align:start position:0% +to +the garage case so the first step one + + align:start position:0% +the garage case so the first step one + + + align:start position:0% +the garage case so the first step one +was to say all right let's build the + + align:start position:0% +was to say all right let's build the + + + align:start position:0% +was to say all right let's build the +model of how this thing performs um + + align:start position:0% +model of how this thing performs um + + + align:start position:0% +model of how this thing performs um +uh as a one single large plant + + align:start position:0% +uh as a one single large plant + + + align:start position:0% +uh as a one single large plant +and + + align:start position:0% +and + + + align:start position:0% +and +uh + + align:start position:0% +uh + + + align:start position:0% +uh +then because of the parametric one we + + align:start position:0% +then because of the parametric one we + + + align:start position:0% +then because of the parametric one we +say all right let's suppose we have a we + + align:start position:0% +say all right let's suppose we have a we + + + align:start position:0% +say all right let's suppose we have a we +know the demand is going to be we assume + + align:start position:0% +know the demand is going to be we assume + + + align:start position:0% +know the demand is going to be we assume +that do a deterministic analysis and + + align:start position:0% +that do a deterministic analysis and + + + align:start position:0% +that do a deterministic analysis and +think about what is the right size for + + align:start position:0% +think about what is the right size for + + + align:start position:0% +think about what is the right size for +the plant we ought to build + + align:start position:0% +the plant we ought to build + + + align:start position:0% +the plant we ought to build +that is that of course depends upon the + + align:start position:0% +that is that of course depends upon the + + + align:start position:0% +that is that of course depends upon the +economies of scale so that depending + + align:start position:0% +economies of scale so that depending + + + align:start position:0% +economies of scale so that depending +upon the economy the scale you build a + + align:start position:0% +upon the economy the scale you build a + + + align:start position:0% +upon the economy the scale you build a +smaller and then expand it or not this + + align:start position:0% +smaller and then expand it or not this + + + align:start position:0% +smaller and then expand it or not this +is the same kind of thing that man did + + align:start position:0% +is the same kind of thing that man did + + + align:start position:0% +is the same kind of thing that man did +um + + align:start position:0% +um + + + align:start position:0% +um +in his very simple model that i showed + + align:start position:0% +in his very simple model that i showed + + + align:start position:0% +in his very simple model that i showed +you a couple of weeks ago + + align:start position:0% +you a couple of weeks ago + + + align:start position:0% +you a couple of weeks ago +so deterministic model first that's the + + align:start position:0% +so deterministic model first that's the + + + align:start position:0% +so deterministic model first that's the +base case + + align:start position:0% +base case + + + align:start position:0% +base case +secondly we said okay + + align:start position:0% +secondly we said okay + + + align:start position:0% +secondly we said okay +we recognize there's uncertainty so + + align:start position:0% +we recognize there's uncertainty so + + + align:start position:0% +we recognize there's uncertainty so +we're going to think about this and + + align:start position:0% +we're going to think about this and + + + align:start position:0% +we're going to think about this and +we're going to generate a lot of + + align:start position:0% +we're going to generate a lot of + + + align:start position:0% +we're going to generate a lot of +demand scenarios and see how the + + align:start position:0% +demand scenarios and see how the + + + align:start position:0% +demand scenarios and see how the +standard model performs under + + align:start position:0% +standard model performs under + + + align:start position:0% +standard model performs under +uncertainty are they the deterministic + + align:start position:0% +uncertainty are they the deterministic + + + align:start position:0% +uncertainty are they the deterministic +model performs under uncertainty + + align:start position:0% +model performs under uncertainty + + + align:start position:0% +model performs under uncertainty +and what you see is that once you + + align:start position:0% +and what you see is that once you + + + align:start position:0% +and what you see is that once you +recognize uncertainty the + + align:start position:0% +recognize uncertainty the + + + align:start position:0% +recognize uncertainty the +value of the project changes + + align:start position:0% +value of the project changes + + + align:start position:0% +value of the project changes +decreases because it's capacity limited + + align:start position:0% +decreases because it's capacity limited + + + align:start position:0% +decreases because it's capacity limited +in this case and secondly often the + + align:start position:0% +in this case and secondly often the + + + align:start position:0% +in this case and secondly often the +actual design changes so this is very + + align:start position:0% +actual design changes so this is very + + + align:start position:0% +actual design changes so this is very +much like the + + align:start position:0% +much like the + + + align:start position:0% +much like the +garage case except it's now applied into + + align:start position:0% +garage case except it's now applied into + + + align:start position:0% +garage case except it's now applied into +a much more complicated situation + + align:start position:0% +a much more complicated situation + + + align:start position:0% +a much more complicated situation +thirdly + + align:start position:0% +thirdly + + + align:start position:0% +thirdly +uh we said okay given that we have the + + align:start position:0% +uh we said okay given that we have the + + + align:start position:0% +uh we said okay given that we have the +demand scenarios let's think about + + align:start position:0% +demand scenarios let's think about + + + align:start position:0% +demand scenarios let's think about +having a flexible design that responded + + align:start position:0% +having a flexible design that responded + + + align:start position:0% +having a flexible design that responded +to the demand as it happened so if it + + align:start position:0% +to the demand as it happened so if it + + + align:start position:0% +to the demand as it happened so if it +was growing well uh transportation user + + align:start position:0% +was growing well uh transportation user + + + align:start position:0% +was growing well uh transportation user +uses were ballooning and going way up + + align:start position:0% +uses were ballooning and going way up + + + align:start position:0% +uses were ballooning and going way up +then we add more capacity if + + align:start position:0% +then we add more capacity if + + + align:start position:0% +then we add more capacity if +people weren't using it we would not do + + align:start position:0% +people weren't using it we would not do + + + align:start position:0% +people weren't using it we would not do +it and so we now had a design two + + align:start position:0% +it and so we now had a design two + + + align:start position:0% +it and so we now had a design two +designs one is thinking that we + + align:start position:0% +designs one is thinking that we + + + align:start position:0% +designs one is thinking that we +had flexible module designs but we are + + align:start position:0% +had flexible module designs but we are + + + align:start position:0% +had flexible module designs but we are +we're going to do all the plan in one + + align:start position:0% +we're going to do all the plan in one + + + align:start position:0% +we're going to do all the plan in one +place and the second one is say okay + + align:start position:0% +place and the second one is say okay + + + align:start position:0% +place and the second one is say okay +let's suppose it is possible and could + + align:start position:0% +let's suppose it is possible and could + + + align:start position:0% +let's suppose it is possible and could +be desirable to actually move some of + + align:start position:0% +be desirable to actually move some of + + + align:start position:0% +be desirable to actually move some of +the capacity to it so we had a more + + align:start position:0% +the capacity to it so we had a more + + + align:start position:0% +the capacity to it so we had a more +limited version of only about the timing + + align:start position:0% +limited version of only about the timing + + + align:start position:0% +limited version of only about the timing +and + + align:start position:0% +and + + + align:start position:0% +and +a second version of the design with + + align:start position:0% +a second version of the design with + + + align:start position:0% +a second version of the design with +timing and locational choices + + align:start position:0% +timing and locational choices + + + align:start position:0% +timing and locational choices +and + + align:start position:0% +and + + + align:start position:0% +and +then we were thinking about overall + + align:start position:0% +then we were thinking about overall + + + align:start position:0% +then we were thinking about overall +calculating the value of flexibility the + + align:start position:0% +calculating the value of flexibility the + + + align:start position:0% +calculating the value of flexibility the +kind of scale factor + + align:start position:0% +kind of scale factor + + + align:start position:0% +kind of scale factor +and the sensitivity analysis \ No newline at end of file diff --git a/7mcSMG0-3FU.txt b/7mcSMG0-3FU.txt new file mode 100644 index 0000000000000000000000000000000000000000..2d53834ba4d59ff400dfae7da3b0353cf407ab66 --- /dev/null +++ b/7mcSMG0-3FU.txt @@ -0,0 +1,2470 @@ +The following content is +provided under a Creative + +Commons license. + +Your support will help MIT +OpenCourseWare continue to + +offer high quality educational +resources for free. + +To make a donation or view +additional materials from + +hundreds of MIT courses visit +MIT OpenCourseWare at + +ocw.mit.edu. + +PROFESSOR: OK, let's +get started. + +Why doesn't everyone go ahead +and take 10 more seconds on + +this clicker question. + +It should look familiar. + +You were pretty split on this +question on Friday, so we're + +hoping after learning a little +bit more about delta g of + +formation, we have at +least one direction + +that wins out here. + +OK, great. + +So now we're up to 85% of you, +and hopefully in just a minute + +we'll be up to a 100%. + +But if delta g of formation here +is less than zero, that + +means we're talking about a +spontaneous reaction when we + +form the compound. + +So if it spontaneously forms the +compound, that must mean + +that the compound is +going to be stable + +relative to its elements. + +So that's kind of the last thing +we went over in terms of + +topics on Friday, and we'll +pick up right there today. + +All right. + +Here we have our notes for +today, so reminder exam 2 is + +on Wednesday -- + +I don't think I need to +remind anyone of that. + +But just please, don't come to +this room, make sure that you + +go to Walker to take the exam. + +And also if you have any +questions or you feel like + +there's anything you don't +understand, I have office + +hours today from 2 to +4 in my office. + +Your TAs have also all moved +their office hours so they + +fall before the exam. + +So make sure you get any of +your questions addressed + +before you're trying to +sit there and figure + +it out in exam time. + +All right, so today we're going +to pick up where we left + +off on thermodynamics, so that +was talking about free energy + +of formation. + +After that we're going to talk +a little bit more about the + +effect of temperature +on spontaneity. + +We touched upon this on Friday, +but we're going to + +formalize exactly in which cases +temperature can or can + +not affect whether a reaction +is spontaneous or + +non-spontaneous. + +Then we're going to look a +little bit into thermodynamics + +and biological systems. + +Two examples that I wanted to +talk about were ATP coupled + +reactions -- those are very +important in biology. + +And also, thinking about the +idea of hydrogen bonding, + +we're going to combine our +thoughts on bond enthalpies, + +and also our ideas of bonding +that we had from thinking + +about covalent and +ionic bonds. + +All right, so let's finish +up first with + +free energy of formation. + +So as 85% of you just told me, +when we have a case where + +delta g of formation is less +than zero, what we're talking + +about here is a compound that +is thermodynamically stable + +relative to its elements. + +So that means we know the +inverse as well, which is when + +we're talking about a case where +delta g is now greater + +than zero, the compound is going +to be thermodynamically + +unstable relative +to its elements. + +So any time you're looking at +delta g of formation, just + +remember to think about this +is just the delta g of a + +reaction where you're +forming a compound. + +So it should make sense that if +it's negative, it's going + +to be spontaneous and you're +going to have a stable + +compound here. + +So we could look at any number +of examples, really we could + +pick any compound to look at, +but up on the screen here I'm + +just putting the compound, the +formation of benzene, we've + +looked at benzene a lot. + +So benzene has a delta +g of formation of 124 + +kilojoules per mole. + +Is benzene stable or unstable +compared to its elements? + +I can't really tell the +difference between stable and + +unstable when you say it, +so everyone start at + +the same time, go. + +STUDENT: Unstable. + +PROFESSOR: OK, excellent. + +Benzene is unstable compared +to its elements. + +So that means the reverse +reaction here is going to be + +stable -- or the reverse +reaction is going to be + +spontaneous where we +actually have the + +decomposition of benzene. + +So when we're seeing this, when +we're seeing that the + +reverse reaction is spontaneous, +a question that + +might immediately come to us is +well, why did we just spend + +all the time talking about +benzene because clearly + +benzene's just going to +break down, right. + +Why do we form benzene and not +have it immediately decompose + +into its elements. + +Thermodynamically that is what +should happen and it is what + +does happen, but the reality +is that this reaction, this + +decomposition of benzene is +actually very, very slow. + +It's so slow that, you know we +use benzene all the time in + +organic reactions, we don't see +it break down even when we + +heat it up, is because +even though this is + +thermodynamically a +non-spontaneous reaction to + +form benzene, it's very slow for +the actual decomposition + +of benzene to occur. + +So this is just another case, +and I'll keep saying this, and + +when Professor Drennan starts +talking about kinetics, she'll + +keep repeating this as well. + +What we want to keep in mind +is that delta g tells us + +whether a reaction will happen +or whether it won't happen. + +It tells us absolutely nothing +about how long it takes for + +that reaction to happen. + +It tells us nothing about the +rate of the reaction. + +We'll keep seeing examples of +this, so hopefully no one will + +be confused by the time +we do get to kinetics. + +So if we're talking about +calculating delta g for any + +reaction, now we actually have +several ways to do it. + +The first way is very analogous +to thinking about + +delta h for the reaction. + +We can just look up a +table where we have + +delta g as a formation. + +So we can take the sum of the +delta g of formation of the + +products, and subtract from it +the delta g of formation of + +the reactants. + +We also have another way if +maybe we don't have that + +information available to us. + +We can also take a look at using +this reaction or this + +equation right here, which is +telling us that delta g of a + +reaction is equal to the +change in enthalpy + +minus t delta s. + +So that tends to be very +helpful, especially when we + +want to take into consideration +temperature. + +So let's take into consideration +temperature. + +We've done this a little bit so +far, but let's really take + +a look at some reactions where +temperature's going to make a + +big difference. + +So the reaction we're going +to look at here is the + +decomposition of sodium +bicarbonate, or sodium bicarb + +here, and it decomposes it into +sodium carbonate, plus c + +o 2, carbon dioxide, +and water. + +So we can think about +calculating that delta g of + +this reaction. + +I'll tell you that the change in +enthalpy, this is actually + +an endothermic reaction. + +It requires heat. + +It's plus 135 . + +6 kilojoules per mole. + +So let's go to a clicker +question and I want you to + +pick out from several choices +which of the changes in + +entropy seem reasonable +to you here. + +So what would you predict +the delta s for + +this reaction to be? + +All right, let's do 10 +more seconds on that. + +OK, so we've got the majority, +but not everyone. + +So let's take a look at why this +is the correct answer, + +that it should be plus 0.334 . + +If we're going from 2 moles of +solid, to 1 mole of solid, + +plus 2 moles of gas, are +we increasing or + +decreasing the disorder? + +STUDENT: [INAUDIBLE] + +PROFESSOR: We're increasing +the disorder. + +If we're getting to a more +disordered state, then we're + +going to have a positive +change in entropy. + +We're going to increase +the disorder. + +The only one with a positive +delta s is this choice here. + +So if we switch back to our +notes, we can see that, in + +fact, so what we see is that +it's 0.334 kilojoules per k + +per mole is our delta s, so we +can go ahead and calculate our + +delta g for the reaction, +so we're just plugging + +in our delta h. + +So our delta h is 135 . + +6. + +And we're talking about to start +with let's talk about + +room temperature. + +So 298 k times 0.334 . + +So what we end up having for the +delta g of our reaction is + +that its 36 . + +1 kilojoules per mole. + +So this is at room +temperature. + +So is our reaction spontaneous +or non-spontaneous at room + +temperature? + +STUDENT: Non-spontaneous. + +PROFESSOR: Non-spontaneous. + +All right, but let's take +a look at a different + +temperature. + +For example, let's look +at baking temperature. + +So if we think about baking +cookies, we maybe bake them at + +350 degrees fahrenheit, so that +would be 450 kelvin -- + +our ovens are usually set to +fahrenheit and not kelvin. + +So if we think about this +reaction that this + +temperature, first of all let +me point out why we would be + +talking about baking +cookies for this + +particular reaction here. + +Does anyone know what another +name for sodium bicarb is? + +STUDENT: [INAUDIBLE] + +PROFESSOR: Yeah, it's +just baking soda. + +So this is the reaction that +causes your cookies or your + +cakes to actually rise. + +So we're producing gas here, and +when we're producing that + +gas when this sodium bicarb +decomposes, we're forming + +these pockets of gas +in our baked goods. + +So if we bake our cookies at +room temperature, obviously, + +they don't bake and they also +don't rise because the sodium + +bicarb, clearly it was +non-spontaneous at room + +temperature, this reaction +just doesn't happen. + +But if we take a look at baking +temperature now, we're + +going to plug in this new +temperature, which is 450 k, + +and plug this into our +delta g reaction. + +What we find is now our delta +g for the reaction + +is negative 14 . + +7 kilojoules per mole. + +So in this case, we are dealing +with a spontaneous + +reaction, which is good, because +this means that when + +we put our cookies in and we +turn it to 350 fahrenheit or + +450 k, the baking soda will +decompose and we'll got our + +cookies to rise a little bit. + +All right, so one thing that I +want you to notice when we + +were talking about the case +with the decomposition of + +sodium bicarb is that the delta +h for that reaction and + +the delta s, they both +had the same sign. + +And something that you can keep +in mind in general is any + +time that both delta h and delta +s have the same sign, + +it's actually possible to switch +from spontaneous to + +non-spontaneous or vice versa +just by changing the + +temperature of the reaction. + +And we can think about +this graphically. + +If we assume that delta h and +delta s are independent of + +temperature, which is a good +assumption to a first + +approximation, in this case we +find that the delta g of the + +reaction is the linear function +of the temperature. + +So that means we can go ahead +and graph what we saw for the + +case of baking soda. + +So our first point here was +that we saw at room + +temperature, about 298 k, the +delta g was positive, it was + +36 kilojoules per mole. + +We also saw that once we +heated it up to baking + +temperature, we actually had the +delta g now at negative 15 + +kilojoules per mole. + +So since this is linear, we can +actually draw a straight + +line right through here, and +we can think about the fact + +that we have this temperature +here where anything below this + +temperature has a positive delta +g, and anything above + +this temperature is going to +have a negative delta g. + +And let's actually think about +the fact that this is a line + +and see what our slope and our +y-intercept is going to mean. + +We can say that delta g is equal +to negative delta s t + +plus delta h, if we want to put +it in the formation of the + +equation for line. + +So what this tells us is that +our slope is going to be + +negative delta s here, and +if we think about our + +y-intercept, that's going to be +the change in enthalpy for + +the reaction. + +So again, what I want to point +out is that any time we're at + +a temperature that's lower +than this change in + +temperature here, we're going +to find that delta g is + +greater than zero, and we're +going to be dealing with a + +non-spontaneous reaction. + +However, if we move our +temperature up and up and up + +so we go across the graph this +way, eventually we'll hit a + +point where if we're above that +temperature, we'll find + +that delta g is less than +zero, and now we have a + +spontaneous reaction. + +So we can actually think about +what this temperature is. + +We can call this T star. + +This is the temperature at which +our reaction switches, + +whether it's spontaneous +or non-spontaneous. + +And if you're thinking about +trying to get a reaction to + +go, it's very important to be +able to calculate what this + +temperature is. + +A lot of times in organic +chemistry laboratories, they + +need to heat up reactions -- +part of why they do that is + +kinetics, but the other part is +sometimes they need to make + +a reaction go from being +non-spontaneous to + +spontaneous. + +So let's think about how to +calculate T star or this + +change in temperature. + +So we're talking about this +threshold temperature, so + +we're talking about where delta +g is going to be equal + +to zero, because if we set delta +g equal to zero, we know + +that anything on one side of +that temperature is going to + +be spontaneous, and the other +side is going to be + +non-spontaneous. + +So if we do this, we can just +rewrite our reaction, delta g + +equals delta h minus t delta s, +and let's plug in our zero + +for delta g there, and now +rearrange our reaction so that + +we're talking about this +threshold temperature. + +So that T star is just going to +be equal to the change in + +enthalpy divided by the +change in entropy. + +So it's very easy for us to +calculate, so let's go ahead + +and do this for the case +with baking soda. + +And for baking soda what we saw +was that delta h was 136 + +kilojoules per mole, and the +change in entropy was 0.334 + +kilojoules per k mole. + +And that means if we do that +simple division, then what we + +end up as our temperature +star is 406 kelvin. + +So basically, what this tells us +is if we tried to bake our + +cookies below 406 kelvin they +would not rise, if we bake + +them above 406 kelvin they +will rise because this + +reaction is now spontaneous. + +All right, so this was a case +where we had seen that the + +delta h and the delta s both +had a positive value. + +But let's take a look at what +happens when now delta h and + +delta s are both negative. + +So we can think about this just +by plotting it on our + +graph again -- we don't have +actual values, but we can + +think about what the +sign should be. + +So if we talk about our zero +point where temperature is + +absolute zero, if we have a +positive, or excuse me, if we + +have a negative delta h now +and we're at temperature + +equals zero, what is delta +g going to be? + +Negative or positive? + +Yeah, it's going +to be negative. + +So if we have negative delta h +and we're at temperature of + +zero, our s term completely +falls out, so we're definitely + +going to start with a +negative delta g. + +As we increase the temperature +higher and higher, at some + +point that delta s term is going +to become greater than + +our delta h term, so at some +point we're going to flip to + +where the reaction has now +a positive delta g. + +So you can draw this into your +graphs in your notes where + +we're going to start, in this +case if delta g is negative + +where delta g starts negative, +and then when it hits that + +threshold temperature, +anything above that + +temperature is going +to be positive. + +So if we had actual numbers we +could plug those into our + +graph, but we should be able to +understand what the general + +trend is going to be even in a +hypothetical case where we're + +just dealing with is it positive +or is it negative. + +So what we see is that below +this temperature, we have a + +spontaneous reaction, and above +this temperature we have + +a non-spontaneous reaction. + +That was flipped from the case +where we had delta h and delta + +s both be positive. + +All right, so let's actually +summarize what all of our four + +different scenarios could be +if we're dealing with delta + +h's and delta s's. + +So to start with, why don't you +tell me what you think if + +we have a reaction where we have +a negative delta h and we + +have a positive delta s, do you +think that this will be a + +reaction that's never +spontaneous, always + +spontaneous, or will this be one +of these cases where the + +spontaneity depends +on temperature? + +All right, let's take 10 +more seconds on this. + +OK, great. + +So most of you got it. + +So let's go back to the slides +and think a little bit about + +why this is. + +So, this case is always +spontaneous, because in this + +case we have a negative delta +h, which contributes to a + +negative delta g, and a positive +delta s, but since + +the equation says minus t delta +s, that means a positive + +delta s is also going +to contribute to a + +negative delta g. + +So regardless of what the +temperature is, we're going to + +have a spontaneous reaction. + +So we say this is always +spontaneous -- delta g is less + +than zero at all temperatures. + +All right. + +So let's look at the reverse +case here where delta h is now + +greater than zero, and delta +s is less than zero. + +Is this always, never, or +sometimes spontaneous? + +STUDENT: [INAUDIBLE] + +PROFESSOR: Nope. + +So, this is going to be never +spontaneous in this case. + +So for the same reason, because +delta h is greater + +than zero, that contributes to +a positive delta g, and delta + +s being negative also +contributes to a + +positive delta g. + +So we'll say again, that this +delta g is greater than zero + +at all temperatures. + +All right, so now we have a case +where delta h is greater + +than zero and delta s is greater +than zero as well. + +Is this going to be always, +never, or sometimes + +spontaneous? + +STUDENT: Sometimes. + +PROFESSOR: Sometimes, good. + +So, even before thinking, you +can just remember if the signs + +are the same, we can +have a dependence + +on temperature here. + +So what we find is that this +is sometimes spontaneous. + +So we can think about +when this happens. + +Would it be when the actual +temperature is greater or less + +than that threshold +temperature? + +STUDENT: [INAUDIBLE] + +PROFESSOR: All right, so I +heard a lot of people say + +greater than. + +It's greater than, because when +it's greater than that + +threshold temperature, that +means that the delta s term is + +the one that's going to actually +sort of take over, + +it's going to be at some point +greater than the delta h term. + +The delta h is going to be +making the delta g positive. + +That means it would make it +non-spontaneous, but once + +delta s gets large enough, +that's going to override, and + +now we're going to have a +negative delta g only when the + +temperature is above that +threshold temperature. + +So similarly, when we see that +delta h is negative and delta + +s is negative, this is also +going to be sometimes + +spontaneous, and specifically, +it will be spontaneous or + +delta g will be less than 0 when +the temperature is less + +than that threshold +temperature. + +All right, so you should be able +to look at any situation + +where you have or you figure +out or you calculate the + +enthalpy and the enthropy change +in the reaction, and + +you should right away, before +doing any calculations, be + +able to know is this always +spontaneous, is this never + +spontaneous, or is this +something where I'm going to + +need to really take +temperature into + +consideration. + +And if I do, you can actually +calculate what that + +temperature is going to +be where you flip from + +spontaneous to non-spontaneous +or vice versa. + +All right, so shifting gears a +little bit, let's take a look + +at a few examples where it's +important to think about + +thermodynamics and biological +systems. + +So there's two things I +particularly want to focus on. + +So the first is the idea of +ATP coupled reactions. + +So this is really important, +because when we're talking + +about biological reactions, a +lot of the reactions that take + +place in our body are actually +non-spontaneous, so + +energetically we figure that the +delta g for this reaction + +is actually positive. + +So I just show a schematic +biological reaction here where + +we have some molecule that's +broken up into + +two building blocks. + +So let's say, for example, +this has a delta g that's + +greater than zero. + +We need to think about how it is +that our body can actually + +make this reaction happen. + +And the way that it does this +is that it takes the + +hydrolysis of ATP, and the +hydrolysis of ATP is what's + +called that it's coupled to this +non-spontaneous reaction. + +And when you have a spontaneous +reaction coupled + +to a non-spontaneous reaction, +you can potentially drive the + +reaction in the forward +direction. + +Remember the hydrolysis of ATP +is spontaneous, so what we're + +doing in this case is we're +taking a spontaneous reaction + +where we give off energy, and +we're coupling it to a + +non-spontaneous reaction +that requires energy. + +So what we will hope is when +we add up the total energy + +changes between these two +reactions, if the sum of those + +two is a negative delta g total, +now we can have this + +whole process move in the +forward direction. + +So let's take a look at thinking +about what we can do + +in terms of a coupled +reaction. + +The first thing we need to do if +we're thinking about using + +the hydrolysis of ATP is +actually calculate what the + +delta g for the reaction of +ATP hydrolysis is, and I + +picked 310 kelvin because +that's the + +temperature of our bodies. + +So again, this reaction is +taking adenosine triphosphate + +that has three phosphate groups +and hydrolyzing it, so + +reacting it with water +to form ADP plus + +phosphate plus acid here. + +So I'll tell you that the delta +h of this reaction is + +negative 24 kilojoules +per mole. + +This is what we actually +calculated in class on Friday. + +And that the delta s is plus 22 +joules per k, per mole, so + +we can go ahead and calculate +what this delta g is here. + +So the delta g of this overall +reaction is just going to be, + +of course, delta h minus t delta +s, and our delta h is + +minus 24 kilojoules per mole, +and we'll subtract 310 + +kelvin times 0 . + +022 kilojoules over k mole. + +So if we do this, what we end +up getting is a delta g of + +negative 31 kilojoules +per mole of ATP. + +All right, so again, this is +good, we got a negative + +number, that's what +we were expecting. + +So that means that we will have +energy available to use + +if we hydrolyize ATP +and couple it to + +another reaction here. + +So what we saw for our +delta g, negative 31 + +kilojoules per mole. + +All right, so let's talk about +a reaction that is a ATP + +coupled reaction, and there's +just tons of examples of this + +in our body. + +One I picked because it has to +do with glucose, which we have + +talked so much about, is the +conversion of glucose to + +glucose 6 p. + +So 6 p -- p just stands for a +phosphate group here, so what + +we're doing is taking, if we +numbered the glucose carbons, + +this would be carbon number +six, and we're putting a + +phosphate group on carbon +number six. + +So first of all, why would our +body need to do this reaction? + +It turns out that glucose, +we know that we + +use glucose for energy. + +Glucose is somewhat apolar, so +it can actually move in and + +out of our cells, because +our cell walls, + +those are very greasy. + +So what we're actually doing +here is we're putting a + +charged molecule onto +the glucose. + +There's two negative charges in +a phosphate group, this is + +going to make sure that +our glucose is now + +it's very polar molecule. + +And now that we have a very +polar molecule, we're not + +going to be able to have +the glucose move in + +and out of the cell. + +So we keep it in our cell +by putting this + +phosphate group on it. + +That's why we want to do this +reaction, but let's think + +about the energy of +actually doing it. + +And it turns out that this +requires energy. + +The delta g for this reaction +is 17 kilojoules per mole. + +All right, so that could be a +problem if our body had not + +come up with a way to solve it, +which it has, and what it + +actually does is it couples this +reaction here with the + +conversion of ATP into ADP. + +And we just calculated that that +has a delta g of negative + +31 kilojoules per mole. + +So this means we can think about +delta g total, and by + +total we mean of this overall +process here. + +So that's just equal to 17, +and we're adding it to the + +other delta g, which +is negative 31. + +So we get an overall delta g for +this process of negative + +14 kilojoules per mole. + +All right, so that's one really +simple example just to + +illustrate to you how these ATP +coupled reactions work. + +Some ATP coupled reactions +require one molar equivalent + +of ATP, some require +a lot more. + +But essentially, the +idea is the same. + +We have this reaction that's +energetically unfavorable that + +we couple with an + +energetically favorable reaction. + +So, quite literally, this is +what we mean when we talk + +about ATP as being the energy +currency for the cell. + +We spend some ATP in order to +get these non-spontaneous + +reactions to go. + +All right, so I also want to +talk to a little bit about + +hydrogen bonding. + +This also is a topic that deals +with the thermodynamics, + +and it also is related to the +ideas that we talked about + +before in terms of +thinking about + +different types of bonds. + +So if we talk about a hydrogen +bond, a hydrogen bond, first I + +just want to be really clear, +is not a covalent bond. + +So this h x bond here is a +covalent bond, this is not a + +hydrogen bond. + +But a hydrogen bond can form +when you have a partial + +positive on a hydrogen, and +you have what's called a + +hydrogen bond donor atom, which +has a partial negative + +on it, and also has +a lone pair. + +Typically this y atom will be +on a separate molecule. + +And what happens is you have +that Coulombic attraction + +between the partial positive +on the hydrogen and the + +partial negative on this +hydrogen bond donor atom. + +So what you form between them is +a hydrogen bond, and you'll + +notice that I drew it +as a dashed line. + +H bonds or hydrogen bonds are +drawn either as dashed lines + +or as dotted lines, and +they're done so to + +differentiate them from covalent +bonds, which we draw + +with this straight line here. + +So let's think about what +can form hydrogen bonds. + +First of all, there's a +requirement for what this h x + +bond can be. + +It has to be a really +electronegative atom in this x + +here, because we need to we +need to form that partial + +positive on the hydrogen, which +means that the atom that + +it's covalentally bonded to +needs to be pulling away some + +of that electron density from +the hydrogen, such that we + +have a delta positive +on a hydrogen atom. + +Similarly, the same atoms are +what can be the y here, so it + +can either be a nitrogen or +an oxygen or a fluorine. + +So these are the only +hydrogen bond donors + +that can form h bonds. + +And we can think about the +reason for this and the reason + +is pretty straightforward. + +We need to have a small atom, +but it also needs to be really + +electronegative. + +This should make sense because +we need to have this partial + +negative charge here to have +that Coulomb attraction. + +And the other requirement is +that we definitely need to + +have that lone pair of electrons +so it can actually + +interact in this hydrogen +bond here. + +So let's take a look at an +example of a hydrogen bond, + +and that's between two +water molecules. + +So let's go ahead and re-draw +our water molecules -- they're + +just kind of randomly +oriented there. + +But let's re-draw them as if +they were going to have a + +hydrogen bond between them. + +And one thing I want to point +out about hydrogen bonds is + +that they're strongest when you +actually have all three + +atoms in a straight line like +this, because it keeps the + +dipoles the strongest, so the +partial positive here and the + +partial negative here +can interact. + +So let's re-draw our water +molecules like that. + +So we have our first water +molecule here, and let's say + +we're going to be talking about +this hydrogen in terms + +of hydrogen bonding. + +Obviously, we have four +hydrogens up there that can + +take place or take part in h +bonding, but we're just going + +to focus on this one here. + +So that means we want our +straight line to be something + +like this to our +second oxygen. + +So let's draw the hydrogens on +this water molecule as well. + +All right, so thinking about +what the Lewis structure of + +water is, how many lone +pairs do we have + +on this oxygen here? + +STUDENT: [INAUDIBLE] + +PROFESSOR: Two lone +pairs, great. + +So let's draw those in, +and let's draw these + +lone pairs in as well. + +All right, and we're going to +be talking about these two + +atoms in terms of our hydrogen +bond, so does this have a + +delta plus or a delta +negative on it? + +Delta plus. + +So this is a polar bond here, +this o h bond, so we have a + +delta plus on our hydrogen, and +we have a delta minus on + +our oxygen. + +So these also have delta +plusses, of course, and this + +also has a delta minus. + +So because these two can +interact and they're lined up + +to do so, what we can do is we +can draw a hydrogen bond right + +in between this hydrogen and +this oxygen atom here. + +So again, I pointed out that, +in fact, hydrogen bonds are + +not as strong as +covalent bonds. + +Since they're not as strong, if +you remember thinking about + +the relationship between bond +strength and bond length, + +would you expect a hydrogen bond +to be longer or shorter + +than a covalent bond? + +STUDENT: Longer. + +PROFESSOR: Good, OK, it +should be longer here. + +So this is our longer bond +because it's our weaker bond. + +They're not held together +as tightly. + +All right, so this is an example +of an intermolecular + +hydrogen bond, it's between +two different molecules. + +Hopefully, you can also see that +if we're focusing on any + +single one water molecule, we +could also form hydrogen bonds + +between other water molecules +with either of these two + +hydrogens as well, and also with +our other lone pair here. + +So any water molecule can +actually form four different + +hydrogen bonds. + +All right, so let's talk a +little bit about these + +hydrogen bonds in terms of their +bond enthalpies here. + +I said that they were weaker +than covalent bonds, so let's + +look at a few comparisons +here. + +So we can look at an h o +hydrogen bond versus an h o + +covalent bond. + +And what we find is that the +bond enthalpies in kilojoules + +per mole, it's 20 kilojoules per +mole for a hydrogen bond + +versus 463 kilojoules per mole +for a covalent bond. + +So we're not talking about +just a little bit weaker, + +we're talking about much, +much weaker for the + +hydrogen bonds here. + +Similarly, if we look at +nitrogen, for nitrogen + +hydrogen bonds, if we have an +o h bound to a nitrogen, + +that's 29 kilojoules per mole. + +If it's an n h hydrogen bound +to a nitrogen, that's 14 + +kilojoules per mole, and if +we're talking about an h n + +covalent bond, now we're +talking about 388 + +kilojoules per mole. + +All right, so again what we see +in these cases is that the + +hydrogen bonds are much, +much weaker. + +They tend to be as low as 5% of +what the covalent bond is, + +so this is actually much weaker +than any kinds of bonds + +we have within molecules, but +it's also the strongest type + +of bond that we can +have between + +two different molecules. + +And one thing that you find as +in the case of water, is when + +you have lots of hydrogen bonds +between molecules it + +changes the property of, for +example, water here. + +It makes the boiling point much, +much higher than you + +might expect if you looked at +the other properties, because + +you have to actually break apart +all of these individual + +hydrogen bonds, and even though +it's not that much + +energy for one individual +hydrogen bond, once you get a + +huge number of hydrogen bonds, +you're talking about huge + +energies here. + +So let's look at some examples +of where we see hydrogen bonds + +in biological processes. + +First thinking about proteins, +they're absolutely hugely + +important in proteins. + +And in proteins, we're talking +about a molecule that's so + +large that you don't just see +h bonds in between two + +different molecules, what you +actually see is what's called + +intramolecular hydrogen bonding, +so hydrogen bonding + +within the protein +molecule itself. + +And hydrogen bonding is +incredibly important, it, in + +fact, is the shape of a protein, +which I'm just + +showing an example here, histone +deacetylase, and the + +histone deacetylase molecule +actually has just countless + +hydrogen bonds in here, and +the hydrogen bonds largely + +govern the shape of +the molecule. + +So, if you're thinking about any +protein that has a shape, + +so for example, we see these +ribbon structures here, + +they're called alpha helices, +you can see some arrows, which + +are just like a sheet structure +or beta sheets, that + +actual shape is stabilized and +formed in the first place by + +just many, many hydrogen bonds +within the protein being in a + +correct orientation that allows +for this particular + +shape to be stabilized. + +And we know that shape is so +important when we're talking + +about proteins, and that's +because the actual shape of + +the protein governs the +interaction with other + +proteins or other +small molecules. + +The shape of the protein is +very important in terms of + +positioning the specific atoms +that are involved in the + +chemistry that the enzyme +carries out being in the + +correct position. + +So hydrogen bonds are very + +important in terms of proteins. + +We can also think of them +in terms of sugars or + +polysaccharides. + +This is a nice dramatic example, +thinking about the + +structure of a protein is a +very microscopic way of + +thinking about hydrogen +bonding. + +If we want to take it to the +macroscopic level, we can talk + +about h bonding in trees. + +So if we're talking about trees, +trees are made up -- a + +major part of a tree is the +polysaccharide cellulose. + +So that's shown right here. + +Cellulose is a chain of glucose + +molecules linked together. + +It can be as many as 1,000 or +more glucose molecules linked + +together covalentally. + +But what actually happens to +those individual chains is + +that if you look at this picture +here, all those dotted + +lines are actually +hydrogen bonds. + +So the individual molecules are +in a much larger chain of + +hydrogen bonded molecules and +they're incredibly rigid. + +You have so many hydrogen bonds +that now it takes a huge + +amount of energy to break +all of these. + +So that accounts for +why wood is such + +a hard, solid material. + +And also, I mean for any plant, +and tree is the most + +dramatic, the structure of +a tree, the macroscopic + +structure, can be explained +by hydrogen bonding. + +It's hydrogen bonds that keep +all of those molecules + +together in the forest +and in trees. + +All right. + +So, that's proteins, that +thinking about sugars. + +We can also talk about +the importance of + +hydrogen bonding in DNA. + +So if you think about the +characteristic DNA double + +helix, hydrogen bonds, we have +in a double helix we have two + +strands of DNA that you can +see are intertwined here. + +And those two strands are +actually held together by + +hydrogen bonding. + +So specifically, it's hydrogen +bonding between what are + +called complimentary bases +within the DNA. + +So, for example, if we look at +guanine and cytosine here, you + +can see that there's several +places, when they're lined up + +like this, where we can +have hydrogen bonds. + +So in terms of thinking about +how these two molecules are + +lined up, how many h bonds +would you expect + +between these two bases? + +Yeah, so it's lined up +that there are three + +that can form here. + +So we have an o h hydrogen bond, +an h n, and then an h o + +hydrogen bond that can form. + +So the other side of +complimentary based pairs are + +AT base pairs, and if you look +at the way these are lined up + +here, how many hydrogen +bonds can form between + +A and T base pairs? + +Yup, so it it's two that +we can form here. + +We have one between the h o, one +between the n h, and you + +see that we've lost this +nitrogen, this n h group here, + +and first of all this would be +too far apart anyway for + +hydrogen bond, but we can't have +a hydrogen bond form when + +we have a carbon h. + +Remember, it has to either be +a nitrogen or an oxygen or a + +fluorine because those are the +atoms that are going to pull + +away enough electron density +from the hydrogen to give it a + +partial positive charge +that it needs. + +So in terms of thinking about +DNA, this is a really neat + +case to consider the actual +thermodynamics or the bond + +enthalpies of the hydrogen +bonds, because, of course, + +does not always stay in it's +double helix -- when we're + +talking about transcription, we +actually need to unzip or + +separate this helix into its +two strands, so each + +individual strand +can be copied. + +So it's really important that +hydrogen bonds are strong + +enough to hold the DNA double +strand together, but that + +they're not so strong that when +you actually pull the + +hydrogen bonds apart to open up +the double strand, that you + +actually, you don't want to +break all of a covalent bonds + +in DNA as well. + +All right, so that's all we're +going to say in terms of + +thinking about thermodynamics +and biological systems. + +Hold on a sec, we have +plenty of time left. + +I want to go over a few +clicker questions. + +I didn't want to give you too +long set of notes, because + +we're switching over to +Professor Drennan's going to + +start lecturing on Friday, so +I thought maybe I shouldn't + +have to have her finish +up with my notes. + +So, Professor Drennan will +continue talking about + +thermodynamics and thinking +about equilibrium, and then + +she'll transition that into +talking about kinetics. + +So that's actually what's going +to start happening after + +the exam on Wednesday. + +But let's take a look, since we +do you have a little bit of + +time left, at a few clicker +questions just to make sure + +everyone has caught what +we've gone over so far. + +And a few reviews for the exam, +and I will have this + +clicker question or one of the +ones following, be a clicker + +question quiz, so make sure you +are still answering these + +questions here. + +So the first one covers what we +went over today, so I want + +you to tell me and try to not +look back in your notes for + +this, for a reaction where you +have a positive enthalpy and a + +negative entropy change, would +you expect this reaction to be + +never, always, or sometimes +spontaneous? + +So let's take 10 seconds +on that, that + +should be pretty fast. + +OK, excellent. + +90% is very good. + +So this should never be +spontaneous, because we both + +have the entropy and the +enthalpy term contributing to + +a positive delta g. + +All right, let's shift gears to +a couple of questions that + +are review for the exam. + +So hopefully, these +will all be very + +straightforward for you now. + +So I want you to think about +bond lengths here, and tell me + +which molecule contains the +shorter nitrogen oxygen bond. + +So, we're comparing n o minus +1, and n o 2 minus 1. + +So if you wanted to get started +on this problem, + +what's the first thing +you should do? + +Yeah, draw some Lewis +structures. + +So that might be a good +place to start in + +thinking about this. + +So I'll do that up here as well, +but don't look if you + +want to try it on your own. + +Remember, the quiz points +come for answering, not + +for getting it right. + +So try doing it on +your own here. + +All right, let's go ahead +and take 10 more + +seconds on this one. + +OK, hold on. + +Don't show the correct answer. + +You know we're going to re-poll +and give you a little + +bit more time to see if we +come to a consensus here. + +So let's take another 30 seconds +or so on this while I + +finish drawing these up here. + +OK, good. + +So we've got 81% have it correct +that in the n o minus + +1 bond here, this is going +to be a double bond. + +STUDENT: What if [INAUDIBLE]. + +PROFESSOR: No. + +It would be a double +bond here. + +So, if you follow just the Lewis +structure rules, and you + +go ahead, you'll find that we +end up having four bonding + +electrons available. + +So you can just go ahead and +plug those in, and you end up + +with this many left. + +If we had a triple bond, then +we would end up having more + +bonding -- or we would end up +using more electrons than we + +have available for +bonding here. + +All right, so we have a double +bond in the case of n o. + +What is this bond that +we have here? + +Yup, so it's actually a 1 . + +5 bond. + +What is this bond that +we have here? + +STUDENT: [INAUDIBLE] + +PROFESSOR: All right, +so we have two 1 . + +5 bonds in this case, how +come these are 1. + +5 and not, for example, +a double bond? + +STUDENT: [INAUDIBLE] + +PROFESSOR: Great, so +that's the key. + +Even though we have double +bonds in each of these + +structures, in this case here, +we have resonance, so it's + +turns out to be, in +fact, two 1 . + +5 bonds. + +So since this is the double +bond, it's going to be the + +stronger bond. + +Since it's the stronger bond, +it's also going to be the + +shorter bond. + +So make sure you can make those +relationships between + +bond strength and bond length +and thinking about if you have + +resonance or you don't +have resonance in + +a particular situation. + +All right, let's try one more +clicker question here. + +We'll have this be the +last one for you. + +So this is one that hopefully +you'll all get right, because + +we've gone over this again and +again both in class and + +recitation. + +So let's talk about the +hybridization of the specific + +carbon and oxygen atoms in ATP, +so I want you to go ahead + +and tell me what these +hyrbridizations are + +for these two atoms. + +OK, let's take 10 more seconds +here, get those + +final answers in. + +OK, good, so 83% of +you got this. + +Let's take a look at why. + +So carbon a is bonded to three +things, but it is bonded to no + +lone pairs, so we need to have +it be three hybrid orbitals, + +so it's s p 2. + +And oxygen is bonded to two +atoms plus two lone paris. + +So we need four hybrid +orbitals or s p 3. + +All right, so this was your quiz +question, so as long as + +you answered it, you got your +quiz points for today. + +And you can get going a little +bit early today and finish + +studying for this exam. \ No newline at end of file diff --git a/7w1qqEUwn2k.txt b/7w1qqEUwn2k.txt new file mode 100644 index 0000000000000000000000000000000000000000..2c5dfde1df75f97637278cf59b58446c663f5036 --- /dev/null +++ b/7w1qqEUwn2k.txt @@ -0,0 +1,2616 @@ +align:start position:0% + +hi welcome back to recitation in lecture + + align:start position:0% +hi welcome back to recitation in lecture + + + align:start position:0% +hi welcome back to recitation in lecture +you've been learning about Stokes + + align:start position:0% +you've been learning about Stokes + + + align:start position:0% +you've been learning about Stokes +theorem and I have a nice exercise on + + align:start position:0% +theorem and I have a nice exercise on + + + align:start position:0% +theorem and I have a nice exercise on +Stokes theorem for you here so I'm going + + align:start position:0% +Stokes theorem for you here so I'm going + + + align:start position:0% +Stokes theorem for you here so I'm going +to let F be this field that I've written + + align:start position:0% +to let F be this field that I've written + + + align:start position:0% +to let F be this field that I've written +just above me so it's 2xz minus 2 y + + align:start position:0% +just above me so it's 2xz minus 2 y + + + align:start position:0% +just above me so it's 2xz minus 2 y +comma 2 YZ + 2x comma x^2 + y^2 + z^2 + + align:start position:0% +comma 2 YZ + 2x comma x^2 + y^2 + z^2 + + + align:start position:0% +comma 2 YZ + 2x comma x^2 + y^2 + z^2 +and I've got C so C is this kind of + + align:start position:0% +and I've got C so C is this kind of + + + align:start position:0% +and I've got C so C is this kind of +complicated looking curve here so it + + align:start position:0% +complicated looking curve here so it + + + align:start position:0% +complicated looking curve here so it +sort of dips up and down and back around + + align:start position:0% +sort of dips up and down and back around + + + align:start position:0% +sort of dips up and down and back around +and it's but what you know about it the + + align:start position:0% +and it's but what you know about it the + + + align:start position:0% +and it's but what you know about it the +thing I'm really going to tell you about + + align:start position:0% +thing I'm really going to tell you about + + + align:start position:0% +thing I'm really going to tell you about +it is that it all lies on this on this + + align:start position:0% +it is that it all lies on this on this + + + align:start position:0% +it is that it all lies on this on this +cylinder of radius a uh sorry radius B + + align:start position:0% +cylinder of radius a uh sorry radius B + + + align:start position:0% +cylinder of radius a uh sorry radius B +so it's so C is this curve in the + + align:start position:0% +so it's so C is this curve in the + + + align:start position:0% +so it's so C is this curve in the +cylinder of radius B that wraps around + + align:start position:0% +cylinder of radius B that wraps around + + + align:start position:0% +cylinder of radius B that wraps around +it once but behaves kind of + + align:start position:0% +it once but behaves kind of + + + align:start position:0% +it once but behaves kind of +oddly while it's wrapping around so what + + align:start position:0% +oddly while it's wrapping around so what + + + align:start position:0% +oddly while it's wrapping around so what +I'd like you to do is I'd like you to + + align:start position:0% +I'd like you to do is I'd like you to + + + align:start position:0% +I'd like you to do is I'd like you to +use Stokes theorem to compute the + + align:start position:0% +use Stokes theorem to compute the + + + align:start position:0% +use Stokes theorem to compute the +integral around this curve of f.d now my + + align:start position:0% +integral around this curve of f.d now my + + + align:start position:0% +integral around this curve of f.d now my +hint to you is that for Stokes theorem + + align:start position:0% +hint to you is that for Stokes theorem + + + align:start position:0% +hint to you is that for Stokes theorem +you can use just like you have for + + align:start position:0% +you can use just like you have for + + + align:start position:0% +you can use just like you have for +greens theorem and for Divergence + + align:start position:0% +greens theorem and for Divergence + + + align:start position:0% +greens theorem and for Divergence +Theorem that we've that we've talked + + align:start position:0% +Theorem that we've that we've talked + + + align:start position:0% +Theorem that we've that we've talked +about before you have these extended + + align:start position:0% +about before you have these extended + + + align:start position:0% +about before you have these extended +versions that let you consider more than + + align:start position:0% +versions that let you consider more than + + + align:start position:0% +versions that let you consider more than +one boundary piece so the same thing + + align:start position:0% +one boundary piece so the same thing + + + align:start position:0% +one boundary piece so the same thing +works for Stokes theorem so there's so + + align:start position:0% +works for Stokes theorem so there's so + + + align:start position:0% +works for Stokes theorem so there's so +Stokes theorem works perfectly well when + + align:start position:0% +Stokes theorem works perfectly well when + + + align:start position:0% +Stokes theorem works perfectly well when +you have a when you have a piece of a + + align:start position:0% +you have a when you have a piece of a + + + align:start position:0% +you have a when you have a piece of a +surface with more than one boundary + + align:start position:0% +surface with more than one boundary + + + align:start position:0% +surface with more than one boundary +curve provided you Orient everything + + align:start position:0% +curve provided you Orient everything + + + align:start position:0% +curve provided you Orient everything +correctly so you might think about how + + align:start position:0% +correctly so you might think about how + + + align:start position:0% +correctly so you might think about how +you can use Stokes theorem to replace + + align:start position:0% +you can use Stokes theorem to replace + + + align:start position:0% +you can use Stokes theorem to replace +this complicated curve with a surface + + align:start position:0% +this complicated curve with a surface + + + align:start position:0% +this complicated curve with a surface +integral and an easier to understand + + align:start position:0% +integral and an easier to understand + + + align:start position:0% +integral and an easier to understand +curve and if you can do that then + + align:start position:0% +curve and if you can do that then + + + align:start position:0% +curve and if you can do that then +Computing the other two gives you the + + align:start position:0% +Computing the other two gives you the + + + align:start position:0% +Computing the other two gives you the +third one all right so that's my hint to + + align:start position:0% +third one all right so that's my hint to + + + align:start position:0% +third one all right so that's my hint to +you for for computing this + + align:start position:0% +you for for computing this + + + align:start position:0% +you for for computing this +integral um so why don't you pause the + + align:start position:0% +integral um so why don't you pause the + + + align:start position:0% +integral um so why don't you pause the +video have a go at that come back and we + + align:start position:0% +video have a go at that come back and we + + + align:start position:0% +video have a go at that come back and we +can work on it + + align:start position:0% + + + + align:start position:0% + +together + + align:start position:0% +together + + + align:start position:0% +together +hopefully you had some luck working on + + align:start position:0% +hopefully you had some luck working on + + + align:start position:0% +hopefully you had some luck working on +this problem let's let's talk about it + + align:start position:0% +this problem let's let's talk about it + + + align:start position:0% +this problem let's let's talk about it +so before I left I gave you this hint + + align:start position:0% +so before I left I gave you this hint + + + align:start position:0% +so before I left I gave you this hint +that maybe the thing to do here isn't to + + align:start position:0% +that maybe the thing to do here isn't to + + + align:start position:0% +that maybe the thing to do here isn't to +try and parameterize this curve directly + + align:start position:0% +try and parameterize this curve directly + + + align:start position:0% +try and parameterize this curve directly +and compute the line integral directly + + align:start position:0% +and compute the line integral directly + + + align:start position:0% +and compute the line integral directly +since it's a sort of complicated looking + + align:start position:0% +since it's a sort of complicated looking + + + align:start position:0% +since it's a sort of complicated looking +curve and also since I haven't really + + align:start position:0% +curve and also since I haven't really + + + align:start position:0% +curve and also since I haven't really +given you enough information to do that + + align:start position:0% +given you enough information to do that + + + align:start position:0% +given you enough information to do that +um and instead to think about applying + + align:start position:0% +um and instead to think about applying + + + align:start position:0% +um and instead to think about applying +Stokes theorem so to think about + + align:start position:0% +Stokes theorem so to think about + + + align:start position:0% +Stokes theorem so to think about +applying Stokes theorem what we'd like + + align:start position:0% +applying Stokes theorem what we'd like + + + align:start position:0% +applying Stokes theorem what we'd like +is a nice surface and and with this + + align:start position:0% +is a nice surface and and with this + + + align:start position:0% +is a nice surface and and with this +curve as part of its bounc + + align:start position:0% +curve as part of its bounc + + + align:start position:0% +curve as part of its bounc +um so well what is such a surface well + + align:start position:0% +um so well what is such a surface well + + + align:start position:0% +um so well what is such a surface well +this curve lies all on the cylinder of + + align:start position:0% +this curve lies all on the cylinder of + + + align:start position:0% +this curve lies all on the cylinder of +radius B so a natural choice for a + + align:start position:0% +radius B so a natural choice for a + + + align:start position:0% +radius B so a natural choice for a +surface is to use some piece of this + + align:start position:0% +surface is to use some piece of this + + + align:start position:0% +surface is to use some piece of this +cylinder so maybe we could use the piece + + align:start position:0% +cylinder so maybe we could use the piece + + + align:start position:0% +cylinder so maybe we could use the piece +of the cylinder with this as its upper + + align:start position:0% +of the cylinder with this as its upper + + + align:start position:0% +of the cylinder with this as its upper +boundary so then what might be a natural + + align:start position:0% +boundary so then what might be a natural + + + align:start position:0% +boundary so then what might be a natural +lower boundary to choose well we just + + align:start position:0% +lower boundary to choose well we just + + + align:start position:0% +lower boundary to choose well we just +want to choose something nice and simple + + align:start position:0% +want to choose something nice and simple + + + align:start position:0% +want to choose something nice and simple +right so what's nice and simple well + + align:start position:0% +right so what's nice and simple well + + + align:start position:0% +right so what's nice and simple well +maybe we can choose this this bottom + + align:start position:0% +maybe we can choose this this bottom + + + align:start position:0% +maybe we can choose this this bottom +curve this bottom Circle that's in the + + align:start position:0% +curve this bottom Circle that's in the + + + align:start position:0% +curve this bottom Circle that's in the +plane yal X all right so I'm going to + + align:start position:0% +plane yal X all right so I'm going to + + + align:start position:0% +plane yal X all right so I'm going to +call that that Circle C1 so that's the + + align:start position:0% +call that that Circle C1 so that's the + + + align:start position:0% +call that that Circle C1 so that's the +circle of radius B in the XY plane sorry + + align:start position:0% +circle of radius B in the XY plane sorry + + + align:start position:0% +circle of radius B in the XY plane sorry +not the plane Y equals X the XY plane + + align:start position:0% +not the plane Y equals X the XY plane + + + align:start position:0% +not the plane Y equals X the XY plane +the plane Z equals + + align:start position:0% +the plane Z equals + + + align:start position:0% +the plane Z equals +zero so we've got the the top curve C + + align:start position:0% +zero so we've got the the top curve C + + + align:start position:0% +zero so we've got the the top curve C +we've got this bottom curve C1 now the + + align:start position:0% +we've got this bottom curve C1 now the + + + align:start position:0% +we've got this bottom curve C1 now the +way I've oriented them I've oriented + + align:start position:0% +way I've oriented them I've oriented + + + align:start position:0% +way I've oriented them I've oriented +them both so that they're going + + align:start position:0% +them both so that they're going + + + align:start position:0% +them both so that they're going +counterclockwise as you look down from + + align:start position:0% +counterclockwise as you look down from + + + align:start position:0% +counterclockwise as you look down from +the z-axis so in in that case what does + + align:start position:0% +the z-axis so in in that case what does + + + align:start position:0% +the z-axis so in in that case what does +Stokes theorem say well Stokes theorem + + align:start position:0% +Stokes theorem say well Stokes theorem + + + align:start position:0% +Stokes theorem say well Stokes theorem +says that the integral over the piece of + + align:start position:0% +says that the integral over the piece of + + + align:start position:0% +says that the integral over the piece of +the surface between them let's call it s + + align:start position:0% +the surface between them let's call it s + + + align:start position:0% +the surface between them let's call it s +of curl + + align:start position:0% +of curl + + + align:start position:0% +of curl +F do n with respect to surface area is + + align:start position:0% +F do n with respect to surface area is + + + align:start position:0% +F do n with respect to surface area is +equal to okay so so let's say we can + + align:start position:0% +equal to okay so so let's say we can + + + align:start position:0% +equal to okay so so let's say we can +give it the outward pointing normal say + + align:start position:0% +give it the outward pointing normal say + + + align:start position:0% +give it the outward pointing normal say +in which case C1 will be positively + + align:start position:0% +in which case C1 will be positively + + + align:start position:0% +in which case C1 will be positively +oriented and c will be negatively + + align:start position:0% +oriented and c will be negatively + + + align:start position:0% +oriented and c will be negatively +oriented so this is equal to the line + + align:start position:0% +oriented so this is equal to the line + + + align:start position:0% +oriented so this is equal to the line +integral over + + align:start position:0% + + + + align:start position:0% + +C1 of f dodr minus the line integral + + align:start position:0% +C1 of f dodr minus the line integral + + + align:start position:0% +C1 of f dodr minus the line integral +over + + align:start position:0% +over + + + align:start position:0% +over +C of f do Dr and so what's nice about + + align:start position:0% +C of f do Dr and so what's nice about + + + align:start position:0% +C of f do Dr and so what's nice about +this formula is that it replaces the + + align:start position:0% +this formula is that it replaces the + + + align:start position:0% +this formula is that it replaces the +thing that we Computing the thing that + + align:start position:0% +thing that we Computing the thing that + + + align:start position:0% +thing that we Computing the thing that +we want Computing the integral that we + + align:start position:0% +we want Computing the integral that we + + + align:start position:0% +we want Computing the integral that we +want instead of computing that we can + + align:start position:0% +want instead of computing that we can + + + align:start position:0% +want instead of computing that we can +try and compute this other line integral + + align:start position:0% +try and compute this other line integral + + + align:start position:0% +try and compute this other line integral +and the surface integral and if these + + align:start position:0% +and the surface integral and if these + + + align:start position:0% +and the surface integral and if these +are easier to compute well then the + + align:start position:0% +are easier to compute well then the + + + align:start position:0% +are easier to compute well then the +Computing the two of them gives us what + + align:start position:0% +Computing the two of them gives us what + + + align:start position:0% +Computing the two of them gives us what +the value of this is just by subtracting + + align:start position:0% +the value of this is just by subtracting + + + align:start position:0% +the value of this is just by subtracting +or adding and subtracting or whatever by + + align:start position:0% +or adding and subtracting or whatever by + + + align:start position:0% +or adding and subtracting or whatever by +arithmetic right so it so so if these + + align:start position:0% +arithmetic right so it so so if these + + + align:start position:0% +arithmetic right so it so so if these +integrals are easy to compute then that + + align:start position:0% +integrals are easy to compute then that + + + align:start position:0% +integrals are easy to compute then that +makes this one easy without actually + + align:start position:0% +makes this one easy without actually + + + align:start position:0% +makes this one easy without actually +having to parameterize and compute it so + + align:start position:0% +having to parameterize and compute it so + + + align:start position:0% +having to parameterize and compute it so +let's take a look at what these + + align:start position:0% +let's take a look at what these + + + align:start position:0% +let's take a look at what these +integrals are so we've got um let's + + align:start position:0% +integrals are so we've got um let's + + + align:start position:0% +integrals are so we've got um let's +let's do the surface integral first + + align:start position:0% +let's do the surface integral first + + + align:start position:0% +let's do the surface integral first +since it's on the left so in order to + + align:start position:0% +since it's on the left so in order to + + + align:start position:0% +since it's on the left so in order to +compute the surface integral we're going + + align:start position:0% +compute the surface integral we're going + + + align:start position:0% +compute the surface integral we're going +to need to compute the curl of f um so + + align:start position:0% +to need to compute the curl of f um so + + + align:start position:0% +to need to compute the curl of f um so +okay so f is this kind of messy looking + + align:start position:0% +okay so f is this kind of messy looking + + + align:start position:0% +okay so f is this kind of messy looking +thing here so curl of + + align:start position:0% + + + + align:start position:0% + +f well okay so what have we got so it's + + align:start position:0% +f well okay so what have we got so it's + + + align:start position:0% +f well okay so what have we got so it's +going to + + align:start position:0% +going to + + + align:start position:0% +going to +be big thing times I hat so it's going + + align:start position:0% +be big thing times I hat so it's going + + + align:start position:0% +be big thing times I hat so it's going +to be I hat times so you know it's this + + align:start position:0% +to be I hat times so you know it's this + + + align:start position:0% +to be I hat times so you know it's this +determinant right so let me let me write + + align:start position:0% +determinant right so let me let me write + + + align:start position:0% +determinant right so let me let me write +the determinant so we've got on top + + align:start position:0% +the determinant so we've got on top + + + align:start position:0% +the determinant so we've got on top +we've got I hat J hat K hat then we have + + align:start position:0% +we've got I hat J hat K hat then we have + + + align:start position:0% +we've got I hat J hat K hat then we have +the partial X partial y partial Z and + + align:start position:0% +the partial X partial y partial Z and + + + align:start position:0% +the partial X partial y partial Z and +then we have the components so these are + + align:start position:0% +then we have the components so these are + + + align:start position:0% +then we have the components so these are +2xz - 2 Y and 2 y z minus no + + + align:start position:0% +2xz - 2 Y and 2 y z minus no + + + + align:start position:0% +2xz - 2 Y and 2 y z minus no + +2x and x² + Y 2 + z s all right so + + align:start position:0% +2x and x² + Y 2 + z s all right so + + + align:start position:0% +2x and x² + Y 2 + z s all right so +that's I hat J hat K hat and we've + + align:start position:0% +that's I hat J hat K hat and we've + + + align:start position:0% +that's I hat J hat K hat and we've +got partial over partial X partial over + + align:start position:0% +got partial over partial X partial over + + + align:start position:0% +got partial over partial X partial over +partial Y and partial + + align:start position:0% +partial Y and partial + + + align:start position:0% +partial Y and partial +over partial Z so this is what the curl + + align:start position:0% +over partial Z so this is what the curl + + + align:start position:0% +over partial Z so this is what the curl +is and so now we have to expand this out + + align:start position:0% +is and so now we have to expand this out + + + align:start position:0% +is and so now we have to expand this out +so for I it's going to be partial y of + + align:start position:0% +so for I it's going to be partial y of + + + align:start position:0% +so for I it's going to be partial y of +X2 + y^2 + z^2 so that's 2 + + align:start position:0% +X2 + y^2 + z^2 so that's 2 + + + align:start position:0% +X2 + y^2 + z^2 so that's 2 +y minus partial Z of 2 YZ + 2x so that's + + align:start position:0% +y minus partial Z of 2 YZ + 2x so that's + + + align:start position:0% +y minus partial Z of 2 YZ + 2x so that's +minus 2 + + align:start position:0% +minus 2 + + + align:start position:0% +minus 2 +y i hat + + align:start position:0% +y i hat + + + align:start position:0% +y i hat +plus so for J hat it's going to be + + align:start position:0% +plus so for J hat it's going to be + + + align:start position:0% +plus so for J hat it's going to be +partial Z of + + align:start position:0% +partial Z of + + + align:start position:0% +partial Z of +2xz minus 2 y so that's + + align:start position:0% +2xz minus 2 y so that's + + + align:start position:0% +2xz minus 2 y so that's +2x minus partial X of x^2 + y^2 + z^2 so + + align:start position:0% +2x minus partial X of x^2 + y^2 + z^2 so + + + align:start position:0% +2x minus partial X of x^2 + y^2 + z^2 so +that's - + + align:start position:0% +that's - + + + align:start position:0% +that's - +2x J hat plus let's see for K hat we + + align:start position:0% +2x J hat plus let's see for K hat we + + + align:start position:0% +2x J hat plus let's see for K hat we +want partial X of 2 YZ + 2x so that's + + align:start position:0% +want partial X of 2 YZ + 2x so that's + + + align:start position:0% +want partial X of 2 YZ + 2x so that's +2 minus partial y of 2xz - 2 y y so + + align:start position:0% +2 minus partial y of 2xz - 2 y y so + + + align:start position:0% +2 minus partial y of 2xz - 2 y y so +that's Min - - 2 so that's + 2 K hat and + + align:start position:0% +that's Min - - 2 so that's + 2 K hat and + + + align:start position:0% +that's Min - - 2 so that's + 2 K hat and +oh all right so this okay so the I + + align:start position:0% +oh all right so this okay so the I + + + align:start position:0% +oh all right so this okay so the I +component is zero and the J component is + + align:start position:0% +component is zero and the J component is + + + align:start position:0% +component is zero and the J component is +zero so this is a nice simple one so the + + align:start position:0% +zero so this is a nice simple one so the + + + align:start position:0% +zero so this is a nice simple one so the +curl here the K component is just four + + align:start position:0% +curl here the K component is just four + + + align:start position:0% +curl here the K component is just four +so this is equal to + + align:start position:0% +so this is equal to + + + align:start position:0% +so this is equal to + + align:start position:0% + + + align:start position:0% +K okay so that's what the curl of f is + + align:start position:0% +K okay so that's what the curl of f is + + + align:start position:0% +K okay so that's what the curl of f is +now what do we need to compute we need + + align:start position:0% +now what do we need to compute we need + + + align:start position:0% +now what do we need to compute we need +to compute curl of f do the normal + + align:start position:0% +to compute curl of f do the normal + + + align:start position:0% +to compute curl of f do the normal +Vector with with respect to surface area + + align:start position:0% +Vector with with respect to surface area + + + align:start position:0% +Vector with with respect to surface area +now let's look at what our surface is + + align:start position:0% +now let's look at what our surface is + + + align:start position:0% +now let's look at what our surface is +our surface is right here and it's this + + align:start position:0% +our surface is right here and it's this + + + align:start position:0% +our surface is right here and it's this +cylinder it's this vertical cylinder + + align:start position:0% +cylinder it's this vertical cylinder + + + align:start position:0% +cylinder it's this vertical cylinder +well what is the normal Vector of a + + align:start position:0% +well what is the normal Vector of a + + + align:start position:0% +well what is the normal Vector of a +vertical cylinder well it's it's + + align:start position:0% +vertical cylinder well it's it's + + + align:start position:0% +vertical cylinder well it's it's +pointing straight away from the axis + + align:start position:0% +pointing straight away from the axis + + + align:start position:0% +pointing straight away from the axis +right it's it's perpendicular to the + + align:start position:0% +right it's it's perpendicular to the + + + align:start position:0% +right it's it's perpendicular to the +surface of the cylinder so it's parallel + + align:start position:0% +surface of the cylinder so it's parallel + + + align:start position:0% +surface of the cylinder so it's parallel +to the XY + + align:start position:0% +to the XY + + + align:start position:0% +to the XY +plane you know in whichever it rotates + + align:start position:0% +plane you know in whichever it rotates + + + align:start position:0% +plane you know in whichever it rotates +as you as you go around the cylinder but + + align:start position:0% +as you as you go around the cylinder but + + + align:start position:0% +as you as you go around the cylinder but +it's always in the XY plane so what is + + align:start position:0% +it's always in the XY plane so what is + + + align:start position:0% +it's always in the XY plane so what is +that mean well that means in particular + + align:start position:0% +that mean well that means in particular + + + align:start position:0% +that mean well that means in particular +it's perpendicular to to things in the Z + + align:start position:0% +it's perpendicular to to things in the Z + + + align:start position:0% +it's perpendicular to to things in the Z +direction right so if we look we see our + + align:start position:0% +direction right so if we look we see our + + + align:start position:0% +direction right so if we look we see our +curl here is just straight upward in the + + align:start position:0% +curl here is just straight upward in the + + + align:start position:0% +curl here is just straight upward in the +Z Direction and our normal Vector is has + + align:start position:0% +Z Direction and our normal Vector is has + + + align:start position:0% +Z Direction and our normal Vector is has +no Z component it's only in the in the + + align:start position:0% +no Z component it's only in the in the + + + align:start position:0% +no Z component it's only in the in the +XY plane so this this K hat is is + + align:start position:0% +XY plane so this this K hat is is + + + align:start position:0% +XY plane so this this K hat is is +orthogonal to n okay so the curl and N + + align:start position:0% +orthogonal to n okay so the curl and N + + + align:start position:0% +orthogonal to n okay so the curl and N +are orthogonal so their dot product is + + align:start position:0% +are orthogonal so their dot product is + + + align:start position:0% +are orthogonal so their dot product is +zero so this C surf integral is a + + align:start position:0% +zero so this C surf integral is a + + + align:start position:0% +zero so this C surf integral is a +Surface integral of zero so it just + + align:start position:0% +Surface integral of zero so it just + + + align:start position:0% +Surface integral of zero so it just +gives you zero okay so great so that's + + align:start position:0% +gives you zero okay so great so that's + + + align:start position:0% +gives you zero okay so great so that's +really nice that simplifies our life + + align:start position:0% +really nice that simplifies our life + + + align:start position:0% +really nice that simplifies our life +very much now our our line integral that + + align:start position:0% +very much now our our line integral that + + + align:start position:0% +very much now our our line integral that +we want we just have it in terms of just + + align:start position:0% +we want we just have it in terms of just + + + align:start position:0% +we want we just have it in terms of just +this one other line integral right so + + align:start position:0% +this one other line integral right so + + + align:start position:0% +this one other line integral right so +the surface integral is + + align:start position:0% +the surface integral is + + + align:start position:0% +the surface integral is +zero let me see where should I put this + + align:start position:0% +zero let me see where should I put this + + + align:start position:0% +zero let me see where should I put this +okay the curl is 4K + + align:start position:0% +okay the curl is 4K + + + align:start position:0% +okay the curl is 4K +so the surface + + align:start position:0% +so the surface + + + align:start position:0% +so the surface +integral curl f + + align:start position:0% +integral curl f + + + align:start position:0% +integral curl f +n DS is also equal to + + align:start position:0% +n DS is also equal to + + + align:start position:0% +n DS is also equal to +zero so having made that simplification + + align:start position:0% +zero so having made that simplification + + + align:start position:0% +zero so having made that simplification +now we just need now we just need this + + align:start position:0% +now we just need now we just need this + + + align:start position:0% +now we just need now we just need this +other uh integral we need this line + + align:start position:0% +other uh integral we need this line + + + align:start position:0% +other uh integral we need this line +integral over + + align:start position:0% +integral over + + + align:start position:0% +integral over +C1 and that'll give us what what we need + + align:start position:0% +C1 and that'll give us what what we need + + + align:start position:0% +C1 and that'll give us what what we need +so let's so let's have a go at that so + + align:start position:0% +so let's so let's have a go at that so + + + align:start position:0% +so let's so let's have a go at that so +C1 so C1 is the + + align:start position:0% + + + + align:start position:0% + +circle of + + align:start position:0% +circle of + + + align:start position:0% +circle of +radius B centered at the origin in the + + align:start position:0% +radius B centered at the origin in the + + + align:start position:0% +radius B centered at the origin in the +XY plane okay I'm not going to write + + align:start position:0% +XY plane okay I'm not going to write + + + align:start position:0% +XY plane okay I'm not going to write +that down I'm just going to say it's the + + align:start position:0% +that down I'm just going to say it's the + + + align:start position:0% +that down I'm just going to say it's the +circle of radius B centered at the + + align:start position:0% +circle of radius B centered at the + + + align:start position:0% +circle of radius B centered at the +origin in the XY plane so okay so it's + + align:start position:0% +origin in the XY plane so okay so it's + + + align:start position:0% +origin in the XY plane so okay so it's +not that hard to parameterize so we have + + align:start position:0% +not that hard to parameterize so we have + + + align:start position:0% +not that hard to parameterize so we have +that um so it's parameterized by xals B + + align:start position:0% +that um so it's parameterized by xals B + + + align:start position:0% +that um so it's parameterized by xals B +cosine Theta y + + align:start position:0% +cosine Theta y + + + align:start position:0% +cosine Theta y += b sin Theta we should check we should + + align:start position:0% += b sin Theta we should check we should + + + align:start position:0% += b sin Theta we should check we should +double check that we're doing the right + + align:start position:0% +double check that we're doing the right + + + align:start position:0% +double check that we're doing the right +the right direction of parameterization + + align:start position:0% +the right direction of parameterization + + + align:start position:0% +the right direction of parameterization +let's go have a look let's + + align:start position:0% +let's go have a look let's + + + align:start position:0% +let's go have a look let's +see yes okay so we parameterized this + + align:start position:0% +see yes okay so we parameterized this + + + align:start position:0% +see yes okay so we parameterized this +circle going counterclockwise in the XY + + align:start position:0% +circle going counterclockwise in the XY + + + align:start position:0% +circle going counterclockwise in the XY +plane so good so this parameterization + + align:start position:0% +plane so good so this parameterization + + + align:start position:0% +plane so good so this parameterization +is going the right direction otherwise + + align:start position:0% +is going the right direction otherwise + + + align:start position:0% +is going the right direction otherwise +we'd have to you know change the sign of + + align:start position:0% +we'd have to you know change the sign of + + + align:start position:0% +we'd have to you know change the sign of +theta or something um so it's X is B + + align:start position:0% +theta or something um so it's X is B + + + align:start position:0% +theta or something um so it's X is B +cosine Theta Y is B sin Theta and we're + + align:start position:0% +cosine Theta Y is B sin Theta and we're + + + align:start position:0% +cosine Theta Y is B sin Theta and we're +going once around the circle so we want + + align:start position:0% +going once around the circle so we want + + + align:start position:0% +going once around the circle so we want +0 less than or equal to Theta less than + + align:start position:0% +0 less than or equal to Theta less than + + + align:start position:0% +0 less than or equal to Theta less than +or equal to 2 pi and so what do we have + + align:start position:0% +or equal to 2 pi and so what do we have + + + align:start position:0% +or equal to 2 pi and so what do we have +so now we want to look at we want to + + align:start position:0% +so now we want to look at we want to + + + align:start position:0% +so now we want to look at we want to +compute the integral over this circle + + align:start position:0% +compute the integral over this circle + + + align:start position:0% +compute the integral over this circle +of + + align:start position:0% +of + + + align:start position:0% +of +f + + align:start position:0% +f + + + align:start position:0% +f +do + + align:start position:0% +do + + + align:start position:0% +do +Dr so let's see what F looks like in + + align:start position:0% +Dr so let's see what F looks like in + + + align:start position:0% +Dr so let's see what F looks like in +this in this situation so let's go back + + align:start position:0% +this in this situation so let's go back + + + align:start position:0% +this in this situation so let's go back +and look at the expression for f over + + align:start position:0% +and look at the expression for f over + + + align:start position:0% +and look at the expression for f over +here + + align:start position:0% +here + + + align:start position:0% +here +um so in this plane we have Z is equal + + align:start position:0% +um so in this plane we have Z is equal + + + align:start position:0% +um so in this plane we have Z is equal +to zero so f is minus 2 y + 2x x^2 + y^ + + align:start position:0% +to zero so f is minus 2 y + 2x x^2 + y^ + + + align:start position:0% +to zero so f is minus 2 y + 2x x^2 + y^ +2 okay so okay so let's come back then + + align:start position:0% +2 okay so okay so let's come back then + + + align:start position:0% +2 okay so okay so let's come back then +so f is that what I just said so this is + + align:start position:0% +so f is that what I just said so this is + + + align:start position:0% +so f is that what I just said so this is +equal to the integral of over C of - 2 + + align:start position:0% +equal to the integral of over C of - 2 + + + align:start position:0% +equal to the integral of over C of - 2 +y + + align:start position:0% +y + + + align:start position:0% +y +DX + + + align:start position:0% +DX + + + + align:start position:0% +DX + +2x + + align:start position:0% +2x + + + align:start position:0% +2x +Dy plus okay X2 + y^2 DZ but we're in + + align:start position:0% +Dy plus okay X2 + y^2 DZ but we're in + + + align:start position:0% +Dy plus okay X2 + y^2 DZ but we're in +the plane Z equals z so DZ is always + + align:start position:0% +the plane Z equals z so DZ is always + + + align:start position:0% +the plane Z equals z so DZ is always +zero in that plane so we don't have a + + align:start position:0% +zero in that plane so we don't have a + + + align:start position:0% +zero in that plane so we don't have a +third term there great um so this is our + + align:start position:0% +third term there great um so this is our + + + align:start position:0% +third term there great um so this is our +our integral and now we can substitute + + align:start position:0% +our integral and now we can substitute + + + align:start position:0% +our integral and now we can substitute +from our parameterization here so this + + align:start position:0% +from our parameterization here so this + + + align:start position:0% +from our parameterization here so this +is equal to the integral from 0 to 2 pi + + align:start position:0% +is equal to the integral from 0 to 2 pi + + + align:start position:0% +is equal to the integral from 0 to 2 pi +let's see so 2 - 2 y DX so that's - 2b + + align:start position:0% +let's see so 2 - 2 y DX so that's - 2b + + + align:start position:0% +let's see so 2 - 2 y DX so that's - 2b +sin + + align:start position:0% + + + + align:start position:0% + +Theta times DX is minus + + align:start position:0% +Theta times DX is minus + + + align:start position:0% +Theta times DX is minus +B + + align:start position:0% + + + + align:start position:0% + +sin + + align:start position:0% +sin + + + align:start position:0% +sin +Theta D + + align:start position:0% +Theta D + + + align:start position:0% +Theta D +theta plus 2X so that's 2 B cosine + + align:start position:0% + + + + align:start position:0% + +Theta time Dy which is B cosine Theta D + + align:start position:0% +Theta time Dy which is B cosine Theta D + + + align:start position:0% +Theta time Dy which is B cosine Theta D +Theta time B cosine Theta D Theta this + + align:start position:0% +Theta time B cosine Theta D Theta this + + + align:start position:0% +Theta time B cosine Theta D Theta this +is quite a long equation isn't it all + + align:start position:0% +is quite a long equation isn't it all + + + align:start position:0% +is quite a long equation isn't it all +right so or long expression I guess so + + align:start position:0% +right so or long expression I guess so + + + align:start position:0% +right so or long expression I guess so +we've got the so our our line integral + + align:start position:0% +we've got the so our our line integral + + + align:start position:0% +we've got the so our our line integral +on C around C of f dodr is equal to the + + align:start position:0% +on C around C of f dodr is equal to the + + + align:start position:0% +on C around C of f dodr is equal to the +integral from 0 to 2 pi of minus 2 B sin + + align:start position:0% +integral from 0 to 2 pi of minus 2 B sin + + + align:start position:0% +integral from 0 to 2 pi of minus 2 B sin +Theta * minus B sin Theta D Theta so + + align:start position:0% +Theta * minus B sin Theta D Theta so + + + align:start position:0% +Theta * minus B sin Theta D Theta so +this is 2 b^ 2 sin^2 Theta D Theta and + + align:start position:0% +this is 2 b^ 2 sin^2 Theta D Theta and + + + align:start position:0% +this is 2 b^ 2 sin^2 Theta D Theta and +this is 2 b^2 cosine 2 Theta D Theta so + + align:start position:0% +this is 2 b^2 cosine 2 Theta D Theta so + + + align:start position:0% +this is 2 b^2 cosine 2 Theta D Theta so +okay so we can that 2 b^2 that's a + + align:start position:0% +okay so we can that 2 b^2 that's a + + + align:start position:0% +okay so we can that 2 b^2 that's a +constant we can just Factor it out and + + align:start position:0% +constant we can just Factor it out and + + + align:start position:0% +constant we can just Factor it out and +we're left with sin squ theta plus + + align:start position:0% +we're left with sin squ theta plus + + + align:start position:0% +we're left with sin squ theta plus +cosine s Theta D Theta all right but + + align:start position:0% +cosine s Theta D Theta all right but + + + align:start position:0% +cosine s Theta D Theta all right but +that's okay that's you know that's great + + align:start position:0% +that's okay that's you know that's great + + + align:start position:0% +that's okay that's you know that's great +that I'm ha happy to have that right sin + + align:start position:0% +that I'm ha happy to have that right sin + + + align:start position:0% +that I'm ha happy to have that right sin +Square theta plus cosine Square Theta + + align:start position:0% +Square theta plus cosine Square Theta + + + align:start position:0% +Square theta plus cosine Square Theta +that's going to be one okay so let's so + + align:start position:0% +that's going to be one okay so let's so + + + align:start position:0% +that's going to be one okay so let's so +we can rewrite this I'm going to bring + + align:start position:0% +we can rewrite this I'm going to bring + + + align:start position:0% +we can rewrite this I'm going to bring +it back up here so that's equal to the + + align:start position:0% +it back up here so that's equal to the + + + align:start position:0% +it back up here so that's equal to the +integral from 0 to 2 pi of 2 + + align:start position:0% +integral from 0 to 2 pi of 2 + + + align:start position:0% +integral from 0 to 2 pi of 2 +b^2 D Theta which is 4 pi b + + align:start position:0% +b^2 D Theta which is 4 pi b + + + align:start position:0% +b^2 D Theta which is 4 pi b +^2 great okay so that's our line + + align:start position:0% +^2 great okay so that's our line + + + align:start position:0% +^2 great okay so that's our line +integral around this bottom curve + + align:start position:0% +integral around this bottom curve + + + align:start position:0% +integral around this bottom curve +C oh dear I've been I've been writing C + + align:start position:0% +C oh dear I've been I've been writing C + + + align:start position:0% +C oh dear I've been I've been writing C +but this is our not our original curve C + + align:start position:0% +but this is our not our original curve C + + + align:start position:0% +but this is our not our original curve C +this is our new curve C1 like I wrote + + align:start position:0% +this is our new curve C1 like I wrote + + + align:start position:0% +this is our new curve C1 like I wrote +there sorry so everywhere I wrote the + + align:start position:0% +there sorry so everywhere I wrote the + + + align:start position:0% +there sorry so everywhere I wrote the +line integral over C both of these + + align:start position:0% +line integral over C both of these + + + align:start position:0% +line integral over C both of these +places it was supposed to be a line + + align:start position:0% +places it was supposed to be a line + + + align:start position:0% +places it was supposed to be a line +integral over C1 sorry about that so + + align:start position:0% +integral over C1 sorry about that so + + + align:start position:0% +integral over C1 sorry about that so +we've got this line integral over C1 and + + align:start position:0% +we've got this line integral over C1 and + + + align:start position:0% +we've got this line integral over C1 and +it worked out to 4 pi b ^2 just using + + align:start position:0% +it worked out to 4 pi b ^2 just using + + + align:start position:0% +it worked out to 4 pi b ^2 just using +our usual parameterize and and compute + + align:start position:0% +our usual parameterize and and compute + + + align:start position:0% +our usual parameterize and and compute +um technique for computing line + + align:start position:0% +um technique for computing line + + + align:start position:0% +um technique for computing line +integrals so okay so now let's see where + + align:start position:0% +integrals so okay so now let's see where + + + align:start position:0% +integrals so okay so now let's see where +we're at let's go back uh over here to + + align:start position:0% +we're at let's go back uh over here to + + + align:start position:0% +we're at let's go back uh over here to +to when we wrote down what the extended + + align:start position:0% +to when we wrote down what the extended + + + align:start position:0% +to when we wrote down what the extended +Stokes theorem says in our case so + + align:start position:0% +Stokes theorem says in our case so + + + align:start position:0% +Stokes theorem says in our case so +Stokes theor told us that the thing we + + align:start position:0% +Stokes theor told us that the thing we + + + align:start position:0% +Stokes theor told us that the thing we +were interested this is the the thing + + align:start position:0% +were interested this is the the thing + + + align:start position:0% +were interested this is the the thing +we're trying to compute right the + + align:start position:0% +we're trying to compute right the + + + align:start position:0% +we're trying to compute right the +problem asked us to compute the integral + + align:start position:0% +problem asked us to compute the integral + + + align:start position:0% +problem asked us to compute the integral +of the line integral over C of f. + + align:start position:0% +of the line integral over C of f. + + + align:start position:0% +of the line integral over C of f. +drr well extended Stokes theorem said in + + align:start position:0% +drr well extended Stokes theorem said in + + + align:start position:0% +drr well extended Stokes theorem said in +order to compute this this line integral + + align:start position:0% +order to compute this this line integral + + + align:start position:0% +order to compute this this line integral +what you can do is you can compute this + + align:start position:0% +what you can do is you can compute this + + + align:start position:0% +what you can do is you can compute this +surface integral over s and you can + + align:start position:0% +surface integral over s and you can + + + align:start position:0% +surface integral over s and you can +compute this line integral over this + + align:start position:0% +compute this line integral over this + + + align:start position:0% +compute this line integral over this +other curve C1 and then these three + + align:start position:0% +other curve C1 and then these three + + + align:start position:0% +other curve C1 and then these three +things have to satisfy this relationship + + align:start position:0% +things have to satisfy this relationship + + + align:start position:0% +things have to satisfy this relationship +that's what Stokes theorem says and now + + align:start position:0% +that's what Stokes theorem says and now + + + align:start position:0% +that's what Stokes theorem says and now +we've computed we've computed the + + align:start position:0% +we've computed we've computed the + + + align:start position:0% +we've computed we've computed the +service integral we found it was equal + + align:start position:0% +service integral we found it was equal + + + align:start position:0% +service integral we found it was equal +to zero by a simple geometric argument + + align:start position:0% +to zero by a simple geometric argument + + + align:start position:0% +to zero by a simple geometric argument +that didn't require us to actually + + align:start position:0% +that didn't require us to actually + + + align:start position:0% +that didn't require us to actually +compute a surface integral um and we + + align:start position:0% +compute a surface integral um and we + + + align:start position:0% +compute a surface integral um and we +computed this line integral just now uh + + align:start position:0% +computed this line integral just now uh + + + align:start position:0% +computed this line integral just now uh +by by parameterizing and comput again so + + align:start position:0% +by by parameterizing and comput again so + + + align:start position:0% +by by parameterizing and comput again so +okay so this was zero and this was 4 Pi + + align:start position:0% +okay so this was zero and this was 4 Pi + + + align:start position:0% +okay so this was zero and this was 4 Pi +b^2 so if we just add our integral in + + align:start position:0% +b^2 so if we just add our integral in + + + align:start position:0% +b^2 so if we just add our integral in +question to the other side what we find + + align:start position:0% +question to the other side what we find + + + align:start position:0% +question to the other side what we find +I'm going to go find some empty board + + align:start position:0% +I'm going to go find some empty board + + + align:start position:0% +I'm going to go find some empty board +space to write it down so our + + align:start position:0% + + + + align:start position:0% + +integral so our integral the integral + + align:start position:0% +integral so our integral the integral + + + align:start position:0% +integral so our integral the integral +over + + align:start position:0% +over + + + align:start position:0% +over +C of f dot Dr well it's equal to the + + align:start position:0% +C of f dot Dr well it's equal to the + + + align:start position:0% +C of f dot Dr well it's equal to the +surface integral sorry it's equal to the + + align:start position:0% +surface integral sorry it's equal to the + + + align:start position:0% +surface integral sorry it's equal to the +to our to this other line integral minus + + align:start position:0% +to our to this other line integral minus + + + align:start position:0% +to our to this other line integral minus +the surface integral so it's equal to 4 + + align:start position:0% +the surface integral so it's equal to 4 + + + align:start position:0% +the surface integral so it's equal to 4 +piun B ^2 - 0 just rearranging that + + align:start position:0% +piun B ^2 - 0 just rearranging that + + + align:start position:0% +piun B ^2 - 0 just rearranging that +equation we were looking at a second ago + + align:start position:0% +equation we were looking at a second ago + + + align:start position:0% +equation we were looking at a second ago +from Stokes theorem so it's just 4 pi b + + align:start position:0% +from Stokes theorem so it's just 4 pi b + + + align:start position:0% +from Stokes theorem so it's just 4 pi b +^2 so that's the answer and I'll end + + align:start position:0% +^2 so that's the answer and I'll end + + + align:start position:0% +^2 so that's the answer and I'll end +there \ No newline at end of file diff --git a/8-HU6SwL9jo.txt b/8-HU6SwL9jo.txt new file mode 100644 index 0000000000000000000000000000000000000000..38d952566e7605377a2c39748dbeaa2c3ce94c5d --- /dev/null +++ b/8-HU6SwL9jo.txt @@ -0,0 +1,1203 @@ +align:start position:0% + +all right so welcome back to 8701 + + align:start position:0% +all right so welcome back to 8701 + + + align:start position:0% +all right so welcome back to 8701 +so we have all ingredients now to + + align:start position:0% +so we have all ingredients now to + + + align:start position:0% +so we have all ingredients now to +prepare + + align:start position:0% +prepare + + + align:start position:0% +prepare +fireman rules for qed so that's the + + align:start position:0% +fireman rules for qed so that's the + + + align:start position:0% +fireman rules for qed so that's the +toolkit we need in order to make + + align:start position:0% +toolkit we need in order to make + + + align:start position:0% +toolkit we need in order to make +calculations to calculate scattering + + align:start position:0% +calculations to calculate scattering + + + align:start position:0% +calculations to calculate scattering +processes + + align:start position:0% +processes + + + align:start position:0% +processes +in the case and we have already seen + + align:start position:0% +in the case and we have already seen + + + align:start position:0% +in the case and we have already seen +fileman rules for our toy theory + + align:start position:0% +fileman rules for our toy theory + + + align:start position:0% +fileman rules for our toy theory +again now the situation is a little bit + + align:start position:0% +again now the situation is a little bit + + + align:start position:0% +again now the situation is a little bit +more complicated because we can consider + + align:start position:0% +more complicated because we can consider + + + align:start position:0% +more complicated because we can consider +the spin of particles in addition + + align:start position:0% +the spin of particles in addition + + + align:start position:0% +the spin of particles in addition +to their energy and momenta the rules + + align:start position:0% +to their energy and momenta the rules + + + align:start position:0% +to their energy and momenta the rules +sequence of things are very much the + + align:start position:0% +sequence of things are very much the + + + align:start position:0% +sequence of things are very much the +same there is however a few caveats to + + align:start position:0% +same there is however a few caveats to + + + align:start position:0% +same there is however a few caveats to +keep in mind and i'll point out + + align:start position:0% +keep in mind and i'll point out + + + align:start position:0% +keep in mind and i'll point out +okay so the very first thing is to be + + align:start position:0% +okay so the very first thing is to be + + + align:start position:0% +okay so the very first thing is to be +very clear in + + align:start position:0% +very clear in + + + align:start position:0% +very clear in +our notation so this is an arbitrary + + align:start position:0% +our notation so this is an arbitrary + + + align:start position:0% +our notation so this is an arbitrary +or generic qed farming diagram we have + + align:start position:0% +or generic qed farming diagram we have + + + align:start position:0% +or generic qed farming diagram we have +only + + align:start position:0% +only + + + align:start position:0% +only +pointed out the incoming and the + + align:start position:0% +pointed out the incoming and the + + + align:start position:0% +pointed out the incoming and the +outgoing + + align:start position:0% +outgoing + + + align:start position:0% +outgoing +so there's internal lines which i didn't + + align:start position:0% +so there's internal lines which i didn't + + + align:start position:0% +so there's internal lines which i didn't +mention here + + align:start position:0% +mention here + + + align:start position:0% +mention here +important to note the momentum momentum + + align:start position:0% +important to note the momentum momentum + + + align:start position:0% +important to note the momentum momentum +and the directions the directions are + + align:start position:0% +and the directions the directions are + + + align:start position:0% +and the directions the directions are +arbitrary we just have to be clear on + + align:start position:0% +arbitrary we just have to be clear on + + + align:start position:0% +arbitrary we just have to be clear on +them and then + + align:start position:0% +them and then + + + align:start position:0% +them and then +treat them consistently right so this is + + align:start position:0% +treat them consistently right so this is + + + align:start position:0% +treat them consistently right so this is +not different in our previous discussion + + align:start position:0% +not different in our previous discussion + + + align:start position:0% +not different in our previous discussion +then here comes the difference um + + align:start position:0% +then here comes the difference um + + + align:start position:0% +then here comes the difference um +our external lines are either electron + + align:start position:0% +our external lines are either electron + + + align:start position:0% +our external lines are either electron +positrons or photons + + align:start position:0% +positrons or photons + + + align:start position:0% +positrons or photons +right you can fermions and photons + + align:start position:0% +right you can fermions and photons + + + align:start position:0% +right you can fermions and photons +charged fermions and photons so we + + align:start position:0% +charged fermions and photons so we + + + align:start position:0% +charged fermions and photons so we +discussed how the solutions look like + + align:start position:0% +discussed how the solutions look like + + + align:start position:0% +discussed how the solutions look like +our spinos u + + align:start position:0% +our spinos u + + + align:start position:0% +our spinos u +and v and for outgoing for outgoing + + align:start position:0% +and v and for outgoing for outgoing + + + align:start position:0% +and v and for outgoing for outgoing +electrons for outgoing particles we have + + align:start position:0% +electrons for outgoing particles we have + + + align:start position:0% +electrons for outgoing particles we have +this adjunct vector here which is given + + align:start position:0% +this adjunct vector here which is given + + + align:start position:0% +this adjunct vector here which is given +by + + align:start position:0% +by + + + align:start position:0% +by +u dagger gamma zero and similarly for + + align:start position:0% +u dagger gamma zero and similarly for + + + align:start position:0% +u dagger gamma zero and similarly for +the incoming anti-particle + + align:start position:0% +the incoming anti-particle + + + align:start position:0% +the incoming anti-particle +v dagger gamma zero for the photon we + + align:start position:0% +v dagger gamma zero for the photon we + + + align:start position:0% +v dagger gamma zero for the photon we +have the polarization vectors + + align:start position:0% +have the polarization vectors + + + align:start position:0% +have the polarization vectors +for incoming and outgoing photons + + align:start position:0% + + + + align:start position:0% + +all right then we have a vertex vector + + align:start position:0% +all right then we have a vertex vector + + + align:start position:0% +all right then we have a vertex vector +here now g + + align:start position:0% +here now g + + + align:start position:0% +here now g +zero or ge is a + + align:start position:0% +zero or ge is a + + + align:start position:0% +zero or ge is a +constant um and a dimensionless property + + align:start position:0% +constant um and a dimensionless property + + + align:start position:0% +constant um and a dimensionless property +but we do have to have a gamma gamma mu + + align:start position:0% +but we do have to have a gamma gamma mu + + + align:start position:0% +but we do have to have a gamma gamma mu +here + + align:start position:0% +here + + + align:start position:0% +here +um as part of our vertex factor + + align:start position:0% +um as part of our vertex factor + + + align:start position:0% +um as part of our vertex factor +for the propagator or internal lines we + + align:start position:0% +for the propagator or internal lines we + + + align:start position:0% +for the propagator or internal lines we +have a difference between electrons + + align:start position:0% +have a difference between electrons + + + align:start position:0% +have a difference between electrons +positrons and photons and that comes + + align:start position:0% +positrons and photons and that comes + + + align:start position:0% +positrons and photons and that comes +from the fact + + align:start position:0% +from the fact + + + align:start position:0% +from the fact +that electrons impose it from the mass + + align:start position:0% +that electrons impose it from the mass + + + align:start position:0% +that electrons impose it from the mass +of particles + + align:start position:0% +of particles + + + align:start position:0% +of particles +so we have vertex vectors which + + align:start position:0% + + + + align:start position:0% + +know have you know this one over q + + align:start position:0% +know have you know this one over q + + + align:start position:0% +know have you know this one over q +square behavior or one over excuse me + + align:start position:0% +square behavior or one over excuse me + + + align:start position:0% +square behavior or one over excuse me +minus m square behavior + + align:start position:0% +minus m square behavior + + + align:start position:0% +minus m square behavior +so here you can already see that there's + + align:start position:0% +so here you can already see that there's + + + align:start position:0% +so here you can already see that there's +going to be a complication later when we + + align:start position:0% +going to be a complication later when we + + + align:start position:0% +going to be a complication later when we +evaluate + + align:start position:0% +evaluate + + + align:start position:0% +evaluate +or integrate our momentum simply uh the + + align:start position:0% +or integrate our momentum simply uh the + + + align:start position:0% +or integrate our momentum simply uh the +same discussion had before and we + + align:start position:0% +same discussion had before and we + + + align:start position:0% +same discussion had before and we +already know how to solve this problem + + align:start position:0% +already know how to solve this problem + + + align:start position:0% +already know how to solve this problem +uh of infinities by renormalizing by + + align:start position:0% +uh of infinities by renormalizing by + + + align:start position:0% +uh of infinities by renormalizing by +having a cut off and we + + align:start position:0% +having a cut off and we + + + align:start position:0% +having a cut off and we +normalizing them excellent + + align:start position:0% +normalizing them excellent + + + align:start position:0% +normalizing them excellent +so the next steps end is very much the + + align:start position:0% +so the next steps end is very much the + + + align:start position:0% +so the next steps end is very much the +same uh there's no change + + align:start position:0% +same uh there's no change + + + align:start position:0% +same uh there's no change +we have to make sure that there's energy + + align:start position:0% +we have to make sure that there's energy + + + align:start position:0% +we have to make sure that there's energy +and momentum conservation and reinforces + + align:start position:0% +and momentum conservation and reinforces + + + align:start position:0% +and momentum conservation and reinforces +introducing delta functions uh we have + + align:start position:0% +introducing delta functions uh we have + + + align:start position:0% +introducing delta functions uh we have +to integrate over each and every + + align:start position:0% +to integrate over each and every + + + align:start position:0% +to integrate over each and every +internal momenta and each + + align:start position:0% +internal momenta and each + + + align:start position:0% +internal momenta and each +in each internal line + + align:start position:0% +in each internal line + + + align:start position:0% +in each internal line +gets one of those integration factors + + align:start position:0% +gets one of those integration factors + + + align:start position:0% +gets one of those integration factors +and then after we integrate we have to + + align:start position:0% +and then after we integrate we have to + + + align:start position:0% +and then after we integrate we have to +we are left with the delta function and + + align:start position:0% +we are left with the delta function and + + + align:start position:0% +we are left with the delta function and +we have to cancel that delta function + + align:start position:0% +we have to cancel that delta function + + + align:start position:0% +we have to cancel that delta function +all right in our toy experiment the + + align:start position:0% +all right in our toy experiment the + + + align:start position:0% +all right in our toy experiment the +order of things didn't matter + + align:start position:0% +order of things didn't matter + + + align:start position:0% +order of things didn't matter +everything we had in there was scala's + + align:start position:0% +everything we had in there was scala's + + + align:start position:0% +everything we had in there was scala's +numbers + + align:start position:0% +numbers + + + align:start position:0% +numbers +right here we do have a little bit more + + align:start position:0% +right here we do have a little bit more + + + align:start position:0% +right here we do have a little bit more +complicated problems so + + align:start position:0% +complicated problems so + + + align:start position:0% +complicated problems so +there's an importance in the order of + + align:start position:0% +there's an importance in the order of + + + align:start position:0% +there's an importance in the order of +which we execute things + + align:start position:0% +which we execute things + + + align:start position:0% +which we execute things +so what we're going to do is you know + + align:start position:0% +so what we're going to do is you know + + + align:start position:0% +so what we're going to do is you know +form firmware learn lines you just + + align:start position:0% +form firmware learn lines you just + + + align:start position:0% +form firmware learn lines you just +follow a fermion as we go from the left + + align:start position:0% +follow a fermion as we go from the left + + + align:start position:0% +follow a fermion as we go from the left +to the right + + align:start position:0% +to the right + + + align:start position:0% +to the right +and you will find things which are + + align:start position:0% +and you will find things which are + + + align:start position:0% +and you will find things which are +always of the form + + align:start position:0% +always of the form + + + align:start position:0% +always of the form +an adjoint spinner a four cross four + + align:start position:0% +an adjoint spinner a four cross four + + + align:start position:0% +an adjoint spinner a four cross four +times four matrix + + align:start position:0% +times four matrix + + + align:start position:0% +times four matrix +and a spino and the result of this is + + align:start position:0% +and a spino and the result of this is + + + align:start position:0% +and a spino and the result of this is +going to be a number + + align:start position:0% +going to be a number + + + align:start position:0% +going to be a number +all right great there is one additional + + align:start position:0% +all right great there is one additional + + + align:start position:0% +all right great there is one additional +complication + + align:start position:0% +complication + + + align:start position:0% +complication +is accounting for duplications and + + align:start position:0% +is accounting for duplications and + + + align:start position:0% +is accounting for duplications and +making sure that the sign is + + align:start position:0% +making sure that the sign is + + + align:start position:0% +making sure that the sign is +and i'm just mentioning this here this + + align:start position:0% +and i'm just mentioning this here this + + + align:start position:0% +and i'm just mentioning this here this +will become more clear + + align:start position:0% +will become more clear + + + align:start position:0% +will become more clear +as we walk through examples so there's + + align:start position:0% +as we walk through examples so there's + + + align:start position:0% +as we walk through examples so there's +an anti-semitration going on + + align:start position:0% +an anti-semitration going on + + + align:start position:0% +an anti-semitration going on +where we have to introduce a minus sign + + align:start position:0% +where we have to introduce a minus sign + + + align:start position:0% +where we have to introduce a minus sign +between the diagrams + + align:start position:0% +between the diagrams + + + align:start position:0% +between the diagrams +between different diagrams that differ + + align:start position:0% +between different diagrams that differ + + + align:start position:0% +between different diagrams that differ +only by the interchange or the exchange + + align:start position:0% +only by the interchange or the exchange + + + align:start position:0% +only by the interchange or the exchange +of two incoming + + align:start position:0% +of two incoming + + + align:start position:0% +of two incoming +or two outgoing electrons or positrons + + align:start position:0% +or two outgoing electrons or positrons + + + align:start position:0% +or two outgoing electrons or positrons +and or the incoming electron with an + + align:start position:0% +and or the incoming electron with an + + + align:start position:0% +and or the incoming electron with an +outgoing positron + + align:start position:0% +outgoing positron + + + align:start position:0% +outgoing positron +so you have a diagram which is exactly + + align:start position:0% +so you have a diagram which is exactly + + + align:start position:0% +so you have a diagram which is exactly +the same + + align:start position:0% +the same + + + align:start position:0% +the same +but you know the two incoming electrons + + align:start position:0% +but you know the two incoming electrons + + + align:start position:0% +but you know the two incoming electrons +are interchanged you have to add those + + align:start position:0% +are interchanged you have to add those + + + align:start position:0% +are interchanged you have to add those +two diagrams + + align:start position:0% +two diagrams + + + align:start position:0% +two diagrams +you know you have to add all matrix + + align:start position:0% +you know you have to add all matrix + + + align:start position:0% +you know you have to add all matrix +elements together + + align:start position:0% +elements together + + + align:start position:0% +elements together +before we calculate an amplitude but you + + align:start position:0% +before we calculate an amplitude but you + + + align:start position:0% +before we calculate an amplitude but you +have to introduce a minus sign when you + + align:start position:0% +have to introduce a minus sign when you + + + align:start position:0% +have to introduce a minus sign when you +change + + align:start position:0% +change + + + align:start position:0% +change +those two particles so with that we have + + align:start position:0% +those two particles so with that we have + + + align:start position:0% +those two particles so with that we have +we can now + + align:start position:0% +we can now + + + align:start position:0% +we can now +just basically calculate whatever qd + + align:start position:0% +just basically calculate whatever qd + + + align:start position:0% +just basically calculate whatever qd +process we want + + align:start position:0% +process we want + + + align:start position:0% +process we want +all the tools are already here and what + + align:start position:0% +all the tools are already here and what + + + align:start position:0% +all the tools are already here and what +we want to do now next in the next video + + align:start position:0% +we want to do now next in the next video + + + align:start position:0% +we want to do now next in the next video +also in the in the recitation and + + align:start position:0% +also in the in the recitation and + + + align:start position:0% +also in the in the recitation and +homework + + align:start position:0% +homework + + + align:start position:0% +homework +is to go through a few examples to get a + + align:start position:0% +is to go through a few examples to get a + + + align:start position:0% +is to go through a few examples to get a +little practice with this + + align:start position:0% +little practice with this + + + align:start position:0% +little practice with this +there's a number of tricks um which will + + align:start position:0% +there's a number of tricks um which will + + + align:start position:0% +there's a number of tricks um which will +become handy and i explain those in a + + align:start position:0% +become handy and i explain those in a + + + align:start position:0% +become handy and i explain those in a +separate video + + align:start position:0% +separate video + + + align:start position:0% +separate video +they're just mathematical tricks which + + align:start position:0% +they're just mathematical tricks which + + + align:start position:0% +they're just mathematical tricks which +allow us to quickly evaluate + + align:start position:0% +allow us to quickly evaluate + + + align:start position:0% +allow us to quickly evaluate +the multiplication of spinos and matrix + + align:start position:0% +the multiplication of spinos and matrix + + + align:start position:0% +the multiplication of spinos and matrix +elements and so on + + align:start position:0% +elements and so on + + + align:start position:0% +elements and so on +all right that's it for this video + + align:start position:0% +all right that's it for this video + + + align:start position:0% +all right that's it for this video +um again there's going to be another two + + align:start position:0% +um again there's going to be another two + + + align:start position:0% +um again there's going to be another two +or three videos which deal with + + align:start position:0% +or three videos which deal with + + + align:start position:0% +or three videos which deal with +actually evaluating or calculating + + align:start position:0% +actually evaluating or calculating + + + align:start position:0% +actually evaluating or calculating +matrix elements \ No newline at end of file diff --git a/83lPKkTfGlY.txt b/83lPKkTfGlY.txt new file mode 100644 index 0000000000000000000000000000000000000000..266a55750913568d53d46451e2c0a4cfa60b2aee --- /dev/null +++ b/83lPKkTfGlY.txt @@ -0,0 +1,2355 @@ +align:start position:0% + +so let's do a connection formula and use + + align:start position:0% +so let's do a connection formula and use + + + align:start position:0% +so let's do a connection formula and use +it to solve a problem the derivation of + + align:start position:0% +it to solve a problem the derivation of + + + align:start position:0% +it to solve a problem the derivation of +such connection formers we'll face it + + align:start position:0% +such connection formers we'll face it + + + align:start position:0% +such connection formers we'll face it +next time and we'll do further + + align:start position:0% +next time and we'll do further + + + align:start position:0% +next time and we'll do further +applications of the methods so yes right + + align:start position:0% +applications of the methods so yes right + + + align:start position:0% +applications of the methods so yes right +this is not a problem of the + + align:start position:0% +this is not a problem of the + + + align:start position:0% +this is not a problem of the +perturbation theory it's just our lack + + align:start position:0% +perturbation theory it's just our lack + + + align:start position:0% +perturbation theory it's just our lack +of ignore a lot of knowledge our + + align:start position:0% +of ignore a lot of knowledge our + + + align:start position:0% +of ignore a lot of knowledge our +ignorance of how the solution looks near + + align:start position:0% +ignorance of how the solution looks near + + + align:start position:0% +ignorance of how the solution looks near +there so there's nice wkb formulas for + + align:start position:0% +there so there's nice wkb formulas for + + + align:start position:0% +there so there's nice wkb formulas for +the solution away from the turning + + align:start position:0% +the solution away from the turning + + + align:start position:0% +the solution away from the turning +points those are this but the solutions + + align:start position:0% +points those are this but the solutions + + + align:start position:0% +points those are this but the solutions +near the turning points violate the + + align:start position:0% +near the turning points violate the + + + align:start position:0% +near the turning points violate the +semi-classical approximation therefore + + align:start position:0% +semi-classical approximation therefore + + + align:start position:0% +semi-classical approximation therefore +you have to find the solution near the + + align:start position:0% +you have to find the solution near the + + + align:start position:0% +you have to find the solution near the +turning points by any method you have + + align:start position:0% +turning points by any method you have + + + align:start position:0% +turning points by any method you have +there is not be gonna be the + + align:start position:0% +there is not be gonna be the + + + align:start position:0% +there is not be gonna be the +semi-classical method and then you will + + align:start position:0% +semi-classical method and then you will + + + align:start position:0% +semi-classical method and then you will +find the continuation now there's + + align:start position:0% +find the continuation now there's + + + align:start position:0% +find the continuation now there's +several ways people do this the most + + align:start position:0% +several ways people do this the most + + + align:start position:0% +several ways people do this the most +down-to-earth method would you say think + + align:start position:0% +down-to-earth method would you say think + + + align:start position:0% +down-to-earth method would you say think +the method we're going to use next time + + align:start position:0% +the method we're going to use next time + + + align:start position:0% +the method we're going to use next time +it's trying to solve the thing near + + align:start position:0% +it's trying to solve the thing near + + + align:start position:0% +it's trying to solve the thing near +there the solution people that are more + + align:start position:0% +there the solution people that are more + + + align:start position:0% +there the solution people that are more +sophisticated use complex variables + + align:start position:0% +sophisticated use complex variables + + + align:start position:0% +sophisticated use complex variables +methods in which they think of the + + align:start position:0% +methods in which they think of the + + + align:start position:0% +methods in which they think of the +solution in the complex plane the X + + align:start position:0% +solution in the complex plane the X + + + align:start position:0% +solution in the complex plane the X +plane becomes complex and they're coming + + align:start position:0% +plane becomes complex and they're coming + + + align:start position:0% +plane becomes complex and they're coming +to the turning point that they go off + + align:start position:0% +to the turning point that they go off + + + align:start position:0% +to the turning point that they go off +the imaginary axis to avoid it and come + + align:start position:0% +the imaginary axis to avoid it and come + + + align:start position:0% +the imaginary axis to avoid it and come +on the other side it's very elegant very + + align:start position:0% +on the other side it's very elegant very + + + align:start position:0% +on the other side it's very elegant very +nice harder to make read very precise + + align:start position:0% +nice harder to make read very precise + + + align:start position:0% +nice harder to make read very precise +and a little difficult to explain I + + align:start position:0% +and a little difficult to explain I + + + align:start position:0% +and a little difficult to explain I +don't know if I'll try to do + + align:start position:0% +don't know if I'll try to do + + + align:start position:0% +don't know if I'll try to do +but it's a it's a nice thing it's sort + + align:start position:0% +but it's a it's a nice thing it's sort + + + align:start position:0% +but it's a it's a nice thing it's sort +of avoiding the turning point by going + + align:start position:0% +of avoiding the turning point by going + + + align:start position:0% +of avoiding the turning point by going +off the axis it sounds crazy so here is + + align:start position:0% +off the axis it sounds crazy so here is + + + align:start position:0% +off the axis it sounds crazy so here is +a turning a connection formula here is x + + align:start position:0% +a turning a connection formula here is x + + + align:start position:0% +a turning a connection formula here is x +equals a here is V of X and here is a + + align:start position:0% +equals a here is V of X and here is a + + + align:start position:0% +equals a here is V of X and here is a +solution for X less than a little a I'll + + align:start position:0% +solution for X less than a little a I'll + + + align:start position:0% +solution for X less than a little a I'll +write it like that P of X cosine X to a + + align:start position:0% +write it like that P of X cosine X to a + + + align:start position:0% +write it like that P of X cosine X to a +Kappa K of X to the X prime minus PI + + align:start position:0% +Kappa K of X to the X prime minus PI + + + align:start position:0% +Kappa K of X to the X prime minus PI +over 4 minus B over square root of P of + + align:start position:0% +over 4 minus B over square root of P of + + + align:start position:0% +over 4 minus B over square root of P of +K of X K of X sine X to a K of X prime + + align:start position:0% +K of X K of X sine X to a K of X prime + + + align:start position:0% +K of X K of X sine X to a K of X prime +VX prime minus PI over 4 so look this is + + align:start position:0% +VX prime minus PI over 4 so look this is + + + align:start position:0% +VX prime minus PI over 4 so look this is +a general solution in allowed region no + + align:start position:0% +a general solution in allowed region no + + + align:start position:0% +a general solution in allowed region no +it doesn't look like what you wrote here + + align:start position:0% +it doesn't look like what you wrote here + + + align:start position:0% +it doesn't look like what you wrote here +but sines and cosines are linear + + align:start position:0% +but sines and cosines are linear + + + align:start position:0% +but sines and cosines are linear +combinations of these things and why do + + align:start position:0% +combinations of these things and why do + + + align:start position:0% +combinations of these things and why do +I put this silly minus PI over 4 because + + align:start position:0% +I put this silly minus PI over 4 because + + + align:start position:0% +I put this silly minus PI over 4 because +that's what nice solutions connect to + + align:start position:0% +that's what nice solutions connect to + + + align:start position:0% +that's what nice solutions connect to +solutions on the other side which is to + + align:start position:0% +solutions on the other side which is to + + + align:start position:0% +solutions on the other side which is to +say that the solution on the other side + + align:start position:0% +say that the solution on the other side + + + align:start position:0% +say that the solution on the other side +people that work this connection + + align:start position:0% +people that work this connection + + + align:start position:0% +people that work this connection +formulas discovered that takes this form + + align:start position:0% + + + + align:start position:0% + +a 2x Kappa of X Prime the X prime plus B + + align:start position:0% +a 2x Kappa of X Prime the X prime plus B + + + align:start position:0% +a 2x Kappa of X Prime the X prime plus B +over square root of Kappa of X e + + align:start position:0% + + + + align:start position:0% + +exponential a 2x top of X prime VX prime + + align:start position:0% + + + + align:start position:0% + +so here it is those numbers a and B are + + align:start position:0% +so here it is those numbers a and B are + + + align:start position:0% +so here it is those numbers a and B are +things you have to keep track now they + + align:start position:0% +things you have to keep track now they + + + align:start position:0% +things you have to keep track now they +say if your solution for + + align:start position:0% +say if your solution for + + + align:start position:0% +say if your solution for +greater than a has this decaying + + align:start position:0% +greater than a has this decaying + + + align:start position:0% +greater than a has this decaying +explanation this grown exponential with + + align:start position:0% +explanation this grown exponential with + + + align:start position:0% +explanation this grown exponential with +B and a your solution far to the left + + align:start position:0% +B and a your solution far to the left + + + align:start position:0% +B and a your solution far to the left +will look like this it's a pretty + + align:start position:0% +will look like this it's a pretty + + + align:start position:0% +will look like this it's a pretty +strange statement sometimes you don't + + align:start position:0% +strange statement sometimes you don't + + + align:start position:0% +strange statement sometimes you don't +want B to be 0 sometimes you do let's do + + align:start position:0% +want B to be 0 sometimes you do let's do + + + align:start position:0% +want B to be 0 sometimes you do let's do +an example with this stuff so that you + + align:start position:0% +an example with this stuff so that you + + + align:start position:0% +an example with this stuff so that you +can appreciate what goes on + + align:start position:0% + + + + align:start position:0% + +so that's your first look at the + + align:start position:0% +so that's your first look at the + + + align:start position:0% +so that's your first look at the +connection condition there's a little + + align:start position:0% +connection condition there's a little + + + align:start position:0% +connection condition there's a little +bit of subtleties and how to use them we + + align:start position:0% +bit of subtleties and how to use them we + + + align:start position:0% +bit of subtleties and how to use them we +will discuss those subtleties next time + + align:start position:0% +will discuss those subtleties next time + + + align:start position:0% +will discuss those subtleties next time +as well but let's use it in a case where + + align:start position:0% +as well but let's use it in a case where + + + align:start position:0% +as well but let's use it in a case where +we can make sense of this without too + + align:start position:0% +we can make sense of this without too + + + align:start position:0% +we can make sense of this without too +much trouble so here is the example and + + align:start position:0% +much trouble so here is the example and + + + align:start position:0% +much trouble so here is the example and +somebody what wants you to solve the + + align:start position:0% +somebody what wants you to solve the + + + align:start position:0% +somebody what wants you to solve the +following problem you have a some slowly + + align:start position:0% +following problem you have a some slowly + + + align:start position:0% +following problem you have a some slowly +varying potential that grows grows + + align:start position:0% +varying potential that grows grows + + + align:start position:0% +varying potential that grows grows +indefinitely the effect and you wish to + + align:start position:0% +indefinitely the effect and you wish to + + + align:start position:0% +indefinitely the effect and you wish to +find the energy eigenstates in + + align:start position:0% +find the energy eigenstates in + + + align:start position:0% +find the energy eigenstates in +particular you wish to find the energies + + align:start position:0% +particular you wish to find the energies + + + align:start position:0% +particular you wish to find the energies +what are the possible energies of this + + align:start position:0% +what are the possible energies of this + + + align:start position:0% +what are the possible energies of this +potential this potential will have a + + align:start position:0% +potential this potential will have a + + + align:start position:0% +potential this potential will have a +infinite wall here so potential is + + align:start position:0% +infinite wall here so potential is + + + align:start position:0% +infinite wall here so potential is +infinite here and it grows like that up + + align:start position:0% +infinite here and it grows like that up + + + align:start position:0% +infinite here and it grows like that up +on this side we're going to try to write + + align:start position:0% +on this side we're going to try to write + + + align:start position:0% +on this side we're going to try to write +the solution for this so we'll do this + + align:start position:0% + + + + align:start position:0% + +with the wkb solution and let me do it + + align:start position:0% +with the wkb solution and let me do it + + + align:start position:0% +with the wkb solution and let me do it +in an efficient way so what do we have + + align:start position:0% +in an efficient way so what do we have + + + align:start position:0% +in an efficient way so what do we have +here this is the analog of our point x + + align:start position:0% +here this is the analog of our point x + + + align:start position:0% +here this is the analog of our point x +equals a is the write this is the point + + align:start position:0% +equals a is the write this is the point + + + align:start position:0% +equals a is the write this is the point +where the turning solution goes funny so + + align:start position:0% +where the turning solution goes funny so + + + align:start position:0% +where the turning solution goes funny so +we will call it for the same reason with + + align:start position:0% +we will call it for the same reason with + + + align:start position:0% +we will call it for the same reason with +it before this point a will make matters + + align:start position:0% +it before this point a will make matters + + + align:start position:0% +it before this point a will make matters +clear + + align:start position:0% + + + + align:start position:0% + +we truly don't know what that point is + + align:start position:0% +we truly don't know what that point is + + + align:start position:0% +we truly don't know what that point is +because we truly don't know what are + + align:start position:0% +because we truly don't know what are + + + align:start position:0% +because we truly don't know what are +they allow energies but so far we can + + align:start position:0% +they allow energies but so far we can + + + align:start position:0% +they allow energies but so far we can +write E is a variable that we don't know + + align:start position:0% +write E is a variable that we don't know + + + align:start position:0% +write E is a variable that we don't know +and a can be determined if you know E + + align:start position:0% +and a can be determined if you know E + + + align:start position:0% +and a can be determined if you know E +because you know the shape of the + + align:start position:0% +because you know the shape of the + + + align:start position:0% +because you know the shape of the +potential okay so let's think of the + + align:start position:0% +potential okay so let's think of the + + + align:start position:0% +potential okay so let's think of the +region X much greater than a we're here + + align:start position:0% +region X much greater than a we're here + + + align:start position:0% +region X much greater than a we're here +we're in a forbidden region and the + + align:start position:0% +we're in a forbidden region and the + + + align:start position:0% +we're in a forbidden region and the +potential is still slowly varying let's + + align:start position:0% +potential is still slowly varying let's + + + align:start position:0% +potential is still slowly varying let's +assume that slope is small so a solution + + align:start position:0% +assume that slope is small so a solution + + + align:start position:0% +assume that slope is small so a solution +of this type would make sense so we must + + align:start position:0% +of this type would make sense so we must + + + align:start position:0% +of this type would make sense so we must +have a wkb solution on this right-hand + + align:start position:0% +have a wkb solution on this right-hand + + + align:start position:0% +have a wkb solution on this right-hand +side to the right of a of x equals a and + + align:start position:0% +side to the right of a of x equals a and + + + align:start position:0% +side to the right of a of x equals a and +that's the most general solution will + + align:start position:0% +that's the most general solution will + + + align:start position:0% +that's the most general solution will +have on the other hand here there's two + + align:start position:0% +have on the other hand here there's two + + + align:start position:0% +have on the other hand here there's two +types of solutions a growing exponential + + align:start position:0% +types of solutions a growing exponential + + + align:start position:0% +types of solutions a growing exponential +and a decaying exponential and we must + + align:start position:0% +and a decaying exponential and we must + + + align:start position:0% +and a decaying exponential and we must +have only the decaying exponential + + align:start position:0% +have only the decaying exponential + + + align:start position:0% +have only the decaying exponential +because this potential never turns if + + align:start position:0% +because this potential never turns if + + + align:start position:0% +because this potential never turns if +this potential would grow here and then + + align:start position:0% +this potential would grow here and then + + + align:start position:0% +this potential would grow here and then +turn down you might have what is called + + align:start position:0% +turn down you might have what is called + + + align:start position:0% +turn down you might have what is called +the tunneling problem and this has to be + + align:start position:0% +the tunneling problem and this has to be + + + align:start position:0% +the tunneling problem and this has to be +rethought but this probably still a + + align:start position:0% +rethought but this probably still a + + + align:start position:0% +rethought but this probably still a +little easier we have just this + + align:start position:0% +little easier we have just this + + + align:start position:0% +little easier we have just this +potential growing forever and on the + + align:start position:0% +potential growing forever and on the + + + align:start position:0% +potential growing forever and on the +right we must have B equal to zero for X + + align:start position:0% +right we must have B equal to zero for X + + + align:start position:0% +right we must have B equal to zero for X +greater than a solution B is equal to 0 + + align:start position:0% +greater than a solution B is equal to 0 + + + align:start position:0% +greater than a solution B is equal to 0 +the solution must have a different from + + align:start position:0% +the solution must have a different from + + + align:start position:0% +the solution must have a different from +0 but if the solution has a different + + align:start position:0% +0 but if the solution has a different + + + align:start position:0% +0 but if the solution has a different +from 0 we now know the solution on this + + align:start position:0% +from 0 we now know the solution on this + + + align:start position:0% +from 0 we now know the solution on this +region X less significantly less than a + + align:start position:0% +region X less significantly less than a + + + align:start position:0% +region X less significantly less than a +in this region we know the solution is + + align:start position:0% +in this region we know the solution is + + + align:start position:0% +in this region we know the solution is +given + + align:start position:0% +given + + + align:start position:0% +given +by that formula up there so our solution + + align:start position:0% +by that formula up there so our solution + + + align:start position:0% +by that formula up there so our solution +for X much less than a the solution must + + align:start position:0% +for X much less than a the solution must + + + align:start position:0% +for X much less than a the solution must +take the form whatever a is one two + + align:start position:0% +take the form whatever a is one two + + + align:start position:0% +take the form whatever a is one two +three I don't I kind of normalize these + + align:start position:0% +three I don't I kind of normalize these + + + align:start position:0% +three I don't I kind of normalize these +things yet + + align:start position:0% +things yet + + + align:start position:0% +things yet +so the solution I'll write its I effects + + align:start position:0% +so the solution I'll write its I effects + + + align:start position:0% +so the solution I'll write its I effects +will be of the form 1 over square root + + align:start position:0% +will be of the form 1 over square root + + + align:start position:0% +will be of the form 1 over square root +of K of X cosine of X to a K of X prime + + align:start position:0% +of K of X cosine of X to a K of X prime + + + align:start position:0% +of K of X cosine of X to a K of X prime +VX prime minus PI over 4 all right + + align:start position:0% +VX prime minus PI over 4 all right + + + align:start position:0% +VX prime minus PI over 4 all right +that's what wkb predicts because of the + + align:start position:0% +that's what wkb predicts because of the + + + align:start position:0% +that's what wkb predicts because of the +connection condition on the forbidden + + align:start position:0% +connection condition on the forbidden + + + align:start position:0% +connection condition on the forbidden +region you know which wave exists and + + align:start position:0% +region you know which wave exists and + + + align:start position:0% +region you know which wave exists and +therefore far to the left of the turning + + align:start position:0% +therefore far to the left of the turning + + + align:start position:0% +therefore far to the left of the turning +point you'd also know the wave function + + align:start position:0% +point you'd also know the wave function + + + align:start position:0% +point you'd also know the wave function +it's the term with an A so have we + + align:start position:0% +it's the term with an A so have we + + + align:start position:0% +it's the term with an A so have we +solved the problem well I don't think we + + align:start position:0% +solved the problem well I don't think we + + + align:start position:0% +solved the problem well I don't think we +have we still don't know the energy so + + align:start position:0% +have we still don't know the energy so + + + align:start position:0% +have we still don't know the energy so +we must have not solved it in fact it + + align:start position:0% +we must have not solved it in fact it + + + align:start position:0% +we must have not solved it in fact it +doesn't look like we've solved it at all + + align:start position:0% +doesn't look like we've solved it at all + + + align:start position:0% +doesn't look like we've solved it at all +because at x equals 0 this wave function + + align:start position:0% +because at x equals 0 this wave function + + + align:start position:0% +because at x equals 0 this wave function +should vanish because there's a hard + + align:start position:0% +should vanish because there's a hard + + + align:start position:0% +should vanish because there's a hard +wall and I don't see any reason why it + + align:start position:0% +wall and I don't see any reason why it + + + align:start position:0% +wall and I don't see any reason why it +would vanish so let's do a little work + + align:start position:0% +would vanish so let's do a little work + + + align:start position:0% +would vanish so let's do a little work +here orienting this expanding this and + + align:start position:0% +here orienting this expanding this and + + + align:start position:0% +here orienting this expanding this and +orienting it a little better so I want + + align:start position:0% +orienting it a little better so I want + + + align:start position:0% +orienting it a little better so I want +to write this integral from 0 X to a + + align:start position:0% +to write this integral from 0 X to a + + + align:start position:0% +to write this integral from 0 X to a +you're having an integral you have 0 X + + align:start position:0% +you're having an integral you have 0 X + + + align:start position:0% +you're having an integral you have 0 X +and a because we are in the X less than + + align:start position:0% +and a because we are in the X less than + + + align:start position:0% +and a because we are in the X less than +a region this integral is the one that + + align:start position:0% +a region this integral is the one that + + + align:start position:0% +a region this integral is the one that +we have here I'll write it as an + + align:start position:0% +we have here I'll write it as an + + + align:start position:0% +we have here I'll write it as an +integral from 0 to a minus an integral + + align:start position:0% +integral from 0 to a minus an integral + + + align:start position:0% +integral from 0 to a minus an integral +from 0 to + + align:start position:0% +from 0 to + + + align:start position:0% +from 0 to +so integral from X to a is equal to an + + align:start position:0% +so integral from X to a is equal to an + + + align:start position:0% +so integral from X to a is equal to an +integral from 0 to a - an integral from + + align:start position:0% +integral from 0 to a - an integral from + + + align:start position:0% +integral from 0 to a - an integral from +0 to X this will make things a little + + align:start position:0% +0 to X this will make things a little + + + align:start position:0% +0 to X this will make things a little +clearer + + align:start position:0% + + + + align:start position:0% + +so in fact we could do things still a + + align:start position:0% +so in fact we could do things still a + + + align:start position:0% +so in fact we could do things still a +little easier so what do we have here we + + align:start position:0% +little easier so what do we have here we + + + align:start position:0% +little easier so what do we have here we +have this exponential the wave function + + align:start position:0% +have this exponential the wave function + + + align:start position:0% +have this exponential the wave function +not an exponential trigonometric + + align:start position:0% +not an exponential trigonometric + + + align:start position:0% +not an exponential trigonometric +function 1 over square root of K of X + + align:start position:0% +function 1 over square root of K of X + + + align:start position:0% +function 1 over square root of K of X +cosine of minus the integral from 0 to X + + align:start position:0% +cosine of minus the integral from 0 to X + + + align:start position:0% +cosine of minus the integral from 0 to X +of K of X DX Prime that's this integral + + align:start position:0% +of K of X DX Prime that's this integral + + + align:start position:0% +of K of X DX Prime that's this integral +gives rise to two in the Wilson I wrote + + align:start position:0% +gives rise to two in the Wilson I wrote + + + align:start position:0% +gives rise to two in the Wilson I wrote +the first then I come with the other + + align:start position:0% +the first then I come with the other + + + align:start position:0% +the first then I come with the other +sign plus the integral from 0 to a of K + + align:start position:0% +sign plus the integral from 0 to a of K + + + align:start position:0% +sign plus the integral from 0 to a of K +prime of X DX prime minus PI over 4 and + + align:start position:0% +prime of X DX prime minus PI over 4 and + + + align:start position:0% +prime of X DX prime minus PI over 4 and +let's call this thing Delta ok + + align:start position:0% + + + + align:start position:0% + +so let's explore this wave function a + + align:start position:0% +so let's explore this wave function a + + + align:start position:0% +so let's explore this wave function a +little more so things have become kind + + align:start position:0% +little more so things have become kind + + + align:start position:0% +little more so things have become kind +of nice there's no X dependence here + + align:start position:0% +of nice there's no X dependence here + + + align:start position:0% +of nice there's no X dependence here +that's very nice about this part of the + + align:start position:0% +that's very nice about this part of the + + + align:start position:0% +that's very nice about this part of the +formula this is an angle no exponents + + align:start position:0% +formula this is an angle no exponents + + + align:start position:0% +formula this is an angle no exponents +and the X dependence is just here from + + align:start position:0% +and the X dependence is just here from + + + align:start position:0% +and the X dependence is just here from +this term and it's a nice X dependence + + align:start position:0% +this term and it's a nice X dependence + + + align:start position:0% +this term and it's a nice X dependence +because it's an interval + + align:start position:0% +because it's an interval + + + align:start position:0% +because it's an interval +from zero to X so it kind of nice the + + align:start position:0% +from zero to X so it kind of nice the + + + align:start position:0% +from zero to X so it kind of nice the +upper limit has the X it's all kind of + + align:start position:0% +upper limit has the X it's all kind of + + + align:start position:0% +upper limit has the X it's all kind of +elegant so trigonometric function of + + align:start position:0% +elegant so trigonometric function of + + + align:start position:0% +elegant so trigonometric function of +this cosine of a difference of things is + + align:start position:0% +this cosine of a difference of things is + + + align:start position:0% +this cosine of a difference of things is +equal to 2a muscle it's cosine of the + + align:start position:0% +equal to 2a muscle it's cosine of the + + + align:start position:0% +equal to 2a muscle it's cosine of the +first term 0 to X K of X prime DX prime + + align:start position:0% +first term 0 to X K of X prime DX prime + + + align:start position:0% +first term 0 to X K of X prime DX prime +cosine Delta plus sine of the first term + + align:start position:0% +cosine Delta plus sine of the first term + + + align:start position:0% +cosine Delta plus sine of the first term +0 to X K of X prime DX prime sine Delta + + align:start position:0% + + + + align:start position:0% + +you have this quantity and this Delta so + + align:start position:0% +you have this quantity and this Delta so + + + align:start position:0% +you have this quantity and this Delta so +I use this trigonometric sum + + align:start position:0% +I use this trigonometric sum + + + align:start position:0% +I use this trigonometric sum +okay but now you can see something nice + + align:start position:0% + + + + align:start position:0% + +what did we say about the wave function + + align:start position:0% +what did we say about the wave function + + + align:start position:0% +what did we say about the wave function +it had to vanish at the origin and let's + + align:start position:0% +it had to vanish at the origin and let's + + + align:start position:0% +it had to vanish at the origin and let's +look at these two functions which one + + align:start position:0% +look at these two functions which one + + + align:start position:0% +look at these two functions which one +vanishes at the origin you have cosine + + align:start position:0% +vanishes at the origin you have cosine + + + align:start position:0% +vanishes at the origin you have cosine +of the inter from 0 to X when X is equal + + align:start position:0% +of the inter from 0 to X when X is equal + + + align:start position:0% +of the inter from 0 to X when X is equal +to 0 at the origin this cosine of 0 + + align:start position:0% +to 0 at the origin this cosine of 0 + + + align:start position:0% +to 0 at the origin this cosine of 0 +which is 1 on the other hand when X is + + align:start position:0% +which is 1 on the other hand when X is + + + align:start position:0% +which is 1 on the other hand when X is +smaller X goes to 0 you get 0 for the + + align:start position:0% +smaller X goes to 0 you get 0 for the + + + align:start position:0% +smaller X goes to 0 you get 0 for the +integral and the sine vanishes so this + + align:start position:0% +integral and the sine vanishes so this + + + align:start position:0% +integral and the sine vanishes so this +is the right term so this wave function + + align:start position:0% +is the right term so this wave function + + + align:start position:0% +is the right term so this wave function +would be correct if this term would be + + align:start position:0% +would be correct if this term would be + + + align:start position:0% +would be correct if this term would be +absent this is a term that you must make + + align:start position:0% +absent this is a term that you must make + + + align:start position:0% +absent this is a term that you must make +absent shy of X without that term would + + align:start position:0% +absent shy of X without that term would + + + align:start position:0% +absent shy of X without that term would +be a valid wave function it is the wave + + align:start position:0% +be a valid wave function it is the wave + + + align:start position:0% +be a valid wave function it is the wave +function + + align:start position:0% +function + + + align:start position:0% +function +therefore the right way function if we + + align:start position:0% +therefore the right way function if we + + + align:start position:0% +therefore the right way function if we +demand that cosine Delta be equal to + + align:start position:0% +demand that cosine Delta be equal to + + + align:start position:0% +demand that cosine Delta be equal to +zero so now we're imposing as something + + align:start position:0% +zero so now we're imposing as something + + + align:start position:0% +zero so now we're imposing as something +a very non trivial condition this wave + + align:start position:0% +a very non trivial condition this wave + + + align:start position:0% +a very non trivial condition this wave +over there this contribution to the + + align:start position:0% +over there this contribution to the + + + align:start position:0% +over there this contribution to the +argument to the angle here this Delta + + align:start position:0% +argument to the angle here this Delta + + + align:start position:0% +argument to the angle here this Delta +must be such that cosine Delta is 0 in + + align:start position:0% +must be such that cosine Delta is 0 in + + + align:start position:0% +must be such that cosine Delta is 0 in +which case this term would disappear and + + align:start position:0% +which case this term would disappear and + + + align:start position:0% +which case this term would disappear and +we would have a good wave function Phi + + align:start position:0% +we would have a good wave function Phi + + + align:start position:0% +we would have a good wave function Phi +of X if this is true is 1 over square + + align:start position:0% +of X if this is true is 1 over square + + + align:start position:0% +of X if this is true is 1 over square +root of K of X times sine times the sine + + align:start position:0% +root of K of X times sine times the sine + + + align:start position:0% +root of K of X times sine times the sine +Delta which is another number sine of 0 + + align:start position:0% +Delta which is another number sine of 0 + + + align:start position:0% +Delta which is another number sine of 0 +to X K of X prime D X PRIZE so we need + + align:start position:0% +to X K of X prime D X PRIZE so we need + + + align:start position:0% +to X K of X prime D X PRIZE so we need +cosine Delta equal to 0 + + align:start position:0% +cosine Delta equal to 0 + + + align:start position:0% +cosine Delta equal to 0 +you know this argument gives you this + + align:start position:0% +you know this argument gives you this + + + align:start position:0% +you know this argument gives you this +wave function in a nice way here written + + align:start position:0% +wave function in a nice way here written + + + align:start position:0% +wave function in a nice way here written +what it is but we would have been able + + align:start position:0% +what it is but we would have been able + + + align:start position:0% +what it is but we would have been able +to find this or even faster if you just + + align:start position:0% +to find this or even faster if you just + + + align:start position:0% +to find this or even faster if you just +beam and that sigh at x equals 0 is 0 + + align:start position:0% +beam and that sigh at x equals 0 is 0 + + + align:start position:0% +beam and that sigh at x equals 0 is 0 +you must have that this thing the inter + + align:start position:0% +you must have that this thing the inter + + + align:start position:0% +you must have that this thing the inter +from 0 to a of this quantity minus PI + + align:start position:0% +from 0 to a of this quantity minus PI + + + align:start position:0% +from 0 to a of this quantity minus PI +over 4 + + align:start position:0% +over 4 + + + align:start position:0% +over 4 +must have 0 cosine and that's the + + align:start position:0% +must have 0 cosine and that's the + + + align:start position:0% +must have 0 cosine and that's the +condition we did find the advantage of + + align:start position:0% +condition we did find the advantage of + + + align:start position:0% +condition we did find the advantage of +our rearrangement is that when that + + align:start position:0% +our rearrangement is that when that + + + align:start position:0% +our rearrangement is that when that +happens the whole wave function looks + + align:start position:0% +happens the whole wave function looks + + + align:start position:0% +happens the whole wave function looks +like that and that's kind of nice that + + align:start position:0% +like that and that's kind of nice that + + + align:start position:0% +like that and that's kind of nice that +gives you the picture of the wave + + align:start position:0% +gives you the picture of the wave + + + align:start position:0% +gives you the picture of the wave +function a fairly accurate picture of + + align:start position:0% +function a fairly accurate picture of + + + align:start position:0% +function a fairly accurate picture of +the wave function in this region not + + align:start position:0% +the wave function in this region not + + + align:start position:0% +the wave function in this region not +very near the turning point but you dot + + align:start position:0% +very near the turning point but you dot + + + align:start position:0% +very near the turning point but you dot +that so so what is this cosine Delta + + align:start position:0% +that so so what is this cosine Delta + + + align:start position:0% +that so so what is this cosine Delta +going to 0 + + align:start position:0% +going to 0 + + + align:start position:0% +going to 0 +well then Delta must be 2 and plus 1 + + align:start position:0% +well then Delta must be 2 and plus 1 + + + align:start position:0% +well then Delta must be 2 and plus 1 +times pi over 2 so the places where the + + align:start position:0% +times pi over 2 so the places where the + + + align:start position:0% +times pi over 2 so the places where the +cosine is 0 is PI over 2 that's for n + + align:start position:0% +cosine is 0 is PI over 2 that's for n + + + align:start position:0% +cosine is 0 is PI over 2 that's for n +equals 0 3 PI over 2 so for m equal 1 + + align:start position:0% +equals 0 3 PI over 2 so for m equal 1 + + + align:start position:0% +equals 0 3 PI over 2 so for m equal 1 +and it just goes the vertical axis and + + align:start position:0% +and it just goes the vertical axis and + + + align:start position:0% +and it just goes the vertical axis and +the unit circle so this is for n equals + + align:start position:0% +the unit circle so this is for n equals + + + align:start position:0% +the unit circle so this is for n equals +0 1 2 3 goes on and on and this is a + + align:start position:0% +0 1 2 3 goes on and on and this is a + + + align:start position:0% +0 1 2 3 goes on and on and this is a +very wonderful condition this says that + + align:start position:0% +very wonderful condition this says that + + + align:start position:0% +very wonderful condition this says that +the integral from 0 to a of K of X prime + + align:start position:0% +the integral from 0 to a of K of X prime + + + align:start position:0% +the integral from 0 to a of K of X prime +DX prime minus PI over 4 so actually we + + align:start position:0% +DX prime minus PI over 4 so actually we + + + align:start position:0% +DX prime minus PI over 4 so actually we +have here you can multiply the two here + + align:start position:0% +have here you can multiply the two here + + + align:start position:0% +have here you can multiply the two here +you get an M and then you have PI over 2 + + align:start position:0% +you get an M and then you have PI over 2 + + + align:start position:0% +you get an M and then you have PI over 2 +and the PI over 4 that comes from that + + align:start position:0% +and the PI over 4 that comes from that + + + align:start position:0% +and the PI over 4 that comes from that +term becomes n plus 3/4 pi it's a bar + + align:start position:0% +term becomes n plus 3/4 pi it's a bar + + + align:start position:0% +term becomes n plus 3/4 pi it's a bar +born Sommerfeld quantization condition + + align:start position:0% +born Sommerfeld quantization condition + + + align:start position:0% +born Sommerfeld quantization condition +look I box that equation because that + + align:start position:0% +look I box that equation because that + + + align:start position:0% +look I box that equation because that +really gives you the answer now why + + align:start position:0% +really gives you the answer now why + + + align:start position:0% +really gives you the answer now why +because you know what K is K P of X is + + align:start position:0% +because you know what K is K P of X is + + + align:start position:0% +because you know what K is K P of X is +equal to H Bar K a square root of 2m e + + align:start position:0% +equal to H Bar K a square root of 2m e + + + align:start position:0% +equal to H Bar K a square root of 2m e +minus V of X and if you know e you know + + align:start position:0% +minus V of X and if you know e you know + + + align:start position:0% +minus V of X and if you know e you know +a so you have now a name to grow and you + + align:start position:0% +a so you have now a name to grow and you + + + align:start position:0% +a so you have now a name to grow and you +take for example N equals 0 so you want + + align:start position:0% +take for example N equals 0 so you want + + + align:start position:0% +take for example N equals 0 so you want +the integral to be equal to 3/4 pi but + + align:start position:0% +the integral to be equal to 3/4 pi but + + + align:start position:0% +the integral to be equal to 3/4 pi but +you will have to start changing the + + align:start position:0% +you will have to start changing the + + + align:start position:0% +you will have to start changing the +value of the energy with your computer + + align:start position:0% +value of the energy with your computer + + + align:start position:0% +value of the energy with your computer +if you cannot do the integral + + align:start position:0% +if you cannot do the integral + + + align:start position:0% +if you cannot do the integral +analytically and find oops for this + + align:start position:0% +analytically and find oops for this + + + align:start position:0% +analytically and find oops for this +value of the energy the integral of what + + align:start position:0% +value of the energy the integral of what + + + align:start position:0% +value of the energy the integral of what +I know this is a known function gives me + + align:start position:0% +I know this is a known function gives me + + + align:start position:0% +I know this is a known function gives me +this value so this is a very practical + + align:start position:0% +this value so this is a very practical + + + align:start position:0% +this value so this is a very practical +way of finding the energy levels it does + + align:start position:0% +way of finding the energy levels it does + + + align:start position:0% +way of finding the energy levels it does +give you the energy of the approximate + + align:start position:0% +give you the energy of the approximate + + + align:start position:0% +give you the energy of the approximate +energy levels and it's remark + + align:start position:0% +energy levels and it's remark + + + align:start position:0% +energy levels and it's remark +accurate in many cases of it also has a + + align:start position:0% +accurate in many cases of it also has a + + + align:start position:0% +accurate in many cases of it also has a +little intuition this is for N equals + + align:start position:0% +little intuition this is for N equals + + + align:start position:0% +little intuition this is for N equals +zero would be like the ground state an + + align:start position:0% +zero would be like the ground state an + + + align:start position:0% +zero would be like the ground state an +equal one first set on excited States + + align:start position:0% +equal one first set on excited States + + + align:start position:0% +equal one first set on excited States +and indeed that makes sense because Z + + align:start position:0% +and indeed that makes sense because Z + + + align:start position:0% +and indeed that makes sense because Z +this integral from 0 to a of K is the + + align:start position:0% +this integral from 0 to a of K is the + + + align:start position:0% +this integral from 0 to a of K is the +total phase of the wave function as you + + align:start position:0% +total phase of the wave function as you + + + align:start position:0% +total phase of the wave function as you +move from zero to a and that wave is a + + align:start position:0% +move from zero to a and that wave is a + + + align:start position:0% +move from zero to a and that wave is a +number of factor n times pi plus a + + align:start position:0% +number of factor n times pi plus a + + + align:start position:0% +number of factor n times pi plus a +little bit so it has time for n zeros + + align:start position:0% +little bit so it has time for n zeros + + + align:start position:0% +little bit so it has time for n zeros +the face as you move from zero to a in + + align:start position:0% +the face as you move from zero to a in + + + align:start position:0% +the face as you move from zero to a in +the wave function will have the sine + + align:start position:0% +the wave function will have the sine + + + align:start position:0% +the wave function will have the sine +function will have n zeros if this + + align:start position:0% +function will have n zeros if this + + + align:start position:0% +function will have n zeros if this +condition is satisfied consistent with + + align:start position:0% +condition is satisfied consistent with + + + align:start position:0% +condition is satisfied consistent with +that solution so that's it we'll + + align:start position:0% +that solution so that's it we'll + + + align:start position:0% +that solution so that's it we'll +continue next time find the solution of + + align:start position:0% +continue next time find the solution of + + + align:start position:0% +continue next time find the solution of +wkb exactly all right \ No newline at end of file diff --git a/8Okyz-5hal0.txt b/8Okyz-5hal0.txt new file mode 100644 index 0000000000000000000000000000000000000000..27c2783a722f6757ae72551554d2cacf45054843 --- /dev/null +++ b/8Okyz-5hal0.txt @@ -0,0 +1,7715 @@ +align:start position:0% + +okay we talked about spinal reflexes + + align:start position:0% +okay we talked about spinal reflexes + + + align:start position:0% +okay we talked about spinal reflexes +last time + + align:start position:0% + + + + align:start position:0% + +this is class 20. the second + + align:start position:0% +this is class 20. the second + + + align:start position:0% +this is class 20. the second +session on the motor system + + align:start position:0% +session on the motor system + + + align:start position:0% +session on the motor system +and we're going to continue talking + + align:start position:0% +and we're going to continue talking + + + align:start position:0% +and we're going to continue talking +about spinal reflexes + + align:start position:0% +about spinal reflexes + + + align:start position:0% +about spinal reflexes +last time + + align:start position:0% +last time + + + align:start position:0% +last time +the slide + + align:start position:0% +the slide + + + align:start position:0% +the slide +that i just mentioned + + align:start position:0% + + + + align:start position:0% + +is this one + + align:start position:0% + + + + align:start position:0% + +right here you can see i had crossed it + + align:start position:0% +right here you can see i had crossed it + + + align:start position:0% +right here you can see i had crossed it +out + + align:start position:0% +out + + + align:start position:0% +out +it says lateral horn + + align:start position:0% +it says lateral horn + + + align:start position:0% +it says lateral horn +it made sense to them that when the + + align:start position:0% +it made sense to them that when the + + + align:start position:0% +it made sense to them that when the +spinal cord looks like that that looks + + align:start position:0% +spinal cord looks like that that looks + + + align:start position:0% +spinal cord looks like that that looks +like it's the lateral horn but this is + + align:start position:0% +like it's the lateral horn but this is + + + align:start position:0% +like it's the lateral horn but this is +actually + + align:start position:0% +actually + + + align:start position:0% +actually +at an enlargement and this is all + + align:start position:0% +at an enlargement and this is all + + + align:start position:0% +at an enlargement and this is all +ventral horn + + align:start position:0% +ventral horn + + + align:start position:0% +ventral horn +the lateral horn is a tiny little + + align:start position:0% +the lateral horn is a tiny little + + + align:start position:0% +the lateral horn is a tiny little +protrusion in the gray matter right at + + align:start position:0% +protrusion in the gray matter right at + + + align:start position:0% +protrusion in the gray matter right at +that location where i'm putting the + + align:start position:0% +that location where i'm putting the + + + align:start position:0% +that location where i'm putting the +cursor + + align:start position:0% +cursor + + + align:start position:0% +cursor +or it would be there + + align:start position:0% +or it would be there + + + align:start position:0% +or it would be there +okay + + align:start position:0% + + + + align:start position:0% + +so these were our + + align:start position:0% +so these were our + + + align:start position:0% +so these were our +slides from last time + + align:start position:0% + + + + align:start position:0% + +and today we're + + align:start position:0% +and today we're + + + align:start position:0% +and today we're +we'll talk about the stretch reflex and + + align:start position:0% +we'll talk about the stretch reflex and + + + align:start position:0% +we'll talk about the stretch reflex and +talk about its function + + align:start position:0% +talk about its function + + + align:start position:0% +talk about its function +then we'll say a little bit about + + align:start position:0% +then we'll say a little bit about + + + align:start position:0% +then we'll say a little bit about +intersegmental organization in the chord + + align:start position:0% +intersegmental organization in the chord + + + align:start position:0% +intersegmental organization in the chord +and then plasticity in the cord + + align:start position:0% +and then plasticity in the cord + + + align:start position:0% +and then plasticity in the cord +and + + align:start position:0% +and + + + align:start position:0% +and +i don't know if we'll get to descending + + align:start position:0% +i don't know if we'll get to descending + + + align:start position:0% +i don't know if we'll get to descending +pathways but we need to cover that + + align:start position:0% +pathways but we need to cover that + + + align:start position:0% +pathways but we need to cover that +before we + + align:start position:0% +before we + + + align:start position:0% +before we +in order to introduce the film that + + align:start position:0% +in order to introduce the film that + + + align:start position:0% +in order to introduce the film that +we're going to see on friday + + align:start position:0% +we're going to see on friday + + + align:start position:0% +we're going to see on friday +okay on the function of descending + + align:start position:0% +okay on the function of descending + + + align:start position:0% +okay on the function of descending +pathways + + align:start position:0% + + + + align:start position:0% + +okay so the stretch reflex + + align:start position:0% + + + + align:start position:0% + +what is it + + align:start position:0% +what is it + + + align:start position:0% +what is it +it's the reflex they always test when + + align:start position:0% +it's the reflex they always test when + + + align:start position:0% +it's the reflex they always test when +the in the neurology clinic + + align:start position:0% +the in the neurology clinic + + + align:start position:0% +the in the neurology clinic +with a jerk of the knee + + align:start position:0% +with a jerk of the knee + + + align:start position:0% +with a jerk of the knee +the knee jerk reflex + + align:start position:0% + + + + align:start position:0% + +now that's just an example of a stretch + + align:start position:0% +now that's just an example of a stretch + + + align:start position:0% +now that's just an example of a stretch +reflex + + align:start position:0% +reflex + + + align:start position:0% +reflex +all your striated muscles have stretch + + align:start position:0% +all your striated muscles have stretch + + + align:start position:0% +all your striated muscles have stretch +reflexes okay + + align:start position:0% +reflexes okay + + + align:start position:0% +reflexes okay +if you suddenly stretch any muscle + + align:start position:0% +if you suddenly stretch any muscle + + + align:start position:0% +if you suddenly stretch any muscle +you get a stretch reflex but ordinarily + + align:start position:0% +you get a stretch reflex but ordinarily + + + align:start position:0% +you get a stretch reflex but ordinarily +this reflex is operating + + align:start position:0% +this reflex is operating + + + align:start position:0% +this reflex is operating +not just the sudden stretches but to any + + align:start position:0% +not just the sudden stretches but to any + + + align:start position:0% +not just the sudden stretches but to any +stretch + + align:start position:0% +stretch + + + align:start position:0% +stretch +okay + + align:start position:0% + + + + align:start position:0% + +and let's talk about that + + align:start position:0% +and let's talk about that + + + align:start position:0% +and let's talk about that +the sensory organ is called the muscle + + align:start position:0% +the sensory organ is called the muscle + + + align:start position:0% +the sensory organ is called the muscle +spindle + + align:start position:0% +spindle + + + align:start position:0% +spindle +it's in the muscle in response to muscle + + align:start position:0% +it's in the muscle in response to muscle + + + align:start position:0% +it's in the muscle in response to muscle +stretch + + align:start position:0% +stretch + + + align:start position:0% +stretch +okay + + align:start position:0% + + + + align:start position:0% + +so this is your textbook picture + + align:start position:0% +so this is your textbook picture + + + align:start position:0% +so this is your textbook picture +it shows a little piece of the biceps + + align:start position:0% +it shows a little piece of the biceps + + + align:start position:0% +it shows a little piece of the biceps +muscle there + + align:start position:0% + + + + align:start position:0% + +and it shows two kinds of sensory + + align:start position:0% +and it shows two kinds of sensory + + + align:start position:0% +and it shows two kinds of sensory +innings there are endings in the tendons + + align:start position:0% +innings there are endings in the tendons + + + align:start position:0% +innings there are endings in the tendons +you see the enlargement here in the + + align:start position:0% +you see the enlargement here in the + + + align:start position:0% +you see the enlargement here in the +upper right + + align:start position:0% +upper right + + + align:start position:0% +upper right +the golgi tendon organ is a + + align:start position:0% + + + + align:start position:0% + +sensory axons that innervate the tendons + + align:start position:0% +sensory axons that innervate the tendons + + + align:start position:0% +sensory axons that innervate the tendons +and respond to tension + + align:start position:0% +and respond to tension + + + align:start position:0% +and respond to tension +in the tendon + + align:start position:0% +in the tendon + + + align:start position:0% +in the tendon +okay so the tighter the muscle + + align:start position:0% +okay so the tighter the muscle + + + align:start position:0% +okay so the tighter the muscle +whether the muscle is short or long + + align:start position:0% +whether the muscle is short or long + + + align:start position:0% +whether the muscle is short or long +doesn't matter if that + + align:start position:0% +doesn't matter if that + + + align:start position:0% +doesn't matter if that +tendon is tight those + + align:start position:0% +tendon is tight those + + + align:start position:0% +tendon is tight those +10 organs will fire and what's its + + align:start position:0% +10 organs will fire and what's its + + + align:start position:0% +10 organs will fire and what's its +function well if the muscle + + align:start position:0% +function well if the muscle + + + align:start position:0% +function well if the muscle +becomes + + align:start position:0% +becomes + + + align:start position:0% +becomes +so + + align:start position:0% +so + + + align:start position:0% +so +tight + + align:start position:0% +tight + + + align:start position:0% +tight +that the muscle that the + + align:start position:0% +that the muscle that the + + + align:start position:0% +that the muscle that the +muscle is endangering itself or + + align:start position:0% +muscle is endangering itself or + + + align:start position:0% +muscle is endangering itself or +endangering the tendons or bones + + align:start position:0% +endangering the tendons or bones + + + align:start position:0% +endangering the tendons or bones +it will cause the muscle to suddenly + + align:start position:0% +it will cause the muscle to suddenly + + + align:start position:0% +it will cause the muscle to suddenly +relax + + align:start position:0% +relax + + + align:start position:0% +relax +okay + + align:start position:0% + + + + align:start position:0% + +that's to protect + + align:start position:0% +that's to protect + + + align:start position:0% +that's to protect +your muscles and limbs + + align:start position:0% +your muscles and limbs + + + align:start position:0% +your muscles and limbs +okay + + align:start position:0% +okay + + + align:start position:0% +okay +but there's also in the muscle in + + align:start position:0% +but there's also in the muscle in + + + align:start position:0% +but there's also in the muscle in +parallel with the long muscle fibers + + align:start position:0% +parallel with the long muscle fibers + + + align:start position:0% +parallel with the long muscle fibers +there's little + + align:start position:0% +there's little + + + align:start position:0% +there's little +slender fibers + + align:start position:0% +slender fibers + + + align:start position:0% +slender fibers +called muscle spindles that contain not + + align:start position:0% +called muscle spindles that contain not + + + align:start position:0% +called muscle spindles that contain not +only muscle fibers + + align:start position:0% +only muscle fibers + + + align:start position:0% +only muscle fibers +much smaller muscle fibers than the + + align:start position:0% +much smaller muscle fibers than the + + + align:start position:0% +much smaller muscle fibers than the +striated muscle fibers that give power + + align:start position:0% +striated muscle fibers that give power + + + align:start position:0% +striated muscle fibers that give power +to the muscle + + align:start position:0% +to the muscle + + + align:start position:0% +to the muscle +but they contain sensory endings so for + + align:start position:0% +but they contain sensory endings so for + + + align:start position:0% +but they contain sensory endings so for +example + + align:start position:0% +example + + + align:start position:0% +example +in blue here they show a large axon that + + align:start position:0% +in blue here they show a large axon that + + + align:start position:0% +in blue here they show a large axon that +comes down and then wraps itself around + + align:start position:0% +comes down and then wraps itself around + + + align:start position:0% +comes down and then wraps itself around +the spindle + + align:start position:0% +the spindle + + + align:start position:0% +the spindle +okay + + align:start position:0% +okay + + + align:start position:0% +okay +it's + + align:start position:0% +it's + + + align:start position:0% +it's +designed to + + align:start position:0% +designed to + + + align:start position:0% +designed to +fire extra potentials when the muscle is + + align:start position:0% +fire extra potentials when the muscle is + + + align:start position:0% +fire extra potentials when the muscle is +stretched + + align:start position:0% +stretched + + + align:start position:0% +stretched +okay then there's a few other endings + + align:start position:0% +okay then there's a few other endings + + + align:start position:0% +okay then there's a few other endings +there + + align:start position:0% +there + + + align:start position:0% +there +and then there's also motor axons the + + align:start position:0% +and then there's also motor axons the + + + align:start position:0% +and then there's also motor axons the +gamma motor fibers + + align:start position:0% +gamma motor fibers + + + align:start position:0% +gamma motor fibers +coming from gamma motor neurons in the + + align:start position:0% +coming from gamma motor neurons in the + + + align:start position:0% +coming from gamma motor neurons in the +ventral horn of the cord + + align:start position:0% +ventral horn of the cord + + + align:start position:0% +ventral horn of the cord +that innervate the muscle fiber + + align:start position:0% +that innervate the muscle fiber + + + align:start position:0% +that innervate the muscle fiber +the + + align:start position:0% +the + + + align:start position:0% +the +intrafusal muscle fiber + + align:start position:0% +intrafusal muscle fiber + + + align:start position:0% +intrafusal muscle fiber +fuse is for the shape + + align:start position:0% +fuse is for the shape + + + align:start position:0% +fuse is for the shape +so it's shaped like a spindle or a fuse + + align:start position:0% +so it's shaped like a spindle or a fuse + + + align:start position:0% +so it's shaped like a spindle or a fuse +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so we call it the intrafusal muscle + + align:start position:0% +so we call it the intrafusal muscle + + + align:start position:0% +so we call it the intrafusal muscle +fiber if it's that fiber that tightens + + align:start position:0% +fiber if it's that fiber that tightens + + + align:start position:0% +fiber if it's that fiber that tightens +up the spindle + + align:start position:0% +up the spindle + + + align:start position:0% +up the spindle +and okay + + align:start position:0% +and okay + + + align:start position:0% +and okay +so let's look at this picture now here + + align:start position:0% +so let's look at this picture now here + + + align:start position:0% +so let's look at this picture now here +they show + + align:start position:0% +they show + + + align:start position:0% +they show +a muscle fiber + + align:start position:0% +a muscle fiber + + + align:start position:0% +a muscle fiber +and a spindle organ which has smaller + + align:start position:0% +and a spindle organ which has smaller + + + align:start position:0% +and a spindle organ which has smaller +muscle fibers in it so this is the main + + align:start position:0% +muscle fibers in it so this is the main + + + align:start position:0% +muscle fibers in it so this is the main +striated muscle fiber + + align:start position:0% +striated muscle fiber + + + align:start position:0% +striated muscle fiber +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and this just represents the attachments + + align:start position:0% +and this just represents the attachments + + + align:start position:0% +and this just represents the attachments +to + + align:start position:0% +to + + + align:start position:0% +to +the bone on either side + + align:start position:0% + + + + align:start position:0% + +now if you stretch the muscle + + align:start position:0% + + + + align:start position:0% + +what happens you stretch the spindle too + + align:start position:0% +what happens you stretch the spindle too + + + align:start position:0% +what happens you stretch the spindle too +okay what will happen is that the + + align:start position:0% +okay what will happen is that the + + + align:start position:0% +okay what will happen is that the +spindle afferent fibers + + align:start position:0% +spindle afferent fibers + + + align:start position:0% +spindle afferent fibers +will start firing so will the gold g10 + + align:start position:0% +will start firing so will the gold g10 + + + align:start position:0% +will start firing so will the gold g10 +an organ + + align:start position:0% +an organ + + + align:start position:0% +an organ +the axons innervating the golgi tender + + align:start position:0% +the axons innervating the golgi tender + + + align:start position:0% +the axons innervating the golgi tender +organ when this just shows when the + + align:start position:0% +organ when this just shows when the + + + align:start position:0% +organ when this just shows when the +stretch occurs so as soon as it's + + align:start position:0% +stretch occurs so as soon as it's + + + align:start position:0% +stretch occurs so as soon as it's +stretched both of those afferents will + + align:start position:0% +stretched both of those afferents will + + + align:start position:0% +stretched both of those afferents will +fire + + align:start position:0% +fire + + + align:start position:0% +fire +okay + + align:start position:0% +okay + + + align:start position:0% +okay +you say well then why did you need two + + align:start position:0% +you say well then why did you need two + + + align:start position:0% +you say well then why did you need two +endings + + align:start position:0% +endings + + + align:start position:0% +endings +well you'll see + + align:start position:0% +well you'll see + + + align:start position:0% +well you'll see +here's a picture of + + align:start position:0% +here's a picture of + + + align:start position:0% +here's a picture of +when the muscle + + align:start position:0% +when the muscle + + + align:start position:0% +when the muscle +is contracted + + align:start position:0% +is contracted + + + align:start position:0% +is contracted +so the alpha motor neurons have fired + + align:start position:0% +so the alpha motor neurons have fired + + + align:start position:0% +so the alpha motor neurons have fired +caused this muscle to shorten okay + + align:start position:0% +caused this muscle to shorten okay + + + align:start position:0% +caused this muscle to shorten okay +when the muscle shortens the golgi + + align:start position:0% +when the muscle shortens the golgi + + + align:start position:0% +when the muscle shortens the golgi +tendon organ of course is going to fire + + align:start position:0% +tendon organ of course is going to fire + + + align:start position:0% +tendon organ of course is going to fire +because of the tension in the muscle but + + align:start position:0% +because of the tension in the muscle but + + + align:start position:0% +because of the tension in the muscle but +now the spindle + + align:start position:0% +now the spindle + + + align:start position:0% +now the spindle +has become relaxed + + align:start position:0% +has become relaxed + + + align:start position:0% +has become relaxed +if the muscle shortens + + align:start position:0% +if the muscle shortens + + + align:start position:0% +if the muscle shortens +the spindle is not stretched so it's + + align:start position:0% +the spindle is not stretched so it's + + + align:start position:0% +the spindle is not stretched so it's +gonna fire very little + + align:start position:0% +gonna fire very little + + + align:start position:0% +gonna fire very little +if at all + + align:start position:0% +if at all + + + align:start position:0% +if at all +okay + + align:start position:0% + + + + align:start position:0% + +that rarely happens except very + + align:start position:0% +that rarely happens except very + + + align:start position:0% +that rarely happens except very +transiently + + align:start position:0% +transiently + + + align:start position:0% +transiently +why + + align:start position:0% +why + + + align:start position:0% +why +because when this muscle contracts + + align:start position:0% +because when this muscle contracts + + + align:start position:0% +because when this muscle contracts +the gamma motor neurons also fire and + + align:start position:0% +the gamma motor neurons also fire and + + + align:start position:0% +the gamma motor neurons also fire and +shorten the spindle + + align:start position:0% +shorten the spindle + + + align:start position:0% +shorten the spindle +to keep it sensitive to stretch + + align:start position:0% +to keep it sensitive to stretch + + + align:start position:0% +to keep it sensitive to stretch +so its length is always being adjusted + + align:start position:0% +so its length is always being adjusted + + + align:start position:0% +so its length is always being adjusted +for the length of the muscle because we + + align:start position:0% +for the length of the muscle because we + + + align:start position:0% +for the length of the muscle because we +want it to be able to respond + + align:start position:0% +want it to be able to respond + + + align:start position:0% +want it to be able to respond +to a stretch + + align:start position:0% +to a stretch + + + align:start position:0% +to a stretch +that wasn't expected + + align:start position:0% +that wasn't expected + + + align:start position:0% +that wasn't expected +okay + + align:start position:0% + + + + align:start position:0% + +and that system for controlling the + + align:start position:0% +and that system for controlling the + + + align:start position:0% +and that system for controlling the +length of the spindle we call the gamma + + align:start position:0% +length of the spindle we call the gamma + + + align:start position:0% +length of the spindle we call the gamma +efferent system + + align:start position:0% +efferent system + + + align:start position:0% +efferent system +coming from gamma motor neurons + + align:start position:0% +coming from gamma motor neurons + + + align:start position:0% +coming from gamma motor neurons +smaller motor neurons in the cord + + align:start position:0% + + + + align:start position:0% + +that shorten the spindle + + align:start position:0% +that shorten the spindle + + + align:start position:0% +that shorten the spindle +which would adjust its sensitivity keep + + align:start position:0% +which would adjust its sensitivity keep + + + align:start position:0% +which would adjust its sensitivity keep +it sensitive to southern stretch + + align:start position:0% +it sensitive to southern stretch + + + align:start position:0% +it sensitive to southern stretch +okay + + align:start position:0% +okay + + + align:start position:0% +okay +now why is that so essential + + align:start position:0% +now why is that so essential + + + align:start position:0% +now why is that so essential +why do we have to keep doing that + + align:start position:0% +why do we have to keep doing that + + + align:start position:0% +why do we have to keep doing that +if you look in any + + align:start position:0% + + + + align:start position:0% + +nerve fiber innervating a muscle okay + + align:start position:0% +nerve fiber innervating a muscle okay + + + align:start position:0% +nerve fiber innervating a muscle okay +you're going to find like 30 percent of + + align:start position:0% +you're going to find like 30 percent of + + + align:start position:0% +you're going to find like 30 percent of +the accents or gamma + + align:start position:0% +the accents or gamma + + + align:start position:0% +the accents or gamma +accents accents from gamma motor neurons + + align:start position:0% +accents accents from gamma motor neurons + + + align:start position:0% +accents accents from gamma motor neurons +much smaller than the axons the alpha + + align:start position:0% +much smaller than the axons the alpha + + + align:start position:0% +much smaller than the axons the alpha +motor neurons okay + + align:start position:0% + + + + align:start position:0% + +well think about it if the spindles are + + align:start position:0% +well think about it if the spindles are + + + align:start position:0% +well think about it if the spindles are +a certain length and they stay that + + align:start position:0% +a certain length and they stay that + + + align:start position:0% +a certain length and they stay that +length then anytime the muscle + + align:start position:0% +length then anytime the muscle + + + align:start position:0% +length then anytime the muscle +stretches out + + align:start position:0% +stretches out + + + align:start position:0% +stretches out +let's say it's at a length so the + + align:start position:0% +let's say it's at a length so the + + + align:start position:0% +let's say it's at a length so the +spindles are + + align:start position:0% +spindles are + + + align:start position:0% +spindles are +firing very little when my arm is in + + align:start position:0% +firing very little when my arm is in + + + align:start position:0% +firing very little when my arm is in +this position and now i + + align:start position:0% +this position and now i + + + align:start position:0% +this position and now i +extend my arm + + align:start position:0% +extend my arm + + + align:start position:0% +extend my arm +i'm lengthening the biceps muscle + + align:start position:0% +i'm lengthening the biceps muscle + + + align:start position:0% +i'm lengthening the biceps muscle +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so the spindle won't fire at all but if + + align:start position:0% +so the spindle won't fire at all but if + + + align:start position:0% +so the spindle won't fire at all but if +i try to make it shorter + + align:start position:0% +i try to make it shorter + + + align:start position:0% +i try to make it shorter +sorry if i lengthen it i'm stretching it + + align:start position:0% +sorry if i lengthen it i'm stretching it + + + align:start position:0% +sorry if i lengthen it i'm stretching it +okay and what will happen the spindles + + align:start position:0% +okay and what will happen the spindles + + + align:start position:0% +okay and what will happen the spindles +organ will cause the afferents to fire + + align:start position:0% +organ will cause the afferents to fire + + + align:start position:0% +organ will cause the afferents to fire +and the muscle will tend to move back to + + align:start position:0% +and the muscle will tend to move back to + + + align:start position:0% +and the muscle will tend to move back to +its position + + align:start position:0% +its position + + + align:start position:0% +its position +tends to keep the muscles in that + + align:start position:0% +tends to keep the muscles in that + + + align:start position:0% +tends to keep the muscles in that +position + + align:start position:0% +position + + + align:start position:0% +position +okay if i shorten it they're not going + + align:start position:0% +okay if i shorten it they're not going + + + align:start position:0% +okay if i shorten it they're not going +to fire if those spindles now don't + + align:start position:0% +to fire if those spindles now don't + + + align:start position:0% +to fire if those spindles now don't +change but on the other hand there's + + align:start position:0% +change but on the other hand there's + + + align:start position:0% +change but on the other hand there's +spindles in the extensor muscle too + + align:start position:0% +spindles in the extensor muscle too + + + align:start position:0% +spindles in the extensor muscle too +so if the spindles are just set + + align:start position:0% +so if the spindles are just set + + + align:start position:0% +so if the spindles are just set +at a certain length the limb will stay + + align:start position:0% +at a certain length the limb will stay + + + align:start position:0% +at a certain length the limb will stay +in one position we'll try to anyway + + align:start position:0% +in one position we'll try to anyway + + + align:start position:0% +in one position we'll try to anyway +because of the muscle to muscle reflex + + align:start position:0% + + + + align:start position:0% + +the afferent from + + align:start position:0% +the afferent from + + + align:start position:0% +the afferent from +the spindle organ + + align:start position:0% +the spindle organ + + + align:start position:0% +the spindle organ +comes in through the dorsal root by a + + align:start position:0% +comes in through the dorsal root by a + + + align:start position:0% +comes in through the dorsal root by a +very large fiber the largest fibers in + + align:start position:0% +very large fiber the largest fibers in + + + align:start position:0% +very large fiber the largest fibers in +the dorsal root the 1a afferents + + align:start position:0% +the dorsal root the 1a afferents + + + align:start position:0% +the dorsal root the 1a afferents +those axons go directly to motor neurons + + align:start position:0% +those axons go directly to motor neurons + + + align:start position:0% +those axons go directly to motor neurons +of the same muscle + + align:start position:0% +of the same muscle + + + align:start position:0% +of the same muscle +okay that's why we call it a muscle to + + align:start position:0% +okay that's why we call it a muscle to + + + align:start position:0% +okay that's why we call it a muscle to +muscle reflex okay + + align:start position:0% +muscle reflex okay + + + align:start position:0% +muscle reflex okay +that responds to muscle stretch so we + + align:start position:0% +that responds to muscle stretch so we + + + align:start position:0% +that responds to muscle stretch so we +also call it the stretch reflex + + align:start position:0% +also call it the stretch reflex + + + align:start position:0% +also call it the stretch reflex +okay + + align:start position:0% +okay + + + align:start position:0% +okay +that is the monosynaptic reflex + + align:start position:0% + + + + align:start position:0% + +and we have to every time we change + + align:start position:0% +and we have to every time we change + + + align:start position:0% +and we have to every time we change +position of the limb we have to change + + align:start position:0% +position of the limb we have to change + + + align:start position:0% +position of the limb we have to change +the length of the spindles + + align:start position:0% +the length of the spindles + + + align:start position:0% +the length of the spindles +in order to keep the spindle sensitive + + align:start position:0% +in order to keep the spindle sensitive + + + align:start position:0% +in order to keep the spindle sensitive +and to allow the muscle to assume any + + align:start position:0% +and to allow the muscle to assume any + + + align:start position:0% +and to allow the muscle to assume any +position that we command it to assume + + align:start position:0% +position that we command it to assume + + + align:start position:0% +position that we command it to assume +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so alpha gamma co-activation is + + align:start position:0% +so alpha gamma co-activation is + + + align:start position:0% +so alpha gamma co-activation is +essential to the functioning of this + + align:start position:0% +essential to the functioning of this + + + align:start position:0% +essential to the functioning of this +system + + align:start position:0% + + + + align:start position:0% + +now i'm thinking about the function of + + align:start position:0% +now i'm thinking about the function of + + + align:start position:0% +now i'm thinking about the function of +the stretch reflex + + align:start position:0% +the stretch reflex + + + align:start position:0% +the stretch reflex +the obvious thing is well it restores + + align:start position:0% +the obvious thing is well it restores + + + align:start position:0% +the obvious thing is well it restores +muscle length + + align:start position:0% +muscle length + + + align:start position:0% +muscle length +let's say i'm i'm holding this and + + align:start position:0% +let's say i'm i'm holding this and + + + align:start position:0% +let's say i'm i'm holding this and +something + + align:start position:0% +something + + + align:start position:0% +something +nudges me and disturbs me + + align:start position:0% +nudges me and disturbs me + + + align:start position:0% +nudges me and disturbs me +right away + + align:start position:0% +right away + + + align:start position:0% +right away +if i'm trying to hold it in one position + + align:start position:0% +if i'm trying to hold it in one position + + + align:start position:0% +if i'm trying to hold it in one position +it'll rise up again because of the + + align:start position:0% +it'll rise up again because of the + + + align:start position:0% +it'll rise up again because of the +muscle muscle i don't even have to think + + align:start position:0% +muscle muscle i don't even have to think + + + align:start position:0% +muscle muscle i don't even have to think +about it okay it will tend to restore + + align:start position:0% +about it okay it will tend to restore + + + align:start position:0% +about it okay it will tend to restore +muscle length + + align:start position:0% +muscle length + + + align:start position:0% +muscle length +it was thought that that must be the + + align:start position:0% +it was thought that that must be the + + + align:start position:0% +it was thought that that must be the +function of the stretch reflex + + align:start position:0% +function of the stretch reflex + + + align:start position:0% +function of the stretch reflex +in fact it thought it was thought that + + align:start position:0% +in fact it thought it was thought that + + + align:start position:0% +in fact it thought it was thought that +well maybe we control our movements that + + align:start position:0% +well maybe we control our movements that + + + align:start position:0% +well maybe we control our movements that +way we just change the spindle settings + + align:start position:0% +way we just change the spindle settings + + + align:start position:0% +way we just change the spindle settings +and then the limb will try to go to the + + align:start position:0% +and then the limb will try to go to the + + + align:start position:0% +and then the limb will try to go to the +corresponding position + + align:start position:0% +corresponding position + + + align:start position:0% +corresponding position +seem like a very good way to + + align:start position:0% +seem like a very good way to + + + align:start position:0% +seem like a very good way to +control + + align:start position:0% +control + + + align:start position:0% +control +the limbs + + align:start position:0% + + + + align:start position:0% + +even with varying amounts of + + align:start position:0% +even with varying amounts of + + + align:start position:0% +even with varying amounts of +resistance + + align:start position:0% +resistance + + + align:start position:0% +resistance +to the movement + + align:start position:0% + + + + align:start position:0% + +but it was found in studies that + + align:start position:0% +but it was found in studies that + + + align:start position:0% +but it was found in studies that +no more than about 30 percent of the + + align:start position:0% +no more than about 30 percent of the + + + align:start position:0% +no more than about 30 percent of the +compensation due to disturbance of the + + align:start position:0% +compensation due to disturbance of the + + + align:start position:0% +compensation due to disturbance of the +limb when it's trying to hold the + + align:start position:0% +limb when it's trying to hold the + + + align:start position:0% +limb when it's trying to hold the +position when you're trying to hold it + + align:start position:0% +position when you're trying to hold it + + + align:start position:0% +position when you're trying to hold it +in one position is due to the stretch + + align:start position:0% +in one position is due to the stretch + + + align:start position:0% +in one position is due to the stretch +reflexes + + align:start position:0% +reflexes + + + align:start position:0% +reflexes +most of it in fact + + align:start position:0% +most of it in fact + + + align:start position:0% +most of it in fact +is due to the spring-like properties of + + align:start position:0% +is due to the spring-like properties of + + + align:start position:0% +is due to the spring-like properties of +muscle you can think of the limb this + + align:start position:0% +muscle you can think of the limb this + + + align:start position:0% +muscle you can think of the limb this +way + + align:start position:0% +way + + + align:start position:0% +way +okay with + + align:start position:0% +okay with + + + align:start position:0% +okay with +if this the green there represents my + + align:start position:0% +if this the green there represents my + + + align:start position:0% +if this the green there represents my +forearm + + align:start position:0% +forearm + + + align:start position:0% +forearm +you can think of the + + align:start position:0% +you can think of the + + + align:start position:0% +you can think of the +of the + + align:start position:0% +of the + + + align:start position:0% +of the +the muscles holding the limb in this + + align:start position:0% +the muscles holding the limb in this + + + align:start position:0% +the muscles holding the limb in this +position like springs connected on + + align:start position:0% +position like springs connected on + + + align:start position:0% +position like springs connected on +either side okay and those springs are + + align:start position:0% +either side okay and those springs are + + + align:start position:0% +either side okay and those springs are +tense + + align:start position:0% +tense + + + align:start position:0% +tense +okay and so if the limb is disturbed + + align:start position:0% +okay and so if the limb is disturbed + + + align:start position:0% +okay and so if the limb is disturbed +okay what happens + + align:start position:0% +okay what happens + + + align:start position:0% +okay what happens +we push that down + + align:start position:0% +we push that down + + + align:start position:0% +we push that down +the spring gets tighter the upper spring + + align:start position:0% +the spring gets tighter the upper spring + + + align:start position:0% +the spring gets tighter the upper spring +this + + align:start position:0% +this + + + align:start position:0% +this +spring gets looser and it will spring + + align:start position:0% +spring gets looser and it will spring + + + align:start position:0% +spring gets looser and it will spring +back + + align:start position:0% +back + + + align:start position:0% +back +that's called the spring-like properties + + align:start position:0% +that's called the spring-like properties + + + align:start position:0% +that's called the spring-like properties +of muscle + + align:start position:0% +of muscle + + + align:start position:0% +of muscle +and a major person in + + align:start position:0% +and a major person in + + + align:start position:0% +and a major person in +specifying the spring-like properties of + + align:start position:0% +specifying the spring-like properties of + + + align:start position:0% +specifying the spring-like properties of +muscles was emilio beat see upstairs + + align:start position:0% + + + + align:start position:0% + +they worked out many of those details + + align:start position:0% +they worked out many of those details + + + align:start position:0% +they worked out many of those details +well the springs have to be have a + + align:start position:0% +well the springs have to be have a + + + align:start position:0% +well the springs have to be have a +certain amount of tension and the + + align:start position:0% +certain amount of tension and the + + + align:start position:0% +certain amount of tension and the +tension + + align:start position:0% +tension + + + align:start position:0% +tension +is what's set + + align:start position:0% +is what's set + + + align:start position:0% +is what's set +by the muscle to muscle reflex + + align:start position:0% +by the muscle to muscle reflex + + + align:start position:0% +by the muscle to muscle reflex +we call that tension muscle stiffness + + align:start position:0% +we call that tension muscle stiffness + + + align:start position:0% +we call that tension muscle stiffness +okay + + align:start position:0% +okay + + + align:start position:0% +okay +muscle stiffness + + align:start position:0% +muscle stiffness + + + align:start position:0% +muscle stiffness +so muscle stiffness is simply how tight + + align:start position:0% +so muscle stiffness is simply how tight + + + align:start position:0% +so muscle stiffness is simply how tight +these springs are + + align:start position:0% +these springs are + + + align:start position:0% +these springs are +how tense the muscles what's the other + + align:start position:0% +how tense the muscles what's the other + + + align:start position:0% +how tense the muscles what's the other +term + + align:start position:0% + + + + align:start position:0% + +we usually talk about muscle tone + + align:start position:0% +we usually talk about muscle tone + + + align:start position:0% +we usually talk about muscle tone +but resting tone is the + + align:start position:0% +but resting tone is the + + + align:start position:0% +but resting tone is the +how tight the muscles are when you're at + + align:start position:0% +how tight the muscles are when you're at + + + align:start position:0% +how tight the muscles are when you're at +rest okay + + align:start position:0% +rest okay + + + align:start position:0% +rest okay +so does that change + + align:start position:0% +so does that change + + + align:start position:0% +so does that change +try something put your arm your hand on + + align:start position:0% +try something put your arm your hand on + + + align:start position:0% +try something put your arm your hand on +your + + align:start position:0% +your + + + align:start position:0% +your +arm so you feel both the biceps and the + + align:start position:0% +arm so you feel both the biceps and the + + + align:start position:0% +arm so you feel both the biceps and the +extensor muscles the triceps on the + + align:start position:0% +extensor muscles the triceps on the + + + align:start position:0% +extensor muscles the triceps on the +other side okay and now you move it in a + + align:start position:0% +other side okay and now you move it in a + + + align:start position:0% +other side okay and now you move it in a +relaxed way + + align:start position:0% +relaxed way + + + align:start position:0% +relaxed way +okay you won't feel the muscles now and + + align:start position:0% +okay you won't feel the muscles now and + + + align:start position:0% +okay you won't feel the muscles now and +now do this speed up the movement and + + align:start position:0% +now do this speed up the movement and + + + align:start position:0% +now do this speed up the movement and +what happens they tighten up on both + + align:start position:0% +what happens they tighten up on both + + + align:start position:0% +what happens they tighten up on both +sides okay whenever you make faster + + align:start position:0% +sides okay whenever you make faster + + + align:start position:0% +sides okay whenever you make faster +movements you get tighter springs + + align:start position:0% +movements you get tighter springs + + + align:start position:0% +movements you get tighter springs +okay now what is that from + + align:start position:0% +okay now what is that from + + + align:start position:0% +okay now what is that from +it's because the gamma efferents are + + align:start position:0% +it's because the gamma efferents are + + + align:start position:0% +it's because the gamma efferents are +firing they tighten up + + align:start position:0% +firing they tighten up + + + align:start position:0% +firing they tighten up +that you get more action of the muscle + + align:start position:0% +that you get more action of the muscle + + + align:start position:0% +that you get more action of the muscle +to muscle reflex + + align:start position:0% +to muscle reflex + + + align:start position:0% +to muscle reflex +okay the muscle spindles are tighter + + align:start position:0% +okay the muscle spindles are tighter + + + align:start position:0% +okay the muscle spindles are tighter +okay getting increased + + align:start position:0% +okay getting increased + + + align:start position:0% +okay getting increased +muscle stiffness or muscle tone + + align:start position:0% +muscle stiffness or muscle tone + + + align:start position:0% +muscle stiffness or muscle tone +very important for fine control of + + align:start position:0% +very important for fine control of + + + align:start position:0% +very important for fine control of +movements + + align:start position:0% +movements + + + align:start position:0% +movements +they have those springs tight + + align:start position:0% +they have those springs tight + + + align:start position:0% +they have those springs tight +and in fact + + align:start position:0% +and in fact + + + align:start position:0% +and in fact +we have good evidence that they're + + align:start position:0% +we have good evidence that they're + + + align:start position:0% +we have good evidence that they're +important in + + align:start position:0% +important in + + + align:start position:0% +important in +fine movement control + + align:start position:0% +fine movement control + + + align:start position:0% +fine movement control +if we look at both phylogenetic + + align:start position:0% +if we look at both phylogenetic + + + align:start position:0% +if we look at both phylogenetic +differences in animals and + + align:start position:0% + + + + align:start position:0% + +for example we look at the iguana + + align:start position:0% +for example we look at the iguana + + + align:start position:0% +for example we look at the iguana +versus the frog i can + + align:start position:0% + + + + align:start position:0% + +if you take a picture here of the spinal + + align:start position:0% +if you take a picture here of the spinal + + + align:start position:0% +if you take a picture here of the spinal +cord + + align:start position:0% + + + + align:start position:0% + +let that be the gray matter on one side + + align:start position:0% +let that be the gray matter on one side + + + align:start position:0% +let that be the gray matter on one side +okay you find the large motor neurons in + + align:start position:0% +okay you find the large motor neurons in + + + align:start position:0% +okay you find the large motor neurons in +these animals that have dendrites that + + align:start position:0% +these animals that have dendrites that + + + align:start position:0% +these animals that have dendrites that +sometimes + + align:start position:0% +sometimes + + + align:start position:0% +sometimes +go way up into the dorsal horn + + align:start position:0% +go way up into the dorsal horn + + + align:start position:0% +go way up into the dorsal horn +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and if you're a + + align:start position:0% +and if you're a + + + align:start position:0% +and if you're a +if you're a frog + + align:start position:0% +if you're a frog + + + align:start position:0% +if you're a frog +these large afferent fibers coming in + + align:start position:0% +these large afferent fibers coming in + + + align:start position:0% +these large afferent fibers coming in +from the dorsal root + + align:start position:0% + + + + align:start position:0% + +some of them will contact the very + + align:start position:0% +some of them will contact the very + + + align:start position:0% +some of them will contact the very +distal parts of those dendrites + + align:start position:0% +distal parts of those dendrites + + + align:start position:0% +distal parts of those dendrites +but if you're an iguana + + align:start position:0% +but if you're an iguana + + + align:start position:0% +but if you're an iguana +we'll make him purple here + + align:start position:0% +we'll make him purple here + + + align:start position:0% +we'll make him purple here +if you're an iguana these contacts are + + align:start position:0% +if you're an iguana these contacts are + + + align:start position:0% +if you're an iguana these contacts are +made much further down the dendrite + + align:start position:0% +made much further down the dendrite + + + align:start position:0% +made much further down the dendrite +getting much tighter + + align:start position:0% +getting much tighter + + + align:start position:0% +getting much tighter +control of the motor neurons by the + + align:start position:0% +control of the motor neurons by the + + + align:start position:0% +control of the motor neurons by the +muscle to muscle reflex + + align:start position:0% + + + + align:start position:0% + +but the other thing and perhaps the + + align:start position:0% +but the other thing and perhaps the + + + align:start position:0% +but the other thing and perhaps the +stronger evidence the iguana by the way + + align:start position:0% +stronger evidence the iguana by the way + + + align:start position:0% +stronger evidence the iguana by the way +is a more advanced lizard + + align:start position:0% +is a more advanced lizard + + + align:start position:0% +is a more advanced lizard +the frog is an amphibian + + align:start position:0% +the frog is an amphibian + + + align:start position:0% +the frog is an amphibian +the iguana has + + align:start position:0% +the iguana has + + + align:start position:0% +the iguana has +much more complex + + align:start position:0% +much more complex + + + align:start position:0% +much more complex +hands and control of his hands than the + + align:start position:0% +hands and control of his hands than the + + + align:start position:0% +hands and control of his hands than the +frog + + align:start position:0% +frog + + + align:start position:0% +frog +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so that's just a correlation but if we + + align:start position:0% +so that's just a correlation but if we + + + align:start position:0% +so that's just a correlation but if we +look at + + align:start position:0% +look at + + + align:start position:0% +look at +the density of muscle spindles okay + + align:start position:0% +the density of muscle spindles okay + + + align:start position:0% +the density of muscle spindles okay +in + + align:start position:0% + + + + align:start position:0% + +various muscles we see that it's much + + align:start position:0% +various muscles we see that it's much + + + align:start position:0% +various muscles we see that it's much +greater in muscles of fine control so + + align:start position:0% +greater in muscles of fine control so + + + align:start position:0% +greater in muscles of fine control so +you have many more spindles in the + + align:start position:0% +you have many more spindles in the + + + align:start position:0% +you have many more spindles in the +muscles of your fingers + + align:start position:0% +muscles of your fingers + + + align:start position:0% +muscles of your fingers +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and your tongue + + align:start position:0% +and your tongue + + + align:start position:0% +and your tongue +than you have in + + align:start position:0% +than you have in + + + align:start position:0% +than you have in +the large muscles of your arm or + + align:start position:0% +the large muscles of your arm or + + + align:start position:0% +the large muscles of your arm or +certainly and you wouldn't have so many + + align:start position:0% +certainly and you wouldn't have so many + + + align:start position:0% +certainly and you wouldn't have so many +of the muscles in the back + + align:start position:0% +of the muscles in the back + + + align:start position:0% +of the muscles in the back +so it's mostly distal muscles + + align:start position:0% + + + + align:start position:0% + +so let's talk a little bit about + + align:start position:0% +so let's talk a little bit about + + + align:start position:0% +so let's talk a little bit about +now spinal cord organization + + align:start position:0% +now spinal cord organization + + + align:start position:0% +now spinal cord organization +remember the name + + align:start position:0% +remember the name + + + align:start position:0% +remember the name +that we give + + align:start position:0% +that we give + + + align:start position:0% +that we give +connections that are formed + + align:start position:0% +connections that are formed + + + align:start position:0% +connections that are formed +within the chord + + align:start position:0% +within the chord + + + align:start position:0% +within the chord +from one part of the chord to another + + align:start position:0% +from one part of the chord to another + + + align:start position:0% +from one part of the chord to another +part of the chord so what we're talking + + align:start position:0% +part of the chord so what we're talking + + + align:start position:0% +part of the chord so what we're talking +about is the function of these + + align:start position:0% +about is the function of these + + + align:start position:0% +about is the function of these +appropriate spinal connections + + align:start position:0% +appropriate spinal connections + + + align:start position:0% +appropriate spinal connections +first of + + align:start position:0% +first of + + + align:start position:0% +first of +all we have action patterns that are + + align:start position:0% +all we have action patterns that are + + + align:start position:0% +all we have action patterns that are +inherited + + align:start position:0% +inherited + + + align:start position:0% +inherited +that are + + align:start position:0% +that are + + + align:start position:0% +that are +formed by connections made all within + + align:start position:0% +formed by connections made all within + + + align:start position:0% +formed by connections made all within +the cord + + align:start position:0% +the cord + + + align:start position:0% +the cord +that when they mature we have these + + align:start position:0% +that when they mature we have these + + + align:start position:0% +that when they mature we have these +these abilities now what what kind of + + align:start position:0% +these abilities now what what kind of + + + align:start position:0% +these abilities now what what kind of +what kind of patterns am i talking about + + align:start position:0% +what kind of patterns am i talking about + + + align:start position:0% +what kind of patterns am i talking about +other than + + align:start position:0% +other than + + + align:start position:0% +other than +other than withdrawal and stretch + + align:start position:0% +other than withdrawal and stretch + + + align:start position:0% +other than withdrawal and stretch +reflexes + + align:start position:0% + + + + align:start position:0% + +well + + align:start position:0% +well + + + align:start position:0% +well +it's been studied by physiologists who + + align:start position:0% +it's been studied by physiologists who + + + align:start position:0% +it's been studied by physiologists who +separate the brain from the spinal cord + + align:start position:0% +separate the brain from the spinal cord + + + align:start position:0% +separate the brain from the spinal cord +and then they maintain it's usually done + + align:start position:0% +and then they maintain it's usually done + + + align:start position:0% +and then they maintain it's usually done +with cats and they maintain them in a + + align:start position:0% +with cats and they maintain them in a + + + align:start position:0% +with cats and they maintain them in a +respirator so they + + align:start position:0% + + + + align:start position:0% + +they keep oxygenating the blood + + align:start position:0% +they keep oxygenating the blood + + + align:start position:0% +they keep oxygenating the blood +and they find that they have alternate + + align:start position:0% +and they find that they have alternate + + + align:start position:0% +and they find that they have alternate +movements of the limbs walking movements + + align:start position:0% +movements of the limbs walking movements + + + align:start position:0% +movements of the limbs walking movements +they find out that they have certain + + align:start position:0% +they find out that they have certain + + + align:start position:0% +they find out that they have certain +reef patterns they call them reflex + + align:start position:0% +reef patterns they call them reflex + + + align:start position:0% +reef patterns they call them reflex +patterns but if one leg hind leg is + + align:start position:0% +patterns but if one leg hind leg is + + + align:start position:0% +patterns but if one leg hind leg is +flexed and the other extended you will + + align:start position:0% +flexed and the other extended you will + + + align:start position:0% +flexed and the other extended you will +get this a similar pattern + + align:start position:0% +get this a similar pattern + + + align:start position:0% +get this a similar pattern +in + + align:start position:0% +in + + + align:start position:0% +in +as if they were walking in the upper + + align:start position:0% +as if they were walking in the upper + + + align:start position:0% +as if they were walking in the upper +limbs okay + + align:start position:0% +limbs okay + + + align:start position:0% +limbs okay +all the basic movements of walking are + + align:start position:0% +all the basic movements of walking are + + + align:start position:0% +all the basic movements of walking are +there and if you + + align:start position:0% +there and if you + + + align:start position:0% +there and if you +put the cap + + align:start position:0% +put the cap + + + align:start position:0% +put the cap +put his hind lips on a treadmill + + align:start position:0% +put his hind lips on a treadmill + + + align:start position:0% +put his hind lips on a treadmill +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and you activate the cord a little bit + + align:start position:0% +and you activate the cord a little bit + + + align:start position:0% +and you activate the cord a little bit +by stimulating the animal + + align:start position:0% +by stimulating the animal + + + align:start position:0% +by stimulating the animal +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and that might be by a descending + + align:start position:0% +and that might be by a descending + + + align:start position:0% +and that might be by a descending +connection that you've spared but there + + align:start position:0% +connection that you've spared but there + + + align:start position:0% +connection that you've spared but there +are other ways to provide input you can + + align:start position:0% +are other ways to provide input you can + + + align:start position:0% +are other ways to provide input you can +stimulate the animal around the anus for + + align:start position:0% +stimulate the animal around the anus for + + + align:start position:0% +stimulate the animal around the anus for +example and it will activate the cord + + align:start position:0% +example and it will activate the cord + + + align:start position:0% +example and it will activate the cord +enough that he will start stepping + + align:start position:0% +enough that he will start stepping + + + align:start position:0% +enough that he will start stepping +and he will walk on the treadmill even + + align:start position:0% +and he will walk on the treadmill even + + + align:start position:0% +and he will walk on the treadmill even +though he's got no connection with the + + align:start position:0% +though he's got no connection with the + + + align:start position:0% +though he's got no connection with the +brain + + align:start position:0% +brain + + + align:start position:0% +brain +so it's got to be spinal the whole thing + + align:start position:0% +so it's got to be spinal the whole thing + + + align:start position:0% +so it's got to be spinal the whole thing +has to be organized in the spinal cord + + align:start position:0% + + + + align:start position:0% + +the scratch reflex is another spinal + + align:start position:0% +the scratch reflex is another spinal + + + align:start position:0% +the scratch reflex is another spinal +reflex we call it that is actually a + + align:start position:0% +reflex we call it that is actually a + + + align:start position:0% +reflex we call it that is actually a +fixed action pattern if we put a + + align:start position:0% +fixed action pattern if we put a + + + align:start position:0% +fixed action pattern if we put a +stimulus say on the back of the cat + + align:start position:0% + + + + align:start position:0% + +he will raise a hind limb in order to + + align:start position:0% +he will raise a hind limb in order to + + + align:start position:0% +he will raise a hind limb in order to +scratch it + + align:start position:0% +scratch it + + + align:start position:0% +scratch it +he will actually scratch and he will + + align:start position:0% +he will actually scratch and he will + + + align:start position:0% +he will actually scratch and he will +show the rhythmic movements of the + + align:start position:0% +show the rhythmic movements of the + + + align:start position:0% +show the rhythmic movements of the +scratching those rhythmic movements and + + align:start position:0% +scratching those rhythmic movements and + + + align:start position:0% +scratching those rhythmic movements and +the positioning of the limb are all + + align:start position:0% +the positioning of the limb are all + + + align:start position:0% +the positioning of the limb are all +controlled by + + align:start position:0% +controlled by + + + align:start position:0% +controlled by +spinal mechanisms + + align:start position:0% + + + + align:start position:0% + +now let's talk about + + align:start position:0% +now let's talk about + + + align:start position:0% +now let's talk about +this + + align:start position:0% +this + + + align:start position:0% +this +spinal modulus of limb movement control + + align:start position:0% +spinal modulus of limb movement control + + + align:start position:0% +spinal modulus of limb movement control +this has to do with how the descending + + align:start position:0% +this has to do with how the descending + + + align:start position:0% +this has to do with how the descending +connections + + align:start position:0% +connections + + + align:start position:0% +connections +control the position of limbs + + align:start position:0% + + + + align:start position:0% + +in the bc lab a few years ago + + align:start position:0% +in the bc lab a few years ago + + + align:start position:0% +in the bc lab a few years ago +they used + + align:start position:0% +they used + + + align:start position:0% +they used +at that time + + align:start position:0% + + + + align:start position:0% + +frogs + + align:start position:0% +frogs + + + align:start position:0% +frogs +all the initial work was done with frogs + + align:start position:0% + + + + align:start position:0% + +they wanted an animal who had a large + + align:start position:0% +they wanted an animal who had a large + + + align:start position:0% +they wanted an animal who had a large +enough cord but also made very simple + + align:start position:0% +enough cord but also made very simple + + + align:start position:0% +enough cord but also made very simple +movements the limbs + + align:start position:0% +movements the limbs + + + align:start position:0% +movements the limbs +it was easy to work with in the + + align:start position:0% +it was easy to work with in the + + + align:start position:0% +it was easy to work with in the +laboratory so they used large bullfrogs + + align:start position:0% +laboratory so they used large bullfrogs + + + align:start position:0% +laboratory so they used large bullfrogs +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and later they verified the work with + + align:start position:0% +and later they verified the work with + + + align:start position:0% +and later they verified the work with +rats large ads + + align:start position:0% +rats large ads + + + align:start position:0% +rats large ads +and i asked you to read a paper on that + + align:start position:0% + + + + align:start position:0% + +basically what they found + + align:start position:0% +basically what they found + + + align:start position:0% +basically what they found +they used this kind of setup okay + + align:start position:0% +they used this kind of setup okay + + + align:start position:0% +they used this kind of setup okay +they had a frog that they had + + align:start position:0% +they had a frog that they had + + + align:start position:0% +they had a frog that they had +clamped in position + + align:start position:0% +clamped in position + + + align:start position:0% +clamped in position +and they put + + align:start position:0% +and they put + + + align:start position:0% +and they put +very tiny electrodes into the spinal + + align:start position:0% +very tiny electrodes into the spinal + + + align:start position:0% +very tiny electrodes into the spinal +cord + + align:start position:0% +cord + + + align:start position:0% +cord +okay + + align:start position:0% + + + + align:start position:0% + +they had one limb hooked up to a force + + align:start position:0% +they had one limb hooked up to a force + + + align:start position:0% +they had one limb hooked up to a force +transducer and they could also measure + + align:start position:0% +transducer and they could also measure + + + align:start position:0% +transducer and they could also measure +tension in the muscles with + + align:start position:0% +tension in the muscles with + + + align:start position:0% +tension in the muscles with +electromyograms + + align:start position:0% +electromyograms + + + align:start position:0% +electromyograms +okay + + align:start position:0% + + + + align:start position:0% + +and + + align:start position:0% + + + + align:start position:0% + +here you see the + + align:start position:0% + + + + align:start position:0% + +the limb + + align:start position:0% +the limb + + + align:start position:0% +the limb +in one position + + align:start position:0% +in one position + + + align:start position:0% +in one position +and then they apply + + align:start position:0% +and then they apply + + + align:start position:0% +and then they apply +the spinal cord + + align:start position:0% +the spinal cord + + + align:start position:0% +the spinal cord +and what they found was when they + + align:start position:0% +and what they found was when they + + + align:start position:0% +and what they found was when they +stimulate certain part of the spinal + + align:start position:0% +stimulate certain part of the spinal + + + align:start position:0% +stimulate certain part of the spinal +cord with this tiny electrode the limb + + align:start position:0% +cord with this tiny electrode the limb + + + align:start position:0% +cord with this tiny electrode the limb +will try to move okay + + align:start position:0% +will try to move okay + + + align:start position:0% +will try to move okay +and what they're depicting in this kind + + align:start position:0% +and what they're depicting in this kind + + + align:start position:0% +and what they're depicting in this kind +of picture + + align:start position:0% +of picture + + + align:start position:0% +of picture +is that if they move + + align:start position:0% + + + + align:start position:0% + +the end of the limb here the + + align:start position:0% +the end of the limb here the + + + align:start position:0% +the end of the limb here the +foot + + align:start position:0% +foot + + + align:start position:0% +foot +into various starting positions and keep + + align:start position:0% +into various starting positions and keep + + + align:start position:0% +into various starting positions and keep +stimulating that same place + + align:start position:0% +stimulating that same place + + + align:start position:0% +stimulating that same place +the limb seems to always move towards + + align:start position:0% +the limb seems to always move towards + + + align:start position:0% +the limb seems to always move towards +a certain position we call that the + + align:start position:0% +a certain position we call that the + + + align:start position:0% +a certain position we call that the +equilibrium point and so if the limb + + align:start position:0% +equilibrium point and so if the limb + + + align:start position:0% +equilibrium point and so if the limb +starts out on that equilibrium point and + + align:start position:0% +starts out on that equilibrium point and + + + align:start position:0% +starts out on that equilibrium point and +you stimulate the cord it will stay + + align:start position:0% +you stimulate the cord it will stay + + + align:start position:0% +you stimulate the cord it will stay +there + + align:start position:0% +there + + + align:start position:0% +there +okay + + align:start position:0% + + + + align:start position:0% + +so it seems to move the limb towards one + + align:start position:0% +so it seems to move the limb towards one + + + align:start position:0% +so it seems to move the limb towards one +position + + align:start position:0% +position + + + align:start position:0% +position +and so they + + align:start position:0% +and so they + + + align:start position:0% +and so they +they + + align:start position:0% +they + + + align:start position:0% +they +created these kinds of pictures vector + + align:start position:0% +created these kinds of pictures vector + + + align:start position:0% +created these kinds of pictures vector +pictures + + align:start position:0% +pictures + + + align:start position:0% +pictures +for + + align:start position:0% +for + + + align:start position:0% +for +various points of stimulation within the + + align:start position:0% +various points of stimulation within the + + + align:start position:0% +various points of stimulation within the +chord and the interesting finding was + + align:start position:0% +chord and the interesting finding was + + + align:start position:0% +chord and the interesting finding was +that even though they stimulated many + + align:start position:0% +that even though they stimulated many + + + align:start position:0% +that even though they stimulated many +many different parts of the gray matter + + align:start position:0% +many different parts of the gray matter + + + align:start position:0% +many different parts of the gray matter +they found only a very limited number of + + align:start position:0% +they found only a very limited number of + + + align:start position:0% +they found only a very limited number of +positions + + align:start position:0% +positions + + + align:start position:0% +positions +in other words many neurons + + align:start position:0% +in other words many neurons + + + align:start position:0% +in other words many neurons +seem to all do the same thing and they + + align:start position:0% +seem to all do the same thing and they + + + align:start position:0% +seem to all do the same thing and they +found that these neurons were + + align:start position:0% +found that these neurons were + + + align:start position:0% +found that these neurons were +distributed in longitudinal columns + + align:start position:0% +distributed in longitudinal columns + + + align:start position:0% +distributed in longitudinal columns +within the core and there were a limited + + align:start position:0% +within the core and there were a limited + + + align:start position:0% +within the core and there were a limited +number of those columns representing + + align:start position:0% +number of those columns representing + + + align:start position:0% +number of those columns representing +a limb + + align:start position:0% +a limb + + + align:start position:0% +a limb +okay + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% + + + + align:start position:0% + +the conclusion was that it sort of + + align:start position:0% +the conclusion was that it sort of + + + align:start position:0% +the conclusion was that it sort of +constitutes a very elementary alphabet + + align:start position:0% +constitutes a very elementary alphabet + + + align:start position:0% +constitutes a very elementary alphabet +for producing complex movements now how + + align:start position:0% +for producing complex movements now how + + + align:start position:0% +for producing complex movements now how +would that be + + align:start position:0% +would that be + + + align:start position:0% +would that be +well they found that if you stimulate + + align:start position:0% +well they found that if you stimulate + + + align:start position:0% +well they found that if you stimulate +more than one + + align:start position:0% +more than one + + + align:start position:0% +more than one +of those columns you sort of get a + + align:start position:0% +of those columns you sort of get a + + + align:start position:0% +of those columns you sort of get a +vector sum + + align:start position:0% +vector sum + + + align:start position:0% +vector sum +of + + align:start position:0% +of + + + align:start position:0% +of +the result of the stimulations done + + align:start position:0% +the result of the stimulations done + + + align:start position:0% +the result of the stimulations done +separately so with the limited number of + + align:start position:0% +separately so with the limited number of + + + align:start position:0% +separately so with the limited number of +columns like that you could get + + align:start position:0% +columns like that you could get + + + align:start position:0% +columns like that you could get +many different kinds of movement + + align:start position:0% +many different kinds of movement + + + align:start position:0% +many different kinds of movement +and move the limb into various positions + + align:start position:0% +and move the limb into various positions + + + align:start position:0% +and move the limb into various positions +now they don't know just they know + + align:start position:0% +now they don't know just they know + + + align:start position:0% +now they don't know just they know +there's not very many + + align:start position:0% +there's not very many + + + align:start position:0% +there's not very many +there's probably more in the rat + + align:start position:0% +there's probably more in the rat + + + align:start position:0% +there's probably more in the rat +and of course they were dealing with + + align:start position:0% +and of course they were dealing with + + + align:start position:0% +and of course they were dealing with +with + + align:start position:0% +with + + + align:start position:0% +with +only one plane of movement so they've + + align:start position:0% +only one plane of movement so they've + + + align:start position:0% +only one plane of movement so they've +simplified the situation quite a bit + + align:start position:0% +simplified the situation quite a bit + + + align:start position:0% +simplified the situation quite a bit +but it's a very basic discovery on how + + align:start position:0% +but it's a very basic discovery on how + + + align:start position:0% +but it's a very basic discovery on how +about spinal organization that + + align:start position:0% +about spinal organization that + + + align:start position:0% +about spinal organization that +simplified the problem of how + + align:start position:0% +simplified the problem of how + + + align:start position:0% +simplified the problem of how +descending connections are controlling + + align:start position:0% +descending connections are controlling + + + align:start position:0% +descending connections are controlling +movement + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +now let's just + + align:start position:0% +now let's just + + + align:start position:0% +now let's just +go + + align:start position:0% +go + + + align:start position:0% +go +a little bit above the + + align:start position:0% +a little bit above the + + + align:start position:0% +a little bit above the +spinal cord the rostral extension of the + + align:start position:0% +spinal cord the rostral extension of the + + + align:start position:0% +spinal cord the rostral extension of the +cord + + align:start position:0% + + + + align:start position:0% + +in latin + + align:start position:0% +in latin + + + align:start position:0% +in latin +the spinal cord is the medulla + + align:start position:0% +the spinal cord is the medulla + + + align:start position:0% +the spinal cord is the medulla +spinalis + + align:start position:0% +spinalis + + + align:start position:0% +spinalis +the spinal marrow + + align:start position:0% +the spinal marrow + + + align:start position:0% +the spinal marrow +the marrow of the spine okay + + align:start position:0% +the marrow of the spine okay + + + align:start position:0% +the marrow of the spine okay +and the oblongation the ex forward + + align:start position:0% +and the oblongation the ex forward + + + align:start position:0% +and the oblongation the ex forward +extension of that is the medulla + + align:start position:0% +extension of that is the medulla + + + align:start position:0% +extension of that is the medulla +oblongata okay so that's the + + align:start position:0% +oblongata okay so that's the + + + align:start position:0% +oblongata okay so that's the +caudal part of the hindbrain + + align:start position:0% +caudal part of the hindbrain + + + align:start position:0% +caudal part of the hindbrain +and when reflexes involve the + + align:start position:0% +and when reflexes involve the + + + align:start position:0% +and when reflexes involve the +medulla oblongata we call them + + align:start position:0% +medulla oblongata we call them + + + align:start position:0% +medulla oblongata we call them +suprasegmental because they're above the + + align:start position:0% +suprasegmental because they're above the + + + align:start position:0% +suprasegmental because they're above the +segment so that they involve connections + + align:start position:0% +segment so that they involve connections + + + align:start position:0% +segment so that they involve connections +above the segments of the cord + + align:start position:0% +above the segments of the cord + + + align:start position:0% +above the segments of the cord +where we have various + + align:start position:0% +where we have various + + + align:start position:0% +where we have various +reflexes controlled autonomic system + + align:start position:0% +reflexes controlled autonomic system + + + align:start position:0% +reflexes controlled autonomic system +reflexes for example controlling blood + + align:start position:0% +reflexes for example controlling blood + + + align:start position:0% +reflexes for example controlling blood +pressure + + align:start position:0% +pressure + + + align:start position:0% +pressure +you say well what reflex controls blood + + align:start position:0% +you say well what reflex controls blood + + + align:start position:0% +you say well what reflex controls blood +pressure + + align:start position:0% +pressure + + + align:start position:0% +pressure +well you have sensory + + align:start position:0% +well you have sensory + + + align:start position:0% +well you have sensory +axons innervating + + align:start position:0% +axons innervating + + + align:start position:0% +axons innervating +special little organs + + align:start position:0% +special little organs + + + align:start position:0% +special little organs +around the branches of the aorta that + + align:start position:0% +around the branches of the aorta that + + + align:start position:0% +around the branches of the aorta that +detect carbon dioxide concentration in + + align:start position:0% +detect carbon dioxide concentration in + + + align:start position:0% +detect carbon dioxide concentration in +the blood so if carbon dioxide goes up + + align:start position:0% +the blood so if carbon dioxide goes up + + + align:start position:0% +the blood so if carbon dioxide goes up +you want to increase hard action + + align:start position:0% +you want to increase hard action + + + align:start position:0% +you want to increase hard action +to get more oxygen + + align:start position:0% +to get more oxygen + + + align:start position:0% +to get more oxygen +okay + + align:start position:0% +okay + + + align:start position:0% +okay +that's the glomerus reflex and that's + + align:start position:0% +that's the glomerus reflex and that's + + + align:start position:0% +that's the glomerus reflex and that's +behind brain reflex + + align:start position:0% +behind brain reflex + + + align:start position:0% +behind brain reflex +and other factor other types of reflexes + + align:start position:0% +and other factor other types of reflexes + + + align:start position:0% +and other factor other types of reflexes +that regulate heartbeat okay + + align:start position:0% +that regulate heartbeat okay + + + align:start position:0% +that regulate heartbeat okay +the heart will beat on its own without + + align:start position:0% +the heart will beat on its own without + + + align:start position:0% +the heart will beat on its own without +that but these hind brain reflexes are + + align:start position:0% +that but these hind brain reflexes are + + + align:start position:0% +that but these hind brain reflexes are +modulating it speeding it up or slowing + + align:start position:0% +modulating it speeding it up or slowing + + + align:start position:0% +modulating it speeding it up or slowing +it down and then we have various + + align:start position:0% +it down and then we have various + + + align:start position:0% +it down and then we have various +protective reflexes + + align:start position:0% + + + + align:start position:0% + +the gag reflex well that's + + align:start position:0% +the gag reflex well that's + + + align:start position:0% +the gag reflex well that's +has to do with swallowing right + + align:start position:0% +has to do with swallowing right + + + align:start position:0% +has to do with swallowing right +i think we triggered that once a few of + + align:start position:0% +i think we triggered that once a few of + + + align:start position:0% +i think we triggered that once a few of +you brave souls did you stuck your hand + + align:start position:0% +you brave souls did you stuck your hand + + + align:start position:0% +you brave souls did you stuck your hand +beyond the circumvent papillion rear of + + align:start position:0% +beyond the circumvent papillion rear of + + + align:start position:0% +beyond the circumvent papillion rear of +your tongue to trigger that reflex gag + + align:start position:0% +your tongue to trigger that reflex gag + + + align:start position:0% +your tongue to trigger that reflex gag +reflex + + align:start position:0% +reflex + + + align:start position:0% +reflex +vomiting is another reflex what normally + + align:start position:0% +vomiting is another reflex what normally + + + align:start position:0% +vomiting is another reflex what normally +triggers vomiting + + align:start position:0% +triggers vomiting + + + align:start position:0% +triggers vomiting +why is it why is it a reflex + + align:start position:0% + + + + align:start position:0% + +well + + align:start position:0% +well + + + align:start position:0% +well +certain toxins + + align:start position:0% +certain toxins + + + align:start position:0% +certain toxins +bad things get into your blood + + align:start position:0% +bad things get into your blood + + + align:start position:0% +bad things get into your blood +from something you've eaten + + align:start position:0% +from something you've eaten + + + align:start position:0% +from something you've eaten +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and it gets into the hindbrain + + align:start position:0% +and it gets into the hindbrain + + + align:start position:0% +and it gets into the hindbrain +to a place in the hindbrain where unlike + + align:start position:0% +to a place in the hindbrain where unlike + + + align:start position:0% +to a place in the hindbrain where unlike +most areas in the brain things from the + + align:start position:0% +most areas in the brain things from the + + + align:start position:0% +most areas in the brain things from the +blood can get in + + align:start position:0% +blood can get in + + + align:start position:0% +blood can get in +right around the area pustrima + + align:start position:0% +right around the area pustrima + + + align:start position:0% +right around the area pustrima +near the obex okay + + align:start position:0% +near the obex okay + + + align:start position:0% +near the obex okay +that + + align:start position:0% +that + + + align:start position:0% +that +caudal end of the + + align:start position:0% +caudal end of the + + + align:start position:0% +caudal end of the +fourth ventricle + + align:start position:0% +fourth ventricle + + + align:start position:0% +fourth ventricle +and you trigger + + align:start position:0% +and you trigger + + + align:start position:0% +and you trigger +that response the vomiting very + + align:start position:0% +that response the vomiting very + + + align:start position:0% +that response the vomiting very +important for + + align:start position:0% +important for + + + align:start position:0% +important for +keeping us alive + + align:start position:0% + + + + align:start position:0% + +reflexes and other mechanisms + + align:start position:0% +reflexes and other mechanisms + + + align:start position:0% +reflexes and other mechanisms +controlling breathing + + align:start position:0% +controlling breathing + + + align:start position:0% +controlling breathing +are also mainly hind brain though they + + align:start position:0% +are also mainly hind brain though they + + + align:start position:0% +are also mainly hind brain though they +involve the caudal midbrain also + + align:start position:0% +involve the caudal midbrain also + + + align:start position:0% +involve the caudal midbrain also +okay and i will talk a little bit about + + align:start position:0% +okay and i will talk a little bit about + + + align:start position:0% +okay and i will talk a little bit about +breathing control + + align:start position:0% + + + + align:start position:0% + +after just after the midterm when we + + align:start position:0% +after just after the midterm when we + + + align:start position:0% +after just after the midterm when we +talk about rhythmic movements + + align:start position:0% + + + + align:start position:0% + +now you have other senses coming into + + align:start position:0% +now you have other senses coming into + + + align:start position:0% +now you have other senses coming into +the time brain too like vestibular sense + + align:start position:0% +the time brain too like vestibular sense + + + align:start position:0% +the time brain too like vestibular sense +auditory sense + + align:start position:0% +auditory sense + + + align:start position:0% +auditory sense +an example of reflexes controlled by + + align:start position:0% +an example of reflexes controlled by + + + align:start position:0% +an example of reflexes controlled by +vestibular sense would be + + align:start position:0% +vestibular sense would be + + + align:start position:0% +vestibular sense would be +the writing reflex + + align:start position:0% +the writing reflex + + + align:start position:0% +the writing reflex +which gets more than just is triggered + + align:start position:0% +which gets more than just is triggered + + + align:start position:0% +which gets more than just is triggered +not only by vestibular input but + + align:start position:0% +not only by vestibular input but + + + align:start position:0% +not only by vestibular input but +semi-sensory input as well + + align:start position:0% + + + + align:start position:0% + +but that's the reflex where if we get + + align:start position:0% +but that's the reflex where if we get + + + align:start position:0% +but that's the reflex where if we get +knocked over we + + align:start position:0% +knocked over we + + + align:start position:0% +knocked over we +tend to ride ourselves it's + + align:start position:0% +tend to ride ourselves it's + + + align:start position:0% +tend to ride ourselves it's +very obvious in an animal like a cat + + align:start position:0% +very obvious in an animal like a cat + + + align:start position:0% +very obvious in an animal like a cat +which will tend to ride itself even in + + align:start position:0% +which will tend to ride itself even in + + + align:start position:0% +which will tend to ride itself even in +the air okay + + align:start position:0% +the air okay + + + align:start position:0% +the air okay +and + + align:start position:0% + + + + align:start position:0% + +if you any animal if you knock him over + + align:start position:0% +if you any animal if you knock him over + + + align:start position:0% +if you any animal if you knock him over +will tend to write himself with a + + align:start position:0% +will tend to write himself with a + + + align:start position:0% +will tend to write himself with a +combination of vestibular and some + + align:start position:0% +combination of vestibular and some + + + align:start position:0% +combination of vestibular and some +sensory reflexes + + align:start position:0% + + + + align:start position:0% + +and then finally + + align:start position:0% +and then finally + + + align:start position:0% +and then finally +subject of your paper many fixed action + + align:start position:0% +subject of your paper many fixed action + + + align:start position:0% +subject of your paper many fixed action +patterns + + align:start position:0% +patterns + + + align:start position:0% +patterns +controlled by hindbrain + + align:start position:0% +controlled by hindbrain + + + align:start position:0% +controlled by hindbrain +at the very simplest level the eye blink + + align:start position:0% +at the very simplest level the eye blink + + + align:start position:0% +at the very simplest level the eye blink +which is more than just a reflex because + + align:start position:0% +which is more than just a reflex because + + + align:start position:0% +which is more than just a reflex because +there's a drive that builds up makes us + + align:start position:0% +there's a drive that builds up makes us + + + align:start position:0% +there's a drive that builds up makes us +want to blink + + align:start position:0% +want to blink + + + align:start position:0% +want to blink +but it's very simple in its connections + + align:start position:0% +but it's very simple in its connections + + + align:start position:0% +but it's very simple in its connections +the swallowing reflex is also really a + + align:start position:0% +the swallowing reflex is also really a + + + align:start position:0% +the swallowing reflex is also really a +fixed action pattern which also has a + + align:start position:0% +fixed action pattern which also has a + + + align:start position:0% +fixed action pattern which also has a +motivational component which builds up + + align:start position:0% +motivational component which builds up + + + align:start position:0% +motivational component which builds up +and involves + + align:start position:0% +and involves + + + align:start position:0% +and involves +over 20 different muscles + + align:start position:0% +over 20 different muscles + + + align:start position:0% +over 20 different muscles +mostly controlled by + + align:start position:0% +mostly controlled by + + + align:start position:0% +mostly controlled by +various levels behind brain and upper + + align:start position:0% +various levels behind brain and upper + + + align:start position:0% +various levels behind brain and upper +even the upper spinal cord + + align:start position:0% + + + + align:start position:0% + +and + + align:start position:0% +and + + + align:start position:0% +and +finally we have many fixed action + + align:start position:0% +finally we have many fixed action + + + align:start position:0% +finally we have many fixed action +patterns involving + + align:start position:0% +patterns involving + + + align:start position:0% +patterns involving +resulting in facial expression + + align:start position:0% +resulting in facial expression + + + align:start position:0% +resulting in facial expression +which also involve control of the tongue + + align:start position:0% +which also involve control of the tongue + + + align:start position:0% +which also involve control of the tongue +as well as + + align:start position:0% +as well as + + + align:start position:0% +as well as +the muscles of the around the lips and + + align:start position:0% +the muscles of the around the lips and + + + align:start position:0% +the muscles of the around the lips and +the whole face + + align:start position:0% +the whole face + + + align:start position:0% +the whole face +okay + + align:start position:0% +okay + + + align:start position:0% +okay +controlled mesial mainly by the facial + + align:start position:0% +controlled mesial mainly by the facial + + + align:start position:0% +controlled mesial mainly by the facial +motor nucleus + + align:start position:0% +motor nucleus + + + align:start position:0% +motor nucleus +and nerve 7. + + align:start position:0% + + + + align:start position:0% + +we're not talking about the input side + + align:start position:0% +we're not talking about the input side + + + align:start position:0% +we're not talking about the input side +since many inputs from the limbic + + align:start position:0% +since many inputs from the limbic + + + align:start position:0% +since many inputs from the limbic +forebrain and visual system control + + align:start position:0% +forebrain and visual system control + + + align:start position:0% +forebrain and visual system control +facial expressions as well we're just + + align:start position:0% +facial expressions as well we're just + + + align:start position:0% +facial expressions as well we're just +talking about the fixed action pattern + + align:start position:0% +talking about the fixed action pattern + + + align:start position:0% +talking about the fixed action pattern +the output side + + align:start position:0% +the output side + + + align:start position:0% +the output side +which is through the hind brain + + align:start position:0% + + + + align:start position:0% + +okay let's talk a little bit about + + align:start position:0% +okay let's talk a little bit about + + + align:start position:0% +okay let's talk a little bit about +plasticity and reflex connections + + align:start position:0% +plasticity and reflex connections + + + align:start position:0% +plasticity and reflex connections +first let me define + + align:start position:0% +first let me define + + + align:start position:0% +first let me define +post titanic potentiation we talked + + align:start position:0% +post titanic potentiation we talked + + + align:start position:0% +post titanic potentiation we talked +about monosynaptic reflexes + + align:start position:0% +about monosynaptic reflexes + + + align:start position:0% +about monosynaptic reflexes +you can enhance + + align:start position:0% +you can enhance + + + align:start position:0% +you can enhance +a monosynaptic reflex in the following + + align:start position:0% +a monosynaptic reflex in the following + + + align:start position:0% +a monosynaptic reflex in the following +way + + align:start position:0% +way + + + align:start position:0% +way +say you first + + align:start position:0% +say you first + + + align:start position:0% +say you first +give a test pulse + + align:start position:0% +give a test pulse + + + align:start position:0% +give a test pulse +to + + align:start position:0% +to + + + align:start position:0% +to +the sensory fibers coming from a muscle + + align:start position:0% +the sensory fibers coming from a muscle + + + align:start position:0% +the sensory fibers coming from a muscle +okay and you will get a twitch of the + + align:start position:0% +okay and you will get a twitch of the + + + align:start position:0% +okay and you will get a twitch of the +muscle + + align:start position:0% +muscle + + + align:start position:0% +muscle +okay + + align:start position:0% +okay + + + align:start position:0% +okay +through the monosynaptic reflex art + + align:start position:0% +through the monosynaptic reflex art + + + align:start position:0% +through the monosynaptic reflex art +we're stimulating input fibers okay so + + align:start position:0% +we're stimulating input fibers okay so + + + align:start position:0% +we're stimulating input fibers okay so +we give a pulse and we'll get a + + align:start position:0% +we give a pulse and we'll get a + + + align:start position:0% +we give a pulse and we'll get a +contraction the muscle okay now we + + align:start position:0% +contraction the muscle okay now we + + + align:start position:0% +contraction the muscle okay now we +stimulate with a tetanus a tetanus means + + align:start position:0% +stimulate with a tetanus a tetanus means + + + align:start position:0% +stimulate with a tetanus a tetanus means +rapid fire + + align:start position:0% +rapid fire + + + align:start position:0% +rapid fire +stimulation + + align:start position:0% +stimulation + + + align:start position:0% +stimulation +you know not just + + align:start position:0% +you know not just + + + align:start position:0% +you know not just +the + + align:start position:0% +the + + + align:start position:0% +the +the + + align:start position:0% +the + + + align:start position:0% +the +dot but + + align:start position:0% +dot but + + + align:start position:0% +dot but +okay you stimulate rapidly that's a + + align:start position:0% +okay you stimulate rapidly that's a + + + align:start position:0% +okay you stimulate rapidly that's a +deadness again if you do that for a + + align:start position:0% +deadness again if you do that for a + + + align:start position:0% +deadness again if you do that for a +little while and now give another single + + align:start position:0% +little while and now give another single + + + align:start position:0% +little while and now give another single +pulse you'll find that you get a greater + + align:start position:0% +pulse you'll find that you get a greater + + + align:start position:0% +pulse you'll find that you get a greater +response than you did before because you + + align:start position:0% +response than you did before because you + + + align:start position:0% +response than you did before because you +have potentiated the monosynaptic reflex + + align:start position:0% +have potentiated the monosynaptic reflex + + + align:start position:0% +have potentiated the monosynaptic reflex +that's post titanic + + align:start position:0% +that's post titanic + + + align:start position:0% +that's post titanic +potentiation + + align:start position:0% + + + + align:start position:0% + +and the much studied long-term + + align:start position:0% +and the much studied long-term + + + align:start position:0% +and the much studied long-term +potentiation here + + align:start position:0% +potentiation here + + + align:start position:0% +potentiation here +of neurons in the central nervous system + + align:start position:0% +of neurons in the central nervous system + + + align:start position:0% +of neurons in the central nervous system +are really a very similar thing + + align:start position:0% +are really a very similar thing + + + align:start position:0% +are really a very similar thing +but not in usually involving such rapid + + align:start position:0% +but not in usually involving such rapid + + + align:start position:0% +but not in usually involving such rapid +stimulation but a potentiation of a + + align:start position:0% +stimulation but a potentiation of a + + + align:start position:0% +stimulation but a potentiation of a +synaptic connection + + align:start position:0% +synaptic connection + + + align:start position:0% +synaptic connection +that lasts a long time is called + + align:start position:0% +that lasts a long time is called + + + align:start position:0% +that lasts a long time is called +long-term potentiation + + align:start position:0% +long-term potentiation + + + align:start position:0% +long-term potentiation +okay now you don't always get + + align:start position:0% +okay now you don't always get + + + align:start position:0% +okay now you don't always get +potentiation by stimulation + + align:start position:0% +potentiation by stimulation + + + align:start position:0% +potentiation by stimulation +okay it happens of course in + + align:start position:0% +okay it happens of course in + + + align:start position:0% +okay it happens of course in +conditioning procedures it happens in + + align:start position:0% +conditioning procedures it happens in + + + align:start position:0% +conditioning procedures it happens in +certain many pathways + + align:start position:0% + + + + align:start position:0% + +if you stimulate at the right rate + + align:start position:0% +if you stimulate at the right rate + + + align:start position:0% +if you stimulate at the right rate +you'll get potentiation but you often if + + align:start position:0% +you'll get potentiation but you often if + + + align:start position:0% +you'll get potentiation but you often if +you get repeated stimulation + + align:start position:0% +you get repeated stimulation + + + align:start position:0% +you get repeated stimulation +you get + + align:start position:0% +you get + + + align:start position:0% +you get +less and less sensitive connections you + + align:start position:0% +less and less sensitive connections you + + + align:start position:0% +less and less sensitive connections you +get habituation + + align:start position:0% +get habituation + + + align:start position:0% +get habituation +so for example + + align:start position:0% +so for example + + + align:start position:0% +so for example +if we have a novel stimulus + + align:start position:0% +if we have a novel stimulus + + + align:start position:0% +if we have a novel stimulus +that causes you to turn your head okay + + align:start position:0% +that causes you to turn your head okay + + + align:start position:0% +that causes you to turn your head okay +you hear a sound that you weren't used + + align:start position:0% +you hear a sound that you weren't used + + + align:start position:0% +you hear a sound that you weren't used +to and you all turned to see what is + + align:start position:0% +to and you all turned to see what is + + + align:start position:0% +to and you all turned to see what is +that you know so you figured out what it + + align:start position:0% +that you know so you figured out what it + + + align:start position:0% +that you know so you figured out what it +is + + align:start position:0% +is + + + align:start position:0% +is +and it elicited a response but what + + align:start position:0% +and it elicited a response but what + + + align:start position:0% +and it elicited a response but what +happens if it keeps up you habituate to + + align:start position:0% +happens if it keeps up you habituate to + + + align:start position:0% +happens if it keeps up you habituate to +it and pretty soon you're totally + + align:start position:0% +it and pretty soon you're totally + + + align:start position:0% +it and pretty soon you're totally +ignoring it you might not even even hear + + align:start position:0% +ignoring it you might not even even hear + + + align:start position:0% +ignoring it you might not even even hear +it anymore if it's an auditory stimulus + + align:start position:0% +it anymore if it's an auditory stimulus + + + align:start position:0% +it anymore if it's an auditory stimulus +and obviously we habituate to the + + align:start position:0% +and obviously we habituate to the + + + align:start position:0% +and obviously we habituate to the +clothes we're wearing we habituate too + + align:start position:0% +clothes we're wearing we habituate too + + + align:start position:0% +clothes we're wearing we habituate too +many stimuli that we just don't pay + + align:start position:0% +many stimuli that we just don't pay + + + align:start position:0% +many stimuli that we just don't pay +attention to anymore + + align:start position:0% +attention to anymore + + + align:start position:0% +attention to anymore +that's a decreased sensitivity well in + + align:start position:0% +that's a decreased sensitivity well in + + + align:start position:0% +that's a decreased sensitivity well in +physiology + + align:start position:0% +physiology + + + align:start position:0% +physiology +they discovered that some of those same + + align:start position:0% +they discovered that some of those same + + + align:start position:0% +they discovered that some of those same +connections that if stimulated at one + + align:start position:0% +connections that if stimulated at one + + + align:start position:0% +connections that if stimulated at one +rate you get potentiation you get + + align:start position:0% +rate you get potentiation you get + + + align:start position:0% +rate you get potentiation you get +long-term potentiation if you stimulate + + align:start position:0% +long-term potentiation if you stimulate + + + align:start position:0% +long-term potentiation if you stimulate +at a much slower rate + + align:start position:0% +at a much slower rate + + + align:start position:0% +at a much slower rate +you'll get reduced sensitivity so they + + align:start position:0% +you'll get reduced sensitivity so they + + + align:start position:0% +you'll get reduced sensitivity so they +call that + + align:start position:0% +call that + + + align:start position:0% +call that +low frequency depression + + align:start position:0% +low frequency depression + + + align:start position:0% +low frequency depression +okay + + align:start position:0% +okay + + + align:start position:0% +okay +these are the physiological phenomena + + align:start position:0% +these are the physiological phenomena + + + align:start position:0% +these are the physiological phenomena +that correspond + + align:start position:0% +that correspond + + + align:start position:0% +that correspond +to the behavioral phenomenon of + + align:start position:0% +to the behavioral phenomenon of + + + align:start position:0% +to the behavioral phenomenon of +habituation or sensitization of reflex + + align:start position:0% + + + + align:start position:0% + +now if we just deal with a spinal cord + + align:start position:0% + + + + align:start position:0% + +can it learn anything + + align:start position:0% +can it learn anything + + + align:start position:0% +can it learn anything +can you get anything besides this post + + align:start position:0% +can you get anything besides this post + + + align:start position:0% +can you get anything besides this post +satanic potentiation + + align:start position:0% +satanic potentiation + + + align:start position:0% +satanic potentiation +okay + + align:start position:0% + + + + align:start position:0% + +so let me describe an experiment that + + align:start position:0% +so let me describe an experiment that + + + align:start position:0% +so let me describe an experiment that +was done that showed that the spinal + + align:start position:0% +was done that showed that the spinal + + + align:start position:0% +was done that showed that the spinal +cord is capable of some learning it was + + align:start position:0% +cord is capable of some learning it was + + + align:start position:0% +cord is capable of some learning it was +based + + align:start position:0% +based + + + align:start position:0% +based +on a simple experiment + + align:start position:0% +on a simple experiment + + + align:start position:0% +on a simple experiment +where they + + align:start position:0% +where they + + + align:start position:0% +where they +took a cockroach + + align:start position:0% +took a cockroach + + + align:start position:0% +took a cockroach +left him attached to the a ganglion + + align:start position:0% +left him attached to the a ganglion + + + align:start position:0% +left him attached to the a ganglion +that's the cockroach's leg and here's a + + align:start position:0% +that's the cockroach's leg and here's a + + + align:start position:0% +that's the cockroach's leg and here's a +beaker of water okay + + align:start position:0% + + + + align:start position:0% + +and here's the water + + align:start position:0% +and here's the water + + + align:start position:0% +and here's the water +and it's conductive we put some salt in + + align:start position:0% +and it's conductive we put some salt in + + + align:start position:0% +and it's conductive we put some salt in +it and it's conductive + + align:start position:0% +it and it's conductive + + + align:start position:0% +it and it's conductive +okay now we we hook that up + + align:start position:0% + + + + align:start position:0% + +we hook it up to a stimulator here okay + + align:start position:0% + + + + align:start position:0% + +we put one probe there + + align:start position:0% +we put one probe there + + + align:start position:0% +we put one probe there +and the other probe will attach to the + + align:start position:0% +and the other probe will attach to the + + + align:start position:0% +and the other probe will attach to the +leg + + align:start position:0% +leg + + + align:start position:0% +leg +okay so what happens we've we've + + align:start position:0% +okay so what happens we've we've + + + align:start position:0% +okay so what happens we've we've +suspended the cockroach leg that way + + align:start position:0% +suspended the cockroach leg that way + + + align:start position:0% +suspended the cockroach leg that way +and you don't even need the cockroach + + align:start position:0% +and you don't even need the cockroach + + + align:start position:0% +and you don't even need the cockroach +there but you do need the ganglion that + + align:start position:0% +there but you do need the ganglion that + + + align:start position:0% +there but you do need the ganglion that +controls it + + align:start position:0% +controls it + + + align:start position:0% +controls it +so you can have part of the cockroach + + align:start position:0% +so you can have part of the cockroach + + + align:start position:0% +so you can have part of the cockroach +the leg in the ganglion okay + + align:start position:0% + + + + align:start position:0% + +so what happens well the leg will extend + + align:start position:0% +so what happens well the leg will extend + + + align:start position:0% +so what happens well the leg will extend +it's not going to stay flexed all the + + align:start position:0% +it's not going to stay flexed all the + + + align:start position:0% +it's not going to stay flexed all the +time it will extend down into the water + + align:start position:0% +time it will extend down into the water + + + align:start position:0% +time it will extend down into the water +and as soon as it touches the water it + + align:start position:0% +and as soon as it touches the water it + + + align:start position:0% +and as soon as it touches the water it +gets a shock + + align:start position:0% +gets a shock + + + align:start position:0% +gets a shock +okay we have it hooked up to a + + align:start position:0% +okay we have it hooked up to a + + + align:start position:0% +okay we have it hooked up to a +stimulator + + align:start position:0% +stimulator + + + align:start position:0% +stimulator +okay so it closes the circuit + + align:start position:0% +okay so it closes the circuit + + + align:start position:0% +okay so it closes the circuit +shocks the leg and you get a withdrawal + + align:start position:0% +shocks the leg and you get a withdrawal + + + align:start position:0% +shocks the leg and you get a withdrawal +reflex + + align:start position:0% +reflex + + + align:start position:0% +reflex +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and then the leg will extend again it + + align:start position:0% +and then the leg will extend again it + + + align:start position:0% +and then the leg will extend again it +will touch the water + + align:start position:0% +will touch the water + + + align:start position:0% +will touch the water +and + + align:start position:0% + + + + align:start position:0% + +well what will happen is that eventually + + align:start position:0% +well what will happen is that eventually + + + align:start position:0% +well what will happen is that eventually +the leg stays up + + align:start position:0% + + + + align:start position:0% + +now if you have another leg and you hook + + align:start position:0% +now if you have another leg and you hook + + + align:start position:0% +now if you have another leg and you hook +it up in series + + align:start position:0% +it up in series + + + align:start position:0% +it up in series +in that circuit + + align:start position:0% +in that circuit + + + align:start position:0% +in that circuit +but it's it's stimulated + + align:start position:0% +but it's it's stimulated + + + align:start position:0% +but it's it's stimulated +in a way that's uncorrelated with the + + align:start position:0% +in a way that's uncorrelated with the + + + align:start position:0% +in a way that's uncorrelated with the +position of the leg + + align:start position:0% +position of the leg + + + align:start position:0% +position of the leg +that leg doesn't learn to stay up + + align:start position:0% +that leg doesn't learn to stay up + + + align:start position:0% +that leg doesn't learn to stay up +it's only where you have this + + align:start position:0% +it's only where you have this + + + align:start position:0% +it's only where you have this +the position of the limb is related to + + align:start position:0% +the position of the limb is related to + + + align:start position:0% +the position of the limb is related to +when the stimulus occurs + + align:start position:0% +when the stimulus occurs + + + align:start position:0% +when the stimulus occurs +that you'll condition it so + + align:start position:0% +that you'll condition it so + + + align:start position:0% +that you'll condition it so +dr charlie gross former mit professor + + align:start position:0% +dr charlie gross former mit professor + + + align:start position:0% +dr charlie gross former mit professor +now it's been for many years now a + + align:start position:0% +now it's been for many years now a + + + align:start position:0% +now it's been for many years now a +professor in the department of + + align:start position:0% +professor in the department of + + + align:start position:0% +professor in the department of +psychology at princeton university + + align:start position:0% +psychology at princeton university + + + align:start position:0% +psychology at princeton university +with his students did + + align:start position:0% +with his students did + + + align:start position:0% +with his students did +a similar experiment on the rat + + align:start position:0% +a similar experiment on the rat + + + align:start position:0% +a similar experiment on the rat +now here they had the whole rat but they + + align:start position:0% +now here they had the whole rat but they + + + align:start position:0% +now here they had the whole rat but they +made him a spinal rat or at least for + + align:start position:0% +made him a spinal rat or at least for + + + align:start position:0% +made him a spinal rat or at least for +the hind limb by doing a mid-thoracic + + align:start position:0% +the hind limb by doing a mid-thoracic + + + align:start position:0% +the hind limb by doing a mid-thoracic +section of the cord okay + + align:start position:0% +section of the cord okay + + + align:start position:0% +section of the cord okay +so now instead of just the cockroach + + align:start position:0% +so now instead of just the cockroach + + + align:start position:0% +so now instead of just the cockroach +they had that was a rat leg + + align:start position:0% +they had that was a rat leg + + + align:start position:0% +they had that was a rat leg +okay + + align:start position:0% +okay + + + align:start position:0% +okay +but they hooked him up the same way they + + align:start position:0% +but they hooked him up the same way they + + + align:start position:0% +but they hooked him up the same way they +were inspired by the cockroach work + + align:start position:0% +were inspired by the cockroach work + + + align:start position:0% +were inspired by the cockroach work +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and again they put another rat in series + + align:start position:0% +and again they put another rat in series + + + align:start position:0% +and again they put another rat in series +okay + + align:start position:0% + + + + align:start position:0% + +so you can imagine how they would do + + align:start position:0% +so you can imagine how they would do + + + align:start position:0% +so you can imagine how they would do +that + + align:start position:0% + + + + align:start position:0% + +they put the other this this hook to + + align:start position:0% +they put the other this this hook to + + + align:start position:0% +they put the other this this hook to +another rad over here okay + + align:start position:0% +another rad over here okay + + + align:start position:0% +another rad over here okay +and there's the rat foot + + align:start position:0% + + + + align:start position:0% + +so now when the if this is the first rod + + align:start position:0% +so now when the if this is the first rod + + + align:start position:0% +so now when the if this is the first rod +over here whenever that rat extends its + + align:start position:0% +over here whenever that rat extends its + + + align:start position:0% +over here whenever that rat extends its +leg + + align:start position:0% +leg + + + align:start position:0% +leg +into the fluid okay both legs get + + align:start position:0% +into the fluid okay both legs get + + + align:start position:0% +into the fluid okay both legs get +stimulated + + align:start position:0% +stimulated + + + align:start position:0% +stimulated +but the leg on the left is only being + + align:start position:0% +but the leg on the left is only being + + + align:start position:0% +but the leg on the left is only being +stimulated when the leg is extending + + align:start position:0% +stimulated when the leg is extending + + + align:start position:0% +stimulated when the leg is extending +into the water the leg on the right is + + align:start position:0% +into the water the leg on the right is + + + align:start position:0% +into the water the leg on the right is +being stimulated at random + + align:start position:0% +being stimulated at random + + + align:start position:0% +being stimulated at random +because it's it's not moving and + + align:start position:0% +because it's it's not moving and + + + align:start position:0% +because it's it's not moving and +synchrony with the other rat it's a + + align:start position:0% +synchrony with the other rat it's a + + + align:start position:0% +synchrony with the other rat it's a +separate rat okay + + align:start position:0% +separate rat okay + + + align:start position:0% +separate rat okay +and what they discovered was the rat + + align:start position:0% +and what they discovered was the rat + + + align:start position:0% +and what they discovered was the rat +with the correlated stimulation gets + + align:start position:0% +with the correlated stimulation gets + + + align:start position:0% +with the correlated stimulation gets +conditioned + + align:start position:0% +conditioned + + + align:start position:0% +conditioned +and the other leg doesn't + + align:start position:0% +and the other leg doesn't + + + align:start position:0% +and the other leg doesn't +you might affect the responses a little + + align:start position:0% +you might affect the responses a little + + + align:start position:0% +you might affect the responses a little +bit of the one on the on the right there + + align:start position:0% +bit of the one on the on the right there + + + align:start position:0% +bit of the one on the on the right there +but + + align:start position:0% + + + + align:start position:0% + +but you don't get the conditioning that + + align:start position:0% +but you don't get the conditioning that + + + align:start position:0% +but you don't get the conditioning that +you do on the left so they got they got + + align:start position:0% +you do on the left so they got they got + + + align:start position:0% +you do on the left so they got they got +some spinal conditioning retention + + align:start position:0% +some spinal conditioning retention + + + align:start position:0% +some spinal conditioning retention +of that learning was not for very long + + align:start position:0% +of that learning was not for very long + + + align:start position:0% +of that learning was not for very long +but + + align:start position:0% +but + + + align:start position:0% +but +it was for many hours okay + + align:start position:0% +it was for many hours okay + + + align:start position:0% +it was for many hours okay +so they did get conditioning in the + + align:start position:0% +so they did get conditioning in the + + + align:start position:0% +so they did get conditioning in the +spinal cord so we know there's some + + align:start position:0% +spinal cord so we know there's some + + + align:start position:0% +spinal cord so we know there's some +simple learning even within the spinal + + align:start position:0% +simple learning even within the spinal + + + align:start position:0% +simple learning even within the spinal +cord + + align:start position:0% +cord + + + align:start position:0% +cord +there's been other experiments on + + align:start position:0% +there's been other experiments on + + + align:start position:0% +there's been other experiments on +spinal control and one favorite one that + + align:start position:0% +spinal control and one favorite one that + + + align:start position:0% +spinal control and one favorite one that +i like was done with crossing of nerves + + align:start position:0% +i like was done with crossing of nerves + + + align:start position:0% +i like was done with crossing of nerves +they took + + align:start position:0% +they took + + + align:start position:0% +they took +this is the last thing we'll talk about + + align:start position:0% +this is the last thing we'll talk about + + + align:start position:0% +this is the last thing we'll talk about +today + + align:start position:0% +today + + + align:start position:0% +today +sorry + + align:start position:0% + + + + align:start position:0% + +if you take + + align:start position:0% +if you take + + + align:start position:0% +if you take +the nerves to the + + align:start position:0% +the nerves to the + + + align:start position:0% +the nerves to the +foot + + align:start position:0% +foot + + + align:start position:0% +foot +and you + + align:start position:0% +and you + + + align:start position:0% +and you +sever the extensors and the flexors + + align:start position:0% +sever the extensors and the flexors + + + align:start position:0% +sever the extensors and the flexors +cross them over and get them to + + align:start position:0% +cross them over and get them to + + + align:start position:0% +cross them over and get them to +regenerate to the wrong muscles so now + + align:start position:0% +regenerate to the wrong muscles so now + + + align:start position:0% +regenerate to the wrong muscles so now +the the nerve that would innervate + + align:start position:0% +the the nerve that would innervate + + + align:start position:0% +the the nerve that would innervate +flexors is now stimulating the extensors + + align:start position:0% +flexors is now stimulating the extensors + + + align:start position:0% +flexors is now stimulating the extensors +it regenerates into the extensor muscles + + align:start position:0% +it regenerates into the extensor muscles + + + align:start position:0% +it regenerates into the extensor muscles +okay so now when that when they + + align:start position:0% +okay so now when that when they + + + align:start position:0% +okay so now when that when they +regenerate if you've done that to a rat + + align:start position:0% +regenerate if you've done that to a rat + + + align:start position:0% +regenerate if you've done that to a rat +every time the rat wants to raise his + + align:start position:0% +every time the rat wants to raise his + + + align:start position:0% +every time the rat wants to raise his +foot he lowers it and when he wants to + + align:start position:0% +foot he lowers it and when he wants to + + + align:start position:0% +foot he lowers it and when he wants to +lower it he raises it + + align:start position:0% +lower it he raises it + + + align:start position:0% +lower it he raises it +and they've done that with monkeys and + + align:start position:0% +and they've done that with monkeys and + + + align:start position:0% +and they've done that with monkeys and +cats and rats + + align:start position:0% +cats and rats + + + align:start position:0% +cats and rats +now what happens + + align:start position:0% +now what happens + + + align:start position:0% +now what happens +over time of course all the feedback is + + align:start position:0% +over time of course all the feedback is + + + align:start position:0% +over time of course all the feedback is +wrong + + align:start position:0% +wrong + + + align:start position:0% +wrong +so do they learn + + align:start position:0% + + + + align:start position:0% + +rats learn almost nothing + + align:start position:0% +rats learn almost nothing + + + align:start position:0% +rats learn almost nothing +they keep they maintain their + + align:start position:0% +they keep they maintain their + + + align:start position:0% +they keep they maintain their +uncoordinated movements because the + + align:start position:0% +uncoordinated movements because the + + + align:start position:0% +uncoordinated movements because the +spinal cord is not adapting to the + + align:start position:0% +spinal cord is not adapting to the + + + align:start position:0% +spinal cord is not adapting to the +abnormal feedback + + align:start position:0% +abnormal feedback + + + align:start position:0% +abnormal feedback +it's not learning + + align:start position:0% + + + + align:start position:0% + +but in the monkey they found that over + + align:start position:0% +but in the monkey they found that over + + + align:start position:0% +but in the monkey they found that over +time the monkey learns to coordinate + + align:start position:0% +time the monkey learns to coordinate + + + align:start position:0% +time the monkey learns to coordinate +islam again + + align:start position:0% +islam again + + + align:start position:0% +islam again +okay does that mean the monkey spinal + + align:start position:0% +okay does that mean the monkey spinal + + + align:start position:0% +okay does that mean the monkey spinal +cord is more plastic than the rat spinal + + align:start position:0% +cord is more plastic than the rat spinal + + + align:start position:0% +cord is more plastic than the rat spinal +cord well not necessarily because these + + align:start position:0% +cord well not necessarily because these + + + align:start position:0% +cord well not necessarily because these +are not spinal animals + + align:start position:0% +are not spinal animals + + + align:start position:0% +are not spinal animals +so they tried then severing descending + + align:start position:0% +so they tried then severing descending + + + align:start position:0% +so they tried then severing descending +connections + + align:start position:0% +connections + + + align:start position:0% +connections +in those monkeys and they found that as + + align:start position:0% +in those monkeys and they found that as + + + align:start position:0% +in those monkeys and they found that as +soon as the descending connections were + + align:start position:0% +soon as the descending connections were + + + align:start position:0% +soon as the descending connections were +severed the monkey becomes like the rat + + align:start position:0% +severed the monkey becomes like the rat + + + align:start position:0% +severed the monkey becomes like the rat +he shows the reverse all the adaptation + + align:start position:0% +he shows the reverse all the adaptation + + + align:start position:0% +he shows the reverse all the adaptation +all the learning had taken place above + + align:start position:0% +all the learning had taken place above + + + align:start position:0% +all the learning had taken place above +the level of the spinal cord okay so the + + align:start position:0% +the level of the spinal cord okay so the + + + align:start position:0% +the level of the spinal cord okay so the +even though we can get some simple + + align:start position:0% +even though we can get some simple + + + align:start position:0% +even though we can get some simple +conditioning at the level of spinal cord + + align:start position:0% +conditioning at the level of spinal cord + + + align:start position:0% +conditioning at the level of spinal cord +it doesn't extend to this kind of + + align:start position:0% +it doesn't extend to this kind of + + + align:start position:0% +it doesn't extend to this kind of +adaptation an adaptation to such a + + align:start position:0% +adaptation an adaptation to such a + + + align:start position:0% +adaptation an adaptation to such a +mis-wiring of the connections okay + + align:start position:0% +mis-wiring of the connections okay + + + align:start position:0% +mis-wiring of the connections okay +all right + + align:start position:0% +all right + + + align:start position:0% +all right +next time we were going to talk about + + align:start position:0% +next time we were going to talk about + + + align:start position:0% +next time we were going to talk about +the higher systems the role of + + align:start position:0% +the higher systems the role of + + + align:start position:0% +the higher systems the role of +descending pathways we'll describe the + + align:start position:0% +descending pathways we'll describe the + + + align:start position:0% +descending pathways we'll describe the +anatomy and then we'll see a film of a + + align:start position:0% +anatomy and then we'll see a film of a + + + align:start position:0% +anatomy and then we'll see a film of a +famous experiment on monkeys \ No newline at end of file diff --git a/945Cm4obJ5o.txt b/945Cm4obJ5o.txt new file mode 100644 index 0000000000000000000000000000000000000000..8db202e08de24bdb4162f53f31bae3f5addfae01 --- /dev/null +++ b/945Cm4obJ5o.txt @@ -0,0 +1,8435 @@ +align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +now we've discussed motor system at + + align:start position:0% +now we've discussed motor system at + + + align:start position:0% +now we've discussed motor system at +spinal level a few basic things + + align:start position:0% +spinal level a few basic things + + + align:start position:0% +spinal level a few basic things +dealing with spinal reflexes + + align:start position:0% + + + + align:start position:0% + +applies also to hindbrain + + align:start position:0% + + + + align:start position:0% + +the first + + align:start position:0% + + + + align:start position:0% + +a first wash at the motor looking at + + align:start position:0% +a first wash at the motor looking at + + + align:start position:0% +a first wash at the motor looking at +higher control is just to continue + + align:start position:0% +higher control is just to continue + + + align:start position:0% +higher control is just to continue +using the reflex model + + align:start position:0% +using the reflex model + + + align:start position:0% +using the reflex model +and speak of motor control in terms of a + + align:start position:0% +and speak of motor control in terms of a + + + align:start position:0% +and speak of motor control in terms of a +hierarchy of reflexes + + align:start position:0% +hierarchy of reflexes + + + align:start position:0% +hierarchy of reflexes +in other words you + + align:start position:0% + + + + align:start position:0% + +you have reflexes involving various + + align:start position:0% +you have reflexes involving various + + + align:start position:0% +you have reflexes involving various +length of password pathways reaching + + align:start position:0% +length of password pathways reaching + + + align:start position:0% +length of password pathways reaching +finally the neocortex + + align:start position:0% +finally the neocortex + + + align:start position:0% +finally the neocortex +the idea is that + + align:start position:0% +the idea is that + + + align:start position:0% +the idea is that +information from this one of the somatic + + align:start position:0% +information from this one of the somatic + + + align:start position:0% +information from this one of the somatic +systems + + align:start position:0% +systems + + + align:start position:0% +systems +reaches a primary sensory area of + + align:start position:0% +reaches a primary sensory area of + + + align:start position:0% +reaches a primary sensory area of +neocortex + + align:start position:0% +neocortex + + + align:start position:0% +neocortex +and from there it goes to association + + align:start position:0% +and from there it goes to association + + + align:start position:0% +and from there it goes to association +areas and from there it finally will + + align:start position:0% +areas and from there it finally will + + + align:start position:0% +areas and from there it finally will +reach + + align:start position:0% +reach + + + align:start position:0% +reach +motor cortex + + align:start position:0% +motor cortex + + + align:start position:0% +motor cortex +and that way influence movement + + align:start position:0% + + + + align:start position:0% + +and + + align:start position:0% +and + + + align:start position:0% +and +first of all + + align:start position:0% + + + + align:start position:0% + +information does follow such pathways + + align:start position:0% +information does follow such pathways + + + align:start position:0% +information does follow such pathways +okay + + align:start position:0% +okay + + + align:start position:0% +okay +anatomical studies and physiological + + align:start position:0% +anatomical studies and physiological + + + align:start position:0% +anatomical studies and physiological +studies that demonstrate that + + align:start position:0% +studies that demonstrate that + + + align:start position:0% +studies that demonstrate that +there are such pathways + + align:start position:0% +there are such pathways + + + align:start position:0% +there are such pathways +so isn't that been + + align:start position:0% +so isn't that been + + + align:start position:0% +so isn't that been +the adequate way to think about it + + align:start position:0% +the adequate way to think about it + + + align:start position:0% +the adequate way to think about it +and you'll see it written that about it + + align:start position:0% +and you'll see it written that about it + + + align:start position:0% +and you'll see it written that about it +this way in textbooks and so forth + + align:start position:0% +this way in textbooks and so forth + + + align:start position:0% +this way in textbooks and so forth +but there's a number of problems with it + + align:start position:0% +but there's a number of problems with it + + + align:start position:0% +but there's a number of problems with it +one is that is an adequate theory + + align:start position:0% +one is that is an adequate theory + + + align:start position:0% +one is that is an adequate theory +because one is that neocortical areas + + align:start position:0% +because one is that neocortical areas + + + align:start position:0% +because one is that neocortical areas +have many outputs other than these + + align:start position:0% +have many outputs other than these + + + align:start position:0% +have many outputs other than these +transcortical pathways that reach the + + align:start position:0% +transcortical pathways that reach the + + + align:start position:0% +transcortical pathways that reach the +motor cortex + + align:start position:0% +motor cortex + + + align:start position:0% +motor cortex +they can control movements + + align:start position:0% +they can control movements + + + align:start position:0% +they can control movements +without any motor cortex + + align:start position:0% +without any motor cortex + + + align:start position:0% +without any motor cortex +okay + + align:start position:0% + + + + align:start position:0% + +for example visual cortex + + align:start position:0% +for example visual cortex + + + align:start position:0% +for example visual cortex +doesn't just project + + align:start position:0% +doesn't just project + + + align:start position:0% +doesn't just project +the + + align:start position:0% +the + + + align:start position:0% +the +areas adjacent to it and then + + align:start position:0% +areas adjacent to it and then + + + align:start position:0% +areas adjacent to it and then +and there are some very nice + + align:start position:0% +and there are some very nice + + + align:start position:0% +and there are some very nice +transcriptable pathways and they are + + align:start position:0% +transcriptable pathways and they are + + + align:start position:0% +transcriptable pathways and they are +made of major importance in our vision + + align:start position:0% +made of major importance in our vision + + + align:start position:0% +made of major importance in our vision +but it also projects directly to + + align:start position:0% +but it also projects directly to + + + align:start position:0% +but it also projects directly to +subcortical systems it projects to the + + align:start position:0% +subcortical systems it projects to the + + + align:start position:0% +subcortical systems it projects to the +tectum for example as do other visual + + align:start position:0% +tectum for example as do other visual + + + align:start position:0% +tectum for example as do other visual +areas okay + + align:start position:0% +areas okay + + + align:start position:0% +areas okay +and they can affect movement directly + + align:start position:0% +and they can affect movement directly + + + align:start position:0% +and they can affect movement directly +through their pathway to the midbrain + + align:start position:0% +through their pathway to the midbrain + + + align:start position:0% +through their pathway to the midbrain +without going to motor cortex + + align:start position:0% +without going to motor cortex + + + align:start position:0% +without going to motor cortex +and also we have this + + align:start position:0% +and also we have this + + + align:start position:0% +and also we have this +issue of endogenous control you can have + + align:start position:0% +issue of endogenous control you can have + + + align:start position:0% +issue of endogenous control you can have +movement that originates from activity + + align:start position:0% +movement that originates from activity + + + align:start position:0% +movement that originates from activity +generated within the nervous system not + + align:start position:0% +generated within the nervous system not + + + align:start position:0% +generated within the nervous system not +involving specific inputs + + align:start position:0% + + + + align:start position:0% + +now in clinical neurology + + align:start position:0% +now in clinical neurology + + + align:start position:0% +now in clinical neurology +frequently + + align:start position:0% +frequently + + + align:start position:0% +frequently +a chapter on the motor system + + align:start position:0% +a chapter on the motor system + + + align:start position:0% +a chapter on the motor system +will begin by defining the pyramidal + + align:start position:0% +will begin by defining the pyramidal + + + align:start position:0% +will begin by defining the pyramidal +system and extra grammar systems + + align:start position:0% +system and extra grammar systems + + + align:start position:0% +system and extra grammar systems +and in fact + + align:start position:0% + + + + align:start position:0% + +a view that you will still still + + align:start position:0% +a view that you will still still + + + align:start position:0% +a view that you will still still +sometimes see + + align:start position:0% +sometimes see + + + align:start position:0% +sometimes see +taught is that the pyramidal system is + + align:start position:0% +taught is that the pyramidal system is + + + align:start position:0% +taught is that the pyramidal system is +our system for voluntary motor control + + align:start position:0% +our system for voluntary motor control + + + align:start position:0% +our system for voluntary motor control +extra parameter system for involuntary + + align:start position:0% +extra parameter system for involuntary + + + align:start position:0% +extra parameter system for involuntary +movement + + align:start position:0% +movement + + + align:start position:0% +movement +you will see in the film that that is + + align:start position:0% +you will see in the film that that is + + + align:start position:0% +you will see in the film that that is +very very unlikely but you don't have + + align:start position:0% +very very unlikely but you don't have + + + align:start position:0% +very very unlikely but you don't have +this if the film is about monkey work + + align:start position:0% +this if the film is about monkey work + + + align:start position:0% +this if the film is about monkey work +even with human work you can have people + + align:start position:0% +even with human work you can have people + + + align:start position:0% +even with human work you can have people +that have had sections of pyramidal + + align:start position:0% +that have had sections of pyramidal + + + align:start position:0% +that have had sections of pyramidal +track + + align:start position:0% +track + + + align:start position:0% +track +they lack the pramble system for motor + + align:start position:0% +they lack the pramble system for motor + + + align:start position:0% +they lack the pramble system for motor +control and yet + + align:start position:0% +control and yet + + + align:start position:0% +control and yet +they certainly have voluntary movement + + align:start position:0% +they certainly have voluntary movement + + + align:start position:0% +they certainly have voluntary movement +it may not be completely normal + + align:start position:0% +it may not be completely normal + + + align:start position:0% +it may not be completely normal +they have motor defects + + align:start position:0% +they have motor defects + + + align:start position:0% +they have motor defects +and we'll see that for the monkeys in + + align:start position:0% +and we'll see that for the monkeys in + + + align:start position:0% +and we'll see that for the monkeys in +the film + + align:start position:0% +the film + + + align:start position:0% +the film +okay but it's this initial consideration + + align:start position:0% +okay but it's this initial consideration + + + align:start position:0% +okay but it's this initial consideration +that it has to do with + + align:start position:0% +that it has to do with + + + align:start position:0% +that it has to do with +voluntary and involuntary is certainly + + align:start position:0% +voluntary and involuntary is certainly + + + align:start position:0% +voluntary and involuntary is certainly +not the case + + align:start position:0% +not the case + + + align:start position:0% +not the case +but their anatomical considerations that + + align:start position:0% +but their anatomical considerations that + + + align:start position:0% +but their anatomical considerations that +also show that this is unlikely + + align:start position:0% +also show that this is unlikely + + + align:start position:0% +also show that this is unlikely +at least some of the major + + align:start position:0% +at least some of the major + + + align:start position:0% +at least some of the major +extrapyramidal systems the two major + + align:start position:0% +extrapyramidal systems the two major + + + align:start position:0% +extrapyramidal systems the two major +ones usually discussed in medical school + + align:start position:0% +ones usually discussed in medical school + + + align:start position:0% +ones usually discussed in medical school +textbooks are the cerebellar system and + + align:start position:0% +textbooks are the cerebellar system and + + + align:start position:0% +textbooks are the cerebellar system and +corpus + + align:start position:0% +corpus + + + align:start position:0% +corpus +triada in fact their major outputs in + + align:start position:0% +triada in fact their major outputs in + + + align:start position:0% +triada in fact their major outputs in +higher mammals + + align:start position:0% +higher mammals + + + align:start position:0% +higher mammals +is to the pyramidal system + + align:start position:0% +is to the pyramidal system + + + align:start position:0% +is to the pyramidal system +and i pointed out here how that works + + align:start position:0% +and i pointed out here how that works + + + align:start position:0% +and i pointed out here how that works +cerebellum projects to these more + + align:start position:0% +cerebellum projects to these more + + + align:start position:0% +cerebellum projects to these more +anterior parts of the ventral nucleus of + + align:start position:0% +anterior parts of the ventral nucleus of + + + align:start position:0% +anterior parts of the ventral nucleus of +the thalamus the vl in the va + + align:start position:0% +the thalamus the vl in the va + + + align:start position:0% +the thalamus the vl in the va +cerebellum goes + + align:start position:0% +cerebellum goes + + + align:start position:0% +cerebellum goes +mainly to vl + + align:start position:0% + + + + align:start position:0% + +which then projects to motor cortex + + align:start position:0% +which then projects to motor cortex + + + align:start position:0% +which then projects to motor cortex +sorry did i + + align:start position:0% +sorry did i + + + align:start position:0% +sorry did i +not reading what i'm writing here + + align:start position:0% + + + + align:start position:0% + +cerebellum goes mainly to vl copies + + align:start position:0% +cerebellum goes mainly to vl copies + + + align:start position:0% +cerebellum goes mainly to vl copies +triadon to va okay but they both project + + align:start position:0% +triadon to va okay but they both project + + + align:start position:0% +triadon to va okay but they both project +to both those areas and they go to the + + align:start position:0% +to both those areas and they go to the + + + align:start position:0% +to both those areas and they go to the +motor cortex okay + + align:start position:0% +motor cortex okay + + + align:start position:0% +motor cortex okay +and which then is the major contributor + + align:start position:0% +and which then is the major contributor + + + align:start position:0% +and which then is the major contributor +at least forty percent of the pyramidal + + align:start position:0% +at least forty percent of the pyramidal + + + align:start position:0% +at least forty percent of the pyramidal +track comes from the motor cortex + + align:start position:0% + + + + align:start position:0% + +and these neocortical areas even the + + align:start position:0% +and these neocortical areas even the + + + align:start position:0% +and these neocortical areas even the +motor cortex have many other projections + + align:start position:0% +motor cortex have many other projections + + + align:start position:0% +motor cortex have many other projections +other than to the pyramidal tract + + align:start position:0% + + + + align:start position:0% + +for example + + align:start position:0% +for example + + + align:start position:0% +for example +almost the entire neocortex projects to + + align:start position:0% +almost the entire neocortex projects to + + + align:start position:0% +almost the entire neocortex projects to +the corpus triatum which has outputs + + align:start position:0% +the corpus triatum which has outputs + + + align:start position:0% +the corpus triatum which has outputs +separate + + align:start position:0% +separate + + + align:start position:0% +separate +from those that go back to the thalamus + + align:start position:0% +from those that go back to the thalamus + + + align:start position:0% +from those that go back to the thalamus +and motor cortex so + + align:start position:0% + + + + align:start position:0% + +the way we're going to do this is we're + + align:start position:0% +the way we're going to do this is we're + + + align:start position:0% +the way we're going to do this is we're +going to follow lawrence and kuipers and + + align:start position:0% +going to follow lawrence and kuipers and + + + align:start position:0% +going to follow lawrence and kuipers and +their classic work which was began with + + align:start position:0% +their classic work which was began with + + + align:start position:0% +their classic work which was began with +neuroanatomical studies of descending + + align:start position:0% +neuroanatomical studies of descending + + + align:start position:0% +neuroanatomical studies of descending +pathways + + align:start position:0% +pathways + + + align:start position:0% +pathways +and the organization of spinal cord + + align:start position:0% +and the organization of spinal cord + + + align:start position:0% +and the organization of spinal cord +motor neurons + + align:start position:0% +motor neurons + + + align:start position:0% +motor neurons +okay + + align:start position:0% + + + + align:start position:0% + +so we'll look at the spinal cord at one + + align:start position:0% +so we'll look at the spinal cord at one + + + align:start position:0% +so we'll look at the spinal cord at one +of the enlargements + + align:start position:0% +of the enlargements + + + align:start position:0% +of the enlargements +and + + align:start position:0% +and + + + align:start position:0% +and +the organization of motor neurons and + + align:start position:0% +the organization of motor neurons and + + + align:start position:0% +the organization of motor neurons and +then we'll talk about how the higher + + align:start position:0% +then we'll talk about how the higher + + + align:start position:0% +then we'll talk about how the higher +systems project to that + + align:start position:0% + + + + align:start position:0% + +so these are their two pictures + + align:start position:0% +so these are their two pictures + + + align:start position:0% +so these are their two pictures +i have an enlargement of this one okay + + align:start position:0% +i have an enlargement of this one okay + + + align:start position:0% +i have an enlargement of this one okay +so i want you to understand what this is + + align:start position:0% +so i want you to understand what this is + + + align:start position:0% +so i want you to understand what this is +showing + + align:start position:0% + + + + align:start position:0% + +at the top there you have these are all + + align:start position:0% +at the top there you have these are all + + + align:start position:0% +at the top there you have these are all +cross sections of the spinal cord at the + + align:start position:0% +cross sections of the spinal cord at the + + + align:start position:0% +cross sections of the spinal cord at the +lumbar enlargement okay controlling the + + align:start position:0% +lumbar enlargement okay controlling the + + + align:start position:0% +lumbar enlargement okay controlling the +lower limb muscles okay + + align:start position:0% +lower limb muscles okay + + + align:start position:0% +lower limb muscles okay +so first look at the bottom here + + align:start position:0% +so first look at the bottom here + + + align:start position:0% +so first look at the bottom here +they're showing motor neurons + + align:start position:0% +they're showing motor neurons + + + align:start position:0% +they're showing motor neurons +they're located + + align:start position:0% +they're located + + + align:start position:0% +they're located +all across from medial + + align:start position:0% +all across from medial + + + align:start position:0% +all across from medial +to lateral here + + align:start position:0% +to lateral here + + + align:start position:0% +to lateral here +we'll call this dorsolateral here we'll + + align:start position:0% +we'll call this dorsolateral here we'll + + + align:start position:0% +we'll call this dorsolateral here we'll +just call it lateral + + align:start position:0% +just call it lateral + + + align:start position:0% +just call it lateral +this is ventromedial we'll call it + + align:start position:0% +this is ventromedial we'll call it + + + align:start position:0% +this is ventromedial we'll call it +medial okay + + align:start position:0% +medial okay + + + align:start position:0% +medial okay +now those motor neurons are arranged + + align:start position:0% +now those motor neurons are arranged + + + align:start position:0% +now those motor neurons are arranged +in an orderly way so that the most + + align:start position:0% +in an orderly way so that the most + + + align:start position:0% +in an orderly way so that the most +distal muscles are represented laterally + + align:start position:0% +distal muscles are represented laterally + + + align:start position:0% +distal muscles are represented laterally +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so if you wanted to find a neuron + + align:start position:0% +so if you wanted to find a neuron + + + align:start position:0% +so if you wanted to find a neuron +controlling the toe + + align:start position:0% +controlling the toe + + + align:start position:0% +controlling the toe +you would look way out here + + align:start position:0% +you would look way out here + + + align:start position:0% +you would look way out here +if you wanted to find a motor neuron + + align:start position:0% +if you wanted to find a motor neuron + + + align:start position:0% +if you wanted to find a motor neuron +controlling + + align:start position:0% +controlling + + + align:start position:0% +controlling +say the muscles along the back + + align:start position:0% +say the muscles along the back + + + align:start position:0% +say the muscles along the back +you would look + + align:start position:0% +you would look + + + align:start position:0% +you would look +in the most medial area okay here + + align:start position:0% + + + + align:start position:0% + +and in between you would find motor + + align:start position:0% +and in between you would find motor + + + align:start position:0% +and in between you would find motor +neurons controlling the hip + + align:start position:0% +neurons controlling the hip + + + align:start position:0% +neurons controlling the hip +okay similarly now for the + + align:start position:0% +okay similarly now for the + + + align:start position:0% +okay similarly now for the +cervical enlargement + + align:start position:0% +cervical enlargement + + + align:start position:0% +cervical enlargement +the lateral motor neurons would be + + align:start position:0% +the lateral motor neurons would be + + + align:start position:0% +the lateral motor neurons would be +controlling our fingers + + align:start position:0% +controlling our fingers + + + align:start position:0% +controlling our fingers +and then + + align:start position:0% +and then + + + align:start position:0% +and then +the arms as you move medially + + align:start position:0% +the arms as you move medially + + + align:start position:0% +the arms as you move medially +and then the girdle muscles the shoulder + + align:start position:0% +and then the girdle muscles the shoulder + + + align:start position:0% +and then the girdle muscles the shoulder +and then most immediately the axial + + align:start position:0% +and then most immediately the axial + + + align:start position:0% +and then most immediately the axial +muscle + + align:start position:0% +muscle + + + align:start position:0% +muscle +keeping us upright controlling our + + align:start position:0% +keeping us upright controlling our + + + align:start position:0% +keeping us upright controlling our +balance and posture + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so what connects to those well first of + + align:start position:0% +so what connects to those well first of + + + align:start position:0% +so what connects to those well first of +all the interneuronal pool + + align:start position:0% +all the interneuronal pool + + + align:start position:0% +all the interneuronal pool +of neurons that are not motor neurons + + align:start position:0% +of neurons that are not motor neurons + + + align:start position:0% +of neurons that are not motor neurons +but they connect to motor neurons they + + align:start position:0% +but they connect to motor neurons they + + + align:start position:0% +but they connect to motor neurons they +also connect in an orderly way so the + + align:start position:0% +also connect in an orderly way so the + + + align:start position:0% +also connect in an orderly way so the +lateral or dorsolateral part here + + align:start position:0% +lateral or dorsolateral part here + + + align:start position:0% +lateral or dorsolateral part here +connect the lateral motor neurons the + + align:start position:0% +connect the lateral motor neurons the + + + align:start position:0% +connect the lateral motor neurons the +medial ones connect the medial there's + + align:start position:0% +medial ones connect the medial there's + + + align:start position:0% +medial ones connect the medial there's +one other point about that the medial + + align:start position:0% +one other point about that the medial + + + align:start position:0% +one other point about that the medial +interneurons tend to have axons that go + + align:start position:0% +interneurons tend to have axons that go + + + align:start position:0% +interneurons tend to have axons that go +to both sides + + align:start position:0% +to both sides + + + align:start position:0% +to both sides +but not the lateral ones okay + + align:start position:0% +but not the lateral ones okay + + + align:start position:0% +but not the lateral ones okay +and that will see + + align:start position:0% +and that will see + + + align:start position:0% +and that will see +a consistent pattern here that those + + align:start position:0% +a consistent pattern here that those + + + align:start position:0% +a consistent pattern here that those +medial ones tend to be more bilateral in + + align:start position:0% +medial ones tend to be more bilateral in + + + align:start position:0% +medial ones tend to be more bilateral in +their connections + + align:start position:0% +their connections + + + align:start position:0% +their connections +and we'll see that's because they're + + align:start position:0% +and we'll see that's because they're + + + align:start position:0% +and we'll see that's because they're +controlling whole body movements + + align:start position:0% +controlling whole body movements + + + align:start position:0% +controlling whole body movements +movements of large part of the body + + align:start position:0% +movements of large part of the body + + + align:start position:0% +movements of large part of the body +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so then the next step for lawrence and + + align:start position:0% +so then the next step for lawrence and + + + align:start position:0% +so then the next step for lawrence and +kuipers was to say okay what projects to + + align:start position:0% +kuipers was to say okay what projects to + + + align:start position:0% +kuipers was to say okay what projects to +those interneurons + + align:start position:0% +those interneurons + + + align:start position:0% +those interneurons +they knew that major contributors were + + align:start position:0% +they knew that major contributors were + + + align:start position:0% +they knew that major contributors were +coming from the brain so they looked at + + align:start position:0% +coming from the brain so they looked at + + + align:start position:0% +coming from the brain so they looked at +the corticospinal tract and they saw + + align:start position:0% +the corticospinal tract and they saw + + + align:start position:0% +the corticospinal tract and they saw +these were degeneration studies they're + + align:start position:0% +these were degeneration studies they're + + + align:start position:0% +these were degeneration studies they're +looking at the pattern of projections + + align:start position:0% +looking at the pattern of projections + + + align:start position:0% +looking at the pattern of projections +shown by degenerating axons after legion + + align:start position:0% +shown by degenerating axons after legion + + + align:start position:0% +shown by degenerating axons after legion +of motor cortex or a section of the + + align:start position:0% +of motor cortex or a section of the + + + align:start position:0% +of motor cortex or a section of the +parameter and they see that it goes to + + align:start position:0% +parameter and they see that it goes to + + + align:start position:0% +parameter and they see that it goes to +the whole thing here + + align:start position:0% +the whole thing here + + + align:start position:0% +the whole thing here +it goes laterally it goes medially and a + + align:start position:0% +it goes laterally it goes medially and a + + + align:start position:0% +it goes laterally it goes medially and a +little bit to the other side but when it + + align:start position:0% +little bit to the other side but when it + + + align:start position:0% +little bit to the other side but when it +goes to the other side it goes only to + + align:start position:0% +goes to the other side it goes only to + + + align:start position:0% +goes to the other side it goes only to +that ventral medial area almost entirely + + align:start position:0% +that ventral medial area almost entirely + + + align:start position:0% +that ventral medial area almost entirely +okay so now + + align:start position:0% +okay so now + + + align:start position:0% +okay so now +other than the pyramidal tract + + align:start position:0% +other than the pyramidal tract + + + align:start position:0% +other than the pyramidal tract +where the other descending connections + + align:start position:0% +where the other descending connections + + + align:start position:0% +where the other descending connections +that come from the brainstem go + + align:start position:0% +that come from the brainstem go + + + align:start position:0% +that come from the brainstem go +they saw that they were nicely divided + + align:start position:0% +they saw that they were nicely divided + + + align:start position:0% +they saw that they were nicely divided +into two types of connections + + align:start position:0% +into two types of connections + + + align:start position:0% +into two types of connections +the red nucleus the rubric spinal tract + + align:start position:0% +the red nucleus the rubric spinal tract + + + align:start position:0% +the red nucleus the rubric spinal tract +connects to the more lateral internal + + align:start position:0% +connects to the more lateral internal + + + align:start position:0% +connects to the more lateral internal +pool + + align:start position:0% +pool + + + align:start position:0% +pool +connecting then to the left which then + + align:start position:0% +connecting then to the left which then + + + align:start position:0% +connecting then to the left which then +would be influencing the lateral motor + + align:start position:0% +would be influencing the lateral motor + + + align:start position:0% +would be influencing the lateral motor +neurons so and that fits functional + + align:start position:0% +neurons so and that fits functional + + + align:start position:0% +neurons so and that fits functional +studies that show that the red nucleus + + align:start position:0% +studies that show that the red nucleus + + + align:start position:0% +studies that show that the red nucleus +is particularly important in limb + + align:start position:0% +is particularly important in limb + + + align:start position:0% +is particularly important in limb +control + + align:start position:0% +control + + + align:start position:0% +control +limb and hand control okay + + align:start position:0% + + + + align:start position:0% + +whereas the pathways that follow + + align:start position:0% +whereas the pathways that follow + + + align:start position:0% +whereas the pathways that follow +the + + align:start position:0% +the + + + align:start position:0% +the +that come from the ventromedial hind + + align:start position:0% +that come from the ventromedial hind + + + align:start position:0% +that come from the ventromedial hind +brain + + align:start position:0% +brain + + + align:start position:0% +brain +and they tend to travel + + align:start position:0% +and they tend to travel + + + align:start position:0% +and they tend to travel +in the ventral and these ventral columns + + align:start position:0% +in the ventral and these ventral columns + + + align:start position:0% +in the ventral and these ventral columns +of the core the ventral + + align:start position:0% +of the core the ventral + + + align:start position:0% +of the core the ventral +funiculus okay + + align:start position:0% +funiculus okay + + + align:start position:0% +funiculus okay +they project to that ventral medial area + + align:start position:0% +they project to that ventral medial area + + + align:start position:0% +they project to that ventral medial area +controlling axial muscles + + align:start position:0% +controlling axial muscles + + + align:start position:0% +controlling axial muscles +and again axons coming here down the + + align:start position:0% +and again axons coming here down the + + + align:start position:0% +and again axons coming here down the +left side will also tend to cross over + + align:start position:0% +left side will also tend to cross over + + + align:start position:0% +left side will also tend to cross over +and go to the other side + + align:start position:0% +and go to the other side + + + align:start position:0% +and go to the other side +now what are those pathways + + align:start position:0% +now what are those pathways + + + align:start position:0% +now what are those pathways +vestibulospinal + + align:start position:0% + + + + align:start position:0% + +tactile spinal + + align:start position:0% + + + + align:start position:0% + +cerebellospinal the vestigial spinal + + align:start position:0% +cerebellospinal the vestigial spinal + + + align:start position:0% +cerebellospinal the vestigial spinal +sometimes we call it because it comes + + align:start position:0% +sometimes we call it because it comes + + + align:start position:0% +sometimes we call it because it comes +from the this digital nucleus the most + + align:start position:0% +from the this digital nucleus the most + + + align:start position:0% +from the this digital nucleus the most +medial nucleus in the cerebellum okay + + align:start position:0% +medial nucleus in the cerebellum okay + + + align:start position:0% +medial nucleus in the cerebellum okay +and also from the medial reticular + + align:start position:0% +and also from the medial reticular + + + align:start position:0% +and also from the medial reticular +formation large neurons in the reticular + + align:start position:0% +formation large neurons in the reticular + + + align:start position:0% +formation large neurons in the reticular +formation which we know are concerned + + align:start position:0% +formation which we know are concerned + + + align:start position:0% +formation which we know are concerned +with + + align:start position:0% +with + + + align:start position:0% +with +various fixed action patterns and so + + align:start position:0% +various fixed action patterns and so + + + align:start position:0% +various fixed action patterns and so +forth controlled often often concerned + + align:start position:0% +forth controlled often often concerned + + + align:start position:0% +forth controlled often often concerned +with whole body movements + + align:start position:0% +with whole body movements + + + align:start position:0% +with whole body movements +okay + + align:start position:0% +okay + + + align:start position:0% +okay +i just list them there for you + + align:start position:0% +i just list them there for you + + + align:start position:0% +i just list them there for you +so now + + align:start position:0% + + + + align:start position:0% + +this just shows the same pathways + + align:start position:0% +this just shows the same pathways + + + align:start position:0% +this just shows the same pathways +instead of on a cross section here i put + + align:start position:0% +instead of on a cross section here i put + + + align:start position:0% +instead of on a cross section here i put +them on a picture of the monkey brain + + align:start position:0% +them on a picture of the monkey brain + + + align:start position:0% +them on a picture of the monkey brain +and i show here the motor cortex + + align:start position:0% +and i show here the motor cortex + + + align:start position:0% +and i show here the motor cortex +with the areas representing the distal + + align:start position:0% +with the areas representing the distal + + + align:start position:0% +with the areas representing the distal +muscles + + align:start position:0% +muscles + + + align:start position:0% +muscles +in the dark lines and then i also show + + align:start position:0% +in the dark lines and then i also show + + + align:start position:0% +in the dark lines and then i also show +the the other they i show that both + + align:start position:0% +the the other they i show that both + + + align:start position:0% +the the other they i show that both +systems are going throughout the cord + + align:start position:0% +systems are going throughout the cord + + + align:start position:0% +systems are going throughout the cord +if you're just looking at motor neurons + + align:start position:0% +if you're just looking at motor neurons + + + align:start position:0% +if you're just looking at motor neurons +representing hands they would go to the + + align:start position:0% +representing hands they would go to the + + + align:start position:0% +representing hands they would go to the +upper enlargement the feet the lower + + align:start position:0% +upper enlargement the feet the lower + + + align:start position:0% +upper enlargement the feet the lower +enlargement + + align:start position:0% +enlargement + + + align:start position:0% +enlargement +but + + align:start position:0% +but + + + align:start position:0% +but +basically the neocortex goes to all + + align:start position:0% +basically the neocortex goes to all + + + align:start position:0% +basically the neocortex goes to all +levels and all parts + + align:start position:0% +levels and all parts + + + align:start position:0% +levels and all parts +of that system medial and lateral + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +now if we go + + align:start position:0% +now if we go + + + align:start position:0% +now if we go +here's the red nucleus and i show its + + align:start position:0% +here's the red nucleus and i show its + + + align:start position:0% +here's the red nucleus and i show its +cross projection here you see where it + + align:start position:0% +cross projection here you see where it + + + align:start position:0% +cross projection here you see where it +travels laterally in the hindbrain and + + align:start position:0% +travels laterally in the hindbrain and + + + align:start position:0% +travels laterally in the hindbrain and +here it's on the longitudinal view it's + + align:start position:0% +here it's on the longitudinal view it's + + + align:start position:0% +here it's on the longitudinal view it's +crossing over it projects to the lateral + + align:start position:0% +crossing over it projects to the lateral + + + align:start position:0% +crossing over it projects to the lateral +hind brain and then it projects mainly + + align:start position:0% +hind brain and then it projects mainly + + + align:start position:0% +hind brain and then it projects mainly +laterally in the core of the + + align:start position:0% +laterally in the core of the + + + align:start position:0% +laterally in the core of the +enlargements + + align:start position:0% +enlargements + + + align:start position:0% +enlargements +the medial pathways + + align:start position:0% +the medial pathways + + + align:start position:0% +the medial pathways +travel medially in the cord and they + + align:start position:0% +travel medially in the cord and they + + + align:start position:0% +travel medially in the cord and they +tend to distribute bilaterally here they + + align:start position:0% +tend to distribute bilaterally here they + + + align:start position:0% +tend to distribute bilaterally here they +are going through the hindbrain + + align:start position:0% +are going through the hindbrain + + + align:start position:0% +are going through the hindbrain +here's the origin of the tectospinal + + align:start position:0% +here's the origin of the tectospinal + + + align:start position:0% +here's the origin of the tectospinal +tract + + align:start position:0% +tract + + + align:start position:0% +tract +here i'm showing the way that the + + align:start position:0% +here i'm showing the way that the + + + align:start position:0% +here i'm showing the way that the +stimulospinal tract originates okay + + align:start position:0% +stimulospinal tract originates okay + + + align:start position:0% +stimulospinal tract originates okay +descends + + align:start position:0% +descends + + + align:start position:0% +descends +to all levels of the chord now not just + + align:start position:0% +to all levels of the chord now not just + + + align:start position:0% +to all levels of the chord now not just +the enlargements but all levels okay and + + align:start position:0% +the enlargements but all levels okay and + + + align:start position:0% +the enlargements but all levels okay and +tends to terminate in that medial part + + align:start position:0% +tends to terminate in that medial part + + + align:start position:0% +tends to terminate in that medial part +of the chord + + align:start position:0% +of the chord + + + align:start position:0% +of the chord +okay + + align:start position:0% +okay + + + align:start position:0% +okay +this is just to show you that my + + align:start position:0% +this is just to show you that my + + + align:start position:0% +this is just to show you that my +pictures are a lot better than appears + + align:start position:0% +pictures are a lot better than appears + + + align:start position:0% +pictures are a lot better than appears +in the textbooks + + align:start position:0% +in the textbooks + + + align:start position:0% +in the textbooks +i these are very difficult to understand + + align:start position:0% +i these are very difficult to understand + + + align:start position:0% +i these are very difficult to understand +if you study it for a while you might be + + align:start position:0% +if you study it for a while you might be + + + align:start position:0% +if you study it for a while you might be +able to make it out and relate it to + + align:start position:0% +able to make it out and relate it to + + + align:start position:0% +able to make it out and relate it to +what i've shown you + + align:start position:0% +what i've shown you + + + align:start position:0% +what i've shown you +showing here the corticospinal tract + + align:start position:0% +showing here the corticospinal tract + + + align:start position:0% +showing here the corticospinal tract +traveling laterally here + + align:start position:0% +traveling laterally here + + + align:start position:0% +traveling laterally here +the lateral funiculus of the cord and + + align:start position:0% +the lateral funiculus of the cord and + + + align:start position:0% +the lateral funiculus of the cord and +trying to depict various levels + + align:start position:0% +trying to depict various levels + + + align:start position:0% +trying to depict various levels +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so now let's we're going to look at this + + align:start position:0% +so now let's we're going to look at this + + + align:start position:0% +so now let's we're going to look at this +film and this is what we're going to see + + align:start position:0% +film and this is what we're going to see + + + align:start position:0% +film and this is what we're going to see +first + + align:start position:0% +first + + + align:start position:0% +first +they did paramedotomies they section the + + align:start position:0% +they did paramedotomies they section the + + + align:start position:0% +they did paramedotomies they section the +pyramidal track + + align:start position:0% +pyramidal track + + + align:start position:0% +pyramidal track +okay + + align:start position:0% + + + + align:start position:0% + +here's the first lesion on that + + align:start position:0% +here's the first lesion on that + + + align:start position:0% +here's the first lesion on that +anatomical diagram they cut the primal + + align:start position:0% +anatomical diagram they cut the primal + + + align:start position:0% +anatomical diagram they cut the primal +tract here in the hindbrain so here in + + align:start position:0% +tract here in the hindbrain so here in + + + align:start position:0% +tract here in the hindbrain so here in +this picture that's where they cut it + + align:start position:0% +this picture that's where they cut it + + + align:start position:0% +this picture that's where they cut it +they cut it bilaterally + + align:start position:0% +they cut it bilaterally + + + align:start position:0% +they cut it bilaterally +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so we'll see a monkey then with no + + align:start position:0% +so we'll see a monkey then with no + + + align:start position:0% +so we'll see a monkey then with no +paranormal track and we'll see he has a + + align:start position:0% +paranormal track and we'll see he has a + + + align:start position:0% +paranormal track and we'll see he has a +lot of voluntary movement we'll see what + + align:start position:0% +lot of voluntary movement we'll see what + + + align:start position:0% +lot of voluntary movement we'll see what +he lacks he doesn't have single digit + + align:start position:0% +he lacks he doesn't have single digit + + + align:start position:0% +he lacks he doesn't have single digit +control he loses some + + align:start position:0% +control he loses some + + + align:start position:0% +control he loses some +he loses some manual dexterity also + + align:start position:0% +he loses some manual dexterity also + + + align:start position:0% +he loses some manual dexterity also +loses speed + + align:start position:0% +loses speed + + + align:start position:0% +loses speed +okay then lesion two + + align:start position:0% +okay then lesion two + + + align:start position:0% +okay then lesion two +they made a bilateral cut + + align:start position:0% +they made a bilateral cut + + + align:start position:0% +they made a bilateral cut +in the hind brain sectioning all those + + align:start position:0% +in the hind brain sectioning all those + + + align:start position:0% +in the hind brain sectioning all those +medial pathways they're going right + + align:start position:0% +medial pathways they're going right + + + align:start position:0% +medial pathways they're going right +there through the primal track but + + align:start position:0% +there through the primal track but + + + align:start position:0% +there through the primal track but +that's already degenerating and we'll + + align:start position:0% +that's already degenerating and we'll + + + align:start position:0% +that's already degenerating and we'll +see the histological sections + + align:start position:0% +see the histological sections + + + align:start position:0% +see the histological sections +demonstrating that okay + + align:start position:0% +demonstrating that okay + + + align:start position:0% +demonstrating that okay +and i'll explain that when we see it so + + align:start position:0% +and i'll explain that when we see it so + + + align:start position:0% +and i'll explain that when we see it so +here on this view there's where they're + + align:start position:0% +here on this view there's where they're + + + align:start position:0% +here on this view there's where they're +cutting it + + align:start position:0% +cutting it + + + align:start position:0% +cutting it +they if they do that lesion you know i + + align:start position:0% +they if they do that lesion you know i + + + align:start position:0% +they if they do that lesion you know i +believe they didn't get much effect but + + align:start position:0% +believe they didn't get much effect but + + + align:start position:0% +believe they didn't get much effect but +remember that system tends to be + + align:start position:0% +remember that system tends to be + + + align:start position:0% +remember that system tends to be +bilateral in its connections so you + + align:start position:0% +bilateral in its connections so you + + + align:start position:0% +bilateral in its connections so you +really have to cut it on both sides the + + align:start position:0% +really have to cut it on both sides the + + + align:start position:0% +really have to cut it on both sides the +most impaired monkey you'll see in the + + align:start position:0% +most impaired monkey you'll see in the + + + align:start position:0% +most impaired monkey you'll see in the +film is one with that + + align:start position:0% +film is one with that + + + align:start position:0% +film is one with that +the pyramidal track lesion first and + + align:start position:0% +the pyramidal track lesion first and + + + align:start position:0% +the pyramidal track lesion first and +then this + + align:start position:0% +then this + + + align:start position:0% +then this +the medial hindbrain + + align:start position:0% +the medial hindbrain + + + align:start position:0% +the medial hindbrain +pathways section + + align:start position:0% +pathways section + + + align:start position:0% +pathways section +because he can't write himself not for + + align:start position:0% +because he can't write himself not for + + + align:start position:0% +because he can't write himself not for +40 days anyway he finally + + align:start position:0% +40 days anyway he finally + + + align:start position:0% +40 days anyway he finally +recovers enough that the sensory control + + align:start position:0% +recovers enough that the sensory control + + + align:start position:0% +recovers enough that the sensory control +of writing + + align:start position:0% +of writing + + + align:start position:0% +of writing +that he can write himself again he lacks + + align:start position:0% +that he can write himself again he lacks + + + align:start position:0% +that he can write himself again he lacks +those vestibular pathways okay + + align:start position:0% +those vestibular pathways okay + + + align:start position:0% +those vestibular pathways okay +and then finally + + align:start position:0% + + + + align:start position:0% + +in some of the parameterized monkeys + + align:start position:0% +in some of the parameterized monkeys + + + align:start position:0% +in some of the parameterized monkeys +they tried just doing the lateral + + align:start position:0% +they tried just doing the lateral + + + align:start position:0% +they tried just doing the lateral +pathways but only on one side and then + + align:start position:0% +pathways but only on one side and then + + + align:start position:0% +pathways but only on one side and then +we'll compare the two hands + + align:start position:0% +we'll compare the two hands + + + align:start position:0% +we'll compare the two hands +okay and you'll see + + align:start position:0% +okay and you'll see + + + align:start position:0% +okay and you'll see +how they affect the limp the hand + + align:start position:0% +how they affect the limp the hand + + + align:start position:0% +how they affect the limp the hand +movements now are mainly under control + + align:start position:0% +movements now are mainly under control + + + align:start position:0% +movements now are mainly under control +of that system + + align:start position:0% + + + + align:start position:0% + +okay so + + align:start position:0% +okay so + + + align:start position:0% +okay so +could you hit that button and see if we + + align:start position:0% +could you hit that button and see if we + + + align:start position:0% +could you hit that button and see if we +can get the video + + align:start position:0% + + + + align:start position:0% + +oh good + + align:start position:0% +oh good + + + align:start position:0% +oh good +okay so first just a normal animal and + + align:start position:0% +okay so first just a normal animal and + + + align:start position:0% +okay so first just a normal animal and +you'll see how they're testing him + + align:start position:0% +you'll see how they're testing him + + + align:start position:0% +you'll see how they're testing him +they have him strapped to the chair so + + align:start position:0% +they have him strapped to the chair so + + + align:start position:0% +they have him strapped to the chair so +he can't run around and they're + + align:start position:0% +he can't run around and they're + + + align:start position:0% +he can't run around and they're +presenting little pieces of apple here + + align:start position:0% +presenting little pieces of apple here + + + align:start position:0% +presenting little pieces of apple here +you see the normal animal + + align:start position:0% +you see the normal animal + + + align:start position:0% +you see the normal animal +very dexterous moves very fast + + align:start position:0% +very dexterous moves very fast + + + align:start position:0% +very dexterous moves very fast +can grab + + align:start position:0% +can grab + + + align:start position:0% +can grab +just about as well as we could + + align:start position:0% +just about as well as we could + + + align:start position:0% +just about as well as we could +the pieces of apple + + align:start position:0% + + + + align:start position:0% + +and on this little board they make the + + align:start position:0% +and on this little board they make the + + + align:start position:0% +and on this little board they make the +holes smaller and smaller so he has to + + align:start position:0% +holes smaller and smaller so he has to + + + align:start position:0% +holes smaller and smaller so he has to +be more dexterous to get the + + align:start position:0% +be more dexterous to get the + + + align:start position:0% +be more dexterous to get the +apple out of the tiny holes and when he + + align:start position:0% +apple out of the tiny holes and when he + + + align:start position:0% +apple out of the tiny holes and when he +gets so excited he has a little problem + + align:start position:0% +gets so excited he has a little problem + + + align:start position:0% +gets so excited he has a little problem +but he can do it + + align:start position:0% + + + + align:start position:0% + +monkeys have hands similar to ours + + align:start position:0% +monkeys have hands similar to ours + + + align:start position:0% +monkeys have hands similar to ours +they're very dexterous okay they also + + align:start position:0% +they're very dexterous okay they also + + + align:start position:0% +they're very dexterous okay they also +have the opposing thumb + + align:start position:0% +have the opposing thumb + + + align:start position:0% +have the opposing thumb +although not nearly as good as ours + + align:start position:0% + + + + align:start position:0% + +in order to prevent the animal from + + align:start position:0% +in order to prevent the animal from + + + align:start position:0% +in order to prevent the animal from +using both hands they often have to hold + + align:start position:0% +using both hands they often have to hold + + + align:start position:0% +using both hands they often have to hold +or hold one hand down + + align:start position:0% +or hold one hand down + + + align:start position:0% +or hold one hand down +okay + + align:start position:0% + + + + align:start position:0% + +they + + align:start position:0% +they + + + align:start position:0% +they +monkeys that just get their dry food + + align:start position:0% +monkeys that just get their dry food + + + align:start position:0% +monkeys that just get their dry food +will always want this fruit + + align:start position:0% +will always want this fruit + + + align:start position:0% +will always want this fruit +okay so you don't have to deprive them + + align:start position:0% +okay so you don't have to deprive them + + + align:start position:0% +okay so you don't have to deprive them +much to do this + + align:start position:0% + + + + align:start position:0% + +like hamsters with + + align:start position:0% +like hamsters with + + + align:start position:0% +like hamsters with +hamsters with sunflower seeds okay + + align:start position:0% +hamsters with sunflower seeds okay + + + align:start position:0% +hamsters with sunflower seeds okay +so now in these little holes he can't + + align:start position:0% +so now in these little holes he can't + + + align:start position:0% +so now in these little holes he can't +get it out unless he can use one digit + + align:start position:0% +get it out unless he can use one digit + + + align:start position:0% +get it out unless he can use one digit +he has to have some independent control + + align:start position:0% +he has to have some independent control + + + align:start position:0% +he has to have some independent control +of the one digit that's what they're + + align:start position:0% +of the one digit that's what they're + + + align:start position:0% +of the one digit that's what they're +showing here + + align:start position:0% +showing here + + + align:start position:0% +showing here +just like a person + + align:start position:0% +just like a person + + + align:start position:0% +just like a person +just like a person they're pretty good + + align:start position:0% +just like a person they're pretty good + + + align:start position:0% +just like a person they're pretty good +at that okay + + align:start position:0% + + + + align:start position:0% + +okay so now they do the pyramidal tract + + align:start position:0% +okay so now they do the pyramidal tract + + + align:start position:0% +okay so now they do the pyramidal tract +lesion and we're going to see him this + + align:start position:0% +lesion and we're going to see him this + + + align:start position:0% +lesion and we're going to see him this +first monkey five months later + + align:start position:0% +first monkey five months later + + + align:start position:0% +first monkey five months later +after that bilateral section at behind + + align:start position:0% +after that bilateral section at behind + + + align:start position:0% +after that bilateral section at behind +brain level of the pyramidal tract + + align:start position:0% +brain level of the pyramidal tract + + + align:start position:0% +brain level of the pyramidal tract +and on these histological sections + + align:start position:0% +and on these histological sections + + + align:start position:0% +and on these histological sections +if they're standing for myelin see the + + align:start position:0% +if they're standing for myelin see the + + + align:start position:0% +if they're standing for myelin see the +one at the bottom it's white at the + + align:start position:0% +one at the bottom it's white at the + + + align:start position:0% +one at the bottom it's white at the +bottom because the paranal tract it's + + align:start position:0% +bottom because the paranal tract it's + + + align:start position:0% +bottom because the paranal tract it's +lost it smile and this section this + + align:start position:0% +lost it smile and this section this + + + align:start position:0% +lost it smile and this section this +section + + align:start position:0% +section + + + align:start position:0% +section +there you see some torn tissue but you + + align:start position:0% +there you see some torn tissue but you + + + align:start position:0% +there you see some torn tissue but you +also see these dark areas + + align:start position:0% +also see these dark areas + + + align:start position:0% +also see these dark areas +that's an accumulation of glial cells + + align:start position:0% +that's an accumulation of glial cells + + + align:start position:0% +that's an accumulation of glial cells +it's called gliosis that happens with + + align:start position:0% +it's called gliosis that happens with + + + align:start position:0% +it's called gliosis that happens with +lesions okay + + align:start position:0% +lesions okay + + + align:start position:0% +lesions okay +the the glial cells are phagocytic they + + align:start position:0% +the the glial cells are phagocytic they + + + align:start position:0% +the the glial cells are phagocytic they +eat up the dead tissue and they + + align:start position:0% +eat up the dead tissue and they + + + align:start position:0% +eat up the dead tissue and they +accumulate and remain in these these + + align:start position:0% +accumulate and remain in these these + + + align:start position:0% +accumulate and remain in these these +lesions at least some of them remain + + align:start position:0% +lesions at least some of them remain + + + align:start position:0% +lesions at least some of them remain +okay so now this is five months he's + + align:start position:0% +okay so now this is five months he's + + + align:start position:0% +okay so now this is five months he's +recovered pretty well and pay attention + + align:start position:0% +recovered pretty well and pay attention + + + align:start position:0% +recovered pretty well and pay attention +to how he's using the hands he's not + + align:start position:0% +to how he's using the hands he's not + + + align:start position:0% +to how he's using the hands he's not +quite as fast but you will see that he + + align:start position:0% +quite as fast but you will see that he + + + align:start position:0% +quite as fast but you will see that he +moves the into all his fingers together + + align:start position:0% +moves the into all his fingers together + + + align:start position:0% +moves the into all his fingers together +like a baby grasping something + + align:start position:0% +like a baby grasping something + + + align:start position:0% +like a baby grasping something +okay a baby a newer human in the first + + align:start position:0% +okay a baby a newer human in the first + + + align:start position:0% +okay a baby a newer human in the first +few months of life doesn't have + + align:start position:0% +few months of life doesn't have + + + align:start position:0% +few months of life doesn't have +pyramidal track connections yet so he + + align:start position:0% +pyramidal track connections yet so he + + + align:start position:0% +pyramidal track connections yet so he +moves his hand like this + + align:start position:0% + + + + align:start position:0% + +or she's + + align:start position:0% + + + + align:start position:0% + +and you'll see that's pretty consistent + + align:start position:0% +and you'll see that's pretty consistent + + + align:start position:0% +and you'll see that's pretty consistent +here they use the whole hand together + + align:start position:0% + + + + align:start position:0% + +they have pretty good control + + align:start position:0% +they have pretty good control + + + align:start position:0% +they have pretty good control +they tend to flex a little more than + + align:start position:0% +they tend to flex a little more than + + + align:start position:0% +they tend to flex a little more than +usual they have a flexor bias so they + + align:start position:0% +usual they have a flexor bias so they + + + align:start position:0% +usual they have a flexor bias so they +have to move the board a little closer + + align:start position:0% +have to move the board a little closer + + + align:start position:0% +have to move the board a little closer +but he can definitely + + align:start position:0% +but he can definitely + + + align:start position:0% +but he can definitely +do it + + align:start position:0% +do it + + + align:start position:0% +do it +now if you look + + align:start position:0% +now if you look + + + align:start position:0% +now if you look +sooner after the lesion you'll see a + + align:start position:0% +sooner after the lesion you'll see a + + + align:start position:0% +sooner after the lesion you'll see a +greater impairment because of the + + align:start position:0% +greater impairment because of the + + + align:start position:0% +greater impairment because of the +diasthesis effects + + align:start position:0% +diasthesis effects + + + align:start position:0% +diasthesis effects +of the removal of all those axons to the + + align:start position:0% +of the removal of all those axons to the + + + align:start position:0% +of the removal of all those axons to the +cord + + align:start position:0% + + + + align:start position:0% + +and later when they did the histology + + align:start position:0% +and later when they did the histology + + + align:start position:0% +and later when they did the histology +you saw the demyelinization of the + + align:start position:0% +you saw the demyelinization of the + + + align:start position:0% +you saw the demyelinization of the +primal tract it appeared to be a + + align:start position:0% +primal tract it appeared to be a + + + align:start position:0% +primal tract it appeared to be a +complete lesion + + align:start position:0% +complete lesion + + + align:start position:0% +complete lesion +and here you see the gliosis in the + + align:start position:0% +and here you see the gliosis in the + + + align:start position:0% +and here you see the gliosis in the +primal tract here you see the torn + + align:start position:0% +primal tract here you see the torn + + + align:start position:0% +primal tract here you see the torn +picture so with enough sections you can + + align:start position:0% +picture so with enough sections you can + + + align:start position:0% +picture so with enough sections you can +reconstruct the pathway of the knife + + align:start position:0% + + + + align:start position:0% + +difficult surgery to do because if you + + align:start position:0% +difficult surgery to do because if you + + + align:start position:0% +difficult surgery to do because if you +don't do it right in this part of the + + align:start position:0% +don't do it right in this part of the + + + align:start position:0% +don't do it right in this part of the +brain the animal will lose + + align:start position:0% +brain the animal will lose + + + align:start position:0% +brain the animal will lose +vital functions + + align:start position:0% + + + + align:start position:0% + +first of all you see that he's actually + + align:start position:0% +first of all you see that he's actually + + + align:start position:0% +first of all you see that he's actually +able to climb + + align:start position:0% + + + + align:start position:0% + +his reflexes are slowed a bit + + align:start position:0% +his reflexes are slowed a bit + + + align:start position:0% +his reflexes are slowed a bit +but he's able to climb grasp his cage + + align:start position:0% +but he's able to climb grasp his cage + + + align:start position:0% +but he's able to climb grasp his cage +bars and so forth + + align:start position:0% +bars and so forth + + + align:start position:0% +bars and so forth +shows a lot of voluntary movement + + align:start position:0% + + + + align:start position:0% + +here's the slow placing reflexes + + align:start position:0% +here's the slow placing reflexes + + + align:start position:0% +here's the slow placing reflexes +when you touch his chin this should be + + align:start position:0% +when you touch his chin this should be + + + align:start position:0% +when you touch his chin this should be +the most this is the greatest impairment + + align:start position:0% +the most this is the greatest impairment + + + align:start position:0% +the most this is the greatest impairment +you'll see just after parameter + + align:start position:0% +you'll see just after parameter + + + align:start position:0% +you'll see just after parameter +pyramidal track section now just + + align:start position:0% +pyramidal track section now just + + + align:start position:0% +pyramidal track section now just +corticospinal tract axons + + align:start position:0% +corticospinal tract axons + + + align:start position:0% +corticospinal tract axons +their lesions were pretty good + + align:start position:0% +their lesions were pretty good + + + align:start position:0% +their lesions were pretty good +this + + align:start position:0% +this + + + align:start position:0% +this +this animal died earlier but you do see + + align:start position:0% +this animal died earlier but you do see + + + align:start position:0% +this animal died earlier but you do see +the course of the knife here it has not + + align:start position:0% +the course of the knife here it has not + + + align:start position:0% +the course of the knife here it has not +had time to accumulate too many of the + + align:start position:0% +had time to accumulate too many of the + + + align:start position:0% +had time to accumulate too many of the +glia + + align:start position:0% + + + + align:start position:0% + +now if they spare some of the primal + + align:start position:0% +now if they spare some of the primal + + + align:start position:0% +now if they spare some of the primal +tract you will get + + align:start position:0% +tract you will get + + + align:start position:0% +tract you will get +you will get some sparing of the + + align:start position:0% +you will get some sparing of the + + + align:start position:0% +you will get some sparing of the +individual digit control + + align:start position:0% +individual digit control + + + align:start position:0% +individual digit control +many pathways in the brain in order to + + align:start position:0% +many pathways in the brain in order to + + + align:start position:0% +many pathways in the brain in order to +get a complete deficit you pretty much + + align:start position:0% +get a complete deficit you pretty much + + + align:start position:0% +get a complete deficit you pretty much +have to get the entire thing + + align:start position:0% + + + + align:start position:0% + +so neurologists who have not seen this + + align:start position:0% +so neurologists who have not seen this + + + align:start position:0% +so neurologists who have not seen this +study and + + align:start position:0% +study and + + + align:start position:0% +study and +have not seen humans of course very rare + + align:start position:0% +have not seen humans of course very rare + + + align:start position:0% +have not seen humans of course very rare +will have a parallel track section like + + align:start position:0% +will have a parallel track section like + + + align:start position:0% +will have a parallel track section like +this + + align:start position:0% +this + + + align:start position:0% +this +they might be surprised that their + + align:start position:0% +they might be surprised that their + + + align:start position:0% +they might be surprised that their +textbooks + + align:start position:0% +textbooks + + + align:start position:0% +textbooks +are not correct about voluntary movement + + align:start position:0% +are not correct about voluntary movement + + + align:start position:0% +are not correct about voluntary movement +but notice here how he can climb + + align:start position:0% + + + + align:start position:0% + +sorry + + align:start position:0% +sorry + + + align:start position:0% +sorry +oh yes they can climb once they + + align:start position:0% +oh yes they can climb once they + + + align:start position:0% +oh yes they can climb once they +pretty much spinal mechanisms but they + + align:start position:0% +pretty much spinal mechanisms but they + + + align:start position:0% +pretty much spinal mechanisms but they +do learn of course + + align:start position:0% +do learn of course + + + align:start position:0% +do learn of course +details of + + align:start position:0% +details of + + + align:start position:0% +details of +cages + + align:start position:0% +cages + + + align:start position:0% +cages +compared with trees + + align:start position:0% + + + + align:start position:0% + +i think this animal when they feed him + + align:start position:0% +i think this animal when they feed him + + + align:start position:0% +i think this animal when they feed him +because he has difficulty reaching well + + align:start position:0% +because he has difficulty reaching well + + + align:start position:0% +because he has difficulty reaching well +he tries to get the food with like a dog + + align:start position:0% +he tries to get the food with like a dog + + + align:start position:0% +he tries to get the food with like a dog +just directly with his mouth + + align:start position:0% + + + + align:start position:0% + +they're just doing this to demonstrate + + align:start position:0% +they're just doing this to demonstrate + + + align:start position:0% +they're just doing this to demonstrate +that he has a lot of movement control + + align:start position:0% +that he has a lot of movement control + + + align:start position:0% +that he has a lot of movement control +left + + align:start position:0% +left + + + align:start position:0% +left +and here you see him he's a little + + align:start position:0% +and here you see him he's a little + + + align:start position:0% +and here you see him he's a little +reluctant to reach he wants to just + + align:start position:0% +reluctant to reach he wants to just + + + align:start position:0% +reluctant to reach he wants to just +reach out with his mouth and grab it + + align:start position:0% +reach out with his mouth and grab it + + + align:start position:0% +reach out with his mouth and grab it +because after just such a short time + + align:start position:0% +because after just such a short time + + + align:start position:0% +because after just such a short time +after the lesion he doesn't have good + + align:start position:0% +after the lesion he doesn't have good + + + align:start position:0% +after the lesion he doesn't have good +control of his hands + + align:start position:0% +control of his hands + + + align:start position:0% +control of his hands +okay but we know that not + + align:start position:0% +okay but we know that not + + + align:start position:0% +okay but we know that not +just give him a little time and that + + align:start position:0% +just give him a little time and that + + + align:start position:0% +just give him a little time and that +will come back + + align:start position:0% + + + + align:start position:0% + +now before this study was done i should + + align:start position:0% +now before this study was done i should + + + align:start position:0% +now before this study was done i should +point out that + + align:start position:0% +point out that + + + align:start position:0% +point out that +clinical + + align:start position:0% +clinical + + + align:start position:0% +clinical +neurologist you know we're + + align:start position:0% +neurologist you know we're + + + align:start position:0% +neurologist you know we're +a little bit in the dark about + + align:start position:0% +a little bit in the dark about + + + align:start position:0% +a little bit in the dark about +what + + align:start position:0% +what + + + align:start position:0% +what +these lesions would do and so it was a + + align:start position:0% +these lesions would do and so it was a + + + align:start position:0% +these lesions would do and so it was a +very important study for human clinic + + align:start position:0% +very important study for human clinic + + + align:start position:0% +very important study for human clinic +okay so now remember these animals now + + align:start position:0% +okay so now remember these animals now + + + align:start position:0% +okay so now remember these animals now +you'll see all had the pyramid atomy + + align:start position:0% +you'll see all had the pyramid atomy + + + align:start position:0% +you'll see all had the pyramid atomy +first + + align:start position:0% +first + + + align:start position:0% +first +okay and there's the + + align:start position:0% +okay and there's the + + + align:start position:0% +okay and there's the +demolition of the pyramidal track the + + align:start position:0% +demolition of the pyramidal track the + + + align:start position:0% +demolition of the pyramidal track the +gliosis the pyramidal track but here + + align:start position:0% +gliosis the pyramidal track but here + + + align:start position:0% +gliosis the pyramidal track but here +they've shown you with they've drawn + + align:start position:0% +they've shown you with they've drawn + + + align:start position:0% +they've shown you with they've drawn +onto the section here the reconstructed + + align:start position:0% +onto the section here the reconstructed + + + align:start position:0% +onto the section here the reconstructed +path + + align:start position:0% +path + + + align:start position:0% +path +of the knife + + align:start position:0% +of the knife + + + align:start position:0% +of the knife +that so that in addition to the primal + + align:start position:0% +that so that in addition to the primal + + + align:start position:0% +that so that in addition to the primal +track section now they move the knife + + align:start position:0% +track section now they move the knife + + + align:start position:0% +track section now they move the knife +that + + align:start position:0% +that + + + align:start position:0% +that +through the brain stem so it cut all the + + align:start position:0% +through the brain stem so it cut all the + + + align:start position:0% +through the brain stem so it cut all the +pathways that travel medially in the + + align:start position:0% +pathways that travel medially in the + + + align:start position:0% +pathways that travel medially in the +hind brain all right + + align:start position:0% +hind brain all right + + + align:start position:0% +hind brain all right +so this will be the most impaired animal + + align:start position:0% +so this will be the most impaired animal + + + align:start position:0% +so this will be the most impaired animal +you'll see + + align:start position:0% +you'll see + + + align:start position:0% +you'll see +i know it's a little disturbing to some + + align:start position:0% +i know it's a little disturbing to some + + + align:start position:0% +i know it's a little disturbing to some +of you to see the animal that can't get + + align:start position:0% +of you to see the animal that can't get + + + align:start position:0% +of you to see the animal that can't get +up + + align:start position:0% +up + + + align:start position:0% +up +but it didn't last forever + + align:start position:0% +but it didn't last forever + + + align:start position:0% +but it didn't last forever +but he's + + align:start position:0% +but he's + + + align:start position:0% +but he's +now with no pyramidal tract and without + + align:start position:0% +now with no pyramidal tract and without + + + align:start position:0% +now with no pyramidal tract and without +the medial pathways he's + + align:start position:0% +the medial pathways he's + + + align:start position:0% +the medial pathways he's +he doesn't have good axial control + + align:start position:0% +he doesn't have good axial control + + + align:start position:0% +he doesn't have good axial control +okay so he doesn't have his writing + + align:start position:0% +okay so he doesn't have his writing + + + align:start position:0% +okay so he doesn't have his writing +responses it was only with recovery from + + align:start position:0% +responses it was only with recovery from + + + align:start position:0% +responses it was only with recovery from +diasthesis that he was able then to + + align:start position:0% +diasthesis that he was able then to + + + align:start position:0% +diasthesis that he was able then to +recover some sensory control final + + align:start position:0% +recover some sensory control final + + + align:start position:0% +recover some sensory control final +control of writing and he was able to + + align:start position:0% +control of writing and he was able to + + + align:start position:0% +control of writing and he was able to +get up after 40 days + + align:start position:0% + + + + align:start position:0% + +and you'll see in a minute here that + + align:start position:0% +and you'll see in a minute here that + + + align:start position:0% +and you'll see in a minute here that +these animals that can be so entirely + + align:start position:0% +these animals that can be so entirely + + + align:start position:0% +these animals that can be so entirely +almost helpless in these situations + + align:start position:0% +almost helpless in these situations + + + align:start position:0% +almost helpless in these situations +actually have quite a bit of control for + + align:start position:0% +actually have quite a bit of control for + + + align:start position:0% +actually have quite a bit of control for +one thing they have good head control + + align:start position:0% +one thing they have good head control + + + align:start position:0% +one thing they have good head control +this is now + + align:start position:0% +this is now + + + align:start position:0% +this is now +a little later + + align:start position:0% +a little later + + + align:start position:0% +a little later +five months after param diatomy one + + align:start position:0% +five months after param diatomy one + + + align:start position:0% +five months after param diatomy one +month after the medial reticular + + align:start position:0% +month after the medial reticular + + + align:start position:0% +month after the medial reticular +formation lesion + + align:start position:0% +formation lesion + + + align:start position:0% +formation lesion +it's a different animal they're showing + + align:start position:0% +it's a different animal they're showing + + + align:start position:0% +it's a different animal they're showing +the lesion here + + align:start position:0% + + + + align:start position:0% + +showing the gliosis in the pyramidal + + align:start position:0% +showing the gliosis in the pyramidal + + + align:start position:0% +showing the gliosis in the pyramidal +tract and there you can see + + align:start position:0% +tract and there you can see + + + align:start position:0% +tract and there you can see +where the knife passed the medial lesion + + align:start position:0% + + + + align:start position:0% + +they're not showing the midbrain so we + + align:start position:0% +they're not showing the midbrain so we + + + align:start position:0% +they're not showing the midbrain so we +can't see the red nucleus but they did + + align:start position:0% +can't see the red nucleus but they did + + + align:start position:0% +can't see the red nucleus but they did +look at that and they know they spared + + align:start position:0% +look at that and they know they spared + + + align:start position:0% +look at that and they know they spared +the lateral brainstem pathways that come + + align:start position:0% +the lateral brainstem pathways that come + + + align:start position:0% +the lateral brainstem pathways that come +from the red nucleus + + align:start position:0% + + + + align:start position:0% + +they'll show those sections when they in + + align:start position:0% +they'll show those sections when they in + + + align:start position:0% +they'll show those sections when they in +the cases where they did that lesion + + align:start position:0% + + + + align:start position:0% + +they cut off a lot of the section the + + align:start position:0% +they cut off a lot of the section the + + + align:start position:0% +they cut off a lot of the section the +cerebellum would be + + align:start position:0% +cerebellum would be + + + align:start position:0% +cerebellum would be +huge here in the monkey + + align:start position:0% + + + + align:start position:0% + +and these are at + + align:start position:0% +and these are at + + + align:start position:0% +and these are at +this one is at the cerebellar level + + align:start position:0% +this one is at the cerebellar level + + + align:start position:0% +this one is at the cerebellar level +and there you see a little bit of + + align:start position:0% +and there you see a little bit of + + + align:start position:0% +and there you see a little bit of +cerebellum at the top there that's + + align:start position:0% +cerebellum at the top there that's + + + align:start position:0% +cerebellum at the top there that's +cerebellar granule cells + + align:start position:0% + + + + align:start position:0% + +okay now they're starting out with + + align:start position:0% +okay now they're starting out with + + + align:start position:0% +okay now they're starting out with +showing the animal in the reaching + + align:start position:0% +showing the animal in the reaching + + + align:start position:0% +showing the animal in the reaching +situation now he's strapped to the chair + + align:start position:0% +situation now he's strapped to the chair + + + align:start position:0% +situation now he's strapped to the chair +they have to strap into the chair + + align:start position:0% +they have to strap into the chair + + + align:start position:0% +they have to strap into the chair +because he doesn't have good balance so + + align:start position:0% +because he doesn't have good balance so + + + align:start position:0% +because he doesn't have good balance so +they they hold him like + + align:start position:0% +they they hold him like + + + align:start position:0% +they they hold him like +that and now he's holding his arms and + + align:start position:0% +that and now he's holding his arms and + + + align:start position:0% +that and now he's holding his arms and +usually flex but in fact he can grasp + + align:start position:0% +usually flex but in fact he can grasp + + + align:start position:0% +usually flex but in fact he can grasp +the food + + align:start position:0% + + + + align:start position:0% + +as long as they allow him to + + align:start position:0% +as long as they allow him to + + + align:start position:0% +as long as they allow him to +be a little bit hyper flexed he can + + align:start position:0% +be a little bit hyper flexed he can + + + align:start position:0% +be a little bit hyper flexed he can +grasp the food he does it with whole + + align:start position:0% +grasp the food he does it with whole + + + align:start position:0% +grasp the food he does it with whole +hand movements he's still pretty slow + + align:start position:0% +hand movements he's still pretty slow + + + align:start position:0% +hand movements he's still pretty slow +because he hasn't recovered enough from + + align:start position:0% +because he hasn't recovered enough from + + + align:start position:0% +because he hasn't recovered enough from +the lesion yet so this is just a month + + align:start position:0% +the lesion yet so this is just a month + + + align:start position:0% +the lesion yet so this is just a month +later + + align:start position:0% + + + + align:start position:0% + +and you see he's recovered a little bit + + align:start position:0% +and you see he's recovered a little bit + + + align:start position:0% +and you see he's recovered a little bit +he's now better at grasping the apple + + align:start position:0% + + + + align:start position:0% + +and we'll see later that that movement + + align:start position:0% +and we'll see later that that movement + + + align:start position:0% +and we'll see later that that movement +is more dependent on that pathway from + + align:start position:0% +is more dependent on that pathway from + + + align:start position:0% +is more dependent on that pathway from +the midbrain from the red nucleus + + align:start position:0% + + + + align:start position:0% + +again they're holding one hand down so + + align:start position:0% +again they're holding one hand down so + + + align:start position:0% +again they're holding one hand down so +you can just use one at a time + + align:start position:0% +you can just use one at a time + + + align:start position:0% +you can just use one at a time +they test the two hands separately + + align:start position:0% + + + + align:start position:0% + +when they offer him + + align:start position:0% +when they offer him + + + align:start position:0% +when they offer him +when he has to use one digit to get the + + align:start position:0% +when he has to use one digit to get the + + + align:start position:0% +when he has to use one digit to get the +apple out of the small holes he can't do + + align:start position:0% +apple out of the small holes he can't do + + + align:start position:0% +apple out of the small holes he can't do +it + + align:start position:0% + + + + align:start position:0% + +it shows that he's got pretty vigorous + + align:start position:0% +it shows that he's got pretty vigorous + + + align:start position:0% +it shows that he's got pretty vigorous +responses of his limbs in the tests of + + align:start position:0% +responses of his limbs in the tests of + + + align:start position:0% +responses of his limbs in the tests of +placing + + align:start position:0% + + + + align:start position:0% + +you know this is a different monkey + + align:start position:0% +you know this is a different monkey + + + align:start position:0% +you know this is a different monkey +again with the pyramidal tract lesion + + align:start position:0% +again with the pyramidal tract lesion + + + align:start position:0% +again with the pyramidal tract lesion +and then two months after the medial + + align:start position:0% +and then two months after the medial + + + align:start position:0% +and then two months after the medial +hind brain reticular formation so this + + align:start position:0% +hind brain reticular formation so this + + + align:start position:0% +hind brain reticular formation so this +is just a replication + + align:start position:0% +is just a replication + + + align:start position:0% +is just a replication +of that experiment + + align:start position:0% +of that experiment + + + align:start position:0% +of that experiment +you see the + + align:start position:0% +you see the + + + align:start position:0% +you see the +demyelinization and the gliosis and the + + align:start position:0% +demyelinization and the gliosis and the + + + align:start position:0% +demyelinization and the gliosis and the +primal tract + + align:start position:0% +primal tract + + + align:start position:0% +primal tract +and then the reconstruction of the you + + align:start position:0% +and then the reconstruction of the you + + + align:start position:0% +and then the reconstruction of the you +see a little bit of the lesion here + + align:start position:0% +see a little bit of the lesion here + + + align:start position:0% +see a little bit of the lesion here +nucleotic areas + + align:start position:0% +nucleotic areas + + + align:start position:0% +nucleotic areas +you need to see all the sections + + align:start position:0% +you need to see all the sections + + + align:start position:0% +you need to see all the sections +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so this animal when he walks + + align:start position:0% +so this animal when he walks + + + align:start position:0% +so this animal when he walks +in very good poor control of his + + align:start position:0% +in very good poor control of his + + + align:start position:0% +in very good poor control of his +direction + + align:start position:0% +direction + + + align:start position:0% +direction +you know + + align:start position:0% + + + + align:start position:0% + +they're just making him and there he + + align:start position:0% +they're just making him and there he + + + align:start position:0% +they're just making him and there he +falls over + + align:start position:0% +falls over + + + align:start position:0% +falls over +and you see he wasn't able to write + + align:start position:0% +and you see he wasn't able to write + + + align:start position:0% +and you see he wasn't able to write +himself very rapidly his medicine + + align:start position:0% +himself very rapidly his medicine + + + align:start position:0% +himself very rapidly his medicine +writing responses haven't + + align:start position:0% +writing responses haven't + + + align:start position:0% +writing responses haven't +come back much + + align:start position:0% +come back much + + + align:start position:0% +come back much +of course now if this were a normal + + align:start position:0% +of course now if this were a normal + + + align:start position:0% +of course now if this were a normal +monkey he would just pick it up + + align:start position:0% +monkey he would just pick it up + + + align:start position:0% +monkey he would just pick it up +but without the primal trackies a little + + align:start position:0% +but without the primal trackies a little + + + align:start position:0% +but without the primal trackies a little +more like a dog + + align:start position:0% +more like a dog + + + align:start position:0% +more like a dog +in the way he responds + + align:start position:0% + + + + align:start position:0% + +very unsteady with the lack of + + align:start position:0% +very unsteady with the lack of + + + align:start position:0% +very unsteady with the lack of +vestibular spinal + + align:start position:0% +vestibular spinal + + + align:start position:0% +vestibular spinal +and without the tactile spinal he's also + + align:start position:0% +and without the tactile spinal he's also + + + align:start position:0% +and without the tactile spinal he's also +not very good at orienting his head and + + align:start position:0% +not very good at orienting his head and + + + align:start position:0% +not very good at orienting his head and +eyes + + align:start position:0% +eyes + + + align:start position:0% +eyes +his eye movements by the way are + + align:start position:0% +his eye movements by the way are + + + align:start position:0% +his eye movements by the way are +actually pretty normal if you + + align:start position:0% +actually pretty normal if you + + + align:start position:0% +actually pretty normal if you +see him in the chair and study them and + + align:start position:0% +see him in the chair and study them and + + + align:start position:0% +see him in the chair and study them and +that's because he has the connections to + + align:start position:0% +that's because he has the connections to + + + align:start position:0% +that's because he has the connections to +the ocular motor nuclei intact + + align:start position:0% +the ocular motor nuclei intact + + + align:start position:0% +the ocular motor nuclei intact +they've cut those pathways further down + + align:start position:0% +they've cut those pathways further down + + + align:start position:0% +they've cut those pathways further down +behind brain + + align:start position:0% + + + + align:start position:0% + +okay so now this will be the first of + + align:start position:0% +okay so now this will be the first of + + + align:start position:0% +okay so now this will be the first of +the + + align:start position:0% +the + + + align:start position:0% +the +third type of animal where they have + + align:start position:0% +third type of animal where they have + + + align:start position:0% +third type of animal where they have +paramidotomy first and then + + align:start position:0% +paramidotomy first and then + + + align:start position:0% +paramidotomy first and then +this is just a short a few days five + + align:start position:0% +this is just a short a few days five + + + align:start position:0% +this is just a short a few days five +days after the lesion of the lateral + + align:start position:0% + + + + align:start position:0% + +behind brain you see it right here + + align:start position:0% +behind brain you see it right here + + + align:start position:0% +behind brain you see it right here +he's missing the primal tract + + align:start position:0% + + + + align:start position:0% + +this is working less and less okay there + + align:start position:0% +this is working less and less okay there + + + align:start position:0% +this is working less and less okay there +you see it + + align:start position:0% +you see it + + + align:start position:0% +you see it +see the gliosis + + align:start position:0% +see the gliosis + + + align:start position:0% +see the gliosis +and the question is now did they cut the + + align:start position:0% +and the question is now did they cut the + + + align:start position:0% +and the question is now did they cut the +ribospinal tract if you look up here + + align:start position:0% +ribospinal tract if you look up here + + + align:start position:0% +ribospinal tract if you look up here +there's some big neurons in the red + + align:start position:0% +there's some big neurons in the red + + + align:start position:0% +there's some big neurons in the red +nucleus there and we can't see any there + + align:start position:0% +nucleus there and we can't see any there + + + align:start position:0% +nucleus there and we can't see any there +in the red nucleus in the midbrain this + + align:start position:0% +in the red nucleus in the midbrain this + + + align:start position:0% +in the red nucleus in the midbrain this +is midbrain level that's the + + align:start position:0% +is midbrain level that's the + + + align:start position:0% +is midbrain level that's the +the + + align:start position:0% +the + + + align:start position:0% +the +cerebral peduncle down there + + align:start position:0% +cerebral peduncle down there + + + align:start position:0% +cerebral peduncle down there +okay so it looks like a good lesion even + + align:start position:0% +okay so it looks like a good lesion even + + + align:start position:0% +okay so it looks like a good lesion even +though it was small it seemed to have + + align:start position:0% +though it was small it seemed to have + + + align:start position:0% +though it was small it seemed to have +severed the ribospinal tract in the + + align:start position:0% +severed the ribospinal tract in the + + + align:start position:0% +severed the ribospinal tract in the +hindbrain + + align:start position:0% + + + + align:start position:0% + +now they're going to test the two hands + + align:start position:0% +now they're going to test the two hands + + + align:start position:0% +now they're going to test the two hands +separately + + align:start position:0% +separately + + + align:start position:0% +separately +you see the left hand + + align:start position:0% +you see the left hand + + + align:start position:0% +you see the left hand +is pretty good and he can reach he's got + + align:start position:0% +is pretty good and he can reach he's got + + + align:start position:0% +is pretty good and he can reach he's got +some control of his shoulders + + align:start position:0% +some control of his shoulders + + + align:start position:0% +some control of his shoulders +but very very poor control almost no + + align:start position:0% +but very very poor control almost no + + + align:start position:0% +but very very poor control almost no +control now left of his + + align:start position:0% +control now left of his + + + align:start position:0% +control now left of his +most distal muscles there with the left + + align:start position:0% +most distal muscles there with the left + + + align:start position:0% +most distal muscles there with the left +hand + + align:start position:0% + + + + align:start position:0% + +if he can he learns later to sort of + + align:start position:0% +if he can he learns later to sort of + + + align:start position:0% +if he can he learns later to sort of +engage his whole body in doing it and + + align:start position:0% +engage his whole body in doing it and + + + align:start position:0% +engage his whole body in doing it and +then sometimes he can get the spinal + + align:start position:0% +then sometimes he can get the spinal + + + align:start position:0% +then sometimes he can get the spinal +mechanisms of whole body control + + align:start position:0% +mechanisms of whole body control + + + align:start position:0% +mechanisms of whole body control +activated and he gets a little bit + + align:start position:0% +activated and he gets a little bit + + + align:start position:0% +activated and he gets a little bit +better control of that + + align:start position:0% + + + + align:start position:0% + +okay so we'll see him one and then two + + align:start position:0% +okay so we'll see him one and then two + + + align:start position:0% +okay so we'll see him one and then two +months after the right + + align:start position:0% +months after the right + + + align:start position:0% +months after the right +lateral pontine lesion so the same + + align:start position:0% +lateral pontine lesion so the same + + + align:start position:0% +lateral pontine lesion so the same +simulation + + align:start position:0% + + + + align:start position:0% + +the hand that's not affected + + align:start position:0% +the hand that's not affected + + + align:start position:0% +the hand that's not affected +by the + + align:start position:0% + + + + align:start position:0% + +section of the descending lateral + + align:start position:0% +section of the descending lateral + + + align:start position:0% +section of the descending lateral +pathway + + align:start position:0% +pathway + + + align:start position:0% +pathway +and here's the side that is affected + + align:start position:0% +and here's the side that is affected + + + align:start position:0% +and here's the side that is affected +and again if they let him engage his + + align:start position:0% +and again if they let him engage his + + + align:start position:0% +and again if they let him engage his +whole arm + + align:start position:0% +whole arm + + + align:start position:0% +whole arm +he can sometimes do it he's learned a + + align:start position:0% +he can sometimes do it he's learned a + + + align:start position:0% +he can sometimes do it he's learned a +little bit about that but + + align:start position:0% +little bit about that but + + + align:start position:0% +little bit about that but +if he doesn't get his whole body + + align:start position:0% +if he doesn't get his whole body + + + align:start position:0% +if he doesn't get his whole body +and doing it + + align:start position:0% +and doing it + + + align:start position:0% +and doing it +he can't + + align:start position:0% +he can't + + + align:start position:0% +he can't +he doesn't have good individual control + + align:start position:0% +he doesn't have good individual control + + + align:start position:0% +he doesn't have good individual control +of the hand at all + + align:start position:0% +of the hand at all + + + align:start position:0% +of the hand at all +so much worse than just the medial + + align:start position:0% +so much worse than just the medial + + + align:start position:0% +so much worse than just the medial +pathway + + align:start position:0% +pathway + + + align:start position:0% +pathway +sorry just the pyramidal tract + + align:start position:0% +sorry just the pyramidal tract + + + align:start position:0% +sorry just the pyramidal tract +it's it's added a considerable amount of + + align:start position:0% +it's it's added a considerable amount of + + + align:start position:0% +it's it's added a considerable amount of +deficiency to the + + align:start position:0% +deficiency to the + + + align:start position:0% +deficiency to the +control of the hand + + align:start position:0% + + + + align:start position:0% + +and then you'll see that something quite + + align:start position:0% +and then you'll see that something quite + + + align:start position:0% +and then you'll see that something quite +remarkable here in a minute + + align:start position:0% + + + + align:start position:0% + +poor individual control when they're + + align:start position:0% +poor individual control when they're + + + align:start position:0% +poor individual control when they're +getting to use that limb by itself + + align:start position:0% + + + + align:start position:0% + +here they're just showing that it + + align:start position:0% +here they're just showing that it + + + align:start position:0% +here they're just showing that it +doesn't depend on + + align:start position:0% +doesn't depend on + + + align:start position:0% +doesn't depend on +his posture some there are some + + align:start position:0% +his posture some there are some + + + align:start position:0% +his posture some there are some +neurological deficits where you change + + align:start position:0% +neurological deficits where you change + + + align:start position:0% +neurological deficits where you change +the posture they might do a lot better + + align:start position:0% +the posture they might do a lot better + + + align:start position:0% +the posture they might do a lot better +but you'll see is about the same + + align:start position:0% +but you'll see is about the same + + + align:start position:0% +but you'll see is about the same +in this posture + + align:start position:0% +in this posture + + + align:start position:0% +in this posture +i can control the arm a little bit from + + align:start position:0% +i can control the arm a little bit from + + + align:start position:0% +i can control the arm a little bit from +the shoulder but that's about it + + align:start position:0% +the shoulder but that's about it + + + align:start position:0% +the shoulder but that's about it +unless he can make his scooping movement + + align:start position:0% +unless he can make his scooping movement + + + align:start position:0% +unless he can make his scooping movement +with his whole body + + align:start position:0% + + + + align:start position:0% + +and they tried very hard to get them to + + align:start position:0% +and they tried very hard to get them to + + + align:start position:0% +and they tried very hard to get them to +recover and they they did get a little + + align:start position:0% +recover and they they did get a little + + + align:start position:0% +recover and they they did get a little +bit it was important for the human + + align:start position:0% +bit it was important for the human + + + align:start position:0% +bit it was important for the human +studies to know just how far can the + + align:start position:0% +studies to know just how far can the + + + align:start position:0% +studies to know just how far can the +recovery go + + align:start position:0% +recovery go + + + align:start position:0% +recovery go +you know and there's anything they could + + align:start position:0% +you know and there's anything they could + + + align:start position:0% +you know and there's anything they could +do to promote it + + align:start position:0% + + + + align:start position:0% + +and now you'll see some other responses + + align:start position:0% +and now you'll see some other responses + + + align:start position:0% +and now you'll see some other responses +where he's now + + align:start position:0% + + + + align:start position:0% + +able to use whole body movements more + + align:start position:0% +able to use whole body movements more + + + align:start position:0% +able to use whole body movements more +and you'll see it's much harder now to + + align:start position:0% +and you'll see it's much harder now to + + + align:start position:0% +and you'll see it's much harder now to +tell which is the limb affected by the + + align:start position:0% +tell which is the limb affected by the + + + align:start position:0% +tell which is the limb affected by the +that + + align:start position:0% +that + + + align:start position:0% +that +lesion + + align:start position:0% +lesion + + + align:start position:0% +lesion +especially here he's using both hands + + align:start position:0% +especially here he's using both hands + + + align:start position:0% +especially here he's using both hands +he's grasping the cage + + align:start position:0% +he's grasping the cage + + + align:start position:0% +he's grasping the cage +the same hand that could not grasp the + + align:start position:0% +the same hand that could not grasp the + + + align:start position:0% +the same hand that could not grasp the +apple pieces is grasping the cage why + + align:start position:0% +apple pieces is grasping the cage why + + + align:start position:0% +apple pieces is grasping the cage why +because when we think of the word + + align:start position:0% +because when we think of the word + + + align:start position:0% +because when we think of the word +paralysis + + align:start position:0% +paralysis + + + align:start position:0% +paralysis +it's sometimes very specific to the type + + align:start position:0% +it's sometimes very specific to the type + + + align:start position:0% +it's sometimes very specific to the type +of movement + + align:start position:0% +of movement + + + align:start position:0% +of movement +okay he cannot use the hand in one + + align:start position:0% +okay he cannot use the hand in one + + + align:start position:0% +okay he cannot use the hand in one +situation + + align:start position:0% +situation + + + align:start position:0% +situation +but in climbing + + align:start position:0% +but in climbing + + + align:start position:0% +but in climbing +fixed action patterns governed by a + + align:start position:0% +fixed action patterns governed by a + + + align:start position:0% +fixed action patterns governed by a +hindbrain and spinal cord he can do + + align:start position:0% +hindbrain and spinal cord he can do + + + align:start position:0% +hindbrain and spinal cord he can do +quite well + + align:start position:0% +quite well + + + align:start position:0% +quite well +okay + + align:start position:0% +okay + + + align:start position:0% +okay +that's an important point + + align:start position:0% +that's an important point + + + align:start position:0% +that's an important point +this is the very same animal + + align:start position:0% +this is the very same animal + + + align:start position:0% +this is the very same animal +very hard to tell which is the defective + + align:start position:0% +very hard to tell which is the defective + + + align:start position:0% +very hard to tell which is the defective +hand + + align:start position:0% +hand + + + align:start position:0% +hand +so this is now + + align:start position:0% +so this is now + + + align:start position:0% +so this is now +a similar + + align:start position:0% +a similar + + + align:start position:0% +a similar +replication of that experiment + + align:start position:0% + + + + align:start position:0% + +in this case though + + align:start position:0% +in this case though + + + align:start position:0% +in this case though +the lesion of the hindbrain it looks + + align:start position:0% +the lesion of the hindbrain it looks + + + align:start position:0% +the lesion of the hindbrain it looks +larger here but in fact they missed some + + align:start position:0% +larger here but in fact they missed some + + + align:start position:0% +larger here but in fact they missed some +of the rubospinal tract because you see + + align:start position:0% +of the rubospinal tract because you see + + + align:start position:0% +of the rubospinal tract because you see +some large neurons here in the red + + align:start position:0% +some large neurons here in the red + + + align:start position:0% +some large neurons here in the red +nucleus soy if i'm right i think this + + align:start position:0% +nucleus soy if i'm right i think this + + + align:start position:0% +nucleus soy if i'm right i think this +animal shows more sparing + + align:start position:0% +animal shows more sparing + + + align:start position:0% +animal shows more sparing +that was why it's always important when + + align:start position:0% +that was why it's always important when + + + align:start position:0% +that was why it's always important when +you do such studies to do careful + + align:start position:0% +you do such studies to do careful + + + align:start position:0% +you do such studies to do careful +histology and do your best to + + align:start position:0% +histology and do your best to + + + align:start position:0% +histology and do your best to +reconstruct exactly what you did in the + + align:start position:0% +reconstruct exactly what you did in the + + + align:start position:0% +reconstruct exactly what you did in the +surgery + + align:start position:0% +surgery + + + align:start position:0% +surgery +it's not always possible to control it + + align:start position:0% +it's not always possible to control it + + + align:start position:0% +it's not always possible to control it +perfectly and also there's a little bit + + align:start position:0% +perfectly and also there's a little bit + + + align:start position:0% +perfectly and also there's a little bit +of variation + + align:start position:0% +of variation + + + align:start position:0% +of variation +from animal to animal and exactly how + + align:start position:0% +from animal to animal and exactly how + + + align:start position:0% +from animal to animal and exactly how +those pathways travel + + align:start position:0% + + + + align:start position:0% + +see the central gray there + + align:start position:0% +see the central gray there + + + align:start position:0% +see the central gray there +several pineapples down here + + align:start position:0% +several pineapples down here + + + align:start position:0% +several pineapples down here +this would + + align:start position:0% + + + + align:start position:0% + +it's + + align:start position:0% +it's + + + align:start position:0% +it's +certainly deficient but + + align:start position:0% + + + + align:start position:0% + +more control than the other animals + + align:start position:0% +more control than the other animals + + + align:start position:0% +more control than the other animals +just with the sparing of a + + align:start position:0% +just with the sparing of a + + + align:start position:0% +just with the sparing of a +small part + + align:start position:0% +small part + + + align:start position:0% +small part +of that pathway + + align:start position:0% +of that pathway + + + align:start position:0% +of that pathway +and that's why in human cases + + align:start position:0% + + + + align:start position:0% + +a tumor or something that's gradually + + align:start position:0% +a tumor or something that's gradually + + + align:start position:0% +a tumor or something that's gradually +destroying more and more of a pathway + + align:start position:0% +destroying more and more of a pathway + + + align:start position:0% +destroying more and more of a pathway +sometimes you will not see the defect + + align:start position:0% +sometimes you will not see the defect + + + align:start position:0% +sometimes you will not see the defect +until it's almost completely destroyed a + + align:start position:0% +until it's almost completely destroyed a + + + align:start position:0% +until it's almost completely destroyed a +pathway + + align:start position:0% + + + + align:start position:0% + +okay now here they're making the lesion + + align:start position:0% +okay now here they're making the lesion + + + align:start position:0% +okay now here they're making the lesion +further down so now they're getting the + + align:start position:0% +further down so now they're getting the + + + align:start position:0% +further down so now they're getting the +lateral pathway + + align:start position:0% +lateral pathway + + + align:start position:0% +lateral pathway +in the medullary region + + align:start position:0% +in the medullary region + + + align:start position:0% +in the medullary region +it's a little easier to get all of it + + align:start position:0% +it's a little easier to get all of it + + + align:start position:0% +it's a little easier to get all of it +here you see in the this is medulla + + align:start position:0% +here you see in the this is medulla + + + align:start position:0% +here you see in the this is medulla +oblongata the coral part of the + + align:start position:0% +oblongata the coral part of the + + + align:start position:0% +oblongata the coral part of the +hindbrain and you see the lesion there + + align:start position:0% +hindbrain and you see the lesion there + + + align:start position:0% +hindbrain and you see the lesion there +an animal had already had the primal + + align:start position:0% +an animal had already had the primal + + + align:start position:0% +an animal had already had the primal +tract and here's the red nucleus with + + align:start position:0% +tract and here's the red nucleus with + + + align:start position:0% +tract and here's the red nucleus with +neurons on this side and not on this + + align:start position:0% +neurons on this side and not on this + + + align:start position:0% +neurons on this side and not on this +side these are akira motor nuclei here + + align:start position:0% +side these are akira motor nuclei here + + + align:start position:0% +side these are akira motor nuclei here +there's the central gray there's the + + align:start position:0% +there's the central gray there's the + + + align:start position:0% +there's the central gray there's the +aqueduct of silvius going through the + + align:start position:0% +aqueduct of silvius going through the + + + align:start position:0% +aqueduct of silvius going through the +midbrain + + align:start position:0% + + + + align:start position:0% + +here's the larger ventricle and the + + align:start position:0% +here's the larger ventricle and the + + + align:start position:0% +here's the larger ventricle and the +fourth ventricle the hindbrain + + align:start position:0% + + + + align:start position:0% + +the cola hindbrain is looking more like + + align:start position:0% +the cola hindbrain is looking more like + + + align:start position:0% +the cola hindbrain is looking more like +spinal cord but you can still see the + + align:start position:0% +spinal cord but you can still see the + + + align:start position:0% +spinal cord but you can still see the +widened ventricle there + + align:start position:0% +widened ventricle there + + + align:start position:0% +widened ventricle there +here you're almost at the beginning of + + align:start position:0% +here you're almost at the beginning of + + + align:start position:0% +here you're almost at the beginning of +the spinal cord + + align:start position:0% + + + + align:start position:0% + +i think we'll look at this one and then + + align:start position:0% +i think we'll look at this one and then + + + align:start position:0% +i think we'll look at this one and then +we won't look at any more because at the + + align:start position:0% +we won't look at any more because at the + + + align:start position:0% +we won't look at any more because at the +time they do some control experiments + + align:start position:0% +time they do some control experiments + + + align:start position:0% +time they do some control experiments +where they + + align:start position:0% +where they + + + align:start position:0% +where they +they look to just make sure they're not + + align:start position:0% +they look to just make sure they're not + + + align:start position:0% +they look to just make sure they're not +getting to some of these effects because + + align:start position:0% +getting to some of these effects because + + + align:start position:0% +getting to some of these effects because +of some other sensory effects they could + + align:start position:0% +of some other sensory effects they could + + + align:start position:0% +of some other sensory effects they could +be it was important to figure that out + + align:start position:0% +be it was important to figure that out + + + align:start position:0% +be it was important to figure that out +these were really motor control + + align:start position:0% +these were really motor control + + + align:start position:0% +these were really motor control +effects and not due to sensation + + align:start position:0% + + + + align:start position:0% + +so again with a pretty complete lesion + + align:start position:0% +so again with a pretty complete lesion + + + align:start position:0% +so again with a pretty complete lesion +of the rubber spinal tract he's almost + + align:start position:0% +of the rubber spinal tract he's almost + + + align:start position:0% +of the rubber spinal tract he's almost +completely unable + + align:start position:0% + + + + align:start position:0% + +to move his limbs + + align:start position:0% + + + + align:start position:0% + +uh we'll have to try to + + align:start position:0% + + + + align:start position:0% + +see if we can get that working again + + align:start position:0% + + + + align:start position:0% + +it's still on video hit that + + align:start position:0% + + + + align:start position:0% + +there we are + + align:start position:0% +there we are + + + align:start position:0% +there we are +okay + + align:start position:0% + + + + align:start position:0% + +so the result + + align:start position:0% +so the result + + + align:start position:0% +so the result +is that we have they were able to + + align:start position:0% +is that we have they were able to + + + align:start position:0% +is that we have they were able to +separate two systems one for control of + + align:start position:0% +separate two systems one for control of + + + align:start position:0% +separate two systems one for control of +axial muscles and whole body movements + + align:start position:0% +axial muscles and whole body movements + + + align:start position:0% +axial muscles and whole body movements +the other for control of distal muscles + + align:start position:0% +the other for control of distal muscles + + + align:start position:0% +the other for control of distal muscles +and + + align:start position:0% +and + + + align:start position:0% +and +fractionated movements not just control + + align:start position:0% +fractionated movements not just control + + + align:start position:0% +fractionated movements not just control +the distal muscles but the ability to + + align:start position:0% +the distal muscles but the ability to + + + align:start position:0% +the distal muscles but the ability to +move individual digits + + align:start position:0% +move individual digits + + + align:start position:0% +move individual digits +something that + + align:start position:0% +something that + + + align:start position:0% +something that +we don't see in humans until they've + + align:start position:0% +we don't see in humans until they've + + + align:start position:0% +we don't see in humans until they've +developed + + align:start position:0% +developed + + + align:start position:0% +developed +in the salmon monkeys until there's a + + align:start position:0% +in the salmon monkeys until there's a + + + align:start position:0% +in the salmon monkeys until there's a +maturation + + align:start position:0% +maturation + + + align:start position:0% +maturation +of the + + align:start position:0% +of the + + + align:start position:0% +of the +connections between neocortex and motor + + align:start position:0% +connections between neocortex and motor + + + align:start position:0% +connections between neocortex and motor +neurons in the spinal enlargements + + align:start position:0% +neurons in the spinal enlargements + + + align:start position:0% +neurons in the spinal enlargements +okay and this just summarizes for you + + align:start position:0% +okay and this just summarizes for you + + + align:start position:0% +okay and this just summarizes for you +what you saw + + align:start position:0% +what you saw + + + align:start position:0% +what you saw +in the film okay the effects of + + align:start position:0% +in the film okay the effects of + + + align:start position:0% +in the film okay the effects of +paramidotomy + + align:start position:0% +paramidotomy + + + align:start position:0% +paramidotomy +the medial pathway lesion + + align:start position:0% +the medial pathway lesion + + + align:start position:0% +the medial pathway lesion +and the lateral hind brain + + align:start position:0% +and the lateral hind brain + + + align:start position:0% +and the lateral hind brain +okay + + align:start position:0% + + + + align:start position:0% + +now just a few more things on motor + + align:start position:0% +now just a few more things on motor + + + align:start position:0% +now just a few more things on motor +control if you look at a human + + align:start position:0% +control if you look at a human + + + align:start position:0% +control if you look at a human +who's lost + + align:start position:0% +who's lost + + + align:start position:0% +who's lost +control of his movements because of + + align:start position:0% +control of his movements because of + + + align:start position:0% +control of his movements because of +severance of descending pathways + + align:start position:0% +severance of descending pathways + + + align:start position:0% +severance of descending pathways +you might have spinal reflexes + + align:start position:0% +you might have spinal reflexes + + + align:start position:0% +you might have spinal reflexes +in fact the brain areas + + align:start position:0% +in fact the brain areas + + + align:start position:0% +in fact the brain areas +in the motor cortex + + align:start position:0% + + + + align:start position:0% + +will still be active if he's + + align:start position:0% +will still be active if he's + + + align:start position:0% +will still be active if he's +wanting to move + + align:start position:0% +wanting to move + + + align:start position:0% +wanting to move +so if you ask him try to move your hand + + align:start position:0% +so if you ask him try to move your hand + + + align:start position:0% +so if you ask him try to move your hand +nothing his hand doesn't move but in the + + align:start position:0% +nothing his hand doesn't move but in the + + + align:start position:0% +nothing his hand doesn't move but in the +imaging you'll see + + align:start position:0% +imaging you'll see + + + align:start position:0% +imaging you'll see +a hand area become active + + align:start position:0% +a hand area become active + + + align:start position:0% +a hand area become active +and these are functional imaging studies + + align:start position:0% +and these are functional imaging studies + + + align:start position:0% +and these are functional imaging studies +showing that + + align:start position:0% +showing that + + + align:start position:0% +showing that +this was a study just a couple years ago + + align:start position:0% + + + + align:start position:0% + +now does this help us understand other + + align:start position:0% +now does this help us understand other + + + align:start position:0% +now does this help us understand other +systems well if you look at the + + align:start position:0% +systems well if you look at the + + + align:start position:0% +systems well if you look at the +cerebellum you do see a related + + align:start position:0% +cerebellum you do see a related + + + align:start position:0% +cerebellum you do see a related +organization + + align:start position:0% +organization + + + align:start position:0% +organization +there's many aspects of cerebellum here + + align:start position:0% +there's many aspects of cerebellum here + + + align:start position:0% +there's many aspects of cerebellum here +we're not talking about + + align:start position:0% +we're not talking about + + + align:start position:0% +we're not talking about +but they're definitely medial and + + align:start position:0% +but they're definitely medial and + + + align:start position:0% +but they're definitely medial and +lateral systems and the lat the + + align:start position:0% +lateral systems and the lat the + + + align:start position:0% +lateral systems and the lat the +hemispheres which are huge in humans + + align:start position:0% +hemispheres which are huge in humans + + + align:start position:0% +hemispheres which are huge in humans +uh are definitely more concerned with + + align:start position:0% +uh are definitely more concerned with + + + align:start position:0% +uh are definitely more concerned with +distal muscle control they're concerned + + align:start position:0% +distal muscle control they're concerned + + + align:start position:0% +distal muscle control they're concerned +with other things too but + + align:start position:0% +with other things too but + + + align:start position:0% +with other things too but +it's only the most medial part of the + + align:start position:0% +it's only the most medial part of the + + + align:start position:0% +it's only the most medial part of the +cerebellum which is also the most + + align:start position:0% +cerebellum which is also the most + + + align:start position:0% +cerebellum which is also the most +ancient part remember the cerebellum + + align:start position:0% +ancient part remember the cerebellum + + + align:start position:0% +ancient part remember the cerebellum +develop seems to have evolved out of the + + align:start position:0% +develop seems to have evolved out of the + + + align:start position:0% +develop seems to have evolved out of the +vestibular system okay + + align:start position:0% +vestibular system okay + + + align:start position:0% +vestibular system okay +and the part + + align:start position:0% +and the part + + + align:start position:0% +and the part +the medial + + align:start position:0% +the medial + + + align:start position:0% +the medial +and caudal cerebellum that's connected + + align:start position:0% +and caudal cerebellum that's connected + + + align:start position:0% +and caudal cerebellum that's connected +to the vestibular system it affects + + align:start position:0% +to the vestibular system it affects + + + align:start position:0% +to the vestibular system it affects +spinal cord through the vestibular + + align:start position:0% +spinal cord through the vestibular + + + align:start position:0% +spinal cord through the vestibular +spinal tract and also connections to the + + align:start position:0% +spinal tract and also connections to the + + + align:start position:0% +spinal tract and also connections to the +reticular formation + + align:start position:0% + + + + align:start position:0% + +and it + + align:start position:0% +and it + + + align:start position:0% +and it +correspondingly + + align:start position:0% +correspondingly + + + align:start position:0% +correspondingly +to what we just saw + + align:start position:0% +to what we just saw + + + align:start position:0% +to what we just saw +its coordinates axial muscles whole body + + align:start position:0% +its coordinates axial muscles whole body + + + align:start position:0% +its coordinates axial muscles whole body +movements the lateral cerebellum + + align:start position:0% +movements the lateral cerebellum + + + align:start position:0% +movements the lateral cerebellum +and i mentioned here + + align:start position:0% +and i mentioned here + + + align:start position:0% +and i mentioned here +its outputs it has a + + align:start position:0% +its outputs it has a + + + align:start position:0% +its outputs it has a +name i don't require you to learn it + + align:start position:0% +name i don't require you to learn it + + + align:start position:0% +name i don't require you to learn it +here but it projects forward to the + + align:start position:0% +here but it projects forward to the + + + align:start position:0% +here but it projects forward to the +opposite hemisphere and also that + + align:start position:0% +opposite hemisphere and also that + + + align:start position:0% +opposite hemisphere and also that +pathway connects to the red nucleus then + + align:start position:0% +pathway connects to the red nucleus then + + + align:start position:0% +pathway connects to the red nucleus then +it goes to the primarily the vl of the + + align:start position:0% +it goes to the primarily the vl of the + + + align:start position:0% +it goes to the primarily the vl of the +thalamus + + align:start position:0% +thalamus + + + align:start position:0% +thalamus +goes to the which projects the motor + + align:start position:0% +goes to the which projects the motor + + + align:start position:0% +goes to the which projects the motor +cortex and very important for + + align:start position:0% +cortex and very important for + + + align:start position:0% +cortex and very important for +coordinating the timing of neocortical + + align:start position:0% +coordinating the timing of neocortical + + + align:start position:0% +coordinating the timing of neocortical +control movements + + align:start position:0% +control movements + + + align:start position:0% +control movements +if we get a lesion + + align:start position:0% +if we get a lesion + + + align:start position:0% +if we get a lesion +we can affect those things for example a + + align:start position:0% +we can affect those things for example a + + + align:start position:0% +we can affect those things for example a +lesion of the hemispheres that affect + + align:start position:0% +lesion of the hemispheres that affect + + + align:start position:0% +lesion of the hemispheres that affect +hand control + + align:start position:0% +hand control + + + align:start position:0% +hand control +when a hand in arm control if a person + + align:start position:0% +when a hand in arm control if a person + + + align:start position:0% +when a hand in arm control if a person +has a cerebellar lesion when he tries to + + align:start position:0% +has a cerebellar lesion when he tries to + + + align:start position:0% +has a cerebellar lesion when he tries to +reach you know he'll say he reaches out + + align:start position:0% +reach you know he'll say he reaches out + + + align:start position:0% +reach you know he'll say he reaches out +here for the stylist as he nears the + + align:start position:0% +here for the stylist as he nears the + + + align:start position:0% +here for the stylist as he nears the +stylus he starts he gets a bad dreamer + + align:start position:0% +stylus he starts he gets a bad dreamer + + + align:start position:0% +stylus he starts he gets a bad dreamer +it's called intention dreamer it happens + + align:start position:0% +it's called intention dreamer it happens + + + align:start position:0% +it's called intention dreamer it happens +when he's trying to do something he's + + align:start position:0% +when he's trying to do something he's + + + align:start position:0% +when he's trying to do something he's +trying to make a movement and he will + + align:start position:0% +trying to make a movement and he will + + + align:start position:0% +trying to make a movement and he will +shake okay he has poor control timing + + align:start position:0% +shake okay he has poor control timing + + + align:start position:0% +shake okay he has poor control timing +timing and + + align:start position:0% +timing and + + + align:start position:0% +timing and +gain now you do get recovery from + + align:start position:0% +gain now you do get recovery from + + + align:start position:0% +gain now you do get recovery from +cerebellar lesions but they take a long + + align:start position:0% +cerebellar lesions but they take a long + + + align:start position:0% +cerebellar lesions but they take a long +time and they coordinate it's not a + + align:start position:0% +time and they coordinate it's not a + + + align:start position:0% +time and they coordinate it's not a +complete recovery + + align:start position:0% +complete recovery + + + align:start position:0% +complete recovery +okay because other parts of the brain + + align:start position:0% +okay because other parts of the brain + + + align:start position:0% +okay because other parts of the brain +particularly parietal cortex + + align:start position:0% +particularly parietal cortex + + + align:start position:0% +particularly parietal cortex +can take over some of those functions + + align:start position:0% +can take over some of those functions + + + align:start position:0% +can take over some of those functions +now what about corpus triadum this has + + align:start position:0% +now what about corpus triadum this has + + + align:start position:0% +now what about corpus triadum this has +been much more complex and difficult to + + align:start position:0% +been much more complex and difficult to + + + align:start position:0% +been much more complex and difficult to +study + + align:start position:0% +study + + + align:start position:0% +study +but the main + + align:start position:0% +but the main + + + align:start position:0% +but the main +evidence we have of its important + + align:start position:0% +evidence we have of its important + + + align:start position:0% +evidence we have of its important +movement importance in movement control + + align:start position:0% +movement importance in movement control + + + align:start position:0% +movement importance in movement control +where the + + align:start position:0% +where the + + + align:start position:0% +where the +the dyskinesis of + + align:start position:0% +the dyskinesis of + + + align:start position:0% +the dyskinesis of +of basal ganglia + + align:start position:0% +of basal ganglia + + + align:start position:0% +of basal ganglia +pathologies so for example in + + align:start position:0% +pathologies so for example in + + + align:start position:0% +pathologies so for example in +huntington's disease + + align:start position:0% +huntington's disease + + + align:start position:0% +huntington's disease +the patient makes as the as the disease + + align:start position:0% +the patient makes as the as the disease + + + align:start position:0% +the patient makes as the as the disease +gets worse he makes involuntary writhing + + align:start position:0% +gets worse he makes involuntary writhing + + + align:start position:0% +gets worse he makes involuntary writhing +movements that sometimes are called + + align:start position:0% +movements that sometimes are called + + + align:start position:0% +movements that sometimes are called +choreoform because they look like + + align:start position:0% +choreoform because they look like + + + align:start position:0% +choreoform because they look like +they're dance movements + + align:start position:0% +they're dance movements + + + align:start position:0% +they're dance movements +korea means dancing + + align:start position:0% +korea means dancing + + + align:start position:0% +korea means dancing +okay and another pathology of the output + + align:start position:0% +okay and another pathology of the output + + + align:start position:0% +okay and another pathology of the output +circuitry of the corpus tree atom + + align:start position:0% +circuitry of the corpus tree atom + + + align:start position:0% +circuitry of the corpus tree atom +when part of that degenerates you can + + align:start position:0% +when part of that degenerates you can + + + align:start position:0% +when part of that degenerates you can +get people that when they try to move + + align:start position:0% +get people that when they try to move + + + align:start position:0% +get people that when they try to move +their arm move it in a ballistic way so + + align:start position:0% +their arm move it in a ballistic way so + + + align:start position:0% +their arm move it in a ballistic way so +they're flinging movements of the arm + + align:start position:0% +they're flinging movements of the arm + + + align:start position:0% +they're flinging movements of the arm +instead of smooth coordinated movements + + align:start position:0% +instead of smooth coordinated movements + + + align:start position:0% +instead of smooth coordinated movements +that's called ballisticus and hemi + + align:start position:0% +that's called ballisticus and hemi + + + align:start position:0% +that's called ballisticus and hemi +ballism is a if they have the problem + + align:start position:0% +ballism is a if they have the problem + + + align:start position:0% +ballism is a if they have the problem +the degeneration on one side of the + + align:start position:0% +the degeneration on one side of the + + + align:start position:0% +the degeneration on one side of the +output pathways in corpus triad and + + align:start position:0% +output pathways in corpus triad and + + + align:start position:0% +output pathways in corpus triad and +they'll develop that problem on only one + + align:start position:0% +they'll develop that problem on only one + + + align:start position:0% +they'll develop that problem on only one +side of the body + + align:start position:0% +side of the body + + + align:start position:0% +side of the body +the best known + + align:start position:0% +the best known + + + align:start position:0% +the best known +basal ganglia disease is parkinson's + + align:start position:0% +basal ganglia disease is parkinson's + + + align:start position:0% +basal ganglia disease is parkinson's +disease + + align:start position:0% +disease + + + align:start position:0% +disease +where + + align:start position:0% +where + + + align:start position:0% +where +they have a different kind of tremor + + align:start position:0% +they have a different kind of tremor + + + align:start position:0% +they have a different kind of tremor +when they're just sitting at rest they + + align:start position:0% +when they're just sitting at rest they + + + align:start position:0% +when they're just sitting at rest they +will shake many of you seen this many + + align:start position:0% +will shake many of you seen this many + + + align:start position:0% +will shake many of you seen this many +older people get + + align:start position:0% +older people get + + + align:start position:0% +older people get +at least some of this + + align:start position:0% +at least some of this + + + align:start position:0% +at least some of this +but it's a specific disease and when it + + align:start position:0% +but it's a specific disease and when it + + + align:start position:0% +but it's a specific disease and when it +strikes younger people it's particularly + + align:start position:0% +strikes younger people it's particularly + + + align:start position:0% +strikes younger people it's particularly +tragic + + align:start position:0% +tragic + + + align:start position:0% +tragic +they develop the resting creamer they + + align:start position:0% +they develop the resting creamer they + + + align:start position:0% +they develop the resting creamer they +become increasingly rigid their + + align:start position:0% +become increasingly rigid their + + + align:start position:0% +become increasingly rigid their +movements slow down + + align:start position:0% +movements slow down + + + align:start position:0% +movements slow down +and then they get a loss of emotional + + align:start position:0% +and then they get a loss of emotional + + + align:start position:0% +and then they get a loss of emotional +displays it begins to affect these + + align:start position:0% +displays it begins to affect these + + + align:start position:0% +displays it begins to affect these +control of these higher functions + + align:start position:0% +control of these higher functions + + + align:start position:0% +control of these higher functions +and it's correlated with loss of neurons + + align:start position:0% +and it's correlated with loss of neurons + + + align:start position:0% +and it's correlated with loss of neurons +in the substantia which is part of + + align:start position:0% +in the substantia which is part of + + + align:start position:0% +in the substantia which is part of +the midbrain + + align:start position:0% +the midbrain + + + align:start position:0% +the midbrain +that contain dopamine and they project + + align:start position:0% +that contain dopamine and they project + + + align:start position:0% +that contain dopamine and they project +forward to the corpus tree atom and as + + align:start position:0% +forward to the corpus tree atom and as + + + align:start position:0% +forward to the corpus tree atom and as +dopamine becomes depleted you begin to + + align:start position:0% +dopamine becomes depleted you begin to + + + align:start position:0% +dopamine becomes depleted you begin to +get these symptoms + + align:start position:0% +get these symptoms + + + align:start position:0% +get these symptoms +okay and this is what it shows + + align:start position:0% +okay and this is what it shows + + + align:start position:0% +okay and this is what it shows +in here + + align:start position:0% +in here + + + align:start position:0% +in here +in dopamine receptors increase with the + + align:start position:0% +in dopamine receptors increase with the + + + align:start position:0% +in dopamine receptors increase with the +loss of axons to come in compensate + + align:start position:0% +loss of axons to come in compensate + + + align:start position:0% +loss of axons to come in compensate +compensation for the loss + + align:start position:0% +compensation for the loss + + + align:start position:0% +compensation for the loss +but then with more and more neurons lost + + align:start position:0% +but then with more and more neurons lost + + + align:start position:0% +but then with more and more neurons lost +and here you see the loss of pigmented + + align:start position:0% +and here you see the loss of pigmented + + + align:start position:0% +and here you see the loss of pigmented +neurons in the + + align:start position:0% +neurons in the + + + align:start position:0% +neurons in the +finally the receptors go down too and + + align:start position:0% +finally the receptors go down too and + + + align:start position:0% +finally the receptors go down too and +the parkinson's symptoms + + align:start position:0% +the parkinson's symptoms + + + align:start position:0% +the parkinson's symptoms +appear late after there's been a lot of + + align:start position:0% +appear late after there's been a lot of + + + align:start position:0% +appear late after there's been a lot of +loss as i mentioned before you these + + align:start position:0% +loss as i mentioned before you these + + + align:start position:0% +loss as i mentioned before you these +slow + + align:start position:0% +slow + + + align:start position:0% +slow +pathologies slower slowly at developing + + align:start position:0% +pathologies slower slowly at developing + + + align:start position:0% +pathologies slower slowly at developing +lesions + + align:start position:0% +lesions + + + align:start position:0% +lesions +often the the + + align:start position:0% +often the the + + + align:start position:0% +often the the +behavioral change is seen late okay + + align:start position:0% + + + + align:start position:0% + +and they've developed ways of trying to + + align:start position:0% +and they've developed ways of trying to + + + align:start position:0% +and they've developed ways of trying to +replace the dopamine in the striatum + + align:start position:0% +replace the dopamine in the striatum + + + align:start position:0% +replace the dopamine in the striatum +and then i've mentioned that implicit + + align:start position:0% +and then i've mentioned that implicit + + + align:start position:0% +and then i've mentioned that implicit +learning + + align:start position:0% +learning + + + align:start position:0% +learning +especially the word at work and graybill + + align:start position:0% +especially the word at work and graybill + + + align:start position:0% +especially the word at work and graybill +and other people working on this they + + align:start position:0% +and other people working on this they + + + align:start position:0% +and other people working on this they +find that somehow there's an interaction + + align:start position:0% +find that somehow there's an interaction + + + align:start position:0% +find that somehow there's an interaction +in the corpus triadum + + align:start position:0% +in the corpus triadum + + + align:start position:0% +in the corpus triadum +when we learn habits + + align:start position:0% +when we learn habits + + + align:start position:0% +when we learn habits +reward and reinforcement for movements + + align:start position:0% +reward and reinforcement for movements + + + align:start position:0% +reward and reinforcement for movements +seems to act in the corpus triad and + + align:start position:0% +seems to act in the corpus triad and + + + align:start position:0% +seems to act in the corpus triad and +alter the connections + + align:start position:0% +alter the connections + + + align:start position:0% +alter the connections +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and we know of course that over time + + align:start position:0% +and we know of course that over time + + + align:start position:0% +and we know of course that over time +things movements that were initially + + align:start position:0% +things movements that were initially + + + align:start position:0% +things movements that were initially +voluntary become habitual + + align:start position:0% +voluntary become habitual + + + align:start position:0% +voluntary become habitual +and that always seems to involve the + + align:start position:0% +and that always seems to involve the + + + align:start position:0% +and that always seems to involve the +corpus triadum and that's all we have + + align:start position:0% +corpus triadum and that's all we have + + + align:start position:0% +corpus triadum and that's all we have +time for i will \ No newline at end of file diff --git a/9RZa3zBruVA.txt b/9RZa3zBruVA.txt new file mode 100644 index 0000000000000000000000000000000000000000..9bdc97a22f2c3a34f1c4a923d5f10aa0bdf432bc --- /dev/null +++ b/9RZa3zBruVA.txt @@ -0,0 +1,1691 @@ +align:start position:0% + +so my philosophy of teaching Chinese uh + + align:start position:0% +so my philosophy of teaching Chinese uh + + + align:start position:0% +so my philosophy of teaching Chinese uh +well it's very interesting uh process + + align:start position:0% +well it's very interesting uh process + + + align:start position:0% +well it's very interesting uh process +because when I started I knew one method + + align:start position:0% +because when I started I knew one method + + + align:start position:0% +because when I started I knew one method +and I thought that was the best in the + + align:start position:0% +and I thought that was the best in the + + + align:start position:0% +and I thought that was the best in the +world uh to do drill instruct you know + + align:start position:0% +world uh to do drill instruct you know + + + align:start position:0% +world uh to do drill instruct you know +like drill the students all the time + + align:start position:0% +like drill the students all the time + + + align:start position:0% +like drill the students all the time +make them repeat but throughout the + + align:start position:0% +make them repeat but throughout the + + + align:start position:0% +make them repeat but throughout the +years I realized uh they can say certain + + align:start position:0% +years I realized uh they can say certain + + + align:start position:0% +years I realized uh they can say certain +things but they could not have a + + align:start position:0% +things but they could not have a + + + align:start position:0% +things but they could not have a +conversation so they're they can do well + + align:start position:0% +conversation so they're they can do well + + + align:start position:0% +conversation so they're they can do well +and test that doesn't mean they can go + + align:start position:0% +and test that doesn't mean they can go + + + align:start position:0% +and test that doesn't mean they can go +out have a conversation so I think I've + + align:start position:0% +out have a conversation so I think I've + + + align:start position:0% +out have a conversation so I think I've +evolved and I right now I think the main + + align:start position:0% +evolved and I right now I think the main + + + align:start position:0% +evolved and I right now I think the main +uh Philosophy for me is to have a + + align:start position:0% +uh Philosophy for me is to have a + + + align:start position:0% +uh Philosophy for me is to have a +welcoming + + align:start position:0% +welcoming + + + align:start position:0% +welcoming +environment to help student to speak the + + align:start position:0% +environment to help student to speak the + + + align:start position:0% +environment to help student to speak the +language not to talk about the + + align:start position:0% +language not to talk about the + + + align:start position:0% +language not to talk about the +language um so that's my current f + + align:start position:0% +language um so that's my current f + + + align:start position:0% +language um so that's my current f +philosophical idea so everything I do is + + align:start position:0% +philosophical idea so everything I do is + + + align:start position:0% +philosophical idea so everything I do is +to uh carry this out and create + + align:start position:0% +to uh carry this out and create + + + align:start position:0% +to uh carry this out and create +environment for this + + align:start position:0% +environment for this + + + align:start position:0% +environment for this +philosophy so um so I did a lot um right + + align:start position:0% +philosophy so um so I did a lot um right + + + align:start position:0% +philosophy so um so I did a lot um right +for the past few years I start started + + align:start position:0% +for the past few years I start started + + + align:start position:0% +for the past few years I start started +changing and I did a lot um they said a + + align:start position:0% +changing and I did a lot um they said a + + + align:start position:0% +changing and I did a lot um they said a +scaold scaffolding uh instructions and + + align:start position:0% +scaold scaffolding uh instructions and + + + align:start position:0% +scaold scaffolding uh instructions and +very student centered instruction I used + + align:start position:0% +very student centered instruction I used + + + align:start position:0% +very student centered instruction I used +used to be very teacher center it's very + + align:start position:0% +used to be very teacher center it's very + + + align:start position:0% +used to be very teacher center it's very +efficient don't get me wrong it's very + + align:start position:0% +efficient don't get me wrong it's very + + + align:start position:0% +efficient don't get me wrong it's very +effective too you keep the uh you kept + + align:start position:0% +effective too you keep the uh you kept + + + align:start position:0% +effective too you keep the uh you kept +the students on their toes they have to + + align:start position:0% +the students on their toes they have to + + + align:start position:0% +the students on their toes they have to +you know gge back right away but really + + align:start position:0% +you know gge back right away but really + + + align:start position:0% +you know gge back right away but really +and I got this evaluation one year they + + align:start position:0% +and I got this evaluation one year they + + + align:start position:0% +and I got this evaluation one year they +say oh the teacher is incredible she's + + align:start position:0% +say oh the teacher is incredible she's + + + align:start position:0% +say oh the teacher is incredible she's +so good but I wish I can learn how to + + align:start position:0% +so good but I wish I can learn how to + + + align:start position:0% +so good but I wish I can learn how to +speak I was like what does that mean and + + align:start position:0% +speak I was like what does that mean and + + + align:start position:0% +speak I was like what does that mean and +you you spoke well and I realized he was + + align:start position:0% +you you spoke well and I realized he was + + + align:start position:0% +you you spoke well and I realized he was +doing the drill pattern he can say so + + align:start position:0% +doing the drill pattern he can say so + + + align:start position:0% +doing the drill pattern he can say so +certain sentence when I asked him to say + + align:start position:0% +certain sentence when I asked him to say + + + align:start position:0% +certain sentence when I asked him to say +it and repeat after me but have him to + + align:start position:0% +it and repeat after me but have him to + + + align:start position:0% +it and repeat after me but have him to +have a natural conversation was really + + align:start position:0% +have a natural conversation was really + + + align:start position:0% +have a natural conversation was really +difficult so that dawned on me I start + + align:start position:0% +difficult so that dawned on me I start + + + align:start position:0% +difficult so that dawned on me I start +changing and I try to uh attend + + align:start position:0% +changing and I try to uh attend + + + align:start position:0% +changing and I try to uh attend +conference and workshop not related to + + align:start position:0% +conference and workshop not related to + + + align:start position:0% +conference and workshop not related to +just teaching Chinese more like um how + + align:start position:0% +just teaching Chinese more like um how + + + align:start position:0% +just teaching Chinese more like um how +to educate people more education and how + + align:start position:0% +to educate people more education and how + + + align:start position:0% +to educate people more education and how +to uh create environment for all student + + align:start position:0% +to uh create environment for all student + + + align:start position:0% +to uh create environment for all student +feel safe so I adapt those philosophy in + + align:start position:0% +feel safe so I adapt those philosophy in + + + align:start position:0% +feel safe so I adapt those philosophy in +my course to so my My Philosophy is a + + align:start position:0% +my course to so my My Philosophy is a + + + align:start position:0% +my course to so my My Philosophy is a +weling welcoming environment that means + + align:start position:0% +weling welcoming environment that means + + + align:start position:0% +weling welcoming environment that means +um building a community for student feel + + align:start position:0% +um building a community for student feel + + + align:start position:0% +um building a community for student feel +very safe to speak the language in this + + align:start position:0% +very safe to speak the language in this + + + align:start position:0% +very safe to speak the language in this +community they're not afraid to make + + align:start position:0% +community they're not afraid to make + + + align:start position:0% +community they're not afraid to make +mistakes and they're they always + + align:start position:0% +mistakes and they're they always + + + align:start position:0% +mistakes and they're they always +volunteer uh their opinions that's my + + align:start position:0% +volunteer uh their opinions that's my + + + align:start position:0% +volunteer uh their opinions that's my +goal the first + + align:start position:0% +goal the first + + + align:start position:0% +goal the first +step + + align:start position:0% +step + + + align:start position:0% +step +uh as I said My Philosophy is to create + + align:start position:0% +uh as I said My Philosophy is to create + + + align:start position:0% +uh as I said My Philosophy is to create +a welcoming environment to build a + + align:start position:0% +a welcoming environment to build a + + + align:start position:0% +a welcoming environment to build a +community so for example I umum recently + + align:start position:0% +community so for example I umum recently + + + align:start position:0% +community so for example I umum recently +uh two years ago I went to a workshop + + align:start position:0% +uh two years ago I went to a workshop + + + align:start position:0% +uh two years ago I went to a workshop +called responsive classroom uh + + align:start position:0% +called responsive classroom uh + + + align:start position:0% +called responsive classroom uh +responsive uh responsive classrooms + + align:start position:0% +responsive uh responsive classrooms + + + align:start position:0% +responsive uh responsive classrooms +geared to a k212 is talking about it's + + align:start position:0% +geared to a k212 is talking about it's + + + align:start position:0% +geared to a k212 is talking about it's +more it's more treating the younger kids + + align:start position:0% +more it's more treating the younger kids + + + align:start position:0% +more it's more treating the younger kids +try to get rid of the behavior issue I + + align:start position:0% +try to get rid of the behavior issue I + + + align:start position:0% +try to get rid of the behavior issue I +don't need to do it in my classroom but + + align:start position:0% +don't need to do it in my classroom but + + + align:start position:0% +don't need to do it in my classroom but +I think strategy there is actually works + + align:start position:0% +I think strategy there is actually works + + + align:start position:0% +I think strategy there is actually works +first thing they do is building + + align:start position:0% +first thing they do is building + + + align:start position:0% +first thing they do is building +community so for example I do the first + + align:start position:0% +community so for example I do the first + + + align:start position:0% +community so for example I do the first +week of my course and these are harage + + align:start position:0% +week of my course and these are harage + + + align:start position:0% +week of my course and these are harage +to learn they already know how to speak + + align:start position:0% +to learn they already know how to speak + + + align:start position:0% +to learn they already know how to speak +but they are so embarrassed with them + + align:start position:0% +but they are so embarrassed with them + + + align:start position:0% +but they are so embarrassed with them +because they will tell me my + + align:start position:0% +because they will tell me my + + + align:start position:0% +because they will tell me my +pronunciation is bad I don't speak to + + align:start position:0% +pronunciation is bad I don't speak to + + + align:start position:0% +pronunciation is bad I don't speak to +anybody else only to my parents I don't + + align:start position:0% +anybody else only to my parents I don't + + + align:start position:0% +anybody else only to my parents I don't +want to speak in the classroom so + + align:start position:0% +want to speak in the classroom so + + + align:start position:0% +want to speak in the classroom so +basically I do the greeting the very + + align:start position:0% +basically I do the greeting the very + + + align:start position:0% +basically I do the greeting the very +easy things they're comfortable with for + + align:start position:0% +easy things they're comfortable with for + + + align:start position:0% +easy things they're comfortable with for +instance they talk about their name name + + align:start position:0% +instance they talk about their name name + + + align:start position:0% +instance they talk about their name name +whe they're major they can all speak + + align:start position:0% +whe they're major they can all speak + + + align:start position:0% +whe they're major they can all speak +these you know in Chinese so what I do + + align:start position:0% +these you know in Chinese so what I do + + + align:start position:0% +these you know in Chinese so what I do +is the first day like that and then + + align:start position:0% +is the first day like that and then + + + align:start position:0% +is the first day like that and then +started I build into a routine so every + + align:start position:0% +started I build into a routine so every + + + align:start position:0% +started I build into a routine so every +class I spend five to 10 minutes every + + align:start position:0% +class I spend five to 10 minutes every + + + align:start position:0% +class I spend five to 10 minutes every +day we call G every class not every day + + align:start position:0% +day we call G every class not every day + + + align:start position:0% +day we call G every class not every day +we don't have a everyday class called + + align:start position:0% +we don't have a everyday class called + + + align:start position:0% +we don't have a everyday class called +greeting basically you I ask everybody + + align:start position:0% +greeting basically you I ask everybody + + + align:start position:0% +greeting basically you I ask everybody +to write their name on a car so I + + align:start position:0% +to write their name on a car so I + + + align:start position:0% +to write their name on a car so I +collect the car I put a car in the + + align:start position:0% +collect the car I put a car in the + + + align:start position:0% +collect the car I put a car in the +middle of the classroom so one student I + + align:start position:0% +middle of the classroom so one student I + + + align:start position:0% +middle of the classroom so one student I +will start because I need to to model + + align:start position:0% +will start because I need to to model + + + align:start position:0% +will start because I need to to model +what it means so I will pick up a + + align:start position:0% +what it means so I will pick up a + + + align:start position:0% +what it means so I will pick up a +students's c for instance I say oh Sarah + + align:start position:0% +students's c for instance I say oh Sarah + + + align:start position:0% +students's c for instance I say oh Sarah +Leen okay and I call her in her Chinese + + align:start position:0% +Leen okay and I call her in her Chinese + + + align:start position:0% +Leen okay and I call her in her Chinese +name and I would start saying how are + + align:start position:0% +name and I would start saying how are + + + align:start position:0% +name and I would start saying how are +you today you know what did you do last + + align:start position:0% +you today you know what did you do last + + + align:start position:0% +you today you know what did you do last +night stuff like that daily life things + + align:start position:0% +night stuff like that daily life things + + + align:start position:0% +night stuff like that daily life things +and then I asked the student did you see + + align:start position:0% +and then I asked the student did you see + + + align:start position:0% +and then I asked the student did you see +what I did so follow my model and come + + align:start position:0% +what I did so follow my model and come + + + align:start position:0% +what I did so follow my model and come +here pick up car greet your classmates + + align:start position:0% +here pick up car greet your classmates + + + align:start position:0% +here pick up car greet your classmates +so every day I do this uh I think after + + align:start position:0% +so every day I do this uh I think after + + + align:start position:0% +so every day I do this uh I think after +two weeks everybody knows everybody's + + align:start position:0% +two weeks everybody knows everybody's + + + align:start position:0% +two weeks everybody knows everybody's +name + + align:start position:0% +name + + + align:start position:0% +name +and while greeting this is not just + + align:start position:0% +and while greeting this is not just + + + align:start position:0% +and while greeting this is not just +simple greeting because you have a + + align:start position:0% +simple greeting because you have a + + + align:start position:0% +simple greeting because you have a +natural conversation when you say oh I + + align:start position:0% +natural conversation when you say oh I + + + align:start position:0% +natural conversation when you say oh I +went to bed really late last night and + + align:start position:0% +went to bed really late last night and + + + align:start position:0% +went to bed really late last night and +people were say why you know that so so + + align:start position:0% +people were say why you know that so so + + + align:start position:0% +people were say why you know that so so +I started very structure for instance + + align:start position:0% +I started very structure for instance + + + align:start position:0% +I started very structure for instance +just everybody's just say very limited + + align:start position:0% +just everybody's just say very limited + + + align:start position:0% +just everybody's just say very limited +things and then I will say okay so Sarah + + align:start position:0% +things and then I will say okay so Sarah + + + align:start position:0% +things and then I will say okay so Sarah +say she went to bed really late last + + align:start position:0% +say she went to bed really late last + + + align:start position:0% +say she went to bed really late last +night do you guys want to know why you + + align:start position:0% +night do you guys want to know why you + + + align:start position:0% +night do you guys want to know why you +know all in Chinese so they will start + + align:start position:0% +know all in Chinese so they will start + + + align:start position:0% +know all in Chinese so they will start +asking so I buil on that difficulty so + + align:start position:0% +asking so I buil on that difficulty so + + + align:start position:0% +asking so I buil on that difficulty so +um the weekend the Monday class is + + align:start position:0% +um the weekend the Monday class is + + + align:start position:0% +um the weekend the Monday class is +really fun they love it because you can + + align:start position:0% +really fun they love it because you can + + + align:start position:0% +really fun they love it because you can +talk about your weekend so kids here + + align:start position:0% +talk about your weekend so kids here + + + align:start position:0% +talk about your weekend so kids here +they did all kinds of activity during + + align:start position:0% +they did all kinds of activity during + + + align:start position:0% +they did all kinds of activity during +the weekend so they're so interested in + + align:start position:0% +the weekend so they're so interested in + + + align:start position:0% +the weekend so they're so interested in +finding out what their classmate did + + align:start position:0% +finding out what their classmate did + + + align:start position:0% +finding out what their classmate did +because they might not know each other + + align:start position:0% +because they might not know each other + + + align:start position:0% +because they might not know each other +or some took classes together so they + + align:start position:0% +or some took classes together so they + + + align:start position:0% +or some took classes together so they +were complain same course together in + + align:start position:0% +were complain same course together in + + + align:start position:0% +were complain same course together in +the classroom many teachers probably + + align:start position:0% +the classroom many teachers probably + + + align:start position:0% +the classroom many teachers probably +think it's a waste of time it's you know + + align:start position:0% +think it's a waste of time it's you know + + + align:start position:0% +think it's a waste of time it's you know +really you know why are you talking + + align:start position:0% +really you know why are you talking + + + align:start position:0% +really you know why are you talking +about that but I think it's is through + + align:start position:0% +about that but I think it's is through + + + align:start position:0% +about that but I think it's is through +this you build a community so the moment + + align:start position:0% +this you build a community so the moment + + + align:start position:0% +this you build a community so the moment +they walk into the classroom after one + + align:start position:0% +they walk into the classroom after one + + + align:start position:0% +they walk into the classroom after one +month they're this the the you know they + + align:start position:0% +month they're this the the you know they + + + align:start position:0% +month they're this the the you know they +could have a test before the Chinese + + align:start position:0% +could have a test before the Chinese + + + align:start position:0% +could have a test before the Chinese +class the moment they walk into because + + align:start position:0% +class the moment they walk into because + + + align:start position:0% +class the moment they walk into because +of this greeting rituals they have to + + align:start position:0% +of this greeting rituals they have to + + + align:start position:0% +of this greeting rituals they have to +switch their gear into speaking Chinese + + align:start position:0% +switch their gear into speaking Chinese + + + align:start position:0% +switch their gear into speaking Chinese +right + + align:start position:0% +right + + + align:start position:0% +right +away and they because you're you're + + align:start position:0% +away and they because you're you're + + + align:start position:0% +away and they because you're you're +having a conversation so you really need + + align:start position:0% +having a conversation so you really need + + + align:start position:0% +having a conversation so you really need +to engage your classmates so that what I + + align:start position:0% +to engage your classmates so that what I + + + align:start position:0% +to engage your classmates so that what I +mean building a community they feel so + + align:start position:0% +mean building a community they feel so + + + align:start position:0% +mean building a community they feel so +freely can talk about anything they + + align:start position:0% +freely can talk about anything they + + + align:start position:0% +freely can talk about anything they +could and they don't know the words they + + align:start position:0% +could and they don't know the words they + + + align:start position:0% +could and they don't know the words they +will ask me how do you say this you know + + align:start position:0% +will ask me how do you say this you know + + + align:start position:0% +will ask me how do you say this you know +this is what I'm doing right now it's + + align:start position:0% +this is what I'm doing right now it's + + + align:start position:0% +this is what I'm doing right now it's +really blah blah blah so and people + + align:start position:0% +really blah blah blah so and people + + + align:start position:0% +really blah blah blah so and people +really want to find out and I add + + align:start position:0% +really want to find out and I add + + + align:start position:0% +really want to find out and I add +another component after a few weeks um + + align:start position:0% +another component after a few weeks um + + + align:start position:0% +another component after a few weeks um +is to by the time now they already know + + align:start position:0% +is to by the time now they already know + + + align:start position:0% +is to by the time now they already know +each other's name so I like to every + + align:start position:0% +each other's name so I like to every + + + align:start position:0% +each other's name so I like to every +lesson I ask them to write an essay I + + align:start position:0% +lesson I ask them to write an essay I + + + align:start position:0% +lesson I ask them to write an essay I +give them a topic to write an essay so I + + align:start position:0% +give them a topic to write an essay so I + + + align:start position:0% +give them a topic to write an essay so I +will ask them for instance I'll say um + + align:start position:0% +will ask them for instance I'll say um + + + align:start position:0% +will ask them for instance I'll say um +we talk about uh family so our topic is + + align:start position:0% +we talk about uh family so our topic is + + + align:start position:0% +we talk about uh family so our topic is +Chinese family so I want them to go home + + align:start position:0% +Chinese family so I want them to go home + + + align:start position:0% +Chinese family so I want them to go home +to write about uh maybe a Italian family + + align:start position:0% +to write about uh maybe a Italian family + + + align:start position:0% +to write about uh maybe a Italian family +or Spanish family so the structure model + + align:start position:0% +or Spanish family so the structure model + + + align:start position:0% +or Spanish family so the structure model +on the textbook so nobody knows what + + align:start position:0% +on the textbook so nobody knows what + + + align:start position:0% +on the textbook so nobody knows what +other students were writing about right + + align:start position:0% +other students were writing about right + + + align:start position:0% +other students were writing about right +so this time we call sharing so this + + align:start position:0% +so this time we call sharing so this + + + align:start position:0% +so this time we call sharing so this +sharing part is talk about your what did + + align:start position:0% +sharing part is talk about your what did + + + align:start position:0% +sharing part is talk about your what did +you write right so some students oh I I + + align:start position:0% +you write right so some students oh I I + + + align:start position:0% +you write right so some students oh I I +wrote about Spanish family and I said + + align:start position:0% +wrote about Spanish family and I said + + + align:start position:0% +wrote about Spanish family and I said +what was that tell us not just the title + + align:start position:0% +what was that tell us not just the title + + + align:start position:0% +what was that tell us not just the title +what's the content about so they talk + + align:start position:0% +what's the content about so they talk + + + align:start position:0% +what's the content about so they talk +about everybody has a chance to talk + + align:start position:0% +about everybody has a chance to talk + + + align:start position:0% +about everybody has a chance to talk +about quickly and then I said oh this is + + align:start position:0% +about quickly and then I said oh this is + + + align:start position:0% +about quickly and then I said oh this is +very interesting so so student will you + + align:start position:0% +very interesting so so student will you + + + align:start position:0% +very interesting so so student will you +know automat automatically naturally + + align:start position:0% +know automat automatically naturally + + + align:start position:0% +know automat automatically naturally +just has why do you pick this topic it's + + align:start position:0% +just has why do you pick this topic it's + + + align:start position:0% +just has why do you pick this topic it's +so did you know any Spanish people you + + align:start position:0% +so did you know any Spanish people you + + + align:start position:0% +so did you know any Spanish people you +know so the natural conversation just + + align:start position:0% +know so the natural conversation just + + + align:start position:0% +know so the natural conversation just +flow so it get into a routine so every + + align:start position:0% +flow so it get into a routine so every + + + align:start position:0% +flow so it get into a routine so every +time they come to my classroom they know + + align:start position:0% +time they come to my classroom they know + + + align:start position:0% +time they come to my classroom they know +there should speak chines and they + + align:start position:0% +there should speak chines and they + + + align:start position:0% +there should speak chines and they +should talk about their life and that's + + align:start position:0% +should talk about their life and that's + + + align:start position:0% +should talk about their life and that's +what they're good at they cannot talk + + align:start position:0% +what they're good at they cannot talk + + + align:start position:0% +what they're good at they cannot talk +about politics they cannot talk about uh + + align:start position:0% +about politics they cannot talk about uh + + + align:start position:0% +about politics they cannot talk about uh +history but they can talk about + + align:start position:0% +history but they can talk about + + + align:start position:0% +history but they can talk about +themselves and so to make them um the + + align:start position:0% +themselves and so to make them um the + + + align:start position:0% +themselves and so to make them um the +Ora proficiency higher and they can + + align:start position:0% +Ora proficiency higher and they can + + + align:start position:0% +Ora proficiency higher and they can +speak uh much better as remember there's + + align:start position:0% +speak uh much better as remember there's + + + align:start position:0% +speak uh much better as remember there's +one student after the + + align:start position:0% +one student after the + + + align:start position:0% +one student after the +Thanksgiving she came back she was so + + align:start position:0% +Thanksgiving she came back she was so + + + align:start position:0% +Thanksgiving she came back she was so +excited she + + align:start position:0% +excited she + + + align:start position:0% +excited she +said oh um L that's how they address me + + align:start position:0% +said oh um L that's how they address me + + + align:start position:0% +said oh um L that's how they address me +as teacher and he said you know I um I + + align:start position:0% +as teacher and he said you know I um I + + + align:start position:0% +as teacher and he said you know I um I +my father had this uh friend and I + + align:start position:0% +my father had this uh friend and I + + + align:start position:0% +my father had this uh friend and I +always call him Uncle he's from China he + + align:start position:0% +always call him Uncle he's from China he + + + align:start position:0% +always call him Uncle he's from China he +doesn't speak any English so I met him + + align:start position:0% +doesn't speak any English so I met him + + + align:start position:0% +doesn't speak any English so I met him +in New York and when it was September I + + align:start position:0% +in New York and when it was September I + + + align:start position:0% +in New York and when it was September I +cannot communicate with him at all so + + align:start position:0% +cannot communicate with him at all so + + + align:start position:0% +cannot communicate with him at all so +during the Thanksgiving my home is so + + align:start position:0% +during the Thanksgiving my home is so + + + align:start position:0% +during the Thanksgiving my home is so +far away so I went to my uncle's place + + align:start position:0% +far away so I went to my uncle's place + + + align:start position:0% +far away so I went to my uncle's place +and I can talk to him and he kept saying + + align:start position:0% +and I can talk to him and he kept saying + + + align:start position:0% +and I can talk to him and he kept saying +that my Chinese improve and he said oh + + align:start position:0% +that my Chinese improve and he said oh + + + align:start position:0% +that my Chinese improve and he said oh +my God it's only two months I can't + + align:start position:0% +my God it's only two months I can't + + + align:start position:0% +my God it's only two months I can't +believe I can speak the most Chinese + + align:start position:0% +believe I can speak the most Chinese + + + align:start position:0% +believe I can speak the most Chinese +even though I speak Chinese with my + + align:start position:0% +even though I speak Chinese with my + + + align:start position:0% +even though I speak Chinese with my +parents I can never speak to anybody and + + align:start position:0% +parents I can never speak to anybody and + + + align:start position:0% +parents I can never speak to anybody and +she just came by so excit you know so + + align:start position:0% +she just came by so excit you know so + + + align:start position:0% +she just came by so excit you know so +excited and I so I feel great so I know + + align:start position:0% +excited and I so I feel great so I know + + + align:start position:0% +excited and I so I feel great so I know +it worked yeah because to her talking + + align:start position:0% +it worked yeah because to her talking + + + align:start position:0% +it worked yeah because to her talking +speaking in Chinese doesn't have to be + + align:start position:0% +speaking in Chinese doesn't have to be + + + align:start position:0% +speaking in Chinese doesn't have to be +something she to think about you know + + align:start position:0% +something she to think about you know + + + align:start position:0% +something she to think about you know +how do I come up with the first sentence + + align:start position:0% +how do I come up with the first sentence + + + align:start position:0% +how do I come up with the first sentence +anymore because she does that in her in + + align:start position:0% +anymore because she does that in her in + + + align:start position:0% +anymore because she does that in her in +our class every time so it's very + + align:start position:0% +our class every time so it's very + + + align:start position:0% +our class every time so it's very +natural for her and plus she's you know + + align:start position:0% +natural for her and plus she's you know + + + align:start position:0% +natural for her and plus she's you know +she actually knows Chinese because her + + align:start position:0% +she actually knows Chinese because her + + + align:start position:0% +she actually knows Chinese because her +background so she crossed the barrier be + + align:start position:0% +background so she crossed the barrier be + + + align:start position:0% +background so she crossed the barrier be +able to speak to other people which is + + align:start position:0% +able to speak to other people which is + + + align:start position:0% +able to speak to other people which is +fantastic \ No newline at end of file diff --git a/9yfcqI-lEj0.txt b/9yfcqI-lEj0.txt new file mode 100644 index 0000000000000000000000000000000000000000..301f5d07f00258b227a4bf0c9fbac83bc4e02d36 --- /dev/null +++ b/9yfcqI-lEj0.txt @@ -0,0 +1,10845 @@ +align:start position:0% + +means you had the states switched yes + + align:start position:0% +means you had the states switched yes + + + align:start position:0% +means you had the states switched yes +that cut you you meant the composition + + align:start position:0% +that cut you you meant the composition + + + align:start position:0% +that cut you you meant the composition +of states does that mean the the basis + + align:start position:0% +of states does that mean the the basis + + + align:start position:0% +of states does that mean the the basis +states that go to form the the the the + + align:start position:0% +states that go to form the the the the + + + align:start position:0% +states that go to form the the the the +states that make up those curves switch + + align:start position:0% +states that make up those curves switch + + + align:start position:0% +states that make up those curves switch +is that what you're saying yeah um I + + align:start position:0% +is that what you're saying yeah um I + + + align:start position:0% +is that what you're saying yeah um I +mean you can so + + align:start position:0% +mean you can so + + + align:start position:0% +mean you can so +let's uh when you have a weekly avoided + + align:start position:0% +let's uh when you have a weekly avoided + + + align:start position:0% +let's uh when you have a weekly avoided +Crossing you get this kind of a a + + align:start position:0% +Crossing you get this kind of a a + + + align:start position:0% +Crossing you get this kind of a a +behavior and so up in here + + align:start position:0% +behavior and so up in here + + + align:start position:0% +behavior and so up in here +this would be a uh an electronic state + + align:start position:0% +this would be a uh an electronic state + + + align:start position:0% +this would be a uh an electronic state +has an electronic + + align:start position:0% +has an electronic + + + align:start position:0% +has an electronic +configuration which is the same as the + + align:start position:0% +configuration which is the same as the + + + align:start position:0% +configuration which is the same as the +or similar to the electronic + + align:start position:0% +or similar to the electronic + + + align:start position:0% +or similar to the electronic +configuration down here okay and so uh + + align:start position:0% +configuration down here okay and so uh + + + align:start position:0% +configuration down here okay and so uh +what happens is you have a mixture you + + align:start position:0% +what happens is you have a mixture you + + + align:start position:0% +what happens is you have a mixture you +have say configuration number one + + align:start position:0% +have say configuration number one + + + align:start position:0% +have say configuration number one +configuration number two and near here + + align:start position:0% +configuration number two and near here + + + align:start position:0% +configuration number two and near here +all of a sudden uh you go from almost + + align:start position:0% +all of a sudden uh you go from almost + + + align:start position:0% +all of a sudden uh you go from almost +pure configuration 2 to almost pure + + align:start position:0% +pure configuration 2 to almost pure + + + align:start position:0% +pure configuration 2 to almost pure +configuration one and right here you + + align:start position:0% +configuration one and right here you + + + align:start position:0% +configuration one and right here you +have a 50/50 + + align:start position:0% +have a 50/50 + + + align:start position:0% +have a 50/50 +mixture and so the electronic character + + align:start position:0% +mixture and so the electronic character + + + align:start position:0% +mixture and so the electronic character +is hardly changing at all until right + + align:start position:0% +is hardly changing at all until right + + + align:start position:0% +is hardly changing at all until right +here where it changes very fast and that + + align:start position:0% +here where it changes very fast and that + + + align:start position:0% +here where it changes very fast and that +that leads to gross violations of the + + align:start position:0% +that leads to gross violations of the + + + align:start position:0% +that leads to gross violations of the +Assumption uh that the wave function is + + align:start position:0% +Assumption uh that the wave function is + + + align:start position:0% +Assumption uh that the wave function is +independent or approximately independent + + align:start position:0% +independent or approximately independent + + + align:start position:0% +independent or approximately independent +of internuclear distance and as a result + + align:start position:0% +of internuclear distance and as a result + + + align:start position:0% +of internuclear distance and as a result +there are large coupling + + align:start position:0% +there are large coupling + + + align:start position:0% +there are large coupling +that uh um are outside the zero order + + align:start position:0% +that uh um are outside the zero order + + + align:start position:0% +that uh um are outside the zero order +model and you have to put them in in + + align:start position:0% +model and you have to put them in in + + + align:start position:0% +model and you have to put them in in +order to get the + + align:start position:0% +order to get the + + + align:start position:0% +order to get the +truth and so when you have really really + + align:start position:0% +truth and so when you have really really + + + align:start position:0% +truth and so when you have really really +weak uh configuration interactions + + align:start position:0% +weak uh configuration interactions + + + align:start position:0% +weak uh configuration interactions +really really weak electrostatic + + align:start position:0% +really really weak electrostatic + + + align:start position:0% +really really weak electrostatic +perturbation then you get this cusp if + + align:start position:0% +perturbation then you get this cusp if + + + align:start position:0% +perturbation then you get this cusp if +it's really strong you get a kind of + + align:start position:0% +it's really strong you get a kind of + + + align:start position:0% +it's really strong you get a kind of +behavior sort of like this and uh you + + align:start position:0% +behavior sort of like this and uh you + + + align:start position:0% +behavior sort of like this and uh you +hardly know that there was of an avoided + + align:start position:0% +hardly know that there was of an avoided + + + align:start position:0% +hardly know that there was of an avoided +Crossing because the two halves of the + + align:start position:0% +Crossing because the two halves of the + + + align:start position:0% +Crossing because the two halves of the +avoided Crossing are so far apart and + + align:start position:0% +avoided Crossing are so far apart and + + + align:start position:0% +avoided Crossing are so far apart and +because uh there is so little anomalous + + align:start position:0% +because uh there is so little anomalous + + + align:start position:0% +because uh there is so little anomalous +curvature you don't really know that + + align:start position:0% +curvature you don't really know that + + + align:start position:0% +curvature you don't really know that +that this is different from a simple + + align:start position:0% +that this is different from a simple + + + align:start position:0% +that this is different from a simple +picture of what you expect to go + + align:start position:0% +picture of what you expect to go + + + align:start position:0% +picture of what you expect to go +on okay and so and that also tells you + + align:start position:0% +on okay and so and that also tells you + + + align:start position:0% +on okay and so and that also tells you +that probably the ADBA curves are the + + align:start position:0% +that probably the ADBA curves are the + + + align:start position:0% +that probably the ADBA curves are the +good way to think about the + + align:start position:0% +good way to think about the + + + align:start position:0% +good way to think about the +problem + + align:start position:0% +problem + + + align:start position:0% +problem +and another way of knowing that is if + + align:start position:0% +and another way of knowing that is if + + + align:start position:0% +and another way of knowing that is if +you have something like this half the + + align:start position:0% +you have something like this half the + + + align:start position:0% +you have something like this half the +distance of closest approach is the + + align:start position:0% +distance of closest approach is the + + + align:start position:0% +distance of closest approach is the +electrostatic Matrix element which is + + align:start position:0% +electrostatic Matrix element which is + + + align:start position:0% +electrostatic Matrix element which is +enormous and you don't want to have + + align:start position:0% +enormous and you don't want to have + + + align:start position:0% +enormous and you don't want to have +something enormous off diagonal in your + + align:start position:0% +something enormous off diagonal in your + + + align:start position:0% +something enormous off diagonal in your +model it'll still work but the model + + align:start position:0% +model it'll still work but the model + + + align:start position:0% +model it'll still work but the model +won't look like or what's on the + + align:start position:0% +won't look like or what's on the + + + align:start position:0% +won't look like or what's on the +diagonal of the model won't look like + + align:start position:0% +diagonal of the model won't look like + + + align:start position:0% +diagonal of the model won't look like +what you've + + align:start position:0% + + + + align:start position:0% + +observe so this is I mean it's really + + align:start position:0% +observe so this is I mean it's really + + + align:start position:0% +observe so this is I mean it's really +important to distinguish between the + + align:start position:0% +important to distinguish between the + + + align:start position:0% +important to distinguish between the +model which puts and in fact this is + + align:start position:0% +model which puts and in fact this is + + + align:start position:0% +model which puts and in fact this is +what I left off I didn't uh have a + + align:start position:0% +what I left off I didn't uh have a + + + align:start position:0% +what I left off I didn't uh have a +chance to finish properly at the end of + + align:start position:0% +chance to finish properly at the end of + + + align:start position:0% +chance to finish properly at the end of +last lecture and uh uh so we have a + + align:start position:0% +last lecture and uh uh so we have a + + + align:start position:0% +last lecture and uh uh so we have a +model where the Hiltonia might consist + + align:start position:0% +model where the Hiltonia might consist + + + align:start position:0% +model where the Hiltonia might consist +of three terms we'll call them A and C + + align:start position:0% +of three terms we'll call them A and C + + + align:start position:0% +of three terms we'll call them A and C +but one might be electrostatic one might + + align:start position:0% +but one might be electrostatic one might + + + align:start position:0% +but one might be electrostatic one might +be spin orbit one might be root + + align:start position:0% + + + + align:start position:0% + +and uh you have a choice of what you put + + align:start position:0% +and uh you have a choice of what you put + + + align:start position:0% +and uh you have a choice of what you put +into the zero order picture you could + + align:start position:0% +into the zero order picture you could + + + align:start position:0% +into the zero order picture you could +say for one case you have a + b is a + + align:start position:0% +say for one case you have a + b is a + + + align:start position:0% +say for one case you have a + b is a +zero order picture and in another case + + align:start position:0% +zero order picture and in another case + + + align:start position:0% +zero order picture and in another case +you might have a + + + align:start position:0% +you might have a + + + + align:start position:0% +you might have a + +C it implies that B and + + align:start position:0% +C it implies that B and + + + align:start position:0% +C it implies that B and +C are incompatible + + align:start position:0% +C are incompatible + + + align:start position:0% +C are incompatible +and so in your zero order + + align:start position:0% +and so in your zero order + + + align:start position:0% +and so in your zero order +picture + + align:start position:0% +picture + + + align:start position:0% +picture +um you're out of luck you + + align:start position:0% +um you're out of luck you + + + align:start position:0% +um you're out of luck you +don't + + align:start position:0% + + + + align:start position:0% + +uh okay uh so uh we'll make the copy and + + align:start position:0% + + + + align:start position:0% + +we but what I'm talking about right now + + align:start position:0% +we but what I'm talking about right now + + + align:start position:0% +we but what I'm talking about right now +isn't in anybody's lecture + + align:start position:0% +isn't in anybody's lecture + + + align:start position:0% +isn't in anybody's lecture +Nots + + align:start position:0% +Nots + + + align:start position:0% +Nots +um what why don't I but before we go on + + align:start position:0% +um what why don't I but before we go on + + + align:start position:0% +um what why don't I but before we go on +why don't I circulate this uh list if + + align:start position:0% +why don't I circulate this uh list if + + + align:start position:0% +why don't I circulate this uh list if +you + + align:start position:0% +you + + + align:start position:0% +you +want a PDF copy of the typed lecture + + align:start position:0% +want a PDF copy of the typed lecture + + + align:start position:0% +want a PDF copy of the typed lecture +notes after they're proof read and so on + + align:start position:0% +notes after they're proof read and so on + + + align:start position:0% +notes after they're proof read and so on +put your name and email address here and + + align:start position:0% +put your name and email address here and + + + align:start position:0% +put your name and email address here and +Peter will send them out so the first + + align:start position:0% +Peter will send them out so the first + + + align:start position:0% +Peter will send them out so the first +lecture notes are nearly ready and the + + align:start position:0% +lecture notes are nearly ready and the + + + align:start position:0% +lecture notes are nearly ready and the +SE one second ones will probably be + + align:start position:0% +SE one second ones will probably be + + + align:start position:0% +SE one second ones will probably be +ready + + align:start position:0% + + + + align:start position:0% + +tomorrow okay + + align:start position:0% +tomorrow okay + + + align:start position:0% +tomorrow okay +so + + align:start position:0% +so + + + align:start position:0% +so +B and C are operators which are + + align:start position:0% +B and C are operators which are + + + align:start position:0% +B and C are operators which are +incompatible in other words you can't + + align:start position:0% +incompatible in other words you can't + + + align:start position:0% +incompatible in other words you can't +have states which are I States or of + + align:start position:0% +have states which are I States or of + + + align:start position:0% +have states which are I States or of +both B and C or you can't find a + + align:start position:0% +both B and C or you can't find a + + + align:start position:0% +both B and C or you can't find a +representation in which B and C are both + + align:start position:0% +representation in which B and C are both + + + align:start position:0% +representation in which B and C are both +diagonal you can + + align:start position:0% +diagonal you can + + + align:start position:0% +diagonal you can +diagonalize a and b simultaneously and A + + align:start position:0% +diagonalize a and b simultaneously and A + + + align:start position:0% +diagonalize a and b simultaneously and A +and C + + align:start position:0% +and C + + + align:start position:0% +and C +simultaneously but not B and C these are + + align:start position:0% +simultaneously but not B and C these are + + + align:start position:0% +simultaneously but not B and C these are +two mutually incompatible terms in your + + align:start position:0% +two mutually incompatible terms in your + + + align:start position:0% +two mutually incompatible terms in your +picture and you always make a choice + + align:start position:0% +picture and you always make a choice + + + align:start position:0% +picture and you always make a choice +there are always going to be mutually + + align:start position:0% +there are always going to be mutually + + + align:start position:0% +there are always going to be mutually +incompatible terms in your model for + + align:start position:0% +incompatible terms in your model for + + + align:start position:0% +incompatible terms in your model for +what's going on and you have to choose + + align:start position:0% +what's going on and you have to choose + + + align:start position:0% +what's going on and you have to choose +which one is the one that is better to + + align:start position:0% +which one is the one that is better to + + + align:start position:0% +which one is the one that is better to +put into the zero order picture so + + align:start position:0% +put into the zero order picture so + + + align:start position:0% +put into the zero order picture so +you'll capture most of the important + + align:start position:0% +you'll capture most of the important + + + align:start position:0% +you'll capture most of the important +structure that you're going to see in + + align:start position:0% +structure that you're going to see in + + + align:start position:0% +structure that you're going to see in +the + + align:start position:0% +the + + + align:start position:0% +the +experiment and then you put the other + + align:start position:0% +experiment and then you put the other + + + align:start position:0% +experiment and then you put the other +one in as a + + align:start position:0% +one in as a + + + align:start position:0% +one in as a +perturbation + + align:start position:0% +perturbation + + + align:start position:0% +perturbation +and you then uh use the I states of the + + align:start position:0% +and you then uh use the I states of the + + + align:start position:0% +and you then uh use the I states of the +part of the problem you've chosen to + + align:start position:0% +part of the problem you've chosen to + + + align:start position:0% +part of the problem you've chosen to +make H + + align:start position:0% +make H + + + align:start position:0% +make H +zero to evaluate the effects of the + + align:start position:0% +zero to evaluate the effects of the + + + align:start position:0% +zero to evaluate the effects of the +missing + + align:start position:0% +missing + + + align:start position:0% +missing +part and this + + align:start position:0% +part and this + + + align:start position:0% +part and this +is basically that's all spectroscopy is + + align:start position:0% +is basically that's all spectroscopy is + + + align:start position:0% +is basically that's all spectroscopy is +in fact I would imagine that's pretty + + align:start position:0% +in fact I would imagine that's pretty + + + align:start position:0% +in fact I would imagine that's pretty +much all uh any representation of a + + align:start position:0% +much all uh any representation of a + + + align:start position:0% +much all uh any representation of a +complex situation is that you you say + + align:start position:0% +complex situation is that you you say + + + align:start position:0% +complex situation is that you you say +this is the part that that is uh that + + align:start position:0% +this is the part that that is uh that + + + align:start position:0% +this is the part that that is uh that +captures most of the problem and that I + + align:start position:0% +captures most of the problem and that I + + + align:start position:0% +captures most of the problem and that I +can describe + + align:start position:0% +can describe + + + align:start position:0% +can describe +it in a + + align:start position:0% +it in a + + + align:start position:0% +it in a +convenient way and then I put in the + + align:start position:0% +convenient way and then I put in the + + + align:start position:0% +convenient way and then I put in the +other part as uh some kind of a + + align:start position:0% +other part as uh some kind of a + + + align:start position:0% +other part as uh some kind of a +perturbation term which I also treat + + align:start position:0% +perturbation term which I also treat + + + align:start position:0% +perturbation term which I also treat +accurately and honestly and completely + + align:start position:0% +accurately and honestly and completely + + + align:start position:0% +accurately and honestly and completely +but only as a modification of what is + + align:start position:0% +but only as a modification of what is + + + align:start position:0% +but only as a modification of what is +the fundamental Simplicity of this + + align:start position:0% +the fundamental Simplicity of this + + + align:start position:0% +the fundamental Simplicity of this +particular particular situation and let + + align:start position:0% +particular particular situation and let + + + align:start position:0% +particular particular situation and let +me uh uh be a little more + + align:start position:0% +me uh uh be a little more + + + align:start position:0% +me uh uh be a little more +specific in the hamiltonian for a + + align:start position:0% +specific in the hamiltonian for a + + + align:start position:0% +specific in the hamiltonian for a +diatomic molecule we have a contribution + + align:start position:0% +diatomic molecule we have a contribution + + + align:start position:0% +diatomic molecule we have a contribution +from the spin orbit + + align:start position:0% +from the spin orbit + + + align:start position:0% +from the spin orbit +operator the spin orbit constant times + + align:start position:0% +operator the spin orbit constant times + + + align:start position:0% +operator the spin orbit constant times +lzs this gives rise to the spin orbit + + align:start position:0% +lzs this gives rise to the spin orbit + + + align:start position:0% +lzs this gives rise to the spin orbit +splitting of a multipet + + align:start position:0% + + + + align:start position:0% + +state and we also have a term from the + + align:start position:0% +state and we also have a term from the + + + align:start position:0% +state and we also have a term from the +rotational hamiltonian the rotational + + align:start position:0% +rotational hamiltonian the rotational + + + align:start position:0% +rotational hamiltonian the rotational +constant + + align:start position:0% +constant + + + align:start position:0% +constant +times uh J + + + align:start position:0% +times uh J + + + + align:start position:0% +times uh J + +s- say minus + + align:start position:0% +s- say minus + + + align:start position:0% +s- say minus +s+ where this is called the spin + + align:start position:0% +s+ where this is called the spin + + + align:start position:0% +s+ where this is called the spin +uncoupling + + align:start position:0% +uncoupling + + + align:start position:0% +uncoupling +term this is off diagonal between states + + align:start position:0% +term this is off diagonal between states + + + align:start position:0% +term this is off diagonal between states +of different values of the projection + + align:start position:0% +of different values of the projection + + + align:start position:0% +of different values of the projection +quantum number + + align:start position:0% +quantum number + + + align:start position:0% +quantum number +JZ and the projection quantum number for + + align:start position:0% +JZ and the projection quantum number for + + + align:start position:0% +JZ and the projection quantum number for +SZ this is called Omega and this is + + align:start position:0% +SZ this is called Omega and this is + + + align:start position:0% +SZ this is called Omega and this is +called Sigma so we could choose a basis + + align:start position:0% +called Sigma so we could choose a basis + + + align:start position:0% +called Sigma so we could choose a basis +set where this is + + align:start position:0% + + + + align:start position:0% + +diagonal and as a result this goes into + + align:start position:0% +diagonal and as a result this goes into + + + align:start position:0% +diagonal and as a result this goes into +h0 and this is not diagonal and this + + align:start position:0% +h0 and this is not diagonal and this + + + align:start position:0% +h0 and this is not diagonal and this +term we we call the perturbation term + + align:start position:0% +term we we call the perturbation term + + + align:start position:0% +term we we call the perturbation term +and it leads to + + align:start position:0% +and it leads to + + + align:start position:0% +and it leads to +small modifications of a characteristic + + align:start position:0% +small modifications of a characteristic + + + align:start position:0% +small modifications of a characteristic +pattern which is easy to + + align:start position:0% +pattern which is easy to + + + align:start position:0% +pattern which is easy to +recognize and that called hun case + + align:start position:0% +recognize and that called hun case + + + align:start position:0% +recognize and that called hun case +a or we can put this + + align:start position:0% +a or we can put this + + + align:start position:0% +a or we can put this +in and this forces us to a situation + + align:start position:0% +in and this forces us to a situation + + + align:start position:0% +in and this forces us to a situation +where the good quantum number is n which + + align:start position:0% +where the good quantum number is n which + + + align:start position:0% +where the good quantum number is n which +is J - + + align:start position:0% +is J - + + + align:start position:0% +is J - +s and then the rotational levels go as B + + align:start position:0% +s and then the rotational levels go as B + + + align:start position:0% +s and then the rotational levels go as B +* NN + 1 and there's nothing from the + + align:start position:0% +* NN + 1 and there's nothing from the + + + align:start position:0% +* NN + 1 and there's nothing from the +rotational hamiltonian that's off + + align:start position:0% +rotational hamiltonian that's off + + + align:start position:0% +rotational hamiltonian that's off +diagonal but this is off + + align:start position:0% + + + + align:start position:0% + +diag and that's called H's case b now + + align:start position:0% +diag and that's called H's case b now + + + align:start position:0% +diag and that's called H's case b now +let me + + align:start position:0% +let me + + + align:start position:0% +let me +also take something from the last page + + align:start position:0% +also take something from the last page + + + align:start position:0% +also take something from the last page +of the notes from last time that we + + align:start position:0% +of the notes from last time that we + + + align:start position:0% +of the notes from last time that we +didn't get to so let's say we have two + + align:start position:0% +didn't get to so let's say we have two + + + align:start position:0% +didn't get to so let's say we have two +hamiltonians hamiltonian number + + align:start position:0% +hamiltonians hamiltonian number + + + align:start position:0% +hamiltonians hamiltonian number +one which has the form Delta 2 0 0us + + align:start position:0% +one which has the form Delta 2 0 0us + + + align:start position:0% +one which has the form Delta 2 0 0us +Delta 2 in other words splitting of the + + align:start position:0% +Delta 2 in other words splitting of the + + + align:start position:0% +Delta 2 in other words splitting of the +states on the diagonal of + + align:start position:0% + + + + align:start position:0% + +Delta so there's some term in the + + align:start position:0% +Delta so there's some term in the + + + align:start position:0% +Delta so there's some term in the +hamiltonian that lifts a + + align:start position:0% +hamiltonian that lifts a + + + align:start position:0% +hamiltonian that lifts a +degeneracy that creates a + + align:start position:0% +degeneracy that creates a + + + align:start position:0% +degeneracy that creates a +pattern and there's going to be another + + align:start position:0% +pattern and there's going to be another + + + align:start position:0% +pattern and there's going to be another +term in the hamiltonian that tries to + + align:start position:0% +term in the hamiltonian that tries to + + + align:start position:0% +term in the hamiltonian that tries to +destroy that pattern now for a 2X two + + align:start position:0% +destroy that pattern now for a 2X two + + + align:start position:0% +destroy that pattern now for a 2X two +it's easy to do all the algebra but + + align:start position:0% +it's easy to do all the algebra but + + + align:start position:0% +it's easy to do all the algebra but +generally the the problems we deal with + + align:start position:0% +generally the the problems we deal with + + + align:start position:0% +generally the the problems we deal with +are a little bit bigger than 2x two but + + align:start position:0% +are a little bit bigger than 2x two but + + + align:start position:0% +are a little bit bigger than 2x two but +not much bigger but the pattern is much + + align:start position:0% +not much bigger but the pattern is much + + + align:start position:0% +not much bigger but the pattern is much +harder to see and the amount of crank + + align:start position:0% +harder to see and the amount of crank + + + align:start position:0% +harder to see and the amount of crank +turning to to do the algebra is much + + align:start position:0% +turning to to do the algebra is much + + + align:start position:0% +turning to to do the algebra is much +more severe so this the other + + align:start position:0% +more severe so this the other + + + align:start position:0% +more severe so this the other +hilon uh is 0 0 + + align:start position:0% +hilon uh is 0 0 + + + align:start position:0% +hilon uh is 0 0 +BB this is an off diagonal hamiltonian + + align:start position:0% +BB this is an off diagonal hamiltonian + + + align:start position:0% +BB this is an off diagonal hamiltonian +with no difference in energy on the + + align:start position:0% +with no difference in energy on the + + + align:start position:0% +with no difference in energy on the +diagonal so our full hamiltonian is the + + align:start position:0% +diagonal so our full hamiltonian is the + + + align:start position:0% +diagonal so our full hamiltonian is the +sum of these + + align:start position:0% + + + + align:start position:0% + +two + + align:start position:0% +two + + + align:start position:0% +two +now we can use a basis set where this + + align:start position:0% +now we can use a basis set where this + + + align:start position:0% +now we can use a basis set where this +hamiltonian stays + + align:start position:0% + + + + align:start position:0% + +diagonal but then there's going to be + + align:start position:0% +diagonal but then there's going to be + + + align:start position:0% +diagonal but then there's going to be +this thing here and we either do + + align:start position:0% +this thing here and we either do + + + align:start position:0% +this thing here and we either do +corrections by second order perturbation + + align:start position:0% +corrections by second order perturbation + + + align:start position:0% +corrections by second order perturbation +Theory which would be correct the + + align:start position:0% +Theory which would be correct the + + + align:start position:0% +Theory which would be correct the +energies by v^2 over Delta provided V + + align:start position:0% +energies by v^2 over Delta provided V + + + align:start position:0% +energies by v^2 over Delta provided V +over Delta absolute value is less than + + align:start position:0% +over Delta absolute value is less than + + + align:start position:0% +over Delta absolute value is less than +one that's the the uh convergence + + align:start position:0% +one that's the the uh convergence + + + align:start position:0% +one that's the the uh convergence +Criterion for ation + + align:start position:0% +Criterion for ation + + + align:start position:0% +Criterion for ation +Theory when V over Delta is not less + + align:start position:0% +Theory when V over Delta is not less + + + align:start position:0% +Theory when V over Delta is not less +than one then we actually have to + + align:start position:0% +than one then we actually have to + + + align:start position:0% +than one then we actually have to +diagonalize this + + align:start position:0% +diagonalize this + + + align:start position:0% +diagonalize this +Matrix now this is an easy Matrix to + + align:start position:0% +Matrix now this is an easy Matrix to + + + align:start position:0% +Matrix now this is an easy Matrix to +diagonalize because the off diagonal the + + align:start position:0% +diagonalize because the off diagonal the + + + align:start position:0% +diagonalize because the off diagonal the +diagonal elements have the same energy I + + align:start position:0% +diagonal elements have the same energy I + + + align:start position:0% +diagonal elements have the same energy I +can write down the transformation to + + align:start position:0% +can write down the transformation to + + + align:start position:0% +can write down the transformation to +diagonalize that without + + align:start position:0% +diagonalize that without + + + align:start position:0% +diagonalize that without +thinking so what I'm going to do is go + + align:start position:0% +thinking so what I'm going to do is go + + + align:start position:0% +thinking so what I'm going to do is go +to the basis + + align:start position:0% +to the basis + + + align:start position:0% +to the basis +set or go to the igen vectors of + + align:start position:0% +set or go to the igen vectors of + + + align:start position:0% +set or go to the igen vectors of +this okay and those are 1 > 2 * 1 + or - + + align:start position:0% +this okay and those are 1 > 2 * 1 + or - + + + align:start position:0% +this okay and those are 1 > 2 * 1 + or - +2 where these are the I vectors of + + align:start position:0% + + + + align:start position:0% + +this okay is for the people who only had + + align:start position:0% +this okay is for the people who only had + + + align:start position:0% +this okay is for the people who only had + + align:start position:0% + + + align:start position:0% +or who haven't had 561 this is a reach + + align:start position:0% +or who haven't had 561 this is a reach + + + align:start position:0% +or who haven't had 561 this is a reach +but I want you to get this for my + + align:start position:0% +but I want you to get this for my + + + align:start position:0% +but I want you to get this for my +students this is not a reach but this is + + align:start position:0% +students this is not a reach but this is + + + align:start position:0% +students this is not a reach but this is +really a crucial + + align:start position:0% +really a crucial + + + align:start position:0% +really a crucial +Point okay + + align:start position:0% +Point okay + + + align:start position:0% +Point okay +so this will diagonalize this + + align:start position:0% +so this will diagonalize this + + + align:start position:0% +so this will diagonalize this +honia and how do we know that well let's + + align:start position:0% +honia and how do we know that well let's + + + align:start position:0% +honia and how do we know that well let's +calculate the Matrix elements + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% + + + + align:start position:0% + +okay so this is the symbol let's take + + align:start position:0% +okay so this is the symbol let's take + + + align:start position:0% +okay so this is the symbol let's take +the Diagon the the plus with the Plus or + + align:start position:0% +the Diagon the the plus with the Plus or + + + align:start position:0% +the Diagon the the plus with the Plus or +the minus with the minus so these are + + align:start position:0% +the minus with the minus so these are + + + align:start position:0% +the minus with the minus so these are +actually two elements at once and this + + align:start position:0% +actually two elements at once and this + + + align:start position:0% +actually two elements at once and this +is plus with the minus or minus with the + + align:start position:0% +is plus with the minus or minus with the + + + align:start position:0% +is plus with the minus or minus with the +plus and uh so we're going to have to + + align:start position:0% +plus and uh so we're going to have to + + + align:start position:0% +plus and uh so we're going to have to +wave function twice so we'll get 1 2 SAR + + align:start position:0% +wave function twice so we'll get 1 2 SAR + + + align:start position:0% +wave function twice so we'll get 1 2 SAR +so we'll get a half + + align:start position:0% +so we'll get a half + + + align:start position:0% +so we'll get a half +and then uh we'll have + + align:start position:0% +and then uh we'll have + + + align:start position:0% +and then uh we'll have +h211 plus H2 + + align:start position:0% + + + + align:start position:0% + +22 plus or minus + + align:start position:0% +22 plus or minus + + + align:start position:0% +22 plus or minus +h212 plus orus H2 + + align:start position:0% + + + + align:start position:0% + +21 okay so in H2 these two things are + + align:start position:0% +21 okay so in H2 these two things are + + + align:start position:0% +21 okay so in H2 these two things are +zero + + align:start position:0% +zero + + + align:start position:0% +zero +and these two things are both V and so + + align:start position:0% +and these two things are both V and so + + + align:start position:0% +and these two things are both V and so +we get plus or minus + + align:start position:0% + + + + align:start position:0% + +V and when we go through so we're just + + align:start position:0% +V and when we go through so we're just + + + align:start position:0% +V and when we go through so we're just +putting this in and calculating the + + align:start position:0% +putting this in and calculating the + + + align:start position:0% +putting this in and calculating the +Matrix elements of these things now I + + align:start position:0% +Matrix elements of these things now I + + + align:start position:0% +Matrix elements of these things now I +can do this sort of almost in my head + + align:start position:0% +can do this sort of almost in my head + + + align:start position:0% +can do this sort of almost in my head +but this is going to require a little + + align:start position:0% +but this is going to require a little + + + align:start position:0% +but this is going to require a little +bit of study from people who haven't + + align:start position:0% +bit of study from people who haven't + + + align:start position:0% +bit of study from people who haven't +done it before okay but I want to write + + align:start position:0% +done it before okay but I want to write + + + align:start position:0% +done it before okay but I want to write +it out so that you can convince yourself + + align:start position:0% +it out so that you can convince yourself + + + align:start position:0% +it out so that you can convince yourself +that you can derive + + align:start position:0% +that you can derive + + + align:start position:0% +that you can derive +that it would have been easier if I just + + align:start position:0% +that it would have been easier if I just + + + align:start position:0% +that it would have been easier if I just +wrote an extra + + align:start position:0% +wrote an extra + + + align:start position:0% +wrote an extra +line on the black + + align:start position:0% +line on the black + + + align:start position:0% +line on the black +board okay uh for the second one we have + + align:start position:0% +board okay uh for the second one we have + + + align:start position:0% +board okay uh for the second one we have +a half time + + align:start position:0% +a half time + + + align:start position:0% +a half time +h11 uh for Hamilton number two- H2 + + align:start position:0% +h11 uh for Hamilton number two- H2 + + + align:start position:0% +h11 uh for Hamilton number two- H2 +2 2 minus or plus + + align:start position:0% +2 2 minus or plus + + + align:start position:0% +2 2 minus or plus +H1 2 plus or + + align:start position:0% +H1 2 plus or + + + align:start position:0% +H1 2 plus or +minus 2 + + align:start position:0% +minus 2 + + + align:start position:0% +minus 2 +one and these These are zero but this is + + align:start position:0% +one and these These are zero but this is + + + align:start position:0% +one and these These are zero but this is +V and this is V and so whichever choice + + align:start position:0% +V and this is V and so whichever choice + + + align:start position:0% +V and this is V and so whichever choice +of sign we choose we get zero and so H2 + + align:start position:0% +of sign we choose we get zero and so H2 + + + align:start position:0% +of sign we choose we get zero and so H2 +transform give it that little symbol + + align:start position:0% +transform give it that little symbol + + + align:start position:0% +transform give it that little symbol +looks like this V 0 0 - + + align:start position:0% + + + + align:start position:0% + +V we go through the same thing for + + align:start position:0% + + + + align:start position:0% + +H1 and I'm just going to write that + + align:start position:0% +H1 and I'm just going to write that + + + align:start position:0% +H1 and I'm just going to write that +down uh for H1 when we transform + + align:start position:0% +down uh for H1 when we transform + + + align:start position:0% +down uh for H1 when we transform +H1 we + + align:start position:0% +H1 we + + + align:start position:0% +H1 we +get 0 Delta 2 Delta + + align:start position:0% +get 0 Delta 2 Delta + + + align:start position:0% +get 0 Delta 2 Delta +zero doesn't it look interesting this + + align:start position:0% +zero doesn't it look interesting this + + + align:start position:0% +zero doesn't it look interesting this +looks + + align:start position:0% +looks + + + align:start position:0% +looks +almost like the + + align:start position:0% +almost like the + + + align:start position:0% +almost like the +old + + align:start position:0% +old + + + align:start position:0% +old +H2 we have the same number off diagonal + + align:start position:0% +H2 we have the same number off diagonal + + + align:start position:0% +H2 we have the same number off diagonal +nothing on + + align:start position:0% +nothing on + + + align:start position:0% +nothing on +diagonal and this looks like the old + + align:start position:0% +diagonal and this looks like the old + + + align:start position:0% +diagonal and this looks like the old +H1 we have the same number but with + + align:start position:0% +H1 we have the same number but with + + + align:start position:0% +H1 we have the same number but with +opposite sign of the + + align:start position:0% +opposite sign of the + + + align:start position:0% +opposite sign of the +diagonal so if we choose to choose one + + align:start position:0% +diagonal so if we choose to choose one + + + align:start position:0% +diagonal so if we choose to choose one +basis set we have one term on the + + align:start position:0% +basis set we have one term on the + + + align:start position:0% +basis set we have one term on the +diagonal creating a difference in energy + + align:start position:0% +diagonal creating a difference in energy + + + align:start position:0% +diagonal creating a difference in energy +between the + + align:start position:0% +between the + + + align:start position:0% +between the +states and the other term off the + + align:start position:0% +states and the other term off the + + + align:start position:0% +states and the other term off the +ago trying to spoil that + + align:start position:0% + + + + align:start position:0% + +picture if we choose the opposite + + align:start position:0% +picture if we choose the opposite + + + align:start position:0% +picture if we choose the opposite +basis the roles of the two terms the + + align:start position:0% +basis the roles of the two terms the + + + align:start position:0% +basis the roles of the two terms the +good term and the bad term switch and + + align:start position:0% +good term and the bad term switch and + + + align:start position:0% +good term and the bad term switch and +good becomes bad and bad becomes + + align:start position:0% + + + + align:start position:0% + +good and this is everywhere what is + + align:start position:0% +good and this is everywhere what is + + + align:start position:0% +good and this is everywhere what is +happening and + + align:start position:0% +happening and + + + align:start position:0% +happening and +sometimes uh in order to understand the + + align:start position:0% +sometimes uh in order to understand the + + + align:start position:0% +sometimes uh in order to understand the +mechanism of what's going on it's + + align:start position:0% +mechanism of what's going on it's + + + align:start position:0% +mechanism of what's going on it's +necessary to make one of these + + align:start position:0% +necessary to make one of these + + + align:start position:0% +necessary to make one of these +Transformations and the reason for some + + align:start position:0% +Transformations and the reason for some + + + align:start position:0% +Transformations and the reason for some +off diagonal interaction between states + + align:start position:0% +off diagonal interaction between states + + + align:start position:0% +off diagonal interaction between states +that leads to some Dynamics or some + + align:start position:0% +that leads to some Dynamics or some + + + align:start position:0% +that leads to some Dynamics or some +complexity in the Spectrum is much + + align:start position:0% +complexity in the Spectrum is much + + + align:start position:0% +complexity in the Spectrum is much +clearer in one representation as opposed + + align:start position:0% +clearer in one representation as opposed + + + align:start position:0% +clearer in one representation as opposed +to the + + align:start position:0% + + + + align:start position:0% + +other and + + align:start position:0% +other and + + + align:start position:0% +other and +uh one example of that which we might + + align:start position:0% +uh one example of that which we might + + + align:start position:0% +uh one example of that which we might +get to today and might not get to it all + + align:start position:0% +get to today and might not get to it all + + + align:start position:0% +get to today and might not get to it all +is rotational Auto + + align:start position:0% +is rotational Auto + + + align:start position:0% +is rotational Auto +ionization I'll get to that I'll talk + + align:start position:0% +ionization I'll get to that I'll talk + + + align:start position:0% +ionization I'll get to that I'll talk +about + + align:start position:0% +about + + + align:start position:0% +about +perturbations now okay + + align:start position:0% +perturbations now okay + + + align:start position:0% +perturbations now okay +so this is what was left from the last + + align:start position:0% +so this is what was left from the last + + + align:start position:0% +so this is what was left from the last +lecture + + align:start position:0% +lecture + + + align:start position:0% +lecture +and it's probably the most important + + align:start position:0% +and it's probably the most important + + + align:start position:0% +and it's probably the most important +point from the last lecture we have + + align:start position:0% +point from the last lecture we have + + + align:start position:0% +point from the last lecture we have +always mutually incompatible terms in + + align:start position:0% +always mutually incompatible terms in + + + align:start position:0% +always mutually incompatible terms in +the hamiltonian and we choose one to go + + align:start position:0% +the hamiltonian and we choose one to go + + + align:start position:0% +the hamiltonian and we choose one to go +into h0 and the rest to put uh off + + align:start position:0% +into h0 and the rest to put uh off + + + align:start position:0% +into h0 and the rest to put uh off +diagonal and treat as + + align:start position:0% + + + + align:start position:0% + +perturbations every choice when you do + + align:start position:0% +perturbations every choice when you do + + + align:start position:0% +perturbations every choice when you do +the problem completely including all the + + align:start position:0% +the problem completely including all the + + + align:start position:0% +the problem completely including all the +off elements gives an equally good + + align:start position:0% +off elements gives an equally good + + + align:start position:0% +off elements gives an equally good +representation of reality + + align:start position:0% + + + + align:start position:0% + +but the different approaches when you + + align:start position:0% +but the different approaches when you + + + align:start position:0% +but the different approaches when you +ignore the + + align:start position:0% +ignore the + + + align:start position:0% +ignore the +alagon give very different + + align:start position:0% +alagon give very different + + + align:start position:0% +alagon give very different +correspondence to + + align:start position:0% +correspondence to + + + align:start position:0% +correspondence to +reality an appropriate representation + + align:start position:0% +reality an appropriate representation + + + align:start position:0% +reality an appropriate representation +gives a + + align:start position:0% +gives a + + + align:start position:0% +gives a +recognizable uh description of reality + + align:start position:0% +recognizable uh description of reality + + + align:start position:0% +recognizable uh description of reality +where there are small + + align:start position:0% + + + + align:start position:0% + +deviations + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +The crucial actor in our treatment of + + align:start position:0% +The crucial actor in our treatment of + + + align:start position:0% +The crucial actor in our treatment of +molecules was the Bor Oppenheimer + + align:start position:0% + + + + align:start position:0% + +approximation so I keep dividing up the + + align:start position:0% +approximation so I keep dividing up the + + + align:start position:0% +approximation so I keep dividing up the +Hamilton slightly different we have the + + align:start position:0% +Hamilton slightly different we have the + + + align:start position:0% +Hamilton slightly different we have the +electronic plus + + align:start position:0% + + + + align:start position:0% + +vibrational we have spin + + align:start position:0% +vibrational we have spin + + + align:start position:0% +vibrational we have spin +orb and + + align:start position:0% +orb and + + + align:start position:0% +orb and +rotation the reason I put these together + + align:start position:0% +rotation the reason I put these together + + + align:start position:0% +rotation the reason I put these together +is that when we do the born Oppenheimer + + align:start position:0% +is that when we do the born Oppenheimer + + + align:start position:0% +is that when we do the born Oppenheimer +approximation we generate the potential + + align:start position:0% +approximation we generate the potential + + + align:start position:0% +approximation we generate the potential +curves and once we have the potential + + align:start position:0% +curves and once we have the potential + + + align:start position:0% +curves and once we have the potential +curves we solve the vibrational + + align:start position:0% +curves we solve the vibrational + + + align:start position:0% +curves we solve the vibrational +problem and uh whether we make a + + align:start position:0% +problem and uh whether we make a + + + align:start position:0% +problem and uh whether we make a +diabetic or adiabetic choice we get + + align:start position:0% +diabetic or adiabetic choice we get + + + align:start position:0% +diabetic or adiabetic choice we get +different potential curves so the + + align:start position:0% +different potential curves so the + + + align:start position:0% +different potential curves so the +vibrational problem is different but + + align:start position:0% +vibrational problem is different but + + + align:start position:0% +vibrational problem is different but +it's the same crank you turn you have a + + align:start position:0% +it's the same crank you turn you have a + + + align:start position:0% +it's the same crank you turn you have a +potential energy curve + + align:start position:0% +potential energy curve + + + align:start position:0% +potential energy curve +and you have the nuclear kinetic energy + + align:start position:0% +and you have the nuclear kinetic energy + + + align:start position:0% +and you have the nuclear kinetic energy +you solve the nuclear shorting equation + + align:start position:0% +you solve the nuclear shorting equation + + + align:start position:0% +you solve the nuclear shorting equation +you get IG functions and I + + align:start position:0% + + + + align:start position:0% + +Val + + align:start position:0% +Val + + + align:start position:0% +Val +okay the most for diatomic molecules the + + align:start position:0% +okay the most for diatomic molecules the + + + align:start position:0% +okay the most for diatomic molecules the +most convenient from the point of view + + align:start position:0% +most convenient from the point of view + + + align:start position:0% +most convenient from the point of view +of writing down Matrix elements and + + align:start position:0% +of writing down Matrix elements and + + + align:start position:0% +of writing down Matrix elements and +representing the problem the most + + align:start position:0% +representing the problem the most + + + align:start position:0% +representing the problem the most +convenient basis set is generally the + + align:start position:0% +convenient basis set is generally the + + + align:start position:0% +convenient basis set is generally the +Huns case a basis set and so case + + align:start position:0% +Huns case a basis set and so case + + + align:start position:0% +Huns case a basis set and so case +a basis functions look like this we have + + align:start position:0% +a basis functions look like this we have + + + align:start position:0% +a basis functions look like this we have +the + + align:start position:0% +the + + + align:start position:0% +the +electronic uh a symbol that says which + + align:start position:0% +electronic uh a symbol that says which + + + align:start position:0% +electronic uh a symbol that says which +electronic statement come with an i and + + align:start position:0% +electronic statement come with an i and + + + align:start position:0% +electronic statement come with an i and +then we have L which is never really + + align:start position:0% +then we have L which is never really + + + align:start position:0% +then we have L which is never really +good but we often include it as a uh + + align:start position:0% +good but we often include it as a uh + + + align:start position:0% +good but we often include it as a uh +label Lambda s + + align:start position:0% +label Lambda s + + + align:start position:0% +label Lambda s +Sigma and then Omega k m + + align:start position:0% +Sigma and then Omega k m + + + align:start position:0% +Sigma and then Omega k m +so these are the quantum numbers and + + align:start position:0% +so these are the quantum numbers and + + + align:start position:0% +so these are the quantum numbers and +these are our basis + + align:start position:0% +these are our basis + + + align:start position:0% +these are our basis +functions and in order to make any + + align:start position:0% +functions and in order to make any + + + align:start position:0% +functions and in order to make any +progress with diatomic molecules we need + + align:start position:0% +progress with diatomic molecules we need + + + align:start position:0% +progress with diatomic molecules we need +to know how to evaluate Matrix elements + + align:start position:0% +to know how to evaluate Matrix elements + + + align:start position:0% +to know how to evaluate Matrix elements +of all operators in the hamiltonian in + + align:start position:0% +of all operators in the hamiltonian in + + + align:start position:0% +of all operators in the hamiltonian in +this + + align:start position:0% + + + + align:start position:0% + +basis + + align:start position:0% +basis + + + align:start position:0% +basis +so for + + align:start position:0% +so for + + + align:start position:0% +so for +angular + + align:start position:0% +angular + + + align:start position:0% +angular +momentum + + align:start position:0% + + + + align:start position:0% + +Matrix + + align:start position:0% + + + + align:start position:0% + +elements you want to look at + + align:start position:0% +elements you want to look at + + + align:start position:0% +elements you want to look at +Pages 72 to 81 for my book which I + + align:start position:0% +Pages 72 to 81 for my book which I + + + align:start position:0% +Pages 72 to 81 for my book which I +handed out until I ran out of + + align:start position:0% +handed out until I ran out of + + + align:start position:0% +handed out until I ran out of +copies uh some of you haven't it's it's + + align:start position:0% +copies uh some of you haven't it's it's + + + align:start position:0% +copies uh some of you haven't it's it's +in that + + align:start position:0% +in that + + + align:start position:0% +in that +handout + + align:start position:0% +handout + + + align:start position:0% +handout +uh there's three pages that are with + + align:start position:0% +uh there's three pages that are with + + + align:start position:0% +uh there's three pages that are with +nice pictures which I'll get to and then + + align:start position:0% +nice pictures which I'll get to and then + + + align:start position:0% +nice pictures which I'll get to and then +there is the Machinery okay so let us + + align:start position:0% +there is the Machinery okay so let us + + + align:start position:0% +there is the Machinery okay so let us +say that a is an angular momentum and + + align:start position:0% +say that a is an angular momentum and + + + align:start position:0% +say that a is an angular momentum and +some operator some angular momentum and + + align:start position:0% +some operator some angular momentum and + + + align:start position:0% +some operator some angular momentum and +the nice thing about angular momenta is + + align:start position:0% +the nice thing about angular momenta is + + + align:start position:0% +the nice thing about angular momenta is +that once you know what the Matrix + + align:start position:0% +that once you know what the Matrix + + + align:start position:0% +that once you know what the Matrix +elements for one angular momentum are + + align:start position:0% +elements for one angular momentum are + + + align:start position:0% +elements for one angular momentum are +you know them all and + + align:start position:0% +you know them all and + + + align:start position:0% +you know them all and +so we have the angular momentum Square + + align:start position:0% +so we have the angular momentum Square + + + align:start position:0% +so we have the angular momentum Square +operating on + + align:start position:0% +operating on + + + align:start position:0% +operating on +a basis function which is expressed with + + align:start position:0% +a basis function which is expressed with + + + align:start position:0% +a basis function which is expressed with +two quantum numbers the quantum number + + align:start position:0% +two quantum numbers the quantum number + + + align:start position:0% +two quantum numbers the quantum number +associated with the total angular + + align:start position:0% +associated with the total angular + + + align:start position:0% +associated with the total angular +momentum and with a projection of that + + align:start position:0% +momentum and with a projection of that + + + align:start position:0% +momentum and with a projection of that +angular + + align:start position:0% +angular + + + align:start position:0% +angular +momentum projection on what we call the + + align:start position:0% +momentum projection on what we call the + + + align:start position:0% +momentum projection on what we call the +the Symmetry Axis or the + + align:start position:0% +the Symmetry Axis or the + + + align:start position:0% +the Symmetry Axis or the +z-axis okay we're two free to choose but + + align:start position:0% +z-axis okay we're two free to choose but + + + align:start position:0% +z-axis okay we're two free to choose but +in diatomic molecules you would be kind + + align:start position:0% +in diatomic molecules you would be kind + + + align:start position:0% +in diatomic molecules you would be kind +of stupid to choose anything but the + + align:start position:0% +of stupid to choose anything but the + + + align:start position:0% +of stupid to choose anything but the +internuclear axis of Z because that's an + + align:start position:0% +internuclear axis of Z because that's an + + + align:start position:0% +internuclear axis of Z because that's an +axis of cylindri iCal symmetry but it + + align:start position:0% +axis of cylindri iCal symmetry but it + + + align:start position:0% +axis of cylindri iCal symmetry but it +turns out that for ridberg States + + align:start position:0% +turns out that for ridberg States + + + align:start position:0% +turns out that for ridberg States +sometimes the quantization axis is not + + align:start position:0% +sometimes the quantization axis is not + + + align:start position:0% +sometimes the quantization axis is not +the internuclear axis but it's the axis + + align:start position:0% +the internuclear axis but it's the axis + + + align:start position:0% +the internuclear axis but it's the axis +about which the molecule + + align:start position:0% +about which the molecule + + + align:start position:0% +about which the molecule +rotates and that leads to some + + align:start position:0% +rotates and that leads to some + + + align:start position:0% +rotates and that leads to some +Strang but so you have a magnitude and a + + align:start position:0% +Strang but so you have a magnitude and a + + + align:start position:0% +Strang but so you have a magnitude and a +projection and so you get a a + + align:start position:0% +projection and so you get a a + + + align:start position:0% +projection and so you get a a ++1 a + + align:start position:0% ++1 a + + + align:start position:0% ++1 a +Al + + align:start position:0% +Al + + + align:start position:0% +Al +we have the space fixed the the + + align:start position:0% +we have the space fixed the the + + + align:start position:0% +we have the space fixed the the +laborator sorry the body fixed + + align:start position:0% +laborator sorry the body fixed + + + align:start position:0% +laborator sorry the body fixed +zis + + align:start position:0% + + + + align:start position:0% + +projection and that's Alpha a + + align:start position:0% + + + + align:start position:0% + +Al then we have the raising and lowering + + align:start position:0% +Al then we have the raising and lowering + + + align:start position:0% +Al then we have the raising and lowering +operators which are a X plus orus I a y + + align:start position:0% +operators which are a X plus orus I a y + + + align:start position:0% +operators which are a X plus orus I a y +and a +us on a alpha gives a a + + + align:start position:0% +and a +us on a alpha gives a a + + + + align:start position:0% +and a +us on a alpha gives a a + +1us alpha alpha Plus or - 1 + + align:start position:0% +1us alpha alpha Plus or - 1 + + + align:start position:0% +1us alpha alpha Plus or - 1 +square a plus- + + align:start position:0% + + + + align:start position:0% + +1 and that's all that's all you + + align:start position:0% +1 and that's all that's all you + + + align:start position:0% +1 and that's all that's all you +need + + align:start position:0% +need + + + align:start position:0% +need +this is a you know a small amount to + + align:start position:0% +this is a you know a small amount to + + + align:start position:0% +this is a you know a small amount to +learn in order to be able to address + + align:start position:0% +learn in order to be able to address + + + align:start position:0% +learn in order to be able to address +practically any problem in diatomic + + align:start position:0% +practically any problem in diatomic + + + align:start position:0% +practically any problem in diatomic +molecule + + align:start position:0% +molecule + + + align:start position:0% +molecule +spectroscopy and the reason case a is + + align:start position:0% +spectroscopy and the reason case a is + + + align:start position:0% +spectroscopy and the reason case a is +nice + + align:start position:0% +nice + + + align:start position:0% +nice +is you have three important angular + + align:start position:0% +is you have three important angular + + + align:start position:0% +is you have three important angular +momentum and each of them have their + + align:start position:0% +momentum and each of them have their + + + align:start position:0% +momentum and each of them have their +projection + + align:start position:0% +projection + + + align:start position:0% +projection +specified so so that means it is + + align:start position:0% +specified so so that means it is + + + align:start position:0% +specified so so that means it is +completely transparent to write Matrix + + align:start position:0% +completely transparent to write Matrix + + + align:start position:0% +completely transparent to write Matrix +elements of a s a z and A+ minus there + + align:start position:0% +elements of a s a z and A+ minus there + + + align:start position:0% +elements of a s a z and A+ minus there +isn't anything + + align:start position:0% +isn't anything + + + align:start position:0% +isn't anything +else so you don't have to use CL Cordon + + align:start position:0% +else so you don't have to use CL Cordon + + + align:start position:0% +else so you don't have to use CL Cordon +coefficients or 3j + + align:start position:0% +coefficients or 3j + + + align:start position:0% +coefficients or 3j +coefficients if you're in case + + align:start position:0% +coefficients if you're in case + + + align:start position:0% +coefficients if you're in case +a so even for situations where case a is + + align:start position:0% +a so even for situations where case a is + + + align:start position:0% +a so even for situations where case a is +inappropriate many people prefer to use + + align:start position:0% +inappropriate many people prefer to use + + + align:start position:0% +inappropriate many people prefer to use +Cas a because there it's easy for them + + align:start position:0% +Cas a because there it's easy for them + + + align:start position:0% +Cas a because there it's easy for them +to set up the machine that represents + + align:start position:0% +to set up the machine that represents + + + align:start position:0% +to set up the machine that represents +their + + align:start position:0% + + + + align:start position:0% + +spect now there's no big deal using 3j + + align:start position:0% +spect now there's no big deal using 3j + + + align:start position:0% +spect now there's no big deal using 3j +coefficients to deal with angular + + align:start position:0% +coefficients to deal with angular + + + align:start position:0% +coefficients to deal with angular +momenta coupling and uncoupling and if + + align:start position:0% +momenta coupling and uncoupling and if + + + align:start position:0% +momenta coupling and uncoupling and if +you're going to be a professional you + + align:start position:0% +you're going to be a professional you + + + align:start position:0% +you're going to be a professional you +want to be able to work in different + + align:start position:0% +want to be able to work in different + + + align:start position:0% +want to be able to work in different +basis sets and to transform between them + + align:start position:0% +basis sets and to transform between them + + + align:start position:0% +basis sets and to transform between them +using + + align:start position:0% +using + + + align:start position:0% +using +the + + align:start position:0% +the + + + align:start position:0% +the +uh the vector coupling or 3j + + align:start position:0% +uh the vector coupling or 3j + + + align:start position:0% +uh the vector coupling or 3j +coefficients um and you can get a + + align:start position:0% +coefficients um and you can get a + + + align:start position:0% +coefficients um and you can get a +computer routine that will calculate any + + align:start position:0% +computer routine that will calculate any + + + align:start position:0% +computer routine that will calculate any +of those you ever need and so the only + + align:start position:0% +of those you ever need and so the only + + + align:start position:0% +of those you ever need and so the only +difficulty is that 3j coefficients are + + align:start position:0% +difficulty is that 3j coefficients are + + + align:start position:0% +difficulty is that 3j coefficients are +expressed angular momentum + + align:start position:0% +expressed angular momentum + + + align:start position:0% +expressed angular momentum +transformation coefficients are + + align:start position:0% +transformation coefficients are + + + align:start position:0% +transformation coefficients are +expressed or are labeled with six + + align:start position:0% +expressed or are labeled with six + + + align:start position:0% +expressed or are labeled with six +quantum + + align:start position:0% + + + + align:start position:0% + +numbers and so somehow you have to think + + align:start position:0% +numbers and so somehow you have to think + + + align:start position:0% +numbers and so somehow you have to think +about six quantum + + align:start position:0% +about six quantum + + + align:start position:0% +about six quantum +numbers + + align:start position:0% +numbers + + + align:start position:0% +numbers +and after a while it + + align:start position:0% +and after a while it + + + align:start position:0% +and after a while it +becomes not so hard + + align:start position:0% +becomes not so hard + + + align:start position:0% +becomes not so hard +but this this is a more linear approach + + align:start position:0% +but this this is a more linear approach + + + align:start position:0% +but this this is a more linear approach +in some sense okay so I said enough + + align:start position:0% +in some sense okay so I said enough + + + align:start position:0% +in some sense okay so I said enough +about that uh if you're going to start + + align:start position:0% +about that uh if you're going to start + + + align:start position:0% +about that uh if you're going to start +out doing uh datomic molecules I + + align:start position:0% +out doing uh datomic molecules I + + + align:start position:0% +out doing uh datomic molecules I +strongly recommend case + + align:start position:0% +strongly recommend case + + + align:start position:0% +strongly recommend case +a yes you remind us I can't remember is + + align:start position:0% +a yes you remind us I can't remember is + + + align:start position:0% +a yes you remind us I can't remember is +there any obvious way to to look at a + + align:start position:0% +there any obvious way to to look at a + + + align:start position:0% +there any obvious way to to look at a +datomic molecule and guess whether it's + + align:start position:0% +datomic molecule and guess whether it's + + + align:start position:0% +datomic molecule and guess whether it's +going to be case A or B is it has + + align:start position:0% +going to be case A or B is it has + + + align:start position:0% +going to be case A or B is it has +something to do with the size type of + + align:start position:0% +something to do with the size type of + + + align:start position:0% +something to do with the size type of +you have to look at + + align:start position:0% +you have to look at + + + align:start position:0% +you have to look at +the + + align:start position:0% +the + + + align:start position:0% +the +versus + + align:start position:0% +versus + + + align:start position:0% +versus +B uh + + align:start position:0% +B uh + + + align:start position:0% +B uh +J okay so all you have to know is this + + align:start position:0% +J okay so all you have to know is this + + + align:start position:0% +J okay so all you have to know is this +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +orbit the rotational Conant that's right + + align:start position:0% +orbit the rotational Conant that's right + + + align:start position:0% +orbit the rotational Conant that's right +and so a is small for the beginning of + + align:start position:0% +and so a is small for the beginning of + + + align:start position:0% +and so a is small for the beginning of +the periodic table it gets larger and + + align:start position:0% +the periodic table it gets larger and + + + align:start position:0% +the periodic table it gets larger and +larger and uh B uh is uh large for + + align:start position:0% +larger and uh B uh is uh large for + + + align:start position:0% +larger and uh B uh is uh large for +hydrogen and large for molecules that + + align:start position:0% +hydrogen and large for molecules that + + + align:start position:0% +hydrogen and large for molecules that +have one + + align:start position:0% +have one + + + align:start position:0% +have one +hydrogen and sort of intermediate for + + align:start position:0% +hydrogen and sort of intermediate for + + + align:start position:0% +hydrogen and sort of intermediate for +molecules that have two second row atoms + + align:start position:0% +molecules that have two second row atoms + + + align:start position:0% +molecules that have two second row atoms +like + + align:start position:0% +like + + + align:start position:0% +like +Co and uh for heavier atoms B is very + + align:start position:0% +Co and uh for heavier atoms B is very + + + align:start position:0% +Co and uh for heavier atoms B is very +small and so as you go down the periodic + + align:start position:0% +small and so as you go down the periodic + + + align:start position:0% +small and so as you go down the periodic +table a heavier heavier molecule + + align:start position:0% +table a heavier heavier molecule + + + align:start position:0% +table a heavier heavier molecule +you tend to go towards case + + align:start position:0% +you tend to go towards case + + + align:start position:0% +you tend to go towards case +a but if Lambda is zero in other words + + align:start position:0% +a but if Lambda is zero in other words + + + align:start position:0% +a but if Lambda is zero in other words +Sigma States you're always in + + align:start position:0% + + + + align:start position:0% + +KP but it's not a big + + align:start position:0% + + + + align:start position:0% + +deal okay now I said it was easy but + + align:start position:0% +deal okay now I said it was easy but + + + align:start position:0% +deal okay now I said it was easy but +there's one little patch if you want to + + align:start position:0% +there's one little patch if you want to + + + align:start position:0% +there's one little patch if you want to +do this without thinking you have to say + + align:start position:0% +do this without thinking you have to say + + + align:start position:0% +do this without thinking you have to say +oh + + align:start position:0% +oh + + + align:start position:0% +oh +uh Bob told me that if we have an + + align:start position:0% +uh Bob told me that if we have an + + + align:start position:0% +uh Bob told me that if we have an +angular momentum that controls the RO + + align:start position:0% +angular momentum that controls the RO + + + align:start position:0% +angular momentum that controls the RO +the rotation of the body fixed + + align:start position:0% +the rotation of the body fixed + + + align:start position:0% +the rotation of the body fixed +coordinate system relative to the + + align:start position:0% +coordinate system relative to the + + + align:start position:0% +coordinate system relative to the +laboratory coordinate + + align:start position:0% + + + + align:start position:0% + +system then I have to make a small patch + + align:start position:0% +system then I have to make a small patch + + + align:start position:0% +system then I have to make a small patch +and it turns out that + + align:start position:0% +and it turns out that + + + align:start position:0% +and it turns out that +j + + align:start position:0% +j + + + align:start position:0% +j +n and R J is the total angular momentum + + align:start position:0% +n and R J is the total angular momentum + + + align:start position:0% +n and R J is the total angular momentum +n is J minus s the total angular + + align:start position:0% +n is J minus s the total angular + + + align:start position:0% +n is J minus s the total angular +momentum exclusive of Spin and R is the + + align:start position:0% +momentum exclusive of Spin and R is the + + + align:start position:0% +momentum exclusive of Spin and R is the +nuclear + + align:start position:0% +nuclear + + + align:start position:0% +nuclear +rotation then J plus + + align:start position:0% +rotation then J plus + + + align:start position:0% +rotation then J plus +lowers Omega instead of raising + + align:start position:0% + + + + align:start position:0% + +it n plus lowers r+ well r+ can't really + + align:start position:0% +it n plus lowers r+ well r+ can't really + + + align:start position:0% +it n plus lowers r+ well r+ can't really +do anything because there is no + + align:start position:0% +do anything because there is no + + + align:start position:0% +do anything because there is no +projection of r on the inter nuclear + + align:start position:0% +projection of r on the inter nuclear + + + align:start position:0% +projection of r on the inter nuclear +axis because R is we have Atomic + + align:start position:0% +axis because R is we have Atomic + + + align:start position:0% +axis because R is we have Atomic +molecule and R by definition is + + align:start position:0% +molecule and R by definition is + + + align:start position:0% +molecule and R by definition is +perpendicular so but these angular + + align:start position:0% +perpendicular so but these angular + + + align:start position:0% +perpendicular so but these angular +moment have some special + + align:start position:0% +moment have some special + + + align:start position:0% +moment have some special +property and you can you can understand + + align:start position:0% +property and you can you can understand + + + align:start position:0% +property and you can you can understand +that when you look carefully at the + + align:start position:0% +that when you look carefully at the + + + align:start position:0% +that when you look carefully at the +transformation that takes you from body + + align:start position:0% +transformation that takes you from body + + + align:start position:0% +transformation that takes you from body +to + + align:start position:0% +to + + + align:start position:0% +to +laboratory Direction cosign and when you + + align:start position:0% +laboratory Direction cosign and when you + + + align:start position:0% +laboratory Direction cosign and when you +work when you develop more facility with + + align:start position:0% +work when you develop more facility with + + + align:start position:0% +work when you develop more facility with +the the true classical mechanics and one + + align:start position:0% +the the true classical mechanics and one + + + align:start position:0% +the the true classical mechanics and one +mechanics of the system okay but right + + align:start position:0% +mechanics of the system okay but right + + + align:start position:0% +mechanics of the system okay but right +now I just say this is a + + align:start position:0% +now I just say this is a + + + align:start position:0% +now I just say this is a +patch and basically you are now + + align:start position:0% +patch and basically you are now + + + align:start position:0% +patch and basically you are now +empowered to do all calculations on + + align:start position:0% +empowered to do all calculations on + + + align:start position:0% +empowered to do all calculations on +datomic + + align:start position:0% +datomic + + + align:start position:0% +datomic +molecules at least as far as the angular + + align:start position:0% +molecules at least as far as the angular + + + align:start position:0% +molecules at least as far as the angular +meor are + + align:start position:0% +meor are + + + align:start position:0% +meor are +concerned okay now if you want to deal + + align:start position:0% +concerned okay now if you want to deal + + + align:start position:0% +concerned okay now if you want to deal +with the nuclear + + align:start position:0% +with the nuclear + + + align:start position:0% +with the nuclear +motion that's another topic which I will + + align:start position:0% +motion that's another topic which I will + + + align:start position:0% +motion that's another topic which I will +address okay so now I make a little + + align:start position:0% +address okay so now I make a little + + + align:start position:0% +address okay so now I make a little +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +table of all the angular momenta you're + + align:start position:0% +table of all the angular momenta you're + + + align:start position:0% +table of all the angular momenta you're +likely to + + align:start position:0% +likely to + + + align:start position:0% +likely to +encounter well a lot of them many is so + + align:start position:0% +encounter well a lot of them many is so + + + align:start position:0% +encounter well a lot of them many is so +we have the + + align:start position:0% + + + + align:start position:0% + +operator the quantum + + align:start position:0% +operator the quantum + + + align:start position:0% +operator the quantum +number and the + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +selction so + + align:start position:0% + + + + align:start position:0% + +j + + align:start position:0% +j + + + align:start position:0% +j +s j z J + + align:start position:0% +s j z J + + + align:start position:0% +s j z J +plusus I'm not going to be able to do + + align:start position:0% +plusus I'm not going to be able to do + + + align:start position:0% +plusus I'm not going to be able to do +this all on one board but you'll get the + + align:start position:0% +this all on one board but you'll get the + + + align:start position:0% +this all on one board but you'll get the +idea so operators are generally + + align:start position:0% +idea so operators are generally + + + align:start position:0% +idea so operators are generally +represented as a bold face oops + + align:start position:0% +represented as a bold face oops + + + align:start position:0% +represented as a bold face oops +plus + + align:start position:0% +plus + + + align:start position:0% +plus +um J has two projection quantum numbers + + align:start position:0% +um J has two projection quantum numbers + + + align:start position:0% +um J has two projection quantum numbers +one in the laboratory and one in the + + align:start position:0% +one in the laboratory and one in the + + + align:start position:0% +one in the laboratory and one in the +body and so I've chosen to use the Su + + align:start position:0% +body and so I've chosen to use the Su + + + align:start position:0% +body and so I've chosen to use the Su +superscript for body and subscript for + + align:start position:0% +superscript for body and subscript for + + + align:start position:0% +superscript for body and subscript for +laboratory you encounter that less often + + align:start position:0% +laboratory you encounter that less often + + + align:start position:0% +laboratory you encounter that less often +uh and so I'm not even going to talk + + align:start position:0% +uh and so I'm not even going to talk + + + align:start position:0% +uh and so I'm not even going to talk +about it so we have the quantum number + + align:start position:0% +about it so we have the quantum number + + + align:start position:0% +about it so we have the quantum number +is J and for JJ for J squ you get JJ + + + align:start position:0% +is J and for JJ for J squ you get JJ + + + + align:start position:0% +is J and for JJ for J squ you get JJ + +one and quantum number are generally + + align:start position:0% +one and quantum number are generally + + + align:start position:0% +one and quantum number are generally +written as I tell + + align:start position:0% + + + + align:start position:0% + +it the selection rule for j s is Delta = + + align:start position:0% +it the selection rule for j s is Delta = + + + align:start position:0% +it the selection rule for j s is Delta = +0 Delta Omega = 0 the quantum number for + + align:start position:0% +0 Delta Omega = 0 the quantum number for + + + align:start position:0% +0 Delta Omega = 0 the quantum number for +JZ is + + align:start position:0% +JZ is + + + align:start position:0% +JZ is +Omega Delta J + + align:start position:0% +Omega Delta J + + + align:start position:0% +Omega Delta J += + + align:start position:0% + + + + align:start position:0% + +delega there's no quantum number for + + align:start position:0% +delega there's no quantum number for + + + align:start position:0% +delega there's no quantum number for +this operator because it's an off + + align:start position:0% +this operator because it's an off + + + align:start position:0% +this operator because it's an off +diagonal + + align:start position:0% +diagonal + + + align:start position:0% +diagonal +operator and the selection R is Delta j + + align:start position:0% +operator and the selection R is Delta j + + + align:start position:0% +operator and the selection R is Delta j += 0 Delta + + align:start position:0% += 0 Delta + + + align:start position:0% += 0 Delta +Omega = minus or + + + align:start position:0% + + + + align:start position:0% + +one similarly for s² s z and S + + align:start position:0% +one similarly for s² s z and S + + + align:start position:0% +one similarly for s² s z and S ++ s s + + align:start position:0% ++ s s + + + align:start position:0% ++ s s ++1 + + align:start position:0% + + + + align:start position:0% + +Sigma Delta S = 0 Delta Sigma = 0 Delta + + align:start position:0% +Sigma Delta S = 0 Delta Sigma = 0 Delta + + + align:start position:0% +Sigma Delta S = 0 Delta Sigma = 0 Delta +Sigma S = 0 Delta Sigma = 0 Delta S = 0 + + align:start position:0% +Sigma S = 0 Delta Sigma = 0 Delta S = 0 + + + align:start position:0% +Sigma S = 0 Delta Sigma = 0 Delta S = 0 +Delta + + align:start position:0% +Delta + + + align:start position:0% +Delta +Sigma + + align:start position:0% +Sigma + + + align:start position:0% +Sigma +and we can go on for a long + + align:start position:0% + + + + align:start position:0% + +time now we come to + + align:start position:0% +time now we come to + + + align:start position:0% +time now we come to +l or l squ because a molecule isn't + + align:start position:0% +l or l squ because a molecule isn't + + + align:start position:0% +l or l squ because a molecule isn't +spherical L is usually not + + align:start position:0% +spherical L is usually not + + + align:start position:0% +spherical L is usually not +defined but we can still Define out Z + + align:start position:0% +defined but we can still Define out Z + + + align:start position:0% +defined but we can still Define out Z +and we can still use l+ + + align:start position:0% +and we can still use l+ + + + align:start position:0% +and we can still use l+ +minus so we don't have a quantum number + + align:start position:0% +minus so we don't have a quantum number + + + align:start position:0% +minus so we don't have a quantum number +here although we'd like to write LL + + + align:start position:0% +here although we'd like to write LL + + + + align:start position:0% +here although we'd like to write LL + +one and we we don't have a a qualum + + align:start position:0% +one and we we don't have a a qualum + + + align:start position:0% +one and we we don't have a a qualum +number for a selection rule for L + + align:start position:0% +number for a selection rule for L + + + align:start position:0% +number for a selection rule for L +because we don't know what L is but we + + align:start position:0% +because we don't know what L is but we + + + align:start position:0% +because we don't know what L is but we +still have Delta Lambda equals z and + + align:start position:0% +still have Delta Lambda equals z and + + + align:start position:0% +still have Delta Lambda equals z and +here we still have Delta Lambda equal Z + + align:start position:0% +here we still have Delta Lambda equal Z + + + align:start position:0% +here we still have Delta Lambda equal Z +and here we have Delta + + align:start position:0% +and here we have Delta + + + align:start position:0% +and here we have Delta +Lambda plus orus + + align:start position:0% + + + + align:start position:0% + +one there are other quantum numbers like + + align:start position:0% +one there are other quantum numbers like + + + align:start position:0% +one there are other quantum numbers like +or operators like n which is J - + + align:start position:0% + + + + align:start position:0% + +s + + align:start position:0% +s + + + align:start position:0% +s +and it turns out that n + + align:start position:0% +and it turns out that n + + + align:start position:0% +and it turns out that n +z has the quantum number + + align:start position:0% +z has the quantum number + + + align:start position:0% +z has the quantum number +Lambda because NZ is identical to + + align:start position:0% +Lambda because NZ is identical to + + + align:start position:0% +Lambda because NZ is identical to +LZ as far as the part that can have uh a + + align:start position:0% +LZ as far as the part that can have uh a + + + align:start position:0% +LZ as far as the part that can have uh a +projection because + + align:start position:0% +projection because + + + align:start position:0% +projection because +NZ uh + + align:start position:0% +NZ uh + + + align:start position:0% +NZ uh +um we I mean JZ is LZ plus SZ plus RZ RZ + + align:start position:0% +um we I mean JZ is LZ plus SZ plus RZ RZ + + + align:start position:0% +um we I mean JZ is LZ plus SZ plus RZ RZ +the projection of the nuclear rotation + + align:start position:0% +the projection of the nuclear rotation + + + align:start position:0% +the projection of the nuclear rotation +on the inter nuclear axis is has to be + + align:start position:0% +on the inter nuclear axis is has to be + + + align:start position:0% +on the inter nuclear axis is has to be +zero and so uh JZ minus uh JZ minus SZ + + align:start position:0% +zero and so uh JZ minus uh JZ minus SZ + + + align:start position:0% +zero and so uh JZ minus uh JZ minus SZ +is LZ + + align:start position:0% +is LZ + + + align:start position:0% +is LZ +so LZ is + + align:start position:0% +so LZ is + + + align:start position:0% +so LZ is +NZ uh okay now we get to more esoteric + + align:start position:0% +NZ uh okay now we get to more esoteric + + + align:start position:0% +NZ uh okay now we get to more esoteric +situations uh but I want to talk about + + align:start position:0% +situations uh but I want to talk about + + + align:start position:0% +situations uh but I want to talk about +them suppose you have a + + align:start position:0% +them suppose you have a + + + align:start position:0% +them suppose you have a +molecule uh which has sort of a a a + + align:start position:0% +molecule uh which has sort of a a a + + + align:start position:0% +molecule uh which has sort of a a a +closed shell or nearly close shell core + + align:start position:0% +closed shell or nearly close shell core + + + align:start position:0% +closed shell or nearly close shell core +an electron far away from it and so this + + align:start position:0% +an electron far away from it and so this + + + align:start position:0% +an electron far away from it and so this +is an ion + + align:start position:0% +is an ion + + + align:start position:0% +is an ion +and this is called a redberg + + align:start position:0% + + + + align:start position:0% + +state when the electron is far away from + + align:start position:0% +state when the electron is far away from + + + align:start position:0% +state when the electron is far away from +the ion it thinks it's on an atom and we + + align:start position:0% +the ion it thinks it's on an atom and we + + + align:start position:0% +the ion it thinks it's on an atom and we +get L back so but we get not Big L but + + align:start position:0% +get L back so but we get not Big L but + + + align:start position:0% +get L back so but we get not Big L but +little L the L for this rer + + align:start position:0% +little L the L for this rer + + + align:start position:0% +little L the L for this rer +electron and so we start having more + + align:start position:0% +electron and so we start having more + + + align:start position:0% +electron and so we start having more +quantum numbers we have the quantum + + align:start position:0% +quantum numbers we have the quantum + + + align:start position:0% +quantum numbers we have the quantum +numbers associated with all of the + + align:start position:0% +numbers associated with all of the + + + align:start position:0% +numbers associated with all of the +angular momentum of the + + align:start position:0% + + + + align:start position:0% + +ion and you have the quantum numbers + + align:start position:0% +ion and you have the quantum numbers + + + align:start position:0% +ion and you have the quantum numbers +associated with the + + align:start position:0% +associated with the + + + align:start position:0% +associated with the +rber so instead of + + align:start position:0% +rber so instead of + + + align:start position:0% +rber so instead of +having uh just + + align:start position:0% +having uh just + + + align:start position:0% +having uh just +some uh L S and J as our quantum numbers + + align:start position:0% +some uh L S and J as our quantum numbers + + + align:start position:0% +some uh L S and J as our quantum numbers +we start having six quantum numbers we + + align:start position:0% +we start having six quantum numbers we + + + align:start position:0% +we start having six quantum numbers we +have L plus S Plus and j+ and little L + + align:start position:0% +have L plus S Plus and j+ and little L + + + align:start position:0% +have L plus S Plus and j+ and little L +little + + align:start position:0% +little + + + align:start position:0% +little +s uh and Little J or something like that + + align:start position:0% +s uh and Little J or something like that + + + align:start position:0% +s uh and Little J or something like that +so we still can couple them together we + + align:start position:0% +so we still can couple them together we + + + align:start position:0% +so we still can couple them together we +can still use case a + + align:start position:0% +can still use case a + + + align:start position:0% +can still use case a +methods uh and so we we can have + + align:start position:0% +methods uh and so we we can have + + + align:start position:0% +methods uh and so we we can have +j+ now this is not the raising or + + align:start position:0% +j+ now this is not the raising or + + + align:start position:0% +j+ now this is not the raising or +lowering operator this is J for the ion + + align:start position:0% +lowering operator this is J for the ion + + + align:start position:0% +lowering operator this is J for the ion +we use plus and you can tell the + + align:start position:0% +we use plus and you can tell the + + + align:start position:0% +we use plus and you can tell the +difference because when you have a bold + + align:start position:0% + + + + align:start position:0% + +operator a bold symbol it's an + + align:start position:0% + + + + align:start position:0% + +operator and when you have an italic + + align:start position:0% +operator and when you have an italic + + + align:start position:0% +operator and when you have an italic +symbol uh it's a quantum number and so + + align:start position:0% +symbol uh it's a quantum number and so + + + align:start position:0% +symbol uh it's a quantum number and so +uh and when there's a problem uh when + + align:start position:0% +uh and when there's a problem uh when + + + align:start position:0% +uh and when there's a problem uh when +you have an operator and you want raing + + align:start position:0% +you have an operator and you want raing + + + align:start position:0% +you have an operator and you want raing +and lowering operators a bit and you + + align:start position:0% +and lowering operators a bit and you + + + align:start position:0% +and lowering operators a bit and you +put okay and so uh we would uh we would + + align:start position:0% +put okay and so uh we would uh we would + + + align:start position:0% +put okay and so uh we would uh we would +the the quantum numbers associated with + + align:start position:0% +the the quantum numbers associated with + + + align:start position:0% +the the quantum numbers associated with +uh the projection + + align:start position:0% +uh the projection + + + align:start position:0% +uh the projection +okay so suppose we have the J + + + align:start position:0% +okay so suppose we have the J + + + + align:start position:0% +okay so suppose we have the J + +z that would be called Omega plus the + + align:start position:0% +z that would be called Omega plus the + + + align:start position:0% +z that would be called Omega plus the +quantum number okay this is more + + align:start position:0% +quantum number okay this is more + + + align:start position:0% +quantum number okay this is more +detailed than you + + align:start position:0% +detailed than you + + + align:start position:0% +detailed than you +need okay so we have we just put a Plus + + align:start position:0% +need okay so we have we just put a Plus + + + align:start position:0% +need okay so we have we just put a Plus +on the quantum numbers for the ion and + + align:start position:0% +on the quantum numbers for the ion and + + + align:start position:0% +on the quantum numbers for the ion and +since this is a one electron quantity we + + align:start position:0% +since this is a one electron quantity we + + + align:start position:0% +since this is a one electron quantity we +use lowercase letters Little J little L + + align:start position:0% +use lowercase letters Little J little L + + + align:start position:0% +use lowercase letters Little J little L +little + + align:start position:0% +little + + + align:start position:0% +little +s little little Omega lowercase Omega + + align:start position:0% +s little little Omega lowercase Omega + + + align:start position:0% +s little little Omega lowercase Omega +lowercase Lambda lowercase Sigma for the + + align:start position:0% +lowercase Lambda lowercase Sigma for the + + + align:start position:0% +lowercase Lambda lowercase Sigma for the +quantum numbers of the + + align:start position:0% +quantum numbers of the + + + align:start position:0% +quantum numbers of the +electron so there isn't any ambiguity + + align:start position:0% +electron so there isn't any ambiguity + + + align:start position:0% +electron so there isn't any ambiguity +there's lots of angular momenta and + + align:start position:0% +there's lots of angular momenta and + + + align:start position:0% +there's lots of angular momenta and +there's lots of coupling cases remember + + align:start position:0% +there's lots of coupling cases remember + + + align:start position:0% +there's lots of coupling cases remember +when we talked about the coupling cases + + align:start position:0% +when we talked about the coupling cases + + + align:start position:0% +when we talked about the coupling cases +last time I said we had three turns + + align:start position:0% +last time I said we had three turns + + + align:start position:0% +last time I said we had three turns +electronic spit orbit and rotation and + + align:start position:0% +electronic spit orbit and rotation and + + + align:start position:0% +electronic spit orbit and rotation and +we can arras them in + + align:start position:0% +we can arras them in + + + align:start position:0% +we can arras them in +six orders of relative size and that + + align:start position:0% +six orders of relative size and that + + + align:start position:0% +six orders of relative size and that +leads to the five known Hood coupling + + align:start position:0% +leads to the five known Hood coupling + + + align:start position:0% +leads to the five known Hood coupling +cases and one other but now if we have + + align:start position:0% +cases and one other but now if we have + + + align:start position:0% +cases and one other but now if we have +more quantum + + align:start position:0% +more quantum + + + align:start position:0% +more quantum +numbers you can imagine how many + + align:start position:0% +numbers you can imagine how many + + + align:start position:0% +numbers you can imagine how many +coupling cases there + + align:start position:0% +coupling cases there + + + align:start position:0% +coupling cases there +are but it's no big deal because the + + align:start position:0% +are but it's no big deal because the + + + align:start position:0% +are but it's no big deal because the +same techniques you use to evaluate the + + align:start position:0% +same techniques you use to evaluate the + + + align:start position:0% +same techniques you use to evaluate the +Matrix elements and rearrange terms of + + align:start position:0% +Matrix elements and rearrange terms of + + + align:start position:0% +Matrix elements and rearrange terms of +the Hiltonia there's nothing different + + align:start position:0% +the Hiltonia there's nothing different + + + align:start position:0% +the Hiltonia there's nothing different +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so you are empowered to deal with + + align:start position:0% +so you are empowered to deal with + + + align:start position:0% +so you are empowered to deal with +angular and diatomic molecules even if + + align:start position:0% +angular and diatomic molecules even if + + + align:start position:0% +angular and diatomic molecules even if +we have six rather than three important + + align:start position:0% +we have six rather than three important + + + align:start position:0% +we have six rather than three important +angular + + align:start position:0% + + + + align:start position:0% + +moment so what's what's left well + + align:start position:0% +moment so what's what's left well + + + align:start position:0% +moment so what's what's left well +there's the vibrational + + align:start position:0% +there's the vibrational + + + align:start position:0% +there's the vibrational +equ and let's talk about them and I'm + + align:start position:0% +equ and let's talk about them and I'm + + + align:start position:0% +equ and let's talk about them and I'm +going + + align:start position:0% +going + + + align:start position:0% +going +to present a very very important + + align:start position:0% +to present a very very important + + + align:start position:0% +to present a very very important +approximation that enables us to uh + + align:start position:0% +approximation that enables us to uh + + + align:start position:0% +approximation that enables us to uh +simplify our work dealing with + + align:start position:0% +simplify our work dealing with + + + align:start position:0% +simplify our work dealing with +vibrational + + align:start position:0% +vibrational + + + align:start position:0% +vibrational +matrixes okay so the vibrational wave + + align:start position:0% +matrixes okay so the vibrational wave + + + align:start position:0% +matrixes okay so the vibrational wave +function we have that should be a Kai we + + align:start position:0% +function we have that should be a Kai we + + + align:start position:0% +function we have that should be a Kai we +have a vibrational wave function for the + + align:start position:0% +have a vibrational wave function for the + + + align:start position:0% +have a vibrational wave function for the +I electronic State and then it's got a + + align:start position:0% +I electronic State and then it's got a + + + align:start position:0% +I electronic State and then it's got a +vibrational qu is the function of + + align:start position:0% +vibrational qu is the function of + + + align:start position:0% +vibrational qu is the function of +r in direct notation that object is the + + align:start position:0% +r in direct notation that object is the + + + align:start position:0% +r in direct notation that object is the +same thing as + + align:start position:0% +same thing as + + + align:start position:0% +same thing as +this okay uh we tend to like to think of + + align:start position:0% +this okay uh we tend to like to think of + + + align:start position:0% +this okay uh we tend to like to think of +vibrational wave functions as functions + + align:start position:0% +vibrational wave functions as functions + + + align:start position:0% +vibrational wave functions as functions +and angular momentum wave functions is + + align:start position:0% +and angular momentum wave functions is + + + align:start position:0% +and angular momentum wave functions is +vectors because we don't what I + + align:start position:0% +vectors because we don't what I + + + align:start position:0% +vectors because we don't what I +mean this is a simple one-dimensional + + align:start position:0% +mean this is a simple one-dimensional + + + align:start position:0% +mean this is a simple one-dimensional +function and we're going to be + + align:start position:0% +function and we're going to be + + + align:start position:0% +function and we're going to be +calculating integrals over it there + + align:start position:0% +calculating integrals over it there + + + align:start position:0% +calculating integrals over it there +aren't nice uh angular momentum like + + align:start position:0% +aren't nice uh angular momentum like + + + align:start position:0% +aren't nice uh angular momentum like +algebra for vibrational weight + + align:start position:0% +algebra for vibrational weight + + + align:start position:0% +algebra for vibrational weight +functions whereas angular momentum wave + + align:start position:0% +functions whereas angular momentum wave + + + align:start position:0% +functions whereas angular momentum wave +functions are treated by an algebra + + align:start position:0% +functions are treated by an algebra + + + align:start position:0% +functions are treated by an algebra +where basically all the Matrix elements + + align:start position:0% +where basically all the Matrix elements + + + align:start position:0% +where basically all the Matrix elements +are directly evaluated and you never + + align:start position:0% +are directly evaluated and you never + + + align:start position:0% +are directly evaluated and you never +look at the differential operators that + + align:start position:0% +look at the differential operators that + + + align:start position:0% +look at the differential operators that +correspond to the angular momentum nor + + align:start position:0% +correspond to the angular momentum nor + + + align:start position:0% +correspond to the angular momentum nor +the forms of the wave + + align:start position:0% +the forms of the wave + + + align:start position:0% +the forms of the wave +functions so it + + align:start position:0% +functions so it + + + align:start position:0% +functions so it +is tempting to look at these sorts of + + align:start position:0% +is tempting to look at these sorts of + + + align:start position:0% +is tempting to look at these sorts of +things rather than this kind of a symbol + + align:start position:0% +things rather than this kind of a symbol + + + align:start position:0% +things rather than this kind of a symbol +for vibration + + align:start position:0% + + + + align:start position:0% + +now we have a wave function which is a + + align:start position:0% +now we have a wave function which is a + + + align:start position:0% +now we have a wave function which is a +product of an electronic vibrational and + + align:start position:0% +product of an electronic vibrational and + + + align:start position:0% +product of an electronic vibrational and +a rotational part so in order to + + align:start position:0% +a rotational part so in order to + + + align:start position:0% +a rotational part so in order to +calculate Matrix elements we're always + + align:start position:0% +calculate Matrix elements we're always + + + align:start position:0% +calculate Matrix elements we're always +going to be + + align:start position:0% +going to be + + + align:start position:0% +going to be +evaluating uh a product of three factors + + align:start position:0% +evaluating uh a product of three factors + + + align:start position:0% +evaluating uh a product of three factors +a rotational Matrix element a + + align:start position:0% +a rotational Matrix element a + + + align:start position:0% +a rotational Matrix element a +vibrational Matrix element and + + align:start position:0% +vibrational Matrix element and + + + align:start position:0% +vibrational Matrix element and +electronic Matrix + + align:start position:0% +electronic Matrix + + + align:start position:0% +electronic Matrix +element so the electronic + + align:start position:0% + + + + align:start position:0% + +part we deal with first + + align:start position:0% +part we deal with first + + + align:start position:0% +part we deal with first +because uh we get rid of it almost + + align:start position:0% +because uh we get rid of it almost + + + align:start position:0% +because uh we get rid of it almost +immediately so we have some electronic + + align:start position:0% +immediately so we have some electronic + + + align:start position:0% +immediately so we have some electronic +operator and we have two different + + align:start position:0% +operator and we have two different + + + align:start position:0% +operator and we have two different +electronic + + align:start position:0% +electronic + + + align:start position:0% +electronic +States and according to the Bourn + + align:start position:0% +States and according to the Bourn + + + align:start position:0% +States and according to the Bourn +Oppenheimer + + align:start position:0% +Oppenheimer + + + align:start position:0% +Oppenheimer +approximation these functions are + + align:start position:0% +approximation these functions are + + + align:start position:0% +approximation these functions are +parametric functions of internuclear + + align:start position:0% +parametric functions of internuclear + + + align:start position:0% +parametric functions of internuclear +distance so that means that we're going + + align:start position:0% +distance so that means that we're going + + + align:start position:0% +distance so that means that we're going +to have this Matrix element is going to + + align:start position:0% + + + + align:start position:0% + +be a function an implicit function of r + + align:start position:0% + + + + align:start position:0% + +inter so the borop says well we do the + + align:start position:0% +inter so the borop says well we do the + + + align:start position:0% +inter so the borop says well we do the +electronic integral it will be a number + + align:start position:0% +electronic integral it will be a number + + + align:start position:0% +electronic integral it will be a number +but this number will probably weakly + + align:start position:0% +but this number will probably weakly + + + align:start position:0% +but this number will probably weakly +depend on + + align:start position:0% +depend on + + + align:start position:0% +depend on +R + + align:start position:0% +R + + + align:start position:0% +R +now if this operator has an explicit + + align:start position:0% +now if this operator has an explicit + + + align:start position:0% +now if this operator has an explicit +dependence on r that also appear here + + align:start position:0% +dependence on r that also appear here + + + align:start position:0% +dependence on r that also appear here +now one operator that has an explicit + + align:start position:0% +now one operator that has an explicit + + + align:start position:0% +now one operator that has an explicit +dependence on R is the rotational + + align:start position:0% +dependence on R is the rotational + + + align:start position:0% +dependence on R is the rotational +constant HR S 2 u r + + align:start position:0% +constant HR S 2 u r + + + align:start position:0% +constant HR S 2 u r +s now that's not an electronic + + align:start position:0% +s now that's not an electronic + + + align:start position:0% +s now that's not an electronic +operator but so we're often going to + + align:start position:0% +operator but so we're often going to + + + align:start position:0% +operator but so we're often going to +have things that either implicitly or + + align:start position:0% +have things that either implicitly or + + + align:start position:0% +have things that either implicitly or +explicitly depend on intern includ + + align:start position:0% + + + + align:start position:0% + +distance this is a problem + + align:start position:0% +distance this is a problem + + + align:start position:0% +distance this is a problem +because when we have an electronic + + align:start position:0% +because when we have an electronic + + + align:start position:0% +because when we have an electronic +property that depends on our and we want + + align:start position:0% +property that depends on our and we want + + + align:start position:0% +property that depends on our and we want +to evaluate Matrix elements now I am uh + + align:start position:0% +to evaluate Matrix elements now I am uh + + + align:start position:0% +to evaluate Matrix elements now I am uh +writing the vibrational wave functions + + align:start position:0% +writing the vibrational wave functions + + + align:start position:0% +writing the vibrational wave functions +as as bro and KS + + align:start position:0% + + + + align:start position:0% + +here so this is a vibrational Matrix + + align:start position:0% +here so this is a vibrational Matrix + + + align:start position:0% +here so this is a vibrational Matrix +once we've done the electronic integral + + align:start position:0% +once we've done the electronic integral + + + align:start position:0% +once we've done the electronic integral +now we have to do the vibration + + align:start position:0% +now we have to do the vibration + + + align:start position:0% +now we have to do the vibration +interval if this is a function of our we + + align:start position:0% +interval if this is a function of our we + + + align:start position:0% +interval if this is a function of our we +got B + + align:start position:0% + + + + align:start position:0% + +problems we like to ignore the + + align:start position:0% +problems we like to ignore the + + + align:start position:0% +problems we like to ignore the +dependence on + + align:start position:0% +dependence on + + + align:start position:0% +dependence on +R + + align:start position:0% + + + + align:start position:0% + +so how bad is this how bad a problem is + + align:start position:0% +so how bad is this how bad a problem is + + + align:start position:0% +so how bad is this how bad a problem is +this well one can always expand this as + + align:start position:0% +this well one can always expand this as + + + align:start position:0% +this well one can always expand this as +a power Series in + + align:start position:0% +a power Series in + + + align:start position:0% +a power Series in +R and then evaluate all the necessary + + align:start position:0% +R and then evaluate all the necessary + + + align:start position:0% +R and then evaluate all the necessary +integrals so that would mean we have + + align:start position:0% +integrals so that would mean we have + + + align:start position:0% +integrals so that would mean we have +have uh things like just the vibrational + + align:start position:0% +have uh things like just the vibrational + + + align:start position:0% +have uh things like just the vibrational +overlap we'd have v r + + align:start position:0% +overlap we'd have v r + + + align:start position:0% +overlap we'd have v r +VJ we'd have VI R 2 + + align:start position:0% +VJ we'd have VI R 2 + + + align:start position:0% +VJ we'd have VI R 2 +VJ we'd have to calculate lots and + + align:start position:0% +VJ we'd have to calculate lots and + + + align:start position:0% +VJ we'd have to calculate lots and +lots of + + align:start position:0% +lots of + + + align:start position:0% +lots of +vibrational Matrix + + align:start position:0% +vibrational Matrix + + + align:start position:0% +vibrational Matrix +elements and this would be inconvenient + + align:start position:0% +elements and this would be inconvenient + + + align:start position:0% +elements and this would be inconvenient +and it would also be costly in terms of + + align:start position:0% +and it would also be costly in terms of + + + align:start position:0% +and it would also be costly in terms of +our understanding of the problem + + align:start position:0% +our understanding of the problem + + + align:start position:0% +our understanding of the problem +and so we'd like to make that go + + align:start position:0% + + + + align:start position:0% + +away so it turns + + align:start position:0% +away so it turns + + + align:start position:0% +away so it turns +out that we can + + align:start position:0% + + + + align:start position:0% + +always or almost always replace this + + align:start position:0% +always or almost always replace this + + + align:start position:0% +always or almost always replace this +kind of an integral with VI VJ a simple + + align:start position:0% +kind of an integral with VI VJ a simple + + + align:start position:0% +kind of an integral with VI VJ a simple +vibrational + + align:start position:0% +vibrational + + + align:start position:0% +vibrational +overlap times o i j of r v i VJ r + + align:start position:0% +overlap times o i j of r v i VJ r + + + align:start position:0% +overlap times o i j of r v i VJ r +that's called the r + + align:start position:0% +that's called the r + + + align:start position:0% +that's called the r +centroid the r + + align:start position:0% +centroid the r + + + align:start position:0% +centroid the r +centroid is + + align:start position:0% + + + + align:start position:0% + +defined + + align:start position:0% + + + + align:start position:0% + +as it's this quantity The Matrix element + + align:start position:0% +as it's this quantity The Matrix element + + + align:start position:0% +as it's this quantity The Matrix element +of r divided by the overlapping + + align:start position:0% +of r divided by the overlapping + + + align:start position:0% +of r divided by the overlapping +that's perfectly reasonable it it is the + + align:start position:0% +that's perfectly reasonable it it is the + + + align:start position:0% +that's perfectly reasonable it it is the +way you would Define the average value + + align:start position:0% +way you would Define the average value + + + align:start position:0% +way you would Define the average value +of + + align:start position:0% + + + + align:start position:0% + +R so the r centroid this is the r + + align:start position:0% +R so the r centroid this is the r + + + align:start position:0% +R so the r centroid this is the r +centroid the r centroid approximation + + align:start position:0% +centroid the r centroid approximation + + + align:start position:0% +centroid the r centroid approximation +says + + align:start position:0% +says + + + align:start position:0% +says +replace this integral of the function of + + align:start position:0% +replace this integral of the function of + + + align:start position:0% +replace this integral of the function of +r by the overlap integral the only + + align:start position:0% +r by the overlap integral the only + + + align:start position:0% +r by the overlap integral the only +vibrational integral you're going to + + align:start position:0% +vibrational integral you're going to + + + align:start position:0% +vibrational integral you're going to +have to calculate + + align:start position:0% +have to calculate + + + align:start position:0% +have to calculate +we not the only one times the r centroid + + align:start position:0% +we not the only one times the r centroid + + + align:start position:0% +we not the only one times the r centroid +this o of the r centroid instead of O of + + align:start position:0% + + + + align:start position:0% + +R that's an approximation it's a very + + align:start position:0% +R that's an approximation it's a very + + + align:start position:0% +R that's an approximation it's a very +good + + align:start position:0% +good + + + align:start position:0% +good +approximation and it's based on the + + align:start position:0% +approximation and it's based on the + + + align:start position:0% +approximation and it's based on the +assumption that r r v i VJ is equal to r + + align:start position:0% +assumption that r r v i VJ is equal to r + + + align:start position:0% +assumption that r r v i VJ is equal to r +n r e + + align:start position:0% +n r e + + + align:start position:0% +n r e +DJ over r nus1 e + + align:start position:0% +DJ over r nus1 e + + + align:start position:0% +DJ over r nus1 e +DJ this is the r centroid + + align:start position:0% +DJ this is the r centroid + + + align:start position:0% +DJ this is the r centroid +approximation the r centroid is this is + + align:start position:0% +approximation the r centroid is this is + + + align:start position:0% +approximation the r centroid is this is +given by any value of any power of n + + align:start position:0% +given by any value of any power of n + + + align:start position:0% +given by any value of any power of n +this ratio n n minus + + align:start position:0% +this ratio n n minus + + + align:start position:0% +this ratio n n minus +one now why should that be + + align:start position:0% + + + + align:start position:0% + +true + + align:start position:0% +true + + + align:start position:0% +true +it's astonishingly + + align:start position:0% + + + + align:start position:0% + +true how can we + + align:start position:0% +true how can we + + + align:start position:0% +true how can we +expect vibrational integrals involving + + align:start position:0% +expect vibrational integrals involving + + + align:start position:0% +expect vibrational integrals involving +different powers of R to have this + + align:start position:0% + + + + align:start position:0% + +property this gives us a hint of + + align:start position:0% +property this gives us a hint of + + + align:start position:0% +property this gives us a hint of +something that's going to be really + + align:start position:0% +something that's going to be really + + + align:start position:0% +something that's going to be really +important the + + align:start position:0% +important the + + + align:start position:0% +important the +integrals + + align:start position:0% +integrals + + + align:start position:0% +integrals +accumulate all always in a very narrow + + align:start position:0% +accumulate all always in a very narrow + + + align:start position:0% +accumulate all always in a very narrow +range of + + align:start position:0% + + + + align:start position:0% + +art that's called the stationary phase + + align:start position:0% + + + + align:start position:0% + +approximation and we'll get to that but + + align:start position:0% +approximation and we'll get to that but + + + align:start position:0% +approximation and we'll get to that but +that leads to really important + + align:start position:0% +that leads to really important + + + align:start position:0% +that leads to really important +simplifications because + + align:start position:0% +simplifications because + + + align:start position:0% +simplifications because +often one can + + align:start position:0% +often one can + + + align:start position:0% +often one can +know + + align:start position:0% +know + + + align:start position:0% +know +explicitly what region narrow region of + + align:start position:0% +explicitly what region narrow region of + + + align:start position:0% +explicitly what region narrow region of +internuclear a distance the integral + + align:start position:0% +internuclear a distance the integral + + + align:start position:0% +internuclear a distance the integral +will accumulate + + align:start position:0% +will accumulate + + + align:start position:0% +will accumulate +it for example if we have a problem like + + align:start position:0% +it for example if we have a problem like + + + align:start position:0% +it for example if we have a problem like +this where we have two potential + + align:start position:0% +this where we have two potential + + + align:start position:0% +this where we have two potential +curves and they cross and we want to + + align:start position:0% +curves and they cross and we want to + + + align:start position:0% +curves and they cross and we want to +calculate the vibration overlap between + + align:start position:0% +calculate the vibration overlap between + + + align:start position:0% +calculate the vibration overlap between +these two levels at about the same + + align:start position:0% +these two levels at about the same + + + align:start position:0% +these two levels at about the same +energy they integral the vibrational + + align:start position:0% +energy they integral the vibrational + + + align:start position:0% +energy they integral the vibrational +overlap and any integral involving any + + align:start position:0% +overlap and any integral involving any + + + align:start position:0% +overlap and any integral involving any +power of R will accumulate in a narrow + + align:start position:0% +power of R will accumulate in a narrow + + + align:start position:0% +power of R will accumulate in a narrow +region + + align:start position:0% +region + + + align:start position:0% +region +at the internuclear distance where the + + align:start position:0% +at the internuclear distance where the + + + align:start position:0% +at the internuclear distance where the +two curves + + align:start position:0% + + + + align:start position:0% + +cross and so for all vibrational Matrix + + align:start position:0% +cross and so for all vibrational Matrix + + + align:start position:0% +cross and so for all vibrational Matrix +elements there is hiding in here this + + align:start position:0% +elements there is hiding in here this + + + align:start position:0% +elements there is hiding in here this +stationary phase + + align:start position:0% +stationary phase + + + align:start position:0% +stationary phase +situation this just means that when the + + align:start position:0% +situation this just means that when the + + + align:start position:0% +situation this just means that when the +two wave functions have the + + align:start position:0% +two wave functions have the + + + align:start position:0% +two wave functions have the +same nuclear kinetic + + align:start position:0% +same nuclear kinetic + + + align:start position:0% +same nuclear kinetic +energy they're oscillating at the same + + align:start position:0% +energy they're oscillating at the same + + + align:start position:0% +energy they're oscillating at the same +spatial + + align:start position:0% +spatial + + + align:start position:0% +spatial +frequency they have the same + + align:start position:0% + + + + align:start position:0% + +momentum and the momentum gives you the + + align:start position:0% +momentum and the momentum gives you the + + + align:start position:0% +momentum and the momentum gives you the +de Bry + + align:start position:0% +de Bry + + + align:start position:0% +de Bry +wavelength to the BR wavelength Lambda + + align:start position:0% +wavelength to the BR wavelength Lambda + + + align:start position:0% +wavelength to the BR wavelength Lambda +is uh H over + + align:start position:0% +is uh H over + + + align:start position:0% +is uh H over +e and so if they have the same kinetic + + align:start position:0% +e and so if they have the same kinetic + + + align:start position:0% +e and so if they have the same kinetic +energy they have the same + + align:start position:0% +energy they have the same + + + align:start position:0% +energy they have the same +momentum they have the same wavelength + + align:start position:0% +momentum they have the same wavelength + + + align:start position:0% +momentum they have the same wavelength +that means that at this point they're + + align:start position:0% +that means that at this point they're + + + align:start position:0% +that means that at this point they're +oscillating at the same + + align:start position:0% +oscillating at the same + + + align:start position:0% +oscillating at the same +frequency and so the + + align:start position:0% +frequency and so the + + + align:start position:0% +frequency and so the +integrant uh which uh is the product of + + align:start position:0% +integrant uh which uh is the product of + + + align:start position:0% +integrant uh which uh is the product of +two wave functions that integrant + + align:start position:0% +two wave functions that integrant + + + align:start position:0% +two wave functions that integrant +oscillates very fast except near this + + align:start position:0% +oscillates very fast except near this + + + align:start position:0% +oscillates very fast except near this +point and that's why the r centr + + align:start position:0% +point and that's why the r centr + + + align:start position:0% +point and that's why the r centr +approximation + + align:start position:0% +approximation + + + align:start position:0% +approximation +works and we'll return to this when we + + align:start position:0% +works and we'll return to this when we + + + align:start position:0% +works and we'll return to this when we +talk about the semic classical approach + + align:start position:0% +talk about the semic classical approach + + + align:start position:0% +talk about the semic classical approach +to uh everything + + align:start position:0% +to uh everything + + + align:start position:0% +to uh everything +okay but the rcent approximation is very + + align:start position:0% +okay but the rcent approximation is very + + + align:start position:0% +okay but the rcent approximation is very +convenient because in order to deal + + align:start position:0% +convenient because in order to deal + + + align:start position:0% +convenient because in order to deal +with + + align:start position:0% +with + + + align:start position:0% +with +um these kinds of Matrix elements one + + align:start position:0% +um these kinds of Matrix elements one + + + align:start position:0% +um these kinds of Matrix elements one +has to calculate only two integrals this + + align:start position:0% +has to calculate only two integrals this + + + align:start position:0% +has to calculate only two integrals this +one and the integral involving R the r + + align:start position:0% +one and the integral involving R the r + + + align:start position:0% +one and the integral involving R the r +centroid is this over + + align:start position:0% +centroid is this over + + + align:start position:0% +centroid is this over +that uh is the uh yes so there's only + + align:start position:0% +that uh is the uh yes so there's only + + + align:start position:0% +that uh is the uh yes so there's only +for every pair of VI and VJ instead of + + align:start position:0% +for every pair of VI and VJ instead of + + + align:start position:0% +for every pair of VI and VJ instead of +having to calculate Matrix elements of + + align:start position:0% +having to calculate Matrix elements of + + + align:start position:0% +having to calculate Matrix elements of +all powers of R when just calculates the + + align:start position:0% +all powers of R when just calculates the + + + align:start position:0% +all powers of R when just calculates the +overlap and the Matrix element of R to + + align:start position:0% +overlap and the Matrix element of R to + + + align:start position:0% +overlap and the Matrix element of R to +the one + + align:start position:0% +the one + + + align:start position:0% +the one +power and that leads to tremendous + + align:start position:0% +power and that leads to tremendous + + + align:start position:0% +power and that leads to tremendous +simplification of effort and it also + + align:start position:0% +simplification of effort and it also + + + align:start position:0% +simplification of effort and it also +allows us to describe things in a way + + align:start position:0% +allows us to describe things in a way + + + align:start position:0% +allows us to describe things in a way +that's much + + align:start position:0% + + + + align:start position:0% + +simpler + + align:start position:0% +simpler + + + align:start position:0% +simpler +the observables s + + align:start position:0% +the observables s + + + align:start position:0% +the observables s +the AR + + align:start position:0% +the AR + + + align:start position:0% +the AR +dependence of electronic quantities only + + align:start position:0% +dependence of electronic quantities only + + + align:start position:0% +dependence of electronic quantities only +in the + + align:start position:0% +in the + + + align:start position:0% +in the +vicinity of some special point which you + + align:start position:0% +vicinity of some special point which you + + + align:start position:0% +vicinity of some special point which you +know and so they're not terribly + + align:start position:0% +know and so they're not terribly + + + align:start position:0% +know and so they're not terribly +sensitive to curvature to strange + + align:start position:0% +sensitive to curvature to strange + + + align:start position:0% +sensitive to curvature to strange +variations and so one can ignore the r + + align:start position:0% +variations and so one can ignore the r + + + align:start position:0% +variations and so one can ignore the r +dependence of electronic + + align:start position:0% +dependence of electronic + + + align:start position:0% +dependence of electronic +quantities for most + + align:start position:0% +quantities for most + + + align:start position:0% +quantities for most +calculations this is very + + align:start position:0% +calculations this is very + + + align:start position:0% +calculations this is very +helpful and it would not be + + align:start position:0% +helpful and it would not be + + + align:start position:0% +helpful and it would not be +clear if you were simply doing numerical + + align:start position:0% +clear if you were simply doing numerical + + + align:start position:0% +clear if you were simply doing numerical +calculations because you would always do + + align:start position:0% +calculations because you would always do + + + align:start position:0% +calculations because you would always do +the numerical calculation correctly and + + align:start position:0% +the numerical calculation correctly and + + + align:start position:0% +the numerical calculation correctly and +you'd be doing you know you turn the + + align:start position:0% +you'd be doing you know you turn the + + + align:start position:0% +you'd be doing you know you turn the +crank and youd get something but you + + align:start position:0% +crank and youd get something but you + + + align:start position:0% +crank and youd get something but you +wouldn't know + + align:start position:0% +wouldn't know + + + align:start position:0% +wouldn't know +that everything interesting is happening + + align:start position:0% +that everything interesting is happening + + + align:start position:0% +that everything interesting is happening +in a particular + + align:start position:0% + + + + align:start position:0% + +place and the nature of your wave + + align:start position:0% +place and the nature of your wave + + + align:start position:0% +place and the nature of your wave +function at that internuclear distance + + align:start position:0% +function at that internuclear distance + + + align:start position:0% +function at that internuclear distance +is what determines what happens in the + + align:start position:0% +is what determines what happens in the + + + align:start position:0% +is what determines what happens in the +experiment and a different experiment + + align:start position:0% +experiment and a different experiment + + + align:start position:0% +experiment and a different experiment +might have curve cross at a different R + + align:start position:0% +might have curve cross at a different R + + + align:start position:0% +might have curve cross at a different R +and it might sample the away from a + + align:start position:0% +and it might sample the away from a + + + align:start position:0% +and it might sample the away from a +different place and give you something + + align:start position:0% +different place and give you something + + + align:start position:0% +different place and give you something +else + + align:start position:0% +else + + + align:start position:0% +else +okay yes so where would this would break + + align:start position:0% +okay yes so where would this would break + + + align:start position:0% +okay yes so where would this would break +down if you had say uh two peaks if your + + align:start position:0% +down if you had say uh two peaks if your + + + align:start position:0% +down if you had say uh two peaks if your +wave function had two maximum and they + + align:start position:0% +wave function had two maximum and they + + + align:start position:0% +wave function had two maximum and they +would that be a case of where it breaks + + align:start position:0% +would that be a case of where it breaks + + + align:start position:0% +would that be a case of where it breaks +down no it'll break down when you have + + align:start position:0% +down no it'll break down when you have + + + align:start position:0% +down no it'll break down when you have +something like this where there's no + + align:start position:0% +something like this where there's no + + + align:start position:0% +something like this where there's no +spatial + + align:start position:0% +spatial + + + align:start position:0% +spatial +overlap between the two vibrational WS + + align:start position:0% +overlap between the two vibrational WS + + + align:start position:0% +overlap between the two vibrational WS +an R will be in the middle it we'll try + + align:start position:0% +an R will be in the middle it we'll try + + + align:start position:0% +an R will be in the middle it we'll try +to be somewhere here and the the so it's + + align:start position:0% +to be somewhere here and the the so it's + + + align:start position:0% +to be somewhere here and the the so it's +in the Tails of the wave functions and + + align:start position:0% +in the Tails of the wave functions and + + + align:start position:0% +in the Tails of the wave functions and +so there's just no get a weird value for + + align:start position:0% +so there's just no get a weird value for + + + align:start position:0% +so there's just no get a weird value for +the + + align:start position:0% +the + + + align:start position:0% +the +elect that's going to be really high + + align:start position:0% +elect that's going to be really high + + + align:start position:0% +elect that's going to be really high +because it's really high on those curves + + align:start position:0% +because it's really high on those curves + + + align:start position:0% +because it's really high on those curves +and the wave functions aren't even there + + align:start position:0% +and the wave functions aren't even there + + + align:start position:0% +and the wave functions aren't even there +that's right so when you have when + + align:start position:0% +that's right so when you have when + + + align:start position:0% +that's right so when you have when +you're dividing by zero you don't expect + + align:start position:0% +you're dividing by zero you don't expect + + + align:start position:0% +you're dividing by zero you don't expect +to have very much of a purchase on + + align:start position:0% +to have very much of a purchase on + + + align:start position:0% +to have very much of a purchase on +whatever it is you're King so then the + + align:start position:0% +whatever it is you're King so then the + + + align:start position:0% +whatever it is you're King so then the +overlap integral is really small for a + + align:start position:0% +overlap integral is really small for a + + + align:start position:0% +overlap integral is really small for a +good reason right as opposed to because + + align:start position:0% +good reason right as opposed to because + + + align:start position:0% +good reason right as opposed to because +of an accidental + + align:start position:0% +of an accidental + + + align:start position:0% +of an accidental +cancellation then the r centroid + + align:start position:0% +cancellation then the r centroid + + + align:start position:0% +cancellation then the r centroid +approximation really fails I was just + + align:start position:0% +approximation really fails I was just + + + align:start position:0% +approximation really fails I was just +wondering if you had if the wave + + align:start position:0% +wondering if you had if the wave + + + align:start position:0% +wondering if you had if the wave +functions happen to have two Maxima and + + align:start position:0% +functions happen to have two Maxima and + + + align:start position:0% +functions happen to have two Maxima and +those happen to be if if they had two + + align:start position:0% +those happen to be if if they had two + + + align:start position:0% +those happen to be if if they had two +maximum basically essentially what + + align:start position:0% +maximum basically essentially what + + + align:start position:0% +maximum basically essentially what +you're calculating is the average value + + align:start position:0% +you're calculating is the average value + + + align:start position:0% +you're calculating is the average value +of r + + align:start position:0% +of r + + + align:start position:0% +of r +with the the that first with the r + + align:start position:0% +with the the that first with the r + + + align:start position:0% +with the the that first with the r +centroid right and so if you had two + + align:start position:0% +centroid right and so if you had two + + + align:start position:0% +centroid right and so if you had two +Maxima of the wave function the average + + align:start position:0% +Maxima of the wave function the average + + + align:start position:0% +Maxima of the wave function the average +value of R might turn out to be in + + align:start position:0% +value of R might turn out to be in + + + align:start position:0% +value of R might turn out to be in +between them that's okay because the + + align:start position:0% +between them that's okay because the + + + align:start position:0% +between them that's okay because the +wave function isn't zero except at + + align:start position:0% +wave function isn't zero except at + + + align:start position:0% +wave function isn't zero except at +nodes right and so uh what you're + + align:start position:0% +nodes right and so uh what you're + + + align:start position:0% +nodes right and so uh what you're +basically doing is you're measuring at + + align:start position:0% +basically doing is you're measuring at + + + align:start position:0% +basically doing is you're measuring at +this special Point what is the classical + + align:start position:0% +this special Point what is the classical + + + align:start position:0% +this special Point what is the classical +probability which is related to the + + align:start position:0% +probability which is related to the + + + align:start position:0% +probability which is related to the +classical velocity + + align:start position:0% +classical velocity + + + align:start position:0% +classical velocity +or one over the classical velocity which + + align:start position:0% +or one over the classical velocity which + + + align:start position:0% +or one over the classical velocity which +is related to the classical moment + + align:start position:0% +is related to the classical moment + + + align:start position:0% +is related to the classical moment +momentum so you can uh you can still + + align:start position:0% +momentum so you can uh you can still + + + align:start position:0% +momentum so you can uh you can still +have small vibrational + + align:start position:0% +have small vibrational + + + align:start position:0% +have small vibrational +overlaps and still have the AR centroid + + align:start position:0% +overlaps and still have the AR centroid + + + align:start position:0% +overlaps and still have the AR centroid +approximation work because it's + + align:start position:0% +approximation work because it's + + + align:start position:0% +approximation work because it's +basically telling you that it's at this + + align:start position:0% +basically telling you that it's at this + + + align:start position:0% +basically telling you that it's at this +place and the the two uh the two + + align:start position:0% +place and the the two uh the two + + + align:start position:0% +place and the the two uh the two +vibrational levels correspond to the + + align:start position:0% +vibrational levels correspond to the + + + align:start position:0% +vibrational levels correspond to the +particle moving really fast in that + + align:start position:0% +particle moving really fast in that + + + align:start position:0% +particle moving really fast in that +region but there's it's still classical + + align:start position:0% +region but there's it's still classical + + + align:start position:0% +region but there's it's still classical +you still get the results by using + + align:start position:0% +you still get the results by using + + + align:start position:0% +you still get the results by using +classical mechanics in account in + + align:start position:0% +classical mechanics in account in + + + align:start position:0% +classical mechanics in account in +a semiquantum mechanical + + align:start position:0% +a semiquantum mechanical + + + align:start position:0% +a semiquantum mechanical +way it's almost always true that you can + + align:start position:0% +way it's almost always true that you can + + + align:start position:0% +way it's almost always true that you can +use classical + + align:start position:0% +use classical + + + align:start position:0% +use classical +mechanics embedded in a quantum + + align:start position:0% +mechanics embedded in a quantum + + + align:start position:0% +mechanics embedded in a quantum +mechanical + + align:start position:0% +mechanical + + + align:start position:0% +mechanical +framework and get the + + align:start position:0% +framework and get the + + + align:start position:0% +framework and get the +answer and when you do that you get what + + align:start position:0% +answer and when you do that you get what + + + align:start position:0% +answer and when you do that you get what +you're told you're not supposed to be + + align:start position:0% +you're told you're not supposed to be + + + align:start position:0% +you're told you're not supposed to be +able to get from quantum + + align:start position:0% +able to get from quantum + + + align:start position:0% +able to get from quantum +which + + align:start position:0% +which + + + align:start position:0% +which +is uh where does something + + align:start position:0% +is uh where does something + + + align:start position:0% +is uh where does something +happen in quantum mechanics it says this + + align:start position:0% +happen in quantum mechanics it says this + + + align:start position:0% +happen in quantum mechanics it says this +is the probability of something + + align:start position:0% +is the probability of something + + + align:start position:0% +is the probability of something +happening but in classical mechanics + + align:start position:0% +happening but in classical mechanics + + + align:start position:0% +happening but in classical mechanics +you're watching X and P as a function of + + align:start position:0% +you're watching X and P as a function of + + + align:start position:0% +you're watching X and P as a function of +time and you can say something happened + + align:start position:0% +time and you can say something happened + + + align:start position:0% +time and you can say something happened +at this position and at this time and + + align:start position:0% +at this position and at this time and + + + align:start position:0% +at this position and at this time and +the particle was going this + + align:start position:0% + + + + align:start position:0% + +fast and so you know what the forces + + align:start position:0% +fast and so you know what the forces + + + align:start position:0% +fast and so you know what the forces +were and you know you know so everything + + align:start position:0% +were and you know you know so everything + + + align:start position:0% +were and you know you know so everything +starts to have interpretation when you + + align:start position:0% +starts to have interpretation when you + + + align:start position:0% +starts to have interpretation when you +can embed classical mechanics in quantum + + align:start position:0% +can embed classical mechanics in quantum + + + align:start position:0% +can embed classical mechanics in quantum +mechanics so quantum mechanics says + + align:start position:0% +mechanics so quantum mechanics says + + + align:start position:0% +mechanics so quantum mechanics says +you're not supposed to know this stuff + + align:start position:0% +you're not supposed to know this stuff + + + align:start position:0% +you're not supposed to know this stuff +but usually you + + align:start position:0% + + + + align:start position:0% + +can and whenever you have an + + align:start position:0% +can and whenever you have an + + + align:start position:0% +can and whenever you have an +approximation like this saying you know + + align:start position:0% +approximation like this saying you know + + + align:start position:0% +approximation like this saying you know +everything accumulates I mean the only + + align:start position:0% +everything accumulates I mean the only + + + align:start position:0% +everything accumulates I mean the only +way you can have the r centroid + + align:start position:0% +way you can have the r centroid + + + align:start position:0% +way you can have the r centroid +approximation work is if things + + align:start position:0% +approximation work is if things + + + align:start position:0% +approximation work is if things +accumulated at a specific r + + align:start position:0% +accumulated at a specific r + + + align:start position:0% +accumulated at a specific r +I think this is what I mean Dave's + + align:start position:0% +I think this is what I mean Dave's + + + align:start position:0% +I think this is what I mean Dave's +question kind of recap is if you have + + align:start position:0% +question kind of recap is if you have + + + align:start position:0% +question kind of recap is if you have +two different potentials yes and they + + align:start position:0% +two different potentials yes and they + + + align:start position:0% +two different potentials yes and they +both have all their you know you're high + + align:start position:0% +both have all their you know you're high + + + align:start position:0% +both have all their you know you're high +vibrational State all the probability of + + align:start position:0% +vibrational State all the probability of + + + align:start position:0% +vibrational State all the probability of +two sides of both yes you're calculating + + align:start position:0% +two sides of both yes you're calculating + + + align:start position:0% +two sides of both yes you're calculating +an over electronic integral between + + align:start position:0% +an over electronic integral between + + + align:start position:0% +an over electronic integral between +those two yes you're going to say the + + align:start position:0% +those two yes you're going to say the + + + align:start position:0% +those two yes you're going to say the +are centroids in the middle and there's + + align:start position:0% +are centroids in the middle and there's + + + align:start position:0% +are centroids in the middle and there's +nothing there because all the action + + align:start position:0% +nothing there because all the action + + + align:start position:0% +nothing there because all the action +happens at the sides of both but + + align:start position:0% +happens at the sides of both but + + + align:start position:0% +happens at the sides of both but +classically uh you know how much you you + + align:start position:0% +classically uh you know how much you you + + + align:start position:0% +classically uh you know how much you you +know what I mean there is nothing there + + align:start position:0% +know what I mean there is nothing there + + + align:start position:0% +know what I mean there is nothing there +there's a little bit + + align:start position:0% +there's a little bit + + + align:start position:0% +there's a little bit +there and you know exactly how to + + align:start position:0% +there and you know exactly how to + + + align:start position:0% +there and you know exactly how to +calculate that because in the middle + + align:start position:0% +calculate that because in the middle + + + align:start position:0% +calculate that because in the middle +region where things are going really + + align:start position:0% +region where things are going really + + + align:start position:0% +region where things are going really +fast it's a lot of + + align:start position:0% +fast it's a lot of + + + align:start position:0% +fast it's a lot of +oscillations and uh so there's not going + + align:start position:0% +oscillations and uh so there's not going + + + align:start position:0% +oscillations and uh so there's not going +to be but then you're saying that the + + align:start position:0% +to be but then you're saying that the + + + align:start position:0% +to be but then you're saying that the +electronic whatever electronic integral + + align:start position:0% +electronic whatever electronic integral + + + align:start position:0% +electronic whatever electronic integral +you're calculating is determined by that + + align:start position:0% +you're calculating is determined by that + + + align:start position:0% +you're calculating is determined by that +point when you think would be determined + + align:start position:0% +point when you think would be determined + + + align:start position:0% +point when you think would be determined +where by where all the vibrational + + align:start position:0% +where by where all the vibrational + + + align:start position:0% +where by where all the vibrational +amplitude is the turning points but you + + align:start position:0% +amplitude is the turning points but you + + + align:start position:0% +amplitude is the turning points but you +would be + + align:start position:0% +would be + + + align:start position:0% +would be +it's determined where the stationary + + align:start position:0% +it's determined where the stationary + + + align:start position:0% +it's determined where the stationary +phase is and it's determined by how much + + align:start position:0% +phase is and it's determined by how much + + + align:start position:0% +phase is and it's determined by how much +time the particle spends in the + + align:start position:0% +time the particle spends in the + + + align:start position:0% +time the particle spends in the +stationary phase region what does that + + align:start position:0% +stationary phase region what does that + + + align:start position:0% +stationary phase region what does that +mean well we know a + + align:start position:0% +mean well we know a + + + align:start position:0% +mean well we know a +velocity and we ask well what is the + + align:start position:0% +velocity and we ask well what is the + + + align:start position:0% +velocity and we ask well what is the +stationary phase how far can it go + + align:start position:0% +stationary phase how far can it go + + + align:start position:0% +stationary phase how far can it go +before the two wave functions get pile + + align:start position:0% +before the two wave functions get pile + + + align:start position:0% +before the two wave functions get pile +out of phase or accumulate a pi phase + + align:start position:0% +out of phase or accumulate a pi phase + + + align:start position:0% +out of phase or accumulate a pi phase +error so the + + align:start position:0% +error so the + + + align:start position:0% +error so the +integrand the integral will accumulate + + align:start position:0% +integrand the integral will accumulate + + + align:start position:0% +integrand the integral will accumulate +about the stationary face Point overall + + align:start position:0% +about the stationary face Point overall + + + align:start position:0% +about the stationary face Point overall +length which is determined by how far + + align:start position:0% +length which is determined by how far + + + align:start position:0% +length which is determined by how far +you can go before the two-way function + + align:start position:0% +you can go before the two-way function + + + align:start position:0% +you can go before the two-way function +Pi phase + + align:start position:0% +Pi phase + + + align:start position:0% +Pi phase +difference and that's related to the + + align:start position:0% +difference and that's related to the + + + align:start position:0% +difference and that's related to the +difference in slopes of the + + align:start position:0% +difference in slopes of the + + + align:start position:0% +difference in slopes of the +potentials and the the value that + + align:start position:0% +potentials and the the value that + + + align:start position:0% +potentials and the the value that +accumulates is the classical + + align:start position:0% +accumulates is the classical + + + align:start position:0% +accumulates is the classical +envelope which is one over the velocity + + align:start position:0% +envelope which is one over the velocity + + + align:start position:0% +envelope which is one over the velocity +and so you can basically evaluate this + + align:start position:0% +and so you can basically evaluate this + + + align:start position:0% +and so you can basically evaluate this +integral not by numerical integration + + align:start position:0% +integral not by numerical integration + + + align:start position:0% +integral not by numerical integration +but by classical + + align:start position:0% +but by classical + + + align:start position:0% +but by classical +mechanics you need to know the period of + + align:start position:0% +mechanics you need to know the period of + + + align:start position:0% +mechanics you need to know the period of +oscillation the + + align:start position:0% +oscillation the + + + align:start position:0% +oscillation the +velocity and the stationary phase point + + align:start position:0% +velocity and the stationary phase point + + + align:start position:0% +velocity and the stationary phase point +and how long is the stationary phase + + align:start position:0% +and how long is the stationary phase + + + align:start position:0% +and how long is the stationary phase +region and all of those you can get + + align:start position:0% +region and all of those you can get + + + align:start position:0% +region and all of those you can get +simply by looking at the uh um potential + + align:start position:0% +simply by looking at the uh um potential + + + align:start position:0% +simply by looking at the uh um potential +burs and the fact that the wave + + align:start position:0% +burs and the fact that the wave + + + align:start position:0% +burs and the fact that the wave +functions have big loes that don't + + align:start position:0% +functions have big loes that don't + + + align:start position:0% +functions have big loes that don't +overlap with each other it means that + + align:start position:0% +overlap with each other it means that + + + align:start position:0% +overlap with each other it means that +the the integral is going to be small + + align:start position:0% +the the integral is going to be small + + + align:start position:0% +the the integral is going to be small +but the value of that integral you can + + align:start position:0% + + + + align:start position:0% + +calculate and you can use very simple + + align:start position:0% +calculate and you can use very simple + + + align:start position:0% +calculate and you can use very simple +ideas to get these integrals to factor + + align:start position:0% +ideas to get these integrals to factor + + + align:start position:0% +ideas to get these integrals to factor +to accuracy or you can use a functions + + align:start position:0% +to accuracy or you can use a functions + + + align:start position:0% +to accuracy or you can use a functions +to get the integrals to whatever + + align:start position:0% +to get the integrals to whatever + + + align:start position:0% +to get the integrals to whatever +accuracy you want and to have all of the + + align:start position:0% +accuracy you want and to have all of the + + + align:start position:0% +accuracy you want and to have all of the +you know the dependence on energy and + + align:start position:0% +you know the dependence on energy and + + + align:start position:0% +you know the dependence on energy and +other + + align:start position:0% +other + + + align:start position:0% +other +stuff are you I still + + align:start position:0% +stuff are you I still + + + align:start position:0% +stuff are you I still +what if what if you have two stationary + + align:start position:0% +what if what if you have two stationary + + + align:start position:0% +what if what if you have two stationary +phases if you have two if you have two + + align:start position:0% +phases if you have two if you have two + + + align:start position:0% +phases if you have two if you have two +stationary pH points you're screw I'm + + align:start position:0% +stationary pH points you're screw I'm + + + align:start position:0% +stationary pH points you're screw I'm +not yeah I'm not saying that you have + + align:start position:0% +not yeah I'm not saying that you have + + + align:start position:0% +not yeah I'm not saying that you have +each weight function separately has a + + align:start position:0% + + + + align:start position:0% + +lob two stationary well then and then + + align:start position:0% +lob two stationary well then and then + + + align:start position:0% +lob two stationary well then and then +you end up with an average in the middle + + align:start position:0% +you end up with an average in the middle + + + align:start position:0% +you end up with an average in the middle +that's that's right that's exactly + + align:start position:0% +that's that's right that's exactly + + + align:start position:0% +that's that's right that's exactly +that's if you have two stationary face + + align:start position:0% +that's if you have two stationary face + + + align:start position:0% +that's if you have two stationary face +points + + align:start position:0% +points + + + align:start position:0% +points +then semi classical arguments will not + + align:start position:0% +then semi classical arguments will not + + + align:start position:0% +then semi classical arguments will not +help you because each one is going to + + align:start position:0% +help you because each one is going to + + + align:start position:0% +help you because each one is going to +generate a large + + align:start position:0% +generate a large + + + align:start position:0% +generate a large +contribution to the integral right and + + align:start position:0% +contribution to the integral right and + + + align:start position:0% +contribution to the integral right and +you don't know their relative phas and + + align:start position:0% +you don't know their relative phas and + + + align:start position:0% +you don't know their relative phas and +you end up I mean it seems like our + + align:start position:0% +you end up I mean it seems like our + + + align:start position:0% +you end up I mean it seems like our +average is in the middle even occurring + + align:start position:0% +average is in the middle even occurring + + + align:start position:0% +average is in the middle even occurring +both at the Ed when there are two + + align:start position:0% +both at the Ed when there are two + + + align:start position:0% +both at the Ed when there are two +stationary phase points if you calculate + + align:start position:0% +stationary phase points if you calculate + + + align:start position:0% +stationary phase points if you calculate +the r centroid for uh several different + + align:start position:0% +the r centroid for uh several different + + + align:start position:0% +the r centroid for uh several different +uh uh successive vibration it'll jump + + align:start position:0% +uh uh successive vibration it'll jump + + + align:start position:0% +uh uh successive vibration it'll jump +all over the place okay so there will be + + align:start position:0% +all over the place okay so there will be + + + align:start position:0% +all over the place okay so there will be +warnings okay so that's your warning is + + align:start position:0% +warnings okay so that's your warning is + + + align:start position:0% +warnings okay so that's your warning is +that + + align:start position:0% +that + + + align:start position:0% +that +you're so and you can tell you you have + + align:start position:0% +you're so and you can tell you you have + + + align:start position:0% +you're so and you can tell you you have +two potential + + align:start position:0% +two potential + + + align:start position:0% +two potential +curves um and you subtract the + + align:start position:0% +curves um and you subtract the + + + align:start position:0% +curves um and you subtract the +two and you look at the difference + + align:start position:0% +two and you look at the difference + + + align:start position:0% +two and you look at the difference +potential as a function R the stationary + + align:start position:0% +potential as a function R the stationary + + + align:start position:0% +potential as a function R the stationary +face point is where the difference + + align:start position:0% +face point is where the difference + + + align:start position:0% +face point is where the difference +potential has zero + + align:start position:0% +potential has zero + + + align:start position:0% +potential has zero +derivative and if there's two or three + + align:start position:0% +derivative and if there's two or three + + + align:start position:0% +derivative and if there's two or three +places where it has zero derivative + + align:start position:0% +places where it has zero derivative + + + align:start position:0% +places where it has zero derivative +you're + + align:start position:0% + + + + align:start position:0% + +warned and sometimes you can get away + + align:start position:0% +warned and sometimes you can get away + + + align:start position:0% +warned and sometimes you can get away +with it because there's only large + + align:start position:0% +with it because there's only large + + + align:start position:0% +with it because there's only large +amplitude at one of those uh if there's + + align:start position:0% +amplitude at one of those uh if there's + + + align:start position:0% +amplitude at one of those uh if there's +large amplitude at Several of them or + + align:start position:0% +large amplitude at Several of them or + + + align:start position:0% +large amplitude at Several of them or +small amplitude at all of them then + + align:start position:0% +small amplitude at all of them then + + + align:start position:0% +small amplitude at all of them then +you're going to have to worry about the + + align:start position:0% +you're going to have to worry about the + + + align:start position:0% +you're going to have to worry about the +relative phases and that's where quantum + + align:start position:0% +relative phases and that's where quantum + + + align:start position:0% +relative phases and that's where quantum +mechanics does stuff that classical + + align:start position:0% +mechanics does stuff that classical + + + align:start position:0% +mechanics does stuff that classical +mechanics can't + + align:start position:0% +mechanics can't + + + align:start position:0% +mechanics can't +touch I mean there isn't interference in + + align:start position:0% +touch I mean there isn't interference in + + + align:start position:0% +touch I mean there isn't interference in +classical + + align:start position:0% +classical + + + align:start position:0% +classical +mechanics you can still use classical + + align:start position:0% +mechanics you can still use classical + + + align:start position:0% +mechanics you can still use classical +mechanics to guide you to the one thing + + align:start position:0% +mechanics to guide you to the one thing + + + align:start position:0% +mechanics to guide you to the one thing +you have to get from the + + align:start position:0% +you have to get from the + + + align:start position:0% +you have to get from the +clchs but often there's no point once + + align:start position:0% +clchs but often there's no point once + + + align:start position:0% +clchs but often there's no point once +you go that part you might as well use + + align:start position:0% +you go that part you might as well use + + + align:start position:0% +you go that part you might as well use +the + + align:start position:0% + + + + align:start position:0% + +qu okay uh we still have a few + + align:start position:0% +qu okay uh we still have a few + + + align:start position:0% +qu okay uh we still have a few +minutes okay now we're on page five of + + align:start position:0% +minutes okay now we're on page five of + + + align:start position:0% +minutes okay now we're on page five of +my + + align:start position:0% + + + + align:start position:0% + +notes + + align:start position:0% +notes + + + align:start position:0% +notes +so the born up and armor approximation + + align:start position:0% +so the born up and armor approximation + + + align:start position:0% +so the born up and armor approximation +tells us how to + + align:start position:0% +tells us how to + + + align:start position:0% +tells us how to +begin and uh usually life is a lot + + align:start position:0% +begin and uh usually life is a lot + + + align:start position:0% +begin and uh usually life is a lot +simpler than you have any reason to + + align:start position:0% +simpler than you have any reason to + + + align:start position:0% +simpler than you have any reason to +expect that the Spectra are really + + align:start position:0% +expect that the Spectra are really + + + align:start position:0% +expect that the Spectra are really +regular that there are nice simple + + align:start position:0% +regular that there are nice simple + + + align:start position:0% +regular that there are nice simple +patterns and uh uh that there is no hint + + align:start position:0% +patterns and uh uh that there is no hint + + + align:start position:0% +patterns and uh uh that there is no hint +that bad things are happening or could + + align:start position:0% +that bad things are happening or could + + + align:start position:0% +that bad things are happening or could +happen and so there's two limits one is + + align:start position:0% +happen and so there's two limits one is + + + align:start position:0% +happen and so there's two limits one is +the limit where H I J the op diagonal + + align:start position:0% +the limit where H I J the op diagonal + + + align:start position:0% +the limit where H I J the op diagonal +matrix element between two states that + + align:start position:0% +matrix element between two states that + + + align:start position:0% +matrix element between two states that +might be near each other two zero order + + align:start position:0% +might be near each other two zero order + + + align:start position:0% +might be near each other two zero order +born alimer + + align:start position:0% + + + + align:start position:0% + +States or case a diabetic States or + + align:start position:0% + + + + align:start position:0% + +whatever so the Matrix + + align:start position:0% + + + + align:start position:0% + +element over the energy difference is + + align:start position:0% +element over the energy difference is + + + align:start position:0% +element over the energy difference is +small so this is the situation that + + align:start position:0% +small so this is the situation that + + + align:start position:0% +small so this is the situation that +leads to unexpected Simplicity + + align:start position:0% +leads to unexpected Simplicity + + + align:start position:0% +leads to unexpected Simplicity +undeserved + + align:start position:0% +undeserved + + + align:start position:0% +undeserved +Simplicity there are all sorts of off + + align:start position:0% +Simplicity there are all sorts of off + + + align:start position:0% +Simplicity there are all sorts of off +diagonal matrix + + align:start position:0% +diagonal matrix + + + align:start position:0% +diagonal matrix +lurking but none of them lead to + + align:start position:0% +lurking but none of them lead to + + + align:start position:0% +lurking but none of them lead to +observable + + align:start position:0% +observable + + + align:start position:0% +observable +effects or very important effects when + + align:start position:0% +effects or very important effects when + + + align:start position:0% +effects or very important effects when +this is true one can always correct uh + + align:start position:0% +this is true one can always correct uh + + + align:start position:0% +this is true one can always correct uh +the energies by + + align:start position:0% + + + + align:start position:0% + +idation so this is Delta + + align:start position:0% + + + + align:start position:0% + +e um so the energies are corrected by + + align:start position:0% +e um so the energies are corrected by + + + align:start position:0% +e um so the energies are corrected by +this this is small it usually varies + + align:start position:0% +this this is small it usually varies + + + align:start position:0% +this this is small it usually varies +with uh State smoothly and so you don't + + align:start position:0% +with uh State smoothly and so you don't + + + align:start position:0% +with uh State smoothly and so you don't +really see anything + + align:start position:0% +really see anything + + + align:start position:0% +really see anything +weird but then there's the other limit + + align:start position:0% +weird but then there's the other limit + + + align:start position:0% +weird but then there's the other limit +where this quantity is much much larger + + align:start position:0% +where this quantity is much much larger + + + align:start position:0% +where this quantity is much much larger +than one and that's usually because of + + align:start position:0% +than one and that's usually because of + + + align:start position:0% +than one and that's usually because of +an accidental + + align:start position:0% +an accidental + + + align:start position:0% +an accidental +degeneracy so there's nothing really in + + align:start position:0% +degeneracy so there's nothing really in + + + align:start position:0% +degeneracy so there's nothing really in +the hamiltonian that says this is going + + align:start position:0% +the hamiltonian that says this is going + + + align:start position:0% +the hamiltonian that says this is going +to happen it's just the levels which + + align:start position:0% +to happen it's just the levels which + + + align:start position:0% +to happen it's just the levels which +you've normally been ignoring + + align:start position:0% +you've normally been ignoring + + + align:start position:0% +you've normally been ignoring +interactions between accidentally fall + + align:start position:0% +interactions between accidentally fall + + + align:start position:0% +interactions between accidentally fall +near each + + align:start position:0% +near each + + + align:start position:0% +near each +other and whenever that happens you + + align:start position:0% +other and whenever that happens you + + + align:start position:0% +other and whenever that happens you +can't use Ordinary second order + + align:start position:0% +can't use Ordinary second order + + + align:start position:0% +can't use Ordinary second order +perturbation Theory you get local + + align:start position:0% +perturbation Theory you get local + + + align:start position:0% +perturbation Theory you get local +effects and these are called + + align:start position:0% + + + + align:start position:0% + +perations the this regular thing is + + align:start position:0% +perations the this regular thing is + + + align:start position:0% +perations the this regular thing is +messed up there is something that looks + + align:start position:0% +messed up there is something that looks + + + align:start position:0% +messed up there is something that looks +wrong except there's nothing wrong about + + align:start position:0% +wrong except there's nothing wrong about + + + align:start position:0% +wrong except there's nothing wrong about +it U and but it requires a special + + align:start position:0% +it U and but it requires a special + + + align:start position:0% +it U and but it requires a special +treatment because of + + align:start position:0% +treatment because of + + + align:start position:0% +treatment because of +this unusual energy denominator that + + align:start position:0% +this unusual energy denominator that + + + align:start position:0% +this unusual energy denominator that +brings these zero order States close + + align:start position:0% +brings these zero order States close + + + align:start position:0% +brings these zero order States close +together and forces you to deal with the + + align:start position:0% +together and forces you to deal with the + + + align:start position:0% +together and forces you to deal with the +true evil of + + align:start position:0% + + + + align:start position:0% + +nature + + align:start position:0% +nature + + + align:start position:0% +nature +okay + + align:start position:0% +okay + + + align:start position:0% +okay +there's there's many types of + + align:start position:0% +there's there's many types of + + + align:start position:0% +there's there's many types of +perturbations one is we have a bound + + align:start position:0% +perturbations one is we have a bound + + + align:start position:0% +perturbations one is we have a bound +potential curve and another bound + + align:start position:0% +potential curve and another bound + + + align:start position:0% +potential curve and another bound +potential curve and we have vibrational + + align:start position:0% +potential curve and we have vibrational + + + align:start position:0% +potential curve and we have vibrational +levels of this and vibrational levels of + + align:start position:0% +levels of this and vibrational levels of + + + align:start position:0% +levels of this and vibrational levels of +this and they're near each other and + + align:start position:0% +this and they're near each other and + + + align:start position:0% +this and they're near each other and +then if we look at the + + align:start position:0% +then if we look at the + + + align:start position:0% +then if we look at the +energy versus J * J + + + align:start position:0% +energy versus J * J + + + + align:start position:0% +energy versus J * J + + + align:start position:0% + + + align:start position:0% +we get something like that remember uh + + align:start position:0% +we get something like that remember uh + + + align:start position:0% +we get something like that remember uh +the energies versus J J + 1 will appear + + align:start position:0% +the energies versus J J + 1 will appear + + + align:start position:0% +the energies versus J J + 1 will appear +as straight lines with slope of B and if + + align:start position:0% +as straight lines with slope of B and if + + + align:start position:0% +as straight lines with slope of B and if +you have different rotational constants + + align:start position:0% +you have different rotational constants + + + align:start position:0% +you have different rotational constants +these curves will + + align:start position:0% +these curves will + + + align:start position:0% +these curves will +cross so at this place where we have + + align:start position:0% +cross so at this place where we have + + + align:start position:0% +cross so at this place where we have +states of the same J that are degenerate + + align:start position:0% +states of the same J that are degenerate + + + align:start position:0% +states of the same J that are degenerate +something bad is going to happen and now + + align:start position:0% +something bad is going to happen and now + + + align:start position:0% +something bad is going to happen and now +suppose Nature has said well I can to + + align:start position:0% +suppose Nature has said well I can to + + + align:start position:0% +suppose Nature has said well I can to +this level because like we have a + + align:start position:0% +this level because like we have a + + + align:start position:0% +this level because like we have a +singlet ground state this is a singlet + + align:start position:0% +singlet ground state this is a singlet + + + align:start position:0% +singlet ground state this is a singlet +state but this is a triplet State I + + align:start position:0% +state but this is a triplet State I + + + align:start position:0% +state but this is a triplet State I +can't exite to that this is called a + + align:start position:0% +can't exite to that this is called a + + + align:start position:0% +can't exite to that this is called a +Bright State this is called a dark + + align:start position:0% +Bright State this is called a dark + + + align:start position:0% +Bright State this is called a dark +State and so uh uh if I um well now + + align:start position:0% +State and so uh uh if I um well now + + + align:start position:0% +State and so uh uh if I um well now +there's some pictures that I handed out + + align:start position:0% +there's some pictures that I handed out + + + align:start position:0% +there's some pictures that I handed out +that uh + + align:start position:0% +that uh + + + align:start position:0% +that uh +um + + align:start position:0% + + + + align:start position:0% + +um + + align:start position:0% +um + + + align:start position:0% +um +this uh what is a peration here is a + + align:start position:0% +this uh what is a peration here is a + + + align:start position:0% +this uh what is a peration here is a +spectrum recorded on a photographic + + align:start position:0% +spectrum recorded on a photographic + + + align:start position:0% +spectrum recorded on a photographic +plate which nobody ever does it but it + + align:start position:0% +plate which nobody ever does it but it + + + align:start position:0% +plate which nobody ever does it but it +it uh makes it so clear you see this + + align:start position:0% +it uh makes it so clear you see this + + + align:start position:0% +it uh makes it so clear you see this +regular spacing of + + align:start position:0% +regular spacing of + + + align:start position:0% +regular spacing of +lines that's an unperturbed Spectrum + + align:start position:0% +lines that's an unperturbed Spectrum + + + align:start position:0% +lines that's an unperturbed Spectrum +that's a textbook Spectrum there's no + + align:start position:0% +that's a textbook Spectrum there's no + + + align:start position:0% +that's a textbook Spectrum there's no +Dynamics in it nothing + + align:start position:0% +Dynamics in it nothing + + + align:start position:0% +Dynamics in it nothing +interesting and that's what most people + + align:start position:0% +interesting and that's what most people + + + align:start position:0% +interesting and that's what most people +would like to see because they're risk + + align:start position:0% +would like to see because they're risk + + + align:start position:0% +would like to see because they're risk +ofers and then this is just the next + + align:start position:0% +ofers and then this is just the next + + + align:start position:0% +ofers and then this is just the next +vibrational level higher in that same + + align:start position:0% +vibrational level higher in that same + + + align:start position:0% +vibrational level higher in that same +electronic State and you can see there's + + align:start position:0% +electronic State and you can see there's + + + align:start position:0% +electronic State and you can see there's +something + + align:start position:0% +something + + + align:start position:0% +something +wrong it's not there's no regular + + align:start position:0% +wrong it's not there's no regular + + + align:start position:0% +wrong it's not there's no regular +spacing of + + align:start position:0% +spacing of + + + align:start position:0% +spacing of +lines there are lines that have been + + align:start position:0% +lines there are lines that have been + + + align:start position:0% +lines there are lines that have been +shifted around and there's extra lines + + align:start position:0% +shifted around and there's extra lines + + + align:start position:0% +shifted around and there's extra lines +there's more lines in here you see how + + align:start position:0% +there's more lines in here you see how + + + align:start position:0% +there's more lines in here you see how +many lines in this lower you see they + + align:start position:0% +many lines in this lower you see they + + + align:start position:0% +many lines in this lower you see they +they're not just there's many closely + + align:start position:0% +they're not just there's many closely + + + align:start position:0% +they're not just there's many closely +spaced + + align:start position:0% +spaced + + + align:start position:0% +spaced +things and that the reason for that is + + align:start position:0% +things and that the reason for that is + + + align:start position:0% +things and that the reason for that is +because uh you're not just seeing the + + align:start position:0% +because uh you're not just seeing the + + + align:start position:0% +because uh you're not just seeing the +bright state but you're seeing the dark + + align:start position:0% +bright state but you're seeing the dark + + + align:start position:0% +bright state but you're seeing the dark +St that because of this accidental + + align:start position:0% +St that because of this accidental + + + align:start position:0% +St that because of this accidental +degeneracy there are Level + + align:start position:0% +degeneracy there are Level + + + align:start position:0% +degeneracy there are Level +shifts and intensity borro you open a + + align:start position:0% +shifts and intensity borro you open a + + + align:start position:0% +shifts and intensity borro you open a +window onto what you're not supposed to + + align:start position:0% + + + + align:start position:0% + +see and some of us still get a thrill + + align:start position:0% +see and some of us still get a thrill + + + align:start position:0% +see and some of us still get a thrill +when we can look through a window we're + + align:start position:0% +when we can look through a window we're + + + align:start position:0% +when we can look through a window we're +not supposed to see + + align:start position:0% +not supposed to see + + + align:start position:0% +not supposed to see +through + + align:start position:0% +through + + + align:start position:0% +through +uh all right + + align:start position:0% +uh all right + + + align:start position:0% +uh all right +so uh we learn about other states + + align:start position:0% +so uh we learn about other states + + + align:start position:0% +so uh we learn about other states +uh we learned about the coupling Matrix + + align:start position:0% +uh we learned about the coupling Matrix + + + align:start position:0% +uh we learned about the coupling Matrix +element we learned about + + align:start position:0% + + + + align:start position:0% + +Dynamics okay so I'd like to say more + + align:start position:0% +Dynamics okay so I'd like to say more + + + align:start position:0% +Dynamics okay so I'd like to say more +about peration + + align:start position:0% +about peration + + + align:start position:0% +about peration +but there's another kind of + + align:start position:0% + + + + align:start position:0% + +perturbation so we might have a bound + + align:start position:0% +perturbation so we might have a bound + + + align:start position:0% +perturbation so we might have a bound +State crossed by a repulsive + + align:start position:0% +State crossed by a repulsive + + + align:start position:0% +State crossed by a repulsive +state so this leads to a b going to A+ + + align:start position:0% +state so this leads to a b going to A+ + + + align:start position:0% +state so this leads to a b going to A+ +B this leads to a Breaking of the + + align:start position:0% +B this leads to a Breaking of the + + + align:start position:0% +B this leads to a Breaking of the +bond pre dissociation so we have a + + align:start position:0% +bond pre dissociation so we have a + + + align:start position:0% +bond pre dissociation so we have a +vibrational level here and a Contin + + align:start position:0% +vibrational level here and a Contin + + + align:start position:0% +vibrational level here and a Contin +vibrational Continuum here and because + + align:start position:0% +vibrational Continuum here and because + + + align:start position:0% +vibrational Continuum here and because +there are coupling Matrix elements + + align:start position:0% +there are coupling Matrix elements + + + align:start position:0% +there are coupling Matrix elements +between the bound State and the + + align:start position:0% +between the bound State and the + + + align:start position:0% +between the bound State and the +Continuum what happens is if we look + + align:start position:0% +Continuum what happens is if we look + + + align:start position:0% +Continuum what happens is if we look +very carefully the bound state gets + + align:start position:0% +very carefully the bound state gets + + + align:start position:0% +very carefully the bound state gets +broadened might get shifted and since + + align:start position:0% +broadened might get shifted and since + + + align:start position:0% +broadened might get shifted and since +there's Continuum above it and below + + align:start position:0% +there's Continuum above it and below + + + align:start position:0% +there's Continuum above it and below +it it is not likely to get pushed one + + align:start position:0% +it it is not likely to get pushed one + + + align:start position:0% +it it is not likely to get pushed one +way or the other by more density of + + align:start position:0% +way or the other by more density of + + + align:start position:0% +way or the other by more density of +States above or below so that level + + align:start position:0% +States above or below so that level + + + align:start position:0% +States above or below so that level +shifts are not important but level + + align:start position:0% +shifts are not important but level + + + align:start position:0% +shifts are not important but level +broadening occurs and again on these + + align:start position:0% +broadening occurs and again on these + + + align:start position:0% +broadening occurs and again on these +pictures that I gave you it + + align:start position:0% +pictures that I gave you it + + + align:start position:0% +pictures that I gave you it +shows + + align:start position:0% + + + + align:start position:0% + +um the second picture is still another + + align:start position:0% +um the second picture is still another + + + align:start position:0% +um the second picture is still another +perturbation but it's a small one but + + align:start position:0% + + + + align:start position:0% + +this third picture um + + align:start position:0% +this third picture um + + + align:start position:0% +this third picture um +shows Something Happening Here is the + + align:start position:0% +shows Something Happening Here is the + + + align:start position:0% +shows Something Happening Here is the +absorption spectrum and here is the + + align:start position:0% +absorption spectrum and here is the + + + align:start position:0% +absorption spectrum and here is the +emission spectrum same band in the + + align:start position:0% +emission spectrum same band in the + + + align:start position:0% +emission spectrum same band in the +absorption it doesn't care if the + + align:start position:0% +absorption it doesn't care if the + + + align:start position:0% +absorption it doesn't care if the +excited state can't live to emit a + + align:start position:0% +excited state can't live to emit a + + + align:start position:0% +excited state can't live to emit a +photon but in the emission spectrum if + + align:start position:0% +photon but in the emission spectrum if + + + align:start position:0% +photon but in the emission spectrum if +the dissociation rate becomes large + + align:start position:0% +the dissociation rate becomes large + + + align:start position:0% +the dissociation rate becomes large +compared to the spontaneous emission + + align:start position:0% +compared to the spontaneous emission + + + align:start position:0% +compared to the spontaneous emission +rate you get no + + align:start position:0% +rate you get no + + + align:start position:0% +rate you get no +fluoresence so this is a + + align:start position:0% +fluoresence so this is a + + + align:start position:0% +fluoresence so this is a +predissociation and it's interesting if + + align:start position:0% +predissociation and it's interesting if + + + align:start position:0% +predissociation and it's interesting if +you look closely that there's a sudden + + align:start position:0% +you look closely that there's a sudden + + + align:start position:0% +you look closely that there's a sudden +drop in intensity and then it picks up + + align:start position:0% +drop in intensity and then it picks up + + + align:start position:0% +drop in intensity and then it picks up +again that the uh the dissociation rate + + align:start position:0% +again that the uh the dissociation rate + + + align:start position:0% +again that the uh the dissociation rate +is uh slowing down as you go away from + + align:start position:0% +is uh slowing down as you go away from + + + align:start position:0% +is uh slowing down as you go away from +the the first J that is hit and so you + + align:start position:0% +the the first J that is hit and so you + + + align:start position:0% +the the first J that is hit and so you +you get uh a large variation in these + + align:start position:0% +you get uh a large variation in these + + + align:start position:0% +you get uh a large variation in these +mixings + + align:start position:0% +mixings + + + align:start position:0% +mixings +so we can still describe Creed + + align:start position:0% +so we can still describe Creed + + + align:start position:0% +so we can still describe Creed +Association by + + align:start position:0% +Association by + + + align:start position:0% +Association by +calculating the electronic Matrix + + align:start position:0% +calculating the electronic Matrix + + + align:start position:0% +calculating the electronic Matrix +element times the rotational Matrix + + align:start position:0% +element times the rotational Matrix + + + align:start position:0% +element times the rotational Matrix +element times the vibrational Matrix + + align:start position:0% +element times the vibrational Matrix + + + align:start position:0% +element times the vibrational Matrix +element and the Complicated new thing is + + align:start position:0% +element and the Complicated new thing is + + + align:start position:0% +element and the Complicated new thing is +we have a bound vibrational State + + align:start position:0% +we have a bound vibrational State + + + align:start position:0% +we have a bound vibrational State +interacting with a Continuum vibrational + + align:start position:0% +interacting with a Continuum vibrational + + + align:start position:0% +interacting with a Continuum vibrational +state but there's still a stationary + + align:start position:0% +state but there's still a stationary + + + align:start position:0% +state but there's still a stationary +phase + + align:start position:0% +phase + + + align:start position:0% +phase +region and that's determining + + align:start position:0% +region and that's determining + + + align:start position:0% +region and that's determining +everything + + align:start position:0% + + + + align:start position:0% + +um and there is another kind of + + align:start position:0% +um and there is another kind of + + + align:start position:0% +um and there is another kind of +perturbation that leads + + align:start position:0% +perturbation that leads + + + align:start position:0% +perturbation that leads +to what we call automization so we have + + align:start position:0% +to what we call automization so we have + + + align:start position:0% +to what we call automization so we have +a process a going to + + align:start position:0% +a process a going to + + + align:start position:0% +a process a going to +a plus plus an + + align:start position:0% +a plus plus an + + + align:start position:0% +a plus plus an +electr this is harder to + + align:start position:0% + + + + align:start position:0% + +draw basically what happens is + + align:start position:0% +draw basically what happens is + + + align:start position:0% +draw basically what happens is +we have an + + align:start position:0% +we have an + + + align:start position:0% +we have an +electron bound to an + + align:start position:0% +electron bound to an + + + align:start position:0% +electron bound to an +ion and the ion can have electronic + + align:start position:0% +ion and the ion can have electronic + + + align:start position:0% +ion and the ion can have electronic +exitation spin + + align:start position:0% +exitation spin + + + align:start position:0% +exitation spin +orbit vibrational exitation rotational + + align:start position:0% +orbit vibrational exitation rotational + + + align:start position:0% +orbit vibrational exitation rotational +and + + align:start position:0% +and + + + align:start position:0% +and +somehow the + + align:start position:0% +somehow the + + + align:start position:0% +somehow the +energy in the ion Finds Its a way to get + + align:start position:0% +energy in the ion Finds Its a way to get + + + align:start position:0% +energy in the ion Finds Its a way to get +into the electron to transfer to the + + align:start position:0% +into the electron to transfer to the + + + align:start position:0% +into the electron to transfer to the +electron and when when it does that the + + align:start position:0% +electron and when when it does that the + + + align:start position:0% +electron and when when it does that the +electron is too much kinetic energy to + + align:start position:0% +electron is too much kinetic energy to + + + align:start position:0% +electron is too much kinetic energy to +remain bound to the ion it falls + + align:start position:0% +remain bound to the ion it falls + + + align:start position:0% +remain bound to the ion it falls +off and there are + + align:start position:0% +off and there are + + + align:start position:0% +off and there are +beautiful mechanisms that describe how + + align:start position:0% +beautiful mechanisms that describe how + + + align:start position:0% +beautiful mechanisms that describe how +this Auto ionization + + align:start position:0% +this Auto ionization + + + align:start position:0% +this Auto ionization +occurs and each of the + + align:start position:0% +occurs and each of the + + + align:start position:0% +occurs and each of the +processes uh electronic spin orbit + + align:start position:0% +processes uh electronic spin orbit + + + align:start position:0% +processes uh electronic spin orbit +vibrational rotational Auto ionization + + align:start position:0% +vibrational rotational Auto ionization + + + align:start position:0% +vibrational rotational Auto ionization +has a nice + + align:start position:0% +has a nice + + + align:start position:0% +has a nice +mechanism \ No newline at end of file diff --git a/Ajar_6MAOLw.txt b/Ajar_6MAOLw.txt new file mode 100644 index 0000000000000000000000000000000000000000..1075b6dbb13d58b8a49463c7beef74dae0eb974f --- /dev/null +++ b/Ajar_6MAOLw.txt @@ -0,0 +1,1291 @@ +align:start position:0% + +we will now take a step towards + + align:start position:0% +we will now take a step towards + + + align:start position:0% +we will now take a step towards +abstraction and discuss the issue of + + align:start position:0% +abstraction and discuss the issue of + + + align:start position:0% +abstraction and discuss the issue of +convergence of random variables let us + + align:start position:0% +convergence of random variables let us + + + align:start position:0% +convergence of random variables let us +look at the weak law of large numbers it + + align:start position:0% +look at the weak law of large numbers it + + + align:start position:0% +look at the weak law of large numbers it +tells us that with high probability the + + align:start position:0% +tells us that with high probability the + + + align:start position:0% +tells us that with high probability the +sample mean falls close to the true mean + + align:start position:0% +sample mean falls close to the true mean + + + align:start position:0% +sample mean falls close to the true mean +as n goes to infinity we would like to + + align:start position:0% +as n goes to infinity we would like to + + + align:start position:0% +as n goes to infinity we would like to +interpret the statement by saying that + + align:start position:0% +interpret the statement by saying that + + + align:start position:0% +interpret the statement by saying that +the sample mean converges to the true + + align:start position:0% +the sample mean converges to the true + + + align:start position:0% +the sample mean converges to the true +mean however before we can make such a + + align:start position:0% +mean however before we can make such a + + + align:start position:0% +mean however before we can make such a +statement we should first define + + align:start position:0% +statement we should first define + + + align:start position:0% +statement we should first define +carefully the word converges and we need + + align:start position:0% +carefully the word converges and we need + + + align:start position:0% +carefully the word converges and we need +a notion of convergence that refers to + + align:start position:0% +a notion of convergence that refers to + + + align:start position:0% +a notion of convergence that refers to +convergence of random variables here is + + align:start position:0% +convergence of random variables here is + + + align:start position:0% +convergence of random variables here is +the definition suppose that we have a + + align:start position:0% +the definition suppose that we have a + + + align:start position:0% +the definition suppose that we have a +sequence of random variables that are + + align:start position:0% +sequence of random variables that are + + + align:start position:0% +sequence of random variables that are +not necessarily independent we say that + + align:start position:0% +not necessarily independent we say that + + + align:start position:0% +not necessarily independent we say that +this sequence of random variables + + align:start position:0% +this sequence of random variables + + + align:start position:0% +this sequence of random variables +converges in probability that's the + + align:start position:0% +converges in probability that's the + + + align:start position:0% +converges in probability that's the +particular notion of convergence we're + + align:start position:0% +particular notion of convergence we're + + + align:start position:0% +particular notion of convergence we're +defining it converges to a certain + + align:start position:0% +defining it converges to a certain + + + align:start position:0% +defining it converges to a certain +number if the following is true no + + align:start position:0% +number if the following is true no + + + align:start position:0% +number if the following is true no +matter what epsilon is as long as it is + + align:start position:0% +matter what epsilon is as long as it is + + + align:start position:0% +matter what epsilon is as long as it is +a positive number the probability that + + align:start position:0% +a positive number the probability that + + + align:start position:0% +a positive number the probability that +the random variable falls far from this + + align:start position:0% +the random variable falls far from this + + + align:start position:0% +the random variable falls far from this +number that is epsilon or further away + + align:start position:0% +number that is epsilon or further away + + + align:start position:0% +number that is epsilon or further away +from that number that probability + + align:start position:0% +from that number that probability + + + align:start position:0% +from that number that probability +converges to 0 as n increases that is as + + align:start position:0% +converges to 0 as n increases that is as + + + align:start position:0% +converges to 0 as n increases that is as +n increases there is higher and higher + + align:start position:0% +n increases there is higher and higher + + + align:start position:0% +n increases there is higher and higher +probability that Y n will be close to + + align:start position:0% +probability that Y n will be close to + + + align:start position:0% +probability that Y n will be close to +this particular number a this is the + + align:start position:0% +this particular number a this is the + + + align:start position:0% +this particular number a this is the +notion of convergence that we have + + align:start position:0% +notion of convergence that we have + + + align:start position:0% +notion of convergence that we have +defined and notice that this notion of + + align:start position:0% +defined and notice that this notion of + + + align:start position:0% +defined and notice that this notion of +convergence corresponds exactly to what + + align:start position:0% +convergence corresponds exactly to what + + + align:start position:0% +convergence corresponds exactly to what +is happening in the weak law of large + + align:start position:0% +is happening in the weak law of large + + + align:start position:0% +is happening in the weak law of large +numbers and so in particular we can + + align:start position:0% +numbers and so in particular we can + + + align:start position:0% +numbers and so in particular we can +describe the weak law of large numbers + + align:start position:0% +describe the weak law of large numbers + + + align:start position:0% +describe the weak law of large numbers +as saying that m and the sample mean + + align:start position:0% +as saying that m and the sample mean + + + align:start position:0% +as saying that m and the sample mean +converges to MU as n goes to infinity + + align:start position:0% +converges to MU as n goes to infinity + + + align:start position:0% +converges to MU as n goes to infinity +but in a particular sense in the sense + + align:start position:0% +but in a particular sense in the sense + + + align:start position:0% +but in a particular sense in the sense +of convergence in probability let us now + + align:start position:0% +of convergence in probability let us now + + + align:start position:0% +of convergence in probability let us now +try to understand a little better what + + align:start position:0% +try to understand a little better what + + + align:start position:0% +try to understand a little better what +convergence in probability really + + align:start position:0% +convergence in probability really + + + align:start position:0% +convergence in probability really +amounts to and we will do that by making + + align:start position:0% +amounts to and we will do that by making + + + align:start position:0% +amounts to and we will do that by making +a comparison with the ordinary notion of + + align:start position:0% +a comparison with the ordinary notion of + + + align:start position:0% +a comparison with the ordinary notion of +convergence of real numbers + + align:start position:0% +convergence of real numbers + + + align:start position:0% +convergence of real numbers +when we're dealing with convergence of + + align:start position:0% +when we're dealing with convergence of + + + align:start position:0% +when we're dealing with convergence of +numbers we start with a sequence of + + align:start position:0% +numbers we start with a sequence of + + + align:start position:0% +numbers we start with a sequence of +numbers and we are interested in the + + align:start position:0% +numbers and we are interested in the + + + align:start position:0% +numbers and we are interested in the +statement that this sequence converges + + align:start position:0% +statement that this sequence converges + + + align:start position:0% +statement that this sequence converges +to a certain limit what does that mean + + align:start position:0% +to a certain limit what does that mean + + + align:start position:0% +to a certain limit what does that mean +what we mean is that the elements of the + + align:start position:0% +what we mean is that the elements of the + + + align:start position:0% +what we mean is that the elements of the +sequence eventually that is when n is + + align:start position:0% +sequence eventually that is when n is + + + align:start position:0% +sequence eventually that is when n is +large enough we'll get and stay + + align:start position:0% +large enough we'll get and stay + + + align:start position:0% +large enough we'll get and stay +arbitrarily close to this particular + + align:start position:0% +arbitrarily close to this particular + + + align:start position:0% +arbitrarily close to this particular +number a which is the limit in terms of + + align:start position:0% +number a which is the limit in terms of + + + align:start position:0% +number a which is the limit in terms of +a picture here is a the limit here is n + + align:start position:0% +a picture here is a the limit here is n + + + align:start position:0% +a picture here is a the limit here is n +we take a small band around this number + + align:start position:0% +we take a small band around this number + + + align:start position:0% +we take a small band around this number +a and what we require is that the + + align:start position:0% +a and what we require is that the + + + align:start position:0% +a and what we require is that the +elements of the sequence eventually get + + align:start position:0% +elements of the sequence eventually get + + + align:start position:0% +elements of the sequence eventually get +within this band around the number a + + align:start position:0% +within this band around the number a + + + align:start position:0% +within this band around the number a +they might get outside the band get + + align:start position:0% +they might get outside the band get + + + align:start position:0% +they might get outside the band get +inside again but eventually that is + + align:start position:0% +inside again but eventually that is + + + align:start position:0% +inside again but eventually that is +after some time the elements of the + + align:start position:0% +after some time the elements of the + + + align:start position:0% +after some time the elements of the +sequence will only stay inside this band + + align:start position:0% +sequence will only stay inside this band + + + align:start position:0% +sequence will only stay inside this band +now to translate this into a more formal + + align:start position:0% +now to translate this into a more formal + + + align:start position:0% +now to translate this into a more formal +mathematical statement which is the + + align:start position:0% +mathematical statement which is the + + + align:start position:0% +mathematical statement which is the +mathematical definition of the notion of + + align:start position:0% +mathematical definition of the notion of + + + align:start position:0% +mathematical definition of the notion of +convergence we have the following if I + + align:start position:0% +convergence we have the following if I + + + align:start position:0% +convergence we have the following if I +give you some epsilon epsilon could be a + + align:start position:0% +give you some epsilon epsilon could be a + + + align:start position:0% +give you some epsilon epsilon could be a +very small number I form a band around a + + align:start position:0% +very small number I form a band around a + + + align:start position:0% +very small number I form a band around a +that goes from a minus epsilon to a plus + + align:start position:0% +that goes from a minus epsilon to a plus + + + align:start position:0% +that goes from a minus epsilon to a plus +Epsilon what I want is that there exists + + align:start position:0% +Epsilon what I want is that there exists + + + align:start position:0% +Epsilon what I want is that there exists +a certain time and zero in this picture + + align:start position:0% +a certain time and zero in this picture + + + align:start position:0% +a certain time and zero in this picture +and zero would be here such that for all + + align:start position:0% +and zero would be here such that for all + + + align:start position:0% +and zero would be here such that for all +times after n zero our sequence stays + + align:start position:0% +times after n zero our sequence stays + + + align:start position:0% +times after n zero our sequence stays +within Epsilon from a that is our + + align:start position:0% +within Epsilon from a that is our + + + align:start position:0% +within Epsilon from a that is our +sequence stays inside this band now let + + align:start position:0% +sequence stays inside this band now let + + + align:start position:0% +sequence stays inside this band now let +us move to the case of random variables + + align:start position:0% +us move to the case of random variables + + + align:start position:0% +us move to the case of random variables +and see what convergence in probability + + align:start position:0% +and see what convergence in probability + + + align:start position:0% +and see what convergence in probability +is talking about here instead of a + + align:start position:0% +is talking about here instead of a + + + align:start position:0% +is talking about here instead of a +sequence of numbers we have a sequence + + align:start position:0% +sequence of numbers we have a sequence + + + align:start position:0% +sequence of numbers we have a sequence +of random variables and we're interested + + align:start position:0% +of random variables and we're interested + + + align:start position:0% +of random variables and we're interested +in the meaning of the convergence of the + + align:start position:0% +in the meaning of the convergence of the + + + align:start position:0% +in the meaning of the convergence of the +sequence of run + + align:start position:0% +sequence of run + + + align:start position:0% +sequence of run +variables to a particular number in + + align:start position:0% +variables to a particular number in + + + align:start position:0% +variables to a particular number in +words what this means is that if I fix a + + align:start position:0% +words what this means is that if I fix a + + + align:start position:0% +words what this means is that if I fix a +certain epsilon as in this picture then + + align:start position:0% +certain epsilon as in this picture then + + + align:start position:0% +certain epsilon as in this picture then +the probability that the random variable + + align:start position:0% +the probability that the random variable + + + align:start position:0% +the probability that the random variable +falls outside this band converges to + + align:start position:0% +falls outside this band converges to + + + align:start position:0% +falls outside this band converges to +zero so the picture would be as follows + + align:start position:0% + + + + align:start position:0% + +we have again or limit we fix some + + align:start position:0% +we have again or limit we fix some + + + align:start position:0% +we have again or limit we fix some +epsilon which could be an arbitrarily + + align:start position:0% +epsilon which could be an arbitrarily + + + align:start position:0% +epsilon which could be an arbitrarily +small number for any fixed choice of + + align:start position:0% +small number for any fixed choice of + + + align:start position:0% +small number for any fixed choice of +epsilon we take this band and for any + + align:start position:0% +epsilon we take this band and for any + + + align:start position:0% +epsilon we take this band and for any +given n we look into the probability + + align:start position:0% +given n we look into the probability + + + align:start position:0% +given n we look into the probability +that a random variable falls inside that + + align:start position:0% +that a random variable falls inside that + + + align:start position:0% +that a random variable falls inside that +band so if I am to draw the distribution + + align:start position:0% +band so if I am to draw the distribution + + + align:start position:0% +band so if I am to draw the distribution +of our random variable the distribution + + align:start position:0% +of our random variable the distribution + + + align:start position:0% +of our random variable the distribution +might be something like this so there is + + align:start position:0% +might be something like this so there is + + + align:start position:0% +might be something like this so there is +a certain probability that it falls + + align:start position:0% +a certain probability that it falls + + + align:start position:0% +a certain probability that it falls +outside this band but when n becomes + + align:start position:0% +outside this band but when n becomes + + + align:start position:0% +outside this band but when n becomes +large this probability of falling + + align:start position:0% +large this probability of falling + + + align:start position:0% +large this probability of falling +outside this band becomes very small so + + align:start position:0% +outside this band becomes very small so + + + align:start position:0% +outside this band becomes very small so +the probability of falling outside the + + align:start position:0% +the probability of falling outside the + + + align:start position:0% +the probability of falling outside the +band becomes tiny so the bulk of the + + align:start position:0% +band becomes tiny so the bulk of the + + + align:start position:0% +band becomes tiny so the bulk of the +distribution that is most of the + + align:start position:0% +distribution that is most of the + + + align:start position:0% +distribution that is most of the +probability is concentrated inside this + + align:start position:0% +probability is concentrated inside this + + + align:start position:0% +probability is concentrated inside this +band and this is true no matter how + + align:start position:0% +band and this is true no matter how + + + align:start position:0% +band and this is true no matter how +small epsilon is if I take a much + + align:start position:0% +small epsilon is if I take a much + + + align:start position:0% +small epsilon is if I take a much +narrower band around a I still want all + + align:start position:0% +narrower band around a I still want all + + + align:start position:0% +narrower band around a I still want all +the probability to be eventually + + align:start position:0% +the probability to be eventually + + + align:start position:0% +the probability to be eventually +concentrated inside that band of course + + align:start position:0% +concentrated inside that band of course + + + align:start position:0% +concentrated inside that band of course +it might take longer it might take a + + align:start position:0% +it might take longer it might take a + + + align:start position:0% +it might take longer it might take a +larger value of n but I want that when n + + align:start position:0% +larger value of n but I want that when n + + + align:start position:0% +larger value of n but I want that when n +is very large the bulk of the + + align:start position:0% +is very large the bulk of the + + + align:start position:0% +is very large the bulk of the +distribution is again concentrated + + align:start position:0% +distribution is again concentrated + + + align:start position:0% +distribution is again concentrated +inside this narrow band so inwards + + align:start position:0% +inside this narrow band so inwards + + + align:start position:0% +inside this narrow band so inwards +convergence in probability means that + + align:start position:0% +convergence in probability means that + + + align:start position:0% +convergence in probability means that +almost all of the probability mass of + + align:start position:0% +almost all of the probability mass of + + + align:start position:0% +almost all of the probability mass of +the random variable Y n when n is large + + align:start position:0% +the random variable Y n when n is large + + + align:start position:0% +the random variable Y n when n is large +that probability mass gets concentrated + + align:start position:0% +that probability mass gets concentrated + + + align:start position:0% +that probability mass gets concentrated +within a narrow band around the limit of + + align:start position:0% +within a narrow band around the limit of + + + align:start position:0% +within a narrow band around the limit of +the random variable + + align:start position:0% +the random variable + + + align:start position:0% +the random variable +we finally point out a few useful + + align:start position:0% +we finally point out a few useful + + + align:start position:0% +we finally point out a few useful +properties of convergence in probability + + align:start position:0% +properties of convergence in probability + + + align:start position:0% +properties of convergence in probability +that parallel well-known properties of + + align:start position:0% +that parallel well-known properties of + + + align:start position:0% +that parallel well-known properties of +convergence of sequences suppose that we + + align:start position:0% +convergence of sequences suppose that we + + + align:start position:0% +convergence of sequences suppose that we +have a sequence of random variables that + + align:start position:0% +have a sequence of random variables that + + + align:start position:0% +have a sequence of random variables that +converges in probability to a certain + + align:start position:0% +converges in probability to a certain + + + align:start position:0% +converges in probability to a certain +number a and another sequence that + + align:start position:0% +number a and another sequence that + + + align:start position:0% +number a and another sequence that +converges in probability to some other + + align:start position:0% +converges in probability to some other + + + align:start position:0% +converges in probability to some other +number B we do not make any assumptions + + align:start position:0% +number B we do not make any assumptions + + + align:start position:0% +number B we do not make any assumptions +about independence we do not assume that + + align:start position:0% +about independence we do not assume that + + + align:start position:0% +about independence we do not assume that +the accents are independent of each + + align:start position:0% +the accents are independent of each + + + align:start position:0% +the accents are independent of each +other we do not assume that the sequence + + align:start position:0% +other we do not assume that the sequence + + + align:start position:0% +other we do not assume that the sequence +of accents is independent of Y n we then + + align:start position:0% +of accents is independent of Y n we then + + + align:start position:0% +of accents is independent of Y n we then +have the following properties if G is a + + align:start position:0% +have the following properties if G is a + + + align:start position:0% +have the following properties if G is a +continuous function then the function of + + align:start position:0% +continuous function then the function of + + + align:start position:0% +continuous function then the function of +the random variables converges to the + + align:start position:0% +the random variables converges to the + + + align:start position:0% +the random variables converges to the +function of the number so for example + + align:start position:0% +function of the number so for example + + + align:start position:0% +function of the number so for example +the sequence of random variables xn + + align:start position:0% +the sequence of random variables xn + + + align:start position:0% +the sequence of random variables xn +squared is going to converge to a + + align:start position:0% +squared is going to converge to a + + + align:start position:0% +squared is going to converge to a +squared another fact is that the sum of + + align:start position:0% +squared another fact is that the sum of + + + align:start position:0% +squared another fact is that the sum of +these two random variables converges to + + align:start position:0% +these two random variables converges to + + + align:start position:0% +these two random variables converges to +the sum of their limits both of these + + align:start position:0% +the sum of their limits both of these + + + align:start position:0% +the sum of their limits both of these +properties are analogous to what happens + + align:start position:0% +properties are analogous to what happens + + + align:start position:0% +properties are analogous to what happens +with ordinary convergence of numbers and + + align:start position:0% +with ordinary convergence of numbers and + + + align:start position:0% +with ordinary convergence of numbers and +they tell us that in some sense + + align:start position:0% +they tell us that in some sense + + + align:start position:0% +they tell us that in some sense +convergence in probability is not a very + + align:start position:0% +convergence in probability is not a very + + + align:start position:0% +convergence in probability is not a very +different notion we will not prove those + + align:start position:0% +different notion we will not prove those + + + align:start position:0% +different notion we will not prove those +properties at this point but they're + + align:start position:0% +properties at this point but they're + + + align:start position:0% +properties at this point but they're +useful to know however there's an + + align:start position:0% +useful to know however there's an + + + align:start position:0% +useful to know however there's an +important caveat xn might converge to a + + align:start position:0% +important caveat xn might converge to a + + + align:start position:0% +important caveat xn might converge to a +certain number in probability + + align:start position:0% +certain number in probability + + + align:start position:0% +certain number in probability +however the expected value of xn does + + align:start position:0% +however the expected value of xn does + + + align:start position:0% +however the expected value of xn does +not necessarily converge to that same + + align:start position:0% +not necessarily converge to that same + + + align:start position:0% +not necessarily converge to that same +limit so convergence of random variables + + align:start position:0% +limit so convergence of random variables + + + align:start position:0% +limit so convergence of random variables +does not imply convergence of + + align:start position:0% +does not imply convergence of + + + align:start position:0% +does not imply convergence of +expectations and we will be seeing an + + align:start position:0% +expectations and we will be seeing an + + + align:start position:0% +expectations and we will be seeing an +example where this convergence does not + + align:start position:0% +example where this convergence does not + + + align:start position:0% +example where this convergence does not +take place \ No newline at end of file diff --git a/BGL8we3QUxI.txt b/BGL8we3QUxI.txt new file mode 100644 index 0000000000000000000000000000000000000000..36a9595b0f5f67d2c059d0322c0d1dabf3e98b5e --- /dev/null +++ b/BGL8we3QUxI.txt @@ -0,0 +1,4425 @@ +The following +content is provided + +under a Creative +Commons license. + +Your support will help MIT +OpenCourseWare continue + +to offer high-quality +educational resources for free. + +To make a donation or to +view additional materials + +from hundreds of MIT courses, +visit MIT OpenCourseWare + +at ocw.mit.edu. + +PROFESSOR: So welcome back. + +Today, we're going to look +at the modular synthesizer. + +And our area of focus +right now is still + +looking at musical interfaces. + +A lot of people present +the modular synthesizer + +in the context of basic +synthesis techniques + +and the development of +musical instruments. + +I think it's very +useful for us to think + +of the modular synthesizer as +a type of musical interface, + +and particularly the +interface available + +through the creative patching +and combination of modules. + +So what we're going +to do is we're + +going to look at a little bit of +the history of the development + +of modular synthesizers, +starting with the giant RCA + +synth, and then +moving on to the Moog. + +We're going to spend a little +time with the basic Moog design + +and look at some of the +basic synthesis techniques. + +We're going to do +that by looking + +at the emulation of +virtual Moog that we + +have available through +Arturia's very nice virtual Moog + +instrument plug-in, which +is going to give us a way + +to hear some of the sounds +and see some of the approaches + +to patching this instrument. + +And then next time we meet in +workshop mode next Tuesday, + +we're going to build some +similar designs in PD + +using the Martingale +Library and explore + +some of these +approaches, as well. + +We're going to listen to some +music and then if we get to it, + +talk about some +semi-modular synths. + +And see the design go from +fully modular synthesizers + +to semi-modular and +non-modular synthesizers, which + +is a valuable trajectory to see. + +So coming up on the horizon, we +have a brief quiz on Thursday. + +Keep that in mind. + +Your music technology +case studies-- + +the draft is due on Tuesday. + +If you have any questions about +this as you approach this, + +feel free to drop me +an email or the like. + +And that's it for now. + +Any questions? + +OK. + +So now with the +modular synthesizer, + +we see numerous things +start to come together. + +We saw in the early studios +used by Varese, by Stockhausen, + +and others, this cobbling +together of various components + +and interconnecting them +into sound-producing devices. + +We see with the +modular synthesizer + +these components +start to solidify + +into a single common +collection of entities. + +With these semi-modular +designs, we + +see this solidification +happen even more. + +And the designs solidify +into a single common thing. + +There wasn't anything shockingly +new about the technologies used + +in the modular synthesizer. + +Again, they were +technologies that + +had been around +for 10 or 20 years. + +But really, the +interface, and the design, + +and the integration of these +components, in my view, + +was the really important thing. + +Voltage control-- the ability +to interconnect and control + +these devices with +voltages-- was really + +the key technology that made +this synthesizer more flexible, + +more powerful, and more +creative for the operator. + +Now we start with the RCA +synthesizer, which isn't really + +a modular synthesizer. + +To my knowledge, this device +had a fairly fixed signal path. + +So it wasn't really modular. + +It had components. + +But you couldn't +interconnect the components + +with patch cords. + +You couldn't radically +change the type of sounds + +that it made. + +Now this synthesizer came +in two different forms. + +There was the first one, which +later became known as the Mark + +I and then the Mark II, +the later version of this. + +This synthesizer was the result +of quite a bit of research + +by Olson and Belar, +who were working + +at RCA for a number of years. + +The Holmes text nicely +describes their early research + +with music synthesis +technologies. + +Does anybody recall +what they were + +trying to do in the +beginning-- Olson and Belar. + +Their first attempt +at synthesis was + +directed towards this +certain activity. + +Anybody recall? + +They were trying to synthesize +Steven Walter pop tunes-- pop + +melodies-- basic melodies, +using essentially Markov chains. + +And they were trying to +create a machine that + +could compose simple melodies +by analyzing basic tunes + +and then re-synthesizing them. + +In that process, they +developed some technologies + +for creating +oscillators and filters. + +And that led to their +first RCA synthesizer. + +So this device used essentially +tuning-fork-based oscillators. + +So their basic oscillator +was a tuning fork + +that was set in motion and +picked up electromagnetically. + +And that signal was then divided +to shift into different octaves + +and transformed into a square +wave to create a rich tone. + +And then they filtered +that tone to create + +the variety of timbres that +the instrument could make. + +The device featured +a number of filters, + +as well-- high- and low-pass +filters and this really kind + +of bizarre resonator +chain, which + +is an interesting +selective filter. + +This image here is from +their first publication + +on the synthesizer from 1955. + +And it's also reproduced +in the Holmes book. + +We can see the basic way +that the synthesizer worked. + +Information was encoded on +something kind of like a piano + +roll, but just storing +control information + +in a binary representation. + +Here, rather than +using a vacuum, + +brushes are used to pick up +when an opening in the hole + +was to trigger a circuit. + +The frequency source +here is those oscillators + +controlled by tuning forks. + +And that signal is then +split by the octiver. + +And then it has the +frequency glider, + +which allows the transition +between pitches, the growth, + +and decay, which is a fancy +name for an envelope generator. + +Or not fancy, I guess-- +historic-- various high-pass, + +low-pass filters, +volume control, + +low-frequency +modulator, probably + +for adding vibrato or other +slow changes to the sound. + +Resonator change-- +that's that unique filter + +I was talking about-- +timbre control, probably + +additional filters. + +Or I'm not exactly sure what +that last component did. + +But that's something to look at. + +And then finally, all going +to a nice record cutter, + +which allowed you +to record the sound. + +So there were two +nearly identical voices + +that could be used and +controlled by this paper roll. + +So partly out of Olson and +Belar's earlier research + +in synthesizing pop tunes, +they approached a synthesizer + +as a device that needed to be +controlled, not by a keyboard, + +not by some other +type of interface, + +but by a type of notation. + +And their notation was this +punched-hole paper record, + +which again, is kind of like +a piano roll but different. + +Because rather than a one-to-one +relationship with parameters + +and their values, +these are essentially + +three- and four-bit codes that +determine frequency, octave, + +timbre, the envelope growth +and decay, and volume. + +So frequency is determined by +these four on-and-off switches, + +which give us 16 +possible values. + +But they only used 12. + +Octave could be selected. + +Similarly here, timbre, the +envelope, volume, et cetera. + +This roll right there shows +us the necessary information + +to encode these six pitches. + +So you can imagine working +with this device would + +be a little tedious. + +But it offered explicit, +complete control. + +This nice diagram, also +from that original article, + +shows us a massive +simplification of the device, + +going from reading the +roll, to the two synthesizer + +channels, mixer, amplifier, and +then a direct-to-disk cutting + +lathe. + +Some notable thing +about this-- it + +was really the first +attempt to parameterize + +musical information in a very +rigorous and complete way. + +We saw with the player +piano an earlier attempt + +at parameterization. + +But here, we're starting +to parameterize timbre, + +amplitude envelopes, and +volume and level controls + +at a greater degree than we +had with the player piano. + +Also important about +this instrument + +is it was not designed +for performance. + +It was really designed +as a machine where + +you composed in +advance and played back + +what you had notated. + +That was the Mark +I. The Mark II was + +housed at Princeton University. + +And that started a relationship +with Columbia and Princeton + +University, which led to +Columbia and Princeton + +getting a grant from the +Rockefeller Foundation + +to buy the second version of +this synth-- the RCA Mark II. + +This synth was very +similar to the Mark I, + +except for it added a +white-noise generator, which + +was useful for creating a +variety of noisier percussive + +sounds. + +It had four voices +instead of two. + +It had a microphone input. + +And it had some variable +frequency oscillators. + +Similar to the RCA Mark I, it +was a room-sized giant beast + +of a synthesizer. + +In this picture, we can +see the disk cutters here. + +We can see, also, some tape. + +Eventually, they did +add tape machines. + +And we can see the +paper readers there. + +Notice that we don't see, +really, a patch bay or patch + +cords. + +This was a modular synthesizer +in that had modules. + +But it wasn't freely +interconnectable in the way + +that we later find with our +Moog and Buchla synthesizers. + +Now I sent you guys the link +to this demo recording, which + +has this great narrator +helping us along the way. + +This demo record +was made in 1955. + +I believe it was a +recording of the Mark II. + +The reason why is because +in this demonstration, + +they use a filtered white noise. + +And I think this is a +very nice example where + +they tried to synthesize the +sound of a complete dance band. + +So they had four voices. + +So they used some of the +voices for bass, percussion, + +and melody. + +Let's listen to +a little of this. + +[HIGH-PITCHED SYNTHESIZER BEEPS] + +PROFESSOR: That's +the high-hat sound. + +[LOW-PITCHED SYNTHESIZER BEEPS] + +PROFESSOR: And that's the bass. + +[SYNTHESIZER] + +PROFESSOR: And here's +everything altogether. + +[VIDEO PLAYBACK] + +-We can also +synthesize a part where + +each tone has a rapid growth +and slow decay, like this. + +[END VIDEO PLAYBACK] + +PROFESSOR: Let's go +back to that dance band. + +[LOW-PITCHED SYNTHESIZER BEEPS] + +PROFESSOR: Come on. + +[SYNTHESIZED MUSIC] + +PROFESSOR: There we go. + +Notice the white noise being +used for the snare-like sound + +there. + +So as this demo record shows, +and as the history of Olson + +and Belar's work +shows, they were + +very interested in +using the synthesizer + +to generate pop music, +which is interesting. + +Because what it became used +for was not popular music, + +but music of composers +like Milton Babbitt, Mario + +Davidovsky, and other +composers working + +at the Columbia-Princeton +studios. + +One of our listenings for today +was "Philomel," Babbitt's 1964 + +composition that used +the RCA synthesizer. + +Let's listen to a +little bit of this + +to remind you guys +what this sounds like. + +[MUSIC -- MILTON BABBITT, + "PHILOMEL"] + +PROFESSOR: So +there's three sources + +of sound in this composition. + +What are they-- three +sources of sound? + +AUDIENCE: There's the voice. + +PROFESSOR: Right, +the live voice. + +AUDIENCE: There's +the synthesizer. + +Not sure what the third was. + +PROFESSOR: Anybody +notice or recall? + +There's also pre-recorded voice. + +So there's some tape-recorded +and processed voice sounds + +in here, which are used to +create some very nice distance + +echo and some +depth to the voice. + +And actually in my view, one +of the most interesting things + +about this piece is +how the tape part + +blends with the synthesis +and acts as an intermediary. + +Thoughts about this piece? + +AUDIENCE: It's very sporadic. + +PROFESSOR: Sporadic-- what +do you mean, sporadic? + +AUDIENCE: Very jagged. + +I don't know. + +It's not really-- they +follow a certain pattern. + +But there's not a ton of tune. + +PROFESSOR: Yeah, there's this +jagged, jerky, gestural shape + +to a lot of the musical parts. + +And that's clear in the voice +and also in the synthesizer + +parts. + +AUDIENCE: As the piece +goes on, the voice + +smooths out a +little bit, though, + +if I remember correctly. + +And then the synthesizer's still +doing the jagged [INAUDIBLE]. + +So it has the background +interjections, I guess. + +It seems like longer stretches. + +AUDIENCE: Yeah. + +PROFESSOR: Yeah, let's +jump to the end in here. + +[MUSIC -- MILTON BABBITT, + "PHILOMEL"] + +PROFESSOR: Now Babbitt was +using a method of organization + +that we have talked +about previously. + +What was that method +of organization? + +AUDIENCE: Serialism. + +PROFESSOR: Serialism, or +the 12-tone technique. + +Did the RCA synthesizer +provide facilities + +for 12-tone composers? + +Was it well suited for that? + +I mean, Olson and Belar wanted +to use it to do popular music. + +AUDIENCE: You had absolute +control over everything, right? + +So it was perfect. + +PROFESSOR: Right. + +All your parameters +were fixed on the roll. + +So you could compose very +carefully crafted lines + +in a very organized way. + +And that's very much +what we hear here. + +It's kind of, I think, ironic +in that Olson and Belar imagined + +this instrument +originally to create + +an endless variety +of pop tunes to sell + +in the commercial market. + +And of course, it +ended up being used + +to create some very esoteric, +non-commercial music + +in the end. + +And that's one of +our many examples + +of unintended consequences +of certain technologies. + +Other comments or +reflections on this piece? + +AUDIENCE: I thought +it was really + +cool to use the +operatic voice with it, + +as opposed to other +singing styles. + +Because in conjunction +with the synthesizer, + +the strange timbre +of operatic singing + +became this thing that +was more like a thing + +to listen to than typically +what operatic singing is about. + +PROFESSOR: Yeah, +that's interesting. + +For me, the really striking +thing is the vibrato. + +Because the vibrato +is really, really + +wide-- contrast between that +wide vibrato and the more flat + +tones we're getting +out of the synthesizer. + +Are you hearing +something else, as well? + +AUDIENCE: No, that's +the sort of thing. + +But then also in the +tape-modulated parts. + +Because he speeds her +up and slows her down. + +And so this thing happens +with the vibrato right + +where they like. + +It was very tight, or +even looser and lower. + +And there's this +really, I think, + +great interplay between that +and the synthesized sounds. + +PROFESSOR: Yeah, I agree. + +Yep. + +AUDIENCE: Yeah, +the sound I heard + +reminded me a lot +of science fiction. + +PROFESSOR: Uh-huh. [LAUGHS] + +AUDIENCE: There seems +to be a common thread + +about that recording. + +PROFESSOR: Yeah. + +Well, a lot of the early +sounds of early synthesizers + +were used in science fiction and +film, since Forbidden Planet, + +and even before that +with the theremin. + +The connection has been +there for some time. + +We don't hear a lot of +variety of timbres and colors + +with the synthesizer. + +A lot of it is sinusoidal +or filtered waveforms. + +So there's not a huge variety +of sounds out of the synth. + +But it didn't provide a +tremendous amount of control, + +as we can tell by looking +at the control information + +available on the tape. + +AUDIENCE: Do you know +anything about how + +it was serialed, whether he +used all of his parameters + +in the serial way? + +I was trying to parse it +out, and I had no idea. + +PROFESSOR: Yeah. + +I mean, it's worth +looking at further. + +I suspect, given +Babbitt's inclinations, + +that both pitch and the other +parameters were serialized. + +So it's very likely +he had the opportunity + +to serialize envelopes +and serialize + +the timbre controls +of the synth. + +So I think it's very +likely that he probably + +did, which is similar to an +approach taken by Stockhausen, + +who was rigorously exploring +some of these things. + +But with the RCA synthesizer, +this became very notatable + +in a way that wasn't +possible before. + +Do you have another comment? + +OK. + +So two innovators followed +the RCA synthesizer + +with devices that were +more flexible than the RCA + +synthesizer. + +They were more flexible in +that they allowed the operator + +to reconnect the +modules in various ways. + +Rather than that fixed sequence +of oscillator, filter, et + +cetera, these devices +allowed the operator + +to interconnect them in a +variety of different ways + +and also allowed the +operator to control them + +in a variety of different +ways, not with punched paper + +but with various types +of input devices. + +Buchla generally gets credit +for coming a little bit + +before Moog. + +His devices were very diverse +and often custom-designed + +for particular people, +particular studios. + +His interest as a +composer himself + +was in creating diverse +and unique instruments, + +not really in creating +a commercial market + +for the synthesizer. + +So he not only explored a wide +variety of different modules + +that use noise and +randomness in different ways, + +but also various +types of input devices + +other than the keyboard. + +And our readings for today +emphasize the point about how + +Buchla initially didn't want +a keyboard control for his + +instrument, and +Moog embraced that, + +which is an issue we'll talk +about when we talk about + +the [? Pinchen-Trocho ?] +reading. + +In 1965, he releases +the Buchla Box + +without a keyboard-- a +very popular instrument. + +1970, he has this 200 +series Electric Music Box, + +which you can see there. + +Also doesn't have a +keyboard, but has a variety + +of sliders, knobs, and +other interface components. + +In the '70s, he released +some portable devices. + +This one, although apparently I +think Holmes says that only 200 + +of these were made-- wouldn't +you like one of these? + +He did use a keyboard at times. + +But notice that this is a +touch-sensitive keyboard + +and probably does some +things we wouldn't expect. + +A small, portable +modular synthesizer-- + +if you can find one +of these, get it. + +[LAUGHS] + +Buchla is still +making synthesizers. + +They're very expensive. + +But they really offer +some unique designs. + +Looking at his designs-- +you can go to his website-- + +are really fascinating, creative +approaches to the synthesizer. + +Buchla is a separate +thread from that of Moog. + +Because Moog's instruments +were dedicated to meeting the + +needs-- the demands-- +of musicians. + +Our readings make +that very clear. + +He worked with musicians +in a variety of ways. + +He invited musicians +to come to his factory + +and explore his instruments. + +He adapted his instruments +to the demands of musicians + +in order to meet their needs, +and really, through that, + +made a very successful +commercial instrument. + +Now we've already +talked about how + +Moog got started with +the theremin as a kid, + +creating theremin +kits in his garage. + +In 1954, he published this +article in Radio and Television + +News about his design for +a tube-based theremin. + +This article's great. + +You can check it out online. + +It also has the whole schematic +diagram for the circuit. + +At this time in +the '40s and '50s, + +there was this whole +kit-bit building culture, + +and a lot of interest +in building theremin. + +So his design +became very popular + +and attracted a +lot of attention. + +He published another +article in 1961 + +using a transistor-based +theremin that was actually + +featured on the cover +of this magazine + +and also got him a +lot of attention. + +He, by then, had a business. + +He and his dad were selling +theremins out of their garage-- + +theremin kits. + +By the '60s, he meets a +composer by the name of Deutsch, + +who knew Moog because +of the theremin-- + +his theremin kits-- and +wanted to know about, well, + +if he can do some other types +of synthesizing devices-- + +some other types of +devices that allowed + +you to take basic oscillators, +interconnect them, and put them + +under flexible control. + +Moog develops his first +synthesizer, the 900 Series, + +in 1965. + +This device wasn't +distributed broadly. + +It was used mostly by +composers and some studios. + +In 1966, he patents +his low-pass filter, + +which becomes a very important +part of his synthesizer. + +Because it allowed to take +a rich, wide bandwidth + +sound and control its timbre +and give it a very crisp tone. + +We'll hear some of that +sound very shortly. + +People say that this was the +only thing that Moog patented. + +But there are some other patents +associated with the Moog name. + +It was definitely the first +device that he patented. + +And the low-pass filter +was novel in that it + +had a particularly +steep roll-off curve. + +So it was able to really focus +the sound underneath the cutoff + +frequency. + +And it had an +adjustable resonance, + +which provided a nice peak +at that cutoff frequency. + +Now it's in 1967 +that he releases + +his first real commercial +product, the series Systems 1, + +2, and 3. + +This is an earlier device. + +We can see with this +one, the keyboard. + +We can see some of +the basic modules. + +And we can see, also, a ribbon +controller, another type + +of input device +that he explored. + +This got later +refined into devices + +of this sort, which +is very often what + +we see when we imagine +the Moog synthesizer. + +Here we have a number of +oscillators, filters, up here. + +And this over here +is a sequencer, + +which we're actually going +to talk about sequencing + +next time we meet-- also, +the keyboard and the ribbon + +controller, as well. + +So with the Systems +1, 2, and 3 in 1967, + +there was some standard +packages you could buy. + +But you could still +buy individual modules + +for your own synthesizer. + +And this nice +price list shows us + +some of the prices +of these devices. + +We could get a +voltage-controlled amplifier + +for $150-- fair price. + +That voltage-controlled +low-pass, high-pass filter, + +$475 for one filter in 1968. + +That's pretty expensive. + +These synthesizers were +extremely expensive. + +But they started to be +sold and commercialized. + +And people started to buy them. + +But one thing in particular led +to the explosion of the Moog + +industry, and that was Wendy +Carlos's Switched-on Bach + +recording, recorded in +1968, released in '69, + +and garnered a huge +amount of attention + +to the Moog synthesizer. + +We'll talk about Wendy +Carlos and her recording + +in a little bit. + +But let's review +some of the concepts + +of the modular synthesizer. + +So we have two basic components. + +We have things that +generate sound, + +like our oscillators +and other devices. + +And we have components +that modify those sounds. + +So we have these +two different types + +of modules that can be +interconnected and modified. + +The input four module +is either the knobs + +on the front panel +or another voltage. + +And some devices +allow you to switch + +between using the knob +or a voltage as an input, + +or using both-- using the +knob to set a basic level + +and then the input voltage +to adjust it further. + +The output of these +modules is another voltage, + +which can be interconnected to +modules further down the line. + +Within the modular synthesizer, +we have two types of signals. + +We have control signals +and audio signals. + +Both of these, +depending on the design, + +can be interconnected +in various ways. + +Audio signals are +the things that we're + +used to-- sounds represented +as a bipolar voltage. + +Voltage ranges would generally +between negative 3 and 3 volts. + +Sometimes higher or wider +ranges were possible. + +Control signals were also +voltages but generally unipolar + +voltages between maybe +0 and plus 5 volts. + +These were often +more slowly moving + +signals that could +be used to control + +the parameters of +another module. + +Control signals were used, +obviously, to shape envelopes. + +And these envelopes +could be applied + +to parameters other than +the amplitude of the sound, + +such as a cutoff +frequency or the like. + +Now a key concept of +the modular synthesizer + +was the ability to +reuse the modules. + +We could use an oscillator +to produce a tone + +and hear that tone +of the oscillator. + +We could also use an +oscillator to shape + +the amplitude of a sound +and produce a tremolo, + +or to modulate the frequency +of another oscillator + +and produce a vibrato, or use +the output of an oscillator + +to modulate the cutoff +frequency to create + +a variable timbre to a sound. + +I'm going to demonstrate +all of those in a second. + +This ability to reuse these +modules-- to mix audio signals + +and control signals and +transform one to the other-- + +was really the key feature +of the modular synthesizer, + +combined with voltage +control, and gave it + +a great degree of flexibility. + +Now in this golden age of +the modular synthesizer, + +when you sat down +to this instrument, + +you got nothing for free. + +You sat down. + +It didn't make any sound. + +In order to make a sound, you +had to design an instrument. + +So the interface, in order to +make a sound, became patching. + +You had to patch +to make a sound. + +No sounds were given to you. + +And this promoted a huge degree +of freedom and creativity + +in the design of sounds. + +We see, over the +history of synthesizers, + +this start to decrease. + +And so in the late '60s is +when we have the most freedom. + +And as the '70s move +on, we see synthesizers + +that reduce the +ability of patching + +and make it easier to get +a sound more automatically. + +And then by the early +'80s, we have synthesizers + +that are programmable but +have very little in terms + +of a customizable interface. + +Some of the basic components +of the synthesizer-- these + +are screenshots +of virtual synths, + +which is kind of amusing. + +But they allow us +to see more clearly + +some of the designs +of these synthesizers. + +So our basic oscillators, or +voltage-control oscillators, + +generally provided a +control for frequency. + +Often, the range of +the frequency knob + +would be variable in steps. + +So we have a dedicated +low-frequency switch + +for low-frequency oscillators. + +And then we have +various higher ranges, + +which use the terminology +derived from organs-- + +32 foot, 16 foot, 8 +foot, and the like. + +We had the ability to +get different waveforms + +from the same +oscillator, which is + +a nice convenience +of such devices. + +We have various noise sources, +and we'll hear example of those + +as well. + +And we have a sample on +hold generators, which + +allow us to take an input signal +and sample it periodically + +to create a stepped shape. + +I'll demonstrate that in +a little bit, as well. + +Now our modular +synthesizers usually + +had some sort of mixing +control-- some ability + +to combine signals. + +And this sometimes was under +control of another voltage. + +So we have voltage-control +amplifiers, or VCAs. + +Sometimes we have +mixers that use + +various toggles or +on-off switches. + +This is from the design +of the Minimoog, where + +the various oscillators had +a level control and then + +a toggle switch. + +And some devices +had various types + +of matrix-mixing and +patching controls, + +which are very, very cool. + +This EMS synthesizer-- +the Synthi, + +Synth-I-- allowed you to control +the routing of signals, rather + +than through patch +cords through a matrix. + +This was a template +used to help you + +remember your patch +with this synth. + +These synths are very cool. + +If you can find one, grab it. + +Notice the convenient handle. + +You can take it with you. + +All of our synthesizers have +various types of filters. + +A VCF, or +voltage-control filter, + +allows you to adjust +the parameters + +with a voltage, the low-pass +filter and high-pass filter + +being the most common, +a band-pass filter + +and other varieties also found. + +In our modular synthesizer, +we have various types + +of envelope generators. + +The envelope is +a unipolar signal + +that we can apply to the +amplitude of a sound. + +But we can also +apply the envelope + +to other musical parameters. + +The key thing about an +envelope is its control signal + +that's designed to be triggered. + +It's a control signal +that's designed + +to start at a certain +time and end, as opposed + +to something like a +low-frequency oscillator that + +is continuous and ongoing. + +The ADSR is probably +the most common type + +of envelope control on these +early modular synthesizers, + +although there were +other varieties, as well. + +There was AR filters and +attack-decay-sustain filters-- + +various simplifications +of the ADSR model. + +The key approach to using +the modular synthesizer + +at this time is often called +subtractive synthesis. + +The idea of +subtractive synthesis + +is we start with a +rich, complex tone, + +and we use our filters to +take away from that tone + +and get the sound +that we're looking at. + +This is part of the reason +why Moog's low-pass filter was + +so important. + +Because we could start with +a complex tone and then + +use the low-pass filter to +shape out the frequencies + +that we did not want. + +So our basic approach of +working in subtractive synthesis + +would be to start with +a rich complex tone, + +to cut out some of +those frequencies, + +apply amplitude +envelopes to vary + +the amplitude shape +of that sound, + +and then use modulation +to vary the parameters. + +And this starts to +become really interesting + +when we modulate the modulators. + +And we'll listen to what +that sounds like in a second. + +Questions, comments, ideas? + +OK. + +So let's hear what +this sounds like. + +Now probably the most +basic approach on one + +of the most common approaches +to creating a complex sound + +would be combining +multiple oscillators. + +And this design is embodied +in some of the early Moog + +synthesizers, where we +have three oscillators-- + +like these three oscillators +right here-- all under one + +driver to control the +three oscillators. + +The idea embodied +in the interface + +here is that we're +going to create + +a rich tone by +combining oscillators. + +We can tune each of +these oscillators + +to different octaves and +slight tuning differences. + +But they're all going to +be under a single control. + +Let's listen to what +this sounds like. + +So our first example-- if we +start off with just a single + +oscillator-- + +[LOW-PITCH SYNTHESIZER TONES] + +So here, we're hearing +a sawtooth waveform. + +And I'm taking it +from this oscillator + +here and just dropping it +over into my big ADSR envelope + +there. + +If we want to hear a sign +tone, we can just replace that. + +[SYNTHESIZER] + +That's it. + +A strong sign tone. + +And we have our +triangle waveform here. + +[SYNTHESIZER BEATS] + +Our triangle waveform +sounds dead at that range. + +[SYNTHESIZER BEATS AND TONE] + +That's unexpected. + +Let's go back to this. + +I wonder if I-- + +[SYNTHESIZER] + +There's our saw. + +And then we have our +square wave, which also-- + +[FAINT SYNTHESIZER TONES] + +--is not performing +well, strangely. + +OK. + +So that's our basic oscillators. + +Now we can combine these +to create a rich tone. + +So here, what I've +done is combine + +the sound of three oscillators. + +And let me tune them +all the same first. + +[SYNTHESIZER] + +So we're actually hearing +three oscillators. + +And if you think about what you +think of a Moog sounding like, + +this thick sound is very +much what we think about. + +We're hearing sawtooth +and square waves here + +at different octaves. + +Let me vary the octaves +of this a little bit. + +[SYNTHESIZER] + +Hear that square wave at +the higher octave there? + +[SYNTHESIZER] + +Or if I move up one of +the sawtooth waves-- + +[SYNTHESIZER] + +Or if I set them all +to low registers. + +[LOW-PITCHED SYNTHESIZER TONES] + +Now we can tune each of +these oscillators separately. + +And a very common +practice would be + +to make the oscillators +slightly out of tune + +to create an even thicker sound. + +So if I tune each +of these oscillators + +out a little bit +from the center-- + +[SYNTHESIZER] + +Let me go even further. + +[DISCORDANT SYNTHESIZER TONES] + +Now right there, it sounds +like out-of-tune oscillators. + +But if I bring this +closer together-- + +[WAVERING SYNTHESIZER TONES] + +--we get a thick sound, rather +than an out-of-tune sound. + +Let me shift this one +up an octave or two. + +[SYNTHESIZER] + +And let me set this to be a +little bit more out of tune. + +[WAVERING SYNTHESIZER TONES] + +You don't hear it as +out-of-tune oscillators. + +You hear it as a +single complex tone. + +Now we can see already that most +of these early modular designs + +were designed to be monophonic, +so produce one sound at a time. + +Early on, it was +figured out that it'd + +be pretty nice to +be able to control + +the transition between +these monophonic voices. + +And so we have the use +of a portamento control. + +This was available in the +RCA synthesizer, as well. + +And this would +often set the amount + +of glide between +adjacent pitches. + +So-- + +[SYNTHESIZER] + +Right here, we're hearing +one note at a time. + +If I set the glide-- + +[GLIDING SYNTHESIZER TONES] + +That's a little long there. + +Let me make it a little shorter. + +[CHOPPY SYNTHESIZER TONES] + +A little longer-- + +[GLIDING SYNTHESIZER TONES] + +--which was used very +prominently by musicians-- + +[SYNTHESIZER] + +--to create transitions +between notes, + +and is really one of +the most common sounds + +from these early +monophonic synthesizers. + +Questions? + +AUDIENCE: [INAUDIBLE] +the glide of it? + +Because it seems like +a weird parameter + +to become such a +central thing, or even + +to decide that you need it right +there next to the keyboard. + +It's the thing that you need. + +So was there a reason? + +Obviously there was +a reason for that. + +But was it prominent in music +in a way that [INAUDIBLE]? + +PROFESSOR: Well, I mean, if +a normal musician can control + +this-- for instance, on a guitar +or other string instrument, + +even a lot of wind +instruments, as well. + +And I think the idea was +some musical passages + +you would want to be staccato, +and short, and broken. + +And other cases, +depending on the context, + +you would want to have +that glide control. + +If you want to make it +sound like a theremin, + +you can set it all +the way up, and then + +get continuous pitch variations. + +AUDIENCE: [INAUDIBLE]. + +PROFESSOR: Yeah, exactly. + +AUDIENCE: [LAUGHTER] + +PROFESSOR: OK. + +So our first step in +subtractive synthesis + +is creating a complex tone. + +And we've done that by combining +and de-tuning oscillators. + +We can use a variety of +different wave shapes + +with those oscillators. + +And we can de-tune them. + +And we can add three or-- I +don't know, should we go crazy? + +[SYNTHESIZER] + +If we want to add some +more, let's-- I don't know. + +What does six sound like? + +Let's see. + +Let's throw in a sign tone. + +[SYNTHESIZER] + +That's kind of nice. + +And let's throw in +another sawtooth. + +[SYNTHESIZER] + +[LAUGHS] OK. + +You get the idea. + +So we've produced +our complex tone. + +The next basic step of +subtractive synthesis + +is to apply a filter. + +And this is where Moog's +patented low-pass filter comes + +into play and why his steep +roll-off curve was so valuable. + +We take our complex +tone generated + +by three or more oscillators. + +And we filter it. + +And let's start off +with just the filtered-- + +[SYNTHESIZER] + +OK. + +[SYNTHESIZER] + +We're a little bit ahead +of where we want to be. + +Let's start first +with our complex tone. + +[SYNTHESIZER] + +There's our complex tone. + +And our filter provides +cutoff frequency + +to shape the timbre of that +sound and a resonance control + +to set the amount of amplitude +on the peak of the cutoff + +frequency. + +[HIGH-PITCHED SYNTHESIZER TONES] + +One of the design features +of Moog's low-pass filter + +was that it could self-resonate. + +So if the resonance +was set loud enough-- + +[SYNTHESIZER] + +--we could actually produce +a very clear sinusoidal sound + +at the cutoff frequency. + +[SYNTHESIZER] + +Yeah, you get the idea. + +[SYNTHESIZER] + +So there's our low-pass +filter-- taking our thick tone, + +put it through a +low-pass filter. + +One of the most common +things we want to do + +and one of the easy advantages +of using a modular synthesizer + +is we can take a sign tone, +or some other wave shape, + +and use it to modulate +the cutoff frequency. + +[STATICKY SYNTHESIZER TONES] + +There it's a little fast. + +Let me slow it down. + +[PULSING SYNTHESIZER TONES] + +So now we're modulating +the cutoff frequency + +by a sign tone, whose +frequency I can control-- + +[SLOW WARPED SYNTHESIZER TONES] + +--and whose depth +I can control here. + +We would have to scale it. + +This is much harder to +do with a real synth. + +But this makes it nice and easy. + +[SYNTHESIZER] + +So a very common sound, +using a low-frequency + +oscillator to control +the cutoff frequency. + +Yeah. + +AUDIENCE: Is there a +noticeable difference + +if we modulate the cutoff +of the square or a sawtooth? + +PROFESSOR: Yeah, let's hear it. + +[SYNTHESIZER] + +So yeah, you can +definitely notice it. + +Because here, we're hearing +the smooth transition. + +So let's try a square wave. + +[SYNTHESIZER] + +Right, so we hear +the step pattern. + +If we speed this up, this +is actually pretty cool. + +[SYNTHESIZER TONES WITH BEEPS] + +We get a nice switching. + +And then if we do the-- let's +try a triangle waveform. + +It's not as smooth as a sign. + +We'll get a-- + +[SYNTHESIZER] + +[WARPED SYNTHESIZER TONES] + +There we go. + +So we get a different sound. + +Yeah? + +AUDIENCE: Oh, I just +wanted to clarify + +that all the audio outputs are +also used as control outputs, + +right? + +There's no separation between-- + +PROFESSOR: Different synths +had different designs + +in terms of that. + +AUDIENCE: With the Moog, though. + +PROFESSOR: With +the Moog, well, I + +believe except for the +voltage ranges, sometimes + +you would need to +scale an audio input. + +Some devices, you would need +to transform your voltage + +before you could use it. + +But you could take +an audio oscillator + +and use it as a control +voltage if it could perform + +at a slow enough rate as a +low-frequency oscillator. + +Some designs, you would need +a dedicated low-frequency + +oscillator. + +Because it couldn't perform +slowly in a reliable way. + +That would be an issue +why sometimes there + +would be a dedicated +low-frequency oscillator. + +But with computers, doing +low-frequency oscillation + +is easy. + +So it's more interoperable. + +AUDIENCE: Is there +some responsiveness + +issue with that, where it seems +like you [? couldn't ?] do + +really cool things if you +took audio signal that + +was not synthesized but +recorded, and amplified, + +and made to control things, +like a [INAUDIBLE], kind of. + +PROFESSOR: Absolutely. + +AUDIENCE: Is there a +responsiveness issue? + +Because what you were saying +before about control-voltage + +versus audio signals is +that the control tends + +to be at a slow-- +like obviously, + +audio is at a higher rate, +not [INAUDIBLE] not digital. + +PROFESSOR: Right. + +AUDIENCE: With +that kind of thing, + +is that a problem if you want +to modulate, say, the filter + +with your voice? + +PROFESSOR: Exactly. + +Yeah, I mentioned in passing +that the RCA synthesizer had + +a microphone input. + +And Moog's synthesizers +had-- this one + +doesn't show us a +good example of that-- + +but had microphone inputs. + +We could take an analog +signal, use a low-pass filter + +to smooth out the edges, +and use that to drive + +some other parameters. + +So it was possible +to take other inputs, + +use them to control +your musical parameters. + +That general +technique is something + +we call envelope following. + +And sometimes there would be +dedicated envelope followers + +in these early synths to +make that even easier. + +AUDIENCE: So like optimize +it for that, kind of? + +PROFESSOR: Yeah. + +OK. + +So what we just did was +have our dense combination + +of oscillators. + +And we use an LFO to shape +the sound in a periodic way. + +A very common-- +probably the most common + +approach to +subtractive synthesis-- + +so common that it was embodied +in the design of the Minimoog + +a few years later from the +time of this synthesizer-- + +was using an envelope to +control the cutoff frequency. + +Why would you use an envelope +to control the cutoff frequency? + +So with the LFO, we get +that continuous change + +in the timbre, no matter +when we trigger the note. + +Why would we want to use an +envelope, which we generally + +use to control the +amplitude, to control + +the cutoff frequency +of a filter? + +Any ideas? + +AUDIENCE: More like a +real instrument then, + +if it's linked to when you +play, as opposed to continuous. + +PROFESSOR: That's right. + +Many real instruments +have different timbres + +over the course +of their envelope. + +Many instruments are often +brighter at the initial onset-- + +the articulation-- and then +darken as the tone sustains. + +So a very common approach is to +use a-- pull it up-- envelope. + +And here, I'm using +an ADSR set to trigger + +when I press a note +to control the cutoff + +frequency of the filter. + +And I'll start off with the +modulation of this being small. + +[SYNTHESIZER] + +Here on the onset-- the initial +little bump in the frequency-- + +let me make this broader. + +[SYNTHESIZER] + +And even broader. + +And I'll start off with +the lower start point. + +[SYNTHESIZER TONE BURSTS] + +So that's an extreme setting. + +We're using the ADSR to +control the cutoff frequency. + +[SYNTHESIZER] + +And I can adjust the attack. + +So if the attack is quick, +we'll get a bright sound + +at the very beginning +and then it'll get dark. + +[SYNTHESIZER] + +Ever hear a synthesizer sound +like that before, maybe? + +Probably the most +common approach-- + +subtractive synthesis. + +Use an envelope to +control the cutoff + +frequency of a rich tone. + +If I set the attack +to be longer-- + +[SYNTHESIZER] + +--even longer still-- + +[LONG SYNTHESIZER TONE] + +--we get a very slow increase +in the cutoff frequency. + +And then that was so long, it +didn't even come back down. + +There we go. + +[SYNTHESIZER] + +Good. + +Questions? + +So again, that +approach was so common, + +it was embodied in nearly +almost every synthesizer that + +came after the Moog, +this idea of applying + +a filter to the +cutoff frequencies. + +Some designs, like the Minimoog, +even had a dedicated envelope + +just to control the +cutoff frequency. + +So what else could we do +with the modular synthesizer? + +Well, we could do amplitude +modulation and ring modulation, + +where we modulate the +amplitude of the sound, + +either with a sinusoidal +shape or some other shape. + +And we can use this to +create tremolo effects when + +we use a low-frequency +oscillator + +or amplitude-modulation +or ring-modulation effects + +as we speed up the modulation. + +So in the first +example here, we're + +taking the output of our +three oscillators here, + +and we're putting them +into what is essentially + +a voltage-controlled amplifier. + +And we're modulating the +voltage of the amplifier + +by another oscillator. + +So-- + +[SHORT SYNTHESIZER TONE] + +That was intentional. + +[SYNTHESIZER TONES] + +So this is an +oscillator controlling + +the amplitude of our rich tone. + +As we speed this up-- + +[SYNTHESIZER PULSE TONES] + +--we get a sort +of tremolo sound. + +And as we take this oscillator +into the audio range-- + +this is a great example +of being able to use + +our modules for both audio and +control-rate signals-- we start + +to get some amplitude-modulated + +[SYNTHESIZER] + +--sounds. + +And if I increase +the modulation-- + +[DISTORTED SYNTHESIZER TONES] + +--and again, low frequency. + +[RAPID PULSING SYNTHESIZER + TONES] + +And as before, we can +change the wave shape + +of the amplitude modulation +between our other wave shapes. + +So here, I'm using a sinusoid. + +We could use squares, +or triangles, + +or other shapes, as well. + +Now of course, the next thing to +do is modulate the modulators. + +So if I vary the modulation +of the modulator-- + +[LAUGHS] so here, I'm using +one oscillator to control + +the frequency of another +oscillator that's being used + +to control the amplitude +of our rich tone, + +controlled by +three oscillators-- + +[PULSING SYNTHESIZER TONES] + +--we get a gradual +shift from tremolo + +to amplitude modulation +as I speed this up. + +[SYNTHESIZER] + +Let's see. + +And let's try +something even faster + +and see what that sounds like. + +[PULSING SYNTHESIZER TONES] + +Yeah, we're not hearing +the transition there. + +[SYNTHESIZER] + +And let's try one +more thing and see. + +[SYNTHESIZER] + +So there, we're doing +variable-rate amplitude + +modulation, where the +variance and the rate-- + +[SYNTHESIZER] + +--is determined by +this other oscillator. + +Let's try one more at +this super high speed. + +[RAPID SYNTHESIZER PULSE TONES] + +All right. + +You get the idea. + +Questions? + +So that's amplitude modulation. + +Ring modulation-- +closely related + +to amplitude modulation. + +Sometimes there would +be dedicated devices + +for doing ring modulation. + +On the Moog, there was a +dedicated ring modulator + +that used a special circuit +that was quite popular later. + +Let's just hear a +little bit about how + +that ring motivation +sounds like. + +[WARPED SYNTHESIZER TONES] + +Now here, I'm using an +envelope to modulate + +the frequency of ring +modulation so that we + +get a dynamic contour over +the length of the event-- + +[WARPED SYNTHESIZER TONES] + +--which is kind of fun. + +Good. + +So that's amplitude modulation. + +We can use our oscillators +to control frequency + +and the-- oh yeah, sure. + +AUDIENCE: When you use an +envelope to control the cutoff + +frequency of your +low-pass filter, + +is that still the same +envelope of the output? + +PROFESSOR: I'm using a +different envelope generator. + +So it's like I'm using a +different envelope generator. + +I'm triggering them +at the same time. + +But I'm using a different +ADSR to control that cutoff + +frequency. + +AUDIENCE: OK. + +PROFESSOR: So I'm using +one ADSR to control + +the output envelope +and another ADSR + +to control the cutoff frequency. + +AUDIENCE: OK. + +PROFESSOR: Yeah? + +AUDIENCE: Do key +presses on the keyboard + +trigger all of the whole thing? + +PROFESSOR: It depends on the +design of the synthesizer + +and what's going on. + +For this emulation, +there's an easy way for us + +to set the trigger +for envelopes. + +And you see this +little red light right + +there allows me to +set-- that envelope + +is triggered when +a key press is set. + +There's other ways to +trigger envelopes, as well. + +So vibrato-- our very +basic approach to vibrato + +is done by simply using +one of our oscillators. + +This, of course, is why we +need so many oscillators. + +Because we can use them +for so many things. + +We're using one +of our oscillators + +to modulate the frequency +of our complex tone. + +[WARPED SYNTHESIZER TONES] + +OK. + +Well maybe that doesn't sound +much like a normal vibrato. + +[WARPED SYNTHESIZER TONES] + +So if we reduce the +degree of modulation-- + +[SLOWING WARPED SYNTHESIZER + TONES] + +Let's make it a little slower. + +[SLOWING SYNTHESIZER TONES] + +OK. + +Well, why don't we just +make it really wide? + +[SYNTHESIZER TONES] + +So we can go from something +like a normal vibrato + +to very wide frequency sweeps. + +We still don't +have something that + +sounds like a more +human vibrato. + +Does anybody know why +we don't have something + +that sounds like +a human vibrato? + +Anybody want to speculate? + +It's constant, right? + +The vibrato is constant +the whole time. + +And often, musicians maybe +start off with a straight tone, + +and then lean into the vibrato, +and then stop the vibrato. + +AUDIENCE: And in that +case, you could just + +modulate that modulator to +create that human [INAUDIBLE]. + +PROFESSOR: That's right. + +So we can-- + +AUDIENCE: Envelope on the-- + +AUDIENCE: Right. + +AUDIENCE: Yeah. + +PROFESSOR: That's right. + +We use an envelope to +scale the amplitude + +of the low-frequency +oscillator that's + +driving the +frequency modulation. + +Again, what we do is we +take an ADSR envelope that's + +being triggered when +the note starts. + +And we're putting +that into one of + +our voltage-controlled +amplifiers. + +We're taking the output +of one of our oscillators, + +and scaling the +output by that ADSR, + +and taking the output of +that now modified control + +signal to modulate the frequency +of our rich tone produced + +by three oscillators, +which gives us-- + +[SYNTHESIZER] + +--a vibrato that nicely +fades in and then fades out. + +What determines +the fade-in time? + +Well, it's the attack +of this envelope. + +So if we want it to +come in right away-- + +[SYNTHESIZER] + +--if we want it to +take a long time-- + +[SYNTHESIZER] + +--the depth is set by our +voltage-control amplifier. + +[SYNTHESIZER KNOCKING TONES] + +[LAUGHTER] + +PROFESSOR: OK, maybe I went +a little too far there. + +[WARPED SYNTHESIZER TONES] + +[LAUGHS] OK. + +[LONG SYNTHESIZER TONES AND + TRILLS] + +You get the idea. + +So that's a great example +of using our modules + +for a lot of different things. + +We're using an oscillator to +create variation in frequency. + +We're using one of our envelopes +to scale that variation + +before applying it +to other oscillators. + +Now as we started +to hear there, we + +can push this frequency +modulation even further + +and start to create +new harmonics. + +Frequency modulation, +or FM modulation, + +is when we modulate the +frequency at, or near, + +or beyond the audio +rate, producing + +even more frequencies and +then even more complex timbre. + +Frequency modulation is often +done with assigned tones. + +But we already have a rich tone. + +So what if we just modulate +the frequency of our rich tone + +at the audio rate? + +I'll start with a slow-- + +[SYNTHESIZER] + +You can hear it's already-- +here's low frequency. + +Let me speed it up. + +[SYNTHESIZER] + +And as I increase the +amount of modulation-- + +[VARYING SYNTHESIZER TONES] + +--we get all sorts of +new spectral components + +due to the frequency modulation. + +And of course, we could scale +that frequency modulation. + +We could modulate the modulator. + +So we could control the +parameters of the modulation + +with another oscillator +or another envelope. + +And the process goes on and on. + +Now a very common technique +available as early as the RCA + +synthesizer-- we heard +a little taste of this-- + +was the use of filtered noise. + +We can use our noise sources +through either a low-pass or + +band-pass filter to +create some novel timbres. + +This was used in that +example we listened + +to before to create +a drum sound. + +And it can be used for a +lot of interesting sounds. + +Oh, sorry. + +[SYNTHESIZER] + +That was modulating +the modulator of FM. + +Here's our +filtered-noise example. + +[STATICKY SYNTHESIZER TONES] + +So here I'm using a white-noise +source into a band-pass filter. + +And I'm controlling +the cutoff frequency + +of that band-pass +filter by the keyboard. + +[STATICKY SYNTHESIZER TONES] + +So we can create +something somewhat + +in between a pitched +and unpitched sound. + +[STATICKY AND WARPED SYNTHESIZER + TONES] + +If we try with a +low-pass filter-- + +[SYNTHESIZER TAPS] + +Let's see what this sounds like. + +[VARYING SYNTHESIZER TAPS AND + BEEPS] + +So that's simply noise through +a low-pass filter where + +the cutoff frequency is +controlled by the keyboard, + +which gives us the +ability to create-- + +[SYNTHESIZER BEEPS] + +--some novel sounds. + +Yeah. + +AUDIENCE: What happens +when you modulate + +the modulator with +the audio output? + +[INAUDIBLE] + +Can you even do +that on the Moog? + +PROFESSOR: Yeah. + +On the Moog? + +I'm not sure I +can do it on this. + +But with a computer, we need +to insert a little bit of delay + +in there. + +We'll do that with PD. + +When we work this with +PD, we'll feed that back + +and see what happens. + +You could use +feedback on the Moog, + +particularly with delay, +which is something + +that sometimes people would use. + +Because we still had +the old tape technique. + +So some people would +integrate tape delay + +with the synthesizer, +send a signal out, + +put it through tape +delay, bring it back in, + +which allowed you to do some +pretty interesting things. + +I believe we heard that in the +Oliveros tune, "Alien Bog." + +She used a lot of tape delay. + +The last example I +have for you guys + +is one of the most common sounds +from the modular synthesizer, + +or one of the many +common sounds. + +And this is using +the sample and hold + +generator applied to noise. + +So here, what I'm doing +is taking white noise, + +bringing it into the +sample-and-hold generator. + +The sample and hold takes +that noise and samples + +values from it in +a periodic fashion. + +Here, I'm using the internal +trigger to sample the noise. + +And I'm applying the output +of that to an oscillator + +to do frequency modulation +of the oscillator. + +So in short-- + +[SYNTHESIZER BEEPS] + +--we get this. + +Sound familiar? + +[SYNTHESIZER BEEPS] + +So what we're +doing, again, we're + +taking noise and using it +as a source of randomness. + +But the noise is coming +out at the audio rate. + +So basically, what we need +to do is slow it down. + +And the sample and hold gives +us a way to slow down a signal + +and make it into +a stepped pattern. + +[SYNTHESIZER] + +Here, it's really slow. + +I can speed it up. + +[FASTER SYNTHESIZER TONES] + +And even faster. + +[RAPID SYNTHESIZER TONES] + +And this sample and hold has +a nice glide parameter here, + +which will smooth out the +transition between each step. + +[SYNTHESIZER] + +We spend all our time +gliding, and we don't even + +get to the points. + +[SYNTHESIZER] + +Sample and holds +are a lot of fun. + +Taking noise, putting +it through a sample + +and hold-- a very powerful +way to get random parameters. + +Here, we're hearing +those random parameters + +scaled in a very +wide frequency range. + +We can use it in a much +more narrow range-- + +[SYNTHESIZER] + +--to create more subtle effects. + +Let's see if we can +hear a random vibrato. + +[SYNTHESIZER] + +Oh, I need to scale +this even more. + +[SYNTHESIZER] + +Sort of a random vibrato-- +a very unhuman approach + +and one very idiomatic +to the synthesizer. + +Questions? + +AUDIENCE: The [INAUDIBLE] +is very digital, right? + +PROFESSOR: Well, in a way. + +I mean, the way that +analog-to-digital conversion + +works is essentially through a +process of sampling and holding + +the value. + +But sample and hold processors +were available for a long time. + +AUDIENCE: Yeah. + +But it seems like +an in-between step, + +between this idea of sampling +these individual values out + +and then putting them out. + +It's very digital, kind of. + +PROFESSOR: Yeah, absolutely. + +But then with this +glide control, + +we get right back into +the smooth analog domain. + +So that's-- + +AUDIENCE: It's just like a +A-B-C, B-A-C built together. + +PROFESSOR: Yeah, that's true. + +So-- + +AUDIENCE: I have a question. + +PROFESSOR: Yeah. + +AUDIENCE: So you showed us the +matrix, like the plug-in one. + +Do they have virtual +versions of the matrix? + +Or is it just a bad interface? + +PROFESSOR: Oh, I think +it's a great interface. + +But I don't know of +a virtualized version + +of those EMS synths yet. + +EMS really explore that. + +And there is another +synthesizer-- look + +at this, ARP 2500-- +that use matrices + +for the entire patching system. + +I would love to see a +virtualization of that. + +But I don't know of one yet. + +AUDIENCE: It's sort +of like [INAUDIBLE] + +matrix-based +controls [INAUDIBLE]. + +Does it do-- + +PROFESSOR: Max has a +matrix GUI control. + +Yeah. + +AUDIENCE: So you can [INAUDIBLE] +things and [INAUDIBLE] similar, + +but not-- + +PROFESSOR: Of course, +with this design, + +depending on how +it's implemented, + +you can do one-to-one +connections, + +like with a patch bay. + +But you can also do one-to-many +connections, as long + +as that doesn't weaken +your signal too much. + +Right. + +So we listened to a +number of different pieces + +using the modular +synthesizer-- various sorts. + +Probably some of the +most important in terms + +of the history of +music technology + +were those that were released +on the Switched-on Bach album. + +This was released in +1968 by Wendy Carlos + +and featured this very +unhappy looking guy, well, + +I guess he-- I don't know. + +It's supposed to be Bach. + +He's got headphones. + +And he's sitting in front +of the Moog synthesizer. + +This really solidifies +some of the issues + +in music and technology that +we've seen again and again. + +In order for new instruments +to be successful, + +they often need to be tied +to historical practice. + +And if you want to +legitimize an instrument, + +well, play Bach on it. + +And if you can play Bach on it, +then it's got to be legitimate. + +Quotes of Moog and others +talk about the importance + +of this album in showing people +what this thing was-- what + +the synthesizer was, +that it could be used + +as a musical +instrument and really, + +inspired a whole generation +or generations of musicians + +to become interested +in the Moog. + +They say that sales +of the Moog exploded + +after the release of this album, +at least for a couple of years, + +even though the Moog +was so expensive. + +So I had you guys +listen to two-- refresh + +our memory of these. + +First, "Cantata 147." + +[MUSIC -- JS BACH, "CANTATA + 147"] + +Notice there. + +This is one of my favorite +timbres in this whole album. + +That's a filtered noise +sound you can hear there. + +But it's got a little bit of +modulation on the frequency. + +So it's kind of like there's +a little vibrato on it. + +[MUSIC -- JS BACH, "CANTATA + 147"] + +So there's that, and then +"Well-Tempered Clavier, Book 1, + +Prelude and Fugue in C Minor." + +[MUSIC -- JS BACH, "THE +WELL-TEMPERED CLAVIER, BOOK 1, + +PRELUDE AND FUGUE IN C MINOR"] + +Nice, huh? + +What do you guys think? + +AUDIENCE: I said this +earlier, but that + +was my favorite part +of all the listenings. + +PROFESSOR: Yeah. + +AUDIENCE: They +were very pleasant. + +PROFESSOR: They +were very pleasant. + +I mean, at the time, I +imagine for some people + +they were probably +pretty jarring. + +Some of the timbres in that +are pretty strident timbres. + +But it's still Bach. + +And it relates to +organ sounds that you + +might associate some +of these sounds with. + +Other observations about this? + +AUDIENCE: There was +some volume modulation. + +Was that done independently? + +PROFESSOR: In that right there? + +AUDIENCE: The last one, yeah. + +PROFESSOR: Yeah, you here +it as stepped dynamics. + +And that's because dynamics +was a weak point of the Moog. + +You had a volume control, +but the keyboards + +weren't velocity sensitive. + +So adjusting volume +was difficult. + +So this album was recorded +through multi-track recording. + +So they could do it +in the mixing process + +of recording different +layers or adjusting-- + +AUDIENCE: Yeah, it +seemed a little-- + +PROFESSOR: --the knobs. + +It seems a little +artificial, yeah. + +You hear the step +dynamics there. + +AUDIENCE: So did that +[INAUDIBLE] portable + +synthesizers, the red one with +the keyboard that we looked + +at earlier, have touch-sensitive +keys so the performer could + +actually express dynamics +without having to-- + +PROFESSOR: I'm not sure if +they were just on-off switches + +or if they had some sort of +the more contact the louder, + +or something of the sort. + +That would be +something to look at. + +AUDIENCE: [INAUDIBLE] +ribbon-style controller + +up and down, like they're +higher on key or lower on key. + +I'd notice that. + +But I don't know if +it knows how loud. + +PROFESSOR: Right. + +Yeah. + +We have many devices-- +even Moog explored + +in ribbons-- that would use +a lateral movement for pitch. + +But I'm not sure when we got +a really flexible amplitude + +control into our synths. + +AUDIENCE: Was any +of that sequenced? + +PROFESSOR: It wasn't sequenced. + +It was all performed live. + +But it's a mistake +to think of this + +as just a demonstration +of the Moog synth. + +This composition +was a demonstration + +of the Moog synth and some very +excellent multi-track recording + +and audio production. + +Because this was all +composed and performed + +one part at a time, +recorded to tape, + +and layered one part at a time. + +Remember, the Moog +synth is essentially + +a monophonic instrument +at this time. + +And so she had to play one +part at a time, and layer, + +and re-record, and every +time, adjusting the timbre. + +In many ways, this album-- +I really recommend you guys + +listen to the whole album, +because it's fantastic. + +It's a catalog of sounds you can +make with the Moog synthesizer + +and served as a catalog for +many others afterwards, going, + +what was that sound? + +What was that sound? + +Trying to get the sounds from +that album-- really a resource + +for many other +musicians, I think. + +Other comments about this? + +AUDIENCE: There was a +bit in the reading that + +says that Carlos +commissioned Moog + +to build touch-sensitive +keyboards that + +had velocity control. + +PROFESSOR: Oh, that's great. + +Was it before or after this? + +AUDIENCE: It must've been after. + +PROFESSOR: OK. + +AUDIENCE: I can't +imagine why you'd + +want to [INAUDIBLE] +the volume control. + +PROFESSOR: That's +interesting, yeah. + +She worked with +Moog quite a bit. + +She worked with Moog to +create that Moog demo + +LP, which I sent you +guys the link to. + +She worked with Moog, I think, +to improve the sequencer + +design. + +And that's an interesting issue +about the touch-sensitive, + +volume-sensitive keyboard. + +It'd be interesting to +see when that came in + +and how that was applied. + +So that was a key +point in our history + +of music and technology, +the legitimization + +of the instrument through Bach. + +Now something totally +different comes to us + +from the Netherlands. + +And this is a composition +by Gottfried Michael Koenig, + +a German composer who had +been living and working + +in the Netherlands. + +And he was the artistic +director of a place called + +the Institute of Sonology, +first in Utrecht and now + +in the Hague, where +they had over a period + +of a number of years, developed +their own modular synthesizer + +from scratch. + +So while Moog led to the +first commercial packaged + +synthesizer, many +people were developing + +custom-built synthesizers +that looked something + +like this, where you have +numerous individual components + +often custom designed, +scattered around the room, + +and a giant patch bay to +connect them all together. + +This synthesizer is +still in existence. + +In fact, I took this +photo five years ago. + +This isn't historical. + +It looks like that still. + +And it sounds fantastic. + +It's an amazing-sounding +synthesizer. + +His composition that we +listened to-- "Gray Function," + +is how it translates-- is part +of a series of function pieces + +that explored automating +some of the parameters + +of the modular synthesizer +using a single control + +voltage as a pattern +that was applied + +to numerous different parameters +of a synthesis system. + +We can hear a little bit of +this piece to remind you. + +[MUSIC -- GOTTFRIED MICHAEL + KOENIG, "GRAY FUNCTION"] + +Now this piece was +composed for four channels. + +And the four channels were +composed independently. + +So you can hear that in +this two-channel mix. + +You can hear the four +sources independently moving. + +Thoughts about this piece? + +Is it still going? [LAUGHS] +That was interesting. [LAUGHS] + +What do you think? + +AUDIENCE: I like +the Carlos better. + +But it's interesting. + +PROFESSOR: It's a +little more melodic. + +AUDIENCE: It's +interesting in terms + +of the technical aspect +of how it was created. + +PROFESSOR: Yeah, I think +of this piece providing + +a landscape of noise +textures that we can make. + +Often, we hear these +oscillators combined and used + +for pitch sounds. + +This composition really +gives us a sampling + +of the variety of noise +timbres that could be produced. + +The Institute of +Sonology synthesizer also + +features a number +of modules not found + +on the Moog-- for instance, +voltage-controlled envelope + +generators, so where the +attack, decay, sustain, + +release parameters +could be controlled + +by voltages, which is +pretty interesting. + +So if you think +about that, you could + +set the attack and the +release of a series of sounds + +to be controlled by a +low-frequency oscillator + +or something else, +which allows you + +to create series of +dynamic envelopes. + +So moving on-- Subotnick, +"Silver Apples of the Moon." + +This piece was composed +with a Buchla synthesizer. + +It's not exactly clear how +much multi-track layering + +was going on in the +production of this. + +It's not clear if +this was one set up, + +or if it was multiple +takes of layer. + +That's something to look at +in the production of this. + +This composition +was noted for being + +one of the first recordings +made for commercial distribution + +with a synthesizer. + +It actually predates +Switched-on Bach by a few years + +but didn't have quite +the commercial success + +of Switched-on Bach. + +Let's listen to a +little bit of this. + +[MUSIC -- MORTON SUBOTNICK, + "SILVER APPLES OF THE MOON"] + +Notice the filtered +noise timbres + +coming out of the +speaker right there. + +Notice, also, the-- +say you had a Buchla + +and you wanted to create +that flute-like sound, + +how might you do that? + +Any ideas? + +It sounds to me like an +oscillator with a glide time, + +with its pitch being controlled +by a sample and hold. + +Although we're only getting +a few couple pitches, + +that might be a way that +some of the frequencies + +are chosen in this +composition, using a sample + +and hold adjusted and shifted +to control the frequencies. + +What sort of musical +roles are we hearing? + +Are we hearing +musical roles or parts + +that sound like +acoustic instruments, + +or musical roles +or parts that sound + +like something +totally different? + +I think that's a +useful way for us + +to approach some +of these pieces. + +With the Carlos, +we hear synthesizer + +being used to emulate +parts that were + +done by acoustic instruments. + +In the Koenig +composition, we heard + +sounds that sound nothing +like acoustic instruments. + +With this, we have +a nice mixture + +of sounds that are +somewhat acoustic-sounding + +in their roles and +somewhat electronic. + +Let's listen to a little bit +and think about which is which. + +[MUSIC -- MORTON SUBOTNICK, + "SILVER APPLES OF THE MOON"] + +Well, that was a good +point to do that. + +Because our initial +flute-like sound + +transformed into a something +that a flute player + +couldn't normally do. + +Now in Part B of this, we +get a very surprising change. + +[MUSIC -- MORTON SUBOTNICK, + "SILVER APPLES OF THE MOON"] + +We get this rhythmic section +building up at the end here. + +[MUSIC -- MORTON SUBOTNICK, + "SILVER APPLES OF THE MOON"] + +Now Buchla's early +synthesizers were often notable + +for the use of both +randomness and sequencers. + +So we had various types +of random controllers + +that were pretty novel. + +Your book mentions +that one of them + +was called a Source +of Uncertainty, which + +is a very evocative name +for a random generator, + +and also had +dedicated sequencers. + +We're going to talk about +sequencers next time we meet. + +But we hear there some +use of the sequencer + +to create patterns +of voltages that + +are applied to pitch or +other musical parameters. + +Reflections on this piece? + +Did you like it? + +AUDIENCE: It is long. + +PROFESSOR: It is long. + +AUDIENCE: The first +part, in Part A, + +the noise, I guess, sort of +sounds like the [INAUDIBLE]. + +I think it had like the +[INAUDIBLE] in there. + +PROFESSOR: Right. + +Did you hear accelerating and +de-accelerating articulations? + +AUDIENCE: Sort of. + +Like for real. + +Just the timbre really +matched the usual [INAUDIBLE]. + +[INAUDIBLE] start out +with that one [INAUDIBLE], + +but that timbre's faster. + +PROFESSOR: Yeah, +that's interesting. + +Although that was-- +you sampled here, + +these are all synthesized. + +But yeah, that's +a good connection. + +Anything else? + +I think the depth +of this composition + +is pretty remarkable. + +There's just so much +going on in terms + +of background and +foreground that + +makes it such a +thick composition. + +There had to be +multi-track layering + +going on in this +composition, I think. + +Either that, or they hooked up +numerous synths all together + +in some massive piece. + +All right. + +We had the Oliveros as +well, which is probably + +the one of the most novel +compositions in that it + +doesn't sound at all +like Western instruments + +but really takes advantage +of the synthesizer + +in some unique ways. + +Next time we meet, we're going +to talk about the sequencer + +and continue our trajectory +up to drum machines. + +I'll see you then. + +See you guys. \ No newline at end of file diff --git a/Bv9kVDcj7yo.txt b/Bv9kVDcj7yo.txt new file mode 100644 index 0000000000000000000000000000000000000000..4f2f5b8aa286db98dfec4ba98058c990130f7a4e --- /dev/null +++ b/Bv9kVDcj7yo.txt @@ -0,0 +1,6843 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT open courseware continue + + align:start position:0% +will help MIT open courseware continue + + + align:start position:0% +will help MIT open courseware continue +to offer highquality educational + + align:start position:0% +to offer highquality educational + + + align:start position:0% +to offer highquality educational +resources for free to make a donation or + + align:start position:0% +resources for free to make a donation or + + + align:start position:0% +resources for free to make a donation or +to view additional materials from + + align:start position:0% +to view additional materials from + + + align:start position:0% +to view additional materials from +hundreds of MIT courses visit MIT open + + align:start position:0% +hundreds of MIT courses visit MIT open + + + align:start position:0% +hundreds of MIT courses visit MIT open +courseware at + + align:start position:0% + + + + align:start position:0% + +ocw.mit.edu well um because our subject + + align:start position:0% +ocw.mit.edu well um because our subject + + + align:start position:0% +ocw.mit.edu well um because our subject +today is uh trig integrals and + + align:start position:0% +today is uh trig integrals and + + + align:start position:0% +today is uh trig integrals and +substitutions Professor jarrison called + + align:start position:0% +substitutions Professor jarrison called + + + align:start position:0% +substitutions Professor jarrison called +in his substitute teacher for today + + align:start position:0% +in his substitute teacher for today + + + align:start position:0% +in his substitute teacher for today +that's + + align:start position:0% + + + + align:start position:0% + +me Professor + + align:start position:0% + + + + align:start position:0% + +Miller and I'm going to try to tell you + + align:start position:0% +Miller and I'm going to try to tell you + + + align:start position:0% +Miller and I'm going to try to tell you +about trig trig substitutions and trig + + align:start position:0% +about trig trig substitutions and trig + + + align:start position:0% +about trig trig substitutions and trig +integrals and I'll be here tomorrow to + + align:start position:0% +integrals and I'll be here tomorrow to + + + align:start position:0% +integrals and I'll be here tomorrow to +do more of the same as + + align:start position:0% +do more of the same as + + + align:start position:0% +do more of the same as +well so this is about trigonometry and + + align:start position:0% +well so this is about trigonometry and + + + align:start position:0% +well so this is about trigonometry and +maybe the first thing I'll do is remind + + align:start position:0% +maybe the first thing I'll do is remind + + + align:start position:0% +maybe the first thing I'll do is remind +you of some basic things about + + align:start position:0% + + + + align:start position:0% + +trigonometry so if I have a circle all + + align:start position:0% +trigonometry so if I have a circle all + + + align:start position:0% +trigonometry so if I have a circle all +trigonometry is all based on this circle + + align:start position:0% +trigonometry is all based on this circle + + + align:start position:0% +trigonometry is all based on this circle +of radius one and and centered at the + + align:start position:0% +of radius one and and centered at the + + + align:start position:0% +of radius one and and centered at the +origin and so if this is an angle of + + align:start position:0% +origin and so if this is an angle of + + + align:start position:0% +origin and so if this is an angle of +theta up from the x-axis then the + + align:start position:0% +theta up from the x-axis then the + + + align:start position:0% +theta up from the x-axis then the +coordinates of this point are cosine + + align:start position:0% +coordinates of this point are cosine + + + align:start position:0% +coordinates of this point are cosine +Theta and S + + align:start position:0% +Theta and S + + + align:start position:0% +Theta and S +Theta and so that leads right away to + + align:start position:0% +Theta and so that leads right away to + + + align:start position:0% +Theta and so that leads right away to +some trig identities which you know very + + align:start position:0% +some trig identities which you know very + + + align:start position:0% +some trig identities which you know very +well but I'm going to put them up here U + + align:start position:0% +well but I'm going to put them up here U + + + align:start position:0% +well but I'm going to put them up here U +because we'll use them over and over + + align:start position:0% +because we'll use them over and over + + + align:start position:0% +because we'll use them over and over +again + + align:start position:0% + + + + align:start position:0% + +today remember the convention sin squ of + + align:start position:0% +today remember the convention sin squ of + + + align:start position:0% +today remember the convention sin squ of +theta secretly means s of theta quantity + + align:start position:0% +theta secretly means s of theta quantity + + + align:start position:0% +theta secretly means s of theta quantity +squared it would be more sensible to + + align:start position:0% +squared it would be more sensible to + + + align:start position:0% +squared it would be more sensible to +write a parth is around the sign of + + align:start position:0% +write a parth is around the sign of + + + align:start position:0% +write a parth is around the sign of +theta and then say you square that but + + align:start position:0% +theta and then say you square that but + + + align:start position:0% +theta and then say you square that but +everybody in the world puts the two up + + align:start position:0% +everybody in the world puts the two up + + + align:start position:0% +everybody in the world puts the two up +there over the sign and so I'll do that + + align:start position:0% +there over the sign and so I'll do that + + + align:start position:0% +there over the sign and so I'll do that +too so that follows just because the + + align:start position:0% +too so that follows just because the + + + align:start position:0% +too so that follows just because the +circle has radius one but then there are + + align:start position:0% +circle has radius one but then there are + + + align:start position:0% +circle has radius one but then there are +some other identities too which I think + + align:start position:0% +some other identities too which I think + + + align:start position:0% +some other identities too which I think +you remember I'll write them down here + + align:start position:0% +you remember I'll write them down here + + + align:start position:0% +you remember I'll write them down here +cosine of 2 Theta there's this double + + align:start position:0% +cosine of 2 Theta there's this double + + + align:start position:0% +cosine of 2 Theta there's this double +angle formula that says cosine of 2 + + align:start position:0% +angle formula that says cosine of 2 + + + align:start position:0% +angle formula that says cosine of 2 +Theta is cosine s of + + align:start position:0% +Theta is cosine s of + + + align:start position:0% +Theta is cosine s of +theta minus the sin squ of + + align:start position:0% +theta minus the sin squ of + + + align:start position:0% +theta minus the sin squ of +thet and there's also the double angle + + align:start position:0% +thet and there's also the double angle + + + align:start position:0% +thet and there's also the double angle +formula for the S of 2 Theta uh remember + + align:start position:0% +formula for the S of 2 Theta uh remember + + + align:start position:0% +formula for the S of 2 Theta uh remember +what that + + align:start position:0% + + + + align:start position:0% + +says 2 sin Theta cosine + + align:start position:0% +says 2 sin Theta cosine + + + align:start position:0% +says 2 sin Theta cosine +Theta now um I'm going to use these trig + + align:start position:0% +Theta now um I'm going to use these trig + + + align:start position:0% +Theta now um I'm going to use these trig +identities and I'm going to use them in + + align:start position:0% +identities and I'm going to use them in + + + align:start position:0% +identities and I'm going to use them in +a slightly different way and so I'd like + + align:start position:0% +a slightly different way and so I'd like + + + align:start position:0% +a slightly different way and so I'd like +to pay a little more attention to this + + align:start position:0% +to pay a little more attention to this + + + align:start position:0% +to pay a little more attention to this +one and get some more get a different + + align:start position:0% +one and get some more get a different + + + align:start position:0% +one and get some more get a different +way of writing this one out so this is + + align:start position:0% +way of writing this one out so this is + + + align:start position:0% +way of writing this one out so this is +the actually the half angle formula + + align:start position:0% + + + + align:start position:0% + +and that says uh I'm I'm going to try to + + align:start position:0% +and that says uh I'm I'm going to try to + + + align:start position:0% +and that says uh I'm I'm going to try to +express + + align:start position:0% +express + + + align:start position:0% +express +um the cosine of theta in terms of the + + align:start position:0% +um the cosine of theta in terms of the + + + align:start position:0% +um the cosine of theta in terms of the +cosine of 2 Theta so if I know the + + align:start position:0% +cosine of 2 Theta so if I know the + + + align:start position:0% +cosine of 2 Theta so if I know the +cosine of 2 Theta I want to try to + + align:start position:0% +cosine of 2 Theta I want to try to + + + align:start position:0% +cosine of 2 Theta I want to try to +express the cosine of theta in terms of + + align:start position:0% +express the cosine of theta in terms of + + + align:start position:0% +express the cosine of theta in terms of +it yeah well I'll start with a cosine of + + align:start position:0% +it yeah well I'll start with a cosine of + + + align:start position:0% +it yeah well I'll start with a cosine of +2 Theta and play with that + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +okay well we know what this is It's + + align:start position:0% +okay well we know what this is It's + + + align:start position:0% +okay well we know what this is It's +cosine + + align:start position:0% +cosine + + + align:start position:0% +cosine +2 thet minus the sin s of theta but we + + align:start position:0% +2 thet minus the sin s of theta but we + + + align:start position:0% +2 thet minus the sin s of theta but we +also know what the sin squ of theta is + + align:start position:0% +also know what the sin squ of theta is + + + align:start position:0% +also know what the sin squ of theta is +in terms of the cosine so I can + + align:start position:0% +in terms of the cosine so I can + + + align:start position:0% +in terms of the cosine so I can +eliminate the sin squar from this + + align:start position:0% +eliminate the sin squar from this + + + align:start position:0% +eliminate the sin squar from this +picture so this is equal to the cosine s + + align:start position:0% +picture so this is equal to the cosine s + + + align:start position:0% +picture so this is equal to the cosine s +of theta minus the quantity 1us cosine s + + align:start position:0% +of theta minus the quantity 1us cosine s + + + align:start position:0% +of theta minus the quantity 1us cosine s +of thet I put in what sin squ is in + + align:start position:0% +of thet I put in what sin squ is in + + + align:start position:0% +of thet I put in what sin squ is in +terms of cosine + + align:start position:0% +terms of cosine + + + align:start position:0% +terms of cosine +squ and so that's twice the cosine s of + + align:start position:0% +squ and so that's twice the cosine s of + + + align:start position:0% +squ and so that's twice the cosine s of +theta minus 1 there's this cosine + + align:start position:0% +theta minus 1 there's this cosine + + + align:start position:0% +theta minus 1 there's this cosine +squared which gets a plus sign because + + align:start position:0% +squared which gets a plus sign because + + + align:start position:0% +squared which gets a plus sign because +of these two minus signs and there's the + + align:start position:0% +of these two minus signs and there's the + + + align:start position:0% +of these two minus signs and there's the +one that was there before so altogether + + align:start position:0% +one that was there before so altogether + + + align:start position:0% +one that was there before so altogether +there are two of + + align:start position:0% +there are two of + + + align:start position:0% +there are two of +them I want to isolate what cosine is or + + align:start position:0% +them I want to isolate what cosine is or + + + align:start position:0% +them I want to isolate what cosine is or +rather what cosine squar + + align:start position:0% +rather what cosine squar + + + align:start position:0% +rather what cosine squar +is so let's solve for that so I'll put + + align:start position:0% +is so let's solve for that so I'll put + + + align:start position:0% +is so let's solve for that so I'll put +the one on the other side and I get 1 + + + align:start position:0% +the one on the other side and I get 1 + + + + align:start position:0% +the one on the other side and I get 1 + +cosine of 2 + + align:start position:0% +cosine of 2 + + + align:start position:0% +cosine of 2 +thet and then I want to divide by this + + align:start position:0% +thet and then I want to divide by this + + + align:start position:0% +thet and then I want to divide by this +two and so that puts a two in this + + align:start position:0% +two and so that puts a two in this + + + align:start position:0% +two and so that puts a two in this +denominator here + + align:start position:0% +denominator here + + + align:start position:0% +denominator here +so some people call that the half angle + + align:start position:0% +so some people call that the half angle + + + align:start position:0% +so some people call that the half angle +formula it's a way of what it really is + + align:start position:0% +formula it's a way of what it really is + + + align:start position:0% +formula it's a way of what it really is +for us is it's a way of eliminating + + align:start position:0% +for us is it's a way of eliminating + + + align:start position:0% +for us is it's a way of eliminating +powers from signs and cosin I've gotten + + align:start position:0% +powers from signs and cosin I've gotten + + + align:start position:0% +powers from signs and cosin I've gotten +rid of this square at the expense of + + align:start position:0% +rid of this square at the expense of + + + align:start position:0% +rid of this square at the expense of +putting in a 2 Theta here we'll use that + + align:start position:0% +putting in a 2 Theta here we'll use that + + + align:start position:0% +putting in a 2 Theta here we'll use that +and similarly same calculation shows + + align:start position:0% +and similarly same calculation shows + + + align:start position:0% +and similarly same calculation shows +that the sin squ of theta is 1 minus + + align:start position:0% +that the sin squ of theta is 1 minus + + + align:start position:0% +that the sin squ of theta is 1 minus +cosine of 2 th / two same + + align:start position:0% +cosine of 2 th / two same + + + align:start position:0% +cosine of 2 th / two same +cosine in that formula also but it has a + + align:start position:0% +cosine in that formula also but it has a + + + align:start position:0% +cosine in that formula also but it has a +minus sign for the sin + + align:start position:0% +minus sign for the sin + + + align:start position:0% +minus sign for the sin +squ okay so that's my little review of + + align:start position:0% +squ okay so that's my little review of + + + align:start position:0% +squ okay so that's my little review of +trig identities that we'll make use of + + align:start position:0% +trig identities that we'll make use of + + + align:start position:0% +trig identities that we'll make use of +uh as this this lecture goes + + align:start position:0% +uh as this this lecture goes + + + align:start position:0% +uh as this this lecture goes +on I want to talk about trig identity + + align:start position:0% +on I want to talk about trig identity + + + align:start position:0% +on I want to talk about trig identity +trig integrals and you know some trig + + align:start position:0% +trig integrals and you know some trig + + + align:start position:0% +trig integrals and you know some trig +integrals I'm sure + + align:start position:0% + + + + align:start position:0% + +already uh like well let me write the + + align:start position:0% +already uh like well let me write the + + + align:start position:0% +already uh like well let me write the +differential form first you know that D + + align:start position:0% +differential form first you know that D + + + align:start position:0% +differential form first you know that D +sin Theta or maybe I'll say d + + align:start position:0% + + + + align:start position:0% + +sinx is let's see that's the derivative + + align:start position:0% +sinx is let's see that's the derivative + + + align:start position:0% +sinx is let's see that's the derivative +of sinx * DX right the derivative of + + align:start position:0% +of sinx * DX right the derivative of + + + align:start position:0% +of sinx * DX right the derivative of +sinx is cosine + + align:start position:0% +sinx is cosine + + + align:start position:0% +sinx is cosine +X + + align:start position:0% +X + + + align:start position:0% +X +DX and so if I integrate both sides here + + align:start position:0% +DX and so if I integrate both sides here + + + align:start position:0% +DX and so if I integrate both sides here +the integral form of this is the + + align:start position:0% +the integral form of this is the + + + align:start position:0% +the integral form of this is the +integral of the cosine of x + + align:start position:0% +integral of the cosine of x + + + align:start position:0% +integral of the cosine of x +DX is the S of X plus a constant + + align:start position:0% +DX is the S of X plus a constant + + + align:start position:0% +DX is the S of X plus a constant +and the same way D cosine of x is minus + + align:start position:0% +and the same way D cosine of x is minus + + + align:start position:0% +and the same way D cosine of x is minus +the sin of X DX right the derivative of + + align:start position:0% +the sin of X DX right the derivative of + + + align:start position:0% +the sin of X DX right the derivative of +the cosine is minus the sign and when I + + align:start position:0% +the cosine is minus the sign and when I + + + align:start position:0% +the cosine is minus the sign and when I +integrate that I find the integral of + + align:start position:0% +integrate that I find the integral of + + + align:start position:0% +integrate that I find the integral of +the S of X DX is minus the cosine of x + + align:start position:0% +the S of X DX is minus the cosine of x + + + align:start position:0% +the S of X DX is minus the cosine of x +plus + + align:start position:0% +plus + + + align:start position:0% +plus +C so that's our starting point and the + + align:start position:0% +C so that's our starting point and the + + + align:start position:0% +C so that's our starting point and the +game today uh for the first half of the + + align:start position:0% +game today uh for the first half of the + + + align:start position:0% +game today uh for the first half of the +lecture um is to use uh that base basic + + align:start position:0% +lecture um is to use uh that base basic + + + align:start position:0% +lecture um is to use uh that base basic +those just those basic um integration + + align:start position:0% +those just those basic um integration + + + align:start position:0% +those just those basic um integration +formulas together with clever use of + + align:start position:0% +formulas together with clever use of + + + align:start position:0% +formulas together with clever use of +trig identities in order to compute more + + align:start position:0% +trig identities in order to compute more + + + align:start position:0% +trig identities in order to compute more +complicated formulas involving trig + + align:start position:0% +complicated formulas involving trig + + + align:start position:0% +complicated formulas involving trig +functions so the first + + align:start position:0% +functions so the first + + + align:start position:0% +functions so the first +thing the first uh topic is to think + + align:start position:0% +thing the first uh topic is to think + + + align:start position:0% +thing the first uh topic is to think +about integrals of the form s to the nth + + align:start position:0% +about integrals of the form s to the nth + + + align:start position:0% +about integrals of the form s to the nth +power of x cosine to the nth power of + + align:start position:0% +power of x cosine to the nth power of + + + align:start position:0% +power of x cosine to the nth power of +X DX where here I have in mind m and n + + align:start position:0% +X DX where here I have in mind m and n + + + align:start position:0% +X DX where here I have in mind m and n +are uh posit non- negative + + align:start position:0% +are uh posit non- negative + + + align:start position:0% +are uh posit non- negative +integers so let's try to integrate these + + align:start position:0% +integers so let's try to integrate these + + + align:start position:0% +integers so let's try to integrate these +I'll show you some applications of these + + align:start position:0% +I'll show you some applications of these + + + align:start position:0% +I'll show you some applications of these +pretty soon uh looking down the road a + + align:start position:0% +pretty soon uh looking down the road a + + + align:start position:0% +pretty soon uh looking down the road a +little bit integrals like this show up + + align:start position:0% +little bit integrals like this show up + + + align:start position:0% +little bit integrals like this show up +in fora series and many other uh + + align:start position:0% +in fora series and many other uh + + + align:start position:0% +in fora series and many other uh +subjects in mathematics it turns out + + align:start position:0% +subjects in mathematics it turns out + + + align:start position:0% +subjects in mathematics it turns out +they're quite important to uh be able to + + align:start position:0% +they're quite important to uh be able to + + + align:start position:0% +they're quite important to uh be able to +do so that's why we're doing them + + align:start position:0% +do so that's why we're doing them + + + align:start position:0% +do so that's why we're doing them +now well so um there are two two cases + + align:start position:0% +now well so um there are two two cases + + + align:start position:0% +now well so um there are two two cases +to think about here when you're + + align:start position:0% +to think about here when you're + + + align:start position:0% +to think about here when you're +integrating things like this there's the + + align:start position:0% +integrating things like this there's the + + + align:start position:0% +integrating things like this there's the +easy case and let's do that one first + + align:start position:0% +easy case and let's do that one first + + + align:start position:0% +easy case and let's do that one first +the easy case is + + align:start position:0% +the easy case is + + + align:start position:0% +the easy case is +when at + + align:start position:0% +when at + + + align:start position:0% +when at +least one exponent is + + align:start position:0% + + + + align:start position:0% + +odd that's the easy case so for example + + align:start position:0% +odd that's the easy case so for example + + + align:start position:0% +odd that's the easy case so for example +suppose that I wanted to + + align:start position:0% +suppose that I wanted to + + + align:start position:0% +suppose that I wanted to +integrate uh well let's take the case m + + align:start position:0% +integrate uh well let's take the case m + + + align:start position:0% +integrate uh well let's take the case m +equals 1 + + align:start position:0% + + + + align:start position:0% + +so I'm integrating sin to the N power of + + align:start position:0% +so I'm integrating sin to the N power of + + + align:start position:0% +so I'm integrating sin to the N power of +x * the cosine of x DX I'm taking uh + + align:start position:0% +x * the cosine of x DX I'm taking uh + + + align:start position:0% +x * the cosine of x DX I'm taking uh +oh uh um I could do that one let's see + + align:start position:0% +oh uh um I could do that one let's see + + + align:start position:0% +oh uh um I could do that one let's see +if that's what I want to + + align:start position:0% + + + + align:start position:0% + +take + + align:start position:0% + + + + align:start position:0% + +yeah the my confusion is that I meant to + + align:start position:0% +yeah the my confusion is that I meant to + + + align:start position:0% +yeah the my confusion is that I meant to +have this a different Power you were + + align:start position:0% +have this a different Power you were + + + align:start position:0% +have this a different Power you were +thinking + + align:start position:0% + + + + align:start position:0% + +that so let's do this case when m is one + + align:start position:0% +that so let's do this case when m is one + + + align:start position:0% +that so let's do this case when m is one +so the integral I'm trying to do is any + + align:start position:0% +so the integral I'm trying to do is any + + + align:start position:0% +so the integral I'm trying to do is any +power of the sign times the + + align:start position:0% +power of the sign times the + + + align:start position:0% +power of the sign times the +cosine well um here's the trick uh + + align:start position:0% +cosine well um here's the trick uh + + + align:start position:0% +cosine well um here's the trick uh +recognize use uh this formula up at the + + align:start position:0% +recognize use uh this formula up at the + + + align:start position:0% +recognize use uh this formula up at the +top there to to see cosine of x DX as + + align:start position:0% +top there to to see cosine of x DX as + + + align:start position:0% +top there to to see cosine of x DX as +something that we already have on the + + align:start position:0% +something that we already have on the + + + align:start position:0% +something that we already have on the +Blackboard so the way to to to exploit + + align:start position:0% +Blackboard so the way to to to exploit + + + align:start position:0% +Blackboard so the way to to to exploit +that is to make a substitute + + align:start position:0% + + + + align:start position:0% + +tion and the substitution is going to be + + align:start position:0% +tion and the substitution is going to be + + + align:start position:0% +tion and the substitution is going to be +U is the S of X and here's why then this + + align:start position:0% +U is the S of X and here's why then this + + + align:start position:0% +U is the S of X and here's why then this +integral that I'm trying to do is the + + align:start position:0% +integral that I'm trying to do is the + + + align:start position:0% +integral that I'm trying to do is the +integral of U to the N that's that's + + align:start position:0% +integral of U to the N that's that's + + + align:start position:0% +integral of U to the N that's that's +already a + + align:start position:0% +already a + + + align:start position:0% +already a +simplification and then there's that + + align:start position:0% +simplification and then there's that + + + align:start position:0% +simplification and then there's that +cosine of x * DX when you make a + + align:start position:0% +cosine of x * DX when you make a + + + align:start position:0% +cosine of x * DX when you make a +substitution you've got to go all the + + align:start position:0% +substitution you've got to go all the + + + align:start position:0% +substitution you've got to go all the +way and replace everything in the + + align:start position:0% +way and replace everything in the + + + align:start position:0% +way and replace everything in the +expression by things involved involving + + align:start position:0% +expression by things involved involving + + + align:start position:0% +expression by things involved involving +this new variable that I've introduced + + align:start position:0% +this new variable that I've introduced + + + align:start position:0% +this new variable that I've introduced +so i' better get rid of the cosine of x + + align:start position:0% +so i' better get rid of the cosine of x + + + align:start position:0% +so i' better get rid of the cosine of x +DX and rewrite it in terms of du or in + + align:start position:0% +DX and rewrite it in terms of du or in + + + align:start position:0% +DX and rewrite it in terms of du or in +terms of U and I can do that because + + align:start position:0% +terms of U and I can do that because + + + align:start position:0% +terms of U and I can do that because +du according to that formula is the + + align:start position:0% +du according to that formula is the + + + align:start position:0% +du according to that formula is the +cosine of + + align:start position:0% + + + + align:start position:0% + +x + + align:start position:0% +x + + + align:start position:0% +x +DX let me put a box around that that's + + align:start position:0% +DX let me put a box around that that's + + + align:start position:0% +DX let me put a box around that that's +our substitution when you make a + + align:start position:0% +our substitution when you make a + + + align:start position:0% +our substitution when you make a +substitution you also want to compute + + align:start position:0% +substitution you also want to compute + + + align:start position:0% +substitution you also want to compute +the differential + + align:start position:0% +the differential + + + align:start position:0% +the differential +of the variable that you substitute in + + align:start position:0% +of the variable that you substitute in + + + align:start position:0% +of the variable that you substitute in +so the so the cosine of x DX that + + align:start position:0% +so the so the cosine of x DX that + + + align:start position:0% +so the so the cosine of x DX that +appears here is just exactly du and I've + + align:start position:0% +appears here is just exactly du and I've + + + align:start position:0% +appears here is just exactly du and I've +replaced this trig integral with + + align:start position:0% +replaced this trig integral with + + + align:start position:0% +replaced this trig integral with +something that doesn't involve trig + + align:start position:0% +something that doesn't involve trig + + + align:start position:0% +something that doesn't involve trig +functions at all this is a lot easier we + + align:start position:0% +functions at all this is a lot easier we + + + align:start position:0% +functions at all this is a lot easier we +can just plug into what we know here + + align:start position:0% +can just plug into what we know here + + + align:start position:0% +can just plug into what we know here +this is U to the N +1 Over N + + align:start position:0% +this is U to the N +1 Over N + + + align:start position:0% +this is U to the N +1 Over N ++1 plus a constant and I've done the + + align:start position:0% ++1 plus a constant and I've done the + + + align:start position:0% ++1 plus a constant and I've done the +integral but I'm not quite done with the + + align:start position:0% +integral but I'm not quite done with the + + + align:start position:0% +integral but I'm not quite done with the +problem yet because to be nice to your + + align:start position:0% +problem yet because to be nice to your + + + align:start position:0% +problem yet because to be nice to your +reader and to yourself you should go + + align:start position:0% +reader and to yourself you should go + + + align:start position:0% +reader and to yourself you should go +back at this point probably go back and + + align:start position:0% +back at this point probably go back and + + + align:start position:0% +back at this point probably go back and +get rid of this new variable that you + + align:start position:0% +get rid of this new variable that you + + + align:start position:0% +get rid of this new variable that you +introduced you're the one who introduced + + align:start position:0% +introduced you're the one who introduced + + + align:start position:0% +introduced you're the one who introduced +this variable youu nobody except you + + align:start position:0% +this variable youu nobody except you + + + align:start position:0% +this variable youu nobody except you +really knows what it is right but the + + align:start position:0% +really knows what it is right but the + + + align:start position:0% +really knows what it is right but the +rest of the world knows what they asked + + align:start position:0% +rest of the world knows what they asked + + + align:start position:0% +rest of the world knows what they asked +for in the first place that involved X + + align:start position:0% +for in the first place that involved X + + + align:start position:0% +for in the first place that involved X +so I have to go back and get rid of this + + align:start position:0% +so I have to go back and get rid of this + + + align:start position:0% +so I have to go back and get rid of this +and that's not hard to do in this case + + align:start position:0% +and that's not hard to do in this case + + + align:start position:0% +and that's not hard to do in this case +because U is the sign of X and so I make + + align:start position:0% +because U is the sign of X and so I make + + + align:start position:0% +because U is the sign of X and so I make +this back sub + + align:start position:0% + + + + align:start position:0% + +subtitution and that's what you get so + + align:start position:0% +subtitution and that's what you get so + + + align:start position:0% +subtitution and that's what you get so +there's the + + align:start position:0% + + + + align:start position:0% + +answer okay so the game was I used this + + align:start position:0% +answer okay so the game was I used this + + + align:start position:0% +answer okay so the game was I used this +odd power of of the cosine here and I + + align:start position:0% +odd power of of the cosine here and I + + + align:start position:0% +odd power of of the cosine here and I +could see it appearing as the + + align:start position:0% +could see it appearing as the + + + align:start position:0% +could see it appearing as the +differential of the sign so that's what + + align:start position:0% +differential of the sign so that's what + + + align:start position:0% +differential of the sign so that's what +made this substitution work let's do + + align:start position:0% +made this substitution work let's do + + + align:start position:0% +made this substitution work let's do +another example to see how that works + + align:start position:0% +another example to see how that works + + + align:start position:0% +another example to see how that works +out in a slightly different case + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% + + + + align:start position:0% + +so here's another + + align:start position:0% + + + + align:start position:0% + +example okay now I do have an odd power + + align:start position:0% +example okay now I do have an odd power + + + align:start position:0% +example okay now I do have an odd power +one of the exponents is odd so I'm in + + align:start position:0% +one of the exponents is odd so I'm in + + + align:start position:0% +one of the exponents is odd so I'm in +the e e easy case but it's not one okay + + align:start position:0% +the e e easy case but it's not one okay + + + align:start position:0% +the e e easy case but it's not one okay +the game now is to use uh + + align:start position:0% +the game now is to use uh + + + align:start position:0% +the game now is to use uh +to + + align:start position:0% +to + + + align:start position:0% +to +use uh this this trig + + align:start position:0% +use uh this this trig + + + align:start position:0% +use uh this this trig +identity to get rid of the largest even + + align:start position:0% +identity to get rid of the largest even + + + align:start position:0% +identity to get rid of the largest even +power uh that you can from this odd + + align:start position:0% +power uh that you can from this odd + + + align:start position:0% +power uh that you can from this odd +power here so use uh sin s x is 1us the + + align:start position:0% +power here so use uh sin s x is 1us the + + + align:start position:0% +power here so use uh sin s x is 1us the +cosine s of x to eliminate a lot of + + align:start position:0% +cosine s of x to eliminate a lot of + + + align:start position:0% +cosine s of x to eliminate a lot of +powers from that odd power Watch What + + align:start position:0% +powers from that odd power Watch What + + + align:start position:0% +powers from that odd power Watch What +Happens so this is not + + align:start position:0% +Happens so this is not + + + align:start position:0% +Happens so this is not +really a substitution or anything this + + align:start position:0% +really a substitution or anything this + + + align:start position:0% +really a substitution or anything this +is just a trig + + align:start position:0% +is just a trig + + + align:start position:0% +is just a trig +identity uh this sin cubed is sin squar + + align:start position:0% +identity uh this sin cubed is sin squar + + + align:start position:0% +identity uh this sin cubed is sin squar +time the S and sin squ is 1us the cosine + + align:start position:0% +time the S and sin squ is 1us the cosine + + + align:start position:0% +time the S and sin squ is 1us the cosine +squ of x and then I have the remaining s + + align:start position:0% +squ of x and then I have the remaining s + + + align:start position:0% +squ of x and then I have the remaining s +of X and then I have cosine squ of x + + align:start position:0% + + + + align:start position:0% + +DX so let me rewrite that a little bit + + align:start position:0% +DX so let me rewrite that a little bit + + + align:start position:0% +DX so let me rewrite that a little bit +to see how this works out this is the + + align:start position:0% +to see how this works out this is the + + + align:start position:0% +to see how this works out this is the +integral of uh cosine 2 of x minus + + align:start position:0% +integral of uh cosine 2 of x minus + + + align:start position:0% +integral of uh cosine 2 of x minus +and then there's the product of these + + align:start position:0% +and then there's the product of these + + + align:start position:0% +and then there's the product of these +two that's cosine 4 of X time the S of + + align:start position:0% +two that's cosine 4 of X time the S of + + + align:start position:0% +two that's cosine 4 of X time the S of +X + + align:start position:0% +X + + + align:start position:0% +X +DX so now I'm really exactly in the + + align:start position:0% +DX so now I'm really exactly in the + + + align:start position:0% +DX so now I'm really exactly in the +situation that I was in over here I've + + align:start position:0% +situation that I was in over here I've + + + align:start position:0% +situation that I was in over here I've +got a single power of a of a s or cosine + + align:start position:0% +got a single power of a of a s or cosine + + + align:start position:0% +got a single power of a of a s or cosine +it happens that it's a sign here uh but + + align:start position:0% +it happens that it's a sign here uh but + + + align:start position:0% +it happens that it's a sign here uh but +that's not going to cause any trouble we + + align:start position:0% +that's not going to cause any trouble we + + + align:start position:0% +that's not going to cause any trouble we +can go ahead and play the same same game + + align:start position:0% +can go ahead and play the same same game + + + align:start position:0% +can go ahead and play the same same game +that I did there so so far I've just + + align:start position:0% +that I did there so so far I've just + + + align:start position:0% +that I did there so so far I've just +been using trig identities but now now + + align:start position:0% +been using trig identities but now now + + + align:start position:0% +been using trig identities but now now +I'll use a trigged + + align:start position:0% + + + + align:start position:0% + +substitution and I think I want to write + + align:start position:0% +substitution and I think I want to write + + + align:start position:0% +substitution and I think I want to write +these as powers of a variable and then + + align:start position:0% +these as powers of a variable and then + + + align:start position:0% +these as powers of a variable and then +this is going to be the differential of + + align:start position:0% +this is going to be the differential of + + + align:start position:0% +this is going to be the differential of +that variable so I'll take U to be + + align:start position:0% +that variable so I'll take U to be + + + align:start position:0% +that variable so I'll take U to be +cosine of x and that means that du is + + align:start position:0% +cosine of x and that means that du is + + + align:start position:0% +cosine of x and that means that du is +minus the S of + + align:start position:0% +minus the S of + + + align:start position:0% +minus the S of +X DX there's the substitution + + align:start position:0% + + + + align:start position:0% + +and so when I make that + + align:start position:0% +and so when I make that + + + align:start position:0% +and so when I make that +substitution uh what do we get cosine + + align:start position:0% +substitution uh what do we get cosine + + + align:start position:0% +substitution uh what do we get cosine +squar becomes u^ + + align:start position:0% + + + + align:start position:0% + +2 cosine to 4th becomes U + + align:start position:0% +2 cosine to 4th becomes U + + + align:start position:0% +2 cosine to 4th becomes U +4th and sin of X DX becomes not quite du + + align:start position:0% +4th and sin of X DX becomes not quite du + + + align:start position:0% +4th and sin of X DX becomes not quite du +watch for the Signum watch for this + + align:start position:0% +watch for the Signum watch for this + + + align:start position:0% +watch for the Signum watch for this +minus sign here it becomes minus du + + align:start position:0% + + + + align:start position:0% + +but that's okay the minus sign comes + + align:start position:0% +but that's okay the minus sign comes + + + align:start position:0% +but that's okay the minus sign comes +outside and I can integrate both of + + align:start position:0% +outside and I can integrate both of + + + align:start position:0% +outside and I can integrate both of +these Powers so I get + + align:start position:0% +these Powers so I get + + + align:start position:0% +these Powers so I get +minus U minus U cubed over + + align:start position:0% +minus U minus U cubed over + + + align:start position:0% +minus U minus U cubed over +3 and then this fourth power gives me a + + align:start position:0% +3 and then this fourth power gives me a + + + align:start position:0% +3 and then this fourth power gives me a +fifth power when I + + align:start position:0% +fifth power when I + + + align:start position:0% +fifth power when I +integrate and don't forget the + + align:start position:0% +integrate and don't forget the + + + align:start position:0% +integrate and don't forget the +constant am I done not quite done I have + + align:start position:0% +constant am I done not quite done I have + + + align:start position:0% +constant am I done not quite done I have +to back substitute and get rid of my + + align:start position:0% +to back substitute and get rid of my + + + align:start position:0% +to back substitute and get rid of my +choice of Vari variable U and replace it + + align:start position:0% +choice of Vari variable U and replace it + + + align:start position:0% +choice of Vari variable U and replace it +with yours + + align:start position:0% + + + + align:start position:0% + +questions there should indeed I forgot + + align:start position:0% +questions there should indeed I forgot + + + align:start position:0% +questions there should indeed I forgot +this minus sign when I came down here so + + align:start position:0% +this minus sign when I came down here so + + + align:start position:0% +this minus sign when I came down here so +these two gang up to give me a plus is + + align:start position:0% +these two gang up to give me a plus is + + + align:start position:0% +these two gang up to give me a plus is +that what the other question was about + + align:start position:0% +that what the other question was about + + + align:start position:0% +that what the other question was about +too + + align:start position:0% +too + + + align:start position:0% +too +thanks so let's back substitute and I'm + + align:start position:0% +thanks so let's back substitute and I'm + + + align:start position:0% +thanks so let's back substitute and I'm +going to put that over + + align:start position:0% + + + + align:start position:0% + +here and the result is well I just + + align:start position:0% +here and the result is well I just + + + align:start position:0% +here and the result is well I just +replace the U by cosine of x so this is + + align:start position:0% +replace the U by cosine of x so this is + + + align:start position:0% +replace the U by cosine of x so this is +minus + + align:start position:0% +minus + + + align:start position:0% +minus +cine uh cubed of X over 3 plus thank you + + align:start position:0% +cine uh cubed of X over 3 plus thank you + + + align:start position:0% +cine uh cubed of X over 3 plus thank you +cosine to 5th of X over 5 plus a + + align:start position:0% +cosine to 5th of X over 5 plus a + + + align:start position:0% +cosine to 5th of X over 5 plus a +constant there's the + + align:start position:0% + + + + align:start position:0% + +answer by the way you can remember one + + align:start position:0% +answer by the way you can remember one + + + align:start position:0% +answer by the way you can remember one +of the nice things about doing an + + align:start position:0% +of the nice things about doing an + + + align:start position:0% +of the nice things about doing an +integral is it's fairly easy to check + + align:start position:0% +integral is it's fairly easy to check + + + align:start position:0% +integral is it's fairly easy to check +your answer you can always differentiate + + align:start position:0% +your answer you can always differentiate + + + align:start position:0% +your answer you can always differentiate +the thing you get and see whether it you + + align:start position:0% +the thing you get and see whether it you + + + align:start position:0% +the thing you get and see whether it you +get the right thing when you go back + + align:start position:0% +get the right thing when you go back + + + align:start position:0% +get the right thing when you go back +it's not too hard to use the power rules + + align:start position:0% +it's not too hard to use the power rules + + + align:start position:0% +it's not too hard to use the power rules +and the uh differentiation rule for the + + align:start position:0% +and the uh differentiation rule for the + + + align:start position:0% +and the uh differentiation rule for the +cosine to uh get back to this if you if + + align:start position:0% +cosine to uh get back to this if you if + + + align:start position:0% +cosine to uh get back to this if you if +you want to check the + + align:start position:0% +you want to check the + + + align:start position:0% +you want to check the +work let's do one more example just to + + align:start position:0% +work let's do one more example just to + + + align:start position:0% +work let's do one more example just to +uh take handle a case an example of this + + align:start position:0% +uh take handle a case an example of this + + + align:start position:0% +uh take handle a case an example of this +easy case which you might not have + + align:start position:0% +easy case which you might not have + + + align:start position:0% +easy case which you might not have +thought of at for at first suppose I + + align:start position:0% +thought of at for at first suppose I + + + align:start position:0% +thought of at for at first suppose I +just want to integrate a cube s + + align:start position:0% + + + + align:start position:0% + +cubed of x + + align:start position:0% +cubed of x + + + align:start position:0% +cubed of x +no cosine in + + align:start position:0% +no cosine in + + + align:start position:0% +no cosine in +sight but I do have an odd power of a of + + align:start position:0% +sight but I do have an odd power of a of + + + align:start position:0% +sight but I do have an odd power of a of +a uh trig function of a sign or cosine + + align:start position:0% +a uh trig function of a sign or cosine + + + align:start position:0% +a uh trig function of a sign or cosine +so I'm in the easy case and the um the + + align:start position:0% +so I'm in the easy case and the um the + + + align:start position:0% +so I'm in the easy case and the um the +the procedure that I was suggesting says + + align:start position:0% +the procedure that I was suggesting says + + + align:start position:0% +the procedure that I was suggesting says +I want to take out the largest even + + align:start position:0% +I want to take out the largest even + + + align:start position:0% +I want to take out the largest even +power that I can from the S cubed so + + align:start position:0% +power that I can from the S cubed so + + + align:start position:0% +power that I can from the S cubed so +I'll take that out that's a s squared + + align:start position:0% +I'll take that out that's a s squared + + + align:start position:0% +I'll take that out that's a s squared +and write it as 1 minus cosine + + align:start position:0% + + + + align:start position:0% + +squ well now I'm very happy because it's + + align:start position:0% +squ well now I'm very happy because it's + + + align:start position:0% +squ well now I'm very happy because it's +just like the situation we had + + align:start position:0% +just like the situation we had + + + align:start position:0% +just like the situation we had +um uh somewhere on the board here it's + + align:start position:0% +um uh somewhere on the board here it's + + + align:start position:0% +um uh somewhere on the board here it's +just like the situation we had up here + + align:start position:0% +just like the situation we had up here + + + align:start position:0% +just like the situation we had up here +I've got a power of a cosine time sin of + + align:start position:0% +I've got a power of a cosine time sin of + + + align:start position:0% +I've got a power of a cosine time sin of +X DX so exactly the same substitution + + align:start position:0% +X DX so exactly the same substitution + + + align:start position:0% +X DX so exactly the same substitution +steps + + align:start position:0% +steps + + + align:start position:0% +steps +in you get and and maybe you can see uh + + align:start position:0% +in you get and and maybe you can see uh + + + align:start position:0% +in you get and and maybe you can see uh +what happens without doing doing the + + align:start position:0% +what happens without doing doing the + + + align:start position:0% +what happens without doing doing the +work shall I do the work here I'll make + + align:start position:0% +work shall I do the work here I'll make + + + align:start position:0% +work shall I do the work here I'll make +the same substitution and so this is 1 + + align:start position:0% +the same substitution and so this is 1 + + + align:start position:0% +the same substitution and so this is 1 +minus uh u^2 * minus + + align:start position:0% +minus uh u^2 * minus + + + align:start position:0% +minus uh u^2 * minus +du which + + align:start position:0% +du which + + + align:start position:0% +du which +is U minus U Cub over 3 but then I want + + align:start position:0% +is U minus U Cub over 3 but then I want + + + align:start position:0% +is U minus U Cub over 3 but then I want +to put this minus sign in place and so + + align:start position:0% +to put this minus sign in place and so + + + align:start position:0% +to put this minus sign in place and so +that gives me minus U plus u Cub over3 + + align:start position:0% +that gives me minus U plus u Cub over3 + + + align:start position:0% +that gives me minus U plus u Cub over3 +plus a + + align:start position:0% +plus a + + + align:start position:0% +plus a +constant and then I back substitute and + + align:start position:0% +constant and then I back substitute and + + + align:start position:0% +constant and then I back substitute and +get cosine of x plus cosine Cub of X + + align:start position:0% +get cosine of x plus cosine Cub of X + + + align:start position:0% +get cosine of x plus cosine Cub of X +over + + align:start position:0% + + + + align:start position:0% + +3 so this easy case if you have some odd + + align:start position:0% +3 so this easy case if you have some odd + + + align:start position:0% +3 so this easy case if you have some odd +power to play with then you can make use + + align:start position:0% +power to play with then you can make use + + + align:start position:0% +power to play with then you can make use +of it and uh it's pretty + + align:start position:0% +of it and uh it's pretty + + + align:start position:0% +of it and uh it's pretty +straightforward okay the harder case is + + align:start position:0% +straightforward okay the harder case is + + + align:start position:0% +straightforward okay the harder case is +when you don't have an odd power so + + align:start position:0% +when you don't have an odd power so + + + align:start position:0% +when you don't have an odd power so +what's the program I'm going to do the + + align:start position:0% +what's the program I'm going to do the + + + align:start position:0% +what's the program I'm going to do the +harder case and then I'm going to show + + align:start position:0% +harder case and then I'm going to show + + + align:start position:0% +harder case and then I'm going to show +you an example of how to uh integrate uh + + align:start position:0% +you an example of how to uh integrate uh + + + align:start position:0% +you an example of how to uh integrate uh +square roots uh and do an application + + align:start position:0% +square roots uh and do an application + + + align:start position:0% +square roots uh and do an application +using these ideas from + + align:start position:0% + + + + align:start position:0% + +trigonometry so I want to keep this + + align:start position:0% +trigonometry so I want to keep this + + + align:start position:0% +trigonometry so I want to keep this +black + + align:start position:0% +black + + + align:start position:0% +black +maybe I'll come back and start here + + align:start position:0% + + + + align:start position:0% + +again so the harder + + align:start position:0% + + + + align:start position:0% + +case is when there are only even + + align:start position:0% +case is when there are only even + + + align:start position:0% +case is when there are only even +exponents I'm still trying to integrate + + align:start position:0% +exponents I'm still trying to integrate + + + align:start position:0% +exponents I'm still trying to integrate +the same + + align:start position:0% +the same + + + align:start position:0% +the same +form but now all the exponents are even + + align:start position:0% +form but now all the exponents are even + + + align:start position:0% +form but now all the exponents are even +so we have to do some + + align:start position:0% +so we have to do some + + + align:start position:0% +so we have to do some +game and here the game is use the half + + align:start position:0% +game and here the game is use the half + + + align:start position:0% +game and here the game is use the half +angle + + align:start position:0% + + + + align:start position:0% + +formula which I've just erased very + + align:start position:0% +formula which I've just erased very + + + align:start position:0% +formula which I've just erased very +sadly on the board + + align:start position:0% + + + + align:start position:0% + +here maybe I'll rewrite them over here + + align:start position:0% +here maybe I'll rewrite them over here + + + align:start position:0% +here maybe I'll rewrite them over here +so we have them on the + + align:start position:0% + + + + align:start position:0% + +board I think I remember what they were + + align:start position:0% + + + + align:start position:0% + +okay so the game is I'm going to use + + align:start position:0% +okay so the game is I'm going to use + + + align:start position:0% +okay so the game is I'm going to use +that half angle formula to start getting + + align:start position:0% +that half angle formula to start getting + + + align:start position:0% +that half angle formula to start getting +rid of those even + + align:start position:0% +rid of those even + + + align:start position:0% +rid of those even +Powers half angle formula written like + + align:start position:0% +Powers half angle formula written like + + + align:start position:0% +Powers half angle formula written like +this exactly is going to talks about it + + align:start position:0% +this exactly is going to talks about it + + + align:start position:0% +this exactly is going to talks about it +rewrites even powers of ss and cosines + + align:start position:0% +rewrites even powers of ss and cosines + + + align:start position:0% +rewrites even powers of ss and cosines +so let's see how that works out in an + + align:start position:0% +so let's see how that works out in an + + + align:start position:0% +so let's see how that works out in an +example how about just the cosine squar + + align:start position:0% +example how about just the cosine squar + + + align:start position:0% +example how about just the cosine squar +for for a + + align:start position:0% + + + + align:start position:0% + +start what to do I can't pull pull + + align:start position:0% +start what to do I can't pull pull + + + align:start position:0% +start what to do I can't pull pull +anything out uh I could rewrite this as + + align:start position:0% +anything out uh I could rewrite this as + + + align:start position:0% +anything out uh I could rewrite this as +one minus Co sin squar but then I'd be + + align:start position:0% +one minus Co sin squar but then I'd be + + + align:start position:0% +one minus Co sin squar but then I'd be +faced with integrating the S squar which + + align:start position:0% +faced with integrating the S squar which + + + align:start position:0% +faced with integrating the S squar which +is exactly as hard so instead let's use + + align:start position:0% +is exactly as hard so instead let's use + + + align:start position:0% +is exactly as hard so instead let's use +this formula here this is really the + + align:start position:0% +this formula here this is really the + + + align:start position:0% +this formula here this is really the +same as 1 plus the cosine of 2 Theta / 2 + + align:start position:0% +same as 1 plus the cosine of 2 Theta / 2 + + + align:start position:0% +same as 1 plus the cosine of 2 Theta / 2 +and now um this is + + align:start position:0% +and now um this is + + + align:start position:0% +and now um this is +easy uh it's got two parts to it + + align:start position:0% +easy uh it's got two parts to it + + + align:start position:0% +easy uh it's got two parts to it +integrating 1/2 gives me Theta over + + align:start position:0% +integrating 1/2 gives me Theta over + + + align:start position:0% +integrating 1/2 gives me Theta over +oh miraculously the X turned into a + + align:start position:0% +oh miraculously the X turned into a + + + align:start position:0% +oh miraculously the X turned into a +Theta let's put it back as X I get X + + align:start position:0% +Theta let's put it back as X I get X + + + align:start position:0% +Theta let's put it back as X I get X +over2 by integrating a half so notice + + align:start position:0% +over2 by integrating a half so notice + + + align:start position:0% +over2 by integrating a half so notice +that something non-t trigonometric + + align:start position:0% +that something non-t trigonometric + + + align:start position:0% +that something non-t trigonometric +occurs here when I do these even + + align:start position:0% +occurs here when I do these even + + + align:start position:0% +occurs here when I do these even +integrals X over two + + align:start position:0% +integrals X over two + + + align:start position:0% +integrals X over two +appears and then the other one okay so + + align:start position:0% +appears and then the other one okay so + + + align:start position:0% +appears and then the other one okay so +this takes a little thought the integral + + align:start position:0% +this takes a little thought the integral + + + align:start position:0% +this takes a little thought the integral +of the the cosine is the + + align:start position:0% +of the the cosine is the + + + align:start position:0% +of the the cosine is the +sign or is it minus the sign negative + + align:start position:0% + + + + align:start position:0% + +sign + + align:start position:0% +sign + + + align:start position:0% +sign +okay should we take a vote I think it's + + align:start position:0% +okay should we take a vote I think it's + + + align:start position:0% +okay should we take a vote I think it's +positive so you get the sign of 2x but + + align:start position:0% +positive so you get the sign of 2x but + + + align:start position:0% +positive so you get the sign of 2x but +is that right over two if I + + align:start position:0% +is that right over two if I + + + align:start position:0% +is that right over two if I +differentiate the S of 2x this two comes + + align:start position:0% +differentiate the S of 2x this two comes + + + align:start position:0% +differentiate the S of 2x this two comes +out and would give me an extra two here + + align:start position:0% +out and would give me an extra two here + + + align:start position:0% +out and would give me an extra two here +so it's there's an extra two that I have + + align:start position:0% +so it's there's an extra two that I have + + + align:start position:0% +so it's there's an extra two that I have +to put in here when I integrate + + align:start position:0% + + + + align:start position:0% + +it and there's the + + align:start position:0% +it and there's the + + + align:start position:0% +it and there's the +answer this is not a substitution I just + + align:start position:0% +answer this is not a substitution I just + + + align:start position:0% +answer this is not a substitution I just +played with trig identities here and + + align:start position:0% +played with trig identities here and + + + align:start position:0% +played with trig identities here and +then did a simple uh trig integral + + align:start position:0% +then did a simple uh trig integral + + + align:start position:0% +then did a simple uh trig integral +getting your help to get the sign right + + align:start position:0% +getting your help to get the sign right + + + align:start position:0% +getting your help to get the sign right +and thinking about what this two is + + align:start position:0% +and thinking about what this two is + + + align:start position:0% +and thinking about what this two is +going to do it produces a two in the + + align:start position:0% +going to do it produces a two in the + + + align:start position:0% +going to do it produces a two in the +denominator but it's not applying any + + align:start position:0% +denominator but it's not applying any + + + align:start position:0% +denominator but it's not applying any +um any complicated thing + + align:start position:0% +um any complicated thing + + + align:start position:0% +um any complicated thing +it's just using this + + align:start position:0% +it's just using this + + + align:start position:0% +it's just using this +identity all right let's do another + + align:start position:0% +identity all right let's do another + + + align:start position:0% +identity all right let's do another +example uh that's a little bit harder + + align:start position:0% +example uh that's a little bit harder + + + align:start position:0% +example uh that's a little bit harder +this time s squ time cosine squ + + align:start position:0% + + + + align:start position:0% + +again no odd Powers I've got to work a + + align:start position:0% +again no odd Powers I've got to work a + + + align:start position:0% +again no odd Powers I've got to work a +little bit harder and what I'm going to + + align:start position:0% +little bit harder and what I'm going to + + + align:start position:0% +little bit harder and what I'm going to +do is apply those identities up there + + align:start position:0% +do is apply those identities up there + + + align:start position:0% +do is apply those identities up there +now what I recommend doing in this + + align:start position:0% +now what I recommend doing in this + + + align:start position:0% +now what I recommend doing in this +situation is going over uh to the side + + align:start position:0% +situation is going over uh to the side + + + align:start position:0% +situation is going over uh to the side +somewhere and do some side + + align:start position:0% + + + + align:start position:0% + +work because it's all just playing with + + align:start position:0% +work because it's all just playing with + + + align:start position:0% +work because it's all just playing with +trig function it's not um actually doing + + align:start position:0% +trig function it's not um actually doing + + + align:start position:0% +trig function it's not um actually doing +any integrals for a + + align:start position:0% + + + + align:start position:0% + +while so I guess one way to get rid of + + align:start position:0% +while so I guess one way to get rid of + + + align:start position:0% +while so I guess one way to get rid of +the S squared and the cosine squar is to + + align:start position:0% +the S squared and the cosine squar is to + + + align:start position:0% +the S squared and the cosine squar is to +use those identities and so let's do + + align:start position:0% +use those identities and so let's do + + + align:start position:0% +use those identities and so let's do +that so the S is 1 minus the cosine of + + align:start position:0% +that so the S is 1 minus the cosine of + + + align:start position:0% +that so the S is 1 minus the cosine of +2x over 2 and the cosine is 1 plus the + + align:start position:0% +2x over 2 and the cosine is 1 plus the + + + align:start position:0% +2x over 2 and the cosine is 1 plus the +cosine of 2x over + + align:start position:0% +cosine of 2x over + + + align:start position:0% +cosine of 2x over +2 so I just substitute them in and now I + + align:start position:0% +2 so I just substitute them in and now I + + + align:start position:0% +2 so I just substitute them in and now I +can multiply that out and it's not what + + align:start position:0% +can multiply that out and it's not what + + + align:start position:0% +can multiply that out and it's not what +I have is a a difference times a product + + align:start position:0% +I have is a a difference times a product + + + align:start position:0% +I have is a a difference times a product +sorry difference times a sum so you know + + align:start position:0% +sorry difference times a sum so you know + + + align:start position:0% +sorry difference times a sum so you know +a formula for that um getting taking the + + align:start position:0% +a formula for that um getting taking the + + + align:start position:0% +a formula for that um getting taking the +product of these two things well + + align:start position:0% +product of these two things well + + + align:start position:0% +product of these two things well +there'll be a four in the denominator + + align:start position:0% +there'll be a four in the denominator + + + align:start position:0% +there'll be a four in the denominator +and then in the numerator get I get the + + align:start position:0% +and then in the numerator get I get the + + + align:start position:0% +and then in the numerator get I get the +square of this minus the square of this + + align:start position:0% +square of this minus the square of this + + + align:start position:0% +square of this minus the square of this +right A minus B * a plus b is a^ 2 minus + + align:start position:0% +right A minus B * a plus b is a^ 2 minus + + + align:start position:0% +right A minus B * a plus b is a^ 2 minus +b^ + + align:start position:0% + + + + align:start position:0% + +2 so I get that + + align:start position:0% +2 so I get that + + + align:start position:0% +2 so I get that +well I'm a little bit happier because at + + align:start position:0% +well I'm a little bit happier because at + + + align:start position:0% +well I'm a little bit happier because at +least I don't have four I don't have two + + align:start position:0% +least I don't have four I don't have two + + + align:start position:0% +least I don't have four I don't have two +uh different squares um I still have a + + align:start position:0% +uh different squares um I still have a + + + align:start position:0% +uh different squares um I still have a +square I want to integrate this I'm + + align:start position:0% +square I want to integrate this I'm + + + align:start position:0% +square I want to integrate this I'm +still not in the easy case I got myself + + align:start position:0% +still not in the easy case I got myself + + + align:start position:0% +still not in the easy case I got myself +back to an easier hard + + align:start position:0% +back to an easier hard + + + align:start position:0% +back to an easier hard +case okay but we do know what to do + + align:start position:0% +case okay but we do know what to do + + + align:start position:0% +case okay but we do know what to do +about this because I just did it up + + align:start position:0% +about this because I just did it up + + + align:start position:0% +about this because I just did it up +there um and I could play into this + + align:start position:0% +there um and I could play into this + + + align:start position:0% +there um and I could play into this +formula that we got but I think it's + + align:start position:0% +formula that we got but I think it's + + + align:start position:0% +formula that we got but I think it's +just as easy to start to to continue to + + align:start position:0% +just as easy to start to to continue to + + + align:start position:0% +just as easy to start to to continue to +calculate here use the half angle + + align:start position:0% +calculate here use the half angle + + + align:start position:0% +calculate here use the half angle +formula again for this and continue on + + align:start position:0% +formula again for this and continue on + + + align:start position:0% +formula again for this and continue on +your way so I get a quarter from this + + align:start position:0% +your way so I get a quarter from this + + + align:start position:0% +your way so I get a quarter from this +bit and then minus a + + align:start position:0% +bit and then minus a + + + align:start position:0% +bit and then minus a +quarter of the cosine SAR of 2x okay now + + align:start position:0% +quarter of the cosine SAR of 2x okay now + + + align:start position:0% +quarter of the cosine SAR of 2x okay now +when I plug in 2x in for Theta there in + + align:start position:0% +when I plug in 2x in for Theta there in + + + align:start position:0% +when I plug in 2x in for Theta there in +the top + + align:start position:0% +the top + + + align:start position:0% +the top +board I'm going to get a + + align:start position:0% +board I'm going to get a + + + align:start position:0% +board I'm going to get a +4X on the right hand side + + align:start position:0% + + + + align:start position:0% + +so it comes out like + + align:start position:0% +so it comes out like + + + align:start position:0% +so it comes out like +that and I guess I could simplify that a + + align:start position:0% +that and I guess I could simplify that a + + + align:start position:0% +that and I guess I could simplify that a +little bit more this is a quarter oh but + + align:start position:0% +little bit more this is a quarter oh but + + + align:start position:0% +little bit more this is a quarter oh but +then there's a two here it's half + + align:start position:0% +then there's a two here it's half + + + align:start position:0% +then there's a two here it's half +that so then I can simplify a little + + align:start position:0% +that so then I can simplify a little + + + align:start position:0% +that so then I can simplify a little +more it's a quarter minus an e which is + + align:start position:0% +more it's a quarter minus an e which is + + + align:start position:0% +more it's a quarter minus an e which is +an eighth and then I have uh an eighth + + align:start position:0% +an eighth and then I have uh an eighth + + + align:start position:0% +an eighth and then I have uh an eighth +of + + align:start position:0% +of + + + align:start position:0% +of +cosine of + + align:start position:0% + + + + align:start position:0% + +4X okay that's my side work I just did + + align:start position:0% +4X okay that's my side work I just did + + + align:start position:0% +4X okay that's my side work I just did +some trig identities over here and + + align:start position:0% +some trig identities over here and + + + align:start position:0% +some trig identities over here and +rewrote sin s time cosine squ as + + align:start position:0% +rewrote sin s time cosine squ as + + + align:start position:0% +rewrote sin s time cosine squ as +something which involves just no powers + + align:start position:0% +something which involves just no powers + + + align:start position:0% +something which involves just no powers +of trig just cosine by itself and a and + + align:start position:0% +of trig just cosine by itself and a and + + + align:start position:0% +of trig just cosine by itself and a and +a + + align:start position:0% +a + + + align:start position:0% +a +constant so I can take that and + + align:start position:0% +constant so I can take that and + + + align:start position:0% +constant so I can take that and +substitute it in here and now the + + align:start position:0% +substitute it in here and now the + + + align:start position:0% +substitute it in here and now the +integration is pretty + + align:start position:0% +integration is pretty + + + align:start position:0% +integration is pretty +easy + + align:start position:0% +easy + + + align:start position:0% +easy +1/8 cosine of 4X over + + align:start position:0% +1/8 cosine of 4X over + + + align:start position:0% +1/8 cosine of 4X over +8 DX which is okay the 18 is going to + + align:start position:0% +8 DX which is okay the 18 is going to + + + align:start position:0% +8 DX which is okay the 18 is going to +give me x + + align:start position:0% +give me x + + + align:start position:0% +give me x +8 the integral of cosine is plus or + + align:start position:0% +8 the integral of cosine is plus or + + + align:start position:0% +8 the integral of cosine is plus or +minus the + + align:start position:0% +minus the + + + align:start position:0% +minus the +sign the derivative of the sign is plus + + align:start position:0% +sign the derivative of the sign is plus + + + align:start position:0% +sign the derivative of the sign is plus +the cosine so it's going to be plus the + + align:start position:0% +the cosine so it's going to be plus the + + + align:start position:0% +the cosine so it's going to be plus the +only there's a minus here so it's going + + align:start position:0% +only there's a minus here so it's going + + + align:start position:0% +only there's a minus here so it's going +to be the sign minus the S of 4X divided + + align:start position:0% +to be the sign minus the S of 4X divided + + + align:start position:0% +to be the sign minus the S of 4X divided +by this8 but then I have an additional + + align:start position:0% +by this8 but then I have an additional + + + align:start position:0% +by this8 but then I have an additional +factor in the denominator and what's it + + align:start position:0% +factor in the denominator and what's it + + + align:start position:0% +factor in the denominator and what's it +going to be I have to put a four there + + align:start position:0% + + + + align:start position:0% + +so we've done that calculation + + align:start position:0% +so we've done that calculation + + + align:start position:0% +so we've done that calculation +too so um any of these if you if you + + align:start position:0% +too so um any of these if you if you + + + align:start position:0% +too so um any of these if you if you +keep doing this uh kind of process these + + align:start position:0% +keep doing this uh kind of process these + + + align:start position:0% +keep doing this uh kind of process these +these two kinds of procedures uh any uh + + align:start position:0% +these two kinds of procedures uh any uh + + + align:start position:0% +these two kinds of procedures uh any uh +any you can you you can now integrate + + align:start position:0% +any you can you you can now integrate + + + align:start position:0% +any you can you you can now integrate +any um expression that has a power of a + + align:start position:0% +any um expression that has a power of a + + + align:start position:0% +any um expression that has a power of a +sign times a power of a cosine in it by + + align:start position:0% +sign times a power of a cosine in it by + + + align:start position:0% +sign times a power of a cosine in it by +using these + + align:start position:0% + + + + align:start position:0% + +ideas now let's see + + align:start position:0% + + + + align:start position:0% + +oh Leah let me give you an alternate + + align:start position:0% +oh Leah let me give you an alternate + + + align:start position:0% +oh Leah let me give you an alternate +method for for this last one + + align:start position:0% + + + + align:start position:0% + +here + + align:start position:0% + + + + align:start position:0% + +uh I know what I'll + + align:start position:0% + + + + align:start position:0% + +do let me give an alternate method for + + align:start position:0% +do let me give an alternate method for + + + align:start position:0% +do let me give an alternate method for +doing uh really doing the side work over + + align:start position:0% +doing uh really doing the side work over + + + align:start position:0% +doing uh really doing the side work over +there I'm TR trying to deal with sin s + + align:start position:0% +there I'm TR trying to deal with sin s + + + align:start position:0% +there I'm TR trying to deal with sin s +time cosine squ well that's the + + align:start position:0% + + + + align:start position:0% + +square that's the square of the S of X + + align:start position:0% +square that's the square of the S of X + + + align:start position:0% +square that's the square of the S of X +time the cosine of + + align:start position:0% + + + + align:start position:0% + +x and the S of X time the cosine of x + + align:start position:0% +x and the S of X time the cosine of x + + + align:start position:0% +x and the S of X time the cosine of x +shows up right here in another trig + + align:start position:0% +shows up right here in another trig + + + align:start position:0% +shows up right here in another trig +identity so we can make use of that too + + align:start position:0% +identity so we can make use of that too + + + align:start position:0% +identity so we can make use of that too +um that reduces the number of factors of + + align:start position:0% +um that reduces the number of factors of + + + align:start position:0% +um that reduces the number of factors of +ss and cosiness by one so it's going in + + align:start position:0% +ss and cosiness by one so it's going in + + + align:start position:0% +ss and cosiness by one so it's going in +the right direction this is equal to 12 + + align:start position:0% +the right direction this is equal to 12 + + + align:start position:0% +the right direction this is equal to 12 +s of + + align:start position:0% +s of + + + align:start position:0% +s of +2x squared right s time cosine is a half + + align:start position:0% +2x squared right s time cosine is a half + + + align:start position:0% +2x squared right s time cosine is a half +uh say this + + align:start position:0% +uh say this + + + align:start position:0% +uh say this +right it's s of 2x over two and then I + + align:start position:0% +right it's s of 2x over two and then I + + + align:start position:0% +right it's s of 2x over two and then I +want to square that so what I get is the + + align:start position:0% +want to square that so what I get is the + + + align:start position:0% +want to square that so what I get is the +s^ SAR of + + align:start position:0% +s^ SAR of + + + align:start position:0% +s^ SAR of +2x over 4 + + align:start position:0% + + + + align:start position:0% + +which is well I'm not too happy yet + + align:start position:0% +which is well I'm not too happy yet + + + align:start position:0% +which is well I'm not too happy yet +because I still have an even power + + align:start position:0% +because I still have an even power + + + align:start position:0% +because I still have an even power +remember I'm trying to integrate this + + align:start position:0% +remember I'm trying to integrate this + + + align:start position:0% +remember I'm trying to integrate this +thing in the end even powers are bad I + + align:start position:0% +thing in the end even powers are bad I + + + align:start position:0% +thing in the end even powers are bad I +try to get rid of them by using that um + + align:start position:0% +try to get rid of them by using that um + + + align:start position:0% +try to get rid of them by using that um +formula for the the half angle formula + + align:start position:0% +formula for the the half angle formula + + + align:start position:0% +formula for the the half angle formula +so I can apply that to the S of X here + + align:start position:0% +so I can apply that to the S of X here + + + align:start position:0% +so I can apply that to the S of X here +again I get one quarter of um 1us the + + align:start position:0% +again I get one quarter of um 1us the + + + align:start position:0% +again I get one quarter of um 1us the +cosine of 4X / 2 that's what the half + + align:start position:0% +cosine of 4X / 2 that's what the half + + + align:start position:0% +cosine of 4X / 2 that's what the half +angle formula says for the sin squar of + + align:start position:0% +angle formula says for the sin squar of + + + align:start position:0% +angle formula says for the sin squar of +2x and that's exactly the same as the + + align:start position:0% +2x and that's exactly the same as the + + + align:start position:0% +2x and that's exactly the same as the +expression that I got up here as + + align:start position:0% +expression that I got up here as + + + align:start position:0% +expression that I got up here as +well it's the same expression that I + + align:start position:0% +well it's the same expression that I + + + align:start position:0% +well it's the same expression that I +have + + align:start position:0% +have + + + align:start position:0% +have +there so um it's the same expression as + + align:start position:0% +there so um it's the same expression as + + + align:start position:0% +there so um it's the same expression as +I have here so this is just an alternate + + align:start position:0% +I have here so this is just an alternate + + + align:start position:0% +I have here so this is just an alternate +way to play this game of using the half + + align:start position:0% +way to play this game of using the half + + + align:start position:0% +way to play this game of using the half +angle + + align:start position:0% + + + + align:start position:0% + +formula okay let's do a little + + align:start position:0% +formula okay let's do a little + + + align:start position:0% +formula okay let's do a little +application of these things and uh + + align:start position:0% +application of these things and uh + + + align:start position:0% +application of these things and uh +change the change the topic a little + + align:start position:0% +change the change the topic a little + + + align:start position:0% +change the change the topic a little +[Applause] + + align:start position:0% + + + + align:start position:0% + +bit so here's the problem so this is an + + align:start position:0% + + + + align:start position:0% + +application and + + align:start position:0% +application and + + + align:start position:0% +application and +example of a real tra + + align:start position:0% + + + + align:start position:0% + +substitution so here's the problem I + + align:start position:0% +substitution so here's the problem I + + + align:start position:0% +substitution so here's the problem I +want to look + + align:start position:0% + + + + align:start position:0% + +at okay so I have a circle whose radius + + align:start position:0% +at okay so I have a circle whose radius + + + align:start position:0% +at okay so I have a circle whose radius +is + + align:start position:0% +is + + + align:start position:0% +is +a and I cut out from it um a sort of tab + + align:start position:0% +a and I cut out from it um a sort of tab + + + align:start position:0% +a and I cut out from it um a sort of tab +here this tab + + align:start position:0% + + + + align:start position:0% + +here and the height of this thing is B + + align:start position:0% +here and the height of this thing is B + + + align:start position:0% +here and the height of this thing is B +so this this length is a number B and + + align:start position:0% +so this this length is a number B and + + + align:start position:0% +so this this length is a number B and +what I want to do is compute the area of + + align:start position:0% +what I want to do is compute the area of + + + align:start position:0% +what I want to do is compute the area of +that little + + align:start position:0% +that little + + + align:start position:0% +that little +tab that's the problem so there's an arc + + align:start position:0% +tab that's the problem so there's an arc + + + align:start position:0% +tab that's the problem so there's an arc +over here and that's what I want I want + + align:start position:0% +over here and that's what I want I want + + + align:start position:0% +over here and that's what I want I want +to find the area of this for for A and B + + align:start position:0% +to find the area of this for for A and B + + + align:start position:0% +to find the area of this for for A and B +in terms of of A and B so the + + align:start position:0% + + + + align:start position:0% + +area well um I guess one way to compute + + align:start position:0% +area well um I guess one way to compute + + + align:start position:0% +area well um I guess one way to compute +the area would be to take the integral + + align:start position:0% +the area would be to take the integral + + + align:start position:0% +the area would be to take the integral +of Y + + align:start position:0% +of Y + + + align:start position:0% +of Y +DX I think you've you've seen the idea + + align:start position:0% +DX I think you've you've seen the idea + + + align:start position:0% +DX I think you've you've seen the idea +of splitting this uh up into vertical + + align:start position:0% +of splitting this uh up into vertical + + + align:start position:0% +of splitting this uh up into vertical +strips um whose height is given by a + + align:start position:0% +strips um whose height is given by a + + + align:start position:0% +strips um whose height is given by a +function y of X and then you integrate + + align:start position:0% +function y of X and then you integrate + + + align:start position:0% +function y of X and then you integrate +that that's an interpretation for the + + align:start position:0% +that that's an interpretation for the + + + align:start position:0% +that that's an interpretation for the +integral the area is given by y + + align:start position:0% +integral the area is given by y + + + align:start position:0% +integral the area is given by y +DX but that's a little bit bit awkward + + align:start position:0% +DX but that's a little bit bit awkward + + + align:start position:0% +DX but that's a little bit bit awkward +because my formula for y is going to be + + align:start position:0% +because my formula for y is going to be + + + align:start position:0% +because my formula for y is going to be +a little strange it's constant value of + + align:start position:0% +a little strange it's constant value of + + + align:start position:0% +a little strange it's constant value of +b along here and then at this point it + + align:start position:0% +b along here and then at this point it + + + align:start position:0% +b along here and then at this point it +becomes this Arc of the + + align:start position:0% +becomes this Arc of the + + + align:start position:0% +becomes this Arc of the +circle so working this out I could do it + + align:start position:0% +circle so working this out I could do it + + + align:start position:0% +circle so working this out I could do it +but it's a little awkward because + + align:start position:0% +but it's a little awkward because + + + align:start position:0% +but it's a little awkward because +expressing y as a function of X the top + + align:start position:0% +expressing y as a function of X the top + + + align:start position:0% +expressing y as a function of X the top +edge of this shape it's a little awkward + + align:start position:0% +edge of this shape it's a little awkward + + + align:start position:0% +edge of this shape it's a little awkward +and it takes two different regions to + + align:start position:0% +and it takes two different regions to + + + align:start position:0% +and it takes two different regions to +express so a different way to say it is + + align:start position:0% +express so a different way to say it is + + + align:start position:0% +express so a different way to say it is +to say x Dy + + align:start position:0% +to say x Dy + + + align:start position:0% +to say x Dy +maybe that'll work a little bit better + + align:start position:0% +maybe that'll work a little bit better + + + align:start position:0% +maybe that'll work a little bit better +or maybe it won't but it's worth trying + + align:start position:0% +or maybe it won't but it's worth trying + + + align:start position:0% +or maybe it won't but it's worth trying +I could just as well split this region + + align:start position:0% +I could just as well split this region + + + align:start position:0% +I could just as well split this region +up into horizontal + + align:start position:0% +up into horizontal + + + align:start position:0% +up into horizontal +strips whose width is dy and whose + + align:start position:0% +strips whose width is dy and whose + + + align:start position:0% +strips whose width is dy and whose +length is X now I'm thinking of this as + + align:start position:0% +length is X now I'm thinking of this as + + + align:start position:0% +length is X now I'm thinking of this as +a function of Y this is the graph of a + + align:start position:0% +a function of Y this is the graph of a + + + align:start position:0% +a function of Y this is the graph of a +function of + + align:start position:0% +function of + + + align:start position:0% +function of +Y and that's much better because the + + align:start position:0% +Y and that's much better because the + + + align:start position:0% +Y and that's much better because the +function of Y is well it's the square + + align:start position:0% +function of Y is well it's the square + + + align:start position:0% +function of Y is well it's the square +root of a^2 - y^2 isn't it that's a^2 + + align:start position:0% +root of a^2 - y^2 isn't it that's a^2 + + + align:start position:0% +root of a^2 - y^2 isn't it that's a^2 +plus x^2 + y^2 = + + align:start position:0% +plus x^2 + y^2 = + + + align:start position:0% +plus x^2 + y^2 = +A2 so that's what x + + align:start position:0% + + + + align:start position:0% + +is and that's when I'm asked to + + align:start position:0% +is and that's when I'm asked to + + + align:start position:0% +is and that's when I'm asked to +integrate then the square root of a^2 - + + align:start position:0% +integrate then the square root of a^2 - + + + align:start position:0% +integrate then the square root of a^2 - +y s Dy and I can even put in limits of + + align:start position:0% +y s Dy and I can even put in limits of + + + align:start position:0% +y s Dy and I can even put in limits of +integration maybe I should do that + + align:start position:0% +integration maybe I should do that + + + align:start position:0% +integration maybe I should do that +because this is supposed to be an actual + + align:start position:0% +because this is supposed to be an actual + + + align:start position:0% +because this is supposed to be an actual +number I guess I'm integrating it from + + align:start position:0% +number I guess I'm integrating it from + + + align:start position:0% +number I guess I'm integrating it from +yal Z that's here to yal B Dy + + align:start position:0% + + + + align:start position:0% + +so this is what I want to find this is a + + align:start position:0% +so this is what I want to find this is a + + + align:start position:0% +so this is what I want to find this is a +Formula an integral formula for the area + + align:start position:0% +Formula an integral formula for the area + + + align:start position:0% +Formula an integral formula for the area +of that + + align:start position:0% +of that + + + align:start position:0% +of that +region and this is a new form I don't + + align:start position:0% +region and this is a new form I don't + + + align:start position:0% +region and this is a new form I don't +think that uh that + + align:start position:0% +think that uh that + + + align:start position:0% +think that uh that +you've thought + + align:start position:0% +you've thought + + + align:start position:0% +you've thought +about integrating uh expressions like + + align:start position:0% +about integrating uh expressions like + + + align:start position:0% +about integrating uh expressions like +this uh in this class before so it's a + + align:start position:0% +this uh in this class before so it's a + + + align:start position:0% +this uh in this class before so it's a +new form and I want to show you how to + + align:start position:0% +new form and I want to show you how to + + + align:start position:0% +new form and I want to show you how to +do it how it's related to trigonometry + + align:start position:0% + + + + align:start position:0% + +well it's it's related to trigonometry + + align:start position:0% +well it's it's related to trigonometry + + + align:start position:0% +well it's it's related to trigonometry +through that exact picture that we have + + align:start position:0% +through that exact picture that we have + + + align:start position:0% +through that exact picture that we have +on the + + align:start position:0% +on the + + + align:start position:0% +on the +Blackboard after all this a^2 minus y^2 + + align:start position:0% +Blackboard after all this a^2 minus y^2 + + + align:start position:0% +Blackboard after all this a^2 minus y^2 +is the the formula for this Arc and so + + align:start position:0% +is the the formula for this Arc and so + + + align:start position:0% +is the the formula for this Arc and so +um what I propose is that we try to try + + align:start position:0% +um what I propose is that we try to try + + + align:start position:0% +um what I propose is that we try to try +to exploit the connection with the + + align:start position:0% +to exploit the connection with the + + + align:start position:0% +to exploit the connection with the +circle and introduce polar + + align:start position:0% +circle and introduce polar + + + align:start position:0% +circle and introduce polar +coordinates + + align:start position:0% +coordinates + + + align:start position:0% +coordinates +so here + + align:start position:0% + + + + align:start position:0% + +uh if I take and measure this + + align:start position:0% +uh if I take and measure this + + + align:start position:0% +uh if I take and measure this +angle then there are various things you + + align:start position:0% +angle then there are various things you + + + align:start position:0% +angle then there are various things you +can say like the coordinates of this + + align:start position:0% +can say like the coordinates of this + + + align:start position:0% +can say like the coordinates of this +point here are a cosine Theta a + + align:start position:0% + + + + align:start position:0% + +well I'm sorry it's + + align:start position:0% +well I'm sorry it's + + + align:start position:0% +well I'm sorry it's +not that's an angle but I want to call + + align:start position:0% +not that's an angle but I want to call + + + align:start position:0% +not that's an angle but I want to call +it Theta zero and in general you know + + align:start position:0% +it Theta zero and in general you know + + + align:start position:0% +it Theta zero and in general you know +that the coordinates of this point are a + + align:start position:0% +that the coordinates of this point are a + + + align:start position:0% +that the coordinates of this point are a +cosine Theta a + + align:start position:0% +cosine Theta a + + + align:start position:0% +cosine Theta a +sin Theta if the Ang if the radius is is + + align:start position:0% +sin Theta if the Ang if the radius is is + + + align:start position:0% +sin Theta if the Ang if the radius is is +a and the angle here is + + align:start position:0% +a and the angle here is + + + align:start position:0% +a and the angle here is +Theta so X is cosine of is a cosine + + align:start position:0% +Theta so X is cosine of is a cosine + + + align:start position:0% +Theta so X is cosine of is a cosine +Theta and Y is a sin Theta and just from + + align:start position:0% +Theta and Y is a sin Theta and just from + + + align:start position:0% +Theta and Y is a sin Theta and just from +looking at the geometry of the + + align:start position:0% +looking at the geometry of the + + + align:start position:0% +looking at the geometry of the +circle so let's make that substitution y + + align:start position:0% +circle so let's make that substitution y + + + align:start position:0% +circle so let's make that substitution y +equal a sin + + align:start position:0% + + + + align:start position:0% + +Theta I'm using the the picture to + + align:start position:0% +Theta I'm using the the picture to + + + align:start position:0% +Theta I'm using the the picture to +suggest that maybe making this + + align:start position:0% +suggest that maybe making this + + + align:start position:0% +suggest that maybe making this +substitution is a good thing to do let's + + align:start position:0% +substitution is a good thing to do let's + + + align:start position:0% +substitution is a good thing to do let's +follow along and see what + + align:start position:0% +follow along and see what + + + align:start position:0% +follow along and see what +happens if that's true what we're + + align:start position:0% +happens if that's true what we're + + + align:start position:0% +happens if that's true what we're +interested in is integrating a^2 minus + + align:start position:0% +interested in is integrating a^2 minus + + + align:start position:0% +interested in is integrating a^2 minus +y^2 which is a + + align:start position:0% +y^2 which is a + + + align:start position:0% +y^2 which is a +2 you're interested in integrating the + + align:start position:0% +2 you're interested in integrating the + + + align:start position:0% +2 you're interested in integrating the +square root of a^2 minus y^2 which is + + align:start position:0% +square root of a^2 minus y^2 which is + + + align:start position:0% +square root of a^2 minus y^2 which is +the square root of a^2 minus this a^ 2 + + align:start position:0% +the square root of a^2 minus this a^ 2 + + + align:start position:0% +the square root of a^2 minus this a^ 2 +sin^2 Theta and well that's the square + + align:start position:0% +sin^2 Theta and well that's the square + + + align:start position:0% +sin^2 Theta and well that's the square +root that's equal + + align:start position:0% +root that's equal + + + align:start position:0% +root that's equal +to a * the cosine of theta right that's + + align:start position:0% +to a * the cosine of theta right that's + + + align:start position:0% +to a * the cosine of theta right that's +just a that's just sin s plus cosine squ + + align:start position:0% +just a that's just sin s plus cosine squ + + + align:start position:0% +just a that's just sin s plus cosine squ +equal 1 all over again it's also X this + + align:start position:0% +equal 1 all over again it's also X this + + + align:start position:0% +equal 1 all over again it's also X this +is X and this was X so there a lot of + + align:start position:0% +is X and this was X so there a lot of + + + align:start position:0% +is X and this was X so there a lot of +different ways to think of this but no + + align:start position:0% +different ways to think of this but no + + + align:start position:0% +different ways to think of this but no +matter how you say it the thing we're + + align:start position:0% +matter how you say it the thing we're + + + align:start position:0% +matter how you say it the thing we're +trying to integrate a^2 minus y^2 is in + + align:start position:0% +trying to integrate a^2 minus y^2 is in + + + align:start position:0% +trying to integrate a^2 minus y^2 is in +under this substitution it is a cosine + + align:start position:0% +under this substitution it is a cosine + + + align:start position:0% +under this substitution it is a cosine +of + + align:start position:0% +of + + + align:start position:0% +of +theta so I'm interested in integrating + + align:start position:0% +theta so I'm interested in integrating + + + align:start position:0% +theta so I'm interested in integrating +the square root of a squ - y^2 + + align:start position:0% +the square root of a squ - y^2 + + + align:start position:0% +the square root of a squ - y^2 +Dy and I'm going to make this + + align:start position:0% +Dy and I'm going to make this + + + align:start position:0% +Dy and I'm going to make this +substitution Y is + + align:start position:0% +substitution Y is + + + align:start position:0% +substitution Y is +a Time the S of + + align:start position:0% +a Time the S of + + + align:start position:0% +a Time the S of +theta and so under that + + align:start position:0% +theta and so under that + + + align:start position:0% +theta and so under that +substitution I've decided that theare + + align:start position:0% +substitution I've decided that theare + + + align:start position:0% +substitution I've decided that theare +root of a^ 2us y^2 is a cosine Theta + + align:start position:0% + + + + align:start position:0% + +that's + + align:start position:0% +that's + + + align:start position:0% +that's +this what about the Dy well I better + + align:start position:0% +this what about the Dy well I better + + + align:start position:0% +this what about the Dy well I better +compute the + + align:start position:0% +compute the + + + align:start position:0% +compute the +Dy so Dy just differentiating this + + align:start position:0% +Dy so Dy just differentiating this + + + align:start position:0% +Dy so Dy just differentiating this +expression is a cosine + + align:start position:0% +expression is a cosine + + + align:start position:0% +expression is a cosine +Theta D + + align:start position:0% +Theta D + + + align:start position:0% +Theta D +Theta so let's put that in Dy is a + + align:start position:0% +Theta so let's put that in Dy is a + + + align:start position:0% +Theta so let's put that in Dy is a +cosine Theta D + + align:start position:0% + + + + align:start position:0% + +Theta okay + + align:start position:0% +Theta okay + + + align:start position:0% +Theta okay +making that trig substitution y equal a + + align:start position:0% +making that trig substitution y equal a + + + align:start position:0% +making that trig substitution y equal a +sin Theta has replaced this integral + + align:start position:0% +sin Theta has replaced this integral + + + align:start position:0% +sin Theta has replaced this integral +that has a square root in it and no trig + + align:start position:0% +that has a square root in it and no trig + + + align:start position:0% +that has a square root in it and no trig +functions with an integral that involves + + align:start position:0% +functions with an integral that involves + + + align:start position:0% +functions with an integral that involves +no square roots and only trig + + align:start position:0% +no square roots and only trig + + + align:start position:0% +no square roots and only trig +functions uh in fact it's not too hard + + align:start position:0% +functions uh in fact it's not too hard + + + align:start position:0% +functions uh in fact it's not too hard +to integrate this now because of the + + align:start position:0% +to integrate this now because of the + + + align:start position:0% +to integrate this now because of the +work that we've done the a squ comes out + + align:start position:0% +work that we've done the a squ comes out + + + align:start position:0% +work that we've done the a squ comes out +this is cine 2 + + align:start position:0% +this is cine 2 + + + align:start position:0% +this is cine 2 +Theta D Theta and maybe we've done that + + align:start position:0% +Theta D Theta and maybe we've done that + + + align:start position:0% +Theta D Theta and maybe we've done that +example already today I think we + + align:start position:0% + + + + align:start position:0% + +have uh maybe we can think it through + + align:start position:0% +have uh maybe we can think it through + + + align:start position:0% +have uh maybe we can think it through +but maybe the easiest thing is to look + + align:start position:0% +but maybe the easiest thing is to look + + + align:start position:0% +but maybe the easiest thing is to look +back at notes and see what we got + + align:start position:0% +back at notes and see what we got + + + align:start position:0% +back at notes and see what we got +before that was the first example in the + + align:start position:0% +before that was the first example in the + + + align:start position:0% +before that was the first example in the +hard case that I did and what it came + + align:start position:0% +hard case that I did and what it came + + + align:start position:0% +hard case that I did and what it came +out to I used X instead of theta at the + + align:start position:0% +out to I used X instead of theta at the + + + align:start position:0% +out to I used X instead of theta at the +time + + align:start position:0% + + + + align:start position:0% + +Okay so we've this is a good step + + align:start position:0% +Okay so we've this is a good step + + + align:start position:0% +Okay so we've this is a good step +forward I started with this integral + + align:start position:0% +forward I started with this integral + + + align:start position:0% +forward I started with this integral +that um I really didn't know how to do + + align:start position:0% +that um I really didn't know how to do + + + align:start position:0% +that um I really didn't know how to do +by any uh means that we've had so far + + align:start position:0% +by any uh means that we've had so far + + + align:start position:0% +by any uh means that we've had so far +and I've replaced it by an a trig + + align:start position:0% +and I've replaced it by an a trig + + + align:start position:0% +and I've replaced it by an a trig +integral that we do know how to do and + + align:start position:0% +integral that we do know how to do and + + + align:start position:0% +integral that we do know how to do and +now I've done that trig + + align:start position:0% +now I've done that trig + + + align:start position:0% +now I've done that trig +integral but we're still not quite done + + align:start position:0% +integral but we're still not quite done + + + align:start position:0% +integral but we're still not quite done +because of the problem of back + + align:start position:0% +because of the problem of back + + + align:start position:0% +because of the problem of back +substituting I'd like to go back and + + align:start position:0% +substituting I'd like to go back and + + + align:start position:0% +substituting I'd like to go back and +rewrite this uh in term terms of um of + + align:start position:0% +rewrite this uh in term terms of um of + + + align:start position:0% +rewrite this uh in term terms of um of +the original variable y or I'd like to + + align:start position:0% +the original variable y or I'd like to + + + align:start position:0% +the original variable y or I'd like to +go back and rewrite it in terms of the + + align:start position:0% +go back and rewrite it in terms of the + + + align:start position:0% +go back and rewrite it in terms of the +original limits of integration that we + + align:start position:0% +original limits of integration that we + + + align:start position:0% +original limits of integration that we +had in the original + + align:start position:0% +had in the original + + + align:start position:0% +had in the original +problem in doing that it's going to be + + align:start position:0% +problem in doing that it's going to be + + + align:start position:0% +problem in doing that it's going to be +useful to rewrite this + + align:start position:0% +useful to rewrite this + + + align:start position:0% +useful to rewrite this +expression uh and get rid of the S of 2 + + align:start position:0% +expression uh and get rid of the S of 2 + + + align:start position:0% +expression uh and get rid of the S of 2 +Theta a after all um the original y was + + align:start position:0% +Theta a after all um the original y was + + + align:start position:0% +Theta a after all um the original y was +expressed in terms of the S of theta not + + align:start position:0% +expressed in terms of the S of theta not + + + align:start position:0% +expressed in terms of the S of theta not +the S of 2 Theta so let me just do that + + align:start position:0% +the S of 2 Theta so let me just do that + + + align:start position:0% +the S of 2 Theta so let me just do that +here + + align:start position:0% + + + + align:start position:0% + +um and say that this in turn is equal to + + align:start position:0% +um and say that this in turn is equal to + + + align:start position:0% +um and say that this in turn is equal to +a^ 2 th/ 2 plus well the S of 2 Theta is + + align:start position:0% +a^ 2 th/ 2 plus well the S of 2 Theta is + + + align:start position:0% +a^ 2 th/ 2 plus well the S of 2 Theta is +um twice the S of theta times the cosine + + align:start position:0% +um twice the S of theta times the cosine + + + align:start position:0% +um twice the S of theta times the cosine +of + + align:start position:0% +of + + + align:start position:0% +of +theta and so when there's a four in the + + align:start position:0% +theta and so when there's a four in the + + + align:start position:0% +theta and so when there's a four in the +denominator what I'll get + + align:start position:0% +denominator what I'll get + + + align:start position:0% +denominator what I'll get +is s of theta cosine of theta over two + + align:start position:0% + + + + align:start position:0% + +I did that because I because I'm getting + + align:start position:0% +I did that because I because I'm getting + + + align:start position:0% +I did that because I because I'm getting +closer to the original terms that the + + align:start position:0% +closer to the original terms that the + + + align:start position:0% +closer to the original terms that the +problem uh started with which was s of + + align:start position:0% + + + + align:start position:0% + +theta okay + + align:start position:0% + + + + align:start position:0% + +so let me write down the the the + + align:start position:0% +so let me write down the the the + + + align:start position:0% +so let me write down the the the +integral that we have now the square otk + + align:start position:0% +integral that we have now the square otk + + + align:start position:0% +integral that we have now the square otk +of a^ 2us y^2 Dy is uh so far what we + + align:start position:0% +of a^ 2us y^2 Dy is uh so far what we + + + align:start position:0% +of a^ 2us y^2 Dy is uh so far what we +know is a^2 Theta / 2 + + align:start position:0% +know is a^2 Theta / 2 + + + align:start position:0% +know is a^2 Theta / 2 +plus sin Theta cosine Theta over + + align:start position:0% +plus sin Theta cosine Theta over + + + align:start position:0% +plus sin Theta cosine Theta over +two plus + + align:start position:0% +two plus + + + align:start position:0% +two plus +C but I want to go back and rewrite this + + align:start position:0% +C but I want to go back and rewrite this + + + align:start position:0% +C but I want to go back and rewrite this +in terms of the original value the + + align:start position:0% +in terms of the original value the + + + align:start position:0% +in terms of the original value the +original variable y well what is Theta + + align:start position:0% +original variable y well what is Theta + + + align:start position:0% +original variable y well what is Theta +in terms of + + align:start position:0% + + + + align:start position:0% + +Y let's see Y in terms of theta was + + align:start position:0% +Y let's see Y in terms of theta was + + + align:start position:0% +Y let's see Y in terms of theta was +given like this so what is Theta in + + align:start position:0% +given like this so what is Theta in + + + align:start position:0% +given like this so what is Theta in +terms of Y ah so here the Fearsome arc + + align:start position:0% +terms of Y ah so here the Fearsome arc + + + align:start position:0% +terms of Y ah so here the Fearsome arc +sign rears its head right Theta is the + + align:start position:0% +sign rears its head right Theta is the + + + align:start position:0% +sign rears its head right Theta is the +angle so that y equals a sin of theta so + + align:start position:0% +angle so that y equals a sin of theta so + + + align:start position:0% +angle so that y equals a sin of theta so +that means that Theta is the arc sign or + + align:start position:0% +that means that Theta is the arc sign or + + + align:start position:0% +that means that Theta is the arc sign or +sign inverse of well y / + + align:start position:0% + + + + align:start position:0% + +a so that's what that's the + + align:start position:0% +a so that's what that's the + + + align:start position:0% +a so that's what that's the +first thing that shows up here Ark + + align:start position:0% +first thing that shows up here Ark + + + align:start position:0% +first thing that shows up here Ark +sign of Y over a all over two that's + + align:start position:0% +sign of Y over a all over two that's + + + align:start position:0% +sign of Y over a all over two that's +this term Theta is the ark sign of Y + + align:start position:0% +this term Theta is the ark sign of Y + + + align:start position:0% +this term Theta is the ark sign of Y +over a divided by + + align:start position:0% +over a divided by + + + align:start position:0% +over a divided by +two what about the other side here well + + align:start position:0% +two what about the other side here well + + + align:start position:0% +two what about the other side here well +s and cosine we knew what they were in + + align:start position:0% +s and cosine we knew what they were in + + + align:start position:0% +s and cosine we knew what they were in +terms of Y and in terms of x if you like + + align:start position:0% +terms of Y and in terms of x if you like + + + align:start position:0% +terms of Y and in terms of x if you like +uh s is a + + align:start position:0% +uh s is a + + + align:start position:0% +uh s is a +is actually um maybe I'll put the a squ + + align:start position:0% +is actually um maybe I'll put the a squ + + + align:start position:0% +is actually um maybe I'll put the a squ +inside here that makes a little bit + + align:start position:0% +inside here that makes a little bit + + + align:start position:0% +inside here that makes a little bit +nicer + + align:start position:0% +nicer + + + align:start position:0% +nicer +plus and then the other term is a^ 2 sin + + align:start position:0% +plus and then the other term is a^ 2 sin + + + align:start position:0% +plus and then the other term is a^ 2 sin +of theta cosine of theta so the a * s of + + align:start position:0% +of theta cosine of theta so the a * s of + + + align:start position:0% +of theta cosine of theta so the a * s of +theta is just y maybe I'll write this a + + align:start position:0% +theta is just y maybe I'll write this a + + + align:start position:0% +theta is just y maybe I'll write this a +s of theta a cosine of theta over two + + align:start position:0% +s of theta a cosine of theta over two + + + align:start position:0% +s of theta a cosine of theta over two +plus + + align:start position:0% +plus + + + align:start position:0% +plus +C and so I get the same thing and now + + align:start position:0% +C and so I get the same thing and now + + + align:start position:0% +C and so I get the same thing and now +here a s of theta that's Y and what's + + align:start position:0% +here a s of theta that's Y and what's + + + align:start position:0% +here a s of theta that's Y and what's +the a Time the cosine of + + align:start position:0% +the a Time the cosine of + + + align:start position:0% +the a Time the cosine of +theta it's X or if you like it's the + + align:start position:0% +theta it's X or if you like it's the + + + align:start position:0% +theta it's X or if you like it's the +square root of a a^2 minus y^ + + align:start position:0% + + + + align:start position:0% + +2 and so there I've Rewritten everything + + align:start position:0% + + + + align:start position:0% + +back in terms of the original variable Y + + align:start position:0% +back in terms of the original variable Y + + + align:start position:0% +back in terms of the original variable Y +and there's an + + align:start position:0% + + + + align:start position:0% + +answer so I've done this indefinite + + align:start position:0% +answer so I've done this indefinite + + + align:start position:0% +answer so I've done this indefinite +integration of a of a form in of of this + + align:start position:0% +integration of a of a form in of of this + + + align:start position:0% +integration of a of a form in of of this +quadratic this this uh square root of + + align:start position:0% +quadratic this this uh square root of + + + align:start position:0% +quadratic this this uh square root of +something which is a constant minus y^2 + + align:start position:0% +something which is a constant minus y^2 + + + align:start position:0% +something which is a constant minus y^2 +whenever you see that the thing to think + + align:start position:0% +whenever you see that the thing to think + + + align:start position:0% +whenever you see that the thing to think +of is trigonometry that's going to play + + align:start position:0% +of is trigonometry that's going to play + + + align:start position:0% +of is trigonometry that's going to play +into the sin^2 plus cosine squ identity + + align:start position:0% +into the sin^2 plus cosine squ identity + + + align:start position:0% +into the sin^2 plus cosine squ identity +and the way to exploit it is to make the + + align:start position:0% +and the way to exploit it is to make the + + + align:start position:0% +and the way to exploit it is to make the +substitution y y = a sin of + + align:start position:0% +substitution y y = a sin of + + + align:start position:0% +substitution y y = a sin of +theta you could also make a substitution + + align:start position:0% +theta you could also make a substitution + + + align:start position:0% +theta you could also make a substitution +yal a cosine of theta if you wanted to + + align:start position:0% +yal a cosine of theta if you wanted to + + + align:start position:0% +yal a cosine of theta if you wanted to +and the result would come out to be + + align:start position:0% +and the result would come out to be + + + align:start position:0% +and the result would come out to be +exactly the same in the + + align:start position:0% + + + + align:start position:0% + +end I'm still not quite done with the + + align:start position:0% +end I'm still not quite done with the + + + align:start position:0% +end I'm still not quite done with the +original problem that I + + align:start position:0% +original problem that I + + + align:start position:0% +original problem that I +had + + align:start position:0% +had + + + align:start position:0% +had +because + + align:start position:0% + + + + align:start position:0% + +um because the original problem asked + + align:start position:0% +um because the original problem asked + + + align:start position:0% +um because the original problem asked +for a definite integral so let's just go + + align:start position:0% +for a definite integral so let's just go + + + align:start position:0% +for a definite integral so let's just go +back and finish that as + + align:start position:0% + + + + align:start position:0% + +well so the + + align:start position:0% + + + + align:start position:0% + +area was the integral from 0 to B of + + align:start position:0% +area was the integral from 0 to B of + + + align:start position:0% +area was the integral from 0 to B of +this square + + align:start position:0% + + + + align:start position:0% + +root so I just want to evaluate the + + align:start position:0% +root so I just want to evaluate the + + + align:start position:0% +root so I just want to evaluate the +right hand side here the answer that we + + align:start position:0% +right hand side here the answer that we + + + align:start position:0% +right hand side here the answer that we +came up with this indefinite integral I + + align:start position:0% +came up with this indefinite integral I + + + align:start position:0% +came up with this indefinite integral I +want to evaluate it at zero and at B + + align:start position:0% +want to evaluate it at zero and at B + + + align:start position:0% +want to evaluate it at zero and at B +well let's see when I evaluate it at B I + + align:start position:0% +well let's see when I evaluate it at B I + + + align:start position:0% +well let's see when I evaluate it at B I +get a^2 times the ark + + align:start position:0% +get a^2 times the ark + + + align:start position:0% +get a^2 times the ark +sign + + align:start position:0% +sign + + + align:start position:0% +sign +of + + align:start position:0% +of + + + align:start position:0% +of +of of B over + + align:start position:0% + + + + align:start position:0% + +a over + + align:start position:0% +a over + + + align:start position:0% +a over +two + + align:start position:0% +two + + + align:start position:0% +two +plus uh Y which is + + align:start position:0% +plus uh Y which is + + + align:start position:0% +plus uh Y which is +btimes the sare < TK of a^ 2 minus b^2 + + align:start position:0% +btimes the sare < TK of a^ 2 minus b^2 + + + align:start position:0% +btimes the sare < TK of a^ 2 minus b^2 +putting y equal to B divided by + + align:start position:0% +putting y equal to B divided by + + + align:start position:0% +putting y equal to B divided by +two so I've plugged in yals B into that + + align:start position:0% +two so I've plugged in yals B into that + + + align:start position:0% +two so I've plugged in yals B into that +formula this is what I get then when I + + align:start position:0% +formula this is what I get then when I + + + align:start position:0% +formula this is what I get then when I +plug in y equals 0 well the sign of 0 is + + align:start position:0% +plug in y equals 0 well the sign of 0 is + + + align:start position:0% +plug in y equals 0 well the sign of 0 is +0 so the arc sign of 0 is 0o so this + + align:start position:0% +0 so the arc sign of 0 is 0o so this + + + align:start position:0% +0 so the arc sign of 0 is 0o so this +term goes away and when Y is equal to + + align:start position:0% +term goes away and when Y is equal to + + + align:start position:0% +term goes away and when Y is equal to +zero this term is zero also and so I + + align:start position:0% +zero this term is zero also and so I + + + align:start position:0% +zero this term is zero also and so I +don't get any subtracted terms at all so + + align:start position:0% +don't get any subtracted terms at all so + + + align:start position:0% +don't get any subtracted terms at all so +there's an expression for this notice + + align:start position:0% +there's an expression for this notice + + + align:start position:0% +there's an expression for this notice +that this Ark sign of B over + + align:start position:0% +that this Ark sign of B over + + + align:start position:0% +that this Ark sign of B over +a that's exactly this angle the ark sign + + align:start position:0% +a that's exactly this angle the ark sign + + + align:start position:0% +a that's exactly this angle the ark sign +of B over a uh it's the angle that that + + align:start position:0% +of B over a uh it's the angle that that + + + align:start position:0% +of B over a uh it's the angle that that +you get when y equals B so this Theta is + + align:start position:0% +you get when y equals B so this Theta is + + + align:start position:0% +you get when y equals B so this Theta is +the AR + + align:start position:0% +the AR + + + align:start position:0% +the AR +sign of B over + + align:start position:0% + + + + align:start position:0% + +a put this over + + align:start position:0% + + + + align:start position:0% + +here that is Theta 0 that is the angle + + align:start position:0% +here that is Theta 0 that is the angle + + + align:start position:0% +here that is Theta 0 that is the angle +that the corner + + align:start position:0% +that the corner + + + align:start position:0% +that the corner +makes so I could rewrite this as a^ 2 + + align:start position:0% +makes so I could rewrite this as a^ 2 + + + align:start position:0% +makes so I could rewrite this as a^ 2 +Theta 0 / 2 + B * the < TK of a^ 2 - b^ + + align:start position:0% +Theta 0 / 2 + B * the < TK of a^ 2 - b^ + + + align:start position:0% +Theta 0 / 2 + B * the < TK of a^ 2 - b^ +2 over + + align:start position:0% + + + + align:start position:0% + +2 let's just think about this for a + + align:start position:0% +2 let's just think about this for a + + + align:start position:0% +2 let's just think about this for a +minute I have these two terms in the sum + + align:start position:0% +minute I have these two terms in the sum + + + align:start position:0% +minute I have these two terms in the sum +is that reasonable the first term is a s + + align:start position:0% +is that reasonable the first term is a s + + + align:start position:0% +is that reasonable the first term is a s +that's the radius squar times this angle + + align:start position:0% +that's the radius squar times this angle + + + align:start position:0% +that's the radius squar times this angle +times a + + align:start position:0% +times a + + + align:start position:0% +times a +half well I think that is exactly the + + align:start position:0% +half well I think that is exactly the + + + align:start position:0% +half well I think that is exactly the +area of this sector a^2 thet / 2 is the + + align:start position:0% +area of this sector a^2 thet / 2 is the + + + align:start position:0% +area of this sector a^2 thet / 2 is the +formula for the area of the + + align:start position:0% + + + + align:start position:0% + +sector and this one this is the vertical + + align:start position:0% +sector and this one this is the vertical + + + align:start position:0% +sector and this one this is the vertical +elevation this is the horizontal B a^2 + + align:start position:0% +elevation this is the horizontal B a^2 + + + align:start position:0% +elevation this is the horizontal B a^2 +minus b^2 is this + + align:start position:0% +minus b^2 is this + + + align:start position:0% +minus b^2 is this +distance square root of a^ 2us b^ 2 so + + align:start position:0% +distance square root of a^ 2us b^ 2 so + + + align:start position:0% +distance square root of a^ 2us b^ 2 so +the right hand term is B time theun of + + align:start position:0% +the right hand term is B time theun of + + + align:start position:0% +the right hand term is B time theun of +a^ 2us b s divided two that's the area + + align:start position:0% +a^ 2us b s divided two that's the area + + + align:start position:0% +a^ 2us b s divided two that's the area +of that triangle + + align:start position:0% + + + + align:start position:0% + +so using a little bit of geometry gives + + align:start position:0% +so using a little bit of geometry gives + + + align:start position:0% +so using a little bit of geometry gives +you the same answer as all of this + + align:start position:0% +you the same answer as all of this + + + align:start position:0% +you the same answer as all of this +elaborate calculus uh uh maybe that's + + align:start position:0% +elaborate calculus uh uh maybe that's + + + align:start position:0% +elaborate calculus uh uh maybe that's +enough cause for celebration for us to + + align:start position:0% +enough cause for celebration for us to + + + align:start position:0% +enough cause for celebration for us to +quit for today \ No newline at end of file diff --git a/CD_HqiEdNOw.txt b/CD_HqiEdNOw.txt new file mode 100644 index 0000000000000000000000000000000000000000..1f4de5fa2bf8d97431dd444b457bed22939be849 --- /dev/null +++ b/CD_HqiEdNOw.txt @@ -0,0 +1,8947 @@ +align:start position:0% + +so today we are going to move on to a + + align:start position:0% +so today we are going to move on to a + + + align:start position:0% +so today we are going to move on to a +new topic once again to remind you where + + align:start position:0% +new topic once again to remind you where + + + align:start position:0% +new topic once again to remind you where +of of the path of how we got here in + + align:start position:0% +of of the path of how we got here in + + + align:start position:0% +of of the path of how we got here in +within producer Theory we said that it's + + align:start position:0% +within producer Theory we said that it's + + + align:start position:0% +within producer Theory we said that it's +harder than consumer Theory because you + + align:start position:0% +harder than consumer Theory because you + + + align:start position:0% +harder than consumer Theory because you +don't only do the standard optimization + + align:start position:0% +don't only do the standard optimization + + + align:start position:0% +don't only do the standard optimization +the consumer Theory but you need a third + + align:start position:0% +the consumer Theory but you need a third + + + align:start position:0% +the consumer Theory but you need a third +condition you need a market structure + + align:start position:0% +condition you need a market structure + + + align:start position:0% +condition you need a market structure +condition to pin down the equilibrium + + align:start position:0% +condition to pin down the equilibrium + + + align:start position:0% +condition to pin down the equilibrium +for the last few lectures we relied on a + + align:start position:0% +for the last few lectures we relied on a + + + align:start position:0% +for the last few lectures we relied on a +particular Market structure which was + + align:start position:0% +particular Market structure which was + + + align:start position:0% +particular Market structure which was +perfect competition that allowed us to + + align:start position:0% +perfect competition that allowed us to + + + align:start position:0% +perfect competition that allowed us to +show that a perfect competition price + + align:start position:0% +show that a perfect competition price + + + align:start position:0% +show that a perfect competition price +equals marginal cost and that allowed us + + align:start position:0% +equals marginal cost and that allowed us + + + align:start position:0% +equals marginal cost and that allowed us +to solve the system for how firms choose + + align:start position:0% +to solve the system for how firms choose + + + align:start position:0% +to solve the system for how firms choose +their quantity and prices in perfect + + align:start position:0% +their quantity and prices in perfect + + + align:start position:0% +their quantity and prices in perfect +competition but as we discussed that's + + align:start position:0% +competition but as we discussed that's + + + align:start position:0% +competition but as we discussed that's +an incredibly extreme assumption and + + align:start position:0% +an incredibly extreme assumption and + + + align:start position:0% +an incredibly extreme assumption and +pretty much unrealistic for almost any + + align:start position:0% +pretty much unrealistic for almost any + + + align:start position:0% +pretty much unrealistic for almost any +Market there are some markets that more + + align:start position:0% +Market there are some markets that more + + + align:start position:0% +Market there are some markets that more +competitive than others but there's + + align:start position:0% +competitive than others but there's + + + align:start position:0% +competitive than others but there's +really no such thing as a perfectly + + align:start position:0% +really no such thing as a perfectly + + + align:start position:0% +really no such thing as a perfectly +competitive market so what we're going + + align:start position:0% +competitive market so what we're going + + + align:start position:0% +competitive market so what we're going +to do now is move on in the next few + + align:start position:0% +to do now is move on in the next few + + + align:start position:0% +to do now is move on in the next few +lectures and talk about Alternative + + align:start position:0% +lectures and talk about Alternative + + + align:start position:0% +lectures and talk about Alternative +Market structures and how they change + + align:start position:0% +Market structures and how they change + + + align:start position:0% +Market structures and how they change +the conclusions we draw this is going to + + align:start position:0% +the conclusions we draw this is going to + + + align:start position:0% +the conclusions we draw this is going to +be important for two reasons first of + + align:start position:0% +be important for two reasons first of + + + align:start position:0% +be important for two reasons first of +all it's going to be important because + + align:start position:0% +all it's going to be important because + + + align:start position:0% +all it's going to be important because +it's more + + align:start position:0% +it's more + + + align:start position:0% +it's more +realistic second of all is going be + + align:start position:0% +realistic second of all is going be + + + align:start position:0% +realistic second of all is going be +important because having established the + + align:start position:0% +important because having established the + + + align:start position:0% +important because having established the +first fundamental theorem of welfare + + align:start position:0% +first fundamental theorem of welfare + + + align:start position:0% +first fundamental theorem of welfare +economics which is the perfectly + + align:start position:0% +economics which is the perfectly + + + align:start position:0% +economics which is the perfectly +competitive outcome is the best outcome + + align:start position:0% +competitive outcome is the best outcome + + + align:start position:0% +competitive outcome is the best outcome +we're not going to talk you about why + + align:start position:0% +we're not going to talk you about why + + + align:start position:0% +we're not going to talk you about why +that doesn't work in reality and why in + + align:start position:0% +that doesn't work in reality and why in + + + align:start position:0% +that doesn't work in reality and why in +fact governments aren't just agents of + + align:start position:0% +fact governments aren't just agents of + + + align:start position:0% +fact governments aren't just agents of +chaos but can actually do good things in + + align:start position:0% +chaos but can actually do good things in + + + align:start position:0% +chaos but can actually do good things in +improving potential market failures so + + align:start position:0% +improving potential market failures so + + + align:start position:0% +improving potential market failures so +by introducing these Alternative Market + + align:start position:0% +by introducing these Alternative Market + + + align:start position:0% +by introducing these Alternative Market +structures will also juuce the concept + + align:start position:0% +structures will also juuce the concept + + + align:start position:0% +structures will also juuce the concept +of a market failure which is markets not + + align:start position:0% +of a market failure which is markets not + + + align:start position:0% +of a market failure which is markets not +working to deliver the efficient + + align:start position:0% +working to deliver the efficient + + + align:start position:0% +working to deliver the efficient +outcome so we're going to start today by + + align:start position:0% +outcome so we're going to start today by + + + align:start position:0% +outcome so we're going to start today by +talking about + + align:start position:0% +talking about + + + align:start position:0% +talking about +Monopoly so we're going to go from one + + align:start position:0% +Monopoly so we're going to go from one + + + align:start position:0% +Monopoly so we're going to go from one +extreme to another the one extreme we + + align:start position:0% +extreme to another the one extreme we + + + align:start position:0% +extreme to another the one extreme we +started with was a perfectly competitive + + align:start position:0% +started with was a perfectly competitive + + + align:start position:0% +started with was a perfectly competitive +market with a large number firms + + align:start position:0% +market with a large number firms + + + align:start position:0% +market with a large number firms +competing to deliver identical products + + align:start position:0% +competing to deliver identical products + + + align:start position:0% +competing to deliver identical products +we're going to move all the way to the + + align:start position:0% +we're going to move all the way to the + + + align:start position:0% +we're going to move all the way to the +Other Extreme which is Monopoly which is + + align:start position:0% +Other Extreme which is Monopoly which is + + + align:start position:0% +Other Extreme which is Monopoly which is +not the game but rather the name for a + + align:start position:0% +not the game but rather the name for a + + + align:start position:0% +not the game but rather the name for a +market with one + + align:start position:0% +market with one + + + align:start position:0% +market with one +firm that delivers all that delivers the + + align:start position:0% +firm that delivers all that delivers the + + + align:start position:0% +firm that delivers all that delivers the +goods for the entire Market s from uh + + align:start position:0% +goods for the entire Market s from uh + + + align:start position:0% +goods for the entire Market s from uh +many firms competing to one firm + + align:start position:0% +many firms competing to one firm + + + align:start position:0% +many firms competing to one firm +dominating the market and the key thing + + align:start position:0% +dominating the market and the key thing + + + align:start position:0% +dominating the market and the key thing +about Monopoly the key thing that's + + align:start position:0% +about Monopoly the key thing that's + + + align:start position:0% +about Monopoly the key thing that's +going to change is that firms are going + + align:start position:0% +going to change is that firms are going + + + align:start position:0% +going to change is that firms are going +to be price makers not just price acers + + align:start position:0% +to be price makers not just price acers + + + align:start position:0% +to be price makers not just price acers +remember in perfect competition the + + align:start position:0% +remember in perfect competition the + + + align:start position:0% +remember in perfect competition the +price was just sort of given to you from + + align:start position:0% +price was just sort of given to you from + + + align:start position:0% +price was just sort of given to you from +God it came from some market equilibrium + + align:start position:0% +God it came from some market equilibrium + + + align:start position:0% +God it came from some market equilibrium +you don't know where it came from you + + align:start position:0% +you don't know where it came from you + + + align:start position:0% +you don't know where it came from you +just knows the price and you couldn't + + align:start position:0% +just knows the price and you couldn't + + + align:start position:0% +just knows the price and you couldn't +affect it well that's kind of silly + + align:start position:0% +affect it well that's kind of silly + + + align:start position:0% +affect it well that's kind of silly +firms can obviously choose the prices + + align:start position:0% +firms can obviously choose the prices + + + align:start position:0% +firms can obviously choose the prices +they set so now we move to Monopoly + + align:start position:0% +they set so now we move to Monopoly + + + align:start position:0% +they set so now we move to Monopoly +we'll actually let firms be price price + + align:start position:0% +we'll actually let firms be price price + + + align:start position:0% +we'll actually let firms be price price +makers as well as price + + align:start position:0% +makers as well as price + + + align:start position:0% +makers as well as price +takers okay now in fact once again + + align:start position:0% +takers okay now in fact once again + + + align:start position:0% +takers okay now in fact once again +Monopoly is very extreme it's not + + align:start position:0% +Monopoly is very extreme it's not + + + align:start position:0% +Monopoly is very extreme it's not +extreme perfect competition monopolies + + align:start position:0% +extreme perfect competition monopolies + + + align:start position:0% +extreme perfect competition monopolies +do exist even if perfectly competitive + + align:start position:0% +do exist even if perfectly competitive + + + align:start position:0% +do exist even if perfectly competitive +markets don't but but it's still a + + align:start position:0% +markets don't but but it's still a + + + align:start position:0% +markets don't but but it's still a +relatively small share of reality after + + align:start position:0% +relatively small share of reality after + + + align:start position:0% +relatively small share of reality after +a couple lectures of Monopoly we'll then + + align:start position:0% +a couple lectures of Monopoly we'll then + + + align:start position:0% +a couple lectures of Monopoly we'll then +turn to the more realistic case in my + + align:start position:0% +turn to the more realistic case in my + + + align:start position:0% +turn to the more realistic case in my +favorite word in economics + + align:start position:0% +favorite word in economics + + + align:start position:0% +favorite word in economics +oligopoly which is the case of several + + align:start position:0% +oligopoly which is the case of several + + + align:start position:0% +oligopoly which is the case of several +firms competing where this competition + + align:start position:0% +firms competing where this competition + + + align:start position:0% +firms competing where this competition +but it's less than perfect competition + + align:start position:0% +but it's less than perfect competition + + + align:start position:0% +but it's less than perfect competition +and we'll come back to that but for the + + align:start position:0% +and we'll come back to that but for the + + + align:start position:0% +and we'll come back to that but for the +next two lectures we're going to move to + + align:start position:0% +next two lectures we're going to move to + + + align:start position:0% +next two lectures we're going to move to +the Other Extreme which is Monopoly okay + + align:start position:0% +the Other Extreme which is Monopoly okay + + + align:start position:0% +the Other Extreme which is Monopoly okay +and we're talk today about how + + align:start position:0% +and we're talk today about how + + + align:start position:0% +and we're talk today about how +monopolists maximize profits how to + + align:start position:0% +monopolists maximize profits how to + + + align:start position:0% +monopolists maximize profits how to +monopolis maximize + + align:start position:0% +monopolis maximize + + + align:start position:0% +monopolis maximize +profits okay well to do that we're going + + align:start position:0% +profits okay well to do that we're going + + + align:start position:0% +profits okay well to do that we're going +to turn to a + + align:start position:0% +to turn to a + + + align:start position:0% +to turn to a +concept that we've already talked about + + align:start position:0% +concept that we've already talked about + + + align:start position:0% +concept that we've already talked about +but it's been sort of meaningless so far + + align:start position:0% +but it's been sort of meaningless so far + + + align:start position:0% +but it's been sort of meaningless so far +which is the concept of marginal + + align:start position:0% + + + + align:start position:0% + +revenue the marginal revenue is the + + align:start position:0% +revenue the marginal revenue is the + + + align:start position:0% +revenue the marginal revenue is the +revenue you earn on the next unit you + + align:start position:0% +revenue you earn on the next unit you + + + align:start position:0% +revenue you earn on the next unit you +sell which in perfect competition wasn't + + align:start position:0% +sell which in perfect competition wasn't + + + align:start position:0% +sell which in perfect competition wasn't +interesting it was just the + + align:start position:0% +interesting it was just the + + + align:start position:0% +interesting it was just the +price but it's going to get more + + align:start position:0% +price but it's going to get more + + + align:start position:0% +price but it's going to get more +interesting + + align:start position:0% +interesting + + + align:start position:0% +interesting +today okay so we're going to talk about + + align:start position:0% +today okay so we're going to talk about + + + align:start position:0% +today okay so we're going to talk about +what happen so let's go back + + align:start position:0% +what happen so let's go back + + + align:start position:0% +what happen so let's go back +and think about a perfectly competitive + + align:start position:0% +and think about a perfectly competitive + + + align:start position:0% +and think about a perfectly competitive +firm and think about what their marginal + + align:start position:0% +firm and think about what their marginal + + + align:start position:0% +firm and think about what their marginal +revenues so in figure + + align:start position:0% +revenues so in figure + + + align:start position:0% +revenues so in figure +111 you have a perfectly competitive + + align:start position:0% +111 you have a perfectly competitive + + + align:start position:0% +111 you have a perfectly competitive +firm they The Firm M faces a perfectly + + align:start position:0% +firm they The Firm M faces a perfectly + + + align:start position:0% +firm they The Firm M faces a perfectly +elastic demand curve a perfectly + + align:start position:0% +elastic demand curve a perfectly + + + align:start position:0% +elastic demand curve a perfectly +competitive firm this doesn't mean the + + align:start position:0% +competitive firm this doesn't mean the + + + align:start position:0% +competitive firm this doesn't mean the +market demand's elastic but each firm in + + align:start position:0% +market demand's elastic but each firm in + + + align:start position:0% +market demand's elastic but each firm in +perfect competition faces a perfectly + + align:start position:0% +perfect competition faces a perfectly + + + align:start position:0% +perfect competition faces a perfectly +elastic demand curve so if they sell + + align:start position:0% +elastic demand curve so if they sell + + + align:start position:0% +elastic demand curve so if they sell +little Q units they make Revenue + + align:start position:0% +little Q units they make Revenue + + + align:start position:0% +little Q units they make Revenue +a if they sell Q plus1 units they make + + align:start position:0% +a if they sell Q plus1 units they make + + + align:start position:0% +a if they sell Q plus1 units they make +Revenue a plus b they add B well we know + + align:start position:0% +Revenue a plus b they add B well we know + + + align:start position:0% +Revenue a plus b they add B well we know +what B is the width is one and the + + align:start position:0% +what B is the width is one and the + + + align:start position:0% +what B is the width is one and the +height is the price so the marginal + + align:start position:0% +height is the price so the marginal + + + align:start position:0% +height is the price so the marginal +revenue from selling the Q plus plus one + + align:start position:0% +revenue from selling the Q plus plus one + + + align:start position:0% +revenue from selling the Q plus plus one +unit plus one + + align:start position:0% +unit plus one + + + align:start position:0% +unit plus one +unit is the price okay it's just an + + align:start position:0% +unit is the price okay it's just an + + + align:start position:0% +unit is the price okay it's just an +illustration what we learned before + + align:start position:0% +illustration what we learned before + + + align:start position:0% +illustration what we learned before +Monopoly is going to be different and in + + align:start position:0% +Monopoly is going to be different and in + + + align:start position:0% +Monopoly is going to be different and in +particular monopo is going to be + + align:start position:0% +particular monopo is going to be + + + align:start position:0% +particular monopo is going to be +different because we're going to make a + + align:start position:0% +different because we're going to make a + + + align:start position:0% +different because we're going to make a +critical + + align:start position:0% +critical + + + align:start position:0% +critical +assumption for how monopolis behave we + + align:start position:0% +assumption for how monopolis behave we + + + align:start position:0% +assumption for how monopolis behave we +are going to assume + + align:start position:0% +are going to assume + + + align:start position:0% +are going to assume +that + + align:start position:0% +that + + + align:start position:0% +that +monopolis that um we're assume that + + align:start position:0% +monopolis that um we're assume that + + + align:start position:0% +monopolis that um we're assume that +monopolis uh cannot price + + align:start position:0% + + + + align:start position:0% + +discriminate that is when a monopolis + + align:start position:0% +discriminate that is when a monopolis + + + align:start position:0% +discriminate that is when a monopolis +sets a + + align:start position:0% +sets a + + + align:start position:0% +sets a +price they set that price for All units + + align:start position:0% +price they set that price for All units + + + align:start position:0% +price they set that price for All units +they sell so monopolis sets the price + + align:start position:0% +they sell so monopolis sets the price + + + align:start position:0% +they sell so monopolis sets the price +they're price maker but it's not quite + + align:start position:0% +they're price maker but it's not quite + + + align:start position:0% +they're price maker but it's not quite +free Price setting because we're not + + align:start position:0% +free Price setting because we're not + + + align:start position:0% +free Price setting because we're not +going to let them set a different price + + align:start position:0% +going to let them set a different price + + + align:start position:0% +going to let them set a different price +to me and you when they set price they + + align:start position:0% +to me and you when they set price they + + + align:start position:0% +to me and you when they set price they +set the price for everyone so we're + + align:start position:0% +set the price for everyone so we're + + + align:start position:0% +set the price for everyone so we're +going to assume no price discrimination + + align:start position:0% +going to assume no price discrimination + + + align:start position:0% +going to assume no price discrimination +we'll come back to that but for now + + align:start position:0% +we'll come back to that but for now + + + align:start position:0% +we'll come back to that but for now +we're going to say that when I'm we're + + align:start position:0% +we're going to say that when I'm we're + + + align:start position:0% +we're going to say that when I'm we're +going to let the monopolis set his price + + align:start position:0% +going to let the monopolis set his price + + + align:start position:0% +going to let the monopolis set his price +but critically it's one price for + + align:start position:0% +but critically it's one price for + + + align:start position:0% +but critically it's one price for +everyone and you'll see in a minute why + + align:start position:0% +everyone and you'll see in a minute why + + + align:start position:0% +everyone and you'll see in a minute why +this is + + align:start position:0% +this is + + + align:start position:0% +this is +important okay so to understand that + + align:start position:0% +important okay so to understand that + + + align:start position:0% +important okay so to understand that +let's go to figure + + align:start position:0% +let's go to figure + + + align:start position:0% +let's go to figure +112 112 is for Monopoly Market all + + align:start position:0% +112 112 is for Monopoly Market all + + + align:start position:0% +112 112 is for Monopoly Market all +that's changed + + align:start position:0% +that's changed + + + align:start position:0% +that's changed +here is that now firm demand is market + + align:start position:0% +here is that now firm demand is market + + + align:start position:0% +here is that now firm demand is market +demand + + align:start position:0% +demand + + + align:start position:0% +demand +okay with perfect competition firm + + align:start position:0% +okay with perfect competition firm + + + align:start position:0% +okay with perfect competition firm +demand was perfectly elastic because + + align:start position:0% +demand was perfectly elastic because + + + align:start position:0% +demand was perfectly elastic because +there are many firms but now firm + + align:start position:0% +there are many firms but now firm + + + align:start position:0% +there are many firms but now firm +demand's market demand and unless the + + align:start position:0% +demand's market demand and unless the + + + align:start position:0% +demand's market demand and unless the +market itself features perfectly elastic + + align:start position:0% +market itself features perfectly elastic + + + align:start position:0% +market itself features perfectly elastic +demand The Firm will now face a downward + + align:start position:0% +demand The Firm will now face a downward + + + align:start position:0% +demand The Firm will now face a downward +sloping demand curve so now little Q is + + align:start position:0% +sloping demand curve so now little Q is + + + align:start position:0% +sloping demand curve so now little Q is +Big Q you notice on the x- axis I moved + + align:start position:0% +Big Q you notice on the x- axis I moved + + + align:start position:0% +Big Q you notice on the x- axis I moved +to Big Q which we used to refer to the + + align:start position:0% +to Big Q which we used to refer to the + + + align:start position:0% +to Big Q which we used to refer to the +market well with Monopoly markets little + + align:start position:0% +market well with Monopoly markets little + + + align:start position:0% +market well with Monopoly markets little +Q is Big Q there's one firm so the firm + + align:start position:0% +Q is Big Q there's one firm so the firm + + + align:start position:0% +Q is Big Q there's one firm so the firm +is the market and that firm faces a + + align:start position:0% +is the market and that firm faces a + + + align:start position:0% +is the market and that firm faces a +downward sloping demand curve so let's + + align:start position:0% +downward sloping demand curve so let's + + + align:start position:0% +downward sloping demand curve so let's +say that firm initially wants to sell Q + + align:start position:0% +say that firm initially wants to sell Q + + + align:start position:0% +say that firm initially wants to sell Q +q1 I'm sorry want sell Q if it wants to + + align:start position:0% +q1 I'm sorry want sell Q if it wants to + + + align:start position:0% +q1 I'm sorry want sell Q if it wants to +sell + + align:start position:0% +sell + + + align:start position:0% +sell +Q it has to respect demand so if it + + align:start position:0% +Q it has to respect demand so if it + + + align:start position:0% +Q it has to respect demand so if it +wants to sell Q it's going to set the + + align:start position:0% +wants to sell Q it's going to set the + + + align:start position:0% +wants to sell Q it's going to set the +price at + + align:start position:0% +price at + + + align:start position:0% +price at +P1 a price of P1 allows them to sell Q + + align:start position:0% +P1 a price of P1 allows them to sell Q + + + align:start position:0% +P1 a price of P1 allows them to sell Q +units remember they get set the price + + align:start position:0% +units remember they get set the price + + + align:start position:0% +units remember they get set the price +now so price of P1 allows to sell Q + + align:start position:0% +now so price of P1 allows to sell Q + + + align:start position:0% +now so price of P1 allows to sell Q +units now imagine they want to sell one + + align:start position:0% +units now imagine they want to sell one + + + align:start position:0% +units now imagine they want to sell one +more + + align:start position:0% +more + + + align:start position:0% +more +unit what happens well two things happen + + align:start position:0% +unit what happens well two things happen + + + align:start position:0% +unit what happens well two things happen +okay and in particular if they want to + + align:start position:0% +okay and in particular if they want to + + + align:start position:0% +okay and in particular if they want to +sell one more + + align:start position:0% +sell one more + + + align:start position:0% +sell one more +unit okay they have to lower the + + align:start position:0% +unit okay they have to lower the + + + align:start position:0% +unit okay they have to lower the +price why because demand is downward + + align:start position:0% +price why because demand is downward + + + align:start position:0% +price why because demand is downward +sloping and there's just one price so if + + align:start position:0% +sloping and there's just one price so if + + + align:start position:0% +sloping and there's just one price so if +the monopolis wants to move from selling + + align:start position:0% +the monopolis wants to move from selling + + + align:start position:0% +the monopolis wants to move from selling +Q to selling q+ one it has to lower the + + align:start position:0% +Q to selling q+ one it has to lower the + + + align:start position:0% +Q to selling q+ one it has to lower the +price from P1 to P2 there's no choice it + + align:start position:0% +price from P1 to P2 there's no choice it + + + align:start position:0% +price from P1 to P2 there's no choice it +has to be on the demand + + align:start position:0% +has to be on the demand + + + align:start position:0% +has to be on the demand +curve so when the anopolis wants to + + align:start position:0% +curve so when the anopolis wants to + + + align:start position:0% +curve so when the anopolis wants to +sell two more two + + align:start position:0% +sell two more two + + + align:start position:0% +sell two more two +units okay the marginal revenue they get + + align:start position:0% +units okay the marginal revenue they get + + + align:start position:0% +units okay the marginal revenue they get +want sell one more unit they get the + + align:start position:0% +want sell one more unit they get the + + + align:start position:0% +want sell one more unit they get the +amount + + align:start position:0% +amount + + + align:start position:0% +amount +B which they sell one more unit at the + + align:start position:0% +B which they sell one more unit at the + + + align:start position:0% +B which they sell one more unit at the +price P2 but they lose the amount + + align:start position:0% +price P2 but they lose the amount + + + align:start position:0% +price P2 but they lose the amount +C they get the amount B but they lose + + align:start position:0% +C they get the amount B but they lose + + + align:start position:0% +C they get the amount B but they lose +the amount C or in other words what do + + align:start position:0% +the amount C or in other words what do + + + align:start position:0% +the amount C or in other words what do +they what does a monopolis get from + + align:start position:0% +they what does a monopolis get from + + + align:start position:0% +they what does a monopolis get from +selling one more unit monopis say sells + + align:start position:0% +selling one more unit monopis say sells + + + align:start position:0% +selling one more unit monopis say sells +one more unit the monopolis gets P2 + + align:start position:0% +one more unit the monopolis gets P2 + + + align:start position:0% +one more unit the monopolis gets P2 +minus P1 + + align:start position:0% +minus P1 + + + align:start position:0% +minus P1 +times um I'm sorry P2 + + align:start position:0% +times um I'm sorry P2 + + + align:start position:0% +times um I'm sorry P2 +minus P2 minus P1 minus P2 * + + align:start position:0% + + + + align:start position:0% + +q1 okay the monopolist gets some money + + align:start position:0% +q1 okay the monopolist gets some money + + + align:start position:0% +q1 okay the monopolist gets some money +from selling additional unit but loses + + align:start position:0% +from selling additional unit but loses + + + align:start position:0% +from selling additional unit but loses +some money because it had to lower the + + align:start position:0% +some money because it had to lower the + + + align:start position:0% +some money because it had to lower the +price on all its previous units you + + align:start position:0% +price on all its previous units you + + + align:start position:0% +price on all its previous units you +might say that once again stop and think + + align:start position:0% +might say that once again stop and think + + + align:start position:0% +might say that once again stop and think +for me for a second it doesn't make + + align:start position:0% +for me for a second it doesn't make + + + align:start position:0% +for me for a second it doesn't make +sense why does it have to well it has to + + align:start position:0% +sense why does it have to well it has to + + + align:start position:0% +sense why does it have to well it has to +because it can only set one + + align:start position:0% +because it can only set one + + + align:start position:0% +because it can only set one +price so if it wants to set sell more + + align:start position:0% +price so if it wants to set sell more + + + align:start position:0% +price so if it wants to set sell more +it's got to set a lower price which + + align:start position:0% +it's got to set a lower price which + + + align:start position:0% +it's got to set a lower price which +means it's going to make less than all + + align:start position:0% +means it's going to make less than all + + + align:start position:0% +means it's going to make less than all +its previous + + align:start position:0% +its previous + + + align:start position:0% +its previous +units okay so basically when the + + align:start position:0% +units okay so basically when the + + + align:start position:0% +units okay so basically when the +monopolis sets the price there's now a + + align:start position:0% +monopolis sets the price there's now a + + + align:start position:0% +monopolis sets the price there's now a +tradeoff the tradeoff is if he wants to + + align:start position:0% +tradeoff the tradeoff is if he wants to + + + align:start position:0% +tradeoff the tradeoff is if he wants to +sell more he has to lower the price but + + align:start position:0% +sell more he has to lower the price but + + + align:start position:0% +sell more he has to lower the price but +in doing so the monopolis makes less + + align:start position:0% +in doing so the monopolis makes less + + + align:start position:0% +in doing so the monopolis makes less +money on the previous units they + + align:start position:0% +money on the previous units they + + + align:start position:0% +money on the previous units they +sold okay and that's because they set + + align:start position:0% +sold okay and that's because they set + + + align:start position:0% +sold okay and that's because they set +the same price price for All consumers + + align:start position:0% +the same price price for All consumers + + + align:start position:0% +the same price price for All consumers +this is the key intuition that drives + + align:start position:0% +this is the key intuition that drives + + + align:start position:0% +this is the key intuition that drives +our analysis of + + align:start position:0% +our analysis of + + + align:start position:0% +our analysis of +Monopoly okay I like to refer to + + align:start position:0% +Monopoly okay I like to refer to + + + align:start position:0% +Monopoly okay I like to refer to +this as what I call the poisoning + + align:start position:0% +this as what I call the poisoning + + + align:start position:0% +this as what I call the poisoning +effect I call it the poisoning effect + + align:start position:0% +effect I call it the poisoning effect + + + align:start position:0% +effect I call it the poisoning effect +it's just the term I like to use because + + align:start position:0% +it's just the term I like to use because + + + align:start position:0% +it's just the term I like to use because +the idea is if I want to sell one more + + align:start position:0% +the idea is if I want to sell one more + + + align:start position:0% +the idea is if I want to sell one more +unit I have to poison all my previous + + align:start position:0% +unit I have to poison all my previous + + + align:start position:0% +unit I have to poison all my previous +sales by lowering their + + align:start position:0% +sales by lowering their + + + align:start position:0% +sales by lowering their +price because I can't sell another unit + + align:start position:0% +price because I can't sell another unit + + + align:start position:0% +price because I can't sell another unit +without a lower price and if I lower + + align:start position:0% +without a lower price and if I lower + + + align:start position:0% +without a lower price and if I lower +price I make less money on my previous + + align:start position:0% +price I make less money on my previous + + + align:start position:0% +price I make less money on my previous +sales okay don't think it's a changing + + align:start position:0% +sales okay don't think it's a changing + + + align:start position:0% +sales okay don't think it's a changing +your price day by day think of this I + + align:start position:0% +your price day by day think of this I + + + align:start position:0% +your price day by day think of this I +have to set one price + + align:start position:0% + + + + align:start position:0% + +yeah yes this is the marginal this is + + align:start position:0% +yeah yes this is the marginal this is + + + align:start position:0% +yeah yes this is the marginal this is +the marginal + + align:start position:0% + + + + align:start position:0% + +revenue yeah P P1 minus P2 * q1 it's in + + align:start position:0% +revenue yeah P P1 minus P2 * q1 it's in + + + align:start position:0% +revenue yeah P P1 minus P2 * q1 it's in +parenthesis okay so basically the + + align:start position:0% +parenthesis okay so basically the + + + align:start position:0% +parenthesis okay so basically the +marginal revenue is if I if I want to + + align:start position:0% +marginal revenue is if I if I want to + + + align:start position:0% +marginal revenue is if I if I want to +sell one more unit I get P2 for that + + align:start position:0% +sell one more unit I get P2 for that + + + align:start position:0% +sell one more unit I get P2 for that +unit that's what I get for that unit but + + align:start position:0% +unit that's what I get for that unit but + + + align:start position:0% +unit that's what I get for that unit but +I give up what I was making on all the + + align:start position:0% +I give up what I was making on all the + + + align:start position:0% +I give up what I was making on all the +old units the difference in the price + + align:start position:0% +old units the difference in the price + + + align:start position:0% +old units the difference in the price +that I was making on all the old + + align:start position:0% +that I was making on all the old + + + align:start position:0% +that I was making on all the old +units okay and that is basically the + + align:start position:0% +units okay and that is basically the + + + align:start position:0% +units okay and that is basically the +definition of marginal revenue in the + + align:start position:0% +definition of marginal revenue in the + + + align:start position:0% +definition of marginal revenue in the +monopolis case so in other words more + + align:start position:0% +monopolis case so in other words more + + + align:start position:0% +monopolis case so in other words more +generally if you write Revenue as P * Q + + align:start position:0% +generally if you write Revenue as P * Q + + + align:start position:0% +generally if you write Revenue as P * Q +then marginal revenue you can write if + + align:start position:0% +then marginal revenue you can write if + + + align:start position:0% +then marginal revenue you can write if +you write P * Q the marginal revenue is + + align:start position:0% +you write P * Q the marginal revenue is + + + align:start position:0% +you write P * Q the marginal revenue is +uh Dr DQ okay if you take margin with + + align:start position:0% +uh Dr DQ okay if you take margin with + + + align:start position:0% +uh Dr DQ okay if you take margin with +respect to Q is + + align:start position:0% +respect to Q is + + + align:start position:0% +respect to Q is +Dr + + align:start position:0% +Dr + + + align:start position:0% +Dr +DQ well that equals P plus + + align:start position:0% +DQ well that equals P plus + + + align:start position:0% +DQ well that equals P plus +d p DQ time + + align:start position:0% +d p DQ time + + + align:start position:0% +d p DQ time +Q so when you want to sell one more unit + + align:start position:0% +Q so when you want to sell one more unit + + + align:start position:0% +Q so when you want to sell one more unit +if I the marginal revenue there's a + + align:start position:0% +if I the marginal revenue there's a + + + align:start position:0% +if I the marginal revenue there's a +positive term which I sell one more unit + + align:start position:0% +positive term which I sell one more unit + + + align:start position:0% +positive term which I sell one more unit +but there's a negative term which is I + + align:start position:0% +but there's a negative term which is I + + + align:start position:0% +but there's a negative term which is I +had to lower my price to sell that + + align:start position:0% +had to lower my price to sell that + + + align:start position:0% +had to lower my price to sell that +unit so when I'm setting my price I have + + align:start position:0% +unit so when I'm setting my price I have + + + align:start position:0% +unit so when I'm setting my price I have +to trade these things + + align:start position:0% +to trade these things + + + align:start position:0% +to trade these things +off okay I have to trade these things + + align:start position:0% +off okay I have to trade these things + + + align:start position:0% +off okay I have to trade these things +off which is basically that I have to + + align:start position:0% +off which is basically that I have to + + + align:start position:0% +off which is basically that I have to +trade off the fact that I'm make I'm + + align:start position:0% +trade off the fact that I'm make I'm + + + align:start position:0% +trade off the fact that I'm make I'm +going to sell more units but I'm going + + align:start position:0% +going to sell more units but I'm going + + + align:start position:0% +going to sell more units but I'm going +to make um make less money to each unit + + align:start position:0% +to make um make less money to each unit + + + align:start position:0% +to make um make less money to each unit +Why didn't the competitive firm face + + align:start position:0% +Why didn't the competitive firm face + + + align:start position:0% +Why didn't the competitive firm face +this + + align:start position:0% +this + + + align:start position:0% +this +tradeoff why why was this trade-off not + + align:start position:0% +tradeoff why why was this trade-off not + + + align:start position:0% +tradeoff why why was this trade-off not +an issue for the competitive firm + + align:start position:0% +an issue for the competitive firm + + + align:start position:0% +an issue for the competitive firm +mathematically what's different from the + + align:start position:0% +mathematically what's different from the + + + align:start position:0% +mathematically what's different from the +competitive + + align:start position:0% +competitive + + + align:start position:0% +competitive +firm yeah + + align:start position:0% +firm yeah + + + align:start position:0% +firm yeah +dpq is zero for the competitive firm + + align:start position:0% +dpq is zero for the competitive firm + + + align:start position:0% +dpq is zero for the competitive firm +because it's a price taker it can sell + + align:start position:0% +because it's a price taker it can sell + + + align:start position:0% +because it's a price taker it can sell +as much as it wants at the market + + align:start position:0% +as much as it wants at the market + + + align:start position:0% +as much as it wants at the market +price so for the competitive firm March + + align:start position:0% +price so for the competitive firm March + + + align:start position:0% +price so for the competitive firm March +revenue is just + + align:start position:0% +revenue is just + + + align:start position:0% +revenue is just +price but for the monopis that's not + + align:start position:0% +price but for the monopis that's not + + + align:start position:0% +price but for the monopis that's not +true by to sell more it has to lower the + + align:start position:0% +true by to sell more it has to lower the + + + align:start position:0% +true by to sell more it has to lower the +price okay so we can graph a monopolis + + align:start position:0% +price okay so we can graph a monopolis + + + align:start position:0% +price okay so we can graph a monopolis +marginal revenue curve and we'll do that + + align:start position:0% +marginal revenue curve and we'll do that + + + align:start position:0% +marginal revenue curve and we'll do that +in figure 113 so let's go through the + + align:start position:0% +in figure 113 so let's go through the + + + align:start position:0% +in figure 113 so let's go through the +math here let's do an + + align:start position:0% +math here let's do an + + + align:start position:0% +math here let's do an +example imagine we have an example where + + align:start position:0% +example imagine we have an example where + + + align:start position:0% +example imagine we have an example where +demand is described by the equation Q = + + align:start position:0% +demand is described by the equation Q = + + + align:start position:0% +demand is described by the equation Q = +24 minus P just a standard well- behaved + + align:start position:0% +24 minus P just a standard well- behaved + + + align:start position:0% +24 minus P just a standard well- behaved +demand equation you know how to derive + + align:start position:0% +demand equation you know how to derive + + + align:start position:0% +demand equation you know how to derive +that from utility okay imagine that's + + align:start position:0% +that from utility okay imagine that's + + + align:start position:0% +that from utility okay imagine that's +the demand + + align:start position:0% +the demand + + + align:start position:0% +the demand +equation well the first step to solve a + + align:start position:0% +equation well the first step to solve a + + + align:start position:0% +equation well the first step to solve a +monopoly problem is let's rewrite this + + align:start position:0% +monopoly problem is let's rewrite this + + + align:start position:0% +monopoly problem is let's rewrite this +as P equal 24 minus Q makes the math a + + align:start position:0% +as P equal 24 minus Q makes the math a + + + align:start position:0% +as P equal 24 minus Q makes the math a +little + + align:start position:0% +little + + + align:start position:0% +little +easier and now let's multiply both sides + + align:start position:0% +easier and now let's multiply both sides + + + align:start position:0% +easier and now let's multiply both sides +by Q to make it a revenue equation so + + align:start position:0% +by Q to make it a revenue equation so + + + align:start position:0% +by Q to make it a revenue equation so +Revenue which is p * Q = 24 Q - Q ^2 + + align:start position:0% +Revenue which is p * Q = 24 Q - Q ^2 + + + align:start position:0% +Revenue which is p * Q = 24 Q - Q ^2 +that's the revenue that the firm earns + + align:start position:0% +that's the revenue that the firm earns + + + align:start position:0% +that's the revenue that the firm earns +it's p which comes from demand times the + + align:start position:0% +it's p which comes from demand times the + + + align:start position:0% +it's p which comes from demand times the +amount of units sold differentiating + + align:start position:0% +amount of units sold differentiating + + + align:start position:0% +amount of units sold differentiating +this marginal revenue is 24 minus 2 + + align:start position:0% + + + + align:start position:0% + +Q that's the marginal revenue curve for + + align:start position:0% +Q that's the marginal revenue curve for + + + align:start position:0% +Q that's the marginal revenue curve for +that firm and you can see this in figure + + align:start position:0% +that firm and you can see this in figure + + + align:start position:0% +that firm and you can see this in figure +113 here we graph the demain curve + + align:start position:0% +113 here we graph the demain curve + + + align:start position:0% +113 here we graph the demain curve +that's the Blue Line the demand curve is + + align:start position:0% +that's the Blue Line the demand curve is + + + align:start position:0% +that's the Blue Line the demand curve is +just a standard demand curve where you + + align:start position:0% +just a standard demand curve where you + + + align:start position:0% +just a standard demand curve where you +can have 24 units per day at a price of + + align:start position:0% +can have 24 units per day at a price of + + + align:start position:0% +can have 24 units per day at a price of +zero and you want zero units per day at + + align:start position:0% +zero and you want zero units per day at + + + align:start position:0% +zero and you want zero units per day at +a price of + + align:start position:0% +a price of + + + align:start position:0% +a price of +24 okay and then the the marginal + + align:start position:0% +24 okay and then the the marginal + + + align:start position:0% +24 okay and then the the marginal +revenue curve is everywhere below the + + align:start position:0% +revenue curve is everywhere below the + + + align:start position:0% +revenue curve is everywhere below the +demand curve it has the same + + align:start position:0% +demand curve it has the same + + + align:start position:0% +demand curve it has the same +intersection on the y- axis but it's + + align:start position:0% +intersection on the y- axis but it's + + + align:start position:0% +intersection on the y- axis but it's +everywhere below the demand curve is the + + align:start position:0% +everywhere below the demand curve is the + + + align:start position:0% +everywhere below the demand curve is the +marginal revenue curve now um the fact + + align:start position:0% +marginal revenue curve now um the fact + + + align:start position:0% +marginal revenue curve now um the fact +that the margin Ry curve starts at the + + align:start position:0% +that the margin Ry curve starts at the + + + align:start position:0% +that the margin Ry curve starts at the +same Y intercept is not General it's + + align:start position:0% +same Y intercept is not General it's + + + align:start position:0% +same Y intercept is not General it's +only because this is linear in a + + align:start position:0% +only because this is linear in a + + + align:start position:0% +only because this is linear in a +nonlinear case the margin Ry curve can + + align:start position:0% +nonlinear case the margin Ry curve can + + + align:start position:0% +nonlinear case the margin Ry curve can +start at a different Y intercept but the + + align:start position:0% +start at a different Y intercept but the + + + align:start position:0% +start at a different Y intercept but the +fact that margin revenue is everywhere + + align:start position:0% +fact that margin revenue is everywhere + + + align:start position:0% +fact that margin revenue is everywhere +below demand is + + align:start position:0% +below demand is + + + align:start position:0% +below demand is +General margin revenue is always below + + align:start position:0% +General margin revenue is always below + + + align:start position:0% +General margin revenue is always below +demand okay because of this poisoning + + align:start position:0% +demand okay because of this poisoning + + + align:start position:0% +demand okay because of this poisoning +effect Marg revenue is always below uh + + align:start position:0% +effect Marg revenue is always below uh + + + align:start position:0% +effect Marg revenue is always below uh +demand okay questions about that this is + + align:start position:0% +demand okay questions about that this is + + + align:start position:0% +demand okay questions about that this is +not a simple intuition so questions + + align:start position:0% +not a simple intuition so questions + + + align:start position:0% +not a simple intuition so questions +about how this works + + align:start position:0% + + + + align:start position:0% + +okay well arm with that let's talk about + + align:start position:0% +okay well arm with that let's talk about + + + align:start position:0% +okay well arm with that let's talk about +how monopolis maximize profits let's go + + align:start position:0% +how monopolis maximize profits let's go + + + align:start position:0% +how monopolis maximize profits let's go +to figure 114 figure + + align:start position:0% +to figure 114 figure + + + align:start position:0% +to figure 114 figure +114 I'm going to now add a cost function + + align:start position:0% +114 I'm going to now add a cost function + + + align:start position:0% +114 I'm going to now add a cost function +let me say that + + align:start position:0% +let me say that + + + align:start position:0% +let me say that +C equals I'm just going to assume C + + align:start position:0% +C equals I'm just going to assume C + + + align:start position:0% +C equals I'm just going to assume C +equals 12 plus + + align:start position:0% +equals 12 plus + + + align:start position:0% +equals 12 plus +q^2 I'm just making just once again you + + align:start position:0% +q^2 I'm just making just once again you + + + align:start position:0% +q^2 I'm just making just once again you +know how to derive that if I gave you + + align:start position:0% +know how to derive that if I gave you + + + align:start position:0% +know how to derive that if I gave you +production function input prices you + + align:start position:0% +production function input prices you + + + align:start position:0% +production function input prices you +could derive that okay but I'm just + + align:start position:0% +could derive that okay but I'm just + + + align:start position:0% +could derive that okay but I'm just +going to assume Cal 12+ q^2 so in that + + align:start position:0% +going to assume Cal 12+ q^2 so in that + + + align:start position:0% +going to assume Cal 12+ q^2 so in that +case + + align:start position:0% +case + + + align:start position:0% +case +what do we know we can draft we can + + align:start position:0% +what do we know we can draft we can + + + align:start position:0% +what do we know we can draft we can +graph the marginal cost marginal cost is + + align:start position:0% +graph the marginal cost marginal cost is + + + align:start position:0% +graph the marginal cost marginal cost is +just 2 Q right that's the marginal cost + + align:start position:0% +just 2 Q right that's the marginal cost + + + align:start position:0% +just 2 Q right that's the marginal cost +line in figure 114 marginal cost is 2 Q + + align:start position:0% +line in figure 114 marginal cost is 2 Q + + + align:start position:0% +line in figure 114 marginal cost is 2 Q +we can graph average total cost average + + align:start position:0% +we can graph average total cost average + + + align:start position:0% +we can graph average total cost average +variable cost and average fixed cost + + align:start position:0% +variable cost and average fixed cost + + + align:start position:0% +variable cost and average fixed cost +those are all things we learned to graph + + align:start position:0% +those are all things we learned to graph + + + align:start position:0% +those are all things we learned to graph +before we can put those all in the + + align:start position:0% +before we can put those all in the + + + align:start position:0% +before we can put those all in the +graph okay now we can solve for the + + align:start position:0% +graph okay now we can solve for the + + + align:start position:0% +graph okay now we can solve for the +Monopoly profit maximizing decision + + align:start position:0% +Monopoly profit maximizing decision + + + align:start position:0% +Monopoly profit maximizing decision +remember profit maximization always + + align:start position:0% +remember profit maximization always + + + align:start position:0% +remember profit maximization always +happens regardless of Market + + align:start position:0% +happens regardless of Market + + + align:start position:0% +happens regardless of Market +structure profit maximization happens + + align:start position:0% +structure profit maximization happens + + + align:start position:0% +structure profit maximization happens +when marginal revenue equals marginal + + align:start position:0% +when marginal revenue equals marginal + + + align:start position:0% +when marginal revenue equals marginal +cost right remember just to remind you + + align:start position:0% +cost right remember just to remind you + + + align:start position:0% +cost right remember just to remind you +profits equals Revenue Minus cost so to + + align:start position:0% +profits equals Revenue Minus cost so to + + + align:start position:0% +profits equals Revenue Minus cost so to +maximize this we say marginal revenue uh + + align:start position:0% +maximize this we say marginal revenue uh + + + align:start position:0% +maximize this we say marginal revenue uh +minus marginal cost equals zero that's + + align:start position:0% +minus marginal cost equals zero that's + + + align:start position:0% +minus marginal cost equals zero that's +how we maximize profits right so if + + align:start position:0% +how we maximize profits right so if + + + align:start position:0% +how we maximize profits right so if +profits is revenue Minus cost and + + align:start position:0% +profits is revenue Minus cost and + + + align:start position:0% +profits is revenue Minus cost and +profits are maximized or marginal rumiz + + align:start position:0% +profits are maximized or marginal rumiz + + + align:start position:0% +profits are maximized or marginal rumiz +marginal cost equals zero so the profit + + align:start position:0% +marginal cost equals zero so the profit + + + align:start position:0% +marginal cost equals zero so the profit +maximizing condition is marginal revenue + + align:start position:0% +maximizing condition is marginal revenue + + + align:start position:0% +maximizing condition is marginal revenue +equals marginal + + align:start position:0% +equals marginal + + + align:start position:0% +equals marginal +cost okay that's true with any Market + + align:start position:0% +cost okay that's true with any Market + + + align:start position:0% +cost okay that's true with any Market +structure margin re that's always profit + + align:start position:0% +structure margin re that's always profit + + + align:start position:0% +structure margin re that's always profit +maximizing well what's marginal marginal + + align:start position:0% +maximizing well what's marginal marginal + + + align:start position:0% +maximizing well what's marginal marginal +revenue here is 24 minus 2 + + align:start position:0% +revenue here is 24 minus 2 + + + align:start position:0% +revenue here is 24 minus 2 +Q marginal cost is 2 Q oh I should have + + align:start position:0% +Q marginal cost is 2 Q oh I should have + + + align:start position:0% +Q marginal cost is 2 Q oh I should have +made this a big Q well it doesn't matter + + align:start position:0% +made this a big Q well it doesn't matter + + + align:start position:0% +made this a big Q well it doesn't matter +right because little Q is Big q but to + + align:start position:0% +right because little Q is Big q but to + + + align:start position:0% +right because little Q is Big q but to +make life easier let's make that a big + + align:start position:0% +make life easier let's make that a big + + + align:start position:0% +make life easier let's make that a big +Q so what this says is that + + align:start position:0% +Q so what this says is that + + + align:start position:0% +Q so what this says is that +qar equal + + align:start position:0% +qar equal + + + align:start position:0% +qar equal +six that the optimal Monopoly quantity + + align:start position:0% +six that the optimal Monopoly quantity + + + align:start position:0% +six that the optimal Monopoly quantity +is + + align:start position:0% +is + + + align:start position:0% +is +six and how did I do this once again not + + align:start position:0% +six and how did I do this once again not + + + align:start position:0% +six and how did I do this once again not +too hard from the perspective of your + + align:start position:0% +too hard from the perspective of your + + + align:start position:0% +too hard from the perspective of your +aome math skills I simply took the + + align:start position:0% +aome math skills I simply took the + + + align:start position:0% +aome math skills I simply took the +demand curve created a revenue + + align:start position:0% +demand curve created a revenue + + + align:start position:0% +demand curve created a revenue +equation differentiated that to get + + align:start position:0% +equation differentiated that to get + + + align:start position:0% +equation differentiated that to get +marginal revenue have a cost equation + + align:start position:0% +marginal revenue have a cost equation + + + align:start position:0% +marginal revenue have a cost equation +differentiate that to get marginal cost + + align:start position:0% +differentiate that to get marginal cost + + + align:start position:0% +differentiate that to get marginal cost +set them equal and you get + + align:start position:0% +set them equal and you get + + + align:start position:0% +set them equal and you get +qar that's all you got to do + + align:start position:0% +qar that's all you got to do + + + align:start position:0% +qar that's all you got to do +okay now what is the + + align:start position:0% +okay now what is the + + + align:start position:0% +okay now what is the +price I solve for Q but it's not obvious + + align:start position:0% +price I solve for Q but it's not obvious + + + align:start position:0% +price I solve for Q but it's not obvious +here how you get back how do you get + + align:start position:0% + + + + align:start position:0% + +price so what's what's what's what price + + align:start position:0% +price so what's what's what's what price + + + align:start position:0% +price so what's what's what's what price +does the monopolis set + + align:start position:0% +does the monopolis set + + + align:start position:0% +does the monopolis set +yeah why + + align:start position:0% + + + + align:start position:0% + +18 exactly so you skip the usual thing + + align:start position:0% +18 exactly so you skip the usual thing + + + align:start position:0% +18 exactly so you skip the usual thing +where someone gives the wrong answer + + align:start position:0% +where someone gives the wrong answer + + + align:start position:0% +where someone gives the wrong answer +okay people often say well look Mar cost + + align:start position:0% +okay people often say well look Mar cost + + + align:start position:0% +okay people often say well look Mar cost +equals marginal revenue the quantity six + + align:start position:0% +equals marginal revenue the quantity six + + + align:start position:0% +equals marginal revenue the quantity six +and the price is + + align:start position:0% +and the price is + + + align:start position:0% +and the price is +12 that's the typical answer you say + + align:start position:0% +12 that's the typical answer you say + + + align:start position:0% +12 that's the typical answer you say +well look if marginal cost equals + + align:start position:0% +well look if marginal cost equals + + + align:start position:0% +well look if marginal cost equals +marginal revenue it's six then you go + + align:start position:0% +marginal revenue it's six then you go + + + align:start position:0% +marginal revenue it's six then you go +over to the y- axis and it's 12 and why + + align:start position:0% +over to the y- axis and it's 12 and why + + + align:start position:0% +over to the y- axis and it's 12 and why +is that wrong that's wrong because the + + align:start position:0% +is that wrong that's wrong because the + + + align:start position:0% +is that wrong that's wrong because the +monopolis still has to respect the + + align:start position:0% +monopolis still has to respect the + + + align:start position:0% +monopolis still has to respect the +demand curve anopolis cannot charge a + + align:start position:0% +demand curve anopolis cannot charge a + + + align:start position:0% +demand curve anopolis cannot charge a +price that people aren't willing to + + align:start position:0% +price that people aren't willing to + + + align:start position:0% +price that people aren't willing to +pay okay at a price of 12 that on on the + + align:start position:0% +pay okay at a price of 12 that on on the + + + align:start position:0% +pay okay at a price of 12 that on on the +demand curve people want way more at a + + align:start position:0% +demand curve people want way more at a + + + align:start position:0% +demand curve people want way more at a +price of 12 to be on the demand could to + + align:start position:0% +price of 12 to be on the demand could to + + + align:start position:0% +price of 12 to be on the demand could to +get to price we go back to the demand + + align:start position:0% +get to price we go back to the demand + + + align:start position:0% +get to price we go back to the demand +equation Q = 20 P = 24 minus Q well I + + align:start position:0% +equation Q = 20 P = 24 minus Q well I + + + align:start position:0% +equation Q = 20 P = 24 minus Q well I +just solved for qar so P + + align:start position:0% +just solved for qar so P + + + align:start position:0% +just solved for qar so P +staral 24 minus + + align:start position:0% +staral 24 minus + + + align:start position:0% +staral 24 minus +qar equals + + align:start position:0% +qar equals + + + align:start position:0% +qar equals +18 and this is where people get screwed + + align:start position:0% +18 and this is where people get screwed + + + align:start position:0% +18 and this is where people get screwed +up in the math here okay remember the + + align:start position:0% +up in the math here okay remember the + + + align:start position:0% +up in the math here okay remember the +monopolis has to respect the demand + + align:start position:0% +monopolis has to respect the demand + + + align:start position:0% +monopolis has to respect the demand +curve they're a price taker price maker + + align:start position:0% +curve they're a price taker price maker + + + align:start position:0% +curve they're a price taker price maker +I'm sorry but a price maker within the + + align:start position:0% +I'm sorry but a price maker within the + + + align:start position:0% +I'm sorry but a price maker within the +constraints the market gives them and + + align:start position:0% +constraints the market gives them and + + + align:start position:0% +constraints the market gives them and +the constraint the market gives them is + + align:start position:0% +the constraint the market gives them is + + + align:start position:0% +the constraint the market gives them is +the demain + + align:start position:0% +the demain + + + align:start position:0% +the demain +curve so basic so the the the um profit + + align:start position:0% +curve so basic so the the the um profit + + + align:start position:0% +curve so basic so the the the um profit +maximizing point is a price of 18 and + + align:start position:0% +maximizing point is a price of 18 and + + + align:start position:0% +maximizing point is a price of 18 and +selling six units and you could see at + + align:start position:0% +selling six units and you could see at + + + align:start position:0% +selling six units and you could see at +that point what are their profits well + + align:start position:0% +that point what are their profits well + + + align:start position:0% +that point what are their profits well +the profits are price minus average cost + + align:start position:0% +the profits are price minus average cost + + + align:start position:0% +the profits are price minus average cost +well at six units average cost is + + align:start position:0% +well at six units average cost is + + + align:start position:0% +well at six units average cost is +eight so they are making 10 per + + align:start position:0% +eight so they are making 10 per + + + align:start position:0% +eight so they are making 10 per +unit times six units is 60 and that's + + align:start position:0% +unit times six units is 60 and that's + + + align:start position:0% +unit times six units is 60 and that's +their profits + + align:start position:0% +their profits + + + align:start position:0% +their profits +now you might say + + align:start position:0% +now you might say + + + align:start position:0% +now you might say +gee consumers are willing to buy a lot + + align:start position:0% +gee consumers are willing to buy a lot + + + align:start position:0% +gee consumers are willing to buy a lot +more units think about think about the + + align:start position:0% +more units think about think about the + + + align:start position:0% +more units think about think about the +seventh + + align:start position:0% +seventh + + + align:start position:0% +seventh +unit say the seventh unit well this is + + align:start position:0% +unit say the seventh unit well this is + + + align:start position:0% +unit say the seventh unit well this is +what's weird to me if you look at the + + align:start position:0% +what's weird to me if you look at the + + + align:start position:0% +what's weird to me if you look at the +seventh unit demand is above + + align:start position:0% +seventh unit demand is above + + + align:start position:0% +seventh unit demand is above +cost consumer's willingness to + + align:start position:0% +cost consumer's willingness to + + + align:start position:0% +cost consumer's willingness to +pay at the seventh unit is seven I'm + + align:start position:0% +pay at the seventh unit is seven I'm + + + align:start position:0% +pay at the seventh unit is seven I'm +sorry 17 right if you had a price if you + + align:start position:0% +sorry 17 right if you had a price if you + + + align:start position:0% +sorry 17 right if you had a price if you +had a price of seven + + align:start position:0% +had a price of seven + + + align:start position:0% +had a price of seven +uh I'm sorry if you want to sell seven + + align:start position:0% +uh I'm sorry if you want to sell seven + + + align:start position:0% +uh I'm sorry if you want to sell seven +units consumer willing to pay + + align:start position:0% +units consumer willing to pay + + + align:start position:0% +units consumer willing to pay +17 and what's the marginal cost at seven + + align:start position:0% +17 and what's the marginal cost at seven + + + align:start position:0% +17 and what's the marginal cost at seven +units well it's + + align:start position:0% +units well it's + + + align:start position:0% +units well it's +14 so this is weird marginal revenue I'm + + align:start position:0% +14 so this is weird marginal revenue I'm + + + align:start position:0% +14 so this is weird marginal revenue I'm +sorry + + align:start position:0% +sorry + + + align:start position:0% +sorry +price exceeds marginal cost so why don't + + align:start position:0% +price exceeds marginal cost so why don't + + + align:start position:0% +price exceeds marginal cost so why don't +they produce that seventh unit because + + align:start position:0% +they produce that seventh unit because + + + align:start position:0% +they produce that seventh unit because +of the poisoning + + align:start position:0% +of the poisoning + + + align:start position:0% +of the poisoning +effect to produce that seventh unit + + align:start position:0% +effect to produce that seventh unit + + + align:start position:0% +effect to produce that seventh unit +they'd have to lower the price to 17 to + + align:start position:0% +they'd have to lower the price to 17 to + + + align:start position:0% +they'd have to lower the price to 17 to +sell it not to to produce it to sell it + + align:start position:0% +sell it not to to produce it to sell it + + + align:start position:0% +sell it not to to produce it to sell it +lower price 17 they lower price 17 they + + align:start position:0% +lower price 17 they lower price 17 they + + + align:start position:0% +lower price 17 they lower price 17 they +make less money on the first six + + align:start position:0% +make less money on the first six + + + align:start position:0% +make less money on the first six +units indeed what are their profits if + + align:start position:0% +units indeed what are their profits if + + + align:start position:0% +units indeed what are their profits if +they sell seven well if they sell seven + + align:start position:0% +they sell seven well if they sell seven + + + align:start position:0% +they sell seven well if they sell seven +units what are their profits well they + + align:start position:0% +units what are their profits well they + + + align:start position:0% +units what are their profits well they +sell seven units profits equal seven + + align:start position:0% +sell seven units profits equal seven + + + align:start position:0% +sell seven units profits equal seven +units at a price of 17 minus costs what + + align:start position:0% +units at a price of 17 minus costs what + + + align:start position:0% +units at a price of 17 minus costs what +are their costs if they're producing + + align:start position:0% +are their costs if they're producing + + + align:start position:0% +are their costs if they're producing +seventh units well it's 12 + 7 squared + + align:start position:0% +seventh units well it's 12 + 7 squared + + + align:start position:0% +seventh units well it's 12 + 7 squared +so it's 12 + 7 squared uh so that's uh + + align:start position:0% +so it's 12 + 7 squared uh so that's uh + + + align:start position:0% +so it's 12 + 7 squared uh so that's uh +12 + + + align:start position:0% + + + + align:start position:0% + +49 and if you do the math you get + + align:start position:0% +49 and if you do the math you get + + + align:start position:0% +49 and if you do the math you get +profits are + + align:start position:0% + + + + align:start position:0% + +58 they get lower profits selling seven + + align:start position:0% +58 they get lower profits selling seven + + + align:start position:0% +58 they get lower profits selling seven +units this is crazy think about this we + + align:start position:0% +units this is crazy think about this we + + + align:start position:0% +units this is crazy think about this we +have units where people are willing to + + align:start position:0% +have units where people are willing to + + + align:start position:0% +have units where people are willing to +pay more than it costs to produce and + + align:start position:0% +pay more than it costs to produce and + + + align:start position:0% +pay more than it costs to produce and +yet to sell them monopolis will actually + + align:start position:0% +yet to sell them monopolis will actually + + + align:start position:0% +yet to sell them monopolis will actually +lower their + + align:start position:0% +lower their + + + align:start position:0% +lower their +profits That's The Power of this + + align:start position:0% +profits That's The Power of this + + + align:start position:0% +profits That's The Power of this +poisoning effect effect the reason lower + + align:start position:0% +poisoning effect effect the reason lower + + + align:start position:0% +poisoning effect effect the reason lower +their profits because they they can make + + align:start position:0% +their profits because they they can make + + + align:start position:0% +their profits because they they can make +more money by selling less at a higher + + align:start position:0% +more money by selling less at a higher + + + align:start position:0% +more money by selling less at a higher +price + + align:start position:0% + + + + align:start position:0% + +yeah what I said they can't do that I + + align:start position:0% +yeah what I said they can't do that I + + + align:start position:0% +yeah what I said they can't do that I +just ruled that out we're going to come + + align:start position:0% +just ruled that out we're going to come + + + align:start position:0% +just ruled that out we're going to come +back to that but that's the key is don't + + align:start position:0% +back to that but that's the key is don't + + + align:start position:0% +back to that but that's the key is don't +the way I describe it is the way you + + align:start position:0% +the way I describe it is the way you + + + align:start position:0% +the way I describe it is the way you +think of the decision- making don't + + align:start position:0% +think of the decision- making don't + + + align:start position:0% +think of the decision- making don't +think of them saying I'm gon to set this + + align:start position:0% +think of them saying I'm gon to set this + + + align:start position:0% +think of them saying I'm gon to set this +for this just think I want to sell X + + align:start position:0% +for this just think I want to sell X + + + align:start position:0% +for this just think I want to sell X +units what do I have to charge so + + align:start position:0% +units what do I have to charge so + + + align:start position:0% +units what do I have to charge so +they're sitting back saying how many + + align:start position:0% +they're sitting back saying how many + + + align:start position:0% +they're sitting back saying how many +units should I produce well if I produce + + align:start position:0% +units should I produce well if I produce + + + align:start position:0% +units should I produce well if I produce +six I can sell for 18 I make 60 if I + + align:start position:0% +six I can sell for 18 I make 60 if I + + + align:start position:0% +six I can sell for 18 I make 60 if I +produce seven I sell for 17 I make 58 + + align:start position:0% +produce seven I sell for 17 I make 58 + + + align:start position:0% +produce seven I sell for 17 I make 58 +I'm going to produce six that's the way + + align:start position:0% +I'm going to produce six that's the way + + + align:start position:0% +I'm going to produce six that's the way +they think about it okay so that is the + + align:start position:0% +they think about it okay so that is the + + + align:start position:0% +they think about it okay so that is the +power here now what does this + + align:start position:0% +power here now what does this + + + align:start position:0% +power here now what does this +mean this means that monopolists because + + align:start position:0% +mean this means that monopolists because + + + align:start position:0% +mean this means that monopolists because +they can set price have something we + + align:start position:0% +they can set price have something we + + + align:start position:0% +they can set price have something we +call Market + + align:start position:0% + + + + align:start position:0% + +power monopolists have Market power what + + align:start position:0% +power monopolists have Market power what + + + align:start position:0% +power monopolists have Market power what +do I mean by + + align:start position:0% +do I mean by + + + align:start position:0% +do I mean by +that market power means that basically + + align:start position:0% +that market power means that basically + + + align:start position:0% +that market power means that basically +monopolists can make money even in the + + align:start position:0% +monopolists can make money even in the + + + align:start position:0% +monopolists can make money even in the +long run to see this let's think about + + align:start position:0% +long run to see this let's think about + + + align:start position:0% +long run to see this let's think about +um the marginal revenue expression so + + align:start position:0% +um the marginal revenue expression so + + + align:start position:0% +um the marginal revenue expression so +marginal + + align:start position:0% +marginal + + + align:start position:0% +marginal +revenue okay marginal + + align:start position:0% +revenue okay marginal + + + align:start position:0% +revenue okay marginal +revenue equals + + align:start position:0% +revenue equals + + + align:start position:0% +revenue equals +p+ DP DQ * Q + + align:start position:0% +p+ DP DQ * Q + + + align:start position:0% +p+ DP DQ * Q +now take that + + align:start position:0% +now take that + + + align:start position:0% +now take that +equation and multip and take the uh + + align:start position:0% +equation and multip and take the uh + + + align:start position:0% +equation and multip and take the uh +second term and multiply and divide by + + align:start position:0% +second term and multiply and divide by + + + align:start position:0% +second term and multiply and divide by +price so I want to take the second term + + align:start position:0% +price so I want to take the second term + + + align:start position:0% +price so I want to take the second term +I want to rewrite as P + + align:start position:0% +I want to rewrite as P + + + align:start position:0% +I want to rewrite as P +plus + + align:start position:0% +plus + + + align:start position:0% +plus +DP + + align:start position:0% +DP + + + align:start position:0% +DP +DQ time Q over P * p i just multiply and + + align:start position:0% +DQ time Q over P * p i just multiply and + + + align:start position:0% +DQ time Q over P * p i just multiply and +divide it by + + align:start position:0% +divide it by + + + align:start position:0% +divide it by +price it's all I + + align:start position:0% +price it's all I + + + align:start position:0% +price it's all I +did can anyone tell + + align:start position:0% +did can anyone tell + + + align:start position:0% +did can anyone tell +me what this term looks + + align:start position:0% +me what this term looks + + + align:start position:0% +me what this term looks +like + + align:start position:0% +like + + + align:start position:0% +like +yeah the elasticity of demand but + + align:start position:0% +yeah the elasticity of demand but + + + align:start position:0% +yeah the elasticity of demand but +inverted this is the inverse of price + + align:start position:0% +inverted this is the inverse of price + + + align:start position:0% +inverted this is the inverse of price +elicity demand so I can rewrite marginal + + align:start position:0% +elicity demand so I can rewrite marginal + + + align:start position:0% +elicity demand so I can rewrite marginal +revenue I can rewrite marginal + + align:start position:0% +revenue I can rewrite marginal + + + align:start position:0% +revenue I can rewrite marginal +revenue as P * 1 + one over the + + align:start position:0% +revenue as P * 1 + one over the + + + align:start position:0% +revenue as P * 1 + one over the +elasticity of + + align:start position:0% + + + + align:start position:0% + +demand okay all I did no trick here I + + align:start position:0% +demand okay all I did no trick here I + + + align:start position:0% +demand okay all I did no trick here I +just well there's a little math trick + + align:start position:0% +just well there's a little math trick + + + align:start position:0% +just well there's a little math trick +rote margin Revenue multiply and divide + + align:start position:0% +rote margin Revenue multiply and divide + + + align:start position:0% +rote margin Revenue multiply and divide +the second term by P kept the first + + align:start position:0% +the second term by P kept the first + + + align:start position:0% +the second term by P kept the first +term then realize this is the inverse + + align:start position:0% +term then realize this is the inverse + + + align:start position:0% +term then realize this is the inverse +the elasticity of demand so I can write + + align:start position:0% +the elasticity of demand so I can write + + + align:start position:0% +the elasticity of demand so I can write +margin Revenue as P * 1 plus the inverse + + align:start position:0% +margin Revenue as P * 1 plus the inverse + + + align:start position:0% +margin Revenue as P * 1 plus the inverse +the elasticity of + + align:start position:0% + + + + align:start position:0% + +demand okay why is this + + align:start position:0% +demand okay why is this + + + align:start position:0% +demand okay why is this +important because what this says is the + + align:start position:0% +important because what this says is the + + + align:start position:0% +important because what this says is the +amount the ability of monopolis to make + + align:start position:0% +amount the ability of monopolis to make + + + align:start position:0% +amount the ability of monopolis to make +money depends on how elastic is the + + align:start position:0% +money depends on how elastic is the + + + align:start position:0% +money depends on how elastic is the +demand they + + align:start position:0% +demand they + + + align:start position:0% +demand they +face okay so what would happen here if + + align:start position:0% +face okay so what would happen here if + + + align:start position:0% +face okay so what would happen here if +the elasticity demand was negative + + align:start position:0% +the elasticity demand was negative + + + align:start position:0% +the elasticity demand was negative +Infinity what would marginal revenue + + align:start position:0% + + + + align:start position:0% + +be if the is negative Infinity what + + align:start position:0% +be if the is negative Infinity what + + + align:start position:0% +be if the is negative Infinity what +marginal revenue + + align:start position:0% +marginal revenue + + + align:start position:0% +marginal revenue +be come on you guys your MIT students + + align:start position:0% +be come on you guys your MIT students + + + align:start position:0% +be come on you guys your MIT students +don't be shy raise your + + align:start position:0% +don't be shy raise your + + + align:start position:0% +don't be shy raise your +hand yeah P what does that sound like + + align:start position:0% +hand yeah P what does that sound like + + + align:start position:0% +hand yeah P what does that sound like +margin REM equals P we've heard that + + align:start position:0% +margin REM equals P we've heard that + + + align:start position:0% +margin REM equals P we've heard that +before that's the perfectly competitive + + align:start position:0% +before that's the perfectly competitive + + + align:start position:0% +before that's the perfectly competitive +case well perfectly competitive case + + align:start position:0% +case well perfectly competitive case + + + align:start position:0% +case well perfectly competitive case +firms face perfectly elastic demand so + + align:start position:0% +firms face perfectly elastic demand so + + + align:start position:0% +firms face perfectly elastic demand so +if demand in the market was perfectly + + align:start position:0% +if demand in the market was perfectly + + + align:start position:0% +if demand in the market was perfectly +elastic monopolis would behave just like + + align:start position:0% +elastic monopolis would behave just like + + + align:start position:0% +elastic monopolis would behave just like +perfectly competitive + + align:start position:0% +perfectly competitive + + + align:start position:0% +perfectly competitive +firms okay on the other hand as the + + align:start position:0% +firms okay on the other hand as the + + + align:start position:0% +firms okay on the other hand as the +elasticity Falls or Rises or Falls at + + align:start position:0% +elasticity Falls or Rises or Falls at + + + align:start position:0% +elasticity Falls or Rises or Falls at +absolute value but rises from Nega 50 + + align:start position:0% +absolute value but rises from Nega 50 + + + align:start position:0% +absolute value but rises from Nega 50 +towards zero monopolists start to be + + align:start position:0% +towards zero monopolists start to be + + + align:start position:0% +towards zero monopolists start to be +able to charge more than monopolis start + + align:start position:0% +able to charge more than monopolis start + + + align:start position:0% +able to charge more than monopolis start +tab marginal revenue above the + + align:start position:0% +tab marginal revenue above the + + + align:start position:0% +tab marginal revenue above the +price okay monopolis start tab marginal + + align:start position:0% +price okay monopolis start tab marginal + + + align:start position:0% +price okay monopolis start tab marginal +revenue above the price okay so we can + + align:start position:0% +revenue above the price okay so we can + + + align:start position:0% +revenue above the price okay so we can +rewrite this let's rewrite the condition + + align:start position:0% +rewrite this let's rewrite the condition + + + align:start position:0% +rewrite this let's rewrite the condition +for profit maximization profit + + align:start position:0% +for profit maximization profit + + + align:start position:0% +for profit maximization profit +maximization is that marginal revenue + + align:start position:0% +maximization is that marginal revenue + + + align:start position:0% +maximization is that marginal revenue +which equals P * 1 + 1 over the Allis + + align:start position:0% +which equals P * 1 + 1 over the Allis + + + align:start position:0% +which equals P * 1 + 1 over the Allis +demand equals marginal + + align:start position:0% +demand equals marginal + + + align:start position:0% +demand equals marginal +cost okay that's our profit maximizing + + align:start position:0% +cost okay that's our profit maximizing + + + align:start position:0% +cost okay that's our profit maximizing +condition okay so in other words we can + + align:start position:0% +condition okay so in other words we can + + + align:start position:0% +condition okay so in other words we can +write that marginal cost over price + + align:start position:0% +write that marginal cost over price + + + align:start position:0% +write that marginal cost over price +equals + + align:start position:0% +equals + + + align:start position:0% +equals +1 + 1 + + align:start position:0% +1 + 1 + + + align:start position:0% +1 + 1 +Epsilon marginal cost over price equals + + align:start position:0% +Epsilon marginal cost over price equals + + + align:start position:0% +Epsilon marginal cost over price equals +1 plus uh 1 plus 1 over Epsilon now + + align:start position:0% +1 plus uh 1 plus 1 over Epsilon now + + + align:start position:0% +1 plus uh 1 plus 1 over Epsilon now +let's define something I'm going to call + + align:start position:0% +let's define something I'm going to call + + + align:start position:0% +let's define something I'm going to call +the + + align:start position:0% +the + + + align:start position:0% +the +markup the markup is how much more + + align:start position:0% +markup the markup is how much more + + + align:start position:0% +markup the markup is how much more +monopolis can charge in perfectly + + align:start position:0% +monopolis can charge in perfectly + + + align:start position:0% +monopolis can charge in perfectly +competitive firms I'm going to find the + + align:start position:0% +competitive firms I'm going to find the + + + align:start position:0% +competitive firms I'm going to find the +markup as P minus MC over P that's what + + align:start position:0% +markup as P minus MC over P that's what + + + align:start position:0% +markup as P minus MC over P that's what +we call the + + align:start position:0% +we call the + + + align:start position:0% +we call the +markup that is how much more can + + align:start position:0% +markup that is how much more can + + + align:start position:0% +markup that is how much more can +monopolis charge than competitive firms + + align:start position:0% +monopolis charge than competitive firms + + + align:start position:0% +monopolis charge than competitive firms +it's the markup well the answer is equal + + align:start position:0% +it's the markup well the answer is equal + + + align:start position:0% +it's the markup well the answer is equal +to if we do the math the answer is equal + + align:start position:0% +to if we do the math the answer is equal + + + align:start position:0% +to if we do the math the answer is equal +to minus one over the elasticity of + + align:start position:0% +to minus one over the elasticity of + + + align:start position:0% +to minus one over the elasticity of +demand if you do the math the markup is + + align:start position:0% +demand if you do the math the markup is + + + align:start position:0% +demand if you do the math the markup is +minus one over thees demand in other + + align:start position:0% +minus one over thees demand in other + + + align:start position:0% +minus one over thees demand in other +words the profits monopolis can make are + + align:start position:0% +words the profits monopolis can make are + + + align:start position:0% +words the profits monopolis can make are +inversely proportional to the elasticity + + align:start position:0% +inversely proportional to the elasticity + + + align:start position:0% +inversely proportional to the elasticity +of + + align:start position:0% +of + + + align:start position:0% +of +demand why does that make + + align:start position:0% +demand why does that make + + + align:start position:0% +demand why does that make +sense why does it makes sense that the + + align:start position:0% +sense why does it makes sense that the + + + align:start position:0% +sense why does it makes sense that the +elastic demand as markets get more in + + align:start position:0% +elastic demand as markets get more in + + + align:start position:0% +elastic demand as markets get more in +elastic monopolis make more money as + + align:start position:0% +elastic monopolis make more money as + + + align:start position:0% +elastic monopolis make more money as +markets get more elastic monopolis make + + align:start position:0% +markets get more elastic monopolis make + + + align:start position:0% +markets get more elastic monopolis make +less + + align:start position:0% +less + + + align:start position:0% +less +money why does that make + + align:start position:0% +money why does that make + + + align:start position:0% +money why does that make +sense + + align:start position:0% + + + + align:start position:0% + +yeah yeah insulin the perfectly in + + align:start position:0% +yeah yeah insulin the perfectly in + + + align:start position:0% +yeah yeah insulin the perfectly in +elastic + + align:start position:0% + + + + align:start position:0% + +good exactly you have to buy it so given + + align:start position:0% +good exactly you have to buy it so given + + + align:start position:0% +good exactly you have to buy it so given +that they can charge ever the hell they + + align:start position:0% +that they can charge ever the hell they + + + align:start position:0% +that they can charge ever the hell they +want this is the answer to the question + + align:start position:0% +want this is the answer to the question + + + align:start position:0% +want this is the answer to the question +you might have first thought or some + + align:start position:0% +you might have first thought or some + + + align:start position:0% +you might have first thought or some +might think is well gee if a firm's a + + align:start position:0% +might think is well gee if a firm's a + + + align:start position:0% +might think is well gee if a firm's a +monopoly why don't they just charge + + align:start position:0% +monopoly why don't they just charge + + + align:start position:0% +monopoly why don't they just charge +whatever they want why do monopolists + + align:start position:0% +whatever they want why do monopolists + + + align:start position:0% +whatever they want why do monopolists +have to with they're price makers + + align:start position:0% +have to with they're price makers + + + align:start position:0% +have to with they're price makers +they're the only game in town why don't + + align:start position:0% +they're the only game in town why don't + + + align:start position:0% +they're the only game in town why don't +they just charge whatever the hell they + + align:start position:0% +they just charge whatever the hell they + + + align:start position:0% +they just charge whatever the hell they +want and the answer is because while + + align:start position:0% +want and the answer is because while + + + align:start position:0% +want and the answer is because while +people can't substitute to other firms + + align:start position:0% +people can't substitute to other firms + + + align:start position:0% +people can't substitute to other firms +they can substitute to other + + align:start position:0% +they can substitute to other + + + align:start position:0% +they can substitute to other +Goods so if it's a good if you're + + align:start position:0% +Goods so if it's a good if you're + + + align:start position:0% +Goods so if it's a good if you're +monopolizing a good with there's very + + align:start position:0% +monopolizing a good with there's very + + + align:start position:0% +monopolizing a good with there's very +good substitutes and you try to charge a + + align:start position:0% +good substitutes and you try to charge a + + + align:start position:0% +good substitutes and you try to charge a +very high price they'll just switch to + + align:start position:0% +very high price they'll just switch to + + + align:start position:0% +very high price they'll just switch to +the The + + align:start position:0% +the The + + + align:start position:0% +the The +Substitute so if the elastic demand is + + align:start position:0% +Substitute so if the elastic demand is + + + align:start position:0% +Substitute so if the elastic demand is +very large a large negative number they + + align:start position:0% +very large a large negative number they + + + align:start position:0% +very large a large negative number they +can't make much profit sure they're the + + align:start position:0% +can't make much profit sure they're the + + + align:start position:0% +can't make much profit sure they're the +only firm but if they're the only firm + + align:start position:0% +only firm but if they're the only firm + + + align:start position:0% +only firm but if they're the only firm +making spearmint gum and people are + + align:start position:0% +making spearmint gum and people are + + + align:start position:0% +making spearmint gum and people are +pretty different between spearmint gum + + align:start position:0% +pretty different between spearmint gum + + + align:start position:0% +pretty different between spearmint gum +and peppermint gum they can't charge + + align:start position:0% +and peppermint gum they can't charge + + + align:start position:0% +and peppermint gum they can't charge +outrageously high prices because people + + align:start position:0% +outrageously high prices because people + + + align:start position:0% +outrageously high prices because people +just switch to peppermint gum but if + + align:start position:0% +just switch to peppermint gum but if + + + align:start position:0% +just switch to peppermint gum but if +they're the only firm making insulin + + align:start position:0% +they're the only firm making insulin + + + align:start position:0% +they're the only firm making insulin +then they can charge an outrageously + + align:start position:0% +then they can charge an outrageously + + + align:start position:0% +then they can charge an outrageously +high price because there's nowhere to + + align:start position:0% +high price because there's nowhere to + + + align:start position:0% +high price because there's nowhere to +go so the money monopolis make monopolis + + align:start position:0% +go so the money monopolis make monopolis + + + align:start position:0% +go so the money monopolis make monopolis +in a perfect competitive market firms + + align:start position:0% +in a perfect competitive market firms + + + align:start position:0% +in a perfect competitive market firms +are disciplined by competition from + + align:start position:0% +are disciplined by competition from + + + align:start position:0% +are disciplined by competition from +other firms in a monopoly Market firms + + align:start position:0% +other firms in a monopoly Market firms + + + align:start position:0% +other firms in a monopoly Market firms +are disciplined only by the elasticity + + align:start position:0% +are disciplined only by the elasticity + + + align:start position:0% +are disciplined only by the elasticity +of demand that's the only disciplining + + align:start position:0% +of demand that's the only disciplining + + + align:start position:0% +of demand that's the only disciplining +effect on the + + align:start position:0% +effect on the + + + align:start position:0% +effect on the +firm okay so let's do a simple example + + align:start position:0% +firm okay so let's do a simple example + + + align:start position:0% +firm okay so let's do a simple example +two books you guys probably had to read + + align:start position:0% +two books you guys probably had to read + + + align:start position:0% +two books you guys probably had to read +in high school Huckleberry thin and + + align:start position:0% +in high school Huckleberry thin and + + + align:start position:0% +in high school Huckleberry thin and +Fahrenheit + + align:start position:0% +Fahrenheit + + + align:start position:0% +Fahrenheit +451 if you go on Amazon right now you + + align:start position:0% +451 if you go on Amazon right now you + + + align:start position:0% +451 if you go on Amazon right now you +can get Huckleberry fin for about four + + align:start position:0% +can get Huckleberry fin for about four + + + align:start position:0% +can get Huckleberry fin for about four +bucks in paperback or zero on + + align:start position:0% +bucks in paperback or zero on + + + align:start position:0% +bucks in paperback or zero on +Kindle uh fahren 451 is about n bucks + + align:start position:0% +Kindle uh fahren 451 is about n bucks + + + align:start position:0% +Kindle uh fahren 451 is about n bucks +and about the same on + + align:start position:0% +and about the same on + + + align:start position:0% +and about the same on +Kindle why they're both twoo old books + + align:start position:0% +Kindle why they're both twoo old books + + + align:start position:0% +Kindle why they're both twoo old books +people have to basically read them about + + align:start position:0% +people have to basically read them about + + + align:start position:0% +people have to basically read them about +the same they're all high school + + align:start position:0% +the same they're all high school + + + align:start position:0% +the same they're all high school +required books the marginal cost of + + align:start position:0% +required books the marginal cost of + + + align:start position:0% +required books the marginal cost of +production can't be that + + align:start position:0% +production can't be that + + + align:start position:0% +production can't be that +different of producing Fahrenheit for + + align:start position:0% +different of producing Fahrenheit for + + + align:start position:0% +different of producing Fahrenheit for +they're they're slightly different + + align:start position:0% +they're they're slightly different + + + align:start position:0% +they're they're slightly different +lengths but not that different certainly + + align:start position:0% +lengths but not that different certainly + + + align:start position:0% +lengths but not that different certainly +un Kindle the marginal cost of + + align:start position:0% +un Kindle the marginal cost of + + + align:start position:0% +un Kindle the marginal cost of +Productions comparable so why why is + + align:start position:0% +Productions comparable so why why is + + + align:start position:0% +Productions comparable so why why is +Fahrenheit 451 so much more expensive + + align:start position:0% +Fahrenheit 451 so much more expensive + + + align:start position:0% +Fahrenheit 451 so much more expensive +than Huckleberry Finn + + align:start position:0% + + + + align:start position:0% + +do anyone + + align:start position:0% +do anyone + + + align:start position:0% +do anyone +know go ahead you have an idea any + + align:start position:0% +know go ahead you have an idea any + + + align:start position:0% +know go ahead you have an idea any +thoughts okay well the reason is because + + align:start position:0% +thoughts okay well the reason is because + + + align:start position:0% +thoughts okay well the reason is because +in the US oh yeah go + + align:start position:0% + + + + align:start position:0% + +ahead exactly in the US we have + + align:start position:0% +ahead exactly in the US we have + + + align:start position:0% +ahead exactly in the US we have +something called copyright laws which + + align:start position:0% +something called copyright laws which + + + align:start position:0% +something called copyright laws which +say that for 75 years after the author's + + align:start position:0% +say that for 75 years after the author's + + + align:start position:0% +say that for 75 years after the author's +death only the author or his estate or + + align:start position:0% +death only the author or his estate or + + + align:start position:0% +death only the author or his estate or +her estate can approve production of the + + align:start position:0% +her estate can approve production of the + + + align:start position:0% +her estate can approve production of the +book which gives them a monopoly Mark + + align:start position:0% +book which gives them a monopoly Mark + + + align:start position:0% +book which gives them a monopoly Mark +Twain died more than 75 years ago Ray + + align:start position:0% +Twain died more than 75 years ago Ray + + + align:start position:0% +Twain died more than 75 years ago Ray +Bradberry did not so as a result there's + + align:start position:0% +Bradberry did not so as a result there's + + + align:start position:0% +Bradberry did not so as a result there's +no more Monopoly anybody with a printing + + align:start position:0% +no more Monopoly anybody with a printing + + + align:start position:0% +no more Monopoly anybody with a printing +press or whatever it is to make an ebook + + align:start position:0% +press or whatever it is to make an ebook + + + align:start position:0% +press or whatever it is to make an ebook +I don't know how you do that can make a + + align:start position:0% +I don't know how you do that can make a + + + align:start position:0% +I don't know how you do that can make a +copy Huckleberry + + align:start position:0% +copy Huckleberry + + + align:start position:0% +copy Huckleberry +Finn so it's perfectly + + align:start position:0% +Finn so it's perfectly + + + align:start position:0% +Finn so it's perfectly +competitive okay and so profits get + + align:start position:0% +competitive okay and so profits get + + + align:start position:0% +competitive okay and so profits get +driven to zero but fite 451 they still + + align:start position:0% +driven to zero but fite 451 they still + + + align:start position:0% +driven to zero but fite 451 they still +have a monopoly right so they're making + + align:start position:0% +have a monopoly right so they're making + + + align:start position:0% +have a monopoly right so they're making +profits now why is 451 everyone has to + + align:start position:0% +profits now why is 451 everyone has to + + + align:start position:0% +profits now why is 451 everyone has to +read Fahrenheit 451 why don't they + + align:start position:0% +read Fahrenheit 451 why don't they + + + align:start position:0% +read Fahrenheit 451 why don't they +charge a 100 bucks because then high + + align:start position:0% +charge a 100 bucks because then high + + + align:start position:0% +charge a 100 bucks because then high +schools say you know what Fahrenheit 451 + + align:start position:0% +schools say you know what Fahrenheit 451 + + + align:start position:0% +schools say you know what Fahrenheit 451 +is fine but you know there's other ones + + align:start position:0% +is fine but you know there's other ones + + + align:start position:0% +is fine but you know there's other ones +that are okay + + align:start position:0% +that are okay + + + align:start position:0% +that are okay +too so there's some eless this demand + + align:start position:0% +too so there's some eless this demand + + + align:start position:0% +too so there's some eless this demand +disciplining the market for Fahrenheit + + align:start position:0% +disciplining the market for Fahrenheit + + + align:start position:0% +disciplining the market for Fahrenheit +451 but it's not as much as disciplin + + align:start position:0% +451 but it's not as much as disciplin + + + align:start position:0% +451 but it's not as much as disciplin +the market for Huckleberry fin okay + + align:start position:0% +the market for Huckleberry fin okay + + + align:start position:0% +the market for Huckleberry fin okay +questions about + + align:start position:0% +questions about + + + align:start position:0% +questions about +that okay let's go on then and talk + + align:start position:0% +that okay let's go on then and talk + + + align:start position:0% +that okay let's go on then and talk +about the welfare effects of Monopoly + + align:start position:0% + + + + align:start position:0% + +because now we have the tools in this + + align:start position:0% +because now we have the tools in this + + + align:start position:0% +because now we have the tools in this +class to move Beyond positive economics + + align:start position:0% +class to move Beyond positive economics + + + align:start position:0% +class to move Beyond positive economics +talk about normative + + align:start position:0% +talk about normative + + + align:start position:0% +talk about normative +economics and we have the tools to show + + align:start position:0% +economics and we have the tools to show + + + align:start position:0% +economics and we have the tools to show +you that Monopoly causes our first + + align:start position:0% +you that Monopoly causes our first + + + align:start position:0% +you that Monopoly causes our first +example what we call a market + + align:start position:0% +example what we call a market + + + align:start position:0% +example what we call a market +failure let's look at figure + + align:start position:0% +failure let's look at figure + + + align:start position:0% +failure let's look at figure +115 back to the example we used the + + align:start position:0% +115 back to the example we used the + + + align:start position:0% +115 back to the example we used the +domain curve is 24 minus Q the marginal + + align:start position:0% +domain curve is 24 minus Q the marginal + + + align:start position:0% +domain curve is 24 minus Q the marginal +cost is 2 Q same example we were just + + align:start position:0% +cost is 2 Q same example we were just + + + align:start position:0% +cost is 2 Q same example we were just +using the monopolis sells six units at a + + align:start position:0% +using the monopolis sells six units at a + + + align:start position:0% +using the monopolis sells six units at a +price of + + align:start position:0% +price of + + + align:start position:0% +price of +18 okay the competitive + + align:start position:0% +18 okay the competitive + + + align:start position:0% +18 okay the competitive +equilibrium would be eight units at a + + align:start position:0% +equilibrium would be eight units at a + + + align:start position:0% +equilibrium would be eight units at a +price of + + align:start position:0% +price of + + + align:start position:0% +price of +16 how do we know this well we just said + + align:start position:0% +16 how do we know this well we just said + + + align:start position:0% +16 how do we know this well we just said +price equal the marginal cost marginal + + align:start position:0% +price equal the marginal cost marginal + + + align:start position:0% +price equal the marginal cost marginal +cost equals 2 Q so that would be true at + + align:start position:0% +cost equals 2 Q so that would be true at + + + align:start position:0% +cost equals 2 Q so that would be true at +qal 8 p equal 16 we all could see it + + align:start position:0% +qal 8 p equal 16 we all could see it + + + align:start position:0% +qal 8 p equal 16 we all could see it +from the intersection the demand Supply + + align:start position:0% +from the intersection the demand Supply + + + align:start position:0% +from the intersection the demand Supply +curves so the competitive case they sell + + align:start position:0% +curves so the competitive case they sell + + + align:start position:0% +curves so the competitive case they sell +eight units at a price of 16 the + + align:start position:0% +eight units at a price of 16 the + + + align:start position:0% +eight units at a price of 16 the +Monopoly case they sell six units at a + + align:start position:0% +Monopoly case they sell six units at a + + + align:start position:0% +Monopoly case they sell six units at a +price of + + align:start position:0% +price of + + + align:start position:0% +price of +18 what is the consumer surplus in the + + align:start position:0% +18 what is the consumer surplus in the + + + align:start position:0% +18 what is the consumer surplus in the +competitive case what letters represent + + align:start position:0% +competitive case what letters represent + + + align:start position:0% +competitive case what letters represent +the consumer surplus in the competitive + + align:start position:0% +the consumer surplus in the competitive + + + align:start position:0% +the consumer surplus in the competitive +case at Point + + align:start position:0% +case at Point + + + align:start position:0% +case at Point +EC don't raise their hand and tell + + align:start position:0% +EC don't raise their hand and tell + + + align:start position:0% +EC don't raise their hand and tell +me come on guys help me out here yeah + + align:start position:0% +me come on guys help me out here yeah + + + align:start position:0% +me come on guys help me out here yeah +loud + + align:start position:0% +loud + + + align:start position:0% +loud +loud a plus b plus + + align:start position:0% +loud a plus b plus + + + align:start position:0% +loud a plus b plus +C same person what's the producer + + align:start position:0% +C same person what's the producer + + + align:start position:0% +C same person what's the producer +Surplus in competitive + + align:start position:0% +Surplus in competitive + + + align:start position:0% +Surplus in competitive +case D plus e now now in the Monopoly + + align:start position:0% +case D plus e now now in the Monopoly + + + align:start position:0% +case D plus e now now in the Monopoly +case what has happened to consumer + + align:start position:0% +case what has happened to consumer + + + align:start position:0% +case what has happened to consumer +surplus it has fallen from a plus b plus + + align:start position:0% +surplus it has fallen from a plus b plus + + + align:start position:0% +surplus it has fallen from a plus b plus +C to just a so consumer + + align:start position:0% +C to just a so consumer + + + align:start position:0% +C to just a so consumer +surplus from the competitive case to + + align:start position:0% +surplus from the competitive case to + + + align:start position:0% +surplus from the competitive case to +Monopoly case has gone from a plus b + + align:start position:0% +Monopoly case has gone from a plus b + + + align:start position:0% +Monopoly case has gone from a plus b +plus C to just + + align:start position:0% +plus C to just + + + align:start position:0% +plus C to just +a what about producer Surplus producer + + align:start position:0% +a what about producer Surplus producer + + + align:start position:0% +a what about producer Surplus producer +Surplus in the competitive + + align:start position:0% +Surplus in the competitive + + + align:start position:0% +Surplus in the competitive +case was just D plus e well now what is + + align:start position:0% +case was just D plus e well now what is + + + align:start position:0% +case was just D plus e well now what is +it well they lose + + align:start position:0% +it well they lose + + + align:start position:0% +it well they lose +e but they gain + + align:start position:0% + + + + align:start position:0% + +B so what's happened is two things we + + align:start position:0% +B so what's happened is two things we + + + align:start position:0% +B so what's happened is two things we +have + + align:start position:0% +have + + + align:start position:0% +have +transferred area B from consumers to + + align:start position:0% +transferred area B from consumers to + + + align:start position:0% +transferred area B from consumers to +producers remember that's sort of we + + align:start position:0% +producers remember that's sort of we + + + align:start position:0% +producers remember that's sort of we +don't care from that in the total social + + align:start position:0% +don't care from that in the total social + + + align:start position:0% +don't care from that in the total social +welfare framework we just care about the + + align:start position:0% +welfare framework we just care about the + + + align:start position:0% +welfare framework we just care about the +sum producer consumer surplus we don't + + align:start position:0% +sum producer consumer surplus we don't + + + align:start position:0% +sum producer consumer surplus we don't +care who has it so that transfer is not + + align:start position:0% +care who has it so that transfer is not + + + align:start position:0% +care who has it so that transfer is not +important not consequential what's + + align:start position:0% +important not consequential what's + + + align:start position:0% +important not consequential what's +consequential is we've created a dead + + align:start position:0% +consequential is we've created a dead + + + align:start position:0% +consequential is we've created a dead +weight + + align:start position:0% +weight + + + align:start position:0% +weight +loss of of + + align:start position:0% +loss of of + + + align:start position:0% +loss of of +c+e we've created a dead weight loss of + + align:start position:0% +c+e we've created a dead weight loss of + + + align:start position:0% +c+e we've created a dead weight loss of +c+e there's an inefficiency why because + + align:start position:0% +c+e there's an inefficiency why because + + + align:start position:0% +c+e there's an inefficiency why because +there are trades that would make Society + + align:start position:0% +there are trades that would make Society + + + align:start position:0% +there are trades that would make Society +better off that are not happening + + align:start position:0% +better off that are not happening + + + align:start position:0% +better off that are not happening +remember if we went if we sold that + + align:start position:0% +remember if we went if we sold that + + + align:start position:0% +remember if we went if we sold that +seventh + + align:start position:0% + + + + align:start position:0% + +unit could the benefit of that unit to + + align:start position:0% +unit could the benefit of that unit to + + + align:start position:0% +unit could the benefit of that unit to +Consumers exceeds the cost of producing + + align:start position:0% +Consumers exceeds the cost of producing + + + align:start position:0% +Consumers exceeds the cost of producing +it therefore society's better off if + + align:start position:0% +it therefore society's better off if + + + align:start position:0% +it therefore society's better off if +it's sold but it's not being sold + + align:start position:0% +it's sold but it's not being sold + + + align:start position:0% +it's sold but it's not being sold +because this poisoning effect so + + align:start position:0% +because this poisoning effect so + + + align:start position:0% +because this poisoning effect so +Monopoly has created a dead weight loss + + align:start position:0% +Monopoly has created a dead weight loss + + + align:start position:0% +Monopoly has created a dead weight loss +and the first example the dead weight + + align:start position:0% +and the first example the dead weight + + + align:start position:0% +and the first example the dead weight +loss and + + align:start position:0% +loss and + + + align:start position:0% +loss and +Monopoly is the first example of what we + + align:start position:0% +Monopoly is the first example of what we + + + align:start position:0% +Monopoly is the first example of what we +call in this class a + + align:start position:0% + + + + align:start position:0% + +market + + align:start position:0% +market + + + align:start position:0% +market +failure when I did welfare the last + + align:start position:0% +failure when I did welfare the last + + + align:start position:0% +failure when I did welfare the last +couple lectures the only thing that + + align:start position:0% +couple lectures the only thing that + + + align:start position:0% +couple lectures the only thing that +caused de loss was the government + + align:start position:0% +caused de loss was the government + + + align:start position:0% +caused de loss was the government +screwing things up as long as you left + + align:start position:0% +screwing things up as long as you left + + + align:start position:0% +screwing things up as long as you left +the market rip you got the perfectly + + align:start position:0% +the market rip you got the perfectly + + + align:start position:0% +the market rip you got the perfectly +efficient outcome well here we're + + align:start position:0% +efficient outcome well here we're + + + align:start position:0% +efficient outcome well here we're +letting the market rip and not getting + + align:start position:0% +letting the market rip and not getting + + + align:start position:0% +letting the market rip and not getting +the perfectly efficient outcome now I'll + + align:start position:0% +the perfectly efficient outcome now I'll + + + align:start position:0% +the perfectly efficient outcome now I'll +stop right there this does not imply + + align:start position:0% +stop right there this does not imply + + + align:start position:0% +stop right there this does not imply +government can make things better we'll + + align:start position:0% +government can make things better we'll + + + align:start position:0% +government can make things better we'll +talk about that next time all I'm saying + + align:start position:0% +talk about that next time all I'm saying + + + align:start position:0% +talk about that next time all I'm saying +here is a simpler statement which is + + align:start position:0% +here is a simpler statement which is + + + align:start position:0% +here is a simpler statement which is +unlike the perfectly competitive case if + + align:start position:0% +unlike the perfectly competitive case if + + + align:start position:0% +unlike the perfectly competitive case if +you let the market rip you get an + + align:start position:0% +you let the market rip you get an + + + align:start position:0% +you let the market rip you get an +inefficient + + align:start position:0% +inefficient + + + align:start position:0% +inefficient +outcome that's a fundamental change + + align:start position:0% +outcome that's a fundamental change + + + align:start position:0% +outcome that's a fundamental change +that's a fundamental challenge to + + align:start position:0% +that's a fundamental challenge to + + + align:start position:0% +that's a fundamental challenge to +everything we've learned so far it + + align:start position:0% +everything we've learned so far it + + + align:start position:0% +everything we've learned so far it +doesn't come from any magic or any + + align:start position:0% +doesn't come from any magic or any + + + align:start position:0% +doesn't come from any magic or any +government intervention it's just the + + align:start position:0% +government intervention it's just the + + + align:start position:0% +government intervention it's just the +way monopolis make + + align:start position:0% +way monopolis make + + + align:start position:0% +way monopolis make +decisions okay so because monopolis + + align:start position:0% +decisions okay so because monopolis + + + align:start position:0% +decisions okay so because monopolis +don't want to lower the price because + + align:start position:0% +don't want to lower the price because + + + align:start position:0% +don't want to lower the price because +that's not profit maximizing we end up + + align:start position:0% +that's not profit maximizing we end up + + + align:start position:0% +that's not profit maximizing we end up +not selling units that and that would + + align:start position:0% +not selling units that and that would + + + align:start position:0% +not selling units that and that would +make Society better off so the private + + align:start position:0% +make Society better off so the private + + + align:start position:0% +make Society better off so the private +incentives put another way the positive + + align:start position:0% +incentives put another way the positive + + + align:start position:0% +incentives put another way the positive +and normative outcomes don't don't align + + align:start position:0% +and normative outcomes don't don't align + + + align:start position:0% +and normative outcomes don't don't align +with the competitive market the positive + + align:start position:0% +with the competitive market the positive + + + align:start position:0% +with the competitive market the positive +outcome was no profits that was also the + + align:start position:0% +outcome was no profits that was also the + + + align:start position:0% +outcome was no profits that was also the +welfare maximizing outcome in a monopoly + + align:start position:0% +welfare maximizing outcome in a monopoly + + + align:start position:0% +welfare maximizing outcome in a monopoly +case the private + + align:start position:0% +case the private + + + align:start position:0% +case the private +outcome is different than the social + + align:start position:0% +outcome is different than the social + + + align:start position:0% +outcome is different than the social +welfare maximizing outcome and that lead + + align:start position:0% +welfare maximizing outcome and that lead + + + align:start position:0% +welfare maximizing outcome and that lead +leads to a market failure questions + + align:start position:0% +leads to a market failure questions + + + align:start position:0% +leads to a market failure questions +about + + align:start position:0% +about + + + align:start position:0% +about +that okay + + align:start position:0% +that okay + + + align:start position:0% +that okay +now this raises the natural question + + align:start position:0% +now this raises the natural question + + + align:start position:0% +now this raises the natural question +which was raised here and which has been + + align:start position:0% +which was raised here and which has been + + + align:start position:0% +which was raised here and which has been +on your mind the whole time which is why + + align:start position:0% +on your mind the whole time which is why + + + align:start position:0% +on your mind the whole time which is why +do monopolis have to charge just one + + align:start position:0% +do monopolis have to charge just one + + + align:start position:0% +do monopolis have to charge just one +price what loss is that no firm charge + + align:start position:0% +price what loss is that no firm charge + + + align:start position:0% +price what loss is that no firm charge +is just one price firms charge different + + align:start position:0% +is just one price firms charge different + + + align:start position:0% +is just one price firms charge different +prices for different sorts of things you + + align:start position:0% +prices for different sorts of things you + + + align:start position:0% +prices for different sorts of things you +know for different and we'll come to + + align:start position:0% +know for different and we'll come to + + + align:start position:0% +know for different and we'll come to +some examples so what if we move to the + + align:start position:0% +some examples so what if we move to the + + + align:start position:0% +some examples so what if we move to the +more realistic case where monopolist can + + align:start position:0% +more realistic case where monopolist can + + + align:start position:0% +more realistic case where monopolist can +price + + align:start position:0% +price + + + align:start position:0% +price +discriminate what if monopolis could + + align:start position:0% +discriminate what if monopolis could + + + align:start position:0% +discriminate what if monopolis could +charge different prices for different + + align:start position:0% +charge different prices for different + + + align:start position:0% +charge different prices for different +quantities well in fact what would + + align:start position:0% +quantities well in fact what would + + + align:start position:0% +quantities well in fact what would +happen let's go to the extreme of + + align:start position:0% +happen let's go to the extreme of + + + align:start position:0% +happen let's go to the extreme of +perfect price + + align:start position:0% +perfect price + + + align:start position:0% +perfect price +discrimination Perfect Right + + align:start position:0% +discrimination Perfect Right + + + align:start position:0% +discrimination Perfect Right +discrimination is a magag monopolist + + align:start position:0% +discrimination is a magag monopolist + + + align:start position:0% +discrimination is a magag monopolist +could go to Every + + align:start position:0% +could go to Every + + + align:start position:0% +could go to Every +individual figure out what their + + align:start position:0% +individual figure out what their + + + align:start position:0% +individual figure out what their +willingness to pay was and charge them + + align:start position:0% +willingness to pay was and charge them + + + align:start position:0% +willingness to pay was and charge them +that + + align:start position:0% +that + + + align:start position:0% +that +amount that'd be perfectly price + + align:start position:0% +amount that'd be perfectly price + + + align:start position:0% +amount that'd be perfectly price +discriminating monopolis they would + + align:start position:0% +discriminating monopolis they would + + + align:start position:0% +discriminating monopolis they would +charge every person their own individual + + align:start position:0% +charge every person their own individual + + + align:start position:0% +charge every person their own individual +price and that price will correspond to + + align:start position:0% +price and that price will correspond to + + + align:start position:0% +price and that price will correspond to +their willingness to + + align:start position:0% +their willingness to + + + align:start position:0% +their willingness to +pay what would that lead to that would + + align:start position:0% +pay what would that lead to that would + + + align:start position:0% +pay what would that lead to that would +lead to figure + + align:start position:0% +lead to figure + + + align:start position:0% +lead to figure +116 the first person person + + align:start position:0% +116 the first person person + + + align:start position:0% +116 the first person person +one they are willing to pay that entire + + align:start position:0% +one they are willing to pay that entire + + + align:start position:0% +one they are willing to pay that entire +um uh trapezoid that'll be to the left + + align:start position:0% +um uh trapezoid that'll be to the left + + + align:start position:0% +um uh trapezoid that'll be to the left +of unit one they only pay a lot so you + + align:start position:0% +of unit one they only pay a lot so you + + + align:start position:0% +of unit one they only pay a lot so you +charge them a lot all the way down to + + align:start position:0% +charge them a lot all the way down to + + + align:start position:0% +charge them a lot all the way down to +the eighth person you charge them what + + align:start position:0% +the eighth person you charge them what + + + align:start position:0% +the eighth person you charge them what +they're willing to pay which is 16 + + align:start position:0% +they're willing to pay which is 16 + + + align:start position:0% +they're willing to pay which is 16 +charge the eighth person 16 the seventh + + align:start position:0% +charge the eighth person 16 the seventh + + + align:start position:0% +charge the eighth person 16 the seventh +person 17 the sixth person 18 and so on + + align:start position:0% +person 17 the sixth person 18 and so on + + + align:start position:0% +person 17 the sixth person 18 and so on +why would you want to do + + align:start position:0% +why would you want to do + + + align:start position:0% +why would you want to do +that well now what has happened to + + align:start position:0% +that well now what has happened to + + + align:start position:0% +that well now what has happened to +consumer surplus someone raise their + + align:start position:0% +consumer surplus someone raise their + + + align:start position:0% +consumer surplus someone raise their +hand and tell me yeah zero why is + + align:start position:0% +hand and tell me yeah zero why is + + + align:start position:0% +hand and tell me yeah zero why is +consumer surplus + + align:start position:0% + + + + align:start position:0% + +zero exactly consumer surplus is the + + align:start position:0% +zero exactly consumer surplus is the + + + align:start position:0% +zero exactly consumer surplus is the +benefit you get from valuing something + + align:start position:0% +benefit you get from valuing something + + + align:start position:0% +benefit you get from valuing something +above its price that's gone they're + + align:start position:0% +above its price that's gone they're + + + align:start position:0% +above its price that's gone they're +charging you what you're willing to pay + + align:start position:0% +charging you what you're willing to pay + + + align:start position:0% +charging you what you're willing to pay +so by definition there's no consumer + + align:start position:0% +so by definition there's no consumer + + + align:start position:0% +so by definition there's no consumer +surplus so all the rest is producer + + align:start position:0% +surplus so all the rest is producer + + + align:start position:0% +surplus so all the rest is producer +Surplus so the firm has converted the + + align:start position:0% +Surplus so the firm has converted the + + + align:start position:0% +Surplus so the firm has converted the +entire Surplus to producer Surplus by + + align:start position:0% +entire Surplus to producer Surplus by + + + align:start position:0% +entire Surplus to producer Surplus by +Perfect price + + align:start position:0% +Perfect price + + + align:start position:0% +Perfect price +discrimination what else is notable in + + align:start position:0% +discrimination what else is notable in + + + align:start position:0% +discrimination what else is notable in +this case with per price discrimination + + align:start position:0% +this case with per price discrimination + + + align:start position:0% +this case with per price discrimination +firms will sell eight units so what else + + align:start position:0% +firms will sell eight units so what else + + + align:start position:0% +firms will sell eight units so what else +is notable no dead weight + + align:start position:0% +is notable no dead weight + + + align:start position:0% +is notable no dead weight +loss a perfectly priced discriminating + + align:start position:0% +loss a perfectly priced discriminating + + + align:start position:0% +loss a perfectly priced discriminating +firm creates no dead weight loss why + + align:start position:0% +firm creates no dead weight loss why + + + align:start position:0% +firm creates no dead weight loss why +because there's no poisoning effect the + + align:start position:0% +because there's no poisoning effect the + + + align:start position:0% +because there's no poisoning effect the +poisoning effect comes from the fact + + align:start position:0% +poisoning effect comes from the fact + + + align:start position:0% +poisoning effect comes from the fact +that if I want to sell more units I got + + align:start position:0% +that if I want to sell more units I got + + + align:start position:0% +that if I want to sell more units I got +to lower my price well here I don't have + + align:start position:0% +to lower my price well here I don't have + + + align:start position:0% +to lower my price well here I don't have +to lower my price to sell more units + + align:start position:0% +to lower my price to sell more units + + + align:start position:0% +to lower my price to sell more units +given that I might as well sell as many + + align:start position:0% +given that I might as well sell as many + + + align:start position:0% +given that I might as well sell as many +units as people are willing to pay for + + align:start position:0% +units as people are willing to pay for + + + align:start position:0% +units as people are willing to pay for +that are above my cost so I might as + + align:start position:0% +that are above my cost so I might as + + + align:start position:0% +that are above my cost so I might as +well do the welfare maximizing thing + + align:start position:0% +well do the welfare maximizing thing + + + align:start position:0% +well do the welfare maximizing thing +which is sell 8 + + align:start position:0% +which is sell 8 + + + align:start position:0% +which is sell 8 +units this is the first inclination that + + align:start position:0% +units this is the first inclination that + + + align:start position:0% +units this is the first inclination that +we have to car care about fairness in + + align:start position:0% +we have to car care about fairness in + + + align:start position:0% +we have to car care about fairness in +economics because what this says what + + align:start position:0% +economics because what this says what + + + align:start position:0% +economics because what this says what +the existing course would teach you so + + align:start position:0% +the existing course would teach you so + + + align:start position:0% +the existing course would teach you so +far is I'm completely + + align:start position:0% +far is I'm completely + + + align:start position:0% +far is I'm completely +indifferent between the perfectly + + align:start position:0% +indifferent between the perfectly + + + align:start position:0% +indifferent between the perfectly +competitive case as illustrated by EC + + align:start position:0% +competitive case as illustrated by EC + + + align:start position:0% +competitive case as illustrated by EC +above where consumers get a plus b plus + + align:start position:0% +above where consumers get a plus b plus + + + align:start position:0% +above where consumers get a plus b plus +C I'm indifferent between that case and + + align:start position:0% +C I'm indifferent between that case and + + + align:start position:0% +C I'm indifferent between that case and +the perfect price discrimination case + + align:start position:0% +the perfect price discrimination case + + + align:start position:0% +the perfect price discrimination case +that is I'm indifferent between whether + + align:start position:0% +that is I'm indifferent between whether + + + align:start position:0% +that is I'm indifferent between whether +consumer's + + align:start position:0% +consumer's + + + align:start position:0% +consumer's +gift okay I'm completely indifferent all + + align:start position:0% +gift okay I'm completely indifferent all + + + align:start position:0% +gift okay I'm completely indifferent all +I care about is the total right it's the + + align:start position:0% +I care about is the total right it's the + + + align:start position:0% +I care about is the total right it's the +sum that can't make sense right it can't + + align:start position:0% +sum that can't make sense right it can't + + + align:start position:0% +sum that can't make sense right it can't +make sense that I'm completely different + + align:start position:0% +make sense that I'm completely different + + + align:start position:0% +make sense that I'm completely different +in a world where producers have + + align:start position:0% +in a world where producers have + + + align:start position:0% +in a world where producers have +everything and where consumers have some + + align:start position:0% +everything and where consumers have some + + + align:start position:0% +everything and where consumers have some +producers have some there's no way that + + align:start position:0% +producers have some there's no way that + + + align:start position:0% +producers have some there's no way that +anyone would be truly indifferent in + + align:start position:0% +anyone would be truly indifferent in + + + align:start position:0% +anyone would be truly indifferent in +those worlds and that's the first hint + + align:start position:0% +those worlds and that's the first hint + + + align:start position:0% +those worlds and that's the first hint +that in economics we have to care about + + align:start position:0% +that in economics we have to care about + + + align:start position:0% +that in economics we have to care about +fairness we have to not just care about + + align:start position:0% +fairness we have to not just care about + + + align:start position:0% +fairness we have to not just care about +the total sum of social surplus but who + + align:start position:0% +the total sum of social surplus but who + + + align:start position:0% +the total sum of social surplus but who +gets + + align:start position:0% +gets + + + align:start position:0% +gets +what okay and we're going to come back + + align:start position:0% +what okay and we're going to come back + + + align:start position:0% +what okay and we're going to come back +to that later for now we'll stick with + + align:start position:0% +to that later for now we'll stick with + + + align:start position:0% +to that later for now we'll stick with +our definition we're just care about the + + align:start position:0% +our definition we're just care about the + + + align:start position:0% +our definition we're just care about the +total but this is sort of the hint of + + align:start position:0% +total but this is sort of the hint of + + + align:start position:0% +total but this is sort of the hint of +why we need to come back to + + align:start position:0% +why we need to come back to + + + align:start position:0% +why we need to come back to +that okay so that is what would happen + + align:start position:0% +that okay so that is what would happen + + + align:start position:0% +that okay so that is what would happen +with perfect price discrimination now in + + align:start position:0% +with perfect price discrimination now in + + + align:start position:0% +with perfect price discrimination now in +fact okay um firms can't perfectly price + + align:start position:0% +fact okay um firms can't perfectly price + + + align:start position:0% +fact okay um firms can't perfectly price +discriminate in fact firms can't go and + + align:start position:0% +discriminate in fact firms can't go and + + + align:start position:0% +discriminate in fact firms can't go and +get your willingness to pay so in + + align:start position:0% +get your willingness to pay so in + + + align:start position:0% +get your willingness to pay so in +reality what do firms do well they price + + align:start position:0% +reality what do firms do well they price + + + align:start position:0% +reality what do firms do well they price +discriminate by trying to guess who is + + align:start position:0% +discriminate by trying to guess who is + + + align:start position:0% +discriminate by trying to guess who is +more price + + align:start position:0% +more price + + + align:start position:0% +more price +sensitive firms engage in price + + align:start position:0% +sensitive firms engage in price + + + align:start position:0% +sensitive firms engage in price +discrimination and the way they do it is + + align:start position:0% +discrimination and the way they do it is + + + align:start position:0% +discrimination and the way they do it is +they look for correlates of + + align:start position:0% +they look for correlates of + + + align:start position:0% +they look for correlates of +Epsilon you you basically if you're a + + align:start position:0% +Epsilon you you basically if you're a + + + align:start position:0% +Epsilon you you basically if you're a +monopolist you want to charge a higher + + align:start position:0% +monopolist you want to charge a higher + + + align:start position:0% +monopolist you want to charge a higher +price to a low Epsilon guy and a low + + align:start position:0% +price to a low Epsilon guy and a low + + + align:start position:0% +price to a low Epsilon guy and a low +remember guys gender neutral term and a + + align:start position:0% +remember guys gender neutral term and a + + + align:start position:0% +remember guys gender neutral term and a +lower price to a high Epsilon guy so + + align:start position:0% +lower price to a high Epsilon guy so + + + align:start position:0% +lower price to a high Epsilon guy so +basically if I knew everyone's Epsilon + + align:start position:0% +basically if I knew everyone's Epsilon + + + align:start position:0% +basically if I knew everyone's Epsilon +I'd be done but I don't so what I do is + + align:start position:0% +I'd be done but I don't so what I do is + + + align:start position:0% +I'd be done but I don't so what I do is +I look for signals that are correlated + + align:start position:0% +I look for signals that are correlated + + + align:start position:0% +I look for signals that are correlated +with your + + align:start position:0% +with your + + + align:start position:0% +with your +Epsilon so for + + align:start position:0% +Epsilon so for + + + align:start position:0% +Epsilon so for +example airlines charge more if you buy + + align:start position:0% +example airlines charge more if you buy + + + align:start position:0% +example airlines charge more if you buy +at the last minute + + align:start position:0% +at the last minute + + + align:start position:0% +at the last minute +that if you buy four months in + + align:start position:0% +that if you buy four months in + + + align:start position:0% +that if you buy four months in +advance why it's the same seat same + + align:start position:0% +advance why it's the same seat same + + + align:start position:0% +advance why it's the same seat same +produ same marginal cost to flying on + + align:start position:0% +produ same marginal cost to flying on + + + align:start position:0% +produ same marginal cost to flying on +the plane + + align:start position:0% +the plane + + + align:start position:0% +the plane +yeah yeah if you buy the last you + + align:start position:0% +yeah yeah if you buy the last you + + + align:start position:0% +yeah yeah if you buy the last you +clearly got to go okay you're a business + + align:start position:0% +clearly got to go okay you're a business + + + align:start position:0% +clearly got to go okay you're a business +person's got a last minute meeting + + align:start position:0% +person's got a last minute meeting + + + align:start position:0% +person's got a last minute meeting +you've gotta you've got to love one + + align:start position:0% +you've gotta you've got to love one + + + align:start position:0% +you've gotta you've got to love one +who's sick who's got you got to go see + + align:start position:0% +who's sick who's got you got to go see + + + align:start position:0% +who's sick who's got you got to go see +Etc if you buy four months in advance + + align:start position:0% +Etc if you buy four months in advance + + + align:start position:0% +Etc if you buy four months in advance +you're clearly shopping you have lots of + + align:start position:0% +you're clearly shopping you have lots of + + + align:start position:0% +you're clearly shopping you have lots of +options but if you're buying the last + + align:start position:0% +options but if you're buying the last + + + align:start position:0% +options but if you're buying the last +minute you don't have a lot of options + + align:start position:0% +minute you don't have a lot of options + + + align:start position:0% +minute you don't have a lot of options +now I can't charge you infinity because + + align:start position:0% +now I can't charge you infinity because + + + align:start position:0% +now I can't charge you infinity because +as other airlines you could fly but + + align:start position:0% +as other airlines you could fly but + + + align:start position:0% +as other airlines you could fly but +clearly you are less price sensitive if + + align:start position:0% +clearly you are less price sensitive if + + + align:start position:0% +clearly you are less price sensitive if +you're buying at the last minute than if + + align:start position:0% +you're buying at the last minute than if + + + align:start position:0% +you're buying at the last minute than if +you're buying four months in + + align:start position:0% +you're buying four months in + + + align:start position:0% +you're buying four months in +advance that's one example okay why do + + align:start position:0% +advance that's one example okay why do + + + align:start position:0% +advance that's one example okay why do +movie theaters charge less for Maes than + + align:start position:0% +movie theaters charge less for Maes than + + + align:start position:0% +movie theaters charge less for Maes than +movies at night why do movie theaters + + align:start position:0% +movies at night why do movie theaters + + + align:start position:0% +movies at night why do movie theaters +charge less when you go during the day + + align:start position:0% +charge less when you go during the day + + + align:start position:0% +charge less when you go during the day +it's the same marginal cost again same + + align:start position:0% +it's the same marginal cost again same + + + align:start position:0% +it's the same marginal cost again same +popcorn cost same projector costs why do + + align:start position:0% +popcorn cost same projector costs why do + + + align:start position:0% +popcorn cost same projector costs why do +movie theaters charge less when you go + + align:start position:0% +movie theaters charge less when you go + + + align:start position:0% +movie theaters charge less when you go +during the day + + align:start position:0% + + + + align:start position:0% + +yeah well lower Demand by itself is not + + align:start position:0% +yeah well lower Demand by itself is not + + + align:start position:0% +yeah well lower Demand by itself is not +necessarily the answer it's really about + + align:start position:0% +necessarily the answer it's really about + + + align:start position:0% +necessarily the answer it's really about +elasticity of demand why are people less + + align:start position:0% +elasticity of demand why are people less + + + align:start position:0% +elasticity of demand why are people less +price sensitive during the why are + + align:start position:0% +price sensitive during the why are + + + align:start position:0% +price sensitive during the why are +people more price sensitive during the + + align:start position:0% +people more price sensitive during the + + + align:start position:0% +people more price sensitive during the +day than at + + align:start position:0% +day than at + + + align:start position:0% +day than at +night think about who goes to the movies + + align:start position:0% +night think about who goes to the movies + + + align:start position:0% +night think about who goes to the movies +during the + + align:start position:0% + + + + align:start position:0% + +day yeah mean people are like retirees + + align:start position:0% +day yeah mean people are like retirees + + + align:start position:0% +day yeah mean people are like retirees +and things which have plenty of time in + + align:start position:0% +and things which have plenty of time in + + + align:start position:0% +and things which have plenty of time in +their hands if you go to the movie at + + align:start position:0% +their hands if you go to the movie at + + + align:start position:0% +their hands if you go to the movie at +night it's like you're done with work + + align:start position:0% +night it's like you're done with work + + + align:start position:0% +night it's like you're done with work +you got to go at night you can't you + + align:start position:0% +you got to go at night you can't you + + + align:start position:0% +you got to go at night you can't you +know maybe you decide between the 7 + + align:start position:0% +know maybe you decide between the 7 + + + align:start position:0% +know maybe you decide between the 7 +o'clock showing the 11:00 showing but + + align:start position:0% +o'clock showing the 11:00 showing but + + + align:start position:0% +o'clock showing the 11:00 showing but +the bottom line is there's one time you + + align:start position:0% +the bottom line is there's one time you + + + align:start position:0% +the bottom line is there's one time you +can go if you're going during the day + + align:start position:0% +can go if you're going during the day + + + align:start position:0% +can go if you're going during the day +you've shown you have lots of time to go + + align:start position:0% +you've shown you have lots of time to go + + + align:start position:0% +you've shown you have lots of time to go +see movies you can go at night you can + + align:start position:0% +see movies you can go at night you can + + + align:start position:0% +see movies you can go at night you can +go during the day so anybody who goes to + + align:start position:0% +go during the day so anybody who goes to + + + align:start position:0% +go during the day so anybody who goes to +movie during the day unless they work a + + align:start position:0% +movie during the day unless they work a + + + align:start position:0% +movie during the day unless they work a +weird shift okay has basically shown + + align:start position:0% +weird shift okay has basically shown + + + align:start position:0% +weird shift okay has basically shown +that they have more flexibility on when + + align:start position:0% +that they have more flexibility on when + + + align:start position:0% +that they have more flexibility on when +they go to the + + align:start position:0% +they go to the + + + align:start position:0% +they go to the +movie as a result you charge them a + + align:start position:0% +movie as a result you charge them a + + + align:start position:0% +movie as a result you charge them a +lower + + align:start position:0% +lower + + + align:start position:0% +lower +price this is everywhere you look all of + + align:start position:0% +price this is everywhere you look all of + + + align:start position:0% +price this is everywhere you look all of +a sudden I've opened up to you a world + + align:start position:0% +a sudden I've opened up to you a world + + + align:start position:0% +a sudden I've opened up to you a world +of understanding why price are + + align:start position:0% +of understanding why price are + + + align:start position:0% +of understanding why price are +differentiated okay remember we + + align:start position:0% +differentiated okay remember we + + + align:start position:0% +differentiated okay remember we +discussed this a long time ago we talked + + align:start position:0% +discussed this a long time ago we talked + + + align:start position:0% +discussed this a long time ago we talked +about why the incremental large + + align:start position:0% +about why the incremental large + + + align:start position:0% +about why the incremental large +drink at McDonald's the incremental cost + + align:start position:0% +drink at McDonald's the incremental cost + + + align:start position:0% +drink at McDonald's the incremental cost +of a large drink is Tri is very small + + align:start position:0% +of a large drink is Tri is very small + + + align:start position:0% +of a large drink is Tri is very small +compared to the cost of a small drink + + align:start position:0% +compared to the cost of a small drink + + + align:start position:0% +compared to the cost of a small drink +because there's different elas demand + + align:start position:0% +because there's different elas demand + + + align:start position:0% +because there's different elas demand +for the small drink and and the + + align:start position:0% +for the small drink and and the + + + align:start position:0% +for the small drink and and the +incremental to the large drink so + + align:start position:0% +incremental to the large drink so + + + align:start position:0% +incremental to the large drink so +everywhere you look when you go out in + + align:start position:0% +everywhere you look when you go out in + + + align:start position:0% +everywhere you look when you go out in +the real world now look at prices you'll + + align:start position:0% +the real world now look at prices you'll + + + align:start position:0% +the real world now look at prices you'll +see this firms pricing to try to Target + + align:start position:0% +see this firms pricing to try to Target + + + align:start position:0% +see this firms pricing to try to Target +the lower prices to the most elastic + + align:start position:0% +the lower prices to the most elastic + + + align:start position:0% +the lower prices to the most elastic +consumers + + align:start position:0% +consumers + + + align:start position:0% +consumers +okay now perhaps the best example of + + align:start position:0% +okay now perhaps the best example of + + + align:start position:0% +okay now perhaps the best example of +this was a example a few years ago with + + align:start position:0% +this was a example a few years ago with + + + align:start position:0% +this was a example a few years ago with +Tesla Tesla sells electric cars you know + + align:start position:0% +Tesla Tesla sells electric cars you know + + + align:start position:0% +Tesla Tesla sells electric cars you know +and the original model S could go for + + align:start position:0% +and the original model S could go for + + + align:start position:0% +and the original model S could go for +250 miles on a battery charge what they + + align:start position:0% +250 miles on a battery charge what they + + + align:start position:0% +250 miles on a battery charge what they +said is we are going to offer a cheaper + + align:start position:0% +said is we are going to offer a cheaper + + + align:start position:0% +said is we are going to offer a cheaper +Model S that can only go about half as + + align:start position:0% +Model S that can only go about half as + + + align:start position:0% +Model S that can only go about half as +far about 125 150 miles per per battery + + align:start position:0% +far about 125 150 miles per per battery + + + align:start position:0% +far about 125 150 miles per per battery +charge so you can buy the more expensive + + align:start position:0% +charge so you can buy the more expensive + + + align:start position:0% +charge so you can buy the more expensive +one because it's got this fancier + + align:start position:0% +one because it's got this fancier + + + align:start position:0% +one because it's got this fancier +battery 250 miles you can go it cost + + align:start position:0% +battery 250 miles you can go it cost + + + align:start position:0% +battery 250 miles you can go it cost +more money or the less expensive one + + align:start position:0% +more money or the less expensive one + + + align:start position:0% +more money or the less expensive one +with a less expens less fancy battery it + + align:start position:0% +with a less expens less fancy battery it + + + align:start position:0% +with a less expens less fancy battery it +only go 150 + + align:start position:0% +only go 150 + + + align:start position:0% +only go 150 +mil well um in September 2017 there was + + align:start position:0% +mil well um in September 2017 there was + + + align:start position:0% +mil well um in September 2017 there was +a huge hurricane in Florida and people + + align:start position:0% +a huge hurricane in Florida and people + + + align:start position:0% +a huge hurricane in Florida and people +had to evacuate and Tesla understood + + align:start position:0% +had to evacuate and Tesla understood + + + align:start position:0% +had to evacuate and Tesla understood +that the limits on how far you could + + align:start position:0% +that the limits on how far you could + + + align:start position:0% +that the limits on how far you could +drive Florida's a big state could get in + + align:start position:0% +drive Florida's a big state could get in + + + align:start position:0% +drive Florida's a big state could get in +the way of people + + align:start position:0% +the way of people + + + align:start position:0% +the way of people +evacuating so Tesla said you know what + + align:start position:0% +evacuating so Tesla said you know what + + + align:start position:0% +evacuating so Tesla said you know what +all cars can now go 250 miles on their + + align:start position:0% +all cars can now go 250 miles on their + + + align:start position:0% +all cars can now go 250 miles on their +battery people like what the what do you + + align:start position:0% +battery people like what the what do you + + + align:start position:0% +battery people like what the what do you +mean we can go 250 miles in the battery + + align:start position:0% +mean we can go 250 miles in the battery + + + align:start position:0% +mean we can go 250 miles in the battery +well turn out it's the same battery they + + align:start position:0% +well turn out it's the same battery they + + + align:start position:0% +well turn out it's the same battery they +just had a piece of code that limited + + align:start position:0% +just had a piece of code that limited + + + align:start position:0% +just had a piece of code that limited +how far you could go in the cheaper car + + align:start position:0% +how far you could go in the cheaper car + + + align:start position:0% +how far you could go in the cheaper car +why would they do that why would they + + align:start position:0% +why would they do that why would they + + + align:start position:0% +why would they do that why would they +literally have the same battery and + + align:start position:0% +literally have the same battery and + + + align:start position:0% +literally have the same battery and +literally add money to add code to limit + + align:start position:0% +literally add money to add code to limit + + + align:start position:0% +literally add money to add code to limit +how far you could go why' they do + + align:start position:0% + + + + align:start position:0% + +that yeah + + align:start position:0% + + + + align:start position:0% + +exactly there's two types of people + + align:start position:0% +exactly there's two types of people + + + align:start position:0% +exactly there's two types of people +people who have a lot of money and are + + align:start position:0% +people who have a lot of money and are + + + align:start position:0% +people who have a lot of money and are +willing to pay for a better car people + + align:start position:0% +willing to pay for a better car people + + + align:start position:0% +willing to pay for a better car people +don't a lot of money not willing to pay + + align:start position:0% +don't a lot of money not willing to pay + + + align:start position:0% +don't a lot of money not willing to pay +for a better car if they just simply + + align:start position:0% +for a better car if they just simply + + + align:start position:0% +for a better car if they just simply +said we're going to sell Modelo 250 + + align:start position:0% +said we're going to sell Modelo 250 + + + align:start position:0% +said we're going to sell Modelo 250 +miles a bunch of lower income people + + align:start position:0% +miles a bunch of lower income people + + + align:start position:0% +miles a bunch of lower income people +wouldn't have bought it if they said + + align:start position:0% +wouldn't have bought it if they said + + + align:start position:0% +wouldn't have bought it if they said +we're going to let everyone go 250 miles + + align:start position:0% +we're going to let everyone go 250 miles + + + align:start position:0% +we're going to let everyone go 250 miles +on a cheaper price then they wouldn't + + align:start position:0% +on a cheaper price then they wouldn't + + + align:start position:0% +on a cheaper price then they wouldn't +have made as much money so they said a + + align:start position:0% +have made as much money so they said a + + + align:start position:0% +have made as much money so they said a +high price for a premium product to grab + + align:start position:0% +high price for a premium product to grab + + + align:start position:0% +high price for a premium product to grab +all the low elasticity consumers and a + + align:start position:0% +all the low elasticity consumers and a + + + align:start position:0% +all the low elasticity consumers and a +lower price for a less premium product + + align:start position:0% +lower price for a less premium product + + + align:start position:0% +lower price for a less premium product +to grab the high elasticity consumers + + align:start position:0% +to grab the high elasticity consumers + + + align:start position:0% +to grab the high elasticity consumers +even though the products were the same + + align:start position:0% +even though the products were the same + + + align:start position:0% +even though the products were the same +this actually uh Tesla is not Al loness + + align:start position:0% +this actually uh Tesla is not Al loness + + + align:start position:0% +this actually uh Tesla is not Al loness +when IBM first created the the uh uh + + align:start position:0% +when IBM first created the the uh uh + + + align:start position:0% +when IBM first created the the uh uh +digital + + align:start position:0% +digital + + + align:start position:0% +digital +printer uh it uh said had a home version + + align:start position:0% +printer uh it uh said had a home version + + + align:start position:0% +printer uh it uh said had a home version +which was much less efficient than the + + align:start position:0% +which was much less efficient than the + + + align:start position:0% +which was much less efficient than the +office version and it turned out someone + + align:start position:0% +office version and it turned out someone + + + align:start position:0% +office version and it turned out someone +took them apart and it was the same + + align:start position:0% +took them apart and it was the same + + + align:start position:0% +took them apart and it was the same +printer there's added crap to the motor + + align:start position:0% +printer there's added crap to the motor + + + align:start position:0% +printer there's added crap to the motor +on the home version to make it go + + align:start position:0% +on the home version to make it go + + + align:start position:0% +on the home version to make it go +slower okay because they want to take + + align:start position:0% +slower okay because they want to take + + + align:start position:0% +slower okay because they want to take +that same Advantage they want to be able + + align:start position:0% +that same Advantage they want to be able + + + align:start position:0% +that same Advantage they want to be able +to charge a lot for the office one + + align:start position:0% +to charge a lot for the office one + + + align:start position:0% +to charge a lot for the office one +because people are less price elastic in + + align:start position:0% +because people are less price elastic in + + + align:start position:0% +because people are less price elastic in +the office okay turns out you could take + + align:start position:0% +the office okay turns out you could take + + + align:start position:0% +the office okay turns out you could take +this too far Amazon tried to go further + + align:start position:0% +this too far Amazon tried to go further + + + align:start position:0% +this too far Amazon tried to go further +with this Amazon actually tried to set + + align:start position:0% +with this Amazon actually tried to set + + + align:start position:0% +with this Amazon actually tried to set +prices by IP + + align:start position:0% +prices by IP + + + align:start position:0% +prices by IP +address so Amazon literally an exercise + + align:start position:0% +address so Amazon literally an exercise + + + align:start position:0% +address so Amazon literally an exercise +where literally they would differentiate + + align:start position:0% +where literally they would differentiate + + + align:start position:0% +where literally they would differentiate +the price you'd see online by your IP + + align:start position:0% +the price you'd see online by your IP + + + align:start position:0% +the price you'd see online by your IP +address why would they do + + align:start position:0% + + + + align:start position:0% + +that why would they be once again + + align:start position:0% +that why would they be once again + + + align:start position:0% +that why would they be once again +regardless of your feelings about Jeff + + align:start position:0% +regardless of your feelings about Jeff + + + align:start position:0% +regardless of your feelings about Jeff +Bezos why would they do that why would + + align:start position:0% +Bezos why would they do that why would + + + align:start position:0% +Bezos why would they do that why would +they differentiate the price + + align:start position:0% +they differentiate the price + + + align:start position:0% +they differentiate the price +yeah yeah but how would they know by + + align:start position:0% +yeah yeah but how would they know by + + + align:start position:0% +yeah yeah but how would they know by +your IP + + align:start position:0% +your IP + + + align:start position:0% +your IP +address what's + + align:start position:0% +address what's + + + align:start position:0% +address what's +that P sales is one reason what else + + align:start position:0% +that P sales is one reason what else + + + align:start position:0% +that P sales is one reason what else +yeah your ZIP code that's another + + align:start position:0% +yeah your ZIP code that's another + + + align:start position:0% +yeah your ZIP code that's another +reason what else who's willing to pay a + + align:start position:0% +reason what else who's willing to pay a + + + align:start position:0% +reason what else who's willing to pay a +lot yeah what's that yeah basically if + + align:start position:0% +lot yeah what's that yeah basically if + + + align:start position:0% +lot yeah what's that yeah basically if +you're ordering from Goldman Sachs IP + + align:start position:0% +you're ordering from Goldman Sachs IP + + + align:start position:0% +you're ordering from Goldman Sachs IP +address they're like you're rich we're + + align:start position:0% +address they're like you're rich we're + + + align:start position:0% +address they're like you're rich we're +going to charge you a lot if you're + + align:start position:0% +going to charge you a lot if you're + + + align:start position:0% +going to charge you a lot if you're +ordering from some you know homeless + + align:start position:0% +ordering from some you know homeless + + + align:start position:0% +ordering from some you know homeless +shelter or some place people don't have + + align:start position:0% +shelter or some place people don't have + + + align:start position:0% +shelter or some place people don't have +any money they'll charge you less so + + align:start position:0% +any money they'll charge you less so + + + align:start position:0% +any money they'll charge you less so +basically they said we've got a great IP + + align:start position:0% +basically they said we've got a great IP + + + align:start position:0% +basically they said we've got a great IP +address is a great signal of willingness + + align:start position:0% +address is a great signal of willingness + + + align:start position:0% +address is a great signal of willingness +to pay will suck up all that consumer + + align:start position:0% +to pay will suck up all that consumer + + + align:start position:0% +to pay will suck up all that consumer +surplus by varying the price by + + align:start position:0% +surplus by varying the price by + + + align:start position:0% +surplus by varying the price by +willingness to pay they got busted and + + align:start position:0% +willingness to pay they got busted and + + + align:start position:0% +willingness to pay they got busted and +couldn't do it + + align:start position:0% +couldn't do it + + + align:start position:0% +couldn't do it +anymore uh they were told they couldn't + + align:start position:0% +anymore uh they were told they couldn't + + + align:start position:0% +anymore uh they were told they couldn't +do that now it's not clear why not uh in + + align:start position:0% +do that now it's not clear why not uh in + + + align:start position:0% +do that now it's not clear why not uh in +fact the reason why not you might say + + align:start position:0% +fact the reason why not you might say + + + align:start position:0% +fact the reason why not you might say +well look why shouldn't they do that + + align:start position:0% +well look why shouldn't they do that + + + align:start position:0% +well look why shouldn't they do that +they're increasing efficiency if they + + align:start position:0% +they're increasing efficiency if they + + + align:start position:0% +they're increasing efficiency if they +don't do that we're losing C plus e by + + align:start position:0% +don't do that we're losing C plus e by + + + align:start position:0% +don't do that we're losing C plus e by +doing that we're gaining efficiency + + align:start position:0% +doing that we're gaining efficiency + + + align:start position:0% +doing that we're gaining efficiency +they're selling more units they wouldn't + + align:start position:0% +they're selling more units they wouldn't + + + align:start position:0% +they're selling more units they wouldn't +have sold those low-income consumers + + align:start position:0% +have sold those low-income consumers + + + align:start position:0% +have sold those low-income consumers +Tesla wouldn't have sold those cheaper + + align:start position:0% +Tesla wouldn't have sold those cheaper + + + align:start position:0% +Tesla wouldn't have sold those cheaper +model X's or whatever they were so + + align:start position:0% +model X's or whatever they were so + + + align:start position:0% +model X's or whatever they were so +what's wrong with that and the answer is + + align:start position:0% +what's wrong with that and the answer is + + + align:start position:0% +what's wrong with that and the answer is +in a tral economics world nothing TR + + align:start position:0% +in a tral economics world nothing TR + + + align:start position:0% +in a tral economics world nothing TR +economics world we should have let Tesla + + align:start position:0% +economics world we should have let Tesla + + + align:start position:0% +economics world we should have let Tesla +do that we should have let IBM make the + + align:start position:0% +do that we should have let IBM make the + + + align:start position:0% +do that we should have let IBM make the +crappy home printer we should have let + + align:start position:0% +crappy home printer we should have let + + + align:start position:0% +crappy home printer we should have let +Amazon differentiate by IP address the + + align:start position:0% +Amazon differentiate by IP address the + + + align:start position:0% +Amazon differentiate by IP address the +reason we didn't speaks the fact that + + align:start position:0% +reason we didn't speaks the fact that + + + align:start position:0% +reason we didn't speaks the fact that +people don't think consumer producer + + align:start position:0% +people don't think consumer producer + + + align:start position:0% +people don't think consumer producer +Surplus are really valed equally that we + + align:start position:0% +Surplus are really valed equally that we + + + align:start position:0% +Surplus are really valed equally that we +care about both separately and that's + + align:start position:0% +care about both separately and that's + + + align:start position:0% +care about both separately and that's +what we'll start talking about more in a + + align:start position:0% +what we'll start talking about more in a + + + align:start position:0% +what we'll start talking about more in a +few lectures okay questions about that + + align:start position:0% +few lectures okay questions about that + + + align:start position:0% +few lectures okay questions about that +all right uh we'll come back on + + align:start position:0% +all right uh we'll come back on + + + align:start position:0% +all right uh we'll come back on +Wednesday do a second Monopoly lecture + + align:start position:0% +Wednesday do a second Monopoly lecture + + + align:start position:0% +Wednesday do a second Monopoly lecture +you're responsible for the lectures this + + align:start position:0% +you're responsible for the lectures this + + + align:start position:0% +you're responsible for the lectures this +week on the midterm Monday's lecture + + align:start position:0% +week on the midterm Monday's lecture + + + align:start position:0% +week on the midterm Monday's lecture +will go on a new topic which is not in + + align:start position:0% +will go on a new topic which is not in + + + align:start position:0% +will go on a new topic which is not in +the midterm but it's on the final so you + + align:start position:0% +the midterm but it's on the final so you + + + align:start position:0% +the midterm but it's on the final so you +don't want to miss it plus it involves + + align:start position:0% +don't want to miss it plus it involves + + + align:start position:0% +don't want to miss it plus it involves +allop which is fun \ No newline at end of file diff --git a/CSkcBXUIJh4.txt b/CSkcBXUIJh4.txt new file mode 100644 index 0000000000000000000000000000000000000000..a7ec1bdd7ddaa933916d9a45c7a75cd936cd4e37 --- /dev/null +++ b/CSkcBXUIJh4.txt @@ -0,0 +1,529 @@ +Hey guys. + +Welcome back. + +Today we're going to do a fun +problem that will test your + +knowledge of the law +of total variance. + +And in the process, we'll also +get more practice dealing with + +joint PDFs and computing +conditional expectations and + +conditional variances. + +So in this problem, we are given +a joint PDF for x and y. + +So we're told that x and y can +take on the following values + +in the shape of this + +parallelogram, which I've drawn. + +And moreover, that x and y are +uniformly distributed. + +So the joint PDF is just flat +over this parallelogram. + +And because the parallelogram +has an area of 1, the height + +of the PDF must also be 1 so +that the PDF integrates to 1. + +OK. + +And then we are asked +to compute the + +variance of x plus y. + +So you can think of x plus y as +a new random variable whose + +variance we want to compute. + +And moreover, we're told we +should compute this variance + +by using something called the +law of total variance. + +So from lecture, you should +remember or you should recall + +that the law of total variance +can be written + +in these two ways. + +And the reason why there's two +different forms for this case + +is because the formula +always has you + +conditioning on something. + +Here we condition on x, here +we condition on y. + +And for this problem, the +logical choice you have for + +what to condition +on is x or y. + +So again, we have this option. + +And my claim is that we +should condition on x. + +And the reason has to do with +the geometry of this diagram. + +So notice that if you freeze an +x and then you sort of vary + +x, the width of this +parallelogram stays constant. + +However, if you condition on y +and look at the width this + +way, you see that the width +of the slices you get by + +conditioning vary with y. + +So to make our lives easier, +we're going to condition on x. + +And I'm going to erase this +bottom one, because + +we're not using it. + +So this really can seem quite +intimidating, because we have + +nested variances and +expectations going on, but + +we'll just take it slowly +step by step. + +So first, I want to focus +on this term-- + +the conditional expectation of +x plus y conditioned on x. + +So coming back over to this +picture, if you fix an + +arbitrary x in the interval, +0 to 1, we're restricting + +ourselves to this universe. + +So y can only vary between this +point and this point. + +Now, I've already written down +here that the formula for this + +line is given by y +is equal to x. + +And the formula for this +line is given by y is + +equal to x plus 1. + +So in particular, when we +condition on x, we know that y + +varies between x and x plus 1. + +But we actually know +more than that. + +We know that in the +unconditional universe, x and + +y were uniformly distributed. + +So it follows that in the +conditional universe, y should + +also be uniformly distributed, +because conditioning doesn't + +change the relative frequency +of outcomes. + +So that reasoning means that +we can draw the conditional + +PDF of y conditioned +on x as this. + +We said it varies between +x and x plus 1. + +And we also said that it's +uniform, which means that it + +must have a height of 1. + +So this is py given +x, y given x. + +Now, you might be concerned, +because, well, we're trying to + +compute the expectation of +x plus y and this is the + +conditional PDF of y, not of the +random variable, x plus y. + +But I claim that we're OK, this +is still useful, because + +if we're conditioning +on x, this x + +just acts as a constant. + +It's not really going to change +anything except shift + +the expectation of y +by an amount of x. + +So what I'm saying in math terms +is that this is actually + +just x plus the expectation +of y given x. + +And now our conditional +PDF comes into play. + +Conditioned on x, this +is the PDF of y. + +And because it's uniformly +distributed and because + +expectation acts like center +of mass, we know that the + +expectation should be +the midpoint, right? + +And so to compute this point, we +simply take the average of + +the endpoints, x plus 1 plus +x over 2, which gives us + +2x plus 1 over 2. + +So plugging this back up here, +we get 2x/2 plus 2x plus 1 + +over 2, which is 4x plus 1 +over 2, or 2x plus 1/2. + +OK. + +So now I want to look at the +next term, the next inner + +term, which is this guy. + +So this computation is +going to be very + +similar in nature, actually. + +So we already discussed +that the joint-- + +sorry, not the joint, the +conditional PDF of y given x + +is this guy. + +So the variance of x plus y +conditioned on x, we sort of + +have a similar phenomenon +occurring. + +x now in this conditional +world just acts like a + +constant that shifts the PDF but +doesn't change the width + +of the distribution at all. + +So this is actually just equal +to the variance of y given x, + +because constants don't +affect the variance. + +And now we can look at this +conditional PDF to figure out + +what this is. + +So we're going to take a quick +tangent over here, and I'm + +just going to remind you guys +that we have a formula for + +computing the variance of a +random variable when it's + +uniformly distributed between +two endpoints. + +So say we have a random variable +whose PDF looks + +something like this. + +Let's call it, let's say, w. + +This is pww. + +We have a formula that says +variance of w is equal to b + +minus a squared over 12. + +So we can apply that +formula over here. + +b is x plus 1, a is x. + +So b minus a squared over +12 is just 1/12. + +So we get 1/12. + +So we're making good progress, +because we have this inner + +quantity and this +inner quantity. + +So now all we need to do is take +the outer variance and + +the outer expectation. + +So writing this all down, we +get variance of x plus y is + +equal to variance of this guy, +2x plus 1/2 plus the + +expectation of 1/12. + + + +So this term is quite simple. + +We know that the expectation of +a constant or of a scalar + +is simply that scalar. + +So this evaluates to 1/12. + +And this one is not +bad either. + +So similar to our discussion up +here, we know constants do + +not affect variance. + +You know they shift your +distribution, they don't + +change the variance. + +So we can ignore the 1/2. + +This scaling factor +of 2, however, + +will change the variance. + +But we know how to handle +this already + +from previous lectures. + +We know that you can just take +out this scalar scaling factor + +as long as we square it. + +So this becomes 2 squared, +or 4 times the + +variance of x plus 1/12. + +And now to compute the variance +of x, we're going to + +use that formula again, +and we're + +going to use this picture. + +So here we have the joint PDF of +x and y, but really we want + +now the PDF of x, so we +can figure out what + +the variance is. + +So hopefully you remember a +trick we taught you called + +marginalization. + +To get the PDF of x given +a joint PDF, you simply + +marginalize over the +values of y. + +So if you freeze x is equal to +0, you get the probability + +density line over x by +integrating over this + +interval, over y. + +So if you integrate over +this strip, you get 1. + +If you move x over a little +bit and you integrate over + +this strip, you get 1. + +This is the argument I was +making earlier that the width + +of this interval stays the same, +and hence, the variance + +stays the same. + +So based on that argument, which +was slightly hand wavy, + +let's come over here +and draw it. + + + +We're claiming that the PDF of +x, px of x, looks like this. + +It's just uniformly distributed +between 0 and 1. + +And if you buy that, then we're +done, we're home free, + +because we can apply this +formula, b minus a squared + +over 12, gives us +the variance. + +So b is 1, a is 0, which +gives variance of + +x is equal to 1/12. + +So coming back over here, we +get 4 times 1/12 plus 1/12, + +which is 5/12. + +And that is our answer. + +So this problem was +straightforward in the sense + +that our task was very clear. + +We had to compute this, and we +had to do so by using the law + +of total variance. + +But we sort of reviewed a lot +of concepts along the way. + +We saw how, given a joint +PDF, you marginalize to + +get the PDF of x. + +We saw how constants don't +change variance. + +We got a lot of practice +finding conditional + +distributions and computing +conditional + +expectations and variances. + +And we also saw this trick. + +And it might seem like cheating +to memorize formulas, + +but there's a few important +ones you should know. + +And it will help you sort of +become faster at doing + +computations. + +And that's important, +especially if you + +guys take the exams. + +So that's it. + +See you next time. \ No newline at end of file diff --git a/DF9fniCnL10.txt b/DF9fniCnL10.txt new file mode 100644 index 0000000000000000000000000000000000000000..20ff87161a344dc88ada679e01510bbb8a78e623 --- /dev/null +++ b/DF9fniCnL10.txt @@ -0,0 +1,8331 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license + + align:start position:0% +a Creative Commons license + + + align:start position:0% +a Creative Commons license +your support will help MIT + + align:start position:0% +your support will help MIT + + + align:start position:0% +your support will help MIT +OpenCourseWare continue to offer high + + align:start position:0% +OpenCourseWare continue to offer high + + + align:start position:0% +OpenCourseWare continue to offer high +quality educational resources for free + + align:start position:0% +quality educational resources for free + + + align:start position:0% +quality educational resources for free +to make a donation or view additional + + align:start position:0% +to make a donation or view additional + + + align:start position:0% +to make a donation or view additional +materials from hundreds of MIT courses + + align:start position:0% +materials from hundreds of MIT courses + + + align:start position:0% +materials from hundreds of MIT courses +visit MIT opencourseware at ocw.mit.edu + + align:start position:0% + + + + align:start position:0% + +so yeah so the publisher can demand you + + align:start position:0% +so yeah so the publisher can demand you + + + align:start position:0% +so yeah so the publisher can demand you +know I want to see this feature EA + + align:start position:0% +know I want to see this feature EA + + + align:start position:0% +know I want to see this feature EA +demands that this game work with origin + + align:start position:0% +demands that this game work with origin + + + align:start position:0% +demands that this game work with origin +ubisoft demands that you do play with + + align:start position:0% +ubisoft demands that you do play with + + + align:start position:0% +ubisoft demands that you do play with +that was that their Universal sign up + + align:start position:0% +that was that their Universal sign up + + + align:start position:0% +that was that their Universal sign up +system gets added odd things like that + + align:start position:0% +system gets added odd things like that + + + align:start position:0% +system gets added odd things like that +right that happens all the time other + + align:start position:0% +right that happens all the time other + + + align:start position:0% +right that happens all the time other +stuff that's maybe money related or + + align:start position:0% +stuff that's maybe money related or + + + align:start position:0% +stuff that's maybe money related or +market related plus light expectations + + align:start position:0% +market related plus light expectations + + + align:start position:0% +market related plus light expectations +just yeah that usually is similar to the + + align:start position:0% +just yeah that usually is similar to the + + + align:start position:0% +just yeah that usually is similar to the +publisher thing someone's got to push + + align:start position:0% +publisher thing someone's got to push + + + align:start position:0% +publisher thing someone's got to push +that but somebody could come internally + + align:start position:0% +that but somebody could come internally + + + align:start position:0% +that but somebody could come internally +from it from your developer from the + + align:start position:0% +from it from your developer from the + + + align:start position:0% +from it from your developer from the +development team right they look at + + align:start position:0% +development team right they look at + + + align:start position:0% +development team right they look at +competing products and says hey this + + align:start position:0% +competing products and says hey this + + + align:start position:0% +competing products and says hey this +thing seems to be doing well + + align:start position:0% +thing seems to be doing well + + + align:start position:0% +thing seems to be doing well +and I'll let that hats because hats seem + + align:start position:0% +and I'll let that hats because hats seem + + + align:start position:0% +and I'll let that hats because hats seem +to be doing well for some games so you + + align:start position:0% +to be doing well for some games so you + + + align:start position:0% +to be doing well for some games so you +know we can add hands to our game it's + + align:start position:0% +know we can add hands to our game it's + + + align:start position:0% +know we can add hands to our game it's +not going to necessarily change the way + + align:start position:0% +not going to necessarily change the way + + + align:start position:0% +not going to necessarily change the way +how to give functions better so a new + + align:start position:0% +how to give functions better so a new + + + align:start position:0% +how to give functions better so a new +feature is still a new you still got to + + align:start position:0% +feature is still a new you still got to + + + align:start position:0% +feature is still a new you still got to +come up with mechanics to unlock new + + align:start position:0% +come up with mechanics to unlock new + + + align:start position:0% +come up with mechanics to unlock new +hats and equipped new hats and make sure + + align:start position:0% +hats and equipped new hats and make sure + + + align:start position:0% +hats and equipped new hats and make sure +the enemy correctly and things like that + + align:start position:0% +the enemy correctly and things like that + + + align:start position:0% +the enemy correctly and things like that +even if necessarily the gameplay + + align:start position:0% +even if necessarily the gameplay + + + align:start position:0% +even if necessarily the gameplay +decision making you're making the game + + align:start position:0% +decision making you're making the game + + + align:start position:0% +decision making you're making the game +doesn't change of course hat certainly + + align:start position:0% +doesn't change of course hat certainly + + + align:start position:0% +doesn't change of course hat certainly +do change the way how some games work + + align:start position:0% +do change the way how some games work + + + align:start position:0% +do change the way how some games work +the changes in marketplace in general + + align:start position:0% +the changes in marketplace in general + + + align:start position:0% +the changes in marketplace in general +and sometimes are making a sequel to a + + align:start position:0% +and sometimes are making a sequel to a + + + align:start position:0% +and sometimes are making a sequel to a +game right sometimes you you you've got + + align:start position:0% +game right sometimes you you you've got + + + align:start position:0% +game right sometimes you you you've got +your adding number two or number three + + align:start position:0% +your adding number two or number three + + + align:start position:0% +your adding number two or number three +at the end of the title and your players + + align:start position:0% +at the end of the title and your players + + + align:start position:0% +at the end of the title and your players +are gonna expect something new and so + + align:start position:0% +are gonna expect something new and so + + + align:start position:0% +are gonna expect something new and so +there's some pressure for you to sort of + + align:start position:0% +there's some pressure for you to sort of + + + align:start position:0% +there's some pressure for you to sort of +add new mechanics instead of simply say + + align:start position:0% +add new mechanics instead of simply say + + + align:start position:0% +add new mechanics instead of simply say +iterating on the old ones why would you + + align:start position:0% +iterating on the old ones why would you + + + align:start position:0% +iterating on the old ones why would you +cut cut mechanics not necessarily + + align:start position:0% +cut cut mechanics not necessarily + + + align:start position:0% +cut cut mechanics not necessarily +cutting features but cutting mechanics + + align:start position:0% +cutting features but cutting mechanics + + + align:start position:0% +cutting features but cutting mechanics +game mechanics + + align:start position:0% + + + + align:start position:0% + +that's one that's one good reason I've + + align:start position:0% +that's one that's one good reason I've + + + align:start position:0% +that's one that's one good reason I've +been drilling into you all semester long + + align:start position:0% + + + + align:start position:0% + +decreasing Curtis I know this separate + + align:start position:0% +decreasing Curtis I know this separate + + + align:start position:0% +decreasing Curtis I know this separate +from simple if I gave they both both + + align:start position:0% +from simple if I gave they both both + + + align:start position:0% +from simple if I gave they both both +good points right there all the + + align:start position:0% +good points right there all the + + + align:start position:0% +good points right there all the +decreasing learned learning curve is + + align:start position:0% +decreasing learned learning curve is + + + align:start position:0% +decreasing learned learning curve is +like testers just don't get how this + + align:start position:0% +like testers just don't get how this + + + align:start position:0% +like testers just don't get how this +game functions because too much stuff + + align:start position:0% +game functions because too much stuff + + + align:start position:0% +game functions because too much stuff +going on simultaneously + + align:start position:0% +going on simultaneously + + + align:start position:0% +going on simultaneously +you could try to tune those mechanics to + + align:start position:0% +you could try to tune those mechanics to + + + align:start position:0% +you could try to tune those mechanics to +make it a little bit more legible if you + + align:start position:0% +make it a little bit more legible if you + + + align:start position:0% +make it a little bit more legible if you +just try taking mechanics completely out + + align:start position:0% +just try taking mechanics completely out + + + align:start position:0% +just try taking mechanics completely out +so that people can achieve it simplify + + align:start position:0% +so that people can achieve it simplify + + + align:start position:0% +so that people can achieve it simplify +any game could could be that but it also + + align:start position:0% +any game could could be that but it also + + + align:start position:0% +any game could could be that but it also +could be just trying to make what score + + align:start position:0% +could be just trying to make what score + + + align:start position:0% +could be just trying to make what score +about the game more obvious you know + + align:start position:0% +about the game more obvious you know + + + align:start position:0% +about the game more obvious you know +this game is really about generations + + align:start position:0% +this game is really about generations + + + align:start position:0% +this game is really about generations +and generations of heroes you know that + + align:start position:0% +and generations of heroes you know that + + + align:start position:0% +and generations of heroes you know that +there's a game by hero generators yeah + + align:start position:0% +there's a game by hero generators yeah + + + align:start position:0% +there's a game by hero generators yeah +and and you want you know and you've got + + align:start position:0% +and and you want you know and you've got + + + align:start position:0% +and and you want you know and you've got +say some sort of very elaborate weapons + + align:start position:0% +say some sort of very elaborate weapons + + + align:start position:0% +say some sort of very elaborate weapons +crafting mechanic or something like in + + align:start position:0% +crafting mechanic or something like in + + + align:start position:0% +crafting mechanic or something like in +there well the weapons crafty mechanic + + align:start position:0% +there well the weapons crafty mechanic + + + align:start position:0% +there well the weapons crafty mechanic +may not be really what your games about + + align:start position:0% +may not be really what your games about + + + align:start position:0% +may not be really what your games about +so you might want to take that out + + align:start position:0% +so you might want to take that out + + + align:start position:0% +so you might want to take that out +because people saw forget about what the + + align:start position:0% +because people saw forget about what the + + + align:start position:0% +because people saw forget about what the +core experience of the game is supposed + + align:start position:0% +core experience of the game is supposed + + + align:start position:0% +core experience of the game is supposed +to be so focusing back on the core of + + align:start position:0% +to be so focusing back on the core of + + + align:start position:0% +to be so focusing back on the core of +the game what else + + align:start position:0% + + + + align:start position:0% + +say okay well all new new technologies + + align:start position:0% +say okay well all new new technologies + + + align:start position:0% +say okay well all new new technologies +come out like what physics you know + + align:start position:0% +come out like what physics you know + + + align:start position:0% +come out like what physics you know +maybe + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +well that's true right I tried to think + + align:start position:0% +well that's true right I tried to think + + + align:start position:0% +well that's true right I tried to think +of a game what that's a really obvious + + align:start position:0% +of a game what that's a really obvious + + + align:start position:0% +of a game what that's a really obvious +example can I want to think of a game + + align:start position:0% +example can I want to think of a game + + + align:start position:0% +example can I want to think of a game +mechanic that substantially changed when + + align:start position:0% +mechanic that substantially changed when + + + align:start position:0% +mechanic that substantially changed when +it went from 2d to 3d I'm thinking Mario + + align:start position:0% +it went from 2d to 3d I'm thinking Mario + + + align:start position:0% +it went from 2d to 3d I'm thinking Mario +but just just played on movement + + align:start position:0% +but just just played on movement + + + align:start position:0% +but just just played on movement +well the way how the camera responds to + + align:start position:0% +well the way how the camera responds to + + + align:start position:0% +well the way how the camera responds to +movement as well that that's that's a + + align:start position:0% +movement as well that that's that's a + + + align:start position:0% +movement as well that that's that's a +big one right in a 2d game say a + + align:start position:0% +big one right in a 2d game say a + + + align:start position:0% +big one right in a 2d game say a +side-scrolling game like Metroid or + + align:start position:0% +side-scrolling game like Metroid or + + + align:start position:0% +side-scrolling game like Metroid or +something like that + + align:start position:0% +something like that + + + align:start position:0% +something like that +you don't have this situation where the + + align:start position:0% +you don't have this situation where the + + + align:start position:0% +you don't have this situation where the +place where you are trying to go to is + + align:start position:0% +place where you are trying to go to is + + + align:start position:0% +place where you are trying to go to is +obscured unless it's actually physically + + align:start position:0% +obscured unless it's actually physically + + + align:start position:0% +obscured unless it's actually physically +blocked by something now you have to + + align:start position:0% +blocked by something now you have to + + + align:start position:0% +blocked by something now you have to +destroy or open up or something and in a + + align:start position:0% +destroy or open up or something and in a + + + align:start position:0% +destroy or open up or something and in a +3d space you that happens all the time + + align:start position:0% +3d space you that happens all the time + + + align:start position:0% +3d space you that happens all the time +you know you've just got bits of + + align:start position:0% +you know you've just got bits of + + + align:start position:0% +you know you've just got bits of +background scenery getting in a way off + + align:start position:0% +background scenery getting in a way off + + + align:start position:0% +background scenery getting in a way off +the camera Mario just changed the way + + align:start position:0% +the camera Mario just changed the way + + + align:start position:0% +the camera Mario just changed the way +how jumps work entirely when he went + + align:start position:0% +how jumps work entirely when he went + + + align:start position:0% +how jumps work entirely when he went +from the 2d Mario's to the Super Mario + + align:start position:0% +from the 2d Mario's to the Super Mario + + + align:start position:0% +from the 2d Mario's to the Super Mario +64 and they added and every iteration on + + align:start position:0% +64 and they added and every iteration on + + + align:start position:0% +64 and they added and every iteration on +top of that has added new ways to jump + + align:start position:0% +top of that has added new ways to jump + + + align:start position:0% +top of that has added new ways to jump +double jump struggle jumps jumping off + + align:start position:0% +double jump struggle jumps jumping off + + + align:start position:0% +double jump struggle jumps jumping off +the wall and stuff at it now now the + + align:start position:0% +the wall and stuff at it now now the + + + align:start position:0% +the wall and stuff at it now now the +latest Mario gives expect that you know + + align:start position:0% +latest Mario gives expect that you know + + + align:start position:0% +latest Mario gives expect that you know +all of that which is why I can't play + + align:start position:0% +all of that which is why I can't play + + + align:start position:0% +all of that which is why I can't play +Mario anymore because I didn't go + + align:start position:0% +Mario anymore because I didn't go + + + align:start position:0% +Mario anymore because I didn't go +through that process although the games + + align:start position:0% +through that process although the games + + + align:start position:0% +through that process although the games +are not at least the first couple of + + align:start position:0% +are not at least the first couple of + + + align:start position:0% +are not at least the first couple of +levels are not that harsh let's see what + + align:start position:0% +levels are not that harsh let's see what + + + align:start position:0% +levels are not that harsh let's see what +else this one I've been always + + align:start position:0% +else this one I've been always + + + align:start position:0% +else this one I've been always +mentioning there's an entire semester + + align:start position:0% + + + + align:start position:0% + +just to try something yeah oh yeah yeah + + align:start position:0% +just to try something yeah oh yeah yeah + + + align:start position:0% +just to try something yeah oh yeah yeah +justjust just to see how he's gonna + + align:start position:0% +justjust just to see how he's gonna + + + align:start position:0% +justjust just to see how he's gonna +change how the gameplay works right you + + align:start position:0% +change how the gameplay works right you + + + align:start position:0% +change how the gameplay works right you +know it is let's take something out and + + align:start position:0% +know it is let's take something out and + + + align:start position:0% +know it is let's take something out and +see whether that was actually essential + + align:start position:0% +see whether that was actually essential + + + align:start position:0% +see whether that was actually essential +to the experience or maybe I was getting + + align:start position:0% +to the experience or maybe I was getting + + + align:start position:0% +to the experience or maybe I was getting +in way of the experience you don't know + + align:start position:0% +in way of the experience you don't know + + + align:start position:0% +in way of the experience you don't know +you know like the emergent results of + + align:start position:0% +you know like the emergent results of + + + align:start position:0% +you know like the emergent results of +taking out a mechanic might actually end + + align:start position:0% +taking out a mechanic might actually end + + + align:start position:0% +taking out a mechanic might actually end +up as more like more interesting + + align:start position:0% +up as more like more interesting + + + align:start position:0% +up as more like more interesting +experience one of one thing that a book + + align:start position:0% +experience one of one thing that a book + + + align:start position:0% +experience one of one thing that a book +does mentioned is to take stuff out that + + align:start position:0% +does mentioned is to take stuff out that + + + align:start position:0% +does mentioned is to take stuff out that +might actually change to the ESRB rating + + align:start position:0% +might actually change to the ESRB rating + + + align:start position:0% +might actually change to the ESRB rating +of your game or the PEGI rating + + align:start position:0% +of your game or the PEGI rating + + + align:start position:0% +of your game or the PEGI rating +understanding something in the UK or in + + align:start position:0% +understanding something in the UK or in + + + align:start position:0% +understanding something in the UK or in +Europe so for instance if your game if + + align:start position:0% +Europe so for instance if your game if + + + align:start position:0% +Europe so for instance if your game if +you had if you're building the top of + + align:start position:0% +you had if you're building the top of + + + align:start position:0% +you had if you're building the top of +the game engine like unreal or something + + align:start position:0% +the game engine like unreal or something + + + align:start position:0% +the game engine like unreal or something +like that which has body body location + + align:start position:0% +like that which has body body location + + + align:start position:0% +like that which has body body location +damage if you shoot a head you know the + + align:start position:0% +damage if you shoot a head you know the + + + align:start position:0% +damage if you shoot a head you know the +game knows that it that you shot the + + align:start position:0% +game knows that it that you shot the + + + align:start position:0% +game knows that it that you shot the +head but maybe you don't want your game + + align:start position:0% +head but maybe you don't want your game + + + align:start position:0% +head but maybe you don't want your game +to be that specific + + align:start position:0% +to be that specific + + + align:start position:0% +to be that specific +maybe you're designing a game for kids + + align:start position:0% +maybe you're designing a game for kids + + + align:start position:0% +maybe you're designing a game for kids +or something like that and it's like oh + + align:start position:0% +or something like that and it's like oh + + + align:start position:0% +or something like that and it's like oh +you wanting kids for a hitch for + + align:start position:0% +you wanting kids for a hitch for + + + align:start position:0% +you wanting kids for a hitch for +successfully head-chopping each other is + + align:start position:0% +successfully head-chopping each other is + + + align:start position:0% +successfully head-chopping each other is +maybe not lit feel that we want to go + + align:start position:0% +maybe not lit feel that we want to go + + + align:start position:0% +maybe not lit feel that we want to go +for I initially put sense push us into + + align:start position:0% +for I initially put sense push us into + + + align:start position:0% +for I initially put sense push us into +out of the E for Everyone and into + + align:start position:0% +out of the E for Everyone and into + + + align:start position:0% +out of the E for Everyone and into +what's what's what's the next way mt t + + align:start position:0% +what's what's what's the next way mt t + + + align:start position:0% +what's what's what's the next way mt t +yeah ye 10 rating is that used to be + + align:start position:0% +yeah ye 10 rating is that used to be + + + align:start position:0% +yeah ye 10 rating is that used to be +okay and sometimes you just gotta cut + + align:start position:0% +okay and sometimes you just gotta cut + + + align:start position:0% +okay and sometimes you just gotta cut +mechanics because you don't have time to + + align:start position:0% +mechanics because you don't have time to + + + align:start position:0% +mechanics because you don't have time to +do them they're great ideas they both + + align:start position:0% +do them they're great ideas they both + + + align:start position:0% +do them they're great ideas they both +actually make your game better if you + + align:start position:0% +actually make your game better if you + + + align:start position:0% +actually make your game better if you +had time to be able to polish them and + + align:start position:0% +had time to be able to polish them and + + + align:start position:0% +had time to be able to polish them and +make them understandable and smooth and + + align:start position:0% +make them understandable and smooth and + + + align:start position:0% +make them understandable and smooth and +everything they just find out all times + + align:start position:0% +everything they just find out all times + + + align:start position:0% +everything they just find out all times +and you just want to be able to ship so + + align:start position:0% +and you just want to be able to ship so + + + align:start position:0% +and you just want to be able to ship so +that's a perfectly legitimate + + align:start position:0% +that's a perfectly legitimate + + + align:start position:0% +that's a perfectly legitimate +consideration oh so so that that's this + + align:start position:0% +consideration oh so so that that's this + + + align:start position:0% +consideration oh so so that that's this +process of like generating ideas so you + + align:start position:0% +process of like generating ideas so you + + + align:start position:0% +process of like generating ideas so you +say say this is like an axis of my the + + align:start position:0% +say say this is like an axis of my the + + + align:start position:0% +say say this is like an axis of my the +number of ideas that you've got in your + + align:start position:0% +number of ideas that you've got in your + + + align:start position:0% +number of ideas that you've got in your +game and mechanics in terms of either + + align:start position:0% +game and mechanics in terms of either + + + align:start position:0% +game and mechanics in terms of either +rules in a computer game of the code in + + align:start position:0% +rules in a computer game of the code in + + + align:start position:0% +rules in a computer game of the code in +these games let's just say it's rules as + + align:start position:0% +these games let's just say it's rules as + + + align:start position:0% +these games let's just say it's rules as +pieces for everything we have to make + + align:start position:0% +pieces for everything we have to make + + + align:start position:0% +pieces for everything we have to make +your game work and you kind of go + + align:start position:0% +your game work and you kind of go + + + align:start position:0% +your game work and you kind of go +through this brainstorming phase where + + align:start position:0% +through this brainstorming phase where + + + align:start position:0% +through this brainstorming phase where +you get like a ton of ideas right + + align:start position:0% +you get like a ton of ideas right + + + align:start position:0% +you get like a ton of ideas right +because some good ones up here cuz some + + align:start position:0% +because some good ones up here cuz some + + + align:start position:0% +because some good ones up here cuz some +crappy ones down there it's probably + + align:start position:0% +crappy ones down there it's probably + + + align:start position:0% +crappy ones down there it's probably +more like like a whole bunch of crappy + + align:start position:0% +more like like a whole bunch of crappy + + + align:start position:0% +more like like a whole bunch of crappy +ideas a couple of good ideas but you get + + align:start position:0% +ideas a couple of good ideas but you get + + + align:start position:0% +ideas a couple of good ideas but you get +this big explosion of ideas where where + + align:start position:0% +this big explosion of ideas where where + + + align:start position:0% +this big explosion of ideas where where +I use turning to experiments somebody my + + align:start position:0% +I use turning to experiments somebody my + + + align:start position:0% +I use turning to experiments somebody my +phone experiments they're thinking you + + align:start position:0% +phone experiments they're thinking you + + + align:start position:0% +phone experiments they're thinking you +know just just discussing them among + + align:start position:0% +know just just discussing them among + + + align:start position:0% +know just just discussing them among +your team what if we did this what if we + + align:start position:0% +your team what if we did this what if we + + + align:start position:0% +your team what if we did this what if we +did how we solve that problem we really + + align:start position:0% +did how we solve that problem we really + + + align:start position:0% +did how we solve that problem we really +be real interests of all experiments + + align:start position:0% +be real interests of all experiments + + + align:start position:0% +be real interests of all experiments +where you're something that you can play + + align:start position:0% +where you're something that you can play + + + align:start position:0% +where you're something that you can play +you know something that you whip up + + align:start position:0% +you know something that you whip up + + + align:start position:0% +you know something that you whip up +within an hour or half an hour and you + + align:start position:0% +within an hour or half an hour and you + + + align:start position:0% +within an hour or half an hour and you +actually put it in front we've been + + align:start position:0% +actually put it in front we've been + + + align:start position:0% +actually put it in front we've been +doing that all all semester some of the + + align:start position:0% +doing that all all semester some of the + + + align:start position:0% +doing that all all semester some of the +ideas we just come up off you know + + align:start position:0% +ideas we just come up off you know + + + align:start position:0% +ideas we just come up off you know +different ideas interacting and says + + align:start position:0% +different ideas interacting and says + + + align:start position:0% +different ideas interacting and says +what if we had you know dogs in our game + + align:start position:0% +what if we had you know dogs in our game + + + align:start position:0% +what if we had you know dogs in our game +what if we had solar power and game what + + align:start position:0% +what if we had solar power and game what + + + align:start position:0% +what if we had solar power and game what +every day has solar powered talks about + + align:start position:0% +every day has solar powered talks about + + + align:start position:0% +every day has solar powered talks about +game it things like that you know and + + align:start position:0% +game it things like that you know and + + + align:start position:0% +game it things like that you know and +then I guess just happened um however + + align:start position:0% +then I guess just happened um however + + + align:start position:0% +then I guess just happened um however +it's important that's so fun sort of in + + align:start position:0% +it's important that's so fun sort of in + + + align:start position:0% +it's important that's so fun sort of in +describing the brainstorming process + + align:start position:0% +describing the brainstorming process + + + align:start position:0% +describing the brainstorming process +that you can all been through already + + align:start position:0% +that you can all been through already + + + align:start position:0% +that you can all been through already +but one thing that we haven't + + align:start position:0% +but one thing that we haven't + + + align:start position:0% +but one thing that we haven't +necessarily asked you to do nearly as + + align:start position:0% +necessarily asked you to do nearly as + + + align:start position:0% +necessarily asked you to do nearly as +much is to come up with heart with with + + align:start position:0% +much is to come up with heart with with + + + align:start position:0% +much is to come up with heart with with +actual discrete experiments and I was + + align:start position:0% +actual discrete experiments and I was + + + align:start position:0% +actual discrete experiments and I was +like here's an idea actually come up + + align:start position:0% +like here's an idea actually come up + + + align:start position:0% +like here's an idea actually come up +with a criteria of success that you're + + align:start position:0% +with a criteria of success that you're + + + align:start position:0% +with a criteria of success that you're +looking for how do we know whether this + + align:start position:0% +looking for how do we know whether this + + + align:start position:0% +looking for how do we know whether this +particular idea this particular + + align:start position:0% +particular idea this particular + + + align:start position:0% +particular idea this particular +experiment version of the idea is + + align:start position:0% +experiment version of the idea is + + + align:start position:0% +experiment version of the idea is +succeeding or not and you're going to + + align:start position:0% +succeeding or not and you're going to + + + align:start position:0% +succeeding or not and you're going to +need that because you're going to need + + align:start position:0% +need that because you're going to need + + + align:start position:0% +need that because you're going to need +to call yeah you're gonna need to like + + align:start position:0% +to call yeah you're gonna need to like + + + align:start position:0% +to call yeah you're gonna need to like +reduce this back down try to keep this + + align:start position:0% +reduce this back down try to keep this + + + align:start position:0% +reduce this back down try to keep this +or maybe even build this up a little bit + + align:start position:0% +or maybe even build this up a little bit + + + align:start position:0% +or maybe even build this up a little bit +actually springing ball like you're + + align:start position:0% +actually springing ball like you're + + + align:start position:0% +actually springing ball like you're +going to come + + align:start position:0% +going to come + + + align:start position:0% +going to come +then you wonder brace yourself up again + + align:start position:0% +then you wonder brace yourself up again + + + align:start position:0% +then you wonder brace yourself up again +and each time each time discuss you have + + align:start position:0% +and each time each time discuss you have + + + align:start position:0% +and each time each time discuss you have +kind of an increase of bad idea you'll + + align:start position:0% +kind of an increase of bad idea you'll + + + align:start position:0% +kind of an increase of bad idea you'll +have increase and bad ideas but decrease + + align:start position:0% +have increase and bad ideas but decrease + + + align:start position:0% +have increase and bad ideas but decrease +of bad ideas but your total number of + + align:start position:0% +of bad ideas but your total number of + + + align:start position:0% +of bad ideas but your total number of +good ideas just keep going on right am i + + align:start position:0% +good ideas just keep going on right am i + + + align:start position:0% +good ideas just keep going on right am i +good I'm using a very big term it could + + align:start position:0% +good I'm using a very big term it could + + + align:start position:0% +good I'm using a very big term it could +be it could be polished it could mean + + align:start position:0% +be it could be polished it could mean + + + align:start position:0% +be it could be polished it could mean +actually good for gameplay it could mean + + align:start position:0% +actually good for gameplay it could mean + + + align:start position:0% +actually good for gameplay it could mean +you know something that's been proven in + + align:start position:0% +you know something that's been proven in + + + align:start position:0% +you know something that's been proven in +the marketplace something desirable that + + align:start position:0% +the marketplace something desirable that + + + align:start position:0% +the marketplace something desirable that +you want to keep in a game things it + + align:start position:0% +you want to keep in a game things it + + + align:start position:0% +you want to keep in a game things it +could be like it should be good for the + + align:start position:0% +could be like it should be good for the + + + align:start position:0% +could be like it should be good for the +core experience one of the problems + + align:start position:0% +core experience one of the problems + + + align:start position:0% +core experience one of the problems +could be they are just they're good + + align:start position:0% +could be they are just they're good + + + align:start position:0% +could be they are just they're good +working mechanics let's see that dark up + + align:start position:0% +working mechanics let's see that dark up + + + align:start position:0% +working mechanics let's see that dark up +there are a couple of agents even in + + align:start position:0% +there are a couple of agents even in + + + align:start position:0% +there are a couple of agents even in +this early brainstorming process so I'm + + align:start position:0% +this early brainstorming process so I'm + + + align:start position:0% +this early brainstorming process so I'm +just looking at this just this yeah Oh + + align:start position:0% +just looking at this just this yeah Oh + + + align:start position:0% +just looking at this just this yeah Oh +what is that you pretty much already + + align:start position:0% +what is that you pretty much already + + + align:start position:0% +what is that you pretty much already +think you already know what game I'm + + align:start position:0% +think you already know what game I'm + + + align:start position:0% +think you already know what game I'm +gonna make you call a single solution + + align:start position:0% +gonna make you call a single solution + + + align:start position:0% +gonna make you call a single solution +you know say say you're taking the + + align:start position:0% +you know say say you're taking the + + + align:start position:0% +you know say say you're taking the +computer game version of this class and + + align:start position:0% +computer game version of this class and + + + align:start position:0% +computer game version of this class and +you decide that you're going to make an + + align:start position:0% +you decide that you're going to make an + + + align:start position:0% +you decide that you're going to make an +RPG and your model is Final Fantasy 6 ok + + align:start position:0% +RPG and your model is Final Fantasy 6 ok + + + align:start position:0% +RPG and your model is Final Fantasy 6 ok +so everything is going to basically + + align:start position:0% +so everything is going to basically + + + align:start position:0% +so everything is going to basically +follow the Final Fantasy 6 template so + + align:start position:0% +follow the Final Fantasy 6 template so + + + align:start position:0% +follow the Final Fantasy 6 template so +you're basically pursuing one single + + align:start position:0% +you're basically pursuing one single + + + align:start position:0% +you're basically pursuing one single +solution and the problem with that is + + align:start position:0% +solution and the problem with that is + + + align:start position:0% +solution and the problem with that is +that your implementation ability of + + align:start position:0% +that your implementation ability of + + + align:start position:0% +that your implementation ability of +actually making all of those things fit + + align:start position:0% +actually making all of those things fit + + + align:start position:0% +actually making all of those things fit +that template is already not you are not + + align:start position:0% +that template is already not you are not + + + align:start position:0% +that template is already not you are not +square right you you you don't have all + + align:start position:0% +square right you you you don't have all + + + align:start position:0% +square right you you you don't have all +the resources that Square had even back + + align:start position:0% +the resources that Square had even back + + + align:start position:0% +the resources that Square had even back +in Final Fantasy 6 schema how old is + + align:start position:0% +in Final Fantasy 6 schema how old is + + + align:start position:0% +in Final Fantasy 6 schema how old is +Final Fantasy 6 1994 2 + + align:start position:0% +Final Fantasy 6 1994 2 + + + align:start position:0% +Final Fantasy 6 1994 2 +something like that I mean even then + + align:start position:0% +something like that I mean even then + + + align:start position:0% +something like that I mean even then +they were a large team with many years + + align:start position:0% +they were a large team with many years + + + align:start position:0% +they were a large team with many years +to work on on at least many at least a + + align:start position:0% +to work on on at least many at least a + + + align:start position:0% +to work on on at least many at least a +year to work on the game I don't know + + align:start position:0% +year to work on the game I don't know + + + align:start position:0% +year to work on the game I don't know +how long they actually worked on that + + align:start position:0% +how long they actually worked on that + + + align:start position:0% +how long they actually worked on that +game it's very very good chance that + + align:start position:0% +game it's very very good chance that + + + align:start position:0% +game it's very very good chance that +your that your ability to actually even + + align:start position:0% +your that your ability to actually even + + + align:start position:0% +your that your ability to actually even +implement something that you know how it + + align:start position:0% +implement something that you know how it + + + align:start position:0% +implement something that you know how it +already works may not be able to meet + + align:start position:0% +already works may not be able to meet + + + align:start position:0% +already works may not be able to meet +that so you will have a failed + + align:start position:0% +that so you will have a failed + + + align:start position:0% +that so you will have a failed +experiment and then you're kind of stuck + + align:start position:0% +experiment and then you're kind of stuck + + + align:start position:0% +experiment and then you're kind of stuck +you don't know what to do so you're + + align:start position:0% +you don't know what to do so you're + + + align:start position:0% +you don't know what to do so you're +gonna have to do lots and lots of + + align:start position:0% +gonna have to do lots and lots of + + + align:start position:0% +gonna have to do lots and lots of +experiments um + + align:start position:0% +experiments um + + + align:start position:0% +experiments um +but experiments are expensive everything + + align:start position:0% +but experiments are expensive everything + + + align:start position:0% +but experiments are expensive everything +takes time and everything is going to + + align:start position:0% +takes time and everything is going to + + + align:start position:0% +takes time and everything is going to +need culling + + align:start position:0% +need culling + + + align:start position:0% +need culling +at some point of time and which needs a + + align:start position:0% +at some point of time and which needs a + + + align:start position:0% +at some point of time and which needs a +certain amount of time that isn't going + + align:start position:0% +certain amount of time that isn't going + + + align:start position:0% +certain amount of time that isn't going +to end up going into making this this + + align:start position:0% +to end up going into making this this + + + align:start position:0% +to end up going into making this this +chunk actually went into discharge which + + align:start position:0% +chunk actually went into discharge which + + + align:start position:0% +chunk actually went into discharge which +is why we've been trying to teach you + + align:start position:0% +is why we've been trying to teach you + + + align:start position:0% +is why we've been trying to teach you +how to prototype really really quickly + + align:start position:0% +how to prototype really really quickly + + + align:start position:0% +how to prototype really really quickly +it's a little bit of a recap because we + + align:start position:0% +it's a little bit of a recap because we + + + align:start position:0% +it's a little bit of a recap because we +want you to try to be able to get out to + + align:start position:0% +want you to try to be able to get out to + + + align:start position:0% +want you to try to be able to get out to +experiments + + align:start position:0% +experiments + + + align:start position:0% +experiments +come to a conclusion about whether that + + align:start position:0% +come to a conclusion about whether that + + + align:start position:0% +come to a conclusion about whether that +idea was good or not as fast as possible + + align:start position:0% +idea was good or not as fast as possible + + + align:start position:0% +idea was good or not as fast as possible +so that you kind of reduce the cost of + + align:start position:0% +so that you kind of reduce the cost of + + + align:start position:0% +so that you kind of reduce the cost of +doing a single experiment and yeah it's + + align:start position:0% +doing a single experiment and yeah it's + + + align:start position:0% +doing a single experiment and yeah it's +true that you're not going to be able to + + align:start position:0% +true that you're not going to be able to + + + align:start position:0% +true that you're not going to be able to +conduct an experiment on every single + + align:start position:0% +conduct an experiment on every single + + + align:start position:0% +conduct an experiment on every single +idea that you've got so you have to kind + + align:start position:0% +idea that you've got so you have to kind + + + align:start position:0% +idea that you've got so you have to kind +of pick and choose a select number of of + + align:start position:0% +of pick and choose a select number of of + + + align:start position:0% +of pick and choose a select number of of +ideas to be able to take to experimental + + align:start position:0% +ideas to be able to take to experimental + + + align:start position:0% +ideas to be able to take to experimental +experimental stage now there are a + + align:start position:0% +experimental stage now there are a + + + align:start position:0% +experimental stage now there are a +couple of things that you can look out + + align:start position:0% +couple of things that you can look out + + + align:start position:0% +couple of things that you can look out +for to say maybe we don't want to + + align:start position:0% +for to say maybe we don't want to + + + align:start position:0% +for to say maybe we don't want to +conduct an experiment or something one + + align:start position:0% +conduct an experiment or something one + + + align:start position:0% +conduct an experiment or something one +is a brittle idea and a better idea is + + align:start position:0% +is a brittle idea and a better idea is + + + align:start position:0% +is a brittle idea and a better idea is +that you kind of have to kind of twist + + align:start position:0% +that you kind of have to kind of twist + + + align:start position:0% +that you kind of have to kind of twist +it really really really hard to be able + + align:start position:0% +it really really really hard to be able + + + align:start position:0% +it really really really hard to be able +to make it fit with any idea that you've + + align:start position:0% +to make it fit with any idea that you've + + + align:start position:0% +to make it fit with any idea that you've +already got you know you I'm assuming + + align:start position:0% +already got you know you I'm assuming + + + align:start position:0% +already got you know you I'm assuming +that you've already got as a concept + + align:start position:0% +that you've already got as a concept + + + align:start position:0% +that you've already got as a concept +that your team was kind of build around + + align:start position:0% +that your team was kind of build around + + + align:start position:0% +that your team was kind of build around +this concept somebody comes up with an + + align:start position:0% +this concept somebody comes up with an + + + align:start position:0% +this concept somebody comes up with an +idea and there's a huge amount of + + align:start position:0% +idea and there's a huge amount of + + + align:start position:0% +idea and there's a huge amount of +twisting and turning to be able to even + + align:start position:0% +twisting and turning to be able to even + + + align:start position:0% +twisting and turning to be able to even +make it fit close even though you think + + align:start position:0% +make it fit close even though you think + + + align:start position:0% +make it fit close even though you think +that on its own this idea is a really + + align:start position:0% +that on its own this idea is a really + + + align:start position:0% +that on its own this idea is a really +good idea you might actually want to see + + align:start position:0% +good idea you might actually want to see + + + align:start position:0% +good idea you might actually want to see +how many different ways could this + + align:start position:0% +how many different ways could this + + + align:start position:0% +how many different ways could this +particular idea be executed before you + + align:start position:0% +particular idea be executed before you + + + align:start position:0% +particular idea be executed before you +actually decide on a weight or on an + + align:start position:0% +actually decide on a weight or on an + + + align:start position:0% +actually decide on a weight or on an +experiment to conduct on that idea two + + align:start position:0% +experiment to conduct on that idea two + + + align:start position:0% +experiment to conduct on that idea two +ways that you can do that one is + + align:start position:0% +ways that you can do that one is + + + align:start position:0% +ways that you can do that one is +you just specify you just spent + + align:start position:0% +you just specify you just spent + + + align:start position:0% +you just specify you just spent +specifying what is the goal of this + + align:start position:0% +specifying what is the goal of this + + + align:start position:0% +specifying what is the goal of this +possibly pretty right here right it + + align:start position:0% +possibly pretty right here right it + + + align:start position:0% +possibly pretty right here right it +takes a lot of testing why do we need + + align:start position:0% +takes a lot of testing why do we need + + + align:start position:0% +takes a lot of testing why do we need +this idea in the first place is it + + align:start position:0% +this idea in the first place is it + + + align:start position:0% +this idea in the first place is it +because the challenge in the game is too + + align:start position:0% +because the challenge in the game is too + + + align:start position:0% +because the challenge in the game is too +low + + align:start position:0% +low + + + align:start position:0% +low +is it because the players have too much + + align:start position:0% +is it because the players have too much + + + align:start position:0% +is it because the players have too much +information or not enough information + + align:start position:0% +information or not enough information + + + align:start position:0% +information or not enough information +about what they're supposed to do is it + + align:start position:0% +about what they're supposed to do is it + + + align:start position:0% +about what they're supposed to do is it +because you want to introduce a little + + align:start position:0% +because you want to introduce a little + + + align:start position:0% +because you want to introduce a little +element of chance or low or maybe setup + + align:start position:0% +element of chance or low or maybe setup + + + align:start position:0% +element of chance or low or maybe setup +give some sort of strategic + + align:start position:0% +give some sort of strategic + + + align:start position:0% +give some sort of strategic +decision-making try to identify what is + + align:start position:0% +decision-making try to identify what is + + + align:start position:0% +decision-making try to identify what is +this problem that you're trying to solve + + align:start position:0% +this problem that you're trying to solve + + + align:start position:0% +this problem that you're trying to solve +in the first place with this kind of + + align:start position:0% +in the first place with this kind of + + + align:start position:0% +in the first place with this kind of +unwieldy idea all right and once you'd + + align:start position:0% +unwieldy idea all right and once you'd + + + align:start position:0% +unwieldy idea all right and once you'd +be able to identify that then you come + + align:start position:0% +be able to identify that then you come + + + align:start position:0% +be able to identify that then you come +up with all right what are all the + + align:start position:0% +up with all right what are all the + + + align:start position:0% +up with all right what are all the +different ways that we could address + + align:start position:0% +different ways that we could address + + + align:start position:0% +different ways that we could address +that problem as opposed to here's this + + align:start position:0% +that problem as opposed to here's this + + + align:start position:0% +that problem as opposed to here's this +one solution is kind of unwieldy that + + align:start position:0% +one solution is kind of unwieldy that + + + align:start position:0% +one solution is kind of unwieldy that +words that might very well solve that + + align:start position:0% +words that might very well solve that + + + align:start position:0% +words that might very well solve that +problem but maybe there are alternatives + + align:start position:0% +problem but maybe there are alternatives + + + align:start position:0% +problem but maybe there are alternatives +has anyone encountered this in your own + + align:start position:0% +has anyone encountered this in your own + + + align:start position:0% +has anyone encountered this in your own +prototyping maybe this assignment maybe + + align:start position:0% +prototyping maybe this assignment maybe + + + align:start position:0% +prototyping maybe this assignment maybe +in a previous assignment like somebody + + align:start position:0% +in a previous assignment like somebody + + + align:start position:0% +in a previous assignment like somebody +had an idea that was just kind of hard + + align:start position:0% +had an idea that was just kind of hard + + + align:start position:0% +had an idea that was just kind of hard +to use but then twenty idea was tried to + + align:start position:0% +to use but then twenty idea was tried to + + + align:start position:0% +to use but then twenty idea was tried to +solve was actually a good problem to + + align:start position:0% +solve was actually a good problem to + + + align:start position:0% +solve was actually a good problem to +solve no not yet I thought it's awesome + + align:start position:0% +solve no not yet I thought it's awesome + + + align:start position:0% +solve no not yet I thought it's awesome +nuts if you've encountered it I'd love + + align:start position:0% +nuts if you've encountered it I'd love + + + align:start position:0% +nuts if you've encountered it I'd love +to get an example from one of you I can + + align:start position:0% +to get an example from one of you I can + + + align:start position:0% +to get an example from one of you I can +throw in it I can throw out examples but + + align:start position:0% +throw in it I can throw out examples but + + + align:start position:0% +throw in it I can throw out examples but +I'd love to be able to hear examples + + align:start position:0% +I'd love to be able to hear examples + + + align:start position:0% +I'd love to be able to hear examples +from one of you + + align:start position:0% + + + + align:start position:0% + +against our skin we noticed a couple + + align:start position:0% +against our skin we noticed a couple + + + align:start position:0% +against our skin we noticed a couple +problems with the game so he came up + + align:start position:0% +problems with the game so he came up + + + align:start position:0% +problems with the game so he came up +with various ways of trying to resolve + + align:start position:0% +with various ways of trying to resolve + + + align:start position:0% +with various ways of trying to resolve +it mmm that generally work for the game + + align:start position:0% +it mmm that generally work for the game + + + align:start position:0% +it mmm that generally work for the game +itself but solved the smaller problem + + align:start position:0% +itself but solved the smaller problem + + + align:start position:0% +itself but solved the smaller problem +okay be more specific about what the + + align:start position:0% +okay be more specific about what the + + + align:start position:0% +okay be more specific about what the +problem yes was that the way our game + + align:start position:0% +problem yes was that the way our game + + + align:start position:0% +problem yes was that the way our game +was with you know the Seneca tic-tac-toe + + align:start position:0% +was with you know the Seneca tic-tac-toe + + + align:start position:0% +was with you know the Seneca tic-tac-toe +it was really hard to see what what sets + + align:start position:0% +it was really hard to see what what sets + + + align:start position:0% +it was really hard to see what what sets +were available on the board right this + + align:start position:0% +were available on the board right this + + + align:start position:0% +were available on the board right this +was a set this up in the game sure yeah + + align:start position:0% +was a set this up in the game sure yeah + + + align:start position:0% +was a set this up in the game sure yeah +yeah and so one of these we tried to do + + align:start position:0% +yeah and so one of these we tried to do + + + align:start position:0% +yeah and so one of these we tried to do +was removing the center tile all + + align:start position:0% +was removing the center tile all + + + align:start position:0% +was removing the center tile all +together mmm so that you could only play + + align:start position:0% +together mmm so that you could only play + + + align:start position:0% +together mmm so that you could only play +around the edges which did solve the + + align:start position:0% +around the edges which did solve the + + + align:start position:0% +around the edges which did solve the +problem of now you can really see what + + align:start position:0% +problem of now you can really see what + + + align:start position:0% +problem of now you can really see what +everything was there's a lot easier in + + align:start position:0% +everything was there's a lot easier in + + + align:start position:0% +everything was there's a lot easier in +that sense except there's just a lot + + align:start position:0% +that sense except there's just a lot + + + align:start position:0% +that sense except there's just a lot +less interesting the game because + + align:start position:0% +less interesting the game because + + + align:start position:0% +less interesting the game because +there's a lot less strategy to it so you + + align:start position:0% +there's a lot less strategy to it so you + + + align:start position:0% +there's a lot less strategy to it so you +had a version of the game where all the + + align:start position:0% +had a version of the game where all the + + + align:start position:0% +had a version of the game where all the +squares were in play including the + + align:start position:0% +squares were in play including the + + + align:start position:0% +squares were in play including the +center tile and it just made it + + align:start position:0% +center tile and it just made it + + + align:start position:0% +center tile and it just made it +confusing for your players and you have + + align:start position:0% +confusing for your players and you have + + + align:start position:0% +confusing for your players and you have +a version of the game what is just like + + align:start position:0% +a version of the game what is just like + + + align:start position:0% +a version of the game what is just like +with this one possible solution to this + + align:start position:0% +with this one possible solution to this + + + align:start position:0% +with this one possible solution to this +problem is just take the center tile out + + align:start position:0% +problem is just take the center tile out + + + align:start position:0% +problem is just take the center tile out +yeah but that made it trivial oh yeah + + align:start position:0% +yeah but that made it trivial oh yeah + + + align:start position:0% +yeah but that made it trivial oh yeah +so we trying to find a middle ground and + + align:start position:0% +so we trying to find a middle ground and + + + align:start position:0% +so we trying to find a middle ground and +that's how we ended up with the idea + + align:start position:0% +that's how we ended up with the idea + + + align:start position:0% +that's how we ended up with the idea +where we had one single card in the + + align:start position:0% +where we had one single card in the + + + align:start position:0% +where we had one single card in the +middle because you can still use it we + + align:start position:0% +middle because you can still use it we + + + align:start position:0% +middle because you can still use it we +didn't have to worry about like the + + align:start position:0% +didn't have to worry about like the + + + align:start position:0% +didn't have to worry about like the +lines of play going through the middle + + align:start position:0% + + + + align:start position:0% + +okay so actually sounds like instead of + + align:start position:0% +okay so actually sounds like instead of + + + align:start position:0% +okay so actually sounds like instead of +a brittle idea you actually had a good + + align:start position:0% +a brittle idea you actually had a good + + + align:start position:0% +a brittle idea you actually had a good +robust idea which is that Center square + + align:start position:0% +robust idea which is that Center square + + + align:start position:0% +robust idea which is that Center square +is really problematic it's it has hope + + align:start position:0% +is really problematic it's it has hope + + + align:start position:0% +is really problematic it's it has hope +it has possibilities it has really + + align:start position:0% +it has possibilities it has really + + + align:start position:0% +it has possibilities it has really +interesting gameplay possibilities but + + align:start position:0% +interesting gameplay possibilities but + + + align:start position:0% +interesting gameplay possibilities but +for learning the game and stopping up + + align:start position:0% +for learning the game and stopping up + + + align:start position:0% +for learning the game and stopping up +the game it's problematic + + align:start position:0% +the game it's problematic + + + align:start position:0% +the game it's problematic +and so you'll found a way to say all + + align:start position:0% +and so you'll found a way to say all + + + align:start position:0% +and so you'll found a way to say all +right how do we deal with this center + + align:start position:0% +right how do we deal with this center + + + align:start position:0% +right how do we deal with this center +square instead of the solution of just + + align:start position:0% +square instead of the solution of just + + + align:start position:0% +square instead of the solution of just +delete the center square you know let's + + align:start position:0% +delete the center square you know let's + + + align:start position:0% +delete the center square you know let's +let's find a different way to work in + + align:start position:0% +let's find a different way to work in + + + align:start position:0% +let's find a different way to work in +into the game and and your and your + + align:start position:0% +into the game and and your and your + + + align:start position:0% +into the game and and your and your +final game as she does that something + + align:start position:0% +final game as she does that something + + + align:start position:0% +final game as she does that something +else that you can do is you know you if + + align:start position:0% +else that you can do is you know you if + + + align:start position:0% +else that you can do is you know you if +you've got an idea for your game it's + + align:start position:0% +you've got an idea for your game it's + + + align:start position:0% +you've got an idea for your game it's +kind of an wildy not quite sure what to + + align:start position:0% +kind of an wildy not quite sure what to + + + align:start position:0% +kind of an wildy not quite sure what to +do about it discuss it among your team + + align:start position:0% +do about it discuss it among your team + + + align:start position:0% +do about it discuss it among your team +but don't contact an experiment on it + + align:start position:0% +but don't contact an experiment on it + + + align:start position:0% +but don't contact an experiment on it +don't work in your rules don't try to + + align:start position:0% +don't work in your rules don't try to + + + align:start position:0% +don't work in your rules don't try to +implement it + + align:start position:0% +implement it + + + align:start position:0% +implement it +just get into everybody's heads because + + align:start position:0% +just get into everybody's heads because + + + align:start position:0% +just get into everybody's heads because +that idea may come bubbling up later and + + align:start position:0% +that idea may come bubbling up later and + + + align:start position:0% +that idea may come bubbling up later and +the bits of it might be applicable and + + align:start position:0% +the bits of it might be applicable and + + + align:start position:0% +the bits of it might be applicable and +slightly easier to implement way as you + + align:start position:0% +slightly easier to implement way as you + + + align:start position:0% +slightly easier to implement way as you +make progress in your game so none of us + + align:start position:0% +make progress in your game so none of us + + + align:start position:0% +make progress in your game so none of us +put it on a back burner but make sure + + align:start position:0% +put it on a back burner but make sure + + + align:start position:0% +put it on a back burner but make sure +you have actually had a chance to + + align:start position:0% +you have actually had a chance to + + + align:start position:0% +you have actually had a chance to +discuss it so that everyone's and all + + align:start position:0% +discuss it so that everyone's and all + + + align:start position:0% +discuss it so that everyone's and all +kind of thinking about it even if it's + + align:start position:0% +kind of thinking about it even if it's + + + align:start position:0% +kind of thinking about it even if it's +not something that you've decided that + + align:start position:0% +not something that you've decided that + + + align:start position:0% +not something that you've decided that +you why should we want to do right away + + align:start position:0% +you why should we want to do right away + + + align:start position:0% +you why should we want to do right away +might be a lot faster to just have a + + align:start position:0% +might be a lot faster to just have a + + + align:start position:0% +might be a lot faster to just have a +quick discussion to actually extend + + align:start position:0% +quick discussion to actually extend + + + align:start position:0% +quick discussion to actually extend +contact the experiment um yep so so + + align:start position:0% +contact the experiment um yep so so + + + align:start position:0% +contact the experiment um yep so so +those are a couple of strategies on it's + + align:start position:0% +those are a couple of strategies on it's + + + align:start position:0% +those are a couple of strategies on it's +like how do you sort of focus your + + align:start position:0% +like how do you sort of focus your + + + align:start position:0% +like how do you sort of focus your +experimenting time and this is probably + + align:start position:0% +experimenting time and this is probably + + + align:start position:0% +experimenting time and this is probably +not going to be very useful for Simon to + + align:start position:0% +not going to be very useful for Simon to + + + align:start position:0% +not going to be very useful for Simon to +but it is going to be useful for + + align:start position:0% +but it is going to be useful for + + + align:start position:0% +but it is going to be useful for +assignment three because it in Simon - + + align:start position:0% +assignment three because it in Simon - + + + align:start position:0% +assignment three because it in Simon - +yeah well pass hopefully you're well + + align:start position:0% +yeah well pass hopefully you're well + + + align:start position:0% +yeah well pass hopefully you're well +past the creating and adding new + + align:start position:0% +past the creating and adding new + + + align:start position:0% +past the creating and adding new +features the part and now you're just + + align:start position:0% +features the part and now you're just + + + align:start position:0% +features the part and now you're just +trying to get this out of the door for + + align:start position:0% +trying to get this out of the door for + + + align:start position:0% +trying to get this out of the door for +Wednesday so so let's talk about this + + align:start position:0% +Wednesday so so let's talk about this + + + align:start position:0% +Wednesday so so let's talk about this +this days now the well yeah in fact I'm + + align:start position:0% +this days now the well yeah in fact I'm + + + align:start position:0% +this days now the well yeah in fact I'm +gonna focus on this one isn't it sort of + + align:start position:0% +gonna focus on this one isn't it sort of + + + align:start position:0% +gonna focus on this one isn't it sort of +like cutting case where you're both + + align:start position:0% +like cutting case where you're both + + + align:start position:0% +like cutting case where you're both +cutting good stuff and bad stuff while + + align:start position:0% +cutting good stuff and bad stuff while + + + align:start position:0% +cutting good stuff and bad stuff while +you're cutting stuff in general because + + align:start position:0% +you're cutting stuff in general because + + + align:start position:0% +you're cutting stuff in general because +you have to be maybe because you're + + align:start position:0% +you have to be maybe because you're + + + align:start position:0% +you have to be maybe because you're +running out of time maybe because you + + align:start position:0% +running out of time maybe because you + + + align:start position:0% +running out of time maybe because you +are trying to get rid of the bad stuff + + align:start position:0% +are trying to get rid of the bad stuff + + + align:start position:0% +are trying to get rid of the bad stuff +so things that you need to do and this + + align:start position:0% +so things that you need to do and this + + + align:start position:0% +so things that you need to do and this +is something that I would like you to do + + align:start position:0% +is something that I would like you to do + + + align:start position:0% +is something that I would like you to do +today when you meet up in your teams is + + align:start position:0% +today when you meet up in your teams is + + + align:start position:0% +today when you meet up in your teams is +to determine what is the criteria which + + align:start position:0% +to determine what is the criteria which + + + align:start position:0% +to determine what is the criteria which +are going to cut a feature for instance + + align:start position:0% +are going to cut a feature for instance + + + align:start position:0% +are going to cut a feature for instance +come up with a quick description about + + align:start position:0% +come up with a quick description about + + + align:start position:0% +come up with a quick description about +what your games supposed to be all about + + align:start position:0% +what your games supposed to be all about + + + align:start position:0% +what your games supposed to be all about +you may already have written this in + + align:start position:0% +you may already have written this in + + + align:start position:0% +you may already have written this in +your rule so it might be in the very + + align:start position:0% +your rule so it might be in the very + + + align:start position:0% +your rule so it might be in the very +first paragraph all of your rules saying + + align:start position:0% +first paragraph all of your rules saying + + + align:start position:0% +first paragraph all of your rules saying +that our game is about getting entangled + + align:start position:0% +that our game is about getting entangled + + + align:start position:0% +that our game is about getting entangled +with other people you know yeah or all + + align:start position:0% +with other people you know yeah or all + + + align:start position:0% +with other people you know yeah or all +pushing them over for instance I I know + + align:start position:0% +pushing them over for instance I I know + + + align:start position:0% +pushing them over for instance I I know +that which is it you know and being I + + align:start position:0% +that which is it you know and being I + + + align:start position:0% +that which is it you know and being I +being able to identify and then when you + + align:start position:0% +being able to identify and then when you + + + align:start position:0% +being able to identify and then when you +look at all the rules in your game you + + align:start position:0% +look at all the rules in your game you + + + align:start position:0% +look at all the rules in your game you +can actually determine okay which chunks + + align:start position:0% +can actually determine okay which chunks + + + align:start position:0% +can actually determine okay which chunks +of our mechanics actually serve that + + align:start position:0% +of our mechanics actually serve that + + + align:start position:0% +of our mechanics actually serve that +goal + + align:start position:0% +goal + + + align:start position:0% +goal +everyone's don't you know there are + + align:start position:0% +everyone's don't you know there are + + + align:start position:0% +everyone's don't you know there are +things that this that just to keep your + + align:start position:0% +things that this that just to keep your + + + align:start position:0% +things that this that just to keep your +game going those may be fine to keep but + + align:start position:0% +game going those may be fine to keep but + + + align:start position:0% +game going those may be fine to keep but +are directly contributing to how good + + align:start position:0% +are directly contributing to how good + + + align:start position:0% +are directly contributing to how good +your game is those are just basically + + align:start position:0% +your game is those are just basically + + + align:start position:0% +your game is those are just basically +there to keep the thing working and + + align:start position:0% +there to keep the thing working and + + + align:start position:0% +there to keep the thing working and +maybe they can take a little bit about + + align:start position:0% +maybe they can take a little bit about + + + align:start position:0% +maybe they can take a little bit about +you that kind of suspect and then + + align:start position:0% +you that kind of suspect and then + + + align:start position:0% +you that kind of suspect and then +there's things that directly contribute + + align:start position:0% +there's things that directly contribute + + + align:start position:0% +there's things that directly contribute +to your whole gameplay that you're + + align:start position:0% +to your whole gameplay that you're + + + align:start position:0% +to your whole gameplay that you're +trying to achieve with your game and + + align:start position:0% +trying to achieve with your game and + + + align:start position:0% +trying to achieve with your game and +those are probably things that you want + + align:start position:0% +those are probably things that you want + + + align:start position:0% +those are probably things that you want +to spend a lot more time making sure + + align:start position:0% +to spend a lot more time making sure + + + align:start position:0% +to spend a lot more time making sure +that the rules are absolutely clear your + + align:start position:0% +that the rules are absolutely clear your + + + align:start position:0% +that the rules are absolutely clear your +players understand what they mean that + + align:start position:0% +players understand what they mean that + + + align:start position:0% +players understand what they mean that +you know if there's any other mechanics + + align:start position:0% +you know if there's any other mechanics + + + align:start position:0% +you know if there's any other mechanics +in your game they're supporting that you + + align:start position:0% +in your game they're supporting that you + + + align:start position:0% +in your game they're supporting that you +know that's that that you're the best + + align:start position:0% +know that's that that you're the best + + + align:start position:0% +know that's that that you're the best +meet your criteria for for what should + + align:start position:0% +meet your criteria for for what should + + + align:start position:0% +meet your criteria for for what should +stay in your game and then because once + + align:start position:0% +stay in your game and then because once + + + align:start position:0% +stay in your game and then because once +you know what your criteria is becomes a + + align:start position:0% +you know what your criteria is becomes a + + + align:start position:0% +you know what your criteria is becomes a +lot easier to be able to just look at + + align:start position:0% +lot easier to be able to just look at + + + align:start position:0% +lot easier to be able to just look at +everything that you've got deciding what + + align:start position:0% +everything that you've got deciding what + + + align:start position:0% +everything that you've got deciding what +to keep an invest more time in and what + + align:start position:0% +to keep an invest more time in and what + + + align:start position:0% +to keep an invest more time in and what +occurred there's couple of problems that + + align:start position:0% +occurred there's couple of problems that + + + align:start position:0% +occurred there's couple of problems that +people typically run into when it comes + + align:start position:0% +people typically run into when it comes + + + align:start position:0% +people typically run into when it comes +to cutting stuff out a couple of game + + align:start position:0% +to cutting stuff out a couple of game + + + align:start position:0% +to cutting stuff out a couple of game +developers refer to this as culling + + align:start position:0% +developers refer to this as culling + + + align:start position:0% +developers refer to this as culling +if you come from 3d graphics culling is + + align:start position:0% +if you come from 3d graphics culling is + + + align:start position:0% +if you come from 3d graphics culling is +a very common word is just to be able to + + align:start position:0% +a very common word is just to be able to + + + align:start position:0% +a very common word is just to be able to +just cut all the stuff out that you + + align:start position:0% +just cut all the stuff out that you + + + align:start position:0% +just cut all the stuff out that you +don't need um so for instance if you + + align:start position:0% +don't need um so for instance if you + + + align:start position:0% +don't need um so for instance if you +don't have an explicit culling criteria + + align:start position:0% +don't have an explicit culling criteria + + + align:start position:0% +don't have an explicit culling criteria +then you don't actually know you don't + + align:start position:0% +then you don't actually know you don't + + + align:start position:0% +then you don't actually know you don't +actually know why why a certain mechanic + + align:start position:0% +actually know why why a certain mechanic + + + align:start position:0% +actually know why why a certain mechanic +exists and you don't actually know + + align:start position:0% +exists and you don't actually know + + + align:start position:0% +exists and you don't actually know +whether you should keep it or not + + align:start position:0% +whether you should keep it or not + + + align:start position:0% +whether you should keep it or not +so that discussion should be something + + align:start position:0% +so that discussion should be something + + + align:start position:0% +so that discussion should be something +that you happen today you know + + align:start position:0% +that you happen today you know + + + align:start position:0% +that you happen today you know +everything in the end what is your game + + align:start position:0% +everything in the end what is your game + + + align:start position:0% +everything in the end what is your game +about and that's your game might really + + align:start position:0% +about and that's your game might really + + + align:start position:0% +about and that's your game might really +need that the other cut you can't have + + align:start position:0% +need that the other cut you can't have + + + align:start position:0% +need that the other cut you can't have +other coloring criteria that aren't that + + align:start position:0% +other coloring criteria that aren't that + + + align:start position:0% +other coloring criteria that aren't that +there are that this game run in five + + align:start position:0% +there are that this game run in five + + + align:start position:0% +there are that this game run in five +minutes I was a limit for this one ten + + align:start position:0% +minutes I was a limit for this one ten + + + align:start position:0% +minutes I was a limit for this one ten +minutes I believe was twenty minutes + + align:start position:0% +minutes I believe was twenty minutes + + + align:start position:0% +minutes I believe was twenty minutes +okay so the game doesn't run you know if + + align:start position:0% +okay so the game doesn't run you know if + + + align:start position:0% +okay so the game doesn't run you know if +the game needs to run in twenty minutes + + align:start position:0% +the game needs to run in twenty minutes + + + align:start position:0% +the game needs to run in twenty minutes +because we as instructors gave you that + + align:start position:0% +because we as instructors gave you that + + + align:start position:0% +because we as instructors gave you that +limitation then that's probably a + + align:start position:0% +limitation then that's probably a + + + align:start position:0% +limitation then that's probably a +perfectly reasonable calling criteria + + align:start position:0% +perfectly reasonable calling criteria + + + align:start position:0% +perfectly reasonable calling criteria +for you to use what in our game is sort + + align:start position:0% +for you to use what in our game is sort + + + align:start position:0% +for you to use what in our game is sort +of contributing to towards this and + + align:start position:0% +of contributing to towards this and + + + align:start position:0% +of contributing to towards this and +what's actually getting in our way of + + align:start position:0% +what's actually getting in our way of + + + align:start position:0% +what's actually getting in our way of +hitting that target + + align:start position:0% + + + + align:start position:0% + +let's see something else that comes in + + align:start position:0% +let's see something else that comes in + + + align:start position:0% +let's see something else that comes in +that affects culling that affects this + + align:start position:0% +that affects culling that affects this + + + align:start position:0% +that affects culling that affects this +phase is when you conduct experiments + + align:start position:0% +phase is when you conduct experiments + + + align:start position:0% +phase is when you conduct experiments +here but your experiments are not very + + align:start position:0% +here but your experiments are not very + + + align:start position:0% +here but your experiments are not very +tangible the kind of floaty and wavy + + align:start position:0% +tangible the kind of floaty and wavy + + + align:start position:0% +tangible the kind of floaty and wavy +this usually happens in teams that like + + align:start position:0% +this usually happens in teams that like + + + align:start position:0% +this usually happens in teams that like +to talk out all of their ideas but I + + align:start position:0% +to talk out all of their ideas but I + + + align:start position:0% +to talk out all of their ideas but I +don't actually like to do a lot of like + + align:start position:0% +don't actually like to do a lot of like + + + align:start position:0% +don't actually like to do a lot of like +hardcore prototyping and play testing I + + align:start position:0% +hardcore prototyping and play testing I + + + align:start position:0% +hardcore prototyping and play testing I +hope that's not so much of a problem for + + align:start position:0% +hope that's not so much of a problem for + + + align:start position:0% +hope that's not so much of a problem for +anyone in this class by now you've got + + align:start position:0% +anyone in this class by now you've got + + + align:start position:0% +anyone in this class by now you've got +in a lot of practice in that but you may + + align:start position:0% +in a lot of practice in that but you may + + + align:start position:0% +in a lot of practice in that but you may +have a couple of rules our mechanics + + align:start position:0% +have a couple of rules our mechanics + + + align:start position:0% +have a couple of rules our mechanics +that have ended up in your game that you + + align:start position:0% +that have ended up in your game that you + + + align:start position:0% +that have ended up in your game that you +never actually prototype that you've + + align:start position:0% +never actually prototype that you've + + + align:start position:0% +never actually prototype that you've +never actually tested out where real + + align:start position:0% +never actually tested out where real + + + align:start position:0% +never actually tested out where real +people make sure that whatever actually + + align:start position:0% +people make sure that whatever actually + + + align:start position:0% +people make sure that whatever actually +ends up in the version that you hand + + align:start position:0% +ends up in the version that you hand + + + align:start position:0% +ends up in the version that you hand +them on Wednesday is something that + + align:start position:0% +them on Wednesday is something that + + + align:start position:0% +them on Wednesday is something that +you've actually tested it's something + + align:start position:0% +you've actually tested it's something + + + align:start position:0% +you've actually tested it's something +that you've actually gotten some real + + align:start position:0% +that you've actually gotten some real + + + align:start position:0% +that you've actually gotten some real +data about whether is working or not + + align:start position:0% + + + + align:start position:0% + +this one this one happens with every + + align:start position:0% +this one this one happens with every + + + align:start position:0% +this one this one happens with every +student project but the students general + + align:start position:0% +student project but the students general + + + align:start position:0% +student project but the students general +game developers in general always + + align:start position:0% +game developers in general always + + + align:start position:0% +game developers in general always +assumed that adding more stuff is better + + align:start position:0% +assumed that adding more stuff is better + + + align:start position:0% +assumed that adding more stuff is better +takes a very very very seasoned game + + align:start position:0% +takes a very very very seasoned game + + + align:start position:0% +takes a very very very seasoned game +designer to sort of realize that + + align:start position:0% +designer to sort of realize that + + + align:start position:0% +designer to sort of realize that +sometimes simplicity is good and again I + + align:start position:0% +sometimes simplicity is good and again I + + + align:start position:0% +sometimes simplicity is good and again I +hope this is not the terribly new + + align:start position:0% +hope this is not the terribly new + + + align:start position:0% +hope this is not the terribly new +revelation to the people in this class + + align:start position:0% +revelation to the people in this class + + + align:start position:0% +revelation to the people in this class +but I see in the student projects all + + align:start position:0% +but I see in the student projects all + + + align:start position:0% +but I see in the student projects all +time I see in certain projects where + + align:start position:0% +time I see in certain projects where + + + align:start position:0% +time I see in certain projects where +they assume that more features and more + + align:start position:0% +they assume that more features and more + + + align:start position:0% +they assume that more features and more +complexity is going to be better in fact + + align:start position:0% +complexity is going to be better in fact + + + align:start position:0% +complexity is going to be better in fact +I saw some of them in assignment one and + + align:start position:0% +I saw some of them in assignment one and + + + align:start position:0% +I saw some of them in assignment one and +we're going to be talking a little bit + + align:start position:0% +we're going to be talking a little bit + + + align:start position:0% +we're going to be talking a little bit +about that more complexity doesn't + + align:start position:0% +about that more complexity doesn't + + + align:start position:0% +about that more complexity doesn't +necessarily always make for a better + + align:start position:0% +necessarily always make for a better + + + align:start position:0% +necessarily always make for a better +game maybe making a more interesting + + align:start position:0% +game maybe making a more interesting + + + align:start position:0% +game maybe making a more interesting +intellectual problem there's not + + align:start position:0% +intellectual problem there's not + + + align:start position:0% +intellectual problem there's not +necessarily always making into a more + + align:start position:0% +necessarily always making into a more + + + align:start position:0% +necessarily always making into a more +entertaining game let's see one thing + + align:start position:0% +entertaining game let's see one thing + + + align:start position:0% +entertaining game let's see one thing +about culling is that cutting features + + align:start position:0% +about culling is that cutting features + + + align:start position:0% +about culling is that cutting features +and cutting stuff out kind of takes + + align:start position:0% +and cutting stuff out kind of takes + + + align:start position:0% +and cutting stuff out kind of takes +practice you've got to do it fairly + + align:start position:0% +practice you've got to do it fairly + + + align:start position:0% +practice you've got to do it fairly +regularly for the a for assignment three + + align:start position:0% +regularly for the a for assignment three + + + align:start position:0% +regularly for the a for assignment three +which is going to be starting on + + align:start position:0% +which is going to be starting on + + + align:start position:0% +which is going to be starting on +Wednesday we actually started on + + align:start position:0% +Wednesday we actually started on + + + align:start position:0% +Wednesday we actually started on +Wednesday what I'm going to ask you to + + align:start position:0% +Wednesday what I'm going to ask you to + + + align:start position:0% +Wednesday what I'm going to ask you to +do is try cutting a feature every week + + align:start position:0% +do is try cutting a feature every week + + + align:start position:0% +do is try cutting a feature every week +you know like just say all right what's + + align:start position:0% +you know like just say all right what's + + + align:start position:0% +you know like just say all right what's +on a chopping block this week you know + + align:start position:0% +on a chopping block this week you know + + + align:start position:0% +on a chopping block this week you know +every every Monday oh you know + + align:start position:0% +every every Monday oh you know + + + align:start position:0% +every every Monday oh you know +Wednesday or if you have regular meeting + + align:start position:0% +Wednesday or if you have regular meeting + + + align:start position:0% +Wednesday or if you have regular meeting +time on Saturday or something like that + + align:start position:0% +time on Saturday or something like that + + + align:start position:0% +time on Saturday or something like that +just like what's on the chopping about + + align:start position:0% +just like what's on the chopping about + + + align:start position:0% +just like what's on the chopping about +what what is the least useful thing that + + align:start position:0% +what what is the least useful thing that + + + align:start position:0% +what what is the least useful thing that +we've got in our game right now and just + + align:start position:0% +we've got in our game right now and just + + + align:start position:0% +we've got in our game right now and just +try that because you can always add + + align:start position:0% +try that because you can always add + + + align:start position:0% +try that because you can always add +stuff in later you can always remember + + align:start position:0% +stuff in later you can always remember + + + align:start position:0% +stuff in later you can always remember +that this is a cyclical this is a + + align:start position:0% +that this is a cyclical this is a + + + align:start position:0% +that this is a cyclical this is a +cyclical thing they're going to be + + align:start position:0% +cyclical thing they're going to be + + + align:start position:0% +cyclical thing they're going to be +adding they're cutting adding and + + align:start position:0% +adding they're cutting adding and + + + align:start position:0% +adding they're cutting adding and +cutting adding a lot of practice or the + + align:start position:0% +cutting adding a lot of practice or the + + + align:start position:0% +cutting adding a lot of practice or the +adding part but how but but you've got + + align:start position:0% +adding part but how but but you've got + + + align:start position:0% +adding part but how but but you've got +to practice a little bit more on the + + align:start position:0% +to practice a little bit more on the + + + align:start position:0% +to practice a little bit more on the +cutting part now and you've got time to + + align:start position:0% +cutting part now and you've got time to + + + align:start position:0% +cutting part now and you've got time to +be able to do this for assignment read a + + align:start position:0% +be able to do this for assignment read a + + + align:start position:0% +be able to do this for assignment read a +little bit more time on assignment + + align:start position:0% +little bit more time on assignment + + + align:start position:0% +little bit more time on assignment +through that that you had on assignment + + align:start position:0% +through that that you had on assignment + + + align:start position:0% +through that that you had on assignment +- so start setting yourself like a + + align:start position:0% +- so start setting yourself like a + + + align:start position:0% +- so start setting yourself like a +schedule + + align:start position:0% +schedule + + + align:start position:0% +schedule +all right maybe definitely going to cut + + align:start position:0% +all right maybe definitely going to cut + + + align:start position:0% +all right maybe definitely going to cut +something I don't know what it is but + + align:start position:0% +something I don't know what it is but + + + align:start position:0% +something I don't know what it is but +we're going to meet up as a team and + + align:start position:0% +we're going to meet up as a team and + + + align:start position:0% +we're going to meet up as a team and +we're going to decide that and if it + + align:start position:0% +we're going to decide that and if it + + + align:start position:0% +we're going to decide that and if it +turns out that was the wrong thing to + + align:start position:0% +turns out that was the wrong thing to + + + align:start position:0% +turns out that was the wrong thing to +cut you can add it back later but that + + align:start position:0% +cut you can add it back later but that + + + align:start position:0% +cut you can add it back later but that +allows you to focus your efforts on the + + align:start position:0% +allows you to focus your efforts on the + + + align:start position:0% +allows you to focus your efforts on the +things that you've said that you deem is + + align:start position:0% +things that you've said that you deem is + + + align:start position:0% +things that you've said that you deem is +more important for a short amount of + + align:start position:0% +more important for a short amount of + + + align:start position:0% +more important for a short amount of +time it can be hard to be objective + + align:start position:0% +time it can be hard to be objective + + + align:start position:0% +time it can be hard to be objective +about this process something that we've + + align:start position:0% +about this process something that we've + + + align:start position:0% +about this process something that we've +done in mostly our video game + + align:start position:0% +done in mostly our video game + + + align:start position:0% +done in mostly our video game +development but you can do this in paper + + align:start position:0% +development but you can do this in paper + + + align:start position:0% +development but you can do this in paper +prototypes so have it so had people very + + align:start position:0% +prototypes so have it so had people very + + + align:start position:0% +prototypes so have it so had people very +very simple survey forms that basically + + align:start position:0% +very simple survey forms that basically + + + align:start position:0% +very simple survey forms that basically +say how fun did you find this how fun + + align:start position:0% +say how fun did you find this how fun + + + align:start position:0% +say how fun did you find this how fun +did you find that you know say your game + + align:start position:0% +did you find that you know say your game + + + align:start position:0% +did you find that you know say your game +has different roles you know you have a + + align:start position:0% +has different roles you know you have a + + + align:start position:0% +has different roles you know you have a +tinker tailor soldier spy these are your + + align:start position:0% +tinker tailor soldier spy these are your + + + align:start position:0% +tinker tailor soldier spy these are your +four roles in your game you know and you + + align:start position:0% +four roles in your game you know and you + + + align:start position:0% +four roles in your game you know and you +just hand out the survey form the how + + align:start position:0% +just hand out the survey form the how + + + align:start position:0% +just hand out the survey form the how +fun did you find being a tinker how + + align:start position:0% +fun did you find being a tinker how + + + align:start position:0% +fun did you find being a tinker how +often do you find being a tailor it is + + align:start position:0% +often do you find being a tailor it is + + + align:start position:0% +often do you find being a tailor it is +one to five you know and that that isn't + + align:start position:0% +one to five you know and that that isn't + + + align:start position:0% +one to five you know and that that isn't +terribly much information but it gives + + align:start position:0% +terribly much information but it gives + + + align:start position:0% +terribly much information but it gives +you just enough information to to help + + align:start position:0% +you just enough information to to help + + + align:start position:0% +you just enough information to to help +you concentrate your efforts on what's + + align:start position:0% +you concentrate your efforts on what's + + + align:start position:0% +you concentrate your efforts on what's +the most problematic thing in our game + + align:start position:0% +the most problematic thing in our game + + + align:start position:0% +the most problematic thing in our game +right now + + align:start position:0% +right now + + + align:start position:0% +right now +you know you can't go into greater + + align:start position:0% +you know you can't go into greater + + + align:start position:0% +you know you can't go into greater +detail later you think that the game was + + align:start position:0% +detail later you think that the game was + + + align:start position:0% +detail later you think that the game was +too long too short you you know you too + + align:start position:0% +too long too short you you know you too + + + align:start position:0% +too long too short you you know you too +too challenging + + align:start position:0% +too challenging + + + align:start position:0% +too challenging +too easy to lock based you know require + + align:start position:0% +too easy to lock based you know require + + + align:start position:0% +too easy to lock based you know require +too much thought you can put these + + align:start position:0% +too much thought you can put these + + + align:start position:0% +too much thought you can put these +things on these like five-point scales + + align:start position:0% +things on these like five-point scales + + + align:start position:0% +things on these like five-point scales +and to be able to give you a little bit + + align:start position:0% +and to be able to give you a little bit + + + align:start position:0% +and to be able to give you a little bit +of feedback doesn't necessarily tell you + + align:start position:0% +of feedback doesn't necessarily tell you + + + align:start position:0% +of feedback doesn't necessarily tell you +what the problem is + + align:start position:0% +what the problem is + + + align:start position:0% +what the problem is +but it tells you where the problem might + + align:start position:0% +but it tells you where the problem might + + + align:start position:0% +but it tells you where the problem might +lie and that will help focus your + + align:start position:0% +lie and that will help focus your + + + align:start position:0% +lie and that will help focus your +discussion than your efforts a little + + align:start position:0% +discussion than your efforts a little + + + align:start position:0% +discussion than your efforts a little +bit + + align:start position:0% + + + + align:start position:0% + +yeah and finally the most important + + align:start position:0% +yeah and finally the most important + + + align:start position:0% +yeah and finally the most important +thing is that you've got to keep doing + + align:start position:0% +thing is that you've got to keep doing + + + align:start position:0% +thing is that you've got to keep doing +this over and over and over again if you + + align:start position:0% +this over and over and over again if you + + + align:start position:0% +this over and over and over again if you +just do this once you you you kind of + + align:start position:0% +just do this once you you you kind of + + + align:start position:0% +just do this once you you you kind of +end up in this situation where you've + + align:start position:0% +end up in this situation where you've + + + align:start position:0% +end up in this situation where you've +got a bunch of good ideas but the bad + + align:start position:0% +got a bunch of good ideas but the bad + + + align:start position:0% +got a bunch of good ideas but the bad +ideas are still there what you + + align:start position:0% +ideas are still there what you + + + align:start position:0% +ideas are still there what you +eventually want to get to I'm gonna + + align:start position:0% +eventually want to get to I'm gonna + + + align:start position:0% +eventually want to get to I'm gonna +extend this greater this what you + + align:start position:0% +extend this greater this what you + + + align:start position:0% +extend this greater this what you +eventually want to get to is a situation + + align:start position:0% +eventually want to get to is a situation + + + align:start position:0% +eventually want to get to is a situation +where the only stuff that's left in your + + align:start position:0% +where the only stuff that's left in your + + + align:start position:0% +where the only stuff that's left in your +game is the stuff that you that is worth + + align:start position:0% +game is the stuff that you that is worth + + + align:start position:0% +game is the stuff that you that is worth +keeping and that works well and all the + + align:start position:0% +keeping and that works well and all the + + + align:start position:0% +keeping and that works well and all the +stuff that's that and all the stuff that + + align:start position:0% +stuff that's that and all the stuff that + + + align:start position:0% +stuff that's that and all the stuff that +was bad you find a completely cut it out + + align:start position:0% +was bad you find a completely cut it out + + + align:start position:0% +was bad you find a completely cut it out +you know all you've improved it to the + + align:start position:0% +you know all you've improved it to the + + + align:start position:0% +you know all you've improved it to the +point where it is actually a desirable + + align:start position:0% +point where it is actually a desirable + + + align:start position:0% +point where it is actually a desirable +feature and you're only going to be able + + align:start position:0% +feature and you're only going to be able + + + align:start position:0% +feature and you're only going to be able +to get through at through multiple + + align:start position:0% +to get through at through multiple + + + align:start position:0% +to get through at through multiple +iterations are not going to get through + + align:start position:0% +iterations are not going to get through + + + align:start position:0% +iterations are not going to get through +that just by introducing something at + + align:start position:0% +that just by introducing something at + + + align:start position:0% +that just by introducing something at +the last minute and hoping that it works + + align:start position:0% +the last minute and hoping that it works + + + align:start position:0% +the last minute and hoping that it works +because you haven't had time to actually + + align:start position:0% +because you haven't had time to actually + + + align:start position:0% +because you haven't had time to actually +improve it and polish it yet + + align:start position:0% + + + + align:start position:0% + +now some something that's less of a + + align:start position:0% +now some something that's less of a + + + align:start position:0% +now some something that's less of a +problem for this class but maybe a + + align:start position:0% +problem for this class but maybe a + + + align:start position:0% +problem for this class but maybe a +problem in your other game design + + align:start position:0% +problem in your other game design + + + align:start position:0% +problem in your other game design +experiments outside of class is that you + + align:start position:0% +experiments outside of class is that you + + + align:start position:0% +experiments outside of class is that you +may not know when to where to call it a + + align:start position:0% +may not know when to where to call it a + + + align:start position:0% +may not know when to where to call it a +day right like you can repeat this + + align:start position:0% +day right like you can repeat this + + + align:start position:0% +day right like you can repeat this +process forever + + align:start position:0% +process forever + + + align:start position:0% +process forever +and you've heard about games that have + + align:start position:0% +and you've heard about games that have + + + align:start position:0% +and you've heard about games that have +been going on for four or five years how + + align:start position:0% +been going on for four or five years how + + + align:start position:0% +been going on for four or five years how +long you can forever in production for + + align:start position:0% +long you can forever in production for + + + align:start position:0% +long you can forever in production for +fifteen at least ten and that was + + align:start position:0% +fifteen at least ten and that was + + + align:start position:0% +fifteen at least ten and that was +actually a pro one one example of where + + align:start position:0% +actually a pro one one example of where + + + align:start position:0% +actually a pro one one example of where +new technology just ended up changing + + align:start position:0% +new technology just ended up changing + + + align:start position:0% +new technology just ended up changing +the teaching the foundation of which + + align:start position:0% +the teaching the foundation of which + + + align:start position:0% +the teaching the foundation of which +that game was built on over and over and + + align:start position:0% +that game was built on over and over and + + + align:start position:0% +that game was built on over and over and +over again they just kept resetting the + + align:start position:0% +over again they just kept resetting the + + + align:start position:0% +over again they just kept resetting the +game engine development and just up + + align:start position:0% +game engine development and just up + + + align:start position:0% +game engine development and just up +forever one of the one thing that that + + align:start position:0% +forever one of the one thing that that + + + align:start position:0% +forever one of the one thing that that +that game could probably have used is + + align:start position:0% +that game could probably have used is + + + align:start position:0% +that game could probably have used is +just some sort of like standard criteria + + align:start position:0% +just some sort of like standard criteria + + + align:start position:0% +just some sort of like standard criteria +of saying like once we hit this criteria + + align:start position:0% +of saying like once we hit this criteria + + + align:start position:0% +of saying like once we hit this criteria +we're shipping this game right it could + + align:start position:0% +we're shipping this game right it could + + + align:start position:0% +we're shipping this game right it could +be once we spent X amount of money that + + align:start position:0% +be once we spent X amount of money that + + + align:start position:0% +be once we spent X amount of money that +probably should have made a case for + + align:start position:0% +probably should have made a case for + + + align:start position:0% +probably should have made a case for +that particular game but but it could + + align:start position:0% +that particular game but but it could + + + align:start position:0% +that particular game but but it could +have been once + + align:start position:0% +have been once + + + align:start position:0% +have been once +our informal internal surveys hit a + + align:start position:0% +our informal internal surveys hit a + + + align:start position:0% +our informal internal surveys hit a +rating of 4 out of 5 right you know that + + align:start position:0% +rating of 4 out of 5 right you know that + + + align:start position:0% +rating of 4 out of 5 right you know that +might have been good enough some + + align:start position:0% +might have been good enough some + + + align:start position:0% +might have been good enough some +companies don't settle for that there + + align:start position:0% +companies don't settle for that there + + + align:start position:0% +companies don't settle for that there +are a couple + + align:start position:0% +are a couple + + + align:start position:0% +are a couple +like we're only going to release the + + align:start position:0% +like we're only going to release the + + + align:start position:0% +like we're only going to release the +absolute best game that we absolutely + + align:start position:0% +absolute best game that we absolutely + + + align:start position:0% +absolute best game that we absolutely +can but don't get yourself internally + + align:start position:0% +can but don't get yourself internally + + + align:start position:0% +can but don't get yourself internally +they do have criteria and when these + + align:start position:0% +they do have criteria and when these + + + align:start position:0% +they do have criteria and when these +games have Bishop even in ten daughters + + align:start position:0% +games have Bishop even in ten daughters + + + align:start position:0% +games have Bishop even in ten daughters +and in ten dozen notorious from shipping + + align:start position:0% +and in ten dozen notorious from shipping + + + align:start position:0% +and in ten dozen notorious from shipping +make games because they have this mantra + + align:start position:0% +make games because they have this mantra + + + align:start position:0% +make games because they have this mantra +that a game is late for a short while + + align:start position:0% +that a game is late for a short while + + + align:start position:0% +that a game is late for a short while +and a bad game is bad forever so so + + align:start position:0% +and a bad game is bad forever so so + + + align:start position:0% +and a bad game is bad forever so so +that's that's that's why they say to the + + align:start position:0% +that's that's that's why they say to the + + + align:start position:0% +that's that's that's why they say to the +public internally they ship by Christmas + + align:start position:0% +public internally they ship by Christmas + + + align:start position:0% +public internally they ship by Christmas +they get those games help to the market + + align:start position:0% +they get those games help to the market + + + align:start position:0% +they get those games help to the market +because they have a time box that's the + + align:start position:0% +because they have a time box that's the + + + align:start position:0% +because they have a time box that's the +other way to do it and it says like well + + align:start position:0% +other way to do it and it says like well + + + align:start position:0% +other way to do it and it says like well +we have to be able to get into the + + align:start position:0% +we have to be able to get into the + + + align:start position:0% +we have to be able to get into the +manufacturing process to print those + + align:start position:0% +manufacturing process to print those + + + align:start position:0% +manufacturing process to print those +discs less of an issue nowadays but + + align:start position:0% +discs less of an issue nowadays but + + + align:start position:0% +discs less of an issue nowadays but +Nintendo still operates in in this + + align:start position:0% +Nintendo still operates in in this + + + align:start position:0% +Nintendo still operates in in this +fashion because they grew up as + + align:start position:0% +fashion because they grew up as + + + align:start position:0% +fashion because they grew up as +cartridge manufacturers so they actually + + align:start position:0% +cartridge manufacturers so they actually + + + align:start position:0% +cartridge manufacturers so they actually +had to print it now when it comes to + + align:start position:0% +had to print it now when it comes to + + + align:start position:0% +had to print it now when it comes to +publishing paper King no that's that + + align:start position:0% +publishing paper King no that's that + + + align:start position:0% +publishing paper King no that's that +timeline can be even longer right + + align:start position:0% +timeline can be even longer right + + + align:start position:0% +timeline can be even longer right +because you have to put stuff on you + + align:start position:0% +because you have to put stuff on you + + + align:start position:0% +because you have to put stuff on you +have to put ink on paper you have to + + align:start position:0% +have to put ink on paper you have to + + + align:start position:0% +have to put ink on paper you have to +have it folded you have to get all the + + align:start position:0% +have it folded you have to get all the + + + align:start position:0% +have it folded you have to get all the +plastic and stuff put in plastic bags + + align:start position:0% +plastic and stuff put in plastic bags + + + align:start position:0% +plastic and stuff put in plastic bags +and then put into the box and then put + + align:start position:0% +and then put into the box and then put + + + align:start position:0% +and then put into the box and then put +into pallets and then shipped from China + + align:start position:0% +into pallets and then shipped from China + + + align:start position:0% +into pallets and then shipped from China +usually over to stars all over the + + align:start position:0% +usually over to stars all over the + + + align:start position:0% +usually over to stars all over the +United States so that they're in stores + + align:start position:0% +United States so that they're in stores + + + align:start position:0% +United States so that they're in stores +in time for Christmas and that's like a + + align:start position:0% +in time for Christmas and that's like a + + + align:start position:0% +in time for Christmas and that's like a +huge time like so that's so that became + + align:start position:0% +huge time like so that's so that became + + + align:start position:0% +huge time like so that's so that became +the time limit you sometimes you just + + align:start position:0% +the time limit you sometimes you just + + + align:start position:0% +the time limit you sometimes you just +set a time limit because you have to be + + align:start position:0% +set a time limit because you have to be + + + align:start position:0% +set a time limit because you have to be +able to meet ship dates um it's not that + + align:start position:0% +able to meet ship dates um it's not that + + + align:start position:0% +able to meet ship dates um it's not that +very complicated now you're working your + + align:start position:0% +very complicated now you're working your + + + align:start position:0% +very complicated now you're working your +own internal Kickstarter project or + + align:start position:0% +own internal Kickstarter project or + + + align:start position:0% +own internal Kickstarter project or +something with where you are well you + + align:start position:0% +something with where you are well you + + + align:start position:0% +something with where you are well you +already know who's going to buy your + + align:start position:0% +already know who's going to buy your + + + align:start position:0% +already know who's going to buy your +game because they pay for it upfront + + align:start position:0% +game because they pay for it upfront + + + align:start position:0% +game because they pay for it upfront +before you even started manufacturing um + + align:start position:0% +before you even started manufacturing um + + + align:start position:0% +before you even started manufacturing um +I think we'll hear about more about that + + align:start position:0% +I think we'll hear about more about that + + + align:start position:0% +I think we'll hear about more about that +maybe in about two weeks + + align:start position:0% +maybe in about two weeks + + + align:start position:0% +maybe in about two weeks +about one week April 9th yeah we'll have + + align:start position:0% +about one week April 9th yeah we'll have + + + align:start position:0% +about one week April 9th yeah we'll have +a couple of folks who actually work in + + align:start position:0% +a couple of folks who actually work in + + + align:start position:0% +a couple of folks who actually work in +the the board game publishing industry + + align:start position:0% +the the board game publishing industry + + + align:start position:0% +the the board game publishing industry +to talk a little bit about how they set + + align:start position:0% +to talk a little bit about how they set + + + align:start position:0% +to talk a little bit about how they set +goal goal posts and time and deadlines + + align:start position:0% +goal goal posts and time and deadlines + + + align:start position:0% +goal goal posts and time and deadlines +for themselves one of the considerations + + align:start position:0% +for themselves one of the considerations + + + align:start position:0% +for themselves one of the considerations +or that but in the end is just they had + + align:start position:0% +or that but in the end is just they had + + + align:start position:0% +or that but in the end is just they had +to set a goal somehow either is a + + align:start position:0% +to set a goal somehow either is a + + + align:start position:0% +to set a goal somehow either is a +quality goal or is a time goal and once + + align:start position:0% +quality goal or is a time goal and once + + + align:start position:0% +quality goal or is a time goal and once +you hit that you have to ship because + + align:start position:0% +you hit that you have to ship because + + + align:start position:0% +you hit that you have to ship because +you can always do + + align:start position:0% +you can always do + + + align:start position:0% +you can always do +if you saw the quality goal you can + + align:start position:0% +if you saw the quality goal you can + + + align:start position:0% +if you saw the quality goal you can +always do better than that the more time + + align:start position:0% +always do better than that the more time + + + align:start position:0% +always do better than that the more time +that you spend the more you know the + + align:start position:0% +that you spend the more you know the + + + align:start position:0% +that you spend the more you know the +higher goal but theoretically you are + + align:start position:0% +higher goal but theoretically you are + + + align:start position:0% +higher goal but theoretically you are +sticking to this the higher quality your + + align:start position:0% +sticking to this the higher quality your + + + align:start position:0% +sticking to this the higher quality your +game is going to get but any don't ship + + align:start position:0% +game is going to get but any don't ship + + + align:start position:0% +game is going to get but any don't ship +you just have to manage angry returns so + + align:start position:0% +you just have to manage angry returns so + + + align:start position:0% +you just have to manage angry returns so +never be able to move on to your next + + align:start position:0% +never be able to move on to your next + + + align:start position:0% +never be able to move on to your next +project and I'm going to get revenue + + align:start position:0% +project and I'm going to get revenue + + + align:start position:0% +project and I'm going to get revenue +from the from from the project that you + + align:start position:0% +from the from from the project that you + + + align:start position:0% +from the from from the project that you +started and your game may not be + + align:start position:0% +started and your game may not be + + + align:start position:0% +started and your game may not be +improved by that much more just by + + align:start position:0% +improved by that much more just by + + + align:start position:0% +improved by that much more just by +spending extra time on it um okay so + + align:start position:0% +spending extra time on it um okay so + + + align:start position:0% +spending extra time on it um okay so +again we're going to talk a little bit + + align:start position:0% +again we're going to talk a little bit + + + align:start position:0% +again we're going to talk a little bit +about things that are relevant to to + + align:start position:0% +about things that are relevant to to + + + align:start position:0% +about things that are relevant to to +start from what we've observed from + + align:start position:0% +start from what we've observed from + + + align:start position:0% +start from what we've observed from +assignment 1 and then for us for for + + align:start position:0% +assignment 1 and then for us for for + + + align:start position:0% +assignment 1 and then for us for for +your team time to today start talking + + align:start position:0% +your team time to today start talking + + + align:start position:0% +your team time to today start talking +about what is your calling criteria what + + align:start position:0% +about what is your calling criteria what + + + align:start position:0% +about what is your calling criteria what +are you trying to achieve with what + + align:start position:0% +are you trying to achieve with what + + + align:start position:0% +are you trying to achieve with what +what's the simplest thing that you're + + align:start position:0% +what's the simplest thing that you're + + + align:start position:0% +what's the simplest thing that you're +trying to achieve with this game + + align:start position:0% +trying to achieve with this game + + + align:start position:0% +trying to achieve with this game +simplest and the simplest way to + + align:start position:0% +simplest and the simplest way to + + + align:start position:0% +simplest and the simplest way to +describe it and then look at all the + + align:start position:0% +describe it and then look at all the + + + align:start position:0% +describe it and then look at all the +things in your game based on that + + align:start position:0% +things in your game based on that + + + align:start position:0% +things in your game based on that +criteria and whatever doesn't meet that + + align:start position:0% +criteria and whatever doesn't meet that + + + align:start position:0% +criteria and whatever doesn't meet that +might be something that you want to cut + + align:start position:0% +might be something that you want to cut + + + align:start position:0% +might be something that you want to cut +out especially if it's already causing + + align:start position:0% +out especially if it's already causing + + + align:start position:0% +out especially if it's already causing +you problems you know and maybe you're + + align:start position:0% +you problems you know and maybe you're + + + align:start position:0% +you problems you know and maybe you're +just say cute I'm free up a little bit + + align:start position:0% +just say cute I'm free up a little bit + + + align:start position:0% +just say cute I'm free up a little bit +more time to work on the stuff that's + + align:start position:0% +more time to work on the stuff that's + + + align:start position:0% +more time to work on the stuff that's +already working you can polish up a + + align:start position:0% +already working you can polish up a + + + align:start position:0% +already working you can polish up a +little bit more so any questions about + + align:start position:0% +little bit more so any questions about + + + align:start position:0% +little bit more so any questions about +adding and cutting teachers + + align:start position:0% + + + + align:start position:0% + +okay so related taking all this relating + + align:start position:0% +okay so related taking all this relating + + + align:start position:0% +okay so related taking all this relating +it to this kind of wine and then going + + align:start position:0% +it to this kind of wine and then going + + + align:start position:0% +it to this kind of wine and then going +into assignment two and also starting to + + align:start position:0% +into assignment two and also starting to + + + align:start position:0% +into assignment two and also starting to +cut inside of one so when it comes to + + align:start position:0% +cut inside of one so when it comes to + + + align:start position:0% +cut inside of one so when it comes to +advanced rules and basic rules if you're + + align:start position:0% +advanced rules and basic rules if you're + + + align:start position:0% +advanced rules and basic rules if you're +gonna have if you're going to do an + + align:start position:0% +gonna have if you're going to do an + + + align:start position:0% +gonna have if you're going to do an +advanced rule set and a basic rule set + + align:start position:0% +advanced rule set and a basic rule set + + + align:start position:0% +advanced rule set and a basic rule set +make sure your basic rule set matches + + align:start position:0% +make sure your basic rule set matches + + + align:start position:0% +make sure your basic rule set matches +the core experience you're trying to + + align:start position:0% +the core experience you're trying to + + + align:start position:0% +the core experience you're trying to +make with the game it's really really + + align:start position:0% +make with the game it's really really + + + align:start position:0% +make with the game it's really really +important for assignment two for this + + align:start position:0% +important for assignment two for this + + + align:start position:0% +important for assignment two for this +furnace month because that's what we + + align:start position:0% +furnace month because that's what we + + + align:start position:0% +furnace month because that's what we +said we set out right as we said come up + + align:start position:0% +said we set out right as we said come up + + + align:start position:0% +said we set out right as we said come up +with something that's going to have a + + align:start position:0% +with something that's going to have a + + + align:start position:0% +with something that's going to have a +very particular experience if you want + + align:start position:0% +very particular experience if you want + + + align:start position:0% +very particular experience if you want +the players to have at the end so if + + align:start position:0% +the players to have at the end so if + + + align:start position:0% +the players to have at the end so if +you're gonna do advanced rules and basic + + align:start position:0% +you're gonna do advanced rules and basic + + + align:start position:0% +you're gonna do advanced rules and basic +rules that criteria should be part of + + align:start position:0% +rules that criteria should be part of + + + align:start position:0% +rules that criteria should be part of +what your basic rules are the advanced + + align:start position:0% +what your basic rules are the advanced + + + align:start position:0% +what your basic rules are the advanced +rules as as Phil mentioned yes they for + + align:start position:0% +rules as as Phil mentioned yes they for + + + align:start position:0% +rules as as Phil mentioned yes they for +sometimes for some of them it could be + + align:start position:0% +sometimes for some of them it could be + + + align:start position:0% +sometimes for some of them it could be +it could add more interest it could be + + align:start position:0% +it could add more interest it could be + + + align:start position:0% +it could add more interest it could be +more see common intellectually + + align:start position:0% +more see common intellectually + + + align:start position:0% +more see common intellectually +stimulating but really the basic rules + + align:start position:0% +stimulating but really the basic rules + + + align:start position:0% +stimulating but really the basic rules +shouldn't support everything the game + + align:start position:0% +shouldn't support everything the game + + + align:start position:0% +shouldn't support everything the game +has that the advanced rules are just + + align:start position:0% +has that the advanced rules are just + + + align:start position:0% +has that the advanced rules are just +patents and actually if you don't want + + align:start position:0% +patents and actually if you don't want + + + align:start position:0% +patents and actually if you don't want +to send us in the ass rules don't just + + align:start position:0% +to send us in the ass rules don't just + + + align:start position:0% +to send us in the ass rules don't just +cut it cut it completely say we're not + + align:start position:0% +cut it cut it completely say we're not + + + align:start position:0% +cut it cut it completely say we're not +gonna we're not going to use the rules + + align:start position:0% +gonna we're not going to use the rules + + + align:start position:0% +gonna we're not going to use the rules +are in advanced rules because we just + + align:start position:0% +are in advanced rules because we just + + + align:start position:0% +are in advanced rules because we just +could not get them to work in time + + align:start position:0% +could not get them to work in time + + + align:start position:0% +could not get them to work in time +that's absolutely perfectly fine so long + + align:start position:0% +that's absolutely perfectly fine so long + + + align:start position:0% +that's absolutely perfectly fine so long +as this basically will still match the + + align:start position:0% +as this basically will still match the + + + align:start position:0% +as this basically will still match the +core experience you're trying to get + + align:start position:0% +core experience you're trying to get + + + align:start position:0% +core experience you're trying to get +across I think one thing I do want to + + align:start position:0% +across I think one thing I do want to + + + align:start position:0% +across I think one thing I do want to +add to that that for the most part basic + + align:start position:0% +add to that that for the most part basic + + + align:start position:0% +add to that that for the most part basic +rules are tricky time good yeah much + + align:start position:0% +rules are tricky time good yeah much + + + align:start position:0% +rules are tricky time good yeah much +better than a lot of the adventurers + + align:start position:0% +better than a lot of the adventurers + + + align:start position:0% +better than a lot of the adventurers +maybe because the the wording and the + + align:start position:0% +maybe because the the wording and the + + + align:start position:0% +maybe because the the wording and the +basic rules had a little bit more care + + align:start position:0% +basic rules had a little bit more care + + + align:start position:0% +basic rules had a little bit more care +maybe you tested if we found increasing + + align:start position:0% +maybe you tested if we found increasing + + + align:start position:0% +maybe you tested if we found increasing +games very playable and pretty enjoyable + + align:start position:0% +games very playable and pretty enjoyable + + + align:start position:0% +games very playable and pretty enjoyable +I was probably just fighting for + + align:start position:0% +I was probably just fighting for + + + align:start position:0% +I was probably just fighting for +so a lot of these something you had the + + align:start position:0% +so a lot of these something you had the + + + align:start position:0% +so a lot of these something you had the +adventurous + + align:start position:0% +adventurous + + + align:start position:0% +adventurous +I do realize some of those were things + + align:start position:0% +I do realize some of those were things + + + align:start position:0% +I do realize some of those were things +that came up in a testing process that + + align:start position:0% +that came up in a testing process that + + + align:start position:0% +that came up in a testing process that +you thought you know this is the game + + align:start position:0% +you thought you know this is the game + + + align:start position:0% +you thought you know this is the game +that our game has evolved into but once + + align:start position:0% +that our game has evolved into but once + + + align:start position:0% +that our game has evolved into but once +you do once it realize that there is a + + align:start position:0% +you do once it realize that there is a + + + align:start position:0% +you do once it realize that there is a +core game core basic game that works and + + align:start position:0% +core game core basic game that works and + + + align:start position:0% +core game core basic game that works and +then that this sort of like slightly + + align:start position:0% +then that this sort of like slightly + + + align:start position:0% +then that this sort of like slightly +more complicated version of the game + + align:start position:0% +more complicated version of the game + + + align:start position:0% +more complicated version of the game +that's slightly more complicated stuff + + align:start position:0% +that's slightly more complicated stuff + + + align:start position:0% +that's slightly more complicated stuff +is all candidates for cutting because + + align:start position:0% +is all candidates for cutting because + + + align:start position:0% +is all candidates for cutting because +you've already identified what the + + align:start position:0% +you've already identified what the + + + align:start position:0% +you've already identified what the +important one inside and they're only + + align:start position:0% +important one inside and they're only + + + align:start position:0% +important one inside and they're only +there basically when it comes to time + + align:start position:0% +there basically when it comes to time + + + align:start position:0% +there basically when it comes to time +any deadlines of course adopt a common + + align:start position:0% +any deadlines of course adopt a common + + + align:start position:0% +any deadlines of course adopt a common +lingo adopt a common language + + align:start position:0% +lingo adopt a common language + + + align:start position:0% +lingo adopt a common language +stick with it proofread your rules I + + align:start position:0% +stick with it proofread your rules I + + + align:start position:0% +stick with it proofread your rules I +think I have it written down the very + + align:start position:0% +think I have it written down the very + + + align:start position:0% +think I have it written down the very +bottom proofread cool so I'll say that a + + align:start position:0% +bottom proofread cool so I'll say that a + + + align:start position:0% +bottom proofread cool so I'll say that a +third time the airline and that means + + align:start position:0% +third time the airline and that means + + + align:start position:0% +third time the airline and that means +like naming conventions for the pieces + + align:start position:0% +like naming conventions for the pieces + + + align:start position:0% +like naming conventions for the pieces +for what you've chosen to call things in + + align:start position:0% +for what you've chosen to call things in + + + align:start position:0% +for what you've chosen to call things in +your game that could be naming + + align:start position:0% +your game that could be naming + + + align:start position:0% +your game that could be naming +conventions based on the rules but also + + align:start position:0% +conventions based on the rules but also + + + align:start position:0% +conventions based on the rules but also +proofreading your cards to making sure + + align:start position:0% +proofreading your cards to making sure + + + align:start position:0% +proofreading your cards to making sure +all your pieces are using the same + + align:start position:0% +all your pieces are using the same + + + align:start position:0% +all your pieces are using the same +language when it comes to talking about + + align:start position:0% +language when it comes to talking about + + + align:start position:0% +language when it comes to talking about +what the player does we did notice some + + align:start position:0% +what the player does we did notice some + + + align:start position:0% +what the player does we did notice some +some should versus may vs. must kind of + + align:start position:0% +some should versus may vs. must kind of + + + align:start position:0% +some should versus may vs. must kind of +getting mixed up so when we're playing + + align:start position:0% +getting mixed up so when we're playing + + + align:start position:0% +getting mixed up so when we're playing +the game I'm not quite sure + + align:start position:0% +the game I'm not quite sure + + + align:start position:0% +the game I'm not quite sure +well if I should do this if I may do + + align:start position:0% +well if I should do this if I may do + + + align:start position:0% +well if I should do this if I may do +this why is it if it's made here is a + + align:start position:0% +this why is it if it's made here is a + + + align:start position:0% +this why is it if it's made here is a +massive bang over here was it over + + align:start position:0% +massive bang over here was it over + + + align:start position:0% +massive bang over here was it over +here this wasn't quite quite sure wasn't + + align:start position:0% +here this wasn't quite quite sure wasn't + + + align:start position:0% +here this wasn't quite quite sure wasn't +what was it quite clear so I definitely + + align:start position:0% +what was it quite clear so I definitely + + + align:start position:0% +what was it quite clear so I definitely +recommend spending today working in a + + align:start position:0% +recommend spending today working in a + + + align:start position:0% +recommend spending today working in a +rule spend today having us play your + + align:start position:0% +rule spend today having us play your + + + align:start position:0% +rule spend today having us play your +game using your current rules and then + + align:start position:0% +game using your current rules and then + + + align:start position:0% +game using your current rules and then +taking our feedback and then and then + + align:start position:0% +taking our feedback and then and then + + + align:start position:0% +taking our feedback and then and then +work + + align:start position:0% +work + + + align:start position:0% +work +for trailing one thing and again when it + + align:start position:0% +for trailing one thing and again when it + + + align:start position:0% +for trailing one thing and again when it +comes to cutting things when you are + + align:start position:0% +comes to cutting things when you are + + + align:start position:0% +comes to cutting things when you are +cutting making sure that you are filling + + align:start position:0% +cutting making sure that you are filling + + + align:start position:0% +cutting making sure that you are filling +in the gaps so if you cut something out + + align:start position:0% +in the gaps so if you cut something out + + + align:start position:0% +in the gaps so if you cut something out +there might be a system there might be a + + align:start position:0% +there might be a system there might be a + + + align:start position:0% +there might be a system there might be a +rule in this case it's generally was + + align:start position:0% +rule in this case it's generally was + + + align:start position:0% +rule in this case it's generally was +polish issues so if something was + + align:start position:0% +polish issues so if something was + + + align:start position:0% +polish issues so if something was +removed from from from one of the rule + + align:start position:0% +removed from from from one of the rule + + + align:start position:0% +removed from from from one of the rule +sets we saw a little bit of remnants of + + align:start position:0% +sets we saw a little bit of remnants of + + + align:start position:0% +sets we saw a little bit of remnants of +it like spread spread in the rules so + + align:start position:0% +it like spread spread in the rules so + + + align:start position:0% +it like spread spread in the rules so +for instance if you're it's say you're + + align:start position:0% +for instance if you're it's say you're + + + align:start position:0% +for instance if you're it's say you're +one of those groups that had basic rules + + align:start position:0% +one of those groups that had basic rules + + + align:start position:0% +one of those groups that had basic rules +and advanced rules and use and you took + + align:start position:0% +and advanced rules and use and you took + + + align:start position:0% +and advanced rules and use and you took +the chunk of the game it moved into + + align:start position:0% +the chunk of the game it moved into + + + align:start position:0% +the chunk of the game it moved into +advanced rules because you rise the core + + align:start position:0% +advanced rules because you rise the core + + + align:start position:0% +advanced rules because you rise the core +base game was playable without that when + + align:start position:0% +base game was playable without that when + + + align:start position:0% +base game was playable without that when +your basic rules still refer to bits of + + align:start position:0% +your basic rules still refer to bits of + + + align:start position:0% +your basic rules still refer to bits of +the advanced rules and I guess really + + align:start position:0% +the advanced rules and I guess really + + + align:start position:0% +the advanced rules and I guess really +confusing because adventures are + + align:start position:0% +confusing because adventures are + + + align:start position:0% +confusing because adventures are +complete from the different section of + + align:start position:0% +complete from the different section of + + + align:start position:0% +complete from the different section of +their rules that we have for setup so if + + align:start position:0% +their rules that we have for setup so if + + + align:start position:0% +their rules that we have for setup so if +you're gonna have a setup section before + + align:start position:0% +you're gonna have a setup section before + + + align:start position:0% +you're gonna have a setup section before +your rules it's actually highly + + align:start position:0% +your rules it's actually highly + + + align:start position:0% +your rules it's actually highly +recommended having set up section that + + align:start position:0% +recommended having set up section that + + + align:start position:0% +recommended having set up section that +is split out that is different from your + + align:start position:0% +is split out that is different from your + + + align:start position:0% +is split out that is different from your +rule section so we know exactly how to + + align:start position:0% +rule section so we know exactly how to + + + align:start position:0% +rule section so we know exactly how to +setup the game include diagrams and + + align:start position:0% +setup the game include diagrams and + + + align:start position:0% +setup the game include diagrams and +photos where are you where two player + + align:start position:0% +photos where are you where two player + + + align:start position:0% +photos where are you where two player +sits what is the orientation of cards + + align:start position:0% +sits what is the orientation of cards + + + align:start position:0% +sits what is the orientation of cards +what art is what is if you have a card + + align:start position:0% +what art is what is if you have a card + + + align:start position:0% +what art is what is if you have a card +that has all this information on it what + + align:start position:0% +that has all this information on it what + + + align:start position:0% +that has all this information on it what +is that common information across all + + align:start position:0% +is that common information across all + + + align:start position:0% +is that common information across all +cards if you think about a Magic the + + align:start position:0% +cards if you think about a Magic the + + + align:start position:0% +cards if you think about a Magic the +Gathering cards and all the different + + align:start position:0% +Gathering cards and all the different + + + align:start position:0% +Gathering cards and all the different +icons hopefully yours cards aren't as + + align:start position:0% +icons hopefully yours cards aren't as + + + align:start position:0% +icons hopefully yours cards aren't as +complex but you'll have the same thing + + align:start position:0% +complex but you'll have the same thing + + + align:start position:0% +complex but you'll have the same thing +in the same place of all the cards and + + align:start position:0% +in the same place of all the cards and + + + align:start position:0% +in the same place of all the cards and +so you can then tell us what that thing + + align:start position:0% +so you can then tell us what that thing + + + align:start position:0% +so you can then tell us what that thing +is and why it's useful and how to use it + + align:start position:0% +is and why it's useful and how to use it + + + align:start position:0% +is and why it's useful and how to use it +hasn't played the game and in particular + + align:start position:0% +hasn't played the game and in particular + + + align:start position:0% +hasn't played the game and in particular +let your game tell us teach us the game + + align:start position:0% +let your game tell us teach us the game + + + align:start position:0% +let your game tell us teach us the game +how to play is possible if you've got + + align:start position:0% +how to play is possible if you've got + + + align:start position:0% +how to play is possible if you've got +time if not it should still be in the + + align:start position:0% +time if not it should still be in the + + + align:start position:0% +time if not it should still be in the +rules well you mean do I let your game + + align:start position:0% +rules well you mean do I let your game + + + align:start position:0% +rules well you mean do I let your game +teach us is the if you're gonna have a + + align:start position:0% +teach us is the if you're gonna have a + + + align:start position:0% +teach us is the if you're gonna have a +board the board has a lot of empty space + + align:start position:0% +board the board has a lot of empty space + + + align:start position:0% +board the board has a lot of empty space +on it you can put some of your rules + + align:start position:0% +on it you can put some of your rules + + + align:start position:0% +on it you can put some of your rules +into the board you can put some of the + + align:start position:0% +into the board you can put some of the + + + align:start position:0% +into the board you can put some of the +setup features into the board + + align:start position:0% +setup features into the board + + + align:start position:0% +setup features into the board +got time right now for free drools and + + align:start position:0% +got time right now for free drools and + + + align:start position:0% +got time right now for free drools and +turn in as many copies of your rules if + + align:start position:0% +turn in as many copies of your rules if + + + align:start position:0% +turn in as many copies of your rules if +you have players in your game so the + + align:start position:0% +you have players in your game so the + + + align:start position:0% +you have players in your game so the +assignment did say it's a set number of + + align:start position:0% +assignment did say it's a set number of + + + align:start position:0% +assignment did say it's a set number of +two three or four players for your game + + align:start position:0% +two three or four players for your game + + + align:start position:0% +two three or four players for your game +if it's a four player game give us four + + align:start position:0% +if it's a four player game give us four + + + align:start position:0% +if it's a four player game give us four +copies for your rules + + align:start position:0% + + + + align:start position:0% + +that's all the basic stuff yeah and then + + align:start position:0% +that's all the basic stuff yeah and then + + + align:start position:0% +that's all the basic stuff yeah and then +we'll have we'll be getting your + + align:start position:0% +we'll have we'll be getting your + + + align:start position:0% +we'll have we'll be getting your +feedback specifically about for each + + align:start position:0% +feedback specifically about for each + + + align:start position:0% +feedback specifically about for each +individual game tomorrow yeah we'll give + + align:start position:0% +individual game tomorrow yeah we'll give + + + align:start position:0% +individual game tomorrow yeah we'll give +you that before turning in I just want + + align:start position:0% +you that before turning in I just want + + + align:start position:0% +you that before turning in I just want +to clarify one thing what should be best + + align:start position:0% +to clarify one thing what should be best + + + align:start position:0% +to clarify one thing what should be best +I'm not sure because I'm trying to think + + align:start position:0% +I'm not sure because I'm trying to think + + + align:start position:0% +I'm not sure because I'm trying to think +of a more concrete example so it's like + + align:start position:0% +of a more concrete example so it's like + + + align:start position:0% +of a more concrete example so it's like +within your rules you say the player + + align:start position:0% +within your rules you say the player + + + align:start position:0% +within your rules you say the player +should move their piece his or her piece + + align:start position:0% +should move their piece his or her piece + + + align:start position:0% +should move their piece his or her piece +you know from from one square to another + + align:start position:0% +you know from from one square to another + + + align:start position:0% +you know from from one square to another +we're not quite sure whether you are + + align:start position:0% +we're not quite sure whether you are + + + align:start position:0% +we're not quite sure whether you are +describing this as a good strategy as + + align:start position:0% +describing this as a good strategy as + + + align:start position:0% +describing this as a good strategy as +something that the player you know will + + align:start position:0% +something that the player you know will + + + align:start position:0% +something that the player you know will +should generally be doing because it's + + align:start position:0% +should generally be doing because it's + + + align:start position:0% +should generally be doing because it's +going to put the player head on + + align:start position:0% +going to put the player head on + + + align:start position:0% +going to put the player head on +something that a player must be doing + + align:start position:0% +something that a player must be doing + + + align:start position:0% +something that a player must be doing +because the rules require the player to + + align:start position:0% +because the rules require the player to + + + align:start position:0% +because the rules require the player to +do this other thing + + align:start position:0% +do this other thing + + + align:start position:0% +do this other thing +shoulders are very very difficult work + + align:start position:0% +shoulders are very very difficult work + + + align:start position:0% +shoulders are very very difficult work +to figure out for us if you're going to + + align:start position:0% +to figure out for us if you're going to + + + align:start position:0% +to figure out for us if you're going to +be if possible tell me sometimes context + + align:start position:0% +be if possible tell me sometimes context + + + align:start position:0% +be if possible tell me sometimes context +explains it for you but it does + + align:start position:0% +explains it for you but it does + + + align:start position:0% +explains it for you but it does +buddy things more often than it helps I + + align:start position:0% +buddy things more often than it helps I + + + align:start position:0% +buddy things more often than it helps I +find short makes perfect sense and + + align:start position:0% +find short makes perfect sense and + + + align:start position:0% +find short makes perfect sense and +you're going to give an example you're + + align:start position:0% +you're going to give an example you're + + + align:start position:0% +you're going to give an example you're +going to give an example make it + + align:start position:0% +going to give an example make it + + + align:start position:0% +going to give an example make it +italicize make it obvious or even like + + align:start position:0% +italicize make it obvious or even like + + + align:start position:0% +italicize make it obvious or even like +immigrant debts + + align:start position:0% +immigrant debts + + + align:start position:0% +immigrant debts +yeah intense on a sidebar or something + + align:start position:0% +yeah intense on a sidebar or something + + + align:start position:0% +yeah intense on a sidebar or something +to make it clear that this is not + + align:start position:0% +to make it clear that this is not + + + align:start position:0% +to make it clear that this is not +actually part of the rules this is an + + align:start position:0% +actually part of the rules this is an + + + align:start position:0% +actually part of the rules this is an +example of how this set of the rules + + align:start position:0% +example of how this set of the rules + + + align:start position:0% +example of how this set of the rules +plays out I think it use words like + + align:start position:0% +plays out I think it use words like + + + align:start position:0% +plays out I think it use words like +short right you know player one should + + align:start position:0% +short right you know player one should + + + align:start position:0% +short right you know player one should +do this because you're describing a + + align:start position:0% +do this because you're describing a + + + align:start position:0% +do this because you're describing a +strategy you're not saying that the + + align:start position:0% +strategy you're not saying that the + + + align:start position:0% +strategy you're not saying that the +rules require this to happen + + align:start position:0% +rules require this to happen + + + align:start position:0% +rules require this to happen +must say must when it's must and if a + + align:start position:0% +must say must when it's must and if a + + + align:start position:0% +must say must when it's must and if a +player must do something + + align:start position:0% +player must do something + + + align:start position:0% +player must do something +something and when you say a play of me + + align:start position:0% +something and when you say a play of me + + + align:start position:0% +something and when you say a play of me +be very very clear of what else the play + + align:start position:0% +be very very clear of what else the play + + + align:start position:0% +be very very clear of what else the play +of being do say for instance it's one + + align:start position:0% +of being do say for instance it's one + + + align:start position:0% +of being do say for instance it's one +out of five different options you said + + align:start position:0% +out of five different options you said + + + align:start position:0% +out of five different options you said +yeah the player may do one of these five + + align:start position:0% +yeah the player may do one of these five + + + align:start position:0% +yeah the player may do one of these five +four five options for the point but the + + align:start position:0% +four five options for the point but the + + + align:start position:0% +four five options for the point but the +point of the point for the point for the + + align:start position:0% +point of the point for the point for the + + + align:start position:0% +point of the point for the point for the +point yeah the last bullet tuck point is + + align:start position:0% +point yeah the last bullet tuck point is + + + align:start position:0% +point yeah the last bullet tuck point is +probably like do nothing you know it's + + align:start position:0% +probably like do nothing you know it's + + + align:start position:0% +probably like do nothing you know it's +like if a game with us or there's + + align:start position:0% +like if a game with us or there's + + + align:start position:0% +like if a game with us or there's +something bullet points are really + + align:start position:0% +something bullet points are really + + + align:start position:0% +something bullet points are really +really useful if there's any kind of + + align:start position:0% +really useful if there's any kind of + + + align:start position:0% +really useful if there's any kind of +option either even if it's just like + + align:start position:0% +option either even if it's just like + + + align:start position:0% +option either even if it's just like +player may do this or this break out the + + align:start position:0% +player may do this or this break out the + + + align:start position:0% +player may do this or this break out the +or and its own line give it bold put a + + align:start position:0% +or and its own line give it bold put a + + + align:start position:0% +or and its own line give it bold put a +couple lines around it put the next + + align:start position:0% +couple lines around it put the next + + + align:start position:0% +couple lines around it put the next +thing that they can do the other thing + + align:start position:0% +thing that they can do the other thing + + + align:start position:0% +thing that they can do the other thing +they can do after it make it really + + align:start position:0% +they can do after it make it really + + + align:start position:0% +they can do after it make it really +really clear it's one or the other not + + align:start position:0% +really clear it's one or the other not + + + align:start position:0% +really clear it's one or the other not +both yeah yeah yeah that goes the same + + align:start position:0% +both yeah yeah yeah that goes the same + + + align:start position:0% +both yeah yeah yeah that goes the same +for not just the appeal you're pretty + + align:start position:0% +for not just the appeal you're pretty + + + align:start position:0% +for not just the appeal you're pretty +rulesheet proposal cards stuff on the + + align:start position:0% +rulesheet proposal cards stuff on the + + + align:start position:0% +rulesheet proposal cards stuff on the +board you know because sometimes there + + align:start position:0% +board you know because sometimes there + + + align:start position:0% +board you know because sometimes there +are games where you have options on the + + align:start position:0% +are games where you have options on the + + + align:start position:0% +are games where you have options on the +card right and you made us do this or + + align:start position:0% +card right and you made us do this or + + + align:start position:0% +card right and you made us do this or +you may do that it's not entirely + + align:start position:0% +you may do that it's not entirely + + + align:start position:0% +you may do that it's not entirely +obvious if say the card does both of + + align:start position:0% +obvious if say the card does both of + + + align:start position:0% +obvious if say the card does both of +those things or you've got to choose one + + align:start position:0% +those things or you've got to choose one + + + align:start position:0% +those things or you've got to choose one +of those things and who gets to choose + + align:start position:0% +of those things and who gets to choose + + + align:start position:0% +of those things and who gets to choose +one of those two things so that's + + align:start position:0% +one of those two things so that's + + + align:start position:0% +one of those two things so that's +something to keep in mind you only use + + align:start position:0% +something to keep in mind you only use + + + align:start position:0% +something to keep in mind you only use +numbered bullet points whatever one two + + align:start position:0% +numbered bullet points whatever one two + + + align:start position:0% +numbered bullet points whatever one two +three four + + align:start position:0% +three four + + + align:start position:0% +three four +if something is going to be sequential + + align:start position:0% +if something is going to be sequential + + + align:start position:0% +if something is going to be sequential +no it's good for things like here are + + align:start position:0% +no it's good for things like here are + + + align:start position:0% +no it's good for things like here are +the steps of a round of game play you + + align:start position:0% +the steps of a round of game play you + + + align:start position:0% +the steps of a round of game play you +know first you do this then you do this + + align:start position:0% +know first you do this then you do this + + + align:start position:0% +know first you do this then you do this +then you do this + + align:start position:0% +then you do this + + + align:start position:0% +then you do this +don't talk don't say the player may do + + align:start position:0% +don't talk don't say the player may do + + + align:start position:0% +don't talk don't say the player may do +one of the following 1.2.3 doctors like + + align:start position:0% +one of the following 1.2.3 doctors like + + + align:start position:0% +one of the following 1.2.3 doctors like +now in operation okay yeah then yeah + + align:start position:0% +now in operation okay yeah then yeah + + + align:start position:0% +now in operation okay yeah then yeah +then actually this part of rounds stages + + align:start position:0% +then actually this part of rounds stages + + + align:start position:0% +then actually this part of rounds stages +phases oh that's that's decibel Cabul + + align:start position:0% +phases oh that's that's decibel Cabul + + + align:start position:0% +phases oh that's that's decibel Cabul +area that yeah and yes + + align:start position:0% +area that yeah and yes + + + align:start position:0% +area that yeah and yes +choose one stick with it um proofread it + + align:start position:0% +choose one stick with it um proofread it + + + align:start position:0% +choose one stick with it um proofread it +and make sure you chose it make sure it + + align:start position:0% +and make sure you chose it make sure it + + + align:start position:0% +and make sure you chose it make sure it +works especially if you're gonna make + + align:start position:0% +works especially if you're gonna make + + + align:start position:0% +works especially if you're gonna make +any changes today and you're turning it + + align:start position:0% +any changes today and you're turning it + + + align:start position:0% +any changes today and you're turning it +in two days have somebody who is not you + + align:start position:0% +in two days have somebody who is not you + + + align:start position:0% +in two days have somebody who is not you +proofread it and make sure + + align:start position:0% +proofread it and make sure + + + align:start position:0% +proofread it and make sure +you're using the same language + + align:start position:0% +you're using the same language + + + align:start position:0% +you're using the same language +throughout rounds usually involves + + align:start position:0% +throughout rounds usually involves + + + align:start position:0% +throughout rounds usually involves +everybody around the table doing one + + align:start position:0% +everybody around the table doing one + + + align:start position:0% +everybody around the table doing one +thing in sequence the same sort of thing + + align:start position:0% +thing in sequence the same sort of thing + + + align:start position:0% +thing in sequence the same sort of thing +in sequence steps are really big you + + align:start position:0% +in sequence steps are really big you + + + align:start position:0% +in sequence steps are really big you +know + + align:start position:0% +know + + + align:start position:0% +know +phases so usually like describing large + + align:start position:0% +phases so usually like describing large + + + align:start position:0% +phases so usually like describing large +chunks of game but you know things like + + align:start position:0% +chunks of game but you know things like + + + align:start position:0% +chunks of game but you know things like +Oh opening candids bit gain and + + align:start position:0% +Oh opening candids bit gain and + + + align:start position:0% +Oh opening candids bit gain and +gain:feed Jesus and usually not using + + align:start position:0% +gain:feed Jesus and usually not using + + + align:start position:0% +gain:feed Jesus and usually not using +rules but I know that some game vixx + + align:start position:0% +rules but I know that some game vixx + + + align:start position:0% +rules but I know that some game vixx +game yeah 18 XS I know that's as + + align:start position:0% +game yeah 18 XS I know that's as + + + align:start position:0% +game yeah 18 XS I know that's as +business-wise maddening sweet but we + + align:start position:0% +business-wise maddening sweet but we + + + align:start position:0% +business-wise maddening sweet but we +continue to work on context steps + + align:start position:0% +continue to work on context steps + + + align:start position:0% +continue to work on context steps +especially it is a sequential sequence + + align:start position:0% +especially it is a sequential sequence + + + align:start position:0% +especially it is a sequential sequence +of things like this look this is my turn + + align:start position:0% +of things like this look this is my turn + + + align:start position:0% +of things like this look this is my turn +in or out and here are the three steps I + + align:start position:0% +in or out and here are the three steps I + + + align:start position:0% +in or out and here are the three steps I +get to do you know I draw step one draw + + align:start position:0% +get to do you know I draw step one draw + + + align:start position:0% +get to do you know I draw step one draw +a card step two choose a car cut my + + align:start position:0% +a card step two choose a car cut my + + + align:start position:0% +a card step two choose a car cut my +hands that three players right now + + align:start position:0% +hands that three players right now + + + align:start position:0% +hands that three players right now +things like that that that sort of us + + align:start position:0% +things like that that that sort of us + + + align:start position:0% +things like that that that sort of us +faces I've also included described in + + align:start position:0% +faces I've also included described in + + + align:start position:0% +faces I've also included described in +things like there is round round one is + + align:start position:0% +things like there is round round one is + + + align:start position:0% +things like there is round round one is +one kind of action and round twos it's + + align:start position:0% +one kind of action and round twos it's + + + align:start position:0% +one kind of action and round twos it's +like a completely different kind of + + align:start position:0% +like a completely different kind of + + + align:start position:0% +like a completely different kind of +action around three is gonna be demanded + + align:start position:0% +action around three is gonna be demanded + + + align:start position:0% +action around three is gonna be demanded +like faces and it's like oh my god + + align:start position:0% +like faces and it's like oh my god + + + align:start position:0% +like faces and it's like oh my god +that's that Palgrave does that actually + + align:start position:0% +that's that Palgrave does that actually + + + align:start position:0% +that's that Palgrave does that actually +yeah + + align:start position:0% + + + + align:start position:0% + +there are turns and yes yes this is why + + align:start position:0% +there are turns and yes yes this is why + + + align:start position:0% +there are turns and yes yes this is why +the game is thank you so much harder to + + align:start position:0% +the game is thank you so much harder to + + + align:start position:0% +the game is thank you so much harder to +learn that in a safety play to play let + + align:start position:0% +learn that in a safety play to play let + + + align:start position:0% +learn that in a safety play to play let +me not at hurt but when Davis case yeah + + align:start position:0% +me not at hurt but when Davis case yeah + + + align:start position:0% +me not at hurt but when Davis case yeah +so so that's why faces complete called + + align:start position:0% +so so that's why faces complete called + + + align:start position:0% +so so that's why faces complete called +complicate things sometimes the + + align:start position:0% +complicate things sometimes the + + + align:start position:0% +complicate things sometimes the +disinfect the right word but it's just + + align:start position:0% +disinfect the right word but it's just + + + align:start position:0% +disinfect the right word but it's just +hard to be able to convince to expect at + + align:start position:0% +hard to be able to convince to expect at + + + align:start position:0% +hard to be able to convince to expect at +every single player the code you put + + align:start position:0% +every single player the code you put + + + align:start position:0% +every single player the code you put +that word the same way okay so you can + + align:start position:0% +that word the same way okay so you can + + + align:start position:0% +that word the same way okay so you can +break up new teams keep working on your + + align:start position:0% +break up new teams keep working on your + + + align:start position:0% +break up new teams keep working on your +games + + align:start position:0% +games + + + align:start position:0% +games +this is play test its time so in + + align:start position:0% +this is play test its time so in + + + align:start position:0% +this is play test its time so in +particular play test your rules if you + + align:start position:0% +particular play test your rules if you + + + align:start position:0% +particular play test your rules if you +want us to play your play your rules and + + align:start position:0% +want us to play your play your rules and + + + align:start position:0% +want us to play your play your rules and +give you feedback before you turn in + + align:start position:0% +give you feedback before you turn in + + + align:start position:0% +give you feedback before you turn in +today's the day to do it cheats right + + align:start position:0% +today's the day to do it cheats right + + + align:start position:0% +today's the day to do it cheats right +there she's over there \ No newline at end of file diff --git a/DdY98Zaff5I.txt b/DdY98Zaff5I.txt new file mode 100644 index 0000000000000000000000000000000000000000..0cd96bedff97f2b12823897326ff9b351ea2681e --- /dev/null +++ b/DdY98Zaff5I.txt @@ -0,0 +1,15515 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a creative commons license + + align:start position:0% +a creative commons license + + + align:start position:0% +a creative commons license +your support will help mit + + align:start position:0% +your support will help mit + + + align:start position:0% +your support will help mit +opencourseware continue to offer high + + align:start position:0% +opencourseware continue to offer high + + + align:start position:0% +opencourseware continue to offer high +quality educational resources for free + + align:start position:0% +quality educational resources for free + + + align:start position:0% +quality educational resources for free +to make a donation or view additional + + align:start position:0% +to make a donation or view additional + + + align:start position:0% +to make a donation or view additional +materials from hundreds of mit courses + + align:start position:0% +materials from hundreds of mit courses + + + align:start position:0% +materials from hundreds of mit courses +visit mit open courseware at ocw.mit.edu + + align:start position:0% + + + + align:start position:0% + +okay so + + align:start position:0% +okay so + + + align:start position:0% +okay so +let me remind you + + align:start position:0% +let me remind you + + + align:start position:0% +let me remind you +where we were before spring break + + align:start position:0% +where we were before spring break + + + align:start position:0% +where we were before spring break +so first of all + + align:start position:0% +so first of all + + + align:start position:0% +so first of all +there's a posting with the projects list + + align:start position:0% +there's a posting with the projects list + + + align:start position:0% +there's a posting with the projects list +um + + align:start position:0% +um + + + align:start position:0% +um +feel free to pick a project as soon as + + align:start position:0% +feel free to pick a project as soon as + + + align:start position:0% +feel free to pick a project as soon as +you're ready + + align:start position:0% +you're ready + + + align:start position:0% +you're ready +send me your choice + + align:start position:0% +send me your choice + + + align:start position:0% +send me your choice +problem set number three do today + + align:start position:0% +problem set number three do today + + + align:start position:0% +problem set number three do today +problem set number four is posted this + + align:start position:0% +problem set number four is posted this + + + align:start position:0% +problem set number four is posted this +morning + + align:start position:0% +morning + + + align:start position:0% +morning +it will be due + + align:start position:0% +it will be due + + + align:start position:0% +it will be due +in two weeks plus two days so two weeks + + align:start position:0% +in two weeks plus two days so two weeks + + + align:start position:0% +in two weeks plus two days so two weeks +from now there's actually a holiday so + + align:start position:0% +from now there's actually a holiday so + + + align:start position:0% +from now there's actually a holiday so +we'll be doing that thursday + + align:start position:0% +we'll be doing that thursday + + + align:start position:0% +we'll be doing that thursday +last time we were talking about two + + align:start position:0% +last time we were talking about two + + + align:start position:0% +last time we were talking about two +nucleon effective field theory + + align:start position:0% +nucleon effective field theory + + + align:start position:0% +nucleon effective field theory +so this was a non-relativistic field + + align:start position:0% +so this was a non-relativistic field + + + align:start position:0% +so this was a non-relativistic field +theory both of these terms here in the + + align:start position:0% +theory both of these terms here in the + + + align:start position:0% +theory both of these terms here in the +action were the same size they were the + + align:start position:0% +action were the same size they were the + + + align:start position:0% +action were the same size they were the +same relevance + + align:start position:0% + + + + align:start position:0% + +and we talked about that last time + + align:start position:0% +and we talked about that last time + + + align:start position:0% +and we talked about that last time +so in hqt it would just be the first + + align:start position:0% +so in hqt it would just be the first + + + align:start position:0% +so in hqt it would just be the first +term but in this case of two nucleons we + + align:start position:0% +term but in this case of two nucleons we + + + align:start position:0% +term but in this case of two nucleons we +actually need the kinetic term as well + + align:start position:0% +actually need the kinetic term as well + + + align:start position:0% +actually need the kinetic term as well +and both of these terms are equally + + align:start position:0% +and both of these terms are equally + + + align:start position:0% +and both of these terms are equally +important + + align:start position:0% +important + + + align:start position:0% +important +and that basically means that in this + + align:start position:0% +and that basically means that in this + + + align:start position:0% +and that basically means that in this +type of system the time derivatives and + + align:start position:0% +type of system the time derivatives and + + + align:start position:0% +type of system the time derivatives and +spatial derivatives are counted + + align:start position:0% +spatial derivatives are counted + + + align:start position:0% +spatial derivatives are counted +differently but you can organize the + + align:start position:0% +differently but you can organize the + + + align:start position:0% +differently but you can organize the +field there using equations of motion so + + align:start position:0% +field there using equations of motion so + + + align:start position:0% +field there using equations of motion so +that these are just local operators with + + align:start position:0% +that these are just local operators with + + + align:start position:0% +that these are just local operators with +spatial derivatives + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +you basically deal with the time + + align:start position:0% +you basically deal with the time + + + align:start position:0% +you basically deal with the time +derivatives once and for all and you + + align:start position:0% +derivatives once and for all and you + + + align:start position:0% +derivatives once and for all and you +could always use equations of motion to + + align:start position:0% +could always use equations of motion to + + + align:start position:0% +could always use equations of motion to +eliminate them there + + align:start position:0% +eliminate them there + + + align:start position:0% +eliminate them there +and so you just have really this one + + align:start position:0% +and so you just have really this one + + + align:start position:0% +and so you just have really this one +time derivative + + align:start position:0% +time derivative + + + align:start position:0% +time derivative +this theory is particularly simple if we + + align:start position:0% +this theory is particularly simple if we + + + align:start position:0% +this theory is particularly simple if we +neglect the relativistic corrections + + align:start position:0% +neglect the relativistic corrections + + + align:start position:0% +neglect the relativistic corrections +and that's because it's not because it's + + align:start position:0% +and that's because it's not because it's + + + align:start position:0% +and that's because it's not because it's +a non-relativistic field theory the + + align:start position:0% +a non-relativistic field theory the + + + align:start position:0% +a non-relativistic field theory the +bubble we just have these bubble + + align:start position:0% +bubble we just have these bubble + + + align:start position:0% +bubble we just have these bubble +diagrams + + align:start position:0% +diagrams + + + align:start position:0% +diagrams +and they're just contact interactions so + + align:start position:0% +and they're just contact interactions so + + + align:start position:0% +and they're just contact interactions so +they all decouple from each other so at + + align:start position:0% +they all decouple from each other so at + + + align:start position:0% +they all decouple from each other so at +n loop order we can just write down what + + align:start position:0% +n loop order we can just write down what + + + align:start position:0% +n loop order we can just write down what +the loops are + + align:start position:0% +the loops are + + + align:start position:0% +the loops are +we talked about the fact that + + align:start position:0% +we talked about the fact that + + + align:start position:0% +we talked about the fact that +in terms of power counting things were + + align:start position:0% +in terms of power counting things were + + + align:start position:0% +in terms of power counting things were +could be a little subtle + + align:start position:0% +could be a little subtle + + + align:start position:0% +could be a little subtle +and that was related also to a power + + align:start position:0% +and that was related also to a power + + + align:start position:0% +and that was related also to a power +divergence that occurs in this diagram + + align:start position:0% +divergence that occurs in this diagram + + + align:start position:0% +divergence that occurs in this diagram +and we could track that power divergence + + align:start position:0% +and we could track that power divergence + + + align:start position:0% +and we could track that power divergence +by using particular schemes that gave + + align:start position:0% +by using particular schemes that gave + + + align:start position:0% +by using particular schemes that gave +this extra mu r term and i won't repeat + + align:start position:0% +this extra mu r term and i won't repeat + + + align:start position:0% +this extra mu r term and i won't repeat +all that story but + + align:start position:0% +all that story but + + + align:start position:0% +all that story but +that led us to adding a finite counter + + align:start position:0% +that led us to adding a finite counter + + + align:start position:0% +that led us to adding a finite counter +term to this bubble diagram to track the + + align:start position:0% +term to this bubble diagram to track the + + + align:start position:0% +term to this bubble diagram to track the +power law divergent term + + align:start position:0% +power law divergent term + + + align:start position:0% +power law divergent term +and that allowed us to come up with a + + align:start position:0% +and that allowed us to come up with a + + + align:start position:0% +and that allowed us to come up with a +counting power counting that would take + + align:start position:0% +counting power counting that would take + + + align:start position:0% +counting power counting that would take +into account systems where the + + align:start position:0% +into account systems where the + + + align:start position:0% +into account systems where the +scattering length is large or in + + align:start position:0% +scattering length is large or in + + + align:start position:0% +scattering length is large or in +particular the scattering length times + + align:start position:0% +particular the scattering length times + + + align:start position:0% +particular the scattering length times +the momentum is greater than one and in + + align:start position:0% +the momentum is greater than one and in + + + align:start position:0% +the momentum is greater than one and in +these two nucleon systems that's exactly + + align:start position:0% +these two nucleon systems that's exactly + + + align:start position:0% +these two nucleon systems that's exactly +the scenario that we're in + + align:start position:0% +the scenario that we're in + + + align:start position:0% +the scenario that we're in +so what we then had was a power counting + + align:start position:0% +so what we then had was a power counting + + + align:start position:0% +so what we then had was a power counting +that assigned the very first operator + + align:start position:0% +that assigned the very first operator + + + align:start position:0% +that assigned the very first operator +to scale like one over a power of + + align:start position:0% +to scale like one over a power of + + + align:start position:0% +to scale like one over a power of +momentum + + align:start position:0% +momentum + + + align:start position:0% +momentum +so not like a one over a power of a + + align:start position:0% +so not like a one over a power of a + + + align:start position:0% +so not like a one over a power of a +large scale but actually one over a + + align:start position:0% +large scale but actually one over a + + + align:start position:0% +large scale but actually one over a +power of something small the momentum + + align:start position:0% +power of something small the momentum + + + align:start position:0% +power of something small the momentum +that we're interested in studying so + + align:start position:0% +that we're interested in studying so + + + align:start position:0% +that we're interested in studying so +it's enhanced + + align:start position:0% + + + + align:start position:0% + +in the power counting that we wanted to + + align:start position:0% +in the power counting that we wanted to + + + align:start position:0% +in the power counting that we wanted to +adopt and that meant basically that you + + align:start position:0% +adopt and that meant basically that you + + + align:start position:0% +adopt and that meant basically that you +had to treat this one coupling c0 + + align:start position:0% +had to treat this one coupling c0 + + + align:start position:0% +had to treat this one coupling c0 +non-perturbatively + + align:start position:0% +non-perturbatively + + + align:start position:0% +non-perturbatively +you summed it up to all orders so the + + align:start position:0% +you summed it up to all orders so the + + + align:start position:0% +you summed it up to all orders so the +term here + + align:start position:0% +term here + + + align:start position:0% +term here +comes from adding up all the diagrams + + align:start position:0% + + + + align:start position:0% + +with any number of bubbles + + align:start position:0% +with any number of bubbles + + + align:start position:0% +with any number of bubbles +and that all give this first term + + align:start position:0% +and that all give this first term + + + align:start position:0% +and that all give this first term +and then the rest of the couplings are + + align:start position:0% +and then the rest of the couplings are + + + align:start position:0% +and then the rest of the couplings are +treated perturbatively the higher + + align:start position:0% +treated perturbatively the higher + + + align:start position:0% +treated perturbatively the higher +derivative term so a term c2 which comes + + align:start position:0% +derivative term so a term c2 which comes + + + align:start position:0% +derivative term so a term c2 which comes +with + + align:start position:0% +with + + + align:start position:0% +with +a grad squared and that gives us extra p + + align:start position:0% +a grad squared and that gives us extra p + + + align:start position:0% +a grad squared and that gives us extra p +squared and the numerator here gets + + align:start position:0% +squared and the numerator here gets + + + align:start position:0% +squared and the numerator here gets +treated uh perturbatively and there's + + align:start position:0% +treated uh perturbatively and there's + + + align:start position:0% +treated uh perturbatively and there's +this term and then there's higher terms + + align:start position:0% +this term and then there's higher terms + + + align:start position:0% +this term and then there's higher terms +and that's how we could organize this + + align:start position:0% +and that's how we could organize this + + + align:start position:0% +and that's how we could organize this +theory and this sums up all these powers + + align:start position:0% +theory and this sums up all these powers + + + align:start position:0% +theory and this sums up all these powers +of a times p + + align:start position:0% +of a times p + + + align:start position:0% +of a times p +these denominators that i'm showing you + + align:start position:0% +these denominators that i'm showing you + + + align:start position:0% +these denominators that i'm showing you +there + + align:start position:0% +there + + + align:start position:0% +there +so what i want to do for the first part + + align:start position:0% +so what i want to do for the first part + + + align:start position:0% +so what i want to do for the first part +of today is just really continue with + + align:start position:0% +of today is just really continue with + + + align:start position:0% +of today is just really continue with +this this effective field theory + + align:start position:0% +this this effective field theory + + + align:start position:0% +this this effective field theory +and talk about a few more of its + + align:start position:0% +and talk about a few more of its + + + align:start position:0% +and talk about a few more of its +features + + align:start position:0% + + + + align:start position:0% + +first i want to talk start with + + align:start position:0% +first i want to talk start with + + + align:start position:0% +first i want to talk start with +symmetries and then we'll talk about + + align:start position:0% +symmetries and then we'll talk about + + + align:start position:0% +symmetries and then we'll talk about +something called the deuteron + + align:start position:0% +something called the deuteron + + + align:start position:0% +something called the deuteron +yeah + + align:start position:0% +yeah + + + align:start position:0% +yeah +there's a question about the + + align:start position:0% +there's a question about the + + + align:start position:0% +there's a question about the +relevance of the kinetic term yeah so + + align:start position:0% +relevance of the kinetic term yeah so + + + align:start position:0% +relevance of the kinetic term yeah so +other than getting a pinching on your + + align:start position:0% +other than getting a pinching on your + + + align:start position:0% +other than getting a pinching on your +integrals is there + + align:start position:0% +integrals is there + + + align:start position:0% +integrals is there +i don't know a more power counting + + align:start position:0% +i don't know a more power counting + + + align:start position:0% +i don't know a more power counting +friendly kind of argument yeah so you + + align:start position:0% +friendly kind of argument yeah so you + + + align:start position:0% +friendly kind of argument yeah so you +can think about it like really what + + align:start position:0% +can think about it like really what + + + align:start position:0% +can think about it like really what +we're doing here is non-relativistic + + align:start position:0% +we're doing here is non-relativistic + + + align:start position:0% +we're doing here is non-relativistic +quantum mechanics + + align:start position:0% +quantum mechanics + + + align:start position:0% +quantum mechanics +and + + align:start position:0% +and + + + align:start position:0% +and +uh if you think about non-relativistic + + align:start position:0% +uh if you think about non-relativistic + + + align:start position:0% +uh if you think about non-relativistic +quantum connects you think about like + + align:start position:0% +quantum connects you think about like + + + align:start position:0% +quantum connects you think about like +the viral theorem you're used to + + align:start position:0% +the viral theorem you're used to + + + align:start position:0% +the viral theorem you're used to +thinking about the fact that kinetic + + align:start position:0% +thinking about the fact that kinetic + + + align:start position:0% +thinking about the fact that kinetic +energy and potential energy are equally + + align:start position:0% +energy and potential energy are equally + + + align:start position:0% +energy and potential energy are equally +relevant + + align:start position:0% +relevant + + + align:start position:0% +relevant +right so from a physics standpoint if i + + align:start position:0% +right so from a physics standpoint if i + + + align:start position:0% +right so from a physics standpoint if i +didn't want to + + align:start position:0% +didn't want to + + + align:start position:0% +didn't want to +talk about diagrams or + + align:start position:0% +talk about diagrams or + + + align:start position:0% +talk about diagrams or +i just wanted to make a physics argument + + align:start position:0% +i just wanted to make a physics argument + + + align:start position:0% +i just wanted to make a physics argument +for why that would be the right thing to + + align:start position:0% +for why that would be the right thing to + + + align:start position:0% +for why that would be the right thing to +do + + align:start position:0% +do + + + align:start position:0% +do +i could simply tell you + + align:start position:0% +i could simply tell you + + + align:start position:0% +i could simply tell you +i want non-relativistic quantum + + align:start position:0% +i want non-relativistic quantum + + + align:start position:0% +i want non-relativistic quantum +mechanics at lowest order this is a + + align:start position:0% +mechanics at lowest order this is a + + + align:start position:0% +mechanics at lowest order this is a +system with two heavy particles and + + align:start position:0% +system with two heavy particles and + + + align:start position:0% +system with two heavy particles and +that's what the physics should be + + align:start position:0% +that's what the physics should be + + + align:start position:0% +that's what the physics should be +if you start with the wrong theory then + + align:start position:0% +if you start with the wrong theory then + + + align:start position:0% +if you start with the wrong theory then +you run into problems and that's kind of + + align:start position:0% +you run into problems and that's kind of + + + align:start position:0% +you run into problems and that's kind of +what we saw if we started with an hqt + + align:start position:0% +what we saw if we started with an hqt + + + align:start position:0% +what we saw if we started with an hqt +like reasoning + + align:start position:0% +like reasoning + + + align:start position:0% +like reasoning +and we see this pinch singularity + + align:start position:0% + + + + align:start position:0% + +which is resolved by the kinetic term + + align:start position:0% +which is resolved by the kinetic term + + + align:start position:0% +which is resolved by the kinetic term +okay why is it that non-ultimate quantum + + align:start position:0% +okay why is it that non-ultimate quantum + + + align:start position:0% +okay why is it that non-ultimate quantum +mechanics has the form that does that + + align:start position:0% +mechanics has the form that does that + + + align:start position:0% +mechanics has the form that does that +um + + align:start position:0% +um + + + align:start position:0% +um +why does non-relativistic quantum + + align:start position:0% +why does non-relativistic quantum + + + align:start position:0% +why does non-relativistic quantum +mechanics have the form that it does + + align:start position:0% +mechanics have the form that it does + + + align:start position:0% +mechanics have the form that it does +yeah so + + align:start position:0% +yeah so + + + align:start position:0% +yeah so +think about think about it from the + + align:start position:0% +think about think about it from the + + + align:start position:0% +think about think about it from the +following point of view so when when we + + align:start position:0% +following point of view so when when we + + + align:start position:0% +following point of view so when when we +just had this term + + align:start position:0% +just had this term + + + align:start position:0% +just had this term +what was the new what was the particle + + align:start position:0% +what was the new what was the particle + + + align:start position:0% +what was the new what was the particle +doing + + align:start position:0% +doing + + + align:start position:0% +doing +when we just had the partial t term we + + align:start position:0% +when we just had the partial t term we + + + align:start position:0% +when we just had the partial t term we +it's like a source we had a single + + align:start position:0% +it's like a source we had a single + + + align:start position:0% +it's like a source we had a single +source + + align:start position:0% +source + + + align:start position:0% +source +sitting there and we were interacting + + align:start position:0% +sitting there and we were interacting + + + align:start position:0% +sitting there and we were interacting +with it with some white stuff that was + + align:start position:0% +with it with some white stuff that was + + + align:start position:0% +with it with some white stuff that was +hqet + + align:start position:0% +hqet + + + align:start position:0% +hqet +here we have two sources + + align:start position:0% +here we have two sources + + + align:start position:0% +here we have two sources +and they have to interact with each + + align:start position:0% +and they have to interact with each + + + align:start position:0% +and they have to interact with each +other and the problem is that two + + align:start position:0% +other and the problem is that two + + + align:start position:0% +other and the problem is that two +sources interacting with each other + + align:start position:0% +sources interacting with each other + + + align:start position:0% +sources interacting with each other +really the kinetic energy is becomes a + + align:start position:0% +really the kinetic energy is becomes a + + + align:start position:0% +really the kinetic energy is becomes a +relevant + + align:start position:0% +relevant + + + align:start position:0% +relevant +thing it's not + + align:start position:0% +thing it's not + + + align:start position:0% +thing it's not +i mean it's actually a little more + + align:start position:0% +i mean it's actually a little more + + + align:start position:0% +i mean it's actually a little more +subtle than that + + align:start position:0% +subtle than that + + + align:start position:0% +subtle than that +if you really want to go into it in a + + align:start position:0% +if you really want to go into it in a + + + align:start position:0% +if you really want to go into it in a +gauge theory there's sort of situations + + align:start position:0% +gauge theory there's sort of situations + + + align:start position:0% +gauge theory there's sort of situations +where these two heavy sources act like + + align:start position:0% +where these two heavy sources act like + + + align:start position:0% +where these two heavy sources act like +two heavy sources like hqet and there's + + align:start position:0% +two heavy sources like hqet and there's + + + align:start position:0% +two heavy sources like hqet and there's +situations where they wiggle + + align:start position:0% +situations where they wiggle + + + align:start position:0% +situations where they wiggle +and the situations where they wiggle are + + align:start position:0% +and the situations where they wiggle are + + + align:start position:0% +and the situations where they wiggle are +exactly the things that the schrodinger + + align:start position:0% +exactly the things that the schrodinger + + + align:start position:0% +exactly the things that the schrodinger +equation is giving you + + align:start position:0% +equation is giving you + + + align:start position:0% +equation is giving you +um + + align:start position:0% +um + + + align:start position:0% +um +if you like + + align:start position:0% +if you like + + + align:start position:0% +if you like +yeah so that to say it precisely + + align:start position:0% +yeah so that to say it precisely + + + align:start position:0% +yeah so that to say it precisely +the potential that between the two heavy + + align:start position:0% +the potential that between the two heavy + + + align:start position:0% +the potential that between the two heavy +particles for the purposes of figuring + + align:start position:0% +particles for the purposes of figuring + + + align:start position:0% +particles for the purposes of figuring +out that potential you can treat them as + + align:start position:0% +out that potential you can treat them as + + + align:start position:0% +out that potential you can treat them as +static and fixed + + align:start position:0% +static and fixed + + + align:start position:0% +static and fixed +but then once you have that potential + + align:start position:0% +but then once you have that potential + + + align:start position:0% +but then once you have that potential +these bubble diagrams are kind of the + + align:start position:0% +these bubble diagrams are kind of the + + + align:start position:0% +these bubble diagrams are kind of the +way in which + + align:start position:0% +way in which + + + align:start position:0% +way in which +that potential gets iterated into the + + align:start position:0% +that potential gets iterated into the + + + align:start position:0% +that potential gets iterated into the +thing that you would get from solving + + align:start position:0% +thing that you would get from solving + + + align:start position:0% +thing that you would get from solving +the schrodinger equation so solving the + + align:start position:0% +the schrodinger equation so solving the + + + align:start position:0% +the schrodinger equation so solving the +shorter equation you're effectively + + align:start position:0% +shorter equation you're effectively + + + align:start position:0% +shorter equation you're effectively +treating the potential to all orders in + + align:start position:0% +treating the potential to all orders in + + + align:start position:0% +treating the potential to all orders in +this series exactly this bubble series + + align:start position:0% +this series exactly this bubble series + + + align:start position:0% +this series exactly this bubble series +and when you solve that you need to + + align:start position:0% +and when you solve that you need to + + + align:start position:0% +and when you solve that you need to +include the kinetic this grad squared + + align:start position:0% +include the kinetic this grad squared + + + align:start position:0% +include the kinetic this grad squared +over 2m for the same reason that it's a + + align:start position:0% +over 2m for the same reason that it's a + + + align:start position:0% +over 2m for the same reason that it's a +relevant thing to include in + + align:start position:0% +relevant thing to include in + + + align:start position:0% +relevant thing to include in +quantum mechanics + + align:start position:0% +quantum mechanics + + + align:start position:0% +quantum mechanics +okay + + align:start position:0% +okay + + + align:start position:0% +okay +good good project choice + + align:start position:0% +good good project choice + + + align:start position:0% +good good project choice +i urge you + + align:start position:0% + + + + align:start position:0% + +okay so let's talk about some of the + + align:start position:0% +okay so let's talk about some of the + + + align:start position:0% +okay so let's talk about some of the +symmetries of this theory which are kind + + align:start position:0% +symmetries of this theory which are kind + + + align:start position:0% +symmetries of this theory which are kind +of interesting + + align:start position:0% + + + + align:start position:0% + +so the first one is that this syria + + align:start position:0% +so the first one is that this syria + + + align:start position:0% +so the first one is that this syria +actually has a + + align:start position:0% +actually has a + + + align:start position:0% +actually has a +non-relativistic conformal invariance + + align:start position:0% + + + + align:start position:0% + +so what is a non-relativistic conformal + + align:start position:0% +so what is a non-relativistic conformal + + + align:start position:0% +so what is a non-relativistic conformal +invariant so this is + + align:start position:0% +invariant so this is + + + align:start position:0% +invariant so this is +an extension of the galilean group + + align:start position:0% + + + + align:start position:0% + +rather than the poincare group + + align:start position:0% + + + + align:start position:0% + +so we have the usual translations + + align:start position:0% + + + + align:start position:0% + +we have rotations + + align:start position:0% + + + + align:start position:0% + +we don't have lorenz boost but we do + + align:start position:0% +we don't have lorenz boost but we do + + + align:start position:0% +we don't have lorenz boost but we do +have galilean boost for a + + align:start position:0% +have galilean boost for a + + + align:start position:0% +have galilean boost for a +non-relativistic + + align:start position:0% +non-relativistic + + + align:start position:0% +non-relativistic +system like this + + align:start position:0% +system like this + + + align:start position:0% +system like this +so what would those be + + align:start position:0% + + + + align:start position:0% + +so under a galilean boost time is not + + align:start position:0% +so under a galilean boost time is not + + + align:start position:0% +so under a galilean boost time is not +changed and the spatial coordinates are + + align:start position:0% +changed and the spatial coordinates are + + + align:start position:0% +changed and the spatial coordinates are +changed + + align:start position:0% + + + + align:start position:0% + +and then there's additional generators + + align:start position:0% +and then there's additional generators + + + align:start position:0% +and then there's additional generators +that you have in this conformal for a + + align:start position:0% +that you have in this conformal for a + + + align:start position:0% +that you have in this conformal for a +conformal invariants + + align:start position:0% +conformal invariants + + + align:start position:0% +conformal invariants +one is a scale transformation + + align:start position:0% +one is a scale transformation + + + align:start position:0% +one is a scale transformation +one generator + + align:start position:0% +one generator + + + align:start position:0% +one generator +and the way that the scale + + align:start position:0% +and the way that the scale + + + align:start position:0% +and the way that the scale +transformation works is as follows + + align:start position:0% +transformation works is as follows + + + align:start position:0% +transformation works is as follows +you rescale the coordinates by some + + align:start position:0% +you rescale the coordinates by some + + + align:start position:0% +you rescale the coordinates by some +let's call it e to the s + + align:start position:0% +let's call it e to the s + + + align:start position:0% +let's call it e to the s +but you have to rescale time differently + + align:start position:0% + + + + align:start position:0% + +by e to the 2s + + align:start position:0% +by e to the 2s + + + align:start position:0% +by e to the 2s +and the reason that you have to do that + + align:start position:0% +and the reason that you have to do that + + + align:start position:0% +and the reason that you have to do that +is exactly because + + align:start position:0% +is exactly because + + + align:start position:0% +is exactly because +these two terms should be treated the + + align:start position:0% +these two terms should be treated the + + + align:start position:0% +these two terms should be treated the +same + + align:start position:0% +same + + + align:start position:0% +same +so you have to rescale time + + align:start position:0% +so you have to rescale time + + + align:start position:0% +so you have to rescale time +twice as much as you rescale the spatial + + align:start position:0% +twice as much as you rescale the spatial + + + align:start position:0% +twice as much as you rescale the spatial +derivatives if you like + + align:start position:0% +derivatives if you like + + + align:start position:0% +derivatives if you like +so that's what gives rise to the two + + align:start position:0% +so that's what gives rise to the two + + + align:start position:0% +so that's what gives rise to the two +there + + align:start position:0% +there + + + align:start position:0% +there +and that just goes to the heart of sort + + align:start position:0% +and that just goes to the heart of sort + + + align:start position:0% +and that just goes to the heart of sort +of counting time and + + align:start position:0% +of counting time and + + + align:start position:0% +of counting time and +space + + align:start position:0% +space + + + align:start position:0% +space +differently + + align:start position:0% + + + + align:start position:0% + +and then finally there's there isn't a + + align:start position:0% +and then finally there's there isn't a + + + align:start position:0% +and then finally there's there isn't a +conformal generator + + align:start position:0% + + + + align:start position:0% + +and there's actually only one generator + + align:start position:0% +and there's actually only one generator + + + align:start position:0% +and there's actually only one generator +in this non-relativistic case + + align:start position:0% + + + + align:start position:0% + +and basically what this generator + + align:start position:0% +and basically what this generator + + + align:start position:0% +and basically what this generator +corresponds to is it + + align:start position:0% +corresponds to is it + + + align:start position:0% +corresponds to is it +a shift of inverse time + + align:start position:0% +a shift of inverse time + + + align:start position:0% +a shift of inverse time +and then a corresponding change to the + + align:start position:0% +and then a corresponding change to the + + + align:start position:0% +and then a corresponding change to the +coordinates + + align:start position:0% +coordinates + + + align:start position:0% +coordinates +and if you take all these things + + align:start position:0% +and if you take all these things + + + align:start position:0% +and if you take all these things +together it's actually something called + + align:start position:0% +together it's actually something called + + + align:start position:0% +together it's actually something called +the schrodinger group + + align:start position:0% + + + + align:start position:0% + +and the theory we've been talking about + + align:start position:0% +and the theory we've been talking about + + + align:start position:0% +and the theory we've been talking about +actually has this non-relativistic + + align:start position:0% +actually has this non-relativistic + + + align:start position:0% +actually has this non-relativistic +conformal symmetry + + align:start position:0% +conformal symmetry + + + align:start position:0% +conformal symmetry +if a goes to infinity + + align:start position:0% + + + + align:start position:0% + +so i'm not going to spend a lot of time + + align:start position:0% +so i'm not going to spend a lot of time + + + align:start position:0% +so i'm not going to spend a lot of time +talking about this + + align:start position:0% +talking about this + + + align:start position:0% +talking about this +but just to give you some of the ideas + + align:start position:0% +but just to give you some of the ideas + + + align:start position:0% +but just to give you some of the ideas +of what is going on + + align:start position:0% + + + + align:start position:0% + +if you look back last time at our + + align:start position:0% +if you look back last time at our + + + align:start position:0% +if you look back last time at our +solutions for this coupling constant and + + align:start position:0% +solutions for this coupling constant and + + + align:start position:0% +solutions for this coupling constant and +you take a goes to infinity + + align:start position:0% +you take a goes to infinity + + + align:start position:0% +you take a goes to infinity +that's a perfectly smooth limit you can + + align:start position:0% +that's a perfectly smooth limit you can + + + align:start position:0% +that's a perfectly smooth limit you can +do that + + align:start position:0% +do that + + + align:start position:0% +do that +and then the coupling c 0 of mu has no + + align:start position:0% +and then the coupling c 0 of mu has no + + + align:start position:0% +and then the coupling c 0 of mu has no +free parameters it's just given by 4 pi + + align:start position:0% +free parameters it's just given by 4 pi + + + align:start position:0% +free parameters it's just given by 4 pi +over mu + + align:start position:0% +over mu + + + align:start position:0% +over mu +and that's corresponds to sitting at + + align:start position:0% +and that's corresponds to sitting at + + + align:start position:0% +and that's corresponds to sitting at +this what i call what we last time saw + + align:start position:0% +this what i call what we last time saw + + + align:start position:0% +this what i call what we last time saw +was a fixed point of the beta function + + align:start position:0% +was a fixed point of the beta function + + + align:start position:0% +was a fixed point of the beta function +and at that fixed point there's enhanced + + align:start position:0% +and at that fixed point there's enhanced + + + align:start position:0% +and at that fixed point there's enhanced +symmetry which is this conformal + + align:start position:0% +symmetry which is this conformal + + + align:start position:0% +symmetry which is this conformal +symmetry + + align:start position:0% + + + + align:start position:0% + +and basically what you can show is that + + align:start position:0% +and basically what you can show is that + + + align:start position:0% +and basically what you can show is that +if you scale here mu + + align:start position:0% +if you scale here mu + + + align:start position:0% +if you scale here mu +just like it was a momentum + + align:start position:0% +just like it was a momentum + + + align:start position:0% +just like it was a momentum +so mu goes to e to the s mu + + align:start position:0% +so mu goes to e to the s mu + + + align:start position:0% +so mu goes to e to the s mu +then the lagrangian is scalar variant + + align:start position:0% +then the lagrangian is scalar variant + + + align:start position:0% +then the lagrangian is scalar variant +maybe in my notation up there would be + + align:start position:0% +maybe in my notation up there would be + + + align:start position:0% +maybe in my notation up there would be +minus s + + align:start position:0% + + + + align:start position:0% + +okay and that is basically kind of the + + align:start position:0% +okay and that is basically kind of the + + + align:start position:0% +okay and that is basically kind of the +same thing as making it into a relevant + + align:start position:0% +same thing as making it into a relevant + + + align:start position:0% +same thing as making it into a relevant +coupling once it's got no free + + align:start position:0% +coupling once it's got no free + + + align:start position:0% +coupling once it's got no free +parameters + + align:start position:0% +parameters + + + align:start position:0% +parameters +then + + align:start position:0% +then + + + align:start position:0% +then +you can sort of see that + + align:start position:0% +you can sort of see that + + + align:start position:0% +you can sort of see that +if i have a certain scaling that makes + + align:start position:0% +if i have a certain scaling that makes + + + align:start position:0% +if i have a certain scaling that makes +the free theory + + align:start position:0% +the free theory + + + align:start position:0% +the free theory +schroedinger invariant which is so the + + align:start position:0% +schroedinger invariant which is so the + + + align:start position:0% +schroedinger invariant which is so the +schrodinger group is the is the symmetry + + align:start position:0% +schrodinger group is the is the symmetry + + + align:start position:0% +schrodinger group is the is the symmetry +group of the free schrodinger equation + + align:start position:0% +group of the free schrodinger equation + + + align:start position:0% +group of the free schrodinger equation +so just this term in this term then the + + align:start position:0% +so just this term in this term then the + + + align:start position:0% +so just this term in this term then the +question is what interactions can you + + align:start position:0% +question is what interactions can you + + + align:start position:0% +question is what interactions can you +add that would preserve that symmetry + + align:start position:0% +add that would preserve that symmetry + + + align:start position:0% +add that would preserve that symmetry +and i'm just telling you that in terms + + align:start position:0% +and i'm just telling you that in terms + + + align:start position:0% +and i'm just telling you that in terms +of just the scale transformation + + align:start position:0% +of just the scale transformation + + + align:start position:0% +of just the scale transformation +you could if you're able to scale the + + align:start position:0% +you could if you're able to scale the + + + align:start position:0% +you could if you're able to scale the +coupling in some way in particular to + + align:start position:0% +coupling in some way in particular to + + + align:start position:0% +coupling in some way in particular to +make it a relevant interaction then that + + align:start position:0% +make it a relevant interaction then that + + + align:start position:0% +make it a relevant interaction then that +will make it a scale invariant theory + + align:start position:0% +will make it a scale invariant theory + + + align:start position:0% +will make it a scale invariant theory +and so the ability to scale this + + align:start position:0% +and so the ability to scale this + + + align:start position:0% +and so the ability to scale this +coupling because you scale this mu + + align:start position:0% +coupling because you scale this mu + + + align:start position:0% +coupling because you scale this mu +allows it to be a scale invariant theory + + align:start position:0% + + + + align:start position:0% + +it's a little harder to see that it's + + align:start position:0% +it's a little harder to see that it's + + + align:start position:0% +it's a little harder to see that it's +conformal but you can work that out too + + align:start position:0% + + + + align:start position:0% + +conform scale and variant theories tend + + align:start position:0% +conform scale and variant theories tend + + + align:start position:0% +conform scale and variant theories tend +to be conformally invariant and the same + + align:start position:0% +to be conformally invariant and the same + + + align:start position:0% +to be conformally invariant and the same +is true of this + + align:start position:0% +is true of this + + + align:start position:0% +is true of this +non-relativistic conformal invariance + + align:start position:0% + + + + align:start position:0% + +so if you sort of add up the bubbles + + align:start position:0% +so if you sort of add up the bubbles + + + align:start position:0% +so if you sort of add up the bubbles +that we were talking about + + align:start position:0% + + + + align:start position:0% + +then you find + + align:start position:0% +then you find + + + align:start position:0% +then you find +in general an amplitude + + align:start position:0% + + + + align:start position:0% + +which is this thing that has a square + + align:start position:0% +which is this thing that has a square + + + align:start position:0% +which is this thing that has a square +root + + align:start position:0% +root + + + align:start position:0% +root +but if i'm not particular to what frame + + align:start position:0% +but if i'm not particular to what frame + + + align:start position:0% +but if i'm not particular to what frame +i'm in now if i just write it for a + + align:start position:0% +i'm in now if i just write it for a + + + align:start position:0% +i'm in now if i just write it for a +general frame + + align:start position:0% +general frame + + + align:start position:0% +general frame +before we write it for the center of + + align:start position:0% +before we write it for the center of + + + align:start position:0% +before we write it for the center of +mass frame now let me write it for a + + align:start position:0% +mass frame now let me write it for a + + + align:start position:0% +mass frame now let me write it for a +general frame + + align:start position:0% + + + + align:start position:0% + +then it would look like this + + align:start position:0% + + + + align:start position:0% + +and that thing + + align:start position:0% +and that thing + + + align:start position:0% +and that thing +goes like one over p so it has and again + + align:start position:0% +goes like one over p so it has and again + + + align:start position:0% +goes like one over p so it has and again +e scale differently than ps + + align:start position:0% +e scale differently than ps + + + align:start position:0% +e scale differently than ps +so this thing has the right + + align:start position:0% +so this thing has the right + + + align:start position:0% +so this thing has the right +scaling for a scale invariant amplitude + + align:start position:0% + + + + align:start position:0% + +and it turns out if you do + + align:start position:0% +and it turns out if you do + + + align:start position:0% +and it turns out if you do +work out the conformal transformation + + align:start position:0% +work out the conformal transformation + + + align:start position:0% +work out the conformal transformation +it's also conformal invariant + + align:start position:0% +it's also conformal invariant + + + align:start position:0% +it's also conformal invariant +and i'm not going to go through that but + + align:start position:0% +and i'm not going to go through that but + + + align:start position:0% +and i'm not going to go through that but +i've posted a reference to show you how + + align:start position:0% +i've posted a reference to show you how + + + align:start position:0% +i've posted a reference to show you how +it works + + align:start position:0% +it works + + + align:start position:0% +it works +and basically what this leads to is a + + align:start position:0% +and basically what this leads to is a + + + align:start position:0% +and basically what this leads to is a +cross section + + align:start position:0% +cross section + + + align:start position:0% +cross section +which is four pi over p squared + + align:start position:0% +which is four pi over p squared + + + align:start position:0% +which is four pi over p squared +which is the scale and variant version + + align:start position:0% +which is the scale and variant version + + + align:start position:0% +which is the scale and variant version +of a cross section where the + + align:start position:0% +of a cross section where the + + + align:start position:0% +of a cross section where the +cross section units are just set by p so + + align:start position:0% +cross section units are just set by p so + + + align:start position:0% +cross section units are just set by p so +there's no other scale in the problem + + align:start position:0% +there's no other scale in the problem + + + align:start position:0% +there's no other scale in the problem +okay so that's kind of interesting and + + align:start position:0% +okay so that's kind of interesting and + + + align:start position:0% +okay so that's kind of interesting and +one can make some predictions with that + + align:start position:0% + + + + align:start position:0% + +this is actually something that's + + align:start position:0% +this is actually something that's + + + align:start position:0% +this is actually something that's +also you know investigated these days + + align:start position:0% +also you know investigated these days + + + align:start position:0% +also you know investigated these days +both from a string theory point of view + + align:start position:0% +both from a string theory point of view + + + align:start position:0% +both from a string theory point of view +as well as in cold atoms so the + + align:start position:0% +as well as in cold atoms so the + + + align:start position:0% +as well as in cold atoms so the +informal symmetries + + align:start position:0% +informal symmetries + + + align:start position:0% +informal symmetries +are always fun to play with + + align:start position:0% + + + + align:start position:0% + +there's also another set of symmetries + + align:start position:0% +there's also another set of symmetries + + + align:start position:0% +there's also another set of symmetries +that this theory has in this limit which + + align:start position:0% +that this theory has in this limit which + + + align:start position:0% +that this theory has in this limit which +is + + align:start position:0% +is + + + align:start position:0% +is +also interesting + + align:start position:0% + + + + align:start position:0% + +and that is like hqet there's an + + align:start position:0% +and that is like hqet there's an + + + align:start position:0% +and that is like hqet there's an +enhanced spin symmetry + + align:start position:0% + + + + align:start position:0% + +this this time the enhanced spin + + align:start position:0% +this this time the enhanced spin + + + align:start position:0% +this this time the enhanced spin +symmetry comes about by combining spin + + align:start position:0% +symmetry comes about by combining spin + + + align:start position:0% +symmetry comes about by combining spin +and isospin + + align:start position:0% + + + + align:start position:0% + +and this is a symmetry that's + + align:start position:0% +and this is a symmetry that's + + + align:start position:0% +and this is a symmetry that's +known as wigner's + + align:start position:0% +known as wigner's + + + align:start position:0% +known as wigner's +su4 symmetry + + align:start position:0% + + + + align:start position:0% + +so vigner + + align:start position:0% +so vigner + + + align:start position:0% +so vigner +i don't know how many years ago + + align:start position:0% +i don't know how many years ago + + + align:start position:0% +i don't know how many years ago +noticed long long ago vigner noticed + + align:start position:0% +noticed long long ago vigner noticed + + + align:start position:0% +noticed long long ago vigner noticed +that + + align:start position:0% +that + + + align:start position:0% +that +nuclei tend to have a symmetry which is + + align:start position:0% +nuclei tend to have a symmetry which is + + + align:start position:0% +nuclei tend to have a symmetry which is +a combination of spin and isospin into a + + align:start position:0% +a combination of spin and isospin into a + + + align:start position:0% +a combination of spin and isospin into a +full su4 + + align:start position:0% +full su4 + + + align:start position:0% +full su4 +and we can understand actually partly + + align:start position:0% +and we can understand actually partly + + + align:start position:0% +and we can understand actually partly +where that comes from from this + + align:start position:0% +where that comes from from this + + + align:start position:0% +where that comes from from this +effective field theory + + align:start position:0% +effective field theory + + + align:start position:0% +effective field theory +so what is this su 4 + + align:start position:0% +so what is this su 4 + + + align:start position:0% +so what is this su 4 +think of it as just transforming the + + align:start position:0% +think of it as just transforming the + + + align:start position:0% +think of it as just transforming the +nucleon field + + align:start position:0% + + + + align:start position:0% + +under a way where you could mix up the + + align:start position:0% +under a way where you could mix up the + + + align:start position:0% +under a way where you could mix up the +spin in the isospin so if sigma is for + + align:start position:0% +spin in the isospin so if sigma is for + + + align:start position:0% +spin in the isospin so if sigma is for +the spin tau is for the isospin + + align:start position:0% +the spin tau is for the isospin + + + align:start position:0% +the spin tau is for the isospin +then some combined transformation where + + align:start position:0% +then some combined transformation where + + + align:start position:0% +then some combined transformation where +i can mix up the mu and news we just + + align:start position:0% +i can mix up the mu and news we just + + + align:start position:0% +i can mix up the mu and news we just +have some set of generators where i + + align:start position:0% +have some set of generators where i + + + align:start position:0% +have some set of generators where i +label them by mu and nu + + align:start position:0% +label them by mu and nu + + + align:start position:0% +label them by mu and nu +sigma mu here is one comma sigma vector + + align:start position:0% +sigma mu here is one comma sigma vector + + + align:start position:0% +sigma mu here is one comma sigma vector +tau nu + + align:start position:0% +tau nu + + + align:start position:0% +tau nu +one comma tau vector for the isospin + + align:start position:0% + + + + align:start position:0% + +if you just take the one from both of + + align:start position:0% +if you just take the one from both of + + + align:start position:0% +if you just take the one from both of +them that's baryon number and that is + + align:start position:0% +them that's baryon number and that is + + + align:start position:0% +them that's baryon number and that is +you know what return the se4 into a u + + align:start position:0% +you know what return the se4 into a u + + + align:start position:0% +you know what return the se4 into a u +floor so + + align:start position:0% +floor so + + + align:start position:0% +floor so +you can remove that generator if you + + align:start position:0% +you can remove that generator if you + + + align:start position:0% +you can remove that generator if you +like + + align:start position:0% +like + + + align:start position:0% +like +so there's a u1 as well but the + + align:start position:0% +so there's a u1 as well but the + + + align:start position:0% +so there's a u1 as well but the +non-trivial part where you take either + + align:start position:0% +non-trivial part where you take either + + + align:start position:0% +non-trivial part where you take either +this or that or both is an su4 + + align:start position:0% + + + + align:start position:0% + +so we can think about this symmetry with + + align:start position:0% +so we can think about this symmetry with + + + align:start position:0% +so we can think about this symmetry with +our theory if we write it as follows so + + align:start position:0% +our theory if we write it as follows so + + + align:start position:0% +our theory if we write it as follows so +take the interaction terms that we've + + align:start position:0% +take the interaction terms that we've + + + align:start position:0% +take the interaction terms that we've +been talking about + + align:start position:0% +been talking about + + + align:start position:0% +been talking about +and write them in a slightly different + + align:start position:0% +and write them in a slightly different + + + align:start position:0% +and write them in a slightly different +basis + + align:start position:0% + + + + align:start position:0% + +just take these + + align:start position:0% +just take these + + + align:start position:0% +just take these +two to two scattering + + align:start position:0% +two to two scattering + + + align:start position:0% +two to two scattering +terms which note with had no no + + align:start position:0% +terms which note with had no no + + + align:start position:0% +terms which note with had no no +derivatives + + align:start position:0% +derivatives + + + align:start position:0% +derivatives +and i'll write them in a slightly + + align:start position:0% +and i'll write them in a slightly + + + align:start position:0% +and i'll write them in a slightly +different basis + + align:start position:0% +different basis + + + align:start position:0% +different basis +before we wrote them in sort of the + + align:start position:0% +before we wrote them in sort of the + + + align:start position:0% +before we wrote them in sort of the +physical basis where we had 3s1 and 1s0 + + align:start position:0% +physical basis where we had 3s1 and 1s0 + + + align:start position:0% +physical basis where we had 3s1 and 1s0 +that's what we did last time + + align:start position:0% +that's what we did last time + + + align:start position:0% +that's what we did last time +but there's other possible bases and i + + align:start position:0% +but there's other possible bases and i + + + align:start position:0% +but there's other possible bases and i +can write them in this basis + + align:start position:0% +can write them in this basis + + + align:start position:0% +can write them in this basis +triplet basis + + align:start position:0% +triplet basis + + + align:start position:0% +triplet basis +and the advantage of this basis is this + + align:start position:0% +and the advantage of this basis is this + + + align:start position:0% +and the advantage of this basis is this +thing here is just super symmetric + + align:start position:0% + + + + align:start position:0% + +and if you want to write down the + + align:start position:0% +and if you want to write down the + + + align:start position:0% +and if you want to write down the +relation to the previous basis + + align:start position:0% +relation to the previous basis + + + align:start position:0% +relation to the previous basis +you can work that out + + align:start position:0% +you can work that out + + + align:start position:0% +you can work that out +and just tell you what it would be + + align:start position:0% +and just tell you what it would be + + + align:start position:0% +and just tell you what it would be +by writing down what the coefficients + + align:start position:0% +by writing down what the coefficients + + + align:start position:0% +by writing down what the coefficients +here are in terms of the ones we had + + align:start position:0% +here are in terms of the ones we had + + + align:start position:0% +here are in terms of the ones we had +before + + align:start position:0% + + + + align:start position:0% + +so if we go back to the basis where we + + align:start position:0% +so if we go back to the basis where we + + + align:start position:0% +so if we go back to the basis where we +had coefficients for the 3s1 channel on + + align:start position:0% +had coefficients for the 3s1 channel on + + + align:start position:0% +had coefficients for the 3s1 channel on +the 1s0 channel + + align:start position:0% +the 1s0 channel + + + align:start position:0% +the 1s0 channel +then this c0s becomes this combination + + align:start position:0% +then this c0s becomes this combination + + + align:start position:0% +then this c0s becomes this combination +and c0t is this combination + + align:start position:0% + + + + align:start position:0% + +now in nature + + align:start position:0% +now in nature + + + align:start position:0% +now in nature +so one way you could have su4 symmetry + + align:start position:0% +so one way you could have su4 symmetry + + + align:start position:0% +so one way you could have su4 symmetry +would just be for the scattering lengths + + align:start position:0% +would just be for the scattering lengths + + + align:start position:0% +would just be for the scattering lengths +the physical parameters c01s + + align:start position:0% +the physical parameters c01s + + + align:start position:0% +the physical parameters c01s +0 and c03s1 to be equal + + align:start position:0% +0 and c03s1 to be equal + + + align:start position:0% +0 and c03s1 to be equal +but in nature they're not equal at all + + align:start position:0% +but in nature they're not equal at all + + + align:start position:0% +but in nature they're not equal at all +they in fact the scattering links have + + align:start position:0% +they in fact the scattering links have + + + align:start position:0% +they in fact the scattering links have +different signs there's no + + align:start position:0% +different signs there's no + + + align:start position:0% +different signs there's no +sense in which they're equal + + align:start position:0% +sense in which they're equal + + + align:start position:0% +sense in which they're equal +so what is the sense in which we have + + align:start position:0% +so what is the sense in which we have + + + align:start position:0% +so what is the sense in which we have +this symmetry + + align:start position:0% +this symmetry + + + align:start position:0% +this symmetry +the sense in which we have this symmetry + + align:start position:0% +the sense in which we have this symmetry + + + align:start position:0% +the sense in which we have this symmetry +is the fact that if + + align:start position:0% +is the fact that if + + + align:start position:0% +is the fact that if +the scattering lengths are both infinity + + align:start position:0% +the scattering lengths are both infinity + + + align:start position:0% +the scattering lengths are both infinity +then both couplings are just this + + align:start position:0% +then both couplings are just this + + + align:start position:0% +then both couplings are just this +so the fact that the scattering lengths + + align:start position:0% +so the fact that the scattering lengths + + + align:start position:0% +so the fact that the scattering lengths +are + + align:start position:0% +are + + + align:start position:0% +are +have different signs but are both large + + align:start position:0% +have different signs but are both large + + + align:start position:0% +have different signs but are both large +makes them close to this fixed point + + align:start position:0% +makes them close to this fixed point + + + align:start position:0% +makes them close to this fixed point +which then gives us symmetry + + align:start position:0% + + + + align:start position:0% + +okay so because of what i just said + + align:start position:0% + + + + align:start position:0% + +for a goes to infinity + + align:start position:0% +for a goes to infinity + + + align:start position:0% +for a goes to infinity +c0s which is sort of equal + + align:start position:0% +c0s which is sort of equal + + + align:start position:0% +c0s which is sort of equal +some symmetric combination of these two + + align:start position:0% +some symmetric combination of these two + + + align:start position:0% +some symmetric combination of these two +that become equal + + align:start position:0% +that become equal + + + align:start position:0% +that become equal +would just become + + align:start position:0% +would just become + + + align:start position:0% +would just become +4 pi over mu + + align:start position:0% +4 pi over mu + + + align:start position:0% +4 pi over mu +and this is for a1 s0 and a 3 s 1 + + align:start position:0% +and this is for a1 s0 and a 3 s 1 + + + align:start position:0% +and this is for a1 s0 and a 3 s 1 +both going to infinity this one's minus + + align:start position:0% +both going to infinity this one's minus + + + align:start position:0% +both going to infinity this one's minus +infinity + + align:start position:0% + + + + align:start position:0% + +and then the triplet 1 if we just work + + align:start position:0% +and then the triplet 1 if we just work + + + align:start position:0% +and then the triplet 1 if we just work +out what it is from our formulas for + + align:start position:0% +out what it is from our formulas for + + + align:start position:0% +out what it is from our formulas for +those other couplings + + align:start position:0% + + + + align:start position:0% + +and just + + align:start position:0% +and just + + + align:start position:0% +and just +work out the combination from formulas + + align:start position:0% +work out the combination from formulas + + + align:start position:0% +work out the combination from formulas +we had last time + + align:start position:0% +we had last time + + + align:start position:0% +we had last time +and we see that as the a's go to + + align:start position:0% +and we see that as the a's go to + + + align:start position:0% +and we see that as the a's go to +infinity this coupling vanishes + + align:start position:0% + + + + align:start position:0% + +okay so + + align:start position:0% +okay so + + + align:start position:0% +okay so +when we're in the limit where both of + + align:start position:0% +when we're in the limit where both of + + + align:start position:0% +when we're in the limit where both of +the couplings become equal or if we use + + align:start position:0% +the couplings become equal or if we use + + + align:start position:0% +the couplings become equal or if we use +this basis where this coupling becomes + + align:start position:0% +this basis where this coupling becomes + + + align:start position:0% +this basis where this coupling becomes +zero we just have this + + align:start position:0% +zero we just have this + + + align:start position:0% +zero we just have this +n dagger n squared operator then we have + + align:start position:0% +n dagger n squared operator then we have + + + align:start position:0% +n dagger n squared operator then we have +this su4 symmetry + + align:start position:0% + + + + align:start position:0% + +on your on one of the problems on this + + align:start position:0% +on your on one of the problems on this + + + align:start position:0% +on your on one of the problems on this +new problem set is to think about what + + align:start position:0% +new problem set is to think about what + + + align:start position:0% +new problem set is to think about what +how much to what degree you still have + + align:start position:0% +how much to what degree you still have + + + align:start position:0% +how much to what degree you still have +that symmetry when you think about + + align:start position:0% +that symmetry when you think about + + + align:start position:0% +that symmetry when you think about +higher body operators three body and + + align:start position:0% +higher body operators three body and + + + align:start position:0% +higher body operators three body and +forebody + + align:start position:0% +forebody + + + align:start position:0% +forebody +and there's actually some very nice + + align:start position:0% +and there's actually some very nice + + + align:start position:0% +and there's actually some very nice +little group theory arguments where you + + align:start position:0% +little group theory arguments where you + + + align:start position:0% +little group theory arguments where you +can basically figure out how what to + + align:start position:0% +can basically figure out how what to + + + align:start position:0% +can basically figure out how what to +what degree you have that symmetry + + align:start position:0% +what degree you have that symmetry + + + align:start position:0% +what degree you have that symmetry +in the higher body operators + + align:start position:0% + + + + align:start position:0% + +it turns out that it's also present + + align:start position:0% +it turns out that it's also present + + + align:start position:0% +it turns out that it's also present +there + + align:start position:0% + + + + align:start position:0% + +and that + + align:start position:0% +and that + + + align:start position:0% +and that +is one way of thinking about why + + align:start position:0% +is one way of thinking about why + + + align:start position:0% +is one way of thinking about why +vigner's symmetries exist in nature it's + + align:start position:0% +vigner's symmetries exist in nature it's + + + align:start position:0% +vigner's symmetries exist in nature it's +not that we're + + align:start position:0% +not that we're + + + align:start position:0% +not that we're +in any sense having scattering lengths + + align:start position:0% +in any sense having scattering lengths + + + align:start position:0% +in any sense having scattering lengths +that are similar in this these two + + align:start position:0% +that are similar in this these two + + + align:start position:0% +that are similar in this these two +channels but since they're both large + + align:start position:0% +channels but since they're both large + + + align:start position:0% +channels but since they're both large +we're close to the same we're close to + + align:start position:0% +we're close to the same we're close to + + + align:start position:0% +we're close to the same we're close to +these fixed points + + align:start position:0% +these fixed points + + + align:start position:0% +these fixed points +which have this symmetry + + align:start position:0% +which have this symmetry + + + align:start position:0% +which have this symmetry +okay so it's like hqet in a sense where + + align:start position:0% +okay so it's like hqet in a sense where + + + align:start position:0% +okay so it's like hqet in a sense where +we didn't have heavy cork spin symmetry + + align:start position:0% +we didn't have heavy cork spin symmetry + + + align:start position:0% +we didn't have heavy cork spin symmetry +when the masses are finite but if the + + align:start position:0% +when the masses are finite but if the + + + align:start position:0% +when the masses are finite but if the +charm mass and the b mass are both + + align:start position:0% +charm mass and the b mass are both + + + align:start position:0% +charm mass and the b mass are both +infinite then there's this new symmetry + + align:start position:0% +infinite then there's this new symmetry + + + align:start position:0% +infinite then there's this new symmetry +that pops up + + align:start position:0% +that pops up + + + align:start position:0% +that pops up +it's kind of like that + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +all right so rather than talk about the + + align:start position:0% +all right so rather than talk about the + + + align:start position:0% +all right so rather than talk about the +symmetries in any more detail than that + + align:start position:0% +symmetries in any more detail than that + + + align:start position:0% +symmetries in any more detail than that +what i wanted to do is actually do + + align:start position:0% +what i wanted to do is actually do + + + align:start position:0% +what i wanted to do is actually do +something a little different with this + + align:start position:0% +something a little different with this + + + align:start position:0% +something a little different with this +theory so there's lots of things we + + align:start position:0% +theory so there's lots of things we + + + align:start position:0% +theory so there's lots of things we +could discuss here + + align:start position:0% +could discuss here + + + align:start position:0% +could discuss here +but the thing i want to discuss is + + align:start position:0% +but the thing i want to discuss is + + + align:start position:0% +but the thing i want to discuss is +actually + + align:start position:0% +actually + + + align:start position:0% +actually +treating a bound state + + align:start position:0% +treating a bound state + + + align:start position:0% +treating a bound state +in the in a field theory + + align:start position:0% +in the in a field theory + + + align:start position:0% +in the in a field theory +this field theory has + + align:start position:0% +this field theory has + + + align:start position:0% +this field theory has +a very nice property that we can + + align:start position:0% +a very nice property that we can + + + align:start position:0% +a very nice property that we can +calculate everything + + align:start position:0% +calculate everything + + + align:start position:0% +calculate everything +so we can actually see how you're + + align:start position:0% +so we can actually see how you're + + + align:start position:0% +so we can actually see how you're +supposed to treat bound states + + align:start position:0% +supposed to treat bound states + + + align:start position:0% +supposed to treat bound states +exactly because we can actually just + + align:start position:0% +exactly because we can actually just + + + align:start position:0% +exactly because we can actually just +look for the pole that corresponds to + + align:start position:0% +look for the pole that corresponds to + + + align:start position:0% +look for the pole that corresponds to +that bounce state in this theory that's + + align:start position:0% +that bounce state in this theory that's + + + align:start position:0% +that bounce state in this theory that's +what we're going to do + + align:start position:0% + + + + align:start position:0% + +so usually if you have a bound state + + align:start position:0% +so usually if you have a bound state + + + align:start position:0% +so usually if you have a bound state +it's either + + align:start position:0% +it's either + + + align:start position:0% +it's either +something that's non non-perturbative + + align:start position:0% +something that's non non-perturbative + + + align:start position:0% +something that's non non-perturbative +that you have trouble dealing with + + align:start position:0% +that you have trouble dealing with + + + align:start position:0% +that you have trouble dealing with +analytically like in qcd + + align:start position:0% +analytically like in qcd + + + align:start position:0% +analytically like in qcd +or coulombic even then the calculations + + align:start position:0% +or coulombic even then the calculations + + + align:start position:0% +or coulombic even then the calculations +get kind of hairy although you can deal + + align:start position:0% +get kind of hairy although you can deal + + + align:start position:0% +get kind of hairy although you can deal +with it there + + align:start position:0% +with it there + + + align:start position:0% +with it there +but here the calculations are very + + align:start position:0% +but here the calculations are very + + + align:start position:0% +but here the calculations are very +simple so we can really follow all the + + align:start position:0% +simple so we can really follow all the + + + align:start position:0% +simple so we can really follow all the +steps of properly dealing with the bound + + align:start position:0% +steps of properly dealing with the bound + + + align:start position:0% +steps of properly dealing with the bound +state + + align:start position:0% + + + + align:start position:0% + +and the bound state has something to do + + align:start position:0% +and the bound state has something to do + + + align:start position:0% +and the bound state has something to do +with nature it's a stated nature called + + align:start position:0% +with nature it's a stated nature called + + + align:start position:0% +with nature it's a stated nature called +the deuteron + + align:start position:0% + + + + align:start position:0% + +so the deuteron is a balanced need of a + + align:start position:0% +so the deuteron is a balanced need of a + + + align:start position:0% +so the deuteron is a balanced need of a +neutron and a proton + + align:start position:0% + + + + align:start position:0% + +it has isospin zero + + align:start position:0% +it has isospin zero + + + align:start position:0% +it has isospin zero +spin one + + align:start position:0% +spin one + + + align:start position:0% +spin one +so it's in this 3s1 state that we talked + + align:start position:0% +so it's in this 3s1 state that we talked + + + align:start position:0% +so it's in this 3s1 state that we talked +about + + align:start position:0% + + + + align:start position:0% + +and when you want to look for a bounce + + align:start position:0% +and when you want to look for a bounce + + + align:start position:0% +and when you want to look for a bounce +state in field theory what you do + + align:start position:0% +state in field theory what you do + + + align:start position:0% +state in field theory what you do +if you you may have heard of this from + + align:start position:0% +if you you may have heard of this from + + + align:start position:0% +if you you may have heard of this from +the lattice point of view what you do is + + align:start position:0% +the lattice point of view what you do is + + + align:start position:0% +the lattice point of view what you do is +you write down some interpolating field + + align:start position:0% +you write down some interpolating field + + + align:start position:0% +you write down some interpolating field +that has overlap + + align:start position:0% +that has overlap + + + align:start position:0% +that has overlap +with that state + + align:start position:0% + + + + align:start position:0% + +so what would that be for us + + align:start position:0% +so what would that be for us + + + align:start position:0% +so what would that be for us +that would be + + align:start position:0% +that would be + + + align:start position:0% +that would be +this operator that we called + + align:start position:0% +this operator that we called + + + align:start position:0% +this operator that we called +pi3s1 which had the quantum numbers for + + align:start position:0% +pi3s1 which had the quantum numbers for + + + align:start position:0% +pi3s1 which had the quantum numbers for +i equals 0 and s equals 1. + + align:start position:0% +i equals 0 and s equals 1. + + + align:start position:0% +i equals 0 and s equals 1. +and we can build an interpolating field + + align:start position:0% +and we can build an interpolating field + + + align:start position:0% +and we can build an interpolating field +out of our n transpose n and actually + + align:start position:0% +out of our n transpose n and actually + + + align:start position:0% +out of our n transpose n and actually +any interpolating field that we write + + align:start position:0% +any interpolating field that we write + + + align:start position:0% +any interpolating field that we write +down here is equally good + + align:start position:0% +down here is equally good + + + align:start position:0% +down here is equally good +a lot of qcd people like to tune what + + align:start position:0% +a lot of qcd people like to tune what + + + align:start position:0% +a lot of qcd people like to tune what +they write down + + align:start position:0% +they write down + + + align:start position:0% +they write down +in order to improve the overlap with the + + align:start position:0% +in order to improve the overlap with the + + + align:start position:0% +in order to improve the overlap with the +state + + align:start position:0% +state + + + align:start position:0% +state +but for our purposes the simplest + + align:start position:0% +but for our purposes the simplest + + + align:start position:0% +but for our purposes the simplest +possible thing will be enough + + align:start position:0% +possible thing will be enough + + + align:start position:0% +possible thing will be enough +and then you can ask the question is the + + align:start position:0% +and then you can ask the question is the + + + align:start position:0% +and then you can ask the question is the +deuteron in the theory + + align:start position:0% + + + + align:start position:0% + +and to answer that question you can just + + align:start position:0% +and to answer that question you can just + + + align:start position:0% +and to answer that question you can just +look for the poll that would correspond + + align:start position:0% +look for the poll that would correspond + + + align:start position:0% +look for the poll that would correspond +to that state + + align:start position:0% +to that state + + + align:start position:0% +to that state +and the advantage of this theory is that + + align:start position:0% +and the advantage of this theory is that + + + align:start position:0% +and the advantage of this theory is that +we can just look for that poll + + align:start position:0% +we can just look for that poll + + + align:start position:0% +we can just look for that poll +analytically + + align:start position:0% + + + + align:start position:0% + +so let's do that + + align:start position:0% + + + + align:start position:0% + +so i'll write down a greens function + + align:start position:0% +so i'll write down a greens function + + + align:start position:0% +so i'll write down a greens function +for the two particle state + + align:start position:0% + + + + align:start position:0% + +which is just the time order product of + + align:start position:0% +which is just the time order product of + + + align:start position:0% +which is just the time order product of +two of these interplaying fields + + align:start position:0% + + + + align:start position:0% + +and then ask the question if i look at + + align:start position:0% +and then ask the question if i look at + + + align:start position:0% +and then ask the question if i look at +that thai water product is there a pole + + align:start position:0% +that thai water product is there a pole + + + align:start position:0% +that thai water product is there a pole +that would correspond to this state + + align:start position:0% +that would correspond to this state + + + align:start position:0% +that would correspond to this state +i somewhere is there a pole + + align:start position:0% +i somewhere is there a pole + + + align:start position:0% +i somewhere is there a pole +which would behave as follows + + align:start position:0% +which would behave as follows + + + align:start position:0% +which would behave as follows +some kind of z + + align:start position:0% +some kind of z + + + align:start position:0% +some kind of z +factor and then + + align:start position:0% + + + + align:start position:0% + +in this case because of our + + align:start position:0% + + + + align:start position:0% + +because of the way we've scaled energies + + align:start position:0% +because of the way we've scaled energies + + + align:start position:0% +because of the way we've scaled energies +we would just be looking for a pole + + align:start position:0% +we would just be looking for a pole + + + align:start position:0% +we would just be looking for a pole +that's linear in the energy at some + + align:start position:0% +that's linear in the energy at some + + + align:start position:0% +that's linear in the energy at some +negative energy corresponding to the + + align:start position:0% +negative energy corresponding to the + + + align:start position:0% +negative energy corresponding to the +binding energy of that state + + align:start position:0% +binding energy of that state + + + align:start position:0% +binding energy of that state +so remember that we pulled out the mass + + align:start position:0% +so remember that we pulled out the mass + + + align:start position:0% +so remember that we pulled out the mass +of the nucleon that wasn't in our + + align:start position:0% +of the nucleon that wasn't in our + + + align:start position:0% +of the nucleon that wasn't in our +lagrangian so + + align:start position:0% +lagrangian so + + + align:start position:0% +lagrangian so +really the the if you think about what + + align:start position:0% +really the the if you think about what + + + align:start position:0% +really the the if you think about what +the + + align:start position:0% +the + + + align:start position:0% +the +the mass the sort of energy of this + + align:start position:0% +the mass the sort of energy of this + + + align:start position:0% +the mass the sort of energy of this +state is it's two nucleons so it's got + + align:start position:0% +state is it's two nucleons so it's got + + + align:start position:0% +state is it's two nucleons so it's got +the + + align:start position:0% +the + + + align:start position:0% +the +energy of those two nucleons but then + + align:start position:0% +energy of those two nucleons but then + + + align:start position:0% +energy of those two nucleons but then +there's a little bit less because it's a + + align:start position:0% +there's a little bit less because it's a + + + align:start position:0% +there's a little bit less because it's a +bound state + + align:start position:0% +bound state + + + align:start position:0% +bound state +and this is the amount by + + align:start position:0% +and this is the amount by + + + align:start position:0% +and this is the amount by +how much less + + align:start position:0% +how much less + + + align:start position:0% +how much less +and so the energy for the pole is + + align:start position:0% +and so the energy for the pole is + + + align:start position:0% +and so the energy for the pole is +negative e bar is less than zero because + + align:start position:0% +negative e bar is less than zero because + + + align:start position:0% +negative e bar is less than zero because +it's how much less than the two nucleon + + align:start position:0% +it's how much less than the two nucleon + + + align:start position:0% +it's how much less than the two nucleon +mass + + align:start position:0% + + + + align:start position:0% + +so this e bar is the + + align:start position:0% + + + + align:start position:0% + +two nucleon center of mass energy + + align:start position:0% + + + + align:start position:0% + +which + + align:start position:0% +which + + + align:start position:0% +which +in the conventions we were using last + + align:start position:0% +in the conventions we were using last + + + align:start position:0% +in the conventions we were using last +time is + + align:start position:0% + + + + align:start position:0% + +we had e + + align:start position:0% +we had e + + + align:start position:0% +we had e +energy e over 2 for each of the nucleons + + align:start position:0% +energy e over 2 for each of the nucleons + + + align:start position:0% +energy e over 2 for each of the nucleons +so the sum would be e + + align:start position:0% +so the sum would be e + + + align:start position:0% +so the sum would be e +there's some kinetic term as well + + align:start position:0% + + + + align:start position:0% + +so what are the diagrams that we would + + align:start position:0% +so what are the diagrams that we would + + + align:start position:0% +so what are the diagrams that we would +consider to do this + + align:start position:0% +consider to do this + + + align:start position:0% +consider to do this +well at lowest order it's just our + + align:start position:0% +well at lowest order it's just our + + + align:start position:0% +well at lowest order it's just our +friends the bubble sum + + align:start position:0% +friends the bubble sum + + + align:start position:0% +friends the bubble sum +and in fact when you go to higher orders + + align:start position:0% +and in fact when you go to higher orders + + + align:start position:0% +and in fact when you go to higher orders +there's also we also had bubbles there + + align:start position:0% +there's also we also had bubbles there + + + align:start position:0% +there's also we also had bubbles there +so + + align:start position:0% +so + + + align:start position:0% +so +to add to this question we insert the + + align:start position:0% +to add to this question we insert the + + + align:start position:0% +to add to this question we insert the +field we create two nucleons and then + + align:start position:0% +field we create two nucleons and then + + + align:start position:0% +field we create two nucleons and then +they can interact with c zeros + + align:start position:0% +they can interact with c zeros + + + align:start position:0% +they can interact with c zeros +and then we annihilate them with our + + align:start position:0% +and then we annihilate them with our + + + align:start position:0% +and then we annihilate them with our +interplaying field + + align:start position:0% +interplaying field + + + align:start position:0% +interplaying field +so these are just our c0 bubbles + + align:start position:0% + + + + align:start position:0% + +okay and those are very easy to compute + + align:start position:0% + + + + align:start position:0% + +it's just the geometric series that we + + align:start position:0% +it's just the geometric series that we + + + align:start position:0% +it's just the geometric series that we +already computed + + align:start position:0% +already computed + + + align:start position:0% +already computed +and instead of having two nucleons in + + align:start position:0% +and instead of having two nucleons in + + + align:start position:0% +and instead of having two nucleons in +two nucleons out we just have this + + align:start position:0% +two nucleons out we just have this + + + align:start position:0% +two nucleons out we just have this +deuteron state in deuteronomy state out + + align:start position:0% + + + + align:start position:0% + +okay so the greens function + + align:start position:0% +okay so the greens function + + + align:start position:0% +okay so the greens function +starts with one of these + + align:start position:0% +starts with one of these + + + align:start position:0% +starts with one of these +and then just + + align:start position:0% +and then just + + + align:start position:0% +and then just +iterates into a + + align:start position:0% +iterates into a + + + align:start position:0% +iterates into a +iterates into a geometric series + + align:start position:0% +iterates into a geometric series + + + align:start position:0% +iterates into a geometric series +where sigma i could define as + + align:start position:0% +where sigma i could define as + + + align:start position:0% +where sigma i could define as +two particle irreducible c0 graphs so + + align:start position:0% +two particle irreducible c0 graphs so + + + align:start position:0% +two particle irreducible c0 graphs so +sort of + + align:start position:0% +sort of + + + align:start position:0% +sort of +taking out the c0 iterations + + align:start position:0% +taking out the c0 iterations + + + align:start position:0% +taking out the c0 iterations +so the sigma 1 that i'm talking about + + align:start position:0% +so the sigma 1 that i'm talking about + + + align:start position:0% +so the sigma 1 that i'm talking about +here + + align:start position:0% +here + + + align:start position:0% +here +is just this bubble all by itself + + align:start position:0% + + + + align:start position:0% + +and that's something that we computed + + align:start position:0% +and that's something that we computed + + + align:start position:0% +and that's something that we computed +before + + align:start position:0% + + + + align:start position:0% + +and then these + + align:start position:0% +and then these + + + align:start position:0% +and then these +normalization schemes that we like + + align:start position:0% + + + + align:start position:0% + +just comes out to be this + + align:start position:0% + + + + align:start position:0% + +so there's an m out front and nucleon + + align:start position:0% +so there's an m out front and nucleon + + + align:start position:0% +so there's an m out front and nucleon +it's not an it's an m not a mu + + align:start position:0% +it's not an it's an m not a mu + + + align:start position:0% +it's not an it's an m not a mu +and then in terms of this e bar it just + + align:start position:0% +and then in terms of this e bar it just + + + align:start position:0% +and then in terms of this e bar it just +comes out through that + + align:start position:0% + + + + align:start position:0% + +so you could think of making a positive + + align:start position:0% +so you could think of making a positive + + + align:start position:0% +so you could think of making a positive +energy by taking e bar to be minus e + + align:start position:0% +energy by taking e bar to be minus e + + + align:start position:0% +energy by taking e bar to be minus e +bound + + align:start position:0% +bound + + + align:start position:0% +bound +which is less than zero + + align:start position:0% +which is less than zero + + + align:start position:0% +which is less than zero +and then the square root would be square + + align:start position:0% +and then the square root would be square + + + align:start position:0% +and then the square root would be square +root of m + + align:start position:0% +root of m + + + align:start position:0% +root of m +e b + + align:start position:0% + + + + align:start position:0% + +and it's convenient to define that to be + + align:start position:0% +and it's convenient to define that to be + + + align:start position:0% +and it's convenient to define that to be +something + + align:start position:0% +something + + + align:start position:0% +something +so i'll call it gamma b + + align:start position:0% +so i'll call it gamma b + + + align:start position:0% +so i'll call it gamma b +so that's some quantity greater than + + align:start position:0% +so that's some quantity greater than + + + align:start position:0% +so that's some quantity greater than +zero + + align:start position:0% +zero + + + align:start position:0% +zero +and with this little notation this + + align:start position:0% +and with this little notation this + + + align:start position:0% +and with this little notation this +square root + + align:start position:0% +square root + + + align:start position:0% +square root +of minus m e bar + + align:start position:0% +of minus m e bar + + + align:start position:0% +of minus m e bar +minus i0 + + align:start position:0% + + + + align:start position:0% + +is equal to minus ip + + align:start position:0% +is equal to minus ip + + + align:start position:0% +is equal to minus ip +and we're looking for whether that + + align:start position:0% + + + + align:start position:0% + +would be sort of + + align:start position:0% +would be sort of + + + align:start position:0% +would be sort of +going over to this gamma b + + align:start position:0% +going over to this gamma b + + + align:start position:0% +going over to this gamma b +sorry so this is equal to gamma b + + align:start position:0% + + + + align:start position:0% + +so gamma b is just like a momentum + + align:start position:0% +so gamma b is just like a momentum + + + align:start position:0% +so gamma b is just like a momentum +version of the bound state energy + + align:start position:0% +version of the bound state energy + + + align:start position:0% +version of the bound state energy +absorbing the extra eye + + align:start position:0% + + + + align:start position:0% + +okay this is what it would have been + + align:start position:0% +okay this is what it would have been + + + align:start position:0% +okay this is what it would have been +previously but now it's gamma b + + align:start position:0% + + + + align:start position:0% + +so we know what g was we already + + align:start position:0% +so we know what g was we already + + + align:start position:0% +so we know what g was we already +computed it earlier g + + align:start position:0% +computed it earlier g + + + align:start position:0% +computed it earlier g +was just proportional to 1 over a + + align:start position:0% +was just proportional to 1 over a + + + align:start position:0% +was just proportional to 1 over a +plus i p + + align:start position:0% +plus i p + + + align:start position:0% +plus i p +and now if i just make that replacement + + align:start position:0% +and now if i just make that replacement + + + align:start position:0% +and now if i just make that replacement +which is why i wanted to derive that + + align:start position:0% +which is why i wanted to derive that + + + align:start position:0% +which is why i wanted to derive that +because i wanted to just see how i would + + align:start position:0% +because i wanted to just see how i would + + + align:start position:0% +because i wanted to just see how i would +replace the ip + + align:start position:0% +replace the ip + + + align:start position:0% +replace the ip +becomes 1 over a minus gamma b so gamma + + align:start position:0% +becomes 1 over a minus gamma b so gamma + + + align:start position:0% +becomes 1 over a minus gamma b so gamma +b is a kinematic variable it's like a + + align:start position:0% +b is a kinematic variable it's like a + + + align:start position:0% +b is a kinematic variable it's like a +momentum + + align:start position:0% +momentum + + + align:start position:0% +momentum +but it's the right kinematic variable to + + align:start position:0% +but it's the right kinematic variable to + + + align:start position:0% +but it's the right kinematic variable to +be talking about for the bound state + + align:start position:0% +be talking about for the bound state + + + align:start position:0% +be talking about for the bound state +it's a positive thing + + align:start position:0% +it's a positive thing + + + align:start position:0% +it's a positive thing +and you can see there's a pole + + align:start position:0% + + + + align:start position:0% + +okay so there's the pole corresponding + + align:start position:0% +okay so there's the pole corresponding + + + align:start position:0% +okay so there's the pole corresponding +to the deer around state it just + + align:start position:0% +to the deer around state it just + + + align:start position:0% +to the deer around state it just +corresponds to gamma equals 1 over + + align:start position:0% +corresponds to gamma equals 1 over + + + align:start position:0% +corresponds to gamma equals 1 over +a of the 3s1 + + align:start position:0% + + + + align:start position:0% + +which in nature is like + + align:start position:0% +which in nature is like + + + align:start position:0% +which in nature is like +36 mev + + align:start position:0% + + + + align:start position:0% + +greater than zero if you looked at the + + align:start position:0% +greater than zero if you looked at the + + + align:start position:0% +greater than zero if you looked at the +other channel the 1s 0 channel then the + + align:start position:0% +other channel the 1s 0 channel then the + + + align:start position:0% +other channel the 1s 0 channel then the +scatting length was negative + + align:start position:0% +scatting length was negative + + + align:start position:0% +scatting length was negative +so then both terms would be negative and + + align:start position:0% +so then both terms would be negative and + + + align:start position:0% +so then both terms would be negative and +there's no pull + + align:start position:0% + + + + align:start position:0% + +okay so for the 3s1 channel we have a + + align:start position:0% +okay so for the 3s1 channel we have a + + + align:start position:0% +okay so for the 3s1 channel we have a +pole that's the physical deuteron state + + align:start position:0% +pole that's the physical deuteron state + + + align:start position:0% +pole that's the physical deuteron state +for the other channel there is no pull + + align:start position:0% + + + + align:start position:0% + +and the binding energy that you would + + align:start position:0% +and the binding energy that you would + + + align:start position:0% +and the binding energy that you would +get from this is gamma b squared + + align:start position:0% +get from this is gamma b squared + + + align:start position:0% +get from this is gamma b squared +over m with our conventions + + align:start position:0% +over m with our conventions + + + align:start position:0% +over m with our conventions +which + + align:start position:0% +which + + + align:start position:0% +which +if you calculate it is 1.4 mev + + align:start position:0% +if you calculate it is 1.4 mev + + + align:start position:0% +if you calculate it is 1.4 mev +and that's not ridiculously different + + align:start position:0% +and that's not ridiculously different + + + align:start position:0% +and that's not ridiculously different +than the real binding energy of the + + align:start position:0% +than the real binding energy of the + + + align:start position:0% +than the real binding energy of the +deuteron + + align:start position:0% +deuteron + + + align:start position:0% +deuteron +which is 2.2 mev + + align:start position:0% +which is 2.2 mev + + + align:start position:0% +which is 2.2 mev +okay it's not + + align:start position:0% +okay it's not + + + align:start position:0% +okay it's not +it's the right order of magnitude + + align:start position:0% + + + + align:start position:0% + +all right so that's the deuteron it + + align:start position:0% +all right so that's the deuteron it + + + align:start position:0% +all right so that's the deuteron it +exists in this theory and we can + + align:start position:0% +exists in this theory and we can + + + align:start position:0% +exists in this theory and we can +perturbatively correct towards this + + align:start position:0% +perturbatively correct towards this + + + align:start position:0% +perturbatively correct towards this +correct + + align:start position:0% +correct + + + align:start position:0% +correct +mining energy + + align:start position:0% + + + + align:start position:0% + +okay so this deuteron really exists in + + align:start position:0% +okay so this deuteron really exists in + + + align:start position:0% +okay so this deuteron really exists in +the field theory and that means we can + + align:start position:0% +the field theory and that means we can + + + align:start position:0% +the field theory and that means we can +calculate properties of the deuteron + + align:start position:0% +calculate properties of the deuteron + + + align:start position:0% +calculate properties of the deuteron +with this field theory + + align:start position:0% +with this field theory + + + align:start position:0% +with this field theory +we can calculate scattering processes + + align:start position:0% +we can calculate scattering processes + + + align:start position:0% +we can calculate scattering processes +that involve this bound state and it's + + align:start position:0% +that involve this bound state and it's + + + align:start position:0% +that involve this bound state and it's +no more difficult than + + align:start position:0% +no more difficult than + + + align:start position:0% +no more difficult than +doing calculations that we would + + align:start position:0% +doing calculations that we would + + + align:start position:0% +doing calculations that we would +normally do with free fields + + align:start position:0% + + + + align:start position:0% + +and we just have to if we want to do + + align:start position:0% +and we just have to if we want to do + + + align:start position:0% +and we just have to if we want to do +something with the deuteron we have to + + align:start position:0% +something with the deuteron we have to + + + align:start position:0% +something with the deuteron we have to +go to the right pole + + align:start position:0% +go to the right pole + + + align:start position:0% +go to the right pole +that's basically what it boils down to + + align:start position:0% + + + + align:start position:0% + +so in order to show you really how to do + + align:start position:0% +so in order to show you really how to do + + + align:start position:0% +so in order to show you really how to do +that i'm going to give one example + + align:start position:0% +that i'm going to give one example + + + align:start position:0% +that i'm going to give one example +calculating something non-trivial that + + align:start position:0% +calculating something non-trivial that + + + align:start position:0% +calculating something non-trivial that +involves a deuteron + + align:start position:0% + + + + align:start position:0% + +so we'll calculate + + align:start position:0% +so we'll calculate + + + align:start position:0% +so we'll calculate +a form factor for the deuteron + + align:start position:0% + + + + align:start position:0% + +so this is a nice example if you like + + align:start position:0% +so this is a nice example if you like + + + align:start position:0% +so this is a nice example if you like +of really showing you how to use the lsc + + align:start position:0% +of really showing you how to use the lsc + + + align:start position:0% +of really showing you how to use the lsc +formula + + align:start position:0% +formula + + + align:start position:0% +formula +which you learned about in a very sort + + align:start position:0% +which you learned about in a very sort + + + align:start position:0% +which you learned about in a very sort +of abstract way at some point + + align:start position:0% +of abstract way at some point + + + align:start position:0% +of abstract way at some point +how to use it for bound states + + align:start position:0% +how to use it for bound states + + + align:start position:0% +how to use it for bound states +because here we have a bound state + + align:start position:0% +because here we have a bound state + + + align:start position:0% +because here we have a bound state +exists in the theory + + align:start position:0% +exists in the theory + + + align:start position:0% +exists in the theory +and if we want to + + align:start position:0% +and if we want to + + + align:start position:0% +and if we want to +derive properties of that bound state we + + align:start position:0% +derive properties of that bound state we + + + align:start position:0% +derive properties of that bound state we +better properly use the lsd formula for + + align:start position:0% +better properly use the lsd formula for + + + align:start position:0% +better properly use the lsd formula for +that bound state + + align:start position:0% +that bound state + + + align:start position:0% +that bound state +let's see how that works + + align:start position:0% + + + + align:start position:0% + +okay so what we'd like to do + + align:start position:0% +okay so what we'd like to do + + + align:start position:0% +okay so what we'd like to do +is we'd like to have we have some + + align:start position:0% +is we'd like to have we have some + + + align:start position:0% +is we'd like to have we have some +deuteron state and we'd like to take the + + align:start position:0% +deuteron state and we'd like to take the + + + align:start position:0% +deuteron state and we'd like to take the +matrix element with the electromagnetic + + align:start position:0% +matrix element with the electromagnetic + + + align:start position:0% +matrix element with the electromagnetic +current + + align:start position:0% + + + + align:start position:0% + +and if you work out what possible form + + align:start position:0% +and if you work out what possible form + + + align:start position:0% +and if you work out what possible form +factors you can have for this matrix + + align:start position:0% +factors you can have for this matrix + + + align:start position:0% +factors you can have for this matrix +element there's actually three + + align:start position:0% +element there's actually three + + + align:start position:0% +element there's actually three +and i'm not going to spend much time + + align:start position:0% +and i'm not going to spend much time + + + align:start position:0% +and i'm not going to spend much time +talking about the + + align:start position:0% +talking about the + + + align:start position:0% +talking about the +the sort of different couplings with + + align:start position:0% +the sort of different couplings with + + + align:start position:0% +the sort of different couplings with +spin and stuff that correspond to these + + align:start position:0% +spin and stuff that correspond to these + + + align:start position:0% +spin and stuff that correspond to these +different cases but i'll list them for + + align:start position:0% +different cases but i'll list them for + + + align:start position:0% +different cases but i'll list them for +you at least + + align:start position:0% +you at least + + + align:start position:0% +you at least +provide you some additional references + + align:start position:0% +provide you some additional references + + + align:start position:0% +provide you some additional references +if you want to dig deeper into this + + align:start position:0% +if you want to dig deeper into this + + + align:start position:0% +if you want to dig deeper into this +so there's a magnetic electric and + + align:start position:0% +so there's a magnetic electric and + + + align:start position:0% +so there's a magnetic electric and +quadrupole form factor + + align:start position:0% + + + + align:start position:0% + +the charge of the deuteron + + align:start position:0% +the charge of the deuteron + + + align:start position:0% +the charge of the deuteron +tells us that this + + align:start position:0% +tells us that this + + + align:start position:0% +tells us that this +electric form factor at q squared equals + + align:start position:0% +electric form factor at q squared equals + + + align:start position:0% +electric form factor at q squared equals +zero should be one + + align:start position:0% +zero should be one + + + align:start position:0% +zero should be one +the magnetic form factor is like the + + align:start position:0% +the magnetic form factor is like the + + + align:start position:0% +the magnetic form factor is like the +magnetic form factor for electron + + align:start position:0% +magnetic form factor for electron + + + align:start position:0% +magnetic form factor for electron +in the sense that if you go to q squared + + align:start position:0% +in the sense that if you go to q squared + + + align:start position:0% +in the sense that if you go to q squared +equals zero then that's giving you the + + align:start position:0% +equals zero then that's giving you the + + + align:start position:0% +equals zero then that's giving you the +magnetic moment but here it's the + + align:start position:0% +magnetic moment but here it's the + + + align:start position:0% +magnetic moment but here it's the +magnetic moment of the deuteron not the + + align:start position:0% +magnetic moment of the deuteron not the + + + align:start position:0% +magnetic moment of the deuteron not the +magnetic moment of the electron + + align:start position:0% + + + + align:start position:0% + +it's a non-trivial number + + align:start position:0% +it's a non-trivial number + + + align:start position:0% +it's a non-trivial number +in this case whereas here + + align:start position:0% +in this case whereas here + + + align:start position:0% +in this case whereas here +it's just one because charge is + + align:start position:0% +it's just one because charge is + + + align:start position:0% +it's just one because charge is +conserved + + align:start position:0% + + + + align:start position:0% + +and if we wanted to + + align:start position:0% +and if we wanted to + + + align:start position:0% +and if we wanted to +think about putting electromagnetism + + align:start position:0% +think about putting electromagnetism + + + align:start position:0% +think about putting electromagnetism +into the nucleon theory which we haven't + + align:start position:0% +into the nucleon theory which we haven't + + + align:start position:0% +into the nucleon theory which we haven't +so far + + align:start position:0% +so far + + + align:start position:0% +so far +then we would turn our derivatives into + + align:start position:0% +then we would turn our derivatives into + + + align:start position:0% +then we would turn our derivatives into +covariant derivatives so + + align:start position:0% +covariant derivatives so + + + align:start position:0% +covariant derivatives so +d mu nucleon + + align:start position:0% + + + + align:start position:0% + +we have to write down + + align:start position:0% +we have to write down + + + align:start position:0% +we have to write down +a charge matrix that couples that takes + + align:start position:0% +a charge matrix that couples that takes + + + align:start position:0% +a charge matrix that couples that takes +into account the proton has charge but + + align:start position:0% +into account the proton has charge but + + + align:start position:0% +into account the proton has charge but +the neutron doesn't + + align:start position:0% + + + + align:start position:0% + +so this is + + align:start position:0% +so this is + + + align:start position:0% +so this is +that charge matrix + + align:start position:0% +that charge matrix + + + align:start position:0% +that charge matrix +for electromagnetism + + align:start position:0% +for electromagnetism + + + align:start position:0% +for electromagnetism +okay so it's not + + align:start position:0% +okay so it's not + + + align:start position:0% +okay so it's not +difficult so that's easy enough just + + align:start position:0% +difficult so that's easy enough just + + + align:start position:0% +difficult so that's easy enough just +change your derivatives into covariant + + align:start position:0% +change your derivatives into covariant + + + align:start position:0% +change your derivatives into covariant +derivatives + + align:start position:0% +derivatives + + + align:start position:0% +derivatives +for both d 0 and d partial and d + + align:start position:0% +for both d 0 and d partial and d + + + align:start position:0% +for both d 0 and d partial and d +vector + + align:start position:0% +vector + + + align:start position:0% +vector +there's also some additional operators + + align:start position:0% +there's also some additional operators + + + align:start position:0% +there's also some additional operators +that you have to write down + + align:start position:0% +that you have to write down + + + align:start position:0% +that you have to write down +so there's + + align:start position:0% + + + + align:start position:0% + +operators for example that are just + + align:start position:0% +operators for example that are just + + + align:start position:0% +operators for example that are just +contact interactions with the magnetic + + align:start position:0% +contact interactions with the magnetic + + + align:start position:0% +contact interactions with the magnetic +with the electric magnetic fields in + + align:start position:0% +with the electric magnetic fields in + + + align:start position:0% +with the electric magnetic fields in +principle + + align:start position:0% +principle + + + align:start position:0% +principle +and the first such one + + align:start position:0% +and the first such one + + + align:start position:0% +and the first such one +that shows up + + align:start position:0% + + + + align:start position:0% + +just by way of sort of telling you + + align:start position:0% +just by way of sort of telling you + + + align:start position:0% +just by way of sort of telling you +a range of possibilities would be + + align:start position:0% +a range of possibilities would be + + + align:start position:0% +a range of possibilities would be +something like this where you just have + + align:start position:0% +something like this where you just have + + + align:start position:0% +something like this where you just have +a sigma.b magnetic field insertion + + align:start position:0% +a sigma.b magnetic field insertion + + + align:start position:0% +a sigma.b magnetic field insertion +this is the + + align:start position:0% +this is the + + + align:start position:0% +this is the +magnetic field + + align:start position:0% +magnetic field + + + align:start position:0% +magnetic field +for electromagnetism + + align:start position:0% + + + + align:start position:0% + +and so if you want to think about the + + align:start position:0% +and so if you want to think about the + + + align:start position:0% +and so if you want to think about the +type of finemen diagram you'd draw for + + align:start position:0% +type of finemen diagram you'd draw for + + + align:start position:0% +type of finemen diagram you'd draw for +this you'd have four nucleons and then + + align:start position:0% +this you'd have four nucleons and then + + + align:start position:0% +this you'd have four nucleons and then +you just have a photon + + align:start position:0% +you just have a photon + + + align:start position:0% +you just have a photon +coming out right + + align:start position:0% +coming out right + + + align:start position:0% +coming out right +if you want to think about where that + + align:start position:0% +if you want to think about where that + + + align:start position:0% +if you want to think about where that +could possibly come from + + align:start position:0% + + + + align:start position:0% + +there's one really easy thing to think + + align:start position:0% +there's one really easy thing to think + + + align:start position:0% +there's one really easy thing to think +about would just be to have a pioneer + + align:start position:0% +about would just be to have a pioneer + + + align:start position:0% +about would just be to have a pioneer +exchange + + align:start position:0% +exchange + + + align:start position:0% +exchange +and maybe it's a pi minus + + align:start position:0% + + + + align:start position:0% + +and the + + align:start position:0% +and the + + + align:start position:0% +and the +photon couples to a pi minus because + + align:start position:0% +photon couples to a pi minus because + + + align:start position:0% +photon couples to a pi minus because +it's got electric charge + + align:start position:0% +it's got electric charge + + + align:start position:0% +it's got electric charge +and when i integrate out the pion then i + + align:start position:0% +and when i integrate out the pion then i + + + align:start position:0% +and when i integrate out the pion then i +just get something that looks like this + + align:start position:0% +just get something that looks like this + + + align:start position:0% +just get something that looks like this +could be any exchange it could be a real + + align:start position:0% +could be any exchange it could be a real + + + align:start position:0% +could be any exchange it could be a real +minus + + align:start position:0% +minus + + + align:start position:0% +minus +anything would give an operator it looks + + align:start position:0% +anything would give an operator it looks + + + align:start position:0% +anything would give an operator it looks +like that + + align:start position:0% +like that + + + align:start position:0% +like that +okay so there's additional contact + + align:start position:0% +okay so there's additional contact + + + align:start position:0% +okay so there's additional contact +interactions involving electromagnetism + + align:start position:0% +interactions involving electromagnetism + + + align:start position:0% +interactions involving electromagnetism +then you gauge the gauge the derivatives + + align:start position:0% +then you gauge the gauge the derivatives + + + align:start position:0% +then you gauge the gauge the derivatives +then you can put electromagnetism into + + align:start position:0% +then you can put electromagnetism into + + + align:start position:0% +then you can put electromagnetism into +the theory + + align:start position:0% +the theory + + + align:start position:0% +the theory +it's a little more non-trivial then + + align:start position:0% + + + + align:start position:0% + +and that's what we need to do if we want + + align:start position:0% +and that's what we need to do if we want + + + align:start position:0% +and that's what we need to do if we want +to talk about electromagnetism coupling + + align:start position:0% +to talk about electromagnetism coupling + + + align:start position:0% +to talk about electromagnetism coupling +for the deuteron + + align:start position:0% +for the deuteron + + + align:start position:0% +for the deuteron +but i'm mostly interested here in how + + align:start position:0% +but i'm mostly interested here in how + + + align:start position:0% +but i'm mostly interested here in how +the llc works + + align:start position:0% +the llc works + + + align:start position:0% +the llc works +so what does lz say + + align:start position:0% +so what does lz say + + + align:start position:0% +so what does lz say +so lsc says that if i have this state p + + align:start position:0% +so lsc says that if i have this state p + + + align:start position:0% +so lsc says that if i have this state p +prime + + align:start position:0% +prime + + + align:start position:0% +prime +j out + + align:start position:0% +j out + + + align:start position:0% +j out +jmu electromagnetism + + align:start position:0% +jmu electromagnetism + + + align:start position:0% +jmu electromagnetism +p + + align:start position:0% +p + + + align:start position:0% +p +i n + + align:start position:0% +i n + + + align:start position:0% +i n +i is like a spin index because we have a + + align:start position:0% +i is like a spin index because we have a + + + align:start position:0% +i is like a spin index because we have a +triplet under spin + + align:start position:0% + + + + align:start position:0% + +then + + align:start position:0% +then + + + align:start position:0% +then +this is how you should calculate it + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +q is like the + + align:start position:0% +q is like the + + + align:start position:0% +q is like the +well i guess i'm in momentum space all + + align:start position:0% +well i guess i'm in momentum space all + + + align:start position:0% +well i guess i'm in momentum space all +of a sudden + + align:start position:0% +of a sudden + + + align:start position:0% +of a sudden +well no q is just a p p minus p prime + + align:start position:0% +well no q is just a p p minus p prime + + + align:start position:0% +well no q is just a p p minus p prime +e and e bar are related to the p and the + + align:start position:0% +e and e bar are related to the p and the + + + align:start position:0% +e and e bar are related to the p and the +p prime also + + align:start position:0% +p prime also + + + align:start position:0% +p prime also +and what i do is i have some z factor + + align:start position:0% +and what i do is i have some z factor + + + align:start position:0% +and what i do is i have some z factor +out front which is the bound state z + + align:start position:0% +out front which is the bound state z + + + align:start position:0% +out front which is the bound state z +factor + + align:start position:0% + + + + align:start position:0% + +lsd tells me to be careful about that c + + align:start position:0% +lsd tells me to be careful about that c + + + align:start position:0% +lsd tells me to be careful about that c +factor + + align:start position:0% +factor + + + align:start position:0% +factor +these guys here are just two point + + align:start position:0% +these guys here are just two point + + + align:start position:0% +these guys here are just two point +functions and that's because i have to + + align:start position:0% +functions and that's because i have to + + + align:start position:0% +functions and that's because i have to +truncate + + align:start position:0% +truncate + + + align:start position:0% +truncate +the lines + + align:start position:0% + + + + align:start position:0% + +this is truncation by two point + + align:start position:0% +this is truncation by two point + + + align:start position:0% +this is truncation by two point +functions + + align:start position:0% +functions + + + align:start position:0% +functions +but they're two point functions for the + + align:start position:0% +but they're two point functions for the + + + align:start position:0% +but they're two point functions for the +bound states of two lines + + align:start position:0% +bound states of two lines + + + align:start position:0% +bound states of two lines +and then this is the three point + + align:start position:0% +and then this is the three point + + + align:start position:0% +and then this is the three point +functions + + align:start position:0% + + + + align:start position:0% + +okay so for the three point functions + + align:start position:0% + + + + align:start position:0% + +what would the time order product be for + + align:start position:0% +what would the time order product be for + + + align:start position:0% +what would the time order product be for +that + + align:start position:0% + + + + align:start position:0% + +it's a time warner product of three + + align:start position:0% +it's a time warner product of three + + + align:start position:0% +it's a time warner product of three +things + + align:start position:0% + + + + align:start position:0% + +so the two point function we already + + align:start position:0% +so the two point function we already + + + align:start position:0% +so the two point function we already +defined it was just a time order product + + align:start position:0% +defined it was just a time order product + + + align:start position:0% +defined it was just a time order product +of the two deuteron fields + + align:start position:0% +of the two deuteron fields + + + align:start position:0% +of the two deuteron fields +and the three-point function has an + + align:start position:0% +and the three-point function has an + + + align:start position:0% +and the three-point function has an +additional + + align:start position:0% +additional + + + align:start position:0% +additional +electromagnetic current + + align:start position:0% + + + + align:start position:0% + +which we would formulate you know all + + align:start position:0% +which we would formulate you know all + + + align:start position:0% +which we would formulate you know all +the couplings here this way that i was + + align:start position:0% +the couplings here this way that i was + + + align:start position:0% +the couplings here this way that i was +talking about over there + + align:start position:0% + + + + align:start position:0% + +so in terms of diagrams which are easier + + align:start position:0% +so in terms of diagrams which are easier + + + align:start position:0% +so in terms of diagrams which are easier +to think about in + + align:start position:0% +to think about in + + + align:start position:0% +to think about in +some ways than time order products + + align:start position:0% +some ways than time order products + + + align:start position:0% +some ways than time order products +we have the two point function + + align:start position:0% +we have the two point function + + + align:start position:0% +we have the two point function +which if i just define all possible two + + align:start position:0% +which if i just define all possible two + + + align:start position:0% +which if i just define all possible two +functions as g + + align:start position:0% +functions as g + + + align:start position:0% +functions as g +and this is the thing that + + align:start position:0% +and this is the thing that + + + align:start position:0% +and this is the thing that +was our two particle was our irreducible + + align:start position:0% +was our two particle was our irreducible + + + align:start position:0% +was our two particle was our irreducible +c zero contributions plus iterations of + + align:start position:0% +c zero contributions plus iterations of + + + align:start position:0% +c zero contributions plus iterations of +c zeros + + align:start position:0% +c zeros + + + align:start position:0% +c zeros +all right since the c zero is a + + align:start position:0% +all right since the c zero is a + + + align:start position:0% +all right since the c zero is a +non-perturbative coupling we have to + + align:start position:0% +non-perturbative coupling we have to + + + align:start position:0% +non-perturbative coupling we have to +iterate + + align:start position:0% +iterate + + + align:start position:0% +iterate +and this is what we already + + align:start position:0% +and this is what we already + + + align:start position:0% +and this is what we already +said you could define as + + align:start position:0% +said you could define as + + + align:start position:0% +said you could define as +summing up that geometric series and + + align:start position:0% +summing up that geometric series and + + + align:start position:0% +summing up that geometric series and +then just define it as something which + + align:start position:0% +then just define it as something which + + + align:start position:0% +then just define it as something which +is the full greens function in terms of + + align:start position:0% +is the full greens function in terms of + + + align:start position:0% +is the full greens function in terms of +this irreducible piece in the usual sort + + align:start position:0% +this irreducible piece in the usual sort + + + align:start position:0% +this irreducible piece in the usual sort +of way + + align:start position:0% +of way + + + align:start position:0% +of way +and then for this other g + + align:start position:0% + + + + align:start position:0% + +i'll draw a blob which i'll also call g + + align:start position:0% +i'll draw a blob which i'll also call g + + + align:start position:0% +i'll draw a blob which i'll also call g +but with an additional photon hanging + + align:start position:0% +but with an additional photon hanging + + + align:start position:0% +but with an additional photon hanging +out + + align:start position:0% +out + + + align:start position:0% +out +those are all three point functions + + align:start position:0% +those are all three point functions + + + align:start position:0% +those are all three point functions +and in a kind of similar notation + + align:start position:0% +and in a kind of similar notation + + + align:start position:0% +and in a kind of similar notation +i can have kind of an irreducible + + align:start position:0% +i can have kind of an irreducible + + + align:start position:0% +i can have kind of an irreducible +piece + + align:start position:0% +piece + + + align:start position:0% +piece +and then i can have iterations + + align:start position:0% +and then i can have iterations + + + align:start position:0% +and then i can have iterations +with c zeros + + align:start position:0% + + + + align:start position:0% + +etc + + align:start position:0% + + + + align:start position:0% + +and if i sum up those irreducible + + align:start position:0% +and if i sum up those irreducible + + + align:start position:0% +and if i sum up those irreducible +diagrams i can write the full greens + + align:start position:0% +diagrams i can write the full greens + + + align:start position:0% +diagrams i can write the full greens +function in terms of the irreducible + + align:start position:0% +function in terms of the irreducible + + + align:start position:0% +function in terms of the irreducible +pieces again in a similar sort of + + align:start position:0% +pieces again in a similar sort of + + + align:start position:0% +pieces again in a similar sort of +notation + + align:start position:0% +notation + + + align:start position:0% +notation +it's just gamma which carries the + + align:start position:0% +it's just gamma which carries the + + + align:start position:0% +it's just gamma which carries the +indices + + align:start position:0% +indices + + + align:start position:0% +indices +and then there's just + + align:start position:0% + + + + align:start position:0% + +a couple of now there's geometric series + + align:start position:0% +a couple of now there's geometric series + + + align:start position:0% +a couple of now there's geometric series +on both sides so when i sum them up i + + align:start position:0% +on both sides so when i sum them up i + + + align:start position:0% +on both sides so when i sum them up i +get that + + align:start position:0% + + + + align:start position:0% + +okay so this is giving you the + + align:start position:0% +okay so this is giving you the + + + align:start position:0% +okay so this is giving you the +ingredients that we need to plug into + + align:start position:0% +ingredients that we need to plug into + + + align:start position:0% +ingredients that we need to plug into +this formula we need g inverse this is g + + align:start position:0% +this formula we need g inverse this is g + + + align:start position:0% +this formula we need g inverse this is g +the two point + + align:start position:0% +the two point + + + align:start position:0% +the two point +we need the g mu i j which we can write + + align:start position:0% +we need the g mu i j which we can write + + + align:start position:0% +we need the g mu i j which we can write +in terms of the irreducible guy like + + align:start position:0% +in terms of the irreducible guy like + + + align:start position:0% +in terms of the irreducible guy like +that and then the last thing we need is + + align:start position:0% +that and then the last thing we need is + + + align:start position:0% +that and then the last thing we need is +this bound state z factor + + align:start position:0% + + + + align:start position:0% + +uh + + align:start position:0% +uh + + + align:start position:0% +uh +yeah what i really i'm kind of using a + + align:start position:0% +yeah what i really i'm kind of using a + + + align:start position:0% +yeah what i really i'm kind of using a +shorthand here with this t product for + + align:start position:0% +shorthand here with this t product for + + + align:start position:0% +shorthand here with this t product for +all the diagrams that come from what i + + align:start position:0% +all the diagrams that come from what i + + + align:start position:0% +all the diagrams that come from what i +was talking about over there + + align:start position:0% +was talking about over there + + + align:start position:0% +was talking about over there +yeah i kind of wrote it as an + + align:start position:0% +yeah i kind of wrote it as an + + + align:start position:0% +yeah i kind of wrote it as an +electromagnetic current but really what + + align:start position:0% +electromagnetic current but really what + + + align:start position:0% +electromagnetic current but really what +i mean by it is sort of all the ways + + align:start position:0% +i mean by it is sort of all the ways + + + align:start position:0% +i mean by it is sort of all the ways +that electromagnetism can appear in the + + align:start position:0% +that electromagnetism can appear in the + + + align:start position:0% +that electromagnetism can appear in the +effective theory + + align:start position:0% + + + + align:start position:0% + +so you can think of formulating a + + align:start position:0% +so you can think of formulating a + + + align:start position:0% +so you can think of formulating a +current in the effective theory + + align:start position:0% +current in the effective theory + + + align:start position:0% +current in the effective theory +by just sort of take looking for one + + align:start position:0% +by just sort of take looking for one + + + align:start position:0% +by just sort of take looking for one +photon lopping it off and then writing + + align:start position:0% +photon lopping it off and then writing + + + align:start position:0% +photon lopping it off and then writing +down that operator all the operators and + + align:start position:0% +down that operator all the operators and + + + align:start position:0% +down that operator all the operators and +that's what really what i mean by this + + align:start position:0% +that's what really what i mean by this + + + align:start position:0% +that's what really what i mean by this +yeah + + align:start position:0% + + + + align:start position:0% + +any other questions + + align:start position:0% + + + + align:start position:0% + +okay so what's the final thing we need + + align:start position:0% +okay so what's the final thing we need + + + align:start position:0% +okay so what's the final thing we need +which is the bound state z factor + + align:start position:0% +which is the bound state z factor + + + align:start position:0% +which is the bound state z factor +so that's + + align:start position:0% +so that's + + + align:start position:0% +so that's +when we look back at this kind of form + + align:start position:0% +when we look back at this kind of form + + + align:start position:0% +when we look back at this kind of form +that we had for + + align:start position:0% + + + + align:start position:0% + +for g we said it's i z but now let's + + align:start position:0% +for g we said it's i z but now let's + + + align:start position:0% +for g we said it's i z but now let's +denote the fact that z is really a + + align:start position:0% +denote the fact that z is really a + + + align:start position:0% +denote the fact that z is really a +principle a function of e bar + + align:start position:0% +principle a function of e bar + + + align:start position:0% +principle a function of e bar +and it's really the residue of the pole + + align:start position:0% +and it's really the residue of the pole + + + align:start position:0% +and it's really the residue of the pole +and what z + + align:start position:0% +and what z + + + align:start position:0% +and what z +is + + align:start position:0% +is + + + align:start position:0% +is +z that appears in the formula over there + + align:start position:0% +z that appears in the formula over there + + + align:start position:0% +z that appears in the formula over there +it's z at the pole + + align:start position:0% +it's z at the pole + + + align:start position:0% +it's z at the pole +so that's where i set + + align:start position:0% +so that's where i set + + + align:start position:0% +so that's where i set +e bar equal to minus bd in the numerator + + align:start position:0% +e bar equal to minus bd in the numerator + + + align:start position:0% +e bar equal to minus bd in the numerator +so this is the residue of the pole + + align:start position:0% + + + + align:start position:0% + +and with a little bit of manipulation we + + align:start position:0% +and with a little bit of manipulation we + + + align:start position:0% +and with a little bit of manipulation we +can write that as the following + + align:start position:0% + + + + align:start position:0% + +you can relate it to a derivative + + align:start position:0% + + + + align:start position:0% + +at the pole + + align:start position:0% +at the pole + + + align:start position:0% +at the pole +okay so take the inverse + + align:start position:0% +okay so take the inverse + + + align:start position:0% +okay so take the inverse +take a derivative to sort of get just + + align:start position:0% +take a derivative to sort of get just + + + align:start position:0% +take a derivative to sort of get just +this factor take an inverse again we can + + align:start position:0% +this factor take an inverse again we can + + + align:start position:0% +this factor take an inverse again we can +extract off that residue + + align:start position:0% +extract off that residue + + + align:start position:0% +extract off that residue +killing off some other pieces by going + + align:start position:0% +killing off some other pieces by going + + + align:start position:0% +killing off some other pieces by going +to the pole + + align:start position:0% +to the pole + + + align:start position:0% +to the pole +okay so i won't go through the + + align:start position:0% +okay so i won't go through the + + + align:start position:0% +okay so i won't go through the +derivation of that little manipulation + + align:start position:0% +derivation of that little manipulation + + + align:start position:0% +derivation of that little manipulation +but + + align:start position:0% +but + + + align:start position:0% +but +it's a straightforward consequence + + align:start position:0% +it's a straightforward consequence + + + align:start position:0% +it's a straightforward consequence +and if you put in + + align:start position:0% +and if you put in + + + align:start position:0% +and if you put in +kind of the formula that we had over + + align:start position:0% +kind of the formula that we had over + + + align:start position:0% +kind of the formula that we had over +here for g + + align:start position:0% +here for g + + + align:start position:0% +here for g +and you do that then you can write a + + align:start position:0% +and you do that then you can write a + + + align:start position:0% +and you do that then you can write a +formula in terms of sigma + + align:start position:0% + + + + align:start position:0% + +and after that kind of manipulation it's + + align:start position:0% + + + + align:start position:0% + +again just some algebra to show that + + align:start position:0% +again just some algebra to show that + + + align:start position:0% +again just some algebra to show that +this is true + + align:start position:0% + + + + align:start position:0% + +so now we can put all the pieces + + align:start position:0% +so now we can put all the pieces + + + align:start position:0% +so now we can put all the pieces +together we have this formula + + align:start position:0% + + + + align:start position:0% + +get this formula + + align:start position:0% +get this formula + + + align:start position:0% +get this formula +this formula + + align:start position:0% + + + + align:start position:0% + +put them into the formula up there + + align:start position:0% +put them into the formula up there + + + align:start position:0% +put them into the formula up there +and what we find + + align:start position:0% +and what we find + + + align:start position:0% +and what we find +is that + + align:start position:0% + + + + align:start position:0% + +we can write the kind of result of it + + align:start position:0% +we can write the kind of result of it + + + align:start position:0% +we can write the kind of result of it +using lsd in a kind of very compact way + + align:start position:0% +using lsd in a kind of very compact way + + + align:start position:0% +using lsd in a kind of very compact way +just in terms of irreducible things + + align:start position:0% +just in terms of irreducible things + + + align:start position:0% +just in terms of irreducible things +c0 irreducible things + + align:start position:0% + + + + align:start position:0% + +and + + align:start position:0% +and + + + align:start position:0% +and +it's not just the irreducible + + align:start position:0% +it's not just the irreducible + + + align:start position:0% +it's not just the irreducible +three-point functions there is a + + align:start position:0% +three-point functions there is a + + + align:start position:0% +three-point functions there is a +contribution from the two-point function + + align:start position:0% +contribution from the two-point function + + + align:start position:0% +contribution from the two-point function +which is + + align:start position:0% +which is + + + align:start position:0% +which is +in this case d sigma-d bar + + align:start position:0% +in this case d sigma-d bar + + + align:start position:0% +in this case d sigma-d bar +where you take + + align:start position:0% +where you take + + + align:start position:0% +where you take +e-bar and e-bar prime incoming and + + align:start position:0% +e-bar and e-bar prime incoming and + + + align:start position:0% +e-bar and e-bar prime incoming and +outgoing energies to be + + align:start position:0% +outgoing energies to be + + + align:start position:0% +outgoing energies to be +the right energies for the bound states + + align:start position:0% +the right energies for the bound states + + + align:start position:0% +the right energies for the bound states +which is + + align:start position:0% +which is + + + align:start position:0% +which is +minus the binding energy + + align:start position:0% +minus the binding energy + + + align:start position:0% +minus the binding energy +okay so the + + align:start position:0% +okay so the + + + align:start position:0% +okay so the +this factor came from here + + align:start position:0% +this factor came from here + + + align:start position:0% +this factor came from here +there's a sigma squared in the numerator + + align:start position:0% +there's a sigma squared in the numerator + + + align:start position:0% +there's a sigma squared in the numerator +but when i take the inverse of two of + + align:start position:0% +but when i take the inverse of two of + + + align:start position:0% +but when i take the inverse of two of +these guys there's a sigma squared in + + align:start position:0% +these guys there's a sigma squared in + + + align:start position:0% +these guys there's a sigma squared in +the denominator and those cancelled + + align:start position:0% +the denominator and those cancelled + + + align:start position:0% +the denominator and those cancelled +the inverse of these guys also had + + align:start position:0% +the inverse of these guys also had + + + align:start position:0% +the inverse of these guys also had +factors of one plus i c zero sigma in + + align:start position:0% +factors of one plus i c zero sigma in + + + align:start position:0% +factors of one plus i c zero sigma in +the numerator and that canceled these + + align:start position:0% +the numerator and that canceled these + + + align:start position:0% +the numerator and that canceled these +factors here + + align:start position:0% +factors here + + + align:start position:0% +factors here +so the only thing left is the gamma + + align:start position:0% +so the only thing left is the gamma + + + align:start position:0% +so the only thing left is the gamma +and the d sigma d e bar + + align:start position:0% +and the d sigma d e bar + + + align:start position:0% +and the d sigma d e bar +okay so that's what lsc says + + align:start position:0% +okay so that's what lsc says + + + align:start position:0% +okay so that's what lsc says +in this situation + + align:start position:0% + + + + align:start position:0% + +and it's actually important to take this + + align:start position:0% +and it's actually important to take this + + + align:start position:0% +and it's actually important to take this +factor into account if you didn't take + + align:start position:0% +factor into account if you didn't take + + + align:start position:0% +factor into account if you didn't take +this factor into account you wouldn't + + align:start position:0% +this factor into account you wouldn't + + + align:start position:0% +this factor into account you wouldn't +even preserve for example that the + + align:start position:0% +even preserve for example that the + + + align:start position:0% +even preserve for example that the +charge of the deuteron is one + + align:start position:0% +charge of the deuteron is one + + + align:start position:0% +charge of the deuteron is one +i mean it's quite important + + align:start position:0% + + + + align:start position:0% + +if you look at this at lowest order + + align:start position:0% +if you look at this at lowest order + + + align:start position:0% +if you look at this at lowest order +and you just look at the electromagnetic + + align:start position:0% +and you just look at the electromagnetic + + + align:start position:0% +and you just look at the electromagnetic +current for the electric case + + align:start position:0% + + + + align:start position:0% + +and you can do that with j0 + + align:start position:0% +and you can do that with j0 + + + align:start position:0% +and you can do that with j0 +looking at the d0 + + align:start position:0% + + + + align:start position:0% + +and we can + + align:start position:0% +and we can + + + align:start position:0% +and we can +use our previous calculations + + align:start position:0% +use our previous calculations + + + align:start position:0% +use our previous calculations +to figure out what + + align:start position:0% +to figure out what + + + align:start position:0% +to figure out what +the two point function is + + align:start position:0% + + + + align:start position:0% + +and + + align:start position:0% +and + + + align:start position:0% +and +when i go to the poll + + align:start position:0% + + + + align:start position:0% + +it's just + + align:start position:0% + + + + align:start position:0% + +this factor where gamma b would be set + + align:start position:0% +this factor where gamma b would be set + + + align:start position:0% +this factor where gamma b would be set +equal to exactly the + + align:start position:0% +equal to exactly the + + + align:start position:0% +equal to exactly the +binding energy + + align:start position:0% + + + + align:start position:0% + +okay so that's just from + + align:start position:0% + + + + align:start position:0% + +the trivial + + align:start position:0% +the trivial + + + align:start position:0% +the trivial +diagram + + align:start position:0% +diagram + + + align:start position:0% +diagram +and then the first contribution that + + align:start position:0% +and then the first contribution that + + + align:start position:0% +and then the first contribution that +comes into the + + align:start position:0% +comes into the + + + align:start position:0% +comes into the +three-point function + + align:start position:0% +three-point function + + + align:start position:0% +three-point function +can be calculated it's pretty + + align:start position:0% +can be calculated it's pretty + + + align:start position:0% +can be calculated it's pretty +straightforward + + align:start position:0% + + + + align:start position:0% + +it gives a tan inverse actually + + align:start position:0% + + + + align:start position:0% + +and that just comes from + + align:start position:0% +and that just comes from + + + align:start position:0% +and that just comes from +coupling + + align:start position:0% +coupling + + + align:start position:0% +coupling +to the + + align:start position:0% +to the + + + align:start position:0% +to the +electromagnetic proton that's inside the + + align:start position:0% +electromagnetic proton that's inside the + + + align:start position:0% +electromagnetic proton that's inside the +deuteron so this is the proton + + align:start position:0% +deuteron so this is the proton + + + align:start position:0% +deuteron so this is the proton +which has an electromagnetic coupling + + align:start position:0% +which has an electromagnetic coupling + + + align:start position:0% +which has an electromagnetic coupling +this is the neutron + + align:start position:0% +this is the neutron + + + align:start position:0% +this is the neutron +okay and that gives this formula take + + align:start position:0% +okay and that gives this formula take + + + align:start position:0% +okay and that gives this formula take +the ratio you get the lowest order form + + align:start position:0% +the ratio you get the lowest order form + + + align:start position:0% +the ratio you get the lowest order form +factor + + align:start position:0% +factor + + + align:start position:0% +factor +this is a systematically improvable + + align:start position:0% +this is a systematically improvable + + + align:start position:0% +this is a systematically improvable +thing so you can do nlo + + align:start position:0% + + + + align:start position:0% + +you can do an nlo et cetera + + align:start position:0% +you can do an nlo et cetera + + + align:start position:0% +you can do an nlo et cetera +okay so we can really calculate + + align:start position:0% +okay so we can really calculate + + + align:start position:0% +okay so we can really calculate +properties of the deuteron + + align:start position:0% +properties of the deuteron + + + align:start position:0% +properties of the deuteron +and check whether they work + + align:start position:0% +and check whether they work + + + align:start position:0% +and check whether they work +experimentally and this works extremely + + align:start position:0% +experimentally and this works extremely + + + align:start position:0% +experimentally and this works extremely +well experimentally + + align:start position:0% + + + + align:start position:0% + +you actually don't see the + + align:start position:0% +you actually don't see the + + + align:start position:0% +you actually don't see the +violation of charge conjugation + + align:start position:0% +violation of charge conjugation + + + align:start position:0% +violation of charge conjugation +conservation in the form factor until + + align:start position:0% +conservation in the form factor until + + + align:start position:0% +conservation in the form factor until +you do nlo then you really see that you + + align:start position:0% +you do nlo then you really see that you + + + align:start position:0% +you do nlo then you really see that you +need this + + align:start position:0% +need this + + + align:start position:0% +need this +guy in order to make sure that the + + align:start position:0% +guy in order to make sure that the + + + align:start position:0% +guy in order to make sure that the +charge is conserved + + align:start position:0% + + + + align:start position:0% + +there would be some pieces that would + + align:start position:0% +there would be some pieces that would + + + align:start position:0% +there would be some pieces that would +show up that would seem like they were + + align:start position:0% +show up that would seem like they were + + + align:start position:0% +show up that would seem like they were +correcting the charge violating + + align:start position:0% +correcting the charge violating + + + align:start position:0% +correcting the charge violating +electromagnetism + + align:start position:0% +electromagnetism + + + align:start position:0% +electromagnetism +magnetic gauging variance until you but + + align:start position:0% +magnetic gauging variance until you but + + + align:start position:0% +magnetic gauging variance until you but +then when you put the z factor in + + align:start position:0% + + + + align:start position:0% + +the z factor contribution and everything + + align:start position:0% +the z factor contribution and everything + + + align:start position:0% +the z factor contribution and everything +is nice + + align:start position:0% + + + + align:start position:0% + +and this theory has actually been used + + align:start position:0% +and this theory has actually been used + + + align:start position:0% +and this theory has actually been used +to do phenomenology + + align:start position:0% +to do phenomenology + + + align:start position:0% +to do phenomenology +so + + align:start position:0% + + + + align:start position:0% + +just to give you some examples of that + + align:start position:0% + + + + align:start position:0% + +so you can do a process like + + align:start position:0% +so you can do a process like + + + align:start position:0% +so you can do a process like +neutron on proton + + align:start position:0% +neutron on proton + + + align:start position:0% +neutron on proton +produces a deuteron and a photon which + + align:start position:0% +produces a deuteron and a photon which + + + align:start position:0% +produces a deuteron and a photon which +is something that shows up in big bang + + align:start position:0% +is something that shows up in big bang + + + align:start position:0% +is something that shows up in big bang +nuclear synthesis + + align:start position:0% +nuclear synthesis + + + align:start position:0% +nuclear synthesis +and it's been calculated to n4lo + + align:start position:0% +and it's been calculated to n4lo + + + align:start position:0% +and it's been calculated to n4lo +in this effective field theory + + align:start position:0% +in this effective field theory + + + align:start position:0% +in this effective field theory +okay and it provides the most accurate + + align:start position:0% +okay and it provides the most accurate + + + align:start position:0% +okay and it provides the most accurate +way of determining + + align:start position:0% +way of determining + + + align:start position:0% +way of determining +the process for big bang blue synthesis + + align:start position:0% +the process for big bang blue synthesis + + + align:start position:0% +the process for big bang blue synthesis +you can reverse it + + align:start position:0% +you can reverse it + + + align:start position:0% +you can reverse it +talk about deuteron breakup + + align:start position:0% +talk about deuteron breakup + + + align:start position:0% +talk about deuteron breakup +you could do processes with neutrinos on + + align:start position:0% +you could do processes with neutrinos on + + + align:start position:0% +you could do processes with neutrinos on +deuterons + + align:start position:0% + + + + align:start position:0% + +so you could have neutrinos deuteron + + align:start position:0% +so you could have neutrinos deuteron + + + align:start position:0% +so you could have neutrinos deuteron +scattering to proton proton e minus + + align:start position:0% +scattering to proton proton e minus + + + align:start position:0% +scattering to proton proton e minus +which is + + align:start position:0% +which is + + + align:start position:0% +which is +the charge current process at snow + + align:start position:0% +the charge current process at snow + + + align:start position:0% +the charge current process at snow +or the neutral current process of snow + + align:start position:0% + + + + align:start position:0% + +all these things are within the realm of + + align:start position:0% +all these things are within the realm of + + + align:start position:0% +all these things are within the realm of +things that you can talk about in this + + align:start position:0% +things that you can talk about in this + + + align:start position:0% +things that you can talk about in this +effective field theory + + align:start position:0% +effective field theory + + + align:start position:0% +effective field theory +okay so it has some uses + + align:start position:0% +okay so it has some uses + + + align:start position:0% +okay so it has some uses +let me do one more + + align:start position:0% +let me do one more + + + align:start position:0% +let me do one more +process + + align:start position:0% + + + + align:start position:0% + +so you could look at neutron nucleon + + align:start position:0% +so you could look at neutron nucleon + + + align:start position:0% +so you could look at neutron nucleon +nucleon + + align:start position:0% +nucleon + + + align:start position:0% +nucleon +to nucleon nucleon plus an axon + + align:start position:0% + + + + align:start position:0% + +and there's sort of a + + align:start position:0% +and there's sort of a + + + align:start position:0% +and there's sort of a +lesson here + + align:start position:0% +lesson here + + + align:start position:0% +lesson here +so if you look at how the axion couples + + align:start position:0% +so if you look at how the axion couples + + + align:start position:0% +so if you look at how the axion couples +to the nucleon + + align:start position:0% +to the nucleon + + + align:start position:0% +to the nucleon +it's derivatively coupled + + align:start position:0% +it's derivatively coupled + + + align:start position:0% +it's derivatively coupled +so you have + + align:start position:0% +so you have + + + align:start position:0% +so you have +a gradient of the axion field + + align:start position:0% + + + + align:start position:0% + +and there's two possible couplings that + + align:start position:0% +and there's two possible couplings that + + + align:start position:0% +and there's two possible couplings that +you can write down just consider the + + align:start position:0% +you can write down just consider the + + + align:start position:0% +you can write down just consider the +sort of lowest dimension + + align:start position:0% +sort of lowest dimension + + + align:start position:0% +sort of lowest dimension +in our power counting + + align:start position:0% + + + + align:start position:0% + +and this is a process that actually is + + align:start position:0% +and this is a process that actually is + + + align:start position:0% +and this is a process that actually is +important for bounding axion physics + + align:start position:0% +important for bounding axion physics + + + align:start position:0% +important for bounding axion physics +for example axions in the sun + + align:start position:0% + + + + align:start position:0% + +worry about how they couple to nucleons + + align:start position:0% +worry about how they couple to nucleons + + + align:start position:0% +worry about how they couple to nucleons +and + + align:start position:0% +and + + + align:start position:0% +and +the thing that's actually important is + + align:start position:0% +the thing that's actually important is + + + align:start position:0% +the thing that's actually important is +if you're thinking about this kind of + + align:start position:0% +if you're thinking about this kind of + + + align:start position:0% +if you're thinking about this kind of +process you have to decide kinematically + + align:start position:0% +process you have to decide kinematically + + + align:start position:0% +process you have to decide kinematically +what region are you looking at if you're + + align:start position:0% +what region are you looking at if you're + + + align:start position:0% +what region are you looking at if you're +interested in bounds from the sun + + align:start position:0% +interested in bounds from the sun + + + align:start position:0% +interested in bounds from the sun +you're interested in a situation where + + align:start position:0% +you're interested in a situation where + + + align:start position:0% +you're interested in a situation where +the energy of the axion is of order of + + align:start position:0% +the energy of the axion is of order of + + + align:start position:0% +the energy of the axion is of order of +the energy of the nucleons + + align:start position:0% +the energy of the nucleons + + + align:start position:0% +the energy of the nucleons +but the momentum of the axiom is much + + align:start position:0% +but the momentum of the axiom is much + + + align:start position:0% +but the momentum of the axiom is much +less so + + align:start position:0% +less so + + + align:start position:0% +less so +i'll call that k axion + + align:start position:0% +i'll call that k axion + + + align:start position:0% +i'll call that k axion +is much less than + + align:start position:0% +is much less than + + + align:start position:0% +is much less than +p nucleon + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so from a power counting perspective the + + align:start position:0% +so from a power counting perspective the + + + align:start position:0% +so from a power counting perspective the +energies are the same size but the + + align:start position:0% +energies are the same size but the + + + align:start position:0% +energies are the same size but the +momentum of the axion which is a + + align:start position:0% +momentum of the axion which is a + + + align:start position:0% +momentum of the axion which is a +relativistic particle and is complical + + align:start position:0% +relativistic particle and is complical + + + align:start position:0% +relativistic particle and is complical +to the energy + + align:start position:0% +to the energy + + + align:start position:0% +to the energy +is much less since the nucleon momentum + + align:start position:0% +is much less since the nucleon momentum + + + align:start position:0% +is much less since the nucleon momentum +is much bigger than its energy remember + + align:start position:0% +is much bigger than its energy remember + + + align:start position:0% +is much bigger than its energy remember +that the energy goes like p squared over + + align:start position:0% +that the energy goes like p squared over + + + align:start position:0% +that the energy goes like p squared over +m + + align:start position:0% +m + + + align:start position:0% +m +so the momentum are bigger + + align:start position:0% +so the momentum are bigger + + + align:start position:0% +so the momentum are bigger +and if that's the situation that you're + + align:start position:0% +and if that's the situation that you're + + + align:start position:0% +and if that's the situation that you're +in then when you're doing a lagrangian + + align:start position:0% +in then when you're doing a lagrangian + + + align:start position:0% +in then when you're doing a lagrangian +like this you have to be careful about + + align:start position:0% +like this you have to be careful about + + + align:start position:0% +like this you have to be careful about +implementing something like that + + align:start position:0% +implementing something like that + + + align:start position:0% +implementing something like that +and the way that it gets implemented is + + align:start position:0% +and the way that it gets implemented is + + + align:start position:0% +and the way that it gets implemented is +by a multiple expansion which we'll have + + align:start position:0% +by a multiple expansion which we'll have + + + align:start position:0% +by a multiple expansion which we'll have +opportunity to talk more about + + align:start position:0% +opportunity to talk more about + + + align:start position:0% +opportunity to talk more about +the near + + align:start position:0% +the near + + + align:start position:0% +the near +future but basically what it corresponds + + align:start position:0% +future but basically what it corresponds + + + align:start position:0% +future but basically what it corresponds +to is that you've got to make sure that + + align:start position:0% +to is that you've got to make sure that + + + align:start position:0% +to is that you've got to make sure that +you're not + + align:start position:0% +you're not + + + align:start position:0% +you're not +that you're sort of exchanging energy + + align:start position:0% +that you're sort of exchanging energy + + + align:start position:0% +that you're sort of exchanging energy +between these operators but not momenta + + align:start position:0% +between these operators but not momenta + + + align:start position:0% +between these operators but not momenta +that's what happens at lowest order so + + align:start position:0% +that's what happens at lowest order so + + + align:start position:0% +that's what happens at lowest order so +if you make this expansion in the + + align:start position:0% +if you make this expansion in the + + + align:start position:0% +if you make this expansion in the +lagrangian + + align:start position:0% +lagrangian + + + align:start position:0% +lagrangian +it corresponds to setting the spatial + + align:start position:0% +it corresponds to setting the spatial + + + align:start position:0% +it corresponds to setting the spatial +components of the axon field + + align:start position:0% +components of the axon field + + + align:start position:0% +components of the axon field +to zero + + align:start position:0% +to zero + + + align:start position:0% +to zero +okay so this is like doing a derivative + + align:start position:0% +okay so this is like doing a derivative + + + align:start position:0% +okay so this is like doing a derivative +doing an expansion around x vector + + align:start position:0% +doing an expansion around x vector + + + align:start position:0% +doing an expansion around x vector +equals zero and that + + align:start position:0% +equals zero and that + + + align:start position:0% +equals zero and that +the same thing in position space is this + + align:start position:0% +the same thing in position space is this + + + align:start position:0% +the same thing in position space is this +expansion here + + align:start position:0% + + + + align:start position:0% + +so this is + + align:start position:0% + + + + align:start position:0% + +implements + + align:start position:0% +implements + + + align:start position:0% +implements +the k much less than p + + align:start position:0% +the k much less than p + + + align:start position:0% +the k much less than p +expansion + + align:start position:0% + + + + align:start position:0% + +okay so that would actually be the + + align:start position:0% +okay so that would actually be the + + + align:start position:0% +okay so that would actually be the +operator that you would use to do a + + align:start position:0% +operator that you would use to do a + + + align:start position:0% +operator that you would use to do a +couple axons to nucleon + + align:start position:0% +couple axons to nucleon + + + align:start position:0% +couple axons to nucleon +now the interesting thing about this + + align:start position:0% +now the interesting thing about this + + + align:start position:0% +now the interesting thing about this +operator which ties into what we started + + align:start position:0% +operator which ties into what we started + + + align:start position:0% +operator which ties into what we started +talking about today + + align:start position:0% +talking about today + + + align:start position:0% +talking about today +is that once you take x equals zero the + + align:start position:0% +is that once you take x equals zero the + + + align:start position:0% +is that once you take x equals zero the +things that you're left with here + + align:start position:0% +things that you're left with here + + + align:start position:0% +things that you're left with here +are related to conserved charges of the + + align:start position:0% +are related to conserved charges of the + + + align:start position:0% +are related to conserved charges of the +su-4 symmetry + + align:start position:0% +su-4 symmetry + + + align:start position:0% +su-4 symmetry +so q-mu nu + + align:start position:0% +so q-mu nu + + + align:start position:0% +so q-mu nu +which is an integral overall space + + align:start position:0% +which is an integral overall space + + + align:start position:0% +which is an integral overall space +of n dagger + + align:start position:0% +of n dagger + + + align:start position:0% +of n dagger +sigma mu tau nu + + align:start position:0% +sigma mu tau nu + + + align:start position:0% +sigma mu tau nu +and + + align:start position:0% +and + + + align:start position:0% +and +that's the charge of su4 + + align:start position:0% + + + + align:start position:0% + +and the reason that it's that it's + + align:start position:0% +and the reason that it's that it's + + + align:start position:0% +and the reason that it's that it's +related to that is because once i take x + + align:start position:0% +related to that is because once i take x + + + align:start position:0% +related to that is because once i take x +equals zero here once i do the integral + + align:start position:0% +equals zero here once i do the integral + + + align:start position:0% +equals zero here once i do the integral +d4 x of the lagrangian the time this + + align:start position:0% +d4 x of the lagrangian the time this + + + align:start position:0% +d4 x of the lagrangian the time this +still depends on time but it doesn't + + align:start position:0% +still depends on time but it doesn't + + + align:start position:0% +still depends on time but it doesn't +depend on space so i can move the d3x + + align:start position:0% +depend on space so i can move the d3x + + + align:start position:0% +depend on space so i can move the d3x +through + + align:start position:0% +through + + + align:start position:0% +through +just let it act on this + + align:start position:0% +just let it act on this + + + align:start position:0% +just let it act on this +just let it act on that + + align:start position:0% +just let it act on that + + + align:start position:0% +just let it act on that +and then i get cumulu + + align:start position:0% +and then i get cumulu + + + align:start position:0% +and then i get cumulu +q0 j and q + + align:start position:0% +q0 j and q + + + align:start position:0% +q0 j and q +our q j 0 and q j 3. + + align:start position:0% +our q j 0 and q j 3. + + + align:start position:0% +our q j 0 and q j 3. +so this guy here + + align:start position:0% + + + + align:start position:0% + +color + + align:start position:0% + + + + align:start position:0% + +looks like + + align:start position:0% +looks like + + + align:start position:0% +looks like +qj3 + + align:start position:0% +qj3 + + + align:start position:0% +qj3 +qj0 + + align:start position:0% +qj0 + + + align:start position:0% +qj0 +let's go here + + align:start position:0% +let's go here + + + align:start position:0% +let's go here +j3 + + align:start position:0% +j3 + + + align:start position:0% +j3 +and that actually has non-trivial + + align:start position:0% +and that actually has non-trivial + + + align:start position:0% +and that actually has non-trivial +consequences + + align:start position:0% + + + + align:start position:0% + +because charges if they're charges of + + align:start position:0% +because charges if they're charges of + + + align:start position:0% +because charges if they're charges of +asymmetry + + align:start position:0% +asymmetry + + + align:start position:0% +asymmetry +are time independent + + align:start position:0% +are time independent + + + align:start position:0% +are time independent +so even though in principle + + align:start position:0% +so even though in principle + + + align:start position:0% +so even though in principle +i didn't make any assumptions + + align:start position:0% +i didn't make any assumptions + + + align:start position:0% +i didn't make any assumptions +about the time dependence here + + align:start position:0% +about the time dependence here + + + align:start position:0% +about the time dependence here +and these operators could exchange + + align:start position:0% +and these operators could exchange + + + align:start position:0% +and these operators could exchange +energy + + align:start position:0% + + + + align:start position:0% + +if i know that they're related to + + align:start position:0% +if i know that they're related to + + + align:start position:0% +if i know that they're related to +charges of the effect of the effective + + align:start position:0% +charges of the effect of the effective + + + align:start position:0% +charges of the effect of the effective +field theory then charges are conserved + + align:start position:0% +field theory then charges are conserved + + + align:start position:0% +field theory then charges are conserved +there's no time dependence + + align:start position:0% + + + + align:start position:0% + +so charges of the field theory + + align:start position:0% + + + + align:start position:0% + +are time independent + + align:start position:0% + + + + align:start position:0% + +and what that means then is that this + + align:start position:0% +and what that means then is that this + + + align:start position:0% +and what that means then is that this +is time independent and there's actually + + align:start position:0% +is time independent and there's actually + + + align:start position:0% +is time independent and there's actually +no energy exchange + + align:start position:0% +no energy exchange + + + align:start position:0% +no energy exchange +so the axion can only sort of exchange + + align:start position:0% +so the axion can only sort of exchange + + + align:start position:0% +so the axion can only sort of exchange +energy the only way the axon can couple + + align:start position:0% +energy the only way the axon can couple + + + align:start position:0% +energy the only way the axon can couple +is with zero energy + + align:start position:0% + + + + align:start position:0% + +and since it's derivatively coupled it + + align:start position:0% +and since it's derivatively coupled it + + + align:start position:0% +and since it's derivatively coupled it +has zero energy it has zero momentum and + + align:start position:0% +has zero energy it has zero momentum and + + + align:start position:0% +has zero energy it has zero momentum and +there's no coupling + + align:start position:0% +there's no coupling + + + align:start position:0% +there's no coupling +so in this limit + + align:start position:0% + + + + align:start position:0% + +that we talked about is a symmetry limit + + align:start position:0% +that we talked about is a symmetry limit + + + align:start position:0% +that we talked about is a symmetry limit +the axon just doesn't couple + + align:start position:0% + + + + align:start position:0% + +okay so there we're predicting something + + align:start position:0% +okay so there we're predicting something + + + align:start position:0% +okay so there we're predicting something +falling through kind of the consequences + + align:start position:0% +falling through kind of the consequences + + + align:start position:0% +falling through kind of the consequences +of symmetry + + align:start position:0% +of symmetry + + + align:start position:0% +of symmetry +on this effective field there predicting + + align:start position:0% +on this effective field there predicting + + + align:start position:0% +on this effective field there predicting +something about how axions coupled to + + align:start position:0% +something about how axions coupled to + + + align:start position:0% +something about how axions coupled to +the nucleons + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +if you look sort of through the possible + + align:start position:0% +if you look sort of through the possible + + + align:start position:0% +if you look sort of through the possible +processes + + align:start position:0% +processes + + + align:start position:0% +processes +that you could have + + align:start position:0% + + + + align:start position:0% + +you could have two nucleons in a 3s1 + + align:start position:0% +you could have two nucleons in a 3s1 + + + align:start position:0% +you could have two nucleons in a 3s1 +state + + align:start position:0% +state + + + align:start position:0% +state +try to produce an axion + + align:start position:0% +try to produce an axion + + + align:start position:0% +try to produce an axion +and + + align:start position:0% + + + + align:start position:0% + +that actually vanishes irrespective of + + align:start position:0% +that actually vanishes irrespective of + + + align:start position:0% +that actually vanishes irrespective of +the scattering lengths + + align:start position:0% +the scattering lengths + + + align:start position:0% +the scattering lengths +because you're coupling here to spin + + align:start position:0% +because you're coupling here to spin + + + align:start position:0% +because you're coupling here to spin +and that + + align:start position:0% +and that + + + align:start position:0% +and that +is always a good charge of the + + align:start position:0% +is always a good charge of the + + + align:start position:0% +is always a good charge of the +non-relativistic theory + + align:start position:0% + + + + align:start position:0% + +but there is a way that you could have + + align:start position:0% +but there is a way that you could have + + + align:start position:0% +but there is a way that you could have +the process go + + align:start position:0% + + + + align:start position:0% + +where you switch from a 1s0 state to a + + align:start position:0% +where you switch from a 1s0 state to a + + + align:start position:0% +where you switch from a 1s0 state to a +3s1 state + + align:start position:0% +3s1 state + + + align:start position:0% +3s1 state +and this guy vanishes if the scouting + + align:start position:0% +and this guy vanishes if the scouting + + + align:start position:0% +and this guy vanishes if the scouting +lengths go to infinity + + align:start position:0% + + + + align:start position:0% + +so if you ignored what i just said and + + align:start position:0% +so if you ignored what i just said and + + + align:start position:0% +so if you ignored what i just said and +you ignored this + + align:start position:0% +you ignored this + + + align:start position:0% +you ignored this +here and you just went ahead and + + align:start position:0% +here and you just went ahead and + + + align:start position:0% +here and you just went ahead and +calculated the finemen diagrams + + align:start position:0% +calculated the finemen diagrams + + + align:start position:0% +calculated the finemen diagrams +we would just find that the amplitude to + + align:start position:0% +we would just find that the amplitude to + + + align:start position:0% +we would just find that the amplitude to +this thing + + align:start position:0% +this thing + + + align:start position:0% +this thing +is proportional to this kind of factor + + align:start position:0% +is proportional to this kind of factor + + + align:start position:0% +is proportional to this kind of factor +that we saw before + + align:start position:0% + + + + align:start position:0% + +and since the scattering lengths are + + align:start position:0% +and since the scattering lengths are + + + align:start position:0% +and since the scattering lengths are +large it's vanishing if the scattering + + align:start position:0% +large it's vanishing if the scattering + + + align:start position:0% +large it's vanishing if the scattering +lines go to infinity + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so at lowest order the effective theory + + align:start position:0% +so at lowest order the effective theory + + + align:start position:0% +so at lowest order the effective theory +is suppressed this process and that has + + align:start position:0% +is suppressed this process and that has + + + align:start position:0% +is suppressed this process and that has +implications for of course the + + align:start position:0% +implications for of course the + + + align:start position:0% +implications for of course the +phenomenology you could also put in + + align:start position:0% +phenomenology you could also put in + + + align:start position:0% +phenomenology you could also put in +higher dimension operators like the c2s + + align:start position:0% +higher dimension operators like the c2s + + + align:start position:0% +higher dimension operators like the c2s +then of course you can get a + + align:start position:0% +then of course you can get a + + + align:start position:0% +then of course you can get a +contribution but that's higher order in + + align:start position:0% +contribution but that's higher order in + + + align:start position:0% +contribution but that's higher order in +the power counting and that affects how + + align:start position:0% +the power counting and that affects how + + + align:start position:0% +the power counting and that affects how +the axiom can be constrained in the sun + + align:start position:0% +the axiom can be constrained in the sun + + + align:start position:0% +the axiom can be constrained in the sun +okay so that gives you a little bit of + + align:start position:0% +okay so that gives you a little bit of + + + align:start position:0% +okay so that gives you a little bit of +feeling for what you can do with this + + align:start position:0% +feeling for what you can do with this + + + align:start position:0% +feeling for what you can do with this +effective field theory and how you can + + align:start position:0% +effective field theory and how you can + + + align:start position:0% +effective field theory and how you can +kind of + + align:start position:0% +kind of + + + align:start position:0% +kind of +exploit symmetry as well as the + + align:start position:0% +exploit symmetry as well as the + + + align:start position:0% +exploit symmetry as well as the +calculability of the effective theory to + + align:start position:0% +calculability of the effective theory to + + + align:start position:0% +calculability of the effective theory to +make lots of interesting predictions + + align:start position:0% +make lots of interesting predictions + + + align:start position:0% +make lots of interesting predictions +okay so any questions about that + + align:start position:0% + + + + align:start position:0% + +all right + + align:start position:0% +all right + + + align:start position:0% +all right +so + + align:start position:0% +so + + + align:start position:0% +so +uh that's all i have to say about that + + align:start position:0% +uh that's all i have to say about that + + + align:start position:0% +uh that's all i have to say about that +effective theory so we're now going to + + align:start position:0% +effective theory so we're now going to + + + align:start position:0% +effective theory so we're now going to +move on to our final effective field + + align:start position:0% +move on to our final effective field + + + align:start position:0% +move on to our final effective field +theory which is soft linear effective + + align:start position:0% +theory which is soft linear effective + + + align:start position:0% +theory which is soft linear effective +theory + + align:start position:0% + + + + align:start position:0% + +so what i intend to do with this part of + + align:start position:0% +so what i intend to do with this part of + + + align:start position:0% +so what i intend to do with this part of +the course which will take us through + + align:start position:0% +the course which will take us through + + + align:start position:0% +the course which will take us through +the rest of the year is i'm going to + + align:start position:0% +the rest of the year is i'm going to + + + align:start position:0% +the rest of the year is i'm going to +hand out lecture notes for you to read + + align:start position:0% +hand out lecture notes for you to read + + + align:start position:0% +hand out lecture notes for you to read +which i'm going to write + + align:start position:0% +which i'm going to write + + + align:start position:0% +which i'm going to write +so i haven't done that yet i'm going to + + align:start position:0% +so i haven't done that yet i'm going to + + + align:start position:0% +so i haven't done that yet i'm going to +continue to post + + align:start position:0% +continue to post + + + align:start position:0% +continue to post +i mean i have some rough copy of them + + align:start position:0% +i mean i have some rough copy of them + + + align:start position:0% +i mean i have some rough copy of them +but i'm going to make it pretty and + + align:start position:0% +but i'm going to make it pretty and + + + align:start position:0% +but i'm going to make it pretty and +beautiful for you or more beautiful than + + align:start position:0% +beautiful for you or more beautiful than + + + align:start position:0% +beautiful for you or more beautiful than +it currently is + + align:start position:0% +it currently is + + + align:start position:0% +it currently is +i'm also going to continue to post the + + align:start position:0% +i'm also going to continue to post the + + + align:start position:0% +i'm also going to continue to post the +lecture notes that i of what i present + + align:start position:0% +lecture notes that i of what i present + + + align:start position:0% +lecture notes that i of what i present +in lectures so you'll have sort of two + + align:start position:0% +in lectures so you'll have sort of two + + + align:start position:0% +in lectures so you'll have sort of two +versions of that you can read either the + + align:start position:0% +versions of that you can read either the + + + align:start position:0% +versions of that you can read either the +latex version or the handwritten version + + align:start position:0% +latex version or the handwritten version + + + align:start position:0% +latex version or the handwritten version +and depending on your taste you can + + align:start position:0% +and depending on your taste you can + + + align:start position:0% +and depending on your taste you can +look at one or the other + + align:start position:0% +look at one or the other + + + align:start position:0% +look at one or the other +so what we'll do today is we'll just + + align:start position:0% +so what we'll do today is we'll just + + + align:start position:0% +so what we'll do today is we'll just +sort of briefly introduce ourselves to + + align:start position:0% +sort of briefly introduce ourselves to + + + align:start position:0% +sort of briefly introduce ourselves to +this effective theory + + align:start position:0% + + + + align:start position:0% + +and by way of introduction to any + + align:start position:0% +and by way of introduction to any + + + align:start position:0% +and by way of introduction to any +effective theory the kind of things that + + align:start position:0% +effective theory the kind of things that + + + align:start position:0% +effective theory the kind of things that +we should talk about are y + + align:start position:0% +we should talk about are y + + + align:start position:0% +we should talk about are y +so we'll talk about why + + align:start position:0% +so we'll talk about why + + + align:start position:0% +so we'll talk about why +then we should talk about what the + + align:start position:0% +then we should talk about what the + + + align:start position:0% +then we should talk about what the +degrees of freedom are + + align:start position:0% + + + + align:start position:0% + +and in this case we'll also talk about + + align:start position:0% +and in this case we'll also talk about + + + align:start position:0% +and in this case we'll also talk about +kind of what are convenient coordinates + + align:start position:0% +kind of what are convenient coordinates + + + align:start position:0% +kind of what are convenient coordinates +to be using for this effective theory + + align:start position:0% +to be using for this effective theory + + + align:start position:0% +to be using for this effective theory +so that's where we'll + + align:start position:0% + + + + align:start position:0% + +but we'll start covering today + + align:start position:0% +but we'll start covering today + + + align:start position:0% +but we'll start covering today +so what is sct + + align:start position:0% + + + + align:start position:0% + +so it's an effective field theory that + + align:start position:0% +so it's an effective field theory that + + + align:start position:0% +so it's an effective field theory that +you can use for multiple things + + align:start position:0% +you can use for multiple things + + + align:start position:0% +you can use for multiple things +one is for + + align:start position:0% +one is for + + + align:start position:0% +one is for +energetic hadrons + + align:start position:0% + + + + align:start position:0% + +so the energy of the hadron should be + + align:start position:0% +so the energy of the hadron should be + + + align:start position:0% +so the energy of the hadron should be +something that's a large scale which + + align:start position:0% +something that's a large scale which + + + align:start position:0% +something that's a large scale which +i'll call q + + align:start position:0% +i'll call q + + + align:start position:0% +i'll call q +conventional notation + + align:start position:0% +conventional notation + + + align:start position:0% +conventional notation +and by energetic it means much more + + align:start position:0% +and by energetic it means much more + + + align:start position:0% +and by energetic it means much more +energetic than the mass of the hadrons + + align:start position:0% +energetic than the mass of the hadrons + + + align:start position:0% +energetic than the mass of the hadrons +which is the water + + align:start position:0% +which is the water + + + align:start position:0% +which is the water +lambda qcd + + align:start position:0% + + + + align:start position:0% + +it's also an effective theory for + + align:start position:0% +it's also an effective theory for + + + align:start position:0% +it's also an effective theory for +energetic jets + + align:start position:0% + + + + align:start position:0% + +and the situation is in some ways + + align:start position:0% +and the situation is in some ways + + + align:start position:0% +and the situation is in some ways +similar to the hadrons + + align:start position:0% +similar to the hadrons + + + align:start position:0% +similar to the hadrons +you have a jet energy that's large of + + align:start position:0% +you have a jet energy that's large of + + + align:start position:0% +you have a jet energy that's large of +order some q and that's much bigger than + + align:start position:0% +order some q and that's much bigger than + + + align:start position:0% +order some q and that's much bigger than +the jet mass which + + align:start position:0% + + + + align:start position:0% + +is a root squared of some form momentum + + align:start position:0% + + + + align:start position:0% + +and by the name you should also imagine + + align:start position:0% +and by the name you should also imagine + + + align:start position:0% +and by the name you should also imagine +that really what it is is something to + + align:start position:0% +that really what it is is something to + + + align:start position:0% +that really what it is is something to +do with qcd + + align:start position:0% + + + + align:start position:0% + +well maybe not not by the name but + + align:start position:0% + + + + align:start position:0% + +it is something to do with qcd + + align:start position:0% +it is something to do with qcd + + + align:start position:0% +it is something to do with qcd +and it's kind of what you get if you + + align:start position:0% +and it's kind of what you get if you + + + align:start position:0% +and it's kind of what you get if you +start with qcd and you focus your + + align:start position:0% +start with qcd and you focus your + + + align:start position:0% +start with qcd and you focus your +attention + + align:start position:0% +attention + + + align:start position:0% +attention +on a certain set of interactions + + align:start position:0% +on a certain set of interactions + + + align:start position:0% +on a certain set of interactions +which are collinear and soft + + align:start position:0% +which are collinear and soft + + + align:start position:0% +which are collinear and soft +interactions + + align:start position:0% + + + + align:start position:0% + +so we've met several different examples + + align:start position:0% +so we've met several different examples + + + align:start position:0% +so we've met several different examples +of effective field theories so far in + + align:start position:0% +of effective field theories so far in + + + align:start position:0% +of effective field theories so far in +the course some of them were bottom-up + + align:start position:0% +the course some of them were bottom-up + + + align:start position:0% +the course some of them were bottom-up +some of them were top down this is going + + align:start position:0% +some of them were top down this is going + + + align:start position:0% +some of them were top down this is going +to be a top-down effective field theory + + align:start position:0% +to be a top-down effective field theory + + + align:start position:0% +to be a top-down effective field theory +just like hqet was a top-down effective + + align:start position:0% +just like hqet was a top-down effective + + + align:start position:0% +just like hqet was a top-down effective +field theory + + align:start position:0% +field theory + + + align:start position:0% +field theory +so we'll be able to start with the qcd + + align:start position:0% +so we'll be able to start with the qcd + + + align:start position:0% +so we'll be able to start with the qcd +lagrangian and derive this theory by + + align:start position:0% +lagrangian and derive this theory by + + + align:start position:0% +lagrangian and derive this theory by +taking certain limits and that's what + + align:start position:0% +taking certain limits and that's what + + + align:start position:0% +taking certain limits and that's what +we'll do + + align:start position:0% + + + + align:start position:0% + +so why why study this i will come to + + align:start position:0% +so why why study this i will come to + + + align:start position:0% +so why why study this i will come to +that in a bit but + + align:start position:0% +that in a bit but + + + align:start position:0% +that in a bit but +what are the kind of features of this + + align:start position:0% +what are the kind of features of this + + + align:start position:0% +what are the kind of features of this +from an effective field theory point of + + align:start position:0% +from an effective field theory point of + + + align:start position:0% +from an effective field theory point of +view that make it interesting + + align:start position:0% + + + + align:start position:0% + +we'll talk about the answer to both + + align:start position:0% +we'll talk about the answer to both + + + align:start position:0% +we'll talk about the answer to both +those questions + + align:start position:0% + + + + align:start position:0% + +so first + + align:start position:0% +so first + + + align:start position:0% +so first +why + + align:start position:0% +why + + + align:start position:0% +why +study this + + align:start position:0% + + + + align:start position:0% + +what's this effective theory good for + + align:start position:0% +what's this effective theory good for + + + align:start position:0% +what's this effective theory good for +so one thing it's good for is + + align:start position:0% +so one thing it's good for is + + + align:start position:0% +so one thing it's good for is +understanding factorization + + align:start position:0% + + + + align:start position:0% + +and if you think about what we're doing + + align:start position:0% +and if you think about what we're doing + + + align:start position:0% +and if you think about what we're doing +when we probe for short distance physics + + align:start position:0% +when we probe for short distance physics + + + align:start position:0% +when we probe for short distance physics +say at the lhc + + align:start position:0% +say at the lhc + + + align:start position:0% +say at the lhc +we're probing for short distance physics + + align:start position:0% +we're probing for short distance physics + + + align:start position:0% +we're probing for short distance physics +by colliding things at high energy + + align:start position:0% + + + + align:start position:0% + +so we're carrying out hard collisions + + align:start position:0% + + + + align:start position:0% + +energetic collisions of particles + + align:start position:0% +energetic collisions of particles + + + align:start position:0% +energetic collisions of particles +so the fact that this effective field + + align:start position:0% +so the fact that this effective field + + + align:start position:0% +so the fact that this effective field +theory deals with energetic particles + + align:start position:0% +theory deals with energetic particles + + + align:start position:0% +theory deals with energetic particles +may + + align:start position:0% +may + + + align:start position:0% +may +ring a bell as being something useful + + align:start position:0% +ring a bell as being something useful + + + align:start position:0% +ring a bell as being something useful +for understanding short distance physics + + align:start position:0% + + + + align:start position:0% + +and so what this effective theory allows + + align:start position:0% +and so what this effective theory allows + + + align:start position:0% +and so what this effective theory allows +you to do is disentangle the short + + align:start position:0% +you to do is disentangle the short + + + align:start position:0% +you to do is disentangle the short +distance physics that you're interested + + align:start position:0% +distance physics that you're interested + + + align:start position:0% +distance physics that you're interested +in + + align:start position:0% +in + + + align:start position:0% +in +from the longer distance physics that's + + align:start position:0% +from the longer distance physics that's + + + align:start position:0% +from the longer distance physics that's +associated to winding together into + + align:start position:0% +associated to winding together into + + + align:start position:0% +associated to winding together into +hadrons or producing these energetic + + align:start position:0% +hadrons or producing these energetic + + + align:start position:0% +hadrons or producing these energetic +dots + + align:start position:0% +dots + + + align:start position:0% +dots +so it's really disentangling the long + + align:start position:0% +so it's really disentangling the long + + + align:start position:0% +so it's really disentangling the long +and short distance physics + + align:start position:0% +and short distance physics + + + align:start position:0% +and short distance physics +in the standard model or the standard + + align:start position:0% +in the standard model or the standard + + + align:start position:0% +in the standard model or the standard +model plus new physics + + align:start position:0% +model plus new physics + + + align:start position:0% +model plus new physics +and basically what that amounts to is + + align:start position:0% +and basically what that amounts to is + + + align:start position:0% +and basically what that amounts to is +disentangling long and short distance + + align:start position:0% +disentangling long and short distance + + + align:start position:0% +disentangling long and short distance +physics in qcd + + align:start position:0% + + + + align:start position:0% + +so let me write it this way + + align:start position:0% +so let me write it this way + + + align:start position:0% +so let me write it this way +disentangling the physics of qcd with + + align:start position:0% +disentangling the physics of qcd with + + + align:start position:0% +disentangling the physics of qcd with +addition electroweak or bsm + + align:start position:0% + + + + align:start position:0% + +physics requires a separation of scales + + align:start position:0% + + + + align:start position:0% + +we have to decide what's short distance + + align:start position:0% +we have to decide what's short distance + + + align:start position:0% +we have to decide what's short distance +what's long distance + + align:start position:0% + + + + align:start position:0% + +if we're interested in a process like + + align:start position:0% +if we're interested in a process like + + + align:start position:0% +if we're interested in a process like +the lhc where we're colliding together + + align:start position:0% +the lhc where we're colliding together + + + align:start position:0% +the lhc where we're colliding together +hadrons then that's of course + + align:start position:0% +hadrons then that's of course + + + align:start position:0% +hadrons then that's of course +absolutely necessary + + align:start position:0% +absolutely necessary + + + align:start position:0% +absolutely necessary +because the hadrons are long distance + + align:start position:0% +because the hadrons are long distance + + + align:start position:0% +because the hadrons are long distance +things and we're interested in short + + align:start position:0% +things and we're interested in short + + + align:start position:0% +things and we're interested in short +distance physics + + align:start position:0% +distance physics + + + align:start position:0% +distance physics +and we can do that with sct + + align:start position:0% +and we can do that with sct + + + align:start position:0% +and we can do that with sct +that's perhaps the biggest motivation + + align:start position:0% +that's perhaps the biggest motivation + + + align:start position:0% +that's perhaps the biggest motivation +for us today + + align:start position:0% + + + + align:start position:0% + +when we make hard collisions these jets + + align:start position:0% +when we make hard collisions these jets + + + align:start position:0% +when we make hard collisions these jets +and energetic hadrons are very common + + align:start position:0% +and energetic hadrons are very common + + + align:start position:0% +and energetic hadrons are very common +they're the most common things that are + + align:start position:0% +they're the most common things that are + + + align:start position:0% +they're the most common things that are +produced + + align:start position:0% +produced + + + align:start position:0% +produced +and from a physics point of view that + + align:start position:0% +and from a physics point of view that + + + align:start position:0% +and from a physics point of view that +means that there's many many different + + align:start position:0% +means that there's many many different + + + align:start position:0% +means that there's many many different +processes that you can actually use this + + align:start position:0% +processes that you can actually use this + + + align:start position:0% +processes that you can actually use this +effective field theory for and that's + + align:start position:0% +effective field theory for and that's + + + align:start position:0% +effective field theory for and that's +one of the reasons it's popular + + align:start position:0% +one of the reasons it's popular + + + align:start position:0% +one of the reasons it's popular +so + + align:start position:0% +so + + + align:start position:0% +so +let me give you some examples + + align:start position:0% + + + + align:start position:0% + +you could do deep inelastic scattering + + align:start position:0% +you could do deep inelastic scattering + + + align:start position:0% +you could do deep inelastic scattering +with this effective theory deep in + + align:start position:0% +with this effective theory deep in + + + align:start position:0% +with this effective theory deep in +elastic scattering involves a hard + + align:start position:0% +elastic scattering involves a hard + + + align:start position:0% +elastic scattering involves a hard +collision + + align:start position:0% + + + + align:start position:0% + +and even class classic textbook deep + + align:start position:0% +and even class classic textbook deep + + + align:start position:0% +and even class classic textbook deep +inelastic scattering is made very much + + align:start position:0% +inelastic scattering is made very much + + + align:start position:0% +inelastic scattering is made very much +simpler by this effective field theory + + align:start position:0% +simpler by this effective field theory + + + align:start position:0% +simpler by this effective field theory +and we'll + + align:start position:0% +and we'll + + + align:start position:0% +and we'll +show you that example is one of our + + align:start position:0% +show you that example is one of our + + + align:start position:0% +show you that example is one of our +examples later + + align:start position:0% + + + + align:start position:0% + +on you could do dualian with + + align:start position:0% +on you could do dualian with + + + align:start position:0% +on you could do dualian with +either protons and antiprotons or + + align:start position:0% +either protons and antiprotons or + + + align:start position:0% +either protons and antiprotons or +protons and protons + + align:start position:0% +protons and protons + + + align:start position:0% +protons and protons +you could do + + align:start position:0% +you could do + + + align:start position:0% +you could do +higgs production + + align:start position:0% +higgs production + + + align:start position:0% +higgs production +and people use this effective field + + align:start position:0% +and people use this effective field + + + align:start position:0% +and people use this effective field +theory to study higgs production + + align:start position:0% +theory to study higgs production + + + align:start position:0% +theory to study higgs production +at the lhc + + align:start position:0% +at the lhc + + + align:start position:0% +at the lhc +you could do it by way of trying to make + + align:start position:0% +you could do it by way of trying to make + + + align:start position:0% +you could do it by way of trying to make +the examples more varied + + align:start position:0% +the examples more varied + + + align:start position:0% +the examples more varied +e plus e minus two jets this is another + + align:start position:0% +e plus e minus two jets this is another + + + align:start position:0% +e plus e minus two jets this is another +thing that the effective theory is used + + align:start position:0% +thing that the effective theory is used + + + align:start position:0% +thing that the effective theory is used +for + + align:start position:0% +for + + + align:start position:0% +for +you could do quarkonia physics e plus + + align:start position:0% +you could do quarkonia physics e plus + + + align:start position:0% +you could do quarkonia physics e plus +and minus producing a j psi and an x + + align:start position:0% +and minus producing a j psi and an x + + + align:start position:0% +and minus producing a j psi and an x +uh here you need a combination if the + + align:start position:0% +uh here you need a combination if the + + + align:start position:0% +uh here you need a combination if the +json is produced at large energy of kind + + align:start position:0% +json is produced at large energy of kind + + + align:start position:0% +json is produced at large energy of kind +of a non-relativistic qcd for this cc + + align:start position:0% +of a non-relativistic qcd for this cc + + + align:start position:0% +of a non-relativistic qcd for this cc +bar bound state + + align:start position:0% +bar bound state + + + align:start position:0% +bar bound state +as well as an sct for the fact that it's + + align:start position:0% +as well as an sct for the fact that it's + + + align:start position:0% +as well as an sct for the fact that it's +a energetic state + + align:start position:0% +a energetic state + + + align:start position:0% +a energetic state +so this would be actually a combination + + align:start position:0% +so this would be actually a combination + + + align:start position:0% +so this would be actually a combination +of two different effective field + + align:start position:0% +of two different effective field + + + align:start position:0% +of two different effective field +theories + + align:start position:0% +theories + + + align:start position:0% +theories +people + + align:start position:0% +people + + + align:start position:0% +people +use it for thinking about jet + + align:start position:0% +use it for thinking about jet + + + align:start position:0% +use it for thinking about jet +substructure + + align:start position:0% +substructure + + + align:start position:0% +substructure +so all sorts of things that you might be + + align:start position:0% +so all sorts of things that you might be + + + align:start position:0% +so all sorts of things that you might be +interested in and thinking about having + + align:start position:0% +interested in and thinking about having + + + align:start position:0% +interested in and thinking about having +to do with hard scattering + + align:start position:0% + + + + align:start position:0% + +there's also another way that you could + + align:start position:0% +there's also another way that you could + + + align:start position:0% +there's also another way that you could +get + + align:start position:0% +get + + + align:start position:0% +get +energetic particles even if you don't + + align:start position:0% +energetic particles even if you don't + + + align:start position:0% +energetic particles even if you don't +force them to be energetic and that is + + align:start position:0% +force them to be energetic and that is + + + align:start position:0% +force them to be energetic and that is +if you had a very heavy particle + + align:start position:0% +if you had a very heavy particle + + + align:start position:0% +if you had a very heavy particle +decaying + + align:start position:0% + + + + align:start position:0% + +so if you had a beam as on decaying and + + align:start position:0% +so if you had a beam as on decaying and + + + align:start position:0% +so if you had a beam as on decaying and +it decayed to light stuff + + align:start position:0% +it decayed to light stuff + + + align:start position:0% +it decayed to light stuff +this would also be the right effective + + align:start position:0% +this would also be the right effective + + + align:start position:0% +this would also be the right effective +theory for that + + align:start position:0% +theory for that + + + align:start position:0% +theory for that +so for example in the process bds gamma + + align:start position:0% +so for example in the process bds gamma + + + align:start position:0% +so for example in the process bds gamma +this effective theory plays a role + + align:start position:0% +this effective theory plays a role + + + align:start position:0% +this effective theory plays a role +in the process b to d pi where the pion + + align:start position:0% +in the process b to d pi where the pion + + + align:start position:0% +in the process b to d pi where the pion +comes out very energetic + + align:start position:0% +comes out very energetic + + + align:start position:0% +comes out very energetic +or b to pi pi which is something very + + align:start position:0% +or b to pi pi which is something very + + + align:start position:0% +or b to pi pi which is something very +interesting for studying cp violation + + align:start position:0% +interesting for studying cp violation + + + align:start position:0% +interesting for studying cp violation +you can use this effective theory to + + align:start position:0% +you can use this effective theory to + + + align:start position:0% +you can use this effective theory to +understand the short and long distance + + align:start position:0% +understand the short and long distance + + + align:start position:0% +understand the short and long distance +physics in those processes as well + + align:start position:0% +physics in those processes as well + + + align:start position:0% +physics in those processes as well +okay and this is coming about because + + align:start position:0% +okay and this is coming about because + + + align:start position:0% +okay and this is coming about because +this b meson is heavy + + align:start position:0% + + + + align:start position:0% + +so that's a sort of range of + + align:start position:0% +so that's a sort of range of + + + align:start position:0% +so that's a sort of range of +examples and it's really not really + + align:start position:0% +examples and it's really not really + + + align:start position:0% +examples and it's really not really +complete in any sense there's just lots + + align:start position:0% +complete in any sense there's just lots + + + align:start position:0% +complete in any sense there's just lots +of different things you can + + align:start position:0% +of different things you can + + + align:start position:0% +of different things you can +study with this theory + + align:start position:0% + + + + align:start position:0% + +so this i already said let me write it + + align:start position:0% + + + + align:start position:0% + +i sort of alluded to separating + + align:start position:0% +i sort of alluded to separating + + + align:start position:0% +i sort of alluded to separating +perturbative physics + + align:start position:0% +perturbative physics + + + align:start position:0% +perturbative physics +at short distances + + align:start position:0% +at short distances + + + align:start position:0% +at short distances +from the non-perturbative physics + + align:start position:0% +from the non-perturbative physics + + + align:start position:0% +from the non-perturbative physics +at long distances + + align:start position:0% + + + + align:start position:0% + +and the non-protective physics if you're + + align:start position:0% +and the non-protective physics if you're + + + align:start position:0% +and the non-protective physics if you're +lucky maybe only encoded in part-time + + align:start position:0% +lucky maybe only encoded in part-time + + + align:start position:0% +lucky maybe only encoded in part-time +distribution functions or something if + + align:start position:0% +distribution functions or something if + + + align:start position:0% +distribution functions or something if +you're doing a pp collision + + align:start position:0% +you're doing a pp collision + + + align:start position:0% +you're doing a pp collision +and you'd like to separate that from + + align:start position:0% +and you'd like to separate that from + + + align:start position:0% +and you'd like to separate that from +shorter distance physics that you can + + align:start position:0% +shorter distance physics that you can + + + align:start position:0% +shorter distance physics that you can +calculate perturbatively and this is a + + align:start position:0% +calculate perturbatively and this is a + + + align:start position:0% +calculate perturbatively and this is a +way of doing that + + align:start position:0% + + + + align:start position:0% + +and then + + align:start position:0% +and then + + + align:start position:0% +and then +there's our normalization group in this + + align:start position:0% +there's our normalization group in this + + + align:start position:0% +there's our normalization group in this +effective theory + + align:start position:0% +effective theory + + + align:start position:0% +effective theory +and that normalization group actually + + align:start position:0% +and that normalization group actually + + + align:start position:0% +and that normalization group actually +allows you to do something cool too + + align:start position:0% +allows you to do something cool too + + + align:start position:0% +allows you to do something cool too +and that is that you can sum up + + align:start position:0% +and that is that you can sum up + + + align:start position:0% +and that is that you can sum up +something called + + align:start position:0% +something called + + + align:start position:0% +something called +sudikov logarithms which are logarithms + + align:start position:0% +sudikov logarithms which are logarithms + + + align:start position:0% +sudikov logarithms which are logarithms +that + + align:start position:0% +that + + + align:start position:0% +that +are appearing in our canonical way as + + align:start position:0% +are appearing in our canonical way as + + + align:start position:0% +are appearing in our canonical way as +alpha s times a logarithm + + align:start position:0% +alpha s times a logarithm + + + align:start position:0% +alpha s times a logarithm +but instead of one logarithm you + + align:start position:0% +but instead of one logarithm you + + + align:start position:0% +but instead of one logarithm you +actually get two + + align:start position:0% +actually get two + + + align:start position:0% +actually get two +and so the normalization group in this + + align:start position:0% +and so the normalization group in this + + + align:start position:0% +and so the normalization group in this +effective theory will allow you to + + align:start position:0% +effective theory will allow you to + + + align:start position:0% +effective theory will allow you to +handle those pseudocop logarithms + + align:start position:0% +handle those pseudocop logarithms + + + align:start position:0% +handle those pseudocop logarithms +okay so that's some set of things + + align:start position:0% + + + + align:start position:0% + +what are we going to have to do that we + + align:start position:0% +what are we going to have to do that we + + + align:start position:0% +what are we going to have to do that we +haven't done before what are the kind of + + align:start position:0% +haven't done before what are the kind of + + + align:start position:0% +haven't done before what are the kind of +new + + align:start position:0% +new + + + align:start position:0% +new +ingredients that we're going to run into + + align:start position:0% +ingredients that we're going to run into + + + align:start position:0% +ingredients that we're going to run into +so sort of a prelude to things to come + + align:start position:0% + + + + align:start position:0% + +or another way of saying what makes sct + + align:start position:0% +or another way of saying what makes sct + + + align:start position:0% +or another way of saying what makes sct +different from the effective theories + + align:start position:0% +different from the effective theories + + + align:start position:0% +different from the effective theories +we've seen so far + + align:start position:0% + + + + align:start position:0% + +let's have a little list for that as + + align:start position:0% +let's have a little list for that as + + + align:start position:0% +let's have a little list for that as +well + + align:start position:0% +well + + + align:start position:0% +well +so perhaps the most uh interesting one + + align:start position:0% +so perhaps the most uh interesting one + + + align:start position:0% +so perhaps the most uh interesting one +is that we are going to have + + align:start position:0% +is that we are going to have + + + align:start position:0% +is that we are going to have +more than one field + + align:start position:0% +more than one field + + + align:start position:0% +more than one field +for + + align:start position:0% +for + + + align:start position:0% +for +each degree of freedom + + align:start position:0% + + + + align:start position:0% + +so we're going to have more than one + + align:start position:0% +so we're going to have more than one + + + align:start position:0% +so we're going to have more than one +field + + align:start position:0% +field + + + align:start position:0% +field +that's not quite the right way of saying + + align:start position:0% +that's not quite the right way of saying + + + align:start position:0% +that's not quite the right way of saying +it we're going to have more than one + + align:start position:0% +it we're going to have more than one + + + align:start position:0% +it we're going to have more than one +field for the same particle + + align:start position:0% + + + + align:start position:0% + +it's a slightly different statement + + align:start position:0% + + + + align:start position:0% + +so we're going to have a field + + align:start position:0% + + + + align:start position:0% + +which we'll talk about + + align:start position:0% +which we'll talk about + + + align:start position:0% +which we'll talk about +that i'll call c sub n which is a linear + + align:start position:0% +that i'll call c sub n which is a linear + + + align:start position:0% +that i'll call c sub n which is a linear +cork field + + align:start position:0% + + + + align:start position:0% + +for some quark say an up quark + + align:start position:0% +for some quark say an up quark + + + align:start position:0% +for some quark say an up quark +and there's also going to be another + + align:start position:0% +and there's also going to be another + + + align:start position:0% +and there's also going to be another +field q sub s + + align:start position:0% +field q sub s + + + align:start position:0% +field q sub s +which is a soft cork field for the same + + align:start position:0% +which is a soft cork field for the same + + + align:start position:0% +which is a soft cork field for the same +up quark + + align:start position:0% + + + + align:start position:0% + +so let's say for the up quark say just + + align:start position:0% +so let's say for the up quark say just + + + align:start position:0% +so let's say for the up quark say just +to make it definite + + align:start position:0% + + + + align:start position:0% + +and the reason that we're going to have + + align:start position:0% +and the reason that we're going to have + + + align:start position:0% +and the reason that we're going to have +these two different fields is because + + align:start position:0% +these two different fields is because + + + align:start position:0% +these two different fields is because +they're going to describe the same + + align:start position:0% +they're going to describe the same + + + align:start position:0% +they're going to describe the same +particle but in different regions of + + align:start position:0% +particle but in different regions of + + + align:start position:0% +particle but in different regions of +momentum space + + align:start position:0% +momentum space + + + align:start position:0% +momentum space +so if you're like they're describing + + align:start position:0% +so if you're like they're describing + + + align:start position:0% +so if you're like they're describing +different degrees of freedom of the same + + align:start position:0% +different degrees of freedom of the same + + + align:start position:0% +different degrees of freedom of the same +particle because they're in different + + align:start position:0% +particle because they're in different + + + align:start position:0% +particle because they're in different +regions of momentum space but it still + + align:start position:0% +regions of momentum space but it still + + + align:start position:0% +regions of momentum space but it still +is the same particle and that's not + + align:start position:0% +is the same particle and that's not + + + align:start position:0% +is the same particle and that's not +something we've had to deal with + + align:start position:0% +something we've had to deal with + + + align:start position:0% +something we've had to deal with +in any of our examples so far we always + + align:start position:0% +in any of our examples so far we always + + + align:start position:0% +in any of our examples so far we always +had one field for each particle now + + align:start position:0% +had one field for each particle now + + + align:start position:0% +had one field for each particle now +we're going to have more than one + + align:start position:0% +we're going to have more than one + + + align:start position:0% +we're going to have more than one +so that's one complication + + align:start position:0% + + + + align:start position:0% + +this second one we have actually + + align:start position:0% +this second one we have actually + + + align:start position:0% +this second one we have actually +encountered before + + align:start position:0% +encountered before + + + align:start position:0% +encountered before +and that is that we're going to + + align:start position:0% +and that is that we're going to + + + align:start position:0% +and that is that we're going to +integrate out + + align:start position:0% +integrate out + + + align:start position:0% +integrate out +off shell modes + + align:start position:0% + + + + align:start position:0% + +of a field + + align:start position:0% +of a field + + + align:start position:0% +of a field +but not the entire + + align:start position:0% +but not the entire + + + align:start position:0% +but not the entire +not the entire + + align:start position:0% +not the entire + + + align:start position:0% +not the entire +particle + + align:start position:0% + + + + align:start position:0% + +not the entire degree of freedom + + align:start position:0% + + + + align:start position:0% + +and we encountered that when we talked + + align:start position:0% +and we encountered that when we talked + + + align:start position:0% +and we encountered that when we talked +about hqt + + align:start position:0% +about hqt + + + align:start position:0% +about hqt +so + + align:start position:0% +so + + + align:start position:0% +so +the situation here will be a little more + + align:start position:0% +the situation here will be a little more + + + align:start position:0% +the situation here will be a little more +complicated than hqet but + + align:start position:0% +complicated than hqet but + + + align:start position:0% +complicated than hqet but +this second point is like hqet and we'll + + align:start position:0% +this second point is like hqet and we'll + + + align:start position:0% +this second point is like hqet and we'll +use some of our experience that + + align:start position:0% +use some of our experience that + + + align:start position:0% +use some of our experience that +we gained from studying hqt + + align:start position:0% + + + + align:start position:0% + +which one it never can be + + align:start position:0% +which one it never can be + + + align:start position:0% +which one it never can be +right both + + align:start position:0% +right both + + + align:start position:0% +right both +it will have to decide whether it's one + + align:start position:0% +it will have to decide whether it's one + + + align:start position:0% +it will have to decide whether it's one +or the other + + align:start position:0% +or the other + + + align:start position:0% +or the other +so an important thing + + align:start position:0% +so an important thing + + + align:start position:0% +so an important thing +exactly this issue of which which is it + + align:start position:0% +exactly this issue of which which is it + + + align:start position:0% +exactly this issue of which which is it +is an important thing because you you're + + align:start position:0% +is an important thing because you you're + + + align:start position:0% +is an important thing because you you're +going to be describing with these fields + + align:start position:0% +going to be describing with these fields + + + align:start position:0% +going to be describing with these fields +certain fluctuations and you don't want + + align:start position:0% +certain fluctuations and you don't want + + + align:start position:0% +certain fluctuations and you don't want +overlap + + align:start position:0% +overlap + + + align:start position:0% +overlap +so you're going to have to if you point + + align:start position:0% +so you're going to have to if you point + + + align:start position:0% +so you're going to have to if you point +your finger somewhere in momentum space + + align:start position:0% +your finger somewhere in momentum space + + + align:start position:0% +your finger somewhere in momentum space +we'll have to decide is it in this + + align:start position:0% +we'll have to decide is it in this + + + align:start position:0% +we'll have to decide is it in this +category this category it can't be in + + align:start position:0% +category this category it can't be in + + + align:start position:0% +category this category it can't be in +both + + align:start position:0% +both + + + align:start position:0% +both +but that will be important that that + + align:start position:0% +but that will be important that that + + + align:start position:0% +but that will be important that that +will come back + + align:start position:0% + + + + align:start position:0% + +two regions + + align:start position:0% +two regions + + + align:start position:0% +two regions +and no overlap + + align:start position:0% +and no overlap + + + align:start position:0% +and no overlap +but we'll have to work a little bit to + + align:start position:0% +but we'll have to work a little bit to + + + align:start position:0% +but we'll have to work a little bit to +make sure that's true + + align:start position:0% + + + + align:start position:0% + +yeah we don't want to make sure to not + + align:start position:0% +yeah we don't want to make sure to not + + + align:start position:0% +yeah we don't want to make sure to not +have double counting in the effective + + align:start position:0% +have double counting in the effective + + + align:start position:0% +have double counting in the effective +theory where you know we could write + + align:start position:0% +theory where you know we could write + + + align:start position:0% +theory where you know we could write +down something + + align:start position:0% +down something + + + align:start position:0% +down something +that + + align:start position:0% +that + + + align:start position:0% +that +looks like it could be described by + + align:start position:0% +looks like it could be described by + + + align:start position:0% +looks like it could be described by +either one and if that was true then we + + align:start position:0% +either one and if that was true then we + + + align:start position:0% +either one and if that was true then we +would be have a problem + + align:start position:0% + + + + align:start position:0% + +so another thing that makes sct + + align:start position:0% +so another thing that makes sct + + + align:start position:0% +so another thing that makes sct +interesting from a + + align:start position:0% +interesting from a + + + align:start position:0% +interesting from a +eft point of view is that we have + + align:start position:0% +eft point of view is that we have + + + align:start position:0% +eft point of view is that we have +convolutions + + align:start position:0% +convolutions + + + align:start position:0% +convolutions +so + + align:start position:0% +so + + + align:start position:0% +so +usually in an effective theory you think + + align:start position:0% +usually in an effective theory you think + + + align:start position:0% +usually in an effective theory you think +about having multiple operators that + + align:start position:0% +about having multiple operators that + + + align:start position:0% +about having multiple operators that +have + + align:start position:0% +have + + + align:start position:0% +have +same quantum numbers we sum over those + + align:start position:0% +same quantum numbers we sum over those + + + align:start position:0% +same quantum numbers we sum over those +operators say some order in the power + + align:start position:0% +operators say some order in the power + + + align:start position:0% +operators say some order in the power +counting + + align:start position:0% +counting + + + align:start position:0% +counting +some over i of wilson coefficients times + + align:start position:0% +some over i of wilson coefficients times + + + align:start position:0% +some over i of wilson coefficients times +operators + + align:start position:0% +operators + + + align:start position:0% +operators +and this sum becomes a continuous + + align:start position:0% +and this sum becomes a continuous + + + align:start position:0% +and this sum becomes a continuous +integral in the + + align:start position:0% +integral in the + + + align:start position:0% +integral in the +in sct + + align:start position:0% +in sct + + + align:start position:0% +in sct +we'll see how that works + + align:start position:0% +we'll see how that works + + + align:start position:0% +we'll see how that works +and that actually leads to convolutions + + align:start position:0% +and that actually leads to convolutions + + + align:start position:0% +and that actually leads to convolutions +in fact exactly this little manipulation + + align:start position:0% +in fact exactly this little manipulation + + + align:start position:0% +in fact exactly this little manipulation +here is what leads to the convolution of + + align:start position:0% +here is what leads to the convolution of + + + align:start position:0% +here is what leads to the convolution of +the part-time distribution function + + align:start position:0% +the part-time distribution function + + + align:start position:0% +the part-time distribution function +with heart scattering if you think about + + align:start position:0% +with heart scattering if you think about + + + align:start position:0% +with heart scattering if you think about +this operator as describing + + align:start position:0% +this operator as describing + + + align:start position:0% +this operator as describing +the matrix elements of this operator as + + align:start position:0% +the matrix elements of this operator as + + + align:start position:0% +the matrix elements of this operator as +describing a part-time distribution + + align:start position:0% +describing a part-time distribution + + + align:start position:0% +describing a part-time distribution +function the wilson's coefficients is + + align:start position:0% +function the wilson's coefficients is + + + align:start position:0% +function the wilson's coefficients is +describing the hard scattering exactly + + align:start position:0% +describing the hard scattering exactly + + + align:start position:0% +describing the hard scattering exactly +this integral is what leads to the + + align:start position:0% +this integral is what leads to the + + + align:start position:0% +this integral is what leads to the +integral + + align:start position:0% +integral + + + align:start position:0% +integral +that convolutes together part-time + + align:start position:0% +that convolutes together part-time + + + align:start position:0% +that convolutes together part-time +distribution functions + + align:start position:0% +distribution functions + + + align:start position:0% +distribution functions +and hard scattering matrix almonds + + align:start position:0% +and hard scattering matrix almonds + + + align:start position:0% +and hard scattering matrix almonds +come back to that + + align:start position:0% + + + + align:start position:0% + +so there's going to be a power counting + + align:start position:0% +so there's going to be a power counting + + + align:start position:0% +so there's going to be a power counting +for this effective theory + + align:start position:0% + + + + align:start position:0% + +and we're going to call the power + + align:start position:0% +and we're going to call the power + + + align:start position:0% +and we're going to call the power +counting parameter lambda + + align:start position:0% +counting parameter lambda + + + align:start position:0% +counting parameter lambda +and it's not going to be related to the + + align:start position:0% +and it's not going to be related to the + + + align:start position:0% +and it's not going to be related to the +mass dimension of fields + + align:start position:0% + + + + align:start position:0% + +we'll have to figure out + + align:start position:0% +we'll have to figure out + + + align:start position:0% +we'll have to figure out +how to do the power counting + + align:start position:0% + + + + align:start position:0% + +there's going to be something called the + + align:start position:0% +there's going to be something called the + + + align:start position:0% +there's going to be something called the +wilson line + + align:start position:0% +wilson line + + + align:start position:0% +wilson line +which show up all over the place in this + + align:start position:0% +which show up all over the place in this + + + align:start position:0% +which show up all over the place in this +effective theory + + align:start position:0% + + + + align:start position:0% + +so these are lines in space that are + + align:start position:0% +so these are lines in space that are + + + align:start position:0% +so these are lines in space that are +coupled to the gauge field a + + align:start position:0% +coupled to the gauge field a + + + align:start position:0% +coupled to the gauge field a +and + + align:start position:0% +and + + + align:start position:0% +and +we'll see why they're showing up but + + align:start position:0% +we'll see why they're showing up but + + + align:start position:0% +we'll see why they're showing up but +it's related actually to the fact that + + align:start position:0% +it's related actually to the fact that + + + align:start position:0% +it's related actually to the fact that +this effective theory has a very + + align:start position:0% +this effective theory has a very + + + align:start position:0% +this effective theory has a very +interesting + + align:start position:0% +interesting + + + align:start position:0% +interesting +and perhaps subtle + + align:start position:0% +and perhaps subtle + + + align:start position:0% +and perhaps subtle +gauge symmetry structure + + align:start position:0% + + + + align:start position:0% + +one way of actually already seeing why + + align:start position:0% +one way of actually already seeing why + + + align:start position:0% +one way of actually already seeing why +that is true is because i told you over + + align:start position:0% +that is true is because i told you over + + + align:start position:0% +that is true is because i told you over +here that we have two types of quarks + + align:start position:0% +here that we have two types of quarks + + + align:start position:0% +here that we have two types of quarks +everything i say about quarks is also + + align:start position:0% +everything i say about quarks is also + + + align:start position:0% +everything i say about quarks is also +true of gluon so there's going to be two + + align:start position:0% +true of gluon so there's going to be two + + + align:start position:0% +true of gluon so there's going to be two +types of gluons an a n gluon and a s + + align:start position:0% +types of gluons an a n gluon and a s + + + align:start position:0% +types of gluons an a n gluon and a s +gluon + + align:start position:0% +gluon + + + align:start position:0% +gluon +and once there's two types of gluons you + + align:start position:0% +and once there's two types of gluons you + + + align:start position:0% +and once there's two types of gluons you +should say well what's the gauge group + + align:start position:0% +should say well what's the gauge group + + + align:start position:0% +should say well what's the gauge group +of this gluon and what's the gauge group + + align:start position:0% +of this gluon and what's the gauge group + + + align:start position:0% +of this gluon and what's the gauge group +of that glue well they're both the same + + align:start position:0% +of that glue well they're both the same + + + align:start position:0% +of that glue well they're both the same +gauge group it's qcd + + align:start position:0% +gauge group it's qcd + + + align:start position:0% +gauge group it's qcd +so we've partitioned qcd in some + + align:start position:0% +so we've partitioned qcd in some + + + align:start position:0% +so we've partitioned qcd in some +kind of weird way where we have two + + align:start position:0% +kind of weird way where we have two + + + align:start position:0% +kind of weird way where we have two +fields for the gage group rather than + + align:start position:0% +fields for the gage group rather than + + + align:start position:0% +fields for the gage group rather than +just one + + align:start position:0% +just one + + + align:start position:0% +just one +part of that story is going to be + + align:start position:0% +part of that story is going to be + + + align:start position:0% +part of that story is going to be +related to these wilson lines + + align:start position:0% + + + + align:start position:0% + +and finally one final kind of + + align:start position:0% +and finally one final kind of + + + align:start position:0% +and finally one final kind of +interesting thing that's going to happen + + align:start position:0% +interesting thing that's going to happen + + + align:start position:0% +interesting thing that's going to happen +is we're going to see when we do one + + align:start position:0% +is we're going to see when we do one + + + align:start position:0% +is we're going to see when we do one +loop calculations in this theory + + align:start position:0% +loop calculations in this theory + + + align:start position:0% +loop calculations in this theory +that we find one over epsilon squared + + align:start position:0% +that we find one over epsilon squared + + + align:start position:0% +that we find one over epsilon squared +divergences + + align:start position:0% + + + + align:start position:0% + +so usually when you do an effective + + align:start position:0% +so usually when you do an effective + + + align:start position:0% +so usually when you do an effective +field theory calculation at one loop you + + align:start position:0% +field theory calculation at one loop you + + + align:start position:0% +field theory calculation at one loop you +find a one over epsilon + + align:start position:0% +find a one over epsilon + + + align:start position:0% +find a one over epsilon +pull not a one over epsilon squared + + align:start position:0% +pull not a one over epsilon squared + + + align:start position:0% +pull not a one over epsilon squared +and i don't + + align:start position:0% +and i don't + + + align:start position:0% +and i don't +denote it by epsilon u v because both + + align:start position:0% +denote it by epsilon u v because both + + + align:start position:0% +denote it by epsilon u v because both +poles here require + + align:start position:0% +poles here require + + + align:start position:0% +poles here require +u v or normalization + + align:start position:0% +u v or normalization + + + align:start position:0% +u v or normalization +we need to add a counter term to cancel + + align:start position:0% +we need to add a counter term to cancel + + + align:start position:0% +we need to add a counter term to cancel +this double pole + + align:start position:0% +this double pole + + + align:start position:0% +this double pole +and exactly the presence of that double + + align:start position:0% +and exactly the presence of that double + + + align:start position:0% +and exactly the presence of that double +pole is what leads to these + + align:start position:0% +pole is what leads to these + + + align:start position:0% +pole is what leads to these +pseudocoph logs that i was mentioning + + align:start position:0% +pseudocoph logs that i was mentioning + + + align:start position:0% +pseudocoph logs that i was mentioning +the fact that we have these double logs + + align:start position:0% +the fact that we have these double logs + + + align:start position:0% +the fact that we have these double logs +going along with each alpha s + + align:start position:0% +going along with each alpha s + + + align:start position:0% +going along with each alpha s +so we'll see that the taking care of + + align:start position:0% +so we'll see that the taking care of + + + align:start position:0% +so we'll see that the taking care of +this for normalization which is a little + + align:start position:0% +this for normalization which is a little + + + align:start position:0% +this for normalization which is a little +different than the normalization you're + + align:start position:0% +different than the normalization you're + + + align:start position:0% +different than the normalization you're +used to + + align:start position:0% +used to + + + align:start position:0% +used to +will allow us to sum up those pseudocoph + + align:start position:0% +will allow us to sum up those pseudocoph + + + align:start position:0% +will allow us to sum up those pseudocoph +logarithms + + align:start position:0% +logarithms + + + align:start position:0% +logarithms +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so that's a kind of + + align:start position:0% +so that's a kind of + + + align:start position:0% +so that's a kind of +hint of the things that we will be + + align:start position:0% +hint of the things that we will be + + + align:start position:0% +hint of the things that we will be +studying + + align:start position:0% +studying + + + align:start position:0% +studying +not supposed to understand any of them + + align:start position:0% +not supposed to understand any of them + + + align:start position:0% +not supposed to understand any of them +yet unless you studied sct but we will + + align:start position:0% +yet unless you studied sct but we will + + + align:start position:0% +yet unless you studied sct but we will +understand all of these by the end of + + align:start position:0% +understand all of these by the end of + + + align:start position:0% +understand all of these by the end of +the course + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +any question anything i missed on my + + align:start position:0% +any question anything i missed on my + + + align:start position:0% +any question anything i missed on my +list + + align:start position:0% + + + + align:start position:0% + +all right + + align:start position:0% + + + + align:start position:0% + +so let's spend some time talking about + + align:start position:0% +so let's spend some time talking about + + + align:start position:0% +so let's spend some time talking about +degrees of freedom + + align:start position:0% + + + + align:start position:0% + +the way i like to think about degrees of + + align:start position:0% +the way i like to think about degrees of + + + align:start position:0% +the way i like to think about degrees of +freedom for any effective field theory + + align:start position:0% +freedom for any effective field theory + + + align:start position:0% +freedom for any effective field theory +is this is where you have to think about + + align:start position:0% +is this is where you have to think about + + + align:start position:0% +is this is where you have to think about +the physics of what you're doing + + align:start position:0% +the physics of what you're doing + + + align:start position:0% +the physics of what you're doing +okay so let's think about some physical + + align:start position:0% +okay so let's think about some physical + + + align:start position:0% +okay so let's think about some physical +process i'm going to consider two + + align:start position:0% +process i'm going to consider two + + + align:start position:0% +process i'm going to consider two +different physical processes + + align:start position:0% +different physical processes + + + align:start position:0% +different physical processes +actually today i'll only start talking + + align:start position:0% +actually today i'll only start talking + + + align:start position:0% +actually today i'll only start talking +about one of them and then we'll talk + + align:start position:0% +about one of them and then we'll talk + + + align:start position:0% +about one of them and then we'll talk +about the other one next time + + align:start position:0% +about the other one next time + + + align:start position:0% +about the other one next time +think about some physical process and + + align:start position:0% +think about some physical process and + + + align:start position:0% +think about some physical process and +try to identify what the right degrees + + align:start position:0% +try to identify what the right degrees + + + align:start position:0% +try to identify what the right degrees +of freedom are + + align:start position:0% + + + + align:start position:0% + +so you could look at the process of a + + align:start position:0% +so you could look at the process of a + + + align:start position:0% +so you could look at the process of a +beam azon changing into a d meson and a + + align:start position:0% +beam azon changing into a d meson and a + + + align:start position:0% +beam azon changing into a d meson and a +pion + + align:start position:0% +pion + + + align:start position:0% +pion +the advantage of starting with this one + + align:start position:0% +the advantage of starting with this one + + + align:start position:0% +the advantage of starting with this one +is that we've already talked about hqet + + align:start position:0% +is that we've already talked about hqet + + + align:start position:0% +is that we've already talked about hqet +so we understand how to do b mesons and + + align:start position:0% +so we understand how to do b mesons and + + + align:start position:0% +so we understand how to do b mesons and +d masons we just have to understand how + + align:start position:0% +d masons we just have to understand how + + + align:start position:0% +d masons we just have to understand how +to do the pion + + align:start position:0% + + + + align:start position:0% + +so we have a b mouse on let's think + + align:start position:0% +so we have a b mouse on let's think + + + align:start position:0% +so we have a b mouse on let's think +about it in the rest frame + + align:start position:0% +about it in the rest frame + + + align:start position:0% +about it in the rest frame +the case to a very heavy demelzon and a + + align:start position:0% +the case to a very heavy demelzon and a + + + align:start position:0% +the case to a very heavy demelzon and a +very light pion + + align:start position:0% + + + + align:start position:0% + +so the demelzon we can treat with hqet + + align:start position:0% +so the demelzon we can treat with hqet + + + align:start position:0% +so the demelzon we can treat with hqet +the bmilson we can trade with each hqet + + align:start position:0% +the bmilson we can trade with each hqet + + + align:start position:0% +the bmilson we can trade with each hqet +the problem is this pion because it's + + align:start position:0% +the problem is this pion because it's + + + align:start position:0% +the problem is this pion because it's +very energetic + + align:start position:0% + + + + align:start position:0% + +if you look at the + + align:start position:0% +if you look at the + + + align:start position:0% +if you look at the +momentum of that pion and the way i've + + align:start position:0% +momentum of that pion and the way i've + + + align:start position:0% +momentum of that pion and the way i've +drawn it + + align:start position:0% + + + + align:start position:0% + +and you put in some numbers just to + + align:start position:0% +and you put in some numbers just to + + + align:start position:0% +and you put in some numbers just to +get a sense of what we're talking about + + align:start position:0% + + + + align:start position:0% + +then it's got an energy which is + + align:start position:0% +then it's got an energy which is + + + align:start position:0% +then it's got an energy which is +slightly bigger than the momentum and + + align:start position:0% +slightly bigger than the momentum and + + + align:start position:0% +slightly bigger than the momentum and +that's because it has a mass but it's a + + align:start position:0% +that's because it has a mass but it's a + + + align:start position:0% +that's because it has a mass but it's a +pretty small + + align:start position:0% + + + + align:start position:0% + +mass squared minus p squared is 135 + + align:start position:0% +mass squared minus p squared is 135 + + + align:start position:0% +mass squared minus p squared is 135 +mmv + + align:start position:0% +mmv + + + align:start position:0% +mmv +squared + + align:start position:0% + + + + align:start position:0% + +and so if you look at that + + align:start position:0% +and so if you look at that + + + align:start position:0% +and so if you look at that +you see + + align:start position:0% +you see + + + align:start position:0% +you see +that this momentum of the pion is very + + align:start position:0% +that this momentum of the pion is very + + + align:start position:0% +that this momentum of the pion is very +close to the light cone the light cone + + align:start position:0% +close to the light cone the light cone + + + align:start position:0% +close to the light cone the light cone +would be if these two are equal + + align:start position:0% +would be if these two are equal + + + align:start position:0% +would be if these two are equal +that's + + align:start position:0% +that's + + + align:start position:0% +that's +what a massless particle would do + + align:start position:0% +what a massless particle would do + + + align:start position:0% +what a massless particle would do +ion is pretty light + + align:start position:0% +ion is pretty light + + + align:start position:0% +ion is pretty light +and it's moving relativistically + + align:start position:0% +and it's moving relativistically + + + align:start position:0% +and it's moving relativistically +and there's no sense in which we can + + align:start position:0% +and there's no sense in which we can + + + align:start position:0% +and there's no sense in which we can +think about 2.3 gv is a small scale + + align:start position:0% +think about 2.3 gv is a small scale + + + align:start position:0% +think about 2.3 gv is a small scale +we're not going to expand in 2.3 gb over + + align:start position:0% +we're not going to expand in 2.3 gb over + + + align:start position:0% +we're not going to expand in 2.3 gb over +mb because that's a pretty lousy + + align:start position:0% +mb because that's a pretty lousy + + + align:start position:0% +mb because that's a pretty lousy +expansion + + align:start position:0% + + + + align:start position:0% + +so p pi mu here + + align:start position:0% +so p pi mu here + + + align:start position:0% +so p pi mu here +is basically some scale times a light + + align:start position:0% +is basically some scale times a light + + + align:start position:0% +is basically some scale times a light +like vector + + align:start position:0% +like vector + + + align:start position:0% +like vector +where n mu + + align:start position:0% +where n mu + + + align:start position:0% +where n mu +is one + + align:start position:0% +is one + + + align:start position:0% +is one +zero zero minus one + + align:start position:0% +zero zero minus one + + + align:start position:0% +zero zero minus one +and that's to a good approximation + + align:start position:0% +and that's to a good approximation + + + align:start position:0% +and that's to a good approximation +you can see how good over there + + align:start position:0% + + + + align:start position:0% + +so we're going to use light like vectors + + align:start position:0% +so we're going to use light like vectors + + + align:start position:0% +so we're going to use light like vectors +to talk about particles like a pion + + align:start position:0% +to talk about particles like a pion + + + align:start position:0% +to talk about particles like a pion +so n mu is a light like vector + + align:start position:0% +so n mu is a light like vector + + + align:start position:0% +so n mu is a light like vector +n squared is zero + + align:start position:0% + + + + align:start position:0% + +and what we're going to be expanding in + + align:start position:0% +and what we're going to be expanding in + + + align:start position:0% +and what we're going to be expanding in +instead of expanding in q over mb + + align:start position:0% +instead of expanding in q over mb + + + align:start position:0% +instead of expanding in q over mb +q of the pion we're going to + + align:start position:0% + + + + align:start position:0% + +think about the dynamics with this q + + align:start position:0% +think about the dynamics with this q + + + align:start position:0% +think about the dynamics with this q +scale 2.3 gv as being much bigger than + + align:start position:0% +scale 2.3 gv as being much bigger than + + + align:start position:0% +scale 2.3 gv as being much bigger than +lambda qcd + + align:start position:0% + + + + align:start position:0% + +so we're going to use for particles like + + align:start position:0% +so we're going to use for particles like + + + align:start position:0% +so we're going to use for particles like +this pion that are very energetic light + + align:start position:0% +this pion that are very energetic light + + + align:start position:0% +this pion that are very energetic light +cone coordinates + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +when you have a light cone vector like n + + align:start position:0% +when you have a light cone vector like n + + + align:start position:0% +when you have a light cone vector like n +and you want to decompose any vector in + + align:start position:0% +and you want to decompose any vector in + + + align:start position:0% +and you want to decompose any vector in +terms of it + + align:start position:0% +terms of it + + + align:start position:0% +terms of it +you need another auxiliary vector which + + align:start position:0% +you need another auxiliary vector which + + + align:start position:0% +you need another auxiliary vector which +i'm going to call in bar + + align:start position:0% +i'm going to call in bar + + + align:start position:0% +i'm going to call in bar +so these are two light-like vectors + + align:start position:0% +so these are two light-like vectors + + + align:start position:0% +so these are two light-like vectors +they both square to zero + + align:start position:0% +they both square to zero + + + align:start position:0% +they both square to zero +and the reason i need two of them is + + align:start position:0% +and the reason i need two of them is + + + align:start position:0% +and the reason i need two of them is +because i need some notion of + + align:start position:0% +because i need some notion of + + + align:start position:0% +because i need some notion of +orthogonality so you should think of + + align:start position:0% +orthogonality so you should think of + + + align:start position:0% +orthogonality so you should think of +nvar as like the complementary vector + + align:start position:0% +nvar as like the complementary vector + + + align:start position:0% +nvar as like the complementary vector +to n + + align:start position:0% +to n + + + align:start position:0% +to n +the dual vector in the orthogonal + + align:start position:0% +the dual vector in the orthogonal + + + align:start position:0% +the dual vector in the orthogonal +sense + + align:start position:0% + + + + align:start position:0% + +so with those two vectors you can + + align:start position:0% +so with those two vectors you can + + + align:start position:0% +so with those two vectors you can +decompose any vector in terms of + + align:start position:0% + + + + align:start position:0% + +use them as a basis + + align:start position:0% + + + + align:start position:0% + +this is how it works + + align:start position:0% +this is how it works + + + align:start position:0% +this is how it works +my conventions + + align:start position:0% +my conventions + + + align:start position:0% +my conventions +so you have + + align:start position:0% +so you have + + + align:start position:0% +so you have +two components that you can decompose + + align:start position:0% +two components that you can decompose + + + align:start position:0% +two components that you can decompose +along n and n bar + + align:start position:0% +along n and n bar + + + align:start position:0% +along n and n bar +and the value of the the momentum along + + align:start position:0% +and the value of the the momentum along + + + align:start position:0% +and the value of the the momentum along +that direction is the complementary + + align:start position:0% +that direction is the complementary + + + align:start position:0% +that direction is the complementary +vector dotted into p + + align:start position:0% + + + + align:start position:0% + +and so we usually with this notation we + + align:start position:0% +and so we usually with this notation we + + + align:start position:0% +and so we usually with this notation we +call n bar dot p p minus + + align:start position:0% +call n bar dot p p minus + + + align:start position:0% +call n bar dot p p minus +so that's just a shorthand + + align:start position:0% +so that's just a shorthand + + + align:start position:0% +so that's just a shorthand +and n dot p is p plus + + align:start position:0% + + + + align:start position:0% + +okay so it's going to be useful to + + align:start position:0% +okay so it's going to be useful to + + + align:start position:0% +okay so it's going to be useful to +decompose things along these directions + + align:start position:0% +decompose things along these directions + + + align:start position:0% +decompose things along these directions +for the same reason that you kind of saw + + align:start position:0% +for the same reason that you kind of saw + + + align:start position:0% +for the same reason that you kind of saw +here that the pion was naturally + + align:start position:0% +here that the pion was naturally + + + align:start position:0% +here that the pion was naturally +decomposing itself along a particular + + align:start position:0% +decomposing itself along a particular + + + align:start position:0% +decomposing itself along a particular +light-like direction + + align:start position:0% +light-like direction + + + align:start position:0% +light-like direction +so we're going to want to do that more + + align:start position:0% +so we're going to want to do that more + + + align:start position:0% +so we're going to want to do that more +generally and that's how we'll do it for + + align:start position:0% +generally and that's how we'll do it for + + + align:start position:0% +generally and that's how we'll do it for +momenta + + align:start position:0% + + + + align:start position:0% + +if we talk about p squared + + align:start position:0% + + + + align:start position:0% + +and i just square the components here + + align:start position:0% +and i just square the components here + + + align:start position:0% +and i just square the components here +n dotted into perp is zero + + align:start position:0% +n dotted into perp is zero + + + align:start position:0% +n dotted into perp is zero +and bar dotted into purpose zero there's + + align:start position:0% +and bar dotted into purpose zero there's + + + align:start position:0% +and bar dotted into purpose zero there's +a non-trivial crop this squared is zero + + align:start position:0% +a non-trivial crop this squared is zero + + + align:start position:0% +a non-trivial crop this squared is zero +that's square root of zero there's a + + align:start position:0% +that's square root of zero there's a + + + align:start position:0% +that's square root of zero there's a +non-trivial cross term between those two + + align:start position:0% +non-trivial cross term between those two + + + align:start position:0% +non-trivial cross term between those two +which is this + + align:start position:0% +which is this + + + align:start position:0% +which is this +this guy can be squared + + align:start position:0% + + + + align:start position:0% + +if we use our shorthand then it's + + align:start position:0% +if we use our shorthand then it's + + + align:start position:0% +if we use our shorthand then it's +this + + align:start position:0% +this + + + align:start position:0% +this +and if we want to use euclidean + + align:start position:0% +and if we want to use euclidean + + + align:start position:0% +and if we want to use euclidean +notation + + align:start position:0% +notation + + + align:start position:0% +notation +then i can + + align:start position:0% +then i can + + + align:start position:0% +then i can +i'll switch and i'll + + align:start position:0% +i'll switch and i'll + + + align:start position:0% +i'll switch and i'll +say that p perp squared which is a + + align:start position:0% +say that p perp squared which is a + + + align:start position:0% +say that p perp squared which is a +minkowski negative quantity is minus p + + align:start position:0% +minkowski negative quantity is minus p + + + align:start position:0% +minkowski negative quantity is minus p +vector perp squared + + align:start position:0% +vector perp squared + + + align:start position:0% +vector perp squared +where p vector perp squared is euclidean + + align:start position:0% + + + + align:start position:0% + +so sometimes i'll have + + align:start position:0% +so sometimes i'll have + + + align:start position:0% +so sometimes i'll have +used for both of those notations + + align:start position:0% +used for both of those notations + + + align:start position:0% +used for both of those notations +all right so i think we're out of time + + align:start position:0% +all right so i think we're out of time + + + align:start position:0% +all right so i think we're out of time +for today we'll continue with this + + align:start position:0% +for today we'll continue with this + + + align:start position:0% +for today we'll continue with this +discussion of degrees of freedom next + + align:start position:0% +discussion of degrees of freedom next + + + align:start position:0% +discussion of degrees of freedom next +time + + align:start position:0% +time + + + align:start position:0% +time +and + + align:start position:0% +and + + + align:start position:0% +and +talk a little bit more about coordinates + + align:start position:0% +talk a little bit more about coordinates + + + align:start position:0% +talk a little bit more about coordinates +as well \ No newline at end of file diff --git a/DjMaDN3EtWc.txt b/DjMaDN3EtWc.txt new file mode 100644 index 0000000000000000000000000000000000000000..e0581e2ab349f9d20a52563d31f6acfd25e2fc20 --- /dev/null +++ b/DjMaDN3EtWc.txt @@ -0,0 +1,476 @@ +Servomotors are widely used electro-mechanical +components. For example, they are used in + +steering systems for scale model helicopters +and other radio controlled cars, robots, and + +aircraft, including military "drones". + +A servomotor includes an electric motor, circuitry +to control its speed and direction, and gearing + +to attain the high torques needed to apply +moderately large forces over relatively short + +linear displacements. The gearing inside this +servo is a compound gear train with four stages. + +In this video, we will understand how linear +algebra can help us to predict the losses + +and understand the design trade-offs when +converting high speeds and low torques into + +low speeds and high torques using a gear train. + +This video is part of the Linearity Video +Series. Many complex systems are modeled or + +approximated linearly because of the mathematical +advantages. + +Hi, my name is Dan Frey, and I am a professor +of Mechanical Engineering and Engineering + +Systems at MIT. + +Before watching this video, you should be +able to identify and describe the forces and + +torques that act on a system. + +After watching this video and some practice, +you will be able to: + +Model the forces and torques in a gear train +as a system of linear equations. + +Combine these linear equations into a matrix +equation. + +First, let's get a quick overview of the design. +Here's a servomotor with the case opened. + +Inside the case is a DC motor with a small +pinion gear on it. The pinion has 10 teeth + +and is mated to a gear with 72 teeth. So the +first pair provides a speed reduction of 7.2:1. + +This large, 72 tooth gear is part of a single +molding with a 10 tooth gear. + +The 10 tooth gear on top of the 72 tooth gear +is mated to a plastic gear with 48 teeth as + +you see here. So that stage provides a speed +reduction of 4.8:1. The 48 tooth gear is molded + +to another 10 tooth gear. + +The 11-tooth gear is mated to a black 36-tooth +gear. This 36-tooth gear is molded to a 16-tooth + +gear. The 16-tooth gear is mated to this black +42 tooth gear, which is splined onto the output + +shaft. + +The overall sequence of gear pairs is: 10 +teeth mated to 72 teeth, 10 mated to 48, 11 + +mated to 36 and finally 16 mated to 42 teeth +on the splined output shaft. + +The overall gear ratio is the product of all +the gear ratios of the gear pairs in the train. + +Therefore about 326 to 1 as shown by this +formula. + +Based on the motor's output and some measurement +and calculation, we would expect an output + +torque of 6.8 Newton meters in an idealized +gear train. + +But there are frictional losses at every stage +of the power transmission process, so we guess + +the output shaft will provide substantially +less torque than that. So let's start by measuring + +the maximum force at the output shaft, and +convert that to an output torque. + +We attach weights to a servo horn that has +been connected with the output shaft on the + +servomotor. An electrical power source (in +this case, a battery) is connected through + +a radio controller. + +Here you see the servomotor lifting 1 kg. +Here it is lifting about 2kg. And here it + +lifts even 3kg! This lightweight (100 gram) +servomotor produces large amounts of torque, + +which can apparently lift more than 30 times +its own weight. + +In this set-up, the servomotor will lift a +4.42kg weight starting from a 90 degree angle. + +As the motor lifts the weight, the readout +on the scale should change. + +Here you see the initial weight, with slack +in the string, is 9.75 lbs. This is about + +4.42kg. With the motor pulling at maximum +capacity, the scale reads 3.70 lbs, which + +is 1.68 kg. + +A calculation tells us that the maximum torque +available at the output shaft according to + +our tests is 1.47 Newton meters. + +We can use linear algebra to work out a better +estimate. The force transmission and frictional + +losses in each step of the train can be modeled +by a set of linear equations, (summing forces + +and summing torques on the rigid body). For +the three rigid bodies that are comprised + +of two gears molded together, we will need +three equations (sums of separate x and y + +forces and sums of torques). + +The pinion gear and last gear in the train +are simpler, because there is only one gear + +in the body, so we can combine each of those +into a single equation. + +The equations modeling the entire train can +be assembled by linking together the five + +sets of equations with four additional equations +to link each mating pair, so the overall system + +will have 15 equations--- 3 sets of 3 each +(9 total) plus 1 each for the input and output + +gears plus 4 equations that model the connections +between the mating gears. The solution to + +that set of equations helps us to estimate +performance of the machine and also gives + +us insight into its design. + +Let's make the model of just one gear body +now, say the 10 tooth and 48 tooth molded + +gear seen here. One way to model the system +is to posit that there are three unknown forces + +acting on this single body of two gears molded +together. + +We can name these forces F-TL2, F-TS2 , F-ShaftX2, +and F-ShaftY2. The force F-TL2 is a force + +tangent to the gear pitch circle on the larger +of the two gears. The T is for Tangent, the + +L is for Large, and the 2 indicates that this +is the second compound gear in the train. + +The force F-TS2 is a force tangent to the +gear pitch circle on the smaller of the two + +gears. Again the T means tangent, and the +S here means small. + +Recall that these tangential forces really +come from forces normal to the gear teeth. + +These gears are designed so that all of the +gears in this servomotor have a pressure angle + +of 20 degrees. So there is a X component to +this force, the separation force between the + +mating gears, which has magnitude given by +FTL2 and FTS2 times tan 0.35, where 0.35 is + +20 degrees expressed in radians. + +The forces F-ShaftX2 and F-ShaftY2 are the +X and Y components of the normal force to + +the shaft, which is applied to the gear it +supports. + +There are also frictional forces associated +with the normal force supporting the shaft, + +but they are not separate unknowns, they link +the X and Y components normal forces by the + +friction coefficient, mu2. + +This completes the description of the unknown +forces in our model. Those four forces appear + +in three different linear equations as represented +by this matrix: + +Take a moment to verify that these equations +balance the forces and torques. + +The +first row in the matrix represents a sum of +the forces on the gear in the X direction. + +The second row represents a sum of the forces +on the gear in the Y direction. The third + +row represents a sum of the torques or moments +on the gear in the direction parallel to the + +gear shaft. + +Now let's work on the model of the next gear +in the train -- the one with 16 teeth and + +36 teeth molded together. Again, we model +the system by positing that there are four + +unknown forces acting on this single body +having two gears molded together and we can + +name these forces FTL3, FTS3 , FShaftX3, and +FShaftY3. And we obtain this matrix. + +How can we link these two matrices together +to get a model of the second and third gears + +combined? We see that the smaller gear on +body 2 is in contact with the larger gear + +on body 3. According to Newton's third law, +the reaction force on body 2 should be equal + +and opposite to that on body 3. + +In fact, the situation is more complex. As +the gears enter mating they slide into engagement. + +As the gears depart contact, they slide back +out. There are losses at the interface that + +are complex to model, and we will represent +them simply using the efficiency in the average + +transmitted force. + +Now we can join the model of the second gear +and the third gear into a single system of + +linear equations represented by this matrix: + +The row in the middle is like "glue" holding +the two models together. The force on the + +large gear on body 3 is equal to the force +on the large gear on body 2 except a penalty + +is applied for inefficiencies. The principal +mechanism for loss of power and torque is + +sliding friction -- in this case, shearing +the lubricant on the gear faces. + +Before going on to assemble more of the model, +it is worth inspecting our work so far for + +patterns. Note that the top right and bottom +left of our matrices are filled with 3x4 matrices + +of zeros. That is a clue that our matrix is +shaping up to be banded in structure. Although + +every variable affects every other variable, +the influences propagate locally (in some + +sense). For example, the frictional losses +on shaft 2 do influence the frictional losses + +on shaft 3, but only indirectly through their +effect on the force between the two bodies. + +Because we arranged the variables in our vectors +in a way that respects this structure, our + +matrix has a band in the middle from the top +left corner to the bottom right. We will try + +to keep this up as we continue building the +model. It will clarify interpretation of the + +model and also aid in efficiency and stability +of the computations needed to solve it. + +Now it's your turn, take a moment to write +a matrix that models the force and torque + +balance on the first rigid body gear in the +gear train. + +This matrix is completely analogous to the +matrices we obtained in for the 2nd and 3rd + +gear bodies. + +When we add the pinion gear and fourth gear +into the model, we need to take additional + +care. These will have slightly different structure. +The gear connected to the pinion on the motor + +has an applied torque due to the motor. The +reaction at the output shaft is an externally + +applied torque, due entirely to the large +fourth gear. It is possible to combine these + +into a single equation for each gear. + +Pause the video and try to write out the full +system of linear equations for the overall + +4 gear train system. + +Placing these into the model as the first +and last rows, the overall system of linear + +equations is: + +Note that the matrix has 15 rows and 15 columns. +This should be expected as the system should + +be neither overdetermined nor underdetermined. +Given a particular torque input at the motor, + +there should be a single value of output torque +consistent with our gear train model and its + +deterministically defined parameters. + +By solving this system, we find unique values +for all the unknowns. When we assembled the + +equations, we guessed the direction of each +force in the free body diagram. So, it's useful + +to inspect the solution for negative values. +For the parameter values we chose, the reaction + +force at the shaft of the third body in the +x direction turns out to be negative. + +We should ask ourselves, did we guess wrong +about the direction of the force, or is there + +something wrong with our matrix? Looking at +the forces computed it seems that the friction + +in the x direction due to support of the large +y reaction on this gear was more dominant + +that we expected. + +It's sensible to run some sanity checks in +a case like this. If the friction on that + +gear were very low, would the sign be positive +as expected? We ran that scenario, and the + +sign did become positive. So our guess about +the direction of the reaction force was wrong. + +Our assumptions for the magnitude of the friction +were too low. But it seems the model is behaving + +in reasonable ways. + +Now that we have a reasonable level of confidence +in the model, we can begin to use it to explore + +the design decisions that the engineers made. +If we put in reasonable values for the gear + +mating efficiency, such as 96%, and reasonable +values for the friction coefficients at the + +bushings, such as 0.3, we find an overall +efficiency of the gear train is about 52%. + +This is in reasonable agreement with our simple +measurements. We found that the maximum torque + +available at the output shaft is 1.47 Newton +meters, which would imply an efficiency closer + +to 25%. + +But our measurement used an overhanging load, +which caused the shaft to bend. Our simple + +model makes a large and optimistic assumption +of loading the servomotor with torques only. + +It's not surprising that the answers differ +substantially. It suggests installing the + +servo so that bending loads are supported +elsewhere, not in the servo itself. + +The gears in automotive transmissions with +similar ratios are much more efficient, perhaps + +90% to 95% efficient. But for a compact and +inexpensive gear train, this design performs + +well, especially since the plastic the gears +are molded from adds a great deal of rolling + +friction. + +To summarize, we built an engineering model +of a servomotor gear train using systems of + +linear equations. The matrix representations +helped us to explore the interactions among + +variables in the system like separation forces +between gears and friction at the shafts. + +Since the 15 by 15 system of equations is +so fast and easy to solve on a modern computer, + +we could run a large number of "what if" scenarios. + +We hope this video helped you see how linear +algebra can be used to make and understand + +engineering design decisions. \ No newline at end of file diff --git a/DpNZ70Uam0M.txt b/DpNZ70Uam0M.txt new file mode 100644 index 0000000000000000000000000000000000000000..007e5e9decee69838341bfea41a139fd5ea303ee --- /dev/null +++ b/DpNZ70Uam0M.txt @@ -0,0 +1,6323 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT OpenCourseWare continue to + + align:start position:0% +will help MIT OpenCourseWare continue to + + + align:start position:0% +will help MIT OpenCourseWare continue to +offer high quality educational resources + + align:start position:0% +offer high quality educational resources + + + align:start position:0% +offer high quality educational resources +for free + + align:start position:0% +for free + + + align:start position:0% +for free +to make a donation or to view additional + + align:start position:0% +to make a donation or to view additional + + + align:start position:0% +to make a donation or to view additional +materials from hundreds of MIT courses + + align:start position:0% +materials from hundreds of MIT courses + + + align:start position:0% +materials from hundreds of MIT courses +visit MIT opencourseware at ocw.mit.edu + + align:start position:0% + + + + align:start position:0% + +I'm really I'm really sick today and I + + align:start position:0% +I'm really I'm really sick today and I + + + align:start position:0% +I'm really I'm really sick today and I +hope I can make it through this lecture + + align:start position:0% +hope I can make it through this lecture + + + align:start position:0% +hope I can make it through this lecture +without disgracing myself but this is a + + align:start position:0% +without disgracing myself but this is a + + + align:start position:0% +without disgracing myself but this is a +favorite topic of mine too so maybe + + align:start position:0% +favorite topic of mine too so maybe + + + align:start position:0% +favorite topic of mine too so maybe +we'll be okay so we're going to talk + + align:start position:0% +we'll be okay so we're going to talk + + + align:start position:0% +we'll be okay so we're going to talk +about the helium atom which is really an + + align:start position:0% +about the helium atom which is really an + + + align:start position:0% +about the helium atom which is really an +amazing thing because hydrogen is + + align:start position:0% +amazing thing because hydrogen is + + + align:start position:0% +amazing thing because hydrogen is +possible to solve it exactly all sorts + + align:start position:0% +possible to solve it exactly all sorts + + + align:start position:0% +possible to solve it exactly all sorts +of fantastic things happened and it + + align:start position:0% +of fantastic things happened and it + + + align:start position:0% +of fantastic things happened and it +seemed like just a small step from + + align:start position:0% +seemed like just a small step from + + + align:start position:0% +seemed like just a small step from +hydrogen to helium and nobody can take + + align:start position:0% +hydrogen to helium and nobody can take + + + align:start position:0% +hydrogen to helium and nobody can take +that step it's entirely approximate and + + align:start position:0% +that step it's entirely approximate and + + + align:start position:0% +that step it's entirely approximate and +you can do better and better on the + + align:start position:0% +you can do better and better on the + + + align:start position:0% +you can do better and better on the +approximations but we'd like to have + + align:start position:0% +approximations but we'd like to have + + + align:start position:0% +approximations but we'd like to have +some some physical sense of what's going + + align:start position:0% +some some physical sense of what's going + + + align:start position:0% +some some physical sense of what's going +on and what are the important terms and + + align:start position:0% +on and what are the important terms and + + + align:start position:0% +on and what are the important terms and +can we steal things from hydrogen and + + align:start position:0% +can we steal things from hydrogen and + + + align:start position:0% +can we steal things from hydrogen and +the answer is yeah we can and that was + + align:start position:0% +the answer is yeah we can and that was + + + align:start position:0% +the answer is yeah we can and that was +what last lecture was mostly about the + + align:start position:0% +what last lecture was mostly about the + + + align:start position:0% +what last lecture was mostly about the +energies for hydrogen are minus Z + + align:start position:0% +energies for hydrogen are minus Z + + + align:start position:0% +energies for hydrogen are minus Z +squared H C time to rid burg over N + + align:start position:0% +squared H C time to rid burg over N + + + align:start position:0% +squared H C time to rid burg over N +squared and we have the ionization + + align:start position:0% +squared and we have the ionization + + + align:start position:0% +squared and we have the ionization +energy from the nth level and so this + + align:start position:0% +energy from the nth level and so this + + + align:start position:0% +energy from the nth level and so this +actually is the way we make a link to + + align:start position:0% +actually is the way we make a link to + + + align:start position:0% +actually is the way we make a link to +this concept of electronegativity + + align:start position:0% +this concept of electronegativity + + + align:start position:0% +this concept of electronegativity +because the dominant thing in + + align:start position:0% +because the dominant thing in + + + align:start position:0% +because the dominant thing in +electronegativity is the ionization + + align:start position:0% +electronegativity is the ionization + + + align:start position:0% +electronegativity is the ionization +energy and this is the ionization energy + + align:start position:0% +energy and this is the ionization energy + + + align:start position:0% +energy and this is the ionization energy +and when you put them together and solve + + align:start position:0% +and when you put them together and solve + + + align:start position:0% +and when you put them together and solve +for n you get this arrangement hcz + + align:start position:0% +for n you get this arrangement hcz + + + align:start position:0% +for n you get this arrangement hcz +squared times the red burg over the + + align:start position:0% +squared times the red burg over the + + + align:start position:0% +squared times the red burg over the +ionization energy square root that's N + + align:start position:0% +ionization energy square root that's N + + + align:start position:0% +ionization energy square root that's N +or the effective principal quantum + + align:start position:0% +or the effective principal quantum + + + align:start position:0% +or the effective principal quantum +number and then we have all of these + + align:start position:0% +number and then we have all of these + + + align:start position:0% +number and then we have all of these +formulas that can be derived from + + align:start position:0% +formulas that can be derived from + + + align:start position:0% +formulas that can be derived from +hydrogenic wave functions both for + + align:start position:0% +hydrogenic wave functions both for + + + align:start position:0% +hydrogenic wave functions both for +diagonal make spectate invaluable + + align:start position:0% +diagonal make spectate invaluable + + + align:start position:0% +diagonal make spectate invaluable +matrix elements they're all close form + + align:start position:0% +matrix elements they're all close form + + + align:start position:0% +matrix elements they're all close form +and this is wonderful because it then + + align:start position:0% +and this is wonderful because it then + + + align:start position:0% +and this is wonderful because it then +enables you to use the formulas that are + + align:start position:0% +enables you to use the formulas that are + + + align:start position:0% +enables you to use the formulas that are +obtained exactly for hydrogenic wave + + align:start position:0% +obtained exactly for hydrogenic wave + + + align:start position:0% +obtained exactly for hydrogenic wave +functions and so if we know the + + align:start position:0% +functions and so if we know the + + + align:start position:0% +functions and so if we know the +dependence of an electronic property on + + align:start position:0% +dependence of an electronic property on + + + align:start position:0% +dependence of an electronic property on +N and Al now L is well n is + + align:start position:0% +N and Al now L is well n is + + + align:start position:0% +N and Al now L is well n is +experimentally determined the distance + + align:start position:0% +experimentally determined the distance + + + align:start position:0% +experimentally determined the distance +from ionization L is determined from or + + align:start position:0% +from ionization L is determined from or + + + align:start position:0% +from ionization L is determined from or +angular momentum then we can determine + + align:start position:0% +angular momentum then we can determine + + + align:start position:0% +angular momentum then we can determine +the expected scaling of everything on + + align:start position:0% +the expected scaling of everything on + + + align:start position:0% +the expected scaling of everything on +the quantum numbers and even if that's + + align:start position:0% +the quantum numbers and even if that's + + + align:start position:0% +the quantum numbers and even if that's +wrong it tells you the the qualitative + + align:start position:0% +wrong it tells you the the qualitative + + + align:start position:0% +wrong it tells you the the qualitative +effects when you get to more complicated + + align:start position:0% +effects when you get to more complicated + + + align:start position:0% +effects when you get to more complicated +systems than one electron atoms and this + + align:start position:0% +systems than one electron atoms and this + + + align:start position:0% +systems than one electron atoms and this +is really what I meant by structure + + align:start position:0% +is really what I meant by structure + + + align:start position:0% +is really what I meant by structure +where everything is related to basically + + align:start position:0% +where everything is related to basically + + + align:start position:0% +where everything is related to basically +one observation there's one other thing + + align:start position:0% +one observation there's one other thing + + + align:start position:0% +one observation there's one other thing +that I haven't been stress and it's + + align:start position:0% +that I haven't been stress and it's + + + align:start position:0% +that I haven't been stress and it's +another concept from 511 to and that + + align:start position:0% +another concept from 511 to and that + + + align:start position:0% +another concept from 511 to and that +shielding so suppose we have a sodium + + align:start position:0% +shielding so suppose we have a sodium + + + align:start position:0% +shielding so suppose we have a sodium +atom most of the electrons are in a + + align:start position:0% +atom most of the electrons are in a + + + align:start position:0% +atom most of the electrons are in a +compact core the outer electron sees a + + align:start position:0% +compact core the outer electron sees a + + + align:start position:0% +compact core the outer electron sees a +charge of one even though the charge on + + align:start position:0% +charge of one even though the charge on + + + align:start position:0% +charge of one even though the charge on +the nucleus is larger than one and + + align:start position:0% +the nucleus is larger than one and + + + align:start position:0% +the nucleus is larger than one and +there's if you ask well suppose we look + + align:start position:0% +there's if you ask well suppose we look + + + align:start position:0% +there's if you ask well suppose we look +at this inner region and we have an + + align:start position:0% +at this inner region and we have an + + + align:start position:0% +at this inner region and we have an +electron inside of it the charge that + + align:start position:0% +electron inside of it the charge that + + + align:start position:0% +electron inside of it the charge that +that electron sees is the amount of + + align:start position:0% +that electron sees is the amount of + + + align:start position:0% +that electron sees is the amount of +electrons inside the sphere defined by + + align:start position:0% +electrons inside the sphere defined by + + + align:start position:0% +electrons inside the sphere defined by +this radius and and so the Z we can call + + align:start position:0% +this radius and and so the Z we can call + + + align:start position:0% +this radius and and so the Z we can call +it the Z effective is a function of R + + align:start position:0% +it the Z effective is a function of R + + + align:start position:0% +it the Z effective is a function of R +and you have a different function for a + + align:start position:0% +and you have a different function for a + + + align:start position:0% +and you have a different function for a +real and so it's a way of putting in + + align:start position:0% +real and so it's a way of putting in + + + align:start position:0% +real and so it's a way of putting in +more insight and I I've made a lot of + + align:start position:0% +more insight and I I've made a lot of + + + align:start position:0% +more insight and I I've made a lot of +mileage in my career on these sorts of + + align:start position:0% +mileage in my career on these sorts of + + + align:start position:0% +mileage in my career on these sorts of +scaling arguments + + align:start position:0% +scaling arguments + + + align:start position:0% +scaling arguments +okay so helium the notes are beautiful + + align:start position:0% +okay so helium the notes are beautiful + + + align:start position:0% +okay so helium the notes are beautiful +they're written by Troy and they're very + + align:start position:0% +they're written by Troy and they're very + + + align:start position:0% +they're written by Troy and they're very +long and they're very correct and + + align:start position:0% +long and they're very correct and + + + align:start position:0% +long and they're very correct and +incisive and even if I weren't sick I + + align:start position:0% +incisive and even if I weren't sick I + + + align:start position:0% +incisive and even if I weren't sick I +couldn't cover all those notes so I'm + + align:start position:0% +couldn't cover all those notes so I'm + + + align:start position:0% +couldn't cover all those notes so I'm +going to make a rather Express trip + + align:start position:0% +going to make a rather Express trip + + + align:start position:0% +going to make a rather Express trip +through the notes and the critical thing + + align:start position:0% +through the notes and the critical thing + + + align:start position:0% +through the notes and the critical thing +is we have two electrons and so we can't + + align:start position:0% +is we have two electrons and so we can't + + + align:start position:0% +is we have two electrons and so we can't +simply solve the the problem by using + + align:start position:0% +simply solve the the problem by using + + + align:start position:0% +simply solve the the problem by using +hydrogenic functions although we would + + align:start position:0% +hydrogenic functions although we would + + + align:start position:0% +hydrogenic functions although we would +like to and the crucial thing that is + + align:start position:0% +like to and the crucial thing that is + + + align:start position:0% +like to and the crucial thing that is +missing is you know if if we could + + align:start position:0% +missing is you know if if we could + + + align:start position:0% +missing is you know if if we could +ignore the interactions between the two + + align:start position:0% +ignore the interactions between the two + + + align:start position:0% +ignore the interactions between the two +electrons which are enormous then we + + align:start position:0% +electrons which are enormous then we + + + align:start position:0% +electrons which are enormous then we +would be using hydrogen actions and + + align:start position:0% +would be using hydrogen actions and + + + align:start position:0% +would be using hydrogen actions and +everything would be fine so we can't and + + align:start position:0% +everything would be fine so we can't and + + + align:start position:0% +everything would be fine so we can't and +we use the what's what's called the + + align:start position:0% +we use the what's what's called the + + + align:start position:0% +we use the what's what's called the +independent electron approximation where + + align:start position:0% +independent electron approximation where + + + align:start position:0% +independent electron approximation where +we're still using hydrogenic orbitals + + align:start position:0% +we're still using hydrogenic orbitals + + + align:start position:0% +we're still using hydrogenic orbitals +and energies but we're using those to + + align:start position:0% +and energies but we're using those to + + + align:start position:0% +and energies but we're using those to +include the first order perturbation + + align:start position:0% +include the first order perturbation + + + align:start position:0% +include the first order perturbation +correction to the energies so there's a + + align:start position:0% +correction to the energies so there's a + + + align:start position:0% +correction to the energies so there's a +term the inter inter electron repulsion + + align:start position:0% +term the inter inter electron repulsion + + + align:start position:0% +term the inter inter electron repulsion +that leads to this extra correction + + align:start position:0% +that leads to this extra correction + + + align:start position:0% +that leads to this extra correction +energy and that's most of the difference + + align:start position:0% +energy and that's most of the difference + + + align:start position:0% +energy and that's most of the difference +but then we have identical particles and + + align:start position:0% +but then we have identical particles and + + + align:start position:0% +but then we have identical particles and +when we have identical particles the + + align:start position:0% +when we have identical particles the + + + align:start position:0% +when we have identical particles the +permutation of those two particles has + + align:start position:0% +permutation of those two particles has + + + align:start position:0% +permutation of those two particles has +to commute with the Hamiltonian because + + align:start position:0% +to commute with the Hamiltonian because + + + align:start position:0% +to commute with the Hamiltonian because +the hamiltonian only knows that we're + + align:start position:0% +the hamiltonian only knows that we're + + + align:start position:0% +the hamiltonian only knows that we're +dealing with all the electrons it + + align:start position:0% +dealing with all the electrons it + + + align:start position:0% +dealing with all the electrons it +doesn't put names on the individual + + align:start position:0% +doesn't put names on the individual + + + align:start position:0% +doesn't put names on the individual +electrons and so there's a permutation + + align:start position:0% +electrons and so there's a permutation + + + align:start position:0% +electrons and so there's a permutation +symmetry that has to be imposed and this + + align:start position:0% +symmetry that has to be imposed and this + + + align:start position:0% +symmetry that has to be imposed and this +is very subtle because the permutation + + align:start position:0% +is very subtle because the permutation + + + align:start position:0% +is very subtle because the permutation +symmetry has nothing to do with the + + align:start position:0% +symmetry has nothing to do with the + + + align:start position:0% +symmetry has nothing to do with the +energy but it has to do with the energy + + align:start position:0% +energy but it has to do with the energy + + + align:start position:0% +energy but it has to do with the energy +states and and so we'll explore that now + + align:start position:0% +states and and so we'll explore that now + + + align:start position:0% +states and and so we'll explore that now +since we're going to be dealing with + + align:start position:0% +since we're going to be dealing with + + + align:start position:0% +since we're going to be dealing with +more than one electron there's a lot of + + align:start position:0% +more than one electron there's a lot of + + + align:start position:0% +more than one electron there's a lot of +symbols that we're going to be carrying + + align:start position:0% +symbols that we're going to be carrying + + + align:start position:0% +symbols that we're going to be carrying +around + + align:start position:0% +around + + + align:start position:0% +around +and so there's a useful thing called the + + align:start position:0% +and so there's a useful thing called the + + + align:start position:0% +and so there's a useful thing called the +the atomic units which sets most of the + + align:start position:0% +the atomic units which sets most of the + + + align:start position:0% +the atomic units which sets most of the +physical constants to one and that means + + align:start position:0% +physical constants to one and that means + + + align:start position:0% +physical constants to one and that means +all of the rubble that you have to carry + + align:start position:0% +all of the rubble that you have to carry + + + align:start position:0% +all of the rubble that you have to carry +around goes away and it's not a big deal + + align:start position:0% +around goes away and it's not a big deal + + + align:start position:0% +around goes away and it's not a big deal +because if you use all of the things in + + align:start position:0% +because if you use all of the things in + + + align:start position:0% +because if you use all of the things in +your calculation in atomic units namely + + align:start position:0% +your calculation in atomic units namely + + + align:start position:0% +your calculation in atomic units namely +value 1 or something like 1 then at the + + align:start position:0% +value 1 or something like 1 then at the + + + align:start position:0% +value 1 or something like 1 then at the +end you're going to get the energy in + + align:start position:0% +end you're going to get the energy in + + + align:start position:0% +end you're going to get the energy in +atomic units and we know what that is in + + align:start position:0% +atomic units and we know what that is in + + + align:start position:0% +atomic units and we know what that is in +conventional units so it it it's a risky + + align:start position:0% +conventional units so it it it's a risky + + + align:start position:0% +conventional units so it it it's a risky +thing because you don't really know what + + align:start position:0% +thing because you don't really know what + + + align:start position:0% +thing because you don't really know what +you're doing but at the end you can + + align:start position:0% +you're doing but at the end you can + + + align:start position:0% +you're doing but at the end you can +probably convert your number which is a + + align:start position:0% +probably convert your number which is a + + + align:start position:0% +probably convert your number which is a +pure number into an actual energy ok so + + align:start position:0% +pure number into an actual energy ok so + + + align:start position:0% +pure number into an actual energy ok so +let me start with the good news well + + align:start position:0% +let me start with the good news well + + + align:start position:0% +let me start with the good news well +maybe I should leave this the good news + + align:start position:0% +maybe I should leave this the good news + + + align:start position:0% +maybe I should leave this the good news +is we have two particles for helium the + + align:start position:0% +is we have two particles for helium the + + + align:start position:0% +is we have two particles for helium the +vector R momentum momentum the vector + + align:start position:0% +vector R momentum momentum the vector + + + align:start position:0% +vector R momentum momentum the vector +for particle 1 vector momentum ok so + + align:start position:0% +for particle 1 vector momentum ok so + + + align:start position:0% +for particle 1 vector momentum ok so +these are the actors and when do we have + + align:start position:0% +these are the actors and when do we have + + + align:start position:0% +these are the actors and when do we have +to worry about commutation or non + + align:start position:0% +to worry about commutation or non + + + align:start position:0% +to worry about commutation or non +commutation well the answer is the + + align:start position:0% +commutation well the answer is the + + + align:start position:0% +commutation well the answer is the +coordinates associated with different + + align:start position:0% +coordinates associated with different + + + align:start position:0% +coordinates associated with different +particles they don't haven't they + + align:start position:0% +particles they don't haven't they + + + align:start position:0% +particles they don't haven't they +contribute to the energy but there's no + + align:start position:0% +contribute to the energy but there's no + + + align:start position:0% +contribute to the energy but there's no +problem of commutation the momenta don't + + align:start position:0% +problem of commutation the momenta don't + + + align:start position:0% +problem of commutation the momenta don't +also compute commute the coordinates for + + align:start position:0% +also compute commute the coordinates for + + + align:start position:0% +also compute commute the coordinates for +particle 1 and the momentum for particle + + align:start position:0% +particle 1 and the momentum for particle + + + align:start position:0% +particle 1 and the momentum for particle +2 they commute the only things that + + align:start position:0% +2 they commute the only things that + + + align:start position:0% +2 they commute the only things that +doesn't commute is R 1 X P 1 X those + + align:start position:0% +doesn't commute is R 1 X P 1 X those + + + align:start position:0% +doesn't commute is R 1 X P 1 X those +kinds of things and those are their + + align:start position:0% +kinds of things and those are their + + + align:start position:0% +kinds of things and those are their +commutator is IH bar and that means + + align:start position:0% +commutator is IH bar and that means + + + align:start position:0% +commutator is IH bar and that means +there's some problems so most of the + + align:start position:0% +there's some problems so most of the + + + align:start position:0% +there's some problems so most of the +variables are coming + + align:start position:0% +variables are coming + + + align:start position:0% +variables are coming +variables but some are not and you have + + align:start position:0% +variables but some are not and you have + + + align:start position:0% +variables but some are not and you have +to deal with that okay we know that if + + align:start position:0% +to deal with that okay we know that if + + + align:start position:0% +to deal with that okay we know that if +we have as for example in a three + + align:start position:0% +we have as for example in a three + + + align:start position:0% +we have as for example in a three +dimensional harmonic oscillator if we + + align:start position:0% +dimensional harmonic oscillator if we + + + align:start position:0% +dimensional harmonic oscillator if we +have a Hamiltonian that doesn't commute + + align:start position:0% +have a Hamiltonian that doesn't commute + + + align:start position:0% +have a Hamiltonian that doesn't commute +if we can divide the system up in two + + align:start position:0% +if we can divide the system up in two + + + align:start position:0% +if we can divide the system up in two +parts and the Hamiltonian for each part + + align:start position:0% +parts and the Hamiltonian for each part + + + align:start position:0% +parts and the Hamiltonian for each part +commutes with the Hamiltonian for the + + align:start position:0% +commutes with the Hamiltonian for the + + + align:start position:0% +commutes with the Hamiltonian for the +other part which is part of this then + + align:start position:0% +other part which is part of this then + + + align:start position:0% +other part which is part of this then +the you can write the Hamiltonian as a + + align:start position:0% +the you can write the Hamiltonian as a + + + align:start position:0% +the you can write the Hamiltonian as a +sum of individual system hamiltonians + + align:start position:0% +sum of individual system hamiltonians + + + align:start position:0% +sum of individual system hamiltonians +that could be with each other the + + align:start position:0% +that could be with each other the + + + align:start position:0% +that could be with each other the +energies as the sum and the wave + + align:start position:0% +energies as the sum and the wave + + + align:start position:0% +energies as the sum and the wave +functions is the product and so we like + + align:start position:0% +functions is the product and so we like + + + align:start position:0% +functions is the product and so we like +that and we'd like to be able to build a + + align:start position:0% +that and we'd like to be able to build a + + + align:start position:0% +that and we'd like to be able to build a +picture for helium that is like that and + + align:start position:0% +picture for helium that is like that and + + + align:start position:0% +picture for helium that is like that and +so if we write the Hamiltonian for + + align:start position:0% +so if we write the Hamiltonian for + + + align:start position:0% +so if we write the Hamiltonian for +helium we have P squared for particle 1 + + align:start position:0% +helium we have P squared for particle 1 + + + align:start position:0% +helium we have P squared for particle 1 +over 2m e of B squared I don't know let + + align:start position:0% +over 2m e of B squared I don't know let + + + align:start position:0% +over 2m e of B squared I don't know let +me let me organize better minus Z Z + + align:start position:0% +me let me organize better minus Z Z + + + align:start position:0% +me let me organize better minus Z Z +squared over 4 PI epsilon zero R one and + + align:start position:0% +squared over 4 PI epsilon zero R one and + + + align:start position:0% +squared over 4 PI epsilon zero R one and +then we have another term like this for + + align:start position:0% +then we have another term like this for + + + align:start position:0% +then we have another term like this for +particle two and we can call this + + align:start position:0% +particle two and we can call this + + + align:start position:0% +particle two and we can call this +Hamiltonian one I Hamiltonian one in + + align:start position:0% +Hamiltonian one I Hamiltonian one in + + + align:start position:0% +Hamiltonian one I Hamiltonian one in +this Hamiltonian - and these are + + align:start position:0% +this Hamiltonian - and these are + + + align:start position:0% +this Hamiltonian - and these are +hydrogen atom hamiltonians and we know + + align:start position:0% +hydrogen atom hamiltonians and we know + + + align:start position:0% +hydrogen atom hamiltonians and we know +everything about them so it's a + + align:start position:0% +everything about them so it's a + + + align:start position:0% +everything about them so it's a +fantastic way to build up a basis set + + align:start position:0% +fantastic way to build up a basis set + + + align:start position:0% +fantastic way to build up a basis set +consisting of energy zero order energies + + align:start position:0% +consisting of energy zero order energies + + + align:start position:0% +consisting of energy zero order energies +and zero order wave functions with which + + align:start position:0% +and zero order wave functions with which + + + align:start position:0% +and zero order wave functions with which +we can calculate anything and so then we + + align:start position:0% +we can calculate anything and so then we + + + align:start position:0% +we can calculate anything and so then we +have this one other term which - no plus + + align:start position:0% +have this one other term which - no plus + + + align:start position:0% +have this one other term which - no plus +x squared + + align:start position:0% +x squared + + + align:start position:0% +x squared +over 4pi epsilon 0 / 1 - r are vectors + + align:start position:0% + + + + align:start position:0% + +that's the bad news this says we have a + + align:start position:0% +that's the bad news this says we have a + + + align:start position:0% +that's the bad news this says we have a +Hamiltonian which where we can't use the + + align:start position:0% +Hamiltonian which where we can't use the + + + align:start position:0% +Hamiltonian which where we can't use the +eigenvalues and eigen functions of the + + align:start position:0% +eigenvalues and eigen functions of the + + + align:start position:0% +eigenvalues and eigen functions of the +hydrogenic things unless we do so we can + + align:start position:0% +hydrogenic things unless we do so we can + + + align:start position:0% +hydrogenic things unless we do so we can +say well these give the first-order + + align:start position:0% +say well these give the first-order + + + align:start position:0% +say well these give the first-order +energies for whatever state we want but + + align:start position:0% +energies for whatever state we want but + + + align:start position:0% +energies for whatever state we want but +we can calculate matrix elements of this + + align:start position:0% +we can calculate matrix elements of this + + + align:start position:0% +we can calculate matrix elements of this +term in the basis set associated with + + align:start position:0% +term in the basis set associated with + + + align:start position:0% +term in the basis set associated with +hydrogen and that's fine that's + + align:start position:0% +hydrogen and that's fine that's + + + align:start position:0% +hydrogen and that's fine that's +perfectly good way to calculate the + + align:start position:0% +perfectly good way to calculate the + + + align:start position:0% +perfectly good way to calculate the +first order correction to the energy but + + align:start position:0% +first order correction to the energy but + + + align:start position:0% +first order correction to the energy but +what about this when we do perturbation + + align:start position:0% +what about this when we do perturbation + + + align:start position:0% +what about this when we do perturbation +theory and calculate the second order + + align:start position:0% +theory and calculate the second order + + + align:start position:0% +theory and calculate the second order +corrections to the energy what is that + + align:start position:0% +corrections to the energy what is that + + + align:start position:0% +corrections to the energy what is that +usually made + + align:start position:0% +usually made + + + align:start position:0% +usually made +that's the question clearly enough well + + align:start position:0% +that's the question clearly enough well + + + align:start position:0% +that's the question clearly enough well +you have to do to get these second-order + + align:start position:0% +you have to do to get these second-order + + + align:start position:0% +you have to do to get these second-order +energies in an infinite dimension + + align:start position:0% +energies in an infinite dimension + + + align:start position:0% +energies in an infinite dimension +problem I just gave it away somebody has + + align:start position:0% +problem I just gave it away somebody has + + + align:start position:0% +problem I just gave it away somebody has +to have the courage to to say something + + align:start position:0% +to have the courage to to say something + + + align:start position:0% +to have the courage to to say something +here remember we have a sum and not + + align:start position:0% +here remember we have a sum and not + + + align:start position:0% +here remember we have a sum and not +equal to n from 0 to infinity yeah + + align:start position:0% +equal to n from 0 to infinity yeah + + + align:start position:0% +equal to n from 0 to infinity yeah +that's it you okay I encouraged you so + + align:start position:0% +that's it you okay I encouraged you so + + + align:start position:0% +that's it you okay I encouraged you so +the the way we could use this basis set + + align:start position:0% +the the way we could use this basis set + + + align:start position:0% +the the way we could use this basis set +would be in a perturbation Theory format + + align:start position:0% +would be in a perturbation Theory format + + + align:start position:0% +would be in a perturbation Theory format +is to calculate an infinite number of + + align:start position:0% +is to calculate an infinite number of + + + align:start position:0% +is to calculate an infinite number of +off diagonal matrix elements of the + + align:start position:0% +off diagonal matrix elements of the + + + align:start position:0% +off diagonal matrix elements of the +hydrogenic wave functions and that could + + align:start position:0% +hydrogenic wave functions and that could + + + align:start position:0% +hydrogenic wave functions and that could +yield the results but it's not the way + + align:start position:0% +yield the results but it's not the way + + + align:start position:0% +yield the results but it's not the way +it's done usually there's a variational + + align:start position:0% +it's done usually there's a variational + + + align:start position:0% +it's done usually there's a variational +calculation that you use to get the + + align:start position:0% +calculation that you use to get the + + + align:start position:0% +calculation that you use to get the +better wave functions but we're not + + align:start position:0% +better wave functions but we're not + + + align:start position:0% +better wave functions but we're not +going to do that here we're going to go + + align:start position:0% +going to do that here we're going to go + + + align:start position:0% +going to do that here we're going to go +as far as we can without actually + + align:start position:0% +as far as we can without actually + + + align:start position:0% +as far as we can without actually +addressing what's wrong if we stop here + + align:start position:0% + + + + align:start position:0% + +okay so this guy is h1 the source of all + + align:start position:0% +okay so this guy is h1 the source of all + + + align:start position:0% +okay so this guy is h1 the source of all +trouble and how we deal with it is there + + align:start position:0% +trouble and how we deal with it is there + + + align:start position:0% +trouble and how we deal with it is there +are two steps three steps one is ignore + + align:start position:0% +are two steps three steps one is ignore + + + align:start position:0% +are two steps three steps one is ignore +it the other is use it to calculate use + + align:start position:0% +it the other is use it to calculate use + + + align:start position:0% +it the other is use it to calculate use +our hydrogen ions to calculate matrix + + align:start position:0% +our hydrogen ions to calculate matrix + + + align:start position:0% +our hydrogen ions to calculate matrix +elements of this and and get an h1 + + align:start position:0% +elements of this and and get an h1 + + + align:start position:0% +elements of this and and get an h1 +anyone and the third step would be to + + align:start position:0% +anyone and the third step would be to + + + align:start position:0% +anyone and the third step would be to +get the exact answer by doing an + + align:start position:0% +get the exact answer by doing an + + + align:start position:0% +get the exact answer by doing an +infinitely difficult calculation okay + + align:start position:0% + + + + align:start position:0% + +all right + + align:start position:0% + + + + align:start position:0% + +so this is going to be a notational + + align:start position:0% +so this is going to be a notational + + + align:start position:0% +so this is going to be a notational +voyage which is horrible because there's + + align:start position:0% +voyage which is horrible because there's + + + align:start position:0% +voyage which is horrible because there's +so because we have many particles and + + align:start position:0% +so because we have many particles and + + + align:start position:0% +so because we have many particles and +particles have coordinates and spins + + align:start position:0% +particles have coordinates and spins + + + align:start position:0% +particles have coordinates and spins +we're going to have an explosion of + + align:start position:0% +we're going to have an explosion of + + + align:start position:0% +we're going to have an explosion of +stuff even if we get rid of the + + align:start position:0% +stuff even if we get rid of the + + + align:start position:0% +stuff even if we get rid of the +extraneous units but let's get rid of + + align:start position:0% +extraneous units but let's get rid of + + + align:start position:0% +extraneous units but let's get rid of +the extraneous units and so atomic units + + align:start position:0% + + + + align:start position:0% + +we can choose any internally consistent + + align:start position:0% +we can choose any internally consistent + + + align:start position:0% +we can choose any internally consistent +set of units we want and in atomic units + + align:start position:0% +set of units we want and in atomic units + + + align:start position:0% +set of units we want and in atomic units +we said say that the mass of the + + align:start position:0% +we said say that the mass of the + + + align:start position:0% +we said say that the mass of the +electron is 1 the charge of the electron + + align:start position:0% +electron is 1 the charge of the electron + + + align:start position:0% +electron is 1 the charge of the electron +is 1 the h-bar is 1 4 PI epsilon 0 is 1 + + align:start position:0% +is 1 the h-bar is 1 4 PI epsilon 0 is 1 + + + align:start position:0% +is 1 the h-bar is 1 4 PI epsilon 0 is 1 +that's good + + align:start position:0% +that's good + + + align:start position:0% +that's good +a lot of stuff just gone away ok and the + + align:start position:0% +a lot of stuff just gone away ok and the + + + align:start position:0% +a lot of stuff just gone away ok and the +energy in atomic units is not 1 the + + align:start position:0% +energy in atomic units is not 1 the + + + align:start position:0% +energy in atomic units is not 1 the +energy in atomic units is minus 2 times + + align:start position:0% +energy in atomic units is minus 2 times + + + align:start position:0% +energy in atomic units is minus 2 times +the energy of the hydrogen ik 1s orbital + + align:start position:0% +the energy of the hydrogen ik 1s orbital + + + align:start position:0% +the energy of the hydrogen ik 1s orbital +and that comes out to be 27 point 2 1 + + align:start position:0% +and that comes out to be 27 point 2 1 + + + align:start position:0% +and that comes out to be 27 point 2 1 +electron volts in more convenient units + + align:start position:0% +electron volts in more convenient units + + + align:start position:0% +electron volts in more convenient units +so so you calculate a number and then + + align:start position:0% +so so you calculate a number and then + + + align:start position:0% +so so you calculate a number and then +you multiply it by this to get the real + + align:start position:0% +you multiply it by this to get the real + + + align:start position:0% +you multiply it by this to get the real +energy ok and the unit of length is a0 + + align:start position:0% +energy ok and the unit of length is a0 + + + align:start position:0% +energy ok and the unit of length is a0 +which is the radius of the N equals 1 + + align:start position:0% +which is the radius of the N equals 1 + + + align:start position:0% +which is the radius of the N equals 1 +hydrogenic Bohr orbital or before orbit + + align:start position:0% +hydrogenic Bohr orbital or before orbit + + + align:start position:0% +hydrogenic Bohr orbital or before orbit +and that's 0.5 to 9 angstroms with a lot + + align:start position:0% +and that's 0.5 to 9 angstroms with a lot + + + align:start position:0% +and that's 0.5 to 9 angstroms with a lot +more digits if you need them + + align:start position:0% +more digits if you need them + + + align:start position:0% +more digits if you need them +ok and the speed of light is 137 in + + align:start position:0% +ok and the speed of light is 137 in + + + align:start position:0% +ok and the speed of light is 137 in +atomic units so this you know everything + + align:start position:0% +atomic units so this you know everything + + + align:start position:0% +atomic units so this you know everything +that you're going to need is either 1 or + + align:start position:0% +that you're going to need is either 1 or + + + align:start position:0% +that you're going to need is either 1 or +something that is related to two ok so + + align:start position:0% +something that is related to two ok so + + + align:start position:0% +something that is related to two ok so +you can you can do this and I don't like + + align:start position:0% +you can you can do this and I don't like + + + align:start position:0% +you can you can do this and I don't like +it because it's so easy in a big + + align:start position:0% +it because it's so easy in a big + + + align:start position:0% +it because it's so easy in a big +calculation to get to get your units + + align:start position:0% +calculation to get to get your units + + + align:start position:0% +calculation to get to get your units +screwed up + + align:start position:0% +screwed up + + + align:start position:0% +screwed up +but it's certainly great for lecturing + + align:start position:0% +but it's certainly great for lecturing + + + align:start position:0% +but it's certainly great for lecturing +and perhaps for writing computer + + align:start position:0% +and perhaps for writing computer + + + align:start position:0% +and perhaps for writing computer +programs okay so let's start with a non + + align:start position:0% +programs okay so let's start with a non + + + align:start position:0% +programs okay so let's start with a non +interacting electron or proximation and + + align:start position:0% +interacting electron or proximation and + + + align:start position:0% +interacting electron or proximation and +in the notes it's represented by these + + align:start position:0% +in the notes it's represented by these + + + align:start position:0% +in the notes it's represented by these +letters I don't know whether there's a + + align:start position:0% +letters I don't know whether there's a + + + align:start position:0% +letters I don't know whether there's a +the this is Troy notation or widely + + align:start position:0% +the this is Troy notation or widely + + + align:start position:0% +the this is Troy notation or widely +adopted in quantum chemical circular + + align:start position:0% +adopted in quantum chemical circular + + + align:start position:0% +adopted in quantum chemical circular +circles but so but it's easier to write + + align:start position:0% +circles but so but it's easier to write + + + align:start position:0% +circles but so but it's easier to write +this than that and that just means we're + + align:start position:0% +this than that and that just means we're + + + align:start position:0% +this than that and that just means we're +going to ignore this we just forget + + align:start position:0% +going to ignore this we just forget + + + align:start position:0% +going to ignore this we just forget +about it now we know that's stupid + + align:start position:0% +about it now we know that's stupid + + + align:start position:0% +about it now we know that's stupid +because the electrons have charge of one + + align:start position:0% +because the electrons have charge of one + + + align:start position:0% +because the electrons have charge of one +and they repel each other and the + + align:start position:0% +and they repel each other and the + + + align:start position:0% +and they repel each other and the +nucleus has charge of two in the case of + + align:start position:0% +nucleus has charge of two in the case of + + + align:start position:0% +nucleus has charge of two in the case of +helium and and so we know that the this + + align:start position:0% +helium and and so we know that the this + + + align:start position:0% +helium and and so we know that the this +term is rather similar to H zero and we + + align:start position:0% +term is rather similar to H zero and we + + + align:start position:0% +term is rather similar to H zero and we +can't expect to get very far completely + + align:start position:0% +can't expect to get very far completely + + + align:start position:0% +can't expect to get very far completely +ignoring it but we can do it we can do a + + align:start position:0% +ignoring it but we can do it we can do a + + + align:start position:0% +ignoring it but we can do it we can do a +calculation and we can find out how well + + align:start position:0% +calculation and we can find out how well + + + align:start position:0% +calculation and we can find out how well +it works so and I'm just first of all + + align:start position:0% +it works so and I'm just first of all + + + align:start position:0% +it works so and I'm just first of all +it's clear in the notes and I'm just + + align:start position:0% +it's clear in the notes and I'm just + + + align:start position:0% +it's clear in the notes and I'm just +going to skip to the answer so the + + align:start position:0% +going to skip to the answer so the + + + align:start position:0% +going to skip to the answer so the +energy for helium in the 1s 1s orbital + + align:start position:0% +energy for helium in the 1s 1s orbital + + + align:start position:0% +energy for helium in the 1s 1s orbital +or 1x1 s configuration when we're going + + align:start position:0% +or 1x1 s configuration when we're going + + + align:start position:0% +or 1x1 s configuration when we're going +to use this word configuration what that + + align:start position:0% +to use this word configuration what that + + + align:start position:0% +to use this word configuration what that +means is the list of orbitals that are + + align:start position:0% +means is the list of orbitals that are + + + align:start position:0% +means is the list of orbitals that are +occupied now we're listening principal + + align:start position:0% +occupied now we're listening principal + + + align:start position:0% +occupied now we're listening principal +quantum number and orbital angular + + align:start position:0% +quantum number and orbital angular + + + align:start position:0% +quantum number and orbital angular +momentum there's more stuff which + + align:start position:0% +momentum there's more stuff which + + + align:start position:0% +momentum there's more stuff which +doesn't get listed and that leads to + + align:start position:0% +doesn't get listed and that leads to + + + align:start position:0% +doesn't get listed and that leads to +very interesting stuff but if we have a + + align:start position:0% +very interesting stuff but if we have a + + + align:start position:0% +very interesting stuff but if we have a +list of the orbitals that are occupied + + align:start position:0% +list of the orbitals that are occupied + + + align:start position:0% +list of the orbitals that are occupied +that's called the electronic + + align:start position:0% +that's called the electronic + + + align:start position:0% +that's called the electronic +configuration and I'm an electronic + + align:start position:0% +configuration and I'm an electronic + + + align:start position:0% +configuration and I'm an electronic +spectroscopy so you can be sure the + + align:start position:0% +spectroscopy so you can be sure the + + + align:start position:0% +spectroscopy so you can be sure the +is something I care a lot about so so we + + align:start position:0% +is something I care a lot about so so we + + + align:start position:0% +is something I care a lot about so so we +can calculate this in the hydrogen + + align:start position:0% +can calculate this in the hydrogen + + + align:start position:0% +can calculate this in the hydrogen +acacia sand what you end up getting is + + align:start position:0% +acacia sand what you end up getting is + + + align:start position:0% +acacia sand what you end up getting is +where is it + + align:start position:0% + + + + align:start position:0% + +I'm sorry this is the experimental value + + align:start position:0% +I'm sorry this is the experimental value + + + align:start position:0% +I'm sorry this is the experimental value +Vig the calculated value is C I'm trying + + align:start position:0% +Vig the calculated value is C I'm trying + + + align:start position:0% +Vig the calculated value is C I'm trying +to improve on my notes and in my present + + align:start position:0% +to improve on my notes and in my present + + + align:start position:0% +to improve on my notes and in my present +state I don't make a lot of mistakes so + + align:start position:0% +state I don't make a lot of mistakes so + + + align:start position:0% +state I don't make a lot of mistakes so +that is 108 point 8 electron volts so + + align:start position:0% +that is 108 point 8 electron volts so + + + align:start position:0% +that is 108 point 8 electron volts so +this is the energy of the 1s 1s state + + align:start position:0% +this is the energy of the 1s 1s state + + + align:start position:0% +this is the energy of the 1s 1s state +below the ionization limit so that's + + align:start position:0% +below the ionization limit so that's + + + align:start position:0% +below the ionization limit so that's +what we predict except this is not the + + align:start position:0% +what we predict except this is not the + + + align:start position:0% +what we predict except this is not the +ionization limit this is helium 2 plus + + align:start position:0% +ionization limit this is helium 2 plus + + + align:start position:0% +ionization limit this is helium 2 plus +plus 2 electrons because we use the + + align:start position:0% +plus 2 electrons because we use the + + + align:start position:0% +plus 2 electrons because we use the +energy to ionize both hydrogen atoms and + + align:start position:0% +energy to ionize both hydrogen atoms and + + + align:start position:0% +energy to ionize both hydrogen atoms and +so that so this is 108 point 8 now you + + align:start position:0% +so that so this is 108 point 8 now you + + + align:start position:0% +so that so this is 108 point 8 now you +can measure this experimentally you can + + align:start position:0% +can measure this experimentally you can + + + align:start position:0% +can measure this experimentally you can +do helium helium plus plus electron and + + align:start position:0% +do helium helium plus plus electron and + + + align:start position:0% +do helium helium plus plus electron and +then he then plus going to helium 2 plus + + align:start position:0% +then he then plus going to helium 2 plus + + + align:start position:0% +then he then plus going to helium 2 plus +plus an electron and the observed value + + align:start position:0% +plus an electron and the observed value + + + align:start position:0% +plus an electron and the observed value +is what I wrote before observed is equal + + align:start position:0% +is what I wrote before observed is equal + + + align:start position:0% +is what I wrote before observed is equal +to minus 70 9.0 electron volt well you + + align:start position:0% +to minus 70 9.0 electron volt well you + + + align:start position:0% +to minus 70 9.0 electron volt well you +might say well that's pretty good it's + + align:start position:0% +might say well that's pretty good it's + + + align:start position:0% +might say well that's pretty good it's +the same order of magnitude it's not + + align:start position:0% +the same order of magnitude it's not + + + align:start position:0% +the same order of magnitude it's not +even off by a factor 2 but + + align:start position:0% +even off by a factor 2 but + + + align:start position:0% +even off by a factor 2 but +almost everybody in this room is a + + align:start position:0% +almost everybody in this room is a + + + align:start position:0% +almost everybody in this room is a +chemist and this distance difference + + align:start position:0% +chemist and this distance difference + + + align:start position:0% +chemist and this distance difference +between the the calculated value and the + + align:start position:0% +between the the calculated value and the + + + align:start position:0% +between the the calculated value and the +observed value is 30 electron volts a + + align:start position:0% +observed value is 30 electron volts a + + + align:start position:0% +observed value is 30 electron volts a +chemical bond is typically 5 electron + + align:start position:0% +chemical bond is typically 5 electron + + + align:start position:0% +chemical bond is typically 5 electron +volts so this is totally ridiculous for + + align:start position:0% +volts so this is totally ridiculous for + + + align:start position:0% +volts so this is totally ridiculous for +chemistry we can't use it it we don't + + align:start position:0% +chemistry we can't use it it we don't + + + align:start position:0% +chemistry we can't use it it we don't +even want to think about it because it's + + align:start position:0% +even want to think about it because it's + + + align:start position:0% +even want to think about it because it's +you know it's an order of magnitude away + + align:start position:0% +you know it's an order of magnitude away + + + align:start position:0% +you know it's an order of magnitude away +from what we need so we improve on it by + + align:start position:0% +from what we need so we improve on it by + + + align:start position:0% +from what we need so we improve on it by +including II 1 which is related to H 1 + + align:start position:0% +including II 1 which is related to H 1 + + + align:start position:0% +including II 1 which is related to H 1 +which is that simple looking thing over + + align:start position:0% +which is that simple looking thing over + + + align:start position:0% +which is that simple looking thing over +there so the inner electron repulsions + + align:start position:0% +there so the inner electron repulsions + + + align:start position:0% +there so the inner electron repulsions +can be dealt with not exactly + + align:start position:0% +can be dealt with not exactly + + + align:start position:0% +can be dealt with not exactly +but by calculating diagonal matrix + + align:start position:0% +but by calculating diagonal matrix + + + align:start position:0% +but by calculating diagonal matrix +elements of the inner electronic + + align:start position:0% +elements of the inner electronic + + + align:start position:0% +elements of the inner electronic +electron repulsion and that's what the + + align:start position:0% +electron repulsion and that's what the + + + align:start position:0% +electron repulsion and that's what the +the independent electron approximation + + align:start position:0% +the independent electron approximation + + + align:start position:0% +the independent electron approximation +is so that's all there is but now we + + align:start position:0% +is so that's all there is but now we + + + align:start position:0% +is so that's all there is but now we +bring in something that we hadn't + + align:start position:0% +bring in something that we hadn't + + + align:start position:0% +bring in something that we hadn't +expected would be a problem so we have + + align:start position:0% +expected would be a problem so we have + + + align:start position:0% +expected would be a problem so we have +this mystical or mythical or whatever + + align:start position:0% +this mystical or mythical or whatever + + + align:start position:0% +this mystical or mythical or whatever +operator p1 to operate on some function + + align:start position:0% +operator p1 to operate on some function + + + align:start position:0% +operator p1 to operate on some function +of r1 and r2 and what it does is it + + align:start position:0% +of r1 and r2 and what it does is it + + + align:start position:0% +of r1 and r2 and what it does is it +permutes the electrons we know that if + + align:start position:0% +permutes the electrons we know that if + + + align:start position:0% +permutes the electrons we know that if +something is operating on the names of + + align:start position:0% +something is operating on the names of + + + align:start position:0% +something is operating on the names of +the electrons it has to commute with the + + align:start position:0% +the electrons it has to commute with the + + + align:start position:0% +the electrons it has to commute with the +Hamiltonian so that means that this + + align:start position:0% +Hamiltonian so that means that this + + + align:start position:0% +Hamiltonian so that means that this +operator has to have eigenvalues if if + + align:start position:0% +operator has to have eigenvalues if if + + + align:start position:0% +operator has to have eigenvalues if if +these states are eigenfunctions + + align:start position:0% +these states are eigenfunctions + + + align:start position:0% +these states are eigenfunctions +tonin and there are two possible + + align:start position:0% +tonin and there are two possible + + + align:start position:0% +tonin and there are two possible +eigenvalues because we know P 1 2 + + align:start position:0% +eigenvalues because we know P 1 2 + + + align:start position:0% +eigenvalues because we know P 1 2 +squared on sy is equal to plus so the + + align:start position:0% +squared on sy is equal to plus so the + + + align:start position:0% +squared on sy is equal to plus so the +only way you can do that is having the + + align:start position:0% +only way you can do that is having the + + + align:start position:0% +only way you can do that is having the +eigen value of the permutation operator + + align:start position:0% +eigen value of the permutation operator + + + align:start position:0% +eigen value of the permutation operator +be either plus 1 or minus 1 and this is + + align:start position:0% +be either plus 1 or minus 1 and this is + + + align:start position:0% +be either plus 1 or minus 1 and this is +a fundamental symmetry and it I can't + + align:start position:0% +a fundamental symmetry and it I can't + + + align:start position:0% +a fundamental symmetry and it I can't +possibly tell you where it comes from or + + align:start position:0% +possibly tell you where it comes from or + + + align:start position:0% +possibly tell you where it comes from or +where what I'm about to write on the + + align:start position:0% +where what I'm about to write on the + + + align:start position:0% +where what I'm about to write on the +board comes from but so Oh half f + + align:start position:0% +board comes from but so Oh half f + + + align:start position:0% +board comes from but so Oh half f +integer spins correspond to anti + + align:start position:0% +integer spins correspond to anti + + + align:start position:0% +integer spins correspond to anti +symmetry or belong to the eigenvalue + + align:start position:0% +symmetry or belong to the eigenvalue + + + align:start position:0% +symmetry or belong to the eigenvalue +minus 1 and they're called fermions and + + align:start position:0% +minus 1 and they're called fermions and + + + align:start position:0% +minus 1 and they're called fermions and +integer spins are symmetric with + + align:start position:0% +integer spins are symmetric with + + + align:start position:0% +integer spins are symmetric with +permutation and so integer are symmetric + + align:start position:0% +permutation and so integer are symmetric + + + align:start position:0% +permutation and so integer are symmetric +and they're bosons so we have to write + + align:start position:0% +and they're bosons so we have to write + + + align:start position:0% +and they're bosons so we have to write +wave functions which are wave functions + + align:start position:0% +wave functions which are wave functions + + + align:start position:0% +wave functions which are wave functions +of the electrons which are anti + + align:start position:0% +of the electrons which are anti + + + align:start position:0% +of the electrons which are anti +symmetric with respect to the + + align:start position:0% +symmetric with respect to the + + + align:start position:0% +symmetric with respect to the +permutation of every pair of electrons + + align:start position:0% +permutation of every pair of electrons + + + align:start position:0% +permutation of every pair of electrons +so helium we only have two electrons + + align:start position:0% +so helium we only have two electrons + + + align:start position:0% +so helium we only have two electrons +it's not so bad but any when you when + + align:start position:0% +it's not so bad but any when you when + + + align:start position:0% +it's not so bad but any when you when +you think about something like carbon + + align:start position:0% +you think about something like carbon + + + align:start position:0% +you think about something like carbon +monoxide which I always think about or + + align:start position:0% +monoxide which I always think about or + + + align:start position:0% +monoxide which I always think about or +some other molecule where there's more + + align:start position:0% +some other molecule where there's more + + + align:start position:0% +some other molecule where there's more +than two electrons there's a god-awful + + align:start position:0% +than two electrons there's a god-awful + + + align:start position:0% +than two electrons there's a god-awful +number of permutations and you have to + + align:start position:0% +number of permutations and you have to + + + align:start position:0% +number of permutations and you have to +build them all into the wave function + + align:start position:0% +build them all into the wave function + + + align:start position:0% +build them all into the wave function +and the normal feeling when you hear + + align:start position:0% +and the normal feeling when you hear + + + align:start position:0% +and the normal feeling when you hear +that is oh no I can't possibly imagine + + align:start position:0% +that is oh no I can't possibly imagine + + + align:start position:0% +that is oh no I can't possibly imagine +how to do that and if I could there + + align:start position:0% +how to do that and if I could there + + + align:start position:0% +how to do that and if I could there +would be a ridiculous number of + + align:start position:0% +would be a ridiculous number of + + + align:start position:0% +would be a ridiculous number of +integrals that I would have + + align:start position:0% +integrals that I would have + + + align:start position:0% +integrals that I would have +evaluate and it's true there are a + + align:start position:0% +evaluate and it's true there are a + + + align:start position:0% +evaluate and it's true there are a +ridiculous number of integrals but there + + align:start position:0% +ridiculous number of integrals but there + + + align:start position:0% +ridiculous number of integrals but there +is a simple algebra that enables you how + + align:start position:0% +is a simple algebra that enables you how + + + align:start position:0% +is a simple algebra that enables you how +to deal with them and it involves + + align:start position:0% +to deal with them and it involves + + + align:start position:0% +to deal with them and it involves +creating using what is called Slater + + align:start position:0% +creating using what is called Slater + + + align:start position:0% +creating using what is called Slater +determinant wave functions and I'll talk + + align:start position:0% +determinant wave functions and I'll talk + + + align:start position:0% +determinant wave functions and I'll talk +about that Slater was an MIT professor + + align:start position:0% +about that Slater was an MIT professor + + + align:start position:0% +about that Slater was an MIT professor +he wrote a lot of books and but his + + align:start position:0% +he wrote a lot of books and but his + + + align:start position:0% +he wrote a lot of books and but his +mother thing integer + + align:start position:0% +mother thing integer + + + align:start position:0% +mother thing integer +Oh there's sort of a the-- the the most + + align:start position:0% +Oh there's sort of a the-- the the most + + + align:start position:0% +Oh there's sort of a the-- the the most +important thing he did was to develop + + align:start position:0% +important thing he did was to develop + + + align:start position:0% +important thing he did was to develop +this way of dealing with anti-symmetric + + align:start position:0% +this way of dealing with anti-symmetric + + + align:start position:0% +this way of dealing with anti-symmetric +electronic wave functions so the next + + align:start position:0% +electronic wave functions so the next + + + align:start position:0% +electronic wave functions so the next +thing we have to do is discover how do + + align:start position:0% +thing we have to do is discover how do + + + align:start position:0% +thing we have to do is discover how do +we build symmetric wave functions for + + align:start position:0% +we build symmetric wave functions for + + + align:start position:0% +we build symmetric wave functions for +the simplest possible case where there's + + align:start position:0% +the simplest possible case where there's + + + align:start position:0% +the simplest possible case where there's +two electrons and already we discover + + align:start position:0% +two electrons and already we discover + + + align:start position:0% +two electrons and already we discover +some surprising consequences for this + + align:start position:0% +some surprising consequences for this + + + align:start position:0% +some surprising consequences for this +and so I'm going to go through this but + + align:start position:0% +and so I'm going to go through this but + + + align:start position:0% +and so I'm going to go through this but +I'm going to skip a lot of steps because + + align:start position:0% +I'm going to skip a lot of steps because + + + align:start position:0% +I'm going to skip a lot of steps because +it's so clearly written in the notes and + + align:start position:0% +it's so clearly written in the notes and + + + align:start position:0% +it's so clearly written in the notes and +because we don't really have time to + + align:start position:0% +because we don't really have time to + + + align:start position:0% +because we don't really have time to +deal with fifteen pages of single spaced + + align:start position:0% +deal with fifteen pages of single spaced + + + align:start position:0% +deal with fifteen pages of single spaced +notes and I'm not sufficiently at my + + align:start position:0% +notes and I'm not sufficiently at my + + + align:start position:0% +notes and I'm not sufficiently at my +best to get through maybe twelve and you + + align:start position:0% +best to get through maybe twelve and you + + + align:start position:0% +best to get through maybe twelve and you +don't want that anyway okay so let us + + align:start position:0% +don't want that anyway okay so let us + + + align:start position:0% +don't want that anyway okay so let us +see what what has what happens here and + + align:start position:0% +see what what has what happens here and + + + align:start position:0% +see what what has what happens here and +so let's get to work suppose we have an + + align:start position:0% +so let's get to work suppose we have an + + + align:start position:0% +so let's get to work suppose we have an +electronic state 1s alpha spins we know + + align:start position:0% +electronic state 1s alpha spins we know + + + align:start position:0% +electronic state 1s alpha spins we know +alphas MS equals plus 1/2 and beta is + + align:start position:0% +alphas MS equals plus 1/2 and beta is + + + align:start position:0% +alphas MS equals plus 1/2 and beta is +m/s equals minus 1/2 so this is the + + align:start position:0% +m/s equals minus 1/2 so this is the + + + align:start position:0% +m/s equals minus 1/2 so this is the +spatial coordinate this is the spin + + align:start position:0% +spatial coordinate this is the spin + + + align:start position:0% +spatial coordinate this is the spin +coordinate + + align:start position:0% + + + + align:start position:0% + +okay so here is a simple product of two + + align:start position:0% +okay so here is a simple product of two + + + align:start position:0% +okay so here is a simple product of two +wave functions and we know what they are + + align:start position:0% +wave functions and we know what they are + + + align:start position:0% +wave functions and we know what they are +and so if we apply p1 to this we get + + align:start position:0% +and so if we apply p1 to this we get + + + align:start position:0% +and so if we apply p1 to this we get +side 1s alpha are 2 Sigma 2 s beta R 1 + + align:start position:0% +side 1s alpha are 2 Sigma 2 s beta R 1 + + + align:start position:0% +side 1s alpha are 2 Sigma 2 s beta R 1 +Sigma 1 we don't even know what this is + + align:start position:0% +Sigma 1 we don't even know what this is + + + align:start position:0% +Sigma 1 we don't even know what this is +relative to that so symbolically these + + align:start position:0% +relative to that so symbolically these + + + align:start position:0% +relative to that so symbolically these +are two unrelated quantities so we're + + align:start position:0% +are two unrelated quantities so we're + + + align:start position:0% +are two unrelated quantities so we're +but they are eigenfunctions of the zero + + align:start position:0% +but they are eigenfunctions of the zero + + + align:start position:0% +but they are eigenfunctions of the zero +order Hamiltonian so we can take a + + align:start position:0% +order Hamiltonian so we can take a + + + align:start position:0% +order Hamiltonian so we can take a +linear combination of eigenfunctions + + align:start position:0% +linear combination of eigenfunctions + + + align:start position:0% +linear combination of eigenfunctions +that belong to the same eigenvalue and + + align:start position:0% +that belong to the same eigenvalue and + + + align:start position:0% +that belong to the same eigenvalue and +it's still the same energy so we do that + + align:start position:0% +it's still the same energy so we do that + + + align:start position:0% +it's still the same energy so we do that +and so what we can do is is write a + + align:start position:0% +and so what we can do is is write a + + + align:start position:0% +and so what we can do is is write a +combination of this function and that + + align:start position:0% +combination of this function and that + + + align:start position:0% +combination of this function and that +function and if we do that so now we can + + align:start position:0% +function and if we do that so now we can + + + align:start position:0% +function and if we do that so now we can +have side 1s 2s and what we get is 1 or + + align:start position:0% +have side 1s 2s and what we get is 1 or + + + align:start position:0% +have side 1s 2s and what we get is 1 or +a square root of 2 for normalization and + + align:start position:0% +a square root of 2 for normalization and + + + align:start position:0% +a square root of 2 for normalization and +we have side 1s alpha R 1 Sigma 1 minus + + align:start position:0% +we have side 1s alpha R 1 Sigma 1 minus + + + align:start position:0% +we have side 1s alpha R 1 Sigma 1 minus +sy 1 s beta R 1 R 2 Sigma 2 and this in + + align:start position:0% +sy 1 s beta R 1 R 2 Sigma 2 and this in + + + align:start position:0% +sy 1 s beta R 1 R 2 Sigma 2 and this in +fact is anti-symmetric if you apply the + + align:start position:0% +fact is anti-symmetric if you apply the + + + align:start position:0% +fact is anti-symmetric if you apply the +permutation operator to this it is an + + align:start position:0% +permutation operator to this it is an + + + align:start position:0% +permutation operator to this it is an +anti-symmetric function so this does the + + align:start position:0% +anti-symmetric function so this does the + + + align:start position:0% +anti-symmetric function so this does the +job + + align:start position:0% + + + + align:start position:0% + +now since the hamiltonian doesn't depend + + align:start position:0% +now since the hamiltonian doesn't depend + + + align:start position:0% +now since the hamiltonian doesn't depend +on spin the energy of this state and the + + align:start position:0% +on spin the energy of this state and the + + + align:start position:0% +on spin the energy of this state and the +energy of that state are the same there + + align:start position:0% +energy of that state are the same there + + + align:start position:0% +energy of that state are the same there +hydrogenic and so using this wave + + align:start position:0% +hydrogenic and so using this wave + + + align:start position:0% +hydrogenic and so using this wave +function rather than the individual non + + align:start position:0% +function rather than the individual non + + + align:start position:0% +function rather than the individual non +symmetrized functions doesn't change the + + align:start position:0% +symmetrized functions doesn't change the + + + align:start position:0% +symmetrized functions doesn't change the +energy so are we wasting our time I'm + + align:start position:0% +energy so are we wasting our time I'm + + + align:start position:0% +energy so are we wasting our time I'm +sorry I just want to see what I what I + + align:start position:0% +sorry I just want to see what I what I + + + align:start position:0% +sorry I just want to see what I what I +wrote here so yeah what I wrote is wrong + + align:start position:0% +wrote here so yeah what I wrote is wrong + + + align:start position:0% +wrote here so yeah what I wrote is wrong +1s alpha and we'll just put one in here + + align:start position:0% + + + + align:start position:0% + +1 s beta 2 minus 1s alpha 2 1 s beta 1 + + align:start position:0% +1 s beta 2 minus 1s alpha 2 1 s beta 1 + + + align:start position:0% +1 s beta 2 minus 1s alpha 2 1 s beta 1 +ok this is what I should have written + + align:start position:0% +ok this is what I should have written + + + align:start position:0% +ok this is what I should have written +and this is in fact anti-symmetric thank + + align:start position:0% +and this is in fact anti-symmetric thank + + + align:start position:0% +and this is in fact anti-symmetric thank +you I wrote what's in my notes which is + + align:start position:0% +you I wrote what's in my notes which is + + + align:start position:0% +you I wrote what's in my notes which is +wrong and that's and I didn't realize I + + align:start position:0% +wrong and that's and I didn't realize I + + + align:start position:0% +wrong and that's and I didn't realize I +had done that because I knew the answer + + align:start position:0% +had done that because I knew the answer + + + align:start position:0% +had done that because I knew the answer +all right + + align:start position:0% +all right + + + align:start position:0% +all right +ok so we can use this kind of function + + align:start position:0% +ok so we can use this kind of function + + + align:start position:0% +ok so we can use this kind of function +it's legal because it's an eigenfunction + + align:start position:0% +it's legal because it's an eigenfunction + + + align:start position:0% +it's legal because it's an eigenfunction +of the permutation operator with + + align:start position:0% +of the permutation operator with + + + align:start position:0% +of the permutation operator with +negative symmetry which we're told + + align:start position:0% +negative symmetry which we're told + + + align:start position:0% +negative symmetry which we're told +that's what we have to use for electrons + + align:start position:0% +that's what we have to use for electrons + + + align:start position:0% +that's what we have to use for electrons +I can't tell you where it comes from + + align:start position:0% +I can't tell you where it comes from + + + align:start position:0% +I can't tell you where it comes from +although it came from Pauli and the + + align:start position:0% +although it came from Pauli and the + + + align:start position:0% +although it came from Pauli and the +exclusion principle really is this + + align:start position:0% +exclusion principle really is this + + + align:start position:0% +exclusion principle really is this +rather than what you've memorized its + + align:start position:0% +rather than what you've memorized its + + + align:start position:0% +rather than what you've memorized its +consequence is that you can only put one + + align:start position:0% +consequence is that you can only put one + + + align:start position:0% +consequence is that you can only put one +elect + + align:start position:0% +elect + + + align:start position:0% +elect +on orbital but this is the exclusion + + align:start position:0% +on orbital but this is the exclusion + + + align:start position:0% +on orbital but this is the exclusion +principle and it is poly okay so now we + + align:start position:0% +principle and it is poly okay so now we + + + align:start position:0% +principle and it is poly okay so now we +know what to do and we can calculate the + + align:start position:0% +know what to do and we can calculate the + + + align:start position:0% +know what to do and we can calculate the +matrix elements so i1 s alpha colon 1 s + + align:start position:0% +matrix elements so i1 s alpha colon 1 s + + + align:start position:0% +matrix elements so i1 s alpha colon 1 s +beta this is a product of 2 the anti + + align:start position:0% +beta this is a product of 2 the anti + + + align:start position:0% +beta this is a product of 2 the anti +symmetries product of 2 electrons matrix + + align:start position:0% +symmetries product of 2 electrons matrix + + + align:start position:0% +symmetries product of 2 electrons matrix +element 1 for Hamiltonian 1 plus 1 over + + align:start position:0% +element 1 for Hamiltonian 1 plus 1 over + + + align:start position:0% +element 1 for Hamiltonian 1 plus 1 over +R 1 minus R 2 alpha know this is a + + align:start position:0% +R 1 minus R 2 alpha know this is a + + + align:start position:0% +R 1 minus R 2 alpha know this is a +perfectly legitimate thing to calculate + + align:start position:0% +perfectly legitimate thing to calculate + + + align:start position:0% +perfectly legitimate thing to calculate +we know how to do it or McQuarrie knows + + align:start position:0% +we know how to do it or McQuarrie knows + + + align:start position:0% +we know how to do it or McQuarrie knows +how to do it and you don't really need + + align:start position:0% +how to do it and you don't really need + + + align:start position:0% +how to do it and you don't really need +to worry about doing these integrals + + align:start position:0% +to worry about doing these integrals + + + align:start position:0% +to worry about doing these integrals +because what this is at such a low level + + align:start position:0% +because what this is at such a low level + + + align:start position:0% +because what this is at such a low level +of approximation it does nothing for you + + align:start position:0% +of approximation it does nothing for you + + + align:start position:0% +of approximation it does nothing for you +except teach you how to approach these + + align:start position:0% +except teach you how to approach these + + + align:start position:0% +except teach you how to approach these +problems but we can still do these + + align:start position:0% +problems but we can still do these + + + align:start position:0% +problems but we can still do these +integrals and it's useful so what do you + + align:start position:0% +integrals and it's useful so what do you + + + align:start position:0% +integrals and it's useful so what do you +get when you get minus 4 why because + + align:start position:0% +get when you get minus 4 why because + + + align:start position:0% +get when you get minus 4 why because +these are hydrogenic with a nucleus of + + align:start position:0% +these are hydrogenic with a nucleus of + + + align:start position:0% +these are hydrogenic with a nucleus of +plus 2 and in the atomic units the + + align:start position:0% +plus 2 and in the atomic units the + + + align:start position:0% +plus 2 and in the atomic units the +energy of hydrogen atom to a charge of 1 + + align:start position:0% +energy of hydrogen atom to a charge of 1 + + + align:start position:0% +energy of hydrogen atom to a charge of 1 +is 1/2 not 1 and so and these go as Z + + align:start position:0% +is 1/2 not 1 and so and these go as Z + + + align:start position:0% +is 1/2 not 1 and so and these go as Z +squared so we get 4 over 2 plus 4 over 2 + + align:start position:0% +squared so we get 4 over 2 plus 4 over 2 + + + align:start position:0% +squared so we get 4 over 2 plus 4 over 2 +so we get this minus 4 oh you get - yes + + align:start position:0% +so we get this minus 4 oh you get - yes + + + align:start position:0% +so we get this minus 4 oh you get - yes +and then we get something else and + + align:start position:0% +and then we get something else and + + + align:start position:0% +and then we get something else and +that's this this integral that we look + + align:start position:0% +that's this this integral that we look + + + align:start position:0% +that's this this integral that we look +like which is integral of 1 s alpha beta + + align:start position:0% +like which is integral of 1 s alpha beta + + + align:start position:0% +like which is integral of 1 s alpha beta +squared over R 1 minus R 2 + + align:start position:0% +squared over R 1 minus R 2 + + + align:start position:0% +squared over R 1 minus R 2 +our one the two so we can do this + + align:start position:0% +our one the two so we can do this + + + align:start position:0% +our one the two so we can do this +integral or mr. Macquarie and many of + + align:start position:0% +integral or mr. Macquarie and many of + + + align:start position:0% +integral or mr. Macquarie and many of +his predecessors can do that integral + + align:start position:0% +his predecessors can do that integral + + + align:start position:0% +his predecessors can do that integral +and you get a result and this integral + + align:start position:0% +and you get a result and this integral + + + align:start position:0% +and you get a result and this integral +turns out to be 5z over eight and + + align:start position:0% +turns out to be 5z over eight and + + + align:start position:0% +turns out to be 5z over eight and +converting that into units that we are + + align:start position:0% +converting that into units that we are + + + align:start position:0% +converting that into units that we are +and that's 5/4 au and that's why that + + align:start position:0% +and that's 5/4 au and that's why that + + + align:start position:0% +and that's 5/4 au and that's why that +doesn't seem right + + align:start position:0% +doesn't seem right + + + align:start position:0% +doesn't seem right +anyway it's 34 electron volts or minus + + align:start position:0% +anyway it's 34 electron volts or minus + + + align:start position:0% +anyway it's 34 electron volts or minus +34 electron plus plus 34 electron volts + + align:start position:0% +34 electron plus plus 34 electron volts + + + align:start position:0% +34 electron plus plus 34 electron volts +so the inter electronic repulsion for + + align:start position:0% +so the inter electronic repulsion for + + + align:start position:0% +so the inter electronic repulsion for +hydrogenic orbitals on the same nucleus + + align:start position:0% +hydrogenic orbitals on the same nucleus + + + align:start position:0% +hydrogenic orbitals on the same nucleus +is 34 electoral votes it's a big number + + align:start position:0% +is 34 electoral votes it's a big number + + + align:start position:0% +is 34 electoral votes it's a big number +and so we can correct our observed the + + align:start position:0% +and so we can correct our observed the + + + align:start position:0% +and so we can correct our observed the +calculated vs. observed energy and + + align:start position:0% +calculated vs. observed energy and + + + align:start position:0% +calculated vs. observed energy and +instead of having well the experimental + + align:start position:0% +instead of having well the experimental + + + align:start position:0% +instead of having well the experimental +value is 79 and now the calculated value + + align:start position:0% +value is 79 and now the calculated value + + + align:start position:0% +value is 79 and now the calculated value +is minus seventy four point eight + + align:start position:0% +is minus seventy four point eight + + + align:start position:0% +is minus seventy four point eight +electron volts so this is marginally + + align:start position:0% +electron volts so this is marginally + + + align:start position:0% +electron volts so this is marginally +relevant to chemistry because the error + + align:start position:0% +relevant to chemistry because the error + + + align:start position:0% +relevant to chemistry because the error +is about one of the typical binds bond + + align:start position:0% +is about one of the typical binds bond + + + align:start position:0% +is about one of the typical binds bond +energy and so we can we can do stuff + + align:start position:0% +energy and so we can we can do stuff + + + align:start position:0% +energy and so we can we can do stuff +with this we know that it's not accurate + + align:start position:0% +with this we know that it's not accurate + + + align:start position:0% +with this we know that it's not accurate +enough to do anything quantitative but + + align:start position:0% +enough to do anything quantitative but + + + align:start position:0% +enough to do anything quantitative but +you can use it for qualitative arguments + + align:start position:0% +you can use it for qualitative arguments + + + align:start position:0% +you can use it for qualitative arguments +and we can do much better than this + + align:start position:0% +and we can do much better than this + + + align:start position:0% +and we can do much better than this +using what's going to be called the + + align:start position:0% +using what's going to be called the + + + align:start position:0% +using what's going to be called the +variational principle which is coming + + align:start position:0% + + + + align:start position:0% + +okay so now we're going to be dealing + + align:start position:0% +okay so now we're going to be dealing + + + align:start position:0% +okay so now we're going to be dealing +with a problem that has lots of symbols + + align:start position:0% +with a problem that has lots of symbols + + + align:start position:0% +with a problem that has lots of symbols +and equations and it's best to start + + align:start position:0% +and equations and it's best to start + + + align:start position:0% +and equations and it's best to start +using notation called stick diagrams + + align:start position:0% + + + + align:start position:0% + +because it's completely transparent what + + align:start position:0% +because it's completely transparent what + + + align:start position:0% +because it's completely transparent what +they mean and so it's a shortcut for + + align:start position:0% +they mean and so it's a shortcut for + + + align:start position:0% +they mean and so it's a shortcut for +writing the correct equations so we we + + align:start position:0% +writing the correct equations so we we + + + align:start position:0% +writing the correct equations so we we +have for the ground state of hydrogen + + align:start position:0% +have for the ground state of hydrogen + + + align:start position:0% +have for the ground state of hydrogen +I'm sorry we want to talk about excited + + align:start position:0% +I'm sorry we want to talk about excited + + + align:start position:0% +I'm sorry we want to talk about excited +States because 1s with 1s doesn't have + + align:start position:0% +States because 1s with 1s doesn't have + + + align:start position:0% +States because 1s with 1s doesn't have +enough complexity to attract our + + align:start position:0% +enough complexity to attract our + + + align:start position:0% +enough complexity to attract our +attention and it when we do deal with + + align:start position:0% +attention and it when we do deal with + + + align:start position:0% +attention and it when we do deal with +excited States 1s and 2s we discover + + align:start position:0% +excited States 1s and 2s we discover + + + align:start position:0% +excited States 1s and 2s we discover +something important that's new and it's + + align:start position:0% +something important that's new and it's + + + align:start position:0% +something important that's new and it's +the last thing we really need in order + + align:start position:0% +the last thing we really need in order + + + align:start position:0% +the last thing we really need in order +to understand electronic structure or + + align:start position:0% +to understand electronic structure or + + + align:start position:0% +to understand electronic structure or +how the electronic states that arise + + align:start position:0% +how the electronic states that arise + + + align:start position:0% +how the electronic states that arise +from a configuration are distinguished + + align:start position:0% +from a configuration are distinguished + + + align:start position:0% +from a configuration are distinguished +and so we have for the 1s 2s + + align:start position:0% +and so we have for the 1s 2s + + + align:start position:0% +and so we have for the 1s 2s +configuration there are 4 ways of + + align:start position:0% +configuration there are 4 ways of + + + align:start position:0% +configuration there are 4 ways of +writing this in stick diagrams so we + + align:start position:0% +writing this in stick diagrams so we + + + align:start position:0% +writing this in stick diagrams so we +have 1s 2s and we can have spins up + + align:start position:0% +have 1s 2s and we can have spins up + + + align:start position:0% +have 1s 2s and we can have spins up +alpha alpha and we can have us - we can + + align:start position:0% +alpha alpha and we can have us - we can + + + align:start position:0% +alpha alpha and we can have us - we can +have spins up and down us - it spins + + align:start position:0% +have spins up and down us - it spins + + + align:start position:0% +have spins up and down us - it spins +down and up and 2's what else spins down + + align:start position:0% +down and up and 2's what else spins down + + + align:start position:0% +down and up and 2's what else spins down +so it's much easier to write these + + align:start position:0% +so it's much easier to write these + + + align:start position:0% +so it's much easier to write these +things because they have a + + align:start position:0% +things because they have a + + + align:start position:0% +things because they have a +an equation associated with them and you + + align:start position:0% +an equation associated with them and you + + + align:start position:0% +an equation associated with them and you +can you can play with these symbols so + + align:start position:0% +can you can play with these symbols so + + + align:start position:0% +can you can play with these symbols so +the first thing you notice is this + + align:start position:0% +the first thing you notice is this + + + align:start position:0% +the first thing you notice is this +symbol can be written as an anti + + align:start position:0% +symbol can be written as an anti + + + align:start position:0% +symbol can be written as an anti +symmetrized product and so this symbol + + align:start position:0% +symmetrized product and so this symbol + + + align:start position:0% +symmetrized product and so this symbol +you know we just take the alpha alpha + + align:start position:0% +you know we just take the alpha alpha + + + align:start position:0% +you know we just take the alpha alpha +and so let me just write it out 1 over + + align:start position:0% +and so let me just write it out 1 over + + + align:start position:0% +and so let me just write it out 1 over +square root of 2 times 1 s r1 to s r2 + + align:start position:0% +square root of 2 times 1 s r1 to s r2 + + + align:start position:0% +square root of 2 times 1 s r1 to s r2 +minus so I 1s are - sigh - s r1 and then + + align:start position:0% +minus so I 1s are - sigh - s r1 and then + + + align:start position:0% +minus so I 1s are - sigh - s r1 and then +times a spin part alpha we can just + + align:start position:0% +times a spin part alpha we can just + + + align:start position:0% +times a spin part alpha we can just +abbreviate to 1 and alpha ok so we have + + align:start position:0% +abbreviate to 1 and alpha ok so we have + + + align:start position:0% +abbreviate to 1 and alpha ok so we have +factored the wave function to a spatial + + align:start position:0% +factored the wave function to a spatial + + + align:start position:0% +factored the wave function to a spatial +part and a spin part now I'll make an + + align:start position:0% +part and a spin part now I'll make an + + + align:start position:0% +part and a spin part now I'll make an +outrageous statement doesn't matter how + + align:start position:0% +outrageous statement doesn't matter how + + + align:start position:0% +outrageous statement doesn't matter how +many electrons you'll always be able to + + align:start position:0% +many electrons you'll always be able to + + + align:start position:0% +many electrons you'll always be able to +factor it into a special part and a spin + + align:start position:0% +factor it into a special part and a spin + + + align:start position:0% +factor it into a special part and a spin +part now what is necessary is always + + align:start position:0% +part now what is necessary is always + + + align:start position:0% +part now what is necessary is always +this function that has to be anti + + align:start position:0% +this function that has to be anti + + + align:start position:0% +this function that has to be anti +symmetric and in this case it's the + + align:start position:0% +symmetric and in this case it's the + + + align:start position:0% +symmetric and in this case it's the +spatial part that's anti symmetric and + + align:start position:0% +spatial part that's anti symmetric and + + + align:start position:0% +spatial part that's anti symmetric and +the spin part that's symmetric now when + + align:start position:0% +the spin part that's symmetric now when + + + align:start position:0% +the spin part that's symmetric now when +we try to do these to stick diagrams we + + align:start position:0% +we try to do these to stick diagrams we + + + align:start position:0% +we try to do these to stick diagrams we +cannot write any correct equation for + + align:start position:0% +cannot write any correct equation for + + + align:start position:0% +cannot write any correct equation for +this guy we have to do both of them we + + align:start position:0% +this guy we have to do both of them we + + + align:start position:0% +this guy we have to do both of them we +have to combine the two and that will + + align:start position:0% +have to combine the two and that will + + + align:start position:0% +have to combine the two and that will +give us a separated spin part in spatial + + align:start position:0% +give us a separated spin part in spatial + + + align:start position:0% +give us a separated spin part in spatial +part and it's anti-symmetric you can't + + align:start position:0% +part and it's anti-symmetric you can't + + + align:start position:0% +part and it's anti-symmetric you can't +make an antisymmetric function of this + + align:start position:0% +make an antisymmetric function of this + + + align:start position:0% +make an antisymmetric function of this +just switching the coordinates so + + align:start position:0% +just switching the coordinates so + + + align:start position:0% +just switching the coordinates so +and what you find when you do this is + + align:start position:0% +and what you find when you do this is + + + align:start position:0% +and what you find when you do this is +going to be that we get functions which + + align:start position:0% +going to be that we get functions which + + + align:start position:0% +going to be that we get functions which +look like alpha beta plus or minus beta + + align:start position:0% +look like alpha beta plus or minus beta + + + align:start position:0% +look like alpha beta plus or minus beta +alpha okay so spin one alpha spin to + + align:start position:0% +alpha okay so spin one alpha spin to + + + align:start position:0% +alpha okay so spin one alpha spin to +beta plus or minus spin one beta spin to + + align:start position:0% +beta plus or minus spin one beta spin to + + + align:start position:0% +beta plus or minus spin one beta spin to +alpha and it turns out that there are + + align:start position:0% +alpha and it turns out that there are + + + align:start position:0% +alpha and it turns out that there are +three functions three spin functions + + align:start position:0% +three functions three spin functions + + + align:start position:0% +three functions three spin functions +that we get which are symmetric and all + + align:start position:0% +that we get which are symmetric and all + + + align:start position:0% +that we get which are symmetric and all +three of these are associated with this + + align:start position:0% +three of these are associated with this + + + align:start position:0% +three of these are associated with this +anti-symmetric spatial function they + + align:start position:0% +anti-symmetric spatial function they + + + align:start position:0% +anti-symmetric spatial function they +have the same energy and since there are + + align:start position:0% +have the same energy and since there are + + + align:start position:0% +have the same energy and since there are +three of them we call them a triplet and + + align:start position:0% +three of them we call them a triplet and + + + align:start position:0% +three of them we call them a triplet and +since we're talking about spins this + + align:start position:0% +since we're talking about spins this + + + align:start position:0% +since we're talking about spins this +triplet corresponds to s equals one and + + align:start position:0% +triplet corresponds to s equals one and + + + align:start position:0% +triplet corresponds to s equals one and +you can use s equals one and creation + + align:start position:0% +you can use s equals one and creation + + + align:start position:0% +you can use s equals one and creation +and annihilation operators or raising + + align:start position:0% +and annihilation operators or raising + + + align:start position:0% +and annihilation operators or raising +and lowering operators to show that + + align:start position:0% +and lowering operators to show that + + + align:start position:0% +and lowering operators to show that +these are in fact the three eigenstates + + align:start position:0% +these are in fact the three eigenstates + + + align:start position:0% +these are in fact the three eigenstates +of S sub Z so we call it a triplet + + align:start position:0% +of S sub Z so we call it a triplet + + + align:start position:0% +of S sub Z so we call it a triplet +because they're three of them and it + + align:start position:0% +because they're three of them and it + + + align:start position:0% +because they're three of them and it +also corresponds to s equals one and + + align:start position:0% +also corresponds to s equals one and + + + align:start position:0% +also corresponds to s equals one and +there's one alpha beta minus beta alpha + + align:start position:0% +there's one alpha beta minus beta alpha + + + align:start position:0% +there's one alpha beta minus beta alpha +which is antisymmetric and is associated + + align:start position:0% +which is antisymmetric and is associated + + + align:start position:0% +which is antisymmetric and is associated +with a different spatial function which + + align:start position:0% +with a different spatial function which + + + align:start position:0% +with a different spatial function which +is symmetric and it has to have a + + align:start position:0% +is symmetric and it has to have a + + + align:start position:0% +is symmetric and it has to have a +different energy because the hamiltonian + + align:start position:0% +different energy because the hamiltonian + + + align:start position:0% +different energy because the hamiltonian +operates on the spatial part and not on + + align:start position:0% +operates on the spatial part and not on + + + align:start position:0% +operates on the spatial part and not on +the spin part so anti symmetry has + + align:start position:0% +the spin part so anti symmetry has + + + align:start position:0% +the spin part so anti symmetry has +forced you to have two different spatial + + align:start position:0% +forced you to have two different spatial + + + align:start position:0% +forced you to have two different spatial +wave functions and that guarantees that + + align:start position:0% +wave functions and that guarantees that + + + align:start position:0% +wave functions and that guarantees that +these guys will have different energies + + align:start position:0% +these guys will have different energies + + + align:start position:0% +these guys will have different energies +and since there's only one of them we + + align:start position:0% +and since there's only one of them we + + + align:start position:0% +and since there's only one of them we +call it a singlet and it corresponds to + + align:start position:0% +call it a singlet and it corresponds to + + + align:start position:0% +call it a singlet and it corresponds to +s equals zero so now we want to know + + align:start position:0% +s equals zero so now we want to know + + + align:start position:0% +s equals zero so now we want to know +which is higher in energy the singlet or + + align:start position:0% +which is higher in energy the singlet or + + + align:start position:0% +which is higher in energy the singlet or +the triplet and how much higher + + align:start position:0% +the triplet and how much higher + + + align:start position:0% +the triplet and how much higher +and so again we take the wave functions + + align:start position:0% +and so again we take the wave functions + + + align:start position:0% +and so again we take the wave functions +that are correct as far as permutation + + align:start position:0% +that are correct as far as permutation + + + align:start position:0% +that are correct as far as permutation +is concerned but only approximate as far + + align:start position:0% +is concerned but only approximate as far + + + align:start position:0% +is concerned but only approximate as far +as using hydrogenic functions and we + + align:start position:0% +as using hydrogenic functions and we + + + align:start position:0% +as using hydrogenic functions and we +evaluate the relevant terms in the + + align:start position:0% +evaluate the relevant terms in the + + + align:start position:0% +evaluate the relevant terms in the +Hamiltonian okay so we can forget about + + align:start position:0% +Hamiltonian okay so we can forget about + + + align:start position:0% +Hamiltonian okay so we can forget about +the spin parts now we know we're going + + align:start position:0% +the spin parts now we know we're going + + + align:start position:0% +the spin parts now we know we're going +to have two different spatial wave + + align:start position:0% +to have two different spatial wave + + + align:start position:0% +to have two different spatial wave +functions and we're going to calculate + + align:start position:0% +functions and we're going to calculate + + + align:start position:0% +functions and we're going to calculate +yes that should be I can't here I + + align:start position:0% +yes that should be I can't here I + + + align:start position:0% +yes that should be I can't here I +understand the last word no both spins + + align:start position:0% +understand the last word no both spins + + + align:start position:0% +understand the last word no both spins +up the the vector sum of 1/2 and 1/2 is + + align:start position:0% +up the the vector sum of 1/2 and 1/2 is + + + align:start position:0% +up the the vector sum of 1/2 and 1/2 is +1 and so the total spin is going to be 1 + + align:start position:0% +1 and so the total spin is going to be 1 + + + align:start position:0% +1 and so the total spin is going to be 1 +and it'll and so we have three I mean if + + align:start position:0% +and it'll and so we have three I mean if + + + align:start position:0% +and it'll and so we have three I mean if +we're applying s - stop suppose we start + + align:start position:0% +we're applying s - stop suppose we start + + + align:start position:0% +we're applying s - stop suppose we start +with sorry + + align:start position:0% +with sorry + + + align:start position:0% +with sorry +I I can't hear properly yes it has s + + align:start position:0% +I I can't hear properly yes it has s + + + align:start position:0% +I I can't hear properly yes it has s +equals one okay and now I don't want to + + align:start position:0% +equals one okay and now I don't want to + + + align:start position:0% +equals one okay and now I don't want to +go into the the angular momentum a trick + + align:start position:0% +go into the the angular momentum a trick + + + align:start position:0% +go into the the angular momentum a trick +settlement that would be the last thing + + align:start position:0% +settlement that would be the last thing + + + align:start position:0% +settlement that would be the last thing +in this lecture so yes the projection + + align:start position:0% +in this lecture so yes the projection + + + align:start position:0% +in this lecture so yes the projection +quantum numbers are not uniquely + + align:start position:0% +quantum numbers are not uniquely + + + align:start position:0% +quantum numbers are not uniquely +associated with the total spin but if + + align:start position:0% +associated with the total spin but if + + + align:start position:0% +associated with the total spin but if +you have alpha alpha you can show that + + align:start position:0% +you have alpha alpha you can show that + + + align:start position:0% +you have alpha alpha you can show that +it's s equals one and alpha beta plus + + align:start position:0% +it's s equals one and alpha beta plus + + + align:start position:0% +it's s equals one and alpha beta plus +beta alpha is 1 and beta beta is one but + + align:start position:0% +beta alpha is 1 and beta beta is one but + + + align:start position:0% +beta alpha is 1 and beta beta is one but +alpha beta minus beta alpha is spin zero + + align:start position:0% +alpha beta minus beta alpha is spin zero + + + align:start position:0% +alpha beta minus beta alpha is spin zero +you can do that using creation + + align:start position:0% +you can do that using creation + + + align:start position:0% +you can do that using creation +annihilation operators it's clear okay + + align:start position:0% +annihilation operators it's clear okay + + + align:start position:0% +annihilation operators it's clear okay +so you can't have to take it on faith + + align:start position:0% +so you can't have to take it on faith + + + align:start position:0% +so you can't have to take it on faith +until you prove but I've just said and + + align:start position:0% +until you prove but I've just said and + + + align:start position:0% +until you prove but I've just said and +it takes about two minutes okay so we + + align:start position:0% +it takes about two minutes okay so we + + + align:start position:0% +it takes about two minutes okay so we +can evaluate the integrals and something + + align:start position:0% +can evaluate the integrals and something + + + align:start position:0% +can evaluate the integrals and something +very beautiful occurs and it's done very + + align:start position:0% +very beautiful occurs and it's done very + + + align:start position:0% +very beautiful occurs and it's done very +very clearly in the notes and it would + + align:start position:0% +very clearly in the notes and it would + + + align:start position:0% +very clearly in the notes and it would +take me more time do we have left to do + + align:start position:0% +take me more time do we have left to do + + + align:start position:0% +take me more time do we have left to do +it and I didn't plan on do it anyway so + + align:start position:0% +it and I didn't plan on do it anyway so + + + align:start position:0% +it and I didn't plan on do it anyway so +we get the energies for the singlet and + + align:start position:0% +we get the energies for the singlet and + + + align:start position:0% +we get the energies for the singlet and +triplet states which are B 1 s plus e 2 + + align:start position:0% +triplet states which are B 1 s plus e 2 + + + align:start position:0% +triplet states which are B 1 s plus e 2 +s now remember these are for a 1s + + align:start position:0% +s now remember these are for a 1s + + + align:start position:0% +s now remember these are for a 1s +orbital on helium so it's going to be + + align:start position:0% +orbital on helium so it's going to be + + + align:start position:0% +orbital on helium so it's going to be +four times the energy of the 1s orbital + + align:start position:0% +four times the energy of the 1s orbital + + + align:start position:0% +four times the energy of the 1s orbital +of hydrogen but we know what they are + + align:start position:0% +of hydrogen but we know what they are + + + align:start position:0% +of hydrogen but we know what they are +plus what we call J 1s 2s plus or minus + + align:start position:0% +plus what we call J 1s 2s plus or minus + + + align:start position:0% +plus what we call J 1s 2s plus or minus +K 1s + + align:start position:0% +K 1s + + + align:start position:0% +K 1s +yes so this is clear and the integral + + align:start position:0% +yes so this is clear and the integral + + + align:start position:0% +yes so this is clear and the integral +associated with this is taking the + + align:start position:0% +associated with this is taking the + + + align:start position:0% +associated with this is taking the +square of the wave function and + + align:start position:0% +square of the wave function and + + + align:start position:0% +square of the wave function and +basically we're evaluating the + + align:start position:0% +basically we're evaluating the + + + align:start position:0% +basically we're evaluating the +interaction between an electron 1 in the + + align:start position:0% +interaction between an electron 1 in the + + + align:start position:0% +interaction between an electron 1 in the +1s orbital + + align:start position:0% +1s orbital + + + align:start position:0% +1s orbital +an electron to in the 2's orbital so + + align:start position:0% +an electron to in the 2's orbital so + + + align:start position:0% +an electron to in the 2's orbital so +that's a perfectly doable thing it's a + + align:start position:0% +that's a perfectly doable thing it's a + + + align:start position:0% +that's a perfectly doable thing it's a +classical quantity we have to charge + + align:start position:0% +classical quantity we have to charge + + + align:start position:0% +classical quantity we have to charge +distributions and we're calculating the + + align:start position:0% +distributions and we're calculating the + + + align:start position:0% +distributions and we're calculating the +energy interaction between two electrons + + align:start position:0% +energy interaction between two electrons + + + align:start position:0% +energy interaction between two electrons +in these two charge distributions so + + align:start position:0% +in these two charge distributions so + + + align:start position:0% +in these two charge distributions so +this is called the Coulomb integral and + + align:start position:0% +this is called the Coulomb integral and + + + align:start position:0% +this is called the Coulomb integral and +that is an entirely classical quantity + + align:start position:0% +that is an entirely classical quantity + + + align:start position:0% +that is an entirely classical quantity +and this is called the exchange integral + + align:start position:0% +and this is called the exchange integral + + + align:start position:0% +and this is called the exchange integral +and the reason we call it an exchange + + align:start position:0% +and the reason we call it an exchange + + + align:start position:0% +and the reason we call it an exchange +integral is basically we're switching + + align:start position:0% +integral is basically we're switching + + + align:start position:0% +integral is basically we're switching +the electrons between these two orbitals + + align:start position:0% +the electrons between these two orbitals + + + align:start position:0% +the electrons between these two orbitals +and this is something which is entirely + + align:start position:0% +and this is something which is entirely + + + align:start position:0% +and this is something which is entirely +quantum mechanical it comes about + + align:start position:0% +quantum mechanical it comes about + + + align:start position:0% +quantum mechanical it comes about +because of the permutation symmetry + + align:start position:0% +because of the permutation symmetry + + + align:start position:0% +because of the permutation symmetry +that's required for fermions + + align:start position:0% +that's required for fermions + + + align:start position:0% +that's required for fermions +and so this is the surprise and it's + + align:start position:0% +and so this is the surprise and it's + + + align:start position:0% +and so this is the surprise and it's +also depends on the size whether you + + align:start position:0% +also depends on the size whether you + + + align:start position:0% +also depends on the size whether you +have a symmetric or an anti-symmetric or + + align:start position:0% +have a symmetric or an anti-symmetric or + + + align:start position:0% +have a symmetric or an anti-symmetric or +a singlet or a triplet and so you end up + + align:start position:0% +a singlet or a triplet and so you end up + + + align:start position:0% +a singlet or a triplet and so you end up +getting an energy level diagram for the + + align:start position:0% +getting an energy level diagram for the + + + align:start position:0% +getting an energy level diagram for the +snakes of a configuration which looks + + align:start position:0% +snakes of a configuration which looks + + + align:start position:0% +snakes of a configuration which looks +like this so we start out with a 0 1s 2s + + align:start position:0% +like this so we start out with a 0 1s 2s + + + align:start position:0% +like this so we start out with a 0 1s 2s +and then we allow the charge + + align:start position:0% +and then we allow the charge + + + align:start position:0% +and then we allow the charge +distributions to interact and the + + align:start position:0% +distributions to interact and the + + + align:start position:0% +distributions to interact and the +electrons are going to repel each other + + align:start position:0% +electrons are going to repel each other + + + align:start position:0% +electrons are going to repel each other +it's a positive energy and so this is e0 + + align:start position:0% +it's a positive energy and so this is e0 + + + align:start position:0% +it's a positive energy and so this is e0 +plus J and then we include the exchange + + align:start position:0% +plus J and then we include the exchange + + + align:start position:0% +plus J and then we include the exchange +interaction and so this is the + + align:start position:0% +interaction and so this is the + + + align:start position:0% +interaction and so this is the +difference 2 K and this is e 0 plus J + + align:start position:0% +difference 2 K and this is e 0 plus J + + + align:start position:0% +difference 2 K and this is e 0 plus J +plus K and this is e 0 plus J minus K + + align:start position:0% +plus K and this is e 0 plus J minus K + + + align:start position:0% +plus K and this is e 0 plus J minus K +and this is the singlet state as a + + align:start position:0% +and this is the singlet state as a + + + align:start position:0% +and this is the singlet state as a +triplet state and this is a singlet and + + align:start position:0% +triplet state and this is a singlet and + + + align:start position:0% +triplet state and this is a singlet and +for helium we called the singlet state + + align:start position:0% +for helium we called the singlet state + + + align:start position:0% +for helium we called the singlet state +singlet s because total angular momentum + + align:start position:0% +singlet s because total angular momentum + + + align:start position:0% +singlet s because total angular momentum +is 0 and spin has zero and the triplet + + align:start position:0% +is 0 and spin has zero and the triplet + + + align:start position:0% +is 0 and spin has zero and the triplet +we call it triplet us now if + + align:start position:0% +we call it triplet us now if + + + align:start position:0% +we call it triplet us now if +we did one s2p we would get singlet and + + align:start position:0% +we did one s2p we would get singlet and + + + align:start position:0% +we did one s2p we would get singlet and +triplet P states but the important thing + + align:start position:0% +triplet P states but the important thing + + + align:start position:0% +triplet P states but the important thing +is how big is K and remember K is an + + align:start position:0% +is how big is K and remember K is an + + + align:start position:0% +is how big is K and remember K is an +approximation it's it's a real quantity + + align:start position:0% +approximation it's it's a real quantity + + + align:start position:0% +approximation it's it's a real quantity +but for hydrogenic orbitals is going to + + align:start position:0% +but for hydrogenic orbitals is going to + + + align:start position:0% +but for hydrogenic orbitals is going to +be incorrect and so two k12 is 2.4 + + align:start position:0% +be incorrect and so two k12 is 2.4 + + + align:start position:0% +be incorrect and so two k12 is 2.4 +electron volts and that's a perfectly + + align:start position:0% +electron volts and that's a perfectly + + + align:start position:0% +electron volts and that's a perfectly +doable calculation because you're + + align:start position:0% +doable calculation because you're + + + align:start position:0% +doable calculation because you're +dealing with simple functions and you + + align:start position:0% +dealing with simple functions and you + + + align:start position:0% +dealing with simple functions and you +can do this integral and you can + + align:start position:0% +can do this integral and you can + + + align:start position:0% +can do this integral and you can +actually do it in closed form but it's + + align:start position:0% +actually do it in closed form but it's + + + align:start position:0% +actually do it in closed form but it's +2.4 electron volts and experiment + + align:start position:0% + + + + align:start position:0% + +it's 0.8 and this tells you something + + align:start position:0% +it's 0.8 and this tells you something + + + align:start position:0% +it's 0.8 and this tells you something +really important the repulsion between + + align:start position:0% +really important the repulsion between + + + align:start position:0% +really important the repulsion between +two electrons when you have the correct + + align:start position:0% +two electrons when you have the correct + + + align:start position:0% +two electrons when you have the correct +wave function is less than it would be + + align:start position:0% +wave function is less than it would be + + + align:start position:0% +wave function is less than it would be +if you're using the wrong wave functions + + align:start position:0% +if you're using the wrong wave functions + + + align:start position:0% +if you're using the wrong wave functions +and basically whenever you do anything + + align:start position:0% +and basically whenever you do anything + + + align:start position:0% +and basically whenever you do anything +using the wrong wave functions your + + align:start position:0% +using the wrong wave functions your + + + align:start position:0% +using the wrong wave functions your +energy levels are too large or the + + align:start position:0% +energy levels are too large or the + + + align:start position:0% +energy levels are too large or the +energy differences are too large and in + + align:start position:0% +energy differences are too large and in + + + align:start position:0% +energy differences are too large and in +this case the electrons and when you + + align:start position:0% +this case the electrons and when you + + + align:start position:0% +this case the electrons and when you +solve the exact Schrodinger equation the + + align:start position:0% +solve the exact Schrodinger equation the + + + align:start position:0% +solve the exact Schrodinger equation the +electrons know about how to absorb and + + align:start position:0% +electrons know about how to absorb and + + + align:start position:0% +electrons know about how to absorb and +to avoid each other + + align:start position:0% +to avoid each other + + + align:start position:0% +to avoid each other +it's called correlation energy and this + + align:start position:0% +it's called correlation energy and this + + + align:start position:0% +it's called correlation energy and this +is what makes all the calculations hard + + align:start position:0% +is what makes all the calculations hard + + + align:start position:0% +is what makes all the calculations hard +because there is no closed form analytic + + align:start position:0% +because there is no closed form analytic + + + align:start position:0% +because there is no closed form analytic +expression for the correlation energy + + align:start position:0% +expression for the correlation energy + + + align:start position:0% +expression for the correlation energy +and the way you minimize the correlation + + align:start position:0% +and the way you minimize the correlation + + + align:start position:0% +and the way you minimize the correlation +correlation that are you optimize the + + align:start position:0% +correlation that are you optimize the + + + align:start position:0% +correlation that are you optimize the +correlation energy is throwing a huge + + align:start position:0% +correlation energy is throwing a huge + + + align:start position:0% +correlation energy is throwing a huge +basis set at the problem and this is why + + align:start position:0% +basis set at the problem and this is why + + + align:start position:0% +basis set at the problem and this is why +it takes so long and you never know that + + align:start position:0% +it takes so long and you never know that + + + align:start position:0% +it takes so long and you never know that +you've converged until you've thrown + + align:start position:0% +you've converged until you've thrown + + + align:start position:0% +you've converged until you've thrown +another million functions ok but so + + align:start position:0% +another million functions ok but so + + + align:start position:0% +another million functions ok but so +there's several lessons and that is + + align:start position:0% +there's several lessons and that is + + + align:start position:0% +there's several lessons and that is +we have something that's completely + + align:start position:0% +we have something that's completely + + + align:start position:0% +we have something that's completely +classical and we understand what it is + + align:start position:0% +classical and we understand what it is + + + align:start position:0% +classical and we understand what it is +and then we have this extra thing that + + align:start position:0% +and then we have this extra thing that + + + align:start position:0% +and then we have this extra thing that +is a consequence of the permutation + + align:start position:0% +is a consequence of the permutation + + + align:start position:0% +is a consequence of the permutation +symmetry and so this extra thing is we + + align:start position:0% +symmetry and so this extra thing is we + + + align:start position:0% +symmetry and so this extra thing is we +calculate it too big but it sells says + + align:start position:0% +calculate it too big but it sells says + + + align:start position:0% +calculate it too big but it sells says +that if we have states that belong to + + align:start position:0% +that if we have states that belong to + + + align:start position:0% +that if we have states that belong to +the same electronic configuration in + + align:start position:0% +the same electronic configuration in + + + align:start position:0% +the same electronic configuration in +other words if we specify the orbitals + + align:start position:0% +other words if we specify the orbitals + + + align:start position:0% +other words if we specify the orbitals +that are occupied there's going to be + + align:start position:0% +that are occupied there's going to be + + + align:start position:0% +that are occupied there's going to be +more than one electronic state and so + + align:start position:0% +more than one electronic state and so + + + align:start position:0% +more than one electronic state and so +configuration split into many different + + align:start position:0% +configuration split into many different + + + align:start position:0% +configuration split into many different +electronic states and we know the + + align:start position:0% +electronic states and we know the + + + align:start position:0% +electronic states and we know the +machinery that enables us to calculate + + align:start position:0% +machinery that enables us to calculate + + + align:start position:0% +machinery that enables us to calculate +their relative energies and some of it + + align:start position:0% +their relative energies and some of it + + + align:start position:0% +their relative energies and some of it +is simple Coulomb's law and some of it + + align:start position:0% +is simple Coulomb's law and some of it + + + align:start position:0% +is simple Coulomb's law and some of it +is something that's caused by the + + align:start position:0% +is something that's caused by the + + + align:start position:0% +is something that's caused by the +required permutation symmetry so I'm I'm + + align:start position:0% +required permutation symmetry so I'm I'm + + + align:start position:0% +required permutation symmetry so I'm I'm +over time but this is I really I can't + + align:start position:0% +over time but this is I really I can't + + + align:start position:0% +over time but this is I really I can't +believe that I got to this point because + + align:start position:0% +believe that I got to this point because + + + align:start position:0% +believe that I got to this point because +that I delivered everything that was + + align:start position:0% +that I delivered everything that was + + + align:start position:0% +that I delivered everything that was +really important when we have more than + + align:start position:0% +really important when we have more than + + + align:start position:0% +really important when we have more than +two electrons everything I've said is + + align:start position:0% +two electrons everything I've said is + + + align:start position:0% +two electrons everything I've said is +true it's just more complicated and we + + align:start position:0% +true it's just more complicated and we + + + align:start position:0% +true it's just more complicated and we +have to evaluate matrix elements between + + align:start position:0% +have to evaluate matrix elements between + + + align:start position:0% +have to evaluate matrix elements between +determinantal wave functions which looks + + align:start position:0% +determinantal wave functions which looks + + + align:start position:0% +determinantal wave functions which looks +like you know if you have n electrons + + align:start position:0% +like you know if you have n electrons + + + align:start position:0% +like you know if you have n electrons +there's n factorial terms in a + + align:start position:0% +there's n factorial terms in a + + + align:start position:0% +there's n factorial terms in a +determinant and we have n factorial + + align:start position:0% +determinant and we have n factorial + + + align:start position:0% +determinant and we have n factorial +squared matrix elements and you don't + + align:start position:0% +squared matrix elements and you don't + + + align:start position:0% +squared matrix elements and you don't +want to do that but there turns out to + + align:start position:0% +want to do that but there turns out to + + + align:start position:0% +want to do that but there turns out to +be a simple algebra that makes it all + + align:start position:0% +be a simple algebra that makes it all + + + align:start position:0% +be a simple algebra that makes it all +pop out almost with the same level of + + align:start position:0% +pop out almost with the same level of + + + align:start position:0% +pop out almost with the same level of +effort as this and so we'll talk about + + align:start position:0% +effort as this and so we'll talk about + + + align:start position:0% +effort as this and so we'll talk about +many electron atoms and then we'll go on + + align:start position:0% +many electron atoms and then we'll go on + + + align:start position:0% +many electron atoms and then we'll go on +to molecules after the many electron + + align:start position:0% +to molecules after the many electron + + + align:start position:0% +to molecules after the many electron +atoms lecture ok \ No newline at end of file diff --git a/Du9eDHwGeAw.txt b/Du9eDHwGeAw.txt new file mode 100644 index 0000000000000000000000000000000000000000..60e3fda372cc87416a8280047756c52dee195c03 --- /dev/null +++ b/Du9eDHwGeAw.txt @@ -0,0 +1,2984 @@ +align:start position:0% + +it's time for step two what don't we + + align:start position:0% +it's time for step two what don't we + + + align:start position:0% +it's time for step two what don't we +know here well we don't know anything + + align:start position:0% +know here well we don't know anything + + + align:start position:0% +know here well we don't know anything +about the state correction so and one + + align:start position:0% +about the state correction so and one + + + align:start position:0% +about the state correction so and one +what is in one so step two is find the + + align:start position:0% +what is in one so step two is find the + + + align:start position:0% +what is in one so step two is find the +piece of n1k the piece that is in the + + align:start position:0% +piece of n1k the piece that is in the + + + align:start position:0% +piece of n1k the piece that is in the +space be hot so I will use this notation + + align:start position:0% +space be hot so I will use this notation + + + align:start position:0% +space be hot so I will use this notation +a bar here saying of this vector the + + align:start position:0% +a bar here saying of this vector the + + + align:start position:0% +a bar here saying of this vector the +piece in that subspace then we of course + + align:start position:0% +piece in that subspace then we of course + + + align:start position:0% +piece in that subspace then we of course +need to find the piece in the degenerate + + align:start position:0% +need to find the piece in the degenerate + + + align:start position:0% +need to find the piece in the degenerate +subspace remember the corrections are + + align:start position:0% +subspace remember the corrections are + + + align:start position:0% +subspace remember the corrections are +orthogonal to the original state but the + + align:start position:0% +orthogonal to the original state but the + + + align:start position:0% +orthogonal to the original state but the +corrections have can have a piece on VM + + align:start position:0% +corrections have can have a piece on VM + + + align:start position:0% +corrections have can have a piece on VM +the VM has more state so it can't have a + + align:start position:0% +the VM has more state so it can't have a + + + align:start position:0% +the VM has more state so it can't have a +piece in Vienna and that's typically the + + align:start position:0% +piece in Vienna and that's typically the + + + align:start position:0% +piece in Vienna and that's typically the +part that is a little hard to do so what + + align:start position:0% +part that is a little hard to do so what + + + align:start position:0% +part that is a little hard to do so what +do we do here we take the order one + + align:start position:0% +do we do here we take the order one + + + align:start position:0% +do we do here we take the order one +equation lambda equal one and we hit it + + align:start position:0% +equation lambda equal one and we hit it + + + align:start position:0% +equation lambda equal one and we hit it +with peanut so we'll hit with peanut on + + align:start position:0% +with peanut so we'll hit with peanut on + + + align:start position:0% +with peanut so we'll hit with peanut on +the order lambda equation okay so think + + align:start position:0% +the order lambda equation okay so think + + + align:start position:0% +the order lambda equation okay so think +of the peanut vector + + align:start position:0% +of the peanut vector + + + align:start position:0% +of the peanut vector +bra appearing here we know the energy of + + align:start position:0% +bra appearing here we know the energy of + + + align:start position:0% +bra appearing here we know the energy of +it so this will become a number so we + + align:start position:0% +it so this will become a number so we + + + align:start position:0% +it so this will become a number so we +get EP 0 minus e n 0 P naught and 1k + + align:start position:0% + + + + align:start position:0% + +and indeed when you see here you say oh + + align:start position:0% +and indeed when you see here you say oh + + + align:start position:0% +and indeed when you see here you say oh +this is my unknown I don't know the + + align:start position:0% +this is my unknown I don't know the + + + align:start position:0% +this is my unknown I don't know the +first order correction and I'm getting + + align:start position:0% +first order correction and I'm getting + + + align:start position:0% +first order correction and I'm getting +the components of this unknown + + align:start position:0% +the components of this unknown + + + align:start position:0% +the components of this unknown +correction along with V hat space that's + + align:start position:0% +correction along with V hat space that's + + + align:start position:0% +correction along with V hat space that's +why this calculation can only give me + + align:start position:0% +why this calculation can only give me + + + align:start position:0% +why this calculation can only give me +the piece of n1 k along the hat and then + + align:start position:0% +the piece of n1 k along the hat and then + + + align:start position:0% +the piece of n1 k along the hat and then +what do we have here we have P naught e + + align:start position:0% + + + + align:start position:0% + +NK 1 minus Delta H and 0 K it's just + + align:start position:0% +NK 1 minus Delta H and 0 K it's just + + + align:start position:0% +NK 1 minus Delta H and 0 K it's just +that order one equation calculated here + + align:start position:0% +that order one equation calculated here + + + align:start position:0% +that order one equation calculated here +so what is you know you recognize the + + align:start position:0% +so what is you know you recognize the + + + align:start position:0% +so what is you know you recognize the +challenge here is always sort of trying + + align:start position:0% +challenge here is always sort of trying + + + align:start position:0% +challenge here is always sort of trying +to remember what the symbols mean and + + align:start position:0% +to remember what the symbols mean and + + + align:start position:0% +to remember what the symbols mean and +simplify things so for example here this + + align:start position:0% +simplify things so for example here this + + + align:start position:0% +simplify things so for example here this +is a number so what you must ask is + + align:start position:0% +is a number so what you must ask is + + + align:start position:0% +is a number so what you must ask is +whether this vector is orthogonal to + + align:start position:0% +whether this vector is orthogonal to + + + align:start position:0% +whether this vector is orthogonal to +this one because you're gonna get an + + align:start position:0% +this one because you're gonna get an + + + align:start position:0% +this one because you're gonna get an +inner product and this is a vector in V + + align:start position:0% +inner product and this is a vector in V + + + align:start position:0% +inner product and this is a vector in V +hat and this is a vector in V capital n + + align:start position:0% +hat and this is a vector in V capital n + + + align:start position:0% +hat and this is a vector in V capital n +so therefore they are orthogonal so this + + align:start position:0% +so therefore they are orthogonal so this + + + align:start position:0% +so therefore they are orthogonal so this +term vanishes by orthogonal ax T of + + align:start position:0% +term vanishes by orthogonal ax T of + + + align:start position:0% +term vanishes by orthogonal ax T of +these two on the other hand we are left + + align:start position:0% +these two on the other hand we are left + + + align:start position:0% +these two on the other hand we are left +with this part here now that's a matrix + + align:start position:0% +with this part here now that's a matrix + + + align:start position:0% +with this part here now that's a matrix +element of Delta H between the generate + + align:start position:0% +element of Delta H between the generate + + + align:start position:0% +element of Delta H between the generate +state and then the rest of the state so + + align:start position:0% +state and then the rest of the state so + + + align:start position:0% +state and then the rest of the state so +that's something you have to calculate + + align:start position:0% +that's something you have to calculate + + + align:start position:0% +that's something you have to calculate +there's no way around it so we use our + + align:start position:0% +there's no way around it so we use our + + + align:start position:0% +there's no way around it so we use our +notation and in our notation this would + + align:start position:0% +notation and in our notation this would + + + align:start position:0% +notation and in our notation this would +be Delta H P and K all right so this + + align:start position:0% +be Delta H P and K all right so this + + + align:start position:0% +be Delta H P and K all right so this +gives us we're done with this equation + + align:start position:0% +gives us we're done with this equation + + + align:start position:0% +gives us we're done with this equation +it was simple no no big sweat we now + + align:start position:0% +it was simple no no big sweat we now + + + align:start position:0% +it was simple no no big sweat we now +have these coefficients because these + + align:start position:0% +have these coefficients because these + + + align:start position:0% +have these coefficients because these +are numbers and we can just divide over + + align:start position:0% +are numbers and we can just divide over + + + align:start position:0% +are numbers and we can just divide over +here and + + align:start position:0% +here and + + + align:start position:0% +here and +and this factor is nonzero because all + + align:start position:0% +and this factor is nonzero because all + + + align:start position:0% +and this factor is nonzero because all +the peace states that are in we have + + align:start position:0% +the peace states that are in we have + + + align:start position:0% +the peace states that are in we have +have different energy from our + + align:start position:0% +have different energy from our + + + align:start position:0% +have different energy from our +degenerate ones so there are the + + align:start position:0% +degenerate ones so there are the + + + align:start position:0% +degenerate ones so there are the +components of this so we have p 0 and 1 + + align:start position:0% +components of this so we have p 0 and 1 + + + align:start position:0% +components of this so we have p 0 and 1 +k is equal to minus delta h p NK divided + + align:start position:0% +k is equal to minus delta h p NK divided + + + align:start position:0% +k is equal to minus delta h p NK divided +by this quantity p 0 minus e m 0 and + + align:start position:0% +by this quantity p 0 minus e m 0 and + + + align:start position:0% +by this quantity p 0 minus e m 0 and +therefore we can write n 1 k if you have + + align:start position:0% +therefore we can write n 1 k if you have + + + align:start position:0% +therefore we can write n 1 k if you have +the inner products of a state with p + + align:start position:0% +the inner products of a state with p + + + align:start position:0% +the inner products of a state with p +arbitrary the state is the sum of over + + align:start position:0% +arbitrary the state is the sum of over + + + align:start position:0% +arbitrary the state is the sum of over +piece times that inner product so i'll + + align:start position:0% +piece times that inner product so i'll + + + align:start position:0% +piece times that inner product so i'll +write it as minus because of that minus + + align:start position:0% +write it as minus because of that minus + + + align:start position:0% +write it as minus because of that minus +here the sum over P of Delta H P and K + + align:start position:0% +here the sum over P of Delta H P and K + + + align:start position:0% +here the sum over P of Delta H P and K +over EP 0 minus a 0 T 0 written like + + align:start position:0% +over EP 0 minus a 0 T 0 written like + + + align:start position:0% +over EP 0 minus a 0 T 0 written like +that this is something you know maybe it + + align:start position:0% +that this is something you know maybe it + + + align:start position:0% +that this is something you know maybe it +sounds a little fast but if you have a + + align:start position:0% +sounds a little fast but if you have a + + + align:start position:0% +sounds a little fast but if you have a +basis vector alpha I with sy being the + + align:start position:0% +basis vector alpha I with sy being the + + + align:start position:0% +basis vector alpha I with sy being the +number beta I the states I is equal to + + align:start position:0% +number beta I the states I is equal to + + + align:start position:0% +number beta I the states I is equal to +the sum of beta eyes alpha eyes once you + + align:start position:0% +the sum of beta eyes alpha eyes once you + + + align:start position:0% +the sum of beta eyes alpha eyes once you +have the components the vector can be + + align:start position:0% +have the components the vector can be + + + align:start position:0% +have the components the vector can be +reconstructed as the components times + + align:start position:0% +reconstructed as the components times + + + align:start position:0% +reconstructed as the components times +the basis vectors so that's what we did + + align:start position:0% +the basis vectors so that's what we did + + + align:start position:0% +the basis vectors so that's what we did +here we have the components here and + + align:start position:0% +here we have the components here and + + + align:start position:0% +here we have the components here and +therefore the vector is the components + + align:start position:0% +therefore the vector is the components + + + align:start position:0% +therefore the vector is the components +times the basis vectors you can check + + align:start position:0% +times the basis vectors you can check + + + align:start position:0% +times the basis vectors you can check +that if if that makes you a little and + + align:start position:0% +that if if that makes you a little and + + + align:start position:0% +that if if that makes you a little and +you see just put a p 0 here and reach + + align:start position:0% +you see just put a p 0 here and reach + + + align:start position:0% +you see just put a p 0 here and reach +calculate that and you will get that + + align:start position:0% +calculate that and you will get that + + + align:start position:0% +calculate that and you will get that +answer now as written it there it's + + align:start position:0% +answer now as written it there it's + + + align:start position:0% +answer now as written it there it's +really not precise you're making + + align:start position:0% +really not precise you're making + + + align:start position:0% +really not precise you're making +technically a mistake this is equation + + align:start position:0% +technically a mistake this is equation + + + align:start position:0% +technically a mistake this is equation +is technically wrong because that's not + + align:start position:0% +is technically wrong because that's not + + + align:start position:0% +is technically wrong because that's not +n1k that is only the components of n1 k + + align:start position:0% +n1k that is only the components of n1 k + + + align:start position:0% +n1k that is only the components of n1 k +along we had so this will is be hard if + + align:start position:0% +along we had so this will is be hard if + + + align:start position:0% +along we had so this will is be hard if +n1 K has something along the degenerate + + align:start position:0% +n1 K has something along the degenerate + + + align:start position:0% +n1 K has something along the degenerate +subspace we haven't found it but this + + align:start position:0% +subspace we haven't found it but this + + + align:start position:0% +subspace we haven't found it but this +much we found we found part of the + + align:start position:0% +much we found we found part of the + + + align:start position:0% +much we found we found part of the +correction so the generous is always a + + align:start position:0% +correction so the generous is always a + + + align:start position:0% +correction so the generous is always a +complicated thing so we're gonna try to + + align:start position:0% +complicated thing so we're gonna try to + + + align:start position:0% +complicated thing so we're gonna try to +find we're gonna find in fact now the + + align:start position:0% +find we're gonna find in fact now the + + + align:start position:0% +find we're gonna find in fact now the +component of the correction around the + + align:start position:0% +component of the correction around the + + + align:start position:0% +component of the correction around the +degenerate space now in non degenerate + + align:start position:0% +degenerate space now in non degenerate + + + align:start position:0% +degenerate space now in non degenerate +perturbation theory we managed to use + + align:start position:0% +perturbation theory we managed to use + + + align:start position:0% +perturbation theory we managed to use +this equation to calculate fully the + + align:start position:0% +this equation to calculate fully the + + + align:start position:0% +this equation to calculate fully the +state but now we've used this equation + + align:start position:0% +state but now we've used this equation + + + align:start position:0% +state but now we've used this equation +all the way we put states in the + + align:start position:0% +all the way we put states in the + + + align:start position:0% +all the way we put states in the +degenerate subspace and we found the + + align:start position:0% +degenerate subspace and we found the + + + align:start position:0% +degenerate subspace and we found the +energies we put in the other part of the + + align:start position:0% +energies we put in the other part of the + + + align:start position:0% +energies we put in the other part of the +space V hat and we found the part of n1 + + align:start position:0% +space V hat and we found the part of n1 + + + align:start position:0% +space V hat and we found the part of n1 +in in along V hat and we ran out of + + align:start position:0% +in in along V hat and we ran out of + + + align:start position:0% +in in along V hat and we ran out of +things from that order one equation has + + align:start position:0% +things from that order one equation has + + + align:start position:0% +things from that order one equation has +no more information so somehow it must + + align:start position:0% +no more information so somehow it must + + + align:start position:0% +no more information so somehow it must +be that the next equation that we + + align:start position:0% +be that the next equation that we + + + align:start position:0% +be that the next equation that we +usually need to go to second order in + + align:start position:0% +usually need to go to second order in + + + align:start position:0% +usually need to go to second order in +energy will tell us something about the + + align:start position:0% +energy will tell us something about the + + + align:start position:0% +energy will tell us something about the +missing part of n1 so that's the + + align:start position:0% +missing part of n1 so that's the + + + align:start position:0% +missing part of n1 so that's the +surprising thing you have to go to order + + align:start position:0% +surprising thing you have to go to order + + + align:start position:0% +surprising thing you have to go to order +lambda square to find the first order + + align:start position:0% +lambda square to find the first order + + + align:start position:0% +lambda square to find the first order +correction to the degenerate part of the + + align:start position:0% +correction to the degenerate part of the + + + align:start position:0% +correction to the degenerate part of the +state that's why the general + + align:start position:0% +state that's why the general + + + align:start position:0% +state that's why the general +perturbation theory has a is famous for + + align:start position:0% +perturbation theory has a is famous for + + + align:start position:0% +perturbation theory has a is famous for +its complication if you really need to + + align:start position:0% +its complication if you really need to + + + align:start position:0% +its complication if you really need to +go pretty high to find the things so + + align:start position:0% +go pretty high to find the things so + + + align:start position:0% +go pretty high to find the things so +let's do it so this is step three + + align:start position:0% + + + + align:start position:0% + +you hit the order lambda squared + + align:start position:0% +you hit the order lambda squared + + + align:start position:0% +you hit the order lambda squared +equation with M 0 L and therefore the + + align:start position:0% +equation with M 0 L and therefore the + + + align:start position:0% +equation with M 0 L and therefore the +left hand side is going to be 0 because + + align:start position:0% +left hand side is going to be 0 because + + + align:start position:0% +left hand side is going to be 0 because +that operator on the left hand side + + align:start position:0% +that operator on the left hand side + + + align:start position:0% +that operator on the left hand side +always kills those states now you could + + align:start position:0% +always kills those states now you could + + + align:start position:0% +always kills those states now you could +have been a little sloppy here I was + + align:start position:0% +have been a little sloppy here I was + + + align:start position:0% +have been a little sloppy here I was +sloppy when I first solve those + + align:start position:0% +sloppy when I first solve those + + + align:start position:0% +sloppy when I first solve those +equations that I didn't say okay this is + + align:start position:0% +equations that I didn't say okay this is + + + align:start position:0% +equations that I didn't say okay this is +we had I said that's the answer that's + + align:start position:0% +we had I said that's the answer that's + + + align:start position:0% +we had I said that's the answer that's +the whole state + + align:start position:0% +the whole state + + + align:start position:0% +the whole state +there's nothing along the degenerate + + align:start position:0% +there's nothing along the degenerate + + + align:start position:0% +there's nothing along the degenerate +subspace but then if you stop there you + + align:start position:0% +subspace but then if you stop there you + + + align:start position:0% +subspace but then if you stop there you +can live happily the rest of your life + + align:start position:0% +can live happily the rest of your life + + + align:start position:0% +can live happily the rest of your life +but if you go to the next equation you + + align:start position:0% +but if you go to the next equation you + + + align:start position:0% +but if you go to the next equation you +find that it's wrong there was a piece + + align:start position:0% +find that it's wrong there was a piece + + + align:start position:0% +find that it's wrong there was a piece +along the degenerate subspace so let's + + align:start position:0% +along the degenerate subspace so let's + + + align:start position:0% +along the degenerate subspace so let's +see that so we'll also write as we've + + align:start position:0% +see that so we'll also write as we've + + + align:start position:0% +see that so we'll also write as we've +started to do and 1k being equal to n 1k + + align:start position:0% +started to do and 1k being equal to n 1k + + + align:start position:0% +started to do and 1k being equal to n 1k +along V hat plus the piece of n 1k along + + align:start position:0% +along V hat plus the piece of n 1k along + + + align:start position:0% +along V hat plus the piece of n 1k along +the end and this one we got and this one + + align:start position:0% +the end and this one we got and this one + + + align:start position:0% +the end and this one we got and this one +well is it there do we need it does the + + align:start position:0% +well is it there do we need it does the + + + align:start position:0% +well is it there do we need it does the +state receive a correction in that space + + align:start position:0% +state receive a correction in that space + + + align:start position:0% +state receive a correction in that space +or not well let's do the work let's hit + + align:start position:0% +or not well let's do the work let's hit + + + align:start position:0% +or not well let's do the work let's hit +this with those states so what happens + + align:start position:0% +this with those states so what happens + + + align:start position:0% +this with those states so what happens +we have n 0 L e and K 1 minus Delta H + + align:start position:0% +we have n 0 L e and K 1 minus Delta H + + + align:start position:0% +we have n 0 L e and K 1 minus Delta H +and 1k + + align:start position:0% + + + + align:start position:0% + +that's our term there actually I will + + align:start position:0% +that's our term there actually I will + + + align:start position:0% +that's our term there actually I will +write it off twice so I'll copy it again + + align:start position:0% +write it off twice so I'll copy it again + + + align:start position:0% +write it off twice so I'll copy it again +and 0 KL e NK 1 minus Delta H and 1 K + + align:start position:0% +and 0 KL e NK 1 minus Delta H and 1 K + + + align:start position:0% +and 0 KL e NK 1 minus Delta H and 1 K +why do I copied again because I will + + align:start position:0% +why do I copied again because I will + + + align:start position:0% +why do I copied again because I will +just put here on V hat and on V n so it + + align:start position:0% +just put here on V hat and on V n so it + + + align:start position:0% +just put here on V hat and on V n so it +was one term with an N 1 K but you know + + align:start position:0% +was one term with an N 1 K but you know + + + align:start position:0% +was one term with an N 1 K but you know +the N 1 K vector has components along + + align:start position:0% +the N 1 K vector has components along + + + align:start position:0% +the N 1 K vector has components along +two subspaces and therefore we might as + + align:start position:0% +two subspaces and therefore we might as + + + align:start position:0% +two subspaces and therefore we might as +well put each one separately so we can + + align:start position:0% +well put each one separately so we can + + + align:start position:0% +well put each one separately so we can +think about them in a clearer way then + + align:start position:0% +think about them in a clearer way then + + + align:start position:0% +think about them in a clearer way then +what else there's one more term the e n + + align:start position:0% +what else there's one more term the e n + + + align:start position:0% +what else there's one more term the e n +2 K and that is relatively simple + + align:start position:0% +2 K and that is relatively simple + + + align:start position:0% +2 K and that is relatively simple +because that's e and k 2 and then we + + align:start position:0% +because that's e and k 2 and then we + + + align:start position:0% +because that's e and k 2 and then we +have the overlap of at n 0 L with an N 0 + + align:start position:0% +have the overlap of at n 0 L with an N 0 + + + align:start position:0% +have the overlap of at n 0 L with an N 0 +K which is a Delta L K so this whole + + align:start position:0% +K which is a Delta L K so this whole + + + align:start position:0% +K which is a Delta L K so this whole +thing must be 0 that was the right hand + + align:start position:0% +thing must be 0 that was the right hand + + + align:start position:0% +thing must be 0 that was the right hand +side of the equation but the left hand + + align:start position:0% +side of the equation but the left hand + + + align:start position:0% +side of the equation but the left hand +side of the equation was 0 so that's 0 + + align:start position:0% +side of the equation was 0 so that's 0 + + + align:start position:0% +side of the equation was 0 so that's 0 +ok so now we have to think about this + + align:start position:0% +ok so now we have to think about this + + + align:start position:0% +ok so now we have to think about this +this terms what do we know what is 0 to + + align:start position:0% +this terms what do we know what is 0 to + + + align:start position:0% +this terms what do we know what is 0 to +begin with what is not 0 this term in + + align:start position:0% +begin with what is not 0 this term in + + + align:start position:0% +begin with what is not 0 this term in +here we know in 1 K already we found it + + align:start position:0% +here we know in 1 K already we found it + + + align:start position:0% +here we know in 1 K already we found it +there so that's nice we know n 1 K we + + align:start position:0% +there so that's nice we know n 1 K we + + + align:start position:0% +there so that's nice we know n 1 K we +know these Corrections but this is + + align:start position:0% +know these Corrections but this is + + + align:start position:0% +know these Corrections but this is +simpler because n 0 L is in the + + align:start position:0% +simpler because n 0 L is in the + + + align:start position:0% +simpler because n 0 L is in the +degenerate subspace this is a number and + + align:start position:0% +degenerate subspace this is a number and + + + align:start position:0% +degenerate subspace this is a number and +this is in big hat so that's 0 again + + align:start position:0% + + + + align:start position:0% + +okay so that's a simplification here we + + align:start position:0% +okay so that's a simplification here we + + + align:start position:0% +okay so that's a simplification here we +have a very interesting situation I will + + align:start position:0% +have a very interesting situation I will + + + align:start position:0% +have a very interesting situation I will +have the Delta H and we have this basis + + align:start position:0% +have the Delta H and we have this basis + + + align:start position:0% +have the Delta H and we have this basis +state of the degenerate subspace we know + + align:start position:0% +state of the degenerate subspace we know + + + align:start position:0% +state of the degenerate subspace we know +that Delta H is diagonal in the + + align:start position:0% +that Delta H is diagonal in the + + + align:start position:0% +that Delta H is diagonal in the +degenerate subspace but is this n0l an + + align:start position:0% +degenerate subspace but is this n0l an + + + align:start position:0% +degenerate subspace but is this n0l an +eigenvalue of Delta H not quite because + + align:start position:0% +eigenvalue of Delta H not quite because + + + align:start position:0% +eigenvalue of Delta H not quite because +being diagonal these basis vectors are + + align:start position:0% +being diagonal these basis vectors are + + + align:start position:0% +being diagonal these basis vectors are +provide make Delta H diagonal so Delta H + + align:start position:0% +provide make Delta H diagonal so Delta H + + + align:start position:0% +provide make Delta H diagonal so Delta H +is diagonal in this subspace but doesn't + + align:start position:0% +is diagonal in this subspace but doesn't + + + align:start position:0% +is diagonal in this subspace but doesn't +mean this thing is an eigenvector + + align:start position:0% +mean this thing is an eigenvector + + + align:start position:0% +mean this thing is an eigenvector +because it can give you something + + align:start position:0% +because it can give you something + + + align:start position:0% +because it can give you something +outside the degenerate subspace so we + + align:start position:0% +outside the degenerate subspace so we + + + align:start position:0% +outside the degenerate subspace so we +cannot quite just say that this the + + align:start position:0% +cannot quite just say that this the + + + align:start position:0% +cannot quite just say that this the +eigenvalue of this is the first energy + + align:start position:0% +eigenvalue of this is the first energy + + + align:start position:0% +eigenvalue of this is the first energy +correction but actually we can let me + + align:start position:0% +correction but actually we can let me + + + align:start position:0% +correction but actually we can let me +explain that so let's look at this term + + align:start position:0% +explain that so let's look at this term + + + align:start position:0% +explain that so let's look at this term +alone with this term alone now this time + + align:start position:0% +alone with this term alone now this time + + + align:start position:0% +alone with this term alone now this time +I cannot kill this this constant because + + align:start position:0% +I cannot kill this this constant because + + + align:start position:0% +I cannot kill this this constant because +this is in the degenerate subspace and + + align:start position:0% +this is in the degenerate subspace and + + + align:start position:0% +this is in the degenerate subspace and +this is in the degenerate subspace so we + + align:start position:0% +this is in the degenerate subspace so we + + + align:start position:0% +this is in the degenerate subspace so we +will have to deal with that so let's + + align:start position:0% +will have to deal with that so let's + + + align:start position:0% +will have to deal with that so let's +let's do this okay so I'll put here M 0 + + align:start position:0% +let's do this okay so I'll put here M 0 + + + align:start position:0% +let's do this okay so I'll put here M 0 +L Delta H and 1k we're going to try to + + align:start position:0% +L Delta H and 1k we're going to try to + + + align:start position:0% +L Delta H and 1k we're going to try to +simplify this and the way to do it this + + align:start position:0% +simplify this and the way to do it this + + + align:start position:0% +simplify this and the way to do it this +is n 1k very important in VN is to + + align:start position:0% +is n 1k very important in VN is to + + + align:start position:0% +is n 1k very important in VN is to +insert a resolution of the identity here + + align:start position:0% +insert a resolution of the identity here + + + align:start position:0% +insert a resolution of the identity here +so + + align:start position:0% +so + + + align:start position:0% +so +I'll do it we'll put n0 L Delta H and + + align:start position:0% +I'll do it we'll put n0 L Delta H and + + + align:start position:0% +I'll do it we'll put n0 L Delta H and +now we'll put the whole resolution of + + align:start position:0% +now we'll put the whole resolution of + + + align:start position:0% +now we'll put the whole resolution of +the identity so we'll put the sum over Q + + align:start position:0% +the identity so we'll put the sum over Q + + + align:start position:0% +the identity so we'll put the sum over Q +and 0 Q and 0 Q plus a sum over P p 0 p + + align:start position:0% +and 0 Q and 0 Q plus a sum over P p 0 p + + + align:start position:0% +and 0 Q and 0 Q plus a sum over P p 0 p +0 all acting on em 1k of VN I actually + + align:start position:0% +0 all acting on em 1k of VN I actually + + + align:start position:0% +0 all acting on em 1k of VN I actually +want to remark that all what I'm doing + + align:start position:0% +want to remark that all what I'm doing + + + align:start position:0% +want to remark that all what I'm doing +in this line so let's break this this + + align:start position:0% +in this line so let's break this this + + + align:start position:0% +in this line so let's break this this +the equation was up to here and we + + align:start position:0% +the equation was up to here and we + + + align:start position:0% +the equation was up to here and we +decided to try to understand this term + + align:start position:0% +decided to try to understand this term + + + align:start position:0% +decided to try to understand this term +so we're trying to understand this term + + align:start position:0% +so we're trying to understand this term + + + align:start position:0% +so we're trying to understand this term +just that term now Delta H here is + + align:start position:0% +just that term now Delta H here is + + + align:start position:0% +just that term now Delta H here is +acting between and the generates + + align:start position:0% +acting between and the generates + + + align:start position:0% +acting between and the generates +eigenstate here and here some arbitrary + + align:start position:0% +eigenstate here and here some arbitrary + + + align:start position:0% +eigenstate here and here some arbitrary +state in the degenerate subspace so we + + align:start position:0% +state in the degenerate subspace so we + + + align:start position:0% +state in the degenerate subspace so we +go here and we say ok since this is in + + align:start position:0% +go here and we say ok since this is in + + + align:start position:0% +go here and we say ok since this is in +the degenerate subspace that's inner + + align:start position:0% +the degenerate subspace that's inner + + + align:start position:0% +the degenerate subspace that's inner +product with vector in v hat with this + + align:start position:0% +product with vector in v hat with this + + + align:start position:0% +product with vector in v hat with this +is 0 so that part of the resolution of + + align:start position:0% +is 0 so that part of the resolution of + + + align:start position:0% +is 0 so that part of the resolution of +the identity is not relevant + + align:start position:0% +the identity is not relevant + + + align:start position:0% +the identity is not relevant +[Applause] + + align:start position:0% + + + + align:start position:0% + +if that part of the resolution of the + + align:start position:0% +if that part of the resolution of the + + + align:start position:0% +if that part of the resolution of the +identity is not relevant we are left + + align:start position:0% +identity is not relevant we are left + + + align:start position:0% +identity is not relevant we are left +with and sum over Q and zero L Delta H + + align:start position:0% +with and sum over Q and zero L Delta H + + + align:start position:0% +with and sum over Q and zero L Delta H +and 0 q n0 q times n 1 k vm and now you + + align:start position:0% +and 0 q n0 q times n 1 k vm and now you + + + align:start position:0% +and 0 q n0 q times n 1 k vm and now you +can use that this matrix is indeed + + align:start position:0% +can use that this matrix is indeed + + + align:start position:0% +can use that this matrix is indeed +diagonal in the degenerate subspace and + + align:start position:0% +diagonal in the degenerate subspace and + + + align:start position:0% +diagonal in the degenerate subspace and +therefore this matrix element is the + + align:start position:0% +therefore this matrix element is the + + + align:start position:0% +therefore this matrix element is the +energy E and L 1 the first order + + align:start position:0% +energy E and L 1 the first order + + + align:start position:0% +energy E and L 1 the first order +correction times a delta L Q and then we + + align:start position:0% +correction times a delta L Q and then we + + + align:start position:0% +correction times a delta L Q and then we +can do the sum over Q because there is a + + align:start position:0% +can do the sum over Q because there is a + + + align:start position:0% +can do the sum over Q because there is a +delta function here and this becomes e + + align:start position:0% +delta function here and this becomes e + + + align:start position:0% +delta function here and this becomes e +and L 1 and 0 L and 1 k VN so this is + + align:start position:0% +and L 1 and 0 L and 1 k VN so this is + + + align:start position:0% +and L 1 and 0 L and 1 k VN so this is +very nice it took us a little bit of + + align:start position:0% +very nice it took us a little bit of + + + align:start position:0% +very nice it took us a little bit of +work but look what has happened this + + align:start position:0% +work but look what has happened this + + + align:start position:0% +work but look what has happened this +Delta H term is going to become the same + + align:start position:0% +Delta H term is going to become the same + + + align:start position:0% +Delta H term is going to become the same +structure and 0 L and 1k overlap so it's + + align:start position:0% +structure and 0 L and 1k overlap so it's + + + align:start position:0% +structure and 0 L and 1k overlap so it's +great progress so what does our equation + + align:start position:0% +great progress so what does our equation + + + align:start position:0% +great progress so what does our equation +become well the from the first term this + + align:start position:0% +become well the from the first term this + + + align:start position:0% +become well the from the first term this +is the rest of the end of the aside from + + align:start position:0% +is the rest of the end of the aside from + + + align:start position:0% +is the rest of the end of the aside from +the first term we have minus and 0 + + align:start position:0% + + + + align:start position:0% + +Delta H and 1k envy hat that's all that + + align:start position:0% +Delta H and 1k envy hat that's all that + + + align:start position:0% +Delta H and 1k envy hat that's all that +was left from that first term and this + + align:start position:0% +was left from that first term and this + + + align:start position:0% +was left from that first term and this +term is known because N 1 is known along + + align:start position:0% +term is known because N 1 is known along + + + align:start position:0% +term is known because N 1 is known along +the rest of the hilbert space the second + + align:start position:0% +the rest of the hilbert space the second + + + align:start position:0% +the rest of the hilbert space the second +term over there that was giving us + + align:start position:0% +term over there that was giving us + + + align:start position:0% +term over there that was giving us +trouble has become something very simple + + align:start position:0% +trouble has become something very simple + + + align:start position:0% +trouble has become something very simple +it has become e NK minus e n L both 1 + + align:start position:0% + + + + align:start position:0% + +multiplied by n 0 L + 1 K I could put + + align:start position:0% +multiplied by n 0 L + 1 K I could put + + + align:start position:0% +multiplied by n 0 L + 1 K I could put +this VM or now I may not put it either + + align:start position:0% +this VM or now I may not put it either + + + align:start position:0% +this VM or now I may not put it either +because I'm already projecting to a + + align:start position:0% +because I'm already projecting to a + + + align:start position:0% +because I'm already projecting to a +state in the degenerate subspace so I'm + + align:start position:0% +state in the degenerate subspace so I'm + + + align:start position:0% +state in the degenerate subspace so I'm +finding the component along the + + align:start position:0% +finding the component along the + + + align:start position:0% +finding the component along the +degenerate subspace so even if n1 k had + + align:start position:0% +degenerate subspace so even if n1 k had + + + align:start position:0% +degenerate subspace so even if n1 k had +a piece along we had it would drop out + + align:start position:0% +a piece along we had it would drop out + + + align:start position:0% +a piece along we had it would drop out +here so it's completely legal and it's + + align:start position:0% +here so it's completely legal and it's + + + align:start position:0% +here so it's completely legal and it's +simpler to erase the VN k and then the + + align:start position:0% +simpler to erase the VN k and then the + + + align:start position:0% +simpler to erase the VN k and then the +last term is still there + e + k2 Delta + + align:start position:0% +last term is still there + e + k2 Delta + + + align:start position:0% +last term is still there + e + k2 Delta +L K equals 0 ok this is our master + + align:start position:0% +L K equals 0 ok this is our master + + + align:start position:0% +L K equals 0 ok this is our master +equation after thinking of this equation + + align:start position:0% +equation after thinking of this equation + + + align:start position:0% +equation after thinking of this equation +for a while and using our properties we + + align:start position:0% +for a while and using our properties we + + + align:start position:0% +for a while and using our properties we +got this far it's a very nice equation + + align:start position:0% +got this far it's a very nice equation + + + align:start position:0% +got this far it's a very nice equation +it does give you the second-order + + align:start position:0% +it does give you the second-order + + + align:start position:0% +it does give you the second-order +energies we were looking for the part of + + align:start position:0% +energies we were looking for the part of + + + align:start position:0% +energies we were looking for the part of +the state along the degenerate subspace + + align:start position:0% +the state along the degenerate subspace + + + align:start position:0% +the state along the degenerate subspace +this was our main unknown and but still + + align:start position:0% +this was our main unknown and but still + + + align:start position:0% +this was our main unknown and but still +we can get the energies why because we + + align:start position:0% +we can get the energies why because we + + + align:start position:0% +we can get the energies why because we +can + + align:start position:0% +can + + + align:start position:0% +can +take L equals 2k in which case the term + + align:start position:0% +take L equals 2k in which case the term + + + align:start position:0% +take L equals 2k in which case the term +that we know now drops out because n L + + align:start position:0% +that we know now drops out because n L + + + align:start position:0% +that we know now drops out because n L +equals 2k this thing's cancelled so when + + align:start position:0% +equals 2k this thing's cancelled so when + + + align:start position:0% +equals 2k this thing's cancelled so when +L is equal to K we get that e MK to the + + align:start position:0% +L is equal to K we get that e MK to the + + + align:start position:0% +L is equal to K we get that e MK to the +second order correction to the energy is + + align:start position:0% +second order correction to the energy is + + + align:start position:0% +second order correction to the energy is +M 0 K Delta H and 1 K V hat that's it + + align:start position:0% +M 0 K Delta H and 1 K V hat that's it + + + align:start position:0% +M 0 K Delta H and 1 K V hat that's it +that's your second correction to the + + align:start position:0% +that's your second correction to the + + + align:start position:0% +that's your second correction to the +energy and that's very nice + + align:start position:0% + + + + align:start position:0% + +why do we say that's it because we + + align:start position:0% +why do we say that's it because we + + + align:start position:0% +why do we say that's it because we +actually have the answer for N 1 so we + + align:start position:0% +actually have the answer for N 1 so we + + + align:start position:0% +actually have the answer for N 1 so we +can find a complete formula for this + + align:start position:0% +can find a complete formula for this + + + align:start position:0% +can find a complete formula for this +I'll write it here after a couple of + + align:start position:0% +I'll write it here after a couple of + + + align:start position:0% +I'll write it here after a couple of +steps of algebra this gives minus the + + align:start position:0% +steps of algebra this gives minus the + + + align:start position:0% +steps of algebra this gives minus the +sum over P Delta H MK p over p 0 minus e + + align:start position:0% +sum over P Delta H MK p over p 0 minus e + + + align:start position:0% +sum over P Delta H MK p over p 0 minus e +m 0 squared look at that formula it has + + align:start position:0% +m 0 squared look at that formula it has + + + align:start position:0% +m 0 squared look at that formula it has +the same form as the second order + + align:start position:0% +the same form as the second order + + + align:start position:0% +the same form as the second order +correction to non degenerate states same + + align:start position:0% +correction to non degenerate states same + + + align:start position:0% +correction to non degenerate states same +look except that you only sum over the + + align:start position:0% +look except that you only sum over the + + + align:start position:0% +look except that you only sum over the +states that are outside the degenerate + + align:start position:0% +states that are outside the degenerate + + + align:start position:0% +states that are outside the degenerate +space + + align:start position:0% +space + + + align:start position:0% +space +it was exactly of this form the second + + align:start position:0% +it was exactly of this form the second + + + align:start position:0% +it was exactly of this form the second +order energy correction so it's kind of + + align:start position:0% +order energy correction so it's kind of + + + align:start position:0% +order energy correction so it's kind of +nice and simple but let's look at this + + align:start position:0% +nice and simple but let's look at this + + + align:start position:0% +nice and simple but let's look at this +equation again and here is a the thing + + align:start position:0% +equation again and here is a the thing + + + align:start position:0% +equation again and here is a the thing +that would have been shocking if we + + align:start position:0% +that would have been shocking if we + + + align:start position:0% +that would have been shocking if we +didn't do this right if we had set L + + align:start position:0% +didn't do this right if we had set L + + + align:start position:0% +didn't do this right if we had set L +different from K here if L is different + + align:start position:0% +different from K here if L is different + + + align:start position:0% +different from K here if L is different +from K then this term is zero if we + + align:start position:0% +from K then this term is zero if we + + + align:start position:0% +from K then this term is zero if we +didn't think if we hadn't suspected that + + align:start position:0% +didn't think if we hadn't suspected that + + + align:start position:0% +didn't think if we hadn't suspected that +the state n1 k had a piece along the + + align:start position:0% +the state n1 k had a piece along the + + + align:start position:0% +the state n1 k had a piece along the +degenerate subspace we would have not + + align:start position:0% +degenerate subspace we would have not + + + align:start position:0% +degenerate subspace we would have not +introduced it and we would have had not + + align:start position:0% +introduced it and we would have had not + + + align:start position:0% +introduced it and we would have had not +this term and the equation would have + + align:start position:0% +this term and the equation would have + + + align:start position:0% +this term and the equation would have +become this equal to zero which is not + + align:start position:0% +become this equal to zero which is not + + + align:start position:0% +become this equal to zero which is not +you have there n1 of K and you can look + + align:start position:0% +you have there n1 of K and you can look + + + align:start position:0% +you have there n1 of K and you can look +at it and look at it for hours and it's + + align:start position:0% +at it and look at it for hours and it's + + + align:start position:0% +at it and look at it for hours and it's +just not zero so unless we have this + + align:start position:0% +just not zero so unless we have this + + + align:start position:0% +just not zero so unless we have this +piece the equation doesn't make sense so + + align:start position:0% +piece the equation doesn't make sense so + + + align:start position:0% +piece the equation doesn't make sense so +this proves that the state must develop + + align:start position:0% +this proves that the state must develop + + + align:start position:0% +this proves that the state must develop +a component along the degenerate + + align:start position:0% +a component along the degenerate + + + align:start position:0% +a component along the degenerate +subspace and let's now finally get it + + align:start position:0% +subspace and let's now finally get it + + + align:start position:0% +subspace and let's now finally get it +it's just one line at this point we + + align:start position:0% +it's just one line at this point we + + + align:start position:0% +it's just one line at this point we +don't have to do much + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +so when L is different from K L + + align:start position:0% +so when L is different from K L + + + align:start position:0% +so when L is different from K L +different from K so what do we get for + + align:start position:0% +different from K so what do we get for + + + align:start position:0% +different from K so what do we get for +the equation look at it there we can + + align:start position:0% +the equation look at it there we can + + + align:start position:0% +the equation look at it there we can +solve directly for the piece and 0 L and + + align:start position:0% +solve directly for the piece and 0 L and + + + align:start position:0% +solve directly for the piece and 0 L and +1 K is equal to solve for the second + + align:start position:0% +1 K is equal to solve for the second + + + align:start position:0% +1 K is equal to solve for the second +term this other term goes on the + + align:start position:0% +term this other term goes on the + + + align:start position:0% +term this other term goes on the +right-hand side so and 0 L Delta H and 1 + + align:start position:0% +right-hand side so and 0 L Delta H and 1 + + + align:start position:0% +right-hand side so and 0 L Delta H and 1 +K over E and K 1 minus e and L 1 and + + align:start position:0% +K over E and K 1 minus e and L 1 and + + + align:start position:0% +K over E and K 1 minus e and L 1 and +here is another thing that ended up + + align:start position:0% +here is another thing that ended up + + + align:start position:0% +here is another thing that ended up +working well if the degeneracy had not + + align:start position:0% +working well if the degeneracy had not + + + align:start position:0% +working well if the degeneracy had not +been broken we're doing L different from + + align:start position:0% +been broken we're doing L different from + + + align:start position:0% +been broken we're doing L different from +K if some of these would have been 0 + + align:start position:0% +K if some of these would have been 0 + + + align:start position:0% +K if some of these would have been 0 +this would give you 0 in the denominator + + align:start position:0% +this would give you 0 in the denominator + + + align:start position:0% +this would give you 0 in the denominator +this wouldn't work out so it was urgent + + align:start position:0% +this wouldn't work out so it was urgent + + + align:start position:0% +this wouldn't work out so it was urgent +here that all the degeneracy had been + + align:start position:0% +here that all the degeneracy had been + + + align:start position:0% +here that all the degeneracy had been +broken the first order otherwise you + + align:start position:0% +broken the first order otherwise you + + + align:start position:0% +broken the first order otherwise you +couldn't have computed this state this + + align:start position:0% +couldn't have computed this state this + + + align:start position:0% +couldn't have computed this state this +way + + align:start position:0% + + + + align:start position:0% + +this means that n 1k to wrap it up here + + align:start position:0% +this means that n 1k to wrap it up here + + + align:start position:0% +this means that n 1k to wrap it up here +is when this in the subspace V n is the + + align:start position:0% +is when this in the subspace V n is the + + + align:start position:0% +is when this in the subspace V n is the +sum over L different from K because this + + align:start position:0% +sum over L different from K because this + + + align:start position:0% +sum over L different from K because this +inner product only makes sense for L + + align:start position:0% +inner product only makes sense for L + + + align:start position:0% +inner product only makes sense for L +different from K of n 0 L times this + + align:start position:0% +different from K of n 0 L times this + + + align:start position:0% +different from K of n 0 L times this +coefficient 1 over e MK 1 minus e and L + + align:start position:0% +coefficient 1 over e MK 1 minus e and L + + + align:start position:0% +coefficient 1 over e MK 1 minus e and L + + align:start position:0% + + + align:start position:0% +and 0l delta h and 1k it's a lot of work + + align:start position:0% +and 0l delta h and 1k it's a lot of work + + + align:start position:0% +and 0l delta h and 1k it's a lot of work +to get here but actually it's good that + + align:start position:0% +to get here but actually it's good that + + + align:start position:0% +to get here but actually it's good that +we could get there if you even want to + + align:start position:0% +we could get there if you even want to + + + align:start position:0% +we could get there if you even want to +write it more explicitly you substitute + + align:start position:0% +write it more explicitly you substitute + + + align:start position:0% +write it more explicitly you substitute +what n1 k is and it goes there + + align:start position:0% +what n1 k is and it goes there + + + align:start position:0% +what n1 k is and it goes there +now there's something a little strange + + align:start position:0% +now there's something a little strange + + + align:start position:0% +now there's something a little strange +at first sight if you look at it you say + + align:start position:0% +at first sight if you look at it you say + + + align:start position:0% +at first sight if you look at it you say +okay let's see this is first-order in + + align:start position:0% +okay let's see this is first-order in + + + align:start position:0% +okay let's see this is first-order in +perturbation theory we have to go to the + + align:start position:0% +perturbation theory we have to go to the + + + align:start position:0% +perturbation theory we have to go to the +second order equation and that's why we + + align:start position:0% +second order equation and that's why we + + + align:start position:0% +second order equation and that's why we +seem to be counting orders wrong because + + align:start position:0% +seem to be counting orders wrong because + + + align:start position:0% +seem to be counting orders wrong because +this is first order in perturbation this + + align:start position:0% +this is first order in perturbation this + + + align:start position:0% +this is first order in perturbation this +is another order in perturbation that's + + align:start position:0% +is another order in perturbation that's + + + align:start position:0% +is another order in perturbation that's +second order in perturbation that's + + align:start position:0% +second order in perturbation that's + + + align:start position:0% +second order in perturbation that's +indeed Delta H and one is second order + + align:start position:0% +indeed Delta H and one is second order + + + align:start position:0% +indeed Delta H and one is second order +Delta H and one appeared to second order + + align:start position:0% +Delta H and one appeared to second order + + + align:start position:0% +Delta H and one appeared to second order +so how come we'll get a first order term + + align:start position:0% +so how come we'll get a first order term + + + align:start position:0% +so how come we'll get a first order term +that seems to depend on second order + + align:start position:0% +that seems to depend on second order + + + align:start position:0% +that seems to depend on second order +stuff maybe it's wrong what we did and + + align:start position:0% +stuff maybe it's wrong what we did and + + + align:start position:0% +stuff maybe it's wrong what we did and +we we thought we were gonna get the + + align:start position:0% +we we thought we were gonna get the + + + align:start position:0% +we we thought we were gonna get the +degenerate first order piece from the + + align:start position:0% +degenerate first order piece from the + + + align:start position:0% +degenerate first order piece from the +second equation but here this is hitting + + align:start position:0% +second equation but here this is hitting + + + align:start position:0% +second equation but here this is hitting +us back yes + + align:start position:0% +us back yes + + + align:start position:0% +us back yes +the denominator is also first-order so + + align:start position:0% +the denominator is also first-order so + + + align:start position:0% +the denominator is also first-order so +this is second order this is first order + + align:start position:0% +this is second order this is first order + + + align:start position:0% +this is second order this is first order +the ratio is first order all is good + + align:start position:0% +the ratio is first order all is good + + + align:start position:0% +the ratio is first order all is good +here this is a good formula this is a + + align:start position:0% +here this is a good formula this is a + + + align:start position:0% +here this is a good formula this is a +real result so this completes our + + align:start position:0% +real result so this completes our + + + align:start position:0% +real result so this completes our +analysis of the general perturbation + + align:start position:0% +analysis of the general perturbation + + + align:start position:0% +analysis of the general perturbation +theory when the perturbation the first + + align:start position:0% +theory when the perturbation the first + + + align:start position:0% +theory when the perturbation the first +order perturbation splits all the levels + + align:start position:0% +order perturbation splits all the levels + + + align:start position:0% +order perturbation splits all the levels +what we're going to do now is set the + + align:start position:0% +what we're going to do now is set the + + + align:start position:0% +what we're going to do now is set the +general perturbation theory when the + + align:start position:0% +general perturbation theory when the + + + align:start position:0% +general perturbation theory when the +first order correction doesn't split any + + align:start position:0% +first order correction doesn't split any + + + align:start position:0% +first order correction doesn't split any +of the levels doesn't split them at all + + align:start position:0% +of the levels doesn't split them at all + + + align:start position:0% +of the levels doesn't split them at all +what happens what can we do \ No newline at end of file diff --git a/EBdgFFf54U0.txt b/EBdgFFf54U0.txt new file mode 100644 index 0000000000000000000000000000000000000000..940c73a627313ca7d0b57711135afd8a2411852e --- /dev/null +++ b/EBdgFFf54U0.txt @@ -0,0 +1,12680 @@ +align:start position:0% + +foreign + + align:start position:0% + + + + align:start position:0% + +okay so uh last time + + align:start position:0% + + + + align:start position:0% + +we introduced pre-hilbert spaces + + align:start position:0% + + + + align:start position:0% + +as Specter spaces uh that come equipped + + align:start position:0% +as Specter spaces uh that come equipped + + + align:start position:0% +as Specter spaces uh that come equipped +with a hermitian inner product our + + align:start position:0% +with a hermitian inner product our + + + align:start position:0% +with a hermitian inner product our +mission inner product is linear is uh so + + align:start position:0% +mission inner product is linear is uh so + + + align:start position:0% +mission inner product is linear is uh so +it's a pairing between two elements that + + align:start position:0% +it's a pairing between two elements that + + + align:start position:0% +it's a pairing between two elements that +gives you a complex number that's linear + + align:start position:0% +gives you a complex number that's linear + + + align:start position:0% +gives you a complex number that's linear +in the first entry + + align:start position:0% +in the first entry + + + align:start position:0% +in the first entry +um + + align:start position:0% +um + + + align:start position:0% +um +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +and if you switch the entries that's + + align:start position:0% +and if you switch the entries that's + + + align:start position:0% +and if you switch the entries that's +equal to the pairing of the original two + + align:start position:0% +equal to the pairing of the original two + + + align:start position:0% +equal to the pairing of the original two +entries uh + + align:start position:0% +entries uh + + + align:start position:0% +entries uh +taking the complex conjugate of that and + + align:start position:0% +taking the complex conjugate of that and + + + align:start position:0% +taking the complex conjugate of that and +it's positive definite meaning if I take + + align:start position:0% +it's positive definite meaning if I take + + + align:start position:0% +it's positive definite meaning if I take +the inner product of a vector with + + align:start position:0% +the inner product of a vector with + + + align:start position:0% +the inner product of a vector with +itself it's not negative and zero if and + + align:start position:0% +itself it's not negative and zero if and + + + align:start position:0% +itself it's not negative and zero if and +only if + + align:start position:0% +only if + + + align:start position:0% +only if +um + + align:start position:0% +um + + + align:start position:0% +um +the element is zero and we proved the + + align:start position:0% +the element is zero and we proved the + + + align:start position:0% +the element is zero and we proved the +koshy Schwartz inequality so let me + + align:start position:0% +koshy Schwartz inequality so let me + + + align:start position:0% +koshy Schwartz inequality so let me +actually just recall that we defined + + align:start position:0% + + + + align:start position:0% + +for if H is a + + align:start position:0% + + + + align:start position:0% + +pre-hubert space + + align:start position:0% +pre-hubert space + + + align:start position:0% +pre-hubert space +we defined + + align:start position:0% +we defined + + + align:start position:0% +we defined +what we called uh or using this Norm + + align:start position:0% +what we called uh or using this Norm + + + align:start position:0% +what we called uh or using this Norm +notation although I haven't proved it to + + align:start position:0% +notation although I haven't proved it to + + + align:start position:0% +notation although I haven't proved it to +Norm yet + + align:start position:0% +Norm yet + + + align:start position:0% +Norm yet +to be the inner product of V with itself + + align:start position:0% +to be the inner product of V with itself + + + align:start position:0% +to be the inner product of V with itself +um + + align:start position:0% + + + + align:start position:0% + +raised to the one-half power + + align:start position:0% +raised to the one-half power + + + align:start position:0% +raised to the one-half power +and this is a non-negative real number + + align:start position:0% +and this is a non-negative real number + + + align:start position:0% +and this is a non-negative real number +uh + + align:start position:0% +uh + + + align:start position:0% +uh +this is a non-negative number so + + align:start position:0% +this is a non-negative number so + + + align:start position:0% +this is a non-negative number so +taking the one-half power is Meaningful + + align:start position:0% +taking the one-half power is Meaningful + + + align:start position:0% +taking the one-half power is Meaningful +um + + align:start position:0% +um + + + align:start position:0% +um +and we proved at the end of last time + + align:start position:0% +and we proved at the end of last time + + + align:start position:0% +and we proved at the end of last time +the koshy Schwartz inequality + + align:start position:0% +the koshy Schwartz inequality + + + align:start position:0% +the koshy Schwartz inequality +that uh + + align:start position:0% +that uh + + + align:start position:0% +that uh +for all you + + align:start position:0% +for all you + + + align:start position:0% +for all you +and B and H + + align:start position:0% +and B and H + + + align:start position:0% +and B and H +if + + align:start position:0% +if + + + align:start position:0% +if +I take the inner product of u and v take + + align:start position:0% +I take the inner product of u and v take + + + align:start position:0% +I take the inner product of u and v take +its absolute value this is less than or + + align:start position:0% +its absolute value this is less than or + + + align:start position:0% +its absolute value this is less than or +equal to + + align:start position:0% +equal to + + + align:start position:0% +equal to +normal View + + align:start position:0% + + + + align:start position:0% + +times the norm of V + + align:start position:0% +times the norm of V + + + align:start position:0% +times the norm of V +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so now let's uh use this to actually + + align:start position:0% +so now let's uh use this to actually + + + align:start position:0% +so now let's uh use this to actually +prove or to prove that this thing that + + align:start position:0% +prove or to prove that this thing that + + + align:start position:0% +prove or to prove that this thing that +I've been + + align:start position:0% +I've been + + + align:start position:0% +I've been +uh + + align:start position:0% +uh + + + align:start position:0% +uh +denoting what this Norm notation is in + + align:start position:0% +denoting what this Norm notation is in + + + align:start position:0% +denoting what this Norm notation is in +fact a norm on a pre-hilbert space + + align:start position:0% + + + + align:start position:0% + +so theorem + + align:start position:0% +so theorem + + + align:start position:0% +so theorem +with h + + align:start position:0% +with h + + + align:start position:0% +with h +is a + + align:start position:0% + + + + align:start position:0% + +the Hilbert space + + align:start position:0% + + + + align:start position:0% + +then + + align:start position:0% + + + + align:start position:0% + +this uh thing here defined in this way + + align:start position:0% +this uh thing here defined in this way + + + align:start position:0% +this uh thing here defined in this way +is + + align:start position:0% + + + + align:start position:0% + +a norm on H okay + + align:start position:0% + + + + align:start position:0% + +so remember we have to prove to or we + + align:start position:0% +so remember we have to prove to or we + + + align:start position:0% +so remember we have to prove to or we +have to prove three things for for + + align:start position:0% +have to prove three things for for + + + align:start position:0% +have to prove three things for for +something to be a norm we have to prove + + align:start position:0% +something to be a norm we have to prove + + + align:start position:0% +something to be a norm we have to prove +it's positive definite and then we also + + align:start position:0% +it's positive definite and then we also + + + align:start position:0% +it's positive definite and then we also +have to prove homogeneity and the + + align:start position:0% +have to prove homogeneity and the + + + align:start position:0% +have to prove homogeneity and the +triangle inequality so + + align:start position:0% +triangle inequality so + + + align:start position:0% +triangle inequality so +um + + align:start position:0% + + + + align:start position:0% + +note that + + align:start position:0% + + + + align:start position:0% + +this quantity here equals zero + + align:start position:0% +this quantity here equals zero + + + align:start position:0% +this quantity here equals zero +if and only if + + align:start position:0% +if and only if + + + align:start position:0% +if and only if +the inner product of V with itself is + + align:start position:0% +the inner product of V with itself is + + + align:start position:0% +the inner product of V with itself is +zero which + + align:start position:0% +zero which + + + align:start position:0% +zero which +by the positive definite quantity of a + + align:start position:0% +by the positive definite quantity of a + + + align:start position:0% +by the positive definite quantity of a +hermitian inner product implies that V + + align:start position:0% +hermitian inner product implies that V + + + align:start position:0% +hermitian inner product implies that V +equals zero so that proves that this + + align:start position:0% +equals zero so that proves that this + + + align:start position:0% +equals zero so that proves that this +function here on H is in fact positive + + align:start position:0% +function here on H is in fact positive + + + align:start position:0% +function here on H is in fact positive +definite + + align:start position:0% +definite + + + align:start position:0% +definite +um + + align:start position:0% +um + + + align:start position:0% +um +now if Lambda is a complex number + + align:start position:0% +now if Lambda is a complex number + + + align:start position:0% +now if Lambda is a complex number +V is in h if I take + + align:start position:0% + + + + align:start position:0% + +so we kind of saw this at the uh and the + + align:start position:0% +so we kind of saw this at the uh and the + + + align:start position:0% +so we kind of saw this at the uh and the +proof of the koshy Schwartz inequality + + align:start position:0% +proof of the koshy Schwartz inequality + + + align:start position:0% +proof of the koshy Schwartz inequality +but if I take Lambda times V an inner + + align:start position:0% +but if I take Lambda times V an inner + + + align:start position:0% +but if I take Lambda times V an inner +product Lambda times V this is equal to + + align:start position:0% +product Lambda times V this is equal to + + + align:start position:0% +product Lambda times V this is equal to +Lambda times Lambda bar + + align:start position:0% +Lambda times Lambda bar + + + align:start position:0% +Lambda times Lambda bar +a scalar pulls out of the first entry + + align:start position:0% +a scalar pulls out of the first entry + + + align:start position:0% +a scalar pulls out of the first entry +unphased the second if a scalar is in + + align:start position:0% +unphased the second if a scalar is in + + + align:start position:0% +unphased the second if a scalar is in +the second entry it comes out with a + + align:start position:0% +the second entry it comes out with a + + + align:start position:0% +the second entry it comes out with a +complex conjugate + + align:start position:0% + + + + align:start position:0% + +and then of course for a complex number + + align:start position:0% +and then of course for a complex number + + + align:start position:0% +and then of course for a complex number +times this complex conjugate I get uh + + align:start position:0% +times this complex conjugate I get uh + + + align:start position:0% +times this complex conjugate I get uh +the norm of that or the length of that + + align:start position:0% +the norm of that or the length of that + + + align:start position:0% +the norm of that or the length of that +the absolute value of that complex + + align:start position:0% +the absolute value of that complex + + + align:start position:0% +the absolute value of that complex +number + + align:start position:0% +number + + + align:start position:0% +number +squared so taking the square root of + + align:start position:0% +squared so taking the square root of + + + align:start position:0% +squared so taking the square root of +both sides of this which is equal to + + align:start position:0% +both sides of this which is equal to + + + align:start position:0% +both sides of this which is equal to +this I get that + + align:start position:0% + + + + align:start position:0% + +the ABS the + + align:start position:0% + + + + align:start position:0% + +this quantity here is equal to + + align:start position:0% + + + + align:start position:0% + +the absolute value of Lambda times this + + align:start position:0% +the absolute value of Lambda times this + + + align:start position:0% +the absolute value of Lambda times this +Norm of V + + align:start position:0% +Norm of V + + + align:start position:0% +Norm of V +which proves + + align:start position:0% +which proves + + + align:start position:0% +which proves +homogeneity of + + align:start position:0% +homogeneity of + + + align:start position:0% +homogeneity of +dysfunction on H okay so that all All + + align:start position:0% +dysfunction on H okay so that all All + + + align:start position:0% +dysfunction on H okay so that all All +That Remains to prove that this is an + + align:start position:0% +That Remains to prove that this is an + + + align:start position:0% +That Remains to prove that this is an +actual Norm so I don't have to keep + + align:start position:0% +actual Norm so I don't have to keep + + + align:start position:0% +actual Norm so I don't have to keep +being uh or at least trying to be + + align:start position:0% +being uh or at least trying to be + + + align:start position:0% +being uh or at least trying to be +um + + align:start position:0% +um + + + align:start position:0% +um +careful with what words I'm using + + align:start position:0% +careful with what words I'm using + + + align:start position:0% +careful with what words I'm using +um + + align:start position:0% + + + + align:start position:0% + +will prove that this is a norm + + align:start position:0% + + + + align:start position:0% + +uh okay so now we need to prove the + + align:start position:0% +uh okay so now we need to prove the + + + align:start position:0% +uh okay so now we need to prove the +triangle inequality + + align:start position:0% +triangle inequality + + + align:start position:0% +triangle inequality +yeah you let UV be an H + + align:start position:0% +yeah you let UV be an H + + + align:start position:0% +yeah you let UV be an H +then + + align:start position:0% + + + + align:start position:0% + +I compute U plus v squared this is equal + + align:start position:0% +I compute U plus v squared this is equal + + + align:start position:0% +I compute U plus v squared this is equal +to + + align:start position:0% +to + + + align:start position:0% +to +U plus v u plus v + + align:start position:0% +U plus v u plus v + + + align:start position:0% +U plus v u plus v +which is equal to + + align:start position:0% +which is equal to + + + align:start position:0% +which is equal to +um + + align:start position:0% +um + + + align:start position:0% +um +just how we computed it for uh + + align:start position:0% +just how we computed it for uh + + + align:start position:0% +just how we computed it for uh +you know when we had a t here and a t + + align:start position:0% +you know when we had a t here and a t + + + align:start position:0% +you know when we had a t here and a t +here when we did the proof of the koshy + + align:start position:0% +here when we did the proof of the koshy + + + align:start position:0% +here when we did the proof of the koshy +Schwartz inequality and we'll use this + + align:start position:0% +Schwartz inequality and we'll use this + + + align:start position:0% +Schwartz inequality and we'll use this +identity quite often that the norm of U + + align:start position:0% +identity quite often that the norm of U + + + align:start position:0% +identity quite often that the norm of U +plus v squared is Norm U squared plus + + align:start position:0% +plus v squared is Norm U squared plus + + + align:start position:0% +plus v squared is Norm U squared plus +Norm + + align:start position:0% +Norm + + + align:start position:0% +Norm +B squared plus two times + + align:start position:0% +B squared plus two times + + + align:start position:0% +B squared plus two times +the real part + + align:start position:0% +the real part + + + align:start position:0% +the real part +of u and v the real part of the inner + + align:start position:0% +of u and v the real part of the inner + + + align:start position:0% +of u and v the real part of the inner +product of u and v + + align:start position:0% + + + + align:start position:0% + +okay now this is less than or equal to + + align:start position:0% + + + + align:start position:0% + +RM squared plus v squared + + align:start position:0% +RM squared plus v squared + + + align:start position:0% +RM squared plus v squared +plus the absolute value of the real part + + align:start position:0% + + + + align:start position:0% + +now the absolute value of the real part + + align:start position:0% +now the absolute value of the real part + + + align:start position:0% +now the absolute value of the real part +of a complex number is less than or + + align:start position:0% +of a complex number is less than or + + + align:start position:0% +of a complex number is less than or +equal to the absolute value of that + + align:start position:0% +equal to the absolute value of that + + + align:start position:0% +equal to the absolute value of that +complex number so this is less than or + + align:start position:0% +complex number so this is less than or + + + align:start position:0% +complex number so this is less than or +equal to the absolute value of the inner + + align:start position:0% +equal to the absolute value of the inner + + + align:start position:0% +equal to the absolute value of the inner +product of u and v + + align:start position:0% +product of u and v + + + align:start position:0% +product of u and v +and by koshy Schwartz that let that is + + align:start position:0% +and by koshy Schwartz that let that is + + + align:start position:0% +and by koshy Schwartz that let that is +less than or equal to + + align:start position:0% + + + + align:start position:0% + +so still what I have before plus 2 + + align:start position:0% +so still what I have before plus 2 + + + align:start position:0% +so still what I have before plus 2 +uh + + align:start position:0% + + + + align:start position:0% + +times the inner product of u and v and + + align:start position:0% + + + + align:start position:0% + +um + + align:start position:0% +um + + + align:start position:0% +um +I guess let me go to the next four + + align:start position:0% +I guess let me go to the next four + + + align:start position:0% +I guess let me go to the next four +oh the proof is essentially done + + align:start position:0% + + + + align:start position:0% + +what I had before is + + align:start position:0% +what I had before is + + + align:start position:0% +what I had before is +equal to normal View + + align:start position:0% +equal to normal View + + + align:start position:0% +equal to normal View +plus normal V + + align:start position:0% +plus normal V + + + align:start position:0% +plus normal V +squared + + align:start position:0% + + + + align:start position:0% + +I.E so I had started off with + + align:start position:0% + + + + align:start position:0% + +the norm of U plus v squared and I had + + align:start position:0% +the norm of U plus v squared and I had + + + align:start position:0% +the norm of U plus v squared and I had +proved that's less than or equal to this + + align:start position:0% +proved that's less than or equal to this + + + align:start position:0% +proved that's less than or equal to this +thing here + + align:start position:0% +thing here + + + align:start position:0% +thing here +squared so taking the square root of + + align:start position:0% +squared so taking the square root of + + + align:start position:0% +squared so taking the square root of +both sides I get + + align:start position:0% +both sides I get + + + align:start position:0% +both sides I get +uh + + align:start position:0% +uh + + + align:start position:0% +uh +the norm of U plus v is less than or + + align:start position:0% +the norm of U plus v is less than or + + + align:start position:0% +the norm of U plus v is less than or +equal to the normal view plus the normal + + align:start position:0% +equal to the normal view plus the normal + + + align:start position:0% +equal to the normal view plus the normal +V okay so this thing that I defined + + align:start position:0% +V okay so this thing that I defined + + + align:start position:0% +V okay so this thing that I defined +before is in fact a norm + + align:start position:0% +before is in fact a norm + + + align:start position:0% +before is in fact a norm +and I'm not just using a + + align:start position:0% + + + + align:start position:0% + +that notation to denote an imposter + + align:start position:0% + + + + align:start position:0% + +foreign + + align:start position:0% + + + + align:start position:0% + +using the koshy Schwartz inequality we + + align:start position:0% +using the koshy Schwartz inequality we + + + align:start position:0% +using the koshy Schwartz inequality we +can also prove that taking the inner + + align:start position:0% +can also prove that taking the inner + + + align:start position:0% +can also prove that taking the inner +product is + + align:start position:0% +product is + + + align:start position:0% +product is +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +um + + align:start position:0% +um + + + align:start position:0% +um +you know it's a function on H cross h + + align:start position:0% +you know it's a function on H cross h + + + align:start position:0% +you know it's a function on H cross h +that's continuous Okay so + + align:start position:0% +that's continuous Okay so + + + align:start position:0% +that's continuous Okay so +let me label this as + + align:start position:0% +let me label this as + + + align:start position:0% +let me label this as +continuity + + align:start position:0% + + + + align:start position:0% + +of + + align:start position:0% +of + + + align:start position:0% +of +the inner product + + align:start position:0% +the inner product + + + align:start position:0% +the inner product +so let me state it as the following if + + align:start position:0% +so let me state it as the following if + + + align:start position:0% +so let me state it as the following if +we're in a pre-hilbert space and un + + align:start position:0% +we're in a pre-hilbert space and un + + + align:start position:0% +we're in a pre-hilbert space and un +converges to U + + align:start position:0% +converges to U + + + align:start position:0% +converges to U +and VN converges to B + + align:start position:0% +and VN converges to B + + + align:start position:0% +and VN converges to B +in a + + align:start position:0% + + + + align:start position:0% + +pre-hilbert space + + align:start position:0% + + + + align:start position:0% + +with Norm + + align:start position:0% +with Norm + + + align:start position:0% +with Norm +as defined uh + + align:start position:0% + + + + align:start position:0% + +as before + + align:start position:0% +as before + + + align:start position:0% +as before +right so now we have a norm on a + + align:start position:0% +right so now we have a norm on a + + + align:start position:0% +right so now we have a norm on a +pre-hilward space and so we can Define + + align:start position:0% +pre-hilward space and so we can Define + + + align:start position:0% +pre-hilward space and so we can Define +convergence uh since it's a norm space + + align:start position:0% +convergence uh since it's a norm space + + + align:start position:0% +convergence uh since it's a norm space +um + + align:start position:0% + + + + align:start position:0% + +free Hilbert space H would Norm this + + align:start position:0% +free Hilbert space H would Norm this + + + align:start position:0% +free Hilbert space H would Norm this +then + + align:start position:0% + + + + align:start position:0% + +you and inner product VN + + align:start position:0% +you and inner product VN + + + align:start position:0% +you and inner product VN +converges to + + align:start position:0% +converges to + + + align:start position:0% +converges to +you and our product fee + + align:start position:0% +you and our product fee + + + align:start position:0% +you and our product fee +okay + + align:start position:0% +okay + + + align:start position:0% +okay +um + + align:start position:0% + + + + align:start position:0% + +all right so + + align:start position:0% +all right so + + + align:start position:0% +all right so +why is this + + align:start position:0% + + + + align:start position:0% + +so last time + + align:start position:0% +so last time + + + align:start position:0% +so last time +and the previous proof I mean you know + + align:start position:0% +and the previous proof I mean you know + + + align:start position:0% +and the previous proof I mean you know +we really didn't use the full strength + + align:start position:0% +we really didn't use the full strength + + + align:start position:0% +we really didn't use the full strength +of the coachy Schwartz inequality we + + align:start position:0% +of the coachy Schwartz inequality we + + + align:start position:0% +of the coachy Schwartz inequality we +could have just gotten by with the real + + align:start position:0% +could have just gotten by with the real + + + align:start position:0% +could have just gotten by with the real +part uh having just proven that the real + + align:start position:0% +part uh having just proven that the real + + + align:start position:0% +part uh having just proven that the real +part of the inner product + + align:start position:0% +part of the inner product + + + align:start position:0% +part of the inner product +um + + align:start position:0% +um + + + align:start position:0% +um +is an absolute value less than or equal + + align:start position:0% +is an absolute value less than or equal + + + align:start position:0% +is an absolute value less than or equal +to the inner product of or the product + + align:start position:0% +to the inner product of or the product + + + align:start position:0% +to the inner product of or the product +of the Norms of u and v here we'll + + align:start position:0% +of the Norms of u and v here we'll + + + align:start position:0% +of the Norms of u and v here we'll +actually use the full koshy Schwartz + + align:start position:0% +actually use the full koshy Schwartz + + + align:start position:0% +actually use the full koshy Schwartz +inequality so the proof is quite simple + + align:start position:0% + + + + align:start position:0% + +If U N converges to U + + align:start position:0% +If U N converges to U + + + align:start position:0% +If U N converges to U +and VN converges to B + + align:start position:0% + + + + align:start position:0% + +I.E let me just + + align:start position:0% +I.E let me just + + + align:start position:0% +I.E let me just +spell this out for you + + align:start position:0% +spell this out for you + + + align:start position:0% +spell this out for you +u n minus U converges to zero + + align:start position:0% +u n minus U converges to zero + + + align:start position:0% +u n minus U converges to zero +and Norm of + + align:start position:0% +and Norm of + + + align:start position:0% +and Norm of +VN minus B converges to zero + + align:start position:0% +VN minus B converges to zero + + + align:start position:0% +VN minus B converges to zero +as n converges to as n goes to Infinity + + align:start position:0% +as n converges to as n goes to Infinity + + + align:start position:0% +as n converges to as n goes to Infinity +then + + align:start position:0% + + + + align:start position:0% + +um + + align:start position:0% + + + + align:start position:0% + +we'll use the squeeze theorem + + align:start position:0% +we'll use the squeeze theorem + + + align:start position:0% +we'll use the squeeze theorem +to show that this quantity converges to + + align:start position:0% +to show that this quantity converges to + + + align:start position:0% +to show that this quantity converges to +U + + align:start position:0% +U + + + align:start position:0% +U +in a product with UV so I have to show + + align:start position:0% +in a product with UV so I have to show + + + align:start position:0% +in a product with UV so I have to show +that this quantity here let me not put + + align:start position:0% +that this quantity here let me not put + + + align:start position:0% +that this quantity here let me not put +that we're not in 18 100. + + align:start position:0% +that we're not in 18 100. + + + align:start position:0% +that we're not in 18 100. +typically in 18100 when + + align:start position:0% +typically in 18100 when + + + align:start position:0% +typically in 18100 when +I first started teaching the squeeze + + align:start position:0% +I first started teaching the squeeze + + + align:start position:0% +I first started teaching the squeeze +theorem I always include the lower bound + + align:start position:0% +theorem I always include the lower bound + + + align:start position:0% +theorem I always include the lower bound +but it should be clear that this is + + align:start position:0% +but it should be clear that this is + + + align:start position:0% +but it should be clear that this is +always less than always bigger than or + + align:start position:0% +always less than always bigger than or + + + align:start position:0% +always less than always bigger than or +equal to zero since it's absolute value + + align:start position:0% +equal to zero since it's absolute value + + + align:start position:0% +equal to zero since it's absolute value +or of a complex number + + align:start position:0% +or of a complex number + + + align:start position:0% +or of a complex number +um + + align:start position:0% +um + + + align:start position:0% +um +okay so this is equal to + + align:start position:0% + + + + align:start position:0% + +u n minus u v n plus + + align:start position:0% +u n minus u v n plus + + + align:start position:0% +u n minus u v n plus +um + + align:start position:0% +um + + + align:start position:0% +um +let's see + + align:start position:0% + + + + align:start position:0% + +U and a product v n minus V + + align:start position:0% +U and a product v n minus V + + + align:start position:0% +U and a product v n minus V +and + + align:start position:0% + + + + align:start position:0% + +the triangle inequality now just for the + + align:start position:0% +the triangle inequality now just for the + + + align:start position:0% +the triangle inequality now just for the +you know modulus or absolute value of + + align:start position:0% +you know modulus or absolute value of + + + align:start position:0% +you know modulus or absolute value of +complex numbers that's less than or + + align:start position:0% +complex numbers that's less than or + + + align:start position:0% +complex numbers that's less than or +equal to + + align:start position:0% +equal to + + + align:start position:0% +equal to +u n minus U + + align:start position:0% +u n minus U + + + align:start position:0% +u n minus U +being + + align:start position:0% + + + + align:start position:0% + +Plus + + align:start position:0% + + + + align:start position:0% + +absolute value of U + + align:start position:0% + + + + align:start position:0% + +v n minus V + + align:start position:0% +v n minus V + + + align:start position:0% +v n minus V +okay + + align:start position:0% + + + + align:start position:0% + +and this is less than or equal to by the + + align:start position:0% +and this is less than or equal to by the + + + align:start position:0% +and this is less than or equal to by the +koshy Schwartz inequality + + align:start position:0% +koshy Schwartz inequality + + + align:start position:0% +koshy Schwartz inequality +um + + align:start position:0% + + + + align:start position:0% + +Norm of u n minus U times the norm of VN + + align:start position:0% +Norm of u n minus U times the norm of VN + + + align:start position:0% +Norm of u n minus U times the norm of VN +plus Norm of U + + align:start position:0% +plus Norm of U + + + align:start position:0% +plus Norm of U +is Norm of VN minus + + align:start position:0% +is Norm of VN minus + + + align:start position:0% +is Norm of VN minus +V + + align:start position:0% +V + + + align:start position:0% +V +and now + + align:start position:0% +and now + + + align:start position:0% +and now +um + + align:start position:0% +um + + + align:start position:0% +um +the VNS are so the VNS are converging to + + align:start position:0% +the VNS are so the VNS are converging to + + + align:start position:0% +the VNS are so the VNS are converging to +V + + align:start position:0% +V + + + align:start position:0% +V +and therefore the Norms of the VNS are + + align:start position:0% +and therefore the Norms of the VNS are + + + align:start position:0% +and therefore the Norms of the VNS are +converging to the norm of B right so + + align:start position:0% +converging to the norm of B right so + + + align:start position:0% +converging to the norm of B right so +um + + align:start position:0% + + + + align:start position:0% + +recall that uh + + align:start position:0% + + + + align:start position:0% + +active VN converges to V + + align:start position:0% +active VN converges to V + + + align:start position:0% +active VN converges to V +then + + align:start position:0% +then + + + align:start position:0% +then +form of VN converges to + + align:start position:0% +form of VN converges to + + + align:start position:0% +form of VN converges to +Norma B okay + + align:start position:0% + + + + align:start position:0% + +all right + + align:start position:0% +all right + + + align:start position:0% +all right +um and again so let me add + + align:start position:0% +um and again so let me add + + + align:start position:0% +um and again so let me add +since + + align:start position:0% + + + + align:start position:0% + +one can prove as you do in + + align:start position:0% +one can prove as you do in + + + align:start position:0% +one can prove as you do in +real analysis the following reverse + + align:start position:0% +real analysis the following reverse + + + align:start position:0% +real analysis the following reverse +triangle inequality since if I have two + + align:start position:0% +triangle inequality since if I have two + + + align:start position:0% +triangle inequality since if I have two +vectors A and B in in H + + align:start position:0% +vectors A and B in in H + + + align:start position:0% +vectors A and B in in H +so this just works in any button space + + align:start position:0% +so this just works in any button space + + + align:start position:0% +so this just works in any button space +not necessarily A pre-operate spaced the + + align:start position:0% +not necessarily A pre-operate spaced the + + + align:start position:0% +not necessarily A pre-operate spaced the +absolute value of the difference in + + align:start position:0% +absolute value of the difference in + + + align:start position:0% +absolute value of the difference in +Norms is less than or equal to the norm + + align:start position:0% +Norms is less than or equal to the norm + + + align:start position:0% +Norms is less than or equal to the norm +of the difference + + align:start position:0% +of the difference + + + align:start position:0% +of the difference +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so this is a convergent uh uh sequence + + align:start position:0% +so this is a convergent uh uh sequence + + + align:start position:0% +so this is a convergent uh uh sequence +of real numbers so it must be bounded so + + align:start position:0% +of real numbers so it must be bounded so + + + align:start position:0% +of real numbers so it must be bounded so +I can + + align:start position:0% + + + + align:start position:0% + +say that's less than or equal to times + + align:start position:0% +say that's less than or equal to times + + + align:start position:0% +say that's less than or equal to times +soup of n + + align:start position:0% +soup of n + + + align:start position:0% +soup of n +or let's use a different letter k + + align:start position:0% + + + + align:start position:0% + +times + + align:start position:0% +times + + + align:start position:0% +times +Plus + + align:start position:0% + + + + align:start position:0% + +form of v n minus V times + + align:start position:0% +form of v n minus V times + + + align:start position:0% +form of v n minus V times +Norm of U now + + align:start position:0% + + + + align:start position:0% + +this is a + + align:start position:0% +this is a + + + align:start position:0% +this is a +this is something converging to zero + + align:start position:0% +this is something converging to zero + + + align:start position:0% +this is something converging to zero +times a fixed number this is something + + align:start position:0% +times a fixed number this is something + + + align:start position:0% +times a fixed number this is something +converging to zero times a fixed number + + align:start position:0% +converging to zero times a fixed number + + + align:start position:0% +converging to zero times a fixed number +and therefore this goes to zero as n + + align:start position:0% +and therefore this goes to zero as n + + + align:start position:0% +and therefore this goes to zero as n +goes to infinity and therefore uh the + + align:start position:0% +goes to infinity and therefore uh the + + + align:start position:0% +goes to infinity and therefore uh the +thing which we started with so this + + align:start position:0% +thing which we started with so this + + + align:start position:0% +thing which we started with so this +quantity here an absolute value is less + + align:start position:0% +quantity here an absolute value is less + + + align:start position:0% +quantity here an absolute value is less +than or equal to something converging to + + align:start position:0% +than or equal to something converging to + + + align:start position:0% +than or equal to something converging to +zero and it's also not negative so + + align:start position:0% + + + + align:start position:0% + +therefore I get that + + align:start position:0% + + + + align:start position:0% + +so this is by The Squeeze theorem + + align:start position:0% +so this is by The Squeeze theorem + + + align:start position:0% +so this is by The Squeeze theorem +I.E + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +okay so that's uh + + align:start position:0% + + + + align:start position:0% + +so on uh pre-hilbert space we can define + + align:start position:0% +so on uh pre-hilbert space we can define + + + align:start position:0% +so on uh pre-hilbert space we can define +a norm + + align:start position:0% +a norm + + + align:start position:0% +a norm +using the inner product + + align:start position:0% +using the inner product + + + align:start position:0% +using the inner product +and this inner product is continuous + + align:start position:0% +and this inner product is continuous + + + align:start position:0% +and this inner product is continuous +with respect to this Norm okay because + + align:start position:0% +with respect to this Norm okay because + + + align:start position:0% +with respect to this Norm okay because +once we have a norm we have convergence + + align:start position:0% +once we have a norm we have convergence + + + align:start position:0% +once we have a norm we have convergence +so we can talk about uh once we have a + + align:start position:0% +so we can talk about uh once we have a + + + align:start position:0% +so we can talk about uh once we have a +norm we have a notion of distance so we + + align:start position:0% +norm we have a notion of distance so we + + + align:start position:0% +norm we have a notion of distance so we +can talk about + + align:start position:0% +can talk about + + + align:start position:0% +can talk about +convergence of sequences and you know + + align:start position:0% +convergence of sequences and you know + + + align:start position:0% +convergence of sequences and you know +uh things like that + + align:start position:0% +uh things like that + + + align:start position:0% +uh things like that +so now + + align:start position:0% +so now + + + align:start position:0% +so now +um + + align:start position:0% +um + + + align:start position:0% +um +a pre-hilbert space is what is a + + align:start position:0% + + + + align:start position:0% + +Hilbert space + + align:start position:0% +Hilbert space + + + align:start position:0% +Hilbert space +this is simply a pre-hilbert space which + + align:start position:0% +this is simply a pre-hilbert space which + + + align:start position:0% +this is simply a pre-hilbert space which +is complete with respect to this Norm + + align:start position:0% +is complete with respect to this Norm + + + align:start position:0% +is complete with respect to this Norm +so + + align:start position:0% +so + + + align:start position:0% +so +a + + align:start position:0% + + + + align:start position:0% + +a Hilbert space h + + align:start position:0% +a Hilbert space h + + + align:start position:0% +a Hilbert space h +is a + + align:start position:0% + + + + align:start position:0% + +pre-hilbert space + + align:start position:0% + + + + align:start position:0% + +which is + + align:start position:0% + + + + align:start position:0% + +complete + + align:start position:0% + + + + align:start position:0% + +with respect to + + align:start position:0% + + + + align:start position:0% + +the norm + + align:start position:0% + + + + align:start position:0% + +uh + + align:start position:0% +uh + + + align:start position:0% +uh +with respect to this Norm which again I + + align:start position:0% +with respect to this Norm which again I + + + align:start position:0% +with respect to this Norm which again I +remember was defined as + + align:start position:0% +remember was defined as + + + align:start position:0% +remember was defined as +I stick a vector + + align:start position:0% +I stick a vector + + + align:start position:0% +I stick a vector +the norm of a vector here is equal to + + align:start position:0% +the norm of a vector here is equal to + + + align:start position:0% +the norm of a vector here is equal to +the inner product of the vector with + + align:start position:0% +the inner product of the vector with + + + align:start position:0% +the inner product of the vector with +itself raised to the one-half power + + align:start position:0% +itself raised to the one-half power + + + align:start position:0% +itself raised to the one-half power +all right so this is the new terminology + + align:start position:0% +all right so this is the new terminology + + + align:start position:0% +all right so this is the new terminology +and as we'll see + + align:start position:0% +and as we'll see + + + align:start position:0% +and as we'll see +um + + align:start position:0% +um + + + align:start position:0% +um +or at least we'll + + align:start position:0% +or at least we'll + + + align:start position:0% +or at least we'll +explicitly spell out in the in a form of + + align:start position:0% +explicitly spell out in the in a form of + + + align:start position:0% +explicitly spell out in the in a form of +a theorem but we will see + + align:start position:0% +a theorem but we will see + + + align:start position:0% +a theorem but we will see +probably by the end of this lecture + + align:start position:0% +probably by the end of this lecture + + + align:start position:0% +probably by the end of this lecture +that really there's for + + align:start position:0% +that really there's for + + + align:start position:0% +that really there's for +um + + align:start position:0% +um + + + align:start position:0% +um +a reasonable Hilbert space you're either + + align:start position:0% +a reasonable Hilbert space you're either + + + align:start position:0% +a reasonable Hilbert space you're either +one of two + + align:start position:0% +one of two + + + align:start position:0% +one of two +things so let me first give the examples + + align:start position:0% +things so let me first give the examples + + + align:start position:0% +things so let me first give the examples +the basic examples of + + align:start position:0% +the basic examples of + + + align:start position:0% +the basic examples of +Hilbert space + + align:start position:0% +Hilbert space + + + align:start position:0% +Hilbert space +so for example c n + + align:start position:0% +so for example c n + + + align:start position:0% +so for example c n +which is + + align:start position:0% +which is + + + align:start position:0% +which is +a set of n-tuples how do I denote this + + align:start position:0% + + + + align:start position:0% + +six numbers + + align:start position:0% + + + + align:start position:0% + +where the inner product of two + + align:start position:0% +where the inner product of two + + + align:start position:0% +where the inner product of two +uh vectors + + align:start position:0% +uh vectors + + + align:start position:0% +uh vectors +Z and W is equal to some + + align:start position:0% +Z and W is equal to some + + + align:start position:0% +Z and W is equal to some +J equals 1 to n + + align:start position:0% +J equals 1 to n + + + align:start position:0% +J equals 1 to n +g z J + + align:start position:0% +g z J + + + align:start position:0% +g z J +W J + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +um + + align:start position:0% +um + + + align:start position:0% +um +so this is an example + + align:start position:0% +so this is an example + + + align:start position:0% +so this is an example +of a Hilbert space finite dimensional + + align:start position:0% +of a Hilbert space finite dimensional + + + align:start position:0% +of a Hilbert space finite dimensional +one meaning it's a bionics it's a vector + + align:start position:0% +one meaning it's a bionics it's a vector + + + align:start position:0% +one meaning it's a bionics it's a vector +space of finite Dimension + + align:start position:0% +space of finite Dimension + + + align:start position:0% +space of finite Dimension +um + + align:start position:0% +um + + + align:start position:0% +um +the other example + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +the space middle L2 + + align:start position:0% + + + + align:start position:0% + +this was the space of sequences + + align:start position:0% + + + + align:start position:0% + +um + + align:start position:0% +um + + + align:start position:0% +um +such that + + align:start position:0% + + + + align:start position:0% + +each of these is a complex number + + align:start position:0% +each of these is a complex number + + + align:start position:0% +each of these is a complex number +and + + align:start position:0% + + + + align:start position:0% + +this uh series is convergent is finite + + align:start position:0% +this uh series is convergent is finite + + + align:start position:0% +this uh series is convergent is finite +um some of the absolute value of the AK + + align:start position:0% +um some of the absolute value of the AK + + + align:start position:0% +um some of the absolute value of the AK +squares this is a Hilbert's face as well + + align:start position:0% +squares this is a Hilbert's face as well + + + align:start position:0% +squares this is a Hilbert's face as well +with what's the inner product of two + + align:start position:0% + + + + align:start position:0% + +um + + align:start position:0% +um + + + align:start position:0% +um +elements of little L2 this is the sum + + align:start position:0% +elements of little L2 this is the sum + + + align:start position:0% +elements of little L2 this is the sum +from k equals one to Infinity + + align:start position:0% + + + + align:start position:0% + +of + + align:start position:0% +of + + + align:start position:0% +of +8K BK + + align:start position:0% +8K BK + + + align:start position:0% +8K BK +okay + + align:start position:0% + + + + align:start position:0% + +all right + + align:start position:0% +all right + + + align:start position:0% +all right +um + + align:start position:0% +um + + + align:start position:0% +um +and note so + + align:start position:0% +and note so + + + align:start position:0% +and note so +you know this is uh pretty clear but + + align:start position:0% +you know this is uh pretty clear but + + + align:start position:0% +you know this is uh pretty clear but +note that uh + + align:start position:0% + + + + align:start position:0% + +the norm I get uh by + + align:start position:0% +the norm I get uh by + + + align:start position:0% +the norm I get uh by +um + + align:start position:0% +um + + + align:start position:0% +um +you know from this inner product this is + + align:start position:0% + + + + align:start position:0% + +simply + + align:start position:0% + + + + align:start position:0% + +which + + align:start position:0% + + + + align:start position:0% + +was a little L2 Norm right + + align:start position:0% + + + + align:start position:0% + +okay so + + align:start position:0% +okay so + + + align:start position:0% +okay so +um you know these are two basic examples + + align:start position:0% +um you know these are two basic examples + + + align:start position:0% +um you know these are two basic examples +of + + align:start position:0% + + + + align:start position:0% + +you know a Hilbert space + + align:start position:0% +you know a Hilbert space + + + align:start position:0% +you know a Hilbert space +uh we will in fact show that + + align:start position:0% +uh we will in fact show that + + + align:start position:0% +uh we will in fact show that +um + + align:start position:0% +um + + + align:start position:0% +um +every separable Hilbert space + + align:start position:0% +every separable Hilbert space + + + align:start position:0% +every separable Hilbert space +can be in a inner product and and + + align:start position:0% +can be in a inner product and and + + + align:start position:0% +can be in a inner product and and +therefore a link preserving way + + align:start position:0% +therefore a link preserving way + + + align:start position:0% +therefore a link preserving way +be mapped so that's usually called a + + align:start position:0% +be mapped so that's usually called a + + + align:start position:0% +be mapped so that's usually called a +an isometric isomorphism can be mapped + + align:start position:0% +an isometric isomorphism can be mapped + + + align:start position:0% +an isometric isomorphism can be mapped +isometrically + + align:start position:0% +isometrically + + + align:start position:0% +isometrically +to either see in or little L2 okay so + + align:start position:0% +to either see in or little L2 okay so + + + align:start position:0% +to either see in or little L2 okay so +these two kind of if one wants to go + + align:start position:0% +these two kind of if one wants to go + + + align:start position:0% +these two kind of if one wants to go +about uh you know + + align:start position:0% +about uh you know + + + align:start position:0% +about uh you know +um + + align:start position:0% +um + + + align:start position:0% +um +categorizing all of the possible Hilbert + + align:start position:0% +categorizing all of the possible Hilbert + + + align:start position:0% +categorizing all of the possible Hilbert +spaces as far as separable Hilbert + + align:start position:0% +spaces as far as separable Hilbert + + + align:start position:0% +spaces as far as separable Hilbert +spaces which are kind of the + + align:start position:0% +spaces which are kind of the + + + align:start position:0% +spaces which are kind of the +only reasonable ones + + align:start position:0% + + + + align:start position:0% + +of course come you know one can come up + + align:start position:0% +of course come you know one can come up + + + align:start position:0% +of course come you know one can come up +with wild examples of + + align:start position:0% +with wild examples of + + + align:start position:0% +with wild examples of +Hilbert's faces which are not then these + + align:start position:0% +Hilbert's faces which are not then these + + + align:start position:0% +Hilbert's faces which are not then these +are the only two I shouldn't say two + + align:start position:0% +are the only two I shouldn't say two + + + align:start position:0% +are the only two I shouldn't say two +because you know this one's indexed by + + align:start position:0% +because you know this one's indexed by + + + align:start position:0% +because you know this one's indexed by +its Dimension but these are the only two + + align:start position:0% +its Dimension but these are the only two + + + align:start position:0% +its Dimension but these are the only two +types that you come up with either a + + align:start position:0% +types that you come up with either a + + + align:start position:0% +types that you come up with either a +finite dimensional uh CN or it's + + align:start position:0% +finite dimensional uh CN or it's + + + align:start position:0% +finite dimensional uh CN or it's +isometric to little L2 okay + + align:start position:0% +isometric to little L2 okay + + + align:start position:0% +isometric to little L2 okay +but um + + align:start position:0% + + + + align:start position:0% + +so but I will still you know write down + + align:start position:0% +so but I will still you know write down + + + align:start position:0% +so but I will still you know write down +another example for + + align:start position:0% +another example for + + + align:start position:0% +another example for +um + + align:start position:0% + + + + align:start position:0% + +since we went to all that work + + align:start position:0% +since we went to all that work + + + align:start position:0% +since we went to all that work +if e is a measurable + + align:start position:0% + + + + align:start position:0% + +subset of r + + align:start position:0% + + + + align:start position:0% + +2 of e the big L2 of e which + + align:start position:0% +2 of e the big L2 of e which + + + align:start position:0% +2 of e the big L2 of e which +remember this was a + + align:start position:0% + + + + align:start position:0% + +space of measurable functions F from E + + align:start position:0% +space of measurable functions F from E + + + align:start position:0% +space of measurable functions F from E +to C such that + + align:start position:0% +to C such that + + + align:start position:0% +to C such that +F squared e is finite + + align:start position:0% +F squared e is finite + + + align:start position:0% +F squared e is finite +this is also + + align:start position:0% +this is also + + + align:start position:0% +this is also +um + + align:start position:0% + + + + align:start position:0% + +this is a Hilbert space what's the inner + + align:start position:0% +this is a Hilbert space what's the inner + + + align:start position:0% +this is a Hilbert space what's the inner +product + + align:start position:0% + + + + align:start position:0% + +with the the inner product of + + align:start position:0% +with the the inner product of + + + align:start position:0% +with the the inner product of +two elements in L2 defined to be + + align:start position:0% +two elements in L2 defined to be + + + align:start position:0% +two elements in L2 defined to be +kind of just the analog of little L2 + + align:start position:0% +kind of just the analog of little L2 + + + align:start position:0% +kind of just the analog of little L2 +where we replace the sum with an + + align:start position:0% +where we replace the sum with an + + + align:start position:0% +where we replace the sum with an +integral + + align:start position:0% +integral + + + align:start position:0% +integral +times G + + align:start position:0% +times G + + + align:start position:0% +times G +okay the label integral of f times + + align:start position:0% +okay the label integral of f times + + + align:start position:0% +okay the label integral of f times +um + + align:start position:0% +um + + + align:start position:0% +um +the complex conjugate of G + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +now um + + align:start position:0% +now um + + + align:start position:0% +now um +you know I wrote down Capital L2 I wrote + + align:start position:0% +you know I wrote down Capital L2 I wrote + + + align:start position:0% +you know I wrote down Capital L2 I wrote +down little L2 + + align:start position:0% +down little L2 + + + align:start position:0% +down little L2 +um + + align:start position:0% +um + + + align:start position:0% +um +but what about the other little LP and + + align:start position:0% +but what about the other little LP and + + + align:start position:0% +but what about the other little LP and +and big LP spaces or any of those + + align:start position:0% +and big LP spaces or any of those + + + align:start position:0% +and big LP spaces or any of those +Hilbert spaces + + align:start position:0% +Hilbert spaces + + + align:start position:0% +Hilbert spaces +um you know so + + align:start position:0% +um you know so + + + align:start position:0% +um you know so +of course if I Define the inner product + + align:start position:0% +of course if I Define the inner product + + + align:start position:0% +of course if I Define the inner product +in this way + + align:start position:0% +in this way + + + align:start position:0% +in this way +um + + align:start position:0% +um + + + align:start position:0% +um +as I did before then that only induces + + align:start position:0% +as I did before then that only induces + + + align:start position:0% +as I did before then that only induces +you know the little L2 and the big L2 + + align:start position:0% +you know the little L2 and the big L2 + + + align:start position:0% +you know the little L2 and the big L2 +Norm right but is there + + align:start position:0% +Norm right but is there + + + align:start position:0% +Norm right but is there +perhaps some other kind of magic inner + + align:start position:0% +perhaps some other kind of magic inner + + + align:start position:0% +perhaps some other kind of magic inner +product out there that I can put on + + align:start position:0% +product out there that I can put on + + + align:start position:0% +product out there that I can put on +little LP or big LP + + align:start position:0% +little LP or big LP + + + align:start position:0% +little LP or big LP +so that I would get out + + align:start position:0% +so that I would get out + + + align:start position:0% +so that I would get out +uh + + align:start position:0% +uh + + + align:start position:0% +uh +the little LP or big LP Norm when I + + align:start position:0% +the little LP or big LP Norm when I + + + align:start position:0% +the little LP or big LP Norm when I +Define the norm according to you know + + align:start position:0% +Define the norm according to you know + + + align:start position:0% +Define the norm according to you know +how I've been doing it + + align:start position:0% +how I've been doing it + + + align:start position:0% +how I've been doing it +um so the question + + align:start position:0% +um so the question + + + align:start position:0% +um so the question +you know on hand is uh + + align:start position:0% + + + + align:start position:0% + +the other little LP or big LP + + align:start position:0% + + + + align:start position:0% + +spaces + + align:start position:0% + + + + align:start position:0% + +also Hilbert spaces + + align:start position:0% + + + + align:start position:0% + +right so again it's clear that if I were + + align:start position:0% +right so again it's clear that if I were + + + align:start position:0% +right so again it's clear that if I were +to define the inner product in in the + + align:start position:0% +to define the inner product in in the + + + align:start position:0% +to define the inner product in in the +way I did in the two examples then that + + align:start position:0% +way I did in the two examples then that + + + align:start position:0% +way I did in the two examples then that +only is going to give the the L2 Norm + + align:start position:0% +only is going to give the the L2 Norm + + + align:start position:0% +only is going to give the the L2 Norm +I'm asking now is there some magical + + align:start position:0% +I'm asking now is there some magical + + + align:start position:0% +I'm asking now is there some magical +inner product I can Define on these + + align:start position:0% +inner product I can Define on these + + + align:start position:0% +inner product I can Define on these +spaces + + align:start position:0% +spaces + + + align:start position:0% +spaces +that spits out the little LP or big LP + + align:start position:0% +that spits out the little LP or big LP + + + align:start position:0% +that spits out the little LP or big LP +Norm right + + align:start position:0% +Norm right + + + align:start position:0% +Norm right +um so the answer is no and there's in + + align:start position:0% +um so the answer is no and there's in + + + align:start position:0% +um so the answer is no and there's in +fact + + align:start position:0% +fact + + + align:start position:0% +fact +you know a way + + align:start position:0% +you know a way + + + align:start position:0% +you know a way +to determine whether or not + + align:start position:0% +to determine whether or not + + + align:start position:0% +to determine whether or not +a space is a Hilbert space because if + + align:start position:0% +a space is a Hilbert space because if + + + align:start position:0% +a space is a Hilbert space because if +you think about it the way you know + + align:start position:0% +you think about it the way you know + + + align:start position:0% +you think about it the way you know +we've come about + + align:start position:0% +we've come about + + + align:start position:0% +we've come about +um + + align:start position:0% + + + + align:start position:0% + +you know introducing uh what a + + align:start position:0% +you know introducing uh what a + + + align:start position:0% +you know introducing uh what a +pre-opered space is and the Hilbert + + align:start position:0% +pre-opered space is and the Hilbert + + + align:start position:0% +pre-opered space is and the Hilbert +space is we first had a norm in our hand + + align:start position:0% +space is we first had a norm in our hand + + + align:start position:0% +space is we first had a norm in our hand +and then we defined an inner product + + align:start position:0% +and then we defined an inner product + + + align:start position:0% +and then we defined an inner product +well if that's the way you're building + + align:start position:0% +well if that's the way you're building + + + align:start position:0% +well if that's the way you're building +your space and you know automatically + + align:start position:0% +your space and you know automatically + + + align:start position:0% +your space and you know automatically +that it's a Hilbert space because you + + align:start position:0% +that it's a Hilbert space because you + + + align:start position:0% +that it's a Hilbert space because you +had an inner product first and then you + + align:start position:0% +had an inner product first and then you + + + align:start position:0% +had an inner product first and then you +defined the norm second let's suppose + + align:start position:0% +defined the norm second let's suppose + + + align:start position:0% +defined the norm second let's suppose +you're only given the data you're given + + align:start position:0% +you're only given the data you're given + + + align:start position:0% +you're only given the data you're given +is some Norm on the space + + align:start position:0% +is some Norm on the space + + + align:start position:0% +is some Norm on the space +when can you determine if that Norm + + align:start position:0% +when can you determine if that Norm + + + align:start position:0% +when can you determine if that Norm +comes from an inner product right that's + + align:start position:0% +comes from an inner product right that's + + + align:start position:0% +comes from an inner product right that's +the question that uh you know is + + align:start position:0% +the question that uh you know is + + + align:start position:0% +the question that uh you know is +underlying this question I wrote on the + + align:start position:0% +underlying this question I wrote on the + + + align:start position:0% +underlying this question I wrote on the +board if I have a norm space + + align:start position:0% +board if I have a norm space + + + align:start position:0% +board if I have a norm space +right so all my initial data is the norm + + align:start position:0% +right so all my initial data is the norm + + + align:start position:0% +right so all my initial data is the norm +when can I tell that that Norm comes + + align:start position:0% +when can I tell that that Norm comes + + + align:start position:0% +when can I tell that that Norm comes +from an inner product + + align:start position:0% +from an inner product + + + align:start position:0% +from an inner product +and um + + align:start position:0% +and um + + + align:start position:0% +and um +it so you'll + + align:start position:0% + + + + align:start position:0% + +prove this basically by direct + + align:start position:0% +prove this basically by direct + + + align:start position:0% +prove this basically by direct +calculation but + + align:start position:0% + + + + align:start position:0% + +this is the following parallelogram + + align:start position:0% + + + + align:start position:0% + +law which is the following if + + align:start position:0% + + + + align:start position:0% + +H is a + + align:start position:0% + + + + align:start position:0% + +pre-hilbert space + + align:start position:0% + + + + align:start position:0% + +then + + align:start position:0% +then + + + align:start position:0% +then +all u v and H + + align:start position:0% +all u v and H + + + align:start position:0% +all u v and H +if I take + + align:start position:0% +if I take + + + align:start position:0% +if I take +the norm of U plus v squared + + align:start position:0% +the norm of U plus v squared + + + align:start position:0% +the norm of U plus v squared +and I add the norm of U minus V squared + + align:start position:0% +and I add the norm of U minus V squared + + + align:start position:0% +and I add the norm of U minus V squared +this is equal to twice + + align:start position:0% +this is equal to twice + + + align:start position:0% +this is equal to twice +the norm of U squared plus the norm + + align:start position:0% +the norm of U squared plus the norm + + + align:start position:0% +the norm of U squared plus the norm +of V squared right so this is a + + align:start position:0% +of V squared right so this is a + + + align:start position:0% +of V squared right so this is a +condition + + align:start position:0% +condition + + + align:start position:0% +condition +um + + align:start position:0% +um + + + align:start position:0% +um +that is stated purely in terms of the + + align:start position:0% +that is stated purely in terms of the + + + align:start position:0% +that is stated purely in terms of the +norm right + + align:start position:0% + + + + align:start position:0% + +moreover uh + + align:start position:0% + + + + align:start position:0% + +if + + align:start position:0% +if + + + align:start position:0% +if +H is a + + align:start position:0% + + + + align:start position:0% + +Norm space + + align:start position:0% + + + + align:start position:0% + +satisfying star + + align:start position:0% + + + + align:start position:0% + +then H is a + + align:start position:0% +then H is a + + + align:start position:0% +then H is a +pre-hilbert space + + align:start position:0% + + + + align:start position:0% + +okay in other words uh + + align:start position:0% +okay in other words uh + + + align:start position:0% +okay in other words uh +although it seems like you know we + + align:start position:0% +although it seems like you know we + + + align:start position:0% +although it seems like you know we +defined Hilbert spaces or pre-hilbert + + align:start position:0% +defined Hilbert spaces or pre-hilbert + + + align:start position:0% +defined Hilbert spaces or pre-hilbert +spaces initially in terms of an inner + + align:start position:0% +spaces initially in terms of an inner + + + align:start position:0% +spaces initially in terms of an inner +product in fact you can say a norm space + + align:start position:0% +product in fact you can say a norm space + + + align:start position:0% +product in fact you can say a norm space +is a pre-hubert space if and only if it + + align:start position:0% +is a pre-hubert space if and only if it + + + align:start position:0% +is a pre-hubert space if and only if it +satisfies this parallelogram law + + align:start position:0% +satisfies this parallelogram law + + + align:start position:0% +satisfies this parallelogram law +okay so if you have on your hands just + + align:start position:0% +okay so if you have on your hands just + + + align:start position:0% +okay so if you have on your hands just +the norm + + align:start position:0% +the norm + + + align:start position:0% +the norm +then + + align:start position:0% +then + + + align:start position:0% +then +as long as that Norm satisfies this + + align:start position:0% +as long as that Norm satisfies this + + + align:start position:0% +as long as that Norm satisfies this +identity that Norm can be derived from + + align:start position:0% +identity that Norm can be derived from + + + align:start position:0% +identity that Norm can be derived from +an inner product + + align:start position:0% +an inner product + + + align:start position:0% +an inner product +so using this theorem you can check that + + align:start position:0% +so using this theorem you can check that + + + align:start position:0% +so using this theorem you can check that +uh + + align:start position:0% + + + + align:start position:0% + +the answer is only for + + align:start position:0% +the answer is only for + + + align:start position:0% +the answer is only for +P equals 2. + + align:start position:0% +P equals 2. + + + align:start position:0% +P equals 2. +okay so in other words if you you can + + align:start position:0% +okay so in other words if you you can + + + align:start position:0% +okay so in other words if you you can +come up with u and v + + align:start position:0% +come up with u and v + + + align:start position:0% +come up with u and v +that so that this inequality is not + + align:start position:0% +that so that this inequality is not + + + align:start position:0% +that so that this inequality is not +satisfied when p is not equal to two + + align:start position:0% +satisfied when p is not equal to two + + + align:start position:0% +satisfied when p is not equal to two +okay + + align:start position:0% + + + + align:start position:0% + +okay so this + + align:start position:0% +okay so this + + + align:start position:0% +okay so this +um + + align:start position:0% + + + + align:start position:0% + +so now we have the notion of a Hilbert + + align:start position:0% +so now we have the notion of a Hilbert + + + align:start position:0% +so now we have the notion of a Hilbert +space + + align:start position:0% +space + + + align:start position:0% +space +where this Norm uh given in terms of an + + align:start position:0% +where this Norm uh given in terms of an + + + align:start position:0% +where this Norm uh given in terms of an +inner product + + align:start position:0% +inner product + + + align:start position:0% +inner product +the space is complete + + align:start position:0% +the space is complete + + + align:start position:0% +the space is complete +now + + align:start position:0% +now + + + align:start position:0% +now +we have an inner product so + + align:start position:0% +we have an inner product so + + + align:start position:0% +we have an inner product so +we can + + align:start position:0% +we can + + + align:start position:0% +we can +start + + align:start position:0% + + + + align:start position:0% + +talking about + + align:start position:0% +talking about + + + align:start position:0% +talking about +um + + align:start position:0% +um + + + align:start position:0% +um +vectors being orthogonal to other + + align:start position:0% +vectors being orthogonal to other + + + align:start position:0% +vectors being orthogonal to other +vectors or + + align:start position:0% +vectors or + + + align:start position:0% +vectors or +or the normal + + align:start position:0% + + + + align:start position:0% + +sets + + align:start position:0% +sets + + + align:start position:0% +sets +um which you know when I first started + + align:start position:0% +um which you know when I first started + + + align:start position:0% +um which you know when I first started +lecturing about this stuff I started I + + align:start position:0% +lecturing about this stuff I started I + + + align:start position:0% +lecturing about this stuff I started I +was already using the terminology this + + align:start position:0% +was already using the terminology this + + + align:start position:0% +was already using the terminology this +thing being orthogonal to this thing or + + align:start position:0% +thing being orthogonal to this thing or + + + align:start position:0% +thing being orthogonal to this thing or +something like that + + align:start position:0% +something like that + + + align:start position:0% +something like that +um + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +of course if you don't remember what + + align:start position:0% +of course if you don't remember what + + + align:start position:0% +of course if you don't remember what +those words mean + + align:start position:0% +those words mean + + + align:start position:0% +those words mean +um from + + align:start position:0% +um from + + + align:start position:0% +um from +linear algebra I'll brief I'll quickly + + align:start position:0% +linear algebra I'll brief I'll quickly + + + align:start position:0% +linear algebra I'll brief I'll quickly +remind you + + align:start position:0% +remind you + + + align:start position:0% +remind you +so suppose we're in a hill pre-hilbert + + align:start position:0% +so suppose we're in a hill pre-hilbert + + + align:start position:0% +so suppose we're in a hill pre-hilbert +space + + align:start position:0% + + + + align:start position:0% + +we say that two elements u and v are + + align:start position:0% +we say that two elements u and v are + + + align:start position:0% +we say that two elements u and v are +orthogonal + + align:start position:0% + + + + align:start position:0% + +if their inner product is zero + + align:start position:0% +if their inner product is zero + + + align:start position:0% +if their inner product is zero +right and we + + align:start position:0% +right and we + + + align:start position:0% +right and we +if uh instead of saying orthogonal I + + align:start position:0% +if uh instead of saying orthogonal I + + + align:start position:0% +if uh instead of saying orthogonal I +want to write this in words I'll write + + align:start position:0% +want to write this in words I'll write + + + align:start position:0% +want to write this in words I'll write +you Purp + + align:start position:0% +you Purp + + + align:start position:0% +you Purp +V + + align:start position:0% +V + + + align:start position:0% +V +okay + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +throughout H is going to be uh + + align:start position:0% +throughout H is going to be uh + + + align:start position:0% +throughout H is going to be uh +pre-hubert's face if I don't actually + + align:start position:0% +pre-hubert's face if I don't actually + + + align:start position:0% +pre-hubert's face if I don't actually +write it if H is a + + align:start position:0% + + + + align:start position:0% + +pre-hilbert space + + align:start position:0% + + + + align:start position:0% + +a subset + + align:start position:0% + + + + align:start position:0% + +um + + align:start position:0% +um + + + align:start position:0% +um +which I'll denote by Eden Lambda Lambda + + align:start position:0% +which I'll denote by Eden Lambda Lambda + + + align:start position:0% +which I'll denote by Eden Lambda Lambda +and Capital Lambda so just some subset + + align:start position:0% +and Capital Lambda so just some subset + + + align:start position:0% +and Capital Lambda so just some subset +indexed by some indexing set Capital + + align:start position:0% +indexed by some indexing set Capital + + + align:start position:0% +indexed by some indexing set Capital +Lambda + + align:start position:0% + + + + align:start position:0% + +we say this set is orthonormal + + align:start position:0% + + + + align:start position:0% + +if + + align:start position:0% +if + + + align:start position:0% +if +we're all Lambda each one of these + + align:start position:0% +we're all Lambda each one of these + + + align:start position:0% +we're all Lambda each one of these +vectors and the subset has unit length + + align:start position:0% + + + + align:start position:0% + +and + + align:start position:0% +and + + + align:start position:0% +and +I need to + + align:start position:0% +I need to + + + align:start position:0% +I need to +uh + + align:start position:0% + + + + align:start position:0% + +different indexed + + align:start position:0% + + + + align:start position:0% + +elements implies that + + align:start position:0% + + + + align:start position:0% + +they are orthogonal + + align:start position:0% +they are orthogonal + + + align:start position:0% +they are orthogonal +okay + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +um maybe this notation scares you + + align:start position:0% +um maybe this notation scares you + + + align:start position:0% +um maybe this notation scares you +because what's this indexing set + + align:start position:0% +because what's this indexing set + + + align:start position:0% +because what's this indexing set +typically we just use the natural number + + align:start position:0% +typically we just use the natural number + + + align:start position:0% +typically we just use the natural number +so let me just make that remark although + + align:start position:0% +so let me just make that remark although + + + align:start position:0% +so let me just make that remark although +I'll make a few remarks in general about + + align:start position:0% +I'll make a few remarks in general about + + + align:start position:0% +I'll make a few remarks in general about +what the normal sets that are not + + align:start position:0% +what the normal sets that are not + + + align:start position:0% +what the normal sets that are not +necessarily indexed by the natural + + align:start position:0% +necessarily indexed by the natural + + + align:start position:0% +necessarily indexed by the natural +numbers will mainly be interested + + align:start position:0% + + + + align:start position:0% + +and you know a finite + + align:start position:0% +and you know a finite + + + align:start position:0% +and you know a finite +set + + align:start position:0% + + + + align:start position:0% + +or accountably infinite set + + align:start position:0% + + + + align:start position:0% + +okay so mainly so although uh an + + align:start position:0% +okay so mainly so although uh an + + + align:start position:0% +okay so mainly so although uh an +orthonormal uh subset of H is + + align:start position:0% +orthonormal uh subset of H is + + + align:start position:0% +orthonormal uh subset of H is +you know could be a very crazy type of + + align:start position:0% +you know could be a very crazy type of + + + align:start position:0% +you know could be a very crazy type of +uh subset mainly we're going to be + + align:start position:0% +uh subset mainly we're going to be + + + align:start position:0% +uh subset mainly we're going to be +interested only in + + align:start position:0% +interested only in + + + align:start position:0% +interested only in +finite or countable + + align:start position:0% +finite or countable + + + align:start position:0% +finite or countable +um + + align:start position:0% +um + + + align:start position:0% +um +accountably infinite uh orthonormal sets + + align:start position:0% + + + + align:start position:0% + +so what's uh + + align:start position:0% +so what's uh + + + align:start position:0% +so what's uh +what are some examples + + align:start position:0% + + + + align:start position:0% + +okay so + + align:start position:0% +okay so + + + align:start position:0% +okay so +um simplest examples + + align:start position:0% + + + + align:start position:0% + +ah if + + align:start position:0% +ah if + + + align:start position:0% +ah if +so + + align:start position:0% + + + + align:start position:0% + +this is uh + + align:start position:0% + + + + align:start position:0% + +an example of a set of orthonormal or an + + align:start position:0% +an example of a set of orthonormal or an + + + align:start position:0% +an example of a set of orthonormal or an +orthonormal subset of C2 or + + align:start position:0% + + + + align:start position:0% + +let's say one + + align:start position:0% + + + + align:start position:0% + +this is also an example of an + + align:start position:0% +this is also an example of an + + + align:start position:0% +this is also an example of an +orthonormal subset of C3 + + align:start position:0% +orthonormal subset of C3 + + + align:start position:0% +orthonormal subset of C3 +um + + align:start position:0% +um + + + align:start position:0% +um +let's say + + align:start position:0% +let's say + + + align:start position:0% +let's say +uh + + align:start position:0% +uh + + + align:start position:0% +uh +using notation from before if I denote + + align:start position:0% +using notation from before if I denote + + + align:start position:0% +using notation from before if I denote +by E sub n this is uh the sequence + + align:start position:0% +by E sub n this is uh the sequence + + + align:start position:0% +by E sub n this is uh the sequence +consisting of zeros up until I hit the + + align:start position:0% +consisting of zeros up until I hit the + + + align:start position:0% +consisting of zeros up until I hit the +end spot + + align:start position:0% +end spot + + + align:start position:0% +end spot +and then 0 afterwards + + align:start position:0% + + + + align:start position:0% + +and entry + + align:start position:0% +and entry + + + align:start position:0% +and entry +uh + + align:start position:0% +uh + + + align:start position:0% +uh +which is an element of little L2 + + align:start position:0% +which is an element of little L2 + + + align:start position:0% +which is an element of little L2 +then + + align:start position:0% + + + + align:start position:0% + +this is an orthonormal subset of L2 + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +one other + + align:start position:0% +one other + + + align:start position:0% +one other +example + + align:start position:0% + + + + align:start position:0% + +is + + align:start position:0% +is + + + align:start position:0% +is +let's look at the functions one over + + align:start position:0% +let's look at the functions one over + + + align:start position:0% +let's look at the functions one over +square root of 2 pi times e to the I and + + align:start position:0% +square root of 2 pi times e to the I and + + + align:start position:0% +square root of 2 pi times e to the I and +X + + align:start position:0% +X + + + align:start position:0% +X +and let's think of these as elements of + + align:start position:0% +and let's think of these as elements of + + + align:start position:0% +and let's think of these as elements of +L2 and minus pi to Pi + + align:start position:0% + + + + align:start position:0% + +then + + align:start position:0% +then + + + align:start position:0% +then +um + + align:start position:0% + + + + align:start position:0% + +this is an orthonormal subset of + + align:start position:0% + + + + align:start position:0% + +my right o-n instead of orthonorm + + align:start position:0% +my right o-n instead of orthonorm + + + align:start position:0% +my right o-n instead of orthonorm +instead of writing out uh orthonormal + + align:start position:0% +instead of writing out uh orthonormal + + + align:start position:0% +instead of writing out uh orthonormal +but this is an orthonormal subset of L2 + + align:start position:0% +but this is an orthonormal subset of L2 + + + align:start position:0% +but this is an orthonormal subset of L2 +right since uh if I take the inner + + align:start position:0% +right since uh if I take the inner + + + align:start position:0% +right since uh if I take the inner +product of + + align:start position:0% + + + + align:start position:0% + +two of these guys I get + + align:start position:0% + + + + align:start position:0% + +let's say I just look at uh two + + align:start position:0% +let's say I just look at uh two + + + align:start position:0% +let's say I just look at uh two +different ones + + align:start position:0% +different ones + + + align:start position:0% +different ones +um + + align:start position:0% + + + + align:start position:0% + +M does not equal n so then I take the + + align:start position:0% +M does not equal n so then I take the + + + align:start position:0% +M does not equal n so then I take the +inner product of i m x + + align:start position:0% +inner product of i m x + + + align:start position:0% +inner product of i m x +with + + align:start position:0% +with + + + align:start position:0% +with +inner product of + + align:start position:0% +inner product of + + + align:start position:0% +inner product of +i n x complex conjugate + + align:start position:0% +i n x complex conjugate + + + align:start position:0% +i n x complex conjugate +so that's the inner product on big L2 + + align:start position:0% +so that's the inner product on big L2 + + + align:start position:0% +so that's the inner product on big L2 +and this is equal to + + align:start position:0% +and this is equal to + + + align:start position:0% +and this is equal to +1 over + + align:start position:0% +1 over + + + align:start position:0% +1 over +2 pi times minus pi to Pi of now if m + + align:start position:0% +2 pi times minus pi to Pi of now if m + + + align:start position:0% +2 pi times minus pi to Pi of now if m +equals n then this I just get the length + + align:start position:0% +equals n then this I just get the length + + + align:start position:0% +equals n then this I just get the length +of e to the i m in n x squared the + + align:start position:0% +of e to the i m in n x squared the + + + align:start position:0% +of e to the i m in n x squared the +length of e to the i m x is 1 and + + align:start position:0% +length of e to the i m x is 1 and + + + align:start position:0% +length of e to the i m x is 1 and +therefore I would just get one here DX + + align:start position:0% +therefore I would just get one here DX + + + align:start position:0% +therefore I would just get one here DX +over 2 pi which gives me 1. but now + + align:start position:0% +over 2 pi which gives me 1. but now + + + align:start position:0% +over 2 pi which gives me 1. but now +they're eight they're not equal so I get + + align:start position:0% +they're eight they're not equal so I get + + + align:start position:0% +they're eight they're not equal so I get +e to the I + + align:start position:0% +e to the I + + + align:start position:0% +e to the I +M minus n x + + align:start position:0% + + + + align:start position:0% + +DX and + + align:start position:0% + + + + align:start position:0% + +now the integral of this creature so + + align:start position:0% +now the integral of this creature so + + + align:start position:0% +now the integral of this creature so +here + + align:start position:0% +here + + + align:start position:0% +here +e to the I let's say + + align:start position:0% +e to the I let's say + + + align:start position:0% +e to the I let's say +I'm going to come up with some e to the + + align:start position:0% +I'm going to come up with some e to the + + + align:start position:0% +I'm going to come up with some e to the +I + + align:start position:0% + + + + align:start position:0% + +y when Y is a real number this is by + + align:start position:0% +y when Y is a real number this is by + + + align:start position:0% +y when Y is a real number this is by +definition cosine of y plus I sine y + + align:start position:0% + + + + align:start position:0% + +now you can check that fundamental + + align:start position:0% +now you can check that fundamental + + + align:start position:0% +now you can check that fundamental +theorem of calculus still holds for uh e + + align:start position:0% +theorem of calculus still holds for uh e + + + align:start position:0% +theorem of calculus still holds for uh e +to the i m minus n over X and this + + align:start position:0% +to the i m minus n over X and this + + + align:start position:0% +to the i m minus n over X and this +equals e to the i m minus n + + align:start position:0% +equals e to the i m minus n + + + align:start position:0% +equals e to the i m minus n +X over I times M minus n + + align:start position:0% +X over I times M minus n + + + align:start position:0% +X over I times M minus n +and uh e to the i m minus n times x is 2 + + align:start position:0% +and uh e to the i m minus n times x is 2 + + + align:start position:0% +and uh e to the i m minus n times x is 2 +pi periodic so when I + + align:start position:0% +pi periodic so when I + + + align:start position:0% +pi periodic so when I +evaluated at minus Pi I get the same + + align:start position:0% +evaluated at minus Pi I get the same + + + align:start position:0% +evaluated at minus Pi I get the same +value if I evaluate it at Pi so this + + align:start position:0% +value if I evaluate it at Pi so this + + + align:start position:0% +value if I evaluate it at Pi so this +equals 0. + + align:start position:0% + + + + align:start position:0% + +so that's a + + align:start position:0% +so that's a + + + align:start position:0% +so that's a +or it's the normal subset of big L2 + + align:start position:0% + + + + align:start position:0% + +so you know this collection of vectors + + align:start position:0% +so you know this collection of vectors + + + align:start position:0% +so you know this collection of vectors +and and I'm calling them vectors but + + align:start position:0% +and and I'm calling them vectors but + + + align:start position:0% +and and I'm calling them vectors but +this collection of elements in big L2 + + align:start position:0% +this collection of elements in big L2 + + + align:start position:0% +this collection of elements in big L2 +you know is still countable even though + + align:start position:0% +you know is still countable even though + + + align:start position:0% +you know is still countable even though +I'm indexing it by the integers rather + + align:start position:0% +I'm indexing it by the integers rather + + + align:start position:0% +I'm indexing it by the integers rather +than the natural numbers + + align:start position:0% + + + + align:start position:0% + +foreign + + align:start position:0% +foreign + + + align:start position:0% +foreign +okay so we have the following + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +now you know most of what I'm going to + + align:start position:0% +now you know most of what I'm going to + + + align:start position:0% +now you know most of what I'm going to +say with regards to + + align:start position:0% +say with regards to + + + align:start position:0% +say with regards to +um accountable subsets of + + align:start position:0% +um accountable subsets of + + + align:start position:0% +um accountable subsets of +um + + align:start position:0% + + + + align:start position:0% + +so accountable orthonormal sets + + align:start position:0% +so accountable orthonormal sets + + + align:start position:0% +so accountable orthonormal sets +still carries through to possibly + + align:start position:0% +still carries through to possibly + + + align:start position:0% +still carries through to possibly +uncountable orthonormal sets where now + + align:start position:0% +uncountable orthonormal sets where now + + + align:start position:0% +uncountable orthonormal sets where now +you know + + align:start position:0% +you know + + + align:start position:0% +you know +a infinite sum over an uncountable + + align:start position:0% +a infinite sum over an uncountable + + + align:start position:0% +a infinite sum over an uncountable +number of elements has to be defined in + + align:start position:0% +number of elements has to be defined in + + + align:start position:0% +number of elements has to be defined in +a precise way but um + + align:start position:0% +a precise way but um + + + align:start position:0% +a precise way but um +I will really just stick mostly to the + + align:start position:0% +I will really just stick mostly to the + + + align:start position:0% +I will really just stick mostly to the +accountable case and if you're + + align:start position:0% +accountable case and if you're + + + align:start position:0% +accountable case and if you're +interested you can always look that + + align:start position:0% +interested you can always look that + + + align:start position:0% +interested you can always look that +stuff up + + align:start position:0% +stuff up + + + align:start position:0% +stuff up +um + + align:start position:0% +um + + + align:start position:0% +um +so I should say you know + + align:start position:0% + + + + align:start position:0% + +what I haven't said is that + + align:start position:0% +what I haven't said is that + + + align:start position:0% +what I haven't said is that +whether or not the lp spaces let's say + + align:start position:0% +whether or not the lp spaces let's say + + + align:start position:0% +whether or not the lp spaces let's say +over an interval a b or over R are + + align:start position:0% +over an interval a b or over R are + + + align:start position:0% +over an interval a b or over R are +separable + + align:start position:0% +separable + + + align:start position:0% +separable +or not or even over a + + align:start position:0% + + + + align:start position:0% + +or even over a yeah so let's stick to + + align:start position:0% +or even over a yeah so let's stick to + + + align:start position:0% +or even over a yeah so let's stick to +either close and bounded interval over + + align:start position:0% +either close and bounded interval over + + + align:start position:0% +either close and bounded interval over +or r + + align:start position:0% +or r + + + align:start position:0% +or r +um + + align:start position:0% +um + + + align:start position:0% +um +now + + align:start position:0% +now + + + align:start position:0% +now +why are these spaces separable and + + align:start position:0% +why are these spaces separable and + + + align:start position:0% +why are these spaces separable and +meaning they have accountably dense uh + + align:start position:0% +meaning they have accountably dense uh + + + align:start position:0% +meaning they have accountably dense uh +subset + + align:start position:0% +subset + + + align:start position:0% +subset +so including big L2 + + align:start position:0% + + + + align:start position:0% + +the reason is the following so what you + + align:start position:0% +the reason is the following so what you + + + align:start position:0% +the reason is the following so what you +proved + + align:start position:0% +proved + + + align:start position:0% +proved +um + + align:start position:0% +um + + + align:start position:0% +um +in the assignment + + align:start position:0% +in the assignment + + + align:start position:0% +in the assignment +is that the continuous functions are + + align:start position:0% +is that the continuous functions are + + + align:start position:0% +is that the continuous functions are +dense and little and big LP for p + + align:start position:0% +dense and little and big LP for p + + + align:start position:0% +dense and little and big LP for p +between P equals uh + + align:start position:0% +between P equals uh + + + align:start position:0% +between P equals uh +1 to Infinity strictly less than + + align:start position:0% +1 to Infinity strictly less than + + + align:start position:0% +1 to Infinity strictly less than +infinity okay they're not dense in L + + align:start position:0% +infinity okay they're not dense in L + + + align:start position:0% +infinity okay they're not dense in L +Infinity so as long as you stay away + + align:start position:0% +Infinity so as long as you stay away + + + align:start position:0% +Infinity so as long as you stay away +from that they're dense okay + + align:start position:0% +from that they're dense okay + + + align:start position:0% +from that they're dense okay +now + + align:start position:0% +now + + + align:start position:0% +now +um + + align:start position:0% + + + + align:start position:0% + +so continuous functions are dense in LP + + align:start position:0% +so continuous functions are dense in LP + + + align:start position:0% +so continuous functions are dense in LP +now what's one way to approximate a + + align:start position:0% +now what's one way to approximate a + + + align:start position:0% +now what's one way to approximate a +continuous function + + align:start position:0% +continuous function + + + align:start position:0% +continuous function +you can going back to your introductory + + align:start position:0% +you can going back to your introductory + + + align:start position:0% +you can going back to your introductory +analysis class hopefully you covered + + align:start position:0% +analysis class hopefully you covered + + + align:start position:0% +analysis class hopefully you covered +What's called the virus drops + + align:start position:0% +What's called the virus drops + + + align:start position:0% +What's called the virus drops +approximation theorem which says that + + align:start position:0% +approximation theorem which says that + + + align:start position:0% +approximation theorem which says that +for every continuous function you can + + align:start position:0% +for every continuous function you can + + + align:start position:0% +for every continuous function you can +approximate it uniformly on the interval + + align:start position:0% +approximate it uniformly on the interval + + + align:start position:0% +approximate it uniformly on the interval +by a polynomial + + align:start position:0% +by a polynomial + + + align:start position:0% +by a polynomial +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so that shows that polynomials are dense + + align:start position:0% +so that shows that polynomials are dense + + + align:start position:0% +so that shows that polynomials are dense +and all the lp spaces of course not L + + align:start position:0% +and all the lp spaces of course not L + + + align:start position:0% +and all the lp spaces of course not L +Infinity + + align:start position:0% + + + + align:start position:0% + +now + + align:start position:0% +now + + + align:start position:0% +now +how do you go from the set of + + align:start position:0% +how do you go from the set of + + + align:start position:0% +how do you go from the set of +polynomials which is uncountable to a + + align:start position:0% +polynomials which is uncountable to a + + + align:start position:0% +polynomials which is uncountable to a +count of which is dense in LP but is + + align:start position:0% +count of which is dense in LP but is + + + align:start position:0% +count of which is dense in LP but is +uncountable to a countable dense subset + + align:start position:0% +uncountable to a countable dense subset + + + align:start position:0% +uncountable to a countable dense subset +which is density no p + + align:start position:0% +which is density no p + + + align:start position:0% +which is density no p +make everything rational okay the set of + + align:start position:0% +make everything rational okay the set of + + + align:start position:0% +make everything rational okay the set of +polynomials with rational coefficients + + align:start position:0% +polynomials with rational coefficients + + + align:start position:0% +polynomials with rational coefficients +is in fact countable + + align:start position:0% +is in fact countable + + + align:start position:0% +is in fact countable +okay and so + + align:start position:0% +okay and so + + + align:start position:0% +okay and so +and you can approximate every polynomial + + align:start position:0% +and you can approximate every polynomial + + + align:start position:0% +and you can approximate every polynomial +with real coefficients by on a closed + + align:start position:0% +with real coefficients by on a closed + + + align:start position:0% +with real coefficients by on a closed +and bounded uh interval by + + align:start position:0% +and bounded uh interval by + + + align:start position:0% +and bounded uh interval by +a polynomial with rational coefficients + + align:start position:0% +a polynomial with rational coefficients + + + align:start position:0% +a polynomial with rational coefficients +is not too difficult to to believe + + align:start position:0% +is not too difficult to to believe + + + align:start position:0% +is not too difficult to to believe +and therefore the polynomials with + + align:start position:0% +and therefore the polynomials with + + + align:start position:0% +and therefore the polynomials with +rational coefficients + + align:start position:0% +rational coefficients + + + align:start position:0% +rational coefficients +okay are dense and the lp spaces as long + + align:start position:0% +okay are dense and the lp spaces as long + + + align:start position:0% +okay are dense and the lp spaces as long +as I'm not in L Infinity + + align:start position:0% +as I'm not in L Infinity + + + align:start position:0% +as I'm not in L Infinity +um and therefore all the lp spaces are + + align:start position:0% +um and therefore all the lp spaces are + + + align:start position:0% +um and therefore all the lp spaces are +separable + + align:start position:0% + + + + align:start position:0% + +um + + align:start position:0% +um + + + align:start position:0% +um +now + + align:start position:0% +now + + + align:start position:0% +now +the little LP spaces are also separable + + align:start position:0% +the little LP spaces are also separable + + + align:start position:0% +the little LP spaces are also separable +because except for L Infinity also which + + align:start position:0% +because except for L Infinity also which + + + align:start position:0% +because except for L Infinity also which +is not separable + + align:start position:0% +is not separable + + + align:start position:0% +is not separable +um + + align:start position:0% +um + + + align:start position:0% +um +because first off + + align:start position:0% +because first off + + + align:start position:0% +because first off +a dense + + align:start position:0% +a dense + + + align:start position:0% +a dense +subset of the let's say little O2 let's + + align:start position:0% +subset of the let's say little O2 let's + + + align:start position:0% +subset of the let's say little O2 let's +make things definite + + align:start position:0% +make things definite + + + align:start position:0% +make things definite +is the Subspace consisting of all + + align:start position:0% +is the Subspace consisting of all + + + align:start position:0% +is the Subspace consisting of all +sequences which terminate after + + align:start position:0% +sequences which terminate after + + + align:start position:0% +sequences which terminate after +some entry in other words it's zero + + align:start position:0% +some entry in other words it's zero + + + align:start position:0% +some entry in other words it's zero +after that okay + + align:start position:0% +after that okay + + + align:start position:0% +after that okay +you know convince yourself that this + + align:start position:0% +you know convince yourself that this + + + align:start position:0% +you know convince yourself that this +Subspace of all finitely terminating + + align:start position:0% +Subspace of all finitely terminating + + + align:start position:0% +Subspace of all finitely terminating +sequences this is dense and little LP + + align:start position:0% +sequences this is dense and little LP + + + align:start position:0% +sequences this is dense and little LP +for every uh for p between one and + + align:start position:0% +for every uh for p between one and + + + align:start position:0% +for every uh for p between one and +infinity not equal to Infinity + + align:start position:0% +infinity not equal to Infinity + + + align:start position:0% +infinity not equal to Infinity +okay so finitely terminating sequences + + align:start position:0% +okay so finitely terminating sequences + + + align:start position:0% +okay so finitely terminating sequences +are dense and little LP + + align:start position:0% +are dense and little LP + + + align:start position:0% +are dense and little LP +um + + align:start position:0% +um + + + align:start position:0% +um +unfortunately that's again an + + align:start position:0% +unfortunately that's again an + + + align:start position:0% +unfortunately that's again an +uncountable uh + + align:start position:0% +uncountable uh + + + align:start position:0% +uncountable uh +I mean it's a it's a Subspace so it's + + align:start position:0% +I mean it's a it's a Subspace so it's + + + align:start position:0% +I mean it's a it's a Subspace so it's +going to be uncountable + + align:start position:0% +going to be uncountable + + + align:start position:0% +going to be uncountable +so how do I get now accountable thing + + align:start position:0% +so how do I get now accountable thing + + + align:start position:0% +so how do I get now accountable thing +again I replace everything by rational + + align:start position:0% +again I replace everything by rational + + + align:start position:0% +again I replace everything by rational +numbers so if I uh I can approximate + + align:start position:0% +numbers so if I uh I can approximate + + + align:start position:0% +numbers so if I uh I can approximate +every sequence which terminates after a + + align:start position:0% +every sequence which terminates after a + + + align:start position:0% +every sequence which terminates after a +certain point + + align:start position:0% +certain point + + + align:start position:0% +certain point +consisting of real numbers by a sequence + + align:start position:0% +consisting of real numbers by a sequence + + + align:start position:0% +consisting of real numbers by a sequence +full of just rationals terminating after + + align:start position:0% +full of just rationals terminating after + + + align:start position:0% +full of just rationals terminating after +a certain point + + align:start position:0% +a certain point + + + align:start position:0% +a certain point +by just choosing the rationals very + + align:start position:0% +by just choosing the rationals very + + + align:start position:0% +by just choosing the rationals very +close to those real numbers right we're + + align:start position:0% +close to those real numbers right we're + + + align:start position:0% +close to those real numbers right we're +using here and I said didn't say this + + align:start position:0% +using here and I said didn't say this + + + align:start position:0% +using here and I said didn't say this +explicitly a minute ago that you know we + + align:start position:0% +explicitly a minute ago that you know we + + + align:start position:0% +explicitly a minute ago that you know we +still have we have the density of the + + align:start position:0% +still have we have the density of the + + + align:start position:0% +still have we have the density of the +rationals and the reels for every reel I + + align:start position:0% +rationals and the reels for every reel I + + + align:start position:0% +rationals and the reels for every reel I +can find a rational very close to it + + align:start position:0% +can find a rational very close to it + + + align:start position:0% +can find a rational very close to it +okay so + + align:start position:0% +okay so + + + align:start position:0% +okay so +um + + align:start position:0% +um + + + align:start position:0% +um +you know this is kind of thinking that + + align:start position:0% +you know this is kind of thinking that + + + align:start position:0% +you know this is kind of thinking that +goes in goes on so but now the set of + + align:start position:0% +goes in goes on so but now the set of + + + align:start position:0% +goes in goes on so but now the set of +all finitely terminating sequences with + + align:start position:0% +all finitely terminating sequences with + + + align:start position:0% +all finitely terminating sequences with +rational coefficients this is a + + align:start position:0% +rational coefficients this is a + + + align:start position:0% +rational coefficients this is a +countable set + + align:start position:0% +countable set + + + align:start position:0% +countable set +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and that countable set is dense and + + align:start position:0% +and that countable set is dense and + + + align:start position:0% +and that countable set is dense and +little LP and therefore little LP is + + align:start position:0% +little LP and therefore little LP is + + + align:start position:0% +little LP and therefore little LP is +separable as long as p is between one + + align:start position:0% +separable as long as p is between one + + + align:start position:0% +separable as long as p is between one +and Infinity uh excluding Infinity okay + + align:start position:0% +and Infinity uh excluding Infinity okay + + + align:start position:0% +and Infinity uh excluding Infinity okay +so + + align:start position:0% +so + + + align:start position:0% +so +um + + align:start position:0% +um + + + align:start position:0% +um +you know I said at the beginning that + + align:start position:0% +you know I said at the beginning that + + + align:start position:0% +you know I said at the beginning that +we're going to be mainly interested in + + align:start position:0% +we're going to be mainly interested in + + + align:start position:0% +we're going to be mainly interested in +in separable spaces without actually + + align:start position:0% +in separable spaces without actually + + + align:start position:0% +in separable spaces without actually +saying why little LP or little L2 and + + align:start position:0% +saying why little LP or little L2 and + + + align:start position:0% +saying why little LP or little L2 and +big L2 are separable + + align:start position:0% +big L2 are separable + + + align:start position:0% +big L2 are separable +um + + align:start position:0% +um + + + align:start position:0% +um +but uh so I just gave you the argument + + align:start position:0% +but uh so I just gave you the argument + + + align:start position:0% +but uh so I just gave you the argument +by word + + align:start position:0% +by word + + + align:start position:0% +by word +of mouth now instead of actually writing + + align:start position:0% +of mouth now instead of actually writing + + + align:start position:0% +of mouth now instead of actually writing +it down Okay so + + align:start position:0% +it down Okay so + + + align:start position:0% +it down Okay so +um + + align:start position:0% + + + + align:start position:0% + +we have the following vessels inequality + + align:start position:0% +we have the following vessels inequality + + + align:start position:0% +we have the following vessels inequality +for + + align:start position:0% + + + + align:start position:0% + +orthonormal accountable orthonormal + + align:start position:0% +orthonormal accountable orthonormal + + + align:start position:0% +orthonormal accountable orthonormal +subsets so + + align:start position:0% +subsets so + + + align:start position:0% +subsets so +if + + align:start position:0% +if + + + align:start position:0% +if +the n + + align:start position:0% +the n + + + align:start position:0% +the n +is well let me just put n here if this + + align:start position:0% +is well let me just put n here if this + + + align:start position:0% +is well let me just put n here if this +is a + + align:start position:0% + + + + align:start position:0% + +countable + + align:start position:0% +countable + + + align:start position:0% +countable +meaning it's either finite or it's + + align:start position:0% +meaning it's either finite or it's + + + align:start position:0% +meaning it's either finite or it's +countably infinite + + align:start position:0% + + + + align:start position:0% + +but it's countable + + align:start position:0% +but it's countable + + + align:start position:0% +but it's countable +uh orthonormal subset + + align:start position:0% + + + + align:start position:0% + +a pre-hilbert's face + + align:start position:0% + + + + align:start position:0% + +h + + align:start position:0% + + + + align:start position:0% + +and for all U and H + + align:start position:0% +and for all U and H + + + align:start position:0% +and for all U and H +if I look at the sum of squares U and a + + align:start position:0% +if I look at the sum of squares U and a + + + align:start position:0% +if I look at the sum of squares U and a +product e sub n + + align:start position:0% +product e sub n + + + align:start position:0% +product e sub n +this is less than or equal to + + align:start position:0% + + + + align:start position:0% + +the norm of U squared + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +um + + align:start position:0% +um + + + align:start position:0% +um +so our discussion here of orthonormal + + align:start position:0% +so our discussion here of orthonormal + + + align:start position:0% +so our discussion here of orthonormal +subsets is taking place within a + + align:start position:0% +subsets is taking place within a + + + align:start position:0% +subsets is taking place within a +pre-hilbert space + + align:start position:0% +pre-hilbert space + + + align:start position:0% +pre-hilbert space +um + + align:start position:0% +um + + + align:start position:0% +um +don't need Hilbert spaces to talk about + + align:start position:0% +don't need Hilbert spaces to talk about + + + align:start position:0% +don't need Hilbert spaces to talk about +these Concepts uh yeah but when we're in + + align:start position:0% +these Concepts uh yeah but when we're in + + + align:start position:0% +these Concepts uh yeah but when we're in +a Hilbert space and we have a certain + + align:start position:0% +a Hilbert space and we have a certain + + + align:start position:0% +a Hilbert space and we have a certain +orthonormal subset that will be + + align:start position:0% +orthonormal subset that will be + + + align:start position:0% +orthonormal subset that will be +important that that we're in the Hilbert + + align:start position:0% +important that that we're in the Hilbert + + + align:start position:0% +important that that we're in the Hilbert +space + + align:start position:0% +space + + + align:start position:0% +space +okay so uh + + align:start position:0% + + + + align:start position:0% + +the proof is + + align:start position:0% +the proof is + + + align:start position:0% +the proof is +uh let's do the finite case first + + align:start position:0% + + + + align:start position:0% + +so uh + + align:start position:0% + + + + align:start position:0% + +suppose I have + + align:start position:0% +suppose I have + + + align:start position:0% +suppose I have +finite collection of orthonormal or + + align:start position:0% +finite collection of orthonormal or + + + align:start position:0% +finite collection of orthonormal or +finite orthonormal subset of H or a fine + + align:start position:0% +finite orthonormal subset of H or a fine + + + align:start position:0% +finite orthonormal subset of H or a fine +or I'll often say finite collection of + + align:start position:0% +or I'll often say finite collection of + + + align:start position:0% +or I'll often say finite collection of +orthonormal vectors in H + + align:start position:0% + + + + align:start position:0% + +no end subset of H + + align:start position:0% +no end subset of H + + + align:start position:0% +no end subset of H +again o n + + align:start position:0% +again o n + + + align:start position:0% +again o n +standing in for orthonormal + + align:start position:0% + + + + align:start position:0% + +then let me just record a few identities + + align:start position:0% +then let me just record a few identities + + + align:start position:0% +then let me just record a few identities +which are pretty easy to verify + + align:start position:0% +which are pretty easy to verify + + + align:start position:0% +which are pretty easy to verify +some from n equals 1 to n of U inner + + align:start position:0% +some from n equals 1 to n of U inner + + + align:start position:0% +some from n equals 1 to n of U inner +product e n e n + + align:start position:0% +product e n e n + + + align:start position:0% +product e n e n +um + + align:start position:0% +um + + + align:start position:0% +um +if I take the norm of this thing squared + + align:start position:0% + + + + align:start position:0% + +let's compute this out this is the inner + + align:start position:0% +let's compute this out this is the inner + + + align:start position:0% +let's compute this out this is the inner +product of + + align:start position:0% +product of + + + align:start position:0% +product of +with the understanding that n is going + + align:start position:0% +with the understanding that n is going + + + align:start position:0% +with the understanding that n is going +from one to capital n + + align:start position:0% + + + + align:start position:0% + +let's use a different index here + + align:start position:0% + + + + align:start position:0% + +and this is equal to n m + + align:start position:0% +and this is equal to n m + + + align:start position:0% +and this is equal to n m +u e n + + align:start position:0% +u e n + + + align:start position:0% +u e n +uh + + align:start position:0% +uh + + + align:start position:0% +uh +now I have this sum here of + + align:start position:0% +now I have this sum here of + + + align:start position:0% +now I have this sum here of +I should leaving out e in + + align:start position:0% + + + + align:start position:0% + +of u b m + + align:start position:0% +of u b m + + + align:start position:0% +of u b m +complex conjugate times the inner + + align:start position:0% +complex conjugate times the inner + + + align:start position:0% +complex conjugate times the inner +product of e n with e m that's the two + + align:start position:0% +product of e n with e m that's the two + + + align:start position:0% +product of e n with e m that's the two +vectors that are taking the complex + + align:start position:0% +vectors that are taking the complex + + + align:start position:0% +vectors that are taking the complex +complex conjugate of this is a number + + align:start position:0% +complex conjugate of this is a number + + + align:start position:0% +complex conjugate of this is a number +here it just comes out this number here + + align:start position:0% +here it just comes out this number here + + + align:start position:0% +here it just comes out this number here +gets hit with a complex conjugate when + + align:start position:0% +gets hit with a complex conjugate when + + + align:start position:0% +gets hit with a complex conjugate when +it comes out now the inner product of En + + align:start position:0% +it comes out now the inner product of En + + + align:start position:0% +it comes out now the inner product of En +with em is 0 when n does not equal m and + + align:start position:0% +with em is 0 when n does not equal m and + + + align:start position:0% +with em is 0 when n does not equal m and +is equal to one because it's equal to + + align:start position:0% +is equal to one because it's equal to + + + align:start position:0% +is equal to one because it's equal to +the norm of E N squared when n equals m + + align:start position:0% +the norm of E N squared when n equals m + + + align:start position:0% +the norm of E N squared when n equals m +so all I pick up from this double sum + + align:start position:0% +so all I pick up from this double sum + + + align:start position:0% +so all I pick up from this double sum +which is just a finite double sum is + + align:start position:0% + + + + align:start position:0% + +when n equals m + + align:start position:0% +when n equals m + + + align:start position:0% +when n equals m +and N going from one to n + + align:start position:0% +and N going from one to n + + + align:start position:0% +and N going from one to n +uh + + align:start position:0% + + + + align:start position:0% + +and therefore this is equal to + + align:start position:0% + + + + align:start position:0% + +u e n + + align:start position:0% +u e n + + + align:start position:0% +u e n +squared + + align:start position:0% +squared + + + align:start position:0% +squared +okay + + align:start position:0% +okay + + + align:start position:0% +okay +[Applause] + + align:start position:0% + + + + align:start position:0% + +foreign + + align:start position:0% + + + + align:start position:0% + +that's one + + align:start position:0% + + + + align:start position:0% + +formula I want to have another one is + + align:start position:0% +formula I want to have another one is + + + align:start position:0% +formula I want to have another one is +that if I take the inner product of U + + align:start position:0% +that if I take the inner product of U + + + align:start position:0% +that if I take the inner product of U +with n equals 1 to n + + align:start position:0% + + + + align:start position:0% + +of + + align:start position:0% +of + + + align:start position:0% +of +the sum and you know maybe you recognize + + align:start position:0% +the sum and you know maybe you recognize + + + align:start position:0% +the sum and you know maybe you recognize +what this uh sum here actually is I'll + + align:start position:0% +what this uh sum here actually is I'll + + + align:start position:0% +what this uh sum here actually is I'll +say so in a minute so this is equal to + + align:start position:0% +say so in a minute so this is equal to + + + align:start position:0% +say so in a minute so this is equal to +sum from n equals one + + align:start position:0% +sum from n equals one + + + align:start position:0% +sum from n equals one +to n of so + + align:start position:0% +to n of so + + + align:start position:0% +to n of so +U and a product e sub n times this + + align:start position:0% +U and a product e sub n times this + + + align:start position:0% +U and a product e sub n times this +number this number comes out and gives + + align:start position:0% +number this number comes out and gives + + + align:start position:0% +number this number comes out and gives +me a complex conjugate + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +and therefore + + align:start position:0% + + + + align:start position:0% + +zero which is bigger than or equal to + + align:start position:0% +zero which is bigger than or equal to + + + align:start position:0% +zero which is bigger than or equal to +the norm of U minus + + align:start position:0% +the norm of U minus + + + align:start position:0% +the norm of U minus +n equals 1 to n of + + align:start position:0% +n equals 1 to n of + + + align:start position:0% +n equals 1 to n of +u e n e n + + align:start position:0% +u e n e n + + + align:start position:0% +u e n e n +now if you remember back from linear + + align:start position:0% +now if you remember back from linear + + + align:start position:0% +now if you remember back from linear +algebra from calculus that if I have + + align:start position:0% +algebra from calculus that if I have + + + align:start position:0% +algebra from calculus that if I have +um + + align:start position:0% +um + + + align:start position:0% +um +orthonormal vectors and I have a vector + + align:start position:0% +orthonormal vectors and I have a vector + + + align:start position:0% +orthonormal vectors and I have a vector +U this quantity is nothing but the + + align:start position:0% +U this quantity is nothing but the + + + align:start position:0% +U this quantity is nothing but the +projection of U onto the span of those + + align:start position:0% +projection of U onto the span of those + + + align:start position:0% +projection of U onto the span of those +orthonormal vectors okay + + align:start position:0% +orthonormal vectors okay + + + align:start position:0% +orthonormal vectors okay +so what I'm looking at here is + + align:start position:0% +so what I'm looking at here is + + + align:start position:0% +so what I'm looking at here is +if you like + + align:start position:0% +if you like + + + align:start position:0% +if you like +the norm of the part of you that's + + align:start position:0% +the norm of the part of you that's + + + align:start position:0% +the norm of the part of you that's +orthogonal to these finitely many + + align:start position:0% +orthogonal to these finitely many + + + align:start position:0% +orthogonal to these finitely many +vectors + + align:start position:0% +vectors + + + align:start position:0% +vectors +okay + + align:start position:0% + + + + align:start position:0% + +okay so this thing's bigger than or + + align:start position:0% +okay so this thing's bigger than or + + + align:start position:0% +okay so this thing's bigger than or +equal to zero we use that formula of how + + align:start position:0% +equal to zero we use that formula of how + + + align:start position:0% +equal to zero we use that formula of how +to compute the norm of something plus + + align:start position:0% +to compute the norm of something plus + + + align:start position:0% +to compute the norm of something plus +something and this is equal to Norm of U + + align:start position:0% +something and this is equal to Norm of U + + + align:start position:0% +something and this is equal to Norm of U +squared plus Norm + + align:start position:0% +squared plus Norm + + + align:start position:0% +squared plus Norm +equals one to n u e n e n + + align:start position:0% +equals one to n u e n e n + + + align:start position:0% +equals one to n u e n e n +squared minus 2 times the real part of U + + align:start position:0% +squared minus 2 times the real part of U + + + align:start position:0% +squared minus 2 times the real part of U +inner product + + align:start position:0% +inner product + + + align:start position:0% +inner product +sum from n equals 1 to n of U + + align:start position:0% +sum from n equals 1 to n of U + + + align:start position:0% +sum from n equals 1 to n of U +e n a n + + align:start position:0% + + + + align:start position:0% + +okay and now we know what all of these + + align:start position:0% +okay and now we know what all of these + + + align:start position:0% +okay and now we know what all of these +things are this is equal to uh I'm not + + align:start position:0% +things are this is equal to uh I'm not + + + align:start position:0% +things are this is equal to uh I'm not +even going to go over this is equal to + + align:start position:0% +even going to go over this is equal to + + + align:start position:0% +even going to go over this is equal to +this no this quantity here as is this + + align:start position:0% +this no this quantity here as is this + + + align:start position:0% +this no this quantity here as is this +inner product it's also equal to this + + align:start position:0% +inner product it's also equal to this + + + align:start position:0% +inner product it's also equal to this +thing here so the real part is equal to + + align:start position:0% +thing here so the real part is equal to + + + align:start position:0% +thing here so the real part is equal to +this thing here because this is a real + + align:start position:0% +this thing here because this is a real + + + align:start position:0% +this thing here because this is a real +number and I get since this comes with a + + align:start position:0% +number and I get since this comes with a + + + align:start position:0% +number and I get since this comes with a +2 I cancel one of those so I get normal + + align:start position:0% +2 I cancel one of those so I get normal + + + align:start position:0% +2 I cancel one of those so I get normal +View + + align:start position:0% +View + + + align:start position:0% +View +squared minus sum from n equals 1 to n + + align:start position:0% +squared minus sum from n equals 1 to n + + + align:start position:0% +squared minus sum from n equals 1 to n +of U + + align:start position:0% +of U + + + align:start position:0% +of U +e n + + align:start position:0% +e n + + + align:start position:0% +e n +Square + + align:start position:0% +Square + + + align:start position:0% +Square +okay which is exactly what I wanted to + + align:start position:0% +okay which is exactly what I wanted to + + + align:start position:0% +okay which is exactly what I wanted to +prove for the finite case + + align:start position:0% + + + + align:start position:0% + +but the infinite case then follows from + + align:start position:0% +but the infinite case then follows from + + + align:start position:0% +but the infinite case then follows from +the finite case + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% + + + + align:start position:0% + +um + + align:start position:0% +um + + + align:start position:0% +um +and by letting capital N Go to Infinity + + align:start position:0% +and by letting capital N Go to Infinity + + + align:start position:0% +and by letting capital N Go to Infinity +so infinite case + + align:start position:0% +so infinite case + + + align:start position:0% +so infinite case +suppose + + align:start position:0% +suppose + + + align:start position:0% +suppose +e n + + align:start position:0% +e n + + + align:start position:0% +e n +equals 1 to Infinity is + + align:start position:0% + + + + align:start position:0% + +orthonormal subset + + align:start position:0% + + + + align:start position:0% + +h + + align:start position:0% +h + + + align:start position:0% +h +then we know that for all n capital n + + align:start position:0% + + + + align:start position:0% + +we have that + + align:start position:0% +we have that + + + align:start position:0% +we have that +sum Over N equals 1 to n of u e n + + align:start position:0% + + + + align:start position:0% + +this is less than or equal to + + align:start position:0% +this is less than or equal to + + + align:start position:0% +this is less than or equal to +the norm of U squared so I can just send + + align:start position:0% +the norm of U squared so I can just send + + + align:start position:0% +the norm of U squared so I can just send +capital n + + align:start position:0% +capital n + + + align:start position:0% +capital n +to Infinity to get that the sum + + align:start position:0% + + + + align:start position:0% + +equals 1 to Infinity of Norm of U + + align:start position:0% +equals 1 to Infinity of Norm of U + + + align:start position:0% +equals 1 to Infinity of Norm of U +E N squared is less than or equal to + + align:start position:0% +E N squared is less than or equal to + + + align:start position:0% +E N squared is less than or equal to +U squared + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +um + + align:start position:0% +um + + + align:start position:0% +um +so + + align:start position:0% +so + + + align:start position:0% +so +orthonormal subsets + + align:start position:0% +orthonormal subsets + + + align:start position:0% +orthonormal subsets +we can Define + + align:start position:0% +we can Define + + + align:start position:0% +we can Define +as you know a collection of vectors that + + align:start position:0% +as you know a collection of vectors that + + + align:start position:0% +as you know a collection of vectors that +have unit length and are mutually + + align:start position:0% +have unit length and are mutually + + + align:start position:0% +have unit length and are mutually +orthogonal + + align:start position:0% +orthogonal + + + align:start position:0% +orthogonal +to each other + + align:start position:0% +to each other + + + align:start position:0% +to each other +um + + align:start position:0% + + + + align:start position:0% + +now just orthonormal subsets + + align:start position:0% +now just orthonormal subsets + + + align:start position:0% +now just orthonormal subsets +list any old orthonormal subset is not + + align:start position:0% +list any old orthonormal subset is not + + + align:start position:0% +list any old orthonormal subset is not +really the most + + align:start position:0% +really the most + + + align:start position:0% +really the most +useful thing + + align:start position:0% + + + + align:start position:0% + +if we're trying to study the entire + + align:start position:0% +if we're trying to study the entire + + + align:start position:0% +if we're trying to study the entire +Hilbert's or pre-hubble pre-hilbert + + align:start position:0% +Hilbert's or pre-hubble pre-hilbert + + + align:start position:0% +Hilbert's or pre-hubble pre-hilbert +space h + + align:start position:0% + + + + align:start position:0% + +because we may miss something if we + + align:start position:0% +because we may miss something if we + + + align:start position:0% +because we may miss something if we +leave out certain + + align:start position:0% +leave out certain + + + align:start position:0% +leave out certain +orthonormal vectors + + align:start position:0% + + + + align:start position:0% + +um + + align:start position:0% +um + + + align:start position:0% +um +so + + align:start position:0% +so + + + align:start position:0% +so +but a more useful + + align:start position:0% +but a more useful + + + align:start position:0% +but a more useful +um + + align:start position:0% +um + + + align:start position:0% +um +type of orthonormal + + align:start position:0% +type of orthonormal + + + align:start position:0% +type of orthonormal +effect is a maximal orthonormal set or + + align:start position:0% +effect is a maximal orthonormal set or + + + align:start position:0% +effect is a maximal orthonormal set or +which is defined as follows + + align:start position:0% +which is defined as follows + + + align:start position:0% +which is defined as follows +an orthonormal subset + + align:start position:0% + + + + align:start position:0% + +e Lambda + + align:start position:0% +e Lambda + + + align:start position:0% +e Lambda +Lambda and capital Lambda of + + align:start position:0% + + + + align:start position:0% + +a pre-hilbert space h + + align:start position:0% + + + + align:start position:0% + +maximal + + align:start position:0% +maximal + + + align:start position:0% +maximal +so again if you know having a possibly + + align:start position:0% +so again if you know having a possibly + + + align:start position:0% +so again if you know having a possibly +uncountable collection of what the + + align:start position:0% +uncountable collection of what the + + + align:start position:0% +uncountable collection of what the +normal subsets indexed by some + + align:start position:0% +normal subsets indexed by some + + + align:start position:0% +normal subsets indexed by some +indexing set makes you uncomfortable + + align:start position:0% +indexing set makes you uncomfortable + + + align:start position:0% +indexing set makes you uncomfortable +replace this with you know in where n is + + align:start position:0% +replace this with you know in where n is + + + align:start position:0% +replace this with you know in where n is +going from one to capital N or n is + + align:start position:0% +going from one to capital N or n is + + + align:start position:0% +going from one to capital N or n is +going from one to infinity and so + + align:start position:0% +going from one to infinity and so + + + align:start position:0% +going from one to infinity and so +accountable collection if you like but + + align:start position:0% +accountable collection if you like but + + + align:start position:0% +accountable collection if you like but +I'm stating this so that + + align:start position:0% +I'm stating this so that + + + align:start position:0% +I'm stating this so that +um + + align:start position:0% +um + + + align:start position:0% +um +you know that uh more something more + + align:start position:0% +you know that uh more something more + + + align:start position:0% +you know that uh more something more +General is true so this is maximal if + + align:start position:0% +General is true so this is maximal if + + + align:start position:0% +General is true so this is maximal if +what + + align:start position:0% +what + + + align:start position:0% +what +um The Following + + align:start position:0% + + + + align:start position:0% + +holds If U is an H + + align:start position:0% +holds If U is an H + + + align:start position:0% +holds If U is an H +and + + align:start position:0% +and + + + align:start position:0% +and +um U is orthogonal + + align:start position:0% +um U is orthogonal + + + align:start position:0% +um U is orthogonal +to everything in this orthonormal subset + + align:start position:0% + + + + align:start position:0% + +this implies that U is zero + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +um + + align:start position:0% + + + + align:start position:0% + +an example of course is + + align:start position:0% + + + + align:start position:0% + +you can check that this collection here + + align:start position:0% +you can check that this collection here + + + align:start position:0% +you can check that this collection here +is + + align:start position:0% + + + + align:start position:0% + +is a maximal + + align:start position:0% + + + + align:start position:0% + +orthonormal subset of C2 + + align:start position:0% +orthonormal subset of C2 + + + align:start position:0% +orthonormal subset of C2 +a non-example right + + align:start position:0% +a non-example right + + + align:start position:0% +a non-example right +you can + + align:start position:0% +you can + + + align:start position:0% +you can +kind of maybe see this coming + + align:start position:0% +kind of maybe see this coming + + + align:start position:0% +kind of maybe see this coming +the one we had a minute ago + + align:start position:0% + + + + align:start position:0% + +this is not maximal + + align:start position:0% + + + + align:start position:0% + +since there's a vector that has inner + + align:start position:0% +since there's a vector that has inner + + + align:start position:0% +since there's a vector that has inner +product zero with both of these but is + + align:start position:0% +product zero with both of these but is + + + align:start position:0% +product zero with both of these but is +non-zero right since + + align:start position:0% +non-zero right since + + + align:start position:0% +non-zero right since +this should be C3 + + align:start position:0% +this should be C3 + + + align:start position:0% +this should be C3 +since + + align:start position:0% +since + + + align:start position:0% +since +um + + align:start position:0% + + + + align:start position:0% + +let me just write it kind of loosely + + align:start position:0% +let me just write it kind of loosely + + + align:start position:0% +let me just write it kind of loosely +this way since this Vector is 0 1 0 is + + align:start position:0% +this way since this Vector is 0 1 0 is + + + align:start position:0% +this way since this Vector is 0 1 0 is +orthogonal to both of these but it's + + align:start position:0% +orthogonal to both of these but it's + + + align:start position:0% +orthogonal to both of these but it's +non-zero right maximal means if you're + + align:start position:0% +non-zero right maximal means if you're + + + align:start position:0% +non-zero right maximal means if you're +orthogonal to everything in your + + align:start position:0% +orthogonal to everything in your + + + align:start position:0% +orthogonal to everything in your +collection then it has to be zero but + + align:start position:0% +collection then it has to be zero but + + + align:start position:0% +collection then it has to be zero but +this is non-zero and it's orthogonal too + + align:start position:0% +this is non-zero and it's orthogonal too + + + align:start position:0% +this is non-zero and it's orthogonal too +um + + align:start position:0% +um + + + align:start position:0% +um +uh everything to these two vectors there + + align:start position:0% +uh everything to these two vectors there + + + align:start position:0% +uh everything to these two vectors there +another example is + + align:start position:0% + + + + align:start position:0% + +you know again + + align:start position:0% +you know again + + + align:start position:0% +you know again +with the notation from before this is + + align:start position:0% +with the notation from before this is + + + align:start position:0% +with the notation from before this is +where this is the sequence that is zero + + align:start position:0% +where this is the sequence that is zero + + + align:start position:0% +where this is the sequence that is zero +except for the end spot where it is one + + align:start position:0% +except for the end spot where it is one + + + align:start position:0% +except for the end spot where it is one +this is + + align:start position:0% +this is + + + align:start position:0% +this is +maximal + + align:start position:0% + + + + align:start position:0% + +orthonormal subset of little L2 + + align:start position:0% +orthonormal subset of little L2 + + + align:start position:0% +orthonormal subset of little L2 +okay + + align:start position:0% + + + + align:start position:0% + +now what we're going to see very shortly + + align:start position:0% +now what we're going to see very shortly + + + align:start position:0% +now what we're going to see very shortly +is that + + align:start position:0% +is that + + + align:start position:0% +is that +um + + align:start position:0% +um + + + align:start position:0% +um +if we have a countably infinite maximal + + align:start position:0% +if we have a countably infinite maximal + + + align:start position:0% +if we have a countably infinite maximal +subset of a Hilbert space then that set + + align:start position:0% +subset of a Hilbert space then that set + + + align:start position:0% +subset of a Hilbert space then that set +serves kind of the same purpose as a + + align:start position:0% +serves kind of the same purpose as a + + + align:start position:0% +serves kind of the same purpose as a +basis as a orthonormal basis does in + + align:start position:0% +basis as a orthonormal basis does in + + + align:start position:0% +basis as a orthonormal basis does in +linear algebra right I mean if you look + + align:start position:0% +linear algebra right I mean if you look + + + align:start position:0% +linear algebra right I mean if you look +at here already you know this + + align:start position:0% +at here already you know this + + + align:start position:0% +at here already you know this +orthonormal set is maximal and it also + + align:start position:0% +orthonormal set is maximal and it also + + + align:start position:0% +orthonormal set is maximal and it also +forms a basis for C2 right this was not + + align:start position:0% +forms a basis for C2 right this was not + + + align:start position:0% +forms a basis for C2 right this was not +maximal and you see it doesn't form a + + align:start position:0% +maximal and you see it doesn't form a + + + align:start position:0% +maximal and you see it doesn't form a +basis for C3 + + align:start position:0% +basis for C3 + + + align:start position:0% +basis for C3 +right so maximal is gonna + + align:start position:0% +right so maximal is gonna + + + align:start position:0% +right so maximal is gonna +kind of give us a + + align:start position:0% +kind of give us a + + + align:start position:0% +kind of give us a +a condition which is is + + align:start position:0% +a condition which is is + + + align:start position:0% +a condition which is is +kind of equally useful as being a basis + + align:start position:0% +kind of equally useful as being a basis + + + align:start position:0% +kind of equally useful as being a basis +but it won't be a Hammel based these + + align:start position:0% +but it won't be a Hammel based these + + + align:start position:0% +but it won't be a Hammel based these +subsets won't be a Hammel basis in the + + align:start position:0% +subsets won't be a Hammel basis in the + + + align:start position:0% +subsets won't be a Hammel basis in the +sense that every Vector can be written + + align:start position:0% +sense that every Vector can be written + + + align:start position:0% +sense that every Vector can be written +as a finite linear combination of the + + align:start position:0% +as a finite linear combination of the + + + align:start position:0% +as a finite linear combination of the +elements of a maximal orthonormal subset + + align:start position:0% +elements of a maximal orthonormal subset + + + align:start position:0% +elements of a maximal orthonormal subset +but what is true is that we can write it + + align:start position:0% +but what is true is that we can write it + + + align:start position:0% +but what is true is that we can write it +as possibly an infinite sum involving uh + + align:start position:0% +as possibly an infinite sum involving uh + + + align:start position:0% +as possibly an infinite sum involving uh +uh the or the maximal or the normal + + align:start position:0% +uh the or the maximal or the normal + + + align:start position:0% +uh the or the maximal or the normal +subset you know which is + + align:start position:0% +subset you know which is + + + align:start position:0% +subset you know which is +in most cases just as uh good if you + + align:start position:0% +in most cases just as uh good if you + + + align:start position:0% +in most cases just as uh good if you +want to use that all right + + align:start position:0% + + + + align:start position:0% + +okay so um first off when + + align:start position:0% +okay so um first off when + + + align:start position:0% +okay so um first off when +does every uh pre-hilbert space have a + + align:start position:0% +does every uh pre-hilbert space have a + + + align:start position:0% +does every uh pre-hilbert space have a +maximal uh + + align:start position:0% +maximal uh + + + align:start position:0% +maximal uh +uh subset + + align:start position:0% +uh subset + + + align:start position:0% +uh subset +so let me State this as a theorem in + + align:start position:0% +so let me State this as a theorem in + + + align:start position:0% +so let me State this as a theorem in +fact it'll state two theorems the first + + align:start position:0% +fact it'll state two theorems the first + + + align:start position:0% +fact it'll state two theorems the first +is uh + + align:start position:0% +is uh + + + align:start position:0% +is uh +every + + align:start position:0% +every + + + align:start position:0% +every +should say + + align:start position:0% + + + + align:start position:0% + +non-trivial + + align:start position:0% +non-trivial + + + align:start position:0% +non-trivial +because we could have the Hilbert space + + align:start position:0% +because we could have the Hilbert space + + + align:start position:0% +because we could have the Hilbert space +the speed the zero Vector Hilbert's + + align:start position:0% +the speed the zero Vector Hilbert's + + + align:start position:0% +the speed the zero Vector Hilbert's +pre-hilbert space + + align:start position:0% + + + + align:start position:0% + +has + + align:start position:0% + + + + align:start position:0% + +maximal + + align:start position:0% +maximal + + + align:start position:0% +maximal +or the normal + + align:start position:0% +or the normal + + + align:start position:0% +or the normal +subset whether it's separable or not it + + align:start position:0% +subset whether it's separable or not it + + + align:start position:0% +subset whether it's separable or not it +has a maximal orthonormal subset and the + + align:start position:0% +has a maximal orthonormal subset and the + + + align:start position:0% +has a maximal orthonormal subset and the +way you prove this is using so I'm not + + align:start position:0% +way you prove this is using so I'm not + + + align:start position:0% +way you prove this is using so I'm not +going to give her proof of this I'm + + align:start position:0% +going to give her proof of this I'm + + + align:start position:0% +going to give her proof of this I'm +going to give you a proof of something a + + align:start position:0% +going to give you a proof of something a + + + align:start position:0% +going to give you a proof of something a +little less strong but about as useful + + align:start position:0% +little less strong but about as useful + + + align:start position:0% +little less strong but about as useful +as as we'll need + + align:start position:0% +as as we'll need + + + align:start position:0% +as as we'll need +um + + align:start position:0% +um + + + align:start position:0% +um +one proves this by uh + + align:start position:0% +one proves this by uh + + + align:start position:0% +one proves this by uh +the by using Zorn's Lemma + + align:start position:0% +the by using Zorn's Lemma + + + align:start position:0% +the by using Zorn's Lemma +by you know taking a set your set that + + align:start position:0% +by you know taking a set your set that + + + align:start position:0% +by you know taking a set your set that +you're going to put a partial order on + + align:start position:0% +you're going to put a partial order on + + + align:start position:0% +you're going to put a partial order on +to be the collections of orthonormal + + align:start position:0% +to be the collections of orthonormal + + + align:start position:0% +to be the collections of orthonormal +bases are not orthonormal bases a Max of + + align:start position:0% +bases are not orthonormal bases a Max of + + + align:start position:0% +bases are not orthonormal bases a Max of +orthonormal subsets and then ordered by + + align:start position:0% +orthonormal subsets and then ordered by + + + align:start position:0% +orthonormal subsets and then ordered by +inclusion and then one can do a Zorn's + + align:start position:0% +inclusion and then one can do a Zorn's + + + align:start position:0% +inclusion and then one can do a Zorn's +Lemma argument and apply Zorn's Lemma to + + align:start position:0% +Lemma argument and apply Zorn's Lemma to + + + align:start position:0% +Lemma argument and apply Zorn's Lemma to +to obtain a maximal + + align:start position:0% +to obtain a maximal + + + align:start position:0% +to obtain a maximal +um + + align:start position:0% +um + + + align:start position:0% +um +orthonormal subset but that's kind of + + align:start position:0% +orthonormal subset but that's kind of + + + align:start position:0% +orthonormal subset but that's kind of +hands off and maybe that scares you a + + align:start position:0% +hands off and maybe that scares you a + + + align:start position:0% +hands off and maybe that scares you a +little bit because uh Zorn's Lemma is a + + align:start position:0% +little bit because uh Zorn's Lemma is a + + + align:start position:0% +little bit because uh Zorn's Lemma is a +equivalent to the Axiom of choice so + + align:start position:0% +equivalent to the Axiom of choice so + + + align:start position:0% +equivalent to the Axiom of choice so +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +if you don't like using the Axiom of + + align:start position:0% +if you don't like using the Axiom of + + + align:start position:0% +if you don't like using the Axiom of +choice maybe you have a problem with + + align:start position:0% +choice maybe you have a problem with + + + align:start position:0% +choice maybe you have a problem with +using it to construct a maximal + + align:start position:0% +using it to construct a maximal + + + align:start position:0% +using it to construct a maximal +orthonormal subset of a + + align:start position:0% +orthonormal subset of a + + + align:start position:0% +orthonormal subset of a +pre-hilbert space but + + align:start position:0% +pre-hilbert space but + + + align:start position:0% +pre-hilbert space but +uh + + align:start position:0% +uh + + + align:start position:0% +uh +we can actually do this by hand if the + + align:start position:0% +we can actually do this by hand if the + + + align:start position:0% +we can actually do this by hand if the +Hilbert space is separable so this is + + align:start position:0% +Hilbert space is separable so this is + + + align:start position:0% +Hilbert space is separable so this is +the theorem will actually prove every uh + + align:start position:0% +the theorem will actually prove every uh + + + align:start position:0% +the theorem will actually prove every uh +non-trivial + + align:start position:0% + + + + align:start position:0% + +um + + align:start position:0% + + + + align:start position:0% + +separable meaning it had meaning the + + align:start position:0% +separable meaning it had meaning the + + + align:start position:0% +separable meaning it had meaning the +pre-hubert space has a countably dense + + align:start position:0% +pre-hubert space has a countably dense + + + align:start position:0% +pre-hubert space has a countably dense +subset every non-trivial separable + + align:start position:0% +subset every non-trivial separable + + + align:start position:0% +subset every non-trivial separable +pre-hilbert space + + align:start position:0% + + + + align:start position:0% + +accountable + + align:start position:0% + + + + align:start position:0% + +maximal + + align:start position:0% +maximal + + + align:start position:0% +maximal +orthonormal subset + + align:start position:0% +orthonormal subset + + + align:start position:0% +orthonormal subset +okay + + align:start position:0% +okay + + + align:start position:0% +okay +which as I said this is kind of the main + + align:start position:0% +which as I said this is kind of the main + + + align:start position:0% +which as I said this is kind of the main +uh + + align:start position:0% + + + + align:start position:0% + +types of orthonormal subsets we'll be + + align:start position:0% +types of orthonormal subsets we'll be + + + align:start position:0% +types of orthonormal subsets we'll be +interested in just because you know + + align:start position:0% +interested in just because you know + + + align:start position:0% +interested in just because you know +defining infinite sums is easier to do + + align:start position:0% +defining infinite sums is easier to do + + + align:start position:0% +defining infinite sums is easier to do +over a countable uh index than it is an + + align:start position:0% +over a countable uh index than it is an + + + align:start position:0% +over a countable uh index than it is an +uncountable index but uh anyways so + + align:start position:0% +uncountable index but uh anyways so + + + align:start position:0% +uncountable index but uh anyways so +we're going to prove and actually + + align:start position:0% +we're going to prove and actually + + + align:start position:0% +we're going to prove and actually +construct this essentially by hand + + align:start position:0% +construct this essentially by hand + + + align:start position:0% +construct this essentially by hand +um using + + align:start position:0% +um using + + + align:start position:0% +um using +uh the process that's the name of this + + align:start position:0% +uh the process that's the name of this + + + align:start position:0% +uh the process that's the name of this +little section the Graham Schmidt + + align:start position:0% +little section the Graham Schmidt + + + align:start position:0% +little section the Graham Schmidt +process + + align:start position:0% + + + + align:start position:0% + +so if you from remember from linear + + align:start position:0% +so if you from remember from linear + + + align:start position:0% +so if you from remember from linear +algebra if you have a collection of + + align:start position:0% +algebra if you have a collection of + + + align:start position:0% +algebra if you have a collection of +um vectors you can always find and + + align:start position:0% +um vectors you can always find and + + + align:start position:0% +um vectors you can always find and +orthonormal collection of vectors that + + align:start position:0% +orthonormal collection of vectors that + + + align:start position:0% +orthonormal collection of vectors that +span uh the Vector space that is spanned + + align:start position:0% +span uh the Vector space that is spanned + + + align:start position:0% +span uh the Vector space that is spanned +by the original set of vectors okay + + align:start position:0% +by the original set of vectors okay + + + align:start position:0% +by the original set of vectors okay +and that's what we'll do + + align:start position:0% + + + + align:start position:0% + +so since H is separable + + align:start position:0% + + + + align:start position:0% + +let be a + + align:start position:0% +let be a + + + align:start position:0% +let be a +countable + + align:start position:0% + + + + align:start position:0% + +dense + + align:start position:0% + + + + align:start position:0% + +subset of + + align:start position:0% +subset of + + + align:start position:0% +subset of +H and it's uh this is a non-trivial + + align:start position:0% +H and it's uh this is a non-trivial + + + align:start position:0% +H and it's uh this is a non-trivial +pre-hubert space so + + align:start position:0% +pre-hubert space so + + + align:start position:0% +pre-hubert space so +we can always make sure that + + align:start position:0% +we can always make sure that + + + align:start position:0% +we can always make sure that +the first one is a non-zero Vector okay + + align:start position:0% +the first one is a non-zero Vector okay + + + align:start position:0% +the first one is a non-zero Vector okay +so uh + + align:start position:0% +so uh + + + align:start position:0% +so uh +you know accountable means dense + + align:start position:0% +you know accountable means dense + + + align:start position:0% +you know accountable means dense +remember means that for any element in h + + align:start position:0% +remember means that for any element in h + + + align:start position:0% +remember means that for any element in h +there exists an element from this + + align:start position:0% +there exists an element from this + + + align:start position:0% +there exists an element from this +sequence uh + + align:start position:0% +sequence uh + + + align:start position:0% +sequence uh +or from this collection that's within + + align:start position:0% +or from this collection that's within + + + align:start position:0% +or from this collection that's within +Epsilon of uh that Vector from h + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% + + + + align:start position:0% + +so now I'm going to make the following + + align:start position:0% +so now I'm going to make the following + + + align:start position:0% +so now I'm going to make the following +claim this is essentially a + + align:start position:0% +claim this is essentially a + + + align:start position:0% +claim this is essentially a +the gram + + align:start position:0% +the gram + + + align:start position:0% +the gram +Schmidt process + + align:start position:0% + + + + align:start position:0% + +which will improve which will approve by + + align:start position:0% +which will improve which will approve by + + + align:start position:0% +which will improve which will approve by +induction + + align:start position:0% +induction + + + align:start position:0% +induction +we're all in + + align:start position:0% +we're all in + + + align:start position:0% +we're all in +natural number + + align:start position:0% + + + + align:start position:0% + +there exists + + align:start position:0% + + + + align:start position:0% + +another integer a natural number M of n + + align:start position:0% + + + + align:start position:0% + +and + + align:start position:0% + + + + align:start position:0% + +and orthonormal + + align:start position:0% + + + + align:start position:0% + +subset + + align:start position:0% +subset + + + align:start position:0% +subset + + align:start position:0% + + + align:start position:0% +up to em + + align:start position:0% + + + + align:start position:0% + +such that + + align:start position:0% +such that + + + align:start position:0% +such that +the following is true + + align:start position:0% +the following is true + + + align:start position:0% +the following is true +um + + align:start position:0% +um + + + align:start position:0% +um +first is + + align:start position:0% + + + + align:start position:0% + +uh + + align:start position:0% +uh + + + align:start position:0% +uh +the span of E1 + + align:start position:0% +the span of E1 + + + align:start position:0% +the span of E1 +up to e m of n + + align:start position:0% +up to e m of n + + + align:start position:0% +up to e m of n +equals + + align:start position:0% +equals + + + align:start position:0% +equals +the span of B1 up to VN + + align:start position:0% + + + + align:start position:0% + +and so you see + + align:start position:0% +and so you see + + + align:start position:0% +and so you see +you know n is changing so maybe for each + + align:start position:0% +you know n is changing so maybe for each + + + align:start position:0% +you know n is changing so maybe for each +time I change N I get a different + + align:start position:0% +time I change N I get a different + + + align:start position:0% +time I change N I get a different +orthonormal subset + + align:start position:0% +orthonormal subset + + + align:start position:0% +orthonormal subset +or a wildly different orthonormal subset + + align:start position:0% +or a wildly different orthonormal subset + + + align:start position:0% +or a wildly different orthonormal subset +from uh + + align:start position:0% +from uh + + + align:start position:0% +from uh +the integer before it but + + align:start position:0% +the integer before it but + + + align:start position:0% +the integer before it but +um so the property of these subsets are + + align:start position:0% +um so the property of these subsets are + + + align:start position:0% +um so the property of these subsets are +that I'm just simply adding a + + align:start position:0% +that I'm just simply adding a + + + align:start position:0% +that I'm just simply adding a +a vector or not so and + + align:start position:0% +a vector or not so and + + + align:start position:0% +a vector or not so and +E1 + + align:start position:0% +E1 + + + align:start position:0% +E1 +to e m of n so this collection is equal + + align:start position:0% +to e m of n so this collection is equal + + + align:start position:0% +to e m of n so this collection is equal +to + + align:start position:0% +to + + + align:start position:0% +to +um + + align:start position:0% +um + + + align:start position:0% +um +the previous collection + + align:start position:0% + + + + align:start position:0% + +Union either the empty set + + align:start position:0% +Union either the empty set + + + align:start position:0% +Union either the empty set +if VN + + align:start position:0% +if VN + + + align:start position:0% +if VN +is in the span of + + align:start position:0% +is in the span of + + + align:start position:0% +is in the span of +the one up to B n minus 1 + + align:start position:0% +the one up to B n minus 1 + + + align:start position:0% +the one up to B n minus 1 +and some new Vector e of M sub n + + align:start position:0% +and some new Vector e of M sub n + + + align:start position:0% +and some new Vector e of M sub n +and I'll tell you what e of M sub n is + + align:start position:0% +and I'll tell you what e of M sub n is + + + align:start position:0% +and I'll tell you what e of M sub n is +it otherwise + + align:start position:0% + + + + align:start position:0% + +okay so what I'm saying here is that I + + align:start position:0% +okay so what I'm saying here is that I + + + align:start position:0% +okay so what I'm saying here is that I +have this countably infinite list of B's + + align:start position:0% +have this countably infinite list of B's + + + align:start position:0% +have this countably infinite list of B's +and for each N I can come up with a + + align:start position:0% +and for each N I can come up with a + + + align:start position:0% +and for each N I can come up with a +finite orthonormal subset + + align:start position:0% +finite orthonormal subset + + + align:start position:0% +finite orthonormal subset +that spans the same span as V1 up to V + + align:start position:0% +that spans the same span as V1 up to V + + + align:start position:0% +that spans the same span as V1 up to V +in and at each stage all I do is add a + + align:start position:0% +in and at each stage all I do is add a + + + align:start position:0% +in and at each stage all I do is add a +vector or not depending on if the next V + + align:start position:0% +vector or not depending on if the next V + + + align:start position:0% +vector or not depending on if the next V +is in the span of the previous or not + + align:start position:0% +is in the span of the previous or not + + + align:start position:0% +is in the span of the previous or not +okay so I hope that's clear + + align:start position:0% +okay so I hope that's clear + + + align:start position:0% +okay so I hope that's clear +um + + align:start position:0% +um + + + align:start position:0% +um +Okay so + + align:start position:0% +Okay so + + + align:start position:0% +Okay so +to prove this by induction so proof of + + align:start position:0% +to prove this by induction so proof of + + + align:start position:0% +to prove this by induction so proof of +claim + + align:start position:0% + + + + align:start position:0% + +this is by induction + + align:start position:0% +this is by induction + + + align:start position:0% +this is by induction +so let's do + + align:start position:0% + + + + align:start position:0% + +the base case n equals one uh + + align:start position:0% + + + + align:start position:0% + +let's take we take E1 to B + + align:start position:0% +let's take we take E1 to B + + + align:start position:0% +let's take we take E1 to B +B1 over + + align:start position:0% +B1 over + + + align:start position:0% +B1 over +length of V + + align:start position:0% +length of V + + + align:start position:0% +length of V +all right + + align:start position:0% +all right + + + align:start position:0% +all right +so now we're started + + align:start position:0% +so now we're started + + + align:start position:0% +so now we're started +now we've got our first + + align:start position:0% +now we've got our first + + + align:start position:0% +now we've got our first +Vector in this list that we're building + + align:start position:0% +Vector in this list that we're building + + + align:start position:0% +Vector in this list that we're building +up + + align:start position:0% + + + + align:start position:0% + +inductive step + + align:start position:0% +inductive step + + + align:start position:0% +inductive step +so + + align:start position:0% +so + + + align:start position:0% +so +um + + align:start position:0% + + + + align:start position:0% + +let's call this what I want to prove + + align:start position:0% +let's call this what I want to prove + + + align:start position:0% +let's call this what I want to prove +star so suppose + + align:start position:0% + + + + align:start position:0% + +the star holds + + align:start position:0% +the star holds + + + align:start position:0% +the star holds +for uh + + align:start position:0% + + + + align:start position:0% + +so this whole claim here I shouldn't say + + align:start position:0% +so this whole claim here I shouldn't say + + + align:start position:0% +so this whole claim here I shouldn't say +Just A and B but the whole claim holds + + align:start position:0% +Just A and B but the whole claim holds + + + align:start position:0% +Just A and B but the whole claim holds +for n equals K and now I want to prove + + align:start position:0% +for n equals K and now I want to prove + + + align:start position:0% +for n equals K and now I want to prove +it holds for n equals K plus one so I + + align:start position:0% +it holds for n equals K plus one so I + + + align:start position:0% +it holds for n equals K plus one so I +wanna + + align:start position:0% +wanna + + + align:start position:0% +wanna +what kind of vector do I need to add to + + align:start position:0% +what kind of vector do I need to add to + + + align:start position:0% +what kind of vector do I need to add to +the previous uh collection of vectors to + + align:start position:0% +the previous uh collection of vectors to + + + align:start position:0% +the previous uh collection of vectors to +now span V1 up to V K plus 1. + + align:start position:0% +now span V1 up to V K plus 1. + + + align:start position:0% +now span V1 up to V K plus 1. +okay + + align:start position:0% + + + + align:start position:0% + +so uh if B K plus 1 is in + + align:start position:0% +so uh if B K plus 1 is in + + + align:start position:0% +so uh if B K plus 1 is in +span of B1 up to V K + + align:start position:0% + + + + align:start position:0% + +then + + align:start position:0% +then + + + align:start position:0% +then +E1 up to e m of K + + align:start position:0% +E1 up to e m of K + + + align:start position:0% +E1 up to e m of K +I should say the span of these vectors + + align:start position:0% + + + + align:start position:0% + +equals + + align:start position:0% +equals + + + align:start position:0% +equals +span of V1 up to V + + align:start position:0% +span of V1 up to V + + + align:start position:0% +span of V1 up to V +k equals + + align:start position:0% +k equals + + + align:start position:0% +k equals +because V K plus 1 is in this span this + + align:start position:0% +because V K plus 1 is in this span this + + + align:start position:0% +because V K plus 1 is in this span this +span is also equal to + + align:start position:0% +span is also equal to + + + align:start position:0% +span is also equal to +the + + align:start position:0% +the + + + align:start position:0% +the +K plus 1. + + align:start position:0% +K plus 1. + + + align:start position:0% +K plus 1. +and therefore uh + + align:start position:0% + + + + align:start position:0% + +this case is handled and we're in this + + align:start position:0% +this case is handled and we're in this + + + align:start position:0% +this case is handled and we're in this +spot where we don't add anything to the + + align:start position:0% +spot where we don't add anything to the + + + align:start position:0% +spot where we don't add anything to the +previous uh collection okay + + align:start position:0% + + + + align:start position:0% + +this proves uh what we wanted to for n + + align:start position:0% +this proves uh what we wanted to for n + + + align:start position:0% +this proves uh what we wanted to for n +equals K plus one + + align:start position:0% +equals K plus one + + + align:start position:0% +equals K plus one +um + + align:start position:0% +um + + + align:start position:0% +um +by not adding anything so this was in + + align:start position:0% +by not adding anything so this was in + + + align:start position:0% +by not adding anything so this was in +the case that VK plus one is in the span + + align:start position:0% +the case that VK plus one is in the span + + + align:start position:0% +the case that VK plus one is in the span +of V1 up to VK so now let's do the more + + align:start position:0% +of V1 up to VK so now let's do the more + + + align:start position:0% +of V1 up to VK so now let's do the more +interesting case of V1 not equal or not + + align:start position:0% +interesting case of V1 not equal or not + + + align:start position:0% +interesting case of V1 not equal or not +in the span of V1 up to VK + + align:start position:0% +in the span of V1 up to VK + + + align:start position:0% +in the span of V1 up to VK +so now suppose + + align:start position:0% +so now suppose + + + align:start position:0% +so now suppose +be K plus one + + align:start position:0% +be K plus one + + + align:start position:0% +be K plus one +is not in + + align:start position:0% +is not in + + + align:start position:0% +is not in +um + + align:start position:0% + + + + align:start position:0% + +span of V1 to VK + + align:start position:0% + + + + align:start position:0% + +I Define + + align:start position:0% + + + + align:start position:0% + +w k Plus 1. + + align:start position:0% + + + + align:start position:0% + +to be V A plus 1 minus its projection + + align:start position:0% +to be V A plus 1 minus its projection + + + align:start position:0% +to be V A plus 1 minus its projection +onto the previous uh list of orthonormal + + align:start position:0% +onto the previous uh list of orthonormal + + + align:start position:0% +onto the previous uh list of orthonormal +vectors so some from J equals one + + align:start position:0% +vectors so some from J equals one + + + align:start position:0% +vectors so some from J equals one +M of K + + align:start position:0% +M of K + + + align:start position:0% +M of K +B K plus 1. + + align:start position:0% +B K plus 1. + + + align:start position:0% +B K plus 1. +e j + + align:start position:0% + + + + align:start position:0% + +then + + align:start position:0% +then + + + align:start position:0% +then +first note that + + align:start position:0% +first note that + + + align:start position:0% +first note that +this Vector cannot be so w k plus 1 this + + align:start position:0% +this Vector cannot be so w k plus 1 this + + + align:start position:0% +this Vector cannot be so w k plus 1 this +this Vector cannot be zero right + + align:start position:0% +this Vector cannot be zero right + + + align:start position:0% +this Vector cannot be zero right +otherwise this would imply that V K plus + + align:start position:0% +otherwise this would imply that V K plus + + + align:start position:0% +otherwise this would imply that V K plus +1 is equal to this quantity here and + + align:start position:0% +1 is equal to this quantity here and + + + align:start position:0% +1 is equal to this quantity here and +therefore since uh and therefore V K + + align:start position:0% +therefore since uh and therefore V K + + + align:start position:0% +therefore since uh and therefore V K +plus 1 is in the span of the ejs for J + + align:start position:0% +plus 1 is in the span of the ejs for J + + + align:start position:0% +plus 1 is in the span of the ejs for J +between one of between 1 and M sub K + + align:start position:0% +between one of between 1 and M sub K + + + align:start position:0% +between one of between 1 and M sub K +which is equal to the span of the V J is + + align:start position:0% +which is equal to the span of the V J is + + + align:start position:0% +which is equal to the span of the V J is +for one up to K so but we're assuming + + align:start position:0% +for one up to K so but we're assuming + + + align:start position:0% +for one up to K so but we're assuming +this is not in the span + + align:start position:0% + + + + align:start position:0% + +of + + align:start position:0% +of + + + align:start position:0% +of +should say this is equal to the span of + + align:start position:0% +should say this is equal to the span of + + + align:start position:0% +should say this is equal to the span of +E1 up to a m sub K right that's what + + align:start position:0% +E1 up to a m sub K right that's what + + + align:start position:0% +E1 up to a m sub K right that's what +we're assuming that's the inductive + + align:start position:0% +we're assuming that's the inductive + + + align:start position:0% +we're assuming that's the inductive +hypothesis right + + align:start position:0% +hypothesis right + + + align:start position:0% +hypothesis right +so then + + align:start position:0% + + + + align:start position:0% + +this uh + + align:start position:0% +this uh + + + align:start position:0% +this uh +Vector does not equal zero + + align:start position:0% + + + + align:start position:0% + +and Define e + + align:start position:0% +and Define e + + + align:start position:0% +and Define e +M sub K plus 1 or M to be the vector + + align:start position:0% +M sub K plus 1 or M to be the vector + + + align:start position:0% +M sub K plus 1 or M to be the vector +WK over its length for plus one + + align:start position:0% + + + + align:start position:0% + +now this is a unit vector + + align:start position:0% +now this is a unit vector + + + align:start position:0% +now this is a unit vector +um and + + align:start position:0% + + + + align:start position:0% + +and what and + + align:start position:0% +and what and + + + align:start position:0% +and what and +um + + align:start position:0% + + + + align:start position:0% + +and if I take so now I claim this is + + align:start position:0% +and if I take so now I claim this is + + + align:start position:0% +and if I take so now I claim this is +orthogonal to E1 up to e of M sub k + + align:start position:0% +orthogonal to E1 up to e of M sub k + + + align:start position:0% +orthogonal to E1 up to e of M sub k +if I take e + + align:start position:0% +if I take e + + + align:start position:0% +if I take e +M K plus 1 and a product e sub N Sub J + + align:start position:0% +M K plus 1 and a product e sub N Sub J + + + align:start position:0% +M K plus 1 and a product e sub N Sub J +so let's take + + align:start position:0% + + + + align:start position:0% + +this is equal to Simply by definition 1 + + align:start position:0% +this is equal to Simply by definition 1 + + + align:start position:0% +this is equal to Simply by definition 1 +over + + align:start position:0% +over + + + align:start position:0% +over +length of M K plus 1 times the inner + + align:start position:0% +length of M K plus 1 times the inner + + + align:start position:0% +length of M K plus 1 times the inner +product of V K plus one minus + + align:start position:0% +product of V K plus one minus + + + align:start position:0% +product of V K plus one minus +sum from J equals one to M sub K so + + align:start position:0% +sum from J equals one to M sub K so + + + align:start position:0% +sum from J equals one to M sub K so +remember this this is supposed to be the + + align:start position:0% +remember this this is supposed to be the + + + align:start position:0% +remember this this is supposed to be the +projection onto the E1 up to e m sub K + + align:start position:0% +projection onto the E1 up to e m sub K + + + align:start position:0% +projection onto the E1 up to e m sub K +and V K plus 1 minus that is supposed to + + align:start position:0% +and V K plus 1 minus that is supposed to + + + align:start position:0% +and V K plus 1 minus that is supposed to +be orthogonal to those guys so we'll see + + align:start position:0% +be orthogonal to those guys so we'll see + + + align:start position:0% +be orthogonal to those guys so we'll see +that this ends up being zero + + align:start position:0% + + + + align:start position:0% + +and let me + + align:start position:0% +and let me + + + align:start position:0% +and let me +change this J to an L since I am + + align:start position:0% + + + + align:start position:0% + +or no + + align:start position:0% + + + + align:start position:0% + +and I get + + align:start position:0% +and I get + + + align:start position:0% +and I get +one over + + align:start position:0% + + + + align:start position:0% + +times the sum uh + + align:start position:0% +times the sum uh + + + align:start position:0% +times the sum uh +or times + + align:start position:0% +or times + + + align:start position:0% +or times +V A plus one + + align:start position:0% +V A plus one + + + align:start position:0% +V A plus one +Isabel + + align:start position:0% +Isabel + + + align:start position:0% +Isabel +minus now Isabel inner product with + + align:start position:0% + + + + align:start position:0% + +the sum right now this is the sum from J + + align:start position:0% +the sum right now this is the sum from J + + + align:start position:0% +the sum right now this is the sum from J +equals 1 to M sub K of this number here + + align:start position:0% +equals 1 to M sub K of this number here + + + align:start position:0% +equals 1 to M sub K of this number here +times the inner product of e sub J inner + + align:start position:0% +times the inner product of e sub J inner + + + align:start position:0% +times the inner product of e sub J inner +product e sub l + + align:start position:0% +product e sub l + + + align:start position:0% +product e sub l +right + + align:start position:0% +right + + + align:start position:0% +right +um now the inner product of e sub J and + + align:start position:0% +um now the inner product of e sub J and + + + align:start position:0% +um now the inner product of e sub J and +E sub L is zero unless J equals L and + + align:start position:0% +E sub L is zero unless J equals L and + + + align:start position:0% +E sub L is zero unless J equals L and +one other and one if J equals l and so I + + align:start position:0% +one other and one if J equals l and so I + + + align:start position:0% +one other and one if J equals l and so I +only pick up + + align:start position:0% +only pick up + + + align:start position:0% +only pick up +uh the J equals L part of this sum when + + align:start position:0% +uh the J equals L part of this sum when + + + align:start position:0% +uh the J equals L part of this sum when +this inner product hits e sub l + + align:start position:0% +this inner product hits e sub l + + + align:start position:0% +this inner product hits e sub l +uh in particular I only pick up the + + align:start position:0% +uh in particular I only pick up the + + + align:start position:0% +uh in particular I only pick up the +coefficient in front since these have + + align:start position:0% +coefficient in front since these have + + + align:start position:0% +coefficient in front since these have +unit length so I get V sub + + align:start position:0% +unit length so I get V sub + + + align:start position:0% +unit length so I get V sub +Plus One V sub l + + align:start position:0% +Plus One V sub l + + + align:start position:0% +Plus One V sub l +equals zero + + align:start position:0% + + + + align:start position:0% + +then + + align:start position:0% +then + + + align:start position:0% +then +um + + align:start position:0% + + + + align:start position:0% + +this guy + + align:start position:0% +this guy + + + align:start position:0% +this guy +now does + + align:start position:0% + + + + align:start position:0% + +in the job so I would write a little bit + + align:start position:0% +in the job so I would write a little bit + + + align:start position:0% +in the job so I would write a little bit +more but I'm running short on time + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +um so we've proved the claim + + align:start position:0% +um so we've proved the claim + + + align:start position:0% +um so we've proved the claim +and + + align:start position:0% + + + + align:start position:0% + +now let's use this to conclude + + align:start position:0% +now let's use this to conclude + + + align:start position:0% +now let's use this to conclude +that + + align:start position:0% +that + + + align:start position:0% +that +this collection of all of these Els + + align:start position:0% + + + + align:start position:0% + +um are maximal + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% + + + + align:start position:0% + +so we let + + align:start position:0% + + + + align:start position:0% + +s to be + + align:start position:0% +s to be + + + align:start position:0% +s to be +uh + + align:start position:0% + + + + align:start position:0% + +V sub n + + align:start position:0% +V sub n + + + align:start position:0% +V sub n +which equals + + align:start position:0% + + + + align:start position:0% + +and s is + + align:start position:0% + + + + align:start position:0% + +an orthonormal subset of h + + align:start position:0% + + + + align:start position:0% + +So eventually so you know I may not be + + align:start position:0% +So eventually so you know I may not be + + + align:start position:0% +So eventually so you know I may not be +adding any more vectors after a certain + + align:start position:0% +adding any more vectors after a certain + + + align:start position:0% +adding any more vectors after a certain +point + + align:start position:0% +point + + + align:start position:0% +point +and therefore just have a finite + + align:start position:0% +and therefore just have a finite + + + align:start position:0% +and therefore just have a finite +collection that's also + + align:start position:0% +collection that's also + + + align:start position:0% +collection that's also +possible but I may also have a + + align:start position:0% +possible but I may also have a + + + align:start position:0% +possible but I may also have a +accountably infinite collection + + align:start position:0% + + + + align:start position:0% + +so this is a orthonormal set by + + align:start position:0% +so this is a orthonormal set by + + + align:start position:0% +so this is a orthonormal set by +B + + align:start position:0% +B + + + align:start position:0% +B +and so + + align:start position:0% +and so + + + align:start position:0% +and so +uh + + align:start position:0% +uh + + + align:start position:0% +uh +we now show + + align:start position:0% + + + + align:start position:0% + +X is maximum + + align:start position:0% +X is maximum + + + align:start position:0% +X is maximum +okay + + align:start position:0% + + + + align:start position:0% + +all right here is where so we haven't + + align:start position:0% +all right here is where so we haven't + + + align:start position:0% +all right here is where so we haven't +used anything about the nature of this + + align:start position:0% +used anything about the nature of this + + + align:start position:0% +used anything about the nature of this +subset of H all we've used is that you + + align:start position:0% +subset of H all we've used is that you + + + align:start position:0% +subset of H all we've used is that you +know it's accountable so we could do + + align:start position:0% +know it's accountable so we could do + + + align:start position:0% +know it's accountable so we could do +this step by step where we construct + + align:start position:0% +this step by step where we construct + + + align:start position:0% +this step by step where we construct +these orthonormal vectors that span each + + align:start position:0% +these orthonormal vectors that span each + + + align:start position:0% +these orthonormal vectors that span each +finite uh + + align:start position:0% +finite uh + + + align:start position:0% +finite uh +equal to the span of each finite + + align:start position:0% +equal to the span of each finite + + + align:start position:0% +equal to the span of each finite +collection of vectors now to show its + + align:start position:0% +collection of vectors now to show its + + + align:start position:0% +collection of vectors now to show its +maximal this is where we use the fact + + align:start position:0% +maximal this is where we use the fact + + + align:start position:0% +maximal this is where we use the fact +that this collection of these were dense + + align:start position:0% +that this collection of these were dense + + + align:start position:0% +that this collection of these were dense +there are dense in h so + + align:start position:0% +there are dense in h so + + + align:start position:0% +there are dense in h so +um + + align:start position:0% + + + + align:start position:0% + +suppose U is an H + + align:start position:0% +suppose U is an H + + + align:start position:0% +suppose U is an H +and + + align:start position:0% +and + + + align:start position:0% +and +um + + align:start position:0% +um + + + align:start position:0% +um +for all l + + align:start position:0% +for all l + + + align:start position:0% +for all l +U of e sub l + + align:start position:0% +U of e sub l + + + align:start position:0% +U of e sub l +equals zero so this is either a finite + + align:start position:0% +equals zero so this is either a finite + + + align:start position:0% +equals zero so this is either a finite +set so L is between 1 and N or it's a + + align:start position:0% +set so L is between 1 and N or it's a + + + align:start position:0% +set so L is between 1 and N or it's a +countable set and L is going from 1 to + + align:start position:0% +countable set and L is going from 1 to + + + align:start position:0% +countable set and L is going from 1 to +Infinity so this equals it + + align:start position:0% +Infinity so this equals it + + + align:start position:0% +Infinity so this equals it +either this is equal to E + + align:start position:0% +either this is equal to E + + + align:start position:0% +either this is equal to E +1 up to E + + align:start position:0% +1 up to E + + + align:start position:0% +1 up to E +M sub n for some n or + + align:start position:0% + + + + align:start position:0% + +B1 + + align:start position:0% +B1 + + + align:start position:0% +B1 +is countably infinite okay + + align:start position:0% + + + + align:start position:0% + +so since + + align:start position:0% + + + + align:start position:0% + +v j + + align:start position:0% +v j + + + align:start position:0% +v j +this is a dense + + align:start position:0% + + + + align:start position:0% + +subset of H + + align:start position:0% + + + + align:start position:0% + +we can find a sequence + + align:start position:0% + + + + align:start position:0% + +of elements from this collection so V of + + align:start position:0% +of elements from this collection so V of + + + align:start position:0% +of elements from this collection so V of +J sub k + + align:start position:0% +J sub k + + + align:start position:0% +J sub k +equals 1 to Infinity + + align:start position:0% + + + + align:start position:0% + +such that + + align:start position:0% +such that + + + align:start position:0% +such that +v j of K converges to U + + align:start position:0% +v j of K converges to U + + + align:start position:0% +v j of K converges to U +as + + align:start position:0% +as + + + align:start position:0% +as +K goes to Infinity + + align:start position:0% + + + + align:start position:0% + +okay now + + align:start position:0% + + + + align:start position:0% + +by property a + + align:start position:0% +by property a + + + align:start position:0% +by property a +the fact that this span is equal to that + + align:start position:0% +the fact that this span is equal to that + + + align:start position:0% +the fact that this span is equal to that +span + + align:start position:0% + + + + align:start position:0% + +V of J sub K is in + + align:start position:0% +V of J sub K is in + + + align:start position:0% +V of J sub K is in +span of E1 up to E + + align:start position:0% +span of E1 up to E + + + align:start position:0% +span of E1 up to E +M of + + align:start position:0% +M of + + + align:start position:0% +M of +J sub k + + align:start position:0% + + + + align:start position:0% + +and therefore + + align:start position:0% +and therefore + + + align:start position:0% +and therefore +my vessels inequality + + align:start position:0% +my vessels inequality + + + align:start position:0% +my vessels inequality +and the fact that U is orthogonal to all + + align:start position:0% +and the fact that U is orthogonal to all + + + align:start position:0% +and the fact that U is orthogonal to all +of these uh uh orthonormal vectors + + align:start position:0% + + + + align:start position:0% + +I get that + + align:start position:0% +I get that + + + align:start position:0% +I get that +V of + + align:start position:0% +V of + + + align:start position:0% +V of +J + + align:start position:0% +J + + + align:start position:0% +J +k + + align:start position:0% +k + + + align:start position:0% +k +squared + + align:start position:0% +squared + + + align:start position:0% +squared +now V of J sub of J of K this is in this + + align:start position:0% +now V of J sub of J of K this is in this + + + align:start position:0% +now V of J sub of J of K this is in this +span so you can show that in fact + + align:start position:0% +span so you can show that in fact + + + align:start position:0% +span so you can show that in fact +um + + align:start position:0% + + + + align:start position:0% + +this + + align:start position:0% +this + + + align:start position:0% +this +Norm is in fact equal + + align:start position:0% + + + + align:start position:0% + +to the sum of the coefficients that I + + align:start position:0% +to the sum of the coefficients that I + + + align:start position:0% +to the sum of the coefficients that I +get from taking the inner product of + + align:start position:0% + + + + align:start position:0% + +okay if I have a vector in the span of a + + align:start position:0% +okay if I have a vector in the span of a + + + align:start position:0% +okay if I have a vector in the span of a +collection of orthonormal vectors a + + align:start position:0% +collection of orthonormal vectors a + + + align:start position:0% +collection of orthonormal vectors a +finite collection of orthonormal vectors + + align:start position:0% +finite collection of orthonormal vectors + + + align:start position:0% +finite collection of orthonormal vectors +then the norm squared is equal to the + + align:start position:0% +then the norm squared is equal to the + + + align:start position:0% +then the norm squared is equal to the +sum of the coefficients just like an RN + + align:start position:0% +sum of the coefficients just like an RN + + + align:start position:0% +sum of the coefficients just like an RN +and Since U is orthogonal to each of + + align:start position:0% +and Since U is orthogonal to each of + + + align:start position:0% +and Since U is orthogonal to each of +these + + align:start position:0% + + + + align:start position:0% + +this I can write as + + align:start position:0% + + + + align:start position:0% + +and by vessels inequality this is less + + align:start position:0% +and by vessels inequality this is less + + + align:start position:0% +and by vessels inequality this is less +than or equal to + + align:start position:0% +than or equal to + + + align:start position:0% +than or equal to +um + + align:start position:0% + + + + align:start position:0% + +the sum of these things squared is less + + align:start position:0% +the sum of these things squared is less + + + align:start position:0% +the sum of these things squared is less +than or equal to + + align:start position:0% + + + + align:start position:0% + +squared and this goes to zero + + align:start position:0% +squared and this goes to zero + + + align:start position:0% +squared and this goes to zero +because K goes to Infinity since the V + + align:start position:0% +because K goes to Infinity since the V + + + align:start position:0% +because K goes to Infinity since the V +of J sub K is converge to U but we + + align:start position:0% +of J sub K is converge to U but we + + + align:start position:0% +of J sub K is converge to U but we +started off with the norm of V of J sub + + align:start position:0% +started off with the norm of V of J sub + + + align:start position:0% +started off with the norm of V of J sub +K which implies + + align:start position:0% + + + + align:start position:0% + +0 and therefore + + align:start position:0% +0 and therefore + + + align:start position:0% +0 and therefore +U which is the limit of these must be + + align:start position:0% +U which is the limit of these must be + + + align:start position:0% +U which is the limit of these must be +zero proving that this is a maximum + + align:start position:0% +zero proving that this is a maximum + + + align:start position:0% +zero proving that this is a maximum +subset + + align:start position:0% +subset + + + align:start position:0% +subset +okay + + align:start position:0% +okay + + + align:start position:0% +okay +um + + align:start position:0% +um + + + align:start position:0% +um +all right so next time we'll prove that + + align:start position:0% +all right so next time we'll prove that + + + align:start position:0% +all right so next time we'll prove that +these maximal orthonormal countable + + align:start position:0% +these maximal orthonormal countable + + + align:start position:0% +these maximal orthonormal countable +count of these + + align:start position:0% +count of these + + + align:start position:0% +count of these +maximal countable orthonormal subsets in + + align:start position:0% +maximal countable orthonormal subsets in + + + align:start position:0% +maximal countable orthonormal subsets in +fact form a pretty good analog of uh + + align:start position:0% +fact form a pretty good analog of uh + + + align:start position:0% +fact form a pretty good analog of uh +bases that you find in finite + + align:start position:0% +bases that you find in finite + + + align:start position:0% +bases that you find in finite +dimensional linear algebra + + align:start position:0% +dimensional linear algebra + + + align:start position:0% +dimensional linear algebra +we'll stop there \ No newline at end of file diff --git a/EmeWBxXlzKA.txt b/EmeWBxXlzKA.txt new file mode 100644 index 0000000000000000000000000000000000000000..2175d83b8f58d2dd17ce53df1109b3da44d4bfed --- /dev/null +++ b/EmeWBxXlzKA.txt @@ -0,0 +1,1219 @@ +align:start position:0% + +let's talk about the more circle an + + align:start position:0% +let's talk about the more circle an + + + align:start position:0% +let's talk about the more circle an +important tool in material science and + + align:start position:0% +important tool in material science and + + + align:start position:0% +important tool in material science and +mechanical engineering + + align:start position:0% +mechanical engineering + + + align:start position:0% +mechanical engineering +what is more circle and what does it do + + align:start position:0% +what is more circle and what does it do + + + align:start position:0% +what is more circle and what does it do +assume we have a rod and you want to + + align:start position:0% +assume we have a rod and you want to + + + align:start position:0% +assume we have a rod and you want to +break it with your hands what can you do + + align:start position:0% +break it with your hands what can you do + + + align:start position:0% +break it with your hands what can you do +about it you can pull it compress it or + + align:start position:0% +about it you can pull it compress it or + + + align:start position:0% +about it you can pull it compress it or +twist it each of these will induce a + + align:start position:0% +twist it each of these will induce a + + + align:start position:0% +twist it each of these will induce a +stress in the rod in a different way and + + align:start position:0% +stress in the rod in a different way and + + + align:start position:0% +stress in the rod in a different way and +the Mohr circle helps you analyze this + + align:start position:0% +the Mohr circle helps you analyze this + + + align:start position:0% +the Mohr circle helps you analyze this +Mohr circle is a graphical tool a visual + + align:start position:0% +Mohr circle is a graphical tool a visual + + + align:start position:0% +Mohr circle is a graphical tool a visual +way to see how to go from one state of + + align:start position:0% +way to see how to go from one state of + + + align:start position:0% +way to see how to go from one state of +stress to another usually you're given a + + align:start position:0% +stress to another usually you're given a + + + align:start position:0% +stress to another usually you're given a +state of stress that you calculated from + + align:start position:0% +state of stress that you calculated from + + + align:start position:0% +state of stress that you calculated from +using stress equations then you want to + + align:start position:0% +using stress equations then you want to + + + align:start position:0% +using stress equations then you want to +find a state of stress at a new angle of + + align:start position:0% +find a state of stress at a new angle of + + + align:start position:0% +find a state of stress at a new angle of +orientation or principal stresses at + + align:start position:0% +orientation or principal stresses at + + + align:start position:0% +orientation or principal stresses at +that orientation or the maximum in plane + + align:start position:0% +that orientation or the maximum in plane + + + align:start position:0% +that orientation or the maximum in plane +shear stresses and Mohr circle allows + + align:start position:0% +shear stresses and Mohr circle allows + + + align:start position:0% +shear stresses and Mohr circle allows +you to draw this representative element + + align:start position:0% +you to draw this representative element + + + align:start position:0% +you to draw this representative element +to visualize the calculations for you + + align:start position:0% + + + + align:start position:0% + +now let's derive the Mohr circle so now + + align:start position:0% +now let's derive the Mohr circle so now + + + align:start position:0% +now let's derive the Mohr circle so now +we take a look at the piece of material + + align:start position:0% +we take a look at the piece of material + + + align:start position:0% +we take a look at the piece of material +that we cut from the rod that we're + + align:start position:0% +that we cut from the rod that we're + + + align:start position:0% +that we cut from the rod that we're +trying to break and originally we had + + align:start position:0% +trying to break and originally we had + + + align:start position:0% +trying to break and originally we had +this coordinate system and we have some + + align:start position:0% +this coordinate system and we have some + + + align:start position:0% +this coordinate system and we have some +stresses where the Sigma is represented + + align:start position:0% +stresses where the Sigma is represented + + + align:start position:0% +stresses where the Sigma is represented +normal stress and the towels represent + + align:start position:0% +normal stress and the towels represent + + + align:start position:0% +normal stress and the towels represent +the shear stress so we draw this + + align:start position:0% +the shear stress so we draw this + + + align:start position:0% +the shear stress so we draw this +representative pair of stresses for + + align:start position:0% +representative pair of stresses for + + + align:start position:0% +representative pair of stresses for +convenience + + align:start position:0% + + + + align:start position:0% + +and then we want to analyze those + + align:start position:0% +and then we want to analyze those + + + align:start position:0% +and then we want to analyze those +stresses on this cross-section area so + + align:start position:0% +stresses on this cross-section area so + + + align:start position:0% +stresses on this cross-section area so +we do is we need to rotate the + + align:start position:0% +we do is we need to rotate the + + + align:start position:0% +we do is we need to rotate the +coordinate system so that the x-axis + + align:start position:0% +coordinate system so that the x-axis + + + align:start position:0% +coordinate system so that the x-axis +would line up with the unit normal + + align:start position:0% +would line up with the unit normal + + + align:start position:0% +would line up with the unit normal +vector to this cross sectional area and + + align:start position:0% +vector to this cross sectional area and + + + align:start position:0% +vector to this cross sectional area and +then the y axis would be rotated to this + + align:start position:0% +then the y axis would be rotated to this + + + align:start position:0% +then the y axis would be rotated to this +direction and would be lined up with and + + align:start position:0% +direction and would be lined up with and + + + align:start position:0% +direction and would be lined up with and +primed unit vector is shown here so this + + align:start position:0% +primed unit vector is shown here so this + + + align:start position:0% +primed unit vector is shown here so this +is done by rotating this coordinate + + align:start position:0% +is done by rotating this coordinate + + + align:start position:0% +is done by rotating this coordinate +system by an angle theta + + align:start position:0% +system by an angle theta + + + align:start position:0% +system by an angle theta +counterclockwise then we can obtain the + + align:start position:0% +counterclockwise then we can obtain the + + + align:start position:0% +counterclockwise then we can obtain the +unit normal vector in matrix form and + + align:start position:0% +unit normal vector in matrix form and + + + align:start position:0% +unit normal vector in matrix form and +that is just cosine theta and sine theta + + align:start position:0% +that is just cosine theta and sine theta + + + align:start position:0% +that is just cosine theta and sine theta +and similarly the N prime vector that's + + align:start position:0% +and similarly the N prime vector that's + + + align:start position:0% +and similarly the N prime vector that's +just negative sine theta and cosine + + align:start position:0% +just negative sine theta and cosine + + + align:start position:0% +just negative sine theta and cosine +theta so we can now get the stress + + align:start position:0% +theta so we can now get the stress + + + align:start position:0% +theta so we can now get the stress +tensor by taking the dot product of the + + align:start position:0% +tensor by taking the dot product of the + + + align:start position:0% +tensor by taking the dot product of the +stresses in the x-direction with the + + align:start position:0% +stresses in the x-direction with the + + + align:start position:0% +stresses in the x-direction with the +unit normal vector and the dot + + align:start position:0% +unit normal vector and the dot + + + align:start position:0% +unit normal vector and the dot +properties stresses in the y-direction + + align:start position:0% +properties stresses in the y-direction + + + align:start position:0% +properties stresses in the y-direction +with the unit normal vector so now we + + align:start position:0% +with the unit normal vector so now we + + + align:start position:0% +with the unit normal vector so now we +can write out the normal stress in the + + align:start position:0% +can write out the normal stress in the + + + align:start position:0% +can write out the normal stress in the +new coordinate system by just taking the + + align:start position:0% +new coordinate system by just taking the + + + align:start position:0% +new coordinate system by just taking the +dot product of the stress tensor with + + align:start position:0% +dot product of the stress tensor with + + + align:start position:0% +dot product of the stress tensor with +the unit normal vector and similarly we + + align:start position:0% +the unit normal vector and similarly we + + + align:start position:0% +the unit normal vector and similarly we +can find the shear stress in the new + + align:start position:0% +can find the shear stress in the new + + + align:start position:0% +can find the shear stress in the new +coordinate system by taking the dot + + align:start position:0% +coordinate system by taking the dot + + + align:start position:0% +coordinate system by taking the dot +product of the stress tensor with the M + + align:start position:0% +product of the stress tensor with the M + + + align:start position:0% +product of the stress tensor with the M +Prime and we can do these complicated + + align:start position:0% +Prime and we can do these complicated + + + align:start position:0% +Prime and we can do these complicated +calculations on Mathematica which I will + + align:start position:0% +calculations on Mathematica which I will + + + align:start position:0% +calculations on Mathematica which I will +show you right now so I've already typed + + align:start position:0% +show you right now so I've already typed + + + align:start position:0% +show you right now so I've already typed +in these vectors into Mathematica and n + + align:start position:0% +in these vectors into Mathematica and n + + + align:start position:0% +in these vectors into Mathematica and n +represents the unit normal vector and NP + + align:start position:0% +represents the unit normal vector and NP + + + align:start position:0% +represents the unit normal vector and NP +is just n prime and T is the stress + + align:start position:0% +is just n prime and T is the stress + + + align:start position:0% +is just n prime and T is the stress +tensor + + align:start position:0% +tensor + + + align:start position:0% +tensor +so we want to find the normal stress in + + align:start position:0% +so we want to find the normal stress in + + + align:start position:0% +so we want to find the normal stress in +the new coordinate system Sigma prime + + align:start position:0% +the new coordinate system Sigma prime + + + align:start position:0% +the new coordinate system Sigma prime +and that is just dotting T with N and we + + align:start position:0% +and that is just dotting T with N and we + + + align:start position:0% +and that is just dotting T with N and we +get this simplified version that so + + align:start position:0% +get this simplified version that so + + + align:start position:0% +get this simplified version that so +that's our signal Prime then we want to + + align:start position:0% +that's our signal Prime then we want to + + + align:start position:0% +that's our signal Prime then we want to +find our tau prime and that is just T + + align:start position:0% +find our tau prime and that is just T + + + align:start position:0% +find our tau prime and that is just T +dotted with NP again we want to find a + + align:start position:0% +dotted with NP again we want to find a + + + align:start position:0% +dotted with NP again we want to find a +simplified version so that's that and + + align:start position:0% +simplified version so that's that and + + + align:start position:0% +simplified version so that's that and +don't worry about this theta Xin to + + align:start position:0% +don't worry about this theta Xin to + + + align:start position:0% +don't worry about this theta Xin to +Thetas we'll use trig identities to + + align:start position:0% +Thetas we'll use trig identities to + + + align:start position:0% +Thetas we'll use trig identities to +change them so here's our trig + + align:start position:0% +change them so here's our trig + + + align:start position:0% +change them so here's our trig +identities and we just plug them back in + + align:start position:0% +identities and we just plug them back in + + + align:start position:0% +identities and we just plug them back in +and we obtain these two equations for + + align:start position:0% +and we obtain these two equations for + + + align:start position:0% +and we obtain these two equations for +our new stresses then we move all the + + align:start position:0% +our new stresses then we move all the + + + align:start position:0% +our new stresses then we move all the +terms containing two theta to the right + + align:start position:0% +terms containing two theta to the right + + + align:start position:0% +terms containing two theta to the right +side of the equations and all the rest + + align:start position:0% +side of the equations and all the rest + + + align:start position:0% +side of the equations and all the rest +of the terms the left side of equations + + align:start position:0% +of the terms the left side of equations + + + align:start position:0% +of the terms the left side of equations +and we square both sides of the + + align:start position:0% +and we square both sides of the + + + align:start position:0% +and we square both sides of the +equations to get equation one and + + align:start position:0% +equations to get equation one and + + + align:start position:0% +equations to get equation one and +equation two as shown here we add + + align:start position:0% +equation two as shown here we add + + + align:start position:0% +equation two as shown here we add +equation one and equation two and some + + align:start position:0% +equation one and equation two and some + + + align:start position:0% +equation one and equation two and some +terms cancel finally we get this really + + align:start position:0% +terms cancel finally we get this really + + + align:start position:0% +terms cancel finally we get this really +creamy equation shown here now look + + align:start position:0% +creamy equation shown here now look + + + align:start position:0% +creamy equation shown here now look +closely to this equation what form of + + align:start position:0% +closely to this equation what form of + + + align:start position:0% +closely to this equation what form of +equation does it look like + + align:start position:0% +equation does it look like + + + align:start position:0% +equation does it look like +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +you might have guessed that it looks + + align:start position:0% +you might have guessed that it looks + + + align:start position:0% +you might have guessed that it looks +like the equation of a circle and you're + + align:start position:0% +like the equation of a circle and you're + + + align:start position:0% +like the equation of a circle and you're +absolutely right this is exactly how + + align:start position:0% +absolutely right this is exactly how + + + align:start position:0% +absolutely right this is exactly how +more circle is derived we can compare + + align:start position:0% +more circle is derived we can compare + + + align:start position:0% +more circle is derived we can compare +the equation with the equation of a + + align:start position:0% +the equation with the equation of a + + + align:start position:0% +the equation with the equation of a +circle and we see that more circle is + + align:start position:0% +circle and we see that more circle is + + + align:start position:0% +circle and we see that more circle is +centered at the coordinates Sigma X plus + + align:start position:0% +centered at the coordinates Sigma X plus + + + align:start position:0% +centered at the coordinates Sigma X plus +Sigma Y over to 0 and Sigma X plus Sigma + + align:start position:0% +Sigma Y over to 0 and Sigma X plus Sigma + + + align:start position:0% +Sigma Y over to 0 and Sigma X plus Sigma +Y over 2 is the average normal stress in + + align:start position:0% +Y over 2 is the average normal stress in + + + align:start position:0% +Y over 2 is the average normal stress in +the old coordinate system we can also + + align:start position:0% +the old coordinate system we can also + + + align:start position:0% +the old coordinate system we can also +obtain the radius of more circle + + align:start position:0% + + + + align:start position:0% + +now let me draw this more circle for you + + align:start position:0% +now let me draw this more circle for you + + + align:start position:0% +now let me draw this more circle for you +so we go back to our old coordinate + + align:start position:0% +so we go back to our old coordinate + + + align:start position:0% +so we go back to our old coordinate +system with some calculated stresses and + + align:start position:0% +system with some calculated stresses and + + + align:start position:0% +system with some calculated stresses and +then we need to construct this new + + align:start position:0% +then we need to construct this new + + + align:start position:0% +then we need to construct this new +coordinate system to draw this Mohr + + align:start position:0% +coordinate system to draw this Mohr + + + align:start position:0% +coordinate system to draw this Mohr +circle on I take the positive + + align:start position:0% +circle on I take the positive + + + align:start position:0% +circle on I take the positive +x-direction that's the plus sigma and + + align:start position:0% +x-direction that's the plus sigma and + + + align:start position:0% +x-direction that's the plus sigma and +the negative y-direction is plus tau + + align:start position:0% +the negative y-direction is plus tau + + + align:start position:0% +the negative y-direction is plus tau +just by convention then in order to draw + + align:start position:0% +just by convention then in order to draw + + + align:start position:0% +just by convention then in order to draw +the circle we take a pair of normal + + align:start position:0% +the circle we take a pair of normal + + + align:start position:0% +the circle we take a pair of normal +stress and shear stress and we plot + + align:start position:0% +stress and shear stress and we plot + + + align:start position:0% +stress and shear stress and we plot +their values as the coordinates in our + + align:start position:0% +their values as the coordinates in our + + + align:start position:0% +their values as the coordinates in our +coordinate system so we find a dot and + + align:start position:0% +coordinate system so we find a dot and + + + align:start position:0% +coordinate system so we find a dot and +is represented by Sigma X and tau XY + + align:start position:0% +is represented by Sigma X and tau XY + + + align:start position:0% +is represented by Sigma X and tau XY +then by our previous equations that we + + align:start position:0% +then by our previous equations that we + + + align:start position:0% +then by our previous equations that we +derived we can find the center of the + + align:start position:0% +derived we can find the center of the + + + align:start position:0% +derived we can find the center of the +circle which is located at Sigma average + + align:start position:0% +circle which is located at Sigma average + + + align:start position:0% +circle which is located at Sigma average +and 0 and Sigma average is just Sigma X + + align:start position:0% +and 0 and Sigma average is just Sigma X + + + align:start position:0% +and 0 and Sigma average is just Sigma X +plus Sigma Y over 2 then we find these + + align:start position:0% +plus Sigma Y over 2 then we find these + + + align:start position:0% +plus Sigma Y over 2 then we find these +values and we plot that on our Sigma + + align:start position:0% +values and we plot that on our Sigma + + + align:start position:0% +values and we plot that on our Sigma +axis + + align:start position:0% +axis + + + align:start position:0% +axis +that's just our center of the circle + + align:start position:0% +that's just our center of the circle + + + align:start position:0% +that's just our center of the circle +then we connect these two dots that we + + align:start position:0% +then we connect these two dots that we + + + align:start position:0% +then we connect these two dots that we +drew and that's just the radius of the + + align:start position:0% +drew and that's just the radius of the + + + align:start position:0% +drew and that's just the radius of the +circle now we can draw this circle since + + align:start position:0% +circle now we can draw this circle since + + + align:start position:0% +circle now we can draw this circle since +we know it's Center and a dot on its + + align:start position:0% +we know it's Center and a dot on its + + + align:start position:0% +we know it's Center and a dot on its +circumference we can now confirm the + + align:start position:0% +circumference we can now confirm the + + + align:start position:0% +circumference we can now confirm the +equation for the radius of the circle by + + align:start position:0% +equation for the radius of the circle by + + + align:start position:0% +equation for the radius of the circle by +doing some geometry here so this length + + align:start position:0% +doing some geometry here so this length + + + align:start position:0% +doing some geometry here so this length +is just Sigma average and then we have + + align:start position:0% +is just Sigma average and then we have + + + align:start position:0% +is just Sigma average and then we have +another length that's just Sigma X and + + align:start position:0% +another length that's just Sigma X and + + + align:start position:0% +another length that's just Sigma X and +the difference between these lengths is + + align:start position:0% +the difference between these lengths is + + + align:start position:0% +the difference between these lengths is +just Sigma X minus Sigma average then + + align:start position:0% +just Sigma X minus Sigma average then + + + align:start position:0% +just Sigma X minus Sigma average then +this length right here is simply tau XY + + align:start position:0% +this length right here is simply tau XY + + + align:start position:0% +this length right here is simply tau XY +and by looking at this right triangle + + align:start position:0% +and by looking at this right triangle + + + align:start position:0% +and by looking at this right triangle +and using pythagoras theorem we can + + align:start position:0% +and using pythagoras theorem we can + + + align:start position:0% +and using pythagoras theorem we can +obtain the radius of the circle which is + + align:start position:0% +obtain the radius of the circle which is + + + align:start position:0% +obtain the radius of the circle which is +written here under the square root it + + align:start position:0% +written here under the square root it + + + align:start position:0% +written here under the square root it +actually it confirms our original + + align:start position:0% +actually it confirms our original + + + align:start position:0% +actually it confirms our original +equation for obtaining the radius R of + + align:start position:0% +equation for obtaining the radius R of + + + align:start position:0% +equation for obtaining the radius R of +our circle so Mohr circle is very useful + + align:start position:0% +our circle so Mohr circle is very useful + + + align:start position:0% +our circle so Mohr circle is very useful +for visualizing the stresses on the + + align:start position:0% +for visualizing the stresses on the + + + align:start position:0% +for visualizing the stresses on the +material so we can just by doing simple + + align:start position:0% +material so we can just by doing simple + + + align:start position:0% +material so we can just by doing simple +geometry find the values for its + + align:start position:0% +geometry find the values for its + + + align:start position:0% +geometry find the values for its +principal stresses so in green you can + + align:start position:0% +principal stresses so in green you can + + + align:start position:0% +principal stresses so in green you can +see on the circle there's the maximum + + align:start position:0% +see on the circle there's the maximum + + + align:start position:0% +see on the circle there's the maximum +normal stress and minimum normal stress + + align:start position:0% +normal stress and minimum normal stress + + + align:start position:0% +normal stress and minimum normal stress +and now in red I'm labeling the minimum + + align:start position:0% +and now in red I'm labeling the minimum + + + align:start position:0% +and now in red I'm labeling the minimum +and maximum shear stresses \ No newline at end of file diff --git a/F7H6Ko0KL0Y.txt b/F7H6Ko0KL0Y.txt new file mode 100644 index 0000000000000000000000000000000000000000..260f1e11946d6923b3af679110929c84625ce001 --- /dev/null +++ b/F7H6Ko0KL0Y.txt @@ -0,0 +1,1832 @@ +align:start position:0% + +hi + + align:start position:0% +hi + + + align:start position:0% +hi +everyone okay so for the first H part of + + align:start position:0% +everyone okay so for the first H part of + + + align:start position:0% +everyone okay so for the first H part of +this + + align:start position:0% +this + + + align:start position:0% +this +course we've learned basically the ins + + align:start position:0% +course we've learned basically the ins + + + align:start position:0% +course we've learned basically the ins +and outs of of solving linear systems of + + align:start position:0% +and outs of of solving linear systems of + + + align:start position:0% +and outs of of solving linear systems of +equations + + align:start position:0% +equations + + + align:start position:0% +equations +um today we're going to do a little + + align:start position:0% +um today we're going to do a little + + + align:start position:0% +um today we're going to do a little +review of of the basic concepts um hope + + align:start position:0% +review of of the basic concepts um hope + + + align:start position:0% +review of of the basic concepts um hope +hopefully we'll we'll see um a few of + + align:start position:0% +hopefully we'll we'll see um a few of + + + align:start position:0% +hopefully we'll we'll see um a few of +them in the in the following problem + + align:start position:0% +them in the in the following problem + + + align:start position:0% +them in the in the following problem +we're given a square Matrix a a 3X3 + + align:start position:0% +we're given a square Matrix a a 3X3 + + + align:start position:0% +we're given a square Matrix a a 3X3 +Square Matrix a where the last entry is + + align:start position:0% +Square Matrix a where the last entry is + + + align:start position:0% +Square Matrix a where the last entry is +a parameter + + align:start position:0% +a parameter + + + align:start position:0% +a parameter +K and this parameter will vary and we'll + + align:start position:0% +K and this parameter will vary and we'll + + + align:start position:0% +K and this parameter will vary and we'll +see how the system um whe what happens + + align:start position:0% +see how the system um whe what happens + + + align:start position:0% +see how the system um whe what happens +to the system of equations ax equal to + + align:start position:0% +to the system of equations ax equal to + + + align:start position:0% +to the system of equations ax equal to +237 whether for which K has a unique + + align:start position:0% +237 whether for which K has a unique + + + align:start position:0% +237 whether for which K has a unique +solution for which Kate has infinitely + + align:start position:0% +solution for which Kate has infinitely + + + align:start position:0% +solution for which Kate has infinitely +many solutions then we'll find the lud + + align:start position:0% +many solutions then we'll find the lud + + + align:start position:0% +many solutions then we'll find the lud +DEC composition and finally we'll write + + align:start position:0% +DEC composition and finally we'll write + + + align:start position:0% +DEC composition and finally we'll write +down the complete solution to the system + + align:start position:0% +down the complete solution to the system + + + align:start position:0% +down the complete solution to the system +so I'll give you a few minutes to work + + align:start position:0% +so I'll give you a few minutes to work + + + align:start position:0% +so I'll give you a few minutes to work +this um problem on your own and then + + align:start position:0% +this um problem on your own and then + + + align:start position:0% +this um problem on your own and then +please come back and see how I do + + align:start position:0% + + + + align:start position:0% + +it all right welcome + + align:start position:0% +it all right welcome + + + align:start position:0% +it all right welcome +back so let's start with part a for + + align:start position:0% +back so let's start with part a for + + + align:start position:0% +back so let's start with part a for +which K does this system axal 237 have a + + align:start position:0% +which K does this system axal 237 have a + + + align:start position:0% +which K does this system axal 237 have a +unique + + align:start position:0% +unique + + + align:start position:0% +unique +solution so what do we know about um + + align:start position:0% +solution so what do we know about um + + + align:start position:0% +solution so what do we know about um +Square systems + + align:start position:0% +Square systems + + + align:start position:0% +Square systems +of square systems of linear + + align:start position:0% +of square systems of linear + + + align:start position:0% +of square systems of linear +equations um they have a unique solution + + align:start position:0% +equations um they have a unique solution + + + align:start position:0% +equations um they have a unique solution +when the Matrix a is invertible okay so + + align:start position:0% +when the Matrix a is invertible okay so + + + align:start position:0% +when the Matrix a is invertible okay so +now when is a invertible it is + + align:start position:0% +now when is a invertible it is + + + align:start position:0% +now when is a invertible it is +invertible when it is a full Rank and + + align:start position:0% +invertible when it is a full Rank and + + + align:start position:0% +invertible when it is a full Rank and +how do we figure this this out we do it + + align:start position:0% +how do we figure this this out we do it + + + align:start position:0% +how do we figure this this out we do it +by performing um row operations we do it + + align:start position:0% +by performing um row operations we do it + + + align:start position:0% +by performing um row operations we do it +by doing eliminations on The + + align:start position:0% +by doing eliminations on The + + + align:start position:0% +by doing eliminations on The +Matrix okay um but since we want to + + align:start position:0% +Matrix okay um but since we want to + + + align:start position:0% +Matrix okay um but since we want to +simulate an exam setting uh it always + + align:start position:0% +simulate an exam setting uh it always + + + align:start position:0% +simulate an exam setting uh it always +pays off to see what um tasks lie ahead + + align:start position:0% +pays off to see what um tasks lie ahead + + + align:start position:0% +pays off to see what um tasks lie ahead +of us so in in part C we'll um we're + + align:start position:0% +of us so in in part C we'll um we're + + + align:start position:0% +of us so in in part C we'll um we're +asked to find the lud composition this + + align:start position:0% +asked to find the lud composition this + + + align:start position:0% +asked to find the lud composition this +means that when we do um row operations + + align:start position:0% +means that when we do um row operations + + + align:start position:0% +means that when we do um row operations +we better keep track + + align:start position:0% +we better keep track + + + align:start position:0% +we better keep track +what row operations we're doing + + align:start position:0% +what row operations we're doing + + + align:start position:0% +what row operations we're doing +exactly um in particular we'll write + + align:start position:0% +exactly um in particular we'll write + + + align:start position:0% +exactly um in particular we'll write +them down as Elementary + + align:start position:0% +them down as Elementary + + + align:start position:0% +them down as Elementary +matrices and in part D we will be asked + + align:start position:0% +matrices and in part D we will be asked + + + align:start position:0% +matrices and in part D we will be asked +to compute the complete solution and + + align:start position:0% +to compute the complete solution and + + + align:start position:0% +to compute the complete solution and +therefore um it's good to do row + + align:start position:0% +therefore um it's good to do row + + + align:start position:0% +therefore um it's good to do row +operations on the augmented Matrix a + + align:start position:0% +operations on the augmented Matrix a + + + align:start position:0% +operations on the augmented Matrix a +okay so let's do + + align:start position:0% +okay so let's do + + + align:start position:0% +okay so let's do +this um I'm going to write this well the + + align:start position:0% +this um I'm going to write this well the + + + align:start position:0% +this um I'm going to write this well the +augmented + + align:start position:0% +augmented + + + align:start position:0% +augmented +Matrix e is the following + + align:start position:0% +Matrix e is the following + + + align:start position:0% +Matrix e is the following +Beast one one + + align:start position:0% +Beast one one + + + align:start position:0% +Beast one one +one one 2 + + align:start position:0% +one one 2 + + + align:start position:0% +one one 2 +3 3 4 + + align:start position:0% +3 3 4 + + + align:start position:0% +3 3 4 +K and then 2 3 + + align:start position:0% + + + + align:start position:0% + +7 okay so first thing we we subtract row + + align:start position:0% +7 okay so first thing we we subtract row + + + align:start position:0% +7 okay so first thing we we subtract row +multiple of Row one from row two and + + align:start position:0% +multiple of Row one from row two and + + + align:start position:0% +multiple of Row one from row two and +it's exactly um -1 times the uh first + + align:start position:0% +it's exactly um -1 times the uh first + + + align:start position:0% +it's exactly um -1 times the uh first +row plus the second right so uh let me + + align:start position:0% +row plus the second right so uh let me + + + align:start position:0% +row plus the second right so uh let me +write down the corresponding elementary + + align:start position:0% +write down the corresponding elementary + + + align:start position:0% +write down the corresponding elementary +elementary Matrix that does this it's e + + align:start position:0% +elementary Matrix that does this it's e + + + align:start position:0% +elementary Matrix that does this it's e +um 2 one and it's lower diagonal with + + align:start position:0% +um 2 one and it's lower diagonal with + + + align:start position:0% +um 2 one and it's lower diagonal with +ones on the diagonal and it's going to + + align:start position:0% +ones on the diagonal and it's going to + + + align:start position:0% +ones on the diagonal and it's going to +be exactly minus1 in in the first entry + + align:start position:0% +be exactly minus1 in in the first entry + + + align:start position:0% +be exactly minus1 in in the first entry +of the second row + + align:start position:0% +of the second row + + + align:start position:0% +of the second row +okay so we get one one one + + align:start position:0% +okay so we get one one one + + + align:start position:0% +okay so we get one one one +2 0 1 2 + + align:start position:0% + + + + align:start position:0% + +1 and we copy down the third row + + align:start position:0% +1 and we copy down the third row + + + align:start position:0% +1 and we copy down the third row +okay now we subtract a multiple of the + + align:start position:0% +okay now we subtract a multiple of the + + + align:start position:0% +okay now we subtract a multiple of the +first row from the third + + align:start position:0% +first row from the third + + + align:start position:0% +first row from the third +one and + + align:start position:0% +one and + + + align:start position:0% +one and +write this + + align:start position:0% +write this + + + align:start position:0% +write this +here it's precisely we'll multi yeah + + align:start position:0% +here it's precisely we'll multi yeah + + + align:start position:0% +here it's precisely we'll multi yeah +we'll multiply the F first row by -3 and + + align:start position:0% +we'll multiply the F first row by -3 and + + + align:start position:0% +we'll multiply the F first row by -3 and +add it to the third one this is + + align:start position:0% +add it to the third one this is + + + align:start position:0% +add it to the third one this is +accomplished by the elementary Matrix + + align:start position:0% +accomplished by the elementary Matrix + + + align:start position:0% +accomplished by the elementary Matrix +E31 which is 1 1 1 -3 and then 0 + + align:start position:0% + + + + align:start position:0% + +0 okay one one one two uh zero 1 2 one + + align:start position:0% +0 okay one one one two uh zero 1 2 one + + + align:start position:0% +0 okay one one one two uh zero 1 2 one +we copy the first two rows and then the + + align:start position:0% +we copy the first two rows and then the + + + align:start position:0% +we copy the first two rows and then the +third one will be zero + + align:start position:0% +third one will be zero + + + align:start position:0% +third one will be zero +1 um K - + + align:start position:0% +1 um K - + + + align:start position:0% +1 um K - +3 and 7 - 3 * 2 7 - 6 + + align:start position:0% +3 and 7 - 3 * 2 7 - 6 + + + align:start position:0% +3 and 7 - 3 * 2 7 - 6 +1 okay we have essentially well one last + + align:start position:0% +1 okay we have essentially well one last + + + align:start position:0% +1 okay we have essentially well one last +row operation to to perform let me do it + + align:start position:0% +row operation to to perform let me do it + + + align:start position:0% +row operation to to perform let me do it +here so we'll subtract the second Row + + align:start position:0% +here so we'll subtract the second Row + + + align:start position:0% +here so we'll subtract the second Row +from the third one and we get one one + + align:start position:0% +from the third one and we get one one + + + align:start position:0% +from the third one and we get one one +one + + align:start position:0% +one + + + align:start position:0% +one +2 0 1 2 1 + + align:start position:0% +2 0 1 2 1 + + + align:start position:0% +2 0 1 2 1 +0 0 K minus + + align:start position:0% +0 0 K minus + + + align:start position:0% +0 0 K minus +5 and then + + align:start position:0% +5 and then + + + align:start position:0% +5 and then +zero and this was achieved + + align:start position:0% +zero and this was achieved + + + align:start position:0% +zero and this was achieved +by the elementary Matrix e32 which was + + align:start position:0% +by the elementary Matrix e32 which was + + + align:start position:0% +by the elementary Matrix e32 which was +one one one and then uh negative + + align:start position:0% +one one one and then uh negative + + + align:start position:0% +one one one and then uh negative +one okay because yeah we multiplied the + + align:start position:0% +one okay because yeah we multiplied the + + + align:start position:0% +one okay because yeah we multiplied the +second row by negative one and added it + + align:start position:0% +second row by negative one and added it + + + align:start position:0% +second row by negative one and added it +to the third + + align:start position:0% +to the third + + + align:start position:0% +to the third +one okay so we have the um we have we we + + align:start position:0% +one okay so we have the um we have we we + + + align:start position:0% +one okay so we have the um we have we we +got to uh Matrix which was which is + + align:start position:0% +got to uh Matrix which was which is + + + align:start position:0% +got to uh Matrix which was which is +upper + + align:start position:0% +upper + + + align:start position:0% +upper +triangular and we want to yeah we want + + align:start position:0% +triangular and we want to yeah we want + + + align:start position:0% +triangular and we want to yeah we want +to figure out for which value of the + + align:start position:0% +to figure out for which value of the + + + align:start position:0% +to figure out for which value of the +parameter K is this Matrix uh Matrix of + + align:start position:0% +parameter K is this Matrix uh Matrix of + + + align:start position:0% +parameter K is this Matrix uh Matrix of +full full rank well this pivot is this + + align:start position:0% +full full rank well this pivot is this + + + align:start position:0% +full full rank well this pivot is this +is a pivot this is a pivot and we want + + align:start position:0% +is a pivot this is a pivot and we want + + + align:start position:0% +is a pivot this is a pivot and we want +this one to be a pivot as well and that + + align:start position:0% +this one to be a pivot as well and that + + + align:start position:0% +this one to be a pivot as well and that +happens when uh K minus 5 is not zero + + align:start position:0% +happens when uh K minus 5 is not zero + + + align:start position:0% +happens when uh K minus 5 is not zero +okay so when K is different from + + align:start position:0% +okay so when K is different from + + + align:start position:0% +okay so when K is different from +five The Matrix a is a full Rank and + + align:start position:0% +five The Matrix a is a full Rank and + + + align:start position:0% +five The Matrix a is a full Rank and +therefore + + align:start position:0% +therefore + + + align:start position:0% +therefore +um the system ax equals to 237 has a + + align:start position:0% +um the system ax equals to 237 has a + + + align:start position:0% +um the system ax equals to 237 has a +unique + + align:start position:0% +unique + + + align:start position:0% +unique +solution now Part + + align:start position:0% + + + + align:start position:0% + +B for which K do we have infinitely many + + align:start position:0% +B for which K do we have infinitely many + + + align:start position:0% +B for which K do we have infinitely many +solutions so when when when when are we + + align:start position:0% +solutions so when when when when are we + + + align:start position:0% +solutions so when when when when are we +in such a + + align:start position:0% +in such a + + + align:start position:0% +in such a +situation we are in such a situation + + align:start position:0% +situation we are in such a situation + + + align:start position:0% +situation we are in such a situation +when the null space of the Matrix a is + + align:start position:0% +when the null space of the Matrix a is + + + align:start position:0% +when the null space of the Matrix a is +non-trivial um so the no space will be + + align:start position:0% +non-trivial um so the no space will be + + + align:start position:0% +non-trivial um so the no space will be +non non-trivial when this K minus + + align:start position:0% +non non-trivial when this K minus + + + align:start position:0% +non non-trivial when this K minus +5 uh number here which is was the pivot + + align:start position:0% +5 uh number here which is was the pivot + + + align:start position:0% +5 uh number here which is was the pivot +in the first case is zero + + align:start position:0% +in the first case is zero + + + align:start position:0% +in the first case is zero +so K minus 5 equals to + + align:start position:0% +so K minus 5 equals to + + + align:start position:0% +so K minus 5 equals to +zero you see yeah there's a little + + align:start position:0% +zero you see yeah there's a little + + + align:start position:0% +zero you see yeah there's a little +caveat here um when yeah K is equal to + + align:start position:0% +caveat here um when yeah K is equal to + + + align:start position:0% +caveat here um when yeah K is equal to +five we get the third row of the + + align:start position:0% +five we get the third row of the + + + align:start position:0% +five we get the third row of the +augmented Matrix 0 0 0 equal to Z this + + align:start position:0% +augmented Matrix 0 0 0 equal to Z this + + + align:start position:0% +augmented Matrix 0 0 0 equal to Z this +means that the Matrix is actually + + align:start position:0% +means that the Matrix is actually + + + align:start position:0% +means that the Matrix is actually +consistent and we indeed have a solution + + align:start position:0% +consistent and we indeed have a solution + + + align:start position:0% +consistent and we indeed have a solution +but if this entry were non zero then we + + align:start position:0% +but if this entry were non zero then we + + + align:start position:0% +but if this entry were non zero then we +would get no Solutions + + align:start position:0% +would get no Solutions + + + align:start position:0% +would get no Solutions +okay + + align:start position:0% +okay + + + align:start position:0% +okay +now off to part + + align:start position:0% + + + + align:start position:0% + +C we want to compute the lud de + + align:start position:0% +C we want to compute the lud de + + + align:start position:0% +C we want to compute the lud de +composition well we already got what the + + align:start position:0% +composition well we already got what the + + + align:start position:0% +composition well we already got what the +uh matx U is through yeah performing + + align:start position:0% +uh matx U is through yeah performing + + + align:start position:0% +uh matx U is through yeah performing +grow operations it's is this guy here + + align:start position:0% +grow operations it's is this guy here + + + align:start position:0% +grow operations it's is this guy here +let me write it + + align:start position:0% +let me write it + + + align:start position:0% +let me write it +down 1 one one 0 1 2 0 0 K - + + align:start position:0% +down 1 one one 0 1 2 0 0 K - + + + align:start position:0% +down 1 one one 0 1 2 0 0 K - +5 and when K is equal to 4 this entry is + + align:start position:0% +5 and when K is equal to 4 this entry is + + + align:start position:0% +5 and when K is equal to 4 this entry is +NE + + align:start position:0% +NE + + + align:start position:0% +NE +-1 okay and now what about the Matrix L + + align:start position:0% +-1 okay and now what about the Matrix L + + + align:start position:0% +-1 okay and now what about the Matrix L +well well how did we get to this U we + + align:start position:0% +well well how did we get to this U we + + + align:start position:0% +well well how did we get to this U we +had the Matrix a we got the Matrix U and + + align:start position:0% +had the Matrix a we got the Matrix U and + + + align:start position:0% +had the Matrix a we got the Matrix U and +what we did was first we applied + + align:start position:0% +what we did was first we applied + + + align:start position:0% +what we did was first we applied +a21 then we applied a31 E31 and then + + align:start position:0% + + + + align:start position:0% + +e32 + + align:start position:0% + + + + align:start position:0% + +so a a is we get a by inverting this + + align:start position:0% +so a a is we get a by inverting this + + + align:start position:0% +so a a is we get a by inverting this +equation so it's going to be e 21 + + align:start position:0% +equation so it's going to be e 21 + + + align:start position:0% +equation so it's going to be e 21 +inverse E31 inverse + + align:start position:0% +inverse E31 inverse + + + align:start position:0% +inverse E31 inverse +e32 inverse * U and this is + + align:start position:0% +e32 inverse * U and this is + + + align:start position:0% +e32 inverse * U and this is +our Matrix + + align:start position:0% +our Matrix + + + align:start position:0% +our Matrix +L and we know it's fairly easy to invert + + align:start position:0% +L and we know it's fairly easy to invert + + + align:start position:0% +L and we know it's fairly easy to invert +these Elementary matrices e we just yeah + + align:start position:0% +these Elementary matrices e we just yeah + + + align:start position:0% +these Elementary matrices e we just yeah +we flip the signs of the of diagonal + + align:start position:0% +we flip the signs of the of diagonal + + + align:start position:0% +we flip the signs of the of diagonal +entries Okay so + + align:start position:0% +entries Okay so + + + align:start position:0% +entries Okay so +um I'm not going to write down the the + + align:start position:0% +um I'm not going to write down the the + + + align:start position:0% +um I'm not going to write down the the +again the inverses of of these guys um + + align:start position:0% +again the inverses of of these guys um + + + align:start position:0% +again the inverses of of these guys um +I'm yeah I'm just going to write the + + align:start position:0% +I'm yeah I'm just going to write the + + + align:start position:0% +I'm yeah I'm just going to write the +product of the inverses and that's also + + align:start position:0% +product of the inverses and that's also + + + align:start position:0% +product of the inverses and that's also +very easy um to to compute because when + + align:start position:0% +very easy um to to compute because when + + + align:start position:0% +very easy um to to compute because when +we invert the signs we just um send the + + align:start position:0% +we invert the signs we just um send the + + + align:start position:0% +we invert the signs we just um send the +numbers in + + align:start position:0% +numbers in + + + align:start position:0% +numbers in +the + + align:start position:0% +the + + + align:start position:0% +the +their corresponding entry available I + + align:start position:0% +their corresponding entry available I + + + align:start position:0% +their corresponding entry available I +mean the following thing so minus one + + align:start position:0% +mean the following thing so minus one + + + align:start position:0% +mean the following thing so minus one +becomes a one + + align:start position:0% +becomes a one + + + align:start position:0% +becomes a one +and uh it comes here in its respective + + align:start position:0% + + + + align:start position:0% + +entry for E yeah for E + + align:start position:0% +entry for E yeah for E + + + align:start position:0% +entry for E yeah for E +31 this becomes we flip the sign first + + align:start position:0% +31 this becomes we flip the sign first + + + align:start position:0% +31 this becomes we flip the sign first +three and we plug it in + + align:start position:0% +three and we plug it in + + + align:start position:0% +three and we plug it in +here and for e32 we we flip the sign of + + align:start position:0% +here and for e32 we we flip the sign of + + + align:start position:0% +here and for e32 we we flip the sign of +this guy becomes one and we plug it in + + align:start position:0% +this guy becomes one and we plug it in + + + align:start position:0% +this guy becomes one and we plug it in +here + + align:start position:0% +here + + + align:start position:0% +here +okay so give me a few moments to erase + + align:start position:0% +okay so give me a few moments to erase + + + align:start position:0% +okay so give me a few moments to erase +the board and then I I'll do part + + align:start position:0% + + + + align:start position:0% + +four okay we're back and we're going to + + align:start position:0% +four okay we're back and we're going to + + + align:start position:0% +four okay we're back and we're going to +do Part D now + + align:start position:0% +do Part D now + + + align:start position:0% +do Part D now +um okay so we need to find the complete + + align:start position:0% +um okay so we need to find the complete + + + align:start position:0% +um okay so we need to find the complete +solution of the system for all K and we + + align:start position:0% +solution of the system for all K and we + + + align:start position:0% +solution of the system for all K and we +saw that for k equal to 5 the system um + + align:start position:0% +saw that for k equal to 5 the system um + + + align:start position:0% +saw that for k equal to 5 the system um +had many many solutions and for K not + + align:start position:0% +had many many solutions and for K not + + + align:start position:0% +had many many solutions and for K not +equal to 5 it had only one okay so first + + align:start position:0% +equal to 5 it had only one okay so first + + + align:start position:0% +equal to 5 it had only one okay so first +let's uh look at the case k not equal to + + align:start position:0% +let's uh look at the case k not equal to + + + align:start position:0% +let's uh look at the case k not equal to +5 when the Matrix a was was + + align:start position:0% +5 when the Matrix a was was + + + align:start position:0% +5 when the Matrix a was was +invertible um the well we can it's it's + + align:start position:0% +invertible um the well we can it's it's + + + align:start position:0% +invertible um the well we can it's it's +not hard to see what the solution of the + + align:start position:0% +not hard to see what the solution of the + + + align:start position:0% +not hard to see what the solution of the +system then is um it's going to be let + + align:start position:0% +system then is um it's going to be let + + + align:start position:0% +system then is um it's going to be let +me just write it down + + align:start position:0% + + + + align:start position:0% + +so when K is not equal to + + align:start position:0% +so when K is not equal to + + + align:start position:0% +so when K is not equal to +5 this was non zero therefore um X3 + + align:start position:0% +5 this was non zero therefore um X3 + + + align:start position:0% +5 this was non zero therefore um X3 +needs to be zero + + align:start position:0% +needs to be zero + + + align:start position:0% +needs to be zero +right when X3 is zero we have X2 + 2 * + + align:start position:0% +right when X3 is zero we have X2 + 2 * + + + align:start position:0% +right when X3 is zero we have X2 + 2 * +X3 so X2 + 0 = 1 therefore X2 is + + align:start position:0% +X3 so X2 + 0 = 1 therefore X2 is + + + align:start position:0% +X3 so X2 + 0 = 1 therefore X2 is +1 and then we go back to the first row + + align:start position:0% +1 and then we go back to the first row + + + align:start position:0% +1 and then we go back to the first row +we have X1 + X2 + X3 = 2 so X1 + 1 + 0 = + + align:start position:0% +we have X1 + X2 + X3 = 2 so X1 + 1 + 0 = + + + align:start position:0% +we have X1 + X2 + X3 = 2 so X1 + 1 + 0 = +2 so X1 + 1 = 2 and therefore X1 is + + align:start position:0% +2 so X1 + 1 = 2 and therefore X1 is + + + align:start position:0% +2 so X1 + 1 = 2 and therefore X1 is + + align:start position:0% + + + align:start position:0% +good now what + + align:start position:0% +good now what + + + align:start position:0% +good now what +about k equal to + + align:start position:0% +about k equal to + + + align:start position:0% +about k equal to +5 then we see that X3 is a free variable + + align:start position:0% +5 then we see that X3 is a free variable + + + align:start position:0% +5 then we see that X3 is a free variable +Okay so the solution will be X1 X2 + + align:start position:0% + + + + align:start position:0% + +X3 three can be X3 can be + + align:start position:0% +X3 three can be X3 can be + + + align:start position:0% +X3 three can be X3 can be +any number + + align:start position:0% +any number + + + align:start position:0% +any number +c from the second row we'll get the + + align:start position:0% +c from the second row we'll get the + + + align:start position:0% +c from the second row we'll get the +value of X2 it's 1 - 2 * X3 so 1 - 2 * + + align:start position:0% +value of X2 it's 1 - 2 * X3 so 1 - 2 * + + + align:start position:0% +value of X2 it's 1 - 2 * X3 so 1 - 2 * +C and uh X1 is 2 minus X it's 2 2 - X1 - + + align:start position:0% +C and uh X1 is 2 minus X it's 2 2 - X1 - + + + align:start position:0% +C and uh X1 is 2 minus X it's 2 2 - X1 - +x sorry 2 * 2 - X2 - X3 so let me + + align:start position:0% +x sorry 2 * 2 - X2 - X3 so let me + + + align:start position:0% +x sorry 2 * 2 - X2 - X3 so let me +rewrite this as 2 minus X2 is 1 + + align:start position:0% +rewrite this as 2 minus X2 is 1 + + + align:start position:0% +rewrite this as 2 minus X2 is 1 +minus chalk 2 C minus c 1 - 2 c + + align:start position:0% +minus chalk 2 C minus c 1 - 2 c + + + align:start position:0% +minus chalk 2 C minus c 1 - 2 c +c + + align:start position:0% +c + + + align:start position:0% +c +okay so we'll decompose this Vector here + + align:start position:0% +okay so we'll decompose this Vector here + + + align:start position:0% +okay so we'll decompose this Vector here +into a component which is independent of + + align:start position:0% +into a component which is independent of + + + align:start position:0% +into a component which is independent of +c and a component which is a multiple of + + align:start position:0% +c and a component which is a multiple of + + + align:start position:0% +c and a component which is a multiple of +C okay so this is um 2 - 1 should be 1 1 + + align:start position:0% +C okay so this is um 2 - 1 should be 1 1 + + + align:start position:0% +C okay so this is um 2 - 1 should be 1 1 +Z plus C + + align:start position:0% + + + + align:start position:0% + +* we'll have 2 C minus c c so C * + + align:start position:0% +* we'll have 2 C minus c c so C * + + + align:start position:0% +* we'll have 2 C minus c c so C * +1 uh here we'll have minus 2 C so -2 and + + align:start position:0% +1 uh here we'll have minus 2 C so -2 and + + + align:start position:0% +1 uh here we'll have minus 2 C so -2 and +here we'll have + + align:start position:0% +here we'll have + + + align:start position:0% +here we'll have +one and thus we get the particular + + align:start position:0% +one and thus we get the particular + + + align:start position:0% +one and thus we get the particular +solution for the system and the special + + align:start position:0% +solution for the system and the special + + + align:start position:0% +solution for the system and the special +solution for the + + align:start position:0% +solution for the + + + align:start position:0% +solution for the +system okay we're kind of done here uh + + align:start position:0% +system okay we're kind of done here uh + + + align:start position:0% +system okay we're kind of done here uh +if you're at an exam you should + + align:start position:0% +if you're at an exam you should + + + align:start position:0% +if you're at an exam you should +immediately start the next problem good + + align:start position:0% +immediately start the next problem good + + + align:start position:0% +immediately start the next problem good +luck and I'll see you later \ No newline at end of file diff --git a/FBpe3xFvPrQ.txt b/FBpe3xFvPrQ.txt new file mode 100644 index 0000000000000000000000000000000000000000..ba940bfc04f48a483e06ba15802c5c9ea746767e --- /dev/null +++ b/FBpe3xFvPrQ.txt @@ -0,0 +1,1776 @@ +The following content is +provided under a Creative + +Commons license. + +Your support will help MIT +OpenCourseWare continue to + +offer high quality educational +resources for free. + +To make a donation or view +additional materials from + +hundreds of MIT courses, visit +MIT OpenCourseWare at + +ocw.mit.edu. + +PROFESSOR: Good morning, +everybody. + +Let's go back to +where we were. + +We were talking about abstract +data types and the notion of + +object oriented programming. + +And in particular, the role +of classes in all of that. + +A lot of people think this +notion of object oriented + +programming is a new notion. + +In fact, it's not. + +It's been around for probably +at least 35 + +years, maybe even longer. + +But it's only been widely +practiced for maybe 15 years. + +Even that to most of you will +seem like a long time. + +It started in the mid 1970s +when people began to write + +articles explaining this +advantage of the approach to + +programming. + +And at about the same time, +the language Smalltalk was + +developed at Xerox Park and +CLU developed at MIT. + +And they were the first +languages that, in an elegant + +way, provided linguistic support +for this style of + +programming. + +But it didn't really take off +in the public until the + +introduction of Java, +considerably later. + +And Java was the first popular +language to support object + +oriented programming. + +After that there was C++, which +supports it in not a + +very elegant but a usable way. + +And today probably Python is the +fastest growing language + +supporting object oriented +programming. + +It's used widely, and +that's one of the + +reasons we teach it here. + +As I said, at the bottom of it +all, the most fundamental + +notion is that of an +abstract data type. + +And the idea is that we can +extend our programming + +language by adding user +defined types. + +And we'll shortly see why that's +such a useful thing. + +And that these types can be used +just as easily as any of + +the built in types. + +Why do we call them abstract +data types rather than just + +data types? + +We do that because we are +essentially going to define + +for each type an interface. + +And essentially, what the +interface does is it explains + +what the methods do. + +What do I mean by +what they do? + +What they do at the level of the +user, not how they do it. + +That, of course, is the way +the built in types work. + +It wasn't until Tuesday that you +understood how Python made + +dicts do what they do. + +Before then, I just explained, +that you could put in a key + +and a value, and you could +look it up and do an + +associative retrieval. + +It was maybe not magic, but it +was wonderful that you could + +do this and not have to bother +your heads with how it was + +made to work. + +And that was because we +provided, or the designers of + +Python provided, an interface +that lets you use it. + +We'll do the same thing with +the abstract data types. + +The key idea here is one we've +talked about before and that's + +a specification. + +It is the specification of a +type, or of a function, or of + +a method, that tells us +what that thing does. + +And we'll now until the end of +the term try and maintain a + +very clear distinction between +specifications and + +implementations. + +Let's look at an example. + +So the example should +be familiar to you. + +You will remember that on +Tuesday at the start of the + +lecture, we looked at how we +could use hashing to implement + +a set of integers. + +And I explained to you that I +wasn't very happy with the + +implementation because +of the way it + +used this global variable. + +Now we're going to see a much +more elegant approach. + +So I'm going to define a new +abstract type called intSet. + +I do that by writing the word, +class, followed by + +the name of the class. + +And then there's this funny +thing saying that it is a + +subclass of objects. + +Ignore that for now. + +And I'm going to come +back to it later. + +But fundamentally what it's +saying is that every instance + +of intSet is an object. + +That's not very interesting +because everything in Python + +is an object. + +So from an information theoretic +point of view, + +there's no information here. + +Later we'll see that we can use +this mechanism in a more + +interesting way. + +Now let's look at the methods. + +So first I tell you a comment, +it's a set of integers. + +Then I've got this funny +method called underbar + +underbar init. + +Whenever you see something with +an underbar underbar in + +its name, it has a special +status in Python that lets us + +do elegant things +with the syntax. + +What will happen every time I +create a new object of type + +intSet, the underbar underbar +init method, or function, of + +the class will be executed +on that object. + +What it will do, in this case, +is introduce two attributes of + +the object. + +The attributes are numBuckets +which is now replacing the + +global variable we looked +at last time. + +And I've arbitrarily +chosen 47. + +And Vals. + +This will be the hash table +itself containing the values. + +And then, exactly as we did +on Tuesday, I'm going to + +initialize the values so that +each element of this list is + +now an empty list. + +Now what's going on with this +funny notion of self. + +Let's look at an example here. + +I'm going to say s equals +intSet open close. + +This will create a new intSet +object, execute the underbar + +underbar init. + +So if, for example, I print +self.numBuckets-- + +whoops, can't do that because +self is not defined in this + +environment. + +Self was a local variable to +underbar underbar init. + +In fact, the formal parameter. + +But I can write s.numBuckets, +and I'll see it's 47. + +NumBuckets and Val are +now attributes of s. + +Attributes of the instance +s of the class intSet. + +And I [[UNINTELLIGIBLE] + +what we would expect. + +Yes? + +AUDIENCE: You didn't put any +object in between the + +parentheses. + +PROFESSOR: Yes. + +So that-- + +the question is well, it looks +like underbar underbar intSet + +or underbar underbar init +has a formal parameter. + +And I've given it no + +corresponding actual parameter. + +AUDIENCE: [INAUDIBLE] + +PROFESSOR: Yes. + +Let me finish. + +So that's what it looks like. + +And that's the magic +of this syntax. + +It automatically passes +an implicit object, + +or it creates one. + +It's a very special role for +underbar underbar init. + +Self is used to refer to the +object being created. + +I'm going to come back in a +minute to discuss more fully + +the concept of self and +how it's used here. + +So just give me a minute +to get there. + +The next thing we +see is hashE. + +This is something we looked +at again on Tuesday. + +It's a private function in this +case that I don't intend + +to be used outside the class. + +So if we think of the +specifications here, the + +interface of the class, it +does not include hashE. + +That's what private +means here. + +This is a convention. + +It's not enforced +by the language. + +And unfortunately, as we'll see, +a lot of useful things + +are not enforced by +the language. + +But nevertheless, good +programmers follow the + +conventions. + +And we expect you guys to do so +as well because, of course, + +you're good programmers. + +So this doesn't do anything +very exciting. + +It's just what we saw. + +Insert is more interesting. + +Let's look at what that does. + +It apparently takes two +arguments, the formals named + +self and E and inserts +E into self.vals. + +However, if we go look at the +code that uses it in say + +testone what you'll note is I'm +saying for i in range 40-- + +this is just like the testone +we looked at Tuesday. + +I'm going to say +s.insert of i. + +It looks like I'm calling insert +with only one argument, + +but as we discussed last time, +this s before the dot is + +actually the first argument +to the method insert. + +And so it's getting two +arguments really. + +And by convention, that implicit +first argument is + +always called self in Python. + +It's not enforced. + +You could call it George if you +preferred, or Alice, or + +whatever you like. + +But if you do, you will confuse +the heck out of + +anybody who ever reads your +code, including any + +TA you ask for help. + +So please do use self. + +It's just a name. + +It has nothing to do with +what a philosopher, or a + +psychologist, or an ethicist +might think as the concept of + +self, this wonderful +elevated concept. + +It's none of those. + +It's just a name. + +But stick to using that name. + +So if we go back, I can insert +a bunch of things. + +I'm going to then print s. + +That's kind of interesting. + +UnderBar underbar STR, underbar +underbar is one of + +those special names as well. + +The code is pretty simple. + +All it is is returning a string + +representation of the set. + +And it could be anything +you want. + +I chose sort of a conventional +way of denoting sets. + +What's interesting +is that it gets + +automatically called by print. + +So when I write the command, +print s, in test one, the + +Python interpreter is smart +enough to know oh, I better + +take s, convert it to a string, +and then print it. + +How does it know to convert +it to a string? + +It automatically invokes the +underbar underbar STR method. + +And then the other operation +is member, which again is + +exactly what we looked +at before. + +But you'll notice in this code +that uses intSets, I make no + +reference to the data attributes +of the class + +directly, or I shouldn't. + +You'll notice that I wrote +evil next to s.vals. + +Python will let me do +it, but I shouldn't. + +Why shouldn't I do it? + +Why am I saying this is evil? + +Well, would you be happy if you +got a message saying IDLE + +was changed. + +Please download a new version +and the new version happened + +to have a different + +implementation of lists or dicts. + +And it caused all of your +programs to stop working. + +You would be pretty unhappy. + +Now why won't that happen? + +Because your programs don't +depend, in any way, on the way + +in which people chose to +implement those built in types + +because you programmed to the +specification of the types, + +not to the implementation. + +The specification of intSet +did not mention Vals or + +numBuckets. + +Therefore, as the implementer of +that class, I'm entitled to + +go back and change it. + +So I'm not going to use +a hash table at all. + +I'm going to do something +else. + +I'm going to use a red, black +tree, or some other fancy + +implementation. + +I'm allowed to do that. + +And if I make that change, and +Vals disappears and numBuckets + +disappears, your program should +continue to work so + +long as I still meet +the specification. + +The minute you go in and +directly access the variables + +of the class, those attributes, +you have used + +things that do not appear +in this specification. + +And if I change the +implementation, your program + +might break. + +So you shouldn't do that. + +Does that make sense +to everybody? + +It's a very important concept. + +The concept is known +as data hiding. + +It is really the most important +development that + +makes abstract data +types useful. + +It gives them the same status +as the built in types. + +The minute you choose to +ignore this, you do + +so at your own peril. + +Some programming languages, like +Java, provide a mechanism + +to enforce data hiding. + +The designers of Python, for +reasons I do not understand, + +chose not to. + +I think it is a flaw +in the language. + +The things we're hiding are +the instance variable. + +Those are the variables +associated with each instance + +of the class. + +We should also hide +class variables. + +We haven't seen those yet, +and we'll see them later. + +The instance variables, we get +a new copy of each time we + +created a new instance +of the class, a new + +intSet in this case. + +The class variables +are associated + +with the class itself. + +And you get only one +copy of them. + +Later on, we'll see an +example where class + +variables are useful. + +All right. + +So let's run this just to +make sure it works. + +It does what we would expect. + +True/False. + +And then you'll see +this nice string + +representation of the set. + +And then just to show you what +happens when you do the evil + +thing, I printed as we did +last time the actual + +list that came out. + +Let's now look at a more +interesting example. + +And the idea I want to convey +here is how we use classes and + +abstract data types to +design programs. + +So imagine that you're writing a +program to keep track of all + +the students, faculty, and +maybe staff at MIT. + +It's certainly possible to write +that program without + +using any classes. + +For each student, you might +give them a family name, a + +given name, a home address, +years, grades, et cetera. + +And you could do this with some +complicated combination + +of lists and dictionaries. + +But it wouldn't be +very elegant. + +So what I want to do before +writing that program-- + +and I won't actually +write that program. + +I'll just write some of the +classes we can use-- + +I want to pull back and +think about what + +abstractions would be useful. + +So this style of programming +in which you organize your + +programs around abstract data +types says before we write the + +code in detail, we think about +these types that would make it + +easy to write the code. + +So for example, if you were +a finance student, and you + +wanted to write some code +dealing with markets, you + +might want to have an +abstraction of a government + +bond, and another abstraction +of an equity, and an + +extraction of a call option. + +Whatever you want it. + +But you'd say I want to think at +that level of abstraction. + +I don't want to think about +lists, and dicts, and floats. + +I just want to think about +options, which have a strike + +price, a date, and +things like that. + +Similarly, as I'm working on +this database for MIT, I want + +to think about abstractions +of students, and + +faculty, and staff. + +I'm also going to use what's +called inheritance to set up a + +hierarchy of these. + +And the reason I'm going to do +that is I want to be able to + +share a code. + +I know that there will be +certain similarities between + +students and faculty. + +Some differences too. + +But I want to begin by saying +what's not different? + +What's similar? + +What's the same? + +So that I only have to +implement it once and + +get to reuse it. + +So if I pull back and say is +there an abstraction that + +covers the shared attributes of +students, and faculty, and + +staff, I might say +it's a person. + +They're all people. + +And it's arguable whether every +faculty member is a + +human being, but for +now let's pretend. + +And so I'm going to start with +this abstraction person. + +I'm going to import something +called DateTime. + +I'll show you what we're doing +when we get there. + +But it's like we've imported +math before. + +This is a class somebody else +wrote that deals with dates + +and time in a fairly +reasonable way. + +So I'm going to import that +here into person. + +Probably didn't need +to import it twice. + +Maybe I'll just simplify it by +getting rid of this one. + +UnderBar underbar init +here will create a + +person with name 'Name'. + +And you'll notice what I'm doing +here is introducing an + +extra attribute lastName +-- self.lastName. + +And that's because I just want +to make life easy for myself. + +I figure I'll want to find +the last name frequently. + +Let's once and for all get it +and put it in something. + +And I'm going to initialize +birthday to none. + +The next attribute, or the next +method, is get lastName. + +I have that here because I +don't want users of this + +abstraction to even know that +I have an attribute + +self.lastname. + +That's part of the +implementation. + +And so I have this method +that fetches it. + +And you'll see as you build +classes that you often have + +things called get. + +And those are typically methods +that return some + +information about an instance +of the class. + +You'll also frequently have set +methods, for example, set + +birthday that gives values to +instances of the class. + +More interestingly, +I have get age. + +And that's using some of the +built in operations on + +DateTime conveniently. + +It allows me to subtract one +date from another and get a + +number of days. + +So this will allow me to return +somebody's age in days. + +Then I've got another underbar +underbar method we + +haven't seen yet. + +lt stands for less than. + +Not a big surprise. + +And I'm going to use this to +order names, or order people. + +Why am I using a special +operator rather than just + +putting in the method +L-E-S-S-T-H. A-N? + +E-N? + +I'm doing that because I want +to be able to write things + +like p1 less than +p2 in my code. + +And Python will take that and +turn it into the underbar + +underbar LT. + +Better yet, if I have a list say +of person's, I can use the + +built in sort operator on that +list, and it will be smart + +enough to know when it's +comparing two people to do the + +sort to use the underbar +underbar LT. + +Very convenient kind of thing. + +Let's look at an example. + +Let's look at some code. + +So I'm going to set me to John +Guttag, and him to Barack + +Hussein Obama, her to Madonna. + +And we'll print some things. + +So I printed him, and I printed +him.getlastName. + +I can now set some birthdays. + +Let's look at this line. + +How do you feel about +him.birthday equals 8/4/61? + +We'll come back to it. + +But I want you to +think about it. + +And we see that Obama is-- + +well, we see their ages here. + +Actually, we see that +Madonna is older. + +She looks really old when you +look at that number of days, + +doesn't it. + +Maybe she is. + +Now what's going +to happen here? + +I messed up. + +And I messed up because I went +in and directly accessed the + +instance variable and assigned +it what I thought was a + +reasonable representation +of a birthdate. + +But I shouldn't have because +that's not even the + +appropriate type. + +It's a string rather than +something from DateTime. + +So again, we see the impact of +my having done this evil thing + +of violating the abstraction +boundary and stuck in there + +try to directly access +an instance variable. + +We can do some comparisons. + +And what we see is that I'm +not less than Madonna. + +I guess that's OK. + +You with me so far? + +I can make a list of these +things and print the list. + +So it does a fairly nice job +calling the underbar underbar + +STR operator. + +And you'll note I had no trouble +throwing objects of + +type person into the list. + +No different than putting +ints, or floats, + +or any of the built-ins. + +So it all works nicely. + +And then I can sort +it and print that. + +And now the lists come out in a +different order because it's + +using the underbar underbar LT +operator to sort the elements. + +All of this is just by way of +showing you how convenient it + +is to write code that uses +a data abstraction. + +If we go back and look at the +code, we'll see that once + +again person was a subclass +of object. + +That's why we can do all +these things we've + +been doing with it. + +But now I'm going to start +using the hierarchy. + +MIT people are special. + +I hate to say that because +I know we have non-MIT + +people in the room. + +But MIT people are special. + +Well here's at least +one of the special + +attributes of MIT people. + +They all have an ID. + +So I'm now going to say +an MIT person is a + +special subclass of person. + +So it has all of the properties +of a person. + +And the way we describe that is +it inherits the properties + +of the super class. + +And it adds a property. + +We can now assign +an ID number. + +And now we're going to see the +thing I promised to show you, + +which is a class variable. + +Next ID num is not associated +with an instance of MIT + +person, but it's associated +with the class itself. + +It's a class variable. + +I can do that because classes +are themselves objects. + +And the advantage of this is +every time I get a new + +instance of this class, I +can assign a unique ID. + +Similar to the way we were using +global variables earlier + +in the term, typically once we +have classes, we'd stop using + +global variables because we have +these class variables, + +which can serve very much the +same purpose in many cases. + +And so now every time I get a +new MIT person, I give them an + +ID and then increment the ID +number so that the next person + +will get a different one. + +So I added a property, this ID +number property, which I find + +by get ID num. + +I've also overwritten an +existing property. + +You'll note that I've changed +the definition of underbar + +underbar LT. + +So it's now saying we're going +to compare two people not on + +the basis of their +names but on the + +basis of their ID numbers. + +So let's look at some +code that uses this. + +Get rid of the other +code so it doesn't + +clutter up the screen. + +So we'll look at some +things here. + +We'll get some MIT people +called p1, p2, and p3. + +And we'll print their ID nums +by calling get ID num. + +And you can see that Barbara +Beaver gets 0, and the first + +Sue Wong gets 1, and the second +Sue Wong has ID 2. + +I can create even a +third such person. + +And now let's think about +what happens here. + +I'm going to print whether or +not p1 is less than p2 and + +whether or not p3 +is less than p2. + +What should we get +when we do this? + +Somebody? + +Pardon? + +AUDIENCE: True and false. + +PROFESSOR: I heard +a true false. + +And indeed that's right because +it's comparing IDs. + +Now, suppose I want +to compare names. + +I could if I chose do this. + +I could call person underbar +underbar LT. + +And what this says +is don't use the + +less than of the subclass. + +Go up and use the super class +one to do the comparison. + +So it's going up +and doing that. + +I can do other things. + +I can compare things +for equality. + +Let me just rip through all of +these and see what we get. + +Whoops. + +Surprise! + +Well, before we get +to that surprise-- + +and it's not actually +a surprise. + +I shouldn't have +uncommented it. + +Let's look at the other ones. + +We can say is p1 equal to p4? + +And we discover it's not. + +That's good. + +And we can say is +p4 less than p3? + +That all works. + +It's not. + +But I can't say p3 +less than p4. + +And why can't I do that? + +Why did I get an error message +when I did that? + +Yes? + +Someone wanted to answer that? + +AUDIENCE: That's because you +mix [UNINTELLIGIBLE]? + +PROFESSOR: Can you say +that more loudly? + +AUDIENCE: She's a person, +not an MIT person. + +So you didn't assign +her an ID number. + +PROFESSOR: Exactly right. + +The answer-- + +I hit somebody right +on the head. + +Now there's going to be a +traumatic brain injury. + +I'm going to get sued. + +It's going to be messy. + +Time to leave the country. + +All right. + +Because it looks at p3 less than +p4, looks at the first + +argument, which is p3, and says +OK, what's the underbar + +underbar LT associated +with p3? + +It's the one associated +with an MIT person. + +Let's go execute that. + +And then it tries to retrieve +the ID number of p4, which is + +not an MIT person, and it +gets an error message. + +All right. + +Nothing subtle. + +It's the same kind of thing +we've seen all along when we + +use type errors. + +In this case it's called an +attribute error because we've + +attempted to access an attribute +of an instance that + +doesn't exist. + +And so we could catch it. + +It's raised an exception. + +We could catch it as we looked +at Tuesday, but we're not + +going to do that because it's +really a programming bug when + +that happens. + +OK, let's continue. + +We were interested +in students. + +So we're going to continue +our hierarchy here. + +And now I'm going to introduce +a subclass of an MIT person + +called an UG, short +for undergraduate. + +Underbar underbar init is +going to call MIT person + +underbar underbar init, which +will give the UG an ID number + +and a name. + +And it's going to introduce +yet another instance + +attribute, or field, +called the year. + +And so the year, initially, +is none. + +Then I can set the year. + +Though if I try and set it as +something greater than 5, I'm + +going to raise an overflow +error called too many. + +No undergraduate should be +a year greater than 5. + +And I can get the year. + +Let's look at what happens +when we do that. + +So I'll have two UG's. + +Both happen to be +named Jane Doe. + +And then the same MIT +person as before. + +Let's run this code and see-- +well, what's going to happen? + +What's going to happen +when I say print UG1? + +The first thing it's going to do +is going to say is there an + +underbar underbar STR +associated with UGs? + +And the answer is no. + +That's OK because I know an +UG is also an MIT person. + +If I don't find it at the +lowest level class, I'll + +bounce up and say all right, is +there an underbar underbar + +STR associated with +an MIT person? + +No. + +That's OK. + +I'll go up another level and +say, well, I know an MIT + +person happens to be a person. + +And then they'll say oh, good +there is an underbar underbar + +STR associated with person. + +So I'll use that one. + +So it looks at the class. + +If it doesn't find it, it +goes to the super class. + +If it doesn't find it, it +goes to the super class. + +And it does that all the way +up until the end, where at + +worst, it will use the built-in +thing for printing + +objects because remember +everything is + +a subclass of objects. + +You don't want to do that. + +You want to have something more +elegant than object at + +location xe345, or whatever +if would have printed. + +Then we'll do some +comparisons. + +It will first look for the most +local and then work its + +way up as needed. + +OK? + +Let's keep going. + +We're going to introduce another +kind of person called + +a graduate student. + +And I'm going to write pass. + +What that means is a G is an +MIT person with no special + +properties, all the usual +properties of an MIT person. + +Does not have a year because +graduate students could be + +here more or less forever, +which goes like + +this when I say that. + +Why did I introduce the type +in the first place? + +Because it lets me +do type checking. + +I can now check whether or not a +person is a graduate student + +because an instance of G will +have all of the properties of + +an MIT person, but it will +have a different type. + +It will be type G. + +And so I can now ask the +question is the type of this + +object a G. Or is it +an MIT person and + +get a different answer. + +So I can do this. + +And if I go type of G1-- + +well, that's interesting. + +It says classmain.G. + +It's going to upset its class. + +And the class is defined at the +outermost level, which is + +called main. + +And the classes name is G, +which is what we expect. + +And so I could write something +like that. + +Type of G1 equals equals +G. And I get True. + +Ok. + +So it's a handy thing +to be able to do. + +And in fact, I'm now going to +bounce back to MIT person and + +add another method to it. + +And this happens all the time +when I'm programming that I go + +define a class, think I'm done, +and then some time later + +decide that it would be +convenient to add something + +new, another method. + +In this case, I'm now adding the +method is student, which + +returns type of self equal equal +UG or type of self equal + +equals G. + +So this will let me distinguish +a student from + +another kind of MIT person. + +So for example, if I want +to have a course list-- + +another class, this is +a subclass of object. + +You'll note I have an add +student method, which takes + +self and who, maybe +it should be whom. + +And it says, if not +who.isstudent raise type error + +not a student. + +So I'm getting some leverage +now out of this. + +Now I wouldn't need to +necessarily do this. + +I could have said if not type +of who equals G, or type of + +who equals UG. + +But I chose not to. + +The reason I chose not to is +looking ahead, I might want to + +add some other students. + +I might want to add special +student, for example. + +Or I might want to add cross +registering student as + +separate types. + +Now, the nice thing is I don't +have to make a lot of changes. + +I know there's exactly one place +in my code that defines + +what it means to be +an MIT student. + +I go back and I change +that method. + +And even if I asked whether +somebody's a student in a 100 + +different places, I only +have to make one + +change to fix my code. + +So I'm getting some modularity +by associating the method with + +the class MIT person rather +than every time + +I need to use it. \ No newline at end of file diff --git a/FscOJbr_bvs.txt b/FscOJbr_bvs.txt new file mode 100644 index 0000000000000000000000000000000000000000..f1354921ad543beb1b7e74842476b3163c67fb69 --- /dev/null +++ b/FscOJbr_bvs.txt @@ -0,0 +1,1115 @@ +align:start position:0% + +welcome back to age 20. in this section + + align:start position:0% +welcome back to age 20. in this section + + + align:start position:0% +welcome back to age 20. in this section +we want to talk about + + align:start position:0% +we want to talk about + + + align:start position:0% +we want to talk about +cause and effect and causality + + align:start position:0% +cause and effect and causality + + + align:start position:0% +cause and effect and causality +and we do this with an example which + + align:start position:0% +and we do this with an example which + + + align:start position:0% +and we do this with an example which +talks about the good guys and the bad + + align:start position:0% +talks about the good guys and the bad + + + align:start position:0% +talks about the good guys and the bad +guys there's always good guys and bad + + align:start position:0% +guys there's always good guys and bad + + + align:start position:0% +guys there's always good guys and bad +guys in the universe in this example + + align:start position:0% +guys in the universe in this example + + + align:start position:0% +guys in the universe in this example +those two groups they were fighting a + + align:start position:0% +those two groups they were fighting a + + + align:start position:0% +those two groups they were fighting a +war and after some very long and cooling + + align:start position:0% +war and after some very long and cooling + + + align:start position:0% +war and after some very long and cooling +time + + align:start position:0% +time + + + align:start position:0% +time +they were able to sign a peace treaty so + + align:start position:0% +they were able to sign a peace treaty so + + + align:start position:0% +they were able to sign a peace treaty so +this happens in this story at year + + align:start position:0% +this happens in this story at year + + + align:start position:0% +this happens in this story at year +number zero so in year zero a peace + + align:start position:0% +number zero so in year zero a peace + + + align:start position:0% +number zero so in year zero a peace +treaty is signed and the good guys they + + align:start position:0% +treaty is signed and the good guys they + + + align:start position:0% +treaty is signed and the good guys they +go back to their families they go back + + align:start position:0% +go back to their families they go back + + + align:start position:0% +go back to their families they go back +home to their planet is a spacecraft + + align:start position:0% +home to their planet is a spacecraft + + + align:start position:0% +home to their planet is a spacecraft +which is able to go with a velocity of + + align:start position:0% +which is able to go with a velocity of + + + align:start position:0% +which is able to go with a velocity of +0.6 times the speed of light + + align:start position:0% +0.6 times the speed of light + + + align:start position:0% +0.6 times the speed of light +the bad guys + + align:start position:0% +the bad guys + + + align:start position:0% +the bad guys +are still bad guys and so they develop a + + align:start position:0% +are still bad guys and so they develop a + + + align:start position:0% +are still bad guys and so they develop a +faster than the speed of light + + align:start position:0% +faster than the speed of light + + + align:start position:0% +faster than the speed of light +spacecraft follow the good guys + + align:start position:0% +spacecraft follow the good guys + + + align:start position:0% +spacecraft follow the good guys +and they succeed with the development of + + align:start position:0% +and they succeed with the development of + + + align:start position:0% +and they succeed with the development of +the spacecraft after four years + + align:start position:0% +the spacecraft after four years + + + align:start position:0% +the spacecraft after four years +so they do they follow the good guys + + align:start position:0% +so they do they follow the good guys + + + align:start position:0% +so they do they follow the good guys +and + + align:start position:0% +and + + + align:start position:0% +and +in year number five the bad guys attack + + align:start position:0% +in year number five the bad guys attack + + + align:start position:0% +in year number five the bad guys attack +and destroy the good + + align:start position:0% +and destroy the good + + + align:start position:0% +and destroy the good +guys so the challenge for you now is to + + align:start position:0% +guys so the challenge for you now is to + + + align:start position:0% +guys so the challenge for you now is to +explain the story and answer the + + align:start position:0% +explain the story and answer the + + + align:start position:0% +explain the story and answer the +following question + + align:start position:0% +following question + + + align:start position:0% +following question +when and where does the attack happen + + align:start position:0% +when and where does the attack happen + + + align:start position:0% +when and where does the attack happen +from the good guys perspective + + align:start position:0% +from the good guys perspective + + + align:start position:0% +from the good guys perspective +and when did the bad guys invent the + + align:start position:0% +and when did the bad guys invent the + + + align:start position:0% +and when did the bad guys invent the +spacecraft from the good guys + + align:start position:0% +spacecraft from the good guys + + + align:start position:0% +spacecraft from the good guys +perspective and you will see + + align:start position:0% +perspective and you will see + + + align:start position:0% +perspective and you will see +some surprising results in this another + + align:start position:0% +some surprising results in this another + + + align:start position:0% +some surprising results in this another +this + + align:start position:0% +this + + + align:start position:0% +this +so please stop the video and try to work + + align:start position:0% +so please stop the video and try to work + + + align:start position:0% +so please stop the video and try to work +this out i recommend drawing a space + + align:start position:0% +this out i recommend drawing a space + + + align:start position:0% +this out i recommend drawing a space +time diagram + + align:start position:0% +time diagram + + + align:start position:0% +time diagram +in order to get to a good picture of + + align:start position:0% +in order to get to a good picture of + + + align:start position:0% +in order to get to a good picture of +what is actually happening here + + align:start position:0% + + + + align:start position:0% + +so if we do this you find this base time + + align:start position:0% +so if we do this you find this base time + + + align:start position:0% +so if we do this you find this base time +diagram here for the bad guys so again + + align:start position:0% +diagram here for the bad guys so again + + + align:start position:0% +diagram here for the bad guys so again +there's a number of important event + + align:start position:0% +there's a number of important event + + + align:start position:0% +there's a number of important event +in year number zero + + align:start position:0% +in year number zero + + + align:start position:0% +in year number zero +the speed the the peace treaty is is + + align:start position:0% +the speed the the peace treaty is is + + + align:start position:0% +the speed the the peace treaty is is +signed and then + + align:start position:0% +signed and then + + + align:start position:0% +signed and then +the good guys they start traveling away + + align:start position:0% +the good guys they start traveling away + + + align:start position:0% +the good guys they start traveling away +with 0.6 times the speed of light so + + align:start position:0% +with 0.6 times the speed of light so + + + align:start position:0% +with 0.6 times the speed of light so +what you see here is the word line of + + align:start position:0% +what you see here is the word line of + + + align:start position:0% +what you see here is the word line of +the good + + align:start position:0% +the good + + + align:start position:0% +the good +guys in year number four + + align:start position:0% +guys in year number four + + + align:start position:0% +guys in year number four +in the reference frame of the bad guys + + align:start position:0% +in the reference frame of the bad guys + + + align:start position:0% +in the reference frame of the bad guys +they developed their spacecraft and they + + align:start position:0% +they developed their spacecraft and they + + + align:start position:0% +they developed their spacecraft and they +keep following + + align:start position:0% +keep following + + + align:start position:0% +keep following +the good guys + + align:start position:0% +the good guys + + + align:start position:0% +the good guys +and here in here number five + + align:start position:0% +and here in here number five + + + align:start position:0% +and here in here number five +the attack actually happens + + align:start position:0% +the attack actually happens + + + align:start position:0% +the attack actually happens +so if we analyze this for the good guys + + align:start position:0% +so if we analyze this for the good guys + + + align:start position:0% +so if we analyze this for the good guys +we find that the + + align:start position:0% +we find that the + + + align:start position:0% +we find that the +x position the position of the attack + + align:start position:0% +x position the position of the attack + + + align:start position:0% +x position the position of the attack +is in their spacecraft so let's figure + + align:start position:0% +is in their spacecraft so let's figure + + + align:start position:0% +is in their spacecraft so let's figure +out whether or not this is correct + + align:start position:0% +out whether or not this is correct + + + align:start position:0% +out whether or not this is correct +we find gamma times xb + + align:start position:0% +we find gamma times xb + + + align:start position:0% +we find gamma times xb +minus v + + align:start position:0% +minus v + + + align:start position:0% +minus v +times tb + + align:start position:0% +times tb + + + align:start position:0% +times tb +if you put in the numbers you find + + align:start position:0% +if you put in the numbers you find + + + align:start position:0% +if you put in the numbers you find +luckily + + align:start position:0% +luckily + + + align:start position:0% +luckily +the x position is equal to zero + + align:start position:0% + + + + align:start position:0% + +at what time did this event happen + + align:start position:0% +at what time did this event happen + + + align:start position:0% +at what time did this event happen +um here for the good guys you find gamma + + align:start position:0% +um here for the good guys you find gamma + + + align:start position:0% +um here for the good guys you find gamma +times t b minus v over c x b + + align:start position:0% +times t b minus v over c x b + + + align:start position:0% +times t b minus v over c x b +and again if you put the numbers in the + + align:start position:0% +and again if you put the numbers in the + + + align:start position:0% +and again if you put the numbers in the +attack for the good guys happens in year + + align:start position:0% +attack for the good guys happens in year + + + align:start position:0% +attack for the good guys happens in year +number four + + align:start position:0% + + + + align:start position:0% + +but then the question is + + align:start position:0% +but then the question is + + + align:start position:0% +but then the question is +when did the bad guys invent + + align:start position:0% +when did the bad guys invent + + + align:start position:0% +when did the bad guys invent +the spacecraft in the reference frame of + + align:start position:0% +the spacecraft in the reference frame of + + + align:start position:0% +the spacecraft in the reference frame of +the good guys and if you put in the + + align:start position:0% +the good guys and if you put in the + + + align:start position:0% +the good guys and if you put in the +numbers you find the invention actually + + align:start position:0% +numbers you find the invention actually + + + align:start position:0% +numbers you find the invention actually +happens + + align:start position:0% +happens + + + align:start position:0% +happens +in year number five + + align:start position:0% +in year number five + + + align:start position:0% +in year number five +so the attack happens before the + + align:start position:0% +so the attack happens before the + + + align:start position:0% +so the attack happens before the +spacecraft is invented in the reference + + align:start position:0% +spacecraft is invented in the reference + + + align:start position:0% +spacecraft is invented in the reference +frame of the good guys + + align:start position:0% +frame of the good guys + + + align:start position:0% +frame of the good guys +and this clearly + + align:start position:0% +and this clearly + + + align:start position:0% +and this clearly +violates + + align:start position:0% +violates + + + align:start position:0% +violates +you cannot use the device which is not + + align:start position:0% +you cannot use the device which is not + + + align:start position:0% +you cannot use the device which is not +even invented yet unless you + + align:start position:0% +even invented yet unless you + + + align:start position:0% +even invented yet unless you +travel faster than the speed of light + + align:start position:0% +travel faster than the speed of light + + + align:start position:0% +travel faster than the speed of light +you travel in time + + align:start position:0% +you travel in time + + + align:start position:0% +you travel in time +all right i find this a really funny and + + align:start position:0% +all right i find this a really funny and + + + align:start position:0% +all right i find this a really funny and +geeky example and the reason why this + + align:start position:0% +geeky example and the reason why this + + + align:start position:0% +geeky example and the reason why this +doesn't work out why it's geeky is that + + align:start position:0% +doesn't work out why it's geeky is that + + + align:start position:0% +doesn't work out why it's geeky is that +they travel faster than the speed of + + align:start position:0% +they travel faster than the speed of + + + align:start position:0% +they travel faster than the speed of +light + + align:start position:0% + + + + align:start position:0% + +so um + + align:start position:0% +so um + + + align:start position:0% +so um +let me conclude this this part of this + + align:start position:0% +let me conclude this this part of this + + + align:start position:0% +let me conclude this this part of this +section here with a concept question + + align:start position:0% +section here with a concept question + + + align:start position:0% +section here with a concept question +we have an event a and ask ourselves can + + align:start position:0% +we have an event a and ask ourselves can + + + align:start position:0% +we have an event a and ask ourselves can +event a cause other events so event a + + align:start position:0% +event a cause other events so event a + + + align:start position:0% +event a cause other events so event a +might be the invention of a spacecraft + + align:start position:0% +might be the invention of a spacecraft + + + align:start position:0% +might be the invention of a spacecraft +can event a cause event c + + align:start position:0% +can event a cause event c + + + align:start position:0% +can event a cause event c +event d + + align:start position:0% +event d + + + align:start position:0% +event d +or more than one event like b and c or b + + align:start position:0% +or more than one event like b and c or b + + + align:start position:0% +or more than one event like b and c or b +and d + + align:start position:0% + + + + align:start position:0% + +so note that the time axis here has + + align:start position:0% +so note that the time axis here has + + + align:start position:0% +so note that the time axis here has +units years and the x-axis has units + + align:start position:0% +units years and the x-axis has units + + + align:start position:0% +units years and the x-axis has units +light years + + align:start position:0% +light years + + + align:start position:0% +light years +again + + align:start position:0% +again + + + align:start position:0% +again +you know stop your video here think + + align:start position:0% +you know stop your video here think + + + align:start position:0% +you know stop your video here think +about the answer maybe you draw in the + + align:start position:0% +about the answer maybe you draw in the + + + align:start position:0% +about the answer maybe you draw in the +space-time diagram in order to find the + + align:start position:0% +space-time diagram in order to find the + + + align:start position:0% +space-time diagram in order to find the +answer + + align:start position:0% +answer + + + align:start position:0% +answer +and the answer is the correct answer is + + align:start position:0% +and the answer is the correct answer is + + + align:start position:0% +and the answer is the correct answer is +c only when c can be caused because only + + align:start position:0% +c only when c can be caused because only + + + align:start position:0% +c only when c can be caused because only +c + + align:start position:0% +c + + + align:start position:0% +c +lies within what we call the light cone + + align:start position:0% +lies within what we call the light cone + + + align:start position:0% +lies within what we call the light cone +of event a + + align:start position:0% +of event a + + + align:start position:0% +of event a +in order to impact in order to cause an + + align:start position:0% +in order to impact in order to cause an + + + align:start position:0% +in order to impact in order to cause an +effect on any other event + + align:start position:0% +effect on any other event + + + align:start position:0% +effect on any other event +the message needs to be traveling + + align:start position:0% +the message needs to be traveling + + + align:start position:0% +the message needs to be traveling +with speed + + align:start position:0% +with speed + + + align:start position:0% +with speed +smaller than the speed of light + + align:start position:0% +smaller than the speed of light + + + align:start position:0% +smaller than the speed of light +so that means that in order for to reach + + align:start position:0% +so that means that in order for to reach + + + align:start position:0% +so that means that in order for to reach +event + + align:start position:0% +event + + + align:start position:0% +event +c + + align:start position:0% +c + + + align:start position:0% +c +we can you know design a spacecraft or + + align:start position:0% +we can you know design a spacecraft or + + + align:start position:0% +we can you know design a spacecraft or +we can send a light beam + + align:start position:0% +we can send a light beam + + + align:start position:0% +we can send a light beam +to this event + + align:start position:0% +to this event + + + align:start position:0% +to this event +or to this in this direction and then + + align:start position:0% +or to this in this direction and then + + + align:start position:0% +or to this in this direction and then +just wait a little bit + + align:start position:0% +just wait a little bit + + + align:start position:0% +just wait a little bit +in order to make any sort of impact on + + align:start position:0% +in order to make any sort of impact on + + + align:start position:0% +in order to make any sort of impact on +event c we cannot travel faster than the + + align:start position:0% +event c we cannot travel faster than the + + + align:start position:0% +event c we cannot travel faster than the +speed of light which would be necessary + + align:start position:0% +speed of light which would be necessary + + + align:start position:0% +speed of light which would be necessary +in order to reach when d + + align:start position:0% +in order to reach when d + + + align:start position:0% +in order to reach when d +and we can also not go backwards in time + + align:start position:0% +and we can also not go backwards in time + + + align:start position:0% +and we can also not go backwards in time +with messages in order to reach event b \ No newline at end of file diff --git a/G8B_Wzmeo_8.txt b/G8B_Wzmeo_8.txt new file mode 100644 index 0000000000000000000000000000000000000000..55d20705eb7eced741da60346493529c7a76c939 --- /dev/null +++ b/G8B_Wzmeo_8.txt @@ -0,0 +1,307 @@ +align:start position:0% + +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +T that came in that little bit of time + + align:start position:0% +T that came in that little bit of time + + + align:start position:0% +T that came in that little bit of time +see how it's kind of red why do you + + align:start position:0% +see how it's kind of red why do you + + + align:start position:0% +see how it's kind of red why do you +think it's a little red it's all the + + align:start position:0% + + + + align:start position:0% + +iron and this one + + align:start position:0% + + + + align:start position:0% + +here there we + + align:start position:0% +here there we + + + align:start position:0% +here there we +go there's another one now if we did + + align:start position:0% +go there's another one now if we did + + + align:start position:0% +go there's another one now if we did +phosphate measurements on these I would + + align:start position:0% +phosphate measurements on these I would + + + align:start position:0% +phosphate measurements on these I would +guess it would be + + align:start position:0% +guess it would be + + + align:start position:0% +guess it would be +zero I know it would be zero cuz we + + align:start position:0% +zero I know it would be zero cuz we + + + align:start position:0% +zero I know it would be zero cuz we +tried it last week okay so that's uh and + + align:start position:0% +tried it last week okay so that's uh and + + + align:start position:0% +tried it last week okay so that's uh and +then you can take this you can measure + + align:start position:0% +then you can take this you can measure + + + align:start position:0% +then you can take this you can measure +the + + align:start position:0% +the + + + align:start position:0% +the +flow um measure the you know volume time + + align:start position:0% +flow um measure the you know volume time + + + align:start position:0% +flow um measure the you know volume time +you left it on surface area and you can + + align:start position:0% +you left it on surface area and you can + + + align:start position:0% +you left it on surface area and you can +get a number of liters per square you + + align:start position:0% +get a number of liters per square you + + + align:start position:0% +get a number of liters per square you +know for for a square foot or per square + + align:start position:0% +know for for a square foot or per square + + + align:start position:0% +know for for a square foot or per square +meter and then you can begin to do this + + align:start position:0% +meter and then you can begin to do this + + + align:start position:0% +meter and then you can begin to do this +in a number of spots and actually + + align:start position:0% +in a number of spots and actually + + + align:start position:0% +in a number of spots and actually +integrate it and come up with a total + + align:start position:0% +integrate it and come up with a total + + + align:start position:0% +integrate it and come up with a total +flux make sense and you're going to see + + align:start position:0% +flux make sense and you're going to see + + + align:start position:0% +flux make sense and you're going to see +I think Charlie is doing that at Lacoy + + align:start position:0% +I think Charlie is doing that at Lacoy + + + align:start position:0% +I think Charlie is doing that at Lacoy +Bay extensively so there you go + + align:start position:0% +Bay extensively so there you go + + + align:start position:0% +Bay extensively so there you go +if somebody would be so willing is to + + align:start position:0% +if somebody would be so willing is to + + + align:start position:0% +if somebody would be so willing is to +hold on to those and let those drain out + + align:start position:0% +hold on to those and let those drain out + + + align:start position:0% +hold on to those and let those drain out +that would be + + align:start position:0% +that would be + + + align:start position:0% +that would be +great I'm going to pop these + + align:start position:0% + + + + align:start position:0% + +Lids there's one + + align:start position:0% +Lids there's one + + + align:start position:0% +Lids there's one +lid take that back up + + align:start position:0% + + + + align:start position:0% + +you know what's really cool about these + + align:start position:0% +you know what's really cool about these + + + align:start position:0% +you know what's really cool about these +CES meters is um we have a a study going + + align:start position:0% +CES meters is um we have a a study going + + + align:start position:0% +CES meters is um we have a a study going +on right now looking at uh nutrient + + align:start position:0% +on right now looking at uh nutrient + + + align:start position:0% +on right now looking at uh nutrient +outflow from the lake and you can go to + + align:start position:0% +outflow from the lake and you can go to + + + align:start position:0% +outflow from the lake and you can go to +a site like we have on the downstream + + align:start position:0% +a site like we have on the downstream + + + align:start position:0% +a site like we have on the downstream +side of the lake and you fill the bag + + align:start position:0% +side of the lake and you fill the bag + + + align:start position:0% +side of the lake and you fill the bag +with water to start and you watch it + + align:start position:0% +with water to start and you watch it + + + align:start position:0% +with water to start and you watch it +drain away it's really cool just the B + + align:start position:0% +drain away it's really cool just the B + + + align:start position:0% +drain away it's really cool just the B +water is sucked out of the + + align:start position:0% +water is sucked out of the + + + align:start position:0% +water is sucked out of the +bag that's it \ No newline at end of file diff --git a/GBL28_Tw6UQ.txt b/GBL28_Tw6UQ.txt new file mode 100644 index 0000000000000000000000000000000000000000..73466832e8e46c2438907532c5826d10d3055b2f --- /dev/null +++ b/GBL28_Tw6UQ.txt @@ -0,0 +1,257 @@ +SRAMs are organized as an array of memory +locations, where a memory access is either + +reading or writing all the bits in a single +location. + +Here we see the component layout for a 8-location +SRAM array where each location hold 6 bits + +of data. + +You can see that the individual bit cells +are organized as 8 rows (one row per location) + +by 6 columns (one column per bit in each memory +word). + +The circuitry around the periphery is used +to decode addresses and support read and write + +operations. + +To access the SRAM, we need provide enough +address bits to uniquely specify the location. + +In this case we need 3 address bits to select +one of the 8 memory locations. + +The address decoder logic sets one of the +8 wordlines (the horizontal wires in the array) + +high to enable a particular row (location) +for the upcoming access. + +The remaining wordlines are set low, disabling +the cells they control. + +The active wordline enables each of the SRAM +bit cells on the selected row, connecting + +each cell to a pair of bit lines (the vertical +wires in the array). + +During read operations the bit lines carry +the analog signals from the enabled bit cells + +to the sense amplifiers, which convert the +analog signals to digital data. + +During write operations incoming data is driven +onto the bit lines to be stored into the enabled + +bit cells. + +Larger SRAMs will have a more complex organization +in order to minimize the length, and hence + +the capacitance, of the bit lines. + +The heart of the SRAM are the bit cells. + +The typical cell has two CMOS inverters wired +in a positive feedback loop to create a bistable + +storage element. + +The diagram on the right shows the two stable +configurations. + +In the top configuration, the cell is storing +a "1" bit. + +In the bottom configuration, it's storing +a 0 bit. + +The cell provides stable storage in the sense +that as long as there's power, the noise immunity + +of the inverters will ensure that the logic +values will be maintained even if there's + +electrical noise on either inverter input. + +Both sides of the feedback loop are connected +via access FETs to the two vertical bit lines. + +When the wordline connected to the gates of +the access FETs is high, the FETs are "on", + +i.e., they will make an electrical connection +between the cell's internal circuity and the + +bitlines. + +When the wordline is low, the access FETs +are "off" and the bistable feedback loop is + +isolated from the bitlines and will happily +maintain the stored value as long as there's + +power. + +During a read operation, the drivers first +recharge all the bitlines to Vdd (i.e., a + +logical "1" value) and then disconnect, leaving +the bitlines floating at 1. + +Then the address decoder sets one of the wordlines +high, connecting a row of bit cells to their + +bitlines. + +Each cell in the selected row then pulls one +of its two bitlines to GND. + +In this example, it's the right bitline that's +pulled low. + +Transitions on the bitlines are slow since +the bitline has a large total capacitance + +and the MOSFETs in the two inverters are small +to keep the cell has small as possible. + +The large capacitance comes partly from the +bitline's length and partly from the diffusion + +capacitance of the access FETs in other cells +in the same column. + +Rather than wait for the bitline to reach +a valid logic level, sense amplifiers are + +used to quickly detect the small voltage difference +developing between the two bitlines and generate + +the appropriate digital output. + +Since detecting small changes in a voltage +is very sensitive to electrical noise, the + +SRAM uses a pair of bitlines for each bit +and a differential sense amplifier to provide + +greater noise immunity. + +As you can see, designing a low-latency SRAM +involves a lot of expertise with the analog + +behavior of MOSFETs and some cleverness to +ensure electrical noise will not interfere + +with the correct operation of the circuitry. + +Write operations start by driving the bitlines +to the appropriate values. + +In the example shown here, we want to write +a 0-bit into the cell, so the left bitline + +is set to GND and the right bitline is set +to VDD. + +As before, the address decoder then sets one +of the wordlines high, selecting all the cells + +in a particular row for the write operation. + +The drivers have much larger MOSFETs than +those in the cell's inverters, so the internal + +signals in the enabled cells are forced to +the values on the bitlines and the bistable + +circuits "flip" into the new stable configuration. + +We're basically shorting together the outputs +of the driver and the internal inverter, so + +this is another analog operation! + +This would be a no-no in a strictly digital +circuit. + +Since n-fets usually carry much higher source-drain +currents than p-fets of the same width and + +given the threshold-drop of the n-fet access +transistor, + +almost all the work of the write is performed +by the large n-fet pulldown transistor connected + +to the bitline with the 0 value, which easily +overpowers the small p-fet pullup of the inverters + +in the cell. + +Again, SRAM designers need a lot of expertise +to correctly balance the sizes of MOSFETs + +to ensure fast and reliable write operations. + +It's not hard to augment the SRAM to support +multiple read/write ports, a handy addition + +for register file circuits. + +We'll do this by adding additional sets of +wordlines, bitlines, drivers, and sense amps. + +This will give us multiple paths to independently +access the bistable storage elements in the + +various rows of the memory array. + +With an N-port SRAM, for each bit we'll need +N wordlines, 2N bitlines and 2N access FETs. + +The additional wordlines increase the effective +height of the cell and the additional bitlines + +increase the effective width of the cell and +so the area required by all these wires quickly + +dominates the size of the SRAM. + +Since both the height and width of a cell +increase when adding ports, the overall area + +grows as the square of the number of read/write +ports. + +So one has to take care not to gratuitously +add ports lest the cost of the SRAM get out + +of hand. + +In summary, the circuitry for the SRAM is +organized as an array of bit cells, with one + +row for each memory location and one column +for each bit in a location. + +Each bit is stored by two inverters connected +to form a bistable storage element. + +Reads and writes are essentially analog operations +performed via the bitlines and access FETs. + +The SRAM uses 6 MOSFETs for each bit cell. + +Can we do better? + +What's the minimum number of MOSFETs needed +to store a single bit of information? \ No newline at end of file diff --git a/GOgA8JGUiwI.txt b/GOgA8JGUiwI.txt new file mode 100644 index 0000000000000000000000000000000000000000..e2bf9bb9aabf9b534ea7221c3aee9312dd0f3940 --- /dev/null +++ b/GOgA8JGUiwI.txt @@ -0,0 +1,13523 @@ +align:start position:0% + +All right, let's get started. Uh, + + align:start position:0% +All right, let's get started. Uh, + + + align:start position:0% +All right, let's get started. Uh, +welcome back to 61200. I am the second + + align:start position:0% +welcome back to 61200. I am the second + + + align:start position:0% +welcome back to 61200. I am the second +of the three lecturers in this class. + + align:start position:0% +of the three lecturers in this class. + + + align:start position:0% +of the three lecturers in this class. +Uh, you can call me Eric. Um, and + + align:start position:0% +Uh, you can call me Eric. Um, and + + + align:start position:0% +Uh, you can call me Eric. Um, and +Binmore will be on next week. Uh so + + align:start position:0% +Binmore will be on next week. Uh so + + + align:start position:0% +Binmore will be on next week. Uh so +today we are going to uh continue our + + align:start position:0% +today we are going to uh continue our + + + align:start position:0% +today we are going to uh continue our +theme of induction and prove some even + + align:start position:0% +theme of induction and prove some even + + + align:start position:0% +theme of induction and prove some even +cooler and stronger forms of induction. + + align:start position:0% +cooler and stronger forms of induction. + + + align:start position:0% +cooler and stronger forms of induction. +Just a recap of where we were last time. + + align:start position:0% +Just a recap of where we were last time. + + + align:start position:0% +Just a recap of where we were last time. +As we've seen, we're we're growing our + + align:start position:0% +As we've seen, we're we're growing our + + + align:start position:0% +As we've seen, we're we're growing our +catalog of different proof techniques of + + align:start position:0% +catalog of different proof techniques of + + + align:start position:0% +catalog of different proof techniques of +how to prove uh different types of + + align:start position:0% +how to prove uh different types of + + + align:start position:0% +how to prove uh different types of +theorems almost by like a cookbook. If + + align:start position:0% +theorems almost by like a cookbook. If + + + align:start position:0% +theorems almost by like a cookbook. If +you want to cook this, here's how you + + align:start position:0% +you want to cook this, here's how you + + + align:start position:0% +you want to cook this, here's how you +get started. And so here's a a brief + + align:start position:0% +get started. And so here's a a brief + + + align:start position:0% +get started. And so here's a a brief +summary of this. uh if the theorem you + + align:start position:0% +summary of this. uh if the theorem you + + + align:start position:0% +summary of this. uh if the theorem you +want to prove starts with there exists + + align:start position:0% +want to prove starts with there exists + + + align:start position:0% +want to prove starts with there exists +something then a natural way to prove + + align:start position:0% +something then a natural way to prove + + + align:start position:0% +something then a natural way to prove +that is by example or by construction + + align:start position:0% +that is by example or by construction + + + align:start position:0% +that is by example or by construction +you construct a particular x star and + + align:start position:0% +you construct a particular x star and + + + align:start position:0% +you construct a particular x star and +prove that p of xstar is true and if you + + align:start position:0% +prove that p of xstar is true and if you + + + align:start position:0% +prove that p of xstar is true and if you +can do that uh then you've proved that + + align:start position:0% +can do that uh then you've proved that + + + align:start position:0% +can do that uh then you've proved that +there exists an x where p of x is true + + align:start position:0% +there exists an x where p of x is true + + + align:start position:0% +there exists an x where p of x is true +it's kind of straightforward but it lets + + align:start position:0% +it's kind of straightforward but it lets + + + align:start position:0% +it's kind of straightforward but it lets +you unwrap if I give you an expression + + align:start position:0% +you unwrap if I give you an expression + + + align:start position:0% +you unwrap if I give you an expression +starts with exist then you know your + + align:start position:0% +starts with exist then you know your + + + align:start position:0% +starts with exist then you know your +first step is try to figure out an x + + align:start position:0% +first step is try to figure out an x + + + align:start position:0% +first step is try to figure out an x +where this is true um and of course to + + align:start position:0% +where this is true um and of course to + + + align:start position:0% +where this is true um and of course to +prove p of xar you probably recur + + align:start position:0% +prove p of xar you probably recur + + + align:start position:0% +prove p of xar you probably recur +cursively use this cookbook. If you want + + align:start position:0% +cursively use this cookbook. If you want + + + align:start position:0% +cursively use this cookbook. If you want +to prove a universal uh one common way + + align:start position:0% +to prove a universal uh one common way + + + align:start position:0% +to prove a universal uh one common way +if you want to prove for all x p of x is + + align:start position:0% +if you want to prove for all x p of x is + + + align:start position:0% +if you want to prove for all x p of x is +true uh typically your first line is + + align:start position:0% +true uh typically your first line is + + + align:start position:0% +true uh typically your first line is +take an arbitrary x just give it a name + + align:start position:0% +take an arbitrary x just give it a name + + + align:start position:0% +take an arbitrary x just give it a name +x and then prove that p of x is true no + + align:start position:0% +x and then prove that p of x is true no + + + align:start position:0% +x and then prove that p of x is true no +matter what x you started with therefore + + align:start position:0% +matter what x you started with therefore + + + align:start position:0% +matter what x you started with therefore +it's true for all of them. Uh come back + + align:start position:0% +it's true for all of them. Uh come back + + + align:start position:0% +it's true for all of them. Uh come back +to induction in a second. If you're if + + align:start position:0% +to induction in a second. If you're if + + + align:start position:0% +to induction in a second. If you're if +the main thing you want to prove is an + + align:start position:0% +the main thing you want to prove is an + + + align:start position:0% +the main thing you want to prove is an +implication, P implies Q. This is if P + + align:start position:0% +implication, P implies Q. This is if P + + + align:start position:0% +implication, P implies Q. This is if P +then Q. And I want to remind you that um + + align:start position:0% +then Q. And I want to remind you that um + + + align:start position:0% +then Q. And I want to remind you that um +P implies Q is the same thing as not P + + align:start position:0% +P implies Q is the same thing as not P + + + align:start position:0% +P implies Q is the same thing as not P +or Q. We'll use this a bunch uh today. + + align:start position:0% +or Q. We'll use this a bunch uh today. + + + align:start position:0% +or Q. We'll use this a bunch uh today. +Um then uh the direct way to prove this + + align:start position:0% +Um then uh the direct way to prove this + + + align:start position:0% +Um then uh the direct way to prove this +what we call a direct argument is assume + + align:start position:0% +what we call a direct argument is assume + + + align:start position:0% +what we call a direct argument is assume +P is true and then prove Q is true. + + align:start position:0% +P is true and then prove Q is true. + + + align:start position:0% +P is true and then prove Q is true. +Because this implication we only need to + + align:start position:0% +Because this implication we only need to + + + align:start position:0% +Because this implication we only need to +prove that Q is true when P is true. If + + align:start position:0% +prove that Q is true when P is true. If + + + align:start position:0% +prove that Q is true when P is true. If +P then Q. Uh or another way to prove + + align:start position:0% +P then Q. Uh or another way to prove + + + align:start position:0% +P then Q. Uh or another way to prove +that same statement P implies Q is + + align:start position:0% +that same statement P implies Q is + + + align:start position:0% +that same statement P implies Q is +what's called the contraositive. It + + align:start position:0% +what's called the contraositive. It + + + align:start position:0% +what's called the contraositive. It +turns out P implies Q is the same + + align:start position:0% +turns out P implies Q is the same + + + align:start position:0% +turns out P implies Q is the same +statement. It's equivalent to not Q + + align:start position:0% +statement. It's equivalent to not Q + + + align:start position:0% +statement. It's equivalent to not Q +implies not P. Remember this uh symbol + + align:start position:0% +implies not P. Remember this uh symbol + + + align:start position:0% +implies not P. Remember this uh symbol +is a negation + + align:start position:0% +is a negation + + + align:start position:0% +is a negation +um flip true and false. So to do that + + align:start position:0% +um flip true and false. So to do that + + + align:start position:0% +um flip true and false. So to do that +with a direct argument we would prove + + align:start position:0% +with a direct argument we would prove + + + align:start position:0% +with a direct argument we would prove +that uh if not Q is true then not P is + + align:start position:0% +that uh if not Q is true then not P is + + + align:start position:0% +that uh if not Q is true then not P is +true. In other words, assume not Q and + + align:start position:0% +true. In other words, assume not Q and + + + align:start position:0% +true. In other words, assume not Q and +then prove not P. + + align:start position:0% +then prove not P. + + + align:start position:0% +then prove not P. +This may seem kind of magical. Why is P + + align:start position:0% +This may seem kind of magical. Why is P + + + align:start position:0% +This may seem kind of magical. Why is P +implies Q the same as not Q implies not + + align:start position:0% +implies Q the same as not Q implies not + + + align:start position:0% +implies Q the same as not Q implies not +P? But it actually follows directly from + + align:start position:0% +P? But it actually follows directly from + + + align:start position:0% +P? But it actually follows directly from +this equivalence. If you look at not Q + + align:start position:0% +this equivalence. If you look at not Q + + + align:start position:0% +this equivalence. If you look at not Q +implies not P. Uh this is the same thing + + align:start position:0% +implies not P. Uh this is the same thing + + + align:start position:0% +implies not P. Uh this is the same thing +as let me go over here. Not not Q or not + + align:start position:0% +as let me go over here. Not not Q or not + + + align:start position:0% +as let me go over here. Not not Q or not +P, + + align:start position:0% +P, + + + align:start position:0% +P, +right? because it implies is the same + + align:start position:0% +right? because it implies is the same + + + align:start position:0% +right? because it implies is the same +thing as taking an or if you negate the + + align:start position:0% +thing as taking an or if you negate the + + + align:start position:0% +thing as taking an or if you negate the +first the part on the left and not not Q + + align:start position:0% +first the part on the left and not not Q + + + align:start position:0% +first the part on the left and not not Q +is the same as Q. + + align:start position:0% +is the same as Q. + + + align:start position:0% +is the same as Q. +Okay, so this was uh not Q implies not P + + align:start position:0% +Okay, so this was uh not Q implies not P + + + align:start position:0% +Okay, so this was uh not Q implies not P +is the same thing as this is the same + + align:start position:0% +is the same thing as this is the same + + + align:start position:0% +is the same thing as this is the same +thing as this and that is exactly this + + align:start position:0% +thing as this and that is exactly this + + + align:start position:0% +thing as this and that is exactly this +uh just by switching the order of the + + align:start position:0% +uh just by switching the order of the + + + align:start position:0% +uh just by switching the order of the +ors and so P implies Q is the same thing + + align:start position:0% +ors and so P implies Q is the same thing + + + align:start position:0% +ors and so P implies Q is the same thing +as not Q implies not P uh more uh so + + align:start position:0% +as not Q implies not P uh more uh so + + + align:start position:0% +as not Q implies not P uh more uh so +that was contraositive there's a related + + align:start position:0% +that was contraositive there's a related + + + align:start position:0% +that was contraositive there's a related +notion of contradiction where if you + + align:start position:0% +notion of contradiction where if you + + + align:start position:0% +notion of contradiction where if you +want to prove any statement P um you + + align:start position:0% +want to prove any statement P um you + + + align:start position:0% +want to prove any statement P um you +assume that not P is true and then find + + align:start position:0% +assume that not P is true and then find + + + align:start position:0% +assume that not P is true and then find +a contradiction prove that in fact false + + align:start position:0% +a contradiction prove that in fact false + + + align:start position:0% +a contradiction prove that in fact false +is true or something is both true and + + align:start position:0% +is true or something is both true and + + + align:start position:0% +is true or something is both true and +false. All these things are very very + + align:start position:0% +false. All these things are very very + + + align:start position:0% +false. All these things are very very +bad because we assume that our axioms + + align:start position:0% +bad because we assume that our axioms + + + align:start position:0% +bad because we assume that our axioms +are consistent. And so if you can prove + + align:start position:0% +are consistent. And so if you can prove + + + align:start position:0% +are consistent. And so if you can prove +false that means that what you assumed + + align:start position:0% +false that means that what you assumed + + + align:start position:0% +false that means that what you assumed +must also be false. + + align:start position:0% +must also be false. + + + align:start position:0% +must also be false. +Uh and if so if not P is false that's + + align:start position:0% +Uh and if so if not P is false that's + + + align:start position:0% +Uh and if so if not P is false that's +the same thing as saying P is true. + + align:start position:0% +the same thing as saying P is true. + + + align:start position:0% +the same thing as saying P is true. +Feels very backwards. Lots of double + + align:start position:0% +Feels very backwards. Lots of double + + + align:start position:0% +Feels very backwards. Lots of double +negatives in there but that's the nature + + align:start position:0% +negatives in there but that's the nature + + + align:start position:0% +negatives in there but that's the nature +of contradiction. We try to avoid them + + align:start position:0% +of contradiction. We try to avoid them + + + align:start position:0% +of contradiction. We try to avoid them +when we can but sometimes it's really + + align:start position:0% +when we can but sometimes it's really + + + align:start position:0% +when we can but sometimes it's really +the right way to prove something. And + + align:start position:0% +the right way to prove something. And + + + align:start position:0% +the right way to prove something. And +the last technique we saw was induction. + + align:start position:0% +the last technique we saw was induction. + + + align:start position:0% +the last technique we saw was induction. +uh where if we have a universal + + align:start position:0% +uh where if we have a universal + + + align:start position:0% +uh where if we have a universal +quantifier over the natural numbers, we + + align:start position:0% +quantifier over the natural numbers, we + + + align:start position:0% +quantifier over the natural numbers, we +want to prove P of N is true for all + + align:start position:0% +want to prove P of N is true for all + + + align:start position:0% +want to prove P of N is true for all +natural numbers 0 1 2 3 and so on. Uh + + align:start position:0% +natural numbers 0 1 2 3 and so on. Uh + + + align:start position:0% +natural numbers 0 1 2 3 and so on. Uh +then we only need to prove it for some + + align:start position:0% +then we only need to prove it for some + + + align:start position:0% +then we only need to prove it for some +base case P of 0 and then we need to + + align:start position:0% +base case P of 0 and then we need to + + + align:start position:0% +base case P of 0 and then we need to +prove that P of N implies P of N plus + + align:start position:0% +prove that P of N implies P of N plus + + + align:start position:0% +prove that P of N implies P of N plus +one for all N. So we'll talk more about + + align:start position:0% +one for all N. So we'll talk more about + + + align:start position:0% +one for all N. So we'll talk more about +induction in a little bit. Uh + + align:start position:0% +induction in a little bit. Uh + + + align:start position:0% +induction in a little bit. Uh +today we're going to add to this list + + align:start position:0% +today we're going to add to this list + + + align:start position:0% +today we're going to add to this list +two more proof techniques. One is proof + + align:start position:0% +two more proof techniques. One is proof + + + align:start position:0% +two more proof techniques. One is proof +by cases and the other is strong + + align:start position:0% +by cases and the other is strong + + + align:start position:0% +by cases and the other is strong +induction. So proof by cases is just a + + align:start position:0% +induction. So proof by cases is just a + + + align:start position:0% +induction. So proof by cases is just a +nice general technique to be aware of. + + align:start position:0% +nice general technique to be aware of. + + + align:start position:0% +nice general technique to be aware of. +Uh it's can be very powerful. Strong + + align:start position:0% +Uh it's can be very powerful. Strong + + + align:start position:0% +Uh it's can be very powerful. Strong +induction is going to be an even cooler + + align:start position:0% +induction is going to be an even cooler + + + align:start position:0% +induction is going to be an even cooler +form of induction. + + align:start position:0% +form of induction. + + + align:start position:0% +form of induction. +All right. But we'll start today with + + align:start position:0% +All right. But we'll start today with + + + align:start position:0% +All right. But we'll start today with +proof by cases. And we'll start with + + align:start position:0% +proof by cases. And we'll start with + + + align:start position:0% +proof by cases. And we'll start with +proof by two cases. + + align:start position:0% + + + + align:start position:0% + +and then we'll generalize to more than + + align:start position:0% +and then we'll generalize to more than + + + align:start position:0% +and then we'll generalize to more than +two cases. + + align:start position:0% + + + + align:start position:0% + +So, uh the idea is take any proposition + + align:start position:0% +So, uh the idea is take any proposition + + + align:start position:0% +So, uh the idea is take any proposition +C + + align:start position:0% + + + + align:start position:0% + +and observe that C or not C is a + + align:start position:0% +and observe that C or not C is a + + + align:start position:0% +and observe that C or not C is a +tautology + + align:start position:0% + + + + align:start position:0% + +meaning uh always true. + + align:start position:0% + + + + align:start position:0% + +Okay, if C is true, then this whole + + align:start position:0% +Okay, if C is true, then this whole + + + align:start position:0% +Okay, if C is true, then this whole +thing is true because C is true. If C is + + align:start position:0% +thing is true because C is true. If C is + + + align:start position:0% +thing is true because C is true. If C is +false, then not C is true. And so this + + align:start position:0% +false, then not C is true. And so this + + + align:start position:0% +false, then not C is true. And so this +whole thing is true. I'm going to remind + + align:start position:0% +whole thing is true. I'm going to remind + + + align:start position:0% +whole thing is true. I'm going to remind +you uh this uh so V symbol is an or. + + align:start position:0% +you uh this uh so V symbol is an or. + + + align:start position:0% +you uh this uh so V symbol is an or. +Uh whereas the opposite symbol is an + + align:start position:0% +Uh whereas the opposite symbol is an + + + align:start position:0% +Uh whereas the opposite symbol is an +and. + + align:start position:0% +and. + + + align:start position:0% +and. +I think the pneumonic here is this looks + + align:start position:0% +I think the pneumonic here is this looks + + + align:start position:0% +I think the pneumonic here is this looks +like a letter A. This looks like a + + align:start position:0% +like a letter A. This looks like a + + + align:start position:0% +like a letter A. This looks like a +letter O. I've heard some people say + + align:start position:0% +letter O. I've heard some people say + + + align:start position:0% +letter O. I've heard some people say +this looks like a lowercase R for or. Um + + align:start position:0% +this looks like a lowercase R for or. Um + + + align:start position:0% +this looks like a lowercase R for or. Um +anyway, you just remember these things. + + align:start position:0% +anyway, you just remember these things. + + + align:start position:0% +anyway, you just remember these things. +This is or this is and uh so C or not C + + align:start position:0% +This is or this is and uh so C or not C + + + align:start position:0% +This is or this is and uh so C or not C +is the question no is always true. Uh so + + align:start position:0% +is the question no is always true. Uh so + + + align:start position:0% +is the question no is always true. Uh so +we call it a tautology fancy word for + + align:start position:0% +we call it a tautology fancy word for + + + align:start position:0% +we call it a tautology fancy word for +being always true. And so uh + + align:start position:0% +being always true. And so uh + + + align:start position:0% +being always true. And so uh +what this tells us is that our + + align:start position:0% +what this tells us is that our + + + align:start position:0% +what this tells us is that our +proposition P let's say we want to prove + + align:start position:0% +proposition P let's say we want to prove + + + align:start position:0% +proposition P let's say we want to prove +P is equivalent to + + align:start position:0% + + + + align:start position:0% + +uh C or not C + + align:start position:0% +uh C or not C + + + align:start position:0% +uh C or not C +implies P. + + align:start position:0% +implies P. + + + align:start position:0% +implies P. +So this is saying if C or not C then P + + align:start position:0% +So this is saying if C or not C then P + + + align:start position:0% +So this is saying if C or not C then P +is true. C or not C is just always true. + + align:start position:0% +is true. C or not C is just always true. + + + align:start position:0% +is true. C or not C is just always true. +So this is saying if true in other words + + align:start position:0% +So this is saying if true in other words + + + align:start position:0% +So this is saying if true in other words +always P better be true. So P and this + + align:start position:0% +always P better be true. So P and this + + + align:start position:0% +always P better be true. So P and this +implication are equivalent. Another way + + align:start position:0% +implication are equivalent. Another way + + + align:start position:0% +implication are equivalent. Another way +to see that is to rewrite this + + align:start position:0% +to see that is to rewrite this + + + align:start position:0% +to see that is to rewrite this +implication as uh a negation I guess. So + + align:start position:0% +implication as uh a negation I guess. So + + + align:start position:0% +implication as uh a negation I guess. So +this is like saying not uh true + + align:start position:0% +this is like saying not uh true + + + align:start position:0% +this is like saying not uh true +or P and so that's just the same thing + + align:start position:0% +or P and so that's just the same thing + + + align:start position:0% +or P and so that's just the same thing +as P + + align:start position:0% +as P + + + align:start position:0% +as P +because this is true. + + align:start position:0% +because this is true. + + + align:start position:0% +because this is true. +Okay, cool. Uh so I want to rewrite this + + align:start position:0% +Okay, cool. Uh so I want to rewrite this + + + align:start position:0% +Okay, cool. Uh so I want to rewrite this +a little bit and say this thing is + + align:start position:0% +a little bit and say this thing is + + + align:start position:0% +a little bit and say this thing is +equivalent to C implies P and not C + + align:start position:0% +equivalent to C implies P and not C + + + align:start position:0% +equivalent to C implies P and not C +implies P. + + align:start position:0% + + + + align:start position:0% + +Uh why is this true? Uh it's like a + + align:start position:0% +Uh why is this true? Uh it's like a + + + align:start position:0% +Uh why is this true? Uh it's like a +distributive law. This is saying I want + + align:start position:0% +distributive law. This is saying I want + + + align:start position:0% +distributive law. This is saying I want +to prove that C implies P and I want to + + align:start position:0% +to prove that C implies P and I want to + + + align:start position:0% +to prove that C implies P and I want to +prove that not C implies P. That's what + + align:start position:0% +prove that not C implies P. That's what + + + align:start position:0% +prove that not C implies P. That's what +I wrote over there. Uh that implies that + + align:start position:0% +I wrote over there. Uh that implies that + + + align:start position:0% +I wrote over there. Uh that implies that +the combination of C and not C implies + + align:start position:0% +the combination of C and not C implies + + + align:start position:0% +the combination of C and not C implies +P. + + align:start position:0% +P. + + + align:start position:0% +P. +Okay. So I claim these are equivalent. + + align:start position:0% +Okay. So I claim these are equivalent. + + + align:start position:0% +Okay. So I claim these are equivalent. +You could one way to verify it is with + + align:start position:0% +You could one way to verify it is with + + + align:start position:0% +You could one way to verify it is with +the truth table or you can do it with + + align:start position:0% +the truth table or you can do it with + + + align:start position:0% +the truth table or you can do it with +some manipulation. + + align:start position:0% +some manipulation. + + + align:start position:0% +some manipulation. +All right. So uh we have + + align:start position:0% +All right. So uh we have + + + align:start position:0% +All right. So uh we have +uh what this is saying is in order to + + align:start position:0% +uh what this is saying is in order to + + + align:start position:0% +uh what this is saying is in order to +prove P we need to prove that P is true + + align:start position:0% +prove P we need to prove that P is true + + + align:start position:0% +prove P we need to prove that P is true +assuming C and prove that P is true + + align:start position:0% +assuming C and prove that P is true + + + align:start position:0% +assuming C and prove that P is true +assuming not C. And these are the two + + align:start position:0% +assuming not C. And these are the two + + + align:start position:0% +assuming not C. And these are the two +cases and proof by cases. Let me write + + align:start position:0% +cases and proof by cases. Let me write + + + align:start position:0% +cases and proof by cases. Let me write +out a little template for you. + + align:start position:0% + + + + align:start position:0% + +Let's suppose the theorem we want to + + align:start position:0% +Let's suppose the theorem we want to + + + align:start position:0% +Let's suppose the theorem we want to +prove + + align:start position:0% +prove + + + align:start position:0% +prove +is P. + + align:start position:0% + + + + align:start position:0% + +Theorem means something that's true and + + align:start position:0% +Theorem means something that's true and + + + align:start position:0% +Theorem means something that's true and +that we're about to prove. + + align:start position:0% +that we're about to prove. + + + align:start position:0% +that we're about to prove. +Uh and so we'd usually say proof by + + align:start position:0% +Uh and so we'd usually say proof by + + + align:start position:0% +Uh and so we'd usually say proof by +cases + + align:start position:0% +cases + + + align:start position:0% +cases +on the truth value + + align:start position:0% + + + + align:start position:0% + +of C. So this is uh for any + + align:start position:0% +of C. So this is uh for any + + + align:start position:0% +of C. So this is uh for any +uh + + align:start position:0% + + + + align:start position:0% + +statement seek + + align:start position:0% +statement seek + + + align:start position:0% +statement seek +proposition is what the word I was + + align:start position:0% +proposition is what the word I was + + + align:start position:0% +proposition is what the word I was +looking for. Any proposition C, it's + + align:start position:0% +looking for. Any proposition C, it's + + + align:start position:0% +looking for. Any proposition C, it's +either true or false. + + align:start position:0% + + + + align:start position:0% + +Uh and so we're going to do proof by + + align:start position:0% +Uh and so we're going to do proof by + + + align:start position:0% +Uh and so we're going to do proof by +cases on the truth value of C. Case one + + align:start position:0% +cases on the truth value of C. Case one + + + align:start position:0% +cases on the truth value of C. Case one +is that C is true + + align:start position:0% +is that C is true + + + align:start position:0% +is that C is true +and case two is that C is false. + + align:start position:0% + + + + align:start position:0% + +And so what do we do in each case? Uh + + align:start position:0% +And so what do we do in each case? Uh + + + align:start position:0% +And so what do we do in each case? Uh +well in the case that C is true this + + align:start position:0% +well in the case that C is true this + + + align:start position:0% +well in the case that C is true this +means that we get to assume that C is + + align:start position:0% +means that we get to assume that C is + + + align:start position:0% +means that we get to assume that C is +true + + align:start position:0% + + + + align:start position:0% + +uh and then use that to prove that P is + + align:start position:0% +uh and then use that to prove that P is + + + align:start position:0% +uh and then use that to prove that P is +true. And so the the missing step in + + align:start position:0% +true. And so the the missing step in + + + align:start position:0% +true. And so the the missing step in +this uh proof outline or this template + + align:start position:0% +this uh proof outline or this template + + + align:start position:0% +this uh proof outline or this template +uh is we need to say P is true because + + align:start position:0% +uh is we need to say P is true because + + + align:start position:0% +uh is we need to say P is true because +some reasons which we need to fill in. + + align:start position:0% +some reasons which we need to fill in. + + + align:start position:0% +some reasons which we need to fill in. +uh and similarly in the else in the C is + + align:start position:0% +uh and similarly in the else in the C is + + + align:start position:0% +uh and similarly in the else in the C is +false case we need to prove P is true + + align:start position:0% +false case we need to prove P is true + + + align:start position:0% +false case we need to prove P is true +uh + + align:start position:0% +uh + + + align:start position:0% +uh +for some reasons. Okay, so we need twice + + align:start position:0% +for some reasons. Okay, so we need twice + + + align:start position:0% +for some reasons. Okay, so we need twice +as many reasons but the idea is that + + align:start position:0% +as many reasons but the idea is that + + + align:start position:0% +as many reasons but the idea is that +maybe assuming C is true makes it easier + + align:start position:0% +maybe assuming C is true makes it easier + + + align:start position:0% +maybe assuming C is true makes it easier +to prove P is true. Maybe also proving + + align:start position:0% +to prove P is true. Maybe also proving + + + align:start position:0% +to prove P is true. Maybe also proving +assuming C is false makes it easier to + + align:start position:0% +assuming C is false makes it easier to + + + align:start position:0% +assuming C is false makes it easier to +to prove that P is true. So in these + + align:start position:0% +to prove that P is true. So in these + + + align:start position:0% +to prove that P is true. So in these +boxes here we get to use C and in here + + align:start position:0% +boxes here we get to use C and in here + + + align:start position:0% +boxes here we get to use C and in here +we get to use not C. And often this + + align:start position:0% +we get to use not C. And often this + + + align:start position:0% +we get to use not C. And often this +makes proofs easier. But the challenging + + align:start position:0% +makes proofs easier. But the challenging + + + align:start position:0% +makes proofs easier. But the challenging +part is to pick the correct C. What's + + align:start position:0% +part is to pick the correct C. What's + + + align:start position:0% +part is to pick the correct C. What's +the right choice of C for this to be + + align:start position:0% +the right choice of C for this to be + + + align:start position:0% +the right choice of C for this to be +true. Um, and maybe one more line I want + + align:start position:0% +true. Um, and maybe one more line I want + + + align:start position:0% +true. Um, and maybe one more line I want +to add to this template, which is pretty + + align:start position:0% +to add to this template, which is pretty + + + align:start position:0% +to add to this template, which is pretty +obvious in this setting, but gets much + + align:start position:0% +obvious in this setting, but gets much + + + align:start position:0% +obvious in this setting, but gets much +less obvious when you think about more + + align:start position:0% +less obvious when you think about more + + + align:start position:0% +less obvious when you think about more +than two cases. So a final step in this + + align:start position:0% +than two cases. So a final step in this + + + align:start position:0% +than two cases. So a final step in this +proof would be to say uh C is either + + align:start position:0% +proof would be to say uh C is either + + + align:start position:0% +proof would be to say uh C is either +true or false because all propositions + + align:start position:0% +true or false because all propositions + + + align:start position:0% +true or false because all propositions +are either true or false. + + align:start position:0% +are either true or false. + + + align:start position:0% +are either true or false. +And so uh the cases are exhaustive. + + align:start position:0% +And so uh the cases are exhaustive. + + + align:start position:0% +And so uh the cases are exhaustive. +So this is also called a proof by + + align:start position:0% +So this is also called a proof by + + + align:start position:0% +So this is also called a proof by +exhaustion. Not because we're really + + align:start position:0% +exhaustion. Not because we're really + + + align:start position:0% +exhaustion. Not because we're really +tired, maybe we are also. But the idea + + align:start position:0% +tired, maybe we are also. But the idea + + + align:start position:0% +tired, maybe we are also. But the idea +is we want to exhaust all possible + + align:start position:0% +is we want to exhaust all possible + + + align:start position:0% +is we want to exhaust all possible +cases. And if we prove that we we + + align:start position:0% +cases. And if we prove that we we + + + align:start position:0% +cases. And if we prove that we we +captured every possible situation and + + align:start position:0% +captured every possible situation and + + + align:start position:0% +captured every possible situation and +all of them P is true then we're done. + + align:start position:0% +all of them P is true then we're done. + + + align:start position:0% +all of them P is true then we're done. +Okay. So that's what we'd like to do. + + align:start position:0% +Okay. So that's what we'd like to do. + + + align:start position:0% +Okay. So that's what we'd like to do. +I'm going to give you two examples. + + align:start position:0% +I'm going to give you two examples. + + + align:start position:0% +I'm going to give you two examples. +First one is very simple. The second one + + align:start position:0% +First one is very simple. The second one + + + align:start position:0% +First one is very simple. The second one +is more interesting + + align:start position:0% + + + + align:start position:0% + +questions. All right. Um, + + align:start position:0% + + + + align:start position:0% + +so the claim is this is a general fact + + align:start position:0% +so the claim is this is a general fact + + + align:start position:0% +so the claim is this is a general fact +that a implies b or b implies c is a + + align:start position:0% +that a implies b or b implies c is a + + + align:start position:0% +that a implies b or b implies c is a +tautology. So this means it's always + + align:start position:0% +tautology. So this means it's always + + + align:start position:0% +tautology. So this means it's always +true again. So you can rewrite this as + + align:start position:0% +true again. So you can rewrite this as + + + align:start position:0% +true again. So you can rewrite this as +for all a, b and c uh which are either + + align:start position:0% +for all a, b and c uh which are either + + + align:start position:0% +for all a, b and c uh which are either +true or false + + align:start position:0% + + + + align:start position:0% + +uh we have that a implies b or b implies + + align:start position:0% +uh we have that a implies b or b implies + + + align:start position:0% +uh we have that a implies b or b implies +c is true. + + align:start position:0% + + + + align:start position:0% + +Okay, fun fun fact. Um let's prove it. + + align:start position:0% +Okay, fun fun fact. Um let's prove it. + + + align:start position:0% +Okay, fun fun fact. Um let's prove it. +And the proof technique we're going to + + align:start position:0% +And the proof technique we're going to + + + align:start position:0% +And the proof technique we're going to +use by cases by two cases namely uh on B + + align:start position:0% +use by cases by two cases namely uh on B + + + align:start position:0% +use by cases by two cases namely uh on B +B is either true or false. + + align:start position:0% + + + + align:start position:0% + +We could try to do a case analysis in + + align:start position:0% +We could try to do a case analysis in + + + align:start position:0% +We could try to do a case analysis in +terms of A or in terms of C. Turns out B + + align:start position:0% +terms of A or in terms of C. Turns out B + + + align:start position:0% +terms of A or in terms of C. Turns out B +is sort of the right answer here. It + + align:start position:0% +is sort of the right answer here. It + + + align:start position:0% +is sort of the right answer here. It +will lead to the fewest cases. We'll + + align:start position:0% +will lead to the fewest cases. We'll + + + align:start position:0% +will lead to the fewest cases. We'll +only need two uh intuitively because B + + align:start position:0% +only need two uh intuitively because B + + + align:start position:0% +only need two uh intuitively because B +is in both of these expressions. So it + + align:start position:0% +is in both of these expressions. So it + + + align:start position:0% +is in both of these expressions. So it +seems good to split on B because it will + + align:start position:0% +seems good to split on B because it will + + + align:start position:0% +seems good to split on B because it will +impact this one and this one. + + align:start position:0% +impact this one and this one. + + + align:start position:0% +impact this one and this one. +Okay. Uh so + + align:start position:0% +Okay. Uh so + + + align:start position:0% +Okay. Uh so +case one + + align:start position:0% +case one + + + align:start position:0% +case one +is that B is true. + + align:start position:0% + + + + align:start position:0% + +Okay. + + align:start position:0% +Okay. + + + align:start position:0% +Okay. +uh if B is true, I claim that A implies + + align:start position:0% +uh if B is true, I claim that A implies + + + align:start position:0% +uh if B is true, I claim that A implies +B is true, + + align:start position:0% +B is true, + + + align:start position:0% +B is true, +which is this first half. + + align:start position:0% +which is this first half. + + + align:start position:0% +which is this first half. +Why? + + align:start position:0% +Why? + + + align:start position:0% +Why? +Uh in other words, I I claim that A + + align:start position:0% +Uh in other words, I I claim that A + + + align:start position:0% +Uh in other words, I I claim that A +implies true is a tautology. + + align:start position:0% +implies true is a tautology. + + + align:start position:0% +implies true is a tautology. +I think another again an easy way to see + + align:start position:0% +I think another again an easy way to see + + + align:start position:0% +I think another again an easy way to see +this is to rewrite uh rewrite this + + align:start position:0% +this is to rewrite uh rewrite this + + + align:start position:0% +this is to rewrite uh rewrite this +implication as not the left hand side or + + align:start position:0% +implication as not the left hand side or + + + align:start position:0% +implication as not the left hand side or +the right hand side. + + align:start position:0% +the right hand side. + + + align:start position:0% +the right hand side. +Right? Not a or true. Well, that's just + + align:start position:0% +Right? Not a or true. Well, that's just + + + align:start position:0% +Right? Not a or true. Well, that's just +true. True or anything is true. Okay? + + align:start position:0% +true. True or anything is true. Okay? + + + align:start position:0% +true. True or anything is true. Okay? +So, in particular over here, uh not a or + + align:start position:0% +So, in particular over here, uh not a or + + + align:start position:0% +So, in particular over here, uh not a or +b is true because we just assume that b + + align:start position:0% +b is true because we just assume that b + + + align:start position:0% +b is true because we just assume that b +is true. + + align:start position:0% +is true. + + + align:start position:0% +is true. +Okay. So, this tells us that uh a + + align:start position:0% +Okay. So, this tells us that uh a + + + align:start position:0% +Okay. So, this tells us that uh a +implies b or anything in particular b or + + align:start position:0% +implies b or anything in particular b or + + + align:start position:0% +implies b or anything in particular b or +c is also true. + + align:start position:0% +c is also true. + + + align:start position:0% +c is also true. +Okay. So, kind of trivial, right? Right? + + align:start position:0% +Okay. So, kind of trivial, right? Right? + + + align:start position:0% +Okay. So, kind of trivial, right? Right? +If you assume B is true, then of course + + align:start position:0% +If you assume B is true, then of course + + + align:start position:0% +If you assume B is true, then of course +this is true and so of course the whole + + align:start position:0% +this is true and so of course the whole + + + align:start position:0% +this is true and so of course the whole +thing is true. + + align:start position:0% +thing is true. + + + align:start position:0% +thing is true. +So easy when you have the correct case. + + align:start position:0% +So easy when you have the correct case. + + + align:start position:0% +So easy when you have the correct case. +Uh let's think about the other case. + + align:start position:0% +Uh let's think about the other case. + + + align:start position:0% +Uh let's think about the other case. +It's not enough to just have one half of + + align:start position:0% +It's not enough to just have one half of + + + align:start position:0% +It's not enough to just have one half of +the cases. We also need to think about + + align:start position:0% +the cases. We also need to think about + + + align:start position:0% +the cases. We also need to think about +when B is false. + + align:start position:0% + + + + align:start position:0% + +When B is false, I claim that the other + + align:start position:0% +When B is false, I claim that the other + + + align:start position:0% +When B is false, I claim that the other +term is true. I claim that B implies C + + align:start position:0% +term is true. I claim that B implies C + + + align:start position:0% +term is true. I claim that B implies C +is true. + + align:start position:0% +is true. + + + align:start position:0% +is true. +Uh this is maybe a little less + + align:start position:0% +Uh this is maybe a little less + + + align:start position:0% +Uh this is maybe a little less +intuitive. This is saying that false + + align:start position:0% +intuitive. This is saying that false + + + align:start position:0% +intuitive. This is saying that false +implies C is a tautology like for any C + + align:start position:0% +implies C is a tautology like for any C + + + align:start position:0% +implies C is a tautology like for any C +false implies it. Um and this should + + align:start position:0% +false implies it. Um and this should + + + align:start position:0% +false implies it. Um and this should +eventually become intuitive for you when + + align:start position:0% +eventually become intuitive for you when + + + align:start position:0% +eventually become intuitive for you when +you get used to implies and if then this + + align:start position:0% +you get used to implies and if then this + + + align:start position:0% +you get used to implies and if then this +is saying if false which means never uh + + align:start position:0% +is saying if false which means never uh + + + align:start position:0% +is saying if false which means never uh +I need C to be true. But if I if this + + align:start position:0% +I need C to be true. But if I if this + + + align:start position:0% +I need C to be true. But if I if this +condition is never true then I don't + + align:start position:0% +condition is never true then I don't + + + align:start position:0% +condition is never true then I don't +care about the right hand side. If it's + + align:start position:0% +care about the right hand side. If it's + + + align:start position:0% +care about the right hand side. If it's +if you know if uh pigs fly then I don't + + align:start position:0% +if you know if uh pigs fly then I don't + + + align:start position:0% +if you know if uh pigs fly then I don't +know apples are orange or something. Um + + align:start position:0% +know apples are orange or something. Um + + + align:start position:0% +know apples are orange or something. Um +it that's a true statement because it + + align:start position:0% +it that's a true statement because it + + + align:start position:0% +it that's a true statement because it +will never be the case that pigs fly at + + align:start position:0% +will never be the case that pigs fly at + + + align:start position:0% +will never be the case that pigs fly at +least in the present time. So uh another + + align:start position:0% +least in the present time. So uh another + + + align:start position:0% +least in the present time. So uh another +way to see that is to think about again + + align:start position:0% +way to see that is to think about again + + + align:start position:0% +way to see that is to think about again +not B or C. + + align:start position:0% +not B or C. + + + align:start position:0% +not B or C. +B is false so not B is true and so of + + align:start position:0% +B is false so not B is true and so of + + + align:start position:0% +B is false so not B is true and so of +course true or C is also true. + + align:start position:0% +course true or C is also true. + + + align:start position:0% +course true or C is also true. +Okay. And so that tells us that anything + + align:start position:0% +Okay. And so that tells us that anything + + + align:start position:0% +Okay. And so that tells us that anything +or B implies C is also true. + + align:start position:0% +or B implies C is also true. + + + align:start position:0% +or B implies C is also true. +So in other words, this statement + + align:start position:0% +So in other words, this statement + + + align:start position:0% +So in other words, this statement +maybe I'll call P, I'll say in either + + align:start position:0% +maybe I'll call P, I'll say in either + + + align:start position:0% +maybe I'll call P, I'll say in either +case + + align:start position:0% + + + + align:start position:0% + +P is true. And so I write my little end + + align:start position:0% +P is true. And so I write my little end + + + align:start position:0% +P is true. And so I write my little end +of crew symbol. This is QED from last + + align:start position:0% +of crew symbol. This is QED from last + + + align:start position:0% +of crew symbol. This is QED from last +time. Uh this means that I have + + align:start position:0% +time. Uh this means that I have + + + align:start position:0% +time. Uh this means that I have +demonstrated the theorem. + + align:start position:0% + + + + align:start position:0% + +Cool. So in one case this part was + + align:start position:0% +Cool. So in one case this part was + + + align:start position:0% +Cool. So in one case this part was +trivial. In the other case this part was + + align:start position:0% +trivial. In the other case this part was + + + align:start position:0% +trivial. In the other case this part was +trivial because it's an or. We're happy + + align:start position:0% +trivial because it's an or. We're happy + + + align:start position:0% +trivial because it's an or. We're happy +in either case. And we've done our proof + + align:start position:0% +in either case. And we've done our proof + + + align:start position:0% +in either case. And we've done our proof +first proof by cases. Pretty + + align:start position:0% +first proof by cases. Pretty + + + align:start position:0% +first proof by cases. Pretty +straightforward. + + align:start position:0% +straightforward. + + + align:start position:0% +straightforward. +Let's do a more surprising result + + align:start position:0% +Let's do a more surprising result + + + align:start position:0% +Let's do a more surprising result +using proof by cases called + + align:start position:0% +using proof by cases called + + + align:start position:0% +using proof by cases called +mutual + + align:start position:0% +mutual + + + align:start position:0% +mutual +friends and strangers. + + align:start position:0% + + + + align:start position:0% + +This is actually a famous mathematical + + align:start position:0% +This is actually a famous mathematical + + + align:start position:0% +This is actually a famous mathematical +problem we're going to solve today a + + align:start position:0% +problem we're going to solve today a + + + align:start position:0% +problem we're going to solve today a +particular case of it + + align:start position:0% +particular case of it + + + align:start position:0% +particular case of it +which is suppose you have six people + + align:start position:0% + + + + align:start position:0% + +um and every two of them are either + + align:start position:0% +um and every two of them are either + + + align:start position:0% +um and every two of them are either +friends or + + align:start position:0% + + + + align:start position:0% + +uh and this is an exclusive or so. So + + align:start position:0% +uh and this is an exclusive or so. So + + + align:start position:0% +uh and this is an exclusive or so. So +I'm going to write exor. You're allowed + + align:start position:0% +I'm going to write exor. You're allowed + + + align:start position:0% +I'm going to write exor. You're allowed +to be friends or or not friends, not + + align:start position:0% +to be friends or or not friends, not + + + align:start position:0% +to be friends or or not friends, not +both and not neither. And in the not + + align:start position:0% +both and not neither. And in the not + + + align:start position:0% +both and not neither. And in the not +friends case, I'm also going to call + + align:start position:0% +friends case, I'm also going to call + + + align:start position:0% +friends case, I'm also going to call +them uh strangers. + + align:start position:0% +them uh strangers. + + + align:start position:0% +them uh strangers. +So this is like extreme friendship. + + align:start position:0% +So this is like extreme friendship. + + + align:start position:0% +So this is like extreme friendship. +Either you declare yourself as friends + + align:start position:0% +Either you declare yourself as friends + + + align:start position:0% +Either you declare yourself as friends +or as knowing each other or you don't + + align:start position:0% +or as knowing each other or you don't + + + align:start position:0% +or as knowing each other or you don't +know each other. In that case, you're + + align:start position:0% +know each other. In that case, you're + + + align:start position:0% +know each other. In that case, you're +strangers. You're just never both. It's + + align:start position:0% +strangers. You're just never both. It's + + + align:start position:0% +strangers. You're just never both. It's +always one or the other. Okay? So, you + + align:start position:0% +always one or the other. Okay? So, you + + + align:start position:0% +always one or the other. Okay? So, you +can think of this as I can draw a little + + align:start position:0% +can think of this as I can draw a little + + + align:start position:0% +can think of this as I can draw a little +picture of their six people represent by + + align:start position:0% +picture of their six people represent by + + + align:start position:0% +picture of their six people represent by +circles. You can put smiley faces in + + align:start position:0% +circles. You can put smiley faces in + + + align:start position:0% +circles. You can put smiley faces in +them if you want. And maybe I connect + + align:start position:0% +them if you want. And maybe I connect + + + align:start position:0% +them if you want. And maybe I connect +them via a white line if they are + + align:start position:0% +them via a white line if they are + + + align:start position:0% +them via a white line if they are +friends and a dotted line if they're + + align:start position:0% +friends and a dotted line if they're + + + align:start position:0% +friends and a dotted line if they're +strangers. So let's And every two of + + align:start position:0% +strangers. So let's And every two of + + + align:start position:0% +strangers. So let's And every two of +them have one of these two pictures. + + align:start position:0% + + + + align:start position:0% + +Probably missing some + + align:start position:0% +Probably missing some + + + align:start position:0% +Probably missing some +here. + + align:start position:0% +here. + + + align:start position:0% +here. +That's them all. Uh then + + align:start position:0% +That's them all. Uh then + + + align:start position:0% +That's them all. Uh then +I claim + + align:start position:0% + + + + align:start position:0% + +no matter how what the situation is, + + align:start position:0% +no matter how what the situation is, + + + align:start position:0% +no matter how what the situation is, +which ones are friends, which ones are + + align:start position:0% +which ones are friends, which ones are + + + align:start position:0% +which ones are friends, which ones are +strangers, there's always + + align:start position:0% +strangers, there's always + + + align:start position:0% +strangers, there's always +uh either + + align:start position:0% + + + + align:start position:0% + +three mutual friends + + align:start position:0% + + + + align:start position:0% + +for + + align:start position:0% +for + + + align:start position:0% +for +three mutual strangers. + + align:start position:0% + + + + align:start position:0% + +Okay, in this example, + + align:start position:0% +Okay, in this example, + + + align:start position:0% +Okay, in this example, +hopefully I drew enough. Yeah. Uh, these + + align:start position:0% +hopefully I drew enough. Yeah. Uh, these + + + align:start position:0% +hopefully I drew enough. Yeah. Uh, these +three people are mutual strangers. + + align:start position:0% +three people are mutual strangers. + + + align:start position:0% +three people are mutual strangers. +They're connected by a a triangle of + + align:start position:0% +They're connected by a a triangle of + + + align:start position:0% +They're connected by a a triangle of +dashed lines. Okay. If I drew some other + + align:start position:0% +dashed lines. Okay. If I drew some other + + + align:start position:0% +dashed lines. Okay. If I drew some other +pattern, like if they were all solid + + align:start position:0% +pattern, like if they were all solid + + + align:start position:0% +pattern, like if they were all solid +lines, then uh I might get the other + + align:start position:0% +lines, then uh I might get the other + + + align:start position:0% +lines, then uh I might get the other +situation, at least three mutual + + align:start position:0% +situation, at least three mutual + + + align:start position:0% +situation, at least three mutual +friends. But it turns out if you have + + align:start position:0% +friends. But it turns out if you have + + + align:start position:0% +friends. But it turns out if you have +six people, they're always at least + + align:start position:0% +six people, they're always at least + + + align:start position:0% +six people, they're always at least +three mutual friends or three mutual + + align:start position:0% +three mutual friends or three mutual + + + align:start position:0% +three mutual friends or three mutual +strangers. Let's prove this by cases. + + align:start position:0% + + + + align:start position:0% + +Whenever we apply a proof by cases, we + + align:start position:0% +Whenever we apply a proof by cases, we + + + align:start position:0% +Whenever we apply a proof by cases, we +need to come up with some proposition C + + align:start position:0% +need to come up with some proposition C + + + align:start position:0% +need to come up with some proposition C +that's either true or false. Well, for a + + align:start position:0% +that's either true or false. Well, for a + + + align:start position:0% +that's either true or false. Well, for a +proof by two cases, which this will be + + align:start position:0% +proof by two cases, which this will be + + + align:start position:0% +proof by two cases, which this will be +uh and it's a little work in this case + + align:start position:0% +uh and it's a little work in this case + + + align:start position:0% +uh and it's a little work in this case +to to do it. It turns out a useful first + + align:start position:0% +to to do it. It turns out a useful first + + + align:start position:0% +to to do it. It turns out a useful first +step is to pick any person P. + + align:start position:0% + + + + align:start position:0% + +So just take the first person or the + + align:start position:0% +So just take the first person or the + + + align:start position:0% +So just take the first person or the +seventh or the the fifth person ahead of + + align:start position:0% +seventh or the the fifth person ahead of + + + align:start position:0% +seventh or the the fifth person ahead of +six doesn't matter which one but label + + align:start position:0% +six doesn't matter which one but label + + + align:start position:0% +six doesn't matter which one but label +it P. So now we have a person to talk + + align:start position:0% +it P. So now we have a person to talk + + + align:start position:0% +it P. So now we have a person to talk +about. This is sort of like the proof by + + align:start position:0% +about. This is sort of like the proof by + + + align:start position:0% +about. This is sort of like the proof by +example or by construction right we want + + align:start position:0% +example or by construction right we want + + + align:start position:0% +example or by construction right we want +to overall there we want to prove an + + align:start position:0% +to overall there we want to prove an + + + align:start position:0% +to overall there we want to prove an +existence we want to prove existence of + + align:start position:0% +existence we want to prove existence of + + + align:start position:0% +existence we want to prove existence of +three mutual friends or existence of + + align:start position:0% +three mutual friends or existence of + + + align:start position:0% +three mutual friends or existence of +three mutual strangers. So it's a useful + + align:start position:0% +three mutual strangers. So it's a useful + + + align:start position:0% +three mutual strangers. So it's a useful +step to either construct one or in this + + align:start position:0% +step to either construct one or in this + + + align:start position:0% +step to either construct one or in this +case we're actually not doing much of a + + align:start position:0% +case we're actually not doing much of a + + + align:start position:0% +case we're actually not doing much of a +construction. We're just taking an + + align:start position:0% +construction. We're just taking an + + + align:start position:0% +construction. We're just taking an +arbitrary X, but that will be enough for + + align:start position:0% +arbitrary X, but that will be enough for + + + align:start position:0% +arbitrary X, but that will be enough for +this for this problem. Okay, so let me + + align:start position:0% +this for this problem. Okay, so let me + + + align:start position:0% +this for this problem. Okay, so let me +draw a little circle for P. + + align:start position:0% +draw a little circle for P. + + + align:start position:0% +draw a little circle for P. +Uh, and it might have some friends and + + align:start position:0% +Uh, and it might have some friends and + + + align:start position:0% +Uh, and it might have some friends and +it might have some strangers. Okay, how + + align:start position:0% +it might have some strangers. Okay, how + + + align:start position:0% +it might have some strangers. Okay, how +many of these lines coming out of P are + + align:start position:0% +many of these lines coming out of P are + + + align:start position:0% +many of these lines coming out of P are +there? Five. Exactly. Because there's + + align:start position:0% +there? Five. Exactly. Because there's + + + align:start position:0% +there? Five. Exactly. Because there's +six people total. P is one of them. So + + align:start position:0% +six people total. P is one of them. So + + + align:start position:0% +six people total. P is one of them. So +there are five people over here. + + align:start position:0% +there are five people over here. + + + align:start position:0% +there are five people over here. +Okay, so turns out useful case strategy + + align:start position:0% +Okay, so turns out useful case strategy + + + align:start position:0% +Okay, so turns out useful case strategy +is to uh say either P has at least three + + align:start position:0% +is to uh say either P has at least three + + + align:start position:0% +is to uh say either P has at least three +friends + + align:start position:0% +friends + + + align:start position:0% +friends +or it has less than three friends, + + align:start position:0% +or it has less than three friends, + + + align:start position:0% +or it has less than three friends, +right? Either there are three solid + + align:start position:0% +right? Either there are three solid + + + align:start position:0% +right? Either there are three solid +lines like I've drawn here or there at + + align:start position:0% +lines like I've drawn here or there at + + + align:start position:0% +lines like I've drawn here or there at +least three or they're at most two solid + + align:start position:0% +least three or they're at most two solid + + + align:start position:0% +least three or they're at most two solid +lines. Okay, let's think about this + + align:start position:0% +lines. Okay, let's think about this + + + align:start position:0% +lines. Okay, let's think about this +first case. P has at least three + + align:start position:0% +first case. P has at least three + + + align:start position:0% +first case. P has at least three +friends. Let's uh give them a name + + align:start position:0% +friends. Let's uh give them a name + + + align:start position:0% +friends. Let's uh give them a name +uh Q, R, and S. + + align:start position:0% +uh Q, R, and S. + + + align:start position:0% +uh Q, R, and S. +So uh that's sort of a general picture. + + align:start position:0% +So uh that's sort of a general picture. + + + align:start position:0% +So uh that's sort of a general picture. +Now we're assuming P has three solid + + align:start position:0% +Now we're assuming P has three solid + + + align:start position:0% +Now we're assuming P has three solid +lines to three people Q, R, and S. + + align:start position:0% +lines to three people Q, R, and S. + + + align:start position:0% +lines to three people Q, R, and S. +Okay, this is not yet a triangle. We + + align:start position:0% +Okay, this is not yet a triangle. We + + + align:start position:0% +Okay, this is not yet a triangle. We +haven't solved the problem yet, but uh + + align:start position:0% +haven't solved the problem yet, but uh + + + align:start position:0% +haven't solved the problem yet, but uh +if we break into more cases, we'll be + + align:start position:0% +if we break into more cases, we'll be + + + align:start position:0% +if we break into more cases, we'll be +able to. Okay. So, uh case + + align:start position:0% +able to. Okay. So, uh case + + + align:start position:0% +able to. Okay. So, uh case +1 A is going to be + + align:start position:0% +1 A is going to be + + + align:start position:0% +1 A is going to be +uh sum two + + align:start position:0% +uh sum two + + + align:start position:0% +uh sum two +of Q, R and S are friends. + + align:start position:0% + + + + align:start position:0% + +Okay. Suppose + + align:start position:0% +Okay. Suppose + + + align:start position:0% +Okay. Suppose +uh for example Q and S are friends. Have + + align:start position:0% +uh for example Q and S are friends. Have + + + align:start position:0% +uh for example Q and S are friends. Have +I found a triangle? Yes. P Q and S are + + align:start position:0% +I found a triangle? Yes. P Q and S are + + + align:start position:0% +I found a triangle? Yes. P Q and S are +mutual friends. If this edge is here or + + align:start position:0% +mutual friends. If this edge is here or + + + align:start position:0% +mutual friends. If this edge is here or +if this edge is here then these three + + align:start position:0% +if this edge is here then these three + + + align:start position:0% +if this edge is here then these three +people are three mutual friends or if + + align:start position:0% +people are three mutual friends or if + + + align:start position:0% +people are three mutual friends or if +this edge is here these three people are + + align:start position:0% +this edge is here these three people are + + + align:start position:0% +this edge is here these three people are +mutual friends. If there's any edge in + + align:start position:0% +mutual friends. If there's any edge in + + + align:start position:0% +mutual friends. If there's any edge in +here that I can draw any uh solid line + + align:start position:0% +here that I can draw any uh solid line + + + align:start position:0% +here that I can draw any uh solid line +between QR and S then those two people + + align:start position:0% +between QR and S then those two people + + + align:start position:0% +between QR and S then those two people +plus P form three mutual friends. + + align:start position:0% +plus P form three mutual friends. + + + align:start position:0% +plus P form three mutual friends. +Okay. So that case is actually easy. + + align:start position:0% +Okay. So that case is actually easy. + + + align:start position:0% +Okay. So that case is actually easy. +Great. + + align:start position:0% +Great. + + + align:start position:0% +Great. +Then uh P plus those two people + + align:start position:0% +Then uh P plus those two people + + + align:start position:0% +Then uh P plus those two people +are three mutual friends. + + align:start position:0% + + + + align:start position:0% + +Okay, which uh was situation one up + + align:start position:0% +Okay, which uh was situation one up + + + align:start position:0% +Okay, which uh was situation one up +here. There's always either three mutual + + align:start position:0% +here. There's always either three mutual + + + align:start position:0% +here. There's always either three mutual +friends or three mutual strangers. + + align:start position:0% + + + + align:start position:0% + +Okay, uh so now we need to think about + + align:start position:0% +Okay, uh so now we need to think about + + + align:start position:0% +Okay, uh so now we need to think about +the other cases. Let's go over here. + + align:start position:0% +the other cases. Let's go over here. + + + align:start position:0% +the other cases. Let's go over here. +We found one case that was easy, but uh + + align:start position:0% +We found one case that was easy, but uh + + + align:start position:0% +We found one case that was easy, but uh +there's case 1B, which is maybe there + + align:start position:0% +there's case 1B, which is maybe there + + + align:start position:0% +there's case 1B, which is maybe there +aren't two mutual friends, and there's + + align:start position:0% +aren't two mutual friends, and there's + + + align:start position:0% +aren't two mutual friends, and there's +case two where P does not have at least + + align:start position:0% +case two where P does not have at least + + + align:start position:0% +case two where P does not have at least +three friends. Okay, but it turns out + + align:start position:0% +three friends. Okay, but it turns out + + + align:start position:0% +three friends. Okay, but it turns out +all of these cases will be easy. So, + + align:start position:0% +all of these cases will be easy. So, + + + align:start position:0% +all of these cases will be easy. So, +let's do uh case 1 B. + + align:start position:0% +let's do uh case 1 B. + + + align:start position:0% +let's do uh case 1 B. +Now, I get to sort of freely choose what + + align:start position:0% +Now, I get to sort of freely choose what + + + align:start position:0% +Now, I get to sort of freely choose what +case one was, and I get to freely choose + + align:start position:0% +case one was, and I get to freely choose + + + align:start position:0% +case one was, and I get to freely choose +what case 1 A was because whenever I + + align:start position:0% +what case 1 A was because whenever I + + + align:start position:0% +what case 1 A was because whenever I +split into cases, I get to choose my + + align:start position:0% +split into cases, I get to choose my + + + align:start position:0% +split into cases, I get to choose my +proposition C to be anything I want. So + + align:start position:0% +proposition C to be anything I want. So + + + align:start position:0% +proposition C to be anything I want. So +this was C in the first case. This was C + + align:start position:0% +this was C in the first case. This was C + + + align:start position:0% +this was C in the first case. This was C +in the second case. But generally if + + align:start position:0% +in the second case. But generally if + + + align:start position:0% +in the second case. But generally if +you're doing proof by two cases, you + + align:start position:0% +you're doing proof by two cases, you + + + align:start position:0% +you're doing proof by two cases, you +have no choice at this point. So case 1 + + align:start position:0% +have no choice at this point. So case 1 + + + align:start position:0% +have no choice at this point. So case 1 +A was whatever. Case 1 B has to be the + + align:start position:0% +A was whatever. Case 1 B has to be the + + + align:start position:0% +A was whatever. Case 1 B has to be the +negation of this. + + align:start position:0% +negation of this. + + + align:start position:0% +negation of this. +Okay. So case 1B literally is uh not sum + + align:start position:0% +Okay. So case 1B literally is uh not sum + + + align:start position:0% +Okay. So case 1B literally is uh not sum +to uh of QRS are friends. Uh but if you + + align:start position:0% +to uh of QRS are friends. Uh but if you + + + align:start position:0% +to uh of QRS are friends. Uh but if you +think about that for a little bit, this + + align:start position:0% +think about that for a little bit, this + + + align:start position:0% +think about that for a little bit, this +is saying um + + align:start position:0% + + + + align:start position:0% + +Q R and S uh let me let me write this uh + + align:start position:0% +Q R and S uh let me let me write this uh + + + align:start position:0% +Q R and S uh let me let me write this uh +in a couple of steps. No two of Q R and + + align:start position:0% +in a couple of steps. No two of Q R and + + + align:start position:0% +in a couple of steps. No two of Q R and +S are friends. + + align:start position:0% + + + + align:start position:0% + +But that's the same thing as saying QR + + align:start position:0% +But that's the same thing as saying QR + + + align:start position:0% +But that's the same thing as saying QR +and S are mutual strangers. + + align:start position:0% + + + + align:start position:0% + +Okay, we're using this fact or this + + align:start position:0% +Okay, we're using this fact or this + + + align:start position:0% +Okay, we're using this fact or this +assumption that every two people are + + align:start position:0% +assumption that every two people are + + + align:start position:0% +assumption that every two people are +either friends or strangers. + + align:start position:0% +either friends or strangers. + + + align:start position:0% +either friends or strangers. +Always one or the other. So if there's + + align:start position:0% +Always one or the other. So if there's + + + align:start position:0% +Always one or the other. So if there's +no solid line over here, then all of + + align:start position:0% +no solid line over here, then all of + + + align:start position:0% +no solid line over here, then all of +these are dash lines. So all three of + + align:start position:0% +these are dash lines. So all three of + + + align:start position:0% +these are dash lines. So all three of +these are mutual strangers. And there we + + align:start position:0% +these are mutual strangers. And there we + + + align:start position:0% +these are mutual strangers. And there we +found our triangle of strangers. + + align:start position:0% +found our triangle of strangers. + + + align:start position:0% +found our triangle of strangers. +Okay. So it turns out case 1 A and case + + align:start position:0% +Okay. So it turns out case 1 A and case + + + align:start position:0% +Okay. So it turns out case 1 A and case +1 B are actually just as easy, just sort + + align:start position:0% +1 B are actually just as easy, just sort + + + align:start position:0% +1 B are actually just as easy, just sort +of reversed. Uh so this was situation + + align:start position:0% +of reversed. Uh so this was situation + + + align:start position:0% +of reversed. Uh so this was situation +two. + + align:start position:0% +two. + + + align:start position:0% +two. +So either we got three mutual friends or + + align:start position:0% +So either we got three mutual friends or + + + align:start position:0% +So either we got three mutual friends or +we got three mutual strangers, but we're + + align:start position:0% +we got three mutual strangers, but we're + + + align:start position:0% +we got three mutual strangers, but we're +still inside case one. We just finished + + align:start position:0% +still inside case one. We just finished + + + align:start position:0% +still inside case one. We just finished +case one. Now we need to think about + + align:start position:0% +case one. Now we need to think about + + + align:start position:0% +case one. Now we need to think about +case two. So I'm going to unindent here + + align:start position:0% +case two. So I'm going to unindent here + + + align:start position:0% +case two. So I'm going to unindent here +and go to case two. + + align:start position:0% +and go to case two. + + + align:start position:0% +and go to case two. +Case two again has to be exactly the + + align:start position:0% +Case two again has to be exactly the + + + align:start position:0% +Case two again has to be exactly the +opposite of this. So P does not have at + + align:start position:0% +opposite of this. So P does not have at + + + align:start position:0% +opposite of this. So P does not have at +least three friends. + + align:start position:0% +least three friends. + + + align:start position:0% +least three friends. +Uh by + + align:start position:0% +Uh by + + + align:start position:0% +Uh by +number of people being an integer. This + + align:start position:0% +number of people being an integer. This + + + align:start position:0% +number of people being an integer. This +is saying P has at most two friends. + + align:start position:0% +is saying P has at most two friends. + + + align:start position:0% +is saying P has at most two friends. +Okay. If it doesn't have at least three, + + align:start position:0% +Okay. If it doesn't have at least three, + + + align:start position:0% +Okay. If it doesn't have at least three, +it's at most two because number of + + align:start position:0% +it's at most two because number of + + + align:start position:0% +it's at most two because number of +friends is always an integer. + + align:start position:0% +friends is always an integer. + + + align:start position:0% +friends is always an integer. +Okay, great. So that case two is a + + align:start position:0% +Okay, great. So that case two is a + + + align:start position:0% +Okay, great. So that case two is a +negation of case one. Um, and it turns + + align:start position:0% +negation of case one. Um, and it turns + + + align:start position:0% +negation of case one. Um, and it turns +out that is also kind of easy for a + + align:start position:0% +out that is also kind of easy for a + + + align:start position:0% +out that is also kind of easy for a +symmetric reason. Uh, remember there are + + align:start position:0% +symmetric reason. Uh, remember there are + + + align:start position:0% +symmetric reason. Uh, remember there are +six people total. So there's P and five + + align:start position:0% +six people total. So there's P and five + + + align:start position:0% +six people total. So there's P and five +others. + + align:start position:0% +others. + + + align:start position:0% +others. +So uh, how many strangers + + align:start position:0% + + + + align:start position:0% + +is P with or how many people is P a + + align:start position:0% +is P with or how many people is P a + + + align:start position:0% +is P with or how many people is P a +stranger to? + + align:start position:0% +stranger to? + + + align:start position:0% +stranger to? +Uh, well, it's at least uh, all the + + align:start position:0% +Uh, well, it's at least uh, all the + + + align:start position:0% +Uh, well, it's at least uh, all the +others. 5 minus 2 is at most two of them + + align:start position:0% +others. 5 minus 2 is at most two of them + + + align:start position:0% +others. 5 minus 2 is at most two of them +are friends. The remainder have to be + + align:start position:0% +are friends. The remainder have to be + + + align:start position:0% +are friends. The remainder have to be +strangers. And so this is three. + + align:start position:0% +strangers. And so this is three. + + + align:start position:0% +strangers. And so this is three. +So P having at most two friends is the + + align:start position:0% +So P having at most two friends is the + + + align:start position:0% +So P having at most two friends is the +same thing as P having at least three + + align:start position:0% +same thing as P having at least three + + + align:start position:0% +same thing as P having at least three +strangers because there are five other + + align:start position:0% +strangers because there are five other + + + align:start position:0% +strangers because there are five other +people total. 2 + 3 is 5. Uh so P case + + align:start position:0% +people total. 2 + 3 is 5. Uh so P case + + + align:start position:0% +people total. 2 + 3 is 5. Uh so P case +two is P has at least three strangers. + + align:start position:0% +two is P has at least three strangers. + + + align:start position:0% +two is P has at least three strangers. +Case one was P has at least three + + align:start position:0% +Case one was P has at least three + + + align:start position:0% +Case one was P has at least three +friends. These are almost the same. I + + align:start position:0% +friends. These are almost the same. I + + + align:start position:0% +friends. These are almost the same. I +just have to flip friends versus + + align:start position:0% +just have to flip friends versus + + + align:start position:0% +just have to flip friends versus +strangers. + + align:start position:0% +strangers. + + + align:start position:0% +strangers. +So the way I would write this in a proof + + align:start position:0% +So the way I would write this in a proof + + + align:start position:0% +So the way I would write this in a proof +is uh this is symmetric + + align:start position:0% + + + + align:start position:0% + +to case one + + align:start position:0% +to case one + + + align:start position:0% +to case one +uh + + align:start position:0% +uh + + + align:start position:0% +uh +swapping + + align:start position:0% + + + + align:start position:0% + +friends uh versus strangers. + + align:start position:0% + + + + align:start position:0% + +And of course uh case one or situation + + align:start position:0% +And of course uh case one or situation + + + align:start position:0% +And of course uh case one or situation +one with situation two. + + align:start position:0% +one with situation two. + + + align:start position:0% +one with situation two. +Okay. So case two would be P has at + + align:start position:0% +Okay. So case two would be P has at + + + align:start position:0% +Okay. So case two would be P has at +least three strangers QR and S. Case 1 A + + align:start position:0% +least three strangers QR and S. Case 1 A + + + align:start position:0% +least three strangers QR and S. Case 1 A +is that sum two of QR and S are + + align:start position:0% +is that sum two of QR and S are + + + align:start position:0% +is that sum two of QR and S are +strangers. Then we conclude that P plus + + align:start position:0% +strangers. Then we conclude that P plus + + + align:start position:0% +strangers. Then we conclude that P plus +those two are three mutual strangers + + align:start position:0% +those two are three mutual strangers + + + align:start position:0% +those two are three mutual strangers +which is situation two. Or case 2B would + + align:start position:0% +which is situation two. Or case 2B would + + + align:start position:0% +which is situation two. Or case 2B would +be no two of QRS are strangers. In other + + align:start position:0% +be no two of QRS are strangers. In other + + + align:start position:0% +be no two of QRS are strangers. In other +words, QRS are mutual friends. And then + + align:start position:0% +words, QRS are mutual friends. And then + + + align:start position:0% +words, QRS are mutual friends. And then +we're in situation one. So case two + + align:start position:0% +we're in situation one. So case two + + + align:start position:0% +we're in situation one. So case two +works just like case one just swapping + + align:start position:0% +works just like case one just swapping + + + align:start position:0% +works just like case one just swapping +the words friends and strangers because + + align:start position:0% +the words friends and strangers because + + + align:start position:0% +the words friends and strangers because +they didn't really have any meaning. + + align:start position:0% +they didn't really have any meaning. + + + align:start position:0% +they didn't really have any meaning. +They were just words. + + align:start position:0% +They were just words. + + + align:start position:0% +They were just words. +Cool. So in all cases + + align:start position:0% +Cool. So in all cases + + + align:start position:0% +Cool. So in all cases +uh we prove the desired result either + + align:start position:0% +uh we prove the desired result either + + + align:start position:0% +uh we prove the desired result either +situation one or situation two happens. + + align:start position:0% +situation one or situation two happens. + + + align:start position:0% +situation one or situation two happens. +Um this is a particular case of + + align:start position:0% +Um this is a particular case of + + + align:start position:0% +Um this is a particular case of +something called Ramsey theory. + + align:start position:0% + + + + align:start position:0% + +What we've just found is that something + + align:start position:0% +What we've just found is that something + + + align:start position:0% +What we've just found is that something +called r of 33 is uh at most six uh in + + align:start position:0% +called r of 33 is uh at most six uh in + + + align:start position:0% +called r of 33 is uh at most six uh in +general r of f comma s is the number of + + align:start position:0% +general r of f comma s is the number of + + + align:start position:0% +general r of f comma s is the number of +people you need uh in order to guarantee + + align:start position:0% +people you need uh in order to guarantee + + + align:start position:0% +people you need uh in order to guarantee +that there's at least f friends or at + + align:start position:0% +that there's at least f friends or at + + + align:start position:0% +that there's at least f friends or at +least s strangers. So we just did at + + align:start position:0% +least s strangers. So we just did at + + + align:start position:0% +least s strangers. So we just did at +least three friends or at least three + + align:start position:0% +least three friends or at least three + + + align:start position:0% +least three friends or at least three +strangers. We showed that six people was + + align:start position:0% +strangers. We showed that six people was + + + align:start position:0% +strangers. We showed that six people was +enough. It turns out uh six people is + + align:start position:0% +enough. It turns out uh six people is + + + align:start position:0% +enough. It turns out uh six people is +exactly the right number. You need six + + align:start position:0% +exactly the right number. You need six + + + align:start position:0% +exactly the right number. You need six +people in order to guarantee at least + + align:start position:0% +people in order to guarantee at least + + + align:start position:0% +people in order to guarantee at least +three friends or three strangers. If you + + align:start position:0% +three friends or three strangers. If you + + + align:start position:0% +three friends or three strangers. If you +wanted to guarantee four friends or four + + align:start position:0% +wanted to guarantee four friends or four + + + align:start position:0% +wanted to guarantee four friends or four +strangers, turns out you need 18 people. + + align:start position:0% +strangers, turns out you need 18 people. + + + align:start position:0% +strangers, turns out you need 18 people. +Uh if you want to guarantee five friends + + align:start position:0% +Uh if you want to guarantee five friends + + + align:start position:0% +Uh if you want to guarantee five friends +or five strangers, turns out you need uh + + align:start position:0% +or five strangers, turns out you need uh + + + align:start position:0% +or five strangers, turns out you need uh +somewhere between 43 and 48 people. But + + align:start position:0% +somewhere between 43 and 48 people. But + + + align:start position:0% +somewhere between 43 and 48 people. But +we don't know how many. So while this + + align:start position:0% +we don't know how many. So while this + + + align:start position:0% +we don't know how many. So while this +problem was relatively easy, three + + align:start position:0% +problem was relatively easy, three + + + align:start position:0% +problem was relatively easy, three +friends or three strangers, five friends + + align:start position:0% +friends or three strangers, five friends + + + align:start position:0% +friends or three strangers, five friends +and five strangers already is an + + align:start position:0% +and five strangers already is an + + + align:start position:0% +and five strangers already is an +unsolved mathematical problem. So that's + + align:start position:0% +unsolved mathematical problem. So that's + + + align:start position:0% +unsolved mathematical problem. So that's +kind of cool and crazy how easily you + + align:start position:0% +kind of cool and crazy how easily you + + + align:start position:0% +kind of cool and crazy how easily you +get to very difficult problems. Of + + align:start position:0% +get to very difficult problems. Of + + + align:start position:0% +get to very difficult problems. Of +course, people try to compute larger + + align:start position:0% +course, people try to compute larger + + + align:start position:0% +course, people try to compute larger +numbers too, but we don't have tight + + align:start position:0% +numbers too, but we don't have tight + + + align:start position:0% +numbers too, but we don't have tight +bounds generally. + + align:start position:0% +bounds generally. + + + align:start position:0% +bounds generally. +Okay, I want to say one more thing about + + align:start position:0% +Okay, I want to say one more thing about + + + align:start position:0% +Okay, I want to say one more thing about +proof by cases, which is what if we want + + align:start position:0% +proof by cases, which is what if we want + + + align:start position:0% +proof by cases, which is what if we want +more than two cases? + + align:start position:0% +more than two cases? + + + align:start position:0% +more than two cases? +Uh so + + align:start position:0% +Uh so + + + align:start position:0% +Uh so +more generally proof by K cases. + + align:start position:0% + + + + align:start position:0% + +So instead of just C or not C, let's + + align:start position:0% +So instead of just C or not C, let's + + + align:start position:0% +So instead of just C or not C, let's +suppose we have a bunch of propositions + + align:start position:0% +suppose we have a bunch of propositions + + + align:start position:0% +suppose we have a bunch of propositions +C1 through CK. And let's suppose that + + align:start position:0% +C1 through CK. And let's suppose that + + + align:start position:0% +C1 through CK. And let's suppose that +this is a tautology. + + align:start position:0% + + + + align:start position:0% + +favorite word for the day. So suppose + + align:start position:0% +favorite word for the day. So suppose + + + align:start position:0% +favorite word for the day. So suppose +that it's always the case C1 or C2 or + + align:start position:0% +that it's always the case C1 or C2 or + + + align:start position:0% +that it's always the case C1 or C2 or +dot dot dot or CK one of these things is + + align:start position:0% +dot dot dot or CK one of these things is + + + align:start position:0% +dot dot dot or CK one of these things is +always true. + + align:start position:0% +always true. + + + align:start position:0% +always true. +Then uh we can follow this template + + align:start position:0% + + + + align:start position:0% + +which is uh suppose we want to prove a + + align:start position:0% +which is uh suppose we want to prove a + + + align:start position:0% +which is uh suppose we want to prove a +theorem that some proposition P is true + + align:start position:0% +theorem that some proposition P is true + + + align:start position:0% +theorem that some proposition P is true +then we'll say proof + + align:start position:0% +then we'll say proof + + + align:start position:0% +then we'll say proof +uh by cases + + align:start position:0% +uh by cases + + + align:start position:0% +uh by cases +and + + align:start position:0% +and + + + align:start position:0% +and +there's K of them so I'm just going to + + align:start position:0% +there's K of them so I'm just going to + + + align:start position:0% +there's K of them so I'm just going to +write it generically in case I + + align:start position:0% +write it generically in case I + + + align:start position:0% +write it generically in case I +is that CI is true. In other words, we + + align:start position:0% +is that CI is true. In other words, we + + + align:start position:0% +is that CI is true. In other words, we +get to assume CI is true. + + align:start position:0% +get to assume CI is true. + + + align:start position:0% +get to assume CI is true. +And then what we need to do is prove + + align:start position:0% +And then what we need to do is prove + + + align:start position:0% +And then what we need to do is prove +that P is true in that scenario. And P + + align:start position:0% +that P is true in that scenario. And P + + + align:start position:0% +that P is true in that scenario. And P +is true + + align:start position:0% +is true + + + align:start position:0% +is true +because + + align:start position:0% +because + + + align:start position:0% +because +reasons. + + align:start position:0% + + + + align:start position:0% + +Uh and then here it's especially + + align:start position:0% +Uh and then here it's especially + + + align:start position:0% +Uh and then here it's especially +important to say that the cases + + align:start position:0% +important to say that the cases + + + align:start position:0% +important to say that the cases +are exhaustive. + + align:start position:0% + + + + align:start position:0% + +uh + + align:start position:0% +uh + + + align:start position:0% +uh +because + + align:start position:0% +because + + + align:start position:0% +because +reasons and exhaustive here just means + + align:start position:0% +reasons and exhaustive here just means + + + align:start position:0% +reasons and exhaustive here just means +that uh C1 or C2 or up to CK is a + + align:start position:0% +that uh C1 or C2 or up to CK is a + + + align:start position:0% +that uh C1 or C2 or up to CK is a +tautology. + + align:start position:0% + + + + align:start position:0% + +Okay, so you need to prove that C1 or or + + align:start position:0% +Okay, so you need to prove that C1 or or + + + align:start position:0% +Okay, so you need to prove that C1 or or +up dot dot dot or CK is is always true. + + align:start position:0% +up dot dot dot or CK is is always true. + + + align:start position:0% +up dot dot dot or CK is is always true. +That's the meaning of the cases being + + align:start position:0% +That's the meaning of the cases being + + + align:start position:0% +That's the meaning of the cases being +exhaustive. So there's sort of two + + align:start position:0% +exhaustive. So there's sort of two + + + align:start position:0% +exhaustive. So there's sort of two +parts. So one is to prove that each case + + align:start position:0% +parts. So one is to prove that each case + + + align:start position:0% +parts. So one is to prove that each case +is okay. The other is to prove that + + align:start position:0% +is okay. The other is to prove that + + + align:start position:0% +is okay. The other is to prove that +those cases cover everything. + + align:start position:0% +those cases cover everything. + + + align:start position:0% +those cases cover everything. +Okay. So um I won't show an example of K + + align:start position:0% +Okay. So um I won't show an example of K + + + align:start position:0% +Okay. So um I won't show an example of K +cases here. We'll see that I'm in + + align:start position:0% +cases here. We'll see that I'm in + + + align:start position:0% +cases here. We'll see that I'm in +restitation and so on. Uh but I will + + align:start position:0% +restitation and so on. Uh but I will + + + align:start position:0% +restitation and so on. Uh but I will +tell you a story about one uh famous + + align:start position:0% +tell you a story about one uh famous + + + align:start position:0% +tell you a story about one uh famous +proof by cases which is the fourcolor + + align:start position:0% +proof by cases which is the fourcolor + + + align:start position:0% +proof by cases which is the fourcolor +theorem. + + align:start position:0% +theorem. + + + align:start position:0% +theorem. +Uh I'll illustrate the four color + + align:start position:0% +Uh I'll illustrate the four color + + + align:start position:0% +Uh I'll illustrate the four color +theorem with an example. So here's a map + + align:start position:0% +theorem with an example. So here's a map + + + align:start position:0% +theorem with an example. So here's a map +of United States. uh and I've colored + + align:start position:0% +of United States. uh and I've colored + + + align:start position:0% +of United States. uh and I've colored +all the states, all the regions of this + + align:start position:0% +all the states, all the regions of this + + + align:start position:0% +all the states, all the regions of this +map with four different colors red, + + align:start position:0% +map with four different colors red, + + + align:start position:0% +map with four different colors red, +green, blue, yellow in such a way that + + align:start position:0% +green, blue, yellow in such a way that + + + align:start position:0% +green, blue, yellow in such a way that +if you have two regions that share a + + align:start position:0% +if you have two regions that share a + + + align:start position:0% +if you have two regions that share a +positive length boundary, then this + + align:start position:0% +positive length boundary, then this + + + align:start position:0% +positive length boundary, then this +color A is different from this color B. + + align:start position:0% +color A is different from this color B. + + + align:start position:0% +color A is different from this color B. +Okay, it has to be not equal. Otherwise, + + align:start position:0% +Okay, it has to be not equal. Otherwise, + + + align:start position:0% +Okay, it has to be not equal. Otherwise, +if you had two red regions next to each + + align:start position:0% +if you had two red regions next to each + + + align:start position:0% +if you had two red regions next to each +other, it' be hard to see the boundary. + + align:start position:0% +other, it' be hard to see the boundary. + + + align:start position:0% +other, it' be hard to see the boundary. +So the colors illustrate the boundaries + + align:start position:0% +So the colors illustrate the boundaries + + + align:start position:0% +So the colors illustrate the boundaries +between all the regions. Four colors + + align:start position:0% +between all the regions. Four colors + + + align:start position:0% +between all the regions. Four colors +seems to be enough for this map. Uh it's + + align:start position:0% +seems to be enough for this map. Uh it's + + + align:start position:0% +seems to be enough for this map. Uh it's +also enough for this map of all the + + align:start position:0% +also enough for this map of all the + + + align:start position:0% +also enough for this map of all the +countries. + + align:start position:0% +countries. + + + align:start position:0% +countries. +Is it true for all the maps? Turns out + + align:start position:0% +Is it true for all the maps? Turns out + + + align:start position:0% +Is it true for all the maps? Turns out +yes. This is called for a long time + + align:start position:0% +yes. This is called for a long time + + + align:start position:0% +yes. This is called for a long time +called the fourcolor conjecture and then + + align:start position:0% +called the fourcolor conjecture and then + + + align:start position:0% +called the fourcolor conjecture and then +it became the fourcolor theorem at some + + align:start position:0% +it became the fourcolor theorem at some + + + align:start position:0% +it became the fourcolor theorem at some +date. Uh so fourcolor theorem says you + + align:start position:0% +date. Uh so fourcolor theorem says you + + + align:start position:0% +date. Uh so fourcolor theorem says you +can color the regions of any planer map + + align:start position:0% +can color the regions of any planer map + + + align:start position:0% +can color the regions of any planer map +with four colors so the neighboring + + align:start position:0% +with four colors so the neighboring + + + align:start position:0% +with four colors so the neighboring +regions get different colors. This was + + align:start position:0% +regions get different colors. This was + + + align:start position:0% +regions get different colors. This was +first observed and sort of conjectured + + align:start position:0% +first observed and sort of conjectured + + + align:start position:0% +first observed and sort of conjectured +uh in 1852 by a guy named Guthrie who + + align:start position:0% +uh in 1852 by a guy named Guthrie who + + + align:start position:0% +uh in 1852 by a guy named Guthrie who +was a student of deorggan. De Morgan I + + align:start position:0% +was a student of deorggan. De Morgan I + + + align:start position:0% +was a student of deorggan. De Morgan I +think his name will come up in a moment + + align:start position:0% +think his name will come up in a moment + + + align:start position:0% +think his name will come up in a moment +famous logician. He actually invented + + align:start position:0% +famous logician. He actually invented + + + align:start position:0% +famous logician. He actually invented +induction as we + + align:start position:0% +induction as we + + + align:start position:0% +induction as we +one of the first people to he invented + + align:start position:0% +one of the first people to he invented + + + align:start position:0% +one of the first people to he invented +the term mathematical induction at the + + align:start position:0% +the term mathematical induction at the + + + align:start position:0% +the term mathematical induction at the +very least and really uh sort of made it + + align:start position:0% +very least and really uh sort of made it + + + align:start position:0% +very least and really uh sort of made it +more formal. + + align:start position:0% +more formal. + + + align:start position:0% +more formal. +Uh so a student of him Guthrie said hey + + align:start position:0% +Uh so a student of him Guthrie said hey + + + align:start position:0% +Uh so a student of him Guthrie said hey +I took all the counties of England and + + align:start position:0% +I took all the counties of England and + + + align:start position:0% +I took all the counties of England and +it turned out I only needed four colors + + align:start position:0% +it turned out I only needed four colors + + + align:start position:0% +it turned out I only needed four colors +is this a theorem and he asked uh + + align:start position:0% +is this a theorem and he asked uh + + + align:start position:0% +is this a theorem and he asked uh +indirectly de Morgan uh and Morgan said + + align:start position:0% +indirectly de Morgan uh and Morgan said + + + align:start position:0% +indirectly de Morgan uh and Morgan said +hey seems cool I don't know maybe then + + align:start position:0% +hey seems cool I don't know maybe then + + + align:start position:0% +hey seems cool I don't know maybe then +the following year 1853 + + align:start position:0% +the following year 1853 + + + align:start position:0% +the following year 1853 +uh another mathematician named Kemp + + align:start position:0% +uh another mathematician named Kemp + + + align:start position:0% +uh another mathematician named Kemp +uh + + align:start position:0% + + + + align:start position:0% + +proved the theorem + + align:start position:0% +proved the theorem + + + align:start position:0% +proved the theorem +but uh proved should be in quotes + + align:start position:0% +but uh proved should be in quotes + + + align:start position:0% +but uh proved should be in quotes +because uh 11 years later 1864 before + + align:start position:0% +because uh 11 years later 1864 before + + + align:start position:0% +because uh 11 years later 1864 before +Haywood found a bug in that proof. Turns + + align:start position:0% +Haywood found a bug in that proof. Turns + + + align:start position:0% +Haywood found a bug in that proof. Turns +out there were a lot of cases in this + + align:start position:0% +out there were a lot of cases in this + + + align:start position:0% +out there were a lot of cases in this +proof and the cases were not exhaustive. + + align:start position:0% +proof and the cases were not exhaustive. + + + align:start position:0% +proof and the cases were not exhaustive. +So it wasn't done. Then uh 15 years + + align:start position:0% +So it wasn't done. Then uh 15 years + + + align:start position:0% +So it wasn't done. Then uh 15 years +later, 1880, Tate proved the theorem. + + align:start position:0% +later, 1880, Tate proved the theorem. + + + align:start position:0% +later, 1880, Tate proved the theorem. +Then 11 years later, Peterson found a + + align:start position:0% +Then 11 years later, Peterson found a + + + align:start position:0% +Then 11 years later, Peterson found a +bug in that proof. Again, not all the + + align:start position:0% +bug in that proof. Again, not all the + + + align:start position:0% +bug in that proof. Again, not all the +cases were exhaustive. Then uh 85 years + + align:start position:0% +cases were exhaustive. Then uh 85 years + + + align:start position:0% +cases were exhaustive. Then uh 85 years +later, 1976 + + align:start position:0% +later, 1976 + + + align:start position:0% +later, 1976 +uh Apple and Haken or maybe it's a PEL, + + align:start position:0% +uh Apple and Haken or maybe it's a PEL, + + + align:start position:0% +uh Apple and Haken or maybe it's a PEL, +I'm not sure, uh + + align:start position:0% + + + + align:start position:0% + +proved the theorem and I think most + + align:start position:0% +proved the theorem and I think most + + + align:start position:0% +proved the theorem and I think most +people consider this an actual proof. Uh + + align:start position:0% +people consider this an actual proof. Uh + + + align:start position:0% +people consider this an actual proof. Uh +but it's a little tricky. Uh just to + + align:start position:0% +but it's a little tricky. Uh just to + + + align:start position:0% +but it's a little tricky. Uh just to +give you a sense, this this is where + + align:start position:0% +give you a sense, this this is where + + + align:start position:0% +give you a sense, this this is where +sort of my started I started hearing + + align:start position:0% +sort of my started I started hearing + + + align:start position:0% +sort of my started I started hearing +about the problem. I wasn't alive in + + align:start position:0% +about the problem. I wasn't alive in + + + align:start position:0% +about the problem. I wasn't alive in +1976, but I heard about it later on. Um + + align:start position:0% +1976, but I heard about it later on. Um + + + align:start position:0% +1976, but I heard about it later on. Um +there are 1,834 + + align:start position:0% +there are 1,834 + + + align:start position:0% +there are 1,834 +cases in this proof. They occupy about a + + align:start position:0% +cases in this proof. They occupy about a + + + align:start position:0% +cases in this proof. They occupy about a +400page printout from a computer + + align:start position:0% +400page printout from a computer + + + align:start position:0% +400page printout from a computer +program. And so th this is one of the + + align:start position:0% +program. And so th this is one of the + + + align:start position:0% +program. And so th this is one of the +first mathematical proofs that used a + + align:start position:0% +first mathematical proofs that used a + + + align:start position:0% +first mathematical proofs that used a +computer to assist in checking all the + + align:start position:0% +computer to assist in checking all the + + + align:start position:0% +computer to assist in checking all the +cases because there's so many 8 1,834. + + align:start position:0% +cases because there's so many 8 1,834. + + + align:start position:0% +cases because there's so many 8 1,834. +It's hard to do that by hand and be sure + + align:start position:0% +It's hard to do that by hand and be sure + + + align:start position:0% +It's hard to do that by hand and be sure +that you didn't make a mistake. So the + + align:start position:0% +that you didn't make a mistake. So the + + + align:start position:0% +that you didn't make a mistake. So the +computer proof to me is a little bit + + align:start position:0% +computer proof to me is a little bit + + + align:start position:0% +computer proof to me is a little bit +more sound. uh also apparently checked + + align:start position:0% +more sound. uh also apparently checked + + + align:start position:0% +more sound. uh also apparently checked +by hand uh by Haken's daughter. Um then + + align:start position:0% +by hand uh by Haken's daughter. Um then + + + align:start position:0% +by hand uh by Haken's daughter. Um then +five years later uh Schmidt found what + + align:start position:0% +five years later uh Schmidt found what + + + align:start position:0% +five years later uh Schmidt found what +you could interpret as a bug in this + + align:start position:0% +you could interpret as a bug in this + + + align:start position:0% +you could interpret as a bug in this +proof. Let's say an emission or + + align:start position:0% +proof. Let's say an emission or + + + align:start position:0% +proof. Let's say an emission or +something uh but a missing situation. Uh + + align:start position:0% +something uh but a missing situation. Uh + + + align:start position:0% +something uh but a missing situation. Uh +and then over the next eight years Apple + + align:start position:0% +and then over the next eight years Apple + + + align:start position:0% +and then over the next eight years Apple +and Haken fixed all the bugs they could + + align:start position:0% +and Haken fixed all the bugs they could + + + align:start position:0% +and Haken fixed all the bugs they could +find that one and some other sort of + + align:start position:0% +find that one and some other sort of + + + align:start position:0% +find that one and some other sort of +wording issues and so on and they + + align:start position:0% +wording issues and so on and they + + + align:start position:0% +wording issues and so on and they +proofed they published it in a book but + + align:start position:0% +proofed they published it in a book but + + + align:start position:0% +proofed they published it in a book but +book isn't refereed. So I don't know how + + align:start position:0% +book isn't refereed. So I don't know how + + + align:start position:0% +book isn't refereed. So I don't know how +many people have read that book. Um, + + align:start position:0% +many people have read that book. Um, + + + align:start position:0% +many people have read that book. Um, +seems like this proof is maybe correct. + + align:start position:0% +seems like this proof is maybe correct. + + + align:start position:0% +seems like this proof is maybe correct. +It's been many years and no one has + + align:start position:0% +It's been many years and no one has + + + align:start position:0% +It's been many years and no one has +found a bug. Uh, a little bit later + + align:start position:0% +found a bug. Uh, a little bit later + + + align:start position:0% +found a bug. Uh, a little bit later +though, 1996, Robertson, Sanders, + + align:start position:0% +though, 1996, Robertson, Sanders, + + + align:start position:0% +though, 1996, Robertson, Sanders, +Seymour, and Thomas, some of the top + + align:start position:0% +Seymour, and Thomas, some of the top + + + align:start position:0% +Seymour, and Thomas, some of the top +graph theorists in the world, uh, found + + align:start position:0% +graph theorists in the world, uh, found + + + align:start position:0% +graph theorists in the world, uh, found +a simpler proof. That proof only has 633 + + align:start position:0% +a simpler proof. That proof only has 633 + + + align:start position:0% +a simpler proof. That proof only has 633 +cases. So that's a lot less, maybe three + + align:start position:0% +cases. So that's a lot less, maybe three + + + align:start position:0% +cases. So that's a lot less, maybe three +times fewer cases. And also the length + + align:start position:0% +times fewer cases. And also the length + + + align:start position:0% +times fewer cases. And also the length +of the paper is shorter, maybe 10 times + + align:start position:0% +of the paper is shorter, maybe 10 times + + + align:start position:0% +of the paper is shorter, maybe 10 times +shorter. Uh so that's progress but you + + align:start position:0% +shorter. Uh so that's progress but you + + + align:start position:0% +shorter. Uh so that's progress but you +know is that proof true it also used a + + align:start position:0% +know is that proof true it also used a + + + align:start position:0% +know is that proof true it also used a +computer to check the cases. Uh finally + + align:start position:0% +computer to check the cases. Uh finally + + + align:start position:0% +computer to check the cases. Uh finally +in 2005 + + align:start position:0% +in 2005 + + + align:start position:0% +in 2005 +uh Verer and Gonier uh developed a fully + + align:start position:0% +uh Verer and Gonier uh developed a fully + + + align:start position:0% +uh Verer and Gonier uh developed a fully +computer checkable proof using uh a + + align:start position:0% +computer checkable proof using uh a + + + align:start position:0% +computer checkable proof using uh a +system called coaul where you write down + + align:start position:0% +system called coaul where you write down + + + align:start position:0% +system called coaul where you write down +uh every step in the proof and then the + + align:start position:0% +uh every step in the proof and then the + + + align:start position:0% +uh every step in the proof and then the +computer just has to check that every u + + align:start position:0% +computer just has to check that every u + + + align:start position:0% +computer just has to check that every u +mathematical derivation like all the + + align:start position:0% +mathematical derivation like all the + + + align:start position:0% +mathematical derivation like all the +derivations we saw last class modus + + align:start position:0% +derivations we saw last class modus + + + align:start position:0% +derivations we saw last class modus +ponus and all those things are correct. + + align:start position:0% +ponus and all those things are correct. + + + align:start position:0% +ponus and all those things are correct. +this this program has been has withstood + + align:start position:0% +this this program has been has withstood + + + align:start position:0% +this this program has been has withstood +many many years of scrutiny. So we all + + align:start position:0% +many many years of scrutiny. So we all + + + align:start position:0% +many many years of scrutiny. So we all +believe that it's correct and so the + + align:start position:0% +believe that it's correct and so the + + + align:start position:0% +believe that it's correct and so the +fact that you can write the entire proof + + align:start position:0% +fact that you can write the entire proof + + + align:start position:0% +fact that you can write the entire proof +in this proof language suggests that + + align:start position:0% +in this proof language suggests that + + + align:start position:0% +in this proof language suggests that +this really is a true theorem. Now + + align:start position:0% +this really is a true theorem. Now + + + align:start position:0% +this really is a true theorem. Now +thankfully there won't be more missing + + align:start position:0% +thankfully there won't be more missing + + + align:start position:0% +thankfully there won't be more missing +cases. I believe that is just an + + align:start position:0% +cases. I believe that is just an + + + align:start position:0% +cases. I believe that is just an +implementation of the Robertson proof. + + align:start position:0% +implementation of the Robertson proof. + + + align:start position:0% +implementation of the Robertson proof. +So uh that one withtood scrutiny but + + align:start position:0% +So uh that one withtood scrutiny but + + + align:start position:0% +So uh that one withtood scrutiny but +it's very tedious to write these proofs + + align:start position:0% +it's very tedious to write these proofs + + + align:start position:0% +it's very tedious to write these proofs +and so uh for the fourcolor theorem it's + + align:start position:0% +and so uh for the fourcolor theorem it's + + + align:start position:0% +and so uh for the fourcolor theorem it's +uh worth it I would say all right so + + align:start position:0% +uh worth it I would say all right so + + + align:start position:0% +uh worth it I would say all right so +that's just an example of in general + + align:start position:0% +that's just an example of in general + + + align:start position:0% +that's just an example of in general +proofs by cases can involve a zillion + + align:start position:0% +proofs by cases can involve a zillion + + + align:start position:0% +proofs by cases can involve a zillion +cases it's very annoying but sometimes + + align:start position:0% +cases it's very annoying but sometimes + + + align:start position:0% +cases it's very annoying but sometimes +that's the best thing we know how to do + + align:start position:0% +that's the best thing we know how to do + + + align:start position:0% +that's the best thing we know how to do +maybe we'll come up with a simpler + + align:start position:0% +maybe we'll come up with a simpler + + + align:start position:0% +maybe we'll come up with a simpler +fourcolor theorem proof at some point + + align:start position:0% +fourcolor theorem proof at some point + + + align:start position:0% +fourcolor theorem proof at some point +but best we know so far has hundreds of + + align:start position:0% +but best we know so far has hundreds of + + + align:start position:0% +but best we know so far has hundreds of +cases + + align:start position:0% +cases + + + align:start position:0% +cases +all right let's go back to induction + + align:start position:0% +all right let's go back to induction + + + align:start position:0% +all right let's go back to induction +Uh first I want to review induction a + + align:start position:0% +Uh first I want to review induction a + + + align:start position:0% +Uh first I want to review induction a +little bit and then we will get a + + align:start position:0% +little bit and then we will get a + + + align:start position:0% +little bit and then we will get a +stronger form of it. + + align:start position:0% + + + + align:start position:0% + +So uh I'm going to call this the + + align:start position:0% +So uh I'm going to call this the + + + align:start position:0% +So uh I'm going to call this the +induction axiom. This is what we talked + + align:start position:0% +induction axiom. This is what we talked + + + align:start position:0% +induction axiom. This is what we talked +about last class. Uh we didn't call it + + align:start position:0% +about last class. Uh we didn't call it + + + align:start position:0% +about last class. Uh we didn't call it +an axiom and in some setups it is an + + align:start position:0% +an axiom and in some setups it is an + + + align:start position:0% +an axiom and in some setups it is an +axiom. We're going to take it as one. + + align:start position:0% +axiom. We're going to take it as one. + + + align:start position:0% +axiom. We're going to take it as one. +something that we just assume is true. + + align:start position:0% +something that we just assume is true. + + + align:start position:0% +something that we just assume is true. +Uh although as Zach mentioned in modern + + align:start position:0% +Uh although as Zach mentioned in modern + + + align:start position:0% +Uh although as Zach mentioned in modern +times you usually prove this using other + + align:start position:0% +times you usually prove this using other + + + align:start position:0% +times you usually prove this using other +using the definition of the natural + + align:start position:0% +using the definition of the natural + + + align:start position:0% +using the definition of the natural +numbers. + + align:start position:0% +numbers. + + + align:start position:0% +numbers. +Uh but I'll just take it as something is + + align:start position:0% +Uh but I'll just take it as something is + + + align:start position:0% +Uh but I'll just take it as something is +true. So for any predicate p of n over + + align:start position:0% +true. So for any predicate p of n over + + + align:start position:0% +true. So for any predicate p of n over +the natural numbers if on the one hand p + + align:start position:0% +the natural numbers if on the one hand p + + + align:start position:0% +the natural numbers if on the one hand p +of zero is true + + align:start position:0% +of zero is true + + + align:start position:0% +of zero is true +and on the other hand + + align:start position:0% +and on the other hand + + + align:start position:0% +and on the other hand +uh + + align:start position:0% +uh + + + align:start position:0% +uh +p of n implies p of n + one + + align:start position:0% +p of n implies p of n + one + + + align:start position:0% +p of n implies p of n + one +uh for all natural numbers n + + align:start position:0% +uh for all natural numbers n + + + align:start position:0% +uh for all natural numbers n +then + + align:start position:0% +then + + + align:start position:0% +then +uh p of n is true uh for all natural + + align:start position:0% +uh p of n is true uh for all natural + + + align:start position:0% +uh p of n is true uh for all natural +numbers + + align:start position:0% +numbers + + + align:start position:0% +numbers +Okay, this is the magic of induction. + + align:start position:0% +Okay, this is the magic of induction. + + + align:start position:0% +Okay, this is the magic of induction. +You should use this probably in every + + align:start position:0% +You should use this probably in every + + + align:start position:0% +You should use this probably in every +problem you solve. Not every problem, + + align:start position:0% +problem you solve. Not every problem, + + + align:start position:0% +problem you solve. Not every problem, +but uh extremely powerful tool. We're + + align:start position:0% +but uh extremely powerful tool. We're + + + align:start position:0% +but uh extremely powerful tool. We're +going to use it all the time throughout + + align:start position:0% +going to use it all the time throughout + + + align:start position:0% +going to use it all the time throughout +this class. I want to give you a visual + + align:start position:0% +this class. I want to give you a visual + + + align:start position:0% +this class. I want to give you a visual +way of thinking about what's going on + + align:start position:0% +way of thinking about what's going on + + + align:start position:0% +way of thinking about what's going on +with induction, which I call block + + align:start position:0% +with induction, which I call block + + + align:start position:0% +with induction, which I call block +diagrams. + + align:start position:0% + + + + align:start position:0% + +Uh so um I'm going to think of + + align:start position:0% +Uh so um I'm going to think of + + + align:start position:0% +Uh so um I'm going to think of +a block + + align:start position:0% + + + + align:start position:0% + +like a little box here that takes as + + align:start position:0% +like a little box here that takes as + + + align:start position:0% +like a little box here that takes as +input. Think of it as a procedure. You + + align:start position:0% +input. Think of it as a procedure. You + + + align:start position:0% +input. Think of it as a procedure. You +give it some true uh propositions on the + + align:start position:0% +give it some true uh propositions on the + + + align:start position:0% +give it some true uh propositions on the +left and it produces a true proposition + + align:start position:0% +left and it produces a true proposition + + + align:start position:0% +left and it produces a true proposition +on the right. + + align:start position:0% + + + + align:start position:0% + +Okay? Or you could think of it as if I + + align:start position:0% +Okay? Or you could think of it as if I + + + align:start position:0% +Okay? Or you could think of it as if I +give you some proofs of these + + align:start position:0% +give you some proofs of these + + + align:start position:0% +give you some proofs of these +propositions, then this block will give + + align:start position:0% +propositions, then this block will give + + + align:start position:0% +propositions, then this block will give +you uh a proof of a proposition on the + + align:start position:0% +you uh a proof of a proposition on the + + + align:start position:0% +you uh a proof of a proposition on the +right. Okay? So, uh what's going on with + + align:start position:0% +right. Okay? So, uh what's going on with + + + align:start position:0% +right. Okay? So, uh what's going on with +induction is we're given two of these + + align:start position:0% +induction is we're given two of these + + + align:start position:0% +induction is we're given two of these +blocks, these two. So, you can think of + + align:start position:0% +blocks, these two. So, you can think of + + + align:start position:0% +blocks, these two. So, you can think of +part one P of 0 is true as a block that + + align:start position:0% +part one P of 0 is true as a block that + + + align:start position:0% +part one P of 0 is true as a block that +has no input. So, this is what we + + align:start position:0% +has no input. So, this is what we + + + align:start position:0% +has no input. So, this is what we +normally call the base case. So it + + align:start position:0% +normally call the base case. So it + + + align:start position:0% +normally call the base case. So it +doesn't need to assume anything and it + + align:start position:0% +doesn't need to assume anything and it + + + align:start position:0% +doesn't need to assume anything and it +just produces for you a proof that P of + + align:start position:0% +just produces for you a proof that P of + + + align:start position:0% +just produces for you a proof that P of +0 is true. + + align:start position:0% +0 is true. + + + align:start position:0% +0 is true. +Okay. And the second part here, the + + align:start position:0% +Okay. And the second part here, the + + + align:start position:0% +Okay. And the second part here, the +induction step + + align:start position:0% +induction step + + + align:start position:0% +induction step +says that if you can prove P of N is + + align:start position:0% +says that if you can prove P of N is + + + align:start position:0% +says that if you can prove P of N is +true and you plug it into the induction + + align:start position:0% +true and you plug it into the induction + + + align:start position:0% +true and you plug it into the induction +step, then it will give you a proof that + + align:start position:0% +step, then it will give you a proof that + + + align:start position:0% +step, then it will give you a proof that +P of N plus one is true. Saw a bunch of + + align:start position:0% +P of N plus one is true. Saw a bunch of + + + align:start position:0% +P of N plus one is true. Saw a bunch of +examples of this last time. We assume P + + align:start position:0% +examples of this last time. We assume P + + + align:start position:0% +examples of this last time. We assume P +of N and we use that to prove P of N + + align:start position:0% +of N and we use that to prove P of N + + + align:start position:0% +of N and we use that to prove P of N +plus one. Okay. Now the cool thing about + + align:start position:0% +plus one. Okay. Now the cool thing about + + + align:start position:0% +plus one. Okay. Now the cool thing about +blocks is you can just uh chain them + + align:start position:0% +blocks is you can just uh chain them + + + align:start position:0% +blocks is you can just uh chain them +together. + + align:start position:0% +together. + + + align:start position:0% +together. +So if we chain + + align:start position:0% +So if we chain + + + align:start position:0% +So if we chain +uh the only block we can place first is + + align:start position:0% +uh the only block we can place first is + + + align:start position:0% +uh the only block we can place first is +uh this base case because it doesn't + + align:start position:0% +uh this base case because it doesn't + + + align:start position:0% +uh this base case because it doesn't +need anything to get started. So we + + align:start position:0% +need anything to get started. So we + + + align:start position:0% +need anything to get started. So we +start with the base case argument that + + align:start position:0% +start with the base case argument that + + + align:start position:0% +start with the base case argument that +produces P of zero. Now we plug this + + align:start position:0% +produces P of zero. Now we plug this + + + align:start position:0% +produces P of zero. Now we plug this +into the step. This step has to work for + + align:start position:0% +into the step. This step has to work for + + + align:start position:0% +into the step. This step has to work for +all n. + + align:start position:0% +all n. + + + align:start position:0% +all n. +So in particular it works for n equals + + align:start position:0% +So in particular it works for n equals + + + align:start position:0% +So in particular it works for n equals +z. And so we plug that into the step and + + align:start position:0% +z. And so we plug that into the step and + + + align:start position:0% +z. And so we plug that into the step and +we get uh p of 1. We plug p of 1 into + + align:start position:0% +we get uh p of 1. We plug p of 1 into + + + align:start position:0% +we get uh p of 1. We plug p of 1 into +the step. So n equals 1. + + align:start position:0% +the step. So n equals 1. + + + align:start position:0% +the step. So n equals 1. +Then we get p of n plus one namely p of + + align:start position:0% +Then we get p of n plus one namely p of + + + align:start position:0% +Then we get p of n plus one namely p of +two. And we plug that into the step and + + align:start position:0% +two. And we plug that into the step and + + + align:start position:0% +two. And we plug that into the step and +we get p of three and so on. + + align:start position:0% +we get p of three and so on. + + + align:start position:0% +we get p of three and so on. +Okay. Okay, so this just gives you some + + align:start position:0% +Okay. Okay, so this just gives you some + + + align:start position:0% +Okay. Okay, so this just gives you some +intuition for if I can build an argument + + align:start position:0% +intuition for if I can build an argument + + + align:start position:0% +intuition for if I can build an argument +for why P of 0 is true and I can build + + align:start position:0% +for why P of 0 is true and I can build + + + align:start position:0% +for why P of 0 is true and I can build +an argument for why if P of N is true + + align:start position:0% +an argument for why if P of N is true + + + align:start position:0% +an argument for why if P of N is true +then P of N plus one is also true then I + + align:start position:0% +then P of N plus one is also true then I + + + align:start position:0% +then P of N plus one is also true then I +can just repeat that argument over and + + align:start position:0% +can just repeat that argument over and + + + align:start position:0% +can just repeat that argument over and +over with different n increasing N by + + align:start position:0% +over with different n increasing N by + + + align:start position:0% +over with different n increasing N by +one each time and I can use that to + + align:start position:0% +one each time and I can use that to + + + align:start position:0% +one each time and I can use that to +prove that all the P of N's are true. + + align:start position:0% +prove that all the P of N's are true. + + + align:start position:0% +prove that all the P of N's are true. +Okay, this is like visual intuition for + + align:start position:0% +Okay, this is like visual intuition for + + + align:start position:0% +Okay, this is like visual intuition for +why why this works. Um, of course, we're + + align:start position:0% +why why this works. Um, of course, we're + + + align:start position:0% +why why this works. Um, of course, we're +not going to actually prove P of N is + + align:start position:0% +not going to actually prove P of N is + + + align:start position:0% +not going to actually prove P of N is +true for all N, but uh should be pretty + + align:start position:0% +true for all N, but uh should be pretty + + + align:start position:0% +true for all N, but uh should be pretty +straight pretty intuitive from that. + + align:start position:0% +straight pretty intuitive from that. + + + align:start position:0% +straight pretty intuitive from that. +Uh or more abstractly + + align:start position:0% + + + + align:start position:0% + +you can actually think of induction + + align:start position:0% +you can actually think of induction + + + align:start position:0% +you can actually think of induction +itself as one of these blocks. Uh let me + + align:start position:0% +itself as one of these blocks. Uh let me + + + align:start position:0% +itself as one of these blocks. Uh let me +use another color. + + align:start position:0% + + + + align:start position:0% + +So we have on the one hand uh a block + + align:start position:0% +So we have on the one hand uh a block + + + align:start position:0% +So we have on the one hand uh a block +base which produces P of zero and we + + align:start position:0% +base which produces P of zero and we + + + align:start position:0% +base which produces P of zero and we +have uh an induction step which given P + + align:start position:0% +have uh an induction step which given P + + + align:start position:0% +have uh an induction step which given P +of N produces + + align:start position:0% +of N produces + + + align:start position:0% +of N produces +uh P of N plus one. + + align:start position:0% +uh P of N plus one. + + + align:start position:0% +uh P of N plus one. +So I'm going to think of this as a thing + + align:start position:0% +So I'm going to think of this as a thing + + + align:start position:0% +So I'm going to think of this as a thing +that's true and this as a thing that's + + align:start position:0% +that's true and this as a thing that's + + + align:start position:0% +that's true and this as a thing that's +true. And then what induction gives me? + + align:start position:0% +true. And then what induction gives me? + + + align:start position:0% +true. And then what induction gives me? +Induction is a block that given these + + align:start position:0% +Induction is a block that given these + + + align:start position:0% +Induction is a block that given these +two facts, if you can prove each of + + align:start position:0% +two facts, if you can prove each of + + + align:start position:0% +two facts, if you can prove each of +these things, then it gives me a new + + align:start position:0% +these things, then it gives me a new + + + align:start position:0% +these things, then it gives me a new +fact which is uh for all natural numbers + + align:start position:0% +fact which is uh for all natural numbers + + + align:start position:0% +fact which is uh for all natural numbers +n uh p of n is true. + + align:start position:0% +n uh p of n is true. + + + align:start position:0% +n uh p of n is true. +Okay, so that's sort of the instead of + + align:start position:0% +Okay, so that's sort of the instead of + + + align:start position:0% +Okay, so that's sort of the instead of +having to draw out this infinite length + + align:start position:0% +having to draw out this infinite length + + + align:start position:0% +having to draw out this infinite length +path, induction just does it all at + + align:start position:0% +path, induction just does it all at + + + align:start position:0% +path, induction just does it all at +once. It says, "Oh, I know I can chain + + align:start position:0% +once. It says, "Oh, I know I can chain + + + align:start position:0% +once. It says, "Oh, I know I can chain +these all together forever. Therefore, P + + align:start position:0% +these all together forever. Therefore, P + + + align:start position:0% +these all together forever. Therefore, P +of N is true for all N." Okay, I don't + + align:start position:0% +of N is true for all N." Okay, I don't + + + align:start position:0% +of N is true for all N." Okay, I don't +know if that helps, but + + align:start position:0% +know if that helps, but + + + align:start position:0% +know if that helps, but +it's another visual way of thinking + + align:start position:0% +it's another visual way of thinking + + + align:start position:0% +it's another visual way of thinking +about induction. + + align:start position:0% + + + + align:start position:0% + +Let's um + + align:start position:0% + + + + align:start position:0% + +All right. + + align:start position:0% +All right. + + + align:start position:0% +All right. +Let me tell you another uh equivalent + + align:start position:0% +Let me tell you another uh equivalent + + + align:start position:0% +Let me tell you another uh equivalent +formulation of induction which I prefer. + + align:start position:0% + + + + align:start position:0% + +starts out starts out the same. Suppose + + align:start position:0% +starts out starts out the same. Suppose + + + align:start position:0% +starts out starts out the same. Suppose +P of 0 is true. Uh the second the + + align:start position:0% +P of 0 is true. Uh the second the + + + align:start position:0% +P of 0 is true. Uh the second the +induction step I'm going to phrase + + align:start position:0% +induction step I'm going to phrase + + + align:start position:0% +induction step I'm going to phrase +slightly differently almost the same. + + align:start position:0% +slightly differently almost the same. + + + align:start position:0% +slightly differently almost the same. +For all n at least one + + align:start position:0% +For all n at least one + + + align:start position:0% +For all n at least one +uh p of n minus one implies p of n. + + align:start position:0% + + + + align:start position:0% + +Then + + align:start position:0% +Then + + + align:start position:0% +Then +uh for all natural numbers + + align:start position:0% +uh for all natural numbers + + + align:start position:0% +uh for all natural numbers +uh p of n. + + align:start position:0% +uh p of n. + + + align:start position:0% +uh p of n. +So uh the first and last lines are the + + align:start position:0% +So uh the first and last lines are the + + + align:start position:0% +So uh the first and last lines are the +same. We're assume P of 0 is true. We're + + align:start position:0% +same. We're assume P of 0 is true. We're + + + align:start position:0% +same. We're assume P of 0 is true. We're +going to conclude P of N is true for all + + align:start position:0% +going to conclude P of N is true for all + + + align:start position:0% +going to conclude P of N is true for all +natural numbers. Here we started at zero + + align:start position:0% +natural numbers. Here we started at zero + + + align:start position:0% +natural numbers. Here we started at zero +and we wanted to show that P of N + + align:start position:0% +and we wanted to show that P of N + + + align:start position:0% +and we wanted to show that P of N +implies P of N plus one. Over here we're + + align:start position:0% +implies P of N plus one. Over here we're + + + align:start position:0% +implies P of N plus one. Over here we're +starting at one and we're proving that P + + align:start position:0% +starting at one and we're proving that P + + + align:start position:0% +starting at one and we're proving that P +of N minus one implies P of N. These are + + align:start position:0% +of N minus one implies P of N. These are + + + align:start position:0% +of N minus one implies P of N. These are +exactly the same things. I've just + + align:start position:0% +exactly the same things. I've just + + + align:start position:0% +exactly the same things. I've just +shifted the indices by one. So these are + + align:start position:0% +shifted the indices by one. So these are + + + align:start position:0% +shifted the indices by one. So these are +identical statements or equivalent + + align:start position:0% +identical statements or equivalent + + + align:start position:0% +identical statements or equivalent +statements. Um I like this version in + + align:start position:0% +statements. Um I like this version in + + + align:start position:0% +statements. Um I like this version in +particular. it will lead into strong + + align:start position:0% +particular. it will lead into strong + + + align:start position:0% +particular. it will lead into strong +induction. But I like this version as a + + align:start position:0% +induction. But I like this version as a + + + align:start position:0% +induction. But I like this version as a +computer scientist because I always want + + align:start position:0% +computer scientist because I always want + + + align:start position:0% +computer scientist because I always want +to think about well I want to prove P of + + align:start position:0% +to think about well I want to prove P of + + + align:start position:0% +to think about well I want to prove P of +N not P of N plus one. It's confusing to + + align:start position:0% +N not P of N plus one. It's confusing to + + + align:start position:0% +N not P of N plus one. It's confusing to +think about proving P of N plus one. I + + align:start position:0% +think about proving P of N plus one. I + + + align:start position:0% +think about proving P of N plus one. I +always want to prove P of N when N + + align:start position:0% +always want to prove P of N when N + + + align:start position:0% +always want to prove P of N when N +equals zero. Okay, that's my base case. + + align:start position:0% +equals zero. Okay, that's my base case. + + + align:start position:0% +equals zero. Okay, that's my base case. +I prove that specially when N is at + + align:start position:0% +I prove that specially when N is at + + + align:start position:0% +I prove that specially when N is at +least one. I'm not in the base case and + + align:start position:0% +least one. I'm not in the base case and + + + align:start position:0% +least one. I'm not in the base case and +I get to assume that P of N minus one is + + align:start position:0% +I get to assume that P of N minus one is + + + align:start position:0% +I get to assume that P of N minus one is +true. You can think of this like a + + align:start position:0% +true. You can think of this like a + + + align:start position:0% +true. You can think of this like a +computer program. Think of a proving p + + align:start position:0% +computer program. Think of a proving p + + + align:start position:0% +computer program. Think of a proving p +of n is like running a computation f of + + align:start position:0% +of n is like running a computation f of + + + align:start position:0% +of n is like running a computation f of +n or p of n and I get to recursively + + align:start position:0% +n or p of n and I get to recursively + + + align:start position:0% +n or p of n and I get to recursively +call p of n minus one in order to + + align:start position:0% +call p of n minus one in order to + + + align:start position:0% +call p of n minus one in order to +compute p of n. n is given to me. This + + align:start position:0% +compute p of n. n is given to me. This + + + align:start position:0% +compute p of n. n is given to me. This +is the one I want to solve. If n is zero + + align:start position:0% +is the one I want to solve. If n is zero + + + align:start position:0% +is the one I want to solve. If n is zero +then I solve it one way. If n is bigger + + align:start position:0% +then I solve it one way. If n is bigger + + + align:start position:0% +then I solve it one way. If n is bigger +than zero or at least one then I + + align:start position:0% +than zero or at least one then I + + + align:start position:0% +than zero or at least one then I +recursively call p of n minus one or + + align:start position:0% +recursively call p of n minus one or + + + align:start position:0% +recursively call p of n minus one or +depend on that proof and use it to prove + + align:start position:0% +depend on that proof and use it to prove + + + align:start position:0% +depend on that proof and use it to prove +p of n. Okay. But you can use either one + + align:start position:0% +p of n. Okay. But you can use either one + + + align:start position:0% +p of n. Okay. But you can use either one +whichever is more comfortable to you. + + align:start position:0% +whichever is more comfortable to you. + + + align:start position:0% +whichever is more comfortable to you. +uh but really you should use neither and + + align:start position:0% +uh but really you should use neither and + + + align:start position:0% +uh but really you should use neither and +you should use this stronger form uh + + align:start position:0% +you should use this stronger form uh + + + align:start position:0% +you should use this stronger form uh +called strong induction. So let's let's + + align:start position:0% +called strong induction. So let's let's + + + align:start position:0% +called strong induction. So let's let's +do that. + + align:start position:0% + + + + align:start position:0% + +Strong induction just gives you more to + + align:start position:0% +Strong induction just gives you more to + + + align:start position:0% +Strong induction just gives you more to +work with. + + align:start position:0% + + + + align:start position:0% + +So it's in some sense more powerful + + align:start position:0% +So it's in some sense more powerful + + + align:start position:0% +So it's in some sense more powerful +logically it's identical to induction. + + align:start position:0% +logically it's identical to induction. + + + align:start position:0% +logically it's identical to induction. +You can actually prove it using + + align:start position:0% +You can actually prove it using + + + align:start position:0% +You can actually prove it using +induction and we'll do that. Uh let me + + align:start position:0% +induction and we'll do that. Uh let me + + + align:start position:0% +induction and we'll do that. Uh let me +first state the theorem. So if + + align:start position:0% +first state the theorem. So if + + + align:start position:0% +first state the theorem. So if +any natural number + + align:start position:0% + + + + align:start position:0% + +this is true + + align:start position:0% +this is true + + + align:start position:0% +this is true +then + + align:start position:0% +then + + + align:start position:0% +then +uh any natural number p of n is true. + + align:start position:0% +uh any natural number p of n is true. + + + align:start position:0% +uh any natural number p of n is true. +Okay. Uh let me bring this one down to + + align:start position:0% +Okay. Uh let me bring this one down to + + + align:start position:0% +Okay. Uh let me bring this one down to +compare. + + align:start position:0% +compare. + + + align:start position:0% +compare. +Uh + + align:start position:0% + + + + align:start position:0% + +so uh first thing maybe to notice is + + align:start position:0% +so uh first thing maybe to notice is + + + align:start position:0% +so uh first thing maybe to notice is +there doesn't seem to be a base case + + align:start position:0% +there doesn't seem to be a base case + + + align:start position:0% +there doesn't seem to be a base case +here. uh which is a little weird. It's + + align:start position:0% +here. uh which is a little weird. It's + + + align:start position:0% +here. uh which is a little weird. It's +just one condition then this let's + + align:start position:0% +just one condition then this let's + + + align:start position:0% +just one condition then this let's +compare the steps first of all um so or + + align:start position:0% +compare the steps first of all um so or + + + align:start position:0% +compare the steps first of all um so or +I guess let's let's think about the case + + align:start position:0% +I guess let's let's think about the case + + + align:start position:0% +I guess let's let's think about the case +this has to be true for all n if we + + align:start position:0% +this has to be true for all n if we + + + align:start position:0% +this has to be true for all n if we +think about when n equals 0 that's the + + align:start position:0% +think about when n equals 0 that's the + + + align:start position:0% +think about when n equals 0 that's the +missing base case what this is actually + + align:start position:0% +missing base case what this is actually + + + align:start position:0% +missing base case what this is actually +saying is p 0 up to p minus one implies + + align:start position:0% +saying is p 0 up to p minus one implies + + + align:start position:0% +saying is p 0 up to p minus one implies +p of zero okay so this is kind of weird + + align:start position:0% +p of zero okay so this is kind of weird + + + align:start position:0% +p of zero okay so this is kind of weird +notation I'm I'm abusing the dot dot dot + + align:start position:0% +notation I'm I'm abusing the dot dot dot + + + align:start position:0% +notation I'm I'm abusing the dot dot dot +a little bit here and uh for when n + + align:start position:0% +a little bit here and uh for when n + + + align:start position:0% +a little bit here and uh for when n +equals one this is p of 0 when n equals + + align:start position:0% +equals one this is p of 0 when n equals + + + align:start position:0% +equals one this is p of 0 when n equals +2 this is p of 0 and p of 1 when n + + align:start position:0% +2 this is p of 0 and p of 1 when n + + + align:start position:0% +2 this is p of 0 and p of 1 when n +equals 3 I mean for a larger n it's very + + align:start position:0% +equals 3 I mean for a larger n it's very + + + align:start position:0% +equals 3 I mean for a larger n it's very +clear what this dot dot dot means but + + align:start position:0% +clear what this dot dot dot means but + + + align:start position:0% +clear what this dot dot dot means but +when n equals 0 it's confusing so I need + + align:start position:0% +when n equals 0 it's confusing so I need + + + align:start position:0% +when n equals 0 it's confusing so I need +to specify uh this is defined to be true + + align:start position:0% +to specify uh this is defined to be true + + + align:start position:0% +to specify uh this is defined to be true +uh for n equals 0 + + align:start position:0% +uh for n equals 0 + + + align:start position:0% +uh for n equals 0 +okay so for n equals 0 what you have to + + align:start position:0% +okay so for n equals 0 what you have to + + + align:start position:0% +okay so for n equals 0 what you have to +do is prove that true implies p of zero + + align:start position:0% +do is prove that true implies p of zero + + + align:start position:0% +do is prove that true implies p of zero +in other words p of zero must be true in + + align:start position:0% +in other words p of zero must be true in + + + align:start position:0% +in other words p of zero must be true in +all cases okay so there's Um, but then + + align:start position:0% +all cases okay so there's Um, but then + + + align:start position:0% +all cases okay so there's Um, but then +for larger n, what this is saying is not + + align:start position:0% +for larger n, what this is saying is not + + + align:start position:0% +for larger n, what this is saying is not +only do I get to assume p of n minus + + align:start position:0% +only do I get to assume p of n minus + + + align:start position:0% +only do I get to assume p of n minus +one, but I get to assume all the p of + + align:start position:0% +one, but I get to assume all the p of + + + align:start position:0% +one, but I get to assume all the p of +i's before p of n. So I would I would + + align:start position:0% +i's before p of n. So I would I would + + + align:start position:0% +i's before p of n. So I would I would +normally say uh p of i is true for all i + + align:start position:0% +normally say uh p of i is true for all i + + + align:start position:0% +normally say uh p of i is true for all i +less than n. This is what I get to + + align:start position:0% +less than n. This is what I get to + + + align:start position:0% +less than n. This is what I get to +assume. + + align:start position:0% +assume. + + + align:start position:0% +assume. +That's probably actually a better way to + + align:start position:0% +That's probably actually a better way to + + + align:start position:0% +That's probably actually a better way to +state this this thing. + + align:start position:0% +state this this thing. + + + align:start position:0% +state this this thing. +So with regular induction here, I got to + + align:start position:0% +So with regular induction here, I got to + + + align:start position:0% +So with regular induction here, I got to +assume that the previous P of N minus + + align:start position:0% +assume that the previous P of N minus + + + align:start position:0% +assume that the previous P of N minus +one was true and I needed to use that to + + align:start position:0% +one was true and I needed to use that to + + + align:start position:0% +one was true and I needed to use that to +pro prove that P of N is true. But + + align:start position:0% +pro prove that P of N is true. But + + + align:start position:0% +pro prove that P of N is true. But +actually if you look at this chain like + + align:start position:0% +actually if you look at this chain like + + + align:start position:0% +actually if you look at this chain like +by the time I'm proving P of three, I've + + align:start position:0% +by the time I'm proving P of three, I've + + + align:start position:0% +by the time I'm proving P of three, I've +already proved all the smaller PIs. + + align:start position:0% +already proved all the smaller PIs. + + + align:start position:0% +already proved all the smaller PIs. +So why not and assume that with strong + + align:start position:0% +So why not and assume that with strong + + + align:start position:0% +So why not and assume that with strong +induction I get to assume that in order + + align:start position:0% +induction I get to assume that in order + + + align:start position:0% +induction I get to assume that in order +to prove P of N I get to assume all the + + align:start position:0% +to prove P of N I get to assume all the + + + align:start position:0% +to prove P of N I get to assume all the +PI's where I is less than M. Okay. Now + + align:start position:0% +PI's where I is less than M. Okay. Now + + + align:start position:0% +PI's where I is less than M. Okay. Now +when N equals Z, I don't get to assume + + align:start position:0% +when N equals Z, I don't get to assume + + + align:start position:0% +when N equals Z, I don't get to assume +anything because there are no smaller + + align:start position:0% +anything because there are no smaller + + + align:start position:0% +anything because there are no smaller +I's. Uh but when I get to P of five, I + + align:start position:0% +I's. Uh but when I get to P of five, I + + + align:start position:0% +I's. Uh but when I get to P of five, I +get to assume P 0, P4, P 0, P1, P2, P3, + + align:start position:0% +get to assume P 0, P4, P 0, P1, P2, P3, + + + align:start position:0% +get to assume P 0, P4, P 0, P1, P2, P3, +P4. Uh so I get to assume more. So this + + align:start position:0% +P4. Uh so I get to assume more. So this + + + align:start position:0% +P4. Uh so I get to assume more. So this +only makes my proof easier. + + align:start position:0% + + + + align:start position:0% + +Okay. Um to be clear, uh this is usually + + align:start position:0% +Okay. Um to be clear, uh this is usually + + + align:start position:0% +Okay. Um to be clear, uh this is usually +proved in cases normally you need to uh + + align:start position:0% +proved in cases normally you need to uh + + + align:start position:0% +proved in cases normally you need to uh +check zero specially. That might be a + + align:start position:0% +check zero specially. That might be a + + + align:start position:0% +check zero specially. That might be a +base case. Maybe you have to check one + + align:start position:0% +base case. Maybe you have to check one + + + align:start position:0% +base case. Maybe you have to check one +specially. It depends on your + + align:start position:0% +specially. It depends on your + + + align:start position:0% +specially. It depends on your +implication argument. this uh often this + + align:start position:0% +implication argument. this uh often this + + + align:start position:0% +implication argument. this uh often this +implication + + align:start position:0% +implication + + + align:start position:0% +implication +assumes that n is at least something and + + align:start position:0% +assumes that n is at least something and + + + align:start position:0% +assumes that n is at least something and +then you have to prove all the smaller + + align:start position:0% +then you have to prove all the smaller + + + align:start position:0% +then you have to prove all the smaller +ns to be true specially but we'll we'll + + align:start position:0% +ns to be true specially but we'll we'll + + + align:start position:0% +ns to be true specially but we'll we'll +get to examples in a moment. What I'd + + align:start position:0% +get to examples in a moment. What I'd + + + align:start position:0% +get to examples in a moment. What I'd +like to do first is actually prove that + + align:start position:0% +like to do first is actually prove that + + + align:start position:0% +like to do first is actually prove that +strong induction is true. + + align:start position:0% +strong induction is true. + + + align:start position:0% +strong induction is true. +This is not something you would repeat + + align:start position:0% +This is not something you would repeat + + + align:start position:0% +This is not something you would repeat +in your homework. You should just assume + + align:start position:0% +in your homework. You should just assume + + + align:start position:0% +in your homework. You should just assume +strong induction is true. But I think + + align:start position:0% +strong induction is true. But I think + + + align:start position:0% +strong induction is true. But I think +it's instructive to see why it's true + + align:start position:0% +it's instructive to see why it's true + + + align:start position:0% +it's instructive to see why it's true +as yet another example of induction. + + align:start position:0% +as yet another example of induction. + + + align:start position:0% +as yet another example of induction. +Okay, so we're going to use regular + + align:start position:0% +Okay, so we're going to use regular + + + align:start position:0% +Okay, so we're going to use regular +induction this version or actually I + + align:start position:0% +induction this version or actually I + + + align:start position:0% +induction this version or actually I +think this version the induction axiom + + align:start position:0% +think this version the induction axiom + + + align:start position:0% +think this version the induction axiom +uh to prove strong induction. + + align:start position:0% +uh to prove strong induction. + + + align:start position:0% +uh to prove strong induction. +Okay. Now, this is a situation where we + + align:start position:0% +Okay. Now, this is a situation where we + + + align:start position:0% +Okay. Now, this is a situation where we +need to define a particular induction + + align:start position:0% +need to define a particular induction + + + align:start position:0% +need to define a particular induction +hypothesis. This not the obvious one + + align:start position:0% + + + + align:start position:0% + +and this is not at all obvious, but I'm + + align:start position:0% +and this is not at all obvious, but I'm + + + align:start position:0% +and this is not at all obvious, but I'm +going to define uh IH of N to be uh this + + align:start position:0% +going to define uh IH of N to be uh this + + + align:start position:0% +going to define uh IH of N to be uh this +P of 0 and P of N minus one. In other + + align:start position:0% +P of 0 and P of N minus one. In other + + + align:start position:0% +P of 0 and P of N minus one. In other +words, uh for all I less than N, P of I. + + align:start position:0% +words, uh for all I less than N, P of I. + + + align:start position:0% +words, uh for all I less than N, P of I. +I like that better because it works even + + align:start position:0% +I like that better because it works even + + + align:start position:0% +I like that better because it works even +when n is zero because there are no i's + + align:start position:0% +when n is zero because there are no i's + + + align:start position:0% +when n is zero because there are no i's +less than zero. So that's just true when + + align:start position:0% +less than zero. So that's just true when + + + align:start position:0% +less than zero. So that's just true when +I when n is zero. Okay, so this is the + + align:start position:0% +I when n is zero. Okay, so this is the + + + align:start position:0% +I when n is zero. Okay, so this is the +thing I want to prove for all n. + + align:start position:0% +thing I want to prove for all n. + + + align:start position:0% +thing I want to prove for all n. +And how do we do it? Well, uh as usual + + align:start position:0% +And how do we do it? Well, uh as usual + + + align:start position:0% +And how do we do it? Well, uh as usual +with an induction, we have a base case. + + align:start position:0% +with an induction, we have a base case. + + + align:start position:0% +with an induction, we have a base case. +Base case is ih of zero. + + align:start position:0% +Base case is ih of zero. + + + align:start position:0% +Base case is ih of zero. +So uh ih of zero is actually literally + + align:start position:0% +So uh ih of zero is actually literally + + + align:start position:0% +So uh ih of zero is actually literally +just true. + + align:start position:0% +just true. + + + align:start position:0% +just true. +uh because we defined it to be that way. + + align:start position:0% +uh because we defined it to be that way. + + + align:start position:0% +uh because we defined it to be that way. +We said when n equals 0 this dot dot dot + + align:start position:0% +We said when n equals 0 this dot dot dot + + + align:start position:0% +We said when n equals 0 this dot dot dot +is true or you could say uh this is + + align:start position:0% +is true or you could say uh this is + + + align:start position:0% +is true or you could say uh this is +saying for all i less than zero where i + + align:start position:0% +saying for all i less than zero where i + + + align:start position:0% +saying for all i less than zero where i +is a natural number but there are no + + align:start position:0% +is a natural number but there are no + + + align:start position:0% +is a natural number but there are no +natural numbers less than zero. So this + + align:start position:0% +natural numbers less than zero. So this + + + align:start position:0% +natural numbers less than zero. So this +is like saying if false then something + + align:start position:0% +is like saying if false then something + + + align:start position:0% +is like saying if false then something +and that's just always true. So this is + + align:start position:0% +and that's just always true. So this is + + + align:start position:0% +and that's just always true. So this is +by definition + + align:start position:0% + + + + align:start position:0% + +uh ih of z is true. Great easy base case + + align:start position:0% +uh ih of z is true. Great easy base case + + + align:start position:0% +uh ih of z is true. Great easy base case +as usual. Uh what's the induction step + + align:start position:0% +as usual. Uh what's the induction step + + + align:start position:0% +as usual. Uh what's the induction step +look like? I'm going to I get to choose. + + align:start position:0% +look like? I'm going to I get to choose. + + + align:start position:0% +look like? I'm going to I get to choose. +I could either assume I of N minus one + + align:start position:0% +I could either assume I of N minus one + + + align:start position:0% +I could either assume I of N minus one +and prove IH of N or I'm going to assume + + align:start position:0% +and prove IH of N or I'm going to assume + + + align:start position:0% +and prove IH of N or I'm going to assume +I of N and uh prove uh IH of N + one. So + + align:start position:0% +I of N and uh prove uh IH of N + one. So + + + align:start position:0% +I of N and uh prove uh IH of N + one. So +we want to show if N plus1 assuming IH + + align:start position:0% +we want to show if N plus1 assuming IH + + + align:start position:0% +we want to show if N plus1 assuming IH +of N. Uh + + align:start position:0% +of N. Uh + + + align:start position:0% +of N. Uh +cool. So the key thing is we get to + + align:start position:0% +cool. So the key thing is we get to + + + align:start position:0% +cool. So the key thing is we get to +assume this is true. The strong + + align:start position:0% +assume this is true. The strong + + + align:start position:0% +assume this is true. The strong +induction says if this then this. So + + align:start position:0% +induction says if this then this. So + + + align:start position:0% +induction says if this then this. So +we're assuming the if part we're + + align:start position:0% +we're assuming the if part we're + + + align:start position:0% +we're assuming the if part we're +assuming that if uh this implication + + align:start position:0% +assuming that if uh this implication + + + align:start position:0% +assuming that if uh this implication +and this thing here is exactly IH of N, + + align:start position:0% +and this thing here is exactly IH of N, + + + align:start position:0% +and this thing here is exactly IH of N, +right? So this says IH of N implies P of + + align:start position:0% +right? So this says IH of N implies P of + + + align:start position:0% +right? So this says IH of N implies P of +N. So we know + + align:start position:0% +N. So we know + + + align:start position:0% +N. So we know +IH ofN implies P of N. That's uh what + + align:start position:0% +IH ofN implies P of N. That's uh what + + + align:start position:0% +IH ofN implies P of N. That's uh what +we're get to assume in our theorem + + align:start position:0% +we're get to assume in our theorem + + + align:start position:0% +we're get to assume in our theorem +statement here. and we just assumed that + + align:start position:0% +statement here. and we just assumed that + + + align:start position:0% +statement here. and we just assumed that +IH of N is true. Therefore, P of N is + + align:start position:0% +IH of N is true. Therefore, P of N is + + + align:start position:0% +IH of N is true. Therefore, P of N is +true. + + align:start position:0% +true. + + + align:start position:0% +true. +Okay, but P of N was not what we wanted + + align:start position:0% +Okay, but P of N was not what we wanted + + + align:start position:0% +Okay, but P of N was not what we wanted +to prove. We wanted to prove IH of N + + align:start position:0% +to prove. We wanted to prove IH of N + + + align:start position:0% +to prove. We wanted to prove IH of N +plus1. So, what is IH of N plus1? + + align:start position:0% + + + + align:start position:0% + +Uh let's just expand out this definition + + align:start position:0% +Uh let's just expand out this definition + + + align:start position:0% +Uh let's just expand out this definition +here. It is P of zero or dot dot dot or + + align:start position:0% +here. It is P of zero or dot dot dot or + + + align:start position:0% +here. It is P of zero or dot dot dot or +P of N minus one or P of N because I've + + align:start position:0% +P of N minus one or P of N because I've + + + align:start position:0% +P of N minus one or P of N because I've +incremented N by one. This no longer + + align:start position:0% +incremented N by one. This no longer + + + align:start position:0% +incremented N by one. This no longer +ends at P of N minus one. It now ends at + + align:start position:0% +ends at P of N minus one. It now ends at + + + align:start position:0% +ends at P of N minus one. It now ends at +P of N. Okay, but this is almost what we + + align:start position:0% +P of N. Okay, but this is almost what we + + + align:start position:0% +P of N. Okay, but this is almost what we +had before. This is the induction + + align:start position:0% +had before. This is the induction + + + align:start position:0% +had before. This is the induction +hypothesis of N. That's this part + + align:start position:0% +hypothesis of N. That's this part + + + align:start position:0% +hypothesis of N. That's this part +or P of N, + + align:start position:0% +or P of N, + + + align:start position:0% +or P of N, +right? That's just formula manipulation. + + align:start position:0% +right? That's just formula manipulation. + + + align:start position:0% +right? That's just formula manipulation. +And this we assumed is true. IH of N is + + align:start position:0% +And this we assumed is true. IH of N is + + + align:start position:0% +And this we assumed is true. IH of N is +true. And P ofN we just proved is true. + + align:start position:0% +true. And P ofN we just proved is true. + + + align:start position:0% +true. And P ofN we just proved is true. +Sorry. Uh I wrote or here but I meant + + align:start position:0% +Sorry. Uh I wrote or here but I meant + + + align:start position:0% +Sorry. Uh I wrote or here but I meant +and everywhere. This is and + + align:start position:0% +and everywhere. This is and + + + align:start position:0% +and everywhere. This is and +and + + align:start position:0% +and + + + align:start position:0% +and +see even professors get the V's and + + align:start position:0% +see even professors get the V's and + + + align:start position:0% +see even professors get the V's and +wedges upside down. So I wrote it + + align:start position:0% +wedges upside down. So I wrote it + + + align:start position:0% +wedges upside down. So I wrote it +correctly here. It's the and of P 0 up + + align:start position:0% +correctly here. It's the and of P 0 up + + + align:start position:0% +correctly here. It's the and of P 0 up +to PN minus one. Here we have the end of + + align:start position:0% +to PN minus one. Here we have the end of + + + align:start position:0% +to PN minus one. Here we have the end of +P 0 up to PN. And so this is IH of N + + align:start position:0% +P 0 up to PN. And so this is IH of N + + + align:start position:0% +P 0 up to PN. And so this is IH of N +which we assumed was true by induction. + + align:start position:0% +which we assumed was true by induction. + + + align:start position:0% +which we assumed was true by induction. +and P ofn which we just proved using one + + align:start position:0% +and P ofn which we just proved using one + + + align:start position:0% +and P ofn which we just proved using one +induction step. Therefore, the and is + + align:start position:0% +induction step. Therefore, the and is + + + align:start position:0% +induction step. Therefore, the and is +also true. + + align:start position:0% + + + + align:start position:0% + +And I believe that's the end of the + + align:start position:0% +And I believe that's the end of the + + + align:start position:0% +And I believe that's the end of the +proof, + + align:start position:0% +proof, + + + align:start position:0% +proof, +right? I did a base case, I did a step. + + align:start position:0% +right? I did a base case, I did a step. + + + align:start position:0% +right? I did a base case, I did a step. +Oh, no. Quite not quite the answer. + + align:start position:0% +Oh, no. Quite not quite the answer. + + + align:start position:0% +Oh, no. Quite not quite the answer. +Sorry, there's one more step here + + align:start position:0% +Sorry, there's one more step here + + + align:start position:0% +Sorry, there's one more step here +uh which I will put over here. + + align:start position:0% + + + + align:start position:0% + +It's a good illustration and not + + align:start position:0% +It's a good illustration and not + + + align:start position:0% +It's a good illustration and not +skipping steps. Uh what did we actually + + align:start position:0% +skipping steps. Uh what did we actually + + + align:start position:0% +skipping steps. Uh what did we actually +prove by induction? We proved induction + + align:start position:0% +prove by induction? We proved induction + + + align:start position:0% +prove by induction? We proved induction +hypothesis of n is true for all n. So by + + align:start position:0% +hypothesis of n is true for all n. So by + + + align:start position:0% +hypothesis of n is true for all n. So by +induction + + align:start position:0% +induction + + + align:start position:0% +induction +like the regular old induction axiom + + align:start position:0% + + + + align:start position:0% + +uh for all natural numbers n uh + + align:start position:0% +uh for all natural numbers n uh + + + align:start position:0% +uh for all natural numbers n uh +induction hypothesis of n is true + + align:start position:0% +induction hypothesis of n is true + + + align:start position:0% +induction hypothesis of n is true +induction hypothesis of n is this thing + + align:start position:0% +induction hypothesis of n is this thing + + + align:start position:0% +induction hypothesis of n is this thing +but that's not what we wanted to prove. + + align:start position:0% +but that's not what we wanted to prove. + + + align:start position:0% +but that's not what we wanted to prove. +We wanted to prove p of n is true for + + align:start position:0% +We wanted to prove p of n is true for + + + align:start position:0% +We wanted to prove p of n is true for +all all n. uh but I can do some + + align:start position:0% +all all n. uh but I can do some + + + align:start position:0% +all all n. uh but I can do some +manipulation to make that what I want. + + align:start position:0% +manipulation to make that what I want. + + + align:start position:0% +manipulation to make that what I want. +So this is like saying for all n + + align:start position:0% + + + + align:start position:0% + +uh + + align:start position:0% +uh + + + align:start position:0% +uh +let's see actually probably this is + + align:start position:0% +let's see actually probably this is + + + align:start position:0% +let's see actually probably this is +nicer for all natural numbers + + align:start position:0% +nicer for all natural numbers + + + align:start position:0% +nicer for all natural numbers +uh ih of n plus one is true okay this is + + align:start position:0% +uh ih of n plus one is true okay this is + + + align:start position:0% +uh ih of n plus one is true okay this is +a shift it's actually a weaker shift + + align:start position:0% +a shift it's actually a weaker shift + + + align:start position:0% +a shift it's actually a weaker shift +this includes ih of zero this + + align:start position:0% +this includes ih of zero this + + + align:start position:0% +this includes ih of zero this +should not be greater than equal to this + + align:start position:0% +should not be greater than equal to this + + + align:start position:0% +should not be greater than equal to this +should be an element of uh this includes + + align:start position:0% +should be an element of uh this includes + + + align:start position:0% +should be an element of uh this includes +zero this doesn't this starts at one and + + align:start position:0% +zero this doesn't this starts at one and + + + align:start position:0% +zero this doesn't this starts at one and +it goes upwards But this is nice. Uh + + align:start position:0% +it goes upwards But this is nice. Uh + + + align:start position:0% +it goes upwards But this is nice. Uh +this so this implies this, right? Uh + + align:start position:0% +this so this implies this, right? Uh + + + align:start position:0% +this so this implies this, right? Uh +this is what we've shown. This is a + + align:start position:0% +this is what we've shown. This is a + + + align:start position:0% +this is what we've shown. This is a +weaker statement because I just threw + + align:start position:0% +weaker statement because I just threw + + + align:start position:0% +weaker statement because I just threw +away I of zero. I of zero wasn't + + align:start position:0% +away I of zero. I of zero wasn't + + + align:start position:0% +away I of zero. I of zero wasn't +interesting anyway. + + align:start position:0% +interesting anyway. + + + align:start position:0% +interesting anyway. +I of one uh includes inside of it. So + + align:start position:0% +I of one uh includes inside of it. So + + + align:start position:0% +I of one uh includes inside of it. So +it's an and of a bunch of things. But + + align:start position:0% +it's an and of a bunch of things. But + + + align:start position:0% +it's an and of a bunch of things. But +then the last term is P of N. + + align:start position:0% +then the last term is P of N. + + + align:start position:0% +then the last term is P of N. +Right? That's if I take Ih of N + one, + + align:start position:0% +Right? That's if I take Ih of N + one, + + + align:start position:0% +Right? That's if I take Ih of N + one, +the last term in is P of N. So it's also + + align:start position:0% +the last term in is P of N. So it's also + + + align:start position:0% +the last term in is P of N. So it's also +anded but uh if the and is true then + + align:start position:0% +anded but uh if the and is true then + + + align:start position:0% +anded but uh if the and is true then +every term is true and so therefore p of + + align:start position:0% +every term is true and so therefore p of + + + align:start position:0% +every term is true and so therefore p of +n is true for all n. Okay, so this was a + + align:start position:0% +n is true for all n. Okay, so this was a + + + align:start position:0% +n is true for all n. Okay, so this was a +final clean up after we did induction. + + align:start position:0% +final clean up after we did induction. + + + align:start position:0% +final clean up after we did induction. +We didn't quite get the statement we + + align:start position:0% +We didn't quite get the statement we + + + align:start position:0% +We didn't quite get the statement we +wanted because we used a more gen a + + align:start position:0% +wanted because we used a more gen a + + + align:start position:0% +wanted because we used a more gen a +different induction hypothesis than just + + align:start position:0% +different induction hypothesis than just + + + align:start position:0% +different induction hypothesis than just +p. Uh and then we needed to show that + + align:start position:0% +p. Uh and then we needed to show that + + + align:start position:0% +p. Uh and then we needed to show that +that implied p of n for all n. Okay, but + + align:start position:0% +that implied p of n for all n. Okay, but + + + align:start position:0% +that implied p of n for all n. Okay, but +it works. + + align:start position:0% +it works. + + + align:start position:0% +it works. +Cool. So now uh there should be no + + align:start position:0% +Cool. So now uh there should be no + + + align:start position:0% +Cool. So now uh there should be no +question about why strong induction is + + align:start position:0% +question about why strong induction is + + + align:start position:0% +question about why strong induction is +true assuming you believe this proof. Um + + align:start position:0% +true assuming you believe this proof. Um + + + align:start position:0% +true assuming you believe this proof. Um +you can draw a diagram. Uh it's a little + + align:start position:0% +you can draw a diagram. Uh it's a little + + + align:start position:0% +you can draw a diagram. Uh it's a little +trickier to do. Maybe I will show you uh + + align:start position:0% +trickier to do. Maybe I will show you uh + + + align:start position:0% +trickier to do. Maybe I will show you uh +in my handwritten notes + + align:start position:0% +in my handwritten notes + + + align:start position:0% +in my handwritten notes +here. + + align:start position:0% + + + + align:start position:0% + +Here is a block diagram for strong + + align:start position:0% +Here is a block diagram for strong + + + align:start position:0% +Here is a block diagram for strong +induction. + + align:start position:0% +induction. + + + align:start position:0% +induction. +uh it's harder to draw because you + + align:start position:0% +uh it's harder to draw because you + + + align:start position:0% +uh it's harder to draw because you +depend on so many things when I apply + + align:start position:0% +depend on so many things when I apply + + + align:start position:0% +depend on so many things when I apply +the fourth step here when I want to + + align:start position:0% +the fourth step here when I want to + + + align:start position:0% +the fourth step here when I want to +conclude P of four I assume all the + + align:start position:0% +conclude P of four I assume all the + + + align:start position:0% +conclude P of four I assume all the +previous PS so P 0 P1 P2 P3 they all + + align:start position:0% +previous PS so P 0 P1 P2 P3 they all + + + align:start position:0% +previous PS so P 0 P1 P2 P3 they all +feed into this box in the beginning it's + + align:start position:0% +feed into this box in the beginning it's + + + align:start position:0% +feed into this box in the beginning it's +very similar I apply a step I get P of 0 + + align:start position:0% +very similar I apply a step I get P of 0 + + + align:start position:0% +very similar I apply a step I get P of 0 +then I apply that P of 0 to a step I get + + align:start position:0% +then I apply that P of 0 to a step I get + + + align:start position:0% +then I apply that P of 0 to a step I get +P of one uh but then as I proceed I'm + + align:start position:0% +P of one uh but then as I proceed I'm + + + align:start position:0% +P of one uh but then as I proceed I'm +feeding more and more PI's into the step + + align:start position:0% +feeding more and more PI's into the step + + + align:start position:0% +feeding more and more PI's into the step +and it gives me one more pi. Okay, so + + align:start position:0% +and it gives me one more pi. Okay, so + + + align:start position:0% +and it gives me one more pi. Okay, so +it's a much more complicated diagram + + align:start position:0% +it's a much more complicated diagram + + + align:start position:0% +it's a much more complicated diagram +what's going on under the hood. But from + + align:start position:0% +what's going on under the hood. But from + + + align:start position:0% +what's going on under the hood. But from +a usage standpoint, it's it only helps + + align:start position:0% +a usage standpoint, it's it only helps + + + align:start position:0% +a usage standpoint, it's it only helps +you when you're trying to prove P of N. + + align:start position:0% +you when you're trying to prove P of N. + + + align:start position:0% +you when you're trying to prove P of N. +You don't just get to assume P of N + + align:start position:0% +You don't just get to assume P of N + + + align:start position:0% +You don't just get to assume P of N +minus one. You get to assume all the + + align:start position:0% +minus one. You get to assume all the + + + align:start position:0% +minus one. You get to assume all the +PI's uh where I is less than N. + + align:start position:0% +PI's uh where I is less than N. + + + align:start position:0% +PI's uh where I is less than N. +I forgot one part of the fourcolor + + align:start position:0% +I forgot one part of the fourcolor + + + align:start position:0% +I forgot one part of the fourcolor +theorem story which was when I was + + align:start position:0% +theorem story which was when I was + + + align:start position:0% +theorem story which was when I was +growing up I read a reprint of this + + align:start position:0% +growing up I read a reprint of this + + + align:start position:0% +growing up I read a reprint of this +article by Martin Gardner which turned + + align:start position:0% +article by Martin Gardner which turned + + + align:start position:0% +article by Martin Gardner which turned +out to be published on April fools but I + + align:start position:0% +out to be published on April fools but I + + + align:start position:0% +out to be published on April fools but I +didn't know it at the time uh and in at + + align:start position:0% +didn't know it at the time uh and in at + + + align:start position:0% +didn't know it at the time uh and in at +that in 1975 there was no proof of the + + align:start position:0% +that in 1975 there was no proof of the + + + align:start position:0% +that in 1975 there was no proof of the +fourcolor theorem Haken was I think one + + align:start position:0% +fourcolor theorem Haken was I think one + + + align:start position:0% +fourcolor theorem Haken was I think one +year later uh so at this point he + + align:start position:0% +year later uh so at this point he + + + align:start position:0% +year later uh so at this point he +published a joke saying in fact McGregor + + align:start position:0% +published a joke saying in fact McGregor + + + align:start position:0% +published a joke saying in fact McGregor +found this map which requires five + + align:start position:0% +found this map which requires five + + + align:start position:0% +found this map which requires five +colors I remember sitting trying to + + align:start position:0% +colors I remember sitting trying to + + + align:start position:0% +colors I remember sitting trying to +color it with with four colors and + + align:start position:0% +color it with with four colors and + + + align:start position:0% +color it with with four colors and +always failing. It's like, oh my gosh, + + align:start position:0% +always failing. It's like, oh my gosh, + + + align:start position:0% +always failing. It's like, oh my gosh, +fourcolor theorem isn't true. This is or + + align:start position:0% +fourcolor theorem isn't true. This is or + + + align:start position:0% +fourcolor theorem isn't true. This is or +fourcolor conjecture as it was called + + align:start position:0% +fourcolor conjecture as it was called + + + align:start position:0% +fourcolor conjecture as it was called +then isn't true. Isn't that amazing? But + + align:start position:0% +then isn't true. Isn't that amazing? But + + + align:start position:0% +then isn't true. Isn't that amazing? But +it was all a lie. In fact, you can + + align:start position:0% +it was all a lie. In fact, you can + + + align:start position:0% +it was all a lie. In fact, you can +fourcolor that map. Uh but it's is a + + align:start position:0% +fourcolor that map. Uh but it's is a + + + align:start position:0% +fourcolor that map. Uh but it's is a +very funny article. If you want to read + + align:start position:0% +very funny article. If you want to read + + + align:start position:0% +very funny article. If you want to read +it, it's in in the lecture notes or part + + align:start position:0% +it, it's in in the lecture notes or part + + + align:start position:0% +it, it's in in the lecture notes or part +of it is there all sorts of crazy things + + align:start position:0% +of it is there all sorts of crazy things + + + align:start position:0% +of it is there all sorts of crazy things +like oh it turns out if you take uh e + + align:start position:0% +like oh it turns out if you take uh e + + + align:start position:0% +like oh it turns out if you take uh e +and you raise it to pi time<unk> of 163, + + align:start position:0% +and you raise it to pi time<unk> of 163, + + + align:start position:0% +and you raise it to pi time<unk> of 163, +the result is an integer. + + align:start position:0% +the result is an integer. + + + align:start position:0% +the result is an integer. +It's not true. But, uh, all sorts of + + align:start position:0% +It's not true. But, uh, all sorts of + + + align:start position:0% +It's not true. But, uh, all sorts of +crazy things. Also, uh, chess has a + + align:start position:0% +crazy things. Also, uh, chess has a + + + align:start position:0% +crazy things. Also, uh, chess has a +crazy winning move. And anyway, + + align:start position:0% +crazy winning move. And anyway, + + + align:start position:0% +crazy winning move. And anyway, +uh, to relive the youth. All right. Um, + + align:start position:0% +uh, to relive the youth. All right. Um, + + + align:start position:0% +uh, to relive the youth. All right. Um, +I think I'd like to, uh, yeah, show you + + align:start position:0% +I think I'd like to, uh, yeah, show you + + + align:start position:0% +I think I'd like to, uh, yeah, show you +some examples of strong induction, but + + align:start position:0% +some examples of strong induction, but + + + align:start position:0% +some examples of strong induction, but +maybe first I should show you a template + + align:start position:0% +maybe first I should show you a template + + + align:start position:0% +maybe first I should show you a template +for applying induction. Strong + + align:start position:0% +for applying induction. Strong + + + align:start position:0% +for applying induction. Strong +induction. + + align:start position:0% + + + + align:start position:0% + +uh we'll repeat some of the things that + + align:start position:0% +uh we'll repeat some of the things that + + + align:start position:0% +uh we'll repeat some of the things that +I've said but I think it's good to have + + align:start position:0% +I've said but I think it's good to have + + + align:start position:0% +I've said but I think it's good to have +it concrete. + + align:start position:0% +it concrete. + + + align:start position:0% +it concrete. +So here is a template. + + align:start position:0% + + + + align:start position:0% + +Suppose you want to prove + + align:start position:0% +Suppose you want to prove + + + align:start position:0% +Suppose you want to prove +uh something is true for all natural + + align:start position:0% +uh something is true for all natural + + + align:start position:0% +uh something is true for all natural +numbers. So for all natural numbers n uh + + align:start position:0% +numbers. So for all natural numbers n uh + + + align:start position:0% +numbers. So for all natural numbers n uh +p of n is true. Then here's what the + + align:start position:0% +p of n is true. Then here's what the + + + align:start position:0% +p of n is true. Then here's what the +proof will look like. + + align:start position:0% +proof will look like. + + + align:start position:0% +proof will look like. +uh by proof by strong induction. + + align:start position:0% + + + + align:start position:0% + +Uh + + align:start position:0% +Uh + + + align:start position:0% +Uh +so generally we're assuming p of k uh + + align:start position:0% +so generally we're assuming p of k uh + + + align:start position:0% +so generally we're assuming p of k uh +for all k less than n + + align:start position:0% +for all k less than n + + + align:start position:0% +for all k less than n +and then we want to show p of n. + + align:start position:0% +and then we want to show p of n. + + + align:start position:0% +and then we want to show p of n. +Okay? Or you could shift the numbers by + + align:start position:0% +Okay? Or you could shift the numbers by + + + align:start position:0% +Okay? Or you could shift the numbers by +one but this is my preferred way of + + align:start position:0% +one but this is my preferred way of + + + align:start position:0% +one but this is my preferred way of +thinking about it. uh usually we prove + + align:start position:0% +thinking about it. uh usually we prove + + + align:start position:0% +thinking about it. uh usually we prove +this by cases + + align:start position:0% +this by cases + + + align:start position:0% +this by cases +which is the method we just saw. This is + + align:start position:0% +which is the method we just saw. This is + + + align:start position:0% +which is the method we just saw. This is +why we're pairing proof by cases with + + align:start position:0% +why we're pairing proof by cases with + + + align:start position:0% +why we're pairing proof by cases with +strong induction. How do we prove p of + + align:start position:0% +strong induction. How do we prove p of + + + align:start position:0% +strong induction. How do we prove p of +n? Well, it might depend. Often we have + + align:start position:0% +n? Well, it might depend. Often we have + + + align:start position:0% +n? Well, it might depend. Often we have +some base cases + + align:start position:0% +some base cases + + + align:start position:0% +some base cases +where n is small. + + align:start position:0% +where n is small. + + + align:start position:0% +where n is small. +So uh maybe we have to prove p of zero, + + align:start position:0% +So uh maybe we have to prove p of zero, + + + align:start position:0% +So uh maybe we have to prove p of zero, +maybe we have to prove p of one. Uh who + + align:start position:0% +maybe we have to prove p of one. Uh who + + + align:start position:0% +maybe we have to prove p of one. Uh who +knows? Let's say up to P of little B are + + align:start position:0% +knows? Let's say up to P of little B are + + + align:start position:0% +knows? Let's say up to P of little B are +the base cases. Maybe you have to prove + + align:start position:0% +the base cases. Maybe you have to prove + + + align:start position:0% +the base cases. Maybe you have to prove +those specially for some reason. + + align:start position:0% +those specially for some reason. + + + align:start position:0% +those specially for some reason. +Okay. Then we do an induction step. + + align:start position:0% + + + + align:start position:0% + +So I'll say by cases here. + + align:start position:0% +So I'll say by cases here. + + + align:start position:0% +So I'll say by cases here. +Uh induction step. We get to assume + + align:start position:0% +Uh induction step. We get to assume + + + align:start position:0% +Uh induction step. We get to assume +n is bigger than b because we just prove + + align:start position:0% +n is bigger than b because we just prove + + + align:start position:0% +n is bigger than b because we just prove +zero up to b manually. + + align:start position:0% +zero up to b manually. + + + align:start position:0% +zero up to b manually. +uh and then we need to prove in those + + align:start position:0% +uh and then we need to prove in those + + + align:start position:0% +uh and then we need to prove in those +scenarios p of n is true because + + align:start position:0% +scenarios p of n is true because + + + align:start position:0% +scenarios p of n is true because +uh reasons. + + align:start position:0% + + + + align:start position:0% + +Okay. But the the big thing here is we + + align:start position:0% +Okay. But the the big thing here is we + + + align:start position:0% +Okay. But the the big thing here is we +get to assume in in these reasons uh we + + align:start position:0% +get to assume in in these reasons uh we + + + align:start position:0% +get to assume in in these reasons uh we +get to use + + align:start position:0% +get to use + + + align:start position:0% +get to use +uh p 0 p1 + + align:start position:0% +uh p 0 p1 + + + align:start position:0% +uh p 0 p1 +up to p n minus one. + + align:start position:0% + + + + align:start position:0% + +Okay. So uh that's the big win. And in + + align:start position:0% +Okay. So uh that's the big win. And in + + + align:start position:0% +Okay. So uh that's the big win. And in +the base cases you don't I mean you also + + align:start position:0% +the base cases you don't I mean you also + + + align:start position:0% +the base cases you don't I mean you also +get to assume this but for example when + + align:start position:0% +get to assume this but for example when + + + align:start position:0% +get to assume this but for example when +you're proving P 0 you don't really get + + align:start position:0% +you're proving P 0 you don't really get + + + align:start position:0% +you're proving P 0 you don't really get +to assume anything because there are no + + align:start position:0% +to assume anything because there are no + + + align:start position:0% +to assume anything because there are no +smaller pis. Uh so often you have to do + + align:start position:0% +smaller pis. Uh so often you have to do + + + align:start position:0% +smaller pis. Uh so often you have to do +these specially because the induction + + align:start position:0% +these specially because the induction + + + align:start position:0% +these specially because the induction +step assumes somehow that n is bigger + + align:start position:0% +step assumes somehow that n is bigger + + + align:start position:0% +step assumes somehow that n is bigger +than zero. + + align:start position:0% +than zero. + + + align:start position:0% +than zero. +Sometimes you get lucky you just need + + align:start position:0% +Sometimes you get lucky you just need + + + align:start position:0% +Sometimes you get lucky you just need +the induction step but usually you need + + align:start position:0% +the induction step but usually you need + + + align:start position:0% +the induction step but usually you need +base cases. Let's see some examples and + + align:start position:0% +base cases. Let's see some examples and + + + align:start position:0% +base cases. Let's see some examples and +this will become much clearer. + + align:start position:0% +this will become much clearer. + + + align:start position:0% +this will become much clearer. +So let's play a game. + + align:start position:0% + + + + align:start position:0% + +called item stacking + + align:start position:0% + + + + align:start position:0% + +or it's really unstacking. + + align:start position:0% + + + + align:start position:0% + +So this is + + align:start position:0% + + + + align:start position:0% + +unstacking game. + + align:start position:0% + + + + align:start position:0% + +So, we're going to start with + + align:start position:0% +So, we're going to start with + + + align:start position:0% +So, we're going to start with +one stack + + align:start position:0% +one stack + + + align:start position:0% +one stack +of n + + align:start position:0% +of n + + + align:start position:0% +of n +and then a move + + align:start position:0% +and then a move + + + align:start position:0% +and then a move +uh splits + + align:start position:0% + + + + align:start position:0% + +uh + + align:start position:0% +uh + + + align:start position:0% +uh +stack + + align:start position:0% +stack + + + align:start position:0% +stack +of s bigger than one items. + + align:start position:0% + + + + align:start position:0% + +into + + align:start position:0% +into + + + align:start position:0% +into +two stacks + + align:start position:0% + + + + align:start position:0% + +with A items in one and B items in the + + align:start position:0% +with A items in one and B items in the + + + align:start position:0% +with A items in one and B items in the +other. + + align:start position:0% + + + + align:start position:0% + +And you get to choose these numbers A + + align:start position:0% +And you get to choose these numbers A + + + align:start position:0% +And you get to choose these numbers A +and B, but you need conservation. So A + + align:start position:0% +and B, but you need conservation. So A + + + align:start position:0% +and B, but you need conservation. So A +plus B has to equal S. + + align:start position:0% +plus B has to equal S. + + + align:start position:0% +plus B has to equal S. +And uh we also don't want zero height + + align:start position:0% +And uh we also don't want zero height + + + align:start position:0% +And uh we also don't want zero height +stack. So we need A at least one and B + + align:start position:0% +stack. So we need A at least one and B + + + align:start position:0% +stack. So we need A at least one and B +at least one. Okay. So you get to choose + + align:start position:0% +at least one. Okay. So you get to choose + + + align:start position:0% +at least one. Okay. So you get to choose +A and B however you want so long as + + align:start position:0% +A and B however you want so long as + + + align:start position:0% +A and B however you want so long as +there's at least one item in each stack. + + align:start position:0% +there's at least one item in each stack. + + + align:start position:0% +there's at least one item in each stack. +So let's take a physical example + + align:start position:0% + + + + align:start position:0% + +and got lots of blocks here, but I have + + align:start position:0% +and got lots of blocks here, but I have + + + align:start position:0% +and got lots of blocks here, but I have +no audience, so we're just going to demo + + align:start position:0% +no audience, so we're just going to demo + + + align:start position:0% +no audience, so we're just going to demo +this myself in in real life. Uh this is + + align:start position:0% +this myself in in real life. Uh this is + + + align:start position:0% +this myself in in real life. Uh this is +actually this was a snow day at MIT and + + align:start position:0% +actually this was a snow day at MIT and + + + align:start position:0% +actually this was a snow day at MIT and +so we're recording after the fact. So + + align:start position:0% +so we're recording after the fact. So + + + align:start position:0% +so we're recording after the fact. So +all the students MIT students have seen + + align:start position:0% +all the students MIT students have seen + + + align:start position:0% +all the students MIT students have seen +it. This is specially for you at OCW. + + align:start position:0% +it. This is specially for you at OCW. + + + align:start position:0% +it. This is specially for you at OCW. +Uh so when we do a move uh from S. So + + align:start position:0% +Uh so when we do a move uh from S. So + + + align:start position:0% +Uh so when we do a move uh from S. So +this is we have a stack of size S and we + + align:start position:0% +this is we have a stack of size S and we + + + align:start position:0% +this is we have a stack of size S and we +convert it into a stack of size A and a + + align:start position:0% +convert it into a stack of size A and a + + + align:start position:0% +convert it into a stack of size A and a +stack of size B. We get A time B points. + + align:start position:0% + + + + align:start position:0% + +That's just the definition of the game. + + align:start position:0% +That's just the definition of the game. + + + align:start position:0% +That's just the definition of the game. +A* B points. When you split into a stack + + align:start position:0% +A* B points. When you split into a stack + + + align:start position:0% +A* B points. When you split into a stack +of size A and a stack of size B. Uh so + + align:start position:0% +of size A and a stack of size B. Uh so + + + align:start position:0% +of size A and a stack of size B. Uh so +how should I maximize my score in this + + align:start position:0% +how should I maximize my score in this + + + align:start position:0% +how should I maximize my score in this +game? What's the best strategy? Uh the + + align:start position:0% +game? What's the best strategy? Uh the + + + align:start position:0% +game? What's the best strategy? Uh the +game ends when all your stacks have size + + align:start position:0% +game ends when all your stacks have size + + + align:start position:0% +game ends when all your stacks have size +one because you can't make a move on a + + align:start position:0% +one because you can't make a move on a + + + align:start position:0% +one because you can't make a move on a +stack of one item. It has to be greater + + align:start position:0% +stack of one item. It has to be greater + + + align:start position:0% +stack of one item. It has to be greater +than one items. So let's try here. I + + align:start position:0% +than one items. So let's try here. I + + + align:start position:0% +than one items. So let's try here. I +have a stack of five blocks. + + align:start position:0% +have a stack of five blocks. + + + align:start position:0% +have a stack of five blocks. +And uh one thing maybe I'll try to split + + align:start position:0% +And uh one thing maybe I'll try to split + + + align:start position:0% +And uh one thing maybe I'll try to split +it roughly in the middle. So now here + + align:start position:0% +it roughly in the middle. So now here + + + align:start position:0% +it roughly in the middle. So now here +I'll rotate this so you can see the + + align:start position:0% +I'll rotate this so you can see the + + + align:start position:0% +I'll rotate this so you can see the +blocks a little bigger. Uh these are + + align:start position:0% +blocks a little bigger. Uh these are + + + align:start position:0% +blocks a little bigger. Uh these are +five blocks. uh I split like this. So + + align:start position:0% +five blocks. uh I split like this. So + + + align:start position:0% +five blocks. uh I split like this. So +that's a I group of two and a group of + + align:start position:0% +that's a I group of two and a group of + + + align:start position:0% +that's a I group of two and a group of +three. Product of two * three is six. I + + align:start position:0% +three. Product of two * three is six. I + + + align:start position:0% +three. Product of two * three is six. I +can do this level of arithmetic. So six + + align:start position:0% +can do this level of arithmetic. So six + + + align:start position:0% +can do this level of arithmetic. So six +is our total so far. When I split this + + align:start position:0% +is our total so far. When I split this + + + align:start position:0% +is our total so far. When I split this +one, I get one more point. That's seven. + + align:start position:0% +one, I get one more point. That's seven. + + + align:start position:0% +one, I get one more point. That's seven. +When I split this one, doesn't matter + + align:start position:0% +When I split this one, doesn't matter + + + align:start position:0% +When I split this one, doesn't matter +how I do it, I get uh 2 * 1. So that's + + align:start position:0% +how I do it, I get uh 2 * 1. So that's + + + align:start position:0% +how I do it, I get uh 2 * 1. So that's +two more points. That's nine. And when I + + align:start position:0% +two more points. That's nine. And when I + + + align:start position:0% +two more points. That's nine. And when I +split this group, I get one more point. + + align:start position:0% +split this group, I get one more point. + + + align:start position:0% +split this group, I get one more point. +That's 10. Okay. So one approach gives + + align:start position:0% +That's 10. Okay. So one approach gives + + + align:start position:0% +That's 10. Okay. So one approach gives +me 10 points. What if another natural + + align:start position:0% +me 10 points. What if another natural + + + align:start position:0% +me 10 points. What if another natural +strategy that was like splitting in the + + align:start position:0% +strategy that was like splitting in the + + + align:start position:0% +strategy that was like splitting in the +middle? Another natural strategy is I + + align:start position:0% +middle? Another natural strategy is I + + + align:start position:0% +middle? Another natural strategy is I +just take one off each time. So if I + + align:start position:0% +just take one off each time. So if I + + + align:start position:0% +just take one off each time. So if I +take one off here, I get four points. Uh + + align:start position:0% +take one off here, I get four points. Uh + + + align:start position:0% +take one off here, I get four points. Uh +if I take one more off, I get three more + + align:start position:0% +if I take one more off, I get three more + + + align:start position:0% +if I take one more off, I get three more +points. That's seven. 4 + 3 is seven. I + + align:start position:0% +points. That's seven. 4 + 3 is seven. I + + + align:start position:0% +points. That's seven. 4 + 3 is seven. I +take one more off, I get two points, + + align:start position:0% +take one more off, I get two points, + + + align:start position:0% +take one more off, I get two points, +that's nine. I take one more off, that's + + align:start position:0% +that's nine. I take one more off, that's + + + align:start position:0% +that's nine. I take one more off, that's +one point, that's 10. Huh? 10 points + + align:start position:0% +one point, that's 10. Huh? 10 points + + + align:start position:0% +one point, that's 10. Huh? 10 points +that way, 10 points the other way as + + align:start position:0% +that way, 10 points the other way as + + + align:start position:0% +that way, 10 points the other way as +well. Maybe there's a theorem here. + + align:start position:0% +well. Maybe there's a theorem here. + + + align:start position:0% +well. Maybe there's a theorem here. +Maybe no matter what I do, I get 10 + + align:start position:0% +Maybe no matter what I do, I get 10 + + + align:start position:0% +Maybe no matter what I do, I get 10 +points. Well, that won't be true. But + + align:start position:0% +points. Well, that won't be true. But + + + align:start position:0% +points. Well, that won't be true. But +for five blocks, I will always get 10 + + align:start position:0% +for five blocks, I will always get 10 + + + align:start position:0% +for five blocks, I will always get 10 +points. For six blocks, I will always + + align:start position:0% +points. For six blocks, I will always + + + align:start position:0% +points. For six blocks, I will always +get, I don't know, 15, some more points. + + align:start position:0% +get, I don't know, 15, some more points. + + + align:start position:0% +get, I don't know, 15, some more points. +Uh, it turns out it doesn't matter what + + align:start position:0% +Uh, it turns out it doesn't matter what + + + align:start position:0% +Uh, it turns out it doesn't matter what +strategy you follow, you always get the + + align:start position:0% +strategy you follow, you always get the + + + align:start position:0% +strategy you follow, you always get the +same number of points for a given + + align:start position:0% +same number of points for a given + + + align:start position:0% +same number of points for a given +initial stack of size n. + + align:start position:0% +initial stack of size n. + + + align:start position:0% +initial stack of size n. +Let's prove that with strong induction. + + align:start position:0% + + + + align:start position:0% + +Okay. So theorem is + + align:start position:0% + + + + align:start position:0% + +for all natural numbers + + align:start position:0% +for all natural numbers + + + align:start position:0% +for all natural numbers +uh + + align:start position:0% +uh + + + align:start position:0% +uh +every strategy + + align:start position:0% +every strategy + + + align:start position:0% +every strategy +for this game. + + align:start position:0% +for this game. + + + align:start position:0% +for this game. +Uh starting + + align:start position:0% + + + + align:start position:0% + +uh with the stack one stack of n items + + align:start position:0% + + + + align:start position:0% + +scores + + align:start position:0% +scores + + + align:start position:0% +scores +magic formula is n * n minus one over 2. + + align:start position:0% + + + + align:start position:0% + +So that's the theorem and we're going to + + align:start position:0% +So that's the theorem and we're going to + + + align:start position:0% +So that's the theorem and we're going to +prove it by strong induction + + align:start position:0% + + + + align:start position:0% + +in sort of the straightforward way. So + + align:start position:0% +in sort of the straightforward way. So + + + align:start position:0% +in sort of the straightforward way. So +our induction hypothesis is going to be + + align:start position:0% +our induction hypothesis is going to be + + + align:start position:0% +our induction hypothesis is going to be +exactly the theorem statement uh for a + + align:start position:0% +exactly the theorem statement uh for a + + + align:start position:0% +exactly the theorem statement uh for a +particular n. So I'm going to highlight + + align:start position:0% +particular n. So I'm going to highlight + + + align:start position:0% +particular n. So I'm going to highlight +this + + align:start position:0% +this + + + align:start position:0% +this +statement everything except the + + align:start position:0% +statement everything except the + + + align:start position:0% +statement everything except the +quantifier and I'll call that p of n. So + + align:start position:0% +quantifier and I'll call that p of n. So + + + align:start position:0% +quantifier and I'll call that p of n. So +what I want to prove is for all natural + + align:start position:0% +what I want to prove is for all natural + + + align:start position:0% +what I want to prove is for all natural +numbers n P of N is true. And so that's + + align:start position:0% +numbers n P of N is true. And so that's + + + align:start position:0% +numbers n P of N is true. And so that's +that's just going to be our induction + + align:start position:0% +that's just going to be our induction + + + align:start position:0% +that's just going to be our induction +hypothesis. We're going to plug that + + align:start position:0% +hypothesis. We're going to plug that + + + align:start position:0% +hypothesis. We're going to plug that +into this template here. Assume that P + + align:start position:0% +into this template here. Assume that P + + + align:start position:0% +into this template here. Assume that P +of K is true for all K less than N and + + align:start position:0% +of K is true for all K less than N and + + + align:start position:0% +of K is true for all K less than N and +then prove P of N is true. So let's just + + align:start position:0% +then prove P of N is true. So let's just + + + align:start position:0% +then prove P of N is true. So let's just +try to do that. + + align:start position:0% +try to do that. + + + align:start position:0% +try to do that. +So what I would normally write here is + + align:start position:0% +So what I would normally write here is + + + align:start position:0% +So what I would normally write here is +assume + + align:start position:0% +assume + + + align:start position:0% +assume +true assume that my theorem is true. + + align:start position:0% +true assume that my theorem is true. + + + align:start position:0% +true assume that my theorem is true. +Assume P of N is true. uh sorry p of k + + align:start position:0% +Assume P of N is true. uh sorry p of k + + + align:start position:0% +Assume P of N is true. uh sorry p of k +is true for all k less than n. I would + + align:start position:0% +is true for all k less than n. I would + + + align:start position:0% +is true for all k less than n. I would +say assume true for all smaller n. + + align:start position:0% + + + + align:start position:0% + +Okay, let's uh we need to do something + + align:start position:0% +Okay, let's uh we need to do something + + + align:start position:0% +Okay, let's uh we need to do something +with the game. We start with a pile of + + align:start position:0% +with the game. We start with a pile of + + + align:start position:0% +with the game. We start with a pile of +size n. Let's just think about the first + + align:start position:0% +size n. Let's just think about the first + + + align:start position:0% +size n. Let's just think about the first +move. + + align:start position:0% +move. + + + align:start position:0% +move. +First move is something. It's takes our + + align:start position:0% +First move is something. It's takes our + + + align:start position:0% +First move is something. It's takes our +pile of size n and it splits it into + + align:start position:0% +pile of size n and it splits it into + + + align:start position:0% +pile of size n and it splits it into +some piles a and b. + + align:start position:0% +some piles a and b. + + + align:start position:0% +some piles a and b. +So uh we don't know what it is. We don't + + align:start position:0% +So uh we don't know what it is. We don't + + + align:start position:0% +So uh we don't know what it is. We don't +know what a and b are. But we can give + + align:start position:0% +know what a and b are. But we can give + + + align:start position:0% +know what a and b are. But we can give +them a name. Like this has to work no + + align:start position:0% +them a name. Like this has to work no + + + align:start position:0% +them a name. Like this has to work no +matter what a and b are. But let's say + + align:start position:0% +matter what a and b are. But let's say + + + align:start position:0% +matter what a and b are. But let's say +consider first move which we know we + + align:start position:0% +consider first move which we know we + + + align:start position:0% +consider first move which we know we +start with a pile of size n. And we + + align:start position:0% +start with a pile of size n. And we + + + align:start position:0% +start with a pile of size n. And we +produce piles of size a and b. And again + + align:start position:0% +produce piles of size a and b. And again + + + align:start position:0% +produce piles of size a and b. And again +uh a + b equals n and a and b are at + + align:start position:0% +uh a + b equals n and a and b are at + + + align:start position:0% +uh a + b equals n and a and b are at +least one. But otherwise we don't know + + align:start position:0% +least one. But otherwise we don't know + + + align:start position:0% +least one. But otherwise we don't know +what a and b are. + + align:start position:0% + + + + align:start position:0% + +Okay, + + align:start position:0% +Okay, + + + align:start position:0% +Okay, +so we go down to here. Um, + + align:start position:0% +so we go down to here. Um, + + + align:start position:0% +so we go down to here. Um, +so we now have a pile of size A and we + + align:start position:0% +so we now have a pile of size A and we + + + align:start position:0% +so we now have a pile of size A and we +have a pile of size B. Again, we don't + + align:start position:0% +have a pile of size B. Again, we don't + + + align:start position:0% +have a pile of size B. Again, we don't +know how big they are, but they are + + align:start position:0% +know how big they are, but they are + + + align:start position:0% +know how big they are, but they are +smaller than B. So I want to claim we + + align:start position:0% +smaller than B. So I want to claim we + + + align:start position:0% +smaller than B. So I want to claim we +are uh left + + align:start position:0% +are uh left + + + align:start position:0% +are uh left +with two piles or we can really think of + + align:start position:0% +with two piles or we can really think of + + + align:start position:0% +with two piles or we can really think of +those as two completely separate games + + align:start position:0% +those as two completely separate games + + + align:start position:0% +those as two completely separate games +A and B. We're going to get some points + + align:start position:0% +A and B. We're going to get some points + + + align:start position:0% +A and B. We're going to get some points +from splitting up A. We're going to get + + align:start position:0% +from splitting up A. We're going to get + + + align:start position:0% +from splitting up A. We're going to get +some points from splitting up B. They + + align:start position:0% +some points from splitting up B. They + + + align:start position:0% +some points from splitting up B. They +sum together, but the these piles don't + + align:start position:0% +sum together, but the these piles don't + + + align:start position:0% +sum together, but the these piles don't +really interact from here on. We got uh + + align:start position:0% +really interact from here on. We got uh + + + align:start position:0% +really interact from here on. We got uh +we got A* B points from this first step. + + align:start position:0% +we got A* B points from this first step. + + + align:start position:0% +we got A* B points from this first step. +We're going to get some points from the + + align:start position:0% +We're going to get some points from the + + + align:start position:0% +We're going to get some points from the +pile of size A. We're going to get some + + align:start position:0% +pile of size A. We're going to get some + + + align:start position:0% +pile of size A. We're going to get some +points to the pile of size B. How many + + align:start position:0% +points to the pile of size B. How many + + + align:start position:0% +points to the pile of size B. How many +points do we get? Uh well, in fact, our + + align:start position:0% +points do we get? Uh well, in fact, our + + + align:start position:0% +points do we get? Uh well, in fact, our +induction hypothesis will tell us + + align:start position:0% +induction hypothesis will tell us + + + align:start position:0% +induction hypothesis will tell us +because + + align:start position:0% +because + + + align:start position:0% +because +uh A and B are strictly less than N. + + align:start position:0% +uh A and B are strictly less than N. + + + align:start position:0% +uh A and B are strictly less than N. +Why? Because + + align:start position:0% +Why? Because + + + align:start position:0% +Why? Because +uh a + b= n and a and b are at least + + align:start position:0% +uh a + b= n and a and b are at least + + + align:start position:0% +uh a + b= n and a and b are at least +one. + + align:start position:0% + + + + align:start position:0% + +So there's at least one in each of a and + + align:start position:0% +So there's at least one in each of a and + + + align:start position:0% +So there's at least one in each of a and +b. And so the remainder must be strictly + + align:start position:0% +b. And so the remainder must be strictly + + + align:start position:0% +b. And so the remainder must be strictly +less than n. If there's one in a, then + + align:start position:0% +less than n. If there's one in a, then + + + align:start position:0% +less than n. If there's one in a, then +there'll be n minus one in b. If there's + + align:start position:0% +there'll be n minus one in b. If there's + + + align:start position:0% +there'll be n minus one in b. If there's +two in a, there'll be n minus two in b. + + align:start position:0% +two in a, there'll be n minus two in b. + + + align:start position:0% +two in a, there'll be n minus two in b. +In all cases, less than n. Okay? Because + + align:start position:0% +In all cases, less than n. Okay? Because + + + align:start position:0% +In all cases, less than n. Okay? Because +a and b are less than n, they're not + + align:start position:0% +a and b are less than n, they're not + + + align:start position:0% +a and b are less than n, they're not +just they're not necessarily n minus + + align:start position:0% +just they're not necessarily n minus + + + align:start position:0% +just they're not necessarily n minus +one. So we couldn't just use regular + + align:start position:0% +one. So we couldn't just use regular + + + align:start position:0% +one. So we couldn't just use regular +induction. But we have they're less than + + align:start position:0% +induction. But we have they're less than + + + align:start position:0% +induction. But we have they're less than +n. And so by strong induction + + align:start position:0% +n. And so by strong induction + + + align:start position:0% +n. And so by strong induction +uh by strong induction + + align:start position:0% +uh by strong induction + + + align:start position:0% +uh by strong induction +we know that P of A is true and P of B + + align:start position:0% +we know that P of A is true and P of B + + + align:start position:0% +we know that P of A is true and P of B +is true. + + align:start position:0% + + + + align:start position:0% + +Okay, we wrote that up here. So P of K + + align:start position:0% +Okay, we wrote that up here. So P of K + + + align:start position:0% +Okay, we wrote that up here. So P of K +for all K less than N. So A and B are + + align:start position:0% +for all K less than N. So A and B are + + + align:start position:0% +for all K less than N. So A and B are +less than N. So P of A is true and P of + + align:start position:0% +less than N. So P of A is true and P of + + + align:start position:0% +less than N. So P of A is true and P of +B are is true. So that means from the + + align:start position:0% +B are is true. So that means from the + + + align:start position:0% +B are is true. So that means from the +pile of size a + + align:start position:0% +pile of size a + + + align:start position:0% +pile of size a +we get uh a * a minus1 / 2 points + + align:start position:0% + + + + align:start position:0% + +from the a pile. We get b * b minus one + + align:start position:0% +from the a pile. We get b * b minus one + + + align:start position:0% +from the a pile. We get b * b minus one +over two points from the b pile. + + align:start position:0% + + + + align:start position:0% + +And then of course we got a time b move + + align:start position:0% +And then of course we got a time b move + + + align:start position:0% +And then of course we got a time b move +points uh from the first move. + + align:start position:0% + + + + align:start position:0% + +And so now we just need to do some + + align:start position:0% +And so now we just need to do some + + + align:start position:0% +And so now we just need to do some +algebra and add up all these points. + + align:start position:0% +algebra and add up all these points. + + + align:start position:0% +algebra and add up all these points. +So the total number of points that we + + align:start position:0% +So the total number of points that we + + + align:start position:0% +So the total number of points that we +get is a * b + a * a -1 / 2 plus b * b - + + align:start position:0% +get is a * b + a * a -1 / 2 plus b * b - + + + align:start position:0% +get is a * b + a * a -1 / 2 plus b * b - +1 / 2 + + align:start position:0% +1 / 2 + + + align:start position:0% +1 / 2 +These two were by induction. This was + + align:start position:0% +These two were by induction. This was + + + align:start position:0% +These two were by induction. This was +the first move. Uh, and now let's just + + align:start position:0% +the first move. Uh, and now let's just + + + align:start position:0% +the first move. Uh, and now let's just +put everything over two. So this is 2 * + + align:start position:0% +put everything over two. So this is 2 * + + + align:start position:0% +put everything over two. So this is 2 * +a * b plus I don't know a^ 2 - a + b ^ 2 + + align:start position:0% +a * b plus I don't know a^ 2 - a + b ^ 2 + + + align:start position:0% +a * b plus I don't know a^ 2 - a + b ^ 2 +- b all over two. + + align:start position:0% +- b all over two. + + + align:start position:0% +- b all over two. +Okay. And now what do I want to get to? + + align:start position:0% +Okay. And now what do I want to get to? + + + align:start position:0% +Okay. And now what do I want to get to? +This is supposed to equal n * n minus + + align:start position:0% +This is supposed to equal n * n minus + + + align:start position:0% +This is supposed to equal n * n minus +one over two. And what was n? n was a + + align:start position:0% +one over two. And what was n? n was a + + + align:start position:0% +one over two. And what was n? n was a +plus b. + + align:start position:0% +plus b. + + + align:start position:0% +plus b. +So, what I'd really like to show here is + + align:start position:0% +So, what I'd really like to show here is + + + align:start position:0% +So, what I'd really like to show here is +uh a + b * a + b minus one over two. + + align:start position:0% +uh a + b * a + b minus one over two. + + + align:start position:0% +uh a + b * a + b minus one over two. +That's my goal. And what I need to do is + + align:start position:0% +That's my goal. And what I need to do is + + + align:start position:0% +That's my goal. And what I need to do is +fill in the in between. + + align:start position:0% +fill in the in between. + + + align:start position:0% +fill in the in between. +Uh + + align:start position:0% +Uh + + + align:start position:0% +Uh +but this is not too hard because let's + + align:start position:0% +but this is not too hard because let's + + + align:start position:0% +but this is not too hard because let's +see. Uh I see a time b here and a * b + + align:start position:0% +see. Uh I see a time b here and a * b + + + align:start position:0% +see. Uh I see a time b here and a * b +here. I mean in fact you can just expand + + align:start position:0% +here. I mean in fact you can just expand + + + align:start position:0% +here. I mean in fact you can just expand +this out and you'll get exactly the same + + align:start position:0% +this out and you'll get exactly the same + + + align:start position:0% +this out and you'll get exactly the same +thing here. uh I think slightly more + + align:start position:0% +thing here. uh I think slightly more + + + align:start position:0% +thing here. uh I think slightly more +intuitive is to see oh look at this term + + align:start position:0% +intuitive is to see oh look at this term + + + align:start position:0% +intuitive is to see oh look at this term +this term and this term that is + + align:start position:0% +this term and this term that is + + + align:start position:0% +this term and this term that is +uh a^2 + 2 a b + b^ 2 that is a + b^ 2 + + align:start position:0% +uh a^2 + 2 a b + b^ 2 that is a + b^ 2 + + + align:start position:0% +uh a^2 + 2 a b + b^ 2 that is a + b^ 2 +and then we have a minus a minus b over + + align:start position:0% +and then we have a minus a minus b over + + + align:start position:0% +and then we have a minus a minus b over +2 but interject a rule in between we + + align:start position:0% +2 but interject a rule in between we + + + align:start position:0% +2 but interject a rule in between we +have a + b^ 2 minus a + b over 2 + + align:start position:0% +have a + b^ 2 minus a + b over 2 + + + align:start position:0% +have a + b^ 2 minus a + b over 2 +uh and then these two are the same + + align:start position:0% +uh and then these two are the same + + + align:start position:0% +uh and then these two are the same +thing. I think that's pretty clear. So + + align:start position:0% +thing. I think that's pretty clear. So + + + align:start position:0% +thing. I think that's pretty clear. So +cool. We did some algebra and the we + + align:start position:0% +cool. We did some algebra and the we + + + align:start position:0% +cool. We did some algebra and the we +just computed what we get out of + + align:start position:0% +just computed what we get out of + + + align:start position:0% +just computed what we get out of +induction and then boom, we get the + + align:start position:0% +induction and then boom, we get the + + + align:start position:0% +induction and then boom, we get the +answer n * n minus one over two and it + + align:start position:0% +answer n * n minus one over two and it + + + align:start position:0% +answer n * n minus one over two and it +works. How did we know this is the right + + align:start position:0% +works. How did we know this is the right + + + align:start position:0% +works. How did we know this is the right +answer? I mean, we were just told that + + align:start position:0% +answer? I mean, we were just told that + + + align:start position:0% +answer? I mean, we were just told that +by the theorem. Uh probably you would + + align:start position:0% +by the theorem. Uh probably you would + + + align:start position:0% +by the theorem. Uh probably you would +try this for very small n and make a + + align:start position:0% +try this for very small n and make a + + + align:start position:0% +try this for very small n and make a +conjecture. Oh, it seems like it's n * n + + align:start position:0% +conjecture. Oh, it seems like it's n * n + + + align:start position:0% +conjecture. Oh, it seems like it's n * n +minus one over two. Let's try to prove + + align:start position:0% +minus one over two. Let's try to prove + + + align:start position:0% +minus one over two. Let's try to prove +it. And when you assume the right thing, + + align:start position:0% +it. And when you assume the right thing, + + + align:start position:0% +it. And when you assume the right thing, +the proof just works. And it's kind of + + align:start position:0% +the proof just works. And it's kind of + + + align:start position:0% +the proof just works. And it's kind of +magical. And that's strong induction. + + align:start position:0% +magical. And that's strong induction. + + + align:start position:0% +magical. And that's strong induction. +Again, we needed strong induction here + + align:start position:0% +Again, we needed strong induction here + + + align:start position:0% +Again, we needed strong induction here +because we needed to assume uh what we + + align:start position:0% +because we needed to assume uh what we + + + align:start position:0% +because we needed to assume uh what we +wanted for all smaller n because we + + align:start position:0% +wanted for all smaller n because we + + + align:start position:0% +wanted for all smaller n because we +don't know what a and b are. This has to + + align:start position:0% +don't know what a and b are. This has to + + + align:start position:0% +don't know what a and b are. This has to +work for all a and b less than n. Um + + align:start position:0% +work for all a and b less than n. Um + + + align:start position:0% +work for all a and b less than n. Um +so luckily strong induction gives us + + align:start position:0% +so luckily strong induction gives us + + + align:start position:0% +so luckily strong induction gives us +that. + + align:start position:0% +that. + + + align:start position:0% +that. +All right, I have one more example to + + align:start position:0% +All right, I have one more example to + + + align:start position:0% +All right, I have one more example to +tell you about. Uh, + + align:start position:0% +tell you about. Uh, + + + align:start position:0% +tell you about. Uh, +a slightly more complicated version of + + align:start position:0% +a slightly more complicated version of + + + align:start position:0% +a slightly more complicated version of +the same thing. We're going to use + + align:start position:0% +the same thing. We're going to use + + + align:start position:0% +the same thing. We're going to use +strong induction. Don't need any of + + align:start position:0% +strong induction. Don't need any of + + + align:start position:0% +strong induction. Don't need any of +these. + + align:start position:0% + + + + align:start position:0% + +So, let's + + align:start position:0% +So, let's + + + align:start position:0% +So, let's +go. + + align:start position:0% + + + + align:start position:0% + +That's a problem called beat ordering. + + align:start position:0% + + + + align:start position:0% + +I guess somewhat relevant today because + + align:start position:0% +I guess somewhat relevant today because + + + align:start position:0% +I guess somewhat relevant today because +uh there's a Super Bowl, but this is + + align:start position:0% +uh there's a Super Bowl, but this is + + + align:start position:0% +uh there's a Super Bowl, but this is +just about + + align:start position:0% +just about + + + align:start position:0% +just about +any teams of games. Sorry, end teams in + + align:start position:0% +any teams of games. Sorry, end teams in + + + align:start position:0% +any teams of games. Sorry, end teams in +some game. And setup is that every two + + align:start position:0% +some game. And setup is that every two + + + align:start position:0% +some game. And setup is that every two +teams play a game + + align:start position:0% +teams play a game + + + align:start position:0% +teams play a game +and there are no ties. + + align:start position:0% + + + + align:start position:0% + +One team wins + + align:start position:0% +One team wins + + + align:start position:0% +One team wins +and the other loses. + + align:start position:0% +and the other loses. + + + align:start position:0% +and the other loses. +Okay, this is sort of like stranger + + align:start position:0% +Okay, this is sort of like stranger + + + align:start position:0% +Okay, this is sort of like stranger +friends and strangers uh where it's + + align:start position:0% +friends and strangers uh where it's + + + align:start position:0% +friends and strangers uh where it's +either one or the other. But in this + + align:start position:0% +either one or the other. But in this + + + align:start position:0% +either one or the other. But in this +case, it's asymmetric. It's not they're + + align:start position:0% +case, it's asymmetric. It's not they're + + + align:start position:0% +case, it's asymmetric. It's not they're +not both happy or both sad. One's happy + + align:start position:0% +not both happy or both sad. One's happy + + + align:start position:0% +not both happy or both sad. One's happy +and one is sad. + + align:start position:0% +and one is sad. + + + align:start position:0% +and one is sad. +Okay, this is what's called a roundroin + + align:start position:0% +Okay, this is what's called a roundroin + + + align:start position:0% +Okay, this is what's called a roundroin +tournament. Most sports are not played + + align:start position:0% +tournament. Most sports are not played + + + align:start position:0% +tournament. Most sports are not played +this way unless it's small number of + + align:start position:0% +this way unless it's small number of + + + align:start position:0% +this way unless it's small number of +teams because it's a lot of different + + align:start position:0% +teams because it's a lot of different + + + align:start position:0% +teams because it's a lot of different +teams. It's actually n * n + one over + + align:start position:0% +teams. It's actually n * n + one over + + + align:start position:0% +teams. It's actually n * n + one over +two teams uh games which is a lot. All + + align:start position:0% +two teams uh games which is a lot. All + + + align:start position:0% +two teams uh games which is a lot. All +right. So what we would like + + align:start position:0% +right. So what we would like + + + align:start position:0% +right. So what we would like +is what's called a beat ordering. + + align:start position:0% +is what's called a beat ordering. + + + align:start position:0% +is what's called a beat ordering. +Uh this is + + align:start position:0% +Uh this is + + + align:start position:0% +Uh this is +um an ordering of the teams + + align:start position:0% +um an ordering of the teams + + + align:start position:0% +um an ordering of the teams +t1 t2 up to tn + + align:start position:0% +t1 t2 up to tn + + + align:start position:0% +t1 t2 up to tn +such that + + align:start position:0% + + + + align:start position:0% + +b1 beat + + align:start position:0% +b1 beat + + + align:start position:0% +b1 beat +uh sorry t1 t for teams t1 beats t2 t2 + + align:start position:0% +uh sorry t1 t for teams t1 beats t2 t2 + + + align:start position:0% +uh sorry t1 t for teams t1 beats t2 t2 +beat t3 and so on + + align:start position:0% +beat t3 and so on + + + align:start position:0% +beat t3 and so on +and a TN minus one beats TN. + + align:start position:0% +and a TN minus one beats TN. + + + align:start position:0% +and a TN minus one beats TN. +Okay, let's draw a little example. Uh + + align:start position:0% +Okay, let's draw a little example. Uh + + + align:start position:0% +Okay, let's draw a little example. Uh +there's team rock, + + align:start position:0% +there's team rock, + + + align:start position:0% +there's team rock, +team scissors, + + align:start position:0% +team scissors, + + + align:start position:0% +team scissors, +and team paper. + + align:start position:0% +and team paper. + + + align:start position:0% +and team paper. +Okay, paper beats rock, rock beats + + align:start position:0% +Okay, paper beats rock, rock beats + + + align:start position:0% +Okay, paper beats rock, rock beats +scissors, scissors beats paper. Okay, + + align:start position:0% +scissors, scissors beats paper. Okay, + + + align:start position:0% +scissors, scissors beats paper. Okay, +this is a possible outcome in a three + + align:start position:0% +this is a possible outcome in a three + + + align:start position:0% +this is a possible outcome in a three +team tournament. There's there's not + + align:start position:0% +team tournament. There's there's not + + + align:start position:0% +team tournament. There's there's not +necessarily one best team here. There is + + align:start position:0% +necessarily one best team here. There is + + + align:start position:0% +necessarily one best team here. There is +no best team. But maybe paper and rock + + align:start position:0% +no best team. But maybe paper and rock + + + align:start position:0% +no best team. But maybe paper and rock +play a game and it happens that paper + + align:start position:0% +play a game and it happens that paper + + + align:start position:0% +play a game and it happens that paper +won. Maybe rock plays against scissors + + align:start position:0% +won. Maybe rock plays against scissors + + + align:start position:0% +won. Maybe rock plays against scissors +and it happens rock one and scissors + + align:start position:0% +and it happens rock one and scissors + + + align:start position:0% +and it happens rock one and scissors +played against paper. It happens + + align:start position:0% +played against paper. It happens + + + align:start position:0% +played against paper. It happens +scissors one. Okay, you can tell why I + + align:start position:0% +scissors one. Okay, you can tell why I + + + align:start position:0% +scissors one. Okay, you can tell why I +named the teams this way. Uh then one + + align:start position:0% +named the teams this way. Uh then one + + + align:start position:0% +named the teams this way. Uh then one +way I could order these teams is paper, + + align:start position:0% +way I could order these teams is paper, + + + align:start position:0% +way I could order these teams is paper, +rock, + + align:start position:0% +rock, + + + align:start position:0% +rock, +scissors + + align:start position:0% +scissors + + + align:start position:0% +scissors +because paper beats rock, rock beats + + align:start position:0% +because paper beats rock, rock beats + + + align:start position:0% +because paper beats rock, rock beats +scissors. Okay, so this is sort of the + + align:start position:0% +scissors. Okay, so this is sort of the + + + align:start position:0% +scissors. Okay, so this is sort of the +input and this is my goal + + align:start position:0% +input and this is my goal + + + align:start position:0% +input and this is my goal +is to produce an ordering like this. But + + align:start position:0% +is to produce an ordering like this. But + + + align:start position:0% +is to produce an ordering like this. But +I need to do it for n teams not just for + + align:start position:0% +I need to do it for n teams not just for + + + align:start position:0% +I need to do it for n teams not just for +three. + + align:start position:0% +three. + + + align:start position:0% +three. +Okay. So let's uh do let's do strong + + align:start position:0% +Okay. So let's uh do let's do strong + + + align:start position:0% +Okay. So let's uh do let's do strong +induction + + align:start position:0% + + + + align:start position:0% + +to prove that uh the theorem is a bead + + align:start position:0% +to prove that uh the theorem is a bead + + + align:start position:0% +to prove that uh the theorem is a bead +ordering always exists. + + align:start position:0% + + + + align:start position:0% + +theorem. + + align:start position:0% + + + + align:start position:0% + +And when I say this always exists, what + + align:start position:0% +And when I say this always exists, what + + + align:start position:0% +And when I say this always exists, what +I really mean is uh for all n + + align:start position:0% +I really mean is uh for all n + + + align:start position:0% +I really mean is uh for all n +and then for all tournaments + + align:start position:0% +and then for all tournaments + + + align:start position:0% +and then for all tournaments +of size n + + align:start position:0% + + + + align:start position:0% + +uh there exists a beat order. + + align:start position:0% +uh there exists a beat order. + + + align:start position:0% +uh there exists a beat order. +Okay, there exists an ordering of the + + align:start position:0% +Okay, there exists an ordering of the + + + align:start position:0% +Okay, there exists an ordering of the +end team such the first one beat the + + align:start position:0% +end team such the first one beat the + + + align:start position:0% +end team such the first one beat the +second one, second one beat the third + + align:start position:0% +second one, second one beat the third + + + align:start position:0% +second one, second one beat the third +one and so on. I should say uh for all I + + align:start position:0% +one and so on. I should say uh for all I + + + align:start position:0% +one and so on. I should say uh for all I +uh t i beat t i + one. + + align:start position:0% +uh t i beat t i + one. + + + align:start position:0% +uh t i beat t i + one. +Okay, so we claim this is true. + + align:start position:0% +Okay, so we claim this is true. + + + align:start position:0% +Okay, so we claim this is true. +Proof by strong induction. + + align:start position:0% + + + + align:start position:0% + +So we're going to assume that this + + align:start position:0% +So we're going to assume that this + + + align:start position:0% +So we're going to assume that this +statement is true. namely this statement + + align:start position:0% +statement is true. namely this statement + + + align:start position:0% +statement is true. namely this statement +uh is true for smaller n and then we're + + align:start position:0% +uh is true for smaller n and then we're + + + align:start position:0% +uh is true for smaller n and then we're +going to prove it for n. + + align:start position:0% + + + + align:start position:0% + +Okay. Uh let's + + align:start position:0% +Okay. Uh let's + + + align:start position:0% +Okay. Uh let's +pick a team + + align:start position:0% +pick a team + + + align:start position:0% +pick a team +any team + + align:start position:0% +any team + + + align:start position:0% +any team +call it t. + + align:start position:0% +call it t. + + + align:start position:0% +call it t. +Then I'm going to split everything with + + align:start position:0% +Then I'm going to split everything with + + + align:start position:0% +Then I'm going to split everything with +respect to t. So I'm going to define uh + + align:start position:0% +respect to t. So I'm going to define uh + + + align:start position:0% +respect to t. So I'm going to define uh +W to be the set of teams that win + + align:start position:0% +W to be the set of teams that win + + + align:start position:0% +W to be the set of teams that win +against T. So this is going to be a set + + align:start position:0% +against T. So this is going to be a set + + + align:start position:0% +against T. So this is going to be a set +of all teams S where S beat T. + + align:start position:0% + + + + align:start position:0% + +So this is one versus T. These teams win + + align:start position:0% +So this is one versus T. These teams win + + + align:start position:0% +So this is one versus T. These teams win +versus T or one versus T. And L is going + + align:start position:0% +versus T or one versus T. And L is going + + + align:start position:0% +versus T or one versus T. And L is going +to be the set of teams that lose against + + align:start position:0% +to be the set of teams that lose against + + + align:start position:0% +to be the set of teams that lose against +T. So this is the set of teams S where + + align:start position:0% +T. So this is the set of teams S where + + + align:start position:0% +T. So this is the set of teams S where +TBS. + + align:start position:0% + + + + align:start position:0% + +So this is a loss versus T. Then + + align:start position:0% +So this is a loss versus T. Then + + + align:start position:0% +So this is a loss versus T. Then +intuitively what we'd like to do is put + + align:start position:0% +intuitively what we'd like to do is put + + + align:start position:0% +intuitively what we'd like to do is put +the winners first, then put T, then put + + align:start position:0% +the winners first, then put T, then put + + + align:start position:0% +the winners first, then put T, then put +the losers. + + align:start position:0% +the losers. + + + align:start position:0% +the losers. +I claim that works. Okay. But how do I + + align:start position:0% +I claim that works. Okay. But how do I + + + align:start position:0% +I claim that works. Okay. But how do I +order the winners? How do I order the + + align:start position:0% +order the winners? How do I order the + + + align:start position:0% +order the winners? How do I order the +losers? Well, by induction. + + align:start position:0% +losers? Well, by induction. + + + align:start position:0% +losers? Well, by induction. +I claim uh the size of w this vertical + + align:start position:0% +I claim uh the size of w this vertical + + + align:start position:0% +I claim uh the size of w this vertical +bar means the size of the set is less + + align:start position:0% +bar means the size of the set is less + + + align:start position:0% +bar means the size of the set is less +than n and the size of l is less than n + + align:start position:0% +than n and the size of l is less than n + + + align:start position:0% +than n and the size of l is less than n +because + + align:start position:0% +because + + + align:start position:0% +because +uh + + align:start position:0% +uh + + + align:start position:0% +uh +uh the size of the winners plus the size + + align:start position:0% +uh the size of the winners plus the size + + + align:start position:0% +uh the size of the winners plus the size +of the losers plus one equals n. This is + + align:start position:0% +of the losers plus one equals n. This is + + + align:start position:0% +of the losers plus one equals n. This is +a one. Why? because every team is either + + align:start position:0% +a one. Why? because every team is either + + + align:start position:0% +a one. Why? because every team is either +T or they won against T or they lost + + align:start position:0% +T or they won against T or they lost + + + align:start position:0% +T or they won against T or they lost +against T. So this is counting all of + + align:start position:0% +against T. So this is counting all of + + + align:start position:0% +against T. So this is counting all of +the teams. There's T itself, the ones + + align:start position:0% +the teams. There's T itself, the ones + + + align:start position:0% +the teams. There's T itself, the ones +that win against T, the ones that lose + + align:start position:0% +that win against T, the ones that lose + + + align:start position:0% +that win against T, the ones that lose +against T. Together that ex is exactly + + align:start position:0% +against T. Together that ex is exactly + + + align:start position:0% +against T. Together that ex is exactly +N. Every team is exactly one of these + + align:start position:0% +N. Every team is exactly one of these + + + align:start position:0% +N. Every team is exactly one of these +categories. Uh and there's a plus one + + align:start position:0% +categories. Uh and there's a plus one + + + align:start position:0% +categories. Uh and there's a plus one +here. + + align:start position:0% +here. + + + align:start position:0% +here. +And all of these are non- negative. + + align:start position:0% +And all of these are non- negative. + + + align:start position:0% +And all of these are non- negative. +These here W and L might be zero, but + + align:start position:0% +These here W and L might be zero, but + + + align:start position:0% +These here W and L might be zero, but +there's this plus one. That means both W + + align:start position:0% +there's this plus one. That means both W + + + align:start position:0% +there's this plus one. That means both W +and L are strictly less than M. So the + + align:start position:0% +and L are strictly less than M. So the + + + align:start position:0% +and L are strictly less than M. So the +induction applies to them. + + align:start position:0% +induction applies to them. + + + align:start position:0% +induction applies to them. +So by induction + + align:start position:0% +So by induction + + + align:start position:0% +So by induction +uh this thing is true for any tournament + + align:start position:0% +uh this thing is true for any tournament + + + align:start position:0% +uh this thing is true for any tournament +of size W there exists a beat ordering + + align:start position:0% +of size W there exists a beat ordering + + + align:start position:0% +of size W there exists a beat ordering +of W. For every tournament of size L + + align:start position:0% +of W. For every tournament of size L + + + align:start position:0% +of W. For every tournament of size L +there exists a beat uh ordering of L. So + + align:start position:0% +there exists a beat uh ordering of L. So + + + align:start position:0% +there exists a beat uh ordering of L. So +we get a beat ordering + + align:start position:0% +we get a beat ordering + + + align:start position:0% +we get a beat ordering +let's we get two of them really. Uh + + align:start position:0% +let's we get two of them really. Uh + + + align:start position:0% +let's we get two of them really. Uh +let's call it W1 + + align:start position:0% +let's call it W1 + + + align:start position:0% +let's call it W1 +W2 dot dot dot W size of W. This is for + + align:start position:0% +W2 dot dot dot W size of W. This is for + + + align:start position:0% +W2 dot dot dot W size of W. This is for +this is an ordering of capital W. And we + + align:start position:0% +this is an ordering of capital W. And we + + + align:start position:0% +this is an ordering of capital W. And we +get L1 L2 dot dot dot L size of L + + align:start position:0% +get L1 L2 dot dot dot L size of L + + + align:start position:0% +get L1 L2 dot dot dot L size of L +as a beat ordering of capital L + + align:start position:0% +as a beat ordering of capital L + + + align:start position:0% +as a beat ordering of capital L +and then + + align:start position:0% +and then + + + align:start position:0% +and then +uh we concatenate. + + align:start position:0% +uh we concatenate. + + + align:start position:0% +uh we concatenate. +So we claim uh + + align:start position:0% + + + + align:start position:0% + +W1 + + align:start position:0% +W1 + + + align:start position:0% +W1 +dot dot dot W size of W + + align:start position:0% +dot dot dot W size of W + + + align:start position:0% +dot dot dot W size of W +then T then L1 + + align:start position:0% +then T then L1 + + + align:start position:0% +then T then L1 +dot dot dot L size of L + + align:start position:0% +dot dot dot L size of L + + + align:start position:0% +dot dot dot L size of L +is a beat ordering + + align:start position:0% + + + + align:start position:0% + +of all N teams. + + align:start position:0% +of all N teams. + + + align:start position:0% +of all N teams. +Again, this is all the teams. All the + + align:start position:0% +Again, this is all the teams. All the + + + align:start position:0% +Again, this is all the teams. All the +teams either won against T or they are T + + align:start position:0% +teams either won against T or they are T + + + align:start position:0% +teams either won against T or they are T +or they lost against T. And the idea is + + align:start position:0% +or they lost against T. And the idea is + + + align:start position:0% +or they lost against T. And the idea is +this part is beat. W1 beats W2. W2 beats + + align:start position:0% +this part is beat. W1 beats W2. W2 beats + + + align:start position:0% +this part is beat. W1 beats W2. W2 beats +W3 and so on by induction because this + + align:start position:0% +W3 and so on by induction because this + + + align:start position:0% +W3 and so on by induction because this +is a beat ordering of capital W. Over + + align:start position:0% +is a beat ordering of capital W. Over + + + align:start position:0% +is a beat ordering of capital W. Over +here, this is a beat ordering of of + + align:start position:0% +here, this is a beat ordering of of + + + align:start position:0% +here, this is a beat ordering of of +capital L. And so by induction, uh all + + align:start position:0% +capital L. And so by induction, uh all + + + align:start position:0% +capital L. And so by induction, uh all +these are are okay. L1 beat L2, L2 beat + + align:start position:0% +these are are okay. L1 beat L2, L2 beat + + + align:start position:0% +these are are okay. L1 beat L2, L2 beat +so on, dot dot dot beat L size of L. The + + align:start position:0% +so on, dot dot dot beat L size of L. The + + + align:start position:0% +so on, dot dot dot beat L size of L. The +only things we need to check are these + + align:start position:0% +only things we need to check are these + + + align:start position:0% +only things we need to check are these +two commas. We need to check that W sub + + align:start position:0% +two commas. We need to check that W sub + + + align:start position:0% +two commas. We need to check that W sub +big W, W subsize of W beats T and T beat + + align:start position:0% +big W, W subsize of W beats T and T beat + + + align:start position:0% +big W, W subsize of W beats T and T beat +L1. Why are those true? By our + + align:start position:0% +L1. Why are those true? By our + + + align:start position:0% +L1. Why are those true? By our +definition of W and L. Everything in W + + align:start position:0% +definition of W and L. Everything in W + + + align:start position:0% +definition of W and L. Everything in W +beat T. So this is by by the definition + + align:start position:0% +beat T. So this is by by the definition + + + align:start position:0% +beat T. So this is by by the definition +of W. We know that all of these beat T. + + align:start position:0% +of W. We know that all of these beat T. + + + align:start position:0% +of W. We know that all of these beat T. +So in particular, this one beat T. And + + align:start position:0% +So in particular, this one beat T. And + + + align:start position:0% +So in particular, this one beat T. And +we know by the definition + + align:start position:0% +we know by the definition + + + align:start position:0% +we know by the definition +of L, + + align:start position:0% +of L, + + + align:start position:0% +of L, +uh, all of these teams lost against T. + + align:start position:0% +uh, all of these teams lost against T. + + + align:start position:0% +uh, all of these teams lost against T. +In other words, T beats all of these + + align:start position:0% +In other words, T beats all of these + + + align:start position:0% +In other words, T beats all of these +teams. In particular, T beat L1. And so + + align:start position:0% +teams. In particular, T beat L1. And so + + + align:start position:0% +teams. In particular, T beat L1. And so +by combining all these beat statements + + align:start position:0% +by combining all these beat statements + + + align:start position:0% +by combining all these beat statements +together, we know that this entire thing + + align:start position:0% +together, we know that this entire thing + + + align:start position:0% +together, we know that this entire thing +is a beat ordering. each item beats the + + align:start position:0% +is a beat ordering. each item beats the + + + align:start position:0% +is a beat ordering. each item beats the +one right after it. So it's a little + + align:start position:0% +one right after it. So it's a little + + + align:start position:0% +one right after it. So it's a little +more complicated, but again, we're just + + align:start position:0% +more complicated, but again, we're just + + + align:start position:0% +more complicated, but again, we're just +quite often with strong induction + + align:start position:0% +quite often with strong induction + + + align:start position:0% +quite often with strong induction +proofs, you apply induction twice. You + + align:start position:0% +proofs, you apply induction twice. You + + + align:start position:0% +proofs, you apply induction twice. You +you have some problem of size n, you + + align:start position:0% +you have some problem of size n, you + + + align:start position:0% +you have some problem of size n, you +split it into two parts. In general, you + + align:start position:0% +split it into two parts. In general, you + + + align:start position:0% +split it into two parts. In general, you +might split it into many parts. Then you + + align:start position:0% +might split it into many parts. Then you + + + align:start position:0% +might split it into many parts. Then you +recursively solve the two parts or the + + align:start position:0% +recursively solve the two parts or the + + + align:start position:0% +recursively solve the two parts or the +many parts. As long as they're strictly + + align:start position:0% +many parts. As long as they're strictly + + + align:start position:0% +many parts. As long as they're strictly +smaller than n. By induction, we know + + align:start position:0% +smaller than n. By induction, we know + + + align:start position:0% +smaller than n. By induction, we know +they work out. By strong induction, we + + align:start position:0% +they work out. By strong induction, we + + + align:start position:0% +they work out. By strong induction, we +know they work out. You take those + + align:start position:0% +know they work out. You take those + + + align:start position:0% +know they work out. You take those +solutions and you combine them in some + + align:start position:0% +solutions and you combine them in some + + + align:start position:0% +solutions and you combine them in some +way. Here we concatenated with t in the + + align:start position:0% +way. Here we concatenated with t in the + + + align:start position:0% +way. Here we concatenated with t in the +middle. Um over here we summed them up. + + align:start position:0% +middle. Um over here we summed them up. + + + align:start position:0% +middle. Um over here we summed them up. +We summed up the number of points we got + + align:start position:0% +We summed up the number of points we got + + + align:start position:0% +We summed up the number of points we got +in each one plus the number of points we + + align:start position:0% +in each one plus the number of points we + + + align:start position:0% +in each one plus the number of points we +got in the first step. Uh and in general + + align:start position:0% +got in the first step. Uh and in general + + + align:start position:0% +got in the first step. Uh and in general +you combine them in some way and you + + align:start position:0% +you combine them in some way and you + + + align:start position:0% +you combine them in some way and you +prove that it's still that you're uh the + + align:start position:0% +prove that it's still that you're uh the + + + align:start position:0% +prove that it's still that you're uh the +thing you want to prove holds for size n + + align:start position:0% +thing you want to prove holds for size n + + + align:start position:0% +thing you want to prove holds for size n +and then you get your theorem. So that + + align:start position:0% +and then you get your theorem. So that + + + align:start position:0% +and then you get your theorem. So that +is the power of strong induction. + + align:start position:0% +is the power of strong induction. + + + align:start position:0% +is the power of strong induction. +Thanks. \ No newline at end of file diff --git a/GbVdTqIvIPw.txt b/GbVdTqIvIPw.txt new file mode 100644 index 0000000000000000000000000000000000000000..47b752b84c71c02aa8c4320cd459b2e9c531a64e --- /dev/null +++ b/GbVdTqIvIPw.txt @@ -0,0 +1,6851 @@ +align:start position:0% + +great so where were we last time last + + align:start position:0% +great so where were we last time last + + + align:start position:0% +great so where were we last time last +time we had discovered that radiation + + align:start position:0% +time we had discovered that radiation + + + align:start position:0% +time we had discovered that radiation +and we're going back to lecture four + + align:start position:0% +and we're going back to lecture four + + + align:start position:0% +and we're going back to lecture four +notes because I think I have a little + + align:start position:0% +notes because I think I have a little + + + align:start position:0% +notes because I think I have a little +bit uh left on lecture four + + align:start position:0% +bit uh left on lecture four + + + align:start position:0% +bit uh left on lecture four +notes we discovered that radiation also + + align:start position:0% +notes we discovered that radiation also + + + align:start position:0% +notes we discovered that radiation also +behaves like a uh a + + align:start position:0% +behaves like a uh a + + + align:start position:0% +behaves like a uh a +particle and behaves like a particle as + + align:start position:0% +particle and behaves like a particle as + + + align:start position:0% +particle and behaves like a particle as +exhibited in this photoelectric effect + + align:start position:0% +exhibited in this photoelectric effect + + + align:start position:0% +exhibited in this photoelectric effect +that is in order to get an electron out + + align:start position:0% +that is in order to get an electron out + + + align:start position:0% +that is in order to get an electron out +what we needed to do was to put in a + + align:start position:0% +what we needed to do was to put in a + + + align:start position:0% +what we needed to do was to put in a +particle of energy we needed to put in a + + align:start position:0% +particle of energy we needed to put in a + + + align:start position:0% +particle of energy we needed to put in a +packet of energy we needed to put in a + + align:start position:0% +packet of energy we needed to put in a + + + align:start position:0% +packet of energy we needed to put in a +Quantum of + + align:start position:0% +Quantum of + + + align:start position:0% +Quantum of +energy and as long as that Quantum of + + align:start position:0% +energy and as long as that Quantum of + + + align:start position:0% +energy and as long as that Quantum of +energy that packet of energy that + + align:start position:0% +energy that packet of energy that + + + align:start position:0% +energy that packet of energy that +particle of energy was larger than the + + align:start position:0% +particle of energy was larger than the + + + align:start position:0% +particle of energy was larger than the +work function we would get one electron + + align:start position:0% +work function we would get one electron + + + align:start position:0% +work function we would get one electron +out for every packet we put in all + + align:start position:0% +out for every packet we put in all + + + align:start position:0% +out for every packet we put in all +right so that's an example of the + + align:start position:0% +right so that's an example of the + + + align:start position:0% +right so that's an example of the +particle like nature to radiation this + + align:start position:0% +particle like nature to radiation this + + + align:start position:0% +particle like nature to radiation this +photoelectric + + align:start position:0% +photoelectric + + + align:start position:0% +photoelectric +effect all right but um Einstein + + align:start position:0% +effect all right but um Einstein + + + align:start position:0% +effect all right but um Einstein +also went on to show an even more + + align:start position:0% +also went on to show an even more + + + align:start position:0% +also went on to show an even more +convincing property of the particle like + + align:start position:0% +convincing property of the particle like + + + align:start position:0% +convincing property of the particle like +nature of radiation or a + + align:start position:0% +nature of radiation or a + + + align:start position:0% +nature of radiation or a +photon and that is that he showed that a + + align:start position:0% +photon and that is that he showed that a + + + align:start position:0% +photon and that is that he showed that a +photon has + + align:start position:0% +photon has + + + align:start position:0% +photon has +momentum even though a photon does not + + align:start position:0% +momentum even though a photon does not + + + align:start position:0% +momentum even though a photon does not +have mass or essentially No Rest Mass + + align:start position:0% +have mass or essentially No Rest Mass + + + align:start position:0% +have mass or essentially No Rest Mass +okay and of course momentum is a very + + align:start position:0% +okay and of course momentum is a very + + + align:start position:0% +okay and of course momentum is a very +particle like property right momentum + + align:start position:0% +particle like property right momentum + + + align:start position:0% +particle like property right momentum +hey P for momentum is equal to the mass + + align:start position:0% +hey P for momentum is equal to the mass + + + align:start position:0% +hey P for momentum is equal to the mass +times velocity + + align:start position:0% +times velocity + + + align:start position:0% +times velocity +right so if a particle or if a if a + + align:start position:0% +right so if a particle or if a if a + + + align:start position:0% +right so if a particle or if a if a +photon if + + align:start position:0% +photon if + + + align:start position:0% +photon if +um if radiation has momentum well gee + + align:start position:0% +um if radiation has momentum well gee + + + align:start position:0% +um if radiation has momentum well gee +it's acting very much like a particle + + align:start position:0% +it's acting very much like a particle + + + align:start position:0% +it's acting very much like a particle +right all right how did he do this + + align:start position:0% +right all right how did he do this + + + align:start position:0% +right all right how did he do this +well Einstein took the relativistic + + align:start position:0% +well Einstein took the relativistic + + + align:start position:0% +well Einstein took the relativistic +equations of motion which he himself + + align:start position:0% +equations of motion which he himself + + + align:start position:0% +equations of motion which he himself +wrote + + align:start position:0% +wrote + + + align:start position:0% +wrote +down and what he showed from that is + + align:start position:0% +down and what he showed from that is + + + align:start position:0% +down and what he showed from that is +that a photon + + align:start position:0% +that a photon + + + align:start position:0% +that a photon +had momentum P + + align:start position:0% +had momentum P + + + align:start position:0% +had momentum P +here and the momentum of the photon was + + align:start position:0% +here and the momentum of the photon was + + + align:start position:0% +here and the momentum of the photon was +defined by the frequency of the + + align:start position:0% +defined by the frequency of the + + + align:start position:0% +defined by the frequency of the +radiation that is that momentum was + + align:start position:0% +radiation that is that momentum was + + + align:start position:0% +radiation that is that momentum was +given by H again Plank's constant there + + align:start position:0% +given by H again Plank's constant there + + + align:start position:0% +given by H again Plank's constant there +that quantization constant times the + + align:start position:0% +that quantization constant times the + + + align:start position:0% +that quantization constant times the +frequency over the speed of + + align:start position:0% +frequency over the speed of + + + align:start position:0% +frequency over the speed of +light and since of course we know the + + align:start position:0% +light and since of course we know the + + + align:start position:0% +light and since of course we know the +relationship between the frequency in + + align:start position:0% +relationship between the frequency in + + + align:start position:0% +relationship between the frequency in +the wavelength we can write the momentum + + align:start position:0% +the wavelength we can write the momentum + + + align:start position:0% +the wavelength we can write the momentum +of a photon as H over Lambda right so if + + align:start position:0% +of a photon as H over Lambda right so if + + + align:start position:0% +of a photon as H over Lambda right so if +you have radiation of some wavelength + + align:start position:0% +you have radiation of some wavelength + + + align:start position:0% +you have radiation of some wavelength +Lambda that + + align:start position:0% +Lambda that + + + align:start position:0% +Lambda that +radiation those photons have this + + align:start position:0% +radiation those photons have this + + + align:start position:0% +radiation those photons have this +momentum H over Lambda this Photon + + align:start position:0% +momentum H over Lambda this Photon + + + align:start position:0% +momentum H over Lambda this Photon +momentum even though photons don't have + + align:start position:0% +momentum even though photons don't have + + + align:start position:0% +momentum even though photons don't have +mass okay + + align:start position:0% +mass okay + + + align:start position:0% +mass okay +and the actual demonstration of this + + align:start position:0% +and the actual demonstration of this + + + align:start position:0% +and the actual demonstration of this +took a few more years experimentally + + align:start position:0% +took a few more years experimentally + + + align:start position:0% +took a few more years experimentally +took a few more years and it was + + align:start position:0% +took a few more years and it was + + + align:start position:0% +took a few more years and it was +demonstrated first in something called + + align:start position:0% +demonstrated first in something called + + + align:start position:0% +demonstrated first in something called +the Compton effect which was the + + align:start position:0% +the Compton effect which was the + + + align:start position:0% +the Compton effect which was the +interaction of an x-ray photon with some + + align:start position:0% +interaction of an x-ray photon with some + + + align:start position:0% +interaction of an x-ray photon with some +matter and you could see it transfer + + align:start position:0% +matter and you could see it transfer + + + align:start position:0% +matter and you could see it transfer +momentum and um I got to show you here a + + align:start position:0% +momentum and um I got to show you here a + + + align:start position:0% +momentum and um I got to show you here a +this uh website from the University of + + align:start position:0% +this uh website from the University of + + + align:start position:0% +this uh website from the University of +Colorado + + align:start position:0% +Colorado + + + align:start position:0% +Colorado +again and uh + + align:start position:0% +again and uh + + + align:start position:0% +again and uh +here this is a just a a uh a video of um + + align:start position:0% +here this is a just a a uh a video of um + + + align:start position:0% +here this is a just a a uh a video of um +you know a photon gun here shooting + + align:start position:0% +you know a photon gun here shooting + + + align:start position:0% +you know a photon gun here shooting +photons and here's this enemy atom + + align:start position:0% +photons and here's this enemy atom + + + align:start position:0% +photons and here's this enemy atom +coming at you and you're shooting these + + align:start position:0% +coming at you and you're shooting these + + + align:start position:0% +coming at you and you're shooting these +photons and sure enough you can uh repel + + align:start position:0% +photons and sure enough you can uh repel + + + align:start position:0% +photons and sure enough you can uh repel +that atom make it go the other direction + + align:start position:0% +that atom make it go the other direction + + + align:start position:0% +that atom make it go the other direction +because of the photon of the moment + + align:start position:0% +because of the photon of the moment + + + align:start position:0% +because of the photon of the moment +because of the momentum of the photon + + align:start position:0% +because of the momentum of the photon + + + align:start position:0% +because of the momentum of the photon +but of course if you lower the power and + + align:start position:0% +but of course if you lower the power and + + + align:start position:0% +but of course if you lower the power and +you're not really good with your fingers + + align:start position:0% +you're not really good with your fingers + + + align:start position:0% +you're not really good with your fingers +here you can get clobbered right right + + align:start position:0% +here you can get clobbered right right + + + align:start position:0% +here you can get clobbered right right +so so here now I'm going to try this + + align:start position:0% +so so here now I'm going to try this + + + align:start position:0% +so so here now I'm going to try this +again this is though almost too + + align:start position:0% +again this is though almost too + + + align:start position:0% +again this is though almost too +easy okay so now I lower the power so + + align:start position:0% +easy okay so now I lower the power so + + + align:start position:0% +easy okay so now I lower the power so +that the rate of the photons are coming + + align:start position:0% +that the rate of the photons are coming + + + align:start position:0% +that the rate of the photons are coming +are much slower and I'm going to be able + + align:start position:0% +are much slower and I'm going to be able + + + align:start position:0% +are much slower and I'm going to be able +to turn this guy around no problem there + + align:start position:0% +to turn this guy around no problem there + + + align:start position:0% +to turn this guy around no problem there +we go repel it right off okay so it it + + align:start position:0% +we go repel it right off okay so it it + + + align:start position:0% +we go repel it right off okay so it it +really is the case that uh let me see if + + align:start position:0% +really is the case that uh let me see if + + + align:start position:0% +really is the case that uh let me see if +I can get this guy + + align:start position:0% + + + + align:start position:0% + +here I got cled okay okay well you'll be + + align:start position:0% +here I got cled okay okay well you'll be + + + align:start position:0% +here I got cled okay okay well you'll be +better at that game than I + + align:start position:0% +better at that game than I + + + align:start position:0% +better at that game than I +[Laughter] + + align:start position:0% +[Laughter] + + + align:start position:0% +[Laughter] +am but um it was it it's just that + + align:start position:0% +am but um it was it it's just that + + + align:start position:0% +am but um it was it it's just that +phenomena what I'm showing you here that + + align:start position:0% +phenomena what I'm showing you here that + + + align:start position:0% +phenomena what I'm showing you here that +led to the experimental feat of Adam + + align:start position:0% +led to the experimental feat of Adam + + + align:start position:0% +led to the experimental feat of Adam +trapping you know trapping an atom in + + align:start position:0% +trapping you know trapping an atom in + + + align:start position:0% +trapping you know trapping an atom in +space and how did they do that well what + + align:start position:0% +space and how did they do that well what + + + align:start position:0% +space and how did they do that well what +they did is they took some unsuspecting + + align:start position:0% +they did is they took some unsuspecting + + + align:start position:0% +they did is they took some unsuspecting +adom and they came in with some photons + + align:start position:0% +adom and they came in with some photons + + + align:start position:0% +adom and they came in with some photons +laser beam high power laser beam + + align:start position:0% +laser beam high power laser beam + + + align:start position:0% +laser beam high power laser beam +directed in this way and of course that + + align:start position:0% +directed in this way and of course that + + + align:start position:0% +directed in this way and of course that +that push the atoms that push this atom + + align:start position:0% +that push the atoms that push this atom + + + align:start position:0% +that push the atoms that push this atom +down but now if you come in with a laser + + align:start position:0% +down but now if you come in with a laser + + + align:start position:0% +down but now if you come in with a laser +beam in that direction well the photon + + align:start position:0% +beam in that direction well the photon + + + align:start position:0% +beam in that direction well the photon +momentum is going to push the atom up so + + align:start position:0% +momentum is going to push the atom up so + + + align:start position:0% +momentum is going to push the atom up so +now you've constrained it in this + + align:start position:0% +now you've constrained it in this + + + align:start position:0% +now you've constrained it in this +Dimension and you do it you've send + + align:start position:0% +Dimension and you do it you've send + + + align:start position:0% +Dimension and you do it you've send +another laser beam this way and another + + align:start position:0% +another laser beam this way and another + + + align:start position:0% +another laser beam this way and another +one this way and now you've constrained + + align:start position:0% +one this way and now you've constrained + + + align:start position:0% +one this way and now you've constrained +it in this Dimension then you send a + + align:start position:0% +it in this Dimension then you send a + + + align:start position:0% +it in this Dimension then you send a +laser beam in this way and a laser beam + + align:start position:0% +laser beam in this way and a laser beam + + + align:start position:0% +laser beam in this way and a laser beam +in that way constrained it in the third + + align:start position:0% +in that way constrained it in the third + + + align:start position:0% +in that way constrained it in the third +dimension hey you've trapped an atom in + + align:start position:0% +dimension hey you've trapped an atom in + + + align:start position:0% +dimension hey you've trapped an atom in +space all right via Photon momentum and + + align:start position:0% +space all right via Photon momentum and + + + align:start position:0% +space all right via Photon momentum and +this is what Steve 2 and and Stanford + + align:start position:0% +this is what Steve 2 and and Stanford + + + align:start position:0% +this is what Steve 2 and and Stanford +and Bill Phillips at nist uh did uh in + + align:start position:0% +and Bill Phillips at nist uh did uh in + + + align:start position:0% +and Bill Phillips at nist uh did uh in +the middle 1990s and received a Nobel + + align:start position:0% +the middle 1990s and received a Nobel + + + align:start position:0% +the middle 1990s and received a Nobel +Prize for this Adam trapping here in uh + + align:start position:0% +Prize for this Adam trapping here in uh + + + align:start position:0% +Prize for this Adam trapping here in uh +in + + align:start position:0% +in + + + align:start position:0% +in +1977 no 1997 sorry okay Photon has + + align:start position:0% +1977 no 1997 sorry okay Photon has + + + align:start position:0% +1977 no 1997 sorry okay Photon has +momentum + + align:start position:0% +momentum + + + align:start position:0% +momentum +and the reason this is so important or + + align:start position:0% +and the reason this is so important or + + + align:start position:0% +and the reason this is so important or +the reason this experiment was also so + + align:start position:0% +the reason this experiment was also so + + + align:start position:0% +the reason this experiment was also so +important is because it is the first + + align:start position:0% +important is because it is the first + + + align:start position:0% +important is because it is the first +step in producing a Bose Einstein + + align:start position:0% +step in producing a Bose Einstein + + + align:start position:0% +step in producing a Bose Einstein +condensate a Bose Einstein + + align:start position:0% +condensate a Bose Einstein + + + align:start position:0% +condensate a Bose Einstein +condensate is um where you take an atom + + align:start position:0% +condensate is um where you take an atom + + + align:start position:0% +condensate is um where you take an atom +which has which is a bon actually and + + align:start position:0% +which has which is a bon actually and + + + align:start position:0% +which has which is a bon actually and +you cool it down to such low + + align:start position:0% +you cool it down to such low + + + align:start position:0% +you cool it down to such low +temperatures that they condense that + + align:start position:0% +temperatures that they condense that + + + align:start position:0% +temperatures that they condense that +these atoms condense so you've got to + + align:start position:0% +these atoms condense so you've got to + + + align:start position:0% +these atoms condense so you've got to +cool it down very much so you have to + + align:start position:0% +cool it down very much so you have to + + + align:start position:0% +cool it down very much so you have to +get to the micr Kelvin + + align:start position:0% +get to the micr Kelvin + + + align:start position:0% +get to the micr Kelvin +range and the first step in cooling an + + align:start position:0% +range and the first step in cooling an + + + align:start position:0% +range and the first step in cooling an +atom down is this atom trapping this + + align:start position:0% +atom down is this atom trapping this + + + align:start position:0% +atom down is this atom trapping this +laser atom trapping okay and this will + + align:start position:0% +laser atom trapping okay and this will + + + align:start position:0% +laser atom trapping okay and this will +get you down to Kelvin or a little bit + + align:start position:0% +get you down to Kelvin or a little bit + + + align:start position:0% +get you down to Kelvin or a little bit +lower or so and of course what I mean by + + align:start position:0% +lower or so and of course what I mean by + + + align:start position:0% +lower or so and of course what I mean by +lowering the temperature is that you + + align:start position:0% +lowering the temperature is that you + + + align:start position:0% +lowering the temperature is that you +know I load this atom down right the + + align:start position:0% +know I load this atom down right the + + + align:start position:0% +know I load this atom down right the +temperature of of the gas is related to + + align:start position:0% +temperature of of the gas is related to + + + align:start position:0% +temperature of of the gas is related to +how fast those atoms moving if I slow it + + align:start position:0% +how fast those atoms moving if I slow it + + + align:start position:0% +how fast those atoms moving if I slow it +down I'm cooling the gas right so this + + align:start position:0% +down I'm cooling the gas right so this + + + align:start position:0% +down I'm cooling the gas right so this +here is that first step in getting the + + align:start position:0% +here is that first step in getting the + + + align:start position:0% +here is that first step in getting the +atoms to condense it's the first step in + + align:start position:0% +atoms to condense it's the first step in + + + align:start position:0% +atoms to condense it's the first step in +cooling the gas down then there are many + + align:start position:0% +cooling the gas down then there are many + + + align:start position:0% +cooling the gas down then there are many +other + + align:start position:0% +other + + + align:start position:0% +other +steps and actually the Bine condensate + + align:start position:0% +steps and actually the Bine condensate + + + align:start position:0% +steps and actually the Bine condensate +one of the individuals who + + align:start position:0% +one of the individuals who + + + align:start position:0% +one of the individuals who +accomplish that feat is right here in + + align:start position:0% +accomplish that feat is right here in + + + align:start position:0% +accomplish that feat is right here in +the physics department one of my + + align:start position:0% +the physics department one of my + + + align:start position:0% +the physics department one of my +colleagues wolf Gan K kly many of you + + align:start position:0% +colleagues wolf Gan K kly many of you + + + align:start position:0% +colleagues wolf Gan K kly many of you +will get to meet Wolf Gang kly in fact + + align:start position:0% +will get to meet Wolf Gang kly in fact + + + align:start position:0% +will get to meet Wolf Gang kly in fact +he might even be teaching a section of + + align:start position:0% +he might even be teaching a section of + + + align:start position:0% +he might even be teaching a section of +801 is that right pardon recitation okay + + align:start position:0% +801 is that right pardon recitation okay + + + align:start position:0% +801 is that right pardon recitation okay +all right great maybe he'll tell you + + align:start position:0% +all right great maybe he'll tell you + + + align:start position:0% +all right great maybe he'll tell you +some more about it if he hasn't already + + align:start position:0% +some more about it if he hasn't already + + + align:start position:0% +some more about it if he hasn't already +okay all right so photons have + + align:start position:0% + + + + align:start position:0% + +momentum so now what have we seen + + align:start position:0% +momentum so now what have we seen + + + align:start position:0% +momentum so now what have we seen +well what we've seen is that radiation + + align:start position:0% +well what we've seen is that radiation + + + align:start position:0% +well what we've seen is that radiation +exhibits both the wav like behavior and + + align:start position:0% +exhibits both the wav like behavior and + + + align:start position:0% +exhibits both the wav like behavior and +this particle like behavior and just in + + align:start position:0% +this particle like behavior and just in + + + align:start position:0% +this particle like behavior and just in +general + + align:start position:0% +general + + + align:start position:0% +general +experiments where the radiation produces + + align:start position:0% +experiments where the radiation produces + + + align:start position:0% +experiments where the radiation produces +a change in matter like the + + align:start position:0% +a change in matter like the + + + align:start position:0% +a change in matter like the +photoelectric effect that's a change in + + align:start position:0% +photoelectric effect that's a change in + + + align:start position:0% +photoelectric effect that's a change in +matter right an electron gets ripped off + + align:start position:0% +matter right an electron gets ripped off + + + align:start position:0% +matter right an electron gets ripped off +of the + + align:start position:0% +of the + + + align:start position:0% +of the +material experiments in which a change + + align:start position:0% +material experiments in which a change + + + align:start position:0% +material experiments in which a change +in the matter uh is affected in that + + align:start position:0% +in the matter uh is affected in that + + + align:start position:0% +in the matter uh is affected in that +case usually the radiation exhibits + + align:start position:0% +case usually the radiation exhibits + + + align:start position:0% +case usually the radiation exhibits +particle like + + align:start position:0% +particle like + + + align:start position:0% +particle like +Behavior experiments in which the + + align:start position:0% +Behavior experiments in which the + + + align:start position:0% +Behavior experiments in which the +radiation interaction results in a + + align:start position:0% +radiation interaction results in a + + + align:start position:0% +radiation interaction results in a +change in the spatial distribution of + + align:start position:0% +change in the spatial distribution of + + + align:start position:0% +change in the spatial distribution of +the radiation well in that case then + + align:start position:0% +the radiation well in that case then + + + align:start position:0% +the radiation well in that case then +radiation exhibits its wavelike uh + + align:start position:0% +radiation exhibits its wavelike uh + + + align:start position:0% +radiation exhibits its wavelike uh +behavior and so you know it's not really + + align:start position:0% +behavior and so you know it's not really + + + align:start position:0% +behavior and so you know it's not really +a proper question or an appropriate + + align:start position:0% +a proper question or an appropriate + + + align:start position:0% +a proper question or an appropriate +question to ask whether light is a + + align:start position:0% +question to ask whether light is a + + + align:start position:0% +question to ask whether light is a +particle or is it a + + align:start position:0% +particle or is it a + + + align:start position:0% +particle or is it a +wave the appropriate question is is to + + align:start position:0% +wave the appropriate question is is to + + + align:start position:0% +wave the appropriate question is is to +ask whether light behaves like a + + align:start position:0% +ask whether light behaves like a + + + align:start position:0% +ask whether light behaves like a +particle or behaves like a wave + + align:start position:0% +particle or behaves like a wave + + + align:start position:0% +particle or behaves like a wave +depending on the particular experimental + + align:start position:0% +depending on the particular experimental + + + align:start position:0% +depending on the particular experimental +uh + + align:start position:0% +uh + + + align:start position:0% +uh +conditions now this kind of wave + + align:start position:0% +conditions now this kind of wave + + + align:start position:0% +conditions now this kind of wave +particle duality or the ability of it to + + align:start position:0% +particle duality or the ability of it to + + + align:start position:0% +particle duality or the ability of it to +behave like a wave or a particle is not + + align:start position:0% +behave like a wave or a particle is not + + + align:start position:0% +behave like a wave or a particle is not +a contradiction it's just the + + align:start position:0% +a contradiction it's just the + + + align:start position:0% +a contradiction it's just the +fundamental nature of light it might + + align:start position:0% +fundamental nature of light it might + + + align:start position:0% +fundamental nature of light it might +seem like a contradiction to you because + + align:start position:0% +seem like a contradiction to you because + + + align:start position:0% +seem like a contradiction to you because +your everyday + + align:start position:0% +your everyday + + + align:start position:0% +your everyday +experience doesn't allow you to see that + + align:start position:0% +experience doesn't allow you to see that + + + align:start position:0% +experience doesn't allow you to see that +both properties can be there your + + align:start position:0% +both properties can be there your + + + align:start position:0% +both properties can be there your +everyday experience says it's a particle + + align:start position:0% +everyday experience says it's a particle + + + align:start position:0% +everyday experience says it's a particle +or it's a wave right but this is a part + + align:start position:0% +or it's a wave right but this is a part + + + align:start position:0% +or it's a wave right but this is a part +of the of nature of our world that you + + align:start position:0% +of the of nature of our world that you + + + align:start position:0% +of the of nature of our world that you +don't have the experience with every + + align:start position:0% +don't have the experience with every + + + align:start position:0% +don't have the experience with every +single day so it seems strange strange + + align:start position:0% +single day so it seems strange strange + + + align:start position:0% +single day so it seems strange strange +but it is the way light works right it's + + align:start position:0% +but it is the way light works right it's + + + align:start position:0% +but it is the way light works right it's +like someone asked me what is the form + + align:start position:0% +like someone asked me what is the form + + + align:start position:0% +like someone asked me what is the form +of a photon and when you ask that + + align:start position:0% +of a photon and when you ask that + + + align:start position:0% +of a photon and when you ask that +question that's fine but you have to + + align:start position:0% +question that's fine but you have to + + + align:start position:0% +question that's fine but you have to +realize what you want for an answer is + + align:start position:0% +realize what you want for an answer is + + + align:start position:0% +realize what you want for an answer is +to draw an analogy between that Photon + + align:start position:0% +to draw an analogy between that Photon + + + align:start position:0% +to draw an analogy between that Photon +and something that you can experience + + align:start position:0% +and something that you can experience + + + align:start position:0% +and something that you can experience +every day and the bottom line is you + + align:start position:0% +every day and the bottom line is you + + + align:start position:0% +every day and the bottom line is you +can't draw that analogy correctly + + align:start position:0% +can't draw that analogy correctly + + + align:start position:0% +can't draw that analogy correctly +because that photon is not not something + + align:start position:0% +because that photon is not not something + + + align:start position:0% +because that photon is not not something +that you can relate correctly to your + + align:start position:0% +that you can relate correctly to your + + + align:start position:0% +that you can relate correctly to your +everyday experience it's a different + + align:start position:0% +everyday experience it's a different + + + align:start position:0% +everyday experience it's a different +part of nature it's just one that you + + align:start position:0% +part of nature it's just one that you + + + align:start position:0% +part of nature it's just one that you +don't see every day so it seems strange + + align:start position:0% +don't see every day so it seems strange + + + align:start position:0% +don't see every day so it seems strange +right so you have to be uh you have to + + align:start position:0% +right so you have to be uh you have to + + + align:start position:0% +right so you have to be uh you have to +be willing to accept kind of new rules + + align:start position:0% +be willing to accept kind of new rules + + + align:start position:0% +be willing to accept kind of new rules +new phenomena that are just outside of + + align:start position:0% +new phenomena that are just outside of + + + align:start position:0% +new phenomena that are just outside of +your everyday experience they're out + + align:start position:0% +your everyday experience they're out + + + align:start position:0% +your everyday experience they're out +there as you delve into nature more more + + align:start position:0% +there as you delve into nature more more + + + align:start position:0% +there as you delve into nature more more +deeply you'll see that + + align:start position:0% + + + + align:start position:0% + +Okay Okay so we've taken care of + + align:start position:0% +Okay Okay so we've taken care of + + + align:start position:0% +Okay Okay so we've taken care of +radiation the wave particle duality of + + align:start position:0% +radiation the wave particle duality of + + + align:start position:0% +radiation the wave particle duality of +light and matter and now what we've got + + align:start position:0% +light and matter and now what we've got + + + align:start position:0% +light and matter and now what we've got +to do is we got to talk about matter and + + align:start position:0% +to do is we got to talk about matter and + + + align:start position:0% +to do is we got to talk about matter and +we got to talk about its uh wav like + + align:start position:0% +we got to talk about its uh wav like + + + align:start position:0% +we got to talk about its uh wav like +properties + + align:start position:0% +properties + + + align:start position:0% +properties +and also its particle like + + align:start position:0% +and also its particle like + + + align:start position:0% +and also its particle like +properties well its particle like + + align:start position:0% +properties well its particle like + + + align:start position:0% +properties well its particle like +properties um are certainly something + + align:start position:0% +properties um are certainly something + + + align:start position:0% +properties um are certainly something +that is within your everyday experience + + align:start position:0% +that is within your everyday experience + + + align:start position:0% +that is within your everyday experience +right you can understand matter as a + + align:start position:0% +right you can understand matter as a + + + align:start position:0% +right you can understand matter as a +particle what's more difficult to + + align:start position:0% +particle what's more difficult to + + + align:start position:0% +particle what's more difficult to +understand is + + align:start position:0% +understand is + + + align:start position:0% +understand is +matter behaving like a + + align:start position:0% +matter behaving like a + + + align:start position:0% +matter behaving like a +wave so for + + align:start position:0% +wave so for + + + align:start position:0% +wave so for +example if you had uh the situation + + align:start position:0% +example if you had uh the situation + + + align:start position:0% +example if you had uh the situation +where you have a the surface of a nickel + + align:start position:0% +where you have a the surface of a nickel + + + align:start position:0% +where you have a the surface of a nickel +Crystal and what I'm showing you right + + align:start position:0% +Crystal and what I'm showing you right + + + align:start position:0% +Crystal and what I'm showing you right +up here are two nickel atoms just two + + align:start position:0% +up here are two nickel atoms just two + + + align:start position:0% +up here are two nickel atoms just two +nickel atoms of this surface + + align:start position:0% +nickel atoms of this surface + + + align:start position:0% +nickel atoms of this surface +here right and the two nickel atoms are + + align:start position:0% +here right and the two nickel atoms are + + + align:start position:0% +here right and the two nickel atoms are +spaced about 2 * 10us 10 m from each + + align:start position:0% +spaced about 2 * 10us 10 m from each + + + align:start position:0% +spaced about 2 * 10us 10 m from each +other given the lattice spacing of a + + align:start position:0% +other given the lattice spacing of a + + + align:start position:0% +other given the lattice spacing of a +nickel + + align:start position:0% +nickel + + + align:start position:0% +nickel +Crystal and now if I went and I sent + + align:start position:0% +Crystal and now if I went and I sent + + + align:start position:0% +Crystal and now if I went and I sent +electrons into this nickel surface and + + align:start position:0% +electrons into this nickel surface and + + + align:start position:0% +electrons into this nickel surface and +again I'm just showing you two of the + + align:start position:0% +again I'm just showing you two of the + + + align:start position:0% +again I'm just showing you two of the +atoms if I came in with electrons + + align:start position:0% +atoms if I came in with electrons + + + align:start position:0% +atoms if I came in with electrons +electrons are particles you know JJ + + align:start position:0% +electrons are particles you know JJ + + + align:start position:0% +electrons are particles you know JJ +Thompson showed us that and um uh + + align:start position:0% +Thompson showed us that and um uh + + + align:start position:0% +Thompson showed us that and um uh +eventually the mass of those electrons + + align:start position:0% +eventually the mass of those electrons + + + align:start position:0% +eventually the mass of those electrons +was determined but what you might expect + + align:start position:0% +was determined but what you might expect + + + align:start position:0% +was determined but what you might expect +is that those electrons would come in + + align:start position:0% +is that those electrons would come in + + + align:start position:0% +is that those electrons would come in +and then back scatter from these surface + + align:start position:0% +and then back scatter from these surface + + + align:start position:0% +and then back scatter from these surface +atoms and do so in all + + align:start position:0% +atoms and do so in all + + + align:start position:0% +atoms and do so in all +directions so that out here where we + + align:start position:0% +directions so that out here where we + + + align:start position:0% +directions so that out here where we +have a phosphor screen and now that + + align:start position:0% +have a phosphor screen and now that + + + align:start position:0% +have a phosphor screen and now that +screen happens to be curved just so + + align:start position:0% +screen happens to be curved just so + + + align:start position:0% +screen happens to be curved just so +it'll be easier for us to talk about the + + align:start position:0% +it'll be easier for us to talk about the + + + align:start position:0% +it'll be easier for us to talk about the +geometry of this problem here you would + + align:start position:0% +geometry of this problem here you would + + + align:start position:0% +geometry of this problem here you would +you might expect naively that the these + + align:start position:0% +you might expect naively that the these + + + align:start position:0% +you might expect naively that the these +electrons scatter in all Direction and + + align:start position:0% +electrons scatter in all Direction and + + + align:start position:0% +electrons scatter in all Direction and +everywhere where they hit the screen hey + + align:start position:0% +everywhere where they hit the screen hey + + + align:start position:0% +everywhere where they hit the screen hey +the screen lights up + + align:start position:0% +the screen lights up + + + align:start position:0% +the screen lights up +okay + + align:start position:0% +okay + + + align:start position:0% +okay +well this is just the experiment that + + align:start position:0% +well this is just the experiment that + + + align:start position:0% +well this is just the experiment that +Davidson and germer did in 1927 along + + align:start position:0% +Davidson and germer did in 1927 along + + + align:start position:0% +Davidson and germer did in 1927 along +with G Thompson George Thompson the son + + align:start position:0% +with G Thompson George Thompson the son + + + align:start position:0% +with G Thompson George Thompson the son +of JJ Thompson actually G Thompson did + + align:start position:0% +of JJ Thompson actually G Thompson did + + + align:start position:0% +of JJ Thompson actually G Thompson did +the experiment in a little different way + + align:start position:0% +the experiment in a little different way + + + align:start position:0% +the experiment in a little different way +than Davidson and gmer but I'm going to + + align:start position:0% +than Davidson and gmer but I'm going to + + + align:start position:0% +than Davidson and gmer but I'm going to +explain the DAV and germer experiment + + align:start position:0% +explain the DAV and germer experiment + + + align:start position:0% +explain the DAV and germer experiment +Here and Now what I've done is I've + + align:start position:0% +Here and Now what I've done is I've + + + align:start position:0% +Here and Now what I've done is I've +taken my nickel atoms and just made them + + align:start position:0% +taken my nickel atoms and just made them + + + align:start position:0% +taken my nickel atoms and just made them +smaller and I did so because I need to + + align:start position:0% +smaller and I did so because I need to + + + align:start position:0% +smaller and I did so because I need to +clean up this uh diagram a little bit + + align:start position:0% +clean up this uh diagram a little bit + + + align:start position:0% +clean up this uh diagram a little bit +for the geometry that we're going to do + + align:start position:0% +for the geometry that we're going to do + + + align:start position:0% +for the geometry that we're going to do +but I've left the lattice spacing + + align:start position:0% +but I've left the lattice spacing + + + align:start position:0% +but I've left the lattice spacing +accurate + + align:start position:0% +accurate + + + align:start position:0% +accurate +here and what Davidson and germer did is + + align:start position:0% +here and what Davidson and germer did is + + + align:start position:0% +here and what Davidson and germer did is +to bring in an electron Beam at 54 + + align:start position:0% +to bring in an electron Beam at 54 + + + align:start position:0% +to bring in an electron Beam at 54 +electron + + align:start position:0% +electron + + + align:start position:0% +electron +bolts and they look to see + + align:start position:0% +bolts and they look to see + + + align:start position:0% +bolts and they look to see +how these electrons scattered back from + + align:start position:0% +how these electrons scattered back from + + + align:start position:0% +how these electrons scattered back from +that surface right onto that screen and + + align:start position:0% +that surface right onto that screen and + + + align:start position:0% +that surface right onto that screen and +lo and behold what they found is that + + align:start position:0% +lo and behold what they found is that + + + align:start position:0% +lo and behold what they found is that +those electrons did not scatter + + align:start position:0% +those electrons did not scatter + + + align:start position:0% +those electrons did not scatter +isotropically they did not go in all + + align:start position:0% +isotropically they did not go in all + + + align:start position:0% +isotropically they did not go in all +directions but there seemed to be a + + align:start position:0% +directions but there seemed to be a + + + align:start position:0% +directions but there seemed to be a +preferred scattering angle + + align:start position:0% +preferred scattering angle + + + align:start position:0% +preferred scattering angle +here and one of those scattering angles + + align:start position:0% +here and one of those scattering angles + + + align:start position:0% +here and one of those scattering angles +right here is um 50 7° so this angle + + align:start position:0% +right here is um 50 7° so this angle + + + align:start position:0% +right here is um 50 7° so this angle +right in here that's the angle from the + + align:start position:0% +right in here that's the angle from the + + + align:start position:0% +right in here that's the angle from the +surface normal to the direction in which + + align:start position:0% +surface normal to the direction in which + + + align:start position:0% +surface normal to the direction in which +this electron scatters right so they + + align:start position:0% +this electron scatters right so they + + + align:start position:0% +this electron scatters right so they +observed some scattered intensity lots + + align:start position:0% +observed some scattered intensity lots + + + align:start position:0% +observed some scattered intensity lots +of electron flux at this angle here + + align:start position:0% +of electron flux at this angle here + + + align:start position:0% +of electron flux at this angle here +about 50.7 + + align:start position:0% +about 50.7 + + + align:start position:0% +about 50.7 +degrees and they observed a lot of + + align:start position:0% +degrees and they observed a lot of + + + align:start position:0% +degrees and they observed a lot of +intensity right at the normal angle + + align:start position:0% +intensity right at the normal angle + + + align:start position:0% +intensity right at the normal angle +right here so the electron comes in and + + align:start position:0% +right here so the electron comes in and + + + align:start position:0% +right here so the electron comes in and +scatters right + + align:start position:0% +scatters right + + + align:start position:0% +scatters right +back and and depending on the uh + + align:start position:0% +back and and depending on the uh + + + align:start position:0% +back and and depending on the uh +experimental conditions they observe + + align:start position:0% +experimental conditions they observe + + + align:start position:0% +experimental conditions they observe +some intensity at a very large + + align:start position:0% +some intensity at a very large + + + align:start position:0% +some intensity at a very large +scattering angle here all right what + + align:start position:0% +scattering angle here all right what + + + align:start position:0% +scattering angle here all right what +does this look like hey it looks like + + align:start position:0% +does this look like hey it looks like + + + align:start position:0% +does this look like hey it looks like +interference phenomena right looks like + + align:start position:0% +interference phenomena right looks like + + + align:start position:0% +interference phenomena right looks like +the results of the two slit experiment + + align:start position:0% +the results of the two slit experiment + + + align:start position:0% +the results of the two slit experiment +that we did there's a very bright + + align:start position:0% +that we did there's a very bright + + + align:start position:0% +that we did there's a very bright +spot most very intense spot right in the + + align:start position:0% +spot most very intense spot right in the + + + align:start position:0% +spot most very intense spot right in the +center then there's a dark spot then + + align:start position:0% +center then there's a dark spot then + + + align:start position:0% +center then there's a dark spot then +there's a very intense spot then there's + + align:start position:0% +there's a very intense spot then there's + + + align:start position:0% +there's a very intense spot then there's +a dark spot then another intense spot + + align:start position:0% +a dark spot then another intense spot + + + align:start position:0% +a dark spot then another intense spot +hey looks like interference + + align:start position:0% + + + + align:start position:0% + +phenomena well let's see if we can + + align:start position:0% +phenomena well let's see if we can + + + align:start position:0% +phenomena well let's see if we can +understand that interference + + align:start position:0% +understand that interference + + + align:start position:0% +understand that interference +phenomena so here's that same diagram I + + align:start position:0% +phenomena so here's that same diagram I + + + align:start position:0% +phenomena so here's that same diagram I +just uh cleaned it up a little + + align:start position:0% + + + + align:start position:0% + +bit and um so what we're doing in the + + align:start position:0% +bit and um so what we're doing in the + + + align:start position:0% +bit and um so what we're doing in the +experiment is we're bringing in a + + align:start position:0% +experiment is we're bringing in a + + + align:start position:0% +experiment is we're bringing in a +continuous stream of electrons and + + align:start position:0% +continuous stream of electrons and + + + align:start position:0% +continuous stream of electrons and +here's my continuous stream of elect + + align:start position:0% +here's my continuous stream of elect + + + align:start position:0% +here's my continuous stream of elect +Rons and I'm only showing you two + + align:start position:0% +Rons and I'm only showing you two + + + align:start position:0% +Rons and I'm only showing you two +atoms but the same thing's happening on + + align:start position:0% +atoms but the same thing's happening on + + + align:start position:0% +atoms but the same thing's happening on +a lot of + + align:start position:0% +a lot of + + + align:start position:0% +a lot of +atoms all right so what it looks like is + + align:start position:0% +atoms all right so what it looks like is + + + align:start position:0% +atoms all right so what it looks like is +that these electrons are coming in and + + align:start position:0% +that these electrons are coming in and + + + align:start position:0% +that these electrons are coming in and +then each one of these atoms are kind of + + align:start position:0% +then each one of these atoms are kind of + + + align:start position:0% +then each one of these atoms are kind of +acting like a point + + align:start position:0% +acting like a point + + + align:start position:0% +acting like a point +source reflecting the electrons + + align:start position:0% +source reflecting the electrons + + + align:start position:0% +source reflecting the electrons +isotropically as a wave right that is + + align:start position:0% +isotropically as a wave right that is + + + align:start position:0% +isotropically as a wave right that is +that there's a wave that's emanating out + + align:start position:0% +that there's a wave that's emanating out + + + align:start position:0% +that there's a wave that's emanating out +from each one of these atoms all right + + align:start position:0% +from each one of these atoms all right + + + align:start position:0% +from each one of these atoms all right +and of course as time goes on that + + align:start position:0% +and of course as time goes on that + + + align:start position:0% +and of course as time goes on that +propagates out and then another + + align:start position:0% +propagates out and then another + + + align:start position:0% +propagates out and then another +wavefront another maximum emanates out + + align:start position:0% +wavefront another maximum emanates out + + + align:start position:0% +wavefront another maximum emanates out +and of course the distance between these + + align:start position:0% +and of course the distance between these + + + align:start position:0% +and of course the distance between these +two Maxima is the + + align:start position:0% +two Maxima is the + + + align:start position:0% +two Maxima is the +wavelength right because this is the + + align:start position:0% +wavelength right because this is the + + + align:start position:0% +wavelength right because this is the +maximum wavefront here's another one + + align:start position:0% +maximum wavefront here's another one + + + align:start position:0% +maximum wavefront here's another one +with time it can continues to emanate + + align:start position:0% +with time it can continues to emanate + + + align:start position:0% +with time it can continues to emanate +out with time it continues to emanate + + align:start position:0% +out with time it continues to emanate + + + align:start position:0% +out with time it continues to emanate +out as long as we are uh throwing + + align:start position:0% +out as long as we are uh throwing + + + align:start position:0% +out as long as we are uh throwing +electrons at that nickel Crystal and it + + align:start position:0% +electrons at that nickel Crystal and it + + + align:start position:0% +electrons at that nickel Crystal and it +continues to eminate out until it gets + + align:start position:0% +continues to eminate out until it gets + + + align:start position:0% +continues to eminate out until it gets +to the screen and then we see some + + align:start position:0% +to the screen and then we see some + + + align:start position:0% +to the screen and then we see some +bright dark bright dark bright spots + + align:start position:0% +bright dark bright dark bright spots + + + align:start position:0% +bright dark bright dark bright spots +okay hey looks just like the two slit + + align:start position:0% +okay hey looks just like the two slit + + + align:start position:0% +okay hey looks just like the two slit +experiment and now if we go to analyze + + align:start position:0% +experiment and now if we go to analyze + + + align:start position:0% +experiment and now if we go to analyze +this and again this is the same drawing + + align:start position:0% +this and again this is the same drawing + + + align:start position:0% +this and again this is the same drawing +I just cleaned it up a little a little + + align:start position:0% +I just cleaned it up a little a little + + + align:start position:0% +I just cleaned it up a little a little +bit if you look at this point right here + + align:start position:0% +bit if you look at this point right here + + + align:start position:0% +bit if you look at this point right here +what do you see well you see the maximum + + align:start position:0% +what do you see well you see the maximum + + + align:start position:0% +what do you see well you see the maximum +of a wave scattered from atom one at the + + align:start position:0% +of a wave scattered from atom one at the + + + align:start position:0% +of a wave scattered from atom one at the +same point in space as the maximum of + + align:start position:0% +same point in space as the maximum of + + + align:start position:0% +same point in space as the maximum of +the wave scattered from atom + + align:start position:0% +the wave scattered from atom + + + align:start position:0% +the wave scattered from atom +two hey constructive + + align:start position:0% +two hey constructive + + + align:start position:0% +two hey constructive +interference next Point here again two + + align:start position:0% +interference next Point here again two + + + align:start position:0% +interference next Point here again two +Maxima the same point in space + + align:start position:0% +Maxima the same point in space + + + align:start position:0% +Maxima the same point in space +constructive interference here two + + align:start position:0% +constructive interference here two + + + align:start position:0% +constructive interference here two +maximum same point in space constructive + + align:start position:0% +maximum same point in space constructive + + + align:start position:0% +maximum same point in space constructive +interference everywhere along that line + + align:start position:0% +interference everywhere along that line + + + align:start position:0% +interference everywhere along that line +we have constructive interference and so + + align:start position:0% +we have constructive interference and so + + + align:start position:0% +we have constructive interference and so +if you project out to the screen you're + + align:start position:0% +if you project out to the screen you're + + + align:start position:0% +if you project out to the screen you're +going to have a bright spot there you're + + align:start position:0% +going to have a bright spot there you're + + + align:start position:0% +going to have a bright spot there you're +going to have electrons being scattered + + align:start position:0% +going to have electrons being scattered + + + align:start position:0% +going to have electrons being scattered +right in that angle + + align:start position:0% +right in that angle + + + align:start position:0% +right in that angle +okay and now we know we talked about + + align:start position:0% +okay and now we know we talked about + + + align:start position:0% +okay and now we know we talked about +last time what the condition was from + + align:start position:0% +last time what the condition was from + + + align:start position:0% +last time what the condition was from +for constructive + + align:start position:0% +for constructive + + + align:start position:0% +for constructive +interference and the condition is that + + align:start position:0% +interference and the condition is that + + + align:start position:0% +interference and the condition is that +the difference in the distance travel by + + align:start position:0% +the difference in the distance travel by + + + align:start position:0% +the difference in the distance travel by +the two waves that are constructively + + align:start position:0% +the two waves that are constructively + + + align:start position:0% +the two waves that are constructively +interfering and now I use the letters d + + align:start position:0% +interfering and now I use the letters d + + + align:start position:0% +interfering and now I use the letters d +instead of R okay but the difference in + + align:start position:0% +instead of R okay but the difference in + + + align:start position:0% +instead of R okay but the difference in +the distance has to be equal to an + + align:start position:0% +the distance has to be equal to an + + + align:start position:0% +the distance has to be equal to an +integral multiple of the + + align:start position:0% +integral multiple of the + + + align:start position:0% +integral multiple of the +wavelength and if you analyzed this line + + align:start position:0% +wavelength and if you analyzed this line + + + align:start position:0% +wavelength and if you analyzed this line +here of constructive interference you'd + + align:start position:0% +here of constructive interference you'd + + + align:start position:0% +here of constructive interference you'd +find it was n equal one the difference + + align:start position:0% +find it was n equal one the difference + + + align:start position:0% +find it was n equal one the difference +in the distance traveled was one Lambda + + align:start position:0% +in the distance traveled was one Lambda + + + align:start position:0% +in the distance traveled was one Lambda +all + + align:start position:0% +all + + + align:start position:0% +all +right and over here you can see a a row + + align:start position:0% +right and over here you can see a a row + + + align:start position:0% +right and over here you can see a a row +of constructive + + align:start position:0% +of constructive + + + align:start position:0% +of constructive +interference and if you Analyze This + + align:start position:0% +interference and if you Analyze This + + + align:start position:0% +interference and if you Analyze This +constructive interference you would find + + align:start position:0% +constructive interference you would find + + + align:start position:0% +constructive interference you would find +the difference in the distance traveled + + align:start position:0% +the difference in the distance traveled + + + align:start position:0% +the difference in the distance traveled +was 2 Lambda this is our second order + + align:start position:0% +was 2 Lambda this is our second order + + + align:start position:0% +was 2 Lambda this is our second order +defraction spot or second or order + + align:start position:0% +defraction spot or second or order + + + align:start position:0% +defraction spot or second or order +interference feature and then of course + + align:start position:0% +interference feature and then of course + + + align:start position:0% +interference feature and then of course +we have the zero order interference + + align:start position:0% +we have the zero order interference + + + align:start position:0% +we have the zero order interference +feature hey these electrons are behaving + + align:start position:0% +feature hey these electrons are behaving + + + align:start position:0% +feature hey these electrons are behaving +like waves right it's constructive and + + align:start position:0% +like waves right it's constructive and + + + align:start position:0% +like waves right it's constructive and +destructive + + align:start position:0% +destructive + + + align:start position:0% +destructive +interference now what we're going to + + align:start position:0% +interference now what we're going to + + + align:start position:0% +interference now what we're going to +do is that we're going to analyze the + + align:start position:0% +do is that we're going to analyze the + + + align:start position:0% +do is that we're going to analyze the +geometry of this setup a little bit more + + align:start position:0% +geometry of this setup a little bit more + + + align:start position:0% +geometry of this setup a little bit more +we didn't do this for the two slit + + align:start position:0% +we didn't do this for the two slit + + + align:start position:0% +we didn't do this for the two slit +experiment with light we could have but + + align:start position:0% +experiment with light we could have but + + + align:start position:0% +experiment with light we could have but +we didn't we're going to do it here for + + align:start position:0% +we didn't we're going to do it here for + + + align:start position:0% +we didn't we're going to do it here for +the electron scattering it's really the + + align:start position:0% +the electron scattering it's really the + + + align:start position:0% +the electron scattering it's really the +same + + align:start position:0% +same + + + align:start position:0% +same +thing and um we're going to do it just + + align:start position:0% +thing and um we're going to do it just + + + align:start position:0% +thing and um we're going to do it just +like Davidson and germer did it because + + align:start position:0% +like Davidson and germer did it because + + + align:start position:0% +like Davidson and germer did it because +from this + + align:start position:0% +from this + + + align:start position:0% +from this +analysis in particular from knowing what + + align:start position:0% +analysis in particular from knowing what + + + align:start position:0% +analysis in particular from knowing what +the scattering angle is this is the + + align:start position:0% +the scattering angle is this is the + + + align:start position:0% +the scattering angle is this is the +quantity that Davidson and germer wanted + + align:start position:0% +quantity that Davidson and germer wanted + + + align:start position:0% +quantity that Davidson and germer wanted +to measure right or we're really + + align:start position:0% +to measure right or we're really + + + align:start position:0% +to measure right or we're really +interested in this scattering angle + + align:start position:0% +interested in this scattering angle + + + align:start position:0% +interested in this scattering angle +which turns out to be 50.7 degrees for + + align:start position:0% +which turns out to be 50.7 degrees for + + + align:start position:0% +which turns out to be 50.7 degrees for +this first order defraction + + align:start position:0% +this first order defraction + + + align:start position:0% +this first order defraction +beam we're going to use + + align:start position:0% +beam we're going to use + + + align:start position:0% +beam we're going to use +that knowledge to calculate the + + align:start position:0% +that knowledge to calculate the + + + align:start position:0% +that knowledge to calculate the +wavelength of the electrons that's what + + align:start position:0% +wavelength of the electrons that's what + + + align:start position:0% +wavelength of the electrons that's what +we're we're aiming for + + align:start position:0% +we're we're aiming for + + + align:start position:0% +we're we're aiming for +here and we're going to do that because + + align:start position:0% +here and we're going to do that because + + + align:start position:0% +here and we're going to do that because +of this known condition right for + + align:start position:0% +of this known condition right for + + + align:start position:0% +of this known condition right for +constructive interference that the + + align:start position:0% +constructive interference that the + + + align:start position:0% +constructive interference that the +difference in the distance traveled by + + align:start position:0% +difference in the distance traveled by + + + align:start position:0% +difference in the distance traveled by +the two waves that gives the + + align:start position:0% +the two waves that gives the + + + align:start position:0% +the two waves that gives the +constructive interference has to be an + + align:start position:0% +constructive interference has to be an + + + align:start position:0% +constructive interference has to be an +integral multiple of the + + align:start position:0% +integral multiple of the + + + align:start position:0% +integral multiple of the +wavelength all right that's where we're + + align:start position:0% +wavelength all right that's where we're + + + align:start position:0% +wavelength all right that's where we're +headed so now see this line from atom + + align:start position:0% +headed so now see this line from atom + + + align:start position:0% +headed so now see this line from atom +number two to the screen I called it D2 + + align:start position:0% +number two to the screen I called it D2 + + + align:start position:0% +number two to the screen I called it D2 +D2 is the length of that line it's the + + align:start position:0% +D2 is the length of that line it's the + + + align:start position:0% +D2 is the length of that line it's the +distance that the wave has traveled from + + align:start position:0% +distance that the wave has traveled from + + + align:start position:0% +distance that the wave has traveled from +atom two to the + + align:start position:0% +atom two to the + + + align:start position:0% +atom two to the +screen D1 is the distance that the wav + + align:start position:0% +screen D1 is the distance that the wav + + + align:start position:0% +screen D1 is the distance that the wav +scattered from atom one has traveled to + + align:start position:0% +scattered from atom one has traveled to + + + align:start position:0% +scattered from atom one has traveled to +the screen all + + align:start position:0% +the screen all + + + align:start position:0% +the screen all +right now I'm going to draw a + + align:start position:0% +right now I'm going to draw a + + + align:start position:0% +right now I'm going to draw a +perpendicular right here all right I'm + + align:start position:0% +perpendicular right here all right I'm + + + align:start position:0% +perpendicular right here all right I'm +going to draw a perpendicular from atom + + align:start position:0% +going to draw a perpendicular from atom + + + align:start position:0% +going to draw a perpendicular from atom +one to this line 2 here's the right + + align:start position:0% +one to this line 2 here's the right + + + align:start position:0% +one to this line 2 here's the right +angle that's really nice because look at + + align:start position:0% +angle that's really nice because look at + + + align:start position:0% +angle that's really nice because look at +what this leg of the triangle is then + + align:start position:0% +what this leg of the triangle is then + + + align:start position:0% +what this leg of the triangle is then +it's D2 minus D1 hey that's a quantity + + align:start position:0% +it's D2 minus D1 hey that's a quantity + + + align:start position:0% +it's D2 minus D1 hey that's a quantity +that's going to be interesting to us + + align:start position:0% +that's going to be interesting to us + + + align:start position:0% +that's going to be interesting to us +okay all right now what you have to do + + align:start position:0% +okay all right now what you have to do + + + align:start position:0% +okay all right now what you have to do +is you have to convince yourself that + + align:start position:0% +is you have to convince yourself that + + + align:start position:0% +is you have to convince yourself that +this angle right in here in this + + align:start position:0% +this angle right in here in this + + + align:start position:0% +this angle right in here in this +triangle is equal to this scattering + + align:start position:0% +triangle is equal to this scattering + + + align:start position:0% +triangle is equal to this scattering +angle Theta all right if you're good at + + align:start position:0% +angle Theta all right if you're good at + + + align:start position:0% +angle Theta all right if you're good at +geometry you can see that + + align:start position:0% +geometry you can see that + + + align:start position:0% +geometry you can see that +immediately or you might have to think + + align:start position:0% +immediately or you might have to think + + + align:start position:0% +immediately or you might have to think +about it a little bit but it is equal to + + align:start position:0% +about it a little bit but it is equal to + + + align:start position:0% +about it a little bit but it is equal to +that + + align:start position:0% +that + + + align:start position:0% +that +okay well that's good because now I got + + align:start position:0% +okay well that's good because now I got + + + align:start position:0% +okay well that's good because now I got +a triangle right here and I know the + + align:start position:0% +a triangle right here and I know the + + + align:start position:0% +a triangle right here and I know the +length of one side that's the distance + + align:start position:0% +length of one side that's the distance + + + align:start position:0% +length of one side that's the distance +the spacing between the two nickel atoms + + align:start position:0% +the spacing between the two nickel atoms + + + align:start position:0% +the spacing between the two nickel atoms +in the + + align:start position:0% +in the + + + align:start position:0% +in the +Crystal and um I know what Theta is + + align:start position:0% +Crystal and um I know what Theta is + + + align:start position:0% +Crystal and um I know what Theta is +because that's what Davidson and germer + + align:start position:0% +because that's what Davidson and germer + + + align:start position:0% +because that's what Davidson and germer +measure it's pretty good I can use that + + align:start position:0% +measure it's pretty good I can use that + + + align:start position:0% +measure it's pretty good I can use that +uh I can use this geometry to say that + + align:start position:0% +uh I can use this geometry to say that + + + align:start position:0% +uh I can use this geometry to say that +sin Theta is equal to the opposite the + + align:start position:0% +sin Theta is equal to the opposite the + + + align:start position:0% +sin Theta is equal to the opposite the +length of the opposite side D2 minus D1 + + align:start position:0% +length of the opposite side D2 minus D1 + + + align:start position:0% +length of the opposite side D2 minus D1 +over the hypotenuse + + align:start position:0% +over the hypotenuse + + + align:start position:0% +over the hypotenuse +a + + align:start position:0% +a + + + align:start position:0% +a +okay and now if this is the condition + + align:start position:0% +okay and now if this is the condition + + + align:start position:0% +okay and now if this is the condition +that has to obtain to have constructive + + align:start position:0% +that has to obtain to have constructive + + + align:start position:0% +that has to obtain to have constructive +interference and then this + + align:start position:0% +interference and then this + + + align:start position:0% +interference and then this +expression is comes from the geometry of + + align:start position:0% +expression is comes from the geometry of + + + align:start position:0% +expression is comes from the geometry of +the problem that I'm solving so this is + + align:start position:0% +the problem that I'm solving so this is + + + align:start position:0% +the problem that I'm solving so this is +the theory this is the geometry of the + + align:start position:0% +the theory this is the geometry of the + + + align:start position:0% +the theory this is the geometry of the +problem I'm solving well then n Lambda + + align:start position:0% +problem I'm solving well then n Lambda + + + align:start position:0% +problem I'm solving well then n Lambda +has to be equal to a sin + + align:start position:0% + + + + align:start position:0% + +Theta and therefore I can rearrange that + + align:start position:0% +Theta and therefore I can rearrange that + + + align:start position:0% +Theta and therefore I can rearrange that +to get Lambda Lambda is equal to a sin + + align:start position:0% +to get Lambda Lambda is equal to a sin + + + align:start position:0% +to get Lambda Lambda is equal to a sin +Theta / + + align:start position:0% +Theta / + + + align:start position:0% +Theta / +n and now I can use this information + + align:start position:0% +n and now I can use this information + + + align:start position:0% +n and now I can use this information +here to calculate what Lambda is all + + align:start position:0% +here to calculate what Lambda is all + + + align:start position:0% +here to calculate what Lambda is all +right I know that the scattering angle + + align:start position:0% +right I know that the scattering angle + + + align:start position:0% +right I know that the scattering angle +is 50.7 + + align:start position:0% +is 50.7 + + + align:start position:0% +is 50.7 +De I know what n is it's the first order + + align:start position:0% +De I know what n is it's the first order + + + align:start position:0% +De I know what n is it's the first order +defraction feature because it is the + + align:start position:0% +defraction feature because it is the + + + align:start position:0% +defraction feature because it is the +most intense spot that's closest to the + + align:start position:0% +most intense spot that's closest to the + + + align:start position:0% +most intense spot that's closest to the +zero order the zero order is always + + align:start position:0% +zero order the zero order is always + + + align:start position:0% +zero order the zero order is always +going to be normal to your sample normal + + align:start position:0% +going to be normal to your sample normal + + + align:start position:0% +going to be normal to your sample normal +to the crystal all right so therefore I + + align:start position:0% +to the crystal all right so therefore I + + + align:start position:0% +to the crystal all right so therefore I +can plug some numbers in there and I get + + align:start position:0% +can plug some numbers in there and I get + + + align:start position:0% +can plug some numbers in there and I get +for the wavelength 1.66 * 10us 10 + + align:start position:0% +for the wavelength 1.66 * 10us 10 + + + align:start position:0% +for the wavelength 1.66 * 10us 10 +m all right so this experiment says that + + align:start position:0% +m all right so this experiment says that + + + align:start position:0% +m all right so this experiment says that +if you have electrons that are 54 EV in + + align:start position:0% +if you have electrons that are 54 EV in + + + align:start position:0% +if you have electrons that are 54 EV in +energy the wavelength of those electrons + + align:start position:0% +energy the wavelength of those electrons + + + align:start position:0% +energy the wavelength of those electrons +is 1.66 * 10 - 10 + + align:start position:0% +is 1.66 * 10 - 10 + + + align:start position:0% +is 1.66 * 10 - 10 +m okay so Davidson germer and Thompson + + align:start position:0% +m okay so Davidson germer and Thompson + + + align:start position:0% +m okay so Davidson germer and Thompson +hey not only did they demonstrate the + + align:start position:0% +hey not only did they demonstrate the + + + align:start position:0% +hey not only did they demonstrate the +interference phenomena of + + align:start position:0% +interference phenomena of + + + align:start position:0% +interference phenomena of +particles right particles that had Mass + + align:start position:0% +particles right particles that had Mass + + + align:start position:0% +particles right particles that had Mass +but but they were able to calculate from + + align:start position:0% +but but they were able to calculate from + + + align:start position:0% +but but they were able to calculate from +that experiment the wavelength the + + align:start position:0% +that experiment the wavelength the + + + align:start position:0% +that experiment the wavelength the +corresponding + + align:start position:0% +corresponding + + + align:start position:0% +corresponding +wavelength all right but now I just want + + align:start position:0% +wavelength all right but now I just want + + + align:start position:0% +wavelength all right but now I just want +to take a moment as an + + align:start position:0% +to take a moment as an + + + align:start position:0% +to take a moment as an +aside to tell you that this geometry + + align:start position:0% +aside to tell you that this geometry + + + align:start position:0% +aside to tell you that this geometry +that I Illustrated right here is the + + align:start position:0% +that I Illustrated right here is the + + + align:start position:0% +that I Illustrated right here is the +identical + + align:start position:0% +identical + + + align:start position:0% +identical +geometry that uh is used in x-ray + + align:start position:0% +geometry that uh is used in x-ray + + + align:start position:0% +geometry that uh is used in x-ray +defraction x-ray defraction is the + + align:start position:0% +defraction x-ray defraction is the + + + align:start position:0% +defraction x-ray defraction is the +interference or the defraction of x-rays + + align:start position:0% +interference or the defraction of x-rays + + + align:start position:0% +interference or the defraction of x-rays +photon + + align:start position:0% +photon + + + align:start position:0% +photon +right this is electron + + align:start position:0% +right this is electron + + + align:start position:0% +right this is electron +defraction but the geometries are the + + align:start position:0% +defraction but the geometries are the + + + align:start position:0% +defraction but the geometries are the +same the concepts are the same but the + + align:start position:0% +same the concepts are the same but the + + + align:start position:0% +same the concepts are the same but the +reason I bring up x-ray defraction is + + align:start position:0% +reason I bring up x-ray defraction is + + + align:start position:0% +reason I bring up x-ray defraction is +because it's a very important technique + + align:start position:0% +because it's a very important technique + + + align:start position:0% +because it's a very important technique +for you in your future whether you're + + align:start position:0% +for you in your future whether you're + + + align:start position:0% +for you in your future whether you're +going to be looking at materials to get + + align:start position:0% +going to be looking at materials to get + + + align:start position:0% +going to be looking at materials to get +the structure + + align:start position:0% +the structure + + + align:start position:0% +the structure +materials or whether you're going to be + + align:start position:0% +materials or whether you're going to be + + + align:start position:0% +materials or whether you're going to be +doing some kind of biological chemistry + + align:start position:0% +doing some kind of biological chemistry + + + align:start position:0% +doing some kind of biological chemistry +because x-ray + + align:start position:0% +because x-ray + + + align:start position:0% +because x-ray +defraction is used to get structures + + align:start position:0% +defraction is used to get structures + + + align:start position:0% +defraction is used to get structures +Crystal structures particularly of + + align:start position:0% +Crystal structures particularly of + + + align:start position:0% +Crystal structures particularly of +proteins and the reason why you want to + + align:start position:0% +proteins and the reason why you want to + + + align:start position:0% +proteins and the reason why you want to +know the structure of a protein is + + align:start position:0% +know the structure of a protein is + + + align:start position:0% +know the structure of a protein is +because that structure does give you + + align:start position:0% +because that structure does give you + + + align:start position:0% +because that structure does give you +some hints as to what the function of + + align:start position:0% +some hints as to what the function of + + + align:start position:0% +some hints as to what the function of +the protein is + + align:start position:0% +the protein is + + + align:start position:0% +the protein is +right and actually Professor drenan + + align:start position:0% +right and actually Professor drenan + + + align:start position:0% +right and actually Professor drenan +who's going to lecture the second half + + align:start position:0% +who's going to lecture the second half + + + align:start position:0% +who's going to lecture the second half +of the course that's her specialty is + + align:start position:0% +of the course that's her specialty is + + + align:start position:0% +of the course that's her specialty is +x-ray defraction of uh Pro uh Crystal + + align:start position:0% +x-ray defraction of uh Pro uh Crystal + + + align:start position:0% +x-ray defraction of uh Pro uh Crystal +proteins okay and I'm sure she'll tell + + align:start position:0% +proteins okay and I'm sure she'll tell + + + align:start position:0% +proteins okay and I'm sure she'll tell +you much more about + + align:start position:0% +you much more about + + + align:start position:0% +you much more about +that all right but in xrate Def + + align:start position:0% +that all right but in xrate Def + + + align:start position:0% +that all right but in xrate Def +fraction what they do is they use those + + align:start position:0% +fraction what they do is they use those + + + align:start position:0% +fraction what they do is they use those +results not to get the + + align:start position:0% +results not to get the + + + align:start position:0% +results not to get the +wavelength but they use those results to + + align:start position:0% +wavelength but they use those results to + + + align:start position:0% +wavelength but they use those results to +get this distance here a the distance + + align:start position:0% +get this distance here a the distance + + + align:start position:0% +get this distance here a the distance +between the atoms that's what I mean by + + align:start position:0% +between the atoms that's what I mean by + + + align:start position:0% +between the atoms that's what I mean by +getting out the + + align:start position:0% +getting out the + + + align:start position:0% +getting out the +structure in x-ray defraction they + + align:start position:0% +structure in x-ray defraction they + + + align:start position:0% +structure in x-ray defraction they +coming in with an x-ray beam and they + + align:start position:0% +coming in with an x-ray beam and they + + + align:start position:0% +coming in with an x-ray beam and they +know what the wavelength is of their + + align:start position:0% +know what the wavelength is of their + + + align:start position:0% +know what the wavelength is of their +x-ray beam so they know what Lambda is + + align:start position:0% +x-ray beam so they know what Lambda is + + + align:start position:0% +x-ray beam so they know what Lambda is +and then they go and measure what Theta + + align:start position:0% +and then they go and measure what Theta + + + align:start position:0% +and then they go and measure what Theta +is the scattering angle okay and from + + align:start position:0% +is the scattering angle okay and from + + + align:start position:0% +is the scattering angle okay and from +those two quantities Lambda and Theta + + align:start position:0% +those two quantities Lambda and Theta + + + align:start position:0% +those two quantities Lambda and Theta +they figure out what a is the distance + + align:start position:0% +they figure out what a is the distance + + + align:start position:0% +they figure out what a is the distance +between the atoms and therefore work out + + align:start position:0% +between the atoms and therefore work out + + + align:start position:0% +between the atoms and therefore work out +the structure of the protein okay so + + align:start position:0% +the structure of the protein okay so + + + align:start position:0% +the structure of the protein okay so +that's how x-ray fraction is actually + + align:start position:0% +that's how x-ray fraction is actually + + + align:start position:0% +that's how x-ray fraction is actually +used all + + align:start position:0% +used all + + + align:start position:0% +used all +right well um now I'm going to need the + + align:start position:0% +right well um now I'm going to need the + + + align:start position:0% +right well um now I'm going to need the +I can I think I can turn these back + + align:start position:0% +I can I think I can turn these back + + + align:start position:0% +I can I think I can turn these back +on just get this up a little + + align:start position:0% + + + + align:start position:0% + +bit I'm not going to get the screen all + + align:start position:0% +bit I'm not going to get the screen all + + + align:start position:0% +bit I'm not going to get the screen all +the way up because I still want that + + align:start position:0% +the way up because I still want that + + + align:start position:0% +the way up because I still want that +number + + align:start position:0% +number + + + align:start position:0% +number +actually + + align:start position:0% + + + + align:start position:0% + +okay now + + align:start position:0% + + + + align:start position:0% + +so not only did Davidson and germer and + + align:start position:0% +so not only did Davidson and germer and + + + align:start position:0% +so not only did Davidson and germer and +Thompson demonstrate the interference + + align:start position:0% +Thompson demonstrate the interference + + + align:start position:0% +Thompson demonstrate the interference +phenomena but they also um got out of + + align:start position:0% +phenomena but they also um got out of + + + align:start position:0% +phenomena but they also um got out of +all of that they got a value for the um + + align:start position:0% +all of that they got a value for the um + + + align:start position:0% +all of that they got a value for the um +for the + + align:start position:0% +for the + + + align:start position:0% +for the +wavelength and that was very + + align:start position:0% +wavelength and that was very + + + align:start position:0% +wavelength and that was very +important and the reason why it was so + + align:start position:0% +important and the reason why it was so + + + align:start position:0% +important and the reason why it was so +important is because um a few years + + align:start position:0% +important is because um a few years + + + align:start position:0% +important is because um a few years +before + + align:start position:0% +before + + + align:start position:0% +before +1924 there was a prediction ition for + + align:start position:0% +1924 there was a prediction ition for + + + align:start position:0% +1924 there was a prediction ition for +what the wavelength of particles ought + + align:start position:0% +what the wavelength of particles ought + + + align:start position:0% +what the wavelength of particles ought +to + + align:start position:0% +to + + + align:start position:0% +to +be and that prediction was made by this + + align:start position:0% +be and that prediction was made by this + + + align:start position:0% +be and that prediction was made by this +gentleman de Bo de + + align:start position:0% +gentleman de Bo de + + + align:start position:0% +gentleman de Bo de +bryley de + + align:start position:0% +bryley de + + + align:start position:0% +bryley de +bryley in his PhD thesis no + + align:start position:0% +bryley in his PhD thesis no + + + align:start position:0% +bryley in his PhD thesis no +less he made a prediction for what the + + align:start position:0% +less he made a prediction for what the + + + align:start position:0% +less he made a prediction for what the +wavelength of particles ought to + + align:start position:0% +wavelength of particles ought to + + + align:start position:0% +wavelength of particles ought to +be what he did is he took the + + align:start position:0% +be what he did is he took the + + + align:start position:0% +be what he did is he took the +relativistic equations of motion of + + align:start position:0% +relativistic equations of motion of + + + align:start position:0% +relativistic equations of motion of +Einstein the same identical equations he + + align:start position:0% +Einstein the same identical equations he + + + align:start position:0% +Einstein the same identical equations he +knew of Einstein's work PhD thesis right + + align:start position:0% +knew of Einstein's work PhD thesis right + + + align:start position:0% +knew of Einstein's work PhD thesis right +and he + + align:start position:0% +and he + + + align:start position:0% +and he +realized that those relativistic + + align:start position:0% +realized that those relativistic + + + align:start position:0% +realized that those relativistic +equations of + + align:start position:0% +equations of + + + align:start position:0% +equations of +motion applied to matter as well as to + + align:start position:0% +motion applied to matter as well as to + + + align:start position:0% +motion applied to matter as well as to +photons to + + align:start position:0% +photons to + + + align:start position:0% +photons to +radiation and so he said that if you if + + align:start position:0% +radiation and so he said that if you if + + + align:start position:0% +radiation and so he said that if you if +you have of course then a + + align:start position:0% +you have of course then a + + + align:start position:0% +you have of course then a +photon which has a wavelength Lambda of + + align:start position:0% +photon which has a wavelength Lambda of + + + align:start position:0% +photon which has a wavelength Lambda of +course then that momentum of that photon + + align:start position:0% +course then that momentum of that photon + + + align:start position:0% +course then that momentum of that photon +is p but since those equations also + + align:start position:0% +is p but since those equations also + + + align:start position:0% +is p but since those equations also +applied to matter he then said well if + + align:start position:0% +applied to matter he then said well if + + + align:start position:0% +applied to matter he then said well if +you have a particle with momentum P hey + + align:start position:0% +you have a particle with momentum P hey + + + align:start position:0% +you have a particle with momentum P hey +that particle ought to have a wavelength + + align:start position:0% +that particle ought to have a wavelength + + + align:start position:0% +that particle ought to have a wavelength +Lambda he turned Einstein's relativistic + + align:start position:0% +Lambda he turned Einstein's relativistic + + + align:start position:0% +Lambda he turned Einstein's relativistic +equations relativistic equations of + + align:start position:0% +equations relativistic equations of + + + align:start position:0% +equations relativistic equations of +motion around right he said well you + + align:start position:0% +motion around right he said well you + + + align:start position:0% +motion around right he said well you +know if radiation has a wavelength + + align:start position:0% +know if radiation has a wavelength + + + align:start position:0% +know if radiation has a wavelength +Lambda it ought to have momentum P this + + align:start position:0% +Lambda it ought to have momentum P this + + + align:start position:0% +Lambda it ought to have momentum P this +is what Einstein said de bryley said + + align:start position:0% +is what Einstein said de bryley said + + + align:start position:0% +is what Einstein said de bryley said +well then matter with a momentum P + + align:start position:0% +well then matter with a momentum P + + + align:start position:0% +well then matter with a momentum P +better have a wavelength + + align:start position:0% + + + + align:start position:0% + +Lambda okay that's de bry's + + align:start position:0% +Lambda okay that's de bry's + + + align:start position:0% +Lambda okay that's de bry's +wavelength isn't that amazing I think + + align:start position:0% +wavelength isn't that amazing I think + + + align:start position:0% +wavelength isn't that amazing I think +that's amazing why didn't Einstein + + align:start position:0% +that's amazing why didn't Einstein + + + align:start position:0% +that's amazing why didn't Einstein +realize this or did Einstein realize + + align:start position:0% +realize this or did Einstein realize + + + align:start position:0% +realize this or did Einstein realize +that I don't + + align:start position:0% +that I don't + + + align:start position:0% +that I don't +know but now let's see about this + + align:start position:0% +know but now let's see about this + + + align:start position:0% +know but now let's see about this +prediction + + align:start position:0% + + + + align:start position:0% + +here what we know is that in the deyle + + align:start position:0% +here what we know is that in the deyle + + + align:start position:0% +here what we know is that in the deyle +experiment that we had electrons of 54 + + align:start position:0% +experiment that we had electrons of 54 + + + align:start position:0% +experiment that we had electrons of 54 +EV that means that's the kinetic energy + + align:start position:0% +EV that means that's the kinetic energy + + + align:start position:0% +EV that means that's the kinetic energy +that's 12 M * V ^ 2 + + align:start position:0% +that's 12 M * V ^ 2 + + + align:start position:0% +that's 12 M * V ^ 2 +you can write kinetic energy as p^2 over + + align:start position:0% +you can write kinetic energy as p^2 over + + + align:start position:0% +you can write kinetic energy as p^2 over +2m you can convince yourself of this and + + align:start position:0% +2m you can convince yourself of this and + + + align:start position:0% +2m you can convince yourself of this and +this is useful to know for these kinds + + align:start position:0% +this is useful to know for these kinds + + + align:start position:0% +this is useful to know for these kinds +of problems all right p^2 over 2 m is + + align:start position:0% +of problems all right p^2 over 2 m is + + + align:start position:0% +of problems all right p^2 over 2 m is +the kinetic + + align:start position:0% +the kinetic + + + align:start position:0% +the kinetic +energy and + + align:start position:0% +energy and + + + align:start position:0% +energy and +therefore if this is the energy you can + + align:start position:0% +therefore if this is the energy you can + + + align:start position:0% +therefore if this is the energy you can +calculate the momentum of those 54 EV + + align:start position:0% +calculate the momentum of those 54 EV + + + align:start position:0% +calculate the momentum of those 54 EV +electrons so the + + align:start position:0% +electrons so the + + + align:start position:0% +electrons so the +momentum is 4.0 * 10 the- 24 kg m/ + + align:start position:0% +momentum is 4.0 * 10 the- 24 kg m/ + + + align:start position:0% +momentum is 4.0 * 10 the- 24 kg m/ +second and now we can use de bry's + + align:start position:0% +second and now we can use de bry's + + + align:start position:0% +second and now we can use de bry's +wavelength here that expression that he + + align:start position:0% +wavelength here that expression that he + + + align:start position:0% +wavelength here that expression that he +had + + align:start position:0% +had + + + align:start position:0% +had +uh gotten out of Einstein's relativistic + + align:start position:0% +uh gotten out of Einstein's relativistic + + + align:start position:0% +uh gotten out of Einstein's relativistic +equations of motion to solve for Lambda + + align:start position:0% +equations of motion to solve for Lambda + + + align:start position:0% +equations of motion to solve for Lambda +so that's H 6.6 26 * 10- 20 34 Jew + + align:start position:0% +so that's H 6.6 26 * 10- 20 34 Jew + + + align:start position:0% +so that's H 6.6 26 * 10- 20 34 Jew +seconds over over the + + align:start position:0% + + + + align:start position:0% + +momentum and that gives us 17 * 10us 10 + + align:start position:0% +momentum and that gives us 17 * 10us 10 + + + align:start position:0% +momentum and that gives us 17 * 10us 10 +m hey same as the + + align:start position:0% +m hey same as the + + + align:start position:0% +m hey same as the +experiment it predicted exactly what the + + align:start position:0% +experiment it predicted exactly what the + + + align:start position:0% +experiment it predicted exactly what the +experimentalist measured for the + + align:start position:0% +experimentalist measured for the + + + align:start position:0% +experimentalist measured for the +wavelength of the electron all right + + align:start position:0% +wavelength of the electron all right + + + align:start position:0% +wavelength of the electron all right +this was a real coup here for de bryley + + align:start position:0% +this was a real coup here for de bryley + + + align:start position:0% +this was a real coup here for de bryley +and for + + align:start position:0% +and for + + + align:start position:0% +and for +science so + + align:start position:0% +science so + + + align:start position:0% +science so +what do we have we have Davidson and + + align:start position:0% +what do we have we have Davidson and + + + align:start position:0% +what do we have we have Davidson and +germer and George + + align:start position:0% + + + + align:start position:0% + +Thompson who have demonstrated and in + + align:start position:0% +Thompson who have demonstrated and in + + + align:start position:0% +Thompson who have demonstrated and in +particular George Thompson who has + + align:start position:0% +particular George Thompson who has + + + align:start position:0% +particular George Thompson who has +demonstrated that uh an + + align:start position:0% +demonstrated that uh an + + + align:start position:0% +demonstrated that uh an +electron has wavelike + + align:start position:0% +electron has wavelike + + + align:start position:0% +electron has wavelike +behavior in contrast here's George + + align:start position:0% +behavior in contrast here's George + + + align:start position:0% +behavior in contrast here's George +Thompson's father JJ Thompson who has + + align:start position:0% +Thompson's father JJ Thompson who has + + + align:start position:0% +Thompson's father JJ Thompson who has +demonstrated that an electron is a + + align:start position:0% +demonstrated that an electron is a + + + align:start position:0% +demonstrated that an electron is a +particle has mass right + + align:start position:0% +particle has mass right + + + align:start position:0% +particle has mass right +and both the Son and the father are + + align:start position:0% +and both the Son and the father are + + + align:start position:0% +and both the Son and the father are +correct how often does that happen right + + align:start position:0% +correct how often does that happen right + + + align:start position:0% +correct how often does that happen right +it's really amazing + + align:start position:0% + + + + align:start position:0% + +story + + align:start position:0% +story + + + align:start position:0% +story +okay all right so + + align:start position:0% + + + + align:start position:0% + +now now I'm going to have to put the + + align:start position:0% +now now I'm going to have to put the + + + align:start position:0% +now now I'm going to have to put the +lights off here I'm getting my lights + + align:start position:0% +lights off here I'm getting my lights + + + align:start position:0% +lights off here I'm getting my lights +confused all right so now now we're at + + align:start position:0% +confused all right so now now we're at + + + align:start position:0% +confused all right so now now we're at +the point where + + align:start position:0% +the point where + + + align:start position:0% +the point where +um we can begin to understand the + + align:start position:0% +um we can begin to understand the + + + align:start position:0% +um we can begin to understand the +structure of the atam + + align:start position:0% +structure of the atam + + + align:start position:0% +structure of the atam +right because it was this + + align:start position:0% +right because it was this + + + align:start position:0% +right because it was this +realization that an electron had wav + + align:start position:0% +realization that an electron had wav + + + align:start position:0% +realization that an electron had wav +likee properties it was that + + align:start position:0% +likee properties it was that + + + align:start position:0% +likee properties it was that +realization of those wave likee + + align:start position:0% +realization of those wave likee + + + align:start position:0% +realization of those wave likee +properties that led uh this gentleman + + align:start position:0% +properties that led uh this gentleman + + + align:start position:0% +properties that led uh this gentleman +right here right to uh realized that + + align:start position:0% +right here right to uh realized that + + + align:start position:0% +right here right to uh realized that +maybe he had to treat the electrons as a + + align:start position:0% +maybe he had to treat the electrons as a + + + align:start position:0% +maybe he had to treat the electrons as a +wave Mr + + align:start position:0% +wave Mr + + + align:start position:0% +wave Mr +Schrodinger it was that realization that + + align:start position:0% +Schrodinger it was that realization that + + + align:start position:0% +Schrodinger it was that realization that +led Mr Schrodinger to write down the + + align:start position:0% +led Mr Schrodinger to write down the + + + align:start position:0% +led Mr Schrodinger to write down the +Schrodinger equation the wave + + align:start position:0% +Schrodinger equation the wave + + + align:start position:0% +Schrodinger equation the wave +equation the wave the equation of motion + + align:start position:0% +equation the wave the equation of motion + + + align:start position:0% +equation the wave the equation of motion +for + + align:start position:0% +for + + + align:start position:0% +for +particles like an + + align:start position:0% +particles like an + + + align:start position:0% +particles like an +electron that um actually have a + + align:start position:0% +electron that um actually have a + + + align:start position:0% +electron that um actually have a +wavelength on the order of their + + align:start position:0% +wavelength on the order of their + + + align:start position:0% +wavelength on the order of their +environment okay and actually I just + + align:start position:0% +environment okay and actually I just + + + align:start position:0% +environment okay and actually I just +realize that I skipped something in your + + align:start position:0% +realize that I skipped something in your + + + align:start position:0% +realize that I skipped something in your +notes that I wanted to talk + + align:start position:0% +notes that I wanted to talk + + + align:start position:0% +notes that I wanted to talk +about and I apologize for + + align:start position:0% +about and I apologize for + + + align:start position:0% +about and I apologize for +that we're going to get to the wave + + align:start position:0% +that we're going to get to the wave + + + align:start position:0% +that we're going to get to the wave +equation in a + + align:start position:0% +equation in a + + + align:start position:0% +equation in a +moment it's very + + align:start position:0% +moment it's very + + + align:start position:0% +moment it's very +important but I did want to just uh talk + + align:start position:0% +important but I did want to just uh talk + + + align:start position:0% +important but I did want to just uh talk +about for a moment + + align:start position:0% +about for a moment + + + align:start position:0% +about for a moment +why + + align:start position:0% +why + + + align:start position:0% +why +uh if + + align:start position:0% +uh if + + + align:start position:0% +uh if +particles have waves or have wavelike + + align:start position:0% +particles have waves or have wavelike + + + align:start position:0% +particles have waves or have wavelike +phenomena then why hadn't uh why hadn't + + align:start position:0% +phenomena then why hadn't uh why hadn't + + + align:start position:0% +phenomena then why hadn't uh why hadn't +this wavelike phenomena been seen + + align:start position:0% +this wavelike phenomena been seen + + + align:start position:0% +this wavelike phenomena been seen +before so what this also should mean + + align:start position:0% +before so what this also should mean + + + align:start position:0% +before so what this also should mean +with de bryley is that you and I have a + + align:start position:0% +with de bryley is that you and I have a + + + align:start position:0% +with de bryley is that you and I have a +wavelength because we got momentum we + + align:start position:0% +wavelength because we got momentum we + + + align:start position:0% +wavelength because we got momentum we +got mass times velocity we also ought to + + align:start position:0% +got mass times velocity we also ought to + + + align:start position:0% +got mass times velocity we also ought to +have a a wave + + align:start position:0% +have a a wave + + + align:start position:0% +have a a wave +l so + + align:start position:0% +l so + + + align:start position:0% +l so +um pardon they take a while to to go up + + align:start position:0% +um pardon they take a while to to go up + + + align:start position:0% +um pardon they take a while to to go up +yeah all right so let's uh consider the + + align:start position:0% +yeah all right so let's uh consider the + + + align:start position:0% +yeah all right so let's uh consider the +problem with our wavelength + + align:start position:0% + + + + align:start position:0% + +here well let's talk about the + + align:start position:0% +here well let's talk about the + + + align:start position:0% +here well let's talk about the +wavelength of a + + align:start position:0% +wavelength of a + + + align:start position:0% +wavelength of a +baseball so we have a 5 O baseball right + + align:start position:0% +baseball so we have a 5 O baseball right + + + align:start position:0% +baseball so we have a 5 O baseball right +being pck Ed by Kurt chilling at 90 M an + + align:start position:0% +being pck Ed by Kurt chilling at 90 M an + + + align:start position:0% +being pck Ed by Kurt chilling at 90 M an +hour all + + align:start position:0% +hour all + + + align:start position:0% +hour all +right and it's being pitched at a very + + align:start position:0% +right and it's being pitched at a very + + + align:start position:0% +right and it's being pitched at a very +large nickel Crystal so let's think of + + align:start position:0% +large nickel Crystal so let's think of + + + align:start position:0% +large nickel Crystal so let's think of +an experiment of + + align:start position:0% +an experiment of + + + align:start position:0% +an experiment of +defraction of baseballs from a large + + align:start position:0% +defraction of baseballs from a large + + + align:start position:0% +defraction of baseballs from a large +Crystal just like the defraction of the + + align:start position:0% +Crystal just like the defraction of the + + + align:start position:0% +Crystal just like the defraction of the +electrons uh from that nickel Crystal + + align:start position:0% +electrons uh from that nickel Crystal + + + align:start position:0% +electrons uh from that nickel Crystal +well let's calculate the momentum of + + align:start position:0% +well let's calculate the momentum of + + + align:start position:0% +well let's calculate the momentum of +that baseball + + align:start position:0% +that baseball + + + align:start position:0% +that baseball +that momentum is M time + + align:start position:0% +that momentum is M time + + + align:start position:0% +that momentum is M time +V and 5 ounces 90 miles per hour get all + + align:start position:0% +V and 5 ounces 90 miles per hour get all + + + align:start position:0% +V and 5 ounces 90 miles per hour get all +your units right it's + + align:start position:0% +your units right it's + + + align:start position:0% +your units right it's +5.6 kilogram meter per second all + + align:start position:0% +5.6 kilogram meter per second all + + + align:start position:0% +5.6 kilogram meter per second all +right then we're going to use de bry's + + align:start position:0% +right then we're going to use de bry's + + + align:start position:0% +right then we're going to use de bry's +relationship right here to calculate + + align:start position:0% +relationship right here to calculate + + + align:start position:0% +relationship right here to calculate +what the wavelength is of that pitched + + align:start position:0% +what the wavelength is of that pitched + + + align:start position:0% +what the wavelength is of that pitched +baseball and when we do that H is equal + + align:start position:0% +baseball and when we do that H is equal + + + align:start position:0% +baseball and when we do that H is equal +uh Lambda is equal H over P if you put + + align:start position:0% +uh Lambda is equal H over P if you put + + + align:start position:0% +uh Lambda is equal H over P if you put +in this m or you put in this P put in h + + align:start position:0% +in this m or you put in this P put in h + + + align:start position:0% +in this m or you put in this P put in h +hey that comes out to be 1.2 * 10- 34 + + align:start position:0% +hey that comes out to be 1.2 * 10- 34 + + + align:start position:0% +hey that comes out to be 1.2 * 10- 34 +M okay pretty + + align:start position:0% +M okay pretty + + + align:start position:0% +M okay pretty +small all right + + align:start position:0% +small all right + + + align:start position:0% +small all right +but what do we know well we know the + + align:start position:0% +but what do we know well we know the + + + align:start position:0% +but what do we know well we know the +condition for constructive interference + + align:start position:0% +condition for constructive interference + + + align:start position:0% +condition for constructive interference +D2 minus D1 has to be equal to n * + + align:start position:0% +D2 minus D1 has to be equal to n * + + + align:start position:0% +D2 minus D1 has to be equal to n * +Lambda has to be equal to a + + align:start position:0% +Lambda has to be equal to a + + + align:start position:0% +Lambda has to be equal to a +sin + + align:start position:0% +sin + + + align:start position:0% +sin +Theta + + align:start position:0% +Theta + + + align:start position:0% +Theta +right so now let's + + align:start position:0% +right so now let's + + + align:start position:0% +right so now let's +calculate what the angle Theta ought to + + align:start position:0% +calculate what the angle Theta ought to + + + align:start position:0% +calculate what the angle Theta ought to +be for the first or first order + + align:start position:0% +be for the first or first order + + + align:start position:0% +be for the first or first order +defraction feature of baseballs from a + + align:start position:0% +defraction feature of baseballs from a + + + align:start position:0% +defraction feature of baseballs from a +nickel Crystal so you have Kurt chilling + + align:start position:0% +nickel Crystal so you have Kurt chilling + + + align:start position:0% +nickel Crystal so you have Kurt chilling +throwing these baseballs one or another + + align:start position:0% +throwing these baseballs one or another + + + align:start position:0% +throwing these baseballs one or another +right at this nickel Crystal and you're + + align:start position:0% +right at this nickel Crystal and you're + + + align:start position:0% +right at this nickel Crystal and you're +trying to see at what angle you're going + + align:start position:0% +trying to see at what angle you're going + + + align:start position:0% +trying to see at what angle you're going +to see that first order defraction + + align:start position:0% +to see that first order defraction + + + align:start position:0% +to see that first order defraction +feature well we can set this up so that + + align:start position:0% +feature well we can set this up so that + + + align:start position:0% +feature well we can set this up so that +s Theta here is going to be equal to n + + align:start position:0% +s Theta here is going to be equal to n + + + align:start position:0% +s Theta here is going to be equal to n +Lambda over a so n is 1 Lambda is 1.2 * + + align:start position:0% +Lambda over a so n is 1 Lambda is 1.2 * + + + align:start position:0% +Lambda over a so n is 1 Lambda is 1.2 * +10- 34 + + align:start position:0% +10- 34 + + + align:start position:0% +10- 34 +M and then a is 2.15 * 10us 10 m hey if + + align:start position:0% +M and then a is 2.15 * 10us 10 m hey if + + + align:start position:0% +M and then a is 2.15 * 10us 10 m hey if +you go and evaluate what Theta ought to + + align:start position:0% +you go and evaluate what Theta ought to + + + align:start position:0% +you go and evaluate what Theta ought to +be it's 3 * 10 the- + + align:start position:0% +be it's 3 * 10 the- + + + align:start position:0% +be it's 3 * 10 the- +23° all right so that means I have my + + align:start position:0% +23° all right so that means I have my + + + align:start position:0% +23° all right so that means I have my +nickel huge nickel Crystal here and + + align:start position:0% +nickel huge nickel Crystal here and + + + align:start position:0% +nickel huge nickel Crystal here and +here's the normal to the sample well + + align:start position:0% +here's the normal to the sample well + + + align:start position:0% +here's the normal to the sample well +then that first order defraction feature + + align:start position:0% +then that first order defraction feature + + + align:start position:0% +then that first order defraction feature +here is at about 10us + + align:start position:0% +here is at about 10us + + + align:start position:0% +here is at about 10us +23° from the normal are you going to be + + align:start position:0% +23° from the normal are you going to be + + + align:start position:0% +23° from the normal are you going to be +able to resolve + + align:start position:0% +able to resolve + + + align:start position:0% +able to resolve +that no right you're not going to be + + align:start position:0% +that no right you're not going to be + + + align:start position:0% +that no right you're not going to be +able to see the the normal noral + + align:start position:0% +able to see the the normal noral + + + align:start position:0% +able to see the the normal noral +reflection and then no base balls and + + align:start position:0% +reflection and then no base balls and + + + align:start position:0% +reflection and then no base balls and +then a very + + align:start position:0% +then a very + + + align:start position:0% +then a very +intense uh very intense beam of + + align:start position:0% +intense uh very intense beam of + + + align:start position:0% +intense uh very intense beam of +baseballs you're not going to be able to + + align:start position:0% +baseballs you're not going to be able to + + + align:start position:0% +baseballs you're not going to be able to +resolve 10 the minus 20 23 + + align:start position:0% +resolve 10 the minus 20 23 + + + align:start position:0% +resolve 10 the minus 20 23 +degrees so you say well okay uh if + + align:start position:0% +degrees so you say well okay uh if + + + align:start position:0% +degrees so you say well okay uh if +that's the + + align:start position:0% +that's the + + + align:start position:0% +that's the +problem then maybe I can help myself + + align:start position:0% +problem then maybe I can help myself + + + align:start position:0% +problem then maybe I can help myself +out by + + align:start position:0% +out by + + + align:start position:0% +out by +changing this a here right by changing + + align:start position:0% +changing this a here right by changing + + + align:start position:0% +changing this a here right by changing +the distance of my uh particles that are + + align:start position:0% +the distance of my uh particles that are + + + align:start position:0% +the distance of my uh particles that are +doing the diffracting my two nickel + + align:start position:0% +doing the diffracting my two nickel + + + align:start position:0% +doing the diffracting my two nickel +atoms hey let's change that distance + + align:start position:0% +atoms hey let's change that distance + + + align:start position:0% +atoms hey let's change that distance +let's find some other Crystal such that + + align:start position:0% +let's find some other Crystal such that + + + align:start position:0% +let's find some other Crystal such that +I change that distance to oh let's see + + align:start position:0% +I change that distance to oh let's see + + + align:start position:0% +I change that distance to oh let's see +how about uh 7 * 10- 33 M all + + align:start position:0% +how about uh 7 * 10- 33 M all + + + align:start position:0% +how about uh 7 * 10- 33 M all +right when I do that and I go and + + align:start position:0% +right when I do that and I go and + + + align:start position:0% +right when I do that and I go and +calculate what Theta ought to be that + + align:start position:0% +calculate what Theta ought to be that + + + align:start position:0% +calculate what Theta ought to be that +first defraction feature well that comes + + align:start position:0% +first defraction feature well that comes + + + align:start position:0% +first defraction feature well that comes +out to about one + + align:start position:0% +out to about one + + + align:start position:0% +out to about one +degree + + align:start position:0% +degree + + + align:start position:0% +degree +so if I were pitching baseballs at the + + align:start position:0% +so if I were pitching baseballs at the + + + align:start position:0% +so if I were pitching baseballs at the +normal + + align:start position:0% +normal + + + align:start position:0% +normal +angle and I was looking to see if I had + + align:start position:0% +angle and I was looking to see if I had + + + align:start position:0% +angle and I was looking to see if I had +a maximum of + + align:start position:0% +a maximum of + + + align:start position:0% +a maximum of +baseballs one degree from that normal + + align:start position:0% +baseballs one degree from that normal + + + align:start position:0% +baseballs one degree from that normal +angle one degree could I resolve that ah + + align:start position:0% +angle one degree could I resolve that ah + + + align:start position:0% +angle one degree could I resolve that ah +maybe maybe you could get an experiment + + align:start position:0% +maybe maybe you could get an experiment + + + align:start position:0% +maybe maybe you could get an experiment +like that since it up maybe but the + + align:start position:0% +like that since it up maybe but the + + + align:start position:0% +like that since it up maybe but the +problem is Right + + align:start position:0% +problem is Right + + + align:start position:0% +problem is Right +Here Right the problem is in this a the + + align:start position:0% +Here Right the problem is in this a the + + + align:start position:0% +Here Right the problem is in this a the +distance between the atoms that are um + + align:start position:0% +distance between the atoms that are um + + + align:start position:0% +distance between the atoms that are um +the distance between the atoms and the + + align:start position:0% +the distance between the atoms and the + + + align:start position:0% +the distance between the atoms and the +nickel Crystal that are going to reflect + + align:start position:0% +nickel Crystal that are going to reflect + + + align:start position:0% +nickel Crystal that are going to reflect +these base balls this distance is 7 * + + align:start position:0% +these base balls this distance is 7 * + + + align:start position:0% +these base balls this distance is 7 * +10us 33 + + align:start position:0% +10us 33 + + + align:start position:0% +10us 33 +M how big was the diameter of a nucleus + + align:start position:0% + + + + align:start position:0% + +what + + align:start position:0% +what + + + align:start position:0% +what +-10 how about another + + align:start position:0% +-10 how about another + + + align:start position:0% +-10 how about another +number1 how about another + + align:start position:0% +number1 how about another + + + align:start position:0% +number1 how about another +number 14 10 Theus 14 MERS that's a good + + align:start position:0% +number 14 10 Theus 14 MERS that's a good + + + align:start position:0% +number 14 10 Theus 14 MERS that's a good +number to + + align:start position:0% +number to + + + align:start position:0% +number to +know what am I looking at here I'm + + align:start position:0% +know what am I looking at here I'm + + + align:start position:0% +know what am I looking at here I'm +looking at a distance between the atoms + + align:start position:0% +looking at a distance between the atoms + + + align:start position:0% +looking at a distance between the atoms +of 10us 33 MERS here hey we're 20 orders + + align:start position:0% +of 10us 33 MERS here hey we're 20 orders + + + align:start position:0% +of 10us 33 MERS here hey we're 20 orders +of magnitude smaller than the size of + + align:start position:0% +of magnitude smaller than the size of + + + align:start position:0% +of magnitude smaller than the size of +the nucleus do we have a crystal to + + align:start position:0% +the nucleus do we have a crystal to + + + align:start position:0% +the nucleus do we have a crystal to +defract baseballs off of where the atoms + + align:start position:0% +defract baseballs off of where the atoms + + + align:start position:0% +defract baseballs off of where the atoms +are 10us 33 meters + + align:start position:0% +are 10us 33 meters + + + align:start position:0% +are 10us 33 meters +apart + + align:start position:0% +apart + + + align:start position:0% +apart +uhuh okay we + + align:start position:0% +uhuh okay we + + + align:start position:0% +uhuh okay we +don't and that's why wav likee + + align:start position:0% +don't and that's why wav likee + + + align:start position:0% +don't and that's why wav likee +phenomena on macroscopic particles has + + align:start position:0% +phenomena on macroscopic particles has + + + align:start position:0% +phenomena on macroscopic particles has +not been + + align:start position:0% +not been + + + align:start position:0% +not been +observed because our wavelengths your + + align:start position:0% +observed because our wavelengths your + + + align:start position:0% +observed because our wavelengths your +wavelength my wavelength baseball + + align:start position:0% +wavelength my wavelength baseball + + + align:start position:0% +wavelength my wavelength baseball +wavelengths these wavelengths are way + + align:start position:0% +wavelengths these wavelengths are way + + + align:start position:0% +wavelengths these wavelengths are way +too small they're they're way too small + + align:start position:0% +too small they're they're way too small + + + align:start position:0% +too small they're they're way too small +because the mass is way too + + align:start position:0% +because the mass is way too + + + align:start position:0% +because the mass is way too +large and so there is no way in the + + align:start position:0% +large and so there is no way in the + + + align:start position:0% +large and so there is no way in the +macroscopic world that we're going to + + align:start position:0% +macroscopic world that we're going to + + + align:start position:0% +macroscopic world that we're going to +see any effects any wav likee behavior + + align:start position:0% +see any effects any wav likee behavior + + + align:start position:0% +see any effects any wav likee behavior +for macroscopic objects our wavelengths + + align:start position:0% +for macroscopic objects our wavelengths + + + align:start position:0% +for macroscopic objects our wavelengths +are too small we've no way to see that + + align:start position:0% +are too small we've no way to see that + + + align:start position:0% +are too small we've no way to see that +wav likee Behavior you're going to need + + align:start position:0% +wav likee Behavior you're going to need + + + align:start position:0% +wav likee Behavior you're going to need +slits or you're going to need + + align:start position:0% +slits or you're going to need + + + align:start position:0% +slits or you're going to need +atoms that are about 10 of the - 33 M + + align:start position:0% +atoms that are about 10 of the - 33 M + + + align:start position:0% +atoms that are about 10 of the - 33 M +from each other and that's just not + + align:start position:0% +from each other and that's just not + + + align:start position:0% +from each other and that's just not +practical okay so for macroscopic + + align:start position:0% +practical okay so for macroscopic + + + align:start position:0% +practical okay so for macroscopic +objects for you and me hey our + + align:start position:0% +objects for you and me hey our + + + align:start position:0% +objects for you and me hey our +wavelengths don't mean anything they are + + align:start position:0% +wavelengths don't mean anything they are + + + align:start position:0% +wavelengths don't mean anything they are +of no consequence in the observation of + + align:start position:0% +of no consequence in the observation of + + + align:start position:0% +of no consequence in the observation of +what we see around us right however they + + align:start position:0% +what we see around us right however they + + + align:start position:0% +what we see around us right however they +have lots of + + align:start position:0% +have lots of + + + align:start position:0% +have lots of +consequences for particles such as an + + align:start position:0% +consequences for particles such as an + + + align:start position:0% +consequences for particles such as an +electron + + align:start position:0% +electron + + + align:start position:0% +electron +whose environment is on the scale of the + + align:start position:0% +whose environment is on the scale of the + + + align:start position:0% +whose environment is on the scale of the +their wavelength so I'm saying here in + + align:start position:0% +their wavelength so I'm saying here in + + + align:start position:0% +their wavelength so I'm saying here in +this in this case for the electron where + + align:start position:0% +this in this case for the electron where + + + align:start position:0% +this in this case for the electron where +the wavelength is 10us 10 m hey that is + + align:start position:0% +the wavelength is 10us 10 m hey that is + + + align:start position:0% +the wavelength is 10us 10 m hey that is +a wavelength that's on the order of the + + align:start position:0% +a wavelength that's on the order of the + + + align:start position:0% +a wavelength that's on the order of the +size of the electron's environment in an + + align:start position:0% +size of the electron's environment in an + + + align:start position:0% +size of the electron's environment in an +atom that's 10 Theus 10 + + align:start position:0% +atom that's 10 Theus 10 + + + align:start position:0% +atom that's 10 Theus 10 +m in those cases when that wavelength is + + align:start position:0% +m in those cases when that wavelength is + + + align:start position:0% +m in those cases when that wavelength is +is about the size of the environment + + align:start position:0% +is about the size of the environment + + + align:start position:0% +is about the size of the environment +then the wavelike properties + + align:start position:0% +then the wavelike properties + + + align:start position:0% +then the wavelike properties +matter they matter you see the + + align:start position:0% +matter they matter you see the + + + align:start position:0% +matter they matter you see the +interference phenomena you see those + + align:start position:0% +interference phenomena you see those + + + align:start position:0% +interference phenomena you see those +effects of those wavelike + + align:start position:0% +effects of those wavelike + + + align:start position:0% +effects of those wavelike +properties and it is just that + + align:start position:0% +properties and it is just that + + + align:start position:0% +properties and it is just that +realization that led schinger here who's + + align:start position:0% +realization that led schinger here who's + + + align:start position:0% +realization that led schinger here who's +now washed out right to write down the + + align:start position:0% +now washed out right to write down the + + + align:start position:0% +now washed out right to write down the +wave equation of + + align:start position:0% +wave equation of + + + align:start position:0% +wave equation of +motion and that's an equation of motion + + align:start position:0% +motion and that's an equation of motion + + + align:start position:0% +motion and that's an equation of motion +for particles whose wavelength is on the + + align:start position:0% +for particles whose wavelength is on the + + + align:start position:0% +for particles whose wavelength is on the +order of the size of their environment + + align:start position:0% +order of the size of their environment + + + align:start position:0% +order of the size of their environment +and you have to use that equation of + + align:start position:0% +and you have to use that equation of + + + align:start position:0% +and you have to use that equation of +motion to understand how that electron + + align:start position:0% +motion to understand how that electron + + + align:start position:0% +motion to understand how that electron +so to speak moves you can't use f equal + + align:start position:0% +so to speak moves you can't use f equal + + + align:start position:0% +so to speak moves you can't use f equal +Ma and that's where we will pick up next + + align:start position:0% +Ma and that's where we will pick up next + + + align:start position:0% +Ma and that's where we will pick up next +Wednesday \ No newline at end of file diff --git a/GwOklYjwHDI.txt b/GwOklYjwHDI.txt new file mode 100644 index 0000000000000000000000000000000000000000..ebe4f825701dcd7ec2c795479efe0b24e4140844 --- /dev/null +++ b/GwOklYjwHDI.txt @@ -0,0 +1,347 @@ +align:start position:0% + +in this segment we go through a quick + + align:start position:0% +in this segment we go through a quick + + + align:start position:0% +in this segment we go through a quick +review of a few properties of the + + align:start position:0% +review of a few properties of the + + + align:start position:0% +review of a few properties of the +Bernoulli process that we already know + + align:start position:0% +Bernoulli process that we already know + + + align:start position:0% +Bernoulli process that we already know +we start by thinking about the number of + + align:start position:0% +we start by thinking about the number of + + + align:start position:0% +we start by thinking about the number of +successes or arrivals in the first n + + align:start position:0% +successes or arrivals in the first n + + + align:start position:0% +successes or arrivals in the first n +time slots this is the following + + align:start position:0% +time slots this is the following + + + align:start position:0% +time slots this is the following +quantity at each time we add a 0 or a 1 + + align:start position:0% +quantity at each time we add a 0 or a 1 + + + align:start position:0% +quantity at each time we add a 0 or a 1 +depending on whether we've had a success + + align:start position:0% +depending on whether we've had a success + + + align:start position:0% +depending on whether we've had a success +or not and by adding those numbers we + + align:start position:0% +or not and by adding those numbers we + + + align:start position:0% +or not and by adding those numbers we +get the total number of successes now we + + align:start position:0% +get the total number of successes now we + + + align:start position:0% +get the total number of successes now we +already know that the number of + + align:start position:0% +already know that the number of + + + align:start position:0% +already know that the number of +successes in n trials obeys a binomial + + align:start position:0% +successes in n trials obeys a binomial + + + align:start position:0% +successes in n trials obeys a binomial +distribution so the probability of + + align:start position:0% +distribution so the probability of + + + align:start position:0% +distribution so the probability of +having K successes is given by the + + align:start position:0% +having K successes is given by the + + + align:start position:0% +having K successes is given by the +binomial probabilities and this is a + + align:start position:0% +binomial probabilities and this is a + + + align:start position:0% +binomial probabilities and this is a +formula that holds for k equal to 0 up + + align:start position:0% +formula that holds for k equal to 0 up + + + align:start position:0% +formula that holds for k equal to 0 up +to n which are the possible numbers for + + align:start position:0% +to n which are the possible numbers for + + + align:start position:0% +to n which are the possible numbers for +the random variable s for this random + + align:start position:0% +the random variable s for this random + + + align:start position:0% +the random variable s for this random +variable we know the expected value it's + + align:start position:0% +variable we know the expected value it's + + + align:start position:0% +variable we know the expected value it's +n times P and we also know it's variance + + align:start position:0% +n times P and we also know it's variance + + + align:start position:0% +n times P and we also know it's variance +which is n times P times 1 minus P + + align:start position:0% +which is n times P times 1 minus P + + + align:start position:0% +which is n times P times 1 minus P +another random variable of interest is + + align:start position:0% +another random variable of interest is + + + align:start position:0% +another random variable of interest is +the time until the first success or + + align:start position:0% +the time until the first success or + + + align:start position:0% +the time until the first success or +arrival so this is defined to be the + + align:start position:0% +arrival so this is defined to be the + + + align:start position:0% +arrival so this is defined to be the +smallest I for which the random variable + + align:start position:0% +smallest I for which the random variable + + + align:start position:0% +smallest I for which the random variable +X I is equal to 1 we have done this + + align:start position:0% +X I is equal to 1 we have done this + + + align:start position:0% +X I is equal to 1 we have done this +calculation in the past the probability + + align:start position:0% +calculation in the past the probability + + + align:start position:0% +calculation in the past the probability +that the first success appears at time k + + align:start position:0% +that the first success appears at time k + + + align:start position:0% +that the first success appears at time k +is the same as the probability that the + + align:start position:0% +is the same as the probability that the + + + align:start position:0% +is the same as the probability that the +first K minus 1 trials resulted in zeros + + align:start position:0% +first K minus 1 trials resulted in zeros + + + align:start position:0% +first K minus 1 trials resulted in zeros +and then the case trial resulted in a 1 + + align:start position:0% +and then the case trial resulted in a 1 + + + align:start position:0% +and then the case trial resulted in a 1 +and so the probability of this is 1 + + align:start position:0% +and so the probability of this is 1 + + + align:start position:0% +and so the probability of this is 1 +minus P the probability of 0 and we have + + align:start position:0% +minus P the probability of 0 and we have + + + align:start position:0% +minus P the probability of 0 and we have +K minus 1 of them times P the + + align:start position:0% +K minus 1 of them times P the + + + align:start position:0% +K minus 1 of them times P the +probability that the next trial gives us + + align:start position:0% +probability that the next trial gives us + + + align:start position:0% +probability that the next trial gives us +a success and this formula is valid for + + align:start position:0% +a success and this formula is valid for + + + align:start position:0% +a success and this formula is valid for +K being 1 2 and so on which is the range + + align:start position:0% +K being 1 2 and so on which is the range + + + align:start position:0% +K being 1 2 and so on which is the range +of possible values of this random + + align:start position:0% +of possible values of this random + + + align:start position:0% +of possible values of this random +variable T 1 this is the familiar + + align:start position:0% +variable T 1 this is the familiar + + + align:start position:0% +variable T 1 this is the familiar +geometric distribution that we have + + align:start position:0% +geometric distribution that we have + + + align:start position:0% +geometric distribution that we have +dealt with in several locations and + + align:start position:0% +dealt with in several locations and + + + align:start position:0% +dealt with in several locations and +particularly we know the expected value + + align:start position:0% +particularly we know the expected value + + + align:start position:0% +particularly we know the expected value +and the variance of a geometric random + + align:start position:0% +and the variance of a geometric random + + + align:start position:0% +and the variance of a geometric random +variable \ No newline at end of file diff --git a/H0MFJwQH2fo.txt b/H0MFJwQH2fo.txt new file mode 100644 index 0000000000000000000000000000000000000000..54c99588f1a307d8ab690fe854796d28b32ef4d9 --- /dev/null +++ b/H0MFJwQH2fo.txt @@ -0,0 +1,6475 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license + + align:start position:0% +a Creative Commons license + + + align:start position:0% +a Creative Commons license +your support will help MIT + + align:start position:0% +your support will help MIT + + + align:start position:0% +your support will help MIT +OpenCourseWare continue to offer high + + align:start position:0% +OpenCourseWare continue to offer high + + + align:start position:0% +OpenCourseWare continue to offer high +quality educational resources for free + + align:start position:0% +quality educational resources for free + + + align:start position:0% +quality educational resources for free +to make a donation or view additional + + align:start position:0% +to make a donation or view additional + + + align:start position:0% +to make a donation or view additional +materials from hundreds of MIT courses + + align:start position:0% +materials from hundreds of MIT courses + + + align:start position:0% +materials from hundreds of MIT courses +visit MIT opencourseware at ocw.mit.edu + + align:start position:0% +visit MIT opencourseware at ocw.mit.edu + + + align:start position:0% +visit MIT opencourseware at ocw.mit.edu +some content in this audio lecture is + + align:start position:0% +some content in this audio lecture is + + + align:start position:0% +some content in this audio lecture is +not covered under our Creative Commons + + align:start position:0% +not covered under our Creative Commons + + + align:start position:0% +not covered under our Creative Commons +license please listen to the end credits + + align:start position:0% +license please listen to the end credits + + + align:start position:0% +license please listen to the end credits +for more information ok alright so + + align:start position:0% +for more information ok alright so + + + align:start position:0% +for more information ok alright so +today's reading was the MDA paper by + + align:start position:0% +today's reading was the MDA paper by + + + align:start position:0% +today's reading was the MDA paper by +Robin Hood ek Robins Abeka matt LeBlanc + + align:start position:0% +Robin Hood ek Robins Abeka matt LeBlanc + + + align:start position:0% +Robin Hood ek Robins Abeka matt LeBlanc +and it's pretty III hope you found it + + align:start position:0% +and it's pretty III hope you found it + + + align:start position:0% +and it's pretty III hope you found it +pretty light reading because it was + + align:start position:0% +pretty light reading because it was + + + align:start position:0% +pretty light reading because it was +intended to be pretty light and the + + align:start position:0% +intended to be pretty light and the + + + align:start position:0% +intended to be pretty light and the +whole point of it was that we will be + + align:start position:0% +whole point of it was that we will be + + + align:start position:0% +whole point of it was that we will be +getting through this pretty quickly + + align:start position:0% +getting through this pretty quickly + + + align:start position:0% +getting through this pretty quickly +today so then you have time to sit with + + align:start position:0% +today so then you have time to sit with + + + align:start position:0% +today so then you have time to sit with +your teams talk about your project work + + align:start position:0% +your teams talk about your project work + + + align:start position:0% +your teams talk about your project work +on it a little bit all the prototyping + + align:start position:0% +on it a little bit all the prototyping + + + align:start position:0% +on it a little bit all the prototyping +but materials in the front I'm going to + + align:start position:0% +but materials in the front I'm going to + + + align:start position:0% +but materials in the front I'm going to +people put in the table the boxes all on + + align:start position:0% +people put in the table the boxes all on + + + align:start position:0% +people put in the table the boxes all on +the tables are you more or less see done + + align:start position:0% +the tables are you more or less see done + + + align:start position:0% +the tables are you more or less see done +with your tees right now more or less ok + + align:start position:0% +with your tees right now more or less ok + + + align:start position:0% +with your tees right now more or less ok +every team represented let's see you are + + align:start position:0% +every team represented let's see you are + + + align:start position:0% +every team represented let's see you are +the building team you guys are done + + align:start position:0% +the building team you guys are done + + + align:start position:0% +the building team you guys are done +which the different building team right + + align:start position:0% +which the different building team right + + + align:start position:0% +which the different building team right +the LEGO building team ok team is that + + align:start position:0% +the LEGO building team ok team is that + + + align:start position:0% +the LEGO building team ok team is that +the what the hidden information team the + + align:start position:0% +the what the hidden information team the + + + align:start position:0% +the what the hidden information team the +thievery stealing stuff oh and the pack + + align:start position:0% +thievery stealing stuff oh and the pack + + + align:start position:0% +thievery stealing stuff oh and the pack +tonic ok all right so all right cool + + align:start position:0% +tonic ok all right so all right cool + + + align:start position:0% +tonic ok all right so all right cool +Piper here great well hopefully you're + + align:start position:0% +Piper here great well hopefully you're + + + align:start position:0% +Piper here great well hopefully you're +able to like make a little bit of + + align:start position:0% +able to like make a little bit of + + + align:start position:0% +able to like make a little bit of +progress on your teams all your projects + + align:start position:0% +progress on your teams all your projects + + + align:start position:0% +progress on your teams all your projects +so who managed to like play a little bit + + align:start position:0% +so who managed to like play a little bit + + + align:start position:0% +so who managed to like play a little bit +more of the games whether it was the + + align:start position:0% +more of the games whether it was the + + + align:start position:0% +more of the games whether it was the +prototype that you played on Wednesday + + align:start position:0% +prototype that you played on Wednesday + + + align:start position:0% +prototype that you played on Wednesday +or whether it was something else that + + align:start position:0% +or whether it was something else that + + + align:start position:0% +or whether it was something else that +you deposit along the way who made sure + + align:start position:0% +you deposit along the way who made sure + + + align:start position:0% +you deposit along the way who made sure +she gets get some play cut okay a few + + align:start position:0% +she gets get some play cut okay a few + + + align:start position:0% +she gets get some play cut okay a few +people who do you play it with + + align:start position:0% + + + + align:start position:0% + +we're back to the drawing board and redo + + align:start position:0% +we're back to the drawing board and redo + + + align:start position:0% +we're back to the drawing board and redo +you games okay welcome yourselves okay + + align:start position:0% +you games okay welcome yourselves okay + + + align:start position:0% +you games okay welcome yourselves okay +and would you play with okay dog door + + align:start position:0% +and would you play with okay dog door + + + align:start position:0% +and would you play with okay dog door +pay its basic here hey what else what + + align:start position:0% +pay its basic here hey what else what + + + align:start position:0% +pay its basic here hey what else what +else + + align:start position:0% +else + + + align:start position:0% +else +yep just with the jet team yeah okay + + align:start position:0% + + + + align:start position:0% + +what did you the video play iteration + + align:start position:0% +what did you the video play iteration + + + align:start position:0% +what did you the video play iteration +that you didn't develop yourself anyone + + align:start position:0% +that you didn't develop yourself anyone + + + align:start position:0% +that you didn't develop yourself anyone +it's like if you play with that your + + align:start position:0% +it's like if you play with that your + + + align:start position:0% +it's like if you play with that your +team obviously you know you you okay so + + align:start position:0% +team obviously you know you you okay so + + + align:start position:0% +team obviously you know you you okay so +so if you played a version that you + + align:start position:0% +so if you played a version that you + + + align:start position:0% +so if you played a version that you +hadn't about yourself or if you played + + align:start position:0% +hadn't about yourself or if you played + + + align:start position:0% +hadn't about yourself or if you played +it with other people who weren't + + align:start position:0% +it with other people who weren't + + + align:start position:0% +it with other people who weren't +developing the game with you how do you + + align:start position:0% +developing the game with you how do you + + + align:start position:0% +developing the game with you how do you +what was some of the things that you + + align:start position:0% +what was some of the things that you + + + align:start position:0% +what was some of the things that you +felt that you felt about the game or + + align:start position:0% +felt that you felt about the game or + + + align:start position:0% +felt that you felt about the game or +what what do people say about your game + + align:start position:0% +what what do people say about your game + + + align:start position:0% +what what do people say about your game +once the game was done but what what do + + align:start position:0% +once the game was done but what what do + + + align:start position:0% +once the game was done but what what do +people seem to like or not like about it + + align:start position:0% +people seem to like or not like about it + + + align:start position:0% +people seem to like or not like about it +what what's up of like they got things + + align:start position:0% +what what's up of like they got things + + + align:start position:0% +what what's up of like they got things +that it was saying it did it end okay + + align:start position:0% +that it was saying it did it end okay + + + align:start position:0% +that it was saying it did it end okay +alright what else do you think it could + + align:start position:0% +alright what else do you think it could + + + align:start position:0% +alright what else do you think it could +have been negative feedback it could it + + align:start position:0% +have been negative feedback it could it + + + align:start position:0% +have been negative feedback it could it +could have been wow this is terrible + + align:start position:0% +could have been wow this is terrible + + + align:start position:0% +could have been wow this is terrible +because black what was the bad or it + + align:start position:0% +because black what was the bad or it + + + align:start position:0% +because black what was the bad or it +could have been wow that was kind of + + align:start position:0% +could have been wow that was kind of + + + align:start position:0% +could have been wow that was kind of +cool because of black + + align:start position:0% + + + + align:start position:0% + +nothing don't we give you any feedback + + align:start position:0% +nothing don't we give you any feedback + + + align:start position:0% +nothing don't we give you any feedback +they just kind of sat there passively + + align:start position:0% +they just kind of sat there passively + + + align:start position:0% +they just kind of sat there passively +why are you making us play this okay + + align:start position:0% +why are you making us play this okay + + + align:start position:0% +why are you making us play this okay +well I also week that that was for segue + + align:start position:0% +well I also week that that was for segue + + + align:start position:0% +well I also week that that was for segue +into a little bit it will talk about + + align:start position:0% +into a little bit it will talk about + + + align:start position:0% +into a little bit it will talk about +aesthetics actually uh maybe what I'll + + align:start position:0% +aesthetics actually uh maybe what I'll + + + align:start position:0% +aesthetics actually uh maybe what I'll +do that is I could make you play a game + + align:start position:0% +do that is I could make you play a game + + + align:start position:0% +do that is I could make you play a game +a short game that the game that you were + + align:start position:0% +a short game that the game that you were + + + align:start position:0% +a short game that the game that you were +seeing who's played it before yeah Oh a + + align:start position:0% +seeing who's played it before yeah Oh a + + + align:start position:0% +seeing who's played it before yeah Oh a +cysts also known as defense of which is + + align:start position:0% +cysts also known as defense of which is + + + align:start position:0% +cysts also known as defense of which is +easily confused Dora but it's not gonna + + align:start position:0% +easily confused Dora but it's not gonna + + + align:start position:0% +easily confused Dora but it's not gonna +all right if somebody would like to + + align:start position:0% +all right if somebody would like to + + + align:start position:0% +all right if somebody would like to +volunteer to play through early easy + + align:start position:0% +volunteer to play through early easy + + + align:start position:0% +volunteer to play through early easy +level level wow that's a lot of it you + + align:start position:0% +level level wow that's a lot of it you + + + align:start position:0% +level level wow that's a lot of it you +know what well but you are gonna charge + + align:start position:0% +know what well but you are gonna charge + + + align:start position:0% +know what well but you are gonna charge +the place in one round because each + + align:start position:0% +the place in one round because each + + + align:start position:0% +the place in one round because each +round is pretty fast + + align:start position:0% +round is pretty fast + + + align:start position:0% +round is pretty fast +so what stop with with you and then + + align:start position:0% +so what stop with with you and then + + + align:start position:0% +so what stop with with you and then +we'll go on okay and then everybody else + + align:start position:0% +we'll go on okay and then everybody else + + + align:start position:0% +we'll go on okay and then everybody else +pay attention because I guess he's + + align:start position:0% +pay attention because I guess he's + + + align:start position:0% +pay attention because I guess he's +pretty much played to the janitorial + + align:start position:0% +pretty much played to the janitorial + + + align:start position:0% +pretty much played to the janitorial +level so it's all it was all juried the + + align:start position:0% +level so it's all it was all juried the + + + align:start position:0% +level so it's all it was all juried the +design for the PC and was actually one + + align:start position:0% +design for the PC and was actually one + + + align:start position:0% +design for the PC and was actually one +of the it came out roughly you can't + + align:start position:0% +of the it came out roughly you can't + + + align:start position:0% +of the it came out roughly you can't +just go ahead and play it came out + + align:start position:0% +just go ahead and play it came out + + + align:start position:0% +just go ahead and play it came out +roughly about the same time as casual + + align:start position:0% +roughly about the same time as casual + + + align:start position:0% +roughly about the same time as casual +games downloadable casual games started + + align:start position:0% +games downloadable casual games started + + + align:start position:0% +games downloadable casual games started +picking up on on the pocket this was I + + align:start position:0% +picking up on on the pocket this was I + + + align:start position:0% +picking up on on the pocket this was I +don't think that was ever sold as a + + align:start position:0% +don't think that was ever sold as a + + + align:start position:0% +don't think that was ever sold as a +cross product or if it was that really + + align:start position:0% +cross product or if it was that really + + + align:start position:0% +cross product or if it was that really +was at the point of its business model + + align:start position:0% + + + + align:start position:0% + +so you you click around + + align:start position:0% + + + + align:start position:0% + +that already searched + + align:start position:0% + + + + align:start position:0% + +hello not gonna get + + align:start position:0% + + + + align:start position:0% + +you should use + + align:start position:0% + + + + align:start position:0% + +so though though resort rates are going + + align:start position:0% +so though though resort rates are going + + + align:start position:0% +so though though resort rates are going +down + + align:start position:0% +down + + + align:start position:0% +down +[Music] + + align:start position:0% + + + + align:start position:0% + +they like music darling okay big shiny + + align:start position:0% +they like music darling okay big shiny + + + align:start position:0% +they like music darling okay big shiny +thing how do we increase population + + align:start position:0% + + + + align:start position:0% + +yay look what this guy is down there so + + align:start position:0% +yay look what this guy is down there so + + + align:start position:0% +yay look what this guy is down there so +this this actually turns out not to be + + align:start position:0% +this this actually turns out not to be + + + align:start position:0% +this this actually turns out not to be +the tutorial level this just a thought + + align:start position:0% +the tutorial level this just a thought + + + align:start position:0% +the tutorial level this just a thought +to be the first level that's true + + align:start position:0% +to be the first level that's true + + + align:start position:0% +to be the first level that's true +people don't like late tutorials is true + + align:start position:0% + + + + align:start position:0% + +you have 22 times about to - barbarian + + align:start position:0% +you have 22 times about to - barbarian + + + align:start position:0% +you have 22 times about to - barbarian +hordes arriving + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +oh I did something clever okay + + align:start position:0% + + + + align:start position:0% + +I don't know I do have a smoke here + + align:start position:0% +I don't know I do have a smoke here + + + align:start position:0% +I don't know I do have a smoke here +March things go bad + + align:start position:0% +March things go bad + + + align:start position:0% +March things go bad +my parents are coming to a city to move + + align:start position:0% +my parents are coming to a city to move + + + align:start position:0% +my parents are coming to a city to move +troops they're here yeah you're learning + + align:start position:0% +troops they're here yeah you're learning + + + align:start position:0% +troops they're here yeah you're learning +feel the learning + + align:start position:0% + + + + align:start position:0% + +I think I want what did they do + + align:start position:0% +I think I want what did they do + + + align:start position:0% +I think I want what did they do +oh I saw it okay so you did in fact + + align:start position:0% +oh I saw it okay so you did in fact + + + align:start position:0% +oh I saw it okay so you did in fact +complete the level but yeah probably + + align:start position:0% +complete the level but yeah probably + + + align:start position:0% +complete the level but yeah probably +what happened here touching squares + + align:start position:0% + + + + align:start position:0% + +search okay that's okay + + align:start position:0% +search okay that's okay + + + align:start position:0% +search okay that's okay +steps that's what you figured out what + + align:start position:0% +steps that's what you figured out what + + + align:start position:0% +steps that's what you figured out what +about the rules but how do you + + align:start position:0% +about the rules but how do you + + + align:start position:0% +about the rules but how do you +personally feel about this game I mean + + align:start position:0% +personally feel about this game I mean + + + align:start position:0% +personally feel about this game I mean +glad that you already pick one one one + + align:start position:0% +glad that you already pick one one one + + + align:start position:0% +glad that you already pick one one one +level and clearly the game goes on okay + + align:start position:0% +level and clearly the game goes on okay + + + align:start position:0% +level and clearly the game goes on okay +alright so if you psychics out of your + + align:start position:0% +alright so if you psychics out of your + + + align:start position:0% +alright so if you psychics out of your +control + + align:start position:0% +control + + + align:start position:0% +control +yeah okay so so so back up lack of + + align:start position:0% +yeah okay so so so back up lack of + + + align:start position:0% +yeah okay so so so back up lack of +influence influence or possibly lack of + + align:start position:0% +influence influence or possibly lack of + + + align:start position:0% +influence influence or possibly lack of +control something of that all right so + + align:start position:0% +control something of that all right so + + + align:start position:0% +control something of that all right so +the next person providing themselves so + + align:start position:0% +the next person providing themselves so + + + align:start position:0% +the next person providing themselves so +young makes you're gonna play that level + + align:start position:0% +young makes you're gonna play that level + + + align:start position:0% +young makes you're gonna play that level +two taking it everything that you've + + align:start position:0% +two taking it everything that you've + + + align:start position:0% +two taking it everything that you've +seen so far + + align:start position:0% + + + + align:start position:0% + +I'm purple area of course anyone has any + + align:start position:0% +I'm purple area of course anyone has any + + + align:start position:0% +I'm purple area of course anyone has any +ideas about what he should be doing go + + align:start position:0% +ideas about what he should be doing go + + + align:start position:0% +ideas about what he should be doing go +ahead and say so he's other types of + + align:start position:0% +ahead and say so he's other types of + + + align:start position:0% +ahead and say so he's other types of +plate as I'm doing this yeah that's + + align:start position:0% +plate as I'm doing this yeah that's + + + align:start position:0% +plate as I'm doing this yeah that's +right but then I'm going to put up + + align:start position:0% +right but then I'm going to put up + + + align:start position:0% +right but then I'm going to put up +myself + + align:start position:0% +myself + + + align:start position:0% +myself +oh no do it in one turn straight you'd + + align:start position:0% +oh no do it in one turn straight you'd + + + align:start position:0% +oh no do it in one turn straight you'd +you go one purple square at a time yeah + + align:start position:0% +you go one purple square at a time yeah + + + align:start position:0% +you go one purple square at a time yeah +but I'm saying I want to control the + + align:start position:0% +but I'm saying I want to control the + + + align:start position:0% +but I'm saying I want to control the +squares up underneath that mountain does + + align:start position:0% +squares up underneath that mountain does + + + align:start position:0% +squares up underneath that mountain does +something okay what you people saying + + align:start position:0% +something okay what you people saying + + + align:start position:0% +something okay what you people saying +that there's wave when he put 20 people + + align:start position:0% +that there's wave when he put 20 people + + + align:start position:0% +that there's wave when he put 20 people +when when when you click on the mine + + align:start position:0% +when when when you click on the mine + + + align:start position:0% +when when when you click on the mine +what what do you think have it okay go + + align:start position:0% +what what do you think have it okay go + + + align:start position:0% +what what do you think have it okay go +go ahead hit do whatever you people I + + align:start position:0% +go ahead hit do whatever you people I + + + align:start position:0% +go ahead hit do whatever you people I +don't know I waste turns + + align:start position:0% + + + + align:start position:0% + +still one turn but does follow yeah yeah + + align:start position:0% +still one turn but does follow yeah yeah + + + align:start position:0% +still one turn but does follow yeah yeah +ooh but I got something I got archery + + align:start position:0% +ooh but I got something I got archery + + + align:start position:0% +ooh but I got something I got archery +I like archery bows increase your chance + + align:start position:0% +I like archery bows increase your chance + + + align:start position:0% +I like archery bows increase your chance +of 13 damage and the barbarians good + + align:start position:0% +of 13 damage and the barbarians good + + + align:start position:0% +of 13 damage and the barbarians good +keep doing that stuff I'm huge city city + + align:start position:0% +keep doing that stuff I'm huge city city + + + align:start position:0% +keep doing that stuff I'm huge city city +and get over look at that I don't know + + align:start position:0% +and get over look at that I don't know + + + align:start position:0% +and get over look at that I don't know +what that means but you found another + + align:start position:0% +what that means but you found another + + + align:start position:0% +what that means but you found another +technology it looks like I have no idea + + align:start position:0% +technology it looks like I have no idea + + + align:start position:0% +technology it looks like I have no idea +what the hell this Oh another city + + align:start position:0% +what the hell this Oh another city + + + align:start position:0% +what the hell this Oh another city +greetings at least two cities five I'll + + align:start position:0% +greetings at least two cities five I'll + + + align:start position:0% +greetings at least two cities five I'll +join your cause okay you can tell the + + align:start position:0% +join your cause okay you can tell the + + + align:start position:0% +join your cause okay you can tell the +doctors damn it oh good another city I + + align:start position:0% +doctors damn it oh good another city I + + + align:start position:0% +doctors damn it oh good another city I +should have certain look you got no + + align:start position:0% +should have certain look you got no + + + align:start position:0% +should have certain look you got no +technology than I did very nice very + + align:start position:0% +technology than I did very nice very + + + align:start position:0% +technology than I did very nice very +soon recess city projections the city to + + align:start position:0% +soon recess city projections the city to + + + align:start position:0% +soon recess city projections the city to +might survive cause he's defending a + + align:start position:0% +might survive cause he's defending a + + + align:start position:0% +might survive cause he's defending a +second city + + align:start position:0% +second city + + + align:start position:0% +second city +I think I think I think you mean before + + align:start position:0% +I think I think I think you mean before + + + align:start position:0% +I think I think I think you mean before +class started yeah okay so you feel + + align:start position:0% +class started yeah okay so you feel + + + align:start position:0% +class started yeah okay so you feel +awesome but you still don't know what I + + align:start position:0% +awesome but you still don't know what I + + + align:start position:0% +awesome but you still don't know what I +do know explore he's very good okay so + + align:start position:0% +do know explore he's very good okay so + + + align:start position:0% +do know explore he's very good okay so +here that one out so that's some sort of + + align:start position:0% +here that one out so that's some sort of + + + align:start position:0% +here that one out so that's some sort of +like exploring all right + + align:start position:0% + + + + align:start position:0% + +okay figure out how to build a road + + align:start position:0% +okay figure out how to build a road + + + align:start position:0% +okay figure out how to build a road +he'll talk dirty with that dot for + + align:start position:0% +he'll talk dirty with that dot for + + + align:start position:0% +he'll talk dirty with that dot for +something yeah we don't know oh okay + + align:start position:0% +something yeah we don't know oh okay + + + align:start position:0% +something yeah we don't know oh okay +plus 20 starting villagers that's huge + + align:start position:0% +plus 20 starting villagers that's huge + + + align:start position:0% +plus 20 starting villagers that's huge +and mother set the fuse bomb + + align:start position:0% +and mother set the fuse bomb + + + align:start position:0% +and mother set the fuse bomb +hey perfect click it again always + + align:start position:0% +hey perfect click it again always + + + align:start position:0% +hey perfect click it again always +temples have a city that did nothing + + align:start position:0% + + + + align:start position:0% + +mines + + align:start position:0% + + + + align:start position:0% + +what are those two temple mount's do you + + align:start position:0% +what are those two temple mount's do you + + + align:start position:0% +what are those two temple mount's do you +wanna check that out + + align:start position:0% +wanna check that out + + + align:start position:0% +wanna check that out +oh okay so I think I figured out the + + align:start position:0% +oh okay so I think I figured out the + + + align:start position:0% +oh okay so I think I figured out the +money's at the bottom that's like oh + + align:start position:0% +money's at the bottom that's like oh + + + align:start position:0% +money's at the bottom that's like oh +yeah oh so you want to increase mines so + + align:start position:0% +yeah oh so you want to increase mines so + + + align:start position:0% +yeah oh so you want to increase mines so +you put more bad would buy that it's a + + align:start position:0% +you put more bad would buy that it's a + + + align:start position:0% +you put more bad would buy that it's a +multiplier yeah did you build a road + + align:start position:0% +multiplier yeah did you build a road + + + align:start position:0% +multiplier yeah did you build a road +how'd you do that how do build a road + + align:start position:0% +how'd you do that how do build a road + + + align:start position:0% +how'd you do that how do build a road +just like on the five hours I only need + + align:start position:0% +just like on the five hours I only need + + + align:start position:0% +just like on the five hours I only need +followers to kasi followers to do so + + align:start position:0% +followers to kasi followers to do so + + + align:start position:0% +followers to kasi followers to do so +okay + + align:start position:0% +okay + + + align:start position:0% +okay +get more followers and Bill Gross later + + align:start position:0% +get more followers and Bill Gross later + + + align:start position:0% +get more followers and Bill Gross later +what follows can you say bro you also + + align:start position:0% +what follows can you say bro you also + + + align:start position:0% +what follows can you say bro you also +put them inside the mines how does he + + align:start position:0% +put them inside the mines how does he + + + align:start position:0% +put them inside the mines how does he +have multiple options that you can do + + align:start position:0% +have multiple options that you can do + + + align:start position:0% +have multiple options that you can do +with your followers did you ever + + align:start position:0% +with your followers did you ever + + + align:start position:0% +with your followers did you ever +searched your upper city where you have + + align:start position:0% +searched your upper city where you have + + + align:start position:0% +searched your upper city where you have +46 people now the populations only + + align:start position:0% +46 people now the populations only + + + align:start position:0% +46 people now the populations only +points on the first level finding the + + align:start position:0% +points on the first level finding the + + + align:start position:0% +points on the first level finding the +whole river good including the police + + align:start position:0% +whole river good including the police + + + align:start position:0% +whole river good including the police +yeah the point may take you a letter oh + + align:start position:0% +yeah the point may take you a letter oh + + + align:start position:0% +yeah the point may take you a letter oh +so + + align:start position:0% + + + + align:start position:0% + +Hey look at that + + align:start position:0% +Hey look at that + + + align:start position:0% +Hey look at that +now you never that's it it's like + + align:start position:0% +now you never that's it it's like + + + align:start position:0% +now you never that's it it's like +pitbull oh yeah more cities by the way + + align:start position:0% +pitbull oh yeah more cities by the way + + + align:start position:0% +pitbull oh yeah more cities by the way +that looks like a pathway through Oh + + align:start position:0% +that looks like a pathway through Oh + + + align:start position:0% +that looks like a pathway through Oh +perfect give a new mind you a new + + align:start position:0% +perfect give a new mind you a new + + + align:start position:0% +perfect give a new mind you a new +population + + align:start position:0% +population + + + align:start position:0% +population +you've now rope going downward help + + align:start position:0% +you've now rope going downward help + + + align:start position:0% +you've now rope going downward help +don't forget to put men just that mind + + align:start position:0% +don't forget to put men just that mind + + + align:start position:0% +don't forget to put men just that mind +you're 20 turns valium to insurance 251 + + align:start position:0% +you're 20 turns valium to insurance 251 + + + align:start position:0% +you're 20 turns valium to insurance 251 +City increasing all right you're just + + align:start position:0% +City increasing all right you're just + + + align:start position:0% +City increasing all right you're just +made it nice + + align:start position:0% +made it nice + + + align:start position:0% +made it nice +did you search that I do to followers in + + align:start position:0% +did you search that I do to followers in + + + align:start position:0% +did you search that I do to followers in +the mind that pop I don't do too much + + align:start position:0% +the mind that pop I don't do too much + + + align:start position:0% +the mind that pop I don't do too much +he's yet to find oh good you found one + + align:start position:0% +he's yet to find oh good you found one + + + align:start position:0% +he's yet to find oh good you found one +of the upper symbols yeah we don't know + + align:start position:0% +of the upper symbols yeah we don't know + + + align:start position:0% +of the upper symbols yeah we don't know +another Corgi I'm looking for Emily and + + align:start position:0% +another Corgi I'm looking for Emily and + + + align:start position:0% +another Corgi I'm looking for Emily and +in the bottom right to the top left the + + align:start position:0% +in the bottom right to the top left the + + + align:start position:0% +in the bottom right to the top left the +only ones up here + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% + + + + align:start position:0% + +oh all three now can you connect roads + + align:start position:0% +oh all three now can you connect roads + + + align:start position:0% +oh all three now can you connect roads +in time you two turns no house for the + + align:start position:0% +in time you two turns no house for the + + + align:start position:0% +in time you two turns no house for the +last two trips put your followers in + + align:start position:0% +last two trips put your followers in + + + align:start position:0% +last two trips put your followers in +your mind there's a last technology + + align:start position:0% +your mind there's a last technology + + + align:start position:0% +your mind there's a last technology +Minotauro in sir it's fine I don't think + + align:start position:0% +Minotauro in sir it's fine I don't think + + + align:start position:0% +Minotauro in sir it's fine I don't think +I'll have enough to do that I'm okay but + + align:start position:0% + + + + align:start position:0% + +firstly the British disease is possible + + align:start position:0% +firstly the British disease is possible + + + align:start position:0% +firstly the British disease is possible +you need more technology also this like + + align:start position:0% +you need more technology also this like + + + align:start position:0% +you need more technology also this like +how ok so if you if you like like like + + align:start position:0% +how ok so if you if you like like like + + + align:start position:0% +how ok so if you if you like like like +you like you salvation + + align:start position:0% +you like you salvation + + + align:start position:0% +you like you salvation +what's that volunteer I thought I saw + + align:start position:0% +what's that volunteer I thought I saw + + + align:start position:0% +what's that volunteer I thought I saw +four hands + + align:start position:0% +four hands + + + align:start position:0% +four hands +try it one more time + + align:start position:0% + + + + align:start position:0% + +put everyone online + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% + + + + align:start position:0% + +that's do we search the US + + align:start position:0% +that's do we search the US + + + align:start position:0% +that's do we search the US +[Music] + + align:start position:0% + + + + align:start position:0% + +is it valuable to build rows in between + + align:start position:0% +is it valuable to build rows in between + + + align:start position:0% +is it valuable to build rows in between +lines and cities + + align:start position:0% +lines and cities + + + align:start position:0% +lines and cities +don't think + + align:start position:0% +don't think + + + align:start position:0% +don't think +okay + + align:start position:0% +okay + + + align:start position:0% +okay +all right now you go through that + + align:start position:0% +all right now you go through that + + + align:start position:0% +all right now you go through that +passage I see the arc yeah they don't + + align:start position:0% +passage I see the arc yeah they don't + + + align:start position:0% +passage I see the arc yeah they don't +get to searches see what you got oh look + + align:start position:0% +get to searches see what you got oh look + + + align:start position:0% +get to searches see what you got oh look +at that very nice tiny population + + align:start position:0% +at that very nice tiny population + + + align:start position:0% +at that very nice tiny population +increase probably want to get see cities + + align:start position:0% +increase probably want to get see cities + + + align:start position:0% +increase probably want to get see cities +first into the Oasis last night you + + align:start position:0% +first into the Oasis last night you + + + align:start position:0% +first into the Oasis last night you +better be Oh keep going up there was + + align:start position:0% +better be Oh keep going up there was + + + align:start position:0% +better be Oh keep going up there was +something there + + align:start position:0% + + + + align:start position:0% + +all right he searched the city bus + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% + + + + align:start position:0% + +you're just jumping all over the place + + align:start position:0% + + + + align:start position:0% + +seas gaily to offers + + align:start position:0% +seas gaily to offers + + + align:start position:0% +seas gaily to offers +oh I'm waiting on your cities + + align:start position:0% +oh I'm waiting on your cities + + + align:start position:0% +oh I'm waiting on your cities +no you just never know sitting there + + align:start position:0% +no you just never know sitting there + + + align:start position:0% +no you just never know sitting there +make a city dump all your juicy operator + + align:start position:0% +make a city dump all your juicy operator + + + align:start position:0% +make a city dump all your juicy operator +bottom left just 220 units that's very + + align:start position:0% +bottom left just 220 units that's very + + + align:start position:0% +bottom left just 220 units that's very +nice nice you got at least three + + align:start position:0% +nice nice you got at least three + + + align:start position:0% +nice nice you got at least three +technology + + align:start position:0% + + + + align:start position:0% + +oh yeah + + align:start position:0% +oh yeah + + + align:start position:0% +oh yeah +[Music] + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% + + + + align:start position:0% + +okay all right so so you feel that there + + align:start position:0% +okay all right so so you feel that there + + + align:start position:0% +okay all right so so you feel that there +are some there's some redundancy going + + align:start position:0% +are some there's some redundancy going + + + align:start position:0% +are some there's some redundancy going +though yeah okay all right all right + + align:start position:0% +though yeah okay all right all right + + + align:start position:0% +though yeah okay all right all right +cool thank you thank you thank you very + + align:start position:0% +cool thank you thank you thank you very + + + align:start position:0% +cool thank you thank you thank you very +much so these are kinds of the things + + align:start position:0% +much so these are kinds of the things + + + align:start position:0% +much so these are kinds of the things +that ask players you know the sensations + + align:start position:0% +that ask players you know the sensations + + + align:start position:0% +that ask players you know the sensations +that you get right you know you get kind + + align:start position:0% +that you get right you know you get kind + + + align:start position:0% +that you get right you know you get kind +of like a joy of exploring you know + + align:start position:0% +of like a joy of exploring you know + + + align:start position:0% +of like a joy of exploring you know +finding out new things pushing back to + + align:start position:0% +finding out new things pushing back to + + + align:start position:0% +finding out new things pushing back to +funk at the beginning of learning a game + + align:start position:0% +funk at the beginning of learning a game + + + align:start position:0% +funk at the beginning of learning a game +you know this confusion that's before + + align:start position:0% +you know this confusion that's before + + + align:start position:0% +you know this confusion that's before +the ones you don't actually know how + + align:start position:0% +the ones you don't actually know how + + + align:start position:0% +the ones you don't actually know how +your actions are you know changing + + align:start position:0% +your actions are you know changing + + + align:start position:0% +your actions are you know changing +things but if you play a lot of games + + align:start position:0% +things but if you play a lot of games + + + align:start position:0% +things but if you play a lot of games +you usually sort of primed to sort of + + align:start position:0% +you usually sort of primed to sort of + + + align:start position:0% +you usually sort of primed to sort of +accept a little bit of that and + + align:start position:0% +accept a little bit of that and + + + align:start position:0% +accept a little bit of that and +sometimes it's it's balanced well enough + + align:start position:0% +sometimes it's it's balanced well enough + + + align:start position:0% +sometimes it's it's balanced well enough +that it's sort of it feeds you rather + + align:start position:0% +that it's sort of it feeds you rather + + + align:start position:0% +that it's sort of it feeds you rather +than you know puts you off but sometimes + + align:start position:0% +than you know puts you off but sometimes + + + align:start position:0% +than you know puts you off but sometimes +it just puts you off somewhat said that + + align:start position:0% +it just puts you off somewhat said that + + + align:start position:0% +it just puts you off somewhat said that +was a it felt good to save people you + + align:start position:0% +was a it felt good to save people you + + + align:start position:0% +was a it felt good to save people you +know best there's that you described it + + align:start position:0% +know best there's that you described it + + + align:start position:0% +know best there's that you described it +as feeling kind of fun and in the paper + + align:start position:0% +as feeling kind of fun and in the paper + + + align:start position:0% +as feeling kind of fun and in the paper +some different ways how we can some + + align:start position:0% +some different ways how we can some + + + align:start position:0% +some different ways how we can some +describe fun you know the the it's just + + align:start position:0% +describe fun you know the the it's just + + + align:start position:0% +describe fun you know the the it's just +eight different types but even in a + + align:start position:0% +eight different types but even in a + + + align:start position:0% +eight different types but even in a +paper it states it isn't meant to be a + + align:start position:0% +paper it states it isn't meant to be a + + + align:start position:0% +paper it states it isn't meant to be a +comprehensive place is it where to be a + + align:start position:0% +comprehensive place is it where to be a + + + align:start position:0% +comprehensive place is it where to be a +list that's just exhausting every single + + align:start position:0% +list that's just exhausting every single + + + align:start position:0% +list that's just exhausting every single +op a kind of fun out there it's just + + align:start position:0% +op a kind of fun out there it's just + + + align:start position:0% +op a kind of fun out there it's just +there to show that there's a lot of + + align:start position:0% +there to show that there's a lot of + + + align:start position:0% +there to show that there's a lot of +different kinds of fun when you when you + + align:start position:0% +different kinds of fun when you when you + + + align:start position:0% +different kinds of fun when you when you +play a game like exploring things well + + align:start position:0% +play a game like exploring things well + + + align:start position:0% +play a game like exploring things well +you know inhabiting a role or overcoming + + align:start position:0% +you know inhabiting a role or overcoming + + + align:start position:0% +you know inhabiting a role or overcoming +a challenge or just you know passing + + align:start position:0% +a challenge or just you know passing + + + align:start position:0% +a challenge or just you know passing +time in a you know in + + align:start position:0% +time in a you know in + + + align:start position:0% +time in a you know in +in a way to alleviate boredom sorry I + + align:start position:0% +in a way to alleviate boredom sorry I + + + align:start position:0% +in a way to alleviate boredom sorry I +have a bit of cold so my my speeches a + + align:start position:0% +have a bit of cold so my my speeches a + + + align:start position:0% +have a bit of cold so my my speeches a +little bit under today there is there + + align:start position:0% +little bit under today there is there + + + align:start position:0% +little bit under today there is there +are a number of game mechanics in here + + align:start position:0% +are a number of game mechanics in here + + + align:start position:0% +are a number of game mechanics in here +that generate some of these sensations + + align:start position:0% +that generate some of these sensations + + + align:start position:0% +that generate some of these sensations +I'm going to put aside stuff about + + align:start position:0% +I'm going to put aside stuff about + + + align:start position:0% +I'm going to put aside stuff about +confusion and lack of all influence + + align:start position:0% +confusion and lack of all influence + + + align:start position:0% +confusion and lack of all influence +right now because some of that addressed + + align:start position:0% +right now because some of that addressed + + + align:start position:0% +right now because some of that addressed +in a tutorial is like if you if if you + + align:start position:0% +in a tutorial is like if you if if you + + + align:start position:0% +in a tutorial is like if you if if you +went through the tutorial and explain to + + align:start position:0% +went through the tutorial and explain to + + + align:start position:0% +went through the tutorial and explain to +you what all the actions were you + + align:start position:0% +you what all the actions were you + + + align:start position:0% +you what all the actions were you +probably wouldn't feel quite so confused + + align:start position:0% +probably wouldn't feel quite so confused + + + align:start position:0% +probably wouldn't feel quite so confused +about what you could do however I think + + align:start position:0% +about what you could do however I think + + + align:start position:0% +about what you could do however I think +it's reasonable to sort of address the + + align:start position:0% +it's reasonable to sort of address the + + + align:start position:0% +it's reasonable to sort of address the +lack of control that you might feel even + + align:start position:0% +lack of control that you might feel even + + + align:start position:0% +lack of control that you might feel even +after knowing what you could do right so + + align:start position:0% +after knowing what you could do right so + + + align:start position:0% +after knowing what you could do right so +let's talk about but that's right these + + align:start position:0% +let's talk about but that's right these + + + align:start position:0% +let's talk about but that's right these +are the things that the people will + + align:start position:0% +are the things that the people will + + + align:start position:0% +are the things that the people will +describe as aesthetics the thing that + + align:start position:0% +describe as aesthetics the thing that + + + align:start position:0% +describe as aesthetics the thing that +the player feels whether the the paper + + align:start position:0% +the player feels whether the the paper + + + align:start position:0% +the player feels whether the the paper +describes them as desirable experiences + + align:start position:0% +describes them as desirable experiences + + + align:start position:0% +describes them as desirable experiences +that's not necessarily always the case + + align:start position:0% +that's not necessarily always the case + + + align:start position:0% +that's not necessarily always the case +it's not always desirable I mean I'm + + align:start position:0% +it's not always desirable I mean I'm + + + align:start position:0% +it's not always desirable I mean I'm +pretty sure + + align:start position:0% +pretty sure + + + align:start position:0% +pretty sure +confusion was not a desire what was was + + align:start position:0% +confusion was not a desire what was was + + + align:start position:0% +confusion was not a desire what was was +not a desire experience that the + + align:start position:0% +not a desire experience that the + + + align:start position:0% +not a desire experience that the +designer of this game wanted you to have + + align:start position:0% +designer of this game wanted you to have + + + align:start position:0% +designer of this game wanted you to have +by the way one of the designers of that + + align:start position:0% +by the way one of the designers of that + + + align:start position:0% +by the way one of the designers of that +game is actually also one of the writers + + align:start position:0% +game is actually also one of the writers + + + align:start position:0% +game is actually also one of the writers +of this paper which is why we're playing + + align:start position:0% +of this paper which is why we're playing + + + align:start position:0% +of this paper which is why we're playing +this game in particular so these are + + align:start position:0% +this game in particular so these are + + + align:start position:0% +this game in particular so these are +aesthetics let's talk about some of the + + align:start position:0% +aesthetics let's talk about some of the + + + align:start position:0% +aesthetics let's talk about some of the +mechanics of the game execution of the + + align:start position:0% +mechanics of the game execution of the + + + align:start position:0% +mechanics of the game execution of the +screen uh trigger + + align:start position:0% + + + + align:start position:0% + +so let's talk about some other mechanics + + align:start position:0% +so let's talk about some other mechanics + + + align:start position:0% +so let's talk about some other mechanics +in this game well someone described it + + align:start position:0% +in this game well someone described it + + + align:start position:0% +in this game well someone described it +this right + + align:start position:0% + + + + align:start position:0% + +okay so + + align:start position:0% + + + + align:start position:0% + +okay alright so so it's turn-based until + + align:start position:0% +okay alright so so it's turn-based until + + + align:start position:0% +okay alright so so it's turn-based until +use this until you've made your final + + align:start position:0% +use this until you've made your final + + + align:start position:0% +use this until you've made your final +move right and then that's ten seconds + + align:start position:0% +move right and then that's ten seconds + + + align:start position:0% +move right and then that's ten seconds +when it counts down as you see things + + align:start position:0% +when it counts down as you see things + + + align:start position:0% +when it counts down as you see things +continue to happen + + align:start position:0% +continue to happen + + + align:start position:0% +continue to happen +okay all right there is called badness + + align:start position:0% +okay all right there is called badness + + + align:start position:0% +okay all right there is called badness +of mechanicus that's some sort of a I + + align:start position:0% +of mechanicus that's some sort of a I + + + align:start position:0% +of mechanicus that's some sort of a I +call back right + + align:start position:0% +call back right + + + align:start position:0% +call back right +you don't actually directly tell tell + + align:start position:0% +you don't actually directly tell tell + + + align:start position:0% +you don't actually directly tell tell +your troops to attack you to face that + + align:start position:0% +your troops to attack you to face that + + + align:start position:0% +your troops to attack you to face that +ahead of time and then they just wail at + + align:start position:0% +ahead of time and then they just wail at + + + align:start position:0% +ahead of time and then they just wail at +each other using some sort of algorithm + + align:start position:0% +each other using some sort of algorithm + + + align:start position:0% +each other using some sort of algorithm +some sort of computation of who are on + + align:start position:0% +some sort of computation of who are on + + + align:start position:0% +some sort of computation of who are on +how the numbers of how the magician + + align:start position:0% +how the numbers of how the magician + + + align:start position:0% +how the numbers of how the magician +works what else is in the game + + align:start position:0% + + + + align:start position:0% + +declaration so go ahead make that say + + align:start position:0% +declaration so go ahead make that say + + + align:start position:0% +declaration so go ahead make that say +you're like okay so so how do you find + + align:start position:0% +you're like okay so so how do you find + + + align:start position:0% +you're like okay so so how do you find +cities how do you find city okay so so + + align:start position:0% +cities how do you find city okay so so + + + align:start position:0% +cities how do you find city okay so so +you you you click on the purple squares + + align:start position:0% +you you you click on the purple squares + + + align:start position:0% +you you you click on the purple squares +right and then that shows you what's + + align:start position:0% +right and then that shows you what's + + + align:start position:0% +right and then that shows you what's +underneath the purple square basically + + align:start position:0% +underneath the purple square basically + + + align:start position:0% +underneath the purple square basically +the fog so so that's they've got a sort + + align:start position:0% +the fog so so that's they've got a sort + + + align:start position:0% +the fog so so that's they've got a sort +of it's not full of war exactly but you + + align:start position:0% +of it's not full of war exactly but you + + + align:start position:0% +of it's not full of war exactly but you +know they've got a sort of uh unexplored + + align:start position:0% +know they've got a sort of uh unexplored + + + align:start position:0% +know they've got a sort of uh unexplored +fog right which you tap to to disappear + + align:start position:0% +fog right which you tap to to disappear + + + align:start position:0% +fog right which you tap to to disappear +is that the only clue about how to find + + align:start position:0% +is that the only clue about how to find + + + align:start position:0% +is that the only clue about how to find +a city sometimes you can be deposited + + align:start position:0% +a city sometimes you can be deposited + + + align:start position:0% +a city sometimes you can be deposited +right there's something there yeah + + align:start position:0% + + + + align:start position:0% + +on speed but on the iPad defines all + + align:start position:0% +on speed but on the iPad defines all + + + align:start position:0% +on speed but on the iPad defines all +these cities so if you step on something + + align:start position:0% +these cities so if you step on something + + + align:start position:0% +these cities so if you step on something +greed in the city somewhere nearby + + align:start position:0% +greed in the city somewhere nearby + + + align:start position:0% +greed in the city somewhere nearby +instead of mine sweepers to doesn't what + + align:start position:0% +instead of mine sweepers to doesn't what + + + align:start position:0% +instead of mine sweepers to doesn't what +else deal with okay so what what about + + align:start position:0% +else deal with okay so what what about + + + align:start position:0% +else deal with okay so what what about +you + + align:start position:0% +you + + + align:start position:0% +you +looking for it and as soon as you hit + + align:start position:0% +looking for it and as soon as you hit + + + align:start position:0% +looking for it and as soon as you hit +one of the squares of those you be more + + align:start position:0% +one of the squares of those you be more + + + align:start position:0% +one of the squares of those you be more +or less like figure out where the other + + align:start position:0% +or less like figure out where the other + + + align:start position:0% +or less like figure out where the other +ones are okay because it seems to always + + align:start position:0% +ones are okay because it seems to always + + + align:start position:0% +ones are okay because it seems to always +be in the same 3 by 4 yeah so so the + + align:start position:0% +be in the same 3 by 4 yeah so so the + + + align:start position:0% +be in the same 3 by 4 yeah so so the +Oasis creativity right like you feel + + align:start position:0% +Oasis creativity right like you feel + + + align:start position:0% +Oasis creativity right like you feel +like yeah well the Oasis is always a + + align:start position:0% +like yeah well the Oasis is always a + + + align:start position:0% +like yeah well the Oasis is always a +rectangle + + align:start position:0% +rectangle + + + align:start position:0% +rectangle +I'm sorry sorry so you find Carter yeah + + align:start position:0% +I'm sorry sorry so you find Carter yeah + + + align:start position:0% +I'm sorry sorry so you find Carter yeah +you know you know that if you follow + + align:start position:0% +you know you know that if you follow + + + align:start position:0% +you know you know that if you follow +what those things do you can see the tip + + align:start position:0% +what those things do you can see the tip + + + align:start position:0% +what those things do you can see the tip +as well like United plate + + align:start position:0% +as well like United plate + + + align:start position:0% +as well like United plate +it's either grass on this side water on + + align:start position:0% +it's either grass on this side water on + + + align:start position:0% +it's either grass on this side water on +this side right so so so if the grid was + + align:start position:0% +this side right so so so if the grid was + + + align:start position:0% +this side right so so so if the grid was +like that you know once the what would + + align:start position:0% +like that you know once the what would + + + align:start position:0% +like that you know once the what would +you find one corner you know which way + + align:start position:0% +you find one corner you know which way + + + align:start position:0% +you find one corner you know which way +to explore off the river so analysis + + align:start position:0% +to explore off the river so analysis + + + align:start position:0% +to explore off the river so analysis +gives you clues the title of the always + + align:start position:0% +gives you clues the title of the always + + + align:start position:0% +gives you clues the title of the always +does alone to give you clues in the same + + align:start position:0% +does alone to give you clues in the same + + + align:start position:0% +does alone to give you clues in the same +way that the farm to keep include upon + + align:start position:0% +way that the farm to keep include upon + + + align:start position:0% +way that the farm to keep include upon +decisions + + align:start position:0% + + + + align:start position:0% + +or bill groves or cities - how do you + + align:start position:0% +or bill groves or cities - how do you + + + align:start position:0% +or bill groves or cities - how do you +allocate resources in this game you just + + align:start position:0% +allocate resources in this game you just + + + align:start position:0% +allocate resources in this game you just +type it and what happens when you tap + + align:start position:0% + + + + align:start position:0% + +so you you have a limited number of + + align:start position:0% +so you you have a limited number of + + + align:start position:0% +so you you have a limited number of +followers and tapping assigns them to + + align:start position:0% +followers and tapping assigns them to + + + align:start position:0% +followers and tapping assigns them to +spend them basically to get to for + + align:start position:0% +spend them basically to get to for + + + align:start position:0% +spend them basically to get to for +follow some sort of some task so so + + align:start position:0% + + + + align:start position:0% + +followers for science science the + + align:start position:0% +followers for science science the + + + align:start position:0% +followers for science science the +followers okay other ones + + align:start position:0% + + + + align:start position:0% + +there's this work + + align:start position:0% +there's this work + + + align:start position:0% +there's this work +it's courting again which is different + + align:start position:0% +it's courting again which is different + + + align:start position:0% +it's courting again which is different +you know from what actually like when + + align:start position:0% +you know from what actually like when + + + align:start position:0% +you know from what actually like when +you add your level + + align:start position:0% +you add your level + + + align:start position:0% +you add your level +well there did your well and then + + align:start position:0% +well there did your well and then + + + align:start position:0% +well there did your well and then +like + + align:start position:0% +like + + + align:start position:0% +like +didn't always respond during this war + + align:start position:0% +didn't always respond during this war + + + align:start position:0% +didn't always respond during this war +right the score isn't necessary so the + + align:start position:0% +right the score isn't necessary so the + + + align:start position:0% +right the score isn't necessary so the +score is that the score has is kind of + + align:start position:0% +score is that the score has is kind of + + + align:start position:0% +score is that the score has is kind of +different from what you from from from + + align:start position:0% +different from what you from from from + + + align:start position:0% +different from what you from from from +from what engage immediately giving you + + align:start position:0% +from what engage immediately giving you + + + align:start position:0% +from what engage immediately giving you +feedback on this score is kind of like a + + align:start position:0% +feedback on this score is kind of like a + + + align:start position:0% +feedback on this score is kind of like a +completely different kind of feedback + + align:start position:0% + + + + align:start position:0% + +size was very confused when like we won + + align:start position:0% +size was very confused when like we won + + + align:start position:0% +size was very confused when like we won +first low because everyone died but we + + align:start position:0% +first low because everyone died but we + + + align:start position:0% +first low because everyone died but we +got four zero which kind of made sense + + align:start position:0% +got four zero which kind of made sense + + + align:start position:0% +got four zero which kind of made sense +then and like when I went above people + + align:start position:0% +then and like when I went above people + + + align:start position:0% +then and like when I went above people +died like so much level like that made + + align:start position:0% +died like so much level like that made + + + align:start position:0% +died like so much level like that made +sense bad two cities left I still got + + align:start position:0% +sense bad two cities left I still got + + + align:start position:0% +sense bad two cities left I still got +score zero because I lost tons of people + + align:start position:0% +score zero because I lost tons of people + + + align:start position:0% +score zero because I lost tons of people +then when we made it so we didn't lose a + + align:start position:0% +then when we made it so we didn't lose a + + + align:start position:0% +then when we made it so we didn't lose a +single City we got the exported house or + + align:start position:0% +single City we got the exported house or + + + align:start position:0% +single City we got the exported house or +something + + align:start position:0% + + + + align:start position:0% + +I know the score makes sense + + align:start position:0% +I know the score makes sense + + + align:start position:0% +I know the score makes sense +maybe the level progression in person + + align:start position:0% + + + + align:start position:0% + +yes we love I said you've added you know + + align:start position:0% + + + + align:start position:0% + +there you go + + align:start position:0% + + + + align:start position:0% + +patience and a score for foreground to + + align:start position:0% +patience and a score for foreground to + + + align:start position:0% +patience and a score for foreground to +be equivalent standards and that's a + + align:start position:0% +be equivalent standards and that's a + + + align:start position:0% +be equivalent standards and that's a +perfectly find another truck + + align:start position:0% + + + + align:start position:0% + +I understand there was another mechanic + + align:start position:0% +I understand there was another mechanic + + + align:start position:0% +I understand there was another mechanic +we didn't really get to discover it but + + align:start position:0% +we didn't really get to discover it but + + + align:start position:0% +we didn't really get to discover it but +those of the link blowing Oh a right + + align:start position:0% +those of the link blowing Oh a right + + + align:start position:0% +those of the link blowing Oh a right +right right right + + align:start position:0% + + + + align:start position:0% + +clearly leading to something we haven't + + align:start position:0% +clearly leading to something we haven't + + + align:start position:0% +clearly leading to something we haven't +figured out yet okay there is no special + + align:start position:0% +figured out yet okay there is no special + + + align:start position:0% +figured out yet okay there is no special +power that we got that's okay yeah I + + align:start position:0% +power that we got that's okay yeah I + + + align:start position:0% +power that we got that's okay yeah I +think they called experts advice was + + align:start position:0% +think they called experts advice was + + + align:start position:0% +think they called experts advice was +that followers part of this because you + + align:start position:0% +that followers part of this because you + + + align:start position:0% +that followers part of this because you +know exactly how do with this yeah I got + + align:start position:0% +know exactly how do with this yeah I got + + + align:start position:0% +know exactly how do with this yeah I got +transported artwork right + + align:start position:0% +transported artwork right + + + align:start position:0% +transported artwork right +okay so when where did this go up to + + align:start position:0% +okay so when where did this go up to + + + align:start position:0% +okay so when where did this go up to +appeared anyone know this you're + + align:start position:0% +appeared anyone know this you're + + + align:start position:0% +appeared anyone know this you're +uncovering the tiles but when you + + align:start position:0% +uncovering the tiles but when you + + + align:start position:0% +uncovering the tiles but when you +searched if you didn't get when you pick + + align:start position:0% +searched if you didn't get when you pick + + + align:start position:0% +searched if you didn't get when you pick +up the always when you walk over the + + align:start position:0% +up the always when you walk over the + + + align:start position:0% +up the always when you walk over the +Oasis you get the worms so you always + + align:start position:0% +Oasis you get the worms so you always + + + align:start position:0% +Oasis you get the worms so you always +this also gives you just like the bluest + + align:start position:0% +this also gives you just like the bluest + + + align:start position:0% +this also gives you just like the bluest +thing on the screen we do click on it + + align:start position:0% +thing on the screen we do click on it + + + align:start position:0% +thing on the screen we do click on it +blue things move so there's some sort of + + align:start position:0% +blue things move so there's some sort of + + + align:start position:0% +blue things move so there's some sort of +like color coordination oh yes yes one + + align:start position:0% +like color coordination oh yes yes one + + + align:start position:0% +like color coordination oh yes yes one +time we got to be wait somethin happened + + align:start position:0% +time we got to be wait somethin happened + + + align:start position:0% +time we got to be wait somethin happened +everyone so so either the barbarians are + + align:start position:0% +everyone so so either the barbarians are + + + align:start position:0% +everyone so so either the barbarians are +taking away your blue or you're using + + align:start position:0% +taking away your blue or you're using + + + align:start position:0% +taking away your blue or you're using +your blue to smite the barbarians either + + align:start position:0% +your blue to smite the barbarians either + + + align:start position:0% +your blue to smite the barbarians either +way you end up with no barbarians and + + align:start position:0% +way you end up with no barbarians and + + + align:start position:0% +way you end up with no barbarians and +less blue right + + align:start position:0% + + + + align:start position:0% + +you will never for out like a 15 like + + align:start position:0% +you will never for out like a 15 like + + + align:start position:0% +you will never for out like a 15 like +yeah I can tell you one one of the + + align:start position:0% +yeah I can tell you one one of the + + + align:start position:0% +yeah I can tell you one one of the +things that this particular game + + align:start position:0% +things that this particular game + + + align:start position:0% +things that this particular game +designer has told me is that he doesn't + + align:start position:0% +designer has told me is that he doesn't + + + align:start position:0% +designer has told me is that he doesn't +believe in game balance he just believes + + align:start position:0% +believe in game balance he just believes + + + align:start position:0% +believe in game balance he just believes +in making a game starts so ridiculously + + align:start position:0% +in making a game starts so ridiculously + + + align:start position:0% +in making a game starts so ridiculously +easy and end and almost an impossible + + align:start position:0% +easy and end and almost an impossible + + + align:start position:0% +easy and end and almost an impossible +level so somewhere along the way you + + align:start position:0% +level so somewhere along the way you + + + align:start position:0% +level so somewhere along the way you +meet the level that you're good at and + + align:start position:0% +meet the level that you're good at and + + + align:start position:0% +meet the level that you're good at and +that's a balanced game that's that's one + + align:start position:0% +that's a balanced game that's that's one + + + align:start position:0% +that's a balanced game that's that's one +way of looking at it so so maybe fine + + align:start position:0% +way of looking at it so so maybe fine + + + align:start position:0% +way of looking at it so so maybe fine +okay fine a bunch of game mechanics we + + align:start position:0% +okay fine a bunch of game mechanics we + + + align:start position:0% +okay fine a bunch of game mechanics we +didn't go into things like roads and + + align:start position:0% +didn't go into things like roads and + + + align:start position:0% +didn't go into things like roads and +technologies and find this of it and + + align:start position:0% +technologies and find this of it and + + + align:start position:0% +technologies and find this of it and +there's a ton of game mechanics in here + + align:start position:0% +there's a ton of game mechanics in here + + + align:start position:0% +there's a ton of game mechanics in here +these are the kinds of things that a + + align:start position:0% +these are the kinds of things that a + + + align:start position:0% +these are the kinds of things that a +game designer can design right these are + + align:start position:0% +game designer can design right these are + + + align:start position:0% +game designer can design right these are +rules you know things as simple as you + + align:start position:0% +rules you know things as simple as you + + + align:start position:0% +rules you know things as simple as you +always say this always in a rectangle + + align:start position:0% +always say this always in a rectangle + + + align:start position:0% +always say this always in a rectangle +that's no reason for that it could have + + align:start position:0% +that's no reason for that it could have + + + align:start position:0% +that's no reason for that it could have +been a river but yeah but you're right + + align:start position:0% +been a river but yeah but you're right + + + align:start position:0% +been a river but yeah but you're right +that is actually a rule it every time + + align:start position:0% +that is actually a rule it every time + + + align:start position:0% +that is actually a rule it every time +you find always it's always going to be + + align:start position:0% +you find always it's always going to be + + + align:start position:0% +you find always it's always going to be +a rectangular shape these are the things + + align:start position:0% +a rectangular shape these are the things + + + align:start position:0% +a rectangular shape these are the things +that that the designer decides and you + + align:start position:0% +that that the designer decides and you + + + align:start position:0% +that that the designer decides and you +get dynamics well out of a bunch of + + align:start position:0% +get dynamics well out of a bunch of + + + align:start position:0% +get dynamics well out of a bunch of +these mechanics interacting with each + + align:start position:0% +these mechanics interacting with each + + + align:start position:0% +these mechanics interacting with each +other so I'm gonna give one example of a + + align:start position:0% +other so I'm gonna give one example of a + + + align:start position:0% +other so I'm gonna give one example of a +Titanic one of the dynamics is that as + + align:start position:0% +Titanic one of the dynamics is that as + + + align:start position:0% +Titanic one of the dynamics is that as +you revealed information about the stuff + + align:start position:0% +you revealed information about the stuff + + + align:start position:0% +you revealed information about the stuff +that's underneath the foam you start + + align:start position:0% +that's underneath the foam you start + + + align:start position:0% +that's underneath the foam you start +having more decisions to make well what + + align:start position:0% +having more decisions to make well what + + + align:start position:0% +having more decisions to make well what +you know mix that going to be because + + align:start position:0% +you know mix that going to be because + + + align:start position:0% +you know mix that going to be because +you could click on the thing that you + + align:start position:0% +you could click on the thing that you + + + align:start position:0% +you could click on the thing that you +just discovered like if you find us + + align:start position:0% +just discovered like if you find us + + + align:start position:0% +just discovered like if you find us +sending one of the things that that + + align:start position:0% +sending one of the things that that + + + align:start position:0% +sending one of the things that that +people which are my surgeon right now + + align:start position:0% +people which are my surgeon right now + + + align:start position:0% +people which are my surgeon right now +right but then you can also find you + + align:start position:0% +right but then you can also find you + + + align:start position:0% +right but then you can also find you +know a mind and you can assign followers + + align:start position:0% +know a mind and you can assign followers + + + align:start position:0% +know a mind and you can assign followers +into it you could build a road and some + + align:start position:0% +into it you could build a road and some + + + align:start position:0% +into it you could build a road and some +people I think might have noticed what + + align:start position:0% +people I think might have noticed what + + + align:start position:0% +people I think might have noticed what +what roles did + + align:start position:0% +what roles did + + + align:start position:0% +what roles did +thing but yeah your city start actually + + align:start position:0% +thing but yeah your city start actually + + + align:start position:0% +thing but yeah your city start actually +growing a number once you connect them + + align:start position:0% +growing a number once you connect them + + + align:start position:0% +growing a number once you connect them +up a gross error plus that helps with + + align:start position:0% +up a gross error plus that helps with + + + align:start position:0% +up a gross error plus that helps with +defense so so what are the what are the + + align:start position:0% +defense so so what are the what are the + + + align:start position:0% +defense so so what are the what are the +dynamics in this game is that the + + align:start position:0% +dynamics in this game is that the + + + align:start position:0% +dynamics in this game is that the +further that you play in a level the + + align:start position:0% +further that you play in a level the + + + align:start position:0% +further that you play in a level the +board is system all kinds of decisions + + align:start position:0% +board is system all kinds of decisions + + + align:start position:0% +board is system all kinds of decisions +you can make at the beginning of the + + align:start position:0% +you can make at the beginning of the + + + align:start position:0% +you can make at the beginning of the +game you have to make no decisions + + align:start position:0% +game you have to make no decisions + + + align:start position:0% +game you have to make no decisions +decides which one of these things two + + align:start position:0% +decides which one of these things two + + + align:start position:0% +decides which one of these things two +squares am I going to start searching + + align:start position:0% +squares am I going to start searching + + + align:start position:0% +squares am I going to start searching +right up on left you know I think you + + align:start position:0% +right up on left you know I think you + + + align:start position:0% +right up on left you know I think you +always start in one of the corners so + + align:start position:0% +always start in one of the corners so + + + align:start position:0% +always start in one of the corners so +there's only two directions that you + + align:start position:0% +there's only two directions that you + + + align:start position:0% +there's only two directions that you +possibly search what are the dynamics + + align:start position:0% +possibly search what are the dynamics + + + align:start position:0% +possibly search what are the dynamics +are there these are things that arise on + + align:start position:0% +are there these are things that arise on + + + align:start position:0% +are there these are things that arise on +combination of these mechanics okay so + + align:start position:0% +combination of these mechanics okay so + + + align:start position:0% +combination of these mechanics okay so +what are the things is you you set up + + align:start position:0% +what are the things is you you set up + + + align:start position:0% +what are the things is you you set up +initial conditions for hopefully these + + align:start position:0% +initial conditions for hopefully these + + + align:start position:0% +initial conditions for hopefully these +things to work out the circle there's + + align:start position:0% +things to work out the circle there's + + + align:start position:0% +things to work out the circle there's +the system to emerge it in the behavior + + align:start position:0% +the system to emerge it in the behavior + + + align:start position:0% +the system to emerge it in the behavior +right okay what else that's then the + + align:start position:0% +right okay what else that's then the + + + align:start position:0% +right okay what else that's then the +stuff that you set up even before all + + align:start position:0% +stuff that you set up even before all + + + align:start position:0% +stuff that you set up even before all +your trips are over like if you set them + + align:start position:0% +your trips are over like if you set them + + + align:start position:0% +your trips are over like if you set them +people in a bind the - just keep taking + + align:start position:0% +people in a bind the - just keep taking + + + align:start position:0% +people in a bind the - just keep taking +each turn you know it's like you don't + + align:start position:0% +each turn you know it's like you don't + + + align:start position:0% +each turn you know it's like you don't +have to babysit them they'll do they'll + + align:start position:0% +have to babysit them they'll do they'll + + + align:start position:0% +have to babysit them they'll do they'll +keep digging it'll find stuff you know + + align:start position:0% +keep digging it'll find stuff you know + + + align:start position:0% +keep digging it'll find stuff you know +without you telling them to do anything + + align:start position:0% + + + + align:start position:0% + +what else what what what else spits this + + align:start position:0% +what else what what what else spits this + + + align:start position:0% +what else what what what else spits this +kind of description of a something that + + align:start position:0% +kind of description of a something that + + + align:start position:0% +kind of description of a something that +arises still kind of mechanically uh out + + align:start position:0% +arises still kind of mechanically uh out + + + align:start position:0% +arises still kind of mechanically uh out +of all out of a combination of all of + + align:start position:0% +of all out of a combination of all of + + + align:start position:0% +of all out of a combination of all of +these Dietetics + + align:start position:0% + + + + align:start position:0% + +let's take combat for instance when the + + align:start position:0% +let's take combat for instance when the + + + align:start position:0% +let's take combat for instance when the +red forces and your blue forces start + + align:start position:0% +red forces and your blue forces start + + + align:start position:0% +red forces and your blue forces start +you know like no ants stop facing off + + align:start position:0% +you know like no ants stop facing off + + + align:start position:0% +you know like no ants stop facing off +against each other what happens this + + align:start position:0% +against each other what happens this + + + align:start position:0% +against each other what happens this +squashed right okay so so it has + + align:start position:0% +squashed right okay so so it has + + + align:start position:0% +squashed right okay so so it has +interesting curve on like a successful + + align:start position:0% +interesting curve on like a successful + + + align:start position:0% +interesting curve on like a successful +defense like the barbarians are usually + + align:start position:0% +defense like the barbarians are usually + + + align:start position:0% +defense like the barbarians are usually +here and the followers you know usually + + align:start position:0% +here and the followers you know usually + + + align:start position:0% +here and the followers you know usually +on the slightly lower number because + + align:start position:0% +on the slightly lower number because + + + align:start position:0% +on the slightly lower number because +this huge upper barbarians they show up + + align:start position:0% +this huge upper barbarians they show up + + + align:start position:0% +this huge upper barbarians they show up +obviously off huh yeah but but often + + align:start position:0% +obviously off huh yeah but but often + + + align:start position:0% +obviously off huh yeah but but often +what happens is that you've got a number + + align:start position:0% +what happens is that you've got a number + + + align:start position:0% +what happens is that you've got a number +like that and it kind of goes like like + + align:start position:0% +like that and it kind of goes like like + + + align:start position:0% +like that and it kind of goes like like +that right your response off kind of + + align:start position:0% +that right your response off kind of + + + align:start position:0% +that right your response off kind of +like a you know the barbarians still + + align:start position:0% +like a you know the barbarians still + + + align:start position:0% +like a you know the barbarians still +maintained your numbers in all sudden + + align:start position:0% +maintained your numbers in all sudden + + + align:start position:0% +maintained your numbers in all sudden +just collapses this is what a successful + + align:start position:0% +just collapses this is what a successful + + + align:start position:0% +just collapses this is what a successful +defense at that yeah yeah kill me yeah + + align:start position:0% +defense at that yeah yeah kill me yeah + + + align:start position:0% +defense at that yeah yeah kill me yeah +yeah that's that would be what it took + + align:start position:0% +yeah that's that would be what it took + + + align:start position:0% +yeah that's that would be what it took +this will be Facebook yeah I mean that + + align:start position:0% +this will be Facebook yeah I mean that + + + align:start position:0% +this will be Facebook yeah I mean that +that will look more like like like that + + align:start position:0% +that will look more like like like that + + + align:start position:0% +that will look more like like like that +attendants like oh right so this is all + + align:start position:0% +attendants like oh right so this is all + + + align:start position:0% +attendants like oh right so this is all +arising out of the gate mechanics right + + align:start position:0% +arising out of the gate mechanics right + + + align:start position:0% +arising out of the gate mechanics right +this is still this is not a this is not + + align:start position:0% +this is still this is not a this is not + + + align:start position:0% +this is still this is not a this is not +an aesthetic experience all by itself + + align:start position:0% +an aesthetic experience all by itself + + + align:start position:0% +an aesthetic experience all by itself +this is just how the numbers if you plot + + align:start position:0% +this is just how the numbers if you plot + + + align:start position:0% +this is just how the numbers if you plot +it by a fraction of a second by a + + align:start position:0% +it by a fraction of a second by a + + + align:start position:0% +it by a fraction of a second by a +fraction of a second you get a graph + + align:start position:0% +fraction of a second you get a graph + + + align:start position:0% +fraction of a second you get a graph +like this this is just the outdoors and + + align:start position:0% +like this this is just the outdoors and + + + align:start position:0% +like this this is just the outdoors and +doing its thing + + align:start position:0% +doing its thing + + + align:start position:0% +doing its thing +all right what is what did this kind of + + align:start position:0% +all right what is what did this kind of + + + align:start position:0% +all right what is what did this kind of +is that I couldn't go go back to like a + + align:start position:0% +is that I couldn't go go back to like a + + + align:start position:0% +is that I couldn't go go back to like a +successful defense + + align:start position:0% +successful defense + + + align:start position:0% +successful defense +so these writers are not the mechanics + + align:start position:0% +so these writers are not the mechanics + + + align:start position:0% +so these writers are not the mechanics +of the game + + align:start position:0% +of the game + + + align:start position:0% +of the game +you know everything that you know in the + + align:start position:0% +you know everything that you know in the + + + align:start position:0% +you know everything that you know in the +game - if I get thought get followers + + align:start position:0% +game - if I get thought get followers + + + align:start position:0% +game - if I get thought get followers +into a city give them technologies + + align:start position:0% +into a city give them technologies + + + align:start position:0% +into a city give them technologies +buying stuff you know such cities you + + align:start position:0% +buying stuff you know such cities you + + + align:start position:0% +buying stuff you know such cities you +know make sure that I enough followers + + align:start position:0% +know make sure that I enough followers + + + align:start position:0% +know make sure that I enough followers +by connecting the cities up with rural + + align:start position:0% +by connecting the cities up with rural + + + align:start position:0% +by connecting the cities up with rural +it's the other thing that rules allow + + align:start position:0% +it's the other thing that rules allow + + + align:start position:0% +it's the other thing that rules allow +you to do is we distribute followers + + align:start position:0% +you to do is we distribute followers + + + align:start position:0% +you to do is we distribute followers +between cities that I've been connected + + align:start position:0% +between cities that I've been connected + + + align:start position:0% +between cities that I've been connected +that's the thing that you get to do in + + align:start position:0% +that's the thing that you get to do in + + + align:start position:0% +that's the thing that you get to do in +those last ten seconds is that you don't + + align:start position:0% +those last ten seconds is that you don't + + + align:start position:0% +those last ten seconds is that you don't +just assign everybody that you've got + + align:start position:0% +just assign everybody that you've got + + + align:start position:0% +just assign everybody that you've got +you think all the people go into this + + align:start position:0% +you think all the people go into this + + + align:start position:0% +you think all the people go into this +one city you can actually do that you + + align:start position:0% +one city you can actually do that you + + + align:start position:0% +one city you can actually do that you +connect them up with roads + + align:start position:0% +connect them up with roads + + + align:start position:0% +connect them up with roads +ten seconds to do that so everything + + align:start position:0% +ten seconds to do that so everything + + + align:start position:0% +ten seconds to do that so everything +leads up to how many followers you've + + align:start position:0% +leads up to how many followers you've + + + align:start position:0% +leads up to how many followers you've +got it a city that a barbarians about + + align:start position:0% +got it a city that a barbarians about + + + align:start position:0% +got it a city that a barbarians about +that back the barbarians are gonna + + align:start position:0% +that back the barbarians are gonna + + + align:start position:0% +that back the barbarians are gonna +attack right you know this is good this + + align:start position:0% +attack right you know this is good this + + + align:start position:0% +attack right you know this is good this +interaction that keeps going on into all + + align:start position:0% +interaction that keeps going on into all + + + align:start position:0% +interaction that keeps going on into all +barbarians are destroyed then you get + + align:start position:0% +barbarians are destroyed then you get + + + align:start position:0% +barbarians are destroyed then you get +this curve and what sort of a static + + align:start position:0% +this curve and what sort of a static + + + align:start position:0% +this curve and what sort of a static +does it generate but what is the player + + align:start position:0% +does it generate but what is the player + + + align:start position:0% +does it generate but what is the player +hopefully experience because of that + + align:start position:0% + + + + align:start position:0% + +yeah and then and then when they pull + + align:start position:0% +yeah and then and then when they pull + + + align:start position:0% +yeah and then and then when they pull +out of it because it was like yeah it's + + align:start position:0% +out of it because it was like yeah it's + + + align:start position:0% +out of it because it was like yeah it's +like at this point I says oh no we're + + align:start position:0% +like at this point I says oh no we're + + + align:start position:0% +like at this point I says oh no we're +both kind of in the same trajectory yeah + + align:start position:0% +both kind of in the same trajectory yeah + + + align:start position:0% +both kind of in the same trajectory yeah +sure they're dropping but we're dropping + + align:start position:0% +sure they're dropping but we're dropping + + + align:start position:0% +sure they're dropping but we're dropping +too and it's not no it's a girl so well + + align:start position:0% +too and it's not no it's a girl so well + + + align:start position:0% +too and it's not no it's a girl so well +they off suddenly your your hopes come + + align:start position:0% +they off suddenly your your hopes come + + + align:start position:0% +they off suddenly your your hopes come +true + + align:start position:0% +true + + + align:start position:0% +true +right you know and we were cheering we + + align:start position:0% +right you know and we were cheering we + + + align:start position:0% +right you know and we were cheering we +were shouting a heads up as if our + + align:start position:0% +were shouting a heads up as if our + + + align:start position:0% +were shouting a heads up as if our +cheers had any influence on a not quite + + align:start position:0% +cheers had any influence on a not quite + + + align:start position:0% +cheers had any influence on a not quite +sure what to it is how to describe that + + align:start position:0% +sure what to it is how to describe that + + + align:start position:0% +sure what to it is how to describe that +aesthetic but that's the players that's + + align:start position:0% +aesthetic but that's the players that's + + + align:start position:0% +aesthetic but that's the players that's +what the player takes away from this + + align:start position:0% +what the player takes away from this + + + align:start position:0% +what the player takes away from this +game right there's this tiny little + + align:start position:0% +game right there's this tiny little + + + align:start position:0% +game right there's this tiny little +moment of the game it's actually very + + align:start position:0% +moment of the game it's actually very + + + align:start position:0% +moment of the game it's actually very +finely tuned to generate exactly that + + align:start position:0% +finely tuned to generate exactly that + + + align:start position:0% +finely tuned to generate exactly that +experience off the you're not quite sure + + align:start position:0% +experience off the you're not quite sure + + + align:start position:0% +experience off the you're not quite sure +what the outcome of this battle is going + + align:start position:0% +what the outcome of this battle is going + + + align:start position:0% +what the outcome of this battle is going +to be unless you play the game like for + + align:start position:0% +to be unless you play the game like for + + + align:start position:0% +to be unless you play the game like for +hours and hours and hours and then you + + align:start position:0% +hours and hours and hours and then you + + + align:start position:0% +hours and hours and hours and then you +can kind of predict what's going to + + align:start position:0% +can kind of predict what's going to + + + align:start position:0% +can kind of predict what's going to +happen the moment the battle starts + + align:start position:0% +happen the moment the battle starts + + + align:start position:0% +happen the moment the battle starts +because you already know what each + + align:start position:0% +because you already know what each + + + align:start position:0% +because you already know what each +technology actually does but at this + + align:start position:0% +technology actually does but at this + + + align:start position:0% +technology actually does but at this +point of time what you're still learning + + align:start position:0% +point of time what you're still learning + + + align:start position:0% +point of time what you're still learning +the game you don't know why you + + align:start position:0% +the game you don't know why you + + + align:start position:0% +the game you don't know why you +technology does you don't know how the + + align:start position:0% +technology does you don't know how the + + + align:start position:0% +technology does you don't know how the +battles are done it turned out it gets + + align:start position:0% +battles are done it turned out it gets + + + align:start position:0% +battles are done it turned out it gets +really really excited so maybe it + + align:start position:0% +really really excited so maybe it + + + align:start position:0% +really really excited so maybe it +doesn't kind of like that the what matt + + align:start position:0% +doesn't kind of like that the what matt + + + align:start position:0% +doesn't kind of like that the what matt +LeBlanc the designer of this game + + align:start position:0% +LeBlanc the designer of this game + + + align:start position:0% +LeBlanc the designer of this game +describes it was dramatic tension I'm + + align:start position:0% +describes it was dramatic tension I'm + + + align:start position:0% +describes it was dramatic tension I'm +not quite sure he's using that term like + + align:start position:0% +not quite sure he's using that term like + + + align:start position:0% +not quite sure he's using that term like +exactly the way how it will be used in + + align:start position:0% +exactly the way how it will be used in + + + align:start position:0% +exactly the way how it will be used in +literary convention but but it is whew + + align:start position:0% +literary convention but but it is whew + + + align:start position:0% +literary convention but but it is whew +it does feel tense because this is out + + align:start position:0% +it does feel tense because this is out + + + align:start position:0% +it does feel tense because this is out +this is uncertain outcome about who's + + align:start position:0% +this is uncertain outcome about who's + + + align:start position:0% +this is uncertain outcome about who's +going to come out ahead and then when it + + align:start position:0% +going to come out ahead and then when it + + + align:start position:0% +going to come out ahead and then when it +resolves in your favor you feel great + + align:start position:0% +resolves in your favor you feel great + + + align:start position:0% +resolves in your favor you feel great +that's basically one dissection using + + align:start position:0% +that's basically one dissection using + + + align:start position:0% +that's basically one dissection using +the MDA framework that we just went + + align:start position:0% +the MDA framework that we just went + + + align:start position:0% +the MDA framework that we just went +through there's a whole bunch of + + align:start position:0% +through there's a whole bunch of + + + align:start position:0% +through there's a whole bunch of +mechanics create a dynamic they creates + + align:start position:0% +mechanics create a dynamic they creates + + + align:start position:0% +mechanics create a dynamic they creates +this a static experience which is the + + align:start position:0% +this a static experience which is the + + + align:start position:0% +this a static experience which is the +thing that you want your players to have + + align:start position:0% +thing that you want your players to have + + + align:start position:0% +thing that you want your players to have +in this particular case this was + + align:start position:0% +in this particular case this was + + + align:start position:0% +in this particular case this was +explicitly what Matt LeBlanc wanted his + + align:start position:0% +explicitly what Matt LeBlanc wanted his + + + align:start position:0% +explicitly what Matt LeBlanc wanted his +players to experience he wanted them to + + align:start position:0% +players to experience he wanted them to + + + align:start position:0% +players to experience he wanted them to +cheer for the followers even though that + + align:start position:0% +cheer for the followers even though that + + + align:start position:0% +cheer for the followers even though that +has no impact on the final result of the + + align:start position:0% +has no impact on the final result of the + + + align:start position:0% +has no impact on the final result of the +fight so when you look at your games I + + align:start position:0% +fight so when you look at your games I + + + align:start position:0% +fight so when you look at your games I +want you to be asking your play testers + + align:start position:0% +want you to be asking your play testers + + + align:start position:0% +want you to be asking your play testers +what they are feeling about the game + + align:start position:0% +what they are feeling about the game + + + align:start position:0% +what they are feeling about the game +usually after they're done you know it's + + align:start position:0% +usually after they're done you know it's + + + align:start position:0% +usually after they're done you know it's +like how do you feel about that + + align:start position:0% + + + + align:start position:0% + +you know what did you like about the + + align:start position:0% +you know what did you like about the + + + align:start position:0% +you know what did you like about the +game what didn't you like about the game + + align:start position:0% +game what didn't you like about the game + + + align:start position:0% +game what didn't you like about the game +both both are aesthetic experiences that + + align:start position:0% +both both are aesthetic experiences that + + + align:start position:0% +both both are aesthetic experiences that +come out from the play of the game this + + align:start position:0% +come out from the play of the game this + + + align:start position:0% +come out from the play of the game this +is much easier to do with people who are + + align:start position:0% +is much easier to do with people who are + + + align:start position:0% +is much easier to do with people who are +actually not in this class because + + align:start position:0% +actually not in this class because + + + align:start position:0% +actually not in this class because +you're all thinking about the games or + + align:start position:0% +you're all thinking about the games or + + + align:start position:0% +you're all thinking about the games or +the rules level if you go to somebody to + + align:start position:0% +the rules level if you go to somebody to + + + align:start position:0% +the rules level if you go to somebody to +plays games but doesn't really make + + align:start position:0% +plays games but doesn't really make + + + align:start position:0% +plays games but doesn't really make +games or is it in the process of + + align:start position:0% +games or is it in the process of + + + align:start position:0% +games or is it in the process of +learning about how to make games it's a + + align:start position:0% +learning about how to make games it's a + + + align:start position:0% +learning about how to make games it's a +lot easier for them to just think about + + align:start position:0% +lot easier for them to just think about + + + align:start position:0% +lot easier for them to just think about +well I kind of felt crappy because I + + align:start position:0% +well I kind of felt crappy because I + + + align:start position:0% +well I kind of felt crappy because I +didn't feel that was any way for me to + + align:start position:0% +didn't feel that was any way for me to + + + align:start position:0% +didn't feel that was any way for me to +come back in this game you know oh yeah + + align:start position:0% +come back in this game you know oh yeah + + + align:start position:0% +come back in this game you know oh yeah +I felt like you know I would ruffle + + align:start position:0% +I felt like you know I would ruffle + + + align:start position:0% +I felt like you know I would ruffle +stomping everybody ruffle stop based on + + align:start position:0% +stomping everybody ruffle stop based on + + + align:start position:0% +stomping everybody ruffle stop based on +aesthetic + + align:start position:0% +aesthetic + + + align:start position:0% +aesthetic +you know those those are things that you + + align:start position:0% +you know those those are things that you + + + align:start position:0% +you know those those are things that you +can sort of take you can sort of take + + align:start position:0% +can sort of take you can sort of take + + + align:start position:0% +can sort of take you can sort of take +acid game designers give you clues on + + align:start position:0% +acid game designers give you clues on + + + align:start position:0% +acid game designers give you clues on +whether your game is doing what you + + align:start position:0% +whether your game is doing what you + + + align:start position:0% +whether your game is doing what you +wanted to do from the mechanics that + + align:start position:0% +wanted to do from the mechanics that + + + align:start position:0% +wanted to do from the mechanics that +you're designing whether the game is not + + align:start position:0% +you're designing whether the game is not + + + align:start position:0% +you're designing whether the game is not +doing what you wanted to do because + + align:start position:0% +doing what you wanted to do because + + + align:start position:0% +doing what you wanted to do because +maybe the mechanics are interacting in a + + align:start position:0% +maybe the mechanics are interacting in a + + + align:start position:0% +maybe the mechanics are interacting in a +way that creates a dynamic that you + + align:start position:0% +way that creates a dynamic that you + + + align:start position:0% +way that creates a dynamic that you +didn't want or maybe the game is doing + + align:start position:0% +didn't want or maybe the game is doing + + + align:start position:0% +didn't want or maybe the game is doing +not what you wanted to do and it's + + align:start position:0% +not what you wanted to do and it's + + + align:start position:0% +not what you wanted to do and it's +actually pretty cool there's always the + + align:start position:0% +actually pretty cool there's always the + + + align:start position:0% +actually pretty cool there's always the +accidental discovery of your mechanics + + align:start position:0% +accidental discovery of your mechanics + + + align:start position:0% +accidental discovery of your mechanics +doing something that you didn't quite + + align:start position:0% +doing something that you didn't quite + + + align:start position:0% +doing something that you didn't quite +expect you know maybe you expected + + align:start position:0% +expect you know maybe you expected + + + align:start position:0% +expect you know maybe you expected +something to be kind of like like cool + + align:start position:0% +something to be kind of like like cool + + + align:start position:0% +something to be kind of like like cool +and strategic and detached but then your + + align:start position:0% +and strategic and detached but then your + + + align:start position:0% +and strategic and detached but then your +players end up feeling very really + + align:start position:0% +players end up feeling very really + + + align:start position:0% +players end up feeling very really +tensed and and feeling that everything's + + align:start position:0% +tensed and and feeling that everything's + + + align:start position:0% +tensed and and feeling that everything's +on the line and everything could go + + align:start position:0% +on the line and everything could go + + + align:start position:0% +on the line and everything could go +wrong and every ball and any moment I + + align:start position:0% +wrong and every ball and any moment I + + + align:start position:0% +wrong and every ball and any moment I +didn't like that then okay all right you + + align:start position:0% +didn't like that then okay all right you + + + align:start position:0% +didn't like that then okay all right you +know that's that's something you can + + align:start position:0% +know that's that's something you can + + + align:start position:0% +know that's that's something you can +work with but you may not necessarily + + align:start position:0% +work with but you may not necessarily + + + align:start position:0% +work with but you may not necessarily +understand that's what your game is + + align:start position:0% +understand that's what your game is + + + align:start position:0% +understand that's what your game is +doing if you're not asking your players + + align:start position:0% +doing if you're not asking your players + + + align:start position:0% +doing if you're not asking your players +what's the sensation in to getting out + + align:start position:0% +what's the sensation in to getting out + + + align:start position:0% +what's the sensation in to getting out +of the game purely from the rules when + + align:start position:0% +of the game purely from the rules when + + + align:start position:0% +of the game purely from the rules when +you're working with the prototypes in + + align:start position:0% +you're working with the prototypes in + + + align:start position:0% +you're working with the prototypes in +particular it's very easy for them for + + align:start position:0% +particular it's very easy for them for + + + align:start position:0% +particular it's very easy for them for +you to make this connection back your + + align:start position:0% +you to make this connection back your + + + align:start position:0% +you to make this connection back your +mechanics because they can't be + + align:start position:0% +mechanics because they can't be + + + align:start position:0% +mechanics because they can't be +experiencing terribly much from your + + align:start position:0% +experiencing terribly much from your + + + align:start position:0% +experiencing terribly much from your +artwork or for their sound effects right + + align:start position:0% +artwork or for their sound effects right + + + align:start position:0% +artwork or for their sound effects right +you know unless it make you sound + + align:start position:0% +you know unless it make you sound + + + align:start position:0% +you know unless it make you sound +effects with your mouth or something it + + align:start position:0% +effects with your mouth or something it + + + align:start position:0% +effects with your mouth or something it +probably sounds pretty goofy but you + + align:start position:0% +probably sounds pretty goofy but you + + + align:start position:0% +probably sounds pretty goofy but you +know they can only really sort of get an + + align:start position:0% +know they can only really sort of get an + + + align:start position:0% +know they can only really sort of get an +aesthetic experience out of your rules + + align:start position:0% +aesthetic experience out of your rules + + + align:start position:0% +aesthetic experience out of your rules +obviously this is not the only way that + + align:start position:0% +obviously this is not the only way that + + + align:start position:0% +obviously this is not the only way that +you can convey an aesthetic experience + + align:start position:0% +you can convey an aesthetic experience + + + align:start position:0% +you can convey an aesthetic experience +you can + + align:start position:0% +you can + + + align:start position:0% +you can +things from art sound storytelling + + align:start position:0% +things from art sound storytelling + + + align:start position:0% +things from art sound storytelling +characters plot and everything we'll go + + align:start position:0% +characters plot and everything we'll go + + + align:start position:0% +characters plot and everything we'll go +into that a little bit more before + + align:start position:0% +into that a little bit more before + + + align:start position:0% +into that a little bit more before +assignment 2 because you're going to be + + align:start position:0% +assignment 2 because you're going to be + + + align:start position:0% +assignment 2 because you're going to be +exploring that wave assignment too but + + align:start position:0% +exploring that wave assignment too but + + + align:start position:0% +exploring that wave assignment too but +this is one particular kind of aesthetic + + align:start position:0% +this is one particular kind of aesthetic + + + align:start position:0% +this is one particular kind of aesthetic +that which I will refer to it in clay in + + align:start position:0% +that which I will refer to it in clay in + + + align:start position:0% +that which I will refer to it in clay in +this class as system aesthetics the + + align:start position:0% +this class as system aesthetics the + + + align:start position:0% +this class as system aesthetics the +aesthetics that come out from the system + + align:start position:0% +aesthetics that come out from the system + + + align:start position:0% +aesthetics that come out from the system +of all of your mechanics working + + align:start position:0% +of all of your mechanics working + + + align:start position:0% +of all of your mechanics working +together and in this project this first + + align:start position:0% +together and in this project this first + + + align:start position:0% +together and in this project this first +assignment you don't have to worry about + + align:start position:0% +assignment you don't have to worry about + + + align:start position:0% +assignment you don't have to worry about +hitting the design aesthetic you don't + + align:start position:0% +hitting the design aesthetic you don't + + + align:start position:0% +hitting the design aesthetic you don't +really have to that's not the goal of + + align:start position:0% +really have to that's not the goal of + + + align:start position:0% +really have to that's not the goal of +this project I want you to figure out + + align:start position:0% +this project I want you to figure out + + + align:start position:0% +this project I want you to figure out +everything that y'all gave McKenna can + + align:start position:0% +everything that y'all gave McKenna can + + + align:start position:0% +everything that y'all gave McKenna can +do and by the way there was a question + + align:start position:0% +do and by the way there was a question + + + align:start position:0% +do and by the way there was a question +be at the beginning of class what if we + + align:start position:0% +be at the beginning of class what if we + + + align:start position:0% +be at the beginning of class what if we +wanted to change that by coming because + + align:start position:0% +wanted to change that by coming because + + + align:start position:0% +wanted to change that by coming because +you discovered something along the way + + align:start position:0% +you discovered something along the way + + + align:start position:0% +you discovered something along the way +that's fine but whatever you change it + + align:start position:0% +that's fine but whatever you change it + + + align:start position:0% +that's fine but whatever you change it +to make sure that you're going deep into + + align:start position:0% +to make sure that you're going deep into + + + align:start position:0% +to make sure that you're going deep into +that thing make sure that you're not + + align:start position:0% +that thing make sure that you're not + + + align:start position:0% +that thing make sure that you're not +just like running with what you stumbled + + align:start position:0% +just like running with what you stumbled + + + align:start position:0% +just like running with what you stumbled +with this and then not developing it any + + align:start position:0% +with this and then not developing it any + + + align:start position:0% +with this and then not developing it any +further + + align:start position:0% +further + + + align:start position:0% +further +try to really really explore what what + + align:start position:0% +try to really really explore what what + + + align:start position:0% +try to really really explore what what +you eventually will declare that you're + + align:start position:0% +you eventually will declare that you're + + + align:start position:0% +you eventually will declare that you're +looking at the reason for that is that I + + align:start position:0% +looking at the reason for that is that I + + + align:start position:0% +looking at the reason for that is that I +want you all to have like the experience + + align:start position:0% +want you all to have like the experience + + + align:start position:0% +want you all to have like the experience +of going really deep into mechanics and + + align:start position:0% +of going really deep into mechanics and + + + align:start position:0% +of going really deep into mechanics and +figuring out all the different things + + align:start position:0% +figuring out all the different things + + + align:start position:0% +figuring out all the different things +that one mechanic can do so that later + + align:start position:0% +that one mechanic can do so that later + + + align:start position:0% +that one mechanic can do so that later +on when you all mix and match and form + + align:start position:0% +on when you all mix and match and form + + + align:start position:0% +on when you all mix and match and form +them into assignment 2 and assignment 3 + + align:start position:0% +them into assignment 2 and assignment 3 + + + align:start position:0% +them into assignment 2 and assignment 3 +teams you've got like a pool of + + align:start position:0% +teams you've got like a pool of + + + align:start position:0% +teams you've got like a pool of +knowledge and more importantly a pool of + + align:start position:0% +knowledge and more importantly a pool of + + + align:start position:0% +knowledge and more importantly a pool of +experience and sort of exploring what a + + align:start position:0% +experience and sort of exploring what a + + + align:start position:0% +experience and sort of exploring what a +mechanic can do so that you can take on + + align:start position:0% +mechanic can do so that you can take on + + + align:start position:0% +mechanic can do so that you can take on +new mechanics you can share information + + align:start position:0% +new mechanics you can share information + + + align:start position:0% +new mechanics you can share information +with each other and use that later to + + align:start position:0% +with each other and use that later to + + + align:start position:0% +with each other and use that later to +generate interesting and starting + + align:start position:0% +generate interesting and starting + + + align:start position:0% +generate interesting and starting +experiences I said yeah and this is what + + align:start position:0% +experiences I said yeah and this is what + + + align:start position:0% +experiences I said yeah and this is what +the players are here for they don't care + + align:start position:0% +the players are here for they don't care + + + align:start position:0% +the players are here for they don't care +about the amount of work that you put + + align:start position:0% +about the amount of work that you put + + + align:start position:0% +about the amount of work that you put +into here they only care about whether + + align:start position:0% +into here they only care about whether + + + align:start position:0% +into here they only care about whether +the game makes them feel the way they + + align:start position:0% +the game makes them feel the way they + + + align:start position:0% +the game makes them feel the way they +didn't want to feel right now for a + + align:start position:0% +didn't want to feel right now for a + + + align:start position:0% +didn't want to feel right now for a +while they're playing joking so any + + align:start position:0% +while they're playing joking so any + + + align:start position:0% +while they're playing joking so any +questions + + align:start position:0% + + + + align:start position:0% + +well we'll probably go a little bit more + + align:start position:0% +well we'll probably go a little bit more + + + align:start position:0% +well we'll probably go a little bit more +into things about mechanics later this + + align:start position:0% +into things about mechanics later this + + + align:start position:0% +into things about mechanics later this +this month but right now the rest of the + + align:start position:0% +this month but right now the rest of the + + + align:start position:0% +this month but right now the rest of the +class is actually time for you to work + + align:start position:0% +class is actually time for you to work + + + align:start position:0% +class is actually time for you to work +as a team some of you probably haven't + + align:start position:0% +as a team some of you probably haven't + + + align:start position:0% +as a team some of you probably haven't +seen each other since Wednesday and may + + align:start position:0% +seen each other since Wednesday and may + + + align:start position:0% +seen each other since Wednesday and may +not necessarily even have talked to each + + align:start position:0% +not necessarily even have talked to each + + + align:start position:0% +not necessarily even have talked to each +other so that's fine take time now if + + align:start position:0% +other so that's fine take time now if + + + align:start position:0% +other so that's fine take time now if +you then you've got something that you + + align:start position:0% +you then you've got something that you + + + align:start position:0% +you then you've got something that you +need test it you have two options one + + align:start position:0% +need test it you have two options one + + + align:start position:0% +need test it you have two options one +you can grab Rick and I or two you can + + align:start position:0% +you can grab Rick and I or two you can + + + align:start position:0% +you can grab Rick and I or two you can +Rick so you can grab other people in the + + align:start position:0% +Rick so you can grab other people in the + + + align:start position:0% +Rick so you can grab other people in the +classroom who don't necessarily have + + align:start position:0% +classroom who don't necessarily have + + + align:start position:0% +classroom who don't necessarily have +played a game I would suggest asking + + align:start position:0% +played a game I would suggest asking + + + align:start position:0% +played a game I would suggest asking +people who haven't played your game + + align:start position:0% +people who haven't played your game + + + align:start position:0% +people who haven't played your game +before for two tests tomorrow is + + align:start position:0% +before for two tests tomorrow is + + + align:start position:0% +before for two tests tomorrow is +actually the formal play test so what + + align:start position:0% +actually the formal play test so what + + + align:start position:0% +actually the formal play test so what +you absolutely have to have by the end + + align:start position:0% +you absolutely have to have by the end + + + align:start position:0% +you absolutely have to have by the end +of this class all right all right or by + + align:start position:0% +of this class all right all right or by + + + align:start position:0% +of this class all right all right or by +the what you have to have by the + + align:start position:0% +the what you have to have by the + + + align:start position:0% +the what you have to have by the +beginning of tomorrow to twelve to us is + + align:start position:0% +beginning of tomorrow to twelve to us is + + + align:start position:0% +beginning of tomorrow to twelve to us is +something that you'll be played at + + align:start position:0% +something that you'll be played at + + + align:start position:0% +something that you'll be played at +something class so today that's no + + align:start position:0% +something class so today that's no + + + align:start position:0% +something class so today that's no +required play test tomorrow Darius + + align:start position:0% +required play test tomorrow Darius + + + align:start position:0% +required play test tomorrow Darius +alright and that's also reading for + + align:start position:0% +alright and that's also reading for + + + align:start position:0% +alright and that's also reading for +tomorrow but it's not that bad I think + + align:start position:0% +tomorrow but it's not that bad I think + + + align:start position:0% +tomorrow but it's not that bad I think +it'll be okay and I was doing a partner + + align:start position:0% +it'll be okay and I was doing a partner + + + align:start position:0% +it'll be okay and I was doing a partner +yeah it's going to be just looking at + + align:start position:0% +yeah it's going to be just looking at + + + align:start position:0% +yeah it's going to be just looking at +one thing which is the randomizing and + + align:start position:0% +one thing which is the randomizing and + + + align:start position:0% +one thing which is the randomizing and +if I had a functional dice in games so + + align:start position:0% +if I had a functional dice in games so + + + align:start position:0% +if I had a functional dice in games so +okay what are your tips and all the + + align:start position:0% +okay what are your tips and all the + + + align:start position:0% +okay what are your tips and all the +materials are here we'll put it on the + + align:start position:0% +materials are here we'll put it on the + + + align:start position:0% +materials are here we'll put it on the +table content from the following sources + + align:start position:0% +table content from the following sources + + + align:start position:0% +table content from the following sources +is copyright of the respective holders + + align:start position:0% +is copyright of the respective holders + + + align:start position:0% +is copyright of the respective holders +all rights reserved + + align:start position:0% +all rights reserved + + + align:start position:0% +all rights reserved +excluded from our Creative Commons + + align:start position:0% +excluded from our Creative Commons + + + align:start position:0% +excluded from our Creative Commons +license for more information see + + align:start position:0% +license for more information see + + + align:start position:0% +license for more information see +ocw.mit.edu + + align:start position:0% +ocw.mit.edu + + + align:start position:0% +ocw.mit.edu +slash fair use erases play first 2005 + + align:start position:0% +slash fair use erases play first 2005 + + + align:start position:0% +slash fair use erases play first 2005 +video game \ No newline at end of file diff --git a/H5m39G-FAwE.txt b/H5m39G-FAwE.txt new file mode 100644 index 0000000000000000000000000000000000000000..8cd9ed3221e7fdeb217e8982ae0cb1c5f203731a --- /dev/null +++ b/H5m39G-FAwE.txt @@ -0,0 +1,4741 @@ +The following +content is provided + +under a Creative +Commons license. + +Your support will help MIT +OpenCourseWare continue + +to offer high quality +educational resources for free. + +To make a donation or to +view additional materials + +from hundreds of MIT courses, +visit MIT OpenCourseWare + +at ocw.mit.edu. + +PROFESSOR: All right. + +Hi, everyone. + +AUDIENCE: Hi. + +PROFESSOR: We're getting +towards the end of the semester. + +Things are starting to +cohere and come together. + +We have one more midterm exam. + +So there is an exam +next Thursday, the 18th. + +OK? + +There will be a problem set due. + +It'll be posted later today, +and it will be due next week + +on Tuesday as usual. + +Of course, next week on Tuesday +is a holiday technically, + +so we'll actually make the +due date be on Wednesday. + +So on Wednesday at 10 o'clock. + +You should think +of this problem set + +as part of the +review for the exam. + +Material that is covered +today and on Thursday + +will be fair game for the exam. + +So the format of +the exam is going + +to be much more canonical. + +It's going to be a +series of short answer + +plus a series of computations. + +They'll be, roughly speaking, +at the level of the problem + +sets, and a practice +exam will be + +posted in the next +couple of days. + +The practice exam is going +to be of the same general + +intellectual +difficulty, but it's + +going to be considerably +longer than the actual exam. + +So as a check for yourself +here's what I would recommend. + +I would recommend sitting +down and giving yourself + +an hour and a half or two +hours with the practice exam + +and see how that goes. + +OK? + +Try to give yourself +the time constraint. + +And here's one of the +things that-- there's + +a very strong correlation +between having + +nailed the problem sets, and +worked through all the practice + +exams, and just done +a lot of problems, + +and doing well on exams. + +You'll be more confident. + +The only way to study +for these things is just + +do a lot of problems. + +So on Stellar, for example, +are a bunch of previous problem + +sets, and previous +exams and practice + +exams from previous years. + +I would encourage you to +look at those also on OCW + +and use those as practice. + +OK, any practical +questions before we + +get on to the physics. + +Yeah? + +AUDIENCE: Will the exam +cover all the material, + +or all the material [INAUDIBLE]? + +PROFESSOR: This is +a cumulative topic. + +So the question is does it +cover everything, or just + +last couple of weeks. + +And it's a cumulative topic, +so the entire semester + +is necessary in order +to answer the problems. + +Other questions? + +OK. + +Anything else? + +So quick couple of +review questions + +before we launch into the +main material of today. + +These are going to +turn out to be useful + +reminders later on +in today's lecture. + +So first, suppose +I tell you I have + +a system with energy operator +E, which has an operator A such + +that the commutator of E with +A would say plus h bar A. OK? + +What does that tell you about +the spectrum of the energy + +operator? + +AUDIENCE: It's a ladder. + +PROFESSOR: It's a +ladder, exactly. + +So this tells you that the +spectrum of E, or the energy + +eigenvalues En, +are evenly spaced-- + +and we need a dimensional +constant here, + +omega-- evenly spaced +by h bar omega. + +And more precisely, that +given a state phi E, + +we can act on it +with the operator A + +to give us a new state, which +is also an energy eigenstate, + +with energy E plus h bar omega. + +right? + +So any time you see that +commutation relation, + +you know this fact to be true. + +Second statement. + +Suppose I have an +operator B which + +commutes with the +energy operator. + +OK? + +So that the commutator vanishes. + +What does that tell +you about the system? + +AUDIENCE: Simultaneous +eigenfunctions [INAUDIBLE]. + +PROFESSOR: Excellent. + +So one one consequence +is that there + +exists simultaneous +eigenfunctions phi sub E, B, + +which are simultaneous +eigenfunctions of both E and B. + +What else does it tell you? + +Well, notice the following. + +Notice that if we took this +computation relation and set + +omega to 0, we get this +commutation relation. + +So this commutation relation is +of the form of this commutation + +relation with omega equals 0. + +So what does that tell +you about the states? + +About the energy eigenvalues? + +What happens if I +take a state phi sub E + +and I act on it with B? + +What do I get? + +What can you say +about this function? + +Well, what is its +eigenvalue under E? + +It's E. It's the same +thing, because they commute. + +You can pull the E +through, multiply it, + +you get the constant E, +you pull it back out. + +This is still an +eigenfunction of phi + +of the energy operator +with the same eigenvalue. + +But is it necessarily +the same eigenfunction? + +No, because B may act +on phi and just give you + +a different state. + +So this is some eigenfunction +with the same energy, + +but it may be a +different eigenfunction. + +OK? + +So let's think of +an example of this. + +An example of this is +consider a free particle. + +In the case of a +free particle, we + +have E is equal to +P squared upon 2m. + +And as a consequence +E and P commute. + +Everyone agree with that? + +Everyone happy with +that statement? + +They commute. + +So plus 0 if you will. + +And here what I wanted to say +is when you have an operator + +that commutes with +the energy, then + +there can be multiple states +with the same energy which + +are different states, right? + +Different states entirely. + +So for example, +in this case, what + +are the energy eigenfunctions? + +Well, e to the ikx. + +And this has energy h bar +squared k squared upon 2m. + +But there's another state, which +is a different state, which + +has the same energy. + +e to the minus ikx. + +OK? + +So when you have an operator +that commutes with the energy + +operator, you can have +simultaneous eigenfunctions. + +And you can also have +multiple eigenfunctions + +that have the same +energy eigenvalue, + +but are different functions. + +For example, this. + +Everyone cool with that? + +Now, just to make clear +that it's actually + +the commuting that +matters, imagine + +we took not the free particle, +but the harmonic oscillator. + +E is p squared upon 2m plus m +omega squared upon 2 x squared. + +Is it true that E-- I'll call +this harmonic oscillator-- + +does E harmonic +oscillator commute with P? + +No, you're going to +get a term that's + +m omega squared x +from the commutator. + +The potential is not +translationally invariant. + +It does not commute +with momentum. + +So this is not equal to 0. + +So that suggests that this +degeneracy, two states having + +the same energy, +should not be present. + +And indeed, are the +states degenerate + +for the harmonic oscillator. + +No. + +No degeneracy. + +Yeah? + +AUDIENCE: We did +something [INAUDIBLE] + +where I think it said that the +eigenfunctions were complete. + +PROFESSOR: Yes. + +AUDIENCE: What does that mean? + +PROFESSOR: What does it +mean for the eigenfunctions + +to be complete? + +What that means is +that they form a basis. + +AUDIENCE: So the basis +doesn't necessarily + +mean not [INAUDIBLE]. + +PROFESSOR: Yeah, no one told you +the basis had to be degenerate, + +and in particular, +that's a excellent-- + +so the question here +is, wait a minute, + +I thought a basis had to be +a complete set-- if you had + +an energy operator and you +constructed the energy eigen-- + +this is a very good question. + +Thank you. + +If I have the energy operator +and I construct it's energy + +eigenfunctions, then those +energy eigenfunctions + +form a complete basis for +any arbitrary function. + +Any function can be +expanded in it, right? + +So for example, for +the free particle, + +the energy eigenfunctions +are e to the ikx, + +the momentum eigenfunctions +for any value of k. + +But wait, how can there +be multiple states + +with the same energy? + +Isn't that double +counting or something? + +And the important thing is +those guys have the same energy, + +but they have different momenta. + +They're different states. + +One has momentum h bar k. + +One has momentum minus h bar k. + +And you know that +that has to be true, + +because the Fourier +theorem tells you, + +in order to form a complete +basis, you need all of them, + +all possible values of k. + +So there's no problem with +being a complete basis + +and having states have the +same energy eigenvalue, OK? + +It's a good question. + +Other questions? + +Yeah? + +AUDIENCE: So if we have a +potential that only admits + +bound states, we'll never +have this commutation + +happen basically? + +PROFESSOR: Yeah, exactly. + +Excellent. + +So the observation is this. + +Look, imagine I have a +potential that's not trivial. + +It's not 0, OK? + +Will the momentum commute +with the energy operator. + +No, because it's got +a potential that's + +going to be acted upon by P, so +you'll get a derivative term. + +But more precisely, if I have +a system with bound states, + +I have to have a +potential, right? + +And then I can't have P +commuting with the energy + +operator, which means I +can't have degeneracies. + +So indeed, if you +have bound states, + +you cannot have degeneracies. + +That's exactly right. + +Yeah? + +AUDIENCE: But doesn't this +break down in higher dimensions? + +PROFESSOR: Excellent, +so we're going + +to come back to higher +dimensions later. + +So the question +predicts what's going + +to happen in the +rest of the lecture. + +What we're going to +do in just a minute + +is we're going to +start working in three + +dimensions for the first time. + +We're going to leave 1D behind. + +We're going to take our +tripped out tricycle + +and replace it with a Yamaha. + +As you'll see, it has the +same basic physics driving + +its, well, self. + +It's the same dynamics. + +But I want to emphasize +a couple things that + +are going to show up. + +So the question is, +isn't this story + +different in three dimensions? + +And we shall see exactly what +happens in higher dimensions. + +We'll work in two dimensions. + +We'll work in three dimensions. + +We'll work in more. + +Doesn't really matter how +many dimensions we work in. + +You'll see it. + +OK, third thing. + +You studied this in some +detail in your problem set. + +Suppose I have an +energy operator + +that commutes with a +unitary operator, U, OK? + +So it commutes to 0. + +And U is unitary, so U dagger +U is one, is the identity. + +So what does this tell you? + +Well, first off +from these guys it + +tells us that we can have +simultaneous eigenfunctions. + +It also tells us too that +if we take our state phi + +and we act on it with +U, this could give us + +a new state, phi tilde sub +E, which will necessarily + +have the same energy eigenvalue, +because U and E commute. + +But it may be a different state. + +We'll come to this +in more detail later. + +But the third thing, and +I want to emphasize this, + +is this tells us, look, we +have a unitary operator. + +We can always write the +unitary operator as e + +to the i of a +Hermitian operator. + +So what is the meaning of +the Hermitian operator? + +What is this guy? + +So in your problem +set, you looked + +at what unitary operators are. + +And in the problem set, it's +discussed in some detail + +that there's a +relationship between + +a unitary transformation, +or unitary operator, + +and the symmetry. + +A symmetry is when +you take your system + +and you do something to it, +like a rotation or translation, + +and it's a symmetry if it +doesn't change anything, + +if the energy remains invariant. + +So if the energy doesn't change +under this transformation, + +we call that a symmetry. + +And we also showed that +symmetries, or translations, + +are generated by +unitary operators. + +For example, my favorite +examples are the translate by L + +operator, which is unitary. + +And also e to the minus dxl. + +And the boost by +q operator, which + +similarly is e to the minus qdp. + +And the time translation +operator, U sub t, + +which is equal to e to the minus +i t over h bar energy operator. + +OK? + +So these are +transformation operators. + +These are symmetry operators, +which translate you by L, + +boost or speed you +up by momentum q, + +evolve you forward in time t. + +And they can all be expressed +as e to the unitary operator. + +So this in particular +is l i over h bar p. + +And this is similarly x. + +And earlier we understood +the role of momentum + +having to do translations +in the following way. + +There's a beautiful +theorem about this. + +If you take a system and +its translation invariant, + +the classical statement +of Noether's theorem + +is that there's a conserved +quantity associated + +with that translation. + +That conserved quantity +is the momentum. + +And quantum mechanically, +the generator + +of that transformation +the Hermitian operator + +that goes upstairs +in the unitary + +is the operator associated +to that conserved quantity, + +associated to that observable. + +You have translations. + +There's a conserved +quantity, which is momentum. + +And the thing that generates +translations, the operator that + +generates translations, is the +operator representing momentum. + +So each of these are going +to come up later in today, + +and I just wanted to flag +them down before the moment. + +OK, questions before we move on? + +Yeah? + +AUDIENCE: So you made the claim +that every unitary operator can + +be expressed as p to +the eigenfunction. + +PROFESSOR: OK, I should be a +little bit careful, but yes. + +That's right. + +AUDIENCE: But if I +take the [INAUDIBLE] I + +should be able to +figure out what it is, + +but you can't take +the [INAUDIBLE] + +PROFESSOR: The more +precise statement + +is that any unitary-- +any one parameter + +family of unitary operators +can be expressed in that form. + +And then you can +take a derivative. + +And that's the theory +of [INAUDIBLE], + +which is beyond the scope. + +Let me make a very +specific statement, which + +is that one parameter +of [INAUDIBLE] + +unitary transformation. + +So translations by l, +where you can vary l, + +can be expressed in that form. + +And that's a very +general statement. + +OK, so with all that as +prelude, let's go back to 3D. + +So in 3D, the energy operator-- +so what's going to change? + +Now instead of just having +position and its momentum, + +we now also have-- I'll call +this P sub x-- we can also + +have a y-coordinate and +we have a z-coordinate. + +And each of them +has its momentum. + +P sub z and P sub y. + +And here's just a quick +practical question. + +We know that x with Px +is equal to i h bar. + +So what do you expect +to be true of x with y? + +AUDIENCE: 0. + +PROFESSOR: Why? + +AUDIENCE: [INAUDIBLE]. + +PROFESSOR: What does +this equation tell you? + +What is its physical content? + +Well, that they +don't commute, good. + +What does that tell +you physically? + +Yes? + +AUDIENCE: That there's +an uncertainty principle + +connecting the two. + +PROFESSOR: Excellent. + +So that's one statement. + +So the consequence of +this is that there's + +an uncertainty principle. + +Delta x delta Px must be greater +than or equal to h bar upon 2. + +What's another way +of saying this? + +Do there exist simultaneous +eigenfunctions of x and P? + +AUDIENCE: No. + +PROFESSOR: No. + +No simultaneous eigenfunctions. + +OK, so you can't +have a definite value + +of x and a definite value +of P simultaneously. + +There's no such state. + +It's not that you can't know. + +It's that there's no such state. + +Do you expect to be able +to know the position in x + +and the position in +y simultaneously? + +Sure. + +OK, so this turns out to be 0. + +And in some sense, +you can take that + +as a definition of +quantum mechanics. + +x and y need to be 0. + +And similarly, Px +and Py commute. + +The momenta are independent. + +However, Py and y should +be equal to minus i h bar. + +Good. + +Exactly. + +So the commutators +work out exactly + +as you'd naively expect. + +Every pair of position and its +momenta commute canonically + +to i h bar. + +And every pair of +coordinates commute to 0. + +Every pair of +momenta commute to 0. + +Cool? + +So what kind of systems are +we going to interested in? + +Well, we're going to be +interested in systems + +where the energy +operator is equal to P + +vector hat squared upon 2m plus +U of x and y and z, hat, hat. + +You can see why dropping +the hats becomes almost / + +So in this language, we can +write the Schrodinger equation. + +This is just a direct extension +of the 1D Schrodinger equation. + +i h bar dt of psi. + +Now our wave function is a +function of x and y and z. + +There's some finite +probability then + +to find a particle +at some position. + +That position is labeled +by the three coordinates. + +Is equal to-- and of t. + +Is equal to-- well, +I'm actually write + +this in slightly different form. + +This is going to be easier +if I use vector notation. + +So I'm going to write +this as psi of r and t, + +where r denotes the +position vector, + +is equal to the energy +operator acting on it. + +And P is just equal to +minus i h bar the gradient. + +So this is minus i h bar +squared, or minus h bar squared + +upon 2m gradient squared plus +u of x or now u of r psi of r + +and t. + +Quick question, what +are the units or what + +are the dimensions +of psi of r in 3D? + +AUDIENCE: [INAUDIBLE]. + +PROFESSOR: Yeah, one over +length to the root three halves. + +And the reason is this norm +squared gives us a probability + +density, something +that when we integrated + +over all positions in a +region integral d 3x is going + +to give us a number, +a probability. + +So its actual +magnitude must be-- + +or its dimension must +be 1 over L to the 3/2. + +Just the cube of +what it was in 1D. + +And as you'll see +on the problems set + +and as we'll do in a couple +lectures down the road, + +it's convenient sometimes +to work in Cartesian, + +but it's also +sometimes convenient + +to work in spherical +coordinates. + +And it does not matter. + +And here's a really +deep statement + +that goes way beyond +quantum mechanics. + +It does not matter which +coordinates you work in. + +You cannot possibly get a +different answer by using + +different coordinates. + +So we're going to be ruthless +in exploiting coordinates that + +will simplify our problem +throughout the rest + +of this course. + +In the notes is it a short +discussion of the form + +of the Laplacian, +or the gradient + +squared in Cartesian spherical +and cylindrical coordinates. + +You should feel free to use +any coordinate system you + +want at any point. + +You just have to be +consistent about it. + +So let's work out a +couple of examples. + +And here are all +we're going to do + +is apply exactly the same +logic that we see over + +and over in 1D to +our 3D problems. + +So the first example is +a free particle in 3D. + +So before I get started +on this, any questions? + +Just in general 3D questions? + +OK. + +So this stuff starts off easy. + +And I'm going to work in +Cartesian coordinates. + +And a fun problem is +to repeat this analysis + +in spherical coordinates, +and we'll do that later on. + +OK, so free particle +in 3D, so what + +is the energy eigenfunction +equation look like? + +We want to find-- the +Schrodinger equation has + +exactly the same +structure as before. + +It's a linear +differential equation. + +So if we find the eigenfunctions +of the energy operator, + +we can use superposition to +construct the general solution, + +right? + +So exactly as in 1D, I'm going +to construct first the energy + +eigenfunctions , and then use +them in superposition to find + +a general solution to +the Schrodinger equation. + +OK? + +So let's construct the +energy eigenfunctions. + +So what is the energy +eigenvalue equation look like? + +Well, E on psi is equal to +minus h bar squared upon 2m. + +And in Cartesian, the +Laplacian is derivative respect + +to x squared plus +derivative with respect + +to y squared plus derivative +with respect to z squared. + +And we have no potential, +so this is just psi. + +So that would be energy +operator acting on it. + +And the eigenvalue +equation is at a constant, + +the energy E on psi +satisfies this equation. + +I'm going to write +this phi sub e + +to continue with +our notation of phi + +being the energy eigenfunctions. + +It of course, doesn't +matter what I call it, + +but just for consistency I'm +going to use the letter phi. + +So this is a very easy +equation to solve. + +In particular, it has +a lovely property, + +which is that it's separable. + +OK? + +So separable means +the following. + +It means, look, I note, I just +observed that this differential + +equation can be written +as a sum of terms + +where there's a derivative with +respect to only one variable. + +There's a differential +operator with respect + +to only one variable and +another differential operator + +with respect to only one +variable added together. + +And when you see that, +you can separate. + +And here's what I +mean by separate. + +I'm going to just construct. + +I'm not going to say that +this is a general solution. + +I'm just going to +try to construct + +a set of solutions of +the following form. + +Psi E of x, y, and +z is equal to psi + +E-- I will call this psi +sub x of x times phi sub + +y of y times phi sub z of z. + +And if we take this and we plug +it in, let's see what we get. + +This gives us that E on phi E +is equal to minus h bar squared + +upon 2m. + +Well the dx squared +acting on phi sub e + +is only going to hit this guy. + +So I'm going to get phi x +prime prime phi y phi z. + +Plus from the next term phi +y prime prime phi x phi z. + +And from the next term phi +z prime prime phi x phi y. + +But now I can do a sneaky thing +and divide the entire equation + +by phi sub e. + +Phi sub e is phi x phi y phi z. + +So if I do so, I lose the phi +y phi z, and I divide by phi x. + +And in this term, when I +divide by phi x phi y phi z, + +I lose the x and z, and I have +a left over phi sub y, or phi y. + +And similarly here, +phi sub z upon phi z. + +Everyone cool with that? + +Yeah? + +AUDIENCE: Can we also +lose the [INAUDIBLE]? + +PROFESSOR: I don't think so. + +Minus h bar squared over 2m +just hangs out for the ride. + +So when I take the +derivatives, I get these guys. + +And I have E times the function. + +We could certainly write +this as 2m over h bar squared + +and put it over here. + +That's fine. + +OK, so this is the form +of the equation we have, + +and what does this give us? + +What content does this give us? + +Well, note the following. + +This is a funny system. + +This is a function of x. + +This is a function of y, g +of y only, and not of x or z. + +And this is a function only +of z, and not of x or y. + +Yeah? + +So we have that E, +and let's put this + +as minus 2m over +h bar squared is + +equal to a function of +x plus a function of y + +plus a function of h. + +What does this tell you? + +AUDIENCE: They're all constant. + +PROFESSOR: They're +all constant, right. + +So the important +thing is this equation + +has to be true for every +value of x, y, and z. + +It's a differential equation. + +It's true everywhere. + +It's true here. + +It's true there. + +It's true at every point. + +Yeah? + +So for any value of x, y, and +z, this equation must be true. + +So now imagine I have a +particular solution g at h. + +I'm going to fix y and z +to some particular point. + +I'm going to look right here. + +And here that fixes y and z. + +So these are just some numbers. + +And suppose we +satisfy this equation. + +Then there's a very x +leaving y and z fixed. + +What must be true of f of x? + +AUDIENCE: Constant. + +PROFESSOR: It's got to +be constant, exactly. + +So this tells us that +f of x is a constant. + +I.e. + +phi x prime prime of +over phi x is a constant. + +I'll call it epsilon x. + +And phi y prime prime +of over phi y and this + +is a function of y of x +is equal to epsilon y. + +And actually for-- +yeah, that's fine. + +For fun I'm going +to put in a minus. + +It doesn't matter what +I call this coefficient. + +And similarly for phi z +prime prime z over phi z + +is equal to minus epsilon z. + +So this tells us that +minus 2m upon h bar squared + +e is equal to minus epsilon x +minus epsilon y minus epsilon + +z. + +And any solutions +of these equations + +with some constant value +of epsilon x, epsilon + +y, and epsilon z +is going to give me + +a solution of my original energy +eigenvalue equation, where + +the value of capital +E is equal to the sum. + +And I can take the minus +signs make this plus plus. + +Yeah? + +AUDIENCE: Can +epsilon x, epsilon y, + +and epsilon z-- can +one of them be negative + +if the other's are sufficiently +positive or vice versa? + +Or is that [INAUDIBLE]? + +PROFESSOR: Let's check. + +Let's check. + +So what are the solutions +of this equation? + +Yeah. + +So solutions to +this equation phi + +double-- so let's write this in +a slightly more familiar form. + +This says that phi prime +prime plus epsilon x + +phi is equal to 0, OK? + +But this just tells you +that phi is exponential. + +Phi is equal to a e +to the Ikx kxx plus B + +e to the minus ikxx, +where k squared is + +equal to kx squared +is equal to epsilon x. + +OK? + +So this becomes-- and similarly +for epsilon y and epsilon z, + +each with their own +value of ky and kz + +who squares the +epsilon accordingly. + +So what can you say +about these epsilons? + +Well, the epsilons are +strictly positive numbers. + +So to answer your question. + +So the epsilons +have to be positive. + +OK, so this equation becomes, +though, E is equal to-- I'm + +going to put the h bar squared +over 2m back on the other side. + +h bar squared upon 2m. + +Epsilon x, epsilon y, epsilon z. + +But those are just +Kx squared plus Ky + +squared plus Kz squared. + +Kx squared plus +Ky squared plus Kz + +squared, also known as +h bar squared upon 2m k + +vector squared, where the +wave function, phi sub + +E is equal to some overall +normalization constant times, + +for the first function-- +where did the definition go? + +Right here. + +So from here, phi x is +the exponential with Kx. + +This is an +exponential y with Ky. + +And then the exponential +in z with Kz. + +e to the ikx times x plus +Ky times y plus Kz times z. + +Let me write this as e to the i. + +e to the i. + +Also known as some normalization +constant e to the i k vector + +dot r vector. + +OK? + +So the energy, if we have +a free particle, the energy + +eigenfunctions can +be put in the form, + +or at least we can build energy +eigenfunctions of the form, + +plane waves with some 3D +momentum with energy E + +is equal to h bar squared +k squared upon 2m, + +just as we saw for the free +particle in one dimension. + +And the actual wave +function is nothing + +but a product of +wave functions in 1D. + +Yeah? + +AUDIENCE: What happened +to the minus ikx minus iky + +minus ikz terms? + +PROFESSOR: Good, so here +I just dropped these guys. + +So I just picked examples where +we just picked e to the ikz. + +That's an excellent question. + +So I've done something here. + +In particular, I looked +at a special case. + +And here's an important +lesson from the theory + +of the separable +equations, which + +is that once I separate-- so +if I have a separable equation + +and I find it +separated solution, + +phi E is equal to phi x of +x, phi y of y phi z of z, + +not all functions-- not all +solutions of the equation + +are of this form. + +They're not. + +I had to make that assumption. + +I said suppose it's of +this form right here. + +So this is an assumption. + +OK? + +However, these +form a good basis. + +By taking suitable +linear combinations + +of them, suitable +super positions, + +I can build a completely +general solution. + +For example, as was noted, the +true solution of this equation, + +even just focusing on +the x, is a superposition + +of plus and minus +waves, waves with + +plus positive negative momentum. + +So how do we get that? + +Well, we could +write that as phi is + +equal to e to the ikx +phi y phi z plus e + +to the minus ikx phi y phi z +with the same phi y and phi z. + +So these are actually in there. + +Yeah? + +AUDIENCE: My other +question is so I still + +don't see why any +of the epsilons + +can't have a negative sign. + +You have an exponential, +a real exponential as one + +of your products. + +PROFESSOR: OK, so if we +had a negative epsilon, + +is that wave function +going to be normalizable? + +AUDIENCE: Oh, as r +goes to-- but can you + +just keep the minus term? + +PROFESSOR: In which direction? + +AUDIENCE: Oh, right. + +PROFESSOR: So if it's +converging in this direction, + +it's got to be growing +in this direction. + +And that's not going +to be normalizable. + +And so as usual +with the plane wave, + +we can pick the oscillating +solutions that are also + +not normalizable +to one, but they're + +delta function normalizable. + +And so that's what +we've done here. + +It's exactly the +same thing as in 1D. + +Yeah? + +AUDIENCE: So does this mean +that any superposition of plane + +waves with wave vector +equal in magnitude + +will also be an eigenfunction +of the same energy? + +PROFESSOR: Absolutely. + +Awesome. + +Great observation. + +So the observation is this. + +Suppose I take K, +I'll call it K1. + +So this is a vector +such that K1 squared + +times h bar squared +over 2m is equal to E. + +Now there are many vectors k +which have the same magnitude, + +but not the same direction. + +So we could also make this equal +to h bar squared K2 squared + +vector squared over 2m where K2 +is not equal to K1 as a vector, + +although they share +the same magnitude. + +So that's interesting. + +So that looks a lot like before. + +In 1D, we saw that if +we have k or minus k, + +these have the same energy. + +All right? + +Now if we have any K, +K1-- so this is 1D. + +In 3D, if we have K1 and +K2 with the same magnitude + +and the same energy, +they're degenerate. + +That's interesting. + +Why? + +Why do we have this +gigantic degeneracy + +of the energy eigenfunctions +for the free particle in three + +dimensions? + +Yeah? + +AUDIENCE: Well, there +are an infinite number + +of directions it could be going +in with the same momentum. + +PROFESSOR: Awesome. + +So this is clearly true that +there are an infinite number + +of momenta with +the same magnitude. + +So there are many, +many, but why? + +Why do they have +the same energy? + +Couldn't they have +different energy? + +Couldn't this one have +a different energy? + +AUDIENCE: [INAUDIBLE]. + +PROFESSOR: Excellent, +it's symmetric. + +The system is invariant +under rotation. + +Who are you to say this +is the x direction? + +I call it y. + +Right? + +So the system has a symmetry. + +The symmetry is rotations. + +And when we have +a symmetry, that + +means there's an operator, +a unitary operator, which + +affects that rotation, +the rotation operator. + +It's the operator +that takes a vector + +and rotates in some +particular way. + +We have a unitary +operator that's + +a symmetry that means it +commutes with the energy + +operator. + +But if it commutes with +the energy operator, + +we get can degeneracies. + +We can get states that are +different states mapped + +to each other under our unitary +operator, under our rotation. + +We get states which are +different states manifestly. + +But which have the +same energy, which + +are shared energy eigenvalues. + +Cool? + +And this is a really lovely +example, both in 1D and 3D, + +that when you have a symmetry, +you get degeneracies. + +And when you have +a degeneracy, you + +should be very +suspicious that there's + +a symmetry hanging around, +lurking around ensuring it, OK? + +And this is an +important general lesson + +that goes way beyond the +specifics of the free particle. + +Yeah? + +AUDIENCE: So that +occurs in systems + +with bound states [INAUDIBLE]? + +PROFESSOR: Yeah, it occurs +in systems with bound states + +and systems with +non bound states. + +So here we're talking +about a free particle. + +Certainly not bound. + +And its true. + +For bound states, we'll +also see that there + +will be a degeneracy +associated with symmetry. + +Now your question is a +really, really good one, + +because what we found-- let +me rephrase the question. + +The question is, look, in +1D when we had bound states, + +there was no degeneracy. + +Didn't matter what +you did to the system. + +When you had bound states, bound +states were non degenerate. + +In 3D, we see that when +you have a free particle, + +you again get degeneracy. + +In fact, you get a heck +of a lot more degeneracy. + +You get a sphere's worth. + +Although actually, that's a +sphere in 0 dimension, right? + +It's a 0 dimensional +sphere, two points. + +So you get a sphere's +worth of degenerate states + +for the free particle. + +Well, what about bound states? + +Are bound states non +degenerate still? + +Fantastic question. + +Let's find out. + +So let's do the +harmonic oscillator. + +Let's do the 3D harmonic +oscillator to check. + +So the 3D harmonic oscillator, +the potential is h bar squared. + +And let's pick for fun the +rotationally symmetric 3D + +harmonic oscillator. + +m omega squared upon 2 x squared +plus y squared plus z squared. + +This could also be written m +omega squared upon 2 r squared. + +So I could write it in +spherical coordinates + +or in Cartesian coordinates. + +This is really in +vector notation. + +Doesn't matter. + +It's the same thing. + +3D harmonic oscillator. + +So what you immediately deduce +about the form of the energy + +eigenfunctions? + +Well, we have that E phi E +is equal to P squared over + +minus h bar squared +over 2m-- so here's + +the energy eigenvalue +equation-- times + +dx squared plus dy squared plus +dz squared plus m omega squared + +upon 2 times x squared plus y +squared plus z squared phi E. + +But I can put this +together in a nice way. + +This is minus h bar +squared upon 2m dx squared + +plus m omega squared upon 2 +x squared plus ditto for y + +plus ditto for z phi E. Yeah? + +Everyone agree? + +So this is differential +operator that only involves x. + +Doesn't involve y or z. + +Ditto y, but no x or z. + +And ditto z, but no x or y. + +Aha, this is separable +just as before. + +So now we have a +nice separable system + +where I want to solve the +equations 3 times, once + +for x, y, and z. + +And I'm just going +to write it for x, y, + +and z epsilon sub x phi x is +equal to minus h bar squared + +over 2m dx squared plus +m omega squared upon 2 x + +squared phi sub x. + +And ditto for x, y, z. + +And then phi E is going +to be equal to phi + +x of x, phi y of y, +and phi z of z, OK? + +Where E is equal to epsilon x +plus epsilon y plus epsilon z. + +Note that I've used a slightly +different definition of epsilon + +here as before. + +Here it's explicitly +the energy eigenvalue. + +So what this is +telling is, look, + +we know what this equation is. + +This equation is +the same equation + +we ran into in the 1D +harmonic oscillator. + +It's exactly the 1D +harmonic oscillator problem. + +So the solution to the 3D +harmonic oscillator problem + +can be written for +energy eigenfunctions, + +can be constructed +by taking a harmonic + +oscillator in the x direction-- +and we know what those are. + +There's a tower of them. + +There's a ladder of them +created by the raising operator + +and lowered by the +lowering operator. + +And similarly for y, +and similarly for z. + +So I'm going to write +this slightly differently + +in the same place as phi sub +E is equal to phi sub nx of x. + +The state with energy E sub nx. + +Phi sub ny of y. + +Phi sub nz of z. + +Where these are all +the single dimension, + +one dimensional harmonic +oscillator eigenfunctions. + +And E is equal to Ex E sub nx +plus E sub ny plus E sub nz. + +OK? + +So let's look at the +consequences of this. + +So first off, does anyone +have any questions? + +I went through +the kind of quick. + +Any questions about that? + +If you're not comfortable +with separable equations, + +you need to become super +comfortable with separable + +equations. + +It's an important technique. + +We're going to use it a lot. + +So the upshot is that +if I write-- in fact, + +I'm going to write that in +slightly different notation. + +If I write phi E +is equal to phi n + +of x, where it's the-- and phi +l of y and phi m of z-- actually + +that's a stupid ordering. + +Let's try that again. + +l, m, n. + +That is the +alphabetical ordering. + +With the energy is +now equal to-- we + +know the energy is of a +state with of the harmonic + +oscillator with +excitation number l. + +It's h bar omega, the overall +omega, times l plus 1/2. + +But from this guy it's +got excitation number m, + +so energy of that is h bar +omega m plus 1/2 plus m. + +And so now that's plus 1. + +And for this guy +similarly, h bar omega + +n plus n and now plus +1/2 again plus 3/2. + +This is a basis of solutions +of the energy eigenfunction + +equations. + +These are the solutions of +the energy eigenfunctions + +for the 3D harmonic oscillator. + +And now here's the question. + +The question that +was asked is, look, + +there are no degeneracies +in bound states in 1D. + +Here we have manifestly +a 3D bound state system. + +Are there degeneracies? + +AUDIENCE: Yes. + +PROFESSOR: Yeah, +obviously, right? + +So for example, if I call +l1 this 0 and this 0. + +Or if I call this 010 or 001, +those all have the same energy. + +They have the energy h bar +omega 0 times 1 plus 3/2 or 5/2. + +So let's look at this +in a little more detail. + +Let's write a list +of the degeneracies + +as a function of the energy. + +So at energy what's +the ground state energy + +for the 3D harmonic oscillator? + +3 halves h bar omega. + +It's three times +the ground state + +energy for the single +1D harmonic oscillator. + +So 3/2 h bar omega. + +Yeah? + +AUDIENCE: [INAUDIBLE]. + +PROFESSOR: Good, the way +we arrived that this was we + +found that the energy-- so +the energy operator acting + +on the 3D wave +function is what I + +get by taking the +energy operator in 1D + +and acting on the wave function, +and the energy operator in y + +acting on the wave function, +the energy operator in z acting + +on the wave function, where +the energy operator for each + +of those is the 1D +harmonic oscillator + +with the same frequency. + +OK? + +And then I separated. + +I said look, let +the wave function, + +the 3D wave function, since +I know this is separable + +and each separated part +of the wave function + +satisfies the 1D harmonic +oscillator equation, + +I know what the eigenfunctions +of the 1D harmonic oscillator + +energy eigenvalue problem are. + +They are the phi n's. + +And so I can just take +my 3D wave function. + +I can say the 3D wave function +is going to be the separated + +form, the product +of 1D wave function + +in x, a 1D wave function in +y, and 1D wave function in z. + +Cool? + +So now let's look back +at what let's think + +about what happens when I +take the energy operator + +and I act on that [INAUDIBLE]. + +When I take the 3D +energy operator, which + +is the sum of the three +1D energy operators, + +harmonic oscillator +energy operators. + +When thinking I'm going +to act on this guy, + +the first one, which only +knows about the x direction, + +sees the y and z +parts as constants. + +And it's a phi x, and +what does it give us back? + +E on phi x is just h bar +omega n plus one half. + +Ditto for this guy. + +And then the energy +operator in 3D + +is the sum of the three +1D energy operators. + +So that tells us the energy is +the sum of the three energies. + +Is that cool? + +OK good. + +Other questions? + +Yeah? + +AUDIENCE: Is the number of +degeneracies essentially + +[INAUDIBLE] of number theory. + +PROFESSOR: Ask me +that after class. + +So let's look at +the degeneracies + +as a function of the energy. + +So at the lowest possible +energy, 3/2 omega, what states + +can I possibly have? + +I'm going to label the states by +the three numbers, l, m, and n. + +So this is just the +ground state 0 0 0. + +So is that degenerate? + +No, because there's +just the one state. + +What about at the next level? + +What's the next allowed energy? + +AUDIENCE: 5/2. + +PROFESSOR: 5/2. + +OK, 5/2. + +So at 5/2 what +states do we have? + +Well, we have 1 0 0. + +But we also have 0, 1, 0. + +And we also 0 0 1. + +Aha, this is looking good. + +What does this +correspond to physically? + +This says you have +excitation, so you've + +got a node in the x direction. + +But your Gaussian in +the y and z directions. + +This one says your Gaussian +in the x direction. + +You have a node in the y +direction as a function of y, + +because it's phi 1 of y. + +And you're Gaussian +in the z directions. + +And this one says you have 1 +excitation in the z direction. + +So they sound sort of +rotated from each other. + +That sounds promising. + +But in particular, what +we just discovered sort of + +by construction +is that there can + +be degeneracies among +bound states in 3D. + +This was not possible +in 1D, but it + +is possible in +3D, which is cool. + +But we've actually learned more. + +What's the form of +the degeneracies? + +So here it looks like they're +just rotations of each other. + +You call this x, I call it +y, someone else calls it z. + +These can't possibly +look different functions + +because they're just +rotations of each other. + +However, things get +a little more messy + +when you write, well, +what's the next level? + +What's the next energy +after 5/2 h bar omega? + +7/2 h bar omega, exactly. + +7/2. + +And that's not so bad. + +So for that one, we get +2 0 0, 0 2 0, 0 0 2. + +But is that it? + +AUDIENCE: No. + +PROFESSOR: What else do we get? + +1 1 0, 0 1 1, 1 0 1. + +So first off, let's +look at the number. + +The degeneracy number +here-- I'll call this d sub + +0-- the degeneracy of the +ground state is 1, OK? + +The degeneracy-- +and in fact, I'm + +going to write this as a table-- +the degeneracy as level n. + +So for d0 is equal to 1. + +d1 is equal to 3. + +And d2 is equal to 6. + +Now it's less clear +here what's going on, + +because is this just +this guy relabelled? + +No. + +So this is weird, +because we already + +said that the reason we expect +that there might be degeneracy, + +is because of +rotational symmetry. + +The system is +rotationally invariant. + +The potential, which is the +harmonic oscillator potential, + +doesn't care in what direction +the radial displacement + +vector is pointing. + +It's rotationally symmetrical. + +When we have symmetry-- +on general grounds, when + +we have a symmetry, we +expect to have degeneracies. + +But this are kind of +weird, because these + +don't seem to be simple +rotations of each other, + +and yet they're degenerate. + +So what's up with that? + +Question? + +Yeah? + +AUDIENCE: [INAUDIBLE] Gaussian +in certain directions? + +PROFESSOR: Yeah, sure OK. + +So let me just explain what +this notation means again. + +So by 1 0 0, what I mean is +that the number l is equal to 1, + +the number m is equal +to 0, n is equal to 0. + +That means that +the wave function + +phi 3D is equal to phi 1 of +x, phi 0 of y, phi 0 of z. + +But what's phi 0 of z? + +What's a Gaussian +in the z direction? + +Phi 0 of y. + +That's the ground state +in the y direction + +of the harmonic oscillator. + +It's Gaussian in +the y direction. + +If I wanted x, that's +not the ground state. + +That's the excited state. + +And in particular, sort of being +a Gaussian it goes through 0. + +It has a node. + +So this wave function is +not rotationally invariant. + +It as a node in the x direction, +but no nodes and y and z + +direction. + +And similarly for these guys. + +Did that answer your questions? + +Great. + +OK, so we have +these degeneracies, + +and they beg an explanation. + +And if you look +at the next level, + +it turns out that d3-- and +you can do this quickly + +on a scrap of +paper-- d3 is 10, OK? + +And they go on. + +And if you keep +writing this list out, + +I guess it goes up-- +what's the next one? + +15. + +21, yeah. + +So this has a simple +mathematical structure, + +and you can very quickly +convince yourself + +of the form of this degeneracy. + +dn is n n plus 1 over 2. + +So let's just make +sure that works. + +1 1 plus 1 over 2. + +Sorry I should +really call this 1. + +n plus 1, n plus 2 +if I count from 0. + +So for 0, this is going to +give us 1 times 2 over 2. + +That's 1. + +That works. + +So for 1 that gives +2 times 3 over 2, + +which is 3, and so +on and so forth. + +So where did this come from? + +This is something we're +going to have to answer. + +Why that degeneracy? + +That seems important. + +Why is it that number? + +Why do we have that +much degeneracy? + +But the thing I really want +to emphasize at this point + +is that there's an absolutely +essential deep connection + +between symmetries +and degeneracies. + +If we didn't have symmetry, +we wouldn't have degeneracy, + +and we can see that +very easily here. + +Imagine that this potential +was not exactly symmetric. + +Imagine we made it slightly +different by adding + +a little bit of extra +frequency to z direction. + +Make the z frequency +slightly different. + +Plus m omega tilde +squared upon 2 z + +squared, where omega tilde +is not equal to omega 0. + +OK? + +The system is still +separable, but this guy + +has frequency omega 0. + +The x part has omega 0. + +This has omega 0. + +But this has omega tilde. + +OK? + +And so exactly the same +argument is going to go through, + +but the energy now is going +to have a different form. + +The energy is going to have h +bar omega-- h bar omega 0 times + +l plus m plus 1. + +But from the z part +it's going to have + +plus h bar omega tilde +times n plus 1/2. + +And now these +degeneracies are going + +to be broken, because +this state will not + +have the same +energy as these two. + +Everyone see that? + +When you have symmetry, +you get to degeneracy. + +When you don't have a symmetry, +you do not get degeneracy. + +This connection is +extremely important, + +because it allows +you to do two things. + +It allows you to +first not solve things + +you don't need to solve for. + +If you know there's a symmetry, +solve it once and then compute + +the degeneracy and you're done. + +On the other hand, +if you have a system + +and you see just manifestly +you measure the energies, + +and you measure that the +energies are degenerate, + +you know there's a symmetry +protecting those degeneracies. + +You actually can't +be 100% confident, + +because I didn't prove +that these are related + +to each other, but you +should be highly suspicious. + +And in fact, this is an +incredibly powerful tool + +in building models +of physical systems. + +If you see a degeneracy or +an approximate degeneracy, + +you can exploit that to learn +things about the underlying + +system. + +Yeah? + +AUDIENCE: So we just +add the different omega + +to each omega +[INAUDIBLE] number there + +is still a possibility +to get a degeneracy. + +PROFESSOR: Exactly. + +So it's possible for these +omegas to be specially tuned + +so that rational combinations +of them give you a degeneracy. + +But it's extraordinarily +unlikely for that + +to happen accidentally, +because they + +have to be rationally +related to each other, + +and the rationals are a set +of measures 0 in the reels. + +So if you just randomly +pick some frequencies, + +they'll be totally +incommensurate, + +and you'll never +get a degeneracy. + +So it is possible to have +an accidental degeneracy. + +Whoops, just pure coincidence. + +But it's extraordinarily +unlikely. + +And as you'll see when you +get to perturbation theory, + +it's more than unlikely. + +It's almost impossible. + +So it's very rare that you +get accidental degeneracy. + +It happens, but it's rare. + +Other questions? + +OK, nothing? + +OK so here we're now +going to launch into-- + +so this leads us into +a very simple question. + +At the end of the +day, the degeneracies + +that we see for the 3D +free particle, which + +is a whole sphere's +worth of degeneracy, + +and the degeneracy we see for +the 3D harmonic oscillator, + +the bound states, +which is discrete, + +but with more and +more degeneracy + +the higher and +higher energy you go. + +Those we're blaming, +at the moment, + +on a symmetry, on +rotational symmetry, + +rotational invariance. + +So it seems wise +to study rotations, + +to study rotational invariance +and rotational transformations + +in the first place. + +In the first part of the +course, in 1D quantum mechanics, + +we got an awful lot of juice +out of studying translations. + +And the generator of +translations was momentum. + +So we're going to do +the same thing now. + +We're going to study +rotations and the generators + +of rotations, which are the +angular momentum operators, + +and that's going to occupy +us for the rest of today + +and Thursday. + +Yeah? + +AUDIENCE: So your +rotational symmetry + +will explain a factor of three +in your degeneracy, right? + +But what's the symmetry that +explains the way this grows. + +Because this very +clearly appears + +there's 1 up to a +factor of three. + +And then there's 2 up +to a factor of three. + +And there's even more that's +not even a multiple of three. + +PROFESSOR: Right, +actually so here's + +a very tempting +bit of intuition. + +Very tempting bit of intuition +is going to say the following. + +Look, rotational invariance, +there's x, there's y, + +and there's z. + +It's going to explain +rotations amongst those three. + +So that could only possibly +give you a factor of three. + +But it's important +to keep in mind + +that that's not +correct intuition. + +It's tempting intuition, +but it's not correct. + +And an easy way to see +that its not correct + +is that for the +free particle, there + +is a continuum, a +whole sphere's worth + +of degenerate states +in any energy. + +And all of those are related to +each other by simple rotation + +of the k vector, of +the wave vector, right? + +So the rotational +symmetry is giving us + +a lot more than a +factor of three. + +And in fact, as +we'll see, it's going + +to explain exactly the n +plus 1 n plus 2 over 2. + +OK, so with that +motivation let's + +start talking about +angular momentum. + +So I found this topic +to be not obviously + +the most powerful or interesting +thing in the world when I first + +studied it. + +And my professor +was like no, no, no. + +This is the deepest thing. + +And recently I had a fun +conversation with one + +of my colleagues, +Frank Wilczeck, + +who said yeah, in intro +to quantum mechanics + +the single most interesting +thing is the angular momentum + +and the addition of +angular momentum. + +And something has happened to +me in the intervening 20 years + +that I totally agree with him. + +So I will attempt to convey to +you the awesomeness of this. + +But you have to buy in a little. + +So work with me in the math +at the beginning of this, + +and it has a great payoff. + +OK so the question is, +what is the operator. + +So we're going to talk +about angular momentum now. + +And I want to start with +the following question. + +In the same sense +as we started out + +by asking what +represents position + +and momentum, linear momentum, +in quantum mechanics, what + +represents what operator by +our first, second, or third + +postulate-- I don't even +remember the order now. + +What operator represents angular +momentum in quantum mechanics? + +And let's start by remembering +what angular momentum is + +in classical mechanics. + +So L in classical +mechanics is r cross p. + +In classical mechanics. + +So let's just try this. + +Let's construct that operator. + +This is not the world's most +beautiful way of deriving this, + +but let's just write +down natural guess. + +For in quantum mechanics +what's the operator we want? + +Well, we want a vectors +worth of operators, + +because angular +momentum is a vector. + +It's a vector of +operators, three operators. + +And I'm going to write these +as r vector the operators x, y, + +z cross p the vector +of momentum operators. + +So at this point, you +should really worry, + +because do r and p commute? + +Not so much, right? + +However, the situation is +better than it first appears. + +Let's write this out +in terms of components. + +So this is in components. + +And I'm going to +work, for the moment, + +in Cartesian coordinates. + +So Lx is equal to? + +Lx is equal to? + +You all took mechanics. + +Lx is equal to? + +AUDIENCE: [INAUDIBLE]. + +PROFESSOR: Thank you. + +YPz minus ZPy. + +And that's the curl, the +x component of the curl. + +And similarly, the x component-- +so the way to remember this + +is that its cyclic. + +x, y, z. + +y, z, x. + +So z, p, y. + +PX minus XPz. + +And then we have +z XPy minus YPx. + +So we were worried here about +maybe an ordering problem. + +Is there an ordering +problem here? + +Does it matter if +I write YPz or PZy? + +AUDIENCE: No. + +PROFESSOR: No, because they +commute with each other. + +PZ is momentum for +the z-coordinate, not + +the y-coordinate, and they +commute with each other. + +So there's no ambiguity. + +It's perfectly well defined. + +So we're just going +to take this to be + +the definition of the components +of the angular momentum + +operator Lx, Ly, and Lz. + +And just for fun, I +want to write this out. + +So because we know that Px, +Py, and Pz can be expressed + +in terms of derivatives +or differential operators, + +we can write the same operator +in Cartesian coordinates + +in the following way. + +So clearly we could +write this as Y d dx i + +upon h bar-- or +sorry, h bar upon i. + +And z h bar upon i d dy. + +So we could write that +in Cartesian coordinates + +as a differential operator. + +But we can also write this +in spherical coordinates. + +I'm just going to take +a quick side note just + +to write down what it is. + +If we did this +spherical coordinates, + +it's particularly +convenient to write-- + +let me just write +Lz for the moment. + +This is equal to minus i h bar +derivative with respect to phi, + +where the coordinates, +[INAUDIBLE] + +coordinates and spherical +coordinates in this class + +is theta is going +to be the angle down + +from the vertical +axis, from the z-axis. + +And phi is going to be +the angle of a period 2pi + +that goes around +the equator, OK? + +Just to give you a name. + +This is typically what +physicists call them. + +This is typically not what +mathematicians call them. + +This leads to +enormous confusion. + +I apologize for my field. + +So here it is. + +I can also construct +the operator associated + +with the square of the momentum. + +And why would we care about +the square of the momentum? + +Well, that's what shows up +in the Hamiltonian, that's + +what shows up in the energy. + +So I can construct the operator +for the square of the momentum + +and write it, and it takes +a surprisingly simple form. + +When I see surprisingly simple, +you might disagree with me, + +but if you actually do +the derivation of this, + +it's much worse in between. + +1 over sine theta +d theta sine theta + +d theta plus 1 over sine +squared theta d phi. + +Couple quick things. + +What are the dimensions +of angular momentum? + +Length and momentum. + +What else has units +of angular momentum? + +AUDIENCE: h bar. + +PROFESSOR: Solid. h +bar, dimensionless. + +Angular momentum squared, +angular momentum squared. + +OK, great. + +So that's going to +be very convenient. + +h bars are just going to +float around willy nilly. + +OK, so suppose I ask you +the following-- bless you. + +Suppose I ask you the +following questions. + +I say look, here are the +operators of angular momentum. + +This is Lz. + +We could have written down +the same expression for Lx, + +and a Ly, and L squared. + +What are the eigenfunctions +of these operators? + +Suppose I ask you this question. + +You all know how to +answer this question. + +You take these operators-- +so for example, + +if I ask you what are +the eigenfunctions of Lz? + +Well, that's not so bad, right? + +The eigenfunction +of Lz is something + +where Lz on phi-- +I'll call little m-- + +is equal to minus I h +bar d d theta phi sub m. + +But I want the +eigenvalue, so I'll + +call this h bar +times some number. + +Let's call it m, because +Lz is an angular momentum. + +It carries units of +h bar, and its h bar + +times some number which is +dimensional, so we'll call it + +m. + +And we all know the +solution of this equation. + +The derivative is equal +to a constant times-- + +we can lose the h bar. + +We get a minus i, +so we pick up an i. + +So therefore phi sub m is +equal to some constant times e + +to the im phi. + +What can we say about m? + +Well, heres an important +thing-- oh shoot. + +I'm using phi in so many +different ways here. + +Let's call this not +phi, because it's + +going to confuse +the heck out of us. + +Let's call it Y. So +we'll call it Y sub m. + +Why not? + +It's not my joke. + +This goes back to a bunch of-- +yeah well, it goes way back. + +So phi is the variable. + +Y is the deciding eigenfunction +of Lz, and that's great. + +But what can you say about m? + +Well phi is the variable +around the equator + +is periodic with period 2pi. + +And our wave function had +better be single valued. + +So what does that +tell you about m? + +Well, under phi goes +to phi plus 2pi. + +This shifts by im 2pi. + +And that's only one to +make a single valued + +if m is an integer. + +So m has to be an integer. + +m is an integer. + +Now we did that for Lz. + +We found the +eigenfunctions of Lz. + +What about finding the +eigenfunctions L squared? + +Exactly the same thing. + +We're going to solve +the eigenvalue equation, + +but it's going to be +horrible, horrible to find + +these functions, right? + +Because look at this. + +1 over sine squared d d phi. + +And then 1 over sine +d theta sine d theta. + +This is not going to +be a fun thing to do. + +So we could just brute +force this, but let's not. + +Let's all agree that +that's probably a bad idea. + +Let's find a better way to +construct the eigenfunctions + +of the angular +momentum operators. + +So let's do it. + +So we ran into a +situation like this + +before when we dealt with +the harmonic oscillator. + +There was a +differential equation + +that we wanted to solve. + +And OK, this one isn't nearly +as bad, not nearly as bad + +as that one would have been. + +But still it was more useful +to work with operator methods. + +So let's take a hint from that +and work with operator methods. + +So now we need to study the +operators of angular momentum. + +So let's study them in +a little more detail. + +So something you're going +to show in your problem set + +is the following. + +The commutator of Lx with Ly +takes a really simple form. + +This is equal to i h bar-- +let's just do this out. + +Let's do this commutator. + +We're OK. + +So Lx with Ly, this is +equal to the commutator + +of YPz minus ZPy with +Ly ZPx minus XPz. + +So let's look at +these term by term. + +So the first one is YPz ZPx. + +YPz ZPx. + +That's a Px. + +Sorry, ZPy. + +ZPx, this term. + +X, good. + +That's the first commutator. + +The second commutator, it can +be YPz an XPz minus YPz XPz. + +And then these +commutators, the next two, + +are going to be ZPy with ZPx. + +And finally ZPy. + +And that's minus +and this is a plus. + +ZPy and XPz. + +OK, so let's look at these. + +These look kind +of scary at first. + +But in this one +notice the following. + +This is XPz ZPx minus ZPx YPz. + +But what you say about Y with +all these other operators? + +Y commutes with all of them. + +So in each term I +could just pull Y + +all the way out to one side. + +Yeah? + +So I could just pull out this +Y. So for the first term, + +I'm going to write this as +Y commutator PZ with ZPx. + +And let me just do +that explicitly. + +There's no reason to. + +So this is YPz +ZPx minus ZPx YPz. + +And I can pull the Y out front, +because this commutes with Px + +and with Z. So I can make this +Y times PZ ZPx minus ZPx Pz. + +But now note that I can +do exactly the same thing + +with the Px. + +Px commutes with z. + +Px commutes with Pz. + +And it commutes with y. + +So I can pull the px +from each term out. + +Px Y. And now I lose the Px. + +I lose the Px. + +But now this is looking good. + +This is Px times Y. And Pz +minus ZPz PZz minus ZPz. + +This is also known as PXy +times commutator of PZ with Z. + +And what is this equal to? + +Let's get our signs right. + +This is Px with Y +time-- OK, we all + +agree that this is going +to have an h bar in it. + +Let's write units. + +There's going to be an i. + +And is it a plus or minus? + +Minus. + +OK, good. + +So we get minus h bar XPy. + +So this term is going to give +us minus i h bar Py XPx times Y. + +And let's look at this term. + +OK, this is Y, and Y commutes +with PZx and PZ, right? + +So I could just pull out the y. + +And x commutes with everything, +so I can pull out the x. + +And I'm left with the +commutator of Pz with Pz. + +What's the commutator +of Pz with Pz? + +AUDIENCE: 0. + +PROFESSOR: 0. + +This term gives me a 0. + +Similarly here, Py +commutes with everything. + +Z ZPx. + +Px commutes with everything. + +Z ZPy. + +So I can pull out the Px Py, +and I get Z commutator Z, + +and what's that? + +AUDIENCE: 0. + +PROFESSOR: 0. + +So this gives me 0. + +And now this term, ZPy +XPz, the only two things + +that don't commute with each +other are the Z and the Pz. + +The Py and the X +I pull out, so I + +get it a term that's XPy and +the commutator of Z with Pz. + +And what is that +going to give me? + +PyX i h bar. + +Aha, look at what we got. + +This is equal to i h bar times-- +did I screw up the signs? + +XPy minus YPz. + +Oh sorry, Px. + +And what is this equal to? + +AUDIENCE: [INAUDIBLE]. + +PROFESSOR: Yeah, i h bar Lz. + +And more generally, as you'll +show on the problem set, + +you get the following +commutators. + +Once you've done this once, you +can do the rest very easily. + +Lx Ly is-- so Lx with +Ly is i h bar Lz. + +And then the rest can be +got from cyclic rotations + +Ly with Lz is i h bar Lx and +Lz with Lx is i h bar Ly. + +And now here's a fancier one. + +This is less obvious, but +exactly the same machinations + +will give you this result, +and you'll do this again + +on the problems set. + +If I take L squared, +k and L squared + +here is going to be +L squared, I just + +mean Lx squared plus Ly +squared plus Lz squared. + +This is the norm squared of +the vector, the operator form. + +L squared with Lz-- +or sorry, with Lx. + +Yeah, fine. + +Lx is equal to 0. + +So Lx commutes with the +magnitude L squared. + +Similarly L squared, now just +by rotational invariance, + +if Lx commutes +with it, Ly and Lz + +had better also commute +with it, because + +of who you to see what's Lx. + +And L squared with Lz +must be equal to 0. + +Yeah? + +Everyone cool with that? + +And the thing is +we've just-- and I'm + +going to put big +flags around this. + +We've just learned +a tremendous amount + +about the eigenfunctions of +the angular momentum operators. + +Why? + +Let's leave that up. + +So what have we just learned +about the eigenfunctions + +of the angular momentum +operators Lx, Ly, Lz, and L + +squared? + +Anyone? + +We just learned something +totally awesome about them. + +Anyone? + +So can you find simultaneous +eigenfunctions of Lx and Ly? + +AUDIENCE: No. + +PROFESSOR: Not so much. + +They don't commute to 0. + +What about Ly and Lz? + +Nope. + +Lz Lx, nope. + +So you cannot find simultaneous +eigenfunctions of Lx and Ly. + +What about Lx and L squared? + +Yes. + +So we can find +simultaneously eigenfunctions + +of L squared and Lx. + +OK, what about can we find +simultaneous eigenfunctions + +of L squared and Ly? + +Yep. + +Exactly. + +What about L +squared, Ly, and Lz? + +Nope. + +No such luck. + +And this leads us to +the following idea. + +The idea is a complete set +of commuting observables. + +And here's what this +idea is meant to contain. + +You can always write +down a lot of operators. + +So let me step back and +ask a classical question. + +Classically, suppose I have a +particle in three dimensions, + +a particle moving around in +this room, non relativistic, + +familiar 801. + +I have a particle moving +around in this room. + +How much data must +I specify to specify + +the configuration +of this system? + +Well, I have to tell you +where the particle is, + +and I have to tell you what +its momentum is, right? + +So I have to tell you the +three coordinates and the three + +momenta. + +If I give you five numbers, +that's not enough, right? + +I need to give you +six bits of data. + +On the other hand, if I +give you seven numbers, + +like I give x, y, z, Px, Py, +Pz, and e, that's over complete. + +Right? + +That was unnecessary. + +So in classical +mechanics, you can + +ask what data must you +specify to completely specify + +the state of the system. + +And that's usually pretty easy. + +You specify the +number coordinates + +and the number of momenta. + +In quantum mechanics, we ask +a slightly different question. + +We ask, in order to specify +the state of a system, + +we say we want to specify +which state it is. + +You can specify +that by saying which + +superposition in a +particular basis. + +So you pick a basis, +and you specify + +which particular +superposition, what + +are the eigenvalues of +the operators you've + +diagonalized in that basis? + +So another way to phrase +this is for a 1D problem, + +say we have just a +simple 1D problem. + +We have X and we have P. What +is a complete set of commuting + +operators? + +Well, you have to +have enough operators + +so that the eigenvalue +specifies a state. + +So X would be-- is that enough? + +So if I take the operator +X and I say look, + +my system is in the state +with an eigenvalue X not of X, + +does that specify the +state of the system? + +It tells you the particles +are in a delta function state + +right here. + +Does that specify the state? + +AUDIENCE: Yes. + +PROFESSOR: Fantastic, it does. + +Now what if I tell +you instead, oh it's + +in a state of definite P. +Does that specify the state? + +Absolutely. + +Can I say it's in a state with +definite X and definite P? + +AUDIENCE: No. + +PROFESSOR: No. + +These don't commute. + +So a complete set of commuting +observables in this case + +would be either X +or P, but not both. + +Yeah? + +Now if we're in three +dimensions, is x a complete set + +of commuting observables? + +AUDIENCE: No. + +PROFESSOR: No, because +it's not enough. + +You tell me that it's +X, that doesn't tell me + +what state it is +because it could + +have y dependence +or z dependence. + +So in 3D, we take, for +example, x, and y, and z. + +Or Px, and Py, and Pz. + +We could also pick +z, and Px, and y. + +Are these complete? + +If I tell you I have +definite position in z, + +definite position in y, +and definite momentum in x? + +Does that completely +specify my state? + +AUDIENCE: Yes. + +PROFESSOR: Yeah, +totally unambiguously. + +e to the ikx delta of y delta +of z totally fixes my function, + +completely specifies it. + +If I'd only picked +two of these, it + +would not have been complete. + +It would have told +me, for example, + +e to the ikx delta of y, +but it doesn't tell me + +how it depends on z, how +the wave functions on z. + +And if I added another +operator, for example, Py, + +this is no longer commuting. + +These two operators +don't commute. + +So a complete set of +commuting observables + +can be thought of as +the most operators + +you can write down that +all commute with each other + +and the minimum number +whose eigenvalues completely + +specify the state of the system. + +Cool? + +OK. + +So with all that said, +what is a complete set + +of commuting observables for +the angular momentum system? + +Well, it can't be any +two of Lx, Ly, and Lz. + +So let's just pick one. + +I'll call it Lz. + +I could've called it Lx. + +It doesn't matter. + +It's up to you +what axis is what. + +I'll just call it +Lz conventionally. + +And then L squared +also commutes, + +because L squared +commutes with Lx. + +It commutes Ly and with Lz. + +So this actually +forms a complete set + +of commuting observables for +the angular momentum system. + +Complete set of +commuting observables + +for angular momentum. + +So this idea will come +up more in the future. + +And here is going to +be the key [INAUDIBLE]. + +So we'd like to use +the following fact. + +We want to construct +the eigenfunctions + +of our complete set +of-- yeah, question? + +AUDIENCE: Really +quick can you explain + +how you got that L +squared and Lx commute? + +PROFESSOR: Yeah, I +got it by knowing + +what you're going to write +on your solution set. + +So this is on your problem set. + +So the way it goes-- so there +are fancy ways of doing it, + +but the just direct +way of doing, + +how do you construct +these commutators? + +Is you know what +the operators are. + +You know what L squared is. + +And you know that L +squared is Lx squared + +plus Ly squared plus Lz squared. + +It's built in that +fashion out of x and Py. + +And then I literally just put +in the definitions of Lx, Ly, + +and Lz into that +expression for L squared + +and compute the +commutator with Lx, again, + +using the definition +in terms of Py and z. + +And then you just chug +through the commutators. + +Yeah, it just works out. + +So it's not obvious from +the way I just phrased it + +that it works out like that. + +Later on you'll probably +develop some intuition + +that it should be obvious. + +But for the moment, +I'm just going + +to call it a brute +force computation. + +And that's how you're going +to do it on your problem set. + +So let me tell you +where we're going next. + +So the question I +really want to deal with + +is what are the eigenfunctions? + +So this is where +we're leaving off. + +What are the eigenfunctions +of our complete set + +of commuting variable +L squared and Lz. + +What are these guys? + +And we know that +we could solve them + +by solving the differential +equations using + +those operators, but +that would be horrible. + +We'd like to do something +a little smarter. + +We'd like to use the commutation +relations and the algebra. + +And here a really beautiful +thing is going to happen. + +When you look at these +commutation relations, + +one thing they're telling us +is that we can't simultaneously + +have eigenfunctions +of Lx and Ly. + +However, the way that Lx and Ly +commute together is to form Lz. + +That gives us some information. + +That gives us some +magic, some power. + +And in particular, much like +that moment in the harmonic + +oscillator I said, well +look, we could write down + +these operators as a. + +Well look, we can write +down these operators, + +which I'm going to call +L plus and L minus. + +L plus is going to be +equal to Lx plus i Ly. + +And L minus is going to +be equal to Lx minus I Ly. + +Now Lx, Ly, those +are observables? + +What can you say about +them as operators? + +What kind of operators are +they since they're observables? + +Hermitian, exactly. + +So what's the Hermitian adjoint +of Hermitian plus i Hermitian? + +Hermitian minus i Hermitian. + +OK, good. + +So L minus is the +adjoint of L plus. + +So this is just going +to be a definition. + +Let's take these to be the +definitions of these guys. + +If we take their commutator, +something totally lovely + +happens. + +I'm not going to write +all the commutators. + +I'm just going to +write a couple. + +The first is if I take L squared +and I commute with L plus, + +well, L plus is Lx +plus Ly, and we already + +know that L squared +commutes with Lx + +and it commutes with Ly. + +So L squared +commutes with L plus. + +And similarly for L minus, +it commutes with each term. + +Question? + +Oh, I'm sorry. + +Lx. + +Shoot, that was an x. + +It just didn't look like it. + +Lx minus i Ly. + +So it commutes both +L plus and L minus. + +But here's the +real beauty of it. + +Lz with L plus is +equal to-- well, + +let's just do +dimensional analysis. + +L plus is Lx plus i Ly. + +We know that Lz with Lx +is something like Ly. + +And Lz with Ly is +something like Lx. + +With factors of i's an h bars. + +And when you work out the +commutator, which should only + +take you second, you +get i h bar L plus. + +And similarly, when we +construct Lz and L minus, + +we get minus h bar L minus. + +Are L plus an L minus Hermitian? + +No, they're each +other's adjoints. + +Lz is Hermitian. + +And look at this +commutation relation. + +What does that tell you? + +From the first observation, +if we have an energy + +or if we have an operator +e and an operator a + +that commute in this +fashion, then this + +tells you that the +eigenfunctions of this operator + +are staggered in a the +ladder spaced by h bar. + +The eigenvalues of Lz come +in a ladder spaced by h bar. + +We can raise with +L plus, and we can + +lower with L minus just like +in the harmonic oscillator + +problem. + +And we'll exploit the +rest of the-- we'll + +deduce the rest of the structure +of the angular momentum + +operator eigenfunctions next +time using this computation + +relation. + +See you next time. \ No newline at end of file diff --git a/Het_nd5x4hs.txt b/Het_nd5x4hs.txt new file mode 100644 index 0000000000000000000000000000000000000000..5f7fc97023d8d4b0768f498548db04b09f7e1007 --- /dev/null +++ b/Het_nd5x4hs.txt @@ -0,0 +1,14344 @@ +align:start position:0% + +the following content is provided by mit + + align:start position:0% +the following content is provided by mit + + + align:start position:0% +the following content is provided by mit +opencourseware under a creative commons + + align:start position:0% +opencourseware under a creative commons + + + align:start position:0% +opencourseware under a creative commons +license + + align:start position:0% +license + + + align:start position:0% +license +additional information about our license + + align:start position:0% +additional information about our license + + + align:start position:0% +additional information about our license +and mit opencourseware in general is + + align:start position:0% +and mit opencourseware in general is + + + align:start position:0% +and mit opencourseware in general is +available at ocw.mit.edu + + align:start position:0% + + + + align:start position:0% + +line engineers a line engineer is + + align:start position:0% +line engineers a line engineer is + + + align:start position:0% +line engineers a line engineer is +what you and i would call a practicing + + align:start position:0% +what you and i would call a practicing + + + align:start position:0% +what you and i would call a practicing +engineer + + align:start position:0% + + + + align:start position:0% + +that term is used in distinction to + + align:start position:0% +that term is used in distinction to + + + align:start position:0% +that term is used in distinction to +management + + align:start position:0% + + + + align:start position:0% + +uh who are people who were at one time + + align:start position:0% +uh who are people who were at one time + + + align:start position:0% +uh who are people who were at one time +line engineers + + align:start position:0% +line engineers + + + align:start position:0% +line engineers +for the most part + + align:start position:0% +for the most part + + + align:start position:0% +for the most part +when i say engineer management i'm + + align:start position:0% +when i say engineer management i'm + + + align:start position:0% +when i say engineer management i'm +saying engineering management + + align:start position:0% +saying engineering management + + + align:start position:0% +saying engineering management +okay + + align:start position:0% +okay + + + align:start position:0% +okay +um and + + align:start position:0% +um and + + + align:start position:0% +um and +as you recall from the uh + + align:start position:0% +as you recall from the uh + + + align:start position:0% +as you recall from the uh +challenger case when this vice president + + align:start position:0% +challenger case when this vice president + + + align:start position:0% +challenger case when this vice president +took off his engineering hat and put on + + align:start position:0% +took off his engineering hat and put on + + + align:start position:0% +took off his engineering hat and put on +his management hat and changed the + + align:start position:0% +his management hat and changed the + + + align:start position:0% +his management hat and changed the +decision + + align:start position:0% +decision + + + align:start position:0% +decision +there are + + align:start position:0% +there are + + + align:start position:0% +there are +different points of view + + align:start position:0% +different points of view + + + align:start position:0% +different points of view +and different professional + + align:start position:0% +and different professional + + + align:start position:0% +and different professional +responsibilities that engineers line + + align:start position:0% +responsibilities that engineers line + + + align:start position:0% +responsibilities that engineers line +engineers have as opposed to + + align:start position:0% +engineers have as opposed to + + + align:start position:0% +engineers have as opposed to +engineering managers + + align:start position:0% +engineering managers + + + align:start position:0% +engineering managers +and engineering managers have + + align:start position:0% +and engineering managers have + + + align:start position:0% +and engineering managers have +the greater authority + + align:start position:0% +the greater authority + + + align:start position:0% +the greater authority +uh but uh there is definitely a + + align:start position:0% +uh but uh there is definitely a + + + align:start position:0% +uh but uh there is definitely a +difference in + + align:start position:0% +difference in + + + align:start position:0% +difference in +uh job requirement and + + align:start position:0% +uh job requirement and + + + align:start position:0% +uh job requirement and +uh + + align:start position:0% +uh + + + align:start position:0% +uh +and for this class + + align:start position:0% +and for this class + + + align:start position:0% +and for this class +contract and + + align:start position:0% +contract and + + + align:start position:0% +contract and +uh point of view + + align:start position:0% + + + + align:start 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align:start position:0% + + + + align:start position:0% + +so the nspe came along + + align:start position:0% +so the nspe came along + + + align:start position:0% +so the nspe came along +they were young engineers they were + + align:start position:0% +they were young engineers they were + + + align:start position:0% +they were young engineers they were +almost all line engineers + + align:start position:0% +almost all line engineers + + + align:start position:0% +almost all line engineers +they were idealistic + + align:start position:0% +they were idealistic + + + align:start position:0% +they were idealistic +and they wanted engineering to do all of + + align:start position:0% +and they wanted engineering to do all of + + + align:start position:0% +and they wanted engineering to do all of +the right things even if it meant some + + align:start position:0% +the right things even if it meant some + + + align:start position:0% +the right things even if it meant some +bad things for 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+social movements that led to the + + align:start position:0% +social movements that led to the + + + align:start position:0% +social movements that led to the +creation of the sts and then engineering + + align:start position:0% +creation of the sts and then engineering + + + align:start position:0% +creation of the sts and then engineering +ethics + + align:start position:0% +ethics + + + align:start position:0% +ethics +that movement was sympathetic to the + + align:start position:0% +that movement was sympathetic to the + + + align:start position:0% +that movement was sympathetic to the +nspe + + align:start position:0% +nspe + + + align:start position:0% +nspe +code not to the asc and the others + + align:start position:0% +code not to the asc and the others + + + align:start position:0% +code not to the asc and the others +so eventually they all came as close to + + align:start position:0% +so eventually they all came as close to + + + align:start position:0% +so eventually they all came as close to +nspe as they could get + + align:start position:0% + + + + align:start position:0% + +so uh + + align:start position:0% + + + + align:start position:0% + +so you find this difference between + + align:start position:0% +so you find this difference between + + + align:start position:0% +so you find this difference between +management and line engineer + + align:start position:0% +management and line engineer + + + align:start position:0% +management and line engineer +um + + align:start position:0% + + + + align:start position:0% + +in the university + + align:start position:0% +in the university + + + align:start position:0% +in the university +you can if you observe + + align:start position:0% +you can if you observe + + + align:start position:0% +you can if you observe +uh the + + align:start position:0% + + + + align:start position:0% + +faculty and administration + + align:start position:0% +faculty and administration + + + align:start position:0% +faculty and administration +uh then the likenesses and the + + align:start position:0% +uh then the likenesses and the + + + align:start position:0% +uh then the likenesses and the +differences are going to be very much + + align:start position:0% +differences are going to be very much + + + align:start position:0% +differences are going to be very much +the same between line engineers + + align:start position:0% +the same between line engineers + + + align:start position:0% +the same between line engineers +and managers + + align:start position:0% +and managers + + + align:start position:0% +and managers +uh + + align:start position:0% +uh + + + align:start position:0% +uh +there's this book + + align:start position:0% + + + + align:start position:0% + +there was some books that were very uh + + align:start position:0% +there was some books that were very uh + + + align:start position:0% +there was some books that were very uh +scathing on + + align:start position:0% + + + + align:start 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+when we say uh + + align:start position:0% +when we say uh + + + align:start position:0% +when we say uh +administration versus faculty + + align:start position:0% +administration versus faculty + + + align:start position:0% +administration versus faculty +this is written for the general public + + align:start position:0% +this is written for the general public + + + align:start position:0% +this is written for the general public +they're all the same + + align:start position:0% + + + + align:start position:0% + +that's what this is what this person was + + align:start position:0% +that's what this is what this person was + + + align:start position:0% +that's what this is what this person was +trying to create in the eyes of the + + align:start position:0% +trying to create in the eyes of the + + + align:start position:0% +trying to create in the eyes of the +general public and had good reasons + + align:start position:0% +general public and had good reasons + + + align:start position:0% +general public and had good reasons +he said they're all the same he said so + + align:start position:0% +he said they're all the same he said so + + + align:start position:0% +he said they're all the same he said so +far as we're concerned they all got phd + + align:start position:0% +far as we're concerned they all got phd + + + align:start position:0% +far as we're concerned they all got phd +they were all faculty members at least + + align:start position:0% +they were all faculty members at least + + + align:start position:0% +they were all faculty members at least +at one time + + align:start position:0% +at one time + + + align:start position:0% +at one time +you know when you talk about a college + + align:start position:0% +you know when you talk about a college + + + align:start position:0% +you know when you talk about a college +president can't get a presidency without + + align:start position:0% +president can't get a presidency without + + + align:start 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align:start position:0% +um +and so someone can say the same thing + + align:start position:0% +and so someone can say the same thing + + + align:start position:0% +and so someone can say the same thing +about engineering the profession that + + align:start position:0% +about engineering the profession that + + + align:start position:0% +about engineering the profession that +we're splitting hairs when you talk + + align:start position:0% +we're splitting hairs when you talk + + + align:start position:0% +we're splitting hairs when you talk +about engineering management versus + + align:start position:0% +about engineering management versus + + + align:start position:0% +about engineering management versus +engineers and there is a great area in + + align:start position:0% +engineers and there is a great area in + + + align:start position:0% +engineers and there is a great area in +the university where it's hard for + + align:start position:0% +the university where it's hard for + + + align:start position:0% +the university where it's hard for +everybody to decide + + align:start position:0% +everybody to decide + + + align:start position:0% +everybody to decide +whether + + align:start position:0% +whether + + + align:start position:0% +whether +whether this + + align:start position:0% +whether this + + + align:start position:0% +whether this +whether it whether department chairs + + align:start position:0% +whether it whether department chairs + + + align:start position:0% +whether it whether department chairs +or managers or faculty + + align:start position:0% + + + + align:start position:0% + +varies from institutional institution + + align:start position:0% +varies from institutional institution + + + align:start position:0% +varies from institutional institution +from time to time + + align:start position:0% +from time to time + + + align:start position:0% +from time to time +uh but even and from department to + + align:start position:0% +uh but even and from 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is bad + + align:start position:0% +every so often if the review is bad + + + align:start position:0% +every so often if the review is bad +you're out + + align:start position:0% +you're out + + + align:start position:0% +you're out +the department chair has to be reviewed + + align:start position:0% +the department chair has to be reviewed + + + align:start position:0% +the department chair has to be reviewed +by the dean + + align:start position:0% +by the dean + + + align:start position:0% +by the dean +every + + align:start position:0% +every + + + align:start position:0% +every +day the department chairs in the sort of + + align:start position:0% +day the department chairs in the sort of + + + align:start position:0% +day the department chairs in the sort of +in between case and i'm certain that and + + align:start position:0% +in between case and i'm certain that and + + + align:start position:0% +in between case and i'm certain that and +then all the places that i have worked + + align:start position:0% +then all the places that i have worked + + + align:start position:0% +then all the places that i have worked +not many but we're talking about nasa + + align:start position:0% +not many but we're talking about nasa + + + align:start position:0% +not many but we're talking about nasa +nuclear regulatory commission + + align:start position:0% +nuclear regulatory commission + + + align:start position:0% +nuclear regulatory commission +uh and the u.s army corps of engineers + + align:start position:0% +uh and the u.s army corps of engineers + + + align:start position:0% +uh and the u.s army corps of engineers +uh there is a + + align:start position:0% +uh there is a + + + align:start position:0% +uh there is a +position of responsibility that i liken + + align:start position:0% +position of responsibility that i liken + + + align:start position:0% +position of responsibility that i liken +to depart to department chairs kind of + + align:start position:0% +to depart to department chairs kind of + + + align:start position:0% +to depart to department chairs kind of +hard to decide + + align:start position:0% +hard to decide + + + align:start position:0% +hard to decide +where they fit + + align:start position:0% +where they fit + + + align:start position:0% +where they fit +okay + + align:start position:0% +okay + + + align:start position:0% +okay +uh so uh the + + align:start position:0% +uh so uh the + + + align:start position:0% +uh so uh the +the other important thing is to remember + + align:start position:0% +the other important thing is to remember + + + align:start position:0% +the other important thing is to remember +that i did say and that is that the + + align:start position:0% +that i did say and that is that the + + + align:start position:0% +that i did say and that is that the +sentiments of the late 60s that brought + + align:start position:0% +sentiments of the late 60s that brought + + + align:start position:0% +sentiments of the late 60s that brought +sts and thus engineering ethics into + + align:start position:0% +sts and thus engineering ethics into + + + align:start position:0% +sts and thus engineering ethics into +being + + align:start position:0% +being + + + align:start position:0% +being +were on the side of nspe and the line + + align:start position:0% +were on the side of nspe and the line + + + align:start position:0% +were on the side of nspe and the line +engineers + + align:start position:0% +engineers + + + align:start position:0% +engineers +because that's where you get mainly the + + align:start position:0% +because that's where you get mainly the + + + align:start position:0% +because that's where you get mainly the +whistleblowers from and all of that + + align:start position:0% +whistleblowers from and all of that + + + align:start position:0% +whistleblowers from and all of that +okay things can change + + align:start position:0% +okay things can change + + + align:start position:0% +okay things can change +things had changed but that's where we + + align:start position:0% +things had changed but that's where we + + + align:start position:0% +things had changed but that's where we +are + + align:start position:0% +are + + + align:start position:0% +are +and the importance of nspe is that + + align:start position:0% +and the importance of nspe is that + + + align:start position:0% +and the importance of nspe is that +most of the codes i think it's fair to + + align:start position:0% +most of the codes i think it's fair to + + + align:start position:0% +most of the codes i think it's fair to +say the line share of the codes + + align:start position:0% +say the line share of the codes + + + align:start position:0% +say the line share of the codes +that are out + + align:start position:0% +that are out + + + align:start position:0% +that are out +that are enforced today + + align:start position:0% +that are enforced today + + + align:start position:0% 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what word is best to +describe + + align:start position:0% +describe + + + align:start position:0% +describe +the relationship between the two + + align:start position:0% +the relationship between the two + + + align:start position:0% +the relationship between the two +uh various from time to time place to + + align:start position:0% +uh various from time to time place to + + + align:start position:0% +uh various from time to time place to +place + + align:start position:0% +place + + + align:start position:0% +place +but you need to be aware that there is a + + align:start position:0% +but you need to be aware that there is a + + + align:start position:0% +but you need to be aware that there is a +line and if you want to be + + align:start position:0% +line and if you want to be + + + align:start position:0% +line and if you want to be +vice president for engineering you're + + align:start position:0% +vice president for engineering you're + + + align:start position:0% +vice president for engineering you're +going to have to go up through the + + align:start position:0% +going to have to go up through the + + + align:start position:0% +going to have to go up through the +management line and you're going to have + + align:start position:0% +management line and you're going to have + + + align:start position:0% +management line and you're going to have +to deal with these people + + align:start position:0% +to deal with these people + + + align:start position:0% +to deal with these people +people who that you were a part of + + align:start position:0% +people who that you were a part of + + + align:start position:0% +people who that you were a part of +right + + align:start position:0% + + + + align:start position:0% + +and they're going to have to deal with + + align:start position:0% +and they're going to have to deal with + + + align:start position:0% +and they're going to have to deal with +you + + align:start position:0% +you + + + align:start position:0% +you +also + + align:start position:0% +also + + + align:start position:0% +also +oh there's another subtlety and that is + + align:start position:0% +oh there's another subtlety and that is + + + align:start position:0% +oh there's another subtlety and that is +that once you decide to go the + + align:start position:0% +that once you decide to go the + + + align:start position:0% +that once you decide to go the +management route + + align:start position:0% + + + + align:start position:0% + +it's very difficult to come back + + align:start position:0% +it's very difficult to come back + + + align:start position:0% +it's very difficult to come back +because you lose those skills + + align:start position:0% +because you lose those skills + + + align:start position:0% +because you lose those skills +it's easy + + align:start position:0% +it's easy + + + align:start position:0% +it's easy +you + + align:start position:0% +you + + + align:start position:0% +you +a person who is not a professional is + + align:start position:0% +a person who is not a professional is + + + align:start position:0% +a person who is not a professional is +going to find what i'm about to say + + align:start position:0% +going to find what i'm about to say + + + align:start position:0% +going to find what i'm about to say +impossible to believe + + align:start position:0% +impossible to believe + + + align:start position:0% +impossible to believe +you do not have + + align:start position:0% +you do not have + + + align:start position:0% +you do not have +to know more or even as much as the + + align:start position:0% +to know more or even as much as the + + + align:start position:0% +to know more or even as much as the +people know that you manage in order to + + align:start position:0% +people know that you manage in order to + + + align:start position:0% +people know that you manage in order to +manage them well + + align:start position:0% + + + + align:start position:0% + +and + + align:start position:0% +and + + + align:start position:0% +and +a good place to learn it + + align:start position:0% +a good place to learn it + + + align:start position:0% +a good place to learn it +is in the army second lieutenant + + align:start position:0% +is in the army second lieutenant + + + align:start position:0% +is in the army second lieutenant +22 years old sergeant 40 years old + + align:start position:0% +22 years old sergeant 40 years old + + + align:start position:0% +22 years old sergeant 40 years old +second two lieutenant doesn't know + + align:start position:0% +second two lieutenant doesn't know + + + align:start position:0% +second two lieutenant doesn't know +one-tenth of what the sergeant knows + + align:start position:0% +one-tenth of what the sergeant knows + + + align:start position:0% +one-tenth of what the sergeant knows +but the lieutenant is not supposed to + + align:start position:0% +but the lieutenant is not supposed to + + + align:start position:0% +but the lieutenant is not supposed to +know + + align:start position:0% +know + + + align:start position:0% +know +the lieutenant is supposed to know when + + align:start position:0% +the lieutenant is supposed to know when + + + align:start position:0% +the lieutenant is supposed to know when +the job is done right and when it's + + align:start position:0% +the job is done right and when it's + + + align:start position:0% +the job is done right and when it's +wrong and when the pastor ordered down + + align:start position:0% +wrong and when the pastor ordered down + + + align:start position:0% +wrong and when the pastor ordered down +from the higher interface + + align:start position:0% +from the higher interface + + + align:start position:0% +from the higher interface +that unit with the higher unit + + align:start position:0% +that unit with the higher unit + + + align:start position:0% +that unit with the higher unit +but the sergeant's supposed to know all + + align:start position:0% +but the sergeant's supposed to know all + + + align:start position:0% +but the sergeant's supposed to know all +this other stuff + + align:start position:0% +this other stuff + + + align:start position:0% +this other stuff +and the lieutenant tells the sergeant + + align:start position:0% +and the lieutenant tells the sergeant + + + align:start position:0% +and the lieutenant tells the sergeant +what to do and the sergeant get the men + + align:start position:0% +what to do and the sergeant get the men + + + align:start position:0% +what to do and the sergeant get the men +order + + align:start position:0% +order + + + align:start position:0% +order +tell them what to do and do all of that + + align:start position:0% +tell them what to do and do all of that + + + align:start position:0% +tell them what to do and do all of that +so + + align:start position:0% +so + + + align:start position:0% +so +um + + align:start position:0% +um + + + align:start position:0% +um +so you have to learn and appreciate that + + align:start position:0% +so you have to learn and appreciate that + + + align:start position:0% +so you have to learn and appreciate that +that's engineering is set up the same + + align:start position:0% +that's engineering is set up the same + + + align:start position:0% +that's engineering is set up the same +way + + align:start position:0% +way + + + align:start position:0% +way +that when that you don't know as much + + align:start position:0% +that when that you don't know as much + + + align:start position:0% +that when that you don't know as much +about putting steel in concrete as the + + align:start position:0% +about putting steel in concrete as the + + + align:start position:0% +about putting steel in concrete as the +steel workers do + + align:start position:0% +steel workers do + + + align:start position:0% +steel workers do +the manager + + align:start position:0% + + + + align:start position:0% + +even if you did know + + align:start position:0% +even if you did know + + + align:start position:0% +even if you did know +right even if you did know + + align:start position:0% +right even if you did know + + + align:start position:0% +right even if you did know +even if you were a steel worker and now + + align:start position:0% +even if you were a steel worker and now + + + align:start position:0% +even if you were a steel worker and now +a manager + + align:start position:0% +a manager + + + align:start position:0% +a manager +a couple years down the line you're + + align:start position:0% +a couple years down the line you're + + + align:start position:0% +a couple years down the line you're +going to + + align:start position:0% +going to + + + align:start position:0% +going to +not be you're going to lose your + + align:start position:0% +not be you're going to lose your + + + align:start position:0% +not be you're going to lose your +competency + + align:start position:0% +competency + + + align:start position:0% +competency +things are going to change + + align:start position:0% +things are going to change + + + align:start position:0% +things are going to change +especially + + align:start position:0% +especially + + + align:start position:0% +especially +so that's another thing you have to do + + align:start position:0% +so that's another thing you have to do + + + align:start position:0% +so that's another thing you have to do +so uh let's see let's see if we can't uh + + align:start position:0% +so uh let's see let's see if we can't uh + + + align:start position:0% +so uh let's see let's see if we can't uh +interrogate this code how is it + + align:start position:0% +interrogate this code how is it + + + align:start position:0% +interrogate this code how is it +organized does it have a preamble does + + align:start position:0% +organized does it have a preamble does + + + align:start position:0% +organized does it have a preamble does +it uh + + align:start position:0% +it uh + + + align:start position:0% +it uh +have sections + + align:start position:0% + + + + align:start position:0% + +all right + + align:start position:0% + + + + align:start position:0% + +in + + align:start position:0% + + + + align:start position:0% + +are divided + + align:start position:0% + + + + align:start position:0% + +let's read the parable + + align:start position:0% +let's read the parable + + + align:start position:0% +let's read the parable +and then let's go through the the + + align:start position:0% +and then let's go through the the + + + align:start position:0% +and then let's go through the the +cannons they are uh how many six or + + align:start position:0% +cannons they are uh how many six or + + + align:start position:0% +cannons they are uh how many six or +seven of + + align:start position:0% +seven of + + + align:start position:0% +seven of +six uh let's go through the cannons and + + align:start position:0% +six uh let's go through the cannons and + + + align:start position:0% +six uh let's go through the cannons and +then let's pick out + + align:start position:0% +then let's pick out + + + align:start position:0% +then let's pick out +any of the other parts that we want to + + align:start position:0% +any of the other parts that we want to + + + align:start position:0% +any of the other parts that we want to +talk about + + align:start position:0% +talk about + + + align:start position:0% +talk about +so somebody read the korean + + align:start position:0% +so somebody read the korean + + + align:start position:0% +so somebody read the korean +please engineering is an important and + + align:start position:0% +please engineering is an important and + + + align:start position:0% +please engineering is an important and +learning profession + + align:start position:0% +learning profession + + + align:start position:0% +learning profession +as members of this profession engineers + + align:start position:0% +as members of this profession engineers + + + align:start position:0% +as members of this profession engineers +are expected to exhibit the highest + + align:start position:0% +are expected to exhibit the highest + + + align:start position:0% +are expected to exhibit the highest +standards of honesty and integrity + + align:start position:0% +standards of honesty and integrity + + + align:start position:0% +standards of honesty and integrity +engineering has a direct and vital + + align:start position:0% +engineering has a direct and vital + + + align:start position:0% +engineering has a direct and vital +impact + + align:start position:0% +impact + + + align:start position:0% +impact +accordingly the services provided by + + align:start position:0% +accordingly the services provided by + + + align:start position:0% +accordingly the services provided by +engineers require honesty impartiality + + align:start position:0% +engineers require honesty impartiality + + + align:start position:0% +engineers require honesty impartiality +fairness and equity and must be + + align:start position:0% +fairness and equity and must be + + + align:start position:0% +fairness and equity and must be +dedicated to the protection of the + + align:start position:0% +dedicated to the protection of the + + + align:start position:0% +dedicated to the protection of the +public health safety and welfare + + align:start position:0% +public health safety and welfare + + + align:start position:0% +public health safety and welfare +engineers must perform under a standard + + align:start position:0% +engineers must perform under a standard + + + align:start position:0% +engineers must perform under a standard +of professional behavior that requires + + align:start position:0% +of professional behavior that requires + + + align:start position:0% +of professional behavior that requires +adherence to the highest principles of + + align:start position:0% +adherence to the highest principles of + + + align:start position:0% +adherence to the highest principles of +ethical conduct + + align:start position:0% +ethical conduct + + + align:start position:0% +ethical conduct +okay so there's a statement of what the + + align:start position:0% +okay so there's a statement of what the + + + align:start position:0% +okay so there's a statement of what the +profession is + + align:start position:0% +profession is + + + align:start position:0% +profession is +subject to debate but that's the + + align:start position:0% +subject to debate but that's the + + + align:start position:0% +subject to debate but that's the +statement that is uh authorized by this + + align:start position:0% +statement that is uh authorized by this + + + align:start position:0% +statement that is uh authorized by this +organization + + align:start position:0% +organization + + + align:start position:0% +organization +all right uh do we have any problems + + align:start position:0% +all right uh do we have any problems + + + align:start position:0% +all right uh do we have any problems +with that statement yeah we got a + + align:start position:0% +with that statement yeah we got a + + + align:start position:0% +with that statement yeah we got a +problem with the statement uh do we + + align:start position:0% +problem with the statement uh do we + + + align:start position:0% +problem with the statement uh do we +think that that + + align:start position:0% +think that that + + + align:start position:0% +think that that +when i say we have problems you come in + + align:start position:0% +when i say we have problems you come in + + + align:start position:0% +when i say we have problems you come in +any way you want but i really want to + + align:start position:0% +any way you want but i really want to + + + align:start position:0% +any way you want but i really want to +know if you think there's anything about + + align:start position:0% +know if you think there's anything about + + + align:start position:0% +know if you think there's anything about +that statement that should not be in a + + align:start position:0% +that statement that should not be in a + + + align:start position:0% +that statement that should not be in a +professional organization's preamble up + + align:start position:0% +professional organization's preamble up + + + align:start position:0% +professional organization's preamble up +to its code of ethics + + align:start position:0% + + + + align:start position:0% + +have they deceived anybody about the + + align:start position:0% +have they deceived anybody about the + + + align:start position:0% +have they deceived anybody about the +greatness of engineering + + align:start position:0% + + + + align:start position:0% + +i either believe or are given the + + align:start position:0% +i either believe or are given the + + + align:start position:0% +i either believe or are given the +opportunity + + align:start position:0% + + + + align:start position:0% + +right that doesn't answer your questions + + align:start position:0% + + + + align:start position:0% + +well it does + + align:start position:0% + + + + align:start position:0% + +is + + align:start position:0% + + + + align:start position:0% + +oh okay i'm sorry + + align:start position:0% +oh okay i'm sorry + + + align:start position:0% +oh okay i'm sorry +is it rubbing up against this pen i + + align:start position:0% +is it rubbing up against this pen i + + + align:start position:0% +is it rubbing up against this pen i +think + + align:start position:0% + + + + align:start position:0% + +[Laughter] + + align:start position:0% +[Laughter] + + + align:start position:0% +[Laughter] +okay thank you + + align:start position:0% + + + + align:start position:0% + +yeah if there's anything wrong with it + + align:start position:0% +yeah if there's anything wrong with it + + + align:start position:0% +yeah if there's anything wrong with it +it might be too idealistic and that it's + + align:start position:0% +it might be too idealistic and that it's + + + align:start position:0% +it might be too idealistic and that it's +all right to shoot after + + align:start position:0% +all right to shoot after + + + align:start position:0% +all right to shoot after +as a goal + + align:start position:0% +as a goal + + + align:start position:0% +as a goal +yeah that's good i think that's a good + + align:start position:0% +yeah that's good i think that's a good + + + align:start position:0% +yeah that's good i think that's a good +way to think about it + + align:start position:0% +way to think about it + + + align:start position:0% +way to think about it +uh as to whether or not all the + + align:start position:0% +uh as to whether or not all the + + + align:start position:0% +uh as to whether or not all the +engineers buy into it + + align:start position:0% +engineers buy into it + + + align:start position:0% +engineers buy into it +well the question is what is their um + + align:start position:0% +well the question is what is their um + + + align:start position:0% +well the question is what is their um +decision-making method i don't think + + align:start position:0% +decision-making method i don't think + + + align:start position:0% +decision-making method i don't think +that they use + + align:start position:0% +that they use + + + align:start position:0% +that they use +a plebiscite + + align:start position:0% + + + + align:start position:0% + +uh where you go out and and take the + + align:start position:0% +uh where you go out and and take the + + + align:start position:0% +uh where you go out and and take the +majority of everybody + + align:start position:0% +majority of everybody + + + align:start position:0% +majority of everybody +no they get a committee + + align:start position:0% + + + + align:start position:0% + +no + + align:start position:0% + + + + align:start position:0% + +[Laughter] + + align:start position:0% + + + + align:start position:0% + +yes + + align:start position:0% +yes + + + align:start position:0% +yes +yes + + align:start position:0% + + + + align:start position:0% + +yeah + + align:start position:0% +yeah + + + align:start position:0% +yeah +well there's another thing to a way to + + align:start position:0% +well there's another thing to a way to + + + align:start position:0% +well there's another thing to a way to +think about it uh they've got it + + align:start position:0% +think about it uh they've got it + + + align:start position:0% +think about it uh they've got it +published + + align:start position:0% +published + + + align:start position:0% +published +and if you don't like it you don't have + + align:start position:0% +and if you don't like it you don't have + + + align:start position:0% +and if you don't like it you don't have +to join nspe that's another way to think + + align:start position:0% +to join nspe that's another way to think + + + align:start position:0% +to join nspe that's another way to think +about it doesn't mean that you agree + + align:start position:0% +about it doesn't mean that you agree + + + align:start position:0% +about it doesn't mean that you agree +with it but if you still want to join + + align:start position:0% +with it but if you still want to join + + + align:start position:0% +with it but if you still want to join +nspe you have to take responsibility + + align:start position:0% +nspe you have to take responsibility + + + align:start position:0% +nspe you have to take responsibility +for that statement some way or another + + align:start position:0% +for that statement some way or another + + + align:start position:0% +for that statement some way or another +you did it with your eyes open it's + + align:start position:0% +you did it with your eyes open it's + + + align:start position:0% +you did it with your eyes open it's +published + + align:start position:0% + + + + align:start position:0% + +yeah + + align:start position:0% + + + + align:start position:0% + +none of us + + align:start position:0% + + + + align:start position:0% + +well + + align:start position:0% +well + + + align:start position:0% +well +the price you pay for that or not the + + align:start position:0% +the price you pay for that or not the + + + align:start position:0% +the price you pay for that or not the +price but a price that you pay for that + + align:start position:0% +price but a price that you pay for that + + + align:start position:0% +price but a price that you pay for that +is if you go to court the judge is going + + align:start position:0% +is if you go to court the judge is going + + + align:start position:0% +is if you go to court the judge is going +to take that position + + align:start position:0% +to take that position + + + align:start position:0% +to take that position +literally + + align:start position:0% + + + + align:start position:0% + +the judge is going to say here it is + + align:start position:0% +the judge is going to say here it is + + + align:start position:0% +the judge is going to say here it is +it's published i got a copy of it + + align:start position:0% +it's published i got a copy of it + + + align:start position:0% +it's published i got a copy of it +everybody's got a copy of it + + align:start position:0% +everybody's got a copy of it + + + align:start position:0% +everybody's got a copy of it +over here i see where your application + + align:start position:0% +over here i see where your application + + + align:start position:0% +over here i see where your application +you asked to be a member nobody came + + align:start position:0% +you asked to be a member nobody came + + + align:start position:0% +you asked to be a member nobody came +down and said you've got to be one or + + align:start position:0% +down and said you've got to be one or + + + align:start position:0% +down and said you've got to be one or +else we'll fire you nobody said that + + align:start position:0% +else we'll fire you nobody said that + + + align:start position:0% +else we'll fire you nobody said that +you're paid your dues every year for the + + align:start position:0% +you're paid your dues every year for the + + + align:start position:0% +you're paid your dues every year for the +last 10 years you had time to change + + align:start position:0% +last 10 years you had time to change + + + align:start position:0% +last 10 years you had time to change +your mind + + align:start position:0% +your mind + + + align:start position:0% +your mind +after you got experience but no you kept + + align:start position:0% +after you got experience but no you kept + + + align:start position:0% +after you got experience but no you kept +your mouth shut you got to pay the price + + align:start position:0% +your mouth shut you got to pay the price + + + align:start position:0% +your mouth shut you got to pay the price +you gotta have to live up to that + + align:start position:0% +you gotta have to live up to that + + + align:start position:0% +you gotta have to live up to that +so that's another way + + align:start position:0% +so that's another way + + + align:start position:0% +so that's another way +to think about this whole thing so + + align:start position:0% + + + + align:start position:0% + +yeah they decide to subscribe to it + + align:start position:0% +yeah they decide to subscribe to it + + + align:start position:0% +yeah they decide to subscribe to it +and so therefore if they come before + + align:start position:0% +and so therefore if they come before + + + align:start position:0% +and so therefore if they come before +let's say + + align:start position:0% +let's say + + + align:start position:0% +let's say +a community group or high school + + align:start position:0% +a community group or high school + + + align:start position:0% +a community group or high school +uh pta + + align:start position:0% +uh pta + + + align:start position:0% +uh pta +and they say well what is what do you + + align:start position:0% +and they say well what is what do you + + + align:start position:0% +and they say well what is what do you +stand for what is engineering and you + + align:start position:0% +stand for what is engineering and you + + + align:start position:0% +stand for what is engineering and you +look like a liar if you don't say + + align:start position:0% +look like a liar if you don't say + + + align:start position:0% +look like a liar if you don't say +something like this + + align:start position:0% +something like this + + + align:start position:0% +something like this +so because you belong you ask to be lost + + align:start position:0% +so because you belong you ask to be lost + + + align:start position:0% +so because you belong you ask to be lost +free country you don't have to belong + + align:start position:0% +free country you don't have to belong + + + align:start position:0% +free country you don't have to belong +all right so there is the goal + + align:start position:0% +all right so there is the goal + + + align:start position:0% +all right so there is the goal +uh + + align:start position:0% +uh + + + align:start position:0% +uh +now the fundamental cannons + + align:start position:0% +now the fundamental cannons + + + align:start position:0% +now the fundamental cannons +um + + align:start position:0% +um + + + align:start position:0% +um +are more or less + + align:start position:0% +are more or less + + + align:start position:0% +are more or less +that's the that's the this the the + + align:start position:0% +that's the that's the this the the + + + align:start position:0% +that's the that's the this the the +preamble is sort of the end + + align:start position:0% +preamble is sort of the end + + + align:start position:0% +preamble is sort of the end +and the fundamental cannons are the + + align:start position:0% +and the fundamental cannons are the + + + align:start position:0% +and the fundamental cannons are the +means + + align:start position:0% +means + + + align:start position:0% +means +uh laid out in general terms + + align:start position:0% +uh laid out in general terms + + + align:start position:0% +uh laid out in general terms +and we get specifics later + + align:start position:0% +and we get specifics later + + + align:start position:0% +and we get specifics later +and the idea with the specifics is that + + align:start position:0% +and the idea with the specifics is that + + + align:start position:0% +and the idea with the specifics is that +when we uh + + align:start position:0% +when we uh + + + align:start position:0% +when we uh +review the code + + align:start position:0% +review the code + + + align:start position:0% +review the code +and makes decide to make changes or make + + align:start position:0% +and makes decide to make changes or make + + + align:start position:0% +and makes decide to make changes or make +additions + + align:start position:0% +additions + + + align:start position:0% +additions +if we've done things right the preamble + + align:start position:0% +if we've done things right the preamble + + + align:start position:0% +if we've done things right the preamble +and the fundamental cannons remain the + + align:start position:0% +and the fundamental cannons remain the + + + align:start position:0% +and the fundamental cannons remain the +same we only change the rest of + + align:start position:0% +same we only change the rest of + + + align:start position:0% +same we only change the rest of +the details + + align:start position:0% +the details + + + align:start position:0% +the details +in other words there's something that's + + align:start position:0% +in other words there's something that's + + + align:start position:0% +in other words there's something that's +about our organization + + align:start position:0% +about our organization + + + align:start position:0% +about our organization +one would say + + align:start position:0% +one would say + + + align:start position:0% +one would say +who is a who is a member one would say + + align:start position:0% +who is a who is a member one would say + + + align:start position:0% +who is a who is a member one would say +that has lasting value + + align:start position:0% +that has lasting value + + + align:start position:0% +that has lasting value +and the preamble and the fundamental + + align:start position:0% +and the preamble and the fundamental + + + align:start position:0% +and the preamble and the fundamental +canons of you if you're doing things + + align:start position:0% +canons of you if you're doing things + + + align:start position:0% +canons of you if you're doing things +right have lasting value + + align:start position:0% +right have lasting value + + + align:start position:0% +right have lasting value +and that the details about how you carry + + align:start position:0% +and that the details about how you carry + + + align:start position:0% +and that the details about how you carry +it out + + align:start position:0% + + + + align:start position:0% + +uh + + align:start position:0% +uh + + + align:start position:0% +uh +may change from time to time + + align:start position:0% +may change from time to time + + + align:start position:0% +may change from time to time +and another way to think about it is + + align:start position:0% +and another way to think about it is + + + align:start position:0% +and another way to think about it is +that the fundamental cannons + + align:start position:0% +that the fundamental cannons + + + align:start position:0% +that the fundamental cannons +uh lay down your strategy + + align:start position:0% +uh lay down your strategy + + + align:start position:0% +uh lay down your strategy +and the rules of pr practice and the + + align:start position:0% +and the rules of pr practice and the + + + align:start position:0% +and the rules of pr practice and the +other the last part are your tactics + + align:start position:0% + + + + align:start position:0% + +see it all fits right + + align:start position:0% + + + + align:start position:0% + +remember the basketball metaphor + + align:start position:0% +remember the basketball metaphor + + + align:start position:0% +remember the basketball metaphor +did we do that in this class yeah we did + + align:start position:0% +did we do that in this class yeah we did + + + align:start position:0% +did we do that in this class yeah we did +it + + align:start position:0% +it + + + align:start position:0% +it +big guys can go for the yeah + + align:start position:0% +big guys can go for the yeah + + + align:start position:0% +big guys can go for the yeah +right so the strategy + + align:start position:0% +right so the strategy + + + align:start position:0% +right so the strategy +for + + align:start position:0% +for + + + align:start position:0% +for +uh achieving this goal is laid down in + + align:start position:0% +uh achieving this goal is laid down in + + + align:start position:0% +uh achieving this goal is laid down in +your four the six fundamental cannons + + align:start position:0% +your four the six fundamental cannons + + + align:start position:0% +your four the six fundamental cannons +and your tactics are laid down in the + + align:start position:0% +and your tactics are laid down in the + + + align:start position:0% +and your tactics are laid down in the +rest of it + + align:start position:0% +rest of it + + + align:start position:0% +rest of it +uh now uh + + align:start position:0% +uh now uh + + + align:start position:0% +uh now uh +let's go through these canons it's only + + align:start position:0% +let's go through these canons it's only + + + align:start position:0% +let's go through these canons it's only +six seven let's go through them one by + + align:start position:0% +six seven let's go through them one by + + + align:start position:0% +six seven let's go through them one by +one because as you said we're going to + + align:start position:0% +one because as you said we're going to + + + align:start position:0% +one because as you said we're going to +find them elsewhere + + align:start position:0% +find them elsewhere + + + align:start position:0% +find them elsewhere +what's the first one say + + align:start position:0% + + + + align:start position:0% + +now whatever you do in this life for the + + align:start position:0% +now whatever you do in this life for the + + + align:start position:0% +now whatever you do in this life for the +asterisk beside that statement + + align:start position:0% +asterisk beside that statement + + + align:start position:0% +asterisk beside that statement +because that is + + align:start position:0% +because that is + + + align:start position:0% +because that is +the fundamental point of controversy + + align:start position:0% +the fundamental point of controversy + + + align:start position:0% +the fundamental point of controversy +over engineering ethics + + align:start position:0% +over engineering ethics + + + align:start position:0% +over engineering ethics +in the 20 + + align:start position:0% +in the 20 + + + align:start position:0% +in the 20 +in the 20th century + + align:start position:0% +in the 20th century + + + align:start position:0% +in the 20th century +it is number one + + align:start position:0% +it is number one + + + align:start position:0% +it is number one +i do not stand alone when + + align:start position:0% +i do not stand alone when + + + align:start position:0% +i do not stand alone when +using that superlative + + align:start position:0% +using that superlative + + + align:start position:0% +using that superlative +it is the + + align:start position:0% +it is the + + + align:start position:0% +it is the +most debated highest debated issue + + align:start position:0% +most debated highest debated issue + + + align:start position:0% +most debated highest debated issue +and the nspe was the first one to come + + align:start position:0% +and the nspe was the first one to come + + + align:start position:0% +and the nspe was the first one to come +out early and say + + align:start position:0% +out early and say + + + align:start position:0% +out early and say +that + + align:start position:0% +that + + + align:start position:0% +that +responsibility for the public is more + + align:start position:0% +responsibility for the public is more + + + align:start position:0% +responsibility for the public is more +important + + align:start position:0% +important + + + align:start position:0% +important +than responsibility for the client and + + align:start position:0% +than responsibility for the client and + + + align:start position:0% +than responsibility for the client and +the employee they were the first to jump + + align:start position:0% +the employee they were the first to jump + + + align:start position:0% +the employee they were the first to jump +out and say that + + align:start position:0% +out and say that + + + align:start position:0% +out and say that +and uh that and + + align:start position:0% +and uh that and + + + align:start position:0% +and uh that and +and that + + align:start position:0% +and that + + + align:start position:0% +and that +you can see that if an organization + + align:start position:0% +you can see that if an organization + + + align:start position:0% +you can see that if an organization +is controlled by managers + + align:start position:0% + + + + align:start position:0% + +they were going to have problems with + + align:start position:0% +they were going to have problems with + + + align:start position:0% +they were going to have problems with +that state + + align:start position:0% + + + + align:start position:0% + +and the typical uh response from a + + align:start position:0% +and the typical uh response from a + + + align:start position:0% +and the typical uh response from a +management point of view is + + align:start position:0% +management point of view is + + + align:start position:0% +management point of view is +that + + align:start position:0% +that + + + align:start position:0% +that +there are competing interests that are + + align:start position:0% +there are competing interests that are + + + align:start position:0% +there are competing interests that are +in that an engineer has to satisfy + + align:start position:0% + + + + align:start position:0% + +one is the public one is the client and + + align:start position:0% +one is the public one is the client and + + + align:start position:0% +one is the public one is the client and +the other one's the employee + + align:start position:0% + + + + align:start position:0% + +and nspe comes right out and uses this + + align:start position:0% +and nspe comes right out and uses this + + + align:start position:0% +and nspe comes right out and uses this +word paramount + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and by the way arnie veselan's last book + + align:start position:0% +and by the way arnie veselan's last book + + + align:start position:0% +and by the way arnie veselan's last book +latest it's not he got a new one i just + + align:start position:0% +latest it's not he got a new one i just + + + align:start position:0% +latest it's not he got a new one i just +heard + + align:start position:0% +heard + + + align:start position:0% +heard +but let's put let's say it this way his + + align:start position:0% +but let's put let's say it this way his + + + align:start position:0% +but let's put let's say it this way his +latest book is entitled hold paramount + + align:start position:0% + + + + align:start position:0% + +okay so that means that now you have + + align:start position:0% +okay so that means that now you have + + + align:start position:0% +okay so that means that now you have +what is called a super principle + + align:start position:0% +what is called a super principle + + + align:start position:0% +what is called a super principle +that principle number one is more + + align:start position:0% +that principle number one is more + + + align:start position:0% +that principle number one is more +overriding over the next five + + align:start position:0% + + + + align:start position:0% + +and most of the code and most of the + + align:start position:0% +and most of the code and most of the + + + align:start position:0% +and most of the code and most of the +and certainly the one i was in with the + + align:start position:0% +and certainly the one i was in with the + + + align:start position:0% +and certainly the one i was in with the +aaes and when i was in the one with the + + align:start position:0% +aaes and when i was in the one with the + + + align:start position:0% +aaes and when i was in the one with the +aes i was very much aware of what the + + align:start position:0% +aes i was very much aware of what the + + + align:start position:0% +aes i was very much aware of what the +other ones were doing + + align:start position:0% +other ones were doing + + + align:start position:0% +other ones were doing +because we would have we would call it + + align:start position:0% +because we would have we would call it + + + align:start position:0% +because we would have we would call it +all that kind of stuff + + align:start position:0% +all that kind of stuff + + + align:start position:0% +all that kind of stuff +i had i had to go out and give all of + + align:start position:0% +i had i had to go out and give all of + + + align:start position:0% +i had i had to go out and give all of +these speeches on behalf of my committee + + align:start position:0% + + + + align:start position:0% + +and + + align:start position:0% +and + + + align:start position:0% +and +um + + align:start position:0% +um + + + align:start position:0% +um +we all had the same problem + + align:start position:0% +we all had the same problem + + + align:start position:0% +we all had the same problem +and uh + + align:start position:0% +and uh + + + align:start position:0% +and uh +we did we worked at aaes when we get to + + align:start position:0% +we did we worked at aaes when we get to + + + align:start position:0% +we did we worked at aaes when we get to +it i just have a burning issue to say + + align:start position:0% +it i just have a burning issue to say + + + align:start position:0% +it i just have a burning issue to say +this right now we worked on that that + + align:start position:0% +this right now we worked on that that + + + align:start position:0% +this right now we worked on that that +thing for + + align:start position:0% + + + + align:start position:0% + +must have been about five years + + align:start position:0% + + + + align:start position:0% + +and uh i was on the committee the last + + align:start position:0% +and uh i was on the committee the last + + + align:start position:0% +and uh i was on the committee the last +maybe + + align:start position:0% +maybe + + + align:start position:0% +maybe +three years of it and i was chair of it + + align:start position:0% +three years of it and i was chair of it + + + align:start position:0% +three years of it and i was chair of it +the last + + align:start position:0% +the last + + + align:start position:0% +the last +two years of it + + align:start position:0% +two years of it + + + align:start position:0% +two years of it +and we did not get a code of ethics + + align:start position:0% +and we did not get a code of ethics + + + align:start position:0% +and we did not get a code of ethics +until + + align:start position:0% +until + + + align:start position:0% +until +we passed this paramounty rule and then + + align:start position:0% +we passed this paramounty rule and then + + + align:start position:0% +we passed this paramounty rule and then +we had one + + align:start position:0% +we had one + + + align:start position:0% +we had one +we were not the committee was not + + align:start position:0% +we were not the committee was not + + + align:start position:0% +we were not the committee was not +willing to submit anything + + align:start position:0% +willing to submit anything + + + align:start position:0% +willing to submit anything +because + + align:start position:0% +because + + + align:start position:0% +because +well + + align:start position:0% +well + + + align:start position:0% +well +until we resolved the issue among + + align:start position:0% +until we resolved the issue among + + + align:start position:0% +until we resolved the issue among +ourselves + + align:start position:0% +ourselves + + + align:start position:0% +ourselves +it was fought that hard hard + + align:start position:0% + + + + align:start position:0% + +and i'll tell you what happened i'll + + align:start position:0% +and i'll tell you what happened i'll + + + align:start position:0% +and i'll tell you what happened i'll +tell you what happened there this is + + align:start position:0% +tell you what happened there this is + + + align:start position:0% +tell you what happened there this is +open i'll call names + + align:start position:0% +open i'll call names + + + align:start position:0% +open i'll call names +uh there was a guy who was a manager + + align:start position:0% +uh there was a guy who was a manager + + + align:start position:0% +uh there was a guy who was a manager +named bill middleton + + align:start position:0% +named bill middleton + + + align:start position:0% +named bill middleton +was on the committee and + + align:start position:0% +was on the committee and + + + align:start position:0% +was on the committee and +he was a very thoughtful person + + align:start position:0% +he was a very thoughtful person + + + align:start position:0% +he was a very thoughtful person +and he was very strong on the side of + + align:start position:0% +and he was very strong on the side of + + + align:start position:0% +and he was very strong on the side of +balancing those that's the term + + align:start position:0% +balancing those that's the term + + + align:start position:0% +balancing those that's the term +balancing competing interests and for a + + align:start position:0% +balancing competing interests and for a + + + align:start position:0% +balancing competing interests and for a +long time + + align:start position:0% +long time + + + align:start position:0% +long time +and then i don't know who said it wasn't + + align:start position:0% +and then i don't know who said it wasn't + + + align:start position:0% +and then i don't know who said it wasn't +me but somebody said something in there + + align:start position:0% +me but somebody said something in there + + + align:start position:0% +me but somebody said something in there +that worked on his heart i don't know + + align:start position:0% +that worked on his heart i don't know + + + align:start position:0% +that worked on his heart i don't know +what it was + + align:start position:0% +what it was + + + align:start position:0% +what it was +but he got on the train going back + + align:start position:0% +but he got on the train going back + + + align:start position:0% +but he got on the train going back +home to philadelphia and he wrote up + + align:start position:0% +home to philadelphia and he wrote up + + + align:start position:0% +home to philadelphia and he wrote up +what he thought should be + + align:start position:0% +what he thought should be + + + align:start position:0% +what he thought should be +our fundamental canons and he put + + align:start position:0% +our fundamental canons and he put + + + align:start position:0% +our fundamental canons and he put +a paramouncy rule in there he did i + + align:start position:0% +a paramouncy rule in there he did i + + + align:start position:0% +a paramouncy rule in there he did i +don't think he used the word paramount + + align:start position:0% +don't think he used the word paramount + + + align:start position:0% +don't think he used the word paramount +but he but he made it more paramount + + align:start position:0% +but he but he made it more paramount + + + align:start position:0% +but he but he made it more paramount +and he + + align:start position:0% +and he + + + align:start position:0% +and he +sent it back to me and said he got it to + + align:start position:0% +sent it back to me and said he got it to + + + align:start position:0% +sent it back to me and said he got it to +him on the train + + align:start position:0% +him on the train + + + align:start position:0% +him on the train +when i got it + + align:start position:0% +when i got it + + + align:start position:0% +when i got it +i put it in the code + + align:start position:0% +i put it in the code + + + align:start position:0% +i put it in the code +and i called the president of the + + align:start position:0% +and i called the president of the + + + align:start position:0% +and i called the president of the +organization i said we finished the cup + + align:start position:0% + + + + align:start position:0% + +i said i have to tell you + + align:start position:0% +i said i have to tell you + + + align:start position:0% +i said i have to tell you +i don't have the the vote in writing + + align:start position:0% +i don't have the the vote in writing + + + align:start position:0% +i don't have the the vote in writing +he said we've been waiting on this thing + + align:start position:0% +he said we've been waiting on this thing + + + align:start position:0% +he said we've been waiting on this thing +for six years he said well you take + + align:start position:0% +for six years he said well you take + + + align:start position:0% +for six years he said well you take +responsibility for it i said i will i + + align:start position:0% +responsibility for it i said i will i + + + align:start position:0% +responsibility for it i said i will i +sent it up man we had it nobody objected + + align:start position:0% +sent it up man we had it nobody objected + + + align:start position:0% +sent it up man we had it nobody objected +once it went in because it came out of + + align:start position:0% +once it went in because it came out of + + + align:start position:0% +once it went in because it came out of +this man's + + align:start position:0% +this man's + + + align:start position:0% +this man's +heart he found some correlation between + + align:start position:0% +heart he found some correlation between + + + align:start position:0% +heart he found some correlation between +what was in his unconscious and his + + align:start position:0% +what was in his unconscious and his + + + align:start position:0% +what was in his unconscious and his +conscience and i said what + + align:start position:0% +conscience and i said what + + + align:start position:0% +conscience and i said what +when that thing comes out everybody's + + align:start position:0% +when that thing comes out everybody's + + + align:start position:0% +when that thing comes out everybody's +going to buy it or + + align:start position:0% +going to buy it or + + + align:start position:0% +going to buy it or +a person who doesn't buy it is not going + + align:start position:0% +a person who doesn't buy it is not going + + + align:start position:0% +a person who doesn't buy it is not going +to fight against it + + align:start position:0% + + + + align:start position:0% + +right + + align:start position:0% + + + + align:start position:0% + +yes + + align:start position:0% +yes + + + align:start position:0% +yes +and it hurts business + + align:start position:0% + + + + align:start position:0% + +uh and um + + align:start position:0% +uh and um + + + align:start position:0% +uh and um +people argue + + align:start position:0% +people argue + + + align:start position:0% +people argue +okay uh + + align:start position:0% +okay uh + + + align:start position:0% +okay uh +and um + + align:start position:0% + + + + align:start position:0% + +and that and then you then you get into + + align:start position:0% +and that and then you then you get into + + + align:start position:0% +and that and then you then you get into +this whole thing about gray areas and + + align:start position:0% +this whole thing about gray areas and + + + align:start position:0% +this whole thing about gray areas and +complexity + + align:start position:0% +complexity + + + align:start position:0% +complexity +and most of the issues weren't gray and + + align:start position:0% +and most of the issues weren't gray and + + + align:start position:0% +and most of the issues weren't gray and +they weren't complex + + align:start position:0% +they weren't complex + + + align:start position:0% +they weren't complex +but + + align:start position:0% + + + + align:start position:0% + +they really wanted to wanted a + + align:start position:0% +they really wanted to wanted a + + + align:start position:0% +they really wanted to wanted a +profession + + align:start position:0% +profession + + + align:start position:0% +profession +uh + + align:start position:0% +uh + + + align:start position:0% +uh +in which + + align:start position:0% +in which + + + align:start position:0% +in which +every member + + align:start position:0% +every member + + + align:start position:0% +every member +felt a deep sense of loyalty + + align:start position:0% + + + + align:start position:0% + +to whoever was putting the paycheck on + + align:start position:0% +to whoever was putting the paycheck on + + + align:start position:0% +to whoever was putting the paycheck on +the table + + align:start position:0% + + + + align:start position:0% + +right + + align:start position:0% +right + + + align:start position:0% +right +right + + align:start position:0% +right + + + align:start position:0% +right +thought that you could not that that + + align:start position:0% +thought that you could not that that + + + align:start position:0% +thought that you could not that that +that the profession would break down + + align:start position:0% +that the profession would break down + + + align:start position:0% +that the profession would break down +because people would not be loyal + + align:start position:0% +because people would not be loyal + + + align:start position:0% +because people would not be loyal +to the ones they worked for + + align:start position:0% + + + + align:start position:0% + +right there was this question is the way + + align:start position:0% +right there was this question is the way + + + align:start position:0% +right there was this question is the way +not you should serve the public or + + align:start position:0% +not you should serve the public or + + + align:start position:0% +not you should serve the public or +whether it was somebody else's problem + + align:start position:0% +whether it was somebody else's problem + + + align:start position:0% +whether it was somebody else's problem +to serve the public + + align:start position:0% +to serve the public + + + align:start position:0% +to serve the public +or whether you just needed to balance + + align:start position:0% +or whether you just needed to balance + + + align:start position:0% +or whether you just needed to balance +quote-unquote these competing interests + + align:start position:0% +quote-unquote these competing interests + + + align:start position:0% +quote-unquote these competing interests +and + + align:start position:0% +and + + + align:start position:0% +and +my position on there when it came to the + + align:start position:0% +my position on there when it came to the + + + align:start position:0% +my position on there when it came to the +word balance is you got to have a rule + + align:start position:0% +word balance is you got to have a rule + + + align:start position:0% +word balance is you got to have a rule +for what establishes a balance + + align:start position:0% +for what establishes a balance + + + align:start position:0% +for what establishes a balance +all right what is that rule then nobody + + align:start position:0% +all right what is that rule then nobody + + + align:start position:0% +all right what is that rule then nobody +could give me the rule because that goes + + align:start position:0% +could give me the rule because that goes + + + align:start position:0% +could give me the rule because that goes +back to a paramount c + + align:start position:0% +back to a paramount c + + + align:start position:0% +back to a paramount c +something got to be paramount + + align:start position:0% +something got to be paramount + + + align:start position:0% +something got to be paramount +so if you use that word rule what do you + + align:start position:0% +so if you use that word rule what do you + + + align:start position:0% +so if you use that word rule what do you +mean by balance what constitutes a + + align:start position:0% +mean by balance what constitutes a + + + align:start position:0% +mean by balance what constitutes a +balance + + align:start position:0% + + + + align:start position:0% + +well that confused the issue for + + align:start position:0% +well that confused the issue for + + + align:start position:0% +well that confused the issue for +everybody enough + + align:start position:0% +everybody enough + + + align:start position:0% +everybody enough +for us to start thinking about + + align:start position:0% + + + + align:start position:0% + +paramount clause + + align:start position:0% + + + + align:start position:0% + +yeah + + align:start position:0% +yeah + + + align:start position:0% +yeah +because they don't use the word + + align:start position:0% +because they don't use the word + + + align:start position:0% +because they don't use the word +paramount right + + align:start position:0% +paramount right + + + align:start position:0% +paramount right +the first + + align:start position:0% +the first + + + align:start position:0% +the first +their first canon says + + align:start position:0% +their first canon says + + + align:start position:0% +their first canon says +to accept responsibility and making + + align:start position:0% +to accept responsibility and making + + + align:start position:0% +to accept responsibility and making +engineering decisions consistent with + + align:start position:0% +engineering decisions consistent with + + + align:start position:0% +engineering decisions consistent with +the safety health and welfare of the + + align:start position:0% +the safety health and welfare of the + + + align:start position:0% +the safety health and welfare of the +public + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +is that an alternative is that an + + align:start position:0% +is that an alternative is that an + + + align:start position:0% +is that an alternative is that an +alternative that you all were + + align:start position:0% +alternative that you all were + + + align:start position:0% +alternative that you all were +considering + + align:start position:0% +considering + + + align:start position:0% +considering +aaes something like that + + align:start position:0% +aaes something like that + + + align:start position:0% +aaes something like that +no + + align:start position:0% +no + + + align:start position:0% +no +uh + + align:start position:0% +uh + + + align:start position:0% +uh +yeah tripoli um well let's say a few + + align:start position:0% +yeah tripoli um well let's say a few + + + align:start position:0% +yeah tripoli um well let's say a few +things about the ieee first of all + + align:start position:0% +things about the ieee first of all + + + align:start position:0% +things about the ieee first of all +what they had to say back in those days + + align:start position:0% +what they had to say back in those days + + + align:start position:0% +what they had to say back in those days +was very important because they were the + + align:start position:0% +was very important because they were the + + + align:start position:0% +was very important because they were the +largest + + align:start position:0% +largest + + + align:start position:0% +largest +engineering professional organization + + align:start position:0% +engineering professional organization + + + align:start position:0% +engineering professional organization +and secondly they were the largest + + align:start position:0% +and secondly they were the largest + + + align:start position:0% +and secondly they were the largest +partly because + + align:start position:0% +partly because + + + align:start position:0% +partly because +in those in those days the electrical + + align:start position:0% +in those in those days the electrical + + + align:start position:0% +in those in those days the electrical +engineering departments in colleges were + + align:start position:0% +engineering departments in colleges were + + + align:start position:0% +engineering departments in colleges were +the largest + + align:start position:0% +the largest + + + align:start position:0% +the largest +most of the students were in most of the + + align:start position:0% +most of the students were in most of the + + + align:start position:0% +most of the students were in most of the +jobs were in electrical engineering now + + align:start position:0% +jobs were in electrical engineering now + + + align:start position:0% +jobs were in electrical engineering now +that's sort of shifted to computer + + align:start position:0% +that's sort of shifted to computer + + + align:start position:0% +that's sort of shifted to computer +science i believe + + align:start position:0% +science i believe + + + align:start position:0% +science i believe +computer engineering and computer + + align:start position:0% +computer engineering and computer + + + align:start position:0% +computer engineering and computer +science + + align:start position:0% +science + + + align:start position:0% +science +but electrical was the biggest one + + align:start position:0% +but electrical was the biggest one + + + align:start position:0% +but electrical was the biggest one +and + + align:start position:0% +and + + + align:start position:0% +and +lastly + + align:start position:0% +lastly + + + align:start position:0% +lastly +ieee was an international organization + + align:start position:0% + + + + align:start position:0% + +it wasn't the americans + + align:start position:0% +it wasn't the americans + + + align:start position:0% +it wasn't the americans +so they had to be concerned about + + align:start position:0% +so they had to be concerned about + + + align:start position:0% +so they had to be concerned about +international concerns + + align:start position:0% + + + + align:start position:0% + +and + + align:start position:0% +and + + + align:start position:0% +and +all of that weighed in with them + + align:start position:0% + + + + align:start position:0% + +so it looked for a while as though ieee + + align:start position:0% +so it looked for a while as though ieee + + + align:start position:0% +so it looked for a while as though ieee +was going to + + align:start position:0% +was going to + + + align:start position:0% +was going to +control is not the right word dominate + + align:start position:0% +control is not the right word dominate + + + align:start position:0% +control is not the right word dominate +is the right word dominate everybody + + align:start position:0% +is the right word dominate everybody + + + align:start position:0% +is the right word dominate everybody +else + + align:start position:0% + + + + align:start position:0% + +and uh it didn't work + + align:start position:0% +and uh it didn't work + + + align:start position:0% +and uh it didn't work +so ieee has has stood by + + align:start position:0% +so ieee has has stood by + + + align:start position:0% +so ieee has has stood by +what they wrote all of these years and + + align:start position:0% +what they wrote all of these years and + + + align:start position:0% +what they wrote all of these years and +they are just + + align:start position:0% +they are just + + + align:start position:0% +they are just +separate from most from the rest + + align:start position:0% +separate from most from the rest + + + align:start position:0% +separate from most from the rest +yeah + + align:start position:0% + + + + align:start position:0% + +to accept responsibility in making + + align:start position:0% +to accept responsibility in making + + + align:start position:0% +to accept responsibility in making +decisions consistent with the public + + align:start position:0% +decisions consistent with the public + + + align:start position:0% +decisions consistent with the public +safety + + align:start position:0% +safety + + + align:start position:0% +safety +is so different than saying + + align:start position:0% +is so different than saying + + + align:start position:0% +is so different than saying +like hold paramount + + align:start position:0% +like hold paramount + + + align:start position:0% +like hold paramount +exactly does it mean to accept + + align:start position:0% +exactly does it mean to accept + + + align:start position:0% +exactly does it mean to accept +responsibility does that mean you can + + align:start position:0% +responsibility does that mean you can + + + align:start position:0% +responsibility does that mean you can +still make a bad decision + + align:start position:0% + + + + align:start position:0% + +yeah it uh + + align:start position:0% +yeah it uh + + + align:start position:0% +yeah it uh +well it there's one thing that is good + + align:start position:0% +well it there's one thing that is good + + + align:start position:0% +well it there's one thing that is good +about it uh that + + align:start position:0% +about it uh that + + + align:start position:0% +about it uh that +that i take a lesson from + + align:start position:0% +that i take a lesson from + + + align:start position:0% +that i take a lesson from +uh but i don't and that is that it + + align:start position:0% +uh but i don't and that is that it + + + align:start position:0% +uh but i don't and that is that it +presupposes that you can do engineering + + align:start position:0% + + + + align:start position:0% + +uh and not have to sacrifice + + align:start position:0% +uh and not have to sacrifice + + + align:start position:0% +uh and not have to sacrifice +your employer or client to do the right + + align:start position:0% +your employer or client to do the right + + + align:start position:0% +your employer or client to do the right +thing that they're always compatible + + align:start position:0% + + + + align:start position:0% + +now um + + align:start position:0% + + + + align:start position:0% + +the lesson that i take from that is that + + align:start position:0% +the lesson that i take from that is that + + + align:start position:0% +the lesson that i take from that is that +well i don't believe that they're always + + align:start position:0% +well i don't believe that they're always + + + align:start position:0% +well i don't believe that they're always +compatible + + align:start position:0% +compatible + + + align:start position:0% +compatible +but what i do believe is that competency + + align:start position:0% +but what i do believe is that competency + + + align:start position:0% +but what i do believe is that competency +is almost always compatible i mean if + + align:start position:0% +is almost always compatible i mean if + + + align:start position:0% +is almost always compatible i mean if +you're really good at what you do you + + align:start position:0% +you're really good at what you do you + + + align:start position:0% +you're really good at what you do you +should be able to do it and do the right + + align:start position:0% +should be able to do it and do the right + + + align:start position:0% +should be able to do it and do the right +thing + + align:start position:0% + + + + align:start position:0% + +now what i'm really after in that + + align:start position:0% +now what i'm really after in that + + + align:start position:0% +now what i'm really after in that +argument to be to be uh quite + + align:start position:0% +argument to be to be uh quite + + + align:start position:0% +argument to be to be uh quite +honest and specific about it is i am + + align:start position:0% +honest and specific about it is i am + + + align:start position:0% +honest and specific about it is i am +less concerned as to whether or not you + + align:start position:0% +less concerned as to whether or not you + + + align:start position:0% +less concerned as to whether or not you +can do both + + align:start position:0% +can do both + + + align:start position:0% +can do both +then i am concerned that to do one or + + align:start position:0% +then i am concerned that to do one or + + + align:start position:0% +then i am concerned that to do one or +the other is definitely incompetent i + + align:start position:0% +the other is definitely incompetent i + + + align:start position:0% +the other is definitely incompetent i +mean it builds into + + align:start position:0% +mean it builds into + + + align:start position:0% +mean it builds into +the culture + + align:start position:0% +the culture + + + align:start position:0% +the culture +that + + align:start position:0% +that + + + align:start position:0% +that +uh you're doing you're real smart + + align:start position:0% +uh you're doing you're real smart + + + align:start position:0% +uh you're doing you're real smart +if you can kill all of the enemy and + + align:start position:0% +if you can kill all of the enemy and + + + align:start position:0% +if you can kill all of the enemy and +their babies and their dogs and + + align:start position:0% +their babies and their dogs and + + + align:start position:0% +their babies and their dogs and +everything + + align:start position:0% +everything + + + align:start position:0% +everything +uh and say that well i had to do it + + align:start position:0% +uh and say that well i had to do it + + + align:start position:0% +uh and say that well i had to do it +confident you say well i'm just going to + + align:start position:0% +confident you say well i'm just going to + + + align:start position:0% +confident you say well i'm just going to +kill the soldiers the ones that are + + align:start position:0% +kill the soldiers the ones that are + + + align:start position:0% +kill the soldiers the ones that are +armed + + align:start position:0% +armed + + + align:start position:0% +armed +and uh not and we're not going to hit + + align:start position:0% +and uh not and we're not going to hit + + + align:start position:0% +and uh not and we're not going to hit +the civilians and i will be as effective + + align:start position:0% +the civilians and i will be as effective + + + align:start position:0% +the civilians and i will be as effective +as you are with that murder of everybody + + align:start position:0% +as you are with that murder of everybody + + + align:start position:0% +as you are with that murder of everybody +okay so it builds + + align:start position:0% +okay so it builds + + + align:start position:0% +okay so it builds +in a culture that going back to culture + + align:start position:0% +in a culture that going back to culture + + + align:start position:0% +in a culture that going back to culture +again it builds in what i call a bad + + align:start position:0% +again it builds in what i call a bad + + + align:start position:0% +again it builds in what i call a bad +culture + + align:start position:0% +culture + + + align:start position:0% +culture +now um + + align:start position:0% + + + + align:start position:0% + +uh so i think that that that we have the + + align:start position:0% +uh so i think that that that we have the + + + align:start position:0% +uh so i think that that that we have the +lay of the land ieee + + align:start position:0% +lay of the land ieee + + + align:start position:0% +lay of the land ieee +is really trying to say something that i + + align:start position:0% +is really trying to say something that i + + + align:start position:0% +is really trying to say something that i +don't think everybody can believe and + + align:start position:0% +don't think everybody can believe and + + + align:start position:0% +don't think everybody can believe and +that is that you can always + + align:start position:0% + + + + align:start position:0% + +do these things the right way i think + + align:start position:0% +do these things the right way i think + + + align:start position:0% +do these things the right way i think +that it's the right + + align:start position:0% +that it's the right + + + align:start position:0% +that it's the right +in other words here's what i would say + + align:start position:0% +in other words here's what i would say + + + align:start position:0% +in other words here's what i would say +now emphasize i'm taking a stand + + align:start position:0% +now emphasize i'm taking a stand + + + align:start position:0% +now emphasize i'm taking a stand +okay now you can take your stance but i + + align:start position:0% +okay now you can take your stance but i + + + align:start position:0% +okay now you can take your stance but i +can justify my stance + + align:start position:0% +can justify my stance + + + align:start position:0% +can justify my stance +um + + align:start position:0% +um + + + align:start position:0% +um +i would take that statement + + align:start position:0% +i would take that statement + + + align:start position:0% +i would take that statement +and put it in the + + align:start position:0% + + + + align:start position:0% + +preamble as an ideal that we shoot for + + align:start position:0% + + + + align:start position:0% + +the whole cannon + + align:start position:0% + + + + align:start position:0% + +the whole idea + + align:start position:0% +the whole idea + + + align:start position:0% +the whole idea +i would take the cannon out i would put + + align:start position:0% +i would take the cannon out i would put + + + align:start position:0% +i would take the cannon out i would put +it up there + + align:start position:0% +it up there + + + align:start position:0% +it up there +as the first draft and then i'd work on + + align:start position:0% +as the first draft and then i'd work on + + + align:start position:0% +as the first draft and then i'd work on +it until it all came out made sense + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +can we go back to nspe + + align:start position:0% +can we go back to nspe + + + align:start position:0% +can we go back to nspe +uh + + align:start position:0% +uh + + + align:start position:0% +uh +hi tony + + align:start position:0% +hi tony + + + align:start position:0% +hi tony +we're doing the uh nspe code + + align:start position:0% +we're doing the uh nspe code + + + align:start position:0% +we're doing the uh nspe code +uh + + align:start position:0% +uh + + + align:start position:0% +uh +what's the second canon + + align:start position:0% +what's the second canon + + + align:start position:0% +what's the second canon +are we done with the first + + align:start position:0% + + + + align:start position:0% + +um + + align:start position:0% +um + + + align:start position:0% +um +actually + + align:start position:0% +actually + + + align:start position:0% +actually +we've talked about what or read about + + align:start position:0% +we've talked about what or read about + + + align:start position:0% +we've talked about what or read about +what welfare means yeah + + align:start position:0% +what welfare means yeah + + + align:start position:0% +what welfare means yeah +but + + align:start position:0% +but + + + align:start position:0% +but +how + + align:start position:0% +how + + + align:start position:0% +how +do the people who subscribe to this code + + align:start position:0% +do the people who subscribe to this code + + + align:start position:0% +do the people who subscribe to this code +of ethics like how are they sure that + + align:start position:0% +of ethics like how are they sure that + + + align:start position:0% +of ethics like how are they sure that +they know what welfare means that was a + + align:start position:0% +they know what welfare means that was a + + + align:start position:0% +they know what welfare means that was a +hotly debated word + + align:start position:0% + + + + align:start position:0% + +right + + align:start position:0% +right + + + align:start position:0% +right +well that was a that was a + + align:start position:0% +well that was a that was a + + + align:start position:0% +well that was a that was a +i was in a meeting when um + + align:start position:0% + + + + align:start position:0% + +some engineers + + align:start position:0% + + + + align:start position:0% + +um three of them + + align:start position:0% +um three of them + + + align:start position:0% +um three of them +uh from the same state + + align:start position:0% +uh from the same state + + + align:start position:0% +uh from the same state +got up and walked out of the meeting + + align:start position:0% +got up and walked out of the meeting + + + align:start position:0% +got up and walked out of the meeting +said and we can't find a substitute for + + align:start position:0% +said and we can't find a substitute for + + + align:start position:0% +said and we can't find a substitute for +that word welfare we're not going to + + align:start position:0% +that word welfare we're not going to + + + align:start position:0% +that word welfare we're not going to +even participate those counters in it + + align:start position:0% +even participate those counters in it + + + align:start position:0% +even participate those counters in it +they got them walked out never came back + + align:start position:0% + + + + align:start position:0% + +because it had too many political + + align:start position:0% +because it had too many political + + + align:start position:0% +because it had too many political +connotations + + align:start position:0% +connotations + + + align:start position:0% +connotations +now the political connotation was + + align:start position:0% +now the political connotation was + + + align:start position:0% +now the political connotation was +that + + align:start position:0% +that + + + align:start position:0% +that +um + + align:start position:0% + + + + align:start position:0% + +the government is i mean this this was + + align:start position:0% +the government is i mean this this was + + + align:start position:0% +the government is i mean this this was +the connotation that was applied + + align:start position:0% +the connotation that was applied + + + align:start position:0% +the connotation that was applied +to the word welfare + + align:start position:0% +to the word welfare + + + align:start position:0% +to the word welfare +in + + align:start position:0% +in + + + align:start position:0% +in +these discussions + + align:start position:0% +these discussions + + + align:start position:0% +these discussions +the connotation was that the government + + align:start position:0% +the connotation was that the government + + + align:start position:0% +the connotation was that the government +is giving money to somebody not to work + + align:start position:0% +is giving money to somebody not to work + + + align:start position:0% +is giving money to somebody not to work +and they can live just as well as i am + + align:start position:0% +and they can live just as well as i am + + + align:start position:0% +and they can live just as well as i am +and i am working + + align:start position:0% +and i am working + + + align:start position:0% +and i am working +now that was + + align:start position:0% +now that was + + + align:start position:0% +now that was +the nightmare in the american psyche + + align:start position:0% +the nightmare in the american psyche + + + align:start position:0% +the nightmare in the american psyche +that + + align:start position:0% +that + + + align:start position:0% +that +was um + + align:start position:0% +was um + + + align:start position:0% +was um +that was built into the uh + + align:start position:0% +that was built into the uh + + + align:start position:0% +that was built into the uh +uh + + align:start position:0% +uh + + + align:start position:0% +uh +movements in the in the middle and late + + align:start position:0% +movements in the in the middle and late + + + align:start position:0% +movements in the in the middle and late +60s + + align:start position:0% +60s + + + align:start position:0% +60s +and the movement said that welfare was + + align:start position:0% +and the movement said that welfare was + + + align:start position:0% +and the movement said that welfare was +for + + align:start position:0% +for + + + align:start position:0% +for +uh people + + align:start position:0% +uh people + + + align:start position:0% +uh people +who either did not get their civil + + align:start position:0% +who either did not get their civil + + + align:start position:0% +who either did not get their civil +rights and therefore needed + + align:start position:0% +rights and therefore needed + + + align:start position:0% +rights and therefore needed +subsistence + + align:start position:0% +subsistence + + + align:start position:0% +subsistence +or + + align:start position:0% +or + + + align:start position:0% +or +that you really don't want to have a + + align:start position:0% +that you really don't want to have a + + + align:start position:0% +that you really don't want to have a +country + + align:start position:0% +country + + + align:start position:0% +country +where in people are suffering and have + + align:start position:0% +where in people are suffering and have + + + align:start position:0% +where in people are suffering and have +every reason to rise up against the + + align:start position:0% +every reason to rise up against the + + + align:start position:0% +every reason to rise up against the +country + + align:start position:0% + + + + align:start position:0% + +i mean no matter what your failure in + + align:start position:0% +i mean no matter what your failure in + + + align:start position:0% +i mean no matter what your failure in +life may be you don't want your child to + + align:start position:0% +life may be you don't want your child to + + + align:start position:0% +life may be you don't want your child to +starve + + align:start position:0% +starve + + + align:start position:0% +starve +and you will become a communist all of + + align:start position:0% +and you will become a communist all of + + + align:start position:0% +and you will become a communist all of +these other things okay + + align:start position:0% +these other things okay + + + align:start position:0% +these other things okay +so um + + align:start position:0% +so um + + + align:start position:0% +so um +branch dravidian + + align:start position:0% +branch dravidian + + + align:start position:0% +branch dravidian +all of these groups that break out + + align:start position:0% +all of these groups that break out + + + align:start position:0% +all of these groups that break out +uh are people who are sore + + align:start position:0% +uh are people who are sore + + + align:start position:0% +uh are people who are sore +about failure + + align:start position:0% +about failure + + + align:start position:0% +about failure +and you don't want a country + + align:start position:0% +and you don't want a country + + + align:start position:0% +and you don't want a country +particularly one that is that's what the + + align:start position:0% +particularly one that is that's what the + + + align:start position:0% +particularly one that is that's what the +argument went particularly when it's + + align:start position:0% +argument went particularly when it's + + + align:start position:0% +argument went particularly when it's +profitable i mean as rich as ours to + + align:start position:0% +profitable i mean as rich as ours to + + + align:start position:0% +profitable i mean as rich as ours to +have that problem + + align:start position:0% +have that problem + + + align:start position:0% +have that problem +okay so those were the two sides of it + + align:start position:0% +okay so those were the two sides of it + + + align:start position:0% +okay so those were the two sides of it +when they got it into + + align:start position:0% +when they got it into + + + align:start position:0% +when they got it into +these + + align:start position:0% +these + + + align:start position:0% +these +debates uh + + align:start position:0% +debates uh + + + align:start position:0% +debates uh +frankly i'll tell you uh + + align:start position:0% +frankly i'll tell you uh + + + align:start position:0% +frankly i'll tell you uh +i just don't know why uh the people who + + align:start position:0% +i just don't know why uh the people who + + + align:start position:0% +i just don't know why uh the people who +used the word welfare + + align:start position:0% +used the word welfare + + + align:start position:0% +used the word welfare +were not going to yield + + align:start position:0% +were not going to yield + + + align:start position:0% +were not going to yield +on that point + + align:start position:0% +on that point + + + align:start position:0% +on that point +i tried some other words + + align:start position:0% +i tried some other words + + + align:start position:0% +i tried some other words +i couldn't find it i didn't see where + + align:start position:0% +i couldn't find it i didn't see where + + + align:start position:0% +i couldn't find it i didn't see where +welfare + + align:start position:0% +welfare + + + align:start position:0% +welfare +was a necessary word + + align:start position:0% + + + + align:start position:0% + +and the people who + + align:start position:0% +and the people who + + + align:start position:0% +and the people who +were dissatisfied with it at the time of + + align:start position:0% +were dissatisfied with it at the time of + + + align:start position:0% +were dissatisfied with it at the time of +still dissatisfied they don't like that + + align:start position:0% +still dissatisfied they don't like that + + + align:start position:0% +still dissatisfied they don't like that +word + + align:start position:0% +word + + + align:start position:0% +word +the good news is the time has passed and + + align:start position:0% +the good news is the time has passed and + + + align:start position:0% +the good news is the time has passed and +a whole lot we've got a whole generation + + align:start position:0% +a whole lot we've got a whole generation + + + align:start position:0% +a whole lot we've got a whole generation +out here really doesn't know what that + + align:start position:0% +out here really doesn't know what that + + + align:start position:0% +out here really doesn't know what that +doesn't feel though + + align:start position:0% +doesn't feel though + + + align:start position:0% +doesn't feel though +right + + align:start position:0% +right + + + align:start position:0% +right +they'll happen to say well look in the + + align:start position:0% +they'll happen to say well look in the + + + align:start position:0% +they'll happen to say well look in the +dictionary + + align:start position:0% +dictionary + + + align:start position:0% +dictionary +get say okay + + align:start position:0% +get say okay + + + align:start position:0% +get say okay +so the good news is it no longer makes + + align:start position:0% +so the good news is it no longer makes + + + align:start position:0% +so the good news is it no longer makes +uh seems seems to me to make a + + align:start position:0% +uh seems seems to me to make a + + + align:start position:0% +uh seems seems to me to make a +difference + + align:start position:0% +difference + + + align:start position:0% +difference +but it was loaded and like i said + + align:start position:0% +but it was loaded and like i said + + + align:start position:0% +but it was loaded and like i said +i really i really wasn't uh + + align:start position:0% +i really i really wasn't uh + + + align:start position:0% +i really i really wasn't uh +i really i like the word welfare but i + + align:start position:0% +i really i like the word welfare but i + + + align:start position:0% +i really i like the word welfare but i +could find a substitute + + align:start position:0% +could find a substitute + + + align:start position:0% +could find a substitute +all right if that makes you mad + + align:start position:0% +all right if that makes you mad + + + align:start position:0% +all right if that makes you mad +i'll find another one that means the + + align:start position:0% +i'll find another one that means the + + + align:start position:0% +i'll find another one that means the +same thing + + align:start position:0% +same thing + + + align:start position:0% +same thing +and if that makes you mad then i see + + align:start position:0% +and if that makes you mad then i see + + + align:start position:0% +and if that makes you mad then i see +there's no way for us to + + align:start position:0% +there's no way for us to + + + align:start position:0% +there's no way for us to +come to any conclusion but + + align:start position:0% +come to any conclusion but + + + align:start position:0% +come to any conclusion but +i was willing to find a substitute but + + align:start position:0% +i was willing to find a substitute but + + + align:start position:0% +i was willing to find a substitute but +the people who + + align:start position:0% +the people who + + + align:start position:0% +the people who +laid on that word welfare bang there + + align:start position:0% + + + + align:start position:0% + +that's right and they were going to do + + align:start position:0% +that's right and they were going to do + + + align:start position:0% +that's right and they were going to do +it and it won if you want to put it in + + align:start position:0% +it and it won if you want to put it in + + + align:start position:0% +it and it won if you want to put it in +terms of winning and losing + + align:start position:0% +terms of winning and losing + + + align:start position:0% +terms of winning and losing +uh so yeah welfare was a that's a good + + align:start position:0% +uh so yeah welfare was a that's a good + + + align:start position:0% +uh so yeah welfare was a that's a good +term it + + align:start position:0% +term it + + + align:start position:0% +term it +was a loaded term in those days loaded + + align:start position:0% + + + + align:start position:0% + +but it came out + + align:start position:0% +but it came out + + + align:start position:0% +but it came out +okay where else are we now + + align:start position:0% + + + + align:start position:0% + +somebody read number two + + align:start position:0% +somebody read number two + + + align:start position:0% +somebody read number two +you have a longer version i have + + align:start position:0% +you have a longer version i have + + + align:start position:0% +you have a longer version i have +performed services only in areas + + align:start position:0% + + + + align:start position:0% + +now that was a + + align:start position:0% +now that was a + + + align:start position:0% +now that was a +contested one + + align:start position:0% + + + + align:start position:0% + +i thought a lot about that one + + align:start position:0% +i thought a lot about that one + + + align:start position:0% +i thought a lot about that one +yes + + align:start position:0% +yes + + + align:start position:0% +yes +well + + align:start position:0% +well + + + align:start position:0% +well +yes + + align:start position:0% +yes + + + align:start position:0% +yes +highly contested + + align:start position:0% + + + + align:start position:0% + +that's right + + align:start position:0% +that's right + + + align:start position:0% +that's right +i'll tell you why + + align:start position:0% +i'll tell you why + + + align:start position:0% +i'll tell you why +uh the people + + align:start position:0% +uh the people + + + align:start position:0% +uh the people +there was one guy i can't remember his + + align:start position:0% +there was one guy i can't remember his + + + align:start position:0% +there was one guy i can't remember his +name or worry what organization he + + align:start position:0% +name or worry what organization he + + + align:start position:0% +name or worry what organization he +represented because in the aaes + + align:start position:0% +represented because in the aaes + + + align:start position:0% +represented because in the aaes +everybody was a representative of one of + + align:start position:0% +everybody was a representative of one of + + + align:start position:0% +everybody was a representative of one of +the member organizations + + align:start position:0% +the member organizations + + + align:start position:0% +the member organizations +uh i can't remember what organization + + align:start position:0% +uh i can't remember what organization + + + align:start position:0% +uh i can't remember what organization +but he put it very articulately and he + + align:start position:0% +but he put it very articulately and he + + + align:start position:0% +but he put it very articulately and he +fought very hard for it + + align:start position:0% +fought very hard for it + + + align:start position:0% +fought very hard for it +lost in the end but he brought fair his + + align:start position:0% +lost in the end but he brought fair his + + + align:start position:0% +lost in the end but he brought fair his +uh his argument was + + align:start position:0% +uh his argument was + + + align:start position:0% +uh his argument was +that the two kinds + + align:start position:0% +that the two kinds + + + align:start position:0% +that the two kinds +of engineering organizations big ones + + align:start position:0% +of engineering organizations big ones + + + align:start position:0% +of engineering organizations big ones +and little ones + + align:start position:0% + + + + align:start position:0% + +so if you got a small company out here + + align:start position:0% +so if you got a small company out here + + + align:start position:0% +so if you got a small company out here +let's say the three of you all get + + align:start position:0% +let's say the three of you all get + + + align:start position:0% +let's say the three of you all get +together and say you're gonna + + align:start position:0% +together and say you're gonna + + + align:start position:0% +together and say you're gonna +get incorporated + + align:start position:0% +get incorporated + + + align:start position:0% +get incorporated +and you wind up hiring 20 people + + align:start position:0% +and you wind up hiring 20 people + + + align:start position:0% +and you wind up hiring 20 people +and you're making good money all right + + align:start position:0% +and you're making good money all right + + + align:start position:0% +and you're making good money all right +then + + align:start position:0% +then + + + align:start position:0% +then +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +something on the job + + align:start position:0% +something on the job + + + align:start position:0% +something on the job +a fuse bus + + align:start position:0% +a fuse bus + + + align:start position:0% +a fuse bus +loose and you have to fix that + + align:start position:0% +loose and you have to fix that + + + align:start position:0% +loose and you have to fix that +electrical wiring you don't have the + + align:start position:0% +electrical wiring you don't have the + + + align:start position:0% +electrical wiring you don't have the +money to be going out to hire an + + align:start position:0% +money to be going out to hire an + + + align:start position:0% +money to be going out to hire an +electrical engineer + + align:start position:0% +electrical engineer + + + align:start position:0% +electrical engineer +to come in on the spot because you got + + align:start position:0% +to come in on the spot because you got + + + align:start position:0% +to come in on the spot because you got +your critical pass schedule you got to + + align:start position:0% +your critical pass schedule you got to + + + align:start position:0% +your critical pass schedule you got to +finish this job today somebody's got to + + align:start position:0% +finish this job today somebody's got to + + + align:start position:0% +finish this job today somebody's got to +go to crawl down and then fix that wire + + align:start position:0% +go to crawl down and then fix that wire + + + align:start position:0% +go to crawl down and then fix that wire +so um the the idea was that uh + + align:start position:0% +so um the the idea was that uh + + + align:start position:0% +so um the the idea was that uh +requiring engineers to perform only in + + align:start position:0% +requiring engineers to perform only in + + + align:start position:0% +requiring engineers to perform only in +the areas of their competence was going + + align:start position:0% +the areas of their competence was going + + + align:start position:0% +the areas of their competence was going +to put the small business engineers out + + align:start position:0% +to put the small business engineers out + + + align:start position:0% +to put the small business engineers out +of + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +can small business sort of find a way + + align:start position:0% +can small business sort of find a way + + + align:start position:0% +can small business sort of find a way +around this campaign + + align:start position:0% +around this campaign + + + align:start position:0% +around this campaign +what happened i think in the end was the + + align:start position:0% +what happened i think in the end was the + + + align:start position:0% +what happened i think in the end was the +small business just kept doing what they + + align:start position:0% +small business just kept doing what they + + + align:start position:0% +small business just kept doing what they +were doing and + + align:start position:0% +were doing and + + + align:start position:0% +were doing and +and they uh + + align:start position:0% +and they uh + + + align:start position:0% +and they uh +no big cases come up + + align:start position:0% +no big cases come up + + + align:start position:0% +no big cases come up +and the basic attitude that we talked + + align:start position:0% +and the basic attitude that we talked + + + align:start position:0% +and the basic attitude that we talked +about when i was chair of the committee + + align:start position:0% +about when i was chair of the committee + + + align:start position:0% +about when i was chair of the committee +was + + align:start position:0% +was + + + align:start position:0% +was +that look um + + align:start position:0% +that look um + + + align:start position:0% +that look um +you know + + align:start position:0% +you know + + + align:start position:0% +you know +judges and juries + + align:start position:0% +judges and juries + + + align:start position:0% +judges and juries +are reasonable to some level at some + + align:start position:0% +are reasonable to some level at some + + + align:start position:0% +are reasonable to some level at some +level they + + align:start position:0% +level they + + + align:start position:0% +level they +they're going to know that + + align:start position:0% +they're going to know that + + + align:start position:0% +they're going to know that +you know you're not a concrete foreman + + align:start position:0% +you know you're not a concrete foreman + + + align:start position:0% +you know you're not a concrete foreman +but + + align:start position:0% +but + + + align:start position:0% +but +some you wanted to pour just enough + + align:start position:0% +some you wanted to pour just enough + + + align:start position:0% +some you wanted to pour just enough +concrete in here + + align:start position:0% +concrete in here + + + align:start position:0% +concrete in here +to put + + align:start position:0% +to put + + + align:start position:0% +to put +an electrical apparatus that your + + align:start position:0% +an electrical apparatus that your + + + align:start position:0% +an electrical apparatus that your +company makes on top of + + align:start position:0% +company makes on top of + + + align:start position:0% +company makes on top of +and nobody came in here on time you got + + align:start position:0% +and nobody came in here on time you got + + + align:start position:0% +and nobody came in here on time you got +to do it so somebody said well let's go + + align:start position:0% +to do it so somebody said well let's go + + + align:start position:0% +to do it so somebody said well let's go +mix the concrete i did it for my son's + + align:start position:0% +mix the concrete i did it for my son's + + + align:start position:0% +mix the concrete i did it for my son's +dog house you know + + align:start position:0% +dog house you know + + + align:start position:0% +dog house you know +and you throw it in there somebody the + + align:start position:0% +and you throw it in there somebody the + + + align:start position:0% +and you throw it in there somebody the +jury some jury is going to be + + align:start position:0% +jury some jury is going to be + + + align:start position:0% +jury some jury is going to be +sympathetic to that + + align:start position:0% +sympathetic to that + + + align:start position:0% +sympathetic to that +and just don't let it get out of hand + + align:start position:0% +and just don't let it get out of hand + + + align:start position:0% +and just don't let it get out of hand +don't don't have a nuclear device + + align:start position:0% +don't don't have a nuclear device + + + align:start position:0% +don't don't have a nuclear device +in the product you make that goes bad + + align:start position:0% +in the product you make that goes bad + + + align:start position:0% +in the product you make that goes bad +and you try to fix it + + align:start position:0% +and you try to fix it + + + align:start position:0% +and you try to fix it +don't go crazy so i think that uh what + + align:start position:0% +don't go crazy so i think that uh what + + + align:start position:0% +don't go crazy so i think that uh what +happened with that case was that cooler + + align:start position:0% +happened with that case was that cooler + + + align:start position:0% +happened with that case was that cooler +heads prevailed in the end + + align:start position:0% + + + + align:start position:0% + +yeah i think that resolved + + align:start position:0% +yeah i think that resolved + + + align:start position:0% +yeah i think that resolved +some issues because at first + + align:start position:0% + + + + align:start position:0% + +ethical but that's not really what it's + + align:start position:0% +ethical but that's not really what it's + + + align:start position:0% +ethical but that's not really what it's +saying it's saying + + align:start position:0% +saying it's saying + + + align:start position:0% +saying it's saying +it's unethical + + align:start position:0% +it's unethical + + + align:start position:0% +it's unethical +to do something that you're not + + align:start position:0% +to do something that you're not + + + align:start position:0% +to do something that you're not +confident like it's not unethical or not + + align:start position:0% +confident like it's not unethical or not + + + align:start position:0% +confident like it's not unethical or not +you know how to do something until you + + align:start position:0% +you know how to do something until you + + + align:start position:0% +you know how to do something until you +ignore something so maybe that's the + + align:start position:0% +ignore something so maybe that's the + + + align:start position:0% +ignore something so maybe that's the +idea that i play with + + align:start position:0% + + + + align:start position:0% + +you thought more was this at first + + align:start position:0% +you thought more was this at first + + + align:start position:0% +you thought more was this at first +glance i think we've had a conversation + + align:start position:0% +glance i think we've had a conversation + + + align:start position:0% +glance i think we've had a conversation +before about i think it was going to + + align:start position:0% +before about i think it was going to + + + align:start position:0% +before about i think it was going to +know what we were talking about + + align:start position:0% +know what we were talking about + + + align:start position:0% +know what we were talking about +yeah competency came up in chernobyl + + align:start position:0% +yeah competency came up in chernobyl + + + align:start position:0% +yeah competency came up in chernobyl +so yeah + + align:start position:0% + + + + align:start position:0% + +that that's what's unethical attention + + align:start position:0% +that that's what's unethical attention + + + align:start position:0% +that that's what's unethical attention +to not necessarily that + + align:start position:0% +to not necessarily that + + + align:start position:0% +to not necessarily that +you know + + align:start position:0% +you know + + + align:start position:0% +you know +maybe you're not great at it and you try + + align:start position:0% +maybe you're not great at it and you try + + + align:start position:0% +maybe you're not great at it and you try +and fail nothing ethically is wrong it's + + align:start position:0% +and fail nothing ethically is wrong it's + + + align:start position:0% +and fail nothing ethically is wrong it's +just you've actually tried an attempt to + + align:start position:0% +just you've actually tried an attempt to + + + align:start position:0% +just you've actually tried an attempt to +do something + + align:start position:0% + + + + align:start position:0% + +well that's that was one of the big + + align:start position:0% +well that's that was one of the big + + + align:start position:0% +well that's that was one of the big +issues that i brought to the table as a + + align:start position:0% +issues that i brought to the table as a + + + align:start position:0% +issues that i brought to the table as a +person who had studied ethics formally + + align:start position:0% +person who had studied ethics formally + + + align:start position:0% +person who had studied ethics formally +uh that + + align:start position:0% +uh that + + + align:start position:0% +uh that +and + + align:start position:0% +and + + + align:start position:0% +and +but engineers had very strong sentiments + + align:start position:0% +but engineers had very strong sentiments + + + align:start position:0% +but engineers had very strong sentiments +that if you didn't know + + align:start position:0% +that if you didn't know + + + align:start position:0% +that if you didn't know +how to solve a certain kind of problem + + align:start position:0% +how to solve a certain kind of problem + + + align:start position:0% +how to solve a certain kind of problem +you were unethical + + align:start position:0% +you were unethical + + + align:start position:0% +you were unethical +they + + align:start position:0% +they + + + align:start position:0% +they +and i tried to tell them no + + align:start position:0% +and i tried to tell them no + + + align:start position:0% +and i tried to tell them no +you got to separate that out + + align:start position:0% +you got to separate that out + + + align:start position:0% +you got to separate that out +and in the end cooler heads prevailed on + + align:start position:0% +and in the end cooler heads prevailed on + + + align:start position:0% +and in the end cooler heads prevailed on +that one too + + align:start position:0% +that one too + + + align:start position:0% +that one too +but uh there was a basic sentiment among + + align:start position:0% +but uh there was a basic sentiment among + + + align:start position:0% +but uh there was a basic sentiment among +engineers that + + align:start position:0% + + + + align:start position:0% + +that if there were certain things you + + align:start position:0% +that if there were certain things you + + + align:start position:0% +that if there were certain things you +didn't know + + align:start position:0% +didn't know + + + align:start position:0% +didn't know +and you shouldn't be practicing + + align:start position:0% +and you shouldn't be practicing + + + align:start position:0% +and you shouldn't be practicing +and it was unethical + + align:start position:0% + + + + align:start position:0% + +and + + align:start position:0% +and + + + align:start position:0% +and +i'll tell you what made their arguments + + align:start position:0% +i'll tell you what made their arguments + + + align:start position:0% +i'll tell you what made their arguments +um + + align:start position:0% + + + + align:start position:0% + +strong if not entirely compelling + + align:start position:0% + + + + align:start position:0% + +they would make a metaphor with + + align:start position:0% +they would make a metaphor with + + + align:start position:0% +they would make a metaphor with +physicians + + align:start position:0% +physicians + + + align:start position:0% +physicians +okay so you're sitting up there your + + align:start position:0% +okay so you're sitting up there your + + + align:start position:0% +okay so you're sitting up there your +heart is going bad you're about to die + + align:start position:0% +heart is going bad you're about to die + + + align:start position:0% +heart is going bad you're about to die +the physician comes in saying well i + + align:start position:0% +the physician comes in saying well i + + + align:start position:0% +the physician comes in saying well i +never studied the heart but i i will cut + + align:start position:0% +never studied the heart but i i will cut + + + align:start position:0% +never studied the heart but i i will cut +your heart out today anyway i mean you + + align:start position:0% +your heart out today anyway i mean you + + + align:start position:0% +your heart out today anyway i mean you +know part of it i now there's there's + + align:start position:0% +know part of it i now there's there's + + + align:start position:0% +know part of it i now there's there's +something unethical and competency tied + + align:start position:0% +something unethical and competency tied + + + align:start position:0% +something unethical and competency tied +into that + + align:start position:0% +into that + + + align:start position:0% +into that +and then they make the metaphor back to + + align:start position:0% +and then they make the metaphor back to + + + align:start position:0% +and then they make the metaphor back to +engineering and engineers start thinking + + align:start position:0% +engineering and engineers start thinking + + + align:start position:0% +engineering and engineers start thinking +and we have to hold it maybe cooler + + align:start position:0% +and we have to hold it maybe cooler + + + align:start position:0% +and we have to hold it maybe cooler +heads have prevailed in these situations + + align:start position:0% +heads have prevailed in these situations + + + align:start position:0% +heads have prevailed in these situations +okay but that was hot that was a hot + + align:start position:0% +okay but that was hot that was a hot + + + align:start position:0% +okay but that was hot that was a hot +issue + + align:start position:0% + + + + align:start position:0% + +yeah + + align:start position:0% +yeah + + + align:start position:0% +yeah +and we're not pouring concrete for a + + align:start position:0% +and we're not pouring concrete for a + + + align:start position:0% +and we're not pouring concrete for a +column that's going to sustain + + align:start position:0% +column that's going to sustain + + + align:start position:0% +column that's going to sustain +30 stories + + align:start position:0% +30 stories + + + align:start position:0% +30 stories +of stuff on top we just have a little + + align:start position:0% +of stuff on top we just have a little + + + align:start position:0% +of stuff on top we just have a little +thing over + + align:start position:0% +thing over + + + align:start position:0% +thing over +if it cracks + + align:start position:0% +if it cracks + + + align:start position:0% +if it cracks +then we'll pay for it + + align:start position:0% + + + + align:start position:0% + +you try to work that's + + align:start position:0% +you try to work that's + + + align:start position:0% +you try to work that's +you know cooler has prevail in the + + align:start position:0% +you know cooler has prevail in the + + + align:start position:0% +you know cooler has prevail in the +courtroom sometimes take your + + align:start position:0% +courtroom sometimes take your + + + align:start position:0% +courtroom sometimes take your +chances but um i think that underneath + + align:start position:0% +chances but um i think that underneath + + + align:start position:0% +chances but um i think that underneath +the surface + + align:start position:0% +the surface + + + align:start position:0% +the surface +remember i told you there are certain + + align:start position:0% +remember i told you there are certain + + + align:start position:0% +remember i told you there are certain +things operating + + align:start position:0% +things operating + + + align:start position:0% +things operating +uh underneath the surface of discussion + + align:start position:0% + + + + align:start position:0% + +that nobody would deny and sometimes + + align:start position:0% +that nobody would deny and sometimes + + + align:start position:0% +that nobody would deny and sometimes +some of it has been written one is that + + align:start position:0% +some of it has been written one is that + + + align:start position:0% +some of it has been written one is that +engineers always felt + + align:start position:0% +engineers always felt + + + align:start position:0% +engineers always felt +and probably still feel + + align:start position:0% +and probably still feel + + + align:start position:0% +and probably still feel +that they are not uh accepted as + + align:start position:0% +that they are not uh accepted as + + + align:start position:0% +that they are not uh accepted as +professionals like doctors and lawyers + + align:start position:0% +professionals like doctors and lawyers + + + align:start position:0% +professionals like doctors and lawyers +are + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +and they're proud of their profession + + align:start position:0% +and they're proud of their profession + + + align:start position:0% +and they're proud of their profession +and + + align:start position:0% +and + + + align:start position:0% +and +mainly + + align:start position:0% +mainly + + + align:start position:0% +mainly +because + + align:start position:0% +because + + + align:start position:0% +because +not because of the good things that are + + align:start position:0% +not because of the good things that are + + + align:start position:0% +not because of the good things that are +here in this preamble + + align:start position:0% +here in this preamble + + + align:start position:0% +here in this preamble +but because actually what you had said + + align:start position:0% +but because actually what you had said + + + align:start position:0% +but because actually what you had said +ms best yeah a couple classes ago and + + align:start position:0% +ms best yeah a couple classes ago and + + + align:start position:0% +ms best yeah a couple classes ago and +that was they know what it was like to + + align:start position:0% +that was they know what it was like to + + + align:start position:0% +that was they know what it was like to +be in school + + align:start position:0% +be in school + + + align:start position:0% +be in school +and take hard courses when everybody + + align:start position:0% +and take hard courses when everybody + + + align:start position:0% +and take hard courses when everybody +else + + align:start position:0% +else + + + align:start position:0% +else +could not pass these courses and we not + + align:start position:0% +could not pass these courses and we not + + + align:start position:0% +could not pass these courses and we not +only had to pass them but do well in + + align:start position:0% +only had to pass them but do well in + + + align:start position:0% +only had to pass them but do well in +them in order to get a degree + + align:start position:0% +them in order to get a degree + + + align:start position:0% +them in order to get a degree +and there's a lot and there's a and + + align:start position:0% +and there's a lot and there's a and + + + align:start position:0% +and there's a lot and there's a and +there is under the surface + + align:start position:0% +there is under the surface + + + align:start position:0% +there is under the surface +in engineering + + align:start position:0% +in engineering + + + align:start position:0% +in engineering +there is a little bit of bitterness + + align:start position:0% +there is a little bit of bitterness + + + align:start position:0% +there is a little bit of bitterness +about + + align:start position:0% +about + + + align:start position:0% +about +all of that + + align:start position:0% +all of that + + + align:start position:0% +all of that +um + + align:start position:0% +um + + + align:start position:0% +um +i know of one case + + align:start position:0% +i know of one case + + + align:start position:0% +i know of one case +where there was this professor + + align:start position:0% + + + + align:start position:0% + +uh who had something like two or three + + align:start position:0% +uh who had something like two or three + + + align:start position:0% +uh who had something like two or three +hundred publications + + align:start position:0% +hundred publications + + + align:start position:0% +hundred publications +was editor of three journals actually + + align:start position:0% +was editor of three journals actually + + + align:start position:0% +was editor of three journals actually +the guy who told me said it was in her + + align:start position:0% +the guy who told me said it was in her + + + align:start position:0% +the guy who told me said it was in her +four journals + + align:start position:0% +four journals + + + align:start position:0% +four journals +and + + align:start position:0% +and + + + align:start position:0% +and +was a consultant + + align:start position:0% + + + + align:start position:0% + +you want the answer + + align:start position:0% +you want the answer + + + align:start position:0% +you want the answer +it is a term it has two words it's + + align:start position:0% +it is a term it has two words it's + + + align:start position:0% +it is a term it has two words it's +called graduate students + + align:start position:0% +called graduate students + + + align:start position:0% +called graduate students +[Laughter] + + align:start position:0% + + + + align:start position:0% + +oh + + align:start position:0% +oh + + + align:start position:0% +oh +and uh he's at the top of his profession + + align:start position:0% +and uh he's at the top of his profession + + + align:start position:0% +and uh he's at the top of his profession +he had this one student + + align:start position:0% +he had this one student + + + align:start position:0% +he had this one student +that got a master's degree under him + + align:start position:0% +that got a master's degree under him + + + align:start position:0% +that got a master's degree under him +just barely got through + + align:start position:0% +just barely got through + + + align:start position:0% +just barely got through +and + + align:start position:0% +and + + + align:start position:0% +and +five or six ten years later that + + align:start position:0% +five or six ten years later that + + + align:start position:0% +five or six ten years later that +particular + + align:start position:0% +particular + + + align:start position:0% +particular +former student gave a party to his house + + align:start position:0% +former student gave a party to his house + + + align:start position:0% +former student gave a party to his house +he had gone out and had made a little + + align:start position:0% +he had gone out and had made a little + + + align:start position:0% +he had gone out and had made a little +gotten a little business and + + align:start position:0% +gotten a little business and + + + align:start position:0% +gotten a little business and +became successful + + align:start position:0% +became successful + + + align:start position:0% +became successful +and when the professor went to the party + + align:start position:0% +and when the professor went to the party + + + align:start position:0% +and when the professor went to the party +the house was three times as big as the + + align:start position:0% +the house was three times as big as the + + + align:start position:0% +the house was three times as big as the +professor's house + + align:start position:0% +professor's house + + + align:start position:0% +professor's house +had a rolls royce + + align:start position:0% +had a rolls royce + + + align:start position:0% +had a rolls royce +and you know one of the four parking + + align:start position:0% +and you know one of the four parking + + + align:start position:0% +and you know one of the four parking +garages had four full chimneys you know + + align:start position:0% +garages had four full chimneys you know + + + align:start position:0% +garages had four full chimneys you know +the whole bit + + align:start position:0% +the whole bit + + + align:start position:0% +the whole bit +and + + align:start position:0% +and + + + align:start position:0% +and +the story goes on about how this man + + align:start position:0% +the story goes on about how this man + + + align:start position:0% +the story goes on about how this man +began to drink and wound up in + + align:start position:0% +began to drink and wound up in + + + align:start position:0% +began to drink and wound up in +a in a home + + align:start position:0% +a in a home + + + align:start position:0% +a in a home +the professor + + align:start position:0% +the professor + + + align:start position:0% +the professor +i just tore him up so you get one story + + align:start position:0% +i just tore him up so you get one story + + + align:start position:0% +i just tore him up so you get one story +out there there was another story that + + align:start position:0% +out there there was another story that + + + align:start position:0% +out there there was another story that +hit the newspapers i know about this + + align:start position:0% +hit the newspapers i know about this + + + align:start position:0% +hit the newspapers i know about this +story personally + + align:start position:0% +story personally + + + align:start position:0% +story personally +uh because this particular professor + + align:start position:0% +uh because this particular professor + + + align:start position:0% +uh because this particular professor +taught me a class in graduate school + + align:start position:0% +taught me a class in graduate school + + + align:start position:0% +taught me a class in graduate school +it turns out that this particular i + + align:start position:0% +it turns out that this particular i + + + align:start position:0% +it turns out that this particular i +won't call a name because in order to + + align:start position:0% +won't call a name because in order to + + + align:start position:0% +won't call a name because in order to +call the name i have to get all my facts + + align:start position:0% +call the name i have to get all my facts + + + align:start position:0% +call the name i have to get all my facts +right + + align:start position:0% +right + + + align:start position:0% +right +but the facts are not only + + align:start position:0% +but the facts are not only + + + align:start position:0% +but the facts are not only +on the record in the courts but they're + + align:start position:0% +on the record in the courts but they're + + + align:start position:0% +on the record in the courts but they're +in the newspapers this was nnaaup + + align:start position:0% +in the newspapers this was nnaaup + + + align:start position:0% +in the newspapers this was nnaaup +all kinds of stuff but this professor + + align:start position:0% +all kinds of stuff but this professor + + + align:start position:0% +all kinds of stuff but this professor +turns out he was um + + align:start position:0% +turns out he was um + + + align:start position:0% +turns out he was um +a very good teacher + + align:start position:0% +a very good teacher + + + align:start position:0% +a very good teacher +and had published some textbooks i'm + + align:start position:0% +and had published some textbooks i'm + + + align:start position:0% +and had published some textbooks i'm +talking about springer verlag + + align:start position:0% +talking about springer verlag + + + align:start position:0% +talking about springer verlag +top of the line textbooks required + + align:start position:0% +top of the line textbooks required + + + align:start position:0% +top of the line textbooks required +reading at mit stanford berkeley + + align:start position:0% +reading at mit stanford berkeley + + + align:start position:0% +reading at mit stanford berkeley +princeton okay + + align:start position:0% + + + + align:start position:0% + +and but he did not have any research + + align:start position:0% + + + + align:start position:0% + +none whatsoever he was just a teacher + + align:start position:0% +none whatsoever he was just a teacher + + + align:start position:0% +none whatsoever he was just a teacher +then it came out + + align:start position:0% +then it came out + + + align:start position:0% +then it came out +that he was a full professor + + align:start position:0% +that he was a full professor + + + align:start position:0% +that he was a full professor +with tenure + + align:start position:0% +with tenure + + + align:start position:0% +with tenure +with a full-time appointment at three + + align:start position:0% +with a full-time appointment at three + + + align:start position:0% +with a full-time appointment at three +different universities + + align:start position:0% +different universities + + + align:start position:0% +different universities +simultaneously + + align:start position:0% +simultaneously + + + align:start position:0% +simultaneously +and he had his schedule made out so that + + align:start position:0% +and he had his schedule made out so that + + + align:start position:0% +and he had his schedule made out so that +at one place he had courses only monday + + align:start position:0% +at one place he had courses only monday + + + align:start position:0% +at one place he had courses only monday +wednesday and friday in the morning + + align:start position:0% +wednesday and friday in the morning + + + align:start position:0% +wednesday and friday in the morning +and other places monday wednesday and + + align:start position:0% +and other places monday wednesday and + + + align:start position:0% +and other places monday wednesday and +friday in the afternoon + + align:start position:0% +friday in the afternoon + + + align:start position:0% +friday in the afternoon +and then the one that was out of town in + + align:start position:0% +and then the one that was out of town in + + + align:start position:0% +and then the one that was out of town in +pennsylvania he was in washington + + align:start position:0% +pennsylvania he was in washington + + + align:start position:0% +pennsylvania he was in washington +was in uh tuesday thursday + + align:start position:0% + + + + align:start position:0% + +and they called him and uh they roasted + + align:start position:0% +and they called him and uh they roasted + + + align:start position:0% +and they called him and uh they roasted +him on a spit but + + align:start position:0% +him on a spit but + + + align:start position:0% +him on a spit but +there was a lot of sympathy for his case + + align:start position:0% +there was a lot of sympathy for his case + + + align:start position:0% +there was a lot of sympathy for his case +a lot of other factors came in + + align:start position:0% +a lot of other factors came in + + + align:start position:0% +a lot of other factors came in +he had a daughter that was sick and his + + align:start position:0% +he had a daughter that was sick and his + + + align:start position:0% +he had a daughter that was sick and his +wife was dead you know about all of + + align:start position:0% +wife was dead you know about all of + + + align:start position:0% +wife was dead you know about all of +these things but there was one other + + align:start position:0% +these things but there was one other + + + align:start position:0% +these things but there was one other +factor that came in there that really + + align:start position:0% +factor that came in there that really + + + align:start position:0% +factor that came in there that really +worked on the academic profession very + + align:start position:0% +worked on the academic profession very + + + align:start position:0% +worked on the academic profession very +hard and that was + + align:start position:0% +hard and that was + + + align:start position:0% +hard and that was +is this what a good teacher has to do + + align:start position:0% + + + + align:start position:0% + +in order just to make pay bills and + + align:start position:0% +in order just to make pay bills and + + + align:start position:0% +in order just to make pay bills and +stuff + + align:start position:0% +stuff + + + align:start position:0% +stuff +you know maybe we're doing too much to + + align:start position:0% +you know maybe we're doing too much to + + + align:start position:0% +you know maybe we're doing too much to +emphasize the research part of it + + align:start position:0% +emphasize the research part of it + + + align:start position:0% +emphasize the research part of it +and so uh his his case has never been + + align:start position:0% +and so uh his his case has never been + + + align:start position:0% +and so uh his his case has never been +forgotten + + align:start position:0% + + + + align:start position:0% + +so uh under excuse me underneath the + + align:start position:0% +so uh under excuse me underneath the + + + align:start position:0% +so uh under excuse me underneath the +surface you have all of these currents + + align:start position:0% + + + + align:start position:0% + +the issue was that it was uh that it was + + align:start position:0% +the issue was that it was uh that it was + + + align:start position:0% +the issue was that it was uh that it was +illegal + + align:start position:0% +illegal + + + align:start position:0% +illegal +that you cannot the issue was that the + + align:start position:0% +that you cannot the issue was that the + + + align:start position:0% +that you cannot the issue was that the +pro + + align:start position:0% +pro + + + align:start position:0% +pro +they want + + align:start position:0% +they want + + + align:start position:0% +they want +the president want to fire him + + align:start position:0% + + + + align:start position:0% + +and + + align:start position:0% +and + + + align:start position:0% +and +uh what and + + align:start position:0% +uh what and + + + align:start position:0% +uh what and +there was a lot of debate on one side or + + align:start position:0% +there was a lot of debate on one side or + + + align:start position:0% +there was a lot of debate on one side or +the other as to whether or not + + align:start position:0% +the other as to whether or not + + + align:start position:0% +the other as to whether or not +a faculty member can have more than one + + align:start position:0% +a faculty member can have more than one + + + align:start position:0% +a faculty member can have more than one +job and + + align:start position:0% +job and + + + align:start position:0% +job and +they they pointed to this + + align:start position:0% +they they pointed to this + + + align:start position:0% +they they pointed to this +tradition of the one day a week + + align:start position:0% +tradition of the one day a week + + + align:start position:0% +tradition of the one day a week +consulting + + align:start position:0% +consulting + + + align:start position:0% +consulting +that when you that there's this + + align:start position:0% +that when you that there's this + + + align:start position:0% +that when you that there's this +understanding + + align:start position:0% +understanding + + + align:start position:0% +understanding +that when you take on a faculty position + + align:start position:0% +that when you take on a faculty position + + + align:start position:0% +that when you take on a faculty position +you've got one day a week + + align:start position:0% +you've got one day a week + + + align:start position:0% +you've got one day a week +to do what you want + + align:start position:0% + + + + align:start position:0% + +and that usually means + + align:start position:0% +and that usually means + + + align:start position:0% +and that usually means +consulting or doing something that + + align:start position:0% +consulting or doing something that + + + align:start position:0% +consulting or doing something that +will enhance your abilities to do + + align:start position:0% +will enhance your abilities to do + + + align:start position:0% +will enhance your abilities to do +teaching and research + + align:start position:0% +teaching and research + + + align:start position:0% +teaching and research +you're not going to the beach + + align:start position:0% + + + + align:start position:0% + +but but it's up to you to decide is that + + align:start position:0% +but but it's up to you to decide is that + + + align:start position:0% +but but it's up to you to decide is that +it's just an understanding that has been + + align:start position:0% +it's just an understanding that has been + + + align:start position:0% +it's just an understanding that has been +the case for many many years and it has + + align:start position:0% +the case for many many years and it has + + + align:start position:0% +the case for many many years and it has +influence in the courts + + align:start position:0% +influence in the courts + + + align:start position:0% +influence in the courts +courts say this is they'll get all of + + align:start position:0% +courts say this is they'll get all of + + + align:start position:0% +courts say this is they'll get all of +these + + align:start position:0% +these + + + align:start position:0% +these +college presidents and people get up and + + align:start position:0% +college presidents and people get up and + + + align:start position:0% +college presidents and people get up and +say yeah that's it's just understood + + align:start position:0% +say yeah that's it's just understood + + + align:start position:0% +say yeah that's it's just understood +right + + align:start position:0% +right + + + align:start position:0% +right +so um + + align:start position:0% + + + + align:start position:0% + +you get you suppose you're supposed to + + align:start position:0% +you get you suppose you're supposed to + + + align:start position:0% +you get you suppose you're supposed to +get that one day but to go and have two + + align:start position:0% +get that one day but to go and have two + + + align:start position:0% +get that one day but to go and have two +other full-time jobs + + align:start position:0% +other full-time jobs + + + align:start position:0% +other full-time jobs +and not only that but when you take a + + align:start position:0% +and not only that but when you take a + + + align:start position:0% +and not only that but when you take a +job there's some kind of form you sign + + align:start position:0% +job there's some kind of form you sign + + + align:start position:0% +job there's some kind of form you sign +about are you employed someplace else so + + align:start position:0% +about are you employed someplace else so + + + align:start position:0% +about are you employed someplace else so +they'll talk about conflicts of interest + + align:start position:0% +they'll talk about conflicts of interest + + + align:start position:0% +they'll talk about conflicts of interest +now right and + + align:start position:0% +now right and + + + align:start position:0% +now right and +for example uh here i'm on this + + align:start position:0% +for example uh here i'm on this + + + align:start position:0% +for example uh here i'm on this +sabbatical + + align:start position:0% +sabbatical + + + align:start position:0% +sabbatical +uh + + align:start position:0% +uh + + + align:start position:0% +uh +i'm asked to join the editorial board of + + align:start position:0% +i'm asked to join the editorial board of + + + align:start position:0% +i'm asked to join the editorial board of +this journal + + align:start position:0% +this journal + + + align:start position:0% +this journal +they say how should we list you howard + + align:start position:0% +they say how should we list you howard + + + align:start position:0% +they say how should we list you howard +or mit + + align:start position:0% +or mit + + + align:start position:0% +or mit +well i learned long time ago + + align:start position:0% +well i learned long time ago + + + align:start position:0% +well i learned long time ago +that if you are on sabbatical from + + align:start position:0% +that if you are on sabbatical from + + + align:start position:0% +that if you are on sabbatical from +howard + + align:start position:0% +howard + + + align:start position:0% +howard +to another institution that year you're + + align:start position:0% +to another institution that year you're + + + align:start position:0% +to another institution that year you're +at the other institution + + align:start position:0% +at the other institution + + + align:start position:0% +at the other institution +when you go back + + align:start position:0% +when you go back + + + align:start position:0% +when you go back +then you go back on the other one + + align:start position:0% +then you go back on the other one + + + align:start position:0% +then you go back on the other one +uh and and the the institution + + align:start position:0% +uh and and the the institution + + + align:start position:0% +uh and and the the institution +where you are uh on the sabbatical two + + align:start position:0% +where you are uh on the sabbatical two + + + align:start position:0% +where you are uh on the sabbatical two +uh will have some + + align:start position:0% +uh will have some + + + align:start position:0% +uh will have some +mean-spirited ideas if you uh don't give + + align:start position:0% +mean-spirited ideas if you uh don't give + + + align:start position:0% +mean-spirited ideas if you uh don't give +them the recognition and don't give them + + align:start position:0% +them the recognition and don't give them + + + align:start position:0% +them the recognition and don't give them +the prominent recognition + + align:start position:0% +the prominent recognition + + + align:start position:0% +the prominent recognition +and they don't even like it if they say + + align:start position:0% +and they don't even like it if they say + + + align:start position:0% +and they don't even like it if they say +mit slash howard + + align:start position:0% + + + + align:start position:0% + +so um so i might by dean and understand + + align:start position:0% +so um so i might by dean and understand + + + align:start position:0% +so um so i might by dean and understand +and i understand it what had oh i tell + + align:start position:0% +and i understand it what had oh i tell + + + align:start position:0% +and i understand it what had oh i tell +you what even set him up one day i + + align:start position:0% +you what even set him up one day i + + + align:start position:0% +you what even set him up one day i +published a paper and put down duke + + align:start position:0% +published a paper and put down duke + + + align:start position:0% +published a paper and put down duke +university + + align:start position:0% +university + + + align:start position:0% +university +he said wait + + align:start position:0% +he said wait + + + align:start position:0% +he said wait +are you going to submit that for uh for + + align:start position:0% +are you going to submit that for uh for + + + align:start position:0% +are you going to submit that for uh for +a raise + + align:start position:0% +a raise + + + align:start position:0% +a raise +so yeah i said well it's got duke + + align:start position:0% +so yeah i said well it's got duke + + + align:start position:0% +so yeah i said well it's got duke +university on there i said yeah + + align:start position:0% +university on there i said yeah + + + align:start position:0% +university on there i said yeah +sabbatical from howard university and + + align:start position:0% +sabbatical from howard university and + + + align:start position:0% +sabbatical from howard university and +here's my + + align:start position:0% +here's my + + + align:start position:0% +here's my +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so in other words there are some lower + + align:start position:0% +so in other words there are some lower + + + align:start position:0% +so in other words there are some lower +level issues + + align:start position:0% +level issues + + + align:start position:0% +level issues +that are not contested they have legal + + align:start position:0% +that are not contested they have legal + + + align:start position:0% +that are not contested they have legal +standing and this particular one with + + align:start position:0% +standing and this particular one with + + + align:start position:0% +standing and this particular one with +this professor was sort of on the cusp + + align:start position:0% + + + + align:start position:0% + +he found out that what they did in the + + align:start position:0% +he found out that what they did in the + + + align:start position:0% +he found out that what they did in the +end was they just all three of them + + align:start position:0% +end was they just all three of them + + + align:start position:0% +end was they just all three of them +all three universities fired him but + + align:start position:0% +all three universities fired him but + + + align:start position:0% +all three universities fired him but +they get what one of they gave him his + + align:start position:0% +they get what one of they gave him his + + + align:start position:0% +they get what one of they gave him his +return + + align:start position:0% + + + + align:start position:0% + +but uh it remains + + align:start position:0% +but uh it remains + + + align:start position:0% +but uh it remains +if + + align:start position:0% +if + + + align:start position:0% +if +you know the term uh skeletons in the + + align:start position:0% +you know the term uh skeletons in the + + + align:start position:0% +you know the term uh skeletons in the +closet + + align:start position:0% +closet + + + align:start position:0% +closet +where you've got a family and they're + + align:start position:0% +where you've got a family and they're + + + align:start position:0% +where you've got a family and they're +little things that everybody knows about + + align:start position:0% +little things that everybody knows about + + + align:start position:0% +little things that everybody knows about +but you don't want everybody else to + + align:start position:0% +but you don't want everybody else to + + + align:start position:0% +but you don't want everybody else to +know about + + align:start position:0% +know about + + + align:start position:0% +know about +in the academic profession he's a + + align:start position:0% +in the academic profession he's a + + + align:start position:0% +in the academic profession he's a +skeleton in our closet we + + align:start position:0% +skeleton in our closet we + + + align:start position:0% +skeleton in our closet we +really don't want other people to know + + align:start position:0% +really don't want other people to know + + + align:start position:0% +really don't want other people to know +about his case + + align:start position:0% +about his case + + + align:start position:0% +about his case +um + + align:start position:0% +um + + + align:start position:0% +um +the only thing about it that i am i + + align:start position:0% +the only thing about it that i am i + + + align:start position:0% +the only thing about it that i am i +suffer some bitterness over that + + align:start position:0% + + + + align:start position:0% + +uh and um + + align:start position:0% +uh and um + + + align:start position:0% +uh and um +i made one or two phone calls about it + + align:start position:0% +i made one or two phone calls about it + + + align:start position:0% +i made one or two phone calls about it +because i was a former student + + align:start position:0% +because i was a former student + + + align:start position:0% +because i was a former student +uh and i was bitter that there just + + align:start position:0% +uh and i was bitter that there just + + + align:start position:0% +uh and i was bitter that there just +didn't seem to be interest among + + align:start position:0% +didn't seem to be interest among + + + align:start position:0% +didn't seem to be interest among +students + + align:start position:0% +students + + + align:start position:0% +students +that here's a teacher + + align:start position:0% +that here's a teacher + + + align:start position:0% +that here's a teacher +that quote unquote just can't make it + + align:start position:0% +that quote unquote just can't make it + + + align:start position:0% +that quote unquote just can't make it +in his life + + align:start position:0% + + + + align:start position:0% + +so anyway but a whole lot of other + + align:start position:0% +so anyway but a whole lot of other + + + align:start position:0% +so anyway but a whole lot of other +issues got involved and they were nasty + + align:start position:0% +issues got involved and they were nasty + + + align:start position:0% +issues got involved and they were nasty +you know + + align:start position:0% +you know + + + align:start position:0% +you know +and people just want to sweep it under + + align:start position:0% +and people just want to sweep it under + + + align:start position:0% +and people just want to sweep it under +the table + + align:start position:0% + + + + align:start position:0% + +and but i think one thing they've done + + align:start position:0% +and but i think one thing they've done + + + align:start position:0% +and but i think one thing they've done +about that here at mit is + + align:start position:0% +about that here at mit is + + + align:start position:0% +about that here at mit is +they have a rank called a teaching + + align:start position:0% +they have a rank called a teaching + + + align:start position:0% +they have a rank called a teaching +professor + + align:start position:0% +professor + + + align:start position:0% +professor +i know that there's a person in esd + + align:start position:0% +i know that there's a person in esd + + + align:start position:0% +i know that there's a person in esd +that's called + + align:start position:0% +that's called + + + align:start position:0% +that's called +that has a + + align:start position:0% +that has a + + + align:start position:0% +that has a +rank of teaching yeah + + align:start position:0% +rank of teaching yeah + + + align:start position:0% +rank of teaching yeah +no + + align:start position:0% +no + + + align:start position:0% +no +it's called teaching professor + + align:start position:0% +it's called teaching professor + + + align:start position:0% +it's called teaching professor +uh it's chris mcgee + + align:start position:0% +uh it's chris mcgee + + + align:start position:0% +uh it's chris mcgee +no no he's called professor of the pro + + align:start position:0% +no no he's called professor of the pro + + + align:start position:0% +no no he's called professor of the pro +of the professional practice of + + align:start position:0% +of the professional practice of + + + align:start position:0% +of the professional practice of +engineering yeah + + align:start position:0% +engineering yeah + + + align:start position:0% +engineering yeah +but there's another one that is i think + + align:start position:0% +but there's another one that is i think + + + align:start position:0% +but there's another one that is i think +an esd that had well you all checked + + align:start position:0% +an esd that had well you all checked + + + align:start position:0% +an esd that had well you all checked +that + + align:start position:0% +that + + + align:start position:0% +that +out but anyway uh one way to get around + + align:start position:0% +out but anyway uh one way to get around + + + align:start position:0% +out but anyway uh one way to get around +it where uh at institutions that could + + align:start position:0% +it where uh at institutions that could + + + align:start position:0% +it where uh at institutions that could +afford to do it + + align:start position:0% +afford to do it + + + align:start position:0% +afford to do it +was to create uh teaching + + align:start position:0% +was to create uh teaching + + + align:start position:0% +was to create uh teaching +rank uh + + align:start position:0% +rank uh + + + align:start position:0% +rank uh +rank + + align:start position:0% + + + + align:start position:0% + +so you could have a person distinguished + + align:start position:0% +so you could have a person distinguished + + + align:start position:0% +so you could have a person distinguished +professor for teaching + + align:start position:0% +professor for teaching + + + align:start position:0% +professor for teaching +at some place and all they have to do is + + align:start position:0% +at some place and all they have to do is + + + align:start position:0% +at some place and all they have to do is +teach they can get their raises without + + align:start position:0% +teach they can get their raises without + + + align:start position:0% +teach they can get their raises without +submitting + + align:start position:0% +submitting + + + align:start position:0% +submitting +uh + + align:start position:0% +uh + + + align:start position:0% +uh +grants + + align:start position:0% + + + + align:start position:0% + +but uh that's as far as they've gone + + align:start position:0% +but uh that's as far as they've gone + + + align:start position:0% +but uh that's as far as they've gone +with that kind of thing but i'm just + + align:start position:0% +with that kind of thing but i'm just + + + align:start position:0% +with that kind of thing but i'm just +trying to say that these things are not + + align:start position:0% +trying to say that these things are not + + + align:start position:0% +trying to say that these things are not +secret + + align:start position:0% +secret + + + align:start position:0% +secret +you can document all of this + + align:start position:0% +you can document all of this + + + align:start position:0% +you can document all of this +but it still operates below the level of + + align:start position:0% +but it still operates below the level of + + + align:start position:0% +but it still operates below the level of +what i call the collective unconscious a + + align:start position:0% +what i call the collective unconscious a + + + align:start position:0% +what i call the collective unconscious a +collective consciousness nobody really + + align:start position:0% +collective consciousness nobody really + + + align:start position:0% +collective consciousness nobody really +wants to talk about it + + align:start position:0% +wants to talk about it + + + align:start position:0% +wants to talk about it +and underneath what they say and do + + align:start position:0% +and underneath what they say and do + + + align:start position:0% +and underneath what they say and do +will be some of that dust + + align:start position:0% +will be some of that dust + + + align:start position:0% +will be some of that dust +and you have that here with this curve + + align:start position:0% +and you have that here with this curve + + + align:start position:0% +and you have that here with this curve +okay uh let's sweat it out + + align:start position:0% +okay uh let's sweat it out + + + align:start position:0% +okay uh let's sweat it out +let's finish these six and uh + + align:start position:0% + + + + align:start position:0% + +statements only in an objective and + + align:start position:0% +statements only in an objective and + + + align:start position:0% +statements only in an objective and +truthful manner + + align:start position:0% +truthful manner + + + align:start position:0% +truthful manner +i'll tell you what that was about + + align:start position:0% + + + + align:start position:0% + +i'll tell you what that was about + + align:start position:0% +i'll tell you what that was about + + + align:start position:0% +i'll tell you what that was about +all of a sudden + + align:start position:0% +all of a sudden + + + align:start position:0% +all of a sudden +the ordinary engineer became someone + + align:start position:0% +the ordinary engineer became someone + + + align:start position:0% +the ordinary engineer became someone +that the big + + align:start position:0% +that the big + + + align:start position:0% +that the big +news media wanted to interview + + align:start position:0% + + + + align:start position:0% + +and + + align:start position:0% +and + + + align:start position:0% +and +uh that was that was terrifying + + align:start position:0% +uh that was that was terrifying + + + align:start position:0% +uh that was that was terrifying +you know it's terrifying for university + + align:start position:0% +you know it's terrifying for university + + + align:start position:0% +you know it's terrifying for university +uh + + align:start position:0% +uh + + + align:start position:0% +uh +all of a sudden some ordinary professor + + align:start position:0% + + + + align:start position:0% + +is on nightline or + + align:start position:0% +is on nightline or + + + align:start position:0% +is on nightline or +or i was interviewed by uh some the new + + align:start position:0% +or i was interviewed by uh some the new + + + align:start position:0% +or i was interviewed by uh some the new +york times you know stuff like that + + align:start position:0% +york times you know stuff like that + + + align:start position:0% +york times you know stuff like that +and + + align:start position:0% +and + + + align:start position:0% +and +um + + align:start position:0% +um + + + align:start position:0% +um +uh so they uh + + align:start position:0% +uh so they uh + + + align:start position:0% +uh so they uh +they + + align:start position:0% +they + + + align:start position:0% +they +they really uh struggled over who could + + align:start position:0% +they really uh struggled over who could + + + align:start position:0% +they really uh struggled over who could +speak for the company + + align:start position:0% +speak for the company + + + align:start position:0% +speak for the company +when there was a question of + + align:start position:0% + + + + align:start position:0% + +nuclear waste or something like that + + align:start position:0% +nuclear waste or something like that + + + align:start position:0% +nuclear waste or something like that +what can a person say + + align:start position:0% +what can a person say + + + align:start position:0% +what can a person say +and the lawyers got involved in that + + align:start position:0% + + + + align:start position:0% + +free speech + + align:start position:0% +free speech + + + align:start position:0% +free speech +not that they were defending it but they + + align:start position:0% +not that they were defending it but they + + + align:start position:0% +not that they were defending it but they +were trying to tell + + align:start position:0% +were trying to tell + + + align:start position:0% +were trying to tell +the presidents the ceos of corporations + + align:start position:0% +the presidents the ceos of corporations + + + align:start position:0% +the presidents the ceos of corporations +that you cannot suppress these employees + + align:start position:0% +that you cannot suppress these employees + + + align:start position:0% +that you cannot suppress these employees +because then the employee will take you + + align:start position:0% +because then the employee will take you + + + align:start position:0% +because then the employee will take you +to court and win big time + + align:start position:0% +to court and win big time + + + align:start position:0% +to court and win big time +right so what can you do so that was + + align:start position:0% +right so what can you do so that was + + + align:start position:0% +right so what can you do so that was +that issue there was uh really to cover + + align:start position:0% +that issue there was uh really to cover + + + align:start position:0% +that issue there was uh really to cover +ordinary people + + align:start position:0% +ordinary people + + + align:start position:0% +ordinary people +who now become celebrities + + align:start position:0% + + + + align:start position:0% + +and some of them let's face it some of + + align:start position:0% +and some of them let's face it some of + + + align:start position:0% +and some of them let's face it some of +them get drunk with being the celebrity + + align:start position:0% +them get drunk with being the celebrity + + + align:start position:0% +them get drunk with being the celebrity +you know what i mean + + align:start position:0% + + + + align:start position:0% + +look i mean let's think about it the + + align:start position:0% +look i mean let's think about it the + + + align:start position:0% +look i mean let's think about it the +ordinary things we've all been through + + align:start position:0% +ordinary things we've all been through + + + align:start position:0% +ordinary things we've all been through +this i've been through it + + align:start position:0% +this i've been through it + + + align:start position:0% +this i've been through it +you know when when the challenger went + + align:start position:0% +you know when when the challenger went + + + align:start position:0% +you know when when the challenger went +down howard university has a tv station + + align:start position:0% +down howard university has a tv station + + + align:start position:0% +down howard university has a tv station +so they had this call in program so they + + align:start position:0% +so they had this call in program so they + + + align:start position:0% +so they had this call in program so they +asked me to come in and take the calls + + align:start position:0% +asked me to come in and take the calls + + + align:start position:0% +asked me to come in and take the calls +and just before the calls come in i'm + + align:start position:0% +and just before the calls come in i'm + + + align:start position:0% +and just before the calls come in i'm +sitting down and they got a makeup + + align:start position:0% +sitting down and they got a makeup + + + align:start position:0% +sitting down and they got a makeup +artist + + align:start position:0% +artist + + + align:start position:0% +artist +so what you can let that stuff go to + + align:start position:0% +so what you can let that stuff go to + + + align:start position:0% +so what you can let that stuff go to +your head + + align:start position:0% + + + + align:start position:0% + +you know + + align:start position:0% +you know + + + align:start position:0% +you know +uh it was easy for me i just did my job + + align:start position:0% +uh it was easy for me i just did my job + + + align:start position:0% +uh it was easy for me i just did my job +and went back to the library of congress + + align:start position:0% +and went back to the library of congress + + + align:start position:0% +and went back to the library of congress +but + + align:start position:0% +but + + + align:start position:0% +but +some people + + align:start position:0% +some people + + + align:start position:0% +some people +that stuff goes to their heads and they + + align:start position:0% +that stuff goes to their heads and they + + + align:start position:0% +that stuff goes to their heads and they +start + + align:start position:0% + + + + align:start position:0% + +making life miserable for a lot of + + align:start position:0% +making life miserable for a lot of + + + align:start position:0% +making life miserable for a lot of +people unnecessarily + + align:start position:0% +people unnecessarily + + + align:start position:0% +people unnecessarily +so there was a lot of that underneath + + align:start position:0% +so there was a lot of that underneath + + + align:start position:0% +so there was a lot of that underneath +the surface that came to the surface + + align:start position:0% +the surface that came to the surface + + + align:start position:0% +the surface that came to the surface +everybody said well + + align:start position:0% +everybody said well + + + align:start position:0% +everybody said well +what they did was there's a term + + align:start position:0% +what they did was there's a term + + + align:start position:0% +what they did was there's a term +i don't know if it's a term of art + + align:start position:0% +i don't know if it's a term of art + + + align:start position:0% +i don't know if it's a term of art +but you're going to get it and it's + + align:start position:0% +but you're going to get it and it's + + + align:start position:0% +but you're going to get it and it's +called word smithing + + align:start position:0% +called word smithing + + + align:start position:0% +called word smithing +everybody knew what we had to do + + align:start position:0% +everybody knew what we had to do + + + align:start position:0% +everybody knew what we had to do +everybody agreed what we had to do still + + align:start position:0% +everybody agreed what we had to do still + + + align:start position:0% +everybody agreed what we had to do still +what words can we do right down here + + align:start position:0% +what words can we do right down here + + + align:start position:0% +what words can we do right down here +and so we so that particular one was a + + align:start position:0% +and so we so that particular one was a + + + align:start position:0% +and so we so that particular one was a +turned out for i i think it's fair to + + align:start position:0% +turned out for i i think it's fair to + + + align:start position:0% +turned out for i i think it's fair to +say for people who are writing codes of + + align:start position:0% +say for people who are writing codes of + + + align:start position:0% +say for people who are writing codes of +ethics + + align:start position:0% +ethics + + + align:start position:0% +ethics +to be a wordsmithing + + align:start position:0% +to be a wordsmithing + + + align:start position:0% +to be a wordsmithing +challenge + + align:start position:0% +challenge + + + align:start position:0% +challenge +particularly to get a lawyer in there + + align:start position:0% +particularly to get a lawyer in there + + + align:start position:0% +particularly to get a lawyer in there +so that we didn't go over the line but + + align:start position:0% +so that we didn't go over the line but + + + align:start position:0% +so that we didn't go over the line but +everybody sort of agreed on the + + align:start position:0% + + + + align:start position:0% + +principle is to present the company + + align:start position:0% +principle is to present the company + + + align:start position:0% +principle is to present the company +maybe in a more positive manner so you + + align:start position:0% +maybe in a more positive manner so you + + + align:start position:0% +maybe in a more positive manner so you +can't get an employee and get all the + + align:start position:0% +can't get an employee and get all the + + + align:start position:0% +can't get an employee and get all the +names + + align:start position:0% +names + + + align:start position:0% +names +and trash right maybe like underlined + + align:start position:0% +and trash right maybe like underlined + + + align:start position:0% +and trash right maybe like underlined +but it seems like that's not necessarily + + align:start position:0% +but it seems like that's not necessarily + + + align:start position:0% +but it seems like that's not necessarily +you could adhere to that and be truthful + + align:start position:0% +you could adhere to that and be truthful + + + align:start position:0% +you could adhere to that and be truthful +and maybe say something that + + align:start position:0% +and maybe say something that + + + align:start position:0% +and maybe say something that +you know management might not like and + + align:start position:0% +you know management might not like and + + + align:start position:0% +you know management might not like and +you are being + + align:start position:0% +you are being + + + align:start position:0% +you are being +objective and truthful right but maybe + + align:start position:0% +objective and truthful right but maybe + + + align:start position:0% +objective and truthful right but maybe +that is one of the other + + align:start position:0% +that is one of the other + + + align:start position:0% +that is one of the other +assumptions + + align:start position:0% + + + + align:start position:0% + +well definitely that's true i mean the + + align:start position:0% +well definitely that's true i mean the + + + align:start position:0% +well definitely that's true i mean the +way the way + + align:start position:0% +way the way + + + align:start position:0% +way the way +big organizations deal with that + + align:start position:0% +big organizations deal with that + + + align:start position:0% +big organizations deal with that +is + + align:start position:0% +is + + + align:start position:0% +is +when they do it + + align:start position:0% +when they do it + + + align:start position:0% +when they do it +is not to come out and tell everybody + + align:start position:0% +is not to come out and tell everybody + + + align:start position:0% +is not to come out and tell everybody +that they have to say things that put + + align:start position:0% +that they have to say things that put + + + align:start position:0% +that they have to say things that put +the company in the best light + + align:start position:0% +the company in the best light + + + align:start position:0% +the company in the best light +what they do is + + align:start position:0% +what they do is + + + align:start position:0% +what they do is +you're just not going to make it up the + + align:start position:0% +you're just not going to make it up the + + + align:start position:0% +you're just not going to make it up the +management level unless you really feel + + align:start position:0% +management level unless you really feel + + + align:start position:0% +management level unless you really feel +that way + + align:start position:0% +that way + + + align:start position:0% +that way +so it becomes an honest so + + align:start position:0% +so it becomes an honest so + + + align:start position:0% +so it becomes an honest so +so if you get a manager update a manager + + align:start position:0% +so if you get a manager update a manager + + + align:start position:0% +so if you get a manager update a manager +is not lying the manager is the person + + align:start position:0% +is not lying the manager is the person + + + align:start position:0% +is not lying the manager is the person +who was chosen because he or she really + + align:start position:0% +who was chosen because he or she really + + + align:start position:0% +who was chosen because he or she really +feels that way has that real outlook + + align:start position:0% +feels that way has that real outlook + + + align:start position:0% +feels that way has that real outlook +everybody believes and + + align:start position:0% +everybody believes and + + + align:start position:0% +everybody believes and +can portray it as something really + + align:start position:0% +can portray it as something really + + + align:start position:0% +can portray it as something really +something truthful and objective right + + align:start position:0% +something truthful and objective right + + + align:start position:0% +something truthful and objective right +somebody who feels differently is just + + align:start position:0% +somebody who feels differently is just + + + align:start position:0% +somebody who feels differently is just +not going to make it + + align:start position:0% +not going to make it + + + align:start position:0% +not going to make it +along those lines all right and you hope + + align:start position:0% +along those lines all right and you hope + + + align:start position:0% +along those lines all right and you hope +when i say you i mean the ceo + + align:start position:0% +when i say you i mean the ceo + + + align:start position:0% +when i say you i mean the ceo +hopes + + align:start position:0% +hopes + + + align:start position:0% +hopes +that somebody who is not in that line + + align:start position:0% +that somebody who is not in that line + + + align:start position:0% +that somebody who is not in that line +is not being interviewed and no the + + align:start position:0% +is not being interviewed and no the + + + align:start position:0% +is not being interviewed and no the +newspapers know + + align:start position:0% +newspapers know + + + align:start position:0% +newspapers know +the structure they know to get one + + align:start position:0% +the structure they know to get one + + + align:start position:0% +the structure they know to get one +person to say the party line they want + + align:start position:0% +person to say the party line they want + + + align:start position:0% +person to say the party line they want +to get another person to say something + + align:start position:0% +to get another person to say something + + + align:start position:0% +to get another person to say something +else and they play it against each other + + align:start position:0% +else and they play it against each other + + + align:start position:0% +else and they play it against each other +and it's hard to deal with + + align:start position:0% + + + + align:start position:0% + +uh what happens in the end i think is + + align:start position:0% +uh what happens in the end i think is + + + align:start position:0% +uh what happens in the end i think is +that uh if you have to do anything like + + align:start position:0% +that uh if you have to do anything like + + + align:start position:0% +that uh if you have to do anything like +that um + + align:start position:0% +that um + + + align:start position:0% +that um +and i've learned + + align:start position:0% +and i've learned + + + align:start position:0% +and i've learned +from experience + + align:start position:0% +from experience + + + align:start position:0% +from experience +uh is just to say that you are not a + + align:start position:0% +uh is just to say that you are not a + + + align:start position:0% +uh is just to say that you are not a +spokesman + + align:start position:0% +spokesman + + + align:start position:0% +spokesman +for your corporation + + align:start position:0% +for your corporation + + + align:start position:0% +for your corporation +you are an engineer there and you're + + align:start position:0% +you are an engineer there and you're + + + align:start position:0% +you are an engineer there and you're +speaking from the perspective of + + align:start position:0% +speaking from the perspective of + + + align:start position:0% +speaking from the perspective of +an engineer there and this is my + + align:start position:0% +an engineer there and this is my + + + align:start position:0% +an engineer there and this is my +perspective and my outlook and my + + align:start position:0% +perspective and my outlook and my + + + align:start position:0% +perspective and my outlook and my +experience but you don't drag + + align:start position:0% +experience but you don't drag + + + align:start position:0% +experience but you don't drag +you don't take credit for saying well at + + align:start position:0% +you don't take credit for saying well at + + + align:start position:0% +you don't take credit for saying well at +my company we + + align:start position:0% +my company we + + + align:start position:0% +my company we +you don't make statements like that + + align:start position:0% +you don't make statements like that + + + align:start position:0% +you don't make statements like that +somebody else can do it but you can't do + + align:start position:0% +somebody else can do it but you can't do + + + align:start position:0% +somebody else can do it but you can't do +it + + align:start position:0% +it + + + align:start position:0% +it +okay how many more we got + + align:start position:0% +okay how many more we got + + + align:start position:0% +okay how many more we got +three let's knock him out + + align:start position:0% +three let's knock him out + + + align:start position:0% +three let's knock him out +each employer or client + + align:start position:0% + + + + align:start position:0% + +yes + + align:start position:0% +yes + + + align:start position:0% +yes +what is a faithful agent + + align:start position:0% + + + + align:start position:0% + +that's that's uh we got that from the + + align:start position:0% +that's that's uh we got that from the + + + align:start position:0% +that's that's uh we got that from the +lawyers + + align:start position:0% + + + + align:start position:0% + +so in the specifics + + align:start position:0% +so in the specifics + + + align:start position:0% +so in the specifics +of practice it talks about disclosing + + align:start position:0% +of practice it talks about disclosing + + + align:start position:0% +of practice it talks about disclosing +all known or potential + + align:start position:0% + + + + align:start position:0% + +right + + align:start position:0% + + + + align:start position:0% + +not accepting compensation + + align:start position:0% +not accepting compensation + + + align:start position:0% +not accepting compensation +for more than one party for services on + + align:start position:0% +for more than one party for services on + + + align:start position:0% +for more than one party for services on +something + + align:start position:0% + + + + align:start position:0% + +not soliciting or accepting financial + + align:start position:0% +not soliciting or accepting financial + + + align:start position:0% +not soliciting or accepting financial +consideration from outside agents right + + align:start position:0% +consideration from outside agents right + + + align:start position:0% +consideration from outside agents right +so those are the particulars on this + + align:start position:0% +so those are the particulars on this + + + align:start position:0% +so those are the particulars on this +issue of faithful agent + + align:start position:0% +issue of faithful agent + + + align:start position:0% +issue of faithful agent +agency + + align:start position:0% +agency + + + align:start position:0% +agency +right + + align:start position:0% +right + + + align:start position:0% +right +so when you uh go work when you go to um + + align:start position:0% +so when you uh go work when you go to um + + + align:start position:0% +so when you uh go work when you go to um +um + + align:start position:0% + + + + align:start position:0% + +oh no i mean + + align:start position:0% +oh no i mean + + + align:start position:0% +oh no i mean +you you might go to + + align:start position:0% +you you might go to + + + align:start position:0% +you you might go to +to a contractor say i need another wing + + align:start position:0% +to a contractor say i need another wing + + + align:start position:0% +to a contractor say i need another wing +put on my house + + align:start position:0% + + + + align:start position:0% + +you want to believe that the contractor + + align:start position:0% +you want to believe that the contractor + + + align:start position:0% +you want to believe that the contractor +has your interest in + + align:start position:0% +has your interest in + + + align:start position:0% +has your interest in +paramount okay + + align:start position:0% +paramount okay + + + align:start position:0% +paramount okay +first + + align:start position:0% +first + + + align:start position:0% +first +and that the person is not saying well + + align:start position:0% +and that the person is not saying well + + + align:start position:0% +and that the person is not saying well +you know + + align:start position:0% + + + + align:start position:0% + +the + + align:start position:0% +the + + + align:start position:0% +the +real estate agency + + align:start position:0% +real estate agency + + + align:start position:0% +real estate agency +thinks that the market in this + + align:start position:0% +thinks that the market in this + + + align:start position:0% +thinks that the market in this +neighborhood + + align:start position:0% +neighborhood + + + align:start position:0% +neighborhood +will be higher + + align:start position:0% +will be higher + + + align:start position:0% +will be higher +if we don't have a whole lot of uh + + align:start position:0% +if we don't have a whole lot of uh + + + align:start position:0% +if we don't have a whole lot of uh +extensions put on these homes + + align:start position:0% +extensions put on these homes + + + align:start position:0% +extensions put on these homes +i don't know why they would say that but + + align:start position:0% +i don't know why they would say that but + + + align:start position:0% +i don't know why they would say that but +i'm making up a case + + align:start position:0% +i'm making up a case + + + align:start position:0% +i'm making up a case +and so they go to this meeting with the + + align:start position:0% +and so they go to this meeting with the + + + align:start position:0% +and so they go to this meeting with the +contractors and say well look uh + + align:start position:0% +contractors and say well look uh + + + align:start position:0% +contractors and say well look uh +it's not in our interest with having all + + align:start position:0% +it's not in our interest with having all + + + align:start position:0% +it's not in our interest with having all +of these things up so what the + + align:start position:0% +of these things up so what the + + + align:start position:0% +of these things up so what the +contractor does is come back let's say + + align:start position:0% +contractor does is come back let's say + + + align:start position:0% +contractor does is come back let's say +and says well you know quote you the + + align:start position:0% +and says well you know quote you the + + + align:start position:0% +and says well you know quote you the +highest prices on everything try to + + align:start position:0% +highest prices on everything try to + + + align:start position:0% +highest prices on everything try to +discourage you from doing it + + align:start position:0% +discourage you from doing it + + + align:start position:0% +discourage you from doing it +we don't want that okay the contract is + + align:start position:0% +we don't want that okay the contract is + + + align:start position:0% +we don't want that okay the contract is +supposed to say no matter what + + align:start position:0% +supposed to say no matter what + + + align:start position:0% +supposed to say no matter what +the other interests are i am your agent + + align:start position:0% +the other interests are i am your agent + + + align:start position:0% +the other interests are i am your agent +and + + align:start position:0% +and + + + align:start position:0% +and +uh you + + align:start position:0% +uh you + + + align:start position:0% +uh you +if you want this house thing put on here + + align:start position:0% +if you want this house thing put on here + + + align:start position:0% +if you want this house thing put on here +are the prices these are the best prices + + align:start position:0% +are the prices these are the best prices + + + align:start position:0% +are the prices these are the best prices +you don't need to have steel put in as a + + align:start position:0% +you don't need to have steel put in as a + + + align:start position:0% +you don't need to have steel put in as a +column for a one-story + + align:start position:0% +column for a one-story + + + align:start position:0% +column for a one-story +extension of your kitchen we can do that + + align:start position:0% +extension of your kitchen we can do that + + + align:start position:0% +extension of your kitchen we can do that +with a four five by four piece of + + align:start position:0% +with a four five by four piece of + + + align:start position:0% +with a four five by four piece of +wood all right + + align:start position:0% +wood all right + + + align:start position:0% +wood all right +uh and but you got to get a good piece + + align:start position:0% +uh and but you got to get a good piece + + + align:start position:0% +uh and but you got to get a good piece +of wood + + align:start position:0% +of wood + + + align:start position:0% +of wood +so this is the kind you get save + + align:start position:0% +so this is the kind you get save + + + align:start position:0% +so this is the kind you get save +yourself two or three thousand dollars + + align:start position:0% +yourself two or three thousand dollars + + + align:start position:0% +yourself two or three thousand dollars +okay so they don't want you playing that + + align:start position:0% +okay so they don't want you playing that + + + align:start position:0% +okay so they don't want you playing that +those kinds of games + + align:start position:0% +those kinds of games + + + align:start position:0% +those kinds of games +they want the client + + align:start position:0% +they want the client + + + align:start position:0% +they want the client +or whoever you're working for + + align:start position:0% +or whoever you're working for + + + align:start position:0% +or whoever you're working for +the good example is with the legal + + align:start position:0% +the good example is with the legal + + + align:start position:0% +the good example is with the legal +profession + + align:start position:0% +profession + + + align:start position:0% +profession +a lot of them believe that their client + + align:start position:0% +a lot of them believe that their client + + + align:start position:0% +a lot of them believe that their client +you know they're going to be agents for + + align:start position:0% +you know they're going to be agents for + + + align:start position:0% +you know they're going to be agents for +their client + + align:start position:0% +their client + + + align:start position:0% +their client +so i mean you could be + + align:start position:0% +so i mean you could be + + + align:start position:0% +so i mean you could be +a notorious killer if you're supposed to + + align:start position:0% +a notorious killer if you're supposed to + + + align:start position:0% +a notorious killer if you're supposed to +defend that client guess what you're + + align:start position:0% +defend that client guess what you're + + + align:start position:0% +defend that client guess what you're +supposed to do do your best + + align:start position:0% +supposed to do do your best + + + align:start position:0% +supposed to do do your best +to defend that client + + align:start position:0% + + + + align:start position:0% + +what's next + + align:start position:0% + + + + align:start position:0% + +that one is that is that what we would + + align:start position:0% +that one is that is that what we would + + + align:start position:0% +that one is that is that what we would +call it easy one give us some specifics + + align:start position:0% +call it easy one give us some specifics + + + align:start position:0% +call it easy one give us some specifics +what are the specific one or + + align:start position:0% +what are the specific one or + + + align:start position:0% +what are the specific one or +two qualifications + + align:start position:0% + + + + align:start position:0% + +[Laughter] + + align:start position:0% + + + + align:start position:0% + +we had a case at howard + + align:start position:0% +we had a case at howard + + + align:start position:0% +we had a case at howard +where a faculty member in engineering + + align:start position:0% +where a faculty member in engineering + + + align:start position:0% +where a faculty member in engineering +all this was a terrible case for other + + align:start position:0% +all this was a terrible case for other + + + align:start position:0% +all this was a terrible case for other +reasons that if if you want to know + + align:start position:0% +reasons that if if you want to know + + + align:start position:0% +reasons that if if you want to know +about we got time to go in + + align:start position:0% +about we got time to go in + + + align:start position:0% +about we got time to go in +but + + align:start position:0% +but + + + align:start position:0% +but +what he did was he submitted credentials + + align:start position:0% +what he did was he submitted credentials + + + align:start position:0% +what he did was he submitted credentials +of 200 publications + + align:start position:0% + + + + align:start position:0% + +adam nicely sit down + + align:start position:0% + + + + align:start position:0% + +and he came in from another university + + align:start position:0% +and he came in from another university + + + align:start position:0% +and he came in from another university +and they the department gave him uh + + align:start position:0% +and they the department gave him uh + + + align:start position:0% +and they the department gave him uh +full professional full professional 10 + + align:start position:0% +full professional full professional 10 + + + align:start position:0% +full professional full professional 10 +based on his presentation + + align:start position:0% +based on his presentation + + + align:start position:0% +based on his presentation +yeah + + align:start position:0% +yeah + + + align:start position:0% +yeah +mainly + + align:start position:0% +mainly + + + align:start position:0% +mainly + + align:start position:0% + + + align:start position:0% +okay + + align:start position:0% +okay + + + align:start position:0% +okay +uh there were some questions why he + + align:start position:0% +uh there were some questions why he + + + align:start position:0% +uh there were some questions why he +never made + + align:start position:0% + + + + align:start position:0% + +full at + + align:start position:0% +full at + + + align:start position:0% +full at +any of his previous places but + + align:start position:0% +any of his previous places but + + + align:start position:0% +any of his previous places but +that is + + align:start position:0% +that is + + + align:start position:0% +that is +usually uh answered by + + align:start position:0% +usually uh answered by + + + align:start position:0% +usually uh answered by +the real + + align:start position:0% +the real + + + align:start position:0% +the real +problem of the real case that maybe just + + align:start position:0% +problem of the real case that maybe just + + + align:start position:0% +problem of the real case that maybe just +didn't fit in + + align:start position:0% +didn't fit in + + + align:start position:0% +didn't fit in +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so i can think of some + + align:start position:0% +so i can think of some + + + align:start position:0% +so i can think of some +very talented professors + + align:start position:0% +very talented professors + + + align:start position:0% +very talented professors +that will not fit in at howard + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so we brought the professor down + + align:start position:0% +so we brought the professor down + + + align:start position:0% +so we brought the professor down +well he did something else + + align:start position:0% +well he did something else + + + align:start position:0% +well he did something else +that was totally irrelevant to that + + align:start position:0% +that was totally irrelevant to that + + + align:start position:0% +that was totally irrelevant to that +that + + align:start position:0% +that + + + align:start position:0% +that +everybody wanted to fire him for + + align:start position:0% +everybody wanted to fire him for + + + align:start position:0% +everybody wanted to fire him for +so + + align:start position:0% +so + + + align:start position:0% +so +the department is building up a case + + align:start position:0% +the department is building up a case + + + align:start position:0% +the department is building up a case +against him + + align:start position:0% + + + + align:start position:0% + +so they go back through his resume + + align:start position:0% + + + + align:start position:0% + +what they found out was + + align:start position:0% + + + + align:start position:0% + +that almost all of his publications + + align:start position:0% +that almost all of his publications + + + align:start position:0% +that almost all of his publications +were what you call commentaries + + align:start position:0% + + + + align:start position:0% + +so you publish an article + + align:start position:0% +so you publish an article + + + align:start position:0% +so you publish an article +that comes out + + align:start position:0% +that comes out + + + align:start position:0% +that comes out +and in many journals will allow + + align:start position:0% +and in many journals will allow + + + align:start position:0% +and in many journals will allow +a certain period of time like a year + + align:start position:0% +a certain period of time like a year + + + align:start position:0% +a certain period of time like a year +calendar year for the rest of us to say + + align:start position:0% +calendar year for the rest of us to say + + + align:start position:0% +calendar year for the rest of us to say +well you know i think that the equation + + align:start position:0% +well you know i think that the equation + + + align:start position:0% +well you know i think that the equation +3.2 + + align:start position:0% +3.2 + + + align:start position:0% +3.2 +in her report was incorrect + + align:start position:0% +in her report was incorrect + + + align:start position:0% +in her report was incorrect +it left out the square term you put in + + align:start position:0% +it left out the square term you put in + + + align:start position:0% +it left out the square term you put in +the square term and send it back and + + align:start position:0% +the square term and send it back and + + + align:start position:0% +the square term and send it back and +they publish it right along + + align:start position:0% +they publish it right along + + + align:start position:0% +they publish it right along +he had 200 commentary papers + + align:start position:0% + + + + align:start position:0% + +now we felt deceived + + align:start position:0% +now we felt deceived + + + align:start position:0% +now we felt deceived +we had made a contract with uh + + align:start position:0% +we had made a contract with uh + + + align:start position:0% +we had made a contract with uh +mephistopheles and stuff he + + align:start position:0% +mephistopheles and stuff he + + + align:start position:0% +mephistopheles and stuff he +we thought that + + align:start position:0% +we thought that + + + align:start position:0% +we thought that +he should have put in + + align:start position:0% +he should have put in + + + align:start position:0% +he should have put in +now i may comment do commentary papers + + align:start position:0% +now i may comment do commentary papers + + + align:start position:0% +now i may comment do commentary papers +but when i put all of the credentials + + align:start position:0% +but when i put all of the credentials + + + align:start position:0% +but when i put all of the credentials +down in for the commentary commentary i + + align:start position:0% +down in for the commentary commentary i + + + align:start position:0% +down in for the commentary commentary i +have a square bracket at the end it says + + align:start position:0% +have a square bracket at the end it says + + + align:start position:0% +have a square bracket at the end it says +commentary oh actually what i do in my + + align:start position:0% +commentary oh actually what i do in my + + + align:start position:0% +commentary oh actually what i do in my +resume i think you should look at my + + align:start position:0% +resume i think you should look at my + + + align:start position:0% +resume i think you should look at my +resume + + align:start position:0% +resume + + + align:start position:0% +resume +uh i got commentary paper i think right + + align:start position:0% +uh i got commentary paper i think right + + + align:start position:0% +uh i got commentary paper i think right +up + + align:start position:0% +up + + + align:start position:0% +up +after the title but i make sure that + + align:start position:0% +after the title but i make sure that + + + align:start position:0% +after the title but i make sure that +it's + + align:start position:0% +it's + + + align:start position:0% +it's +commentary paper now what i do to give a + + align:start position:0% +commentary paper now what i do to give a + + + align:start position:0% +commentary paper now what i do to give a +little bit of credit for myself + + align:start position:0% +little bit of credit for myself + + + align:start position:0% +little bit of credit for myself +is that the commentary papers i've + + align:start position:0% +is that the commentary papers i've + + + align:start position:0% +is that the commentary papers i've +written were what they call invited + + align:start position:0% +written were what they call invited + + + align:start position:0% +written were what they call invited +commentaries + + align:start position:0% +commentaries + + + align:start position:0% +commentaries +the editor will send me a copy of the + + align:start position:0% +the editor will send me a copy of the + + + align:start position:0% +the editor will send me a copy of the +paper and say look we need a commentary + + align:start position:0% +paper and say look we need a commentary + + + align:start position:0% +paper and say look we need a commentary +on it i'm not sitting there + + align:start position:0% +on it i'm not sitting there + + + align:start position:0% +on it i'm not sitting there +saying oh i think this equation 3.2 is + + align:start position:0% +saying oh i think this equation 3.2 is + + + align:start position:0% +saying oh i think this equation 3.2 is +wrong + + align:start position:0% +wrong + + + align:start position:0% +wrong +not that i wouldn't it just not has not + + align:start position:0% +not that i wouldn't it just not has not + + + align:start position:0% +not that i wouldn't it just not has not +happened + + align:start position:0% +happened + + + align:start position:0% +happened +for me in my career to do that so i will + + align:start position:0% +for me in my career to do that so i will + + + align:start position:0% +for me in my career to do that so i will +put invited commentary down there to + + align:start position:0% +put invited commentary down there to + + + align:start position:0% +put invited commentary down there to +give it a little more status + + align:start position:0% + + + + align:start position:0% + +but + + align:start position:0% +but + + + align:start position:0% +but +so that's a deception that that + + align:start position:0% +so that's a deception that that + + + align:start position:0% +so that's a deception that that +this was an engineer so i'm looking at + + align:start position:0% +this was an engineer so i'm looking at + + + align:start position:0% +this was an engineer so i'm looking at +it as not just academic profession but + + align:start position:0% +it as not just academic profession but + + + align:start position:0% +it as not just academic profession but +as engineering + + align:start position:0% +as engineering + + + align:start position:0% +as engineering +this guy deceived us as we were + + align:start position:0% +this guy deceived us as we were + + + align:start position:0% +this guy deceived us as we were +engineering colleagues + + align:start position:0% + + + + align:start position:0% + +another one that's interesting is + + align:start position:0% +another one that's interesting is + + + align:start position:0% +another one that's interesting is +engineers shall advise their clients or + + align:start position:0% +engineers shall advise their clients or + + + align:start position:0% +engineers shall advise their clients or +employers when they believe that a + + align:start position:0% +employers when they believe that a + + + align:start position:0% +employers when they believe that a +project will not be successful + + align:start position:0% + + + + align:start position:0% + +which i thought was an interesting one i + + align:start position:0% +which i thought was an interesting one i + + + align:start position:0% +which i thought was an interesting one i +mean it goes back to you know mandatory + + align:start position:0% +mean it goes back to you know mandatory + + + align:start position:0% +mean it goes back to you know mandatory +new engineer but it is the engineering + + align:start position:0% +new engineer but it is the engineering + + + align:start position:0% +new engineer but it is the engineering +job to say you know this is going to + + align:start position:0% +job to say you know this is going to + + + align:start position:0% +job to say you know this is going to +work + + align:start position:0% + + + + align:start position:0% + +it's also a + + align:start position:0% +it's also a + + + align:start position:0% +it's also a +scary situation to be in it + + align:start position:0% + + + + align:start position:0% + +so read it please + + align:start position:0% +so read it please + + + align:start position:0% +so read it please +well okay so the sticks can well + + align:start position:0% +well okay so the sticks can well + + + align:start position:0% +well okay so the sticks can well +because that could be really obvious no + + align:start position:0% +because that could be really obvious no + + + align:start position:0% +because that could be really obvious no +no + + align:start position:0% +no + + + align:start position:0% +no +so we just did the fifth cannon which is + + align:start position:0% +so we just did the fifth cannon which is + + + align:start position:0% +so we just did the fifth cannon which is +avoid deceptive acts and then the sixth + + align:start position:0% +avoid deceptive acts and then the sixth + + + align:start position:0% +avoid deceptive acts and then the sixth +cannon is + + align:start position:0% +cannon is + + + align:start position:0% +cannon is +conduct themselves honorably responsibly + + align:start position:0% +conduct themselves honorably responsibly + + + align:start position:0% +conduct themselves honorably responsibly +ethically and lawfully + + align:start position:0% +ethically and lawfully + + + align:start position:0% +ethically and lawfully +so as to enhance the honorable + + align:start position:0% +so as to enhance the honorable + + + align:start position:0% +so as to enhance the honorable +reputation and usefulness of the + + align:start position:0% +reputation and usefulness of the + + + align:start position:0% +reputation and usefulness of the +president + + align:start position:0% +president + + + align:start position:0% +president +yeah i always had an objection to that + + align:start position:0% +yeah i always had an objection to that + + + align:start position:0% +yeah i always had an objection to that +i don't have any obligation to enhance + + align:start position:0% +i don't have any obligation to enhance + + + align:start position:0% +i don't have any obligation to enhance +the profession + + align:start position:0% + + + + align:start position:0% + +and what you just brought up is under + + align:start position:0% +and what you just brought up is under + + + align:start position:0% +and what you just brought up is under +professional obligations so it says + + align:start position:0% +professional obligations so it says + + + align:start position:0% +professional obligations so it says +engineers shall advise their clients or + + align:start position:0% +engineers shall advise their clients or + + + align:start position:0% +engineers shall advise their clients or +employers when they believe a project + + align:start position:0% +employers when they believe a project + + + align:start position:0% +employers when they believe a project +will not be successful + + align:start position:0% +will not be successful + + + align:start position:0% +will not be successful +okay well and so far let me let me + + align:start position:0% +okay well and so far let me let me + + + align:start position:0% +okay well and so far let me let me +mention this that i i stand almost alone + + align:start position:0% +mention this that i i stand almost alone + + + align:start position:0% +mention this that i i stand almost alone +in this when it comes to enhancing the + + align:start position:0% +in this when it comes to enhancing the + + + align:start position:0% +in this when it comes to enhancing the +profession i don't believe that i have + + align:start position:0% +profession i don't believe that i have + + + align:start position:0% +profession i don't believe that i have +any obligation but i i have been + + align:start position:0% +any obligation but i i have been + + + align:start position:0% +any obligation but i i have been +overruled + + align:start position:0% + + + + align:start position:0% + +okay um + + align:start position:0% +okay um + + + align:start position:0% +okay um +i was thinking of a metaphor let me just + + align:start position:0% +i was thinking of a metaphor let me just + + + align:start position:0% +i was thinking of a metaphor let me just +put the argument down + + align:start position:0% +put the argument down + + + align:start position:0% +put the argument down +uh if if if if a profession + + align:start position:0% +uh if if if if a profession + + + align:start position:0% +uh if if if if a profession +is going to be honorable it has to be + + align:start position:0% +is going to be honorable it has to be + + + align:start position:0% +is going to be honorable it has to be +honorable without our making it + + align:start position:0% +honorable without our making it + + + align:start position:0% +honorable without our making it +honorable + + align:start position:0% +honorable + + + align:start position:0% +honorable +but i shouldn't have to do anything + + align:start position:0% +but i shouldn't have to do anything + + + align:start position:0% +but i shouldn't have to do anything +other + + align:start position:0% +other + + + align:start position:0% +other +than the minimum to make it honorable i + + align:start position:0% +than the minimum to make it honorable i + + + align:start position:0% +than the minimum to make it honorable i +don't going + + align:start position:0% +don't going + + + align:start position:0% +don't going +going beyond and saying i have some + + align:start position:0% +going beyond and saying i have some + + + align:start position:0% +going beyond and saying i have some +respect for the honor of the profession + + align:start position:0% +respect for the honor of the profession + + + align:start position:0% +respect for the honor of the profession +well that's + + align:start position:0% +well that's + + + align:start position:0% +well that's +that's sort of um circular if the + + align:start position:0% +that's sort of um circular if the + + + align:start position:0% +that's sort of um circular if the +profession + + align:start position:0% +profession + + + align:start position:0% +profession +is honorable it's got to earn it + + align:start position:0% +is honorable it's got to earn it + + + align:start position:0% +is honorable it's got to earn it +i shouldn't have to go around and do + + align:start position:0% +i shouldn't have to go around and do + + + align:start position:0% +i shouldn't have to go around and do +something extra to make it honorable + + align:start position:0% + + + + align:start position:0% + +and and + + align:start position:0% + + + + align:start position:0% + +so uh + + align:start position:0% + + + + align:start position:0% + +it should be honorable because of what + + align:start position:0% +it should be honorable because of what + + + align:start position:0% +it should be honorable because of what +it because of what it is + + align:start position:0% + + + + align:start position:0% + +following all of those things yeah + + align:start position:0% +following all of those things yeah + + + align:start position:0% +following all of those things yeah +make it honorable right + + align:start position:0% +make it honorable right + + + align:start position:0% +make it honorable right +i shouldn't have to go outside of that + + align:start position:0% +i shouldn't have to go outside of that + + + align:start position:0% +i shouldn't have to go outside of that +to enhance the honor + + align:start position:0% + + + + align:start position:0% + +because if you say that engineering is + + align:start position:0% +because if you say that engineering is + + + align:start position:0% +because if you say that engineering is +honorable then i should only have to do + + align:start position:0% +honorable then i should only have to do + + + align:start position:0% +honorable then i should only have to do +engineering and it will be honorable + + align:start position:0% +engineering and it will be honorable + + + align:start position:0% +engineering and it will be honorable +then you have this deceived me + + align:start position:0% +then you have this deceived me + + + align:start position:0% +then you have this deceived me +if i have to do more than that to make + + align:start position:0% +if i have to do more than that to make + + + align:start position:0% +if i have to do more than that to make +it honorable + + align:start position:0% +it honorable + + + align:start position:0% +it honorable +so i um + + align:start position:0% +so i um + + + align:start position:0% +so i um +i stand firm on my position but i'm the + + align:start position:0% +i stand firm on my position but i'm the + + + align:start position:0% +i stand firm on my position but i'm the +only one out there saying this + + align:start position:0% + + + + align:start position:0% + +yeah i guess i i think maybe that + + align:start position:0% +yeah i guess i i think maybe that + + + align:start position:0% +yeah i guess i i think maybe that +enhancing the honor or enhancing the + + align:start position:0% +enhancing the honor or enhancing the + + + align:start position:0% +enhancing the honor or enhancing the +public reputation + + align:start position:0% +public reputation + + + align:start position:0% +public reputation +enhancing it not just maintaining it + + align:start position:0% +enhancing it not just maintaining it + + + align:start position:0% +enhancing it not just maintaining it +it's more something that belongs in a + + align:start position:0% +it's more something that belongs in a + + + align:start position:0% +it's more something that belongs in a +recommendation a request + + align:start position:0% +recommendation a request + + + align:start position:0% +recommendation a request +i don't know like + + align:start position:0% +i don't know like + + + align:start position:0% +i don't know like +letter to colleagues + + align:start position:0% + + + + align:start position:0% + +the code of ethics should be the minimum + + align:start position:0% +the code of ethics should be the minimum + + + align:start position:0% +the code of ethics should be the minimum +yeah + + align:start position:0% +yeah + + + align:start position:0% +yeah +and the minimum should be good enough + + align:start position:0% + + + + align:start position:0% + +and anything that i do above the minimum + + align:start position:0% +and anything that i do above the minimum + + + align:start position:0% +and anything that i do above the minimum +is my business but not an obligation + + align:start position:0% + + + + align:start position:0% + +all of these words in ethics duty + + align:start position:0% +all of these words in ethics duty + + + align:start position:0% +all of these words in ethics duty +obligation they're talking about + + align:start position:0% +obligation they're talking about + + + align:start position:0% +obligation they're talking about +minimums + + align:start position:0% +minimums + + + align:start position:0% +minimums +if you go beyond that that's good but i + + align:start position:0% +if you go beyond that that's good but i + + + align:start position:0% +if you go beyond that that's good but i +don't have to go beyond + + align:start position:0% + + + + align:start position:0% + +yes and i was overruled + + align:start position:0% +yes and i was overruled + + + align:start position:0% +yes and i was overruled +everywhere + + align:start position:0% +everywhere + + + align:start position:0% +everywhere +uh + + align:start position:0% + + + + align:start position:0% + +okay uh we've got two more minutes uh i + + align:start position:0% +okay uh we've got two more minutes uh i + + + align:start position:0% +okay uh we've got two more minutes uh i +i + + align:start position:0% +i + + + align:start position:0% +i +i think that you've already picked up + + align:start position:0% +i think that you've already picked up + + + align:start position:0% +i think that you've already picked up +that the other codes of ethics do not + + align:start position:0% +that the other codes of ethics do not + + + align:start position:0% +that the other codes of ethics do not +differ substantially or if they do is + + align:start position:0% +differ substantially or if they do is + + + align:start position:0% +differ substantially or if they do is +mainly by abbreviation + + align:start position:0% +mainly by abbreviation + + + align:start position:0% +mainly by abbreviation +of this code + + align:start position:0% +of this code + + + align:start position:0% +of this code +the aaes code is uh + + align:start position:0% +the aaes code is uh + + + align:start position:0% +the aaes code is uh +is unique in as much as it + + align:start position:0% +is unique in as much as it + + + align:start position:0% +is unique in as much as it +stands it it offers it's it's called + + align:start position:0% +stands it it offers it's it's called + + + align:start position:0% +stands it it offers it's it's called +model + + align:start position:0% +model + + + align:start position:0% +model +guide or code + + align:start position:0% +guide or code + + + align:start position:0% +guide or code +and it tries to get + + align:start position:0% +and it tries to get + + + align:start position:0% +and it tries to get +some kind of coherence among all of the + + align:start position:0% +some kind of coherence among all of the + + + align:start position:0% +some kind of coherence among all of the +professional societies that belong to + + align:start position:0% +professional societies that belong to + + + align:start position:0% +professional societies that belong to +the aaes + + align:start position:0% +the aaes + + + align:start position:0% +the aaes +individuals don't belong + + align:start position:0% +individuals don't belong + + + align:start position:0% +individuals don't belong +okay + + align:start position:0% + + + + align:start position:0% + +just a model but but the the reason for + + align:start position:0% +just a model but but the the reason for + + + align:start position:0% +just a model but but the the reason for +it is that + + align:start position:0% +it is that + + + align:start position:0% +it is that +engineers were advised by high-level + + align:start position:0% +engineers were advised by high-level + + + align:start position:0% +engineers were advised by high-level +people in congress + + align:start position:0% +people in congress + + + align:start position:0% +people in congress +that engineering does not have + + align:start position:0% +that engineering does not have + + + align:start position:0% +that engineering does not have +uh force + + align:start position:0% +uh force + + + align:start position:0% +uh force +among + + align:start position:0% +among + + + align:start position:0% +among +uh in congress like the ama has + + align:start position:0% +uh in congress like the ama has + + + align:start position:0% +uh in congress like the ama has +because the ama can speak for the whole + + align:start position:0% +because the ama can speak for the whole + + + align:start position:0% +because the ama can speak for the whole +profession in engineering you got 10 12 + + align:start position:0% +profession in engineering you got 10 12 + + + align:start position:0% +profession in engineering you got 10 12 +different organizations saying different + + align:start position:0% +different organizations saying different + + + align:start position:0% +different organizations saying different +things + + align:start position:0% +things + + + align:start position:0% +things +so if you believe that engineering + + align:start position:0% +so if you believe that engineering + + + align:start position:0% +so if you believe that engineering +should have some force among + + align:start position:0% +should have some force among + + + align:start position:0% +should have some force among +congressional people lobby + + align:start position:0% +congressional people lobby + + + align:start position:0% +congressional people lobby +should have a lobbying + + align:start position:0% +should have a lobbying + + + align:start position:0% +should have a lobbying +uh dimension + + align:start position:0% +uh dimension + + + align:start position:0% +uh dimension +then try to make your code + + align:start position:0% +then try to make your code + + + align:start position:0% +then try to make your code +as consistent with the + + align:start position:0% +as consistent with the + + + align:start position:0% +as consistent with the +aaes model code as you can and that gets + + align:start position:0% +aaes model code as you can and that gets + + + align:start position:0% +aaes model code as you can and that gets +us closer to that other than that you're + + align:start position:0% +us closer to that other than that you're + + + align:start position:0% +us closer to that other than that you're +free to do whatever you want + + align:start position:0% + + + + align:start position:0% + +okay so we're going to have a special + + align:start position:0% +okay so we're going to have a special + + + align:start position:0% +okay so we're going to have a special +event coming up friday for those of us + + align:start position:0% +event coming up friday for those of us + + + align:start position:0% +event coming up friday for those of us +who want to go i want to go i'll be + + align:start position:0% +who want to go i want to go i'll be + + + align:start position:0% +who want to go i want to go i'll be +there + + align:start position:0% +there + + + align:start position:0% +there +and + + align:start position:0% +and + + + align:start position:0% +and +give us a little five minutes + + align:start position:0% + + + + align:start position:0% + +i hadn't thought about it + + align:start position:0% +i hadn't thought about it + + + align:start position:0% +i hadn't thought about it +will you email us + + align:start position:0% +will you email us + + + align:start position:0% +will you email us +yeah if i think of i won't be um if i + + align:start position:0% +yeah if i think of i won't be um if i + + + align:start position:0% +yeah if i think of i won't be um if i +think of something on + + align:start position:0% +think of something on + + + align:start position:0% +think of something on +sunday night i won't that'll be too late + + align:start position:0% +sunday night i won't that'll be too late + + + align:start position:0% +sunday night i won't that'll be too late +but + + align:start position:0% + + + + align:start position:0% + +no + + align:start position:0% +no + + + align:start position:0% +no +actually uh unless i get a brilliant + + align:start position:0% +actually uh unless i get a brilliant + + + align:start position:0% +actually uh unless i get a brilliant +idea which and i think my brain is not + + align:start position:0% +idea which and i think my brain is not + + + align:start position:0% +idea which and i think my brain is not +ready for any brilliant ideas right now + + align:start position:0% +ready for any brilliant ideas right now + + + align:start position:0% +ready for any brilliant ideas right now +unless i get a brilliant idea i'll just + + align:start position:0% +unless i get a brilliant idea i'll just + + + align:start position:0% +unless i get a brilliant idea i'll just +uh + + align:start position:0% +uh + + + align:start position:0% +uh +close out the discussion with codes of + + align:start position:0% +close out the discussion with codes of + + + align:start position:0% +close out the discussion with codes of +ethics + + align:start position:0% +ethics + + + align:start position:0% +ethics +and profession and professionalism + + align:start position:0% +and profession and professionalism + + + align:start position:0% +and profession and professionalism +can we talk about just + + align:start position:0% +can we talk about just + + + align:start position:0% +can we talk about just +in general the the basis of ethics + + align:start position:0% +in general the the basis of ethics + + + align:start position:0% +in general the the basis of ethics +because + + align:start position:0% +because + + + align:start position:0% +because +yeah i mean + + align:start position:0% +yeah i mean + + + align:start position:0% +yeah i mean +it's nice to just take the principle of + + align:start position:0% +it's nice to just take the principle of + + + align:start position:0% +it's nice to just take the principle of +approach and just say this but i think + + align:start position:0% +approach and just say this but i think + + + align:start position:0% +approach and just say this but i think +there are probably some arguments that + + align:start position:0% +there are probably some arguments that + + + align:start position:0% +there are probably some arguments that +can be made i mean use the example of a + + align:start position:0% +can be made i mean use the example of a + + + align:start position:0% +can be made i mean use the example of a +professor who again violate + + align:start position:0% +professor who again violate + + + align:start position:0% +professor who again violate +various + + align:start position:0% +various + + + align:start position:0% +various +aspects of a certain code right but did + + align:start position:0% +aspects of a certain code right but did + + + align:start position:0% +aspects of a certain code right but did +he really do anything + + align:start position:0% + + + + align:start position:0% + +by all means bring it up and + + align:start position:0% +by all means bring it up and + + + align:start position:0% +by all means bring it up and +oh i've got some stuff to say on that + + align:start position:0% +oh i've got some stuff to say on that + + + align:start position:0% +oh i've got some stuff to say on that +you know me by now i got something to + + align:start position:0% +you know me by now i got something to + + + align:start position:0% +you know me by now i got something to +say + + align:start position:0% +say + + + align:start position:0% +say +okay + + align:start position:0% +okay + + + align:start position:0% +okay +thank you \ No newline at end of file diff --git a/JYuMimF6bu0.txt b/JYuMimF6bu0.txt new file mode 100644 index 0000000000000000000000000000000000000000..5c31cd6f36666793828d80262fc79176d8326989 --- /dev/null +++ b/JYuMimF6bu0.txt @@ -0,0 +1,8099 @@ +align:start position:0% + +foreign + + align:start position:0% + + + + align:start position:0% + +okay so what we're going to do today is + + align:start position:0% +okay so what we're going to do today is + + + align:start position:0% +okay so what we're going to do today is +we're going to finish our coverage of + + align:start position:0% +we're going to finish our coverage of + + + align:start position:0% +we're going to finish our coverage of +statistical thermodynamics + + align:start position:0% +statistical thermodynamics + + + align:start position:0% +statistical thermodynamics +and + + align:start position:0% +and + + + align:start position:0% +and +um + + align:start position:0% +um + + + align:start position:0% +um +and then we're going to do a couple + + align:start position:0% +and then we're going to do a couple + + + align:start position:0% +and then we're going to do a couple +lectures + + align:start position:0% +lectures + + + align:start position:0% +lectures +starting Monday remember tomorrow's uh + + align:start position:0% +starting Monday remember tomorrow's uh + + + align:start position:0% +starting Monday remember tomorrow's uh +Friday's a holiday so we'll do a couple + + align:start position:0% +Friday's a holiday so we'll do a couple + + + align:start position:0% +Friday's a holiday so we'll do a couple +lectures uh starting Monday on + + align:start position:0% +lectures uh starting Monday on + + + align:start position:0% +lectures uh starting Monday on +reacting systems and that includes + + align:start position:0% +reacting systems and that includes + + + align:start position:0% +reacting systems and that includes +oxidation processes + + align:start position:0% +oxidation processes + + + align:start position:0% +oxidation processes +and that's mainly to half chapter 11 and + + align:start position:0% +and that's mainly to half chapter 11 and + + + align:start position:0% +and that's mainly to half chapter 11 and +then + + align:start position:0% +then + + + align:start position:0% +then +um and then that'll be it then we're + + align:start position:0% +um and then that'll be it then we're + + + align:start position:0% +um and then that'll be it then we're +going to have one more hour uh in on + + align:start position:0% +going to have one more hour uh in on + + + align:start position:0% +going to have one more hour uh in on +social and personal then we're going to + + align:start position:0% +social and personal then we're going to + + + align:start position:0% +social and personal then we're going to +have a game show which I don't know how + + align:start position:0% +have a game show which I don't know how + + + align:start position:0% +have a game show which I don't know how +to run a resume we're going to try it + + align:start position:0% +to run a resume we're going to try it + + + align:start position:0% +to run a resume we're going to try it +and + + align:start position:0% +and + + + align:start position:0% +and +um + + align:start position:0% +um + + + align:start position:0% +um +and then uh + + align:start position:0% +and then uh + + + align:start position:0% +and then uh +and then uh and then the the last exam + + align:start position:0% +and then uh and then the the last exam + + + align:start position:0% +and then uh and then the the last exam +which is non-cumulative okay so let's + + align:start position:0% +which is non-cumulative okay so let's + + + align:start position:0% +which is non-cumulative okay so let's +pick up where we left off + + align:start position:0% +pick up where we left off + + + align:start position:0% +pick up where we left off +Max entropy + + align:start position:0% + + + + align:start position:0% + +and the boltzmann distribution + + align:start position:0% + + + + align:start position:0% + +foreign + + align:start position:0% + + + + align:start position:0% + +continued from last lecture so + + align:start position:0% +continued from last lecture so + + + align:start position:0% +continued from last lecture so +I don't like to do this where I sort of + + align:start position:0% +I don't like to do this where I sort of + + + align:start position:0% +I don't like to do this where I sort of +continue with derivation and something + + align:start position:0% +continue with derivation and something + + + align:start position:0% +continue with derivation and something +across two lectures but um that's how it + + align:start position:0% +across two lectures but um that's how it + + + align:start position:0% +across two lectures but um that's how it +broke + + align:start position:0% + + + + align:start position:0% + +so from last time just um at a high + + align:start position:0% +so from last time just um at a high + + + align:start position:0% +so from last time just um at a high +level we decided that we wanted to + + align:start position:0% +level we decided that we wanted to + + + align:start position:0% +level we decided that we wanted to +optimize + + align:start position:0% + + + + align:start position:0% + +entropy + + align:start position:0% +entropy + + + align:start position:0% +entropy +for an isolated system + + align:start position:0% + + + + align:start position:0% + +and we had both an entropy formula so we + + align:start position:0% +and we had both an entropy formula so we + + + align:start position:0% +and we had both an entropy formula so we +could do some some math and we could uh + + align:start position:0% +could do some some math and we could uh + + + align:start position:0% +could do some some math and we could uh +write down the S equals zero + + align:start position:0% +write down the S equals zero + + + align:start position:0% +write down the S equals zero +subject + + align:start position:0% + + + + align:start position:0% + +to constraints + + align:start position:0% + + + + align:start position:0% + +and the constraints being conservation + + align:start position:0% +and the constraints being conservation + + + align:start position:0% +and the constraints being conservation +of energy + + align:start position:0% +of energy + + + align:start position:0% +of energy +and conservation of mass + + align:start position:0% + + + + align:start position:0% + +and we're going to do this using the + + align:start position:0% +and we're going to do this using the + + + align:start position:0% +and we're going to do this using the +method of LaGrange multipliers + + align:start position:0% + + + + align:start position:0% + +and we had two of them because we had + + align:start position:0% +and we had two of them because we had + + + align:start position:0% +and we had two of them because we had +two constraints + + align:start position:0% +two constraints + + + align:start position:0% +two constraints +Alpha and beta and we ended up with an + + align:start position:0% +Alpha and beta and we ended up with an + + + align:start position:0% +Alpha and beta and we ended up with an +expression like this + + align:start position:0% +expression like this + + + align:start position:0% +expression like this +some stuff + + align:start position:0% + + + + align:start position:0% + +so coefficient + + align:start position:0% +so coefficient + + + align:start position:0% +so coefficient +independent variables and in order to + + align:start position:0% +independent variables and in order to + + + align:start position:0% +independent variables and in order to +get our Max entropy condition I should + + align:start position:0% +get our Max entropy condition I should + + + align:start position:0% +get our Max entropy condition I should +say optimize entropy we had to set these + + align:start position:0% +say optimize entropy we had to set these + + + align:start position:0% +say optimize entropy we had to set these +coefficients to zero + + align:start position:0% + + + + align:start position:0% + +so there's a very sort of familiar + + align:start position:0% +so there's a very sort of familiar + + + align:start position:0% +so there's a very sort of familiar +thermodynamic thing that we did + + align:start position:0% +thermodynamic thing that we did + + + align:start position:0% +thermodynamic thing that we did +and what + + align:start position:0% +and what + + + align:start position:0% +and what +we determined + + align:start position:0% + + + + align:start position:0% + +the first multiplier by normalization + + align:start position:0% + + + + align:start position:0% + +so this is um where we left off where we + + align:start position:0% +so this is um where we left off where we + + + align:start position:0% +so this is um where we left off where we +left off was the following we had ni + + align:start position:0% +left off was the following we had ni + + + align:start position:0% +left off was the following we had ni +Over N total so this is a distribution + + align:start position:0% +Over N total so this is a distribution + + + align:start position:0% +Over N total so this is a distribution +function + + align:start position:0% +function + + + align:start position:0% +function +of fractional distributions of particles + + align:start position:0% +of fractional distributions of particles + + + align:start position:0% +of fractional distributions of particles +in state I + + align:start position:0% + + + + align:start position:0% + +normalized by the total number of + + align:start position:0% +normalized by the total number of + + + align:start position:0% +normalized by the total number of +particles and it was like this + + align:start position:0% +particles and it was like this + + + align:start position:0% +particles and it was like this +this multiplier beta as yet undetermined + + align:start position:0% +this multiplier beta as yet undetermined + + + align:start position:0% +this multiplier beta as yet undetermined +energy of State I + + align:start position:0% +energy of State I + + + align:start position:0% +energy of State I +normalized by Boltzmann's constant + + align:start position:0% +normalized by Boltzmann's constant + + + align:start position:0% +normalized by Boltzmann's constant +and that whole thing normalized by Q + + align:start position:0% +and that whole thing normalized by Q + + + align:start position:0% +and that whole thing normalized by Q +which was the partition function and + + align:start position:0% +which was the partition function and + + + align:start position:0% +which was the partition function and +this was the sum over all possible + + align:start position:0% +this was the sum over all possible + + + align:start position:0% +this was the sum over all possible +States e to the beta + + align:start position:0% +States e to the beta + + + align:start position:0% +States e to the beta +Epsilon I over Boltzmann's Constant and + + align:start position:0% +Epsilon I over Boltzmann's Constant and + + + align:start position:0% +Epsilon I over Boltzmann's Constant and +so this is where we left things + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +so now what we're going to do is we're + + align:start position:0% +so now what we're going to do is we're + + + align:start position:0% +so now what we're going to do is we're +going to determine beta + + align:start position:0% + + + + align:start position:0% + +we're going to determine beta by + + align:start position:0% +we're going to determine beta by + + + align:start position:0% +we're going to determine beta by +considering + + align:start position:0% + + + + align:start position:0% + +a microscopic + + align:start position:0% + + + + align:start position:0% + +reversible + + align:start position:0% + + + + align:start position:0% + +process + + align:start position:0% +process + + + align:start position:0% +process +where some of the particles change their + + align:start position:0% +where some of the particles change their + + + align:start position:0% +where some of the particles change their +statement + + align:start position:0% +statement + + + align:start position:0% +statement +so we're going to do is we're going to + + align:start position:0% +so we're going to do is we're going to + + + align:start position:0% +so we're going to do is we're going to +analyze the s for a process of some + + align:start position:0% +analyze the s for a process of some + + + align:start position:0% +analyze the s for a process of some +State changes + + align:start position:0% +State changes + + + align:start position:0% +State changes +I'm going to just go ahead and write + + align:start position:0% +I'm going to just go ahead and write + + + align:start position:0% +I'm going to just go ahead and write +down the equations that we've been using + + align:start position:0% +down the equations that we've been using + + + align:start position:0% +down the equations that we've been using +and developing for this the S equals log + + align:start position:0% +and developing for this the S equals log + + + align:start position:0% +and developing for this the S equals log +n of I over n total + + align:start position:0% + + + + align:start position:0% + +DN of I you can pull that from + + align:start position:0% +DN of I you can pull that from + + + align:start position:0% +DN of I you can pull that from +um + + align:start position:0% +um + + + align:start position:0% +um +you know the last two lectures but now + + align:start position:0% +you know the last two lectures but now + + + align:start position:0% +you know the last two lectures but now +we actually have an expression for this + + align:start position:0% +we actually have an expression for this + + + align:start position:0% +we actually have an expression for this +distribution so we're going to use that + + align:start position:0% +distribution so we're going to use that + + + align:start position:0% +distribution so we're going to use that +expression + + align:start position:0% +expression + + + align:start position:0% +expression +KB sum + + align:start position:0% +KB sum + + + align:start position:0% +KB sum +over I + + align:start position:0% +over I + + + align:start position:0% +over I +that distribution is e to the beta + + align:start position:0% +that distribution is e to the beta + + + align:start position:0% +that distribution is e to the beta +Epsilon I over boltzmann constant + + align:start position:0% +Epsilon I over boltzmann constant + + + align:start position:0% +Epsilon I over boltzmann constant +over Q + + align:start position:0% + + + + align:start position:0% + +then we have some logs of exponentials + + align:start position:0% +then we have some logs of exponentials + + + align:start position:0% +then we have some logs of exponentials +and things so we can simplify this a + + align:start position:0% +and things so we can simplify this a + + + align:start position:0% +and things so we can simplify this a +little bit and this equals + + align:start position:0% +little bit and this equals + + + align:start position:0% +little bit and this equals +minus beta + + align:start position:0% + + + + align:start position:0% + +sum over I + + align:start position:0% +sum over I + + + align:start position:0% +sum over I +Epsilon I + + align:start position:0% +Epsilon I + + + align:start position:0% +Epsilon I +d n of I + + align:start position:0% +d n of I + + + align:start position:0% +d n of I +Plus + + align:start position:0% +Plus + + + align:start position:0% +Plus +K beta + + align:start position:0% +K beta + + + align:start position:0% +K beta +log of Q + + align:start position:0% +log of Q + + + align:start position:0% +log of Q +sum over I + + align:start position:0% + + + + align:start position:0% + +d n of I + + align:start position:0% +d n of I + + + align:start position:0% +d n of I +and taking our definitions this equals + + align:start position:0% +and taking our definitions this equals + + + align:start position:0% +and taking our definitions this equals +minus beta + + align:start position:0% + + + + align:start position:0% + +d u + + align:start position:0% + + + + align:start position:0% + +Plus + + align:start position:0% +Plus + + + align:start position:0% +Plus +k b + + align:start position:0% +k b + + + align:start position:0% +k b +log of Q + + align:start position:0% + + + + align:start position:0% + +d n total + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +um first thing to note + + align:start position:0% +um first thing to note + + + align:start position:0% +um first thing to note +uh + + align:start position:0% +uh + + + align:start position:0% +uh +right this is zero by construction right + + align:start position:0% +right this is zero by construction right + + + align:start position:0% +right this is zero by construction right +this is the LaGrange multiplier uh + + align:start position:0% +this is the LaGrange multiplier uh + + + align:start position:0% +this is the LaGrange multiplier uh +working + + align:start position:0% +working + + + align:start position:0% +working +right because we we wanted DS to be zero + + align:start position:0% +right because we we wanted DS to be zero + + + align:start position:0% +right because we we wanted DS to be zero +under conditions where D U was zero and + + align:start position:0% +under conditions where D U was zero and + + + align:start position:0% +under conditions where D U was zero and +DN total were zero + + align:start position:0% +DN total were zero + + + align:start position:0% +DN total were zero +and we see that for this distribution + + align:start position:0% + + + + align:start position:0% + +it works out + + align:start position:0% +it works out + + + align:start position:0% +it works out +so the garage multiplier worked the + + align:start position:0% +so the garage multiplier worked the + + + align:start position:0% +so the garage multiplier worked the +method worked + + align:start position:0% +method worked + + + align:start position:0% +method worked +so I'm going to say 0 by Construction + + align:start position:0% + + + + align:start position:0% + +and if if you um I really like this + + align:start position:0% +and if if you um I really like this + + + align:start position:0% +and if if you um I really like this +orange pen but life is too short for + + align:start position:0% +orange pen but life is too short for + + + align:start position:0% +orange pen but life is too short for +fading Sharpies okay I I + + align:start position:0% +fading Sharpies okay I I + + + align:start position:0% +fading Sharpies okay I I +um + + align:start position:0% +um + + + align:start position:0% +um +so by construction this is zero now if + + align:start position:0% +so by construction this is zero now if + + + align:start position:0% +so by construction this is zero now if +you like you can convince yourself that + + align:start position:0% +you like you can convince yourself that + + + align:start position:0% +you like you can convince yourself that +if you have a different distribution + + align:start position:0% +if you have a different distribution + + + align:start position:0% +if you have a different distribution +function here if you have a different + + align:start position:0% +function here if you have a different + + + align:start position:0% +function here if you have a different +distribution function not this + + align:start position:0% +distribution function not this + + + align:start position:0% +distribution function not this +distribution let's say a flat + + align:start position:0% +distribution let's say a flat + + + align:start position:0% +distribution let's say a flat +distribution function a distribution + + align:start position:0% +distribution function a distribution + + + align:start position:0% +distribution function a distribution +function that doesn't depend on energy + + align:start position:0% +function that doesn't depend on energy + + + align:start position:0% +function that doesn't depend on energy +or has some other functional dependence + + align:start position:0% +or has some other functional dependence + + + align:start position:0% +or has some other functional dependence +of energy like I don't know what if some + + align:start position:0% +of energy like I don't know what if some + + + align:start position:0% +of energy like I don't know what if some +polynomial it could be anything in there + + align:start position:0% +polynomial it could be anything in there + + + align:start position:0% +polynomial it could be anything in there +you can show that in that case DS + + align:start position:0% +you can show that in that case DS + + + align:start position:0% +you can show that in that case DS +um will not be zero + + align:start position:0% +um will not be zero + + + align:start position:0% +um will not be zero +yeah so again LaGrange multiplier method + + align:start position:0% +yeah so again LaGrange multiplier method + + + align:start position:0% +yeah so again LaGrange multiplier method +works but here's here's the takeaway we + + align:start position:0% +works but here's here's the takeaway we + + + align:start position:0% +works but here's here's the takeaway we +want to compare this + + align:start position:0% + + + + align:start position:0% + +to what we have uh derived two months + + align:start position:0% +to what we have uh derived two months + + + align:start position:0% +to what we have uh derived two months +ago + + align:start position:0% +ago + + + align:start position:0% +ago +from the combined statement + + align:start position:0% +from the combined statement + + + align:start position:0% +from the combined statement +which is a DS equals 1 over t + + align:start position:0% + + + + align:start position:0% + +d u + + align:start position:0% +d u + + + align:start position:0% +d u +plus p over t + + align:start position:0% + + + + align:start position:0% + +DV + + align:start position:0% +DV + + + align:start position:0% +DV +minus mu over t + + align:start position:0% + + + + align:start position:0% + +b m + + align:start position:0% +b m + + + align:start position:0% +b m +and this is really the important thing + + align:start position:0% +and this is really the important thing + + + align:start position:0% +and this is really the important thing +here we are comparing + + align:start position:0% +here we are comparing + + + align:start position:0% +here we are comparing +the coefficients + + align:start position:0% +the coefficients + + + align:start position:0% +the coefficients +we're comparing the coefficients and if + + align:start position:0% +we're comparing the coefficients and if + + + align:start position:0% +we're comparing the coefficients and if +you remember + + align:start position:0% +you remember + + + align:start position:0% +you remember +this is almost like General strategy + + align:start position:0% +this is almost like General strategy + + + align:start position:0% +this is almost like General strategy +stuff + + align:start position:0% + + + + align:start position:0% + +if you compare coefficients you can buy + + align:start position:0% +if you compare coefficients you can buy + + + align:start position:0% +if you compare coefficients you can buy +inspection + + align:start position:0% + + + + align:start position:0% + +right set like coefficients to like + + align:start position:0% +right set like coefficients to like + + + align:start position:0% +right set like coefficients to like +so what is DS + + align:start position:0% + + + + align:start position:0% + +d u + + align:start position:0% + + + + align:start position:0% + +at fixed volume + + align:start position:0% +at fixed volume + + + align:start position:0% +at fixed volume +and fixed particle number + + align:start position:0% +and fixed particle number + + + align:start position:0% +and fixed particle number +well + + align:start position:0% +well + + + align:start position:0% +well +from our statistical method + + align:start position:0% +from our statistical method + + + align:start position:0% +from our statistical method +that's minus beta + + align:start position:0% +that's minus beta + + + align:start position:0% +that's minus beta +but from the classical method + + align:start position:0% +but from the classical method + + + align:start position:0% +but from the classical method +that's one over temperature + + align:start position:0% +that's one over temperature + + + align:start position:0% +that's one over temperature +and so we can simply conclude that beta + + align:start position:0% +and so we can simply conclude that beta + + + align:start position:0% +and so we can simply conclude that beta +equals minus one + + align:start position:0% +equals minus one + + + align:start position:0% +equals minus one +over temperature + + align:start position:0% + + + + align:start position:0% + +so now with that identified we have the + + align:start position:0% +so now with that identified we have the + + + align:start position:0% +so now with that identified we have the +Bolton distribution oh + + align:start position:0% +Bolton distribution oh + + + align:start position:0% +Bolton distribution oh +there's more paper so with + + align:start position:0% +there's more paper so with + + + align:start position:0% +there's more paper so with +beta equals minus 1 over temperature + + align:start position:0% +beta equals minus 1 over temperature + + + align:start position:0% +beta equals minus 1 over temperature +we have + + align:start position:0% + + + + align:start position:0% + +the both distribution + + align:start position:0% + + + + align:start position:0% + +number of particles in state I + + align:start position:0% +number of particles in state I + + + align:start position:0% +number of particles in state I +normalized by the total number of + + align:start position:0% +normalized by the total number of + + + align:start position:0% +normalized by the total number of +particles + + align:start position:0% +particles + + + align:start position:0% +particles +equals e to the minus E I + + align:start position:0% +equals e to the minus E I + + + align:start position:0% +equals e to the minus E I +over k b + + align:start position:0% +over k b + + + align:start position:0% +over k b +t + + align:start position:0% +t + + + align:start position:0% +t +normalized by the rotation function or + + align:start position:0% +normalized by the rotation function or + + + align:start position:0% +normalized by the rotation function or +the partition function + + align:start position:0% +the partition function + + + align:start position:0% +the partition function +equals the sum over all states e to the + + align:start position:0% +equals the sum over all states e to the + + + align:start position:0% +equals the sum over all states e to the +minus E I over k + + align:start position:0% +minus E I over k + + + align:start position:0% +minus E I over k +B + + align:start position:0% +B + + + align:start position:0% +B +t + + align:start position:0% +t + + + align:start position:0% +t +and this generally has a a falling + + align:start position:0% +and this generally has a a falling + + + align:start position:0% +and this generally has a a falling +exponential + + align:start position:0% +exponential + + + align:start position:0% +exponential +form + + align:start position:0% +form + + + align:start position:0% +form +with State energy + + align:start position:0% +with State energy + + + align:start position:0% +with State energy +so State energy e of I + + align:start position:0% +so State energy e of I + + + align:start position:0% +so State energy e of I +occupation n of I + + align:start position:0% +occupation n of I + + + align:start position:0% +occupation n of I +right it's a falling exponential + + align:start position:0% +right it's a falling exponential + + + align:start position:0% +right it's a falling exponential +function + + align:start position:0% + + + + align:start position:0% + +in words this is the distribution + + align:start position:0% + + + + align:start position:0% + +that maximizes entropy + + align:start position:0% + + + + align:start position:0% + +for an isolated system + + align:start position:0% + + + + align:start position:0% + +with + + align:start position:0% +with + + + align:start position:0% +with +and total particles + + align:start position:0% + + + + align:start position:0% + +distributed + + align:start position:0% + + + + align:start position:0% + +over + + align:start position:0% +over + + + align:start position:0% +over +States + + align:start position:0% + + + + align:start position:0% + +with fixed energy levels + + align:start position:0% + + + + align:start position:0% + +so unchanging energy levels + + align:start position:0% +so unchanging energy levels + + + align:start position:0% +so unchanging energy levels +according to + + align:start position:0% + + + + align:start position:0% + +that set of occupation numbers + + align:start position:0% +that set of occupation numbers + + + align:start position:0% +that set of occupation numbers +and what is maximum what is the state of + + align:start position:0% +and what is maximum what is the state of + + + align:start position:0% +and what is maximum what is the state of +Maximum entropy for an isolated system + + align:start position:0% +Maximum entropy for an isolated system + + + align:start position:0% +Maximum entropy for an isolated system +we have a name for that + + align:start position:0% +we have a name for that + + + align:start position:0% +we have a name for that +what's the state of Max entropy for an + + align:start position:0% +what's the state of Max entropy for an + + + align:start position:0% +what's the state of Max entropy for an +isolated system + + align:start position:0% + + + + align:start position:0% + +I think way back + + align:start position:0% +I think way back + + + align:start position:0% +I think way back +to late February even + + align:start position:0% + + + + align:start position:0% + +so this is an equilibrium distribution + + align:start position:0% +so this is an equilibrium distribution + + + align:start position:0% +so this is an equilibrium distribution +so we have an equilibrium distribution + + align:start position:0% +so we have an equilibrium distribution + + + align:start position:0% +so we have an equilibrium distribution +of single particle energy levels or + + align:start position:0% +of single particle energy levels or + + + align:start position:0% +of single particle energy levels or +single particle Energies + + align:start position:0% +single particle Energies + + + align:start position:0% +single particle Energies +and again + + align:start position:0% +and again + + + align:start position:0% +and again +um you know you knew this uh already but + + align:start position:0% +um you know you knew this uh already but + + + align:start position:0% +um you know you knew this uh already but +you know equilibrium does not mean + + align:start position:0% +you know equilibrium does not mean + + + align:start position:0% +you know equilibrium does not mean +everything is at the lowest energy all + + align:start position:0% +everything is at the lowest energy all + + + align:start position:0% +everything is at the lowest energy all +semester we've been exploring that + + align:start position:0% +semester we've been exploring that + + + align:start position:0% +semester we've been exploring that +consequence so you know if you were if + + align:start position:0% +consequence so you know if you were if + + + align:start position:0% +consequence so you know if you were if +you were at zero Kelvin + + align:start position:0% +you were at zero Kelvin + + + align:start position:0% +you were at zero Kelvin +if you're at zero Kelvin + + align:start position:0% +if you're at zero Kelvin + + + align:start position:0% +if you're at zero Kelvin +uh or you're a physicist which means + + align:start position:0% +uh or you're a physicist which means + + + align:start position:0% +uh or you're a physicist which means +you're a frigid heart you're a zero + + align:start position:0% +you're a frigid heart you're a zero + + + align:start position:0% +you're a frigid heart you're a zero +Kelvin this is your distribution + + align:start position:0% +Kelvin this is your distribution + + + align:start position:0% +Kelvin this is your distribution +function everything's piled up + + align:start position:0% +function everything's piled up + + + align:start position:0% +function everything's piled up +has zero energy + + align:start position:0% +has zero energy + + + align:start position:0% +has zero energy +right but at any real temperature + + align:start position:0% +right but at any real temperature + + + align:start position:0% +right but at any real temperature +you you can have you get energetic + + align:start position:0% +you you can have you get energetic + + + align:start position:0% +you you can have you get energetic +particles and you get them with a + + align:start position:0% +particles and you get them with a + + + align:start position:0% +particles and you get them with a +distribution function + + align:start position:0% + + + + align:start position:0% + +okay so a couple observations here the + + align:start position:0% +okay so a couple observations here the + + + align:start position:0% +okay so a couple observations here the +first observation is + + align:start position:0% +first observation is + + + align:start position:0% +first observation is +Maxwell distribution + + align:start position:0% + + + + align:start position:0% + +sorry it said boltzmann + + align:start position:0% + + + + align:start position:0% + +distribution + + align:start position:0% + + + + align:start position:0% + +and likelihood + + align:start position:0% + + + + align:start position:0% + +foreign + + align:start position:0% +foreign + + + align:start position:0% +foreign +likelihood + + align:start position:0% +likelihood + + + align:start position:0% +likelihood +um this is a stealth class on statistics + + align:start position:0% +um this is a stealth class on statistics + + + align:start position:0% +um this is a stealth class on statistics +right that's what statistical + + align:start position:0% +right that's what statistical + + + align:start position:0% +right that's what statistical +thermodynamics is it's like a stealth + + align:start position:0% +thermodynamics is it's like a stealth + + + align:start position:0% +thermodynamics is it's like a stealth +class on statistics so we'll ask + + align:start position:0% + + + + align:start position:0% + +how much less likely + + align:start position:0% + + + + align:start position:0% + +is it + + align:start position:0% + + + + align:start position:0% + +to find + + align:start position:0% +to find + + + align:start position:0% +to find +a particle + + align:start position:0% + + + + align:start position:0% + +in state + + align:start position:0% + + + + align:start position:0% + +with energy + + align:start position:0% + + + + align:start position:0% + +let's say + + align:start position:0% +let's say + + + align:start position:0% +let's say +e let's say e m + + align:start position:0% +e let's say e m + + + align:start position:0% +e let's say e m +that's an ugly Epsilon equals e l plus + + align:start position:0% +that's an ugly Epsilon equals e l plus + + + align:start position:0% +that's an ugly Epsilon equals e l plus +Delta e + + align:start position:0% +Delta e + + + align:start position:0% +Delta e +then + + align:start position:0% +then + + + align:start position:0% +then +in state + + align:start position:0% + + + + align:start position:0% + +with energy + + align:start position:0% + + + + align:start position:0% + +El + + align:start position:0% +El + + + align:start position:0% +El +F so that's a typical thing that you + + align:start position:0% +F so that's a typical thing that you + + + align:start position:0% +F so that's a typical thing that you +might need to analyze + + align:start position:0% +might need to analyze + + + align:start position:0% +might need to analyze +so let's see + + align:start position:0% +so let's see + + + align:start position:0% +so let's see +NM over NL right that's how you turn the + + align:start position:0% +NM over NL right that's how you turn the + + + align:start position:0% +NM over NL right that's how you turn the +word problem into a math problem how + + align:start position:0% +word problem into a math problem how + + + align:start position:0% +word problem into a math problem how +much less likely is it to find this + + align:start position:0% +much less likely is it to find this + + + align:start position:0% +much less likely is it to find this +distribution and this distribution or + + align:start position:0% +distribution and this distribution or + + + align:start position:0% +distribution and this distribution or +you know within within the equilibrium + + align:start position:0% +you know within within the equilibrium + + + align:start position:0% +you know within within the equilibrium +distribution how much smaller is this + + align:start position:0% +distribution how much smaller is this + + + align:start position:0% +distribution how much smaller is this +number than this number and um you'll + + align:start position:0% +number than this number and um you'll + + + align:start position:0% +number than this number and um you'll +find the + + align:start position:0% +find the + + + align:start position:0% +find the +the partition functions cancel out + + align:start position:0% +the partition functions cancel out + + + align:start position:0% +the partition functions cancel out +and you get the following + + align:start position:0% +and you get the following + + + align:start position:0% +and you get the following +El plus Delta e + + align:start position:0% +El plus Delta e + + + align:start position:0% +El plus Delta e +over K T over e + + align:start position:0% +over K T over e + + + align:start position:0% +over K T over e +to the minus e l + + align:start position:0% +to the minus e l + + + align:start position:0% +to the minus e l +over KT + + align:start position:0% +over KT + + + align:start position:0% +over KT +and so the e to the minus e l's cancel + + align:start position:0% +and so the e to the minus e l's cancel + + + align:start position:0% +and so the e to the minus e l's cancel +and you get e to the minus + + align:start position:0% +and you get e to the minus + + + align:start position:0% +and you get e to the minus +Delta e + + align:start position:0% + + + + align:start position:0% + +over KT + + align:start position:0% + + + + align:start position:0% + +okay so this depends + + align:start position:0% + + + + align:start position:0% + +depends on Delta Epsilon + + align:start position:0% +depends on Delta Epsilon + + + align:start position:0% +depends on Delta Epsilon +over KT clearly right + + align:start position:0% +over KT clearly right + + + align:start position:0% +over KT clearly right +it becomes less likely + + align:start position:0% + + + + align:start position:0% + +with + + align:start position:0% + + + + align:start position:0% + +with increasing energy splitting Delta e + + align:start position:0% +with increasing energy splitting Delta e + + + align:start position:0% +with increasing energy splitting Delta e +and it becomes + + align:start position:0% +and it becomes + + + align:start position:0% +and it becomes +more likely + + align:start position:0% + + + + align:start position:0% + +with temperature + + align:start position:0% + + + + align:start position:0% + +right okay so you're going to explore + + align:start position:0% +right okay so you're going to explore + + + align:start position:0% +right okay so you're going to explore +this a little bit uh on the pset and the + + align:start position:0% +this a little bit uh on the pset and the + + + align:start position:0% +this a little bit uh on the pset and the +context of um semiconductors + + align:start position:0% + + + + align:start position:0% + +another point + + align:start position:0% + + + + align:start position:0% + +the thermal energy + + align:start position:0% + + + + align:start position:0% + +right this quantity is really important + + align:start position:0% +right this quantity is really important + + + align:start position:0% +right this quantity is really important +it shows up in the Natural Sciences over + + align:start position:0% +it shows up in the Natural Sciences over + + + align:start position:0% +it shows up in the Natural Sciences over +and over and over again + + align:start position:0% +and over and over again + + + align:start position:0% +and over and over again +and we're starting to see why right the + + align:start position:0% +and we're starting to see why right the + + + align:start position:0% +and we're starting to see why right the +why is what we've just shown right + + align:start position:0% +why is what we've just shown right + + + align:start position:0% +why is what we've just shown right +um but the implications are really broad + + align:start position:0% +um but the implications are really broad + + + align:start position:0% +um but the implications are really broad +you're going to see this all over the + + align:start position:0% +you're going to see this all over the + + + align:start position:0% +you're going to see this all over the +place so let's remind ourselves with + + align:start position:0% +place so let's remind ourselves with + + + align:start position:0% +place so let's remind ourselves with +both swing constant is it's R Over N A + + align:start position:0% +both swing constant is it's R Over N A + + + align:start position:0% +both swing constant is it's R Over N A +oh that's finally RNA so it's it's the + + align:start position:0% +oh that's finally RNA so it's it's the + + + align:start position:0% +oh that's finally RNA so it's it's the +ideal gas constant divided by Avogadro's + + align:start position:0% +ideal gas constant divided by Avogadro's + + + align:start position:0% +ideal gas constant divided by Avogadro's +number we have that from before + + align:start position:0% +number we have that from before + + + align:start position:0% +number we have that from before +and this is something uh let's see + + align:start position:0% +and this is something uh let's see + + + align:start position:0% +and this is something uh let's see +1.380e to the minus 23 joules per Kelvin + + align:start position:0% +1.380e to the minus 23 joules per Kelvin + + + align:start position:0% +1.380e to the minus 23 joules per Kelvin +so it has units of entropy + + align:start position:0% +so it has units of entropy + + + align:start position:0% +so it has units of entropy +um but but that's not a number that I + + align:start position:0% +um but but that's not a number that I + + + align:start position:0% +um but but that's not a number that I +remember here's a number I do remember + + align:start position:0% +remember here's a number I do remember + + + align:start position:0% +remember here's a number I do remember +um + + align:start position:0% +um + + + align:start position:0% +um +and if you work on uh molecular systems + + align:start position:0% + + + + align:start position:0% + +or semiconductor systems + + align:start position:0% +or semiconductor systems + + + align:start position:0% +or semiconductor systems +um + + align:start position:0% +um + + + align:start position:0% +um +pretty much well gee a lot of systems + + align:start position:0% +pretty much well gee a lot of systems + + + align:start position:0% +pretty much well gee a lot of systems +that we work on in dmse this is a useful + + align:start position:0% +that we work on in dmse this is a useful + + + align:start position:0% +that we work on in dmse this is a useful +number to have memorized Bozeman's + + align:start position:0% +number to have memorized Bozeman's + + + align:start position:0% +number to have memorized Bozeman's +constant in units of EV for Kelvin 8.617 + + align:start position:0% +constant in units of EV for Kelvin 8.617 + + + align:start position:0% +constant in units of EV for Kelvin 8.617 +e minus five + + align:start position:0% +e minus five + + + align:start position:0% +e minus five +why on Earth would you memorize that + + align:start position:0% +why on Earth would you memorize that + + + align:start position:0% +why on Earth would you memorize that +it sets + + align:start position:0% +it sets + + + align:start position:0% +it sets +the energy scale + + align:start position:0% + + + + align:start position:0% + +for likely + + align:start position:0% +for likely + + + align:start position:0% +for likely +fluctuations + + align:start position:0% + + + + align:start position:0% + +right and we have + + align:start position:0% +right and we have + + + align:start position:0% +right and we have +all these words are have meaning right + + align:start position:0% +all these words are have meaning right + + + align:start position:0% +all these words are have meaning right +likely + + align:start position:0% +likely + + + align:start position:0% +likely +fluctuations right those words kind of + + align:start position:0% +fluctuations right those words kind of + + + align:start position:0% +fluctuations right those words kind of +carry a lot of weight so fluctuation + + align:start position:0% +carry a lot of weight so fluctuation + + + align:start position:0% +carry a lot of weight so fluctuation +single particle fluctuations with energy + + align:start position:0% +single particle fluctuations with energy + + + align:start position:0% +single particle fluctuations with energy +on the order of k b t r + + align:start position:0% +on the order of k b t r + + + align:start position:0% +on the order of k b t r +they're likely + + align:start position:0% +they're likely + + + align:start position:0% +they're likely +it's something you're going to find + + align:start position:0% +it's something you're going to find + + + align:start position:0% +it's something you're going to find +naturally occurring + + align:start position:0% +naturally occurring + + + align:start position:0% +naturally occurring +as opposed to fluctuations which are + + align:start position:0% +as opposed to fluctuations which are + + + align:start position:0% +as opposed to fluctuations which are +much much larger than the thermally + + align:start position:0% +much much larger than the thermally + + + align:start position:0% +much much larger than the thermally +energy + + align:start position:0% +energy + + + align:start position:0% +energy +those are unlikely + + align:start position:0% + + + + align:start position:0% + +we have all sorts of language for this + + align:start position:0% +we have all sorts of language for this + + + align:start position:0% +we have all sorts of language for this +that comes up in all sorts of contexts + + align:start position:0% +that comes up in all sorts of contexts + + + align:start position:0% +that comes up in all sorts of contexts +for example these fluctuations + + align:start position:0% +for example these fluctuations + + + align:start position:0% +for example these fluctuations +might be called thermally activated + + align:start position:0% +might be called thermally activated + + + align:start position:0% +might be called thermally activated +processes + + align:start position:0% + + + + align:start position:0% + +right you need a little bit of thermal + + align:start position:0% +right you need a little bit of thermal + + + align:start position:0% +right you need a little bit of thermal +energy to activate it + + align:start position:0% + + + + align:start position:0% + +all right so not only is this a number + + align:start position:0% +all right so not only is this a number + + + align:start position:0% +all right so not only is this a number +you should know but + + align:start position:0% +you should know but + + + align:start position:0% +you should know but +the thermal energy at room temperature + + align:start position:0% +the thermal energy at room temperature + + + align:start position:0% +the thermal energy at room temperature +is a number you should know + + align:start position:0% +is a number you should know + + + align:start position:0% +is a number you should know +a 298 Kelvin + + align:start position:0% +a 298 Kelvin + + + align:start position:0% +a 298 Kelvin +KBT equals well in joules it's not a + + align:start position:0% +KBT equals well in joules it's not a + + + align:start position:0% +KBT equals well in joules it's not a +number that I know because it's kind of + + align:start position:0% +number that I know because it's kind of + + + align:start position:0% +number that I know because it's kind of +unwieldy + + align:start position:0% +unwieldy + + + align:start position:0% +unwieldy +but in EV it is a number I know that's + + align:start position:0% +but in EV it is a number I know that's + + + align:start position:0% +but in EV it is a number I know that's +the Natural Energy scale of molecular + + align:start position:0% +the Natural Energy scale of molecular + + + align:start position:0% +the Natural Energy scale of molecular +processes so it's + + align:start position:0% +processes so it's + + + align:start position:0% +processes so it's +0.0257 electron volts or + + align:start position:0% +0.0257 electron volts or + + + align:start position:0% +0.0257 electron volts or +25.7 milli electron volts so + + align:start position:0% +25.7 milli electron volts so + + + align:start position:0% +25.7 milli electron volts so +approximately 25 ml electron volts is + + align:start position:0% +approximately 25 ml electron volts is + + + align:start position:0% +approximately 25 ml electron volts is +the thermal energy at room temperature + + align:start position:0% +the thermal energy at room temperature + + + align:start position:0% +the thermal energy at room temperature +so if you have a molecular system or an + + align:start position:0% +so if you have a molecular system or an + + + align:start position:0% +so if you have a molecular system or an +atomic system or an electronic system + + align:start position:0% +atomic system or an electronic system + + + align:start position:0% +atomic system or an electronic system +processes of that energy are likely to + + align:start position:0% +processes of that energy are likely to + + + align:start position:0% +processes of that energy are likely to +be happening spontaneously at ambient + + align:start position:0% +be happening spontaneously at ambient + + + align:start position:0% +be happening spontaneously at ambient +temperature + + align:start position:0% +temperature + + + align:start position:0% +temperature +processes which much much higher energy + + align:start position:0% +processes which much much higher energy + + + align:start position:0% +processes which much much higher energy +are not likely to be happening + + align:start position:0% +are not likely to be happening + + + align:start position:0% +are not likely to be happening +spontaneously at ambient temperature + + align:start position:0% +spontaneously at ambient temperature + + + align:start position:0% +spontaneously at ambient temperature +so you can see how powerful this is + + align:start position:0% +so you can see how powerful this is + + + align:start position:0% +so you can see how powerful this is +for example + + align:start position:0% +for example + + + align:start position:0% +for example +it's the foundation + + align:start position:0% + + + + align:start position:0% + +for + + align:start position:0% +for + + + align:start position:0% +for +the Arrhenius rate equation + + align:start position:0% + + + + align:start position:0% + +right the Arrhenius rate equation I'm + + align:start position:0% +right the Arrhenius rate equation I'm + + + align:start position:0% +right the Arrhenius rate equation I'm +going to use this the notation from a + + align:start position:0% +going to use this the notation from a + + + align:start position:0% +going to use this the notation from a +chemistry class here a rate k equals a + + align:start position:0% +chemistry class here a rate k equals a + + + align:start position:0% +chemistry class here a rate k equals a +pre-factor times e to the minus + + align:start position:0% +pre-factor times e to the minus + + + align:start position:0% +pre-factor times e to the minus +activation energy + + align:start position:0% +activation energy + + + align:start position:0% +activation energy +divided by Boltzmann's constant + + align:start position:0% +divided by Boltzmann's constant + + + align:start position:0% +divided by Boltzmann's constant +times temperature right now this this is + + align:start position:0% +times temperature right now this this is + + + align:start position:0% +times temperature right now this this is +um + + align:start position:0% +um + + + align:start position:0% +um +this is a rate + + align:start position:0% +this is a rate + + + align:start position:0% +this is a rate +percent activation energy + + align:start position:0% + + + + align:start position:0% + +right + + align:start position:0% +right + + + align:start position:0% +right +and activation energy and we are going + + align:start position:0% +and activation energy and we are going + + + align:start position:0% +and activation energy and we are going +to + + align:start position:0% +to + + + align:start position:0% +to +say hello to 3091 here + + align:start position:0% +say hello to 3091 here + + + align:start position:0% +say hello to 3091 here +they may have seen that there so just + + align:start position:0% +they may have seen that there so just + + + align:start position:0% +they may have seen that there so just +another context where you're going to + + align:start position:0% +another context where you're going to + + + align:start position:0% +another context where you're going to +see these exponentials and say why where + + align:start position:0% +see these exponentials and say why where + + + align:start position:0% +see these exponentials and say why where +right where'd that come from it comes + + align:start position:0% +right where'd that come from it comes + + + align:start position:0% +right where'd that come from it comes +from the spokesman distribution that we + + align:start position:0% +from the spokesman distribution that we + + + align:start position:0% +from the spokesman distribution that we +just arrived + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +more + + align:start position:0% + + + + align:start position:0% + +let's talk about + + align:start position:0% +let's talk about + + + align:start position:0% +let's talk about +um and for one side only this is a + + align:start position:0% +um and for one side only this is a + + + align:start position:0% +um and for one side only this is a +little dense but this is to help you + + align:start position:0% +little dense but this is to help you + + + align:start position:0% +little dense but this is to help you +with like with lad let's talk about the + + align:start position:0% +with like with lad let's talk about the + + + align:start position:0% +with like with lad let's talk about the +Maxwell Voltron distribution + + align:start position:0% + + + + align:start position:0% + +and I posted the wiki entry for this on + + align:start position:0% +and I posted the wiki entry for this on + + + align:start position:0% +and I posted the wiki entry for this on +on the on the website um so it's a good + + align:start position:0% +on the on the website um so it's a good + + + align:start position:0% +on the on the website um so it's a good +it's a good article to read and I think + + align:start position:0% +it's a good article to read and I think + + + align:start position:0% +it's a good article to read and I think +that the lab instructors refer to it as + + align:start position:0% +that the lab instructors refer to it as + + + align:start position:0% +that the lab instructors refer to it as +well so we're going to consider + + align:start position:0% + + + + align:start position:0% + +particles + + align:start position:0% + + + + align:start position:0% + +with energy + + align:start position:0% + + + + align:start position:0% + +kinetic energy right kinetic energy is + + align:start position:0% +kinetic energy right kinetic energy is + + + align:start position:0% +kinetic energy right kinetic energy is +momentum vector modulus squared + + align:start position:0% +momentum vector modulus squared + + + align:start position:0% +momentum vector modulus squared +divided by two times the mass that's + + align:start position:0% +divided by two times the mass that's + + + align:start position:0% +divided by two times the mass that's +kinetic energy of a particle of mass m + + align:start position:0% +kinetic energy of a particle of mass m + + + align:start position:0% +kinetic energy of a particle of mass m +and + + align:start position:0% +and + + + align:start position:0% +and +um we're in Three space so this is p x + + align:start position:0% +um we're in Three space so this is p x + + + align:start position:0% +um we're in Three space so this is p x +squared plus p y squared plus p z + + align:start position:0% +squared plus p y squared plus p z + + + align:start position:0% +squared plus p y squared plus p z +squared + + align:start position:0% +squared + + + align:start position:0% +squared +divided by 2m so that's the energy per + + align:start position:0% +divided by 2m so that's the energy per + + + align:start position:0% +divided by 2m so that's the energy per +particle in state of momentum p + + align:start position:0% + + + + align:start position:0% + +okay so what we want to do is we want to + + align:start position:0% +okay so what we want to do is we want to + + + align:start position:0% +okay so what we want to do is we want to +figure out the distribution of particles + + align:start position:0% +figure out the distribution of particles + + + align:start position:0% +figure out the distribution of particles +as a function of energy + + align:start position:0% + + + + align:start position:0% + +so this distribution + + align:start position:0% + + + + align:start position:0% + +distribution of uh distribution + + align:start position:0% +distribution of uh distribution + + + align:start position:0% +distribution of uh distribution +in energy + + align:start position:0% + + + + align:start position:0% + +I'll use f of B for consistency with + + align:start position:0% +I'll use f of B for consistency with + + + align:start position:0% +I'll use f of B for consistency with +Wikipedia + + align:start position:0% +Wikipedia + + + align:start position:0% +Wikipedia +it depends on both + + align:start position:0% + + + + align:start position:0% + +the Maxwell sorry the boltzmann + + align:start position:0% +the Maxwell sorry the boltzmann + + + align:start position:0% +the Maxwell sorry the boltzmann +distribution + + align:start position:0% + + + + align:start position:0% + +I had an error in my nuts there + + align:start position:0% +I had an error in my nuts there + + + align:start position:0% +I had an error in my nuts there +the Boston distribution + + align:start position:0% + + + + align:start position:0% + +n of I + + align:start position:0% +n of I + + + align:start position:0% +n of I +and for n total + + align:start position:0% +and for n total + + + align:start position:0% +and for n total +equals Q to the minus 1. + + align:start position:0% + + + + align:start position:0% + +exponent + + align:start position:0% +exponent + + + align:start position:0% +exponent +and it's going to be minus momentum + + align:start position:0% +and it's going to be minus momentum + + + align:start position:0% +and it's going to be minus momentum +of State I + + align:start position:0% +of State I + + + align:start position:0% +of State I +modulus squared over two + + align:start position:0% +modulus squared over two + + + align:start position:0% +modulus squared over two +m k t + + align:start position:0% +m k t + + + align:start position:0% +m k t +right so it depends on that they're both + + align:start position:0% +right so it depends on that they're both + + + align:start position:0% +right so it depends on that they're both +in distribution and also it depends on + + align:start position:0% +in distribution and also it depends on + + + align:start position:0% +in distribution and also it depends on +the + + align:start position:0% +the + + + align:start position:0% +the +density + + align:start position:0% + + + + align:start position:0% + +of states + + align:start position:0% + + + + align:start position:0% + +in momentum + + align:start position:0% + + + + align:start position:0% + +this concept of density of states is not + + align:start position:0% +this concept of density of states is not + + + align:start position:0% +this concept of density of states is not +something that we've covered + + align:start position:0% +something that we've covered + + + align:start position:0% +something that we've covered +in this class if you are in um O2 o29 + + align:start position:0% +in this class if you are in um O2 o29 + + + align:start position:0% +in this class if you are in um O2 o29 +you've discussed this you're going to + + align:start position:0% +you've discussed this you're going to + + + align:start position:0% +you've discussed this you're going to +see it in the in the in the lab but this + + align:start position:0% +see it in the in the in the lab but this + + + align:start position:0% +see it in the in the in the lab but this +really is a preview of what comes + + align:start position:0% +really is a preview of what comes + + + align:start position:0% +really is a preview of what comes +um in the fall when density of States + + align:start position:0% +um in the fall when density of States + + + align:start position:0% +um in the fall when density of States +becomes kind of uh + + align:start position:0% +becomes kind of uh + + + align:start position:0% +becomes kind of uh +um will be second nature for you in the + + align:start position:0% +um will be second nature for you in the + + + align:start position:0% +um will be second nature for you in the +context of quantum mechanics but density + + align:start position:0% +context of quantum mechanics but density + + + align:start position:0% +context of quantum mechanics but density +of States means well this is the + + align:start position:0% +of States means well this is the + + + align:start position:0% +of States means well this is the +bolstered distribution for a given State + + align:start position:0% +bolstered distribution for a given State + + + align:start position:0% +bolstered distribution for a given State +I + + align:start position:0% +I + + + align:start position:0% +I +with this energy + + align:start position:0% +with this energy + + + align:start position:0% +with this energy +how many such states are there + + align:start position:0% +how many such states are there + + + align:start position:0% +how many such states are there +right how many such states are there + + align:start position:0% + + + + align:start position:0% + +um so + + align:start position:0% + + + + align:start position:0% + +3D differential + + align:start position:0% +3D differential + + + align:start position:0% +3D differential +four equals four pi + + align:start position:0% +four equals four pi + + + align:start position:0% +four equals four pi +um + + align:start position:0% +um + + + align:start position:0% +um +P quantity squared DP + + align:start position:0% + + + + align:start position:0% + +to get the 4 Pi there because I + + align:start position:0% +to get the 4 Pi there because I + + + align:start position:0% +to get the 4 Pi there because I +integrated the spherical coordinates so + + align:start position:0% +integrated the spherical coordinates so + + + align:start position:0% +integrated the spherical coordinates so +four Pi stradians all around the sphere + + align:start position:0% +four Pi stradians all around the sphere + + + align:start position:0% +four Pi stradians all around the sphere +and that equals 4 Pi m + + align:start position:0% +and that equals 4 Pi m + + + align:start position:0% +and that equals 4 Pi m +root 2 m e + + align:start position:0% + + + + align:start position:0% + +d e + + align:start position:0% +d e + + + align:start position:0% +d e +so this is a distribution of states + + align:start position:0% +so this is a distribution of states + + + align:start position:0% +so this is a distribution of states +in energy e + + align:start position:0% +in energy e + + + align:start position:0% +in energy e +and you combine these two things you + + align:start position:0% +and you combine these two things you + + + align:start position:0% +and you combine these two things you +combine the density of states and the + + align:start position:0% +combine the density of states and the + + + align:start position:0% +combine the density of states and the +bolts and distribution and you get V + + align:start position:0% +bolts and distribution and you get V + + + align:start position:0% +bolts and distribution and you get V +Maxwell volts in distribution + + align:start position:0% +Maxwell volts in distribution + + + align:start position:0% +Maxwell volts in distribution +distribution of energetic particles + + align:start position:0% +distribution of energetic particles + + + align:start position:0% +distribution of energetic particles +zipping around on the kinetic energy + + align:start position:0% +zipping around on the kinetic energy + + + align:start position:0% +zipping around on the kinetic energy +included + + align:start position:0% +included + + + align:start position:0% +included +as a function of energy + + align:start position:0% +as a function of energy + + + align:start position:0% +as a function of energy +and it's two e over pi + + align:start position:0% + + + + align:start position:0% + +1 over KT to the three halves + + align:start position:0% + + + + align:start position:0% + +e to the minus E over k + + align:start position:0% +e to the minus E over k + + + align:start position:0% +e to the minus E over k +t + + align:start position:0% +t + + + align:start position:0% +t +so this is uh this is the the Maxwell + + align:start position:0% +so this is uh this is the the Maxwell + + + align:start position:0% +so this is uh this is the the Maxwell +boltzmann distribution + + align:start position:0% +boltzmann distribution + + + align:start position:0% +boltzmann distribution +and + + align:start position:0% + + + + align:start position:0% + +if you plot for example speed particle + + align:start position:0% +if you plot for example speed particle + + + align:start position:0% +if you plot for example speed particle +speed + + align:start position:0% + + + + align:start position:0% + +over probability + + align:start position:0% +over probability + + + align:start position:0% +over probability +right here's a low temperature + + align:start position:0% + + + + align:start position:0% + +you have something that's pretty sharply + + align:start position:0% +you have something that's pretty sharply + + + align:start position:0% +you have something that's pretty sharply +spiked here + + align:start position:0% + + + + align:start position:0% + +the intermediate temperature + + align:start position:0% + + + + align:start position:0% + +and then + + align:start position:0% +and then + + + align:start position:0% +and then +at high temperature + + align:start position:0% + + + + align:start position:0% + +this is a series of + + align:start position:0% +this is a series of + + + align:start position:0% +this is a series of +increasing temp + + align:start position:0% + + + + align:start position:0% + +okay and so this has this has the + + align:start position:0% +okay and so this has this has the + + + align:start position:0% +okay and so this has this has the +feature that + + align:start position:0% +feature that + + + align:start position:0% +feature that +um there are more particles that that go + + align:start position:0% +um there are more particles that that go + + + align:start position:0% +um there are more particles that that go +faster at higher temperature + + align:start position:0% +faster at higher temperature + + + align:start position:0% +faster at higher temperature +right you can see that coming from from + + align:start position:0% +right you can see that coming from from + + + align:start position:0% +right you can see that coming from from +this exponential + + align:start position:0% + + + + align:start position:0% + +and there's also a vanishingly small + + align:start position:0% +and there's also a vanishingly small + + + align:start position:0% +and there's also a vanishingly small +number of particles at zero speed + + align:start position:0% + + + + align:start position:0% + +right and there's going to be some + + align:start position:0% +right and there's going to be some + + + align:start position:0% +right and there's going to be some +mean speed + + align:start position:0% +mean speed + + + align:start position:0% +mean speed +that characterizes the distribution and + + align:start position:0% +that characterizes the distribution and + + + align:start position:0% +that characterizes the distribution and +that mean moves with temperature + + align:start position:0% +that mean moves with temperature + + + align:start position:0% +that mean moves with temperature +okay so I haven't derived this in detail + + align:start position:0% +okay so I haven't derived this in detail + + + align:start position:0% +okay so I haven't derived this in detail +because you know we haven't spent time + + align:start position:0% +because you know we haven't spent time + + + align:start position:0% +because you know we haven't spent time +on density of States but we're just + + align:start position:0% +on density of States but we're just + + + align:start position:0% +on density of States but we're just +exploring implications of that of that + + align:start position:0% +exploring implications of that of that + + + align:start position:0% +exploring implications of that of that +Baltimore distribution + + align:start position:0% +Baltimore distribution + + + align:start position:0% +Baltimore distribution +here's another implication + + align:start position:0% +here's another implication + + + align:start position:0% +here's another implication +okay + + align:start position:0% +okay + + + align:start position:0% +okay +um the last thing I want to cover which + + align:start position:0% +um the last thing I want to cover which + + + align:start position:0% +um the last thing I want to cover which +with only a couple slides to go is the + + align:start position:0% +with only a couple slides to go is the + + + align:start position:0% +with only a couple slides to go is the +concept of ensembles which is really + + align:start position:0% +concept of ensembles which is really + + + align:start position:0% +concept of ensembles which is really +just um + + align:start position:0% +just um + + + align:start position:0% +just um +3030 Readiness right we're doing this + + align:start position:0% +3030 Readiness right we're doing this + + + align:start position:0% +3030 Readiness right we're doing this +just to show you that you know some + + align:start position:0% +just to show you that you know some + + + align:start position:0% +just to show you that you know some +Concepts which you're not going to use + + align:start position:0% +Concepts which you're not going to use + + + align:start position:0% +Concepts which you're not going to use +in this class but + + align:start position:0% +in this class but + + + align:start position:0% +in this class but +um you will use in in kinetics and + + align:start position:0% +um you will use in in kinetics and + + + align:start position:0% +um you will use in in kinetics and +macrostructure in the fall so before I + + align:start position:0% +macrostructure in the fall so before I + + + align:start position:0% +macrostructure in the fall so before I +move on to discuss ensembles I want to + + align:start position:0% +move on to discuss ensembles I want to + + + align:start position:0% +move on to discuss ensembles I want to +pause and take questions on the + + align:start position:0% +pause and take questions on the + + + align:start position:0% +pause and take questions on the +boltzmann distribution or Maxwell + + align:start position:0% +boltzmann distribution or Maxwell + + + align:start position:0% +boltzmann distribution or Maxwell +boltzmann or anything else Arenas or + + align:start position:0% +boltzmann or anything else Arenas or + + + align:start position:0% +boltzmann or anything else Arenas or +anything else related + + align:start position:0% +anything else related + + + align:start position:0% +anything else related +who's seen the boltzmann distribution or + + align:start position:0% +who's seen the boltzmann distribution or + + + align:start position:0% +who's seen the boltzmann distribution or +this + + align:start position:0% +this + + + align:start position:0% +this +okay who's seeing the Arrhenius rate law + + align:start position:0% +okay who's seeing the Arrhenius rate law + + + align:start position:0% +okay who's seeing the Arrhenius rate law +there's not a lot of participation on + + align:start position:0% +there's not a lot of participation on + + + align:start position:0% +there's not a lot of participation on +zoom and so I understand that + + align:start position:0% +zoom and so I understand that + + + align:start position:0% +zoom and so I understand that +um I'm guessing that a large number of + + align:start position:0% +um I'm guessing that a large number of + + + align:start position:0% +um I'm guessing that a large number of +people raise their hands + + align:start position:0% +people raise their hands + + + align:start position:0% +people raise their hands +um and then if I asked you about the + + align:start position:0% +um and then if I asked you about the + + + align:start position:0% +um and then if I asked you about the +Bolton distribution to be a small number + + align:start position:0% +Bolton distribution to be a small number + + + align:start position:0% +Bolton distribution to be a small number +and if I ask you about the Maxwell + + align:start position:0% +and if I ask you about the Maxwell + + + align:start position:0% +and if I ask you about the Maxwell +bullets and distribution it'd probably + + align:start position:0% +bullets and distribution it'd probably + + + align:start position:0% +bullets and distribution it'd probably +be an even smaller number + + align:start position:0% + + + + align:start position:0% + +but I bet that everyone's seen something + + align:start position:0% +but I bet that everyone's seen something + + + align:start position:0% +but I bet that everyone's seen something +of this form somewhere before so I hope + + align:start position:0% +of this form somewhere before so I hope + + + align:start position:0% +of this form somewhere before so I hope +it's a little bit satisfying for you to + + align:start position:0% +it's a little bit satisfying for you to + + + align:start position:0% +it's a little bit satisfying for you to +see + + align:start position:0% +see + + + align:start position:0% +see +where it comes from right and to + + align:start position:0% +where it comes from right and to + + + align:start position:0% +where it comes from right and to +understand the principles behind it + + align:start position:0% +understand the principles behind it + + + align:start position:0% +understand the principles behind it +maximum entropy + + align:start position:0% +maximum entropy + + + align:start position:0% +maximum entropy +okay so let's talk about ensembles + + align:start position:0% + + + + align:start position:0% + +ensembles are + + align:start position:0% +ensembles are + + + align:start position:0% +ensembles are +what I look up a different definition of + + align:start position:0% +what I look up a different definition of + + + align:start position:0% +what I look up a different definition of +Cambridge Dictionary it says a group of + + align:start position:0% +Cambridge Dictionary it says a group of + + + align:start position:0% +Cambridge Dictionary it says a group of +things + + align:start position:0% + + + + align:start position:0% + +are people + + align:start position:0% + + + + align:start position:0% + +acting together + + align:start position:0% + + + + align:start position:0% + +or taken as a whole + + align:start position:0% + + + + align:start position:0% + +so this is um + + align:start position:0% +so this is um + + + align:start position:0% +so this is um +you know a concept and and we're going + + align:start position:0% +you know a concept and and we're going + + + align:start position:0% +you know a concept and and we're going +to use it a lot in statistical + + align:start position:0% +to use it a lot in statistical + + + align:start position:0% +to use it a lot in statistical +thermodynamics if not necessarily in + + align:start position:0% +thermodynamics if not necessarily in + + + align:start position:0% +thermodynamics if not necessarily in +this class but you know like I said this + + align:start position:0% +this class but you know like I said this + + + align:start position:0% +this class but you know like I said this +is 3030 Readiness here + + align:start position:0% + + + + align:start position:0% + +all right if I didn't tell you about + + align:start position:0% +all right if I didn't tell you about + + + align:start position:0% +all right if I didn't tell you about +this again trouble with Professor who + + align:start position:0% +this again trouble with Professor who + + + align:start position:0% +this again trouble with Professor who +all right so we're going to start with + + align:start position:0% +all right so we're going to start with + + + align:start position:0% +all right so we're going to start with +the micro canonical Ensemble and this is + + align:start position:0% +the micro canonical Ensemble and this is + + + align:start position:0% +the micro canonical Ensemble and this is +something that you've seen before micro + + align:start position:0% +something that you've seen before micro + + + align:start position:0% +something that you've seen before micro +canonical + + align:start position:0% + + + + align:start position:0% + +something called the micro canonical + + align:start position:0% +something called the micro canonical + + + align:start position:0% +something called the micro canonical +ensemble + + align:start position:0% + + + + align:start position:0% + +this is the set + + align:start position:0% +this is the set + + + align:start position:0% +this is the set +of all possible + + align:start position:0% + + + + align:start position:0% + +microstates + + align:start position:0% + + + + align:start position:0% + +so the type of stuff that we've been + + align:start position:0% +so the type of stuff that we've been + + + align:start position:0% +so the type of stuff that we've been +doing instead of all possible + + align:start position:0% +doing instead of all possible + + + align:start position:0% +doing instead of all possible +microstates + + align:start position:0% + + + + align:start position:0% + +of a system + + align:start position:0% + + + + align:start position:0% + +with fixed + + align:start position:0% + + + + align:start position:0% + +energy + + align:start position:0% +energy + + + align:start position:0% +energy +volume + + align:start position:0% +volume + + + align:start position:0% +volume +and particle number + + align:start position:0% +and particle number + + + align:start position:0% +and particle number +right so a system with fixed energy + + align:start position:0% +right so a system with fixed energy + + + align:start position:0% +right so a system with fixed energy +volume and particle number that is um + + align:start position:0% +volume and particle number that is um + + + align:start position:0% +volume and particle number that is um +that's an isolated system + + align:start position:0% + + + + align:start position:0% + +right for an isolated system equilibrium + + align:start position:0% +right for an isolated system equilibrium + + + align:start position:0% +right for an isolated system equilibrium +is state of Max entropy that's what we + + align:start position:0% +is state of Max entropy that's what we + + + align:start position:0% +is state of Max entropy that's what we +were just analyzing + + align:start position:0% +were just analyzing + + + align:start position:0% +were just analyzing +all right so this thing which we've been + + align:start position:0% +all right so this thing which we've been + + + align:start position:0% +all right so this thing which we've been +doing for the last two and a half + + align:start position:0% +doing for the last two and a half + + + align:start position:0% +doing for the last two and a half +lectures this is called the micro + + align:start position:0% +lectures this is called the micro + + + align:start position:0% +lectures this is called the micro +canonical Ensemble just gave a name to + + align:start position:0% +canonical Ensemble just gave a name to + + + align:start position:0% +canonical Ensemble just gave a name to +it and so the partition function that + + align:start position:0% +it and so the partition function that + + + align:start position:0% +it and so the partition function that +we've been analyzing is actually better + + align:start position:0% +we've been analyzing is actually better + + + align:start position:0% +we've been analyzing is actually better +known as a micro + + align:start position:0% +known as a micro + + + align:start position:0% +known as a micro +canonical + + align:start position:0% +canonical + + + align:start position:0% +canonical +partition function + + align:start position:0% + + + + align:start position:0% + +normally written as Q as we've been + + align:start position:0% +normally written as Q as we've been + + + align:start position:0% +normally written as Q as we've been +doing + + align:start position:0% +doing + + + align:start position:0% +doing +and it is a sum over + + align:start position:0% +and it is a sum over + + + align:start position:0% +and it is a sum over +single particle energy states + + align:start position:0% + + + + align:start position:0% + +some + + align:start position:0% + + + + align:start position:0% + +Over All + + align:start position:0% +Over All + + + align:start position:0% +Over All +possible + + align:start position:0% + + + + align:start position:0% + +single + + align:start position:0% + + + + align:start position:0% + +particle States + + align:start position:0% + + + + align:start position:0% + +and we know that we're at equilibrium + + align:start position:0% +and we know that we're at equilibrium + + + align:start position:0% +and we know that we're at equilibrium +equilibrium with s + + align:start position:0% +equilibrium with s + + + align:start position:0% +equilibrium with s +maximized + + align:start position:0% + + + + align:start position:0% + +for what + + align:start position:0% +for what + + + align:start position:0% +for what +for the Boltzmann's distribution + + align:start position:0% + + + + align:start position:0% + +so the probability of finding particle + + align:start position:0% +so the probability of finding particle + + + align:start position:0% +so the probability of finding particle +on state I + + align:start position:0% +on state I + + + align:start position:0% +on state I +equals number of particles that say I at + + align:start position:0% +equals number of particles that say I at + + + align:start position:0% +equals number of particles that say I at +that distribution over the total number + + align:start position:0% +that distribution over the total number + + + align:start position:0% +that distribution over the total number +of particles equals e to the minus e i + + align:start position:0% +of particles equals e to the minus e i + + + align:start position:0% +of particles equals e to the minus e i +you're getting sick of seeing me write + + align:start position:0% +you're getting sick of seeing me write + + + align:start position:0% +you're getting sick of seeing me write +this + + align:start position:0% +this + + + align:start position:0% +this +by now + + align:start position:0% +by now + + + align:start position:0% +by now +right prob + + align:start position:0% +right prob + + + align:start position:0% +right prob +of finding + + align:start position:0% + + + + align:start position:0% + +a single particle + + align:start position:0% + + + + align:start position:0% + +in state + + align:start position:0% +in state + + + align:start position:0% +in state +I + + align:start position:0% +I + + + align:start position:0% +I +with energy + + align:start position:0% + + + + align:start position:0% + +e by + + align:start position:0% + + + + align:start position:0% + +okay so um this is a repeat of + + align:start position:0% +okay so um this is a repeat of + + + align:start position:0% +okay so um this is a repeat of +everything we just did I just give it a + + align:start position:0% +everything we just did I just give it a + + + align:start position:0% +everything we just did I just give it a +new name I called it micro canonical so + + align:start position:0% +new name I called it micro canonical so + + + align:start position:0% +new name I called it micro canonical so +again that name's kind of + + align:start position:0% +again that name's kind of + + + align:start position:0% +again that name's kind of +kind of highfalutin but here you have it + + align:start position:0% +kind of highfalutin but here you have it + + + align:start position:0% +kind of highfalutin but here you have it +but + + align:start position:0% + + + + align:start position:0% + +we can generalize + + align:start position:0% +we can generalize + + + align:start position:0% +we can generalize +so now I'm going to tell you about a + + align:start position:0% +so now I'm going to tell you about a + + + align:start position:0% +so now I'm going to tell you about a +different type of Ensemble so we've been + + align:start position:0% +different type of Ensemble so we've been + + + align:start position:0% +different type of Ensemble so we've been +analyzing the micro canonical now I'm + + align:start position:0% +analyzing the micro canonical now I'm + + + align:start position:0% +analyzing the micro canonical now I'm +simply going to tell you about the + + align:start position:0% +simply going to tell you about the + + + align:start position:0% +simply going to tell you about the +existence + + align:start position:0% +existence + + + align:start position:0% +existence +of a canonical ensemble + + align:start position:0% + + + + align:start position:0% + +and please don't ask me where these + + align:start position:0% +and please don't ask me where these + + + align:start position:0% +and please don't ask me where these +names come from + + align:start position:0% +names come from + + + align:start position:0% +names come from +a canonical ensemble + + align:start position:0% +a canonical ensemble + + + align:start position:0% +a canonical ensemble +is the set + + align:start position:0% +is the set + + + align:start position:0% +is the set +of all possible + + align:start position:0% + + + + align:start position:0% + +microstates + + align:start position:0% + + + + align:start position:0% + +of a system + + align:start position:0% + + + + align:start position:0% + +with + + align:start position:0% +with + + + align:start position:0% +with +fixed + + align:start position:0% +fixed + + + align:start position:0% +fixed +volume + + align:start position:0% + + + + align:start position:0% + +and n + + align:start position:0% +and n + + + align:start position:0% +and n +but + + align:start position:0% +but + + + align:start position:0% +but +not + + align:start position:0% +not + + + align:start position:0% +not +energy + + align:start position:0% +energy + + + align:start position:0% +energy +so now we're allowing the system to + + align:start position:0% +so now we're allowing the system to + + + align:start position:0% +so now we're allowing the system to +exchange energy + + align:start position:0% + + + + align:start position:0% + +the system + + align:start position:0% +the system + + + align:start position:0% +the system +is closed + + align:start position:0% + + + + align:start position:0% + +it's rigid + + align:start position:0% +it's rigid + + + align:start position:0% +it's rigid +and closed + + align:start position:0% +and closed + + + align:start position:0% +and closed +so volume and mass are conserved system + + align:start position:0% +so volume and mass are conserved system + + + align:start position:0% +so volume and mass are conserved system +is rigid and closed + + align:start position:0% +is rigid and closed + + + align:start position:0% +is rigid and closed +but can + + align:start position:0% +but can + + + align:start position:0% +but can +Exchange + + align:start position:0% + + + + align:start position:0% + +energy and form + + align:start position:0% +energy and form + + + align:start position:0% +energy and form +of heat + + align:start position:0% + + + + align:start position:0% + +with surroundings + + align:start position:0% + + + + align:start position:0% + +and the system energy + + align:start position:0% + + + + align:start position:0% + +which we're now going to give a label to + + align:start position:0% +which we're now going to give a label to + + + align:start position:0% +which we're now going to give a label to +U sub Nu + + align:start position:0% +U sub Nu + + + align:start position:0% +U sub Nu +the system energy can fluctuate + + align:start position:0% + + + + align:start position:0% + +so I want to draw for you a + + align:start position:0% +so I want to draw for you a + + + align:start position:0% +so I want to draw for you a +representation of the micro of the + + align:start position:0% +representation of the micro of the + + + align:start position:0% +representation of the micro of the +canonical Ensemble so we're going to + + align:start position:0% +canonical Ensemble so we're going to + + + align:start position:0% +canonical Ensemble so we're going to +imagine + + align:start position:0% +imagine + + + align:start position:0% +imagine +um grab a + + align:start position:0% +um grab a + + + align:start position:0% +um grab a +defined tip marker we're going to + + align:start position:0% +defined tip marker we're going to + + + align:start position:0% +defined tip marker we're going to +imagine system + + align:start position:0% + + + + align:start position:0% + +labeled I with energy U + + align:start position:0% +labeled I with energy U + + + align:start position:0% +labeled I with energy U +sub I but this thing is + + align:start position:0% +sub I but this thing is + + + align:start position:0% +sub I but this thing is +um in thermal contact with + + align:start position:0% +um in thermal contact with + + + align:start position:0% +um in thermal contact with +a lot of other systems + + align:start position:0% + + + + align:start position:0% + +so we're going to imagine + + align:start position:0% + + + + align:start position:0% + +a whole + + align:start position:0% +a whole + + + align:start position:0% +a whole +population + + align:start position:0% +population + + + align:start position:0% +population +or if you like an ensemble + + align:start position:0% + + + + align:start position:0% + +of systems + + align:start position:0% +of systems + + + align:start position:0% +of systems +all + + align:start position:0% +all + + + align:start position:0% +all +with fixed volume and fixed particle + + align:start position:0% +with fixed volume and fixed particle + + + align:start position:0% +with fixed volume and fixed particle +number but + + align:start position:0% + + + + align:start position:0% + +with diathermal walls + + align:start position:0% + + + + align:start position:0% + +so if heat is like sound you have to + + align:start position:0% +so if heat is like sound you have to + + + align:start position:0% +so if heat is like sound you have to +imagine this is an apartment building + + align:start position:0% +imagine this is an apartment building + + + align:start position:0% +imagine this is an apartment building +that's really really noisy you hear all + + align:start position:0% +that's really really noisy you hear all + + + align:start position:0% +that's really really noisy you hear all +your neighbors so the volume the volume + + align:start position:0% +your neighbors so the volume the volume + + + align:start position:0% +your neighbors so the volume the volume +mistakes and the particle number is + + align:start position:0% +mistakes and the particle number is + + + align:start position:0% +mistakes and the particle number is +fixed but you're exchanging energy right + + align:start position:0% +fixed but you're exchanging energy right + + + align:start position:0% +fixed but you're exchanging energy right +through the walls + + align:start position:0% +through the walls + + + align:start position:0% +through the walls +but this Ensemble as a whole + + align:start position:0% + + + + align:start position:0% + +so I've drawn an ensemble right I've + + align:start position:0% +so I've drawn an ensemble right I've + + + align:start position:0% +so I've drawn an ensemble right I've +drawn a set or a group considered as a + + align:start position:0% +drawn a set or a group considered as a + + + align:start position:0% +drawn a set or a group considered as a +whole right I've drawn a bunch of + + align:start position:0% +whole right I've drawn a bunch of + + + align:start position:0% +whole right I've drawn a bunch of +subsystems now that can exchange energy + + align:start position:0% +subsystems now that can exchange energy + + + align:start position:0% +subsystems now that can exchange energy +with each other + + align:start position:0% +with each other + + + align:start position:0% +with each other +they each have the same volume well not + + align:start position:0% +they each have the same volume well not + + + align:start position:0% +they each have the same volume well not +as I've drawn it but you can imagine + + align:start position:0% +as I've drawn it but you can imagine + + + align:start position:0% +as I've drawn it but you can imagine +they each have the same volume each have + + align:start position:0% +they each have the same volume each have + + + align:start position:0% +they each have the same volume each have +the same particle number + + align:start position:0% +the same particle number + + + align:start position:0% +the same particle number +but the insoluble as a whole + + align:start position:0% + + + + align:start position:0% + +is isolated + + align:start position:0% + + + + align:start position:0% + +so all these ensembles you have to + + align:start position:0% +so all these ensembles you have to + + + align:start position:0% +so all these ensembles you have to +imagine this being a very very large + + align:start position:0% +imagine this being a very very large + + + align:start position:0% +imagine this being a very very large +number here not just four by six or + + align:start position:0% +number here not just four by six or + + + align:start position:0% +number here not just four by six or +whatever I've drawn + + align:start position:0% +whatever I've drawn + + + align:start position:0% +whatever I've drawn +um + + align:start position:0% +um + + + align:start position:0% +um +is isolated + + align:start position:0% +is isolated + + + align:start position:0% +is isolated +and so this is an ensemble and this is + + align:start position:0% +and so this is an ensemble and this is + + + align:start position:0% +and so this is an ensemble and this is +an ensemble has its own partition + + align:start position:0% +an ensemble has its own partition + + + align:start position:0% +an ensemble has its own partition +function it's known as the canonical + + align:start position:0% + + + + align:start position:0% + +protection function + + align:start position:0% + + + + align:start position:0% + +and that's typically written as Z + + align:start position:0% +and that's typically written as Z + + + align:start position:0% +and that's typically written as Z +and this is now a sum + + align:start position:0% + + + + align:start position:0% + +as before a sum Over States but we're + + align:start position:0% +as before a sum Over States but we're + + + align:start position:0% +as before a sum Over States but we're +not summoning over single particle + + align:start position:0% +not summoning over single particle + + + align:start position:0% +not summoning over single particle +States we're summing over + + align:start position:0% +States we're summing over + + + align:start position:0% +States we're summing over +system energy states + + align:start position:0% + + + + align:start position:0% + +some + + align:start position:0% + + + + align:start position:0% + +over all possible + + align:start position:0% + + + + align:start position:0% + +States + + align:start position:0% + + + + align:start position:0% + +of the system + + align:start position:0% + + + + align:start position:0% + +so it's distinct from before we were + + align:start position:0% +so it's distinct from before we were + + + align:start position:0% +so it's distinct from before we were +summing over single particle States + + align:start position:0% +summing over single particle States + + + align:start position:0% +summing over single particle States +and + + align:start position:0% +and + + + align:start position:0% +and +equilibrium + + align:start position:0% + + + + align:start position:0% + +hold on + + align:start position:0% +hold on + + + align:start position:0% +hold on +when we have equilibrium in an isolated + + align:start position:0% +when we have equilibrium in an isolated + + + align:start position:0% +when we have equilibrium in an isolated +system it was Max entropy + + align:start position:0% +system it was Max entropy + + + align:start position:0% +system it was Max entropy +now I think back two months ago when we + + align:start position:0% +now I think back two months ago when we + + + align:start position:0% +now I think back two months ago when we +had equilibrium for fixed temperature + + align:start position:0% +had equilibrium for fixed temperature + + + align:start position:0% +had equilibrium for fixed temperature +and fixed pressure + + align:start position:0% +and fixed pressure + + + align:start position:0% +and fixed pressure +that was minimum Gibbs + + align:start position:0% + + + + align:start position:0% + +but there was another case which we + + align:start position:0% +but there was another case which we + + + align:start position:0% +but there was another case which we +haven't spent a lot of time on it was + + align:start position:0% +haven't spent a lot of time on it was + + + align:start position:0% +haven't spent a lot of time on it was +equilibrium at fixed volume and fixed + + align:start position:0% +equilibrium at fixed volume and fixed + + + align:start position:0% +equilibrium at fixed volume and fixed +temperature do you remember what + + align:start position:0% +temperature do you remember what + + + align:start position:0% +temperature do you remember what +thermodynamic potential we use when we + + align:start position:0% +thermodynamic potential we use when we + + + align:start position:0% +thermodynamic potential we use when we +have a system at fixed volume and fixed + + align:start position:0% +have a system at fixed volume and fixed + + + align:start position:0% +have a system at fixed volume and fixed +temperature + + align:start position:0% + + + + align:start position:0% + +is it Heim Holtz + + align:start position:0% +is it Heim Holtz + + + align:start position:0% +is it Heim Holtz +equilibrium at minimum + + align:start position:0% +equilibrium at minimum + + + align:start position:0% +equilibrium at minimum +f + + align:start position:0% +f + + + align:start position:0% +f +again we haven't used that this course + + align:start position:0% +again we haven't used that this course + + + align:start position:0% +again we haven't used that this course +basically is minimized + + align:start position:0% + + + + align:start position:0% + +for the distribution + + align:start position:0% + + + + align:start position:0% + +probability of finding system in state + + align:start position:0% +probability of finding system in state + + + align:start position:0% +probability of finding system in state +new + + align:start position:0% +new + + + align:start position:0% +new +equals + + align:start position:0% +equals + + + align:start position:0% +equals +e to the minus U Nu + + align:start position:0% +e to the minus U Nu + + + align:start position:0% +e to the minus U Nu +over KT over Z + + align:start position:0% + + + + align:start position:0% + +so it has the same functional form as + + align:start position:0% +so it has the same functional form as + + + align:start position:0% +so it has the same functional form as +the Bolton distribution + + align:start position:0% +the Bolton distribution + + + align:start position:0% +the Bolton distribution +except + + align:start position:0% +except + + + align:start position:0% +except +instead of single particle energy this + + align:start position:0% +instead of single particle energy this + + + align:start position:0% +instead of single particle energy this +is energy of the system as a whole + + align:start position:0% +is energy of the system as a whole + + + align:start position:0% +is energy of the system as a whole +and instead of maximizing entropy it + + align:start position:0% +and instead of maximizing entropy it + + + align:start position:0% +and instead of maximizing entropy it +minimizes how much free energy + + align:start position:0% +minimizes how much free energy + + + align:start position:0% +minimizes how much free energy +so there's something very similar that's + + align:start position:0% +so there's something very similar that's + + + align:start position:0% +so there's something very similar that's +happening here similar to when we + + align:start position:0% +happening here similar to when we + + + align:start position:0% +happening here similar to when we +started with entropy and then we moved + + align:start position:0% +started with entropy and then we moved + + + align:start position:0% +started with entropy and then we moved +to helmhot's energy and then we move + + align:start position:0% +to helmhot's energy and then we move + + + align:start position:0% +to helmhot's energy and then we move +through Gibbs energy as we change the + + align:start position:0% +through Gibbs energy as we change the + + + align:start position:0% +through Gibbs energy as we change the +boundary conditions of the system and I + + align:start position:0% +boundary conditions of the system and I + + + align:start position:0% +boundary conditions of the system and I +think you'll remember in problem set two + + align:start position:0% +think you'll remember in problem set two + + + align:start position:0% +think you'll remember in problem set two +we really dove into this + + align:start position:0% +we really dove into this + + + align:start position:0% +we really dove into this +so there's something very similar that + + align:start position:0% +so there's something very similar that + + + align:start position:0% +so there's something very similar that +happens in statistical thermodynamics + + align:start position:0% +happens in statistical thermodynamics + + + align:start position:0% +happens in statistical thermodynamics +where you start with the micro canonical + + align:start position:0% +where you start with the micro canonical + + + align:start position:0% +where you start with the micro canonical +Ensemble and its partition function and + + align:start position:0% +Ensemble and its partition function and + + + align:start position:0% +Ensemble and its partition function and +then you go to the canonical Ensemble + + align:start position:0% +then you go to the canonical Ensemble + + + align:start position:0% +then you go to the canonical Ensemble +and its partition function and there's + + align:start position:0% +and its partition function and there's + + + align:start position:0% +and its partition function and there's +more there are other ensembles the next + + align:start position:0% +more there are other ensembles the next + + + align:start position:0% +more there are other ensembles the next +one is called the Grand canonical + + align:start position:0% +one is called the Grand canonical + + + align:start position:0% +one is called the Grand canonical +Ensemble and that corresponds to + + align:start position:0% +Ensemble and that corresponds to + + + align:start position:0% +Ensemble and that corresponds to +situations with fixed pressure and + + align:start position:0% +situations with fixed pressure and + + + align:start position:0% +situations with fixed pressure and +temperature We're Not Gonna + + align:start position:0% +temperature We're Not Gonna + + + align:start position:0% +temperature We're Not Gonna +bother to introduce that + + align:start position:0% +bother to introduce that + + + align:start position:0% +bother to introduce that +so this is the boltzmann distribution + + align:start position:0% + + + + align:start position:0% + +but it's for + + align:start position:0% +but it's for + + + align:start position:0% +but it's for +the canonical ensemble in that + + align:start position:0% + + + + align:start position:0% + +so in this case what was it that you + + align:start position:0% +so in this case what was it that you + + + align:start position:0% +so in this case what was it that you +thought you held constant + + align:start position:0% + + + + align:start position:0% + +um so this is equilibrium at fixed + + align:start position:0% +um so this is equilibrium at fixed + + + align:start position:0% +um so this is equilibrium at fixed +temperature + + align:start position:0% +temperature + + + align:start position:0% +temperature +right when you have when you have + + align:start position:0% +right when you have when you have + + + align:start position:0% +right when you have when you have +um an ensemble of systems + + align:start position:0% +um an ensemble of systems + + + align:start position:0% +um an ensemble of systems +that + + align:start position:0% +that + + + align:start position:0% +that +can't exchange volume + + align:start position:0% +can't exchange volume + + + align:start position:0% +can't exchange volume +and they can't exchange particle number + + align:start position:0% +and they can't exchange particle number + + + align:start position:0% +and they can't exchange particle number +but they can exchange heat energy + + align:start position:0% +but they can exchange heat energy + + + align:start position:0% +but they can exchange heat energy +they reach equilibrium + + align:start position:0% +they reach equilibrium + + + align:start position:0% +they reach equilibrium +when the temperature becomes constant + + align:start position:0% +when the temperature becomes constant + + + align:start position:0% +when the temperature becomes constant +right that's thermal equilibrium + + align:start position:0% +right that's thermal equilibrium + + + align:start position:0% +right that's thermal equilibrium +and so that's what we've done here we've + + align:start position:0% +and so that's what we've done here we've + + + align:start position:0% +and so that's what we've done here we've +set up a system a collection an ensemble + + align:start position:0% +set up a system a collection an ensemble + + + align:start position:0% +set up a system a collection an ensemble +of subsystems that reach thermody + + align:start position:0% +of subsystems that reach thermody + + + align:start position:0% +of subsystems that reach thermody +thermal equilibrium with each other + + align:start position:0% +thermal equilibrium with each other + + + align:start position:0% +thermal equilibrium with each other +because they can exchange heat energy + + align:start position:0% +because they can exchange heat energy + + + align:start position:0% +because they can exchange heat energy +it all works out + + align:start position:0% +it all works out + + + align:start position:0% +it all works out +you end up getting minimum f for this + + align:start position:0% +you end up getting minimum f for this + + + align:start position:0% +you end up getting minimum f for this +distribution + + align:start position:0% +distribution + + + align:start position:0% +distribution +this is the probability + + align:start position:0% +this is the probability + + + align:start position:0% +this is the probability +probability of finding + + align:start position:0% +probability of finding + + + align:start position:0% +probability of finding +system + + align:start position:0% + + + + align:start position:0% + +in state + + align:start position:0% +in state + + + align:start position:0% +in state +new + + align:start position:0% +new + + + align:start position:0% +new +with energy + + align:start position:0% + + + + align:start position:0% + +you + + align:start position:0% +you + + + align:start position:0% +you +have new + + align:start position:0% +have new + + + align:start position:0% +have new +that's what that probability is + + align:start position:0% + + + + align:start position:0% + +okay so I want to leave you with some + + align:start position:0% +okay so I want to leave you with some + + + align:start position:0% +okay so I want to leave you with some +final words on partition functions + + align:start position:0% + + + + align:start position:0% + +we've seen some partition functions + + align:start position:0% +we've seen some partition functions + + + align:start position:0% +we've seen some partition functions +Q + + align:start position:0% +Q + + + align:start position:0% +Q +and z + + align:start position:0% + + + + align:start position:0% + +and and there's there are others which + + align:start position:0% +and and there's there are others which + + + align:start position:0% +and and there's there are others which +we won't cover in this class right + + align:start position:0% +we won't cover in this class right + + + align:start position:0% +we won't cover in this class right +we haven't really covered these and this + + align:start position:0% +we haven't really covered these and this + + + align:start position:0% +we haven't really covered these and this +won't be on the exam I mean there's just + + align:start position:0% +won't be on the exam I mean there's just + + + align:start position:0% +won't be on the exam I mean there's just +sort of commenting on what comes next + + align:start position:0% +sort of commenting on what comes next + + + align:start position:0% +sort of commenting on what comes next +again this is this is in service to + + align:start position:0% +again this is this is in service to + + + align:start position:0% +again this is this is in service to +later classes in our curriculum so the + + align:start position:0% +later classes in our curriculum so the + + + align:start position:0% +later classes in our curriculum so the +partition functions they describe they + + align:start position:0% +partition functions they describe they + + + align:start position:0% +partition functions they describe they +describe + + align:start position:0% +describe + + + align:start position:0% +describe +they describe equilibrium + + align:start position:0% + + + + align:start position:0% + +and + + align:start position:0% +and + + + align:start position:0% +and +fluctuations + + align:start position:0% + + + + align:start position:0% + +the partition functions really describe + + align:start position:0% +the partition functions really describe + + + align:start position:0% +the partition functions really describe +the entire thermodynamic properties of + + align:start position:0% +the entire thermodynamic properties of + + + align:start position:0% +the entire thermodynamic properties of +the system + + align:start position:0% + + + + align:start position:0% + +um + + align:start position:0% +um + + + align:start position:0% +um +so for instance they are the basis + + align:start position:0% + + + + align:start position:0% + +for calculating + + align:start position:0% + + + + align:start position:0% + +thermodynamic properties + + align:start position:0% + + + + align:start position:0% + +and expectation values + + align:start position:0% + + + + align:start position:0% + +that is most likely quantity so for + + align:start position:0% +that is most likely quantity so for + + + align:start position:0% +that is most likely quantity so for +example for example + + align:start position:0% +example for example + + + align:start position:0% +example for example +the mean energy of a system + + align:start position:0% +the mean energy of a system + + + align:start position:0% +the mean energy of a system +can be shown + + align:start position:0% +can be shown + + + align:start position:0% +can be shown +to be this derivative d + + align:start position:0% +to be this derivative d + + + align:start position:0% +to be this derivative d +log Z + + align:start position:0% +log Z + + + align:start position:0% +log Z +1 over KT + + align:start position:0% +1 over KT + + + align:start position:0% +1 over KT +so that's a little bit formal can't + + align:start position:0% +so that's a little bit formal can't + + + align:start position:0% +so that's a little bit formal can't +necessarily calculate anything yet but + + align:start position:0% +necessarily calculate anything yet but + + + align:start position:0% +necessarily calculate anything yet but +in principle if you know the partition + + align:start position:0% +in principle if you know the partition + + + align:start position:0% +in principle if you know the partition +function you can calculate the mean + + align:start position:0% +function you can calculate the mean + + + align:start position:0% +function you can calculate the mean +energy + + align:start position:0% +energy + + + align:start position:0% +energy +the heat capacity of a system + + align:start position:0% +the heat capacity of a system + + + align:start position:0% +the heat capacity of a system +is 1 over KT squared + + align:start position:0% +is 1 over KT squared + + + align:start position:0% +is 1 over KT squared +D Squared log z d + + align:start position:0% +D Squared log z d + + + align:start position:0% +D Squared log z d +1 over k t + + align:start position:0% +1 over k t + + + align:start position:0% +1 over k t +squared + + align:start position:0% + + + + align:start position:0% + +the entropy of a system + + align:start position:0% + + + + align:start position:0% + +can be shown to be mean energy divided + + align:start position:0% +can be shown to be mean energy divided + + + align:start position:0% +can be shown to be mean energy divided +by temperature + + align:start position:0% +by temperature + + + align:start position:0% +by temperature +plus k b + + align:start position:0% +plus k b + + + align:start position:0% +plus k b +log + + align:start position:0% +log + + + align:start position:0% +log +Z + + align:start position:0% +Z + + + align:start position:0% +Z +the helmo three energy of a system + + align:start position:0% +the helmo three energy of a system + + + align:start position:0% +the helmo three energy of a system +is minus k b t log Z + + align:start position:0% +is minus k b t log Z + + + align:start position:0% +is minus k b t log Z +and it's not just equilibrium properties + + align:start position:0% +and it's not just equilibrium properties + + + align:start position:0% +and it's not just equilibrium properties +it's properties of fluctuations + + align:start position:0% +it's properties of fluctuations + + + align:start position:0% +it's properties of fluctuations +so this gets really fun uh in a later + + align:start position:0% +so this gets really fun uh in a later + + + align:start position:0% +so this gets really fun uh in a later +class + + align:start position:0% +class + + + align:start position:0% +class +and has a lot of implications so for + + align:start position:0% +and has a lot of implications so for + + + align:start position:0% +and has a lot of implications so for +example + + align:start position:0% +example + + + align:start position:0% +example +the root mean squared energy fluctuation + + align:start position:0% +the root mean squared energy fluctuation + + + align:start position:0% +the root mean squared energy fluctuation +of a system is another + + align:start position:0% + + + + align:start position:0% + +quantity that can be calculated from the + + align:start position:0% +quantity that can be calculated from the + + + align:start position:0% +quantity that can be calculated from the +partition functions + + align:start position:0% +partition functions + + + align:start position:0% +partition functions +so you know I'm just showing you things + + align:start position:0% +so you know I'm just showing you things + + + align:start position:0% +so you know I'm just showing you things +but you know + + align:start position:0% +but you know + + + align:start position:0% +but you know +if you have the partition function for a + + align:start position:0% +if you have the partition function for a + + + align:start position:0% +if you have the partition function for a +system + + align:start position:0% +system + + + align:start position:0% +system +you can calculate the entire + + align:start position:0% +you can calculate the entire + + + align:start position:0% +you can calculate the entire +thermodynamic properties of that system + + align:start position:0% +thermodynamic properties of that system + + + align:start position:0% +thermodynamic properties of that system +so another example is in in the textbook + + align:start position:0% +so another example is in in the textbook + + + align:start position:0% +so another example is in in the textbook +if you look into Hoff uh they calculate + + align:start position:0% +if you look into Hoff uh they calculate + + + align:start position:0% +if you look into Hoff uh they calculate +the partition function for a couple + + align:start position:0% +the partition function for a couple + + + align:start position:0% +the partition function for a couple +different systems a two level system and + + align:start position:0% +different systems a two level system and + + + align:start position:0% +different systems a two level system and +then a system of um + + align:start position:0% +then a system of um + + + align:start position:0% +then a system of um +a monoatomic gas + + align:start position:0% +a monoatomic gas + + + align:start position:0% +a monoatomic gas +and then by applying formulas such as + + align:start position:0% +and then by applying formulas such as + + + align:start position:0% +and then by applying formulas such as +these they derive the ideal gas law + + align:start position:0% + + + + align:start position:0% + +so it's sort of the ideal gas law from + + align:start position:0% +so it's sort of the ideal gas law from + + + align:start position:0% +so it's sort of the ideal gas law from +first principles right it's no longer + + align:start position:0% +first principles right it's no longer + + + align:start position:0% +first principles right it's no longer +empirical + + align:start position:0% + + + + align:start position:0% + +so I'm going to leave you with some + + align:start position:0% +so I'm going to leave you with some + + + align:start position:0% +so I'm going to leave you with some +thoughts + + align:start position:0% +thoughts + + + align:start position:0% +thoughts +um at this point often students say ah + + align:start position:0% +um at this point often students say ah + + + align:start position:0% +um at this point often students say ah +this is the real stuff this is somehow + + align:start position:0% +this is the real stuff this is somehow + + + align:start position:0% +this is the real stuff this is somehow +the most fundamental + + align:start position:0% +the most fundamental + + + align:start position:0% +the most fundamental +knowledge of thermodynamics is a + + align:start position:0% +knowledge of thermodynamics is a + + + align:start position:0% +knowledge of thermodynamics is a +partition functions + + align:start position:0% +partition functions + + + align:start position:0% +partition functions +right so why did we mess around with all + + align:start position:0% +right so why did we mess around with all + + + align:start position:0% +right so why did we mess around with all +that classical thermodynamics right if + + align:start position:0% +that classical thermodynamics right if + + + align:start position:0% +that classical thermodynamics right if +the partition functions are the keys to + + align:start position:0% +the partition functions are the keys to + + + align:start position:0% +the partition functions are the keys to +the kingdom + + align:start position:0% +the kingdom + + + align:start position:0% +the kingdom +right why not just start there + + align:start position:0% + + + + align:start position:0% + +and the answer is that although this + + align:start position:0% +and the answer is that although this + + + align:start position:0% +and the answer is that although this +this approach is beautiful and elegant + + align:start position:0% +this approach is beautiful and elegant + + + align:start position:0% +this approach is beautiful and elegant +and very powerful in instances it also + + align:start position:0% +and very powerful in instances it also + + + align:start position:0% +and very powerful in instances it also +is extremely limited because we don't + + align:start position:0% +is extremely limited because we don't + + + align:start position:0% +is extremely limited because we don't +know and we can't calculate the + + align:start position:0% +know and we can't calculate the + + + align:start position:0% +know and we can't calculate the +partition functions + + align:start position:0% +partition functions + + + align:start position:0% +partition functions +for all but the most toy problems + + align:start position:0% +for all but the most toy problems + + + align:start position:0% +for all but the most toy problems +and + + align:start position:0% +and + + + align:start position:0% +and +you can see that we if you take + + align:start position:0% +you can see that we if you take + + + align:start position:0% +you can see that we if you take +thermodynamics in a physics department + + align:start position:0% +thermodynamics in a physics department + + + align:start position:0% +thermodynamics in a physics department +you sort of start from this approach you + + align:start position:0% +you sort of start from this approach you + + + align:start position:0% +you sort of start from this approach you +start from the statistical + + align:start position:0% +start from the statistical + + + align:start position:0% +start from the statistical +thermodynamics approach because + + align:start position:0% +thermodynamics approach because + + + align:start position:0% +thermodynamics approach because +um physicists Love Story problems right + + align:start position:0% +um physicists Love Story problems right + + + align:start position:0% +um physicists Love Story problems right +things that's intellectually rich but + + align:start position:0% +things that's intellectually rich but + + + align:start position:0% +things that's intellectually rich but +you know may or may not apply to the + + align:start position:0% +you know may or may not apply to the + + + align:start position:0% +you know may or may not apply to the +real world + + align:start position:0% +real world + + + align:start position:0% +real world +we're a little bit more applied + + align:start position:0% +we're a little bit more applied + + + align:start position:0% +we're a little bit more applied +to give you an example there's a there's + + align:start position:0% +to give you an example there's a there's + + + align:start position:0% +to give you an example there's a there's +a toy model of magnetism known as the + + align:start position:0% +a toy model of magnetism known as the + + + align:start position:0% +a toy model of magnetism known as the +ising model + + align:start position:0% +ising model + + + align:start position:0% +ising model +and the ising model says that you can + + align:start position:0% +and the ising model says that you can + + + align:start position:0% +and the ising model says that you can +have + + align:start position:0% +have + + + align:start position:0% +have +um + + align:start position:0% +um + + + align:start position:0% +um +spins + + align:start position:0% +spins + + + align:start position:0% +spins +on a lattice or magnetic moments I + + align:start position:0% +on a lattice or magnetic moments I + + + align:start position:0% +on a lattice or magnetic moments I +should say on the lattice + + align:start position:0% +should say on the lattice + + + align:start position:0% +should say on the lattice +and they can face up or down that's it + + align:start position:0% +and they can face up or down that's it + + + align:start position:0% +and they can face up or down that's it +so they have a one-dimensional chain and + + align:start position:0% +so they have a one-dimensional chain and + + + align:start position:0% +so they have a one-dimensional chain and +each spin can face up or down and the + + align:start position:0% +each spin can face up or down and the + + + align:start position:0% +each spin can face up or down and the +energy of the system depends on on the + + align:start position:0% +energy of the system depends on on the + + + align:start position:0% +energy of the system depends on on the +orientation of the nearest neighbor it's + + align:start position:0% +orientation of the nearest neighbor it's + + + align:start position:0% +orientation of the nearest neighbor it's +a very simple model of a magnet + + align:start position:0% +a very simple model of a magnet + + + align:start position:0% +a very simple model of a magnet +and so if you if you take a course on + + align:start position:0% +and so if you if you take a course on + + + align:start position:0% +and so if you if you take a course on +magnetism or you take a thermodynamics + + align:start position:0% +magnetism or you take a thermodynamics + + + align:start position:0% +magnetism or you take a thermodynamics +course in the physics department you'll + + align:start position:0% +course in the physics department you'll + + + align:start position:0% +course in the physics department you'll +probably calculate the partition + + align:start position:0% +probably calculate the partition + + + align:start position:0% +probably calculate the partition +function for a 1D eising chain it's not + + align:start position:0% +function for a 1D eising chain it's not + + + align:start position:0% +function for a 1D eising chain it's not +that hard it's kind of fun + + align:start position:0% +that hard it's kind of fun + + + align:start position:0% +that hard it's kind of fun +all right + + align:start position:0% + + + + align:start position:0% + +however if we simply make it a + + align:start position:0% +however if we simply make it a + + + align:start position:0% +however if we simply make it a +two-dimensionalizing system and I'm + + align:start position:0% +two-dimensionalizing system and I'm + + + align:start position:0% +two-dimensionalizing system and I'm +drawing the direction of the arrows at + + align:start position:0% +drawing the direction of the arrows at + + + align:start position:0% +drawing the direction of the arrows at +random here just sort of showing you + + align:start position:0% +random here just sort of showing you + + + align:start position:0% +random here just sort of showing you +right so we just made this from one + + align:start position:0% +right so we just made this from one + + + align:start position:0% +right so we just made this from one +dimensional which is definitely an + + align:start position:0% +dimensional which is definitely an + + + align:start position:0% +dimensional which is definitely an +imaginary thing to a two-dimensional + + align:start position:0% +imaginary thing to a two-dimensional + + + align:start position:0% +imaginary thing to a two-dimensional +which is still imaginary but we're + + align:start position:0% +which is still imaginary but we're + + + align:start position:0% +which is still imaginary but we're +getting there right we're at least + + align:start position:0% +getting there right we're at least + + + align:start position:0% +getting there right we're at least +getting close to real space calculating + + align:start position:0% +getting close to real space calculating + + + align:start position:0% +getting close to real space calculating +a partition function for this model + + align:start position:0% + + + + align:start position:0% + +um is one of the grand intellectual + + align:start position:0% +um is one of the grand intellectual + + + align:start position:0% +um is one of the grand intellectual +achievements of 20th century physics and + + align:start position:0% +achievements of 20th century physics and + + + align:start position:0% +achievements of 20th century physics and +one large answer in Nobel Prize + + align:start position:0% +one large answer in Nobel Prize + + + align:start position:0% +one large answer in Nobel Prize +it's horrendously complicated + + align:start position:0% +it's horrendously complicated + + + align:start position:0% +it's horrendously complicated +mathematically um I've never been able + + align:start position:0% +mathematically um I've never been able + + + align:start position:0% +mathematically um I've never been able +to follow even the first page of that + + align:start position:0% +to follow even the first page of that + + + align:start position:0% +to follow even the first page of that +it's not in any textbooks it's too long + + align:start position:0% + + + + align:start position:0% + +um so let's say I want to model a real + + align:start position:0% +um so let's say I want to model a real + + + align:start position:0% +um so let's say I want to model a real +magnet in three dimensions forget it I + + align:start position:0% +magnet in three dimensions forget it I + + + align:start position:0% +magnet in three dimensions forget it I +mean unless you're kind of Nobel Prize + + align:start position:0% +mean unless you're kind of Nobel Prize + + + align:start position:0% +mean unless you're kind of Nobel Prize +quality um that's that's an open problem + + align:start position:0% +quality um that's that's an open problem + + + align:start position:0% +quality um that's that's an open problem +you have at it but basically the point + + align:start position:0% +you have at it but basically the point + + + align:start position:0% +you have at it but basically the point +is that for real systems that we care + + align:start position:0% +is that for real systems that we care + + + align:start position:0% +is that for real systems that we care +about as Engineers this + + align:start position:0% +about as Engineers this + + + align:start position:0% +about as Engineers this +sort of is a magical construct in theory + + align:start position:0% +sort of is a magical construct in theory + + + align:start position:0% +sort of is a magical construct in theory +this exists + + align:start position:0% +this exists + + + align:start position:0% +this exists +in theory it allows you to calculate all + + align:start position:0% +in theory it allows you to calculate all + + + align:start position:0% +in theory it allows you to calculate all +the properties of the system from first + + align:start position:0% +the properties of the system from first + + + align:start position:0% +the properties of the system from first +principles but in practice it just + + align:start position:0% +principles but in practice it just + + + align:start position:0% +principles but in practice it just +Remains the intellectual exercise + + align:start position:0% +Remains the intellectual exercise + + + align:start position:0% +Remains the intellectual exercise +in practice we have to if you like go + + align:start position:0% +in practice we have to if you like go + + + align:start position:0% +in practice we have to if you like go +with a much more powerful which is the + + align:start position:0% +with a much more powerful which is the + + + align:start position:0% +with a much more powerful which is the +root of classical thermodynamics with + + align:start position:0% +root of classical thermodynamics with + + + align:start position:0% +root of classical thermodynamics with +its postulates and and observations and + + align:start position:0% +its postulates and and observations and + + + align:start position:0% +its postulates and and observations and +data and models \ No newline at end of file diff --git a/Ja9eEQQzTic.txt b/Ja9eEQQzTic.txt new file mode 100644 index 0000000000000000000000000000000000000000..42e57655c262a35dc296428b6a28f2b981af6ebf --- /dev/null +++ b/Ja9eEQQzTic.txt @@ -0,0 +1,7323 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT open courseware continue + + align:start position:0% +will help MIT open courseware continue + + + align:start position:0% +will help MIT open courseware continue +to offer highquality educational + + align:start position:0% +to offer highquality educational + + + align:start position:0% +to offer highquality educational +resources for free to make a donation or + + align:start position:0% +resources for free to make a donation or + + + align:start position:0% +resources for free to make a donation or +to view additional materials from + + align:start position:0% +to view additional materials from + + + align:start position:0% +to view additional materials from +hundreds of MIT courses visit MIT open + + align:start position:0% +hundreds of MIT courses visit MIT open + + + align:start position:0% +hundreds of MIT courses visit MIT open +courseware at + + align:start position:0% + + + + align:start position:0% + +ocw.mit.edu okay all right let's just + + align:start position:0% +ocw.mit.edu okay all right let's just + + + align:start position:0% +ocw.mit.edu okay all right let's just +take got 10 more + + align:start position:0% + + + + align:start position:0% + +seconds all right 92% I like + + align:start position:0% + + + + align:start position:0% + +it that's great I told you there would + + align:start position:0% +it that's great I told you there would + + + align:start position:0% +it that's great I told you there would +be a formal charge question and there + + align:start position:0% +be a formal charge question and there + + + align:start position:0% +be a formal charge question and there +was and you learned it + + align:start position:0% +was and you learned it + + + align:start position:0% +was and you learned it +awesome that's what I like all right so + + align:start position:0% +awesome that's what I like all right so + + + align:start position:0% +awesome that's what I like all right so +that was uh carbon had four no loone + + align:start position:0% +that was uh carbon had four no loone + + + align:start position:0% +that was uh carbon had four no loone +pairs so four minus 0 find minus half of + + align:start position:0% +pairs so four minus 0 find minus half of + + + align:start position:0% +pairs so four minus 0 find minus half of +eight bonding electrons which is four so + + align:start position:0% +eight bonding electrons which is four so + + + align:start position:0% +eight bonding electrons which is four so +four minus 4 is + + align:start position:0% +four minus 4 is + + + align:start position:0% +four minus 4 is +zero okay so today we are having a + + align:start position:0% +zero okay so today we are having a + + + align:start position:0% +zero okay so today we are having a +clicker + + align:start position:0% +clicker + + + align:start position:0% +clicker +competition and problem set four will be + + align:start position:0% +competition and problem set four will be + + + align:start position:0% +competition and problem set four will be +posted later today and today's goal is + + align:start position:0% +posted later today and today's goal is + + + align:start position:0% +posted later today and today's goal is +for all recitations but recitation 12 to + + align:start position:0% +for all recitations but recitation 12 to + + + align:start position:0% +for all recitations but recitation 12 to +try try to uh unseat recitation 12 and + + align:start position:0% +try try to uh unseat recitation 12 and + + + align:start position:0% +try try to uh unseat recitation 12 and +the goal of recitation 12 is of course + + align:start position:0% +the goal of recitation 12 is of course + + + align:start position:0% +the goal of recitation 12 is of course +to win an unprecedented third week in a + + align:start position:0% +to win an unprecedented third week in a + + + align:start position:0% +to win an unprecedented third week in a +row um so that's that's the goal for + + align:start position:0% +row um so that's that's the goal for + + + align:start position:0% +row um so that's that's the goal for +everyone today now remember recitations + + align:start position:0% +everyone today now remember recitations + + + align:start position:0% +everyone today now remember recitations +that win a multiple weeks will be in the + + align:start position:0% +that win a multiple weeks will be in the + + + align:start position:0% +that win a multiple weeks will be in the +playoffs for the clicker competition at + + align:start position:0% +playoffs for the clicker competition at + + + align:start position:0% +playoffs for the clicker competition at +the end of the semester for a specially + + align:start position:0% +the end of the semester for a specially + + + align:start position:0% +the end of the semester for a specially +designed t-shirt + + align:start position:0% + + + + align:start position:0% + +okay more on clicker competitions + + align:start position:0% +okay more on clicker competitions + + + align:start position:0% +okay more on clicker competitions +actually later + + align:start position:0% + + + + align:start position:0% + +today so if we can uh get settled in I + + align:start position:0% +today so if we can uh get settled in I + + + align:start position:0% +today so if we can uh get settled in I +know it's exciting and you are allowed + + align:start position:0% +know it's exciting and you are allowed + + + align:start position:0% +know it's exciting and you are allowed +to talk to your recitations uh other + + align:start position:0% +to talk to your recitations uh other + + + align:start position:0% +to talk to your recitations uh other +recitation members during the clicker + + align:start position:0% +recitation members during the clicker + + + align:start position:0% +recitation members during the clicker +questions that is allowed um but uh + + align:start position:0% +questions that is allowed um but uh + + + align:start position:0% +questions that is allowed um but uh +we'll uh need to cover a little material + + align:start position:0% +we'll uh need to cover a little material + + + align:start position:0% +we'll uh need to cover a little material +first so today we're going to talk about + + align:start position:0% +first so today we're going to talk about + + + align:start position:0% +first so today we're going to talk about +shapes of molecules and I brought uh + + align:start position:0% +shapes of molecules and I brought uh + + + align:start position:0% +shapes of molecules and I brought uh +some molecules with me today to help me + + align:start position:0% +some molecules with me today to help me + + + align:start position:0% +some molecules with me today to help me +out um and we're going to be talking + + align:start position:0% +out um and we're going to be talking + + + align:start position:0% +out um and we're going to be talking +about Vesper Theory + + align:start position:0% +about Vesper Theory + + + align:start position:0% +about Vesper Theory +so why is shapes of molecules + + align:start position:0% +so why is shapes of molecules + + + align:start position:0% +so why is shapes of molecules +important so shape which we can also + + align:start position:0% +important so shape which we can also + + + align:start position:0% +important so shape which we can also +call geometry so you're going to ask + + align:start position:0% +call geometry so you're going to ask + + + align:start position:0% +call geometry so you're going to ask +about the geometry of a molecule you're + + align:start position:0% +about the geometry of a molecule you're + + + align:start position:0% +about the geometry of a molecule you're +asking what is its shape is particularly + + align:start position:0% +asking what is its shape is particularly + + + align:start position:0% +asking what is its shape is particularly +important in chemistry because shape can + + align:start position:0% +important in chemistry because shape can + + + align:start position:0% +important in chemistry because shape can +dictate properties of a particular + + align:start position:0% +dictate properties of a particular + + + align:start position:0% +dictate properties of a particular +molecule it can tell you about or + + align:start position:0% +molecule it can tell you about or + + + align:start position:0% +molecule it can tell you about or +dictate melting points or boiling points + + align:start position:0% +dictate melting points or boiling points + + + align:start position:0% +dictate melting points or boiling points +or + + align:start position:0% +or + + + align:start position:0% +or +reactivity and I'm a biological chemist + + align:start position:0% +reactivity and I'm a biological chemist + + + align:start position:0% +reactivity and I'm a biological chemist +so I care a a lot about shapes of + + align:start position:0% +so I care a a lot about shapes of + + + align:start position:0% +so I care a a lot about shapes of +molecules because in in biology shape is + + align:start position:0% +molecules because in in biology shape is + + + align:start position:0% +molecules because in in biology shape is +really important so you have enzymes in + + align:start position:0% +really important so you have enzymes in + + + align:start position:0% +really important so you have enzymes in +your body catalyzing reactions and for + + align:start position:0% +your body catalyzing reactions and for + + + align:start position:0% +your body catalyzing reactions and for +those enzymes to work they are specially + + align:start position:0% +those enzymes to work they are specially + + + align:start position:0% +those enzymes to work they are specially +designed to react with one particular + + align:start position:0% +designed to react with one particular + + + align:start position:0% +designed to react with one particular +kind of molecule and not any molecule in + + align:start position:0% +kind of molecule and not any molecule in + + + align:start position:0% +kind of molecule and not any molecule in +the cell so they're designed to uh + + align:start position:0% +the cell so they're designed to uh + + + align:start position:0% +the cell so they're designed to uh +recognize the shape of that molecule so + + align:start position:0% +recognize the shape of that molecule so + + + align:start position:0% +recognize the shape of that molecule so +biochemistry really works by shape + + align:start position:0% +biochemistry really works by shape + + + align:start position:0% +biochemistry really works by shape +recognition so shape is very + + align:start position:0% +recognition so shape is very + + + align:start position:0% +recognition so shape is very +important so there's a lot of ways to + + align:start position:0% +important so there's a lot of ways to + + + align:start position:0% +important so there's a lot of ways to +get information about shape + + align:start position:0% +get information about shape + + + align:start position:0% +get information about shape +but there's one very simple theory that + + align:start position:0% +but there's one very simple theory that + + + align:start position:0% +but there's one very simple theory that +does exceedingly well in predicting the + + align:start position:0% +does exceedingly well in predicting the + + + align:start position:0% +does exceedingly well in predicting the +shapes of small molecules and that is + + align:start position:0% +shapes of small molecules and that is + + + align:start position:0% +shapes of small molecules and that is +called the veence shell electron pair + + align:start position:0% +called the veence shell electron pair + + + align:start position:0% +called the veence shell electron pair +repulsion Theory which is known as + + align:start position:0% +repulsion Theory which is known as + + + align:start position:0% +repulsion Theory which is known as +Vesper and is also known as the + + align:start position:0% +Vesper and is also known as the + + + align:start position:0% +Vesper and is also known as the +V Theory I will call it Vesper because + + align:start position:0% +V Theory I will call it Vesper because + + + align:start position:0% +V Theory I will call it Vesper because +it is really hard to say + + align:start position:0% +it is really hard to say + + + align:start position:0% +it is really hard to say +V Theory so Vesper is the topic today + + align:start position:0% +V Theory so Vesper is the topic today + + + align:start position:0% +V Theory so Vesper is the topic today +and this is based on Lewis structures So + + align:start position:0% +and this is based on Lewis structures So + + + align:start position:0% +and this is based on Lewis structures So +This is highly exciting because you just + + align:start position:0% +This is highly exciting because you just + + + align:start position:0% +This is highly exciting because you just +finished a problem set that had you draw + + align:start position:0% +finished a problem set that had you draw + + + align:start position:0% +finished a problem set that had you draw +lots of Lewis structures and now on the + + align:start position:0% +lots of Lewis structures and now on the + + + align:start position:0% +lots of Lewis structures and now on the +next problem set you can draw more Lewis + + align:start position:0% +next problem set you can draw more Lewis + + + align:start position:0% +next problem set you can draw more Lewis +structures and then tell us about his + + align:start position:0% +structures and then tell us about his + + + align:start position:0% +structures and then tell us about his +shape so uh so that's very exciting so + + align:start position:0% +shape so uh so that's very exciting so + + + align:start position:0% +shape so uh so that's very exciting so +you're going to retain all of the + + align:start position:0% +you're going to retain all of the + + + align:start position:0% +you're going to retain all of the +knowledge that you've gained in the last + + align:start position:0% +knowledge that you've gained in the last + + + align:start position:0% +knowledge that you've gained in the last +problem set and continue on with that + + align:start position:0% +problem set and continue on with that + + + align:start position:0% +problem set and continue on with that +problems all right so this is a very + + align:start position:0% +problems all right so this is a very + + + align:start position:0% +problems all right so this is a very +Simple Theory and it's based on the idea + + align:start position:0% +Simple Theory and it's based on the idea + + + align:start position:0% +Simple Theory and it's based on the idea +that valence shell valence electron + + align:start position:0% +that valence shell valence electron + + + align:start position:0% +that valence shell valence electron +pairs repel each + + align:start position:0% +pairs repel each + + + align:start position:0% +pairs repel each +other electrons repel each other they're + + align:start position:0% +other electrons repel each other they're + + + align:start position:0% +other electrons repel each other they're +negatively charged they repel each other + + align:start position:0% +negatively charged they repel each other + + + align:start position:0% +negatively charged they repel each other +that is the heart of this Theory very + + align:start position:0% +that is the heart of this Theory very + + + align:start position:0% +that is the heart of this Theory very +simple and as many of you may have + + align:start position:0% +simple and as many of you may have + + + align:start position:0% +simple and as many of you may have +gathered I love it when very simple + + align:start position:0% +gathered I love it when very simple + + + align:start position:0% +gathered I love it when very simple +theories explain a lot of stuff I enjoy + + align:start position:0% +theories explain a lot of stuff I enjoy + + + align:start position:0% +theories explain a lot of stuff I enjoy +that gets it this doesn't get rate 100% + + align:start position:0% +that gets it this doesn't get rate 100% + + + align:start position:0% +that gets it this doesn't get rate 100% +of the time I'm okay with that I'm good + + align:start position:0% +of the time I'm okay with that I'm good + + + align:start position:0% +of the time I'm okay with that I'm good +with about 90% so this works really + + align:start position:0% +with about 90% so this works really + + + align:start position:0% +with about 90% so this works really +pretty + + align:start position:0% +pretty + + + align:start position:0% +pretty +well so again we're talking about the + + align:start position:0% +well so again we're talking about the + + + align:start position:0% +well so again we're talking about the +geometry around a central atom and the + + align:start position:0% +geometry around a central atom and the + + + align:start position:0% +geometry around a central atom and the +idea is that the atoms are lone pairs + + align:start position:0% +idea is that the atoms are lone pairs + + + align:start position:0% +idea is that the atoms are lone pairs +around that Central atom are going to + + align:start position:0% +around that Central atom are going to + + + align:start position:0% +around that Central atom are going to +move in such a way attain such a shape + + align:start position:0% +move in such a way attain such a shape + + + align:start position:0% +move in such a way attain such a shape +such that the repulsion is minimized so + + align:start position:0% +such that the repulsion is minimized so + + + align:start position:0% +such that the repulsion is minimized so +this is all about minimizing repulsion + + align:start position:0% +this is all about minimizing repulsion + + + align:start position:0% +this is all about minimizing repulsion +minimizing stress again I'm a big fan of + + align:start position:0% +minimizing stress again I'm a big fan of + + + align:start position:0% +minimizing stress again I'm a big fan of +minimizing stress so I also like Vesper + + align:start position:0% +minimizing stress so I also like Vesper + + + align:start position:0% +minimizing stress so I also like Vesper +for that reason as + + align:start position:0% +for that reason as + + + align:start position:0% +for that reason as +well leis + + align:start position:0% +well leis + + + align:start position:0% +well leis +structures what causes stress problem + + align:start position:0% +structures what causes stress problem + + + align:start position:0% +structures what causes stress problem +sets oh but they build + + align:start position:0% + + + + align:start position:0% + +character all + + align:start position:0% +character all + + + align:start position:0% +character all +right + + align:start position:0% +right + + + align:start position:0% +right +Vesper very simple nomenclature again I + + align:start position:0% +Vesper very simple nomenclature again I + + + align:start position:0% +Vesper very simple nomenclature again I +like simple nomenclature a is the + + align:start position:0% +like simple nomenclature a is the + + + align:start position:0% +like simple nomenclature a is the +central atom maybe should be C but Adam + + align:start position:0% +central atom maybe should be C but Adam + + + align:start position:0% +central atom maybe should be C but Adam +is there so so Central atom is a x is + + align:start position:0% +is there so so Central atom is a x is + + + align:start position:0% +is there so so Central atom is a x is +the bonding atom and E is the lone pair + + align:start position:0% +the bonding atom and E is the lone pair + + + align:start position:0% +the bonding atom and E is the lone pair +of electrons so e lone pair electrons X + + align:start position:0% +of electrons so e lone pair electrons X + + + align:start position:0% +of electrons so e lone pair electrons X +is whatever bonding atom and a a is in + + align:start position:0% +is whatever bonding atom and a a is in + + + align:start position:0% +is whatever bonding atom and a a is in +the center a is the central + + align:start position:0% +the center a is the central + + + align:start position:0% +the center a is the central +atom there's one more term you need to + + align:start position:0% +atom there's one more term you need to + + + align:start position:0% +atom there's one more term you need to +know for + + align:start position:0% +know for + + + align:start position:0% +know for +Vesper and that's steric number + + align:start position:0% +Vesper and that's steric number + + + align:start position:0% +Vesper and that's steric number +SN and that's used to predict geometries + + align:start position:0% +SN and that's used to predict geometries + + + align:start position:0% +SN and that's used to predict geometries +so what is steric number + + align:start position:0% +so what is steric number + + + align:start position:0% +so what is steric number +equal steric number is the number of + + align:start position:0% +equal steric number is the number of + + + align:start position:0% +equal steric number is the number of +atoms bonded to the central + + align:start position:0% +atoms bonded to the central + + + align:start position:0% +atoms bonded to the central +atom plus the number of lone pair + + align:start position:0% +atom plus the number of lone pair + + + align:start position:0% +atom plus the number of lone pair +electrons and you count one pair as + + align:start position:0% +electrons and you count one pair as + + + align:start position:0% +electrons and you count one pair as +one and so we want to note when + + align:start position:0% +one and so we want to note when + + + align:start position:0% +one and so we want to note when +considering vasper double triple bonds + + align:start position:0% +considering vasper double triple bonds + + + align:start position:0% +considering vasper double triple bonds +are all and single bonds all the same so + + align:start position:0% +are all and single bonds all the same so + + + align:start position:0% +are all and single bonds all the same so +you don't have to worry about double + + align:start position:0% +you don't have to worry about double + + + align:start position:0% +you don't have to worry about double +triple bonds right now they're all + + align:start position:0% +triple bonds right now they're all + + + align:start position:0% +triple bonds right now they're all +they're all counts the same it's only + + align:start position:0% +they're all counts the same it's only + + + align:start position:0% +they're all counts the same it's only +the number of bonded atoms and the + + align:start position:0% +the number of bonded atoms and the + + + align:start position:0% +the number of bonded atoms and the +number of Lone pairs so let's look at + + align:start position:0% +number of Lone pairs so let's look at + + + align:start position:0% +number of Lone pairs so let's look at +some examples of this so we have our + + align:start position:0% +some examples of this so we have our + + + align:start position:0% +some examples of this so we have our +Central atom a bonded to two bonding + + align:start position:0% +Central atom a bonded to two bonding + + + align:start position:0% +Central atom a bonded to two bonding +atoms x with one lone pair of electrons + + align:start position:0% +atoms x with one lone pair of electrons + + + align:start position:0% +atoms x with one lone pair of electrons +so if you were asked what is the formula + + align:start position:0% +so if you were asked what is the formula + + + align:start position:0% +so if you were asked what is the formula +for this the Vesper formula it would be + + align:start position:0% +for this the Vesper formula it would be + + + align:start position:0% +for this the Vesper formula it would be +a X2 e as shown there and then you might + + align:start position:0% +a X2 e as shown there and then you might + + + align:start position:0% +a X2 e as shown there and then you might +be asked the steric number and the + + align:start position:0% +be asked the steric number and the + + + align:start position:0% +be asked the steric number and the +steric number in this case would be what + + align:start position:0% +steric number in this case would be what + + + align:start position:0% +steric number in this case would be what +three we have two bonding atoms one lone + + align:start position:0% +three we have two bonding atoms one lone + + + align:start position:0% +three we have two bonding atoms one lone +pair of electrons again the lone pair is + + align:start position:0% +pair of electrons again the lone pair is + + + align:start position:0% +pair of electrons again the lone pair is +just counts as + + align:start position:0% +just counts as + + + align:start position:0% +just counts as +one so I could also draw this structure + + align:start position:0% +one so I could also draw this structure + + + align:start position:0% +one so I could also draw this structure +with a double bond to one of the + + align:start position:0% +with a double bond to one of the + + + align:start position:0% +with a double bond to one of the +x's and this would have the equation a + + align:start position:0% +x's and this would have the equation a + + + align:start position:0% +x's and this would have the equation a +x2e exactly the same formula because we + + align:start position:0% +x2e exactly the same formula because we + + + align:start position:0% +x2e exactly the same formula because we +don't care about the double bond in the + + align:start position:0% +don't care about the double bond in the + + + align:start position:0% +don't care about the double bond in the +formula only the number of bonding atoms + + align:start position:0% +formula only the number of bonding atoms + + + align:start position:0% +formula only the number of bonding atoms +only the number of Lone Pairs and this + + align:start position:0% +only the number of Lone Pairs and this + + + align:start position:0% +only the number of Lone Pairs and this +would have an SN number of what three + + align:start position:0% +would have an SN number of what three + + + align:start position:0% +would have an SN number of what three +right because it only matters about the + + align:start position:0% +right because it only matters about the + + + align:start position:0% +right because it only matters about the +lone Pairs and the atoms that's all we + + align:start position:0% +lone Pairs and the atoms that's all we + + + align:start position:0% +lone Pairs and the atoms that's all we +care about here we don't care about the + + align:start position:0% +care about here we don't care about the + + + align:start position:0% +care about here we don't care about the +double bonds triple bonds whatever we'll + + align:start position:0% +double bonds triple bonds whatever we'll + + + align:start position:0% +double bonds triple bonds whatever we'll +care about them later but for right now + + align:start position:0% +care about them later but for right now + + + align:start position:0% +care about them later but for right now +for geometry we're only caring about + + align:start position:0% +for geometry we're only caring about + + + align:start position:0% +for geometry we're only caring about +bonded atoms and lone + + align:start position:0% + + + + align:start position:0% + +pairs some of you will be very happy + + align:start position:0% +pairs some of you will be very happy + + + align:start position:0% +pairs some of you will be very happy +after doing the last problem set to know + + align:start position:0% +after doing the last problem set to know + + + align:start position:0% +after doing the last problem set to know +that you can + + align:start position:0% +that you can + + + align:start position:0% +that you can +apply Vesper Theory to all the resonance + + align:start position:0% +apply Vesper Theory to all the resonance + + + align:start position:0% +apply Vesper Theory to all the resonance +structures that you may come up with + + align:start position:0% +structures that you may come up with + + + align:start position:0% +structures that you may come up with +when you're doing Lew structures so if a + + align:start position:0% +when you're doing Lew structures so if a + + + align:start position:0% +when you're doing Lew structures so if a +molecule has one or more resonance + + align:start position:0% +molecule has one or more resonance + + + align:start position:0% +molecule has one or more resonance +structures that's okay Vesper can be + + align:start position:0% +structures that's okay Vesper can be + + + align:start position:0% +structures that's okay Vesper can be +applied to any one of + + align:start position:0% + + + + align:start position:0% + +them also if there's more than one + + align:start position:0% +them also if there's more than one + + + align:start position:0% +them also if there's more than one +Central atom you need to consider those + + align:start position:0% +Central atom you need to consider those + + + align:start position:0% +Central atom you need to consider those +atoms separately so in this case you + + align:start position:0% +atoms separately so in this case you + + + align:start position:0% +atoms separately so in this case you +would be asked about the geometry around + + align:start position:0% +would be asked about the geometry around + + + align:start position:0% +would be asked about the geometry around +the carbon and the geometry around the + + align:start position:0% +the carbon and the geometry around the + + + align:start position:0% +the carbon and the geometry around the +oxygen + + align:start position:0% +oxygen + + + align:start position:0% +oxygen +but a lot of the examples we have today + + align:start position:0% +but a lot of the examples we have today + + + align:start position:0% +but a lot of the examples we have today +just have one Central atom all right so + + align:start position:0% +just have one Central atom all right so + + + align:start position:0% +just have one Central atom all right so +that's just a little introduction to + + align:start position:0% +that's just a little introduction to + + + align:start position:0% +that's just a little introduction to +Vesper now there are two cases that + + align:start position:0% +Vesper now there are two cases that + + + align:start position:0% +Vesper now there are two cases that +we're going to consider today one are + + align:start position:0% +we're going to consider today one are + + + align:start position:0% +we're going to consider today one are +molecules without loone Pairs and one + + align:start position:0% +molecules without loone Pairs and one + + + align:start position:0% +molecules without loone Pairs and one +are molecules with loone pairs without + + align:start position:0% +are molecules with loone pairs without + + + align:start position:0% +are molecules with loone pairs without +loone pairs is a little bit easier than + + align:start position:0% +loone pairs is a little bit easier than + + + align:start position:0% +loone pairs is a little bit easier than +with loone pairs so let's start + + align:start position:0% +with loone pairs so let's start + + + align:start position:0% +with loone pairs so let's start +there and we have a nice table for you + + align:start position:0% +there and we have a nice table for you + + + align:start position:0% +there and we have a nice table for you +I'll tell you that these lecture notes + + align:start position:0% +I'll tell you that these lecture notes + + + align:start position:0% +I'll tell you that these lecture notes +are of high value I've had people who've + + align:start position:0% +are of high value I've had people who've + + + align:start position:0% +are of high value I've had people who've +taken this course want to come back it's + + align:start position:0% +taken this course want to come back it's + + + align:start position:0% +taken this course want to come back it's +a nice summary of all these shapes so + + align:start position:0% +a nice summary of all these shapes so + + + align:start position:0% +a nice summary of all these shapes so +you want to keep this in a nice secure + + align:start position:0% +you want to keep this in a nice secure + + + align:start position:0% +you want to keep this in a nice secure +location um highly desirable notes okay + + align:start position:0% +location um highly desirable notes okay + + + align:start position:0% +location um highly desirable notes okay +so let's look at a formula type the + + align:start position:0% +so let's look at a formula type the + + + align:start position:0% +so let's look at a formula type the +simplest we have ax2 here so that has an + + align:start position:0% +simplest we have ax2 here so that has an + + + align:start position:0% +simplest we have ax2 here so that has an +SN number of two because it has two + + align:start position:0% +SN number of two because it has two + + + align:start position:0% +SN number of two because it has two +bonded atoms and it has this molecular + + align:start position:0% +bonded atoms and it has this molecular + + + align:start position:0% +bonded atoms and it has this molecular +shape and I brought an example + + align:start position:0% +shape and I brought an example + + + align:start position:0% +shape and I brought an example +here and this is of course a linear + + align:start position:0% +here and this is of course a linear + + + align:start position:0% +here and this is of course a linear +molecule and therefore the angle and + + align:start position:0% +molecule and therefore the angle and + + + align:start position:0% +molecule and therefore the angle and +here we're talking about the angle + + align:start position:0% +here we're talking about the angle + + + align:start position:0% +here we're talking about the angle +around the central atom so from this a + + align:start position:0% +around the central atom so from this a + + + align:start position:0% +around the central atom so from this a +black atom to that black atom we'd have + + align:start position:0% +black atom to that black atom we'd have + + + align:start position:0% +black atom to that black atom we'd have +180 so that's the simplest linear + + align:start position:0% +180 so that's the simplest linear + + + align:start position:0% +180 so that's the simplest linear +molecule so let's get a little more + + align:start position:0% +molecule so let's get a little more + + + align:start position:0% +molecule so let's get a little more +complicated and add three bonding + + align:start position:0% +complicated and add three bonding + + + align:start position:0% +complicated and add three bonding +atoms so here we have a case of a + + align:start position:0% +atoms so here we have a case of a + + + align:start position:0% +atoms so here we have a case of a +X3 it has an SN number of three there're + + align:start position:0% +X3 it has an SN number of three there're + + + align:start position:0% +X3 it has an SN number of three there're +three things bonded to the central atom + + align:start position:0% +three things bonded to the central atom + + + align:start position:0% +three things bonded to the central atom +and it shapes is trigonal planer + + align:start position:0% +and it shapes is trigonal planer + + + align:start position:0% +and it shapes is trigonal planer +trigonal should be remembered it looks + + align:start position:0% +trigonal should be remembered it looks + + + align:start position:0% +trigonal should be remembered it looks +like a triangle and you should also + + align:start position:0% +like a triangle and you should also + + + align:start position:0% +like a triangle and you should also +remember that it's planer you can hold + + align:start position:0% +remember that it's planer you can hold + + + align:start position:0% +remember that it's planer you can hold +it this way and see all of the atoms are + + align:start position:0% +it this way and see all of the atoms are + + + align:start position:0% +it this way and see all of the atoms are +in one plane and I'm making some of this + + align:start position:0% +in one plane and I'm making some of this + + + align:start position:0% +in one plane and I'm making some of this +point because later on the exam when + + align:start position:0% +point because later on the exam when + + + align:start position:0% +point because later on the exam when +you're asked to name geometries of + + align:start position:0% +you're asked to name geometries of + + + align:start position:0% +you're asked to name geometries of +things people come up with all sorts of + + align:start position:0% +things people come up with all sorts of + + + align:start position:0% +things people come up with all sorts of +crazy things so if I spend a little time + + align:start position:0% +crazy things so if I spend a little time + + + align:start position:0% +crazy things so if I spend a little time +doing uh my demonstration here of the + + align:start position:0% +doing uh my demonstration here of the + + + align:start position:0% +doing uh my demonstration here of the +shapes of molecules um it'll pay off + + align:start position:0% +shapes of molecules um it'll pay off + + + align:start position:0% +shapes of molecules um it'll pay off +later in the exam it'll it'll sear in + + align:start position:0% +later in the exam it'll it'll sear in + + + align:start position:0% +later in the exam it'll it'll sear in +your brain it'll be hard to forget + + align:start position:0% +your brain it'll be hard to forget + + + align:start position:0% +your brain it'll be hard to forget +trigonal planer what are the + + align:start position:0% +trigonal planer what are the + + + align:start position:0% +trigonal planer what are the +angles + + align:start position:0% +angles + + + align:start position:0% +angles +120 right okay let's move on we'll have + + align:start position:0% +120 right okay let's move on we'll have + + + align:start position:0% +120 right okay let's move on we'll have +four + + align:start position:0% +four + + + align:start position:0% +four +atoms SN number of four + + align:start position:0% +atoms SN number of four + + + align:start position:0% +atoms SN number of four +ax4 so this is our tetrahedral + + align:start position:0% +ax4 so this is our tetrahedral + + + align:start position:0% +ax4 so this is our tetrahedral +geometry and I'm going to just note as + + align:start position:0% +geometry and I'm going to just note as + + + align:start position:0% +geometry and I'm going to just note as +it says down here that when you have a + + align:start position:0% +it says down here that when you have a + + + align:start position:0% +it says down here that when you have a +thick um Arrow coming out at you + + align:start position:0% +thick um Arrow coming out at you + + + align:start position:0% +thick um Arrow coming out at you +like this Bond and a thin one going back + + align:start position:0% +like this Bond and a thin one going back + + + align:start position:0% +like this Bond and a thin one going back +that means the one coming out is coming + + align:start position:0% +that means the one coming out is coming + + + align:start position:0% +that means the one coming out is coming +straight out toward you the dashed line + + align:start position:0% +straight out toward you the dashed line + + + align:start position:0% +straight out toward you the dashed line +is going back into the screen and the + + align:start position:0% +is going back into the screen and the + + + align:start position:0% +is going back into the screen and the +two that are not um thickened or dashed + + align:start position:0% +two that are not um thickened or dashed + + + align:start position:0% +two that are not um thickened or dashed +are in the plane so if I hold it like + + align:start position:0% +are in the plane so if I hold it like + + + align:start position:0% +are in the plane so if I hold it like +this we have two atoms in the plane one + + align:start position:0% +this we have two atoms in the plane one + + + align:start position:0% +this we have two atoms in the plane one +coming out one going back and so that's + + align:start position:0% +coming out one going back and so that's + + + align:start position:0% +coming out one going back and so that's +the uh that's how if you see that drawn + + align:start position:0% +the uh that's how if you see that drawn + + + align:start position:0% +the uh that's how if you see that drawn +that way and you will um you can think + + align:start position:0% +that way and you will um you can think + + + align:start position:0% +that way and you will um you can think +about it in three dimensions all right + + align:start position:0% +about it in three dimensions all right + + + align:start position:0% +about it in three dimensions all right +so what what's the angle of + + align:start position:0% + + + + align:start position:0% + +tetrahedral + + align:start position:0% + + + + align:start position:0% + +109.5 so a lot of people have already + + align:start position:0% +109.5 so a lot of people have already + + + align:start position:0% +109.5 so a lot of people have already +familiar with this is great if you're + + align:start position:0% +familiar with this is great if you're + + + align:start position:0% +familiar with this is great if you're +not you will learn it quickly when you + + align:start position:0% +not you will learn it quickly when you + + + align:start position:0% +not you will learn it quickly when you +do the problems all right we'll keep + + align:start position:0% +do the problems all right we'll keep + + + align:start position:0% +do the problems all right we'll keep +going we have five I'm going to move + + align:start position:0% +going we have five I'm going to move + + + align:start position:0% +going we have five I'm going to move +over here so SN number of five we have + + align:start position:0% +over here so SN number of five we have + + + align:start position:0% +over here so SN number of five we have +ax5 and here is our shape so this is + + align:start position:0% +ax5 and here is our shape so this is + + + align:start position:0% +ax5 and here is our shape so this is +trigonal by paramal so if you think + + align:start position:0% +trigonal by paramal so if you think + + + align:start position:0% +trigonal by paramal so if you think +about the shape of your trigonal planer + + align:start position:0% +about the shape of your trigonal planer + + + align:start position:0% +about the shape of your trigonal planer +you see along here we have our trigonal + + align:start position:0% +you see along here we have our trigonal + + + align:start position:0% +you see along here we have our trigonal +planer so we have our trigonal shape but + + align:start position:0% +planer so we have our trigonal shape but + + + align:start position:0% +planer so we have our trigonal shape but +we also now have an atom above and an + + align:start position:0% +we also now have an atom above and an + + + align:start position:0% +we also now have an atom above and an +atom below and that forms kind of a a + + align:start position:0% +atom below and that forms kind of a a + + + align:start position:0% +atom below and that forms kind of a a +pyramid on top and pyramid on the bottom + + align:start position:0% +pyramid on top and pyramid on the bottom + + + align:start position:0% +pyramid on top and pyramid on the bottom +so it's trigonal by + + align:start position:0% +so it's trigonal by + + + align:start position:0% +so it's trigonal by +paramal and there are two sets of angles + + align:start position:0% +paramal and there are two sets of angles + + + align:start position:0% +paramal and there are two sets of angles +now what are the angles in the + + align:start position:0% +now what are the angles in the + + + align:start position:0% +now what are the angles in the +equatorial + + align:start position:0% +equatorial + + + align:start position:0% +equatorial +120 I love when people yell things out + + align:start position:0% +120 I love when people yell things out + + + align:start position:0% +120 I love when people yell things out +it's awesome angle from the axial to the + + align:start position:0% +it's awesome angle from the axial to the + + + align:start position:0% +it's awesome angle from the axial to the +equatorial 90 + + align:start position:0% + + + + align:start position:0% + +awesome all right and one more basic + + align:start position:0% +awesome all right and one more basic + + + align:start position:0% +awesome all right and one more basic +shape + + align:start position:0% +shape + + + align:start position:0% +shape +group and that's this one here we have + + align:start position:0% +group and that's this one here we have + + + align:start position:0% +group and that's this one here we have +six atoms bonded to the central atom + + align:start position:0% +six atoms bonded to the central atom + + + align:start position:0% +six atoms bonded to the central atom +ax6 and we have this shape so now I'm + + align:start position:0% +ax6 and we have this shape so now I'm + + + align:start position:0% +ax6 and we have this shape so now I'm +holding it to axial atoms two atoms + + align:start position:0% +holding it to axial atoms two atoms + + + align:start position:0% +holding it to axial atoms two atoms +coming out toward you two going back + + align:start position:0% +coming out toward you two going back + + + align:start position:0% +coming out toward you two going back +octahedral geometry and what are all the + + align:start position:0% +octahedral geometry and what are all the + + + align:start position:0% +octahedral geometry and what are all the +angles here 90 + + align:start position:0% +angles here 90 + + + align:start position:0% +angles here 90 +awesome all + + align:start position:0% + + + + align:start position:0% + +right so let's look at some examples + + align:start position:0% +right so let's look at some examples + + + align:start position:0% +right so let's look at some examples +hopefully everyone got the 90 and can + + align:start position:0% +hopefully everyone got the 90 and can + + + align:start position:0% +hopefully everyone got the 90 and can +write it down if not I'm sure someone + + align:start position:0% +write it down if not I'm sure someone + + + align:start position:0% +write it down if not I'm sure someone +will yell it out again for you all right + + align:start position:0% +will yell it out again for you all right + + + align:start position:0% +will yell it out again for you all right +so let's look at some examples we were + + align:start position:0% +so let's look at some examples we were + + + align:start position:0% +so let's look at some examples we were +talking about CO2 and you calculated the + + align:start position:0% +talking about CO2 and you calculated the + + + align:start position:0% +talking about CO2 and you calculated the +formal charge on it for me um so we have + + align:start position:0% +formal charge on it for me um so we have + + + align:start position:0% +formal charge on it for me um so we have +ax2 SN number of two this is linear and + + align:start position:0% +ax2 SN number of two this is linear and + + + align:start position:0% +ax2 SN number of two this is linear and +and our angle is 180 and now we can + + align:start position:0% +and our angle is 180 and now we can + + + align:start position:0% +and our angle is 180 and now we can +explain why this is non-polar we learned + + align:start position:0% +explain why this is non-polar we learned + + + align:start position:0% +explain why this is non-polar we learned +before that we had polar bonds where we + + align:start position:0% +before that we had polar bonds where we + + + align:start position:0% +before that we had polar bonds where we +had difference of electro negativity + + align:start position:0% +had difference of electro negativity + + + align:start position:0% +had difference of electro negativity +between the carbon and the oxygen which + + align:start position:0% +between the carbon and the oxygen which + + + align:start position:0% +between the carbon and the oxygen which +should make a polar bond so you have two + + align:start position:0% +should make a polar bond so you have two + + + align:start position:0% +should make a polar bond so you have two +polar bonds so why is this not a polar + + align:start position:0% +polar bonds so why is this not a polar + + + align:start position:0% +polar bonds so why is this not a polar +molecule and it's not a polar molecule + + align:start position:0% +molecule and it's not a polar molecule + + + align:start position:0% +molecule and it's not a polar molecule +because this Oxygen's pulling this way + + align:start position:0% +because this Oxygen's pulling this way + + + align:start position:0% +because this Oxygen's pulling this way +this one's pulling that way and that + + align:start position:0% +this one's pulling that way and that + + + align:start position:0% +this one's pulling that way and that +makes it non planer because there's no + + align:start position:0% +makes it non planer because there's no + + + align:start position:0% +makes it non planer because there's no +net dipole so shape is important for + + align:start position:0% +net dipole so shape is important for + + + align:start position:0% +net dipole so shape is important for +this all right let's look at the next + + align:start position:0% +this all right let's look at the next + + + align:start position:0% +this all right let's look at the next +example we've seen a lot of these + + align:start position:0% +example we've seen a lot of these + + + align:start position:0% +example we've seen a lot of these +examples before um we were talking about + + align:start position:0% +examples before um we were talking about + + + align:start position:0% +examples before um we were talking about +Lewis structure what was Boron an + + align:start position:0% +Lewis structure what was Boron an + + + align:start position:0% +Lewis structure what was Boron an +example + + align:start position:0% +example + + + align:start position:0% +example +of INE incomplete OCT that's right so + + align:start position:0% +of INE incomplete OCT that's right so + + + align:start position:0% +of INE incomplete OCT that's right so +here is an example it has three things + + align:start position:0% +here is an example it has three things + + + align:start position:0% +here is an example it has three things +bound bound to it and it has the shape + + align:start position:0% +bound bound to it and it has the shape + + + align:start position:0% +bound bound to it and it has the shape +of trigonal + + align:start position:0% +of trigonal + + + align:start position:0% +of trigonal +planer and the middle atom is incomplete + + align:start position:0% +planer and the middle atom is incomplete + + + align:start position:0% +planer and the middle atom is incomplete +octet but it's okay Boron and which + + align:start position:0% +octet but it's okay Boron and which + + + align:start position:0% +octet but it's okay Boron and which +other one are okay being incomplete + + align:start position:0% +other one are okay being incomplete + + + align:start position:0% +other one are okay being incomplete +octets aluminum + + align:start position:0% +octets aluminum + + + align:start position:0% +octets aluminum +right so the angles are 120 + + align:start position:0% + + + + align:start position:0% + +here now we move on we have this + + align:start position:0% +here now we move on we have this + + + align:start position:0% +here now we move on we have this +molecule CH4 and if someone tell me what + + align:start position:0% +molecule CH4 and if someone tell me what + + + align:start position:0% +molecule CH4 and if someone tell me what +this is + + align:start position:0% +this is + + + align:start position:0% +this is +methane so we have ax4 SN number of four + + align:start position:0% +methane so we have ax4 SN number of four + + + align:start position:0% +methane so we have ax4 SN number of four +and we have our tetrahedral shape and + + align:start position:0% +and we have our tetrahedral shape and + + + align:start position:0% +and we have our tetrahedral shape and +our angles + + align:start position:0% +our angles + + + align:start position:0% +our angles +of + + align:start position:0% +of + + + align:start position:0% +of +109.5 right so methane we should all + + align:start position:0% +109.5 right so methane we should all + + + align:start position:0% +109.5 right so methane we should all +care about greenhouse gas but also some + + align:start position:0% +care about greenhouse gas but also some + + + align:start position:0% +care about greenhouse gas but also some +people believe will be the Salvation to + + align:start position:0% +people believe will be the Salvation to + + + align:start position:0% +people believe will be the Salvation to +our biofuels and energy problem we will + + align:start position:0% +our biofuels and energy problem we will + + + align:start position:0% +our biofuels and energy problem we will +see if that's true or not okay another + + align:start position:0% +see if that's true or not okay another + + + align:start position:0% +see if that's true or not okay another +example over here so we have phosphorus + + align:start position:0% +example over here so we have phosphorus + + + align:start position:0% +example over here so we have phosphorus +in the middle and five chlorines so what + + align:start position:0% +in the middle and five chlorines so what + + + align:start position:0% +in the middle and five chlorines so what +is this an example of in terms of Lewis + + align:start position:0% +is this an example of in terms of Lewis + + + align:start position:0% +is this an example of in terms of Lewis +structures yeah so this is trigonal + + align:start position:0% +structures yeah so this is trigonal + + + align:start position:0% +structures yeah so this is trigonal +b paramal or + + align:start position:0% +b paramal or + + + align:start position:0% +b paramal or +bipyramidal um I think both are right I + + align:start position:0% +bipyramidal um I think both are right I + + + align:start position:0% +bipyramidal um I think both are right I +don't know um and so we have our 120 and + + align:start position:0% +don't know um and so we have our 120 and + + + align:start position:0% +don't know um and so we have our 120 and +R 90 and this was an example we had in + + align:start position:0% +R 90 and this was an example we had in + + + align:start position:0% +R 90 and this was an example we had in +Lewis structures or something very + + align:start position:0% +Lewis structures or something very + + + align:start position:0% +Lewis structures or something very +similar of an expanded octet so we have + + align:start position:0% +similar of an expanded octet so we have + + + align:start position:0% +similar of an expanded octet so we have +more we have five bonds around the + + align:start position:0% +more we have five bonds around the + + + align:start position:0% +more we have five bonds around the +phosphorus and that's okay because it's + + align:start position:0% +phosphorus and that's okay because it's + + + align:start position:0% +phosphorus and that's okay because it's +um n equals 3 or greater so we have + + align:start position:0% +um n equals 3 or greater so we have + + + align:start position:0% +um n equals 3 or greater so we have +example again of an expanded octet and + + align:start position:0% +example again of an expanded octet and + + + align:start position:0% +example again of an expanded octet and +if we keep going we'll have another + + align:start position:0% +if we keep going we'll have another + + + align:start position:0% +if we keep going we'll have another +expanded octet so here we have + + align:start position:0% +expanded octet so here we have + + + align:start position:0% +expanded octet so here we have +ax6 so we have six bonds around the + + align:start position:0% +ax6 so we have six bonds around the + + + align:start position:0% +ax6 so we have six bonds around the +sulfur sulfur is okay with that and what + + align:start position:0% +sulfur sulfur is okay with that and what + + + align:start position:0% +sulfur sulfur is okay with that and what +is the geometry here octahedral + + align:start position:0% +is the geometry here octahedral + + + align:start position:0% +is the geometry here octahedral +angles 90 yep all right so we have + + align:start position:0% +angles 90 yep all right so we have + + + align:start position:0% +angles 90 yep all right so we have +several examples here of things with + + align:start position:0% +several examples here of things with + + + align:start position:0% +several examples here of things with +expanded octets and also um deficient um + + align:start position:0% +expanded octets and also um deficient um + + + align:start position:0% +expanded octets and also um deficient um +uh octets all right so this is pretty + + align:start position:0% +uh octets all right so this is pretty + + + align:start position:0% +uh octets all right so this is pretty +straightforward people get a lot of + + align:start position:0% +straightforward people get a lot of + + + align:start position:0% +straightforward people get a lot of +points on exams except when they come up + + align:start position:0% +points on exams except when they come up + + + align:start position:0% +points on exams except when they come up +with all sorts of weird kind of shapes + + align:start position:0% +with all sorts of weird kind of shapes + + + align:start position:0% +with all sorts of weird kind of shapes +that don't exist but most of the time + + align:start position:0% +that don't exist but most of the time + + + align:start position:0% +that don't exist but most of the time +you can learn this and it's great with + + align:start position:0% +you can learn this and it's great with + + + align:start position:0% +you can learn this and it's great with +with lone pairs is a little more + + align:start position:0% +with lone pairs is a little more + + + align:start position:0% +with lone pairs is a little more +complicated but also much more fun all + + align:start position:0% +complicated but also much more fun all + + + align:start position:0% +complicated but also much more fun all +right so let's talk now about what + + align:start position:0% +right so let's talk now about what + + + align:start position:0% +right so let's talk now about what +happens when we have lone + + align:start position:0% + + + + align:start position:0% + +pairs so electrons in + + align:start position:0% +pairs so electrons in + + + align:start position:0% +pairs so electrons in +bonds are hanging out in their bond and + + align:start position:0% +bonds are hanging out in their bond and + + + align:start position:0% +bonds are hanging out in their bond and +they're not really doing much but being + + align:start position:0% +they're not really doing much but being + + + align:start position:0% +they're not really doing much but being +in their bond so they have less spatial + + align:start position:0% +in their bond so they have less spatial + + + align:start position:0% +in their bond so they have less spatial +distribution than lone pairs meaning + + align:start position:0% +distribution than lone pairs meaning + + + align:start position:0% +distribution than lone pairs meaning +that electrons in bonds take up less + + align:start position:0% +that electrons in bonds take up less + + + align:start position:0% +that electrons in bonds take up less +space and electrons in Lone pairs they + + align:start position:0% +space and electrons in Lone pairs they + + + align:start position:0% +space and electrons in Lone pairs they +can be kind of anywhere they're not + + align:start position:0% +can be kind of anywhere they're not + + + align:start position:0% +can be kind of anywhere they're not +restricted to their bond so they take up + + align:start position:0% +restricted to their bond so they take up + + + align:start position:0% +restricted to their bond so they take up +more space and therefore cause more + + align:start position:0% +more space and therefore cause more + + + align:start position:0% +more space and therefore cause more +repulsion so the whole idea of when + + align:start position:0% +repulsion so the whole idea of when + + + align:start position:0% +repulsion so the whole idea of when +you're talking about Vesper with lone + + align:start position:0% +you're talking about Vesper with lone + + + align:start position:0% +you're talking about Vesper with lone +pairs is you're thinking about electron + + align:start position:0% +pairs is you're thinking about electron + + + align:start position:0% +pairs is you're thinking about electron +pair repulsion and if you have a lone + + align:start position:0% +pair repulsion and if you have a lone + + + align:start position:0% +pair repulsion and if you have a lone +pair that's going to give you more + + align:start position:0% +pair that's going to give you more + + + align:start position:0% +pair that's going to give you more +repulsion than bonded electrons because + + align:start position:0% +repulsion than bonded electrons because + + + align:start position:0% +repulsion than bonded electrons because +lone pair electrons can take up more + + align:start position:0% +lone pair electrons can take up more + + + align:start position:0% +lone pair electrons can take up more +space so it's a very simple idea but it + + align:start position:0% +space so it's a very simple idea but it + + + align:start position:0% +space so it's a very simple idea but it +actually works to explain a lot of stuff + + align:start position:0% +actually works to explain a lot of stuff + + + align:start position:0% +actually works to explain a lot of stuff +and again the geometry rearranges to + + align:start position:0% +and again the geometry rearranges to + + + align:start position:0% +and again the geometry rearranges to +minimize that + + align:start position:0% +minimize that + + + align:start position:0% +minimize that +repulsion so when we're talking about + + align:start position:0% +repulsion so when we're talking about + + + align:start position:0% +repulsion so when we're talking about +repulsive forces then we go from the mo + + align:start position:0% +repulsive forces then we go from the mo + + + align:start position:0% +repulsive forces then we go from the mo +most repulsion lone pair lone + + align:start position:0% +most repulsion lone pair lone + + + align:start position:0% +most repulsion lone pair lone +pair that's like two messy roommates + + align:start position:0% +pair that's like two messy roommates + + + align:start position:0% +pair that's like two messy roommates +living together that's very repulsive + + align:start position:0% +living together that's very repulsive + + + align:start position:0% +living together that's very repulsive +situation lone pair bonding pair and + + align:start position:0% +situation lone pair bonding pair and + + + align:start position:0% +situation lone pair bonding pair and +then bonding pair bonding pair is the + + align:start position:0% +then bonding pair bonding pair is the + + + align:start position:0% +then bonding pair bonding pair is the +least repulsive to neat roommates that + + align:start position:0% +least repulsive to neat roommates that + + + align:start position:0% +least repulsive to neat roommates that +usually works out quite well so if we + + align:start position:0% +usually works out quite well so if we + + + align:start position:0% +usually works out quite well so if we +keep this in mind we can now predict + + align:start position:0% +keep this in mind we can now predict + + + align:start position:0% +keep this in mind we can now predict +shapes of molecules based on this + + align:start position:0% +shapes of molecules based on this + + + align:start position:0% +shapes of molecules based on this +repulsion so we can rationalize shapes + + align:start position:0% +repulsion so we can rationalize shapes + + + align:start position:0% +repulsion so we can rationalize shapes +based on Vesper + + align:start position:0% + + + + align:start position:0% + +Theory so now we can think about + + align:start position:0% +Theory so now we can think about + + + align:start position:0% +Theory so now we can think about +ax4e has a seesaw shape which of these + + align:start position:0% +ax4e has a seesaw shape which of these + + + align:start position:0% +ax4e has a seesaw shape which of these +two shapes is seesaw so we have one + + align:start position:0% +two shapes is seesaw so we have one + + + align:start position:0% +two shapes is seesaw so we have one +case I'll make this one where we have + + align:start position:0% +case I'll make this one where we have + + + align:start position:0% +case I'll make this one where we have +the lone pair in an axial position and + + align:start position:0% +the lone pair in an axial position and + + + align:start position:0% +the lone pair in an axial position and +we have another case where we have the + + align:start position:0% +we have another case where we have the + + + align:start position:0% +we have another case where we have the +lone pair in an equatorial + + align:start position:0% +lone pair in an equatorial + + + align:start position:0% +lone pair in an equatorial +position so when you have + + align:start position:0% +position so when you have + + + align:start position:0% +position so when you have +it in the axial position here + + align:start position:0% +it in the axial position here + + + align:start position:0% +it in the axial position here +here you have three bonding pairs of + + align:start position:0% +here you have three bonding pairs of + + + align:start position:0% +here you have three bonding pairs of +bonding electrons pretty close they're + + align:start position:0% +bonding electrons pretty close they're + + + align:start position:0% +bonding electrons pretty close they're +90° away from each other so there are + + align:start position:0% +90° away from each other so there are + + + align:start position:0% +90° away from each other so there are +three sets of bonding electrons that + + align:start position:0% +three sets of bonding electrons that + + + align:start position:0% +three sets of bonding electrons that +will be repelled pretty + + align:start position:0% +will be repelled pretty + + + align:start position:0% +will be repelled pretty +strongly now clicker question think + + align:start position:0% +strongly now clicker question think + + + align:start position:0% +strongly now clicker question think +about what's going to be true here how + + align:start position:0% +about what's going to be true here how + + + align:start position:0% +about what's going to be true here how +many things with an equatorial loone + + align:start position:0% +many things with an equatorial loone + + + align:start position:0% +many things with an equatorial loone +pair will be repelled strongly + + align:start position:0% + + + + align:start position:0% + +very repulsive those lone + + align:start position:0% + + + + align:start position:0% + +pairs okay so that was the answer we're + + align:start position:0% +pairs okay so that was the answer we're + + + align:start position:0% +pairs okay so that was the answer we're +going for two because there are two sets + + align:start position:0% +going for two because there are two sets + + + align:start position:0% +going for two because there are two sets +of bonding electrons here that are 90 + + align:start position:0% +of bonding electrons here that are 90 + + + align:start position:0% +of bonding electrons here that are 90 +Dees away there're two that are 120 but + + align:start position:0% +Dees away there're two that are 120 but + + + align:start position:0% +Dees away there're two that are 120 but +120 is bigger than 90 so they're two + + align:start position:0% +120 is bigger than 90 so they're two + + + align:start position:0% +120 is bigger than 90 so they're two +that are close whereas with this + + align:start position:0% +that are close whereas with this + + + align:start position:0% +that are close whereas with this +geometry they're three um sets of + + align:start position:0% +geometry they're three um sets of + + + align:start position:0% +geometry they're three um sets of +bonding electrons that are 90 degrees + + align:start position:0% +bonding electrons that are 90 degrees + + + align:start position:0% +bonding electrons that are 90 degrees +away so it turns out that the equatorial + + align:start position:0% +away so it turns out that the equatorial + + + align:start position:0% +away so it turns out that the equatorial +lone pair is more favorable it has a + + align:start position:0% +lone pair is more favorable it has a + + + align:start position:0% +lone pair is more favorable it has a +little bit more room in the equatorial + + align:start position:0% +little bit more room in the equatorial + + + align:start position:0% +little bit more room in the equatorial +area to spread out and so this is the + + align:start position:0% +area to spread out and so this is the + + + align:start position:0% +area to spread out and so this is the +shape that we find we never see this + + align:start position:0% +shape that we find we never see this + + + align:start position:0% +shape that we find we never see this +shape does not exist we'll just take + + align:start position:0% +shape does not exist we'll just take + + + align:start position:0% +shape does not exist we'll just take +that away it doesn't exist and this is + + align:start position:0% +that away it doesn't exist and this is + + + align:start position:0% +that away it doesn't exist and this is +called + + align:start position:0% +called + + + align:start position:0% +called +seesaw and let me demonstrate to you why + + align:start position:0% +seesaw and let me demonstrate to you why + + + align:start position:0% +seesaw and let me demonstrate to you why +that is the + + align:start position:0% + + + + align:start position:0% + +case maybe I'll do it this + + align:start position:0% + + + + align:start position:0% + +way so how many of you had seesaws in a + + align:start position:0% +way so how many of you had seesaws in a + + + align:start position:0% +way so how many of you had seesaws in a +playground quite a number seesaws are + + align:start position:0% +playground quite a number seesaws are + + + align:start position:0% +playground quite a number seesaws are +not considered that safe you know the + + align:start position:0% +not considered that safe you know the + + + align:start position:0% +not considered that safe you know the +heavy kid sits on it keep keeps you up + + align:start position:0% +heavy kid sits on it keep keeps you up + + + align:start position:0% +heavy kid sits on it keep keeps you up +in the air for days or whatever until + + align:start position:0% +in the air for days or whatever until + + + align:start position:0% +in the air for days or whatever until +your mom comes and gets you from the + + align:start position:0% +your mom comes and gets you from the + + + align:start position:0% +your mom comes and gets you from the +playground or gets off suddenly and the + + align:start position:0% +playground or gets off suddenly and the + + + align:start position:0% +playground or gets off suddenly and the +Seesaw flips and you go flying in the + + align:start position:0% +Seesaw flips and you go flying in the + + + align:start position:0% +Seesaw flips and you go flying in the +air um but studies show actually that + + align:start position:0% +air um but studies show actually that + + + align:start position:0% +air um but studies show actually that +dangerous playground equipment builds uh + + align:start position:0% +dangerous playground equipment builds uh + + + align:start position:0% +dangerous playground equipment builds uh +neural networks and is good for uh + + align:start position:0% +neural networks and is good for uh + + + align:start position:0% +neural networks and is good for uh +cognitive development so um I think we + + align:start position:0% +cognitive development so um I think we + + + align:start position:0% +cognitive development so um I think we +could do a survey here and see if + + align:start position:0% +could do a survey here and see if + + + align:start position:0% +could do a survey here and see if +there's a correlation between how many + + align:start position:0% +there's a correlation between how many + + + align:start position:0% +there's a correlation between how many +of you played with seesaws when you were + + align:start position:0% +of you played with seesaws when you were + + + align:start position:0% +of you played with seesaws when you were +a kid and whether you ended up as an MIT + + align:start position:0% +a kid and whether you ended up as an MIT + + + align:start position:0% +a kid and whether you ended up as an MIT +student or not that could be that could + + align:start position:0% +student or not that could be that could + + + align:start position:0% +student or not that could be that could +be interesting but now none of you will + + align:start position:0% +be interesting but now none of you will + + + align:start position:0% +be interesting but now none of you will +ever forget that this shape is seesaw + + align:start position:0% +ever forget that this shape is seesaw + + + align:start position:0% +ever forget that this shape is seesaw +right you'll remember this forever + + align:start position:0% +right you'll remember this forever + + + align:start position:0% +right you'll remember this forever +okay all right + + align:start position:0% +okay all right + + + align:start position:0% +okay all right +so this idea also is + + align:start position:0% +so this idea also is + + + align:start position:0% +so this idea also is +responsible um for a t-shaped + + align:start position:0% +responsible um for a t-shaped + + + align:start position:0% +responsible um for a t-shaped +molecule so we'll add another one and I + + align:start position:0% +molecule so we'll add another one and I + + + align:start position:0% +molecule so we'll add another one and I +think this is a little harder to + + align:start position:0% +think this is a little harder to + + + align:start position:0% +think this is a little harder to +rationalize why it wouldn't go in a + + align:start position:0% +rationalize why it wouldn't go in a + + + align:start position:0% +rationalize why it wouldn't go in a +different place but it does this is how + + align:start position:0% +different place but it does this is how + + + align:start position:0% +different place but it does this is how +it goes both the lone pairs are in + + align:start position:0% +it goes both the lone pairs are in + + + align:start position:0% +it goes both the lone pairs are in +equatorial positions and we get + + align:start position:0% +equatorial positions and we get + + + align:start position:0% +equatorial positions and we get +something that looks like a t so if you + + align:start position:0% +something that looks like a t so if you + + + align:start position:0% +something that looks like a t so if you +have a + + align:start position:0% +have a + + + align:start position:0% +have a +X3 or ax3 E2 sn5 number it's a t-shaped + + align:start position:0% +X3 or ax3 E2 sn5 number it's a t-shaped + + + align:start position:0% +X3 or ax3 E2 sn5 number it's a t-shaped +molecule we can also think about our + + align:start position:0% +molecule we can also think about our + + + align:start position:0% +molecule we can also think about our +core octahedral + + align:start position:0% +core octahedral + + + align:start position:0% +core octahedral +geometry and if you have two lone pairs + + align:start position:0% +geometry and if you have two lone pairs + + + align:start position:0% +geometry and if you have two lone pairs +so here's our octahedral with six + + align:start position:0% +so here's our octahedral with six + + + align:start position:0% +so here's our octahedral with six +bonding atoms and if you have two lone + + align:start position:0% +bonding atoms and if you have two lone + + + align:start position:0% +bonding atoms and if you have two lone +Pairs and four bonding atoms if you have + + align:start position:0% +Pairs and four bonding atoms if you have + + + align:start position:0% +Pairs and four bonding atoms if you have +ax4 E2 it has this shape the lone pairs + + align:start position:0% +ax4 E2 it has this shape the lone pairs + + + align:start position:0% +ax4 E2 it has this shape the lone pairs +go on opposite sides and now they have + + align:start position:0% +go on opposite sides and now they have + + + align:start position:0% +go on opposite sides and now they have +they're repelling the bonding electrons + + align:start position:0% +they're repelling the bonding electrons + + + align:start position:0% +they're repelling the bonding electrons +here but they're far away from each + + align:start position:0% +here but they're far away from each + + + align:start position:0% +here but they're far away from each +other which is favorable and this is + + align:start position:0% +other which is favorable and this is + + + align:start position:0% +other which is favorable and this is +called Square planer so it's square and + + align:start position:0% +called Square planer so it's square and + + + align:start position:0% +called Square planer so it's square and +it's + + align:start position:0% +it's + + + align:start position:0% +it's +planer Square planer okay the two lone + + align:start position:0% +planer Square planer okay the two lone + + + align:start position:0% +planer Square planer okay the two lone +pairs are far apart on the opposite + + align:start position:0% +pairs are far apart on the opposite + + + align:start position:0% +pairs are far apart on the opposite +sides of the + + align:start position:0% +sides of the + + + align:start position:0% +sides of the +bond so in addition to predicting these + + align:start position:0% +bond so in addition to predicting these + + + align:start position:0% +bond so in addition to predicting these +shapes which work pretty well we can + + align:start position:0% +shapes which work pretty well we can + + + align:start position:0% +shapes which work pretty well we can +also think about the geometries and when + + align:start position:0% +also think about the geometries and when + + + align:start position:0% +also think about the geometries and when +you get lone pairs you find deviations + + align:start position:0% +you get lone pairs you find deviations + + + align:start position:0% +you get lone pairs you find deviations +from your standard geometries so let's + + align:start position:0% +from your standard geometries so let's + + + align:start position:0% +from your standard geometries so let's +look at some examples so with molecules + + align:start position:0% +look at some examples so with molecules + + + align:start position:0% +look at some examples so with molecules +with lone pairs such as + + align:start position:0% +with lone pairs such as + + + align:start position:0% +with lone pairs such as +NH3 the angles tend to be + + align:start position:0% +NH3 the angles tend to be + + + align:start position:0% +NH3 the angles tend to be +smaller so we saw methane before it was + + align:start position:0% +smaller so we saw methane before it was + + + align:start position:0% +smaller so we saw methane before it was +109.5 you yelled that nicely out for + + align:start position:0% +109.5 you yelled that nicely out for + + + align:start position:0% +109.5 you yelled that nicely out for +me these are both sn4 + + align:start position:0% +me these are both sn4 + + + align:start position:0% +me these are both sn4 +this is ax4 this is ax uh 3 e but it's + + align:start position:0% +this is ax4 this is ax uh 3 e but it's + + + align:start position:0% +this is ax4 this is ax uh 3 e but it's +still an sn4 system so it looks like + + align:start position:0% +still an sn4 system so it looks like + + + align:start position:0% +still an sn4 system so it looks like +this we have here we have methane here + + align:start position:0% +this we have here we have methane here + + + align:start position:0% +this we have here we have methane here +we have NH3 and now we want to think + + align:start position:0% +we have NH3 and now we want to think + + + align:start position:0% +we have NH3 and now we want to think +about which would be more repulsive the + + align:start position:0% +about which would be more repulsive the + + + align:start position:0% +about which would be more repulsive the +bonded electrons or the lone pair + + align:start position:0% +bonded electrons or the lone pair + + + align:start position:0% +bonded electrons or the lone pair +electrons in terms of the geometries + + align:start position:0% +electrons in terms of the geometries + + + align:start position:0% +electrons in terms of the geometries +around so if we have hydrogen carbon + + align:start position:0% +around so if we have hydrogen carbon + + + align:start position:0% +around so if we have hydrogen carbon +hydrogen angle of 109.5 here then here + + align:start position:0% +hydrogen angle of 109.5 here then here + + + align:start position:0% +hydrogen angle of 109.5 here then here +with nitrogen we're thinking about + + align:start position:0% +with nitrogen we're thinking about + + + align:start position:0% +with nitrogen we're thinking about +hydrogen nitrogen hydrogen and this lone + + align:start position:0% +hydrogen nitrogen hydrogen and this lone + + + align:start position:0% +hydrogen nitrogen hydrogen and this lone +pair is pushing on those um bonded + + align:start position:0% +pair is pushing on those um bonded + + + align:start position:0% +pair is pushing on those um bonded +electrons and it's taken up a lot of + + align:start position:0% +electrons and it's taken up a lot of + + + align:start position:0% +electrons and it's taken up a lot of +space this is the messy roommate the + + align:start position:0% +space this is the messy roommate the + + + align:start position:0% +space this is the messy roommate the +messy roommate it has a lot of stuff + + align:start position:0% +messy roommate it has a lot of stuff + + + align:start position:0% +messy roommate it has a lot of stuff +that's spreading out all over your room + + align:start position:0% +that's spreading out all over your room + + + align:start position:0% +that's spreading out all over your room +and so instead of having 109.5 amount of + + align:start position:0% +and so instead of having 109.5 amount of + + + align:start position:0% +and so instead of having 109.5 amount of +space you now have + + align:start position:0% +space you now have + + + align:start position:0% +space you now have +106.7 amount of space in your room + + align:start position:0% +106.7 amount of space in your room + + + align:start position:0% +106.7 amount of space in your room +because it's just the messy roommates + + align:start position:0% +because it's just the messy roommates + + + align:start position:0% +because it's just the messy roommates +just spreading out all over price + + align:start position:0% +just spreading out all over price + + + align:start position:0% +just spreading out all over price +pushing down on those bonds and the + + align:start position:0% +pushing down on those bonds and the + + + align:start position:0% +pushing down on those bonds and the +bonds + + align:start position:0% +bonds + + + align:start position:0% +bonds +contract all right now let's go back to + + align:start position:0% +contract all right now let's go back to + + + align:start position:0% +contract all right now let's go back to +Trends in the periodic table for a + + align:start position:0% +Trends in the periodic table for a + + + align:start position:0% +Trends in the periodic table for a +minute we learned that atomic size + + align:start position:0% +minute we learned that atomic size + + + align:start position:0% +minute we learned that atomic size +increases as we go down the periodic + + align:start position:0% +increases as we go down the periodic + + + align:start position:0% +increases as we go down the periodic +table because what + + align:start position:0% +table because what + + + align:start position:0% +table because what +increases n principal quantum number n + + align:start position:0% +increases n principal quantum number n + + + align:start position:0% +increases n principal quantum number n +increases so atomic size increases as we + + align:start position:0% +increases so atomic size increases as we + + + align:start position:0% +increases so atomic size increases as we +go down think of this as a messy + + align:start position:0% +go down think of this as a messy + + + align:start position:0% +go down think of this as a messy +roommate having more + + align:start position:0% +roommate having more + + + align:start position:0% +roommate having more +stuff so the lone pairs now occupy a + + align:start position:0% +stuff so the lone pairs now occupy a + + + align:start position:0% +stuff so the lone pairs now occupy a +larger volume still messy but now messy + + align:start position:0% +larger volume still messy but now messy + + + align:start position:0% +larger volume still messy but now messy +with a lot more stuff and this stuff + + align:start position:0% +with a lot more stuff and this stuff + + + align:start position:0% +with a lot more stuff and this stuff +impedes in your + + align:start position:0% +impedes in your + + + align:start position:0% +impedes in your +space so the angles tend to be even + + align:start position:0% +space so the angles tend to be even + + + align:start position:0% +space so the angles tend to be even +smaller between the bonded atoms so we + + align:start position:0% +smaller between the bonded atoms so we + + + align:start position:0% +smaller between the bonded atoms so we +had NH3 before at 106 + + align:start position:0% +had NH3 before at 106 + + + align:start position:0% +had NH3 before at 106 +7 but nitrogen is up here phosphorus is + + align:start position:0% +7 but nitrogen is up here phosphorus is + + + align:start position:0% +7 but nitrogen is up here phosphorus is +below it so it has a bigger atomic size + + align:start position:0% +below it so it has a bigger atomic size + + + align:start position:0% +below it so it has a bigger atomic size +and it has lone pairs that occupy larger + + align:start position:0% +and it has lone pairs that occupy larger + + + align:start position:0% +and it has lone pairs that occupy larger +volumes so this is what + + align:start position:0% + + + + align:start position:0% + +happens some of you may have experienced + + align:start position:0% +happens some of you may have experienced + + + align:start position:0% +happens some of you may have experienced +that that is a messy roommate with a lot + + align:start position:0% +that that is a messy roommate with a lot + + + align:start position:0% +that that is a messy roommate with a lot +of stuff now if you have a roommate + + align:start position:0% +of stuff now if you have a roommate + + + align:start position:0% +of stuff now if you have a roommate +that's very neat they're putting their + + align:start position:0% +that's very neat they're putting their + + + align:start position:0% +that's very neat they're putting their +clothes in drawers when the clothes are + + align:start position:0% +clothes in drawers when the clothes are + + + align:start position:0% +clothes in drawers when the clothes are +in drawers just like electon and bonds + + align:start position:0% +in drawers just like electon and bonds + + + align:start position:0% +in drawers just like electon and bonds +they don't really go any place but when + + align:start position:0% +they don't really go any place but when + + + align:start position:0% +they don't really go any place but when +the messy roommate does not put their + + align:start position:0% +the messy roommate does not put their + + + align:start position:0% +the messy roommate does not put their +clothes when their lone pair clothes + + align:start position:0% +clothes when their lone pair clothes + + + align:start position:0% +clothes when their lone pair clothes +then they go and this is what + + align:start position:0% +then they go and this is what + + + align:start position:0% +then they go and this is what +happens okay so we can predict Now by + + align:start position:0% +happens okay so we can predict Now by + + + align:start position:0% +happens okay so we can predict Now by +looking at periodic trends and thinking + + align:start position:0% +looking at periodic trends and thinking + + + align:start position:0% +looking at periodic trends and thinking +about how much room those lone pair + + align:start position:0% +about how much room those lone pair + + + align:start position:0% +about how much room those lone pair +electrons are taking up we can think + + align:start position:0% +electrons are taking up we can think + + + align:start position:0% +electrons are taking up we can think +about and predict the angle between the + + align:start position:0% +about and predict the angle between the + + + align:start position:0% +about and predict the angle between the +bonded + + align:start position:0% +bonded + + + align:start position:0% +bonded +atoms all right so this is pretty cool + + align:start position:0% +atoms all right so this is pretty cool + + + align:start position:0% +atoms all right so this is pretty cool +but can it save the + + align:start position:0% + + + + align:start position:0% + +world what do you think can veser save + + align:start position:0% +world what do you think can veser save + + + align:start position:0% +world what do you think can veser save +the + + align:start position:0% +the + + + align:start position:0% +the +world do something important of course + + align:start position:0% +world do something important of course + + + align:start position:0% +world do something important of course +it can it's part of + + align:start position:0% +it can it's part of + + + align:start position:0% +it can it's part of +chemistr so let's think about a pressing + + align:start position:0% +chemistr so let's think about a pressing + + + align:start position:0% +chemistr so let's think about a pressing +problem in the world right now and how + + align:start position:0% +problem in the world right now and how + + + align:start position:0% +problem in the world right now and how +Vesper can address it and if you listen + + align:start position:0% +Vesper can address it and if you listen + + + align:start position:0% +Vesper can address it and if you listen +to NPR or open a newspaper these days + + align:start position:0% +to NPR or open a newspaper these days + + + align:start position:0% +to NPR or open a newspaper these days +you're hearing about a lot of car bomb + + align:start position:0% +you're hearing about a lot of car bomb + + + align:start position:0% +you're hearing about a lot of car bomb +explosions things are not good in the + + align:start position:0% +explosions things are not good in the + + + align:start position:0% +explosions things are not good in the +Middle East um we're hearing about all + + align:start position:0% +Middle East um we're hearing about all + + + align:start position:0% +Middle East um we're hearing about all +sorts I heard on the news about bombs + + align:start position:0% +sorts I heard on the news about bombs + + + align:start position:0% +sorts I heard on the news about bombs +going off at a school and then when + + align:start position:0% +going off at a school and then when + + + align:start position:0% +going off at a school and then when +parents rushed toward the school more + + align:start position:0% +parents rushed toward the school more + + + align:start position:0% +parents rushed toward the school more +bombs went off I mean just really + + align:start position:0% +bombs went off I mean just really + + + align:start position:0% +bombs went off I mean just really +horrible stories um and even when the + + align:start position:0% +horrible stories um and even when the + + + align:start position:0% +horrible stories um and even when the +conflict is over a lot of times those + + align:start position:0% +conflict is over a lot of times those + + + align:start position:0% +conflict is over a lot of times those +improvised explosives are still there + + align:start position:0% +improvised explosives are still there + + + align:start position:0% +improvised explosives are still there +they still exist in the countries and + + align:start position:0% +they still exist in the countries and + + + align:start position:0% +they still exist in the countries and +it's estimated by the UN by the United + + align:start position:0% +it's estimated by the UN by the United + + + align:start position:0% +it's estimated by the UN by the United +Nations that land kill 15,000 to 20,000 + + align:start position:0% +Nations that land kill 15,000 to 20,000 + + + align:start position:0% +Nations that land kill 15,000 to 20,000 +people mostly children uh women elderly + + align:start position:0% +people mostly children uh women elderly + + + align:start position:0% +people mostly children uh women elderly +who are out in the farm Fields trying to + + align:start position:0% +who are out in the farm Fields trying to + + + align:start position:0% +who are out in the farm Fields trying to +uh grow food for their family and they + + align:start position:0% +uh grow food for their family and they + + + align:start position:0% +uh grow food for their family and they +step on something and blow up so how do + + align:start position:0% +step on something and blow up so how do + + + align:start position:0% +step on something and blow up so how do +you find these explosive devices how do + + align:start position:0% +you find these explosive devices how do + + + align:start position:0% +you find these explosive devices how do +you find explosive devices that are + + align:start position:0% +you find explosive devices that are + + + align:start position:0% +you find explosive devices that are +actively being used now in dangerous + + align:start position:0% +actively being used now in dangerous + + + align:start position:0% +actively being used now in dangerous +parts of the world and how do you find + + align:start position:0% +parts of the world and how do you find + + + align:start position:0% +parts of the world and how do you find +the explosive devices Left Behind when + + align:start position:0% +the explosive devices Left Behind when + + + align:start position:0% +the explosive devices Left Behind when +the war is over so if you are Stephanie + + align:start position:0% +the war is over so if you are Stephanie + + + align:start position:0% +the war is over so if you are Stephanie +um you use Vesper that's what you do to + + align:start position:0% +um you use Vesper that's what you do to + + + align:start position:0% +um you use Vesper that's what you do to +find those explosives so in her own + + align:start position:0% +find those explosives so in her own + + + align:start position:0% +find those explosives so in her own +words now I'm G to tell you or she's + + align:start position:0% +words now I'm G to tell you or she's + + + align:start position:0% +words now I'm G to tell you or she's +going to tell you why Vesper which she + + align:start position:0% +going to tell you why Vesper which she + + + align:start position:0% +going to tell you why Vesper which she +calls + + align:start position:0% +calls + + + align:start position:0% +calls +vspr because she can say that better + + align:start position:0% +vspr because she can say that better + + + align:start position:0% +vspr because she can say that better +than I can um to uh find explosives my + + align:start position:0% +than I can um to uh find explosives my + + + align:start position:0% +than I can um to uh find explosives my +name is Stephanie s and I am a graduate + + align:start position:0% +name is Stephanie s and I am a graduate + + + align:start position:0% +name is Stephanie s and I am a graduate +student in Tim swaggers research group + + align:start position:0% +student in Tim swaggers research group + + + align:start position:0% +student in Tim swaggers research group +at MIT the research that we're perhaps + + align:start position:0% +at MIT the research that we're perhaps + + + align:start position:0% +at MIT the research that we're perhaps +the most well known for is for sensing + + align:start position:0% +the most well known for is for sensing + + + align:start position:0% +the most well known for is for sensing +explosives such as + + align:start position:0% +explosives such as + + + align:start position:0% +explosives such as +TNT new bigger better explosives have + + align:start position:0% +TNT new bigger better explosives have + + + align:start position:0% +TNT new bigger better explosives have +been developed and two of these are RDX + + align:start position:0% +been developed and two of these are RDX + + + align:start position:0% +been developed and two of these are RDX +and petn and these kind of have more + + align:start position:0% +and petn and these kind of have more + + + align:start position:0% +and petn and these kind of have more +bang for your buck if you will + + align:start position:0% +bang for your buck if you will + + + align:start position:0% +bang for your buck if you will +Unfortunately they have an even lower + + align:start position:0% +Unfortunately they have an even lower + + + align:start position:0% +Unfortunately they have an even lower +vapor pressure than TNT which means + + align:start position:0% +vapor pressure than TNT which means + + + align:start position:0% +vapor pressure than TNT which means +there's even less molecules of the + + align:start position:0% +there's even less molecules of the + + + align:start position:0% +there's even less molecules of the +explosive in the air and it makes them + + align:start position:0% +explosive in the air and it makes them + + + align:start position:0% +explosive in the air and it makes them +even harder to detect the dogs that they + + align:start position:0% +even harder to detect the dogs that they + + + align:start position:0% +even harder to detect the dogs that they +would send out are actually sensing + + align:start position:0% +would send out are actually sensing + + + align:start position:0% +would send out are actually sensing +cyclohexanone and acetone which are + + align:start position:0% +cyclohexanone and acetone which are + + + align:start position:0% +cyclohexanone and acetone which are +molecules that are used in the + + align:start position:0% +molecules that are used in the + + + align:start position:0% +molecules that are used in the +purification of these two + + align:start position:0% +purification of these two + + + align:start position:0% +purification of these two +explosives both cyclohexanone and + + align:start position:0% +explosives both cyclohexanone and + + + align:start position:0% +explosives both cyclohexanone and +acetone have a carbonal in them and this + + align:start position:0% +acetone have a carbonal in them and this + + + align:start position:0% +acetone have a carbonal in them and this +carbonal then can interact with a group + + align:start position:0% +carbonal then can interact with a group + + + align:start position:0% +carbonal then can interact with a group +known as the + + align:start position:0% +known as the + + + align:start position:0% +known as the +Ura we have two nitrogens connected to a + + align:start position:0% +Ura we have two nitrogens connected to a + + + align:start position:0% +Ura we have two nitrogens connected to a +carbon that has a double bond to an + + align:start position:0% +carbon that has a double bond to an + + + align:start position:0% +carbon that has a double bond to an +oxygen between them and these nitrogens + + align:start position:0% +oxygen between them and these nitrogens + + + align:start position:0% +oxygen between them and these nitrogens +have hydrogens on it that that can + + align:start position:0% +have hydrogens on it that that can + + + align:start position:0% +have hydrogens on it that that can +hydrogen bond with the acetone or the + + align:start position:0% +hydrogen bond with the acetone or the + + + align:start position:0% +hydrogen bond with the acetone or the +cyclohexanone that we're looking for + + align:start position:0% +cyclohexanone that we're looking for + + + align:start position:0% +cyclohexanone that we're looking for +what happens is that the lone pair from + + align:start position:0% +what happens is that the lone pair from + + + align:start position:0% +what happens is that the lone pair from +the carbonal reaches out and grabs those + + align:start position:0% +the carbonal reaches out and grabs those + + + align:start position:0% +the carbonal reaches out and grabs those +hydrogens and pulls them away from the + + align:start position:0% +hydrogens and pulls them away from the + + + align:start position:0% +hydrogens and pulls them away from the +nitrogens and this makes the nitrogen + + align:start position:0% +nitrogens and this makes the nitrogen + + + align:start position:0% +nitrogens and this makes the nitrogen +hydrogen bond more lone pair likee as it + + align:start position:0% +hydrogen bond more lone pair likee as it + + + align:start position:0% +hydrogen bond more lone pair likee as it +becomes more lone pair likee we see more + + align:start position:0% +becomes more lone pair likee we see more + + + align:start position:0% +becomes more lone pair likee we see more +repulsion between the lone pair like + + align:start position:0% +repulsion between the lone pair like + + + align:start position:0% +repulsion between the lone pair like +Bond of electrons and the neighboring + + align:start position:0% +Bond of electrons and the neighboring + + + align:start position:0% +Bond of electrons and the neighboring +bonds and by the espr Theory we know + + align:start position:0% +bonds and by the espr Theory we know + + + align:start position:0% +bonds and by the espr Theory we know +that this is going to cause the bond + + align:start position:0% +that this is going to cause the bond + + + align:start position:0% +that this is going to cause the bond +angle to become larger between the + + align:start position:0% +angle to become larger between the + + + align:start position:0% +angle to become larger between the +nitrogen hydrogen bond and the + + align:start position:0% +nitrogen hydrogen bond and the + + + align:start position:0% +nitrogen hydrogen bond and the +accompanying bonds and smaller between + + align:start position:0% +accompanying bonds and smaller between + + + align:start position:0% +accompanying bonds and smaller between +the other bonds around the nitrogen and + + align:start position:0% +the other bonds around the nitrogen and + + + align:start position:0% +the other bonds around the nitrogen and +this causes large scale changes in the + + align:start position:0% +this causes large scale changes in the + + + align:start position:0% +this causes large scale changes in the +polymer so we can see differences in the + + align:start position:0% +polymer so we can see differences in the + + + align:start position:0% +polymer so we can see differences in the +way in the large scale the polymer + + align:start position:0% +way in the large scale the polymer + + + align:start position:0% +way in the large scale the polymer +interacts with light as fluorescence so + + align:start position:0% +interacts with light as fluorescence so + + + align:start position:0% +interacts with light as fluorescence so +it will start to Glow or a refractive + + align:start position:0% +it will start to Glow or a refractive + + + align:start position:0% +it will start to Glow or a refractive +index change which is also a different + + align:start position:0% +index change which is also a different + + + align:start position:0% +index change which is also a different +way that the polymer interacts with + + align:start position:0% +way that the polymer interacts with + + + align:start position:0% +way that the polymer interacts with +light we have instruments that can very + + align:start position:0% +light we have instruments that can very + + + align:start position:0% +light we have instruments that can very +easily measure both fluorescence and + + align:start position:0% +easily measure both fluorescence and + + + align:start position:0% +easily measure both fluorescence and +refractive index and with these very + + align:start position:0% +refractive index and with these very + + + align:start position:0% +refractive index and with these very +easy signals we now know that our + + align:start position:0% +easy signals we now know that our + + + align:start position:0% +easy signals we now know that our +acetone or cyclohexanone and therefore + + align:start position:0% +acetone or cyclohexanone and therefore + + + align:start position:0% +acetone or cyclohexanone and therefore +the explosive is there for soldiers this + + align:start position:0% +the explosive is there for soldiers this + + + align:start position:0% +the explosive is there for soldiers this +is a really big deal in Iraq and + + align:start position:0% +is a really big deal in Iraq and + + + align:start position:0% +is a really big deal in Iraq and +Afghanistan there are Mine Fields and + + align:start position:0% +Afghanistan there are Mine Fields and + + + align:start position:0% +Afghanistan there are Mine Fields and +kind of improvised explosive devices + + align:start position:0% +kind of improvised explosive devices + + + align:start position:0% +kind of improvised explosive devices +almost everywhere and the soldiers over + + align:start position:0% +almost everywhere and the soldiers over + + + align:start position:0% +almost everywhere and the soldiers over +there really have to watch where they + + align:start position:0% +there really have to watch where they + + + align:start position:0% +there really have to watch where they +step so if we can come up with a + + align:start position:0% +step so if we can come up with a + + + align:start position:0% +step so if we can come up with a +handheld device and we have in the past + + align:start position:0% +handheld device and we have in the past + + + align:start position:0% +handheld device and we have in the past +come up with some and I'm hoping that my + + align:start position:0% +come up with some and I'm hoping that my + + + align:start position:0% +come up with some and I'm hoping that my +technology might in the future also go + + align:start position:0% +technology might in the future also go + + + align:start position:0% +technology might in the future also go +towards these types of devices that will + + align:start position:0% +towards these types of devices that will + + + align:start position:0% +towards these types of devices that will +be kind of attached to a robot and sent + + align:start position:0% +be kind of attached to a robot and sent + + + align:start position:0% +be kind of attached to a robot and sent +out to kind of sniff out the area before + + align:start position:0% +out to kind of sniff out the area before + + + align:start position:0% +out to kind of sniff out the area before +the soldiers go there you can really + + align:start position:0% +the soldiers go there you can really + + + align:start position:0% +the soldiers go there you can really +save a lot of the soldiers lives as well + + align:start position:0% +save a lot of the soldiers lives as well + + + align:start position:0% +save a lot of the soldiers lives as well +it's very cool to kind of do the + + align:start position:0% +it's very cool to kind of do the + + + align:start position:0% +it's very cool to kind of do the +Hands-On work in the chemistry + + align:start position:0% +Hands-On work in the chemistry + + + align:start position:0% +Hands-On work in the chemistry +laboratory and then know that what + + align:start position:0% +laboratory and then know that what + + + align:start position:0% +laboratory and then know that what +you've done at your bench will then one + + align:start position:0% +you've done at your bench will then one + + + align:start position:0% +you've done at your bench will then one +day be actually used by someone and + + align:start position:0% +day be actually used by someone and + + + align:start position:0% +day be actually used by someone and +potentially save their life + + align:start position:0% +potentially save their life + + + align:start position:0% +potentially save their life +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so back to + + align:start position:0% +so back to + + + align:start position:0% +so back to +Vesper and loone pairs let's look at + + align:start position:0% +Vesper and loone pairs let's look at + + + align:start position:0% +Vesper and loone pairs let's look at +some examples and think about the shapes + + align:start position:0% +some examples and think about the shapes + + + align:start position:0% +some examples and think about the shapes +we've seen some of these already but + + align:start position:0% +we've seen some of these already but + + + align:start position:0% +we've seen some of these already but +let's look at some more so now we can + + align:start position:0% +let's look at some more so now we can + + + align:start position:0% +let's look at some more so now we can +have ax2 e SN number of three so two + + align:start position:0% +have ax2 e SN number of three so two + + + align:start position:0% +have ax2 e SN number of three so two +bonded atoms one lone pair this has bent + + align:start position:0% +bonded atoms one lone pair this has bent + + + align:start position:0% +bonded atoms one lone pair this has bent +geometry + + align:start position:0% +geometry + + + align:start position:0% +geometry +but again think about this lone pair now + + align:start position:0% +but again think about this lone pair now + + + align:start position:0% +but again think about this lone pair now +we're going to talk about the Angles and + + align:start position:0% +we're going to talk about the Angles and + + + align:start position:0% +we're going to talk about the Angles and +when we're talking about angles in this + + align:start position:0% +when we're talking about angles in this + + + align:start position:0% +when we're talking about angles in this +class we're talking about the angles + + align:start position:0% +class we're talking about the angles + + + align:start position:0% +class we're talking about the angles +between the bonded atoms so the angle + + align:start position:0% +between the bonded atoms so the angle + + + align:start position:0% +between the bonded atoms so the angle +from the lone pair down is going to be + + align:start position:0% +from the lone pair down is going to be + + + align:start position:0% +from the lone pair down is going to be +bigger because the lone pair is really + + align:start position:0% +bigger because the lone pair is really + + + align:start position:0% +bigger because the lone pair is really +repulsive but we're going to be thinking + + align:start position:0% +repulsive but we're going to be thinking + + + align:start position:0% +repulsive but we're going to be thinking +about the angle between the atoms you + + align:start position:0% +about the angle between the atoms you + + + align:start position:0% +about the angle between the atoms you +see so when we ask about angle we're + + align:start position:0% +see so when we ask about angle we're + + + align:start position:0% +see so when we ask about angle we're +asking about this angle between one + + align:start position:0% +asking about this angle between one + + + align:start position:0% +asking about this angle between one +bonded atom Central atom and the other + + align:start position:0% +bonded atom Central atom and the other + + + align:start position:0% +bonded atom Central atom and the other +bonded atom so this really this lone + + align:start position:0% +bonded atom so this really this lone + + + align:start position:0% +bonded atom so this really this lone +pair doesn't look that repulsive so I + + align:start position:0% +pair doesn't look that repulsive so I + + + align:start position:0% +pair doesn't look that repulsive so I +just want you to sort of think more + + align:start position:0% +just want you to sort of think more + + + align:start position:0% +just want you to sort of think more +about + + align:start position:0% +about + + + align:start position:0% +about +this so keep this in mind this is really + + align:start position:0% +this so keep this in mind this is really + + + align:start position:0% +this so keep this in mind this is really +more what a messy roommate is all about + + align:start position:0% +more what a messy roommate is all about + + + align:start position:0% +more what a messy roommate is all about +so if this is your lone pair pressing + + align:start position:0% +so if this is your lone pair pressing + + + align:start position:0% +so if this is your lone pair pressing +down on those bonds what do you expect + + align:start position:0% +down on those bonds what do you expect + + + align:start position:0% +down on those bonds what do you expect +the angle is going to + + align:start position:0% +the angle is going to + + + align:start position:0% +the angle is going to +be what's the angle in the normal case + + align:start position:0% + + + + align:start position:0% + +first so we have 120 bonding oh and now + + align:start position:0% +first so we have 120 bonding oh and now + + + align:start position:0% +first so we have 120 bonding oh and now +think and actually that's a clicker + + align:start position:0% +think and actually that's a clicker + + + align:start position:0% +think and actually that's a clicker +question think about what the answer is + + align:start position:0% +question think about what the answer is + + + align:start position:0% +question think about what the answer is +going to be we talked about the + + align:start position:0% + + + + align:start position:0% + +normal all right 10 more 10 more + + align:start position:0% + + + + align:start position:0% + +seconds all right yes less than + + align:start position:0% +seconds all right yes less than + + + align:start position:0% +seconds all right yes less than +120 so you don't know exactly you can't + + align:start position:0% +120 so you don't know exactly you can't + + + align:start position:0% +120 so you don't know exactly you can't +say oh that's going to be + + align:start position:0% +say oh that's going to be + + + align:start position:0% +say oh that's going to be +118.5 or something but you can say less + + align:start position:0% +118.5 or something but you can say less + + + align:start position:0% +118.5 or something but you can say less +than 120 that's the that's how you would + + align:start position:0% +than 120 that's the that's how you would + + + align:start position:0% +than 120 that's the that's how you would +express it and I'll just remind myself + + align:start position:0% +express it and I'll just remind myself + + + align:start position:0% +express it and I'll just remind myself +to say if you like these model kits and + + align:start position:0% +to say if you like these model kits and + + + align:start position:0% +to say if you like these model kits and +want your own some toothpicks and + + align:start position:0% +want your own some toothpicks and + + + align:start position:0% +want your own some toothpicks and +gumdrops can create some awesome Vesper + + align:start position:0% +gumdrops can create some awesome Vesper + + + align:start position:0% +gumdrops can create some awesome Vesper +model kits and we'll try to bring some + + align:start position:0% +model kits and we'll try to bring some + + + align:start position:0% +model kits and we'll try to bring some +of these into a recitation for people + + align:start position:0% +of these into a recitation for people + + + align:start position:0% +of these into a recitation for people +who want to have gumdrops and toothpicks + + align:start position:0% +who want to have gumdrops and toothpicks + + + align:start position:0% +who want to have gumdrops and toothpicks +for making + + align:start position:0% +for making + + + align:start position:0% +for making +models okay so let's keep going going so + + align:start position:0% +models okay so let's keep going going so + + + align:start position:0% +models okay so let's keep going going so +now we have our tetrahedral based system + + align:start position:0% +now we have our tetrahedral based system + + + align:start position:0% +now we have our tetrahedral based system +ax um and but we have + + align:start position:0% +ax um and but we have + + + align:start position:0% +ax um and but we have +ax 3 + + align:start position:0% +ax 3 + + + align:start position:0% +ax 3 +e and an SN number of four So based on T + + align:start position:0% +e and an SN number of four So based on T + + + align:start position:0% +e and an SN number of four So based on T +on uh on + + align:start position:0% +on uh on + + + align:start position:0% +on uh on +tetrahedral and so here now we have + + align:start position:0% +tetrahedral and so here now we have + + + align:start position:0% +tetrahedral and so here now we have +trigonal paramal so we have a bunch this + + align:start position:0% +trigonal paramal so we have a bunch this + + + align:start position:0% +trigonal paramal so we have a bunch this +is why it's confusing it's not bip + + align:start position:0% +is why it's confusing it's not bip + + + align:start position:0% +is why it's confusing it's not bip +paramal there's only one pyramid here + + align:start position:0% +paramal there's only one pyramid here + + + align:start position:0% +paramal there's only one pyramid here +and it looks like a triangle so trigonal + + align:start position:0% +and it looks like a triangle so trigonal + + + align:start position:0% +and it looks like a triangle so trigonal +paramal and now what are the angles + + align:start position:0% +paramal and now what are the angles + + + align:start position:0% +paramal and now what are the angles +going to be and you can just yell this + + align:start position:0% +going to be and you can just yell this + + + align:start position:0% +going to be and you can just yell this +one + + align:start position:0% +one + + + align:start position:0% +one +out yeah lesson + + align:start position:0% +out yeah lesson + + + align:start position:0% +out yeah lesson +109.5 and now let's keep going and we + + align:start position:0% +109.5 and now let's keep going and we + + + align:start position:0% +109.5 and now let's keep going and we +have another clicker + + align:start position:0% + + + + align:start position:0% + +question all right 10 more seconds + + align:start position:0% + + + + align:start position:0% + +okay so uh so the trick here was to + + align:start position:0% +okay so uh so the trick here was to + + + align:start position:0% +okay so uh so the trick here was to +think about the parent geometry of the + + align:start position:0% +think about the parent geometry of the + + + align:start position:0% +think about the parent geometry of the +system and so this is the parent + + align:start position:0% +system and so this is the parent + + + align:start position:0% +system and so this is the parent +geometry is the tetrahedral system and + + align:start position:0% +geometry is the tetrahedral system and + + + align:start position:0% +geometry is the tetrahedral system and +we know that because it has an SN number + + align:start position:0% +we know that because it has an SN number + + + align:start position:0% +we know that because it has an SN number +of four and so when you have an SN + + align:start position:0% +of four and so when you have an SN + + + align:start position:0% +of four and so when you have an SN +number of four then it's going to be + + align:start position:0% +number of four then it's going to be + + + align:start position:0% +number of four then it's going to be +less than + + align:start position:0% +less than + + + align:start position:0% +less than +109.5 and this is called a bent geometry + + align:start position:0% +109.5 and this is called a bent geometry + + + align:start position:0% +109.5 and this is called a bent geometry +so again you can think about it with in + + align:start position:0% +so again you can think about it with in + + + align:start position:0% +so again you can think about it with in +terms of those uh you know if you have + + align:start position:0% +terms of those uh you know if you have + + + align:start position:0% +terms of those uh you know if you have +some whole cans those lone pairs are + + align:start position:0% +some whole cans those lone pairs are + + + align:start position:0% +some whole cans those lone pairs are +pressing down on the bonds and + + align:start position:0% +pressing down on the bonds and + + + align:start position:0% +pressing down on the bonds and +compressing them so it's less than 109.5 + + align:start position:0% +compressing them so it's less than 109.5 + + + align:start position:0% +compressing them so it's less than 109.5 +I just teach chemistry because I like to + + align:start position:0% +I just teach chemistry because I like to + + + align:start position:0% +I just teach chemistry because I like to +buy whole cans and have a justification + + align:start position:0% +buy whole cans and have a justification + + + align:start position:0% +buy whole cans and have a justification +for it it's really the bottom line okay + + align:start position:0% +for it it's really the bottom line okay + + + align:start position:0% +for it it's really the bottom line okay +so if we keep going now we have our + + align:start position:0% +so if we keep going now we have our + + + align:start position:0% +so if we keep going now we have our +friend seesaw which you're never going + + align:start position:0% +friend seesaw which you're never going + + + align:start position:0% +friend seesaw which you're never going +to + + align:start position:0% +to + + + align:start position:0% +to +forget and I'll rebuild my my uh oops + + align:start position:0% +forget and I'll rebuild my my uh oops + + + align:start position:0% +forget and I'll rebuild my my uh oops +wrong one rebuild my seesaw over + + align:start position:0% +wrong one rebuild my seesaw over + + + align:start position:0% +wrong one rebuild my seesaw over +here so now what are the angles + + align:start position:0% +here so now what are the angles + + + align:start position:0% +here so now what are the angles +here there's two of them think about the + + align:start position:0% +here there's two of them think about the + + + align:start position:0% +here there's two of them think about the +uh the equatorial + + align:start position:0% +uh the equatorial + + + align:start position:0% +uh the equatorial +angles yep I'm hearing it less than 120 + + align:start position:0% +angles yep I'm hearing it less than 120 + + + align:start position:0% +angles yep I'm hearing it less than 120 +and the axial would be less than 90 so + + align:start position:0% +and the axial would be less than 90 so + + + align:start position:0% +and the axial would be less than 90 so +the lone pair is pressing down both on + + align:start position:0% +the lone pair is pressing down both on + + + align:start position:0% +the lone pair is pressing down both on +the 90 and on the 120 it's probably more + + align:start position:0% +the 90 and on the 120 it's probably more + + + align:start position:0% +the 90 and on the 120 it's probably more +repulsive for the 90 but all you have to + + align:start position:0% +repulsive for the 90 but all you have to + + + align:start position:0% +repulsive for the 90 but all you have to +do is say less than for both of them so + + align:start position:0% +do is say less than for both of them so + + + align:start position:0% +do is say less than for both of them so +the trick is just think about the parent + + align:start position:0% +the trick is just think about the parent + + + align:start position:0% +the trick is just think about the parent +geometry what are the angles in the + + align:start position:0% +geometry what are the angles in the + + + align:start position:0% +geometry what are the angles in the +parent geometry and then it's less + + align:start position:0% + + + + align:start position:0% + +than um and if we keep going with this + + align:start position:0% +than um and if we keep going with this + + + align:start position:0% +than um and if we keep going with this +we had our t-shaped + + align:start position:0% +we had our t-shaped + + + align:start position:0% +we had our t-shaped +molecule as well so we added another + + align:start position:0% +molecule as well so we added another + + + align:start position:0% +molecule as well so we added another +lone pair to our sn5 case and what's the + + align:start position:0% +lone pair to our sn5 case and what's the + + + align:start position:0% +lone pair to our sn5 case and what's the +angle now going to be with those two + + align:start position:0% +angle now going to be with those two + + + align:start position:0% +angle now going to be with those two +loone + + align:start position:0% +loone + + + align:start position:0% +loone +pairs less than less than 90 right all + + align:start position:0% +pairs less than less than 90 right all + + + align:start position:0% +pairs less than less than 90 right all +right + + align:start position:0% +right + + + align:start position:0% +right +so there are so many possibilities for + + align:start position:0% +so there are so many possibilities for + + + align:start position:0% +so there are so many possibilities for +loan + + align:start position:0% + + + + align:start position:0% + +pairs if we add yet another loone pair + + align:start position:0% +pairs if we add yet another loone pair + + + align:start position:0% +pairs if we add yet another loone pair +to the system what's my + + align:start position:0% +to the system what's my + + + align:start position:0% +to the system what's my +geometry yep so this is going to be now + + align:start position:0% +geometry yep so this is going to be now + + + align:start position:0% +geometry yep so this is going to be now +a linear + + align:start position:0% +a linear + + + align:start position:0% +a linear +geometry and what's the angle going to + + align:start position:0% +geometry and what's the angle going to + + + align:start position:0% +geometry and what's the angle going to +be yeah it's just going to be 180 so we + + align:start position:0% +be yeah it's just going to be 180 so we + + + align:start position:0% +be yeah it's just going to be 180 so we +don't have a less than here because + + align:start position:0% +don't have a less than here because + + + align:start position:0% +don't have a less than here because +whatever way it would bend it would be + + align:start position:0% +whatever way it would bend it would be + + + align:start position:0% +whatever way it would bend it would be +just moving toward more repulsive loone + + align:start position:0% +just moving toward more repulsive loone + + + align:start position:0% +just moving toward more repulsive loone +pairs so there's no way you can minimize + + align:start position:0% +pairs so there's no way you can minimize + + + align:start position:0% +pairs so there's no way you can minimize +the repulsion in this case so it's just + + align:start position:0% +the repulsion in this case so it's just + + + align:start position:0% +the repulsion in this case so it's just +going to be a linear molecule + + align:start position:0% + + + + align:start position:0% + +so now we're going to move into our + + align:start position:0% +so now we're going to move into our + + + align:start position:0% +so now we're going to move into our +sn6 category and we're going to talk + + align:start position:0% +sn6 category and we're going to talk + + + align:start position:0% +sn6 category and we're going to talk +about a shape that we haven't talked + + align:start position:0% +about a shape that we haven't talked + + + align:start position:0% +about a shape that we haven't talked +about yet + + align:start position:0% +about yet + + + align:start position:0% +about yet +so based on this what happens we have + + align:start position:0% +so based on this what happens we have + + + align:start position:0% +so based on this what happens we have +our parent geometry of octahedral and so + + align:start position:0% +our parent geometry of octahedral and so + + + align:start position:0% +our parent geometry of octahedral and so +this has six bonded atoms sn6 but now + + align:start position:0% +this has six bonded atoms sn6 but now + + + align:start position:0% +this has six bonded atoms sn6 but now +we're going to take off one of the + + align:start position:0% +we're going to take off one of the + + + align:start position:0% +we're going to take off one of the +bonds put it the same as the figure + + align:start position:0% +bonds put it the same as the figure + + + align:start position:0% +bonds put it the same as the figure +we're going to going to take off one of + + align:start position:0% +we're going to going to take off one of + + + align:start position:0% +we're going to going to take off one of +the bonds and put on a lone pair and + + align:start position:0% +the bonds and put on a lone pair and + + + align:start position:0% +the bonds and put on a lone pair and +this is called Square paramal because + + align:start position:0% +this is called Square paramal because + + + align:start position:0% +this is called Square paramal because +you have this Square here in your axial + + align:start position:0% +you have this Square here in your axial + + + align:start position:0% +you have this Square here in your axial +it looks like a square but when you + + align:start position:0% +it looks like a square but when you + + + align:start position:0% +it looks like a square but when you +consider you have an atom on top coming + + align:start position:0% +consider you have an atom on top coming + + + align:start position:0% +consider you have an atom on top coming +down to these + + align:start position:0% +down to these + + + align:start position:0% +down to these +four atoms on the side that again looks + + align:start position:0% +four atoms on the side that again looks + + + align:start position:0% +four atoms on the side that again looks +like a pyramid so this is square + + align:start position:0% +like a pyramid so this is square + + + align:start position:0% +like a pyramid so this is square +paramal and what angle do you think + + align:start position:0% +paramal and what angle do you think + + + align:start position:0% +paramal and what angle do you think +you're going to have here for these + + align:start position:0% +you're going to have here for these + + + align:start position:0% +you're going to have here for these +bonded + + align:start position:0% +bonded + + + align:start position:0% +bonded +atoms yep that'll be less than + + align:start position:0% +atoms yep that'll be less than + + + align:start position:0% +atoms yep that'll be less than +90 all right so we can keep going and we + + align:start position:0% +90 all right so we can keep going and we + + + align:start position:0% +90 all right so we can keep going and we +saw this one before if we take off + + align:start position:0% +saw this one before if we take off + + + align:start position:0% +saw this one before if we take off +another bonded electron and put in a + + align:start position:0% +another bonded electron and put in a + + + align:start position:0% +another bonded electron and put in a +second lone pair as we saw before those + + align:start position:0% +second lone pair as we saw before those + + + align:start position:0% +second lone pair as we saw before those +lone pairs want to be far apart from + + align:start position:0% +lone pairs want to be far apart from + + + align:start position:0% +lone pairs want to be far apart from +each other as they can so one goes on + + align:start position:0% +each other as they can so one goes on + + + align:start position:0% +each other as they can so one goes on +top one goes on the bottom and this was + + align:start position:0% +top one goes on the bottom and this was + + + align:start position:0% +top one goes on the bottom and this was +our Square planer geometry because it's + + align:start position:0% +our Square planer geometry because it's + + + align:start position:0% +our Square planer geometry because it's +a square and it's planer now what do you + + align:start position:0% +a square and it's planer now what do you + + + align:start position:0% +a square and it's planer now what do you +think the angles are + + align:start position:0% +think the angles are + + + align:start position:0% +think the angles are +90 right there's no there's nowhere to + + align:start position:0% +90 right there's no there's nowhere to + + + align:start position:0% +90 right there's no there's nowhere to +escape when you have a messy roommate on + + align:start position:0% +escape when you have a messy roommate on + + + align:start position:0% +escape when you have a messy roommate on +top and a Ry roommate on the bottom if + + align:start position:0% +top and a Ry roommate on the bottom if + + + align:start position:0% +top and a Ry roommate on the bottom if +you're in a triple between messy + + align:start position:0% +you're in a triple between messy + + + align:start position:0% +you're in a triple between messy +roommates there's just nothing you can + + align:start position:0% +roommates there's just nothing you can + + + align:start position:0% +roommates there's just nothing you can +do um and you can't you can't minimize + + align:start position:0% +do um and you can't you can't minimize + + + align:start position:0% +do um and you can't you can't minimize +the repulsion at all you just have to + + align:start position:0% +the repulsion at all you just have to + + + align:start position:0% +the repulsion at all you just have to +live with it okay so if we keep going + + align:start position:0% +live with it okay so if we keep going + + + align:start position:0% +live with it okay so if we keep going +again and now we're going to add another + + align:start position:0% +again and now we're going to add another + + + align:start position:0% +again and now we're going to add another +lone pair and it really doesn't matter + + align:start position:0% +lone pair and it really doesn't matter + + + align:start position:0% +lone pair and it really doesn't matter +where we put that it's all equivalent + + align:start position:0% +where we put that it's all equivalent + + + align:start position:0% +where we put that it's all equivalent +and it comes up with a shape that's + + align:start position:0% +and it comes up with a shape that's + + + align:start position:0% +and it comes up with a shape that's +t-shaped again that makes sense when you + + align:start position:0% +t-shaped again that makes sense when you + + + align:start position:0% +t-shaped again that makes sense when you +look at the structure and now what do + + align:start position:0% +look at the structure and now what do + + + align:start position:0% +look at the structure and now what do +you think the angles + + align:start position:0% +you think the angles + + + align:start position:0% +you think the angles +are less than 90 and you would be + + align:start position:0% +are less than 90 and you would be + + + align:start position:0% +are less than 90 and you would be +correct in that all right so if we put + + align:start position:0% +correct in that all right so if we put + + + align:start position:0% +correct in that all right so if we put +on yet one more lone pair and take off a + + align:start position:0% +on yet one more lone pair and take off a + + + align:start position:0% +on yet one more lone pair and take off a +bonded electron or take off one more + + align:start position:0% +bonded electron or take off one more + + + align:start position:0% +bonded electron or take off one more +bonded at bonded atom and put on + + align:start position:0% +bonded at bonded atom and put on + + + align:start position:0% +bonded at bonded atom and put on +electron what's our + + align:start position:0% +electron what's our + + + align:start position:0% +electron what's our +geometry right so we have this structure + + align:start position:0% +geometry right so we have this structure + + + align:start position:0% +geometry right so we have this structure +it's linear 180 no place to go so we + + align:start position:0% +it's linear 180 no place to go so we + + + align:start position:0% +it's linear 180 no place to go so we +keep going far enough we come back to + + align:start position:0% +keep going far enough we come back to + + + align:start position:0% +keep going far enough we come back to +linear a + + align:start position:0% + + + + align:start position:0% + +lot now let's just look at a couple um + + align:start position:0% +lot now let's just look at a couple um + + + align:start position:0% +lot now let's just look at a couple um +more some real life examples of + + align:start position:0% +more some real life examples of + + + align:start position:0% +more some real life examples of +molecules and think about their think + + align:start position:0% +molecules and think about their think + + + align:start position:0% +molecules and think about their think +about their geometries and shapes have a + + align:start position:0% +about their geometries and shapes have a + + + align:start position:0% +about their geometries and shapes have a +couple more clicker questions um so + + align:start position:0% +couple more clicker questions um so + + + align:start position:0% +couple more clicker questions um so +let's start with our friend + + align:start position:0% +let's start with our friend + + + align:start position:0% +let's start with our friend +water and I had water + + align:start position:0% +water and I had water + + + align:start position:0% +water and I had water +here so now let's think about what the + + align:start position:0% +here so now let's think about what the + + + align:start position:0% +here so now let's think about what the +formula type is going to be for water + + align:start position:0% +formula type is going to be for water + + + align:start position:0% +formula type is going to be for water +and what's our formula + + align:start position:0% + + + + align:start position:0% + +type + + align:start position:0% +type + + + align:start position:0% +type +ax y a X2 E2 two bonded atoms two lone + + align:start position:0% +ax y a X2 E2 two bonded atoms two lone + + + align:start position:0% +ax y a X2 E2 two bonded atoms two lone +pairs s a number of four and do you + + align:start position:0% +pairs s a number of four and do you + + + align:start position:0% +pairs s a number of four and do you +remember what this geometry is called + + align:start position:0% +remember what this geometry is called + + + align:start position:0% +remember what this geometry is called +bent yeah and this explains then what we + + align:start position:0% +bent yeah and this explains then what we + + + align:start position:0% +bent yeah and this explains then what we +talked about before that this is a polar + + align:start position:0% +talked about before that this is a polar + + + align:start position:0% +talked about before that this is a polar +molecule so these are polar bonds + + align:start position:0% +molecule so these are polar bonds + + + align:start position:0% +molecule so these are polar bonds +between the oxygen and the hydro + + align:start position:0% +between the oxygen and the hydro + + + align:start position:0% +between the oxygen and the hydro +hydrogen and but in this case it's not a + + align:start position:0% +hydrogen and but in this case it's not a + + + align:start position:0% +hydrogen and but in this case it's not a +linear molecule it's a bent molecule so + + align:start position:0% +linear molecule it's a bent molecule so + + + align:start position:0% +linear molecule it's a bent molecule so +it creates a net dipole and so that + + align:start position:0% +it creates a net dipole and so that + + + align:start position:0% +it creates a net dipole and so that +makes it a polar molecule and if water + + align:start position:0% +makes it a polar molecule and if water + + + align:start position:0% +makes it a polar molecule and if water +had any other shape and was not a polar + + align:start position:0% +had any other shape and was not a polar + + + align:start position:0% +had any other shape and was not a polar +molecule then life would be entirely + + align:start position:0% +molecule then life would be entirely + + + align:start position:0% +molecule then life would be entirely +different because water is the solvent + + align:start position:0% +different because water is the solvent + + + align:start position:0% +different because water is the solvent +of life so uh this shape pretty pretty + + align:start position:0% +of life so uh this shape pretty pretty + + + align:start position:0% +of life so uh this shape pretty pretty +important for anything actually they + + align:start position:0% +important for anything actually they + + + align:start position:0% +important for anything actually they +researched on what what medical doctors + + align:start position:0% +researched on what what medical doctors + + + align:start position:0% +researched on what what medical doctors +thought was the most important topic to + + align:start position:0% +thought was the most important topic to + + + align:start position:0% +thought was the most important topic to +learn as an undergraduate and Premed + + align:start position:0% +learn as an undergraduate and Premed + + + align:start position:0% +learn as an undergraduate and Premed +education and the number one topic that + + align:start position:0% +education and the number one topic that + + + align:start position:0% +education and the number one topic that +was most important was water there and + + align:start position:0% +was most important was water there and + + + align:start position:0% +was most important was water there and +you just learned about it okay so we + + align:start position:0% +you just learned about it okay so we + + + align:start position:0% +you just learned about it okay so we +keep going now and you have to answer a + + align:start position:0% +keep going now and you have to answer a + + + align:start position:0% +keep going now and you have to answer a +lot of things about this on a clicker + + align:start position:0% +lot of things about this on a clicker + + + align:start position:0% +lot of things about this on a clicker +question + + align:start position:0% + + + + align:start position:0% + +all right just 10 more seconds we got to + + align:start position:0% +all right just 10 more seconds we got to + + + align:start position:0% +all right just 10 more seconds we got to +finish our hand + + align:start position:0% + + + + align:start position:0% + +out all right so let's go take a look at + + align:start position:0% +out all right so let's go take a look at + + + align:start position:0% +out all right so let's go take a look at +this one + + align:start position:0% +this one + + + align:start position:0% +this one +and fill it + + align:start position:0% +and fill it + + + align:start position:0% +and fill it +in so we have our + + align:start position:0% +in so we have our + + + align:start position:0% +in so we have our +ax4 which is an sn5 system because we + + align:start position:0% +ax4 which is an sn5 system because we + + + align:start position:0% +ax4 which is an sn5 system because we +have one + + align:start position:0% +have one + + + align:start position:0% +have one +e and then we have our seesaw + + align:start position:0% +e and then we have our seesaw + + + align:start position:0% +e and then we have our seesaw +geometry all right so let's just fill in + + align:start position:0% +geometry all right so let's just fill in + + + align:start position:0% +geometry all right so let's just fill in +the in the rest here and see who's won + + align:start position:0% +the in the rest here and see who's won + + + align:start position:0% +the in the rest here and see who's won +the clicker competition so for the next + + align:start position:0% +the clicker competition so for the next + + + align:start position:0% +the clicker competition so for the next +system we have BR now it's it's expanded + + align:start position:0% +system we have BR now it's it's expanded + + + align:start position:0% +system we have BR now it's it's expanded +so we have ax3 E2 sn5 we've added + + align:start position:0% +so we have ax3 E2 sn5 we've added + + + align:start position:0% +so we have ax3 E2 sn5 we've added +another lone pair and now this makes a + + align:start position:0% +another lone pair and now this makes a + + + align:start position:0% +another lone pair and now this makes a +t-shape but it's kind of a little bent + + align:start position:0% +t-shape but it's kind of a little bent + + + align:start position:0% +t-shape but it's kind of a little bent +t-shape because of the repulsion we come + + align:start position:0% +t-shape because of the repulsion we come + + + align:start position:0% +t-shape because of the repulsion we come +down we have ax2 E5 sn5 we've added + + align:start position:0% +down we have ax2 E5 sn5 we've added + + + align:start position:0% +down we have ax2 E5 sn5 we've added +three more with Xenon Xenon is expanded + + align:start position:0% +three more with Xenon Xenon is expanded + + + align:start position:0% +three more with Xenon Xenon is expanded +here we have our linear shape we also + + align:start position:0% +here we have our linear shape we also + + + align:start position:0% +here we have our linear shape we also +have Xenon with four things + + align:start position:0% +have Xenon with four things + + + align:start position:0% +have Xenon with four things +um bound and if we did the Lewis + + align:start position:0% +um bound and if we did the Lewis + + + align:start position:0% +um bound and if we did the Lewis +structure of that we'd realize there's + + align:start position:0% +structure of that we'd realize there's + + + align:start position:0% +structure of that we'd realize there's +lone pairs on the top and the bottom ax4 + + align:start position:0% +lone pairs on the top and the bottom ax4 + + + align:start position:0% +lone pairs on the top and the bottom ax4 +E2 + + align:start position:0% +E2 + + + align:start position:0% +E2 +sn6 and this is our Square planer + + align:start position:0% +sn6 and this is our Square planer + + + align:start position:0% +sn6 and this is our Square planer +geometry so you can predict a lot about + + align:start position:0% +geometry so you can predict a lot about + + + align:start position:0% +geometry so you can predict a lot about +just doing a Lewis structure thinking + + align:start position:0% +just doing a Lewis structure thinking + + + align:start position:0% +just doing a Lewis structure thinking +about where the loan pairs You can + + align:start position:0% +about where the loan pairs You can + + + align:start position:0% +about where the loan pairs You can +predict geometries and let's see who has + + align:start position:0% +predict geometries and let's see who has + + + align:start position:0% +predict geometries and let's see who has +won + + align:start position:0% + + + + align:start position:0% + +today we have an upset + + align:start position:0% + + + + align:start position:0% + +all right + + align:start position:0% +all right + + + align:start position:0% +all right +Sam all right see everybody on Monday \ No newline at end of file diff --git a/JneQrFoLq18.txt b/JneQrFoLq18.txt new file mode 100644 index 0000000000000000000000000000000000000000..ba2111d5663468394f54dd7c8353cad7333c0c81 --- /dev/null +++ b/JneQrFoLq18.txt @@ -0,0 +1,10591 @@ +align:start position:0% + +let's get started uh welcome back 21m + + align:start position:0% +let's get started uh welcome back 21m + + + align:start position:0% +let's get started uh welcome back 21m +383 computational music theory and + + align:start position:0% +383 computational music theory and + + + align:start position:0% +383 computational music theory and +Analysis went through probably one of + + align:start position:0% +Analysis went through probably one of + + + align:start position:0% +Analysis went through probably one of +the most slide heavy one of the fastest + + align:start position:0% +the most slide heavy one of the fastest + + + align:start position:0% +the most slide heavy one of the fastest +classes ever on Wednesday that I'll be + + align:start position:0% +classes ever on Wednesday that I'll be + + + align:start position:0% +classes ever on Wednesday that I'll be +doing uh this semester today we're going + + align:start position:0% +doing uh this semester today we're going + + + align:start position:0% +doing uh this semester today we're going +to switch gears we're going to do one of + + align:start position:0% +to switch gears we're going to do one of + + + align:start position:0% +to switch gears we're going to do one of +the least Tech uh heavy classes in this + + align:start position:0% +the least Tech uh heavy classes in this + + + align:start position:0% +the least Tech uh heavy classes in this +semester and then we'll probably keep + + align:start position:0% +semester and then we'll probably keep + + + align:start position:0% +semester and then we'll probably keep +going back and forth this is the only + + align:start position:0% +going back and forth this is the only + + + align:start position:0% +going back and forth this is the only +one that in my particular notes it for + + align:start position:0% +one that in my particular notes it for + + + align:start position:0% +one that in my particular notes it for +my lecture it says mike Don't Panic + + align:start position:0% +my lecture it says mike Don't Panic + + + align:start position:0% +my lecture it says mike Don't Panic +there actually is no power point because + + align:start position:0% +there actually is no power point because + + + align:start position:0% +there actually is no power point because +I was panicking the other day when I was + + align:start position:0% +I was panicking the other day when I was + + + align:start position:0% +I was panicking the other day when I was +preparing this I was like wait wait wait + + align:start position:0% +preparing this I was like wait wait wait + + + align:start position:0% +preparing this I was like wait wait wait +wait I did I delete it no there is + + align:start position:0% +wait I did I delete it no there is + + + align:start position:0% +wait I did I delete it no there is +nothing because I want us to step back + + align:start position:0% +nothing because I want us to step back + + + align:start position:0% +nothing because I want us to step back +for a little bit and think about some of + + align:start position:0% +for a little bit and think about some of + + + align:start position:0% +for a little bit and think about some of +the things and do some work on um some + + align:start position:0% +the things and do some work on um some + + + align:start position:0% +the things and do some work on um some +of the things to do with what we mean by + + align:start position:0% +of the things to do with what we mean by + + + align:start position:0% +of the things to do with what we mean by +music because various musical points + + align:start position:0% +music because various musical points + + + align:start position:0% +music because various musical points +because there's a lot of things that we + + align:start position:0% +because there's a lot of things that we + + + align:start position:0% +because there's a lot of things that we +can know that are um you know just sort + + align:start position:0% +can know that are um you know just sort + + + align:start position:0% +can know that are um you know just sort +of um uh just just sort of intuitively + + align:start position:0% +of um uh just just sort of intuitively + + + align:start position:0% +of um uh just just sort of intuitively +we all know what that is but then um we + + align:start position:0% +we all know what that is but then um we + + + align:start position:0% +we all know what that is but then um we +might not um you know we might not be + + align:start position:0% +might not um you know we might not be + + + align:start position:0% +might not um you know we might not be +able to explain it to a computer because + + align:start position:0% +able to explain it to a computer because + + + align:start position:0% +able to explain it to a computer because +computers are smart or computers are + + align:start position:0% +computers are smart or computers are + + + align:start position:0% +computers are smart or computers are +dumb what do you think shout it out dumb + + align:start position:0% +dumb what do you think shout it out dumb + + + align:start position:0% +dumb what do you think shout it out dumb +neither no neither dumb neither no no + + align:start position:0% +neither no neither dumb neither no no + + + align:start position:0% +neither no neither dumb neither no no +smart okay I think computers are really + + align:start position:0% +smart okay I think computers are really + + + align:start position:0% +smart okay I think computers are really +really dumb until we make them smart so + + align:start position:0% +really dumb until we make them smart so + + + align:start position:0% +really dumb until we make them smart so +or something like that great there's + + align:start position:0% +or something like that great there's + + + align:start position:0% +or something like that great there's +some people in the back that whose names + + align:start position:0% +some people in the back that whose names + + + align:start position:0% +some people in the back that whose names +I don't know could you take a sheet of + + align:start position:0% +I don't know could you take a sheet of + + + align:start position:0% +I don't know could you take a sheet of +paper you can also use your outline to + + align:start position:0% +paper you can also use your outline to + + + align:start position:0% +paper you can also use your outline to +put your name on it because uh the + + align:start position:0% +put your name on it because uh the + + + align:start position:0% +put your name on it because uh the +outlines for reading later and it's kind + + align:start position:0% +outlines for reading later and it's kind + + + align:start position:0% +outlines for reading later and it's kind +of nice that this way you have it for + + align:start position:0% +of nice that this way you have it for + + + align:start position:0% +of nice that this way you have it for +later and this way you won't um sort of + + align:start position:0% +later and this way you won't um sort of + + + align:start position:0% +later and this way you won't um sort of +get me if I go out of order right um + + align:start position:0% +get me if I go out of order right um + + + align:start position:0% +get me if I go out of order right um +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so I'm seeing who your names are can you + + align:start position:0% +so I'm seeing who your names are can you + + + align:start position:0% +so I'm seeing who your names are can you +take a second and at least the person + + align:start position:0% +take a second and at least the person + + + align:start position:0% +take a second and at least the person +you're sharing a table or sharing the + + align:start position:0% +you're sharing a table or sharing the + + + align:start position:0% +you're sharing a table or sharing the +invisible table with um and introduce + + align:start position:0% +invisible table with um and introduce + + + align:start position:0% +invisible table with um and introduce +yourself if you don't know that + + align:start position:0% +yourself if you don't know that + + + align:start position:0% +yourself if you don't know that +where okay now add into your + + align:start position:0% +where okay now add into your + + + align:start position:0% +where okay now add into your +conversation add into your conversation + + align:start position:0% +conversation add into your conversation + + + align:start position:0% +conversation add into your conversation +what you think a note is you can also + + align:start position:0% +what you think a note is you can also + + + align:start position:0% +what you think a note is you can also +keep getting to know each other the same + + align:start position:0% +keep getting to know each other the same + + + align:start position:0% +keep getting to know each other the same +time but what you think a note + + align:start position:0% + + + + align:start position:0% + +is okay I'm going to be asking you for + + align:start position:0% +is okay I'm going to be asking you for + + + align:start position:0% +is okay I'm going to be asking you for +for some definitions in a second but + + align:start position:0% +for some definitions in a second but + + + align:start position:0% +for some definitions in a second but +before we get to that um all I want you + + align:start position:0% +before we get to that um all I want you + + + align:start position:0% +before we get to that um all I want you +to do is take your definitions you've + + align:start position:0% +to do is take your definitions you've + + + align:start position:0% +to do is take your definitions you've +kind of got them first thing and you + + align:start position:0% +kind of got them first thing and you + + + align:start position:0% +kind of got them first thing and you +just got to count notes okay so I'm + + align:start position:0% +just got to count notes okay so I'm + + + align:start position:0% +just got to count notes okay so I'm +going to sing some things and you tell + + align:start position:0% +going to sing some things and you tell + + + align:start position:0% +going to sing some things and you tell +me how many notes I sing so write them + + align:start position:0% +me how many notes I sing so write them + + + align:start position:0% +me how many notes I sing so write them +down and then I'll ask them later + + align:start position:0% +down and then I'll ask them later + + + align:start position:0% +down and then I'll ask them later +um first + + align:start position:0% + + + + align:start position:0% + +set pretty easy right + + align:start position:0% + + + + align:start position:0% + +second + + align:start position:0% + + + + align:start position:0% + +one third + + align:start position:0% +one third + + + align:start position:0% +one third +[Music] + + align:start position:0% + + + + align:start position:0% + +one fourth one + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% + + + + align:start position:0% + +and fifth + + align:start position:0% + + + + align:start position:0% + +one great talk with your talk with your + + align:start position:0% +one great talk with your talk with your + + + align:start position:0% +one great talk with your talk with your +neighbor and see how many if you got + + align:start position:0% +neighbor and see how many if you got + + + align:start position:0% +neighbor and see how many if you got +answers that line up with each + + align:start position:0% +answers that line up with each + + + align:start position:0% +answers that line up with each +other okay let's let's come back + + align:start position:0% +other okay let's let's come back + + + align:start position:0% +other okay let's let's come back +together + + align:start position:0% +together + + + align:start position:0% +together +um let's come back together we have um + + align:start position:0% +um let's come back together we have um + + + align:start position:0% +um let's come back together we have um +uh I believe that the normal + + align:start position:0% +uh I believe that the normal + + + align:start position:0% +uh I believe that the normal +distribution of names in this class is + + align:start position:0% +distribution of names in this class is + + + align:start position:0% +distribution of names in this class is +kind of like the uh letters in the + + align:start position:0% +kind of like the uh letters in the + + + align:start position:0% +kind of like the uh letters in the +alphabet so we we'll start with J's I'll + + align:start position:0% +alphabet so we we'll start with J's I'll + + + align:start position:0% +alphabet so we we'll start with J's I'll +call who's the alphabetically first J is + + align:start position:0% +call who's the alphabetically first J is + + + align:start position:0% +call who's the alphabetically first J is +it + + align:start position:0% +it + + + align:start position:0% +it +Jason Jason um something something like + + align:start position:0% +Jason Jason um something something like + + + align:start position:0% +Jason Jason um something something like +and if I change the things I'm doing it + + align:start position:0% +and if I change the things I'm doing it + + + align:start position:0% +and if I change the things I'm doing it +accidentally because I don't remember + + align:start position:0% +accidentally because I don't remember + + + align:start position:0% +accidentally because I don't remember +what I saying but um the first + + align:start position:0% + + + + align:start position:0% + +one three notes three notes how many + + align:start position:0% +one three notes three notes how many + + + align:start position:0% +one three notes three notes how many +agree how many disagree + + align:start position:0% +agree how many disagree + + + align:start position:0% +agree how many disagree +agrees + + align:start position:0% +agrees + + + align:start position:0% +agrees +disagrees okay good that was the right + + align:start position:0% +disagrees okay good that was the right + + + align:start position:0% +disagrees okay good that was the right +answer I saying three notes good who's + + align:start position:0% +answer I saying three notes good who's + + + align:start position:0% +answer I saying three notes good who's +alphabetically next after Jason we have + + align:start position:0% +alphabetically next after Jason we have + + + align:start position:0% +alphabetically next after Jason we have +we have some Jonathan Jordans we have + + align:start position:0% +we have some Jonathan Jordans we have + + + align:start position:0% +we have some Jonathan Jordans we have +Jake oh okay you we went out sorry about + + align:start position:0% +Jake oh okay you we went out sorry about + + + align:start position:0% +Jake oh okay you we went out sorry about +that Jake um no even if we do Jacob or + + align:start position:0% +that Jake um no even if we do Jacob or + + + align:start position:0% +that Jake um no even if we do Jacob or +something it's still I'm still wrong + + align:start position:0% +something it's still I'm still wrong + + + align:start position:0% +something it's still I'm still wrong +okay + + align:start position:0% +okay + + + align:start position:0% +okay +Jake this is what I + + align:start position:0% + + + + align:start position:0% + +saying one note agree or disagree who + + align:start position:0% +saying one note agree or disagree who + + + align:start position:0% +saying one note agree or disagree who +agrees who + + align:start position:0% +agrees who + + + align:start position:0% +agrees who +disagrees good everybody is wrong I + + align:start position:0% +disagrees good everybody is wrong I + + + align:start position:0% +disagrees good everybody is wrong I +Sayang four + + align:start position:0% +Sayang four + + + align:start position:0% +Sayang four +um okay next note well next one I did I + + align:start position:0% +um okay next note well next one I did I + + + align:start position:0% +um okay next note well next one I did I +I went I went up + + align:start position:0% +I went I went up + + + align:start position:0% +I went I went up +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +right uh next up alphabetically would be + + align:start position:0% +right uh next up alphabetically would be + + + align:start position:0% +right uh next up alphabetically would be +uh Jonathan comes before John and comes + + align:start position:0% +uh Jonathan comes before John and comes + + + align:start position:0% +uh Jonathan comes before John and comes +before Jordan so + + align:start position:0% +before Jordan so + + + align:start position:0% +before Jordan so +Jonathan okay uh my was two notes two + + align:start position:0% +Jonathan okay uh my was two notes two + + + align:start position:0% +Jonathan okay uh my was two notes two +notes good uh who + + align:start position:0% +notes good uh who + + + align:start position:0% +notes good uh who +agrees okay we got some agrees um who + + align:start position:0% +agrees okay we got some agrees um who + + + align:start position:0% +agrees okay we got some agrees um who +dis + + align:start position:0% +dis + + + align:start position:0% +dis +agrees okay good we'll we'll continue + + align:start position:0% +agrees okay good we'll we'll continue + + + align:start position:0% +agrees okay good we'll we'll continue +with the J's on that John you disagreed + + align:start position:0% +with the J's on that John you disagreed + + + align:start position:0% +with the J's on that John you disagreed +what's the number you came up with uh I + + align:start position:0% +what's the number you came up with uh I + + + align:start position:0% +what's the number you came up with uh I +thought because you sing a lot I think + + align:start position:0% +thought because you sing a lot I think + + + align:start position:0% +thought because you sing a lot I think +you Sayang at least one note oh okay + + align:start position:0% +you Sayang at least one note oh okay + + + align:start position:0% +you Sayang at least one note oh okay +okay + + align:start position:0% +okay + + + align:start position:0% +okay +well greater than one note no greater + + align:start position:0% +well greater than one note no greater + + + align:start position:0% +well greater than one note no greater +than or equal to one note right okay so + + align:start position:0% +than or equal to one note right okay so + + + align:start position:0% +than or equal to one note right okay so +that that takes a little that's that's a + + align:start position:0% +that that takes a little that's that's a + + + align:start position:0% +that that takes a little that's that's a +pretty pretty broad spectrum I like that + + align:start position:0% +pretty pretty broad spectrum I like that + + + align:start position:0% +pretty pretty broad spectrum I like that +it's always good um who who agrees with + + align:start position:0% +it's always good um who who agrees with + + + align:start position:0% +it's always good um who who agrees with +greater than or equal to one note or or + + align:start position:0% +greater than or equal to one note or or + + + align:start position:0% +greater than or equal to one note or or +wants more disagree if you want more + + align:start position:0% +wants more disagree if you want more + + + align:start position:0% +wants more disagree if you want more +specificity than that who agrees with + + align:start position:0% +specificity than that who agrees with + + + align:start position:0% +specificity than that who agrees with +greater than or equal to one note good + + align:start position:0% +greater than or equal to one note good + + + align:start position:0% +greater than or equal to one note good +Jordan's on your side and you just got + + align:start position:0% +Jordan's on your side and you just got + + + align:start position:0% +Jordan's on your side and you just got +some some people good so who disagrees + + align:start position:0% +some some people good so who disagrees + + + align:start position:0% +some some people good so who disagrees +with that with everything beforehand up + + align:start position:0% +with that with everything beforehand up + + + align:start position:0% +with that with everything beforehand up +till now great so um I think we have um + + align:start position:0% +till now great so um I think we have um + + + align:start position:0% +till now great so um I think we have um +no Jason we've already gone through who + + align:start position:0% +no Jason we've already gone through who + + + align:start position:0% +no Jason we've already gone through who +who raise your hands again if you + + align:start position:0% +who raise your hands again if you + + + align:start position:0% +who raise your hands again if you +disagree I want to keep going + + align:start position:0% +disagree I want to keep going + + + align:start position:0% +disagree I want to keep going +alphabetically next among the disagreer + + align:start position:0% +alphabetically next among the disagreer + + + align:start position:0% +alphabetically next among the disagreer +and that would that might be uh Kara + + align:start position:0% +and that would that might be uh Kara + + + align:start position:0% +and that would that might be uh Kara +Karima yeah yeah uh I I wrote na na okay + + align:start position:0% +Karima yeah yeah uh I I wrote na na okay + + + align:start position:0% +Karima yeah yeah uh I I wrote na na okay +well well na a or we we'll we'll make it + + align:start position:0% +well well na a or we we'll we'll make it + + + align:start position:0% +well well na a or we we'll we'll make it +so it parses in Python not a number is + + align:start position:0% +so it parses in Python not a number is + + + align:start position:0% +so it parses in Python not a number is +that okay okay good good and any um + + align:start position:0% +that okay okay good good and any um + + + align:start position:0% +that okay okay good good and any um +anybody still still have your number not + + align:start position:0% +anybody still still have your number not + + + align:start position:0% +anybody still still have your number not +said Adam yeah I said 14 or 15 14 or 15 + + align:start position:0% +said Adam yeah I said 14 or 15 14 or 15 + + + align:start position:0% +said Adam yeah I said 14 or 15 14 or 15 +okay very very specific um what did you + + align:start position:0% +okay very very specific um what did you + + + align:start position:0% +okay very very specific um what did you +base that on so you went from a c to + + align:start position:0% +base that on so you went from a c to + + + align:start position:0% +base that on so you went from a c to +either a c or a d so it's like if you go + + align:start position:0% +either a c or a d so it's like if you go + + + align:start position:0% +either a c or a d so it's like if you go +all the chromatic notes and slur them + + align:start position:0% +all the chromatic notes and slur them + + + align:start position:0% +all the chromatic notes and slur them +all that's what you get okay okay good + + align:start position:0% +all that's what you get okay okay good + + + align:start position:0% +all that's what you get okay okay good +so we have we have a range extension um + + align:start position:0% +so we have we have a range extension um + + + align:start position:0% +so we have we have a range extension um +good uh anybody else have a number that + + align:start position:0% +good uh anybody else have a number that + + + align:start position:0% +good uh anybody else have a number that +doesn't hasn't been done + + align:start position:0% +doesn't hasn't been done + + + align:start position:0% +doesn't hasn't been done +yet okay um so that's that's + + align:start position:0% +yet okay um so that's that's + + + align:start position:0% +yet okay um so that's that's +particularly good um this one I went + + align:start position:0% +particularly good um this one I went + + + align:start position:0% +particularly good um this one I went +with INF oh sorry I wasn't telling you + + align:start position:0% +with INF oh sorry I wasn't telling you + + + align:start position:0% +with INF oh sorry I wasn't telling you +what what my numbers were yet okay well + + align:start position:0% +what what my numbers were yet okay well + + + align:start position:0% +what what my numbers were yet okay well +that one that's what I went with um and + + align:start position:0% +that one that's what I went with um and + + + align:start position:0% +that one that's what I went with um and +then uh next one D + + align:start position:0% + + + + align:start position:0% + +um we have + + align:start position:0% +um we have + + + align:start position:0% +um we have +some you want we have a a listener but + + align:start position:0% +some you want we have a a listener but + + + align:start position:0% +some you want we have a a listener but +you want to be a participant or also + + align:start position:0% +you want to be a participant or also + + + align:start position:0% +you want to be a participant or also +yeah go ahead so with that one I wrote + + align:start position:0% +yeah go ahead so with that one I wrote + + + align:start position:0% +yeah go ahead so with that one I wrote +six + + align:start position:0% +six + + + align:start position:0% +six +six anybody agree yep anybody + + align:start position:0% +six anybody agree yep anybody + + + align:start position:0% +six anybody agree yep anybody +disagree good + + align:start position:0% +disagree good + + + align:start position:0% +disagree good +okay and + + align:start position:0% +okay and + + + align:start position:0% +okay and +um yep and now oh no I was giving I was + + align:start position:0% +um yep and now oh no I was giving I was + + + align:start position:0% +um yep and now oh no I was giving I was +giving the right numbers yep so I'm + + align:start position:0% +giving the right numbers yep so I'm + + + align:start position:0% +giving the right numbers yep so I'm +going to say I did that I did that uh + + align:start position:0% +going to say I did that I did that uh + + + align:start position:0% +going to say I did that I did that uh +nobody disagreed the correct answer + + align:start position:0% +nobody disagreed the correct answer + + + align:start position:0% +nobody disagreed the correct answer +there was + + align:start position:0% +there was + + + align:start position:0% +there was +two and don't worry don't worry this is + + align:start position:0% +two and don't worry don't worry this is + + + align:start position:0% +two and don't worry don't worry this is +frustrating be frustrating and + + align:start position:0% +frustrating be frustrating and + + + align:start position:0% +frustrating be frustrating and +then uh who's also around K or do I hear + + align:start position:0% +then uh who's also around K or do I hear + + + align:start position:0% +then uh who's also around K or do I hear +l + + align:start position:0% +l + + + align:start position:0% +l +l + + align:start position:0% + + + + align:start position:0% + +zero anybody + + align:start position:0% +zero anybody + + + align:start position:0% +zero anybody +disagree great uh uh person who's + + align:start position:0% +disagree great uh uh person who's + + + align:start position:0% +disagree great uh uh person who's +disagreed who has to speak um I just + + align:start position:0% +disagreed who has to speak um I just + + + align:start position:0% +disagreed who has to speak um I just +said one one good good who agrees with + + align:start position:0% +said one one good good who agrees with + + + align:start position:0% +said one one good good who agrees with +one good how many people have heard + + align:start position:0% +one good how many people have heard + + + align:start position:0% +one good how many people have heard +neither zero nor + + align:start position:0% +neither zero nor + + + align:start position:0% +neither zero nor +one y so when I was not writing a lot of + + align:start position:0% +one y so when I was not writing a lot of + + + align:start position:0% +one y so when I was not writing a lot of +these I put two answers to a lot of them + + align:start position:0% +these I put two answers to a lot of them + + + align:start position:0% +these I put two answers to a lot of them +depending on okay but you can only give + + align:start position:0% +depending on okay but you can only give + + + align:start position:0% +depending on okay but you can only give +one right now well I was how I not how + + align:start position:0% +one right now well I was how I not how + + + align:start position:0% +one right now well I was how I not how +i' like pitch wise and I was I was + + align:start position:0% +i' like pitch wise and I was I was + + + align:start position:0% +i' like pitch wise and I was I was +taking I I was taking perception + + align:start position:0% +taking I I was taking perception + + + align:start position:0% +taking I I was taking perception +spectrograms and a clap has like all of + + align:start position:0% +spectrograms and a clap has like all of + + + align:start position:0% +spectrograms and a clap has like all of +the + + align:start position:0% +the + + + align:start position:0% +the +so so so give me a number so that one + + align:start position:0% +so so so give me a number so that one + + + align:start position:0% +so so so give me a number so that one +would also be INF INF okay + + align:start position:0% +would also be INF INF okay + + + align:start position:0% +would also be INF INF okay +good this one I'm going to go with + + align:start position:0% +good this one I'm going to go with + + + align:start position:0% +good this one I'm going to go with +zero and I will tell you um there isn't + + align:start position:0% +zero and I will tell you um there isn't + + + align:start position:0% +zero and I will tell you um there isn't +a single answer on here that I couldn't + + align:start position:0% +a single answer on here that I couldn't + + + align:start position:0% +a single answer on here that I couldn't +that you couldn't argue for and be + + align:start position:0% +that you couldn't argue for and be + + + align:start position:0% +that you couldn't argue for and be +correct so um why three notes I think we + + align:start position:0% +correct so um why three notes I think we + + + align:start position:0% +correct so um why three notes I think we +all agreed because I think I saying bom + + align:start position:0% +all agreed because I think I saying bom + + + align:start position:0% +all agreed because I think I saying bom +bom bom I count each of those as one + + align:start position:0% +bom bom I count each of those as one + + + align:start position:0% +bom bom I count each of those as one +note right second one was four + + align:start position:0% + + + + align:start position:0% + +cuz was a half a whole note tied to a + + align:start position:0% +cuz was a half a whole note tied to a + + + align:start position:0% +cuz was a half a whole note tied to a +quarter note tied to uh a 60th note tied + + align:start position:0% +quarter note tied to uh a 60th note tied + + + align:start position:0% +quarter note tied to uh a 60th note tied +to a 64th + + align:start position:0% +to a 64th + + + align:start position:0% +to a 64th +note and I do believe that is the + + align:start position:0% +note and I do believe that is the + + + align:start position:0% +note and I do believe that is the +closest shortest representation I can do + + align:start position:0% +closest shortest representation I can do + + + align:start position:0% +closest shortest representation I can do +notationally so I was thinking in a + + align:start position:0% +notationally so I was thinking in a + + + align:start position:0% +notationally so I was thinking in a +notational sphere + + align:start position:0% +notational sphere + + + align:start position:0% +notational sphere +here this time with the gando I was + + align:start position:0% +here this time with the gando I was + + + align:start position:0% +here this time with the gando I was +thinking of it as an infinite number of + + align:start position:0% +thinking of it as an infinite number of + + + align:start position:0% +thinking of it as an infinite number of +notes because if it's continuous it + + align:start position:0% +notes because if it's continuous it + + + align:start position:0% +notes because if it's continuous it +could be but on the other hand it any of + + align:start position:0% +could be but on the other hand it any of + + + align:start position:0% +could be but on the other hand it any of +these other ones could be correct now + + align:start position:0% +these other ones could be correct now + + + align:start position:0% +these other ones could be correct now +let's see if anyone can come up with how + + align:start position:0% +let's see if anyone can come up with how + + + align:start position:0% +let's see if anyone can come up with how +from + + align:start position:0% +from + + + align:start position:0% +from +D I came up with + + align:start position:0% +D I came up with + + + align:start position:0% +D I came up with +two the two different pitches that's one + + align:start position:0% +two the two different pitches that's one + + + align:start position:0% +two the two different pitches that's one +good way to do it um I'm glad I I hit + + align:start position:0% +good way to do it um I'm glad I I hit + + + align:start position:0% +good way to do it um I'm glad I I hit +the same pitch each time maybe I'm close + + align:start position:0% +the same pitch each time maybe I'm close + + + align:start position:0% +the same pitch each time maybe I'm close +um that's not the reason why I was + + align:start position:0% +um that's not the reason why I was + + + align:start position:0% +um that's not the reason why I was +thinking yeah it's like the trol trevolo + + align:start position:0% +thinking yeah it's like the trol trevolo + + + align:start position:0% +thinking yeah it's like the trol trevolo +yeah it was something like I know well + + align:start position:0% +yeah it was something like I know well + + + align:start position:0% +yeah it was something like I know well +don't know what thing we're in but yeah + + align:start position:0% +don't know what thing we're in but yeah + + + align:start position:0% +don't know what thing we're in but yeah +I was thinking it has something like + + align:start position:0% +I was thinking it has something like + + + align:start position:0% +I was thinking it has something like +that or actually would be measured + + align:start position:0% +that or actually would be measured + + + align:start position:0% +that or actually would be measured +tremolo wouldn't it be + + align:start position:0% + + + + align:start position:0% + +like anyone know this sign where you + + align:start position:0% +like anyone know this sign where you + + + align:start position:0% +like anyone know this sign where you +have a beamed or no just one beam right + + align:start position:0% +have a beamed or no just one beam right + + + align:start position:0% +have a beamed or no just one beam right +two beamed dotted half notes you see it + + align:start position:0% +two beamed dotted half notes you see it + + + align:start position:0% +two beamed dotted half notes you see it +everywhere every once a while when + + align:start position:0% +everywhere every once a while when + + + align:start position:0% +everywhere every once a while when +you're playing like POF off or or uh or + + align:start position:0% +you're playing like POF off or or uh or + + + align:start position:0% +you're playing like POF off or or uh or +shert and stuff and I always like oh I + + align:start position:0% +shert and stuff and I always like oh I + + + align:start position:0% +shert and stuff and I always like oh I +have to remember what that is but that + + align:start position:0% +have to remember what that is but that + + + align:start position:0% +have to remember what that is but that +means fill in the space of one dotted + + align:start position:0% +means fill in the space of one dotted + + + align:start position:0% +means fill in the space of one dotted +half note with as many eighth notes as + + align:start position:0% +half note with as many eighth notes as + + + align:start position:0% +half note with as many eighth notes as +it takes to fill it in alternating + + align:start position:0% +it takes to fill it in alternating + + + align:start position:0% +it takes to fill it in alternating +between the top one and the bottom + + align:start position:0% + + + + align:start position:0% + +one and + + align:start position:0% +one and + + + align:start position:0% +one and +clap I thought a note to me had to have + + align:start position:0% +clap I thought a note to me had to have + + + align:start position:0% +clap I thought a note to me had to have +some sort of specifiable + + align:start position:0% +some sort of specifiable + + + align:start position:0% +some sort of specifiable +pitch so I count zero + + align:start position:0% +pitch so I count zero + + + align:start position:0% +pitch so I count zero +now everything that somebody said uh one + + align:start position:0% +now everything that somebody said uh one + + + align:start position:0% +now everything that somebody said uh one +for for this or infinite are all valid + + align:start position:0% +for for this or infinite are all valid + + + align:start position:0% +for for this or infinite are all valid +definitions of what we're going to be + + align:start position:0% +definitions of what we're going to be + + + align:start position:0% +definitions of what we're going to be +talking + + align:start position:0% +talking + + + align:start position:0% +talking +about and here's the thing 99% of the + + align:start position:0% +about and here's the thing 99% of the + + + align:start position:0% +about and here's the thing 99% of the +time when I'm not trying to set up an + + align:start position:0% +time when I'm not trying to set up an + + + align:start position:0% +time when I'm not trying to set up an +example for um you know for kind having + + align:start position:0% +example for um you know for kind having + + + align:start position:0% +example for um you know for kind having +fun in the first week of class with you + + align:start position:0% +fun in the first week of class with you + + + align:start position:0% +fun in the first week of class with you +all uh there's no way I would call that + + align:start position:0% +all uh there's no way I would call that + + + align:start position:0% +all uh there's no way I would call that +second one four notes right I mean if I + + align:start position:0% +second one four notes right I mean if I + + + align:start position:0% +second one four notes right I mean if I +hear it I'm going to be one + + align:start position:0% +hear it I'm going to be one + + + align:start position:0% +hear it I'm going to be one +so one of the things that's going to + + align:start position:0% +so one of the things that's going to + + + align:start position:0% +so one of the things that's going to +come up quite often is that depending on + + align:start position:0% +come up quite often is that depending on + + + align:start position:0% +come up quite often is that depending on +what purpose you want to do with + + align:start position:0% +what purpose you want to do with + + + align:start position:0% +what purpose you want to do with +something you're not going to be able to + + align:start position:0% +something you're not going to be able to + + + align:start position:0% +something you're not going to be able to +um necessarily even know how many notes + + align:start position:0% +um necessarily even know how many notes + + + align:start position:0% +um necessarily even know how many notes +or how many of something there is let + + align:start position:0% +or how many of something there is let + + + align:start position:0% +or how many of something there is let +alone what's the correct spelling of + + align:start position:0% +alone what's the correct spelling of + + + align:start position:0% +alone what's the correct spelling of +something or not + + align:start position:0% +something or not + + + align:start position:0% +something or not +um so I think we're just going to be + + align:start position:0% +um so I think we're just going to be + + + align:start position:0% +um so I think we're just going to be +playing around with something like this + + align:start position:0% +playing around with something like this + + + align:start position:0% +playing around with something like this +now go back to your definitions of notes + + align:start position:0% +now go back to your definitions of notes + + + align:start position:0% +now go back to your definitions of notes +that you had before and let's grab into + + align:start position:0% +that you had before and let's grab into + + + align:start position:0% +that you had before and let's grab into +groups of four so your two groups that + + align:start position:0% +groups of four so your two groups that + + + align:start position:0% +groups of four so your two groups that +are the same joining with a group behind + + align:start position:0% +are the same joining with a group behind + + + align:start position:0% +are the same joining with a group behind +you so that's we're going to get good + + align:start position:0% +you so that's we're going to get good + + + align:start position:0% +you so that's we're going to get good +spinning over here we'll create a group + + align:start position:0% +spinning over here we'll create a group + + + align:start position:0% +spinning over here we'll create a group +of three here and three here and we'll + + align:start position:0% +of three here and three here and we'll + + + align:start position:0% +of three here and three here and we'll +we'll break up uh this this group and + + align:start position:0% +we'll break up uh this this group and + + + align:start position:0% +we'll break up uh this this group and +talk about what your definitions of the + + align:start position:0% +talk about what your definitions of the + + + align:start position:0% +talk about what your definitions of the +notes were with the other group and then + + align:start position:0% +notes were with the other group and then + + + align:start position:0% +notes were with the other group and then +try to figure out a if you had correct + + align:start position:0% +try to figure out a if you had correct + + + align:start position:0% +try to figure out a if you had correct +definitions or if you had compatible not + + align:start position:0% +definitions or if you had compatible not + + + align:start position:0% +definitions or if you had compatible not +a correct definition compatible + + align:start position:0% +a correct definition compatible + + + align:start position:0% +a correct definition compatible +definitions of notes before that with + + align:start position:0% +definitions of notes before that with + + + align:start position:0% +definitions of notes before that with +each other's group and then also if you + + align:start position:0% +each other's group and then also if you + + + align:start position:0% +each other's group and then also if you +want to change definition based on all + + align:start position:0% +want to change definition based on all + + + align:start position:0% +want to change definition based on all +the weird numbers that we came up with + + align:start position:0% +the weird numbers that we came up with + + + align:start position:0% +the weird numbers that we came up with +here so go ahead and let's take a couple + + align:start position:0% +here so go ahead and let's take a couple + + + align:start position:0% +here so go ahead and let's take a couple +minutes to do that great let's let's all + + align:start position:0% +minutes to do that great let's let's all + + + align:start position:0% +minutes to do that great let's let's all +come back together + + align:start position:0% + + + + align:start position:0% + +and + + align:start position:0% + + + + align:start position:0% + +um there was one word that I just kept + + align:start position:0% +um there was one word that I just kept + + + align:start position:0% +um there was one word that I just kept +hearing as I was going around and it + + align:start position:0% +hearing as I was going around and it + + + align:start position:0% +hearing as I was going around and it +begins like this I want any any group + + align:start position:0% +begins like this I want any any group + + + align:start position:0% +begins like this I want any any group +use a word that begins with this in + + align:start position:0% +use a word that begins with this in + + + align:start position:0% +use a word that begins with this in +their + + align:start position:0% +their + + + align:start position:0% +their +definition yeah John go ahead + + align:start position:0% +definition yeah John go ahead + + + align:start position:0% +definition yeah John go ahead +representation representation + + align:start position:0% + + + + align:start position:0% + +yeah so we can kind of start with + + align:start position:0% +yeah so we can kind of start with + + + align:start position:0% +yeah so we can kind of start with +a is + + align:start position:0% +a is + + + align:start position:0% +a is +uh of + + align:start position:0% +uh of + + + align:start position:0% +uh of +is any anybody's definition um + + align:start position:0% +is any anybody's definition um + + + align:start position:0% +is any anybody's definition um +completely incompatible with this + + align:start position:0% +completely incompatible with this + + + align:start position:0% +completely incompatible with this +opening like couldn't be put in is no + + align:start position:0% +opening like couldn't be put in is no + + + align:start position:0% +opening like couldn't be put in is no +smile of thing okay so what are some of + + align:start position:0% +smile of thing okay so what are some of + + + align:start position:0% +smile of thing okay so what are some of +the ways that your groups could have um + + align:start position:0% +the ways that your groups could have um + + + align:start position:0% +the ways that your groups could have um +could have uh done this I didn't think I + + align:start position:0% +could have uh done this I didn't think I + + + align:start position:0% +could have uh done this I didn't think I +heard um because it's physically + + align:start position:0% +heard um because it's physically + + + align:start position:0% +heard um because it's physically +difficult what uh Jonathan Kara Jordan + + align:start position:0% +difficult what uh Jonathan Kara Jordan + + + align:start position:0% +difficult what uh Jonathan Kara Jordan +and Misha's group um came up with what + + align:start position:0% +and Misha's group um came up with what + + + align:start position:0% +and Misha's group um came up with what +do you How would how would somebody in + + align:start position:0% +do you How would how would somebody in + + + align:start position:0% +do you How would how would somebody in +this group uh continue that uh everybody + + align:start position:0% +this group uh continue that uh everybody + + + align:start position:0% +this group uh continue that uh everybody +has oh you guys are all normally + + align:start position:0% +has oh you guys are all normally + + + align:start position:0% +has oh you guys are all normally +distributed names so I've heard from + + align:start position:0% +distributed names so I've heard from + + + align:start position:0% +distributed names so I've heard from +everybody so um would you like + + align:start position:0% +everybody so um would you like + + + align:start position:0% +everybody so um would you like +to is a representation of + + align:start position:0% + + + + align:start position:0% + +anything with a + + align:start position:0% +anything with a + + + align:start position:0% +anything with a +pitch and + + align:start position:0% + + + + align:start position:0% + +duration I groups disagree with that + + align:start position:0% + + + + align:start position:0% + +yeah so I'm coming at this from the + + align:start position:0% +yeah so I'm coming at this from the + + + align:start position:0% +yeah so I'm coming at this from the +percussion perspective where a note + + align:start position:0% +percussion perspective where a note + + + align:start position:0% +percussion perspective where a note +doesn't necessarily need a pitch and it + + align:start position:0% +doesn't necessarily need a pitch and it + + + align:start position:0% +doesn't necessarily need a pitch and it +doesn't necessarily need a duration okay + + align:start position:0% +doesn't necessarily need a duration okay + + + align:start position:0% +doesn't necessarily need a duration okay +so so we have um not necessarily on that + + align:start position:0% +so so we have um not necessarily on that + + + align:start position:0% +so so we have um not necessarily on that +so do you have a positive did your group + + align:start position:0% +so do you have a positive did your group + + + align:start position:0% +so do you have a positive did your group +come up with a positive + + align:start position:0% +come up with a positive + + + align:start position:0% +come up with a positive +um uh definition from that I don't think + + align:start position:0% +um uh definition from that I don't think + + + align:start position:0% +um uh definition from that I don't think +our group came into agreement good let's + + align:start position:0% +our group came into agreement good let's + + + align:start position:0% +our group came into agreement good let's +hear something is a note as a + + align:start position:0% +hear something is a note as a + + + align:start position:0% +hear something is a note as a +representation of an instance of stri in + + align:start position:0% +representation of an instance of stri in + + + align:start position:0% +representation of an instance of stri in +something an instance of striking + + align:start position:0% +something an instance of striking + + + align:start position:0% +something an instance of striking +something okay anybody + + align:start position:0% + + + + align:start position:0% + +um so it's Matthew anybody um want + + align:start position:0% +um so it's Matthew anybody um want + + + align:start position:0% +um so it's Matthew anybody um want +to want to um go + + align:start position:0% +to want to um go + + + align:start position:0% +to want to um go +forward with that like sorry I can't + + align:start position:0% +forward with that like sorry I can't + + + align:start position:0% +forward with that like sorry I can't +talk and write something else at the + + align:start position:0% +talk and write something else at the + + + align:start position:0% +talk and write something else at the +same + + align:start position:0% +same + + + align:start position:0% +same +time + + align:start position:0% +time + + + align:start position:0% +time +anybody's that's um perfect to for out + + align:start position:0% +anybody's that's um perfect to for out + + + align:start position:0% +anybody's that's um perfect to for out +things while you're speaking uh anything + + align:start position:0% +things while you're speaking uh anything + + + align:start position:0% +things while you're speaking uh anything +with a pitch and a duration I think an + + align:start position:0% +with a pitch and a duration I think an + + + align:start position:0% +with a pitch and a duration I think an +airplane on a airline flight has its + + align:start position:0% +airplane on a airline flight has its + + + align:start position:0% +airplane on a airline flight has its +pitch and duration right so we I'll + + align:start position:0% +pitch and duration right so we I'll + + + align:start position:0% +pitch and duration right so we I'll +start calling them Notes too no I'm just + + align:start position:0% +start calling them Notes too no I'm just + + + align:start position:0% +start calling them Notes too no I'm just +just having fun just trying to just + + align:start position:0% +just having fun just trying to just + + + align:start position:0% +just having fun just trying to just +trying to get us to think so we can + + align:start position:0% +trying to get us to think so we can + + + align:start position:0% +trying to get us to think so we can +start making things how we're going to + + align:start position:0% +start making things how we're going to + + + align:start position:0% +start making things how we're going to +make this happen for a computer I I like + + align:start position:0% +make this happen for a computer I I like + + + align:start position:0% +make this happen for a computer I I like +both of these an instance of striking + + align:start position:0% +both of these an instance of striking + + + align:start position:0% +both of these an instance of striking +something so yeah I feel like that + + align:start position:0% +something so yeah I feel like that + + + align:start position:0% +something so yeah I feel like that +doesn't really apply to certain + + align:start position:0% +doesn't really apply to certain + + + align:start position:0% +doesn't really apply to certain +instruments like violence for example + + align:start position:0% +instruments like violence for example + + + align:start position:0% +instruments like violence for example +you don't have to anything to issue next + + align:start position:0% +you don't have to anything to issue next + + + align:start position:0% +you don't have to anything to issue next +not + + align:start position:0% +not + + + align:start position:0% +not +good so it's somebody who hasn't spoken + + align:start position:0% +good so it's somebody who hasn't spoken + + + align:start position:0% +good so it's somebody who hasn't spoken +want to defend an instance of striking + + align:start position:0% +want to defend an instance of striking + + + align:start position:0% +want to defend an instance of striking +something as applying to the + + align:start position:0% +something as applying to the + + + align:start position:0% +something as applying to the +violin yeah go ahead Vanessa so I mean + + align:start position:0% +violin yeah go ahead Vanessa so I mean + + + align:start position:0% +violin yeah go ahead Vanessa so I mean +if you want to be annoying you can use + + align:start position:0% +if you want to be annoying you can use + + + align:start position:0% +if you want to be annoying you can use +like a version of striking in a much + + align:start position:0% +like a version of striking in a much + + + align:start position:0% +like a version of striking in a much +more General sense necessarily be like + + align:start position:0% +more General sense necessarily be like + + + align:start position:0% +more General sense necessarily be like +hitting anything just be when you're + + align:start position:0% +hitting anything just be when you're + + + align:start position:0% +hitting anything just be when you're +moving a bow across strings you can say + + align:start position:0% +moving a bow across strings you can say + + + align:start position:0% +moving a bow across strings you can say +that that counts as like a form of + + align:start position:0% +that that counts as like a form of + + + align:start position:0% +that that counts as like a form of +striking even if it's not like the most + + align:start position:0% +striking even if it's not like the most + + + align:start position:0% +striking even if it's not like the most +straightforward definition okay about a + + align:start position:0% +straightforward definition okay about a + + + align:start position:0% +straightforward definition okay about a +wind + + align:start position:0% + + + + align:start position:0% + +instrument + + align:start position:0% +instrument + + + align:start position:0% +instrument +okay who's you y all most of you are are + + align:start position:0% +okay who's you y all most of you are are + + + align:start position:0% +okay who's you y all most of you are are +Juniors and seniors and things so y all + + align:start position:0% +Juniors and seniors and things so y all + + + align:start position:0% +Juniors and seniors and things so y all +most of you all have gotten through your + + align:start position:0% +most of you all have gotten through your + + + align:start position:0% +most of you all have gotten through your +um physics mechanics uh General + + align:start position:0% +um physics mechanics uh General + + + align:start position:0% +um physics mechanics uh General +Institute requirement anybody want to + + align:start position:0% +Institute requirement anybody want to + + + align:start position:0% +Institute requirement anybody want to +say how do what's how's sound + + align:start position:0% + + + + align:start position:0% + +produced or perceived maybe moving + + align:start position:0% +produced or perceived maybe moving + + + align:start position:0% +produced or perceived maybe moving +vibrations of air vibrations of air good + + align:start position:0% +vibrations of air vibrations of air good + + + align:start position:0% +vibrations of air vibrations of air good +and and so there's a lot of air + + align:start position:0% +and and so there's a lot of air + + + align:start position:0% +and and so there's a lot of air +vibrating way way down the street why + + align:start position:0% +vibrating way way down the street why + + + align:start position:0% +vibrating way way down the street why +why do I not hear + + align:start position:0% +why do I not hear + + + align:start position:0% +why do I not hear +it the inverse Square law yes that might + + align:start position:0% +it the inverse Square law yes that might + + + align:start position:0% +it the inverse Square law yes that might +that might be but what what is not + + align:start position:0% +that might be but what what is not + + + align:start position:0% +that might be but what what is not +happening with the movement of air it's + + align:start position:0% +happening with the movement of air it's + + + align:start position:0% +happening with the movement of air it's +not reaching our ears it's not reaching + + align:start position:0% +not reaching our ears it's not reaching + + + align:start position:0% +not reaching our ears it's not reaching +our ears it's + + align:start position:0% +our ears it's + + + align:start position:0% +our ears it's +not what what what is the what is one of + + align:start position:0% +not what what what is the what is one of + + + align:start position:0% +not what what what is the what is one of +the first thing it reaches in our ears e + + align:start position:0% +the first thing it reaches in our ears e + + + align:start position:0% +the first thing it reaches in our ears e +drum ear drum oh so maybe there is a way + + align:start position:0% +drum ear drum oh so maybe there is a way + + + align:start position:0% +drum ear drum oh so maybe there is a way +so we could say an instance of something + + align:start position:0% +so we could say an instance of something + + + align:start position:0% +so we could say an instance of something +striking something um such as air + + align:start position:0% +striking something um such as air + + + align:start position:0% +striking something um such as air +striking a + + align:start position:0% + + + + align:start position:0% + +drum + + align:start position:0% +drum + + + align:start position:0% +drum +before half an hour of you ago how many + + align:start position:0% +before half an hour of you ago how many + + + align:start position:0% +before half an hour of you ago how many +of you would have said that that's a + + align:start position:0% +of you would have said that that's a + + + align:start position:0% +of you would have said that that's a +note + + align:start position:0% + + + + align:start position:0% + +what's it + + align:start position:0% + + + + align:start position:0% + +striking it doesn't need a strike you + + align:start position:0% +striking it doesn't need a strike you + + + align:start position:0% +striking it doesn't need a strike you +said it's a representation of oh it's a + + align:start position:0% +said it's a representation of oh it's a + + + align:start position:0% +said it's a representation of oh it's a +representation of something striking + + align:start position:0% +representation of something striking + + + align:start position:0% +representation of something striking +good good okay any other things that we + + align:start position:0% +good good okay any other things that we + + + align:start position:0% +good good okay any other things that we +want to do with confusing confusing + + align:start position:0% +want to do with confusing confusing + + + align:start position:0% +want to do with confusing confusing +definitions before we get to the one of + + align:start position:0% +definitions before we get to the one of + + + align:start position:0% +definitions before we get to the one of +the points of this + + align:start position:0% +the points of this + + + align:start position:0% +the points of this +class any other really um great + + align:start position:0% +class any other really um great + + + align:start position:0% +class any other really um great +beautiful things that wasn't covered + + align:start position:0% +beautiful things that wasn't covered + + + align:start position:0% +beautiful things that wasn't covered +here + + align:start position:0% + + + + align:start position:0% + +by the way I I forgot to do this part on + + align:start position:0% +by the way I I forgot to do this part on + + + align:start position:0% +by the way I I forgot to do this part on +there + + align:start position:0% + + + + align:start position:0% + +um how many + + align:start position:0% + + + + align:start position:0% + +notes okay so if there's something when + + align:start position:0% +notes okay so if there's something when + + + align:start position:0% +notes okay so if there's something when +you play that the three different sounds + + align:start position:0% +you play that the three different sounds + + + align:start position:0% +you play that the three different sounds +being done could be considered three + + align:start position:0% +being done could be considered three + + + align:start position:0% +being done could be considered three +different notes so is a chord a note or + + align:start position:0% +different notes so is a chord a note or + + + align:start position:0% +different notes so is a chord a note or +is a chord a bunch of notes not or is a + + align:start position:0% +is a chord a bunch of notes not or is a + + + align:start position:0% +is a chord a bunch of notes not or is a +chord something + + align:start position:0% + + + + align:start position:0% + +else I'd say this because we're going to + + align:start position:0% +else I'd say this because we're going to + + + align:start position:0% +else I'd say this because we're going to +spend the a lot of the first problem set + + align:start position:0% +spend the a lot of the first problem set + + + align:start position:0% +spend the a lot of the first problem set +in the next week is going to be on how + + align:start position:0% +in the next week is going to be on how + + + align:start position:0% +in the next week is going to be on how +to represent music for the computers for + + align:start position:0% +to represent music for the computers for + + + align:start position:0% +to represent music for the computers for +the computers as as + + align:start position:0% +the computers as as + + + align:start position:0% +the computers as as +1960s for a computer so how do we um how + + align:start position:0% +1960s for a computer so how do we um how + + + align:start position:0% +1960s for a computer so how do we um how +do what kinds of choices will lead us + + align:start position:0% +do what kinds of choices will lead us + + + align:start position:0% +do what kinds of choices will lead us +into bad places fastest and which Ones + + align:start position:0% +into bad places fastest and which Ones + + + align:start position:0% +into bad places fastest and which Ones +Will Keep Us in good and useful places + + align:start position:0% +Will Keep Us in good and useful places + + + align:start position:0% +Will Keep Us in good and useful places +for the longest amount of time notice I + + align:start position:0% +for the longest amount of time notice I + + + align:start position:0% +for the longest amount of time notice I +didn't say which ones will never lead + + align:start position:0% +didn't say which ones will never lead + + + align:start position:0% +didn't say which ones will never lead +you astray because you're always every + + align:start position:0% +you astray because you're always every + + + align:start position:0% +you astray because you're always every +definition that you're going to encode + + align:start position:0% +definition that you're going to encode + + + align:start position:0% +definition that you're going to encode +into a computer at some point is going + + align:start position:0% +into a computer at some point is going + + + align:start position:0% +into a computer at some point is going +to completely screw up something for + + align:start position:0% +to completely screw up something for + + + align:start position:0% +to completely screw up something for +instance + + align:start position:0% +instance + + + align:start position:0% +instance +um we might say one + + align:start position:0% +um we might say one + + + align:start position:0% +um we might say one +note add a little ornament to + + align:start position:0% +note add a little ornament to + + + align:start position:0% +note add a little ornament to +it still one note in some certain senses + + align:start position:0% +it still one note in some certain senses + + + align:start position:0% +it still one note in some certain senses +but y that kind of turn can really + + align:start position:0% +but y that kind of turn can really + + + align:start position:0% +but y that kind of turn can really +change everything so those are going to + + align:start position:0% +change everything so those are going to + + + align:start position:0% +change everything so those are going to +be coming up over and over and over + + align:start position:0% +be coming up over and over and over + + + align:start position:0% +be coming up over and over and over +again how to represent for a computer + + align:start position:0% +again how to represent for a computer + + + align:start position:0% +again how to represent for a computer +and whether or not any one + + align:start position:0% +and whether or not any one + + + align:start position:0% +and whether or not any one +representation is going to work um + + align:start position:0% +representation is going to work um + + + align:start position:0% +representation is going to work um +somebody said a note is a representation + + align:start position:0% +somebody said a note is a representation + + + align:start position:0% +somebody said a note is a representation +of anything with a pitch and a + + align:start position:0% +of anything with a pitch and a + + + align:start position:0% +of anything with a pitch and a +duration um there are some people who + + align:start position:0% +duration um there are some people who + + + align:start position:0% +duration um there are some people who +use the term note and the term pitch + + align:start position:0% +use the term note and the term pitch + + + align:start position:0% +use the term note and the term pitch +absolutely interchangeably + + align:start position:0% +absolutely interchangeably + + + align:start position:0% +absolutely interchangeably +and I do it sometimes also you what + + align:start position:0% +and I do it sometimes also you what + + + align:start position:0% +and I do it sometimes also you what +pitch was that what note what note did + + align:start position:0% +pitch was that what note what note did + + + align:start position:0% +pitch was that what note what note did +you play um things and other people use + + align:start position:0% +you play um things and other people use + + + align:start position:0% +you play um things and other people use +a note to mean the pitch and the + + align:start position:0% +a note to mean the pitch and the + + + align:start position:0% +a note to mean the pitch and the +duration as two different + + align:start position:0% +duration as two different + + + align:start position:0% +duration as two different +entities now + + align:start position:0% +entities now + + + align:start position:0% +entities now +obviously that also leads to certain + + align:start position:0% +obviously that also leads to certain + + + align:start position:0% +obviously that also leads to certain +contradictions I would hope that we + + align:start position:0% +contradictions I would hope that we + + + align:start position:0% +contradictions I would hope that we +think that an eighth note is a + + align:start position:0% +think that an eighth note is a + + + align:start position:0% +think that an eighth note is a +note right I mean it has the word note + + align:start position:0% +note right I mean it has the word note + + + align:start position:0% +note right I mean it has the word note +in its name we're not we're not talking + + align:start position:0% +in its name we're not we're not talking + + + align:start position:0% +in its name we're not we're not talking +about uh Quavers in in Britain I mean at + + align:start position:0% +about uh Quavers in in Britain I mean at + + + align:start position:0% +about uh Quavers in in Britain I mean at +least here in good old us OFA we put the + + align:start position:0% +least here in good old us OFA we put the + + + align:start position:0% +least here in good old us OFA we put the +word note in our eighth notes but by + + align:start position:0% +word note in our eighth notes but by + + + align:start position:0% +word note in our eighth notes but by +this definition pitch and duration and + + align:start position:0% +this definition pitch and duration and + + + align:start position:0% +this definition pitch and duration and +eighth note itself is not a + + align:start position:0% +eighth note itself is not a + + + align:start position:0% +eighth note itself is not a +note because it doesn't have a pitch so + + align:start position:0% +note because it doesn't have a pitch so + + + align:start position:0% +note because it doesn't have a pitch so +we're going to be finding that we're + + align:start position:0% +we're going to be finding that we're + + + align:start position:0% +we're going to be finding that we're +going to going back and forth quite + + align:start position:0% +going to going back and forth quite + + + align:start position:0% +going to going back and forth quite +often now let's um your problem set is + + align:start position:0% +often now let's um your problem set is + + + align:start position:0% +often now let's um your problem set is +going to be dealing with certain + + align:start position:0% +going to be dealing with certain + + + align:start position:0% +going to be dealing with certain +representations of pitch at least the + + align:start position:0% +representations of pitch at least the + + + align:start position:0% +representations of pitch at least the +non duration part of something I I will + + align:start position:0% +non duration part of something I I will + + + align:start position:0% +non duration part of something I I will +say uh I some will pop ahead when when + + align:start position:0% +say uh I some will pop ahead when when + + + align:start position:0% +say uh I some will pop ahead when when +the um when the lecture is getting too + + align:start position:0% +the um when the lecture is getting too + + + align:start position:0% +the um when the lecture is getting too +cerebral and things like that um in + + align:start position:0% +cerebral and things like that um in + + + align:start position:0% +cerebral and things like that um in +music 21 the software we're going to be + + align:start position:0% +music 21 the software we're going to be + + + align:start position:0% +music 21 the software we're going to be +using quite often this is probably the + + align:start position:0% +using quite often this is probably the + + + align:start position:0% +using quite often this is probably the +best closest definition to how music 21 + + align:start position:0% +best closest definition to how music 21 + + + align:start position:0% +best closest definition to how music 21 +Associates um things it's something with + + align:start position:0% +Associates um things it's something with + + + align:start position:0% +Associates um things it's something with +a conceived of single pitch and it + + align:start position:0% +a conceived of single pitch and it + + + align:start position:0% +a conceived of single pitch and it +conceived of single + + align:start position:0% +conceived of single + + + align:start position:0% +conceived of single +duration and that might mean that + + align:start position:0% +duration and that might mean that + + + align:start position:0% +duration and that might mean that +something like this is conceived of as + + align:start position:0% +something like this is conceived of as + + + align:start position:0% +something like this is conceived of as +having a single pitch + + align:start position:0% + + + + align:start position:0% + +or this is conceived of as having a + + align:start position:0% +or this is conceived of as having a + + + align:start position:0% +or this is conceived of as having a +single pitch that's a Trill sign um but + + align:start position:0% +single pitch that's a Trill sign um but + + + align:start position:0% +single pitch that's a Trill sign um but +there are other times when we don't + + align:start position:0% +there are other times when we don't + + + align:start position:0% +there are other times when we don't +conceive of something as a single pitch + + align:start position:0% +conceive of something as a single pitch + + + align:start position:0% +conceive of something as a single pitch +um and duration so let's talk about + + align:start position:0% +um and duration so let's talk about + + + align:start position:0% +um and duration so let's talk about +representations of duration so we've + + align:start position:0% +representations of duration so we've + + + align:start position:0% +representations of duration so we've +gone from the trick questions and now um + + align:start position:0% +gone from the trick questions and now um + + + align:start position:0% +gone from the trick questions and now um +now I hope I haven't like uh ended your + + align:start position:0% +now I hope I haven't like uh ended your + + + align:start position:0% +now I hope I haven't like uh ended your +faith in humanity in the class now I + + align:start position:0% +faith in humanity in the class now I + + + align:start position:0% +faith in humanity in the class now I +want to go to some a little bit um more + + align:start position:0% +want to go to some a little bit um more + + + align:start position:0% +want to go to some a little bit um more +thinking about standard situations and + + align:start position:0% +thinking about standard situations and + + + align:start position:0% +thinking about standard situations and +not weird tremolos and gandos and all + + align:start position:0% +not weird tremolos and gandos and all + + + align:start position:0% +not weird tremolos and gandos and all +that stuff um want to think about how + + align:start position:0% +that stuff um want to think about how + + + align:start position:0% +that stuff um want to think about how +are some ways you might represent pitch + + align:start position:0% +are some ways you might represent pitch + + + align:start position:0% +are some ways you might represent pitch +uh duration for a + + align:start position:0% + + + + align:start position:0% + +computer and we'll + + align:start position:0% +computer and we'll + + + align:start position:0% +computer and we'll +say um + + align:start position:0% +say um + + + align:start position:0% +say um +I'm going to put the term here + + align:start position:0% +I'm going to put the term here + + + align:start position:0% +I'm going to put the term here +musical as if somehow there's a + + align:start position:0% +musical as if somehow there's a + + + align:start position:0% +musical as if somehow there's a +different world of time in music than + + align:start position:0% +different world of time in music than + + + align:start position:0% +different world of time in music than +there is in everywhere else it's sort of + + align:start position:0% +there is in everywhere else it's sort of + + + align:start position:0% +there is in everywhere else it's sort of +there's three kinds of time in the world + + align:start position:0% +there's three kinds of time in the world + + + align:start position:0% +there's three kinds of time in the world +there's one on your clock there's one on + + align:start position:0% +there's one on your clock there's one on + + + align:start position:0% +there's one on your clock there's one on +music and there's the one they teach you + + align:start position:0% +music and there's the one they teach you + + + align:start position:0% +music and there's the one they teach you +about in relativity class that you hope + + align:start position:0% +about in relativity class that you hope + + + align:start position:0% +about in relativity class that you hope +you never hear again right um so + + align:start position:0% +you never hear again right um so + + + align:start position:0% +you never hear again right um so +thinking about this what are some ways + + align:start position:0% +thinking about this what are some ways + + + align:start position:0% +thinking about this what are some ways +that you might do I think we've we've + + align:start position:0% +that you might do I think we've we've + + + align:start position:0% +that you might do I think we've we've +grouped enough I think people want to be + + align:start position:0% +grouped enough I think people want to be + + + align:start position:0% +grouped enough I think people want to be +able to shout and some people whose + + align:start position:0% +able to shout and some people whose + + + align:start position:0% +able to shout and some people whose +names are toward the beginning and end + + align:start position:0% +names are toward the beginning and end + + + align:start position:0% +names are toward the beginning and end +of the alphabet might want to be able to + + align:start position:0% +of the alphabet might want to be able to + + + align:start position:0% +of the alphabet might want to be able to +say so what are some of the things that + + align:start position:0% +say so what are some of the things that + + + align:start position:0% +say so what are some of the things that +a musical duration representation might + + align:start position:0% +a musical duration representation might + + + align:start position:0% +a musical duration representation might +include okay I think that's that's good + + align:start position:0% +include okay I think that's that's good + + + align:start position:0% +include okay I think that's that's good +enough I I I think it's it's sort of + + align:start position:0% +enough I I I think it's it's sort of + + + align:start position:0% +enough I I I think it's it's sort of +like doing jumping jacks you just you + + align:start position:0% +like doing jumping jacks you just you + + + align:start position:0% +like doing jumping jacks you just you +know sort of get get the thinking + + align:start position:0% +know sort of get get the thinking + + + align:start position:0% +know sort of get get the thinking +calisthenics going so um what what's + + align:start position:0% +calisthenics going so um what what's + + + align:start position:0% +calisthenics going so um what what's +some of the things that you might do for + + align:start position:0% +some of the things that you might do for + + + align:start position:0% +some of the things that you might do for +representing duration Jordan said saying + + align:start position:0% +representing duration Jordan said saying + + + align:start position:0% +representing duration Jordan said saying +yeah yeah like seconds or seconds good + + align:start position:0% +yeah yeah like seconds or seconds good + + + align:start position:0% +yeah yeah like seconds or seconds good +now let's think about it um + + align:start position:0% +now let's think about it um + + + align:start position:0% +now let's think about it um +we we'll make our default assumption for + + align:start position:0% +we we'll make our default assumption for + + + align:start position:0% +we we'll make our default assumption for +this class that we're thinking in Python + + align:start position:0% +this class that we're thinking in Python + + + align:start position:0% +this class that we're thinking in Python +of course obviously any halfway decent + + align:start position:0% +of course obviously any halfway decent + + + align:start position:0% +of course obviously any halfway decent +programming language can go for another + + align:start position:0% +programming language can go for another + + + align:start position:0% +programming language can go for another +so how are we going to represent seconds + + align:start position:0% +so how are we going to represent seconds + + + align:start position:0% +so how are we going to represent seconds +for a note yeah go ahead oh was that I + + align:start position:0% +for a note yeah go ahead oh was that I + + + align:start position:0% +for a note yeah go ahead oh was that I +guess like typically don't we use like + + align:start position:0% +guess like typically don't we use like + + + align:start position:0% +guess like typically don't we use like +TI and that kind of like well we'll get + + align:start position:0% +TI and that kind of like well we'll get + + + align:start position:0% +TI and that kind of like well we'll get +to that keep that word there for a + + align:start position:0% +to that keep that word there for a + + + align:start position:0% +to that keep that word there for a +second great but what kind of um what + + align:start position:0% +second great but what kind of um what + + + align:start position:0% +second great but what kind of um what +kind of is string a good + + align:start position:0% +kind of is string a good + + + align:start position:0% +kind of is string a good +one array how are we going to represent + + align:start position:0% +one array how are we going to represent + + + align:start position:0% +one array how are we going to represent +seconds yeah go ahead like a float float + + align:start position:0% +seconds yeah go ahead like a float float + + + align:start position:0% +seconds yeah go ahead like a float float +okay + + align:start position:0% + + + + align:start position:0% + +good why not + + align:start position:0% + + + + align:start position:0% + +int yeah just shout out yep go ahead + + align:start position:0% +int yeah just shout out yep go ahead + + + align:start position:0% +int yeah just shout out yep go ahead +because we can have in between like good + + align:start position:0% +because we can have in between like good + + + align:start position:0% +because we can have in between like good +good we can have in between great super + + align:start position:0% +good we can have in between great super + + + align:start position:0% +good we can have in between great super +um other other things I'm going to uh + + align:start position:0% +um other other things I'm going to uh + + + align:start position:0% +um other other things I'm going to uh +other things you might want ways you + + align:start position:0% +other things you might want ways you + + + align:start position:0% +other things you might want ways you +might want to represent + + align:start position:0% +might want to represent + + + align:start position:0% +might want to represent +duration yeah go ahead Matthew fraction + + align:start position:0% +duration yeah go ahead Matthew fraction + + + align:start position:0% +duration yeah go ahead Matthew fraction +fraction good that fractions seconds as + + align:start position:0% +fraction good that fractions seconds as + + + align:start position:0% +fraction good that fractions seconds as +a fraction or or so thinking both uh + + align:start position:0% +a fraction or or so thinking both uh + + + align:start position:0% +a fraction or or so thinking both uh +represent section seconds as a fraction + + align:start position:0% +represent section seconds as a fraction + + + align:start position:0% +represent section seconds as a fraction +instead of a float so you don't have the + + align:start position:0% +instead of a float so you don't have the + + + align:start position:0% +instead of a float so you don't have the +Precision issues of a float uh um I also + + align:start position:0% +Precision issues of a float uh um I also + + + align:start position:0% +Precision issues of a float uh um I also +think it might make sense to represent + + align:start position:0% +think it might make sense to represent + + + align:start position:0% +think it might make sense to represent +it as a beat and fr okay okay well okay + + align:start position:0% +it as a beat and fr okay okay well okay + + + align:start position:0% +it as a beat and fr okay okay well okay +we go that's that's two things we have + + align:start position:0% +we go that's that's two things we have + + + align:start position:0% +we go that's that's two things we have +beat there good good we'll keep keep + + align:start position:0% +beat there good good we'll keep keep + + + align:start position:0% +beat there good good we'll keep keep +going what are some other things CU um + + align:start position:0% +going what are some other things CU um + + + align:start position:0% +going what are some other things CU um +that we might do yeah I was also + + align:start position:0% +that we might do yeah I was also + + + align:start position:0% +that we might do yeah I was also +thinking fraction but like fraction of + + align:start position:0% +thinking fraction but like fraction of + + + align:start position:0% +thinking fraction but like fraction of +whatever measure you're looking at + + align:start position:0% +whatever measure you're looking at + + + align:start position:0% +whatever measure you're looking at +fraction of measure so if you have like + + align:start position:0% +fraction of measure so if you have like + + + align:start position:0% +fraction of measure so if you have like +a three four + + align:start position:0% +a three four + + + align:start position:0% +a three four +measure and you had a half note that + + align:start position:0% +measure and you had a half note that + + + align:start position:0% +measure and you had a half note that +would be 2/3 of the yep okay so good 2/3 + + align:start position:0% +would be 2/3 of the yep okay so good 2/3 + + + align:start position:0% +would be 2/3 of the yep okay so good 2/3 +that's a particular place where the + + align:start position:0% +that's a particular place where the + + + align:start position:0% +that's a particular place where the +difference between float accuracy and + + align:start position:0% +difference between float accuracy and + + + align:start position:0% +difference between float accuracy and +fraction uh came can can be very very + + align:start position:0% +fraction uh came can can be very very + + + align:start position:0% +fraction uh came can can be very very +important good our beat and fraction of + + align:start position:0% +important good our beat and fraction of + + + align:start position:0% +important good our beat and fraction of +measure um basically saying the same + + align:start position:0% +measure um basically saying the same + + + align:start position:0% +measure um basically saying the same +thing uh with a reciprocal relationship + + align:start position:0% +thing uh with a reciprocal relationship + + + align:start position:0% +thing uh with a reciprocal relationship +can somebody come up with a reason not + + align:start position:0% +can somebody come up with a reason not + + + align:start position:0% +can somebody come up with a reason not +to yess I mean not necessarily because + + align:start position:0% +to yess I mean not necessarily because + + + align:start position:0% +to yess I mean not necessarily because +like something could be on the second + + align:start position:0% +like something could be on the second + + + align:start position:0% +like something could be on the second +beat and have like a duration of one or + + align:start position:0% +beat and have like a duration of one or + + + align:start position:0% +beat and have like a duration of one or +it could be a second beat and have a + + align:start position:0% +it could be a second beat and have a + + + align:start position:0% +it could be a second beat and have a +duration of Two And if it was a fraction + + align:start position:0% +duration of Two And if it was a fraction + + + align:start position:0% +duration of Two And if it was a fraction +of a measure their values would be okay + + align:start position:0% +of a measure their values would be okay + + + align:start position:0% +of a measure their values would be okay +good so we have beat as in what beat is + + align:start position:0% +good so we have beat as in what beat is + + + align:start position:0% +good so we have beat as in what beat is +it on and and that would be very + + align:start position:0% +it on and and that would be very + + + align:start position:0% +it on and and that would be very +different um if we thinking about how + + align:start position:0% +different um if we thinking about how + + + align:start position:0% +different um if we thinking about how +many beats does it last though because + + align:start position:0% +many beats does it last though because + + + align:start position:0% +many beats does it last though because +so thank you Vanessa fantastic um is + + align:start position:0% +so thank you Vanessa fantastic um is + + + align:start position:0% +so thank you Vanessa fantastic um is +that basically the same as what fraction + + align:start position:0% +that basically the same as what fraction + + + align:start position:0% +that basically the same as what fraction +of the measure is + + align:start position:0% +of the measure is + + + align:start position:0% +of the measure is +it thank I see Matthew but I want to + + align:start position:0% +it thank I see Matthew but I want to + + + align:start position:0% +it thank I see Matthew but I want to +want to get I think I'm going this way + + align:start position:0% +want to get I think I'm going this way + + + align:start position:0% +want to get I think I'm going this way +cuz I'm camera shy uh so let me let me + + align:start position:0% +cuz I'm camera shy uh so let me let me + + + align:start position:0% +cuz I'm camera shy uh so let me let me +lean in over here see if there's things + + align:start position:0% +lean in over here see if there's things + + + align:start position:0% +lean in over here see if there's things +are anyone want to who who says it's + + align:start position:0% +are anyone want to who who says it's + + + align:start position:0% +are anyone want to who who says it's +basically the same + + align:start position:0% +basically the same + + + align:start position:0% +basically the same +thing and we can go all the whole room + + align:start position:0% +thing and we can go all the whole room + + + align:start position:0% +thing and we can go all the whole room +who says it's it's it's could be quite + + align:start position:0% + + + + align:start position:0% + +different okay go ahead I guess it was + + align:start position:0% +different okay go ahead I guess it was + + + align:start position:0% +different okay go ahead I guess it was +like depends on what you define the beat + + align:start position:0% +like depends on what you define the beat + + + align:start position:0% +like depends on what you define the beat +as so it's like 58 time or something oh + + align:start position:0% +as so it's like 58 time or something oh + + + align:start position:0% +as so it's like 58 time or something oh +okay so five eight we'll say we'll do it + + align:start position:0% +okay so five eight we'll say we'll do it + + + align:start position:0% +okay so five eight we'll say we'll do it +as this I don't know if people know that + + align:start position:0% +as this I don't know if people know that + + + align:start position:0% +as this I don't know if people know that +symbol um + + align:start position:0% + + + + align:start position:0% + +so how many beats does this + + align:start position:0% +so how many beats does this + + + align:start position:0% +so how many beats does this +get two in some ways and how many this + + align:start position:0% +get two in some ways and how many this + + + align:start position:0% +get two in some ways and how many this +one three good and now give me another + + align:start position:0% +one three good and now give me another + + + align:start position:0% +one three good and now give me another +number that we could use instead of that + + align:start position:0% +number that we could use instead of that + + + align:start position:0% +number that we could use instead of that +for a lot of five8 yeah 106 106 yeah we + + align:start position:0% +for a lot of five8 yeah 106 106 yeah we + + + align:start position:0% +for a lot of five8 yeah 106 106 yeah we +could we could do any other good good we + + align:start position:0% +could we could do any other good good we + + + align:start position:0% +could we could do any other good good we +have an infinite number of non-reduced + + align:start position:0% +have an infinite number of non-reduced + + + align:start position:0% +have an infinite number of non-reduced +fractions we can do great I love that + + align:start position:0% +fractions we can do great I love that + + + align:start position:0% +fractions we can do great I love that +that um how about + + align:start position:0% + + + + align:start position:0% + +this no I won't write that yet + + align:start position:0% +this no I won't write that yet + + + align:start position:0% +this no I won't write that yet +um how many beats does this + + align:start position:0% + + + + align:start position:0% + +get three three is a good answer and + + align:start position:0% +get three three is a good answer and + + + align:start position:0% +get three three is a good answer and +there's another good answer one one from + + align:start position:0% +there's another good answer one one from + + + align:start position:0% +there's another good answer one one from +one one two right so how many beats does + + align:start position:0% +one one two right so how many beats does + + + align:start position:0% +one one two right so how many beats does +this get + + align:start position:0% + + + + align:start position:0% + +so there's some ways of doing it when I + + align:start position:0% +so there's some ways of doing it when I + + + align:start position:0% +so there's some ways of doing it when I +put this symbol I'm saying I'm going to + + align:start position:0% +put this symbol I'm saying I'm going to + + + align:start position:0% +put this symbol I'm saying I'm going to +go one one two one two and they're + + align:start position:0% +go one one two one two and they're + + + align:start position:0% +go one one two one two and they're +they're not so a beat can actually + + align:start position:0% +they're not so a beat can actually + + + align:start position:0% +they're not so a beat can actually +change its length during a measure in + + align:start position:0% +change its length during a measure in + + + align:start position:0% +change its length during a measure in +some representation so this this is one + + align:start position:0% +some representation so this this is one + + + align:start position:0% +some representation so this this is one +of the ways I was thinking not exactly + + align:start position:0% +of the ways I was thinking not exactly + + + align:start position:0% +of the ways I was thinking not exactly +the same same thing but pretty pretty + + align:start position:0% +the same same thing but pretty pretty + + + align:start position:0% +the same same thing but pretty pretty +close good let's see what are some other + + align:start position:0% +close good let's see what are some other + + + align:start position:0% +close good let's see what are some other +ways we might represent duration for a + + align:start position:0% +ways we might represent duration for a + + + align:start position:0% +ways we might represent duration for a +computer + + align:start position:0% +computer + + + align:start position:0% +computer +I'm going to go back to the uh in just a + + align:start position:0% +I'm going to go back to the uh in just a + + + align:start position:0% +I'm going to go back to the uh in just a +little bit the um the names the some of + + align:start position:0% +little bit the um the names the some of + + + align:start position:0% +little bit the um the names the some of +the things I've heard otherwise I heard + + align:start position:0% +the things I've heard otherwise I heard + + + align:start position:0% +the things I've heard otherwise I heard +I heard something over here that um I + + align:start position:0% +I heard something over here that um I + + + align:start position:0% +I heard something over here that um I +think I think Adam or say one of you + + align:start position:0% + + + + align:start position:0% + +Derek like an attribute like a DOT is + + align:start position:0% +Derek like an attribute like a DOT is + + + align:start position:0% +Derek like an attribute like a DOT is +like an attribute great so we might keep + + align:start position:0% +like an attribute great so we might keep + + + align:start position:0% +like an attribute great so we might keep +cheack of attributes like how many dots + + align:start position:0% +cheack of attributes like how many dots + + + align:start position:0% +cheack of attributes like how many dots +does it + + align:start position:0% +does it + + + align:start position:0% +does it +have good anything else like that thank + + align:start position:0% +have good anything else like that thank + + + align:start position:0% +have good anything else like that thank +you + + align:start position:0% + + + + align:start position:0% + +super yeah yeah you take a number for + + align:start position:0% +super yeah yeah you take a number for + + + align:start position:0% +super yeah yeah you take a number for +the nth note it is so if it's an eighth + + align:start position:0% +the nth note it is so if it's an eighth + + + align:start position:0% +the nth note it is so if it's an eighth +note you say eight okay dots would be an + + align:start position:0% +note you say eight okay dots would be an + + + align:start position:0% +note you say eight okay dots would be an +eight dot eight okay so we can represent + + align:start position:0% +eight dot eight okay so we can represent + + + align:start position:0% +eight dot eight okay so we can represent +it as now + + align:start position:0% +it as now + + + align:start position:0% +it as now +um eight dot works pretty well as a + + align:start position:0% +um eight dot works pretty well as a + + + align:start position:0% +um eight dot works pretty well as a +float but is there another way we might + + align:start position:0% +float but is there another way we might + + + align:start position:0% +float but is there another way we might +consider that if we're talking it works + + align:start position:0% +consider that if we're talking it works + + + align:start position:0% +consider that if we're talking it works +well as a string it works better as a + + align:start position:0% +well as a string it works better as a + + + align:start position:0% +well as a string it works better as a +string right because eight dot dot + + align:start position:0% +string right because eight dot dot + + + align:start position:0% +string right because eight dot dot +suddenly you're you're kind of getting a + + align:start position:0% +suddenly you're you're kind of getting a + + + align:start position:0% +suddenly you're you're kind of getting a +crash error right so that's one way you + + align:start position:0% +crash error right so that's one way you + + + align:start position:0% +crash error right so that's one way you +can do it um other + + align:start position:0% +can do it um other + + + align:start position:0% +can do it um other +ways and then so we would say 16 dot or + + align:start position:0% +ways and then so we would say 16 dot or + + + align:start position:0% +ways and then so we would say 16 dot or +something like that good good what are + + align:start position:0% +something like that good good what are + + + align:start position:0% +something like that good good what are +other attributes we might want to + + align:start position:0% +other attributes we might want to + + + align:start position:0% +other attributes we might want to +represent to talk about the duration of + + align:start position:0% +represent to talk about the duration of + + + align:start position:0% +represent to talk about the duration of +a + + align:start position:0% + + + + align:start position:0% + +note are all notes um yeah you could you + + align:start position:0% +note are all notes um yeah you could you + + + align:start position:0% +note are all notes um yeah you could you +could also have things in the triplet + + align:start position:0% +could also have things in the triplet + + + align:start position:0% +could also have things in the triplet +you could have things in the + + align:start position:0% + + + + align:start position:0% + +triplet yeah + + align:start position:0% + + + + align:start position:0% + +good you can also have things in a + + align:start position:0% +good you can also have things in a + + + align:start position:0% +good you can also have things in a +quintuplet right see if I can squeeze + + align:start position:0% +quintuplet right see if I can squeeze + + + align:start position:0% +quintuplet right see if I can squeeze +this + + align:start position:0% +this + + + align:start position:0% +this +in and you can also have + + align:start position:0% + + + + align:start position:0% + +things in a triplet within a + + align:start position:0% +things in a triplet within a + + + align:start position:0% +things in a triplet within a +quintuplet this is called nested tuplets + + align:start position:0% +quintuplet this is called nested tuplets + + + align:start position:0% +quintuplet this is called nested tuplets +um + + align:start position:0% +um + + + align:start position:0% +um +so I will guarantee you I have seen at + + align:start position:0% +so I will guarantee you I have seen at + + + align:start position:0% +so I will guarantee you I have seen at +least 20 representations of notated + + align:start position:0% +least 20 representations of notated + + + align:start position:0% +least 20 representations of notated +durations where the tuplet was + + align:start position:0% +durations where the tuplet was + + + align:start position:0% +durations where the tuplet was +originally created as an attribute and + + align:start position:0% +originally created as an attribute and + + + align:start position:0% +originally created as an attribute and +then it needed to be represented as a + + align:start position:0% +then it needed to be represented as a + + + align:start position:0% +then it needed to be represented as a +list array uh tupple something like that + + align:start position:0% +list array uh tupple something like that + + + align:start position:0% +list array uh tupple something like that +of a tupple of tuplets try to say that + + align:start position:0% +of a tupple of tuplets try to say that + + + align:start position:0% +of a tupple of tuplets try to say that +10 times fast um for a indeterminate + + align:start position:0% +10 times fast um for a indeterminate + + + align:start position:0% +10 times fast um for a indeterminate +number of tuplets that might be applied + + align:start position:0% +number of tuplets that might be applied + + + align:start position:0% +number of tuplets that might be applied +to a certain notes so these might be + + align:start position:0% +to a certain notes so these might be + + + align:start position:0% +to a certain notes so these might be +certain things good uh anything else + + align:start position:0% +certain things good uh anything else + + + align:start position:0% +certain things good uh anything else +that we might use to represent duration + + align:start position:0% +that we might use to represent duration + + + align:start position:0% +that we might use to represent duration +yeah go ahead certain markings like + + align:start position:0% +yeah go ahead certain markings like + + + align:start position:0% +yeah go ahead certain markings like +Stato or like good so we might have um + + align:start position:0% +Stato or like good so we might have um + + + align:start position:0% +Stato or like good so we might have um +modifying Ying uh I don't know + + align:start position:0% +modifying Ying uh I don't know + + + align:start position:0% +modifying Ying uh I don't know +articulations and expressions or + + align:start position:0% +articulations and expressions or + + + align:start position:0% +articulations and expressions or +markings well it's called markings + + align:start position:0% +markings well it's called markings + + + align:start position:0% +markings well it's called markings +because who knows what they are + + align:start position:0% +because who knows what they are + + + align:start position:0% +because who knows what they are +markings I'll make a formada on my eye + + align:start position:0% +markings I'll make a formada on my eye + + + align:start position:0% +markings I'll make a formada on my eye +good so um yeah we have our dots + + align:start position:0% +good so um yeah we have our dots + + + align:start position:0% +good so um yeah we have our dots +maybe more defin + + align:start position:0% +maybe more defin + + + align:start position:0% +maybe more defin +good so we can think of tudos that those + + align:start position:0% +good so we can think of tudos that those + + + align:start position:0% +good so we can think of tudos that those +affect the duration great now I don't + + align:start position:0% +affect the duration great now I don't + + + align:start position:0% +affect the duration great now I don't +want to um go too much further on this + + align:start position:0% +want to um go too much further on this + + + align:start position:0% +want to um go too much further on this +um now our music is on uh I was going to + + align:start position:0% +um now our music is on uh I was going to + + + align:start position:0% +um now our music is on uh I was going to +use obsolete formats a CD or streaming + + align:start position:0% +use obsolete formats a CD or streaming + + + align:start position:0% +use obsolete formats a CD or streaming +what are the most um useful + + align:start position:0% +what are the most um useful + + + align:start position:0% +what are the most um useful +representations of + + align:start position:0% + + + + align:start position:0% + +duration of notes let's + + align:start position:0% +duration of notes let's + + + align:start position:0% +duration of notes let's +say or other things which ones of these + + align:start position:0% +say or other things which ones of these + + + align:start position:0% +say or other things which ones of these +are most + + align:start position:0% + + + + align:start position:0% + +useful yeah I've heard you a couple + + align:start position:0% +useful yeah I've heard you a couple + + + align:start position:0% +useful yeah I've heard you a couple +times from you so great super Ms got it + + align:start position:0% +times from you so great super Ms got it + + + align:start position:0% +times from you so great super Ms got it +who else got + + align:start position:0% + + + + align:start position:0% + +one is this a great duration that you a + + align:start position:0% +one is this a great duration that you a + + + align:start position:0% +one is this a great duration that you a +representation that you're hearing of + + align:start position:0% +representation that you're hearing of + + + align:start position:0% +representation that you're hearing of +the duration of a note when you're + + align:start position:0% +the duration of a note when you're + + + align:start position:0% +the duration of a note when you're +listening to streaming + + align:start position:0% + + + + align:start position:0% + +music maybe not but but boy that could + + align:start position:0% +music maybe not but but boy that could + + + align:start position:0% +music maybe not but but boy that could +be useful for other things what about + + align:start position:0% + + + + align:start position:0% + +seconds that's going to depend + + align:start position:0% +seconds that's going to depend + + + align:start position:0% +seconds that's going to depend +on let's say you're listening just for + + align:start position:0% +on let's say you're listening just for + + + align:start position:0% +on let's say you're listening just for +fun seconds very good no maybe not I + + align:start position:0% +fun seconds very good no maybe not I + + + align:start position:0% +fun seconds very good no maybe not I +don't I don't usually hear seconds but + + align:start position:0% +don't I don't usually hear seconds but + + + align:start position:0% +don't I don't usually hear seconds but +who's somebody who involved in the + + align:start position:0% +who's somebody who involved in the + + + align:start position:0% +who's somebody who involved in the +streaming music process who might really + + align:start position:0% +streaming music process who might really + + + align:start position:0% +streaming music process who might really +care about seconds of + + align:start position:0% + + + + align:start position:0% + +notes I guess like computers the + + align:start position:0% +notes I guess like computers the + + + align:start position:0% +notes I guess like computers the +computers why yep and and but what kind + + align:start position:0% +computers why yep and and but what kind + + + align:start position:0% +computers why yep and and but what kind +of human might might be really + + align:start position:0% +of human might might be really + + + align:start position:0% +of human might might be really +interested yeah some editor person the + + align:start position:0% +interested yeah some editor person the + + + align:start position:0% +interested yeah some editor person the +editor yeah the um the person who's + + align:start position:0% +editor yeah the um the person who's + + + align:start position:0% +editor yeah the um the person who's +doing the recording editing they're + + align:start position:0% +doing the recording editing they're + + + align:start position:0% +doing the recording editing they're +always going to be thinking about uh + + align:start position:0% +always going to be thinking about uh + + + align:start position:0% +always going to be thinking about uh +okay let's clip from 22.4 6 to 22.0 48 + + align:start position:0% +okay let's clip from 22.4 6 to 22.0 48 + + + align:start position:0% +okay let's clip from 22.4 6 to 22.0 48 +when somebody coughed and will will'll + + align:start position:0% +when somebody coughed and will will'll + + + align:start position:0% +when somebody coughed and will will'll +come up with something right so those + + align:start position:0% +come up with something right so those + + + align:start position:0% +come up with something right so those +types of things come up quite a bit in + + align:start position:0% +types of things come up quite a bit in + + + align:start position:0% +types of things come up quite a bit in +in that type of World um now what if + + align:start position:0% +in that type of World um now what if + + + align:start position:0% +in that type of World um now what if +we're um you've written your Great Piece + + align:start position:0% +we're um you've written your Great Piece + + + align:start position:0% +we're um you've written your Great Piece +it's already been recorded performed and + + align:start position:0% +it's already been recorded performed and + + + align:start position:0% +it's already been recorded performed and +things and now youve send it off to your + + align:start position:0% +things and now youve send it off to your + + + align:start position:0% +things and now youve send it off to your +sheet music publisher what are the ones + + align:start position:0% +sheet music publisher what are the ones + + + align:start position:0% +sheet music publisher what are the ones +they're going to Care the most + + align:start position:0% + + + + align:start position:0% + +about's some what's a representation + + align:start position:0% +about's some what's a representation + + + align:start position:0% +about's some what's a representation +yeah John PCH dur duration the pitch and + + align:start position:0% +yeah John PCH dur duration the pitch and + + + align:start position:0% +yeah John PCH dur duration the pitch and +the duration good and how are they going + + align:start position:0% +the duration good and how are they going + + + align:start position:0% +the duration good and how are they going +to be thinking about duration how's the + + align:start position:0% +to be thinking about duration how's the + + + align:start position:0% +to be thinking about duration how's the +engraver um that's the person who who + + align:start position:0% +engraver um that's the person who who + + + align:start position:0% +engraver um that's the person who who +makes musical scores the term for that + + align:start position:0% +makes musical scores the term for that + + + align:start position:0% +makes musical scores the term for that +um what's what's the engraver what's she + + align:start position:0% +um what's what's the engraver what's she + + + align:start position:0% +um what's what's the engraver what's she +going to be um thinking about in terms + + align:start position:0% +going to be um thinking about in terms + + + align:start position:0% +going to be um thinking about in terms +of + + align:start position:0% + + + + align:start position:0% + +duration what do you think about when + + align:start position:0% +duration what do you think about when + + + align:start position:0% +duration what do you think about when +you when you're looking at musical score + + align:start position:0% +you when you're looking at musical score + + + align:start position:0% +you when you're looking at musical score +yeah um the beat and the modifying the + + align:start position:0% +yeah um the beat and the modifying the + + + align:start position:0% +yeah um the beat and the modifying the +beats the modifi good good the um what + + align:start position:0% +beats the modifi good good the um what + + + align:start position:0% +beats the modifi good good the um what +do what are we going to call something + + align:start position:0% +do what are we going to call something + + + align:start position:0% +do what are we going to call something +uh the difference between an eighth note + + align:start position:0% +uh the difference between an eighth note + + + align:start position:0% +uh the difference between an eighth note +a quarter note a half note St all that + + align:start position:0% +a quarter note a half note St all that + + + align:start position:0% +a quarter note a half note St all that +stuff what do what do we want to call + + align:start position:0% +stuff what do what do we want to call + + + align:start position:0% +stuff what do what do we want to call +that do we we all have been doing music + + align:start position:0% +that do we we all have been doing music + + + align:start position:0% +that do we we all have been doing music +for a very long time we all must know + + align:start position:0% +for a very long time we all must know + + + align:start position:0% +for a very long time we all must know +the term for that + + align:start position:0% + + + + align:start position:0% + +right there is no generalized term for + + align:start position:0% +right there is no generalized term for + + + align:start position:0% +right there is no generalized term for +it so what do we want to call it in this + + align:start position:0% + + + + align:start position:0% + +class somebody shout out something or + + align:start position:0% +class somebody shout out something or + + + align:start position:0% +class somebody shout out something or +we'll call it the the the note animal + + align:start position:0% +we'll call it the the the note animal + + + align:start position:0% +we'll call it the the the note animal +what what animal is this note or what + + align:start position:0% +what what animal is this note or what + + + align:start position:0% +what what animal is this note or what +flavor is this note that's a good one + + align:start position:0% +flavor is this note that's a good one + + + align:start position:0% +flavor is this note that's a good one +actually I wish I had gone with that um + + align:start position:0% +actually I wish I had gone with that um + + + align:start position:0% +actually I wish I had gone with that um +16th notes are really really tasty + + align:start position:0% +16th notes are really really tasty + + + align:start position:0% +16th notes are really really tasty +today anybody have a suggestion of a + + align:start position:0% + + + + align:start position:0% + +term Essence the essence what essence of + + align:start position:0% +term Essence the essence what essence of + + + align:start position:0% +term Essence the essence what essence of +note is good good I will tell you that + + align:start position:0% +note is good good I will tell you that + + + align:start position:0% +note is good good I will tell you that +Essence is better than animal probably + + align:start position:0% +Essence is better than animal probably + + + align:start position:0% +Essence is better than animal probably +as a term it's probably better than + + align:start position:0% +as a term it's probably better than + + + align:start position:0% +as a term it's probably better than +flavor and it's better than what all the + + align:start position:0% +flavor and it's better than what all the + + + align:start position:0% +flavor and it's better than what all the +rest of us didn't say because the first + + align:start position:0% +rest of us didn't say because the first + + + align:start position:0% +rest of us didn't say because the first +thing you have to do when you're + + align:start position:0% +thing you have to do when you're + + + align:start position:0% +thing you have to do when you're +representing for a computer is come up + + align:start position:0% +representing for a computer is come up + + + align:start position:0% +representing for a computer is come up +with a name for everything yeah Vanessa + + align:start position:0% +with a name for everything yeah Vanessa + + + align:start position:0% +with a name for everything yeah Vanessa +oh no okay but come up with a name for + + align:start position:0% +oh no okay but come up with a name for + + + align:start position:0% +oh no okay but come up with a name for +it what duration the duration okay so we + + align:start position:0% +it what duration the duration okay so we + + + align:start position:0% +it what duration the duration okay so we +might have the duration of a duration is + + align:start position:0% +might have the duration of a duration is + + + align:start position:0% +might have the duration of a duration is +a quarter and the number of dots is two + + align:start position:0% +a quarter and the number of dots is two + + + align:start position:0% +a quarter and the number of dots is two +a lot of representations do that the um + + align:start position:0% +a lot of representations do that the um + + + align:start position:0% +a lot of representations do that the um +I think Mei calls that part A duration + + align:start position:0% +I think Mei calls that part A duration + + + align:start position:0% +I think Mei calls that part A duration +so that's a very good term for it other + + align:start position:0% +so that's a very good term for it other + + + align:start position:0% +so that's a very good term for it other +other + + align:start position:0% + + + + align:start position:0% + +terms get good at naming things come up + + align:start position:0% +terms get good at naming things come up + + + align:start position:0% +terms get good at naming things come up +with names fast in this class so let's + + align:start position:0% +with names fast in this class so let's + + + align:start position:0% +with names fast in this class so let's +let's just pepper pepper some pepper + + align:start position:0% +let's just pepper pepper some pepper + + + align:start position:0% +let's just pepper pepper some pepper +some bad names for it Jonathan what's + + align:start position:0% +some bad names for it Jonathan what's + + + align:start position:0% +some bad names for it Jonathan what's +what's that almond the Almond what + + align:start position:0% +what's that almond the Almond what + + + align:start position:0% +what's that almond the Almond what +Almond is it I + + align:start position:0% +Almond is it I + + + align:start position:0% +Almond is it I +think I mean I the length what length + + align:start position:0% +think I mean I the length what length + + + align:start position:0% +think I mean I the length what length +good what length does that not it's a + + align:start position:0% +good what length does that not it's a + + + align:start position:0% +good what length does that not it's a +quarter note what length does that know + + align:start position:0% +quarter note what length does that know + + + align:start position:0% +quarter note what length does that know +it's an eth note there might be a better + + align:start position:0% +it's an eth note there might be a better + + + align:start position:0% +it's an eth note there might be a better +term but that's a pretty good one that's + + align:start position:0% +term but that's a pretty good one that's + + + align:start position:0% +term but that's a pretty good one that's +good yeah I feel like span isn't what + + align:start position:0% +good yeah I feel like span isn't what + + + align:start position:0% +good yeah I feel like span isn't what +span I like that what span I it might + + align:start position:0% +span I like that what span I it might + + + align:start position:0% +span I like that what span I it might +not be so so perfect but you know it's + + align:start position:0% +not be so so perfect but you know it's + + + align:start position:0% +not be so so perfect but you know it's +it gets us when you think think about + + align:start position:0% +it gets us when you think think about + + + align:start position:0% +it gets us when you think think about +things what's something that expands um + + align:start position:0% +things what's something that expands um + + + align:start position:0% +things what's something that expands um +things that people uh spend a lot of + + align:start position:0% +things that people uh spend a lot of + + + align:start position:0% +things that people uh spend a lot of +time especially what course three uh + + align:start position:0% +time especially what course three uh + + + align:start position:0% +time especially what course three uh +thinking + + align:start position:0% + + + + align:start position:0% + +about bridges good and when you start + + align:start position:0% +about bridges good and when you start + + + align:start position:0% +about bridges good and when you start +thinking about bridges what's something + + align:start position:0% +thinking about bridges what's something + + + align:start position:0% +thinking about bridges what's something +that we haven't even thought of that + + align:start position:0% +that we haven't even thought of that + + + align:start position:0% +that we haven't even thought of that +looks like a bridge when we think about + + align:start position:0% +looks like a bridge when we think about + + + align:start position:0% +looks like a bridge when we think about +durations and notes slurs slurs ties + + align:start position:0% +durations and notes slurs slurs ties + + + align:start position:0% +durations and notes slurs slurs ties +good slurs ties I was also thinking of + + align:start position:0% +good slurs ties I was also thinking of + + + align:start position:0% +good slurs ties I was also thinking of +beams any of those good so start when we + + align:start position:0% +beams any of those good so start when we + + + align:start position:0% +beams any of those good so start when we +start thinking of terms like this we + + align:start position:0% +start thinking of terms like this we + + + align:start position:0% +start thinking of terms like this we +start thinking of cases who had thought + + align:start position:0% +start thinking of cases who had thought + + + align:start position:0% +start thinking of cases who had thought +about ties and slurs in your + + align:start position:0% +about ties and slurs in your + + + align:start position:0% +about ties and slurs in your +definition who had thought about + + align:start position:0% +definition who had thought about + + + align:start position:0% +definition who had thought about +Beams I I hadn't thought of TI and so + + align:start position:0% +Beams I I hadn't thought of TI and so + + + align:start position:0% +Beams I I hadn't thought of TI and so +when we do these types of things + + align:start position:0% +when we do these types of things + + + align:start position:0% +when we do these types of things +suddenly why something is a good name or + + align:start position:0% +suddenly why something is a good name or + + + align:start position:0% +suddenly why something is a good name or +might not be a good name can help us + + align:start position:0% +might not be a good name can help us + + + align:start position:0% +might not be a good name can help us +think about what other things we're + + align:start position:0% +think about what other things we're + + + align:start position:0% +think about what other things we're +going to have to represent I'm looking + + align:start position:0% +going to have to represent I'm looking + + + align:start position:0% +going to have to represent I'm looking +at the time we're not going to be able + + align:start position:0% +at the time we're not going to be able + + + align:start position:0% +at the time we're not going to be able +to get through all the different types + + align:start position:0% +to get through all the different types + + + align:start position:0% +to get through all the different types +of representations here but but good now + + align:start position:0% +of representations here but but good now + + + align:start position:0% +of representations here but but good now +what would it + + align:start position:0% +what would it + + + align:start position:0% +what would it +take let's say you have + + align:start position:0% + + + + align:start position:0% + +this what's it going to take that's a + + align:start position:0% +this what's it going to take that's a + + + align:start position:0% +this what's it going to take that's a +dotted quarter note that's not a not a + + align:start position:0% +dotted quarter note that's not a not a + + + align:start position:0% +dotted quarter note that's not a not a +trick question what's it going to take + + align:start position:0% +trick question what's it going to take + + + align:start position:0% +trick question what's it going to take +for you to figure out how many seconds + + align:start position:0% +for you to figure out how many seconds + + + align:start position:0% +for you to figure out how many seconds +that is who has performed music from + + align:start position:0% +that is who has performed music from + + + align:start position:0% +that is who has performed music from +sheet music in this class in your life + + align:start position:0% +sheet music in this class in your life + + + align:start position:0% +sheet music in this class in your life +okay it's basically + + align:start position:0% +okay it's basically + + + align:start position:0% +okay it's basically +everybody so when you do that you have + + align:start position:0% +everybody so when you do that you have + + + align:start position:0% +everybody so when you do that you have +to decide how long you're going to play + + align:start position:0% +to decide how long you're going to play + + + align:start position:0% +to decide how long you're going to play +that right you might not even be + + align:start position:0% +that right you might not even be + + + align:start position:0% +that right you might not even be +thinking it in your head I've never been + + align:start position:0% +thinking it in your head I've never been + + + align:start position:0% +thinking it in your head I've never been +like okay I'm going to play that for3 3 + + align:start position:0% +like okay I'm going to play that for3 3 + + + align:start position:0% +like okay I'm going to play that for3 3 +six5 + + align:start position:0% +six5 + + + align:start position:0% +six5 +seconds um how do we how do we go from + + align:start position:0% +seconds um how do we how do we go from + + + align:start position:0% +seconds um how do we how do we go from +this to a number of + + align:start position:0% +this to a number of + + + align:start position:0% +this to a number of +seconds yeah good oh sorry there was two + + align:start position:0% +seconds yeah good oh sorry there was two + + + align:start position:0% +seconds yeah good oh sorry there was two +in a row going behind first U well it's + + align:start position:0% +in a row going behind first U well it's + + + align:start position:0% +in a row going behind first U well it's +based off the tempo based off the tempo + + align:start position:0% +based off the tempo based off the tempo + + + align:start position:0% +based off the tempo based off the tempo +good has Tempo been included I suppose + + align:start position:0% +good has Tempo been included I suppose + + + align:start position:0% +good has Tempo been included I suppose +it's almost implicitly included in beat + + align:start position:0% +it's almost implicitly included in beat + + + align:start position:0% +it's almost implicitly included in beat +but Tempo is this particular term so we + + align:start position:0% +but Tempo is this particular term so we + + + align:start position:0% +but Tempo is this particular term so we +have Tempo how do we measure tempos + + align:start position:0% +have Tempo how do we measure tempos + + + align:start position:0% +have Tempo how do we measure tempos +Tempe Tempe + + align:start position:0% +Tempe Tempe + + + align:start position:0% +Tempe Tempe +what's that be beat per minute + + align:start position:0% +what's that be beat per minute + + + align:start position:0% +what's that be beat per minute +good beat per + + align:start position:0% +good beat per + + + align:start position:0% +good beat per +minute so what do we need to know also + + align:start position:0% +minute so what do we need to know also + + + align:start position:0% +minute so what do we need to know also +in addition to Tempo in order to figure + + align:start position:0% +in addition to Tempo in order to figure + + + align:start position:0% +in addition to Tempo in order to figure +out how many beats something + + align:start position:0% + + + + align:start position:0% + +is we all think of 44 right so yeah Jake + + align:start position:0% +is we all think of 44 right so yeah Jake + + + align:start position:0% +is we all think of 44 right so yeah Jake +you intentionally say 365 because it's + + align:start position:0% +you intentionally say 365 because it's + + + align:start position:0% +you intentionally say 365 because it's +38 of + + align:start position:0% +38 of + + + align:start position:0% +38 of +the7 375 but yeah whatever I I don't + + align:start position:0% +the7 375 but yeah whatever I I don't + + + align:start position:0% +the7 375 but yeah whatever I I don't +know it was something something like + + align:start position:0% +know it was something something like + + + align:start position:0% +know it was something something like +that yeah I I I I very rarely do + + align:start position:0% +that yeah I I I I very rarely do + + + align:start position:0% +that yeah I I I I very rarely do +anything intentionally so so maybe it's + + align:start position:0% +anything intentionally so so maybe it's + + + align:start position:0% +anything intentionally so so maybe it's +karma um uh what do we need to do to get + + align:start position:0% +karma um uh what do we need to do to get + + + align:start position:0% +karma um uh what do we need to do to get +beats per minute how many beats is + + align:start position:0% +beats per minute how many beats is + + + align:start position:0% +beats per minute how many beats is +this depends depends good depends on the + + align:start position:0% +this depends depends good depends on the + + + align:start position:0% +this depends depends good depends on the +everybody shout it out time signature + + align:start position:0% +everybody shout it out time signature + + + align:start position:0% +everybody shout it out time signature +good so suddenly moving from this + + align:start position:0% +good so suddenly moving from this + + + align:start position:0% +good so suddenly moving from this +representation of notes to seconds we + + align:start position:0% +representation of notes to seconds we + + + align:start position:0% +representation of notes to seconds we +need Tempo in beats per minute and a + + align:start position:0% +need Tempo in beats per minute and a + + + align:start position:0% +need Tempo in beats per minute and a +time + + align:start position:0% +time + + + align:start position:0% +time +signature + + align:start position:0% +signature + + + align:start position:0% +signature +good let me give you another one what if + + align:start position:0% +good let me give you another one what if + + + align:start position:0% +good let me give you another one what if +I said the tempo here + + align:start position:0% +I said the tempo here + + + align:start position:0% +I said the tempo here +was + + align:start position:0% +was + + + align:start position:0% +was +Alro ma non + + align:start position:0% +Alro ma non + + + align:start position:0% +Alro ma non +tropo okay the other thing if it gets + + align:start position:0% +tropo okay the other thing if it gets + + + align:start position:0% +tropo okay the other thing if it gets +too much longer than that the other + + align:start position:0% +too much longer than that the other + + + align:start position:0% +too much longer than that the other +thing we need is an Italian dictionary + + align:start position:0% +thing we need is an Italian dictionary + + + align:start position:0% +thing we need is an Italian dictionary +right U algro but not too Allegro not + + align:start position:0% +right U algro but not too Allegro not + + + align:start position:0% +right U algro but not too Allegro not +too much um so what do we need also in + + align:start position:0% +too much um so what do we need also in + + + align:start position:0% +too much um so what do we need also in +order to convert this to seconds + + align:start position:0% + + + + align:start position:0% + +let's take a take a stab at it you guys + + align:start position:0% +let's take a take a stab at it you guys + + + align:start position:0% +let's take a take a stab at it you guys +have all been speaking pretty well + + align:start position:0% +have all been speaking pretty well + + + align:start position:0% +have all been speaking pretty well +Hannah I don't think I've heard from you + + align:start position:0% +Hannah I don't think I've heard from you + + + align:start position:0% +Hannah I don't think I've heard from you +in a little bit what would you say you + + align:start position:0% +in a little bit what would you say you + + + align:start position:0% +in a little bit what would you say you +need in order to convert this to I say + + align:start position:0% +need in order to convert this to I say + + + align:start position:0% +need in order to convert this to I say +knowledge of + + align:start position:0% +knowledge of + + + align:start position:0% +knowledge of +what knowledge of like what it means in + + align:start position:0% +what knowledge of like what it means in + + + align:start position:0% +what knowledge of like what it means in +terms of the temp knowledge of good + + align:start position:0% +terms of the temp knowledge of good + + + align:start position:0% +terms of the temp knowledge of good +knowledge of a conversion do can you + + align:start position:0% +knowledge of a conversion do can you + + + align:start position:0% +knowledge of a conversion do can you +give me a conversion maybe what it means + + align:start position:0% +give me a conversion maybe what it means + + + align:start position:0% +give me a conversion maybe what it means +what it a conversion to let's say + + align:start position:0% +what it a conversion to let's say + + + align:start position:0% +what it a conversion to let's say +BPM what would be uh what's somebody uh + + align:start position:0% +BPM what would be uh what's somebody uh + + + align:start position:0% +BPM what would be uh what's somebody uh +Hannah if you want to or pass it along + + align:start position:0% +Hannah if you want to or pass it along + + + align:start position:0% +Hannah if you want to or pass it along +to somebody else take stab what are you + + align:start position:0% +to somebody else take stab what are you + + + align:start position:0% +to somebody else take stab what are you +going to name + + align:start position:0% +going to name + + + align:start position:0% +going to name +that algro + + align:start position:0% + + + + align:start position:0% + +approximately seven no okay two million + + align:start position:0% +approximately seven no okay two million + + + align:start position:0% +approximately seven no okay two million +no okay good we we're we're narrowing it + + align:start position:0% +no okay good we we're we're narrowing it + + + align:start position:0% +no okay good we we're we're narrowing it +down uhbe around like 110 110 + + align:start position:0% +down uhbe around like 110 110 + + + align:start position:0% +down uhbe around like 110 110 +good anybody want to go higher than 110 + + align:start position:0% +good anybody want to go higher than 110 + + + align:start position:0% +good anybody want to go higher than 110 +what do you want to go with 126 + + align:start position:0% +what do you want to go with 126 + + + align:start position:0% +what do you want to go with 126 +126 very specific number um any anyone + + align:start position:0% +126 very specific number um any anyone + + + align:start position:0% +126 very specific number um any anyone +want to go + + align:start position:0% + + + + align:start position:0% + +lower I'm going to go a little bit lower + + align:start position:0% +lower I'm going to go a little bit lower + + + align:start position:0% +lower I'm going to go a little bit lower +and say + + align:start position:0% +and say + + + align:start position:0% +and say +90 because the other thing that you need + + align:start position:0% +90 because the other thing that you need + + + align:start position:0% +90 because the other thing that you need +to know is the cultural + + align:start position:0% +to know is the cultural + + + align:start position:0% +to know is the cultural +context and + + align:start position:0% +context and + + + align:start position:0% +context and +because each of these + + align:start position:0% +because each of these + + + align:start position:0% +because each of these +things changes so much handle has a + + align:start position:0% +things changes so much handle has a + + + align:start position:0% +things changes so much handle has a +Tempo marking of Allegro + + align:start position:0% + + + + align:start position:0% + +Adagio what does that mean those are + + align:start position:0% +Adagio what does that mean those are + + + align:start position:0% +Adagio what does that mean those are +like contradictions that's like you know + + align:start position:0% +like contradictions that's like you know + + + align:start position:0% +like contradictions that's like you know +how how do you like your cereal I like a + + align:start position:0% +how how do you like your cereal I like a + + + align:start position:0% +how how do you like your cereal I like a +hot cold um yeah but at a particular + + align:start position:0% +hot cold um yeah but at a particular + + + align:start position:0% +hot cold um yeah but at a particular +time that is so sometimes we ignore + + align:start position:0% +time that is so sometimes we ignore + + + align:start position:0% +time that is so sometimes we ignore +quite a lot of these right uh I know I + + align:start position:0% +quite a lot of these right uh I know I + + + align:start position:0% +quite a lot of these right uh I know I +use uh and by the way Han I pretty close + + align:start position:0% +use uh and by the way Han I pretty close + + + align:start position:0% +use uh and by the way Han I pretty close +I think I use 118 in a lookup table when + + align:start position:0% +I think I use 118 in a lookup table when + + + align:start position:0% +I think I use 118 in a lookup table when +I have no idea what I want to do from + + align:start position:0% +I have no idea what I want to do from + + + align:start position:0% +I have no idea what I want to do from +Allegro um or sometimes I've used 126 + + align:start position:0% +Allegro um or sometimes I've used 126 + + + align:start position:0% +Allegro um or sometimes I've used 126 +I've used other things 110 110 I usually + + align:start position:0% +I've used other things 110 110 I usually + + + align:start position:0% +I've used other things 110 110 I usually +use as the the it depends on whether or + + align:start position:0% +use as the the it depends on whether or + + + align:start position:0% +use as the the it depends on whether or +not I have a conception of the term Alig + + align:start position:0% +not I have a conception of the term Alig + + + align:start position:0% +not I have a conception of the term Alig +gretto in which case I need to make room + + align:start position:0% +gretto in which case I need to make room + + + align:start position:0% +gretto in which case I need to make room +for that but yeah 11's also very good uh + + align:start position:0% +for that but yeah 11's also very good uh + + + align:start position:0% +for that but yeah 11's also very good uh +good by the way every guess that people + + align:start position:0% +good by the way every guess that people + + + align:start position:0% +good by the way every guess that people +are doing has been really really really + + align:start position:0% +are doing has been really really really + + + align:start position:0% +are doing has been really really really +good in this class so just just keep + + align:start position:0% +good in this class so just just keep + + + align:start position:0% +good in this class so just just keep +taking the guess and I'll when we start + + align:start position:0% +taking the guess and I'll when we start + + + align:start position:0% +taking the guess and I'll when we start +talking too much then I'll you know then + + align:start position:0% +talking too much then I'll you know then + + + align:start position:0% +talking too much then I'll you know then +I'll I'll slow it down but good so these + + align:start position:0% +I'll I'll slow it down but good so these + + + align:start position:0% +I'll I'll slow it down but good so these +are all the various things that we might + + align:start position:0% +are all the various things that we might + + + align:start position:0% +are all the various things that we might +do to convert from one to another um + + align:start position:0% +do to convert from one to another um + + + align:start position:0% +do to convert from one to another um +there was one other Tempo um uh one + + align:start position:0% +there was one other Tempo um uh one + + + align:start position:0% +there was one other Tempo um uh one +other way that we could measure duration + + align:start position:0% +other way that we could measure duration + + + align:start position:0% +other way that we could measure duration +that I think uh Marlin said um that I + + align:start position:0% +that I think uh Marlin said um that I + + + align:start position:0% +that I think uh Marlin said um that I +was like sh not yet not yet not yet but + + align:start position:0% +was like sh not yet not yet not yet but + + + align:start position:0% +was like sh not yet not yet not yet but +comes very important do you remember + + align:start position:0% +comes very important do you remember + + + align:start position:0% +comes very important do you remember +what we said tick ticks good so you can + + align:start position:0% +what we said tick ticks good so you can + + + align:start position:0% +what we said tick ticks good so you can +measure on the number of bugs that get + + align:start position:0% +measure on the number of bugs that get + + + align:start position:0% +measure on the number of bugs that get +into your hair when you go hiking right + + align:start position:0% +into your hair when you go hiking right + + + align:start position:0% +into your hair when you go hiking right +no what do we what do we mean by a tick + + align:start position:0% +no what do we what do we mean by a tick + + + align:start position:0% +no what do we what do we mean by a tick +this has a different meaning than from + + align:start position:0% +this has a different meaning than from + + + align:start position:0% +this has a different meaning than from +my understanding is how like the + + align:start position:0% +my understanding is how like the + + + align:start position:0% +my understanding is how like the +computers process like whatever program + + align:start position:0% +computers process like whatever program + + + align:start position:0% +computers process like whatever program +or application and that me kind of like + + align:start position:0% +or application and that me kind of like + + + align:start position:0% +or application and that me kind of like +tis and so that kind of dictates how + + align:start position:0% +tis and so that kind of dictates how + + + align:start position:0% +tis and so that kind of dictates how +what a second is based on great yeah so + + align:start position:0% +what a second is based on great yeah so + + + align:start position:0% +what a second is based on great yeah so +what we can do is we can think of time + + align:start position:0% +what we can do is we can think of time + + + align:start position:0% +what we can do is we can think of time +as somehow + + align:start position:0% +as somehow + + + align:start position:0% +as somehow +discreet that time moves forward and by + + align:start position:0% +discreet that time moves forward and by + + + align:start position:0% +discreet that time moves forward and by +the way there's some there's some uh + + align:start position:0% +the way there's some there's some uh + + + align:start position:0% +the way there's some there's some uh +theoretical physicists who've been uh + + align:start position:0% +theoretical physicists who've been uh + + + align:start position:0% +theoretical physicists who've been uh +trying to study whether time actually is + + align:start position:0% +trying to study whether time actually is + + + align:start position:0% +trying to study whether time actually is +discrete and moves forward in know 10 to + + align:start position:0% +discrete and moves forward in know 10 to + + + align:start position:0% +discrete and moves forward in know 10 to +the Nega + + align:start position:0% +the Nega + + + align:start position:0% +the Nega +58 seconds or not um but but that we can + + align:start position:0% +58 seconds or not um but but that we can + + + align:start position:0% +58 seconds or not um but but that we can +think of musical time as a screet number + + align:start position:0% +think of musical time as a screet number + + + align:start position:0% +think of musical time as a screet number +of something in a purely computer world + + align:start position:0% +of something in a purely computer world + + + align:start position:0% +of something in a purely computer world +like + + align:start position:0% +like + + + align:start position:0% +like +tix which is both brilliant and a way of + + align:start position:0% +tix which is both brilliant and a way of + + + align:start position:0% +tix which is both brilliant and a way of +just um shuffling later to some other + + align:start position:0% +just um shuffling later to some other + + + align:start position:0% +just um shuffling later to some other +later part of the program the actual + + align:start position:0% +later part of the program the actual + + + align:start position:0% +later part of the program the actual +conversion of this to seconds or to + + align:start position:0% +conversion of this to seconds or to + + + align:start position:0% +conversion of this to seconds or to +quarter notes or to eighth notes or + + align:start position:0% +quarter notes or to eighth notes or + + + align:start position:0% +quarter notes or to eighth notes or +anything like that + + align:start position:0% +anything like that + + + align:start position:0% +anything like that +um but it's very very useful the one um + + align:start position:0% +um but it's very very useful the one um + + + align:start position:0% +um but it's very very useful the one um +thing that you term that you may have + + align:start position:0% +thing that you term that you may have + + + align:start position:0% +thing that you term that you may have +heard of before midi the midi file + + align:start position:0% +heard of before midi the midi file + + + align:start position:0% +heard of before midi the midi file +format the midi things midi tends to + + align:start position:0% +format the midi things midi tends to + + + align:start position:0% +format the midi things midi tends to +measure everything in ticks um there's + + align:start position:0% +measure everything in ticks um there's + + + align:start position:0% +measure everything in ticks um there's +there's some some things are not and + + align:start position:0% +there's some some things are not and + + + align:start position:0% +there's some some things are not and +it's a little bit of a simplification so + + align:start position:0% +it's a little bit of a simplification so + + + align:start position:0% +it's a little bit of a simplification so +ticks end up being sort of ticks per + + align:start position:0% +ticks end up being sort of ticks per + + + align:start position:0% +ticks end up being sort of ticks per +second or ticks per tick per second is a + + align:start position:0% +second or ticks per tick per second is a + + + align:start position:0% +second or ticks per tick per second is a +pretty good one for Tempo and the other + + align:start position:0% +pretty good one for Tempo and the other + + + align:start position:0% +pretty good one for Tempo and the other +one ticks per + + align:start position:0% + + + + align:start position:0% + +per per quarter note comes up quite a + + align:start position:0% +per per quarter note comes up quite a + + + align:start position:0% +per per quarter note comes up quite a +lot + + align:start position:0% +lot + + + align:start position:0% +lot +um + + align:start position:0% +um + + + align:start position:0% +um +intriguingly because of the problem of + + align:start position:0% +intriguingly because of the problem of + + + align:start position:0% +intriguingly because of the problem of +68 and 5'8 and these weird things um + + align:start position:0% +68 and 5'8 and these weird things um + + + align:start position:0% +68 and 5'8 and these weird things um +measure fundamental measurements in + + align:start position:0% +measure fundamental measurements in + + + align:start position:0% +measure fundamental measurements in +terms of Beats have not primarily been + + align:start position:0% +terms of Beats have not primarily been + + + align:start position:0% +terms of Beats have not primarily been +taken on by um by comp by people who do + + align:start position:0% +taken on by um by comp by people who do + + + align:start position:0% +taken on by um by comp by people who do +um musical representation it's generally + + align:start position:0% +um musical representation it's generally + + + align:start position:0% +um musical representation it's generally +seen as a slightly higher representation + + align:start position:0% +seen as a slightly higher representation + + + align:start position:0% +seen as a slightly higher representation +which is ironic because it's one of our + + align:start position:0% +which is ironic because it's one of our + + + align:start position:0% +which is ironic because it's one of our +fundamental ones for as musicians right + + align:start position:0% +fundamental ones for as musicians right + + + align:start position:0% +fundamental ones for as musicians right +me you think of that oh that lasts half + + align:start position:0% +me you think of that oh that lasts half + + + align:start position:0% +me you think of that oh that lasts half +note it lasts two beats right and then + + align:start position:0% +note it lasts two beats right and then + + + align:start position:0% +note it lasts two beats right and then +somebody reminds you oh what about cut + + align:start position:0% +somebody reminds you oh what about cut + + + align:start position:0% +somebody reminds you oh what about cut +timeing like uh you ruin everything + + align:start position:0% +timeing like uh you ruin everything + + + align:start position:0% +timeing like uh you ruin everything +right you know because we generally do + + align:start position:0% +right you know because we generally do + + + align:start position:0% +right you know because we generally do +some things like this + + align:start position:0% +some things like this + + + align:start position:0% +some things like this +um I will share now what um I ended up + + align:start position:0% +um I will share now what um I ended up + + + align:start position:0% +um I will share now what um I ended up +in my program in music 21 deciding + + align:start position:0% +in my program in music 21 deciding + + + align:start position:0% +in my program in music 21 deciding +that for some reason the quarter + + align:start position:0% +that for some reason the quarter + + + align:start position:0% +that for some reason the quarter +note is the fundamental measure of + + align:start position:0% +note is the fundamental measure of + + + align:start position:0% +note is the fundamental measure of +everything else so that um everything + + align:start position:0% +everything else so that um everything + + + align:start position:0% +everything else so that um everything +send to get measured in quarter + + align:start position:0% +send to get measured in quarter + + + align:start position:0% +send to get measured in quarter +lengths which is a terrible term boy I + + align:start position:0% +lengths which is a terrible term boy I + + + align:start position:0% +lengths which is a terrible term boy I +wish I had come up with something better + + align:start position:0% +wish I had come up with something better + + + align:start position:0% +wish I had come up with something better +uh Essence that's almonds I wish I had + + align:start position:0% +uh Essence that's almonds I wish I had + + + align:start position:0% +uh Essence that's almonds I wish I had +measured in Almond because quarter + + align:start position:0% +measured in Almond because quarter + + + align:start position:0% +measured in Almond because quarter +length takes a very long time to type + + align:start position:0% +length takes a very long time to type + + + align:start position:0% +length takes a very long time to type +with the camel case in the middle um and + + align:start position:0% +with the camel case in the middle um and + + + align:start position:0% +with the camel case in the middle um and +and we didn't have uh what is it get + + align:start position:0% +and we didn't have uh what is it get + + + align:start position:0% +and we didn't have uh what is it get +GitHub autopilot and things like that um + + align:start position:0% +GitHub autopilot and things like that um + + + align:start position:0% +GitHub autopilot and things like that um +um yeah by the way I didn't mean to put + + align:start position:0% +um yeah by the way I didn't mean to put + + + align:start position:0% +um yeah by the way I didn't mean to put +um no chat GPT on the syllabus I put it + + align:start position:0% +um no chat GPT on the syllabus I put it + + + align:start position:0% +um no chat GPT on the syllabus I put it +on uh the thing later today you have fun + + align:start position:0% +on uh the thing later today you have fun + + + align:start position:0% +on uh the thing later today you have fun +with it but not when we're doing any + + align:start position:0% +with it but not when we're doing any + + + align:start position:0% +with it but not when we're doing any +sort of um writing your essay or + + align:start position:0% +sort of um writing your essay or + + + align:start position:0% +sort of um writing your essay or +anything like that but we maybe we'll + + align:start position:0% +anything like that but we maybe we'll + + + align:start position:0% +anything like that but we maybe we'll +come up with a music a chat music or + + align:start position:0% +come up with a music a chat music or + + + align:start position:0% +come up with a music a chat music or +something later on the semester and try + + align:start position:0% +something later on the semester and try + + + align:start position:0% +something later on the semester and try +to see how we can um do things like that + + align:start position:0% +to see how we can um do things like that + + + align:start position:0% +to see how we can um do things like that +but yeah uh I wish I had come up with a + + align:start position:0% +but yeah uh I wish I had come up with a + + + align:start position:0% +but yeah uh I wish I had come up with a +better thing but almost everything + + align:start position:0% +better thing but almost everything + + + align:start position:0% +better thing but almost everything +measured in quarter lengths what's nice + + align:start position:0% +measured in quarter lengths what's nice + + + align:start position:0% +measured in quarter lengths what's nice +about that is how many quarter lengths + + align:start position:0% +about that is how many quarter lengths + + + align:start position:0% +about that is how many quarter lengths +is a quarter + + align:start position:0% +is a quarter + + + align:start position:0% +is a quarter +note one one good good good we're all + + align:start position:0% +note one one good good good we're all + + + align:start position:0% +note one one good good good we're all +we're all still awake I know it's Friday + + align:start position:0% +we're all still awake I know it's Friday + + + align:start position:0% +we're all still awake I know it's Friday +late and things but yeah so I don't um + + align:start position:0% +late and things but yeah so I don't um + + + align:start position:0% +late and things but yeah so I don't um +what how many quarter lengths is a + + align:start position:0% +what how many quarter lengths is a + + + align:start position:0% +what how many quarter lengths is a +quarter note in + + align:start position:0% +quarter note in + + + align:start position:0% +quarter note in +68 one one how many quarter lengths is a + + align:start position:0% +68 one one how many quarter lengths is a + + + align:start position:0% +68 one one how many quarter lengths is a +quarter note in algro one so so these + + align:start position:0% +quarter note in algro one so so these + + + align:start position:0% +quarter note in algro one so so these +things but then how many seconds is + + align:start position:0% +things but then how many seconds is + + + align:start position:0% +things but then how many seconds is +something that's 1.5 quarter lengths ah + + align:start position:0% +something that's 1.5 quarter lengths ah + + + align:start position:0% +something that's 1.5 quarter lengths ah +now you have to keep up with everything + + align:start position:0% +now you have to keep up with everything + + + align:start position:0% +now you have to keep up with everything +so you can kind of think about when + + align:start position:0% +so you can kind of think about when + + + align:start position:0% +so you can kind of think about when +you're thinking about now let's get to + + align:start position:0% +you're thinking about now let's get to + + + align:start position:0% +you're thinking about now let's get to +the first word in this class it's not + + align:start position:0% +the first word in this class it's not + + + align:start position:0% +the first word in this class it's not +representational music theory it's + + align:start position:0% +representational music theory it's + + + align:start position:0% +representational music theory it's +computational when you're starting to + + align:start position:0% +computational when you're starting to + + + align:start position:0% +computational when you're starting to +think + + align:start position:0% + + + + align:start position:0% + +about I'll abbreviate it quite often as + + align:start position:0% +about I'll abbreviate it quite often as + + + align:start position:0% +about I'll abbreviate it quite often as +Q L um + + align:start position:0% +Q L um + + + align:start position:0% +Q L um +to + + align:start position:0% + + + + align:start position:0% + +SEC and maybe we'll say sex are floats + + align:start position:0% +SEC and maybe we'll say sex are floats + + + align:start position:0% +SEC and maybe we'll say sex are floats +in this case + + align:start position:0% +in this case + + + align:start position:0% +in this case +case uh I've use a lot of typed python + + align:start position:0% +case uh I've use a lot of typed python + + + align:start position:0% +case uh I've use a lot of typed python +by the way where if you haven't ever + + align:start position:0% +by the way where if you haven't ever + + + align:start position:0% +by the way where if you haven't ever +seen this um you'll put put this in to + + align:start position:0% +seen this um you'll put put this in to + + + align:start position:0% +seen this um you'll put put this in to +say what I expect to do so it's sort of + + align:start position:0% +say what I expect to do so it's sort of + + + align:start position:0% +say what I expect to do so it's sort of +you know the uh you know all the all the + + align:start position:0% +you know the uh you know all the all the + + + align:start position:0% +you know the uh you know all the all the +um all the joys of having to type more + + align:start position:0% +um all the joys of having to type more + + + align:start position:0% +um all the joys of having to type more +things without type safety um it's not + + align:start position:0% +things without type safety um it's not + + + align:start position:0% +things without type safety um it's not +so good but what do we want to put in as + + align:start position:0% +so good but what do we want to put in as + + + align:start position:0% +so good but what do we want to put in as +our attribute or attributes here we're + + align:start position:0% +our attribute or attributes here we're + + + align:start position:0% +our attribute or attributes here we're +going to return a + + align:start position:0% +going to return a + + + align:start position:0% +going to return a +float what's the first thing that we + + align:start position:0% +float what's the first thing that we + + + align:start position:0% +float what's the first thing that we +that we need ql to + + align:start position:0% +that we need ql to + + + align:start position:0% +that we need ql to +seconds many how many qls yeah so maybe + + align:start position:0% +seconds many how many qls yeah so maybe + + + align:start position:0% +seconds many how many qls yeah so maybe +it'll be ql some people like to do ql in + + align:start position:0% +it'll be ql some people like to do ql in + + + align:start position:0% +it'll be ql some people like to do ql in +and that's going to be measured in what + + align:start position:0% +and that's going to be measured in what + + + align:start position:0% +and that's going to be measured in what +do we want to make + + align:start position:0% +do we want to make + + + align:start position:0% +do we want to make +that + + align:start position:0% +that + + + align:start position:0% +that +float good could be a float in probably + + align:start position:0% +float good could be a float in probably + + + align:start position:0% +float good could be a float in probably +not good enough name something not + + align:start position:0% +not good enough name something not + + + align:start position:0% +not good enough name something not +representational um as an INT in in + + align:start position:0% +representational um as an INT in in + + + align:start position:0% +representational um as an INT in in +quarter lengths eighth note good good um + + align:start position:0% +quarter lengths eighth note good good um + + + align:start position:0% +quarter lengths eighth note good good um +the issue I tend to sometimes use the + + align:start position:0% +the issue I tend to sometimes use the + + + align:start position:0% +the issue I tend to sometimes use the +fraction class if you haven't ever done + + align:start position:0% +fraction class if you haven't ever done + + + align:start position:0% +fraction class if you haven't ever done +that because uh the first time they had + + align:start position:0% +that because uh the first time they had + + + align:start position:0% +that because uh the first time they had +three uh triplets add up actually + + align:start position:0% +three uh triplets add up actually + + + align:start position:0% +three uh triplets add up actually +triplets work fine five quintuplets adds + + align:start position:0% +triplets work fine five quintuplets adds + + + align:start position:0% +triplets work fine five quintuplets adds +up to + + align:start position:0% + + + + align:start position:0% + +1.1 uh quarter notes that's um why I + + align:start position:0% +1.1 uh quarter notes that's um why I + + + align:start position:0% +1.1 uh quarter notes that's um why I +started moving that but floats pretty + + align:start position:0% +started moving that but floats pretty + + + align:start position:0% +started moving that but floats pretty +good good what so that's attribute one + + align:start position:0% +good good what so that's attribute one + + + align:start position:0% +good good what so that's attribute one +is that anybody want another attribute + + align:start position:0% +is that anybody want another attribute + + + align:start position:0% +is that anybody want another attribute +in there + + align:start position:0% + + + + align:start position:0% + +qu length seconds yes the Tempo Tempo + + align:start position:0% +qu length seconds yes the Tempo Tempo + + + align:start position:0% +qu length seconds yes the Tempo Tempo +good so we can define a Tempo object and + + align:start position:0% +good so we can define a Tempo object and + + + align:start position:0% +good so we can define a Tempo object and +now we're going to see um or struct or + + align:start position:0% +now we're going to see um or struct or + + + align:start position:0% +now we're going to see um or struct or +some some kind of a thing well Temple + + align:start position:0% +some some kind of a thing well Temple + + + align:start position:0% +some some kind of a thing well Temple +could be a a basic thing it could be a + + align:start position:0% +could be a a basic thing it could be a + + + align:start position:0% +could be a a basic thing it could be a +float right what else could it + + align:start position:0% + + + + align:start position:0% + +be what do we if we're not thinking + + align:start position:0% +be what do we if we're not thinking + + + align:start position:0% +be what do we if we're not thinking +about algro monopo as used by handle as + + align:start position:0% +about algro monopo as used by handle as + + + align:start position:0% +about algro monopo as used by handle as +opposed to uh mlon or something like + + align:start position:0% +opposed to uh mlon or something like + + + align:start position:0% +opposed to uh mlon or something like +that what do we + + align:start position:0% +that what do we + + + align:start position:0% +that what do we +yeah beats per minute beats per minute + + align:start position:0% +yeah beats per minute beats per minute + + + align:start position:0% +yeah beats per minute beats per minute +okay so we have beats per minute that's + + align:start position:0% +okay so we have beats per minute that's + + + align:start position:0% +okay so we have beats per minute that's +the most common one right so that's + + align:start position:0% +the most common one right so that's + + + align:start position:0% +the most common one right so that's +going to be what do how do you measure + + align:start position:0% +going to be what do how do you measure + + + align:start position:0% +going to be what do how do you measure +beats per + + align:start position:0% + + + + align:start position:0% + +minute oh sorry sorry what what how do + + align:start position:0% +minute oh sorry sorry what what how do + + + align:start position:0% +minute oh sorry sorry what what how do +we want to represent it float + + align:start position:0% +we want to represent it float + + + align:start position:0% +we want to represent it float +good + + align:start position:0% +good + + + align:start position:0% +good +so we passed in first thing a quarter + + align:start position:0% +so we passed in first thing a quarter + + + align:start position:0% +so we passed in first thing a quarter +length second thing a Tempo um is that + + align:start position:0% +length second thing a Tempo um is that + + + align:start position:0% +length second thing a Tempo um is that +enough + + align:start position:0% +enough + + + align:start position:0% +enough +why not time signature time signature in + + align:start position:0% +why not time signature time signature in + + + align:start position:0% +why not time signature time signature in +order to Define what what are we + + align:start position:0% +order to Define what what are we + + + align:start position:0% +order to Define what what are we +defining by the time signature how many + + align:start position:0% +defining by the time signature how many + + + align:start position:0% +defining by the time signature how many +beats in quarter length is great beats + + align:start position:0% +beats in quarter length is great beats + + + align:start position:0% +beats in quarter length is great beats +per quarter + + align:start position:0% +per quarter + + + align:start position:0% +per quarter +length so TS will measure in beats per + + align:start position:0% +length so TS will measure in beats per + + + align:start position:0% +length so TS will measure in beats per +quarter + + align:start position:0% +quarter + + + align:start position:0% +quarter +length and what do we want to make that + + align:start position:0% + + + + align:start position:0% + +also float + + align:start position:0% +also float + + + align:start position:0% +also float +good let's let's do this you don't need + + align:start position:0% +good let's let's do this you don't need + + + align:start position:0% +good let's let's do this you don't need +any sort of go ahead grab laptops let's + + align:start position:0% +any sort of go ahead grab laptops let's + + + align:start position:0% +any sort of go ahead grab laptops let's +Implement quarter length to + + align:start position:0% +Implement quarter length to + + + align:start position:0% +Implement quarter length to +Second let's do it as paired programming + + align:start position:0% +Second let's do it as paired programming + + + align:start position:0% +Second let's do it as paired programming +so we learn from each other so um the + + align:start position:0% +so we learn from each other so um the + + + align:start position:0% +so we learn from each other so um the +person on the left is the who who's done + + align:start position:0% +person on the left is the who who's done + + + align:start position:0% +person on the left is the who who's done +paired programming person on the left is + + align:start position:0% +paired programming person on the left is + + + align:start position:0% +paired programming person on the left is +the driver unless unless the person on + + align:start position:0% +the driver unless unless the person on + + + align:start position:0% +the driver unless unless the person on +the left doesn't have the thing and + + align:start position:0% +the left doesn't have the thing and + + + align:start position:0% +the left doesn't have the thing and +that's your your left not my left um and + + align:start position:0% +that's your your left not my left um and + + + align:start position:0% +that's your your left not my left um and +everybody else will that it's 4:34 will + + align:start position:0% +everybody else will that it's 4:34 will + + + align:start position:0% +everybody else will that it's 4:34 will +take about 10 + + align:start position:0% + + + + align:start position:0% + +minutes okay just just just before we we + + align:start position:0% +minutes okay just just just before we we + + + align:start position:0% +minutes okay just just just before we we +continue and start going on things how + + align:start position:0% +continue and start going on things how + + + align:start position:0% +continue and start going on things how +many people wrote five test cases before + + align:start position:0% +many people wrote five test cases before + + + align:start position:0% +many people wrote five test cases before +you started how many people wrote 10 + + align:start position:0% +you started how many people wrote 10 + + + align:start position:0% +you started how many people wrote 10 +test cases how many people wrote one + + align:start position:0% +test cases how many people wrote one + + + align:start position:0% +test cases how many people wrote one +test case one test case how many people + + align:start position:0% +test case one test case how many people + + + align:start position:0% +test case one test case how many people +wrote zero test cases okay this is + + align:start position:0% +wrote zero test cases okay this is + + + align:start position:0% +wrote zero test cases okay this is +you're going to hear this a couple times + + align:start position:0% +you're going to hear this a couple times + + + align:start position:0% +you're going to hear this a couple times +the next class and stuff and this is + + align:start position:0% +the next class and stuff and this is + + + align:start position:0% +the next class and stuff and this is +very different guys just one second you + + align:start position:0% +very different guys just one second you + + + align:start position:0% +very different guys just one second you +get back into it very different from a + + align:start position:0% +get back into it very different from a + + + align:start position:0% +get back into it very different from a +lot of the especially intro level CS + + align:start position:0% +lot of the especially intro level CS + + + align:start position:0% +lot of the especially intro level CS +class at MIT but because this isn't a + + align:start position:0% +class at MIT but because this isn't a + + + align:start position:0% +class at MIT but because this isn't a +really big established field I I I told + + align:start position:0% +really big established field I I I told + + + align:start position:0% +really big established field I I I told +all yall that you're really you this one + + align:start position:0% +all yall that you're really you this one + + + align:start position:0% +all yall that you're really you this one +of the very few classes like this right + + align:start position:0% +of the very few classes like this right + + + align:start position:0% +of the very few classes like this right +one of the really important things is + + align:start position:0% +one of the really important things is + + + align:start position:0% +one of the really important things is +writing test cases and especially + + align:start position:0% +writing test cases and especially + + + align:start position:0% +writing test cases and especially +looking at corner cases so get in the + + align:start position:0% +looking at corner cases so get in the + + + align:start position:0% +looking at corner cases so get in the +habit of this you're going to if I'm + + align:start position:0% +habit of this you're going to if I'm + + + align:start position:0% +habit of this you're going to if I'm +feeling nice I might give one or to test + + align:start position:0% +feeling nice I might give one or to test + + + align:start position:0% +feeling nice I might give one or to test +cases with correct answers on things but + + align:start position:0% +cases with correct answers on things but + + + align:start position:0% +cases with correct answers on things but +a lot of it is sit down and think at 60 + + align:start position:0% +a lot of it is sit down and think at 60 + + + align:start position:0% +a lot of it is sit down and think at 60 +beats per minute at um 44 how many how + + align:start position:0% +beats per minute at um 44 how many how + + + align:start position:0% +beats per minute at um 44 how many how +long what's the answer for a quarter + + align:start position:0% +long what's the answer for a quarter + + + align:start position:0% +long what's the answer for a quarter +note for + + align:start position:0% +note for + + + align:start position:0% +note for +one one good least make sure your code + + align:start position:0% +one one good least make sure your code + + + align:start position:0% +one one good least make sure your code +does that before we go on so keep going + + align:start position:0% +does that before we go on so keep going + + + align:start position:0% +does that before we go on so keep going +try try some running and try + + align:start position:0% + + + + align:start position:0% + +some okay let's let's all come back + + align:start position:0% +some okay let's let's all come back + + + align:start position:0% +some okay let's let's all come back +together for a bit because this this + + align:start position:0% +together for a bit because this this + + + align:start position:0% +together for a bit because this this +isn't the problem set and I want to want + + align:start position:0% +isn't the problem set and I want to want + + + align:start position:0% +isn't the problem set and I want to want +to kind of move on and things + + align:start position:0% +to kind of move on and things + + + align:start position:0% +to kind of move on and things +what one of the terms I heard a lot um + + align:start position:0% +what one of the terms I heard a lot um + + + align:start position:0% +what one of the terms I heard a lot um +for uh was this one let's do a + + align:start position:0% +for uh was this one let's do a + + + align:start position:0% +for uh was this one let's do a +dimensional analysis or things like that + + align:start position:0% +dimensional analysis or things like that + + + align:start position:0% +dimensional analysis or things like that +for somebody who didn't use that term or + + align:start position:0% +for somebody who didn't use that term or + + + align:start position:0% +for somebody who didn't use that term or +who doesn't we're all coming from + + align:start position:0% +who doesn't we're all coming from + + + align:start position:0% +who doesn't we're all coming from +different backgrounds and things what's + + align:start position:0% +different backgrounds and things what's + + + align:start position:0% +different backgrounds and things what's +a dimensional analysis sto geometry + + align:start position:0% +a dimensional analysis sto geometry + + + align:start position:0% +a dimensional analysis sto geometry +story geometry well thank you for + + align:start position:0% +story geometry well thank you for + + + align:start position:0% +story geometry well thank you for +obviously skating for + + align:start position:0% +obviously skating for + + + align:start position:0% +obviously skating for +there uh we'll get you other the called + + align:start position:0% +there uh we'll get you other the called + + + align:start position:0% +there uh we'll get you other the called +what's that called stochiometry + + align:start position:0% +what's that called stochiometry + + + align:start position:0% +what's that called stochiometry +stochiometry I i' I have I I must have + + align:start position:0% +stochiometry I i' I have I I must have + + + align:start position:0% +stochiometry I i' I have I I must have +failed trigonometry so I didn't get to + + align:start position:0% +failed trigonometry so I didn't get to + + + align:start position:0% +failed trigonometry so I didn't get to +that one what what is + + align:start position:0% +that one what what is + + + align:start position:0% +that one what what is +what okay what what what what what what + + align:start position:0% +what okay what what what what what what + + + align:start position:0% +what okay what what what what what what +that mean I honestly I just learned a + + align:start position:0% +that mean I honestly I just learned a + + + align:start position:0% +that mean I honestly I just learned a +new word thank you that's just + + align:start position:0% +new word thank you that's just + + + align:start position:0% +new word thank you that's just +dimensional analysis for chemistry + + align:start position:0% +dimensional analysis for chemistry + + + align:start position:0% +dimensional analysis for chemistry +that's just dimensional analysis for + + align:start position:0% +that's just dimensional analysis for + + + align:start position:0% +that's just dimensional analysis for +chemistry okay good I I we remember I I + + align:start position:0% +chemistry okay good I I we remember I I + + + align:start position:0% +chemistry okay good I I we remember I I +was up the river so we didn't we didn't + + align:start position:0% +was up the river so we didn't we didn't + + + align:start position:0% +was up the river so we didn't we didn't +learn these things um uh what's the um + + align:start position:0% +learn these things um uh what's the um + + + align:start position:0% +learn these things um uh what's the um +what what do we mean when we're talking + + align:start position:0% +what what do we mean when we're talking + + + align:start position:0% +what what do we mean when we're talking +about dimensional analysis yeah it's + + align:start position:0% +about dimensional analysis yeah it's + + + align:start position:0% +about dimensional analysis yeah it's +like a conversion between equivalent + + align:start position:0% +like a conversion between equivalent + + + align:start position:0% +like a conversion between equivalent +units conversion between equivalent + + align:start position:0% +units conversion between equivalent + + + align:start position:0% +units conversion between equivalent +units good what are some of dimensional + + align:start position:0% +units good what are some of dimensional + + + align:start position:0% +units good what are some of dimensional +analysis things you uh you've done + + align:start position:0% +analysis things you uh you've done + + + align:start position:0% +analysis things you uh you've done +before this + + align:start position:0% +before this + + + align:start position:0% +before this +class other things Yeahs physics so so + + align:start position:0% +class other things Yeahs physics so so + + + align:start position:0% +class other things Yeahs physics so so +what's what's a dimension what's kind + + align:start position:0% +what's what's a dimension what's kind + + + align:start position:0% +what's what's a dimension what's kind +try convert like um where Str is like + + align:start position:0% +try convert like um where Str is like + + + align:start position:0% +try convert like um where Str is like +meters per second like miles per hour + + align:start position:0% +meters per second like miles per hour + + + align:start position:0% +meters per second like miles per hour +great meters per second to miles per + + align:start position:0% +great meters per second to miles per + + + align:start position:0% +great meters per second to miles per +hour and absolutely thank thank you so + + align:start position:0% +hour and absolutely thank thank you so + + + align:start position:0% +hour and absolutely thank thank you so +we have the particular conversion there + + align:start position:0% +we have the particular conversion there + + + align:start position:0% +we have the particular conversion there +so we have meters seconds miles hours + + align:start position:0% +so we have meters seconds miles hours + + + align:start position:0% +so we have meters seconds miles hours +what what were some dimensionality + + align:start position:0% +what what were some dimensionality + + + align:start position:0% +what what were some dimensionality +things uh uh Dimensions that that you + + align:start position:0% +things uh uh Dimensions that that you + + + align:start position:0% +things uh uh Dimensions that that you +use now that you might not have used in + + align:start position:0% +use now that you might not have used in + + + align:start position:0% +use now that you might not have used in +your past + + align:start position:0% +your past + + + align:start position:0% +your past +before yeah beats quarter lengths beats + + align:start position:0% +before yeah beats quarter lengths beats + + + align:start position:0% +before yeah beats quarter lengths beats +per quarter length it beats quarter L + + align:start position:0% +per quarter length it beats quarter L + + + align:start position:0% +per quarter length it beats quarter L +quarter length per beat good beats + + align:start position:0% +quarter length per beat good beats + + + align:start position:0% +quarter length per beat good beats +quarter lengths absolutely um you've + + align:start position:0% +quarter lengths absolutely um you've + + + align:start position:0% +quarter lengths absolutely um you've +probably done heard beats per minute not + + align:start position:0% +probably done heard beats per minute not + + + align:start position:0% +probably done heard beats per minute not +everybody has thought of it as okay then + + align:start position:0% +everybody has thought of it as okay then + + + align:start position:0% +everybody has thought of it as okay then +I have to convert to um beats + + align:start position:0% +I have to convert to um beats + + + align:start position:0% +I have to convert to um beats +per beats per second which is not + + align:start position:0% +per beats per second which is not + + + align:start position:0% +per beats per second which is not +something we think about we're very very + + align:start position:0% +something we think about we're very very + + + align:start position:0% +something we think about we're very very +good at think about beats per minute as + + align:start position:0% +good at think about beats per minute as + + + align:start position:0% +good at think about beats per minute as +musicians we're very very bad at think + + align:start position:0% +musicians we're very very bad at think + + + align:start position:0% +musicians we're very very bad at think +about beats per second or seconds per + + align:start position:0% +about beats per second or seconds per + + + align:start position:0% +about beats per second or seconds per +beat and then beats per what was the + + align:start position:0% +beat and then beats per what was the + + + align:start position:0% +beat and then beats per what was the +other thing beats per quarter + + align:start position:0% +other thing beats per quarter + + + align:start position:0% +other thing beats per quarter +length awesome so that came up quite a + + align:start position:0% +length awesome so that came up quite a + + + align:start position:0% +length awesome so that came up quite a +bit on on things going on what were some + + align:start position:0% +bit on on things going on what were some + + + align:start position:0% +bit on on things going on what were some +other things that seemed to um stump or + + align:start position:0% +other things that seemed to um stump or + + + align:start position:0% +other things that seemed to um stump or +be be fun or interesting or that you + + align:start position:0% +be be fun or interesting or that you + + + align:start position:0% +be be fun or interesting or that you +learned from programming this I heard a + + align:start position:0% +learned from programming this I heard a + + + align:start position:0% +learned from programming this I heard a +lot of we don't need the time signature + + align:start position:0% +lot of we don't need the time signature + + + align:start position:0% +lot of we don't need the time signature +I think I think I heard that aloud at + + align:start position:0% +I think I think I heard that aloud at + + + align:start position:0% +I think I think I heard that aloud at +least three or four times so but what do + + align:start position:0% +least three or four times so but what do + + + align:start position:0% +least three or four times so but what do +you do if you have the time signature + + align:start position:0% +you do if you have the time signature + + + align:start position:0% +you do if you have the time signature +and the problem let's say we're leaving + + align:start position:0% +and the problem let's say we're leaving + + + align:start position:0% +and the problem let's say we're leaving +out that 5'8 where the beat changes + + align:start position:0% +out that 5'8 where the beat changes + + + align:start position:0% +out that 5'8 where the beat changes +stuff how do we convert from um time + + align:start position:0% +stuff how do we convert from um time + + + align:start position:0% +stuff how do we convert from um time +signature let's let's think of time + + align:start position:0% +signature let's let's think of time + + + align:start position:0% +signature let's let's think of time +signature first as a struct as a as a + + align:start position:0% +signature first as a struct as a as a + + + align:start position:0% +signature first as a struct as a as a +two Tuple of numerator and + + align:start position:0% + + + + align:start position:0% + +denominator how do you convert a + + align:start position:0% +denominator how do you convert a + + + align:start position:0% +denominator how do you convert a +numerator to denominator into um beats + + align:start position:0% +numerator to denominator into um beats + + + align:start position:0% +numerator to denominator into um beats +per quarter + + align:start position:0% + + + + align:start position:0% + +length what is 44 how many beats per + + align:start position:0% +length what is 44 how many beats per + + + align:start position:0% +length what is 44 how many beats per +quarter + + align:start position:0% + + + + align:start position:0% + +length good what is uh + + align:start position:0% + + + + align:start position:0% + +22 how many + + align:start position:0% +22 how many + + + align:start position:0% +22 how many +beats oh good I I did I did hear it but + + align:start position:0% +beats oh good I I did I did hear it but + + + align:start position:0% +beats oh good I I did I did hear it but +I heard a lot of I love it this is this + + align:start position:0% +I heard a lot of I love it this is this + + + align:start position:0% +I heard a lot of I love it this is this +is why I'm hoping to get to his class I + + align:start position:0% +is why I'm hoping to get to his class I + + + align:start position:0% +is why I'm hoping to get to his class I +heard a lot of very loud wrong answers + + align:start position:0% +heard a lot of very loud wrong answers + + + align:start position:0% +heard a lot of very loud wrong answers +and then very very trickling right at + + align:start position:0% +and then very very trickling right at + + + align:start position:0% +and then very very trickling right at +the end of little whispered right answer + + align:start position:0% +the end of little whispered right answer + + + align:start position:0% +the end of little whispered right answer +uh how many how many beats per quarter + + align:start position:0% +uh how many how many beats per quarter + + + align:start position:0% +uh how many how many beats per quarter +length for cut time for two + + align:start position:0% +length for cut time for two + + + align:start position:0% +length for cut time for two +two two two and I also heard + + align:start position:0% +two two two and I also heard + + + align:start position:0% +two two two and I also heard +whispered somebody had + + align:start position:0% + + + + align:start position:0% + +1 12 how many beats does it take to play + + align:start position:0% +1 12 how many beats does it take to play + + + align:start position:0% +1 12 how many beats does it take to play +a quarter note in 2 + + align:start position:0% + + + + align:start position:0% + +two how long does each of these is that + + align:start position:0% +two how long does each of these is that + + + align:start position:0% +two how long does each of these is that +correct am I wrong this + + align:start position:0% +correct am I wrong this + + + align:start position:0% +correct am I wrong this +time half a beat this is half a beat and + + align:start position:0% +time half a beat this is half a beat and + + + align:start position:0% +time half a beat this is half a beat and +it gets a quarter note this is half a + + align:start position:0% +it gets a quarter note this is half a + + + align:start position:0% +it gets a quarter note this is half a +beat and it gets a quarter note okay + + align:start position:0% +beat and it gets a quarter note okay + + + align:start position:0% +beat and it gets a quarter note okay +what about in + + align:start position:0% + + + + align:start position:0% + +32 half 1 half so what do what part do + + align:start position:0% +32 half 1 half so what do what part do + + + align:start position:0% +32 half 1 half so what do what part do +we not need + + align:start position:0% +we not need + + + align:start position:0% +we not need +need + + align:start position:0% +need + + + align:start position:0% +need +numerator so for this particular thing + + align:start position:0% +numerator so for this particular thing + + + align:start position:0% +numerator so for this particular thing +we don't need the numerator we would if + + align:start position:0% +we don't need the numerator we would if + + + align:start position:0% +we don't need the numerator we would if +we yeah go ahead Matthew don't we need + + align:start position:0% +we yeah go ahead Matthew don't we need + + + align:start position:0% +we yeah go ahead Matthew don't we need +the numerator in 68 do we need the + + align:start position:0% +the numerator in 68 do we need the + + + align:start position:0% +the numerator in 68 do we need the +numerator in 68 yes so what do we need + + align:start position:0% +numerator in 68 yes so what do we need + + + align:start position:0% +numerator in 68 yes so what do we need +the numerator + + align:start position:0% + + + + align:start position:0% + +four we only need the numerator to do a + + align:start position:0% +four we only need the numerator to do a + + + align:start position:0% +four we only need the numerator to do a +modulo + + align:start position:0% +modulo + + + align:start position:0% +modulo +operation to see compare if it equal Z + + align:start position:0% +operation to see compare if it equal Z + + + align:start position:0% +operation to see compare if it equal Z +but is that good enough because because + + align:start position:0% +but is that good enough because because + + + align:start position:0% +but is that good enough because because +68 98 128 these all generally default in + + align:start position:0% +68 98 128 these all generally default in + + + align:start position:0% +68 98 128 these all generally default in +most conceptions not all but in most + + align:start position:0% +most conceptions not all but in most + + + align:start position:0% +most conceptions not all but in most +conceptions as the the number of Beats + + align:start position:0% +conceptions as the the number of Beats + + + align:start position:0% +conceptions as the the number of Beats +is divided by three on that so is that + + align:start position:0% +is divided by three on that so is that + + + align:start position:0% +is divided by three on that so is that +good enough does everyone know modulo + + align:start position:0% +good enough does everyone know modulo + + + align:start position:0% +good enough does everyone know modulo +notation like the remainder when divided + + align:start position:0% +notation like the remainder when divided + + + align:start position:0% +notation like the remainder when divided +by three equals zero so does that work + + align:start position:0% +by three equals zero so does that work + + + align:start position:0% +by three equals zero so does that work +68 great uh 88 nope that's a normal one + + align:start position:0% +68 great uh 88 nope that's a normal one + + + align:start position:0% +68 great uh 88 nope that's a normal one +98 great + + align:start position:0% + + + + align:start position:0% + +so 64 great that six how many beats does + + align:start position:0% +so 64 great that six how many beats does + + + align:start position:0% +so 64 great that six how many beats does + + align:start position:0% + + + + align:start position:0% + +have in in treated in this in this + + align:start position:0% +have in in treated in this in this + + + align:start position:0% +have in in treated in this in this +way two two one two one dot dot two dot + + align:start position:0% +way two two one two one dot dot two dot + + + align:start position:0% +way two two one two one dot dot two dot +dot yeah I say it has two in I one two + + align:start position:0% +dot yeah I say it has two in I one two + + + align:start position:0% +dot yeah I say it has two in I one two +three four but I I'm giving you the big + + align:start position:0% +three four but I I'm giving you the big + + + align:start position:0% +three four but I I'm giving you the big +one great so six 64 How many does 916 + + align:start position:0% +one great so six 64 How many does 916 + + + align:start position:0% +one great so six 64 How many does 916 +have three three great so this this + + align:start position:0% +have three three great so this this + + + align:start position:0% +have three three great so this this +works right we've we we have all our + + align:start position:0% +works right we've we we have all our + + + align:start position:0% +works right we've we we have all our +good test cases + + align:start position:0% +good test cases + + + align:start position:0% +good test cases +there yeah you're smiling big anyone + + align:start position:0% +there yeah you're smiling big anyone + + + align:start position:0% +there yeah you're smiling big anyone +else smiling big you're smiling big what + + align:start position:0% +else smiling big you're smiling big what + + + align:start position:0% +else smiling big you're smiling big what +what's the test case we've missed 34 + + align:start position:0% +what's the test case we've missed 34 + + + align:start position:0% +what's the test case we've missed 34 +34 so 34 has one + + align:start position:0% +34 so 34 has one + + + align:start position:0% +34 so 34 has one +beat right because you divide by three + + align:start position:0% +beat right because you divide by three + + + align:start position:0% +beat right because you divide by three +so what what do we have to + + align:start position:0% + + + + align:start position:0% + +do this if the numerator modu 3 equals + + align:start position:0% +do this if the numerator modu 3 equals + + + align:start position:0% +do this if the numerator modu 3 equals +0 and + + align:start position:0% + + + + align:start position:0% + +num not equals + + align:start position:0% +num not equals + + + align:start position:0% +num not equals + + align:start position:0% + + + align:start position:0% +right that's assuming we've already done + + align:start position:0% +right that's assuming we've already done + + + align:start position:0% +right that's assuming we've already done +our assertion that n numerator is + + align:start position:0% +our assertion that n numerator is + + + align:start position:0% +our assertion that n numerator is +positive and all the other things right + + align:start position:0% +positive and all the other things right + + + align:start position:0% +positive and all the other things right +so these are the algorithms that you + + align:start position:0% +so these are the algorithms that you + + + align:start position:0% +so these are the algorithms that you +already know in your head for music by + + align:start position:0% +already know in your head for music by + + + align:start position:0% +already know in your head for music by +being musicians but they are not the + + align:start position:0% +being musicians but they are not the + + + align:start position:0% +being musicians but they are not the +algorithms that you have been + + align:start position:0% +algorithms that you have been + + + align:start position:0% +algorithms that you have been +programming before here's a particular + + align:start position:0% +programming before here's a particular + + + align:start position:0% +programming before here's a particular +one that's that I always like to do and + + align:start position:0% +one that's that I always like to do and + + + align:start position:0% +one that's that I always like to do and +I don't think we're going to have time + + align:start position:0% +I don't think we're going to have time + + + align:start position:0% +I don't think we're going to have time +to go through it today because you guys + + align:start position:0% +to go through it today because you guys + + + align:start position:0% +to go through it today because you guys +have been such great participants in my + + align:start position:0% +have been such great participants in my + + + align:start position:0% +have been such great participants in my +um in my terrible uh employees and + + align:start position:0% +um in my terrible uh employees and + + + align:start position:0% +um in my terrible uh employees and +things um given a a note given a quarter + + align:start position:0% +things um given a a note given a quarter + + + align:start position:0% +things um given a a note given a quarter +note let's say we we'll keep it really + + align:start position:0% +note let's say we we'll keep it really + + + align:start position:0% +note let's say we we'll keep it really +simple because we're already in we'll + + align:start position:0% +simple because we're already in we'll + + + align:start position:0% +simple because we're already in we'll +call the quarter note one one quarter L + + align:start position:0% +call the quarter note one one quarter L + + + align:start position:0% +call the quarter note one one quarter L +one beat or + + align:start position:0% +one beat or + + + align:start position:0% +one beat or +something given a DOT how many + + align:start position:0% +something given a DOT how many + + + align:start position:0% +something given a DOT how many +beats 1.5 given two + + align:start position:0% + + + + align:start position:0% + +dots three + + align:start position:0% +dots three + + + align:start position:0% +dots three +dots oh somebody had is Trail off good + + align:start position:0% +dots oh somebody had is Trail off good + + + align:start position:0% +dots oh somebody had is Trail off good +end + + align:start position:0% +end + + + align:start position:0% +end +dots what is the + + align:start position:0% + + + + align:start position:0% + +formula yeah so so working this out and + + align:start position:0% +formula yeah so so working this out and + + + align:start position:0% +formula yeah so so working this out and +if you want I'll put a link online uh + + align:start position:0% +if you want I'll put a link online uh + + + align:start position:0% +if you want I'll put a link online uh +once I originally had to write out this + + align:start position:0% +once I originally had to write out this + + + align:start position:0% +once I originally had to write out this +formula because I kind of needed it it + + align:start position:0% +formula because I kind of needed it it + + + align:start position:0% +formula because I kind of needed it it +becomes kind of fun so um yeah so it and + + align:start position:0% +becomes kind of fun so um yeah so it and + + + align:start position:0% +becomes kind of fun so um yeah so it and +end up being uh what do you call them + + align:start position:0% +end up being uh what do you call them + + + align:start position:0% +end up being uh what do you call them +these are meren numbers which are not + + align:start position:0% +these are meren numbers which are not + + + align:start position:0% +these are meren numbers which are not +the same as meren primes they end up + + align:start position:0% +the same as meren primes they end up + + + align:start position:0% +the same as meren primes they end up +being um sort of n minus one uh what is + + align:start position:0% +being um sort of n minus one uh what is + + + align:start position:0% +being um sort of n minus one uh what is +it 2 to the N - one over 2 to the N so + + align:start position:0% +it 2 to the N - one over 2 to the N so + + + align:start position:0% +it 2 to the N - one over 2 to the N so +you end up one and one half slightly + + align:start position:0% +you end up one and one half slightly + + + align:start position:0% +you end up one and one half slightly +under one and 3/4 1 and 78 so 2 to the N + + align:start position:0% +under one and 3/4 1 and 78 so 2 to the N + + + align:start position:0% +under one and 3/4 1 and 78 so 2 to the N +whatever so you can to figure out okay + + align:start position:0% +whatever so you can to figure out okay + + + align:start position:0% +whatever so you can to figure out okay +and hopefully that works um two to the + + align:start position:0% +and hopefully that works um two to the + + + align:start position:0% +and hopefully that works um two to the +zero sorry that that goes down below + + align:start position:0% +zero sorry that that goes down below + + + align:start position:0% +zero sorry that that goes down below +that's not part of the exponent I should + + align:start position:0% +that's not part of the exponent I should + + + align:start position:0% +that's not part of the exponent I should +make that nicer 2 to the N minus one + + align:start position:0% +make that nicer 2 to the N minus one + + + align:start position:0% +make that nicer 2 to the N minus one +over 2 to the N sorry I haven't been + + align:start position:0% +over 2 to the N sorry I haven't been + + + align:start position:0% +over 2 to the N sorry I haven't been +writing on whiteboards in a year so My + + align:start position:0% +writing on whiteboards in a year so My + + + align:start position:0% +writing on whiteboards in a year so My +technique is a little low so does that + + align:start position:0% +technique is a little low so does that + + + align:start position:0% +technique is a little low so does that +does that work or one plus right yeah so + + align:start position:0% +does that work or one plus right yeah so + + + align:start position:0% +does that work or one plus right yeah so +uh does that work for zero dots what's + + align:start position:0% +uh does that work for zero dots what's + + + align:start position:0% +uh does that work for zero dots what's +two to the + + align:start position:0% +two to the + + + align:start position:0% +two to the +zeroth what's two to the Zer one one + + align:start position:0% +zeroth what's two to the Zer one one + + + align:start position:0% +zeroth what's two to the Zer one one +minus one is zero so that cancels that + + align:start position:0% +minus one is zero so that cancels that + + + align:start position:0% +minus one is zero so that cancels that +out as long as that's not zero there + + align:start position:0% +out as long as that's not zero there + + + align:start position:0% +out as long as that's not zero there +good so we get one what happens if you + + align:start position:0% +good so we get one what happens if you + + + align:start position:0% +good so we get one what happens if you +have a negative one + + align:start position:0% + + + + align:start position:0% + +dot 2 to the + + align:start position:0% +dot 2 to the + + + align:start position:0% +dot 2 to the +1 12 minus + + align:start position:0% + + + + align:start position:0% + +one2 over two to the um over 2 to + + align:start position:0% +one2 over two to the um over 2 to + + + align:start position:0% +one2 over two to the um over 2 to +thetive + + align:start position:0% +thetive + + + align:start position:0% +thetive +1 over2 and what's that end up2 over2 1 + + align:start position:0% +1 over2 and what's that end up2 over2 1 + + + align:start position:0% +1 over2 and what's that end up2 over2 1 ++ 1 equal zero zero so every time you + + align:start position:0% ++ 1 equal zero zero so every time you + + + align:start position:0% ++ 1 equal zero zero so every time you +don't hear any music no you're hearing + + align:start position:0% +don't hear any music no you're hearing + + + align:start position:0% +don't hear any music no you're hearing +the grand Symphony of negative one + + align:start position:0% + + + + align:start position:0% + +dots I think that's a good place to wrap + + align:start position:0% +dots I think that's a good place to wrap + + + align:start position:0% +dots I think that's a good place to wrap +up \ No newline at end of file diff --git a/KfmQr8gcBL0.txt b/KfmQr8gcBL0.txt new file mode 100644 index 0000000000000000000000000000000000000000..eb9ef8cf9cccbcc5a2e0ab988c975c602aa8c5cc --- /dev/null +++ b/KfmQr8gcBL0.txt @@ -0,0 +1,1323 @@ +align:start position:0% + +I just wanted to tell you a little bit + + align:start position:0% +I just wanted to tell you a little bit + + + align:start position:0% +I just wanted to tell you a little bit +more about grocery shopping in Italy oh + + align:start position:0% +more about grocery shopping in Italy oh + + + align:start position:0% +more about grocery shopping in Italy oh +while we are + + align:start position:0% +while we are + + + align:start position:0% +while we are +waiting yeah we will say cop cop yes + + align:start position:0% + + + + align:start position:0% + +not it's it's a supermarket oh oh yeah + + align:start position:0% +not it's it's a supermarket oh oh yeah + + + align:start position:0% +not it's it's a supermarket oh oh yeah +say say + + align:start position:0% + + + + align:start position:0% + +C okay so do you remember how to say um + + align:start position:0% +C okay so do you remember how to say um + + + align:start position:0% +C okay so do you remember how to say um +I'm going or I go grocery shopping okay + + align:start position:0% +I'm going or I go grocery shopping okay + + + align:start position:0% +I'm going or I go grocery shopping okay +you can say V super okay okay when you + + align:start position:0% +you can say V super okay okay when you + + + align:start position:0% +you can say V super okay okay when you +say I'm I'm I'm getting my groceries + + align:start position:0% +say I'm I'm I'm getting my groceries + + + align:start position:0% +say I'm I'm I'm getting my groceries +usually you + + align:start position:0% + + + + align:start position:0% + +say so it's + + align:start position:0% +say so it's + + + align:start position:0% +say so it's +for so + + align:start position:0% + + + + align:start position:0% + +it's + + align:start position:0% + + + + align:start position:0% + +repat and is an irregular ver very very + + align:start position:0% +repat and is an irregular ver very very + + + align:start position:0% +repat and is an irregular ver very very +difficult + + align:start position:0% +difficult + + + align:start position:0% +difficult +okay so let's try to review it we + + align:start position:0% + + + + align:start position:0% + +say + + align:start position:0% + + + + align:start position:0% + +yes you remember why I'm putting the + + align:start position:0% +yes you remember why I'm putting the + + + align:start position:0% +yes you remember why I'm putting the +subject in parenthesis see because you + + align:start position:0% +subject in parenthesis see because you + + + align:start position:0% +subject in parenthesis see because you +don't usually say yeah we don't usually + + align:start position:0% +don't usually say yeah we don't usually + + + align:start position:0% +don't usually say yeah we don't usually +say unless you really want want to + + align:start position:0% +say unless you really want want to + + + align:start position:0% +say unless you really want want to +emphasize now if you're + + align:start position:0% + + + + align:start position:0% + +upset why don't you + + align:start position:0% +upset why don't you + + + align:start position:0% +upset why don't you +say that's it would be it could be fine + + align:start position:0% +say that's it would be it could be fine + + + align:start position:0% +say that's it would be it could be fine +to + + align:start position:0% +to + + + align:start position:0% +to +say if you really want to emphasize + + align:start position:0% +say if you really want to emphasize + + + align:start position:0% +say if you really want to emphasize +that I am + + align:start position:0% + + + + align:start position:0% + +going which implies not you + + align:start position:0% +going which implies not you + + + align:start position:0% +going which implies not you +okay yeah see wow you remember + + align:start position:0% + + + + align:start position:0% + +everything it's a v no don't ruin the + + align:start position:0% +everything it's a v no don't ruin the + + + align:start position:0% +everything it's a v no don't ruin the +magic come on you have one left it's a + + align:start position:0% +magic come on you have one left it's a + + + align:start position:0% +magic come on you have one left it's a +it has to be with the V it's with a V + + align:start position:0% + + + + align:start position:0% + +yes it's + + align:start position:0% + + + + align:start position:0% + +difficult + + align:start position:0% +difficult + + + align:start position:0% +difficult +like + + align:start position:0% +like + + + align:start position:0% +like +yeah okay so let's try like try to read + + align:start position:0% +yeah okay so let's try like try to read + + + align:start position:0% +yeah okay so let's try like try to read +it + + align:start position:0% + + + + align:start position:0% + +aloud let's do without the subject + + align:start position:0% + + + + align:start position:0% + +just we have different + + align:start position:0% + + + + align:start position:0% + +options + + align:start position:0% +options + + + align:start position:0% +options +super marato is a big grocery store like + + align:start position:0% +super marato is a big grocery store like + + + align:start position:0% +super marato is a big grocery store like +you would find + + align:start position:0% + + + + align:start position:0% + +here super + + align:start position:0% +here super + + + align:start position:0% +here super +super super super good a super or maybe + + align:start position:0% +super super super good a super or maybe + + + align:start position:0% +super super super good a super or maybe +you prefer to do your grocery shopping + + align:start position:0% +you prefer to do your grocery shopping + + + align:start position:0% +you prefer to do your grocery shopping +in smaller shops so you have different + + align:start position:0% +in smaller shops so you have different + + + align:start position:0% +in smaller shops so you have different +options that is yes that is in merato + + align:start position:0% +options that is yes that is in merato + + + align:start position:0% +options that is yes that is in merato +but you know what is in merato like the + + align:start position:0% +but you know what is in merato like the + + + align:start position:0% +but you know what is in merato like the +F yes the difference is that that the + + align:start position:0% +F yes the difference is that that the + + + align:start position:0% +F yes the difference is that that the +farmers market usually you get good + + align:start position:0% +farmers market usually you get good + + + align:start position:0% +farmers market usually you get good +stuff but it's kind of expensive if you + + align:start position:0% +stuff but it's kind of expensive if you + + + align:start position:0% +stuff but it's kind of expensive if you +get if you go on Mercato then usually + + align:start position:0% +get if you go on Mercato then usually + + + align:start position:0% +get if you go on Mercato then usually +it's good stuff and it's not more + + align:start position:0% +it's good stuff and it's not more + + + align:start position:0% +it's good stuff and it's not more +expensive every town or every + + align:start position:0% +expensive every town or every + + + align:start position:0% +expensive every town or every +neighborhood has a day of the week when + + align:start position:0% +neighborhood has a day of the week when + + + align:start position:0% +neighborhood has a day of the week when +there is + + align:start position:0% +there is + + + align:start position:0% +there is +inato for example in my hometown inato + + align:start position:0% +inato for example in my hometown inato + + + align:start position:0% +inato for example in my hometown inato +ATB which day Saturday morning yes + + align:start position:0% +ATB which day Saturday morning yes + + + align:start position:0% +ATB which day Saturday morning yes +usually it's always in the morning so + + align:start position:0% +usually it's always in the morning so + + + align:start position:0% +usually it's always in the morning so +when I go visit I always try to be there + + align:start position:0% +when I go visit I always try to be there + + + align:start position:0% +when I go visit I always try to be there +on Saturday morning cuz I love going + + align:start position:0% +on Saturday morning cuz I love going + + + align:start position:0% +on Saturday morning cuz I love going +there you get the best fruits vegetables + + align:start position:0% +there you get the best fruits vegetables + + + align:start position:0% +there you get the best fruits vegetables +the best cheese + + align:start position:0% +the best cheese + + + align:start position:0% +the best cheese +everything and and you don't find only + + align:start position:0% +everything and and you don't find only + + + align:start position:0% +everything and and you don't find only +food you also find clothes and shoes + + align:start position:0% +food you also find clothes and shoes + + + align:start position:0% +food you also find clothes and shoes +really old kind of some so if you go to + + align:start position:0% +really old kind of some so if you go to + + + align:start position:0% +really old kind of some so if you go to +visit some place in Italy you should + + align:start position:0% +visit some place in Italy you should + + + align:start position:0% +visit some place in Italy you should +check when is in the Catt well then you + + align:start position:0% +check when is in the Catt well then you + + + align:start position:0% +check when is in the Catt well then you +can you have different options there are + + align:start position:0% +can you have different options there are + + + align:start position:0% +can you have different options there are +small shops that sell food and they're + + align:start position:0% +small shops that sell food and they're + + + align:start position:0% +small shops that sell food and they're +called + + align:start position:0% + + + + align:start position:0% + +alimar 1 2 3 element yes El and they + + align:start position:0% +alimar 1 2 3 element yes El and they + + + align:start position:0% +alimar 1 2 3 element yes El and they +tend to be a little bit more expensive + + align:start position:0% +tend to be a little bit more expensive + + + align:start position:0% +tend to be a little bit more expensive +so for some specific um sorts of food + + align:start position:0% +so for some specific um sorts of food + + + align:start position:0% +so for some specific um sorts of food +you would go in a specific shop so if + + align:start position:0% +you would go in a specific shop so if + + + align:start position:0% +you would go in a specific shop so if +you want to + + align:start position:0% +you want to + + + align:start position:0% +you want to +buy buy + + align:start position:0% + + + + align:start position:0% + +p + + align:start position:0% + + + + align:start position:0% + +p + + align:start position:0% + + + + align:start position:0% + +p you want to buy meat + + align:start position:0% +p you want to buy meat + + + align:start position:0% +p you want to buy meat +you K is where they actually make it it + + align:start position:0% +you K is where they actually make it it + + + align:start position:0% +you K is where they actually make it it +would be + + align:start position:0% + + + + align:start position:0% + +Mach and the store wouldn't be the Mach + + align:start position:0% +Mach and the store wouldn't be the Mach + + + align:start position:0% +Mach and the store wouldn't be the Mach +yes yeah Mach yeah the Macha is the + + align:start position:0% +yes yeah Mach yeah the Macha is the + + + align:start position:0% +yes yeah Mach yeah the Macha is the +first I'm sorry I got distracted + + align:start position:0% + + + + align:start position:0% + +Mach no we don't have Pia that's Pia P + + align:start position:0% +Mach no we don't have Pia that's Pia P + + + align:start position:0% +Mach no we don't have Pia that's Pia P +you want to buy pastries you're going + + align:start position:0% +you want to buy pastries you're going + + + align:start position:0% +you want to buy pastries you're going +PTI + + align:start position:0% +PTI + + + align:start position:0% +PTI +cheria but now you know how to make them + + align:start position:0% +cheria but now you know how to make them + + + align:start position:0% +cheria but now you know how to make them +so you don't need to what about + + align:start position:0% + + + + align:start position:0% + +seafood and you can get fresh fruits and + + align:start position:0% +seafood and you can get fresh fruits and + + + align:start position:0% +seafood and you can get fresh fruits and +vegetable at + + align:start position:0% +vegetable at + + + align:start position:0% +vegetable at +theato theato yeah or you can go to + + align:start position:0% + + + + align:start position:0% + +the + + align:start position:0% +the + + + align:start position:0% +the +fr + + align:start position:0% + + + + align:start position:0% + +okay so you have a lot of different + + align:start position:0% +okay so you have a lot of different + + + align:start position:0% +okay so you have a lot of different +options one another thing that you + + align:start position:0% +options one another thing that you + + + align:start position:0% +options one another thing that you +should keep in mind is that both the + + align:start position:0% +should keep in mind is that both the + + + align:start position:0% +should keep in mind is that both the +super and the smaller neot neio is a + + align:start position:0% +super and the smaller neot neio is a + + + align:start position:0% +super and the smaller neot neio is a +store neio where you + + align:start position:0% +store neio where you + + + align:start position:0% +store neio where you +negotiate yeah you negotiate a lot you + + align:start position:0% +negotiate yeah you negotiate a lot you + + + align:start position:0% +negotiate yeah you negotiate a lot you +can always + + align:start position:0% +can always + + + align:start position:0% +can always +hugle + + align:start position:0% +hugle + + + align:start position:0% +hugle +okay so both super and neot they're + + align:start position:0% +okay so both super and neot they're + + + align:start position:0% +okay so both super and neot they're +usually not open like here + + align:start position:0% +usually not open like here + + + align:start position:0% +usually not open like here +247 so typically they close if you're + + align:start position:0% +247 so typically they close if you're + + + align:start position:0% +247 so typically they close if you're +lucky at 8:00 p.m. or + + align:start position:0% +lucky at 8:00 p.m. or + + + align:start position:0% +lucky at 8:00 p.m. or +earlier they might be closed on Sunday + + align:start position:0% +earlier they might be closed on Sunday + + + align:start position:0% +earlier they might be closed on Sunday +and sometimes they closed on like Monday + + align:start position:0% +and sometimes they closed on like Monday + + + align:start position:0% +and sometimes they closed on like Monday +or Wednesday and some cities they have + + align:start position:0% +or Wednesday and some cities they have + + + align:start position:0% +or Wednesday and some cities they have +different things yeah then another thing + + align:start position:0% +different things yeah then another thing + + + align:start position:0% +different things yeah then another thing +is that the + + align:start position:0% +is that the + + + align:start position:0% +is that the +inotti usually they're closed after + + align:start position:0% +inotti usually they're closed after + + + align:start position:0% +inotti usually they're closed after +lunch so there are another a few things + + align:start position:0% +lunch so there are another a few things + + + align:start position:0% +lunch so there are another a few things +that you should know if you go a super + + align:start position:0% +that you should know if you go a super + + + align:start position:0% +that you should know if you go a super +Med in italan + + align:start position:0% +Med in italan + + + align:start position:0% +Med in italan +okay one thing is that you need to bring + + align:start position:0% +okay one thing is that you need to bring + + + align:start position:0% +okay one thing is that you need to bring +with you a coin + + align:start position:0% +with you a coin + + + align:start position:0% +with you a coin +of or + + align:start position:0% + + + + align:start position:0% + +of + + align:start position:0% +of + + + align:start position:0% +of +what I'm joking we don't we always Sayo + + align:start position:0% +what I'm joking we don't we always Sayo + + + align:start position:0% +what I'm joking we don't we always Sayo +you don't conjugate the + + align:start position:0% + + + + align:start position:0% + +coin okay but you need a + + align:start position:0% + + + + align:start position:0% + +coin yeah see what is + + align:start position:0% +coin yeah see what is + + + align:start position:0% +coin yeah see what is +car yes for the shopping and another + + align:start position:0% +car yes for the shopping and another + + + align:start position:0% +car yes for the shopping and another +thing that's important is that say + + align:start position:0% + + + + align:start position:0% + +super okay they provide you with gloves + + align:start position:0% +super okay they provide you with gloves + + + align:start position:0% +super okay they provide you with gloves +oh wow plastic gloves for Hygiene so you + + align:start position:0% +oh wow plastic gloves for Hygiene so you + + + align:start position:0% +oh wow plastic gloves for Hygiene so you +can't just touch things you have to wear + + align:start position:0% +can't just touch things you have to wear + + + align:start position:0% +can't just touch things you have to wear +these plastic gloves and then you can + + align:start position:0% +these plastic gloves and then you can + + + align:start position:0% +these plastic gloves and then you can +pick your FRA a Vera and then you also + + align:start position:0% +pick your FRA a Vera and then you also + + + align:start position:0% +pick your FRA a Vera and then you also +have to wait + + align:start position:0% +have to wait + + + align:start position:0% +have to wait +it and and tag it price it yourself and + + align:start position:0% +it and and tag it price it yourself and + + + align:start position:0% +it and and tag it price it yourself and +one last thing nobody will help + + align:start position:0% + + + + align:start position:0% + +you what did I say you put the into your + + align:start position:0% +you what did I say you put the into your + + + align:start position:0% +you what did I say you put the into your +nobody's going to help you to put + + align:start position:0% +nobody's going to help you to put + + + align:start position:0% +nobody's going to help you to put +lasa grocer + + align:start position:0% +lasa grocer + + + align:start position:0% +lasa grocer +groceries and the bag well so um you + + align:start position:0% +groceries and the bag well so um you + + + align:start position:0% +groceries and the bag well so um you +either bring your own + + align:start position:0% +either bring your own + + + align:start position:0% +either bring your own +STI or what you do you can get them in + + align:start position:0% +STI or what you do you can get them in + + + align:start position:0% +STI or what you do you can get them in +the supermarket and you pay them they're + + align:start position:0% +the supermarket and you pay them they're + + + align:start position:0% +the supermarket and you pay them they're +not + + align:start position:0% +not + + + align:start position:0% +not +expensive don't remember a few cents but + + align:start position:0% +expensive don't remember a few cents but + + + align:start position:0% +expensive don't remember a few cents but +the idea is that so people do not use + + align:start position:0% +the idea is that so people do not use + + + align:start position:0% +the idea is that so people do not use +too many plastic bags but if you payto + + align:start position:0% +too many plastic bags but if you payto + + + align:start position:0% +too many plastic bags but if you payto +you still have to put the groceries on + + align:start position:0% +you still have to put the groceries on + + + align:start position:0% +you still have to put the groceries on +your + + align:start position:0% +your + + + align:start position:0% +your +own yeah y okay one last thing let's say + + align:start position:0% + + + + align:start position:0% + +that okay so there there are different + + align:start position:0% +that okay so there there are different + + + align:start position:0% +that okay so there there are different +sectors of the + + align:start position:0% +sectors of the + + + align:start position:0% +sectors of the +supermarket the okay so let's say that + + align:start position:0% +supermarket the okay so let's say that + + + align:start position:0% +supermarket the okay so let's say that +you + + align:start position:0% +you + + + align:start position:0% +you +want 100 gr cuz you have to use grams + + align:start position:0% + + + + align:start position:0% + +of + + align:start position:0% + + + + align:start position:0% + +so instead of + + align:start position:0% +so instead of + + + align:start position:0% +so instead of +saying we would + + align:start position:0% + + + + align:start position:0% + +say you know that ETO is the praic that + + align:start position:0% +say you know that ETO is the praic that + + + align:start position:0% +say you know that ETO is the praic that +you use for 100 isn't it + + align:start position:0% +you use for 100 isn't it + + + align:start position:0% +you use for 100 isn't it +so would + + align:start position:0% +so would + + + align:start position:0% +so would +be so I think it's good to keep in mind + + align:start position:0% +be so I think it's good to keep in mind + + + align:start position:0% +be so I think it's good to keep in mind +because maybe you're asking I would + + align:start position:0% + + + + align:start position:0% + +like and then they may + + align:start position:0% + + + + align:start position:0% + +answer the same thing + + align:start position:0% + + + + align:start position:0% + +is is too much + + align:start position:0% + + + + align:start position:0% + +so \ No newline at end of file diff --git a/Kqf0uO0oV6s.txt b/Kqf0uO0oV6s.txt new file mode 100644 index 0000000000000000000000000000000000000000..3c9f817f83595e98f0bdcea92378b72ba858539a --- /dev/null +++ b/Kqf0uO0oV6s.txt @@ -0,0 +1,11889 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT open courseware continue + + align:start position:0% +will help MIT open courseware continue + + + align:start position:0% +will help MIT open courseware continue +to offer high quality educational + + align:start position:0% +to offer high quality educational + + + align:start position:0% +to offer high quality educational +resources for free to make a donation or + + align:start position:0% +resources for free to make a donation or + + + align:start position:0% +resources for free to make a donation or +view additional materials from hundreds + + align:start position:0% +view additional materials from hundreds + + + align:start position:0% +view additional materials from hundreds +of MIT courses visit MIT open courseware + + align:start position:0% +of MIT courses visit MIT open courseware + + + align:start position:0% +of MIT courses visit MIT open courseware +at + + align:start position:0% + + + + align:start position:0% + +ocw.mit.edu this week uh we're going to + + align:start position:0% +ocw.mit.edu this week uh we're going to + + + align:start position:0% +ocw.mit.edu this week uh we're going to +talk about recurrences how to set them + + align:start position:0% +talk about recurrences how to set them + + + align:start position:0% +talk about recurrences how to set them +up how to model a problem as a recurrent + + align:start position:0% +up how to model a problem as a recurrent + + + align:start position:0% +up how to model a problem as a recurrent +problem and then how to solve them uh + + align:start position:0% +problem and then how to solve them uh + + + align:start position:0% +problem and then how to solve them uh +this stuff is really useful when you get + + align:start position:0% +this stuff is really useful when you get + + + align:start position:0% +this stuff is really useful when you get +into algorithm design and algorithm + + align:start position:0% +into algorithm design and algorithm + + + align:start position:0% +into algorithm design and algorithm +analysis 66 and 6046 we use this stuff a + + align:start position:0% +analysis 66 and 6046 we use this stuff a + + + align:start position:0% +analysis 66 and 6046 we use this stuff a +lot we're going to start with a very + + align:start position:0% +lot we're going to start with a very + + + align:start position:0% +lot we're going to start with a very +famous recurrent problem known as the + + align:start position:0% +famous recurrent problem known as the + + + align:start position:0% +famous recurrent problem known as the +towers of Hanoi problem and I'm guessing + + align:start position:0% +towers of Hanoi problem and I'm guessing + + + align:start position:0% +towers of Hanoi problem and I'm guessing +that many of you have seen this problem + + align:start position:0% +that many of you have seen this problem + + + align:start position:0% +that many of you have seen this problem +one form or another uh in the tower of + + align:start position:0% +one form or another uh in the tower of + + + align:start position:0% +one form or another uh in the tower of +Hanoi problem you got three pegs and N + + align:start position:0% +Hanoi problem you got three pegs and N + + + align:start position:0% +Hanoi problem you got three pegs and N +discs these little guys here all + + align:start position:0% +discs these little guys here all + + + align:start position:0% +discs these little guys here all +different sizes and the object is to + + align:start position:0% +different sizes and the object is to + + + align:start position:0% +different sizes and the object is to +start with a stack like this and move + + align:start position:0% +start with a stack like this and move + + + align:start position:0% +start with a stack like this and move +the discs around so they wind up with + + align:start position:0% +the discs around so they wind up with + + + align:start position:0% +the discs around so they wind up with +the stack on another disc now the rules + + align:start position:0% +the stack on another disc now the rules + + + align:start position:0% +the stack on another disc now the rules +are you can only move one disc at a + + align:start position:0% +are you can only move one disc at a + + + align:start position:0% +are you can only move one disc at a +time and you can never put a big disc + + align:start position:0% +time and you can never put a big disc + + + align:start position:0% +time and you can never put a big disc +over a little disc so that you can't do + + align:start position:0% +over a little disc so that you can't do + + + align:start position:0% +over a little disc so that you can't do +so that would have to go there then you + + align:start position:0% +so that would have to go there then you + + + align:start position:0% +so that would have to go there then you +could do this and now I've got gotten + + align:start position:0% +could do this and now I've got gotten + + + align:start position:0% +could do this and now I've got gotten +the top two moved over to here and the + + align:start position:0% +the top two moved over to here and the + + + align:start position:0% +the top two moved over to here and the +goal is to take the minimum number of + + align:start position:0% +goal is to take the minimum number of + + + align:start position:0% +goal is to take the minimum number of +moves to get the whole stack moved over + + align:start position:0% +moves to get the whole stack moved over + + + align:start position:0% +moves to get the whole stack moved over +to here and to even figure out if that's + + align:start position:0% +to here and to even figure out if that's + + + align:start position:0% +to here and to even figure out if that's +doable + + align:start position:0% +doable + + + align:start position:0% +doable +now this was invented by a famous French + + align:start position:0% +now this was invented by a famous French + + + align:start position:0% +now this was invented by a famous French +mathematician named Edward Lucas in + + align:start position:0% +mathematician named Edward Lucas in + + + align:start position:0% +mathematician named Edward Lucas in +1883 and in the original Legend around + + align:start position:0% +1883 and in the original Legend around + + + align:start position:0% +1883 and in the original Legend around +this puzzle there were 64 four discs + + align:start position:0% +this puzzle there were 64 four discs + + + align:start position:0% +this puzzle there were 64 four discs +this one has just seven on + + align:start position:0% +this one has just seven on + + + align:start position:0% +this one has just seven on +it and the story was at the beginning of + + align:start position:0% +it and the story was at the beginning of + + + align:start position:0% +it and the story was at the beginning of +time God placed the 64 discs on one of + + align:start position:0% +time God placed the 64 discs on one of + + + align:start position:0% +time God placed the 64 discs on one of +the three golden pegs and he or got an + + align:start position:0% +the three golden pegs and he or got an + + + align:start position:0% +the three golden pegs and he or got an +order of monks whose lifelong mission + + align:start position:0% +order of monks whose lifelong mission + + + align:start position:0% +order of monks whose lifelong mission +was to move the disc one at a time so at + + align:start position:0% +was to move the disc one at a time so at + + + align:start position:0% +was to move the disc one at a time so at +the end all 64 discs were lined up on an + + align:start position:0% +the end all 64 discs were lined up on an + + + align:start position:0% +the end all 64 discs were lined up on an +adjacent Peg and according to Legend + + align:start position:0% +adjacent Peg and according to Legend + + + align:start position:0% +adjacent Peg and according to Legend +when that task was done the tower would + + align:start position:0% +when that task was done the tower would + + + align:start position:0% +when that task was done the tower would +crumble and the world would end uh sort + + align:start position:0% +crumble and the world would end uh sort + + + align:start position:0% +crumble and the world would end uh sort +of explains why MOS why monks are never + + align:start position:0% +of explains why MOS why monks are never + + + align:start position:0% +of explains why MOS why monks are never +smiling because they work forever and + + align:start position:0% +smiling because they work forever and + + + align:start position:0% +smiling because they work forever and +then just something bad happens now the + + align:start position:0% +then just something bad happens now the + + + align:start position:0% +then just something bad happens now the +question we want to be able to answer is + + align:start position:0% +question we want to be able to answer is + + + align:start position:0% +question we want to be able to answer is +how long till the world + + align:start position:0% +how long till the world + + + align:start position:0% +how long till the world +ends so we could start with a simpler + + align:start position:0% +ends so we could start with a simpler + + + align:start position:0% +ends so we could start with a simpler +version + + align:start position:0% +version + + + align:start position:0% +version +say let's take three discs and start + + align:start position:0% +say let's take three discs and start + + + align:start position:0% +say let's take three discs and start +with that and let's see you know is a + + align:start position:0% +with that and let's see you know is a + + + align:start position:0% +with that and let's see you know is a +doable well we could that's + + align:start position:0% +doable well we could that's + + + align:start position:0% +doable well we could that's +one that's + + align:start position:0% +one that's + + + align:start position:0% +one that's +two + + align:start position:0% +two + + + align:start position:0% +two +three + + align:start position:0% +three + + + align:start position:0% +three + + align:start position:0% + + + align:start position:0% +five + + align:start position:0% +five + + + align:start position:0% +five +6 7 so it's doable with three discs and + + align:start position:0% +6 7 so it's doable with three discs and + + + align:start position:0% +6 7 so it's doable with three discs and +we took seven moves maybe maybe there's + + align:start position:0% +we took seven moves maybe maybe there's + + + align:start position:0% +we took seven moves maybe maybe there's +a better way and that's part of what + + align:start position:0% +a better way and that's part of what + + + align:start position:0% +a better way and that's part of what +we'll try to study today um in fact what + + align:start position:0% +we'll try to study today um in fact what + + + align:start position:0% +we'll try to study today um in fact what +we'd like to know is how many moves + + align:start position:0% +we'd like to know is how many moves + + + align:start position:0% +we'd like to know is how many moves +moves for n + + align:start position:0% + + + + align:start position:0% + +discs and is it even finite so we're + + align:start position:0% +discs and is it even finite so we're + + + align:start position:0% +discs and is it even finite so we're +going to define t subn to be the minimum + + align:start position:0% +going to define t subn to be the minimum + + + align:start position:0% +going to define t subn to be the minimum +number of + + align:start position:0% + + + + align:start position:0% + +moves for n diss so to take a stack of + + align:start position:0% +moves for n diss so to take a stack of + + + align:start position:0% +moves for n diss so to take a stack of +end discs and move them to an adjacent + + align:start position:0% +end discs and move them to an adjacent + + + align:start position:0% +end discs and move them to an adjacent +Peg so for example what's + + align:start position:0% +Peg so for example what's + + + align:start position:0% +Peg so for example what's +T1 one I got one peg I just move it + + align:start position:0% +T1 one I got one peg I just move it + + + align:start position:0% +T1 one I got one peg I just move it +that's + + align:start position:0% +that's + + + align:start position:0% +that's +easy + + align:start position:0% +easy + + + align:start position:0% +easy +T2 three move the little guy move the + + align:start position:0% +T2 three move the little guy move the + + + align:start position:0% +T2 three move the little guy move the +base move the little guy back on top + + align:start position:0% +base move the little guy back on top + + + align:start position:0% +base move the little guy back on top +that's the best you can do and we've + + align:start position:0% +that's the best you can do and we've + + + align:start position:0% +that's the best you can do and we've +seen that T3 is at most + + align:start position:0% +seen that T3 is at most + + + align:start position:0% +seen that T3 is at most +seven maybe maybe there's a better way + + align:start position:0% +seven maybe maybe there's a better way + + + align:start position:0% +seven maybe maybe there's a better way +but let's try to first get an upper + + align:start position:0% +but let's try to first get an upper + + + align:start position:0% +but let's try to first get an upper +bound on + + align:start position:0% +bound on + + + align:start position:0% +bound on +this any thoughts about how we might go + + align:start position:0% +this any thoughts about how we might go + + + align:start position:0% +this any thoughts about how we might go +about a general upper Bound for + + align:start position:0% +about a general upper Bound for + + + align:start position:0% +about a general upper Bound for +n for this + + align:start position:0% +n for this + + + align:start position:0% +n for this +problem like say I had four discs any + + align:start position:0% +problem like say I had four discs any + + + align:start position:0% +problem like say I had four discs any +thoughts about a strategy where we might + + align:start position:0% +thoughts about a strategy where we might + + + align:start position:0% +thoughts about a strategy where we might +be able to analyze or get an upper bound + + align:start position:0% +be able to analyze or get an upper bound + + + align:start position:0% +be able to analyze or get an upper bound +on the number of steps for four discs + + align:start position:0% +on the number of steps for four discs + + + align:start position:0% +on the number of steps for four discs +here or more discs any thoughts + + align:start position:0% + + + + align:start position:0% + +yeah all right look at the three disk + + align:start position:0% +yeah all right look at the three disk + + + align:start position:0% +yeah all right look at the three disk +problem that's a good idea in fact + + align:start position:0% +problem that's a good idea in fact + + + align:start position:0% +problem that's a good idea in fact +fact you know I could look at the three + + align:start position:0% +fact you know I could look at the three + + + align:start position:0% +fact you know I could look at the three +dis problem recursively I got these + + align:start position:0% +dis problem recursively I got these + + + align:start position:0% +dis problem recursively I got these +three discs say I move them over a + + align:start position:0% +three discs say I move them over a + + + align:start position:0% +three discs say I move them over a +series of steps seven steps at most to + + align:start position:0% +series of steps seven steps at most to + + + align:start position:0% +series of steps seven steps at most to +put them + + align:start position:0% +put them + + + align:start position:0% +put them +here what would I do + + align:start position:0% + + + + align:start position:0% + +next move the lower one and then do this + + align:start position:0% +next move the lower one and then do this + + + align:start position:0% +next move the lower one and then do this +recurrent problem again + + align:start position:0% +recurrent problem again + + + align:start position:0% +recurrent problem again +back all right so we can take a problem + + align:start position:0% +back all right so we can take a problem + + + align:start position:0% +back all right so we can take a problem +with n Diss and solve it recursively + + align:start position:0% +with n Diss and solve it recursively + + + align:start position:0% +with n Diss and solve it recursively +let's see what happens when we do + + align:start position:0% + + + + align:start position:0% + +that so let's look at a recursive + + align:start position:0% + + + + align:start position:0% + +solution and let's draw it for n so the + + align:start position:0% +solution and let's draw it for n so the + + + align:start position:0% +solution and let's draw it for n so the +first + + align:start position:0% +first + + + align:start position:0% +first +phase that you described is I start here + + align:start position:0% +phase that you described is I start here + + + align:start position:0% +phase that you described is I start here +are my three pegs and I start with this + + align:start position:0% +are my three pegs and I start with this + + + align:start position:0% +are my three pegs and I start with this +one 2 three down to n here and nothing + + align:start position:0% +one 2 three down to n here and nothing + + + align:start position:0% +one 2 three down to n here and nothing +on these + + align:start position:0% +on these + + + align:start position:0% +on these +pegs and I'm going to use cursion to + + align:start position:0% +pegs and I'm going to use cursion to + + + align:start position:0% +pegs and I'm going to use cursion to +take the top n minus one and move them + + align:start position:0% +take the top n minus one and move them + + + align:start position:0% +take the top n minus one and move them +out here so I leave the nth guy there + + align:start position:0% +out here so I leave the nth guy there + + + align:start position:0% +out here so I leave the nth guy there +nothing here and I go one two to n minus + + align:start position:0% +nothing here and I go one two to n minus + + + align:start position:0% +nothing here and I go one two to n minus +one how many steps does that move take + + align:start position:0% +one how many steps does that move take + + + align:start position:0% +one how many steps does that move take +that series of moves take that + + align:start position:0% +that series of moves take that + + + align:start position:0% +that series of moves take that +phase in terms of + + align:start position:0% +phase in terms of + + + align:start position:0% +phase in terms of +t t of n minus one because I'm taking an + + align:start position:0% +t t of n minus one because I'm taking an + + + align:start position:0% +t t of n minus one because I'm taking an +N minus one dis stack and moving it so + + align:start position:0% +N minus one dis stack and moving it so + + + align:start position:0% +N minus one dis stack and moving it so +that is is TN minus one + + align:start position:0% + + + + align:start position:0% + +steps all right now my next + + align:start position:0% +steps all right now my next + + + align:start position:0% +steps all right now my next +move is to take this guy and stick him + + align:start position:0% +move is to take this guy and stick him + + + align:start position:0% +move is to take this guy and stick him +here so we'll draw that over here so the + + align:start position:0% +here so we'll draw that over here so the + + + align:start position:0% +here so we'll draw that over here so the +nth guy moves there and I leave all + + align:start position:0% +nth guy moves there and I leave all + + + align:start position:0% +nth guy moves there and I leave all +these guys + + align:start position:0% +these guys + + + align:start position:0% +these guys +here that's going to be phase + + align:start position:0% + + + + align:start position:0% + +two I move the largest disc + + align:start position:0% + + + + align:start position:0% + +and how many steps did that + + align:start position:0% +and how many steps did that + + + align:start position:0% +and how many steps did that +take one step just move one + + align:start position:0% + + + + align:start position:0% + +dis one step for that and then my last + + align:start position:0% +dis one step for that and then my last + + + align:start position:0% +dis one step for that and then my last +phase is to take all these and move them + + align:start position:0% +phase is to take all these and move them + + + align:start position:0% +phase is to take all these and move them +on to here + + align:start position:0% + + + + align:start position:0% + +and so then it looks like final result 1 + + align:start position:0% +and so then it looks like final result 1 + + + align:start position:0% +and so then it looks like final result 1 +2 over n minus one over n and how many + + align:start position:0% +2 over n minus one over n and how many + + + align:start position:0% +2 over n minus one over n and how many +steps does phase three + + align:start position:0% + + + + align:start position:0% + +take TN minus one + + align:start position:0% + + + + align:start position:0% + +good all right so we've got an algorithm + + align:start position:0% +good all right so we've got an algorithm + + + align:start position:0% +good all right so we've got an algorithm +now recursive algorithm and the total + + align:start position:0% + + + + align:start position:0% + +time the number of moves + + align:start position:0% + + + + align:start position:0% + +TN is at + + align:start position:0% +TN is at + + + align:start position:0% +TN is at +most TN minus1 plus tnus one is 2 TN + + align:start position:0% +most TN minus1 plus tnus one is 2 TN + + + align:start position:0% +most TN minus1 plus tnus one is 2 TN +minus + + align:start position:0% +minus + + + align:start position:0% +minus +one plus the one step up + + align:start position:0% +one plus the one step up + + + align:start position:0% +one plus the one step up +there for example which we already know + + align:start position:0% +there for example which we already know + + + align:start position:0% +there for example which we already know +T3 is at most T 2 T2 + 1 which is 2 * 3 + + align:start position:0% +T3 is at most T 2 T2 + 1 which is 2 * 3 + + + align:start position:0% +T3 is at most T 2 T2 + 1 which is 2 * 3 ++ one is + + align:start position:0% ++ one is + + + align:start position:0% ++ one is +seven so we already knew we could do it + + align:start position:0% +seven so we already knew we could do it + + + align:start position:0% +seven so we already knew we could do it +in Seven what's an upper bound on the + + align:start position:0% +in Seven what's an upper bound on the + + + align:start position:0% +in Seven what's an upper bound on the +time to move four + + align:start position:0% +time to move four + + + align:start position:0% +time to move four +discs + + align:start position:0% +discs + + + align:start position:0% +discs + + align:start position:0% + + + align:start position:0% +okay all right so T4 is at most + + align:start position:0% +okay all right so T4 is at most + + + align:start position:0% +okay all right so T4 is at most +15 but maybe there's a better way this + + align:start position:0% +15 but maybe there's a better way this + + + align:start position:0% +15 but maybe there's a better way this +is just one way to do it in fact how + + align:start position:0% +is just one way to do it in fact how + + + align:start position:0% +is just one way to do it in fact how +many people think there's a better way + + align:start position:0% +many people think there's a better way + + + align:start position:0% +many people think there's a better way +than this + + align:start position:0% +than this + + + align:start position:0% +than this +approach all right how many people think + + align:start position:0% +approach all right how many people think + + + align:start position:0% +approach all right how many people think +there is no better way all right very + + align:start position:0% +there is no better way all right very + + + align:start position:0% +there is no better way all right very +good yeah this is the best you can do + + align:start position:0% +good yeah this is the best you can do + + + align:start position:0% +good yeah this is the best you can do +and let's prove that let's get a lower B + + align:start position:0% + + + + align:start position:0% + +found all right to see why this is + + align:start position:0% +found all right to see why this is + + + align:start position:0% +found all right to see why this is +optimal think about the step where the + + align:start position:0% +optimal think about the step where the + + + align:start position:0% +optimal think about the step where the +nth disc moves at some point in our + + align:start position:0% +nth disc moves at some point in our + + + align:start position:0% +nth disc moves at some point in our +procedure the biggest disc has to + + align:start position:0% +procedure the biggest disc has to + + + align:start position:0% +procedure the biggest disc has to +move now it could move to this Peg or + + align:start position:0% +move now it could move to this Peg or + + + align:start position:0% +move now it could move to this Peg or +that Peg doesn't really matter but when + + align:start position:0% +that Peg doesn't really matter but when + + + align:start position:0% +that Peg doesn't really matter but when +it + + align:start position:0% +it + + + align:start position:0% +it +moves what do I know had to have + + align:start position:0% +moves what do I know had to have + + + align:start position:0% +moves what do I know had to have +happened before that guy + + align:start position:0% + + + + align:start position:0% + +moved everything on top of it had to + + align:start position:0% +moved everything on top of it had to + + + align:start position:0% +moved everything on top of it had to +move to the other + + align:start position:0% +move to the other + + + align:start position:0% +move to the other +Peg I started with one through n minus + + align:start position:0% +Peg I started with one through n minus + + + align:start position:0% +Peg I started with one through n minus +one here none of them can be here they + + align:start position:0% +one here none of them can be here they + + + align:start position:0% +one here none of them can be here they +all have to be + + align:start position:0% +all have to be + + + align:start position:0% +all have to be +here okay so that means that I have to + + align:start position:0% +here okay so that means that I have to + + + align:start position:0% +here okay so that means that I have to +have had TN minus one + + align:start position:0% +have had TN minus one + + + align:start position:0% +have had TN minus one +steps so at least TN minus one steps + + align:start position:0% + + + + align:start position:0% + +before the big disc + + align:start position:0% + + + + align:start position:0% + +moves all right then there is the step + + align:start position:0% +moves all right then there is the step + + + align:start position:0% +moves all right then there is the step +when the big guy + + align:start position:0% +when the big guy + + + align:start position:0% +when the big guy +moves all right one step for the big guy + + align:start position:0% +moves all right one step for the big guy + + + align:start position:0% +moves all right one step for the big guy +to + + align:start position:0% + + + + align:start position:0% + +move cuz it's got to move at least once + + align:start position:0% + + + + align:start position:0% + +and then after it moves I got to get + + align:start position:0% +and then after it moves I got to get + + + align:start position:0% +and then after it moves I got to get +everything else one way or another on + + align:start position:0% +everything else one way or another on + + + align:start position:0% +everything else one way or another on +top of + + align:start position:0% +top of + + + align:start position:0% +top of +it at some point after the last time the + + align:start position:0% +it at some point after the last time the + + + align:start position:0% +it at some point after the last time the +big guy moves everything else has to go + + align:start position:0% +big guy moves everything else has to go + + + align:start position:0% +big guy moves everything else has to go +on + + align:start position:0% +on + + + align:start position:0% +on +top and that's another TN minus one + + align:start position:0% + + + + align:start position:0% + +steps so after the last time the big guy + + align:start position:0% +steps so after the last time the big guy + + + align:start position:0% +steps so after the last time the big guy +moves + + align:start position:0% + + + + align:start position:0% + +you got to take TN minus one + + align:start position:0% + + + + align:start position:0% + +steps okay so that means there's a lower + + align:start position:0% +steps okay so that means there's a lower + + + align:start position:0% +steps okay so that means there's a lower +bound that no matter what you + + align:start position:0% +bound that no matter what you + + + align:start position:0% +bound that no matter what you +do TN is at least 2 TN minus one + + + align:start position:0% +do TN is at least 2 TN minus one + + + + align:start position:0% +do TN is at least 2 TN minus one + +one and so in fact it's + + align:start position:0% +one and so in fact it's + + + align:start position:0% +one and so in fact it's +equal TN equal 2 TN minus1 + 1 + + align:start position:0% +equal TN equal 2 TN minus1 + 1 + + + align:start position:0% +equal TN equal 2 TN minus1 + 1 +so T3 is seven T4 is + + align:start position:0% +so T3 is seven T4 is + + + align:start position:0% +so T3 is seven T4 is +15 any + + align:start position:0% + + + + align:start position:0% + +questions about + + align:start position:0% + + + + align:start position:0% + +that all right well we'd like to know + + align:start position:0% +that all right well we'd like to know + + + align:start position:0% +that all right well we'd like to know +how long till the world ends which is T + + align:start position:0% +how long till the world ends which is T + + + align:start position:0% +how long till the world ends which is T +64 so we'd like to get a formula for T + + align:start position:0% +64 so we'd like to get a formula for T + + + align:start position:0% +64 so we'd like to get a formula for T +of n we could just compute it 64 times + + align:start position:0% +of n we could just compute it 64 times + + + align:start position:0% +of n we could just compute it 64 times +and see um but much nicer just to get a + + align:start position:0% +and see um but much nicer just to get a + + + align:start position:0% +and see um but much nicer just to get a +formula and that's what we're going to + + align:start position:0% +formula and that's what we're going to + + + align:start position:0% +formula and that's what we're going to +learn how to do this week is to get + + align:start position:0% +learn how to do this week is to get + + + align:start position:0% +learn how to do this week is to get +formulas close form Expressions to solve + + align:start position:0% +formulas close form Expressions to solve + + + align:start position:0% +formulas close form Expressions to solve +recurrences and there's a bunch of + + align:start position:0% +recurrences and there's a bunch of + + + align:start position:0% +recurrences and there's a bunch of +different methods you can use and we're + + align:start position:0% +different methods you can use and we're + + + align:start position:0% +different methods you can use and we're +going to talk about them the uh simplest + + align:start position:0% +going to talk about them the uh simplest + + + align:start position:0% +going to talk about them the uh simplest +is to guess the answer and then check it + + align:start position:0% +is to guess the answer and then check it + + + align:start position:0% +is to guess the answer and then check it +it's called guess and + + align:start position:0% +it's called guess and + + + align:start position:0% +it's called guess and +verify also known as the substitution + + align:start position:0% +verify also known as the substitution + + + align:start position:0% +verify also known as the substitution +method + + align:start position:0% + + + + align:start position:0% + +now what's a good guess for T of + + align:start position:0% + + + + align:start position:0% + +n 2 the N minus one you got T of one is + + align:start position:0% +n 2 the N minus one you got T of one is + + + align:start position:0% +n 2 the N minus one you got T of one is +1 T of two is three T of3 is seven T of + + align:start position:0% +1 T of two is three T of3 is seven T of + + + align:start position:0% +1 T of two is three T of3 is seven T of +four is 15 you know you won't compute + + align:start position:0% +four is 15 you know you won't compute + + + align:start position:0% +four is 15 you know you won't compute +too many before you + + align:start position:0% + + + + align:start position:0% + +guess that t of n is 2 the N minus one + + align:start position:0% + + + + align:start position:0% + +all right now that doesn't mean it's + + align:start position:0% +all right now that doesn't mean it's + + + align:start position:0% +all right now that doesn't mean it's +true so how are we going to verify that + + align:start position:0% +true so how are we going to verify that + + + align:start position:0% +true so how are we going to verify that +guess what proof + + align:start position:0% +guess what proof + + + align:start position:0% +guess what proof +technique induction it just keeps coming + + align:start position:0% +technique induction it just keeps coming + + + align:start position:0% +technique induction it just keeps coming +back just never never finish with + + align:start position:0% +back just never never finish with + + + align:start position:0% +back just never never finish with +induction so we're going to verify + + align:start position:0% +induction so we're going to verify + + + align:start position:0% +induction so we're going to verify +this by + + align:start position:0% + + + + align:start position:0% + +induction what what's our induction + + align:start position:0% + + + + align:start position:0% + +hypothesis any + + align:start position:0% + + + + align:start position:0% + +thoughts right there P of n is going to + + align:start position:0% +thoughts right there P of n is going to + + + align:start position:0% +thoughts right there P of n is going to +be that tnal 2 the N minus one all right + + align:start position:0% +be that tnal 2 the N minus one all right + + + align:start position:0% +be that tnal 2 the N minus one all right +very + + align:start position:0% + + + + align:start position:0% + +typical so the predicate is that t of n + + align:start position:0% +typical so the predicate is that t of n + + + align:start position:0% +typical so the predicate is that t of n +is 2 the N minus one base + + align:start position:0% + + + + align:start position:0% + +case we'll pick Nal 1 + + align:start position:0% +case we'll pick Nal 1 + + + align:start position:0% +case we'll pick Nal 1 +T of 1 is 1 and that is 2 1us 1 so the + + align:start position:0% +T of 1 is 1 and that is 2 1us 1 so the + + + align:start position:0% +T of 1 is 1 and that is 2 1us 1 so the +base case + + align:start position:0% +base case + + + align:start position:0% +base case +works now we'll do the inductive + + align:start position:0% + + + + align:start position:0% + +step we're going to + + align:start position:0% +step we're going to + + + align:start position:0% +step we're going to +assume P of n we're going to assume that + + align:start position:0% +assume P of n we're going to assume that + + + align:start position:0% +assume P of n we're going to assume that +TN equals 2 to the N minus1 to prove PN + + align:start position:0% +TN equals 2 to the N minus1 to prove PN + + + align:start position:0% +TN equals 2 to the N minus1 to prove PN +minus1 which is T n + 1 = 2 n + 1us 1 so + + align:start position:0% +minus1 which is T n + 1 = 2 n + 1us 1 so + + + align:start position:0% +minus1 which is T n + 1 = 2 n + 1us 1 so +very standard induction so let's look at + + align:start position:0% +very standard induction so let's look at + + + align:start position:0% +very standard induction so let's look at +TN + one + + align:start position:0% +TN + one + + + align:start position:0% +TN + one +now TN + 1 equal 2 + + align:start position:0% +now TN + 1 equal 2 + + + align:start position:0% +now TN + 1 equal 2 +TN + 1 uh yeah 2 tn+ + + align:start position:0% +TN + 1 uh yeah 2 tn+ + + + align:start position:0% +TN + 1 uh yeah 2 tn+ +one now we plug in here that's just the + + align:start position:0% +one now we plug in here that's just the + + + align:start position:0% +one now we plug in here that's just the +recurrence now we plug in using our + + align:start position:0% +recurrence now we plug in using our + + + align:start position:0% +recurrence now we plug in using our +assumption from the induction this is + + align:start position:0% +assumption from the induction this is + + + align:start position:0% +assumption from the induction this is +two + + align:start position:0% + + + + align:start position:0% + +2 the N - 1 + 1 multiply the two that's + + align:start position:0% +2 the N - 1 + 1 multiply the two that's + + + align:start position:0% +2 the N - 1 + 1 multiply the two that's +2 the n + 1 -2 + 1 is + + align:start position:0% +2 the n + 1 -2 + 1 is + + + align:start position:0% +2 the n + 1 -2 + 1 is +minus1 and so we're + + align:start position:0% +minus1 and so we're + + + align:start position:0% +minus1 and so we're +done all right so we guessed the answer + + align:start position:0% +done all right so we guessed the answer + + + align:start position:0% +done all right so we guessed the answer +it was a pretty easy guess very simple + + align:start position:0% +it was a pretty easy guess very simple + + + align:start position:0% +it was a pretty easy guess very simple +to prove it by + + align:start position:0% +to prove it by + + + align:start position:0% +to prove it by +induction any + + align:start position:0% + + + + align:start position:0% + +questions all right how long would it + + align:start position:0% +questions all right how long would it + + + align:start position:0% +questions all right how long would it +take me to do all seven discs on this + + align:start position:0% +take me to do all seven discs on this + + + align:start position:0% +take me to do all seven discs on this +puzzle here + + align:start position:0% +puzzle here + + + align:start position:0% +puzzle here +how many + + align:start position:0% + + + + align:start position:0% + +steps 127 steps how long till the end of + + align:start position:0% +steps 127 steps how long till the end of + + + align:start position:0% +steps 127 steps how long till the end of +the + + align:start position:0% +the + + + align:start position:0% +the +world a long time 2 to the 64th minus 1 + + align:start position:0% +world a long time 2 to the 64th minus 1 + + + align:start position:0% +world a long time 2 to the 64th minus 1 +is 18 billion billion moves so going to + + align:start position:0% +is 18 billion billion moves so going to + + + align:start position:0% +is 18 billion billion moves so going to +keep those monks busy for a little + + align:start position:0% +keep those monks busy for a little + + + align:start position:0% +keep those monks busy for a little +while before the world + + align:start position:0% +while before the world + + + align:start position:0% +while before the world +ends now in general this method is sort + + align:start position:0% +ends now in general this method is sort + + + align:start position:0% +ends now in general this method is sort +of the best method for solving a + + align:start position:0% +of the best method for solving a + + + align:start position:0% +of the best method for solving a +recurrence we'll see lots of examples + + align:start position:0% +recurrence we'll see lots of examples + + + align:start position:0% +recurrence we'll see lots of examples +where it works great the only problem is + + align:start position:0% +where it works great the only problem is + + + align:start position:0% +where it works great the only problem is +it requires that Divine Insight thing + + align:start position:0% +it requires that Divine Insight thing + + + align:start position:0% +it requires that Divine Insight thing +that guess to guess the right answer + + align:start position:0% +that guess to guess the right answer + + + align:start position:0% +that guess to guess the right answer +obviously if you guess the wrong answer + + align:start position:0% +obviously if you guess the wrong answer + + + align:start position:0% +obviously if you guess the wrong answer +it's not going to not going to work + + align:start position:0% +it's not going to not going to work + + + align:start position:0% +it's not going to not going to work +guessing is many times easy but not + + align:start position:0% +guessing is many times easy but not + + + align:start position:0% +guessing is many times easy but not +always um so you need other methods when + + align:start position:0% +always um so you need other methods when + + + align:start position:0% +always um so you need other methods when +you can't guess it the next most common + + align:start position:0% +you can't guess it the next most common + + + align:start position:0% +you can't guess it the next most common +method is called has a lot of names + + align:start position:0% +method is called has a lot of names + + + align:start position:0% +method is called has a lot of names +called plug and + + align:start position:0% +called plug and + + + align:start position:0% +called plug and +chug uh expansion iteration Brute Force + + align:start position:0% +chug uh expansion iteration Brute Force + + + align:start position:0% +chug uh expansion iteration Brute Force +exhaustion + + align:start position:0% +exhaustion + + + align:start position:0% +exhaustion +um let me show you how that works on + + align:start position:0% +um let me show you how that works on + + + align:start position:0% +um let me show you how that works on +this + + align:start position:0% + + + + align:start position:0% + +example okay so plug and + + align:start position:0% + + + + align:start position:0% + +chug so we'll solve the same + + align:start position:0% +chug so we'll solve the same + + + align:start position:0% +chug so we'll solve the same +recurrence so we've got TN equals and + + align:start position:0% +recurrence so we've got TN equals and + + + align:start position:0% +recurrence so we've got TN equals and +I'm going to write it just reverse 1 + + align:start position:0% +I'm going to write it just reverse 1 + + + align:start position:0% +I'm going to write it just reverse 1 +plus 2 TN because I'm going to expand + + align:start position:0% +plus 2 TN because I'm going to expand + + + align:start position:0% +plus 2 TN because I'm going to expand +out the recurrent term it's why it's + + align:start position:0% +out the recurrent term it's why it's + + + align:start position:0% +out the recurrent term it's why it's +called expansion + + align:start position:0% +called expansion + + + align:start position:0% +called expansion +also well that's equal to 1 + 2 now I + + align:start position:0% +also well that's equal to 1 + 2 now I + + + align:start position:0% +also well that's equal to 1 + 2 now I +expand this out using the recurrence 1 + + + align:start position:0% +expand this out using the recurrence 1 + + + + align:start position:0% +expand this out using the recurrence 1 + +2 TN minus + + align:start position:0% + + + + align:start position:0% + +one all right now I do a little chugging + + align:start position:0% +one all right now I do a little chugging + + + align:start position:0% +one all right now I do a little chugging +here so I plugged + + align:start position:0% +here so I plugged + + + align:start position:0% +here so I plugged +here now I'll do + + align:start position:0% +here now I'll do + + + align:start position:0% +here now I'll do +chug that's 1 + 2 + 4 TN + + align:start position:0% +chug that's 1 + 2 + 4 TN + + + align:start position:0% +chug that's 1 + 2 + 4 TN +minus1 now I'm going to plug in + + align:start position:0% +minus1 now I'm going to plug in + + + align:start position:0% +minus1 now I'm going to plug in +again what + + align:start position:0% + + + + align:start position:0% + +that you're + + align:start position:0% +that you're + + + align:start position:0% +that you're +right you're right I got to get minus + + align:start position:0% +right you're right I got to get minus + + + align:start position:0% +right you're right I got to get minus +one here and minus two here that is + + align:start position:0% +one here and minus two here that is + + + align:start position:0% +one here and minus two here that is +correct very good I would have run into + + align:start position:0% +correct very good I would have run into + + + align:start position:0% +correct very good I would have run into +trouble that's + + align:start position:0% +trouble that's + + + align:start position:0% +trouble that's +good all right now I plug in here 1 + 2 + + align:start position:0% +good all right now I plug in here 1 + 2 + + + align:start position:0% +good all right now I plug in here 1 + 2 ++ 4 4 1 + 2 tnus + + align:start position:0% ++ 4 4 1 + 2 tnus + + + align:start position:0% ++ 4 4 1 + 2 tnus +3 then we do the + + align:start position:0% + + + + align:start position:0% + +Chug 1 + 2 + 4 + 8 TN minus + + align:start position:0% +Chug 1 + 2 + 4 + 8 TN minus + + + align:start position:0% +Chug 1 + 2 + 4 + 8 TN minus +3 all right and now we're going to try + + align:start position:0% +3 all right and now we're going to try + + + align:start position:0% +3 all right and now we're going to try +to observe the pattern we're getting so + + align:start position:0% +to observe the pattern we're getting so + + + align:start position:0% +to observe the pattern we're getting so +there's a little bit of a guess going on + + align:start position:0% +there's a little bit of a guess going on + + + align:start position:0% +there's a little bit of a guess going on +in this context still but you see the + + align:start position:0% +in this context still but you see the + + + align:start position:0% +in this context still but you see the +pattern we got powers of two pretty easy + + align:start position:0% +pattern we got powers of two pretty easy + + + align:start position:0% +pattern we got powers of two pretty easy +pattern so you might say if I keep on + + align:start position:0% +pattern so you might say if I keep on + + + align:start position:0% +pattern so you might say if I keep on +doing this I'm going to get 1+ 2+ 4 plus + + align:start position:0% +doing this I'm going to get 1+ 2+ 4 plus + + + align:start position:0% +doing this I'm going to get 1+ 2+ 4 plus +dot dot dot plus 2 to the I -1 + 2 to + + align:start position:0% +dot dot dot plus 2 to the I -1 + 2 to + + + align:start position:0% +dot dot dot plus 2 to the I -1 + 2 to +the i t nus + + align:start position:0% +the i t nus + + + align:start position:0% +the i t nus +i so got 2 3 TN minus 3 + + align:start position:0% +i so got 2 3 TN minus 3 + + + align:start position:0% +i so got 2 3 TN minus 3 +there and then I take this all the way + + align:start position:0% +there and then I take this all the way + + + align:start position:0% +there and then I take this all the way +down to I = nus 1 1 + 2 + + + align:start position:0% +down to I = nus 1 1 + 2 + + + + align:start position:0% +down to I = nus 1 1 + 2 + + + align:start position:0% + + + align:start position:0% ++ 2 to the nus 2 + 2 to the + + align:start position:0% ++ 2 to the nus 2 + 2 to the + + + align:start position:0% ++ 2 to the nus 2 + 2 to the +nus1 + + align:start position:0% + + + + align:start position:0% + +T1 and T1 is just + + align:start position:0% + + + + align:start position:0% + +one so I'm just getting the sum of the + + align:start position:0% +one so I'm just getting the sum of the + + + align:start position:0% +one so I'm just getting the sum of the +powers of two up to 2 the N minus one + + align:start position:0% +powers of two up to 2 the N minus one + + + align:start position:0% +powers of two up to 2 the N minus one +and we know what that is from + + align:start position:0% +and we know what that is from + + + align:start position:0% +and we know what that is from +last time for sure that's just 2 the N + + align:start position:0% +last time for sure that's just 2 the N + + + align:start position:0% +last time for sure that's just 2 the N +minus + + align:start position:0% +minus + + + align:start position:0% +minus +one all right so we've derived the + + align:start position:0% +one all right so we've derived the + + + align:start position:0% +one all right so we've derived the +answer with only a little bit of a we + + align:start position:0% +answer with only a little bit of a we + + + align:start position:0% +answer with only a little bit of a we +had to observe the pattern here which is + + align:start position:0% +had to observe the pattern here which is + + + align:start position:0% +had to observe the pattern here which is +often easy to do but now we've derived + + align:start position:0% +often easy to do but now we've derived + + + align:start position:0% +often easy to do but now we've derived +the answer now to be really safe we got + + align:start position:0% +the answer now to be really safe we got + + + align:start position:0% +the answer now to be really safe we got +to go back and still do verify just to + + align:start position:0% +to go back and still do verify just to + + + align:start position:0% +to go back and still do verify just to +make sure that we didn't make a mistake + + align:start position:0% +make sure that we didn't make a mistake + + + align:start position:0% +make sure that we didn't make a mistake +in how we you know did the derivation + + align:start position:0% +in how we you know did the derivation + + + align:start position:0% +in how we you know did the derivation +here + + align:start position:0% +here + + + align:start position:0% +here +okay any + + align:start position:0% +okay any + + + align:start position:0% +okay any +questions about that approach roach you + + align:start position:0% +questions about that approach roach you + + + align:start position:0% +questions about that approach roach you +just keep plugging it back into the + + align:start position:0% +just keep plugging it back into the + + + align:start position:0% +just keep plugging it back into the +recurrence look at the pattern you get + + align:start position:0% +recurrence look at the pattern you get + + + align:start position:0% +recurrence look at the pattern you get +and try to guess it from from that point + + align:start position:0% +and try to guess it from from that point + + + align:start position:0% +and try to guess it from from that point +and then + + align:start position:0% +and then + + + align:start position:0% +and then +solve all right let's do a little more + + align:start position:0% +solve all right let's do a little more + + + align:start position:0% +solve all right let's do a little more +interesting + + align:start position:0% +interesting + + + align:start position:0% +interesting +recurrence fact this is a fairly famous + + align:start position:0% +recurrence fact this is a fairly famous + + + align:start position:0% +recurrence fact this is a fairly famous +one that comes up in a well-known + + align:start position:0% +one that comes up in a well-known + + + align:start position:0% +one that comes up in a well-known +algorithm for sorting called merge sort + + align:start position:0% +algorithm for sorting called merge sort + + + align:start position:0% +algorithm for sorting called merge sort +this is an algorithm you'll look at in + + align:start position:0% +this is an algorithm you'll look at in + + + align:start position:0% +this is an algorithm you'll look at in +6046 one of the many sorting algorithms + + align:start position:0% +6046 one of the many sorting algorithms + + + align:start position:0% +6046 one of the many sorting algorithms +you'll study when you take an + + align:start position:0% +you'll study when you take an + + + align:start position:0% +you'll study when you take an +algorithm's class + + align:start position:0% + + + + align:start position:0% + +so you you give you're given n numbers + + align:start position:0% +so you you give you're given n numbers + + + align:start position:0% +so you you give you're given n numbers +and your task is to sort them put them + + align:start position:0% +and your task is to sort them put them + + + align:start position:0% +and your task is to sort them put them +in order and you're allowed to do + + align:start position:0% +in order and you're allowed to do + + + align:start position:0% +in order and you're allowed to do +comparisons between the numbers you + + align:start position:0% +comparisons between the numbers you + + + align:start position:0% +comparisons between the numbers you +could think of them as you got a A list + + align:start position:0% +could think of them as you got a A list + + + align:start position:0% +could think of them as you got a A list +of names putting them in alphabetical + + align:start position:0% +of names putting them in alphabetical + + + align:start position:0% +of names putting them in alphabetical +order uh how many comparisons do you + + align:start position:0% +order uh how many comparisons do you + + + align:start position:0% +order uh how many comparisons do you +have to do to make that + + align:start position:0% +have to do to make that + + + align:start position:0% +have to do to make that +happen and this is one way to do it + + align:start position:0% +happen and this is one way to do it + + + align:start position:0% +happen and this is one way to do it +that's very + + align:start position:0% +that's very + + + align:start position:0% +that's very +efficient so to sort n items in fact + + align:start position:0% +efficient so to sort n items in fact + + + align:start position:0% +efficient so to sort n items in fact +we're going to look at n being a power + + align:start position:0% +we're going to look at n being a power + + + align:start position:0% +we're going to look at n being a power +of two call the items X1 + + align:start position:0% +of two call the items X1 + + + align:start position:0% +of two call the items X1 +X2 + + align:start position:0% +X2 + + + align:start position:0% +X2 +xn n is going to be power of two to make + + align:start position:0% +xn n is going to be power of two to make + + + align:start position:0% +xn n is going to be power of two to make +it + + align:start position:0% +it + + + align:start position:0% +it +simple for + + align:start position:0% + + + + align:start position:0% + +now the first thing we're going to do is + + align:start position:0% +now the first thing we're going to do is + + + align:start position:0% +now the first thing we're going to do is +recursively sort the first half of the + + align:start position:0% +recursively sort the first half of the + + + align:start position:0% +recursively sort the first half of the +items and the second half + + align:start position:0% +items and the second half + + + align:start position:0% +items and the second half +so we use recursion to sort the first n/ + + align:start position:0% +so we use recursion to sort the first n/ + + + align:start position:0% +so we use recursion to sort the first n/ +two items and the last n/ two + + align:start position:0% + + + + align:start position:0% + +items and then we're going to merge + + align:start position:0% +items and then we're going to merge + + + align:start position:0% +items and then we're going to merge +those two sorted lists + + align:start position:0% + + + + align:start position:0% + +together so we're going to merge this + + align:start position:0% +together so we're going to merge this + + + align:start position:0% +together so we're going to merge this +list and that list so let's see how this + + align:start position:0% +list and that list so let's see how this + + + align:start position:0% +list and that list so let's see how this +works and figure out how many + + align:start position:0% +works and figure out how many + + + align:start position:0% +works and figure out how many +comparisons we have to do to sort the + + align:start position:0% + + + + align:start position:0% + +list for + + align:start position:0% +list for + + + align:start position:0% +list for +example let's say we're + + align:start position:0% +example let's say we're + + + align:start position:0% +example let's say we're +sorting this list + + align:start position:0% +sorting this list + + + align:start position:0% +sorting this list +10 7 + + align:start position:0% +10 7 + + + align:start position:0% +10 7 +23 5 2 4 three and nine so I've got + + align:start position:0% +23 5 2 4 three and nine so I've got + + + align:start position:0% +23 5 2 4 three and nine so I've got +eight numbers that I'm going to sort + + align:start position:0% +eight numbers that I'm going to sort + + + align:start position:0% +eight numbers that I'm going to sort +so the first step is to recursively sort + + align:start position:0% +so the first step is to recursively sort + + + align:start position:0% +so the first step is to recursively sort +that + + align:start position:0% +that + + + align:start position:0% +that +list and when I do that I produce I'm + + align:start position:0% +list and when I do that I produce I'm + + + align:start position:0% +list and when I do that I produce I'm +sorting 10 7 23 and + + align:start position:0% +sorting 10 7 23 and + + + align:start position:0% +sorting 10 7 23 and +five and that produces let's see I'm + + align:start position:0% +five and that produces let's see I'm + + + align:start position:0% +five and that produces let's see I'm +going to get 5 7 10 + + align:start position:0% + + + + align:start position:0% + +23 and then I recursively sort these + + align:start position:0% +23 and then I recursively sort these + + + align:start position:0% +23 and then I recursively sort these +guys + + align:start position:0% +guys + + + align:start position:0% +guys +and that + + align:start position:0% +and that + + + align:start position:0% +and that +produces 2 3 4 and + + align:start position:0% + + + + align:start position:0% + +nine I've done comparisons but haven't + + align:start position:0% +nine I've done comparisons but haven't + + + align:start position:0% +nine I've done comparisons but haven't +counted them because they're in the + + align:start position:0% +counted them because they're in the + + + align:start position:0% +counted them because they're in the +recursion now I'm going to use + + align:start position:0% +recursion now I'm going to use + + + align:start position:0% +recursion now I'm going to use +comparisons to merge the list and the + + align:start position:0% +comparisons to merge the list and the + + + align:start position:0% +comparisons to merge the list and the +way I'm going to do + + align:start position:0% + + + + align:start position:0% + +that is to look at the smallest item in + + align:start position:0% +that is to look at the smallest item in + + + align:start position:0% +that is to look at the smallest item in +each list and compare + + align:start position:0% +each list and compare + + + align:start position:0% +each list and compare +them because I know the smallest item + + align:start position:0% +them because I know the smallest item + + + align:start position:0% +them because I know the smallest item +overall is either this one or that one + + align:start position:0% +overall is either this one or that one + + + align:start position:0% +overall is either this one or that one +and when I compare two to five two is + + align:start position:0% +and when I compare two to five two is + + + align:start position:0% +and when I compare two to five two is +the smaller one so I start with two and + + align:start position:0% +the smaller one so I start with two and + + + align:start position:0% +the smaller one so I start with two and +I strike + + align:start position:0% +I strike + + + align:start position:0% +I strike +it what two items do I compare next to + + align:start position:0% +it what two items do I compare next to + + + align:start position:0% +it what two items do I compare next to +get the next smallest + + align:start position:0% +get the next smallest + + + align:start position:0% +get the next smallest +item five and three smallest remaining + + align:start position:0% +item five and three smallest remaining + + + align:start position:0% +item five and three smallest remaining +guys I get three scratch that guy and I + + align:start position:0% +guys I get three scratch that guy and I + + + align:start position:0% +guys I get three scratch that guy and I +compare five and four get four scratch + + align:start position:0% +compare five and four get four scratch + + + align:start position:0% +compare five and four get four scratch +him and five and + + align:start position:0% +him and five and + + + align:start position:0% +him and five and +nine five is the + + align:start position:0% +nine five is the + + + align:start position:0% +nine five is the +smallest seven and + + align:start position:0% +smallest seven and + + + align:start position:0% +smallest seven and +nine seven nine and + + align:start position:0% + + + + align:start position:0% + +10 and actually now I don't really have + + align:start position:0% +10 and actually now I don't really have + + + align:start position:0% +10 and actually now I don't really have +to do any more comparisons all I've got + + align:start position:0% +to do any more comparisons all I've got + + + align:start position:0% +to do any more comparisons all I've got +is one list left so I can + + align:start position:0% +is one list left so I can + + + align:start position:0% +is one list left so I can +just send these guys + + align:start position:0% +just send these guys + + + align:start position:0% +just send these guys +down and I produced a sorted + + align:start position:0% +down and I produced a sorted + + + align:start position:0% +down and I produced a sorted +list + + align:start position:0% +list + + + align:start position:0% +list +okay now + + align:start position:0% +okay now + + + align:start position:0% +okay now +how many comparisons do I have to do in + + align:start position:0% +how many comparisons do I have to do in + + + align:start position:0% +how many comparisons do I have to do in +the worst case if this is n/ two items + + align:start position:0% +the worst case if this is n/ two items + + + align:start position:0% +the worst case if this is n/ two items +here and this is n over2 + + align:start position:0% +here and this is n over2 + + + align:start position:0% +here and this is n over2 +here how many comparisons do I have to + + align:start position:0% +here how many comparisons do I have to + + + align:start position:0% +here how many comparisons do I have to +do to produce the N item sorted list + + align:start position:0% +do to produce the N item sorted list + + + align:start position:0% +do to produce the N item sorted list +after I have the Su list + + align:start position:0% +after I have the Su list + + + align:start position:0% +after I have the Su list +sorted what is it n very close n minus + + align:start position:0% +sorted what is it n very close n minus + + + align:start position:0% +sorted what is it n very close n minus +one is right okay because I do every + + align:start position:0% +one is right okay because I do every + + + align:start position:0% +one is right okay because I do every +time I do comparison I pull an item and + + align:start position:0% +time I do comparison I pull an item and + + + align:start position:0% +time I do comparison I pull an item and +stick it in the + + align:start position:0% +stick it in the + + + align:start position:0% +stick it in the +list but once I get down to the very + + align:start position:0% +list but once I get down to the very + + + align:start position:0% +list but once I get down to the very +last item just one guy sitting there I + + align:start position:0% +last item just one guy sitting there I + + + align:start position:0% +last item just one guy sitting there I +don't have to do a comparison it's just + + align:start position:0% +don't have to do a comparison it's just + + + align:start position:0% +don't have to do a comparison it's just +the last guy I know he's the + + align:start position:0% +the last guy I know he's the + + + align:start position:0% +the last guy I know he's the +largest so it it could go up to n minus + + align:start position:0% +largest so it it could go up to n minus + + + align:start position:0% +largest so it it could go up to n minus +one in the worst case in this situation + + align:start position:0% +one in the worst case in this situation + + + align:start position:0% +one in the worst case in this situation +I actually did n minus two because I was + + align:start position:0% +I actually did n minus two because I was + + + align:start position:0% +I actually did n minus two because I was +left with two guys at the end I just + + align:start position:0% +left with two guys at the end I just + + + align:start position:0% +left with two guys at the end I just +bring them down but it might have been + + align:start position:0% +bring them down but it might have been + + + align:start position:0% +bring them down but it might have been +that the next largest thing the 23 was + + align:start position:0% +that the next largest thing the 23 was + + + align:start position:0% +that the next largest thing the 23 was +here and then I would have done n minus + + align:start position:0% +here and then I would have done n minus + + + align:start position:0% +here and then I would have done n minus +one + + align:start position:0% +one + + + align:start position:0% +one +any + + align:start position:0% +any + + + align:start position:0% +any +questions + + align:start position:0% + + + + align:start position:0% + +yeah otherist that make it faster well + + align:start position:0% +yeah otherist that make it faster well + + + align:start position:0% +yeah otherist that make it faster well +that's what's going to happen with the + + align:start position:0% +that's what's going to happen with the + + + align:start position:0% +that's what's going to happen with the +recursion because the first thing we're + + align:start position:0% +recursion because the first thing we're + + + align:start position:0% +recursion because the first thing we're +going to do is when we unfold the + + align:start position:0% +going to do is when we unfold the + + + align:start position:0% +going to do is when we unfold the +recursion is you're going to take the + + align:start position:0% +recursion is you're going to take the + + + align:start position:0% +recursion is you're going to take the +first half split it in half recursively + + align:start position:0% +first half split it in half recursively + + + align:start position:0% +first half split it in half recursively +sort them and then merge them so the + + align:start position:0% +sort them and then merge them so the + + + align:start position:0% +sort them and then merge them so the +answer is that's going to happen but + + align:start position:0% +answer is that's going to happen but + + + align:start position:0% +answer is that's going to happen but +we're sort of going to hide it by the + + align:start position:0% +we're sort of going to hide it by the + + + align:start position:0% +we're sort of going to hide it by the +recursion all right you didn't see me + + align:start position:0% +recursion all right you didn't see me + + + align:start position:0% +recursion all right you didn't see me +produ + + align:start position:0% +produ + + + align:start position:0% +produ +that sorted list but I would have done + + align:start position:0% +that sorted list but I would have done + + + align:start position:0% +that sorted list but I would have done +it by taking 10 and seven sorting them 5 + + align:start position:0% +it by taking 10 and seven sorting them 5 + + + align:start position:0% +it by taking 10 and seven sorting them 5 +and 23 and sorting them and then merging + + align:start position:0% +and 23 and sorting them and then merging + + + align:start position:0% +and 23 and sorting them and then merging +them okay any other + + align:start position:0% + + + + align:start position:0% + +questions all right well let's set up + + align:start position:0% +questions all right well let's set up + + + align:start position:0% +questions all right well let's set up +the recursion to count how many + + align:start position:0% +the recursion to count how many + + + align:start position:0% +the recursion to count how many +comparisons are needed for the whole + + align:start position:0% +comparisons are needed for the whole + + + align:start position:0% +comparisons are needed for the whole +thing not just the last merge phase + + align:start position:0% + + + + align:start position:0% + +all right so let's + + align:start position:0% + + + + align:start position:0% + +define and instead of T subn I'm going + + align:start position:0% +define and instead of T subn I'm going + + + align:start position:0% +define and instead of T subn I'm going +to write T of n as a function makes no + + align:start position:0% +to write T of n as a function makes no + + + align:start position:0% +to write T of n as a function makes no +difference but you'll see people do + + align:start position:0% +difference but you'll see people do + + + align:start position:0% +difference but you'll see people do +recurrences both ways T of n or T + + align:start position:0% +recurrences both ways T of n or T + + + align:start position:0% +recurrences both ways T of n or T +subn it's going to be the number of + + align:start position:0% + + + + align:start position:0% + +comparisons used by merge sort to sort + + align:start position:0% +comparisons used by merge sort to sort + + + align:start position:0% +comparisons used by merge sort to sort +n + + align:start position:0% +n + + + align:start position:0% +n +numbers in the worst case worst + + align:start position:0% + + + + align:start position:0% + +case all right so we already know that + + align:start position:0% + + + + align:start position:0% + +merging takes n minus one + + align:start position:0% + + + + align:start position:0% + +comparisons in the worst + + align:start position:0% +comparisons in the worst + + + align:start position:0% +comparisons in the worst +case and you always want to prepare for + + align:start position:0% +case and you always want to prepare for + + + align:start position:0% +case and you always want to prepare for +the worst case + + align:start position:0% + + + + align:start position:0% + +how many comparisons are + + align:start position:0% +how many comparisons are + + + align:start position:0% +how many comparisons are +used in the recursive steps to sort this + + align:start position:0% +used in the recursive steps to sort this + + + align:start position:0% +used in the recursive steps to sort this +list and to sort that list in + + align:start position:0% +list and to sort that list in + + + align:start position:0% +list and to sort that list in +general TN over + + align:start position:0% +general TN over + + + align:start position:0% +general TN over +two to do this + + align:start position:0% +two to do this + + + align:start position:0% +two to do this +list times two because you got two lists + + align:start position:0% +list times two because you got two lists + + + align:start position:0% +list times two because you got two lists +of size n/ two two sub problems of size + + align:start position:0% +of size n/ two two sub problems of size + + + align:start position:0% +of size n/ two two sub problems of size +n over two each takes T of n + + align:start position:0% +n over two each takes T of n + + + align:start position:0% +n over two each takes T of n +/2 all right so you've got 2 TN /2 + + align:start position:0% + + + + align:start position:0% + +comparisons for the recursive + + align:start position:0% + + + + align:start position:0% + +sorting all right that means + + align:start position:0% +sorting all right that means + + + align:start position:0% +sorting all right that means +that t of + + align:start position:0% +that t of + + + align:start position:0% +that t of +n equals 2 T of n + + align:start position:0% +n equals 2 T of n + + + align:start position:0% +n equals 2 T of n +/2 plus n minus + + align:start position:0% +/2 plus n minus + + + align:start position:0% +/2 plus n minus +one and we should say what T of one is + + align:start position:0% +one and we should say what T of one is + + + align:start position:0% +one and we should say what T of one is +what's that + + align:start position:0% +what's that + + + align:start position:0% +what's that +what's the time to + + align:start position:0% +what's the time to + + + align:start position:0% +what's the time to +sort zero you don't do any comparisons + + align:start position:0% +sort zero you don't do any comparisons + + + align:start position:0% +sort zero you don't do any comparisons +if there's one item so we'll set that as + + align:start position:0% +if there's one item so we'll set that as + + + align:start position:0% +if there's one item so we'll set that as +our base + + align:start position:0% + + + + align:start position:0% + +case all right so let's find the + + align:start position:0% +case all right so let's find the + + + align:start position:0% +case all right so let's find the +answer so the first thing to always do + + align:start position:0% +answer so the first thing to always do + + + align:start position:0% +answer so the first thing to always do +when you see a + + align:start position:0% +when you see a + + + align:start position:0% +when you see a +recurrence is + + align:start position:0% +recurrence is + + + align:start position:0% +recurrence is +to take a few values compute a few + + align:start position:0% +to take a few values compute a few + + + align:start position:0% +to take a few values compute a few +values and try to guess the + + align:start position:0% +values and try to guess the + + + align:start position:0% +values and try to guess the +answer so what's T of + + align:start position:0% + + + + align:start position:0% + +two one plug it in I get 2 T of 1 T of 1 + + align:start position:0% +two one plug it in I get 2 T of 1 T of 1 + + + align:start position:0% +two one plug it in I get 2 T of 1 T of 1 +zero plus 2 minus one that's + + align:start position:0% +zero plus 2 minus one that's + + + align:start position:0% +zero plus 2 minus one that's +one all right what's T of and we're only + + align:start position:0% +one all right what's T of and we're only + + + align:start position:0% +one all right what's T of and we're only +doing powers of four here sorry powers + + align:start position:0% +doing powers of four here sorry powers + + + align:start position:0% +doing powers of four here sorry powers +of two so I go to T of four next what's + + align:start position:0% +of two so I go to T of four next what's + + + align:start position:0% +of two so I go to T of four next what's +T of + + align:start position:0% + + + + align:start position:0% + +four + + align:start position:0% +four + + + align:start position:0% +four +five right because I've got double this + + align:start position:0% +five right because I've got double this + + + align:start position:0% +five right because I've got double this +is two plus four - one that's adding + + align:start position:0% +is two plus four - one that's adding + + + align:start position:0% +is two plus four - one that's adding +three so I get + + align:start position:0% +three so I get + + + align:start position:0% +three so I get +five all right let's look at T of + + align:start position:0% +five all right let's look at T of + + + align:start position:0% +five all right let's look at T of +8 that's twice + + align:start position:0% +8 that's twice + + + align:start position:0% +8 that's twice +5+ 8 - + + align:start position:0% + + + + align:start position:0% + + + align:start position:0% + + + + align:start position:0% + +17 not so clear what to guess + + align:start position:0% +17 not so clear what to guess + + + align:start position:0% +17 not so clear what to guess +here we can try one + + align:start position:0% +here we can try one + + + align:start position:0% +here we can try one +more T is 16 = 2 * 17 + 16 - 1 + + align:start position:0% +more T is 16 = 2 * 17 + 16 - 1 + + + align:start position:0% +more T is 16 = 2 * 17 + 16 - 1 += + + align:start position:0% += + + + align:start position:0% += +34 and + + align:start position:0% +34 and + + + align:start position:0% +34 and +15 is 49 is that + + align:start position:0% +15 is 49 is that + + + align:start position:0% +15 is 49 is that +right 34 and + + align:start position:0% + + + + align:start position:0% + +15 any any + + align:start position:0% + + + + align:start position:0% + +guesses this one's you're not going to + + align:start position:0% +guesses this one's you're not going to + + + align:start position:0% +guesses this one's you're not going to +guess this that's not going to work and + + align:start position:0% +guess this that's not going to work and + + + align:start position:0% +guess this that's not going to work and +that happens Miracle could happen you + + align:start position:0% +that happens Miracle could happen you + + + align:start position:0% +that happens Miracle could happen you +get a Divine insight and guess it but I + + align:start position:0% +get a Divine insight and guess it but I + + + align:start position:0% +get a Divine insight and guess it but I +think it's not likely + + align:start position:0% +think it's not likely + + + align:start position:0% +think it's not likely +all right so let's go to plug and + + align:start position:0% +all right so let's go to plug and + + + align:start position:0% +all right so let's go to plug and +chug see if that + + align:start position:0% + + + + align:start position:0% + +works all right so now plug and + + align:start position:0% + + + + align:start position:0% + +chug all right so we write down T of n + + align:start position:0% +chug all right so we write down T of n + + + align:start position:0% +chug all right so we write down T of n +is and you always write the recurrent + + align:start position:0% +is and you always write the recurrent + + + align:start position:0% +is and you always write the recurrent +part last for plug and chug to keep it + + align:start position:0% +part last for plug and chug to keep it + + + align:start position:0% +part last for plug and chug to keep it +simpler 2 T of N + + align:start position:0% +simpler 2 T of N + + + align:start position:0% +simpler 2 T of N +/2 and then I substitute I plug in for T + + align:start position:0% +/2 and then I substitute I plug in for T + + + align:start position:0% +/2 and then I substitute I plug in for T +of n + + align:start position:0% +of n + + + align:start position:0% +of n +/2 so I have n minus1 + + + align:start position:0% +/2 so I have n minus1 + + + + align:start position:0% +/2 so I have n minus1 + +2 N / 2 - 1 + 2 T of n + + align:start position:0% +2 N / 2 - 1 + 2 T of n + + + align:start position:0% +2 N / 2 - 1 + 2 T of n +over4 then I + + align:start position:0% +over4 then I + + + align:start position:0% +over4 then I +chug so I have n minus one plus that's + + align:start position:0% +chug so I have n minus one plus that's + + + align:start position:0% +chug so I have n minus one plus that's +n minus 2 + + align:start position:0% +n minus 2 + + + align:start position:0% +n minus 2 +plus 4 TN over + + align:start position:0% + + + + align:start position:0% + +4 all right then we'll plug in + + align:start position:0% + + + + align:start position:0% + +here and I get N over4 - + + align:start position:0% +here and I get N over4 - + + + align:start position:0% +here and I get N over4 - +1+ 4 TN over + + align:start position:0% + + + + align:start position:0% + +8 and now we + + align:start position:0% + + + + align:start position:0% + +chug that's an n here minus a + + align:start position:0% + + + + align:start position:0% + +four I did something wrong I plugged in + + align:start position:0% +four I did something wrong I plugged in + + + align:start position:0% +four I did something wrong I plugged in +that should be two 4 * 2 is 8 TN over + + align:start position:0% + + + + align:start position:0% + +8 all right can you start to guess the + + align:start position:0% +8 all right can you start to guess the + + + align:start position:0% +8 all right can you start to guess the +pattern here + + align:start position:0% +pattern here + + + align:start position:0% +pattern here +maybe you know we probably should do one + + align:start position:0% +maybe you know we probably should do one + + + align:start position:0% +maybe you know we probably should do one +more to be safe but you got an N minus + + align:start position:0% +more to be safe but you got an N minus + + + align:start position:0% +more to be safe but you got an N minus +one plus an nus 2 plus an nus 4 and if + + align:start position:0% +one plus an nus 2 plus an nus 4 and if + + + align:start position:0% +one plus an nus 2 plus an nus 4 and if +we do one more what's the term going to + + align:start position:0% +we do one more what's the term going to + + + align:start position:0% +we do one more what's the term going to +be n minus 8 and this is looking pretty + + align:start position:0% +be n minus 8 and this is looking pretty + + + align:start position:0% +be n minus 8 and this is looking pretty +simple so we could guess now that the + + align:start position:0% +simple so we could guess now that the + + + align:start position:0% +simple so we could guess now that the +pattern + + align:start position:0% + + + + align:start position:0% + +is n -1 + N - 2 + N - 4 all the way out + + align:start position:0% +is n -1 + N - 2 + N - 4 all the way out + + + align:start position:0% +is n -1 + N - 2 + N - 4 all the way out +to plus n minus 2 the I + + align:start position:0% +to plus n minus 2 the I + + + align:start position:0% +to plus n minus 2 the I +-1 + 2 to the i t n over 2 the + + align:start position:0% +-1 + 2 to the i t n over 2 the + + + align:start position:0% +-1 + 2 to the i t n over 2 the +I and now we go all the way down where I + + align:start position:0% +I and now we go all the way down where I + + + align:start position:0% +I and now we go all the way down where I +equal log n base + + align:start position:0% +equal log n base + + + align:start position:0% +equal log n base +2 all right and and see what we + + align:start position:0% + + + + align:start position:0% + +get 1 + N - 2 plus all the way down N - + + align:start position:0% +get 1 + N - 2 plus all the way down N - + + + align:start position:0% +get 1 + N - 2 plus all the way down N - +2 to the log n + + align:start position:0% +2 to the log n + + + align:start position:0% +2 to the log n +-1 plus 2 the log + + align:start position:0% +-1 plus 2 the log + + + align:start position:0% +-1 plus 2 the log +n t of + + align:start position:0% +n t of + + + align:start position:0% +n t of +1 what's T of + + align:start position:0% +1 what's T of + + + align:start position:0% +1 what's T of +one zero that's nice that goes away + + align:start position:0% +one zero that's nice that goes away + + + align:start position:0% +one zero that's nice that goes away +all right so this is not looking so bad + + align:start position:0% +all right so this is not looking so bad + + + align:start position:0% +all right so this is not looking so bad +this equals the + + align:start position:0% +this equals the + + + align:start position:0% +this equals the +sum I equal 0 to log + + align:start position:0% +sum I equal 0 to log + + + align:start position:0% +sum I equal 0 to log +nus1 of nus 2 the + + align:start position:0% + + + + align:start position:0% + +I all right and this will be good + + align:start position:0% +I all right and this will be good + + + align:start position:0% +I all right and this will be good +practice maybe for to get towards the + + align:start position:0% +practice maybe for to get towards the + + + align:start position:0% +practice maybe for to get towards the +test well I can split that sum + + align:start position:0% +test well I can split that sum + + + align:start position:0% +test well I can split that sum +up I = 0 to log n + + align:start position:0% +up I = 0 to log n + + + align:start position:0% +up I = 0 to log n +minus1 of n minus the sum i = 0 Log n + + align:start position:0% +minus1 of n minus the sum i = 0 Log n + + + align:start position:0% +minus1 of n minus the sum i = 0 Log n +minus one of 2 to the + + align:start position:0% + + + + align:start position:0% + +I well this is easy I'm just adding n up + + align:start position:0% +I well this is easy I'm just adding n up + + + align:start position:0% +I well this is easy I'm just adding n up +a total of log n times so I have n log + + align:start position:0% + + + + align:start position:0% + +n this is just summing the powers of two + + align:start position:0% +n this is just summing the powers of two + + + align:start position:0% +n this is just summing the powers of two +which we know to do know how to do so + + align:start position:0% +which we know to do know how to do so + + + align:start position:0% +which we know to do know how to do so +that's going to be 2 the log + + align:start position:0% +that's going to be 2 the log + + + align:start position:0% +that's going to be 2 the log +n minus + + align:start position:0% +n minus + + + align:start position:0% +n minus +one and so we get our answer + + align:start position:0% +one and so we get our answer + + + align:start position:0% +one and so we get our answer +is n log + + align:start position:0% +is n log + + + align:start position:0% +is n log +n minus 2 the log n is just n minus + + align:start position:0% +n minus 2 the log n is just n minus + + + align:start position:0% +n minus 2 the log n is just n minus +minus one is+ + + align:start position:0% +minus one is+ + + + align:start position:0% +minus one is+ +one well we derived an + + align:start position:0% +one well we derived an + + + align:start position:0% +one well we derived an +answer let's see let's just go back and + + align:start position:0% +answer let's see let's just go back and + + + align:start position:0% +answer let's see let's just go back and +check some of the + + align:start position:0% +check some of the + + + align:start position:0% +check some of the +values uh n equals 1 that's zero and I + + align:start position:0% +values uh n equals 1 that's zero and I + + + align:start position:0% +values uh n equals 1 that's zero and I +get one minus one it + + align:start position:0% +get one minus one it + + + align:start position:0% +get one minus one it +works n = + + align:start position:0% +works n = + + + align:start position:0% +works n = +2 2 log 2 is 2- 2 + + + align:start position:0% +2 2 log 2 is 2- 2 + + + + align:start position:0% +2 2 log 2 is 2- 2 + +1 Works plug in four I get 4 log 4 is 8 + + align:start position:0% +1 Works plug in four I get 4 log 4 is 8 + + + align:start position:0% +1 Works plug in four I get 4 log 4 is 8 +- 4 is four plus 1 is five so it works + + align:start position:0% +- 4 is four plus 1 is five so it works + + + align:start position:0% +- 4 is four plus 1 is five so it works +all right for those examples now to be + + align:start position:0% +all right for those examples now to be + + + align:start position:0% +all right for those examples now to be +really careful we should prove it by + + align:start position:0% +really careful we should prove it by + + + align:start position:0% +really careful we should prove it by +induction because when you do enough of + + align:start position:0% +induction because when you do enough of + + + align:start position:0% +induction because when you do enough of +these equations you make mistakes like I + + align:start position:0% +these equations you make mistakes like I + + + align:start position:0% +these equations you make mistakes like I +invariably do even up here and even + + align:start position:0% +invariably do even up here and even + + + align:start position:0% +invariably do even up here and even +though it's written down here I'll make + + align:start position:0% +though it's written down here I'll make + + + align:start position:0% +though it's written down here I'll make +mistakes writing it on the board and so + + align:start position:0% +mistakes writing it on the board and so + + + align:start position:0% +mistakes writing it on the board and so +you want to check you know by induction + + align:start position:0% + + + + align:start position:0% + +uh okay so this is the answer this is + + align:start position:0% +uh okay so this is the answer this is + + + align:start position:0% +uh okay so this is the answer this is +how many comparisons are done in merge + + align:start position:0% +how many comparisons are done in merge + + + align:start position:0% +how many comparisons are done in merge +sort and the nice thing is this is + + align:start position:0% +sort and the nice thing is this is + + + align:start position:0% +sort and the nice thing is this is +growing nearly linearly it grows as n + + align:start position:0% +growing nearly linearly it grows as n + + + align:start position:0% +growing nearly linearly it grows as n +log n and that's why this algorithm is + + align:start position:0% +log n and that's why this algorithm is + + + align:start position:0% +log n and that's why this algorithm is +used a lot in practice much better than + + align:start position:0% +used a lot in practice much better than + + + align:start position:0% +used a lot in practice much better than +comparing every item to every other item + + align:start position:0% +comparing every item to every other item + + + align:start position:0% +comparing every item to every other item +which would be more like N squared steps + + align:start position:0% +which would be more like N squared steps + + + align:start position:0% +which would be more like N squared steps +right so much better than a naive + + align:start position:0% +right so much better than a naive + + + align:start position:0% +right so much better than a naive +sorting + + align:start position:0% +sorting + + + align:start position:0% +sorting +algorithm any + + align:start position:0% +algorithm any + + + align:start position:0% +algorithm any +questions about what we did there + + align:start position:0% +questions about what we did there + + + align:start position:0% +questions about what we did there +you know just one rule of thumb when + + align:start position:0% +you know just one rule of thumb when + + + align:start position:0% +you know just one rule of thumb when +you're doing the plug and + + align:start position:0% +you're doing the plug and + + + align:start position:0% +you're doing the plug and +chug notice that I didn't try to + + align:start position:0% +chug notice that I didn't try to + + + align:start position:0% +chug notice that I didn't try to +collapse terms along the + + align:start position:0% +collapse terms along the + + + align:start position:0% +collapse terms along the +way it makes it easier sometimes to see + + align:start position:0% +way it makes it easier sometimes to see + + + align:start position:0% +way it makes it easier sometimes to see +the pattern I left it as n minus1 plus n + + align:start position:0% +the pattern I left it as n minus1 plus n + + + align:start position:0% +the pattern I left it as n minus1 plus n +min-2 and then plus n minus 4 rather + + align:start position:0% +min-2 and then plus n minus 4 rather + + + align:start position:0% +min-2 and then plus n minus 4 rather +than saying oh this is 3 n minus 7 which + + align:start position:0% +than saying oh this is 3 n minus 7 which + + + align:start position:0% +than saying oh this is 3 n minus 7 which +might have made it harder to guess the + + align:start position:0% +might have made it harder to guess the + + + align:start position:0% +might have made it harder to guess the +pattern so you don't always when you're + + align:start position:0% +pattern so you don't always when you're + + + align:start position:0% +pattern so you don't always when you're +doing the chugging collapse everything + + align:start position:0% +doing the chugging collapse everything + + + align:start position:0% +doing the chugging collapse everything +down you want to try and see if there's + + align:start position:0% +down you want to try and see if there's + + + align:start position:0% +down you want to try and see if there's +some because this is the amount of work + + align:start position:0% +some because this is the amount of work + + + align:start position:0% +some because this is the amount of work +done at each step and you want to see if + + align:start position:0% +done at each step and you want to see if + + + align:start position:0% +done at each step and you want to see if +you can see a pattern in + + align:start position:0% +you can see a pattern in + + + align:start position:0% +you can see a pattern in +that + + align:start position:0% +that + + + align:start position:0% +that +okay all right so let's write down our + + align:start position:0% +okay all right so let's write down our + + + align:start position:0% +okay all right so let's write down our +two recurrences + + align:start position:0% +two recurrences + + + align:start position:0% +two recurrences +and sort of compare + + align:start position:0% + + + + align:start position:0% + +them so first we did towers of Hanoi + + align:start position:0% +them so first we did towers of Hanoi + + + align:start position:0% +them so first we did towers of Hanoi +which was T of Nal 2 2 T of n minus1 + 1 + + align:start position:0% +which was T of Nal 2 2 T of n minus1 + 1 + + + align:start position:0% +which was T of Nal 2 2 T of n minus1 + 1 +and the answer + + align:start position:0% +and the answer + + + align:start position:0% +and the answer +was T of n is Tilda 2 the N it was + + align:start position:0% +was T of n is Tilda 2 the N it was + + + align:start position:0% +was T of n is Tilda 2 the N it was +actually 2 the N minus + + align:start position:0% +actually 2 the N minus + + + align:start position:0% +actually 2 the N minus +one then we did merge sort which is T of + + align:start position:0% +one then we did merge sort which is T of + + + align:start position:0% +one then we did merge sort which is T of +n equals 2 T of n / + + align:start position:0% +n equals 2 T of n / + + + align:start position:0% +n equals 2 T of n / +2 right difference there plus n + + align:start position:0% +2 right difference there plus n + + + align:start position:0% +2 right difference there plus n +minus1 and now the answer was T of n + + align:start position:0% +minus1 and now the answer was T of n + + + align:start position:0% +minus1 and now the answer was T of n +what's the till for this one for merge + + align:start position:0% +what's the till for this one for merge + + + align:start position:0% +what's the till for this one for merge +sort n log n yeah I can I can forget the + + align:start position:0% +sort n log n yeah I can I can forget the + + + align:start position:0% +sort n log n yeah I can I can forget the +rest if I'm doing the TOA n log + + align:start position:0% + + + + align:start position:0% + +n + + align:start position:0% +n + + + align:start position:0% +n +wow these are pretty different answers + + align:start position:0% +wow these are pretty different answers + + + align:start position:0% +wow these are pretty different answers +right this one's nearly linear that + + align:start position:0% +right this one's nearly linear that + + + align:start position:0% +right this one's nearly linear that +one's + + align:start position:0% +one's + + + align:start position:0% +one's +exponential the recurrences looked + + align:start position:0% +exponential the recurrences looked + + + align:start position:0% +exponential the recurrences looked +pretty + + align:start position:0% +pretty + + + align:start position:0% +pretty +similar in fact this one sort of looks + + align:start position:0% +similar in fact this one sort of looks + + + align:start position:0% +similar in fact this one sort of looks +worse because I'm adding in N minus one + + align:start position:0% +worse because I'm adding in N minus one + + + align:start position:0% +worse because I'm adding in N minus one +every time instead of one but the answer + + align:start position:0% +every time instead of one but the answer + + + align:start position:0% +every time instead of one but the answer +is a lot better lot + + align:start position:0% +is a lot better lot + + + align:start position:0% +is a lot better lot +smaller what's the critical difference + + align:start position:0% +smaller what's the critical difference + + + align:start position:0% +smaller what's the critical difference +between these + + align:start position:0% +between these + + + align:start position:0% +between these +recurrences + + align:start position:0% + + + + align:start position:0% + +yeah you dropping the argument of t a + + align:start position:0% +yeah you dropping the argument of t a + + + align:start position:0% +yeah you dropping the argument of t a +lot faster you're cutting it in half + + align:start position:0% +lot faster you're cutting it in half + + + align:start position:0% +lot faster you're cutting it in half +every time instead of subtracting one + + align:start position:0% +every time instead of subtracting one + + + align:start position:0% +every time instead of subtracting one +right so go away faster that's right + + align:start position:0% +right so go away faster that's right + + + align:start position:0% +right so go away faster that's right +here I've got two problems of size one + + align:start position:0% +here I've got two problems of size one + + + align:start position:0% +here I've got two problems of size one +less here I've got two problem of half + + align:start position:0% +less here I've got two problem of half + + + align:start position:0% +less here I've got two problem of half +the + + align:start position:0% +the + + + align:start position:0% +the +size and that makes an enormous + + align:start position:0% +size and that makes an enormous + + + align:start position:0% +size and that makes an enormous +difference in the answer even though I'm + + align:start position:0% +difference in the answer even though I'm + + + align:start position:0% +difference in the answer even though I'm +doing more work after I cut you know did + + align:start position:0% +doing more work after I cut you know did + + + align:start position:0% +doing more work after I cut you know did +the recursive problems much faster + + align:start position:0% +the recursive problems much faster + + + align:start position:0% +the recursive problems much faster +running time or answer if these are + + align:start position:0% +running time or answer if these are + + + align:start position:0% +running time or answer if these are +algorithms that I'm I'm + + align:start position:0% +algorithms that I'm I'm + + + align:start position:0% +algorithms that I'm I'm +analyzing all right uh in fact let's + + align:start position:0% +analyzing all right uh in fact let's + + + align:start position:0% +analyzing all right uh in fact let's +take a look at what happens if + + align:start position:0% +take a look at what happens if + + + align:start position:0% +take a look at what happens if +I didn't use that n minus one I just put + + align:start position:0% +I didn't use that n minus one I just put + + + align:start position:0% +I didn't use that n minus one I just put +a one there let's see what impact that n + + align:start position:0% +a one there let's see what impact that n + + + align:start position:0% +a one there let's see what impact that n +minus one had + + align:start position:0% +minus one had + + + align:start position:0% +minus one had +had uh so let's do the + + align:start position:0% +had uh so let's do the + + + align:start position:0% +had uh so let's do the +following + + align:start position:0% +following + + + align:start position:0% +following +recurrence this one's going to be a + + align:start position:0% +recurrence this one's going to be a + + + align:start position:0% +recurrence this one's going to be a +little bit + + align:start position:0% +little bit + + + align:start position:0% +little bit +different because I'm not going to stick + + align:start position:0% +different because I'm not going to stick + + + align:start position:0% +different because I'm not going to stick +to powers of two I'm going to get a + + align:start position:0% +to powers of two I'm going to get a + + + align:start position:0% +to powers of two I'm going to get a +little Messier because that often + + align:start position:0% +little Messier because that often + + + align:start position:0% +little Messier because that often +happens in reality and I'm going to + + align:start position:0% +happens in reality and I'm going to + + + align:start position:0% +happens in reality and I'm going to +Define s of one is zero s of + + align:start position:0% +Define s of one is zero s of + + + align:start position:0% +Define s of one is zero s of +n is s of the floor function of n/2 + + align:start position:0% + + + + align:start position:0% + +plus s of the ceiling function of n + + align:start position:0% +plus s of the ceiling function of n + + + align:start position:0% +plus s of the ceiling function of n +/2 plus + + align:start position:0% + + + + align:start position:0% + +one now the ceiling function means the + + align:start position:0% +one now the ceiling function means the + + + align:start position:0% +one now the ceiling function means the +smallest integer that's at least that + + align:start position:0% +smallest integer that's at least that + + + align:start position:0% +smallest integer that's at least that +big so you're sort of rounding up to the + + align:start position:0% +big so you're sort of rounding up to the + + + align:start position:0% +big so you're sort of rounding up to the +next integer + + align:start position:0% + + + + align:start position:0% + +and the floor function means you're + + align:start position:0% +and the floor function means you're + + + align:start position:0% +and the floor function means you're +rounding down to the next integer so + + align:start position:0% +rounding down to the next integer so + + + align:start position:0% +rounding down to the next integer so +it's the biggest + + align:start position:0% + + + + align:start position:0% + +integer less than equal to + + align:start position:0% +integer less than equal to + + + align:start position:0% +integer less than equal to +n/2 all right now if we had just powers + + align:start position:0% +n/2 all right now if we had just powers + + + align:start position:0% +n/2 all right now if we had just powers +of two this would be much easier to + + align:start position:0% +of two this would be much easier to + + + align:start position:0% +of two this would be much easier to +write it would just be snal 2 SN + + align:start position:0% +write it would just be snal 2 SN + + + align:start position:0% +write it would just be snal 2 SN +/2 + 1 all right so it's analogous to + + align:start position:0% +/2 + 1 all right so it's analogous to + + + align:start position:0% +/2 + 1 all right so it's analogous to +what we're doing up there where we're + + align:start position:0% +what we're doing up there where we're + + + align:start position:0% +what we're doing up there where we're +just adding one instead of n minus one + + align:start position:0% +just adding one instead of n minus one + + + align:start position:0% +just adding one instead of n minus one +but I'm being careful now I'm going to + + align:start position:0% +but I'm being careful now I'm going to + + + align:start position:0% +but I'm being careful now I'm going to +make this recurrence work for + + align:start position:0% +make this recurrence work for + + + align:start position:0% +make this recurrence work for +all natural numbers because sometimes in + + align:start position:0% +all natural numbers because sometimes in + + + align:start position:0% +all natural numbers because sometimes in +reality you're dealing with non-p powers + + align:start position:0% +reality you're dealing with non-p powers + + + align:start position:0% +reality you're dealing with non-p powers +of + + align:start position:0% + + + + align:start position:0% + +two uh all right let's see if we can + + align:start position:0% +two uh all right let's see if we can + + + align:start position:0% +two uh all right let's see if we can +solve + + align:start position:0% +solve + + + align:start position:0% +solve +this what's the first thing to try to + + align:start position:0% +this what's the first thing to try to + + + align:start position:0% +this what's the first thing to try to +solve this what do you + + align:start position:0% + + + + align:start position:0% + +do what's the first step when you get a + + align:start position:0% +do what's the first step when you get a + + + align:start position:0% +do what's the first step when you get a +recurrence you try to + + align:start position:0% + + + + align:start position:0% + +solve all right what method should you + + align:start position:0% +solve all right what method should you + + + align:start position:0% +solve all right what method should you +try guess and to guess well you got to + + align:start position:0% +try guess and to guess well you got to + + + align:start position:0% +try guess and to guess well you got to +plug some values in all right sort of + + align:start position:0% +plug some values in all right sort of + + + align:start position:0% +plug some values in all right sort of +hard to guess I mean I don't know + + align:start position:0% +hard to guess I mean I don't know + + + align:start position:0% +hard to guess I mean I don't know +looking at that I guessing nothing comes + + align:start position:0% +looking at that I guessing nothing comes + + + align:start position:0% +looking at that I guessing nothing comes +to mind other than Panic looking at that + + align:start position:0% +to mind other than Panic looking at that + + + align:start position:0% +to mind other than Panic looking at that +all right but if we plug in some values + + align:start position:0% +all right but if we plug in some values + + + align:start position:0% +all right but if we plug in some values +then maybe it won't be so bad so we got + + align:start position:0% +then maybe it won't be so bad so we got + + + align:start position:0% +then maybe it won't be so bad so we got +S1 equals zero what's S2 + + align:start position:0% + + + + align:start position:0% + +this not three because this is 2 over + + align:start position:0% +this not three because this is 2 over + + + align:start position:0% +this not three because this is 2 over +two is one floor of one is one s of one + + align:start position:0% +two is one floor of one is one s of one + + + align:start position:0% +two is one floor of one is one s of one +is + + align:start position:0% +is + + + align:start position:0% +is +zero got ceiling of one is one because + + align:start position:0% +zero got ceiling of one is one because + + + align:start position:0% +zero got ceiling of one is one because +it's an integer s of one is zero plus + + align:start position:0% +it's an integer s of one is zero plus + + + align:start position:0% +it's an integer s of one is zero plus +one so s of two is + + align:start position:0% +one so s of two is + + + align:start position:0% +one so s of two is +one what's s of three yikes all right 3 + + align:start position:0% +one what's s of three yikes all right 3 + + + align:start position:0% +one what's s of three yikes all right 3 +over 2 is 1 and A2 what's the floor of + + align:start position:0% +over 2 is 1 and A2 what's the floor of + + + align:start position:0% +over 2 is 1 and A2 what's the floor of +one one and a half One S of one is zero + + align:start position:0% +one one and a half One S of one is zero + + + align:start position:0% +one one and a half One S of one is zero +that's gone what's the ceiling of one + + align:start position:0% +that's gone what's the ceiling of one + + + align:start position:0% +that's gone what's the ceiling of one +and a + + align:start position:0% +and a + + + align:start position:0% +and a +half s of two is + + align:start position:0% +half s of two is + + + align:start position:0% +half s of two is +one plus one what's the answer for S of + + align:start position:0% + + + + align:start position:0% + +three two right because I've got zero + + align:start position:0% +three two right because I've got zero + + + align:start position:0% +three two right because I've got zero +one and + + align:start position:0% +one and + + + align:start position:0% +one and +one all right s of four this one's easy + + align:start position:0% +one all right s of four this one's easy + + + align:start position:0% +one all right s of four this one's easy +because it's + + align:start position:0% +because it's + + + align:start position:0% +because it's +even I get S of two which is 1 plus s of + + align:start position:0% +even I get S of two which is 1 plus s of + + + align:start position:0% +even I get S of two which is 1 plus s of +2 which is 1 + 1 so what's s of four + + align:start position:0% +2 which is 1 + 1 so what's s of four + + + align:start position:0% +2 which is 1 + 1 so what's s of four +three you might try a + + align:start position:0% +three you might try a + + + align:start position:0% +three you might try a +guess what would you + + align:start position:0% +guess what would you + + + align:start position:0% +guess what would you +guess yeah n minus one okay so we're + + align:start position:0% +guess yeah n minus one okay so we're + + + align:start position:0% +guess yeah n minus one okay so we're +going to + + align:start position:0% + + + + align:start position:0% + +guess s of n = n minus1 and that's not + + align:start position:0% +guess s of n = n minus1 and that's not + + + align:start position:0% +guess s of n = n minus1 and that's not +so bad actually it's pretty simple + + align:start position:0% +so bad actually it's pretty simple + + + align:start position:0% +so bad actually it's pretty simple +looking at that mess you'd never you + + align:start position:0% +looking at that mess you'd never you + + + align:start position:0% +looking at that mess you'd never you +know think of that right away but once + + align:start position:0% +know think of that right away but once + + + align:start position:0% +know think of that right away but once +you plug in some values that's not so + + align:start position:0% +you plug in some values that's not so + + + align:start position:0% +you plug in some values that's not so +bad all right let's verify + + align:start position:0% + + + + align:start position:0% + +it and we're going to verify by strong + + align:start position:0% + + + + align:start position:0% + +induction the induction hypothesis is + + align:start position:0% +induction the induction hypothesis is + + + align:start position:0% +induction the induction hypothesis is +our + + align:start position:0% + + + + align:start position:0% + +guess the the base case is + + align:start position:0% + + + + align:start position:0% + +easy because I've got s of + + align:start position:0% +easy because I've got s of + + + align:start position:0% +easy because I've got s of +one is zero and that equals 1 minus + + align:start position:0% +one is zero and that equals 1 minus + + + align:start position:0% +one is zero and that equals 1 minus +one so that's good so let's do the + + align:start position:0% +one so that's good so let's do the + + + align:start position:0% +one so that's good so let's do the +induction step + + align:start position:0% + + + + align:start position:0% + +all right so the induction + + align:start position:0% + + + + align:start position:0% + +step we're going to + + align:start position:0% + + + + align:start position:0% + +assume that P1 is true P2 is true all + + align:start position:0% +assume that P1 is true P2 is true all + + + align:start position:0% +assume that P1 is true P2 is true all +the way up to + + align:start position:0% +the way up to + + + align:start position:0% +the way up to +PN to prove PN + + + align:start position:0% +PN to prove PN + + + + align:start position:0% +PN to prove PN + +one is + + align:start position:0% +one is + + + align:start position:0% +one is +true for n bigger than equal to one and + + align:start position:0% +true for n bigger than equal to one and + + + align:start position:0% +true for n bigger than equal to one and +then we look at the N plus first + + align:start position:0% +then we look at the N plus first + + + align:start position:0% +then we look at the N plus first +term that equals s of floor n + 1 + + align:start position:0% + + + + align:start position:0% + +over2 plus s of ceiling n + 1 + + align:start position:0% +over2 plus s of ceiling n + 1 + + + align:start position:0% +over2 plus s of ceiling n + 1 +over2 plus + + align:start position:0% +over2 plus + + + align:start position:0% +over2 plus +one all right + + align:start position:0% +one all right + + + align:start position:0% +one all right +now I don't know what these are exactly + + align:start position:0% +now I don't know what these are exactly + + + align:start position:0% +now I don't know what these are exactly +depending on whether n is even or odd + + align:start position:0% +depending on whether n is even or odd + + + align:start position:0% +depending on whether n is even or odd +but I do well no I can plug first let me + + align:start position:0% +but I do well no I can plug first let me + + + align:start position:0% +but I do well no I can plug first let me +plug in using the induction + + align:start position:0% +plug in using the induction + + + align:start position:0% +plug in using the induction +hypothesis I know that this is n +1 / 2 + + align:start position:0% +hypothesis I know that this is n +1 / 2 + + + align:start position:0% +hypothesis I know that this is n +1 / 2 +-1 this is + + align:start position:0% +-1 this is + + + align:start position:0% +-1 this is +ceiling n + 1 / 2 minus1 and then I + + align:start position:0% +ceiling n + 1 / 2 minus1 and then I + + + align:start position:0% +ceiling n + 1 / 2 minus1 and then I +carry the plus one down that's by the + + align:start position:0% +carry the plus one down that's by the + + + align:start position:0% +carry the plus one down that's by the +induction + + align:start position:0% + + + + align:start position:0% + +hypothesis all right now I don't know + + align:start position:0% +hypothesis all right now I don't know + + + align:start position:0% +hypothesis all right now I don't know +exactly what either of these values is + + align:start position:0% +exactly what either of these values is + + + align:start position:0% +exactly what either of these values is +unless I know the par of n but I do know + + align:start position:0% +unless I know the par of n but I do know + + + align:start position:0% +unless I know the par of n but I do know +the sum of these two things the floor of + + align:start position:0% +the sum of these two things the floor of + + + align:start position:0% +the sum of these two things the floor of +something plus the ceiling of that + + align:start position:0% +something plus the ceiling of that + + + align:start position:0% +something plus the ceiling of that +something is twice the + + align:start position:0% +something is twice the + + + align:start position:0% +something is twice the +something all right so this this plus + + align:start position:0% +something all right so this this plus + + + align:start position:0% +something all right so this this plus +that equals n+ + + align:start position:0% +that equals n+ + + + align:start position:0% +that equals n+ +one -1 -1 + 1 is min + + align:start position:0% +one -1 -1 + 1 is min + + + align:start position:0% +one -1 -1 + 1 is min +-1 and so in fact we provve that s of n + + align:start position:0% +-1 and so in fact we provve that s of n + + + align:start position:0% +-1 and so in fact we provve that s of n ++ 1 equal n + + align:start position:0% ++ 1 equal n + + + align:start position:0% ++ 1 equal n ++1 minus + + align:start position:0% ++1 minus + + + align:start position:0% ++1 minus +one so we verified the induction + + align:start position:0% +one so we verified the induction + + + align:start position:0% +one so we verified the induction +hypothesis + + align:start position:0% + + + + align:start position:0% + +yeah um let's see I'm not sure so are + + align:start position:0% +yeah um let's see I'm not sure so are + + + align:start position:0% +yeah um let's see I'm not sure so are +you + + align:start position:0% +you + + + align:start position:0% +you +asking why I started SN plus one + + align:start position:0% + + + + align:start position:0% + +here uh um doesn't matter but uh the + + align:start position:0% +here uh um doesn't matter but uh the + + + align:start position:0% +here uh um doesn't matter but uh the +expression is s of whatever this is the + + align:start position:0% +expression is s of whatever this is the + + + align:start position:0% +expression is s of whatever this is the +induction ioth thesis would be S of + + align:start position:0% +induction ioth thesis would be S of + + + align:start position:0% +induction ioth thesis would be S of +whatever is inside there is what's + + align:start position:0% +whatever is inside there is what's + + + align:start position:0% +whatever is inside there is what's +inside there minus one and so the + + align:start position:0% +inside there minus one and so the + + + align:start position:0% +inside there minus one and so the +induction hypothesis says s of this is + + align:start position:0% +induction hypothesis says s of this is + + + align:start position:0% +induction hypothesis says s of this is +that minus + + align:start position:0% +that minus + + + align:start position:0% +that minus +one okay any other + + align:start position:0% + + + + align:start position:0% + +questions + + align:start position:0% +questions + + + align:start position:0% +questions +okay so let's write that on our table up + + align:start position:0% +okay so let's write that on our table up + + + align:start position:0% +okay so let's write that on our table up +here + + align:start position:0% + + + + align:start position:0% + +so this is SN equals s of Floor N + + align:start position:0% +so this is SN equals s of Floor N + + + align:start position:0% +so this is SN equals s of Floor N +/2 plus s of ceiling n + + align:start position:0% +/2 plus s of ceiling n + + + align:start position:0% +/2 plus s of ceiling n +/2 plus one and the answer + + align:start position:0% +/2 plus one and the answer + + + align:start position:0% +/2 plus one and the answer +is SN is Tilda what's a Tilda + + align:start position:0% + + + + align:start position:0% + +of n the answer is n minus one so it's + + align:start position:0% +of n the answer is n minus one so it's + + + align:start position:0% +of n the answer is n minus one so it's +till of n + + align:start position:0% +till of n + + + align:start position:0% +till of n +now this is the same expression as this + + align:start position:0% +now this is the same expression as this + + + align:start position:0% +now this is the same expression as this +if n's a power of two I'd have 2 SN / 2 + + align:start position:0% +if n's a power of two I'd have 2 SN / 2 + + + align:start position:0% +if n's a power of two I'd have 2 SN / 2 +plus one instead of n minus one and so + + align:start position:0% +plus one instead of n minus one and so + + + align:start position:0% +plus one instead of n minus one and so +I'm by going from n minus one to one I + + align:start position:0% +I'm by going from n minus one to one I + + + align:start position:0% +I'm by going from n minus one to one I +got rid of the log + + align:start position:0% +got rid of the log + + + align:start position:0% +got rid of the log +term all right but it's still you know + + align:start position:0% +term all right but it's still you know + + + align:start position:0% +term all right but it's still you know +not exponential and that's because I'm + + align:start position:0% +not exponential and that's because I'm + + + align:start position:0% +not exponential and that's because I'm +cutting down the insides here by a + + align:start position:0% +cutting down the insides here by a + + + align:start position:0% +cutting down the insides here by a +factor of two + + align:start position:0% +factor of two + + + align:start position:0% +factor of two +roughly okay + + align:start position:0% + + + + align:start position:0% + +all right + + align:start position:0% +all right + + + align:start position:0% +all right +so all the recurrences we've seen so far + + align:start position:0% +so all the recurrences we've seen so far + + + align:start position:0% +so all the recurrences we've seen so far +have been pretty simple uh if guess and + + align:start position:0% +have been pretty simple uh if guess and + + + align:start position:0% +have been pretty simple uh if guess and +verify doesn't work after seeing a few + + align:start position:0% +verify doesn't work after seeing a few + + + align:start position:0% +verify doesn't work after seeing a few +terms you can use plug and chug and you + + align:start position:0% +terms you can use plug and chug and you + + + align:start position:0% +terms you can use plug and chug and you +can figure it out uh the good news is + + align:start position:0% +can figure it out uh the good news is + + + align:start position:0% +can figure it out uh the good news is +that happens a lot in + + align:start position:0% +that happens a lot in + + + align:start position:0% +that happens a lot in +practice the bad news is sometimes it + + align:start position:0% +practice the bad news is sometimes it + + + align:start position:0% +practice the bad news is sometimes it +doesn't and you can get nasty + + align:start position:0% +doesn't and you can get nasty + + + align:start position:0% +doesn't and you can get nasty +recurrences so let me show you a uh a + + align:start position:0% +recurrences so let me show you a uh a + + + align:start position:0% +recurrences so let me show you a uh a +nasty + + align:start position:0% +nasty + + + align:start position:0% +nasty +one that actually was once uh uh asked + + align:start position:0% +one that actually was once uh uh asked + + + align:start position:0% +one that actually was once uh uh asked +in 6046 I think on a uh + + align:start position:0% + + + + align:start position:0% + +quiz with disastrous + + align:start position:0% + + + + align:start position:0% + +results all right + + align:start position:0% +results all right + + + align:start position:0% +results all right +so this one is T of + + align:start position:0% +so this one is T of + + + align:start position:0% +so this one is T of +x + + align:start position:0% +x + + + align:start position:0% +x +equals 2 T of X over 2 + + align:start position:0% +equals 2 T of X over 2 + + + align:start position:0% +equals 2 T of X over 2 +Plus 8 + + align:start position:0% +Plus 8 + + + align:start position:0% +Plus 8 +9th T of 3x over + + align:start position:0% +9th T of 3x over + + + align:start position:0% +9th T of 3x over +4 plus + + align:start position:0% +4 plus + + + align:start position:0% +4 plus +X2 for X bigger than equal to 1 and + + align:start position:0% +X2 for X bigger than equal to 1 and + + + align:start position:0% +X2 for X bigger than equal to 1 and +otherwise it's zero when X is less than + + align:start position:0% + + + + align:start position:0% + +one now this is nasty for a lot of + + align:start position:0% +one now this is nasty for a lot of + + + align:start position:0% +one now this is nasty for a lot of +reasons first it's not just to find on + + align:start position:0% +reasons first it's not just to find on + + + align:start position:0% +reasons first it's not just to find on +the integers we can make an integer + + align:start position:0% +the integers we can make an integer + + + align:start position:0% +the integers we can make an integer +verion by putting floors or ceilings + + align:start position:0% +verion by putting floors or ceilings + + + align:start position:0% +verion by putting floors or ceilings +here but the way you set it up now it's + + align:start position:0% +here but the way you set it up now it's + + + align:start position:0% +here but the way you set it up now it's +defined on real + + align:start position:0% +defined on real + + + align:start position:0% +defined on real +numbers + + align:start position:0% +numbers + + + align:start position:0% +numbers +uh you can in theory solve it with plug + + align:start position:0% +uh you can in theory solve it with plug + + + align:start position:0% +uh you can in theory solve it with plug +and chug the nasty part is you got a + + align:start position:0% +and chug the nasty part is you got a + + + align:start position:0% +and chug the nasty part is you got a +bunch of things going down by powers of + + align:start position:0% +bunch of things going down by powers of + + + align:start position:0% +bunch of things going down by powers of +Two and a bunch of things going down by + + align:start position:0% +Two and a bunch of things going down by + + + align:start position:0% +Two and a bunch of things going down by +three qus here and so you have to keep + + align:start position:0% +three qus here and so you have to keep + + + align:start position:0% +three qus here and so you have to keep +track of all the terms that are + + align:start position:0% +track of all the terms that are + + + align:start position:0% +track of all the terms that are +decreasing and that's a a nightmare + + align:start position:0% +decreasing and that's a a nightmare + + + align:start position:0% +decreasing and that's a a nightmare +plug-and chug because it's not just one + + align:start position:0% +plug-and chug because it's not just one + + + align:start position:0% +plug-and chug because it's not just one +thing that's unfolding it's two things + + align:start position:0% +thing that's unfolding it's two things + + + align:start position:0% +thing that's unfolding it's two things +things that are + + align:start position:0% +things that are + + + align:start position:0% +things that are +unfolding uh so very + + align:start position:0% +unfolding uh so very + + + align:start position:0% +unfolding uh so very +painful + + align:start position:0% +painful + + + align:start position:0% +painful +now it used to be that was the state of + + align:start position:0% +now it used to be that was the state of + + + align:start position:0% +now it used to be that was the state of +Life 20 years ago I think we started + + align:start position:0% +Life 20 years ago I think we started + + + align:start position:0% +Life 20 years ago I think we started +teaching this course sometime around + + align:start position:0% +teaching this course sometime around + + + align:start position:0% +teaching this course sometime around +then there just was no nothing else to + + align:start position:0% +then there just was no nothing else to + + + align:start position:0% +then there just was no nothing else to +say other then life's tough and + + align:start position:0% +say other then life's tough and + + + align:start position:0% +say other then life's tough and +sometimes you got to do these things and + + align:start position:0% +sometimes you got to do these things and + + + align:start position:0% +sometimes you got to do these things and +it's a it's a pain uh just had to make + + align:start position:0% +it's a it's a pain uh just had to make + + + align:start position:0% +it's a it's a pain uh just had to make +the best of it and then in the mid90s + + align:start position:0% +the best of it and then in the mid90s + + + align:start position:0% +the best of it and then in the mid90s +one day two students at the American + + align:start position:0% +one day two students at the American + + + align:start position:0% +one day two students at the American +University in Beirut came by my office + + align:start position:0% +University in Beirut came by my office + + + align:start position:0% +University in Beirut came by my office +uh they were named Acra and + + align:start position:0% +uh they were named Acra and + + + align:start position:0% +uh they were named Acra and +botsi uh and they'd actually come to + + align:start position:0% +botsi uh and they'd actually come to + + + align:start position:0% +botsi uh and they'd actually come to +Boston to escape the daily bombings this + + align:start position:0% +Boston to escape the daily bombings this + + + align:start position:0% +Boston to escape the daily bombings this +one was all heck was break breaking + + align:start position:0% +one was all heck was break breaking + + + align:start position:0% +one was all heck was break breaking +loose in Bay rout and it was a mess and + + align:start position:0% +loose in Bay rout and it was a mess and + + + align:start position:0% +loose in Bay rout and it was a mess and +they come into my office and they claim + + align:start position:0% +they come into my office and they claim + + + align:start position:0% +they come into my office and they claim +to have a simple formula for solving any + + align:start position:0% +to have a simple formula for solving any + + + align:start position:0% +to have a simple formula for solving any +recurrence like this in fact you could + + align:start position:0% +recurrence like this in fact you could + + + align:start position:0% +recurrence like this in fact you could +even add you know a a 5 T of X over 7 + + align:start position:0% +even add you know a a 5 T of X over 7 + + + align:start position:0% +even add you know a a 5 T of X over 7 +they said no problem their simple + + align:start position:0% +they said no problem their simple + + + align:start position:0% +they said no problem their simple +formula just will always + + align:start position:0% +formula just will always + + + align:start position:0% +formula just will always +work all right and the general form that + + align:start position:0% +work all right and the general form that + + + align:start position:0% +work all right and the general form that +they claim to solve was the + + align:start position:0% +they claim to solve was the + + + align:start position:0% +they claim to solve was the +following it's the general class of + + align:start position:0% +following it's the general class of + + + align:start position:0% +following it's the general class of +divide and conquer recurrences so any + + align:start position:0% +divide and conquer recurrences so any + + + align:start position:0% +divide and conquer recurrences so any +recurrence you get from an algorithm + + align:start position:0% +recurrence you get from an algorithm + + + align:start position:0% +recurrence you get from an algorithm +where you break it into smaller pieces + + align:start position:0% +where you break it into smaller pieces + + + align:start position:0% +where you break it into smaller pieces +by a constant Factor they claim to solve + + align:start position:0% +by a constant Factor they claim to solve + + + align:start position:0% +by a constant Factor they claim to solve +so let me Define this class it's a + + align:start position:0% +so let me Define this class it's a + + + align:start position:0% +so let me Define this class it's a +little painful + + align:start position:0% + + + + align:start position:0% + +so a defied and Conquer + + align:start position:0% + + + + align:start position:0% + +recurrence has the + + align:start position:0% + + + + align:start position:0% + +form you know there's a simple version + + align:start position:0% +form you know there's a simple version + + + align:start position:0% +form you know there's a simple version +and the hard version the simple version + + align:start position:0% +and the hard version the simple version + + + align:start position:0% +and the hard version the simple version +is it looks like that all right you got + + align:start position:0% +is it looks like that all right you got + + + align:start position:0% +is it looks like that all right you got +a bunch of terms inside each term you + + align:start position:0% +a bunch of terms inside each term you + + + align:start position:0% +a bunch of terms inside each term you +cut it down by a constant factor and + + align:start position:0% +cut it down by a constant factor and + + + align:start position:0% +cut it down by a constant factor and +then you add something at the end that's + + align:start position:0% +then you add something at the end that's + + + align:start position:0% +then you add something at the end that's +the simple version of what a divide and + + align:start position:0% +the simple version of what a divide and + + + align:start position:0% +the simple version of what a divide and +conquer recurrence is is and you can + + align:start position:0% +conquer recurrence is is and you can + + + align:start position:0% +conquer recurrence is is and you can +throw in floors and ceilings and other + + align:start position:0% +throw in floors and ceilings and other + + + align:start position:0% +throw in floors and ceilings and other +junk tube all right now I'm going to + + align:start position:0% +junk tube all right now I'm going to + + + align:start position:0% +junk tube all right now I'm going to +give you the formal + + align:start position:0% + + + + align:start position:0% + +version so it has the form T of x equals + + align:start position:0% +version so it has the form T of x equals + + + align:start position:0% +version so it has the form T of x equals +some constant + + align:start position:0% +some constant + + + align:start position:0% +some constant +A1 time T of a constant less than one B1 + + align:start position:0% +A1 time T of a constant less than one B1 + + + align:start position:0% +A1 time T of a constant less than one B1 +ofx plus some slop you're allowed to + + align:start position:0% +ofx plus some slop you're allowed to + + + align:start position:0% +ofx plus some slop you're allowed to +have like floors and ceilings and who + + align:start position:0% +have like floors and ceilings and who + + + align:start position:0% +have like floors and ceilings and who +knows what else and then you get more of + + align:start position:0% +knows what else and then you get more of + + + align:start position:0% +knows what else and then you get more of +these you get + + align:start position:0% +these you get + + + align:start position:0% +these you get +A2 T of + + align:start position:0% +A2 T of + + + align:start position:0% +A2 T of +b2x plus Epsilon + + align:start position:0% +b2x plus Epsilon + + + align:start position:0% +b2x plus Epsilon +2X and so forth and you can have any + + align:start position:0% +2X and so forth and you can have any + + + align:start position:0% +2X and so forth and you can have any +number of these you want up to a + + align:start position:0% +number of these you want up to a + + + align:start position:0% +number of these you want up to a +constant so maybe there's a subk t b sub + + align:start position:0% +constant so maybe there's a subk t b sub + + + align:start position:0% +constant so maybe there's a subk t b sub +KX plus Epsilon + + align:start position:0% + + + + align:start position:0% + +KX plus some function of X sitting out + + align:start position:0% +KX plus some function of X sitting out + + + align:start position:0% +KX plus some function of X sitting out +here like the X + + align:start position:0% +here like the X + + + align:start position:0% +here like the X +squ and this happens for X bigger than + + align:start position:0% +squ and this happens for X bigger than + + + align:start position:0% +squ and this happens for X bigger than +some fixed value some constant + + align:start position:0% +some fixed value some constant + + + align:start position:0% +some fixed value some constant +now the constraints + + align:start position:0% +now the constraints + + + align:start position:0% +now the constraints +are well the AI are positive + + align:start position:0% + + + + align:start position:0% + +constants the bi are positive and less + + align:start position:0% +constants the bi are positive and less + + + align:start position:0% +constants the bi are positive and less +than + + align:start position:0% +than + + + align:start position:0% +than +one you got to cut it down by a constant + + align:start position:0% +one you got to cut it down by a constant + + + align:start position:0% +one you got to cut it down by a constant +factor to be the divide and conquer + + align:start position:0% +factor to be the divide and conquer + + + align:start position:0% +factor to be the divide and conquer +recurrence that's + + align:start position:0% +recurrence that's + + + align:start position:0% +recurrence that's +critical uh K is fixed it's + + align:start position:0% + + + + align:start position:0% + +constant and these functions can't be + + align:start position:0% +constant and these functions can't be + + + align:start position:0% +constant and these functions can't be +too big uh they can't be bigger than o + + align:start position:0% +too big uh they can't be bigger than o + + + align:start position:0% +too big uh they can't be bigger than o +of X over log s of X almost as big as X + + align:start position:0% +of X over log s of X almost as big as X + + + align:start position:0% +of X over log s of X almost as big as X +but you can't let them be too big or + + align:start position:0% +but you can't let them be too big or + + + align:start position:0% +but you can't let them be too big or +you'll not be cutting things down by a + + align:start position:0% +you'll not be cutting things down by a + + + align:start position:0% +you'll not be cutting things down by a +constant + + align:start position:0% +constant + + + align:start position:0% +constant +factor and you don't get too hung up + + align:start position:0% +factor and you don't get too hung up + + + align:start position:0% +factor and you don't get too hung up +over this + + align:start position:0% +over this + + + align:start position:0% +over this +because you know you don't get too deep + + align:start position:0% +because you know you don't get too deep + + + align:start position:0% +because you know you don't get too deep +in the details but this is at most o of + + align:start position:0% +in the details but this is at most o of + + + align:start position:0% +in the details but this is at most o of +X over log + + align:start position:0% + + + + align:start position:0% + +X and find finally the G thing it's got + + align:start position:0% +X and find finally the G thing it's got + + + align:start position:0% +X and find finally the G thing it's got +to be polom it can't be an exponent you + + align:start position:0% +to be polom it can't be an exponent you + + + align:start position:0% +to be polom it can't be an exponent you +can't put 2 to the X here and the formal + + align:start position:0% +can't put 2 to the X here and the formal + + + align:start position:0% +can't put 2 to the X here and the formal +way that's expressed is the derivative + + align:start position:0% +way that's expressed is the derivative + + + align:start position:0% +way that's expressed is the derivative +of + + align:start position:0% + + + + align:start position:0% + +G of X is less than x to the C for some + + align:start position:0% +G of X is less than x to the C for some + + + align:start position:0% +G of X is less than x to the C for some +constant + + align:start position:0% + + + + align:start position:0% + +C that's it so this is a mouthful but + + align:start position:0% +C that's it so this is a mouthful but + + + align:start position:0% +C that's it so this is a mouthful but +like I said before anything that looks + + align:start position:0% +like I said before anything that looks + + + align:start position:0% +like I said before anything that looks +like + + align:start position:0% +like + + + align:start position:0% +like +that okay basically as long as you don't + + align:start position:0% +that okay basically as long as you don't + + + align:start position:0% +that okay basically as long as you don't +throw in exponentials or do something + + align:start position:0% +throw in exponentials or do something + + + align:start position:0% +throw in exponentials or do something +too wild to + + align:start position:0% +too wild to + + + align:start position:0% +too wild to +it it works so let's see which of our + + align:start position:0% +it it works so let's see which of our + + + align:start position:0% +it it works so let's see which of our +guys over here are divide and conquer + + align:start position:0% + + + + align:start position:0% + +recurrences how about this one towers of + + align:start position:0% +recurrences how about this one towers of + + + align:start position:0% +recurrences how about this one towers of +anoi is that a divide and conquer + + align:start position:0% + + + + align:start position:0% + +recurrence some yes some + + align:start position:0% +recurrence some yes some + + + align:start position:0% +recurrence some yes some +no all right who thinks no can tell me + + align:start position:0% +no all right who thinks no can tell me + + + align:start position:0% +no all right who thinks no can tell me +why it's not why isn't that + + align:start position:0% +why it's not why isn't that + + + align:start position:0% +why it's not why isn't that +by any factor that is less than that's + + align:start position:0% +by any factor that is less than that's + + + align:start position:0% +by any factor that is less than that's +right the recurrence problem is n minus + + align:start position:0% +right the recurrence problem is n minus + + + align:start position:0% +right the recurrence problem is n minus +one and we got to make + + align:start position:0% +one and we got to make + + + align:start position:0% +one and we got to make +it down by a constant Factor here the B1 + + align:start position:0% +it down by a constant Factor here the B1 + + + align:start position:0% +it down by a constant Factor here the B1 +is less than one it can't be equal to + + align:start position:0% +is less than one it can't be equal to + + + align:start position:0% +is less than one it can't be equal to +one and this is not big enough to make + + align:start position:0% +one and this is not big enough to make + + + align:start position:0% +one and this is not big enough to make +up for you know the X over two term or + + align:start position:0% +up for you know the X over two term or + + + align:start position:0% +up for you know the X over two term or +something we're missing so whenever you + + align:start position:0% +something we're missing so whenever you + + + align:start position:0% +something we're missing so whenever you +have an N minus one or an N minus two + + align:start position:0% +have an N minus one or an N minus two + + + align:start position:0% +have an N minus one or an N minus two +that is not divide and + + align:start position:0% +that is not divide and + + + align:start position:0% +that is not divide and +conquer uh we'll discuss those next time + + align:start position:0% +conquer uh we'll discuss those next time + + + align:start position:0% +conquer uh we'll discuss those next time +on Thursday how to solve those so that's + + align:start position:0% +on Thursday how to solve those so that's + + + align:start position:0% +on Thursday how to solve those so that's +not divide and + + align:start position:0% +not divide and + + + align:start position:0% +not divide and +conquer what about this one is that + + align:start position:0% +conquer what about this one is that + + + align:start position:0% +conquer what about this one is that +divide and conquer + + align:start position:0% + + + + align:start position:0% + +here yes you've got two problems of half + + align:start position:0% +here yes you've got two problems of half + + + align:start position:0% +here yes you've got two problems of half +the size and you're adding a linear + + align:start position:0% +the size and you're adding a linear + + + align:start position:0% +the size and you're adding a linear +function it's not exponential it's + + align:start position:0% +function it's not exponential it's + + + align:start position:0% +function it's not exponential it's +polinomial that is divide and + + align:start position:0% +polinomial that is divide and + + + align:start position:0% +polinomial that is divide and +conquer what about this this nasty guy + + align:start position:0% +conquer what about this this nasty guy + + + align:start position:0% +conquer what about this this nasty guy +is that divide and + + align:start position:0% + + + + align:start position:0% + +conquer yeah you've got basically n/2 + + align:start position:0% +conquer yeah you've got basically n/2 + + + align:start position:0% +conquer yeah you've got basically n/2 +here two n/2 terms now this is where + + align:start position:0% +here two n/2 terms now this is where + + + align:start position:0% +here two n/2 terms now this is where +that Epsilon thing comes in handy + + align:start position:0% +that Epsilon thing comes in handy + + + align:start position:0% +that Epsilon thing comes in handy +because Epsilon one of n in this case is + + align:start position:0% +because Epsilon one of n in this case is + + + align:start position:0% +because Epsilon one of n in this case is +FL n / + + align:start position:0% +FL n / + + + align:start position:0% +FL n / +2 minus n over two and that's at most + + align:start position:0% + + + + align:start position:0% + +one all right so we're adding maybe + + align:start position:0% +one all right so we're adding maybe + + + align:start position:0% +one all right so we're adding maybe +we're adding a half here something like + + align:start position:0% +we're adding a half here something like + + + align:start position:0% +we're adding a half here something like +that and we're allowed to add anything + + align:start position:0% +that and we're allowed to add anything + + + align:start position:0% +that and we're allowed to add anything +up to n over log squ of n to fit + + align:start position:0% +up to n over log squ of n to fit + + + align:start position:0% +up to n over log squ of n to fit +all right so you can you can mess around + + align:start position:0% +all right so you can you can mess around + + + align:start position:0% +all right so you can you can mess around +with the low order terms in here and + + align:start position:0% +with the low order terms in here and + + + align:start position:0% +with the low order terms in here and +adding one is fine as well all right so + + align:start position:0% +adding one is fine as well all right so + + + align:start position:0% +adding one is fine as well all right so +that + + align:start position:0% +that + + + align:start position:0% +that +qualifies what about let we should check + + align:start position:0% +qualifies what about let we should check + + + align:start position:0% +qualifies what about let we should check +that this thing + + align:start position:0% +that this thing + + + align:start position:0% +that this thing +qualifies let's check + + align:start position:0% + + + + align:start position:0% + +that well yeah I + + align:start position:0% +that well yeah I + + + align:start position:0% +that well yeah I +got two constant + + align:start position:0% +got two constant + + + align:start position:0% +got two constant +A1 T of half X that's okay 8 9th T of + + align:start position:0% +A1 T of half X that's okay 8 9th T of + + + align:start position:0% +A1 T of half X that's okay 8 9th T of +3/4 x that's okay my G function is a + + align:start position:0% +3/4 x that's okay my G function is a + + + align:start position:0% +3/4 x that's okay my G function is a +polinomial the derivative is 2x that's + + align:start position:0% +polinomial the derivative is 2x that's + + + align:start position:0% +polinomial the derivative is 2x that's +less than x to a power or of x to a + + align:start position:0% +less than x to a power or of x to a + + + align:start position:0% +less than x to a power or of x to a +power so this + + align:start position:0% + + + + align:start position:0% + +fits okay any questions about the + + align:start position:0% +fits okay any questions about the + + + align:start position:0% +fits okay any questions about the +definition of a divide and conquer + + align:start position:0% + + + + align:start position:0% + +recurrence okay and you can see why sort + + align:start position:0% +recurrence okay and you can see why sort + + + align:start position:0% +recurrence okay and you can see why sort +of they come up because whenever you're + + align:start position:0% +of they come up because whenever you're + + + align:start position:0% +of they come up because whenever you're +solving a problem with recursive pieces + + align:start position:0% +solving a problem with recursive pieces + + + align:start position:0% +solving a problem with recursive pieces +that are a constant Factor smaller + + align:start position:0% +that are a constant Factor smaller + + + align:start position:0% +that are a constant Factor smaller +you're going to have something that that + + align:start position:0% +you're going to have something that that + + + align:start position:0% +you're going to have something that that +looks like + + align:start position:0% +looks like + + + align:start position:0% +looks like +that okay so getting back to Acra and + + align:start position:0% +that okay so getting back to Acra and + + + align:start position:0% +that okay so getting back to Acra and +batsi you know they show up in my office + + align:start position:0% +batsi you know they show up in my office + + + align:start position:0% +batsi you know they show up in my office +they claim to have solved anything like + + align:start position:0% +they claim to have solved anything like + + + align:start position:0% +they claim to have solved anything like +this now needless to say I'm a little + + align:start position:0% +this now needless to say I'm a little + + + align:start position:0% +this now needless to say I'm a little +skeptical you know I got to tell you + + align:start position:0% +skeptical you know I got to tell you + + + align:start position:0% +skeptical you know I got to tell you +you're a professor at MIT especially in + + align:start position:0% +you're a professor at MIT especially in + + + align:start position:0% +you're a professor at MIT especially in +mathematics and uh people are always + + align:start position:0% +mathematics and uh people are always + + + align:start position:0% +mathematics and uh people are always +coming by with proofs of you know the + + align:start position:0% +coming by with proofs of you know the + + + align:start position:0% +coming by with proofs of you know the +remon hypothesis P equals NP P doesn't + + align:start position:0% +remon hypothesis P equals NP P doesn't + + + align:start position:0% +remon hypothesis P equals NP P doesn't +equal NP + + align:start position:0% +equal NP + + + align:start position:0% +equal NP +you know and this was a classic problem + + align:start position:0% +you know and this was a classic problem + + + align:start position:0% +you know and this was a classic problem +you know hundreds of researchers had + + align:start position:0% +you know hundreds of researchers had + + + align:start position:0% +you know hundreds of researchers had +studied recurrences for decades and not + + align:start position:0% +studied recurrences for decades and not + + + align:start position:0% +studied recurrences for decades and not +only it wasn't even believed that there + + align:start position:0% +only it wasn't even believed that there + + + align:start position:0% +only it wasn't even believed that there +was possibly a solution it's not like + + align:start position:0% +was possibly a solution it's not like + + + align:start position:0% +was possibly a solution it's not like +it's one of these open questions where + + align:start position:0% +it's one of these open questions where + + + align:start position:0% +it's one of these open questions where +we all believe P doesn't equal NP in a + + align:start position:0% +we all believe P doesn't equal NP in a + + + align:start position:0% +we all believe P doesn't equal NP in a +Sy matter approving it people didn't + + align:start position:0% +Sy matter approving it people didn't + + + align:start position:0% +Sy matter approving it people didn't +think a solution existed that would be + + align:start position:0% +think a solution existed that would be + + + align:start position:0% +think a solution existed that would be +clean I mean look at just the + + align:start position:0% +clean I mean look at just the + + + align:start position:0% +clean I mean look at just the +definitions of mess how could there + + align:start position:0% +definitions of mess how could there + + + align:start position:0% +definitions of mess how could there +possibly be a clean solution to + + align:start position:0% +possibly be a clean solution to + + + align:start position:0% +possibly be a clean solution to +that you know so it's sort of like the + + align:start position:0% +that you know so it's sort of like the + + + align:start position:0% +that you know so it's sort of like the +Holy Grail you know it doesn't exist but + + align:start position:0% +Holy Grail you know it doesn't exist but + + + align:start position:0% +Holy Grail you know it doesn't exist but +it's fun to think about but a fantasy + + align:start position:0% +it's fun to think about but a fantasy + + + align:start position:0% +it's fun to think about but a fantasy +maybe there's a solution and you could + + align:start position:0% +maybe there's a solution and you could + + + align:start position:0% +maybe there's a solution and you could +find + + align:start position:0% +find + + + align:start position:0% +find +it um and much less these aren't + + align:start position:0% +it um and much less these aren't + + + align:start position:0% +it um and much less these aren't +reputable researchers in my office these + + align:start position:0% +reputable researchers in my office these + + + align:start position:0% +reputable researchers in my office these +are two students from Beirut named ACA + + align:start position:0% +are two students from Beirut named ACA + + + align:start position:0% +are two students from Beirut named ACA +and batsi claiming that they've figured + + align:start position:0% +and batsi claiming that they've figured + + + align:start position:0% +and batsi claiming that they've figured +out this thing that all these professors + + align:start position:0% +out this thing that all these professors + + + align:start position:0% +out this thing that all these professors +been teaching this stuff in 6046 for + + align:start position:0% +been teaching this stuff in 6046 for + + + align:start position:0% +been teaching this stuff in 6046 for +years said doesn't you got to do plugin + + align:start position:0% +years said doesn't you got to do plugin + + + align:start position:0% +years said doesn't you got to do plugin +shot um anyway you know they've been + + align:start position:0% +shot um anyway you know they've been + + + align:start position:0% +shot um anyway you know they've been +kicked out of everybody else's office I + + align:start position:0% +kicked out of everybody else's office I + + + align:start position:0% +kicked out of everybody else's office I +said okay let's let's do it show me the + + align:start position:0% +said okay let's let's do it show me the + + + align:start position:0% +said okay let's let's do it show me the +solution and they did and I go holy cow + + align:start position:0% +solution and they did and I go holy cow + + + align:start position:0% +solution and they did and I go holy cow +it's right you know it looks good now + + align:start position:0% +it's right you know it looks good now + + + align:start position:0% +it's right you know it looks good now +they had a few details wrong but oh my + + align:start position:0% +they had a few details wrong but oh my + + + align:start position:0% +they had a few details wrong but oh my +goodness the answer was correct and it's + + align:start position:0% +goodness the answer was correct and it's + + + align:start position:0% +goodness the answer was correct and it's +amazingly + + align:start position:0% +amazingly + + + align:start position:0% +amazingly +simple all right so now we teach + + align:start position:0% +simple all right so now we teach + + + align:start position:0% +simple all right so now we teach +it and uh fact you can write the + + align:start position:0% +it and uh fact you can write the + + + align:start position:0% +it and uh fact you can write the +solution down easier than can you can + + align:start position:0% +solution down easier than can you can + + + align:start position:0% +solution down easier than can you can +write the definition of divide and + + align:start position:0% +write the definition of divide and + + + align:start position:0% +write the definition of divide and +conquer + + align:start position:0% +conquer + + + align:start position:0% +conquer +recurrence really remarkable + + align:start position:0% + + + + align:start position:0% + +right so the + + align:start position:0% +right so the + + + align:start position:0% +right so the +theorem by AAR and + + align:start position:0% + + + + align:start position:0% + +bobsy in + + align:start position:0% + + + + align:start position:0% + +96 set p real number so + + align:start position:0% +96 set p real number so + + + align:start position:0% +96 set p real number so +that the sum IAL 1 to + + align:start position:0% +that the sum IAL 1 to + + + align:start position:0% +that the sum IAL 1 to +K of AI I * b i to the P equal 1 so the + + align:start position:0% +K of AI I * b i to the P equal 1 so the + + + align:start position:0% +K of AI I * b i to the P equal 1 so the +AI are these things here the bis are the + + align:start position:0% +AI are these things here the bis are the + + + align:start position:0% +AI are these things here the bis are the +fractions + + align:start position:0% +fractions + + + align:start position:0% +fractions +here all right find a p such that + + align:start position:0% +here all right find a p such that + + + align:start position:0% +here all right find a p such that +this sum is one all right then the + + align:start position:0% +this sum is one all right then the + + + align:start position:0% +this sum is one all right then the +answer is + + align:start position:0% +answer is + + + align:start position:0% +answer is +this then T of + + align:start position:0% +this then T of + + + align:start position:0% +this then T of +x equals Theta we're going to use our + + align:start position:0% +x equals Theta we're going to use our + + + align:start position:0% +x equals Theta we're going to use our +ASM totic notation X the P plus x to the + + align:start position:0% +ASM totic notation X the P plus x to the + + + align:start position:0% +ASM totic notation X the P plus x to the +P time the integral from 1 to x g of u g + + align:start position:0% +P time the integral from 1 to x g of u g + + + align:start position:0% +P time the integral from 1 to x g of u g +is that polinomial thing the thing at + + align:start position:0% +is that polinomial thing the thing at + + + align:start position:0% +is that polinomial thing the thing at +the end over U to the P minus one + + align:start position:0% + + + + align:start position:0% + +du that's + + align:start position:0% +du that's + + + align:start position:0% +du that's +it all right this is really great news + + align:start position:0% +it all right this is really great news + + + align:start position:0% +it all right this is really great news +for you guys especially if you go on + + align:start position:0% +for you guys especially if you go on + + + align:start position:0% +for you guys especially if you go on +into algorithms because you don't have + + align:start position:0% +into algorithms because you don't have + + + align:start position:0% +into algorithms because you don't have +to deal with plug and chug on nasty + + align:start position:0% +to deal with plug and chug on nasty + + + align:start position:0% +to deal with plug and chug on nasty +things you just solve the the answer + + align:start position:0% +things you just solve the the answer + + + align:start position:0% +things you just solve the the answer +okay now the proof is by guess and + + align:start position:0% +okay now the proof is by guess and + + + align:start position:0% +okay now the proof is by guess and +verify and they made a really good + + align:start position:0% +verify and they made a really good + + + align:start position:0% +verify and they made a really good +guess right you know you wouldn't think + + align:start position:0% +guess right you know you wouldn't think + + + align:start position:0% +guess right you know you wouldn't think +looking at that oh I'm G to guess this + + align:start position:0% +looking at that oh I'm G to guess this + + + align:start position:0% +looking at that oh I'm G to guess this +you know probably not you know and + + align:start position:0% +you know probably not you know and + + + align:start position:0% +you know probably not you know and +there's no real numbers to try to guess + + align:start position:0% +there's no real numbers to try to guess + + + align:start position:0% +there's no real numbers to try to guess +this it's ASM totic + + align:start position:0% +this it's ASM totic + + + align:start position:0% +this it's ASM totic +notation um but it works when you you + + align:start position:0% +notation um but it works when you you + + + align:start position:0% +notation um but it works when you you +can verify it by induction it's a little + + align:start position:0% +can verify it by induction it's a little + + + align:start position:0% +can verify it by induction it's a little +painful to verify by induction but you + + align:start position:0% +painful to verify by induction but you + + + align:start position:0% +painful to verify by induction but you +can do it we won't do it in class I did + + align:start position:0% +can do it we won't do it in class I did + + + align:start position:0% +can do it we won't do it in class I did +try one year and it was a disaster so we + + align:start position:0% +try one year and it was a disaster so we + + + align:start position:0% +try one year and it was a disaster so we +don't do it in class anymore uh but + + align:start position:0% +don't do it in class anymore uh but + + + align:start position:0% +don't do it in class anymore uh but +let's see some examples of how to apply + + align:start position:0% +let's see some examples of how to apply + + + align:start position:0% +let's see some examples of how to apply +this all right so let's start with a + + align:start position:0% +this all right so let's start with a + + + align:start position:0% +this all right so let's start with a +merge + + align:start position:0% +merge + + + align:start position:0% +merge +sort which is the second one here let's + + align:start position:0% +sort which is the second one here let's + + + align:start position:0% +sort which is the second one here let's +do + + align:start position:0% + + + + align:start position:0% + +that all right so we got an example here + + align:start position:0% +that all right so we got an example here + + + align:start position:0% +that all right so we got an example here +T ofx + + align:start position:0% +T ofx + + + align:start position:0% +T ofx += 2 T ofx / + + align:start position:0% += 2 T ofx / + + + align:start position:0% += 2 T ofx / +2 plus n minus one or xus one X now and + + align:start position:0% +2 plus n minus one or xus one X now and + + + align:start position:0% +2 plus n minus one or xus one X now and +I'm not even going to worry about powers + + align:start position:0% +I'm not even going to worry about powers + + + align:start position:0% +I'm not even going to worry about powers +of two anymore I don't I don't care it's + + align:start position:0% +of two anymore I don't I don't care it's + + + align:start position:0% +of two anymore I don't I don't care it's +going to be + + align:start position:0% +going to be + + + align:start position:0% +going to be +fine all right what is p in this case + + align:start position:0% +fine all right what is p in this case + + + align:start position:0% +fine all right what is p in this case +I've only got one term I don't even need + + align:start position:0% +I've only got one term I don't even need + + + align:start position:0% +I've only got one term I don't even need +a sum from that definition over there + + align:start position:0% +a sum from that definition over there + + + align:start position:0% +a sum from that definition over there +what's the value of + + align:start position:0% +what's the value of + + + align:start position:0% +what's the value of +P for this guy + + align:start position:0% +P for this guy + + + align:start position:0% +P for this guy +so I've got A1 is + + align:start position:0% +so I've got A1 is + + + align:start position:0% +so I've got A1 is +two B1 is a half just one + + align:start position:0% + + + + align:start position:0% + +term what's the value of P such that 2 * + + align:start position:0% +term what's the value of P such that 2 * + + + align:start position:0% +term what's the value of P such that 2 * +a half to the P equals + + align:start position:0% +a half to the P equals + + + align:start position:0% +a half to the P equals +1 one doesn't get much + + align:start position:0% +1 one doesn't get much + + + align:start position:0% +1 one doesn't get much +simpler all right so 2 * a half to the P + + align:start position:0% +simpler all right so 2 * a half to the P + + + align:start position:0% +simpler all right so 2 * a half to the P +equal 1 implies p is + + align:start position:0% +equal 1 implies p is + + + align:start position:0% +equal 1 implies p is +1 all right now I just plug into the + + align:start position:0% +1 all right now I just plug into the + + + align:start position:0% +1 all right now I just plug into the +integral over there + + align:start position:0% +integral over there + + + align:start position:0% +integral over there +all right let's do + + align:start position:0% + + + + align:start position:0% + +that so T of + + align:start position:0% +that so T of + + + align:start position:0% +that so T of +x equals + + align:start position:0% +x equals + + + align:start position:0% +x equals +Theta well X the p is x 1 plus just take + + align:start position:0% +Theta well X the p is x 1 plus just take + + + align:start position:0% +Theta well X the p is x 1 plus just take +off the one plus x * the integral 1 tox + + align:start position:0% +off the one plus x * the integral 1 tox + + + align:start position:0% +off the one plus x * the integral 1 tox +what's the G + + align:start position:0% +what's the G + + + align:start position:0% +what's the G +function what's G of X in this + + align:start position:0% + + + + align:start position:0% + +case x + + align:start position:0% +case x + + + align:start position:0% +case x +-1 so I take the integral of G of U is + + align:start position:0% +-1 so I take the integral of G of U is + + + align:start position:0% +-1 so I take the integral of G of U is +just uus one + + align:start position:0% +just uus one + + + align:start position:0% +just uus one +over U to the p + + + align:start position:0% + + + + align:start position:0% + +1 P minus + + align:start position:0% +1 P minus + + + align:start position:0% +1 P minus +one uh did I write the formula right is + + align:start position:0% +one uh did I write the formula right is + + + align:start position:0% +one uh did I write the formula right is +it plus one or minus one + + align:start position:0% +it plus one or minus one + + + align:start position:0% +it plus one or minus one +here did I get it p+ one sorry didn't + + align:start position:0% +here did I get it p+ one sorry didn't + + + align:start position:0% +here did I get it p+ one sorry didn't +write that right p + one over + + align:start position:0% + + + + align:start position:0% + +here all right so U to the p+ one is + + align:start position:0% +here all right so U to the p+ one is + + + align:start position:0% +here all right so U to the p+ one is +u^2 + + align:start position:0% + + + + align:start position:0% + +Du all right this + + align:start position:0% +Du all right this + + + align:start position:0% +Du all right this +is Theta of x + x + + align:start position:0% +is Theta of x + x + + + align:start position:0% +is Theta of x + x +integral 1 / U u - 1 / u^ + + align:start position:0% + + + + align:start position:0% + +2 the integral of + + align:start position:0% + + + + align:start position:0% + +oops the integral of one over U is the + + align:start position:0% +oops the integral of one over U is the + + + align:start position:0% +oops the integral of one over U is the +log of + + align:start position:0% +log of + + + align:start position:0% +log of +U the integral of 1 over U2 is one over + + align:start position:0% +U the integral of 1 over U2 is one over + + + align:start position:0% +U the integral of 1 over U2 is one over +U but I changed the sign + + align:start position:0% +U but I changed the sign + + + align:start position:0% +U but I changed the sign +there one to X + + align:start position:0% + + + + align:start position:0% + +all right so I get Theta of x + x time + + align:start position:0% +all right so I get Theta of x + x time + + + align:start position:0% +all right so I get Theta of x + x time +log of + + align:start position:0% +log of + + + align:start position:0% +log of +x + 1 + + align:start position:0% +x + 1 + + + align:start position:0% +x + 1 +/x minus log of zero that's log of one + + align:start position:0% +/x minus log of zero that's log of one + + + align:start position:0% +/x minus log of zero that's log of one +is nothing minus + + align:start position:0% +is nothing minus + + + align:start position:0% +is nothing minus +one all + + align:start position:0% +one all + + + align:start position:0% +one all +right and I'm doing thetas here so I can + + align:start position:0% +right and I'm doing thetas here so I can + + + align:start position:0% +right and I'm doing thetas here so I can +forget the low order term + + align:start position:0% +forget the low order term + + + align:start position:0% +forget the low order term +terms so I get X log X + 1 - + + align:start position:0% +terms so I get X log X + 1 - + + + align:start position:0% +terms so I get X log X + 1 - +x this is the only term that survives X + + align:start position:0% +x this is the only term that survives X + + + align:start position:0% +x this is the only term that survives X +log + + align:start position:0% + + + + align:start position:0% + +X and that's + + align:start position:0% +X and that's + + + align:start position:0% +X and that's +right T of n is fact Tilda n log n so in + + align:start position:0% +right T of n is fact Tilda n log n so in + + + align:start position:0% +right T of n is fact Tilda n log n so in +fact it's Theta n log + + align:start position:0% +fact it's Theta n log + + + align:start position:0% +fact it's Theta n log +n + + align:start position:0% +n + + + align:start position:0% +n +okay now in this case going through the + + align:start position:0% +okay now in this case going through the + + + align:start position:0% +okay now in this case going through the +integral and all that maybe that was + + align:start position:0% +integral and all that maybe that was + + + align:start position:0% +integral and all that maybe that was +harder than just guessing and verifying + + align:start position:0% +harder than just guessing and verifying + + + align:start position:0% +harder than just guessing and verifying +you know and and by the way guess and + + align:start position:0% +you know and and by the way guess and + + + align:start position:0% +you know and and by the way guess and +verify got it really the exact + + align:start position:0% +verify got it really the exact + + + align:start position:0% +verify got it really the exact +answer um the nice thing + + align:start position:0% +answer um the nice thing + + + align:start position:0% +answer um the nice thing +is this works for the nasty guys + + align:start position:0% +is this works for the nasty guys + + + align:start position:0% +is this works for the nasty guys +too in + + align:start position:0% +too in + + + align:start position:0% +too in +fact let's figure out the solution to + + align:start position:0% +fact let's figure out the solution to + + + align:start position:0% +fact let's figure out the solution to +this + + align:start position:0% +this + + + align:start position:0% +this +thing which I guarantee you is a pain to + + align:start position:0% +thing which I guarantee you is a pain to + + + align:start position:0% +thing which I guarantee you is a pain to +do without this method + + align:start position:0% + + + + align:start position:0% + +all right the first thing to do is + + align:start position:0% +all right the first thing to do is + + + align:start position:0% +all right the first thing to do is +compute + + align:start position:0% +compute + + + align:start position:0% +compute +P so to do that we need to find a p such + + align:start position:0% +P so to do that we need to find a p such + + + align:start position:0% +P so to do that we need to find a p such +that + + align:start position:0% +that + + + align:start position:0% +that +two * 12 the p + 8 + + align:start position:0% + + + + align:start position:0% + +9th * 3/4 to the + + align:start position:0% + + + + align:start position:0% + +P equals 1 I got a find a p for which + + align:start position:0% +P equals 1 I got a find a p for which + + + align:start position:0% +P equals 1 I got a find a p for which +that's + + align:start position:0% +that's + + + align:start position:0% +that's +true any guesses what P + + align:start position:0% + + + + align:start position:0% + +Works P equals 1 not going to do + + align:start position:0% + + + + align:start position:0% + +it P = + + align:start position:0% +it P = + + + align:start position:0% +it P = +2 let's try + + align:start position:0% +2 let's try + + + align:start position:0% +2 let's try +that I'd have 2 * a + + align:start position:0% +that I'd have 2 * a + + + align:start position:0% +that I'd have 2 * a +quarter Plus 8 9 * 916 + + align:start position:0% +quarter Plus 8 9 * 916 + + + align:start position:0% +quarter Plus 8 9 * 916 +that looks pretty good I get a half plus + + align:start position:0% +that looks pretty good I get a half plus + + + align:start position:0% +that looks pretty good I get a half plus +a half equals + + align:start position:0% +a half equals + + + align:start position:0% +a half equals +1 so P equals 2 + + align:start position:0% +1 so P equals 2 + + + align:start position:0% +1 so P equals 2 +works all + + align:start position:0% +works all + + + align:start position:0% +works all +right all right so let's do the + + align:start position:0% + + + + align:start position:0% + +integral + + align:start position:0% +integral + + + align:start position:0% +integral +TX is Theta of X the p + x the P * the + + align:start position:0% +TX is Theta of X the p + x the P * the + + + align:start position:0% +TX is Theta of X the p + x the P * the +integral all right what is g of X in + + align:start position:0% +integral all right what is g of X in + + + align:start position:0% +integral all right what is g of X in +this thing + + align:start position:0% +this thing + + + align:start position:0% +this thing +X squar so the integral is 1 to x g of U + + align:start position:0% +X squar so the integral is 1 to x g of U + + + align:start position:0% +X squar so the integral is 1 to x g of U +is u^2 divided + + align:start position:0% +is u^2 divided + + + align:start position:0% +is u^2 divided +by U to the 1 + + + align:start position:0% +by U to the 1 + + + + align:start position:0% +by U to the 1 + +p u to the 1 + 2 is just U + + align:start position:0% + + + + align:start position:0% + +cubed all right this is Theta x^2 + x^2 + + align:start position:0% +cubed all right this is Theta x^2 + x^2 + + + align:start position:0% +cubed all right this is Theta x^2 + x^2 +times well the integral of one over U is + + align:start position:0% +times well the integral of one over U is + + + align:start position:0% +times well the integral of one over U is +just log of U + + align:start position:0% + + + + align:start position:0% + +and that's just log of + + align:start position:0% +and that's just log of + + + align:start position:0% +and that's just log of +x so the answer is x square Ln of X + + align:start position:0% +x so the answer is x square Ln of X + + + align:start position:0% +x so the answer is x square Ln of X +done so that's pretty good what these + + align:start position:0% +done so that's pretty good what these + + + align:start position:0% +done so that's pretty good what these +guys + + align:start position:0% +guys + + + align:start position:0% +guys +did in fact that + + align:start position:0% +did in fact that + + + align:start position:0% +did in fact that +is uh that is the correct + + align:start position:0% +is uh that is the correct + + + align:start position:0% +is uh that is the correct +answer all right so really easy to plug + + align:start position:0% +answer all right so really easy to plug + + + align:start position:0% +answer all right so really easy to plug +in any + + align:start position:0% +in any + + + align:start position:0% +in any +questions on that + + align:start position:0% + + + + align:start position:0% + +yeah it doesn't give you the actual + + align:start position:0% +yeah it doesn't give you the actual + + + align:start position:0% +yeah it doesn't give you the actual +number it just gives you the ASM totic + + align:start position:0% +number it just gives you the ASM totic + + + align:start position:0% +number it just gives you the ASM totic +growth all you know is that the limit of + + align:start position:0% +growth all you know is that the limit of + + + align:start position:0% +growth all you know is that the limit of +TX over x^2 Ln of X is less than + + align:start position:0% +TX over x^2 Ln of X is less than + + + align:start position:0% +TX over x^2 Ln of X is less than +infinity and bigger than zero so it's + + align:start position:0% +infinity and bigger than zero so it's + + + align:start position:0% +infinity and bigger than zero so it's +growing as this you don't know if it's + + align:start position:0% +growing as this you don't know if it's + + + align:start position:0% +growing as this you don't know if it's +10 X2 l x or a million x s l x on the + + align:start position:0% +10 X2 l x or a million x s l x on the + + + align:start position:0% +10 X2 l x or a million x s l x on the +other hand for algorithms + + align:start position:0% +other hand for algorithms + + + align:start position:0% +other hand for algorithms +usually you're forgetting the constant + + align:start position:0% +usually you're forgetting the constant + + + align:start position:0% +usually you're forgetting the constant +factors anyway because they depend on + + align:start position:0% +factors anyway because they depend on + + + align:start position:0% +factors anyway because they depend on +things to do with the CPU you're using + + align:start position:0% +things to do with the CPU you're using + + + align:start position:0% +things to do with the CPU you're using +and stuff like that what you really care + + align:start position:0% +and stuff like that what you really care + + + align:start position:0% +and stuff like that what you really care +about often when you're studying + + align:start position:0% +about often when you're studying + + + align:start position:0% +about often when you're studying +algorithms is the ASM totic growth not + + align:start position:0% +algorithms is the ASM totic growth not + + + align:start position:0% +algorithms is the ASM totic growth not +the actual value + + align:start position:0% +the actual value + + + align:start position:0% +the actual value +yeah natural log is B log Bas e and then + + align:start position:0% +yeah natural log is B log Bas e and then + + + align:start position:0% +yeah natural log is B log Bas e and then +above I see using log which as base two + + align:start position:0% +above I see using log which as base two + + + align:start position:0% +above I see using log which as base two +doesn't matter it does up there because + + align:start position:0% +doesn't matter it does up there because + + + align:start position:0% +doesn't matter it does up there because +I've got a Tilda and in the Tilda the + + align:start position:0% +I've got a Tilda and in the Tilda the + + + align:start position:0% +I've got a Tilda and in the Tilda the +constant Factor matters it doesn't + + align:start position:0% +constant Factor matters it doesn't + + + align:start position:0% +constant Factor matters it doesn't +matter in here because log base 2 and + + align:start position:0% +matter in here because log base 2 and + + + align:start position:0% +matter in here because log base 2 and +log base e are within a constant Factor + + align:start position:0% +log base e are within a constant Factor + + + align:start position:0% +log base e are within a constant Factor +namely log of two L of two is the + + align:start position:0% +namely log of two L of two is the + + + align:start position:0% +namely log of two L of two is the +constant Factor so logs don't matter + + align:start position:0% +constant Factor so logs don't matter + + + align:start position:0% +constant Factor so logs don't matter +what the base is once you're inside a + + align:start position:0% +what the base is once you're inside a + + + align:start position:0% +what the base is once you're inside a +Theta or an o or that kind of thing in a + + align:start position:0% +Theta or an o or that kind of thing in a + + + align:start position:0% +Theta or an o or that kind of thing in a +Tilda they matter because the constant + + align:start position:0% +Tilda they matter because the constant + + + align:start position:0% +Tilda they matter because the constant +Factor matters + + align:start position:0% + + + + align:start position:0% + +yeah yeah because x s is small compared + + align:start position:0% +yeah yeah because x s is small compared + + + align:start position:0% +yeah yeah because x s is small compared +to X2 Ln of X because it's all by + + align:start position:0% + + + + align:start position:0% + +theeta no uh you could put all sorts of + + align:start position:0% +theeta no uh you could put all sorts of + + + align:start position:0% +theeta no uh you could put all sorts of +other stuff in here and it doesn't + + align:start position:0% +other stuff in here and it doesn't + + + align:start position:0% +other stuff in here and it doesn't +matter because it still equals Theta of + + align:start position:0% +matter because it still equals Theta of + + + align:start position:0% +matter because it still equals Theta of +x^2 Ln of X there's no hidden meanings + + align:start position:0% +x^2 Ln of X there's no hidden meanings + + + align:start position:0% +x^2 Ln of X there's no hidden meanings +by having extra stuff in here okay + + align:start position:0% +by having extra stuff in here okay + + + align:start position:0% +by having extra stuff in here okay +that's that's important in this case + + align:start position:0% +that's that's important in this case + + + align:start position:0% +that's that's important in this case +when you put more stuff in the Theta + + align:start position:0% +when you put more stuff in the Theta + + + align:start position:0% +when you put more stuff in the Theta +doesn't mean a + + align:start position:0% +doesn't mean a + + + align:start position:0% +doesn't mean a +thing any other questions yeah + + align:start position:0% + + + + align:start position:0% + +ah good question um well let's see it + + align:start position:0% +ah good question um well let's see it + + + align:start position:0% +ah good question um well let's see it +goes back to over here if I + + align:start position:0% +goes back to over here if I + + + align:start position:0% +goes back to over here if I +make + + align:start position:0% +make + + + align:start position:0% +make +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +p if I make see the B's are between zero + + align:start position:0% +p if I make see the B's are between zero + + + align:start position:0% +p if I make see the B's are between zero +and one by making P big enough I drive + + align:start position:0% +and one by making P big enough I drive + + + align:start position:0% +and one by making P big enough I drive +the value down by making P be larger + + align:start position:0% +the value down by making P be larger + + + align:start position:0% +the value down by making P be larger +than negative I draw the value up so + + align:start position:0% +than negative I draw the value up so + + + align:start position:0% +than negative I draw the value up so +there's some value of P but that's a + + align:start position:0% +there's some value of P but that's a + + + align:start position:0% +there's some value of P but that's a +good question let's see what happens + + align:start position:0% +good question let's see what happens + + + align:start position:0% +good question let's see what happens +when p is not so nice because the + + align:start position:0% +when p is not so nice because the + + + align:start position:0% +when p is not so nice because the +examples I gave you in one case P was + + align:start position:0% +examples I gave you in one case P was + + + align:start position:0% +examples I gave you in one case P was +one and one p was two sort of nice let's + + align:start position:0% +one and one p was two sort of nice let's + + + align:start position:0% +one and one p was two sort of nice let's +look at a bad case + + align:start position:0% + + + + align:start position:0% + +there let's look at this + + align:start position:0% + + + + align:start position:0% + +recurrence 3 T of X over 3 plus 4 T of X + + align:start position:0% +recurrence 3 T of X over 3 plus 4 T of X + + + align:start position:0% +recurrence 3 T of X over 3 plus 4 T of X +over + + align:start position:0% +over + + + align:start position:0% +over +4 plus + + align:start position:0% +4 plus + + + align:start position:0% +4 plus +x^2 all right so that's the recurrence + + align:start position:0% +x^2 all right so that's the recurrence + + + align:start position:0% +x^2 all right so that's the recurrence +and first step is to compute p and this + + align:start position:0% +and first step is to compute p and this + + + align:start position:0% +and first step is to compute p and this +time it's not going to be + + align:start position:0% +time it's not going to be + + + align:start position:0% +time it's not going to be +nice all right so I need to find a p + + align:start position:0% +nice all right so I need to find a p + + + align:start position:0% +nice all right so I need to find a p +such that 3 * a thir the P plus 4 * a 4 + + align:start position:0% +such that 3 * a thir the P plus 4 * a 4 + + + align:start position:0% +such that 3 * a thir the P plus 4 * a 4 +to the + + align:start position:0% +to the + + + align:start position:0% +to the +P equal + + align:start position:0% +P equal + + + align:start position:0% +P equal +1 and you might say okay let's try P + + align:start position:0% +1 and you might say okay let's try P + + + align:start position:0% +1 and you might say okay let's try P +equals + + align:start position:0% + + + + align:start position:0% + +1 I get 1 + 1 is two that's too + + align:start position:0% +1 I get 1 + 1 is two that's too + + + align:start position:0% +1 I get 1 + 1 is two that's too +big so which way do I have to go on P do + + align:start position:0% +big so which way do I have to go on P do + + + align:start position:0% +big so which way do I have to go on P do +I need a bigger P or a smaller + + align:start position:0% +I need a bigger P or a smaller + + + align:start position:0% +I need a bigger P or a smaller +P bigger because I gotta get from two + + align:start position:0% +P bigger because I gotta get from two + + + align:start position:0% +P bigger because I gotta get from two +down to one so I gotta I know that P is + + align:start position:0% +down to one so I gotta I know that P is + + + align:start position:0% +down to one so I gotta I know that P is +bigger than + + align:start position:0% + + + + align:start position:0% + +one all right so the next thing to try + + align:start position:0% +one all right so the next thing to try + + + align:start position:0% +one all right so the next thing to try +would be hoping the world is nice P + + align:start position:0% +would be hoping the world is nice P + + + align:start position:0% +would be hoping the world is nice P +equals + + align:start position:0% +equals + + + align:start position:0% +equals +2 fact maybe I'll do that over here + + align:start position:0% +2 fact maybe I'll do that over here + + + align:start position:0% +2 fact maybe I'll do that over here +let's try P equal + + align:start position:0% + + + + align:start position:0% + +2 so I get 3 * a 9th + 4 * the + + align:start position:0% +2 so I get 3 * a 9th + 4 * the + + + align:start position:0% +2 so I get 3 * a 9th + 4 * the +16th and that equals A3 + a + + align:start position:0% +16th and that equals A3 + a + + + align:start position:0% +16th and that equals A3 + a +4th that's less than + + align:start position:0% +4th that's less than + + + align:start position:0% +4th that's less than +one that didn't work what do I have to + + align:start position:0% +one that didn't work what do I have to + + + align:start position:0% +one that didn't work what do I have to +do now with p is it bigger than two or + + align:start position:0% +do now with p is it bigger than two or + + + align:start position:0% +do now with p is it bigger than two or +less than + + align:start position:0% +less than + + + align:start position:0% +less than +two less than + + align:start position:0% + + + + align:start position:0% + +two Ah that's sort of a pain P is + + align:start position:0% +two Ah that's sort of a pain P is + + + align:start position:0% +two Ah that's sort of a pain P is +between one and two so it's not an + + align:start position:0% +between one and two so it's not an + + + align:start position:0% +between one and two so it's not an +integer now you can sort of do divide + + align:start position:0% +integer now you can sort of do divide + + + align:start position:0% +integer now you can sort of do divide +and conquer here next I try p is three + + align:start position:0% +and conquer here next I try p is three + + + align:start position:0% +and conquer here next I try p is three +Hales get my calculator out and see + + align:start position:0% +Hales get my calculator out and see + + + align:start position:0% +Hales get my calculator out and see +which way it goes and you could sort of + + align:start position:0% +which way it goes and you could sort of + + + align:start position:0% +which way it goes and you could sort of +Home in on it but there's something + + align:start position:0% +Home in on it but there's something + + + align:start position:0% +Home in on it but there's something +really nice that happens with + + align:start position:0% +really nice that happens with + + + align:start position:0% +really nice that happens with +acrobat and that is if you ever conclude + + align:start position:0% +acrobat and that is if you ever conclude + + + align:start position:0% +acrobat and that is if you ever conclude +that P is less than your exponent here + + align:start position:0% +that P is less than your exponent here + + + align:start position:0% +that P is less than your exponent here +you don't even have to compute it + + align:start position:0% +you don't even have to compute it + + + align:start position:0% +you don't even have to compute it +all right let's see why Let's do an + + align:start position:0% + + + + align:start position:0% + +example this will happen a + + align:start position:0% +example this will happen a + + + align:start position:0% +example this will happen a +lot there's some P but it's just going + + align:start position:0% +lot there's some P but it's just going + + + align:start position:0% +lot there's some P but it's just going +to be a pain to evaluate but let's see + + align:start position:0% +to be a pain to evaluate but let's see + + + align:start position:0% +to be a pain to evaluate but let's see +what happens + + align:start position:0% +what happens + + + align:start position:0% +what happens +here + + align:start position:0% +here + + + align:start position:0% +here +okay so I'm just going to try to solve + + align:start position:0% +okay so I'm just going to try to solve + + + align:start position:0% +okay so I'm just going to try to solve +it write the solution anyway T ofx + + align:start position:0% +it write the solution anyway T ofx + + + align:start position:0% +it write the solution anyway T ofx +equals Theta X the P plus X the P + + align:start position:0% +equals Theta X the P plus X the P + + + align:start position:0% +equals Theta X the P plus X the P +integral 1 tox what's G of + + align:start position:0% +integral 1 tox what's G of + + + align:start position:0% +integral 1 tox what's G of +X X2 so that's + + align:start position:0% +X X2 so that's + + + align:start position:0% +X X2 so that's +u^2 over u 1 + P I still don't know what + + align:start position:0% +u^2 over u 1 + P I still don't know what + + + align:start position:0% +u^2 over u 1 + P I still don't know what +it is but going to give it a try + + align:start position:0% +it is but going to give it a try + + + align:start position:0% +it is but going to give it a try +here that's Theta x to the P plus X the + + align:start position:0% +here that's Theta x to the P plus X the + + + align:start position:0% +here that's Theta x to the P plus X the +P well this is now the integral of U the + + align:start position:0% +P well this is now the integral of U the + + + align:start position:0% +P well this is now the integral of U the +1 minus P + + align:start position:0% +1 minus P + + + align:start position:0% +1 minus P +du and P is bigger than one I know that + + align:start position:0% +du and P is bigger than one I know that + + + align:start position:0% +du and P is bigger than one I know that +this is Theta x p + x + + align:start position:0% +this is Theta x p + x + + + align:start position:0% +this is Theta x p + x +p well the integral here is x^ the 2 + + align:start position:0% +p well the integral here is x^ the 2 + + + align:start position:0% +p well the integral here is x^ the 2 +minus + + align:start position:0% +minus + + + align:start position:0% +minus +P up to constants I don't even care + + align:start position:0% +P up to constants I don't even care + + + align:start position:0% +P up to constants I don't even care +about dividing by 2 minus P because I + + align:start position:0% +about dividing by 2 minus P because I + + + align:start position:0% +about dividing by 2 minus P because I +got big Theta let's put that P up + + align:start position:0% +got big Theta let's put that P up + + + align:start position:0% +got big Theta let's put that P up +here okay well this equals Theta X the + + align:start position:0% +here okay well this equals Theta X the + + + align:start position:0% +here okay well this equals Theta X the +p+ oh it canceled there x^2 + + align:start position:0% + + + + align:start position:0% + +and what's the answer going to + + align:start position:0% +and what's the answer going to + + + align:start position:0% +and what's the answer going to +be X2 because p is less than two so this + + align:start position:0% +be X2 because p is less than two so this + + + align:start position:0% +be X2 because p is less than two so this +is a small order + + align:start position:0% +is a small order + + + align:start position:0% +is a small order +term so I didn't even know what P was + + align:start position:0% +term so I didn't even know what P was + + + align:start position:0% +term so I didn't even know what P was +just that it was less than two and I got + + align:start position:0% +just that it was less than two and I got + + + align:start position:0% +just that it was less than two and I got +the answer and what do you know the + + align:start position:0% +the answer and what do you know the + + + align:start position:0% +the answer and what do you know the +answer was just this thing that's sort + + align:start position:0% +answer was just this thing that's sort + + + align:start position:0% +answer was just this thing that's sort +of nice and simple and in fact that's a + + align:start position:0% +of nice and simple and in fact that's a + + + align:start position:0% +of nice and simple and in fact that's a +theorem right which will state in + + align:start position:0% +theorem right which will state in + + + align:start position:0% +theorem right which will state in +general + + align:start position:0% + + + + align:start position:0% + +if G of x equals Theta x to the T for + + align:start position:0% +if G of x equals Theta x to the T for + + + align:start position:0% +if G of x equals Theta x to the T for +some T bigger than equal to + + align:start position:0% + + + + align:start position:0% + +zero and when you plug that value in and + + align:start position:0% +zero and when you plug that value in and + + + align:start position:0% +zero and when you plug that value in and +take your + + align:start position:0% +take your + + + align:start position:0% +take your +sum Computing trying to compute the P + + align:start position:0% +sum Computing trying to compute the P + + + align:start position:0% +sum Computing trying to compute the P +value so I take AI * B to the T and that + + align:start position:0% +value so I take AI * B to the T and that + + + align:start position:0% +value so I take AI * B to the T and that +comes out to be less than one like it + + align:start position:0% +comes out to be less than one like it + + + align:start position:0% +comes out to be less than one like it +did here when I plugged + + align:start position:0% +did here when I plugged + + + align:start position:0% +did here when I plugged +in I plugged in P equal 2 and I computed + + align:start position:0% +in I plugged in P equal 2 and I computed + + + align:start position:0% +in I plugged in P equal 2 and I computed +it and I was less than one right but if + + align:start position:0% +it and I was less than one right but if + + + align:start position:0% +it and I was less than one right but if +that happens in + + align:start position:0% +that happens in + + + align:start position:0% +that happens in +general + + align:start position:0% +general + + + align:start position:0% +general +then the answer + + align:start position:0% + + + + align:start position:0% + +is Theta G of + + align:start position:0% +is Theta G of + + + align:start position:0% +is Theta G of +X plain and simple it just turns out to + + align:start position:0% +X plain and simple it just turns out to + + + align:start position:0% +X plain and simple it just turns out to +be + + align:start position:0% +be + + + align:start position:0% +be +the the G of X term up to constant + + align:start position:0% +the the G of X term up to constant + + + align:start position:0% +the the G of X term up to constant +factors so you don't even have to + + align:start position:0% +factors so you don't even have to + + + align:start position:0% +factors so you don't even have to +compute it just do that check on the + + align:start position:0% +compute it just do that check on the + + + align:start position:0% +compute it just do that check on the +power here to see is it smaller than + + align:start position:0% +power here to see is it smaller than + + + align:start position:0% +power here to see is it smaller than +that I won't prove that there actually + + align:start position:0% +that I won't prove that there actually + + + align:start position:0% +that I won't prove that there actually +not hard to do it's the proof is pretty + + align:start position:0% +not hard to do it's the proof is pretty + + + align:start position:0% +not hard to do it's the proof is pretty +much what I did with this example so + + align:start position:0% +much what I did with this example so + + + align:start position:0% +much what I did with this example so +it's not too + + align:start position:0% + + + + align:start position:0% + +hard okay any + + align:start position:0% + + + + align:start position:0% + +questions I want to show you one more + + align:start position:0% +questions I want to show you one more + + + align:start position:0% +questions I want to show you one more +thing but just make sure that's okay and + + align:start position:0% +thing but just make sure that's okay and + + + align:start position:0% +thing but just make sure that's okay and +this is + + align:start position:0% +this is + + + align:start position:0% +this is +something never to + + align:start position:0% +something never to + + + align:start position:0% +something never to +do um with the ASM totic notation like + + align:start position:0% +do um with the ASM totic notation like + + + align:start position:0% +do um with the ASM totic notation like +we talked about last + + align:start position:0% +we talked about last + + + align:start position:0% +we talked about last +time when you're using acrobot and when + + align:start position:0% +time when you're using acrobot and when + + + align:start position:0% +time when you're using acrobot and when +you're doing occurrences with algorithms + + align:start position:0% +you're doing occurrences with algorithms + + + align:start position:0% +you're doing occurrences with algorithms +you always are using ASM totic + + align:start position:0% +you always are using ASM totic + + + align:start position:0% +you always are using ASM totic +notation right your answer is Theta of + + align:start position:0% +notation right your answer is Theta of + + + align:start position:0% +notation right your answer is Theta of +something and in fact what'll start + + align:start position:0% +something and in fact what'll start + + + align:start position:0% +something and in fact what'll start +happening as you do this + + align:start position:0% +happening as you do this + + + align:start position:0% +happening as you do this +stuff because the constant factors don't + + align:start position:0% +stuff because the constant factors don't + + + align:start position:0% +stuff because the constant factors don't +matter they just because you're wiping + + align:start position:0% +matter they just because you're wiping + + + align:start position:0% +matter they just because you're wiping +them out in the Theta notation + + align:start position:0% +them out in the Theta notation + + + align:start position:0% +them out in the Theta notation +what you'll see is things like this your + + align:start position:0% +what you'll see is things like this your + + + align:start position:0% +what you'll see is things like this your +recurrence will be set up to be T of n + + align:start position:0% +recurrence will be set up to be T of n + + + align:start position:0% +recurrence will be set up to be T of n +is 2 T of n / 2 plus o of n or plus + + align:start position:0% +is 2 T of n / 2 plus o of n or plus + + + align:start position:0% +is 2 T of n / 2 plus o of n or plus +Theta of + + align:start position:0% +Theta of + + + align:start position:0% +Theta of +N and then you'll + + align:start position:0% +N and then you'll + + + align:start position:0% +N and then you'll +conclude that t of n is Theta of n log + + align:start position:0% +conclude that t of n is Theta of n log + + + align:start position:0% +conclude that t of n is Theta of n log +n using acrobot or whatever method you + + align:start position:0% +n using acrobot or whatever method you + + + align:start position:0% +n using acrobot or whatever method you +want all right so this because it + + align:start position:0% +want all right so this because it + + + align:start position:0% +want all right so this because it +doesn't really matter what the constant + + align:start position:0% +doesn't really matter what the constant + + + align:start position:0% +doesn't really matter what the constant +is on + + align:start position:0% +is on + + + align:start position:0% +is on +G because the answer the constants + + align:start position:0% +G because the answer the constants + + + align:start position:0% +G because the answer the constants +disapp + + align:start position:0% +disapp + + + align:start position:0% +disapp +appear doesn't matter and so people stop + + align:start position:0% +appear doesn't matter and so people stop + + + align:start position:0% +appear doesn't matter and so people stop +worrying about it early + + align:start position:0% +worrying about it early + + + align:start position:0% +worrying about it early +on all right now here's the bad + + align:start position:0% + + + + align:start position:0% + +example let me show you a false proof + + align:start position:0% +example let me show you a false proof + + + align:start position:0% +example let me show you a false proof +like last + + align:start position:0% +like last + + + align:start position:0% +like last +time and this time I think it'll be + + align:start position:0% +time and this time I think it'll be + + + align:start position:0% +time and this time I think it'll be +pretty easy to spot the flaw + + align:start position:0% + + + + align:start position:0% + +okay theorem + + align:start position:0% + + + + align:start position:0% + +not if T of n = 2 T of n / 2 + n minus1 + + align:start position:0% +not if T of n = 2 T of n / 2 + n minus1 + + + align:start position:0% +not if T of n = 2 T of n / 2 + n minus1 +this is the recurrence we had for merge + + align:start position:0% +this is the recurrence we had for merge + + + align:start position:0% +this is the recurrence we had for merge +sort and T of 1 equals + + align:start position:0% +sort and T of 1 equals + + + align:start position:0% +sort and T of 1 equals +zero then I'm going to prove + + align:start position:0% +zero then I'm going to prove + + + align:start position:0% +zero then I'm going to prove +that t of n is O of + + align:start position:0% + + + + align:start position:0% + +n now that can't be + + align:start position:0% +n now that can't be + + + align:start position:0% +n now that can't be +right right because we've proved it's + + align:start position:0% +right right because we've proved it's + + + align:start position:0% +right right because we've proved it's +Theta of n log n til of n log n and that + + align:start position:0% +Theta of n log n til of n log n and that + + + align:start position:0% +Theta of n log n til of n log n and that +is not o of n right and log n grows + + align:start position:0% +is not o of n right and log n grows + + + align:start position:0% +is not o of n right and log n grows +faster than + + align:start position:0% +faster than + + + align:start position:0% +faster than +n all right but let's see the + + align:start position:0% + + + + align:start position:0% + +proof by strong induction + + align:start position:0% + + + + align:start position:0% + +the induction + + align:start position:0% +the induction + + + align:start position:0% +the induction +hypothesis is going to be what we're + + align:start position:0% +hypothesis is going to be what we're + + + align:start position:0% +hypothesis is going to be what we're +trying to + + align:start position:0% + + + + align:start position:0% + +prove + + align:start position:0% + + + + align:start position:0% + +okay base + + align:start position:0% +okay base + + + align:start position:0% +okay base +case Nal 1 T of 1 is zero zero is surely + + align:start position:0% +case Nal 1 T of 1 is zero zero is surely + + + align:start position:0% +case Nal 1 T of 1 is zero zero is surely +o of + + align:start position:0% + + + + align:start position:0% + +one the induction + + align:start position:0% + + + + align:start position:0% + +step all right we're going to assume P1 + + align:start position:0% +step all right we're going to assume P1 + + + align:start position:0% +step all right we're going to assume P1 +P2 P3 up to PN minus one to prove PN + + align:start position:0% + + + + align:start position:0% + +all right and let's look at P of n so I + + align:start position:0% +all right and let's look at P of n so I + + + align:start position:0% +all right and let's look at P of n so I +look at + + align:start position:0% +look at + + + align:start position:0% +look at +TN is 2 T of n / + + align:start position:0% +TN is 2 T of n / + + + align:start position:0% +TN is 2 T of n / +2 plus + + align:start position:0% +2 plus + + + align:start position:0% +2 plus +nus1 induction hypothesis on N /2 says + + align:start position:0% +nus1 induction hypothesis on N /2 says + + + align:start position:0% +nus1 induction hypothesis on N /2 says +this is 2 * o of n + + align:start position:0% +this is 2 * o of n + + + align:start position:0% +this is 2 * o of n +/2 plus n minus + + align:start position:0% +/2 plus n minus + + + align:start position:0% +/2 plus n minus +one twice o of n over two is O of n plus + + align:start position:0% +one twice o of n over two is O of n plus + + + align:start position:0% +one twice o of n over two is O of n plus +n is O of n this is O of N and I'm + + align:start position:0% +n is O of n this is O of N and I'm + + + align:start position:0% +n is O of n this is O of N and I'm +done I just proved the of n is O of + + align:start position:0% + + + + align:start position:0% + +n all right what's the bad step what's + + align:start position:0% +n all right what's the bad step what's + + + align:start position:0% +n all right what's the bad step what's +the + + align:start position:0% +the + + + align:start position:0% +the +bug see the bug what is + + align:start position:0% +bug see the bug what is + + + align:start position:0% +bug see the bug what is +it induction hypothesis what's wrong + + align:start position:0% +it induction hypothesis what's wrong + + + align:start position:0% +it induction hypothesis what's wrong +with + + align:start position:0% + + + + align:start position:0% + +that right the N from the predicate + + align:start position:0% +that right the N from the predicate + + + align:start position:0% +that right the N from the predicate +cannot be in the O of n right because + + align:start position:0% +cannot be in the O of n right because + + + align:start position:0% +cannot be in the O of n right because +remember o of N means this statement + + align:start position:0% +remember o of N means this statement + + + align:start position:0% +remember o of N means this statement +here by it itself means the limit as n + + align:start position:0% +here by it itself means the limit as n + + + align:start position:0% +here by it itself means the limit as n +goes to Infinity of T of n/ n is less + + align:start position:0% +goes to Infinity of T of n/ n is less + + + align:start position:0% +goes to Infinity of T of n/ n is less +than + + align:start position:0% +than + + + align:start position:0% +than +infinity okay but the limit this makes + + align:start position:0% +infinity okay but the limit this makes + + + align:start position:0% +infinity okay but the limit this makes +no sense if I specified n in a + + align:start position:0% +no sense if I specified n in a + + + align:start position:0% +no sense if I specified n in a +predicate so what's the rule same rule + + align:start position:0% +predicate so what's the rule same rule + + + align:start position:0% +predicate so what's the rule same rule +as last time same bug what's the + + align:start position:0% + + + + align:start position:0% + +rule never do ASM totic notation and + + align:start position:0% +rule never do ASM totic notation and + + + align:start position:0% +rule never do ASM totic notation and +induction hypothesis never mix Big O and + + align:start position:0% +induction hypothesis never mix Big O and + + + align:start position:0% +induction hypothesis never mix Big O and +a predicate never ever it looks so nice + + align:start position:0% +a predicate never ever it looks so nice + + + align:start position:0% +a predicate never ever it looks so nice +to do but it is so wrong it just makes + + align:start position:0% +to do but it is so wrong it just makes + + + align:start position:0% +to do but it is so wrong it just makes +nonsense all right very good so um + + align:start position:0% +nonsense all right very good so um + + + align:start position:0% +nonsense all right very good so um +remember ice cream tonight recitation + + align:start position:0% +remember ice cream tonight recitation + + + align:start position:0% +remember ice cream tonight recitation +optional tomorrow but study session is + + align:start position:0% +optional tomorrow but study session is + + + align:start position:0% +optional tomorrow but study session is +there \ No newline at end of file diff --git a/LGm2fvo-M9g.txt b/LGm2fvo-M9g.txt new file mode 100644 index 0000000000000000000000000000000000000000..348712fe9417447678f970131ef66f9a0a984a55 --- /dev/null +++ b/LGm2fvo-M9g.txt @@ -0,0 +1,1043 @@ +align:start position:0% + +hello and welcome back to 8701 + + align:start position:0% +hello and welcome back to 8701 + + + align:start position:0% +hello and welcome back to 8701 +um in this class we'll talk about spin + + align:start position:0% +um in this class we'll talk about spin + + + align:start position:0% +um in this class we'll talk about spin +um if you remember the discussion on + + align:start position:0% +um if you remember the discussion on + + + align:start position:0% +um if you remember the discussion on +relativistic kinematics we had + + align:start position:0% +relativistic kinematics we had + + + align:start position:0% +relativistic kinematics we had +last week you notice that + + align:start position:0% +last week you notice that + + + align:start position:0% +last week you notice that +i discussed a decay + + align:start position:0% +i discussed a decay + + + align:start position:0% +i discussed a decay +of a pion say a neutral ion + + align:start position:0% +of a pion say a neutral ion + + + align:start position:0% +of a pion say a neutral ion +into an electron and a positron and an + + align:start position:0% +into an electron and a positron and an + + + align:start position:0% +into an electron and a positron and an +electron + + align:start position:0% +electron + + + align:start position:0% +electron +um and we were able to calculate the + + align:start position:0% +um and we were able to calculate the + + + align:start position:0% +um and we were able to calculate the +velocity of those two particles the + + align:start position:0% +velocity of those two particles the + + + align:start position:0% +velocity of those two particles the +electron and the positron + + align:start position:0% +electron and the positron + + + align:start position:0% +electron and the positron +quite easily by knowing the mass of the + + align:start position:0% +quite easily by knowing the mass of the + + + align:start position:0% +quite easily by knowing the mass of the +pion and the masses of the electron and + + align:start position:0% +pion and the masses of the electron and + + + align:start position:0% +pion and the masses of the electron and +the positron + + align:start position:0% +the positron + + + align:start position:0% +the positron +you put yourself into the rest frame of + + align:start position:0% +you put yourself into the rest frame of + + + align:start position:0% +you put yourself into the rest frame of +the ion and you can calculate those + + align:start position:0% +the ion and you can calculate those + + + align:start position:0% +the ion and you can calculate those +velocity + + align:start position:0% +velocity + + + align:start position:0% +velocity +i also told you that this decay is + + align:start position:0% +i also told you that this decay is + + + align:start position:0% +i also told you that this decay is +highly suppressed because of the spins + + align:start position:0% +highly suppressed because of the spins + + + align:start position:0% +highly suppressed because of the spins +of the particles involved the pion has a + + align:start position:0% +of the particles involved the pion has a + + + align:start position:0% +of the particles involved the pion has a +spin + + align:start position:0% +spin + + + align:start position:0% +spin +zero and the electron and the position + + align:start position:0% +zero and the electron and the position + + + align:start position:0% +zero and the electron and the position +have spin one half + + align:start position:0% +have spin one half + + + align:start position:0% +have spin one half +but it is not easily possible to align + + align:start position:0% +but it is not easily possible to align + + + align:start position:0% +but it is not easily possible to align +the electron in the positron such that + + align:start position:0% +the electron in the positron such that + + + align:start position:0% +the electron in the positron such that +the spins align + + align:start position:0% +the spins align + + + align:start position:0% +the spins align +to zero so therefore this decay is not + + align:start position:0% +to zero so therefore this decay is not + + + align:start position:0% +to zero so therefore this decay is not +easily possible let's dive a little bit + + align:start position:0% +easily possible let's dive a little bit + + + align:start position:0% +easily possible let's dive a little bit +into this + + align:start position:0% +into this + + + align:start position:0% +into this +um in quantum mechanics the spin of a + + align:start position:0% +um in quantum mechanics the spin of a + + + align:start position:0% +um in quantum mechanics the spin of a +particle + + align:start position:0% +particle + + + align:start position:0% +particle +of a particle with a vector can is + + align:start position:0% +of a particle with a vector can is + + + align:start position:0% +of a particle with a vector can is +quantized in terms of its length and its + + align:start position:0% +quantized in terms of its length and its + + + align:start position:0% +quantized in terms of its length and its +components + + align:start position:0% +components + + + align:start position:0% +components +we calculate the length of this in + + align:start position:0% +we calculate the length of this in + + + align:start position:0% +we calculate the length of this in +vector s we find that the square root + + align:start position:0% +vector s we find that the square root + + + align:start position:0% +vector s we find that the square root +of s times s plus 1 in units of h bar + + align:start position:0% +of s times s plus 1 in units of h bar + + + align:start position:0% +of s times s plus 1 in units of h bar +the component then along the any axis + + align:start position:0% +the component then along the any axis + + + align:start position:0% +the component then along the any axis +actually + + align:start position:0% +actually + + + align:start position:0% +actually +and in this case here the z-axis have + + align:start position:0% +and in this case here the z-axis have + + + align:start position:0% +and in this case here the z-axis have +eigenvalues + + align:start position:0% +eigenvalues + + + align:start position:0% +eigenvalues +and we you know they're listed here um + + align:start position:0% +and we you know they're listed here um + + + align:start position:0% +and we you know they're listed here um +and we find that there's two s plus one + + align:start position:0% +and we find that there's two s plus one + + + align:start position:0% +and we find that there's two s plus one +possible values + + align:start position:0% +possible values + + + align:start position:0% +possible values +so i'll pick here just arbitrarily the + + align:start position:0% +so i'll pick here just arbitrarily the + + + align:start position:0% +so i'll pick here just arbitrarily the +z-axis + + align:start position:0% +z-axis + + + align:start position:0% +z-axis +but the question is an obvious question + + align:start position:0% +but the question is an obvious question + + + align:start position:0% +but the question is an obvious question +um + + align:start position:0% +um + + + align:start position:0% +um +which access is a sendable choice for + + align:start position:0% +which access is a sendable choice for + + + align:start position:0% +which access is a sendable choice for +this problem + + align:start position:0% +this problem + + + align:start position:0% +this problem +so i want you to actually stop here + + align:start position:0% + + + + align:start position:0% + +and think about this what are sensible + + align:start position:0% +and think about this what are sensible + + + align:start position:0% +and think about this what are sensible +options + + align:start position:0% + + + + align:start position:0% + +you know if you want to get an + + align:start position:0% +you know if you want to get an + + + align:start position:0% +you know if you want to get an +eigenvalue the physical states of + + align:start position:0% +eigenvalue the physical states of + + + align:start position:0% +eigenvalue the physical states of +particles + + align:start position:0% +particles + + + align:start position:0% +particles +um which axes are the right ones to + + align:start position:0% +um which axes are the right ones to + + + align:start position:0% +um which axes are the right ones to +choose + + align:start position:0% +choose + + + align:start position:0% +choose +or sensible you know there's no right + + align:start position:0% +or sensible you know there's no right + + + align:start position:0% +or sensible you know there's no right +and one in this discussion + + align:start position:0% +and one in this discussion + + + align:start position:0% +and one in this discussion +let me motivate this um if you look at + + align:start position:0% +let me motivate this um if you look at + + + align:start position:0% +let me motivate this um if you look at +the orbital momentum of a particle + + align:start position:0% +the orbital momentum of a particle + + + align:start position:0% +the orbital momentum of a particle +that's given by + + align:start position:0% +that's given by + + + align:start position:0% +that's given by +r cross p where p is the momentum vector + + align:start position:0% +r cross p where p is the momentum vector + + + align:start position:0% +r cross p where p is the momentum vector +of the particle + + align:start position:0% +of the particle + + + align:start position:0% +of the particle +so now if you're looking at the total + + align:start position:0% +so now if you're looking at the total + + + align:start position:0% +so now if you're looking at the total +momentum we have to add + + align:start position:0% +momentum we have to add + + + align:start position:0% +momentum we have to add +the longer the angular momentum and the + + align:start position:0% +the longer the angular momentum and the + + + align:start position:0% +the longer the angular momentum and the +spin of the particle together + + align:start position:0% +spin of the particle together + + + align:start position:0% +spin of the particle together +so as shown in this picture here + + align:start position:0% + + + + align:start position:0% + +you see that the parallel component + + align:start position:0% +you see that the parallel component + + + align:start position:0% +you see that the parallel component +the component in parallel to the fly + + align:start position:0% +the component in parallel to the fly + + + align:start position:0% +the component in parallel to the fly +direction + + align:start position:0% +direction + + + align:start position:0% +direction +is zero by definition because the cross + + align:start position:0% +is zero by definition because the cross + + + align:start position:0% +is zero by definition because the cross +product + + align:start position:0% +product + + + align:start position:0% +product +is defined the longer + + align:start position:0% +is defined the longer + + + align:start position:0% +is defined the longer +the angular momentum is defined as a + + align:start position:0% +the angular momentum is defined as a + + + align:start position:0% +the angular momentum is defined as a +cross product is momentum + + align:start position:0% +cross product is momentum + + + align:start position:0% +cross product is momentum +so this is a nice choice of coordinate + + align:start position:0% +so this is a nice choice of coordinate + + + align:start position:0% +so this is a nice choice of coordinate +system or of + + align:start position:0% +system or of + + + align:start position:0% +system or of +axis namely that the choice of the + + align:start position:0% +axis namely that the choice of the + + + align:start position:0% +axis namely that the choice of the +momentum of the particle + + align:start position:0% +momentum of the particle + + + align:start position:0% +momentum of the particle +so you find that the total momentum + + align:start position:0% +so you find that the total momentum + + + align:start position:0% +so you find that the total momentum +perpendicular + + align:start position:0% +perpendicular + + + align:start position:0% +perpendicular +is the spin of the particle + + align:start position:0% +is the spin of the particle + + + align:start position:0% +is the spin of the particle +perpendicular + + align:start position:0% +perpendicular + + + align:start position:0% +perpendicular +and the transverse component is the + + align:start position:0% +and the transverse component is the + + + align:start position:0% +and the transverse component is the +angular momentum the orbital energy + + align:start position:0% +angular momentum the orbital energy + + + align:start position:0% +angular momentum the orbital energy +momentum and the spin of the particle in + + align:start position:0% +momentum and the spin of the particle in + + + align:start position:0% +momentum and the spin of the particle in +transverse + + align:start position:0% +transverse + + + align:start position:0% +transverse +direction this then immediately gets us + + align:start position:0% +direction this then immediately gets us + + + align:start position:0% +direction this then immediately gets us +to a new definition + + align:start position:0% +to a new definition + + + align:start position:0% +to a new definition +that of helicity you can define the + + align:start position:0% +that of helicity you can define the + + + align:start position:0% +that of helicity you can define the +helicity of a particle + + align:start position:0% +helicity of a particle + + + align:start position:0% +helicity of a particle +as a spin of the particle dotted + + align:start position:0% +as a spin of the particle dotted + + + align:start position:0% +as a spin of the particle dotted +with the momentum of the particle and + + align:start position:0% +with the momentum of the particle and + + + align:start position:0% +with the momentum of the particle and +then normalized by the momentum + + align:start position:0% +then normalized by the momentum + + + align:start position:0% +then normalized by the momentum +so you basically um for a fermion + + align:start position:0% +so you basically um for a fermion + + + align:start position:0% +so you basically um for a fermion +which has a spin one half get on plus + + align:start position:0% +which has a spin one half get on plus + + + align:start position:0% +which has a spin one half get on plus +one half + + align:start position:0% +one half + + + align:start position:0% +one half +if the spin points in the momentum + + align:start position:0% +if the spin points in the momentum + + + align:start position:0% +if the spin points in the momentum +direction + + align:start position:0% +direction + + + align:start position:0% +direction +and minus one half if it points in the + + align:start position:0% +and minus one half if it points in the + + + align:start position:0% +and minus one half if it points in the +opposite direction + + align:start position:0% +opposite direction + + + align:start position:0% +opposite direction +so now if you go back to our particle + + align:start position:0% +so now if you go back to our particle + + + align:start position:0% +so now if you go back to our particle +here + + align:start position:0% +here + + + align:start position:0% +here +of pi zero decaying into an + + align:start position:0% +of pi zero decaying into an + + + align:start position:0% +of pi zero decaying into an +electron and a positron + + align:start position:0% + + + + align:start position:0% + +um spins a one half but you find that an + + align:start position:0% +um spins a one half but you find that an + + + align:start position:0% +um spins a one half but you find that an +electron + + align:start position:0% +electron + + + align:start position:0% +electron +is a left-handed particle so its + + align:start position:0% +is a left-handed particle so its + + + align:start position:0% +is a left-handed particle so its +helicity will point in this direction + + align:start position:0% +helicity will point in this direction + + + align:start position:0% +helicity will point in this direction +and + + align:start position:0% +and + + + align:start position:0% +and +for the positron sorry for the positron + + align:start position:0% +for the positron sorry for the positron + + + align:start position:0% +for the positron sorry for the positron +it bounces interaction + + align:start position:0% +it bounces interaction + + + align:start position:0% +it bounces interaction +so the pion here is spin zero + + align:start position:0% +so the pion here is spin zero + + + align:start position:0% +so the pion here is spin zero +um and you know if you discuss this in + + align:start position:0% +um and you know if you discuss this in + + + align:start position:0% +um and you know if you discuss this in +the restroom of the pion + + align:start position:0% +the restroom of the pion + + + align:start position:0% +the restroom of the pion +the electron and the positon fly off in + + align:start position:0% +the electron and the positon fly off in + + + align:start position:0% +the electron and the positon fly off in +opposite direction + + align:start position:0% +opposite direction + + + align:start position:0% +opposite direction +and which means that the spin doesn't + + align:start position:0% +and which means that the spin doesn't + + + align:start position:0% +and which means that the spin doesn't +it's well it doesn't align to zero so + + align:start position:0% +it's well it doesn't align to zero so + + + align:start position:0% +it's well it doesn't align to zero so +that's why this is highly suppressed + + align:start position:0% +that's why this is highly suppressed + + + align:start position:0% +that's why this is highly suppressed +um it's not zero um because you can find + + align:start position:0% +um it's not zero um because you can find + + + align:start position:0% +um it's not zero um because you can find +you can put step into rest frame where + + align:start position:0% +you can put step into rest frame where + + + align:start position:0% +you can put step into rest frame where +you're just basically looking + + align:start position:0% +you're just basically looking + + + align:start position:0% +you're just basically looking +both particles from one side that was + + align:start position:0% +both particles from one side that was + + + align:start position:0% +both particles from one side that was +coming to you + + align:start position:0% +coming to you + + + align:start position:0% +coming to you +and in that case it's allowed but the + + align:start position:0% +and in that case it's allowed but the + + + align:start position:0% +and in that case it's allowed but the +spin configuration is highly surprising \ No newline at end of file diff --git a/LV3l9yqJwio.txt b/LV3l9yqJwio.txt new file mode 100644 index 0000000000000000000000000000000000000000..42b102b0dc92b76de375eedf433b27a3d568862e --- /dev/null +++ b/LV3l9yqJwio.txt @@ -0,0 +1,10315 @@ +align:start position:0% + +we + + align:start position:0% +we + + + align:start position:0% +we +uh we left off last wednesday + + align:start position:0% +uh we left off last wednesday + + + align:start position:0% +uh we left off last wednesday +last week wednesday so it's been a while + + align:start position:0% +last week wednesday so it's been a while + + + align:start position:0% +last week wednesday so it's been a while +so i wanted just to pick up + + align:start position:0% +so i wanted just to pick up + + + align:start position:0% +so i wanted just to pick up +where we left off and then cover some + + align:start position:0% +where we left off and then cover some + + + align:start position:0% +where we left off and then cover some +new things + + align:start position:0% +new things + + + align:start position:0% +new things +um today um + + align:start position:0% +um today um + + + align:start position:0% +um today um +but where we left off was with this + + align:start position:0% +but where we left off was with this + + + align:start position:0% +but where we left off was with this +diagram okay + + align:start position:0% +diagram okay + + + align:start position:0% +diagram okay +and um and i kind of you know i kind of + + align:start position:0% +and um and i kind of you know i kind of + + + align:start position:0% +and um and i kind of you know i kind of +went through it and i went through it so + + align:start position:0% +went through it and i went through it so + + + align:start position:0% +went through it and i went through it so +quickly but i want to make sure you + + align:start position:0% +quickly but i want to make sure you + + + align:start position:0% +quickly but i want to make sure you +understand it + + align:start position:0% +understand it + + + align:start position:0% +understand it +very well because this is such an + + align:start position:0% +very well because this is such an + + + align:start position:0% +very well because this is such an +important kind of diagram + + align:start position:0% +important kind of diagram + + + align:start position:0% +important kind of diagram +and we'll see it again and you may see + + align:start position:0% +and we'll see it again and you may see + + + align:start position:0% +and we'll see it again and you may see +it again in other classes this is a + + align:start position:0% +it again in other classes this is a + + + align:start position:0% +it again in other classes this is a +diagram of attraction + + align:start position:0% +diagram of attraction + + + align:start position:0% +diagram of attraction +and repulsion coming together in a + + align:start position:0% +and repulsion coming together in a + + + align:start position:0% +and repulsion coming together in a +balance + + align:start position:0% +balance + + + align:start position:0% +balance +to form a bond so so you know last + + align:start position:0% +to form a bond so so you know last + + + align:start position:0% +to form a bond so so you know last +wednesday just to remind you we made our + + align:start position:0% +wednesday just to remind you we made our + + + align:start position:0% +wednesday just to remind you we made our +first + + align:start position:0% +first + + + align:start position:0% +first +bond right we made the ionic bond + + align:start position:0% +bond right we made the ionic bond + + + align:start position:0% +bond right we made the ionic bond +and and i showed you how that worked + + align:start position:0% +and and i showed you how that worked + + + align:start position:0% +and and i showed you how that worked +because in this case the attraction + + align:start position:0% +because in this case the attraction + + + align:start position:0% +because in this case the attraction +the force of attraction is the coulomb + + align:start position:0% +the force of attraction is the coulomb + + + align:start position:0% +the force of attraction is the coulomb +potential + + align:start position:0% +potential + + + align:start position:0% +potential +right remember that goes as minus a + + align:start position:0% +right remember that goes as minus a + + + align:start position:0% +right remember that goes as minus a +constant + + align:start position:0% +constant + + + align:start position:0% +constant +times uh just write it down because why + + align:start position:0% +times uh just write it down because why + + + align:start position:0% +times uh just write it down because why +not + + align:start position:0% +not + + + align:start position:0% +not +you're using it in your goody bag right + + align:start position:0% +you're using it in your goody bag right + + + align:start position:0% +you're using it in your goody bag right +so the coulomb energy here + + align:start position:0% +so the coulomb energy here + + + align:start position:0% +so the coulomb energy here +goes as minus some constant + + align:start position:0% +goes as minus some constant + + + align:start position:0% +goes as minus some constant +times the charges the two charges + + align:start position:0% +times the charges the two charges + + + align:start position:0% +times the charges the two charges +divided by the distance between those + + align:start position:0% +divided by the distance between those + + + align:start position:0% +divided by the distance between those +charges + + align:start position:0% +charges + + + align:start position:0% +charges +that's an energy it's an energy of + + align:start position:0% +that's an energy it's an energy of + + + align:start position:0% +that's an energy it's an energy of +attraction but you know + + align:start position:0% +attraction but you know + + + align:start position:0% +attraction but you know +so here's the thing though right so if + + align:start position:0% +so here's the thing though right so if + + + align:start position:0% +so here's the thing though right so if +you have a plus and a minus charge those + + align:start position:0% +you have a plus and a minus charge those + + + align:start position:0% +you have a plus and a minus charge those +are each one + + align:start position:0% +are each one + + + align:start position:0% +are each one +right charge of electron um and then the + + align:start position:0% +right charge of electron um and then the + + + align:start position:0% +right charge of electron um and then the +distance between them when it's really + + align:start position:0% +distance between them when it's really + + + align:start position:0% +distance between them when it's really +far + + align:start position:0% +far + + + align:start position:0% +far +this this energy is pretty weak so + + align:start position:0% +this this energy is pretty weak so + + + align:start position:0% +this this energy is pretty weak so +that's this green curve here but as it + + align:start position:0% +that's this green curve here but as it + + + align:start position:0% +that's this green curve here but as it +gets closer and closer + + align:start position:0% +gets closer and closer + + + align:start position:0% +gets closer and closer +that energy gets lower and lower and + + align:start position:0% +that energy gets lower and lower and + + + align:start position:0% +that energy gets lower and lower and +remember + + align:start position:0% +remember + + + align:start position:0% +remember +happiness is lower energy right these + + align:start position:0% +happiness is lower energy right these + + + align:start position:0% +happiness is lower energy right these +atoms want to find their happy place + + align:start position:0% +atoms want to find their happy place + + + align:start position:0% +atoms want to find their happy place +and they see each other like well we can + + align:start position:0% +and they see each other like well we can + + + align:start position:0% +and they see each other like well we can +be happier if we're closer + + align:start position:0% +be happier if we're closer + + + align:start position:0% +be happier if we're closer +until a certain thing happens which is + + align:start position:0% +until a certain thing happens which is + + + align:start position:0% +until a certain thing happens which is +then + + align:start position:0% +then + + + align:start position:0% +then +they've got similar charges like the + + align:start position:0% +they've got similar charges like the + + + align:start position:0% +they've got similar charges like the +electron shells + + align:start position:0% +electron shells + + + align:start position:0% +electron shells +negative charge negative charge shelf + + align:start position:0% +negative charge negative charge shelf + + + align:start position:0% +negative charge negative charge shelf +kind of coming too close + + align:start position:0% +kind of coming too close + + + align:start position:0% +kind of coming too close +that's the the forces of repulsion + + align:start position:0% +that's the the forces of repulsion + + + align:start position:0% +that's the the forces of repulsion +and so that nets in a total energy curve + + align:start position:0% +and so that nets in a total energy curve + + + align:start position:0% +and so that nets in a total energy curve +which is this + + align:start position:0% +which is this + + + align:start position:0% +which is this +this white line here the green and the + + align:start position:0% +this white line here the green and the + + + align:start position:0% +this white line here the green and the +red then you got the the white line + + align:start position:0% +red then you got the the white line + + + align:start position:0% +red then you got the the white line +there + + align:start position:0% +there + + + align:start position:0% +there +which is the total energy because if + + align:start position:0% +which is the total energy because if + + + align:start position:0% +which is the total energy because if +they came too close then + + align:start position:0% +they came too close then + + + align:start position:0% +they came too close then +you're going to be on this thing and + + align:start position:0% +you're going to be on this thing and + + + align:start position:0% +you're going to be on this thing and +you're just going to be you know all + + align:start position:0% +you're just going to be you know all + + + align:start position:0% +you're just going to be you know all +those electrons are going to be + + align:start position:0% +those electrons are going to be + + + align:start position:0% +those electrons are going to be +overlapping each other + + align:start position:0% +overlapping each other + + + align:start position:0% +overlapping each other +and very unhappy right + + align:start position:0% +and very unhappy right + + + align:start position:0% +and very unhappy right +so this is what we do and and we said + + align:start position:0% +so this is what we do and and we said + + + align:start position:0% +so this is what we do and and we said +okay this is the bond + + align:start position:0% +okay this is the bond + + + align:start position:0% +okay this is the bond +of an atom and another atom an ion + + align:start position:0% +of an atom and another atom an ion + + + align:start position:0% +of an atom and another atom an ion +and another ion a cation and an anion + + align:start position:0% +and another ion a cation and an anion + + + align:start position:0% +and another ion a cation and an anion +we did all this wednesday i'm just + + align:start position:0% +we did all this wednesday i'm just + + + align:start position:0% +we did all this wednesday i'm just +getting us back in the mood + + align:start position:0% +getting us back in the mood + + + align:start position:0% +getting us back in the mood +right and what i told you is that that + + align:start position:0% +right and what i told you is that that + + + align:start position:0% +right and what i told you is that that +bond energy + + align:start position:0% +bond energy + + + align:start position:0% +bond energy +is related to the lattice energy right i + + align:start position:0% +is related to the lattice energy right i + + + align:start position:0% +is related to the lattice energy right i +mean now technically + + align:start position:0% +mean now technically + + + align:start position:0% +mean now technically +the lattice energy is + + align:start position:0% +the lattice energy is + + + align:start position:0% +the lattice energy is +and this is something you're playing + + align:start position:0% +and this is something you're playing + + + align:start position:0% +and this is something you're playing +around with the lattice energy + + align:start position:0% +around with the lattice energy + + + align:start position:0% +around with the lattice energy +would be the energy that it takes to go + + align:start position:0% +would be the energy that it takes to go + + + align:start position:0% +would be the energy that it takes to go +from + + align:start position:0% +from + + + align:start position:0% +from +those ions sodium plus in the gas phase + + align:start position:0% +those ions sodium plus in the gas phase + + + align:start position:0% +those ions sodium plus in the gas phase +right we put that little guy there now + + align:start position:0% +right we put that little guy there now + + + align:start position:0% +right we put that little guy there now +that is something that's going to keep + + align:start position:0% +that is something that's going to keep + + + align:start position:0% +that is something that's going to keep +coming too it's a notation i've been + + align:start position:0% +coming too it's a notation i've been + + + align:start position:0% +coming too it's a notation i've been +sneaking in + + align:start position:0% +sneaking in + + + align:start position:0% +sneaking in +gas phase right plus chlorine + + align:start position:0% +gas phase right plus chlorine + + + align:start position:0% +gas phase right plus chlorine +ion gas phase and they came together + + align:start position:0% +ion gas phase and they came together + + + align:start position:0% +ion gas phase and they came together +to make nacl + + align:start position:0% + + + + align:start position:0% + +ran out of room solid but i put it + + align:start position:0% +ran out of room solid but i put it + + + align:start position:0% +ran out of room solid but i put it +underneath + + align:start position:0% +underneath + + + align:start position:0% +underneath +solid sodium that's salt now the lattice + + align:start position:0% +solid sodium that's salt now the lattice + + + align:start position:0% +solid sodium that's salt now the lattice +energy + + align:start position:0% +energy + + + align:start position:0% +energy +is the energy that it takes to go from + + align:start position:0% +is the energy that it takes to go from + + + align:start position:0% +is the energy that it takes to go from +these ions to the solid and + + align:start position:0% +these ions to the solid and + + + align:start position:0% +these ions to the solid and +as you can see well here i just did two + + align:start position:0% +as you can see well here i just did two + + + align:start position:0% +as you can see well here i just did two +ions + + align:start position:0% +ions + + + align:start position:0% +ions +but the lattice energy is going to be + + align:start position:0% +but the lattice energy is going to be + + + align:start position:0% +but the lattice energy is going to be +related to that bond energy + + align:start position:0% +related to that bond energy + + + align:start position:0% +related to that bond energy +right okay so the lattice energy of the + + align:start position:0% +right okay so the lattice energy of the + + + align:start position:0% +right okay so the lattice energy of the +solid that you make + + align:start position:0% +solid that you make + + + align:start position:0% +solid that you make +is going to be and ionic solids there's + + align:start position:0% +is going to be and ionic solids there's + + + align:start position:0% +is going to be and ionic solids there's +a whole bunch of + + align:start position:0% +a whole bunch of + + + align:start position:0% +a whole bunch of +materials that form solids this way + + align:start position:0% +materials that form solids this way + + + align:start position:0% +materials that form solids this way +they're ionic solids they have + + align:start position:0% +they're ionic solids they have + + + align:start position:0% +they're ionic solids they have +properties + + align:start position:0% +properties + + + align:start position:0% +properties +that are general they're not always + + align:start position:0% +that are general they're not always + + + align:start position:0% +that are general they're not always +they're not always these properties but + + align:start position:0% +they're not always these properties but + + + align:start position:0% +they're not always these properties but +for the most part these are the + + align:start position:0% +for the most part these are the + + + align:start position:0% +for the most part these are the +properties of ionic solids right they + + align:start position:0% +properties of ionic solids right they + + + align:start position:0% +properties of ionic solids right they +tend to be + + align:start position:0% +tend to be + + + align:start position:0% +tend to be +solid at room temperature they tend to + + align:start position:0% +solid at room temperature they tend to + + + align:start position:0% +solid at room temperature they tend to +have high + + align:start position:0% +have high + + + align:start position:0% +have high +melting and boiling points they're often + + align:start position:0% +melting and boiling points they're often + + + align:start position:0% +melting and boiling points they're often +transparent and the visible they can + + align:start position:0% +transparent and the visible they can + + + align:start position:0% +transparent and the visible they can +they're mostly electrical insulators + + align:start position:0% +they're mostly electrical insulators + + + align:start position:0% +they're mostly electrical insulators +they're hard and brittle + + align:start position:0% +they're hard and brittle + + + align:start position:0% +they're hard and brittle +soluble in water but you're seeing + + align:start position:0% +soluble in water but you're seeing + + + align:start position:0% +soluble in water but you're seeing +in your goodie bag you're saying that's + + align:start position:0% +in your goodie bag you're saying that's + + + align:start position:0% +in your goodie bag you're saying that's +not always true because + + align:start position:0% +not always true because + + + align:start position:0% +not always true because +sometimes most of the time there but if + + align:start position:0% +sometimes most of the time there but if + + + align:start position:0% +sometimes most of the time there but if +this lattice energy is too high + + align:start position:0% +this lattice energy is too high + + + align:start position:0% +this lattice energy is too high +right then it may not even dissolve it + + align:start position:0% +right then it may not even dissolve it + + + align:start position:0% +right then it may not even dissolve it +may still be an eye but + + align:start position:0% +may still be an eye but + + + align:start position:0% +may still be an eye but +this may be some really really strong + + align:start position:0% +this may be some really really strong + + + align:start position:0% +this may be some really really strong +ionic solid right but these are the + + align:start position:0% +ionic solid right but these are the + + + align:start position:0% +ionic solid right but these are the +general properties + + align:start position:0% +general properties + + + align:start position:0% +general properties +of ionic solids okay we'll come back as + + align:start position:0% +of ionic solids okay we'll come back as + + + align:start position:0% +of ionic solids okay we'll come back as +we learn about other solids + + align:start position:0% +we learn about other solids + + + align:start position:0% +we learn about other solids +wednesday um to + + align:start position:0% +wednesday um to + + + align:start position:0% +wednesday um to +the differences in properties between + + align:start position:0% +the differences in properties between + + + align:start position:0% +the differences in properties between +different types of solids + + align:start position:0% +different types of solids + + + align:start position:0% +different types of solids +okay so that's where we ended now we've + + align:start position:0% +okay so that's where we ended now we've + + + align:start position:0% +okay so that's where we ended now we've +got we've + + align:start position:0% +got we've + + + align:start position:0% +got we've +now to do this to get to here + + align:start position:0% +now to do this to get to here + + + align:start position:0% +now to do this to get to here +we had to make ions and so we've been + + align:start position:0% +we had to make ions and so we've been + + + align:start position:0% +we had to make ions and so we've been +talking about ions and we're going to + + align:start position:0% +talking about ions and we're going to + + + align:start position:0% +talking about ions and we're going to +keep talking about ions because + + align:start position:0% +keep talking about ions because + + + align:start position:0% +keep talking about ions because +that's a very important part of how + + align:start position:0% +that's a very important part of how + + + align:start position:0% +that's a very important part of how +atoms see each other + + align:start position:0% +atoms see each other + + + align:start position:0% +atoms see each other +right am i seeing you as a neutral atom + + align:start position:0% +right am i seeing you as a neutral atom + + + align:start position:0% +right am i seeing you as a neutral atom +with all your electrons in your shell or + + align:start position:0% +with all your electrons in your shell or + + + align:start position:0% +with all your electrons in your shell or +am i seeing you with a charge uh missing + + align:start position:0% +am i seeing you with a charge uh missing + + + align:start position:0% +am i seeing you with a charge uh missing +or not that makes a big difference + + align:start position:0% +or not that makes a big difference + + + align:start position:0% +or not that makes a big difference +right in how they approach each other + + align:start position:0% +right in how they approach each other + + + align:start position:0% +right in how they approach each other +and therefore how they bond + + align:start position:0% +and therefore how they bond + + + align:start position:0% +and therefore how they bond +right which is a critical part of of + + align:start position:0% +right which is a critical part of of + + + align:start position:0% +right which is a critical part of of +what we need to learn this semester + + align:start position:0% +what we need to learn this semester + + + align:start position:0% +what we need to learn this semester +and so you know we showed this which is + + align:start position:0% +and so you know we showed this which is + + + align:start position:0% +and so you know we showed this which is +you know + + align:start position:0% +you know + + + align:start position:0% +you know +sometimes atoms actually don't mind + + align:start position:0% +sometimes atoms actually don't mind + + + align:start position:0% +sometimes atoms actually don't mind +losing + + align:start position:0% +losing + + + align:start position:0% +losing +an electron right don't mind don't mind + + align:start position:0% +an electron right don't mind don't mind + + + align:start position:0% +an electron right don't mind don't mind +is like happiness level which has to do + + align:start position:0% +is like happiness level which has to do + + + align:start position:0% +is like happiness level which has to do +with energy + + align:start position:0% +with energy + + + align:start position:0% +with energy +and so if we want to look at this more + + align:start position:0% +and so if we want to look at this more + + + align:start position:0% +and so if we want to look at this more +formally we would look at for example + + align:start position:0% +formally we would look at for example + + + align:start position:0% +formally we would look at for example +this chart from april which is the first + + align:start position:0% +this chart from april which is the first + + + align:start position:0% +this chart from april which is the first +ionization energy right now that's + + align:start position:0% +ionization energy right now that's + + + align:start position:0% +ionization energy right now that's +exactly that's something that we talked + + align:start position:0% +exactly that's something that we talked + + + align:start position:0% +exactly that's something that we talked +about + + align:start position:0% +about + + + align:start position:0% +about +right so the first ionization energy + + align:start position:0% +right so the first ionization energy + + + align:start position:0% +right so the first ionization energy +which is how much energy it takes to + + align:start position:0% +which is how much energy it takes to + + + align:start position:0% +which is how much energy it takes to +remove + + align:start position:0% +remove + + + align:start position:0% +remove +an electron from the outer shell the + + align:start position:0% +an electron from the outer shell the + + + align:start position:0% +an electron from the outer shell the +most outer shell electron the first + + align:start position:0% +most outer shell electron the first + + + align:start position:0% +most outer shell electron the first +one you would take away that's the first + + align:start position:0% +one you would take away that's the first + + + align:start position:0% +one you would take away that's the first +ionization energy + + align:start position:0% +ionization energy + + + align:start position:0% +ionization energy +all right and we saw uh again + + align:start position:0% + + + + align:start position:0% + +getting us back in the mood oh i've got + + align:start position:0% +getting us back in the mood oh i've got + + + align:start position:0% +getting us back in the mood oh i've got +colors there look so if you started for + + align:start position:0% +colors there look so if you started for + + + align:start position:0% +colors there look so if you started for +example let's start let's just take a + + align:start position:0% +example let's start let's just take a + + + align:start position:0% +example let's start let's just take a +look at this + + align:start position:0% +look at this + + + align:start position:0% +look at this +okay so here here we are at lithium + + align:start position:0% +okay so here here we are at lithium + + + align:start position:0% +okay so here here we are at lithium +i'm going to start here and that's first + + align:start position:0% +i'm going to start here and that's first + + + align:start position:0% +i'm going to start here and that's first +ionization energy and this is just the + + align:start position:0% +ionization energy and this is just the + + + align:start position:0% +ionization energy and this is just the +atomic number + + align:start position:0% +atomic number + + + align:start position:0% +atomic number +so there's lithium and remember we + + align:start position:0% +so there's lithium and remember we + + + align:start position:0% +so there's lithium and remember we +looked at this last week + + align:start position:0% +looked at this last week + + + align:start position:0% +looked at this last week +lithium and beryllium okay so if you + + align:start position:0% +lithium and beryllium okay so if you + + + align:start position:0% +lithium and beryllium okay so if you +look at that we say + + align:start position:0% +look at that we say + + + align:start position:0% +look at that we say +okay so for lithium you had three + + align:start position:0% +okay so for lithium you had three + + + align:start position:0% +okay so for lithium you had three +electrons + + align:start position:0% +electrons + + + align:start position:0% +electrons +in the core so there's lithium right and + + align:start position:0% +in the core so there's lithium right and + + + align:start position:0% +in the core so there's lithium right and +there's + + align:start position:0% +there's + + + align:start position:0% +there's +the lithium oh this is so fun because + + align:start position:0% +the lithium oh this is so fun because + + + align:start position:0% +the lithium oh this is so fun because +now we know what to call this + + align:start position:0% +now we know what to call this + + + align:start position:0% +now we know what to call this +1s2 right and then we have another shell + + align:start position:0% +1s2 right and then we have another shell + + + align:start position:0% +1s2 right and then we have another shell +these are just pictor the electron is + + align:start position:0% +these are just pictor the electron is + + + align:start position:0% +these are just pictor the electron is +not in an orbit + + align:start position:0% +not in an orbit + + + align:start position:0% +not in an orbit +it's in an orbital it's not + + align:start position:0% +it's in an orbital it's not + + + align:start position:0% +it's in an orbital it's not +moving around like this that's our + + align:start position:0% +moving around like this that's our + + + align:start position:0% +moving around like this that's our +classical mines + + align:start position:0% +classical mines + + + align:start position:0% +classical mines +fighting and it's got one more electron + + align:start position:0% +fighting and it's got one more electron + + + align:start position:0% +fighting and it's got one more electron +why did i draw a dash it's got one more + + align:start position:0% +why did i draw a dash it's got one more + + + align:start position:0% +why did i draw a dash it's got one more +electron there in the 2s + + align:start position:0% +electron there in the 2s + + + align:start position:0% +electron there in the 2s +shell and that's lithium okay but now + + align:start position:0% +shell and that's lithium okay but now + + + align:start position:0% +shell and that's lithium okay but now +we're going to go from lithium to + + align:start position:0% +we're going to go from lithium to + + + align:start position:0% +we're going to go from lithium to +beryllium and and we talked about + + align:start position:0% +beryllium and and we talked about + + + align:start position:0% +beryllium and and we talked about +so beryllium now is going to add okay + + align:start position:0% +so beryllium now is going to add okay + + + align:start position:0% +so beryllium now is going to add okay +it's going to add a + + align:start position:0% +it's going to add a + + + align:start position:0% +it's going to add a +another proton it's got all of them but + + align:start position:0% +another proton it's got all of them but + + + align:start position:0% +another proton it's got all of them but +i'm showing the one that was added + + align:start position:0% +i'm showing the one that was added + + + align:start position:0% +i'm showing the one that was added +and it's also going to add an electron + + align:start position:0% +and it's also going to add an electron + + + align:start position:0% +and it's also going to add an electron +here + + align:start position:0% +here + + + align:start position:0% +here +but see for beryllium this + + align:start position:0% +but see for beryllium this + + + align:start position:0% +but see for beryllium this +this electron is not + + align:start position:0% +this electron is not + + + align:start position:0% +this electron is not +really not shielded anymore not shielded + + align:start position:0% +really not shielded anymore not shielded + + + align:start position:0% +really not shielded anymore not shielded +more for the most part + + align:start position:0% +more for the most part + + + align:start position:0% +more for the most part +you know it went into the same shell the + + align:start position:0% +you know it went into the same shell the + + + align:start position:0% +you know it went into the same shell the +same + + align:start position:0% +same + + + align:start position:0% +same +you know the same n right and the same l + + align:start position:0% +you know the same n right and the same l + + + align:start position:0% +you know the same n right and the same l +same shape same quantum number so it's + + align:start position:0% +same shape same quantum number so it's + + + align:start position:0% +same shape same quantum number so it's +there's nothing else shielding and yet + + align:start position:0% +there's nothing else shielding and yet + + + align:start position:0% +there's nothing else shielding and yet +there's a whole other proton + + align:start position:0% +there's a whole other proton + + + align:start position:0% +there's a whole other proton +and that's why beryllium is smaller + + align:start position:0% +and that's why beryllium is smaller + + + align:start position:0% +and that's why beryllium is smaller +this is all stuff we talked about + + align:start position:0% +this is all stuff we talked about + + + align:start position:0% +this is all stuff we talked about +wednesday but see look that's + + align:start position:0% +wednesday but see look that's + + + align:start position:0% +wednesday but see look that's +also why it's harder to pull + + align:start position:0% +also why it's harder to pull + + + align:start position:0% +also why it's harder to pull +the outer electron off of beryllium + + align:start position:0% +the outer electron off of beryllium + + + align:start position:0% +the outer electron off of beryllium +there it is than lithium + + align:start position:0% +there it is than lithium + + + align:start position:0% +there it is than lithium +so those really go together right the + + align:start position:0% +so those really go together right the + + + align:start position:0% +so those really go together right the +rate all the radius stuff we talked + + align:start position:0% +rate all the radius stuff we talked + + + align:start position:0% +rate all the radius stuff we talked +about + + align:start position:0% +about + + + align:start position:0% +about +holds you know that same kind of logic + + align:start position:0% +holds you know that same kind of logic + + + align:start position:0% +holds you know that same kind of logic +in terms of how these electrons are with + + align:start position:0% +in terms of how these electrons are with + + + align:start position:0% +in terms of how these electrons are with +respect to their nucleus + + align:start position:0% +respect to their nucleus + + + align:start position:0% +respect to their nucleus +holds for ionization energy now + + align:start position:0% +holds for ionization energy now + + + align:start position:0% +holds for ionization energy now +let's add let's go to boron + + align:start position:0% +let's add let's go to boron + + + align:start position:0% +let's add let's go to boron +so if we go to boron now + + align:start position:0% +so if we go to boron now + + + align:start position:0% +so if we go to boron now +we're going over look at what happened + + align:start position:0% +we're going over look at what happened + + + align:start position:0% +we're going over look at what happened +look at that we went from there to there + + align:start position:0% +look at that we went from there to there + + + align:start position:0% +look at that we went from there to there +and the ionization energy got lower + + align:start position:0% +and the ionization energy got lower + + + align:start position:0% +and the ionization energy got lower +well that's also something we can + + align:start position:0% +well that's also something we can + + + align:start position:0% +well that's also something we can +understand because now + + align:start position:0% +understand because now + + + align:start position:0% +understand because now +we're putting it into the 2p + + align:start position:0% +we're putting it into the 2p + + + align:start position:0% +we're putting it into the 2p +okay so so if i do that it would be + + align:start position:0% +okay so so if i do that it would be + + + align:start position:0% +okay so so if i do that it would be +i'm going to put it under here 2s2 + + align:start position:0% +i'm going to put it under here 2s2 + + + align:start position:0% +i'm going to put it under here 2s2 +right and now if i go to boron + + align:start position:0% +right and now if i go to boron + + + align:start position:0% +right and now if i go to boron +i'm going to put it here in a 2p shell + + align:start position:0% +i'm going to put it here in a 2p shell + + + align:start position:0% +i'm going to put it here in a 2p shell +so i'm starting + + align:start position:0% +so i'm starting + + + align:start position:0% +so i'm starting +a new l now remember + + align:start position:0% +a new l now remember + + + align:start position:0% +a new l now remember +that means the shape the quantum number + + align:start position:0% +that means the shape the quantum number + + + align:start position:0% +that means the shape the quantum number +is still two but the shape of the + + align:start position:0% +is still two but the shape of the + + + align:start position:0% +is still two but the shape of the +orbital is different + + align:start position:0% +orbital is different + + + align:start position:0% +orbital is different +and now we know also from something we + + align:start position:0% +and now we know also from something we + + + align:start position:0% +and now we know also from something we +learned last week + + align:start position:0% +learned last week + + + align:start position:0% +learned last week +that because of orbital penetration the + + align:start position:0% +that because of orbital penetration the + + + align:start position:0% +that because of orbital penetration the +energies of the 2p and 2s orbitals are + + align:start position:0% +energies of the 2p and 2s orbitals are + + + align:start position:0% +energies of the 2p and 2s orbitals are +not the same + + align:start position:0% +not the same + + + align:start position:0% +not the same +right the s energies are a little lower + + align:start position:0% +right the s energies are a little lower + + + align:start position:0% +right the s energies are a little lower +and it's get it lets those electrons get + + align:start position:0% +and it's get it lets those electrons get + + + align:start position:0% +and it's get it lets those electrons get +a little bit closer to that positive + + align:start position:0% +a little bit closer to that positive + + + align:start position:0% +a little bit closer to that positive +charge that they want so badly + + align:start position:0% +charge that they want so badly + + + align:start position:0% +charge that they want so badly +so we know that this is going to be a + + align:start position:0% +so we know that this is going to be a + + + align:start position:0% +so we know that this is going to be a +little further out + + align:start position:0% +little further out + + + align:start position:0% +little further out +and so there's a little bit of shielding + + align:start position:0% +and so there's a little bit of shielding + + + align:start position:0% +and so there's a little bit of shielding +little + + align:start position:0% +little + + + align:start position:0% +little +shielding that you get for this + + align:start position:0% +shielding that you get for this + + + align:start position:0% +shielding that you get for this +plus orbital penetration that we talked + + align:start position:0% +plus orbital penetration that we talked + + + align:start position:0% +plus orbital penetration that we talked +about + + align:start position:0% +about + + + align:start position:0% +about +and that puts it further out + + align:start position:0% +and that puts it further out + + + align:start position:0% +and that puts it further out +right and therefore the attraction is a + + align:start position:0% +right and therefore the attraction is a + + + align:start position:0% +right and therefore the attraction is a +little less and therefore + + align:start position:0% +little less and therefore + + + align:start position:0% +little less and therefore +the ionization energy went down yeah and + + align:start position:0% +the ionization energy went down yeah and + + + align:start position:0% +the ionization energy went down yeah and +now we're going to fill those up but + + align:start position:0% +now we're going to fill those up but + + + align:start position:0% +now we're going to fill those up but +it's the same thing as before now you're + + align:start position:0% +it's the same thing as before now you're + + + align:start position:0% +it's the same thing as before now you're +not going further out you're just adding + + align:start position:0% +not going further out you're just adding + + + align:start position:0% +not going further out you're just adding +and you're not really screening while + + align:start position:0% +and you're not really screening while + + + align:start position:0% +and you're not really screening while +you add right + + align:start position:0% +you add right + + + align:start position:0% +you add right +and so you're adding electrons into this + + align:start position:0% +and so you're adding electrons into this + + + align:start position:0% +and so you're adding electrons into this +2p orbital but you're also adding all + + align:start position:0% +2p orbital but you're also adding all + + + align:start position:0% +2p orbital but you're also adding all +this positive charge + + align:start position:0% +this positive charge + + + align:start position:0% +this positive charge +salute and and so the ionization energy + + align:start position:0% +salute and and so the ionization energy + + + align:start position:0% +salute and and so the ionization energy +is going to go up + + align:start position:0% +is going to go up + + + align:start position:0% +is going to go up +except look at that oh half filling + + align:start position:0% +except look at that oh half filling + + + align:start position:0% +except look at that oh half filling +right there half filling a little extra + + align:start position:0% +right there half filling a little extra + + + align:start position:0% +right there half filling a little extra +stability remember we talked about + + align:start position:0% +stability remember we talked about + + + align:start position:0% +stability remember we talked about +exceptions right half filling + + align:start position:0% +exceptions right half filling + + + align:start position:0% +exceptions right half filling +half filling and so you see now you can + + align:start position:0% +half filling and so you see now you can + + + align:start position:0% +half filling and so you see now you can +see we can understand these trends that + + align:start position:0% +see we can understand these trends that + + + align:start position:0% +see we can understand these trends that +were being measured + + align:start position:0% +were being measured + + + align:start position:0% +were being measured +right at the time these ionization + + align:start position:0% +right at the time these ionization + + + align:start position:0% +right at the time these ionization +potentials but now we really can + + align:start position:0% +potentials but now we really can + + + align:start position:0% +potentials but now we really can +understand them + + align:start position:0% +understand them + + + align:start position:0% +understand them +and you can group them and you can see + + align:start position:0% +and you can group them and you can see + + + align:start position:0% +and you can group them and you can see +if you group them + + align:start position:0% +if you group them + + + align:start position:0% +if you group them +remember we also grouped the periodic + + align:start position:0% +remember we also grouped the periodic + + + align:start position:0% +remember we also grouped the periodic +table a little bit by electron filling + + align:start position:0% +table a little bit by electron filling + + + align:start position:0% +table a little bit by electron filling +quantum numbers right you had the s and + + align:start position:0% +quantum numbers right you had the s and + + + align:start position:0% +quantum numbers right you had the s and +p blocks + + align:start position:0% +p blocks + + + align:start position:0% +p blocks +those are also often called the main + + align:start position:0% +those are also often called the main + + + align:start position:0% +those are also often called the main +group elements they're + + align:start position:0% +group elements they're + + + align:start position:0% +group elements they're +in the first couple of rows of those + + align:start position:0% +in the first couple of rows of those + + + align:start position:0% +in the first couple of rows of those +they're the the most abundant elements + + align:start position:0% +they're the the most abundant elements + + + align:start position:0% +they're the the most abundant elements +right um and and so those are and those + + align:start position:0% +right um and and so those are and those + + + align:start position:0% +right um and and so those are and those +tr but those trends now you fully + + align:start position:0% +tr but those trends now you fully + + + align:start position:0% +tr but those trends now you fully +understand from + + align:start position:0% +understand from + + + align:start position:0% +understand from +the the quantum mechanical solution to + + align:start position:0% +the the quantum mechanical solution to + + + align:start position:0% +the the quantum mechanical solution to +the atom + + align:start position:0% +the atom + + + align:start position:0% +the atom +right and the electron filling of those + + align:start position:0% +right and the electron filling of those + + + align:start position:0% +right and the electron filling of those +orbitals we can actually really + + align:start position:0% +orbitals we can actually really + + + align:start position:0% +orbitals we can actually really +understand it all right + + align:start position:0% +understand it all right + + + align:start position:0% +understand it all right +and so that's the and then the same + + align:start position:0% +and so that's the and then the same + + + align:start position:0% +and so that's the and then the same +thing happens with the d + + align:start position:0% +thing happens with the d + + + align:start position:0% +thing happens with the d +it's a little more complicated by the + + align:start position:0% +it's a little more complicated by the + + + align:start position:0% +it's a little more complicated by the +way these are often called transition + + align:start position:0% +way these are often called transition + + + align:start position:0% +way these are often called transition +metals + + align:start position:0% +metals + + + align:start position:0% +metals +the d block i told you about the d block + + align:start position:0% +the d block i told you about the d block + + + align:start position:0% +the d block i told you about the d block +last week they're also called transition + + align:start position:0% +last week they're also called transition + + + align:start position:0% +last week they're also called transition +metals + + align:start position:0% +metals + + + align:start position:0% +metals +and the word metal is something we'll + + align:start position:0% +and the word metal is something we'll + + + align:start position:0% +and the word metal is something we'll +talk a lot about in a few weeks when we + + align:start position:0% +talk a lot about in a few weeks when we + + + align:start position:0% +talk a lot about in a few weeks when we +make metals + + align:start position:0% +make metals + + + align:start position:0% +make metals +but they're called transitions because + + align:start position:0% +but they're called transitions because + + + align:start position:0% +but they're called transitions because +literally they transition + + align:start position:0% +literally they transition + + + align:start position:0% +literally they transition +in the filling they transition they you + + align:start position:0% +in the filling they transition they you + + + align:start position:0% +in the filling they transition they you +you're filling d + + align:start position:0% +you're filling d + + + align:start position:0% +you're filling d +orbitals right transition you're kind of + + align:start position:0% +orbitals right transition you're kind of + + + align:start position:0% +orbitals right transition you're kind of +and that makes it a little more complex + + align:start position:0% +and that makes it a little more complex + + + align:start position:0% +and that makes it a little more complex +in terms of what happens + + align:start position:0% +in terms of what happens + + + align:start position:0% +in terms of what happens +but the same trends hold the same trends + + align:start position:0% +but the same trends hold the same trends + + + align:start position:0% +but the same trends hold the same trends +hold you see + + align:start position:0% +hold you see + + + align:start position:0% +hold you see +you as you add more d electrons the + + align:start position:0% +you as you add more d electrons the + + + align:start position:0% +you as you add more d electrons the +ionization energy keeps going up okay + + align:start position:0% +ionization energy keeps going up okay + + + align:start position:0% +ionization energy keeps going up okay +now this is extremely important this + + align:start position:0% +now this is extremely important this + + + align:start position:0% +now this is extremely important this +ionization energy + + align:start position:0% +ionization energy + + + align:start position:0% +ionization energy +the first ionization energy is very + + align:start position:0% +the first ionization energy is very + + + align:start position:0% +the first ionization energy is very +important because it tells you so much + + align:start position:0% +important because it tells you so much + + + align:start position:0% +important because it tells you so much +about + + align:start position:0% +about + + + align:start position:0% +about +you know the outer electron whether an + + align:start position:0% +you know the outer electron whether an + + + align:start position:0% +you know the outer electron whether an +atom is going to be an anion or a cation + + align:start position:0% +atom is going to be an anion or a cation + + + align:start position:0% +atom is going to be an anion or a cation +but all of the ionization you could you + + align:start position:0% +but all of the ionization you could you + + + align:start position:0% +but all of the ionization you could you +could throw a whole lot of energy at + + align:start position:0% +could throw a whole lot of energy at + + + align:start position:0% +could throw a whole lot of energy at +these atoms + + align:start position:0% +these atoms + + + align:start position:0% +these atoms +and they'll all come off right and and + + align:start position:0% +and they'll all come off right and and + + + align:start position:0% +and they'll all come off right and and +so you know + + align:start position:0% +so you know + + + align:start position:0% +so you know +so we we played with this kind of energy + + align:start position:0% +so we we played with this kind of energy + + + align:start position:0% +so we we played with this kind of energy +this is visible light you had your goody + + align:start position:0% +this is visible light you had your goody + + + align:start position:0% +this is visible light you had your goody +bag too + + align:start position:0% +bag too + + + align:start position:0% +bag too +you got a spectrometer you can see lines + + align:start position:0% +you got a spectrometer you can see lines + + + align:start position:0% +you got a spectrometer you can see lines +in here this is a continuous spectrum + + align:start position:0% +in here this is a continuous spectrum + + + align:start position:0% +in here this is a continuous spectrum +but you see you got this whole all these + + align:start position:0% +but you see you got this whole all these + + + align:start position:0% +but you see you got this whole all these +different wavelengths + + align:start position:0% +different wavelengths + + + align:start position:0% +different wavelengths +right and and they have and now you see + + align:start position:0% +right and and they have and now you see + + + align:start position:0% +right and and they have and now you see +this and you don't just think about + + align:start position:0% +this and you don't just think about + + + align:start position:0% +this and you don't just think about +colors + + align:start position:0% +colors + + + align:start position:0% +colors +you think about energies right and and + + align:start position:0% +you think about energies right and and + + + align:start position:0% +you think about energies right and and +so if you think + + align:start position:0% +so if you think + + + align:start position:0% +so if you think +that way because i want to know how can + + align:start position:0% +that way because i want to know how can + + + align:start position:0% +that way because i want to know how can +i measure + + align:start position:0% +i measure + + + align:start position:0% +i measure +how can i measure these things ah stop + + align:start position:0% +how can i measure these things ah stop + + + align:start position:0% +how can i measure these things ah stop +better all right and so if i you know + + align:start position:0% +better all right and so if i you know + + + align:start position:0% +better all right and so if i you know +if i look at energies oh + + align:start position:0% +if i look at energies oh + + + align:start position:0% +if i look at energies oh +enter energies i've got like the visible + + align:start position:0% +enter energies i've got like the visible + + + align:start position:0% +enter energies i've got like the visible +right which is around oh i don't know + + align:start position:0% +right which is around oh i don't know + + + align:start position:0% +right which is around oh i don't know +say 2 to 6 ev + + align:start position:0% +say 2 to 6 ev + + + align:start position:0% +say 2 to 6 ev +that's pretty high energy and then + + align:start position:0% +that's pretty high energy and then + + + align:start position:0% +that's pretty high energy and then +you've got well now + + align:start position:0% +you've got well now + + + align:start position:0% +you've got well now +can i shine visible light and and kick + + align:start position:0% +can i shine visible light and and kick + + + align:start position:0% +can i shine visible light and and kick +out + + align:start position:0% +out + + + align:start position:0% +out +you know a lithium electron well the + + align:start position:0% +you know a lithium electron well the + + + align:start position:0% +you know a lithium electron well the +answer is + + align:start position:0% +answer is + + + align:start position:0% +answer is +roughly yes if it's if it's you know the + + align:start position:0% +roughly yes if it's if it's you know the + + + align:start position:0% +roughly yes if it's if it's you know the +lithium energy ionization + + align:start position:0% +lithium energy ionization + + + align:start position:0% +lithium energy ionization +oh let's just go back and look that + + align:start position:0% +oh let's just go back and look that + + + align:start position:0% +oh let's just go back and look that +first ionization energy + + align:start position:0% +first ionization energy + + + align:start position:0% +first ionization energy +520 kilojoules per mole i know that's + + align:start position:0% +520 kilojoules per mole i know that's + + + align:start position:0% +520 kilojoules per mole i know that's +5.4 + + align:start position:0% +5.4 + + + align:start position:0% +5.4 +ev ish because i don't mind going back + + align:start position:0% +ev ish because i don't mind going back + + + align:start position:0% +ev ish because i don't mind going back +and forth + + align:start position:0% +and forth + + + align:start position:0% +and forth +right kilojoules per mole of electrons + + align:start position:0% +right kilojoules per mole of electrons + + + align:start position:0% +right kilojoules per mole of electrons +joules ev + + align:start position:0% +joules ev + + + align:start position:0% +joules ev +moles you can go back and forth but + + align:start position:0% +moles you can go back and forth but + + + align:start position:0% +moles you can go back and forth but +that's right around here + + align:start position:0% +that's right around here + + + align:start position:0% +that's right around here +so i could shine visible light and + + align:start position:0% +so i could shine visible light and + + + align:start position:0% +so i could shine visible light and +potentially knock that out but see + + align:start position:0% +potentially knock that out but see + + + align:start position:0% +potentially knock that out but see +if i wanted the 1s electron of lithium + + align:start position:0% +if i wanted the 1s electron of lithium + + + align:start position:0% +if i wanted the 1s electron of lithium +well that's it's much much lower in + + align:start position:0% +well that's it's much much lower in + + + align:start position:0% +well that's it's much much lower in +energy because remember we talk about + + align:start position:0% +energy because remember we talk about + + + align:start position:0% +energy because remember we talk about +it goes in and in each time i add charge + + align:start position:0% +it goes in and in each time i add charge + + + align:start position:0% +it goes in and in each time i add charge +and so it would take 122 electron volts + + align:start position:0% +and so it would take 122 electron volts + + + align:start position:0% +and so it would take 122 electron volts +to knock that out + + align:start position:0% +to knock that out + + + align:start position:0% +to knock that out +right and so but we have that kind of + + align:start position:0% +right and so but we have that kind of + + + align:start position:0% +right and so but we have that kind of +light + + align:start position:0% +light + + + align:start position:0% +light +right the uv the uv would be something + + align:start position:0% +right the uv the uv would be something + + + align:start position:0% +right the uv the uv would be something +like + + align:start position:0% +like + + + align:start position:0% +like +oh 10 to 100 and then if we really want + + align:start position:0% +oh 10 to 100 and then if we really want + + + align:start position:0% +oh 10 to 100 and then if we really want +to blast these we could go + + align:start position:0% +to blast these we could go + + + align:start position:0% +to blast these we could go +x-rays are we going to have fun with + + align:start position:0% +x-rays are we going to have fun with + + + align:start position:0% +x-rays are we going to have fun with +x-rays + + align:start position:0% +x-rays + + + align:start position:0% +x-rays +later in the semester and this would go + + align:start position:0% +later in the semester and this would go + + + align:start position:0% +later in the semester and this would go +to something like a hundred thousand + + align:start position:0% +to something like a hundred thousand + + + align:start position:0% +to something like a hundred thousand +and so i got it you know if i wanted to + + align:start position:0% +and so i got it you know if i wanted to + + + align:start position:0% +and so i got it you know if i wanted to +i could shine light + + align:start position:0% +i could shine light + + + align:start position:0% +i could shine light +and ionize the whole thing and that is + + align:start position:0% +and ionize the whole thing and that is + + + align:start position:0% +and ionize the whole thing and that is +in fact + + align:start position:0% +in fact + + + align:start position:0% +in fact +one of the single most important + + align:start position:0% +one of the single most important + + + align:start position:0% +one of the single most important +experiments we do to characterize + + align:start position:0% +experiments we do to characterize + + + align:start position:0% +experiments we do to characterize +materials and so i want you to know + + align:start position:0% +materials and so i want you to know + + + align:start position:0% +materials and so i want you to know +about it + + align:start position:0% +about it + + + align:start position:0% +about it +it's called photoelectron spectroscopy + + align:start position:0% +it's called photoelectron spectroscopy + + + align:start position:0% +it's called photoelectron spectroscopy +photo + + align:start position:0% +photo + + + align:start position:0% +photo +electron + + align:start position:0% + + + + align:start position:0% + +spectroscopy + + align:start position:0% + + + + align:start position:0% + +and for short we will not + + align:start position:0% +and for short we will not + + + align:start position:0% +and for short we will not +write that out ever again i will write + + align:start position:0% +write that out ever again i will write + + + align:start position:0% +write that out ever again i will write +out pes + + align:start position:0% +out pes + + + align:start position:0% +out pes +photoelectron spectroscopy now this is a + + align:start position:0% +photoelectron spectroscopy now this is a + + + align:start position:0% +photoelectron spectroscopy now this is a +characterization + + align:start position:0% +characterization + + + align:start position:0% +characterization +tool i'm basically saying well what you + + align:start position:0% +tool i'm basically saying well what you + + + align:start position:0% +tool i'm basically saying well what you +know i need energy i'm going to get it + + align:start position:0% +know i need energy i'm going to get it + + + align:start position:0% +know i need energy i'm going to get it +from + + align:start position:0% +from + + + align:start position:0% +from +some photon source but i'm going to get + + align:start position:0% +some photon source but i'm going to get + + + align:start position:0% +some photon source but i'm going to get +enough to just blast all the electrons + + align:start position:0% +enough to just blast all the electrons + + + align:start position:0% +enough to just blast all the electrons +out of this material out of this atom + + align:start position:0% +out of this material out of this atom + + + align:start position:0% +out of this material out of this atom +because for now our material they're + + align:start position:0% +because for now our material they're + + + align:start position:0% +because for now our material they're +just atoms and i want to know about + + align:start position:0% +just atoms and i want to know about + + + align:start position:0% +just atoms and i want to know about +these atoms + + align:start position:0% +these atoms + + + align:start position:0% +these atoms +okay so let's take a look so what + + align:start position:0% +okay so let's take a look so what + + + align:start position:0% +okay so let's take a look so what +happens when i do this well + + align:start position:0% +happens when i do this well + + + align:start position:0% +happens when i do this well +let's see first of all i've got some + + align:start position:0% +let's see first of all i've got some + + + align:start position:0% +let's see first of all i've got some +energy + + align:start position:0% +energy + + + align:start position:0% +energy +that we know is h new it's dependent on + + align:start position:0% +that we know is h new it's dependent on + + + align:start position:0% +that we know is h new it's dependent on +the frequency + + align:start position:0% +the frequency + + + align:start position:0% +the frequency +there are the frequencies they're the no + + align:start position:0% +there are the frequencies they're the no + + + align:start position:0% +there are the frequencies they're the no +they're there + + align:start position:0% +they're there + + + align:start position:0% +they're there +okay and so now i've got some adam + + align:start position:0% +okay and so now i've got some adam + + + align:start position:0% +okay and so now i've got some adam +here and what do i do well i look + + align:start position:0% +here and what do i do well i look + + + align:start position:0% +here and what do i do well i look +does anything happen no what about now i + + align:start position:0% +does anything happen no what about now i + + + align:start position:0% +does anything happen no what about now i +don't know + + align:start position:0% +don't know + + + align:start position:0% +don't know +okay what about now oh all of a sudden + + align:start position:0% +okay what about now oh all of a sudden + + + align:start position:0% +okay what about now oh all of a sudden +they come flying + + align:start position:0% +they come flying + + + align:start position:0% +they come flying +out electrons right + + align:start position:0% +out electrons right + + + align:start position:0% +out electrons right +and i measure their energy + + align:start position:0% +and i measure their energy + + + align:start position:0% +and i measure their energy +it kind of it goes right back to the + + align:start position:0% +it kind of it goes right back to the + + + align:start position:0% +it kind of it goes right back to the +photoelectric effect right that einstein + + align:start position:0% +photoelectric effect right that einstein + + + align:start position:0% +photoelectric effect right that einstein +was doing he was shining visible-ish + + align:start position:0% +was doing he was shining visible-ish + + + align:start position:0% +was doing he was shining visible-ish +light + + align:start position:0% +light + + + align:start position:0% +light +onto metals and seeing one electro but + + align:start position:0% +onto metals and seeing one electro but + + + align:start position:0% +onto metals and seeing one electro but +now i'm shining all sorts of light + + align:start position:0% +now i'm shining all sorts of light + + + align:start position:0% +now i'm shining all sorts of light +onto an atom and i want them all to come + + align:start position:0% +onto an atom and i want them all to come + + + align:start position:0% +onto an atom and i want them all to come +out not just the outer one + + align:start position:0% +out not just the outer one + + + align:start position:0% +out not just the outer one +and so well you can see if i measure + + align:start position:0% +and so well you can see if i measure + + + align:start position:0% +and so well you can see if i measure +so now i'm going to measure + + align:start position:0% + + + + align:start position:0% + +the kinetic energy of these and + + align:start position:0% +the kinetic energy of these and + + + align:start position:0% +the kinetic energy of these and +the ionization energy of that electron + + align:start position:0% +the ionization energy of that electron + + + align:start position:0% +the ionization energy of that electron +is going to equal + + align:start position:0% +is going to equal + + + align:start position:0% +is going to equal +how whatever the energy of the incident + + align:start position:0% +how whatever the energy of the incident + + + align:start position:0% +how whatever the energy of the incident +photon was + + align:start position:0% +photon was + + + align:start position:0% +photon was +minus the kinetic energy of the electron + + align:start position:0% +minus the kinetic energy of the electron + + + align:start position:0% +minus the kinetic energy of the electron +right that's what i want i want that + + align:start position:0% +right that's what i want i want that + + + align:start position:0% +right that's what i want i want that +ionization energy + + align:start position:0% +ionization energy + + + align:start position:0% +ionization energy +this is just to be clear ionization + + align:start position:0% +this is just to be clear ionization + + + align:start position:0% +this is just to be clear ionization +energy and like i said i want it all + + align:start position:0% +energy and like i said i want it all + + + align:start position:0% +energy and like i said i want it all +not just the first i want the second the + + align:start position:0% +not just the first i want the second the + + + align:start position:0% +not just the first i want the second the +third so now you see how so this is the + + align:start position:0% +third so now you see how so this is the + + + align:start position:0% +third so now you see how so this is the +experiment that you do what are the + + align:start position:0% +experiment that you do what are the + + + align:start position:0% +experiment that you do what are the +results + + align:start position:0% +results + + + align:start position:0% +results +well the results are really just what + + align:start position:0% +well the results are really just what + + + align:start position:0% +well the results are really just what +we've been doing but you turn it over + + align:start position:0% +we've been doing but you turn it over + + + align:start position:0% +we've been doing but you turn it over +so let's look at hydrogen okay now what + + align:start position:0% +so let's look at hydrogen okay now what + + + align:start position:0% +so let's look at hydrogen okay now what +have we been doing what do i mean by + + align:start position:0% +have we been doing what do i mean by + + + align:start position:0% +have we been doing what do i mean by +that what we've been doing is we've been + + align:start position:0% +that what we've been doing is we've been + + + align:start position:0% +that what we've been doing is we've been +going like this + + align:start position:0% +going like this + + + align:start position:0% +going like this +what's that okay this is hydrogen 1s1 i + + align:start position:0% +what's that okay this is hydrogen 1s1 i + + + align:start position:0% +what's that okay this is hydrogen 1s1 i +could do that or i could just label it + + align:start position:0% +could do that or i could just label it + + + align:start position:0% +could do that or i could just label it +the 1s and then you see the one electron + + align:start position:0% +the 1s and then you see the one electron + + + align:start position:0% +the 1s and then you see the one electron +right there + + align:start position:0% +right there + + + align:start position:0% +right there +now if i if i shine light on this + + align:start position:0% +now if i if i shine light on this + + + align:start position:0% +now if i if i shine light on this +and i measure the way that you do a pes + + align:start position:0% +and i measure the way that you do a pes + + + align:start position:0% +and i measure the way that you do a pes +for hydrogen is you would look at the + + align:start position:0% +for hydrogen is you would look at the + + + align:start position:0% +for hydrogen is you would look at the +ionization energy + + align:start position:0% +ionization energy + + + align:start position:0% +ionization energy +on the x-axis and this would be the + + align:start position:0% +on the x-axis and this would be the + + + align:start position:0% +on the x-axis and this would be the +relative + + align:start position:0% +relative + + + align:start position:0% +relative +electron count on the y-axis so you're + + align:start position:0% +electron count on the y-axis so you're + + + align:start position:0% +electron count on the y-axis so you're +just counting + + align:start position:0% +just counting + + + align:start position:0% +just counting +right and what you would see in hydrogen + + align:start position:0% +right and what you would see in hydrogen + + + align:start position:0% +right and what you would see in hydrogen +is there'd be a peak + + align:start position:0% +is there'd be a peak + + + align:start position:0% +is there'd be a peak +it'd look like this that's it + + align:start position:0% +it'd look like this that's it + + + align:start position:0% +it'd look like this that's it +if all the electrons in hydrogen one + + align:start position:0% +if all the electrons in hydrogen one + + + align:start position:0% +if all the electrons in hydrogen one +are in their ground state 1s then you + + align:start position:0% +are in their ground state 1s then you + + + align:start position:0% +are in their ground state 1s then you +would see a peak and this would be + + align:start position:0% +would see a peak and this would be + + + align:start position:0% +would see a peak and this would be +you know that it would be at minus 13.6 + + align:start position:0% +you know that it would be at minus 13.6 + + + align:start position:0% +you know that it would be at minus 13.6 +right that would be the energy that it + + align:start position:0% +right that would be the energy that it + + + align:start position:0% +right that would be the energy that it +takes to ionize it + + align:start position:0% +takes to ionize it + + + align:start position:0% +takes to ionize it +and and this would be the 1s uh peak + + align:start position:0% +and and this would be the 1s uh peak + + + align:start position:0% +and and this would be the 1s uh peak +and that's what you measure now it gets + + align:start position:0% +and that's what you measure now it gets + + + align:start position:0% +and that's what you measure now it gets +more fun because now + + align:start position:0% +more fun because now + + + align:start position:0% +more fun because now +i can also look at other elements so + + align:start position:0% +i can also look at other elements so + + + align:start position:0% +i can also look at other elements so +let's draw helium + + align:start position:0% +let's draw helium + + + align:start position:0% +let's draw helium +underneath it i'm going to try to + + align:start position:0% +underneath it i'm going to try to + + + align:start position:0% +underneath it i'm going to try to +squeeze it in + + align:start position:0% +squeeze it in + + + align:start position:0% +squeeze it in +if i look at helium well helium is also + + align:start position:0% +if i look at helium well helium is also + + + align:start position:0% +if i look at helium well helium is also +1s and its pes + + align:start position:0% +1s and its pes + + + align:start position:0% +1s and its pes +would be so this is now + + align:start position:0% +would be so this is now + + + align:start position:0% +would be so this is now +ionization energy this is the pes plot + + align:start position:0% +ionization energy this is the pes plot + + + align:start position:0% +ionization energy this is the pes plot +and the pes for helium would be also + + align:start position:0% +and the pes for helium would be also + + + align:start position:0% +and the pes for helium would be also +the 1s but the relative counts + + align:start position:0% +the 1s but the relative counts + + + align:start position:0% +the 1s but the relative counts +would be twice as high so the peak of + + align:start position:0% +would be twice as high so the peak of + + + align:start position:0% +would be twice as high so the peak of +helium would be twice as high + + align:start position:0% +helium would be twice as high + + + align:start position:0% +helium would be twice as high +as the peak of hydrogen because you know + + align:start position:0% +as the peak of hydrogen because you know + + + align:start position:0% +as the peak of hydrogen because you know +for the same + + align:start position:0% +for the same + + + align:start position:0% +for the same +number of photons in i'm getting that + + align:start position:0% +number of photons in i'm getting that + + + align:start position:0% +number of photons in i'm getting that +many more i've got both these electrons + + align:start position:0% +many more i've got both these electrons + + + align:start position:0% +many more i've got both these electrons +coming out + + align:start position:0% +coming out + + + align:start position:0% +coming out +right so the relative peaks + + align:start position:0% +right so the relative peaks + + + align:start position:0% +right so the relative peaks +the relative peaks i got two more that + + align:start position:0% +the relative peaks i got two more that + + + align:start position:0% +the relative peaks i got two more that +can come out + + align:start position:0% +can come out + + + align:start position:0% +can come out +right so this p now if i go to okay now + + align:start position:0% +right so this p now if i go to okay now + + + align:start position:0% +right so this p now if i go to okay now +it gets really interesting because now + + align:start position:0% +it gets really interesting because now + + + align:start position:0% +it gets really interesting because now +i'm oh + + align:start position:0% +i'm oh + + + align:start position:0% +i'm oh +i even have room which is making me very + + align:start position:0% +i even have room which is making me very + + + align:start position:0% +i even have room which is making me very +happy + + align:start position:0% +happy + + + align:start position:0% +happy +because now i can do lithium right here + + align:start position:0% +because now i can do lithium right here + + + align:start position:0% +because now i can do lithium right here +and if you look at lithium + + align:start position:0% +and if you look at lithium + + + align:start position:0% +and if you look at lithium +lithium goes like this + + align:start position:0% +lithium goes like this + + + align:start position:0% +lithium goes like this +right and if i look at a pes + + align:start position:0% +right and if i look at a pes + + + align:start position:0% +right and if i look at a pes +plot of lithium the ionization energy + + align:start position:0% +plot of lithium the ionization energy + + + align:start position:0% +plot of lithium the ionization energy +and the relative + + align:start position:0% +and the relative + + + align:start position:0% +and the relative +electron count okay i'm going to have + + align:start position:0% +electron count okay i'm going to have + + + align:start position:0% +electron count okay i'm going to have +those 1s electrons filled + + align:start position:0% +those 1s electrons filled + + + align:start position:0% +those 1s electrons filled +and there's going to be another energy + + align:start position:0% +and there's going to be another energy + + + align:start position:0% +and there's going to be another energy +where the 2s electrons are so this is + + align:start position:0% +where the 2s electrons are so this is + + + align:start position:0% +where the 2s electrons are so this is +energy here + + align:start position:0% +energy here + + + align:start position:0% +energy here +these are the orbitals and then + + align:start position:0% +these are the orbitals and then + + + align:start position:0% +these are the orbitals and then +somewhere over here is going to be + + align:start position:0% +somewhere over here is going to be + + + align:start position:0% +somewhere over here is going to be +a peak that's exactly half as high + + align:start position:0% +a peak that's exactly half as high + + + align:start position:0% +a peak that's exactly half as high +exactly i mean that makes a lot of sense + + align:start position:0% +exactly i mean that makes a lot of sense + + + align:start position:0% +exactly i mean that makes a lot of sense +because there's half as + + align:start position:0% +because there's half as + + + align:start position:0% +because there's half as +right there's twice as many electrons + + align:start position:0% +right there's twice as many electrons + + + align:start position:0% +right there's twice as many electrons +it's the relative electron count in the + + align:start position:0% +it's the relative electron count in the + + + align:start position:0% +it's the relative electron count in the +atom + + align:start position:0% +atom + + + align:start position:0% +atom +there's twice as many electrons coming + + align:start position:0% +there's twice as many electrons coming + + + align:start position:0% +there's twice as many electrons coming +out of that + + align:start position:0% +out of that + + + align:start position:0% +out of that +1s orbital in the 2s so i'm going to get + + align:start position:0% +1s orbital in the 2s so i'm going to get + + + align:start position:0% +1s orbital in the 2s so i'm going to get +a half as high peak here + + align:start position:0% +a half as high peak here + + + align:start position:0% +a half as high peak here +right and and usually now this i just + + align:start position:0% +right and and usually now this i just + + + align:start position:0% +right and and usually now this i just +told you + + align:start position:0% +told you + + + align:start position:0% +told you +the lithium atom this electron is 5 + + align:start position:0% +the lithium atom this electron is 5 + + + align:start position:0% +the lithium atom this electron is 5 +point something four ish electron volts + + align:start position:0% +point something four ish electron volts + + + align:start position:0% +point something four ish electron volts +to remove + + align:start position:0% +to remove + + + align:start position:0% +to remove +this is 122. so literally for lithium + + align:start position:0% +this is 122. so literally for lithium + + + align:start position:0% +this is 122. so literally for lithium +this would be 122. this would be 5.4 + + align:start position:0% +this would be 122. this would be 5.4 + + + align:start position:0% +this would be 122. this would be 5.4 +and you know it's ionization energy and + + align:start position:0% +and you know it's ionization energy and + + + align:start position:0% +and you know it's ionization energy and +ev + + align:start position:0% +ev + + + align:start position:0% +ev +and what you would do is you would draw + + align:start position:0% +and what you would do is you would draw + + + align:start position:0% +and what you would do is you would draw +the axis like that so you don't have to + + align:start position:0% +the axis like that so you don't have to + + + align:start position:0% +the axis like that so you don't have to +put this all the way over here + + align:start position:0% +put this all the way over here + + + align:start position:0% +put this all the way over here +right so we often what and all this + + align:start position:0% +right so we often what and all this + + + align:start position:0% +right so we often what and all this +means is i've broken up + + align:start position:0% +means is i've broken up + + + align:start position:0% +means is i've broken up +you know the the axis and it's + + align:start position:0% +you know the the axis and it's + + + align:start position:0% +you know the the axis and it's +continuing to count here + + align:start position:0% +continuing to count here + + + align:start position:0% +continuing to count here +in a different scale right + + align:start position:0% +in a different scale right + + + align:start position:0% +in a different scale right +these pes plots are absolutely essential + + align:start position:0% +these pes plots are absolutely essential + + + align:start position:0% +these pes plots are absolutely essential +in understanding uh atoms + + align:start position:0% +in understanding uh atoms + + + align:start position:0% +in understanding uh atoms +and materials because look at what you + + align:start position:0% +and materials because look at what you + + + align:start position:0% +and materials because look at what you +get you get + + align:start position:0% +get you get + + + align:start position:0% +get you get +literally the electron filling plot + + align:start position:0% +literally the electron filling plot + + + align:start position:0% +literally the electron filling plot +turned over + + align:start position:0% +turned over + + + align:start position:0% +turned over +it's incredible you get it turned over + + align:start position:0% + + + + align:start position:0% + +and you can write this as oh let's just + + align:start position:0% +and you can write this as oh let's just + + + align:start position:0% +and you can write this as oh let's just +do this story you know + + align:start position:0% +do this story you know + + + align:start position:0% +do this story you know +i could write this as 1s2 we have so + + align:start position:0% +i could write this as 1s2 we have so + + + align:start position:0% +i could write this as 1s2 we have so +many options now 2s1 + + align:start position:0% +many options now 2s1 + + + align:start position:0% +many options now 2s1 +right i could write this as + + align:start position:0% +right i could write this as + + + align:start position:0% +right i could write this as +helium 2s1 that would be like using the + + align:start position:0% +helium 2s1 that would be like using the + + + align:start position:0% +helium 2s1 that would be like using the +noble gas + + align:start position:0% +noble gas + + + align:start position:0% +noble gas +right i could make what people you know + + align:start position:0% +right i could make what people you know + + + align:start position:0% +right i could make what people you know +there's so many + + align:start position:0% +there's so many + + + align:start position:0% +there's so many +i can make box plots oh box plots + + align:start position:0% +i can make box plots oh box plots + + + align:start position:0% +i can make box plots oh box plots +you can do this some people really like + + align:start position:0% +you can do this some people really like + + + align:start position:0% +you can do this some people really like +putting things in boxes + + align:start position:0% +putting things in boxes + + + align:start position:0% +putting things in boxes +1s 2s box plots + + align:start position:0% + + + + align:start position:0% + +right so this is all meaning these + + align:start position:0% +right so this is all meaning these + + + align:start position:0% +right so this is all meaning these +all say the same thing + + align:start position:0% +all say the same thing + + + align:start position:0% +all say the same thing +lithium they all say lithium + + align:start position:0% + + + + align:start position:0% + +right photoelectron spectra so i could + + align:start position:0% +right photoelectron spectra so i could + + + align:start position:0% +right photoelectron spectra so i could +ask you questions like this + + align:start position:0% +ask you questions like this + + + align:start position:0% +ask you questions like this +there's one ionization energy megajoules + + align:start position:0% +there's one ionization energy megajoules + + + align:start position:0% +there's one ionization energy megajoules +per mole + + align:start position:0% +per mole + + + align:start position:0% +per mole +relative number of electrons this + + align:start position:0% +relative number of electrons this + + + align:start position:0% +relative number of electrons this +element has a charge of two plus and the + + align:start position:0% +element has a charge of two plus and the + + + align:start position:0% +element has a charge of two plus and the +pes shown below what is it + + align:start position:0% +pes shown below what is it + + + align:start position:0% +pes shown below what is it +i said well okay i know one s two + + align:start position:0% +i said well okay i know one s two + + + align:start position:0% +i said well okay i know one s two +two s two and since this is going up + + align:start position:0% +two s two and since this is going up + + + align:start position:0% +two s two and since this is going up +three times as high that sure looks like + + align:start position:0% +three times as high that sure looks like + + + align:start position:0% +three times as high that sure looks like +two p + + align:start position:0% +two p + + + align:start position:0% +two p +six doesn't it that looks like two 2p6 + + align:start position:0% +six doesn't it that looks like two 2p6 + + + align:start position:0% +six doesn't it that looks like two 2p6 +remember it's this turned over on its + + align:start position:0% +remember it's this turned over on its + + + align:start position:0% +remember it's this turned over on its +side right where the peak height + + align:start position:0% +side right where the peak height + + + align:start position:0% +side right where the peak height +corresponds to the filling + + align:start position:0% +corresponds to the filling + + + align:start position:0% +corresponds to the filling +that's what that experiment gives you + + align:start position:0% +that's what that experiment gives you + + + align:start position:0% +that's what that experiment gives you +2p6 well then it must + + align:start position:0% + + + + align:start position:0% + +you have your periodic table uh-huh + + align:start position:0% +you have your periodic table uh-huh + + + align:start position:0% +you have your periodic table uh-huh +because then tight + + align:start position:0% +because then tight + + + align:start position:0% +because then tight +neon it must be neon + + align:start position:0% +neon it must be neon + + + align:start position:0% +neon it must be neon +no who said no no don't just + + align:start position:0% +no who said no no don't just + + + align:start position:0% +no who said no no don't just +yes it can't be neon because of the + + align:start position:0% +yes it can't be neon because of the + + + align:start position:0% +yes it can't be neon because of the +question + + align:start position:0% +question + + + align:start position:0% +question +it's got a charge of two plus oh + + align:start position:0% +it's got a charge of two plus oh + + + align:start position:0% +it's got a charge of two plus oh +tricky tricky tricky + + align:start position:0% +tricky tricky tricky + + + align:start position:0% +tricky tricky tricky +magnesium it must be magnesium that is + + align:start position:0% +magnesium it must be magnesium that is + + + align:start position:0% +magnesium it must be magnesium that is +the pe + + align:start position:0% +the pe + + + align:start position:0% +the pe +right but it's magnesium two plus + + align:start position:0% +right but it's magnesium two plus + + + align:start position:0% +right but it's magnesium two plus +because i said it had a char + + align:start position:0% +because i said it had a char + + + align:start position:0% +because i said it had a char +thank you shout out i appreciate that + + align:start position:0% +thank you shout out i appreciate that + + + align:start position:0% +thank you shout out i appreciate that +okay so that's how that's the power of + + align:start position:0% +okay so that's how that's the power of + + + align:start position:0% +okay so that's how that's the power of +the photoelectron spectra and we'll be + + align:start position:0% +the photoelectron spectra and we'll be + + + align:start position:0% +the photoelectron spectra and we'll be +using it + + align:start position:0% +using it + + + align:start position:0% +using it +in the class and this tells us about how + + align:start position:0% +in the class and this tells us about how + + + align:start position:0% +in the class and this tells us about how +electrons + + align:start position:0% +electrons + + + align:start position:0% +electrons +leave atoms it tells us about ionization + + align:start position:0% +leave atoms it tells us about ionization + + + align:start position:0% +leave atoms it tells us about ionization +energies not just the first + + align:start position:0% +energies not just the first + + + align:start position:0% +energies not just the first +which is the one all the way out here to + + align:start position:0% +which is the one all the way out here to + + + align:start position:0% +which is the one all the way out here to +the right on the pes plot but all of + + align:start position:0% +the right on the pes plot but all of + + + align:start position:0% +the right on the pes plot but all of +them + + align:start position:0% +them + + + align:start position:0% +them +because i shine enough energy light to + + align:start position:0% +because i shine enough energy light to + + + align:start position:0% +because i shine enough energy light to +get them all out + + align:start position:0% +get them all out + + + align:start position:0% +get them all out +now you can also so that's about losing + + align:start position:0% +now you can also so that's about losing + + + align:start position:0% +now you can also so that's about losing +electrons + + align:start position:0% +electrons + + + align:start position:0% +electrons +you can also gain them and um and so + + align:start position:0% +you can also gain them and um and so + + + align:start position:0% +you can also gain them and um and so +i mentioned this um a little bit but i + + align:start position:0% +i mentioned this um a little bit but i + + + align:start position:0% +i mentioned this um a little bit but i +just for completeness i want to come + + align:start position:0% +just for completeness i want to come + + + align:start position:0% +just for completeness i want to come +back to this you have electro + + align:start position:0% +back to this you have electro + + + align:start position:0% +back to this you have electro +you have ionization energy right + + align:start position:0% +you have ionization energy right + + + align:start position:0% +you have ionization energy right +which is how much energy it takes to + + align:start position:0% +which is how much energy it takes to + + + align:start position:0% +which is how much energy it takes to +pull an electron out you also have + + align:start position:0% +pull an electron out you also have + + + align:start position:0% +pull an electron out you also have +electron affinity and because some atoms + + align:start position:0% +electron affinity and because some atoms + + + align:start position:0% +electron affinity and because some atoms +also uh might want electrons + + align:start position:0% +also uh might want electrons + + + align:start position:0% +also uh might want electrons +and so when you look at those plots it's + + align:start position:0% +and so when you look at those plots it's + + + align:start position:0% +and so when you look at those plots it's +actually all makes sense again + + align:start position:0% +actually all makes sense again + + + align:start position:0% +actually all makes sense again +look at this some atoms like chlorine + + align:start position:0% +look at this some atoms like chlorine + + + align:start position:0% +look at this some atoms like chlorine +this is electron affinity by atom number + + align:start position:0% +this is electron affinity by atom number + + + align:start position:0% +this is electron affinity by atom number +some atoms like chlorine really want + + align:start position:0% +some atoms like chlorine really want + + + align:start position:0% +some atoms like chlorine really want +another electron why + + align:start position:0% +another electron why + + + align:start position:0% +another electron why +because it's got an incomplete shell + + align:start position:0% +because it's got an incomplete shell + + + align:start position:0% +because it's got an incomplete shell +it's so it's so close it just needs one + + align:start position:0% +it's so it's so close it just needs one + + + align:start position:0% +it's so it's so close it just needs one +more electron + + align:start position:0% +more electron + + + align:start position:0% +more electron +to fill that outer shell and it wants it + + align:start position:0% +to fill that outer shell and it wants it + + + align:start position:0% +to fill that outer shell and it wants it +and that's the electron affinity is how + + align:start position:0% +and that's the electron affinity is how + + + align:start position:0% +and that's the electron affinity is how +much does it want it now + + align:start position:0% +much does it want it now + + + align:start position:0% +much does it want it now +want happiness happiness lower energy + + align:start position:0% +want happiness happiness lower energy + + + align:start position:0% +want happiness happiness lower energy +that's what this so if you're not going + + align:start position:0% +that's what this so if you're not going + + + align:start position:0% +that's what this so if you're not going +to lower your energy + + align:start position:0% +to lower your energy + + + align:start position:0% +to lower your energy +with another electron then you're just + + align:start position:0% +with another electron then you're just + + + align:start position:0% +with another electron then you're just +saying no you + + align:start position:0% +saying no you + + + align:start position:0% +saying no you +just say no zero i will not take an + + align:start position:0% +just say no zero i will not take an + + + align:start position:0% +just say no zero i will not take an +electron + + align:start position:0% +electron + + + align:start position:0% +electron +because if you give me one my energy is + + align:start position:0% +because if you give me one my energy is + + + align:start position:0% +because if you give me one my energy is +going to go up and i will be a less + + align:start position:0% +going to go up and i will be a less + + + align:start position:0% +going to go up and i will be a less +happy atom and you can make + + align:start position:0% +happy atom and you can make + + + align:start position:0% +happy atom and you can make +that makes sense too right filled shells + + align:start position:0% +that makes sense too right filled shells + + + align:start position:0% +that makes sense too right filled shells +they don't nitrogen + + align:start position:0% +they don't nitrogen + + + align:start position:0% +they don't nitrogen +nitrogen's got a a half-filled shell no + + align:start position:0% +nitrogen's got a a half-filled shell no + + + align:start position:0% +nitrogen's got a a half-filled shell no +to that electron + + align:start position:0% +to that electron + + + align:start position:0% +to that electron +i like my half-filled shell it gives me + + align:start position:0% +i like my half-filled shell it gives me + + + align:start position:0% +i like my half-filled shell it gives me +a little added stability + + align:start position:0% +a little added stability + + + align:start position:0% +a little added stability +a little extra kick if you give me that + + align:start position:0% +a little extra kick if you give me that + + + align:start position:0% +a little extra kick if you give me that +electron + + align:start position:0% +electron + + + align:start position:0% +electron +you know i'm gonna have not have that + + align:start position:0% +you know i'm gonna have not have that + + + align:start position:0% +you know i'm gonna have not have that +added stability i don't want it + + align:start position:0% +added stability i don't want it + + + align:start position:0% +added stability i don't want it +zero right zero + + align:start position:0% +zero right zero + + + align:start position:0% +zero right zero +losing electrons gaining electrons + + align:start position:0% +losing electrons gaining electrons + + + align:start position:0% +losing electrons gaining electrons +losing electrons gaining electrons + + align:start position:0% +losing electrons gaining electrons + + + align:start position:0% +losing electrons gaining electrons +why does it matter why does it matter + + align:start position:0% +why does it matter why does it matter + + + align:start position:0% +why does it matter why does it matter +well we made a solid last week today the + + align:start position:0% +well we made a solid last week today the + + + align:start position:0% +well we made a solid last week today the +answer is obvious + + align:start position:0% +answer is obvious + + + align:start position:0% +answer is obvious +it matters because of danish wind + + align:start position:0% +it matters because of danish wind + + + align:start position:0% +it matters because of danish wind +obviously 43 + + align:start position:0% +obviously 43 + + + align:start position:0% +obviously 43 +in 2014 43 of all the electrical energy + + align:start position:0% +in 2014 43 of all the electrical energy + + + align:start position:0% +in 2014 43 of all the electrical energy +in denmark came from wind + + align:start position:0% +in denmark came from wind + + + align:start position:0% +in denmark came from wind +it's higher now but see now this is a + + align:start position:0% +it's higher now but see now this is a + + + align:start position:0% +it's higher now but see now this is a +quarter of the danish wind + + align:start position:0% +quarter of the danish wind + + + align:start position:0% +quarter of the danish wind +i got i only gave you a two minute + + align:start position:0% +i got i only gave you a two minute + + + align:start position:0% +i got i only gave you a two minute +hemodialysis + + align:start position:0% +hemodialysis + + + align:start position:0% +hemodialysis +why this matters on wednesday so i'm + + align:start position:0% +why this matters on wednesday so i'm + + + align:start position:0% +why this matters on wednesday so i'm +going extended today + + align:start position:0% +going extended today + + + align:start position:0% +going extended today +just a little bit but danish wind + + align:start position:0% +just a little bit but danish wind + + + align:start position:0% +just a little bit but danish wind +people are very dependable so over a + + align:start position:0% +people are very dependable so over a + + + align:start position:0% +people are very dependable so over a +three-month period + + align:start position:0% +three-month period + + + align:start position:0% +three-month period +this is how much we need energy + + align:start position:0% +this is how much we need energy + + + align:start position:0% +this is how much we need energy +electricity + + align:start position:0% +electricity + + + align:start position:0% +electricity +but that look at the wind supply that + + align:start position:0% +but that look at the wind supply that + + + align:start position:0% +but that look at the wind supply that +but sometimes it's really there for us + + align:start position:0% +but sometimes it's really there for us + + + align:start position:0% +but sometimes it's really there for us +sometimes it's not at all there + + align:start position:0% +sometimes it's not at all there + + + align:start position:0% +sometimes it's not at all there +sometimes it's predictable sometimes + + align:start position:0% +sometimes it's predictable sometimes + + + align:start position:0% +sometimes it's predictable sometimes +it's not at all predictable + + align:start position:0% + + + + align:start position:0% + +with that much of your electricity + + align:start position:0% +with that much of your electricity + + + align:start position:0% +with that much of your electricity +coming from this type of unreliable + + align:start position:0% +coming from this type of unreliable + + + align:start position:0% +coming from this type of unreliable +resource that is a huge challenge now + + align:start position:0% +resource that is a huge challenge now + + + align:start position:0% +resource that is a huge challenge now +even if you go out to arizona + + align:start position:0% +even if you go out to arizona + + + align:start position:0% +even if you go out to arizona +and you talk about solar system + + align:start position:0% +and you talk about solar system + + + align:start position:0% +and you talk about solar system +arizona's sunny all the time no + + align:start position:0% +arizona's sunny all the time no + + + align:start position:0% +arizona's sunny all the time no +not sunny all the time most of the time + + align:start position:0% +not sunny all the time most of the time + + + align:start position:0% +not sunny all the time most of the time +more than boston + + align:start position:0% +more than boston + + + align:start position:0% +more than boston +but this is the sun in arizona that's + + align:start position:0% +but this is the sun in arizona that's + + + align:start position:0% +but this is the sun in arizona that's +the power you're getting from it + + align:start position:0% +the power you're getting from it + + + align:start position:0% +the power you're getting from it +and look at this these these are just + + align:start position:0% +and look at this these these are just + + + align:start position:0% +and look at this these these are just +clouds because arizona does have clouds + + align:start position:0% +clouds because arizona does have clouds + + + align:start position:0% +clouds because arizona does have clouds +and they passed by and they blocked the + + align:start position:0% +and they passed by and they blocked the + + + align:start position:0% +and they passed by and they blocked the +sun do you know what a nightmare this is + + align:start position:0% +sun do you know what a nightmare this is + + + align:start position:0% +sun do you know what a nightmare this is +for a grid operator + + align:start position:0% +for a grid operator + + + align:start position:0% +for a grid operator +if a lot of your customers get their + + align:start position:0% +if a lot of your customers get their + + + align:start position:0% +if a lot of your customers get their +energy + + align:start position:0% +energy + + + align:start position:0% +energy +in this way yeah and all of a sudden + + align:start position:0% +in this way yeah and all of a sudden + + + align:start position:0% +in this way yeah and all of a sudden +you know half of your supply of energy + + align:start position:0% +you know half of your supply of energy + + + align:start position:0% +you know half of your supply of energy +just turns off + + align:start position:0% +just turns off + + + align:start position:0% +just turns off +right i mean that's a huge problem right + + align:start position:0% +right i mean that's a huge problem right + + + align:start position:0% +right i mean that's a huge problem right +and this is one of the most + + align:start position:0% +and this is one of the most + + + align:start position:0% +and this is one of the most +limiting factors for increasing + + align:start position:0% +limiting factors for increasing + + + align:start position:0% +limiting factors for increasing +to a large extent the amount of + + align:start position:0% +to a large extent the amount of + + + align:start position:0% +to a large extent the amount of +renewables we have on our grid + + align:start position:0% +renewables we have on our grid + + + align:start position:0% +renewables we have on our grid +and so of course i know a lot of you are + + align:start position:0% +and so of course i know a lot of you are + + + align:start position:0% +and so of course i know a lot of you are +thinking well just store it and that's + + align:start position:0% +thinking well just store it and that's + + + align:start position:0% +thinking well just store it and that's +what we need to do + + align:start position:0% +what we need to do + + + align:start position:0% +what we need to do +right but it turns out that really one + + align:start position:0% +right but it turns out that really one + + + align:start position:0% +right but it turns out that really one +of the only ways we have to store energy + + align:start position:0% +of the only ways we have to store energy + + + align:start position:0% +of the only ways we have to store energy +at this large scale + + align:start position:0% +at this large scale + + + align:start position:0% +at this large scale +is pumped hydro and you see we're + + align:start position:0% +is pumped hydro and you see we're + + + align:start position:0% +is pumped hydro and you see we're +pumping water up up a hill + + align:start position:0% +pumping water up up a hill + + + align:start position:0% +pumping water up up a hill +when i have excess i pump water up a + + align:start position:0% +when i have excess i pump water up a + + + align:start position:0% +when i have excess i pump water up a +hill + + align:start position:0% +hill + + + align:start position:0% +hill +and then when i need i roll it back down + + align:start position:0% +and then when i need i roll it back down + + + align:start position:0% +and then when i need i roll it back down +and i turn a turbine with it right i'm + + align:start position:0% +and i turn a turbine with it right i'm + + + align:start position:0% +and i turn a turbine with it right i'm +literally just + + align:start position:0% +literally just + + + align:start position:0% +literally just +trading energy potential energy right + + align:start position:0% +trading energy potential energy right + + + align:start position:0% +trading energy potential energy right +and then i bring it back kinetic energy + + align:start position:0% +and then i bring it back kinetic energy + + + align:start position:0% +and then i bring it back kinetic energy +and then i make electricity + + align:start position:0% +and then i make electricity + + + align:start position:0% +and then i make electricity +now the problem is that pumped hydro you + + align:start position:0% +now the problem is that pumped hydro you + + + align:start position:0% +now the problem is that pumped hydro you +know pump + + align:start position:0% +know pump + + + align:start position:0% +know pump +well as you can see pumped hydra is + + align:start position:0% +well as you can see pumped hydra is + + + align:start position:0% +well as you can see pumped hydra is +going to be good where there's hydro + + align:start position:0% +going to be good where there's hydro + + + align:start position:0% +going to be good where there's hydro +where there's water + + align:start position:0% +where there's water + + + align:start position:0% +where there's water +so that's limiting but it also is a very + + align:start position:0% +so that's limiting but it also is a very + + + align:start position:0% +so that's limiting but it also is a very +low + + align:start position:0% +low + + + align:start position:0% +low +uh aerial density and there are also a + + align:start position:0% +uh aerial density and there are also a + + + align:start position:0% +uh aerial density and there are also a +lot of uh + + align:start position:0% +lot of uh + + + align:start position:0% +lot of uh +environmental challenges with making + + align:start position:0% +environmental challenges with making + + + align:start position:0% +environmental challenges with making +this work in a way that doesn't + + align:start position:0% +this work in a way that doesn't + + + align:start position:0% +this work in a way that doesn't +uh harm the environment so there are a + + align:start position:0% +uh harm the environment so there are a + + + align:start position:0% +uh harm the environment so there are a +lot of issues with scaling up pumped + + align:start position:0% +lot of issues with scaling up pumped + + + align:start position:0% +lot of issues with scaling up pumped +hydro + + align:start position:0% +hydro + + + align:start position:0% +hydro +a lot of issues as a storage and so i + + align:start position:0% +a lot of issues as a storage and so i + + + align:start position:0% +a lot of issues as a storage and so i +asked well what else can we pump up + + align:start position:0% +asked well what else can we pump up + + + align:start position:0% +asked well what else can we pump up +hills + + align:start position:0% +hills + + + align:start position:0% +hills +and we know what the answer is because + + align:start position:0% +and we know what the answer is because + + + align:start position:0% +and we know what the answer is because +it's what we're talking about + + align:start position:0% + + + + align:start position:0% + +ions where are they ions we can pump + + align:start position:0% +ions where are they ions we can pump + + + align:start position:0% +ions where are they ions we can pump +ions up hills + + align:start position:0% +ions up hills + + + align:start position:0% +ions up hills +there's my picture look at that right + + align:start position:0% +there's my picture look at that right + + + align:start position:0% +there's my picture look at that right +ions and you know what this is it's a + + align:start position:0% +ions and you know what this is it's a + + + align:start position:0% +ions and you know what this is it's a +battery + + align:start position:0% +battery + + + align:start position:0% +battery +a battery is two different materials two + + align:start position:0% +a battery is two different materials two + + + align:start position:0% +a battery is two different materials two +different metals a and b + + align:start position:0% +different metals a and b + + + align:start position:0% +different metals a and b +where one of them has an ion i don't + + align:start position:0% +where one of them has an ion i don't + + + align:start position:0% +where one of them has an ion i don't +know like lithium + + align:start position:0% +know like lithium + + + align:start position:0% +know like lithium +for example + + align:start position:0% + + + + align:start position:0% + +that can go back and forth and the + + align:start position:0% +that can go back and forth and the + + + align:start position:0% +that can go back and forth and the +electrolyte is this thing in between + + align:start position:0% +electrolyte is this thing in between + + + align:start position:0% +electrolyte is this thing in between +that only allows that ion through okay + + align:start position:0% +that only allows that ion through okay + + + align:start position:0% +that only allows that ion through okay +now here's the thing so if i'm a metal + + align:start position:0% +now here's the thing so if i'm a metal + + + align:start position:0% +now here's the thing so if i'm a metal +and i lose a positively charged atom + + align:start position:0% +and i lose a positively charged atom + + + align:start position:0% +and i lose a positively charged atom +right well then i got to stay neutral + + align:start position:0% +right well then i got to stay neutral + + + align:start position:0% +right well then i got to stay neutral +the only way to stay neutral is to pump + + align:start position:0% +the only way to stay neutral is to pump + + + align:start position:0% +the only way to stay neutral is to pump +an electron out + + align:start position:0% +an electron out + + + align:start position:0% +an electron out +right is to put on so so if i want to + + align:start position:0% +right is to put on so so if i want to + + + align:start position:0% +right is to put on so so if i want to +draw electrons out of this + + align:start position:0% +draw electrons out of this + + + align:start position:0% +draw electrons out of this +that's fine as long as i draw ions out + + align:start position:0% +that's fine as long as i draw ions out + + + align:start position:0% +that's fine as long as i draw ions out +of it and then both of them can do work + + align:start position:0% +of it and then both of them can do work + + + align:start position:0% +of it and then both of them can do work +and then they come back and they roll + + align:start position:0% +and then they come back and they roll + + + align:start position:0% +and then they come back and they roll +down + + align:start position:0% +down + + + align:start position:0% +down +an energy hill that's what they're doing + + align:start position:0% +an energy hill that's what they're doing + + + align:start position:0% +an energy hill that's what they're doing +and going back and forth shuttling + + align:start position:0% +and going back and forth shuttling + + + align:start position:0% +and going back and forth shuttling +back and forth back and forth they're + + align:start position:0% +back and forth back and forth they're + + + align:start position:0% +back and forth back and forth they're +rolling down a hill literally + + align:start position:0% +rolling down a hill literally + + + align:start position:0% +rolling down a hill literally +of energy yeah when it's in one metal + + align:start position:0% +of energy yeah when it's in one metal + + + align:start position:0% +of energy yeah when it's in one metal +it's higher in energy + + align:start position:0% +it's higher in energy + + + align:start position:0% +it's higher in energy +and then when i plug it up you know plug + + align:start position:0% +and then when i plug it up you know plug + + + align:start position:0% +and then when i plug it up you know plug +my phone in + + align:start position:0% +my phone in + + + align:start position:0% +my phone in +it rolls down that energy hill + + align:start position:0% +it rolls down that energy hill + + + align:start position:0% +it rolls down that energy hill +right and as it does it travels across + + align:start position:0% +right and as it does it travels across + + + align:start position:0% +right and as it does it travels across +to the other other metal gets lower in + + align:start position:0% +to the other other metal gets lower in + + + align:start position:0% +to the other other metal gets lower in +energy and the electrons got to come + + align:start position:0% +energy and the electrons got to come + + + align:start position:0% +energy and the electrons got to come +around and do work for me because + + align:start position:0% +around and do work for me because + + + align:start position:0% +around and do work for me because +otherwise + + align:start position:0% +otherwise + + + align:start position:0% +otherwise +it wouldn't stay neutral that's what a + + align:start position:0% +it wouldn't stay neutral that's what a + + + align:start position:0% +it wouldn't stay neutral that's what a +battery is it's all about ions + + align:start position:0% +battery is it's all about ions + + + align:start position:0% +battery is it's all about ions +right it's all about ions it's like a + + align:start position:0% +right it's all about ions it's like a + + + align:start position:0% +right it's all about ions it's like a +ski lift i like to think of it + + align:start position:0% +ski lift i like to think of it + + + align:start position:0% +ski lift i like to think of it +you know it's like these ions are + + align:start position:0% +you know it's like these ions are + + + align:start position:0% +you know it's like these ions are +getting in into a ski lift they're just + + align:start position:0% +getting in into a ski lift they're just + + + align:start position:0% +getting in into a ski lift they're just +getting + + align:start position:0% +getting + + + align:start position:0% +getting +you know up the mountain and then when + + align:start position:0% +you know up the mountain and then when + + + align:start position:0% +you know up the mountain and then when +you plug it in they're ready to ski down + + align:start position:0% +you plug it in they're ready to ski down + + + align:start position:0% +you plug it in they're ready to ski down +and they go down and that's just + + align:start position:0% +and they go down and that's just + + + align:start position:0% +and they go down and that's just +cruising across this electrolyte + + align:start position:0% +cruising across this electrolyte + + + align:start position:0% +cruising across this electrolyte +right and i don't know what the electron + + align:start position:0% +right and i don't know what the electron + + + align:start position:0% +right and i don't know what the electron +is in this analogy but that's all the + + align:start position:0% +is in this analogy but that's all the + + + align:start position:0% +is in this analogy but that's all the +battery is + + align:start position:0% +battery is + + + align:start position:0% +battery is +you plug it in and the ski lift takes it + + align:start position:0% +you plug it in and the ski lift takes it + + + align:start position:0% +you plug it in and the ski lift takes it +up + + align:start position:0% +up + + + align:start position:0% +up +right when you charge it and now you you + + align:start position:0% +right when you charge it and now you you + + + align:start position:0% +right when you charge it and now you you +power your phone on and it + + align:start position:0% +power your phone on and it + + + align:start position:0% +power your phone on and it +rolls back down well see the thing is + + align:start position:0% +rolls back down well see the thing is + + + align:start position:0% +rolls back down well see the thing is +that batteries have seen + + align:start position:0% +that batteries have seen + + + align:start position:0% +that batteries have seen +a moore's law of themselves + + align:start position:0% +a moore's law of themselves + + + align:start position:0% +a moore's law of themselves +if you look at the moore's law for + + align:start position:0% +if you look at the moore's law for + + + align:start position:0% +if you look at the moore's law for +batteries it uh + + align:start position:0% +batteries it uh + + + align:start position:0% +batteries it uh +doubles right so this is the battery + + align:start position:0% +doubles right so this is the battery + + + align:start position:0% +doubles right so this is the battery +energy storage of batteries + + align:start position:0% +energy storage of batteries + + + align:start position:0% +energy storage of batteries +over the last 150-ish years it doubles + + align:start position:0% +over the last 150-ish years it doubles + + + align:start position:0% +over the last 150-ish years it doubles +every 60 years + + align:start position:0% +every 60 years + + + align:start position:0% +every 60 years +that's not a very good more zone but + + align:start position:0% +that's not a very good more zone but + + + align:start position:0% +that's not a very good more zone but +that's completely changed + + align:start position:0% +that's completely changed + + + align:start position:0% +that's completely changed +that's completely changed recently and + + align:start position:0% +that's completely changed recently and + + + align:start position:0% +that's completely changed recently and +the reason is + + align:start position:0% +the reason is + + + align:start position:0% +the reason is +all about ion shuttling materials + + align:start position:0% +all about ion shuttling materials + + + align:start position:0% +all about ion shuttling materials +and ion storing materials this is why + + align:start position:0% +and ion storing materials this is why + + + align:start position:0% +and ion storing materials this is why +this has happened this is why we've had + + align:start position:0% +this has happened this is why we've had + + + align:start position:0% +this has happened this is why we've had +a revolution + + align:start position:0% +a revolution + + + align:start position:0% +a revolution +in electrochemical energy storage right + + align:start position:0% +in electrochemical energy storage right + + + align:start position:0% +in electrochemical energy storage right +because + + align:start position:0% +because + + + align:start position:0% +because +150 years ago we only made batteries out + + align:start position:0% +150 years ago we only made batteries out + + + align:start position:0% +150 years ago we only made batteries out +of about 10 different materials and + + align:start position:0% +of about 10 different materials and + + + align:start position:0% +of about 10 different materials and +today + + align:start position:0% +today + + + align:start position:0% +today +there's well over 80 that are + + align:start position:0% +there's well over 80 that are + + + align:start position:0% +there's well over 80 that are +commercialized + + align:start position:0% +commercialized + + + align:start position:0% +commercialized +there's many hundreds in research labs + + align:start position:0% +there's many hundreds in research labs + + + align:start position:0% +there's many hundreds in research labs +that + + align:start position:0% +that + + + align:start position:0% +that +what is making the difference is that + + align:start position:0% +what is making the difference is that + + + align:start position:0% +what is making the difference is that +those materials now + + align:start position:0% +those materials now + + + align:start position:0% +those materials now +allow the shuttling to happen it allows + + align:start position:0% +allow the shuttling to happen it allows + + + align:start position:0% +allow the shuttling to happen it allows +the shuttling to happen more easily + + align:start position:0% +the shuttling to happen more easily + + + align:start position:0% +the shuttling to happen more easily +maybe faster and it allows more of them + + align:start position:0% +maybe faster and it allows more of them + + + align:start position:0% +maybe faster and it allows more of them +to be stored + + align:start position:0% +to be stored + + + align:start position:0% +to be stored +per volume it's all about the chemistry + + align:start position:0% +per volume it's all about the chemistry + + + align:start position:0% +per volume it's all about the chemistry +that houses those ions all about the + + align:start position:0% +that houses those ions all about the + + + align:start position:0% +that houses those ions all about the +chemistry of the ions + + align:start position:0% +chemistry of the ions + + + align:start position:0% +chemistry of the ions +so that's why this matters now we we uh + + align:start position:0% +so that's why this matters now we we uh + + + align:start position:0% +so that's why this matters now we we uh +we roll things down hills + + align:start position:0% +we roll things down hills + + + align:start position:0% +we roll things down hills +to power our world i told you this + + align:start position:0% +to power our world i told you this + + + align:start position:0% +to power our world i told you this +already in the first or second lecture + + align:start position:0% +already in the first or second lecture + + + align:start position:0% +already in the first or second lecture +we roll things down hills all the time + + align:start position:0% +we roll things down hills all the time + + + align:start position:0% +we roll things down hills all the time +right so like methane is + + align:start position:0% +right so like methane is + + + align:start position:0% +right so like methane is +you know the core ingredient in natural + + align:start position:0% +you know the core ingredient in natural + + + align:start position:0% +you know the core ingredient in natural +gas and what we do and we talk about + + align:start position:0% +gas and what we do and we talk about + + + align:start position:0% +gas and what we do and we talk about +combustion already + + align:start position:0% +combustion already + + + align:start position:0% +combustion already +is we light that methane on fire but see + + align:start position:0% +is we light that methane on fire but see + + + align:start position:0% +is we light that methane on fire but see +the thing is that what + + align:start position:0% +the thing is that what + + + align:start position:0% +the thing is that what +nature has done is it has put all this + + align:start position:0% +nature has done is it has put all this + + + align:start position:0% +nature has done is it has put all this +stuff + + align:start position:0% +stuff + + + align:start position:0% +stuff +up the hell for us right so + + align:start position:0% +up the hell for us right so + + + align:start position:0% +up the hell for us right so +over tens of millions of years nature + + align:start position:0% +over tens of millions of years nature + + + align:start position:0% +over tens of millions of years nature +has pushed + + align:start position:0% +has pushed + + + align:start position:0% +has pushed +the chemistry up a hill that is + + align:start position:0% +the chemistry up a hill that is + + + align:start position:0% +the chemistry up a hill that is +literally what it's done + + align:start position:0% +literally what it's done + + + align:start position:0% +literally what it's done +right in energy because you know it it's + + align:start position:0% +right in energy because you know it it's + + + align:start position:0% +right in energy because you know it it's +made it so that if i have this rea if i + + align:start position:0% +made it so that if i have this rea if i + + + align:start position:0% +made it so that if i have this rea if i +like this on fire it will go down the + + align:start position:0% +like this on fire it will go down the + + + align:start position:0% +like this on fire it will go down the +hill it will roll down the hill + + align:start position:0% +hill it will roll down the hill + + + align:start position:0% +hill it will roll down the hill +and give off energy right + + align:start position:0% +and give off energy right + + + align:start position:0% +and give off energy right +nature has done that for us but see we + + align:start position:0% +nature has done that for us but see we + + + align:start position:0% +nature has done that for us but see we +need to be able to do this + + align:start position:0% +need to be able to do this + + + align:start position:0% +need to be able to do this +as well as nature and uh and so in the + + align:start position:0% +as well as nature and uh and so in the + + + align:start position:0% +as well as nature and uh and so in the +last + + align:start position:0% +last + + + align:start position:0% +last +uh minute of this why this matters i + + align:start position:0% +uh minute of this why this matters i + + + align:start position:0% +uh minute of this why this matters i +want to explain why this is so + + align:start position:0% +want to explain why this is so + + + align:start position:0% +want to explain why this is so +challenging + + align:start position:0% +challenging + + + align:start position:0% +challenging +we need to be able to match because if + + align:start position:0% +we need to be able to match because if + + + align:start position:0% +we need to be able to match because if +you look at the energy per weight + + align:start position:0% +you look at the energy per weight + + + align:start position:0% +you look at the energy per weight +versus the energy per volume of a + + align:start position:0% +versus the energy per volume of a + + + align:start position:0% +versus the energy per volume of a +material + + align:start position:0% +material + + + align:start position:0% +material +that's a very important metric we plot + + align:start position:0% +that's a very important metric we plot + + + align:start position:0% +that's a very important metric we plot +this all the time if you work on energy + + align:start position:0% +this all the time if you work on energy + + + align:start position:0% +this all the time if you work on energy +materials + + align:start position:0% +materials + + + align:start position:0% +materials +the volumetric versus the gravimetric + + align:start position:0% +the volumetric versus the gravimetric + + + align:start position:0% +the volumetric versus the gravimetric +energy + + align:start position:0% +energy + + + align:start position:0% +energy +density this is good a lot of energy per + + align:start position:0% +density this is good a lot of energy per + + + align:start position:0% +density this is good a lot of energy per +weight and volume well look at where + + align:start position:0% +weight and volume well look at where + + + align:start position:0% +weight and volume well look at where +gasoline is + + align:start position:0% +gasoline is + + + align:start position:0% +gasoline is +now i want to do some math here because + + align:start position:0% +now i want to do some math here because + + + align:start position:0% +now i want to do some math here because +i think this + + align:start position:0% +i think this + + + align:start position:0% +i think this +is very important because i want you to + + align:start position:0% +is very important because i want you to + + + align:start position:0% +is very important because i want you to +see now if i take one liter of gasoline + + align:start position:0% +see now if i take one liter of gasoline + + + align:start position:0% +see now if i take one liter of gasoline +so if i take one liter + + align:start position:0% +so if i take one liter + + + align:start position:0% +so if i take one liter +of gasoline + + align:start position:0% +of gasoline + + + align:start position:0% +of gasoline +now the cost of that is around + + align:start position:0% +now the cost of that is around + + + align:start position:0% +now the cost of that is around +the cost is around a dollar uh + + align:start position:0% +the cost is around a dollar uh + + + align:start position:0% +the cost is around a dollar uh +it fluctuates but you know in this + + align:start position:0% +it fluctuates but you know in this + + + align:start position:0% +it fluctuates but you know in this +country right around now it's about a + + align:start position:0% +country right around now it's about a + + + align:start position:0% +country right around now it's about a +dollar + + align:start position:0% +dollar + + + align:start position:0% +dollar +okay now if i look at how much energy + + align:start position:0% +okay now if i look at how much energy + + + align:start position:0% +okay now if i look at how much energy +is in that gasoline the energy + + align:start position:0% +is in that gasoline the energy + + + align:start position:0% +is in that gasoline the energy +stored in those bonds that nature has + + align:start position:0% +stored in those bonds that nature has + + + align:start position:0% +stored in those bonds that nature has +pushed up a hill over millions of years + + align:start position:0% +pushed up a hill over millions of years + + + align:start position:0% +pushed up a hill over millions of years +the energy stored is about 33 megajoules + + align:start position:0% +the energy stored is about 33 megajoules + + + align:start position:0% +the energy stored is about 33 megajoules +okay good now i'm going to make a + + align:start position:0% +okay good now i'm going to make a + + + align:start position:0% +okay good now i'm going to make a +comparison + + align:start position:0% +comparison + + + align:start position:0% +comparison +one mit professor + + align:start position:0% +one mit professor + + + align:start position:0% +one mit professor +one nit + + align:start position:0% +one nit + + + align:start position:0% +one nit +professor operates + + align:start position:0% +professor operates + + + align:start position:0% +professor operates +at around 60 watts now + + align:start position:0% +at around 60 watts now + + + align:start position:0% +at around 60 watts now +this is something like well this is + + align:start position:0% +this is something like well this is + + + align:start position:0% +this is something like well this is +equal to + + align:start position:0% +equal to + + + align:start position:0% +equal to +60 joules per second now i know some + + align:start position:0% +60 joules per second now i know some + + + align:start position:0% +60 joules per second now i know some +professors who can operate a little + + align:start position:0% +professors who can operate a little + + + align:start position:0% +professors who can operate a little +higher than that + + align:start position:0% +higher than that + + + align:start position:0% +higher than that +maybe some a little lower but that's + + align:start position:0% +maybe some a little lower but that's + + + align:start position:0% +maybe some a little lower but that's +like the average right + + align:start position:0% +like the average right + + + align:start position:0% +like the average right +60 joules per second now the thing is if + + align:start position:0% +60 joules per second now the thing is if + + + align:start position:0% +60 joules per second now the thing is if +i want to get + + align:start position:0% +i want to get + + + align:start position:0% +i want to get +33 mega joules out of this professor + + align:start position:0% +33 mega joules out of this professor + + + align:start position:0% +33 mega joules out of this professor +then i get i get at this rate 33 + + align:start position:0% +then i get i get at this rate 33 + + + align:start position:0% +then i get i get at this rate 33 +megajoules takes the prof + + align:start position:0% +megajoules takes the prof + + + align:start position:0% +megajoules takes the prof +um uh 153 hours + + align:start position:0% +um uh 153 hours + + + align:start position:0% +um uh 153 hours +now here's why this matters because 153 + + align:start position:0% +now here's why this matters because 153 + + + align:start position:0% +now here's why this matters because 153 +hours will cost about fifteen hundred + + align:start position:0% +hours will cost about fifteen hundred + + + align:start position:0% +hours will cost about fifteen hundred +and thirty dollars at + + align:start position:0% +and thirty dollars at + + + align:start position:0% +and thirty dollars at +the uh mit uh professor salary + + align:start position:0% +the uh mit uh professor salary + + + align:start position:0% +the uh mit uh professor salary +uh which is around + + align:start position:0% +uh which is around + + + align:start position:0% +uh which is around +ten dollars per hour okay + + align:start position:0% +ten dollars per hour okay + + + align:start position:0% +ten dollars per hour okay +and okay but look at this + + align:start position:0% + + + + align:start position:0% + +i dug something out of the ground that + + align:start position:0% +i dug something out of the ground that + + + align:start position:0% +i dug something out of the ground that +nature spent 100 million years making + + align:start position:0% +nature spent 100 million years making + + + align:start position:0% +nature spent 100 million years making +fine + + align:start position:0% +fine + + + align:start position:0% +fine +okay and i burned it and i got it for a + + align:start position:0% +okay and i burned it and i got it for a + + + align:start position:0% +okay and i burned it and i got it for a +dollar i got the same amount of energy + + align:start position:0% +dollar i got the same amount of energy + + + align:start position:0% +dollar i got the same amount of energy +that it would have taken me + + align:start position:0% +that it would have taken me + + + align:start position:0% +that it would have taken me +literally fifteen hundred and thirty + + align:start position:0% +literally fifteen hundred and thirty + + + align:start position:0% +literally fifteen hundred and thirty +dollars to pay for + + align:start position:0% +dollars to pay for + + + align:start position:0% +dollars to pay for +that's our challenge right that's our + + align:start position:0% +that's our challenge right that's our + + + align:start position:0% +that's our challenge right that's our +because now you can plot other things + + align:start position:0% +because now you can plot other things + + + align:start position:0% +because now you can plot other things +here but look at this ethanol wood okay + + align:start position:0% +here but look at this ethanol wood okay + + + align:start position:0% +here but look at this ethanol wood okay +liquid hydrogen we're still trying to + + align:start position:0% +liquid hydrogen we're still trying to + + + align:start position:0% +liquid hydrogen we're still trying to +compress it get but look at this + + align:start position:0% +compress it get but look at this + + + align:start position:0% +compress it get but look at this +batteries are way down there this is why + + align:start position:0% +batteries are way down there this is why + + + align:start position:0% +batteries are way down there this is why +this matters because we're not even + + align:start position:0% +this matters because we're not even + + + align:start position:0% +this matters because we're not even +close to being done + + align:start position:0% +close to being done + + + align:start position:0% +close to being done +we're not even close see that great + + align:start position:0% +we're not even close see that great + + + align:start position:0% +we're not even close see that great +uptick in electrochemical storage + + align:start position:0% +uptick in electrochemical storage + + + align:start position:0% +uptick in electrochemical storage +we need another order or two of + + align:start position:0% +we need another order or two of + + + align:start position:0% +we need another order or two of +magnitude still + + align:start position:0% +magnitude still + + + align:start position:0% +magnitude still +right in storing energy efficiencies + + align:start position:0% +right in storing energy efficiencies + + + align:start position:0% +right in storing energy efficiencies +costs etc so that's uh that's my why + + align:start position:0% +costs etc so that's uh that's my why + + + align:start position:0% +costs etc so that's uh that's my why +this matters for + + align:start position:0% +this matters for + + + align:start position:0% +this matters for +today now back to ions and electrons and + + align:start position:0% +today now back to ions and electrons and + + + align:start position:0% +today now back to ions and electrons and +atoms + + align:start position:0% +atoms + + + align:start position:0% +atoms +what i want to take the last 15 minutes + + align:start position:0% +what i want to take the last 15 minutes + + + align:start position:0% +what i want to take the last 15 minutes +of class is to introduce a new way of + + align:start position:0% +of class is to introduce a new way of + + + align:start position:0% +of class is to introduce a new way of +looking at this and some of you may have + + align:start position:0% +looking at this and some of you may have + + + align:start position:0% +looking at this and some of you may have +seen the lewis dots + + align:start position:0% +seen the lewis dots + + + align:start position:0% +seen the lewis dots +okay um we're gonna + + align:start position:0% +okay um we're gonna + + + align:start position:0% +okay um we're gonna +i'm gonna introduce them today and then + + align:start position:0% +i'm gonna introduce them today and then + + + align:start position:0% +i'm gonna introduce them today and then +we're gonna make a whole bunch of + + align:start position:0% +we're gonna make a whole bunch of + + + align:start position:0% +we're gonna make a whole bunch of +molecular structures on wednesday + + align:start position:0% +molecular structures on wednesday + + + align:start position:0% +molecular structures on wednesday +um and the reason this is so important + + align:start position:0% +um and the reason this is so important + + + align:start position:0% +um and the reason this is so important +is that it gives us a sense + + align:start position:0% +is that it gives us a sense + + + align:start position:0% +is that it gives us a sense +of these outer electrons it gives us a + + align:start position:0% +of these outer electrons it gives us a + + + align:start position:0% +of these outer electrons it gives us a +sense + + align:start position:0% +sense + + + align:start position:0% +sense +of how those outer electrons look right + + align:start position:0% +of how those outer electrons look right + + + align:start position:0% +of how those outer electrons look right +for the atoms and then very importantly + + align:start position:0% +for the atoms and then very importantly + + + align:start position:0% +for the atoms and then very importantly +how they come together in bonds + + align:start position:0% +how they come together in bonds + + + align:start position:0% +how they come together in bonds +okay how they come together in bots so + + align:start position:0% +okay how they come together in bots so + + + align:start position:0% +okay how they come together in bots so +um + + align:start position:0% +um + + + align:start position:0% +um +so if i uh + + align:start position:0% + + + + align:start position:0% + +just very very simply ask what is + + align:start position:0% +just very very simply ask what is + + + align:start position:0% +just very very simply ask what is +you know what is the lewis dot + + align:start position:0% +you know what is the lewis dot + + + align:start position:0% +you know what is the lewis dot +structure look like well + + align:start position:0% + + + + align:start position:0% + +first of all the number of dots + + align:start position:0% + + + + align:start position:0% + +is equal to the number of + + align:start position:0% +is equal to the number of + + + align:start position:0% +is equal to the number of +valence electrons + + align:start position:0% + + + + align:start position:0% + +and this is equal to the last digit + + align:start position:0% +and this is equal to the last digit + + + align:start position:0% +and this is equal to the last digit +of the group so + + align:start position:0% +of the group so + + + align:start position:0% +of the group so +of the element group i'll show you that + + align:start position:0% +of the element group i'll show you that + + + align:start position:0% +of the element group i'll show you that +in a second + + align:start position:0% +in a second + + + align:start position:0% +in a second +okay so there's lewis now lewis um + + align:start position:0% +okay so there's lewis now lewis um + + + align:start position:0% +okay so there's lewis now lewis um +you know he's so there's one of his his + + align:start position:0% +you know he's so there's one of his his + + + align:start position:0% +you know he's so there's one of his his +drawings in one of his original papers + + align:start position:0% +drawings in one of his original papers + + + align:start position:0% +drawings in one of his original papers +in the early 1900s + + align:start position:0% +in the early 1900s + + + align:start position:0% +in the early 1900s +he actually was a professor here as well + + align:start position:0% +he actually was a professor here as well + + + align:start position:0% +he actually was a professor here as well +um and then he he went and did some of + + align:start position:0% +um and then he he went and did some of + + + align:start position:0% +um and then he he went and did some of +this a lot of this work out in berkeley + + align:start position:0% +this a lot of this work out in berkeley + + + align:start position:0% +this a lot of this work out in berkeley +so they named the hall after him + + align:start position:0% +so they named the hall after him + + + align:start position:0% +so they named the hall after him +um and his comprehension was absolutely + + align:start position:0% +um and his comprehension was absolutely + + + align:start position:0% +um and his comprehension was absolutely +profound + + align:start position:0% +profound + + + align:start position:0% +profound +because in thinking about + + align:start position:0% +because in thinking about + + + align:start position:0% +because in thinking about +atoms with dots to represent electrons + + align:start position:0% +atoms with dots to represent electrons + + + align:start position:0% +atoms with dots to represent electrons +in the outer valence it gave us a way + + align:start position:0% +in the outer valence it gave us a way + + + align:start position:0% +in the outer valence it gave us a way +to so easily think about bonding + + align:start position:0% +to so easily think about bonding + + + align:start position:0% +to so easily think about bonding +okay now we can think about ionic + + align:start position:0% +okay now we can think about ionic + + + align:start position:0% +okay now we can think about ionic +bonding for sure which is what we've + + align:start position:0% +bonding for sure which is what we've + + + align:start position:0% +bonding for sure which is what we've +done + + align:start position:0% +done + + + align:start position:0% +done +but more importantly what lewis helps us + + align:start position:0% +but more importantly what lewis helps us + + + align:start position:0% +but more importantly what lewis helps us +with is to think about + + align:start position:0% +with is to think about + + + align:start position:0% +with is to think about +covalent bonding and that's the subject + + align:start position:0% +covalent bonding and that's the subject + + + align:start position:0% +covalent bonding and that's the subject +of wednesday okay which is a whole + + align:start position:0% +of wednesday okay which is a whole + + + align:start position:0% +of wednesday okay which is a whole +another type of bonding that we're going + + align:start position:0% +another type of bonding that we're going + + + align:start position:0% +another type of bonding that we're going +to talk about + + align:start position:0% +to talk about + + + align:start position:0% +to talk about +okay now okay so now uh last digit of + + align:start position:0% +okay now okay so now uh last digit of + + + align:start position:0% +okay now okay so now uh last digit of +the element group okay good so there it + + align:start position:0% +the element group okay good so there it + + + align:start position:0% +the element group okay good so there it +predicts the number of bonds formed by + + align:start position:0% +predicts the number of bonds formed by + + + align:start position:0% +predicts the number of bonds formed by +most elements in their compounds good + + align:start position:0% +most elements in their compounds good + + + align:start position:0% +most elements in their compounds good +and there's the dots look at that + + align:start position:0% +and there's the dots look at that + + + align:start position:0% +and there's the dots look at that +example fluorine + + align:start position:0% +example fluorine + + + align:start position:0% +example fluorine +or using noble gas notation + + align:start position:0% +or using noble gas notation + + + align:start position:0% +or using noble gas notation +helium that really saved us time i + + align:start position:0% +helium that really saved us time i + + + align:start position:0% +helium that really saved us time i +didn't have to write one s2 + + align:start position:0% +didn't have to write one s2 + + + align:start position:0% +didn't have to write one s2 +actually this looks like four strokes of + + align:start position:0% +actually this looks like four strokes of + + + align:start position:0% +actually this looks like four strokes of +the pen one s2 would have been three + + align:start position:0% +the pen one s2 would have been three + + + align:start position:0% +the pen one s2 would have been three +i don't know honestly but anyway uh okay + + align:start position:0% +i don't know honestly but anyway uh okay + + + align:start position:0% +i don't know honestly but anyway uh okay +there's fluorine and look one dot no + + align:start position:0% +there's fluorine and look one dot no + + + align:start position:0% +there's fluorine and look one dot no +two dots no because you add a dot for + + align:start position:0% +two dots no because you add a dot for + + + align:start position:0% +two dots no because you add a dot for +the valence so fluorine + + align:start position:0% +the valence so fluorine + + + align:start position:0% +the valence so fluorine +has seven dots until you reach the + + align:start position:0% +has seven dots until you reach the + + + align:start position:0% +has seven dots until you reach the +valence + + align:start position:0% +valence + + + align:start position:0% +valence +until you reach the valence that is the + + align:start position:0% +until you reach the valence that is the + + + align:start position:0% +until you reach the valence that is the +key + + align:start position:0% +key + + + align:start position:0% +key +of the of the lewis picture because we + + align:start position:0% +of the of the lewis picture because we + + + align:start position:0% +of the of the lewis picture because we +and we talked about this before + + align:start position:0% +and we talked about this before + + + align:start position:0% +and we talked about this before +we talked about this before because so + + align:start position:0% +we talked about this before because so + + + align:start position:0% +we talked about this before because so +there are three + + align:start position:0% +there are three + + + align:start position:0% +there are three +really important things that come out of + + align:start position:0% +really important things that come out of + + + align:start position:0% +really important things that come out of +the lewis picture + + align:start position:0% +the lewis picture + + + align:start position:0% +the lewis picture +one is it tells us + + align:start position:0% +one is it tells us + + + align:start position:0% +one is it tells us +as i've just told you it tells us about + + align:start position:0% +as i've just told you it tells us about + + + align:start position:0% +as i've just told you it tells us about +bond formation + + align:start position:0% + + + + align:start position:0% + +tells us about bond formation and + + align:start position:0% +tells us about bond formation and + + + align:start position:0% +tells us about bond formation and +it makes the assumption that the valence + + align:start position:0% +it makes the assumption that the valence + + + align:start position:0% +it makes the assumption that the valence +electrons + + align:start position:0% + + + + align:start position:0% + +are what matter + + align:start position:0% + + + + align:start position:0% + +for chemistry and this is critical and + + align:start position:0% +for chemistry and this is critical and + + + align:start position:0% +for chemistry and this is critical and +i've alluded to this before + + align:start position:0% +i've alluded to this before + + + align:start position:0% +i've alluded to this before +you now have a real sense of this though + + align:start position:0% +you now have a real sense of this though + + + align:start position:0% +you now have a real sense of this though +from these energy diagrams you have a + + align:start position:0% +from these energy diagrams you have a + + + align:start position:0% +from these energy diagrams you have a +sense of this + + align:start position:0% +sense of this + + + align:start position:0% +sense of this +because look if i want to rip an + + align:start position:0% +because look if i want to rip an + + + align:start position:0% +because look if i want to rip an +electron off of lithium i got to spend + + align:start position:0% +electron off of lithium i got to spend + + + align:start position:0% +electron off of lithium i got to spend +5.4 electron volts + + align:start position:0% +5.4 electron volts + + + align:start position:0% +5.4 electron volts +if i want to rip the next one off i got + + align:start position:0% +if i want to rip the next one off i got + + + align:start position:0% +if i want to rip the next one off i got +to spend over a hundred electron volts + + align:start position:0% +to spend over a hundred electron volts + + + align:start position:0% +to spend over a hundred electron volts +and we say well we'll do pes with all + + align:start position:0% +and we say well we'll do pes with all + + + align:start position:0% +and we say well we'll do pes with all +these + + align:start position:0% +these + + + align:start position:0% +these +energies it doesn't matter i'll get them + + align:start position:0% +energies it doesn't matter i'll get them + + + align:start position:0% +energies it doesn't matter i'll get them +all but what if i just want to say well + + align:start position:0% +all but what if i just want to say well + + + align:start position:0% +all but what if i just want to say well +who's going to you know what what + + align:start position:0% +who's going to you know what what + + + align:start position:0% +who's going to you know what what +electrons are going to be + + align:start position:0% +electrons are going to be + + + align:start position:0% +electrons are going to be +available to participate + + align:start position:0% +available to participate + + + align:start position:0% +available to participate +in something like a bond which ones it's + + align:start position:0% +in something like a bond which ones it's + + + align:start position:0% +in something like a bond which ones it's +going to be these ones + + align:start position:0% +going to be these ones + + + align:start position:0% +going to be these ones +it's not going to be the ones all the + + align:start position:0% +it's not going to be the ones all the + + + align:start position:0% +it's not going to be the ones all the +way in close to the core + + align:start position:0% +way in close to the core + + + align:start position:0% +way in close to the core +that don't want to be bothered and + + align:start position:0% +that don't want to be bothered and + + + align:start position:0% +that don't want to be bothered and +they've got so much energy + + align:start position:0% +they've got so much energy + + + align:start position:0% +they've got so much energy +just to get their attention takes 100 ev + + align:start position:0% +just to get their attention takes 100 ev + + + align:start position:0% +just to get their attention takes 100 ev +and even that's not a but here a little + + align:start position:0% +and even that's not a but here a little + + + align:start position:0% +and even that's not a but here a little +visible light + + align:start position:0% +visible light + + + align:start position:0% +visible light +and i got i got lithium talking to me + + align:start position:0% +and i got i got lithium talking to me + + + align:start position:0% +and i got i got lithium talking to me +well it's the same you know chemically + + align:start position:0% +well it's the same you know chemically + + + align:start position:0% +well it's the same you know chemically +it's the same these + + align:start position:0% +it's the same these + + + align:start position:0% +it's the same these +that's light right these are these ones + + align:start position:0% +that's light right these are these ones + + + align:start position:0% +that's light right these are these ones +are the ones + + align:start position:0% +are the ones + + + align:start position:0% +are the ones +that want to and can participate in + + align:start position:0% +that want to and can participate in + + + align:start position:0% +that want to and can participate in +bonding + + align:start position:0% +bonding + + + align:start position:0% +bonding +the ones all the way down in energy way + + align:start position:0% +the ones all the way down in energy way + + + align:start position:0% +the ones all the way down in energy way +way way low + + align:start position:0% +way way low + + + align:start position:0% +way way low +they're inert they're inert right + + align:start position:0% +they're inert they're inert right + + + align:start position:0% +they're inert they're inert right +so most of chemistry happens in the + + align:start position:0% +so most of chemistry happens in the + + + align:start position:0% +so most of chemistry happens in the +violence and lewis + + align:start position:0% +violence and lewis + + + align:start position:0% +violence and lewis +really nailed that right so these dots + + align:start position:0% +really nailed that right so these dots + + + align:start position:0% +really nailed that right so these dots +are only + + align:start position:0% +are only + + + align:start position:0% +are only +valence electron dots + + align:start position:0% + + + + align:start position:0% + +and there's one more rule now okay so + + align:start position:0% +and there's one more rule now okay so + + + align:start position:0% +and there's one more rule now okay so +there's those seven dots for fluorine + + align:start position:0% +there's those seven dots for fluorine + + + align:start position:0% +there's those seven dots for fluorine +and then okay sometimes + + align:start position:0% +and then okay sometimes + + + align:start position:0% +and then okay sometimes +you'll see this oh this is just the + + align:start position:0% +you'll see this oh this is just the + + + align:start position:0% +you'll see this oh this is just the +number of dots it's this classification + + align:start position:0% +number of dots it's this classification + + + align:start position:0% +number of dots it's this classification +of the uh of the columns + + align:start position:0% +of the uh of the columns + + + align:start position:0% +of the uh of the columns +right the groups in the pair but no that + + align:start position:0% +right the groups in the pair but no that + + + align:start position:0% +right the groups in the pair but no that +is not okay + + align:start position:0% +is not okay + + + align:start position:0% +is not okay +not standard remember the iupac + + align:start position:0% +not standard remember the iupac + + + align:start position:0% +not standard remember the iupac +which throws the best most lively + + align:start position:0% +which throws the best most lively + + + align:start position:0% +which throws the best most lively +parties + + align:start position:0% +parties + + + align:start position:0% +parties +and conferences they decide on how to + + align:start position:0% +and conferences they decide on how to + + + align:start position:0% +and conferences they decide on how to +name elements and many many + + align:start position:0% +name elements and many many + + + align:start position:0% +name elements and many many +other aspects of our lives are decided + + align:start position:0% +other aspects of our lives are decided + + + align:start position:0% +other aspects of our lives are decided +by them and they said no + + align:start position:0% +by them and they said no + + + align:start position:0% +by them and they said no +that's an old classification it's + + align:start position:0% +that's an old classification it's + + + align:start position:0% +that's an old classification it's +confusing so we're going to go + + align:start position:0% +confusing so we're going to go + + + align:start position:0% +confusing so we're going to go +with the standard which is that we still + + align:start position:0% +with the standard which is that we still + + + align:start position:0% +with the standard which is that we still +count 1 to 18 + + align:start position:0% +count 1 to 18 + + + align:start position:0% +count 1 to 18 +1 to 18 1 2 s block + + align:start position:0% +1 to 18 1 2 s block + + + align:start position:0% +1 to 18 1 2 s block +13 to 18 p block right + + align:start position:0% +13 to 18 p block right + + + align:start position:0% +13 to 18 p block right +right okay that's cool we now right + + align:start position:0% +right okay that's cool we now right + + + align:start position:0% +right okay that's cool we now right +3 to 12. d block oh + + align:start position:0% +3 to 12. d block oh + + + align:start position:0% +3 to 12. d block oh +we go back and forth but it's still but + + align:start position:0% +we go back and forth but it's still but + + + align:start position:0% +we go back and forth but it's still but +you can just take the last digit there + + align:start position:0% +you can just take the last digit there + + + align:start position:0% +you can just take the last digit there +iupac even the periodic table talks + + align:start position:0% +iupac even the periodic table talks + + + align:start position:0% +iupac even the periodic table talks +about it + + align:start position:0% +about it + + + align:start position:0% +about it +it shows it it shows the old + + align:start position:0% +it shows it it shows the old + + + align:start position:0% +it shows it it shows the old +classification there and then it says no + + align:start position:0% +classification there and then it says no + + + align:start position:0% +classification there and then it says no +don't use it it's confusing and then why + + align:start position:0% +don't use it it's confusing and then why + + + align:start position:0% +don't use it it's confusing and then why +do they show it + + align:start position:0% +do they show it + + + align:start position:0% +do they show it +because some textbooks still show it so + + align:start position:0% +because some textbooks still show it so + + + align:start position:0% +because some textbooks still show it so +you so i want + + align:start position:0% +you so i want + + + align:start position:0% +you so i want +you to be aware of that okay + + align:start position:0% +you to be aware of that okay + + + align:start position:0% +you to be aware of that okay +now you can use + + align:start position:0% +now you can use + + + align:start position:0% +now you can use +louis you can use this idea of only + + align:start position:0% +louis you can use this idea of only + + + align:start position:0% +louis you can use this idea of only +thinking about the the valence + + align:start position:0% +thinking about the the valence + + + align:start position:0% +thinking about the the valence +to understand when atoms have similar + + align:start position:0% +to understand when atoms have similar + + + align:start position:0% +to understand when atoms have similar +chemistry + + align:start position:0% +chemistry + + + align:start position:0% +chemistry +right so if the valence of carbon + + align:start position:0% +right so if the valence of carbon + + + align:start position:0% +right so if the valence of carbon +is the same as the balance of silicon + + align:start position:0% +is the same as the balance of silicon + + + align:start position:0% +is the same as the balance of silicon +you bump down one quantum number + + align:start position:0% +you bump down one quantum number + + + align:start position:0% +you bump down one quantum number +but they both have four electrons out + + align:start position:0% +but they both have four electrons out + + + align:start position:0% +but they both have four electrons out +there in the valence + + align:start position:0% +there in the valence + + + align:start position:0% +there in the valence +in this case it's two in this case it's + + align:start position:0% +in this case it's two in this case it's + + + align:start position:0% +in this case it's two in this case it's +three in terms of quantum number but + + align:start position:0% +three in terms of quantum number but + + + align:start position:0% +three in terms of quantum number but +they both have those same + + align:start position:0% +they both have those same + + + align:start position:0% +they both have those same +kinds of and same number of electrons so + + align:start position:0% +kinds of and same number of electrons so + + + align:start position:0% +kinds of and same number of electrons so +you could maybe expect + + align:start position:0% +you could maybe expect + + + align:start position:0% +you could maybe expect +there to be similar chemistry it turns + + align:start position:0% +there to be similar chemistry it turns + + + align:start position:0% +there to be similar chemistry it turns +out in this case + + align:start position:0% +out in this case + + + align:start position:0% +out in this case +there's very different but we'll learn + + align:start position:0% +there's very different but we'll learn + + + align:start position:0% +there's very different but we'll learn +about that carbon hybridization + + align:start position:0% +about that carbon hybridization + + + align:start position:0% +about that carbon hybridization +silicon no we'll get to that + + align:start position:0% +silicon no we'll get to that + + + align:start position:0% +silicon no we'll get to that +but still this is how we see silicon now + + align:start position:0% +but still this is how we see silicon now + + + align:start position:0% +but still this is how we see silicon now +we don't see it this way with lewis + + align:start position:0% +we don't see it this way with lewis + + + align:start position:0% +we don't see it this way with lewis +we see it this way this is how we see + + align:start position:0% +we see it this way this is how we see + + + align:start position:0% +we see it this way this is how we see +carbon + + align:start position:0% +carbon + + + align:start position:0% +carbon +right and so i want you to start seeing + + align:start position:0% +right and so i want you to start seeing + + + align:start position:0% +right and so i want you to start seeing +elements this way + + align:start position:0% +elements this way + + + align:start position:0% +elements this way +okay and so you can look at periodic + + align:start position:0% +okay and so you can look at periodic + + + align:start position:0% +okay and so you can look at periodic +tables and and take images randomly + + align:start position:0% +tables and and take images randomly + + + align:start position:0% +tables and and take images randomly +found online + + align:start position:0% +found online + + + align:start position:0% +found online +with lewis dots and you can start + + align:start position:0% +with lewis dots and you can start + + + align:start position:0% +with lewis dots and you can start +thinking + + align:start position:0% +thinking + + + align:start position:0% +thinking +of atoms as their lewis dot + + align:start position:0% +of atoms as their lewis dot + + + align:start position:0% +of atoms as their lewis dot +representation + + align:start position:0% +representation + + + align:start position:0% +representation +okay and like i said on wednesday we're + + align:start position:0% +okay and like i said on wednesday we're + + + align:start position:0% +okay and like i said on wednesday we're +going to make a whole bunch of + + align:start position:0% +going to make a whole bunch of + + + align:start position:0% +going to make a whole bunch of +structures molecules + + align:start position:0% +structures molecules + + + align:start position:0% +structures molecules +with lewis dots and and show how that + + align:start position:0% +with lewis dots and and show how that + + + align:start position:0% +with lewis dots and and show how that +teaches us + + align:start position:0% +teaches us + + + align:start position:0% +teaches us +not only about how to draw the bonds but + + align:start position:0% +not only about how to draw the bonds but + + + align:start position:0% +not only about how to draw the bonds but +literally about which config which + + align:start position:0% +literally about which config which + + + align:start position:0% +literally about which config which +bonding if i have sodium and chlorine + + align:start position:0% +bonding if i have sodium and chlorine + + + align:start position:0% +bonding if i have sodium and chlorine +it's pretty obvious + + align:start position:0% +it's pretty obvious + + + align:start position:0% +it's pretty obvious +if there's a bond it's between sodium + + align:start position:0% +if there's a bond it's between sodium + + + align:start position:0% +if there's a bond it's between sodium +and chlorine + + align:start position:0% +and chlorine + + + align:start position:0% +and chlorine +right but as i go to more and more atoms + + align:start position:0% +right but as i go to more and more atoms + + + align:start position:0% +right but as i go to more and more atoms +and i'm trying to form molecules + + align:start position:0% +and i'm trying to form molecules + + + align:start position:0% +and i'm trying to form molecules +it's not so obvious what is bonded to + + align:start position:0% +it's not so obvious what is bonded to + + + align:start position:0% +it's not so obvious what is bonded to +what + + align:start position:0% +what + + + align:start position:0% +what +and how right and thinking about + + align:start position:0% +and how right and thinking about + + + align:start position:0% +and how right and thinking about +this and thinking about the third + + align:start position:0% +this and thinking about the third + + + align:start position:0% +this and thinking about the third +part of what lewis did that was so + + align:start position:0% +part of what lewis did that was so + + + align:start position:0% +part of what lewis did that was so +important + + align:start position:0% +important + + + align:start position:0% +important +is what allows us to draw a whole bunch + + align:start position:0% +is what allows us to draw a whole bunch + + + align:start position:0% +is what allows us to draw a whole bunch +of molecules octet rule + + align:start position:0% +of molecules octet rule + + + align:start position:0% +of molecules octet rule +which is that atoms + + align:start position:0% +which is that atoms + + + align:start position:0% +which is that atoms +like + + align:start position:0% + + + + align:start position:0% + +and we now know like means + + align:start position:0% +and we now know like means + + + align:start position:0% +and we now know like means +lower energy to reach eight + + align:start position:0% +lower energy to reach eight + + + align:start position:0% +lower energy to reach eight +electrons in + + align:start position:0% + + + + align:start position:0% + +their valence okay well we can already + + align:start position:0% +their valence okay well we can already + + + align:start position:0% +their valence okay well we can already +see this + + align:start position:0% +see this + + + align:start position:0% +see this +for the ionic bond that we've talked + + align:start position:0% +for the ionic bond that we've talked + + + align:start position:0% +for the ionic bond that we've talked +about and you can + + align:start position:0% +about and you can + + + align:start position:0% +about and you can +you can write this and i want you to + + align:start position:0% +you can write this and i want you to + + + align:start position:0% +you can write this and i want you to +write ionic bonds + + align:start position:0% +write ionic bonds + + + align:start position:0% +write ionic bonds +using lewis but in this case it's + + align:start position:0% +using lewis but in this case it's + + + align:start position:0% +using lewis but in this case it's +actually pretty + + align:start position:0% +actually pretty + + + align:start position:0% +actually pretty +straightforward right if i had for + + align:start position:0% +straightforward right if i had for + + + align:start position:0% +straightforward right if i had for +example uh let's + + align:start position:0% +example uh let's + + + align:start position:0% +example uh let's +let's get some more board space + + align:start position:0% +let's get some more board space + + + align:start position:0% +let's get some more board space +over here + + align:start position:0% + + + + align:start position:0% + +if i had for example an ionic bond + + align:start position:0% +if i had for example an ionic bond + + + align:start position:0% +if i had for example an ionic bond +between cesium and fluorine + + align:start position:0% +between cesium and fluorine + + + align:start position:0% +between cesium and fluorine +so if i had cesium + + align:start position:0% + + + + align:start position:0% + +and fluorine then the way i would think + + align:start position:0% +and fluorine then the way i would think + + + align:start position:0% +and fluorine then the way i would think +about this + + align:start position:0% +about this + + + align:start position:0% +about this +in the lewis world would be + + align:start position:0% +in the lewis world would be + + + align:start position:0% +in the lewis world would be +this way and + + align:start position:0% +this way and + + + align:start position:0% +this way and +this way + + align:start position:0% + + + + align:start position:0% + +because i've got seven valence electrons + + align:start position:0% +because i've got seven valence electrons + + + align:start position:0% +because i've got seven valence electrons +in fluorine and one in cesium + + align:start position:0% +in fluorine and one in cesium + + + align:start position:0% +in fluorine and one in cesium +and then if i write this as an ionic + + align:start position:0% +and then if i write this as an ionic + + + align:start position:0% +and then if i write this as an ionic +bond the way i would write it is + + align:start position:0% +bond the way i would write it is + + + align:start position:0% +bond the way i would write it is +cesium plus + + align:start position:0% +cesium plus + + + align:start position:0% +cesium plus +with fluorine having taken + + align:start position:0% +with fluorine having taken + + + align:start position:0% +with fluorine having taken +that electron now i'm not + + align:start position:0% +that electron now i'm not + + + align:start position:0% +that electron now i'm not +and so you would write this still with + + align:start position:0% +and so you would write this still with + + + align:start position:0% +and so you would write this still with +the minus sign there that emphasizes + + align:start position:0% +the minus sign there that emphasizes + + + align:start position:0% +the minus sign there that emphasizes +it emphasizes what happened but i see my + + align:start position:0% +it emphasizes what happened but i see my + + + align:start position:0% +it emphasizes what happened but i see my +lewis here + + align:start position:0% +lewis here + + + align:start position:0% +lewis here +you know i see it there but i'm + + align:start position:0% +you know i see it there but i'm + + + align:start position:0% +you know i see it there but i'm +emphasizing that this is an ionic + + align:start position:0% +emphasizing that this is an ionic + + + align:start position:0% +emphasizing that this is an ionic +bond that's happened because fluorine + + align:start position:0% +bond that's happened because fluorine + + + align:start position:0% +bond that's happened because fluorine +has wasn't supposed to have eight but + + align:start position:0% +has wasn't supposed to have eight but + + + align:start position:0% +has wasn't supposed to have eight but +then it did + + align:start position:0% +then it did + + + align:start position:0% +then it did +it's got a super high electron affinity + + align:start position:0% +it's got a super high electron affinity + + + align:start position:0% +it's got a super high electron affinity +cesium has a very low ionization energy + + align:start position:0% +cesium has a very low ionization energy + + + align:start position:0% +cesium has a very low ionization energy +of its first electron + + align:start position:0% +of its first electron + + + align:start position:0% +of its first electron +and so fluorine just took it it + + align:start position:0% +and so fluorine just took it it + + + align:start position:0% +and so fluorine just took it it +literally just took it + + align:start position:0% +literally just took it + + + align:start position:0% +literally just took it +i'll take that thank you very much you + + align:start position:0% +i'll take that thank you very much you + + + align:start position:0% +i'll take that thank you very much you +know i'm not being judgmental + + align:start position:0% +know i'm not being judgmental + + + align:start position:0% +know i'm not being judgmental +but ionic bonds are kind of you know the + + align:start position:0% +but ionic bonds are kind of you know the + + + align:start position:0% +but ionic bonds are kind of you know the +relationship + + align:start position:0% +relationship + + + align:start position:0% +relationship +in a bond and i don't want to judge but + + align:start position:0% +in a bond and i don't want to judge but + + + align:start position:0% +in a bond and i don't want to judge but +the relationship is not even + + align:start position:0% +the relationship is not even + + + align:start position:0% +the relationship is not even +it's not even and it's okay but they + + align:start position:0% +it's not even and it's okay but they + + + align:start position:0% +it's not even and it's okay but they +because what flooring said take + + align:start position:0% +because what flooring said take + + + align:start position:0% +because what flooring said take +take give and see okay fine + + align:start position:0% +take give and see okay fine + + + align:start position:0% +take give and see okay fine +now on wednesday when we do covalent + + align:start position:0% +now on wednesday when we do covalent + + + align:start position:0% +now on wednesday when we do covalent +bonds it's not so then there's a lot + + align:start position:0% +bonds it's not so then there's a lot + + + align:start position:0% +bonds it's not so then there's a lot +more sharing + + align:start position:0% +more sharing + + + align:start position:0% +more sharing +that happens but here and that's why we + + align:start position:0% +that happens but here and that's why we + + + align:start position:0% +that happens but here and that's why we +can model + + align:start position:0% +can model + + + align:start position:0% +can model +it the way that i yes i still left there + + align:start position:0% +it the way that i yes i still left there + + + align:start position:0% +it the way that i yes i still left there +we can model it that way + + align:start position:0% +we can model it that way + + + align:start position:0% +we can model it that way +because it is like a charged atom in + + align:start position:0% +because it is like a charged atom in + + + align:start position:0% +because it is like a charged atom in +another charged atom + + align:start position:0% +another charged atom + + + align:start position:0% +another charged atom +right and it's because flooring took it + + align:start position:0% +right and it's because flooring took it + + + align:start position:0% +right and it's because flooring took it +laureen took it it's okay any kind of + + align:start position:0% +laureen took it it's okay any kind of + + + align:start position:0% +laureen took it it's okay any kind of +relationship + + align:start position:0% +relationship + + + align:start position:0% +relationship +you know they get along they make it + + align:start position:0% +you know they get along they make it + + + align:start position:0% +you know they get along they make it +work now + + align:start position:0% + + + + align:start position:0% + +what we can also do and just in thinking + + align:start position:0% +what we can also do and just in thinking + + + align:start position:0% +what we can also do and just in thinking +about this + + align:start position:0% +about this + + + align:start position:0% +about this +just in thinking about this i could go + + align:start position:0% +just in thinking about this i could go + + + align:start position:0% +just in thinking about this i could go +to another example like calcium + + align:start position:0% +to another example like calcium + + + align:start position:0% +to another example like calcium +and if i think about calcium and + + align:start position:0% +and if i think about calcium and + + + align:start position:0% +and if i think about calcium and +fluorine well i know again fluorine + + align:start position:0% +fluorine well i know again fluorine + + + align:start position:0% +fluorine well i know again fluorine +likes to be f minus but see calcium when + + align:start position:0% +likes to be f minus but see calcium when + + + align:start position:0% +likes to be f minus but see calcium when +i think about it as a lewis + + align:start position:0% +i think about it as a lewis + + + align:start position:0% +i think about it as a lewis +atom yeah calcium likes to lose both of + + align:start position:0% +atom yeah calcium likes to lose both of + + + align:start position:0% +atom yeah calcium likes to lose both of +those + + align:start position:0% +those + + + align:start position:0% +those +calcium often because remember they want + + align:start position:0% +calcium often because remember they want + + + align:start position:0% +calcium often because remember they want +to get to that + + align:start position:0% +to get to that + + + align:start position:0% +to get to that +the octet rule they want to reach their + + align:start position:0% +the octet rule they want to reach their + + + align:start position:0% +the octet rule they want to reach their +va + + align:start position:0% +va + + + align:start position:0% +va +they're eight electrons but calcium's + + align:start position:0% +they're eight electrons but calcium's + + + align:start position:0% +they're eight electrons but calcium's +got two what do i do either somebody + + align:start position:0% +got two what do i do either somebody + + + align:start position:0% +got two what do i do either somebody +gives me six + + align:start position:0% +gives me six + + + align:start position:0% +gives me six +not going to happen or i can lose two + + align:start position:0% +not going to happen or i can lose two + + + align:start position:0% +not going to happen or i can lose two +and so what you get is that calcium will + + align:start position:0% +and so what you get is that calcium will + + + align:start position:0% +and so what you get is that calcium will +go you know + + align:start position:0% +go you know + + + align:start position:0% +go you know +to ca2 plus and but fluorine is still + + align:start position:0% +to ca2 plus and but fluorine is still + + + align:start position:0% +to ca2 plus and but fluorine is still +just + + align:start position:0% +just + + + align:start position:0% +just +f minus right from this i know that the + + align:start position:0% +f minus right from this i know that the + + + align:start position:0% +f minus right from this i know that the +balanced stoichiometry + + align:start position:0% +balanced stoichiometry + + + align:start position:0% +balanced stoichiometry +that is to say how many calcium atoms i + + align:start position:0% +that is to say how many calcium atoms i + + + align:start position:0% +that is to say how many calcium atoms i +need + + align:start position:0% +need + + + align:start position:0% +need +to stabilize this whole ionic bond + + align:start position:0% +to stabilize this whole ionic bond + + + align:start position:0% +to stabilize this whole ionic bond +situation + + align:start position:0% +situation + + + align:start position:0% +situation +is going to be two right i gotta go to + + align:start position:0% +is going to be two right i gotta go to + + + align:start position:0% +is going to be two right i gotta go to +calcium + + align:start position:0% +calcium + + + align:start position:0% +calcium +f2 and if i were going to write this as + + align:start position:0% +f2 and if i were going to write this as + + + align:start position:0% +f2 and if i were going to write this as +with emphasizing the ionic bond i might + + align:start position:0% +with emphasizing the ionic bond i might + + + align:start position:0% +with emphasizing the ionic bond i might +put brackets around just so it's really + + align:start position:0% +put brackets around just so it's really + + + align:start position:0% +put brackets around just so it's really +easy to see + + align:start position:0% +easy to see + + + align:start position:0% +easy to see +two plus there's no dots left because + + align:start position:0% +two plus there's no dots left because + + + align:start position:0% +two plus there's no dots left because +now i'm writing it in a way where i've + + align:start position:0% +now i'm writing it in a way where i've + + + align:start position:0% +now i'm writing it in a way where i've +emphasized + + align:start position:0% +emphasized + + + align:start position:0% +emphasized +that because in tight that f took it + + align:start position:0% +that because in tight that f took it + + + align:start position:0% +that because in tight that f took it +it took it and it is minus + + align:start position:0% +it took it and it is minus + + + align:start position:0% +it took it and it is minus +and there's two of them you see + + align:start position:0% +and there's two of them you see + + + align:start position:0% +and there's two of them you see +so that would be like thinking about an + + align:start position:0% +so that would be like thinking about an + + + align:start position:0% +so that would be like thinking about an +ionic bond + + align:start position:0% +ionic bond + + + align:start position:0% +ionic bond +right but from the lewis dot advantage + + align:start position:0% +right but from the lewis dot advantage + + + align:start position:0% +right but from the lewis dot advantage +point where i really + + align:start position:0% +point where i really + + + align:start position:0% +point where i really +see that flooring took the charge + + align:start position:0% +see that flooring took the charge + + + align:start position:0% +see that flooring took the charge +okay okay so i think + + align:start position:0% +okay okay so i think + + + align:start position:0% +okay okay so i think +and you can go further + + align:start position:0% +and you can go further + + + align:start position:0% +and you can go further +you can go further i think we'll stop + + align:start position:0% +you can go further i think we'll stop + + + align:start position:0% +you can go further i think we'll stop +there and on wednesday like i said + + align:start position:0% +there and on wednesday like i said + + + align:start position:0% +there and on wednesday like i said +we're going lewis all the way and we're + + align:start position:0% +we're going lewis all the way and we're + + + align:start position:0% +we're going lewis all the way and we're +doing covalent + + align:start position:0% +doing covalent + + + align:start position:0% +doing covalent +molecules covalent bonds + + align:start position:0% + + + + align:start position:0% + +you \ No newline at end of file diff --git a/LVfIS8pBI6Y.txt b/LVfIS8pBI6Y.txt new file mode 100644 index 0000000000000000000000000000000000000000..fd8a3548404064c82b2981444021afcfcbff2855 --- /dev/null +++ b/LVfIS8pBI6Y.txt @@ -0,0 +1,627 @@ +align:start position:0% + +here is a simple application of the law + + align:start position:0% +here is a simple application of the law + + + align:start position:0% +here is a simple application of the law +of iterated expectations we revisit the + + align:start position:0% +of iterated expectations we revisit the + + + align:start position:0% +of iterated expectations we revisit the +stick breaking example which we have + + align:start position:0% +stick breaking example which we have + + + align:start position:0% +stick breaking example which we have +seen sometime in the past so in this + + align:start position:0% +seen sometime in the past so in this + + + align:start position:0% +seen sometime in the past so in this +example we start with a stick that has a + + align:start position:0% +example we start with a stick that has a + + + align:start position:0% +example we start with a stick that has a +certain length and which we break at the + + align:start position:0% +certain length and which we break at the + + + align:start position:0% +certain length and which we break at the +point that chosen uniformly at random + + align:start position:0% +point that chosen uniformly at random + + + align:start position:0% +point that chosen uniformly at random +throughout the length of the stick and + + align:start position:0% +throughout the length of the stick and + + + align:start position:0% +throughout the length of the stick and +we call the point at which we cut the + + align:start position:0% +we call the point at which we cut the + + + align:start position:0% +we call the point at which we cut the +stick Capital y so the random variable Y + + align:start position:0% +stick Capital y so the random variable Y + + + align:start position:0% +stick Capital y so the random variable Y +has a uniform distribution on the + + align:start position:0% +has a uniform distribution on the + + + align:start position:0% +has a uniform distribution on the +interval from zero to L and is described + + align:start position:0% +interval from zero to L and is described + + + align:start position:0% +interval from zero to L and is described +by this particular PDF then we take the + + align:start position:0% +by this particular PDF then we take the + + + align:start position:0% +by this particular PDF then we take the +piece of the stick that's left and we + + align:start position:0% +piece of the stick that's left and we + + + align:start position:0% +piece of the stick that's left and we +break it at a point that's chosen + + align:start position:0% +break it at a point that's chosen + + + align:start position:0% +break it at a point that's chosen +uniformly over the length of the stick + + align:start position:0% +uniformly over the length of the stick + + + align:start position:0% +uniformly over the length of the stick +that's left so the stick that was left + + align:start position:0% +that's left so the stick that was left + + + align:start position:0% +that's left so the stick that was left +has a length Y and the place at which we + + align:start position:0% +has a length Y and the place at which we + + + align:start position:0% +has a length Y and the place at which we +cut it X is chosen uniformly over that + + align:start position:0% +cut it X is chosen uniformly over that + + + align:start position:0% +cut it X is chosen uniformly over that +interval so in particular X or rather + + align:start position:0% +interval so in particular X or rather + + + align:start position:0% +interval so in particular X or rather +the conditional distribution of x given + + align:start position:0% +the conditional distribution of x given + + + align:start position:0% +the conditional distribution of x given +Y is uniform on that interval so in this + + align:start position:0% +Y is uniform on that interval so in this + + + align:start position:0% +Y is uniform on that interval so in this +example what is the expected value of X + + align:start position:0% +example what is the expected value of X + + + align:start position:0% +example what is the expected value of X +if I tell you the value of y well given + + align:start position:0% +if I tell you the value of y well given + + + align:start position:0% +if I tell you the value of y well given +the value of y the random variable X is + + align:start position:0% +the value of y the random variable X is + + + align:start position:0% +the value of y the random variable X is +uniform on that range so the expected + + align:start position:0% +uniform on that range so the expected + + + align:start position:0% +uniform on that range so the expected +value is going to be at the midpoint and + + align:start position:0% +value is going to be at the midpoint and + + + align:start position:0% +value is going to be at the midpoint and +is equal to Y over 2 this is an equality + + align:start position:0% +is equal to Y over 2 this is an equality + + + align:start position:0% +is equal to Y over 2 this is an equality +between numbers for any particular + + align:start position:0% +between numbers for any particular + + + align:start position:0% +between numbers for any particular +number little why we have this equality + + align:start position:0% +number little why we have this equality + + + align:start position:0% +number little why we have this equality +now let us convert this concrete + + align:start position:0% +now let us convert this concrete + + + align:start position:0% +now let us convert this concrete +equality between numbers to a more + + align:start position:0% +equality between numbers to a more + + + align:start position:0% +equality between numbers to a more +abstract equality between random + + align:start position:0% +abstract equality between random + + + align:start position:0% +abstract equality between random +variables this object is a random + + align:start position:0% +variables this object is a random + + + align:start position:0% +variables this object is a random +variable that takes this value whenever + + align:start position:0% +variable that takes this value whenever + + + align:start position:0% +variable that takes this value whenever +Capital y is little Y so this is an + + align:start position:0% +Capital y is little Y so this is an + + + align:start position:0% +Capital y is little Y so this is an +object that takes the value little Y + + align:start position:0% +object that takes the value little Y + + + align:start position:0% +object that takes the value little Y +over 2 whenever the random variable + + align:start position:0% +over 2 whenever the random variable + + + align:start position:0% +over 2 whenever the random variable +capital Y happens to be little Y but + + align:start position:0% +capital Y happens to be little Y but + + + align:start position:0% +capital Y happens to be little Y but +that's the same as the random variable + + align:start position:0% +that's the same as the random variable + + + align:start position:0% +that's the same as the random variable +capital y over 2 this is a random + + align:start position:0% +capital y over 2 this is a random + + + align:start position:0% +capital y over 2 this is a random +variable that takes this value whenever + + align:start position:0% +variable that takes this value whenever + + + align:start position:0% +variable that takes this value whenever +capital y happens to be the same as + + align:start position:0% +capital y happens to be the same as + + + align:start position:0% +capital y happens to be the same as +little Y so the conditional expectation + + align:start position:0% +little Y so the conditional expectation + + + align:start position:0% +little Y so the conditional expectation +the abstract conditional expectation is + + align:start position:0% +the abstract conditional expectation is + + + align:start position:0% +the abstract conditional expectation is +a random variable + + align:start position:0% +a random variable + + + align:start position:0% +a random variable +because its value is determined by the + + align:start position:0% +because its value is determined by the + + + align:start position:0% +because its value is determined by the +random variable Capital y and it is this + + align:start position:0% +random variable Capital y and it is this + + + align:start position:0% +random variable Capital y and it is this +particular function of the random + + align:start position:0% +particular function of the random + + + align:start position:0% +particular function of the random +variable Capital y and now we can + + align:start position:0% +variable Capital y and now we can + + + align:start position:0% +variable Capital y and now we can +proceed and calculate the expected value + + align:start position:0% +proceed and calculate the expected value + + + align:start position:0% +proceed and calculate the expected value +of X using the law of iterated + + align:start position:0% +of X using the law of iterated + + + align:start position:0% +of X using the law of iterated +expectations the law of iterated + + align:start position:0% +expectations the law of iterated + + + align:start position:0% +expectations the law of iterated +expectations takes this form we have + + align:start position:0% +expectations takes this form we have + + + align:start position:0% +expectations takes this form we have +already calculated what this random + + align:start position:0% +already calculated what this random + + + align:start position:0% +already calculated what this random +variable is it is the random variable + + align:start position:0% +variable is it is the random variable + + + align:start position:0% +variable is it is the random variable +that's equal to Y over 2 so this is the + + align:start position:0% +that's equal to Y over 2 so this is the + + + align:start position:0% +that's equal to Y over 2 so this is the +same as 1/2 the expected value of Y and + + align:start position:0% +same as 1/2 the expected value of Y and + + + align:start position:0% +same as 1/2 the expected value of Y and +since Y is uniform in the range from 0 + + align:start position:0% +since Y is uniform in the range from 0 + + + align:start position:0% +since Y is uniform in the range from 0 +to 12 the expected value of y is equal + + align:start position:0% +to 12 the expected value of y is equal + + + align:start position:0% +to 12 the expected value of y is equal +to L over 2 which gives us an answer of + + align:start position:0% +to L over 2 which gives us an answer of + + + align:start position:0% +to L over 2 which gives us an answer of +L over 4 this is the same as the answer + + align:start position:0% +L over 4 this is the same as the answer + + + align:start position:0% +L over 4 this is the same as the answer +that we got in the past where we + + align:start position:0% +that we got in the past where we + + + align:start position:0% +that we got in the past where we +actually found it using the total + + align:start position:0% +actually found it using the total + + + align:start position:0% +actually found it using the total +expectation theorem the calculations + + align:start position:0% +expectation theorem the calculations + + + align:start position:0% +expectation theorem the calculations +were exactly the same as what went on + + align:start position:0% +were exactly the same as what went on + + + align:start position:0% +were exactly the same as what went on +here except that here we carry out the + + align:start position:0% +here except that here we carry out the + + + align:start position:0% +here except that here we carry out the +calculation in a more abstract form and + + align:start position:0% +calculation in a more abstract form and + + + align:start position:0% +calculation in a more abstract form and +what is important to appreciate from + + align:start position:0% +what is important to appreciate from + + + align:start position:0% +what is important to appreciate from +this example is the distinction between + + align:start position:0% +this example is the distinction between + + + align:start position:0% +this example is the distinction between +these two lines this is an equality + + align:start position:0% +these two lines this is an equality + + + align:start position:0% +these two lines this is an equality +between numbers which is true for any + + align:start position:0% +between numbers which is true for any + + + align:start position:0% +between numbers which is true for any +specific little Y who are as this is an + + align:start position:0% +specific little Y who are as this is an + + + align:start position:0% +specific little Y who are as this is an +equality between random variables this + + align:start position:0% +equality between random variables this + + + align:start position:0% +equality between random variables this +quantity is random and this quantity is + + align:start position:0% +quantity is random and this quantity is + + + align:start position:0% +quantity is random and this quantity is +also random meaning that their values + + align:start position:0% +also random meaning that their values + + + align:start position:0% +also random meaning that their values +are not known until the experiment is + + align:start position:0% +are not known until the experiment is + + + align:start position:0% +are not known until the experiment is +carried out and the specific value of + + align:start position:0% +carried out and the specific value of + + + align:start position:0% +carried out and the specific value of +capital y is realized \ No newline at end of file diff --git a/LhPZwdhutgU.txt b/LhPZwdhutgU.txt new file mode 100644 index 0000000000000000000000000000000000000000..ac046d323d5e64ccb3f7126bb1c5cc7230b34f7e --- /dev/null +++ b/LhPZwdhutgU.txt @@ -0,0 +1,261 @@ +PROFESSOR: Hello. + +I'm Ian Hutchinson, and the +purpose of this short video + +is to give you illustration +of how to use Octave. + +I'm certainly not an +expert at [? Octave, ?] + +which is an open source +equivalent of MATLAB, + +but that's part of +the demonstration. + +Here's someone who's +not an expert who + +can use this routine +for carrying out + +the kinds of exercises +that we want to do. + +So I'm going to delete my +picture from the screen + +now, and just show you +the rest of the screen. + +Here I am in a directory. + +I'm going to start a new file. + +It's going to be called fitting. + +Let's say, fitting.m, +is the correct extension + +for a MATLAB or Octave file. + +And I've opened Emax, and +I'm ready to get started. + +Actually, I'm going to +run Octave simultaneously + +in the adjacent window. + +I run Octave here. + +So now I'm in a situation +where I, essentially, + +have my own IDE, integrated +development environment. + +It's not quite the +same as you would + +have if you're +running MATLAB itself, + +but it's pretty similar. + +What I'm going to do now is +develop this fitting program. + +I'm going to start +with some parameters. + +Let's, first of all, +define the number + +of points I'm going to fit. + +Let's make it a small number, +so that it's kind of manageable. + +And now, let's generate +some x and y values. + +I can set x to be +equal to an array. + +It might be an array +with six points. + +And I'm going to make it +be run from 1 to endpoints. + +And so I do that by saying +x is equal to 1 colon + +endpoints like this. + +I can save this file-- +it's called fitting-- + +and then I can run it in +Octave by just typing fitting. + +If I do that, what +you see happens is, + +it tells me that endpoints is 6. + +Tells me that x is +1, 2, 3, 4, 5, and 6. + +Actually, I don't want +it to run from 1 to 6. + +I want it to run +from, essentially, + +a small value up to 1. + +So let's divide +it by end points. + +And I can save that file +again, run it again, + +and now, of course, +my screen shows + +that it runs from 1/6 up to 1. + +This is, of course, +a row vector. + +It's preferable that I +have a column vector. + +I can transform a row +vector into a column vector + +by taking its transpose. + +In MATLAB or Octave, +transpose is prime. + +So I can say, +transpose the numbers 1 + +through 6 into a column vector +and then divide by endpoints. + +And if I do that +and save the file, + +then I see I've turned +it into a column vector. + +Let me now make a y variable. + +y, I'm going to make +equal to x, let's say. + +That would just give +me a straight line, + +if I made it nothing but x. + +Then I'll add to it +some small fraction-- + +let's say, 1/10th-- not 0.1 +times the sine of, let us say, + +10 x. + +I can save that file. + +I can run it again. + +And it tells me, +here's x and here's y. + +That's given me a start. + +Actually, it's a +bit inconvenient + +to see it in quite those terms. + +So let's actually +try to plot it. + +So I can say plot x y. + +Save that and run it. + +And lo and behold, +it brings up a plot. + +The labeling is +rather too small, + +but that's kind of built +into the rather poor graphics + +in Octave and MATLAB, +for that matter. + +That can be fixed in ways +that I'll go into later, + +but we won't worry about it now. + +This is a line plot, which +is a little bit annoying. + +So let's change that plot. + +I'll put the figure over here. + +I'll change that +plot by telling it + +that it's going to have +points, and those points + +are going to have the +form of a plus sign. + +So let's save that +and run it again. + +And Lo and behold, it's changed +it to a plot with points. + +Again, the markers are +rather unpleasantly small. + +I can actually change that +if I want by telling it + +a string marker size. + +Making that size larger than +it would be-- let's say, 20-- + +and running it again. + +And lo and behold, +the points are bigger. + +So we've started, and +we've made, some data. + +And we've used parameters. + +And in our next +video, we'll move on + +to finding out how to +proceed on that basis. \ No newline at end of file diff --git a/Lq6Os-qABK4.txt b/Lq6Os-qABK4.txt new file mode 100644 index 0000000000000000000000000000000000000000..09c511f8b36aed63a374f0fe7262c7834293fa06 --- /dev/null +++ b/Lq6Os-qABK4.txt @@ -0,0 +1,1123 @@ +align:start position:0% + +welcome to lab four the spectrometer lab + + align:start position:0% +welcome to lab four the spectrometer lab + + + align:start position:0% +welcome to lab four the spectrometer lab +in this lab you will learn some basic + + align:start position:0% +in this lab you will learn some basic + + + align:start position:0% +in this lab you will learn some basic +concepts in Optics and + + align:start position:0% +concepts in Optics and + + + align:start position:0% +concepts in Optics and +photonics you will also use a simple + + align:start position:0% +photonics you will also use a simple + + + align:start position:0% +photonics you will also use a simple +spectrometer setup to characterize a die + + align:start position:0% +spectrometer setup to characterize a die + + + align:start position:0% +spectrometer setup to characterize a die +called arthin extra + + align:start position:0% + + + + align:start position:0% + +bluish let's begin with the preab + + align:start position:0% +bluish let's begin with the preab + + + align:start position:0% +bluish let's begin with the preab +building a fiber coupled LED light + + align:start position:0% + + + + align:start position:0% + +the components of the preab + + align:start position:0% +the components of the preab + + + align:start position:0% +the components of the preab +include a super bright white light + + align:start position:0% + + + + align:start position:0% + +LED a 200 Ohm + + align:start position:0% +LED a 200 Ohm + + + align:start position:0% +LED a 200 Ohm +resistor a battery strap and a 9vt + + align:start position:0% +resistor a battery strap and a 9vt + + + align:start position:0% +resistor a battery strap and a 9vt +battery a piece of multimode + + align:start position:0% +battery a piece of multimode + + + align:start position:0% +battery a piece of multimode +fiber some + + align:start position:0% +fiber some + + + align:start position:0% +fiber some +sandpaper epoxy or glue and a stick for + + align:start position:0% +sandpaper epoxy or glue and a stick for + + + align:start position:0% +sandpaper epoxy or glue and a stick for +application + + align:start position:0% + + + + align:start position:0% + +you will need to sand away the plastic + + align:start position:0% +you will need to sand away the plastic + + + align:start position:0% +you will need to sand away the plastic +in the front of the LED to make better + + align:start position:0% +in the front of the LED to make better + + + align:start position:0% +in the front of the LED to make better +coupling with the fiber start with the + + align:start position:0% +coupling with the fiber start with the + + + align:start position:0% +coupling with the fiber start with the +rough sandpaper and use the finer + + align:start position:0% +rough sandpaper and use the finer + + + align:start position:0% +rough sandpaper and use the finer +sandpaper later you may sand close to + + align:start position:0% +sandpaper later you may sand close to + + + align:start position:0% +sandpaper later you may sand close to +the bond wire but make sure not to break + + align:start position:0% + + + + align:start position:0% + +it + + align:start position:0% + + + + align:start position:0% + +e e + + align:start position:0% + + + + align:start position:0% + +in the first part of the lab you will be + + align:start position:0% +in the first part of the lab you will be + + + align:start position:0% +in the first part of the lab you will be +observing the fernel coefficients + + align:start position:0% +observing the fernel coefficients + + + align:start position:0% +observing the fernel coefficients +you will measure Fel Reflections from a + + align:start position:0% +you will measure Fel Reflections from a + + + align:start position:0% +you will measure Fel Reflections from a +semicircular acrylic + + align:start position:0% +semicircular acrylic + + + align:start position:0% +semicircular acrylic +prism here's the setup as viewed from + + align:start position:0% +prism here's the setup as viewed from + + + align:start position:0% +prism here's the setup as viewed from +the top you will use a red diode laser a + + align:start position:0% +the top you will use a red diode laser a + + + align:start position:0% +the top you will use a red diode laser a +linear + + align:start position:0% +linear + + + align:start position:0% +linear +polarizer the acrylic prism mounted on a + + align:start position:0% +polarizer the acrylic prism mounted on a + + + align:start position:0% +polarizer the acrylic prism mounted on a +rotational + + align:start position:0% + + + + align:start position:0% + +stage and a high sensitivity power meter + + align:start position:0% + + + + align:start position:0% + +Begin by characterizing the + + align:start position:0% +Begin by characterizing the + + + align:start position:0% +Begin by characterizing the +polarizer you can understand the + + align:start position:0% +polarizer you can understand the + + + align:start position:0% +polarizer you can understand the +direction of the polarizer by looking at + + align:start position:0% +direction of the polarizer by looking at + + + align:start position:0% +direction of the polarizer by looking at +how it attenuates light reflected from a + + align:start position:0% +how it attenuates light reflected from a + + + align:start position:0% +how it attenuates light reflected from a +flat surface + + align:start position:0% + + + + align:start position:0% + +set the polarizer to pass the TM + + align:start position:0% +set the polarizer to pass the TM + + + align:start position:0% +set the polarizer to pass the TM +polarization align the back reflected + + align:start position:0% +polarization align the back reflected + + + align:start position:0% +polarization align the back reflected +beam toward the incoming Direction this + + align:start position:0% +beam toward the incoming Direction this + + + align:start position:0% +beam toward the incoming Direction this +will calibrate 0° or normal + + align:start position:0% +will calibrate 0° or normal + + + align:start position:0% +will calibrate 0° or normal +incidents now measure the incident + + align:start position:0% + + + + align:start position:0% + +power change the angle of incidence by + + align:start position:0% +power change the angle of incidence by + + + align:start position:0% +power change the angle of incidence by +rotating the stage and measure the + + align:start position:0% +rotating the stage and measure the + + + align:start position:0% +rotating the stage and measure the +reflected Power Note the critical angle + + align:start position:0% +reflected Power Note the critical angle + + + align:start position:0% +reflected Power Note the critical angle +at which the transmitted power goes to + + align:start position:0% +at which the transmitted power goes to + + + align:start position:0% +at which the transmitted power goes to +zero for the TM polarization there is + + align:start position:0% +zero for the TM polarization there is + + + align:start position:0% +zero for the TM polarization there is +also a Brewster angle at which the + + align:start position:0% +also a Brewster angle at which the + + + align:start position:0% +also a Brewster angle at which the +reflected power goes to + + align:start position:0% + + + + align:start position:0% + +zero + + align:start position:0% + + + + align:start position:0% + +e + + align:start position:0% + + + + align:start position:0% + +e e + + align:start position:0% + + + + align:start position:0% + +now use the te polarization and make the + + align:start position:0% +now use the te polarization and make the + + + align:start position:0% +now use the te polarization and make the +same set of + + align:start position:0% + + + + align:start position:0% + +measurements + + align:start position:0% + + + + align:start position:0% + +e + + align:start position:0% + + + + align:start position:0% + +e e + + align:start position:0% + + + + align:start position:0% + +now you will observe the index contrast + + align:start position:0% +now you will observe the index contrast + + + align:start position:0% +now you will observe the index contrast +in the + + align:start position:0% + + + + align:start position:0% + +fiber using the LED coupled fiber you + + align:start position:0% +fiber using the LED coupled fiber you + + + align:start position:0% +fiber using the LED coupled fiber you +made in the preab the num numerical + + align:start position:0% +made in the preab the num numerical + + + align:start position:0% +made in the preab the num numerical +aperture is easily found by observing + + align:start position:0% +aperture is easily found by observing + + + align:start position:0% +aperture is easily found by observing +the angle of the output light that's + + align:start position:0% +the angle of the output light that's + + + align:start position:0% +the angle of the output light that's +projected on a + + align:start position:0% + + + + align:start position:0% + +protractor the refractive index of the + + align:start position:0% +protractor the refractive index of the + + + align:start position:0% +protractor the refractive index of the +fiber core is given in the handout the + + align:start position:0% +fiber core is given in the handout the + + + align:start position:0% +fiber core is given in the handout the +numerical aperture formula allows you to + + align:start position:0% +numerical aperture formula allows you to + + + align:start position:0% +numerical aperture formula allows you to +easily calculate the refractive index + + align:start position:0% +easily calculate the refractive index + + + align:start position:0% +easily calculate the refractive index +contrast + + align:start position:0% + + + + align:start position:0% + +in the next section of the lab you will + + align:start position:0% +in the next section of the lab you will + + + align:start position:0% +in the next section of the lab you will +be working with a liquid core wave guide + + align:start position:0% +be working with a liquid core wave guide + + + align:start position:0% +be working with a liquid core wave guide +filled with ethylene + + align:start position:0% +filled with ethylene + + + align:start position:0% +filled with ethylene +glycol make sure you're wearing gloves + + align:start position:0% +glycol make sure you're wearing gloves + + + align:start position:0% +glycol make sure you're wearing gloves +for this part of the + + align:start position:0% +for this part of the + + + align:start position:0% +for this part of the +experiment start with a length of Teflon + + align:start position:0% +experiment start with a length of Teflon + + + align:start position:0% +experiment start with a length of Teflon +tubing of about 100 mm length + + align:start position:0% + + + + align:start position:0% + +extract some of the ethylene glycol + + align:start position:0% +extract some of the ethylene glycol + + + align:start position:0% +extract some of the ethylene glycol +using a clean + + align:start position:0% + + + + align:start position:0% + +syringe use the syringe to carefully + + align:start position:0% +syringe use the syringe to carefully + + + align:start position:0% +syringe use the syringe to carefully +fill the Teflon tubing making sure there + + align:start position:0% +fill the Teflon tubing making sure there + + + align:start position:0% +fill the Teflon tubing making sure there +are no + + align:start position:0% +are no + + + align:start position:0% +are no +bubbles it's ideal to have a small + + align:start position:0% +bubbles it's ideal to have a small + + + align:start position:0% +bubbles it's ideal to have a small +droplet at the end of the tubing + + align:start position:0% + + + + align:start position:0% + +now carefully place the wave guide flush + + align:start position:0% +now carefully place the wave guide flush + + + align:start position:0% +now carefully place the wave guide flush +against the piece of glass glued to a + + align:start position:0% +against the piece of glass glued to a + + + align:start position:0% +against the piece of glass glued to a +fiber VG Grove + + align:start position:0% +fiber VG Grove + + + align:start position:0% +fiber VG Grove +holder this effectively seals the end of + + align:start position:0% +holder this effectively seals the end of + + + align:start position:0% +holder this effectively seals the end of +the wave guide + + align:start position:0% + + + + align:start position:0% + +couple the LED coupled fiber into the + + align:start position:0% +couple the LED coupled fiber into the + + + align:start position:0% +couple the LED coupled fiber into the +end of the wave guide by inserting it + + align:start position:0% +end of the wave guide by inserting it + + + align:start position:0% +end of the wave guide by inserting it +into the Teflon tube + + align:start position:0% + + + + align:start position:0% + +measure again the numerical aperture by + + align:start position:0% +measure again the numerical aperture by + + + align:start position:0% +measure again the numerical aperture by +observing the Divergence angle using a + + align:start position:0% +observing the Divergence angle using a + + + align:start position:0% +observing the Divergence angle using a +protractor because the index of the + + align:start position:0% +protractor because the index of the + + + align:start position:0% +protractor because the index of the +Teflon tubing is known this will allow + + align:start position:0% +Teflon tubing is known this will allow + + + align:start position:0% +Teflon tubing is known this will allow +you to calculate the index of ethylene + + align:start position:0% + + + + align:start position:0% + +glycol the final inlab component is an + + align:start position:0% +glycol the final inlab component is an + + + align:start position:0% +glycol the final inlab component is an +experiment using a homebuilt + + align:start position:0% +experiment using a homebuilt + + + align:start position:0% +experiment using a homebuilt +spectrometer setup construct the + + align:start position:0% +spectrometer setup construct the + + + align:start position:0% +spectrometer setup construct the +spectrometer setup according to the + + align:start position:0% +spectrometer setup according to the + + + align:start position:0% +spectrometer setup according to the +drawing in the lab + + align:start position:0% +drawing in the lab + + + align:start position:0% +drawing in the lab +handout the light source will be the + + align:start position:0% +handout the light source will be the + + + align:start position:0% +handout the light source will be the +fiber coupled liquid core wave guide you + + align:start position:0% +fiber coupled liquid core wave guide you + + + align:start position:0% +fiber coupled liquid core wave guide you +just + + align:start position:0% +just + + + align:start position:0% +just +made set up a black screen with an X to + + align:start position:0% +made set up a black screen with an X to + + + align:start position:0% +made set up a black screen with an X to +focus the + + align:start position:0% + + + + align:start position:0% + +camera a digital + + align:start position:0% +camera a digital + + + align:start position:0% +camera a digital +camera a thin transmitting + + align:start position:0% +camera a thin transmitting + + + align:start position:0% +camera a thin transmitting +grading a flat mounting + + align:start position:0% +grading a flat mounting + + + align:start position:0% +grading a flat mounting +plate and four vials of ithin extra + + align:start position:0% +plate and four vials of ithin extra + + + align:start position:0% +plate and four vials of ithin extra +bluish at different + + align:start position:0% +bluish at different + + + align:start position:0% +bluish at different +concentrations note that V 4 is just + + align:start position:0% +concentrations note that V 4 is just + + + align:start position:0% +concentrations note that V 4 is just +water and used for + + align:start position:0% + + + + align:start position:0% + +calibration e + + align:start position:0% + + + + align:start position:0% + +once the focus of the camera and + + align:start position:0% +once the focus of the camera and + + + align:start position:0% +once the focus of the camera and +position of all components are optimized + + align:start position:0% +position of all components are optimized + + + align:start position:0% +position of all components are optimized +fix them to the table and do not move + + align:start position:0% +fix them to the table and do not move + + + align:start position:0% +fix them to the table and do not move +them for the rest of the + + align:start position:0% +them for the rest of the + + + align:start position:0% +them for the rest of the +experiment the camera should see a + + align:start position:0% +experiment the camera should see a + + + align:start position:0% +experiment the camera should see a +spectrum at the image plane of the black + + align:start position:0% + + + + align:start position:0% + +screen e + + align:start position:0% + + + + align:start position:0% + +first remove the LED coupled fiber and + + align:start position:0% +first remove the LED coupled fiber and + + + align:start position:0% +first remove the LED coupled fiber and +insert instead a plain piece of fiber + + align:start position:0% +insert instead a plain piece of fiber + + + align:start position:0% +insert instead a plain piece of fiber +into the wave guide + + align:start position:0% + + + + align:start position:0% + +calibrate the spectrometer by taking + + align:start position:0% +calibrate the spectrometer by taking + + + align:start position:0% +calibrate the spectrometer by taking +data for a green laser at 532 nanom and + + align:start position:0% +data for a green laser at 532 nanom and + + + align:start position:0% +data for a green laser at 532 nanom and +a red laser at around 650 nanom + + align:start position:0% + + + + align:start position:0% + +replace the LED cuple fiber once you're + + align:start position:0% +replace the LED cuple fiber once you're + + + align:start position:0% +replace the LED cuple fiber once you're +finished with the + + align:start position:0% +finished with the + + + align:start position:0% +finished with the +calibration Mount each D concentration + + align:start position:0% +calibration Mount each D concentration + + + align:start position:0% +calibration Mount each D concentration +in front of the light source and take + + align:start position:0% +in front of the light source and take + + + align:start position:0% +in front of the light source and take +the + + align:start position:0% +the + + + align:start position:0% +the +Spectrum make sure to position the + + align:start position:0% +Spectrum make sure to position the + + + align:start position:0% +Spectrum make sure to position the +cuvette so the propagation thickness is + + align:start position:0% +cuvette so the propagation thickness is + + + align:start position:0% +cuvette so the propagation thickness is +1 cm long you will calculate the + + align:start position:0% +1 cm long you will calculate the + + + align:start position:0% +1 cm long you will calculate the +absorption and Molar Extinction + + align:start position:0% +absorption and Molar Extinction + + + align:start position:0% +absorption and Molar Extinction +coefficients in the postlab + + align:start position:0% + + + + align:start position:0% + +analysis + + align:start position:0% + + + + align:start position:0% + +e for \ No newline at end of file diff --git a/MDcAOTaCXHs.txt b/MDcAOTaCXHs.txt new file mode 100644 index 0000000000000000000000000000000000000000..b049a057b8d88f07e0e078c49c91645c5defdcae --- /dev/null +++ b/MDcAOTaCXHs.txt @@ -0,0 +1,4502 @@ +I'm Erik Demaine. + +You can call me Erik. + +This is the web +page for the class. + +You should all go there if you +haven't already, and sign up + +on this sheet if you want +to be on the mailing list. + +Good. + +So, maybe I'll tell you a little +bit what this class about. + +Then I'll tell you about +how the class works, + +and then we'll do more +about what it's about. + +The idea of lecture 1 is +to cover the entire class + +in one lecture. + +Obviously, I will omit +a few of the details + +because we have a +lot to cover, but I + +thought it would +be fun to give you + +a picture what the whole class +is, what the sort of content + +is, so you know whether +you want to be here. + +And my chalk. + +So this class is about geometry. + +It's about folding. + +It's about algorithms. + +In general, we are interested in +the mathematics and algorithms + +behind folding things. + +And also unfolding things, +because that turns out + +to be pretty interesting. + +And the formal term for +things is geometric objects. + +And you think of things +like your arm folds. + +Pieces of paper fold. + +All sorts of things +fold in the world. + +A lot of the-- if there's +any sheet metal objects + +in this room, maybe +some of these parts + +are folded out of sheet. + +I would guess so. + +So folding is everywhere, +and this class + +is all about how that +works mathematically. + +And I'm a theoretical +computer scientist. + +I do algorithms, so my +slant is towards algorithms, + +which is getting computers +to do all this for you. + +How many people here +are computer scientists? + +How many people are-- you've got +to pick one-- mathematicians? + +How many people are +neither of the above? + +Wow, cool. + +It's like not a lot of +mathematicians only, + +but a lot of +computer scientists, + +a lot of everyone else. + +So I'll go around later +maybe and find out + +what your background is. + +You may be interested +less in the mathematics + +and more in the +applications, so let + +me tell you a little +bit about those. + +I have a long list of +applications, some of which + +have been realized, +some of which + +are still in progress +or just ideas. + +Robotics is a big one, +folding robotic arms. + +And I'll show later different +kinds of transforming robots, + +like Transformers or +Terminator 2-style, where + +you want one robot to take on +many different forms, this idea + +of programmable matter, +where you can program + +the geometry of your +object as well as you + +could program the software. + +So next time when you +buy the new iPhone, + +you download the +hardware in addition + +to downloading software. + +That would be the crazy idea. + +That, of course, +doesn't exist yet. + +But it exists in +some simple forms. + +Computer graphics. + +If you're making +Toy Story 4, and you + +want to animate your characters +from one position to another, + +you have some skeleton +which is a foldable object, + +and you'd like to interpolate +between two key frames + +that the animator +draws automatically. + +That's a morphing problem, +and it's a folding morphing + +problem. + +We have mechanics. + +A lot of the early folding +work is in like 17, 1800s, + +and is motivated by +building mechanical linkages + +to do useful things. + +This is back before +electrical computers, + +we had mechanical +computers of sorts. + +Things like you could sign +your name in triplicate + +by just signing once, +and having a linkage that + +made many copies of it. + +I think Jefferson +used such a linkage. + +We have manufacturing, which +is a pretty broad term-- + +things like sheet metal bending. + +Nano manufacturing, I think, +is an exciting context, + +where you can-- we're +really good at building + +flat nano-scale +objects like CPUs. + +And if you could +get them to fold up, + +then you could manufacture +3D nano-scale objects. + +I have optics here, Jason. + +Sure. + +George [INAUDIBLE] group +does some optical devices + +through folding here at MIT. + +Medical is a big one. + +Imagine folding a +stent really small, + +so it can fit through +small blood vessels + +until it gets to where +you want in your body + +and expands-- do +non-intrusive heart surgery. + +Drug delivery is another one. + +You have some object you want +to deliver, your cancer drug, + +so it follows through your body +until it detects the cancer, + +and then it releases +the drug, for example. + +Something we just +started looking at. + +Aero-astro. + +You want to deploy something +out in outer space. + +You've got to get it there +first within the space shuttle. + +So how do you fold +it down small so it + +fits in your space +shuttle, and then expands + +when it gets there? + +Biology. + +Big one. + +I'm interested in +protein folding. + +Proteins are the building block +of all life forms we know, + +and we'd like to +know how they fold. + +I'll show you some +pictures of them later. + +We'll talk more +about it, obviously, + +in the rest of the class. + +And the goal is to use +this mathematics of folding + +to try to figure out what +biology might be doing + +in real life, though that's +still obviously very difficult. + +Sculpture, sort +of an obvious one. + +Designing cooler +origami is possible, + +thanks to mathematics +and algorithms. + +Hopefully Jason agrees. + +Jason Ku is, I guess, the top +origami designer currently + +at MIT. + +That's a safe bet. + +You could make +some broader claim. + +And we'll get him to +give a guest lecture + +on the more artistic +side of origami, + +and I'll talk about the +mathematics-- some of which + +is currently used +in origami design + +today, either implicitly or +explicitly, some of which + +is yet to be used, but hopefully +will make cooler sculpture. + +You could also imagine +building interactive sculpture. + +Interactive buildings' +architecture + +is another big one. + +How many people +here are architects? + +Cool. + +A bunch. + +So I think this is really +exciting and underexploited + +at the moment, +reconfigurable buildings. + +Hoberman is one +example of somebody + +exploring this, getting the +building to fold from one shape + +to another, or getting your +shades to fold from one shape + +to another, all sorts of things. + +That's all I have. + +Maybe there are more. + +You're welcome to tell me. + +But this is somehow +why you might + +care about the mathematics +of folding things. + +And what else do I have? + +Yeah, let me tell you a +little bit about the field. + +It's, in some sense, old. + +There are some problems in +this world of geometric folding + +that go back four +or five centuries. + +And some of those problems +are still unsolved, + +but a lot of the +action in the field + +has been in the +last 12 years or so. + +And it's been really exciting. + +A lot of theorems +have been proved. + +In fact, a lot of +theorems have been + +proved in the context +of previous iterations + +of this class. + +And so I always have +to update things, + +because we keep +getting new results. + +And the idea of this class +is to cover the bleeding + +edge, whatever the +frontiers of what's known, + +and also to push +that edge further. + +So there is an open problem +session, which is optional. + +But if you want to come solve +new problems that haven't been + +solved before, +every week probably + +we'll work on a problem related +to what I cover in class. + +So you know what's +known, and then we + +try to prove what's unknown. + +That's the idea. + +And that's worked +pretty well in the past. + +Let's dive a little +bit into the sort + +of mathematical structures. + +So say geometric objects. + +There are three main +things that we typically + +think about, linkages, pieces +of paper, and polyhedra. + +A linkage is something like +your arm or a robotic arm. + +You have one-dimensional +straight links like bones, + +and hinges that +connect them together. + +And you'd like to know +how that thing can fold. + +So this is like in the graphics +world or mechanical linkage + +world. + +The typical way we +think about linkages + +is that they have rigid bars. + +As opposed to a string, +which is really floppy, + +here you have these rigid, +like maybe metal, parts, + +and you can only +fold at the hinges. + +That's typical +thinking on linkages. + +Makes it interesting. + +And sometimes we also +require no crossing. + +I'm trying to take a physical +thing you have intuition for, + +and write some of the +mathematical constraints. + +No crossing means you +can't intersect yourself. + +Sometimes that's important. + +Sometimes it's not. + +In a lot of the +mechanical linkage world + +you can have crossing +bars, but just + +because they're in different +planes in real life, + +if you're making a +two-dimensional linkage. + +Paper. + +This is my drawing +of a piece of paper. + +The rules are you +are not allowed + +to stretch the +material, and you're not + +allowed to tear or cut. + +So all you can do is fold. + +And so intuitively +this is saying + +you can't make paper any longer. + +You can't really +make it shorter. + +The only thing you can do +is change its 3D geometry. + +But if you look really closely, +the geometry is the same. + +It has a fixed +intrinsic geometry. + +All the distances on the +surface are staying the same. + +And usually in modern +origami, you're + +not allowed to cut the +paper, because that + +makes things too +easy, basically. + +And I guess also +no crossing here. + +It's a requirement. + +This is a pretty informal +description of paper. + +You can formalize it. + +We will do that at some point. + +But it's pretty intuitive. + +You've all done it before. + +Polyhedron is something +more three-dimensional. + +So here we had one-dimensional +things we were folding. + +Two-dimensional things +we were folding. + +A three-dimensional thing, or at +least a two-dimensional surface + +in three dimensions, +a typical thing + +you might want to do with +a polyhedron is build it. + +And often you want to +build something out + +of flat material, something +like-- you've probably + +made a cube by building a +cross, and then folding it up + +into that thing. + +That's the folding problem. + +The unfolding problem +is, where do I + +cut along this surface +in order to make + +one of these nice unfoldings? + +I think there's one more +cut here in the back. + +If I did it right, that +will unfold into the cross. + +So if I have some complicated +3D shape, what 2D shape + +do I cut out in order to +bend it into that 3D shape? + +That's the unfolding problem. + +There are actually +lots of different kinds + +of polyhedron folding +problems, but here it + +is you want to cut the surface. + +You want one piece-- it's +a little harder to assemble + +multiple pieces-- and you'd like +no overlap in that unfolding. + +Because if, when you +unfold, it overlaps, + +then you can't +actually make it out + +of one piece of sheet material. + +So these are the sorts +of things we study. + +And I think the +plan in the class + +is I will start with paper, +because it's kind of the most + +fun, origami design, +computational origami design. + +And then we'll talk about +linkages and polyhedra. + +And I'll probably jump around +from week to week, just + +to keep it exciting, because +they're all interesting. + +You might each have +your favorite one. + +And so that we can talk +about all of them at once. + +So what kind of +mathematical questions + +would you ask about +these structures? + +Well, there are two main +types I like to characterize. + +On the one hand, we have what +I call foldability questions, + +where you're given some existing +structure like a linkage, + +or a piece of paper with +some creases on it maybe, + +and you'd like to know, +how does that thing fold? + +So I give you some structure, +and you'd like to know, + +does it fold? + +Maybe just does it fold at all? + +Or, in some particular +way, can you + +make it fold into +something interesting? + +Or some notion of interesting? + +I'm going to be generic +here, because there's + +a lot of different +questions obviously. + +And this is in contrast +to a design question, + +where you're given-- what +you start with is a goal. + +Like I want to make a butterfly. + +And then the question is, how +do I fold a piece of paper + +to make that butterfly? + +So here you're given +maybe a crease pattern + +and given some structure. + +You want to see how it folds. + +In design, you're +given the goal and you + +want to figure out +what you should build, + +what folding structure +should I make + +that will achieve this goal? + +So what shapes? + +Shape is one thing +you might want. + +But in general, you have some +property you want to achieve. + +Can you fold it? + +And of course if you +can, how do you do it? + +So this tends-- in +general you could + +think of this as a more +mathematical question, this + +as a more algorithmic question. + +But usually actually +both of them + +are addressed with +algorithms to some extent. + +Of course design +is somehow cooler, + +but often we need to +understand foldability + +before we can solve design. + +But not always. + +It depends. + +And just to give +you like-- I mean + +if you looked at the entire +set of results, the questions + +and answers, that we consider, +and you filter them down, + +there would be three +kinds of things + +that we prove in this class. + +These are the results. + +All the results +in three bullets. + +It could be either +you get universality. + +This is the coolest +kind of result, + +and it's surprisingly common. + +Everything can be folded, for +some notion of everything. + +That's always a challenge. + +And you get an +algorithm to do it. + +So if you say I want +to fold a butterfly, + +you put the butterfly +into the algorithm, + +out come your design +for folding a butterfly. + +That's the ideal picture when +you get a universality result. + +The next best thing +you could hope for + +is a sort of decision +result, which + +is that there's a fast +algorithm that will tell you + +whether something is foldable. + +So we say it +decides foldability. + +So you give it a butterfly. + +It says, oh, that's impossible. + +That's not true. + +But you could imagine that. + +Or maybe you give it a +butterfly, it says yes. + +You give it the +skyline of New York, + +and it says no, you +can't fold that. + +That's not true. + +But if it's not the case +that everything is foldable, + +the next best thing is you +could at least distinguish + +which things are foldable +from which things are not. + +And then, of course, +the worst thing that + +could happen, in some sense, +is you get a hardness results + +which says, there's no good +way to even distinguish + +foldable things from +unfoldable things. + +So I'm going to +say computationally + +intractable to mean generically +that there's no good algorithm + +to solve a problem. + +We're going to be more formal +about that in the future. + +Because different people +have different backgrounds, + +you may know about +competition complexity. + +Many of you don't. + +That's cool. + +We're going to talk +about all that here. + +All right. + +That's the class in a nutshell. + +Totally generic. + +Any questions so far? + +Probably not. + +I thought now I would tell you +a little bit about the class + +structure. + +The main part of the +class are these lectures, + +and attendance is +mandatory for classes, + +because you're not going to +learn it unless you come here. + +You can have exceptions. + +Just email me and +watch the videos later. + +That's one of the fun +features of the videos, + +although the videos are mainly +to reach the world for fun. + +There will be a few problem sets +in this class, not too many. + +And the other main thing that +you turn in is the project. + +So sort of a +project-focused class. + +You will hand in some write up. + +You will give some presentation +in the last few lectures + +of class, if you're taking +the class for credit. + +If you're listening, you +don't have to do this. + +You can, if you want. + +You can do the problem sets. + +Some of them will be fun. + +Hopefully all of +them will be fun. + +None of them will +bee too painful. + +But for people who are +taking the class for credit, + +you have to do a project +and presentation. + +The project could be +about tons of things. + +You could build a sculpture. + +You could come up with a cool +virtual design of something + +amazing that somehow +relates to folding. + +It doesn't have to be direct. + +If you're a coder, you could +implement some algorithm + +we talk about, or make a +beautiful image or animation + +or applet or something. + +If you're more theory, you +could solve an open problem. + +Obviously that's a big win. + +But even trying to solve +an open problem is fine. + +You can talk about how +you failed to solve it, + +in the unhappy +case that happens. + +But if you want to +solve an open problem, + +I would encourage you to come +to the open problem session, + +so we can all solve it together. + +Then you can have +a joint project + +on what we do, but it's totally +unpredictable, of course. + +Even posing an open +problem in this field + +is pretty interesting. + +I know a lot of the +hard open problems. + +I would like to find more of +them, more tractable ones. + +And so if you have some +idea, especially related + +to some application field +that you know a lot about, + +it'd be cool to try +to extract, what + +is the mathematical problem +in a lot of these fields? + +Or you can write a survey. + +That's a typical project. + +You should avoid overlap with-- +I don't actually have it here, + +but the textbook +for this class-- + +you can imagine it being +here-- is Geometric Folding + +Algorithms. + +Here it is. + +Thank you, Jason. + +That's good. + +I ran out of copies. + +Now I have one. + +No, I'll give it back. + +So this is by me and Joe +O'Rourke at Smith College. + +Any questions about +class structure? + +Yeah. + +AUDIENCE: Can projects be +individual? [INAUDIBLE] + +PROFESSOR: Projects +can be with groups. + +I forget whether the +website has a limit + +on the number of people. + +I don't think so. + +But at some point you'll have +to do a project proposal. + +I should mention that also. + +And then I will vet +your project group. + +But I think anything's fine. + +Just when you have +more people, you're + +expected to do a +little more, naturally. + +Other questions? + +Yeah. + +I love collaboration. + +I think I've never written +a paper without a co-author. + +It wasn't a survey paper. + +So collaboration's good. + +All right. + +Doing well. + +So the next thing I +want to do is actually + +dive into actual content. + +This was totally generic. + +And to me, it's useful. + +But maybe to you, +it's less useful. + +This is sort of an organization. + +As we go through, +everything you'll see + +will fit almost always into +one of these three categories. + +The question will fit into +one of these two categories, + +and the answer will fit into +one of these three categories. + +Now let's see what some of +those actual problems, questions + +and answers, are. + +That's the fun part. + +There's so many +cool results here, + +and so many cool open problems. + +I thought I'd tell you a bunch +of the big open problems, too. + +So in today's class, I'm +going to go in order. + +We're going to start with +linkages, and then paper, + +and then polyhedra. + +And I'm going to start with +linkages allowing intersection. + +So magically, bars of the +linkage can overlap each other. + +And then later I'll +talk about linkages, + +which is most interesting +in two dimensions, + +because you can actually build +them in three dimensions. + +And then we'll go to linkages +that do not have intersection. + +So an early +motivation here where + +a lot of this linkage folding +came from originally-- + +this is the 17, 1800s-- is +converting linear motion + +into circular motion. + +Actually, it's really-- +yeah, get it right. + +Linear motion to +circular motion. + +I don't know what order +to cover these things. + +I'll show you a slide. + +My rules are essentially +no words on any slide. + +This is just for +pretty pictures, + +and I'll write +stuff on the board. + +There's this fun book called +How to Draw a Straight + +Line by Kempe in 1877, which +is all about this problem. + +How do I turn a +circular crank and make + +a straight line come +out as a result? + +And the motivation for this +problem is steam engines. + +You have a steam piston, +which is moving something + +up and down along +a straight line. + +And maybe you're building +a locomotive train, + +and you want to turn +a wheel in a circle, + +because wheels are round. + +So how do you convert +this linear motion + +into a circular motion? + +That is How to Draw a Straight +Line, affectionately titled. + +But you can see that one of +the earliest linkages for this + +is called the Watt +parallel motion. + +And we have a little +animation here. + +So the idea is this vertex in +the top left is pinned down. + +This one in the bottom +right is pinned down. + +And then, I think if I move +this around the circle, + +the green guy moves +along that figure eight. + +And there's a limit +to how far it can go. + +So and if you draw it +right, the figure eight + +is almost a straight line. + +So that was mathematics +back in the day. + +No, no one thought +that that was perfect, + +but it was pretty good. + +And that actually led Watt-- +you may have heard of Watt. + +He's a unit. + +And he was very proud +of this invention. + +And he made tons of innovations +in the steam engine world, + +and this was his favorite. + +And, I mean, it changed things. + +But later on-- I mean this +is like 100 years later, + +1864 versus 1764. + +Exactly 100 years later. + +Peaucellier a French guy +in the army, I think, + +came up with this linkage. + +So again, you have two +pinned vertices here. + +This one's moving +around a circle. + +So you just turn +the crank, and look. + +This guy moves +along that red line. + +Perfect. + +Very cool. + +Again it has a limit +how far you can go. + +But it's pretty awesome. + +I mean you could play +with this forever. + +I won't bore you. + +There's this other +guy you may have heard + +of, Kelvin, Lord Kelvin. + +Another unit. + +There's a story about +him playing with one. + +He wouldn't want to +give it up, because he + +was having too much fun just +pushing it back and forth. + +It's like, wow, a straight +line out of a circle. + +So that's pretty cool. + +Making straight lines out +of circles is pretty neat. + +In fact, you could think, +well, what else could I make? + +I can make a straight line. + +That's kind of nice. + +But could I make, I don't +know, some other curve? + +I mean a straight line is +a special kind of curve. + +Maybe I could make this curve. + +That's a nice curve. + +In general, there's +a universality result + +which says there's a +linkage to sign your name. + +That's the cute phrasing. + +So it's a +two-dimensional linkage. + +You turn one circular crank, +and it signs your name. + +The mathematical +version is that you + +trace a piecewise +polynomial curve. + +Or if you're an architect +or graphics person, + +call this a spline. + +Pick your favorite word. + +You can make it all +with one linkage. + +It's pretty crazy, and +not super practical. + +Building this would probably +require thousands of bars. + +But hey, who's counting? + +At least you can get +a universality result. + +This is actually +something that goes back, + +in particular, to the +first time this class was + +taught six years ago. + +We found some better +ways to do, so it's + +known that it could be done. + +And I'll talk about +those ways later on. + +Cool. + +Open problem. + +Not everything is known. + +There's a lot of open +problems here, but one of them + +is, what if you +forbid crossings? + +So these linkages, like the +ones I've been showing here, + +like the Peaucellier linkage, +there's crossing bars. + +And yeah, you could do that, but +what if you forbid crossings? + +It'd be really cool to sign +your name with a linkage that + +doesn't even cross itself. + +That's totally open. + +Getting any kind of +result, positive result, + +maybe not everything, +but at least + +getting some interesting things. + +Even drawing a straight +line, I think, is open. + +Could be a fun +problem to work on. + +All right. + +That's one. + +Let's go over here. + +Let's see, is that the end +of linkages, is crossing? + +No. + +Next question you might +ask is-- so that's + +sort of a design question. + +I was given the goal, which +was to make a straight line + +or sign my name. + +And I wanted to find +the linkage that did it. + +The other question, the +foldability question, + +one of them is rigidity, which +is, does a linkage fold at all? + +I should say a given linkage. + +So for example, I'll +give you three examples. + +Test you out here. + +These are rigid bars +connected by hinges. + +OK, rigid or flexible? + +Rigid, I agree. + +Rigid or flexible. + +Rigid. + +Any other answers? + +Flexible, correct. + +Both are correct. + +In two dimensions, OK, it +depends where you live? + +In two dimensions, this +is rigid no matter what, + +in any dimension. + +But in three dimensions, this is +flexible and in two dimensions, + +it's rigid. + +In three dimensions, +you can pick this guy up + +and it spins around a circle, +out of the board here. + +Or you could pick this guy up. + +It spins around a circle. + +In two dimensions, +though, it's rigid + +because it's really +just two triangles. + +Triangles are rigid +in two dimensions. + +This is a tetrahedron. + +Tetrahedra are rigid +in three dimensions. + +Rigid or flexible? + +Everyone agrees. + +In both dimensions +it is flexible. + +OK, pretty intuitive +for four vertices. + +But you can ask the +mathematical question + +and give you a linkage. + +Is it rigid in 2D? + +Is it rigid in 3D? + +And there are many +versions of this question. + +But the short version, a +short answer, let's say, + +is that distinguishing rigid +from flexible two-dimensional + +linkages is easy. + +There's a good +algorithm to do it. + +It's very powerful, very useful. + +In 3D, we have no idea. + +Very open. + +Tough. + +Very tough problem. + +A lot of people +have been thinking + +about that for decades. + +So that's rigidity. + +I'm just going to touch on +lots of topics very briefly. + +All right. + +Next we go on to, I +guess, one and a half. + +This is linkages +forbidding intersection. + +And this is more +interesting when + +you're talking about 3D +linkages like my arm. + +I really don't want it +to penetrate other bars. + +It's not possible. + +And the first question you +might ask in this world, which + +I guess is a +foldability question, + +sort of a +reconfiguration question, + +let's say I want to fold +my robotic arm from one + +configuration that +I know-- call it + +configuration A-- to some +other configuration, B. + +When is that possible? + +Can I go from A to B? + +Can I go from some other A +prime to some other B prime? + +Sometimes yes, sometimes no. + +It depends. + +Sometimes it's not +foldable at all, + +even when you allow +intersections. + +So this is a pretty +open-ended question. + +In general, it's +computationally intractable. + +If I give you a linkage +and two configurations, + +to decide whether you +can go from A to B + +is, for the +complexity theorists, + +piece space complete. + +Talk about what +that means later. + +Really, really hard +is the short version. + +But a lot of the times you can +think about special linkages. + +There are a lot of +interesting special cases. + +In particular, we like +to think about chains + +like I drew before. + +Also polygons. + +That's a little +messy, but imagine + +those don't self-intersect. + +So this is what I +call an open chain, + +and this is a closed chain. + +In general, these are chains. + +And the other thing I might like +to think about, in particular + +because proteins look kind +of like this, are trees. + +Trees are just linkages +without any cycles in them. + +So those are nice and simple. + +Here I have no cycles, +no cycles, one cycle. + +Easier to think about. + +And sometimes you actually +get a universality result + +that these linkages can +fold from any configuration + +to any configuration. + +And that's especially cool. + +Let me tell you about them. + +Where do I want to go? + +So it depends again what +dimension you live in. + +I'm very flexible in this class. + +You can live in +any dimension you + +want to, and even +fictional ones. + +And you can think about +chains and trees, let's say. + +You could go more +general, but this + +is where most things +have been studied. + +And the answer is, +for chains in 2D + +you get a universality result. + +You can fold from +anything into anything. + +For trees in 2D, you don't. + +There are some trees you can't +get from one configuration + +to another. + +Which ones? + +We don't know. + +But at least you don't +get a universality result. + +In 3D chains you do not +get a universality result. + +And so also for trees, +because that's even harder. + +And for 4D, everything's easy. + +Also in 5D, any +higher dimension. + +Because the intuition here, +at least for this column, + +is you think about tying knots. + +I have a one-dimensional +linkage here. + +Think of it as a +one-dimensional cord. + +It's kind of a kinky cord. + +It has kinks-- not the +other kind of kinky. + +And in two dimensions, +if you draw + +a non-self-intersecting +loop, it's never knotted. + +You can't draw a knot +in two dimensions. + +You can drawn a knot +in three dimensions, + +and you cannot draw a knot +in four dimensions or higher. + +You may not know that +result, but it's true. + +So it matches, but things are +little tricky, even trees. + +If this was a piece +of string, you'd + +be able to always fold this +piece of a tree-shaped piece + +of string into +anything you wanted. + +But it's a little +more complicated. + +Let me show you a locked +tree, I think, is next. + +Yeah. + +For a long time, these were +the only known locked trees. + +These are configurations of tree +linkages that cannot reach some + +other configuration. + +In fact, they can +barely move at all. + +It's less obvious +for some of them. + +But say, in this +top left one, you + +have these little sort of petals +tucked into their armpits, + +I guess, and you can't +get any of those arms + +open unless you had a +lot of room to open it. + +And in order to make +room, you'd have + +to squeeze all the +others really tight. + +And if you draw this +example tight enough, + +also none of the arms can +get compressed very much. + +And so it's locked. + +And this is one of the first +examples actually discovered + +in 1998, and publication +took a while. + +There are a few others, +which you see here. + +This one's kind of +crazy because it + +has only one vertex with +three incident bars. + +Everybody else is like a chain. + +So it's like three chains +joined together at that point, + +and still it is locked. + +And for a long time, +these were the examples + +we would always carry around. + +These are the ones that +appear in the textbook. + +But I thought it would +be neat to see, well, + +are there any simpler examples? + +And last time this class +was offered three years ago, + +we found what is believed +to be the smallest + +locked tree in existence. + +It has 1, 2, 3, 4, 5, 6, 7, +8 bars, if I counted right. + +And it looks curved here, +just to make it easier to see. + +But, in fact, you could +straighten these out + +and it's still locked. + +If you squeeze these +little regions down, + +they'd be very tight. + +So that was with a bunch of +students from this class. + +Cool. + +So that gives you some +idea of this answer. + +Maybe I'll draw you +a picture for chains, + +because it's really simple. + +OK, imagine tying a knot, but +don't actually close the loops. + +And make these end lengths +really, really long. + +We call this the +knitting needles example, + +because the intuition was you +have two long knitting needles, + +and then a very short cord +connecting them in a knot. + +Mathematically, +this is not a knot, + +because if it were string, you +could untie it, no problem. + +But because of these really +long bars, you can't untie it. + +So that's why 3D is hard. + +Or one example of +why 3D is hard. + +It's pretty much +our only example. + +It is the smallest example, and +we can prove things about it. + +But there's a pretty +fascinating open question here, + +I would say, which +is, characterize + +these bad examples. + +Which 3D chains and +which 2D trees have + +locked configurations? + +And all that means is that +there are two configurations, + +A and B, for which you +cannot get from A to B. + +So this is an example. + +Those locked trees +are an example. + +It'd be really fascinating +if you could do this. + +I would guess that this is a +hard problem, but I don't know. + +It's hard to know +whether it's hard. + +It'd be nice to understand +3D chains in particular, + +because they relate-- +and 3D trees. + +Oh, sorry. + +I have more animations. + +I forgot. + +Let me show you some pretty +pictures for this result. + +This was actually my PhD +thesis, way back in 2001. + +And this is a more +modern algorithm + +for solving this problem. + +I give you some +complicated polygon. + +First thing you want +to know is, can you + +unfold it into a +nice convex shape? + +Once you get there, you could +refolded into some other shape + +by playing one of these +motions backwards. + +So that's how you +unfold some teeth. + +Here's one of those tree +examples, but doubled. + +For a while, people thought +that might still be locked, + +but it's not. + +Can do this crazy fivefold +rotationally symmetric motion + +to unfold that thing. + +We're zooming in +and out, so it looks + +like things are getting +bigger and smaller. + +But in fact, each of these bars +is staying the same length, + +and they're never +crossing each other. + +Here's a much more +complicated example. + +This is the first +algorithm that could + +handle examples of this size. + +It's pretty fast. + +That's like it's +going to come back. + +You can do it. + +It's like a spider. + +Spooky. + +I think it has 500 +vertices, and it probably + +took a couple +minutes to compute. + +I'm not computing it live here. + +There's an applet +on the web if you + +want to pick your +favorite polygon + +and run this algorithm on it. + +It doesn't make quite +movies like in this style, + +but it will show +you how it unfolds. + +We call this the tentacle. + +Yeah, so we'll talk about +this algorithm, how it works. + +There's a couple +other algorithms + +for solving this problem. + +It's pretty cool, +and you could imagine + +using this for planning the +motion of a robotic arm in two + +dimensions. + +But in three dimensions, +things are a lot harder. + +We lack good algorithms. + +I would like to study +four dimensions actually. + +There's some pretty +neat questions here, + +but I'm not supposed +to talk about that. + +It's not on my list. + +I've got to move quickly, but +we're doing all right on time. + +What I wanted to show +you was a protein. + +This is a particular +enzyme protein + +called hexokinase, whatever. + +Embarrassing myself. + +It's a particularly +complicated one. + +It is one of a few I could +find a nice free image of. + +But you can see closely, +if you look closely here, + +it's a linkage. + +And this one actually +has lots of cycles. + +But the backbone of a +protein is like a tree, + +and so it fits into +this kind of world. + +Unfortunately it +fits in this world + +of three-dimensional trees, +which are really hard to fold. + +Or three-dimensional +chains, if you really + +just look at the backbone. + +They're a little bit more +complicated than the sorts + +of linkages we're +talking about here, + +but it makes it even harder +to fold things like this. + +But there's something +special about proteins + +that makes them +fold really well. + +That enzyme over there is +in every living organism + +we have ever tested for the +existence of that thing, which + +I assume is everything. + +And yet it's folding. + +It's produced by this +machine-- the Ribosome, + +you probably know about it-- +in a sort of straight state, + +and then it folds into +this shape pretty reliably, + +less than a second, usually +like within nanoseconds. + +So it's really hard to +watch what's happening. + +It's very hot and jiggly, +so it's a little hard + +to see what's actually +going on in the real thing. + +But somehow, these kinds +of barriers to foldability + +don't happen. + +Maybe that's because evolution +found the right things, + +or maybe it's because +protein chains don't really + +look like this. + +They don't have these super +long bars and super short bars. + +If you've ever played with a +chemistry set, all of the bars + +are within a factor of +like 1.5 of each other. + +So there's lots of cool +mathematical questions + +that come out of +protein folding, + +and we will talk +about the ones I know. + +I'd love to find more. + +But the ones I know +I will talk about. + +And that's linkages. + +Let me move on to paper, +unless there are questions. + +All right. + +Let's go over here. + +So we've seen some universality +results, some hardness results. + +I didn't go into them. + +Folding these linkages. + +Let's do that for paper. + +I think first up I +have foldability. + +And then we'll +talk about design. + +So there are lots of +questions in both. + +But for foldability, the +sort of first question people + +like to ask is, which +crease patterns fold flat? + +So a crease pattern +is just a graph + +drawn on a piece of paper. + +So you have some +collection of lines, + +and I think that will fold flat. + +But I'm not going to try to +draw something more complicated, + +but you could imagine doing it. + +I don't know. + +That probably is +not flat foldable. + +It might be. + +It's close. + +But that's the sort of question. + +If you take some +origami and unfold it, + +what kind of +patterns do you get? + +Some flat origami, +something that + +folds into two +dimensions in the end. + +There's some really +nice structure here. + +If I drew it right, this +angle plus this angle + +should equal 180 +degrees, for example. + +And that's true everywhere. + +And there's all sorts +of cool properties. + +But unfortunately, +this is really hard. + +This is NP hard problem. + +You've probably at least +heard of P versus NP. + +Again, I'll define it later. + +But it means probably +there is no good algorithm + +to solve this problem. + +It's really hard +to figure out which + +crease patterns fold flat. + +It's kind of annoying. + +One good news is +that if you just + +have an example like the +original thing I drew, + +which is like this-- so it +has one vertex and a bunch + +of creases emanating out, +that picture we understand. + +So it's easy for +a single vertex. + +That may seem kind of trivial, +but it's actually really useful + +because it lets you understand +the local behavior around one + +vertex. + +If you check that +for every vertex, + +you don't know that the whole +thing folds, but at least + +you know it mostly +folds, at least locally. + +And you can't tell whether +it globally folds correctly, + +because that's NP hard. + +There are so many questions here +like, what about two vertices? + +No one's studied that. + +I think it's polynomial, +but well, it's + +certainly polynomial, +but I think + +you could do it in linear time. + +Anyway, there's lots +of open questions + +there I haven't +even listed here. + +One of the bigger open +questions is a particular kind + +of crease pattern, which you may +have encountered in real life + +refolding your roadmaps. + +The saying goes, the +easiest way to refold + +your road map is differently. + +So suppose you have your road +map, and each of these creases + +is marked. + +I'm not going to mark +all them because it's + +a little messy with +black and white chalk. + +But some of them are marked +mountain, some of them + +are marked valley, meaning +you fold-- this is valley. + +This is mountain. + +So they just have a relative +orientation to each other. + +Suppose you look +carefully at your map. + +You can recover which +way it was folded last, + +hopefully correctly. + +And then you want to find, +does that thing fold flat? + +Sometimes it does, +sometimes it doesn't. + +For two by n maps, we don't +know whether we can even + +detect this with an +efficient algorithm. + +Can I decide whether +this thing folds flat + +using those creases +and those orientations? + +For two by n, it's open. + +For one by n, it's easy. + +Obviously for bigger, +it's also open. + +Two by n is the smallest. + +This is a really +annoying problem. + +Worked on it many times. + +It's very difficult. + +All right, so that's a quick +overview of foldability. + +It's hard, but there are a lot +of interesting special cases + +where we might be +able to solve it. + +Let's move on to design, +which is probably + +where most of the action +is in the origami world, + +in the mathematical +origami world. + +So and there are +tons of results, + +and I had a much +longer list initially, + +but I trimmed just for +brevity down to a few things. + +The central question-- +at least it's + +been considered so far-- in +computational origami design + +is, what shapes can you make? + +You could imagine other +properties than just shape, + +if you want stability +in your folding, + +lots of practical things-- +not much thickness, + +not too many creases, whatever. + +But shape has sort of +been the fun centerpiece. + +And there's an early result +that says universally, + +you can make anything you want. + +And in the +mathematical world, you + +might try to make a polygon. + +Try to make a +silhouette or something. + +You could make a +polyhedron in 3D. + +Maybe you want to wrap a box, +so you want to fold a box, + +or you want to fold a +3D model of a dragon. + +That's all possible. + +And for fun, you can even +make any two-color pattern + +on either of those things. + +So I have a tiny example +here, which is-- yeah, + +it's still alive-- a four +by four checkerboard. + +And it's made from +one square paper. + +It's white on one side +and red on the other. + +So you get some idea of +making two-color patterns. + +This one's pretty easy to fold. + +It even folds itself almost. + +That's great. + +Usually when I give a +class like to high school + +students or something, I say, +could you refold this for me? + +And they're like, oh, no! + +But it actually does it itself. + +It's great. + +Like magic. + +So you could try that at home. + +Just take a square paper. + +It works. + +So this is great. + +Super general. + +This is something actually +my dad and I proved + +with Joe Mitchell +back in '99, I think. + +I don't remember exactly. + +So beginning of modern +computational origami design. + +But the way that we do +this, while algorithmic, + +is completely impractical. + +We'd never want to +use the foldings that + +are designed by this algorithm, +unless you're starting out + +with a big ticker tape of paper. + +Then it's a great method. + +But if you're starting with a +square, the first thing it does + +is fold it down to a +tiny little narrow strip, + +and then wraps the shape. + +And we'll see how that's done. + +It's interesting to +do it mathematically, + +but it's not how you want +to do it practically. + +Good news is-- that used to be +sort of the end of the story. + +But now you can even do +it pretty practically-- + +practically is a +relative term-- using + +something called Origamizer. + +And if you've seen the poster +of this class, you've seen-- + +and if I'm lucky, it's +even the next slide, + +yes it is-- this rabbit-- +bunny, I should say. + +This is the Stanford bunny. + +The original Stanford +bunny is in the top right. + +That's a classic model. + +Everybody in computer graphics +does something with that bunny. + +It has a zillion triangles. + +I don't know offhand how many. + +It's been simplified +here to make + +it feasible to fold to +this mesh of triangles. + +So the input to the algorithm +was this mesh of triangles. + +The output of the algorithm-- +and it's a real program, + +you can go and download +it right now for free-- + +is this crease pattern. + +Now it doesn't look +like a square or paper, + +but if you start with +a square of paper, + +you just fold away +the excess stuff. + +You'll get to a piece +of paper like this. + +And then you just fold along +all those little creases there, + +and eight hours later +you have this bunny. + +This is a real photograph +of a folded bunny + +by Tomohiro Tachi, who +designed this thing. + +He came up with the original +algorithm and computer program. + +In the last few +years, we've been + +proving this algorithm +actually always works. + +We still don't know how to +prove that it's efficient, + +or even what +efficient should mean. + +But in practice it's super good. + +If you look closely, +the white parts + +are the parts of +the paper that you + +need to use in +order to make this. + +They are the triangles +of the surface. + +These grey regions +are the excess. + +And it's pretty small. + +I don't know, maybe 50% of the +area is used in a useful way + +here, which is a lot. + +Whereas this method +over here would use + +like a one millionth +of a percent + +of the paper or something. + +A very tiny amount. + +The Origamizer is +super efficient. + +We don't know how to prove +that it's super efficient, + +but at least we can +prove that it works. + +It will make any 3D +polyhedron you want. + +And in practice, it +seems really good at it. + +Now it's a very different +style from typical origami, + +so this has not yet hit the +sculpture world, let's say. + +But I think it opens the door +to a lot of new possibilities. + +Traditionally +though-- traditionally + +before this Origamizer +or in practice + +today, a much more +commonly used approach + +to computational +origami design is + +something called +the tree method. + +I'm just going to call +it TreeMaker here. + +TreeMaker's the name +of the program that + +implements the tree method, +and it's made by Robert Lang. + +And this is sort of making +stick figures, which + +sounds a little silly. + +But TreeMaker or the +tree method is powerful + +for if I want to make what's +called an origami base, that + +has a lot of limbs in different +places of different lengths-- + +maybe you want to make +something like that. + +I don't know. + +The typical origami base might +look something like this. + +Maybe you want to make a lizard. + +It has a head, some forearms, +some really big hind legs, + +a little tail, and some body. + +You can abstract +this into a tree + +and then say, well can +I fold a piece of paper + +into some shape +whose projection is + +that tree, with all +the right edge links? + +And the answer is yes. + +I mean, you can make +anything, of course. + +But what TreeMaker tries to do +is find the most efficient way + +to make that thing. + +Unfortunately, finding +the most efficient way-- + +like the smallest square +paper, so the most paper + +usage possible to make +something with that projection-- + +finding that is NP complete. + +We just proved that this +year with Robert Lang + +and Sandor Fekete. + +But there's a theory. + +There's a hard problem +you have to solve, + +something related +to disk packing. + +If you solve it, you +find the best way. + +In practice, use some heuristics +which are really good. + +And usually you +find the optimal way + +to make a given stick figure. + +But for super complicated +things, it may not be perfect. + +Now a lot of people use this +method for designing origami. + +I have a slide of cool +origami, just to show you. + +Not all of this uses +the tree method. + +These three designs +by Brian Chan, + +who was an MIT grad student, +graduated last year-- + +these are all designed +partly using the tree method. + +I'm sure they're more +complicated than that. + +But to get the initial structure +of the arms in the right place, + +the legs in the right place, +the head, body segments, + +fingers-- some of +these guys have + +fingers-- all that stuff +is done using tree theory, + +almost certainly not with +TreeMaker, the program. + +Most origami designers do it by +hand, in their head, or drawing + +pictures with a drawing +program, to design out the base. + +Then they fold by +hand everything. + +But still, the math is in there. + +These guys are not yet +mathematically analyzed, + +let's say. + +They're experiments by +[? Garn ?] and Joel Cooper. + +[? Garn ?] is a computer +scientist slash mathematician, + +but he doesn't understand +these yet, and sort of he's + +trying to figure it out. + +So there's a lot of +interesting questions, + +and you get some really +cool sculpture as a result, + +out of this world. + +So this is something +we've also been working on + +with my dad and Robert Lang, +proving that this actually + +works. + +It's been around +for a long time, + +but it turns out to +be really complicated + +to prove that it always works. + +But it looks like it +does, so stay tuned. + +Some time we will +publish that paper. + +It's still in process. + +All right. + +I have some more fun things. + +This is just a random selection. + +There's a ton of work here. + +One of my favorites-- this was +my first result in this field-- + +is the folding cut +problem, theorem, whatever. + +So you start with a rectangle +of paper, and you fold it flat. + +Now you take your +scissors-- I know + +this is blasphemy +for most origamists. + +But I'm not going to +make a lot of cuts. + +I'm just going to make +one complete straight cut. + +I get two pieces in this case, +and then I unfold the pieces + +and see what I get. + +In this case I +get a little swan. + +And the general theorem is you +can make any polygon you want. + +In fact, you can +make one cut and make + +any collection of +polygons you want. + +So like on my website, +you can make the MIT logo + +with all the little rectangles +with one complete straight cut. + +And the outside +shape will have holes + +exactly where you want them. + +And you can download +this, too, if you + +want to impress +all your friends, + +especially recommended +for, like, kids. + +It's a good magic trick. + +In fact, Harry Houdini +used to do this trick + +in the '20s before he +was an escape artist. + +He did general magic. + +Not this trick. + +He made stars. + +And we thought about it, and we +proved you could make anything. + +So that's fun. + +Another universality result. + +It's what got us started. + +And it relates to things +like the tree theory, + +in fact, because what +you're really solving here + +is, how do I take a polygon +and-- if I fold this guy back + +up-- how do I make all +the edges of that polygon + +lie along-- this +guy's not very happy, + +get rid of that-- lie +along a straight line. + +That actually turns out to be +important for origami design. + +A lot of these things-- +an Origamizer-- + +it's all over the place. + +And so this structure +is helpful for solving + +sort of pure origami +problems, not with cutting. + +So what else do I have? + +Curved creases. + +You may not know this, +because most origami + +is straight creases. + +But if you take +a piece of paper, + +you can put a curved +crease into it. + +It's a little hard to do +by hand, but there you go. + +Curved crease. + +Is that allowed? + +What can you make like that? + +It's not too well studied. + +Jeannine Mosely has done some +of the curved crease stuff. + +Early stuff was done +by David Huffman, + +you may know from Huffman codes +in every cell phone, whatever. + +And by Ron Resch. + +That's wrong queuing. + +All right, I'm going +to show that later. + +This are some of the +things that we've made, + +this is my dad and I, +out of curved creases. + +This is kind of a crazy-- it's +like a circular piece of paper, + +but it goes around +twice like a ramp. + +So you make two circles +and then join the ends, + +and you pleat along +concentric circles, + +alternating mountain and valley. + +And you change a few +different parameters, + +and you get these +three different shapes. + +These are in the permanent +collection at MOMA in New York. + +So you can make some really +cool sculpture out of this. + +This is a more +recent piece we did. + +And this is taking just a +regular circular band of paper + +with concentric +circular creases, + +and then taking three of them +and joining them together + +at a few points. + +And then you get +some cool structures. + +These are interesting to us +especially because the paper + +actually does fold itself. + +You put in these +circular creases. + +You just squeeze +a little, and it + +will make these +shapes automatically. + +It's called +self-folding origami. + +And in that spirit, +I will show you + +a different kind of +self-folding origami. + +I think I need to +click this button. + +Which is approach to making +paper that folds itself. + +This is a self-folding sheet. + +It's made of rigid panels +connected by little rubber + +hinges, and there's little +muscles, you could say, + +that are folding +those creases shut. + +By turning on some +electrical signal, + +that thing folds +itself into a boat. + +That same sheet, you can send +it a different electrical signal + +and it will just fold +along these two creases. + +And then there's little +magnets to hold it into place, + +so you can turn off +that electricity now. + +No power. + +Then you send it a third signal, +and it will fold those three + +creases, and you get +a paper airplane. + +No origamist required. + +So the idea here, this is the +programmable matter vision, + +where you could download +hardware in the same way + +you could download software. + +You can make one sheet that +has lots of panels in it, + +enough creases to make +anything you want. + +And then you just push a +button and some of the creases + +turn on. + +Then push a button and +some other creases turn on, + +and it folds into some +complicated origami + +all by itself. + +You could imagine making +this building scale. + +You could imagine making it +nano scale, some scale where + +an origamist can't +do it, or you don't + +have an origamist +to do it for you. + +This would be the +self-refolding, transforming + +robot thing. + +To do it, though, we +needed to prove new theory. + +And this is the world of, call +it, universal hinge patterns. + +And this is the topic of a +master's thesis just finished + +last week, I think, +by [? Viva Vadia ?] + +where-- and maybe +we'll get him to talk + +about it at some point-- +it's one crease pattern. + +In that case we were using +a crease pattern called + +box pleating, where +you take a square grid, + +and then you put alternating +diagonals in those squares. + +Get my alternation going here. + +So that's the so-called +box pleating pattern. + +We proved that that pattern, +if you make it big enough, + +can fold any 3D shape that's +made out of little cubes. + +I think, yeah, so in fact if +you take a sort of n by n sheet, + +you could make about n cubes. + +And in the worst case, +that's the best you can do. + +So that's cool, +because that tells + +you here's one robot you build. + +You just make this sheet +with those creases, + +those rubber creases with +muscles on each of those edges. + +And if you can turn those +edges on and off programmably, + +you could make anything you +want up to some resolution. + +If you want to make a +bunny, you can sort of + +build that bunny our of +little cubes in simulation, + +and then fold that cubefied, +voxillized form of the bunny. + +And then you want to +make something else, + +you unfold it and refold +it all automatically. + +AUDIENCE: This is +like [INAUDIBLE] + +no width of the material? + +PROFESSOR: Yeah, there's a +lot of open questions here. + +This result assumes 0 thickness. + +In fact, every result +I've talked about + +assumes 0 thickness. + +I think there's one theorem +in the literature that + +looks at thickness of paper. + +That's a great open +question, and you really + +see it in something +like that video. + +That just appeared at PNAS, +and the video's online. + +Because in the +airplane, you have + +to fold through multiple layers. + +And that's tricky. + +We get around that right now by +having the creases be a little + +bit stretchy, some rubber. + +But there's a limit, and it's +related to the thickness. + +So yes, some complicated shapes +are not going to work this way. + +I think one thing that +would work really well-- we + +have another result with Jason +Ku, which is folding a maze. + +This is sort of like folding +a shallow terrain in this way, + +so you could make a rat maze +out of a square-- just tracks + +by 50%, and then +you have arbitrary + +undulation in the middle, +which is pretty cool. + +So some of these things +are going to be practical. + +Some are not. + +So there's still interesting +theory questions to ask about. + +I think thickness is +a really good one. + +Other questions? + +Yeah. + +AUDIENCE: [INAUDIBLE] I thought +I heard something about how you + +can't fold a sheet of +paper more than like-- + +PROFESSOR: Yeah, so +that's the one thing. + +The question is, you can't +fold a piece of paper in half 8 + +times, 7 times, whatever the +number is everyone quotes. + +The answer was solved by +someone who was a high school + +student a few years ago. + +What's her name? + +Britney Gallivan. + +And so this is the one paper +that's about thickness, + +and she analyzed-- the issue +is when you fold-- if you have + +a folding that is +1,000 layers thick, + +and you want to +fold in the middle, + +you can't just like cut here +and move it over here and then + +be folded. + +Paper has to actually +turn that corner. + +And the thicker that thing +is, the more length of paper + +it takes to turn that corner. + +And you can compute +how much that + +is if you assume sort of +a circular trajectory, + +and it matches reality. + +So she computed how thin does +a piece of paper need to be, + +or how long does +a piece of paper + +have to be-- it's +that ratio-- in order + +to fold it in half 12 times. + +So she took a piece of +paper that was, I think, + +three-quarters of a mile long, +and folded it in half 12 times. + +And it's like this big +monstrosity when it's done. + +And it follows the +theory exactly. + +So that seems to +be the right model, + +but that's the only +paper that analyzes + +paper folding in that +model, because it's so much + +easier to think +about zero thickness. + +But that is what we should do. + +So that particular +question we understand, + +but everything else is open. + +I'll show you some +pictures of that next time. + +Other questions? + +All right. + +That is paper, and +then I was going + +to show you a little bit +about polyhedra and hinged + +dissections. + +All right. + +Let's go. + +So I mentioned there's a +bunch of different kinds + +of polyhedron folding +and unfolding problems. + +Probably the coolest +one-- because it's + +the oldest problem in +this entire field-- + +is unfolding convex polyhedron +by cutting along the edges. + +We call this edge +unfolding convex polyhedra. + +At the beginning of +class, I showed you + +a cube which you could +unfold into a cross. + +I want that. + +So I was only cutting +along edges of the cube. + +That's this edge unfolding. + +The cube is a convex shape. + +It doesn't have any dents. + +And I got to unfold it with +one piece without overlap. + +Is that always possible? + +We have no idea. + +Can every convex polyhedron +be made in that way? + +We don't know. + +This problem goes back +to Albrecht Durer, + +this guy on the left. + +This is his self-portrait. + +In 1525, he wrote this book +called The Painter's Manual + +in German. + +And he tried this out for +a whole bunch of polyhedra. + +This is the so-called snub +cube, and unfolded in his book. + +And he has page after page +after page of these unfoldings. + +And they're all edge unfoldings. + +Most of them are correct. + +There's a couple small +errors, probably just + +transcription errors. + +And he did this +because he wanted + +to understand these 3D shapes. + +He had to build them. + +How do you build them? + +So he didn't pose this +mathematical question. + +He was not a mathematician. + +But it's sort of implicit +there, and people + +have been thinking about it for +at least decades if not more. + +At least since '65, I think, +was the first formal posing. + +And it's really hard. + +A lot of people +have worked on it. + +We'll talk about it. + +There are some interesting +things that are known. + +I mean the depressing +thing is we + +have no algorithm which +we think will work. + +Every algorithm we've tried +has a counter example. + +Every counter +example we've tried + +has an algorithm +for which it works, + +but they don't match +up, so it's frustrating. + +If you allow +non-convex polyhedra, + +then the answer is no. + +So that's something I did +with a bunch of people + +back in the day. + +This was actually +done in '98, then + +it took forever for the +journal paper to appear. + +This is a polyhedron. + +All the faces are triangles. + +So it's sort of +topologically convex. + +And then if I made the +spike a little shorter, + +it would be a convex polyhedron. + +But this particular embedding-- +these are just two views. + +If you cross your eyes, +it's three dimensions. + +No, I'm just kidding. + +It's not designed for that. + +Just two views of +the same thing. + +And if you cut along the +edges any way you want, + +it will overlap itself +or be multiple pieces. + +And we'll prove +that at some point. + +It's not too hard. + +Yeah, so good. + +That's edge unfolding. + +But there's another +kind of unfolding + +called general unfolding. + +This seems a lot more +interesting to me. + +Edges are sort of artificial. + +What if you let me cut +anywhere on the surface, + +not just at the edges? + +Well, then it turns out, +for convex polyhedra, + +you can do it. + +It's always possible. + +I don't have pictures +of that here, + +but even for some non-convex +polyhedra you could do it. + +For example, this +polyhedron, if you + +let me cut not just at the edges +but anywhere on the surface, + +you can do this crazy thing. + +These are the spikes, and you +cut out a tiny little sliver + +out to the side, +and that lets you + +attach one of those spikes +from one of these witch's hats + +to the wrong side. + +Like you see, this blue guy, the +blue spike-- because this edge + +ends up being +glued over here, we + +can attach the spike with +the little sliver that + +gets opened up here, over +there, and avoid overlap. + +Even if these spikes +are super tall, + +does this go out to +infinity and overlap. + +That's one example. + +Can you do it for every +non-convex polyhedron? + +We don't know. + +I would love to +answer that question. + +The one thing we know or +the big thing that we know + +is so-called +orthogonal polyhedra. + +This is always possible. + +This the same kind of +thing I was talking about. + +You take any 3D shape +made of little cubes-- + +so all the faces are horizontal, +vertical, or the other way-- + +then it's also always possible. + +The current method takes an +exponential number of cuts. + +It's really impractical. + +I think we could +make it practical. + +I think we could generalize +it to everything. + +But those are all +open questions. + +One more picture I +wanted to show you + +is, so here we really want +to keep the shape connected. + +You have to have a +positive area of connection + +between everything. + +If you let that connection +go down to a single point-- + +sort of cheating, this is +called vertex unfolding-- + +and then it's possible for any +surface made out of triangles. + +So it could be +non-convex, anything. + +These happen to be +convex polyhedra. + +It's a little hard to see that +they're three-dimensional, + +but they are. + +You cut them up +into little faces. + +Here I'm only +cutting along edges. + +And I string them +out on a line here. + +This thing will not +overlap, but I'm + +kind of cheating because +the connections are only + +at single points. + +But hey, we'll take a positive +result if we can get it. + +A lot of these problems +are really hard. + +OK, the next thing +I want to talk about + +is the reverse +direction folding. + +So we know-- this is +a video I made back + +when I was a grad +student, a long time ago. + +So we know you can take +a cube, and there's + +a whole bunch of different ways +to just cut along its edges + +and unfold it into one piece. + +And the particular +unfolding I want to consider + +is the cross unfolding, +because that's our favorite. + +So you take this +cross unfolding, + +and ideally don't stutter. + +And you say, well what if +I gave you that polygon? + +What 3D shapes +could it fold into? + +One thing is the +cube, but it can also + +make this flat doubly +covered quadrilateral. + +So I'm taking this +as a piece of paper, + +but I can set the +creases however I want. + +I can fold it into this +five-sided, reflectionally + +symmetric polyhedron. + +All of these things are +convex, and they all + +have perfect coverage, +unlike an origami where + +I'm allowed to have +multiple layers. + +Here, one layer everywhere. + +Like sheet metal bending. + +So here, this pocket fits +perfectly into that tab. + +I make a tetrahedron. + +And the last thing you can +make with something called + +edge-to-edge [INAUDIBLE]-- +I'll talk about this more. + +There's an algorithm here +which, given a polygon, + +will list all of the +things it can fold into, + +in a reasonable amount of time. + +This is an octahedron. + +Those are the five +things you can + +make by edge-to-edge +[INAUDIBLE] of the cross. + +Let me stop that. + +So that's also on the web. + +You can watch it. + +In fact, all the lecture notes +I use, my handwritten notes, + +are on the class web page. + +The slides that I'm showing +are on the class web page. + +And when there's videos, +there's links to the videos, + +so it's all there for your +perusal if you miss something. + +The last thing I wanted to talk +about, because I've already + +done one, two and three, +there should always + +be one more thing. + +Fourth thing. + +And this is kind of funny, +because I don't really + +know where to put it. + +I'm still figuring it out. + +We have these +debates, because it's + +so easy when you're +thinking about linkages. + +Oh, that's one dimensional. + +Paper, that's two-dimensional. + +Polyhedra, well locally +it's two-dimensional, + +but it's three-dimensional. + +It's different. + +Different questions. + +Hinged dissections span +so many dimensions, + +I don't know where to put it. + +So four, hinged dissections. + +This didn't used to be +a topic in this class, + +and it's not a topic +in our textbook, + +because the result was proved +like last year or the year + +before out of this class. + +Three years ago. + +And the theorem is you take +any finite set of polygons, + +of the same area, +they can be folded + +from one chain of polygons +without collision. + +I'm going to say this +first, and but let me + +show you a simple example. + +Very simple. + +This is going to +be a little boring. + +Let me show you more +interesting example. + +Let's take an +equilateral triangle. + +I'm going to cut it +into two triangles, + +and then I'm going to +hinge them together here. + +So this is now a hinged +chain of polygons. + +If I open it up a little +bit, it looks like this. + +It looks a lot like +those vertex unfoldings + +I was showing before. + +And you can fold this +thing into one other shape. + +It's going to look like this. + +Not a very good drawing, +but you get the idea. + +Something like that. + +So this is what we call +a hinged dissection + +from this equilateral triangle +into this other triangle. + +And it's been an open +question for about 100 years. + +Can you always do this for +polygons of the same area? + +Turns out yes, not +only for two polygons-- + +you can take seven +polygons of equal area + +and there's one of +these chains of blocks + +that can fold into all of them. + +And I think I have +a little teaser + +picture of how the +construction goes. + +It's really crazy. + +You have this chain of blocks. + +It's changed in a particular +way and you say, well + +I really want that green piece-- +so think of it like this. + +You just have three triangles or +three pieces that you can fold. + +You say, well I really like +that green piece to be up top. + +Turns out you can make +all these crazy cuts. + +And if you fold it this +way, you get the green piece + +on the bottom. + +If you fold it this way, you +get the green piece on the top. + +It's one hinged dissection that +can move the pieces around, + +and basically pretend as if +the hinges weren't there, + +and make anything you want. + +So it's a bit complicated, +but it's really + +cool theory, something that +we worked on for like 10 years + +before finally solving. + +And it's practical. + +I mean this particular +construction isn't practical, + +but this is another way +to build transformers. + +Also to build sculpture. + +This is a sculpture by Laurie +Palmer that we collaborated on. + +It's an interactive sculpture. + +You pick up gloves, and +this is one chain of blocks. + +And the theorem is, this +particular chain of blocks-- + +about 1,000 blocks here-- +can make any shape made out + +of about 250 cubes. + +It's slightly skewed, but so +there's one hinged dissection + +that can fold into exponentially +many different shapes-- again, + +anything made out +of little cubes. + +And this is the +sculpture version. + +We also have various +prototypes of a robot that's + +a long chain of little cubes +or cube-like shapes, that + +can fold itself into +any 3D shape you want. + +It's, again, a different +kind of transformer, + +more inspired by +proteins, the way nature + +does it by long chains, +compared to the sheet-folding, + +origami-inspired approach. + +But it's all pretty +exciting and fun. + +Any questions? + +Jean? + +AUDIENCE: This is a 3D version +you were talking about. + +PROFESSOR: Yeah, I +pulled a fast one. + +That picture's 3D. + +This is about 2D. + +For 3D, you need the same area. + +You need one other +condition just + +for them to have a dissection. + +It's impossible to go from a +regular tetrahedron to a cube. + +This was one of Hilbert's +problems from 1900. + +And volumetrically +it's impossible to go + +from regular +tetrahedron to a cube, + +because the angles are wrong. + +It's an algebraic thing. + +And if you make things out +of little cubes, it's fine. + +You get that. + +There's no problem. + +But in general, there's +some tricky issues. + +It's easier to state for +2D, which is why I did, + +but it works in 3D, too, with +a little extra condition. + +And we'll talk about +that in the future. + +Other questions? + +All right, that's the +end of lecture one. \ No newline at end of file diff --git a/N4GOV3kzbdo.txt b/N4GOV3kzbdo.txt new file mode 100644 index 0000000000000000000000000000000000000000..6112d775867afae890ef14f4f2a02fffaad44656 --- /dev/null +++ b/N4GOV3kzbdo.txt @@ -0,0 +1,1763 @@ +align:start position:0% + +okay I'm there yes Bob + + align:start position:0% +okay I'm there yes Bob + + + align:start position:0% +okay I'm there yes Bob +and I'm Kaylen and our project was kind + + align:start position:0% +and I'm Kaylen and our project was kind + + + align:start position:0% +and I'm Kaylen and our project was kind +of a mini RPG I guess escaped from the + + align:start position:0% +of a mini RPG I guess escaped from the + + + align:start position:0% +of a mini RPG I guess escaped from the +zoo + + align:start position:0% +zoo + + + align:start position:0% +zoo +right here's like an opening cutscene so + + align:start position:0% +right here's like an opening cutscene so + + + align:start position:0% +right here's like an opening cutscene so +there's these cute little animals and + + align:start position:0% +there's these cute little animals and + + + align:start position:0% +there's these cute little animals and +they're gonna try and escape the zoo + + align:start position:0% +they're gonna try and escape the zoo + + + align:start position:0% +they're gonna try and escape the zoo +yeah the premise of our idea was that we + + align:start position:0% +yeah the premise of our idea was that we + + + align:start position:0% +yeah the premise of our idea was that we +wanted to have different animals that + + align:start position:0% +wanted to have different animals that + + + align:start position:0% +wanted to have different animals that +you could control that each had + + align:start position:0% +you could control that each had + + + align:start position:0% +you could control that each had +different ways of moving with the Kinect + + align:start position:0% +different ways of moving with the Kinect + + + align:start position:0% +different ways of moving with the Kinect +and we wanted the ways of moving to kind + + align:start position:0% +and we wanted the ways of moving to kind + + + align:start position:0% +and we wanted the ways of moving to kind +of I guess connect with the ways that + + align:start position:0% +of I guess connect with the ways that + + + align:start position:0% +of I guess connect with the ways that +the animals themselves move so we have + + align:start position:0% +the animals themselves move so we have + + + align:start position:0% +the animals themselves move so we have +you know the Gecko and the Frog who move + + align:start position:0% +you know the Gecko and the Frog who move + + + align:start position:0% +you know the Gecko and the Frog who move +very differently the penguin and the + + align:start position:0% +very differently the penguin and the + + + align:start position:0% +very differently the penguin and the +Rhino so we have four different types of + + align:start position:0% +Rhino so we have four different types of + + + align:start position:0% +Rhino so we have four different types of +controls that correspond with each + + align:start position:0% +controls that correspond with each + + + align:start position:0% +controls that correspond with each +animal these are just colored cubes and + + align:start position:0% +animal these are just colored cubes and + + + align:start position:0% +animal these are just colored cubes and +they unlock the respective colored doors + + align:start position:0% +they unlock the respective colored doors + + + align:start position:0% +they unlock the respective colored doors +and so you have you psych each animals a + + align:start position:0% +and so you have you psych each animals a + + + align:start position:0% +and so you have you psych each animals a +gimmick their special power to get each + + align:start position:0% +gimmick their special power to get each + + + align:start position:0% +gimmick their special power to get each +of the four keys you can escape the zoo + + align:start position:0% +of the four keys you can escape the zoo + + + align:start position:0% +of the four keys you can escape the zoo +so there's like a problem + + align:start position:0% + + + + align:start position:0% + +and this is like the backstory yeah so + + align:start position:0% +and this is like the backstory yeah so + + + align:start position:0% +and this is like the backstory yeah so +there's so many Grand Theft Auto yeah so + + align:start position:0% +there's so many Grand Theft Auto yeah so + + + align:start position:0% +there's so many Grand Theft Auto yeah so +cuz things were really interesting to + + align:start position:0% +cuz things were really interesting to + + + align:start position:0% +cuz things were really interesting to +Nathan yeah they quickly ran up we have + + align:start position:0% +Nathan yeah they quickly ran up we have + + + align:start position:0% +Nathan yeah they quickly ran up we have +like all these damaged files + + align:start position:0% +like all these damaged files + + + align:start position:0% +like all these damaged files +and so it ended up being a raw image + + align:start position:0% +and so it ended up being a raw image + + + align:start position:0% +and so it ended up being a raw image +with like 25 images attached to it and + + align:start position:0% +with like 25 images attached to it and + + + align:start position:0% +with like 25 images attached to it and +then a script that looks like every set + + align:start position:0% +then a script that looks like every set + + + align:start position:0% +then a script that looks like every set +amount of time switch to the next image + + align:start position:0% +amount of time switch to the next image + + + align:start position:0% +amount of time switch to the next image +and it's like a giant long piece of code + + align:start position:0% +and it's like a giant long piece of code + + + align:start position:0% +and it's like a giant long piece of code +because it's like if time is greater + + align:start position:0% +because it's like if time is greater + + + align:start position:0% +because it's like if time is greater +than 15 June image 5 okay we're in the + + align:start position:0% +than 15 June image 5 okay we're in the + + + align:start position:0% +than 15 June image 5 okay we're in the +game I'm already moving around penguin + + align:start position:0% +game I'm already moving around penguin + + + align:start position:0% +game I'm already moving around penguin +so Universal actually could be a little + + align:start position:0% +so Universal actually could be a little + + + align:start position:0% +so Universal actually could be a little +slump + + align:start position:0% +slump + + + align:start position:0% +slump +[Music] + + align:start position:0% + + + + align:start position:0% + +originally therefore the penguin was too + + align:start position:0% +originally therefore the penguin was too + + + align:start position:0% +originally therefore the penguin was too +kinda like this which is great kind of + + align:start position:0% +kinda like this which is great kind of + + + align:start position:0% +kinda like this which is great kind of +water + + align:start position:0% + + + + align:start position:0% + +however he kinda got hurt because the + + align:start position:0% +however he kinda got hurt because the + + + align:start position:0% +however he kinda got hurt because the +shoulders were really close to each + + align:start position:0% +shoulders were really close to each + + + align:start position:0% +shoulders were really close to each +other so in the code it would be like if + + align:start position:0% +other so in the code it would be like if + + + align:start position:0% +other so in the code it would be like if +one shoulders in front of the other and + + align:start position:0% +one shoulders in front of the other and + + + align:start position:0% +one shoulders in front of the other and +because they're closed we switch you to + + align:start position:0% +because they're closed we switch you to + + + align:start position:0% +because they're closed we switch you to +the hands so you can see I'm pretty + + align:start position:0% +the hands so you can see I'm pretty + + + align:start position:0% +the hands so you can see I'm pretty +loose with my hands just because it + + align:start position:0% +loose with my hands just because it + + + align:start position:0% +loose with my hands just because it +helps of the code so you saw the through + + align:start position:0% +helps of the code so you saw the through + + + align:start position:0% +helps of the code so you saw the through +support animals so part of this is going + + align:start position:0% +support animals so part of this is going + + + align:start position:0% +support animals so part of this is going +to be able to switch to animals + + align:start position:0% +to be able to switch to animals + + + align:start position:0% +to be able to switch to animals +if I could please switch you go frog + + align:start position:0% +if I could please switch you go frog + + + align:start position:0% +if I could please switch you go frog +email right same general controls of the + + align:start position:0% +email right same general controls of the + + + align:start position:0% +email right same general controls of the +left and right the Frog special ability + + align:start position:0% +left and right the Frog special ability + + + align:start position:0% +left and right the Frog special ability +is jumping which we wanted to be jumped + + align:start position:0% +is jumping which we wanted to be jumped + + + align:start position:0% +is jumping which we wanted to be jumped +but like the coach that was a little bit + + align:start position:0% +but like the coach that was a little bit + + + align:start position:0% +but like the coach that was a little bit +harder then I was able to do because we + + align:start position:0% +harder then I was able to do because we + + + align:start position:0% +harder then I was able to do because we +have a thing like the average of like + + align:start position:0% +have a thing like the average of like + + + align:start position:0% +have a thing like the average of like +your head position and then whenever you + + align:start position:0% +your head position and then whenever you + + + align:start position:0% +your head position and then whenever you +have an outlier jump so much so the Frog + + align:start position:0% +have an outlier jump so much so the Frog + + + align:start position:0% +have an outlier jump so much so the Frog +is kind of like a crawling motion from + + align:start position:0% +is kind of like a crawling motion from + + + align:start position:0% +is kind of like a crawling motion from +the other so um yeah we um + + align:start position:0% +the other so um yeah we um + + + align:start position:0% +the other so um yeah we um +so I built this entire world and we also + + align:start position:0% +so I built this entire world and we also + + + align:start position:0% +so I built this entire world and we also +use sort of terraforming one thing I + + align:start position:0% +use sort of terraforming one thing I + + + align:start position:0% +use sort of terraforming one thing I +really wanted I wanted the zoo to be + + align:start position:0% +really wanted I wanted the zoo to be + + + align:start position:0% +really wanted I wanted the zoo to be +like really crappy like like you need to + + align:start position:0% +like really crappy like like you need to + + + align:start position:0% +like really crappy like like you need to +feel like the animals like you want to + + align:start position:0% +feel like the animals like you want to + + + align:start position:0% +feel like the animals like you want to +get out of here so I found the worst + + align:start position:0% +get out of here so I found the worst + + + align:start position:0% +get out of here so I found the worst +clipart I could possibly find and if you + + align:start position:0% +clipart I could possibly find and if you + + + align:start position:0% +clipart I could possibly find and if you +notice the welcome to the zoo sign is in + + align:start position:0% +notice the welcome to the zoo sign is in + + + align:start position:0% +notice the welcome to the zoo sign is in +Comic Sans all of these models as well + + align:start position:0% +Comic Sans all of these models as well + + + align:start position:0% +Comic Sans all of these models as well +are we found them for like between five + + align:start position:0% +are we found them for like between five + + + align:start position:0% +are we found them for like between five +to ten dollars each on the unity asset + + align:start position:0% +to ten dollars each on the unity asset + + + align:start position:0% +to ten dollars each on the unity asset +store and they came fully animated + + align:start position:0% +store and they came fully animated + + + align:start position:0% +store and they came fully animated +there's actually a lot of animations we + + align:start position:0% +there's actually a lot of animations we + + + align:start position:0% +there's actually a lot of animations we +didn't use like the Frog and the penguin + + align:start position:0% +didn't use like the Frog and the penguin + + + align:start position:0% +didn't use like the Frog and the penguin +can like eat things yeah just make sure + + align:start position:0% +can like eat things yeah just make sure + + + align:start position:0% +can like eat things yeah just make sure +he doesn't jump out of the he can't + + align:start position:0% +he doesn't jump out of the he can't + + + align:start position:0% +he doesn't jump out of the he can't +escape yet yeah + + align:start position:0% + + + + align:start position:0% + +players shouldn't do kiss on Beijing + + align:start position:0% +players shouldn't do kiss on Beijing + + + align:start position:0% +players shouldn't do kiss on Beijing +morals so this is currently don't do + + align:start position:0% +morals so this is currently don't do + + + align:start position:0% +morals so this is currently don't do +anything they're not collisions oh yeah + + align:start position:0% + + + + align:start position:0% + +happens with models and not flat + + align:start position:0% +happens with models and not flat + + + align:start position:0% +happens with models and not flat +surfaces you can see one thing we didn't + + align:start position:0% +surfaces you can see one thing we didn't + + + align:start position:0% +surfaces you can see one thing we didn't +fix is that the horse still runs like + + align:start position:0% +fix is that the horse still runs like + + + align:start position:0% +fix is that the horse still runs like +the horse has like a controller attached + + align:start position:0% +the horse has like a controller attached + + + align:start position:0% +the horse has like a controller attached +to him that makes him run but he runs in + + align:start position:0% +to him that makes him run but he runs in + + + align:start position:0% +to him that makes him run but he runs in +place whenever you move the horse moves + + align:start position:0% +place whenever you move the horse moves + + + align:start position:0% +place whenever you move the horse moves +I like to think it's because he secretly + + align:start position:0% +I like to think it's because he secretly + + + align:start position:0% +I like to think it's because he secretly +wants to leave with you but he's not + + align:start position:0% +wants to leave with you but he's not + + + align:start position:0% +wants to leave with you but he's not +brave enough to do it sorry yeah this is + + align:start position:0% +brave enough to do it sorry yeah this is + + + align:start position:0% +brave enough to do it sorry yeah this is +this is grass there's a lot of grass so + + align:start position:0% +this is grass there's a lot of grass so + + + align:start position:0% +this is grass there's a lot of grass so +it loads slowly it's a pretty big world + + align:start position:0% +it loads slowly it's a pretty big world + + + align:start position:0% +it loads slowly it's a pretty big world +actually do you want to switch the + + align:start position:0% +actually do you want to switch the + + + align:start position:0% +actually do you want to switch the +penguin is probably the slowest this + + align:start position:0% +penguin is probably the slowest this + + + align:start position:0% +penguin is probably the slowest this +motion right here it was pretty fun so + + align:start position:0% +motion right here it was pretty fun so + + + align:start position:0% +motion right here it was pretty fun so +we knew we wanted like a switching + + align:start position:0% +we knew we wanted like a switching + + + align:start position:0% +we knew we wanted like a switching +motion but like logically we didn't want + + align:start position:0% +motion but like logically we didn't want + + + align:start position:0% +motion but like logically we didn't want +the player to be able to just do this + + align:start position:0% +the player to be able to just do this + + + align:start position:0% +the player to be able to just do this +and then I continued going for an effort + + align:start position:0% +and then I continued going for an effort + + + align:start position:0% +and then I continued going for an effort +forever so there has to be a check where + + align:start position:0% +forever so there has to be a check where + + + align:start position:0% +forever so there has to be a check where +if like if you move using left handed + + align:start position:0% +if like if you move using left handed + + + align:start position:0% +if like if you move using left handed +for the right once switch like this + + align:start position:0% +for the right once switch like this + + + align:start position:0% +for the right once switch like this +check the left and then you can't get + + align:start position:0% +check the left and then you can't get + + + align:start position:0% +check the left and then you can't get +back into that piece of code but it was + + align:start position:0% +back into that piece of code but it was + + + align:start position:0% +back into that piece of code but it was +in a update function and that means that + + align:start position:0% +in a update function and that means that + + + align:start position:0% +in a update function and that means that +it + + align:start position:0% +it + + + align:start position:0% +it +every frame so it was running every + + align:start position:0% +every frame so it was running every + + + align:start position:0% +every frame so it was running every +frame but you could only go left or + + align:start position:0% +frame but you could only go left or + + + align:start position:0% +frame but you could only go left or +right one frame so then you're moving + + align:start position:0% +right one frame so then you're moving + + + align:start position:0% +right one frame so then you're moving +one thing at a time + + align:start position:0% +one thing at a time + + + align:start position:0% +one thing at a time +which is hilarious look so the solution + + align:start position:0% +which is hilarious look so the solution + + + align:start position:0% +which is hilarious look so the solution +to that was 250 invisible wall here yes + + align:start position:0% +to that was 250 invisible wall here yes + + + align:start position:0% +to that was 250 invisible wall here yes +I'm gonna show that so paying special + + align:start position:0% +I'm gonna show that so paying special + + + align:start position:0% +I'm gonna show that so paying special +abilities gonna be able to slide down + + align:start position:0% +abilities gonna be able to slide down + + + align:start position:0% +abilities gonna be able to slide down +things so to keep other animals from + + align:start position:0% +things so to keep other animals from + + + align:start position:0% +things so to keep other animals from +using that ability it's a nice little + + align:start position:0% +using that ability it's a nice little + + + align:start position:0% +using that ability it's a nice little +invisible wall so I'm gonna switch back + + align:start position:0% +invisible wall so I'm gonna switch back + + + align:start position:0% +invisible wall so I'm gonna switch back +to penguin and there was like a counter + + align:start position:0% +to penguin and there was like a counter + + + align:start position:0% +to penguin and there was like a counter +they counted how many frames you are + + align:start position:0% +they counted how many frames you are + + + align:start position:0% +they counted how many frames you are +allowed to stick one hand in front of + + align:start position:0% +allowed to stick one hand in front of + + + align:start position:0% +allowed to stick one hand in front of +the other and 30 works pretty well it + + align:start position:0% +the other and 30 works pretty well it + + + align:start position:0% +the other and 30 works pretty well it +was like it's felt kind of natural with + + align:start position:0% +was like it's felt kind of natural with + + + align:start position:0% +was like it's felt kind of natural with +like like a pattern that you would use + + align:start position:0% +like like a pattern that you would use + + + align:start position:0% +like like a pattern that you would use +or a time that you would used to swim + + align:start position:0% +or a time that you would used to swim + + + align:start position:0% +or a time that you would used to swim +let's see other things switch between + + align:start position:0% +let's see other things switch between + + + align:start position:0% +let's see other things switch between +the animals was interesting I originally + + align:start position:0% +the animals was interesting I originally + + + align:start position:0% +the animals was interesting I originally +tried attach them all to a single player + + align:start position:0% +tried attach them all to a single player + + + align:start position:0% +tried attach them all to a single player +and then having them move the player + + align:start position:0% +and then having them move the player + + + align:start position:0% +and then having them move the player +object so that way it moved all four of + + align:start position:0% +object so that way it moved all four of + + + align:start position:0% +object so that way it moved all four of +the models whether or not they were + + align:start position:0% +the models whether or not they were + + + align:start position:0% +the models whether or not they were +invisible at the same time but that kind + + align:start position:0% +invisible at the same time but that kind + + + align:start position:0% +invisible at the same time but that kind +of caused a perpetual motion thing where + + align:start position:0% +of caused a perpetual motion thing where + + + align:start position:0% +of caused a perpetual motion thing where +like one animal would move the player + + align:start position:0% +like one animal would move the player + + + align:start position:0% +like one animal would move the player +object but then because it was attached + + align:start position:0% +object but then because it was attached + + + align:start position:0% +object but then because it was attached +the player object the player object + + align:start position:0% +the player object the player object + + + align:start position:0% +the player object the player object +remove the animal it's like you would + + align:start position:0% +remove the animal it's like you would + + + align:start position:0% +remove the animal it's like you would +hit the game in like Sun + + align:start position:0% +hit the game in like Sun + + + align:start position:0% +hit the game in like Sun +the penguin starts like waltzing off the + + align:start position:0% +the penguin starts like waltzing off the + + + align:start position:0% +the penguin starts like waltzing off the +playing field I think I'm on flat ground + + align:start position:0% +playing field I think I'm on flat ground + + + align:start position:0% +playing field I think I'm on flat ground +message to Rhino please the Rhino school + + align:start position:0% +message to Rhino please the Rhino school + + + align:start position:0% +message to Rhino please the Rhino school +didn't come with a client so it's just + + align:start position:0% +didn't come with a client so it's just + + + align:start position:0% +didn't come with a client so it's just +have a box but right this way a move is + + align:start position:0% +have a box but right this way a move is + + + align:start position:0% +have a box but right this way a move is +to charge forward get those abilities to + + align:start position:0% +to charge forward get those abilities to + + + align:start position:0% +to charge forward get those abilities to +climb up walls + + align:start position:0% +climb up walls + + + align:start position:0% +climb up walls +however due to time constraints and sets + + align:start position:0% +however due to time constraints and sets + + + align:start position:0% +however due to time constraints and sets +planet walls we're gonna need some + + align:start position:0% +planet walls we're gonna need some + + + align:start position:0% +planet walls we're gonna need some +matches + + align:start position:0% + + + + align:start position:0% + +enough you can get his key so would you + + align:start position:0% +enough you can get his key so would you + + + align:start position:0% +enough you can get his key so would you +like to talk about in disease yes so + + align:start position:0% +like to talk about in disease yes so + + + align:start position:0% +like to talk about in disease yes so +we're gonna go visit some of the NPCs + + align:start position:0% +we're gonna go visit some of the NPCs + + + align:start position:0% +we're gonna go visit some of the NPCs +now there are interacts that you engage + + align:start position:0% +now there are interacts that you engage + + + align:start position:0% +now there are interacts that you engage +with by hitting a little invisible + + align:start position:0% +with by hitting a little invisible + + + align:start position:0% +with by hitting a little invisible +Collider box there's a gorilla and a + + align:start position:0% +Collider box there's a gorilla and a + + + align:start position:0% +Collider box there's a gorilla and a +horse neither of whom want to escape + + align:start position:0% +horse neither of whom want to escape + + + align:start position:0% +horse neither of whom want to escape +with you the gorillas in that + + align:start position:0% +with you the gorillas in that + + + align:start position:0% +with you the gorillas in that +sad-looking cage and the horses you know + + align:start position:0% +sad-looking cage and the horses you know + + + align:start position:0% +sad-looking cage and the horses you know +standing behind him and each interact is + + align:start position:0% +standing behind him and each interact is + + + align:start position:0% +standing behind him and each interact is +specific to the animals so we're going + + align:start position:0% +specific to the animals so we're going + + + align:start position:0% +specific to the animals so we're going +to interact with gorilla as right now + + align:start position:0% +to interact with gorilla as right now + + + align:start position:0% +to interact with gorilla as right now +see good exercise + + align:start position:0% +see good exercise + + + align:start position:0% +see good exercise +oh no you keep the horse it could + + align:start position:0% +oh no you keep the horse it could + + + align:start position:0% +oh no you keep the horse it could +actually be the image + + align:start position:0% +actually be the image + + + align:start position:0% +actually be the image +we've we had to make a Harambee + + align:start position:0% +we've we had to make a Harambee + + + align:start position:0% +we've we had to make a Harambee +reference I mean it's a gorilla in a zoo + + align:start position:0% +reference I mean it's a gorilla in a zoo + + + align:start position:0% +reference I mean it's a gorilla in a zoo +what are we gonna do + + align:start position:0% + + + + align:start position:0% + +talk about cut scenes cut scenes were + + align:start position:0% +talk about cut scenes cut scenes were + + + align:start position:0% +talk about cut scenes cut scenes were +fun oh it show it automatically goes to + + align:start position:0% +fun oh it show it automatically goes to + + + align:start position:0% +fun oh it show it automatically goes to +the horse well it's okay the horse but + + align:start position:0% +the horse well it's okay the horse but + + + align:start position:0% +the horse well it's okay the horse but +it only did part of the horse cutscene + + align:start position:0% +it only did part of the horse cutscene + + + align:start position:0% +it only did part of the horse cutscene +maybe the images were just put there + + align:start position:0% +maybe the images were just put there + + + align:start position:0% +maybe the images were just put there +back soon + + align:start position:0% +back soon + + + align:start position:0% +back soon +whatever anyways so this is the worst + + align:start position:0% + + + + align:start position:0% + +yeah so as we'll find out in a minute + + align:start position:0% +yeah so as we'll find out in a minute + + + align:start position:0% +yeah so as we'll find out in a minute +we're gonna leave oh oh well oh we must + + align:start position:0% +we're gonna leave oh oh well oh we must + + + align:start position:0% +we're gonna leave oh oh well oh we must +have still well so we're gonna go + + align:start position:0% +have still well so we're gonna go + + + align:start position:0% +have still well so we're gonna go +interact with all the voices here we'll + + align:start position:0% +interact with all the voices here we'll + + + align:start position:0% +interact with all the voices here we'll +switch with penguin oh that's why yeah + + align:start position:0% +switch with penguin oh that's why yeah + + + align:start position:0% +switch with penguin oh that's why yeah +so now we'll go interact okay we'll have + + align:start position:0% +so now we'll go interact okay we'll have + + + align:start position:0% +so now we'll go interact okay we'll have +frog here we go when I was like testing + + align:start position:0% +frog here we go when I was like testing + + + align:start position:0% +frog here we go when I was like testing +to get around I had to choose like + + align:start position:0% +to get around I had to choose like + + + align:start position:0% +to get around I had to choose like +different animals to get around so hi + + align:start position:0% +different animals to get around so hi + + + align:start position:0% +different animals to get around so hi +frog was convenient because of the + + align:start position:0% +frog was convenient because of the + + + align:start position:0% +frog was convenient because of the +jumping was pretty fast + + align:start position:0% +jumping was pretty fast + + + align:start position:0% +jumping was pretty fast +the rhinos the fastest but because the + + align:start position:0% +the rhinos the fastest but because the + + + align:start position:0% +the rhinos the fastest but because the +Rhino hitbox is literally a box some + + align:start position:0% +Rhino hitbox is literally a box some + + + align:start position:0% +Rhino hitbox is literally a box some +weird things happen where like it would + + align:start position:0% +weird things happen where like it would + + + align:start position:0% +weird things happen where like it would +hit a log and then start flying off into + + align:start position:0% +hit a log and then start flying off into + + + align:start position:0% +hit a log and then start flying off into +space or like flip over and tumble and + + align:start position:0% +space or like flip over and tumble and + + + align:start position:0% +space or like flip over and tumble and +crazy things so it was really like the + + align:start position:0% +crazy things so it was really like the + + + align:start position:0% +crazy things so it was really like the +safe route to get to places but if I was + + align:start position:0% +safe route to get to places but if I was + + + align:start position:0% +safe route to get to places but if I was +going and reading ambitious oh we're + + align:start position:0% +going and reading ambitious oh we're + + + align:start position:0% +going and reading ambitious oh we're +tilted + + align:start position:0% + + + + align:start position:0% + +I would like go to RINO and I have fun + + align:start position:0% +I would like go to RINO and I have fun + + + align:start position:0% +I would like go to RINO and I have fun +pretending to be like an airplane it's + + align:start position:0% +pretending to be like an airplane it's + + + align:start position:0% +pretending to be like an airplane it's +called a Dutch ankle - it's purposeful + + align:start position:0% + + + + align:start position:0% + +this is Lasky's we're almost there huh + + align:start position:0% +this is Lasky's we're almost there huh + + + align:start position:0% +this is Lasky's we're almost there huh +should I switch yeah + + align:start position:0% + + + + align:start position:0% + +is frog faster than gecko because the + + align:start position:0% +is frog faster than gecko because the + + + align:start position:0% +is frog faster than gecko because the +judge right now + + align:start position:0% + + + + align:start position:0% + +so the Rhino special ability is a + + align:start position:0% +so the Rhino special ability is a + + + align:start position:0% +so the Rhino special ability is a +meeting with break down boxes the key + + align:start position:0% + + + + align:start position:0% + +however the very tight corridors of the + + align:start position:0% +however the very tight corridors of the + + + align:start position:0% +however the very tight corridors of the +club can't really turn to get out yeah + + align:start position:0% +club can't really turn to get out yeah + + + align:start position:0% +club can't really turn to get out yeah +this sort of another part of the premise + + align:start position:0% +this sort of another part of the premise + + + align:start position:0% +this sort of another part of the premise +was that we wanted to make we wanted to + + align:start position:0% +was that we wanted to make we wanted to + + + align:start position:0% +was that we wanted to make we wanted to +make the characters be animals that like + + align:start position:0% +make the characters be animals that like + + + align:start position:0% +make the characters be animals that like +nobody would miss if they left the zoo + + align:start position:0% +nobody would miss if they left the zoo + + + align:start position:0% +nobody would miss if they left the zoo +except for rhino who everybody would + + align:start position:0% +except for rhino who everybody would + + + align:start position:0% +except for rhino who everybody would +miss so rhino needs a lot of help that's + + align:start position:0% +miss so rhino needs a lot of help that's + + + align:start position:0% +miss so rhino needs a lot of help that's +the plot reason so if you know the + + align:start position:0% +the plot reason so if you know the + + + align:start position:0% +the plot reason so if you know the +beginning there were doors near the + + align:start position:0% +beginning there were doors near the + + + align:start position:0% +beginning there were doors near the +entrance here they're all gone + + align:start position:0% +entrance here they're all gone + + + align:start position:0% +entrance here they're all gone +you know the colored keys got rid of the + + align:start position:0% +you know the colored keys got rid of the + + + align:start position:0% +you know the colored keys got rid of the +respective color doors this all silicon + + align:start position:0% +respective color doors this all silicon + + + align:start position:0% +respective color doors this all silicon +short ending cutscene I'm going to make + + align:start position:0% +short ending cutscene I'm going to make + + + align:start position:0% +short ending cutscene I'm going to make +it + + align:start position:0% + + + + align:start position:0% + +yeah + + align:start position:0% + + + + align:start position:0% + +[Music] \ No newline at end of file diff --git a/N4vMgwWT-80.txt b/N4vMgwWT-80.txt new file mode 100644 index 0000000000000000000000000000000000000000..12fff01f369fee35998ae73820df0899440678b1 --- /dev/null +++ b/N4vMgwWT-80.txt @@ -0,0 +1,6251 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT OpenCourseWare continue to + + align:start position:0% +will help MIT OpenCourseWare continue to + + + align:start position:0% +will help MIT OpenCourseWare continue to +offer high quality educational resources + + align:start position:0% +offer high quality educational resources + + + align:start position:0% +offer high quality educational resources +for free + + align:start position:0% +for free + + + align:start position:0% +for free +to make a donation or to view additional + + align:start position:0% +to make a donation or to view additional + + + align:start position:0% +to make a donation or to view additional +materials from hundreds of MIT courses + + align:start position:0% +materials from hundreds of MIT courses + + + align:start position:0% +materials from hundreds of MIT courses +visit MIT opencourseware at ocw.mit.edu + + align:start position:0% + + + + align:start position:0% + +so today we're gonna go from the + + align:start position:0% +so today we're gonna go from the + + + align:start position:0% +so today we're gonna go from the +classical mechanical treatment of the + + align:start position:0% +classical mechanical treatment of the + + + align:start position:0% +classical mechanical treatment of the +harmonic oscillator to a quantum + + align:start position:0% +harmonic oscillator to a quantum + + + align:start position:0% +harmonic oscillator to a quantum +mechanical treatment and I warned you + + align:start position:0% +mechanical treatment and I warned you + + + align:start position:0% +mechanical treatment and I warned you +that I intentionally am going to make + + align:start position:0% +that I intentionally am going to make + + + align:start position:0% +that I intentionally am going to make +this look bad because the the the + + align:start position:0% +this look bad because the the the + + + align:start position:0% +this look bad because the the the +semi-classical approach at the begin at + + align:start position:0% +semi-classical approach at the begin at + + + align:start position:0% +semi-classical approach at the begin at +the end of this lecture will make it all + + align:start position:0% +the end of this lecture will make it all + + + align:start position:0% +the end of this lecture will make it all +really simple and then on Monday I'll + + align:start position:0% +really simple and then on Monday I'll + + + align:start position:0% +really simple and then on Monday I'll +introduce creation and annihilation + + align:start position:0% +introduce creation and annihilation + + + align:start position:0% +introduce creation and annihilation +operators which makes the harmonic + + align:start position:0% +operators which makes the harmonic + + + align:start position:0% +operators which makes the harmonic +oscillator simpler than the particle in + + align:start position:0% +oscillator simpler than the particle in + + + align:start position:0% +oscillator simpler than the particle in +a box you can't believe that but alright + + align:start position:0% +a box you can't believe that but alright + + + align:start position:0% +a box you can't believe that but alright +so last time it we treated the the + + align:start position:0% +so last time it we treated the the + + + align:start position:0% +so last time it we treated the the +harmonic oscillator classically and so + + align:start position:0% +harmonic oscillator classically and so + + + align:start position:0% +harmonic oscillator classically and so +we derived the equation of motion from + + align:start position:0% +we derived the equation of motion from + + + align:start position:0% +we derived the equation of motion from +force is equal to mass times + + align:start position:0% +force is equal to mass times + + + align:start position:0% +force is equal to mass times +acceleration and we solved it and we saw + + align:start position:0% +acceleration and we solved it and we saw + + + align:start position:0% +acceleration and we solved it and we saw +that we have this quantity Omega which + + align:start position:0% +that we have this quantity Omega which + + + align:start position:0% +that we have this quantity Omega which +initially I just introduced as a + + align:start position:0% +initially I just introduced as a + + + align:start position:0% +initially I just introduced as a +constant which was a way of combining + + align:start position:0% +constant which was a way of combining + + + align:start position:0% +constant which was a way of combining +the force constant and the mass and then + + align:start position:0% +the force constant and the mass and then + + + align:start position:0% +the force constant and the mass and then +I showed that the period of oscillation + + align:start position:0% +I showed that the period of oscillation + + + align:start position:0% +I showed that the period of oscillation +is 1 over the frequency which is 2 PI + + align:start position:0% +is 1 over the frequency which is 2 PI + + + align:start position:0% +is 1 over the frequency which is 2 PI +over Omega now one of the things that + + align:start position:0% +over Omega now one of the things that + + + align:start position:0% +over Omega now one of the things that +people have trouble remembering under + + align:start position:0% +people have trouble remembering under + + + align:start position:0% +people have trouble remembering under +exam pressure is turning points and this + + align:start position:0% +exam pressure is turning points and this + + + align:start position:0% +exam pressure is turning points and this +comes when the energy is equal to the + + align:start position:0% +comes when the energy is equal to the + + + align:start position:0% +comes when the energy is equal to the +potential at a turning point + + align:start position:0% +potential at a turning point + + + align:start position:0% +potential at a turning point +oops and since the potential is 1/2 KX + + align:start position:0% +oops and since the potential is 1/2 KX + + + align:start position:0% +oops and since the potential is 1/2 KX +squared we get original the equation for + + align:start position:0% +squared we get original the equation for + + + align:start position:0% +squared we get original the equation for +the turning point at a given energy + + align:start position:0% +the turning point at a given energy + + + align:start position:0% +the turning point at a given energy +which is equal to plus or minus the + + align:start position:0% +which is equal to plus or minus the + + + align:start position:0% +which is equal to plus or minus the +square root of 2 e over K + + align:start position:0% + + + + align:start position:0% + +now when you're drawing pictures there + + align:start position:0% +now when you're drawing pictures there + + + align:start position:0% +now when you're drawing pictures there +are certain things that anchor the + + align:start position:0% +are certain things that anchor the + + + align:start position:0% +are certain things that anchor the +pictures like turning points okay + + align:start position:0% +pictures like turning points okay + + + align:start position:0% +pictures like turning points okay +and now at the end of the previous + + align:start position:0% +and now at the end of the previous + + + align:start position:0% +and now at the end of the previous +lecture I calculated the classical + + align:start position:0% +lecture I calculated the classical + + + align:start position:0% +lecture I calculated the classical +mechanical average and we use we use + + align:start position:0% +mechanical average and we use we use + + + align:start position:0% +mechanical average and we use we use +this kind of notation in classical + + align:start position:0% +this kind of notation in classical + + + align:start position:0% +this kind of notation in classical +mechanics sometimes we use this notation + + align:start position:0% +mechanics sometimes we use this notation + + + align:start position:0% +mechanics sometimes we use this notation +too but this is what we mean by the + + align:start position:0% +too but this is what we mean by the + + + align:start position:0% +too but this is what we mean by the +average value in quantum mechanics and + + align:start position:0% +average value in quantum mechanics and + + + align:start position:0% +average value in quantum mechanics and +we found that this was the total energy + + align:start position:0% +we found that this was the total energy + + + align:start position:0% +we found that this was the total energy +divided by two and the average momentum + + align:start position:0% + + + + align:start position:0% + +is the energy divided by two and that's + + align:start position:0% +is the energy divided by two and that's + + + align:start position:0% +is the energy divided by two and that's +a basis for some insight because as a + + align:start position:0% +a basis for some insight because as a + + + align:start position:0% +a basis for some insight because as a +harmonic oscillator moves it throws + + align:start position:0% +harmonic oscillator moves it throws + + + align:start position:0% +harmonic oscillator moves it throws +energy back and forth between kinetic + + align:start position:0% +energy back and forth between kinetic + + + align:start position:0% +energy back and forth between kinetic +energy and potential energy and then one + + align:start position:0% +energy and potential energy and then one + + + align:start position:0% +energy and potential energy and then one +of my favorite things and one of my + + align:start position:0% +of my favorite things and one of my + + + align:start position:0% +of my favorite things and one of my +favorite tortures on short answers is + + align:start position:0% + + + + align:start position:0% + +the average values and does anybody want + + align:start position:0% +the average values and does anybody want + + + align:start position:0% +the average values and does anybody want +to remind the class the easy way or the + + align:start position:0% +to remind the class the easy way or the + + + align:start position:0% +to remind the class the easy way or the +two easy ways to know what this is and + + align:start position:0% +two easy ways to know what this is and + + + align:start position:0% +two easy ways to know what this is and +the person who answered the question + + align:start position:0% +the person who answered the question + + + align:start position:0% +the person who answered the question +last time is disqualified + + align:start position:0% +last time is disqualified + + + align:start position:0% +last time is disqualified +yes symmetry but there's a symmetry the + + align:start position:0% +yes symmetry but there's a symmetry the + + + align:start position:0% +yes symmetry but there's a symmetry the +system's symmetrical yes there it'll be + + align:start position:0% +system's symmetrical yes there it'll be + + + align:start position:0% +system's symmetrical yes there it'll be +actually that symmetry point yes so and + + align:start position:0% +actually that symmetry point yes so and + + + align:start position:0% +actually that symmetry point yes so and +the other is the harmonic oscillator + + align:start position:0% +the other is the harmonic oscillator + + + align:start position:0% +the other is the harmonic oscillator +isn't moving and so there's no way that + + align:start position:0% +isn't moving and so there's no way that + + + align:start position:0% +isn't moving and so there's no way that +the coordinate that the average value of + + align:start position:0% +the coordinate that the average value of + + + align:start position:0% +the coordinate that the average value of +either the coordinate or the momentum + + align:start position:0% +either the coordinate or the momentum + + + align:start position:0% +either the coordinate or the momentum +could be different from zero however you + + align:start position:0% +could be different from zero however you + + + align:start position:0% +could be different from zero however you +do it you want to be doing it in seconds + + align:start position:0% +do it you want to be doing it in seconds + + + align:start position:0% +do it you want to be doing it in seconds +not minutes and certainly not my + + align:start position:0% +not minutes and certainly not my + + + align:start position:0% +not minutes and certainly not my +calculated integral and now x squared + + align:start position:0% +calculated integral and now x squared + + + align:start position:0% +calculated integral and now x squared +and P squared they're easy to especially + + align:start position:0% +and P squared they're easy to especially + + + align:start position:0% +and P squared they're easy to especially +if you know T and V + + align:start position:0% +if you know T and V + + + align:start position:0% + +and so we then use those to calculate + + align:start position:0% +and so we then use those to calculate + + + align:start position:0% +and so we then use those to calculate +the variance and that's defined as the + + align:start position:0% +the variance and that's defined as the + + + align:start position:0% +the variance and that's defined as the +average value of the square minus the + + align:start position:0% +average value of the square minus the + + + align:start position:0% +average value of the square minus the +square of the average square root and + + align:start position:0% +square of the average square root and + + + align:start position:0% +square of the average square root and +what we find is that the variance of x + + align:start position:0% +what we find is that the variance of x + + + align:start position:0% +what we find is that the variance of x +times the variance of P is equal to e + + align:start position:0% +times the variance of P is equal to e + + + align:start position:0% +times the variance of P is equal to e +over Omega so as you go up in energy + + align:start position:0% +over Omega so as you go up in energy + + + align:start position:0% +over Omega so as you go up in energy +this this joint uncertainty increases + + align:start position:0% +this this joint uncertainty increases + + + align:start position:0% +this this joint uncertainty increases +and we'll find that that also is true + + align:start position:0% +and we'll find that that also is true + + + align:start position:0% +and we'll find that that also is true +for water mechanics so this is this is + + align:start position:0% +for water mechanics so this is this is + + + align:start position:0% +for water mechanics so this is this is +sort of the the kind of questions you + + align:start position:0% +sort of the the kind of questions you + + + align:start position:0% +sort of the the kind of questions you +want to be asking in quantum mechanics + + align:start position:0% +want to be asking in quantum mechanics + + + align:start position:0% +want to be asking in quantum mechanics +and you want to be able to be guided by + + align:start position:0% +and you want to be able to be guided by + + + align:start position:0% +and you want to be able to be guided by +what you know from classical mechanics + + align:start position:0% +what you know from classical mechanics + + + align:start position:0% +what you know from classical mechanics +and you want to be able to do it fast + + align:start position:0% +and you want to be able to do it fast + + + align:start position:0% +and you want to be able to do it fast +okay so today's menu is what I would + + align:start position:0% +okay so today's menu is what I would + + + align:start position:0% +okay so today's menu is what I would +call this lecture is gratuitous + + align:start position:0% +call this lecture is gratuitous + + + align:start position:0% +call this lecture is gratuitous +gratuitous complexity does everybody + + align:start position:0% +gratuitous complexity does everybody + + + align:start position:0% +gratuitous complexity does everybody +know what gratuitous means okay it's + + align:start position:0% +know what gratuitous means okay it's + + + align:start position:0% +know what gratuitous means okay it's +also this is a this is one of my + + align:start position:0% +also this is a this is one of my + + + align:start position:0% +also this is a this is one of my +favorite Bob isms and you'll hear other + + align:start position:0% +favorite Bob isms and you'll hear other + + + align:start position:0% +favorite Bob isms and you'll hear other +Bob isms be during the course of this + + align:start position:0% +Bob isms be during the course of this + + + align:start position:0% +Bob isms be during the course of this +course what I want you to be able to do + + align:start position:0% +course what I want you to be able to do + + + align:start position:0% +course what I want you to be able to do +for a lot of quantum mechanical problems + + align:start position:0% +for a lot of quantum mechanical problems + + + align:start position:0% +for a lot of quantum mechanical problems +is to know the answer or know what + + align:start position:0% +is to know the answer or know what + + + align:start position:0% +is to know the answer or know what +things look like without doing a + + align:start position:0% +things look like without doing a + + + align:start position:0% +things look like without doing a +calculation in particular not solving a + + align:start position:0% +calculation in particular not solving a + + + align:start position:0% +calculation in particular not solving a +differential equation or evaluating any + + align:start position:0% +differential equation or evaluating any + + + align:start position:0% +differential equation or evaluating any +integrals you want to be able to draw + + align:start position:0% +integrals you want to be able to draw + + + align:start position:0% +integrals you want to be able to draw +these pictures instantly now in the + + align:start position:0% +these pictures instantly now in the + + + align:start position:0% +these pictures instantly now in the +modern age everyone has a pocket a cell + + align:start position:0% +modern age everyone has a pocket a cell + + + align:start position:0% +modern age everyone has a pocket a cell +phone and one could have a program in + + align:start position:0% +phone and one could have a program in + + + align:start position:0% +phone and one could have a program in +there to calculate what anything you + + align:start position:0% +there to calculate what anything you + + + align:start position:0% +there to calculate what anything you +wanted for a harmonic oscillator but + + align:start position:0% +wanted for a harmonic oscillator but + + + align:start position:0% +wanted for a harmonic oscillator but +chances are you won't be super + + align:start position:0% +chances are you won't be super + + + align:start position:0% +chances are you won't be super +you won't be prepared for that and if if + + align:start position:0% +you won't be prepared for that and if if + + + align:start position:0% +you won't be prepared for that and if if +you want to have insights into how do + + align:start position:0% +you want to have insights into how do + + + align:start position:0% +you want to have insights into how do +various things you want to know about + + align:start position:0% +various things you want to know about + + + align:start position:0% +various things you want to know about +harmonic harmonic oscillators come about + + align:start position:0% +harmonic harmonic oscillators come about + + + align:start position:0% +harmonic harmonic oscillators come about +you need the pictures as opposed to the + + align:start position:0% +you need the pictures as opposed to the + + + align:start position:0% +you need the pictures as opposed to the +computer program now the pictures + + align:start position:0% +computer program now the pictures + + + align:start position:0% +computer program now the pictures +involved involve an advance investment + + align:start position:0% +involved involve an advance investment + + + align:start position:0% +involved involve an advance investment +of energy you want to understand every + + align:start position:0% +of energy you want to understand every + + + align:start position:0% +of energy you want to understand every +detail of these little pictures ok so + + align:start position:0% +detail of these little pictures ok so + + + align:start position:0% +detail of these little pictures ok so +I'm going to write the Schrodinger + + align:start position:0% +I'm going to write the Schrodinger + + + align:start position:0% +I'm going to write the Schrodinger +equation I'm going to clean it up to get + + align:start position:0% +equation I'm going to clean it up to get + + + align:start position:0% +equation I'm going to clean it up to get +rid of units which makes it universal so + + align:start position:0% +rid of units which makes it universal so + + + align:start position:0% +rid of units which makes it universal so +it becomes a dimension I see + + align:start position:0% +it becomes a dimension I see + + + align:start position:0% +it becomes a dimension I see +dimensionless equation and the unit + + align:start position:0% +dimensionless equation and the unit + + + align:start position:0% +dimensionless equation and the unit +removal or the the the thing that takes + + align:start position:0% +removal or the the the thing that takes + + + align:start position:0% +removal or the the the thing that takes +takes you from a specific problem where + + align:start position:0% +takes you from a specific problem where + + + align:start position:0% +takes you from a specific problem where +there's a particular force constant and + + align:start position:0% +there's a particular force constant and + + + align:start position:0% +there's a particular force constant and +a particular reduced mass and makes it + + align:start position:0% +a particular reduced mass and makes it + + + align:start position:0% +a particular reduced mass and makes it +into a general problem there is one or + + align:start position:0% +into a general problem there is one or + + + align:start position:0% +into a general problem there is one or +two constants that combine those things + + align:start position:0% +two constants that combine those things + + + align:start position:0% +two constants that combine those things +and you've taken them out at the end of + + align:start position:0% +and you've taken them out at the end of + + + align:start position:0% +and you've taken them out at the end of +a calculation if you need to have real + + align:start position:0% +a calculation if you need to have real + + + align:start position:0% +a calculation if you need to have real +units you can put those back in and + + align:start position:0% +units you can put those back in and + + + align:start position:0% +units you can put those back in and +that's a very wonderful thing in that + + align:start position:0% +that's a very wonderful thing in that + + + align:start position:0% +that's a very wonderful thing in that +that enables us to to draw pictures + + align:start position:0% +that enables us to to draw pictures + + + align:start position:0% +that enables us to to draw pictures +without thinking about what is the + + align:start position:0% +without thinking about what is the + + + align:start position:0% +without thinking about what is the +problem ok and then the solution of this + + align:start position:0% +problem ok and then the solution of this + + + align:start position:0% +problem ok and then the solution of this +differential equation which is actually + + align:start position:0% +differential equation which is actually + + + align:start position:0% +differential equation which is actually +quite an awful differential equation at + + align:start position:0% +quite an awful differential equation at + + + align:start position:0% +quite an awful differential equation at +least for people who are not + + align:start position:0% +least for people who are not + + + align:start position:0% +least for people who are not +mathematicians and the solution can be + + align:start position:0% +mathematicians and the solution can be + + + align:start position:0% +mathematicians and the solution can be +expressed as the product of a Gaussian + + align:start position:0% +expressed as the product of a Gaussian + + + align:start position:0% +expressed as the product of a Gaussian +function which goes to 0 at plus and + + align:start position:0% +function which goes to 0 at plus and + + + align:start position:0% +function which goes to 0 at plus and +minus infinity so it makes the function + + align:start position:0% +minus infinity so it makes the function + + + align:start position:0% +minus infinity so it makes the function +well-behaved times something that + + align:start position:0% +well-behaved times something that + + + align:start position:0% +well-behaved times something that +produces nodes a polynomial does anyone + + align:start position:0% +produces nodes a polynomial does anyone + + + align:start position:0% +produces nodes a polynomial does anyone +who are give me a definition of a + + align:start position:0% +who are give me a definition of a + + + align:start position:0% +who are give me a definition of a +polynomial + + align:start position:0% + + + + align:start position:0% + +silence okay your turn the linear + + align:start position:0% +silence okay your turn the linear + + + align:start position:0% +silence okay your turn the linear +combination of some numbers taken two + + align:start position:0% +combination of some numbers taken two + + + align:start position:0% +combination of some numbers taken two +different power write a sum of integer + + align:start position:0% +different power write a sum of integer + + + align:start position:0% +different power write a sum of integer +powers of a variable okay and so when we + + align:start position:0% +powers of a variable okay and so when we + + + align:start position:0% +powers of a variable okay and so when we +take a derivative of a polynomial we + + align:start position:0% +take a derivative of a polynomial we + + + align:start position:0% +take a derivative of a polynomial we +reduce the order of the polynomial a + + align:start position:0% +reduce the order of the polynomial a + + + align:start position:0% +reduce the order of the polynomial a +little bit of thought if you have a + + align:start position:0% +little bit of thought if you have a + + + align:start position:0% +little bit of thought if you have a +first-order polynomial there'll be one + + align:start position:0% +first-order polynomial there'll be one + + + align:start position:0% +first-order polynomial there'll be one +note if there's a second-order there'll + + align:start position:0% +note if there's a second-order there'll + + + align:start position:0% +note if there's a second-order there'll +be two notes and nodes are very + + align:start position:0% +be two notes and nodes are very + + + align:start position:0% +be two notes and nodes are very +important and so when we're we're going + + align:start position:0% +important and so when we're we're going + + + align:start position:0% +important and so when we're we're going +to be dealing with cartoons of the wave + + align:start position:0% +to be dealing with cartoons of the wave + + + align:start position:0% +to be dealing with cartoons of the wave +function and then using semi classical + + align:start position:0% +function and then using semi classical + + + align:start position:0% +function and then using semi classical +ideas to actually semi calculate things + + align:start position:0% +ideas to actually semi calculate things + + + align:start position:0% +ideas to actually semi calculate things +you'd want to know that the nodes are + + align:start position:0% +you'd want to know that the nodes are + + + align:start position:0% +you'd want to know that the nodes are +really important okay and what's going + + align:start position:0% +really important okay and what's going + + + align:start position:0% +really important okay and what's going +to happen on Monday is we'll throw away + + align:start position:0% +to happen on Monday is we'll throw away + + + align:start position:0% +to happen on Monday is we'll throw away +all this garbage and we will replace + + align:start position:0% +all this garbage and we will replace + + + align:start position:0% +all this garbage and we will replace +everything by these creation and + + align:start position:0% +everything by these creation and + + + align:start position:0% +everything by these creation and +annihilation operators which do have + + align:start position:0% +annihilation operators which do have + + + align:start position:0% +annihilation operators which do have +really simple problem properties which + + align:start position:0% +really simple problem properties which + + + align:start position:0% +really simple problem properties which +you can use to do astonishingly + + align:start position:0% +you can use to do astonishingly + + + align:start position:0% +you can use to do astonishingly +complicated things without breaking a + + align:start position:0% +complicated things without breaking a + + + align:start position:0% +complicated things without breaking a +sweat + + align:start position:0% +sweat + + + align:start position:0% +sweat +okay so and the final exam is in this + + align:start position:0% +okay so and the final exam is in this + + + align:start position:0% +okay so and the final exam is in this +room on the first day of exam period at + + align:start position:0% +room on the first day of exam period at + + + align:start position:0% +room on the first day of exam period at +least it's not on Monday and it's in the + + align:start position:0% +least it's not on Monday and it's in the + + + align:start position:0% +least it's not on Monday and it's in the +afternoon + + align:start position:0% + + + + align:start position:0% + +okay in the non lecture part of the + + align:start position:0% +okay in the non lecture part of the + + + align:start position:0% +okay in the non lecture part of the +notes I replace the mass for one mass on + + align:start position:0% +notes I replace the mass for one mass on + + + align:start position:0% +notes I replace the mass for one mass on +a spring by the reduced mass which is m1 + + align:start position:0% +a spring by the reduced mass which is m1 + + + align:start position:0% +a spring by the reduced mass which is m1 +m2 over m1 plus m2 for two masses + + align:start position:0% +m2 over m1 plus m2 for two masses + + + align:start position:0% +m2 over m1 plus m2 for two masses +connected by a spring and so I go back + + align:start position:0% +connected by a spring and so I go back + + + align:start position:0% +connected by a spring and so I go back +and forth B to Z between using mu n m + + align:start position:0% +and forth B to Z between using mu n m + + + align:start position:0% +and forth B to Z between using mu n m +and that's okay all right so in the + + align:start position:0% +and that's okay all right so in the + + + align:start position:0% +and that's okay all right so in the +notes the differential equations in the + + align:start position:0% +notes the differential equations in the + + + align:start position:0% +notes the differential equations in the +first few pages are expressed as partial + + align:start position:0% +first few pages are expressed as partial + + + align:start position:0% +first few pages are expressed as partial +differential equations there are total + + align:start position:0% +differential equations there are total + + + align:start position:0% +differential equations there are total +differential equations so that'll get + + align:start position:0% +differential equations so that'll get + + + align:start position:0% +differential equations so that'll get +changed but so the Hamiltonian is P plus + + align:start position:0% +changed but so the Hamiltonian is P plus + + + align:start position:0% +changed but so the Hamiltonian is P plus +e and in the usual form T is P squared + + align:start position:0% +e and in the usual form T is P squared + + + align:start position:0% +e and in the usual form T is P squared +over 2 mu and so we get minus h-bar over + + align:start position:0% +over 2 mu and so we get minus h-bar over + + + align:start position:0% +over 2 mu and so we get minus h-bar over +2 mu are not partial I'm so used to + + align:start position:0% +2 mu are not partial I'm so used to + + + align:start position:0% +2 mu are not partial I'm so used to +writing partials that I can't stop + + align:start position:0% +writing partials that I can't stop + + + align:start position:0% +writing partials that I can't stop +second derivative with respect X plus + + align:start position:0% +second derivative with respect X plus + + + align:start position:0% +second derivative with respect X plus +1/2 okay so that's the Hamiltonian now + + align:start position:0% +1/2 okay so that's the Hamiltonian now + + + align:start position:0% +1/2 okay so that's the Hamiltonian now +that looks kind of innocent but it isn't + + align:start position:0% +that looks kind of innocent but it isn't + + + align:start position:0% +that looks kind of innocent but it isn't +and so the first thing we want to do is + + align:start position:0% +and so the first thing we want to do is + + + align:start position:0% +and so the first thing we want to do is +get rid of the dimensionality the units + + align:start position:0% +get rid of the dimensionality the units + + + align:start position:0% +get rid of the dimensionality the units +so this is X I and it's defined as + + align:start position:0% +so this is X I and it's defined as + + + align:start position:0% +so this is X I and it's defined as +square root of alpha times X where alpha + + align:start position:0% +square root of alpha times X where alpha + + + align:start position:0% +square root of alpha times X where alpha +is defined as K mu square root over + + align:start position:0% +is defined as K mu square root over + + + align:start position:0% +is defined as K mu square root over +h-bar now it would be a perfectly + + align:start position:0% +h-bar now it would be a perfectly + + + align:start position:0% +h-bar now it would be a perfectly +reasonable exam question for you to + + align:start position:0% +reasonable exam question for you to + + + align:start position:0% +reasonable exam question for you to +prove that if I take this combination of + + align:start position:0% +prove that if I take this combination of + + + align:start position:0% +prove that if I take this combination of +physical quoi + + align:start position:0% +physical quoi + + + align:start position:0% +physical quoi +this will have dimension of one over + + align:start position:0% +this will have dimension of one over + + + align:start position:0% +this will have dimension of one over +length so that makes psy dimensionless + + align:start position:0% +length so that makes psy dimensionless + + + align:start position:0% +length so that makes psy dimensionless +quantity so I'm not even going to bother + + align:start position:0% +quantity so I'm not even going to bother + + + align:start position:0% +quantity so I'm not even going to bother +going through the derivation the + + align:start position:0% +going through the derivation the + + + align:start position:0% +going through the derivation the +Hamiltonian becomes H bar Omega times + + align:start position:0% +Hamiltonian becomes H bar Omega times + + + align:start position:0% +Hamiltonian becomes H bar Omega times +two minus second derivative with respect + + align:start position:0% +two minus second derivative with respect + + + align:start position:0% +two minus second derivative with respect +to sine plus y squared alright so this + + align:start position:0% +to sine plus y squared alright so this + + + align:start position:0% +to sine plus y squared alright so this +is now a and now this is dimensionless + + align:start position:0% +is now a and now this is dimensionless + + + align:start position:0% +is now a and now this is dimensionless +this has units we divide by H bar Omega + + align:start position:0% +this has units we divide by H bar Omega + + + align:start position:0% +this has units we divide by H bar Omega +to make now everything dimensionless and + + align:start position:0% +to make now everything dimensionless and + + + align:start position:0% +to make now everything dimensionless and +we get a differential equation that has + + align:start position:0% +we get a differential equation that has + + + align:start position:0% +we get a differential equation that has +the form second - the second derivative + + align:start position:0% +the form second - the second derivative + + + align:start position:0% +the form second - the second derivative +with respect + + align:start position:0% +with respect + + + align:start position:0% +with respect +psy plus size squared - 2 e over H bar + + align:start position:0% +psy plus size squared - 2 e over H bar + + + align:start position:0% +psy plus size squared - 2 e over H bar +Omega times the wave function expressed + + align:start position:0% +Omega times the wave function expressed + + + align:start position:0% +Omega times the wave function expressed +as function of because I X I naught X ok + + align:start position:0% +as function of because I X I naught X ok + + + align:start position:0% +as function of because I X I naught X ok +so this is the differential equation we + + align:start position:0% +so this is the differential equation we + + + align:start position:0% +so this is the differential equation we +want to solve and we don't do that in + + align:start position:0% +want to solve and we don't do that in + + + align:start position:0% +want to solve and we don't do that in +561 you're never going to be asked to + + align:start position:0% +561 you're never going to be asked to + + + align:start position:0% +561 you're never going to be asked to +solve a differential equation like this + + align:start position:0% +solve a differential equation like this + + + align:start position:0% +solve a differential equation like this +but you're certainly going to be asked + + align:start position:0% +but you're certainly going to be asked + + + align:start position:0% +but you're certainly going to be asked +to understand what the solution looks + + align:start position:0% +to understand what the solution looks + + + align:start position:0% +to understand what the solution looks +like and perhaps that it is in fact a + + align:start position:0% +like and perhaps that it is in fact a + + + align:start position:0% +like and perhaps that it is in fact a +solution but that's still pretty high + + align:start position:0% +solution but that's still pretty high + + + align:start position:0% +solution but that's still pretty high +value stuff so you wouldn't really have + + align:start position:0% +value stuff so you wouldn't really have + + + align:start position:0% +value stuff so you wouldn't really have +to do that so this is the simplest way + + align:start position:0% +to do that so this is the simplest way + + + align:start position:0% +to do that so this is the simplest way +of writing the differential equation and + + align:start position:0% +of writing the differential equation and + + + align:start position:0% +of writing the differential equation and +it's dimensionless ok the standard way + + align:start position:0% +it's dimensionless ok the standard way + + + align:start position:0% +it's dimensionless ok the standard way +of dealing with many differential + + align:start position:0% +of dealing with many differential + + + align:start position:0% +of dealing with many differential +equations is to say ok we have some + + align:start position:0% +equations is to say ok we have some + + + align:start position:0% +equations is to say ok we have some +function and it's going to be written as + + align:start position:0% +function and it's going to be written as + + + align:start position:0% +function and it's going to be written as +a + + align:start position:0% + + + + align:start position:0% + +exponential a Gaussian times some new + + align:start position:0% +exponential a Gaussian times some new + + + align:start position:0% +exponential a Gaussian times some new +function and for quantum mechanics this + + align:start position:0% +function and for quantum mechanics this + + + align:start position:0% +function and for quantum mechanics this +is perfectly reasonable because we have + + align:start position:0% +is perfectly reasonable because we have + + + align:start position:0% +is perfectly reasonable because we have +a function in a well and the wave + + align:start position:0% +a function in a well and the wave + + + align:start position:0% +a function in a well and the wave +functions have to go to zero at plus and + + align:start position:0% +functions have to go to zero at plus and + + + align:start position:0% +functions have to go to zero at plus and +minus infinity and this thing goes to 0 + + align:start position:0% +minus infinity and this thing goes to 0 + + + align:start position:0% +minus infinity and this thing goes to 0 +at plus and minus infinity pretty + + align:start position:0% +at plus and minus infinity pretty + + + align:start position:0% +at plus and minus infinity pretty +strongly so it's a good way of building + + align:start position:0% +strongly so it's a good way of building + + + align:start position:0% +strongly so it's a good way of building +in some of the expected behavior of the + + align:start position:0% +in some of the expected behavior of the + + + align:start position:0% +in some of the expected behavior of the +solution and that's perfectly legal and + + align:start position:0% +solution and that's perfectly legal and + + + align:start position:0% +solution and that's perfectly legal and +it just then defines what is the + + align:start position:0% +it just then defines what is the + + + align:start position:0% +it just then defines what is the +difference of the equation remaining for + + align:start position:0% +difference of the equation remaining for + + + align:start position:0% +difference of the equation remaining for +this and it turns out well we're going + + align:start position:0% +this and it turns out well we're going + + + align:start position:0% +this and it turns out well we're going +to get a the Hermit equation and this + + align:start position:0% +to get a the Hermit equation and this + + + align:start position:0% +to get a the Hermit equation and this +will be a hermit polynomial the + + align:start position:0% +will be a hermit polynomial the + + + align:start position:0% +will be a hermit polynomial the +solutions okay now one way of dealing + + align:start position:0% +solutions okay now one way of dealing + + + align:start position:0% +solutions okay now one way of dealing +with this is is to simply say well we + + align:start position:0% +with this is is to simply say well we + + + align:start position:0% +with this is is to simply say well we +know the solution of this differential + + align:start position:0% +know the solution of this differential + + + align:start position:0% +know the solution of this differential +equation if this term weren't there okay + + align:start position:0% +equation if this term weren't there okay + + + align:start position:0% +equation if this term weren't there okay +because this is now how the equation for + + align:start position:0% +because this is now how the equation for + + + align:start position:0% +because this is now how the equation for +a Gaussian so building in a Gaussian as + + align:start position:0% +a Gaussian so building in a Gaussian as + + + align:start position:0% +a Gaussian so building in a Gaussian as +a factor in the solution it's a + + align:start position:0% +a factor in the solution it's a + + + align:start position:0% +a factor in the solution it's a +perfectly reasonable thing and then we + + align:start position:0% +perfectly reasonable thing and then we + + + align:start position:0% +perfectly reasonable thing and then we +have to say okay what happens now when + + align:start position:0% +have to say okay what happens now when + + + align:start position:0% +have to say okay what happens now when +we put this term back in and when we do + + align:start position:0% +we put this term back in and when we do + + + align:start position:0% +we put this term back in and when we do +we get this thing second derivative with + + align:start position:0% +we get this thing second derivative with + + + align:start position:0% +we get this thing second derivative with +respect to this polynomial of this + + align:start position:0% +respect to this polynomial of this + + + align:start position:0% +respect to this polynomial of this +polynomial is equal to minus 2 sy times + + align:start position:0% + + + + align:start position:0% + +X I plus 2 and H n so this is a famous + + align:start position:0% +X I plus 2 and H n so this is a famous + + + align:start position:0% +X I plus 2 and H n so this is a famous +differential equation the Hermit + + align:start position:0% +differential equation the Hermit + + + align:start position:0% +differential equation the Hermit +equation which is of no interest does + + align:start position:0% + + + + align:start position:0% + +and it generates the Hermit polynomials + + align:start position:0% +and it generates the Hermit polynomials + + + align:start position:0% +and it generates the Hermit polynomials +these things are the Hermit polynomials + + align:start position:0% + + + + align:start position:0% + +and they're treated as in some kind of + + align:start position:0% +and they're treated as in some kind of + + + align:start position:0% +and they're treated as in some kind of +sacred manner in most of the textbooks + + align:start position:0% +sacred manner in most of the textbooks + + + align:start position:0% +sacred manner in most of the textbooks +and I think that's really an offense + + align:start position:0% +and I think that's really an offense + + + align:start position:0% +and I think that's really an offense +because well we're not interested in + + align:start position:0% +because well we're not interested in + + + align:start position:0% +because well we're not interested in +mathematical functions we're we're + + align:start position:0% +mathematical functions we're we're + + + align:start position:0% +mathematical functions we're we're +interested in insight and this is just + + align:start position:0% +interested in insight and this is just + + + align:start position:0% +interested in insight and this is just +putting up another barrier so now these + + align:start position:0% +putting up another barrier so now these + + + align:start position:0% +putting up another barrier so now these +with this equation you can derive two + + align:start position:0% +with this equation you can derive two + + + align:start position:0% +with this equation you can derive two +things called recursion relations and + + align:start position:0% +things called recursion relations and + + + align:start position:0% +things called recursion relations and +one of them is the derivative of this + + align:start position:0% +one of them is the derivative of this + + + align:start position:0% +one of them is the derivative of this +polynomial with respect to X I is equal + + align:start position:0% +polynomial with respect to X I is equal + + + align:start position:0% +polynomial with respect to X I is equal +to 2 n times H and minus one obscure + + align:start position:0% +to 2 n times H and minus one obscure + + + align:start position:0% +to 2 n times H and minus one obscure +side now that's not a surprise + + align:start position:0% +side now that's not a surprise + + + align:start position:0% +side now that's not a surprise +because this is a polynomial and if you + + align:start position:0% +because this is a polynomial and if you + + + align:start position:0% +because this is a polynomial and if you +take a derivative of the variable you're + + align:start position:0% +take a derivative of the variable you're + + + align:start position:0% +take a derivative of the variable you're +going to reduce the power of each term + + align:start position:0% +going to reduce the power of each term + + + align:start position:0% +going to reduce the power of each term +by one now it just happens to be lucky + + align:start position:0% +by one now it just happens to be lucky + + + align:start position:0% +by one now it just happens to be lucky +that we're going to reduce it to one you + + align:start position:0% +that we're going to reduce it to one you + + + align:start position:0% +that we're going to reduce it to one you +don't get a sum of many different lower + + align:start position:0% +don't get a sum of many different lower + + + align:start position:0% +don't get a sum of many different lower +order polynomials you just get one and + + align:start position:0% +order polynomials you just get one and + + + align:start position:0% +order polynomials you just get one and +there's another one another recursive + + align:start position:0% +there's another one another recursive + + + align:start position:0% +there's another one another recursive +relation where it tells you if you want + + align:start position:0% +relation where it tells you if you want + + + align:start position:0% +relation where it tells you if you want +to increase the order you can do this + + align:start position:0% +to increase the order you can do this + + + align:start position:0% +to increase the order you can do this +you can multiply H n bikes I and that's + + align:start position:0% +you can multiply H n bikes I and that's + + + align:start position:0% +you can multiply H n bikes I and that's +obviously it is going to increase the + + align:start position:0% +obviously it is going to increase the + + + align:start position:0% +obviously it is going to increase the +order but it might not do it cleanly and + + align:start position:0% +order but it might not do it cleanly and + + + align:start position:0% +order but it might not do it cleanly and +it doesn't and so we get so we have a + + align:start position:0% + + + + align:start position:0% + +relationship between these three + + align:start position:0% +relationship between these three + + + align:start position:0% +relationship between these three +different polynomials ok now it turns + + align:start position:0% +different polynomials ok now it turns + + + align:start position:0% +different polynomials ok now it turns +out that these two equations are going + + align:start position:0% +out that these two equations are going + + + align:start position:0% +out that these two equations are going +to reappear or at least their progeny + + align:start position:0% +to reappear or at least their progeny + + + align:start position:0% +to reappear or at least their progeny +will reappear on Monday into + + align:start position:0% +will reappear on Monday into + + + align:start position:0% +will reappear on Monday into +terms of raising and lowering operators + + align:start position:0% +terms of raising and lowering operators + + + align:start position:0% +terms of raising and lowering operators +and what you into it about what happens + + align:start position:0% +and what you into it about what happens + + + align:start position:0% +and what you into it about what happens +if you multiply a polynomial by the + + align:start position:0% +if you multiply a polynomial by the + + + align:start position:0% +if you multiply a polynomial by the +variable or what happens if you take its + + align:start position:0% +variable or what happens if you take its + + + align:start position:0% +variable or what happens if you take its +derivative and it is very simple and + + align:start position:0% +derivative and it is very simple and + + + align:start position:0% +derivative and it is very simple and +beautiful but I don't think this is very + + align:start position:0% +beautiful but I don't think this is very + + + align:start position:0% +beautiful but I don't think this is very +beautiful for our purposes at chemists + + align:start position:0% +beautiful for our purposes at chemists + + + align:start position:0% +beautiful for our purposes at chemists +and one of the things that these + + align:start position:0% +and one of the things that these + + + align:start position:0% +and one of the things that these +recursion relationships do which also + + align:start position:0% +recursion relationships do which also + + + align:start position:0% +recursion relationships do which also +hints at what's to come on Monday is it + + align:start position:0% +hints at what's to come on Monday is it + + + align:start position:0% +hints at what's to come on Monday is it +we can calculate integrals like this no + + align:start position:0% +we can calculate integrals like this no + + + align:start position:0% +we can calculate integrals like this no +that's not what I want this is a quantum + + align:start position:0% +that's not what I want this is a quantum + + + align:start position:0% +that's not what I want this is a quantum +number it's an integer it's V not new + + align:start position:0% +number it's an integer it's V not new + + + align:start position:0% +number it's an integer it's V not new +and multiplied by X to the N P to the M + + align:start position:0% +and multiplied by X to the N P to the M + + + align:start position:0% +and multiplied by X to the N P to the M +sy conjugated V Plus L Y X it turns out + + align:start position:0% +sy conjugated V Plus L Y X it turns out + + + align:start position:0% +sy conjugated V Plus L Y X it turns out +for almost everything we want to do with + + align:start position:0% +for almost everything we want to do with + + + align:start position:0% +for almost everything we want to do with +harmonic oscillators we're going to want + + align:start position:0% +harmonic oscillators we're going to want + + + align:start position:0% +harmonic oscillators we're going to want +to know a lot of integrals like this + + align:start position:0% + + + + align:start position:0% + +one of the things we like is when an + + align:start position:0% +one of the things we like is when an + + + align:start position:0% +one of the things we like is when an +integral is promised to be zero so we + + align:start position:0% +integral is promised to be zero so we + + + align:start position:0% +integral is promised to be zero so we +don't ever have to look at it and so + + align:start position:0% +don't ever have to look at it and so + + + align:start position:0% +don't ever have to look at it and so +their selection rules and the selection + + align:start position:0% +their selection rules and the selection + + + align:start position:0% +their selection rules and the selection +rules for the this kind of integral is L + + align:start position:0% +rules for the this kind of integral is L + + + align:start position:0% +rules for the this kind of integral is L +is equal to M plus n m plus n minus 2 + + align:start position:0% +is equal to M plus n m plus n minus 2 + + + align:start position:0% +is equal to M plus n m plus n minus 2 +down to minus M plus n so the only + + align:start position:0% +down to minus M plus n so the only + + + align:start position:0% +down to minus M plus n so the only +possible nonzero integrals of this form + + align:start position:0% +possible nonzero integrals of this form + + + align:start position:0% +possible nonzero integrals of this form +are for the change in quantum number by + + align:start position:0% +are for the change in quantum number by + + + align:start position:0% +are for the change in quantum number by +this L which goes from M plus n down to + + align:start position:0% +this L which goes from M plus n down to + + + align:start position:0% +this L which goes from M plus n down to +minus M plus n in steps of 2 the two + + align:start position:0% +minus M plus n in steps of 2 the two + + + align:start position:0% +minus M plus n in steps of 2 the two +shouldn't be too surprising because + + align:start position:0% +shouldn't be too surprising because + + + align:start position:0% +shouldn't be too surprising because +their symmetry and we have odd functions + + align:start position:0% +their symmetry and we have odd functions + + + align:start position:0% +their symmetry and we have odd functions +for odd quantum numbers and even + + align:start position:0% +for odd quantum numbers and even + + + align:start position:0% +for odd quantum numbers and even +functions for even quantum numbers and + + align:start position:0% +functions for even quantum numbers and + + + align:start position:0% +functions for even quantum numbers and +so something like this is going to have + + align:start position:0% +so something like this is going to have + + + align:start position:0% +so something like this is going to have +a definite symmetry and it's going to + + align:start position:0% +a definite symmetry and it's going to + + + align:start position:0% +a definite symmetry and it's going to +change things within that within a + + align:start position:0% +change things within that within a + + + align:start position:0% +change things within that within a +symmetry and so it's going to change the + + align:start position:0% +symmetry and so it's going to change the + + + align:start position:0% +symmetry and so it's going to change the +selection rule in steps of 2 now you + + align:start position:0% +selection rule in steps of 2 now you + + + align:start position:0% +selection rule in steps of 2 now you +don't know what selection rules are for + + align:start position:0% +don't know what selection rules are for + + + align:start position:0% +don't know what selection rules are for +why you should get excited about these + + align:start position:0% +why you should get excited about these + + + align:start position:0% +why you should get excited about these +thirds of things but it's really nice to + + align:start position:0% +thirds of things but it's really nice to + + + align:start position:0% +thirds of things but it's really nice to +know that almost all the integrals you + + align:start position:0% +know that almost all the integrals you + + + align:start position:0% +know that almost all the integrals you +ever going to face for a particular + + align:start position:0% +ever going to face for a particular + + + align:start position:0% +ever going to face for a particular +problem are 0 and you can focus on a + + align:start position:0% +problem are 0 and you can focus on a + + + align:start position:0% +problem are 0 and you can focus on a +small number of nonzero ones and it just + + align:start position:0% +small number of nonzero ones and it just + + + align:start position:0% +small number of nonzero ones and it just +turns out that the nonzero ones have + + align:start position:0% +turns out that the nonzero ones have + + + align:start position:0% +turns out that the nonzero ones have +really simple values there also exists + + align:start position:0% +really simple values there also exists + + + align:start position:0% +really simple values there also exists +what's called a generating function + + align:start position:0% + + + + align:start position:0% + +which is the Rodrigues formula and that + + align:start position:0% +which is the Rodrigues formula and that + + + align:start position:0% +which is the Rodrigues formula and that +is the H M of sy is equal to minus 1 to + + align:start position:0% +is the H M of sy is equal to minus 1 to + + + align:start position:0% +is the H M of sy is equal to minus 1 to +the n e to the I squared second + + align:start position:0% +the n e to the I squared second + + + align:start position:0% +the n e to the I squared second +derivative + + align:start position:0% + + + + align:start position:0% + +eat the - sighs okay so we have one that + + align:start position:0% +eat the - sighs okay so we have one that + + + align:start position:0% +eat the - sighs okay so we have one that +has a positive exponent one has a + + align:start position:0% +has a positive exponent one has a + + + align:start position:0% +has a positive exponent one has a +negative exponent we have this so we + + align:start position:0% +negative exponent we have this so we + + + align:start position:0% +negative exponent we have this so we +could calculate any hermit polynomial + + align:start position:0% +could calculate any hermit polynomial + + + align:start position:0% +could calculate any hermit polynomial +using this formula which you will never + + align:start position:0% +using this formula which you will never + + + align:start position:0% +using this formula which you will never +do but it's treated with great fanfare + + align:start position:0% +do but it's treated with great fanfare + + + align:start position:0% +do but it's treated with great fanfare +in textbooks + + align:start position:0% +in textbooks + + + align:start position:0% +in textbooks +okay now the solution to the harmonic + + align:start position:0% +okay now the solution to the harmonic + + + align:start position:0% +okay now the solution to the harmonic +oscillator wave function in real units + + align:start position:0% +oscillator wave function in real units + + + align:start position:0% +oscillator wave function in real units +as opposed to dimensionless quantities + + align:start position:0% +as opposed to dimensionless quantities + + + align:start position:0% +as opposed to dimensionless quantities +is and I'm just writing this down + + align:start position:0% +is and I'm just writing this down + + + align:start position:0% +is and I'm just writing this down +because I never would ever think about + + align:start position:0% +because I never would ever think about + + + align:start position:0% +because I never would ever think about +it this way but I have to at least you + + align:start position:0% +it this way but I have to at least you + + + align:start position:0% +it this way but I have to at least you +know provide you with guidance so we + + align:start position:0% +know provide you with guidance so we + + + align:start position:0% +know provide you with guidance so we +have a factor two to the V again this is + + align:start position:0% +have a factor two to the V again this is + + + align:start position:0% +have a factor two to the V again this is +V now the reason I'm emphasize + + align:start position:0% +V now the reason I'm emphasize + + + align:start position:0% +V now the reason I'm emphasize +emphasizing this is it in all texts the + + align:start position:0% +emphasizing this is it in all texts the + + + align:start position:0% +emphasizing this is it in all texts the +quantum numbers are italicized and if + + align:start position:0% +quantum numbers are italicized and if + + + align:start position:0% +quantum numbers are italicized and if +you've thought it for of about it for a + + align:start position:0% +you've thought it for of about it for a + + + align:start position:0% +you've thought it for of about it for a +minute and I tell like V for mortals + + align:start position:0% +minute and I tell like V for mortals + + + align:start position:0% +minute and I tell like V for mortals +looks like a new it isn't quite I don't + + align:start position:0% +looks like a new it isn't quite I don't + + + align:start position:0% +looks like a new it isn't quite I don't +know what the difference is but if you + + align:start position:0% +know what the difference is but if you + + + align:start position:0% +know what the difference is but if you +have them side by side they are + + align:start position:0% +have them side by side they are + + + align:start position:0% +have them side by side they are +different and so a large number of + + align:start position:0% +different and so a large number of + + + align:start position:0% +different and so a large number of +people who should know better + + align:start position:0% +people who should know better + + + align:start position:0% +people who should know better +refer to the vibrational quantum number + + align:start position:0% +refer to the vibrational quantum number + + + align:start position:0% +refer to the vibrational quantum number +as nu which marks that person as well I + + align:start position:0% +as nu which marks that person as well I + + + align:start position:0% +as nu which marks that person as well I +won't say but it's not complimentary + + align:start position:0% +won't say but it's not complimentary + + + align:start position:0% +won't say but it's not complimentary +okay so we have this factor coming and + + align:start position:0% +okay so we have this factor coming and + + + align:start position:0% +okay so we have this factor coming and +it's in square root and that's a + + align:start position:0% +it's in square root and that's a + + + align:start position:0% +it's in square root and that's a +normalization factor we got another part + + align:start position:0% +normalization factor we got another part + + + align:start position:0% +normalization factor we got another part +of it alpha over pi to the 1/4 power + + align:start position:0% +of it alpha over pi to the 1/4 power + + + align:start position:0% +of it alpha over pi to the 1/4 power +so that's normalization then we have the + + align:start position:0% +so that's normalization then we have the + + + align:start position:0% +so that's normalization then we have the +hermite polynomial and you notice I've + + align:start position:0% +hermite polynomial and you notice I've + + + align:start position:0% +hermite polynomial and you notice I've +got sy back in here which is really a + + align:start position:0% +got sy back in here which is really a + + + align:start position:0% +got sy back in here which is really a +shame and we have + + align:start position:0% + + + + align:start position:0% + +so this is the general solution we have + + align:start position:0% +so this is the general solution we have + + + align:start position:0% +so this is the general solution we have +the exponentially damped function we + + align:start position:0% +the exponentially damped function we + + + align:start position:0% +the exponentially damped function we +have the polynomials these are all the + + align:start position:0% +have the polynomials these are all the + + + align:start position:0% +have the polynomials these are all the +actors that we're going to have to deal + + align:start position:0% +actors that we're going to have to deal + + + align:start position:0% +actors that we're going to have to deal +with and I promise you you will never + + align:start position:0% +with and I promise you you will never + + + align:start position:0% +with and I promise you you will never +use this unless you want to program a + + align:start position:0% +use this unless you want to program a + + + align:start position:0% +use this unless you want to program a +computer to calculate the wave functions + + align:start position:0% +computer to calculate the wave functions + + + align:start position:0% +computer to calculate the wave functions +for god knows what reason + + align:start position:0% + + + + align:start position:0% + +okay the quantum numbers V are 0 1 2 and + + align:start position:0% +okay the quantum numbers V are 0 1 2 and + + + align:start position:0% +okay the quantum numbers V are 0 1 2 and +for a harmonic oscillator which goes to + + align:start position:0% +for a harmonic oscillator which goes to + + + align:start position:0% +for a harmonic oscillator which goes to +infinity V goes to infinity 2 there's an + + align:start position:0% +infinity V goes to infinity 2 there's an + + + align:start position:0% +infinity V goes to infinity 2 there's an +infinite number of eigenfunctions of the + + align:start position:0% +infinite number of eigenfunctions of the + + + align:start position:0% +infinite number of eigenfunctions of the +quantum mechanical Hamiltonian of + + align:start position:0% +quantum mechanical Hamiltonian of + + + align:start position:0% +quantum mechanical Hamiltonian of +quantum mechanical harmonic oscillator + + align:start position:0% +quantum mechanical harmonic oscillator + + + align:start position:0% +quantum mechanical harmonic oscillator +so we have and the functions are + + align:start position:0% +so we have and the functions are + + + align:start position:0% +so we have and the functions are +normalized we have side plus and minus + + align:start position:0% +normalized we have side plus and minus + + + align:start position:0% +normalized we have side plus and minus +infinity goes to 0 we have sy V of 0 so + + align:start position:0% +infinity goes to 0 we have sy V of 0 so + + + align:start position:0% +infinity goes to 0 we have sy V of 0 so +this for all VI / wouldn't be there + + align:start position:0% + + + + align:start position:0% + +sy V is 0 for the derivative of side + + align:start position:0% +sy V is 0 for the derivative of side + + + align:start position:0% +sy V is 0 for the derivative of side +with respect to X at x equals 0 is 0 / + + align:start position:0% +with respect to X at x equals 0 is 0 / + + + align:start position:0% +with respect to X at x equals 0 is 0 / +even me so we have symmetric functions + + align:start position:0% + + + + align:start position:0% + +and we have the energy levels is equal + + align:start position:0% +and we have the energy levels is equal + + + align:start position:0% +and we have the energy levels is equal +to H bar Omega B plus 1/2 now this is H + + align:start position:0% +to H bar Omega B plus 1/2 now this is H + + + align:start position:0% +to H bar Omega B plus 1/2 now this is H +over 2 pi and this is nu times 2 pi the + + align:start position:0% +over 2 pi and this is nu times 2 pi the + + + align:start position:0% +over 2 pi and this is nu times 2 pi the +frequency times 2 pi so it could also be + + align:start position:0% +frequency times 2 pi so it could also be + + + align:start position:0% +frequency times 2 pi so it could also be +H nu I have trouble remembering when + + align:start position:0% +H nu I have trouble remembering when + + + align:start position:0% +H nu I have trouble remembering when +there's a 2pi involved okay + + align:start position:0% + + + + align:start position:0% + +and we have this wonderful thing it says + + align:start position:0% +and we have this wonderful thing it says + + + align:start position:0% +and we have this wonderful thing it says +if V prime is equal to V this integral + + align:start position:0% +if V prime is equal to V this integral + + + align:start position:0% +if V prime is equal to V this integral +is 1 it's normalized and a V prime is + + align:start position:0% +is 1 it's normalized and a V prime is + + + align:start position:0% +is 1 it's normalized and a V prime is +not equal to V it's 0 and that stems + + align:start position:0% +not equal to V it's 0 and that stems + + + align:start position:0% +not equal to V it's 0 and that stems +from a theorem I mentioned before is if + + align:start position:0% +from a theorem I mentioned before is if + + + align:start position:0% +from a theorem I mentioned before is if +you have two different two eigenvalues + + align:start position:0% +you have two different two eigenvalues + + + align:start position:0% +you have two different two eigenvalues +of the same hamiltonian eigenfunctions + + align:start position:0% +of the same hamiltonian eigenfunctions + + + align:start position:0% +of the same hamiltonian eigenfunctions +of the same hamiltonian and they belong + + align:start position:0% +of the same hamiltonian and they belong + + + align:start position:0% +of the same hamiltonian and they belong +to different values eigen values their + + align:start position:0% +to different values eigen values their + + + align:start position:0% +to different values eigen values their +overlap integral is 0 we like zeroes we + + align:start position:0% +overlap integral is 0 we like zeroes we + + + align:start position:0% +overlap integral is 0 we like zeroes we +like normalization because the integral + + align:start position:0% +like normalization because the integral + + + align:start position:0% +like normalization because the integral +is just 1 it goes away or the integral + + align:start position:0% +is just 1 it goes away or the integral + + + align:start position:0% +is just 1 it goes away or the integral +is 0 the whole thing goes away so that's + + align:start position:0% +is 0 the whole thing goes away so that's + + + align:start position:0% +is 0 the whole thing goes away so that's +really good ok so we call this that the + + align:start position:0% +really good ok so we call this that the + + + align:start position:0% +really good ok so we call this that the +set of these is orthonormal orthogonal + + align:start position:0% +set of these is orthonormal orthogonal + + + align:start position:0% +set of these is orthonormal orthogonal +and normalized and the orthonormal + + align:start position:0% +and normalized and the orthonormal + + + align:start position:0% +and normalized and the orthonormal +terminology is used a lot and in almost + + align:start position:0% +terminology is used a lot and in almost + + + align:start position:0% +terminology is used a lot and in almost +all quantum mechanical problems we like + + align:start position:0% +all quantum mechanical problems we like + + + align:start position:0% +all quantum mechanical problems we like +using an orthonormal set of functions to + + align:start position:0% +using an orthonormal set of functions to + + + align:start position:0% +using an orthonormal set of functions to +solve everything sometimes we have to do + + align:start position:0% +solve everything sometimes we have to do + + + align:start position:0% +solve everything sometimes we have to do +a little work to establish that and I'll + + align:start position:0% +a little work to establish that and I'll + + + align:start position:0% +a little work to establish that and I'll +show much later in the course how when + + align:start position:0% +show much later in the course how when + + + align:start position:0% +show much later in the course how when +you have functions that are not + + align:start position:0% +you have functions that are not + + + align:start position:0% +you have functions that are not +orthogonal you can and not normalize you + + align:start position:0% +orthogonal you can and not normalize you + + + align:start position:0% +orthogonal you can and not normalize you +can create a set of functions which are + + align:start position:0% +can create a set of functions which are + + + align:start position:0% +can create a set of functions which are +and this is something that a computer + + align:start position:0% +and this is something that a computer + + + align:start position:0% +and this is something that a computer +will do without breaking a sweat + + align:start position:0% + + + + align:start position:0% + +okay now we're back to my favorite topic + + align:start position:0% +okay now we're back to my favorite topic + + + align:start position:0% +okay now we're back to my favorite topic +semi-classical because it's really easy + + align:start position:0% +semi-classical because it's really easy + + + align:start position:0% +semi-classical because it's really easy +to understand not just to understand the + + align:start position:0% +to understand not just to understand the + + + align:start position:0% +to understand not just to understand the +harmonic oscillator but to use it in + + align:start position:0% +harmonic oscillator but to use it in + + + align:start position:0% +harmonic oscillator but to use it in +many problems so in classic mechanics + + align:start position:0% +many problems so in classic mechanics + + + align:start position:0% +many problems so in classic mechanics +the kinetic energy is e minus V of X or + + align:start position:0% +the kinetic energy is e minus V of X or + + + align:start position:0% +the kinetic energy is e minus V of X or +P squared over 2 mu and so we can derive + + align:start position:0% +P squared over 2 mu and so we can derive + + + align:start position:0% +P squared over 2 mu and so we can derive +an equation for P of X classical + + align:start position:0% +an equation for P of X classical + + + align:start position:0% +an equation for P of X classical +mechanically which is 2 at 2 mu e minus + + align:start position:0% +mechanically which is 2 at 2 mu e minus + + + align:start position:0% +mechanically which is 2 at 2 mu e minus +3 of X its crook'd + + align:start position:0% + + + + align:start position:0% + +so this is an extremely useful function + + align:start position:0% +so this is an extremely useful function + + + align:start position:0% +so this is an extremely useful function +it's not an operator it's a thing that + + align:start position:0% +it's not an operator it's a thing that + + + align:start position:0% +it's not an operator it's a thing that +we're going to use to make sense of + + align:start position:0% +we're going to use to make sense of + + + align:start position:0% +we're going to use to make sense of +everything but it's not an operator and + + align:start position:0% +everything but it's not an operator and + + + align:start position:0% +everything but it's not an operator and +so this is classic mechanics and then in + + align:start position:0% +so this is classic mechanics and then in + + + align:start position:0% +so this is classic mechanics and then in +quantum mechanics we know that mr. de + + align:start position:0% +quantum mechanics we know that mr. de + + + align:start position:0% +quantum mechanics we know that mr. de +Blois told us that the wave length is + + align:start position:0% +Blois told us that the wave length is + + + align:start position:0% +Blois told us that the wave length is +equal to H over P and we can generalize + + align:start position:0% +equal to H over P and we can generalize + + + align:start position:0% +equal to H over P and we can generalize +to say well maybe the wave length is a + + align:start position:0% +to say well maybe the wave length is a + + + align:start position:0% +to say well maybe the wave length is a +function of X for potential which is not + + align:start position:0% +function of X for potential which is not + + + align:start position:0% +function of X for potential which is not +constant and even though this is not an + + align:start position:0% +constant and even though this is not an + + + align:start position:0% +constant and even though this is not an +operator in quantum mechanics this is + + align:start position:0% +operator in quantum mechanics this is + + + align:start position:0% +operator in quantum mechanics this is +true that you can say the distance + + align:start position:0% +true that you can say the distance + + + align:start position:0% +true that you can say the distance +between consecutive nodes is lambda over + + align:start position:0% +between consecutive nodes is lambda over + + + align:start position:0% +between consecutive nodes is lambda over +2 and so we can use this node + + align:start position:0% +2 and so we can use this node + + + align:start position:0% +2 and so we can use this node +relationship to great advantage okay so + + align:start position:0% +relationship to great advantage okay so + + + align:start position:0% +relationship to great advantage okay so +for the pair of nodes closest to X we + + align:start position:0% +for the pair of nodes closest to X we + + + align:start position:0% +for the pair of nodes closest to X we +can use this to calculate the distance + + align:start position:0% +can use this to calculate the distance + + + align:start position:0% +can use this to calculate the distance +between them + + align:start position:0% + + + + align:start position:0% + +very valuable because I also want to + + align:start position:0% +very valuable because I also want to + + + align:start position:0% +very valuable because I also want to +mention something if you have an + + align:start position:0% +mention something if you have an + + + align:start position:0% +mention something if you have an +integrand which is rapidly oscillating + + align:start position:0% +integrand which is rapidly oscillating + + + align:start position:0% +integrand which is rapidly oscillating +or if you have to rapidly oscillating + + align:start position:0% +or if you have to rapidly oscillating + + + align:start position:0% +or if you have to rapidly oscillating +functions and you're multiplying them + + align:start position:0% +functions and you're multiplying them + + + align:start position:0% +functions and you're multiplying them +together that integral will accumulate + + align:start position:0% +together that integral will accumulate + + + align:start position:0% +together that integral will accumulate +to its final value where at the position + + align:start position:0% +to its final value where at the position + + + align:start position:0% +to its final value where at the position +where the two oscillating functions are + + align:start position:0% +where the two oscillating functions are + + + align:start position:0% +where the two oscillating functions are +oscillating at the same frequency + + align:start position:0% +oscillating at the same frequency + + + align:start position:0% +oscillating at the same frequency +that's the stationary phase point and + + align:start position:0% +that's the stationary phase point and + + + align:start position:0% +that's the stationary phase point and +this is also a wonderful thing because + + align:start position:0% +this is also a wonderful thing because + + + align:start position:0% +this is also a wonderful thing because +if you can figure out where the things + + align:start position:0% +if you can figure out where the things + + + align:start position:0% +if you can figure out where the things +you're multiplying together are + + align:start position:0% +you're multiplying together are + + + align:start position:0% +you're multiplying together are +oscillating at the same frequency your + + align:start position:0% +oscillating at the same frequency your + + + align:start position:0% +oscillating at the same frequency your +integral becomes a number no work ever + + align:start position:0% +integral becomes a number no work ever + + + align:start position:0% +integral becomes a number no work ever +and that's a useful thing okay so the + + align:start position:0% +and that's a useful thing okay so the + + + align:start position:0% +and that's a useful thing okay so the +stationary phase method enables you to + + align:start position:0% +stationary phase method enables you to + + + align:start position:0% +stationary phase method enables you to +use this in a really fantastic way and + + align:start position:0% +use this in a really fantastic way and + + + align:start position:0% +use this in a really fantastic way and +it's a little bit like fineman's path + + align:start position:0% +it's a little bit like fineman's path + + + align:start position:0% +it's a little bit like fineman's path +integral idea that you can calculate a + + align:start position:0% +integral idea that you can calculate a + + + align:start position:0% +integral idea that you can calculate a +complicated thing by evaluating a an + + align:start position:0% +complicated thing by evaluating a an + + + align:start position:0% +complicated thing by evaluating a an +integral over a convenient path as + + align:start position:0% +integral over a convenient path as + + + align:start position:0% +integral over a convenient path as +opposed to integrating over all space + + align:start position:0% +opposed to integrating over all space + + + align:start position:0% +opposed to integrating over all space +because everything that you care about + + align:start position:0% +because everything that you care about + + + align:start position:0% +because everything that you care about +comes from stationary phase quantum + + align:start position:0% +comes from stationary phase quantum + + + align:start position:0% +comes from stationary phase quantum +mechanics is full of oscillations + + align:start position:0% +mechanics is full of oscillations + + + align:start position:0% +mechanics is full of oscillations +classic annex doesn't have oscillations + + align:start position:0% +classic annex doesn't have oscillations + + + align:start position:0% +classic annex doesn't have oscillations +and the two meet at the stationary phase + + align:start position:0% +and the two meet at the stationary phase + + + align:start position:0% +and the two meet at the stationary phase +point okay so now we're going to use + + align:start position:0% +point okay so now we're going to use + + + align:start position:0% +point okay so now we're going to use +these ideas to calculate useful stuff + + align:start position:0% +these ideas to calculate useful stuff + + + align:start position:0% +these ideas to calculate useful stuff +for quantum mechanical vibrational wave + + align:start position:0% +for quantum mechanical vibrational wave + + + align:start position:0% +for quantum mechanical vibrational wave +functions so the shapes of Phi of X gets + + align:start position:0% +functions so the shapes of Phi of X gets + + + align:start position:0% +functions so the shapes of Phi of X gets +exponentially damped but it extends + + align:start position:0% + + + + align:start position:0% + +into the classically forbidden II less + + align:start position:0% +into the classically forbidden II less + + + align:start position:0% +into the classically forbidden II less +than V of X so the wave function if we + + align:start position:0% +than V of X so the wave function if we + + + align:start position:0% +than V of X so the wave function if we +have a potential and we have a wave + + align:start position:0% +have a potential and we have a wave + + + align:start position:0% +have a potential and we have a wave +function that wave function is going to + + align:start position:0% +function that wave function is going to + + + align:start position:0% +function that wave function is going to +not go to zero at the edge but it's + + align:start position:0% +not go to zero at the edge but it's + + + align:start position:0% +not go to zero at the edge but it's +going to have a tail and that tail goes + + align:start position:0% +going to have a tail and that tail goes + + + align:start position:0% +going to have a tail and that tail goes +to zero at infinity and so there's some + + align:start position:0% +to zero at infinity and so there's some + + + align:start position:0% +to zero at infinity and so there's some +amplitude in where the particle isn't + + align:start position:0% +amplitude in where the particle isn't + + + align:start position:0% +amplitude in where the particle isn't +allowed to be classically and that's + + align:start position:0% +allowed to be classically and that's + + + align:start position:0% +allowed to be classically and that's +what we're tunneling comes in and but + + align:start position:0% +what we're tunneling comes in and but + + + align:start position:0% +what we're tunneling comes in and but +the important thing the important + + align:start position:0% +the important thing the important + + + align:start position:0% +the important thing the important +insight is that there are no nodes in + + align:start position:0% +insight is that there are no nodes in + + + align:start position:0% +insight is that there are no nodes in +the classically forbidden region there + + align:start position:0% +the classically forbidden region there + + + align:start position:0% +the classically forbidden region there +is only exponential decay towards zero + + align:start position:0% +is only exponential decay towards zero + + + align:start position:0% +is only exponential decay towards zero +and if you've chosen the wrong value of + + align:start position:0% +and if you've chosen the wrong value of + + + align:start position:0% +and if you've chosen the wrong value of +the energy in other words in a place + + align:start position:0% +the energy in other words in a place + + + align:start position:0% +the energy in other words in a place +where there is no no eigen function the + + align:start position:0% +where there is no no eigen function the + + + align:start position:0% +where there is no no eigen function the +wave function in the classically + + align:start position:0% +wave function in the classically + + + align:start position:0% +wave function in the classically +forbidden region will usually go to + + align:start position:0% +forbidden region will usually go to + + + align:start position:0% +forbidden region will usually go to +infinity either over here or over here + + align:start position:0% +infinity either over here or over here + + + align:start position:0% +infinity either over here or over here +and says well it's clearly not a good + + align:start position:0% +and says well it's clearly not a good + + + align:start position:0% +and says well it's clearly not a good +function but there are no zero crossings + + align:start position:0% + + + + align:start position:0% + +it's oscillating in E greater than V of + + align:start position:0% +it's oscillating in E greater than V of + + + align:start position:0% +it's oscillating in E greater than V of +X the classically allowed region the + + align:start position:0% +X the classically allowed region the + + + align:start position:0% +X the classically allowed region the +number of nodes is V so we can have V + + align:start position:0% +number of nodes is V so we can have V + + + align:start position:0% +number of nodes is V so we can have V +equals zero function that just goes up + + align:start position:0% +equals zero function that just goes up + + + align:start position:0% +equals zero function that just goes up +and goes down no internal nodes vehicles + + align:start position:0% +and goes down no internal nodes vehicles + + + align:start position:0% +and goes down no internal nodes vehicles +want to crow who crosses zero right in + + align:start position:0% +want to crow who crosses zero right in + + + align:start position:0% +want to crow who crosses zero right in +the middle and we have the even oddness + + align:start position:0% +the middle and we have the even oddness + + + align:start position:0% +the middle and we have the even oddness +even V even function odd V odd function + + align:start position:0% +even V even function odd V odd function + + + align:start position:0% +even V even function odd V odd function +so for an even function you have a + + align:start position:0% +so for an even function you have a + + + align:start position:0% +so for an even function you have a +relative maximum at x equals zero and + + align:start position:0% +relative maximum at x equals zero and + + + align:start position:0% +relative maximum at x equals zero and +for an odd function you have a zero and + + align:start position:0% +for an odd function you have a zero and + + + align:start position:0% +for an odd function you have a zero and +the opposite for their derivatives + + align:start position:0% + + + + align:start position:0% + +so the outer lobes the ones on the ends + + align:start position:0% +so the outer lobes the ones on the ends + + + align:start position:0% +so the outer lobes the ones on the ends +just before the particle RIA encounters + + align:start position:0% +just before the particle RIA encounters + + + align:start position:0% +just before the particle RIA encounters +the classically classical wall you get + + align:start position:0% +the classically classical wall you get + + + align:start position:0% +the classically classical wall you get +the maximum amplitude and so you can you + + align:start position:0% +the maximum amplitude and so you can you + + + align:start position:0% +the maximum amplitude and so you can you +can draw cartoons which looks sort of + + align:start position:0% +can draw cartoons which looks sort of + + + align:start position:0% +can draw cartoons which looks sort of +like that there most of the valuable + + align:start position:0% +like that there most of the valuable + + + align:start position:0% +like that there most of the valuable +stuff is at the outer turning point and + + align:start position:0% +stuff is at the outer turning point and + + + align:start position:0% +stuff is at the outer turning point and +there's oscillations in between but + + align:start position:0% +there's oscillations in between but + + + align:start position:0% +there's oscillations in between but +often you really care about these two + + align:start position:0% +often you really care about these two + + + align:start position:0% +often you really care about these two +outer lobes that's a pretty good + + align:start position:0% +outer lobes that's a pretty good + + + align:start position:0% +outer lobes that's a pretty good +simplification now there's a nice + + align:start position:0% +simplification now there's a nice + + + align:start position:0% +simplification now there's a nice +picture in Macquarie on page 226 which + + align:start position:0% +picture in Macquarie on page 226 which + + + align:start position:0% +picture in Macquarie on page 226 which +shows especially for size squared that + + align:start position:0% +shows especially for size squared that + + + align:start position:0% +shows especially for size squared that +the nodes are pretty big but they're not + + align:start position:0% +the nodes are pretty big but they're not + + + align:start position:0% +the nodes are pretty big but they're not +as big for relatively low quantum + + align:start position:0% +as big for relatively low quantum + + + align:start position:0% +as big for relatively low quantum +numbers as I've implied but at really + + align:start position:0% +numbers as I've implied but at really + + + align:start position:0% +numbers as I've implied but at really +high quantum numbers we have a thing + + align:start position:0% +high quantum numbers we have a thing + + + align:start position:0% +high quantum numbers we have a thing +called the correspondence principle and + + align:start position:0% +called the correspondence principle and + + + align:start position:0% +called the correspondence principle and +in the correspondence principle says + + align:start position:0% +in the correspondence principle says + + + align:start position:0% +in the correspondence principle says +that quantum mechanics will do what + + align:start position:0% +that quantum mechanics will do what + + + align:start position:0% +that quantum mechanics will do what +classical mechanics does in the limit of + + align:start position:0% +classical mechanics does in the limit of + + + align:start position:0% +classical mechanics does in the limit of +high quantum numbers and in the limit of + + align:start position:0% +high quantum numbers and in the limit of + + + align:start position:0% +high quantum numbers and in the limit of +high quantum numbers essentially all the + + align:start position:0% +high quantum numbers essentially all the + + + align:start position:0% +high quantum numbers essentially all the +amplitude is at the turning points and + + align:start position:0% +amplitude is at the turning points and + + + align:start position:0% +amplitude is at the turning points and +in classical mechanics the particle is + + align:start position:0% +in classical mechanics the particle is + + + align:start position:0% +in classical mechanics the particle is +moving fast in the middle and stops and + + align:start position:0% +moving fast in the middle and stops and + + + align:start position:0% +moving fast in the middle and stops and +turns around and essentially all the + + align:start position:0% +turns around and essentially all the + + + align:start position:0% +turns around and essentially all the +amplitude is at the turning point so + + align:start position:0% +amplitude is at the turning point so + + + align:start position:0% +amplitude is at the turning point so +this is nice + + align:start position:0% + + + + align:start position:0% + +okay now we're getting into Bob ISM + + align:start position:0% +okay now we're getting into Bob ISM + + + align:start position:0% +okay now we're getting into Bob ISM +territory because I'm really going to + + align:start position:0% +territory because I'm really going to + + + align:start position:0% +territory because I'm really going to +show you how to calculate the whatever + + align:start position:0% +show you how to calculate the whatever + + + align:start position:0% +show you how to calculate the whatever +you need + + align:start position:0% +you need + + + align:start position:0% +you need +using these semi-classical ideas so we + + align:start position:0% + + + + align:start position:0% + +have the probability envelope psy star + + align:start position:0% +have the probability envelope psy star + + + align:start position:0% +have the probability envelope psy star +of X sine of X and we're gonna have both + + align:start position:0% +of X sine of X and we're gonna have both + + + align:start position:0% +of X sine of X and we're gonna have both +of these having the same quantum number + + align:start position:0% +of these having the same quantum number + + + align:start position:0% +of these having the same quantum number +DX so this is the probability of finding + + align:start position:0% +DX so this is the probability of finding + + + align:start position:0% +DX so this is the probability of finding +the particle near X in a region of width + + align:start position:0% +the particle near X in a region of width + + + align:start position:0% +the particle near X in a region of width +DX + + align:start position:0% + + + + align:start position:0% + +and this is the same thing as DX over V + + align:start position:0% +and this is the same thing as DX over V + + + align:start position:0% +and this is the same thing as DX over V +classical it's not the same thing + + align:start position:0% +classical it's not the same thing + + + align:start position:0% +classical it's not the same thing +there's a constant here sorry so this + + align:start position:0% +there's a constant here sorry so this + + + align:start position:0% +there's a constant here sorry so this +probability density that you want is + + align:start position:0% +probability density that you want is + + + align:start position:0% +probability density that you want is +basically 1 over the classical velocity + + align:start position:0% +basically 1 over the classical velocity + + + align:start position:0% +basically 1 over the classical velocity +and that was damage I demonstrated that + + align:start position:0% +and that was damage I demonstrated that + + + align:start position:0% +and that was damage I demonstrated that +when I walked across the room when I + + align:start position:0% +when I walked across the room when I + + + align:start position:0% +when I walked across the room when I +walked fast in the middle and slow on + + align:start position:0% +walked fast in the middle and slow on + + + align:start position:0% +walked fast in the middle and slow on +the outside and you get the probability + + align:start position:0% +the outside and you get the probability + + + align:start position:0% +the outside and you get the probability +you get this constant by saying ok how + + align:start position:0% +you get this constant by saying ok how + + + align:start position:0% +you get this constant by saying ok how +long did it take for me to go from one + + align:start position:0% +long did it take for me to go from one + + + align:start position:0% +long did it take for me to go from one +end to the other and comparing that how + + align:start position:0% +end to the other and comparing that how + + + align:start position:0% +end to the other and comparing that how +long it took for me to go in some + + align:start position:0% +long it took for me to go in some + + + align:start position:0% +long it took for me to go in some +differential position so you get this + + align:start position:0% +differential position so you get this + + + align:start position:0% +differential position so you get this +this constant in a simple way so be + + align:start position:0% +this constant in a simple way so be + + + align:start position:0% +this constant in a simple way so be +classical is equal to P classical over + + align:start position:0% +classical is equal to P classical over + + + align:start position:0% +classical is equal to P classical over +the mass or the MU but we know is a + + align:start position:0% +the mass or the MU but we know is a + + + align:start position:0% +the mass or the MU but we know is a +function for P classical so we have 1 + + align:start position:0% +function for P classical so we have 1 + + + align:start position:0% +function for P classical so we have 1 +over mu times 2 nu e minus V of X so we + + align:start position:0% +over mu times 2 nu e minus V of X so we + + + align:start position:0% +over mu times 2 nu e minus V of X so we +know the velocity everywhere and there's + + align:start position:0% +know the velocity everywhere and there's + + + align:start position:0% +know the velocity everywhere and there's +nothing terribly hard about figuring + + align:start position:0% +nothing terribly hard about figuring + + + align:start position:0% +nothing terribly hard about figuring +that out ok and now we want to know what + + align:start position:0% +that out ok and now we want to know what + + + align:start position:0% +that out ok and now we want to know what +this proportionality constant is and so + + align:start position:0% +this proportionality constant is and so + + + align:start position:0% +this proportionality constant is and so +for that we say by the time to go from X + + align:start position:0% +for that we say by the time to go from X + + + align:start position:0% +for that we say by the time to go from X +to X plus DX over the time to go from X + + align:start position:0% +to X plus DX over the time to go from X + + + align:start position:0% +to X plus DX over the time to go from X +minus 2x plus because what's happening + + align:start position:0% +minus 2x plus because what's happening + + + align:start position:0% +minus 2x plus because what's happening +the particle is going back and forth + + align:start position:0% +the particle is going back and forth + + + align:start position:0% +the particle is going back and forth +inside this well and so this is the time + + align:start position:0% +inside this well and so this is the time + + + align:start position:0% +inside this well and so this is the time +it takes to go one pass and this is the + + align:start position:0% +it takes to go one pass and this is the + + + align:start position:0% +it takes to go one pass and this is the +time it takes to go through the it + + align:start position:0% +time it takes to go through the it + + + align:start position:0% +time it takes to go through the it +region of interest and so this ratio is + + align:start position:0% +region of interest and so this ratio is + + + align:start position:0% +region of interest and so this ratio is +the probability + + align:start position:0% + + + + align:start position:0% + +okay and so we have the probability + + align:start position:0% +okay and so we have the probability + + + align:start position:0% +okay and so we have the probability +moving to the from from left turning + + align:start position:0% +moving to the from from left turning + + + align:start position:0% +moving to the from from left turning +point to right turning point and we want + + align:start position:0% +point to right turning point and we want + + + align:start position:0% +point to right turning point and we want +to know the probability in that interval + + align:start position:0% +to know the probability in that interval + + + align:start position:0% +to know the probability in that interval +and so that's just the x over the + + align:start position:0% +and so that's just the x over the + + + align:start position:0% +and so that's just the x over the +classical at X over tau order to because + + align:start position:0% +classical at X over tau order to because + + + align:start position:0% +classical at X over tau order to because +tau is the period and we have half of a + + align:start position:0% +tau is the period and we have half of a + + + align:start position:0% +tau is the period and we have half of a +period and so it's all together and so + + align:start position:0% +period and so it's all together and so + + + align:start position:0% +period and so it's all together and so +I'm just gonna skip a little step + + align:start position:0% +I'm just gonna skip a little step + + + align:start position:0% +I'm just gonna skip a little step +because it's taking too long so our side + + align:start position:0% +because it's taking too long so our side + + + align:start position:0% +because it's taking too long so our side +the X is equal to K over 2 pi squared e + + align:start position:0% + + + + align:start position:0% + +is V of X square us DX now so if we know + + align:start position:0% +is V of X square us DX now so if we know + + + align:start position:0% +is V of X square us DX now so if we know +the potential and we know the energy and + + align:start position:0% +the potential and we know the energy and + + + align:start position:0% +the potential and we know the energy and +we know the force constant well we can + + align:start position:0% +we know the force constant well we can + + + align:start position:0% +we know the force constant well we can +say well this is this is the probability + + align:start position:0% +say well this is this is the probability + + + align:start position:0% +say well this is this is the probability +and and so but this is this is the + + align:start position:0% +and and so but this is this is the + + + align:start position:0% +and and so but this is this is the +probability of the class of the + + align:start position:0% +probability of the class of the + + + align:start position:0% +probability of the class of the +semi-classical representation of sy star + + align:start position:0% +semi-classical representation of sy star + + + align:start position:0% +semi-classical representation of sy star +by DX and X now this is oscillating and + + align:start position:0% +by DX and X now this is oscillating and + + + align:start position:0% +by DX and X now this is oscillating and +this is not + + align:start position:0% + + + + align:start position:0% + +so what we really want to know + + align:start position:0% + + + + align:start position:0% + +here's here's the so if we have psystar + + align:start position:0% + + + + align:start position:0% + +oops slow down okay so this is + + align:start position:0% +oops slow down okay so this is + + + align:start position:0% +oops slow down okay so this is +oscillating and what we've calculated + + align:start position:0% +oscillating and what we've calculated + + + align:start position:0% +oscillating and what we've calculated +before is something that looks sort of + + align:start position:0% +before is something that looks sort of + + + align:start position:0% +before is something that looks sort of +like that + + align:start position:0% +like that + + + align:start position:0% +like that +and if we multiply by two we have a + + align:start position:0% +and if we multiply by two we have a + + + align:start position:0% +and if we multiply by two we have a +curve that goes through the maximum of + + align:start position:0% +curve that goes through the maximum of + + + align:start position:0% +curve that goes through the maximum of +all these oscillations so the envelopes + + align:start position:0% +all these oscillations so the envelopes + + + align:start position:0% +all these oscillations so the envelopes +I star psy has the form we've multiplied + + align:start position:0% +I star psy has the form we've multiplied + + + align:start position:0% +I star psy has the form we've multiplied +by two and so we end up getting two okay + + align:start position:0% +by two and so we end up getting two okay + + + align:start position:0% +by two and so we end up getting two okay +over pi square e times V of X square + + align:start position:0% +over pi square e times V of X square + + + align:start position:0% +over pi square e times V of X square +root now you might say well these are + + align:start position:0% +root now you might say well these are + + + align:start position:0% +root now you might say well these are +complicated functions why should I + + align:start position:0% +complicated functions why should I + + + align:start position:0% +complicated functions why should I +bother with them but if you wanted to + + align:start position:0% +bother with them but if you wanted to + + + align:start position:0% +bother with them but if you wanted to +anything starting from the correct + + align:start position:0% +anything starting from the correct + + + align:start position:0% +anything starting from the correct +solution to the harmonic oscillator + + align:start position:0% +solution to the harmonic oscillator + + + align:start position:0% +solution to the harmonic oscillator +using the hermite polynomials this is a + + align:start position:0% +using the hermite polynomials this is a + + + align:start position:0% +using the hermite polynomials this is a +whole lot more overhead notice also this + + align:start position:0% +whole lot more overhead notice also this + + + align:start position:0% +whole lot more overhead notice also this +is a function of X not X I + + align:start position:0% + + + + align:start position:0% + +so this is the overlap function + + align:start position:0% +so this is the overlap function + + + align:start position:0% +so this is the overlap function +it's the curve that it touches the + + align:start position:0% +it's the curve that it touches the + + + align:start position:0% +it's the curve that it touches the +maximum of all these things and it's + + align:start position:0% +maximum of all these things and it's + + + align:start position:0% +maximum of all these things and it's +very useful if you want to know the + + align:start position:0% +very useful if you want to know the + + + align:start position:0% +very useful if you want to know the +probability of finding the system + + align:start position:0% +probability of finding the system + + + align:start position:0% +probability of finding the system +anywhere okay and we get the node + + align:start position:0% +anywhere okay and we get the node + + + align:start position:0% +anywhere okay and we get the node +spacing from the equation H over give X + + align:start position:0% +spacing from the equation H over give X + + + align:start position:0% +spacing from the equation H over give X +and now here comes something really nice + + align:start position:0% + + + + align:start position:0% + +it's called the semi-classical + + align:start position:0% +it's called the semi-classical + + + align:start position:0% +it's called the semi-classical +quantization integral so if we have a + + align:start position:0% +quantization integral so if we have a + + + align:start position:0% +quantization integral so if we have a +any one dimensional potential and we're + + align:start position:0% +any one dimensional potential and we're + + + align:start position:0% +any one dimensional potential and we're +at some energy we'd like to be able to + + align:start position:0% +at some energy we'd like to be able to + + + align:start position:0% +at some energy we'd like to be able to +know how many levels are are at the + + align:start position:0% +know how many levels are are at the + + + align:start position:0% +know how many levels are are at the +energy that energy or below or where are + + align:start position:0% +energy that energy or below or where are + + + align:start position:0% +energy that energy or below or where are +the energy levels and we get that from + + align:start position:0% +the energy levels and we get that from + + + align:start position:0% +the energy levels and we get that from +this really incredible thing so we want + + align:start position:0% +this really incredible thing so we want + + + align:start position:0% +this really incredible thing so we want +to know that okay this is the difference + + align:start position:0% +to know that okay this is the difference + + + align:start position:0% +to know that okay this is the difference +between nodes right and now if we would + + align:start position:0% +between nodes right and now if we would + + + align:start position:0% +between nodes right and now if we would +like to know X minus 2x plus it's a + + align:start position:0% +like to know X minus 2x plus it's a + + + align:start position:0% +like to know X minus 2x plus it's a +matter we can replace lambda of X by H + + align:start position:0% +matter we can replace lambda of X by H + + + align:start position:0% +matter we can replace lambda of X by H +over P of X and so we get P of X that's + + align:start position:0% +over P of X and so we get P of X that's + + + align:start position:0% +over P of X and so we get P of X that's +that energy over H DX P DX that's called + + align:start position:0% +that energy over H DX P DX that's called + + + align:start position:0% +that energy over H DX P DX that's called +an action integral now I have to tell a + + align:start position:0% +an action integral now I have to tell a + + + align:start position:0% +an action integral now I have to tell a +little story when I was a senior at + + align:start position:0% +little story when I was a senior at + + + align:start position:0% +little story when I was a senior at +Amherst College we had a a oral exam for + + align:start position:0% +Amherst College we had a a oral exam for + + + align:start position:0% +Amherst College we had a a oral exam for +whether my thesis was going to be + + align:start position:0% +whether my thesis was going to be + + + align:start position:0% +whether my thesis was going to be +accepted or not + + align:start position:0% +accepted or not + + + align:start position:0% +accepted or not +and one of my examiner's asked me what + + align:start position:0% +and one of my examiner's asked me what + + + align:start position:0% +and one of my examiner's asked me what +is the unit of H well its energy times + + align:start position:0% +is the unit of H well its energy times + + + align:start position:0% +is the unit of H well its energy times +time and he wouldn't he wouldn't stop he + + align:start position:0% +time and he wouldn't he wouldn't stop he + + + align:start position:0% +time and he wouldn't he wouldn't stop he +said no it went something else + + align:start position:0% +said no it went something else + + + align:start position:0% +said no it went something else +it's called action momentum times + + align:start position:0% +it's called action momentum times + + + align:start position:0% +it's called action momentum times +position this is an action integral and + + align:start position:0% +position this is an action integral and + + + align:start position:0% +position this is an action integral and +so anyway that's just a story I we had + + align:start position:0% +so anyway that's just a story I we had + + + align:start position:0% +so anyway that's just a story I we had +spent a half an hour and I was damn + + align:start position:0% +spent a half an hour and I was damn + + + align:start position:0% +spent a half an hour and I was damn +stubborn I was not you know it was + + align:start position:0% +stubborn I was not you know it was + + + align:start position:0% +stubborn I was not you know it was +energy times time but that it's much + + align:start position:0% +energy times time but that it's much + + + align:start position:0% +energy times time but that it's much +more inside here and that's maybe why I + + align:start position:0% +more inside here and that's maybe why I + + + align:start position:0% +more inside here and that's maybe why I +got so excited about this sort of an + + align:start position:0% +got so excited about this sort of an + + + align:start position:0% +got so excited about this sort of an +integral ok so if we if we want to know + + align:start position:0% +integral ok so if we if we want to know + + + align:start position:0% +integral ok so if we if we want to know +if we have an eigenvalue this integral + + align:start position:0% +if we have an eigenvalue this integral + + + align:start position:0% +if we have an eigenvalue this integral +has to be equal to H over 2 times the + + align:start position:0% +has to be equal to H over 2 times the + + + align:start position:0% +has to be equal to H over 2 times the +number of nodes that's pretty simple and + + align:start position:0% +number of nodes that's pretty simple and + + + align:start position:0% +number of nodes that's pretty simple and +so we can adjust e to satisfy this or if + + align:start position:0% +so we can adjust e to satisfy this or if + + + align:start position:0% +so we can adjust e to satisfy this or if +we wanted to know how many energy levels + + align:start position:0% +we wanted to know how many energy levels + + + align:start position:0% +we wanted to know how many energy levels +are are at an energy below that energy + + align:start position:0% +are are at an energy below that energy + + + align:start position:0% +are are at an energy below that energy +we've chosen we evaluate this integral + + align:start position:0% +we've chosen we evaluate this integral + + + align:start position:0% +we've chosen we evaluate this integral +and we get a number like 13.5 well means + + align:start position:0% +and we get a number like 13.5 well means + + + align:start position:0% +and we get a number like 13.5 well means +there are 13 energy levels below that + + align:start position:0% +there are 13 energy levels below that + + + align:start position:0% +there are 13 energy levels below that +now often you want to know the density + + align:start position:0% +now often you want to know the density + + + align:start position:0% +now often you want to know the density +of states the number of energy levels + + align:start position:0% +of states the number of energy levels + + + align:start position:0% +of states the number of energy levels +per unit energy because that turns out + + align:start position:0% +per unit energy because that turns out + + + align:start position:0% +per unit energy because that turns out +to be the critical quantity in + + align:start position:0% +to be the critical quantity in + + + align:start position:0% +to be the critical quantity in +calculating many things you want to know + + align:start position:0% +calculating many things you want to know + + + align:start position:0% +calculating many things you want to know +and you can get that from the + + align:start position:0% +and you can get that from the + + + align:start position:0% +and you can get that from the +semi-classical quantization okay + + align:start position:0% +semi-classical quantization okay + + + align:start position:0% +semi-classical quantization okay +so we're close to the end I just want to + + align:start position:0% +so we're close to the end I just want to + + + align:start position:0% +so we're close to the end I just want to +say where we're going so we have + + align:start position:0% +say where we're going so we have + + + align:start position:0% +say where we're going so we have +classical pictures and I really really + + align:start position:0% +classical pictures and I really really + + + align:start position:0% +classical pictures and I really really +want you to think about these classical + + align:start position:0% +want you to think about these classical + + + align:start position:0% +want you to think about these classical +pictures and use them rather than + + align:start position:0% +pictures and use them rather than + + + align:start position:0% +pictures and use them rather than +thinking well I'm going to have my cell + + align:start position:0% +thinking well I'm going to have my cell + + + align:start position:0% +thinking well I'm going to have my cell +phone program to evaluate all these + + align:start position:0% +phone program to evaluate all these + + + align:start position:0% +phone program to evaluate all these +necessary stuff + + align:start position:0% +necessary stuff + + + align:start position:0% +necessary stuff +and there are certain things you want to + + align:start position:0% +and there are certain things you want to + + + align:start position:0% +and there are certain things you want to +remember about this semi-classical + + align:start position:0% +remember about this semi-classical + + + align:start position:0% +remember about this semi-classical +picture and now we have the ability to + + align:start position:0% +picture and now we have the ability to + + + align:start position:0% +picture and now we have the ability to +calculate an infinite number of + + align:start position:0% +calculate an infinite number of + + + align:start position:0% +calculate an infinite number of +integrals involving harmonic oscillator + + align:start position:0% +integrals involving harmonic oscillator + + + align:start position:0% +integrals involving harmonic oscillator +functions and certain operators well + + align:start position:0% +functions and certain operators well + + + align:start position:0% +functions and certain operators well +la-dee-da but why do we want them well + + align:start position:0% +la-dee-da but why do we want them well + + + align:start position:0% +la-dee-da but why do we want them well +one of the things we want is to be able + + align:start position:0% +one of the things we want is to be able + + + align:start position:0% +one of the things we want is to be able +to calculate the probability of a + + align:start position:0% +to calculate the probability of a + + + align:start position:0% +to calculate the probability of a +vibrational transition that's called a + + align:start position:0% +vibrational transition that's called a + + + align:start position:0% +vibrational transition that's called a +transition moment and that's an easy + + align:start position:0% +transition moment and that's an easy + + + align:start position:0% +transition moment and that's an easy +thing to calculate another thing we want + + align:start position:0% +thing to calculate another thing we want + + + align:start position:0% +thing to calculate another thing we want +to do is to say well Nature screwed up + + align:start position:0% +to do is to say well Nature screwed up + + + align:start position:0% +to do is to say well Nature screwed up +this oscillator isn't harmonic there's + + align:start position:0% +this oscillator isn't harmonic there's + + + align:start position:0% +this oscillator isn't harmonic there's +an anharmonic term and I would like to + + align:start position:0% +an anharmonic term and I would like to + + + align:start position:0% +an anharmonic term and I would like to +know what is the contribution of a + + align:start position:0% +know what is the contribution of a + + + align:start position:0% +know what is the contribution of a +constant times X cubed in the potential + + align:start position:0% +constant times X cubed in the potential + + + align:start position:0% +constant times X cubed in the potential +to the energy levels and that's called + + align:start position:0% +to the energy levels and that's called + + + align:start position:0% +to the energy levels and that's called +perturbation theory or I want to have + + align:start position:0% +perturbation theory or I want to have + + + align:start position:0% +perturbation theory or I want to have +many harmonic oscillators in a + + align:start position:0% +many harmonic oscillators in a + + + align:start position:0% +many harmonic oscillators in a +polyatomic molecule they talk to each + + align:start position:0% +polyatomic molecule they talk to each + + + align:start position:0% +polyatomic molecule they talk to each +other and I want to calculate the + + align:start position:0% +other and I want to calculate the + + + align:start position:0% +other and I want to calculate the +interaction how the interactions between + + align:start position:0% +interaction how the interactions between + + + align:start position:0% +interaction how the interactions between +these harmonic oscillators affect the + + align:start position:0% +these harmonic oscillators affect the + + + align:start position:0% +these harmonic oscillators affect the +energy level remember when we have a + + align:start position:0% +energy level remember when we have a + + + align:start position:0% +energy level remember when we have a +separable Hamiltonian we could just + + align:start position:0% +separable Hamiltonian we could just + + + align:start position:0% +separable Hamiltonian we could just +write the energy levels as the sum of + + align:start position:0% +write the energy levels as the sum of + + + align:start position:0% +write the energy levels as the sum of +the individual Hamilton and then there's + + align:start position:0% +the individual Hamilton and then there's + + + align:start position:0% +the individual Hamilton and then there's +coupling terms and we deal with those by + + align:start position:0% +coupling terms and we deal with those by + + + align:start position:0% +coupling terms and we deal with those by +perturbation theory so there's all sorts + + align:start position:0% +perturbation theory so there's all sorts + + + align:start position:0% +perturbation theory so there's all sorts +of wonderful things we do but we're + + align:start position:0% +of wonderful things we do but we're + + + align:start position:0% +of wonderful things we do but we're +going to consider these magical + + align:start position:0% +going to consider these magical + + + align:start position:0% +going to consider these magical +operators a creation and annihilation + + align:start position:0% +operators a creation and annihilation + + + align:start position:0% +operators a creation and annihilation +operator where a star a dagger operating + + align:start position:0% +operator where a star a dagger operating + + + align:start position:0% +operator where a star a dagger operating +on IV gives + + align:start position:0% + + + + align:start position:0% + +this current a V plus one times I 3 + 1 + + align:start position:0% +this current a V plus one times I 3 + 1 + + + align:start position:0% +this current a V plus one times I 3 + 1 ++ a dagger operating on V gives the + + align:start position:0% ++ a dagger operating on V gives the + + + align:start position:0% ++ a dagger operating on V gives the +square root of V of this right I mean a + + align:start position:0% +square root of V of this right I mean a + + + align:start position:0% +square root of V of this right I mean a +non Dagger gives v square but that's I + + align:start position:0% +non Dagger gives v square but that's I + + + align:start position:0% +non Dagger gives v square but that's I +the minus 1 and that X is equal to a + + align:start position:0% +the minus 1 and that X is equal to a + + + align:start position:0% +the minus 1 and that X is equal to a +plus a dagger times a constant and so + + align:start position:0% +plus a dagger times a constant and so + + + align:start position:0% +plus a dagger times a constant and so +all of a sudden we can evaluate all + + align:start position:0% +all of a sudden we can evaluate all + + + align:start position:0% +all of a sudden we can evaluate all +integrals involving X or powers of X or + + align:start position:0% +integrals involving X or powers of X or + + + align:start position:0% +integrals involving X or powers of X or +momento or powers of momentum without + + align:start position:0% +momento or powers of momentum without + + + align:start position:0% +momento or powers of momentum without +thinking without ever looking at a + + align:start position:0% +thinking without ever looking at a + + + align:start position:0% +thinking without ever looking at a +function and I guarantee you that this + + align:start position:0% +function and I guarantee you that this + + + align:start position:0% +function and I guarantee you that this +is embodied in the incredible amount of + + align:start position:0% +is embodied in the incredible amount of + + + align:start position:0% +is embodied in the incredible amount of +work done where we've presented almost + + align:start position:0% +work done where we've presented almost + + + align:start position:0% +work done where we've presented almost +every problem is a harmonic oscillator + + align:start position:0% +every problem is a harmonic oscillator + + + align:start position:0% +every problem is a harmonic oscillator +in disguise because these days and a + + align:start position:0% +in disguise because these days and a + + + align:start position:0% +in disguise because these days and a +daggers enable you to generate + + align:start position:0% +daggers enable you to generate + + + align:start position:0% +daggers enable you to generate +everything without ever converting from + + align:start position:0% +everything without ever converting from + + + align:start position:0% +everything without ever converting from +X to X I without ever looking at an + + align:start position:0% +X to X I without ever looking at an + + + align:start position:0% +X to X I without ever looking at an +integral it's all just a manipulation of + + align:start position:0% +integral it's all just a manipulation of + + + align:start position:0% +integral it's all just a manipulation of +algebra and it's not just convenient but + + align:start position:0% +algebra and it's not just convenient but + + + align:start position:0% +algebra and it's not just convenient but +there's insight and so this is what I + + align:start position:0% +there's insight and so this is what I + + + align:start position:0% +there's insight and so this is what I +want to convey that you will get + + align:start position:0% +want to convey that you will get + + + align:start position:0% +want to convey that you will get +tremendous insight so maybe maybe I sold + + align:start position:0% +tremendous insight so maybe maybe I sold + + + align:start position:0% +tremendous insight so maybe maybe I sold +you on semi-classical and I don't I + + align:start position:0% +you on semi-classical and I don't I + + + align:start position:0% +you on semi-classical and I don't I +don't apologize for that because that's + + align:start position:0% +don't apologize for that because that's + + + align:start position:0% +don't apologize for that because that's +very useful but the next lecture when + + align:start position:0% +very useful but the next lecture when + + + align:start position:0% +very useful but the next lecture when +you get the A's and a daggers it'll just + + align:start position:0% +you get the A's and a daggers it'll just + + + align:start position:0% +you get the A's and a daggers it'll just +knock your socks off ok that's it \ No newline at end of file diff --git a/NHedXxUO-Bg.txt b/NHedXxUO-Bg.txt new file mode 100644 index 0000000000000000000000000000000000000000..7eb80486ad6cbe03dc0e5bb93280c26469b2a520 --- /dev/null +++ b/NHedXxUO-Bg.txt @@ -0,0 +1,10803 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT open courseware continue + + align:start position:0% +will help MIT open courseware continue + + + align:start position:0% +will help MIT open courseware continue +to offer highquality educational + + align:start position:0% +to offer highquality educational + + + align:start position:0% +to offer highquality educational +resources for free to make a donation or + + align:start position:0% +resources for free to make a donation or + + + align:start position:0% +resources for free to make a donation or +to view additional materials from + + align:start position:0% +to view additional materials from + + + align:start position:0% +to view additional materials from +hundreds of MIT courses visit MIT open + + align:start position:0% +hundreds of MIT courses visit MIT open + + + align:start position:0% +hundreds of MIT courses visit MIT open +courseware at + + align:start position:0% + + + + align:start position:0% + +ocw.mit.edu the technical topic for for + + align:start position:0% +ocw.mit.edu the technical topic for for + + + align:start position:0% +ocw.mit.edu the technical topic for for +today we start I rushed right at the end + + align:start position:0% +today we start I rushed right at the end + + + align:start position:0% +today we start I rushed right at the end +a little bit about tangent and normal + + align:start position:0% +a little bit about tangent and normal + + + align:start position:0% +a little bit about tangent and normal +unit vectors and I'm going just to recap + + align:start position:0% +unit vectors and I'm going just to recap + + + align:start position:0% +unit vectors and I'm going just to recap +that quick + + align:start position:0% +that quick + + + align:start position:0% +that quick +and then we're going to go on really a + + align:start position:0% +and then we're going to go on really a + + + align:start position:0% +and then we're going to go on really a +review which of by review this is the + + align:start position:0% +review which of by review this is the + + + align:start position:0% +review which of by review this is the +sort of stuff that for the most part I'm + + align:start position:0% +sort of stuff that for the most part I'm + + + align:start position:0% +sort of stuff that for the most part I'm +sure you've seen in 801 physics and + + align:start position:0% +sure you've seen in 801 physics and + + + align:start position:0% +sure you've seen in 801 physics and +other physics you've had before and + + align:start position:0% +other physics you've had before and + + + align:start position:0% +other physics you've had before and +that's impulse linear momentum and + + align:start position:0% +that's impulse linear momentum and + + + align:start position:0% +that's impulse linear momentum and +impulse so that'll be a quick review and + + align:start position:0% +impulse so that'll be a quick review and + + + align:start position:0% +impulse so that'll be a quick review and +then the third subject is one that's + + align:start position:0% +then the third subject is one that's + + + align:start position:0% +then the third subject is one that's +much deeper and this is angular momentum + + align:start position:0% +much deeper and this is angular momentum + + + align:start position:0% +much deeper and this is angular momentum +and angular momentum with respect to + + align:start position:0% +and angular momentum with respect to + + + align:start position:0% +and angular momentum with respect to +moving points which you probably haven't + + align:start position:0% +moving points which you probably haven't + + + align:start position:0% +moving points which you probably haven't +encountered before so those are the + + align:start position:0% +encountered before so those are the + + + align:start position:0% +encountered before so those are the +those are the three topics for today + + align:start position:0% +those are the three topics for today + + + align:start position:0% +those are the three topics for today +let's get + + align:start position:0% + + + + align:start position:0% + +started so last + + align:start position:0% +started so last + + + align:start position:0% +started so last +time the piece that + + align:start position:0% +time the piece that + + + align:start position:0% +time the piece that +I rushed a bit is this notion of tangent + + align:start position:0% + + + + align:start position:0% + +and normal + + align:start position:0% + + + + align:start position:0% + +coordinates so I gave this had this + + align:start position:0% +coordinates so I gave this had this + + + align:start position:0% +coordinates so I gave this had this +example you're driving down the road + + align:start position:0% + + + + align:start position:0% + +you drunk or + + align:start position:0% + + + + align:start position:0% + +whatever and when you're at this point + + align:start position:0% +whatever and when you're at this point + + + align:start position:0% +whatever and when you're at this point +this point and this point I'd like to + + align:start position:0% +this point and this point I'd like to + + + align:start position:0% +this point and this point I'd like to +know what the accelerations are so I'll + + align:start position:0% +know what the accelerations are so I'll + + + align:start position:0% +know what the accelerations are so I'll +call these one two 3 and this curve Y is + + align:start position:0% +call these one two 3 and this curve Y is + + + align:start position:0% +call these one two 3 and this curve Y is +of the form some y of some f + + align:start position:0% +of the form some y of some f + + + align:start position:0% +of the form some y of some f +ofx and in this case it's a + + align:start position:0% +ofx and in this case it's a + + + align:start position:0% +ofx and in this case it's a +sinine + + align:start position:0% +sinine + + + align:start position:0% +sinine +KX and K a is what's known as wave + + align:start position:0% +KX and K a is what's known as wave + + + align:start position:0% +KX and K a is what's known as wave +number is 2 pi over the wavelength 2 pi + + align:start position:0% +number is 2 pi over the wavelength 2 pi + + + align:start position:0% +number is 2 pi over the wavelength 2 pi +over Lambda and the wavelength then is + + align:start position:0% +over Lambda and the wavelength then is + + + align:start position:0% +over Lambda and the wavelength then is +for example from here to + + align:start position:0% + + + + align:start position:0% + +here now the velocity I'm going pick a + + align:start position:0% +here now the velocity I'm going pick a + + + align:start position:0% +here now the velocity I'm going pick a +point here the velocity at any point we + + align:start position:0% +point here the velocity at any point we + + + align:start position:0% +point here the velocity at any point we +know is just the tangent to the path so + + align:start position:0% +know is just the tangent to the path so + + + align:start position:0% +know is just the tangent to the path so +this is the path and this is horizontal + + align:start position:0% +this is the path and this is horizontal + + + align:start position:0% +this is the path and this is horizontal +so you're driving driving down the road + + align:start position:0% +so you're driving driving down the road + + + align:start position:0% +so you're driving driving down the road +like + + align:start position:0% +like + + + align:start position:0% +like +this right that's what we're trying to + + align:start position:0% +this right that's what we're trying to + + + align:start position:0% +this right that's what we're trying to +do + + align:start position:0% +do + + + align:start position:0% +do +here the gravity is down into the board + + align:start position:0% +here the gravity is down into the board + + + align:start position:0% +here the gravity is down into the board +doesn't really come into into the + + align:start position:0% + + + + align:start position:0% + +problem so the + + align:start position:0% +problem so the + + + align:start position:0% +problem so the +velocity at any at any time the vector + + align:start position:0% +velocity at any at any time the vector + + + align:start position:0% +velocity at any at any time the vector +we could describe as a magnitude and a + + align:start position:0% +we could describe as a magnitude and a + + + align:start position:0% +we could describe as a magnitude and a +unit Vector we'll call UT which is the + + align:start position:0% +unit Vector we'll call UT which is the + + + align:start position:0% +unit Vector we'll call UT which is the +tangent unit vector and at any instant + + align:start position:0% +tangent unit vector and at any instant + + + align:start position:0% +tangent unit vector and at any instant +in time it's just aligned with the + + align:start position:0% +in time it's just aligned with the + + + align:start position:0% +in time it's just aligned with the +tangent to to the + + align:start position:0% +tangent to to the + + + align:start position:0% +tangent to to the +curve and its + + align:start position:0% +curve and its + + + align:start position:0% +curve and its +perpendicular uh partner is a normal + + align:start position:0% +perpendicular uh partner is a normal + + + align:start position:0% +perpendicular uh partner is a normal +unit Vector which it points inward on + + align:start position:0% +unit Vector which it points inward on + + + align:start position:0% +unit Vector which it points inward on +the curve and this would be unu + + align:start position:0% +the curve and this would be unu + + + align:start position:0% +the curve and this would be unu +n now we're interested in accelerations + + align:start position:0% +n now we're interested in accelerations + + + align:start position:0% +n now we're interested in accelerations +so we'll need to take a derivative of + + align:start position:0% +so we'll need to take a derivative of + + + align:start position:0% +so we'll need to take a derivative of +this but + + align:start position:0% + + + + align:start position:0% + +uh so let I was going to say put taking + + align:start position:0% +uh so let I was going to say put taking + + + align:start position:0% +uh so let I was going to say put taking +aside but I won't so the acceleration + + align:start position:0% +aside but I won't so the acceleration + + + align:start position:0% +aside but I won't so the acceleration +vector we have to take a derivative of + + align:start position:0% +vector we have to take a derivative of + + + align:start position:0% +vector we have to take a derivative of +this well it's a v do UT plus a v + + align:start position:0% +this well it's a v do UT plus a v + + + align:start position:0% +this well it's a v do UT plus a v +UT + + align:start position:0% +UT + + + align:start position:0% +UT +dot it's a unit vector and we've + + align:start position:0% +dot it's a unit vector and we've + + + align:start position:0% +dot it's a unit vector and we've +encountered this problem before because + + align:start position:0% +encountered this problem before because + + + align:start position:0% +encountered this problem before because +if this rotates the unit Vector has a + + align:start position:0% +if this rotates the unit Vector has a + + + align:start position:0% +if this rotates the unit Vector has a +nonzero derivative because of its + + align:start position:0% + + + + align:start position:0% + +rotation and the this derivative + + align:start position:0% +rotation and the this derivative + + + align:start position:0% +rotation and the this derivative +of the unit + + align:start position:0% + + + + align:start position:0% + +Vector is given + + align:start position:0% +Vector is given + + + align:start position:0% +Vector is given +by Theta + + align:start position:0% +by Theta + + + align:start position:0% +by Theta +dot u n hat now what's Theta dot + + align:start position:0% +dot u n hat now what's Theta dot + + + align:start position:0% +dot u n hat now what's Theta dot +well on this curve at any instant in + + align:start position:0% +well on this curve at any instant in + + + align:start position:0% +well on this curve at any instant in +time here's + + align:start position:0% +time here's + + + align:start position:0% +time here's +U can't draw arrows today here's your + + align:start position:0% +U can't draw arrows today here's your + + + align:start position:0% +U can't draw arrows today here's your +UT at any instant when you're traveling + + align:start position:0% +UT at any instant when you're traveling + + + align:start position:0% +UT at any instant when you're traveling +Along on a curve you are going around a + + align:start position:0% +Along on a curve you are going around a + + + align:start position:0% +Along on a curve you are going around a +circle of some radius we'll call row so + + align:start position:0% +circle of some radius we'll call row so + + + align:start position:0% +circle of some radius we'll call row so +there's some radius of curvature at any + + align:start position:0% +there's some radius of curvature at any + + + align:start position:0% +there's some radius of curvature at any +instant in + + align:start position:0% +instant in + + + align:start position:0% +instant in +time and that radius of as you drive + + align:start position:0% +time and that radius of as you drive + + + align:start position:0% +time and that radius of as you drive +along in little time delta T you go + + align:start position:0% +along in little time delta T you go + + + align:start position:0% +along in little time delta T you go +forward and amount + + align:start position:0% +forward and amount + + + align:start position:0% +forward and amount +row Theta + + align:start position:0% +row Theta + + + align:start position:0% +row Theta +dot is the velocity at which you're + + align:start position:0% +dot is the velocity at which you're + + + align:start position:0% +dot is the velocity at which you're +traveling tangent to the + + align:start position:0% +traveling tangent to the + + + align:start position:0% +traveling tangent to the +curve so this is an there's an angle in + + align:start position:0% +curve so this is an there's an angle in + + + align:start position:0% +curve so this is an there's an angle in +here so in here there's some Delta you + + align:start position:0% +here so in here there's some Delta you + + + align:start position:0% +here so in here there's some Delta you +advance some Delta Theta so r r Omega is + + align:start position:0% +advance some Delta Theta so r r Omega is + + + align:start position:0% +advance some Delta Theta so r r Omega is +a velocity right so row Theta dot is a + + align:start position:0% +a velocity right so row Theta dot is a + + + align:start position:0% +a velocity right so row Theta dot is a +velocity and that gives you this + + align:start position:0% +velocity and that gives you this + + + align:start position:0% +velocity and that gives you this +velocity magnitude B + + align:start position:0% + + + + align:start position:0% + +okay and we've gone through I'm not + + align:start position:0% +okay and we've gone through I'm not + + + align:start position:0% +okay and we've gone through I'm not +going to go through that little deriv + + align:start position:0% +going to go through that little deriv + + + align:start position:0% +going to go through that little deriv +that little argument before but the the + + align:start position:0% +that little argument before but the the + + + align:start position:0% +that little argument before but the the +change in direction of this unit Vector + + align:start position:0% +change in direction of this unit Vector + + + align:start position:0% +change in direction of this unit Vector +UT when you go forward a little bit is + + align:start position:0% +UT when you go forward a little bit is + + + align:start position:0% +UT when you go forward a little bit is +actually + + align:start position:0% +actually + + + align:start position:0% +actually +inward un n by an amount uh row Theta + + align:start position:0% +inward un n by an amount uh row Theta + + + align:start position:0% +inward un n by an amount uh row Theta +dot or by an amount Theta dot one times + + align:start position:0% +dot or by an amount Theta dot one times + + + align:start position:0% +dot or by an amount Theta dot one times +Theta dot so we've I'm not going to do + + align:start position:0% +Theta dot so we've I'm not going to do + + + align:start position:0% +Theta dot so we've I'm not going to do +that piece of the derivative before but + + align:start position:0% +that piece of the derivative before but + + + align:start position:0% +that piece of the derivative before but +here is this derivative of the unit + + align:start position:0% +here is this derivative of the unit + + + align:start position:0% +here is this derivative of the unit +Vector it's Theta do unu n so if we + + align:start position:0% +Vector it's Theta do unu n so if we + + + align:start position:0% +Vector it's Theta do unu n so if we +substitute those back in here we can get + + align:start position:0% +substitute those back in here we can get + + + align:start position:0% +substitute those back in here we can get +an expression for our acceleration + + align:start position:0% + + + + align:start position:0% + +this is just the acceleration along the + + align:start position:0% +this is just the acceleration along the + + + align:start position:0% +this is just the acceleration along the +path + + align:start position:0% +path + + + align:start position:0% +path +plus v Theta dot u + + align:start position:0% +plus v Theta dot u + + + align:start position:0% +plus v Theta dot u +n and then we need to take into account + + align:start position:0% +n and then we need to take into account + + + align:start position:0% +n and then we need to take into account +the fact that we know that + + align:start position:0% +the fact that we know that + + + align:start position:0% +the fact that we know that +V the magnitude of the Velocity the + + align:start position:0% +V the magnitude of the Velocity the + + + align:start position:0% +V the magnitude of the Velocity the +speed in other words is row Theta + + align:start position:0% +speed in other words is row Theta + + + align:start position:0% +speed in other words is row Theta +Dot and that means Theta Dot + + align:start position:0% + + + + align:start position:0% + +is V over + + align:start position:0% +is V over + + + align:start position:0% +is V over +row so if we plug that in up here then + + align:start position:0% +row so if we plug that in up here then + + + align:start position:0% +row so if we plug that in up here then +we get an A final expression for our + + align:start position:0% +we get an A final expression for our + + + align:start position:0% +we get an A final expression for our +acceleration V do + + align:start position:0% +acceleration V do + + + align:start position:0% +acceleration V do +UT + + align:start position:0% +UT + + + align:start position:0% +UT +plus v^2 over row u + + align:start position:0% +plus v^2 over row u + + + align:start position:0% +plus v^2 over row u +n and that v^2 over row this is a this + + align:start position:0% +n and that v^2 over row this is a this + + + align:start position:0% +n and that v^2 over row this is a this +is a + + align:start position:0% +is a + + + align:start position:0% +is a +centripetal acceleration term you're + + align:start position:0% +centripetal acceleration term you're + + + align:start position:0% +centripetal acceleration term you're +going around a curve there's an + + align:start position:0% +going around a curve there's an + + + align:start position:0% +going around a curve there's an +acceleration inward it's just like as we + + align:start position:0% +acceleration inward it's just like as we + + + align:start position:0% +acceleration inward it's just like as we +did from Polar coordinates from it comes + + align:start position:0% +did from Polar coordinates from it comes + + + align:start position:0% +did from Polar coordinates from it comes +from rotating things well as soon as you + + align:start position:0% +from rotating things well as soon as you + + + align:start position:0% +from rotating things well as soon as you +go around a curve you're going to + + align:start position:0% +go around a curve you're going to + + + align:start position:0% +go around a curve you're going to +generate an acceleration that is of the + + align:start position:0% +generate an acceleration that is of the + + + align:start position:0% +generate an acceleration that is of the +same kind but now we because you tend to + + align:start position:0% +same kind but now we because you tend to + + + align:start position:0% +same kind but now we because you tend to +know + + align:start position:0% +know + + + align:start position:0% +know +speed it's easier to express it this way + + align:start position:0% +speed it's easier to express it this way + + + align:start position:0% +speed it's easier to express it this way +when you're doing these tangent normal + + align:start position:0% +when you're doing these tangent normal + + + align:start position:0% +when you're doing these tangent normal +problems and this is just the + + align:start position:0% +problems and this is just the + + + align:start position:0% +problems and this is just the +acceleration along the path the usual + + align:start position:0% +acceleration along the path the usual + + + align:start position:0% +acceleration along the path the usual +hit the gas pedal and speed up that's + + align:start position:0% +hit the gas pedal and speed up that's + + + align:start position:0% +hit the gas pedal and speed up that's +this term + + align:start position:0% +this term + + + align:start position:0% +this term +okay so the the piece that I didn't have + + align:start position:0% +okay so the the piece that I didn't have + + + align:start position:0% +okay so the the piece that I didn't have +time to put + + align:start position:0% + + + + align:start position:0% + +up last time which is in the book as is + + align:start position:0% +up last time which is in the book as is + + + align:start position:0% +up last time which is in the book as is +this little derivative the derivation of + + align:start position:0% +this little derivative the derivation of + + + align:start position:0% +this little derivative the derivation of +that is one page in the one of the early + + align:start position:0% +that is one page in the one of the early + + + align:start position:0% +that is one page in the one of the early +chapters of the book how do you get + + align:start position:0% +chapters of the book how do you get + + + align:start position:0% +chapters of the book how do you get +row and row when you have y as a + + align:start position:0% +row and row when you have y as a + + + align:start position:0% +row and row when you have y as a +function of X there's just this formula + + align:start position:0% +function of X there's just this formula + + + align:start position:0% +function of X there's just this formula +from mathematics from calculus that says + + align:start position:0% +from mathematics from calculus that says + + + align:start position:0% +from mathematics from calculus that says +row is dy + + align:start position:0% +row is dy + + + align:start position:0% +row is dy +DX 1 + dydx 2ar to the 3es + + align:start position:0% +DX 1 + dydx 2ar to the 3es + + + align:start position:0% +DX 1 + dydx 2ar to the 3es +power all over the magnitude of + + align:start position:0% +power all over the magnitude of + + + align:start position:0% +power all over the magnitude of +d2y + + align:start position:0% + + + + align:start position:0% + +dx2 and you just calculate these + + align:start position:0% +dx2 and you just calculate these + + + align:start position:0% +dx2 and you just calculate these +quantities and plug them in so + + align:start position:0% +quantities and plug them in so + + + align:start position:0% +quantities and plug them in so +for y = a sin KX X then + + align:start position:0% + + + + align:start position:0% + +dydx is a + + align:start position:0% +dydx is a + + + align:start position:0% +dydx is a +k cosine + + align:start position:0% +k cosine + + + align:start position:0% +k cosine +KX and + + align:start position:0% +KX and + + + align:start position:0% +KX and +D2 Y dx^ + + align:start position:0% +D2 Y dx^ + + + align:start position:0% +D2 Y dx^ +2 is minus a k + + align:start position:0% +2 is minus a k + + + align:start position:0% +2 is minus a k +2 sin + + align:start position:0% +2 sin + + + align:start position:0% +2 sin +KX so we now have these two quantities + + align:start position:0% +KX so we now have these two quantities + + + align:start position:0% +KX so we now have these two quantities +we pick a value of x at which we want to + + align:start position:0% +we pick a value of x at which we want to + + + align:start position:0% +we pick a value of x at which we want to +know the answer like + + align:start position:0% +know the answer like + + + align:start position:0% +know the answer like +0.1 so at 0.1 KX is pi over two right + + align:start position:0% +0.1 so at 0.1 KX is pi over two right + + + align:start position:0% +0.1 so at 0.1 KX is pi over two right +because s's a + + align:start position:0% + + + + align:start position:0% + +maximum X is Lambda over + + align:start position:0% +maximum X is Lambda over + + + align:start position:0% +maximum X is Lambda over +4 KX is Pi / + + align:start position:0% + + + + align:start position:0% + +2 sin KX is 1 + + align:start position:0% +2 sin KX is 1 + + + align:start position:0% +2 sin KX is 1 +cosine + + align:start position:0% +cosine + + + align:start position:0% +cosine +KX zero and so we can calculate + + align:start position:0% + + + + align:start position:0% + +row + + align:start position:0% +row + + + align:start position:0% +row +1+ + + align:start position:0% +1+ + + + align:start position:0% +1+ +and dydx the derivative is cosine that's + + align:start position:0% +and dydx the derivative is cosine that's + + + align:start position:0% +and dydx the derivative is cosine that's +zero so this term in + + align:start position:0% + + + + align:start position:0% + +here is zero this is to the three halves + + align:start position:0% +here is zero this is to the three halves + + + align:start position:0% +here is zero this is to the three halves +that's pretty easy to calculate this + + align:start position:0% +that's pretty easy to calculate this + + + align:start position:0% +that's pretty easy to calculate this +term down here D2 Y dx^ 2 well s of KX + + align:start position:0% +term down here D2 Y dx^ 2 well s of KX + + + align:start position:0% +term down here D2 Y dx^ 2 well s of KX +is 1 so that's uh minus a^ 2 but this is + + align:start position:0% +is 1 so that's uh minus a^ 2 but this is + + + align:start position:0% +is 1 so that's uh minus a^ 2 but this is +an absolute value + + align:start position:0% + + + + align:start position:0% + +sign so this just turns out to be one + + align:start position:0% +sign so this just turns out to be one + + + align:start position:0% +sign so this just turns out to be one +over a k + + align:start position:0% +over a k + + + align:start position:0% +over a k +2 and we plug in some + + align:start position:0% +2 and we plug in some + + + align:start position:0% +2 and we plug in some +numbers I'm going to let + + align:start position:0% +numbers I'm going to let + + + align:start position:0% +numbers I'm going to let +uh my Lambda be 150 m + + align:start position:0% +uh my Lambda be 150 m + + + align:start position:0% +uh my Lambda be 150 m +M my amplitude here that I'm swerving + + align:start position:0% +M my amplitude here that I'm swerving + + + align:start position:0% +M my amplitude here that I'm swerving +back and forth let's make that 5 + + align:start position:0% + + + + align:start position:0% + +m uh we need + + align:start position:0% +m uh we need + + + align:start position:0% +m uh we need +a that's all we need to get row so Row + + align:start position:0% +a that's all we need to get row so Row + + + align:start position:0% +a that's all we need to get row so Row +in this case works out to be + + align:start position:0% +in this case works out to be + + + align:start position:0% +in this case works out to be +114 m so the radius of curvature of this + + align:start position:0% +114 m so the radius of curvature of this + + + align:start position:0% +114 m so the radius of curvature of this +road that I'm driving down at that that + + align:start position:0% +road that I'm driving down at that that + + + align:start position:0% +road that I'm driving down at that that +point right at the peak in the curve is + + align:start position:0% +point right at the peak in the curve is + + + align:start position:0% +point right at the peak in the curve is +114 m + + align:start position:0% + + + + align:start position:0% + +so the + + align:start position:0% +so the + + + align:start position:0% +so the +acceleration that I'm looking for a well + + align:start position:0% +acceleration that I'm looking for a well + + + align:start position:0% +acceleration that I'm looking for a well +it's V + + align:start position:0% +it's V + + + align:start position:0% +it's V +Dot UT and if I'm not accelera I'm not + + align:start position:0% +Dot UT and if I'm not accelera I'm not + + + align:start position:0% +Dot UT and if I'm not accelera I'm not +hitting the gas pedal constant speed + + align:start position:0% +hitting the gas pedal constant speed + + + align:start position:0% +hitting the gas pedal constant speed +I'll let that one be + + align:start position:0% +I'll let that one be + + + align:start position:0% +I'll let that one be +zero and the other one then is v^2 over + + align:start position:0% +zero and the other one then is v^2 over + + + align:start position:0% +zero and the other one then is v^2 over +row in the unu direction and let's let + + align:start position:0% +row in the unu direction and let's let + + + align:start position:0% +row in the unu direction and let's let +V equal + + align:start position:0% +V equal + + + align:start position:0% +V equal +um I have here in my example 20 meters + + align:start position:0% +um I have here in my example 20 meters + + + align:start position:0% +um I have here in my example 20 meters +per + + align:start position:0% +per + + + align:start position:0% +per +second which is about 40 knots and a + + align:start position:0% +second which is about 40 knots and a + + + align:start position:0% +second which is about 40 knots and a +knot is 15% more than a mile per hour so + + align:start position:0% +knot is 15% more than a mile per hour so + + + align:start position:0% +knot is 15% more than a mile per hour so +it's somewhere about 45 miles an hour so + + align:start position:0% +it's somewhere about 45 miles an hour so + + + align:start position:0% +it's somewhere about 45 miles an hour so +a typical Road speed driving down the + + align:start position:0% +a typical Road speed driving down the + + + align:start position:0% +a typical Road speed driving down the +road 20 m/ second now you can plug in + + align:start position:0% +road 20 m/ second now you can plug in + + + align:start position:0% +road 20 m/ second now you can plug in +here you can plug in here and you can + + align:start position:0% +here you can plug in here and you can + + + align:start position:0% +here you can plug in here and you can +find that the + + align:start position:0% +find that the + + + align:start position:0% +find that the +acceleration I work out here is + + align:start position:0% + + + + align:start position:0% + +3.51 m/s squar + + align:start position:0% +3.51 m/s squar + + + align:start position:0% +3.51 m/s squar +and in what direction is + + align:start position:0% + + + + align:start position:0% + +it what direction is that + + align:start position:0% + + + + align:start position:0% + +acceleration the normal it's in the + + align:start position:0% +acceleration the normal it's in the + + + align:start position:0% +acceleration the normal it's in the +normal direction is it to the inside of + + align:start position:0% +normal direction is it to the inside of + + + align:start position:0% +normal direction is it to the inside of +the curve or the outside of the curve + + align:start position:0% +the curve or the outside of the curve + + + align:start position:0% +the curve or the outside of the curve +inside always to the inside of the curve + + align:start position:0% +inside always to the inside of the curve + + + align:start position:0% +inside always to the inside of the curve +so these tangent this tangent normal + + align:start position:0% +so these tangent this tangent normal + + + align:start position:0% +so these tangent this tangent normal +coordinates are really simple + + align:start position:0% +coordinates are really simple + + + align:start position:0% +coordinates are really simple +coordinates they're they're meant for a + + align:start position:0% +coordinates they're they're meant for a + + + align:start position:0% +coordinates they're they're meant for a +particular kind of simple problem when + + align:start position:0% +particular kind of simple problem when + + + align:start position:0% +particular kind of simple problem when +you know the + + align:start position:0% +you know the + + + align:start position:0% +you know the +path and it's just defined the normal + + align:start position:0% +path and it's just defined the normal + + + align:start position:0% +path and it's just defined the normal +unu is positive always inward to the + + align:start position:0% +unu is positive always inward to the + + + align:start position:0% +unu is positive always inward to the +center of the curve pointing toward + + align:start position:0% +center of the curve pointing toward + + + align:start position:0% +center of the curve pointing toward +where the center of rotation where that + + align:start position:0% +where the center of rotation where that + + + align:start position:0% +where the center of rotation where that +radius of where your radius of curve is + + align:start position:0% +radius of where your radius of curve is + + + align:start position:0% +radius of where your radius of curve is +always pointing at the origin of that + + align:start position:0% +always pointing at the origin of that + + + align:start position:0% +always pointing at the origin of that +radius of your curve okay so G is order + + align:start position:0% +radius of your curve okay so G is order + + + align:start position:0% +radius of your curve okay so G is order +of 10 m/s squared so that's about a + + align:start position:0% +of 10 m/s squared so that's about a + + + align:start position:0% +of 10 m/s squared so that's about a +third of a g would + + align:start position:0% +third of a g would + + + align:start position:0% +third of a g would +you third of a g enough to notice + + align:start position:0% + + + + align:start position:0% + +yeah absolutely you get you get pushed + + align:start position:0% +yeah absolutely you get you get pushed + + + align:start position:0% +yeah absolutely you get you get pushed +to the side of the car if you do that + + align:start position:0% +to the side of the car if you do that + + + align:start position:0% +to the side of the car if you do that +okay all + + align:start position:0% +okay all + + + align:start position:0% +okay all +right so let's we'll any questions about + + align:start position:0% +right so let's we'll any questions about + + + align:start position:0% +right so let's we'll any questions about +that I'm going to move on next if not + + align:start position:0% +that I'm going to move on next if not + + + align:start position:0% +that I'm going to move on next if not +I'm going to move on to linear impulse + + align:start position:0% +I'm going to move on to linear impulse + + + align:start position:0% +I'm going to move on to linear impulse +and + + align:start position:0% + + + + align:start position:0% + +momentum and this will be a quick review + + align:start position:0% +momentum and this will be a quick review + + + align:start position:0% +momentum and this will be a quick review +because + + align:start position:0% + + + + align:start position:0% + +this is is consists of the physics the + + align:start position:0% +this is is consists of the physics the + + + align:start position:0% +this is is consists of the physics the +kind of physics that you've done lots of + + align:start position:0% +kind of physics that you've done lots of + + + align:start position:0% +kind of physics that you've done lots of +times so I'm going to hit it quickly and + + align:start position:0% +times so I'm going to hit it quickly and + + + align:start position:0% +times so I'm going to hit it quickly and +then move on to angular + + align:start position:0% + + + + align:start position:0% + +momentum so we know for a particle this + + align:start position:0% +momentum so we know for a particle this + + + align:start position:0% +momentum so we know for a particle this +is what Newton told us you've got a + + align:start position:0% +is what Newton told us you've got a + + + align:start position:0% +is what Newton told us you've got a +particle here that's some mass m we know + + align:start position:0% +particle here that's some mass m we know + + + align:start position:0% +particle here that's some mass m we know +for a part it has some external forces + + align:start position:0% +for a part it has some external forces + + + align:start position:0% +for a part it has some external forces +on + + align:start position:0% + + + + align:start position:0% + +it we know for a particle that the sum + + align:start position:0% +it we know for a particle that the sum + + + align:start position:0% +it we know for a particle that the sum +of these external forces a vector + + align:start position:0% +of these external forces a vector + + + align:start position:0% +of these external forces a vector +sum is equal to the mass times the + + align:start position:0% +sum is equal to the mass times the + + + align:start position:0% +sum is equal to the mass times the +acceleration for the particle Newton + + align:start position:0% +acceleration for the particle Newton + + + align:start position:0% +acceleration for the particle Newton +Second + + align:start position:0% + + + + align:start position:0% + +Law and that's the mass times the + + align:start position:0% +Law and that's the mass times the + + + align:start position:0% +Law and that's the mass times the +derivative of the Velocity with respect + + align:start position:0% +derivative of the Velocity with respect + + + align:start position:0% +derivative of the Velocity with respect +to time that's where we get + + align:start position:0% +to time that's where we get + + + align:start position:0% +to time that's where we get +acceleration so this formula we can just + + align:start position:0% +acceleration so this formula we can just + + + align:start position:0% +acceleration so this formula we can just +rearrange the DTs a little bit so the + + align:start position:0% +rearrange the DTs a little bit so the + + + align:start position:0% +rearrange the DTs a little bit so the +summation of the forces + + align:start position:0% + + + + align:start position:0% + +DT is M DV and I want to integrate + + align:start position:0% +DT is M DV and I want to integrate + + + align:start position:0% +DT is M DV and I want to integrate +these so if I integrate this over time + + align:start position:0% +these so if I integrate this over time + + + align:start position:0% +these so if I integrate this over time +from some T1 to T2 this equality says + + align:start position:0% +from some T1 to T2 this equality says + + + align:start position:0% +from some T1 to T2 this equality says +we're going to find some change in + + align:start position:0% +we're going to find some change in + + + align:start position:0% +we're going to find some change in +velocity from V1 to + + align:start position:0% +velocity from V1 to + + + align:start position:0% +velocity from V1 to +V2 and this is our this is kind of the + + align:start position:0% +V2 and this is our this is kind of the + + + align:start position:0% +V2 and this is our this is kind of the +beginning of our impulse momentum + + align:start position:0% +beginning of our impulse momentum + + + align:start position:0% +beginning of our impulse momentum +relationship we tend to call the + + align:start position:0% +relationship we tend to call the + + + align:start position:0% +relationship we tend to call the +integration of forces over time + + align:start position:0% +integration of forces over time + + + align:start position:0% +integration of forces over time +impulse and if you have a nonzero + + align:start position:0% +impulse and if you have a nonzero + + + align:start position:0% +impulse and if you have a nonzero +impulse that leads to a change in the + + align:start position:0% +impulse that leads to a change in the + + + align:start position:0% +impulse that leads to a change in the +linear momentum + + align:start position:0% +linear momentum + + + align:start position:0% +linear momentum +okay so when you carry out + + align:start position:0% +okay so when you carry out + + + align:start position:0% +okay so when you carry out +so so they're writing this a little bit + + align:start position:0% +so so they're writing this a little bit + + + align:start position:0% +so so they're writing this a little bit +different way you can do summation + + align:start position:0% +different way you can do summation + + + align:start position:0% +different way you can do summation +because these are vectors and we have + + align:start position:0% +because these are vectors and we have + + + align:start position:0% +because these are vectors and we have +rules about vectors you can bring the + + align:start position:0% +rules about vectors you can bring the + + + align:start position:0% +rules about vectors you can bring the +summation outside of the integral + + align:start position:0% +summation outside of the integral + + + align:start position:0% +summation outside of the integral +so that this says the + + align:start position:0% +so that this says the + + + align:start position:0% +so that this says the +summation of the integral from T1 to T2 + + align:start position:0% +summation of the integral from T1 to T2 + + + align:start position:0% +summation of the integral from T1 to T2 +of these external + + align:start position:0% + + + + align:start position:0% + +forces is just + + align:start position:0% +forces is just + + + align:start position:0% +forces is just +m V2 minus mv1 because the integral on + + align:start position:0% +m V2 minus mv1 because the integral on + + + align:start position:0% +m V2 minus mv1 because the integral on +the right hand side + + align:start position:0% +the right hand side + + + align:start position:0% +the right hand side +is really + + align:start position:0% +is really + + + align:start position:0% +is really +simple and we'll finally State this in a + + align:start position:0% +simple and we'll finally State this in a + + + align:start position:0% +simple and we'll finally State this in a +uh way that we most commonly use it + + align:start position:0% +uh way that we most commonly use it + + + align:start position:0% +uh way that we most commonly use it +moving this term to the left so you + + align:start position:0% +moving this term to the left so you + + + align:start position:0% +moving this term to the left so you +start off with an initial momentum + + align:start position:0% +start off with an initial momentum + + + align:start position:0% +start off with an initial momentum +mv1 you add to + + align:start position:0% +mv1 you add to + + + align:start position:0% +mv1 you add to +it the summation of the impulses that + + align:start position:0% +it the summation of the impulses that + + + align:start position:0% +it the summation of the impulses that +you that occur over + + align:start position:0% +you that occur over + + + align:start position:0% +you that occur over +time T1 to T2 of the external + + align:start position:0% +time T1 to T2 of the external + + + align:start position:0% +time T1 to T2 of the external +forces and you get the final momentum + + align:start position:0% +forces and you get the final momentum + + + align:start position:0% +forces and you get the final momentum +mv2 and this is the way you usually use + + align:start position:0% +mv2 and this is the way you usually use + + + align:start position:0% +mv2 and this is the way you usually use +the formula so what happens if there's + + align:start position:0% +the formula so what happens if there's + + + align:start position:0% +the formula so what happens if there's +no external + + align:start position:0% + + + + align:start position:0% + +forces that's that's where we get the + + align:start position:0% +forces that's that's where we get the + + + align:start position:0% +forces that's that's where we get the +law of conservation of momentum if there + + align:start position:0% +law of conservation of momentum if there + + + align:start position:0% +law of conservation of momentum if there +are no external forces on the particle + + align:start position:0% +are no external forces on the particle + + + align:start position:0% +are no external forces on the particle +the momentum doesn't change and mv1 is + + align:start position:0% +the momentum doesn't change and mv1 is + + + align:start position:0% +the momentum doesn't change and mv1 is +got to be equal to + + align:start position:0% + + + + align:start position:0% + +mv2 whoops + + align:start position:0% + + + + align:start position:0% + +so just a a really trivial + + align:start position:0% +so just a a really trivial + + + align:start position:0% +so just a a really trivial +example drawing for something that we've + + align:start position:0% +example drawing for something that we've + + + align:start position:0% +example drawing for something that we've +done before you get the block sliding + + align:start position:0% +done before you get the block sliding + + + align:start position:0% +done before you get the block sliding +down the + + align:start position:0% +down the + + + align:start position:0% +down the +hill draw your free body + + align:start position:0% +hill draw your free body + + + align:start position:0% +hill draw your free body +diagram got + + align:start position:0% +diagram got + + + align:start position:0% +diagram got +friction got + + align:start position:0% +friction got + + + align:start position:0% +friction got +gravity got a normal + + align:start position:0% + + + + align:start position:0% + +force and we'll set ourselves up with a + + align:start position:0% +force and we'll set ourselves up with a + + + align:start position:0% +force and we'll set ourselves up with a +coordinat system aligned with the motion + + align:start position:0% +coordinat system aligned with the motion + + + align:start position:0% +coordinat system aligned with the motion +we're interested in so this is an + + align:start position:0% +we're interested in so this is an + + + align:start position:0% +we're interested in so this is an +inertial + + align:start position:0% +inertial + + + align:start position:0% +inertial +system + + align:start position:0% + + + + align:start position:0% + +XY and we've done this problem before so + + align:start position:0% +XY and we've done this problem before so + + + align:start position:0% +XY and we've done this problem before so +we said the summation we found out that + + align:start position:0% +we said the summation we found out that + + + align:start position:0% +we said the summation we found out that +the summation of the + + align:start position:0% +the summation of the + + + align:start position:0% +the summation of the +forces in the X Direction and ah this is + + align:start position:0% +forces in the X Direction and ah this is + + + align:start position:0% +forces in the X Direction and ah this is +a good moment to take an aside for a + + align:start position:0% +a good moment to take an aside for a + + + align:start position:0% +a good moment to take an aside for a +second this was a + + align:start position:0% +second this was a + + + align:start position:0% +second this was a +vector expression but you can break it + + align:start position:0% +vector expression but you can break it + + + align:start position:0% +vector expression but you can break it +you can implement it you can break it + + align:start position:0% +you can implement it you can break it + + + align:start position:0% +you can implement it you can break it +down into its individ idual Vector + + align:start position:0% +down into its individ idual Vector + + + align:start position:0% +down into its individ idual Vector +components so that equation gives you + + align:start position:0% +components so that equation gives you + + + align:start position:0% +components so that equation gives you +for particles gives you + + align:start position:0% +for particles gives you + + + align:start position:0% +for particles gives you +three sub equations one in the X one in + + align:start position:0% +three sub equations one in the X one in + + + align:start position:0% +three sub equations one in the X one in +the Y one in the Z and you can use them + + align:start position:0% +the Y one in the Z and you can use them + + + align:start position:0% +the Y one in the Z and you can use them +each independently so in this case we're + + align:start position:0% +each independently so in this case we're + + + align:start position:0% +each independently so in this case we're +going to use the only need the X + + align:start position:0% +going to use the only need the X + + + align:start position:0% +going to use the only need the X +component in order to do the problem so + + align:start position:0% +component in order to do the problem so + + + align:start position:0% +component in order to do the problem so +the sum of the forces in the X Direction + + align:start position:0% +the sum of the forces in the X Direction + + + align:start position:0% +the sum of the forces in the X Direction +now and this problem we've we which we + + align:start position:0% +now and this problem we've we which we + + + align:start position:0% +now and this problem we've we which we +have done + + align:start position:0% +have done + + + align:start position:0% +have done +before + + align:start position:0% +before + + + align:start position:0% +before +is + + align:start position:0% +is + + + align:start position:0% +is +mg sin Theta that component of gravity + + align:start position:0% +mg sin Theta that component of gravity + + + align:start position:0% +mg sin Theta that component of gravity +pulling it down the hip + + align:start position:0% +pulling it down the hip + + + align:start position:0% +pulling it down the hip +minus + + align:start position:0% +minus + + + align:start position:0% +minus +mu mg cosine Theta and that's the + + align:start position:0% +mu mg cosine Theta and that's the + + + align:start position:0% +mu mg cosine Theta and that's the +friction and none of these are functions + + align:start position:0% +friction and none of these are functions + + + align:start position:0% +friction and none of these are functions +of + + align:start position:0% +of + + + align:start position:0% +of +time so that whole thing is just some + + align:start position:0% +time so that whole thing is just some + + + align:start position:0% +time so that whole thing is just some +constant I'll just call it + + align:start position:0% +constant I'll just call it + + + align:start position:0% +constant I'll just call it +K right so the total forces on this + + align:start position:0% +K right so the total forces on this + + + align:start position:0% +K right so the total forces on this +system in the X direction is just some + + align:start position:0% +system in the X direction is just some + + + align:start position:0% +system in the X direction is just some +constant and that makes this integral up + + align:start position:0% +constant and that makes this integral up + + + align:start position:0% +constant and that makes this integral up +here pretty trivial to uh Implement so + + align:start position:0% +here pretty trivial to uh Implement so + + + align:start position:0% +here pretty trivial to uh Implement so +now we can say that m + + align:start position:0% +now we can say that m + + + align:start position:0% +now we can say that m +V1 I'll just make it v1x to emphasize + + align:start position:0% +V1 I'll just make it v1x to emphasize + + + align:start position:0% +V1 I'll just make it v1x to emphasize +that integral from zero or T1 to T2 but + + align:start position:0% +that integral from zero or T1 to T2 but + + + align:start position:0% +that integral from zero or T1 to T2 but +I'm going to let T1 be zero usually + + align:start position:0% +I'm going to let T1 be zero usually + + + align:start position:0% +I'm going to let T1 be zero usually +makes it problems easier so from Zer to + + align:start position:0% +makes it problems easier so from Zer to + + + align:start position:0% +makes it problems easier so from Zer to +t 0 to T of + + align:start position:0% +t 0 to T of + + + align:start position:0% +t 0 to T of +kdt equals + + align:start position:0% +kdt equals + + + align:start position:0% +kdt equals +mv2 I can't write this morning in the X + + align:start position:0% +mv2 I can't write this morning in the X + + + align:start position:0% +mv2 I can't write this morning in the X +Direction and if V1 + + align:start position:0% + + + + align:start position:0% + +X is zero starts off at zero + + align:start position:0% +X is zero starts off at zero + + + align:start position:0% +X is zero starts off at zero +time and zero velocity when you let it + + align:start position:0% +time and zero velocity when you let it + + + align:start position:0% +time and zero velocity when you let it +go to start with then you this then this + + align:start position:0% +go to start with then you this then this + + + align:start position:0% +go to start with then you this then this +term will go away and we can just + + align:start position:0% +term will go away and we can just + + + align:start position:0% +term will go away and we can just +implement this integral and the integral + + align:start position:0% +implement this integral and the integral + + + align:start position:0% +implement this integral and the integral +of kdt + + align:start position:0% +of kdt + + + align:start position:0% +of kdt +is KT right so this says then + + align:start position:0% +is KT right so this says then + + + align:start position:0% +is KT right so this says then +that KT evaluated from zero to + + align:start position:0% +that KT evaluated from zero to + + + align:start position:0% +that KT evaluated from zero to +some time that we want to know the + + align:start position:0% +some time that we want to know the + + + align:start position:0% +some time that we want to know the +answer is m + + align:start position:0% +answer is m + + + align:start position:0% +answer is m +V2 in the X Direction and so let's + + align:start position:0% +V2 in the X Direction and so let's + + + align:start position:0% +V2 in the X Direction and so let's +let T = 3 + + align:start position:0% +let T = 3 + + + align:start position:0% +let T = 3 +seconds you find out that + + align:start position:0% +seconds you find out that + + + align:start position:0% +seconds you find out that +v2x + + align:start position:0% +v2x + + + align:start position:0% +v2x +is + + align:start position:0% +is + + + align:start position:0% +is +3 K Over + + align:start position:0% +3 K Over + + + align:start position:0% +3 K Over +M + + align:start position:0% +M + + + align:start position:0% +M +right and in this problem then that + + align:start position:0% +right and in this problem then that + + + align:start position:0% +right and in this problem then that +looks like 3 G + + align:start position:0% +looks like 3 G + + + align:start position:0% +looks like 3 G +sin Theta + + align:start position:0% +sin Theta + + + align:start position:0% +sin Theta +minus mu cosine Theta so this + + align:start position:0% + + + + align:start position:0% + +really a trivial almost trivial example + + align:start position:0% +really a trivial almost trivial example + + + align:start position:0% +really a trivial almost trivial example +it's not a hard example but it + + align:start position:0% +it's not a hard example but it + + + align:start position:0% +it's not a hard example but it +emphasizes all of the key points in the + + align:start position:0% +emphasizes all of the key points in the + + + align:start position:0% +emphasizes all of the key points in the +problem start off with a vector equation + + align:start position:0% +problem start off with a vector equation + + + align:start position:0% +problem start off with a vector equation +you can apply it in any one of the three + + align:start position:0% +you can apply it in any one of the three + + + align:start position:0% +you can apply it in any one of the three +Vector d three Vector component + + align:start position:0% +Vector d three Vector component + + + align:start position:0% +Vector d three Vector component +directions you integrate the forces the + + align:start position:0% +directions you integrate the forces the + + + align:start position:0% +directions you integrate the forces the +sum of the forces on the object in that + + align:start position:0% +sum of the forces on the object in that + + + align:start position:0% +sum of the forces on the object in that +direction Direction over time and you + + align:start position:0% +direction Direction over time and you + + + align:start position:0% +direction Direction over time and you +apply the impulse momentum formula and + + align:start position:0% +apply the impulse momentum formula and + + + align:start position:0% +apply the impulse momentum formula and +you get the answer you can do that so + + align:start position:0% +you get the answer you can do that so + + + align:start position:0% +you get the answer you can do that so +that basic step-by-step process is how + + align:start position:0% +that basic step-by-step process is how + + + align:start position:0% +that basic step-by-step process is how +you basically most impulse momentum + + align:start position:0% +you basically most impulse momentum + + + align:start position:0% +you basically most impulse momentum +problems are done and if there's no + + align:start position:0% +problems are done and if there's no + + + align:start position:0% +problems are done and if there's no +forces then you have conservation of + + align:start position:0% + + + + align:start position:0% + +momentum okay so let's do uh there's + + align:start position:0% +momentum okay so let's do uh there's + + + align:start position:0% +momentum okay so let's do uh there's +this was for particle + + align:start position:0% + + + + align:start position:0% + +just a + + align:start position:0% +just a + + + align:start position:0% +just a +quick reminder of we need to ask + + align:start position:0% +quick reminder of we need to ask + + + align:start position:0% +quick reminder of we need to ask +ourselves does this apply to groups of + + align:start position:0% +ourselves does this apply to groups of + + + align:start position:0% +ourselves does this apply to groups of +particles systems of particles well + + align:start position:0% +particles systems of particles well + + + align:start position:0% +particles systems of particles well +remember that we said if you've got a + + align:start position:0% +remember that we said if you've got a + + + align:start position:0% +remember that we said if you've got a +bunch of + + align:start position:0% +bunch of + + + align:start position:0% +bunch of +particles a + + align:start position:0% +particles a + + + align:start position:0% +particles a +system all of these are the M + + align:start position:0% +system all of these are the M + + + align:start position:0% +system all of these are the M +eyes we've already figured out that the + + align:start position:0% +eyes we've already figured out that the + + + align:start position:0% +eyes we've already figured out that the +total mass of the system times the + + align:start position:0% +total mass of the system times the + + + align:start position:0% +total mass of the system times the +velocity of the center of mass this is G + + align:start position:0% +velocity of the center of mass this is G + + + align:start position:0% +velocity of the center of mass this is G +is my center of + + align:start position:0% +is my center of + + + align:start position:0% +is my center of +mass with respect to + + align:start position:0% +mass with respect to + + + align:start position:0% +mass with respect to +my inertial + + align:start position:0% +my inertial + + + align:start position:0% +my inertial +frame so this is the momentum of the + + align:start position:0% +frame so this is the momentum of the + + + align:start position:0% +frame so this is the momentum of the +system that was just the summation of + + align:start position:0% +system that was just the summation of + + + align:start position:0% +system that was just the summation of +the individual Mi VI I with respect to + + align:start position:0% + + + + align:start position:0% + +O and further more we took the + + align:start position:0% +O and further more we took the + + + align:start position:0% +O and further more we took the +derivative of this so this is the + + align:start position:0% +derivative of this so this is the + + + align:start position:0% +derivative of this so this is the +momentum of the system the time + + align:start position:0% +momentum of the system the time + + + align:start position:0% +momentum of the system the time +derivative of the momentum should be the + + align:start position:0% +derivative of the momentum should be the + + + align:start position:0% +derivative of the momentum should be the +external forces so that we were able to + + align:start position:0% +external forces so that we were able to + + + align:start position:0% +external forces so that we were able to +by taking that derivative you get Mt the + + align:start position:0% +by taking that derivative you get Mt the + + + align:start position:0% +by taking that derivative you get Mt the +total masstimes v g with respect to O + + align:start position:0% +total masstimes v g with respect to O + + + align:start position:0% +total masstimes v g with respect to O +DOT and that + + align:start position:0% +DOT and that + + + align:start position:0% +DOT and that +had better give you be equal to the + + align:start position:0% +had better give you be equal to the + + + align:start position:0% +had better give you be equal to the +summation of the + + align:start position:0% +summation of the + + + align:start position:0% +summation of the +external forces + + align:start position:0% +external forces + + + align:start position:0% +external forces +on all the particles because you can do + + align:start position:0% +on all the particles because you can do + + + align:start position:0% +on all the particles because you can do +it one particle at a time and they all + + align:start position:0% +it one particle at a time and they all + + + align:start position:0% +it one particle at a time and they all +add each each of these particles has + + align:start position:0% +add each each of these particles has + + + align:start position:0% +add each each of these particles has +forces you sum them all up you get these + + align:start position:0% +forces you sum them all up you get these + + + align:start position:0% +forces you sum them all up you get these +forces + + align:start position:0% +forces + + + align:start position:0% +forces +and this is this allows you to say that + + align:start position:0% +and this is this allows you to say that + + + align:start position:0% +and this is this allows you to say that +the sum of all of the external forces on + + align:start position:0% +the sum of all of the external forces on + + + align:start position:0% +the sum of all of the external forces on +the system is equal to the total mass of + + align:start position:0% +the system is equal to the total mass of + + + align:start position:0% +the system is equal to the total mass of +the system times the acceleration of the + + align:start position:0% +the system times the acceleration of the + + + align:start position:0% +the system times the acceleration of the +center of + + align:start position:0% +center of + + + align:start position:0% +center of +mass so this formula now can it looks + + align:start position:0% +mass so this formula now can it looks + + + align:start position:0% +mass so this formula now can it looks +very similar to where we started with + + align:start position:0% +very similar to where we started with + + + align:start position:0% +very similar to where we started with +this little derivation for a particle + + align:start position:0% +this little derivation for a particle + + + align:start position:0% +this little derivation for a particle +you can now say that the summation this + + align:start position:0% +you can now say that the summation this + + + align:start position:0% +you can now say that the summation this +all leads to the + + align:start position:0% +all leads to the + + + align:start position:0% +all leads to the +summation of the integral from T1 to + + align:start position:0% +summation of the integral from T1 to + + + align:start position:0% +summation of the integral from T1 to +T2 of all of + + align:start position:0% +T2 of all of + + + align:start position:0% +T2 of all of +these forces over + + align:start position:0% + + + + align:start position:0% + +time gives you the + + align:start position:0% +time gives you the + + + align:start position:0% +time gives you the +change in the total linear momentum of + + align:start position:0% +change in the total linear momentum of + + + align:start position:0% +change in the total linear momentum of +the system system v g with respect to + + align:start position:0% + + + + align:start position:0% + +o1 two rather minus VG with respect to + + align:start position:0% +o1 two rather minus VG with respect to + + + align:start position:0% +o1 two rather minus VG with respect to +o 2 the second one so this is exactly + + align:start position:0% +o 2 the second one so this is exactly + + + align:start position:0% +o 2 the second one so this is exactly +the same kind of formulation the change + + align:start position:0% +the same kind of formulation the change + + + align:start position:0% +the same kind of formulation the change +in the linear momentum of the + + align:start position:0% +in the linear momentum of the + + + align:start position:0% +in the linear momentum of the +system is equal to the integral of the + + align:start position:0% +system is equal to the integral of the + + + align:start position:0% +system is equal to the integral of the +forces on the system over time so the + + align:start position:0% +forces on the system over time so the + + + align:start position:0% +forces on the system over time so the +impulse to the system so it all this + + align:start position:0% +impulse to the system so it all this + + + align:start position:0% +impulse to the system so it all this +allows you to do problems that you might + + align:start position:0% +allows you to do problems that you might + + + align:start position:0% +allows you to do problems that you might +not + + align:start position:0% +not + + + align:start position:0% +not +have thought about before so I've think + + align:start position:0% +have thought about before so I've think + + + align:start position:0% +have thought about before so I've think +about uh something like this I've got an + + align:start position:0% + + + + align:start position:0% + +old uh back re you know Revolutionary + + align:start position:0% +old uh back re you know Revolutionary + + + align:start position:0% +old uh back re you know Revolutionary +War earlier period + + align:start position:0% + + + + align:start position:0% + +Canon I can't I'm trying to + + align:start position:0% +Canon I can't I'm trying to + + + align:start position:0% +Canon I can't I'm trying to +draw so here's my Cannon barrel and back + + align:start position:0% +draw so here's my Cannon barrel and back + + + align:start position:0% +draw so here's my Cannon barrel and back +in those days + + align:start position:0% + + + + align:start position:0% + +draw a little better job here so we got + + align:start position:0% +draw a little better job here so we got + + + align:start position:0% +draw a little better job here so we got +this cannon sitting here and in the + + align:start position:0% +this cannon sitting here and in the + + + align:start position:0% +this cannon sitting here and in the +barrel you've got a bunch of what's + + align:start position:0% +barrel you've got a bunch of what's + + + align:start position:0% +barrel you've got a bunch of what's +known as in the old days known as grape + + align:start position:0% +known as in the old days known as grape + + + align:start position:0% +known as in the old days known as grape +shot so sometimes for kind for anti + + align:start position:0% +shot so sometimes for kind for anti + + + align:start position:0% +shot so sometimes for kind for anti +Personnel kind of stuff they would just + + align:start position:0% +Personnel kind of stuff they would just + + + align:start position:0% +Personnel kind of stuff they would just +throw a whole bunch of metal and junk + + align:start position:0% +throw a whole bunch of metal and junk + + + align:start position:0% +throw a whole bunch of metal and junk +into it but just imagine a bunch of iron + + align:start position:0% +into it but just imagine a bunch of iron + + + align:start position:0% +into it but just imagine a bunch of iron +balls or lead balls or rocks or whatever + + align:start position:0% +balls or lead balls or rocks or whatever + + + align:start position:0% +balls or lead balls or rocks or whatever +you want to put in there and you put a + + align:start position:0% +you want to put in there and you put a + + + align:start position:0% +you want to put in there and you put a +whole mess of them in here and you have + + align:start position:0% +whole mess of them in here and you have + + + align:start position:0% +whole mess of them in here and you have +a charge + + align:start position:0% +a charge + + + align:start position:0% +a charge +you set it off and it shoots them out + + align:start position:0% +you set it off and it shoots them out + + + align:start position:0% +you set it off and it shoots them out +the end of the gun I want to know what's + + align:start position:0% +the end of the gun I want to know what's + + + align:start position:0% +the end of the gun I want to know what's +the + + align:start position:0% + + + + align:start position:0% + +reaction what's the reaction force on + + align:start position:0% +reaction what's the reaction force on + + + align:start position:0% +reaction what's the reaction force on +the + + align:start position:0% +the + + + align:start position:0% +the +gun now how much what's when that gun + + align:start position:0% +gun now how much what's when that gun + + + align:start position:0% +gun now how much what's when that gun +when that charge goes off if you ever if + + align:start position:0% +when that charge goes off if you ever if + + + align:start position:0% +when that charge goes off if you ever if +you go down to the Constitution which is + + align:start position:0% +you go down to the Constitution which is + + + align:start position:0% +you go down to the Constitution which is +the + + align:start position:0% +the + + + align:start position:0% +the +oldest commissioned warship in the US + + align:start position:0% +oldest commissioned warship in the US + + + align:start position:0% +oldest commissioned warship in the US +Navy still afloat it's that I don't know + + align:start position:0% +Navy still afloat it's that I don't know + + + align:start position:0% +Navy still afloat it's that I don't know +if any of you have seen it down here in + + align:start position:0% +if any of you have seen it down here in + + + align:start position:0% +if any of you have seen it down here in +the dock in Chelsea was built around + + align:start position:0% +the dock in Chelsea was built around + + + align:start position:0% +the dock in Chelsea was built around +1799 but when one of those when they + + align:start position:0% +1799 but when one of those when they + + + align:start position:0% +1799 but when one of those when they +shot one of those guns the gun would + + align:start position:0% +shot one of those guns the gun would + + + align:start position:0% +shot one of those guns the gun would +roll back several feet and get dragged + + align:start position:0% +roll back several feet and get dragged + + + align:start position:0% +roll back several feet and get dragged +to a stop by a bunch of restraining + + align:start position:0% +to a stop by a bunch of restraining + + + align:start position:0% +to a stop by a bunch of restraining +lines and then dragged back up for + + align:start position:0% +lines and then dragged back up for + + + align:start position:0% +lines and then dragged back up for +another for another load so the reaction + + align:start position:0% +another for another load so the reaction + + + align:start position:0% +another for another load so the reaction +force the force pushing back these + + align:start position:0% +force the force pushing back these + + + align:start position:0% +force the force pushing back these +things are used to sitting on + + align:start position:0% +things are used to sitting on + + + align:start position:0% +things are used to sitting on +Wheels could be pretty large let let's + + align:start position:0% +Wheels could be pretty large let let's + + + align:start position:0% +Wheels could be pretty large let let's +take an estimate of it so this is going + + align:start position:0% +take an estimate of it so this is going + + + align:start position:0% +take an estimate of it so this is going +to be a relatively small + + align:start position:0% +to be a relatively small + + + align:start position:0% +to be a relatively small +gun the + + align:start position:0% +gun the + + + align:start position:0% +gun the +uh mass of the total mass of the shot + + align:start position:0% + + + + align:start position:0% + +here time G is 10 + + align:start position:0% +here time G is 10 + + + align:start position:0% +here time G is 10 +lb so 10 lbs a shot a gallon of milk + + align:start position:0% +lb so 10 lbs a shot a gallon of milk + + + align:start position:0% +lb so 10 lbs a shot a gallon of milk +weighs eight pounds we're not this isn't + + align:start position:0% +weighs eight pounds we're not this isn't + + + align:start position:0% +weighs eight pounds we're not this isn't +a very big uh very big load and let's + + align:start position:0% +a very big uh very big load and let's + + + align:start position:0% +a very big uh very big load and let's +say that this Barrel here from here to + + align:start position:0% +say that this Barrel here from here to + + + align:start position:0% +say that this Barrel here from here to +here the acceleration length is 7 feet + + align:start position:0% +here the acceleration length is 7 feet + + + align:start position:0% +here the acceleration length is 7 feet +so that shots accelerated out the barrel + + align:start position:0% +so that shots accelerated out the barrel + + + align:start position:0% +so that shots accelerated out the barrel +over a distance of + + align:start position:0% +over a distance of + + + align:start position:0% +over a distance of +7t and it has a muzzle velocity an exit + + align:start position:0% + + + + align:start position:0% + +velocity of + + align:start position:0% +velocity of + + + align:start position:0% +velocity of +700 feet per + + align:start position:0% + + + + align:start position:0% + +second are most guns subsonic supersonic + + align:start position:0% +second are most guns subsonic supersonic + + + align:start position:0% +second are most guns subsonic supersonic +projectiles when they come out of guns + + align:start position:0% +projectiles when they come out of guns + + + align:start position:0% +projectiles when they come out of guns +thought about that I'm just asking + + align:start position:0% +thought about that I'm just asking + + + align:start position:0% +thought about that I'm just asking +seeing if you have a feeling for Speed + + align:start position:0% +seeing if you have a feeling for Speed + + + align:start position:0% +seeing if you have a feeling for Speed +how close to the speed of sound is + + align:start position:0% + + + + align:start position:0% + +that so speed of sound is about 1100 ft + + align:start position:0% +that so speed of sound is about 1100 ft + + + align:start position:0% +that so speed of sound is about 1100 ft +per second 340 m/ second so this is + + align:start position:0% +per second 340 m/ second so this is + + + align:start position:0% +per second 340 m/ second so this is +order of mack6 or something like + + align:start position:0% + + + + align:start position:0% + +that something like 6 not 06 0.6 so + + align:start position:0% +that something like 6 not 06 0.6 so + + + align:start position:0% +that something like 6 not 06 0.6 so +about 60% of the speed is down that's + + align:start position:0% +about 60% of the speed is down that's + + + align:start position:0% +about 60% of the speed is down that's +kind of slow actually as guns + + align:start position:0% + + + + align:start position:0% + +go so it the uh initial velocity the + + align:start position:0% +go so it the uh initial velocity the + + + align:start position:0% +go so it the uh initial velocity the +shots just sitting + + align:start position:0% +shots just sitting + + + align:start position:0% +shots just sitting +there is zero the final + + align:start position:0% +there is zero the final + + + align:start position:0% +there is zero the final +velocity is + + align:start position:0% +velocity is + + + align:start position:0% +velocity is +700 feet per second the average velocity + + align:start position:0% +700 feet per second the average velocity + + + align:start position:0% +700 feet per second the average velocity +which I'm going to need for a second + + align:start position:0% +which I'm going to need for a second + + + align:start position:0% +which I'm going to need for a second +because I'm just making some estimates + + align:start position:0% +because I'm just making some estimates + + + align:start position:0% +because I'm just making some estimates +here the average velocity average of 0 + + + align:start position:0% +here the average velocity average of 0 + + + + align:start position:0% +here the average velocity average of 0 + +700 is 350 ft per + + align:start position:0% +700 is 350 ft per + + + align:start position:0% +700 is 350 ft per +second to do the reason I need this is I + + align:start position:0% +second to do the reason I need this is I + + + align:start position:0% +second to do the reason I need this is I +need to estimate the delta T how long + + align:start position:0% +need to estimate the delta T how long + + + align:start position:0% +need to estimate the delta T how long +does it take to get the shot out of the + + align:start position:0% + + + + align:start position:0% + +barrel so distance equals rate times + + align:start position:0% +barrel so distance equals rate times + + + align:start position:0% +barrel so distance equals rate times +time right so the uh uh V + + align:start position:0% +time right so the uh uh V + + + align:start position:0% +time right so the uh uh V +average time delta T equals 7 + + align:start position:0% +average time delta T equals 7 + + + align:start position:0% +average time delta T equals 7 +ft at 350 ft per second you find out + + align:start position:0% +ft at 350 ft per second you find out + + + align:start position:0% +ft at 350 ft per second you find out +delta T is about 02 + + align:start position:0% + + + + align:start position:0% + +seconds so it gets out the barrel pretty + + align:start position:0% +seconds so it gets out the barrel pretty + + + align:start position:0% +seconds so it gets out the barrel pretty +quickly 0.02 seconds 20 + + align:start position:0% +quickly 0.02 seconds 20 + + + align:start position:0% +quickly 0.02 seconds 20 +milliseconds now that powder when it + + align:start position:0% +milliseconds now that powder when it + + + align:start position:0% +milliseconds now that powder when it +goes off it's putting a lot of forces on + + align:start position:0% +goes off it's putting a lot of forces on + + + align:start position:0% +goes off it's putting a lot of forces on +the + + align:start position:0% +the + + + align:start position:0% +the +shot so the total force on the shots + + align:start position:0% +shot so the total force on the shots + + + align:start position:0% +shot so the total force on the shots +5,000 PBS what's the reaction force on + + align:start position:0% +5,000 PBS what's the reaction force on + + + align:start position:0% +5,000 PBS what's the reaction force on +the cannon + + align:start position:0% + + + + align:start position:0% + +so we're going to going to apply a + + align:start position:0% +so we're going to going to apply a + + + align:start position:0% +so we're going to going to apply a +principle here that we talked about + + align:start position:0% +principle here that we talked about + + + align:start position:0% +principle here that we talked about +earlier Newton Newton had three + + align:start position:0% +earlier Newton Newton had three + + + align:start position:0% +earlier Newton Newton had three +laws this is a group this is this + + align:start position:0% +laws this is a group this is this + + + align:start position:0% +laws this is a group this is this +massive balls in + + align:start position:0% +massive balls in + + + align:start position:0% +massive balls in +there the hot exploding gases are + + align:start position:0% +there the hot exploding gases are + + + align:start position:0% +there the hot exploding gases are +pushing them out the barrel what must be + + align:start position:0% +pushing them out the barrel what must be + + + align:start position:0% +pushing them out the barrel what must be +the push of the same gas on the cannon + + align:start position:0% +the push of the same gas on the cannon + + + align:start position:0% +the push of the same gas on the cannon +that's containing it equal opposite + + align:start position:0% +that's containing it equal opposite + + + align:start position:0% +that's containing it equal opposite +equal and opposite Newton's third law + + align:start position:0% +equal and opposite Newton's third law + + + align:start position:0% +equal and opposite Newton's third law +right so the reaction the reaction force + + align:start position:0% +right so the reaction the reaction force + + + align:start position:0% +right so the reaction the reaction force +that we're looking for is minus the + + align:start position:0% +that we're looking for is minus the + + + align:start position:0% +that we're looking for is minus the +force that it takes to get the shot out + + align:start position:0% +force that it takes to get the shot out + + + align:start position:0% +force that it takes to get the shot out +the barrel + + align:start position:0% +the barrel + + + align:start position:0% +the barrel +okay so force on the + + align:start position:0% +okay so force on the + + + align:start position:0% +okay so force on the +balls on the + + align:start position:0% +balls on the + + + align:start position:0% +balls on the +shot minus the reaction force and that's + + align:start position:0% +shot minus the reaction force and that's + + + align:start position:0% +shot minus the reaction force and that's +Newton's third law + + align:start position:0% + + + + align:start position:0% + +okay so we're almost + + align:start position:0% +okay so we're almost + + + align:start position:0% +okay so we're almost +there but just applying now this concept + + align:start position:0% +there but just applying now this concept + + + align:start position:0% +there but just applying now this concept +of impulse and + + align:start position:0% + + + + align:start position:0% + +momentum so now we can say the integral + + align:start position:0% +momentum so now we can say the integral + + + align:start position:0% +momentum so now we can say the integral +and this is the summation you got a + + align:start position:0% +and this is the summation you got a + + + align:start position:0% +and this is the summation you got a +whole bunch of balls in there they're + + align:start position:0% +whole bunch of balls in there they're + + + align:start position:0% +whole bunch of balls in there they're +all got forces on them but we're + + align:start position:0% +all got forces on them but we're + + + align:start position:0% +all got forces on them but we're +treating the group of balls as a system + + align:start position:0% +treating the group of balls as a system + + + align:start position:0% +treating the group of balls as a system +so we can we can use this notion of the + + align:start position:0% +so we can we can use this notion of the + + + align:start position:0% +so we can we can use this notion of the +ma total mass times velocity of the + + align:start position:0% +ma total mass times velocity of the + + + align:start position:0% +ma total mass times velocity of the +center of gravity to do this problem + + align:start position:0% + + + + align:start position:0% + +so this is the force on all of these + + align:start position:0% +so this is the force on all of these + + + align:start position:0% +so this is the force on all of these +little + + align:start position:0% + + + + align:start position:0% + +balls integrated over + + align:start position:0% +balls integrated over + + + align:start position:0% +balls integrated over +time it's going to be the mass total of + + align:start position:0% +time it's going to be the mass total of + + + align:start position:0% +time it's going to be the mass total of +the balls times the change in the + + align:start position:0% +the balls times the change in the + + + align:start position:0% +the balls times the change in the +velocity of the center of gravity the + + align:start position:0% +velocity of the center of gravity the + + + align:start position:0% +velocity of the center of gravity the +final velocity minus the initial + + align:start position:0% +final velocity minus the initial + + + align:start position:0% +final velocity minus the initial +velocity + + align:start position:0% +velocity + + + align:start position:0% +velocity +this is + + align:start position:0% +this is + + + align:start position:0% +this is +zero okay we know this we know + + align:start position:0% +zero okay we know this we know + + + align:start position:0% +zero okay we know this we know +this so This Mt is the 10 lbs over G we + + align:start position:0% +this so This Mt is the 10 lbs over G we + + + align:start position:0% +this so This Mt is the 10 lbs over G we +know this is 700 feet per second we know + + align:start position:0% +know this is 700 feet per second we know + + + align:start position:0% +know this is 700 feet per second we know +that all of this mounts up to the force + + align:start position:0% +that all of this mounts up to the force + + + align:start position:0% +that all of this mounts up to the force +external on the + + align:start position:0% +external on the + + + align:start position:0% +external on the +group delta T + + align:start position:0% + + + + align:start position:0% + +and this is the weight of the ball W + + align:start position:0% +and this is the weight of the ball W + + + align:start position:0% +and this is the weight of the ball W +over + + align:start position:0% +over + + + align:start position:0% +over +G and this is + + align:start position:0% +G and this is + + + align:start position:0% +G and this is +700 feet per + + align:start position:0% +700 feet per + + + align:start position:0% +700 feet per +second that's 10 PBS divided by gravity + + align:start position:0% + + + + align:start position:0% + +700 ft per second and if you work out + + align:start position:0% +700 ft per second and if you work out + + + align:start position:0% +700 ft per second and if you work out +those numbers you + + align:start position:0% +those numbers you + + + align:start position:0% +those numbers you +get + + align:start position:0% +get + + + align:start position:0% +get +10,870 + + align:start position:0% + + + + align:start position:0% + +lb now is this is an + + align:start position:0% + + + + align:start position:0% + +average force + + align:start position:0% + + + + align:start position:0% + +right because we at delta T is the + + align:start position:0% +right because we at delta T is the + + + align:start position:0% +right because we at delta T is the +length of time it took assuming we had + + align:start position:0% +length of time it took assuming we had + + + align:start position:0% +length of time it took assuming we had +some one we assumed an average velocity + + align:start position:0% +some one we assumed an average velocity + + + align:start position:0% +some one we assumed an average velocity +going down the barrel so the peak force + + align:start position:0% +going down the barrel so the peak force + + + align:start position:0% +going down the barrel so the peak force +is probably higher than this and the + + align:start position:0% +is probably higher than this and the + + + align:start position:0% +is probably higher than this and the +pressure of the barrel probably isn't + + align:start position:0% +pressure of the barrel probably isn't + + + align:start position:0% +pressure of the barrel probably isn't +constant this actually isn't a bad + + align:start position:0% +constant this actually isn't a bad + + + align:start position:0% +constant this actually isn't a bad +estimate if you know the muzzle velocity + + align:start position:0% +estimate if you know the muzzle velocity + + + align:start position:0% +estimate if you know the muzzle velocity +which you could figure out probably from + + align:start position:0% +which you could figure out probably from + + + align:start position:0% +which you could figure out probably from +the distance it goes and things like + + align:start position:0% +the distance it goes and things like + + + align:start position:0% +the distance it goes and things like +that you can make this estimate so + + align:start position:0% +that you can make this estimate so + + + align:start position:0% +that you can make this estimate so +10,000 pounds of reaction force + + align:start position:0% +10,000 pounds of reaction force + + + align:start position:0% +10,000 pounds of reaction force +is quite a lot this is this is a dinky + + align:start position:0% +is quite a lot this is this is a dinky + + + align:start position:0% +is quite a lot this is this is a dinky +gun 10 this is 10 lbs of shot is not + + align:start position:0% +gun 10 this is 10 lbs of shot is not + + + align:start position:0% +gun 10 this is 10 lbs of shot is not +much so that's this is this is the force + + align:start position:0% +much so that's this is this is the force + + + align:start position:0% +much so that's this is this is the force +to get the balls out the barrel if it's + + align:start position:0% +to get the balls out the barrel if it's + + + align:start position:0% +to get the balls out the barrel if it's +positive what's the reaction + + align:start position:0% + + + + align:start position:0% + +force minus + + align:start position:0% +force minus + + + align:start position:0% +force minus +10,870 and all through this I've been + + align:start position:0% +10,870 and all through this I've been + + + align:start position:0% +10,870 and all through this I've been +doing this in a single Vector Direction + + align:start position:0% +doing this in a single Vector Direction + + + align:start position:0% +doing this in a single Vector Direction +so I would have set up my coordinate + + align:start position:0% +so I would have set up my coordinate + + + align:start position:0% +so I would have set up my coordinate +system like here's o this is the X + + align:start position:0% +system like here's o this is the X + + + align:start position:0% +system like here's o this is the X +Direction y direction so this is + + align:start position:0% +Direction y direction so this is + + + align:start position:0% +Direction y direction so this is +obviously in the positive X direction is + + align:start position:0% +obviously in the positive X direction is + + + align:start position:0% +obviously in the positive X direction is +what I've lined up my positive + + align:start position:0% +what I've lined up my positive + + + align:start position:0% +what I've lined up my positive +velocities and positive forces to be so + + align:start position:0% +velocities and positive forces to be so + + + align:start position:0% +velocities and positive forces to be so +just a really simple way one of the kind + + align:start position:0% +just a really simple way one of the kind + + + align:start position:0% +just a really simple way one of the kind +of ways in which you use this notion of + + align:start position:0% +of ways in which you use this notion of + + + align:start position:0% +of ways in which you use this notion of +impulse and momentum but you can use it + + align:start position:0% +impulse and momentum but you can use it + + + align:start position:0% +impulse and momentum but you can use it +to make estimates too + + align:start position:0% + + + + align:start position:0% + +okay and if you ever fired a + + align:start position:0% +okay and if you ever fired a + + + align:start position:0% +okay and if you ever fired a +shotgun not yeah any kick right so what + + align:start position:0% +shotgun not yeah any kick right so what + + + align:start position:0% +shotgun not yeah any kick right so what +gauge shotgun did you + + align:start position:0% +gauge shotgun did you + + + align:start position:0% +gauge shotgun did you +fire you know know + + align:start position:0% +fire you know know + + + align:start position:0% +fire you know know +okay okay 12 gaug shotgun you know the + + align:start position:0% +okay okay 12 gaug shotgun you know the + + + align:start position:0% +okay okay 12 gaug shotgun you know the +the the cartridge is about 3/4 of an + + align:start position:0% +the the cartridge is about 3/4 of an + + + align:start position:0% +the the cartridge is about 3/4 of an +inch diameter and it probably has a + + align:start position:0% +inch diameter and it probably has a + + + align:start position:0% +inch diameter and it probably has a +little amount of powder in there it + + align:start position:0% +little amount of powder in there it + + + align:start position:0% +little amount of powder in there it +amounts up to about that much stuff but + + align:start position:0% +amounts up to about that much stuff but + + + align:start position:0% +amounts up to about that much stuff but +it can give you a bruise in the shoulder + + align:start position:0% +it can give you a bruise in the shoulder + + + align:start position:0% +it can give you a bruise in the shoulder +if you don't hold it + + align:start position:0% +if you don't hold it + + + align:start position:0% +if you don't hold it +right so that's what that's what this is + + align:start position:0% +right so that's what that's what this is + + + align:start position:0% +right so that's what that's what this is +about all right so this kind of a quick + + align:start position:0% +about all right so this kind of a quick + + + align:start position:0% +about all right so this kind of a quick +review uh you've done lots of + + align:start position:0% +review uh you've done lots of + + + align:start position:0% +review uh you've done lots of +conservational momentum problems in your + + align:start position:0% +conservational momentum problems in your + + + align:start position:0% +conservational momentum problems in your +time the homework set this this time has + + align:start position:0% +time the homework set this this time has + + + align:start position:0% +time the homework set this this time has +two or three problems on it that are + + align:start position:0% +two or three problems on it that are + + + align:start position:0% +two or three problems on it that are +conservation or momentum linear momentum + + align:start position:0% +conservation or momentum linear momentum + + + align:start position:0% +conservation or momentum linear momentum +but now I want to move on to talking + + align:start position:0% +but now I want to move on to talking + + + align:start position:0% +but now I want to move on to talking +about angular momentum and angular + + align:start position:0% +about angular momentum and angular + + + align:start position:0% +about angular momentum and angular +momentum in a way in which you probably + + align:start position:0% +momentum in a way in which you probably + + + align:start position:0% +momentum in a way in which you probably +haven't done angular momentum problems + + align:start position:0% +haven't done angular momentum problems + + + align:start position:0% +haven't done angular momentum problems +before so anything about La last thing + + align:start position:0% +before so anything about La last thing + + + align:start position:0% +before so anything about La last thing +on this so mostly this I want you to + + align:start position:0% +on this so mostly this I want you to + + + align:start position:0% +on this so mostly this I want you to +read the read the chapter I think it's + + align:start position:0% +read the read the chapter I think it's + + + align:start position:0% +read the read the chapter I think it's +chapter + + align:start position:0% +chapter + + + align:start position:0% +chapter +15 first few sections of it are on + + align:start position:0% +15 first few sections of it are on + + + align:start position:0% +15 first few sections of it are on +linear momentum the last few sections on + + align:start position:0% +linear momentum the last few sections on + + + align:start position:0% +linear momentum the last few sections on +angular momentum go read them and just + + align:start position:0% +angular momentum go read them and just + + + align:start position:0% +angular momentum go read them and just +work the problems that's where they + + align:start position:0% +work the problems that's where they + + + align:start position:0% +work the problems that's where they +that's where you'll get most of your + + align:start position:0% +that's where you'll get most of your + + + align:start position:0% +that's where you'll get most of your +refresher is work is doing the practice + + align:start position:0% +refresher is work is doing the practice + + + align:start position:0% +refresher is work is doing the practice +problems okay angular momentum + + align:start position:0% + + + + align:start position:0% + +so we'll start with particle we're very + + align:start position:0% +so we'll start with particle we're very + + + align:start position:0% +so we'll start with particle we're very +rapidly going to get to rigid + + align:start position:0% + + + + align:start position:0% + +bodies now Mo many times you've done + + align:start position:0% +bodies now Mo many times you've done + + + align:start position:0% +bodies now Mo many times you've done +angular momentum problems before mostly + + align:start position:0% +angular momentum problems before mostly + + + align:start position:0% +angular momentum problems before mostly +rotations about fixed axes so here's our + + align:start position:0% +rotations about fixed axes so here's our + + + align:start position:0% +rotations about fixed axes so here's our +inertial frame fixed + + align:start position:0% +inertial frame fixed + + + align:start position:0% +inertial frame fixed +XY and you have a particle out + + align:start position:0% +XY and you have a particle out + + + align:start position:0% +XY and you have a particle out +here and and it just has some mass + + align:start position:0% +here and and it just has some mass + + + align:start position:0% +here and and it just has some mass +m and it has some total force on it the + + align:start position:0% +m and it has some total force on it the + + + align:start position:0% +m and it has some total force on it the +force and this is the particle is + + align:start position:0% +force and this is the particle is + + + align:start position:0% +force and this is the particle is +located at B here so the force at B + + align:start position:0% +located at B here so the force at B + + + align:start position:0% +located at B here so the force at B +total Force at B just some + + align:start position:0% +total Force at B just some + + + align:start position:0% +total Force at B just some +Vector it also is traveling with some + + align:start position:0% +Vector it also is traveling with some + + + align:start position:0% +Vector it also is traveling with some +velocity at that instant in time so it + + align:start position:0% +velocity at that instant in time so it + + + align:start position:0% +velocity at that instant in time so it +has momentum okay and the momentum is + + align:start position:0% +has momentum okay and the momentum is + + + align:start position:0% +has momentum okay and the momentum is +p of this particle at + + align:start position:0% +p of this particle at + + + align:start position:0% +p of this particle at +B with respect to 2 + + align:start position:0% + + + + align:start position:0% + +O and I'd like to the standard + + align:start position:0% +O and I'd like to the standard + + + align:start position:0% +O and I'd like to the standard +expression then for the angular + + align:start position:0% +expression then for the angular + + + align:start position:0% +expression then for the angular +momentum of this particle at + + align:start position:0% +momentum of this particle at + + + align:start position:0% +momentum of this particle at +B with respect to + + align:start position:0% + + + + align:start position:0% + +O we have a position Vector here + + align:start position:0% +O we have a position Vector here + + + align:start position:0% +O we have a position Vector here +RB which we've used lots of times by now + + align:start position:0% +RB which we've used lots of times by now + + + align:start position:0% +RB which we've used lots of times by now +is just the cross product of the + + align:start position:0% +is just the cross product of the + + + align:start position:0% +is just the cross product of the +position + + align:start position:0% +position + + + align:start position:0% +position +Vector with the linear + + align:start position:0% + + + + align:start position:0% + +momentum and that's just that's the + + align:start position:0% +momentum and that's just that's the + + + align:start position:0% +momentum and that's just that's the +definition of angular momentum I'm using + + align:start position:0% +definition of angular momentum I'm using + + + align:start position:0% +definition of angular momentum I'm using +a lowercase H here because I'm going to + + align:start position:0% +a lowercase H here because I'm going to + + + align:start position:0% +a lowercase H here because I'm going to +do that to indicate single particles and + + align:start position:0% +do that to indicate single particles and + + + align:start position:0% +do that to indicate single particles and +I use a capital H later on when we're + + align:start position:0% +I use a capital H later on when we're + + + align:start position:0% +I use a capital H later on when we're +referring to rigid bodies so the angular + + align:start position:0% +referring to rigid bodies so the angular + + + align:start position:0% +referring to rigid bodies so the angular +momentum of this particle + + align:start position:0% +momentum of this particle + + + align:start position:0% +momentum of this particle +with respect to this point is given by + + align:start position:0% + + + + align:start position:0% + +that and you've where you've used this + + align:start position:0% +that and you've where you've used this + + + align:start position:0% +that and you've where you've used this +before then is the derivative of HB with + + align:start position:0% +before then is the derivative of HB with + + + align:start position:0% +before then is the derivative of HB with +respect to + + align:start position:0% +respect to + + + align:start position:0% +respect to +O DT + + align:start position:0% +O DT + + + align:start position:0% +O DT +is what is that and remember what does + + align:start position:0% +is what is that and remember what does + + + align:start position:0% +is what is that and remember what does +this give you the time rate of change of + + align:start position:0% +this give you the time rate of change of + + + align:start position:0% +this give you the time rate of change of +the angular momentum is the torque right + + align:start position:0% +the angular momentum is the torque right + + + align:start position:0% +the angular momentum is the torque right +and it's the torque it's a sum of the + + align:start position:0% +and it's the torque it's a sum of the + + + align:start position:0% +and it's the torque it's a sum of the +torqus + + align:start position:0% +torqus + + + align:start position:0% +torqus +applied on that object with respect + + align:start position:0% +applied on that object with respect + + + align:start position:0% +applied on that object with respect +to the coordinate system in which you're + + align:start position:0% +to the coordinate system in which you're + + + align:start position:0% +to the coordinate system in which you're +Computing the angular momentum so that's + + align:start position:0% +Computing the angular momentum so that's + + + align:start position:0% +Computing the angular momentum so that's +you've used this formula many times and + + align:start position:0% +you've used this formula many times and + + + align:start position:0% +you've used this formula many times and +in planer motion where you only have one + + align:start position:0% +in planer motion where you only have one + + + align:start position:0% +in planer motion where you only have one +axis of rotation usually the z-axis of + + align:start position:0% +axis of rotation usually the z-axis of + + + align:start position:0% +axis of rotation usually the z-axis of +rotation you usually usually would write + + align:start position:0% +rotation you usually usually would write + + + align:start position:0% +rotation you usually usually would write +this as I Theta double dot right in the + + align:start position:0% +this as I Theta double dot right in the + + + align:start position:0% +this as I Theta double dot right in the +simplest form if it's a rigid body it + + align:start position:0% +simplest form if it's a rigid body it + + + align:start position:0% +simplest form if it's a rigid body it +has the mass moment of inertia times + + align:start position:0% +has the mass moment of inertia times + + + align:start position:0% +has the mass moment of inertia times +Theta double dot is equal to the sum of + + align:start position:0% +Theta double dot is equal to the sum of + + + align:start position:0% +Theta double dot is equal to the sum of +the external torque so that's where + + align:start position:0% +the external torque so that's where + + + align:start position:0% +the external torque so that's where +you've met this before but for the + + align:start position:0% +you've met this before but for the + + + align:start position:0% +you've met this before but for the +moment this is just a particle let's + + align:start position:0% +moment this is just a particle let's + + + align:start position:0% +moment this is just a particle let's +stick with a + + align:start position:0% +stick with a + + + align:start position:0% +stick with a +particle so the piece that's new here + + align:start position:0% +particle so the piece that's new here + + + align:start position:0% +particle so the piece that's new here +probably new for you is that um what if + + align:start position:0% +probably new for you is that um what if + + + align:start position:0% +probably new for you is that um what if +I want to + + align:start position:0% +I want to + + + align:start position:0% +I want to +know the angular momentum with respect + + align:start position:0% +know the angular momentum with respect + + + align:start position:0% +know the angular momentum with respect +to another point so here's a point + + align:start position:0% + + + + align:start position:0% + +a and I'd like to compute + + align:start position:0% +a and I'd like to compute + + + align:start position:0% +a and I'd like to compute +h of B with respect to + + align:start position:0% +h of B with respect to + + + align:start position:0% +h of B with respect to +a well that's + + align:start position:0% +a well that's + + + align:start position:0% +a well that's +r b with respect to + + align:start position:0% +r b with respect to + + + align:start position:0% +r b with respect to +a cross p + + align:start position:0% +a cross p + + + align:start position:0% +a cross p +b with respect to O and this is really + + align:start position:0% +b with respect to O and this is really + + + align:start position:0% +b with respect to O and this is really +easy to forget the momentum is always + + align:start position:0% +easy to forget the momentum is always + + + align:start position:0% +easy to forget the momentum is always +calculated with respect to your inertial + + align:start position:0% +calculated with respect to your inertial + + + align:start position:0% +calculated with respect to your inertial +frame and that's why I keeping this with + + align:start position:0% +frame and that's why I keeping this with + + + align:start position:0% +frame and that's why I keeping this with +respect to and telling you what the + + align:start position:0% +respect to and telling you what the + + + align:start position:0% +respect to and telling you what the +frame name is is pretty important but + + align:start position:0% +frame name is is pretty important but + + + align:start position:0% +frame name is is pretty important but +we're out here at some arbitrary Point + + align:start position:0% +we're out here at some arbitrary Point + + + align:start position:0% +we're out here at some arbitrary Point +Computing the C the cross product of the + + align:start position:0% +Computing the C the cross product of the + + + align:start position:0% +Computing the C the cross product of the +position Vector from this arbitrary + + align:start position:0% +position Vector from this arbitrary + + + align:start position:0% +position Vector from this arbitrary +point to this moving mass and we're + + align:start position:0% +point to this moving mass and we're + + + align:start position:0% +point to this moving mass and we're +defining this is just a definition + + align:start position:0% +defining this is just a definition + + + align:start position:0% +defining this is just a definition +defining the angular momentum with + + align:start position:0% +defining the angular momentum with + + + align:start position:0% +defining the angular momentum with +respect to this point a as RBA cross p p + + align:start position:0% +respect to this point a as RBA cross p p + + + align:start position:0% +respect to this point a as RBA cross p p +with respect to O all right + + align:start position:0% + + + + align:start position:0% + +and what I want to get to is now is the + + align:start position:0% + + + + align:start position:0% + +torque on this system on this part + + align:start position:0% +torque on this system on this part + + + align:start position:0% +torque on this system on this part +around this particle B with respect to + + align:start position:0% + + + + align:start position:0% + +a is the time rate of change of + + align:start position:0% + + + + align:start position:0% + +HBA with respect to T but now it's a + + align:start position:0% +HBA with respect to T but now it's a + + + align:start position:0% +HBA with respect to T but now it's a +little more complicated plus the + + align:start position:0% +little more complicated plus the + + + align:start position:0% +little more complicated plus the +velocity of a with respect to + + align:start position:0% +velocity of a with respect to + + + align:start position:0% +velocity of a with respect to +O all vectors + + align:start position:0% +O all vectors + + + align:start position:0% +O all vectors +cross p b with respect to O messy + + align:start position:0% + + + + align:start position:0% + +term I was trying to think of an example + + align:start position:0% +term I was trying to think of an example + + + align:start position:0% +term I was trying to think of an example +where you + + align:start position:0% +where you + + + align:start position:0% +where you +uh you might want to do this + + align:start position:0% + + + + align:start position:0% + +so imagine that you've got an arm which + + align:start position:0% +so imagine that you've got an arm which + + + align:start position:0% +so imagine that you've got an arm which +can + + align:start position:0% +can + + + align:start position:0% +can +rotate you know might be on a robot or + + align:start position:0% +rotate you know might be on a robot or + + + align:start position:0% +rotate you know might be on a robot or +something like that and it has attached + + align:start position:0% +something like that and it has attached + + + align:start position:0% +something like that and it has attached +to it another arm with a mass on + + align:start position:0% +to it another arm with a mass on + + + align:start position:0% +to it another arm with a mass on +it and you've got a motor here which can + + align:start position:0% +it and you've got a motor here which can + + + align:start position:0% +it and you've got a motor here which can +make this + + align:start position:0% +make this + + + align:start position:0% +make this +rotate and you're trying to design the + + align:start position:0% +rotate and you're trying to design the + + + align:start position:0% +rotate and you're trying to design the +motor has has to be able to put out a + + align:start position:0% +motor has has to be able to put out a + + + align:start position:0% +motor has has to be able to put out a +certain amount of + + align:start position:0% +certain amount of + + + align:start position:0% +certain amount of +torque so this is O this is B this is a + + align:start position:0% +torque so this is O this is B this is a + + + align:start position:0% +torque so this is O this is B this is a +and you actually I want to know the + + align:start position:0% +and you actually I want to know the + + + align:start position:0% +and you actually I want to know the +torque required in this motor to drive + + align:start position:0% +torque required in this motor to drive + + + align:start position:0% +torque required in this motor to drive +this thing around but the motor is here + + align:start position:0% +this thing around but the motor is here + + + align:start position:0% +this thing around but the motor is here +and it only cares about what it feels so + + align:start position:0% +and it only cares about what it feels so + + + align:start position:0% +and it only cares about what it feels so +the torque at this point to drive this + + align:start position:0% +the torque at this point to drive this + + + align:start position:0% +the torque at this point to drive this +thing but this whole system is now in + + align:start position:0% +thing but this whole system is now in + + + align:start position:0% +thing but this whole system is now in +motion you'd have to use this formula + + align:start position:0% +motion you'd have to use this formula + + + align:start position:0% +motion you'd have to use this formula +okay so there are practical times when + + align:start position:0% +okay so there are practical times when + + + align:start position:0% +okay so there are practical times when +you'd like to be able to be able to + + align:start position:0% +you'd like to be able to be able to + + + align:start position:0% +you'd like to be able to be able to +calculate something like + + align:start position:0% + + + + align:start position:0% + +this so there's a I'm going to show you + + align:start position:0% + + + + align:start position:0% + +the a very brief derivation of this and + + align:start position:0% +the a very brief derivation of this and + + + align:start position:0% +the a very brief derivation of this and +but just so you get a feeling for where + + align:start position:0% +but just so you get a feeling for where + + + align:start position:0% +but just so you get a feeling for where +this comes from because there's a couple + + align:start position:0% +this comes from because there's a couple + + + align:start position:0% +this comes from because there's a couple +of outcomes that are very important to + + align:start position:0% + + + + align:start position:0% + +us so the sum of the forces there at + + align:start position:0% +us so the sum of the forces there at + + + align:start position:0% +us so the sum of the forces there at +those forces at + + align:start position:0% + + + + align:start position:0% + +B give you the time rate of + + align:start position:0% +B give you the time rate of + + + align:start position:0% +B give you the time rate of +change of the + + align:start position:0% +change of the + + + align:start position:0% +change of the +momentum at B with respect to O this is + + align:start position:0% +momentum at B with respect to O this is + + + align:start position:0% +momentum at B with respect to O this is +that moment momentum Vector of our + + align:start position:0% +that moment momentum Vector of our + + + align:start position:0% +that moment momentum Vector of our +particle okay and this FB this is a + + align:start position:0% +particle okay and this FB this is a + + + align:start position:0% +particle okay and this FB this is a +total external forces acting on the + + align:start position:0% + + + + align:start position:0% + +particle we know that's + + align:start position:0% +particle we know that's + + + align:start position:0% +particle we know that's +m a single particle times the + + align:start position:0% +m a single particle times the + + + align:start position:0% +m a single particle times the +velocity of + + align:start position:0% + + + + align:start position:0% + +uh that certainly could be right + + align:start position:0% + + + + align:start position:0% + +times that's our familiar formula for + + align:start position:0% +times that's our familiar formula for + + + align:start position:0% +times that's our familiar formula for +fals ma right so the time derivative of + + align:start position:0% +fals ma right so the time derivative of + + + align:start position:0% +fals ma right so the time derivative of +the linear momentum gives you this and + + align:start position:0% +the linear momentum gives you this and + + + align:start position:0% +the linear momentum gives you this and +the + + align:start position:0% +the + + + align:start position:0% +the +torque of B with respect to + + align:start position:0% +torque of B with respect to + + + align:start position:0% +torque of B with respect to +a is r b a cross I'm this total I'm + + align:start position:0% +a is r b a cross I'm this total I'm + + + align:start position:0% +a is r b a cross I'm this total I'm +going let this just be a total Vector + + align:start position:0% +going let this just be a total Vector + + + align:start position:0% +going let this just be a total Vector +I'll call it f + + align:start position:0% +I'll call it f + + + align:start position:0% +I'll call it f +B it's a vector the torque with respect + + align:start position:0% +B it's a vector the torque with respect + + + align:start position:0% +B it's a vector the torque with respect +to a is just RBA cross this total + + align:start position:0% +to a is just RBA cross this total + + + align:start position:0% +to a is just RBA cross this total +external Force + + align:start position:0% +external Force + + + align:start position:0% +external Force +okay and + + align:start position:0% +okay and + + + align:start position:0% +okay and +that's + + align:start position:0% +that's + + + align:start position:0% +that's +R + + align:start position:0% +R + + + align:start position:0% +R +ba + + align:start position:0% +ba + + + align:start position:0% +ba +cross the time + + align:start position:0% +cross the time + + + align:start position:0% +cross the time +derivative + + align:start position:0% +derivative + + + align:start position:0% +derivative +of + + align:start position:0% + + + + align:start position:0% + +PBO because the forces give us R which + + align:start position:0% +PBO because the forces give us R which + + + align:start position:0% +PBO because the forces give us R which +is from the time rate of change of the + + align:start position:0% +is from the time rate of change of the + + + align:start position:0% +is from the time rate of change of the +linear momentum of that + + align:start position:0% +linear momentum of that + + + align:start position:0% +linear momentum of that +particle so I can say it like this but + + align:start position:0% +particle so I can say it like this but + + + align:start position:0% +particle so I can say it like this but +now this there's just a little + + align:start position:0% +now this there's just a little + + + align:start position:0% +now this there's just a little +Vector + + align:start position:0% +Vector + + + align:start position:0% +Vector +identity + + align:start position:0% +identity + + + align:start position:0% +identity +for products of vectors that I'm going + + align:start position:0% +for products of vectors that I'm going + + + align:start position:0% +for products of vectors that I'm going +to take advantage of and I'll call this + + align:start position:0% +to take advantage of and I'll call this + + + align:start position:0% +to take advantage of and I'll call this +Q so Q + + align:start position:0% + + + + align:start position:0% + +so Q is of the form and I'm going to say + + align:start position:0% +so Q is of the form and I'm going to say + + + align:start position:0% +so Q is of the form and I'm going to say +m this is a Quant a vector a and this is + + align:start position:0% +m this is a Quant a vector a and this is + + + align:start position:0% +m this is a Quant a vector a and this is +a quantity a vector time derivative of a + + align:start position:0% +a quantity a vector time derivative of a + + + align:start position:0% +a quantity a vector time derivative of a +vector B it's a cross + + align:start position:0% +vector B it's a cross + + + align:start position:0% +vector B it's a cross +dbdt + + align:start position:0% +dbdt + + + align:start position:0% +dbdt +so there's a little identity that you + + align:start position:0% +so there's a little identity that you + + + align:start position:0% +so there's a little identity that you +can use it says a + + align:start position:0% +can use it says a + + + align:start position:0% +can use it says a +cross + + align:start position:0% +cross + + + align:start position:0% +cross +DB + + align:start position:0% +DB + + + align:start position:0% +DB +DT you can you can alternatively write + + align:start position:0% +DT you can you can alternatively write + + + align:start position:0% +DT you can you can alternatively write +that as the time + + align:start position:0% +that as the time + + + align:start position:0% +that as the time +derivative + + align:start position:0% +derivative + + + align:start position:0% +derivative +of A cross + + align:start position:0% +of A cross + + + align:start position:0% +of A cross +B + + align:start position:0% +B + + + align:start position:0% +B +minus time derivative of + + align:start position:0% + + + + align:start position:0% + +A cross + + align:start position:0% +A cross + + + align:start position:0% +A cross +B and if we're we're going to take + + align:start position:0% +B and if we're we're going to take + + + align:start position:0% +B and if we're we're going to take +advantage of this and just + + align:start position:0% +advantage of this and just + + + align:start position:0% +advantage of this and just +re construct this formula using + + align:start position:0% +re construct this formula using + + + align:start position:0% +re construct this formula using +this expression + + align:start position:0% + + + + align:start position:0% + +so that says torque with of B with + + align:start position:0% +so that says torque with of B with + + + align:start position:0% +so that says torque with of B with +respect to + + align:start position:0% + + + + align:start position:0% + +a the time derivative + + align:start position:0% + + + + align:start position:0% + +of + + align:start position:0% +of + + + align:start position:0% +of +RBA + + align:start position:0% +RBA + + + align:start position:0% +RBA +cross + + align:start position:0% + + + + align:start position:0% + +PBO minus the derivative of RBA + + align:start position:0% + + + + align:start position:0% + +cross + + align:start position:0% +cross + + + align:start position:0% +cross +PBF so we've just made this substitution + + align:start position:0% +PBF so we've just made this substitution + + + align:start position:0% +PBF so we've just made this substitution +down here in terms of RBA and + + align:start position:0% +down here in terms of RBA and + + + align:start position:0% +down here in terms of RBA and +PBO all + + align:start position:0% + + + + align:start position:0% + +vectors but we know that + + align:start position:0% + + + + align:start position:0% + +RBA from all the previous work we've + + align:start position:0% +RBA from all the previous work we've + + + align:start position:0% +RBA from all the previous work we've +done is just rbo minus r + + align:start position:0% + + + + align:start position:0% + +AO so the derivative of + + align:start position:0% + + + + align:start position:0% + +RBA with respect to + + align:start position:0% + + + + align:start position:0% + +time is + + align:start position:0% +time is + + + align:start position:0% +time is +VB minus + + align:start position:0% +VB minus + + + align:start position:0% +VB minus +V + + align:start position:0% +V + + + align:start position:0% +V +AO all right we're almost there we're + + align:start position:0% +AO all right we're almost there we're + + + align:start position:0% +AO all right we're almost there we're +almost there I'm going to need another + + align:start position:0% +almost there I'm going to need another + + + align:start position:0% +almost there I'm going to need another +board though + + align:start position:0% + + + + align:start position:0% + +this quantity here this is just + + align:start position:0% +this quantity here this is just + + + align:start position:0% +this quantity here this is just +h b a this is the angular momentum of + + align:start position:0% +h b a this is the angular momentum of + + + align:start position:0% +h b a this is the angular momentum of +the particle with respect to a it's just + + align:start position:0% +the particle with respect to a it's just + + + align:start position:0% +the particle with respect to a it's just +R cross B if you recall + + align:start position:0% + + + + align:start position:0% + +so then we can rewrite this expression + + align:start position:0% +so then we can rewrite this expression + + + align:start position:0% +so then we can rewrite this expression +for the torque + + align:start position:0% +for the torque + + + align:start position:0% +for the torque +as the time + + align:start position:0% +as the time + + + align:start position:0% +as the time +derivative of H of B with respect to a + + align:start position:0% +derivative of H of B with respect to a + + + align:start position:0% +derivative of H of B with respect to a +that's because of what I pointed out + + align:start position:0% +that's because of what I pointed out + + + align:start position:0% +that's because of what I pointed out +there and now this is + + align:start position:0% + + + + align:start position:0% + +minus VB o minus B + + align:start position:0% + + + + align:start position:0% + +AO cross P Bo o + + align:start position:0% + + + + align:start position:0% + +so P of B with respect to O is just + + align:start position:0% +so P of B with respect to O is just + + + align:start position:0% +so P of B with respect to O is just +m velocity of B with respect to O + + align:start position:0% +m velocity of B with respect to O + + + align:start position:0% +m velocity of B with respect to O +right so vbo cross PBO gives you what + + align:start position:0% +right so vbo cross PBO gives you what + + + align:start position:0% +right so vbo cross PBO gives you what +nothing get you zero because they're + + align:start position:0% +nothing get you zero because they're + + + align:start position:0% +nothing get you zero because they're +parallel to going they're exact they're + + align:start position:0% +parallel to going they're exact they're + + + align:start position:0% +parallel to going they're exact they're +in the same direction so this you only + + align:start position:0% +in the same direction so this you only + + + align:start position:0% +in the same direction so this you only +get a nonzero piece out of this minus + + align:start position:0% +get a nonzero piece out of this minus + + + align:start position:0% +get a nonzero piece out of this minus +time minus gives you a plus and you end + + align:start position:0% +time minus gives you a plus and you end + + + align:start position:0% +time minus gives you a plus and you end +up with + + align:start position:0% + + + + align:start position:0% + +and that's what we set out to + + align:start position:0% + + + + align:start position:0% + +find I said this is where I was trying + + align:start position:0% +find I said this is where I was trying + + + align:start position:0% +find I said this is where I was trying +to get and now we're + + align:start position:0% +to get and now we're + + + align:start position:0% +to get and now we're +there now the import importantly there's + + align:start position:0% +there now the import importantly there's + + + align:start position:0% +there now the import importantly there's +a couple of special cases of + + align:start position:0% +a couple of special cases of + + + align:start position:0% +a couple of special cases of +this this can be kind of a nuisance term + + align:start position:0% +this this can be kind of a nuisance term + + + align:start position:0% +this this can be kind of a nuisance term +to have to deal with lots of times you'd + + align:start position:0% +to have to deal with lots of times you'd + + + align:start position:0% +to have to deal with lots of times you'd +like to be able to get rid of it and + + align:start position:0% +like to be able to get rid of it and + + + align:start position:0% +like to be able to get rid of it and +just be able to go back to that Old + + align:start position:0% +just be able to go back to that Old + + + align:start position:0% +just be able to go back to that Old +Reliable formula torque is time rate of + + align:start position:0% +Reliable formula torque is time rate of + + + align:start position:0% +Reliable formula torque is time rate of +change of angular + + align:start position:0% +change of angular + + + align:start position:0% +change of angular +momentum so there are two obvious almost + + align:start position:0% +momentum so there are two obvious almost + + + align:start position:0% +momentum so there are two obvious almost +maybe obvious conditions in which this + + align:start position:0% +maybe obvious conditions in which this + + + align:start position:0% +maybe obvious conditions in which this +will go + + align:start position:0% +will go + + + align:start position:0% +will go +away what's the most obvious one + + align:start position:0% + + + + align:start position:0% + +of terms Zer something what did you say + + align:start position:0% +of terms Zer something what did you say + + + align:start position:0% +of terms Zer something what did you say +is zero one of the terms well yeah this + + align:start position:0% +is zero one of the terms well yeah this + + + align:start position:0% +is zero one of the terms well yeah this +this this term presumably not this guy + + align:start position:0% +this this term presumably not this guy + + + align:start position:0% +this this term presumably not this guy +if this is + + align:start position:0% + + + + align:start position:0% + +zero is just back to our old familiar + + align:start position:0% +zero is just back to our old familiar + + + align:start position:0% +zero is just back to our old familiar +formula + + align:start position:0% + + + + align:start position:0% + +that's one case the case + + align:start position:0% + + + + align:start position:0% + +one but now actually this this is a + + align:start position:0% +one but now actually this this is a + + + align:start position:0% +one but now actually this this is a +really important + + align:start position:0% +really important + + + align:start position:0% +really important +result + + align:start position:0% +result + + + align:start position:0% +result +because a can be + + align:start position:0% +because a can be + + + align:start position:0% +because a can be +anywhere as long as it's not + + align:start position:0% +anywhere as long as it's not + + + align:start position:0% +anywhere as long as it's not +moving and so this allows you to do + + align:start position:0% +moving and so this allows you to do + + + align:start position:0% +moving and so this allows you to do +things talk about rotations about fixed + + align:start position:0% +things talk about rotations about fixed + + + align:start position:0% +things talk about rotations about fixed +axes that aren't at the center of + + align:start position:0% +axes that aren't at the center of + + + align:start position:0% +axes that aren't at the center of +mass right so if you have a fixed axis + + align:start position:0% +mass right so if you have a fixed axis + + + align:start position:0% +mass right so if you have a fixed axis +of rotation and something going around + + align:start position:0% +of rotation and something going around + + + align:start position:0% +of rotation and something going around +it that's what this allows you to + + align:start position:0% +it that's what this allows you to + + + align:start position:0% +it that's what this allows you to +do okay that's one case so this is typ + + align:start position:0% +do okay that's one case so this is typ + + + align:start position:0% +do okay that's one case so this is typ +this we'll soon get the rigid bodies + + align:start position:0% +this we'll soon get the rigid bodies + + + align:start position:0% +this we'll soon get the rigid bodies +rigid bodies obey exactly the same + + align:start position:0% +rigid bodies obey exactly the same + + + align:start position:0% +rigid bodies obey exactly the same +formulas and you can have a rigid body + + align:start position:0% +formulas and you can have a rigid body + + + align:start position:0% +formulas and you can have a rigid body +now that it's not rotating about its + + align:start position:0% +now that it's not rotating about its + + + align:start position:0% +now that it's not rotating about its +Center but rotating maybe about its end + + align:start position:0% +Center but rotating maybe about its end + + + align:start position:0% +Center but rotating maybe about its end +like this that formul applies if the + + align:start position:0% +like this that formul applies if the + + + align:start position:0% +like this that formul applies if the +velocity of that axis about which it's + + align:start position:0% +velocity of that axis about which it's + + + align:start position:0% +velocity of that axis about which it's +rotating about which you're Computing + + align:start position:0% +rotating about which you're Computing + + + align:start position:0% +rotating about which you're Computing +this is not moving then you can just use + + align:start position:0% +this is not moving then you can just use + + + align:start position:0% +this is not moving then you can just use +you don't have to deal with that messy + + align:start position:0% +you don't have to deal with that messy + + + align:start position:0% +you don't have to deal with that messy +term so this is one case in which this + + align:start position:0% +term so this is one case in which this + + + align:start position:0% +term so this is one case in which this +term goes + + align:start position:0% +term goes + + + align:start position:0% +term goes +away the other case is if this velocity + + align:start position:0% +away the other case is if this velocity + + + align:start position:0% +away the other case is if this velocity +is parallel to the direction of the + + align:start position:0% +is parallel to the direction of the + + + align:start position:0% +is parallel to the direction of the +momentum and there's a really useful + + align:start position:0% +momentum and there's a really useful + + + align:start position:0% +momentum and there's a really useful +time that that happens + + align:start position:0% +time that that happens + + + align:start position:0% +time that that happens +so + + align:start position:0% +so + + + align:start position:0% +so +also this formula is true case + + align:start position:0% +also this formula is true case + + + align:start position:0% +also this formula is true case +two is when + + align:start position:0% +two is when + + + align:start position:0% +two is when +vao is parallel to PBO the direction + + align:start position:0% +vao is parallel to PBO the direction + + + align:start position:0% +vao is parallel to PBO the direction +they're going in the same direction now + + align:start position:0% +they're going in the same direction now + + + align:start position:0% +they're going in the same direction now +that happens when a is guaranteed to be + + align:start position:0% +that happens when a is guaranteed to be + + + align:start position:0% +that happens when a is guaranteed to be +true if a is at the center of + + align:start position:0% +true if a is at the center of + + + align:start position:0% +true if a is at the center of +mass because momentum is defined as the + + align:start position:0% +mass because momentum is defined as the + + + align:start position:0% +mass because momentum is defined as the +mass of the object object times the + + align:start position:0% +mass of the object object times the + + + align:start position:0% +mass of the object object times the +velocity of its Center of + + align:start position:0% +velocity of its Center of + + + align:start position:0% +velocity of its Center of +mass right even for rigid bodies + + align:start position:0% +mass right even for rigid bodies + + + align:start position:0% +mass right even for rigid bodies +so this is + + align:start position:0% + + + + align:start position:0% + +true + + align:start position:0% + + + + align:start position:0% + +when a is and I'll call it + + align:start position:0% +when a is and I'll call it + + + align:start position:0% +when a is and I'll call it +g at the center of + + align:start position:0% + + + + align:start position:0% + +mass so this gives + + align:start position:0% +mass so this gives + + + align:start position:0% +mass so this gives +us another really important + + align:start position:0% + + + + align:start position:0% + +generalization that we'll use that we + + align:start position:0% +generalization that we'll use that we + + + align:start position:0% +generalization that we'll use that we +make great use of in + + align:start position:0% + + + + align:start position:0% + +Dynamics and that says that the torque + + align:start position:0% +Dynamics and that says that the torque + + + align:start position:0% +Dynamics and that says that the torque +with respect to the center of + + align:start position:0% +with respect to the center of + + + align:start position:0% +with respect to the center of +mass is time rate of + + align:start position:0% +mass is time rate of + + + align:start position:0% +mass is time rate of +change of H with respect to + + align:start position:0% + + + + align:start position:0% + +G now I'm not going to go I did the + + align:start position:0% +G now I'm not going to go I did the + + + align:start position:0% +G now I'm not going to go I did the +proof this went through this little + + align:start position:0% +proof this went through this little + + + align:start position:0% +proof this went through this little +proof just for a particle but by summing + + align:start position:0% +proof just for a particle but by summing + + + align:start position:0% +proof just for a particle but by summing +a bunch of particles and kind of going + + align:start position:0% +a bunch of particles and kind of going + + + align:start position:0% +a bunch of particles and kind of going +through all the summations as we did to + + align:start position:0% +through all the summations as we did to + + + align:start position:0% +through all the summations as we did to +prove the center of mass formula you can + + align:start position:0% +prove the center of mass formula you can + + + align:start position:0% +prove the center of mass formula you can +show this allows you to very + + align:start position:0% +show this allows you to very + + + align:start position:0% +show this allows you to very +quickly show that this formulation is + + align:start position:0% +quickly show that this formulation is + + + align:start position:0% +quickly show that this formulation is +also true for rigid + + align:start position:0% + + + + align:start position:0% + +bodies so your way you say it for rigid + + align:start position:0% + + + + align:start position:0% + +bodies is that the sum of the torqus + + align:start position:0% +bodies is that the sum of the torqus + + + align:start position:0% +bodies is that the sum of the torqus +about with respect to some point for + + align:start position:0% +about with respect to some point for + + + align:start position:0% +about with respect to some point for +rigid + + align:start position:0% +rigid + + + align:start position:0% +rigid +body + + align:start position:0% +body + + + align:start position:0% +body +is H now Capital H H dot with respect to + + align:start position:0% +is H now Capital H H dot with respect to + + + align:start position:0% +is H now Capital H H dot with respect to +a plus the velocity of a with respect to + + align:start position:0% +a plus the velocity of a with respect to + + + align:start position:0% +a plus the velocity of a with respect to +O + + align:start position:0% +O + + + align:start position:0% +O +cross p and now I'm going to say G it's + + align:start position:0% +cross p and now I'm going to say G it's + + + align:start position:0% +cross p and now I'm going to say G it's +Center of Mass center of gravity with + + align:start position:0% +Center of Mass center of gravity with + + + align:start position:0% +Center of Mass center of gravity with +respect to + + align:start position:0% +respect to + + + align:start position:0% +respect to +O So the same statement for a rigid body + + align:start position:0% +O So the same statement for a rigid body + + + align:start position:0% +O So the same statement for a rigid body +is it's a torque with respect to some + + align:start position:0% +is it's a torque with respect to some + + + align:start position:0% +is it's a torque with respect to some +point a which can be moving now even + + align:start position:0% +point a which can be moving now even + + + align:start position:0% +point a which can be moving now even +accelerating is the time rate of change + + align:start position:0% +accelerating is the time rate of change + + + align:start position:0% +accelerating is the time rate of change +of the angular momentum with respect to + + align:start position:0% +of the angular momentum with respect to + + + align:start position:0% +of the angular momentum with respect to +a of that rigid body plus vao cross + + align:start position:0% +a of that rigid body plus vao cross + + + align:start position:0% +a of that rigid body plus vao cross +PG okay and again when would this te + + align:start position:0% +PG okay and again when would this te + + + align:start position:0% +PG okay and again when would this te +what would this messy second term go to + + align:start position:0% +what would this messy second term go to + + + align:start position:0% +what would this messy second term go to +zero when the velocity of a is zero + + align:start position:0% +zero when the velocity of a is zero + + + align:start position:0% +zero when the velocity of a is zero +fixed axis + + align:start position:0% +fixed axis + + + align:start position:0% +fixed axis +rotation or when this is parallel to + + align:start position:0% +rotation or when this is parallel to + + + align:start position:0% +rotation or when this is parallel to +that which is true for the center of + + align:start position:0% +that which is true for the center of + + + align:start position:0% +that which is true for the center of +mass always so the same same two special + + align:start position:0% +mass always so the same same two special + + + align:start position:0% +mass always so the same same two special +cases apply for rigid bodies + + align:start position:0% +cases apply for rigid bodies + + + align:start position:0% +cases apply for rigid bodies +when velocity of a with respect to O + + align:start position:0% +when velocity of a with respect to O + + + align:start position:0% +when velocity of a with respect to O +equals zero + + align:start position:0% +equals zero + + + align:start position:0% +equals zero +or when the velocity of a with respect + + align:start position:0% +or when the velocity of a with respect + + + align:start position:0% +or when the velocity of a with respect +to O is parallel to the uh + + align:start position:0% + + + + align:start position:0% + +p and this the the most important case + + align:start position:0% +p and this the the most important case + + + align:start position:0% +p and this the the most important case +of that is all always + + align:start position:0% +of that is all always + + + align:start position:0% +of that is all always +[Music] + + align:start position:0% + + + + align:start position:0% + +true that's always the case and in these + + align:start position:0% +true that's always the case and in these + + + align:start position:0% +true that's always the case and in these +when you can say this then the torque + + align:start position:0% +when you can say this then the torque + + + align:start position:0% +when you can say this then the torque +with respect to a is d + + align:start position:0% +with respect to a is d + + + align:start position:0% +with respect to a is d +h respect to a DT no second + + align:start position:0% + + + + align:start position:0% + +terms and it's those kinds of this + + align:start position:0% +terms and it's those kinds of this + + + align:start position:0% +terms and it's those kinds of this +you've applied generally in your physics + + align:start position:0% +you've applied generally in your physics + + + align:start position:0% +you've applied generally in your physics +like in 801 you've used formulas like + + align:start position:0% +like in 801 you've used formulas like + + + align:start position:0% +like in 801 you've used formulas like +this a + + align:start position:0% +this a + + + align:start position:0% +this a +lot done problems either with respect to + + align:start position:0% +lot done problems either with respect to + + + align:start position:0% +lot done problems either with respect to +the center of + + align:start position:0% +the center of + + + align:start position:0% +the center of +mass so objects run doing things like + + align:start position:0% +mass so objects run doing things like + + + align:start position:0% +mass so objects run doing things like +that you'll do the torque formulas with + + align:start position:0% +that you'll do the torque formulas with + + + align:start position:0% +that you'll do the torque formulas with +respect to the center of mass or + + align:start position:0% +respect to the center of mass or + + + align:start position:0% +respect to the center of mass or +when you have things that are pinned to + + align:start position:0% +when you have things that are pinned to + + + align:start position:0% +when you have things that are pinned to +points and rotate about fixed + + align:start position:0% +points and rotate about fixed + + + align:start position:0% +points and rotate about fixed +axes then you use the other formulation + + align:start position:0% +axes then you use the other formulation + + + align:start position:0% +axes then you use the other formulation +where it's with respect to a + + align:start position:0% +where it's with respect to a + + + align:start position:0% +where it's with respect to a +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +non-moving point so this is fixed axis + + align:start position:0% + + + + align:start position:0% + +rotation okay + + align:start position:0% + + + + align:start position:0% + +all right so that's kind of the dry + + align:start position:0% +all right so that's kind of the dry + + + align:start position:0% +all right so that's kind of the dry +derivation part of it I'm going to see + + align:start position:0% +derivation part of it I'm going to see + + + align:start position:0% +derivation part of it I'm going to see +if I can find an example + + align:start position:0% +if I can find an example + + + align:start position:0% +if I can find an example +[Applause] + + align:start position:0% + + + + align:start position:0% + +here okay this is quite a bit like a + + align:start position:0% +here okay this is quite a bit like a + + + align:start position:0% +here okay this is quite a bit like a +number of the homework problems + + align:start position:0% + + + + align:start position:0% + +so I've got a carnival + + align:start position:0% + + + + align:start position:0% + +ride got a bar + + align:start position:0% +ride got a bar + + + align:start position:0% +ride got a bar +and it's got a seat out + + align:start position:0% +and it's got a seat out + + + align:start position:0% +and it's got a seat out +here you're riding in it right so you're + + align:start position:0% +here you're riding in it right so you're + + + align:start position:0% +here you're riding in it right so you're +taking this + + align:start position:0% + + + + align:start position:0% + +ride it's + + align:start position:0% +ride it's + + + align:start position:0% +ride it's +rotating this is some fixed axis + + align:start position:0% + + + + align:start position:0% + +here and + + align:start position:0% +here and + + + align:start position:0% +here and +they you have a fixed coordinate system + + align:start position:0% +they you have a fixed coordinate system + + + align:start position:0% +they you have a fixed coordinate system +your + + align:start position:0% +your + + + align:start position:0% +your +o XYZ and then you'd probably have some + + align:start position:0% +o XYZ and then you'd probably have some + + + align:start position:0% +o XYZ and then you'd probably have some +rotating coordinate system with the + + align:start position:0% +rotating coordinate system with the + + + align:start position:0% +rotating coordinate system with the +point + + align:start position:0% + + + + align:start position:0% + +a fixed here at the axis of + + align:start position:0% +a fixed here at the axis of + + + align:start position:0% +a fixed here at the axis of +rotation + + align:start position:0% +rotation + + + align:start position:0% +rotation +and this is going the what's what's + + align:start position:0% +and this is going the what's what's + + + align:start position:0% +and this is going the what's what's +unusual about this ride not only can go + + align:start position:0% +unusual about this ride not only can go + + + align:start position:0% +unusual about this ride not only can go +around and round but the arm can go in + + align:start position:0% +around and round but the arm can go in + + + align:start position:0% +around and round but the arm can go in +and + + align:start position:0% + + + + align:start position:0% + +out so it might take a path inwards like + + align:start position:0% +out so it might take a path inwards like + + + align:start position:0% +out so it might take a path inwards like +if you pull the arm in as you're going + + align:start position:0% +if you pull the arm in as you're going + + + align:start position:0% +if you pull the arm in as you're going +around what are the forces that you feel + + align:start position:0% +around what are the forces that you feel + + + align:start position:0% +around what are the forces that you feel +in the ride + + align:start position:0% +in the ride + + + align:start position:0% +in the ride +okay so this is my point B out here it's + + align:start position:0% +okay so this is my point B out here it's + + + align:start position:0% +okay so this is my point B out here it's +where the person's at have some + + align:start position:0% +where the person's at have some + + + align:start position:0% +where the person's at have some +mass + + align:start position:0% +mass + + + align:start position:0% +mass +m and let's let for now first + + align:start position:0% + + + + align:start position:0% + +case Theta dot let that be constant + + align:start position:0% + + + + align:start position:0% + +a constant angular rate here here's + + align:start position:0% + + + + align:start position:0% + +Theta and r + + align:start position:0% + + + + align:start position:0% + +dot all + + align:start position:0% +dot all + + + align:start position:0% +dot all +right now you already know quite a bit + + align:start position:0% +right now you already know quite a bit + + + align:start position:0% +right now you already know quite a bit +about things like this what forces if + + align:start position:0% +about things like this what forces if + + + align:start position:0% +about things like this what forces if +you're riding in that + + align:start position:0% +you're riding in that + + + align:start position:0% +you're riding in that +bucket what forces do you think you + + align:start position:0% +bucket what forces do you think you + + + align:start position:0% +bucket what forces do you think you +would feel or I should say it in more + + align:start position:0% +would feel or I should say it in more + + + align:start position:0% +would feel or I should say it in more +carefully + + align:start position:0% +carefully + + + align:start position:0% +carefully +there will be accelerations that you + + align:start position:0% +there will be accelerations that you + + + align:start position:0% +there will be accelerations that you +feel in that bucket you'll feel like + + align:start position:0% +feel in that bucket you'll feel like + + + align:start position:0% +feel in that bucket you'll feel like +forces on you but what are the + + align:start position:0% +forces on you but what are the + + + align:start position:0% +forces on you but what are the +accelerations that you will feel you + + align:start position:0% +accelerations that you will feel you + + + align:start position:0% +accelerations that you will feel you +expect to be if you're riding in + + align:start position:0% + + + + align:start position:0% + +it I hear one here Cal acceleration so + + align:start position:0% +it I hear one here Cal acceleration so + + + align:start position:0% +it I hear one here Cal acceleration so +there'll be centripetal acceleration + + align:start position:0% +there'll be centripetal acceleration + + + align:start position:0% +there'll be centripetal acceleration +right everybody agree with that how + + align:start position:0% +right everybody agree with that how + + + align:start position:0% +right everybody agree with that how +anything else acceler it's going to be + + align:start position:0% +anything else acceler it's going to be + + + align:start position:0% +anything else acceler it's going to be +some coris because our DOT is not zero + + align:start position:0% +some coris because our DOT is not zero + + + align:start position:0% +some coris because our DOT is not zero +right it's changing in position and when + + align:start position:0% +right it's changing in position and when + + + align:start position:0% +right it's changing in position and when +the length of the arm of something + + align:start position:0% +the length of the arm of something + + + align:start position:0% +the length of the arm of something +rotating at constant speed changes what + + align:start position:0% +rotating at constant speed changes what + + + align:start position:0% +rotating at constant speed changes what +momentum + + align:start position:0% + + + + align:start position:0% + +changes angular for sure how about + + align:start position:0% +changes angular for sure how about + + + align:start position:0% +changes angular for sure how about +linear + + align:start position:0% +linear + + + align:start position:0% +linear +momentum yeah it's changing too because + + align:start position:0% +momentum yeah it's changing too because + + + align:start position:0% +momentum yeah it's changing too because +R cross p is angular momentum so both + + align:start position:0% +R cross p is angular momentum so both + + + align:start position:0% +R cross p is angular momentum so both +linear and angular momentum are changing + + align:start position:0% +linear and angular momentum are changing + + + align:start position:0% +linear and angular momentum are changing +as this radius gets longer or shorter + + align:start position:0% +as this radius gets longer or shorter + + + align:start position:0% +as this radius gets longer or shorter +and if the if that angular momentum + + align:start position:0% +and if the if that angular momentum + + + align:start position:0% +and if the if that angular momentum +changes it takes torque to drive it and + + align:start position:0% +changes it takes torque to drive it and + + + align:start position:0% +changes it takes torque to drive it and +so we ought to be able to use the + + align:start position:0% +so we ought to be able to use the + + + align:start position:0% +so we ought to be able to use the +formulas that we've just derived to + + align:start position:0% +formulas that we've just derived to + + + align:start position:0% +formulas that we've just derived to +calculate something about the torqus + + align:start position:0% +calculate something about the torqus + + + align:start position:0% +calculate something about the torqus +required to make this happen and the + + align:start position:0% +required to make this happen and the + + + align:start position:0% +required to make this happen and the +forces on the rider + + align:start position:0% + + + + align:start position:0% + +okay so we'll treat this one as a + + align:start position:0% +okay so we'll treat this one as a + + + align:start position:0% +okay so we'll treat this one as a +particle so H the angular momentum of + + align:start position:0% +particle so H the angular momentum of + + + align:start position:0% +particle so H the angular momentum of +that of the rider out here at B with + + align:start position:0% +that of the rider out here at B with + + + align:start position:0% +that of the rider out here at B with +respect to O + + align:start position:0% + + + + align:start position:0% + +it's going to be + + align:start position:0% +it's going to be + + + align:start position:0% +it's going to be +rvo + + align:start position:0% +rvo + + + align:start position:0% +rvo +cross + + align:start position:0% + + + + align:start position:0% + +p and in this problem I'll use polar + + align:start position:0% +p and in this problem I'll use polar + + + align:start position:0% +p and in this problem I'll use polar +coordinates pretty easy this is a planer + + align:start position:0% +coordinates pretty easy this is a planer + + + align:start position:0% +coordinates pretty easy this is a planer +motion problem it's confined to the XY + + align:start position:0% +motion problem it's confined to the XY + + + align:start position:0% +motion problem it's confined to the XY +plane and rotation in Z so polar + + align:start position:0% +plane and rotation in Z so polar + + + align:start position:0% +plane and rotation in Z so polar +coordinates are pretty convenient so + + align:start position:0% +coordinates are pretty convenient so + + + align:start position:0% +coordinates are pretty convenient so +this should look like radius r r + + align:start position:0% +this should look like radius r r + + + align:start position:0% +this should look like radius r r +Hat Cross and the the linear momentum of + + align:start position:0% +Hat Cross and the the linear momentum of + + + align:start position:0% +Hat Cross and the the linear momentum of +this is the + + align:start position:0% +this is the + + + align:start position:0% +this is the +masstimes r dot R hat that's the + + align:start position:0% +masstimes r dot R hat that's the + + + align:start position:0% +masstimes r dot R hat that's the +extension + + align:start position:0% +extension + + + align:start position:0% +extension +rate + + align:start position:0% +rate + + + align:start position:0% +rate +but it also has velocity in + + align:start position:0% +but it also has velocity in + + + align:start position:0% +but it also has velocity in +the Theta hat + + align:start position:0% +the Theta hat + + + align:start position:0% +the Theta hat +Direction R Theta hat so this is + + align:start position:0% +Direction R Theta hat so this is + + + align:start position:0% +Direction R Theta hat so this is +p with respect to o m v and this is the + + align:start position:0% +p with respect to o m v and this is the + + + align:start position:0% +p with respect to o m v and this is the +rad this is the r crossed into it now r + + align:start position:0% +rad this is the r crossed into it now r + + + align:start position:0% +rad this is the r crossed into it now r +r Hat Cross R hat gives you zero so you + + align:start position:0% +r Hat Cross R hat gives you zero so you + + + align:start position:0% +r Hat Cross R hat gives you zero so you +only get a single term out of this and + + align:start position:0% +only get a single term out of this and + + + align:start position:0% +only get a single term out of this and +you get an R cross R Hat Cross Theta hat + + align:start position:0% +you get an R cross R Hat Cross Theta hat + + + align:start position:0% +you get an R cross R Hat Cross Theta hat +positive K so this looks like plus + + align:start position:0% + + + + align:start position:0% + +m r + + align:start position:0% + + + + align:start position:0% + +2 Theta + + align:start position:0% +2 Theta + + + align:start position:0% +2 Theta +dot k + + align:start position:0% +dot k + + + align:start position:0% +dot k +hat that's my H Bo + + align:start position:0% + + + + align:start position:0% + +o now I would that's my first piece that + + align:start position:0% +o now I would that's my first piece that + + + align:start position:0% +o now I would that's my first piece that +I wanted to get that's the a part that's + + align:start position:0% +I wanted to get that's the a part that's + + + align:start position:0% +I wanted to get that's the a part that's +find the angular momentum so this is + + align:start position:0% +find the angular momentum so this is + + + align:start position:0% +find the angular momentum so this is +a B I want to know the + + align:start position:0% + + + + align:start position:0% + +torque + + align:start position:0% +torque + + + align:start position:0% +torque +okay well which formula can we + + align:start position:0% +okay well which formula can we + + + align:start position:0% +okay well which formula can we +use are we allowed to use do we have to + + align:start position:0% +use are we allowed to use do we have to + + + align:start position:0% +use are we allowed to use do we have to +account for that second + + align:start position:0% +account for that second + + + align:start position:0% +account for that second +term no why yeah the velocity of the + + align:start position:0% +term no why yeah the velocity of the + + + align:start position:0% +term no why yeah the velocity of the +point about which we're Computing the + + align:start position:0% +point about which we're Computing the + + + align:start position:0% +point about which we're Computing the +angular momentum and therefore the + + align:start position:0% +angular momentum and therefore the + + + align:start position:0% +angular momentum and therefore the +torque is not moving so you only have to + + align:start position:0% +torque is not moving so you only have to + + + align:start position:0% +torque is not moving so you only have to +deal with the first term so the + + align:start position:0% +deal with the first term so the + + + align:start position:0% +deal with the first term so the +torque required to move that particle at + + align:start position:0% +torque required to move that particle at + + + align:start position:0% +torque required to move that particle at +B with respect to O is just the time + + align:start position:0% +B with respect to O is just the time + + + align:start position:0% +B with respect to O is just the time +rate of change d by DT of h b with + + align:start position:0% +rate of change d by DT of h b with + + + align:start position:0% +rate of change d by DT of h b with +respect to O and that's d by DT + + align:start position:0% +respect to O and that's d by DT + + + align:start position:0% +respect to O and that's d by DT +of + + align:start position:0% +of + + + align:start position:0% +of +m r + + align:start position:0% +m r + + + align:start position:0% +m r +2 Theta + + align:start position:0% +2 Theta + + + align:start position:0% +2 Theta +dot k + + align:start position:0% +dot k + + + align:start position:0% +dot k +hat so what are the constants in this + + align:start position:0% +hat so what are the constants in this + + + align:start position:0% +hat so what are the constants in this +expression so we don't have to worry + + align:start position:0% +expression so we don't have to worry + + + align:start position:0% +expression so we don't have to worry +about their derivatives K hat change + + align:start position:0% +about their derivatives K hat change + + + align:start position:0% +about their derivatives K hat change +length no change direction no Theta dot + + align:start position:0% +length no change direction no Theta dot + + + align:start position:0% +length no change direction no Theta dot +does it change change in this + + align:start position:0% +does it change change in this + + + align:start position:0% +does it change change in this +problem no we fixed it we said it + + align:start position:0% +problem no we fixed it we said it + + + align:start position:0% +problem no we fixed it we said it +arbitrarily started off saying that + + align:start position:0% +arbitrarily started off saying that + + + align:start position:0% +arbitrarily started off saying that +we'll just let Theta dot be constant R + + align:start position:0% +we'll just let Theta dot be constant R + + + align:start position:0% +we'll just let Theta dot be constant R +though is changing so the time + + align:start position:0% +though is changing so the time + + + align:start position:0% +though is changing so the time +derivative of this particular one only + + align:start position:0% +derivative of this particular one only + + + align:start position:0% +derivative of this particular one only +we have to only have to deal with the r + + align:start position:0% +we have to only have to deal with the r + + + align:start position:0% +we have to only have to deal with the r +actually I'll I'll forget that for a + + align:start position:0% +actually I'll I'll forget that for a + + + align:start position:0% +actually I'll I'll forget that for a +second because I want to get both terms + + align:start position:0% +second because I want to get both terms + + + align:start position:0% +second because I want to get both terms +and then we'll let it be zero so this + + align:start position:0% +and then we'll let it be zero so this + + + align:start position:0% +and then we'll let it be zero so this +time derivative then when you work it + + align:start position:0% +time derivative then when you work it + + + align:start position:0% +time derivative then when you work it +out + + align:start position:0% + + + + align:start position:0% + +all + + align:start position:0% + + + + align:start position:0% + +right the derivative of the r term gives + + align:start position:0% +right the derivative of the r term gives + + + align:start position:0% +right the derivative of the r term gives +you 2 m r r do theta + + align:start position:0% +you 2 m r r do theta + + + align:start position:0% +you 2 m r r do theta +dot k hat + + align:start position:0% +dot k hat + + + align:start position:0% +dot k hat +and I'll just go ahead and forget for a + + align:start position:0% +and I'll just go ahead and forget for a + + + align:start position:0% +and I'll just go ahead and forget for a +minute that I said that's constant let's + + align:start position:0% +minute that I said that's constant let's + + + align:start position:0% +minute that I said that's constant let's +get the other term that might be + + align:start position:0% +get the other term that might be + + + align:start position:0% +get the other term that might be +there that term gives us + + align:start position:0% + + + + align:start position:0% + +uh m r 2 Theta double dot k + + align:start position:0% + + + + align:start position:0% + +hat this term comes from what we'll + + align:start position:0% +hat this term comes from what we'll + + + align:start position:0% +hat this term comes from what we'll +we'll find is the cholis one and this is + + align:start position:0% +we'll find is the cholis one and this is + + + align:start position:0% +we'll find is the cholis one and this is +from what we'd call the oil Arian + + align:start position:0% +from what we'd call the oil Arian + + + align:start position:0% +from what we'd call the oil Arian +acceleration this torque must the + + align:start position:0% +acceleration this torque must the + + + align:start position:0% +acceleration this torque must the +torque get this up a little + + align:start position:0% + + + + align:start position:0% + +higher we should be able to write as + + align:start position:0% +higher we should be able to write as + + + align:start position:0% +higher we should be able to write as +some R + + align:start position:0% +some R + + + align:start position:0% +some R +cross F right and so the r cross F terms + + align:start position:0% +cross F right and so the r cross F terms + + + align:start position:0% +cross F right and so the r cross F terms +this will + + align:start position:0% +this will + + + align:start position:0% +this will +be from the coris force and this would + + align:start position:0% +be from the coris force and this would + + + align:start position:0% +be from the coris force and this would +be from that or oian + + align:start position:0% +be from that or oian + + + align:start position:0% +be from that or oian +Force so this will look like r r hat + + align:start position:0% +Force so this will look like r r hat + + + align:start position:0% +Force so this will look like r r hat +crossed I'm just factoring this back out + + align:start position:0% +crossed I'm just factoring this back out + + + align:start position:0% +crossed I'm just factoring this back out +into its cross products RR Hat Cross 2 m + + align:start position:0% +into its cross products RR Hat Cross 2 m + + + align:start position:0% +into its cross products RR Hat Cross 2 m +r dot Theta dot in the Theta hat + + align:start position:0% +r dot Theta dot in the Theta hat + + + align:start position:0% +r dot Theta dot in the Theta hat +Direction plus + + align:start position:0% + + + + align:start position:0% + +r Theta double dot in the Theta hat + + align:start position:0% +r Theta double dot in the Theta hat + + + align:start position:0% +r Theta double dot in the Theta hat +Direction so there's two terms in this + + align:start position:0% +Direction so there's two terms in this + + + align:start position:0% +Direction so there's two terms in this +torque expression they come from R cross + + align:start position:0% +torque expression they come from R cross + + + align:start position:0% +torque expression they come from R cross +two Force + + align:start position:0% +two Force + + + align:start position:0% +two Force +terms the first Force term is what we + + align:start position:0% +terms the first Force term is what we + + + align:start position:0% +terms the first Force term is what we +know to be the cholis force and the + + align:start position:0% +know to be the cholis force and the + + + align:start position:0% +know to be the cholis force and the +second Force term I'm missing an M + + align:start position:0% + + + + align:start position:0% + +here RM Theta double do theta hat that's + + align:start position:0% +here RM Theta double do theta hat that's + + + align:start position:0% +here RM Theta double do theta hat that's +the force that takes to if the thing + + align:start position:0% +the force that takes to if the thing + + + align:start position:0% +the force that takes to if the thing +were're accelerating + + align:start position:0% +were're accelerating + + + align:start position:0% +were're accelerating +just to accelerate that ball Theta + + align:start position:0% +just to accelerate that ball Theta + + + align:start position:0% +just to accelerate that ball Theta +double dot takes that takes a force you + + align:start position:0% +double dot takes that takes a force you + + + align:start position:0% +double dot takes that takes a force you +do these cross products R cross Theta + + align:start position:0% +do these cross products R cross Theta + + + align:start position:0% +do these cross products R cross Theta +hat gives you k r cross Theta hat gives + + align:start position:0% +hat gives you k r cross Theta hat gives + + + align:start position:0% +hat gives you k r cross Theta hat gives +you K it all comes out in the right + + align:start position:0% +you K it all comes out in the right + + + align:start position:0% +you K it all comes out in the right +directions and now to do the problem we + + align:start position:0% +directions and now to do the problem we + + + align:start position:0% +directions and now to do the problem we +had we said oh yeah but this one's zero + + align:start position:0% +had we said oh yeah but this one's zero + + + align:start position:0% +had we said oh yeah but this one's zero +so we'll let this term go to + + align:start position:0% +so we'll let this term go to + + + align:start position:0% +so we'll let this term go to +zero we're left with a single term + + align:start position:0% + + + + align:start position:0% + +open + + align:start position:0% + + + + align:start position:0% + +and if we plugged in some numbers let's + + align:start position:0% +and if we plugged in some numbers let's + + + align:start position:0% +and if we plugged in some numbers let's +just see if how this works out and this + + align:start position:0% +just see if how this works out and this + + + align:start position:0% +just see if how this works out and this +we know it's just R cross the coris + + align:start position:0% + + + + align:start position:0% + +well let's let M you let M be 100 + + align:start position:0% +well let's let M you let M be 100 + + + align:start position:0% +well let's let M you let M be 100 +kilogram and R be 5 + + align:start position:0% +kilogram and R be 5 + + + align:start position:0% +kilogram and R be 5 +M and R + + align:start position:0% +M and R + + + align:start position:0% +M and R +dot + + align:start position:0% +dot + + + align:start position:0% +dot +0.4 m/ second all kind of perfectly + + align:start position:0% +0.4 m/ second all kind of perfectly + + + align:start position:0% +0.4 m/ second all kind of perfectly +reasonable + + align:start position:0% +reasonable + + + align:start position:0% +reasonable +dimensions and Theta + + align:start position:0% +dimensions and Theta + + + align:start position:0% +dimensions and Theta +dot equals 3 + + align:start position:0% +dot equals 3 + + + align:start position:0% +dot equals 3 +radians per second so 2 pi radians per + + align:start position:0% +radians per second so 2 pi radians per + + + align:start position:0% +radians per second so 2 pi radians per +second means it goes around once once a + + align:start position:0% +second means it goes around once once a + + + align:start position:0% +second means it goes around once once a +second right say a little less than half + + align:start position:0% +second right say a little less than half + + + align:start position:0% +second right say a little less than half +a REV per second + + align:start position:0% + + + + align:start position:0% + +yeah + + align:start position:0% +yeah + + + align:start position:0% +yeah +probably yeah good catch got to have an + + align:start position:0% +probably yeah good catch got to have an + + + align:start position:0% +probably yeah good catch got to have an +r in it because that R comes from here + + align:start position:0% +r in it because that R comes from here + + + align:start position:0% +r in it because that R comes from here +right so I had the coris force written + + align:start position:0% +right so I had the coris force written + + + align:start position:0% +right so I had the coris force written +down but not the r you have to multiply + + align:start position:0% +down but not the r you have to multiply + + + align:start position:0% +down but not the r you have to multiply +it by so now we got if you plug in all + + align:start position:0% +it by so now we got if you plug in all + + + align:start position:0% +it by so now we got if you plug in all +of these numbers let's see if it see if + + align:start position:0% +of these numbers let's see if it see if + + + align:start position:0% +of these numbers let's see if it see if +it's ride you could + + align:start position:0% + + + + align:start position:0% + +survive I actually computed the Coriolis + + align:start position:0% +survive I actually computed the Coriolis + + + align:start position:0% +survive I actually computed the Coriolis +Force first it's just a I think it's + + align:start position:0% +Force first it's just a I think it's + + + align:start position:0% +Force first it's just a I think it's +just interesting to get a physical + + align:start position:0% +just interesting to get a physical + + + align:start position:0% +just interesting to get a physical +feeling for how whether or not you can + + align:start position:0% +feeling for how whether or not you can + + + align:start position:0% +feeling for how whether or not you can +feel these forces so the Coriolis force + + align:start position:0% +feel these forces so the Coriolis force + + + align:start position:0% +feel these forces so the Coriolis force +is just everything but the r 2m r. Theta + + align:start position:0% +is just everything but the r 2m r. Theta + + + align:start position:0% +is just everything but the r 2m r. Theta +dot so if you calculate that you get + + align:start position:0% +dot so if you calculate that you get + + + align:start position:0% +dot so if you calculate that you get +240 Newtons + + align:start position:0% +240 Newtons + + + align:start position:0% +240 Newtons +and R times that the + + align:start position:0% + + + + align:start position:0% + +torque five times that about uh + + align:start position:0% + + + + align:start position:0% + +1,200 Newton + + align:start position:0% + + + + align:start position:0% + +M and the acceleration how do we gets + + align:start position:0% +M and the acceleration how do we gets + + + align:start position:0% +M and the acceleration how do we gets +acceleration well F core Corola force is + + align:start position:0% +acceleration well F core Corola force is + + + align:start position:0% +acceleration well F core Corola force is +some mass times an acceleration so we + + align:start position:0% +some mass times an acceleration so we + + + align:start position:0% +some mass times an acceleration so we +can solve from that 240 Newtons the ma + + align:start position:0% +can solve from that 240 Newtons the ma + + + align:start position:0% +can solve from that 240 Newtons the ma +the acceleration of the system + + align:start position:0% +the acceleration of the system + + + align:start position:0% +the acceleration of the system +acceleration of a b with respect to + + align:start position:0% + + + + align:start position:0% + +O 240 + + align:start position:0% +O 240 + + + align:start position:0% +O 240 +Newtons divided 100 + + align:start position:0% + + + + align:start position:0% + +kilogram + + align:start position:0% +kilogram + + + align:start position:0% +kilogram +2.4 m/ second s + + align:start position:0% +2.4 m/ second s + + + align:start position:0% +2.4 m/ second s +square and what's that in + + align:start position:0% + + + + align:start position:0% + +G's yeah about quarter of a + + align:start position:0% + + + + align:start position:0% + +g and again would you feel that so now + + align:start position:0% +g and again would you feel that so now + + + align:start position:0% +g and again would you feel that so now +you're riding so now you're riding in + + align:start position:0% +you're riding so now you're riding in + + + align:start position:0% +you're riding so now you're riding in +the bucket right let's say it's just + + align:start position:0% +the bucket right let's say it's just + + + align:start position:0% +the bucket right let's say it's just +spinning around the arm's not going in + + align:start position:0% +spinning around the arm's not going in + + + align:start position:0% +spinning around the arm's not going in +and out at all so you're riding in it + + align:start position:0% +and out at all so you're riding in it + + + align:start position:0% +and out at all so you're riding in it +what what force would you + + align:start position:0% +what what force would you + + + align:start position:0% +what what force would you +feel would you feel any forces pushing + + align:start position:0% +feel would you feel any forces pushing + + + align:start position:0% +feel would you feel any forces pushing +you into your + + align:start position:0% +you into your + + + align:start position:0% +you into your +seat constant speed r dot + + align:start position:0% + + + + align:start position:0% + +zero somebody out there would you feel + + align:start position:0% +zero somebody out there would you feel + + + align:start position:0% +zero somebody out there would you feel +any Force if you're going around and + + align:start position:0% +any Force if you're going around and + + + align:start position:0% +any Force if you're going around and +around in this thing sitting in the seat + + align:start position:0% +around in this thing sitting in the seat + + + align:start position:0% +around in this thing sitting in the seat +okay what's it come from centripetal + + align:start position:0% +okay what's it come from centripetal + + + align:start position:0% +okay what's it come from centripetal +acceleration right all right so and that + + align:start position:0% +acceleration right all right so and that + + + align:start position:0% +acceleration right all right so and that +is in what + + align:start position:0% +is in what + + + align:start position:0% +is in what +direction the acceleration is inward + + align:start position:0% +direction the acceleration is inward + + + align:start position:0% +direction the acceleration is inward +what would you actually feel + + align:start position:0% +what would you actually feel + + + align:start position:0% +what would you actually feel +you you'd feel if this but if this seat + + align:start position:0% +you you'd feel if this but if this seat + + + align:start position:0% +you you'd feel if this but if this seat +could swing out so you're facing in + + align:start position:0% +could swing out so you're facing in + + + align:start position:0% +could swing out so you're facing in +you'd feel like you're being thrown out + + align:start position:0% +you'd feel like you're being thrown out + + + align:start position:0% +you'd feel like you're being thrown out +in your seat + + align:start position:0% +in your seat + + + align:start position:0% +in your seat +right because you have to have a force + + align:start position:0% +right because you have to have a force + + + align:start position:0% +right because you have to have a force +on you to make that acceleration happen + + align:start position:0% +on you to make that acceleration happen + + + align:start position:0% +on you to make that acceleration happen +the acceleration is inward the force it + + align:start position:0% +the acceleration is inward the force it + + + align:start position:0% +the acceleration is inward the force it +better be pushing you inward so it's + + align:start position:0% +better be pushing you inward so it's + + + align:start position:0% +better be pushing you inward so it's +pushing on your back if you're looking + + align:start position:0% +pushing on your back if you're looking + + + align:start position:0% +pushing on your back if you're looking +in going around so that's the you know + + align:start position:0% +in going around so that's the you know + + + align:start position:0% +in going around so that's the you know +the + + align:start position:0% +the + + + align:start position:0% +the +uh forgotten the term for but you know + + align:start position:0% +uh forgotten the term for but you know + + + align:start position:0% +uh forgotten the term for but you know +they put the astronauts in a centrifuge + + align:start position:0% +they put the astronauts in a centrifuge + + + align:start position:0% +they put the astronauts in a centrifuge +right spin them around to see if they + + align:start position:0% +right spin them around to see if they + + + align:start position:0% +right spin them around to see if they +can take High G's okay that's the that's + + align:start position:0% +can take High G's okay that's the that's + + + align:start position:0% +can take High G's okay that's the that's +the G the inward high G acceleration due + + align:start position:0% +the G the inward high G acceleration due + + + align:start position:0% +the G the inward high G acceleration due +to the centripetal acceleration make you + + align:start position:0% +to the centripetal acceleration make you + + + align:start position:0% +to the centripetal acceleration make you +going in a circle but now not only are + + align:start position:0% +going in a circle but now not only are + + + align:start position:0% +going in a circle but now not only are +you going to feel that but now you start + + align:start position:0% +you going to feel that but now you start + + + align:start position:0% +you going to feel that but now you start +changing the length of the arm and if + + align:start position:0% +changing the length of the arm and if + + + align:start position:0% +changing the length of the arm and if +you change and if you change our DOT and + + align:start position:0% +you change and if you change our DOT and + + + align:start position:0% +you change and if you change our DOT and +make it positive so the arm is getting + + align:start position:0% +make it positive so the arm is getting + + + align:start position:0% +make it positive so the arm is getting +longer and we made this4 m/ second so + + align:start position:0% +longer and we made this4 m/ second so + + + align:start position:0% +longer and we made this4 m/ second so +it's moving out you know about like that + + align:start position:0% +it's moving out you know about like that + + + align:start position:0% +it's moving out you know about like that +it's not real fast but it's going to + + align:start position:0% +it's not real fast but it's going to + + + align:start position:0% +it's not real fast but it's going to +create a quarter of a g acceleration on + + align:start position:0% +create a quarter of a g acceleration on + + + align:start position:0% +create a quarter of a g acceleration on +you and and if R Dot's positive which + + align:start position:0% +you and and if R Dot's positive which + + + align:start position:0% +you and and if R Dot's positive which +direction is that + + align:start position:0% + + + + align:start position:0% + +acceleration I was careful we walked all + + align:start position:0% +acceleration I was careful we walked all + + + align:start position:0% +acceleration I was careful we walked all +the way through this the acceleration is + + align:start position:0% +the way through this the acceleration is + + + align:start position:0% +the way through this the acceleration is +positive but in what + + align:start position:0% +positive but in what + + + align:start position:0% +positive but in what +direction for + + align:start position:0% + + + + align:start position:0% + +coris Theta hat positive Theta hat so + + align:start position:0% +coris Theta hat positive Theta hat so + + + align:start position:0% +coris Theta hat positive Theta hat so +it's in direction of increasing Theta so + + align:start position:0% +it's in direction of increasing Theta so + + + align:start position:0% +it's in direction of increasing Theta so +this one is perpendicular to the arm + + align:start position:0% +this one is perpendicular to the arm + + + align:start position:0% +this one is perpendicular to the arm +right and this is this is the uh you + + align:start position:0% +right and this is this is the uh you + + + align:start position:0% +right and this is this is the uh you +know when my pingpong ball in here the + + align:start position:0% +know when my pingpong ball in here the + + + align:start position:0% +know when my pingpong ball in here the +force that actually causes it to speed + + align:start position:0% +force that actually causes it to speed + + + align:start position:0% +force that actually causes it to speed +up is partly cholis and partly orer and + + align:start position:0% +up is partly cholis and partly orer and + + + align:start position:0% +up is partly cholis and partly orer and +if I can make this go at constant speed + + align:start position:0% +if I can make this go at constant speed + + + align:start position:0% +if I can make this go at constant speed +the force that drives that the force + + align:start position:0% +the force that drives that the force + + + align:start position:0% +the force that drives that the force +that actually speeds that up is it going + + align:start position:0% +that actually speeds that up is it going + + + align:start position:0% +that actually speeds that up is it going +out is the coris force the normal one so + + align:start position:0% +out is the coris force the normal one so + + + align:start position:0% +out is the coris force the normal one so +if you were on this ride you'd be + + align:start position:0% +if you were on this ride you'd be + + + align:start position:0% +if you were on this ride you'd be +feeling about a quarter of a g + + align:start position:0% +feeling about a quarter of a g + + + align:start position:0% +feeling about a quarter of a g +perpendicular to the arm you'd be + + align:start position:0% +perpendicular to the arm you'd be + + + align:start position:0% +perpendicular to the arm you'd be +feeling another Force inward that's the + + align:start position:0% +feeling another Force inward that's the + + + align:start position:0% +feeling another Force inward that's the +Cent due to caused by the centripetal + + align:start position:0% +Cent due to caused by the centripetal + + + align:start position:0% +Cent due to caused by the centripetal +acceleration so you'd be feeling both of + + align:start position:0% +acceleration so you'd be feeling both of + + + align:start position:0% +acceleration so you'd be feeling both of +them how big is the centripetal + + align:start position:0% +them how big is the centripetal + + + align:start position:0% +them how big is the centripetal +acceleration + + align:start position:0% +acceleration + + + align:start position:0% +acceleration +sort of like + + align:start position:0% + + + + align:start position:0% + +uh R Omega squ right yeah R is 5 Omega + + align:start position:0% +uh R Omega squ right yeah R is 5 Omega + + + align:start position:0% +uh R Omega squ right yeah R is 5 Omega +is 3 3^ 2 is 9 * + + align:start position:0% + + + + align:start position:0% + +5 9 * 5 + + align:start position:0% +5 9 * 5 + + + align:start position:0% +5 9 * 5 +45 divided by 10 4 and a half + + align:start position:0% +45 divided by 10 4 and a half + + + align:start position:0% +45 divided by 10 4 and a half +gez you wouldn't notice the cor you + + align:start position:0% +gez you wouldn't notice the cor you + + + align:start position:0% +gez you wouldn't notice the cor you +wouldn't notice the cholis very much + + align:start position:0% +wouldn't notice the cholis very much + + + align:start position:0% +wouldn't notice the cholis very much +it'd be kind of this' be kind of a tough + + align:start position:0% +it'd be kind of this' be kind of a tough + + + align:start position:0% +it'd be kind of this' be kind of a tough +tough ride on the uh on that side of + + align:start position:0% +tough ride on the uh on that side of + + + align:start position:0% +tough ride on the uh on that side of +things Okay so we've now we've done that + + align:start position:0% +things Okay so we've now we've done that + + + align:start position:0% +things Okay so we've now we've done that +uh you've seen a simple application + + align:start position:0% +uh you've seen a simple application + + + align:start position:0% +uh you've seen a simple application +pretty straightforward application of + + align:start position:0% +pretty straightforward application of + + + align:start position:0% +pretty straightforward application of +using time derivative of angular + + align:start position:0% +using time derivative of angular + + + align:start position:0% +using time derivative of angular +momentum to calculate + + align:start position:0% +momentum to calculate + + + align:start position:0% +momentum to calculate +torqus so homework again there's a + + align:start position:0% +torqus so homework again there's a + + + align:start position:0% +torqus so homework again there's a +couple problems you know very similar to + + align:start position:0% +couple problems you know very similar to + + + align:start position:0% +couple problems you know very similar to +the one I just did things going around + + align:start position:0% +the one I just did things going around + + + align:start position:0% +the one I just did things going around +Circus rides that kind of stuff so + + align:start position:0% +Circus rides that kind of stuff so + + + align:start position:0% +Circus rides that kind of stuff so +so have a good weekend see you on + + align:start position:0% +so have a good weekend see you on + + + align:start position:0% +so have a good weekend see you on +Tuesday \ No newline at end of file diff --git a/NS0pxSF0Kmo.txt b/NS0pxSF0Kmo.txt new file mode 100644 index 0000000000000000000000000000000000000000..238ffbd7c7c697185813f3826f70b293d02c8502 --- /dev/null +++ b/NS0pxSF0Kmo.txt @@ -0,0 +1,827 @@ +align:start position:0% + +so now let's talk about how we go from I + + align:start position:0% +so now let's talk about how we go from I + + + align:start position:0% +so now let's talk about how we go from I +have a passion to a technology or an + + align:start position:0% +have a passion to a technology or an + + + align:start position:0% +have a passion to a technology or an +idea what are the factors even within a + + align:start position:0% +idea what are the factors even within a + + + align:start position:0% +idea what are the factors even within a +technology or an idea that would you + + align:start position:0% +technology or an idea that would you + + + align:start position:0% +technology or an idea that would you +would decide with your team now we + + align:start position:0% +would decide with your team now we + + + align:start position:0% +would decide with your team now we +talked about joining with the team um + + align:start position:0% +talked about joining with the team um + + + align:start position:0% +talked about joining with the team um +what are those things that you would + + align:start position:0% +what are those things that you would + + + align:start position:0% +what are those things that you would +make a factors to decide first of all + + align:start position:0% +make a factors to decide first of all + + + align:start position:0% +make a factors to decide first of all +you would start with knowledge you want + + align:start position:0% +you would start with knowledge you want + + + align:start position:0% +you would start with knowledge you want +to be working in a + + align:start position:0% +to be working in a + + + align:start position:0% +to be working in a +in a area or technology or Marketplace + + align:start position:0% +in a area or technology or Marketplace + + + align:start position:0% +in a area or technology or Marketplace +that you understand that you have a + + align:start position:0% +that you understand that you have a + + + align:start position:0% +that you understand that you have a +knowledge about um but that's necessary + + align:start position:0% +knowledge about um but that's necessary + + + align:start position:0% +knowledge about um but that's necessary +but not sufficient the next thing is + + align:start position:0% +but not sufficient the next thing is + + + align:start position:0% +but not sufficient the next thing is +that you have to have a + + align:start position:0% +that you have to have a + + + align:start position:0% +that you have to have a +Capa ability there something that that's + + align:start position:0% +Capa ability there something that that's + + + align:start position:0% +Capa ability there something that that's +special to you you might be good at + + align:start position:0% +special to you you might be good at + + + align:start position:0% +special to you you might be good at +Material Science and that would allow + + align:start position:0% +Material Science and that would allow + + + align:start position:0% +Material Science and that would allow +you to do energy storage you might not + + align:start position:0% +you to do energy storage you might not + + + align:start position:0% +you to do energy storage you might not +have that expertise but you might have + + align:start position:0% +have that expertise but you might have + + + align:start position:0% +have that expertise but you might have +um an understanding after having worked + + align:start position:0% +um an understanding after having worked + + + align:start position:0% +um an understanding after having worked +rathon for 10 years of what the + + align:start position:0% +rathon for 10 years of what the + + + align:start position:0% +rathon for 10 years of what the +Aerospace industry is about and the + + align:start position:0% +Aerospace industry is about and the + + + align:start position:0% +Aerospace industry is about and the +issues that they face so that's a + + align:start position:0% +issues that they face so that's a + + + align:start position:0% +issues that they face so that's a +special capability that you can build up + + align:start position:0% +special capability that you can build up + + + align:start position:0% +special capability that you can build up +the third thing + + align:start position:0% + + + + align:start position:0% + +is would + + align:start position:0% +is would + + + align:start position:0% +is would +be + + align:start position:0% +be + + + align:start position:0% +be +connections connections you say well + + align:start position:0% +connections connections you say well + + + align:start position:0% +connections connections you say well +that's something that's easy no that + + align:start position:0% +that's something that's easy no that + + + align:start position:0% +that's something that's easy no that +actually is an asset that you and your + + align:start position:0% +actually is an asset that you and your + + + align:start position:0% +actually is an asset that you and your +team would have do you know the proper + + align:start position:0% +team would have do you know the proper + + + align:start position:0% +team would have do you know the proper +people in this industry do you know the + + align:start position:0% +people in this industry do you know the + + + align:start position:0% +people in this industry do you know the +the people who really understand energy + + align:start position:0% +the people who really understand energy + + + align:start position:0% +the people who really understand energy +storage or whatever the other technology + + align:start position:0% +storage or whatever the other technology + + + align:start position:0% +storage or whatever the other technology +is that you might be working on having + + align:start position:0% +is that you might be working on having + + + align:start position:0% +is that you might be working on having +the right connections is a valuable + + align:start position:0% +the right connections is a valuable + + + align:start position:0% +the right connections is a valuable +asset that should not be + + align:start position:0% +asset that should not be + + + align:start position:0% +asset that should not be +overlooked the next one number four + + align:start position:0% +overlooked the next one number four + + + align:start position:0% +overlooked the next one number four +would be an Financial assets you might + + align:start position:0% +would be an Financial assets you might + + + align:start position:0% +would be an Financial assets you might +have very few Financial assets or you + + align:start position:0% +have very few Financial assets or you + + + align:start position:0% +have very few Financial assets or you +might have a lot of financial assets + + align:start position:0% +might have a lot of financial assets + + + align:start position:0% +might have a lot of financial assets +understanding the level of financial + + align:start position:0% +understanding the level of financial + + + align:start position:0% +understanding the level of financial +assets you have be it very small medium + + align:start position:0% +assets you have be it very small medium + + + align:start position:0% +assets you have be it very small medium +or large will dictate what markets are + + align:start position:0% +or large will dictate what markets are + + + align:start position:0% +or large will dictate what markets are +good for you if you if you don't have a + + align:start position:0% +good for you if you if you don't have a + + + align:start position:0% +good for you if you if you don't have a +lot of assets it's very hard to play in + + align:start position:0% +lot of assets it's very hard to play in + + + align:start position:0% +lot of assets it's very hard to play in +Industries where such as clean energy + + align:start position:0% +Industries where such as clean energy + + + align:start position:0% +Industries where such as clean energy +where the price of Poker is very high + + align:start position:0% +where the price of Poker is very high + + + align:start position:0% +where the price of Poker is very high +where the price of Entry is very high so + + align:start position:0% +where the price of Entry is very high so + + + align:start position:0% +where the price of Entry is very high so +the next one is name recognition + + align:start position:0% +the next one is name recognition + + + align:start position:0% +the next one is name recognition +so when you when you look at these + + align:start position:0% +so when you when you look at these + + + align:start position:0% +so when you when you look at these +um markets you might know the market you + + align:start position:0% +um markets you might know the market you + + + align:start position:0% +um markets you might know the market you +might have capability in that market you + + align:start position:0% +might have capability in that market you + + + align:start position:0% +might have capability in that market you +might know the right people you might + + align:start position:0% +might know the right people you might + + + align:start position:0% +might know the right people you might +have the financial but did the people in + + align:start position:0% +have the financial but did the people in + + + align:start position:0% +have the financial but did the people in +that market know someone on your team + + align:start position:0% +that market know someone on your team + + + align:start position:0% +that market know someone on your team +will they return the call when you when + + align:start position:0% +will they return the call when you when + + + align:start position:0% +will they return the call when you when +you contact them um inherent in this is + + align:start position:0% +you contact them um inherent in this is + + + align:start position:0% +you contact them um inherent in this is +credibility that you would have as well + + align:start position:0% +credibility that you would have as well + + + align:start position:0% +credibility that you would have as well +and that credibility would come from + + align:start position:0% +and that credibility would come from + + + align:start position:0% +and that credibility would come from +past work + + align:start position:0% + + + + align:start position:0% + +experience now past work + + align:start position:0% +experience now past work + + + align:start position:0% +experience now past work +experience could contribute as well to + + align:start position:0% +experience could contribute as well to + + + align:start position:0% +experience could contribute as well to +capability and knowledge and connections + + align:start position:0% +capability and knowledge and connections + + + align:start position:0% +capability and knowledge and connections +but I bring that out because there's + + align:start position:0% +but I bring that out because there's + + + align:start position:0% +but I bring that out because there's +other things that would come from past + + align:start position:0% +other things that would come from past + + + align:start position:0% +other things that would come from past +work work experience that I might not + + align:start position:0% +work work experience that I might not + + + align:start position:0% +work work experience that I might not +have included in here um number + + align:start position:0% +have included in here um number + + + align:start position:0% +have included in here um number +seven would be a + + align:start position:0% +seven would be a + + + align:start position:0% +seven would be a +passion what you're going to be doing + + align:start position:0% +passion what you're going to be doing + + + align:start position:0% +passion what you're going to be doing +when you choose it you better love + + align:start position:0% +when you choose it you better love + + + align:start position:0% +when you choose it you better love +because you're if you can't see yourself + + align:start position:0% +because you're if you can't see yourself + + + align:start position:0% +because you're if you can't see yourself +doing this for the next six years you're + + align:start position:0% +doing this for the next six years you're + + + align:start position:0% +doing this for the next six years you're +very likely not going to be a successful + + align:start position:0% +very likely not going to be a successful + + + align:start position:0% +very likely not going to be a successful +entrepreneur you have got to have a lot + + align:start position:0% +entrepreneur you have got to have a lot + + + align:start position:0% +entrepreneur you have got to have a lot +of passion for what you're doing so I + + align:start position:0% +of passion for what you're doing so I + + + align:start position:0% +of passion for what you're doing so I +said there were eight eight items that + + align:start position:0% +said there were eight eight items that + + + align:start position:0% +said there were eight eight items that +that we would consider knowledge + + align:start position:0% +that we would consider knowledge + + + align:start position:0% +that we would consider knowledge +capability connections Financial assets + + align:start position:0% +capability connections Financial assets + + + align:start position:0% +capability connections Financial assets +name recognition past work experience + + align:start position:0% +name recognition past work experience + + + align:start position:0% +name recognition past work experience +which might contribute other ones and + + align:start position:0% +which might contribute other ones and + + + align:start position:0% +which might contribute other ones and +passion we need to have passion the last + + align:start position:0% +passion we need to have passion the last + + + align:start position:0% +passion we need to have passion the last +thing is even if you have all those + + align:start position:0% +thing is even if you have all those + + + align:start position:0% +thing is even if you have all those +things the last one you need is + + align:start position:0% +things the last one you need is + + + align:start position:0% +things the last one you need is +commitment um when we look at who will + + align:start position:0% +commitment um when we look at who will + + + align:start position:0% +commitment um when we look at who will +succeed and who will not succeed who we + + align:start position:0% +succeed and who will not succeed who we + + + align:start position:0% +succeed and who will not succeed who we +take in our founder skills accelerator + + align:start position:0% +take in our founder skills accelerator + + + align:start position:0% +take in our founder skills accelerator +who we take into our more select classes + + align:start position:0% +who we take into our more select classes + + + align:start position:0% +who we take into our more select classes +one of the number one things we look at + + align:start position:0% +one of the number one things we look at + + + align:start position:0% +one of the number one things we look at +is commitment cuz the person who is + + align:start position:0% +is commitment cuz the person who is + + + align:start position:0% +is commitment cuz the person who is +committed to this they're burning the + + align:start position:0% +committed to this they're burning the + + + align:start position:0% +committed to this they're burning the +boats this is what they're going to do + + align:start position:0% +boats this is what they're going to do + + + align:start position:0% +boats this is what they're going to do +is going to be more successful other + + align:start position:0% +is going to be more successful other + + + align:start position:0% +is going to be more successful other +people might start off with better + + align:start position:0% +people might start off with better + + + align:start position:0% +people might start off with better +technology but in the end the person who + + align:start position:0% +technology but in the end the person who + + + align:start position:0% +technology but in the end the person who +has the commitment is going to pass pass + + align:start position:0% +has the commitment is going to pass pass + + + align:start position:0% +has the commitment is going to pass pass +them all so those are the things that we + + align:start position:0% +them all so those are the things that we + + + align:start position:0% +them all so those are the things that we +look at as you go from a passion to a + + align:start position:0% +look at as you go from a passion to a + + + align:start position:0% +look at as you go from a passion to a +technology or an idea and then within + + align:start position:0% +technology or an idea and then within + + + align:start position:0% +technology or an idea and then within +the technology or idea which one are you + + align:start position:0% +the technology or idea which one are you + + + align:start position:0% +the technology or idea which one are you +going to choose these are some of the + + align:start position:0% +going to choose these are some of the + + + align:start position:0% +going to choose these are some of the +important factors that you must think + + align:start position:0% +important factors that you must think + + + align:start position:0% +important factors that you must think +about \ No newline at end of file diff --git a/OAI8C20E7R4.txt b/OAI8C20E7R4.txt new file mode 100644 index 0000000000000000000000000000000000000000..08d347fda95ee60a13802b1ef5b4d7dd499ac6d7 --- /dev/null +++ b/OAI8C20E7R4.txt @@ -0,0 +1,11195 @@ +align:start position:0% + +Okay everyone. Um so so today uh we're + + align:start position:0% +Okay everyone. Um so so today uh we're + + + align:start position:0% +Okay everyone. Um so so today uh we're +going to learn some of the fundamental + + align:start position:0% +going to learn some of the fundamental + + + align:start position:0% +going to learn some of the fundamental +estimates of projection theory for balls + + align:start position:0% +estimates of projection theory for balls + + + align:start position:0% +estimates of projection theory for balls +in the plane for the setting of real + + align:start position:0% +in the plane for the setting of real + + + align:start position:0% +in the plane for the setting of real +analysis. Um there are kind of two goals + + align:start position:0% +analysis. Um there are kind of two goals + + + align:start position:0% +analysis. Um there are kind of two goals +of the class. The first goal is to adapt + + align:start position:0% +of the class. The first goal is to adapt + + + align:start position:0% +of the class. The first goal is to adapt +the techniques that we learned last time + + align:start position:0% +the techniques that we learned last time + + + align:start position:0% +the techniques that we learned last time +in finite fields. So the double counting + + align:start position:0% +in finite fields. So the double counting + + + align:start position:0% +in finite fields. So the double counting +technique and the forier technique to + + align:start position:0% +technique and the forier technique to + + + align:start position:0% +technique and the forier technique to +uklitian space. Um and the second goal + + align:start position:0% +uklitian space. Um and the second goal + + + align:start position:0% +uklitian space. Um and the second goal +is to start to explore. So there's a + + align:start position:0% +is to start to explore. So there's a + + + align:start position:0% +is to start to explore. So there's a +difference between uklidian space and + + align:start position:0% +difference between uklidian space and + + + align:start position:0% +difference between uklidian space and +finite fields is that in uklidian space + + align:start position:0% +finite fields is that in uklidian space + + + align:start position:0% +finite fields is that in uklidian space +we have to pay attention to how the how + + align:start position:0% +we have to pay attention to how the how + + + align:start position:0% +we have to pay attention to how the how +our sets are clustered. And so the + + align:start position:0% +our sets are clustered. And so the + + + align:start position:0% +our sets are clustered. And so the +second goal of the class is to start to + + align:start position:0% +second goal of the class is to start to + + + align:start position:0% +second goal of the class is to start to +explore uh clustering can cl information + + align:start position:0% +explore uh clustering can cl information + + + align:start position:0% +explore uh clustering can cl information +about how the sets are clustered and and + + align:start position:0% +about how the sets are clustered and and + + + align:start position:0% +about how the sets are clustered and and +how that comes into the store. + + align:start position:0% +how that comes into the store. + + + align:start position:0% +how that comes into the store. +Okay, + + align:start position:0% + + + + align:start position:0% + +so here's our setup. + + align:start position:0% + + + + align:start position:0% + +We'll have X will be a set + + align:start position:0% +We'll have X will be a set + + + align:start position:0% +We'll have X will be a set +of disjoint + + align:start position:0% + + + + align:start position:0% + +unit balls + + align:start position:0% +unit balls + + + align:start position:0% +unit balls +in um in the ball of radius R in the + + align:start position:0% +in um in the ball of radius R in the + + + align:start position:0% +in um in the ball of radius R in the +plane. + + align:start position:0% +plane. + + + align:start position:0% +plane. +Okay, so that's our set of points, set + + align:start position:0% +Okay, so that's our set of points, set + + + align:start position:0% +Okay, so that's our set of points, set +of balls. And then we're going to have a + + align:start position:0% +of balls. And then we're going to have a + + + align:start position:0% +of balls. And then we're going to have a +set of directions called D. So D is a + + align:start position:0% +set of directions called D. So D is a + + + align:start position:0% +set of directions called D. So D is a +finite subset of S1. It's 1 / R + + align:start position:0% +finite subset of S1. It's 1 / R + + + align:start position:0% +finite subset of S1. It's 1 / R +separated. So the distance between any + + align:start position:0% +separated. So the distance between any + + + align:start position:0% +separated. So the distance between any +two points of D is at least one / R + + align:start position:0% +two points of D is at least one / R + + + align:start position:0% +two points of D is at least one / R +D. Um and then S which depends on X and + + align:start position:0% +D. Um and then S which depends on X and + + + align:start position:0% +D. Um and then S which depends on X and +D + + align:start position:0% +D + + + align:start position:0% +D +is the maximum size of the projection. + + align:start position:0% +is the maximum size of the projection. + + + align:start position:0% +is the maximum size of the projection. +So I look at all the ang all the + + align:start position:0% +So I look at all the ang all the + + + align:start position:0% +So I look at all the ang all the +directions in D and I project the set X + + align:start position:0% +directions in D and I project the set X + + + align:start position:0% +directions in D and I project the set X +in that direction and I take its measure + + align:start position:0% +in that direction and I take its measure + + + align:start position:0% +in that direction and I take its measure +and the maximum of that is called S. + + align:start position:0% +and the maximum of that is called S. + + + align:start position:0% +and the maximum of that is called S. +Okay. So projection theory we try to + + align:start position:0% +Okay. So projection theory we try to + + + align:start position:0% +Okay. So projection theory we try to +understand how these things are related + + align:start position:0% +understand how these things are related + + + align:start position:0% +understand how these things are related +to each other and in this uklidian + + align:start position:0% +to each other and in this uklidian + + + align:start position:0% +to each other and in this uklidian +setting we also need to care about how + + align:start position:0% +setting we also need to care about how + + + align:start position:0% +setting we also need to care about how +this set X and how the set D are + + align:start position:0% +this set X and how the set D are + + + align:start position:0% +this set X and how the set D are +clustered. + + align:start position:0% +clustered. + + + align:start position:0% +clustered. +So that's measured by I guess call them + + align:start position:0% +So that's measured by I guess call them + + + align:start position:0% +So that's measured by I guess call them +clustering functions. So n subx of + + align:start position:0% +clustering functions. So n subx of + + + align:start position:0% +clustering functions. So n subx of +little r is the measures the most amount + + align:start position:0% +little r is the measures the most amount + + + align:start position:0% +little r is the measures the most amount +of x in any ball of radius little r. So + + align:start position:0% +of x in any ball of radius little r. So + + + align:start position:0% +of x in any ball of radius little r. So +this is the maximum + + align:start position:0% +this is the maximum + + + align:start position:0% +this is the maximum +over c in r2 or um of the size of x + + align:start position:0% +over c in r2 or um of the size of x + + + align:start position:0% +over c in r2 or um of the size of x +intersected with the ball around c of + + align:start position:0% +intersected with the ball around c of + + + align:start position:0% +intersected with the ball around c of +radius r. + + align:start position:0% +radius r. + + + align:start position:0% +radius r. +So this measures how x is clustered and + + align:start position:0% +So this measures how x is clustered and + + + align:start position:0% +So this measures how x is clustered and +we're also going to measure how d is + + align:start position:0% +we're also going to measure how d is + + + align:start position:0% +we're also going to measure how d is +cluster clustered. So n subd of row + + align:start position:0% +cluster clustered. So n subd of row + + + align:start position:0% +cluster clustered. So n subd of row +is the maximum + + align:start position:0% +is the maximum + + + align:start position:0% +is the maximum +over any uh so sigma in s1 and arc + + align:start position:0% +over any uh so sigma in s1 and arc + + + align:start position:0% +over any uh so sigma in s1 and arc +of length row of d intersect zip. + + align:start position:0% + + + + align:start position:0% + +Okay. + + align:start position:0% + + + + align:start position:0% + +Okay. So our big goal is in terms of + + align:start position:0% +Okay. So our big goal is in terms of + + + align:start position:0% +Okay. So our big goal is in terms of +this information and and how big d is + + align:start position:0% +this information and and how big d is + + + align:start position:0% +this information and and how big d is +and how big x is. What can we say about + + align:start position:0% +and how big x is. What can we say about + + + align:start position:0% +and how big x is. What can we say about +S? + + align:start position:0% +S? + + + align:start position:0% +S? +Okay. + + align:start position:0% + + + + align:start position:0% + +Okay. So, we're first going to do the + + align:start position:0% +Okay. So, we're first going to do the + + + align:start position:0% +Okay. So, we're first going to do the +double counting approach. + + align:start position:0% + + + + align:start position:0% + +And the argument is in in spirit the + + align:start position:0% +And the argument is in in spirit the + + + align:start position:0% +And the argument is in in spirit the +same as last time. But we'll see that + + align:start position:0% +same as last time. But we'll see that + + + align:start position:0% +same as last time. But we'll see that +when we try to do the double counting + + align:start position:0% +when we try to do the double counting + + + align:start position:0% +when we try to do the double counting +that we did last time that the n subx + + align:start position:0% +that we did last time that the n subx + + + align:start position:0% +that we did last time that the n subx +function and the n subd function will + + align:start position:0% +function and the n subd function will + + + align:start position:0% +function and the n subd function will +come into the store and it leads to the + + align:start position:0% +come into the store and it leads to the + + + align:start position:0% +come into the store and it leads to the +following bound. So theorem one I'll + + align:start position:0% +following bound. So theorem one I'll + + + align:start position:0% +following bound. So theorem one I'll +call it theorem 1 r r r r r r r r r r r + + align:start position:0% +call it theorem 1 r r r r r r r r r r r + + + align:start position:0% +call it theorem 1 r r r r r r r r r r r +r r r r r r r r r r for the real case. + + align:start position:0% +r r r r r r r r r r for the real case. + + + align:start position:0% +r r r r r r r r r r for the real case. +Uh whereas last time we had something + + align:start position:0% +Uh whereas last time we had something + + + align:start position:0% +Uh whereas last time we had something +called theorem one which when I do it + + align:start position:0% +called theorem one which when I do it + + + align:start position:0% +called theorem one which when I do it +again it'll be theorem 1 f for the + + align:start position:0% +again it'll be theorem 1 f for the + + + align:start position:0% +again it'll be theorem 1 f for the +finite field case and eventually we'll + + align:start position:0% +finite field case and eventually we'll + + + align:start position:0% +finite field case and eventually we'll +compare them. + + align:start position:0% +compare them. + + + align:start position:0% +compare them. +Okay. So if we have this setup + + align:start position:0% + + + + align:start position:0% + +then + + align:start position:0% +then + + + align:start position:0% +then +the number of directions is bounded by + + align:start position:0% +the number of directions is bounded by + + + align:start position:0% +the number of directions is bounded by +let's see + + align:start position:0% + + + + align:start position:0% + +okay so you'll notice that this is not a + + align:start position:0% +okay so you'll notice that this is not a + + + align:start position:0% +okay so you'll notice that this is not a +formula that I have memorized + + align:start position:0% +formula that I have memorized + + + align:start position:0% +formula that I have memorized +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +s overx times the sum over different + + align:start position:0% +s overx times the sum over different + + + align:start position:0% +s overx times the sum over different +scales else. + + align:start position:0% + + + + align:start position:0% + +Cool. Okay. So, it's a sum over + + align:start position:0% +Cool. Okay. So, it's a sum over + + + align:start position:0% +Cool. Okay. So, it's a sum over +different scales and we often in this + + align:start position:0% +different scales and we often in this + + + align:start position:0% +different scales and we often in this +class will sum over a diadic sequence of + + align:start position:0% +class will sum over a diadic sequence of + + + align:start position:0% +class will sum over a diadic sequence of +scales, powers of two or whatever. Um uh + + align:start position:0% +scales, powers of two or whatever. Um uh + + + align:start position:0% +scales, powers of two or whatever. Um uh +okay and um and the so the formula + + align:start position:0% +okay and um and the so the formula + + + align:start position:0% +okay and um and the so the formula +doesn't yet look that similar but the + + align:start position:0% +doesn't yet look that similar but the + + + align:start position:0% +doesn't yet look that similar but the +the idea is the same as last time and + + align:start position:0% +the idea is the same as last time and + + + align:start position:0% +the idea is the same as last time and +then eventually we'll compare the + + align:start position:0% +then eventually we'll compare the + + + align:start position:0% +then eventually we'll compare the +formulas and see that under certain + + align:start position:0% +formulas and see that under certain + + + align:start position:0% +formulas and see that under certain +assumptions on this it's actually very + + align:start position:0% +assumptions on this it's actually very + + + align:start position:0% +assumptions on this it's actually very +similar to last time. + + align:start position:0% +similar to last time. + + + align:start position:0% +similar to last time. +Okay. + + align:start position:0% + + + + align:start position:0% + +So the proof is to double count a + + align:start position:0% +So the proof is to double count a + + + align:start position:0% +So the proof is to double count a +certain quantity which which we which we + + align:start position:0% +certain quantity which which we which we + + + align:start position:0% +certain quantity which which we which we +called coincidences last time. So the + + align:start position:0% +called coincidences last time. So the + + + align:start position:0% +called coincidences last time. So the +key quantity called star + + align:start position:0% +key quantity called star + + + align:start position:0% +key quantity called star +is the number of + + align:start position:0% +is the number of + + + align:start position:0% +is the number of +b1 and b2 in x. So these are these are + + align:start position:0% +b1 and b2 in x. So these are these are + + + align:start position:0% +b1 and b2 in x. So these are these are +unit balls. + + align:start position:0% +unit balls. + + + align:start position:0% +unit balls. +So remember x is a set of unit balls. So + + align:start position:0% +So remember x is a set of unit balls. So + + + align:start position:0% +So remember x is a set of unit balls. So +these are two of the unit balls. Um and + + align:start position:0% +these are two of the unit balls. Um and + + + align:start position:0% +these are two of the unit balls. Um and +um theta and d I guess we'll say they're + + align:start position:0% +um theta and d I guess we'll say they're + + + align:start position:0% +um theta and d I guess we'll say they're +not equal to each other although that + + align:start position:0% +not equal to each other although that + + + align:start position:0% +not equal to each other although that +won't matter as much this time. um + + align:start position:0% +won't matter as much this time. um + + + align:start position:0% +won't matter as much this time. um +uh so that pi theta of b1 and pi theta + + align:start position:0% +uh so that pi theta of b1 and pi theta + + + align:start position:0% +uh so that pi theta of b1 and pi theta +of b2 are similar to each other and in + + align:start position:0% +of b2 are similar to each other and in + + + align:start position:0% +of b2 are similar to each other and in +this setting we won't count they don't + + align:start position:0% +this setting we won't count they don't + + + align:start position:0% +this setting we won't count they don't +have to be exactly the same I would just + + align:start position:0% +have to be exactly the same I would just + + + align:start position:0% +have to be exactly the same I would just +like them to overlap so my condition + + align:start position:0% +like them to overlap so my condition + + + align:start position:0% +like them to overlap so my condition +will be that the intersection of these + + align:start position:0% +will be that the intersection of these + + + align:start position:0% +will be that the intersection of these +is non empty so that's my key quantity + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +actually in this setup. I'm going to I'm + + align:start position:0% +actually in this setup. I'm going to I'm + + + align:start position:0% +actually in this setup. I'm going to I'm +going to allow them to be equal to each + + align:start position:0% +going to allow them to be equal to each + + + align:start position:0% +going to allow them to be equal to each +other. Um that makes the double counting + + align:start position:0% +other. Um that makes the double counting + + + align:start position:0% +other. Um that makes the double counting +a little easier and in a sense it's + + align:start position:0% +a little easier and in a sense it's + + + align:start position:0% +a little easier and in a sense it's +we'll see it's it's part of what's up + + align:start position:0% +we'll see it's it's part of what's up + + + align:start position:0% +we'll see it's it's part of what's up +here. + + align:start position:0% +here. + + + align:start position:0% +here. +Okay. So um so there's a lower bound + + align:start position:0% +Okay. So um so there's a lower bound + + + align:start position:0% +Okay. So um so there's a lower bound +which is straightforward. + + align:start position:0% + + + + align:start position:0% + +The lower bound says that this this star + + align:start position:0% +The lower bound says that this this star + + + align:start position:0% +The lower bound says that this this star +is at least the number of directions + + align:start position:0% +is at least the number of directions + + + align:start position:0% +is at least the number of directions +times in each direction + + align:start position:0% +times in each direction + + + align:start position:0% +times in each direction +x over s^2 + + align:start position:0% +x over s^2 + + + align:start position:0% +x over s^2 +* s. + + align:start position:0% +* s. + + + align:start position:0% +* s. +So in each direction these x different + + align:start position:0% +So in each direction these x different + + + align:start position:0% +So in each direction these x different +balls have been projected into only s + + align:start position:0% +balls have been projected into only s + + + align:start position:0% +balls have been projected into only s +slots. So a typical slot has x over s + + align:start position:0% +slots. So a typical slot has x over s + + + align:start position:0% +slots. So a typical slot has x over s +balls in its fiber. And so we have this + + align:start position:0% +balls in its fiber. And so we have this + + + align:start position:0% +balls in its fiber. And so we have this +many squared choices for to pick B1 and + + align:start position:0% +many squared choices for to pick B1 and + + + align:start position:0% +many squared choices for to pick B1 and +B2 in the same five + + align:start position:0% +B2 in the same five + + + align:start position:0% +B2 in the same five +s times. So lower bound is is really the + + align:start position:0% +s times. So lower bound is is really the + + + align:start position:0% +s times. So lower bound is is really the +same as last time. + + align:start position:0% +same as last time. + + + align:start position:0% +same as last time. +Same as last time, same as the homework. + + align:start position:0% + + + + align:start position:0% + +Okay. So now let's look at the upper + + align:start position:0% +Okay. So now let's look at the upper + + + align:start position:0% +Okay. So now let's look at the upper +bound. + + align:start position:0% + + + + align:start position:0% + +So I will uh for now I'll fix B1 B2 and + + align:start position:0% +So I will uh for now I'll fix B1 B2 and + + + align:start position:0% +So I will uh for now I'll fix B1 B2 and +I'll say that the distance between B1 + + align:start position:0% +I'll say that the distance between B1 + + + align:start position:0% +I'll say that the distance between B1 +and B2 is around R. + + align:start position:0% +and B2 is around R. + + + align:start position:0% +and B2 is around R. +Um so here's my picture + + align:start position:0% +Um so here's my picture + + + align:start position:0% +Um so here's my picture +B1 and B2 and the distance between them + + align:start position:0% +B1 and B2 and the distance between them + + + align:start position:0% +B1 and B2 and the distance between them +is around R. + + align:start position:0% +is around R. + + + align:start position:0% +is around R. +Okay. So now I'm interested in + + align:start position:0% +Okay. So now I'm interested in + + + align:start position:0% +Okay. So now I'm interested in +projections where the projection of B1 + + align:start position:0% +projections where the projection of B1 + + + align:start position:0% +projections where the projection of B1 +and the projection of B2 overlap. And so + + align:start position:0% +and the projection of B2 overlap. And so + + + align:start position:0% +and the projection of B2 overlap. And so +the angles for those projections are in + + align:start position:0% +the angles for those projections are in + + + align:start position:0% +the angles for those projections are in +a little angular range. The angle of the + + align:start position:0% +a little angular range. The angle of the + + + align:start position:0% +a little angular range. The angle of the +projection must be somewhere in this + + align:start position:0% +projection must be somewhere in this + + + align:start position:0% +projection must be somewhere in this +range here. + + align:start position:0% + + + + align:start position:0% + +So what um what I'll say is let's say + + align:start position:0% +So what um what I'll say is let's say + + + align:start position:0% +So what um what I'll say is let's say +that V is the direction from B1 to to to + + align:start position:0% +that V is the direction from B1 to to to + + + align:start position:0% +that V is the direction from B1 to to to +B2. So v is um center of b2 minus center + + align:start position:0% +B2. So v is um center of b2 minus center + + + align:start position:0% +B2. So v is um center of b2 minus center +of b1 + + align:start position:0% +of b1 + + + align:start position:0% +of b1 +over the norm of that. + + align:start position:0% + + + + align:start position:0% + +And + + align:start position:0% +And + + + align:start position:0% +And +if pi theta of b1 intersect pi theta b2 + + align:start position:0% +if pi theta of b1 intersect pi theta b2 + + + align:start position:0% +if pi theta of b1 intersect pi theta b2 +is not empty + + align:start position:0% +is not empty + + + align:start position:0% +is not empty +um then + + align:start position:0% +um then + + + align:start position:0% +um then +theta must be pretty close to v. What + + align:start position:0% +theta must be pretty close to v. What + + + align:start position:0% +theta must be pretty close to v. What +I'll say is that the angle + + align:start position:0% +I'll say is that the angle + + + align:start position:0% +I'll say is that the angle +between theta and v is smaller than + + align:start position:0% +between theta and v is smaller than + + + align:start position:0% +between theta and v is smaller than +around 1 / r. + + align:start position:0% + + + + align:start position:0% + +Okay. + + align:start position:0% +Okay. + + + align:start position:0% +Okay. +Um so now + + align:start position:0% +Um so now + + + align:start position:0% +Um so now +the number of theta so that pi theta of + + align:start position:0% +the number of theta so that pi theta of + + + align:start position:0% +the number of theta so that pi theta of +b1 intersect pi theta of b2 is not empty + + align:start position:0% + + + + align:start position:0% + +that would be bounded by well the number + + align:start position:0% +that would be bounded by well the number + + + align:start position:0% +that would be bounded by well the number +of directions in this little arc. So + + align:start position:0% +of directions in this little arc. So + + + align:start position:0% +of directions in this little arc. So +that would be nd of 1 / r. So we see the + + align:start position:0% +that would be nd of 1 / r. So we see the + + + align:start position:0% +that would be nd of 1 / r. So we see the +spacing uh the spacing function of the + + align:start position:0% +spacing uh the spacing function of the + + + align:start position:0% +spacing uh the spacing function of the +set d comes into play here. + + align:start position:0% + + + + align:start position:0% + +Okay, so that's what happens when we fix + + align:start position:0% +Okay, so that's what happens when we fix + + + align:start position:0% +Okay, so that's what happens when we fix +B1 and B2. + + align:start position:0% +B1 and B2. + + + align:start position:0% +B1 and B2. +And the case B1 equals B2 is allowed. + + align:start position:0% +And the case B1 equals B2 is allowed. + + + align:start position:0% +And the case B1 equals B2 is allowed. +And I'll make the slightly funny + + align:start position:0% +And I'll make the slightly funny + + + align:start position:0% +And I'll make the slightly funny +convention that then R is one. They're + + align:start position:0% +convention that then R is one. They're + + + align:start position:0% +convention that then R is one. They're +unit ball. So the distance between them + + align:start position:0% +unit ball. So the distance between them + + + align:start position:0% +unit ball. So the distance between them +is sort of one. And this is true. Then I + + align:start position:0% +is sort of one. And this is true. Then I + + + align:start position:0% +is sort of one. And this is true. Then I +mean V is not well defined, but this + + align:start position:0% +mean V is not well defined, but this + + + align:start position:0% +mean V is not well defined, but this +condition includes the whole range of + + align:start position:0% +condition includes the whole range of + + + align:start position:0% +condition includes the whole range of +angles. So it's it's true. + + align:start position:0% + + + + align:start position:0% + +Okay. + + align:start position:0% +Okay. + + + align:start position:0% +Okay. +So look if B1 equals B2 we take little R + + align:start position:0% +So look if B1 equals B2 we take little R + + + align:start position:0% +So look if B1 equals B2 we take little R +equals 1 and it's slightly exceptional + + align:start position:0% +equals 1 and it's slightly exceptional + + + align:start position:0% +equals 1 and it's slightly exceptional +but but all the bounds are true. + + align:start position:0% + + + + align:start position:0% + +Okay. + + align:start position:0% +Okay. + + + align:start position:0% +Okay. +So if we want to upper bound star now we + + align:start position:0% +So if we want to upper bound star now we + + + align:start position:0% +So if we want to upper bound star now we +need to count the number of choices for + + align:start position:0% +need to count the number of choices for + + + align:start position:0% +need to count the number of choices for +B1 and B2. + + align:start position:0% + + + + align:start position:0% + +So now I'm interested in the number of + + align:start position:0% +So now I'm interested in the number of + + + align:start position:0% +So now I'm interested in the number of +pairs + + align:start position:0% +pairs + + + align:start position:0% +pairs +B1, B2, and X with the property that the + + align:start position:0% +B1, B2, and X with the property that the + + + align:start position:0% +B1, B2, and X with the property that the +distance from B1 to B2 is at most R. + + align:start position:0% +distance from B1 to B2 is at most R. + + + align:start position:0% +distance from B1 to B2 is at most R. +Okay, how big is that? Well, I have norm + + align:start position:0% +Okay, how big is that? Well, I have norm + + + align:start position:0% +Okay, how big is that? Well, I have norm +of X choices for B1. + + align:start position:0% +of X choices for B1. + + + align:start position:0% +of X choices for B1. +But once I choose B1, I don't have all + + align:start position:0% +But once I choose B1, I don't have all + + + align:start position:0% +But once I choose B1, I don't have all +that many choices for B2 because B2 has + + align:start position:0% +that many choices for B2 because B2 has + + + align:start position:0% +that many choices for B2 because B2 has +to be close to B1. It has to be in a + + align:start position:0% +to be close to B1. It has to be in a + + + align:start position:0% +to be close to B1. It has to be in a +little R ball. + + align:start position:0% +little R ball. + + + align:start position:0% +little R ball. +So the number of choices for B2 is at + + align:start position:0% +So the number of choices for B2 is at + + + align:start position:0% +So the number of choices for B2 is at +most nx of R. So at this moment the + + align:start position:0% +most nx of R. So at this moment the + + + align:start position:0% +most nx of R. So at this moment the +spacing function of X comes into play. + + align:start position:0% + + + + align:start position:0% + +Okay. So now we can combine these to to + + align:start position:0% +Okay. So now we can combine these to to + + + align:start position:0% +Okay. So now we can combine these to to +upper bound star. + + align:start position:0% +upper bound star. + + + align:start position:0% +upper bound star. +So star is um is now upper bounded by + + align:start position:0% +So star is um is now upper bounded by + + + align:start position:0% +So star is um is now upper bounded by +x * nx of r time n d of 1 / r + + align:start position:0% +x * nx of r time n d of 1 / r + + + align:start position:0% +x * nx of r time n d of 1 / r +uh ah sorry so star + + align:start position:0% +uh ah sorry so star + + + align:start position:0% +uh ah sorry so star +is upperbounded by the sum over the + + align:start position:0% +is upperbounded by the sum over the + + + align:start position:0% +is upperbounded by the sum over the +diatic r + + align:start position:0% + + + + align:start position:0% + +of this quantity. + + align:start position:0% + + + + align:start position:0% + +Okay, so let me say why. So star is this + + align:start position:0% +Okay, so let me say why. So star is this + + + align:start position:0% +Okay, so let me say why. So star is this +set of coincidences. + + align:start position:0% +set of coincidences. + + + align:start position:0% +set of coincidences. +It's a B1 and B2 and a theta. And for + + align:start position:0% +It's a B1 and B2 and a theta. And for + + + align:start position:0% +It's a B1 and B2 and a theta. And for +each coincidence, I know I I sort these + + align:start position:0% +each coincidence, I know I I sort these + + + align:start position:0% +each coincidence, I know I I sort these +coincidences by the distance from B1 to + + align:start position:0% +coincidences by the distance from B1 to + + + align:start position:0% +coincidences by the distance from B1 to +B2, which I call R. So I take the the + + align:start position:0% +B2, which I call R. So I take the the + + + align:start position:0% +B2, which I call R. So I take the the +coincidences where the distance is + + align:start position:0% +coincidences where the distance is + + + align:start position:0% +coincidences where the distance is +around R, and I sum over the possible + + align:start position:0% +around R, and I sum over the possible + + + align:start position:0% +around R, and I sum over the possible +Rs. Once I fixed R, um, I have this many + + align:start position:0% +Rs. Once I fixed R, um, I have this many + + + align:start position:0% +Rs. Once I fixed R, um, I have this many +choices for the pair B1 B2. And once I + + align:start position:0% +choices for the pair B1 B2. And once I + + + align:start position:0% +choices for the pair B1 B2. And once I +fixed B1 and B2, I have this many + + align:start position:0% +fixed B1 and B2, I have this many + + + align:start position:0% +fixed B1 and B2, I have this many +choices for theta. + + align:start position:0% + + + + align:start position:0% + +So that's that. + + align:start position:0% + + + + align:start position:0% + +Okay. + + align:start position:0% +Okay. + + + align:start position:0% +Okay. +Uh, the rest is algebra. I'll sketch it + + align:start position:0% +Uh, the rest is algebra. I'll sketch it + + + align:start position:0% +Uh, the rest is algebra. I'll sketch it +quickly on the board and that'll be the + + align:start position:0% +quickly on the board and that'll be the + + + align:start position:0% +quickly on the board and that'll be the +end of the proof and then we'll pause to + + align:start position:0% +end of the proof and then we'll pause to + + + align:start position:0% +end of the proof and then we'll pause to +digest and check it. + + align:start position:0% +digest and check it. + + + align:start position:0% +digest and check it. +Okay. So al together + + align:start position:0% +Okay. So al together + + + align:start position:0% +Okay. So al together +we have x^2 s inverse d is bounded by + + align:start position:0% +we have x^2 s inverse d is bounded by + + + align:start position:0% +we have x^2 s inverse d is bounded by +star which is bounded by + + align:start position:0% +star which is bounded by + + + align:start position:0% +star which is bounded by +the sum over r datic + + align:start position:0% +the sum over r datic + + + align:start position:0% +the sum over r datic +of x nx of r and d of 1 / r and then I + + align:start position:0% +of x nx of r and d of 1 / r and then I + + + align:start position:0% +of x nx of r and d of 1 / r and then I +just get the d by itself. + + align:start position:0% + + + + align:start position:0% + +If you move this stuff over to the other + + align:start position:0% +If you move this stuff over to the other + + + align:start position:0% +If you move this stuff over to the other +side, you get the formula on the board. + + align:start position:0% + + + + align:start position:0% + +Okay, so let's pause there for questions + + align:start position:0% +Okay, so let's pause there for questions + + + align:start position:0% +Okay, so let's pause there for questions +and comments. + + align:start position:0% + + + + align:start position:0% + +All right. + + align:start position:0% +All right. + + + align:start position:0% +All right. +All right. So, um, so I wanted to, uh, + + align:start position:0% +All right. So, um, so I wanted to, uh, + + + align:start position:0% +All right. So, um, so I wanted to, uh, +get a sense of start to explore this + + align:start position:0% +get a sense of start to explore this + + + align:start position:0% +get a sense of start to explore this +function nx of r by looking at a few + + align:start position:0% +function nx of r by looking at a few + + + align:start position:0% +function nx of r by looking at a few +different examples of sets x and writing + + align:start position:0% +different examples of sets x and writing + + + align:start position:0% +different examples of sets x and writing +down what is nx of r. It's not + + align:start position:0% +down what is nx of r. It's not + + + align:start position:0% +down what is nx of r. It's not +difficult, but having a few different + + align:start position:0% +difficult, but having a few different + + + align:start position:0% +difficult, but having a few different +examples in our mind, it'll help to + + align:start position:0% +examples in our mind, it'll help to + + + align:start position:0% +examples in our mind, it'll help to +orient us as we keep going. + + align:start position:0% +orient us as we keep going. + + + align:start position:0% +orient us as we keep going. +um and and actually will help also to + + align:start position:0% +um and and actually will help also to + + + align:start position:0% +um and and actually will help also to +digest this formula. So this this proof + + align:start position:0% +digest this formula. So this this proof + + + align:start position:0% +digest this formula. So this this proof +was clean. This formula is a little bit + + align:start position:0% +was clean. This formula is a little bit + + + align:start position:0% +was clean. This formula is a little bit +messy. So after looking at some + + align:start position:0% +messy. So after looking at some + + + align:start position:0% +messy. So after looking at some +examples, we'll digest this formula and + + align:start position:0% +examples, we'll digest this formula and + + + align:start position:0% +examples, we'll digest this formula and +think about a situation where it works + + align:start position:0% +think about a situation where it works + + + align:start position:0% +think about a situation where it works +out a little more cleanly. + + align:start position:0% + + + + align:start position:0% + +All right. + + align:start position:0% +All right. + + + align:start position:0% +All right. +[Applause] + + align:start position:0% + + + + align:start position:0% + +All right. So examples + + align:start position:0% +All right. So examples + + + align:start position:0% +All right. So examples +for n sub x sub rar. + + align:start position:0% +for n sub x sub rar. + + + align:start position:0% +for n sub x sub rar. +Okay. So number one, x is the one + + align:start position:0% +Okay. So number one, x is the one + + + align:start position:0% +Okay. So number one, x is the one +neighborhood + + align:start position:0% +neighborhood + + + align:start position:0% +neighborhood +of a curve like a nice like a circle or + + align:start position:0% +of a curve like a nice like a circle or + + + align:start position:0% +of a curve like a nice like a circle or +parabola or something. So here's the + + align:start position:0% +parabola or something. So here's the + + + align:start position:0% +parabola or something. So here's the +ball of radius r and inside of there I + + align:start position:0% +ball of radius r and inside of there I + + + align:start position:0% +ball of radius r and inside of there I +have a nice curve and all along the + + align:start position:0% +have a nice curve and all along the + + + align:start position:0% +have a nice curve and all along the +curve I have unit balls. + + align:start position:0% +curve I have unit balls. + + + align:start position:0% +curve I have unit balls. +That's x. + + align:start position:0% +That's x. + + + align:start position:0% +That's x. +So if I have this set, how many unit + + align:start position:0% +So if I have this set, how many unit + + + align:start position:0% +So if I have this set, how many unit +balls do I have in a ball of radius + + align:start position:0% +balls do I have in a ball of radius + + + align:start position:0% +balls do I have in a ball of radius +little r? + + align:start position:0% +little r? + + + align:start position:0% +little r? +That would be around r. + + align:start position:0% + + + + align:start position:0% + +Okay. + + align:start position:0% +Okay. + + + align:start position:0% +Okay. +Do a second example. Um + + align:start position:0% +Do a second example. Um + + + align:start position:0% +Do a second example. Um +second example, it would be very spread + + align:start position:0% +second example, it would be very spread + + + align:start position:0% +second example, it would be very spread +out. You know, if you imagine that these + + align:start position:0% +out. You know, if you imagine that these + + + align:start position:0% +out. You know, if you imagine that these +points are like positive charges that + + align:start position:0% +points are like positive charges that + + + align:start position:0% +points are like positive charges that +repel each other and they push as far + + align:start position:0% +repel each other and they push as far + + + align:start position:0% +repel each other and they push as far +away from each other as possible, they + + align:start position:0% +away from each other as possible, they + + + align:start position:0% +away from each other as possible, they +would arrange themselves in something + + align:start position:0% +would arrange themselves in something + + + align:start position:0% +would arrange themselves in something +like a lattice inside of here. + + align:start position:0% +like a lattice inside of here. + + + align:start position:0% +like a lattice inside of here. +So, okay. So, I'll call this the uh well + + align:start position:0% +So, okay. So, I'll call this the uh well + + + align:start position:0% +So, okay. So, I'll call this the uh well +spaced example, the most spread out + + align:start position:0% +spaced example, the most spread out + + + align:start position:0% +spaced example, the most spread out +example. So, it looks like this. + + align:start position:0% + + + + align:start position:0% + +So it's a let's say it's a well spaced n + + align:start position:0% +So it's a let's say it's a well spaced n + + + align:start position:0% +So it's a let's say it's a well spaced n +byn grid + + align:start position:0% +byn grid + + + align:start position:0% +byn grid +and so the distance between neighboring + + align:start position:0% +and so the distance between neighboring + + + align:start position:0% +and so the distance between neighboring +balls would be like r /n. + + align:start position:0% + + + + align:start position:0% + +Okay so now what would nx of r be like? + + align:start position:0% +Okay so now what would nx of r be like? + + + align:start position:0% +Okay so now what would nx of r be like? +Um well it would be one for quite a + + align:start position:0% +Um well it would be one for quite a + + + align:start position:0% +Um well it would be one for quite a +while if our radius is less than rn. um + + align:start position:0% +while if our radius is less than rn. um + + + align:start position:0% +while if our radius is less than rn. um +then this would be one but then + + align:start position:0% +then this would be one but then + + + align:start position:0% +then this would be one but then +eventually as the radius gets bigger it + + align:start position:0% +eventually as the radius gets bigger it + + + align:start position:0% +eventually as the radius gets bigger it +would get bigger than one and at that + + align:start position:0% +would get bigger than one and at that + + + align:start position:0% +would get bigger than one and at that +point it would be um its fair share of + + align:start position:0% +point it would be um its fair share of + + + align:start position:0% +point it would be um its fair share of +the total number total size of x. So + + align:start position:0% +the total number total size of x. So + + + align:start position:0% +the total number total size of x. So +once once r is bigger than this + + align:start position:0% +once once r is bigger than this + + + align:start position:0% +once once r is bigger than this +threshold, every little r ball contains + + align:start position:0% +threshold, every little r ball contains + + + align:start position:0% +threshold, every little r ball contains +the same amount of x. And so the density + + align:start position:0% +the same amount of x. And so the density + + + align:start position:0% +the same amount of x. And so the density +of x is like n^2 r 2. The area of the + + align:start position:0% +of x is like n^2 r 2. The area of the + + + align:start position:0% +of x is like n^2 r 2. The area of the +ball is like this. + + align:start position:0% + + + + align:start position:0% + +Okay. And um I'll do a third example + + align:start position:0% +Okay. And um I'll do a third example + + + align:start position:0% +Okay. And um I'll do a third example +which is the points could be very um uh + + align:start position:0% +which is the points could be very um uh + + + align:start position:0% +which is the points could be very um uh +clustered + + align:start position:0% +clustered + + + align:start position:0% +clustered +cluster. + + align:start position:0% +cluster. + + + align:start position:0% +cluster. +So we could have n squared unit balls + + align:start position:0% + + + + align:start position:0% + +in um in an n ball. So the the picture + + align:start position:0% +in um in an n ball. So the the picture + + + align:start position:0% +in um in an n ball. So the the picture +would be like this. We have our ball of + + align:start position:0% +would be like this. We have our ball of + + + align:start position:0% +would be like this. We have our ball of +radius r. Inside of there we have a + + align:start position:0% +radius r. Inside of there we have a + + + align:start position:0% +radius r. Inside of there we have a +smaller ball of radius n and we pack the + + align:start position:0% +smaller ball of radius n and we pack the + + + align:start position:0% +smaller ball of radius n and we pack the +smaller ball with unit balls of x. + + align:start position:0% +smaller ball with unit balls of x. + + + align:start position:0% +smaller ball with unit balls of x. +Okay. So now what is uh n subx of r? + + align:start position:0% + + + + align:start position:0% + +Well it grows like r 2 until r is as big + + align:start position:0% +Well it grows like r 2 until r is as big + + + align:start position:0% +Well it grows like r 2 until r is as big +as this n ball. And after that there are + + align:start position:0% +as this n ball. And after that there are + + + align:start position:0% +as this n ball. And after that there are +only n squared balls at all. So you can + + align:start position:0% +only n squared balls at all. So you can + + + align:start position:0% +only n squared balls at all. So you can +make a little r bigger. It doesn't grow + + align:start position:0% +make a little r bigger. It doesn't grow + + + align:start position:0% +make a little r bigger. It doesn't grow +anymore. So it caps off at n^ squ if r + + align:start position:0% +anymore. So it caps off at n^ squ if r + + + align:start position:0% +anymore. So it caps off at n^ squ if r +is bigger than n. + + align:start position:0% + + + + align:start position:0% + +Okay. + + align:start position:0% +Okay. + + + align:start position:0% +Okay. +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +So now I will draw um some pictures of + + align:start position:0% +So now I will draw um some pictures of + + + align:start position:0% +So now I will draw um some pictures of +of of these three functions. + + align:start position:0% +of of these three functions. + + + align:start position:0% +of of these three functions. +You can compare them. + + align:start position:0% + + + + align:start position:0% + +Okay, we'll do some pictures. + + align:start position:0% + + + + align:start position:0% + +I'm going to normalize in my pictures. I + + align:start position:0% +I'm going to normalize in my pictures. I + + + align:start position:0% +I'm going to normalize in my pictures. I +have to choose an n. I'm going to choose + + align:start position:0% +have to choose an n. I'm going to choose + + + align:start position:0% +have to choose an n. I'm going to choose +n= r to the half. Uh, and that's helpful + + align:start position:0% +n= r to the half. Uh, and that's helpful + + + align:start position:0% +n= r to the half. Uh, and that's helpful +because it says that the total size of x + + align:start position:0% +because it says that the total size of x + + + align:start position:0% +because it says that the total size of x +is around r in all three examples. It + + align:start position:0% +is around r in all three examples. It + + + align:start position:0% +is around r in all three examples. It +makes them a little easier to compare + + align:start position:0% +makes them a little easier to compare + + + align:start position:0% +makes them a little easier to compare +with each other. + + align:start position:0% +with each other. + + + align:start position:0% +with each other. +Okay. So now I'll make a graph. + + align:start position:0% +Okay. So now I'll make a graph. + + + align:start position:0% +Okay. So now I'll make a graph. +Basically I'd like to put on this axis + + align:start position:0% +Basically I'd like to put on this axis + + + align:start position:0% +Basically I'd like to put on this axis +little r and on this axis n subx of + + align:start position:0% +little r and on this axis n subx of + + + align:start position:0% +little r and on this axis n subx of +little r. Um but this graph like many + + align:start position:0% +little r. Um but this graph like many + + + align:start position:0% +little r. Um but this graph like many +graphs in math looks nicer if we use log + + align:start position:0% +graphs in math looks nicer if we use log + + + align:start position:0% +graphs in math looks nicer if we use log +is a log log plot. So on this on this + + align:start position:0% +is a log log plot. So on this on this + + + align:start position:0% +is a log log plot. So on this on this +axis I'm going to put the log of little + + align:start position:0% +axis I'm going to put the log of little + + + align:start position:0% +axis I'm going to put the log of little +r and then the nicest base for that is + + align:start position:0% +r and then the nicest base for that is + + + align:start position:0% +r and then the nicest base for that is +big r. This goes from 0 to one. And on + + align:start position:0% +big r. This goes from 0 to one. And on + + + align:start position:0% +big r. This goes from 0 to one. And on +this axis, I'm going to put the log of n + + align:start position:0% +this axis, I'm going to put the log of n + + + align:start position:0% +this axis, I'm going to put the log of n +subx of r. And it's natural to use the + + align:start position:0% +subx of r. And it's natural to use the + + + align:start position:0% +subx of r. And it's natural to use the +same base. So this goes from 0 to one. + + align:start position:0% +same base. So this goes from 0 to one. + + + align:start position:0% +same base. So this goes from 0 to one. +This could go above one potentially, but + + align:start position:0% +This could go above one potentially, but + + + align:start position:0% +This could go above one potentially, but +because the size of x happens to be r, + + align:start position:0% +because the size of x happens to be r, + + + align:start position:0% +because the size of x happens to be r, +we're going to stop there. + + align:start position:0% +we're going to stop there. + + + align:start position:0% +we're going to stop there. +Okay. So now what do these three + + align:start position:0% +Okay. So now what do these three + + + align:start position:0% +Okay. So now what do these three +examples look like? The first example is + + align:start position:0% +examples look like? The first example is + + + align:start position:0% +examples look like? The first example is +a straight line. + + align:start position:0% + + + + align:start position:0% + +So that's example one. + + align:start position:0% + + + + align:start position:0% + +Um, + + align:start position:0% + + + + align:start position:0% + +the second example grows more slowly + + align:start position:0% +the second example grows more slowly + + + align:start position:0% +the second example grows more slowly +than the straight line for a while. It + + align:start position:0% +than the straight line for a while. It + + + align:start position:0% +than the straight line for a while. It +doesn't grow at all for a while and then + + align:start position:0% +doesn't grow at all for a while and then + + + align:start position:0% +doesn't grow at all for a while and then +it grows quickly to catch up. So that's + + align:start position:0% +it grows quickly to catch up. So that's + + + align:start position:0% +it grows quickly to catch up. So that's +the second example. It lies below the + + align:start position:0% +the second example. It lies below the + + + align:start position:0% +the second example. It lies below the +straight line. Uh and then the third + + align:start position:0% +straight line. Uh and then the third + + + align:start position:0% +straight line. Uh and then the third +example grows more quickly than the + + align:start position:0% +example grows more quickly than the + + + align:start position:0% +example grows more quickly than the +first example and then it reaches a + + align:start position:0% +first example and then it reaches a + + + align:start position:0% +first example and then it reaches a +certain point and it stops growing. So + + align:start position:0% +certain point and it stops growing. So + + + align:start position:0% +certain point and it stops growing. So +it looks like this and it lies above the + + align:start position:0% +it looks like this and it lies above the + + + align:start position:0% +it looks like this and it lies above the +straight line. + + align:start position:0% + + + + align:start position:0% + +Okay. So um so in this theory there + + align:start position:0% +Okay. So um so in this theory there + + + align:start position:0% +Okay. So um so in this theory there +turns out to be that things that grow + + align:start position:0% +turns out to be that things that grow + + + align:start position:0% +turns out to be that things that grow +the the straight line case is an + + align:start position:0% +the the straight line case is an + + + align:start position:0% +the the straight line case is an +important case and then there's an + + align:start position:0% +important case and then there's an + + + align:start position:0% +important case and then there's an +important distinction between things + + align:start position:0% +important distinction between things + + + align:start position:0% +important distinction between things +that are below the straight line things + + align:start position:0% +that are below the straight line things + + + align:start position:0% +that are below the straight line things +that are above the straight line. + + align:start position:0% + + + + align:start position:0% + +Um so the straight line case + + align:start position:0% + + + + align:start position:0% + +would be that n that that the size of x + + align:start position:0% +would be that n that that the size of x + + + align:start position:0% +would be that n that that the size of x +would be r to the alpha for some alpha + + align:start position:0% +would be r to the alpha for some alpha + + + align:start position:0% +would be r to the alpha for some alpha +and then n sub little r of x or n subx + + align:start position:0% +and then n sub little r of x or n subx + + + align:start position:0% +and then n sub little r of x or n subx +of little r + + align:start position:0% +of little r + + + align:start position:0% +of little r +would be little r to the alpha. That + + align:start position:0% +would be little r to the alpha. That + + + align:start position:0% +would be little r to the alpha. That +would be the straight line case. + + align:start position:0% +would be the straight line case. + + + align:start position:0% +would be the straight line case. +And the uh below the straight line case, + + align:start position:0% + + + + align:start position:0% + +uh x would still be r to the alpha. So + + align:start position:0% +uh x would still be r to the alpha. So + + + align:start position:0% +uh x would still be r to the alpha. So +the end point would be the same, but now + + align:start position:0% +the end point would be the same, but now + + + align:start position:0% +the end point would be the same, but now +in the middle, we're going to go below + + align:start position:0% +in the middle, we're going to go below + + + align:start position:0% +in the middle, we're going to go below +what we had before. So n subx of r would + + align:start position:0% +what we had before. So n subx of r would + + + align:start position:0% +what we had before. So n subx of r would +be at most r + + align:start position:0% + + + + align:start position:0% + +Okay. So this thing here is called a + + align:start position:0% +Okay. So this thing here is called a + + + align:start position:0% +Okay. So this thing here is called a +regular alpha dimensional + + align:start position:0% +regular alpha dimensional + + + align:start position:0% +regular alpha dimensional +spacing + + align:start position:0% +spacing + + + align:start position:0% +spacing +and this thing is called a alpha + + align:start position:0% +and this thing is called a alpha + + + align:start position:0% +and this thing is called a alpha +dimensional spacing. + + align:start position:0% + + + + align:start position:0% + +Um + + align:start position:0% +Um + + + align:start position:0% +Um +I'd like and I'd like to make one more + + align:start position:0% +I'd like and I'd like to make one more + + + align:start position:0% +I'd like and I'd like to make one more +definition. And I'll say that X has a + + align:start position:0% +definition. And I'll say that X has a + + + align:start position:0% +definition. And I'll say that X has a +housegrowth spacing + + align:start position:0% + + + + align:start position:0% + +if it has alpha dimensional spacing for + + align:start position:0% +if it has alpha dimensional spacing for + + + align:start position:0% +if it has alpha dimensional spacing for +some of + + align:start position:0% + + + + align:start position:0% + +but another way of saying that is if you + + align:start position:0% +but another way of saying that is if you + + + align:start position:0% +but another way of saying that is if you +look at how many points of X are in a + + align:start position:0% +look at how many points of X are in a + + + align:start position:0% +look at how many points of X are in a +ball of radius R to the beta it's + + align:start position:0% +ball of radius R to the beta it's + + + align:start position:0% +ball of radius R to the beta it's +bounded by the total number of points of + + align:start position:0% +bounded by the total number of points of + + + align:start position:0% +bounded by the total number of points of +x to the beta. + + align:start position:0% + + + + align:start position:0% + +And this is this is equivalent. This is + + align:start position:0% +And this is this is equivalent. This is + + + align:start position:0% +And this is this is equivalent. This is +still below the straight line. + + align:start position:0% + + + + align:start position:0% + +Okay. So over here um we would have we + + align:start position:0% +Okay. So over here um we would have we + + + align:start position:0% +Okay. So over here um we would have we +have example one and and in general if + + align:start position:0% +have example one and and in general if + + + align:start position:0% +have example one and and in general if +you have any if you have a submanifold + + align:start position:0% +you have any if you have a submanifold + + + align:start position:0% +you have any if you have a submanifold +in any dimensional space it will behave + + align:start position:0% +in any dimensional space it will behave + + + align:start position:0% +in any dimensional space it will behave +like this and alpha is the dimension of + + align:start position:0% +like this and alpha is the dimension of + + + align:start position:0% +like this and alpha is the dimension of +the sub manifold. Also some self- + + align:start position:0% +the sub manifold. Also some self- + + + align:start position:0% +the sub manifold. Also some self- +similar caner set kind of fractals like + + align:start position:0% +similar caner set kind of fractals like + + + align:start position:0% +similar caner set kind of fractals like +the caner set um have this kind of + + align:start position:0% +the caner set um have this kind of + + + align:start position:0% +the caner set um have this kind of +spacing where alpha would be the + + align:start position:0% +spacing where alpha would be the + + + align:start position:0% +spacing where alpha would be the +dimension of the of your caner set. + + align:start position:0% +dimension of the of your caner set. + + + align:start position:0% +dimension of the of your caner set. +That's why it's called alpha + + align:start position:0% +That's why it's called alpha + + + align:start position:0% +That's why it's called alpha +dimensional. + + align:start position:0% +dimensional. + + + align:start position:0% +dimensional. +Um + + align:start position:0% +Um + + + align:start position:0% +Um +and um and these things this thing + + align:start position:0% +and um and these things this thing + + + align:start position:0% +and um and these things this thing +called housedorf spacing I called it + + align:start position:0% +called housedorf spacing I called it + + + align:start position:0% +called housedorf spacing I called it +that because it it appears naturally in + + align:start position:0% +that because it it appears naturally in + + + align:start position:0% +that because it it appears naturally in +the theory of housed dorf dimensions. + + align:start position:0% + + + + align:start position:0% + +Um + + align:start position:0% + + + + align:start position:0% + +yeah, so it's maybe worth saying briefly + + align:start position:0% +yeah, so it's maybe worth saying briefly + + + align:start position:0% +yeah, so it's maybe worth saying briefly +that in the geometric measure theory + + align:start position:0% +that in the geometric measure theory + + + align:start position:0% +that in the geometric measure theory +literature, a lot of the stuff we're + + align:start position:0% +literature, a lot of the stuff we're + + + align:start position:0% +literature, a lot of the stuff we're +talking about today was originally + + align:start position:0% +talking about today was originally + + + align:start position:0% +talking about today was originally +described in the language of housedorf + + align:start position:0% +described in the language of housedorf + + + align:start position:0% +described in the language of housedorf +dimensions. Um but my impression is that + + align:start position:0% +dimensions. Um but my impression is that + + + align:start position:0% +dimensions. Um but my impression is that +that's not really that helpful. Like if + + align:start position:0% +that's not really that helpful. Like if + + + align:start position:0% +that's not really that helpful. Like if +we if we defined housedorf dimensions + + align:start position:0% +we if we defined housedorf dimensions + + + align:start position:0% +we if we defined housedorf dimensions +and then we wanted to prove things about + + align:start position:0% +and then we wanted to prove things about + + + align:start position:0% +and then we wanted to prove things about +housed dorf dimensions we would add an + + align:start position:0% +housed dorf dimensions we would add an + + + align:start position:0% +housed dorf dimensions we would add an +extra layer of definition and then we'd + + align:start position:0% +extra layer of definition and then we'd + + + align:start position:0% +extra layer of definition and then we'd +have to check the extra layer of + + align:start position:0% +have to check the extra layer of + + + align:start position:0% +have to check the extra layer of +definition. Um but then in all the + + align:start position:0% +definition. Um but then in all the + + + align:start position:0% +definition. Um but then in all the +applications that we'll talk about we + + align:start position:0% +applications that we'll talk about we + + + align:start position:0% +applications that we'll talk about we +would never use those definitions. We + + align:start position:0% +would never use those definitions. We + + + align:start position:0% +would never use those definitions. We +would go back to this theorem the way + + align:start position:0% +would go back to this theorem the way + + + align:start position:0% +would go back to this theorem the way +it's stated now and use that. Um, so I + + align:start position:0% +it's stated now and use that. Um, so I + + + align:start position:0% +it's stated now and use that. Um, so I +have a bit tentatively but I've come to + + align:start position:0% +have a bit tentatively but I've come to + + + align:start position:0% +have a bit tentatively but I've come to +the conclusion that house dorf dimension + + align:start position:0% +the conclusion that house dorf dimension + + + align:start position:0% +the conclusion that house dorf dimension +is not really a helpful notion for this + + align:start position:0% +is not really a helpful notion for this + + + align:start position:0% +is not really a helpful notion for this +subject and and so I'm going to leave it + + align:start position:0% +subject and and so I'm going to leave it + + + align:start position:0% +subject and and so I'm going to leave it +out. + + align:start position:0% + + + + align:start position:0% + +Okay. Um, but any questions or comments + + align:start position:0% +Okay. Um, but any questions or comments + + + align:start position:0% +Okay. Um, but any questions or comments +about these + + align:start position:0% +about these + + + align:start position:0% +about these +different ways that a set can be spaced? + + align:start position:0% +different ways that a set can be spaced? + + + align:start position:0% +different ways that a set can be spaced? +>> Yeah. + + align:start position:0% +>> Yeah. + + + align:start position:0% +>> Yeah. +>> I'm wondering like is the And the pro 01 + + align:start position:0% +>> I'm wondering like is the And the pro 01 + + + align:start position:0% +>> I'm wondering like is the And the pro 01 +for the pro lower bound. + + align:start position:0% +for the pro lower bound. + + + align:start position:0% +for the pro lower bound. +If we try to calculate lower bound for + + align:start position:0% +If we try to calculate lower bound for + + + align:start position:0% +If we try to calculate lower bound for +B1 B2 like is distance like somehow + + align:start position:0% +B1 B2 like is distance like somehow + + + align:start position:0% +B1 B2 like is distance like somehow +R from R1 to R2 like with that and + + align:start position:0% +R from R1 to R2 like with that and + + + align:start position:0% +R from R1 to R2 like with that and +compare this with the upper bound with + + align:start position:0% +compare this with the upper bound with + + + align:start position:0% +compare this with the upper bound with +different distance from B1 and B2. that + + align:start position:0% +different distance from B1 and B2. that + + + align:start position:0% +different distance from B1 and B2. that +information that + + align:start position:0% + + + + align:start position:0% + +>> yeah okay so the question is um when we + + align:start position:0% +>> yeah okay so the question is um when we + + + align:start position:0% +>> yeah okay so the question is um when we +were processing the upper bound for this + + align:start position:0% +were processing the upper bound for this + + + align:start position:0% +were processing the upper bound for this +we sorted it according to the distance + + align:start position:0% +we sorted it according to the distance + + + align:start position:0% +we sorted it according to the distance +so we really have a set star sub r where + + align:start position:0% +so we really have a set star sub r where + + + align:start position:0% +so we really have a set star sub r where +we add the condition that the distance + + align:start position:0% +we add the condition that the distance + + + align:start position:0% +we add the condition that the distance +from b1 to b2 is around r and the + + align:start position:0% +from b1 to b2 is around r and the + + + align:start position:0% +from b1 to b2 is around r and the +question is if if we looked at the lower + + align:start position:0% +question is if if we looked at the lower + + + align:start position:0% +question is if if we looked at the lower +bound we could also sort it by r and and + + align:start position:0% +bound we could also sort it by r and and + + + align:start position:0% +bound we could also sort it by r and and +would that be helpful yeah Um + + align:start position:0% +would that be helpful yeah Um + + + align:start position:0% +would that be helpful yeah Um +um yeah I that is a a good thing to look + + align:start position:0% +um yeah I that is a a good thing to look + + + align:start position:0% +um yeah I that is a a good thing to look +into. Off the top of my head I don't + + align:start position:0% +into. Off the top of my head I don't + + + align:start position:0% +into. Off the top of my head I don't +know if it would be helpful. Um you know + + align:start position:0% +know if it would be helpful. Um you know + + + align:start position:0% +know if it would be helpful. Um you know +it's uh our our lower bound with this s + + align:start position:0% +it's uh our our lower bound with this s + + + align:start position:0% +it's uh our our lower bound with this s +here depends on taking all of them. Um + + align:start position:0% +here depends on taking all of them. Um + + + align:start position:0% +here depends on taking all of them. Um +but it would be interesting. Yeah it + + align:start position:0% +but it would be interesting. Yeah it + + + align:start position:0% +but it would be interesting. Yeah it +would be interesting to think about. + + align:start position:0% + + + + align:start position:0% + +Other questions or comments? + + align:start position:0% + + + + align:start position:0% + +Okay. Okay. So, let me show you uh so so + + align:start position:0% +Okay. Okay. So, let me show you uh so so + + + align:start position:0% +Okay. Okay. So, let me show you uh so so +I so I claim so okay it seems that um + + align:start position:0% +I so I claim so okay it seems that um + + + align:start position:0% +I so I claim so okay it seems that um +this spacing condition + + align:start position:0% +this spacing condition + + + align:start position:0% +this spacing condition +say housedorf spacing is helpful in the + + align:start position:0% +say housedorf spacing is helpful in the + + + align:start position:0% +say housedorf spacing is helpful in the +theory. Um and one way that comes about + + align:start position:0% +theory. Um and one way that comes about + + + align:start position:0% +theory. Um and one way that comes about +is that a lot of the theorem statements + + align:start position:0% +is that a lot of the theorem statements + + + align:start position:0% +is that a lot of the theorem statements +become a lot cleaner if you put in house + + align:start position:0% +become a lot cleaner if you put in house + + + align:start position:0% +become a lot cleaner if you put in house +spacing. + + align:start position:0% +spacing. + + + align:start position:0% +spacing. +Um so let's do that here. Let's suppose + + align:start position:0% +Um so let's do that here. Let's suppose + + + align:start position:0% +Um so let's do that here. Let's suppose +that X and D have housed doororf spacing + + align:start position:0% +that X and D have housed doororf spacing + + + align:start position:0% +that X and D have housed doororf spacing +and we'll use that to simplify this + + align:start position:0% +and we'll use that to simplify this + + + align:start position:0% +and we'll use that to simplify this +thing. + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% + + + + align:start position:0% + +Okay. So corollary one real is that if + + align:start position:0% +Okay. So corollary one real is that if + + + align:start position:0% +Okay. So corollary one real is that if +we have the the setup + + align:start position:0% +we have the the setup + + + align:start position:0% +we have the the setup +and x and d are housedorf spacing + + align:start position:0% + + + + align:start position:0% + +then we get a simpler inequality which + + align:start position:0% +then we get a simpler inequality which + + + align:start position:0% +then we get a simpler inequality which +matches quite well what happens in + + align:start position:0% +matches quite well what happens in + + + align:start position:0% +matches quite well what happens in +finite fields. + + align:start position:0% +finite fields. + + + align:start position:0% +finite fields. +Then d is bounded by um s plus x. + + align:start position:0% + + + + align:start position:0% + +Okay. + + align:start position:0% +Okay. + + + align:start position:0% +Okay. +So, I'll prove this and then I'll try to + + align:start position:0% +So, I'll prove this and then I'll try to + + + align:start position:0% +So, I'll prove this and then I'll try to +argue actually. So, so okay. So, this + + align:start position:0% +argue actually. So, so okay. So, this + + + align:start position:0% +argue actually. So, so okay. So, this +looks a little nicer than before. It + + align:start position:0% +looks a little nicer than before. It + + + align:start position:0% +looks a little nicer than before. It +might still not look that nice to you. + + align:start position:0% +might still not look that nice to you. + + + align:start position:0% +might still not look that nice to you. +Um but I would summarize it like this. + + align:start position:0% +Um but I would summarize it like this. + + + align:start position:0% +Um but I would summarize it like this. +Um either + + align:start position:0% + + + + align:start position:0% + +either s e either s is pretty close to x + + align:start position:0% +either s e either s is pretty close to x + + + align:start position:0% +either s e either s is pretty close to x +or d is smaller than s and that's what + + align:start position:0% +or d is smaller than s and that's what + + + align:start position:0% +or d is smaller than s and that's what +we had in finite fields. So why is it if + + align:start position:0% +we had in finite fields. So why is it if + + + align:start position:0% +we had in finite fields. So why is it if +s is a lot smaller than x? This is much + + align:start position:0% +s is a lot smaller than x? This is much + + + align:start position:0% +s is a lot smaller than x? This is much +less than one. So we can rearrange that + + align:start position:0% +less than one. So we can rearrange that + + + align:start position:0% +less than one. So we can rearrange that +and we get that d is less than s. + + align:start position:0% + + + + align:start position:0% + +Okay. So, what's the proof? Well, um, + + align:start position:0% +Okay. So, what's the proof? Well, um, + + + align:start position:0% +Okay. So, what's the proof? Well, um, +we're going to have an expression like + + align:start position:0% +we're going to have an expression like + + + align:start position:0% +we're going to have an expression like +nx of r n d of 1 / r. + + align:start position:0% + + + + align:start position:0% + +And so now let's suppose + + align:start position:0% +And so now let's suppose + + + align:start position:0% +And so now let's suppose +that little r is big r to the beta. + + align:start position:0% +that little r is big r to the beta. + + + align:start position:0% +that little r is big r to the beta. +And um and then being housedorf + + align:start position:0% + + + + align:start position:0% + +it tells us that nx of r the beta n d of + + align:start position:0% +it tells us that nx of r the beta n d of + + + align:start position:0% +it tells us that nx of r the beta n d of +r the minus beta + + align:start position:0% +r the minus beta + + + align:start position:0% +r the minus beta +there that is bounded by x to the beta * + + align:start position:0% +there that is bounded by x to the beta * + + + align:start position:0% +there that is bounded by x to the beta * +d to the 1 - beta. + + align:start position:0% +d to the 1 - beta. + + + align:start position:0% +d to the 1 - beta. +That's what being housed tells us. + + align:start position:0% +That's what being housed tells us. + + + align:start position:0% +That's what being housed tells us. +So being house of dwarf allows us to to + + align:start position:0% +So being house of dwarf allows us to to + + + align:start position:0% +So being house of dwarf allows us to to +relate nx of r for any r to the size of + + align:start position:0% +relate nx of r for any r to the size of + + + align:start position:0% +relate nx of r for any r to the size of +x which is nx of big r and algebraically + + align:start position:0% +x which is nx of big r and algebraically + + + align:start position:0% +x which is nx of big r and algebraically +it works out like this and for d it + + align:start position:0% +it works out like this and for d it + + + align:start position:0% +it works out like this and for d it +works out like that. + + align:start position:0% +works out like that. + + + align:start position:0% +works out like that. +Okay. And then by amg this is smaller + + align:start position:0% +Okay. And then by amg this is smaller + + + align:start position:0% +Okay. And then by amg this is smaller +than x plus d. + + align:start position:0% +than x plus d. + + + align:start position:0% +than x plus d. +So every one of these complicated things + + align:start position:0% +So every one of these complicated things + + + align:start position:0% +So every one of these complicated things +they're all bounded by x plus d + + align:start position:0% +they're all bounded by x plus d + + + align:start position:0% +they're all bounded by x plus d +and the number of them is only log of r. + + align:start position:0% +and the number of them is only log of r. + + + align:start position:0% +and the number of them is only log of r. +So, okay, sorry. So, I should put a log + + align:start position:0% +So, okay, sorry. So, I should put a log + + + align:start position:0% +So, okay, sorry. So, I should put a log +of R here. + + align:start position:0% + + + + align:start position:0% + +Um, + + align:start position:0% +Um, + + + align:start position:0% +Um, +okay. So, now we're just going to plug + + align:start position:0% +okay. So, now we're just going to plug + + + align:start position:0% +okay. So, now we're just going to plug +this in up there. I'll have an x plus d + + align:start position:0% +this in up there. I'll have an x plus d + + + align:start position:0% +this in up there. I'll have an x plus d +up there + + align:start position:0% +up there + + + align:start position:0% +up there +and a log r factor. The x in the x plus + + align:start position:0% +and a log r factor. The x in the x plus + + + align:start position:0% +and a log r factor. The x in the x plus +d gives me this and the d and the x plus + + align:start position:0% +d gives me this and the d and the x plus + + + align:start position:0% +d gives me this and the d and the x plus +d gives me that. It's just algebra. + + align:start position:0% + + + + align:start position:0% + +Okay. Now let's compare this with the + + align:start position:0% +Okay. Now let's compare this with the + + + align:start position:0% +Okay. Now let's compare this with the +theorem we proved last time in finite + + align:start position:0% +theorem we proved last time in finite + + + align:start position:0% +theorem we proved last time in finite +fields. + + align:start position:0% +fields. + + + align:start position:0% +fields. +So theorem one in finite fields said + + align:start position:0% +So theorem one in finite fields said + + + align:start position:0% +So theorem one in finite fields said +that if we had x in fq2 + + align:start position:0% +that if we had x in fq2 + + + align:start position:0% +that if we had x in fq2 +and d in fq + + align:start position:0% +and d in fq + + + align:start position:0% +and d in fq +and s is the maximum + + align:start position:0% +and s is the maximum + + + align:start position:0% +and s is the maximum +theta and d size is pi theta of x. + + align:start position:0% +theta and d size is pi theta of x. + + + align:start position:0% +theta and d size is pi theta of x. +Um + + align:start position:0% +Um + + + align:start position:0% +Um +then + + align:start position:0% +then + + + align:start position:0% +then +either S is around X or D is bounded by + + align:start position:0% +either S is around X or D is bounded by + + + align:start position:0% +either S is around X or D is bounded by +S. + + align:start position:0% + + + + align:start position:0% + +And the numerology is now the same in + + align:start position:0% +And the numerology is now the same in + + + align:start position:0% +And the numerology is now the same in +finite fields or or or if you have balls + + align:start position:0% +finite fields or or or if you have balls + + + align:start position:0% +finite fields or or or if you have balls +with the house space. + + align:start position:0% + + + + align:start position:0% + +Okay. + + align:start position:0% +Okay. + + + align:start position:0% +Okay. +Um so in general the numerology in a lot + + align:start position:0% +Um so in general the numerology in a lot + + + align:start position:0% +Um so in general the numerology in a lot +of things is the same between finite + + align:start position:0% +of things is the same between finite + + + align:start position:0% +of things is the same between finite +fields and balls with housedorf spacing + + align:start position:0% +fields and balls with housedorf spacing + + + align:start position:0% +fields and balls with housedorf spacing +and so now I'll so this was theorem one + + align:start position:0% +and so now I'll so this was theorem one + + + align:start position:0% +and so now I'll so this was theorem one +from last time I'll track through also + + align:start position:0% +from last time I'll track through also + + + align:start position:0% +from last time I'll track through also +theorem two from last time and the + + align:start position:0% +theorem two from last time and the + + + align:start position:0% +theorem two from last time and the +conjecture from last time and we'll see + + align:start position:0% +conjecture from last time and we'll see + + + align:start position:0% +conjecture from last time and we'll see +that they all match up + + align:start position:0% + + + + align:start position:0% + +Okay. + + align:start position:0% +Okay. + + + align:start position:0% +Okay. +So I have + + align:start position:0% + + + + align:start position:0% + +projection theory + + align:start position:0% +projection theory + + + align:start position:0% +projection theory +in FQ2 + + align:start position:0% +in FQ2 + + + align:start position:0% +in FQ2 +versus um in + + align:start position:0% +versus um in + + + align:start position:0% +versus um in +versus unit balls in B2R + + align:start position:0% + + + + align:start position:0% + +and B2R with housed door space. + + align:start position:0% + + + + align:start position:0% + +Okay, so here was theorem two last time + + align:start position:0% +Okay, so here was theorem two last time + + + align:start position:0% +Okay, so here was theorem two last time +in finite fields. + + align:start position:0% +in finite fields. + + + align:start position:0% +in finite fields. +So if we have our finite field setup + + align:start position:0% +So if we have our finite field setup + + + align:start position:0% +So if we have our finite field setup +which is over here + + align:start position:0% + + + + align:start position:0% + +and S is smaller than Q. + + align:start position:0% + + + + align:start position:0% + +Um then conclusion is that the number of + + align:start position:0% +Um then conclusion is that the number of + + + align:start position:0% +Um then conclusion is that the number of +directions is smaller than SQX. + + align:start position:0% + + + + align:start position:0% + +And here's what we'll prove in the real + + align:start position:0% +And here's what we'll prove in the real + + + align:start position:0% +And here's what we'll prove in the real +case correlary to R. So if we have our + + align:start position:0% +case correlary to R. So if we have our + + + align:start position:0% +case correlary to R. So if we have our +setup of the day and X and D are housed + + align:start position:0% +setup of the day and X and D are housed + + + align:start position:0% +setup of the day and X and D are housed +and S is a good bit smaller than R. + + align:start position:0% + + + + align:start position:0% + +Then maybe this needs a little bit more + + align:start position:0% + + + + align:start position:0% + +um than d + + align:start position:0% +um than d + + + align:start position:0% +um than d +smaller than sr /x. + + align:start position:0% + + + + align:start position:0% + +Okay. So I I use this symbol with the + + align:start position:0% +Okay. So I I use this symbol with the + + + align:start position:0% +Okay. So I I use this symbol with the +extra tilda that's hiding something like + + align:start position:0% +extra tilda that's hiding something like + + + align:start position:0% +extra tilda that's hiding something like +a log factor similar to the log factor + + align:start position:0% +a log factor similar to the log factor + + + align:start position:0% +a log factor similar to the log factor +that appeared over here. Like if you if + + align:start position:0% +that appeared over here. Like if you if + + + align:start position:0% +that appeared over here. Like if you if +you compare the real case theorem one + + align:start position:0% +you compare the real case theorem one + + + align:start position:0% +you compare the real case theorem one +and the finite field case we lost an + + align:start position:0% +and the finite field case we lost an + + + align:start position:0% +and the finite field case we lost an +extra log r factor and that h that will + + align:start position:0% +extra log r factor and that h that will + + + align:start position:0% +extra log r factor and that h that will +happen sometimes. Um + + align:start position:0% +happen sometimes. Um + + + align:start position:0% +happen sometimes. Um +so uh notation + + align:start position:0% + + + + align:start position:0% + +a less sum b means + + align:start position:0% +a less sum b means + + + align:start position:0% +a less sum b means +for every epsilon bigger than zero there + + align:start position:0% +for every epsilon bigger than zero there + + + align:start position:0% +for every epsilon bigger than zero there +exists c epsilon. So a is less than or + + align:start position:0% +exists c epsilon. So a is less than or + + + align:start position:0% +exists c epsilon. So a is less than or +equal to c epsilon r the epsilon. + + align:start position:0% + + + + align:start position:0% + +Okay. But if you compare these um Q + + align:start position:0% +Okay. But if you compare these um Q + + + align:start position:0% +Okay. But if you compare these um Q +corresponds to R. + + align:start position:0% +corresponds to R. + + + align:start position:0% +corresponds to R. +That makes sense. There are Q ^2 points + + align:start position:0% +That makes sense. There are Q ^2 points + + + align:start position:0% +That makes sense. There are Q ^2 points +here and there are R squar unit balls + + align:start position:0% +here and there are R squar unit balls + + + align:start position:0% +here and there are R squar unit balls +here. + + align:start position:0% + + + + align:start position:0% + +Um and these basically match up except + + align:start position:0% +Um and these basically match up except + + + align:start position:0% +Um and these basically match up except +that there's a minor sort of loss here. + + align:start position:0% +that there's a minor sort of loss here. + + + align:start position:0% +that there's a minor sort of loss here. +Okay. And so this is this is the forier + + align:start position:0% +Okay. And so this is this is the forier + + + align:start position:0% +Okay. And so this is this is the forier +method that we'll turn to in a little + + align:start position:0% +method that we'll turn to in a little + + + align:start position:0% +method that we'll turn to in a little +bit. Um there is also a conjecture about + + align:start position:0% +bit. Um there is also a conjecture about + + + align:start position:0% +bit. Um there is also a conjecture about +the sharp behavior. + + align:start position:0% +the sharp behavior. + + + align:start position:0% +the sharp behavior. +So conjecture + + align:start position:0% +So conjecture + + + align:start position:0% +So conjecture +if P is prime + + align:start position:0% +if P is prime + + + align:start position:0% +if P is prime +and we have our finite field setup + + align:start position:0% + + + + align:start position:0% + +and S is smaller than the minimum of Q + + align:start position:0% +and S is smaller than the minimum of Q + + + align:start position:0% +and S is smaller than the minimum of Q +and X. So either of these are sort of + + align:start position:0% +and X. So either of these are sort of + + + align:start position:0% +and X. So either of these are sort of +trivial. S is always at most Q and it's + + align:start position:0% +trivial. S is always at most Q and it's + + + align:start position:0% +trivial. S is always at most Q and it's +always at most X. So we're make it less + + align:start position:0% +always at most X. So we're make it less + + + align:start position:0% +always at most X. So we're make it less +than that. So we're sort of in a + + align:start position:0% +than that. So we're sort of in a + + + align:start position:0% +than that. So we're sort of in a +non-trivial range. + + align:start position:0% +non-trivial range. + + + align:start position:0% +non-trivial range. +um then + + align:start position:0% +um then + + + align:start position:0% +um then +b should be bounded by s^2 overx which + + align:start position:0% +b should be bounded by s^2 overx which + + + align:start position:0% +b should be bounded by s^2 overx which +would be sharp if it's true and it + + align:start position:0% +would be sharp if it's true and it + + + align:start position:0% +would be sharp if it's true and it +matches the behavior in an integer grid. + + align:start position:0% +matches the behavior in an integer grid. + + + align:start position:0% +matches the behavior in an integer grid. +Okay, this conjecture has an analog + + align:start position:0% +Okay, this conjecture has an analog + + + align:start position:0% +Okay, this conjecture has an analog +uh over in the real case and the real + + align:start position:0% +uh over in the real case and the real + + + align:start position:0% +uh over in the real case and the real +analog is uh is due to fenberg. It's + + align:start position:0% +analog is uh is due to fenberg. It's + + + align:start position:0% +analog is uh is due to fenberg. It's +called the fenber set conjecture. So it + + align:start position:0% +called the fenber set conjecture. So it + + + align:start position:0% +called the fenber set conjecture. So it +says if we have the setup and X and B + + align:start position:0% +says if we have the setup and X and B + + + align:start position:0% +says if we have the setup and X and B +are housed dorf + + align:start position:0% + + + + align:start position:0% + +um and S is significantly less than the + + align:start position:0% +um and S is significantly less than the + + + align:start position:0% +um and S is significantly less than the +minimum of R and X. So again S is always + + align:start position:0% +minimum of R and X. So again S is always + + + align:start position:0% +minimum of R and X. So again S is always +smaller than R. It's always smaller than + + align:start position:0% +smaller than R. It's always smaller than + + + align:start position:0% +smaller than R. It's always smaller than +X and we're saying it's significantly + + align:start position:0% +X and we're saying it's significantly + + + align:start position:0% +X and we're saying it's significantly +less than that. So it's sort of + + align:start position:0% +less than that. So it's sort of + + + align:start position:0% +less than that. So it's sort of +non-trivial. + + align:start position:0% +non-trivial. + + + align:start position:0% +non-trivial. +um then + + align:start position:0% +um then + + + align:start position:0% +um then +the number of directions would be less + + align:start position:0% +the number of directions would be less + + + align:start position:0% +the number of directions would be less +than tilda tilda s^2 overx. + + align:start position:0% +than tilda tilda s^2 overx. + + + align:start position:0% +than tilda tilda s^2 overx. +You see that these conjectures again + + align:start position:0% +You see that these conjectures again + + + align:start position:0% +You see that these conjectures again +match up. + + align:start position:0% + + + + align:start position:0% + +Cool. + + align:start position:0% +Cool. + + + align:start position:0% +Cool. +Okay. Now I mentioned on the first day + + align:start position:0% +Okay. Now I mentioned on the first day + + + align:start position:0% +Okay. Now I mentioned on the first day +that one of the fundamental thought + + align:start position:0% +that one of the fundamental thought + + + align:start position:0% +that one of the fundamental thought +problems of projection theory recently + + align:start position:0% +problems of projection theory recently + + + align:start position:0% +problems of projection theory recently +had been solved. This is the problem. So + + align:start position:0% +had been solved. This is the problem. So + + + align:start position:0% +had been solved. This is the problem. So +this conjecture has been proven. Um so + + align:start position:0% +this conjecture has been proven. Um so + + + align:start position:0% +this conjecture has been proven. Um so +this is a theorem from 2024 + + align:start position:0% +this is a theorem from 2024 + + + align:start position:0% +this is a theorem from 2024 +of Orpinan + + align:start position:0% +of Orpinan + + + align:start position:0% +of Orpinan +Schmurkin + + align:start position:0% + + + + align:start position:0% + +Ran and Wong + + align:start position:0% +Ran and Wong + + + align:start position:0% +Ran and Wong +conjecture is true. + + align:start position:0% + + + + align:start position:0% + +in the first but finite field is still + + align:start position:0% +in the first but finite field is still + + + align:start position:0% +in the first but finite field is still +open. + + align:start position:0% +open. + + + align:start position:0% +open. +>> Yes, thank you. Yeah, conjecture R is + + align:start position:0% +>> Yes, thank you. Yeah, conjecture R is + + + align:start position:0% +>> Yes, thank you. Yeah, conjecture R is +true. Finite field is still wide open. + + align:start position:0% +true. Finite field is still wide open. + + + align:start position:0% +true. Finite field is still wide open. +Yes. + + align:start position:0% +Yes. + + + align:start position:0% +Yes. +Yes. + + align:start position:0% + + + + align:start position:0% + +Cool. So actually another reason I was + + align:start position:0% +Cool. So actually another reason I was + + + align:start position:0% +Cool. So actually another reason I was +excited to do projection theory this + + align:start position:0% +excited to do projection theory this + + + align:start position:0% +excited to do projection theory this +semester is that a bunch of the + + align:start position:0% +semester is that a bunch of the + + + align:start position:0% +semester is that a bunch of the +architects of the recent developments + + align:start position:0% +architects of the recent developments + + + align:start position:0% +architects of the recent developments +will be visiting. Pablo Mkin is going to + + align:start position:0% +will be visiting. Pablo Mkin is going to + + + align:start position:0% +will be visiting. Pablo Mkin is going to +be here for about a month. He's going to + + align:start position:0% +be here for about a month. He's going to + + + align:start position:0% +be here for about a month. He's going to +talk in the analysis seminar. I might + + align:start position:0% +talk in the analysis seminar. I might + + + align:start position:0% +talk in the analysis seminar. I might +rope him into talking in this class. Um + + align:start position:0% +rope him into talking in this class. Um + + + align:start position:0% +rope him into talking in this class. Um +Kevin Ran is going to visit and give a + + align:start position:0% +Kevin Ran is going to visit and give a + + + align:start position:0% +Kevin Ran is going to visit and give a +talk. Hung will be here at at some + + align:start position:0% +talk. Hung will be here at at some + + + align:start position:0% +talk. Hung will be here at at some +point, although maybe not during + + align:start position:0% +point, although maybe not during + + + align:start position:0% +point, although maybe not during +classes. + + align:start position:0% + + + + align:start position:0% + +Yeah, I'll say let me say something very + + align:start position:0% +Yeah, I'll say let me say something very + + + align:start position:0% +Yeah, I'll say let me say something very +briefly. So these these two conjectures + + align:start position:0% +briefly. So these these two conjectures + + + align:start position:0% +briefly. So these these two conjectures +I presented them as being parallel to + + align:start position:0% +I presented them as being parallel to + + + align:start position:0% +I presented them as being parallel to +each other. I think that's fair. Um and + + align:start position:0% +each other. I think that's fair. Um and + + + align:start position:0% +each other. I think that's fair. Um and +they're both quite difficult. Um this + + align:start position:0% +they're both quite difficult. Um this + + + align:start position:0% +they're both quite difficult. Um this +one people have managed to prove which + + align:start position:0% +one people have managed to prove which + + + align:start position:0% +one people have managed to prove which +is exciting and um and this one is still + + align:start position:0% +is exciting and um and this one is still + + + align:start position:0% +is exciting and um and this one is still +open. So uh the difference is that in + + align:start position:0% +open. So uh the difference is that in + + + align:start position:0% +open. So uh the difference is that in +this problem there are many different + + align:start position:0% +this problem there are many different + + + align:start position:0% +this problem there are many different +scales. We've sort of seen the many + + align:start position:0% +scales. We've sort of seen the many + + + align:start position:0% +scales. We've sort of seen the many +different scales in in what we just did + + align:start position:0% +different scales in in what we just did + + + align:start position:0% +different scales in in what we just did +with double counting. We had to think + + align:start position:0% +with double counting. We had to think + + + align:start position:0% +with double counting. We had to think +about all these different scales and + + align:start position:0% +about all these different scales and + + + align:start position:0% +about all these different scales and +we're going to do it again with the + + align:start position:0% +we're going to do it again with the + + + align:start position:0% +we're going to do it again with the +forier method. So far you might have the + + align:start position:0% +forier method. So far you might have the + + + align:start position:0% +forier method. So far you might have the +impression that these different scales + + align:start position:0% +impression that these different scales + + + align:start position:0% +impression that these different scales +are just a nuisance. They make simple + + align:start position:0% +are just a nuisance. They make simple + + + align:start position:0% +are just a nuisance. They make simple +arguments more complicated and the + + align:start position:0% +arguments more complicated and the + + + align:start position:0% +arguments more complicated and the +expressions longer. Um but but actually + + align:start position:0% +expressions longer. Um but but actually + + + align:start position:0% +expressions longer. Um but but actually +having these many different scales will + + align:start position:0% +having these many different scales will + + + align:start position:0% +having these many different scales will +turn out to be a help. Um so they play a + + align:start position:0% +turn out to be a help. Um so they play a + + + align:start position:0% +turn out to be a help. Um so they play a +key role in the proof of this that + + align:start position:0% + + + + align:start position:0% + +somehow because of all these scales if + + align:start position:0% +somehow because of all these scales if + + + align:start position:0% +somehow because of all these scales if +if if something goes wrong something has + + align:start position:0% +if if something goes wrong something has + + + align:start position:0% +if if something goes wrong something has +to go wrong at many different scales. Um + + align:start position:0% +to go wrong at many different scales. Um + + + align:start position:0% +to go wrong at many different scales. Um +the argument also has different cases + + align:start position:0% +the argument also has different cases + + + align:start position:0% +the argument also has different cases +depending upon whether the sets look + + align:start position:0% +depending upon whether the sets look + + + align:start position:0% +depending upon whether the sets look +like set have spacing like number one or + + align:start position:0% +like set have spacing like number one or + + + align:start position:0% +like set have spacing like number one or +spacing like number two. There are + + align:start position:0% +spacing like number two. There are + + + align:start position:0% +spacing like number two. There are +different things to play with. They're + + align:start position:0% +different things to play with. They're + + + align:start position:0% +different things to play with. They're +both helpful in different ways + + align:start position:0% +both helpful in different ways + + + align:start position:0% +both helpful in different ways +and and none of that structure is + + align:start position:0% +and and none of that structure is + + + align:start position:0% +and and none of that structure is +available here. So So probably + + align:start position:0% +available here. So So probably + + + align:start position:0% +available here. So So probably +completely different ideas would be + + align:start position:0% +completely different ideas would be + + + align:start position:0% +completely different ideas would be +needed. + + align:start position:0% + + + + align:start position:0% + +Okay, good. So the second half of the + + align:start position:0% +Okay, good. So the second half of the + + + align:start position:0% +Okay, good. So the second half of the +class the goal is to do the forier + + align:start position:0% +class the goal is to do the forier + + + align:start position:0% +class the goal is to do the forier +method in the real case and build up + + align:start position:0% +method in the real case and build up + + + align:start position:0% +method in the real case and build up +towards towards doing this. Um let me + + align:start position:0% +towards towards doing this. Um let me + + + align:start position:0% +towards towards doing this. Um let me +remind you first of the main thing we + + align:start position:0% +remind you first of the main thing we + + + align:start position:0% +remind you first of the main thing we +proved using for analysis over finite + + align:start position:0% +proved using for analysis over finite + + + align:start position:0% +proved using for analysis over finite +fields and then we'll set up a version + + align:start position:0% +fields and then we'll set up a version + + + align:start position:0% +fields and then we'll set up a version +over over the rings. + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% + + + + align:start position:0% + +Okay. So part two of the class for a + + align:start position:0% +Okay. So part two of the class for a + + + align:start position:0% +Okay. So part two of the class for a +method. + + align:start position:0% + + + + align:start position:0% + +Um okay so the main lema that we proved + + align:start position:0% +Um okay so the main lema that we proved + + + align:start position:0% +Um okay so the main lema that we proved +over finite fields is like this. + + align:start position:0% +over finite fields is like this. + + + align:start position:0% +over finite fields is like this. +So let's say fancy L is a set of lines + + align:start position:0% +So let's say fancy L is a set of lines + + + align:start position:0% +So let's say fancy L is a set of lines +in + + align:start position:0% +in + + + align:start position:0% +in +FQ^2 + + align:start position:0% +FQ^2 + + + align:start position:0% +FQ^2 +and um F + + align:start position:0% +and um F + + + align:start position:0% +and um F +is a sum over all these lines of the + + align:start position:0% +is a sum over all these lines of the + + + align:start position:0% +is a sum over all these lines of the +characteristic function of the line. + + align:start position:0% + + + + align:start position:0% + +Okay, if that's true, then we can break + + align:start position:0% +Okay, if that's true, then we can break + + + align:start position:0% +Okay, if that's true, then we can break +up f into two pieces. a zero frequency + + align:start position:0% +up f into two pieces. a zero frequency + + + align:start position:0% +up f into two pieces. a zero frequency +piece and a nonzero frequency piece. So + + align:start position:0% +piece and a nonzero frequency piece. So + + + align:start position:0% +piece and a nonzero frequency piece. So +then + + align:start position:0% +then + + + align:start position:0% +then +f is equal to f0 plus f we called it f + + align:start position:0% +f is equal to f0 plus f we called it f + + + align:start position:0% +f is equal to f0 plus f we called it f +high zero frequency high frequency. + + align:start position:0% +high zero frequency high frequency. + + + align:start position:0% +high zero frequency high frequency. +So that + + align:start position:0% +So that + + + align:start position:0% +So that +so the support of f0 hat is just zero. + + align:start position:0% +so the support of f0 hat is just zero. + + + align:start position:0% +so the support of f0 hat is just zero. +In other words, f0 is constant. + + align:start position:0% +In other words, f0 is constant. + + + align:start position:0% +In other words, f0 is constant. +Um and we can find out exactly what the + + align:start position:0% +Um and we can find out exactly what the + + + align:start position:0% +Um and we can find out exactly what the +constant is. And based on that we can + + align:start position:0% +constant is. And based on that we can + + + align:start position:0% +constant is. And based on that we can +say that the L2 norm squared of this is + + align:start position:0% +say that the L2 norm squared of this is + + + align:start position:0% +say that the L2 norm squared of this is +the number of lines squared. + + align:start position:0% +the number of lines squared. + + + align:start position:0% +the number of lines squared. +Then the support of the high frequency + + align:start position:0% +Then the support of the high frequency + + + align:start position:0% +Then the support of the high frequency +part is the complement of zero. + + align:start position:0% + + + + align:start position:0% + +And the high frequency part + + align:start position:0% +And the high frequency part + + + align:start position:0% +And the high frequency part +has an L2 bound. L2 2 is L * Q + + align:start position:0% + + + + align:start position:0% + +right + + align:start position:0% +right + + + align:start position:0% +right +I remember teaching a intro to real + + align:start position:0% +I remember teaching a intro to real + + + align:start position:0% +I remember teaching a intro to real +analysis class once and I and so I I + + align:start position:0% +analysis class once and I and so I I + + + align:start position:0% +analysis class once and I and so I I +tried to answer the question on the + + align:start position:0% +tried to answer the question on the + + + align:start position:0% +tried to answer the question on the +first day what is real analysis so there + + align:start position:0% +first day what is real analysis so there + + + align:start position:0% +first day what is real analysis so there +are several you know there are lots of + + align:start position:0% +are several you know there are lots of + + + align:start position:0% +are several you know there are lots of +different things you might say something + + align:start position:0% +different things you might say something + + + align:start position:0% +different things you might say something +about convergence and infinity or + + align:start position:0% +about convergence and infinity or + + + align:start position:0% +about convergence and infinity or +whatever but another thing I proposed is + + align:start position:0% +whatever but another thing I proposed is + + + align:start position:0% +whatever but another thing I proposed is +um analysis is complicated equals simple + + align:start position:0% +um analysis is complicated equals simple + + + align:start position:0% +um analysis is complicated equals simple +plus small. + + align:start position:0% +plus small. + + + align:start position:0% +plus small. +We study something complicated. The real + + align:start position:0% +We study something complicated. The real + + + align:start position:0% +We study something complicated. The real +analysis point of view is to try to + + align:start position:0% +analysis point of view is to try to + + + align:start position:0% +analysis point of view is to try to +write it as something simple plus + + align:start position:0% +write it as something simple plus + + + align:start position:0% +write it as something simple plus +something small. + + align:start position:0% +something small. + + + align:start position:0% +something small. +So this is our function that maybe we + + align:start position:0% +So this is our function that maybe we + + + align:start position:0% +So this is our function that maybe we +feel is complicated. We don't understand + + align:start position:0% +feel is complicated. We don't understand + + + align:start position:0% +feel is complicated. We don't understand +it that well yet. We wrote it as + + align:start position:0% +it that well yet. We wrote it as + + + align:start position:0% +it that well yet. We wrote it as +something simple. This is a constant + + align:start position:0% +something simple. This is a constant + + + align:start position:0% +something simple. This is a constant +function which makes it quite simpler + + align:start position:0% +function which makes it quite simpler + + + align:start position:0% +function which makes it quite simpler +than a general function. And then this + + align:start position:0% +than a general function. And then this + + + align:start position:0% +than a general function. And then this +bit and the point here is that this is + + align:start position:0% +bit and the point here is that this is + + + align:start position:0% +bit and the point here is that this is +smaller than fot or f. Now that that + + align:start position:0% +smaller than fot or f. Now that that + + + align:start position:0% +smaller than fot or f. Now that that +only becomes true and this only becomes + + align:start position:0% +only becomes true and this only becomes + + + align:start position:0% +only becomes true and this only becomes +at all interesting when the number of + + align:start position:0% +at all interesting when the number of + + + align:start position:0% +at all interesting when the number of +lines is much bigger than Q. But when + + align:start position:0% +lines is much bigger than Q. But when + + + align:start position:0% +lines is much bigger than Q. But when +that h when that happens this L2 norm is + + align:start position:0% +that h when that happens this L2 norm is + + + align:start position:0% +that h when that happens this L2 norm is +much smaller than that L2 norm. So + + align:start position:0% +much smaller than that L2 norm. So + + + align:start position:0% +much smaller than that L2 norm. So +complicated equals simple plus small. + + align:start position:0% +complicated equals simple plus small. + + + align:start position:0% +complicated equals simple plus small. +Okay. So uh so our goal is I will + + align:start position:0% +Okay. So uh so our goal is I will + + + align:start position:0% +Okay. So uh so our goal is I will +describe to you the version of this lema + + align:start position:0% +describe to you the version of this lema + + + align:start position:0% +describe to you the version of this lema +in over the real numbers. + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% + + + + align:start position:0% + +Okay. + + align:start position:0% +Okay. + + + align:start position:0% +Okay. +So instead of a line, so infinitely thin + + align:start position:0% +So instead of a line, so infinitely thin + + + align:start position:0% +So instead of a line, so infinitely thin +line, what we're going to talk about is + + align:start position:0% +line, what we're going to talk about is + + + align:start position:0% +line, what we're going to talk about is +a rectangle or I usually call it a tube. + + align:start position:0% +a rectangle or I usually call it a tube. + + + align:start position:0% +a rectangle or I usually call it a tube. +So capital T for tube is a one by R + + align:start position:0% +So capital T for tube is a one by R + + + align:start position:0% +So capital T for tube is a one by R +rectangle + + align:start position:0% + + + + align:start position:0% + +in the plane + + align:start position:0% +in the plane + + + align:start position:0% +in the plane +in any direction. + + align:start position:0% +in any direction. + + + align:start position:0% +in any direction. +Okay. And so basically we're going to + + align:start position:0% +Okay. And so basically we're going to + + + align:start position:0% +Okay. And so basically we're going to +add up characteristic functions of + + align:start position:0% +add up characteristic functions of + + + align:start position:0% +add up characteristic functions of +rectangles. + + align:start position:0% +rectangles. + + + align:start position:0% +rectangles. +Um but when you do for analysis + + align:start position:0% +Um but when you do for analysis + + + align:start position:0% +Um but when you do for analysis +characteristic functions of rectangles + + align:start position:0% +characteristic functions of rectangles + + + align:start position:0% +characteristic functions of rectangles +or characteristic functions in general + + align:start position:0% +or characteristic functions in general + + + align:start position:0% +or characteristic functions in general +are not super nice because of the + + align:start position:0% +are not super nice because of the + + + align:start position:0% +are not super nice because of the +discontinuous sharp cut offs their 4A + + align:start position:0% +discontinuous sharp cut offs their 4A + + + align:start position:0% +discontinuous sharp cut offs their 4A +transforms are not very well behaved. So + + align:start position:0% +transforms are not very well behaved. So + + + align:start position:0% +transforms are not very well behaved. So +what we often do is we work with a + + align:start position:0% +what we often do is we work with a + + + align:start position:0% +what we often do is we work with a +smoothed approximation of the + + align:start position:0% +smoothed approximation of the + + + align:start position:0% +smoothed approximation of the +characteristic function. + + align:start position:0% +characteristic function. + + + align:start position:0% +characteristic function. +So + + align:start position:0% +So + + + align:start position:0% +So +C subt is a smooth + + align:start position:0% +C subt is a smooth + + + align:start position:0% +C subt is a smooth +approximation + + align:start position:0% + + + + align:start position:0% + +of the characteristic function of T. + + align:start position:0% +of the characteristic function of T. + + + align:start position:0% +of the characteristic function of T. +Okay. Um so another thing about this + + align:start position:0% +Okay. Um so another thing about this + + + align:start position:0% +Okay. Um so another thing about this +step of doing for analysis on R2 instead + + align:start position:0% +step of doing for analysis on R2 instead + + + align:start position:0% +step of doing for analysis on R2 instead +of finite fields is that certain things + + align:start position:0% +of finite fields is that certain things + + + align:start position:0% +of finite fields is that certain things +are a little bit messy. for example, + + align:start position:0% +are a little bit messy. for example, + + + align:start position:0% +are a little bit messy. for example, +it's a little bit messy to write down + + align:start position:0% +it's a little bit messy to write down + + + align:start position:0% +it's a little bit messy to write down +the formula for C subt. + + align:start position:0% +the formula for C subt. + + + align:start position:0% +the formula for C subt. +Um, so I'm going to try the approach of + + align:start position:0% +Um, so I'm going to try the approach of + + + align:start position:0% +Um, so I'm going to try the approach of +not doing the messy details in class. So + + align:start position:0% +not doing the messy details in class. So + + + align:start position:0% +not doing the messy details in class. So +in class I'll give you an overview and + + align:start position:0% +in class I'll give you an overview and + + + align:start position:0% +in class I'll give you an overview and +then on the homework, uh, I'll do all of + + align:start position:0% +then on the homework, uh, I'll do all of + + + align:start position:0% +then on the homework, uh, I'll do all of +the details and and and you can check + + align:start position:0% +the details and and and you can check + + + align:start position:0% +the details and and and you can check +the things and make sure you understand + + align:start position:0% +the things and make sure you understand + + + align:start position:0% +the things and make sure you understand +how it works. + + align:start position:0% +how it works. + + + align:start position:0% +how it works. +And uh and I do that partly because I + + align:start position:0% +And uh and I do that partly because I + + + align:start position:0% +And uh and I do that partly because I +feel like sometimes the messy details + + align:start position:0% +feel like sometimes the messy details + + + align:start position:0% +feel like sometimes the messy details +obscure sort of the main trajectory of + + align:start position:0% +obscure sort of the main trajectory of + + + align:start position:0% +obscure sort of the main trajectory of +what we want to do. It's good to sort of + + align:start position:0% +what we want to do. It's good to sort of + + + align:start position:0% +what we want to do. It's good to sort of +first learn what you want to do and then + + align:start position:0% +first learn what you want to do and then + + + align:start position:0% +first learn what you want to do and then +um once you know where you're trying to + + align:start position:0% +um once you know where you're trying to + + + align:start position:0% +um once you know where you're trying to +go, fill in all the little steps to get + + align:start position:0% +go, fill in all the little steps to get + + + align:start position:0% +go, fill in all the little steps to get +there. + + align:start position:0% +there. + + + align:start position:0% +there. +Okay. So for this class, I won't say + + align:start position:0% +Okay. So for this class, I won't say + + + align:start position:0% +Okay. So for this class, I won't say +anything more precise than C subt is a + + align:start position:0% +anything more precise than C subt is a + + + align:start position:0% +anything more precise than C subt is a +smooth approximation of the + + align:start position:0% +smooth approximation of the + + + align:start position:0% +smooth approximation of the +characteristic function of T. + + align:start position:0% +characteristic function of T. + + + align:start position:0% +characteristic function of T. +Okay. So now here is our + + align:start position:0% +Okay. So now here is our + + + align:start position:0% +Okay. So now here is our +um main lema + + align:start position:0% +um main lema + + + align:start position:0% +um main lema +in the real case. + + align:start position:0% +in the real case. + + + align:start position:0% +in the real case. +Okay. So instead of L is a set of lines, + + align:start position:0% +Okay. So instead of L is a set of lines, + + + align:start position:0% +Okay. So instead of L is a set of lines, +T is a set of 1 by R rectangles + + align:start position:0% +T is a set of 1 by R rectangles + + + align:start position:0% +T is a set of 1 by R rectangles +in the plane R2. + + align:start position:0% +in the plane R2. + + + align:start position:0% +in the plane R2. +And then f is the sum over all the + + align:start position:0% +And then f is the sum over all the + + + align:start position:0% +And then f is the sum over all the +rectangles of this smooth characteristic + + align:start position:0% +rectangles of this smooth characteristic + + + align:start position:0% +rectangles of this smooth characteristic +function. And that plays the role of the + + align:start position:0% +function. And that plays the role of the + + + align:start position:0% +function. And that plays the role of the +function f up there. + + align:start position:0% +function f up there. + + + align:start position:0% +function f up there. +Okay. And then we're going to break this + + align:start position:0% +Okay. And then we're going to break this + + + align:start position:0% +Okay. And then we're going to break this +function up into pieces. There are going + + align:start position:0% +function up into pieces. There are going + + + align:start position:0% +function up into pieces. There are going +to be sort of low frequency pieces that + + align:start position:0% +to be sort of low frequency pieces that + + + align:start position:0% +to be sort of low frequency pieces that +have the advantage of being kind of + + align:start position:0% +have the advantage of being kind of + + + align:start position:0% +have the advantage of being kind of +constant and there are going to be some + + align:start position:0% +constant and there are going to be some + + + align:start position:0% +constant and there are going to be some +high frequency pieces that have the + + align:start position:0% +high frequency pieces that have the + + + align:start position:0% +high frequency pieces that have the +advantage of being small. + + align:start position:0% +advantage of being small. + + + align:start position:0% +advantage of being small. +Uh but the difference between the real + + align:start position:0% +Uh but the difference between the real + + + align:start position:0% +Uh but the difference between the real +world and and FQ is that in FQ there are + + align:start position:0% +world and and FQ is that in FQ there are + + + align:start position:0% +world and and FQ is that in FQ there are +only two kinds of frequencies. There was + + align:start position:0% +only two kinds of frequencies. There was + + + align:start position:0% +only two kinds of frequencies. There was +zero and not zero. Um but uh in in the + + align:start position:0% +zero and not zero. Um but uh in in the + + + align:start position:0% +zero and not zero. Um but uh in in the +reals there are a lot of frequencies. + + align:start position:0% +reals there are a lot of frequencies. + + + align:start position:0% +reals there are a lot of frequencies. +There's large, medium, small, very small + + align:start position:0% +There's large, medium, small, very small + + + align:start position:0% +There's large, medium, small, very small +and all of those are they're each going + + align:start position:0% +and all of those are they're each going + + + align:start position:0% +and all of those are they're each going +to to to be there. Okay. So instead of + + align:start position:0% +to to to be there. Okay. So instead of + + + align:start position:0% +to to to be there. Okay. So instead of +having two pieces, we will have many + + align:start position:0% +having two pieces, we will have many + + + align:start position:0% +having two pieces, we will have many +pieces. + + align:start position:0% + + + + align:start position:0% + +So f is going to be the sum of f little + + align:start position:0% +So f is going to be the sum of f little + + + align:start position:0% +So f is going to be the sum of f little +r little r goes from one up to capital r + + align:start position:0% +r little r goes from one up to capital r + + + align:start position:0% +r little r goes from one up to capital r +and is diatic just like in theorem one. + + align:start position:0% +and is diatic just like in theorem one. + + + align:start position:0% +and is diatic just like in theorem one. +So we'll have log of r many pieces and + + align:start position:0% +So we'll have log of r many pieces and + + + align:start position:0% +So we'll have log of r many pieces and +these are the different scales of the + + align:start position:0% +these are the different scales of the + + + align:start position:0% +these are the different scales of the +frequencies. + + align:start position:0% +frequencies. + + + align:start position:0% +frequencies. +Okay. Uh we'll do this so that + + align:start position:0% +Okay. Uh we'll do this so that + + + align:start position:0% +Okay. Uh we'll do this so that +the support + + align:start position:0% +the support + + + align:start position:0% +the support +of fr hat + + align:start position:0% +of fr hat + + + align:start position:0% +of fr hat +is contained in the ball of radius one + + align:start position:0% +is contained in the ball of radius one + + + align:start position:0% +is contained in the ball of radius one +over little r. So that's the frequency + + align:start position:0% +over little r. So that's the frequency + + + align:start position:0% +over little r. So that's the frequency +information + + align:start position:0% + + + + align:start position:0% + +and um we will say something about the + + align:start position:0% +and um we will say something about the + + + align:start position:0% +and um we will say something about the +L2 norm. + + align:start position:0% + + + + align:start position:0% + +Okay. + + align:start position:0% +Okay. + + + align:start position:0% +Okay. +Now, um, our bounds on the L2 norm + + align:start position:0% +Now, um, our bounds on the L2 norm + + + align:start position:0% +Now, um, our bounds on the L2 norm +before only depended on how many lines + + align:start position:0% +before only depended on how many lines + + + align:start position:0% +before only depended on how many lines +there were, not about how the lines were + + align:start position:0% +there were, not about how the lines were + + + align:start position:0% +there were, not about how the lines were +arranged. Uh, but that won't be quite + + align:start position:0% +arranged. Uh, but that won't be quite + + + align:start position:0% +arranged. Uh, but that won't be quite +true anymore. Like, like we've seen in + + align:start position:0% +true anymore. Like, like we've seen in + + + align:start position:0% +true anymore. Like, like we've seen in +other places, it will matter how these + + align:start position:0% +other places, it will matter how these + + + align:start position:0% +other places, it will matter how these +tubes are clumped. So, if you have many + + align:start position:0% +tubes are clumped. So, if you have many + + + align:start position:0% +tubes are clumped. So, if you have many +tubes that are clumped together inside + + align:start position:0% +tubes that are clumped together inside + + + align:start position:0% +tubes that are clumped together inside +of a um Yeah. Okay. So, let me let me + + align:start position:0% +of a um Yeah. Okay. So, let me let me + + + align:start position:0% +of a um Yeah. Okay. So, let me let me +put the other part of the definition. So + + align:start position:0% +put the other part of the definition. So + + + align:start position:0% +put the other part of the definition. So +n subr of t is the maximum over tilda + + align:start position:0% +n subr of t is the maximum over tilda + + + align:start position:0% +n subr of t is the maximum over tilda +which is like a two little r by two big + + align:start position:0% +which is like a two little r by two big + + + align:start position:0% +which is like a two little r by two big +r rectangle + + align:start position:0% +r rectangle + + + align:start position:0% +r rectangle +of the number of t in our set of t that + + align:start position:0% +of the number of t in our set of t that + + + align:start position:0% +of the number of t in our set of t that +are so that t is contained in t tilda. + + align:start position:0% +are so that t is contained in t tilda. + + + align:start position:0% +are so that t is contained in t tilda. +So here's a picture. + + align:start position:0% +So here's a picture. + + + align:start position:0% +So here's a picture. +So here's tilda. + + align:start position:0% +So here's tilda. + + + align:start position:0% +So here's tilda. +This axis is little r basically and this + + align:start position:0% +This axis is little r basically and this + + + align:start position:0% +This axis is little r basically and this +axis is big r basically. Maybe it's good + + align:start position:0% +axis is big r basically. Maybe it's good + + + align:start position:0% +axis is big r basically. Maybe it's good +to put two big R. Um, and inside of here + + align:start position:0% +to put two big R. Um, and inside of here + + + align:start position:0% +to put two big R. Um, and inside of here +there may be a bunch of R twos. + + align:start position:0% + + + + align:start position:0% + +So just like uh oh and I I guess to be + + align:start position:0% +So just like uh oh and I I guess to be + + + align:start position:0% +So just like uh oh and I I guess to be +consistent with before I should actually + + align:start position:0% +consistent with before I should actually + + + align:start position:0% +consistent with before I should actually +do this. + + align:start position:0% + + + + align:start position:0% + +So n subx of r measured whether many of + + align:start position:0% +So n subx of r measured whether many of + + + align:start position:0% +So n subx of r measured whether many of +the balls in x were clumped together and + + align:start position:0% +the balls in x were clumped together and + + + align:start position:0% +the balls in x were clumped together and +n subt of r measures whether many of the + + align:start position:0% +n subt of r measures whether many of the + + + align:start position:0% +n subt of r measures whether many of the +tubes of t are clumped together. + + align:start position:0% +tubes of t are clumped together. + + + align:start position:0% +tubes of t are clumped together. +Okay. So the bound will depend on that + + align:start position:0% +Okay. So the bound will depend on that + + + align:start position:0% +Okay. So the bound will depend on that +thing and it is + + align:start position:0% +thing and it is + + + align:start position:0% +thing and it is +formula is + + align:start position:0% + + + + align:start position:0% + +okay. + + align:start position:0% +okay. + + + align:start position:0% +okay. +n subt of little r + + align:start position:0% +n subt of little r + + + align:start position:0% +n subt of little r +um times the number of tubes + + align:start position:0% +um times the number of tubes + + + align:start position:0% +um times the number of tubes +time little r inverse time big. + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% + + + + align:start position:0% + +Okay, so you can see that I don't + + align:start position:0% +Okay, so you can see that I don't + + + align:start position:0% +Okay, so you can see that I don't +remember this formula that well. Um but + + align:start position:0% +remember this formula that well. Um but + + + align:start position:0% +remember this formula that well. Um but +one thing to notice about it is that as + + align:start position:0% +one thing to notice about it is that as + + + align:start position:0% +one thing to notice about it is that as +as this number gets bigger then our + + align:start position:0% +as this number gets bigger then our + + + align:start position:0% +as this number gets bigger then our +bound for this gets bigger. + + align:start position:0% +bound for this gets bigger. + + + align:start position:0% +bound for this gets bigger. +Um I also claim that this tracks with + + align:start position:0% +Um I also claim that this tracks with + + + align:start position:0% +Um I also claim that this tracks with +the finite field case. Um so if you plug + + align:start position:0% +the finite field case. Um so if you plug + + + align:start position:0% +the finite field case. Um so if you plug +in little r equals 1 that's the highest + + align:start position:0% +in little r equals 1 that's the highest + + + align:start position:0% +in little r equals 1 that's the highest +frequency part. Um n subt of one is is + + align:start position:0% +frequency part. Um n subt of one is is + + + align:start position:0% +frequency part. Um n subt of one is is +going to be just one. If if the tubes + + align:start position:0% +going to be just one. If if the tubes + + + align:start position:0% +going to be just one. If if the tubes +are disjoint then then or the tubes are + + align:start position:0% +are disjoint then then or the tubes are + + + align:start position:0% +are disjoint then then or the tubes are +distinct then anyway um uh so then if + + align:start position:0% +distinct then anyway um uh so then if + + + align:start position:0% +distinct then anyway um uh so then if +you plug in little r equals 1 this + + align:start position:0% +you plug in little r equals 1 this + + + align:start position:0% +you plug in little r equals 1 this +number will match with the high + + align:start position:0% +number will match with the high + + + align:start position:0% +number will match with the high +frequency case. And if you plug in + + align:start position:0% +frequency case. And if you plug in + + + align:start position:0% +frequency case. And if you plug in +little r equals big r, then this will + + align:start position:0% +little r equals big r, then this will + + + align:start position:0% +little r equals big r, then this will +match with the zero frequency case. But + + align:start position:0% +match with the zero frequency case. But + + + align:start position:0% +match with the zero frequency case. But +now we also have all this in between + + align:start position:0% +now we also have all this in between + + + align:start position:0% +now we also have all this in between +stuff. + + align:start position:0% + + + + align:start position:0% + +Okay, + + align:start position:0% +Okay, + + + align:start position:0% +Okay, +any questions or comments about this + + align:start position:0% +any questions or comments about this + + + align:start position:0% +any questions or comments about this +statement? + + align:start position:0% +statement? + + + align:start position:0% +statement? +So I'm going to do a proof sketch. + + align:start position:0% + + + + align:start position:0% + +proof sketch main are details on + + align:start position:0% +proof sketch main are details on + + + align:start position:0% +proof sketch main are details on +homework two. + + align:start position:0% + + + + align:start position:0% + +How's homework one going? + + align:start position:0% + + + + align:start position:0% + +If you're interested, there are office + + align:start position:0% +If you're interested, there are office + + + align:start position:0% +If you're interested, there are office +hours after class today and after class + + align:start position:0% +hours after class today and after class + + + align:start position:0% +hours after class today and after class +on Thursday. + + align:start position:0% + + + + align:start position:0% + +Okay. Um, + + align:start position:0% + + + + align:start position:0% + +okay. There's a fora analysis proof and + + align:start position:0% +okay. There's a fora analysis proof and + + + align:start position:0% +okay. There's a fora analysis proof and +an important character is well we're + + align:start position:0% +an important character is well we're + + + align:start position:0% +an important character is well we're +take the fora transform of each of these + + align:start position:0% +take the fora transform of each of these + + + align:start position:0% +take the fora transform of each of these +ct hat and the support of ct hat is + + align:start position:0% +ct hat and the support of ct hat is + + + align:start position:0% +ct hat and the support of ct hat is +going to be contained in t star where t + + align:start position:0% +going to be contained in t star where t + + + align:start position:0% +going to be contained in t star where t +star is defined as follows + + align:start position:0% +star is defined as follows + + + align:start position:0% +star is defined as follows +it's the set of c and r2 + + align:start position:0% +it's the set of c and r2 + + + align:start position:0% +it's the set of c and r2 +so that + + align:start position:0% +so that + + + align:start position:0% +so that +the dotproduct x1 - x2 c is at most has + + align:start position:0% +the dotproduct x1 - x2 c is at most has + + + align:start position:0% +the dotproduct x1 - x2 c is at most has +norm at most one for any x1 and x2 in t. + + align:start position:0% +norm at most one for any x1 and x2 in t. + + + align:start position:0% +norm at most one for any x1 and x2 in t. +Um here's a picture. + + align:start position:0% +Um here's a picture. + + + align:start position:0% +Um here's a picture. +So in x space here is our tube t and I + + align:start position:0% +So in x space here is our tube t and I + + + align:start position:0% +So in x space here is our tube t and I +take a couple of points in it x1 and x2 + + align:start position:0% +take a couple of points in it x1 and x2 + + + align:start position:0% +take a couple of points in it x1 and x2 +and so so our c is going to have a small + + align:start position:0% +and so so our c is going to have a small + + + align:start position:0% +and so so our c is going to have a small +dotproduct with any vector like that. + + align:start position:0% +dotproduct with any vector like that. + + + align:start position:0% +dotproduct with any vector like that. +And so um okay the dimensions of this t + + align:start position:0% +And so um okay the dimensions of this t + + + align:start position:0% +And so um okay the dimensions of this t +are this is one and this is r. + + align:start position:0% +are this is one and this is r. + + + align:start position:0% +are this is one and this is r. +Okay. Now in csp space um t star is + + align:start position:0% +Okay. Now in csp space um t star is + + + align:start position:0% +Okay. Now in csp space um t star is +going to be sort of perpendicular to t. + + align:start position:0% +going to be sort of perpendicular to t. + + + align:start position:0% +going to be sort of perpendicular to t. +There's t star and it has length one and + + align:start position:0% +There's t star and it has length one and + + + align:start position:0% +There's t star and it has length one and +width like 1 / r. + + align:start position:0% + + + + align:start position:0% + +So geometrically the idea is that if I + + align:start position:0% +So geometrically the idea is that if I + + + align:start position:0% +So geometrically the idea is that if I +take my vector here and my vector there, + + align:start position:0% +take my vector here and my vector there, + + + align:start position:0% +take my vector here and my vector there, +the long component of this one has size + + align:start position:0% +the long component of this one has size + + + align:start position:0% +the long component of this one has size +R and it gets paired with the short + + align:start position:0% +R and it gets paired with the short + + + align:start position:0% +R and it gets paired with the short +component of that one which has size one + + align:start position:0% +component of that one which has size one + + + align:start position:0% +component of that one which has size one +over R which gives me around one and the + + align:start position:0% +over R which gives me around one and the + + + align:start position:0% +over R which gives me around one and the +two short component the short component + + align:start position:0% +two short component the short component + + + align:start position:0% +two short component the short component +here has size one which gets paired with + + align:start position:0% +here has size one which gets paired with + + + align:start position:0% +here has size one which gets paired with +the long component here which has size + + align:start position:0% +the long component here which has size + + + align:start position:0% +the long component here which has size +one. + + align:start position:0% + + + + align:start position:0% + +Okay. Um and this is analogous to the + + align:start position:0% +Okay. Um and this is analogous to the + + + align:start position:0% +Okay. Um and this is analogous to the +lema we had in the finite field case + + align:start position:0% +lema we had in the finite field case + + + align:start position:0% +lema we had in the finite field case +that that the characteristic function of + + align:start position:0% +that that the characteristic function of + + + align:start position:0% +that that the characteristic function of +a line hat was supported in the line per + + align:start position:0% +a line hat was supported in the line per + + + align:start position:0% +a line hat was supported in the line per +which is like star. + + align:start position:0% + + + + align:start position:0% + +Okay. + + align:start position:0% +Okay. + + + align:start position:0% +Okay. +Um + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +so that's the first important ingredient + + align:start position:0% +so that's the first important ingredient + + + align:start position:0% +so that's the first important ingredient +where the 4A transforms live and I guess + + align:start position:0% +where the 4A transforms live and I guess + + + align:start position:0% +where the 4A transforms live and I guess +you're doing the homework now where + + align:start position:0% +you're doing the homework now where + + + align:start position:0% +you're doing the homework now where +you're checking what what line hat looks + + align:start position:0% +you're checking what what line hat looks + + + align:start position:0% +you're checking what what line hat looks +like and then in the next homework + + align:start position:0% +like and then in the next homework + + + align:start position:0% +like and then in the next homework +you'll check what ct hat looks like and + + align:start position:0% +you'll check what ct hat looks like and + + + align:start position:0% +you'll check what ct hat looks like and +you'll see it supported like this. + + align:start position:0% + + + + align:start position:0% + +Okay. So now I'll tell you who F subr + + align:start position:0% +Okay. So now I'll tell you who F subr + + + align:start position:0% +Okay. So now I'll tell you who F subr +is. Um + + align:start position:0% +is. Um + + + align:start position:0% +is. Um +so let's next do so the f subr comes + + align:start position:0% +so let's next do so the f subr comes + + + align:start position:0% +so let's next do so the f subr comes +from from littlewood paley theory where + + align:start position:0% +from from littlewood paley theory where + + + align:start position:0% +from from littlewood paley theory where +you can take any function and you can + + align:start position:0% +you can take any function and you can + + + align:start position:0% +you can take any function and you can +break its frequencies into diatic pieces + + align:start position:0% +break its frequencies into diatic pieces + + + align:start position:0% +break its frequencies into diatic pieces +the little wood pale pieces. That's what + + align:start position:0% +the little wood pale pieces. That's what + + + align:start position:0% +the little wood pale pieces. That's what +we're doing here. + + align:start position:0% + + + + align:start position:0% + +Okay. So, + + align:start position:0% + + + + align:start position:0% + +so little wood pale decomposition. + + align:start position:0% + + + + align:start position:0% + +So, I'm going to write one as a sum on + + align:start position:0% +So, I'm going to write one as a sum on + + + align:start position:0% +So, I'm going to write one as a sum on +my diatic little rs + + align:start position:0% +my diatic little rs + + + align:start position:0% +my diatic little rs +of ad r of c. So this is a a partition + + align:start position:0% +of ad r of c. So this is a a partition + + + align:start position:0% +of ad r of c. So this is a a partition +of unity on in 4A space. It's a + + align:start position:0% +of unity on in 4A space. It's a + + + align:start position:0% +of unity on in 4A space. It's a +partition of unity. So these are all + + align:start position:0% +partition of unity. So these are all + + + align:start position:0% +partition of unity. So these are all +positive + + align:start position:0% +positive + + + align:start position:0% +positive +and um the support + + align:start position:0% +and um the support + + + align:start position:0% +and um the support +of A to R is contained in in an annulus + + align:start position:0% +of A to R is contained in in an annulus + + + align:start position:0% +of A to R is contained in in an annulus +where the norm of C is at most 1 / R and + + align:start position:0% +where the norm of C is at most 1 / R and + + + align:start position:0% +where the norm of C is at most 1 / R and +at least 1 / 10R. + + align:start position:0% +at least 1 / 10R. + + + align:start position:0% +at least 1 / 10R. +And that's true for R strictly between 1 + + align:start position:0% +And that's true for R strictly between 1 + + + align:start position:0% +And that's true for R strictly between 1 +and R. And at the end points we need to + + align:start position:0% +and R. And at the end points we need to + + + align:start position:0% +and R. And at the end points we need to +have not just an annulus but something a + + align:start position:0% +have not just an annulus but something a + + + align:start position:0% +have not just an annulus but something a +little bit bigger to cover all the + + align:start position:0% +little bit bigger to cover all the + + + align:start position:0% +little bit bigger to cover all the +frequencies. So the support + + align:start position:0% +frequencies. So the support + + + align:start position:0% +frequencies. So the support +of ADA capital R + + align:start position:0% +of ADA capital R + + + align:start position:0% +of ADA capital R +is contained in the ball of radius 1 / R + + align:start position:0% +is contained in the ball of radius 1 / R + + + align:start position:0% +is contained in the ball of radius 1 / R +and the support + + align:start position:0% +and the support + + + align:start position:0% +and the support +of ADA1 + + align:start position:0% +of ADA1 + + + align:start position:0% +of ADA1 +is contained in the set of C where the + + align:start position:0% +is contained in the set of C where the + + + align:start position:0% +is contained in the set of C where the +norm of C is bigger than 110. + + align:start position:0% + + + + align:start position:0% + +All right. Oh, I guess one maybe I + + align:start position:0% +All right. Oh, I guess one maybe I + + + align:start position:0% +All right. Oh, I guess one maybe I +should mention one one thing that we see + + align:start position:0% +should mention one one thing that we see + + + align:start position:0% +should mention one one thing that we see +from this + + align:start position:0% +from this + + + align:start position:0% +from this +is that the support of f hat is + + align:start position:0% +is that the support of f hat is + + + align:start position:0% +is that the support of f hat is +contained in the unit ball because every + + align:start position:0% +contained in the unit ball because every + + + align:start position:0% +contained in the unit ball because every +t star is in is in the unit ball. + + align:start position:0% + + + + align:start position:0% + +Okay. So now I can say who f_sub_r is. + + align:start position:0% +Okay. So now I can say who f_sub_r is. + + + align:start position:0% +Okay. So now I can say who f_sub_r is. +So f is just taking f and taking + + align:start position:0% +So f is just taking f and taking + + + align:start position:0% +So f is just taking f and taking +multiplying on the frequency side by 8 + + align:start position:0% +multiplying on the frequency side by 8 + + + align:start position:0% +multiplying on the frequency side by 8 +r. So I take fhat I multiply it by a r + + align:start position:0% +r. So I take fhat I multiply it by a r + + + align:start position:0% +r. So I take fhat I multiply it by a r +and I take the 4 a transform back. + + align:start position:0% +and I take the 4 a transform back. + + + align:start position:0% +and I take the 4 a transform back. +So this is also equal to f involved with + + align:start position:0% +So this is also equal to f involved with + + + align:start position:0% +So this is also equal to f involved with +a to r inverse 4 a transform. + + align:start position:0% +a to r inverse 4 a transform. + + + align:start position:0% +a to r inverse 4 a transform. +Okay. And because this is a partition of + + align:start position:0% +Okay. And because this is a partition of + + + align:start position:0% +Okay. And because this is a partition of +unity + + align:start position:0% + + + + align:start position:0% + +that tells me that f is indeed the sum + + align:start position:0% +that tells me that f is indeed the sum + + + align:start position:0% +that tells me that f is indeed the sum +over r of fr. + + align:start position:0% +over r of fr. + + + align:start position:0% +over r of fr. +So that so we can check off our first + + align:start position:0% +So that so we can check off our first + + + align:start position:0% +So that so we can check off our first +conclusion. + + align:start position:0% +conclusion. + + + align:start position:0% +conclusion. +Um and from this formula this here is + + align:start position:0% +Um and from this formula this here is + + + align:start position:0% +Um and from this formula this here is +the for transform of FR hat + + align:start position:0% + + + + align:start position:0% + +is a R * Fhat and that tells us that the + + align:start position:0% +is a R * Fhat and that tells us that the + + + align:start position:0% +is a R * Fhat and that tells us that the +support of FR hat is contained in the + + align:start position:0% +support of FR hat is contained in the + + + align:start position:0% +support of FR hat is contained in the +ball of radius 1 / R. So we can check + + align:start position:0% +ball of radius 1 / R. So we can check + + + align:start position:0% +ball of radius 1 / R. So we can check +off that part of the conclusion. + + align:start position:0% +off that part of the conclusion. + + + align:start position:0% +off that part of the conclusion. +And then the difficult and interesting + + align:start position:0% +And then the difficult and interesting + + + align:start position:0% +And then the difficult and interesting +part will be to figure out the L2 norm + + align:start position:0% +part will be to figure out the L2 norm + + + align:start position:0% +part will be to figure out the L2 norm +of each of these pieces FR. + + align:start position:0% + + + + align:start position:0% + +Okay. Um now this operation of + + align:start position:0% +Okay. Um now this operation of + + + align:start position:0% +Okay. Um now this operation of +localizing frequencies to to an annulus + + align:start position:0% +localizing frequencies to to an annulus + + + align:start position:0% +localizing frequencies to to an annulus +around 1 / R you can do it with any + + align:start position:0% +around 1 / R you can do it with any + + + align:start position:0% +around 1 / R you can do it with any +function not just with f. So you can + + align:start position:0% +function not just with f. So you can + + + align:start position:0% +function not just with f. So you can +also do it with each of the ct one at a + + align:start position:0% +also do it with each of the ct one at a + + + align:start position:0% +also do it with each of the ct one at a +time. So ct comma r would be I take ct + + align:start position:0% +time. So ct comma r would be I take ct + + + align:start position:0% +time. So ct comma r would be I take ct +hat I multiply it by a to r I take the + + align:start position:0% +hat I multiply it by a to r I take the + + + align:start position:0% +hat I multiply it by a to r I take the +for a transform back and so f is the sum + + align:start position:0% +for a transform back and so f is the sum + + + align:start position:0% +for a transform back and so f is the sum +over all the t in my set of tubes of ct. + + align:start position:0% + + + + align:start position:0% + +Okay. + + align:start position:0% +Okay. + + + align:start position:0% +Okay. +So the next thing I'd like to do is to + + align:start position:0% +So the next thing I'd like to do is to + + + align:start position:0% +So the next thing I'd like to do is to +visualize together this function a to r + + align:start position:0% +visualize together this function a to r + + + align:start position:0% +visualize together this function a to r +check and this function ctr + + align:start position:0% + + + + align:start position:0% + +do a visual + + align:start position:0% +do a visual + + + align:start position:0% +do a visual +of ad r check um and ctr. + + align:start position:0% + + + + align:start position:0% + +Okay, so the function A to R itself A to + + align:start position:0% +Okay, so the function A to R itself A to + + + align:start position:0% +Okay, so the function A to R itself A to +R of C that's around one on the annulus + + align:start position:0% +R of C that's around one on the annulus + + + align:start position:0% +R of C that's around one on the annulus +of size 1 / little R. + + align:start position:0% +of size 1 / little R. + + + align:start position:0% +of size 1 / little R. +So when I take its inverse for a + + align:start position:0% +So when I take its inverse for a + + + align:start position:0% +So when I take its inverse for a +transform + + align:start position:0% +transform + + + align:start position:0% +transform +um a to r check of x + + align:start position:0% +um a to r check of x + + + align:start position:0% +um a to r check of x +will be around + + align:start position:0% +will be around + + + align:start position:0% +will be around +it'll be around um 1 / r 2 + + align:start position:0% +it'll be around um 1 / r 2 + + + align:start position:0% +it'll be around um 1 / r 2 +of most of x less than r. + + align:start position:0% +of most of x less than r. + + + align:start position:0% +of most of x less than r. +So the you know the biggest this could + + align:start position:0% +So the you know the biggest this could + + + align:start position:0% +So the you know the biggest this could +possibly be is integrating this would be + + align:start position:0% +possibly be is integrating this would be + + + align:start position:0% +possibly be is integrating this would be +the area of this annulus which is 1 / + + align:start position:0% +the area of this annulus which is 1 / + + + align:start position:0% +the area of this annulus which is 1 / +r^2. + + align:start position:0% +r^2. + + + align:start position:0% +r^2. +Um and then because this is smooth once + + align:start position:0% +Um and then because this is smooth once + + + align:start position:0% +Um and then because this is smooth once +I look at x's that are significantly + + align:start position:0% +I look at x's that are significantly + + + align:start position:0% +I look at x's that are significantly +bigger than r I start to get a lot of + + align:start position:0% +bigger than r I start to get a lot of + + + align:start position:0% +bigger than r I start to get a lot of +cancellation in the integral and let me + + align:start position:0% +cancellation in the integral and let me + + + align:start position:0% +cancellation in the integral and let me +write down the formula for this. So a to + + align:start position:0% +write down the formula for this. So a to + + + align:start position:0% +write down the formula for this. So a to +r check of x is the integral e to the ix + + align:start position:0% +r check of x is the integral e to the ix + + + align:start position:0% +r check of x is the integral e to the ix +a r of c dx c. + + align:start position:0% +a r of c dx c. + + + align:start position:0% +a r of c dx c. +So if x is smaller than r, there's no + + align:start position:0% +So if x is smaller than r, there's no + + + align:start position:0% +So if x is smaller than r, there's no +significant cancellation in this + + align:start position:0% +significant cancellation in this + + + align:start position:0% +significant cancellation in this +integral because the c is around 1 / r. + + align:start position:0% +integral because the c is around 1 / r. + + + align:start position:0% +integral because the c is around 1 / r. +Um but then when x is bigger than r, + + align:start position:0% +Um but then when x is bigger than r, + + + align:start position:0% +Um but then when x is bigger than r, +there starts to be cancellation in this + + align:start position:0% +there starts to be cancellation in this + + + align:start position:0% +there starts to be cancellation in this +integral. And because this is smooth, + + align:start position:0% +integral. And because this is smooth, + + + align:start position:0% +integral. And because this is smooth, +the cancellation is quite dramatic. So + + align:start position:0% +the cancellation is quite dramatic. So + + + align:start position:0% +the cancellation is quite dramatic. So +this is rapidly decaying + + align:start position:0% + + + + align:start position:0% + +x. + + align:start position:0% + + + + align:start position:0% + +Okay, so that's what the size of this + + align:start position:0% +Okay, so that's what the size of this + + + align:start position:0% +Okay, so that's what the size of this +function is like. Um but but also um + + align:start position:0% +function is like. Um but but also um + + + align:start position:0% +function is like. Um but but also um +there's some cancellation in it. So if + + align:start position:0% +there's some cancellation in it. So if + + + align:start position:0% +there's some cancellation in it. So if +you integrate this function + + align:start position:0% +you integrate this function + + + align:start position:0% +you integrate this function +well if you integrate that you get a to + + align:start position:0% +well if you integrate that you get a to + + + align:start position:0% +well if you integrate that you get a to +r of zero which is zero because a to r + + align:start position:0% +r of zero which is zero because a to r + + + align:start position:0% +r of zero which is zero because a to r +is supported on an annulus and not a + + align:start position:0% +is supported on an annulus and not a + + + align:start position:0% +is supported on an annulus and not a +ball. So this function has some + + align:start position:0% +ball. So this function has some + + + align:start position:0% +ball. So this function has some +cancellation in it. It averages to zero. + + align:start position:0% + + + + align:start position:0% + +Okay. + + align:start position:0% + + + + align:start position:0% + +Um so + + align:start position:0% +Um so + + + align:start position:0% +Um so +I I can graph it. Um C sub R check is + + align:start position:0% +I I can graph it. Um C sub R check is + + + align:start position:0% +I I can graph it. Um C sub R check is +radial. + + align:start position:0% +radial. + + + align:start position:0% +radial. +So here is the radius norm of X and + + align:start position:0% +So here is the radius norm of X and + + + align:start position:0% +So here is the radius norm of X and +here's ADA R check of X and it would + + align:start position:0% +here's ADA R check of X and it would + + + align:start position:0% +here's ADA R check of X and it would +look something like this. + + align:start position:0% + + + + align:start position:0% + +And we have to do this carefully but the + + align:start position:0% +And we have to do this carefully but the + + + align:start position:0% +And we have to do this carefully but the +negative part is going to balance the + + align:start position:0% +negative part is going to balance the + + + align:start position:0% +negative part is going to balance the +positive part to integrate to zero. So + + align:start position:0% +positive part to integrate to zero. So + + + align:start position:0% +positive part to integrate to zero. So +imagine rotating this + + align:start position:0% + + + + align:start position:0% + +Um, and this scale here is is that's + + align:start position:0% + + + + align:start position:0% + +okay. Now, these different exponents + + align:start position:0% +okay. Now, these different exponents + + + align:start position:0% +okay. Now, these different exponents +here are + + align:start position:0% +here are + + + align:start position:0% +here are +work out nicely. + + align:start position:0% +work out nicely. + + + align:start position:0% +work out nicely. +Um and and a a different way a way to + + align:start position:0% +Um and and a a different way a way to + + + align:start position:0% +Um and and a a different way a way to +describe it is that if I take the + + align:start position:0% +describe it is that if I take the + + + align:start position:0% +describe it is that if I take the +integral of the norm of a total r check + + align:start position:0% +integral of the norm of a total r check + + + align:start position:0% +integral of the norm of a total r check +of x dx + + align:start position:0% +of x dx + + + align:start position:0% +of x dx +um well it's around 1 / r^2 times the + + align:start position:0% +um well it's around 1 / r^2 times the + + + align:start position:0% +um well it's around 1 / r^2 times the +area of the ball of radius r which is 1. + + align:start position:0% +area of the ball of radius r which is 1. + + + align:start position:0% +area of the ball of radius r which is 1. +That integral is around 1. + + align:start position:0% +That integral is around 1. + + + align:start position:0% +That integral is around 1. +So um so if I were to take some function + + align:start position:0% +So um so if I were to take some function + + + align:start position:0% +So um so if I were to take some function +and convolve it with the absolute value + + align:start position:0% +and convolve it with the absolute value + + + align:start position:0% +and convolve it with the absolute value +of a total r check of x that would + + align:start position:0% +of a total r check of x that would + + + align:start position:0% +of a total r check of x that would +roughly be the average value of f + + align:start position:0% +roughly be the average value of f + + + align:start position:0% +roughly be the average value of f +on the ball around x of radius r the + + align:start position:0% +on the ball around x of radius r the + + + align:start position:0% +on the ball around x of radius r the +sort of weighted average. It's not + + align:start position:0% +sort of weighted average. It's not + + + align:start position:0% +sort of weighted average. It's not +exactly the standard average but that's + + align:start position:0% +exactly the standard average but that's + + + align:start position:0% +exactly the standard average but that's +roughly what what it is. + + align:start position:0% + + + + align:start position:0% + +So is it the case that like + + align:start position:0% +So is it the case that like + + + align:start position:0% +So is it the case that like +um convoluting with a function on the + + align:start position:0% +um convoluting with a function on the + + + align:start position:0% +um convoluting with a function on the +end + + align:start position:0% +end + + + align:start position:0% +end +like if data r is like on the end + + align:start position:0% +like if data r is like on the end + + + align:start position:0% +like if data r is like on the end +basically behaves the same as if it were + + align:start position:0% +basically behaves the same as if it were + + + align:start position:0% +basically behaves the same as if it were +on the fall radius. + + align:start position:0% + + + + align:start position:0% + +>> So the question is how would we compare + + align:start position:0% +>> So the question is how would we compare + + + align:start position:0% +>> So the question is how would we compare +an ad r that's supported on an annulus + + align:start position:0% +an ad r that's supported on an annulus + + + align:start position:0% +an ad r that's supported on an annulus +with a similar function that was + + align:start position:0% +with a similar function that was + + + align:start position:0% +with a similar function that was +supported on the whole ball. Um yeah, + + align:start position:0% +supported on the whole ball. Um yeah, + + + align:start position:0% +supported on the whole ball. Um yeah, +it's mostly similar because of the + + align:start position:0% +it's mostly similar because of the + + + align:start position:0% +it's mostly similar because of the +annulus. There's more cancellation. So + + align:start position:0% +annulus. There's more cancellation. So + + + align:start position:0% +annulus. There's more cancellation. So +if we did it on the whole ball, we + + align:start position:0% +if we did it on the whole ball, we + + + align:start position:0% +if we did it on the whole ball, we +wouldn't have this integral property. + + align:start position:0% +wouldn't have this integral property. + + + align:start position:0% +wouldn't have this integral property. +>> Okay. + + align:start position:0% +>> Okay. + + + align:start position:0% +>> Okay. +>> And the ne there may or may not be a + + align:start position:0% +>> And the ne there may or may not be a + + + align:start position:0% +>> And the ne there may or may not be a +little negative part if we did it on the + + align:start position:0% +little negative part if we did it on the + + + align:start position:0% +little negative part if we did it on the +whole ball, but the negative part would + + align:start position:0% +whole ball, but the negative part would + + + align:start position:0% +whole ball, but the negative part would +probably would be dominated by the + + align:start position:0% +probably would be dominated by the + + + align:start position:0% +probably would be dominated by the +positive part. + + align:start position:0% + + + + align:start position:0% + +Okay, so that's what the function ad + + align:start position:0% +Okay, so that's what the function ad + + + align:start position:0% +Okay, so that's what the function ad +looks like. + + align:start position:0% + + + + align:start position:0% + +And now that we understand that we can + + align:start position:0% +And now that we understand that we can + + + align:start position:0% +And now that we understand that we can +understand the function CTR + + align:start position:0% +understand the function CTR + + + align:start position:0% +understand the function CTR +because CTR is equal to CT convolved + + align:start position:0% +because CTR is equal to CT convolved + + + align:start position:0% +because CTR is equal to CT convolved +with ADA R check. + + align:start position:0% + + + + align:start position:0% + +Okay. So the norm of ctr of x is around + + align:start position:0% +Okay. So the norm of ctr of x is around + + + align:start position:0% +Okay. So the norm of ctr of x is around +r inverse times the characteristic + + align:start position:0% +r inverse times the characteristic + + + align:start position:0% +r inverse times the characteristic +function of a thickened tube. + + align:start position:0% +function of a thickened tube. + + + align:start position:0% +function of a thickened tube. +So if I take the r neighborhood of t. + + align:start position:0% +So if I take the r neighborhood of t. + + + align:start position:0% +So if I take the r neighborhood of t. +So if this is uh t + + align:start position:0% + + + + align:start position:0% + +I could take a fat neighborhood of that + + align:start position:0% +I could take a fat neighborhood of that + + + align:start position:0% +I could take a fat neighborhood of that +would look sort of like this. + + align:start position:0% +would look sort of like this. + + + align:start position:0% +would look sort of like this. +So that's the R neighborhood of T. Um so + + align:start position:0% +So that's the R neighborhood of T. Um so + + + align:start position:0% +So that's the R neighborhood of T. Um so +PT itself is basically supported on T + + align:start position:0% +PT itself is basically supported on T + + + align:start position:0% +PT itself is basically supported on T +although it's smoothed out a little bit. + + align:start position:0% +although it's smoothed out a little bit. + + + align:start position:0% +although it's smoothed out a little bit. +And then when I take the low frequency + + align:start position:0% +And then when I take the low frequency + + + align:start position:0% +And then when I take the low frequency +part the R the one over R frequency part + + align:start position:0% +part the R the one over R frequency part + + + align:start position:0% +part the R the one over R frequency part +then it gets spread out and it gets + + align:start position:0% +then it gets spread out and it gets + + + align:start position:0% +then it gets spread out and it gets +smaller. + + align:start position:0% + + + + align:start position:0% + +Okay. And it also has some cancellation + + align:start position:0% +Okay. And it also has some cancellation + + + align:start position:0% +Okay. And it also has some cancellation +in it. So if the the graph of this + + align:start position:0% +in it. So if the the graph of this + + + align:start position:0% +in it. So if the the graph of this +function mostly depends on the + + align:start position:0% +function mostly depends on the + + + align:start position:0% +function mostly depends on the +transverse direction and then it looks a + + align:start position:0% +transverse direction and then it looks a + + + align:start position:0% +transverse direction and then it looks a +lot like this. So this would be the + + align:start position:0% +lot like this. So this would be the + + + align:start position:0% +lot like this. So this would be the +transverse direction and this would be + + align:start position:0% +transverse direction and this would be + + + align:start position:0% +transverse direction and this would be +the height. + + align:start position:0% + + + + align:start position:0% + +So here I'll put that in the picture. + + align:start position:0% + + + + align:start position:0% + +So this transverse direction maybe I'll + + align:start position:0% +So this transverse direction maybe I'll + + + align:start position:0% +So this transverse direction maybe I'll +call y. + + align:start position:0% +call y. + + + align:start position:0% +call y. +And then we could make a graph where + + align:start position:0% +And then we could make a graph where + + + align:start position:0% +And then we could make a graph where +here we put y and here we put ct + + align:start position:0% +here we put y and here we put ct + + + align:start position:0% +here we put y and here we put ct +r of y and we would see the same thing + + align:start position:0% +r of y and we would see the same thing + + + align:start position:0% +r of y and we would see the same thing +uh positive negative. + + align:start position:0% + + + + align:start position:0% + +Okay. And this length scale here is r. + + align:start position:0% +Okay. And this length scale here is r. + + + align:start position:0% +Okay. And this length scale here is r. +the negative part would cancel the + + align:start position:0% +the negative part would cancel the + + + align:start position:0% +the negative part would cancel the +positive part because if you convolve + + align:start position:0% +positive part because if you convolve + + + align:start position:0% +positive part because if you convolve +something who integrates to zero with + + align:start position:0% +something who integrates to zero with + + + align:start position:0% +something who integrates to zero with +something else then the the whole thing + + align:start position:0% +something else then the the whole thing + + + align:start position:0% +something else then the the whole thing +will integrate to zero. + + align:start position:0% + + + + align:start position:0% + +Okay, so that's what what these + + align:start position:0% +Okay, so that's what what these + + + align:start position:0% +Okay, so that's what what these +functions look like. + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% + + + + align:start position:0% + +All right. + + align:start position:0% + + + + align:start position:0% + +So before I erase this maybe I'll say + + align:start position:0% +So before I erase this maybe I'll say + + + align:start position:0% +So before I erase this maybe I'll say +sorry we mentioned earlier that if we + + align:start position:0% +sorry we mentioned earlier that if we + + + align:start position:0% +sorry we mentioned earlier that if we +have a smooth function supported on this + + align:start position:0% +have a smooth function supported on this + + + align:start position:0% +have a smooth function supported on this +tube we take its 4A transform it's + + align:start position:0% +tube we take its 4A transform it's + + + align:start position:0% +tube we take its 4A transform it's +essentially supported on this dual tube. + + align:start position:0% +essentially supported on this dual tube. + + + align:start position:0% +essentially supported on this dual tube. +That proof is a slightly fancier version + + align:start position:0% +That proof is a slightly fancier version + + + align:start position:0% +That proof is a slightly fancier version +of what we were just talking about. So + + align:start position:0% +of what we were just talking about. So + + + align:start position:0% +of what we were just talking about. So +we were just saying that if you have a + + align:start position:0% +we were just saying that if you have a + + + align:start position:0% +we were just saying that if you have a +smooth function on a certain annulus or + + align:start position:0% +smooth function on a certain annulus or + + + align:start position:0% +smooth function on a certain annulus or +a certain ball then its fora transform + + align:start position:0% +a certain ball then its fora transform + + + align:start position:0% +a certain ball then its fora transform +is essentially supported on a dual ball + + align:start position:0% +is essentially supported on a dual ball + + + align:start position:0% +is essentially supported on a dual ball +and then it's rapidly decaying outside. + + align:start position:0% +and then it's rapidly decaying outside. + + + align:start position:0% +and then it's rapidly decaying outside. +So the this first statement is exactly + + align:start position:0% +So the this first statement is exactly + + + align:start position:0% +So the this first statement is exactly +the same as that except that we have a + + align:start position:0% +the same as that except that we have a + + + align:start position:0% +the same as that except that we have a +tube instead of a ball. Having a tube + + align:start position:0% +tube instead of a ball. Having a tube + + + align:start position:0% +tube instead of a ball. Having a tube +instead of a ball makes it a little + + align:start position:0% +instead of a ball makes it a little + + + align:start position:0% +instead of a ball makes it a little +there's a little bit more writing or + + align:start position:0% +there's a little bit more writing or + + + align:start position:0% +there's a little bit more writing or +thinking involved but it's the same + + align:start position:0% +thinking involved but it's the same + + + align:start position:0% +thinking involved but it's the same +idea. + + align:start position:0% +idea. + + + align:start position:0% +idea. +uh and you'll and and it'll be the + + align:start position:0% +uh and you'll and and it'll be the + + + align:start position:0% +uh and you'll and and it'll be the +details will be on the homework. + + align:start position:0% + + + + align:start position:0% + +Okay. + + align:start position:0% + + + + align:start position:0% + +Okay. So, um in the finite field case, + + align:start position:0% +Okay. So, um in the finite field case, + + + align:start position:0% +Okay. So, um in the finite field case, +the the the the heart of the argument, + + align:start position:0% +the the the the heart of the argument, + + + align:start position:0% +the the the the heart of the argument, +the key thing called the key lema was an + + align:start position:0% +the key thing called the key lema was an + + + align:start position:0% +the key thing called the key lema was an +orthogonality lema that said that the + + align:start position:0% +orthogonality lema that said that the + + + align:start position:0% +orthogonality lema that said that the +high frequency parts of two different + + align:start position:0% +high frequency parts of two different + + + align:start position:0% +high frequency parts of two different +lines are orthogonal. and um something + + align:start position:0% +lines are orthogonal. and um something + + + align:start position:0% +lines are orthogonal. and um something +like that is true here. + + align:start position:0% +like that is true here. + + + align:start position:0% +like that is true here. +So lema on orthogonality this is like + + align:start position:0% +So lema on orthogonality this is like + + + align:start position:0% +So lema on orthogonality this is like +the key letter. So it says the following + + align:start position:0% +the key letter. So it says the following + + + align:start position:0% +the key letter. So it says the following +um uh t1 and t2 are are are tubes one by + + align:start position:0% +um uh t1 and t2 are are are tubes one by + + + align:start position:0% +um uh t1 and t2 are are are tubes one by +r tubes + + align:start position:0% + + + + align:start position:0% + +um then + + align:start position:0% +um then + + + align:start position:0% +um then +the ctrs are usually orthogonal. So if I + + align:start position:0% +the ctrs are usually orthogonal. So if I + + + align:start position:0% +the ctrs are usually orthogonal. So if I +take the inner product of CT1R + + align:start position:0% +take the inner product of CT1R + + + align:start position:0% +take the inner product of CT1R +with CT2R, + + align:start position:0% +with CT2R, + + + align:start position:0% +with CT2R, +it's usually really small. + + align:start position:0% +it's usually really small. + + + align:start position:0% +it's usually really small. +R the minus a,000, something that's + + align:start position:0% +R the minus a,000, something that's + + + align:start position:0% +R the minus a,000, something that's +really small compared to everything in + + align:start position:0% +really small compared to everything in + + + align:start position:0% +really small compared to everything in +our proof. Uh unless the two tubes are + + align:start position:0% +our proof. Uh unless the two tubes are + + + align:start position:0% +our proof. Uh unless the two tubes are +quite similar. And the way we'll say + + align:start position:0% +quite similar. And the way we'll say + + + align:start position:0% +quite similar. And the way we'll say +this is there exists tilda which is like + + align:start position:0% +this is there exists tilda which is like + + + align:start position:0% +this is there exists tilda which is like +basically + + align:start position:0% +basically + + + align:start position:0% +basically +it's basically a little r by big r two. + + align:start position:0% +it's basically a little r by big r two. + + + align:start position:0% +it's basically a little r by big r two. +I'm going to magnify it just a little + + align:start position:0% +I'm going to magnify it just a little + + + align:start position:0% +I'm going to magnify it just a little +bit. + + align:start position:0% +bit. + + + align:start position:0% +bit. +um that contains them both + + align:start position:0% + + + + align:start position:0% + +tilda and inside of here and I have this + + align:start position:0% +tilda and inside of here and I have this + + + align:start position:0% +tilda and inside of here and I have this +t1 and t2. + + align:start position:0% + + + + align:start position:0% + +Okay, so we could have some intuition + + align:start position:0% +Okay, so we could have some intuition + + + align:start position:0% +Okay, so we could have some intuition +about this from our visualization of + + align:start position:0% +about this from our visualization of + + + align:start position:0% +about this from our visualization of +ctr. + + align:start position:0% +ctr. + + + align:start position:0% +ctr. +If I were to take T1 and T2 in in the + + align:start position:0% +If I were to take T1 and T2 in in the + + + align:start position:0% +If I were to take T1 and T2 in in the +same Tilda. So this thickened + + align:start position:0% +same Tilda. So this thickened + + + align:start position:0% +same Tilda. So this thickened +neighborhood notice is basically the + + align:start position:0% +neighborhood notice is basically the + + + align:start position:0% +neighborhood notice is basically the +same as Tilda. If I pick T1 and T2 + + align:start position:0% +same as Tilda. If I pick T1 and T2 + + + align:start position:0% +same as Tilda. If I pick T1 and T2 +corresponding to the same Tilda, then + + align:start position:0% +corresponding to the same Tilda, then + + + align:start position:0% +corresponding to the same Tilda, then +when I when I thicken them both, I get + + align:start position:0% +when I when I thicken them both, I get + + + align:start position:0% +when I when I thicken them both, I get +basically the same rectangle. + + align:start position:0% +basically the same rectangle. + + + align:start position:0% +basically the same rectangle. +And in fact, then the functions CT1R and + + align:start position:0% +And in fact, then the functions CT1R and + + + align:start position:0% +And in fact, then the functions CT1R and +CT2R are basically the same function. So + + align:start position:0% +CT2R are basically the same function. So + + + align:start position:0% +CT2R are basically the same function. So +they are not at all orthogonal. + + align:start position:0% +they are not at all orthogonal. + + + align:start position:0% +they are not at all orthogonal. +And that's the only thing that can go + + align:start position:0% +And that's the only thing that can go + + + align:start position:0% +And that's the only thing that can go +wrong. + + align:start position:0% +wrong. + + + align:start position:0% +wrong. +Um if the thickened neighborhoods are + + align:start position:0% +Um if the thickened neighborhoods are + + + align:start position:0% +Um if the thickened neighborhoods are +disjoint they certainly are orthogonal + + align:start position:0% +disjoint they certainly are orthogonal + + + align:start position:0% +disjoint they certainly are orthogonal +and the more interesting part is that if + + align:start position:0% +and the more interesting part is that if + + + align:start position:0% +and the more interesting part is that if +the thickened neighborhoods are + + align:start position:0% +the thickened neighborhoods are + + + align:start position:0% +the thickened neighborhoods are +transverse to each other they are + + align:start position:0% +transverse to each other they are + + + align:start position:0% +transverse to each other they are +orthogonal + + align:start position:0% + + + + align:start position:0% + +and we we can we check that by by for + + align:start position:0% +and we we can we check that by by for + + + align:start position:0% +and we we can we check that by by for +analysis. + + align:start position:0% +analysis. + + + align:start position:0% +analysis. +Um + + align:start position:0% +Um + + + align:start position:0% +Um +so proof sketch. + + align:start position:0% + + + + align:start position:0% + +Um + + align:start position:0% +Um + + + align:start position:0% +Um +if the + + align:start position:0% +if the + + + align:start position:0% +if the +if the angle + + align:start position:0% + + + + align:start position:0% + +between t1 and t2 is bigger than maybe r + + align:start position:0% +between t1 and t2 is bigger than maybe r + + + align:start position:0% +between t1 and t2 is bigger than maybe r +epsilon 1 / r or little r big r. + + align:start position:0% +epsilon 1 / r or little r big r. + + + align:start position:0% +epsilon 1 / r or little r big r. +Um then + + align:start position:0% +Um then + + + align:start position:0% +Um then +the support + + align:start position:0% +the support + + + align:start position:0% +the support +of CTR hat intercepted the support T1 of + + align:start position:0% +of CTR hat intercepted the support T1 of + + + align:start position:0% +of CTR hat intercepted the support T1 of +CT2R + + align:start position:0% +CT2R + + + align:start position:0% +CT2R +hat is empty + + align:start position:0% +hat is empty + + + align:start position:0% +hat is empty +right so the support of CT1 + + align:start position:0% +right so the support of CT1 + + + align:start position:0% +right so the support of CT1 +so this is the support of CT1 hat + + align:start position:0% +so this is the support of CT1 hat + + + align:start position:0% +so this is the support of CT1 hat +intersected with the annulus of size 1 / + + align:start position:0% +intersected with the annulus of size 1 / + + + align:start position:0% +intersected with the annulus of size 1 / +are + + align:start position:0% +are + + + align:start position:0% +are +intersected with the support of CT2 hat + + align:start position:0% +intersected with the support of CT2 hat + + + align:start position:0% +intersected with the support of CT2 hat +and these are two rectangles that are + + align:start position:0% +and these are two rectangles that are + + + align:start position:0% +and these are two rectangles that are +transverse to each other. Uh and so wow + + align:start position:0% +transverse to each other. Uh and so wow + + + align:start position:0% +transverse to each other. Uh and so wow +and you can you can check the + + align:start position:0% +and you can you can check the + + + align:start position:0% +and you can you can check the +intersection. + + align:start position:0% +intersection. + + + align:start position:0% +intersection. +>> Why does it rule out the translations of + + align:start position:0% +>> Why does it rule out the translations of + + + align:start position:0% +>> Why does it rule out the translations of +rectangles? + + align:start position:0% +rectangles? + + + align:start position:0% +rectangles? +>> Yeah. And so that's case one. So the + + align:start position:0% +>> Yeah. And so that's case one. So the + + + align:start position:0% +>> Yeah. And so that's case one. So the +other case is if um the R neighborhood + + align:start position:0% +other case is if um the R neighborhood + + + align:start position:0% +other case is if um the R neighborhood +of T1 is disjoint + + align:start position:0% +of T1 is disjoint + + + align:start position:0% +of T1 is disjoint +from the R neighborhood of T2 or you + + align:start position:0% +from the R neighborhood of T2 or you + + + align:start position:0% +from the R neighborhood of T2 or you +know a little bit more than R. Um then + + align:start position:0% +know a little bit more than R. Um then + + + align:start position:0% +know a little bit more than R. Um then +we use the formula + + align:start position:0% +we use the formula + + + align:start position:0% +we use the formula +CTR is CT1. + + align:start position:0% +CTR is CT1. + + + align:start position:0% +CTR is CT1. +So that so then we have here + + align:start position:0% +So that so then we have here + + + align:start position:0% +So that so then we have here +integral ct1 r c2 r complex conjugate + + align:start position:0% +integral ct1 r c2 r complex conjugate + + + align:start position:0% +integral ct1 r c2 r complex conjugate +it's the integral ct1 convolved with ad1 + + align:start position:0% +it's the integral ct1 convolved with ad1 + + + align:start position:0% +it's the integral ct1 convolved with ad1 +and ct2 convolved + + align:start position:0% +and ct2 convolved + + + align:start position:0% +and ct2 convolved +a r check and and these two guys have + + align:start position:0% +a r check and and these two guys have + + + align:start position:0% +a r check and and these two guys have +disjoint report. + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +Okay. + + align:start position:0% +Okay. + + + align:start position:0% +Okay. +So now we are ready to estimate the L2 + + align:start position:0% +So now we are ready to estimate the L2 + + + align:start position:0% +So now we are ready to estimate the L2 +norm. Um so our orthogonality lema says + + align:start position:0% +norm. Um so our orthogonality lema says + + + align:start position:0% +norm. Um so our orthogonality lema says +that these different CTRs + + align:start position:0% +that these different CTRs + + + align:start position:0% +that these different CTRs +are usually orthogonal with a few + + align:start position:0% +are usually orthogonal with a few + + + align:start position:0% +are usually orthogonal with a few +exceptions and we're going to use that + + align:start position:0% +exceptions and we're going to use that + + + align:start position:0% +exceptions and we're going to use that +orthogonality to estimate the L2 norm. + + align:start position:0% +orthogonality to estimate the L2 norm. + + + align:start position:0% +orthogonality to estimate the L2 norm. +But we have to keep track of how many + + align:start position:0% +But we have to keep track of how many + + + align:start position:0% +But we have to keep track of how many +exceptions there are. + + align:start position:0% + + + + align:start position:0% + +All right. So, L2 estimate. + + align:start position:0% + + + + align:start position:0% + +So, the last thing we need to check is + + align:start position:0% +So, the last thing we need to check is + + + align:start position:0% +So, the last thing we need to check is +FR L2 squared. So, FR is the sum over + + align:start position:0% +FR L2 squared. So, FR is the sum over + + + align:start position:0% +FR L2 squared. So, FR is the sum over +all of our T of ctr. + + align:start position:0% +all of our T of ctr. + + + align:start position:0% +all of our T of ctr. +L2 squ. + + align:start position:0% +L2 squ. + + + align:start position:0% +L2 squ. +So that's this thing inner product with + + align:start position:0% +So that's this thing inner product with + + + align:start position:0% +So that's this thing inner product with +itself. So if I expand it out, it's the + + align:start position:0% +itself. So if I expand it out, it's the + + + align:start position:0% +itself. So if I expand it out, it's the +sum T1 T2 of um + + align:start position:0% +sum T1 T2 of um + + + align:start position:0% +sum T1 T2 of um +the inner product of C T1R + + align:start position:0% +the inner product of C T1R + + + align:start position:0% +the inner product of C T1R +C T2R. + + align:start position:0% + + + + align:start position:0% + +Okay. And the key point is orthogonality + + align:start position:0% +Okay. And the key point is orthogonality + + + align:start position:0% +Okay. And the key point is orthogonality +lema tells us that most of the inner + + align:start position:0% +lema tells us that most of the inner + + + align:start position:0% +lema tells us that most of the inner +products in this sum are negligible. + + align:start position:0% +products in this sum are negligible. + + + align:start position:0% +products in this sum are negligible. +There's only a few that are not. Let me + + align:start position:0% +There's only a few that are not. Let me + + + align:start position:0% +There's only a few that are not. Let me +give a bit of a name to the ones that + + align:start position:0% +give a bit of a name to the ones that + + + align:start position:0% +give a bit of a name to the ones that +are not. + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% + + + + align:start position:0% + +So this scenario + + align:start position:0% +So this scenario + + + align:start position:0% +So this scenario +here + + align:start position:0% +here + + + align:start position:0% +here +I'm going to abbreviate it as saying + + align:start position:0% +I'm going to abbreviate it as saying + + + align:start position:0% +I'm going to abbreviate it as saying +that T1 uh is related to T2. T T T T T T + + align:start position:0% +that T1 uh is related to T2. T T T T T T + + + align:start position:0% +that T1 uh is related to T2. T T T T T T +T T T T T T T T T T T T T T T T T T T T + + align:start position:0% +T T T T T T T T T T T T T T T T T T T T + + + align:start position:0% +T T T T T T T T T T T T T T T T T T T T +T T T T T T T T T T T T T T T1 is close + + align:start position:0% +T T T T T T T T T T T T T T T1 is close + + + align:start position:0% +T T T T T T T T T T T T T T T1 is close +to T2. + + align:start position:0% +to T2. + + + align:start position:0% +to T2. +I guess we could put a little r here. + + align:start position:0% +I guess we could put a little r here. + + + align:start position:0% +I guess we could put a little r here. +So this inner product is negligible + + align:start position:0% +So this inner product is negligible + + + align:start position:0% +So this inner product is negligible +unless T1 is related to T2. + + align:start position:0% +unless T1 is related to T2. + + + align:start position:0% +unless T1 is related to T2. +Okay, + + align:start position:0% +Okay, + + + align:start position:0% +Okay, +so let's look at our big sum of inner + + align:start position:0% +so let's look at our big sum of inner + + + align:start position:0% +so let's look at our big sum of inner +products + + align:start position:0% + + + + align:start position:0% + +and I'll break it up into two parts. + + align:start position:0% +and I'll break it up into two parts. + + + align:start position:0% +and I'll break it up into two parts. +It's the sum where T1 is related to T2 + + align:start position:0% +It's the sum where T1 is related to T2 + + + align:start position:0% +It's the sum where T1 is related to T2 +inner product plus the rest of them and + + align:start position:0% +inner product plus the rest of them and + + + align:start position:0% +inner product plus the rest of them and +the rest of them are really tiny by the + + align:start position:0% +the rest of them are really tiny by the + + + align:start position:0% +the rest of them are really tiny by the +orthogonality lema. So the rest of them + + align:start position:0% +orthogonality lema. So the rest of them + + + align:start position:0% +orthogonality lema. So the rest of them +are negligible. + + align:start position:0% + + + + align:start position:0% + +Okay. Now each of these inner products + + align:start position:0% +Okay. Now each of these inner products + + + align:start position:0% +Okay. Now each of these inner products +I'll arithmetic geometric mean it. So + + align:start position:0% +I'll arithmetic geometric mean it. So + + + align:start position:0% +I'll arithmetic geometric mean it. So +that's less than this sum t1 related to + + align:start position:0% +that's less than this sum t1 related to + + + align:start position:0% +that's less than this sum t1 related to +t2 + + align:start position:0% +t2 + + + align:start position:0% +t2 +of ctr + + align:start position:0% +of ctr + + + align:start position:0% +of ctr +l2 + + align:start position:0% +l2 + + + align:start position:0% +l2 +ct1 r l2 2 plus ct2r l2. + + align:start position:0% + + + + align:start position:0% + +Okay. So I want to know how many times + + align:start position:0% +Okay. So I want to know how many times + + + align:start position:0% +Okay. So I want to know how many times +does each of these functions ct1 appear + + align:start position:0% +does each of these functions ct1 appear + + + align:start position:0% +does each of these functions ct1 appear +in this sum + + align:start position:0% +in this sum + + + align:start position:0% +in this sum +and the number of times is the number of + + align:start position:0% +and the number of times is the number of + + + align:start position:0% +and the number of times is the number of +different t2s that are related to t1 + + align:start position:0% +different t2s that are related to t1 + + + align:start position:0% +different t2s that are related to t1 +and that number is basically the number + + align:start position:0% +and that number is basically the number + + + align:start position:0% +and that number is basically the number +that appears in our main lema. + + align:start position:0% +that appears in our main lema. + + + align:start position:0% +that appears in our main lema. +This thing that we were counting here + + align:start position:0% +This thing that we were counting here + + + align:start position:0% +This thing that we were counting here +how many tubes lie in a little r by big + + align:start position:0% +how many tubes lie in a little r by big + + + align:start position:0% +how many tubes lie in a little r by big +r big tube. That's exactly how many + + align:start position:0% +r big tube. That's exactly how many + + + align:start position:0% +r big tube. That's exactly how many +tubes t2 are related to t1. + + align:start position:0% +tubes t2 are related to t1. + + + align:start position:0% +tubes t2 are related to t1. +So this thing + + align:start position:0% +So this thing + + + align:start position:0% +So this thing +uh + + align:start position:0% +uh + + + align:start position:0% +uh +we can say the number of t2 so that t2 + + align:start position:0% +we can say the number of t2 so that t2 + + + align:start position:0% +we can say the number of t2 so that t2 +is related to t1 + + align:start position:0% +is related to t1 + + + align:start position:0% +is related to t1 +this is bounded by nr of t. So this + + align:start position:0% +this is bounded by nr of t. So this + + + align:start position:0% +this is bounded by nr of t. So this +whole sum is bounded by + + align:start position:0% +whole sum is bounded by + + + align:start position:0% +whole sum is bounded by +nr of t times just the sum on all the t + + align:start position:0% +nr of t times just the sum on all the t + + + align:start position:0% +nr of t times just the sum on all the t +and t of ctr l2. + + align:start position:0% + + + + align:start position:0% + +Cool. And then finally each of these + + align:start position:0% +Cool. And then finally each of these + + + align:start position:0% +Cool. And then finally each of these +functions we've already described. + + align:start position:0% +functions we've already described. + + + align:start position:0% +functions we've already described. +Hopefully I didn't erase it. + + align:start position:0% +Hopefully I didn't erase it. + + + align:start position:0% +Hopefully I didn't erase it. +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +Yeah, so we described it. It has height + + align:start position:0% +Yeah, so we described it. It has height + + + align:start position:0% +Yeah, so we described it. It has height +r inverse and it's supported on a little + + align:start position:0% +r inverse and it's supported on a little + + + align:start position:0% +r inverse and it's supported on a little +r by big r rectangle. So we can compute + + align:start position:0% +r by big r rectangle. So we can compute + + + align:start position:0% +r by big r rectangle. So we can compute +its L2 norm. Um + + align:start position:0% +its L2 norm. Um + + + align:start position:0% +its L2 norm. Um +so this is n subt of r times the number + + align:start position:0% +so this is n subt of r times the number + + + align:start position:0% +so this is n subt of r times the number +of tubes times uh the height was r + + align:start position:0% +of tubes times uh the height was r + + + align:start position:0% +of tubes times uh the height was r +inverse. So that's rus 2 times the + + align:start position:0% +inverse. So that's rus 2 times the + + + align:start position:0% +inverse. So that's rus 2 times the +uh so this is the amplitude squared + + align:start position:0% +uh so this is the amplitude squared + + + align:start position:0% +uh so this is the amplitude squared +and this is the area + + align:start position:0% + + + + align:start position:0% + +for this ptr. + + align:start position:0% +for this ptr. + + + align:start position:0% +for this ptr. +Okay. And that was the thing that was on + + align:start position:0% +Okay. And that was the thing that was on + + + align:start position:0% +Okay. And that was the thing that was on +the right hand side. + + align:start position:0% + + + + align:start position:0% + +Okay. Let me summarize the proof for the + + align:start position:0% +Okay. Let me summarize the proof for the + + + align:start position:0% +Okay. Let me summarize the proof for the +last minute. Um let's look back at our + + align:start position:0% +last minute. Um let's look back at our + + + align:start position:0% +last minute. Um let's look back at our +statement here. + + align:start position:0% + + + + align:start position:0% + +So if we look at this sum of sum of + + align:start position:0% +So if we look at this sum of sum of + + + align:start position:0% +So if we look at this sum of sum of +tubes, we're going to break it into + + align:start position:0% +tubes, we're going to break it into + + + align:start position:0% +tubes, we're going to break it into +different frequency pieces. Littlewood + + align:start position:0% +different frequency pieces. Littlewood + + + align:start position:0% +different frequency pieces. Littlewood +pale theory. And then um the + + align:start position:0% +pale theory. And then um the + + + align:start position:0% +pale theory. And then um the +highfrequency pieces are usually + + align:start position:0% +highfrequency pieces are usually + + + align:start position:0% +highfrequency pieces are usually +orthogonal to each other. If you take if + + align:start position:0% +orthogonal to each other. If you take if + + + align:start position:0% +orthogonal to each other. If you take if +you look at two tubes and you look at + + align:start position:0% +you look at two tubes and you look at + + + align:start position:0% +you look at two tubes and you look at +the frequency one over R part, they're + + align:start position:0% +the frequency one over R part, they're + + + align:start position:0% +the frequency one over R part, they're +orthogonal to each other unless those + + align:start position:0% +orthogonal to each other unless those + + + align:start position:0% +orthogonal to each other unless those +two tubes are in a common fat tube + + align:start position:0% +two tubes are in a common fat tube + + + align:start position:0% +two tubes are in a common fat tube +little R by big R. + + align:start position:0% +little R by big R. + + + align:start position:0% +little R by big R. +And so you take advantage of that + + align:start position:0% +And so you take advantage of that + + + align:start position:0% +And so you take advantage of that +orthogonality where it's available and + + align:start position:0% +orthogonality where it's available and + + + align:start position:0% +orthogonality where it's available and +it gives this bound. + + align:start position:0% + + + + align:start position:0% + +Okay, good. Let's stop there for today. + + align:start position:0% +Okay, good. Let's stop there for today. + + + align:start position:0% +Okay, good. Let's stop there for today. +uh we will wrap this up on Thursday and + + align:start position:0% +uh we will wrap this up on Thursday and + + + align:start position:0% +uh we will wrap this up on Thursday and +and then uh discuss how similar ideas + + align:start position:0% +and then uh discuss how similar ideas + + + align:start position:0% +and then uh discuss how similar ideas +apply in a different looking context in + + align:start position:0% +apply in a different looking context in + + + align:start position:0% +apply in a different looking context in +civ theory in in number theory. \ No newline at end of file diff --git a/ONYokXoy04Q.txt b/ONYokXoy04Q.txt new file mode 100644 index 0000000000000000000000000000000000000000..bc7d9f1e00b763bb2c4e2004aadee8a1102b2e6a --- /dev/null +++ b/ONYokXoy04Q.txt @@ -0,0 +1,6435 @@ +align:start position:0% + +so what I want to do today is recap a + + align:start position:0% +so what I want to do today is recap a + + + align:start position:0% +so what I want to do today is recap a +little bit what we talked about last + + align:start position:0% +little bit what we talked about last + + + align:start position:0% +little bit what we talked about last +time um reiterate some of the important + + align:start position:0% +time um reiterate some of the important + + + align:start position:0% +time um reiterate some of the important +points and then um show you uh how we + + align:start position:0% +points and then um show you uh how we + + + align:start position:0% +points and then um show you uh how we +can learn something about microorganisms + + align:start position:0% +can learn something about microorganisms + + + align:start position:0% +can learn something about microorganisms +in the environment by talking about + + align:start position:0% +in the environment by talking about + + + align:start position:0% +in the environment by talking about +inito identification of microorganisms + + align:start position:0% +inito identification of microorganisms + + + align:start position:0% +inito identification of microorganisms +as well as um genomics um we'll first + + align:start position:0% +as well as um genomics um we'll first + + + align:start position:0% +as well as um genomics um we'll first +talk about genomics in general and then + + align:start position:0% +talk about genomics in general and then + + + align:start position:0% +talk about genomics in general and then +talk about some applications of genomics + + align:start position:0% +talk about some applications of genomics + + + align:start position:0% +talk about some applications of genomics +to environmental microbiology because I + + align:start position:0% +to environmental microbiology because I + + + align:start position:0% +to environmental microbiology because I +think there's some of the most exciting + + align:start position:0% +think there's some of the most exciting + + + align:start position:0% +think there's some of the most exciting +new developments are in that area + + align:start position:0% +new developments are in that area + + + align:start position:0% +new developments are in that area +actually so last time um we talked about + + align:start position:0% + + + + align:start position:0% + +molecular + + align:start position:0% + + + + align:start position:0% + +Evolution and + + align:start position:0% + + + + align:start position:0% + +ecology and just to recap some of the + + align:start position:0% +ecology and just to recap some of the + + + align:start position:0% +ecology and just to recap some of the +main points where that we can use genes + + align:start position:0% +main points where that we can use genes + + + align:start position:0% +main points where that we can use genes +or Gene + + align:start position:0% + + + + align:start position:0% + +sequences for a couple of very + + align:start position:0% +sequences for a couple of very + + + align:start position:0% +sequences for a couple of very +important + + align:start position:0% +important + + + align:start position:0% +important +um uh uh uh questions that we uh want to + + align:start position:0% +um uh uh uh questions that we uh want to + + + align:start position:0% +um uh uh uh questions that we uh want to +explore the first one was Gene sequences + + align:start position:0% +explore the first one was Gene sequences + + + align:start position:0% +explore the first one was Gene sequences +act as evolutionary chronometers + + align:start position:0% + + + + align:start position:0% + +now what do we mean by that basically + + align:start position:0% +now what do we mean by that basically + + + align:start position:0% +now what do we mean by that basically +what we said last time is that each gene + + align:start position:0% +what we said last time is that each gene + + + align:start position:0% +what we said last time is that each gene +each sequence in a genome accumulates + + align:start position:0% +each sequence in a genome accumulates + + + align:start position:0% +each sequence in a genome accumulates +mutation with a certain + + align:start position:0% + + + + align:start position:0% + +probability so what we mean is that all + + align:start position:0% + + + + align:start position:0% + +genes + + align:start position:0% + + + + align:start position:0% + +accumulate + + align:start position:0% +accumulate + + + align:start position:0% +accumulate +mutations over time + + align:start position:0% + + + + align:start position:0% + +now these of course are the mutations + + align:start position:0% +now these of course are the mutations + + + align:start position:0% +now these of course are the mutations +that do not kill the organism so not the + + align:start position:0% +that do not kill the organism so not the + + + align:start position:0% +that do not kill the organism so not the +delerious mutations but these are + + align:start position:0% +delerious mutations but these are + + + align:start position:0% +delerious mutations but these are +mutations that are either slightly + + align:start position:0% +mutations that are either slightly + + + align:start position:0% +mutations that are either slightly +delerious or don't matter or the + + align:start position:0% +delerious or don't matter or the + + + align:start position:0% +delerious or don't matter or the +beneficial mutations + + align:start position:0% +beneficial mutations + + + align:start position:0% +beneficial mutations +okay and what this entails that each + + align:start position:0% +okay and what this entails that each + + + align:start position:0% +okay and what this entails that each +gene accumulates mutation with a certain + + align:start position:0% +gene accumulates mutation with a certain + + + align:start position:0% +gene accumulates mutation with a certain +probability over time it basically means + + align:start position:0% +probability over time it basically means + + + align:start position:0% +probability over time it basically means +um that two organisms that come from + + align:start position:0% +um that two organisms that come from + + + align:start position:0% +um that two organisms that come from +species that are relatively closely + + align:start position:0% +species that are relatively closely + + + align:start position:0% +species that are relatively closely +related to each other have uh their Gene + + align:start position:0% +related to each other have uh their Gene + + + align:start position:0% +related to each other have uh their Gene +sequences will be much more similar to + + align:start position:0% +sequences will be much more similar to + + + align:start position:0% +sequences will be much more similar to +each other than um genes from an + + align:start position:0% +each other than um genes from an + + + align:start position:0% +each other than um genes from an +organism that comes from a species + + align:start position:0% +organism that comes from a species + + + align:start position:0% +organism that comes from a species +that's much more distantly related so in + + align:start position:0% +that's much more distantly related so in + + + align:start position:0% +that's much more distantly related so in +in Practical terms what this means is + + align:start position:0% +in Practical terms what this means is + + + align:start position:0% +in Practical terms what this means is +your genes are much much more similar to + + align:start position:0% +your genes are much much more similar to + + + align:start position:0% +your genes are much much more similar to +those of a monkey than they are to a + + align:start position:0% +those of a monkey than they are to a + + + align:start position:0% +those of a monkey than they are to a +crocodile for example and we can take + + align:start position:0% +crocodile for example and we can take + + + align:start position:0% +crocodile for example and we can take +advantage of that by applying some + + align:start position:0% +advantage of that by applying some + + + align:start position:0% +advantage of that by applying some +algorithms some mathemat mathematical + + align:start position:0% +algorithms some mathemat mathematical + + + align:start position:0% +algorithms some mathemat mathematical +modeling essentially to constrain these + + align:start position:0% +modeling essentially to constrain these + + + align:start position:0% +modeling essentially to constrain these +relationships in those philogenetic + + align:start position:0% +relationships in those philogenetic + + + align:start position:0% +relationships in those philogenetic +trees that we uh talked about last time + + align:start position:0% +trees that we uh talked about last time + + + align:start position:0% +trees that we uh talked about last time +and I also mentioned that the ribosomal + + align:start position:0% +and I also mentioned that the ribosomal + + + align:start position:0% +and I also mentioned that the ribosomal +RNA + + align:start position:0% + + + + align:start position:0% + +genes are particularly important for + + align:start position:0% +genes are particularly important for + + + align:start position:0% +genes are particularly important for +that process in principle you could do + + align:start position:0% +that process in principle you could do + + + align:start position:0% +that process in principle you could do +it with any protein coding gene or any + + align:start position:0% +it with any protein coding gene or any + + + align:start position:0% +it with any protein coding gene or any +kind of gene in a genome but we use the + + align:start position:0% +kind of gene in a genome but we use the + + + align:start position:0% +kind of gene in a genome but we use the +ribosomal RNA genes in particular + + align:start position:0% +ribosomal RNA genes in particular + + + align:start position:0% +ribosomal RNA genes in particular +because all organisms have them they're + + align:start position:0% +because all organisms have them they're + + + align:start position:0% +because all organisms have them they're +part of a handful of genes that are what + + align:start position:0% +part of a handful of genes that are what + + + align:start position:0% +part of a handful of genes that are what +we called universally distributed last + + align:start position:0% +we called universally distributed last + + + align:start position:0% +we called universally distributed last +time and what this allows us to do is + + align:start position:0% +time and what this allows us to do is + + + align:start position:0% +time and what this allows us to do is +then to construct philogenetic + + align:start position:0% +then to construct philogenetic + + + align:start position:0% +then to construct philogenetic +relationships for all living organisms + + align:start position:0% +relationships for all living organisms + + + align:start position:0% +relationships for all living organisms +okay and I just want to remind you of + + align:start position:0% +okay and I just want to remind you of + + + align:start position:0% +okay and I just want to remind you of +the tree of life that I showed last time + + align:start position:0% +the tree of life that I showed last time + + + align:start position:0% +the tree of life that I showed last time +where we can really explore um the + + align:start position:0% +where we can really explore um the + + + align:start position:0% +where we can really explore um the +relationships amongst all living + + align:start position:0% +relationships amongst all living + + + align:start position:0% +relationships amongst all living +organisms and um some of the important + + align:start position:0% +organisms and um some of the important + + + align:start position:0% +organisms and um some of the important +points there that we made where for + + align:start position:0% +points there that we made where for + + + align:start position:0% +points there that we made where for +example that the Tree of Life supports + + align:start position:0% +example that the Tree of Life supports + + + align:start position:0% +example that the Tree of Life supports +the endos Symon theory that when you + + align:start position:0% +the endos Symon theory that when you + + + align:start position:0% +the endos Symon theory that when you +actually look on the tree where the + + align:start position:0% +actually look on the tree where the + + + align:start position:0% +actually look on the tree where the +mitochondria and the chloroplasts tree + + align:start position:0% +mitochondria and the chloroplasts tree + + + align:start position:0% +mitochondria and the chloroplasts tree +they fall into the + + align:start position:0% +they fall into the + + + align:start position:0% +they fall into the +bacteria now there was a question um + + align:start position:0% +bacteria now there was a question um + + + align:start position:0% +bacteria now there was a question um +where somebody asked uh in in your + + align:start position:0% +where somebody asked uh in in your + + + align:start position:0% +where somebody asked uh in in your +online + + align:start position:0% +online + + + align:start position:0% +online +survey um Can the mitochondria and + + align:start position:0% +survey um Can the mitochondria and + + + align:start position:0% +survey um Can the mitochondria and +chloroplast still live outside of the + + align:start position:0% +chloroplast still live outside of the + + + align:start position:0% +chloroplast still live outside of the +eukaryotic cell and the answer is no + + align:start position:0% +eukaryotic cell and the answer is no + + + align:start position:0% +eukaryotic cell and the answer is no +they can't anymore because um the over + + align:start position:0% +they can't anymore because um the over + + + align:start position:0% +they can't anymore because um the over +evolutionary times the two organisms + + align:start position:0% +evolutionary times the two organisms + + + align:start position:0% +evolutionary times the two organisms +have have become so integrated that um + + align:start position:0% +have have become so integrated that um + + + align:start position:0% +have have become so integrated that um +the mitochondria and chloroplasts have + + align:start position:0% +the mitochondria and chloroplasts have + + + align:start position:0% +the mitochondria and chloroplasts have +both lost their ability to live outside + + align:start position:0% +both lost their ability to live outside + + + align:start position:0% +both lost their ability to live outside +of the eukariotic + + align:start position:0% + + + + align:start position:0% + +hostel another important point that we + + align:start position:0% +hostel another important point that we + + + align:start position:0% +hostel another important point that we +made last + + align:start position:0% +made last + + + align:start position:0% +made last +time um that I want to reiterate here is + + align:start position:0% +time um that I want to reiterate here is + + + align:start position:0% +time um that I want to reiterate here is +that Gene sequences when we go into the + + align:start position:0% +that Gene sequences when we go into the + + + align:start position:0% +that Gene sequences when we go into the +environment and obtain them directly + + align:start position:0% +environment and obtain them directly + + + align:start position:0% +environment and obtain them directly +from the environment act as a proxy for + + align:start position:0% +from the environment act as a proxy for + + + align:start position:0% +from the environment act as a proxy for +microbial diversity in the + + align:start position:0% +microbial diversity in the + + + align:start position:0% +microbial diversity in the +environment so the number + + align:start position:0% +environment so the number + + + align:start position:0% +environment so the number +of + + align:start position:0% +of + + + align:start position:0% +of +genes recover + + align:start position:0% + + + + align:start position:0% + +directly from the + + align:start position:0% + + + + align:start position:0% + +environment is a + + align:start position:0% + + + + align:start position:0% + +measure of diversity + + align:start position:0% + + + + align:start position:0% + +and we said that this actually plays a + + align:start position:0% +and we said that this actually plays a + + + align:start position:0% +and we said that this actually plays a +very very important role in the analysis + + align:start position:0% +very very important role in the analysis + + + align:start position:0% +very very important role in the analysis +of microbial communities and I showed + + align:start position:0% +of microbial communities and I showed + + + align:start position:0% +of microbial communities and I showed +you this example here where we went to + + align:start position:0% +you this example here where we went to + + + align:start position:0% +you this example here where we went to +um took some ocean water and basically + + align:start position:0% +um took some ocean water and basically + + + align:start position:0% +um took some ocean water and basically +applied this technique that I outlined + + align:start position:0% +applied this technique that I outlined + + + align:start position:0% +applied this technique that I outlined +last time where we can actually amplify + + align:start position:0% +last time where we can actually amplify + + + align:start position:0% +last time where we can actually amplify +ribosomal RNA genes from environmental + + align:start position:0% +ribosomal RNA genes from environmental + + + align:start position:0% +ribosomal RNA genes from environmental +samples clone them determine the + + align:start position:0% +samples clone them determine the + + + align:start position:0% +samples clone them determine the +sequence and then construct philogenetic + + align:start position:0% +sequence and then construct philogenetic + + + align:start position:0% +sequence and then construct philogenetic +trees and what you see here is a tree + + align:start position:0% +trees and what you see here is a tree + + + align:start position:0% +trees and what you see here is a tree +where + + align:start position:0% +where + + + align:start position:0% +where +we uh uh summarize the major groups that + + align:start position:0% +we uh uh summarize the major groups that + + + align:start position:0% +we uh uh summarize the major groups that +we found in this uh sample and then only + + align:start position:0% +we found in this uh sample and then only + + + align:start position:0% +we found in this uh sample and then only +for two of those groups do we show the + + align:start position:0% +for two of those groups do we show the + + + align:start position:0% +for two of those groups do we show the +entire set of sequences that we actually + + align:start position:0% +entire set of sequences that we actually + + + align:start position:0% +entire set of sequences that we actually +obtained because there were so many of + + align:start position:0% +obtained because there were so many of + + + align:start position:0% +obtained because there were so many of +them out there and what we basically + + align:start position:0% +them out there and what we basically + + + align:start position:0% +them out there and what we basically +found is that over 1,500 bacterial 6s + + align:start position:0% +found is that over 1,500 bacterial 6s + + + align:start position:0% +found is that over 1,500 bacterial 6s +ribosomal RNA Gene sequences coexist in + + align:start position:0% +ribosomal RNA Gene sequences coexist in + + + align:start position:0% +ribosomal RNA Gene sequences coexist in +this in in this environment and what we + + align:start position:0% +this in in this environment and what we + + + align:start position:0% +this in in this environment and what we +said also last time is that analysis + + align:start position:0% +said also last time is that analysis + + + align:start position:0% +said also last time is that analysis +like these have really taught us that + + align:start position:0% +like these have really taught us that + + + align:start position:0% +like these have really taught us that +microorganisms are the most diverse + + align:start position:0% +microorganisms are the most diverse + + + align:start position:0% +microorganisms are the most diverse +organism in the planet so most diversity + + align:start position:0% +organism in the planet so most diversity + + + align:start position:0% +organism in the planet so most diversity +is amongst the microorganisms and one of + + align:start position:0% +is amongst the microorganisms and one of + + + align:start position:0% +is amongst the microorganisms and one of +the big questions now is um what are all + + align:start position:0% +the big questions now is um what are all + + + align:start position:0% +the big questions now is um what are all +those microorganisms doing in the + + align:start position:0% +those microorganisms doing in the + + + align:start position:0% +those microorganisms doing in the +environment and so today what I want to + + align:start position:0% +environment and so today what I want to + + + align:start position:0% +environment and so today what I want to +do with you is basically explore this + + align:start position:0% +do with you is basically explore this + + + align:start position:0% +do with you is basically explore this +question how we can actually figure out + + align:start position:0% +question how we can actually figure out + + + align:start position:0% +question how we can actually figure out +what those microorganisms are all doing + + align:start position:0% +what those microorganisms are all doing + + + align:start position:0% +what those microorganisms are all doing +in environmental samples + + align:start position:0% + + + + align:start position:0% + +so we can say we're exploring the + + align:start position:0% + + + + align:start position:0% + +function of microbes in the + + align:start position:0% + + + + align:start position:0% + +environment and first I want to cover + + align:start position:0% +environment and first I want to cover + + + align:start position:0% +environment and first I want to cover +how we can + + align:start position:0% +how we can + + + align:start position:0% +how we can +actually identify them in C2 in the + + align:start position:0% +actually identify them in C2 in the + + + align:start position:0% +actually identify them in C2 in the +environment + + align:start position:0% + + + + align:start position:0% + +and I want to show you one specific + + align:start position:0% +and I want to show you one specific + + + align:start position:0% +and I want to show you one specific +example and then I want to talk about + + align:start position:0% +example and then I want to talk about + + + align:start position:0% +example and then I want to talk about +genomics in + + align:start position:0% + + + + align:start position:0% + +general and then basically end with an + + align:start position:0% +general and then basically end with an + + + align:start position:0% +general and then basically end with an +application of genomics to environmental + + align:start position:0% + + + + align:start position:0% + +questions so let's + + align:start position:0% +questions so let's + + + align:start position:0% +questions so let's +first talk about the Ino identification + + align:start position:0% +first talk about the Ino identification + + + align:start position:0% +first talk about the Ino identification +of microorganisms + + align:start position:0% + + + + align:start position:0% + +and the basic problem that I alluded to + + align:start position:0% +and the basic problem that I alluded to + + + align:start position:0% +and the basic problem that I alluded to +already before is that most microbes are + + align:start position:0% +already before is that most microbes are + + + align:start position:0% +already before is that most microbes are +only known + + align:start position:0% + + + + align:start position:0% + +from 16s ribosomal RNA clone + + align:start position:0% + + + + align:start position:0% + +libraries and we basically want to + + align:start position:0% +libraries and we basically want to + + + align:start position:0% +libraries and we basically want to +search and identify + + align:start position:0% + + + + align:start position:0% + +them in the environment + + align:start position:0% + + + + align:start position:0% + +okay and I'll show you a specific + + align:start position:0% +okay and I'll show you a specific + + + align:start position:0% +okay and I'll show you a specific +example of that later + + align:start position:0% +example of that later + + + align:start position:0% +example of that later +on now last time we said that the + + align:start position:0% +on now last time we said that the + + + align:start position:0% +on now last time we said that the +ribosomal RNA sequences consist really + + align:start position:0% +ribosomal RNA sequences consist really + + + align:start position:0% +ribosomal RNA sequences consist really +like all Gene sequences in fact of + + align:start position:0% +like all Gene sequences in fact of + + + align:start position:0% +like all Gene sequences in fact of +several we identified several stretches + + align:start position:0% +several we identified several stretches + + + align:start position:0% +several we identified several stretches +of nucleotides types of stretches that + + align:start position:0% +of nucleotides types of stretches that + + + align:start position:0% +of nucleotides types of stretches that +can be found we said the a type + + align:start position:0% +can be found we said the a type + + + align:start position:0% +can be found we said the a type +stretches and B type stretches that are + + align:start position:0% +stretches and B type stretches that are + + + align:start position:0% +stretches and B type stretches that are +very important for constructing + + align:start position:0% +very important for constructing + + + align:start position:0% +very important for constructing +philogenetic relationship ships because + + align:start position:0% +philogenetic relationship ships because + + + align:start position:0% +philogenetic relationship ships because +we can align them and look for changes + + align:start position:0% +we can align them and look for changes + + + align:start position:0% +we can align them and look for changes +in the nucleotide sequences because um + + align:start position:0% +in the nucleotide sequences because um + + + align:start position:0% +in the nucleotide sequences because um +they're of the same length and only + + align:start position:0% +they're of the same length and only + + + align:start position:0% +they're of the same length and only +differ in um mutations and in single + + align:start position:0% +differ in um mutations and in single + + + align:start position:0% +differ in um mutations and in single +nucleotide uh base pair + + align:start position:0% +nucleotide uh base pair + + + align:start position:0% +nucleotide uh base pair +changes but then there's also those C + + align:start position:0% +changes but then there's also those C + + + align:start position:0% +changes but then there's also those C +type stretches if you remember and those + + align:start position:0% +type stretches if you remember and those + + + align:start position:0% +type stretches if you remember and those +we said vary at much faster rates + + align:start position:0% +we said vary at much faster rates + + + align:start position:0% +we said vary at much faster rates +because they are not functionally + + align:start position:0% +because they are not functionally + + + align:start position:0% +because they are not functionally +constrained in those genes okay so they + + align:start position:0% +constrained in those genes okay so they + + + align:start position:0% +constrained in those genes okay so they +can actually also accumulate um length + + align:start position:0% +can actually also accumulate um length + + + align:start position:0% +can actually also accumulate um length +changes and it's these C type stretches + + align:start position:0% +changes and it's these C type stretches + + + align:start position:0% +changes and it's these C type stretches +that we can use sort of as diagnostic + + align:start position:0% +that we can use sort of as diagnostic + + + align:start position:0% +that we can use sort of as diagnostic +sequence stretches for + + align:start position:0% +sequence stretches for + + + align:start position:0% +sequence stretches for +microorganisms so what we can say is we + + align:start position:0% + + + + align:start position:0% + +identify + + align:start position:0% + + + + align:start position:0% + +organisms by the C type stretches + + align:start position:0% + + + + align:start position:0% + +ctype sequence + + align:start position:0% + + + + align:start position:0% + +stretches we call those signature + + align:start position:0% + + + + align:start position:0% + +sequences + + align:start position:0% +sequences + + + align:start position:0% +sequences +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +okay and they + + align:start position:0% +okay and they + + + align:start position:0% +okay and they +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +allow the differentiation + + align:start position:0% + + + + align:start position:0% + +of closely related + + align:start position:0% + + + + align:start position:0% + +organisms because they vary at very fast + + align:start position:0% +organisms because they vary at very fast + + + align:start position:0% +organisms because they vary at very fast +rates between + + align:start position:0% +rates between + + + align:start position:0% +rates between +organisms and the way we do this is we + + align:start position:0% +organisms and the way we do this is we + + + align:start position:0% +organisms and the way we do this is we +construct so-called philogenetic + + align:start position:0% +construct so-called philogenetic + + + align:start position:0% +construct so-called philogenetic +probes I should probably write this over + + align:start position:0% +probes I should probably write this over + + + align:start position:0% +probes I should probably write this over +here + + align:start position:0% + + + + align:start position:0% + +now what are those philogenetic probes + + align:start position:0% +now what are those philogenetic probes + + + align:start position:0% +now what are those philogenetic probes +they're basically short pieces of + + align:start position:0% +they're basically short pieces of + + + align:start position:0% +they're basically short pieces of +DNA that have a fluorescent molecule + + align:start position:0% +DNA that have a fluorescent molecule + + + align:start position:0% +DNA that have a fluorescent molecule +attached to them + + align:start position:0% + + + + align:start position:0% + +DNA + + align:start position:0% + + + + align:start position:0% + +molecules that are roughly 20 + + align:start position:0% +molecules that are roughly 20 + + + align:start position:0% +molecules that are roughly 20 +nucleotides in + + align:start position:0% + + + + align:start position:0% + +length and they carry a + + align:start position:0% + + + + align:start position:0% + +fluorescent + + align:start position:0% + + + + align:start position:0% + +molecule now what these short single + + align:start position:0% +molecule now what these short single + + + align:start position:0% +molecule now what these short single +stranded stretches of DNA basically are + + align:start position:0% +stranded stretches of DNA basically are + + + align:start position:0% +stranded stretches of DNA basically are +is they are complementary + + align:start position:0% +is they are complementary + + + align:start position:0% +is they are complementary +to those ctype sequence + + align:start position:0% + + + + align:start position:0% + +stretches in the ribosomal + + align:start position:0% + + + + align:start position:0% + +R and so basically what we can do is we + + align:start position:0% +R and so basically what we can do is we + + + align:start position:0% +R and so basically what we can do is we +can + + align:start position:0% +can + + + align:start position:0% +can +collect microbial cells from the + + align:start position:0% +collect microbial cells from the + + + align:start position:0% +collect microbial cells from the +environment + + align:start position:0% + + + + align:start position:0% + +make them permeable + + align:start position:0% + + + + align:start position:0% + +and then basically mix them with those + + align:start position:0% +and then basically mix them with those + + + align:start position:0% +and then basically mix them with those +philogenetic + + align:start position:0% + + + + align:start position:0% + +probes and these probes will then + + align:start position:0% +probes and these probes will then + + + align:start position:0% +probes and these probes will then +permeate into the cell and bind to their + + align:start position:0% +permeate into the cell and bind to their + + + align:start position:0% +permeate into the cell and bind to their +complimentary sequences + + align:start position:0% + + + + align:start position:0% + +then we wash away the Unbound probe + + align:start position:0% + + + + align:start position:0% + +and we can view it in a microscope under + + align:start position:0% +and we can view it in a microscope under + + + align:start position:0% +and we can view it in a microscope under +UV light + + align:start position:0% + + + + align:start position:0% + +okay let me show you an example of + + align:start position:0% + + + + align:start position:0% + +this what you see here basically is + + align:start position:0% +this what you see here basically is + + + align:start position:0% +this what you see here basically is +a light micrograph so this is what you + + align:start position:0% +a light micrograph so this is what you + + + align:start position:0% +a light micrograph so this is what you +see basically when you collect microbial + + align:start position:0% +see basically when you collect microbial + + + align:start position:0% +see basically when you collect microbial +cells from the environment under the + + align:start position:0% +cells from the environment under the + + + align:start position:0% +cells from the environment under the +microscope most bacteria look the same + + align:start position:0% +microscope most bacteria look the same + + + align:start position:0% +microscope most bacteria look the same +so you cannot actually differentiate + + align:start position:0% +so you cannot actually differentiate + + + align:start position:0% +so you cannot actually differentiate +them at all by just looking at them now + + align:start position:0% +them at all by just looking at them now + + + align:start position:0% +them at all by just looking at them now +but then these cells were fixed and + + align:start position:0% +but then these cells were fixed and + + + align:start position:0% +but then these cells were fixed and +permeabilized and then basically mixed + + align:start position:0% +permeabilized and then basically mixed + + + align:start position:0% +permeabilized and then basically mixed +with two different philogenetic probes + + align:start position:0% +with two different philogenetic probes + + + align:start position:0% +with two different philogenetic probes +that identified two two different types + + align:start position:0% +that identified two two different types + + + align:start position:0% +that identified two two different types +of + + align:start position:0% +of + + + align:start position:0% +of +organisms one was AED with a red FL the + + align:start position:0% +organisms one was AED with a red FL the + + + align:start position:0% +organisms one was AED with a red FL the +other one with a green + + align:start position:0% +other one with a green + + + align:start position:0% +other one with a green +FL and what you see is that you can now + + align:start position:0% +FL and what you see is that you can now + + + align:start position:0% +FL and what you see is that you can now +differentiate those two + + align:start position:0% +differentiate those two + + + align:start position:0% +differentiate those two +organisms now why is this actually + + align:start position:0% +organisms now why is this actually + + + align:start position:0% +organisms now why is this actually +interesting well this here is just a + + align:start position:0% +interesting well this here is just a + + + align:start position:0% +interesting well this here is just a +specific + + align:start position:0% +specific + + + align:start position:0% +specific +example um where people were looking for + + align:start position:0% + + + + align:start position:0% + +um bacteria + + align:start position:0% + + + + align:start position:0% + +capable of + + align:start position:0% + + + + align:start position:0% + +nitrogen + + align:start position:0% + + + + align:start position:0% + +oxidation these are bacteria that are + + align:start position:0% +oxidation these are bacteria that are + + + align:start position:0% +oxidation these are bacteria that are +very important in for example sewage + + align:start position:0% +very important in for example sewage + + + align:start position:0% +very important in for example sewage +treatment and it's it was known already + + align:start position:0% +treatment and it's it was known already + + + align:start position:0% +treatment and it's it was known already +that there's two different types out + + align:start position:0% + + + + align:start position:0% + +there one that oxidizes ammonia + + align:start position:0% + + + + align:start position:0% + +to + + align:start position:0% + + + + align:start position:0% + +nitrite and then a second one that + + align:start position:0% +nitrite and then a second one that + + + align:start position:0% +nitrite and then a second one that +oxidizes nitrite to + + align:start position:0% + + + + align:start position:0% + +nitrate and by doing this type of + + align:start position:0% +nitrate and by doing this type of + + + align:start position:0% +nitrate and by doing this type of +analysis what people basically Learned + + align:start position:0% +analysis what people basically Learned + + + align:start position:0% +analysis what people basically Learned +was that those two organisms live in + + align:start position:0% +was that those two organisms live in + + + align:start position:0% +was that those two organisms live in +very very close proximity at all times + + align:start position:0% +very very close proximity at all times + + + align:start position:0% +very very close proximity at all times +so the organisms that oxidize ammonia to + + align:start position:0% +so the organisms that oxidize ammonia to + + + align:start position:0% +so the organisms that oxidize ammonia to +nitrite are really attached and + + align:start position:0% +nitrite are really attached and + + + align:start position:0% +nitrite are really attached and +oftentimes even surround the organisms + + align:start position:0% +oftentimes even surround the organisms + + + align:start position:0% +oftentimes even surround the organisms +that take the nitrite to nitrate so what + + align:start position:0% +that take the nitrite to nitrate so what + + + align:start position:0% +that take the nitrite to nitrate so what +you have is a very close cooperation + + align:start position:0% +you have is a very close cooperation + + + align:start position:0% +you have is a very close cooperation +between two different types of + + align:start position:0% +between two different types of + + + align:start position:0% +between two different types of +microorganisms and a transfer of one of + + align:start position:0% +microorganisms and a transfer of one of + + + align:start position:0% +microorganisms and a transfer of one of +the substrates um that's a product of + + align:start position:0% +the substrates um that's a product of + + + align:start position:0% +the substrates um that's a product of +the metabolism of one of the organisms + + align:start position:0% +the metabolism of one of the organisms + + + align:start position:0% +the metabolism of one of the organisms +to another one so an extremely efficient + + align:start position:0% +to another one so an extremely efficient + + + align:start position:0% +to another one so an extremely efficient +process that really is very important to + + align:start position:0% +process that really is very important to + + + align:start position:0% +process that really is very important to +take into consideration when you want to + + align:start position:0% +take into consideration when you want to + + + align:start position:0% +take into consideration when you want to +understand processes like sewage + + align:start position:0% +understand processes like sewage + + + align:start position:0% +understand processes like sewage +treatment but also nitrogen um biog + + align:start position:0% +treatment but also nitrogen um biog + + + align:start position:0% +treatment but also nitrogen um biog +geochemistry in the + + align:start position:0% +geochemistry in the + + + align:start position:0% +geochemistry in the +environment any + + align:start position:0% + + + + align:start position:0% + +questions okay so um for the remainder + + align:start position:0% +questions okay so um for the remainder + + + align:start position:0% +questions okay so um for the remainder +of the + + align:start position:0% +of the + + + align:start position:0% +of the +lecture I want to talk about um genomics + + align:start position:0% + + + + align:start position:0% + +and then in particular also its + + align:start position:0% +and then in particular also its + + + align:start position:0% +and then in particular also its +application to questions of + + align:start position:0% +application to questions of + + + align:start position:0% +application to questions of +environmental + + align:start position:0% +environmental + + + align:start position:0% +environmental +microbiology and uh environmental + + align:start position:0% +microbiology and uh environmental + + + align:start position:0% +microbiology and uh environmental +science so first what I want to do is + + align:start position:0% +science so first what I want to do is + + + align:start position:0% +science so first what I want to do is +give you a little bit of a definition of + + align:start position:0% +give you a little bit of a definition of + + + align:start position:0% +give you a little bit of a definition of +um + + align:start position:0% +um + + + align:start position:0% +um +genomics then I want to cover how it is + + align:start position:0% +genomics then I want to cover how it is + + + align:start position:0% +genomics then I want to cover how it is +actually possible that we can sequence + + align:start position:0% +actually possible that we can sequence + + + align:start position:0% +actually possible that we can sequence +entire + + align:start position:0% +entire + + + align:start position:0% +entire +genomes and then I want to give you some + + align:start position:0% +genomes and then I want to give you some + + + align:start position:0% +genomes and then I want to give you some +highlights of what we have found by + + align:start position:0% +highlights of what we have found by + + + align:start position:0% +highlights of what we have found by +comparing different genomes to each + + align:start position:0% +comparing different genomes to each + + + align:start position:0% +comparing different genomes to each +other and then I want to talk about this + + align:start position:0% +other and then I want to talk about this + + + align:start position:0% +other and then I want to talk about this +field about environmental genomics where + + align:start position:0% +field about environmental genomics where + + + align:start position:0% +field about environmental genomics where +we can use genomic techniques to + + align:start position:0% +we can use genomic techniques to + + + align:start position:0% +we can use genomic techniques to +actually learn something about the + + align:start position:0% +actually learn something about the + + + align:start position:0% +actually learn something about the +function of different uncultured + + align:start position:0% +function of different uncultured + + + align:start position:0% +function of different uncultured +microorganisms in the + + align:start position:0% +microorganisms in the + + + align:start position:0% +microorganisms in the +environment so first our + + align:start position:0% + + + + align:start position:0% + +definition it's basically to interpret + + align:start position:0% +definition it's basically to interpret + + + align:start position:0% +definition it's basically to interpret +or to sequence + + align:start position:0% + + + + align:start position:0% + +interpret and + + align:start position:0% + + + + align:start position:0% + +compare whole + + align:start position:0% + + + + align:start position:0% + +genomes and as you will see the + + align:start position:0% +genomes and as you will see the + + + align:start position:0% +genomes and as you will see the +comparison part actually plays an + + align:start position:0% +comparison part actually plays an + + + align:start position:0% +comparison part actually plays an +increasingly important role because we + + align:start position:0% +increasingly important role because we + + + align:start position:0% +increasingly important role because we +have now actually genome sequences + + align:start position:0% +have now actually genome sequences + + + align:start position:0% +have now actually genome sequences +available from almost all or from at + + align:start position:0% +available from almost all or from at + + + align:start position:0% +available from almost all or from at +least some of the major groups of life + + align:start position:0% +least some of the major groups of life + + + align:start position:0% +least some of the major groups of life +so we have a lot of um this again is a a + + align:start position:0% +so we have a lot of um this again is a a + + + align:start position:0% +so we have a lot of um this again is a a +different kind of representation of a + + align:start position:0% +different kind of representation of a + + + align:start position:0% +different kind of representation of a +tree of life you have bacteria or ukaria + + align:start position:0% +tree of life you have bacteria or ukaria + + + align:start position:0% +tree of life you have bacteria or ukaria +again and as you can see we have a lot + + align:start position:0% +again and as you can see we have a lot + + + align:start position:0% +again and as you can see we have a lot +of Representatives in fact this doesn't + + align:start position:0% +of Representatives in fact this doesn't + + + align:start position:0% +of Representatives in fact this doesn't +even uh come close to the diversity that + + align:start position:0% +even uh come close to the diversity that + + + align:start position:0% +even uh come close to the diversity that +we have now sequenced there's well over + + align:start position:0% +we have now sequenced there's well over + + + align:start position:0% +we have now sequenced there's well over +100 bacterial genome sequence now + + align:start position:0% +100 bacterial genome sequence now + + + align:start position:0% +100 bacterial genome sequence now +several AR keal genomes and increasingly + + align:start position:0% +several AR keal genomes and increasingly + + + align:start position:0% +several AR keal genomes and increasingly +also UK carot genomes + + align:start position:0% +also UK carot genomes + + + align:start position:0% +also UK carot genomes +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +now + + align:start position:0% + + + + align:start position:0% + +genomes so how is this + + align:start position:0% +genomes so how is this + + + align:start position:0% +genomes so how is this +done how can we actually sequence + + align:start position:0% +done how can we actually sequence + + + align:start position:0% +done how can we actually sequence +genomes well on the face of it we use um + + align:start position:0% +genomes well on the face of it we use um + + + align:start position:0% +genomes well on the face of it we use um +very large facilities where you have uh + + align:start position:0% +very large facilities where you have uh + + + align:start position:0% +very large facilities where you have uh +sequencing machines present there's one + + align:start position:0% +sequencing machines present there's one + + + align:start position:0% +sequencing machines present there's one +very important one at MIT actually in um + + align:start position:0% +very important one at MIT actually in um + + + align:start position:0% +very important one at MIT actually in um +the broad Institute and here you see all + + align:start position:0% +the broad Institute and here you see all + + + align:start position:0% +the broad Institute and here you see all +those um really uh industrial scale + + align:start position:0% +those um really uh industrial scale + + + align:start position:0% +those um really uh industrial scale +uction lines + + align:start position:0% +uction lines + + + align:start position:0% +uction lines +actually but the problem the basic + + align:start position:0% +actually but the problem the basic + + + align:start position:0% +actually but the problem the basic +problem is that genomes are + + align:start position:0% + + + + align:start position:0% + +large eoli for + + align:start position:0% +large eoli for + + + align:start position:0% +large eoli for +example + + align:start position:0% +example + + + align:start position:0% +example +has + + align:start position:0% +has + + + align:start position:0% +has +roughly 4.4 million base + + align:start position:0% + + + + align:start position:0% + +pairs and the human genome is even even + + align:start position:0% +pairs and the human genome is even even + + + align:start position:0% +pairs and the human genome is even even +much much larger it has about 3 + + align:start position:0% + + + + align:start position:0% + +billion base pairs okay so genomes are + + align:start position:0% +billion base pairs okay so genomes are + + + align:start position:0% +billion base pairs okay so genomes are +very very large but an a single + + align:start position:0% +very very large but an a single + + + align:start position:0% +very very large but an a single +sequencing + + align:start position:0% + + + + align:start position:0% + +reaction gives you only roughly 500 to + + align:start position:0% +reaction gives you only roughly 500 to + + + align:start position:0% +reaction gives you only roughly 500 to +1,000 nucleotides or base pairs + + align:start position:0% + + + + align:start position:0% + +so how is it that we can actually + + align:start position:0% +so how is it that we can actually + + + align:start position:0% +so how is it that we can actually +sequence um entire + + align:start position:0% +sequence um entire + + + align:start position:0% +sequence um entire +genomes I want to walk you through this + + align:start position:0% +genomes I want to walk you through this + + + align:start position:0% +genomes I want to walk you through this +and there's some variations on the theme + + align:start position:0% +and there's some variations on the theme + + + align:start position:0% +and there's some variations on the theme +but um this is still um sort of a major + + align:start position:0% +but um this is still um sort of a major + + + align:start position:0% +but um this is still um sort of a major +uh approach that's still used in in some + + align:start position:0% +uh approach that's still used in in some + + + align:start position:0% +uh approach that's still used in in some +of in in a majority of the sequencing + + align:start position:0% +of in in a majority of the sequencing + + + align:start position:0% +of in in a majority of the sequencing +facilities now you start out by + + align:start position:0% +facilities now you start out by + + + align:start position:0% +facilities now you start out by +extracting genomic DNA from organisms + + align:start position:0% +extracting genomic DNA from organisms + + + align:start position:0% +extracting genomic DNA from organisms +and then you use restriction enzymes to + + align:start position:0% +and then you use restriction enzymes to + + + align:start position:0% +and then you use restriction enzymes to +cut the DNA into relatively large pieces + + align:start position:0% +cut the DNA into relatively large pieces + + + align:start position:0% +cut the DNA into relatively large pieces +of DNA so about 160 kilobase pairs long + + align:start position:0% +of DNA so about 160 kilobase pairs long + + + align:start position:0% +of DNA so about 160 kilobase pairs long +on average as is shown here now kilo + + align:start position:0% +on average as is shown here now kilo + + + align:start position:0% +on average as is shown here now kilo +means a th000 so 160,000 base pairs + + align:start position:0% + + + + align:start position:0% + +long these pieces are then cloned into + + align:start position:0% +long these pieces are then cloned into + + + align:start position:0% +long these pieces are then cloned into +specific clone vectors that are called + + align:start position:0% +specific clone vectors that are called + + + align:start position:0% +specific clone vectors that are called +back + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% + + + + align:start position:0% + +vectors so therefore + + align:start position:0% + + + + align:start position:0% + +cloning large pieces of + + align:start position:0% + + + + align:start position:0% + +DNA and back stands for + + align:start position:0% + + + + align:start position:0% + +bacterial artificial + + align:start position:0% + + + + align:start position:0% + +chromosome and what they basically are + + align:start position:0% +chromosome and what they basically are + + + align:start position:0% +chromosome and what they basically are +are + + align:start position:0% + + + + align:start position:0% + +plasmids very special + + align:start position:0% +plasmids very special + + + align:start position:0% +plasmids very special +plasmids that can carry + + align:start position:0% + + + + align:start position:0% + +large pieces of genome or large genome + + align:start position:0% + + + + align:start position:0% + +fragments so by cloning into those back + + align:start position:0% +fragments so by cloning into those back + + + align:start position:0% +fragments so by cloning into those back +vectors what you do is you basically + + align:start position:0% +vectors what you do is you basically + + + align:start position:0% +vectors what you do is you basically +divide up the + + align:start position:0% +divide up the + + + align:start position:0% +divide up the +genome and you can then this is Step + + align:start position:0% +genome and you can then this is Step + + + align:start position:0% +genome and you can then this is Step +number three is mostly done for um UK + + align:start position:0% +number three is mostly done for um UK + + + align:start position:0% +number three is mostly done for um UK +carotic genomes because they're so much + + align:start position:0% +carotic genomes because they're so much + + + align:start position:0% +carotic genomes because they're so much +larger you can actually map then those + + align:start position:0% +larger you can actually map then those + + + align:start position:0% +larger you can actually map then those +uh analyze the fragments in map and onto + + align:start position:0% +uh analyze the fragments in map and onto + + + align:start position:0% +uh analyze the fragments in map and onto +maps onto uh genome Maps where you know + + align:start position:0% +maps onto uh genome Maps where you know + + + align:start position:0% +maps onto uh genome Maps where you know +the location of different um restriction + + align:start position:0% +the location of different um restriction + + + align:start position:0% +the location of different um restriction +fragments and different uh genes + + align:start position:0% +fragments and different uh genes + + + align:start position:0% +fragments and different uh genes +actually for bacteria this step is + + align:start position:0% +actually for bacteria this step is + + + align:start position:0% +actually for bacteria this step is +mostly skipped + + align:start position:0% +mostly skipped + + + align:start position:0% +mostly skipped +actually what you do then with each one + + align:start position:0% +actually what you do then with each one + + + align:start position:0% +actually what you do then with each one +of those bags is you cut them further up + + align:start position:0% +of those bags is you cut them further up + + + align:start position:0% +of those bags is you cut them further up +into one kilobase per fragment so + + align:start position:0% +into one kilobase per fragment so + + + align:start position:0% +into one kilobase per fragment so +smaller much smaller fragments and these + + align:start position:0% +smaller much smaller fragments and these + + + align:start position:0% +smaller much smaller fragments and these +are called + + align:start position:0% +are called + + + align:start position:0% +are called +um and this is then actually these are + + align:start position:0% +um and this is then actually these are + + + align:start position:0% +um and this is then actually these are +clone then into normal plasmid vectors + + align:start position:0% +clone then into normal plasmid vectors + + + align:start position:0% +clone then into normal plasmid vectors +and so you generate what is called + + align:start position:0% +and so you generate what is called + + + align:start position:0% +and so you generate what is called +shotgun + + align:start position:0% +shotgun + + + align:start position:0% +shotgun +clones so these are then cloned into + + align:start position:0% +clones so these are then cloned into + + + align:start position:0% +clones so these are then cloned into +Eola and basically you go through the + + align:start position:0% +Eola and basically you go through the + + + align:start position:0% +Eola and basically you go through the +same type of steps that we discussed uh + + align:start position:0% +same type of steps that we discussed uh + + + align:start position:0% +same type of steps that we discussed uh +before already with environmental clone + + align:start position:0% +before already with environmental clone + + + align:start position:0% +before already with environmental clone +libraries and you can actually determine + + align:start position:0% +libraries and you can actually determine + + + align:start position:0% +libraries and you can actually determine +the sequence of each one of those pieces + + align:start position:0% +the sequence of each one of those pieces + + + align:start position:0% +the sequence of each one of those pieces +of DNA and what you will then get is + + align:start position:0% +of DNA and what you will then get is + + + align:start position:0% +of DNA and what you will then get is +small fragments of overlapping DNA + + align:start position:0% +small fragments of overlapping DNA + + + align:start position:0% +small fragments of overlapping DNA +sequence okay + + align:start position:0% + + + + align:start position:0% + +that is shown here and you will find + + align:start position:0% +that is shown here and you will find + + + align:start position:0% +that is shown here and you will find +overlaps basically which you piece + + align:start position:0% +overlaps basically which you piece + + + align:start position:0% +overlaps basically which you piece +together the whole + + align:start position:0% + + + + align:start position:0% + +genome and so first you assemble you + + align:start position:0% +genome and so first you assemble you + + + align:start position:0% +genome and so first you assemble you +piece together those large genome + + align:start position:0% +piece together those large genome + + + align:start position:0% +piece together those large genome +fragments that are present in the backs + + align:start position:0% +fragments that are present in the backs + + + align:start position:0% +fragments that are present in the backs +and then finally you piece together the + + align:start position:0% +and then finally you piece together the + + + align:start position:0% +and then finally you piece together the +entire genome um from those large + + align:start position:0% +entire genome um from those large + + + align:start position:0% +entire genome um from those large +sequence pieces and you get a so-called + + align:start position:0% +sequence pieces and you get a so-called + + + align:start position:0% +sequence pieces and you get a so-called +draft genome sequence + + align:start position:0% +draft genome sequence + + + align:start position:0% +draft genome sequence +the next step in this analysis then is + + align:start position:0% +the next step in this analysis then is + + + align:start position:0% +the next step in this analysis then is +that + + align:start position:0% +that + + + align:start position:0% +that +you + + align:start position:0% + + + + align:start position:0% + +um do so-called genome + + align:start position:0% + + + + align:start position:0% + +anotation and the first very important + + align:start position:0% +anotation and the first very important + + + align:start position:0% +anotation and the first very important +step is that you translate the um Gene + + align:start position:0% +step is that you translate the um Gene + + + align:start position:0% +step is that you translate the um Gene +sequences into Amino + + align:start position:0% +sequences into Amino + + + align:start position:0% +sequences into Amino +acids so the nucleotide sequence is into + + align:start position:0% +acids so the nucleotide sequence is into + + + align:start position:0% +acids so the nucleotide sequence is into +amino acids particularly in + + align:start position:0% + + + + align:start position:0% + +procaryotes this step can be done um + + align:start position:0% +procaryotes this step can be done um + + + align:start position:0% +procaryotes this step can be done um +right away + + align:start position:0% + + + + align:start position:0% + +and what this allows you to do is you + + align:start position:0% +and what this allows you to do is you + + + align:start position:0% +and what this allows you to do is you +can look for um what we call open + + align:start position:0% +can look for um what we call open + + + align:start position:0% +can look for um what we call open +reading frames or + + align:start position:0% +reading frames or + + + align:start position:0% +reading frames or +ORS and what you look for is a start + + align:start position:0% +ORS and what you look for is a start + + + align:start position:0% +ORS and what you look for is a start +codon and a stop codon that basically + + align:start position:0% +codon and a stop codon that basically + + + align:start position:0% +codon and a stop codon that basically +branches um or frames a stretch of amino + + align:start position:0% +branches um or frames a stretch of amino + + + align:start position:0% +branches um or frames a stretch of amino +acids encoded by the + + align:start position:0% + + + + align:start position:0% + +nucleotides so you + + align:start position:0% +nucleotides so you + + + align:start position:0% +nucleotides so you +look for ORS + + align:start position:0% + + + + align:start position:0% + +and these are your putative + + align:start position:0% + + + + align:start position:0% + +genes The Next Step that you can do then + + align:start position:0% +genes The Next Step that you can do then + + + align:start position:0% +genes The Next Step that you can do then +is that you go to databases + + align:start position:0% + + + + align:start position:0% + +and now you compare your ORS to + + align:start position:0% +and now you compare your ORS to + + + align:start position:0% +and now you compare your ORS to +information that is present in the + + align:start position:0% +information that is present in the + + + align:start position:0% +information that is present in the +databases so basically you inquire the + + align:start position:0% +databases so basically you inquire the + + + align:start position:0% +databases so basically you inquire the +database uh and ask is a gene sequence + + align:start position:0% +database uh and ask is a gene sequence + + + align:start position:0% +database uh and ask is a gene sequence +that is similar to the one that I have + + align:start position:0% +that is similar to the one that I have + + + align:start position:0% +that is similar to the one that I have +statistically significantly similar + + align:start position:0% +statistically significantly similar + + + align:start position:0% +statistically significantly similar +present that allows me to say something + + align:start position:0% +present that allows me to say something + + + align:start position:0% +present that allows me to say something +about the function of this particular + + align:start position:0% + + + + align:start position:0% + +Gene so + + align:start position:0% + + + + align:start position:0% + +function can be + + align:start position:0% + + + + align:start position:0% + +identified by comparison with + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% + + + + align:start position:0% + +databases that's + + align:start position:0% +databases that's + + + align:start position:0% +databases that's +the any + + align:start position:0% + + + + align:start position:0% + +questions okay so and that allows you + + align:start position:0% +questions okay so and that allows you + + + align:start position:0% +questions okay so and that allows you +then basically to um say something uh + + align:start position:0% +then basically to um say something uh + + + align:start position:0% +then basically to um say something uh +about the different genes that are that + + align:start position:0% +about the different genes that are that + + + align:start position:0% +about the different genes that are that +you have found in a genome but to give + + align:start position:0% +you have found in a genome but to give + + + align:start position:0% +you have found in a genome but to give +you an impression of how new this field + + align:start position:0% +you an impression of how new this field + + + align:start position:0% +you an impression of how new this field +really is and how little we still know + + align:start position:0% +really is and how little we still know + + + align:start position:0% +really is and how little we still know +about the diversity of genes in + + align:start position:0% +about the diversity of genes in + + + align:start position:0% +about the diversity of genes in +organisms on average when we sequence a + + align:start position:0% +organisms on average when we sequence a + + + align:start position:0% +organisms on average when we sequence a +new bacterial genome we find about 30% + + align:start position:0% +new bacterial genome we find about 30% + + + align:start position:0% +new bacterial genome we find about 30% +of the genes so a third of the genes + + align:start position:0% +of the genes so a third of the genes + + + align:start position:0% +of the genes so a third of the genes +have no known functional analog in the + + align:start position:0% +have no known functional analog in the + + + align:start position:0% +have no known functional analog in the +databases okay so there's a lot to learn + + align:start position:0% +databases okay so there's a lot to learn + + + align:start position:0% +databases okay so there's a lot to learn +about the diversity of life and about + + align:start position:0% +about the diversity of life and about + + + align:start position:0% +about the diversity of life and about +the functional diversity of life + + align:start position:0% +the functional diversity of life + + + align:start position:0% +the functional diversity of life +okay in UK carots there's a little twist + + align:start position:0% +okay in UK carots there's a little twist + + + align:start position:0% +okay in UK carots there's a little twist +as you all + + align:start position:0% + + + + align:start position:0% + +know and basically that is that genes of + + align:start position:0% +know and basically that is that genes of + + + align:start position:0% +know and basically that is that genes of +course consist of introns and exons + + align:start position:0% +course consist of introns and exons + + + align:start position:0% +course consist of introns and exons +right + + align:start position:0% + + + + align:start position:0% + +and so it's basically relatively + + align:start position:0% +and so it's basically relatively + + + align:start position:0% +and so it's basically relatively +difficult to directly identify those + + align:start position:0% +difficult to directly identify those + + + align:start position:0% +difficult to directly identify those +open reading + + align:start position:0% +open reading + + + align:start position:0% +open reading +frames and what you have to do is that + + align:start position:0% +frames and what you have to do is that + + + align:start position:0% +frames and what you have to do is that +you have to actually often times so + + align:start position:0% +you have to actually often times so + + + align:start position:0% +you have to actually often times so +let's write this + + align:start position:0% + + + + align:start position:0% + +down and what people often times do then + + align:start position:0% +down and what people often times do then + + + align:start position:0% +down and what people often times do then +is that that they + + align:start position:0% + + + + align:start position:0% + +search for matching + + align:start position:0% + + + + align:start position:0% + +sequences in so-called cdna + + align:start position:0% + + + + align:start position:0% + +libraries now what are cdna libraries + + align:start position:0% +libraries now what are cdna libraries + + + align:start position:0% +libraries now what are cdna libraries +let me just show you this on the next + + align:start position:0% +let me just show you this on the next + + + align:start position:0% +let me just show you this on the next +slide skip this + + align:start position:0% +slide skip this + + + align:start position:0% +slide skip this +basically what you can do is you can + + align:start position:0% +basically what you can do is you can + + + align:start position:0% +basically what you can do is you can +isolate messenger RNA from cells and + + align:start position:0% +isolate messenger RNA from cells and + + + align:start position:0% +isolate messenger RNA from cells and +then + + align:start position:0% +then + + + align:start position:0% +then +translate this messenger RNA by a + + align:start position:0% +translate this messenger RNA by a + + + align:start position:0% +translate this messenger RNA by a +process called reverse transcription + + align:start position:0% +process called reverse transcription + + + align:start position:0% +process called reverse transcription +that's a viral enzyme that translates + + align:start position:0% +that's a viral enzyme that translates + + + align:start position:0% +that's a viral enzyme that translates +RNA into DNA so you can translate it + + align:start position:0% +RNA into DNA so you can translate it + + + align:start position:0% +RNA into DNA so you can translate it +into DNA fragments and you can then + + align:start position:0% +into DNA fragments and you can then + + + align:start position:0% +into DNA fragments and you can then +clone those DNA fragments into plasmids + + align:start position:0% +clone those DNA fragments into plasmids + + + align:start position:0% +clone those DNA fragments into plasmids +sequence those and then basically see + + align:start position:0% +sequence those and then basically see + + + align:start position:0% +sequence those and then basically see +what + + align:start position:0% +what + + + align:start position:0% +what +are the pieces that are actually um what + + align:start position:0% +are the pieces that are actually um what + + + align:start position:0% +are the pieces that are actually um what +are the inance in the genes what are the + + align:start position:0% +are the inance in the genes what are the + + + align:start position:0% +are the inance in the genes what are the +pieces that are excised um when the + + align:start position:0% +pieces that are excised um when the + + + align:start position:0% +pieces that are excised um when the +messenger RNA is actually created uh + + align:start position:0% +messenger RNA is actually created uh + + + align:start position:0% +messenger RNA is actually created uh +from uh the genome + + align:start position:0% + + + + align:start position:0% + +so let me just cover now a few of the + + align:start position:0% +so let me just cover now a few of the + + + align:start position:0% +so let me just cover now a few of the +major insights that people have come up + + align:start position:0% +major insights that people have come up + + + align:start position:0% +major insights that people have come up +with of course it's a + + align:start position:0% +with of course it's a + + + align:start position:0% +with of course it's a +very uh growing field and a lot of + + align:start position:0% +very uh growing field and a lot of + + + align:start position:0% +very uh growing field and a lot of +excitement is is coming + + align:start position:0% + + + + align:start position:0% + +out and I first want to talk about + + align:start position:0% +out and I first want to talk about + + + align:start position:0% +out and I first want to talk about +bacteria and + + align:start position:0% + + + + align:start position:0% + +ARA and then say a few words also about + + align:start position:0% +ARA and then say a few words also about + + + align:start position:0% +ARA and then say a few words also about +ukari or + + align:start position:0% +ukari or + + + align:start position:0% +ukari or +ukaria first of all what we learned + + align:start position:0% +ukaria first of all what we learned + + + align:start position:0% +ukaria first of all what we learned +about bacteria and ARA is that their + + align:start position:0% +about bacteria and ARA is that their + + + align:start position:0% +about bacteria and ARA is that their +genomes are very compact + + align:start position:0% + + + + align:start position:0% + +whenever they have pieces of DNA that + + align:start position:0% +whenever they have pieces of DNA that + + + align:start position:0% +whenever they have pieces of DNA that +are not frequently used they're actually + + align:start position:0% +are not frequently used they're actually + + + align:start position:0% +are not frequently used they're actually +lost from The genome okay so they lose + + align:start position:0% +lost from The genome okay so they lose + + + align:start position:0% +lost from The genome okay so they lose +genomes or genes I should say uh + + align:start position:0% +genomes or genes I should say uh + + + align:start position:0% +genomes or genes I should say uh +relatively easily and we can see + + align:start position:0% + + + + align:start position:0% + +this that the genome size excuse + + align:start position:0% + + + + align:start position:0% + +me is correlated + + align:start position:0% + + + + align:start position:0% + +to metabolic + + align:start position:0% + + + + align:start position:0% + +diversity so for + + align:start position:0% +diversity so for + + + align:start position:0% +diversity so for +example with + + align:start position:0% + + + + align:start position:0% + +microplasma + + align:start position:0% + + + + align:start position:0% + +genitalium and streptococus uh excuse me + + align:start position:0% +genitalium and streptococus uh excuse me + + + align:start position:0% +genitalium and streptococus uh excuse me +strepto + + align:start position:0% + + + + align:start position:0% + +misis + + align:start position:0% +misis + + + align:start position:0% +misis +celic are two very different bacteria + + align:start position:0% +celic are two very different bacteria + + + align:start position:0% +celic are two very different bacteria +the first one is an obligate + + align:start position:0% +the first one is an obligate + + + align:start position:0% +the first one is an obligate +intracellular parasite + + align:start position:0% + + + + align:start position:0% + +okay so which means it's actually based + + align:start position:0% +okay so which means it's actually based + + + align:start position:0% +okay so which means it's actually based +in a nutrient solution in the eukariotic + + align:start position:0% +in a nutrient solution in the eukariotic + + + align:start position:0% +in a nutrient solution in the eukariotic +cells that it invades it doesn't have to + + align:start position:0% +cells that it invades it doesn't have to + + + align:start position:0% +cells that it invades it doesn't have to +make amino acids it gets it just from + + align:start position:0% +make amino acids it gets it just from + + + align:start position:0% +make amino acids it gets it just from +the host cell and it turns out it has a + + align:start position:0% +the host cell and it turns out it has a + + + align:start position:0% +the host cell and it turns out it has a +very small + + align:start position:0% +very small + + + align:start position:0% +very small +genome so only + + align:start position:0% +genome so only + + + align:start position:0% +genome so only +.58 megabase pairs so um 580,000 base + + align:start position:0% +.58 megabase pairs so um 580,000 base + + + align:start position:0% +.58 megabase pairs so um 580,000 base +Pairs and only 5177 + + align:start position:0% + + + + align:start position:0% + +genes and interestingly actually people + + align:start position:0% +genes and interestingly actually people + + + align:start position:0% +genes and interestingly actually people +are now using this organism to try and + + align:start position:0% +are now using this organism to try and + + + align:start position:0% +are now using this organism to try and +ask well what's the minimum number of + + align:start position:0% +ask well what's the minimum number of + + + align:start position:0% +ask well what's the minimum number of +genes that an organism can actually live + + align:start position:0% +genes that an organism can actually live + + + align:start position:0% +genes that an organism can actually live +with and so they're + + align:start position:0% +with and so they're + + + align:start position:0% +with and so they're +deleting in a stepwise fashion the + + align:start position:0% +deleting in a stepwise fashion the + + + align:start position:0% +deleting in a stepwise fashion the +different genes in this organism and it + + align:start position:0% +different genes in this organism and it + + + align:start position:0% +different genes in this organism and it +turns out that um you need about two to + + align:start position:0% +turns out that um you need about two to + + + align:start position:0% +turns out that um you need about two to +300 genes minimum um in order to uh make + + align:start position:0% +300 genes minimum um in order to uh make + + + align:start position:0% +300 genes minimum um in order to uh make +the things uh to + + align:start position:0% +the things uh to + + + align:start position:0% +the things uh to +survive on the other hand streptomyces + + align:start position:0% +survive on the other hand streptomyces + + + align:start position:0% +survive on the other hand streptomyces +is a soil + + align:start position:0% + + + + align:start position:0% + +bacterium has a very complex lifestyle + + align:start position:0% +bacterium has a very complex lifestyle + + + align:start position:0% +bacterium has a very complex lifestyle +can degrade um a lot of uh environmental + + align:start position:0% +can degrade um a lot of uh environmental + + + align:start position:0% +can degrade um a lot of uh environmental +substrates and it has a very big genome + + align:start position:0% +substrates and it has a very big genome + + + align:start position:0% +substrates and it has a very big genome +one of the biggest bacterial genomes and + + align:start position:0% +one of the biggest bacterial genomes and + + + align:start position:0% +one of the biggest bacterial genomes and +so those two or organisms basically span + + align:start position:0% +so those two or organisms basically span + + + align:start position:0% +so those two or organisms basically span +pretty much the + + align:start position:0% +pretty much the + + + align:start position:0% +pretty much the +um the the range of bacterial genome + + align:start position:0% +um the the range of bacterial genome + + + align:start position:0% +um the the range of bacterial genome +sizes and so it's thought that it has + + align:start position:0% +sizes and so it's thought that it has + + + align:start position:0% +sizes and so it's thought that it has +about + + align:start position:0% +about + + + align:start position:0% +about +7,846 + + align:start position:0% + + + + align:start position:0% + +genes + + align:start position:0% +genes + + + align:start position:0% +genes +okay now we also have have a very large + + align:start position:0% +okay now we also have have a very large + + + align:start position:0% +okay now we also have have a very large +genetic + + align:start position:0% + + + + align:start position:0% + +diversity between + + align:start position:0% + + + + align:start position:0% + +species and typically what you find is + + align:start position:0% +species and typically what you find is + + + align:start position:0% +species and typically what you find is +that roughly 15 to 30% of + + align:start position:0% + + + + align:start position:0% + +genes are + + align:start position:0% + + + + align:start position:0% + +unique to a spefic specific + + align:start position:0% + + + + align:start position:0% + +species and that's really because + + align:start position:0% +species and that's really because + + + align:start position:0% +species and that's really because +bacteria and + + align:start position:0% +bacteria and + + + align:start position:0% +bacteria and +ARA have the capability to um affect a + + align:start position:0% +ARA have the capability to um affect a + + + align:start position:0% +ARA have the capability to um affect a +lot of chemical reactions that UK carots + + align:start position:0% +lot of chemical reactions that UK carots + + + align:start position:0% +lot of chemical reactions that UK carots +for example cannot there's about um 20 + + align:start position:0% +for example cannot there's about um 20 + + + align:start position:0% +for example cannot there's about um 20 +million known organic substances organic + + align:start position:0% +million known organic substances organic + + + align:start position:0% +million known organic substances organic +chemicals and almost all of them are + + align:start position:0% +chemicals and almost all of them are + + + align:start position:0% +chemicals and almost all of them are +biodegradable by bacteria okay even the + + align:start position:0% +biodegradable by bacteria okay even the + + + align:start position:0% +biodegradable by bacteria okay even the +my + + align:start position:0% +my + + + align:start position:0% +my +nudist compound uh if it were not + + align:start position:0% +nudist compound uh if it were not + + + align:start position:0% +nudist compound uh if it were not +biodegradable by bacteria would build up + + align:start position:0% +biodegradable by bacteria would build up + + + align:start position:0% +biodegradable by bacteria would build up +in the environment okay so if it just + + align:start position:0% +in the environment okay so if it just + + + align:start position:0% +in the environment okay so if it just +were a co-actor that some organism + + align:start position:0% +were a co-actor that some organism + + + align:start position:0% +were a co-actor that some organism +produces because we have such a long + + align:start position:0% +produces because we have such a long + + + align:start position:0% +produces because we have such a long +period of time of evolution on this + + align:start position:0% +period of time of evolution on this + + + align:start position:0% +period of time of evolution on this +planet um and evolutionary history it + + align:start position:0% +planet um and evolutionary history it + + + align:start position:0% +planet um and evolutionary history it +would you would probably be able to dig + + align:start position:0% +would you would probably be able to dig + + + align:start position:0% +would you would probably be able to dig +it up in your backyard + + align:start position:0% + + + + align:start position:0% + +one of the other very important and + + align:start position:0% +one of the other very important and + + + align:start position:0% +one of the other very important and +interesting insights that has come out + + align:start position:0% +interesting insights that has come out + + + align:start position:0% +interesting insights that has come out +of comparing + + align:start position:0% +of comparing + + + align:start position:0% +of comparing +genomes of microorganisms is that + + align:start position:0% +genomes of microorganisms is that + + + align:start position:0% +genomes of microorganisms is that +lateral Gene + + align:start position:0% + + + + align:start position:0% + +transfer is a very important process + + align:start position:0% +transfer is a very important process + + + align:start position:0% +transfer is a very important process +amongst microorganisms + + align:start position:0% + + + + align:start position:0% + +now what do we mean by a lateral Gene + + align:start position:0% +now what do we mean by a lateral Gene + + + align:start position:0% +now what do we mean by a lateral Gene +transfer it basically means that we find + + align:start position:0% +transfer it basically means that we find + + + align:start position:0% +transfer it basically means that we find +evidence amongst bacterial genomes that + + align:start position:0% +evidence amongst bacterial genomes that + + + align:start position:0% +evidence amongst bacterial genomes that +they have actually taken up genes from + + align:start position:0% +they have actually taken up genes from + + + align:start position:0% +they have actually taken up genes from +completely unrelated + + align:start position:0% +completely unrelated + + + align:start position:0% +completely unrelated +organisms and I just want to show you + + align:start position:0% +organisms and I just want to show you + + + align:start position:0% +organisms and I just want to show you +one example here that of thermatoga Mer + + align:start position:0% + + + + align:start position:0% + +which lives in Hot + + align:start position:0% + + + + align:start position:0% + +Springs this is a very interesting + + align:start position:0% +Springs this is a very interesting + + + align:start position:0% +Springs this is a very interesting +bacterium that can live in hot water of + + align:start position:0% +bacterium that can live in hot water of + + + align:start position:0% +bacterium that can live in hot water of +around 80° + + align:start position:0% +around 80° + + + align:start position:0% +around 80° +C and um um thrives only in those kinds + + align:start position:0% +C and um um thrives only in those kinds + + + align:start position:0% +C and um um thrives only in those kinds +of environments and it coexists there + + align:start position:0% +of environments and it coexists there + + + align:start position:0% +of environments and it coexists there +with many + + align:start position:0% +with many + + + align:start position:0% +with many +ARA and when people sequenced the Genome + + align:start position:0% +ARA and when people sequenced the Genome + + + align:start position:0% +ARA and when people sequenced the Genome +of thermotoga what they found was that + + align:start position:0% +of thermotoga what they found was that + + + align:start position:0% +of thermotoga what they found was that +about 25% of the genes have their + + align:start position:0% +about 25% of the genes have their + + + align:start position:0% +about 25% of the genes have their +closest relatives in archal + + align:start position:0% + + + + align:start position:0% + +genomes so roughly + + align:start position:0% + + + + align:start position:0% + +25% of genes in thermatoga are + + align:start position:0% +25% of genes in thermatoga are + + + align:start position:0% +25% of genes in thermatoga are +of + + align:start position:0% + + + + align:start position:0% + +Aral + + align:start position:0% + + + + align:start position:0% + +origin now how can we actually figure + + align:start position:0% +origin now how can we actually figure + + + align:start position:0% +origin now how can we actually figure +something like that out well the most + + align:start position:0% +something like that out well the most + + + align:start position:0% +something like that out well the most +important technique is again uh + + align:start position:0% +important technique is again uh + + + align:start position:0% +important technique is again uh +philogenetic uh tree construction and so + + align:start position:0% +philogenetic uh tree construction and so + + + align:start position:0% +philogenetic uh tree construction and so +when you have for + + align:start position:0% +when you have for + + + align:start position:0% +when you have for +example Gene + + align:start position:0% +example Gene + + + align:start position:0% +example Gene +a well let me draw this actually on a + + align:start position:0% +a well let me draw this actually on a + + + align:start position:0% +a well let me draw this actually on a +new board + + align:start position:0% + + + + align:start position:0% + +so you're comparing say three + + align:start position:0% +so you're comparing say three + + + align:start position:0% +so you're comparing say three +organisms organism a b and c and you + + align:start position:0% + + + + align:start position:0% + +compare Gene one + + align:start position:0% +compare Gene one + + + align:start position:0% +compare Gene one +with Gene two and you notice that most + + align:start position:0% +with Gene two and you notice that most + + + align:start position:0% +with Gene two and you notice that most +genes + + align:start position:0% +genes + + + align:start position:0% +genes +adhere to this pattern but then every + + align:start position:0% +adhere to this pattern but then every + + + align:start position:0% +adhere to this pattern but then every +now and then there's a gene that gives + + align:start position:0% +now and then there's a gene that gives + + + align:start position:0% +now and then there's a gene that gives +you + + align:start position:0% +you + + + align:start position:0% +you +this type of + + align:start position:0% +this type of + + + align:start position:0% +this type of +pattern what you can then conclude is + + align:start position:0% +pattern what you can then conclude is + + + align:start position:0% +pattern what you can then conclude is +that this Gene C has not co-evolved with + + align:start position:0% +that this Gene C has not co-evolved with + + + align:start position:0% +that this Gene C has not co-evolved with +the other genes in the Genome of these + + align:start position:0% +the other genes in the Genome of these + + + align:start position:0% +the other genes in the Genome of these +organisms but was actually transferred + + align:start position:0% +organisms but was actually transferred + + + align:start position:0% +organisms but was actually transferred +into it from another + + align:start position:0% +into it from another + + + align:start position:0% +into it from another +source and I don't have time to go + + align:start position:0% +source and I don't have time to go + + + align:start position:0% +source and I don't have time to go +actually into the mechanisms um if + + align:start position:0% +actually into the mechanisms um if + + + align:start position:0% +actually into the mechanisms um if +you're interested I teach a a graduate + + align:start position:0% +you're interested I teach a a graduate + + + align:start position:0% +you're interested I teach a a graduate +class um that a lot of undergraduates + + align:start position:0% +class um that a lot of undergraduates + + + align:start position:0% +class um that a lot of undergraduates +actually take in our department + + align:start position:0% +actually take in our department + + + align:start position:0% +actually take in our department +environmental microbiology where we + + align:start position:0% +environmental microbiology where we + + + align:start position:0% +environmental microbiology where we +discuss a lot of the mechanisms it's + + align:start position:0% +discuss a lot of the mechanisms it's + + + align:start position:0% +discuss a lot of the mechanisms it's +basically a lot of viruses can affect + + align:start position:0% +basically a lot of viruses can affect + + + align:start position:0% +basically a lot of viruses can affect +Gene transfer um but also plasmas and + + align:start position:0% + + + + align:start position:0% + +transposons but for bacteria again you + + align:start position:0% +transposons but for bacteria again you + + + align:start position:0% +transposons but for bacteria again you +should remember that new function is + + align:start position:0% +should remember that new function is + + + align:start position:0% +should remember that new function is +actually often times often times arises + + align:start position:0% +actually often times often times arises + + + align:start position:0% +actually often times often times arises +by lateral Gene transfer and one of the + + align:start position:0% +by lateral Gene transfer and one of the + + + align:start position:0% +by lateral Gene transfer and one of the +interesting things is that Lal Gene + + align:start position:0% +interesting things is that Lal Gene + + + align:start position:0% +interesting things is that Lal Gene +transfer is actually very important in + + align:start position:0% +transfer is actually very important in + + + align:start position:0% +transfer is actually very important in +um the evolution of pathogenic + + align:start position:0% + + + + align:start position:0% + +bacteria so the so-called + + align:start position:0% + + + + align:start position:0% + +virulence genes which are the genes that + + align:start position:0% +virulence genes which are the genes that + + + align:start position:0% +virulence genes which are the genes that +basically um affect + + align:start position:0% +basically um affect + + + align:start position:0% +basically um affect +pathogenesis a question + + align:start position:0% + + + + align:start position:0% + +among pathogenic + + align:start position:0% + + + + align:start position:0% + +bacteria often + + align:start position:0% + + + + align:start position:0% + +arise bilateral CH + + align:start position:0% + + + + align:start position:0% + +transfer okay + + align:start position:0% +transfer okay + + + align:start position:0% +transfer okay +any + + align:start position:0% + + + + align:start position:0% + +questions okay now for + + align:start position:0% +questions okay now for + + + align:start position:0% +questions okay now for +ukaria I just want to make the + + align:start position:0% + + + + align:start position:0% + +point that their genomes are generally + + align:start position:0% +point that their genomes are generally + + + align:start position:0% +point that their genomes are generally +orders of magnitudes larger + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +okay and that the exons so the things + + align:start position:0% +okay and that the exons so the things + + + align:start position:0% +okay and that the exons so the things +the stretches that really encode the + + align:start position:0% +the stretches that really encode the + + + align:start position:0% +the stretches that really encode the +protein uh that makes up uh the organism + + align:start position:0% +protein uh that makes up uh the organism + + + align:start position:0% +protein uh that makes up uh the organism +the Exon are typically only + + align:start position:0% +the Exon are typically only + + + align:start position:0% +the Exon are typically only +few + + align:start position:0% +few + + + align:start position:0% +few +perc of the + + align:start position:0% + + + + align:start position:0% + +genome that's particularly in higher + + align:start position:0% +genome that's particularly in higher + + + align:start position:0% +genome that's particularly in higher +ukar yeasts for example have a much more + + align:start position:0% +ukar yeasts for example have a much more + + + align:start position:0% +ukar yeasts for example have a much more +compact genome also but um we for + + align:start position:0% +compact genome also but um we for + + + align:start position:0% +compact genome also but um we for +example are full of DNA that people + + align:start position:0% +example are full of DNA that people + + + align:start position:0% +example are full of DNA that people +still have a very hard time figuring out + + align:start position:0% +still have a very hard time figuring out + + + align:start position:0% +still have a very hard time figuring out +what it actually does but it seems that + + align:start position:0% +what it actually does but it seems that + + + align:start position:0% +what it actually does but it seems that +the majority of the genome + + align:start position:0% + + + + align:start position:0% + +soal repeated + + align:start position:0% + + + + align:start position:0% + +sequences many of which seem to be + + align:start position:0% +sequences many of which seem to be + + + align:start position:0% +sequences many of which seem to be +ancient retroviruses that have inserted + + align:start position:0% +ancient retroviruses that have inserted + + + align:start position:0% +ancient retroviruses that have inserted +themselves into the genome and have + + align:start position:0% +themselves into the genome and have + + + align:start position:0% +themselves into the genome and have +since then lost actually their + + align:start position:0% + + + + align:start position:0% + +function okay so in the remaining time I + + align:start position:0% +function okay so in the remaining time I + + + align:start position:0% +function okay so in the remaining time I +want to just give you an example of um + + align:start position:0% +want to just give you an example of um + + + align:start position:0% +want to just give you an example of um +how we now can use these techniques that + + align:start position:0% +how we now can use these techniques that + + + align:start position:0% +how we now can use these techniques that +are outlined + + align:start position:0% +are outlined + + + align:start position:0% +are outlined +before to learn something + + align:start position:0% +before to learn something + + + align:start position:0% +before to learn something +about microorganisms in the + + align:start position:0% + + + + align:start position:0% + +environment called Environmental + + align:start position:0% + + + + align:start position:0% + +basically um the way this all was + + align:start position:0% +basically um the way this all was + + + align:start position:0% +basically um the way this all was +started was by going into the + + align:start position:0% +started was by going into the + + + align:start position:0% +started was by going into the +environment and extracting nucleic acids + + align:start position:0% +environment and extracting nucleic acids + + + align:start position:0% +environment and extracting nucleic acids +and treating them exactly the same way + + align:start position:0% +and treating them exactly the same way + + + align:start position:0% +and treating them exactly the same way +as if you had a single genome but again + + align:start position:0% +as if you had a single genome but again + + + align:start position:0% +as if you had a single genome but again +remember we have a very large mixture of + + align:start position:0% +remember we have a very large mixture of + + + align:start position:0% +remember we have a very large mixture of +microorganisms present in the + + align:start position:0% +microorganisms present in the + + + align:start position:0% +microorganisms present in the +environment and where this was mostly + + align:start position:0% +environment and where this was mostly + + + align:start position:0% +environment and where this was mostly +done was in the ocean actually and what + + align:start position:0% +done was in the ocean actually and what + + + align:start position:0% +done was in the ocean actually and what +people did was constructed those back + + align:start position:0% +people did was constructed those back + + + align:start position:0% +people did was constructed those back +clones directly from the environment and + + align:start position:0% +clones directly from the environment and + + + align:start position:0% +clones directly from the environment and +then looked amongst those back clones + + align:start position:0% +then looked amongst those back clones + + + align:start position:0% +then looked amongst those back clones +for specific 16s ribosomal RNA genes + + align:start position:0% +for specific 16s ribosomal RNA genes + + + align:start position:0% +for specific 16s ribosomal RNA genes +remember this is the marker that we have + + align:start position:0% +remember this is the marker that we have + + + align:start position:0% +remember this is the marker that we have +for microorganisms in the environment we + + align:start position:0% +for microorganisms in the environment we + + + align:start position:0% +for microorganisms in the environment we +know the diversity of microorganisms + + align:start position:0% +know the diversity of microorganisms + + + align:start position:0% +know the diversity of microorganisms +through those types of genes and we have + + align:start position:0% +through those types of genes and we have + + + align:start position:0% +through those types of genes and we have +a lot of data available and so in order + + align:start position:0% +a lot of data available and so in order + + + align:start position:0% +a lot of data available and so in order +to link a specific function that such an + + align:start position:0% +to link a specific function that such an + + + align:start position:0% +to link a specific function that such an +organism that we only know from the 16 a + + align:start position:0% +organism that we only know from the 16 a + + + align:start position:0% +organism that we only know from the 16 a +ribosomal RNA genes um so to ask the + + align:start position:0% +ribosomal RNA genes um so to ask the + + + align:start position:0% +ribosomal RNA genes um so to ask the +question what sort of function this + + align:start position:0% +question what sort of function this + + + align:start position:0% +question what sort of function this +organism might be carrying out in the + + align:start position:0% +organism might be carrying out in the + + + align:start position:0% +organism might be carrying out in the +environment it's very useful to sequence + + align:start position:0% +environment it's very useful to sequence + + + align:start position:0% +environment it's very useful to sequence +back clones that have 6 s ribosomal RNA + + align:start position:0% +back clones that have 6 s ribosomal RNA + + + align:start position:0% +back clones that have 6 s ribosomal RNA +genes on them and then determine what + + align:start position:0% +genes on them and then determine what + + + align:start position:0% +genes on them and then determine what +kinds of protein coding genes are on + + align:start position:0% +kinds of protein coding genes are on + + + align:start position:0% +kinds of protein coding genes are on +there that might reveal some of the + + align:start position:0% +there that might reveal some of the + + + align:start position:0% +there that might reveal some of the +function of the organism in the + + align:start position:0% +function of the organism in the + + + align:start position:0% +function of the organism in the +environment and one example that I want + + align:start position:0% +environment and one example that I want + + + align:start position:0% +environment and one example that I want +to show you is that um of the proteo + + align:start position:0% +to show you is that um of the proteo + + + align:start position:0% +to show you is that um of the proteo +[Applause] + + align:start position:0% + + + + align:start position:0% + +ropin so basically the + + align:start position:0% + + + + align:start position:0% + +initial um task was to sequence back + + align:start position:0% +initial um task was to sequence back + + + align:start position:0% +initial um task was to sequence back +clones + + align:start position:0% + + + + align:start position:0% + +containing ribosomal RNA + + align:start position:0% + + + + align:start position:0% + +genes and look for other + + align:start position:0% + + + + align:start position:0% + +genes that might reveal some of the + + align:start position:0% + + + + align:start position:0% + +function so you don't want to look for + + align:start position:0% +function so you don't want to look for + + + align:start position:0% +function so you don't want to look for +all the genes that encode proteins that + + align:start position:0% +all the genes that encode proteins that + + + align:start position:0% +all the genes that encode proteins that +are important in the cell cycle or + + align:start position:0% +are important in the cell cycle or + + + align:start position:0% +are important in the cell cycle or +things like that but really sort of + + align:start position:0% +things like that but really sort of + + + align:start position:0% +things like that but really sort of +metabolic genes that might tell you + + align:start position:0% +metabolic genes that might tell you + + + align:start position:0% +metabolic genes that might tell you +something about the um type of + + align:start position:0% +something about the um type of + + + align:start position:0% +something about the um type of +metabolism that this organism carries + + align:start position:0% +metabolism that this organism carries + + + align:start position:0% +metabolism that this organism carries +out in the + + align:start position:0% +out in the + + + align:start position:0% +out in the +environment and so what the first + + align:start position:0% +environment and so what the first + + + align:start position:0% +environment and so what the first +example that turned out to be really + + align:start position:0% +example that turned out to be really + + + align:start position:0% +example that turned out to be really +really important was that people found + + align:start position:0% +really important was that people found + + + align:start position:0% +really important was that people found +uh ropin genes on one of those um back + + align:start position:0% +uh ropin genes on one of those um back + + + align:start position:0% +uh ropin genes on one of those um back +fragments and it turns out this ropin + + align:start position:0% +fragments and it turns out this ropin + + + align:start position:0% +fragments and it turns out this ropin +catalyzes or these ropson genes produce + + align:start position:0% +catalyzes or these ropson genes produce + + + align:start position:0% +catalyzes or these ropson genes produce +a protein that inserts itself into the + + align:start position:0% +a protein that inserts itself into the + + + align:start position:0% +a protein that inserts itself into the +bacterial + + align:start position:0% +bacterial + + + align:start position:0% +bacterial +membrane and is a photo receptor the so + + align:start position:0% +membrane and is a photo receptor the so + + + align:start position:0% +membrane and is a photo receptor the so +when it's hit by light it actually + + align:start position:0% +when it's hit by light it actually + + + align:start position:0% +when it's hit by light it actually +affects uh it's an it becomes a proton + + align:start position:0% +affects uh it's an it becomes a proton + + + align:start position:0% +affects uh it's an it becomes a proton +pump so it expels protons from the cell + + align:start position:0% +pump so it expels protons from the cell + + + align:start position:0% +pump so it expels protons from the cell +interior to the outside and you already + + align:start position:0% +interior to the outside and you already + + + align:start position:0% +interior to the outside and you already +know that this is important in energy + + align:start position:0% +know that this is important in energy + + + align:start position:0% +know that this is important in energy +generation in all living cells so proton + + align:start position:0% +generation in all living cells so proton + + + align:start position:0% +generation in all living cells so proton +gradients across membranes basically + + align:start position:0% +gradients across membranes basically + + + align:start position:0% +gradients across membranes basically +give the cells sort of a battery status + + align:start position:0% +give the cells sort of a battery status + + + align:start position:0% +give the cells sort of a battery status +that can be exploited by atpa molecules + + align:start position:0% +that can be exploited by atpa molecules + + + align:start position:0% +that can be exploited by atpa molecules +or atpa proteins that equalize the + + align:start position:0% +or atpa proteins that equalize the + + + align:start position:0% +or atpa proteins that equalize the +proton gradient and affect ATP synthesis + + align:start position:0% +proton gradient and affect ATP synthesis + + + align:start position:0% +proton gradient and affect ATP synthesis +in doing + + align:start position:0% +in doing + + + align:start position:0% +in doing +so now why is this so important well it + + align:start position:0% +so now why is this so important well it + + + align:start position:0% +so now why is this so important well it +turned out that this type of protein is + + align:start position:0% +turned out that this type of protein is + + + align:start position:0% +turned out that this type of protein is +present in almost all microbial cells + + align:start position:0% +present in almost all microbial cells + + + align:start position:0% +present in almost all microbial cells +that were previously thought to be + + align:start position:0% +that were previously thought to be + + + align:start position:0% +that were previously thought to be +heterotrophs alone in the ocean in the + + align:start position:0% +heterotrophs alone in the ocean in the + + + align:start position:0% +heterotrophs alone in the ocean in the +in the parts of the ocean that uh + + align:start position:0% +in the parts of the ocean that uh + + + align:start position:0% +in the parts of the ocean that uh +receive enough light and what this means + + align:start position:0% +receive enough light and what this means + + + align:start position:0% +receive enough light and what this means +is that our estimates of the global + + align:start position:0% +is that our estimates of the global + + + align:start position:0% +is that our estimates of the global +carbon budget of the ocean were + + align:start position:0% +carbon budget of the ocean were + + + align:start position:0% +carbon budget of the ocean were +basically wrong okay because most + + align:start position:0% +basically wrong okay because most + + + align:start position:0% +basically wrong okay because most +microorganisms in the ocean have + + align:start position:0% + + + + align:start position:0% + +this so most + + align:start position:0% + + + + align:start position:0% + +procaryotes in the + + align:start position:0% + + + + align:start position:0% + +ocean have a light + + align:start position:0% +ocean have a light + + + align:start position:0% +ocean have a light +driven proton + + align:start position:0% + + + + align:start position:0% + +pump which is called + + align:start position:0% + + + + align:start position:0% + +proteo + + align:start position:0% + + + + align:start position:0% + +ropin and it basically allows them + + align:start position:0% +ropin and it basically allows them + + + align:start position:0% +ropin and it basically allows them +um to gain + + align:start position:0% + + + + align:start position:0% + +energy from sunlight + + align:start position:0% + + + + align:start position:0% + +and there's an increasing number of such + + align:start position:0% +and there's an increasing number of such + + + align:start position:0% +and there's an increasing number of such +examples now where we we're really + + align:start position:0% +examples now where we we're really + + + align:start position:0% +examples now where we we're really +learning to interpret um environmental + + align:start position:0% +learning to interpret um environmental + + + align:start position:0% +learning to interpret um environmental +uh communities and Environ the function + + align:start position:0% +uh communities and Environ the function + + + align:start position:0% +uh communities and Environ the function +of environmental microbial communities + + align:start position:0% +of environmental microbial communities + + + align:start position:0% +of environmental microbial communities +through those genomic approaches and it + + align:start position:0% +through those genomic approaches and it + + + align:start position:0% +through those genomic approaches and it +reveals um + + align:start position:0% +reveals um + + + align:start position:0% +reveals um +basically + + align:start position:0% +basically + + + align:start position:0% +basically +uh an enormous diversity of organisms + + align:start position:0% +uh an enormous diversity of organisms + + + align:start position:0% +uh an enormous diversity of organisms +out there what we're also learning to do + + align:start position:0% +out there what we're also learning to do + + + align:start position:0% +out there what we're also learning to do +now is to assemble entire genomes from + + align:start position:0% +now is to assemble entire genomes from + + + align:start position:0% +now is to assemble entire genomes from +those samples by applying um genomic + + align:start position:0% +those samples by applying um genomic + + + align:start position:0% +those samples by applying um genomic +techniques and this is an example here + + align:start position:0% +techniques and this is an example here + + + align:start position:0% +techniques and this is an example here +where you see uh this was published last + + align:start position:0% +where you see uh this was published last + + + align:start position:0% +where you see uh this was published last +year where people went out and basically + + align:start position:0% +year where people went out and basically + + + align:start position:0% +year where people went out and basically +were able to piece together from pieces + + align:start position:0% +were able to piece together from pieces + + + align:start position:0% +were able to piece together from pieces +of genes obtained from the environment + + align:start position:0% +of genes obtained from the environment + + + align:start position:0% +of genes obtained from the environment +entire genomes or fragments of entire + + align:start position:0% +entire genomes or fragments of entire + + + align:start position:0% +entire genomes or fragments of entire +genomes and that's shown here um those + + align:start position:0% +genomes and that's shown here um those + + + align:start position:0% +genomes and that's shown here um those +contigous + + align:start position:0% +contigous + + + align:start position:0% +contigous +sequences okay so and if you have any + + align:start position:0% +sequences okay so and if you have any + + + align:start position:0% +sequences okay so and if you have any +questions let me know via email or um if + + align:start position:0% +questions let me know via email or um if + + + align:start position:0% +questions let me know via email or um if +you're interested in pursuing this + + align:start position:0% +you're interested in pursuing this + + + align:start position:0% +you're interested in pursuing this +further uh I also teach another class in + + align:start position:0% +further uh I also teach another class in + + + align:start position:0% +further uh I also teach another class in +civil environmental engineering \ No newline at end of file diff --git a/OYcdw5vOgIc.txt b/OYcdw5vOgIc.txt new file mode 100644 index 0000000000000000000000000000000000000000..2650172b6bad120810b42b0f2f86152adef5a93a --- /dev/null +++ b/OYcdw5vOgIc.txt @@ -0,0 +1,13939 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT open courseware continue + + align:start position:0% +will help MIT open courseware continue + + + align:start position:0% +will help MIT open courseware continue +to offer highquality educational + + align:start position:0% +to offer highquality educational + + + align:start position:0% +to offer highquality educational +resources for free to make a donation or + + align:start position:0% +resources for free to make a donation or + + + align:start position:0% +resources for free to make a donation or +to view additional materials from + + align:start position:0% +to view additional materials from + + + align:start position:0% +to view additional materials from +hundreds of MIT courses visit MIT + + align:start position:0% +hundreds of MIT courses visit MIT + + + align:start position:0% +hundreds of MIT courses visit MIT +opencare at ocw.mit.edu + + align:start position:0% + + + + align:start position:0% + +all right + + align:start position:0% +all right + + + align:start position:0% +all right +so let's continue uh talking about + + align:start position:0% +so let's continue uh talking about + + + align:start position:0% +so let's continue uh talking about +maximum likelihood estimation in the + + align:start position:0% +maximum likelihood estimation in the + + + align:start position:0% +maximum likelihood estimation in the +context of generalized linear Models All + + align:start position:0% +context of generalized linear Models All + + + align:start position:0% +context of generalized linear Models All +right so in those generalized linear + + align:start position:0% +right so in those generalized linear + + + align:start position:0% +right so in those generalized linear +models what we spend uh most of the past + + align:start position:0% +models what we spend uh most of the past + + + align:start position:0% +models what we spend uh most of the past +lectures uh working on is the + + align:start position:0% +lectures uh working on is the + + + align:start position:0% +lectures uh working on is the +conditional + + align:start position:0% +conditional + + + align:start position:0% +conditional +distribution of Y sorry of Y given + + align:start position:0% +distribution of Y sorry of Y given + + + align:start position:0% +distribution of Y sorry of Y given +X and we're going to assume that this uh + + align:start position:0% +X and we're going to assume that this uh + + + align:start position:0% +X and we're going to assume that this uh +follow some + + align:start position:0% +follow some + + + align:start position:0% +follow some +uh + + align:start position:0% + + + + align:start position:0% + +distribution in the exponential + + align:start position:0% + + + + align:start position:0% + +family okay and so what it means is that + + align:start position:0% +family okay and so what it means is that + + + align:start position:0% +family okay and so what it means is that +if I look at the uh the density say or + + align:start position:0% +if I look at the uh the density say or + + + align:start position:0% +if I look at the uh the density say or +the pmf but uh let's talk about + + align:start position:0% +the pmf but uh let's talk about + + + align:start position:0% +the pmf but uh let's talk about +densities to make things clear we're + + align:start position:0% +densities to make things clear we're + + + align:start position:0% +densities to make things clear we're +going to assume that uh y given f x as + + align:start position:0% +going to assume that uh y given f x as + + + align:start position:0% +going to assume that uh y given f x as +distribution so X is now fixed because + + align:start position:0% +distribution so X is now fixed because + + + align:start position:0% +distribution so X is now fixed because +we're conditioning on it and it has a + + align:start position:0% +we're conditioning on it and it has a + + + align:start position:0% +we're conditioning on it and it has a +density which is of this + + align:start position:0% + + + + align:start position:0% + +form C of y + + align:start position:0% +form C of y + + + align:start position:0% +form C of y +i okay so the C again we don't really + + align:start position:0% +i okay so the C again we don't really + + + align:start position:0% +i okay so the C again we don't really +need to think about it this is something + + align:start position:0% +need to think about it this is something + + + align:start position:0% +need to think about it this is something +that's going to come out naturally as + + align:start position:0% +that's going to come out naturally as + + + align:start position:0% +that's going to come out naturally as +soon as you need a normalization factor + + align:start position:0% +soon as you need a normalization factor + + + align:start position:0% +soon as you need a normalization factor +and so here what it means so if this is + + align:start position:0% +and so here what it means so if this is + + + align:start position:0% +and so here what it means so if this is +the distribution of Y given x i so + + align:start position:0% +the distribution of Y given x i so + + + align:start position:0% +the distribution of Y given x i so +that's the density of + + align:start position:0% +that's the density of + + + align:start position:0% +that's the density of +y i given x i is equal to Little X I so + + align:start position:0% +y i given x i is equal to Little X I so + + + align:start position:0% +y i given x i is equal to Little X I so +if it's the conditional distribution of + + align:start position:0% +if it's the conditional distribution of + + + align:start position:0% +if it's the conditional distribution of +Yi given x i it should depend on XI + + align:start position:0% +Yi given x i it should depend on XI + + + align:start position:0% +Yi given x i it should depend on XI +somehow and it does not appear to depend + + align:start position:0% +somehow and it does not appear to depend + + + align:start position:0% +somehow and it does not appear to depend +on XI and here the model is going to be + + align:start position:0% +on XI and here the model is going to be + + + align:start position:0% +on XI and here the model is going to be +on Theta I which is just a function + + align:start position:0% +on Theta I which is just a function + + + align:start position:0% +on Theta I which is just a function +Theta I of x i and we're going to make a + + align:start position:0% +Theta I of x i and we're going to make a + + + align:start position:0% +Theta I of x i and we're going to make a +very specific one it's going to be a + + align:start position:0% +very specific one it's going to be a + + + align:start position:0% +very specific one it's going to be a +function of a linear uh uh uh a linear + + align:start position:0% +function of a linear uh uh uh a linear + + + align:start position:0% +function of a linear uh uh uh a linear +uh um form of the XI so really we're + + align:start position:0% +uh um form of the XI so really we're + + + align:start position:0% +uh um form of the XI so really we're +going to take something which is of the + + align:start position:0% +going to take something which is of the + + + align:start position:0% +going to take something which is of the +form Theta I which is really just this + + align:start position:0% +form Theta I which is really just this + + + align:start position:0% +form Theta I which is really just this +Theta does not depend on XI of XI + + align:start position:0% +Theta does not depend on XI of XI + + + align:start position:0% +Theta does not depend on XI of XI +transpose some beta okay so all these + + align:start position:0% +transpose some beta okay so all these + + + align:start position:0% +transpose some beta okay so all these +parts here this is really some modeling + + align:start position:0% +parts here this is really some modeling + + + align:start position:0% +parts here this is really some modeling +assumptions that we're + + align:start position:0% +assumptions that we're + + + align:start position:0% +assumptions that we're +making once we've agreed on what + + align:start position:0% +making once we've agreed on what + + + align:start position:0% +making once we've agreed on what +distribution we want okay so to do that + + align:start position:0% +distribution we want okay so to do that + + + align:start position:0% +distribution we want okay so to do that +so our goal of course is going to try to + + align:start position:0% +so our goal of course is going to try to + + + align:start position:0% +so our goal of course is going to try to +understand understand what this beta is + + align:start position:0% +understand understand what this beta is + + + align:start position:0% +understand understand what this beta is +there's one beta here what's important + + align:start position:0% +there's one beta here what's important + + + align:start position:0% +there's one beta here what's important +is that this beta does + + align:start position:0% + + + + align:start position:0% + +not + + align:start position:0% +not + + + align:start position:0% +not +depend on I so if I observe pairs x i y + + align:start position:0% +depend on I so if I observe pairs x i y + + + align:start position:0% +depend on I so if I observe pairs x i y +i let's say I observe n of them IAL 1 to + + align:start position:0% +i let's say I observe n of them IAL 1 to + + + align:start position:0% +i let's say I observe n of them IAL 1 to +n The Hope is that as I accumulate more + + align:start position:0% +n The Hope is that as I accumulate more + + + align:start position:0% +n The Hope is that as I accumulate more +and more pairs of this form where + + align:start position:0% +and more pairs of this form where + + + align:start position:0% +and more pairs of this form where +there's always the same parameter that + + align:start position:0% +there's always the same parameter that + + + align:start position:0% +there's always the same parameter that +links XI to Yi that's this parameter + + align:start position:0% +links XI to Yi that's this parameter + + + align:start position:0% +links XI to Yi that's this parameter +beta then I should have a better and + + align:start position:0% +beta then I should have a better and + + + align:start position:0% +beta then I should have a better and +better estimation of this beta because + + align:start position:0% +better estimation of this beta because + + + align:start position:0% +better estimation of this beta because +it's always the same and that's + + align:start position:0% +it's always the same and that's + + + align:start position:0% +it's always the same and that's +essentially what couples all of our + + align:start position:0% +essentially what couples all of our + + + align:start position:0% +essentially what couples all of our +distribution if I did not assume this + + align:start position:0% +distribution if I did not assume this + + + align:start position:0% +distribution if I did not assume this +then I could have a different + + align:start position:0% +then I could have a different + + + align:start position:0% +then I could have a different +distribution for each pair XI given Yi + + align:start position:0% +distribution for each pair XI given Yi + + + align:start position:0% +distribution for each pair XI given Yi +and I would not be able to do any + + align:start position:0% +and I would not be able to do any + + + align:start position:0% +and I would not be able to do any +statistics there would nothing nothing + + align:start position:0% +statistics there would nothing nothing + + + align:start position:0% +statistics there would nothing nothing +would average in the end but here I have + + align:start position:0% +would average in the end but here I have + + + align:start position:0% +would average in the end but here I have +the same beta which means that I can + + align:start position:0% +the same beta which means that I can + + + align:start position:0% +the same beta which means that I can +hope to do statistics and average errors + + align:start position:0% +hope to do statistics and average errors + + + align:start position:0% +hope to do statistics and average errors +Z okay so I'm going to collect so uh + + align:start position:0% +Z okay so I'm going to collect so uh + + + align:start position:0% +Z okay so I'm going to collect so uh +I'll back to this so but as usual in the + + align:start position:0% +I'll back to this so but as usual in the + + + align:start position:0% +I'll back to this so but as usual in the +linear regression model we're going to + + align:start position:0% +linear regression model we're going to + + + align:start position:0% +linear regression model we're going to +collect all our observations Yi so here + + align:start position:0% +collect all our observations Yi so here + + + align:start position:0% +collect all our observations Yi so here +I'm going to assume that they're real + + align:start position:0% +I'm going to assume that they're real + + + align:start position:0% +I'm going to assume that they're real +valued and that my X eyes are val takes + + align:start position:0% +valued and that my X eyes are val takes + + + align:start position:0% +valued and that my X eyes are val takes +value in RP just like in the regression + + align:start position:0% +value in RP just like in the regression + + + align:start position:0% +value in RP just like in the regression +model and I'm going to collect all my y + + align:start position:0% +model and I'm going to collect all my y + + + align:start position:0% +model and I'm going to collect all my y +eyes into one big Vector Y in RN and all + + align:start position:0% +eyes into one big Vector Y in RN and all + + + align:start position:0% +eyes into one big Vector Y in RN and all +my x's into one big Matrix in RN * + + align:start position:0% +my x's into one big Matrix in RN * + + + align:start position:0% +my x's into one big Matrix in RN * +P okay just like for the linear + + align:start position:0% +P okay just like for the linear + + + align:start position:0% +P okay just like for the linear +aggression + + align:start position:0% +aggression + + + align:start position:0% +aggression +model all right + + align:start position:0% +model all right + + + align:start position:0% +model all right +so again what I'm interested in here + + align:start position:0% +so again what I'm interested in here + + + align:start position:0% +so again what I'm interested in here +here is the conditional + + align:start position:0% +here is the conditional + + + align:start position:0% +here is the conditional +distribution of Yi given XI okay and I + + align:start position:0% +distribution of Yi given XI okay and I + + + align:start position:0% +distribution of Yi given XI okay and I +said this is this distribution when + + align:start position:0% +said this is this distribution when + + + align:start position:0% +said this is this distribution when +we're talking about regression I defined + + align:start position:0% +we're talking about regression I defined + + + align:start position:0% +we're talking about regression I defined +last time what the definition of a + + align:start position:0% +last time what the definition of a + + + align:start position:0% +last time what the definition of a +regression function was it's just one + + align:start position:0% +regression function was it's just one + + + align:start position:0% +regression function was it's just one +particular aspect of this conditional + + align:start position:0% +particular aspect of this conditional + + + align:start position:0% +particular aspect of this conditional +distribution is the conditional + + align:start position:0% +distribution is the conditional + + + align:start position:0% +distribution is the conditional +expectation of y i given + + align:start position:0% +expectation of y i given + + + align:start position:0% +expectation of y i given +XI okay and so this conditional + + align:start position:0% +XI okay and so this conditional + + + align:start position:0% +XI okay and so this conditional +expectation I will denote it + + align:start position:0% +expectation I will denote it + + + align:start position:0% +expectation I will denote it +by so if I talk about the conditional + + align:start position:0% + + + + align:start position:0% + +so that's I'm going to call it say muui + + align:start position:0% +so that's I'm going to call it say muui + + + align:start position:0% +so that's I'm going to call it say muui +which is the conditional expectation of + + align:start position:0% +which is the conditional expectation of + + + align:start position:0% +which is the conditional expectation of +Yi given x i equals some little X I + + align:start position:0% +Yi given x i equals some little X I + + + align:start position:0% +Yi given x i equals some little X I +say you can forget about this part if + + align:start position:0% +say you can forget about this part if + + + align:start position:0% +say you can forget about this part if +you find it confusing it really doesn't + + align:start position:0% +you find it confusing it really doesn't + + + align:start position:0% +you find it confusing it really doesn't +matter it's just so that this is just + + align:start position:0% +matter it's just so that this is just + + + align:start position:0% +matter it's just so that this is just +this means that this is a function of + + align:start position:0% +this means that this is a function of + + + align:start position:0% +this means that this is a function of +little XI but if I only had expectation + + align:start position:0% +little XI but if I only had expectation + + + align:start position:0% +little XI but if I only had expectation +of Yi given big XI this would be just a + + align:start position:0% +of Yi given big XI this would be just a + + + align:start position:0% +of Yi given big XI this would be just a +function of big XI right so it really + + align:start position:0% +function of big XI right so it really + + + align:start position:0% +function of big XI right so it really +doesn't change anything it's just a + + align:start position:0% +doesn't change anything it's just a + + + align:start position:0% +doesn't change anything it's just a +matter of + + align:start position:0% +matter of + + + align:start position:0% +matter of +notation okay so just uh forget about + + align:start position:0% +notation okay so just uh forget about + + + align:start position:0% +notation okay so just uh forget about +this part but uh I'll just uh do it like + + align:start position:0% +this part but uh I'll just uh do it like + + + align:start position:0% +this part but uh I'll just uh do it like +that here okay so this is just the + + align:start position:0% +that here okay so this is just the + + + align:start position:0% +that here okay so this is just the +conditional expectation of y i given XI + + align:start position:0% +conditional expectation of y i given XI + + + align:start position:0% +conditional expectation of y i given XI +all right it just depends on XI so I + + align:start position:0% +all right it just depends on XI so I + + + align:start position:0% +all right it just depends on XI so I +particularly depends on I and so I will + + align:start position:0% +particularly depends on I and so I will + + + align:start position:0% +particularly depends on I and so I will +call it mui but I know that since I'm in + + align:start position:0% +call it mui but I know that since I'm in + + + align:start position:0% +call it mui but I know that since I'm in +a canonical exponential + + align:start position:0% +a canonical exponential + + + align:start position:0% +a canonical exponential +family then I know that mui is actually + + align:start position:0% +family then I know that mui is actually + + + align:start position:0% +family then I know that mui is actually +B Prime of theta I + + align:start position:0% +B Prime of theta I + + + align:start position:0% +B Prime of theta I +okay so there's a onetoone link between + + align:start position:0% +okay so there's a onetoone link between + + + align:start position:0% +okay so there's a onetoone link between +the canonical parameter of my + + align:start position:0% +the canonical parameter of my + + + align:start position:0% +the canonical parameter of my +exponential family and the mean mui the + + align:start position:0% +exponential family and the mean mui the + + + align:start position:0% +exponential family and the mean mui the +conditional + + align:start position:0% +conditional + + + align:start position:0% +conditional +expectation and the modeling assumption + + align:start position:0% +expectation and the modeling assumption + + + align:start position:0% +expectation and the modeling assumption +we're going to make is not directly + + align:start position:0% +we're going to make is not directly + + + align:start position:0% +we're going to make is not directly +that's we remember that was the second + + align:start position:0% +that's we remember that was the second + + + align:start position:0% +that's we remember that was the second +aspect of the generalized linear model + + align:start position:0% +aspect of the generalized linear model + + + align:start position:0% +aspect of the generalized linear model +we're not going to assume that Theta I + + align:start position:0% +we're not going to assume that Theta I + + + align:start position:0% +we're not going to assume that Theta I +itself directly depends on XI we're + + align:start position:0% +itself directly depends on XI we're + + + align:start position:0% +itself directly depends on XI we're +going to assume that mui has a + + align:start position:0% +going to assume that mui has a + + + align:start position:0% +going to assume that mui has a +particular dependence on XI through the + + align:start position:0% +particular dependence on XI through the + + + align:start position:0% +particular dependence on XI through the +link function right so again we're back + + align:start position:0% +link function right so again we're back + + + align:start position:0% +link function right so again we're back +to + + align:start position:0% +to + + + align:start position:0% +to +modeling so we have a link function + + align:start position:0% + + + + align:start position:0% + +G and we + + align:start position:0% + + + + align:start position:0% + +assume that + + align:start position:0% +assume that + + + align:start position:0% +assume that +mui + + align:start position:0% +mui + + + align:start position:0% +mui +depends on + + align:start position:0% +depends on + + + align:start position:0% +depends on +XI as + + align:start position:0% + + + + align:start position:0% + +follows G of mui and remember G all G + + align:start position:0% +follows G of mui and remember G all G + + + align:start position:0% +follows G of mui and remember G all G +does for us is really map the space in + + align:start position:0% +does for us is really map the space in + + + align:start position:0% +does for us is really map the space in +which mui lives which could be just the + + align:start position:0% +which mui lives which could be just the + + + align:start position:0% +which mui lives which could be just the +interval 01 to the entire real line all + + align:start position:0% +interval 01 to the entire real line all + + + align:start position:0% +interval 01 to the entire real line all +right and we're going to assume that + + align:start position:0% +right and we're going to assume that + + + align:start position:0% +right and we're going to assume that +this thing that lives in the real line + + align:start position:0% +this thing that lives in the real line + + + align:start position:0% +this thing that lives in the real line +is just X I transpose beta I should + + align:start position:0% +is just X I transpose beta I should + + + align:start position:0% +is just X I transpose beta I should +maybe put a small One X I transpose beta + + align:start position:0% +maybe put a small One X I transpose beta + + + align:start position:0% +maybe put a small One X I transpose beta +okay so we're making indeed some + + align:start position:0% +okay so we're making indeed some + + + align:start position:0% +okay so we're making indeed some +modeling assumption but compared to uh + + align:start position:0% +modeling assumption but compared to uh + + + align:start position:0% +modeling assumption but compared to uh +in the linear regression model we only + + align:start position:0% +in the linear regression model we only + + + align:start position:0% +in the linear regression model we only +assume that mui was XI transpose beta so + + align:start position:0% +assume that mui was XI transpose beta so + + + align:start position:0% +assume that mui was XI transpose beta so +if you want to make a parallel between + + align:start position:0% +if you want to make a parallel between + + + align:start position:0% +if you want to make a parallel between +generalized linear models and linear + + align:start position:0% +generalized linear models and linear + + + align:start position:0% +generalized linear models and linear +model is just the the only difference is + + align:start position:0% +model is just the the only difference is + + + align:start position:0% +model is just the the only difference is +that g is not the identity necessarily + + align:start position:0% +that g is not the identity necessarily + + + align:start position:0% +that g is not the identity necessarily +in this + + align:start position:0% +in this + + + align:start position:0% +in this +case and all that g does for us is to + + align:start position:0% +case and all that g does for us is to + + + align:start position:0% +case and all that g does for us is to +just make this thing compatible that + + align:start position:0% +just make this thing compatible that + + + align:start position:0% +just make this thing compatible that +those two things on the left and the + + align:start position:0% +those two things on the left and the + + + align:start position:0% +those two things on the left and the +right of this equality live in the same + + align:start position:0% +right of this equality live in the same + + + align:start position:0% +right of this equality live in the same +space so in a way we're not making a + + align:start position:0% +space so in a way we're not making a + + + align:start position:0% +space so in a way we're not making a +much you know bigger leap of faith uh uh + + align:start position:0% +much you know bigger leap of faith uh uh + + + align:start position:0% +much you know bigger leap of faith uh uh +by assuming a linear model the linear + + align:start position:0% +by assuming a linear model the linear + + + align:start position:0% +by assuming a linear model the linear +link is already here we're just making + + align:start position:0% +link is already here we're just making + + + align:start position:0% +link is already here we're just making +things + + align:start position:0% +things + + + align:start position:0% +things +compatible all right and + + align:start position:0% +compatible all right and + + + align:start position:0% +compatible all right and +so uh this is going to be uh what the so + + align:start position:0% +so uh this is going to be uh what the so + + + align:start position:0% +so uh this is going to be uh what the so +it's always the same link function so + + align:start position:0% +it's always the same link function so + + + align:start position:0% +it's always the same link function so +now if I want to uh go back to uh beta + + align:start position:0% +now if I want to uh go back to uh beta + + + align:start position:0% +now if I want to uh go back to uh beta +right because I'm going to want to + + align:start position:0% +right because I'm going to want to + + + align:start position:0% +right because I'm going to want to +express my likelihood right so if I were + + align:start position:0% +express my likelihood right so if I were + + + align:start position:0% +express my likelihood right so if I were +to express my likelihood from this it + + align:start position:0% +to express my likelihood from this it + + + align:start position:0% +to express my likelihood from this it +would just be a function of theta right + + align:start position:0% +would just be a function of theta right + + + align:start position:0% +would just be a function of theta right +and so if I want to maximize my + + align:start position:0% +and so if I want to maximize my + + + align:start position:0% +and so if I want to maximize my +likelihood I don't want to maximize it + + align:start position:0% +likelihood I don't want to maximize it + + + align:start position:0% +likelihood I don't want to maximize it +in Theta I want to maximize it in beta + + align:start position:0% +in Theta I want to maximize it in beta + + + align:start position:0% +in Theta I want to maximize it in beta +so if I can write my density as a + + align:start position:0% +so if I can write my density as a + + + align:start position:0% +so if I can write my density as a +function of beta then I will be able to + + align:start position:0% +function of beta then I will be able to + + + align:start position:0% +function of beta then I will be able to +write my likelihood as a function of + + align:start position:0% +write my likelihood as a function of + + + align:start position:0% +write my likelihood as a function of +beta and then talk about my maximum + + align:start position:0% +beta and then talk about my maximum + + + align:start position:0% +beta and then talk about my maximum +likelihood as the matter and so all I + + align:start position:0% +likelihood as the matter and so all I + + + align:start position:0% +likelihood as the matter and so all I +need to do is to just say okay how do I + + align:start position:0% +need to do is to just say okay how do I + + + align:start position:0% +need to do is to just say okay how do I +replace Theta by what is I know that + + align:start position:0% +replace Theta by what is I know that + + + align:start position:0% +replace Theta by what is I know that +Theta is a function of beta right I + + align:start position:0% +Theta is a function of beta right I + + + align:start position:0% +Theta is a function of beta right I +wrote it + + align:start position:0% +wrote it + + + align:start position:0% +wrote it +here so the question is what what is + + align:start position:0% +here so the question is what what is + + + align:start position:0% +here so the question is what what is +this function and I actually have access + + align:start position:0% +this function and I actually have access + + + align:start position:0% +this function and I actually have access +to all of this so what I know is that + + align:start position:0% +to all of this so what I know is that + + + align:start position:0% +to all of this so what I know is that +Theta right so mu is B Prime of theta + + align:start position:0% +Theta right so mu is B Prime of theta + + + align:start position:0% +Theta right so mu is B Prime of theta +which means that Theta I is B Prime + + align:start position:0% +which means that Theta I is B Prime + + + align:start position:0% +which means that Theta I is B Prime +inverse + + align:start position:0% +inverse + + + align:start position:0% +inverse +of + + align:start position:0% +of + + + align:start position:0% +of +mui okay so that's what we got from this + + align:start position:0% +mui okay so that's what we got from this + + + align:start position:0% +mui okay so that's what we got from this +you know derivative of the log + + align:start position:0% +you know derivative of the log + + + align:start position:0% +you know derivative of the log +likelihood equal to zero that gave us + + align:start position:0% +likelihood equal to zero that gave us + + + align:start position:0% +likelihood equal to zero that gave us +this guy I invert it and now I know that + + align:start position:0% +this guy I invert it and now I know that + + + align:start position:0% +this guy I invert it and now I know that +mui is G inverse of x i + + align:start position:0% + + + + align:start position:0% + +beta so this composition of B Prime + + align:start position:0% +beta so this composition of B Prime + + + align:start position:0% +beta so this composition of B Prime +inverse and G inverse is actually just + + align:start position:0% +inverse and G inverse is actually just + + + align:start position:0% +inverse and G inverse is actually just +the composition of G with B + + align:start position:0% + + + + align:start position:0% + +Prime everybody's comfortable with this + + align:start position:0% +Prime everybody's comfortable with this + + + align:start position:0% +Prime everybody's comfortable with this +notation the little + + align:start position:0% +notation the little + + + align:start position:0% +notation the little +circle any question about this all right + + align:start position:0% +circle any question about this all right + + + align:start position:0% +circle any question about this all right +just means that I first apply B Prime + + align:start position:0% +just means that I first apply B Prime + + + align:start position:0% +just means that I first apply B Prime +well actually it's the inverse but if I + + align:start position:0% +well actually it's the inverse but if I + + + align:start position:0% +well actually it's the inverse but if I +look at a function G composed with B + + align:start position:0% +look at a function G composed with B + + + align:start position:0% +look at a function G composed with B +Prime I first apply g g b Prime of X is + + align:start position:0% +Prime I first apply g g b Prime of X is + + + align:start position:0% +Prime I first apply g g b Prime of X is +just G of B Prime of + + align:start position:0% +just G of B Prime of + + + align:start position:0% +just G of B Prime of +X okay okay and then I take the inverse + + align:start position:0% +X okay okay and then I take the inverse + + + align:start position:0% +X okay okay and then I take the inverse +of this function which is first take G + + align:start position:0% +of this function which is first take G + + + align:start position:0% +of this function which is first take G +inverse and then take B Prime + + align:start position:0% + + + + align:start position:0% + +inverse okay so now I have everywhere I + + align:start position:0% +inverse okay so now I have everywhere I + + + align:start position:0% +inverse okay so now I have everywhere I +saw Theta now I see this function of + + align:start position:0% +saw Theta now I see this function of + + + align:start position:0% +saw Theta now I see this function of +beta so I could technically plug that in + + align:start position:0% +beta so I could technically plug that in + + + align:start position:0% +beta so I could technically plug that in +of course it's a little painful to have + + align:start position:0% +of course it's a little painful to have + + + align:start position:0% +of course it's a little painful to have +to write G Circle beta Prime all the + + align:start position:0% +to write G Circle beta Prime all the + + + align:start position:0% +to write G Circle beta Prime all the +time so I'm going to give this guy name + + align:start position:0% +time so I'm going to give this guy name + + + align:start position:0% +time so I'm going to give this guy name +and uh so you're just going to Define + + align:start position:0% + + + + align:start position:0% + +H which is g b Prime + + align:start position:0% +H which is g b Prime + + + align:start position:0% +H which is g b Prime +inverse so that Theta I is simply h of + + align:start position:0% +inverse so that Theta I is simply h of + + + align:start position:0% +inverse so that Theta I is simply h of +XI transpose + + align:start position:0% +XI transpose + + + align:start position:0% +XI transpose +beta okay I could give it a name you + + align:start position:0% +beta okay I could give it a name you + + + align:start position:0% +beta okay I could give it a name you +know let's call but let's just call it + + align:start position:0% +know let's call but let's just call it + + + align:start position:0% +know let's call but let's just call it +that on the H + + align:start position:0% + + + + align:start position:0% + +function so there's something which is + + align:start position:0% +function so there's something which is + + + align:start position:0% +function so there's something which is +nice about this H function is that + + align:start position:0% +nice about this H function is that + + + align:start position:0% +nice about this H function is that +f g is is the canonical + + align:start position:0% + + + + align:start position:0% + +link what is the canonical + + align:start position:0% + + + + align:start position:0% + +link right so it's what is it canonical + + align:start position:0% +link right so it's what is it canonical + + + align:start position:0% +link right so it's what is it canonical +to canonical link is canonical to a + + align:start position:0% +to canonical link is canonical to a + + + align:start position:0% +to canonical link is canonical to a +particular distribution in the canonical + + align:start position:0% +particular distribution in the canonical + + + align:start position:0% +particular distribution in the canonical +exponential family right a canonical + + align:start position:0% +exponential family right a canonical + + + align:start position:0% +exponential family right a canonical +exponential family is completely + + align:start position:0% +exponential family is completely + + + align:start position:0% +exponential family is completely +characterized by the function B which + + align:start position:0% +characterized by the function B which + + + align:start position:0% +characterized by the function B which +means that if if I want to talk about + + align:start position:0% +means that if if I want to talk about + + + align:start position:0% +means that if if I want to talk about +DEC canonical link all I need to tell + + align:start position:0% +DEC canonical link all I need to tell + + + align:start position:0% +DEC canonical link all I need to tell +you is how it depends on + + align:start position:0% +you is how it depends on + + + align:start position:0% +you is how it depends on +B so what is g as a function of + + align:start position:0% +B so what is g as a function of + + + align:start position:0% +B so what is g as a function of +B + + align:start position:0% +B + + + align:start position:0% +B +what B + + align:start position:0% +what B + + + align:start position:0% +what B +inverse B Prime inverse right so this is + + align:start position:0% +inverse B Prime inverse right so this is + + + align:start position:0% +inverse B Prime inverse right so this is +G is equal to B Prime inverse which + + align:start position:0% +G is equal to B Prime inverse which + + + align:start position:0% +G is equal to B Prime inverse which +means that if G is composed with B Prime + + align:start position:0% +means that if G is composed with B Prime + + + align:start position:0% +means that if G is composed with B Prime +that means this is just the identity + + align:start position:0% + + + + align:start position:0% + +so H is the + + align:start position:0% + + + + align:start position:0% + +identity so + + align:start position:0% +identity so + + + align:start position:0% +identity so +h of X I transpose beta is simply X I + + align:start position:0% +h of X I transpose beta is simply X I + + + align:start position:0% +h of X I transpose beta is simply X I +transpose beta and it's true that the + + align:start position:0% +transpose beta and it's true that the + + + align:start position:0% +transpose beta and it's true that the +way we introduced the canonical length + + align:start position:0% +way we introduced the canonical length + + + align:start position:0% +way we introduced the canonical length +was just the function for which we model + + align:start position:0% +was just the function for which we model + + + align:start position:0% +was just the function for which we model +directly Theta I as X I transpose beta + + align:start position:0% +directly Theta I as X I transpose beta + + + align:start position:0% +directly Theta I as X I transpose beta +right which is we can read off here + + align:start position:0% +right which is we can read off here + + + align:start position:0% +right which is we can read off here +right so Theta I is simply XI transpose + + align:start position:0% +right so Theta I is simply XI transpose + + + align:start position:0% +right so Theta I is simply XI transpose +beta so now for example if I go back to + + align:start position:0% +beta so now for example if I go back to + + + align:start position:0% +beta so now for example if I go back to +this uh to my log + + align:start position:0% +this uh to my log + + + align:start position:0% +this uh to my log +likelihood uh which I know so if I go + + align:start position:0% +likelihood uh which I know so if I go + + + align:start position:0% +likelihood uh which I know so if I go +back to my log likelihood right so if I + + align:start position:0% +back to my log likelihood right so if I + + + align:start position:0% +back to my log likelihood right so if I +look + + align:start position:0% +look + + + align:start position:0% +look +log + + align:start position:0% + + + + align:start position:0% + +likelihood so the log likelihood is sum + + align:start position:0% +likelihood so the log likelihood is sum + + + align:start position:0% +likelihood so the log likelihood is sum +of the log of the + + align:start position:0% +of the log of the + + + align:start position:0% +of the log of the +densities so it's sum from I = 1 to n of + + align:start position:0% +densities so it's sum from I = 1 to n of + + + align:start position:0% +densities so it's sum from I = 1 to n of +log of + + align:start position:0% +log of + + + align:start position:0% +log of +exponential y i Theta I minus B Theta I + + align:start position:0% +exponential y i Theta I minus B Theta I + + + align:start position:0% +exponential y i Theta I minus B Theta I +/ 5 plus C of y i + + align:start position:0% +/ 5 plus C of y i + + + align:start position:0% +/ 5 plus C of y i +f right so this term that does not + + align:start position:0% +f right so this term that does not + + + align:start position:0% +f right so this term that does not +depend on + + align:start position:0% +depend on + + + align:start position:0% +depend on +Theta so I have two things first of all + + align:start position:0% +Theta so I have two things first of all + + + align:start position:0% +Theta so I have two things first of all +the log and the and the exponential are + + align:start position:0% +the log and the and the exponential are + + + align:start position:0% +the log and the and the exponential are +going to cancel each other and second I + + align:start position:0% +going to cancel each other and second I + + + align:start position:0% +going to cancel each other and second I +actually know that Theta is just a + + align:start position:0% +actually know that Theta is just a + + + align:start position:0% +actually know that Theta is just a +function of B + + align:start position:0% +function of B + + + align:start position:0% +function of B +and it has this form Theta I is H of X I + + align:start position:0% +and it has this form Theta I is H of X I + + + align:start position:0% +and it has this form Theta I is H of X I +transpose beta and that's my modeling + + align:start position:0% +transpose beta and that's my modeling + + + align:start position:0% +transpose beta and that's my modeling +assumption so this is actually equal to + + align:start position:0% +assumption so this is actually equal to + + + align:start position:0% +assumption so this is actually equal to +the sum from I 1 to n of + + align:start position:0% +the sum from I 1 to n of + + + align:start position:0% +the sum from I 1 to n of +Yi and then here I'm going to write h of + + align:start position:0% +Yi and then here I'm going to write h of + + + align:start position:0% +Yi and then here I'm going to write h of +XI transpose beta minus B of H of X I + + align:start position:0% +XI transpose beta minus B of H of X I + + + align:start position:0% +XI transpose beta minus B of H of X I +transpose beta divided by + + align:start position:0% +transpose beta divided by + + + align:start position:0% +transpose beta divided by +F and then I have again this + + align:start position:0% +F and then I have again this + + + align:start position:0% +F and then I have again this +function C of Yi + + align:start position:0% +function C of Yi + + + align:start position:0% +function C of Yi +which again won't matter because when + + align:start position:0% +which again won't matter because when + + + align:start position:0% +which again won't matter because when +I'm going to try to maximize this thing + + align:start position:0% +I'm going to try to maximize this thing + + + align:start position:0% +I'm going to try to maximize this thing +this is just playing the role of a + + align:start position:0% +this is just playing the role of a + + + align:start position:0% +this is just playing the role of a +constant that's Shifting the entire + + align:start position:0% +constant that's Shifting the entire + + + align:start position:0% +constant that's Shifting the entire +function so in particular the org Max is + + align:start position:0% +function so in particular the org Max is + + + align:start position:0% +function so in particular the org Max is +going to be exactly what it was okay so + + align:start position:0% +going to be exactly what it was okay so + + + align:start position:0% +going to be exactly what it was okay so +this thing is really not going to matter + + align:start position:0% +this thing is really not going to matter + + + align:start position:0% +this thing is really not going to matter +for me I'm keeping track of it and + + align:start position:0% +for me I'm keeping track of it and + + + align:start position:0% +for me I'm keeping track of it and +actually if you look here it's + + align:start position:0% +actually if you look here it's + + + align:start position:0% +actually if you look here it's +gone right it's gone because it does not + + align:start position:0% +gone right it's gone because it does not + + + align:start position:0% +gone right it's gone because it does not +matter so let's just pretend it's not + + align:start position:0% +matter so let's just pretend it's not + + + align:start position:0% +matter so let's just pretend it's not +here because it won't matter when I'm + + align:start position:0% +here because it won't matter when I'm + + + align:start position:0% +here because it won't matter when I'm +trying to maximize + + align:start position:0% + + + + align:start position:0% + +lik + + align:start position:0% +lik + + + align:start position:0% +lik +okay well it's here up to a constant + + align:start position:0% +okay well it's here up to a constant + + + align:start position:0% +okay well it's here up to a constant +term it says that's the constant + + align:start position:0% +term it says that's the constant + + + align:start position:0% +term it says that's the constant +term all right any + + align:start position:0% +term all right any + + + align:start position:0% +term all right any +question all I'm doing here is + + align:start position:0% +question all I'm doing here is + + + align:start position:0% +question all I'm doing here is +replacing my likelihood as a function of + + align:start position:0% +replacing my likelihood as a function of + + + align:start position:0% +replacing my likelihood as a function of +theta I so if I had one Theta I per + + align:start position:0% +theta I so if I had one Theta I per + + + align:start position:0% +theta I so if I had one Theta I per +observation again this would not help me + + align:start position:0% +observation again this would not help me + + + align:start position:0% +observation again this would not help me +very much but if I assume that they're + + align:start position:0% +very much but if I assume that they're + + + align:start position:0% +very much but if I assume that they're +all linked together by saying that Theta + + align:start position:0% +all linked together by saying that Theta + + + align:start position:0% +all linked together by saying that Theta +I is of the form XI transpose beta or h + + align:start position:0% +I is of the form XI transpose beta or h + + + align:start position:0% +I is of the form XI transpose beta or h +of XI transpose beta if I'm not using + + align:start position:0% +of XI transpose beta if I'm not using + + + align:start position:0% +of XI transpose beta if I'm not using +the the canonical length then I can hope + + align:start position:0% +the the canonical length then I can hope + + + align:start position:0% +the the canonical length then I can hope +to make some + + align:start position:0% +to make some + + + align:start position:0% +to make some +estimation all right + + align:start position:0% +estimation all right + + + align:start position:0% +estimation all right +so again if I have the canonical link H + + align:start position:0% +so again if I have the canonical link H + + + align:start position:0% +so again if I have the canonical link H +is the identity so I'm left only with y + + align:start position:0% +is the identity so I'm left only with y + + + align:start position:0% +is the identity so I'm left only with y +i time x I transpose beta and then I + + align:start position:0% +i time x I transpose beta and then I + + + align:start position:0% +i time x I transpose beta and then I +have B of XI transpose beta not B + + align:start position:0% +have B of XI transpose beta not B + + + align:start position:0% +have B of XI transpose beta not B +composed with + + align:start position:0% +composed with + + + align:start position:0% +composed with +h because H is the + + align:start position:0% +h because H is the + + + align:start position:0% +h because H is the +identity which is fairly simple right + + align:start position:0% +identity which is fairly simple right + + + align:start position:0% +identity which is fairly simple right +why is it it simple well let's actually + + align:start position:0% +why is it it simple well let's actually + + + align:start position:0% +why is it it simple well let's actually +focus on this guy for one + + align:start position:0% +focus on this guy for one + + + align:start position:0% +focus on this guy for one +second uh so let me write it down so we + + align:start position:0% +second uh so let me write it down so we + + + align:start position:0% +second uh so let me write it down so we +know what we're talking + + align:start position:0% + + + + align:start position:0% + +about so we just showed that the log + + align:start position:0% +about so we just showed that the log + + + align:start position:0% +about so we just showed that the log +likelihood when I + + align:start position:0% +likelihood when I + + + align:start position:0% +likelihood when I +use the canonical link so that H is + + align:start position:0% +use the canonical link so that H is + + + align:start position:0% +use the canonical link so that H is +equal to the identity the log likelihood + + align:start position:0% +equal to the identity the log likelihood + + + align:start position:0% +equal to the identity the log likelihood +actually takes the form Ln and it + + align:start position:0% +actually takes the form Ln and it + + + align:start position:0% +actually takes the form Ln and it +depends on a bunch of stuff but let's + + align:start position:0% +depends on a bunch of stuff but let's + + + align:start position:0% +depends on a bunch of stuff but let's +just make it depend only on the + + align:start position:0% +just make it depend only on the + + + align:start position:0% +just make it depend only on the +parameter that we care about which is + + align:start position:0% +parameter that we care about which is + + + align:start position:0% +parameter that we care about which is +beta all right so this is of the form L + + align:start position:0% +beta all right so this is of the form L + + + align:start position:0% +beta all right so this is of the form L +of beta and that's equal to what is the + + align:start position:0% +of beta and that's equal to what is the + + + align:start position:0% +of beta and that's equal to what is the +sum from I = 1 to n of y i x i transpose + + align:start position:0% +sum from I = 1 to n of y i x i transpose + + + align:start position:0% +sum from I = 1 to n of y i x i transpose +beta minus let me put the F here and + + align:start position:0% +beta minus let me put the F here and + + + align:start position:0% +beta minus let me put the F here and +then I'm going to have minus B of X + + align:start position:0% +then I'm going to have minus B of X + + + align:start position:0% +then I'm going to have minus B of X +I transpose + + align:start position:0% + + + + align:start position:0% + +beta okay okay and Fe we know is uh some + + align:start position:0% +beta okay okay and Fe we know is uh some + + + align:start position:0% +beta okay okay and Fe we know is uh some +known positive term so again optimizing + + align:start position:0% +known positive term so again optimizing + + + align:start position:0% +known positive term so again optimizing +a function plus some constant or + + align:start position:0% +a function plus some constant or + + + align:start position:0% +a function plus some constant or +optimizing a function times a constant + + align:start position:0% +optimizing a function times a constant + + + align:start position:0% +optimizing a function times a constant +that's not going to change much either + + align:start position:0% +that's not going to change much either + + + align:start position:0% +that's not going to change much either +so it won't really matter to think about + + align:start position:0% +so it won't really matter to think about + + + align:start position:0% +so it won't really matter to think about +whether this F is here or not but let's + + align:start position:0% +whether this F is here or not but let's + + + align:start position:0% +whether this F is here or not but let's +just think about what this function + + align:start position:0% +just think about what this function + + + align:start position:0% +just think about what this function +looks like all right I'm trying to + + align:start position:0% +looks like all right I'm trying to + + + align:start position:0% +looks like all right I'm trying to +maximize a function I'm trying to + + align:start position:0% +maximize a function I'm trying to + + + align:start position:0% +maximize a function I'm trying to +maximize a log likelihood if it look + + align:start position:0% +maximize a log likelihood if it look + + + align:start position:0% +maximize a log likelihood if it look +like + + align:start position:0% +like + + + align:start position:0% +like +this that would be a serious problem but + + align:start position:0% +this that would be a serious problem but + + + align:start position:0% +this that would be a serious problem but +we can do like a basic you know back of + + align:start position:0% +we can do like a basic you know back of + + + align:start position:0% +we can do like a basic you know back of +the envelope uh uh guess of what the + + align:start position:0% +the envelope uh uh guess of what the + + + align:start position:0% +the envelope uh uh guess of what the +variations of this function is this + + align:start position:0% +variations of this function is this + + + align:start position:0% +variations of this function is this +first term here + + align:start position:0% +first term here + + + align:start position:0% +first term here +is in as a function of beta it's what + + align:start position:0% +is in as a function of beta it's what + + + align:start position:0% +is in as a function of beta it's what +kind of function is + + align:start position:0% +kind of function is + + + align:start position:0% +kind of function is +it it's linear right this is just X I + + align:start position:0% +it it's linear right this is just X I + + + align:start position:0% +it it's linear right this is just X I +transpose beta If I multiply beta by two + + align:start position:0% +transpose beta If I multiply beta by two + + + align:start position:0% +transpose beta If I multiply beta by two +I get twice if I add something to Beta + + align:start position:0% +I get twice if I add something to Beta + + + align:start position:0% +I get twice if I add something to Beta +it just gets added so it's a linear + + align:start position:0% +it just gets added so it's a linear + + + align:start position:0% +it just gets added so it's a linear +function of beta and so this thing is + + align:start position:0% +function of beta and so this thing is + + + align:start position:0% +function of beta and so this thing is +both convex and concave in the + + align:start position:0% +both convex and concave in the + + + align:start position:0% +both convex and concave in the +onedimensional case so think about p as + + align:start position:0% +onedimensional case so think about p as + + + align:start position:0% +onedimensional case so think about p as +being one diens that beta is a + + align:start position:0% +being one diens that beta is a + + + align:start position:0% +being one diens that beta is a +onedimensional thing those are just the + + align:start position:0% +onedimensional thing those are just the + + + align:start position:0% +onedimensional thing those are just the +function that look like this right those + + align:start position:0% +function that look like this right those + + + align:start position:0% +function that look like this right those +are linear functions they are both + + align:start position:0% +are linear functions they are both + + + align:start position:0% +are linear functions they are both +convex and + + align:start position:0% +convex and + + + align:start position:0% +convex and +concave so this is not going to matter + + align:start position:0% +concave so this is not going to matter + + + align:start position:0% +concave so this is not going to matter +when it comes to the convexity of My + + align:start position:0% +when it comes to the convexity of My + + + align:start position:0% +when it comes to the convexity of My +overall function because I'm just adding + + align:start position:0% +overall function because I'm just adding + + + align:start position:0% +overall function because I'm just adding +something which is just a line and so if + + align:start position:0% +something which is just a line and so if + + + align:start position:0% +something which is just a line and so if +I started with convex it's going to stay + + align:start position:0% +I started with convex it's going to stay + + + align:start position:0% +I started with convex it's going to stay +convex if I started with concave it's + + align:start position:0% +convex if I started with concave it's + + + align:start position:0% +convex if I started with concave it's +going to stay concave and if I started + + align:start position:0% +going to stay concave and if I started + + + align:start position:0% +going to stay concave and if I started +with something which is both is going to + + align:start position:0% +with something which is both is going to + + + align:start position:0% +with something which is both is going to +stay both meaning neither cannot be both + + align:start position:0% +stay both meaning neither cannot be both + + + align:start position:0% +stay both meaning neither cannot be both +ah yeah so if you're neither conx or + + align:start position:0% +ah yeah so if you're neither conx or + + + align:start position:0% +ah yeah so if you're neither conx or +concave adding this linear so this will + + align:start position:0% +concave adding this linear so this will + + + align:start position:0% +concave adding this linear so this will +not really matter if I want to + + align:start position:0% +not really matter if I want to + + + align:start position:0% +not really matter if I want to +understand what my function looks like I + + align:start position:0% +understand what my function looks like I + + + align:start position:0% +understand what my function looks like I +need to understand what B of XI + + align:start position:0% +need to understand what B of XI + + + align:start position:0% +need to understand what B of XI +transpose beta does again the XI + + align:start position:0% +transpose beta does again the XI + + + align:start position:0% +transpose beta does again the XI +transpose beta no impact it's a linear + + align:start position:0% +transpose beta no impact it's a linear + + + align:start position:0% +transpose beta no impact it's a linear +function in terms of convexity it's not + + align:start position:0% +function in terms of convexity it's not + + + align:start position:0% +function in terms of convexity it's not +going to play any role so I really need + + align:start position:0% +going to play any role so I really need + + + align:start position:0% +going to play any role so I really need +to understand what my function B looks + + align:start position:0% +to understand what my function B looks + + + align:start position:0% +to understand what my function B looks +like what do we know about B + + align:start position:0% + + + + align:start position:0% + +again so we know that b + + align:start position:0% + + + + align:start position:0% + +Prime of theta is equal to Mu + + align:start position:0% +Prime of theta is equal to Mu + + + align:start position:0% +Prime of theta is equal to Mu +right well you know the mean of um of a + + align:start position:0% +right well you know the mean of um of a + + + align:start position:0% +right well you know the mean of um of a +random variable in the canonical + + align:start position:0% +random variable in the canonical + + + align:start position:0% +random variable in the canonical +exponential family can be a positive or + + align:start position:0% +exponential family can be a positive or + + + align:start position:0% +exponential family can be a positive or +negative number this really does not + + align:start position:0% +negative number this really does not + + + align:start position:0% +negative number this really does not +tell me anything that can be really + + align:start position:0% +tell me anything that can be really + + + align:start position:0% +tell me anything that can be really +anything however if I look at the second + + align:start position:0% +anything however if I look at the second + + + align:start position:0% +anything however if I look at the second +derivative of uh of B I know that this + + align:start position:0% +derivative of uh of B I know that this + + + align:start position:0% +derivative of uh of B I know that this +is what this is the + + align:start position:0% +is what this is the + + + align:start position:0% +is what this is the +variance of Y divided by + + align:start position:0% +variance of Y divided by + + + align:start position:0% +variance of Y divided by +five right that was my dispersion + + align:start position:0% +five right that was my dispersion + + + align:start position:0% +five right that was my dispersion +parameter the variance was equal to 5 * + + align:start position:0% +parameter the variance was equal to 5 * + + + align:start position:0% +parameter the variance was equal to 5 * +B prime prime so we know that if Theta + + align:start position:0% +B prime prime so we know that if Theta + + + align:start position:0% +B prime prime so we know that if Theta +is not degenerate meaning that you know + + align:start position:0% +is not degenerate meaning that you know + + + align:start position:0% +is not degenerate meaning that you know +the density does not take value Infinity + + align:start position:0% +the density does not take value Infinity + + + align:start position:0% +the density does not take value Infinity +at only one point this thing is actually + + align:start position:0% +at only one point this thing is actually + + + align:start position:0% +at only one point this thing is actually +positive and clearly when you have + + align:start position:0% +positive and clearly when you have + + + align:start position:0% +positive and clearly when you have +something that looks like this unless + + align:start position:0% +something that looks like this unless + + + align:start position:0% +something that looks like this unless +you have some crazy stuff happening with + + align:start position:0% +you have some crazy stuff happening with + + + align:start position:0% +you have some crazy stuff happening with +five being equal to zero or anything + + align:start position:0% +five being equal to zero or anything + + + align:start position:0% +five being equal to zero or anything +that's not normal then you will see that + + align:start position:0% +that's not normal then you will see that + + + align:start position:0% +that's not normal then you will see that +you're not degenerate so this thing is + + align:start position:0% +you're not degenerate so this thing is + + + align:start position:0% +you're not degenerate so this thing is +strictly positive and we've said several + + align:start position:0% +strictly positive and we've said several + + + align:start position:0% +strictly positive and we've said several +time that if B prime prime is positive + + align:start position:0% +time that if B prime prime is positive + + + align:start position:0% +time that if B prime prime is positive +then that means that's you know that's + + align:start position:0% +then that means that's you know that's + + + align:start position:0% +then that means that's you know that's +the derivative of B prime meaning that b + + align:start position:0% +the derivative of B prime meaning that b + + + align:start position:0% +the derivative of B prime meaning that b +Prime is increasing and B Prime is + + align:start position:0% +Prime is increasing and B Prime is + + + align:start position:0% +Prime is increasing and B Prime is +increasing is just the same thing as + + align:start position:0% +increasing is just the same thing as + + + align:start position:0% +increasing is just the same thing as +saying that b is convex right so that + + align:start position:0% +saying that b is convex right so that + + + align:start position:0% +saying that b is convex right so that +implies that + + align:start position:0% +implies that + + + align:start position:0% +implies that +b is strictly convex and the strictly + + align:start position:0% +b is strictly convex and the strictly + + + align:start position:0% +b is strictly convex and the strictly +means comes from the fact that this is a + + align:start position:0% +means comes from the fact that this is a + + + align:start position:0% +means comes from the fact that this is a +strict sign well I should not do that + + align:start position:0% +strict sign well I should not do that + + + align:start position:0% +strict sign well I should not do that +because now it's no longer all right so + + align:start position:0% +because now it's no longer all right so + + + align:start position:0% +because now it's no longer all right so +it's just a strict sign meaning that the + + align:start position:0% +it's just a strict sign meaning that the + + + align:start position:0% +it's just a strict sign meaning that the +function this is not strictly convex + + align:start position:0% +function this is not strictly convex + + + align:start position:0% +function this is not strictly convex +because it's linear strictly convex + + align:start position:0% +because it's linear strictly convex + + + align:start position:0% +because it's linear strictly convex +means there's always some curvature + + align:start position:0% +means there's always some curvature + + + align:start position:0% +means there's always some curvature +everywhere so now I have this thing + + align:start position:0% +everywhere so now I have this thing + + + align:start position:0% +everywhere so now I have this thing +that's linear minus something that's + + align:start position:0% +that's linear minus something that's + + + align:start position:0% +that's linear minus something that's +convex something that's negative + + align:start position:0% +convex something that's negative + + + align:start position:0% +convex something that's negative +something convex is concave so this + + align:start position:0% +something convex is concave so this + + + align:start position:0% +something convex is concave so this +thing is linear plus concave so it is + + align:start position:0% +thing is linear plus concave so it is + + + align:start position:0% +thing is linear plus concave so it is +concave so I know just by looking at + + align:start position:0% +concave so I know just by looking at + + + align:start position:0% +concave so I know just by looking at +this that Ln of beta which of course is + + align:start position:0% +this that Ln of beta which of course is + + + align:start position:0% +this that Ln of beta which of course is +something that lives in RP but if I saw + + align:start position:0% +something that lives in RP but if I saw + + + align:start position:0% +something that lives in RP but if I saw +it living in R1 it would look like this + + align:start position:0% +it living in R1 it would look like this + + + align:start position:0% +it living in R1 it would look like this +and if I saw living it in R2 it would + + align:start position:0% +and if I saw living it in R2 it would + + + align:start position:0% +and if I saw living it in R2 it would +look like a dome like this and it the + + align:start position:0% +look like a dome like this and it the + + + align:start position:0% +look like a dome like this and it the +fact that it's strict is also telling me + + align:start position:0% +fact that it's strict is also telling me + + + align:start position:0% +fact that it's strict is also telling me +that there's actually unique + + align:start position:0% +that there's actually unique + + + align:start position:0% +that there's actually unique +maximizer so there's unique maximizer in + + align:start position:0% +maximizer so there's unique maximizer in + + + align:start position:0% +maximizer so there's unique maximizer in +XI transpose beta but not in beta + + align:start position:0% +XI transpose beta but not in beta + + + align:start position:0% +XI transpose beta but not in beta +necessarily we're going to need extra + + align:start position:0% +necessarily we're going to need extra + + + align:start position:0% +necessarily we're going to need extra +assumptions for + + align:start position:0% +assumptions for + + + align:start position:0% +assumptions for +this okay so this is what I say here the + + align:start position:0% +this okay so this is what I say here the + + + align:start position:0% +this okay so this is what I say here the +log likelihood is strictly concave and + + align:start position:0% +log likelihood is strictly concave and + + + align:start position:0% +log likelihood is strictly concave and +so as a consequence under extra + + align:start position:0% +so as a consequence under extra + + + align:start position:0% +so as a consequence under extra +assumptions on the XI because of course + + align:start position:0% +assumptions on the XI because of course + + + align:start position:0% +assumptions on the XI because of course +if the XIs are not uh if the XIs are all + + align:start position:0% +if the XIs are not uh if the XIs are all + + + align:start position:0% +if the XIs are not uh if the XIs are all +the + + align:start position:0% +the + + + align:start position:0% +the +same right so that like if the entries + + align:start position:0% +same right so that like if the entries + + + align:start position:0% +same right so that like if the entries +of XIs so if x I is equal to + + align:start position:0% +of XIs so if x I is equal to + + + align:start position:0% +of XIs so if x I is equal to +11111 then X I transpose beta is just + + align:start position:0% +11111 then X I transpose beta is just + + + align:start position:0% +11111 then X I transpose beta is just +the sum of the betas and I will be of + + align:start position:0% +the sum of the betas and I will be of + + + align:start position:0% +the sum of the betas and I will be of +the beta eyes I will be strictly concave + + align:start position:0% +the beta eyes I will be strictly concave + + + align:start position:0% +the beta eyes I will be strictly concave +in those guys but certainly not in the + + align:start position:0% +in those guys but certainly not in the + + + align:start position:0% +in those guys but certainly not in the +individual entries okay so I need extra + + align:start position:0% +individual entries okay so I need extra + + + align:start position:0% +individual entries okay so I need extra +thing on my XI so that this happens just + + align:start position:0% +thing on my XI so that this happens just + + + align:start position:0% +thing on my XI so that this happens just +like we needed the Matrix capital X in + + align:start position:0% +like we needed the Matrix capital X in + + + align:start position:0% +like we needed the Matrix capital X in +the linear regression case to be a full + + align:start position:0% +the linear regression case to be a full + + + align:start position:0% +the linear regression case to be a full +rank so we could actually identify what + + align:start position:0% +rank so we could actually identify what + + + align:start position:0% +rank so we could actually identify what +beta was okay it's going to be exactly + + align:start position:0% +beta was okay it's going to be exactly + + + align:start position:0% +beta was okay it's going to be exactly +the same thing + + align:start position:0% + + + + align:start position:0% + +so uh uh so here this is when we have + + align:start position:0% +so uh uh so here this is when we have + + + align:start position:0% +so uh uh so here this is when we have +this very specific uh uh + + align:start position:0% +this very specific uh uh + + + align:start position:0% +this very specific uh uh +parameterization and the question is uh + + align:start position:0% +parameterization and the question is uh + + + align:start position:0% +parameterization and the question is uh +uh but it might not be the case if we + + align:start position:0% +uh but it might not be the case if we + + + align:start position:0% +uh but it might not be the case if we +change the parameter beta into something + + align:start position:0% +change the parameter beta into something + + + align:start position:0% +change the parameter beta into something +else okay so here the fact that we use + + align:start position:0% +else okay so here the fact that we use + + + align:start position:0% +else okay so here the fact that we use +the canonical link and Etc everything + + align:start position:0% +the canonical link and Etc everything + + + align:start position:0% +the canonical link and Etc everything +actually works really to our advantage + + align:start position:0% +actually works really to our advantage + + + align:start position:0% +actually works really to our advantage +right so that everything becomes + + align:start position:0% +right so that everything becomes + + + align:start position:0% +right so that everything becomes +strictly concave and we know exactly + + align:start position:0% +strictly concave and we know exactly + + + align:start position:0% +strictly concave and we know exactly +what's + + align:start position:0% + + + + align:start position:0% + +happening all right so I understand I + + align:start position:0% +happening all right so I understand I + + + align:start position:0% +happening all right so I understand I +went a bit fast on playing with convex + + align:start position:0% +went a bit fast on playing with convex + + + align:start position:0% +went a bit fast on playing with convex +and concave function this is not the + + align:start position:0% +and concave function this is not the + + + align:start position:0% +and concave function this is not the +purpose uh you know I could spend a + + align:start position:0% +purpose uh you know I could spend a + + + align:start position:0% +purpose uh you know I could spend a +lecture telling you oh if I add two + + align:start position:0% +lecture telling you oh if I add two + + + align:start position:0% +lecture telling you oh if I add two +concave functions then the result + + align:start position:0% +concave functions then the result + + + align:start position:0% +concave functions then the result +remains concave if I had a you know + + align:start position:0% +remains concave if I had a you know + + + align:start position:0% +remains concave if I had a you know +concave and a strictly concave then the + + align:start position:0% +concave and a strictly concave then the + + + align:start position:0% +concave and a strictly concave then the +result Still Remains strictly concave + + align:start position:0% +result Still Remains strictly concave + + + align:start position:0% +result Still Remains strictly concave +and we could spend time proving this + + align:start position:0% +and we could spend time proving this + + + align:start position:0% +and we could spend time proving this +this is was just for you to get an + + align:start position:0% +this is was just for you to get an + + + align:start position:0% +this is was just for you to get an +intuition as to why this is correct but + + align:start position:0% +intuition as to why this is correct but + + + align:start position:0% +intuition as to why this is correct but +we don't really have time to go into too + + align:start position:0% +we don't really have time to go into too + + + align:start position:0% +we don't really have time to go into too +much details one thing you can do a + + align:start position:0% +much details one thing you can do a + + + align:start position:0% +much details one thing you can do a +strictly concave function if it's in one + + align:start position:0% +strictly concave function if it's in one + + + align:start position:0% +strictly concave function if it's in one +dimension all I need to have is that the + + align:start position:0% +dimension all I need to have is that the + + + align:start position:0% +dimension all I need to have is that the +second der + + align:start position:0% +second der + + + align:start position:0% +second der +ative is strictly is strictly negative + + align:start position:0% +ative is strictly is strictly negative + + + align:start position:0% +ative is strictly is strictly negative +right that's a strictly concave function + + align:start position:0% +right that's a strictly concave function + + + align:start position:0% +right that's a strictly concave function +that was the analytic definition we had + + align:start position:0% +that was the analytic definition we had + + + align:start position:0% +that was the analytic definition we had +for strict concavity so if this was in + + align:start position:0% +for strict concavity so if this was in + + + align:start position:0% +for strict concavity so if this was in +one dimension it would look like + + align:start position:0% +one dimension it would look like + + + align:start position:0% +one dimension it would look like +this y i * x i Time beta Now Beta is + + align:start position:0% +this y i * x i Time beta Now Beta is + + + align:start position:0% +this y i * x i Time beta Now Beta is +just one number and then I would have + + align:start position:0% +just one number and then I would have + + + align:start position:0% +just one number and then I would have +minus beta x i * B and this is over all + + align:start position:0% +minus beta x i * B and this is over all + + + align:start position:0% +minus beta x i * B and this is over all +over five you take second derivatives + + align:start position:0% +over five you take second derivatives + + + align:start position:0% +over five you take second derivatives +the fact that this is linear in beta + + align:start position:0% +the fact that this is linear in beta + + + align:start position:0% +the fact that this is linear in beta +this is going to go way and here I'm + + align:start position:0% +this is going to go way and here I'm + + + align:start position:0% +this is going to go way and here I'm +just going to be left with + + align:start position:0% +just going to be left with + + + align:start position:0% +just going to be left with +minus so if I take the second + + align:start position:0% +minus so if I take the second + + + align:start position:0% +minus so if I take the second +derivative with respect to Beta this is + + align:start position:0% +derivative with respect to Beta this is + + + align:start position:0% +derivative with respect to Beta this is +going to be equal to minus B prime prime + + align:start position:0% +going to be equal to minus B prime prime + + + align:start position:0% +going to be equal to minus B prime prime +x i beta time x i^ 2 divided five so + + align:start position:0% +x i beta time x i^ 2 divided five so + + + align:start position:0% +x i beta time x i^ 2 divided five so +this is clearly positive that's that's + + align:start position:0% +this is clearly positive that's that's + + + align:start position:0% +this is clearly positive that's that's +where if XI is zero this is the generate + + align:start position:0% +where if XI is zero this is the generate + + + align:start position:0% +where if XI is zero this is the generate +so I would not get it uh then I have the + + align:start position:0% +so I would not get it uh then I have the + + + align:start position:0% +so I would not get it uh then I have the +second derivative of B Prime which I + + align:start position:0% +second derivative of B Prime which I + + + align:start position:0% +second derivative of B Prime which I +know is positive because of the variance + + align:start position:0% +know is positive because of the variance + + + align:start position:0% +know is positive because of the variance +thing that I have here divided by five + + align:start position:0% +thing that I have here divided by five + + + align:start position:0% +thing that I have here divided by five +and so that would all be fine that's for + + align:start position:0% +and so that would all be fine that's for + + + align:start position:0% +and so that would all be fine that's for +one dimension if I wanted to do this in + + align:start position:0% +one dimension if I wanted to do this in + + + align:start position:0% +one dimension if I wanted to do this in +higher dimensions and would have to say + + align:start position:0% +higher dimensions and would have to say + + + align:start position:0% +higher dimensions and would have to say +that the hen is a positive definite + + align:start position:0% +that the hen is a positive definite + + + align:start position:0% +that the hen is a positive definite +Matrix and that's maybe a bit beyond + + align:start position:0% +Matrix and that's maybe a bit beyond + + + align:start position:0% +Matrix and that's maybe a bit beyond +what this course + + align:start position:0% + + + + align:start position:0% + +is + + align:start position:0% +is + + + align:start position:0% +is +okay so in the rest of this + + align:start position:0% +okay so in the rest of this + + + align:start position:0% +okay so in the rest of this +chapter uh I will do what I did not do + + align:start position:0% +chapter uh I will do what I did not do + + + align:start position:0% +chapter uh I will do what I did not do +uh when we talked about maximum + + align:start position:0% +uh when we talked about maximum + + + align:start position:0% +uh when we talked about maximum +likelihood and and uh what we're going + + align:start position:0% +likelihood and and uh what we're going + + + align:start position:0% +likelihood and and uh what we're going +to do is we're going to actually show + + align:start position:0% +to do is we're going to actually show + + + align:start position:0% +to do is we're going to actually show +how to do this maximization right so + + align:start position:0% +how to do this maximization right so + + + align:start position:0% +how to do this maximization right so +here we know that the function is + + align:start position:0% +here we know that the function is + + + align:start position:0% +here we know that the function is +concave but what it looks like + + align:start position:0% +concave but what it looks like + + + align:start position:0% +concave but what it looks like +specifically depends on what B is and + + align:start position:0% +specifically depends on what B is and + + + align:start position:0% +specifically depends on what B is and +for different B's I'm going to have + + align:start position:0% +for different B's I'm going to have + + + align:start position:0% +for different B's I'm going to have +different things to do just like when I + + align:start position:0% +different things to do just like when I + + + align:start position:0% +different things to do just like when I +was talking about maximum likelihood + + align:start position:0% +was talking about maximum likelihood + + + align:start position:0% +was talking about maximum likelihood +estimation if I had a concave uh log + + align:start position:0% +estimation if I had a concave uh log + + + align:start position:0% +estimation if I had a concave uh log +likelihood function I could optimize it + + align:start position:0% +likelihood function I could optimize it + + + align:start position:0% +likelihood function I could optimize it +but depending on what the function is I + + align:start position:0% +but depending on what the function is I + + + align:start position:0% +but depending on what the function is I +would actually need some algorithms + + align:start position:0% +would actually need some algorithms + + + align:start position:0% +would actually need some algorithms +that's maybe working better on some + + align:start position:0% +that's maybe working better on some + + + align:start position:0% +that's maybe working better on some +function than others now here I don't + + align:start position:0% +function than others now here I don't + + + align:start position:0% +function than others now here I don't +have random things I have the B is the + + align:start position:0% +have random things I have the B is the + + + align:start position:0% +have random things I have the B is the +cumulant generating function of a + + align:start position:0% +cumulant generating function of a + + + align:start position:0% +cumulant generating function of a +canonical exponential family and there + + align:start position:0% +canonical exponential family and there + + + align:start position:0% +canonical exponential family and there +is a way for me to sort of Leverage that + + align:start position:0% +is a way for me to sort of Leverage that + + + align:start position:0% +is a way for me to sort of Leverage that +right so not only is there's the the B + + align:start position:0% +right so not only is there's the the B + + + align:start position:0% +right so not only is there's the the B +part but there's also the linear part + + align:start position:0% +part but there's also the linear part + + + align:start position:0% +part but there's also the linear part +and if I start trying to use that I'm + + align:start position:0% +and if I start trying to use that I'm + + + align:start position:0% +and if I start trying to use that I'm +actually going to be able to devise very + + align:start position:0% +actually going to be able to devise very + + + align:start position:0% +actually going to be able to devise very +specific optimization algorithms and the + + align:start position:0% +specific optimization algorithms and the + + + align:start position:0% +specific optimization algorithms and the +way I'm going to be able to do this is + + align:start position:0% +way I'm going to be able to do this is + + + align:start position:0% +way I'm going to be able to do this is +by thinking of simple blackbox + + align:start position:0% +by thinking of simple blackbox + + + align:start position:0% +by thinking of simple blackbox +optimization to which I can actually + + align:start position:0% +optimization to which I can actually + + + align:start position:0% +optimization to which I can actually +technically feed any function but it's + + align:start position:0% +technically feed any function but it's + + + align:start position:0% +technically feed any function but it's +going to turn out that the iterations of + + align:start position:0% +going to turn out that the iterations of + + + align:start position:0% +going to turn out that the iterations of +this iterative algorithms are going to + + align:start position:0% +this iterative algorithms are going to + + + align:start position:0% +this iterative algorithms are going to +look + + align:start position:0% +look + + + align:start position:0% +look +very familiar uh when we uh when we just + + align:start position:0% +very familiar uh when we uh when we just + + + align:start position:0% +very familiar uh when we uh when we just +plug in the particular values of B of + + align:start position:0% +plug in the particular values of B of + + + align:start position:0% +plug in the particular values of B of +the log likelihood that we have for this + + align:start position:0% +the log likelihood that we have for this + + + align:start position:0% +the log likelihood that we have for this +problem and so the three methods we're + + align:start position:0% +problem and so the three methods we're + + + align:start position:0% +problem and so the three methods we're +going to talk about going from more + + align:start position:0% +going to talk about going from more + + + align:start position:0% +going to talk about going from more +black box meaning you can basically + + align:start position:0% +black box meaning you can basically + + + align:start position:0% +black box meaning you can basically +stuff it any function is going to work + + align:start position:0% +stuff it any function is going to work + + + align:start position:0% +stuff it any function is going to work +any concave function is going to work + + align:start position:0% +any concave function is going to work + + + align:start position:0% +any concave function is going to work +all the way to this is working + + align:start position:0% +all the way to this is working + + + align:start position:0% +all the way to this is working +specifically for General linear models + + align:start position:0% +specifically for General linear models + + + align:start position:0% +specifically for General linear models +are Newton rafon method who's already + + align:start position:0% +are Newton rafon method who's already + + + align:start position:0% +are Newton rafon method who's already +heard about the Newton rafon method + + align:start position:0% +heard about the Newton rafon method + + + align:start position:0% +heard about the Newton rafon method +right so you know any that's probably + + align:start position:0% +right so you know any that's probably + + + align:start position:0% +right so you know any that's probably +some people actually learned this + + align:start position:0% +some people actually learned this + + + align:start position:0% +some people actually learned this +algorithm without even knowing the word + + align:start position:0% +algorithm without even knowing the word + + + align:start position:0% +algorithm without even knowing the word +algorithm right it's a function that I + + align:start position:0% +algorithm right it's a function that I + + + align:start position:0% +algorithm right it's a function that I +mean typically it's supposed to be + + align:start position:0% +mean typically it's supposed to be + + + align:start position:0% +mean typically it's supposed to be +finding roots of functions but finding + + align:start position:0% +finding roots of functions but finding + + + align:start position:0% +finding roots of functions but finding +the root of a function of a derivative + + align:start position:0% +the root of a function of a derivative + + + align:start position:0% +the root of a function of a derivative +is the same as finding the minimum of a + + align:start position:0% +is the same as finding the minimum of a + + + align:start position:0% +is the same as finding the minimum of a +function uh so uh that's the first + + align:start position:0% +function uh so uh that's the first + + + align:start position:0% +function uh so uh that's the first +blackbox method I mean uh it's it's it's + + align:start position:0% +blackbox method I mean uh it's it's it's + + + align:start position:0% +blackbox method I mean uh it's it's it's +pretty old and then there's something + + align:start position:0% +pretty old and then there's something + + + align:start position:0% +pretty old and then there's something +that's very specific to what we're doing + + align:start position:0% +that's very specific to what we're doing + + + align:start position:0% +that's very specific to what we're doing +which is called so this Newton raon + + align:start position:0% +which is called so this Newton raon + + + align:start position:0% +which is called so this Newton raon +method is going to involve the hhen of + + align:start position:0% +method is going to involve the hhen of + + + align:start position:0% +method is going to involve the hhen of +our log likelihood and uh since we know + + align:start position:0% +our log likelihood and uh since we know + + + align:start position:0% +our log likelihood and uh since we know +something about the hhen for a + + align:start position:0% +something about the hhen for a + + + align:start position:0% +something about the hhen for a +particular problem we're going to be + + align:start position:0% +particular problem we're going to be + + + align:start position:0% +particular problem we're going to be +able to move on to Fisher scoring and + + align:start position:0% +able to move on to Fisher scoring and + + + align:start position:0% +able to move on to Fisher scoring and +the word Fisher here is actually exactly + + align:start position:0% +the word Fisher here is actually exactly + + + align:start position:0% +the word Fisher here is actually exactly +coming from Fisher information so the + + align:start position:0% +coming from Fisher information so the + + + align:start position:0% +coming from Fisher information so the +hen is going to involve the Fisher + + align:start position:0% +hen is going to involve the Fisher + + + align:start position:0% +hen is going to involve the Fisher +information and uh finally uh we will + + align:start position:0% +information and uh finally uh we will + + + align:start position:0% +information and uh finally uh we will +talk about iteratively Reed Le squares + + align:start position:0% +talk about iteratively Reed Le squares + + + align:start position:0% +talk about iteratively Reed Le squares +and that's not for any function it's + + align:start position:0% +and that's not for any function it's + + + align:start position:0% +and that's not for any function it's +when we're trying to use the fact that + + align:start position:0% +when we're trying to use the fact that + + + align:start position:0% +when we're trying to use the fact that +there is this linear dependence on the + + align:start position:0% +there is this linear dependence on the + + + align:start position:0% +there is this linear dependence on the +XIs and this is essentially going to + + align:start position:0% +XIs and this is essentially going to + + + align:start position:0% +XIs and this is essentially going to +tell us well you know you can use lead + + align:start position:0% +tell us well you know you can use lead + + + align:start position:0% +tell us well you know you can use lead +squares for linear regression here you + + align:start position:0% +squares for linear regression here you + + + align:start position:0% +squares for linear regression here you +can use Le squares but locally and you + + align:start position:0% +can use Le squares but locally and you + + + align:start position:0% +can use Le squares but locally and you +have to iterate okay and uh this last + + align:start position:0% +have to iterate okay and uh this last + + + align:start position:0% +have to iterate okay and uh this last +part is essentially a trick by + + align:start position:0% +part is essentially a trick by + + + align:start position:0% +part is essentially a trick by +statisticians to be able to solve the + + align:start position:0% +statisticians to be able to solve the + + + align:start position:0% +statisticians to be able to solve the +Newton rafson updates without actually + + align:start position:0% +Newton rafson updates without actually + + + align:start position:0% +Newton rafson updates without actually +uh having a dedicated software for this + + align:start position:0% +uh having a dedicated software for this + + + align:start position:0% +uh having a dedicated software for this +but just being able to reuse some Le + + align:start position:0% +but just being able to reuse some Le + + + align:start position:0% +but just being able to reuse some Le +squares software + + align:start position:0% +squares software + + + align:start position:0% +squares software +okay so you know uh we've talked about + + align:start position:0% +okay so you know uh we've talked about + + + align:start position:0% +okay so you know uh we've talked about +this many times I just want to make sure + + align:start position:0% +this many times I just want to make sure + + + align:start position:0% +this many times I just want to make sure +that uh we're all on the same page here + + align:start position:0% +that uh we're all on the same page here + + + align:start position:0% +that uh we're all on the same page here +uh we have a function f we're going to + + align:start position:0% +uh we have a function f we're going to + + + align:start position:0% +uh we have a function f we're going to +assume that it has two derivatives and + + align:start position:0% +assume that it has two derivatives and + + + align:start position:0% +assume that it has two derivatives and +it's a function from RM to R so its + + align:start position:0% +it's a function from RM to R so its + + + align:start position:0% +it's a function from RM to R so its +first derivative is called gradient + + align:start position:0% +first derivative is called gradient + + + align:start position:0% +first derivative is called gradient +that's just the vector that collects all + + align:start position:0% +that's just the vector that collects all + + + align:start position:0% +that's just the vector that collects all +the partial derivatives with respect to + + align:start position:0% +the partial derivatives with respect to + + + align:start position:0% +the partial derivatives with respect to +each of the coordinates it's Dimension M + + align:start position:0% +each of the coordinates it's Dimension M + + + align:start position:0% +each of the coordinates it's Dimension M +of course and the second derivative is + + align:start position:0% +of course and the second derivative is + + + align:start position:0% +of course and the second derivative is +an M by m matx is called the hen and on + + align:start position:0% +an M by m matx is called the hen and on + + + align:start position:0% +an M by m matx is called the hen and on +the i j on the I row and jth column you + + align:start position:0% +the i j on the I row and jth column you + + + align:start position:0% +the i j on the I row and jth column you +see the second partial derivative with + + align:start position:0% +see the second partial derivative with + + + align:start position:0% +see the second partial derivative with +respect to the I component and the J + + align:start position:0% +respect to the I component and the J + + + align:start position:0% +respect to the I component and the J +component okay we've seen that several + + align:start position:0% +component okay we've seen that several + + + align:start position:0% +component okay we've seen that several +times this is just multivariable + + align:start position:0% +times this is just multivariable + + + align:start position:0% +times this is just multivariable +calculus uh but uh really the point here + + align:start position:0% +calculus uh but uh really the point here + + + align:start position:0% +calculus uh but uh really the point here +is to uh maybe the notation is slightly + + align:start position:0% +is to uh maybe the notation is slightly + + + align:start position:0% +is to uh maybe the notation is slightly +different because I want to keep track + + align:start position:0% +different because I want to keep track + + + align:start position:0% +different because I want to keep track +of f so when I write gradient I write + + align:start position:0% +of f so when I write gradient I write + + + align:start position:0% +of f so when I write gradient I write +nabla sub F and and when I write hen I + + align:start position:0% +nabla sub F and and when I write hen I + + + align:start position:0% +nabla sub F and and when I write hen I +write Naas sub H sub + + align:start position:0% +write Naas sub H sub + + + align:start position:0% +write Naas sub H sub +F and if as I said if f is strictly + + align:start position:0% +F and if as I said if f is strictly + + + align:start position:0% +F and if as I said if f is strictly +concave then HF ofx is negative definite + + align:start position:0% +concave then HF ofx is negative definite + + + align:start position:0% +concave then HF ofx is negative definite +what it means is that if I take + + align:start position:0% +what it means is that if I take + + + align:start position:0% +what it means is that if I take +any + + align:start position:0% +any + + + align:start position:0% +any +X in + + align:start position:0% +X in + + + align:start position:0% +X in +RM then X transpose + + align:start position:0% +RM then X transpose + + + align:start position:0% +RM then X transpose +HF uh well that's for any + + align:start position:0% +HF uh well that's for any + + + align:start position:0% +HF uh well that's for any +x0 X this is actually strictly + + align:start position:0% +x0 X this is actually strictly + + + align:start position:0% +x0 X this is actually strictly +negative that's what it means to be + + align:start position:0% +negative that's what it means to be + + + align:start position:0% +negative that's what it means to be +negative definite okay so every time I + + align:start position:0% +negative definite okay so every time I + + + align:start position:0% +negative definite okay so every time I +do X transpose so if I so this is like a + + align:start position:0% +do X transpose so if I so this is like a + + + align:start position:0% +do X transpose so if I so this is like a +quadratic form and I want it to be + + align:start position:0% +quadratic form and I want it to be + + + align:start position:0% +quadratic form and I want it to be +negative for all values of x0 and X both + + align:start position:0% +negative for all values of x0 and X both + + + align:start position:0% +negative for all values of x0 and X both +of them that's very strong + + align:start position:0% +of them that's very strong + + + align:start position:0% +of them that's very strong +clearly uh but for us actually this is + + align:start position:0% +clearly uh but for us actually this is + + + align:start position:0% +clearly uh but for us actually this is +what happens just because of the + + align:start position:0% +what happens just because of the + + + align:start position:0% +what happens just because of the +properties of + + align:start position:0% +properties of + + + align:start position:0% +properties of +B uh well at least the fact that it's + + align:start position:0% +B uh well at least the fact that it's + + + align:start position:0% +B uh well at least the fact that it's +negative less than or equal to if I want + + align:start position:0% +negative less than or equal to if I want + + + align:start position:0% +negative less than or equal to if I want +it to be strictly less I need some + + align:start position:0% +it to be strictly less I need some + + + align:start position:0% +it to be strictly less I need some +properties on + + align:start position:0% +properties on + + + align:start position:0% +properties on +X and then I will call the H map the + + align:start position:0% +X and then I will call the H map the + + + align:start position:0% +X and then I will call the H map the +function that Maps X to this Matrix + + align:start position:0% +function that Maps X to this Matrix + + + align:start position:0% +function that Maps X to this Matrix +HF of X okay so that's just a second + + align:start position:0% +HF of X okay so that's just a second + + + align:start position:0% +HF of X okay so that's just a second +derivative at X + + align:start position:0% + + + + align:start position:0% + +yeah where do I say + + align:start position:0% +yeah where do I say + + + align:start position:0% +yeah where do I say +smooth oh yeah uh I mean you know you + + align:start position:0% +smooth oh yeah uh I mean you know you + + + align:start position:0% +smooth oh yeah uh I mean you know you +need to be able to apply Schwarz Lama + + align:start position:0% +need to be able to apply Schwarz Lama + + + align:start position:0% +need to be able to apply Schwarz Lama +let's say two continuous derivatives + + align:start position:0% +let's say two continuous derivatives + + + align:start position:0% +let's say two continuous derivatives +that's + + align:start position:0% + + + + align:start position:0% + +smooth no that's fine + + align:start position:0% + + + + align:start position:0% + +okay so how does the Newton rafon uh + + align:start position:0% +okay so how does the Newton rafon uh + + + align:start position:0% +okay so how does the Newton rafon uh +method work well what it does is that it + + align:start position:0% +method work well what it does is that it + + + align:start position:0% +method work well what it does is that it +forms a quadratic approximation to your + + align:start position:0% +forms a quadratic approximation to your + + + align:start position:0% +forms a quadratic approximation to your +function and that's the one it optimizes + + align:start position:0% +function and that's the one it optimizes + + + align:start position:0% +function and that's the one it optimizes +at every single point okay and the + + align:start position:0% +at every single point okay and the + + + align:start position:0% +at every single point okay and the +reason is because we have a close form + + align:start position:0% +reason is because we have a close form + + + align:start position:0% +reason is because we have a close form +solution to Def finding the minimum of a + + align:start position:0% +solution to Def finding the minimum of a + + + align:start position:0% +solution to Def finding the minimum of a +quadratic function so if I give you a + + align:start position:0% +quadratic function so if I give you a + + + align:start position:0% +quadratic function so if I give you a +function that's of the form ax2 plus b x + + align:start position:0% +function that's of the form ax2 plus b x + + + align:start position:0% +function that's of the form ax2 plus b x +plus C you know exactly a close form for + + align:start position:0% +plus C you know exactly a close form for + + + align:start position:0% +plus C you know exactly a close form for +its minimum and but if I give you any + + align:start position:0% +its minimum and but if I give you any + + + align:start position:0% +its minimum and but if I give you any +function or let's say yeah so here it's + + align:start position:0% +function or let's say yeah so here it's + + + align:start position:0% +function or let's say yeah so here it's +all about maximum I'm sorry I'm going to + + align:start position:0% +all about maximum I'm sorry I'm going to + + + align:start position:0% +all about maximum I'm sorry I'm going to +try to if you're confused with me using + + align:start position:0% +try to if you're confused with me using + + + align:start position:0% +try to if you're confused with me using +the word minimum just assume that it was + + align:start position:0% +the word minimum just assume that it was + + + align:start position:0% +the word minimum just assume that it was +the word maximum um so this is how it + + align:start position:0% +the word maximum um so this is how it + + + align:start position:0% +the word maximum um so this is how it +works okay if I give + + align:start position:0% +works okay if I give + + + align:start position:0% +works okay if I give +you a function which is concave and + + align:start position:0% +you a function which is concave and + + + align:start position:0% +you a function which is concave and +that's quadratic okay so it's going to + + align:start position:0% +that's quadratic okay so it's going to + + + align:start position:0% +that's quadratic okay so it's going to +look like + + align:start position:0% + + + + align:start position:0% + +this all right so that's of the form ax2 + + align:start position:0% +this all right so that's of the form ax2 + + + align:start position:0% +this all right so that's of the form ax2 +where a is negative of course plus BX + + align:start position:0% +where a is negative of course plus BX + + + align:start position:0% +where a is negative of course plus BX +plus C then you know you can solve your + + align:start position:0% +plus C then you know you can solve your + + + align:start position:0% +plus C then you know you can solve your +uh whatever you can take the derivative + + align:start position:0% +uh whatever you can take the derivative + + + align:start position:0% +uh whatever you can take the derivative +of this guy set it equal to zero and you + + align:start position:0% +of this guy set it equal to zero and you + + + align:start position:0% +of this guy set it equal to zero and you +will have an exact equation into what + + align:start position:0% +will have an exact equation into what + + + align:start position:0% +will have an exact equation into what +the value of x is that realizes this + + align:start position:0% +the value of x is that realizes this + + + align:start position:0% +the value of x is that realizes this +maximum if I give you any function + + align:start position:0% +maximum if I give you any function + + + align:start position:0% +maximum if I give you any function +that's + + align:start position:0% + + + + align:start position:0% + +concave that's not clear right I mean + + align:start position:0% +concave that's not clear right I mean + + + align:start position:0% +concave that's not clear right I mean +you know if I tell you the function that + + align:start position:0% +you know if I tell you the function that + + + align:start position:0% +you know if I tell you the function that +we have here is of the form ax minus B + + align:start position:0% +we have here is of the form ax minus B + + + align:start position:0% +we have here is of the form ax minus B +of X right then I'm just going to have + + align:start position:0% +of X right then I'm just going to have + + + align:start position:0% +of X right then I'm just going to have +something that inverts uh B Prime but + + align:start position:0% +something that inverts uh B Prime but + + + align:start position:0% +something that inverts uh B Prime but +you know how do I do it exactly it's not + + align:start position:0% +you know how do I do it exactly it's not + + + align:start position:0% +you know how do I do it exactly it's not +clear and so what we do is we do a + + align:start position:0% +clear and so what we do is we do a + + + align:start position:0% +clear and so what we do is we do a +quadratic approximation which should be + + align:start position:0% +quadratic approximation which should be + + + align:start position:0% +quadratic approximation which should be +true approximately everywhere right so + + align:start position:0% +true approximately everywhere right so + + + align:start position:0% +true approximately everywhere right so +if I'm at this point here I'm going to + + align:start position:0% +if I'm at this point here I'm going to + + + align:start position:0% +if I'm at this point here I'm going to +say oh I'm close to being that + + align:start position:0% +say oh I'm close to being that + + + align:start position:0% +say oh I'm close to being that +function and if I'm at this point here + + align:start position:0% +function and if I'm at this point here + + + align:start position:0% +function and if I'm at this point here +I'm going to be close to being that + + align:start position:0% +I'm going to be close to being that + + + align:start position:0% +I'm going to be close to being that +function and for this functions I can + + align:start position:0% +function and for this functions I can + + + align:start position:0% +function and for this functions I can +actually optimize and so if I'm not + + align:start position:0% +actually optimize and so if I'm not + + + align:start position:0% +actually optimize and so if I'm not +moving too far from one to the other I + + align:start position:0% +moving too far from one to the other I + + + align:start position:0% +moving too far from one to the other I +should actually get something so here's + + align:start position:0% +should actually get something so here's + + + align:start position:0% +should actually get something so here's +how the quadratic approximation works + + align:start position:0% +how the quadratic approximation works + + + align:start position:0% +how the quadratic approximation works +I'm going to write the second + + align:start position:0% + + + + align:start position:0% + +order tailor expansion + + align:start position:0% + + + + align:start position:0% + +okay and so that's just going to be my + + align:start position:0% +okay and so that's just going to be my + + + align:start position:0% +okay and so that's just going to be my +quadratic approximation is going to say + + align:start position:0% +quadratic approximation is going to say + + + align:start position:0% +quadratic approximation is going to say +oh F ofx when X is close to some point + + align:start position:0% +oh F ofx when X is close to some point + + + align:start position:0% +oh F ofx when X is close to some point +x0 is going to be close to F of x0 plus + + align:start position:0% +x0 is going to be close to F of x0 plus + + + align:start position:0% +x0 is going to be close to F of x0 plus +the gradient of F at x0 transpose x - + + align:start position:0% +the gradient of F at x0 transpose x - + + + align:start position:0% +the gradient of F at x0 transpose x - +x0 and then I'm going to have plus 12 x + + align:start position:0% +x0 and then I'm going to have plus 12 x + + + align:start position:0% +x0 and then I'm going to have plus 12 x +- x0 transpose HF at x0 x - x transpose + + align:start position:0% +- x0 transpose HF at x0 x - x transpose + + + align:start position:0% +- x0 transpose HF at x0 x - x transpose +right x- x0 so that's just my second + + align:start position:0% +right x- x0 so that's just my second + + + align:start position:0% +right x- x0 so that's just my second +order tailor expansion multivariate one + + align:start position:0% +order tailor expansion multivariate one + + + align:start position:0% +order tailor expansion multivariate one +and that's let's say if x0 is this + + align:start position:0% + + + + align:start position:0% + +guy now what I'm going to do is say okay + + align:start position:0% +guy now what I'm going to do is say okay + + + align:start position:0% +guy now what I'm going to do is say okay +if I wanted to set this the derivative + + align:start position:0% +if I wanted to set this the derivative + + + align:start position:0% +if I wanted to set this the derivative +of this guy equal to zero I would just + + align:start position:0% +of this guy equal to zero I would just + + + align:start position:0% +of this guy equal to zero I would just +have to solve well you know frime of x + + align:start position:0% +have to solve well you know frime of x + + + align:start position:0% +have to solve well you know frime of x +equals z meaning that X has to be F + + align:start position:0% +equals z meaning that X has to be F + + + align:start position:0% +equals z meaning that X has to be F +Prime inverse of zero and really apart + + align:start position:0% +Prime inverse of zero and really apart + + + align:start position:0% +Prime inverse of zero and really apart +from like being some notation + + align:start position:0% +from like being some notation + + + align:start position:0% +from like being some notation +manipulations this is really not helping + + align:start position:0% +manipulations this is really not helping + + + align:start position:0% +manipulations this is really not helping +me okay because I don't know what fime + + align:start position:0% +me okay because I don't know what fime + + + align:start position:0% +me okay because I don't know what fime +inverse of zero is in many instances + + align:start position:0% +inverse of zero is in many instances + + + align:start position:0% +inverse of zero is in many instances +however if F has a very specific form + + align:start position:0% +however if F has a very specific form + + + align:start position:0% +however if F has a very specific form +which is something that depends on X in + + align:start position:0% +which is something that depends on X in + + + align:start position:0% +which is something that depends on X in +a very specific way there's just a + + align:start position:0% +a very specific way there's just a + + + align:start position:0% +a very specific way there's just a +linear term and then a quadratic term + + align:start position:0% +linear term and then a quadratic term + + + align:start position:0% +linear term and then a quadratic term +then I can actually do something right + + align:start position:0% +then I can actually do something right + + + align:start position:0% +then I can actually do something right +so let's forget about this approach and + + align:start position:0% +so let's forget about this approach and + + + align:start position:0% +so let's forget about this approach and +rather than minimizing F let's just + + align:start position:0% +rather than minimizing F let's just + + + align:start position:0% +rather than minimizing F let's just +minimize the right hand + + align:start position:0% +minimize the right hand + + + align:start position:0% +minimize the right hand +side okay + + align:start position:0% +side okay + + + align:start position:0% +side okay +so sorry maximize so + + align:start position:0% + + + + align:start position:0% + +maximize the right hand + + align:start position:0% +maximize the right hand + + + align:start position:0% +maximize the right hand +side and so how do I get this well I + + align:start position:0% +side and so how do I get this well I + + + align:start position:0% +side and so how do I get this well I +just set the + + align:start position:0% +just set the + + + align:start position:0% +just set the +gradient equal to zero so what is the + + align:start position:0% +gradient equal to zero so what is the + + + align:start position:0% +gradient equal to zero so what is the +gradient the first term does not uh + + align:start position:0% +gradient the first term does not uh + + + align:start position:0% +gradient the first term does not uh +depend on X okay so that means that this + + align:start position:0% +depend on X okay so that means that this + + + align:start position:0% +depend on X okay so that means that this +is going to be + + align:start position:0% +is going to be + + + align:start position:0% +is going to be +zero plus what is the gradient of this + + align:start position:0% +zero plus what is the gradient of this + + + align:start position:0% +zero plus what is the gradient of this +thing of uh the gradient of F at x0 + + align:start position:0% +thing of uh the gradient of F at x0 + + + align:start position:0% +thing of uh the gradient of F at x0 +transpose x - x0 what is the gradient of + + align:start position:0% +transpose x - x0 what is the gradient of + + + align:start position:0% +transpose x - x0 what is the gradient of +this + + align:start position:0% + + + + align:start position:0% + +guy so I have a function of the Form B + + align:start position:0% +guy so I have a function of the Form B + + + align:start position:0% +guy so I have a function of the Form B +transpose x what is the gradient of this + + align:start position:0% +transpose x what is the gradient of this + + + align:start position:0% +transpose x what is the gradient of this +thing I'm + + align:start position:0% + + + + align:start position:0% + +sorry I'm writing everything into column + + align:start position:0% +sorry I'm writing everything into column + + + align:start position:0% +sorry I'm writing everything into column +form right so it's just B okay so here + + align:start position:0% +form right so it's just B okay so here + + + align:start position:0% +form right so it's just B okay so here +what is B well it's + + align:start position:0% +what is B well it's + + + align:start position:0% +what is B well it's +gradient of F at + + align:start position:0% + + + + align:start position:0% + +x0 okay on this term here gradient of F + + align:start position:0% +x0 okay on this term here gradient of F + + + align:start position:0% +x0 okay on this term here gradient of F +at x0 transpose x0 is just a constant + + align:start position:0% +at x0 transpose x0 is just a constant + + + align:start position:0% +at x0 transpose x0 is just a constant +this thing is going away as well and + + align:start position:0% +this thing is going away as well and + + + align:start position:0% +this thing is going away as well and +then I'm looking at the derivative of + + align:start position:0% +then I'm looking at the derivative of + + + align:start position:0% +then I'm looking at the derivative of +this guy here and this is like a + + align:start position:0% +this guy here and this is like a + + + align:start position:0% +this guy here and this is like a +quadratic term it's like H * x - x0 2 so + + align:start position:0% +quadratic term it's like H * x - x0 2 so + + + align:start position:0% +quadratic term it's like H * x - x0 2 so +when I'm going to take the derivative + + align:start position:0% +when I'm going to take the derivative + + + align:start position:0% +when I'm going to take the derivative +I'm going to have a factor two that's + + align:start position:0% +I'm going to have a factor two that's + + + align:start position:0% +I'm going to have a factor two that's +going to pop out and cancel this one + + align:start position:0% +going to pop out and cancel this one + + + align:start position:0% +going to pop out and cancel this one +half and then I'm going to be left only + + align:start position:0% +half and then I'm going to be left only + + + align:start position:0% +half and then I'm going to be left only +with this part times this part + + align:start position:0% +with this part times this part + + + align:start position:0% +with this part times this part +okay so that's + + align:start position:0% +okay so that's + + + align:start position:0% +okay so that's +plus + + align:start position:0% +plus + + + align:start position:0% +plus +HF x - + + align:start position:0% +HF x - + + + align:start position:0% +HF x - +x0 okay so that's just the gradient and + + align:start position:0% +x0 okay so that's just the gradient and + + + align:start position:0% +x0 okay so that's just the gradient and +I want it to be equal to zero so I'm + + align:start position:0% +I want it to be equal to zero so I'm + + + align:start position:0% +I want it to be equal to zero so I'm +just going to solve this equal to + + align:start position:0% +just going to solve this equal to + + + align:start position:0% +just going to solve this equal to +zero okay so that means that if I want + + align:start position:0% +zero okay so that means that if I want + + + align:start position:0% +zero okay so that means that if I want +to find the minimum this is just going + + align:start position:0% +to find the minimum this is just going + + + align:start position:0% +to find the minimum this is just going +to be the X star that satisfies this so + + align:start position:0% +to be the X star that satisfies this so + + + align:start position:0% +to be the X star that satisfies this so +that's actually equivalent to + + align:start position:0% +that's actually equivalent to + + + align:start position:0% +that's actually equivalent to +HF * X + + align:start position:0% +HF * X + + + align:start position:0% +HF * X +star is equal + + align:start position:0% +star is equal + + + align:start position:0% +star is equal +to + + align:start position:0% +to + + + align:start position:0% +to +um + + align:start position:0% +um + + + align:start position:0% +um +HF + + align:start position:0% +HF + + + align:start position:0% +HF +x0 minus gradient F at + + align:start position:0% + + + + align:start position:0% + +x0 now this is a much easier thing to + + align:start position:0% +x0 now this is a much easier thing to + + + align:start position:0% +x0 now this is a much easier thing to +solve what is + + align:start position:0% + + + + align:start position:0% + +this this is just a system of linear + + align:start position:0% +this this is just a system of linear + + + align:start position:0% +this this is just a system of linear +equations + + align:start position:0% +equations + + + align:start position:0% +equations +right I just need to find the X star so + + align:start position:0% +right I just need to find the X star so + + + align:start position:0% +right I just need to find the X star so +that when I premultiply it by a matrix I + + align:start position:0% +that when I premultiply it by a matrix I + + + align:start position:0% +that when I premultiply it by a matrix I +get this Vector on the right hand side + + align:start position:0% +get this Vector on the right hand side + + + align:start position:0% +get this Vector on the right hand side +this is just something of the form ax + + align:start position:0% +this is just something of the form ax + + + align:start position:0% +this is just something of the form ax +equals B and I have many ways I can do + + align:start position:0% +equals B and I have many ways I can do + + + align:start position:0% +equals B and I have many ways I can do +this I could do gaussin elimination or I + + align:start position:0% +this I could do gaussin elimination or I + + + align:start position:0% +this I could do gaussin elimination or I +could use you know spillman's fast + + align:start position:0% +could use you know spillman's fast + + + align:start position:0% +could use you know spillman's fast +lassan solvers if I had some particular + + align:start position:0% +lassan solvers if I had some particular + + + align:start position:0% +lassan solvers if I had some particular +properties of H I mean there's huge + + align:start position:0% +properties of H I mean there's huge + + + align:start position:0% +properties of H I mean there's huge +activity in terms of how to solve those + + align:start position:0% +activity in terms of how to solve those + + + align:start position:0% +activity in terms of how to solve those +systems but let's say I don't I have + + align:start position:0% +systems but let's say I don't I have + + + align:start position:0% +systems but let's say I don't I have +some time it's not a huge problem + + align:start position:0% +some time it's not a huge problem + + + align:start position:0% +some time it's not a huge problem +I can actually just use linear algebra + + align:start position:0% +I can actually just use linear algebra + + + align:start position:0% +I can actually just use linear algebra +and linear algebra just tells me that + + align:start position:0% +and linear algebra just tells me that + + + align:start position:0% +and linear algebra just tells me that +xar is equal to HF + + align:start position:0% +xar is equal to HF + + + align:start position:0% +xar is equal to HF +inverse times this + + align:start position:0% + + + + align:start position:0% + +guy which those two guys are going to + + align:start position:0% +guy which those two guys are going to + + + align:start position:0% +guy which those two guys are going to +cancel so this actually equal to x0 + + align:start position:0% +cancel so this actually equal to x0 + + + align:start position:0% +cancel so this actually equal to x0 +minus HF inverse gradient F at + + align:start position:0% +minus HF inverse gradient F at + + + align:start position:0% +minus HF inverse gradient F at +x0 and that's just what's called a + + align:start position:0% +x0 and that's just what's called a + + + align:start position:0% +x0 and that's just what's called a +Newton iterations I started at some + + align:start position:0% +Newton iterations I started at some + + + align:start position:0% +Newton iterations I started at some +x0 I'm at some x0 where I make my + + align:start position:0% +x0 I'm at some x0 where I make my + + + align:start position:0% +x0 I'm at some x0 where I make my +approximation and it's telling me if + + align:start position:0% +approximation and it's telling me if + + + align:start position:0% +approximation and it's telling me if +starting from this x zero I wanted to + + align:start position:0% +starting from this x zero I wanted to + + + align:start position:0% +starting from this x zero I wanted to +fully optimize the quadratic + + align:start position:0% +fully optimize the quadratic + + + align:start position:0% +fully optimize the quadratic +approximation I would just have to take + + align:start position:0% +approximation I would just have to take + + + align:start position:0% +approximation I would just have to take +the X star that's this guy and then I + + align:start position:0% +the X star that's this guy and then I + + + align:start position:0% +the X star that's this guy and then I +could just use this guy as my X zero and + + align:start position:0% +could just use this guy as my X zero and + + + align:start position:0% +could just use this guy as my X zero and +do it again and again and again and + + align:start position:0% +do it again and again and again and + + + align:start position:0% +do it again and again and again and +again and those are called Newton + + align:start position:0% +again and those are called Newton + + + align:start position:0% +again and those are called Newton +iterations and they're basically the + + align:start position:0% +iterations and they're basically the + + + align:start position:0% +iterations and they're basically the +working hor the Workhorse of of uh you + + align:start position:0% +working hor the Workhorse of of uh you + + + align:start position:0% +working hor the Workhorse of of uh you +know interior Point methods for example + + align:start position:0% +know interior Point methods for example + + + align:start position:0% +know interior Point methods for example +a lot of optimization algorithms and + + align:start position:0% +a lot of optimization algorithms and + + + align:start position:0% +a lot of optimization algorithms and +that's what you can you see here xar is + + align:start position:0% +that's what you can you see here xar is + + + align:start position:0% +that's what you can you see here xar is +equal to x0 minus the inverse hen times + + align:start position:0% +equal to x0 minus the inverse hen times + + + align:start position:0% +equal to x0 minus the inverse hen times +the + + align:start position:0% +the + + + align:start position:0% +the +gradient we briefly mentioned gradient + + align:start position:0% +gradient we briefly mentioned gradient + + + align:start position:0% +gradient we briefly mentioned gradient +descent we briefly mention gradient + + align:start position:0% +descent we briefly mention gradient + + + align:start position:0% +descent we briefly mention gradient +descent right at some point to optimize + + align:start position:0% +descent right at some point to optimize + + + align:start position:0% +descent right at some point to optimize +a convex function right and if I wanted + + align:start position:0% +a convex function right and if I wanted + + + align:start position:0% +a convex function right and if I wanted +to use gradient + + align:start position:0% +to use gradient + + + align:start position:0% +to use gradient +descent + + align:start position:0% +descent + + + align:start position:0% +descent +again H is a matrix but if I wanted to + + align:start position:0% +again H is a matrix but if I wanted to + + + align:start position:0% +again H is a matrix but if I wanted to +think of H as being a scalar would it be + + align:start position:0% +think of H as being a scalar would it be + + + align:start position:0% +think of H as being a scalar would it be +a positive or negative number + + align:start position:0% + + + + align:start position:0% + +yeah + + align:start position:0% + + + + align:start position:0% + +why yeah so that would be this so I want + + align:start position:0% +why yeah so that would be this so I want + + + align:start position:0% +why yeah so that would be this so I want +to move against the gradient to do what + + align:start position:0% +to move against the gradient to do what + + + align:start position:0% +to move against the gradient to do what +to minimize but I'm maximizing here + + align:start position:0% +to minimize but I'm maximizing here + + + align:start position:0% +to minimize but I'm maximizing here +right everything is maximized right so I + + align:start position:0% +right everything is maximized right so I + + + align:start position:0% +right everything is maximized right so I +know that H is actually negative + + align:start position:0% +know that H is actually negative + + + align:start position:0% +know that H is actually negative +definite so it's a negative number okay + + align:start position:0% +definite so it's a negative number okay + + + align:start position:0% +definite so it's a negative number okay +so that's you're making the same uh you + + align:start position:0% +so that's you're making the same uh you + + + align:start position:0% +so that's you're making the same uh you +have the same confusion as I do we're + + align:start position:0% +have the same confusion as I do we're + + + align:start position:0% +have the same confusion as I do we're +maximizing a concave function here so H + + align:start position:0% +maximizing a concave function here so H + + + align:start position:0% +maximizing a concave function here so H +is negative so this is something of the + + align:start position:0% +is negative so this is something of the + + + align:start position:0% +is negative so this is something of the +form + + align:start position:0% +form + + + align:start position:0% +form +x0 plus something times the + + align:start position:0% +x0 plus something times the + + + align:start position:0% +x0 plus something times the +gradient and this is what your gradient + + align:start position:0% +gradient and this is what your gradient + + + align:start position:0% +gradient and this is what your gradient +Ascent rather than descent would look + + align:start position:0% +Ascent rather than descent would look + + + align:start position:0% +Ascent rather than descent would look +like and all it's saying Newton is + + align:start position:0% +like and all it's saying Newton is + + + align:start position:0% +like and all it's saying Newton is +telling you don't take the gradient for + + align:start position:0% +telling you don't take the gradient for + + + align:start position:0% +telling you don't take the gradient for +granted as a direction in which you want + + align:start position:0% +granted as a direction in which you want + + + align:start position:0% +granted as a direction in which you want +to go it says do a slight change of + + align:start position:0% +to go it says do a slight change of + + + align:start position:0% +to go it says do a slight change of +coordinates before you do this according + + align:start position:0% +coordinates before you do this according + + + align:start position:0% +coordinates before you do this according +to what you're + + align:start position:0% +to what you're + + + align:start position:0% +to what you're +hashen looks + + align:start position:0% +hashen looks + + + align:start position:0% +hashen looks +like all right and that's what uh those + + align:start position:0% +like all right and that's what uh those + + + align:start position:0% +like all right and that's what uh those +are called second order methods that + + align:start position:0% +are called second order methods that + + + align:start position:0% +are called second order methods that +require knowing what the hashen is but + + align:start position:0% +require knowing what the hashen is but + + + align:start position:0% +require knowing what the hashen is but +uh those are actually much more powerful + + align:start position:0% +uh those are actually much more powerful + + + align:start position:0% +uh those are actually much more powerful +than the gradient descent because + + align:start position:0% +than the gradient descent because + + + align:start position:0% +than the gradient descent because +they're using all of the local geometry + + align:start position:0% +they're using all of the local geometry + + + align:start position:0% +they're using all of the local geometry +of the problem all of the local geometry + + align:start position:0% +of the problem all of the local geometry + + + align:start position:0% +of the problem all of the local geometry +of your function is completely encoded + + align:start position:0% +of your function is completely encoded + + + align:start position:0% +of your function is completely encoded +in this hashen and in particular it + + align:start position:0% +in this hashen and in particular it + + + align:start position:0% +in this hashen and in particular it +implies that it tells you where to + + align:start position:0% +implies that it tells you where to + + + align:start position:0% +implies that it tells you where to +switch and not uh go slower in some + + align:start position:0% +switch and not uh go slower in some + + + align:start position:0% +switch and not uh go slower in some +places or go faster in other places now + + align:start position:0% +places or go faster in other places now + + + align:start position:0% +places or go faster in other places now +this in practice for say say modern + + align:start position:0% +this in practice for say say modern + + + align:start position:0% +this in practice for say say modern +large scale machine learning problems + + align:start position:0% +large scale machine learning problems + + + align:start position:0% +large scale machine learning problems +inverting this Matrix H is extremely + + align:start position:0% +inverting this Matrix H is extremely + + + align:start position:0% +inverting this Matrix H is extremely +painful it's it takes too much time the + + align:start position:0% +painful it's it takes too much time the + + + align:start position:0% +painful it's it takes too much time the +Matrix is too big and computers cannot + + align:start position:0% +Matrix is too big and computers cannot + + + align:start position:0% +Matrix is too big and computers cannot +do it and people resort to what's called + + align:start position:0% +do it and people resort to what's called + + + align:start position:0% +do it and people resort to what's called +uh pseudo uh Newton methods which + + align:start position:0% +uh pseudo uh Newton methods which + + + align:start position:0% +uh pseudo uh Newton methods which +essentially try to emulate what this guy + + align:start position:0% +essentially try to emulate what this guy + + + align:start position:0% +essentially try to emulate what this guy +is and there's many ways you can do this + + align:start position:0% +is and there's many ways you can do this + + + align:start position:0% +is and there's many ways you can do this +some of them is by using gradients that + + align:start position:0% +some of them is by using gradients that + + + align:start position:0% +some of them is by using gradients that +you've collected in the + + align:start position:0% +you've collected in the + + + align:start position:0% +you've collected in the +past uh some of them is using the fact + + align:start position:0% +past uh some of them is using the fact + + + align:start position:0% +past uh some of them is using the fact +that uh uh just say well let's just + + align:start position:0% +that uh uh just say well let's just + + + align:start position:0% +that uh uh just say well let's just +pretend is diagonal uh just there's a + + align:start position:0% +pretend is diagonal uh just there's a + + + align:start position:0% +pretend is diagonal uh just there's a +lot of things you can do to just play + + align:start position:0% +lot of things you can do to just play + + + align:start position:0% +lot of things you can do to just play +around this and not actually have to + + align:start position:0% +around this and not actually have to + + + align:start position:0% +around this and not actually have to +invert this Matrix + + align:start position:0% +invert this Matrix + + + align:start position:0% +invert this Matrix +okay so once you have this you started + + align:start position:0% +okay so once you have this you started + + + align:start position:0% +okay so once you have this you started +from Edge zero it tells you which H star + + align:start position:0% +from Edge zero it tells you which H star + + + align:start position:0% +from Edge zero it tells you which H star +you can get uh as the maximizer of the + + align:start position:0% +you can get uh as the maximizer of the + + + align:start position:0% +you can get uh as the maximizer of the +local quadratic approximation to your + + align:start position:0% +local quadratic approximation to your + + + align:start position:0% +local quadratic approximation to your +function you can actually just iterate + + align:start position:0% +function you can actually just iterate + + + align:start position:0% +function you can actually just iterate +that all right so you start at some X + + align:start position:0% +that all right so you start at some X + + + align:start position:0% +that all right so you start at some X +zero somewhere and then once you get to + + align:start position:0% +zero somewhere and then once you get to + + + align:start position:0% +zero somewhere and then once you get to +some XK you just do the Iration we just + + align:start position:0% +some XK you just do the Iration we just + + + align:start position:0% +some XK you just do the Iration we just +described which is just find k + 1 which + + align:start position:0% +described which is just find k + 1 which + + + align:start position:0% +described which is just find k + 1 which +is the maximizer of the local quadratic + + align:start position:0% +is the maximizer of the local quadratic + + + align:start position:0% +is the maximizer of the local quadratic +approximation to your function at XK and + + align:start position:0% +approximation to your function at XK and + + + align:start position:0% +approximation to your function at XK and +repeat until + + align:start position:0% +repeat until + + + align:start position:0% +repeat until +convergence okay so if this was an + + align:start position:0% +convergence okay so if this was an + + + align:start position:0% +convergence okay so if this was an +optimization class we would prove that + + align:start position:0% +optimization class we would prove that + + + align:start position:0% +optimization class we would prove that +convergence actually eventually happens + + align:start position:0% +convergence actually eventually happens + + + align:start position:0% +convergence actually eventually happens +for a uh strictly concave function uh + + align:start position:0% +for a uh strictly concave function uh + + + align:start position:0% +for a uh strictly concave function uh +this is a stas class you're just going + + align:start position:0% +this is a stas class you're just going + + + align:start position:0% +this is a stas class you're just going +to have to trust me that this is the + + align:start position:0% +to have to trust me that this is the + + + align:start position:0% +to have to trust me that this is the +case and it's globally convergent + + align:start position:0% +case and it's globally convergent + + + align:start position:0% +case and it's globally convergent +meaning that you can start wherever you + + align:start position:0% +meaning that you can start wherever you + + + align:start position:0% +meaning that you can start wherever you +want and uh and it's going to work and + + align:start position:0% +want and uh and it's going to work and + + + align:start position:0% +want and uh and it's going to work and +uh uh for under minor conditions on F in + + align:start position:0% +uh uh for under minor conditions on F in + + + align:start position:0% +uh uh for under minor conditions on F in +particular those conditions are + + align:start position:0% +particular those conditions are + + + align:start position:0% +particular those conditions are +satisfied for the uh log likelihood + + align:start position:0% +satisfied for the uh log likelihood + + + align:start position:0% +satisfied for the uh log likelihood +functions we have in mind okay and it + + align:start position:0% +functions we have in mind okay and it + + + align:start position:0% +functions we have in mind okay and it +converges at an extremely fast rate + + align:start position:0% +converges at an extremely fast rate + + + align:start position:0% +converges at an extremely fast rate +usually it's quadratic conversions which + + align:start position:0% +usually it's quadratic conversions which + + + align:start position:0% +usually it's quadratic conversions which +means that every time you make one step + + align:start position:0% +means that every time you make one step + + + align:start position:0% +means that every time you make one step +you improve the accuracy of your + + align:start position:0% +you improve the accuracy of your + + + align:start position:0% +you improve the accuracy of your +Solution by two + + align:start position:0% +Solution by two + + + align:start position:0% +Solution by two +digits + + align:start position:0% +digits + + + align:start position:0% +digits +okay uh if that's something you you're + + align:start position:0% +okay uh if that's something you you're + + + align:start position:0% +okay uh if that's something you you're +vely interested in I highly recommend + + align:start position:0% +vely interested in I highly recommend + + + align:start position:0% +vely interested in I highly recommend +that you take a class on nonlinear + + align:start position:0% +that you take a class on nonlinear + + + align:start position:0% +that you take a class on nonlinear +optimization it's a fascinating topic + + align:start position:0% +optimization it's a fascinating topic + + + align:start position:0% +optimization it's a fascinating topic +unfortunately we don't have much time + + align:start position:0% +unfortunately we don't have much time + + + align:start position:0% +unfortunately we don't have much time +but it starts to in being more and more + + align:start position:0% +but it starts to in being more and more + + + align:start position:0% +but it starts to in being more and more +intertwined with high dimensional + + align:start position:0% +intertwined with high dimensional + + + align:start position:0% +intertwined with high dimensional +statistics and and machine + + align:start position:0% +statistics and and machine + + + align:start position:0% +statistics and and machine +learning that's about div I mean it's + + align:start position:0% +learning that's about div I mean it's + + + align:start position:0% +learning that's about div I mean it's +it's an algorithm's class typically but + + align:start position:0% +it's an algorithm's class typically but + + + align:start position:0% +it's an algorithm's class typically but +it's very much um uh maybe more + + align:start position:0% +it's very much um uh maybe more + + + align:start position:0% +it's very much um uh maybe more +principled it's not a bunch of + + align:start position:0% +principled it's not a bunch of + + + align:start position:0% +principled it's not a bunch of +algorithms that solve a bunch of + + align:start position:0% +algorithms that solve a bunch of + + + align:start position:0% +algorithms that solve a bunch of +problems there's basically one basic + + align:start position:0% +problems there's basically one basic + + + align:start position:0% +problems there's basically one basic +idea which is if I have a convex + + align:start position:0% +idea which is if I have a convex + + + align:start position:0% +idea which is if I have a convex +function I can actually minimize it if I + + align:start position:0% +function I can actually minimize it if I + + + align:start position:0% +function I can actually minimize it if I +have a convex concave function I can + + align:start position:0% +have a convex concave function I can + + + align:start position:0% +have a convex concave function I can +maximize it then there's it evolves + + align:start position:0% +maximize it then there's it evolves + + + align:start position:0% +maximize it then there's it evolves +around similar thing all right so let's + + align:start position:0% +around similar thing all right so let's + + + align:start position:0% +around similar thing all right so let's +stare at this iterative step for a + + align:start position:0% +stare at this iterative step for a + + + align:start position:0% +stare at this iterative step for a +second and pause and ask me let me know + + align:start position:0% +second and pause and ask me let me know + + + align:start position:0% +second and pause and ask me let me know +if you have any + + align:start position:0% + + + + align:start position:0% + +questions okay so of course in a second + + align:start position:0% +questions okay so of course in a second + + + align:start position:0% +questions okay so of course in a second +we will plug in for the L likelihood + + align:start position:0% +we will plug in for the L likelihood + + + align:start position:0% +we will plug in for the L likelihood +this is just a general thing for a + + align:start position:0% +this is just a general thing for a + + + align:start position:0% +this is just a general thing for a +general function f but in a in a second + + align:start position:0% +general function f but in a in a second + + + align:start position:0% +general function f but in a in a second +f is going to be Ln + + align:start position:0% +f is going to be Ln + + + align:start position:0% +f is going to be Ln +okay so if I wanted to implement that + + align:start position:0% +okay so if I wanted to implement that + + + align:start position:0% +okay so if I wanted to implement that +for real I would have to compute the + + align:start position:0% +for real I would have to compute the + + + align:start position:0% +for real I would have to compute the +gradient of Ln at a point XK and I would + + align:start position:0% +gradient of Ln at a point XK and I would + + + align:start position:0% +gradient of Ln at a point XK and I would +have to compute the Hasen at a given + + align:start position:0% +have to compute the Hasen at a given + + + align:start position:0% +have to compute the Hasen at a given +point and + + align:start position:0% +point and + + + align:start position:0% +point and +inverted okay so this is just a basic + + align:start position:0% +inverted okay so this is just a basic + + + align:start position:0% +inverted okay so this is just a basic +algorithm and this as as you can tell + + align:start position:0% +algorithm and this as as you can tell + + + align:start position:0% +algorithm and this as as you can tell +used in no place the fact that Ln was + + align:start position:0% +used in no place the fact that Ln was + + + align:start position:0% +used in no place the fact that Ln was +the log likelihood Associated to some + + align:start position:0% +the log likelihood Associated to some + + + align:start position:0% +the log likelihood Associated to some +canonical exponential family in a + + align:start position:0% +canonical exponential family in a + + + align:start position:0% +canonical exponential family in a +generalized linear model right this + + align:start position:0% +generalized linear model right this + + + align:start position:0% +generalized linear model right this +never showed up so can we use that + + align:start position:0% +never showed up so can we use that + + + align:start position:0% +never showed up so can we use that +somehow uh optimization for long longest + + align:start position:0% +somehow uh optimization for long longest + + + align:start position:0% +somehow uh optimization for long longest +time was about making your problems as + + align:start position:0% +time was about making your problems as + + + align:start position:0% +time was about making your problems as +general as possible accumulating maybe + + align:start position:0% +general as possible accumulating maybe + + + align:start position:0% +general as possible accumulating maybe +in the Inter Point method Theory and + + align:start position:0% +in the Inter Point method Theory and + + + align:start position:0% +in the Inter Point method Theory and +conic programming in the mid 90s and now + + align:start position:0% +conic programming in the mid 90s and now + + + align:start position:0% +conic programming in the mid 90s and now +what optimization is doing is that it's + + align:start position:0% +what optimization is doing is that it's + + + align:start position:0% +what optimization is doing is that it's +very general it says okay if I want to + + align:start position:0% +very general it says okay if I want to + + + align:start position:0% +very general it says okay if I want to +start to go fast I need to exploit as + + align:start position:0% +start to go fast I need to exploit as + + + align:start position:0% +start to go fast I need to exploit as +much structure about my problem as I can + + align:start position:0% +much structure about my problem as I can + + + align:start position:0% +much structure about my problem as I can +and the beauty is that as statisticians + + align:start position:0% +and the beauty is that as statisticians + + + align:start position:0% +and the beauty is that as statisticians +or machine learning people we do have a + + align:start position:0% +or machine learning people we do have a + + + align:start position:0% +or machine learning people we do have a +bunch of very specific problem that we + + align:start position:0% +bunch of very specific problem that we + + + align:start position:0% +bunch of very specific problem that we +want optimizers to solve and they can + + align:start position:0% +want optimizers to solve and they can + + + align:start position:0% +want optimizers to solve and they can +make things run much faster but this did + + align:start position:0% +make things run much faster but this did + + + align:start position:0% +make things run much faster but this did +not require to wait until the 21st + + align:start position:0% +not require to wait until the 21st + + + align:start position:0% +not require to wait until the 21st +century problem with very specific + + align:start position:0% +century problem with very specific + + + align:start position:0% +century problem with very specific +structure of Ros already in the this + + align:start position:0% +structure of Ros already in the this + + + align:start position:0% +structure of Ros already in the this +generalized linear model so what do we + + align:start position:0% +generalized linear model so what do we + + + align:start position:0% +generalized linear model so what do we +know well we know that this log + + align:start position:0% +know well we know that this log + + + align:start position:0% +know well we know that this log +likelihood is really one thing that + + align:start position:0% +likelihood is really one thing that + + + align:start position:0% +likelihood is really one thing that +comes when we're trying to replace an + + align:start position:0% +comes when we're trying to replace an + + + align:start position:0% +comes when we're trying to replace an +expectation by an average and then doing + + align:start position:0% +expectation by an average and then doing + + + align:start position:0% +expectation by an average and then doing +something fency right that was our + + align:start position:0% +something fency right that was our + + + align:start position:0% +something fency right that was our +statistical hammer and remember when we + + align:start position:0% +statistical hammer and remember when we + + + align:start position:0% +statistical hammer and remember when we +introduced likelihood maximization we + + align:start position:0% +introduced likelihood maximization we + + + align:start position:0% +introduced likelihood maximization we +just said what we really want to do is + + align:start position:0% +just said what we really want to do is + + + align:start position:0% +just said what we really want to do is +to minimize the K right that's the thing + + align:start position:0% +to minimize the K right that's the thing + + + align:start position:0% +to minimize the K right that's the thing +we wanted to minimize the K Divergence + + align:start position:0% +we wanted to minimize the K Divergence + + + align:start position:0% +we wanted to minimize the K Divergence +between two distributions the true one + + align:start position:0% +between two distributions the true one + + + align:start position:0% +between two distributions the true one +and the one that's parameterized by some + + align:start position:0% +and the one that's parameterized by some + + + align:start position:0% +and the one that's parameterized by some +unknown Theta and we're trying to + + align:start position:0% +unknown Theta and we're trying to + + + align:start position:0% +unknown Theta and we're trying to +minimize that over Theta and we said + + align:start position:0% +minimize that over Theta and we said + + + align:start position:0% +minimize that over Theta and we said +well I don't know what this is because + + align:start position:0% +well I don't know what this is because + + + align:start position:0% +well I don't know what this is because +it's an expectation with respect to some + + align:start position:0% +it's an expectation with respect to some + + + align:start position:0% +it's an expectation with respect to some +unknown distribution so let me just + + align:start position:0% +unknown distribution so let me just + + + align:start position:0% +unknown distribution so let me just +replace the expectation with respect to + + align:start position:0% +replace the expectation with respect to + + + align:start position:0% +replace the expectation with respect to +my unknown distribution by an average + + align:start position:0% +my unknown distribution by an average + + + align:start position:0% +my unknown distribution by an average +over my data points and that's how we + + align:start position:0% +over my data points and that's how we + + + align:start position:0% +over my data points and that's how we +Justified the existence of the log + + align:start position:0% +Justified the existence of the log + + + align:start position:0% +Justified the existence of the log +likelihood maximization + + align:start position:0% +likelihood maximization + + + align:start position:0% +likelihood maximization +problem but + + align:start position:0% +problem but + + + align:start position:0% +problem but +here I actually + + align:start position:0% +here I actually + + + align:start position:0% +here I actually +I might be able to compute this + + align:start position:0% +I might be able to compute this + + + align:start position:0% +I might be able to compute this +expectation at least partially where I + + align:start position:0% +expectation at least partially where I + + + align:start position:0% +expectation at least partially where I +need it and what we're going to do is + + align:start position:0% +need it and what we're going to do is + + + align:start position:0% +need it and what we're going to do is +we're going to say + + align:start position:0% +we're going to say + + + align:start position:0% +we're going to say +okay since at a given point XK say let + + align:start position:0% +okay since at a given point XK say let + + + align:start position:0% +okay since at a given point XK say let +me call it here Theta I'm trying to find + + align:start position:0% +me call it here Theta I'm trying to find + + + align:start position:0% +me call it here Theta I'm trying to find +the inverse of the + + align:start position:0% +the inverse of the + + + align:start position:0% +the inverse of the +hashen of my log likelihood right so if + + align:start position:0% +hashen of my log likelihood right so if + + + align:start position:0% +hashen of my log likelihood right so if +you look at the previous one as I said + + align:start position:0% +you look at the previous one as I said + + + align:start position:0% +you look at the previous one as I said +we're going to have to compute the + + align:start position:0% +we're going to have to compute the + + + align:start position:0% +we're going to have to compute the +hashen H sub Ln of XK and then invert it + + align:start position:0% +hashen H sub Ln of XK and then invert it + + + align:start position:0% +hashen H sub Ln of XK and then invert it +but let's forget about the inversion + + align:start position:0% +but let's forget about the inversion + + + align:start position:0% +but let's forget about the inversion +step for a second we have to compute the + + align:start position:0% +step for a second we have to compute the + + + align:start position:0% +step for a second we have to compute the +Hasen this is because we're trying this + + align:start position:0% +Hasen this is because we're trying this + + + align:start position:0% +Hasen this is because we're trying this +is the Hasen of the function we're + + align:start position:0% +is the Hasen of the function we're + + + align:start position:0% +is the Hasen of the function we're +trying to minimize but if I could + + align:start position:0% +trying to minimize but if I could + + + align:start position:0% +trying to minimize but if I could +actually replace it not by the function + + align:start position:0% +actually replace it not by the function + + + align:start position:0% +actually replace it not by the function +I'm trying to minimize to maximize sorry + + align:start position:0% +I'm trying to minimize to maximize sorry + + + align:start position:0% +I'm trying to minimize to maximize sorry +the log likelihood but really by the + + align:start position:0% +the log likelihood but really by the + + + align:start position:0% +the log likelihood but really by the +function I wish I was actually Maxim + + align:start position:0% +function I wish I was actually Maxim + + + align:start position:0% +function I wish I was actually Maxim +minimizing which is the K right then + + align:start position:0% +minimizing which is the K right then + + + align:start position:0% +minimizing which is the K right then +that would be really nice and what + + align:start position:0% +that would be really nice and what + + + align:start position:0% +that would be really nice and what +happens is that since I'm actually + + align:start position:0% +happens is that since I'm actually + + + align:start position:0% +happens is that since I'm actually +trying to find this at a given XK I can + + align:start position:0% +trying to find this at a given XK I can + + + align:start position:0% +trying to find this at a given XK I can +always pretend that this x key that I + + align:start position:0% +always pretend that this x key that I + + + align:start position:0% +always pretend that this x key that I +have in my current iteration is the true + + align:start position:0% +have in my current iteration is the true + + + align:start position:0% +have in my current iteration is the true +one and compute my expectations respect + + align:start position:0% +one and compute my expectations respect + + + align:start position:0% +one and compute my expectations respect +to that guy and what happens is that I + + align:start position:0% +to that guy and what happens is that I + + + align:start position:0% +to that guy and what happens is that I +know that when I compute the expectation + + align:start position:0% +know that when I compute the expectation + + + align:start position:0% +know that when I compute the expectation +of the Hasen of the log likelihood at a + + align:start position:0% +of the Hasen of the log likelihood at a + + + align:start position:0% +of the Hasen of the log likelihood at a +given Theta and when I take the + + align:start position:0% +given Theta and when I take the + + + align:start position:0% +given Theta and when I take the +expectation with respect to the same + + align:start position:0% +expectation with respect to the same + + + align:start position:0% +expectation with respect to the same +Theta what I get out is negative Fisher + + align:start position:0% +Theta what I get out is negative Fisher + + + align:start position:0% +Theta what I get out is negative Fisher +information right the Fisher information + + align:start position:0% +information right the Fisher information + + + align:start position:0% +information right the Fisher information +was defined in two ways as the + + align:start position:0% +was defined in two ways as the + + + align:start position:0% +was defined in two ways as the +expectation of the square of the + + align:start position:0% +expectation of the square of the + + + align:start position:0% +expectation of the square of the +derivative or the um expectation + + align:start position:0% +derivative or the um expectation + + + align:start position:0% +derivative or the um expectation +negative the expectation of the second + + align:start position:0% +negative the expectation of the second + + + align:start position:0% +negative the expectation of the second +dtive of the log + + align:start position:0% +dtive of the log + + + align:start position:0% +dtive of the log +like and + + align:start position:0% +like and + + + align:start position:0% +like and +so now I'm doing some sort of a leap of + + align:start position:0% +so now I'm doing some sort of a leap of + + + align:start position:0% +so now I'm doing some sort of a leap of +faith here because this Theta there's no + + align:start position:0% +faith here because this Theta there's no + + + align:start position:0% +faith here because this Theta there's no +way the Theta which is the current XK + + align:start position:0% +way the Theta which is the current XK + + + align:start position:0% +way the Theta which is the current XK +that's the current Theta at which I'm + + align:start position:0% +that's the current Theta at which I'm + + + align:start position:0% +that's the current Theta at which I'm +actually doing this optimization I'm + + align:start position:0% +actually doing this optimization I'm + + + align:start position:0% +actually doing this optimization I'm +actually pretending that this is the + + align:start position:0% +actually pretending that this is the + + + align:start position:0% +actually pretending that this is the +right + + align:start position:0% + + + + align:start position:0% + +one but uh what's going to change by + + align:start position:0% +one but uh what's going to change by + + + align:start position:0% +one but uh what's going to change by +doing this is that it's going to make my + + align:start position:0% +doing this is that it's going to make my + + + align:start position:0% +doing this is that it's going to make my +life easier because when I take + + align:start position:0% +life easier because when I take + + + align:start position:0% +life easier because when I take +expectations I tend to have when I will + + align:start position:0% +expectations I tend to have when I will + + + align:start position:0% +expectations I tend to have when I will +see that when we look at the + + align:start position:0% +see that when we look at the + + + align:start position:0% +see that when we look at the +hhen it's so the hhen as essentially the + + align:start position:0% +hhen it's so the hhen as essentially the + + + align:start position:0% +hhen it's so the hhen as essentially the +derivative of uh say a product is going + + align:start position:0% +derivative of uh say a product is going + + + align:start position:0% +derivative of uh say a product is going +to be the sum of two terms right the + + align:start position:0% +to be the sum of two terms right the + + + align:start position:0% +to be the sum of two terms right the +derivative of U * V is U Prime V plus UV + + align:start position:0% +derivative of U * V is U Prime V plus UV + + + align:start position:0% +derivative of U * V is U Prime V plus UV +prime one of those two terms is actually + + align:start position:0% +prime one of those two terms is actually + + + align:start position:0% +prime one of those two terms is actually +going to have expectations zero and + + align:start position:0% +going to have expectations zero and + + + align:start position:0% +going to have expectations zero and +that's going to make my life very easy + + align:start position:0% +that's going to make my life very easy + + + align:start position:0% +that's going to make my life very easy +when I take expectations and basically + + align:start position:0% +when I take expectations and basically + + + align:start position:0% +when I take expectations and basically +going to just have one term that's going + + align:start position:0% +going to just have one term that's going + + + align:start position:0% +going to just have one term that's going +to go away and so in particular my + + align:start position:0% +to go away and so in particular my + + + align:start position:0% +to go away and so in particular my +formula is just by the virtue of taking + + align:start position:0% +formula is just by the virtue of taking + + + align:start position:0% +formula is just by the virtue of taking +this expectation before inverting the + + align:start position:0% +this expectation before inverting the + + + align:start position:0% +this expectation before inverting the +Hess is going to just shrink the size of + + align:start position:0% +Hess is going to just shrink the size of + + + align:start position:0% +Hess is going to just shrink the size of +my formulas by + + align:start position:0% +my formulas by + + + align:start position:0% +my formulas by +half okay so let's see how this works + + align:start position:0% +half okay so let's see how this works + + + align:start position:0% +half okay so let's see how this works +you don't have to believe me uh is there + + align:start position:0% +you don't have to believe me uh is there + + + align:start position:0% +you don't have to believe me uh is there +any question about this slide you gu + + align:start position:0% +any question about this slide you gu + + + align:start position:0% +any question about this slide you gu +remember when we were doing maximum + + align:start position:0% +remember when we were doing maximum + + + align:start position:0% +remember when we were doing maximum +likelihood estimation and you know + + align:start position:0% +likelihood estimation and you know + + + align:start position:0% +likelihood estimation and you know +Fisher information and the KE Divergence + + align:start position:0% +Fisher information and the KE Divergence + + + align:start position:0% +Fisher information and the KE Divergence +Etc + + align:start position:0% + + + + align:start position:0% + +yeah because that's what we're really + + align:start position:0% +yeah because that's what we're really + + + align:start position:0% +yeah because that's what we're really +trying to minimize + + align:start position:0% + + + + align:start position:0% + +yeah + + align:start position:0% +yeah + + + align:start position:0% +yeah +so there's something you need to uh + + align:start position:0% +so there's something you need to uh + + + align:start position:0% +so there's something you need to uh +trust me with which is that the + + align:start position:0% +trust me with which is that the + + + align:start position:0% +trust me with which is that the +expectation of H of Ln is actually h of + + align:start position:0% +expectation of H of Ln is actually h of + + + align:start position:0% +expectation of H of Ln is actually h of +the expectation of + + align:start position:0% +the expectation of + + + align:start position:0% +the expectation of +Ln all + + align:start position:0% +Ln all + + + align:start position:0% +Ln all +right yeah it's true right because the + + align:start position:0% +right yeah it's true right because the + + + align:start position:0% +right yeah it's true right because the +derivative taking derivative is a linear + + align:start position:0% +derivative taking derivative is a linear + + + align:start position:0% +derivative taking derivative is a linear +operator and we actually used that + + align:start position:0% +operator and we actually used that + + + align:start position:0% +operator and we actually used that +several times when we said expectation + + align:start position:0% +several times when we said expectation + + + align:start position:0% +several times when we said expectation +of second derivative well actually + + align:start position:0% +of second derivative well actually + + + align:start position:0% +of second derivative well actually +expectation of partial of L with respect + + align:start position:0% +expectation of partial of L with respect + + + align:start position:0% +expectation of partial of L with respect +to Theta is equal to zero remember we + + align:start position:0% +to Theta is equal to zero remember we + + + align:start position:0% +to Theta is equal to zero remember we +did that it's basically what we use + + align:start position:0% + + + + align:start position:0% + +right that's the log + + align:start position:0% + + + + align:start position:0% + +likelihood + + align:start position:0% + + + + align:start position:0% + +yeah so + + align:start position:0% +yeah so + + + align:start position:0% +yeah so +actually Ln is typically not normalized + + align:start position:0% +actually Ln is typically not normalized + + + align:start position:0% +actually Ln is typically not normalized +so I really should talk about Ln Over N + + align:start position:0% +so I really should talk about Ln Over N + + + align:start position:0% +so I really should talk about Ln Over N +okay but let's see that okay + + align:start position:0% +okay but let's see that okay + + + align:start position:0% +okay but let's see that okay +so if I have IID observations that + + align:start position:0% +so if I have IID observations that + + + align:start position:0% +so if I have IID observations that +should be pretty obvious okay so if I + + align:start position:0% +should be pretty obvious okay so if I + + + align:start position:0% +should be pretty obvious okay so if I +have IID say X1 xn with + + align:start position:0% + + + + align:start position:0% + +density F Theta and if I look at log F + + align:start position:0% +density F Theta and if I look at log F + + + align:start position:0% +density F Theta and if I look at log F +Theta of x i sum from I one to n as I + + align:start position:0% +Theta of x i sum from I one to n as I + + + align:start position:0% +Theta of x i sum from I one to n as I +said I need to actually have a one over + + align:start position:0% +said I need to actually have a one over + + + align:start position:0% +said I need to actually have a one over +n here when I look at the expectation + + align:start position:0% +n here when I look at the expectation + + + align:start position:0% +n here when I look at the expectation +they all have the same expectation right + + align:start position:0% +they all have the same expectation right + + + align:start position:0% +they all have the same expectation right +so this is actually indeed equal to um + + align:start position:0% +so this is actually indeed equal to um + + + align:start position:0% +so this is actually indeed equal to um +negative KL plus a constant okay and + + align:start position:0% +negative KL plus a constant okay and + + + align:start position:0% +negative KL plus a constant okay and +negative K is because this if I sorry if + + align:start position:0% +negative K is because this if I sorry if + + + align:start position:0% +negative K is because this if I sorry if +I look at the expectation so the + + align:start position:0% +I look at the expectation so the + + + align:start position:0% +I look at the expectation so the +expectation of this guy is just the + + align:start position:0% +expectation of this guy is just the + + + align:start position:0% +expectation of this guy is just the +expectation of one of + + align:start position:0% + + + + align:start position:0% + +them all right so I just do expectation + + align:start position:0% +them all right so I just do expectation + + + align:start position:0% +them all right so I just do expectation +Theta + + align:start position:0% +Theta + + + align:start position:0% +Theta +okay + + align:start position:0% +okay + + + align:start position:0% +okay +agreed the K remember the K was + + align:start position:0% +agreed the K remember the K was + + + align:start position:0% +agreed the K remember the K was +expectation Theta log F Theta divided by + + align:start position:0% +expectation Theta log F Theta divided by + + + align:start position:0% +expectation Theta log F Theta divided by +F so that's between P Theta and P Theta + + align:start position:0% +F so that's between P Theta and P Theta + + + align:start position:0% +F so that's between P Theta and P Theta +Prime and that's uh well no sorry that's + + align:start position:0% +Prime and that's uh well no sorry that's + + + align:start position:0% +Prime and that's uh well no sorry that's +the true + + align:start position:0% +the true + + + align:start position:0% +the true +p and let's call it f p Theta right so + + align:start position:0% +p and let's call it f p Theta right so + + + align:start position:0% +p and let's call it f p Theta right so +that's the that's what showed up which + + align:start position:0% +that's the that's what showed up which + + + align:start position:0% +that's the that's what showed up which +is indeed equal to expect minus + + align:start position:0% +is indeed equal to expect minus + + + align:start position:0% +is indeed equal to expect minus +expectation Theta log F theta plus log + + align:start position:0% +expectation Theta log F theta plus log + + + align:start position:0% +expectation Theta log F theta plus log +of f which is just a + + align:start position:0% +of f which is just a + + + align:start position:0% +of f which is just a +constant with respect to Theta right + + align:start position:0% +constant with respect to Theta right + + + align:start position:0% +constant with respect to Theta right +that's just the thing that's up there it + + align:start position:0% +that's just the thing that's up there it + + + align:start position:0% +that's just the thing that's up there it +doesn't matter + + align:start position:0% +doesn't matter + + + align:start position:0% +doesn't matter +okay so this is uh what shows up here + + align:start position:0% +okay so this is uh what shows up here + + + align:start position:0% +okay so this is uh what shows up here +and just the fact that I have this one + + align:start position:0% +and just the fact that I have this one + + + align:start position:0% +and just the fact that I have this one +over n doesn't change because they're + + align:start position:0% +over n doesn't change because they're + + + align:start position:0% +over n doesn't change because they're +IID now when I have things that are not + + align:start position:0% +IID now when I have things that are not + + + align:start position:0% +IID now when I have things that are not +IID because what I really had was y1 YN + + align:start position:0% +IID because what I really had was y1 YN + + + align:start position:0% +IID because what I really had was y1 YN +and Yi at at density F Theta I which is + + align:start position:0% +and Yi at at density F Theta I which is + + + align:start position:0% +and Yi at at density F Theta I which is +just the conditional density given XI + + align:start position:0% +just the conditional density given XI + + + align:start position:0% +just the conditional density given XI +then I could still write this and now + + align:start position:0% +then I could still write this and now + + + align:start position:0% +then I could still write this and now +when I look at the expectation of this + + align:start position:0% +when I look at the expectation of this + + + align:start position:0% +when I look at the expectation of this +guy what I'm going to be left with is + + align:start position:0% + + + + align:start position:0% + +just 1/ n sum from I = 1 to n of the + + align:start position:0% +just 1/ n sum from I = 1 to n of the + + + align:start position:0% +just 1/ n sum from I = 1 to n of the +expectation of + + align:start position:0% +expectation of + + + align:start position:0% +expectation of +log F Theta I of + + align:start position:0% +log F Theta I of + + + align:start position:0% +log F Theta I of +Yi okay and it's basically the same + + align:start position:0% +Yi okay and it's basically the same + + + align:start position:0% +Yi okay and it's basically the same +thing except that I have a one over n + + align:start position:0% +thing except that I have a one over n + + + align:start position:0% +thing except that I have a one over n +expectation in front and I didn't tell + + align:start position:0% +expectation in front and I didn't tell + + + align:start position:0% +expectation in front and I didn't tell +you this because I only show show you + + align:start position:0% +you this because I only show show you + + + align:start position:0% +you this because I only show show you +what the k Divergence was for between + + align:start position:0% +what the k Divergence was for between + + + align:start position:0% +what the k Divergence was for between +one between two uh distributions but + + align:start position:0% +one between two uh distributions but + + + align:start position:0% +one between two uh distributions but +here I'm telling you what the k uh is + + align:start position:0% +here I'm telling you what the k uh is + + + align:start position:0% +here I'm telling you what the k uh is +between uh two products of distributions + + align:start position:0% +between uh two products of distributions + + + align:start position:0% +between uh two products of distributions +that might that are independent but not + + align:start position:0% +that might that are independent but not + + + align:start position:0% +that might that are independent but not +necessarily identically + + align:start position:0% +necessarily identically + + + align:start position:0% +necessarily identically +distributed + + align:start position:0% + + + + align:start position:0% + +okay but that's what's going to show up + + align:start position:0% +okay but that's what's going to show up + + + align:start position:0% +okay but that's what's going to show up +just because it's a product of things so + + align:start position:0% +just because it's a product of things so + + + align:start position:0% +just because it's a product of things so +when you have the log it's just going to + + align:start position:0% +when you have the log it's just going to + + + align:start position:0% +when you have the log it's just going to +be a sum + + align:start position:0% + + + + align:start position:0% + +other + + align:start position:0% + + + + align:start position:0% + +questions all right so what do we do + + align:start position:0% +questions all right so what do we do + + + align:start position:0% +questions all right so what do we do +here well as I said now we know that the + + align:start position:0% +here well as I said now we know that the + + + align:start position:0% +here well as I said now we know that the +uh expectation of H is negative Fisher + + align:start position:0% +uh expectation of H is negative Fisher + + + align:start position:0% +uh expectation of H is negative Fisher +information so rather than putting H + + align:start position:0% +information so rather than putting H + + + align:start position:0% +information so rather than putting H +inverse in my iterates for Newton rafson + + align:start position:0% +inverse in my iterates for Newton rafson + + + align:start position:0% +inverse in my iterates for Newton rafson +I just should I'm just going to put the + + align:start position:0% +I just should I'm just going to put the + + + align:start position:0% +I just should I'm just going to put the +inverse fissure information and uh + + align:start position:0% +inverse fissure information and uh + + + align:start position:0% +inverse fissure information and uh +remember I had a minus sign in front so + + align:start position:0% +remember I had a minus sign in front so + + + align:start position:0% +remember I had a minus sign in front so +I'm just going to pick up a plus sign + + align:start position:0% +I'm just going to pick up a plus sign + + + align:start position:0% +I'm just going to pick up a plus sign +now just because I is negative the + + align:start position:0% +now just because I is negative the + + + align:start position:0% +now just because I is negative the +expectation of the of the + + align:start position:0% +expectation of the of the + + + align:start position:0% +expectation of the of the +H and this guy has essentially the same + + align:start position:0% +H and this guy has essentially the same + + + align:start position:0% +H and this guy has essentially the same +conversions properties uh and it just + + align:start position:0% +conversions properties uh and it just + + + align:start position:0% +conversions properties uh and it just +happens that it's easier to compute I + + align:start position:0% +happens that it's easier to compute I + + + align:start position:0% +happens that it's easier to compute I +than HLM and uh that's it that's really + + align:start position:0% +than HLM and uh that's it that's really + + + align:start position:0% +than HLM and uh that's it that's really +why you want to do this + + align:start position:0% +why you want to do this + + + align:start position:0% +why you want to do this +now you might say that well if I use + + align:start position:0% +now you might say that well if I use + + + align:start position:0% +now you might say that well if I use +more + + align:start position:0% +more + + + align:start position:0% +more +information uh I should do better right + + align:start position:0% +information uh I should do better right + + + align:start position:0% +information uh I should do better right +but it's actually not necessarily true + + align:start position:0% +but it's actually not necessarily true + + + align:start position:0% +but it's actually not necessarily true +for several reasons but let's say that + + align:start position:0% +for several reasons but let's say that + + + align:start position:0% +for several reasons but let's say that +one is probably the fact that I did not + + align:start position:0% +one is probably the fact that I did not + + + align:start position:0% +one is probably the fact that I did not +use more information every step when I + + align:start position:0% +use more information every step when I + + + align:start position:0% +use more information every step when I +was Computing this thing at XK I + + align:start position:0% +was Computing this thing at XK I + + + align:start position:0% +was Computing this thing at XK I +actually pretended that at Theta K the + + align:start position:0% +actually pretended that at Theta K the + + + align:start position:0% +actually pretended that at Theta K the +true distribution was the one + + align:start position:0% +true distribution was the one + + + align:start position:0% +true distribution was the one +distributed according to Theta K and + + align:start position:0% +distributed according to Theta K and + + + align:start position:0% +distributed according to Theta K and +that was not true this is only true at + + align:start position:0% +that was not true this is only true at + + + align:start position:0% +that was not true this is only true at +when Theta K becomes close to the true + + align:start position:0% +when Theta K becomes close to the true + + + align:start position:0% +when Theta K becomes close to the true +Theta and so in a way I what I gained I + + align:start position:0% +Theta and so in a way I what I gained I + + + align:start position:0% +Theta and so in a way I what I gained I +lost again by making this uh this thing + + align:start position:0% +lost again by making this uh this thing + + + align:start position:0% +lost again by making this uh this thing +it's just really a matter of simple + + align:start position:0% +it's just really a matter of simple + + + align:start position:0% +it's just really a matter of simple +computation so let's just see it on a + + align:start position:0% +computation so let's just see it on a + + + align:start position:0% +computation so let's just see it on a +particular example actually on this + + align:start position:0% +particular example actually on this + + + align:start position:0% +particular example actually on this +example it's not going to look much + + align:start position:0% +example it's not going to look much + + + align:start position:0% +example it's not going to look much +simpler uh it's actually going to be the + + align:start position:0% +simpler uh it's actually going to be the + + + align:start position:0% +simpler uh it's actually going to be the +same um all right so I'm going to have + + align:start position:0% +same um all right so I'm going to have + + + align:start position:0% +same um all right so I'm going to have +the uh Burnley example right so we know + + align:start position:0% +the uh Burnley example right so we know + + + align:start position:0% +the uh Burnley example right so we know +that Burnley belongs to the + + align:start position:0% +that Burnley belongs to the + + + align:start position:0% +that Burnley belongs to the +canonical exponential + + align:start position:0% +canonical exponential + + + align:start position:0% +canonical exponential +family and uh essentially all I need to + + align:start position:0% +family and uh essentially all I need to + + + align:start position:0% +family and uh essentially all I need to +tell you is what B is and + + align:start position:0% +tell you is what B is and + + + align:start position:0% +tell you is what B is and +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +B of theta for Burn only is log 1+ e + + align:start position:0% +B of theta for Burn only is log 1+ e + + + align:start position:0% +B of theta for Burn only is log 1+ e +Theta right we computed that + + align:start position:0% +Theta right we computed that + + + align:start position:0% +Theta right we computed that +okay and so when I look at my log + + align:start position:0% + + + + align:start position:0% + +likelihood it's going to look like the + + align:start position:0% +likelihood it's going to look like the + + + align:start position:0% +likelihood it's going to look like the +sum from I = one to + + align:start position:0% +sum from I = one to + + + align:start position:0% +sum from I = one to +n of y + + align:start position:0% +n of y + + + align:start position:0% +n of y +i okay so here I'm going to actually use + + align:start position:0% +i okay so here I'm going to actually use + + + align:start position:0% +i okay so here I'm going to actually use +the canonical length so it's going to be + + align:start position:0% +the canonical length so it's going to be + + + align:start position:0% +the canonical length so it's going to be +X I transpose beta minus log 1 + + + align:start position:0% +X I transpose beta minus log 1 + + + + align:start position:0% +X I transpose beta minus log 1 + +exponential X I transpose + + align:start position:0% + + + + align:start position:0% + +beta and five for this guy is equal to + + align:start position:0% +beta and five for this guy is equal to + + + align:start position:0% +beta and five for this guy is equal to +one + + align:start position:0% +one + + + align:start position:0% +one +is it clear for everyone what I did okay + + align:start position:0% +is it clear for everyone what I did okay + + + align:start position:0% +is it clear for everyone what I did okay +so this remember the the the density + + align:start position:0% +so this remember the the the density + + + align:start position:0% +so this remember the the the density +right so that was really just uh so the + + align:start position:0% +right so that was really just uh so the + + + align:start position:0% +right so that was really just uh so the +pmf was + + align:start position:0% +pmf was + + + align:start position:0% +pmf was +exponential y Theta minus log 1 + e + + align:start position:0% +exponential y Theta minus log 1 + e + + + align:start position:0% +exponential y Theta minus log 1 + e +Theta there was actually no + + align:start position:0% +Theta there was actually no + + + align:start position:0% +Theta there was actually no +normalization that's just the density of + + align:start position:0% +normalization that's just the density of + + + align:start position:0% +normalization that's just the density of +a + + align:start position:0% + + + + align:start position:0% + +burnly and Theta is + + align:start position:0% + + + + align:start position:0% + +actually log p over 1 minus + + align:start position:0% +actually log p over 1 minus + + + align:start position:0% +actually log p over 1 minus +p and so that's what actually gives me + + align:start position:0% +p and so that's what actually gives me + + + align:start position:0% +p and so that's what actually gives me +what my uh since p is the expectation + + align:start position:0% +what my uh since p is the expectation + + + align:start position:0% +what my uh since p is the expectation +this is actually giving me also my + + align:start position:0% +this is actually giving me also my + + + align:start position:0% +this is actually giving me also my +canonical link which is the logit link + + align:start position:0% +canonical link which is the logit link + + + align:start position:0% +canonical link which is the logit link +we saw that last time and so if I start + + align:start position:0% +we saw that last time and so if I start + + + align:start position:0% +we saw that last time and so if I start +taking the log of this guy and summing + + align:start position:0% +taking the log of this guy and summing + + + align:start position:0% +taking the log of this guy and summing +over n and replacing Theta by X I + + align:start position:0% +over n and replacing Theta by X I + + + align:start position:0% +over n and replacing Theta by X I +transpose beta which is the what the + + align:start position:0% +transpose beta which is the what the + + + align:start position:0% +transpose beta which is the what the +canonical link tells me to do I get this + + align:start position:0% +canonical link tells me to do I get this + + + align:start position:0% +canonical link tells me to do I get this +guy is that clear for everyone if it's + + align:start position:0% +guy is that clear for everyone if it's + + + align:start position:0% +guy is that clear for everyone if it's +not please redo this step on your own + + align:start position:0% + + + + align:start position:0% + +okay so I want to maximize this function + + align:start position:0% +okay so I want to maximize this function + + + align:start position:0% +okay so I want to maximize this function +sorry so I want to maximize this + + align:start position:0% +sorry so I want to maximize this + + + align:start position:0% +sorry so I want to maximize this +function over there on the first line as + + align:start position:0% +function over there on the first line as + + + align:start position:0% +function over there on the first line as +a function of + + align:start position:0% +a function of + + + align:start position:0% +a function of +beta and so to do this I want to use + + align:start position:0% +beta and so to do this I want to use + + + align:start position:0% +beta and so to do this I want to use +either um Newton rafson or what I call + + align:start position:0% +either um Newton rafson or what I call + + + align:start position:0% +either um Newton rafson or what I call +fisser scoring so Fisher scoring is the + + align:start position:0% +fisser scoring so Fisher scoring is the + + + align:start position:0% +fisser scoring so Fisher scoring is the +second one when you replace the hen by + + align:start position:0% +second one when you replace the hen by + + + align:start position:0% +second one when you replace the hen by +negative Fisher + + align:start position:0% +negative Fisher + + + align:start position:0% +negative Fisher +information right so I replace these two + + align:start position:0% +information right so I replace these two + + + align:start position:0% +information right so I replace these two +things and so I first take the gradient + + align:start position:0% +things and so I first take the gradient + + + align:start position:0% +things and so I first take the gradient +okay so let's take the gradient R of + + align:start position:0% + + + + align:start position:0% + +Ln + + align:start position:0% +Ln + + + align:start position:0% +Ln +uh so the gradient of Ln is going to be + + align:start position:0% +uh so the gradient of Ln is going to be + + + align:start position:0% +uh so the gradient of Ln is going to be +sum so here this is of the form Yi which + + align:start position:0% +sum so here this is of the form Yi which + + + align:start position:0% +sum so here this is of the form Yi which +is a scalar times a vector x i beta + + align:start position:0% +is a scalar times a vector x i beta + + + align:start position:0% +is a scalar times a vector x i beta +that's what I erase from here the + + align:start position:0% +that's what I erase from here the + + + align:start position:0% +that's what I erase from here the +derivative of B transpose X the gradient + + align:start position:0% +derivative of B transpose X the gradient + + + align:start position:0% +derivative of B transpose X the gradient +of B transpose X is just B so here I + + align:start position:0% +of B transpose X is just B so here I + + + align:start position:0% +of B transpose X is just B so here I +have just y + + align:start position:0% +have just y + + + align:start position:0% +have just y +ixi okay so that's of the form Yi which + + align:start position:0% +ixi okay so that's of the form Yi which + + + align:start position:0% +ixi okay so that's of the form Yi which +is a scalar time x i which is a + + align:start position:0% +is a scalar time x i which is a + + + align:start position:0% +is a scalar time x i which is a +vector now what about this guy well here + + align:start position:0% +vector now what about this guy well here + + + align:start position:0% +vector now what about this guy well here +I have a function so I'm going to have + + align:start position:0% +I have a function so I'm going to have + + + align:start position:0% +I have a function so I'm going to have +just the usual rule that the the chain + + align:start position:0% +just the usual rule that the the chain + + + align:start position:0% +just the usual rule that the the chain +rule right so that's just going to be + + align:start position:0% +rule right so that's just going to be + + + align:start position:0% +rule right so that's just going to be +one over this + + align:start position:0% +one over this + + + align:start position:0% +one over this +guy and then I need to find the hashen + + align:start position:0% +guy and then I need to find the hashen + + + align:start position:0% +guy and then I need to find the hashen +of this thing so the one is going away + + align:start position:0% +of this thing so the one is going away + + + align:start position:0% +of this thing so the one is going away +and then I apply the chain rule again so + + align:start position:0% +and then I apply the chain rule again so + + + align:start position:0% +and then I apply the chain rule again so +I get e of X I transpose beta and then + + align:start position:0% +I get e of X I transpose beta and then + + + align:start position:0% +I get e of X I transpose beta and then +the HH of this thing + + align:start position:0% +the HH of this thing + + + align:start position:0% +the HH of this thing +which is x i + + align:start position:0% + + + + align:start position:0% + +okay so my hen I can actually my + + align:start position:0% +okay so my hen I can actually my + + + align:start position:0% +okay so my hen I can actually my +gradient sorry I can actually factor out + + align:start position:0% +gradient sorry I can actually factor out + + + align:start position:0% +gradient sorry I can actually factor out +all my XIs and it's going to look like + + align:start position:0% + + + + align:start position:0% + +this my + + align:start position:0% +this my + + + align:start position:0% +this my +gradient is a weighted average or + + align:start position:0% +gradient is a weighted average or + + + align:start position:0% +gradient is a weighted average or +weighted sum of the + + align:start position:0% + + + + align:start position:0% + +XI this will always happen when you have + + align:start position:0% +XI this will always happen when you have + + + align:start position:0% +XI this will always happen when you have +a canonical when you have an generalized + + align:start position:0% +a canonical when you have an generalized + + + align:start position:0% +a canonical when you have an generalized +in your mod and that's pretty clear + + align:start position:0% +in your mod and that's pretty clear + + + align:start position:0% +in your mod and that's pretty clear +where did the XI show up whether it's + + align:start position:0% +where did the XI show up whether it's + + + align:start position:0% +where did the XI show up whether it's +from this guy or that guy the XI came + + align:start position:0% +from this guy or that guy the XI came + + + align:start position:0% +from this guy or that guy the XI came +from the fact that when I take the + + align:start position:0% +from the fact that when I take the + + + align:start position:0% +from the fact that when I take the +gradient of XI transposed beta I have + + align:start position:0% +gradient of XI transposed beta I have + + + align:start position:0% +gradient of XI transposed beta I have +this Vector XI that comes out it's + + align:start position:0% +this Vector XI that comes out it's + + + align:start position:0% +this Vector XI that comes out it's +always going to be the thing that comes + + align:start position:0% +always going to be the thing that comes + + + align:start position:0% +always going to be the thing that comes +out so I will always have something that + + align:start position:0% +out so I will always have something that + + + align:start position:0% +out so I will always have something that +looks like some sum with some weights + + align:start position:0% +looks like some sum with some weights + + + align:start position:0% +looks like some sum with some weights +here of the + + align:start position:0% +here of the + + + align:start position:0% +here of the +X now when I look at the second + + align:start position:0% +X now when I look at the second + + + align:start position:0% +X now when I look at the second +derivative + + align:start position:0% + + + + align:start position:0% + +so same thing I'm just going to take the + + align:start position:0% +so same thing I'm just going to take the + + + align:start position:0% +so same thing I'm just going to take the +derivative of this guy since nothing + + align:start position:0% +derivative of this guy since nothing + + + align:start position:0% +derivative of this guy since nothing +depends on beta here or here I'm just + + align:start position:0% +depends on beta here or here I'm just + + + align:start position:0% +depends on beta here or here I'm just +going to have to take the derivative of + + align:start position:0% +going to have to take the derivative of + + + align:start position:0% +going to have to take the derivative of +this thing and so it's going to be equal + + align:start position:0% +this thing and so it's going to be equal + + + align:start position:0% +this thing and so it's going to be equal +so if I look now at the hen Ln as a + + align:start position:0% +so if I look now at the hen Ln as a + + + align:start position:0% +so if I look now at the hen Ln as a +function of beta I'm going to have sum + + align:start position:0% +function of beta I'm going to have sum + + + align:start position:0% +function of beta I'm going to have sum +from I = 1 to n of well y i what is the + + align:start position:0% +from I = 1 to n of well y i what is the + + + align:start position:0% +from I = 1 to n of well y i what is the +derivative of Yi with respect to + + align:start position:0% + + + + align:start position:0% + +Beta + + align:start position:0% + + + + align:start position:0% + +what + + align:start position:0% +what + + + align:start position:0% +what +yeah zero okay it doesn't depend on beta + + align:start position:0% +yeah zero okay it doesn't depend on beta + + + align:start position:0% +yeah zero okay it doesn't depend on beta +I mean it's distribution does but y + + align:start position:0% +I mean it's distribution does but y + + + align:start position:0% +I mean it's distribution does but y +itself is just a it's just number right + + align:start position:0% +itself is just a it's just number right + + + align:start position:0% +itself is just a it's just number right +so uh this is zero so I'm going to get + + align:start position:0% +so uh this is zero so I'm going to get + + + align:start position:0% +so uh this is zero so I'm going to get +minus and then I'm going to have again + + align:start position:0% +minus and then I'm going to have again + + + align:start position:0% +minus and then I'm going to have again +the chain rule that shows up so I need + + align:start position:0% +the chain rule that shows up so I need + + + align:start position:0% +the chain rule that shows up so I need +to find the derivative of x over 1 + x + + align:start position:0% +to find the derivative of x over 1 + x + + + align:start position:0% +to find the derivative of x over 1 + x +what is the derivative of x over 1 plus + + align:start position:0% +what is the derivative of x over 1 plus + + + align:start position:0% +what is the derivative of x over 1 plus +X actually don't even + + align:start position:0% +X actually don't even + + + align:start position:0% +X actually don't even +know uh so it gives me + + align:start position:0% + + + + align:start position:0% + +uh okay so that's 1 over 1 + x s so + + align:start position:0% +uh okay so that's 1 over 1 + x s so + + + align:start position:0% +uh okay so that's 1 over 1 + x s so +that's + + align:start position:0% +that's + + + align:start position:0% +that's +minus E XI transpose beta sorry no one + + align:start position:0% +minus E XI transpose beta sorry no one + + + align:start position:0% +minus E XI transpose beta sorry no one +divided 1 + E X I transpose beta squar + + align:start position:0% +divided 1 + E X I transpose beta squar + + + align:start position:0% +divided 1 + E X I transpose beta squar +times the derivative of the exponential + + align:start position:0% +times the derivative of the exponential + + + align:start position:0% +times the derivative of the exponential +which is E X I transpose beta and again + + align:start position:0% +which is E X I transpose beta and again + + + align:start position:0% +which is E X I transpose beta and again +x + + align:start position:0% +x + + + align:start position:0% +x +i and then I have this XI that shows up + + align:start position:0% +i and then I have this XI that shows up + + + align:start position:0% +i and then I have this XI that shows up +but since I'm looking for a matrix I'm + + align:start position:0% +but since I'm looking for a matrix I'm + + + align:start position:0% +but since I'm looking for a matrix I'm +going to have x i x i transpose + + align:start position:0% + + + + align:start position:0% + +right okay + + align:start position:0% + + + + align:start position:0% + +so this is + + align:start position:0% +so this is + + + align:start position:0% +so this is +just I know I'm going to need something + + align:start position:0% +just I know I'm going to need something + + + align:start position:0% +just I know I'm going to need something +that looks like a matrix in the end and + + align:start position:0% +that looks like a matrix in the end and + + + align:start position:0% +that looks like a matrix in the end and +so one way you want to think about it is + + align:start position:0% +so one way you want to think about it is + + + align:start position:0% +so one way you want to think about it is +you know this is going to spit out an XI + + align:start position:0% +you know this is going to spit out an XI + + + align:start position:0% +you know this is going to spit out an XI +there's already an XI here so I need to + + align:start position:0% +there's already an XI here so I need to + + + align:start position:0% +there's already an XI here so I need to +so I'm going to have something that + + align:start position:0% +so I'm going to have something that + + + align:start position:0% +so I'm going to have something that +looks like XI and I'm going to have to + + align:start position:0% +looks like XI and I'm going to have to + + + align:start position:0% +looks like XI and I'm going to have to +multiply by another Vector x i and I + + align:start position:0% +multiply by another Vector x i and I + + + align:start position:0% +multiply by another Vector x i and I +want it to form a matrix and so what you + + align:start position:0% +want it to form a matrix and so what you + + + align:start position:0% +want it to form a matrix and so what you +need to do is to take an outer + + align:start position:0% +need to do is to take an outer + + + align:start position:0% +need to do is to take an outer +product and that's it + + align:start position:0% + + + + align:start position:0% + +all + + align:start position:0% + + + + align:start position:0% + +right so now well as a result the + + align:start position:0% +right so now well as a result the + + + align:start position:0% +right so now well as a result the +updating rule is this honestly this is + + align:start position:0% +updating rule is this honestly this is + + + align:start position:0% +updating rule is this honestly this is +not a result of anything I actually + + align:start position:0% +not a result of anything I actually + + + align:start position:0% +not a result of anything I actually +rewrote everything that I had before + + align:start position:0% +rewrote everything that I had before + + + align:start position:0% +rewrote everything that I had before +with a Theta replaced by Beta because + + align:start position:0% +with a Theta replaced by Beta because + + + align:start position:0% +with a Theta replaced by Beta because +it's just painful to rewrite this entire + + align:start position:0% +it's just painful to rewrite this entire + + + align:start position:0% +it's just painful to rewrite this entire +thing put some big parentheses and put + + align:start position:0% +thing put some big parentheses and put + + + align:start position:0% +thing put some big parentheses and put +minus one here + + align:start position:0% +minus one here + + + align:start position:0% +minus one here +okay and uh then I would have to put the + + align:start position:0% +okay and uh then I would have to put the + + + align:start position:0% +okay and uh then I would have to put the +gradient which is this thing + + align:start position:0% +gradient which is this thing + + + align:start position:0% +gradient which is this thing +here so as you can imagine this is not + + align:start position:0% +here so as you can imagine this is not + + + align:start position:0% +here so as you can imagine this is not +super + + align:start position:0% +super + + + align:start position:0% +super +nice um actually uh what's interesting + + align:start position:0% +nice um actually uh what's interesting + + + align:start position:0% +nice um actually uh what's interesting +is you know at some point I mentioned + + align:start position:0% +is you know at some point I mentioned + + + align:start position:0% +is you know at some point I mentioned +those pseudo Newton um method they're + + align:start position:0% +those pseudo Newton um method they're + + + align:start position:0% +those pseudo Newton um method they're +actually doing exactly this they're + + align:start position:0% +actually doing exactly this they're + + + align:start position:0% +actually doing exactly this they're +saying + + align:start position:0% +saying + + + align:start position:0% +saying +oh I'm actually at it each iterations + + align:start position:0% +oh I'm actually at it each iterations + + + align:start position:0% +oh I'm actually at it each iterations +I'm actually going to just take those + + align:start position:0% +I'm actually going to just take those + + + align:start position:0% +I'm actually going to just take those +guys if I'm at iteration K I'm actually + + align:start position:0% +guys if I'm at iteration K I'm actually + + + align:start position:0% +guys if I'm at iteration K I'm actually +just going to sum those guys up to K + + align:start position:0% +just going to sum those guys up to K + + + align:start position:0% +just going to sum those guys up to K +rather than going all the way to n and + + align:start position:0% +rather than going all the way to n and + + + align:start position:0% +rather than going all the way to n and +look at everyone so you're just looking + + align:start position:0% +look at everyone so you're just looking + + + align:start position:0% +look at everyone so you're just looking +at your observations one at a time based + + align:start position:0% +at your observations one at a time based + + + align:start position:0% +at your observations one at a time based +on where you were + + align:start position:0% +on where you were + + + align:start position:0% +on where you were +before okay so you know you have a + + align:start position:0% +before okay so you know you have a + + + align:start position:0% +before okay so you know you have a +matrix you need to invert it so if you + + align:start position:0% +matrix you need to invert it so if you + + + align:start position:0% +matrix you need to invert it so if you +want to be able to invert it you need to + + align:start position:0% +want to be able to invert it you need to + + + align:start position:0% +want to be able to invert it you need to +make sure that the sum with those + + align:start position:0% +make sure that the sum with those + + + align:start position:0% +make sure that the sum with those +weights of XI outer XI or X ixi + + align:start position:0% +weights of XI outer XI or X ixi + + + align:start position:0% +weights of XI outer XI or X ixi +transpose is invertible so that's a + + align:start position:0% +transpose is invertible so that's a + + + align:start position:0% +transpose is invertible so that's a +condition that you need to have and uh + + align:start position:0% +condition that you need to have and uh + + + align:start position:0% +condition that you need to have and uh +well I mean you don't have to because + + align:start position:0% +well I mean you don't have to because + + + align:start position:0% +well I mean you don't have to because +technically you don't need to invert you + + align:start position:0% +technically you don't need to invert you + + + align:start position:0% +technically you don't need to invert you +just need to solve the linear system + + align:start position:0% +just need to solve the linear system + + + align:start position:0% +just need to solve the linear system +uh but that's uh that's actually + + align:start position:0% +uh but that's uh that's actually + + + align:start position:0% +uh but that's uh that's actually +guaranteed in most of the cases if n is + + align:start position:0% +guaranteed in most of the cases if n is + + + align:start position:0% +guaranteed in most of the cases if n is +large enough all right so everybody sees + + align:start position:0% +large enough all right so everybody sees + + + align:start position:0% +large enough all right so everybody sees +what we're doing here okay so now that's + + align:start position:0% +what we're doing here okay so now that's + + + align:start position:0% +what we're doing here okay so now that's +for the + + align:start position:0% +for the + + + align:start position:0% +for the +um Newton rafon if I wanted to actually + + align:start position:0% +um Newton rafon if I wanted to actually + + + align:start position:0% +um Newton rafon if I wanted to actually +do the um Fisher + + align:start position:0% +do the um Fisher + + + align:start position:0% +do the um Fisher +scoring all I would need to do is to + + align:start position:0% +scoring all I would need to do is to + + + align:start position:0% +scoring all I would need to do is to +replace the Hasen here by its + + align:start position:0% +replace the Hasen here by its + + + align:start position:0% +replace the Hasen here by its +expectation when I pretend that the beta + + align:start position:0% +expectation when I pretend that the beta + + + align:start position:0% +expectation when I pretend that the beta +that I have atation k is the true + + align:start position:0% +that I have atation k is the true + + + align:start position:0% +that I have atation k is the true +one what is the expectation of this + + align:start position:0% +one what is the expectation of this + + + align:start position:0% +one what is the expectation of this +thing and when I say + + align:start position:0% +thing and when I say + + + align:start position:0% +thing and when I say +expectation here I'm always talking + + align:start position:0% +expectation here I'm always talking + + + align:start position:0% +expectation here I'm always talking +about conditional expectation of Y given + + align:start position:0% +about conditional expectation of Y given + + + align:start position:0% +about conditional expectation of Y given +X the only distributions that matter + + align:start position:0% +X the only distributions that matter + + + align:start position:0% +X the only distributions that matter +that have mattered in this entire + + align:start position:0% +that have mattered in this entire + + + align:start position:0% +that have mattered in this entire +chapter are condition conditional + + align:start position:0% +chapter are condition conditional + + + align:start position:0% +chapter are condition conditional +expectation of Y given X the conditional + + align:start position:0% +expectation of Y given X the conditional + + + align:start position:0% +expectation of Y given X the conditional +expectation of this thing given X is + + align:start position:0% +expectation of this thing given X is + + + align:start position:0% +expectation of this thing given X is +what + + align:start position:0% + + + + align:start position:0% + +it's itself it does not depend on y it + + align:start position:0% +it's itself it does not depend on y it + + + align:start position:0% +it's itself it does not depend on y it +only depends on the X's so conditionally + + align:start position:0% +only depends on the X's so conditionally + + + align:start position:0% +only depends on the X's so conditionally +on X this thing as far as we're + + align:start position:0% +on X this thing as far as we're + + + align:start position:0% +on X this thing as far as we're +concerned is completely deterministic so + + align:start position:0% +concerned is completely deterministic so + + + align:start position:0% +concerned is completely deterministic so +it's actually equal to its + + align:start position:0% +it's actually equal to its + + + align:start position:0% +it's actually equal to its +expectation and so in this particular + + align:start position:0% +expectation and so in this particular + + + align:start position:0% +expectation and so in this particular +example there's no + + align:start position:0% +example there's no + + + align:start position:0% +example there's no +difference between Fisher + + align:start position:0% +difference between Fisher + + + align:start position:0% +difference between Fisher +scoring and uh uh Newton rafson and the + + align:start position:0% +scoring and uh uh Newton rafson and the + + + align:start position:0% +scoring and uh uh Newton rafson and the +reason is because the gradient no longer + + align:start position:0% +reason is because the gradient no longer + + + align:start position:0% +reason is because the gradient no longer +depends on why I sorry the h no longer + + align:start position:0% +depends on why I sorry the h no longer + + + align:start position:0% +depends on why I sorry the h no longer +depends on on + + align:start position:0% +depends on on + + + align:start position:0% +depends on on +Yi + + align:start position:0% + + + + align:start position:0% + +okay so this slide is just repeating + + align:start position:0% +okay so this slide is just repeating + + + align:start position:0% +okay so this slide is just repeating +some stuff that I've + + align:start position:0% + + + + align:start position:0% + +said + + align:start position:0% + + + + align:start position:0% + +okay so I think this is probably + + align:start position:0% + + + + align:start position:0% + +okay let's go through this + + align:start position:0% +okay let's go through this + + + align:start position:0% +okay let's go through this +actually + + align:start position:0% + + + + align:start position:0% + +um at some point I said that uh Newton + + align:start position:0% +um at some point I said that uh Newton + + + align:start position:0% +um at some point I said that uh Newton +rapson do you have a question + + align:start position:0% + + + + align:start position:0% + +not when you have a canonical + + align:start position:0% + + + + align:start position:0% + +link + + align:start position:0% +link + + + align:start position:0% +link +no uh yeah so you + + align:start position:0% +no uh yeah so you + + + align:start position:0% +no uh yeah so you +know yeah maybe maybe I wanted you to + + align:start position:0% +know yeah maybe maybe I wanted you to + + + align:start position:0% +know yeah maybe maybe I wanted you to +figure that out for yourself but uh okay + + align:start position:0% +figure that out for yourself but uh okay + + + align:start position:0% +figure that out for yourself but uh okay +so Yi times XI transpose beta so + + align:start position:0% +so Yi times XI transpose beta so + + + align:start position:0% +so Yi times XI transpose beta so +essentially you know when I have a + + align:start position:0% +essentially you know when I have a + + + align:start position:0% +essentially you know when I have a +general + + align:start position:0% +general + + + align:start position:0% +general +family what is referring to is that this + + align:start position:0% +family what is referring to is that this + + + align:start position:0% +family what is referring to is that this +is just B of XI transpose beta so I'm + + align:start position:0% +is just B of XI transpose beta so I'm + + + align:start position:0% +is just B of XI transpose beta so I'm +going to take some derivatives and + + align:start position:0% +going to take some derivatives and + + + align:start position:0% +going to take some derivatives and +there's going to be something + + align:start position:0% +there's going to be something + + + align:start position:0% +there's going to be something +complicated coming out of this but I'm + + align:start position:0% +complicated coming out of this but I'm + + + align:start position:0% +complicated coming out of this but I'm +certainly not going to have some Yi + + align:start position:0% +certainly not going to have some Yi + + + align:start position:0% +certainly not going to have some Yi +showing up the only place where Yi shows + + align:start position:0% +showing up the only place where Yi shows + + + align:start position:0% +showing up the only place where Yi shows +up is here now if I take two derivatives + + align:start position:0% +up is here now if I take two derivatives + + + align:start position:0% +up is here now if I take two derivatives +this thing is gone because it's linear + + align:start position:0% +this thing is gone because it's linear + + + align:start position:0% +this thing is gone because it's linear +the first one is going to keep only this + + align:start position:0% +the first one is going to keep only this + + + align:start position:0% +the first one is going to keep only this +guy and the second one is going to make + + align:start position:0% +guy and the second one is going to make + + + align:start position:0% +guy and the second one is going to make +it gone the only way this actually shows + + align:start position:0% +it gone the only way this actually shows + + + align:start position:0% +it gone the only way this actually shows +up is when I have an H here and if I + + align:start position:0% +up is when I have an H here and if I + + + align:start position:0% +up is when I have an H here and if I +have an H then I I can take second + + align:start position:0% +have an H then I I can take second + + + align:start position:0% +have an H then I I can take second +derivatives and this thing is not not + + align:start position:0% +derivatives and this thing is not not + + + align:start position:0% +derivatives and this thing is not not +going to be completely independent of uh + + align:start position:0% +going to be completely independent of uh + + + align:start position:0% +going to be completely independent of uh +beta uh sorry yeah this thing is still + + align:start position:0% +beta uh sorry yeah this thing is still + + + align:start position:0% +beta uh sorry yeah this thing is still +going to depend on beta which means that + + align:start position:0% +going to depend on beta which means that + + + align:start position:0% +going to depend on beta which means that +this Yi term is not going to + + align:start position:0% + + + + align:start position:0% + +disappear I believe we'll see an example + + align:start position:0% +disappear I believe we'll see an example + + + align:start position:0% +disappear I believe we'll see an example +of that or maybe I removed I'm not sure + + align:start position:0% +of that or maybe I removed I'm not sure + + + align:start position:0% +of that or maybe I removed I'm not sure +actually I think we we will see an + + align:start position:0% + + + + align:start position:0% + +example all + + align:start position:0% +example all + + + align:start position:0% +example all +right + + align:start position:0% +right + + + align:start position:0% +right +so let us do uh + + align:start position:0% +so let us do uh + + + align:start position:0% +so let us do uh +iteratively uh Reed Le squares + + align:start position:0% +iteratively uh Reed Le squares + + + align:start position:0% +iteratively uh Reed Le squares +or IR LS which I've actually recently + + align:start position:0% +or IR LS which I've actually recently + + + align:start position:0% +or IR LS which I've actually recently +learned is a term that even though it + + align:start position:0% +learned is a term that even though it + + + align:start position:0% +learned is a term that even though it +was defined in the 50s people still feel + + align:start position:0% +was defined in the 50s people still feel + + + align:start position:0% +was defined in the 50s people still feel +free to use to define to call their new + + align:start position:0% +free to use to define to call their new + + + align:start position:0% +free to use to define to call their new +algorithms which have nothing to do with + + align:start position:0% +algorithms which have nothing to do with + + + align:start position:0% +algorithms which have nothing to do with +this uh this is really something where + + align:start position:0% +this uh this is really something where + + + align:start position:0% +this uh this is really something where +you actually do iteratively reweighted + + align:start position:0% +you actually do iteratively reweighted + + + align:start position:0% +you actually do iteratively reweighted +disir um and so which means that every + + align:start position:0% +disir um and so which means that every + + + align:start position:0% +disir um and so which means that every +step okay let's just actually go through + + align:start position:0% +step okay let's just actually go through + + + align:start position:0% +step okay let's just actually go through +this quickly what is going to be + + align:start position:0% +this quickly what is going to be + + + align:start position:0% +this quickly what is going to be +iteratively weedly SES the way the steps + + align:start position:0% +iteratively weedly SES the way the steps + + + align:start position:0% +iteratively weedly SES the way the steps +that we had here here showed + + align:start position:0% +that we had here here showed + + + align:start position:0% +that we had here here showed +up let's say those + + align:start position:0% +up let's say those + + + align:start position:0% +up let's say those +guys + + align:start position:0% +guys + + + align:start position:0% +guys +xstar is this is when we were actually + + align:start position:0% +xstar is this is when we were actually + + + align:start position:0% +xstar is this is when we were actually +solving this linear + + align:start position:0% +solving this linear + + + align:start position:0% +solving this linear +system right that was the linear system + + align:start position:0% +system right that was the linear system + + + align:start position:0% +system right that was the linear system +we were trying to + + align:start position:0% + + + + align:start position:0% + +solve but solving a linear system can be + + align:start position:0% +solve but solving a linear system can be + + + align:start position:0% +solve but solving a linear system can be +done by Just Trying to minimize right if + + align:start position:0% +done by Just Trying to minimize right if + + + align:start position:0% +done by Just Trying to minimize right if +I have X A and B is the same as + + align:start position:0% +I have X A and B is the same as + + + align:start position:0% +I have X A and B is the same as +minimizing the norm of ax minus b^ 2 + + align:start position:0% +minimizing the norm of ax minus b^ 2 + + + align:start position:0% +minimizing the norm of ax minus b^ 2 +right over + + align:start position:0% +right over + + + align:start position:0% +right over +X right if I can actually find an X for + + align:start position:0% +X right if I can actually find an X for + + + align:start position:0% +X right if I can actually find an X for +which is zero it means that I've + + align:start position:0% +which is zero it means that I've + + + align:start position:0% +which is zero it means that I've +actually solved my problem and so that + + align:start position:0% +actually solved my problem and so that + + + align:start position:0% +actually solved my problem and so that +means that this is actually there's + + align:start position:0% +means that this is actually there's + + + align:start position:0% +means that this is actually there's +actually I can solve linear systems by + + align:start position:0% +actually I can solve linear systems by + + + align:start position:0% +actually I can solve linear systems by +solving least course problems and least + + align:start position:0% +solving least course problems and least + + + align:start position:0% +solving least course problems and least +SES problems are things that + + align:start position:0% +SES problems are things that + + + align:start position:0% +SES problems are things that +statisticians are comfortable solving + + align:start position:0% +statisticians are comfortable solving + + + align:start position:0% +statisticians are comfortable solving +and so all I have to do is to rephrase + + align:start position:0% +and so all I have to do is to rephrase + + + align:start position:0% +and so all I have to do is to rephrase +this as a least ques problem okay and + + align:start position:0% +this as a least ques problem okay and + + + align:start position:0% +this as a least ques problem okay and +you know I could just write it directly + + align:start position:0% +you know I could just write it directly + + + align:start position:0% +you know I could just write it directly +like this but there's a way to + + align:start position:0% +like this but there's a way to + + + align:start position:0% +like this but there's a way to +streamline it a little bit and that's + + align:start position:0% +streamline it a little bit and that's + + + align:start position:0% +streamline it a little bit and that's +actually by using uh that's actually by + + align:start position:0% +actually by using uh that's actually by + + + align:start position:0% +actually by using uh that's actually by +using weights okay so I'll come in the + + align:start position:0% +using weights okay so I'll come in the + + + align:start position:0% +using weights okay so I'll come in the +weights in this uh well not today + + align:start position:0% +weights in this uh well not today + + + align:start position:0% +weights in this uh well not today +actually but uh uh very soon all right + + align:start position:0% +actually but uh uh very soon all right + + + align:start position:0% +actually but uh uh very soon all right +so this is just a reminder of what we + + align:start position:0% +so this is just a reminder of what we + + + align:start position:0% +so this is just a reminder of what we +had we have that Yi given XI as a + + align:start position:0% +had we have that Yi given XI as a + + + align:start position:0% +had we have that Yi given XI as a +distribution distributed According to + + align:start position:0% +distribution distributed According to + + + align:start position:0% +distribution distributed According to +some distribution in the canonical + + align:start position:0% +some distribution in the canonical + + + align:start position:0% +some distribution in the canonical +exponential family so that means that + + align:start position:0% +exponential family so that means that + + + align:start position:0% +exponential family so that means that +the log likelihood looks like this again + + align:start position:0% +the log likelihood looks like this again + + + align:start position:0% +the log likelihood looks like this again +this does not matter to us this is the + + align:start position:0% +this does not matter to us this is the + + + align:start position:0% +this does not matter to us this is the +form that matters and we have a bunch of + + align:start position:0% +form that matters and we have a bunch of + + + align:start position:0% +form that matters and we have a bunch of +relationship ships that we actually + + align:start position:0% +relationship ships that we actually + + + align:start position:0% +relationship ships that we actually +spent some time Computing the first one + + align:start position:0% +spent some time Computing the first one + + + align:start position:0% +spent some time Computing the first one +is that mu is B Prime of theta I the + + align:start position:0% +is that mu is B Prime of theta I the + + + align:start position:0% +is that mu is B Prime of theta I the +second one is that if I take g g of mui + + align:start position:0% +second one is that if I take g g of mui + + + align:start position:0% +second one is that if I take g g of mui +I get this uh systematic component XI + + align:start position:0% +I get this uh systematic component XI + + + align:start position:0% +I get this uh systematic component XI +transpose beta that's modeling now if I + + align:start position:0% +transpose beta that's modeling now if I + + + align:start position:0% +transpose beta that's modeling now if I +look at the derivative mui with respect + + align:start position:0% +look at the derivative mui with respect + + + align:start position:0% +look at the derivative mui with respect +to Theta I this is the derivative of B + + align:start position:0% +to Theta I this is the derivative of B + + + align:start position:0% +to Theta I this is the derivative of B +Prime of theta I with respect to Theta I + + align:start position:0% +Prime of theta I with respect to Theta I + + + align:start position:0% +Prime of theta I with respect to Theta I +so that's the second derivative and if + + align:start position:0% +so that's the second derivative and if + + + align:start position:0% +so that's the second derivative and if +uh I'm going to call it VI if f is equal + + align:start position:0% +uh I'm going to call it VI if f is equal + + + align:start position:0% +uh I'm going to call it VI if f is equal +to one this is actually the variance and + + align:start position:0% +to one this is actually the variance and + + + align:start position:0% +to one this is actually the variance and +then I have uh this function H which + + align:start position:0% +then I have uh this function H which + + + align:start position:0% +then I have uh this function H which +allows me to bypass alog together the + + align:start position:0% +allows me to bypass alog together the + + + align:start position:0% +allows me to bypass alog together the +existence of this parameter mu which + + align:start position:0% +existence of this parameter mu which + + + align:start position:0% +existence of this parameter mu which +says if I want to go from X I transpose + + align:start position:0% +says if I want to go from X I transpose + + + align:start position:0% +says if I want to go from X I transpose +beta all the way to Theta I I have to + + align:start position:0% +beta all the way to Theta I I have to + + + align:start position:0% +beta all the way to Theta I I have to +first do G inverse and then B Prime + + align:start position:0% +first do G inverse and then B Prime + + + align:start position:0% +first do G inverse and then B Prime +inverse if I stopped here I would just + + align:start position:0% +inverse if I stopped here I would just + + + align:start position:0% +inverse if I stopped here I would just +have me + + align:start position:0% + + + + align:start position:0% + +okay okay so now if I uh what I'm going + + align:start position:0% +okay okay so now if I uh what I'm going + + + align:start position:0% +okay okay so now if I uh what I'm going +to do is I'm going to apply the chain + + align:start position:0% +to do is I'm going to apply the chain + + + align:start position:0% +to do is I'm going to apply the chain +Rule and I'm going to try to uh compute + + align:start position:0% +Rule and I'm going to try to uh compute + + + align:start position:0% +Rule and I'm going to try to uh compute +the derivative of my likelihood log + + align:start position:0% +the derivative of my likelihood log + + + align:start position:0% +the derivative of my likelihood log +likelihood with respect to to Beta so + + align:start position:0% +likelihood with respect to to Beta so + + + align:start position:0% +likelihood with respect to to Beta so +again the the log likelihood is much + + align:start position:0% +again the the log likelihood is much + + + align:start position:0% +again the the log likelihood is much +nicer when I write it as a function of + + align:start position:0% +nicer when I write it as a function of + + + align:start position:0% +nicer when I write it as a function of +theta than a function of beta but it's + + align:start position:0% +theta than a function of beta but it's + + + align:start position:0% +theta than a function of beta but it's +basically what we've been doing by hand + + align:start position:0% +basically what we've been doing by hand + + + align:start position:0% +basically what we've been doing by hand +you can write it as a derivative with + + align:start position:0% +you can write it as a derivative with + + + align:start position:0% +you can write it as a derivative with +respect to Theta first and then multiply + + align:start position:0% +respect to Theta first and then multiply + + + align:start position:0% +respect to Theta first and then multiply +by the derivative of theta with respect + + align:start position:0% +by the derivative of theta with respect + + + align:start position:0% +by the derivative of theta with respect +to Beta okay and we know that Theta + + align:start position:0% +to Beta okay and we know that Theta + + + align:start position:0% +to Beta okay and we know that Theta +depends on beta as h of X I transpose + + align:start position:0% +depends on beta as h of X I transpose + + + align:start position:0% +depends on beta as h of X I transpose +beta okay I mean that's basically what + + align:start position:0% +beta okay I mean that's basically what + + + align:start position:0% +beta okay I mean that's basically what +we've been doing for the the burnly case + + align:start position:0% +we've been doing for the the burnly case + + + align:start position:0% +we've been doing for the the burnly case +which is + + align:start position:0% +which is + + + align:start position:0% +which is +I mean we use the chain rule without + + align:start position:0% +I mean we use the chain rule without + + + align:start position:0% +I mean we use the chain rule without +actually saying it but this is going to + + align:start position:0% +actually saying it but this is going to + + + align:start position:0% +actually saying it but this is going to +be convenient to actually make it + + align:start position:0% +be convenient to actually make it + + + align:start position:0% +be convenient to actually make it +explicitly show up okay so when I first + + align:start position:0% +explicitly show up okay so when I first + + + align:start position:0% +explicitly show up okay so when I first +take the derivative of my log likelihood + + align:start position:0% +take the derivative of my log likelihood + + + align:start position:0% +take the derivative of my log likelihood +with respect to Theta I'm going to use + + align:start position:0% +with respect to Theta I'm going to use + + + align:start position:0% +with respect to Theta I'm going to use +the fact that my canonical family is + + align:start position:0% +the fact that my canonical family is + + + align:start position:0% +the fact that my canonical family is +super simple okay so what I have is that + + align:start position:0% +super simple okay so what I have is that + + + align:start position:0% +super simple okay so what I have is that +my log + + align:start position:0% +my log + + + align:start position:0% +my log +likelihood l + + align:start position:0% +likelihood l + + + align:start position:0% +likelihood l +n is the sum from I = 1 to n of y i + + align:start position:0% +n is the sum from I = 1 to n of y i + + + align:start position:0% +n is the sum from I = 1 to n of y i +Theta IUS B + + align:start position:0% +Theta IUS B + + + align:start position:0% +Theta IUS B +of theta I / f plus some constant which + + align:start position:0% +of theta I / f plus some constant which + + + align:start position:0% +of theta I / f plus some constant which +I will will go away as soon as I'm going + + align:start position:0% +I will will go away as soon as I'm going + + + align:start position:0% +I will will go away as soon as I'm going +to take my first derivative so if I take + + align:start position:0% +to take my first derivative so if I take + + + align:start position:0% +to take my first derivative so if I take +the derivative with respect to Theta + + align:start position:0% +the derivative with respect to Theta + + + align:start position:0% +the derivative with respect to Theta +I uh of this guy this is actually going + + align:start position:0% +I uh of this guy this is actually going + + + align:start position:0% +I uh of this guy this is actually going +to be equal to y i minus B Prime Theta + + align:start position:0% +to be equal to y i minus B Prime Theta + + + align:start position:0% +to be equal to y i minus B Prime Theta +I divided + + align:start position:0% +I divided + + + align:start position:0% +I divided +by and then I need to multiply with the + + align:start position:0% +by and then I need to multiply with the + + + align:start position:0% +by and then I need to multiply with the +by the derivative of theta I with + + align:start position:0% +by the derivative of theta I with + + + align:start position:0% +by the derivative of theta I with +respect to Beta And remember Theta is H + + align:start position:0% +respect to Beta And remember Theta is H + + + align:start position:0% +respect to Beta And remember Theta is H +of X I transpose beta so the derivative + + align:start position:0% +of X I transpose beta so the derivative + + + align:start position:0% +of X I transpose beta so the derivative +of theta I with respect to Beta + + align:start position:0% +of theta I with respect to Beta + + + align:start position:0% +of theta I with respect to Beta +J this is equal to H Prime of X I + + align:start position:0% +J this is equal to H Prime of X I + + + align:start position:0% +J this is equal to H Prime of X I +transpose beta and then I have uh the + + align:start position:0% +transpose beta and then I have uh the + + + align:start position:0% +transpose beta and then I have uh the +derivative of this guy actually let me + + align:start position:0% +derivative of this guy actually let me + + + align:start position:0% +derivative of this guy actually let me +just do the + + align:start position:0% + + + + align:start position:0% + +gradients of theta I at beta + + align:start position:0% +gradients of theta I at beta + + + align:start position:0% +gradients of theta I at beta +right that's what we did and just + + align:start position:0% +right that's what we did and just + + + align:start position:0% +right that's what we did and just +calling Theta I I'm just thinking of + + align:start position:0% +calling Theta I I'm just thinking of + + + align:start position:0% +calling Theta I I'm just thinking of +theta I as being a function of theta so + + align:start position:0% +theta I as being a function of theta so + + + align:start position:0% +theta I as being a function of theta so +what should I add here + + align:start position:0% +what should I add here + + + align:start position:0% +what should I add here +was just the vector + + align:start position:0% +was just the vector + + + align:start position:0% +was just the vector +XI which is just the chinal + + align:start position:0% +XI which is just the chinal + + + align:start position:0% +XI which is just the chinal +again that's H Prime right so we don't + + align:start position:0% +again that's H Prime right so we don't + + + align:start position:0% +again that's H Prime right so we don't +see it but there's a prime here it's + + align:start position:0% +see it but there's a prime here it's + + + align:start position:0% +see it but there's a prime here it's +derivative okay we've done that without + + align:start position:0% +derivative okay we've done that without + + + align:start position:0% +derivative okay we've done that without +saying it + + align:start position:0% +saying it + + + align:start position:0% +saying it +explicitly so now if I multiply those + + align:start position:0% +explicitly so now if I multiply those + + + align:start position:0% +explicitly so now if I multiply those +two things I have this Yi minus B Prime + + align:start position:0% +two things I have this Yi minus B Prime + + + align:start position:0% +two things I have this Yi minus B Prime +of theta I which I call by its good name + + align:start position:0% +of theta I which I call by its good name + + + align:start position:0% +of theta I which I call by its good name +which is + + align:start position:0% +which is + + + align:start position:0% +which is +mui right B Prime of the I is the + + align:start position:0% +mui right B Prime of the I is the + + + align:start position:0% +mui right B Prime of the I is the +expectation of Yi conditionally on XI + + align:start position:0% +expectation of Yi conditionally on XI + + + align:start position:0% +expectation of Yi conditionally on XI +and then I multiply by this thing here + + align:start position:0% +and then I multiply by this thing here + + + align:start position:0% +and then I multiply by this thing here +so here this thing is written coordinate + + align:start position:0% +so here this thing is written coordinate + + + align:start position:0% +so here this thing is written coordinate +by coordinate but I can write it as a + + align:start position:0% +by coordinate but I can write it as a + + + align:start position:0% +by coordinate but I can write it as a +big uh Vector when I stack them + + align:start position:0% +big uh Vector when I stack them + + + align:start position:0% +big uh Vector when I stack them +together and so what I claim is that + + align:start position:0% +together and so what I claim is that + + + align:start position:0% +together and so what I claim is that +this thing here is of the form y minus + + align:start position:0% +this thing here is of the form y minus + + + align:start position:0% +this thing here is of the form y minus +mu but here I put some tildas because + + align:start position:0% +mu but here I put some tildas because + + + align:start position:0% +mu but here I put some tildas because +what I did is that I first I um I uh uh + + align:start position:0% +what I did is that I first I um I uh uh + + + align:start position:0% +what I did is that I first I um I uh uh +divided this I multiply everything by G + + align:start position:0% +divided this I multiply everything by G + + + align:start position:0% +divided this I multiply everything by G +Prime of + + align:start position:0% +Prime of + + + align:start position:0% +Prime of +me for each me okay so why not okay so I + + align:start position:0% +me for each me okay so why not okay so I + + + align:start position:0% +me for each me okay so why not okay so I +uh actually on this slide it will make + + align:start position:0% +uh actually on this slide it will make + + + align:start position:0% +uh actually on this slide it will make +no sense why I do this right I basically + + align:start position:0% +no sense why I do this right I basically + + + align:start position:0% +no sense why I do this right I basically +multiply by G Prime on one side and + + align:start position:0% +multiply by G Prime on one side and + + + align:start position:0% +multiply by G Prime on one side and +divide by G Prime on the other side okay + + align:start position:0% +divide by G Prime on the other side okay + + + align:start position:0% +divide by G Prime on the other side okay +so what I write so far is that the the + + align:start position:0% +so what I write so far is that the the + + + align:start position:0% +so what I write so far is that the the +gradient of Ln sorry the gradient of Ln + + align:start position:0% +gradient of Ln sorry the gradient of Ln + + + align:start position:0% +gradient of Ln sorry the gradient of Ln +with respect to Beta is the + + align:start position:0% +with respect to Beta is the + + + align:start position:0% +with respect to Beta is the +sum from I = 1 to n of y i minus mui + + align:start position:0% +sum from I = 1 to n of y i minus mui + + + align:start position:0% +sum from I = 1 to n of y i minus mui +let's call it divided 5 times H Prime of + + align:start position:0% +let's call it divided 5 times H Prime of + + + align:start position:0% +let's call it divided 5 times H Prime of +X I transpose beta x i okay so I just + + align:start position:0% +X I transpose beta x i okay so I just + + + align:start position:0% +X I transpose beta x i okay so I just +stacked everything that's here and now + + align:start position:0% +stacked everything that's here and now + + + align:start position:0% +stacked everything that's here and now +I'm going to start calling things the + + align:start position:0% +I'm going to start calling things the + + + align:start position:0% +I'm going to start calling things the +first thing I'm going to do is I'm going + + align:start position:0% +first thing I'm going to do is I'm going + + + align:start position:0% +first thing I'm going to do is I'm going +to divide so this guy here I'm going to + + align:start position:0% +to divide so this guy here I'm going to + + + align:start position:0% +to divide so this guy here I'm going to +push + + align:start position:0% +push + + + align:start position:0% +push +here now this guy here I'm actually + + align:start position:0% +here now this guy here I'm actually + + + align:start position:0% +here now this guy here I'm actually +going to multiply by G + + align:start position:0% +going to multiply by G + + + align:start position:0% +going to multiply by G +Prime of + + align:start position:0% +Prime of + + + align:start position:0% +Prime of +mui and this guy I'm going to divide by + + align:start position:0% +mui and this guy I'm going to divide by + + + align:start position:0% +mui and this guy I'm going to divide by +G Prime of mui so there's really nothing + + align:start position:0% +G Prime of mui so there's really nothing + + + align:start position:0% +G Prime of mui so there's really nothing +that happened here I just took took G + + align:start position:0% +that happened here I just took took G + + + align:start position:0% +that happened here I just took took G +Prime and multiply and divide it by G + + align:start position:0% +Prime and multiply and divide it by G + + + align:start position:0% +Prime and multiply and divide it by G +Prime why do I do this well that's + + align:start position:0% +Prime why do I do this well that's + + + align:start position:0% +Prime why do I do this well that's +actually going to be clear when we talk + + align:start position:0% +actually going to be clear when we talk + + + align:start position:0% +actually going to be clear when we talk +about um iteratively Reed Le squares but + + align:start position:0% +about um iteratively Reed Le squares but + + + align:start position:0% +about um iteratively Reed Le squares but +now essentially I have a new mu a new Y + + align:start position:0% +now essentially I have a new mu a new Y + + + align:start position:0% +now essentially I have a new mu a new Y +which is so this thing now is going to + + align:start position:0% +which is so this thing now is going to + + + align:start position:0% +which is so this thing now is going to +be y Tilda minus + + align:start position:0% +be y Tilda minus + + + align:start position:0% +be y Tilda minus +mulda so I + + align:start position:0% +mulda so I + + + align:start position:0% +mulda so I +I now this guy + + align:start position:0% +I now this guy + + + align:start position:0% +I now this guy +here I'm going to call WI + + align:start position:0% + + + + align:start position:0% + +and uh and uh I have the XI that's there + + align:start position:0% +and uh and uh I have the XI that's there + + + align:start position:0% +and uh and uh I have the XI that's there +which means that now the thing that I + + align:start position:0% +which means that now the thing that I + + + align:start position:0% +which means that now the thing that I +have + + align:start position:0% + + + + align:start position:0% + +here I can write as + + align:start position:0% +here I can write as + + + align:start position:0% +here I can write as +follows + + align:start position:0% +follows + + + align:start position:0% +follows +gradient + + align:start position:0% +gradient + + + align:start position:0% +gradient +Ln of beta is equal to what well I'm + + align:start position:0% +Ln of beta is equal to what well I'm + + + align:start position:0% +Ln of beta is equal to what well I'm +going to write it in Matrix + + align:start position:0% +going to write it in Matrix + + + align:start position:0% +going to write it in Matrix +forms so I have the sum over I of + + align:start position:0% +forms so I have the sum over I of + + + align:start position:0% +forms so I have the sum over I of +something multipli by x i so I'm going + + align:start position:0% +something multipli by x i so I'm going + + + align:start position:0% +something multipli by x i so I'm going +to write it as X + + align:start position:0% +to write it as X + + + align:start position:0% +to write it as X +transpose then I'm going to have this + + align:start position:0% +transpose then I'm going to have this + + + align:start position:0% +transpose then I'm going to have this +Matrix + + align:start position:0% +Matrix + + + align:start position:0% +Matrix +W1 w n and then zero + + align:start position:0% +W1 w n and then zero + + + align:start position:0% +W1 w n and then zero +elsewhere and then I'm going to have my + + align:start position:0% +elsewhere and then I'm going to have my + + + align:start position:0% +elsewhere and then I'm going to have my +yelda minus mu and remember + + align:start position:0% + + + + align:start position:0% + +X is the Matrix with uh sorry it should + + align:start position:0% +X is the Matrix with uh sorry it should + + + align:start position:0% +X is the Matrix with uh sorry it should +be a bit narrow I have n and then p and + + align:start position:0% +be a bit narrow I have n and then p and + + + align:start position:0% +be a bit narrow I have n and then p and +here I have my x i j in this Matrix on + + align:start position:0% +here I have my x i j in this Matrix on + + + align:start position:0% +here I have my x i j in this Matrix on +row I and column J + + align:start position:0% +row I and column J + + + align:start position:0% +row I and column J +J and uh this is just the Matrix that + + align:start position:0% +J and uh this is just the Matrix that + + + align:start position:0% +J and uh this is just the Matrix that +has the W eyes on the diagonal and then + + align:start position:0% +has the W eyes on the diagonal and then + + + align:start position:0% +has the W eyes on the diagonal and then +I have whitea minus me so this is just + + align:start position:0% +I have whitea minus me so this is just + + + align:start position:0% +I have whitea minus me so this is just +the Matrix rewriting of this formula all + + align:start position:0% +the Matrix rewriting of this formula all + + + align:start position:0% +the Matrix rewriting of this formula all +right so it's just saying that if I look + + align:start position:0% +right so it's just saying that if I look + + + align:start position:0% +right so it's just saying that if I look +at the sum of weighted things of my + + align:start position:0% +at the sum of weighted things of my + + + align:start position:0% +at the sum of weighted things of my +colums of XI it's basically the same + + align:start position:0% +colums of XI it's basically the same + + + align:start position:0% +colums of XI it's basically the same +thing right when I'm going to multiply + + align:start position:0% +thing right when I'm going to multiply + + + align:start position:0% +thing right when I'm going to multiply +this by my Matrix I'm going to get + + align:start position:0% +this by my Matrix I'm going to get + + + align:start position:0% +this by my Matrix I'm going to get +exactly those terms right y i minus mui + + align:start position:0% +exactly those terms right y i minus mui + + + align:start position:0% +exactly those terms right y i minus mui +telda time w i and then when I actually + + align:start position:0% +telda time w i and then when I actually + + + align:start position:0% +telda time w i and then when I actually +take this X I transpose time this guy + + align:start position:0% +take this X I transpose time this guy + + + align:start position:0% +take this X I transpose time this guy +I'm really just getting the sum of the + + align:start position:0% +I'm really just getting the sum of the + + + align:start position:0% +I'm really just getting the sum of the +columns uh uh with + + align:start position:0% +columns uh uh with + + + align:start position:0% +columns uh uh with +the with the weights right agree so if I + + align:start position:0% +the with the weights right agree so if I + + + align:start position:0% +the with the weights right agree so if I +look at this thing here this is a vector + + align:start position:0% +look at this thing here this is a vector + + + align:start position:0% +look at this thing here this is a vector +that has s + + align:start position:0% +that has s + + + align:start position:0% +that has s +coordinate y i w i * yielda minus mu + + align:start position:0% +coordinate y i w i * yielda minus mu + + + align:start position:0% +coordinate y i w i * yielda minus mu +IA and I have n of them so when I + + align:start position:0% +IA and I have n of them so when I + + + align:start position:0% +IA and I have n of them so when I +multiply X transpose by this guy I'm + + align:start position:0% +multiply X transpose by this guy I'm + + + align:start position:0% +multiply X transpose by this guy I'm +just looking at a weighted sum of The + + align:start position:0% +just looking at a weighted sum of The + + + align:start position:0% +just looking at a weighted sum of The +Columns of X transpose which is a + + align:start position:0% +Columns of X transpose which is a + + + align:start position:0% +Columns of X transpose which is a +weighted sum of the rows of X which are + + align:start position:0% +weighted sum of the rows of X which are + + + align:start position:0% +weighted sum of the rows of X which are +exactly my x + + align:start position:0% +exactly my x + + + align:start position:0% +exactly my x +i right and that's this weed Su of the + + align:start position:0% + + + + align:start position:0% + +XI okay so here as I said the fact that + + align:start position:0% +XI okay so here as I said the fact that + + + align:start position:0% +XI okay so here as I said the fact that +we decided to put this G Prime of mui + + align:start position:0% +we decided to put this G Prime of mui + + + align:start position:0% +we decided to put this G Prime of mui +here and G Prime of mui here we could + + align:start position:0% +here and G Prime of mui here we could + + + align:start position:0% +here and G Prime of mui here we could +have not done this right we could have + + align:start position:0% +have not done this right we could have + + + align:start position:0% +have not done this right we could have +just said this I call I don't even for I + + align:start position:0% +just said this I call I don't even for I + + + align:start position:0% +just said this I call I don't even for I +forget about the T I just call it y i + + align:start position:0% +forget about the T I just call it y i + + + align:start position:0% +forget about the T I just call it y i +minus mui and here I just put everything + + align:start position:0% +minus mui and here I just put everything + + + align:start position:0% +minus mui and here I just put everything +I don't know into some W and so why do I + + align:start position:0% +I don't know into some W and so why do I + + + align:start position:0% +I don't know into some W and so why do I +do this well it's because when I + + align:start position:0% +do this well it's because when I + + + align:start position:0% +do this well it's because when I +actually start looking at the + + align:start position:0% +actually start looking at the + + + align:start position:0% +actually start looking at the +hashen what's going to + + align:start position:0% +hashen what's going to + + + align:start position:0% +hashen what's going to +happen uh yeah we'll do that next time + + align:start position:0% +happen uh yeah we'll do that next time + + + align:start position:0% +happen uh yeah we'll do that next time +but uh let's just look quickly at the + + align:start position:0% +but uh let's just look quickly at the + + + align:start position:0% +but uh let's just look quickly at the +outcome of the computation of my + + align:start position:0% +outcome of the computation of my + + + align:start position:0% +outcome of the computation of my +Hasen so I compute a bunch of second + + align:start position:0% +Hasen so I compute a bunch of second + + + align:start position:0% +Hasen so I compute a bunch of second +derivatives and here I have two terms + + align:start position:0% +derivatives and here I have two terms + + + align:start position:0% +derivatives and here I have two terms +right well he's gone right so I have two + + align:start position:0% +right well he's gone right so I have two + + + align:start position:0% +right well he's gone right so I have two +terms and when I take the uh expectation + + align:start position:0% +terms and when I take the uh expectation + + + align:start position:0% +terms and when I take the uh expectation +now it's G to actually change right this + + align:start position:0% +now it's G to actually change right this + + + align:start position:0% +now it's G to actually change right this +thing is actually going to depend on Yi + + align:start position:0% +thing is actually going to depend on Yi + + + align:start position:0% +thing is actually going to depend on Yi +because I have an H which is not the + + align:start position:0% +because I have an H which is not the + + + align:start position:0% +because I have an H which is not the +identity Oh no you're here sorry and uh + + align:start position:0% +identity Oh no you're here sorry and uh + + + align:start position:0% +identity Oh no you're here sorry and uh +so when I start looking at the + + align:start position:0% +so when I start looking at the + + + align:start position:0% +so when I start looking at the +expectation so I look at the conditional + + align:start position:0% +expectation so I look at the conditional + + + align:start position:0% +expectation so I look at the conditional +expectation given XI the first term here + + align:start position:0% +expectation given XI the first term here + + + align:start position:0% +expectation given XI the first term here +has a Yi minus its + + align:start position:0% +has a Yi minus its + + + align:start position:0% +has a Yi minus its +expectation so when I take the + + align:start position:0% +expectation so when I take the + + + align:start position:0% +expectation so when I take the +conditional expectation this is going to + + align:start position:0% +conditional expectation this is going to + + + align:start position:0% +conditional expectation this is going to +be zero the first term is going away + + align:start position:0% +be zero the first term is going away + + + align:start position:0% +be zero the first term is going away +when I take the conditional expectation + + align:start position:0% +when I take the conditional expectation + + + align:start position:0% +when I take the conditional expectation +but this was actually gone already if we + + align:start position:0% +but this was actually gone already if we + + + align:start position:0% +but this was actually gone already if we +had the iCal term because the second + + align:start position:0% +had the iCal term because the second + + + align:start position:0% +had the iCal term because the second +derivative of H when H is the identity + + align:start position:0% +derivative of H when H is the identity + + + align:start position:0% +derivative of H when H is the identity +is zero but if H is not the identity H + + align:start position:0% +is zero but if H is not the identity H + + + align:start position:0% +is zero but if H is not the identity H +prime prime may not be zero and so I + + align:start position:0% +prime prime may not be zero and so I + + + align:start position:0% +prime prime may not be zero and so I +need that part to remove that + + align:start position:0% +need that part to remove that + + + align:start position:0% +need that part to remove that +term and so now you know I work a little + + align:start position:0% +term and so now you know I work a little + + + align:start position:0% +term and so now you know I work a little +bit and I get this term it's not very + + align:start position:0% +bit and I get this term it's not very + + + align:start position:0% +bit and I get this term it's not very +surprising in the second derivative I + + align:start position:0% +surprising in the second derivative I + + + align:start position:0% +surprising in the second derivative I +see I have terms in B prime prime I have + + align:start position:0% +see I have terms in B prime prime I have + + + align:start position:0% +see I have terms in B prime prime I have +term in h Prime but square and then I + + align:start position:0% +term in h Prime but square and then I + + + align:start position:0% +term in h Prime but square and then I +have my XI outer XI X ixi transpose + + align:start position:0% +have my XI outer XI X ixi transpose + + + align:start position:0% +have my XI outer XI X ixi transpose +which we know we would see okay so we'll + + align:start position:0% +which we know we would see okay so we'll + + + align:start position:0% +which we know we would see okay so we'll +go through those things next time but + + align:start position:0% +go through those things next time but + + + align:start position:0% +go through those things next time but +what I wanted to show you is that now uh + + align:start position:0% +what I wanted to show you is that now uh + + + align:start position:0% +what I wanted to show you is that now uh +once I compute + + align:start position:0% +once I compute + + + align:start position:0% +once I compute +this uh I can actually show that if I + + align:start position:0% +this uh I can actually show that if I + + + align:start position:0% +this uh I can actually show that if I +look at this product that showed up + + align:start position:0% +look at this product that showed up + + + align:start position:0% +look at this product that showed up +right I had B prime prime time H H Prime + + align:start position:0% +right I had B prime prime time H H Prime + + + align:start position:0% +right I had B prime prime time H H Prime +squared one of those terms is actually + + align:start position:0% +squared one of those terms is actually + + + align:start position:0% +squared one of those terms is actually +one over G + + align:start position:0% +one over G + + + align:start position:0% +one over G +Prime and so I can rewrite it as one of + + align:start position:0% +Prime and so I can rewrite it as one of + + + align:start position:0% +Prime and so I can rewrite it as one of +the H primes because I had a square + + align:start position:0% +the H primes because I had a square + + + align:start position:0% +the H primes because I had a square +divided by G Prime and now I have this + + align:start position:0% +divided by G Prime and now I have this + + + align:start position:0% +divided by G Prime and now I have this +XI XI transpose so if I did not put the + + align:start position:0% +XI XI transpose so if I did not put the + + + align:start position:0% +XI XI transpose so if I did not put the +if I did not put the G Prime in the W + + align:start position:0% +if I did not put the G Prime in the W + + + align:start position:0% +if I did not put the G Prime in the W +that I put here completely artificially + + align:start position:0% +that I put here completely artificially + + + align:start position:0% +that I put here completely artificially +I would not be able to call this guy + + align:start position:0% +I would not be able to call this guy + + + align:start position:0% +I would not be able to call this guy +W which is exactly what it is from this + + align:start position:0% +W which is exactly what it is from this + + + align:start position:0% +W which is exactly what it is from this +board and now that this guy is w I can + + align:start position:0% +board and now that this guy is w I can + + + align:start position:0% +board and now that this guy is w I can +actually write this thing here as X + + align:start position:0% +actually write this thing here as X + + + align:start position:0% +actually write this thing here as X +transpose + + align:start position:0% +transpose + + + align:start position:0% +transpose +WX okay and that's why I really wanted + + align:start position:0% +WX okay and that's why I really wanted + + + align:start position:0% +WX okay and that's why I really wanted +my w to have this G Prime of mui in the + + align:start position:0% +my w to have this G Prime of mui in the + + + align:start position:0% +my w to have this G Prime of mui in the +denominator because now I can actually + + align:start position:0% +denominator because now I can actually + + + align:start position:0% +denominator because now I can actually +write a term that depends on W now you + + align:start position:0% +write a term that depends on W now you + + + align:start position:0% +write a term that depends on W now you +might say how do I reconcile those two + + align:start position:0% +might say how do I reconcile those two + + + align:start position:0% +might say how do I reconcile those two +things what the hell are you doing and + + align:start position:0% +things what the hell are you doing and + + + align:start position:0% +things what the hell are you doing and +the what the hell I'm doing is + + align:start position:0% +the what the hell I'm doing is + + + align:start position:0% +the what the hell I'm doing is +essentially that I'm saying that if you + + align:start position:0% +essentially that I'm saying that if you + + + align:start position:0% +essentially that I'm saying that if you +write beta + + align:start position:0% +write beta + + + align:start position:0% +write beta +K according to the Fisher scoring + + align:start position:0% +K according to the Fisher scoring + + + align:start position:0% +K according to the Fisher scoring +iterations you can actually write it as + + align:start position:0% +iterations you can actually write it as + + + align:start position:0% +iterations you can actually write it as +just this term here which is of the form + + align:start position:0% +just this term here which is of the form + + + align:start position:0% +just this term here which is of the form +X transpose X inverse X transpose y but + + align:start position:0% +X transpose X inverse X transpose y but + + + align:start position:0% +X transpose X inverse X transpose y but +where I actually squeezed in this + + align:start position:0% +where I actually squeezed in this + + + align:start position:0% +where I actually squeezed in this +W's and that's actually a weighted Le + + align:start position:0% +W's and that's actually a weighted Le + + + align:start position:0% +W's and that's actually a weighted Le +squares and it's applied to this + + align:start position:0% +squares and it's applied to this + + + align:start position:0% +squares and it's applied to this +particular guy so we'll talk about those + + align:start position:0% +particular guy so we'll talk about those + + + align:start position:0% +particular guy so we'll talk about those +weighted Le squares but remember Le + + align:start position:0% +weighted Le squares but remember Le + + + align:start position:0% +weighted Le squares but remember Le +squares is of the form X beta hat is X + + align:start position:0% +squares is of the form X beta hat is X + + + align:start position:0% +squares is of the form X beta hat is X +transpose X inverse X transpose Y and + + align:start position:0% +transpose X inverse X transpose Y and + + + align:start position:0% +transpose X inverse X transpose Y and +here is basically the same thing except + + align:start position:0% +here is basically the same thing except + + + align:start position:0% +here is basically the same thing except +that I squeeze in some W after my X + + align:start position:0% +that I squeeze in some W after my X + + + align:start position:0% +that I squeeze in some W after my X +transpose okay so that's how we're going + + align:start position:0% +transpose okay so that's how we're going + + + align:start position:0% +transpose okay so that's how we're going +to solve uh I don't want to go into the + + align:start position:0% +to solve uh I don't want to go into the + + + align:start position:0% +to solve uh I don't want to go into the +details now and uh because mostly + + align:start position:0% +details now and uh because mostly + + + align:start position:0% +details now and uh because mostly +because we're running out of time are + + align:start position:0% +because we're running out of time are + + + align:start position:0% +because we're running out of time are +there any questions \ No newline at end of file diff --git a/OgGTJIgNewE.txt b/OgGTJIgNewE.txt new file mode 100644 index 0000000000000000000000000000000000000000..eae7cb2e5c0c0f3d3b53d2d1bfdcab3143d7489b --- /dev/null +++ b/OgGTJIgNewE.txt @@ -0,0 +1,15120 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT open courseware continue + + align:start position:0% +will help MIT open courseware continue + + + align:start position:0% +will help MIT open courseware continue +to offer highquality educational + + align:start position:0% +to offer highquality educational + + + align:start position:0% +to offer highquality educational +resources for free to make a donation or + + align:start position:0% +resources for free to make a donation or + + + align:start position:0% +resources for free to make a donation or +to view additional materials from + + align:start position:0% +to view additional materials from + + + align:start position:0% +to view additional materials from +hundreds of MIT courses visit MIT + + align:start position:0% +hundreds of MIT courses visit MIT + + + align:start position:0% +hundreds of MIT courses visit MIT +opencourseware at + + align:start position:0% + + + + align:start position:0% + +ocw.mit.edu all right guys let's uh get + + align:start position:0% +ocw.mit.edu all right guys let's uh get + + + align:start position:0% +ocw.mit.edu all right guys let's uh get +started so today we're going to talk + + align:start position:0% +started so today we're going to talk + + + align:start position:0% +started so today we're going to talk +about tour and we actually have one of + + align:start position:0% +about tour and we actually have one of + + + align:start position:0% +about tour and we actually have one of +the authors of the paper you guys read + + align:start position:0% +the authors of the paper you guys read + + + align:start position:0% +the authors of the paper you guys read +for today uh Nick Matthew he's also one + + align:start position:0% +for today uh Nick Matthew he's also one + + + align:start position:0% +for today uh Nick Matthew he's also one +of the main developers of tour he's + + align:start position:0% +of the main developers of tour he's + + + align:start position:0% +of the main developers of tour he's +going to tell you more about it thank + + align:start position:0% +going to tell you more about it thank + + + align:start position:0% +going to tell you more about it thank +you um so at this point I could start + + align:start position:0% +you um so at this point I could start + + + align:start position:0% +you um so at this point I could start +out by saying please put your hand dos + + align:start position:0% +out by saying please put your hand dos + + + align:start position:0% +out by saying please put your hand dos +up if you didn't read the paper but that + + align:start position:0% +up if you didn't read the paper but that + + + align:start position:0% +up if you didn't read the paper but that +wouldn't work because it's embarrassing + + align:start position:0% +wouldn't work because it's embarrassing + + + align:start position:0% +wouldn't work because it's embarrassing +not to have read a paper you're supposed + + align:start position:0% +not to have read a paper you're supposed + + + align:start position:0% +not to have read a paper you're supposed +to to have read so instead what I will + + align:start position:0% +to to have read so instead what I will + + + align:start position:0% +to to have read so instead what I will +ask is think of your birthday think of + + align:start position:0% +ask is think of your birthday think of + + + align:start position:0% +ask is think of your birthday think of +the date of your birth if the last digit + + align:start position:0% +the date of your birth if the last digit + + + align:start position:0% +the date of your birth if the last digit +of the date of your birth is mod or you + + align:start position:0% +of the date of your birth is mod or you + + + align:start position:0% +of the date of your birth is mod or you +didn't read the paper please raise your + + align:start position:0% + + + + align:start position:0% + +hand okay that's not far from half so + + align:start position:0% +hand okay that's not far from half so + + + align:start position:0% +hand okay that's not far from half so +I'm guessing most people read the + + align:start position:0% + + + + align:start position:0% + +paper means of + + align:start position:0% +paper means of + + + align:start position:0% +paper means of +communicating that preserve our privacy + + align:start position:0% +communicating that preserve our privacy + + + align:start position:0% +communicating that preserve our privacy +enable to us to communicate more + + align:start position:0% +enable to us to communicate more + + + align:start position:0% +enable to us to communicate more +honestly to gather better information + + align:start position:0% +honestly to gather better information + + + align:start position:0% +honestly to gather better information +about the world when we are less + + align:start position:0% +about the world when we are less + + + align:start position:0% +about the world when we are less +disinhibited from speaking because of of + + align:start position:0% +disinhibited from speaking because of of + + + align:start position:0% +disinhibited from speaking because of of +possibly Justified possibly unjustified + + align:start position:0% +possibly Justified possibly unjustified + + + align:start position:0% +possibly Justified possibly unjustified +social and other + + align:start position:0% +social and other + + + align:start position:0% +social and other +consequences so which this brings us to + + align:start position:0% +consequences so which this brings us to + + + align:start position:0% +consequences so which this brings us to +tour which is an anonymity Network that + + align:start position:0% +tour which is an anonymity Network that + + + align:start position:0% +tour which is an anonymity Network that +I've been working on for the last 10 + + align:start position:0% +I've been working on for the last 10 + + + align:start position:0% +I've been working on for the last 10 +years with some friends and colleagues + + align:start position:0% +years with some friends and colleagues + + + align:start position:0% +years with some friends and colleagues +and so on um General overview there + + align:start position:0% +and so on um General overview there + + + align:start position:0% +and so on um General overview there +there's a set of volunteer operated + + align:start position:0% +there's a set of volunteer operated + + + align:start position:0% +there's a set of volunteer operated +servers about 6,000 of them at first it + + align:start position:0% +servers about 6,000 of them at first it + + + align:start position:0% +servers about 6,000 of them at first it +was just um friends of ours that we knew + + align:start position:0% +was just um friends of ours that we knew + + + align:start position:0% +was just um friends of ours that we knew +from that Roger dingledine and I knew + + align:start position:0% +from that Roger dingledine and I knew + + + align:start position:0% +from that Roger dingledine and I knew +from MIT after that um + + align:start position:0% +from MIT after that um + + + align:start position:0% +from MIT after that um +we we got more publicity more people + + align:start position:0% +we we got more publicity more people + + + align:start position:0% +we we got more publicity more people +started running servers we now it's run + + align:start position:0% +started running servers we now it's run + + + align:start position:0% +started running servers we now it's run +by nonprofits private individuals some + + align:start position:0% +by nonprofits private individuals some + + + align:start position:0% +by nonprofits private individuals some +University teams possibly some of you + + align:start position:0% +University teams possibly some of you + + + align:start position:0% +University teams possibly some of you +here today + + align:start position:0% +here today + + + align:start position:0% +here today +and and no doubt some very sketchy + + align:start position:0% +and and no doubt some very sketchy + + + align:start position:0% +and and no doubt some very sketchy +people we're serving we got about 6,000 + + align:start position:0% +people we're serving we got about 6,000 + + + align:start position:0% +people we're serving we got about 6,000 +nodes we're serving on the order of + + align:start position:0% +nodes we're serving on the order of + + + align:start position:0% +nodes we're serving on the order of +hundreds of thousands to millions of + + align:start position:0% +hundreds of thousands to millions of + + + align:start position:0% +hundreds of thousands to millions of +users depending on how you count it's + + align:start position:0% +users depending on how you count it's + + + align:start position:0% +users depending on how you count it's +kind of hard to count because they're + + align:start position:0% +kind of hard to count because they're + + + align:start position:0% +kind of hard to count because they're +Anonymous so you have to use statistical + + align:start position:0% +Anonymous so you have to use statistical + + + align:start position:0% +Anonymous so you have to use statistical +techniques to estimate and doing on the + + align:start position:0% +techniques to estimate and doing on the + + + align:start position:0% +techniques to estimate and doing on the +order of terabytes per second worth of + + align:start position:0% +order of terabytes per second worth of + + + align:start position:0% +order of terabytes per second worth of +traffic uh lots of people need anonymity + + align:start position:0% +traffic uh lots of people need anonymity + + + align:start position:0% +traffic uh lots of people need anonymity +for their regular work not everyone who + + align:start position:0% +for their regular work not everyone who + + + align:start position:0% +for their regular work not everyone who +needs anonymity though thinks of it as + + align:start position:0% +needs anonymity though thinks of it as + + + align:start position:0% +needs anonymity though thinks of it as +anonymity some people say um I I don't + + align:start position:0% +anonymity some people say um I I don't + + + align:start position:0% +anonymity some people say um I I don't +need anonymity I'm perfectly fine + + align:start position:0% +need anonymity I'm perfectly fine + + + align:start position:0% +need anonymity I'm perfectly fine +identifying myself but there's broad + + align:start position:0% +identifying myself but there's broad + + + align:start position:0% +identifying myself but there's broad +perceptions though that + + align:start position:0% +perceptions though that + + + align:start position:0% +perceptions though that +privacy is necessary or useful and when + + align:start position:0% +privacy is necessary or useful and when + + + align:start position:0% +privacy is necessary or useful and when +regular citizens use anonymity stuff + + align:start position:0% +regular citizens use anonymity stuff + + + align:start position:0% +regular citizens use anonymity stuff +they tend to be doing it because they + + align:start position:0% +they tend to be doing it because they + + + align:start position:0% +they tend to be doing it because they +want privacy in search results privacy + + align:start position:0% +want privacy in search results privacy + + + align:start position:0% +want privacy in search results privacy +in doing research on the internet they + + align:start position:0% +in doing research on the internet they + + + align:start position:0% +in doing research on the internet they +want to be able to engage in local + + align:start position:0% +want to be able to engage in local + + + align:start position:0% +want to be able to engage in local +politics while not offending local + + align:start position:0% +politics while not offending local + + + align:start position:0% +politics while not offending local +politicians and so + + align:start position:0% +politicians and so + + + align:start position:0% +politicians and so +on researchers frequently use + + align:start position:0% +on researchers frequently use + + + align:start position:0% +on researchers frequently use +anonymizing tools to avoid Gathering + + align:start position:0% +anonymizing tools to avoid Gathering + + + align:start position:0% +anonymizing tools to avoid Gathering +biased data biased by um geolocation + + align:start position:0% +biased data biased by um geolocation + + + align:start position:0% +biased data biased by um geolocation +Based Services that might be serving + + align:start position:0% +Based Services that might be serving + + + align:start position:0% +Based Services that might be serving +them in particular different versions of + + align:start position:0% +them in particular different versions of + + + align:start position:0% +them in particular different versions of +things companies use anonymity + + align:start position:0% +things companies use anonymity + + + align:start position:0% +things companies use anonymity +Technologies for for protection of + + align:start position:0% +Technologies for for protection of + + + align:start position:0% +Technologies for for protection of +sensitive data for instance if you are + + align:start position:0% +sensitive data for instance if you are + + + align:start position:0% +sensitive data for instance if you are +if for instance if I can track all of + + align:start position:0% +if for instance if I can track all of + + + align:start position:0% +if for instance if I can track all of +the movements of the legal team for some + + align:start position:0% +the movements of the legal team for some + + + align:start position:0% +the movements of the legal team for some +major internet company I can probably + + align:start position:0% +major internet company I can probably + + + align:start position:0% +major internet company I can probably +tell a lot about um just by tracking + + align:start position:0% +tell a lot about um just by tracking + + + align:start position:0% +tell a lot about um just by tracking +when when they're visiting their their + + align:start position:0% +when when they're visiting their their + + + align:start position:0% +when when they're visiting their their +web server from different places around + + align:start position:0% +web server from different places around + + + align:start position:0% +web server from different places around +the world I can learn a lot or when + + align:start position:0% +the world I can learn a lot or when + + + align:start position:0% +the world I can learn a lot or when +they're visiting the company VPN from + + align:start position:0% +they're visiting the company VPN from + + + align:start position:0% +they're visiting the company VPN from +different places around the world I can + + align:start position:0% +different places around the world I can + + + align:start position:0% +different places around the world I can +learn a lot about which teams are + + align:start position:0% +learn a lot about which teams are + + + align:start position:0% +learn a lot about which teams are +collaborating with which and this is + + align:start position:0% +collaborating with which and this is + + + align:start position:0% +collaborating with which and this is +information companies would like to keep + + align:start position:0% +information companies would like to keep + + + align:start position:0% +information companies would like to keep +private companies also need anonymity + + align:start position:0% +private companies also need anonymity + + + align:start position:0% +private companies also need anonymity +technology for doing research + + align:start position:0% +technology for doing research + + + align:start position:0% +technology for doing research +so a major router manufacturer for some + + align:start position:0% +so a major router manufacturer for some + + + align:start position:0% +so a major router manufacturer for some +while I don't know if this is still the + + align:start position:0% +while I don't know if this is still the + + + align:start position:0% +while I don't know if this is still the +case would regularly serve different + + align:start position:0% +case would regularly serve different + + + align:start position:0% +case would regularly serve different +versions of its product sheets to IP + + align:start position:0% +versions of its product sheets to IP + + + align:start position:0% +versions of its product sheets to IP +addresses associated with its + + align:start position:0% +addresses associated with its + + + align:start position:0% +addresses associated with its +competitors in order to make reverse + + align:start position:0% +competitors in order to make reverse + + + align:start position:0% +competitors in order to make reverse +engineering + + align:start position:0% +engineering + + + align:start position:0% +engineering +trickier and they found this out by + + align:start position:0% +trickier and they found this out by + + + align:start position:0% +trickier and they found this out by +using our software and saying hey wait a + + align:start position:0% +using our software and saying hey wait a + + + align:start position:0% +using our software and saying hey wait a +minute we got a different product sheet + + align:start position:0% +minute we got a different product sheet + + + align:start position:0% +minute we got a different product sheet +when we came in from tour than we did + + align:start position:0% +when we came in from tour than we did + + + align:start position:0% +when we came in from tour than we did +coming directly and it's also kind of + + align:start position:0% +coming directly and it's also kind of + + + align:start position:0% +coming directly and it's also kind of +normal for some companies to serve other + + align:start position:0% +normal for some companies to serve other + + + align:start position:0% +normal for some companies to serve other +companies versions of their websites to + + align:start position:0% +companies versions of their websites to + + + align:start position:0% +companies versions of their websites to +emphasize the employment opportunity + + align:start position:0% +emphasize the employment opportunity + + + align:start position:0% +emphasize the employment opportunity +sections um Regular law enforcement and + + align:start position:0% +sections um Regular law enforcement and + + + align:start position:0% +sections um Regular law enforcement and +needs anonymity Technologies as well to + + align:start position:0% +needs anonymity Technologies as well to + + + align:start position:0% +needs anonymity Technologies as well to +avoid tipping off people when you're + + align:start position:0% +avoid tipping off people when you're + + + align:start position:0% +avoid tipping off people when you're +doing investigations you do not want the + + align:start position:0% +doing investigations you do not want the + + + align:start position:0% +doing investigations you do not want the +local police station to appear in the + + align:start position:0% +local police station to appear in the + + + align:start position:0% +local police station to appear in the +web logs of somebody you're + + align:start position:0% +web logs of somebody you're + + + align:start position:0% +web logs of somebody you're +investigating and regular folks need it + + align:start position:0% +investigating and regular folks need it + + + align:start position:0% +investigating and regular folks need it +I said for avoiding harassment because + + align:start position:0% +I said for avoiding harassment because + + + align:start position:0% +I said for avoiding harassment because +of online activities to research stuff + + align:start position:0% +of online activities to research stuff + + + align:start position:0% +of online activities to research stuff +that might be embarrassing if you live + + align:start position:0% +that might be embarrassing if you live + + + align:start position:0% +that might be embarrassing if you live +in a country with uncertain healthc care + + align:start position:0% +in a country with uncertain healthc care + + + align:start position:0% +in a country with uncertain healthc care +laws it's a good idea to uh you might + + align:start position:0% +laws it's a good idea to uh you might + + + align:start position:0% +laws it's a good idea to uh you might +want to avoid creating too much public + + align:start position:0% +want to avoid creating too much public + + + align:start position:0% +want to avoid creating too much public +record of what diseases you think you + + align:start position:0% +record of what diseases you think you + + + align:start position:0% +record of what diseases you think you +might have and so on or what any + + align:start position:0% +might have and so on or what any + + + align:start position:0% +might have and so on or what any +dangerous Hobbies you might + + align:start position:0% +dangerous Hobbies you might + + + align:start position:0% +dangerous Hobbies you might +have and um also lots of criminal or bad + + align:start position:0% +have and um also lots of criminal or bad + + + align:start position:0% +have and um also lots of criminal or bad +folks use anonymity technology it's not + + align:start position:0% +folks use anonymity technology it's not + + + align:start position:0% +folks use anonymity technology it's not +their only option but + + align:start position:0% +their only option but + + + align:start position:0% +their only option but +um if you are willing to purchase time + + align:start position:0% +um if you are willing to purchase time + + + align:start position:0% +um if you are willing to purchase time +on a botn net you can buy some pretty + + align:start position:0% +on a botn net you can buy some pretty + + + align:start position:0% +on a botn net you can buy some pretty +good privacy um that is not available to + + align:start position:0% +good privacy um that is not available to + + + align:start position:0% +good privacy um that is not available to +people who think that bot Nets are + + align:start position:0% +people who think that bot Nets are + + + align:start position:0% +people who think that bot Nets are +immoral and tour and anonymity stuff in + + align:start position:0% +immoral and tour and anonymity stuff in + + + align:start position:0% +immoral and tour and anonymity stuff in +general are not the only multi multi-use + + align:start position:0% +general are not the only multi multi-use + + + align:start position:0% +general are not the only multi multi-use +technology out there uh let's see the + + align:start position:0% +technology out there uh let's see the + + + align:start position:0% +technology out there uh let's see the +average under graduate is about 20 so + + align:start position:0% +average under graduate is about 20 so + + + align:start position:0% +average under graduate is about 20 so +you been around when you were born um + + align:start position:0% +you been around when you were born um + + + align:start position:0% +you been around when you were born um +there was have you talked the crypto + + align:start position:0% +there was have you talked the crypto + + + align:start position:0% +there was have you talked the crypto +Wars at all no um during the the 1990s + + align:start position:0% +Wars at all no um during the the 1990s + + + align:start position:0% +Wars at all no um during the the 1990s +it was sort of an up in theair question + + align:start position:0% +it was sort of an up in theair question + + + align:start position:0% +it was sort of an up in theair question +in the United States about to what + + align:start position:0% +in the United States about to what + + + align:start position:0% +in the United States about to what +extent crypto civilian use of non-b + + align:start position:0% +extent crypto civilian use of non-b + + + align:start position:0% +extent crypto civilian use of non-b +backdoored cryptography should be legal + + align:start position:0% +backdoored cryptography should be legal + + + align:start position:0% +backdoored cryptography should be legal +and to what extent it should be + + align:start position:0% +and to what extent it should be + + + align:start position:0% +and to what extent it should be +exported that kind of came down pretty + + align:start position:0% +exported that kind of came down pretty + + + align:start position:0% +exported that kind of came down pretty +decisively on the side of cryptography + + align:start position:0% +decisively on the side of cryptography + + + align:start position:0% +decisively on the side of cryptography +should be legal and exportable during + + align:start position:0% +should be legal and exportable during + + + align:start position:0% +should be legal and exportable during +the '90s and early + + align:start position:0% +the '90s and early + + + align:start position:0% +the '90s and early +2000s and although there's some debate + + align:start position:0% +2000s and although there's some debate + + + align:start position:0% +2000s and although there's some debate +about anonymity technology it's more or + + align:start position:0% +about anonymity technology it's more or + + + align:start position:0% +about anonymity technology it's more or +less the same + + align:start position:0% +less the same + + + align:start position:0% +less the same +debate and I think it's going to end in + + align:start position:0% +debate and I think it's going to end in + + + align:start position:0% +debate and I think it's going to end in +more or less the same way + + align:start position:0% +more or less the same way + + + align:start position:0% +more or less the same way +so here's an outline of my talk going to + + align:start position:0% +so here's an outline of my talk going to + + + align:start position:0% +so here's an outline of my talk going to +give you that little introduction I gave + + align:start position:0% +give you that little introduction I gave + + + align:start position:0% +give you that little introduction I gave +you talk a little bit about what we mean + + align:start position:0% +you talk a little bit about what we mean + + + align:start position:0% +you talk a little bit about what we mean +by anonymity in a technical sense uh + + align:start position:0% +by anonymity in a technical sense uh + + + align:start position:0% +by anonymity in a technical sense uh +talk a little about our motivations for + + align:start position:0% +talk a little about our motivations for + + + align:start position:0% +talk a little about our motivations for +getting into it then I'm going to go to + + align:start position:0% +getting into it then I'm going to go to + + + align:start position:0% +getting into it then I'm going to go to +kind of walk you through stepbystep how + + align:start position:0% +kind of walk you through stepbystep how + + + align:start position:0% +kind of walk you through stepbystep how +you start with the idea of we ought to + + align:start position:0% +you start with the idea of we ought to + + + align:start position:0% +you start with the idea of we ought to +have some anonymity and how you wind up + + align:start position:0% +have some anonymity and how you wind up + + + align:start position:0% +have some anonymity and how you wind up +with the design of Torah from that point + + align:start position:0% +with the design of Torah from that point + + + align:start position:0% +with the design of Torah from that point +and I'll mention some branching off + + align:start position:0% +and I'll mention some branching off + + + align:start position:0% +and I'll mention some branching off +points where you might wind up with + + align:start position:0% +points where you might wind up with + + + align:start position:0% +points where you might wind up with +other designs I'll pause to answer some + + align:start position:0% +other designs I'll pause to answer some + + + align:start position:0% +other designs I'll pause to answer some +of the cool questions that everyone has + + align:start position:0% +of the cool questions that everyone has + + + align:start position:0% +of the cool questions that everyone has +sent in for their class + + align:start position:0% +sent in for their class + + + align:start position:0% +sent in for their class +assignment I'll talk a little bit about + + align:start position:0% +assignment I'll talk a little bit about + + + align:start position:0% +assignment I'll talk a little bit about +how no Discovery Works which is an + + align:start position:0% +how no Discovery Works which is an + + + align:start position:0% +how no Discovery Works which is an +important topic then I'll sort of by + + align:start position:0% +important topic then I'll sort of by + + + align:start position:0% +important topic then I'll sort of by +show of hands pick which of these + + align:start position:0% +show of hands pick which of these + + + align:start position:0% +show of hands pick which of these +Advanced topics to cover I guess I'm + + align:start position:0% +Advanced topics to cover I guess I'm + + + align:start position:0% +Advanced topics to cover I guess I'm +just calling them Advanced because + + align:start position:0% +just calling them Advanced because + + + align:start position:0% +just calling them Advanced because +they're later in the lecture and I can't + + align:start position:0% +they're later in the lecture and I can't + + + align:start position:0% +they're later in the lecture and I can't +cover them all but they're all really + + align:start position:0% +cover them all but they're all really + + + align:start position:0% +cover them all but they're all really +cool I'll mention some related systems + + align:start position:0% +cool I'll mention some related systems + + + align:start position:0% +cool I'll mention some related systems +whose designs you ought to check out if + + align:start position:0% +whose designs you ought to check out if + + + align:start position:0% +whose designs you ought to check out if +this is a topic that interests you and + + align:start position:0% +this is a topic that interests you and + + + align:start position:0% +this is a topic that interests you and +You' like to know more about it I'll + + align:start position:0% +You' like to know more about it I'll + + + align:start position:0% +You' like to know more about it I'll +talk about future work that we want to + + align:start position:0% +talk about future work that we want to + + + align:start position:0% +talk about future work that we want to +back up in tour and I hope we will have + + align:start position:0% +back up in tour and I hope we will have + + + align:start position:0% +back up in tour and I hope we will have +time to do someday and if there's time + + align:start position:0% +time to do someday and if there's time + + + align:start position:0% +time to do someday and if there's time +for questions then I'll take them and + + align:start position:0% +for questions then I'll take them and + + + align:start position:0% +for questions then I'll take them and +I've got nowhere I need to be for the + + align:start position:0% +I've got nowhere I need to be for the + + + align:start position:0% +I've got nowhere I need to be for the +next hour or so so um I and my colleague + + align:start position:0% +next hour or so so um I and my colleague + + + align:start position:0% +next hour or so so um I and my colleague +uh David over there could you wave your + + align:start position:0% +uh David over there could you wave your + + + align:start position:0% +uh David over there could you wave your +hand David we'll be hanging around + + align:start position:0% +hand David we'll be hanging around + + + align:start position:0% +hand David we'll be hanging around +somewhere and talking to anyone who + + align:start position:0% +somewhere and talking to anyone who + + + align:start position:0% +somewhere and talking to anyone who +wants to talk so right anonymity what + + align:start position:0% +wants to talk so right anonymity what + + + align:start position:0% +wants to talk so right anonymity what +what do we mean when we talk about + + align:start position:0% +what do we mean when we talk about + + + align:start position:0% +what do we mean when we talk about +anonymity there are lots of informal + + align:start position:0% +anonymity there are lots of informal + + + align:start position:0% +anonymity there are lots of informal +Notions that get used + + align:start position:0% +Notions that get used + + + align:start position:0% +Notions that get used +in um informal discussions in online and + + align:start position:0% +in um informal discussions in online and + + + align:start position:0% +in um informal discussions in online and +so on some people use anonymous to mean + + align:start position:0% +so on some people use anonymous to mean + + + align:start position:0% +so on some people use anonymous to mean +I didn't write my name on it some people + + align:start position:0% +I didn't write my name on it some people + + + align:start position:0% +I didn't write my name on it some people +use anonymous to mean well no one can + + align:start position:0% +use anonymous to mean well no one can + + + align:start position:0% +use anonymous to mean well no one can +actually prove it's me even if you + + align:start position:0% +actually prove it's me even if you + + + align:start position:0% +actually prove it's me even if you +suspect strongly what we mean is a + + align:start position:0% +suspect strongly what we mean is a + + + align:start position:0% +suspect strongly what we mean is a +number of of Notions expressed in terms + + align:start position:0% +number of of Notions expressed in terms + + + align:start position:0% +number of of Notions expressed in terms +of um of the ability of an observer or + + align:start position:0% +of um of the ability of an observer or + + + align:start position:0% +of um of the ability of an observer or +attacker on a network to link + + align:start position:0% +attacker on a network to link + + + align:start position:0% +attacker on a network to link +participants to actions these Notions + + align:start position:0% +participants to actions these Notions + + + align:start position:0% +participants to actions these Notions +come out of a uh terminology paper by + + align:start position:0% +come out of a uh terminology paper by + + + align:start position:0% +come out of a uh terminology paper by +fitman and Hanson that you can find a + + align:start position:0% +fitman and Hanson that you can find a + + + align:start position:0% +fitman and Hanson that you can find a +link to on freeh haven.nj + + align:start position:0% + + + + align:start position:0% + +is doing some activity she's + + align:start position:0% +is doing some activity she's + + + align:start position:0% +is doing some activity she's +um uh what should Ellis be doing Ellis + + align:start position:0% +um uh what should Ellis be doing Ellis + + + align:start position:0% +um uh what should Ellis be doing Ellis +is buying new + + align:start position:0% + + + + align:start position:0% + +socks and there's some attacker here + + align:start position:0% +socks and there's some attacker here + + + align:start position:0% +socks and there's some attacker here +let's call her Eve for + + align:start position:0% +let's call her Eve for + + + align:start position:0% +let's call her Eve for +now Eve can tell that Alice is doing + + align:start position:0% +now Eve can tell that Alice is doing + + + align:start position:0% +now Eve can tell that Alice is doing +something that's not what preventing + + align:start position:0% +something that's not what preventing + + + align:start position:0% +something that's not what preventing +that is not what we mean by anonymity + + align:start position:0% +that is not what we mean by anonymity + + + align:start position:0% +that is not what we mean by anonymity +that's called unobservability you can + + align:start position:0% +that's called unobservability you can + + + align:start position:0% +that's called unobservability you can +tell possibly that someone is buying + + align:start position:0% +tell possibly that someone is buying + + + align:start position:0% +tell possibly that someone is buying +socks again that's not what we mean by + + align:start position:0% +socks again that's not what we mean by + + + align:start position:0% +socks again that's not what we mean by +anonymity but what we hope is that Eve + + align:start position:0% +anonymity but what we hope is that Eve + + + align:start position:0% +anonymity but what we hope is that Eve +cannot tell that Alice in particular is + + align:start position:0% +cannot tell that Alice in particular is + + + align:start position:0% +cannot tell that Alice in particular is +buying socks and we mean that both on a + + align:start position:0% +buying socks and we mean that both on a + + + align:start position:0% +buying socks and we mean that both on a +categorical level Eve should not be able + + align:start position:0% +categorical level Eve should not be able + + + align:start position:0% +categorical level Eve should not be able +to conclude through rigorous + + align:start position:0% +to conclude through rigorous + + + align:start position:0% +to conclude through rigorous +mathematical proof this is Ellis she's + + align:start position:0% +mathematical proof this is Ellis she's + + + align:start position:0% +mathematical proof this is Ellis she's +buying socks but also Eve should not be + + align:start position:0% +buying socks but also Eve should not be + + + align:start position:0% +buying socks but also Eve should not be +able to conclude + + align:start position:0% +able to conclude + + + align:start position:0% +able to conclude +probabilistically it's Liker that Ellis + + align:start position:0% +probabilistically it's Liker that Ellis + + + align:start position:0% +probabilistically it's Liker that Ellis +is buying socks than some randomly + + align:start position:0% +is buying socks than some randomly + + + align:start position:0% +is buying socks than some randomly +selected person and also we would like + + align:start position:0% +selected person and also we would like + + + align:start position:0% +selected person and also we would like +Eve not even not to be able to include + + align:start position:0% +Eve not even not to be able to include + + + align:start position:0% +Eve not even not to be able to include +after observing many Alice activities + + align:start position:0% +after observing many Alice activities + + + align:start position:0% +after observing many Alice activities +Alice sometimes buys socks even if I + + align:start position:0% +Alice sometimes buys socks even if I + + + align:start position:0% +Alice sometimes buys socks even if I +don't know some particular activity of + + align:start position:0% +don't know some particular activity of + + + align:start position:0% +don't know some particular activity of +Alice's is a socks + + align:start position:0% + + + + align:start position:0% + +purchase there are other ideas that are + + align:start position:0% +purchase there are other ideas that are + + + align:start position:0% +purchase there are other ideas that are +related one idea is unlinkability + + align:start position:0% +related one idea is unlinkability + + + align:start position:0% +related one idea is unlinkability +unlinkability + + align:start position:0% +unlinkability + + + align:start position:0% +unlinkability +is you is there's like a long-term + + align:start position:0% +is you is there's like a long-term + + + align:start position:0% +is you is there's like a long-term +profile you of Alice so for instance + + align:start position:0% +profile you of Alice so for instance + + + align:start position:0% +profile you of Alice so for instance +Alice has been posting as um + + align:start position:0% +Alice has been posting as um + + + align:start position:0% +Alice has been posting as um +um I'm never good at picking names for + + align:start position:0% +um I'm never good at picking names for + + + align:start position:0% +um I'm never good at picking names for +my example Alice has been posting as + + align:start position:0% + + + + align:start position:0% + +Bob and writing a political blog that + + align:start position:0% +Bob and writing a political blog that + + + align:start position:0% +Bob and writing a political blog that +would disrupt her career uh that would + + align:start position:0% +would disrupt her career uh that would + + + align:start position:0% +would disrupt her career uh that would +that would offend her department head + + align:start position:0% +that would offend her department head + + + align:start position:0% +that would offend her department head +and disrupt her career as a computer + + align:start position:0% +and disrupt her career as a computer + + + align:start position:0% +and disrupt her career as a computer +security lecturer so um she's been + + align:start position:0% +security lecturer so um she's been + + + align:start position:0% +security lecturer so um she's been +writing as Bob unlinkability + + align:start position:0% +writing as Bob unlinkability + + + align:start position:0% +writing as Bob unlinkability +is the um is Eve's inability to link + + align:start position:0% +is the um is Eve's inability to link + + + align:start position:0% +is the um is Eve's inability to link +Alis to a particular profile uh final + + align:start position:0% +Alis to a particular profile uh final + + + align:start position:0% +Alis to a particular profile uh final +notion unobservability + + align:start position:0% +notion unobservability + + + align:start position:0% +notion unobservability +you some systems try to + + align:start position:0% +you some systems try to + + + align:start position:0% +you some systems try to +provide um try to make it impossible to + + align:start position:0% +provide um try to make it impossible to + + + align:start position:0% +provide um try to make it impossible to +even tell that Ellis is online that + + align:start position:0% +even tell that Ellis is online that + + + align:start position:0% +even tell that Ellis is online that +Ellis is connecting to anybody at all + + align:start position:0% +Ellis is connecting to anybody at all + + + align:start position:0% +Ellis is connecting to anybody at all +the that Alis is doing any activity + + align:start position:0% +the that Alis is doing any activity + + + align:start position:0% +the that Alis is doing any activity +these + + align:start position:0% +these + + + align:start position:0% +these +are rather hard to build I'll talk a + + align:start position:0% +are rather hard to build I'll talk a + + + align:start position:0% +are rather hard to build I'll talk a +little bit more about to what extent + + align:start position:0% +little bit more about to what extent + + + align:start position:0% +little bit more about to what extent +they are useful later uh something that + + align:start position:0% +they are useful later uh something that + + + align:start position:0% +they are useful later uh something that +is useful in that area is you might want + + align:start position:0% +is useful in that area is you might want + + + align:start position:0% +is useful in that area is you might want +to conceal that Alice is using an + + align:start position:0% +to conceal that Alice is using an + + + align:start position:0% +to conceal that Alice is using an +anonymity system but not that she is on + + align:start position:0% +anonymity system but not that she is on + + + align:start position:0% +anonymity system but not that she is on +the internet that's more achievable than + + align:start position:0% +the internet that's more achievable than + + + align:start position:0% +the internet that's more achievable than +concealing the fact that Alice is on the + + align:start position:0% +concealing the fact that Alice is on the + + + align:start position:0% +concealing the fact that Alice is on the +internet + + align:start position:0% +internet + + + align:start position:0% +internet +entirely so why did I start working on + + align:start position:0% +entirely so why did I start working on + + + align:start position:0% +entirely so why did I start working on +this in the first place well partially + + align:start position:0% +this in the first place well partially + + + align:start position:0% +this in the first place well partially +because of the engineers's itch it's a + + align:start position:0% +because of the engineers's itch it's a + + + align:start position:0% +because of the engineers's itch it's a +cool problem it's an interesting problem + + align:start position:0% +cool problem it's an interesting problem + + + align:start position:0% +cool problem it's an interesting problem +nobody else was actually working on it + + align:start position:0% +nobody else was actually working on it + + + align:start position:0% +nobody else was actually working on it +and my friend Roger got a contract to uh + + align:start position:0% +and my friend Roger got a contract to uh + + + align:start position:0% +and my friend Roger got a contract to uh +finish up a stalled research project + + align:start position:0% +finish up a stalled research project + + + align:start position:0% +finish up a stalled research project +before the grant expired and he did it + + align:start position:0% +before the grant expired and he did it + + + align:start position:0% +before the grant expired and he did it +well enough that I said hey I'll join up + + align:start position:0% +well enough that I said hey I'll join up + + + align:start position:0% +well enough that I said hey I'll join up +and you've got some more funding + + align:start position:0% +and you've got some more funding + + + align:start position:0% +and you've got some more funding +foration sure I'll I'll join in after a + + align:start position:0% +foration sure I'll I'll join in after a + + + align:start position:0% +foration sure I'll I'll join in after a +while we formed a nonprofit and G + + align:start position:0% +while we formed a nonprofit and G + + + align:start position:0% +while we formed a nonprofit and G +released everything as open source so + + align:start position:0% +released everything as open source so + + + align:start position:0% +released everything as open source so +that's part of it but for deeper + + align:start position:0% +that's part of it but for deeper + + + align:start position:0% +that's part of it but for deeper +motivations I think Humanity's got a lot + + align:start position:0% +motivations I think Humanity's got a lot + + + align:start position:0% +motivations I think Humanity's got a lot +of problems that can only be solved + + align:start position:0% +of problems that can only be solved + + + align:start position:0% +of problems that can only be solved +through better and more dedicated + + align:start position:0% +through better and more dedicated + + + align:start position:0% +through better and more dedicated +communication Freer expression and more + + align:start position:0% +communication Freer expression and more + + + align:start position:0% +communication Freer expression and more +free of thought and I don't know how to + + align:start position:0% +free of thought and I don't know how to + + + align:start position:0% +free of thought and I don't know how to +solve these + + align:start position:0% +solve these + + + align:start position:0% +solve these +problems all I think I can do is try to + + align:start position:0% +problems all I think I can do is try to + + + align:start position:0% +problems all I think I can do is try to +make sure that what I see as + + align:start position:0% +make sure that what I see as + + + align:start position:0% +make sure that what I see as +inhibiting discussion thought speech + + align:start position:0% +inhibiting discussion thought speech + + + align:start position:0% +inhibiting discussion thought speech +becomes harder to do so that's more or + + align:start position:0% +becomes harder to do so that's more or + + + align:start position:0% +becomes harder to do so that's more or +less where I'm at y uh so I know there + + align:start position:0% +less where I'm at y uh so I know there + + + align:start position:0% +less where I'm at y uh so I know there +are many good reasons to use T please + + align:start position:0% +are many good reasons to use T please + + + align:start position:0% +are many good reasons to use T please +don't see this as criticism I'm just + + align:start position:0% +don't see this as criticism I'm just + + + align:start position:0% +don't see this as criticism I'm just +curious uh what is your opinion as far + + align:start position:0% +curious uh what is your opinion as far + + + align:start position:0% +curious uh what is your opinion as far +as um you know criminal activity what is + + align:start position:0% +as um you know criminal activity what is + + + align:start position:0% +as um you know criminal activity what is +my opinion on criminal activity some + + align:start position:0% +my opinion on criminal activity some + + + align:start position:0% +my opinion on criminal activity some +laws are good some laws are bad my + + align:start position:0% +laws are good some laws are bad my + + + align:start position:0% +laws are good some laws are bad my +lawyers would tell me never to advise + + align:start position:0% +lawyers would tell me never to advise + + + align:start position:0% +lawyers would tell me never to advise +anyone to break the law um I feel my + + align:start position:0% +anyone to break the law um I feel my + + + align:start position:0% +anyone to break the law um I feel my +goal was not to enable criminal activity + + align:start position:0% +goal was not to enable criminal activity + + + align:start position:0% +goal was not to enable criminal activity +against most of the laws I agree with in + + align:start position:0% +against most of the laws I agree with in + + + align:start position:0% +against most of the laws I agree with in +places where criticizing the government + + align:start position:0% +places where criticizing the government + + + align:start position:0% +places where criticizing the government +is illegal then I'm in favor of criminal + + align:start position:0% +is illegal then I'm in favor of criminal + + + align:start position:0% +is illegal then I'm in favor of criminal +activity of that kind I so in that case + + align:start position:0% +activity of that kind I so in that case + + + align:start position:0% +activity of that kind I so in that case +I suppose I was supporting that kind of + + align:start position:0% +I suppose I was supporting that kind of + + + align:start position:0% +I suppose I was supporting that kind of +criminal + + align:start position:0% +criminal + + + align:start position:0% +criminal +activity my stance on whether it's a + + align:start position:0% +activity my stance on whether it's a + + + align:start position:0% +activity my stance on whether it's a +problem that an anonymity Network gets + + align:start position:0% +problem that an anonymity Network gets + + + align:start position:0% +problem that an anonymity Network gets +used for criminal activity in general to + + align:start position:0% +used for criminal activity in general to + + + align:start position:0% +used for criminal activity in general to +the extent that there are good laws I + + align:start position:0% +the extent that there are good laws I + + + align:start position:0% +the extent that there are good laws I +would prefer that people not break them + + align:start position:0% +would prefer that people not break them + + + align:start position:0% +would prefer that people not break them +I would however think that any computer + + align:start position:0% +I would however think that any computer + + + align:start position:0% +I would however think that any computer +security system that does not get used + + align:start position:0% +security system that does not get used + + + align:start position:0% +security system that does not get used +by criminals is probably a very bad + + align:start position:0% +by criminals is probably a very bad + + + align:start position:0% +by criminals is probably a very bad +computer security system if the + + align:start position:0% +computer security system if the + + + align:start position:0% +computer security system if the +computers if the criminals are making + + align:start position:0% +computers if the criminals are making + + + align:start position:0% +computers if the criminals are making +any kind of good decision making policy + + align:start position:0% +any kind of good decision making policy + + + align:start position:0% +any kind of good decision making policy +I think that if we go around Banning + + align:start position:0% +I think that if we go around Banning + + + align:start position:0% +I think that if we go around Banning +security that works for criminals we + + align:start position:0% +security that works for criminals we + + + align:start position:0% +security that works for criminals we +wind up with insecure + + align:start position:0% +wind up with insecure + + + align:start position:0% +wind up with insecure +systems um so that's more or less where + + align:start position:0% +systems um so that's more or less where + + + align:start position:0% +systems um so that's more or less where +I stand on it I'm not really the + + align:start position:0% +I stand on it I'm not really the + + + align:start position:0% +I stand on it I'm not really the +philosopher of it this though I'm more + + align:start position:0% +philosopher of it this though I'm more + + + align:start position:0% +philosopher of it this though I'm more +of the programmer + + align:start position:0% +of the programmer + + + align:start position:0% +of the programmer +so I'm going to be giving really trit + + align:start position:0% +so I'm going to be giving really trit + + + align:start position:0% +so I'm going to be giving really trit +answers to philosophical and legal + + align:start position:0% +answers to philosophical and legal + + + align:start position:0% +answers to philosophical and legal +questions also I am not a lawyer and + + align:start position:0% +questions also I am not a lawyer and + + + align:start position:0% +questions also I am not a lawyer and +cannot offer legal advice do not take + + align:start position:0% +cannot offer legal advice do not take + + + align:start position:0% +cannot offer legal advice do not take +anything I say as legal + + align:start position:0% +anything I say as legal + + + align:start position:0% +anything I say as legal +advice that said um also so at the time + + align:start position:0% +advice that said um also so at the time + + + align:start position:0% +advice that said um also so at the time +we started also a lot of these research + + align:start position:0% +we started also a lot of these research + + + align:start position:0% +we started also a lot of these research +problems I'm going to be talking about + + align:start position:0% +problems I'm going to be talking about + + + align:start position:0% +problems I'm going to be talking about +weren't even close to being solved so + + align:start position:0% +weren't even close to being solved so + + + align:start position:0% +weren't even close to being solved so +why did we start anyway instead of going + + align:start position:0% +why did we start anyway instead of going + + + align:start position:0% +why did we start anyway instead of going +straight into research one of them was + + align:start position:0% +straight into research one of them was + + + align:start position:0% +straight into research one of them was +we thought that a lot of them wouldn't + + align:start position:0% +we thought that a lot of them wouldn't + + + align:start position:0% +we thought that a lot of them wouldn't +get solved unless there was a test bed + + align:start position:0% +get solved unless there was a test bed + + + align:start position:0% +get solved unless there was a test bed +to work on and that's kind of gotten + + align:start position:0% +to work on and that's kind of gotten + + + align:start position:0% +to work on and that's kind of gotten +born out + + align:start position:0% +born out + + + align:start position:0% +born out +because tour has kind of become the + + align:start position:0% +because tour has kind of become the + + + align:start position:0% +because tour has kind of become the +research platform of choice for lots of + + align:start position:0% +research platform of choice for lots of + + + align:start position:0% +research platform of choice for lots of +work on low latency anonymity systems + + align:start position:0% +work on low latency anonymity systems + + + align:start position:0% +work on low latency anonymity systems +and has helped the fied a lot in that + + align:start position:0% +and has helped the fied a lot in that + + + align:start position:0% +and has helped the fied a lot in that +way but also you know 10 years on and a + + align:start position:0% +way but also you know 10 years on and a + + + align:start position:0% +way but also you know 10 years on and a +lot of the big problems still aren't + + align:start position:0% +lot of the big problems still aren't + + + align:start position:0% +lot of the big problems still aren't +solved so if we had waited 10 years for + + align:start position:0% +solved so if we had waited 10 years for + + + align:start position:0% +solved so if we had waited 10 years for +everything to get fixed that we would + + align:start position:0% +everything to get fixed that we would + + + align:start position:0% +everything to get fixed that we would +have been Waiting in + + align:start position:0% +have been Waiting in + + + align:start position:0% +have been Waiting in +Vain + + align:start position:0% +Vain + + + align:start position:0% +Vain +so why do it then partially because we + + align:start position:0% +so why do it then partially because we + + + align:start position:0% +so why do it then partially because we +thought + + align:start position:0% +thought + + + align:start position:0% +thought +that having + + align:start position:0% +that having + + + align:start position:0% +that having +a having a system out there would + + align:start position:0% +a having a system out there would + + + align:start position:0% +a having a system out there would +improve long-term outcomes for the world + + align:start position:0% +improve long-term outcomes for the world + + + align:start position:0% +improve long-term outcomes for the world +that is it's really easy to argue that + + align:start position:0% +that is it's really easy to argue that + + + align:start position:0% +that is it's really easy to argue that +something that doesn't exist should be + + align:start position:0% +something that doesn't exist should be + + + align:start position:0% +something that doesn't exist should be +banned arguments against civilian use of + + align:start position:0% +banned arguments against civilian use of + + + align:start position:0% +banned arguments against civilian use of +cryptography were much easier to make in + + align:start position:0% +cryptography were much easier to make in + + + align:start position:0% +cryptography were much easier to make in +public in 1990 than they are today + + align:start position:0% +public in 1990 than they are today + + + align:start position:0% +public in 1990 than they are today +because there was almost no civilian use + + align:start position:0% +because there was almost no civilian use + + + align:start position:0% +because there was almost no civilian use +of strong cryptography then and you + + align:start position:0% +of strong cryptography then and you + + + align:start position:0% +of strong cryptography then and you +could argue that if that you know if + + align:start position:0% +could argue that if that you know if + + + align:start position:0% +could argue that if that you know if +anything's stronger than Dees is legal + + align:start position:0% +anything's stronger than Dees is legal + + + align:start position:0% +anything's stronger than Dees is legal +then civilization will + + align:start position:0% +then civilization will + + + align:start position:0% +then civilization will +collapse um criminals will never be + + align:start position:0% +collapse um criminals will never be + + + align:start position:0% +collapse um criminals will never be +caught + + align:start position:0% +caught + + + align:start position:0% +caught +and um and organized crime will take + + align:start position:0% +and um and organized crime will take + + + align:start position:0% +and um and organized crime will take +over everything but you couldn't really + + align:start position:0% +over everything but you couldn't really + + + align:start position:0% +over everything but you couldn't really +argue that that was the inevitable + + align:start position:0% +argue that that was the inevitable + + + align:start position:0% +argue that that was the inevitable +consequence of cryptography in 2000 + + align:start position:0% +consequence of cryptography in 2000 + + + align:start position:0% +consequence of cryptography in 2000 +because cryptography had already been + + align:start position:0% +because cryptography had already been + + + align:start position:0% +because cryptography had already been +out there and it turned out not to end + + align:start position:0% +out there and it turned out not to end + + + align:start position:0% +out there and it turned out not to end +the world further it was harder to argue + + align:start position:0% +the world further it was harder to argue + + + align:start position:0% +the world further it was harder to argue +for a cryptography ban in 2000 + + align:start position:0% +for a cryptography ban in 2000 + + + align:start position:0% +for a cryptography ban in 2000 +because there was a large constituency + + align:start position:0% +because there was a large constituency + + + align:start position:0% +because there was a large constituency +in favor of the use of cryptography that + + align:start position:0% +in favor of the use of cryptography that + + + align:start position:0% +in favor of the use of cryptography that +is if someone says if someone in 1985 + + align:start position:0% +is if someone says if someone in 1985 + + + align:start position:0% +is if someone says if someone in 1985 +says let's ban strong cryptography well + + align:start position:0% +says let's ban strong cryptography well + + + align:start position:0% +says let's ban strong cryptography well +banks are using strong cryptography so + + align:start position:0% +banks are using strong cryptography so + + + align:start position:0% +banks are using strong cryptography so +they'll ask for an exemption but other + + align:start position:0% +they'll ask for an exemption but other + + + align:start position:0% +they'll ask for an exemption but other +than that there weren't a lot of users + + align:start position:0% +than that there weren't a lot of users + + + align:start position:0% +than that there weren't a lot of users +of strong cryptography in the civilian + + align:start position:0% +of strong cryptography in the civilian + + + align:start position:0% +of strong cryptography in the civilian +space but if someone in 2000 said let's + + align:start position:0% +space but if someone in 2000 said let's + + + align:start position:0% +space but if someone in 2000 said let's +ban strong cryptography that would be + + align:start position:0% +ban strong cryptography that would be + + + align:start position:0% +ban strong cryptography that would be +every internet + + align:start position:0% +every internet + + + align:start position:0% +every internet +company everyone running an https page + + align:start position:0% +company everyone running an https page + + + align:start position:0% +company everyone running an https page +would start waving their hands and + + align:start position:0% +would start waving their hands and + + + align:start position:0% +would start waving their hands and +shouting about it and and nowadays + + align:start position:0% +shouting about it and and nowadays + + + align:start position:0% +shouting about it and and nowadays +strong cryptography bands are probably + + align:start position:0% +strong cryptography bands are probably + + + align:start position:0% +strong cryptography bands are probably +unfeasible although people keep bringing + + align:start position:0% +unfeasible although people keep bringing + + + align:start position:0% +unfeasible although people keep bringing +back the idea and again I'm not the + + align:start position:0% +back the idea and again I'm not the + + + align:start position:0% +back the idea and again I'm not the +philosopher or political scientist of + + align:start position:0% +philosopher or political scientist of + + + align:start position:0% +philosopher or political scientist of +the movement + + align:start position:0% +the movement + + + align:start position:0% +the movement +so some folks asked me what's your + + align:start position:0% +so some folks asked me what's your + + + align:start position:0% +so some folks asked me what's your +threat model it's good to be thinking in + + align:start position:0% +threat model it's good to be thinking in + + + align:start position:0% +threat model it's good to be thinking in +terms of threat models unfortunately our + + align:start position:0% +terms of threat models unfortunately our + + + align:start position:0% +terms of threat models unfortunately our +threat model is kind of weird we started + + align:start position:0% +threat model is kind of weird we started + + + align:start position:0% +threat model is kind of weird we started +not with a adversary requirement but we + + align:start position:0% +not with a adversary requirement but we + + + align:start position:0% +not with a adversary requirement but we +started with a usability + + align:start position:0% +started with a usability + + + align:start position:0% +started with a usability +requirement the usability requirement we + + align:start position:0% +requirement the usability requirement we + + + align:start position:0% +requirement the usability requirement we +gave ourselves to begin is this has to + + align:start position:0% +gave ourselves to begin is this has to + + + align:start position:0% +gave ourselves to begin is this has to +be useful for web browsing this has to + + align:start position:0% +be useful for web browsing this has to + + + align:start position:0% +be useful for web browsing this has to +be useful for interactive protocols + + align:start position:0% + + + + align:start position:0% + +and it actually needs to see use subject + + align:start position:0% +and it actually needs to see use subject + + + align:start position:0% +and it actually needs to see use subject +to that we want to maximize security so + + align:start position:0% +to that we want to maximize security so + + + align:start position:0% +to that we want to maximize security so +our thread model has lots of weird + + align:start position:0% +our thread model has lots of weird + + + align:start position:0% +our thread model has lots of weird +Corners in it if you actually write it + + align:start position:0% +Corners in it if you actually write it + + + align:start position:0% +Corners in it if you actually write it +out as what can an attacker do what can + + align:start position:0% +out as what can an attacker do what can + + + align:start position:0% +out as what can an attacker do what can +under what circumstances and how and + + align:start position:0% +under what circumstances and how and + + + align:start position:0% +under what circumstances and how and +that's because we've set ourselves the + + align:start position:0% +that's because we've set ourselves the + + + align:start position:0% +that's because we've set ourselves the +goal of it has to work for the + + align:start position:0% +goal of it has to work for the + + + align:start position:0% +goal of it has to work for the +web um and I'll return to that in a + + align:start position:0% +web um and I'll return to that in a + + + align:start position:0% +web um and I'll return to that in a +minute or two but let's sort of talk + + align:start position:0% +minute or two but let's sort of talk + + + align:start position:0% +minute or two but let's sort of talk +about now how we can use + + align:start position:0% +about now how we can use + + + align:start position:0% +about now how we can use +um how we can use forward anony how we + + align:start position:0% +um how we can use forward anony how we + + + align:start position:0% +um how we can use forward anony how we +build forward anonymity + + align:start position:0% +build forward anonymity + + + align:start position:0% +build forward anonymity +so here's Ellis she wants to buy + + align:start position:0% +so here's Ellis she wants to buy + + + align:start position:0% +so here's Ellis she wants to buy +socks so okay let's say that + + align:start position:0% +socks so okay let's say that + + + align:start position:0% +socks so okay let's say that +Alice runs a computer let's call it R + + align:start position:0% +Alice runs a computer let's call it R + + + align:start position:0% +Alice runs a computer let's call it R +for relay and this computer relays her + + align:start position:0% +for relay and this computer relays her + + + align:start position:0% +for relay and this computer relays her +traffic to um I want to say socks.com + + align:start position:0% +traffic to um I want to say socks.com + + + align:start position:0% +traffic to um I want to say socks.com +but I'm afraid that will turn out to be + + align:start position:0% +but I'm afraid that will turn out to be + + + align:start position:0% +but I'm afraid that will turn out to be +something horrible so um.com yeah they + + align:start position:0% +something horrible so um.com yeah they + + + align:start position:0% +something horrible so um.com yeah they +sell socks too all right so Ellis wants + + align:start position:0% +sell socks too all right so Ellis wants + + + align:start position:0% +sell socks too all right so Ellis wants +to buy some socks from z.com and she's + + align:start position:0% +to buy some socks from z.com and she's + + + align:start position:0% +to buy some socks from z.com and she's +going going through a relay um + + align:start position:0% +going going through a relay um + + + align:start position:0% +going going through a relay um +well I said Alice runs a re relay anyone + + align:start position:0% +well I said Alice runs a re relay anyone + + + align:start position:0% +well I said Alice runs a re relay anyone +any EES dropper who's looking at this + + align:start position:0% +any EES dropper who's looking at this + + + align:start position:0% +any EES dropper who's looking at this +will say uh that's Alice's computer it's + + align:start position:0% +will say uh that's Alice's computer it's + + + align:start position:0% +will say uh that's Alice's computer it's +probably Alice all right so let's have + + align:start position:0% +probably Alice all right so let's have + + + align:start position:0% +probably Alice all right so let's have +somebody else run a relay and have lots + + align:start position:0% +somebody else run a relay and have lots + + + align:start position:0% +somebody else run a relay and have lots +of other users all visit it I'll call + + align:start position:0% +of other users all visit it I'll call + + + align:start position:0% +of other users all visit it I'll call +them A2 and A3 because there aren't + + align:start position:0% +them A2 and A3 because there aren't + + + align:start position:0% +them A2 and A3 because there aren't +enough standard cryptography person + + align:start position:0% +enough standard cryptography person + + + align:start position:0% +enough standard cryptography person +names um by books + + align:start position:0% + + + + align:start position:0% + +tweet cat + + align:start position:0% + + + + align:start position:0% + +pictures this is like 80% of what people + + align:start position:0% +pictures this is like 80% of what people + + + align:start position:0% +pictures this is like 80% of what people +do on the internet right um so now we + + align:start position:0% +do on the internet right um so now we + + + align:start position:0% +do on the internet right um so now we +have three people all going into this + + align:start position:0% +have three people all going into this + + + align:start position:0% +have three people all going into this +relay three streams exiting someone + + align:start position:0% +relay three streams exiting someone + + + align:start position:0% +relay three streams exiting someone +who's watching the relay can't easily + + align:start position:0% +who's watching the relay can't easily + + + align:start position:0% +who's watching the relay can't easily +correlate should not be we hope we we'll + + align:start position:0% +correlate should not be we hope we we'll + + + align:start position:0% +correlate should not be we hope we we'll +return return to that too that this + + align:start position:0% +return return to that too that this + + + align:start position:0% +return return to that too that this +Alice is buying socks this Alice buying + + align:start position:0% +Alice is buying socks this Alice buying + + + align:start position:0% +Alice is buying socks this Alice buying +books this Alice his tweeting + + align:start position:0% +books this Alice his tweeting + + + align:start position:0% +books this Alice his tweeting +CeX well except if they're watching this + + align:start position:0% +CeX well except if they're watching this + + + align:start position:0% +CeX well except if they're watching this +side of the connections they can see + + align:start position:0% +side of the connections they can see + + + align:start position:0% +side of the connections they can see +Alice telling the Relay please connect + + align:start position:0% +Alice telling the Relay please connect + + + align:start position:0% +Alice telling the Relay please connect +me to zap.com all right so we'll add + + align:start position:0% +me to zap.com all right so we'll add + + + align:start position:0% +me to zap.com all right so we'll add +some encryption we'll maybe do TLS on + + align:start position:0% +some encryption we'll maybe do TLS on + + + align:start position:0% +some encryption we'll maybe do TLS on +all of these links so to the extent that + + align:start position:0% +all of these links so to the extent that + + + align:start position:0% +all of these links so to the extent that +you can't break TLS to the extent you + + align:start position:0% +you can't break TLS to the extent you + + + align:start position:0% +you can't break TLS to the extent you +can't correlate this to this then they + + align:start position:0% +can't correlate this to this then they + + + align:start position:0% +can't correlate this to this then they +get some privacy well that's still not + + align:start position:0% +get some privacy well that's still not + + + align:start position:0% +get some privacy well that's still not +good enough though because um first off + + align:start position:0% +good enough though because um first off + + + align:start position:0% +good enough though because um first off +we're assuming that um this relay is + + align:start position:0% +we're assuming that um this relay is + + + align:start position:0% +we're assuming that um this relay is +fully trusted I assume you've done the + + align:start position:0% +fully trusted I assume you've done the + + + align:start position:0% +fully trusted I assume you've done the +definition of of trusted and why it + + align:start position:0% +definition of of trusted and why it + + + align:start position:0% +definition of of trusted and why it +doesn't actually mean trusted okay good + + align:start position:0% +doesn't actually mean trusted okay good + + + align:start position:0% +doesn't actually mean trusted okay good +um this is trusted in the sense that it + + align:start position:0% +um this is trusted in the sense that it + + + align:start position:0% +um this is trusted in the sense that it +can break the whole system trusted in + + align:start position:0% +can break the whole system trusted in + + + align:start position:0% +can break the whole system trusted in +the sense that you can't help but trust + + align:start position:0% +the sense that you can't help but trust + + + align:start position:0% +the sense that you can't help but trust +it not trusted in the sense that is + + align:start position:0% +it not trusted in the sense that is + + + align:start position:0% +it not trusted in the sense that is +actually trustworthy so all right we can + + align:start position:0% +actually trustworthy so all right we can + + + align:start position:0% +actually trustworthy so all right we can +introduce multiple relays we can have + + align:start position:0% +introduce multiple relays we can have + + + align:start position:0% +introduce multiple relays we can have +different relays run by different + + align:start position:0% +different relays run by different + + + align:start position:0% +different relays run by different +people we can have + + align:start position:0% +people we can have + + + align:start position:0% +people we can have +um this is not actually the topology we + + align:start position:0% +um this is not actually the topology we + + + align:start position:0% +um this is not actually the topology we +use but my Blackboard technique is + + align:start position:0% +use but my Blackboard technique is + + + align:start position:0% +use but my Blackboard technique is +terrible and I don't want to read I + + align:start position:0% +terrible and I don't want to read I + + + align:start position:0% +terrible and I don't want to read I +don't want to redraw + + align:start position:0% + + + + align:start position:0% + +anything we can imagine tunneling these + + align:start position:0% +anything we can imagine tunneling these + + + align:start position:0% +anything we can imagine tunneling these +connections through multiple relays Each + + align:start position:0% +connections through multiple relays Each + + + align:start position:0% +connections through multiple relays Each +of which removes a single layer of + + align:start position:0% +of which removes a single layer of + + + align:start position:0% +of which removes a single layer of +encryption so this all this relay sees + + align:start position:0% +encryption so this all this relay sees + + + align:start position:0% +encryption so this all this relay sees +is Alice is doing something all this + + align:start position:0% +is Alice is doing something all this + + + align:start position:0% +is Alice is doing something all this +relay sees is someone is buying socks + + align:start position:0% +relay sees is someone is buying socks + + + align:start position:0% +relay sees is someone is buying socks +but this one just sees someone's buying + + align:start position:0% +but this one just sees someone's buying + + + align:start position:0% +but this one just sees someone's buying +socks the connection came from this + + align:start position:0% +socks the connection came from this + + + align:start position:0% +socks the connection came from this +relay this just sees else is doing + + align:start position:0% +relay this just sees else is doing + + + align:start position:0% +relay this just sees else is doing +something and it forwards onto this + + align:start position:0% +something and it forwards onto this + + + align:start position:0% +something and it forwards onto this +relay and no single party ought to be + + align:start position:0% +relay and no single party ought to be + + + align:start position:0% +relay and no single party ought to be +able to correlate the whole + + align:start position:0% +able to correlate the whole + + + align:start position:0% +able to correlate the whole +thing now we come to a major design + + align:start position:0% +thing now we come to a major design + + + align:start position:0% +thing now we come to a major design +Point Let's suppose that that Eve is + + align:start position:0% +Point Let's suppose that that Eve is + + + align:start position:0% +Point Let's suppose that that Eve is +watching here and + + align:start position:0% +watching here and + + + align:start position:0% +watching here and +here nothing I've said so far does + + align:start position:0% +here nothing I've said so far does + + + align:start position:0% +here nothing I've said so far does +anything to obscure the the timing and + + align:start position:0% +anything to obscure the the timing and + + + align:start position:0% +anything to obscure the the timing and +volume of Alice's P packets oh sure + + align:start position:0% +volume of Alice's P packets oh sure + + + align:start position:0% +volume of Alice's P packets oh sure +there will be some some some trivial + + align:start position:0% +there will be some some some trivial + + + align:start position:0% +there will be some some some trivial +noise added from all the computation and + + align:start position:0% +noise added from all the computation and + + + align:start position:0% +noise added from all the computation and +decryption these things do from Network + + align:start position:0% +decryption these things do from Network + + + align:start position:0% +decryption these things do from Network +latency and so on but ultimately if + + align:start position:0% +latency and so on but ultimately if + + + align:start position:0% +latency and so on but ultimately if +Alice is sending a kilobyte in then in + + align:start position:0% +Alice is sending a kilobyte in then in + + + align:start position:0% +Alice is sending a kilobyte in then in +the design I catched out so far a + + align:start position:0% +the design I catched out so far a + + + align:start position:0% +the design I catched out so far a +kilobyte is coming out if Alis is and if + + align:start position:0% +kilobyte is coming out if Alis is and if + + + align:start position:0% +kilobyte is coming out if Alis is and if +the socks web page is 64k long and is + + align:start position:0% +the socks web page is 64k long and is + + + align:start position:0% +the socks web page is 64k long and is +served by this web server at + + align:start position:0% +served by this web server at + + + align:start position:0% +served by this web server at +11:26 then Alice is going to get + + align:start position:0% +11:26 then Alice is going to get + + + align:start position:0% +11:26 then Alice is going to get +something about 64k along at 1126 or + + align:start position:0% +something about 64k along at 1126 or + + + align:start position:0% +something about 64k along at 1126 or +1127 or + + align:start position:0% +1127 or + + + align:start position:0% +1127 or +so now with some statistics Eve can + + align:start position:0% +so now with some statistics Eve can + + + align:start position:0% +so now with some statistics Eve can +correlate some of these streams if we + + align:start position:0% +correlate some of these streams if we + + + align:start position:0% +correlate some of these streams if we +don't obscure volume and timing + + align:start position:0% +don't obscure volume and timing + + + align:start position:0% +don't obscure volume and timing +information there are designs that do + + align:start position:0% +information there are designs that do + + + align:start position:0% +information there are designs that do +obscure volume and timey information the + + align:start position:0% +obscure volume and timey information the + + + align:start position:0% +obscure volume and timey information the +good ones + + align:start position:0% +good ones + + + align:start position:0% +good ones +are usually come out of chow and mix + + align:start position:0% +are usually come out of chow and mix + + + align:start position:0% +are usually come out of chow and mix +Nets although there's some work on DC + + align:start position:0% +Nets although there's some work on DC + + + align:start position:0% +Nets although there's some work on DC +Nets you could have something where each + + align:start position:0% +Nets you could have something where each + + + align:start position:0% +Nets you could have something where each +of these nodes received large number of + + align:start position:0% +of these nodes received large number of + + + align:start position:0% +of these nodes received large number of +requests just bashed up all the requests + + align:start position:0% +requests just bashed up all the requests + + + align:start position:0% +requests just bashed up all the requests +it got for an hour reordered them and + + align:start position:0% +it got for an hour reordered them and + + + align:start position:0% +it got for an hour reordered them and +transmitted them all at once and you + + align:start position:0% +transmitted them all at once and you + + + align:start position:0% +transmitted them all at once and you +could also say all requests must be the + + align:start position:0% +could also say all requests must be the + + + align:start position:0% +could also say all requests must be the +same size requests are 1K responses are + + align:start position:0% +same size requests are 1K responses are + + + align:start position:0% +same size requests are 1K responses are + + align:start position:0% + + + align:start position:0% +Megabyte and with with some more work + + align:start position:0% +Megabyte and with with some more work + + + align:start position:0% +Megabyte and with with some more work +like that you would get something that + + align:start position:0% +like that you would get something that + + + align:start position:0% +like that you would get something that +would let you send an email on the order + + align:start position:0% +would let you send an email on the order + + + align:start position:0% +would let you send an email on the order +of our that would arrive in order of + + align:start position:0% +of our that would arrive in order of + + + align:start position:0% +of our that would arrive in order of +hours or get a web page in order of 2 N + + align:start position:0% +hours or get a web page in order of 2 N + + + align:start position:0% +hours or get a web page in order of 2 N +time assuming that you optimize it to a + + align:start position:0% +time assuming that you optimize it to a + + + align:start position:0% +time assuming that you optimize it to a +single round + + align:start position:0% +single round + + + align:start position:0% +single round +trip these systems exist but and existed + + align:start position:0% +trip these systems exist but and existed + + + align:start position:0% +trip these systems exist but and existed +when we started doing tour they don't + + align:start position:0% +when we started doing tour they don't + + + align:start position:0% +when we started doing tour they don't +get a lot of use though um I actually + + align:start position:0% +get a lot of use though um I actually + + + align:start position:0% +get a lot of use though um I actually +wrote one called mix minion that was a + + align:start position:0% +wrote one called mix minion that was a + + + align:start position:0% +wrote one called mix minion that was a +successor to the Mixmaster + + align:start position:0% +successor to the Mixmaster + + + align:start position:0% +successor to the Mixmaster +remailer I have not gotten a remailer + + align:start position:0% +remailer I have not gotten a remailer + + + align:start position:0% +remailer I have not gotten a remailer +message in the last three + + align:start position:0% +message in the last three + + + align:start position:0% +message in the last three +years uh Tor has millions of users + + align:start position:0% +years uh Tor has millions of users + + + align:start position:0% +years uh Tor has millions of users +remailers it's unclear whether they've + + align:start position:0% +remailers it's unclear whether they've + + + align:start position:0% +remailers it's unclear whether they've +got on the more than on the order of + + align:start position:0% +got on the more than on the order of + + + align:start position:0% +got on the more than on the order of +hundreds so you might think well still + + align:start position:0% +hundreds so you might think well still + + + align:start position:0% +hundreds so you might think well still +though it's better anonymity for the + + align:start position:0% +though it's better anonymity for the + + + align:start position:0% +though it's better anonymity for the +people really need it except if you've + + align:start position:0% +people really need it except if you've + + + align:start position:0% +people really need it except if you've +only got on the order of hundreds of + + align:start position:0% +only got on the order of hundreds of + + + align:start position:0% +only got on the order of hundreds of +users then you're not really providing + + align:start position:0% +users then you're not really providing + + + align:start position:0% +users then you're not really providing +them all that much anonymity against + + align:start position:0% +them all that much anonymity against + + + align:start position:0% +them all that much anonymity against +this kind of adversary anyway because + + align:start position:0% +this kind of adversary anyway because + + + align:start position:0% +this kind of adversary anyway because +this such an adversary can simply go + + align:start position:0% +this such an adversary can simply go + + + align:start position:0% +this such an adversary can simply go +okay there's 100 people well the message + + align:start position:0% +okay there's 100 people well the message + + + align:start position:0% +okay there's 100 people well the message +I want to investigate was looking at a + + align:start position:0% +I want to investigate was looking at a + + + align:start position:0% +I want to investigate was looking at a +Bulgarian website how many of them speak + + align:start position:0% +Bulgarian website how many of them speak + + + align:start position:0% +Bulgarian website how many of them speak +Bulgarian okay that's + + align:start position:0% +Bulgarian okay that's + + + align:start position:0% +Bulgarian okay that's +five uh um the saying is anonymity loves + + align:start position:0% +five uh um the saying is anonymity loves + + + align:start position:0% +five uh um the saying is anonymity loves +company unless you have a large user + + align:start position:0% +company unless you have a large user + + + align:start position:0% +company unless you have a large user +base no system can actually provide + + align:start position:0% +base no system can actually provide + + + align:start position:0% +base no system can actually provide +anonymity and that's why also in this + + align:start position:0% +anonymity and that's why also in this + + + align:start position:0% +anonymity and that's why also in this +design if if these alyses all belong to + + align:start position:0% +design if if these alyses all belong to + + + align:start position:0% +design if if these alyses all belong to +an organization they ought to have a + + align:start position:0% +an organization they ought to have a + + + align:start position:0% +an organization they ought to have a +shared public system rather than a + + align:start position:0% +shared public system rather than a + + + align:start position:0% +shared public system rather than a +private one like if you are if if they + + align:start position:0% +private one like if you are if if they + + + align:start position:0% +private one like if you are if if they +all work + + align:start position:0% +all work + + + align:start position:0% +all work +for MIT legal and they're investigating + + align:start position:0% +for MIT legal and they're investigating + + + align:start position:0% +for MIT legal and they're investigating +some fake MIT website that's um offering + + align:start position:0% +some fake MIT website that's um offering + + + align:start position:0% +some fake MIT website that's um offering +fake + + align:start position:0% +fake + + + align:start position:0% +fake +diplomas then if if they're just using + + align:start position:0% +diplomas then if if they're just using + + + align:start position:0% +diplomas then if if they're just using +the MIT legal anonymizer then it's not + + align:start position:0% +the MIT legal anonymizer then it's not + + + align:start position:0% +the MIT legal anonymizer then it's not +really at all is not really concealing + + align:start position:0% +really at all is not really concealing + + + align:start position:0% +really at all is not really concealing +who they are but if you have a large + + align:start position:0% +who they are but if you have a large + + + align:start position:0% +who they are but if you have a large +number of different parties all using + + align:start position:0% +number of different parties all using + + + align:start position:0% +number of different parties all using +this then it actually can provide some + + align:start position:0% +this then it actually can provide some + + + align:start position:0% +this then it actually can provide some +privacy so we'll return one more time + + align:start position:0% +privacy so we'll return one more time + + + align:start position:0% +privacy so we'll return one more time +to how to resisting this kind of + + align:start position:0% +to how to resisting this kind of + + + align:start position:0% +to how to resisting this kind of +correlation attacks but for now let's + + align:start position:0% +correlation attacks but for now let's + + + align:start position:0% +correlation attacks but for now let's +say that we're not re resisting those + + align:start position:0% +say that we're not re resisting those + + + align:start position:0% +say that we're not re resisting those +correlation attacks and instead we're + + align:start position:0% +correlation attacks and instead we're + + + align:start position:0% +correlation attacks and instead we're +going to try to lower we assume that an + + align:start position:0% +going to try to lower we assume that an + + + align:start position:0% +going to try to lower we assume that an +attacker who sees both ends wins and + + align:start position:0% +attacker who sees both ends wins and + + + align:start position:0% +attacker who sees both ends wins and +we're trying to minimize the probability + + align:start position:0% +we're trying to minimize the probability + + + align:start position:0% +we're trying to minimize the probability +that that happens over + + align:start position:0% +that that happens over + + + align:start position:0% +that that happens over +time all right so I've just talked about + + align:start position:0% +time all right so I've just talked about + + + align:start position:0% +time all right so I've just talked about +message passing + + align:start position:0% +message passing + + + align:start position:0% +message passing +let's + + align:start position:0% +let's + + + align:start position:0% +let's +um well the way you would build that in + + align:start position:0% +um well the way you would build that in + + + align:start position:0% +um well the way you would build that in +something like a mix net is you give + + align:start position:0% +something like a mix net is you give + + + align:start position:0% +something like a mix net is you give +each of these relays a public key um K3 + + align:start position:0% +each of these relays a public key um K3 + + + align:start position:0% +each of these relays a public key um K3 +K2 K1 and when Ellis wants to send + + align:start position:0% +K2 K1 and when Ellis wants to send + + + align:start position:0% +K2 K1 and when Ellis wants to send +something through here she would say + + align:start position:0% +something through here she would say + + + align:start position:0% +something through here she would say +encrypt with + + align:start position:0% +encrypt with + + + align:start position:0% +encrypt with +K3 + + align:start position:0% + + + + align:start position:0% + +socks and then encrypt that with K2 + + align:start position:0% +socks and then encrypt that with K2 + + + align:start position:0% +socks and then encrypt that with K2 +I'm leaving off routing information for + + align:start position:0% +I'm leaving off routing information for + + + align:start position:0% +I'm leaving off routing information for +now and then encrypt with + + align:start position:0% +now and then encrypt with + + + align:start position:0% +now and then encrypt with +K1 but public key as you know is kind of + + align:start position:0% +K1 but public key as you know is kind of + + + align:start position:0% +K1 but public key as you know is kind of +expensive enough that you don't want to + + align:start position:0% +expensive enough that you don't want to + + + align:start position:0% +expensive enough that you don't want to +use it for bulk + + align:start position:0% +use it for bulk + + + align:start position:0% +use it for bulk +traffic so instead what you do and at + + align:start position:0% +traffic so instead what you do and at + + + align:start position:0% +traffic so instead what you do and at +this and if is right instead what you do + + align:start position:0% +this and if is right instead what you do + + + align:start position:0% +this and if is right instead what you do +is you negotiate a set of keys with each + + align:start position:0% +is you negotiate a set of keys with each + + + align:start position:0% +is you negotiate a set of keys with each +server so Alice shares a symmetric key + + align:start position:0% +server so Alice shares a symmetric key + + + align:start position:0% +server so Alice shares a symmetric key +with this relay a different symmetric + + align:start position:0% +with this relay a different symmetric + + + align:start position:0% +with this relay a different symmetric +key with this relay and a different + + align:start position:0% +key with this relay and a different + + + align:start position:0% +key with this relay and a different +symmetric key with this relay associate + + align:start position:0% +symmetric key with this relay associate + + + align:start position:0% +symmetric key with this relay associate +in what we call a circuit which is a + + align:start position:0% +in what we call a circuit which is a + + + align:start position:0% +in what we call a circuit which is a +path through the + + align:start position:0% +path through the + + + align:start position:0% +path through the +network + + align:start position:0% +network + + + align:start position:0% +network +and then and after the initial publicy + + align:start position:0% +and then and after the initial publicy + + + align:start position:0% +and then and after the initial publicy +set up to create those keys Alice can + + align:start position:0% +set up to create those keys Alice can + + + align:start position:0% +set up to create those keys Alice can +then use some Metro crypto to send stuff + + align:start position:0% +then use some Metro crypto to send stuff + + + align:start position:0% +then use some Metro crypto to send stuff +through the network if you stop at that + + align:start position:0% +through the network if you stop at that + + + align:start position:0% +through the network if you stop at that +point then you have onion routing as it + + align:start position:0% +point then you have onion routing as it + + + align:start position:0% +point then you have onion routing as it +was designed in the + + align:start position:0% +was designed in the + + + align:start position:0% +was designed in the +1990s by um cyers gold schlog and Reed I + + align:start position:0% +1990s by um cyers gold schlog and Reed I + + + align:start position:0% +1990s by um cyers gold schlog and Reed I +hope I'm getting the the names right um + + align:start position:0% +hope I'm getting the the names right um + + + align:start position:0% +hope I'm getting the the names right um +Paul cyers is still active the other two + + align:start position:0% +Paul cyers is still active the other two + + + align:start position:0% +Paul cyers is still active the other two +are working on other things + + align:start position:0% +are working on other things + + + align:start position:0% +are working on other things +um also once you've added circuits like + + align:start position:0% +um also once you've added circuits like + + + align:start position:0% +um also once you've added circuits like +that paths medium-term paths through the + + align:start position:0% +that paths medium-term paths through the + + + align:start position:0% +that paths medium-term paths through the +network you can have a easy reply + + align:start position:0% +network you can have a easy reply + + + align:start position:0% +network you can have a easy reply +Channel where things sent back this way + + align:start position:0% +Channel where things sent back this way + + + align:start position:0% +Channel where things sent back this way +get to Alice being encrypted at each + + align:start position:0% +get to Alice being encrypted at each + + + align:start position:0% +get to Alice being encrypted at each +step instead of decrypted at each + + align:start position:0% +step instead of decrypted at each + + + align:start position:0% +step instead of decrypted at each +step + + align:start position:0% +step + + + align:start position:0% +step +and of course you need some kind of + + align:start position:0% +and of course you need some kind of + + + align:start position:0% +and of course you need some kind of +Integrity checking either node by node + + align:start position:0% +Integrity checking either node by node + + + align:start position:0% +Integrity checking either node by node +or end to end because if you don't do + + align:start position:0% +or end to end because if you don't do + + + align:start position:0% +or end to end because if you don't do +Integrity checking then um well let's + + align:start position:0% +Integrity checking then um well let's + + + align:start position:0% +Integrity checking then um well let's +say uh let's say you're using a exor + + align:start position:0% +say uh let's say you're using a exor + + + align:start position:0% +say uh let's say you're using a exor +based stream Cipher for your encryption + + align:start position:0% +based stream Cipher for your encryption + + + align:start position:0% +based stream Cipher for your encryption +if you don't do Integrity checking then + + align:start position:0% +if you don't do Integrity checking then + + + align:start position:0% +if you don't do Integrity checking then +this node can exor in Alis Ellis Alis + + align:start position:0% +this node can exor in Alis Ellis Alis + + + align:start position:0% +this node can exor in Alis Ellis Alis +Alis Alis to the encrypted message and + + align:start position:0% +Alis Alis to the encrypted message and + + + align:start position:0% +Alis Alis to the encrypted message and +then when it is finally decrypted over + + align:start position:0% +then when it is finally decrypted over + + + align:start position:0% +then when it is finally decrypted over +here because that's a malleable crypto + + align:start position:0% +here because that's a malleable crypto + + + align:start position:0% +here because that's a malleable crypto +scheme + + align:start position:0% +scheme + + + align:start position:0% +scheme +if um if the + + align:start position:0% +if um if the + + + align:start position:0% +if um if the +same if the same node happens to if the + + align:start position:0% +same if the same node happens to if the + + + align:start position:0% +same if the same node happens to if the +same attacker is controlling this node + + align:start position:0% +same attacker is controlling this node + + + align:start position:0% +same attacker is controlling this node +as well or if the attacker is observing + + align:start position:0% +as well or if the attacker is observing + + + align:start position:0% +as well or if the attacker is observing +it here + + align:start position:0% +it here + + + align:start position:0% +it here +the attacker will see Alice Alis Alis + + align:start position:0% +the attacker will see Alice Alis Alis + + + align:start position:0% +the attacker will see Alice Alis Alis +Alis Alis exord with a reasonable plain + + align:start position:0% +Alis Alis exord with a reasonable plain + + + align:start position:0% +Alis Alis exord with a reasonable plain +text and be able to use that to identify + + align:start position:0% +text and be able to use that to identify + + + align:start position:0% +text and be able to use that to identify +ah this is the stream that came from + + align:start position:0% +ah this is the stream that came from + + + align:start position:0% +ah this is the stream that came from +Alice so let's do a little more on how + + align:start position:0% +Alice so let's do a little more on how + + + align:start position:0% +Alice so let's do a little more on how +the protocol works because it would be a + + align:start position:0% +the protocol works because it would be a + + + align:start position:0% +the protocol works because it would be a +shame to have everybody read the paper + + align:start position:0% +shame to have everybody read the paper + + + align:start position:0% +shame to have everybody read the paper +and then not talk about the stuff that + + align:start position:0% +and then not talk about the stuff that + + + align:start position:0% +and then not talk about the stuff that +the paper is focused + + align:start position:0% + + + + align:start position:0% + +on again I apologize for my Blackboard + + align:start position:0% +on again I apologize for my Blackboard + + + align:start position:0% +on again I apologize for my Blackboard +technique this is most of the time I'm + + align:start position:0% +technique this is most of the time I'm + + + align:start position:0% +technique this is most of the time I'm +sitting at home on the uh desktop I + + align:start position:0% +sitting at home on the uh desktop I + + + align:start position:0% +sitting at home on the uh desktop I +don't this is alien + + align:start position:0% +don't this is alien + + + align:start position:0% +don't this is alien +Tech + + align:start position:0% + + + + align:start position:0% + +so here's a relay here's + + align:start position:0% +so here's a relay here's + + + align:start position:0% +so here's a relay here's +Alice here's another + + align:start position:0% +Alice here's another + + + align:start position:0% +Alice here's another +relay here's Bob now one else wants to + + align:start position:0% +relay here's Bob now one else wants to + + + align:start position:0% +relay here's Bob now one else wants to +talk to + + align:start position:0% +talk to + + + align:start position:0% +talk to +Bob + + align:start position:0% +Bob + + + align:start position:0% +Bob +so first thing Alice has to do is build + + align:start position:0% +so first thing Alice has to do is build + + + align:start position:0% +so first thing Alice has to do is build +a circuit through these relays to Bob + + align:start position:0% +a circuit through these relays to Bob + + + align:start position:0% +a circuit through these relays to Bob +let's say she's picked these two R1 and + + align:start position:0% +let's say she's picked these two R1 and + + + align:start position:0% +let's say she's picked these two R1 and +R2 + + align:start position:0% +R2 + + + align:start position:0% +R2 +so Alis does first makes a TLS + + align:start position:0% +so Alis does first makes a TLS + + + align:start position:0% +so Alis does first makes a TLS +link to + + align:start position:0% +link to + + + align:start position:0% +link to +R1 R1 let's say already has a TLS link + + align:start position:0% +R1 R1 let's say already has a TLS link + + + align:start position:0% +R1 R1 let's say already has a TLS link +to + + align:start position:0% + + + + align:start position:0% + +R2 first thing Ellis does is she does an + + align:start position:0% +R2 first thing Ellis does is she does an + + + align:start position:0% +R2 first thing Ellis does is she does an +authenticated + + align:start position:0% +authenticated + + + align:start position:0% +authenticated +um a one-way authenticated one-way + + align:start position:0% +um a one-way authenticated one-way + + + align:start position:0% +um a one-way authenticated one-way +Anonymous key + + align:start position:0% +Anonymous key + + + align:start position:0% +Anonymous key +negotiation uh the old one in tour is + + align:start position:0% +negotiation uh the old one in tour is + + + align:start position:0% +negotiation uh the old one in tour is +called tap the new one is called entor + + align:start position:0% +called tap the new one is called entor + + + align:start position:0% +called tap the new one is called entor +they both have + + align:start position:0% + + + + align:start position:0% + +proofs they both even have correct + + align:start position:0% +proofs they both even have correct + + + align:start position:0% +proofs they both even have correct +proofs although the original proof in + + align:start position:0% +proofs although the original proof in + + + align:start position:0% +proofs although the original proof in +the paper was had a flaw in + + align:start position:0% +the paper was had a flaw in + + + align:start position:0% +the paper was had a flaw in +it but when that's done you know she + + align:start position:0% +it but when that's done you know she + + + align:start position:0% +it but when that's done you know she +basically sends a create she sends a + + align:start position:0% +basically sends a create she sends a + + + align:start position:0% +basically sends a create she sends a +create cell and she picks a circuit ID + + align:start position:0% +create cell and she picks a circuit ID + + + align:start position:0% +create cell and she picks a circuit ID +let's say she picks + + align:start position:0% +let's say she picks + + + align:start position:0% +let's say she picks +three and says create + + align:start position:0% +three and says create + + + align:start position:0% +three and says create +three the relay says created + + align:start position:0% + + + + align:start position:0% + +and now R1 and Ellis share a secret key + + align:start position:0% +and now R1 and Ellis share a secret key + + + align:start position:0% +and now R1 and Ellis share a secret key +which I'm going which a symmetric key + + align:start position:0% +which I'm going which a symmetric key + + + align:start position:0% +which I'm going which a symmetric key +which I'm going to call + + align:start position:0% + + + + align:start position:0% + +S1 and they both have this stored as as + + align:start position:0% +S1 and they both have this stored as as + + + align:start position:0% +S1 and they both have this stored as as +three with respect to this + + align:start position:0% + + + + align:start position:0% + +link now Ellis can use that key to send + + align:start position:0% +link now Ellis can use that key to send + + + align:start position:0% +link now Ellis can use that key to send +messages to R1 so she says on three + + align:start position:0% +messages to R1 so she says on three + + + align:start position:0% +messages to R1 so she says on three +that's the circuit ID that everything + + align:start position:0% +that's the circuit ID that everything + + + align:start position:0% +that's the circuit ID that everything +was talking about in the paper send a + + align:start position:0% +was talking about in the paper send a + + + align:start position:0% +was talking about in the paper send a +send a relay + + align:start position:0% + + + + align:start position:0% + +extend with some contents um the extend + + align:start position:0% +extend with some contents um the extend + + + align:start position:0% +extend with some contents um the extend +cell basically contains the first half + + align:start position:0% +cell basically contains the first half + + + align:start position:0% +cell basically contains the first half +of the create + + align:start position:0% +of the create + + + align:start position:0% +of the create +handshake but this time it's not + + align:start position:0% +handshake but this time it's not + + + align:start position:0% +handshake but this time it's not +encrypted with r1's public key it's + + align:start position:0% +encrypted with r1's public key it's + + + align:start position:0% +encrypted with r1's public key it's +encrypted with r2's public key and it + + align:start position:0% +encrypted with r2's public key and it + + + align:start position:0% +encrypted with r2's public key and it +also says and this one goes to R2 so R1 + + align:start position:0% +also says and this one goes to R2 so R1 + + + align:start position:0% +also says and this one goes to R2 so R1 +knows to open + + align:start position:0% +knows to open + + + align:start position:0% +knows to open +a new circuit to R2 it says + + align:start position:0% + + + + align:start position:0% + +create and it passes the initial part of + + align:start position:0% +create and it passes the initial part of + + + align:start position:0% +create and it passes the initial part of +the handshake as it came from Alice + + align:start position:0% +the handshake as it came from Alice + + + align:start position:0% +the handshake as it came from Alice +along and it picks the own its own + + align:start position:0% +along and it picks the own its own + + + align:start position:0% +along and it picks the own its own +circuit ID because Al the circuit IDs + + align:start position:0% +circuit ID because Al the circuit IDs + + + align:start position:0% +circuit ID because Al the circuit IDs +identify the different circuits on this + + align:start position:0% +identify the different circuits on this + + + align:start position:0% +identify the different circuits on this +TLS connection and Alice doesn't know + + align:start position:0% +TLS connection and Alice doesn't know + + + align:start position:0% +TLS connection and Alice doesn't know +what other circuit IDs are in use on + + align:start position:0% +what other circuit IDs are in use on + + + align:start position:0% +what other circuit IDs are in use on +this one because this one is private to + + align:start position:0% +this one because this one is private to + + + align:start position:0% +this one because this one is private to +R1 and R2 so it might pick like 95 + + align:start position:0% +R1 and R2 so it might pick like 95 + + + align:start position:0% +R1 and R2 so it might pick like 95 +it actually is very unlikely to pick + + align:start position:0% +it actually is very unlikely to pick + + + align:start position:0% +it actually is very unlikely to pick +that because they're randomly chosen + + align:start position:0% +that because they're randomly chosen + + + align:start position:0% +that because they're randomly chosen +from a 4 byte key from a 4 byte space + + align:start position:0% +from a 4 byte key from a 4 byte space + + + align:start position:0% +from a 4 byte key from a 4 byte space +but I don't want to write out any 32-bit + + align:start position:0% +but I don't want to write out any 32-bit + + + align:start position:0% +but I don't want to write out any 32-bit +numbers + + align:start position:0% +numbers + + + align:start position:0% +numbers +today and this says created in response + + align:start position:0% +today and this says created in response + + + align:start position:0% +today and this says created in response +so this one sends back extended + + align:start position:0% +so this one sends back extended + + + align:start position:0% +so this one sends back extended +encrypted with S1 and now + + align:start position:0% + + + + align:start position:0% + +Alice and relay 2 Share S2 + + align:start position:0% +Alice and relay 2 Share S2 + + + align:start position:0% +Alice and relay 2 Share S2 +so now Al sends a me can send messages + + align:start position:0% +so now Al sends a me can send messages + + + align:start position:0% +so now Al sends a me can send messages +encrypted first with S2 and then with S1 + + align:start position:0% +encrypted first with S2 and then with S1 + + + align:start position:0% +encrypted first with S2 and then with S1 +as relay cells so she sends a message + + align:start position:0% +as relay cells so she sends a message + + + align:start position:0% +as relay cells so she sends a message +like that R1 removes the + + align:start position:0% +like that R1 removes the + + + align:start position:0% +like that R1 removes the +S1 encryption and forwards it on it says + + align:start position:0% +S1 encryption and forwards it on it says + + + align:start position:0% +S1 encryption and forwards it on it says +okay it came in on three uh it came in + + align:start position:0% +okay it came in on three uh it came in + + + align:start position:0% +okay it came in on three uh it came in +on circuit three I know that three goes + + align:start position:0% +on circuit three I know that three goes + + + align:start position:0% +on circuit three I know that three goes +to 95 on this one so I sent it on 95 and + + align:start position:0% +to 95 on this one so I sent it on 95 and + + + align:start position:0% +to 95 on this one so I sent it on 95 and +I say whatever I got after decrypting + + align:start position:0% +I say whatever I got after decrypting + + + align:start position:0% +I say whatever I got after decrypting +okay and this one says Ah I came on 95 + + align:start position:0% +okay and this one says Ah I came on 95 + + + align:start position:0% +okay and this one says Ah I came on 95 +95 corresponds to the shared key S2 so + + align:start position:0% +95 corresponds to the shared key S2 so + + + align:start position:0% +95 corresponds to the shared key S2 so +I'll decrypt with that oh that says open + + align:start position:0% +I'll decrypt with that oh that says open + + + align:start position:0% +I'll decrypt with that oh that says open +a connection to Bob and relay 2 opens a + + align:start position:0% +a connection to Bob and relay 2 opens a + + + align:start position:0% +a connection to Bob and relay 2 opens a +TCP connection to Bob and tells Ellis + + align:start position:0% +TCP connection to Bob and tells Ellis + + + align:start position:0% +TCP connection to Bob and tells Ellis +that it did it through the same process + + align:start position:0% +that it did it through the same process + + + align:start position:0% +that it did it through the same process +and ell says great tell Bob um H H tell + + align:start position:0% +and ell says great tell Bob um H H tell + + + align:start position:0% +and ell says great tell Bob um H H tell +Bob + + align:start position:0% +Bob + + + align:start position:0% +Bob +http1 get/ + + align:start position:0% +http1 get/ + + + align:start position:0% +http1 get/ +index.html and the world goes on now + + align:start position:0% +index.html and the world goes on now + + + align:start position:0% +index.html and the world goes on now +let's see what did I leave out oh skip + + align:start position:0% +let's see what did I leave out oh skip + + + align:start position:0% +let's see what did I leave out oh skip +that skip that skip that um so what do + + align:start position:0% +that skip that skip that um so what do + + + align:start position:0% +that skip that skip that um so what do +we actually relay some designs in this + + align:start position:0% +we actually relay some designs in this + + + align:start position:0% +we actually relay some designs in this +area say well you should send IP packets + + align:start position:0% +area say well you should send IP packets + + + align:start position:0% +area say well you should send IP packets +back and forth this should just be a way + + align:start position:0% +back and forth this should just be a way + + + align:start position:0% +back and forth this should just be a way +to transmit IP packets one of the + + align:start position:0% +to transmit IP packets one of the + + + align:start position:0% +to transmit IP packets one of the +problems with that + + align:start position:0% +problems with that + + + align:start position:0% +problems with that +is we want to support as many users as + + align:start position:0% +is we want to support as many users as + + + align:start position:0% +is we want to support as many users as +possible which means that we have to run + + align:start position:0% +possible which means that we have to run + + + align:start position:0% +possible which means that we have to run +on all kinds of operating systems and + + align:start position:0% +on all kinds of operating systems and + + + align:start position:0% +on all kinds of operating systems and +operating systems TCP Stacks do not act + + align:start position:0% +operating systems TCP Stacks do not act + + + align:start position:0% +operating systems TCP Stacks do not act +anything like each other if you've ever + + align:start position:0% +anything like each other if you've ever + + + align:start position:0% +anything like each other if you've ever +used nmap or if you've ever used any + + align:start position:0% +used nmap or if you've ever used any + + + align:start position:0% +used nmap or if you've ever used any +kind of network traffic analysis tool + + align:start position:0% +kind of network traffic analysis tool + + + align:start position:0% +kind of network traffic analysis tool +you can trivially tell Windows T CP from + + align:start position:0% +you can trivially tell Windows T CP from + + + align:start position:0% +you can trivially tell Windows T CP from +FreeBSD from Linux TCP and you can even + + align:start position:0% +FreeBSD from Linux TCP and you can even + + + align:start position:0% +FreeBSD from Linux TCP and you can even +held different versions apart and + + align:start position:0% +held different versions apart and + + + align:start position:0% +held different versions apart and +moreover if you can send raw IP packets + + align:start position:0% +moreover if you can send raw IP packets + + + align:start position:0% +moreover if you can send raw IP packets +to to a chosen host you can provoke + + align:start position:0% +to to a chosen host you can provoke + + + align:start position:0% +to to a chosen host you can provoke +different + + align:start position:0% +different + + + align:start position:0% +different +responses you know in part be in part + + align:start position:0% +responses you know in part be in part + + + align:start position:0% +responses you know in part be in part +based on what the host is doing so if + + align:start position:0% +based on what the host is doing so if + + + align:start position:0% +based on what the host is doing so if +you're doing IP you would actually need + + align:start position:0% +you're doing IP you would actually need + + + align:start position:0% +you're doing IP you would actually need +an IP normalization layer if IP is what + + align:start position:0% +an IP normalization layer if IP is what + + + align:start position:0% +an IP normalization layer if IP is what +you transport back and forth + + align:start position:0% +you transport back and forth + + + align:start position:0% +you transport back and forth +and it seems that anything less than a + + align:start position:0% +and it seems that anything less than a + + + align:start position:0% +and it seems that anything less than a +full IP stack is not actually going to + + align:start position:0% +full IP stack is not actually going to + + + align:start position:0% +full IP stack is not actually going to +work for IP normalization so you + + align:start position:0% +work for IP normalization so you + + + align:start position:0% +work for IP normalization so you +wouldn't want to do + + align:start position:0% +wouldn't want to do + + + align:start position:0% +wouldn't want to do +that instead what we just chose is and + + align:start position:0% +that instead what we just chose is and + + + align:start position:0% +that instead what we just chose is and +this is largely because this is the + + align:start position:0% +this is largely because this is the + + + align:start position:0% +this is largely because this is the +easiest way you take the contents of TCP + + align:start position:0% +easiest way you take the contents of TCP + + + align:start position:0% +easiest way you take the contents of TCP +streams so you just say so you assume + + align:start position:0% +streams so you just say so you assume + + + align:start position:0% +streams so you just say so you assume +each of these things is reliable and in + + align:start position:0% +each of these things is reliable and in + + + align:start position:0% +each of these things is reliable and in +order you + + align:start position:0% +order you + + + align:start position:0% +order you +have the computer at Al's and the + + align:start position:0% +have the computer at Al's and the + + + align:start position:0% +have the computer at Al's and the +program alysis running to do all of this + + align:start position:0% +program alysis running to do all of this + + + align:start position:0% +program alysis running to do all of this +stuff or + + align:start position:0% +stuff or + + + align:start position:0% +stuff or +her except TCP connections from Alice's + + align:start position:0% +her except TCP connections from Alice's + + + align:start position:0% +her except TCP connections from Alice's +applications and then just relay their + + align:start position:0% +applications and then just relay their + + + align:start position:0% +applications and then just relay their +contents and don't do anything trickier + + align:start position:0% +contents and don't do anything trickier + + + align:start position:0% +contents and don't do anything trickier +on the network level you might be able + + align:start position:0% +on the network level you might be able + + + align:start position:0% +on the network level you might be able +to get better performance by trying some + + align:start position:0% +to get better performance by trying some + + + align:start position:0% +to get better performance by trying some +other means and there were some papers + + align:start position:0% +other means and there were some papers + + + align:start position:0% +other means and there were some papers +examining how you would do that but this + + align:start position:0% +examining how you would do that but this + + + align:start position:0% +examining how you would do that but this +is the one that we could actually + + align:start position:0% +is the one that we could actually + + + align:start position:0% +is the one that we could actually +Implement because we paid a lot more + + align:start position:0% +Implement because we paid a lot more + + + align:start position:0% +Implement because we paid a lot more +attention in security and compilers + + align:start position:0% +attention in security and compilers + + + align:start position:0% +attention in security and compilers +classes than we did in networking + + align:start position:0% +classes than we did in networking + + + align:start position:0% +classes than we did in networking +classes + + align:start position:0% +classes + + + align:start position:0% +classes +um now we have networking people but in + + align:start position:0% +um now we have networking people but in + + + align:start position:0% +um now we have networking people but in +in 2003 2004 we did not have any + + align:start position:0% +in 2003 2004 we did not have any + + + align:start position:0% +in 2003 2004 we did not have any +networking + + align:start position:0% +networking + + + align:start position:0% +networking +experts um TCP also seems like the right + + align:start position:0% +experts um TCP also seems like the right + + + align:start position:0% +experts um TCP also seems like the right +level higher level protocols like you + + align:start position:0% +level higher level protocols like you + + + align:start position:0% +level higher level protocols like you +might in some of the original un writing + + align:start position:0% +might in some of the original un writing + + + align:start position:0% +might in some of the original un writing +designs there were separate proxies at + + align:start position:0% +designs there were separate proxies at + + + align:start position:0% +designs there were separate proxies at +this end for HTTP for FTP and so on that + + align:start position:0% +this end for HTTP for FTP and so on that + + + align:start position:0% +this end for HTTP for FTP and so on that +seems to be mostly a bad idea because + + align:start position:0% +seems to be mostly a bad idea because + + + align:start position:0% +seems to be mostly a bad idea because +any interesting protocol is going to + + align:start position:0% +any interesting protocol is going to + + + align:start position:0% +any interesting protocol is going to +have end to-end encryption from Alis all + + align:start position:0% +have end to-end encryption from Alis all + + + align:start position:0% +have end to-end encryption from Alis all +the way to Bob that is if we're lucky + + align:start position:0% +the way to Bob that is if we're lucky + + + align:start position:0% +the way to Bob that is if we're lucky +Alice is doing a TLS connection over + + align:start position:0% +Alice is doing a TLS connection over + + + align:start position:0% +Alice is doing a TLS connection over +this to + + align:start position:0% +this to + + + align:start position:0% +this to +Bob so so that um TLS properties get her + + align:start position:0% +Bob so so that um TLS properties get her + + + align:start position:0% +Bob so so that um TLS properties get her +integrity and um + + align:start position:0% +integrity and um + + + align:start position:0% +integrity and um +secrecy but if that's the case then any + + align:start position:0% +secrecy but if that's the case then any + + + align:start position:0% +secrecy but if that's the case then any +kind of anonymizing Transformations you + + align:start position:0% +kind of anonymizing Transformations you + + + align:start position:0% +kind of anonymizing Transformations you +want to apply to the encrypted data need + + align:start position:0% +want to apply to the encrypted data need + + + align:start position:0% +want to apply to the encrypted data need +to happen in the application Alice is + + align:start position:0% +to happen in the application Alice is + + + align:start position:0% +to happen in the application Alice is +using before the TLs happens + + align:start position:0% +using before the TLs happens + + + align:start position:0% +using before the TLs happens +entirely so you can't really do that in + + align:start position:0% +entirely so you can't really do that in + + + align:start position:0% +entirely so you can't really do that in +a proxy and that's kind of why we came + + align:start position:0% +a proxy and that's kind of why we came + + + align:start position:0% +a proxy and that's kind of why we came +out to okay The Sweet Spot is TCP + + align:start position:0% +out to okay The Sweet Spot is TCP + + + align:start position:0% +out to okay The Sweet Spot is TCP +contents somebody asked me okay but + + align:start position:0% +contents somebody asked me okay but + + + align:start position:0% +contents somebody asked me okay but +where are your security proofs um we do + + align:start position:0% +where are your security proofs um we do + + + align:start position:0% +where are your security proofs um we do +have security proofs for a lot of the + + align:start position:0% +have security proofs for a lot of the + + + align:start position:0% +have security proofs for a lot of the +cryptography that we + + align:start position:0% +cryptography that we + + + align:start position:0% +cryptography that we +use um you know stand standard + + align:start position:0% +use um you know stand standard + + + align:start position:0% +use um you know stand standard +reductions for the protocol as a + + align:start position:0% +reductions for the protocol as a + + + align:start position:0% +reductions for the protocol as a +whole there are proofs in the field + + align:start position:0% +whole there are proofs in the field + + + align:start position:0% +whole there are proofs in the field +about certain aspects of onion routing + + align:start position:0% +about certain aspects of onion routing + + + align:start position:0% +about certain aspects of onion routing +but the models that they have to use in + + align:start position:0% +but the models that they have to use in + + + align:start position:0% +but the models that they have to use in +order to prove this + + align:start position:0% +order to prove this + + + align:start position:0% +order to prove this +provides + + align:start position:0% +provides + + + align:start position:0% +provides +anonymity make assumptions + + align:start position:0% +anonymity make assumptions + + + align:start position:0% +anonymity make assumptions +about the universe the network and the + + align:start position:0% +about the universe the network and the + + + align:start position:0% +about the universe the network and the +attacker's abilities that + + align:start position:0% +attacker's abilities that + + + align:start position:0% +attacker's abilities that +are so weird as to satisfy no one but + + align:start position:0% +are so weird as to satisfy no one but + + + align:start position:0% +are so weird as to satisfy no one but +certain program Committees of more + + align:start position:0% +certain program Committees of more + + + align:start position:0% +certain program Committees of more +theoretical + + align:start position:0% +theoretical + + + align:start position:0% +theoretical +conferences I mean the kind of things + + align:start position:0% +conferences I mean the kind of things + + + align:start position:0% +conferences I mean the kind of things +you can prove is that an attacker who + + align:start position:0% +you can prove is that an attacker who + + + align:start position:0% +you can prove is that an attacker who +sees this who sees a number of strings + + align:start position:0% +sees this who sees a number of strings + + + align:start position:0% +sees this who sees a number of strings +of of this this length but doesn't get + + align:start position:0% +of of this this length but doesn't get + + + align:start position:0% +of of this this length but doesn't get +to see who sees a number of streams here + + align:start position:0% +to see who sees a number of streams here + + + align:start position:0% +to see who sees a number of streams here +all of equal volume and equal timing + + align:start position:0% +all of equal volume and equal timing + + + align:start position:0% +all of equal volume and equal timing +cannot tell which one goes to which Bob + + align:start position:0% +cannot tell which one goes to which Bob + + + align:start position:0% +cannot tell which one goes to which Bob +simply by looking at the bites coming + + align:start position:0% +simply by looking at the bites coming + + + align:start position:0% +simply by looking at the bites coming +out but that's hardly a useful + + align:start position:0% +out but that's hardly a useful + + + align:start position:0% +out but that's hardly a useful +result also the kind of guarantees you + + align:start position:0% +result also the kind of guarantees you + + + align:start position:0% +result also the kind of guarantees you +can get from anonymity systems that we + + align:start position:0% +can get from anonymity systems that we + + + align:start position:0% +can get from anonymity systems that we +know how to build + + align:start position:0% +know how to build + + + align:start position:0% +know how to build +today okay I should be careful here + + align:start position:0% +today okay I should be careful here + + + align:start position:0% +today okay I should be careful here +there are some where you have very + + align:start position:0% +there are some where you have very + + + align:start position:0% +there are some where you have very +strong guarantees that we do know how to + + align:start position:0% +strong guarantees that we do know how to + + + align:start position:0% +strong guarantees that we do know how to +build that you would never actually want + + align:start position:0% +build that you would never actually want + + + align:start position:0% +build that you would never actually want +to use + + align:start position:0% +to use + + + align:start position:0% +to use +like um classical chian D DC nets for + + align:start position:0% +like um classical chian D DC nets for + + + align:start position:0% +like um classical chian D DC nets for +instance provide guaranteed anonymity + + align:start position:0% +instance provide guaranteed anonymity + + + align:start position:0% +instance provide guaranteed anonymity +except any participant can shut down the + + align:start position:0% +except any participant can shut down the + + + align:start position:0% +except any participant can shut down the +whole network by not participating that + + align:start position:0% +whole network by not participating that + + + align:start position:0% +whole network by not participating that +does not scale but for the things that + + align:start position:0% +does not scale but for the things that + + + align:start position:0% +does not scale but for the things that +we do want to build these days what for + + align:start position:0% +we do want to build these days what for + + + align:start position:0% +we do want to build these days what for +the most part you cannot the anonymity + + align:start position:0% +the most part you cannot the anonymity + + + align:start position:0% +the most part you cannot the anonymity +properties are + + align:start position:0% +properties are + + + align:start position:0% +properties are +probabilistic rather than categorically + + align:start position:0% +probabilistic rather than categorically + + + align:start position:0% +probabilistic rather than categorically +guarantee so instead of saying instead + + align:start position:0% +guarantee so instead of saying instead + + + align:start position:0% +guarantee so instead of saying instead +of asking does this protect Alice the + + align:start position:0% +of asking does this protect Alice the + + + align:start position:0% +of asking does this protect Alice the +kind of questions you can ask are under + + align:start position:0% +kind of questions you can ask are under + + + align:start position:0% +kind of questions you can ask are under +this Asser assumption about attacker + + align:start position:0% +this Asser assumption about attacker + + + align:start position:0% +this Asser assumption about attacker +capabilities how much traffic can Alice + + align:start position:0% +capabilities how much traffic can Alice + + + align:start position:0% +capabilities how much traffic can Alice +safely send if she wants a 99% chance of + + align:start position:0% +safely send if she wants a 99% chance of + + + align:start position:0% +safely send if she wants a 99% chance of +not being linked to her + + align:start position:0% +not being linked to her + + + align:start position:0% +not being linked to her +activities so right will anyone actually + + align:start position:0% +activities so right will anyone actually + + + align:start position:0% +activities so right will anyone actually +run these things that was an opening + + align:start position:0% +run these things that was an opening + + + align:start position:0% +run these things that was an opening +question when we started we didn't know + + align:start position:0% +question when we started we didn't know + + + align:start position:0% +question when we started we didn't know +whether the system would actually take + + align:start position:0% +whether the system would actually take + + + align:start position:0% +whether the system would actually take +off or not so the only way to actually + + align:start position:0% +off or not so the only way to actually + + + align:start position:0% +off or not so the only way to actually +find out was proof + + align:start position:0% +find out was proof + + + align:start position:0% +find out was proof +by try it see what happens um we got + + align:start position:0% +by try it see what happens um we got + + + align:start position:0% +by try it see what happens um we got +some a fair amount of of volunteer + + align:start position:0% +some a fair amount of of volunteer + + + align:start position:0% +some a fair amount of of volunteer +operators a fair number of nonprofits + + align:start position:0% +operators a fair number of nonprofits + + + align:start position:0% +operators a fair number of nonprofits +have formed whose sole purpose is just + + align:start position:0% +have formed whose sole purpose is just + + + align:start position:0% +have formed whose sole purpose is just +to take donations and use them to buy + + align:start position:0% +to take donations and use them to buy + + + align:start position:0% +to take donations and use them to buy +bandwidth and Run Tour + + align:start position:0% +bandwidth and Run Tour + + + align:start position:0% +bandwidth and Run Tour +nodes and there are also universities + + align:start position:0% +nodes and there are also universities + + + align:start position:0% +nodes and there are also universities +there's also you know private companies + + align:start position:0% +there's also you know private companies + + + align:start position:0% +there's also you know private companies +for a while aamai was running a tour + + align:start position:0% +for a while aamai was running a tour + + + align:start position:0% +for a while aamai was running a tour +server um out of their security team + + align:start position:0% +server um out of their security team + + + align:start position:0% +server um out of their security team +because they thought it was fun + + align:start position:0% +because they thought it was fun + + + align:start position:0% +because they thought it was fun +um the legal issues there again I'm not + + align:start position:0% +um the legal issues there again I'm not + + + align:start position:0% +um the legal issues there again I'm not +a lawyer I can't offer legal advice but + + align:start position:0% +a lawyer I can't offer legal advice but + + + align:start position:0% +a lawyer I can't offer legal advice but +five different people ask about legal + + align:start position:0% +five different people ask about legal + + + align:start position:0% +five different people ask about legal +issues + + align:start position:0% +issues + + + align:start position:0% +issues +um as far as I can tell in the US at + + align:start position:0% +um as far as I can tell in the US at + + + align:start position:0% +um as far as I can tell in the US at +least there's no legal impediment to + + align:start position:0% +least there's no legal impediment to + + + align:start position:0% +least there's no legal impediment to +running a tour server and that seems to + + align:start position:0% +running a tour server and that seems to + + + align:start position:0% +running a tour server and that seems to +be the case throughout most of Europe as + + align:start position:0% +be the case throughout most of Europe as + + + align:start position:0% +be the case throughout most of Europe as +far as I'm aware in in places that + + align:start position:0% +far as I'm aware in in places that + + + align:start position:0% +far as I'm aware in in places that +generally have less internet Freedom + + align:start position:0% +generally have less internet Freedom + + + align:start position:0% +generally have less internet Freedom +it's a dice your proposition the issues + + align:start position:0% +it's a dice your proposition the issues + + + align:start position:0% +it's a dice your proposition the issues +to be concerned about are not is it + + align:start position:0% +to be concerned about are not is it + + + align:start position:0% +to be concerned about are not is it +illegal to run a tour server + + align:start position:0% +illegal to run a tour server + + + align:start position:0% +illegal to run a tour server +but if I tell if somebody does something + + align:start position:0% +but if I tell if somebody does something + + + align:start position:0% +but if I tell if somebody does something +illegal or undesirable with my tour + + align:start position:0% +illegal or undesirable with my tour + + + align:start position:0% +illegal or undesirable with my tour +server will my ISP shut me down + + align:start position:0% +server will my ISP shut me down + + + align:start position:0% +server will my ISP shut me down +and will my and will law enforcement + + align:start position:0% +and will my and will law enforcement + + + align:start position:0% +and will my and will law enforcement +believe oh you're just running a tour + + align:start position:0% +believe oh you're just running a tour + + + align:start position:0% +believe oh you're just running a tour +server or will they seize the computer + + align:start position:0% +server or will they seize the computer + + + align:start position:0% +server or will they seize the computer +to make sure um for those I would + + align:start position:0% +to make sure um for those I would + + + align:start position:0% +to make sure um for those I would +suggest not running a tour server out of + + align:start position:0% +suggest not running a tour server out of + + + align:start position:0% +suggest not running a tour server out of +your dorm + + align:start position:0% +your dorm + + + align:start position:0% +your dorm +room oh excuse me don't run an exit out + + align:start position:0% +room oh excuse me don't run an exit out + + + align:start position:0% +room oh excuse me don't run an exit out +of your door room dorm room a relay out + + align:start position:0% +of your door room dorm room a relay out + + + align:start position:0% +of your door room dorm room a relay out +of your dorm room assuming that Network + + align:start position:0% +of your dorm room assuming that Network + + + align:start position:0% +of your dorm room assuming that Network +policy allows that I think it I have no + + align:start position:0% +policy allows that I think it I have no + + + align:start position:0% +policy allows that I think it I have no +idea um they've changed so much since I + + align:start position:0% +idea um they've changed so much since I + + + align:start position:0% +idea um they've changed so much since I +was a kid um + + align:start position:0% +was a kid um + + + align:start position:0% +was a kid um +have um running an exit out of your dorm + + align:start position:0% +have um running an exit out of your dorm + + + align:start position:0% +have um running an exit out of your dorm +room could get you in trouble + + align:start position:0% +room could get you in trouble + + + align:start position:0% +room could get you in trouble +um but running running a non-exit relay + + align:start position:0% +um but running running a non-exit relay + + + align:start position:0% +um but running running a non-exit relay +that doesn't deliver traffic to the + + align:start position:0% +that doesn't deliver traffic to the + + + align:start position:0% +that doesn't deliver traffic to the +internet is is is less likely to create + + align:start position:0% +internet is is is less likely to create + + + align:start position:0% +internet is is is less likely to create +those issues in + + align:start position:0% +those issues in + + + align:start position:0% +those issues in +particular the likeliest but you know if + + align:start position:0% +particular the likeliest but you know if + + + align:start position:0% +particular the likeliest but you know if +you do it in a nice Colo site and you + + align:start position:0% +you do it in a nice Colo site and you + + + align:start position:0% +you do it in a nice Colo site and you +get your isp's permission then it's + + align:start position:0% +get your isp's permission then it's + + + align:start position:0% +get your isp's permission then it's +pretty reasonable thing to do let's see + + align:start position:0% +pretty reasonable thing to do let's see + + + align:start position:0% +pretty reasonable thing to do let's see +um someone asked well what if users + + align:start position:0% +um someone asked well what if users + + + align:start position:0% +um someone asked well what if users +don't trust a particular node and this + + align:start position:0% +don't trust a particular node and this + + + align:start position:0% +don't trust a particular node and this +brings me to my next question the my + + align:start position:0% +brings me to my next question the my + + + align:start position:0% +brings me to my next question the my +next topic so the software that clients + + align:start position:0% +next topic so the software that clients + + + align:start position:0% +next topic so the software that clients +use you can tell it don't use this one + + align:start position:0% +use you can tell it don't use this one + + + align:start position:0% +use you can tell it don't use this one +don't use this one only use this one but + + align:start position:0% +don't use this one only use this one but + + + align:start position:0% +don't use this one only use this one but +remember that anonymity loves company + + align:start position:0% +remember that anonymity loves company + + + align:start position:0% +remember that anonymity loves company +principle if I'm the if I am using every + + align:start position:0% +principle if I'm the if I am using every + + + align:start position:0% +principle if I'm the if I am using every +no if I'm only using three nodes and + + align:start position:0% +no if I'm only using three nodes and + + + align:start position:0% +no if I'm only using three nodes and +you're using three different nodes and + + align:start position:0% +you're using three different nodes and + + + align:start position:0% +you're using three different nodes and +you're using three different nodes our + + align:start position:0% +you're using three different nodes our + + + align:start position:0% +you're using three different nodes our +traffic will not mix at all to the + + align:start position:0% +traffic will not mix at all to the + + + align:start position:0% +traffic will not mix at all to the +extent that we partition off which parts + + align:start position:0% +extent that we partition off which parts + + + align:start position:0% +extent that we partition off which parts +of the network we use we are + + align:start position:0% +of the network we use we are + + + align:start position:0% +of the network we use we are +distinguishable from one another now if + + align:start position:0% +distinguishable from one another now if + + + align:start position:0% +distinguishable from one another now if +I just exclude one or two no and you + + align:start position:0% +I just exclude one or two no and you + + + align:start position:0% +I just exclude one or two no and you +just exclude one or two nodes that's not + + align:start position:0% +just exclude one or two nodes that's not + + + align:start position:0% +just exclude one or two nodes that's not +a big partitioning and that doesn't help + + align:start position:0% +a big partitioning and that doesn't help + + + align:start position:0% +a big partitioning and that doesn't help +distinguishability that much + + align:start position:0% +distinguishability that much + + + align:start position:0% +distinguishability that much +but it would be good to the extent + + align:start position:0% +but it would be good to the extent + + + align:start position:0% +but it would be good to the extent +possible to have everyone using the same + + align:start position:0% +possible to have everyone using the same + + + align:start position:0% +possible to have everyone using the same +nodes so right how do we accomplish that + + align:start position:0% +nodes so right how do we accomplish that + + + align:start position:0% +nodes so right how do we accomplish that +so version one in the first version of + + align:start position:0% +so version one in the first version of + + + align:start position:0% +so version one in the first version of +Tor we just chipped a list of all of the + + align:start position:0% +Tor we just chipped a list of all of the + + + align:start position:0% +Tor we just chipped a list of all of the +nodes I think there were three of them + + align:start position:0% +nodes I think there were three of them + + + align:start position:0% +nodes I think there were three of them +or five or something now I think there + + align:start position:0% +or five or something now I think there + + + align:start position:0% +or five or something now I think there +were about six of which three were all + + align:start position:0% +were about six of which three were all + + + align:start position:0% +were about six of which three were all +running on the same computer in a closet + + align:start position:0% +running on the same computer in a closet + + + align:start position:0% +running on the same computer in a closet +at LCS and Tech + + align:start position:0% +at LCS and Tech + + + align:start position:0% +at LCS and Tech +Square um all right so that wasn't a + + align:start position:0% +Square um all right so that wasn't a + + + align:start position:0% +Square um all right so that wasn't a +good idea because nodes can go up and + + align:start position:0% +good idea because nodes can go up and + + + align:start position:0% +good idea because nodes can go up and +down noes change you don't want to have + + align:start position:0% +down noes change you don't want to have + + + align:start position:0% +down noes change you don't want to have +to put out a new release of your + + align:start position:0% +to put out a new release of your + + + align:start position:0% +to put out a new release of your +software every time somebody joins and + + align:start position:0% +software every time somebody joins and + + + align:start position:0% +software every time somebody joins and +leaves the network so you could just + + align:start position:0% +leaves the network so you could just + + + align:start position:0% +leaves the network so you could just +have every node keep a list of all the + + align:start position:0% +have every node keep a list of all the + + + align:start position:0% +have every node keep a list of all the +other nodes that are connected to it and + + align:start position:0% +other nodes that are connected to it and + + + align:start position:0% +other nodes that are connected to it and +all advertise to each other and then + + align:start position:0% +all advertise to each other and then + + + align:start position:0% +all advertise to each other and then +when a client connects to a client just + + align:start position:0% +when a client connects to a client just + + + align:start position:0% +when a client connects to a client just +has to know one node and then says hey + + align:start position:0% +has to know one node and then says hey + + + align:start position:0% +has to know one node and then says hey +who's on the network and actually a lot + + align:start position:0% +who's on the network and actually a lot + + + align:start position:0% +who's on the network and actually a lot +of designs people have built work this + + align:start position:0% +of designs people have built work this + + + align:start position:0% +of designs people have built work this +way a lot of early peer-to-peer + + align:start position:0% +way a lot of early peer-to-peer + + + align:start position:0% +way a lot of early peer-to-peer +anonymity designs that work this way but + + align:start position:0% +anonymity designs that work this way but + + + align:start position:0% +anonymity designs that work this way but +it's a terrible idea because if you go + + align:start position:0% +it's a terrible idea because if you go + + + align:start position:0% +it's a terrible idea because if you go +to one node and say who's on the network + + align:start position:0% +to one node and say who's on the network + + + align:start position:0% +to one node and say who's on the network +and you believe them well if I'm that + + align:start position:0% +and you believe them well if I'm that + + + align:start position:0% +and you believe them well if I'm that +note I can say yes I am on the network + + align:start position:0% +note I can say yes I am on the network + + + align:start position:0% +note I can say yes I am on the network +and my friend over here is on the + + align:start position:0% +and my friend over here is on the + + + align:start position:0% +and my friend over here is on the +network and my friend over here is on + + align:start position:0% +network and my friend over here is on + + + align:start position:0% +network and my friend over here is on +the network and no one else is on the + + align:start position:0% +the network and no one else is on the + + + align:start position:0% +the network and no one else is on the +network and I can tell you any number of + + align:start position:0% +network and I can tell you any number of + + + align:start position:0% +network and I can tell you any number of +fake nodes that are all operated by me + + align:start position:0% +fake nodes that are all operated by me + + + align:start position:0% +fake nodes that are all operated by me +and capture all of your traffic that way + + align:start position:0% +and capture all of your traffic that way + + + align:start position:0% +and capture all of your traffic that way +with what's called a route capture + + align:start position:0% +with what's called a route capture + + + align:start position:0% +with what's called a route capture +attack okay so let's maybe we just have + + align:start position:0% +attack okay so let's maybe we just have + + + align:start position:0% +attack okay so let's maybe we just have +a single directory operated by a trusted + + align:start position:0% +a single directory operated by a trusted + + + align:start position:0% +a single directory operated by a trusted +party that's not so good it's a single + + align:start position:0% +party that's not so good it's a single + + + align:start position:0% +party that's not so good it's a single +point of + + align:start position:0% +point of + + + align:start position:0% +point of +failure so you could have well okay + + align:start position:0% +failure so you could have well okay + + + align:start position:0% +failure so you could have well okay +let's have multiple trusted parties and + + align:start position:0% +let's have multiple trusted parties and + + + align:start position:0% +let's have multiple trusted parties and +clients go to these multiple trusted + + align:start position:0% +clients go to these multiple trusted + + + align:start position:0% +clients go to these multiple trusted +parties and get a list of all of the + + align:start position:0% +parties and get a list of all of the + + + align:start position:0% +parties and get a list of all of the +nodes from all of them and combine those + + align:start position:0% +nodes from all of them and combine those + + + align:start position:0% +nodes from all of them and combine those +lists um then you're actually first off + + align:start position:0% +lists um then you're actually first off + + + align:start position:0% +lists um then you're actually first off +you're partitioned in that case if I + + align:start position:0% +you're partitioned in that case if I + + + align:start position:0% +you're partitioned in that case if I +choose these three and you choose those + + align:start position:0% +choose these three and you choose those + + + align:start position:0% +choose these three and you choose those +three and they say anything different + + align:start position:0% +three and they say anything different + + + align:start position:0% +three and they say anything different +then we'll be using different sets of + + align:start position:0% +then we'll be using different sets of + + + align:start position:0% +then we'll be using different sets of +nodes so that's still not good also + + align:start position:0% +nodes so that's still not good also + + + align:start position:0% +nodes so that's still not good also +there's still a attack attempt where + + align:start position:0% +there's still a attack attempt where + + + align:start position:0% +there's still a attack attempt where +like if I say if I use the intersection + + align:start position:0% +like if I say if I use the intersection + + + align:start position:0% +like if I say if I use the intersection +of the sets they tell + + align:start position:0% +of the sets they tell + + + align:start position:0% +of the sets they tell +me then any one of them can keep me from + + align:start position:0% +me then any one of them can keep me from + + + align:start position:0% +me then any one of them can keep me from +using a node they don't like by not + + align:start position:0% +using a node they don't like by not + + + align:start position:0% +using a node they don't like by not +listing it if I use the union anyone can + + align:start position:0% +listing it if I use the union anyone can + + + align:start position:0% +listing it if I use the union anyone can +flood Me by making 20,000 fake servers + + align:start position:0% +flood Me by making 20,000 fake servers + + + align:start position:0% +flood Me by making 20,000 fake servers +that are all them on the list I might do + + align:start position:0% +that are all them on the list I might do + + + align:start position:0% +that are all them on the list I might do +I might compute the result of some sort + + align:start position:0% +I might compute the result of some sort + + + align:start position:0% +I might compute the result of some sort +of vote on them which would solve those + + align:start position:0% +of vote on them which would solve those + + + align:start position:0% +of vote on them which would solve those +two problems but I'd will be partitioned + + align:start position:0% +two problems but I'd will be partitioned + + + align:start position:0% +two problems but I'd will be partitioned +from everyone who's using different + + align:start position:0% +from everyone who's using different + + + align:start position:0% +from everyone who's using different +trusted + + align:start position:0% +trusted + + + align:start position:0% +trusted +parties um we could do a magical + + align:start position:0% +parties um we could do a magical + + + align:start position:0% +parties um we could do a magical +DHT and have we done distributed hash + + align:start position:0% +DHT and have we done distributed hash + + + align:start position:0% +DHT and have we done distributed hash +tables all right we could do some sort + + align:start position:0% +tables all right we could do some sort + + + align:start position:0% +tables all right we could do some sort +of magical distributed structure run by + + align:start position:0% +of magical distributed structure run by + + + align:start position:0% +of magical distributed structure run by +multiple run across all of the nodes I + + align:start position:0% +multiple run across all of the nodes I + + + align:start position:0% +multiple run across all of the nodes I +say magical because although there are + + align:start position:0% +say magical because although there are + + + align:start position:0% +say magical because although there are +designs in this + + align:start position:0% +designs in this + + + align:start position:0% +designs in this +area um there're and some better than + + align:start position:0% +area um there're and some better than + + + align:start position:0% +area um there're and some better than +others none of them really seems to have + + align:start position:0% +others none of them really seems to have + + + align:start position:0% +others none of them really seems to have +a solid security evidence for it at this + + align:start position:0% +a solid security evidence for it at this + + + align:start position:0% +a solid security evidence for it at this +point to the point where I would be + + align:start position:0% +point to the point where I would be + + + align:start position:0% +point to the point where I would be +comfortable and saying yes this is + + align:start position:0% +comfortable and saying yes this is + + + align:start position:0% +comfortable and saying yes this is +actually secure so the solution we wound + + align:start position:0% +actually secure so the solution we wound + + + align:start position:0% +actually secure so the solution we wound +up with is have multiple hardened + + align:start position:0% +up with is have multiple hardened + + + align:start position:0% +up with is have multiple hardened +trusted authorities run by trusted + + align:start position:0% +trusted authorities run by trusted + + + align:start position:0% +trusted authorities run by trusted +parties that collect lists of nodes that + + align:start position:0% +parties that collect lists of nodes that + + + align:start position:0% +parties that collect lists of nodes that +vote on hourly on which nodes are + + align:start position:0% +vote on hourly on which nodes are + + + align:start position:0% +vote on hourly on which nodes are +running that can exclude no that can + + align:start position:0% +running that can exclude no that can + + + align:start position:0% +running that can exclude no that can +vote to exclude nodes that seem to be + + align:start position:0% +vote to exclude nodes that seem to be + + + align:start position:0% +vote to exclude nodes that seem to be +misbehaving that are all running on the + + align:start position:0% +misbehaving that are all running on the + + + align:start position:0% +misbehaving that are all running on the +slash same + + align:start position:0% +slash same + + + align:start position:0% +slash same +sl6 that are doing strange things to + + align:start position:0% +sl6 that are doing strange things to + + + align:start position:0% +sl6 that are doing strange things to +traffic + + align:start position:0% +traffic + + + align:start position:0% +traffic +and have them form a consensus that's + + align:start position:0% +and have them form a consensus that's + + + align:start position:0% +and have them form a consensus that's +the out that's the result of their votes + + align:start position:0% +the out that's the result of their votes + + + align:start position:0% +the out that's the result of their votes +and everybody signs the consensus and + + align:start position:0% +and everybody signs the consensus and + + + align:start position:0% +and everybody signs the consensus and +clients don't use it unless it's signed + + align:start position:0% +clients don't use it unless it's signed + + + align:start position:0% +clients don't use it unless it's signed +by enough authorities this is not the + + align:start position:0% +by enough authorities this is not the + + + align:start position:0% +by enough authorities this is not the +final design but it's the best we've + + align:start position:0% +final design but it's the best we've + + + align:start position:0% +final design but it's the best we've +managed to get come up with so + + align:start position:0% +managed to get come up with so + + + align:start position:0% +managed to get come up with so +far and this way all you need to + + align:start position:0% +far and this way all you need to + + + align:start position:0% +far and this way all you need to +distribute with clients + + align:start position:0% +distribute with clients + + + align:start position:0% +distribute with clients +is um a list of all of the authorities + + align:start position:0% +is um a list of all of the authorities + + + align:start position:0% +is um a list of all of the authorities +public keys and some places to get the + + align:start position:0% +public keys and some places to get the + + + align:start position:0% +public keys and some places to get the +directories you want to have all of the + + align:start position:0% +directories you want to have all of the + + + align:start position:0% +directories you want to have all of the +nodes cach these directories things + + align:start position:0% +nodes cach these directories things + + + align:start position:0% +nodes cach these directories things +because if you don't the bandwidth load + + align:start position:0% +because if you don't the bandwidth load + + + align:start position:0% +because if you don't the bandwidth load +on authorities is + + align:start position:0% + + + + align:start position:0% + +catastrophic so I'm going to skip over + + align:start position:0% +catastrophic so I'm going to skip over + + + align:start position:0% +catastrophic so I'm going to skip over +that because uh um I would love to talk + + align:start position:0% +that because uh um I would love to talk + + + align:start position:0% +that because uh um I would love to talk +about how you choose how clients should + + align:start position:0% +about how you choose how clients should + + + align:start position:0% +about how you choose how clients should +choose which paths to build through the + + align:start position:0% +choose which paths to build through the + + + align:start position:0% +choose which paths to build through the +network I would love to talk about + + align:start position:0% +network I would love to talk about + + + align:start position:0% +network I would love to talk about +issues with applications and making + + align:start position:0% +issues with applications and making + + + align:start position:0% +issues with applications and making +applications not de anonymize themselves + + align:start position:0% +applications not de anonymize themselves + + + align:start position:0% +applications not de anonymize themselves +I'd love to talk about abuse I'd love to + + align:start position:0% +I'd love to talk about abuse I'd love to + + + align:start position:0% +I'd love to talk about abuse I'd love to +talk about hidden services and how they + + align:start position:0% +talk about hidden services and how they + + + align:start position:0% +talk about hidden services and how they +work I'd love to talk about censorship + + align:start position:0% +work I'd love to talk about censorship + + + align:start position:0% +work I'd love to talk about censorship +resistance and + + align:start position:0% +resistance and + + + align:start position:0% +resistance and +I'd like to talk about attacks and + + align:start position:0% +I'd like to talk about attacks and + + + align:start position:0% +I'd like to talk about attacks and +defenses but I've only got 35 minutes + + align:start position:0% +defenses but I've only got 35 minutes + + + align:start position:0% +defenses but I've only got 35 minutes +and I can't possibly cover all of these + + align:start position:0% +and I can't possibly cover all of these + + + align:start position:0% +and I can't possibly cover all of these +so show of hands for how many people + + align:start position:0% +so show of hands for how many people + + + align:start position:0% +so show of hands for how many people +think the most important top I think + + align:start position:0% +think the most important top I think + + + align:start position:0% +think the most important top I think +I've got time if you think about what + + align:start position:0% +I've got time if you think about what + + + align:start position:0% +I've got time if you think about what +you think are the two most important + + align:start position:0% +you think are the two most important + + + align:start position:0% +you think are the two most important +topics on this + + align:start position:0% +topics on this + + + align:start position:0% +topics on this +list if one of your two most important + + align:start position:0% +list if one of your two most important + + + align:start position:0% +list if one of your two most important +topics is path selection and how you + + align:start position:0% +topics is path selection and how you + + + align:start position:0% +topics is path selection and how you +choose nodes please raise your + + align:start position:0% +choose nodes please raise your + + + align:start position:0% +choose nodes please raise your +hand if one of your two most important + + align:start position:0% +hand if one of your two most important + + + align:start position:0% +hand if one of your two most important +topics is application issues and how to + + align:start position:0% +topics is application issues and how to + + + align:start position:0% +topics is application issues and how to +make applications not bust your + + align:start position:0% +make applications not bust your + + + align:start position:0% +make applications not bust your +anonymity please raise your + + align:start position:0% +anonymity please raise your + + + align:start position:0% +anonymity please raise your +hand if one of your most important + + align:start position:0% +hand if one of your most important + + + align:start position:0% +hand if one of your most important +issues is abuse and what kind of abuse + + align:start position:0% +issues is abuse and what kind of abuse + + + align:start position:0% +issues is abuse and what kind of abuse +we see how you can prevent it and how + + align:start position:0% +we see how you can prevent it and how + + + align:start position:0% +we see how you can prevent it and how +that works out please raise your + + align:start position:0% +that works out please raise your + + + align:start position:0% +that works out please raise your +hand okay that one's popular um if one + + align:start position:0% +hand okay that one's popular um if one + + + align:start position:0% +hand okay that one's popular um if one +of your most important topics is how + + align:start position:0% +of your most important topics is how + + + align:start position:0% +of your most important topics is how +hidden Services work and how they can be + + align:start position:0% +hidden Services work and how they can be + + + align:start position:0% +hidden Services work and how they can be +made to work better please raise your + + align:start position:0% +made to work better please raise your + + + align:start position:0% +made to work better please raise your +hand that's wow that's much more popular + + align:start position:0% +hand that's wow that's much more popular + + + align:start position:0% +hand that's wow that's much more popular +on this side of the room than that side + + align:start position:0% +on this side of the room than that side + + + align:start position:0% +on this side of the room than that side +of the room I wonder what's going on are + + align:start position:0% +of the room I wonder what's going on are + + + align:start position:0% +of the room I wonder what's going on are +you guys in a club um are you up to + + align:start position:0% +you guys in a club um are you up to + + + align:start position:0% +you guys in a club um are you up to +something censorship who's interested in + + align:start position:0% +something censorship who's interested in + + + align:start position:0% +something censorship who's interested in +censorship okay that's fairly popular + + align:start position:0% +censorship okay that's fairly popular + + + align:start position:0% +censorship okay that's fairly popular +attacks and + + align:start position:0% +attacks and + + + align:start position:0% +attacks and +defenses it's also okay so we're not + + align:start position:0% +defenses it's also okay so we're not + + + align:start position:0% +defenses it's also okay so we're not +doing paths and we're not doing appu + + align:start position:0% +doing paths and we're not doing appu + + + align:start position:0% +doing paths and we're not doing appu +basically paths um guard nodes guard + + align:start position:0% +basically paths um guard nodes guard + + + align:start position:0% +basically paths um guard nodes guard +nodes seard node designs select by + + align:start position:0% +nodes seard node designs select by + + + align:start position:0% +nodes seard node designs select by +bandwidth you need to actually weight by + + align:start position:0% +bandwidth you need to actually weight by + + + align:start position:0% +bandwidth you need to actually weight by +bandwidth but you also need a trusted + + align:start position:0% +bandwidth but you also need a trusted + + + align:start position:0% +bandwidth but you also need a trusted +way to measure + + align:start position:0% +way to measure + + + align:start position:0% +way to measure +bandwidth and that's the too long didn't + + align:start position:0% +bandwidth and that's the too long didn't + + + align:start position:0% +bandwidth and that's the too long didn't +lecture of what would be on path + + align:start position:0% +lecture of what would be on path + + + align:start position:0% +lecture of what would be on path +selection for + + align:start position:0% +selection for + + + align:start position:0% +selection for +issues almost no protocol is actually + + align:start position:0% +issues almost no protocol is actually + + + align:start position:0% +issues almost no protocol is actually +designed to provide anonymity like with + + align:start position:0% +designed to provide anonymity like with + + + align:start position:0% +designed to provide anonymity like with +the assum because almost every protocol + + align:start position:0% +the assum because almost every protocol + + + align:start position:0% +the assum because almost every protocol +that's widely used has the Assumption in + + align:start position:0% +that's widely used has the Assumption in + + + align:start position:0% +that's widely used has the Assumption in +it well you know anyone who wants to can + + align:start position:0% +it well you know anyone who wants to can + + + align:start position:0% +it well you know anyone who wants to can +just see the IPS on this traffic so + + align:start position:0% +just see the IPS on this traffic so + + + align:start position:0% +just see the IPS on this traffic so +there's no point in trying to conceal + + align:start position:0% +there's no point in trying to conceal + + + align:start position:0% +there's no point in trying to conceal +identity so in a particularly complex + + align:start position:0% +identity so in a particularly complex + + + align:start position:0% +identity so in a particularly complex +protocol like the whole stack of + + align:start position:0% +protocol like the whole stack of + + + align:start position:0% +protocol like the whole stack of +protocols a web browser uses there's no + + align:start position:0% +protocols a web browser uses there's no + + + align:start position:0% +protocols a web browser uses there's no +real way to anonymize that just by + + align:start position:0% +real way to anonymize that just by + + + align:start position:0% +real way to anonymize that just by +anonymizing the traffic with something + + align:start position:0% +anonymizing the traffic with something + + + align:start position:0% +anonymizing the traffic with something +like tor you need to hack the web + + align:start position:0% +like tor you need to hack the web + + + align:start position:0% +like tor you need to hack the web +browser pretty hard to make it stop + + align:start position:0% +browser pretty hard to make it stop + + + align:start position:0% +browser pretty hard to make it stop +doing things like leaking the list of + + align:start position:0% +doing things like leaking the list of + + + align:start position:0% +doing things like leaking the list of +all fonts that are identified on your + + align:start position:0% +all fonts that are identified on your + + + align:start position:0% +all fonts that are identified on your +system leaking your exact window size um + + align:start position:0% +system leaking your exact window size um + + + align:start position:0% +system leaking your exact window size um +allowing all kinds of permanent cookie + + align:start position:0% +allowing all kinds of permanent cookie + + + align:start position:0% +allowing all kinds of permanent cookie +like structures leaking what's in the + + align:start position:0% +like structures leaking what's in the + + + align:start position:0% +like structures leaking what's in the +cache and what's not in the cache and + + align:start position:0% +cache and what's not in the cache and + + + align:start position:0% +cache and what's not in the cache and +and so on so your choices there are + + align:start position:0% +and so on so your choices there are + + + align:start position:0% +and so on so your choices there are +basically isolate everything and restart + + align:start position:0% +basically isolate everything and restart + + + align:start position:0% +basically isolate everything and restart +from a fresh VM all the time or rewrite + + align:start position:0% +from a fresh VM all the time or rewrite + + + align:start position:0% +from a fresh VM all the time or rewrite +the browser or both other things are a + + align:start position:0% +the browser or both other things are a + + + align:start position:0% +the browser or both other things are a +lot easier than web browsers but still + + align:start position:0% +lot easier than web browsers but still + + + align:start position:0% +lot easier than web browsers but still +problematic that's all I'm going to say + + align:start position:0% +problematic that's all I'm going to say + + + align:start position:0% +problematic that's all I'm going to say +about app + + align:start position:0% +about app + + + align:start position:0% +about app +issues let's see I think I got the most + + align:start position:0% +issues let's see I think I got the most + + + align:start position:0% +issues let's see I think I got the most +hands did you see what I got the most + + align:start position:0% +hands did you see what I got the most + + + align:start position:0% +hands did you see what I got the most +hands for any opinions abuse and hidden + + align:start position:0% +hands for any opinions abuse and hidden + + + align:start position:0% +hands for any opinions abuse and hidden +Services abuse and hidden Services all + + align:start position:0% +Services abuse and hidden Services all + + + align:start position:0% +Services abuse and hidden Services all +right um I'll talk about abuse hidden + + align:start position:0% +right um I'll talk about abuse hidden + + + align:start position:0% +right um I'll talk about abuse hidden +services and if I've still got time I'll + + align:start position:0% +services and if I've still got time I'll + + + align:start position:0% +services and if I've still got time I'll +do censorship and attacks um so let's go + + align:start position:0% +do censorship and attacks um so let's go + + + align:start position:0% +do censorship and attacks um so let's go +to + + align:start position:0% +to + + + align:start position:0% +to +abuse abuse abuse + + align:start position:0% +abuse abuse abuse + + + align:start position:0% +abuse abuse abuse +abuse um so one problem that + + align:start position:0% +abuse um so one problem that + + + align:start position:0% +abuse um so one problem that +we've fortunately not had all that much + + align:start position:0% +we've fortunately not had all that much + + + align:start position:0% +we've fortunately not had all that much +of so when we were working on this stuff + + align:start position:0% +of so when we were working on this stuff + + + align:start position:0% +of so when we were working on this stuff +the problem that everybody was afraid of + + align:start position:0% +the problem that everybody was afraid of + + + align:start position:0% +the problem that everybody was afraid of +was this horrible stuff that would get + + align:start position:0% +was this horrible stuff that would get + + + align:start position:0% +was this horrible stuff that would get +you kicked off of any ISP and that would + + align:start position:0% +you kicked off of any ISP and that would + + + align:start position:0% +you kicked off of any ISP and that would +create tremendous legal issues in ruing + + align:start position:0% +create tremendous legal issues in ruing + + + align:start position:0% +create tremendous legal issues in ruing +your lives I speak of course of file + + align:start position:0% +your lives I speak of course of file + + + align:start position:0% +your lives I speak of course of file +sharing um we were terrified that people + + align:start position:0% +sharing um we were terrified that people + + + align:start position:0% +sharing um we were terrified that people +would try to bit torrent or Nutella or + + align:start position:0% +would try to bit torrent or Nutella or + + + align:start position:0% +would try to bit torrent or Nutella or +whatever over this thing yes it was a + + align:start position:0% +whatever over this thing yes it was a + + + align:start position:0% +whatever over this thing yes it was a +long time ago and you know we thought + + align:start position:0% +long time ago and you know we thought + + + align:start position:0% +long time ago and you know we thought +about how we can do that well you'll see + + align:start position:0% +about how we can do that well you'll see + + + align:start position:0% +about how we can do that well you'll see +in the paper that we talk a lot about + + align:start position:0% +in the paper that we talk a lot about + + + align:start position:0% +in the paper that we talk a lot about +exit policies about letting exit nodes + + align:start position:0% +exit policies about letting exit nodes + + + align:start position:0% +exit policies about letting exit nodes +say I only allow connections to Port 80 + + align:start position:0% +say I only allow connections to Port 80 + + + align:start position:0% +say I only allow connections to Port 80 +and Port + + align:start position:0% +and Port + + + align:start position:0% +and Port +443 um this doesn't actually help with + + align:start position:0% +443 um this doesn't actually help with + + + align:start position:0% +443 um this doesn't actually help with +abuse at all because + + align:start position:0% +abuse at all because + + + align:start position:0% +abuse at all because +anything because you can + + align:start position:0% +anything because you can + + + align:start position:0% +anything because you can +um you can try to spread um worms over + + align:start position:0% +um you can try to spread um worms over + + + align:start position:0% +um you can try to spread um worms over +Port 80 you + + align:start position:0% +Port 80 you + + + align:start position:0% +Port 80 you +can um post abusive stuff to IRC + + align:start position:0% +can um post abusive stuff to IRC + + + align:start position:0% +can um post abusive stuff to IRC +channels over web to IRC interfaces + + align:start position:0% +channels over web to IRC interfaces + + + align:start position:0% +channels over web to IRC interfaces +everything's got a web interface these + + align:start position:0% +everything's got a web interface these + + + align:start position:0% +everything's got a web interface these +days so you can't really say it's only + + align:start position:0% +days so you can't really say it's only + + + align:start position:0% +days so you can't really say it's only +web it's safe if it's useful it can be + + align:start position:0% +web it's safe if it's useful it can be + + + align:start position:0% +web it's safe if it's useful it can be +abused that said there are people who + + align:start position:0% +abused that said there are people who + + + align:start position:0% +abused that said there are people who +are willing to run exits that deliver 80 + + align:start position:0% +are willing to run exits that deliver 80 + + + align:start position:0% +are willing to run exits that deliver 80 +and 443 who would not be willing to run + + align:start position:0% +and 443 who would not be willing to run + + + align:start position:0% +and 443 who would not be willing to run +exits delivering all ports so that did + + align:start position:0% +exits delivering all ports so that did + + + align:start position:0% +exits delivering all ports so that did +turn out to be useful just didn't turn + + align:start position:0% +turn out to be useful just didn't turn + + + align:start position:0% +turn out to be useful just didn't turn +out to be a + + align:start position:0% +out to be a + + + align:start position:0% +out to be a +solution + + align:start position:0% +solution + + + align:start position:0% +solution +um another thing that creates problems + + align:start position:0% +um another thing that creates problems + + + align:start position:0% +um another thing that creates problems +it is um let's see criminal activity + + align:start position:0% +it is um let's see criminal activity + + + align:start position:0% +it is um let's see criminal activity +generally doesn't create problems for + + align:start position:0% +generally doesn't create problems for + + + align:start position:0% +generally doesn't create problems for +the network operators so much from time + + align:start position:0% +the network operators so much from time + + + align:start position:0% +the network operators so much from time +to time somebody's server gets seized + + align:start position:0% +to time somebody's server gets seized + + + align:start position:0% +to time somebody's server gets seized +and returns 6 months later and they have + + align:start position:0% +and returns 6 months later and they have + + + align:start position:0% +and returns 6 months later and they have +to wipe the thing that's still an + + align:start position:0% +to wipe the thing that's still an + + + align:start position:0% +to wipe the thing that's still an +infrequent enough occurrence that um + + align:start position:0% +infrequent enough occurrence that um + + + align:start position:0% +infrequent enough occurrence that um +it's somewhat surprising when it + + align:start position:0% +it's somewhat surprising when it + + + align:start position:0% +it's somewhat surprising when it +happens and so yeah don't don't run an + + align:start position:0% +happens and so yeah don't don't run an + + + align:start position:0% +happens and so yeah don't don't run an +exit node on a server that you need to + + align:start position:0% +exit node on a server that you need to + + + align:start position:0% +exit node on a server that you need to +graduate + + align:start position:0% +graduate + + + align:start position:0% +graduate +um what else + + align:start position:0% + + + + align:start position:0% + +uh the biggest problem that we have for + + align:start position:0% +uh the biggest problem that we have for + + + align:start position:0% +uh the biggest problem that we have for +abusive stuff is that many websites + + align:start position:0% +abusive stuff is that many websites + + + align:start position:0% +abusive stuff is that many websites +around the world and many IRC servers + + align:start position:0% +around the world and many IRC servers + + + align:start position:0% +around the world and many IRC servers +and so on use IP based blocking in order + + align:start position:0% +and so on use IP based blocking in order + + + align:start position:0% +and so on use IP based blocking in order +to deter and mitigate abusive Behavior + + align:start position:0% +to deter and mitigate abusive Behavior + + + align:start position:0% +to deter and mitigate abusive Behavior +people people + + align:start position:0% +people people + + + align:start position:0% +people people +posting + + align:start position:0% +posting + + + align:start position:0% +posting +um people picture posting roadkill + + align:start position:0% +um people picture posting roadkill + + + align:start position:0% +um people picture posting roadkill +pictures on My Little Pony sites + + align:start position:0% +pictures on My Little Pony sites + + + align:start position:0% +pictures on My Little Pony sites +people flaming everybody on IRC + + align:start position:0% +people flaming everybody on IRC + + + align:start position:0% +people flaming everybody on IRC +channels people making a lot of leave + + align:start position:0% +channels people making a lot of leave + + + align:start position:0% +channels people making a lot of leave +join + + align:start position:0% +join + + + align:start position:0% +join +requests so um people replacing entire + + align:start position:0% +requests so um people replacing entire + + + align:start position:0% +requests so um people replacing entire +Wikipedia pages with um racial slurs + + align:start position:0% +Wikipedia pages with um racial slurs + + + align:start position:0% +Wikipedia pages with um racial slurs +this stuff is real it is problematic + + align:start position:0% +this stuff is real it is problematic + + + align:start position:0% +this stuff is real it is problematic +it's unacceptable to the websites and + + align:start position:0% +it's unacceptable to the websites and + + + align:start position:0% +it's unacceptable to the websites and +services that use IP based blocking um + + align:start position:0% +services that use IP based blocking um + + + align:start position:0% +services that use IP based blocking um +they need a way to keep this from + + align:start position:0% +they need a way to keep this from + + + align:start position:0% +they need a way to keep this from +happening and IP based blocking is a + + align:start position:0% +happening and IP based blocking is a + + + align:start position:0% +happening and IP based blocking is a +cheap way for them to do that so it's + + align:start position:0% +cheap way for them to do that so it's + + + align:start position:0% +cheap way for them to do that so it's +pretty frequent that Tor gets banned + + align:start position:0% +pretty frequent that Tor gets banned + + + align:start position:0% +pretty frequent that Tor gets banned +completely the T users get banned + + align:start position:0% +completely the T users get banned + + + align:start position:0% +completely the T users get banned +completely from some + + align:start position:0% +completely from some + + + align:start position:0% +completely from some +sites this is there's some work on + + align:start position:0% +sites this is there's some work on + + + align:start position:0% +sites this is there's some work on +trying to say + + align:start position:0% +trying to say + + + align:start position:0% +trying to say +well what's why does IP based blocking + + align:start position:0% +well what's why does IP based blocking + + + align:start position:0% +well what's why does IP based blocking +really work is it because IP based block + + align:start position:0% +really work is it because IP based block + + + align:start position:0% +really work is it because IP based block +is it because IPS are people no + + align:start position:0% +is it because IPS are people no + + + align:start position:0% +is it because IPS are people no +everybody in this room knows how to get + + align:start position:0% +everybody in this room knows how to get + + + align:start position:0% +everybody in this room knows how to get +a different IP if they need one + + align:start position:0% +a different IP if they need one + + + align:start position:0% +a different IP if they need one +everybody in this room knows how to get + + align:start position:0% +everybody in this room knows how to get + + + align:start position:0% +everybody in this room knows how to get +like um tens of thousands of different + + align:start position:0% +like um tens of thousands of different + + + align:start position:0% +like um tens of thousands of different +IPS if they need one if they need tens + + align:start position:0% +IPS if they need one if they need tens + + + align:start position:0% +IPS if they need one if they need tens +of thousands but for most people getting + + align:start position:0% +of thousands but for most people getting + + + align:start position:0% +of thousands but for most people getting +more + + align:start position:0% +more + + + align:start position:0% +more +IPS is at least a little time consuming + + align:start position:0% +IPS is at least a little time consuming + + + align:start position:0% +IPS is at least a little time consuming +and at least a little challenging to the + + align:start position:0% +and at least a little challenging to the + + + align:start position:0% +and at least a little challenging to the +extent that it imposes a rate limit and + + align:start position:0% +extent that it imposes a rate limit and + + + align:start position:0% +extent that it imposes a rate limit and +a resource cost on abuse if you don't + + align:start position:0% +a resource cost on abuse if you don't + + + align:start position:0% +a resource cost on abuse if you don't +own a botn net and if they've already + + align:start position:0% +own a botn net and if they've already + + + align:start position:0% +own a botn net and if they've already +blocked T and all the other proxy + + align:start position:0% +blocked T and all the other proxy + + + align:start position:0% +blocked T and all the other proxy +services so for that you need to look at + + align:start position:0% +services so for that you need to look at + + + align:start position:0% +services so for that you need to look at +different + + align:start position:0% +different + + + align:start position:0% +different +ways um to provide other resource costs + + align:start position:0% +ways um to provide other resource costs + + + align:start position:0% +ways um to provide other resource costs +you can either say well you use have you + + align:start position:0% +you can either say well you use have you + + + align:start position:0% +you can either say well you use have you +done blind + + align:start position:0% +done blind + + + align:start position:0% +done blind +signatures okay you can construct things + + align:start position:0% +signatures okay you can construct things + + + align:start position:0% +signatures okay you can construct things +so that you need an IP to make an + + align:start position:0% +so that you need an IP to make an + + + align:start position:0% +so that you need an IP to make an +account but what account you make with + + align:start position:0% +account but what account you make with + + + align:start position:0% +account but what account you make with +an IP is not linkable to your IP and + + align:start position:0% +an IP is not linkable to your IP and + + + align:start position:0% +an IP is not linkable to your IP and +then later on if the account gets banned + + align:start position:0% +then later on if the account gets banned + + + align:start position:0% +then later on if the account gets banned +you need to create a new account from a + + align:start position:0% +you need to create a new account from a + + + align:start position:0% +you need to create a new account from a +different IP that's something you can + + align:start position:0% +different IP that's something you can + + + align:start position:0% +different IP that's something you can +build and we're working with people to + + align:start position:0% +build and we're working with people to + + + align:start position:0% +build and we're working with people to +work on it there's also although it + + align:start position:0% +work on it there's also although it + + + align:start position:0% +work on it there's also although it +needs more hacking on the integration + + align:start position:0% +needs more hacking on the integration + + + align:start position:0% +needs more hacking on the integration +side something also needs more hacking + + align:start position:0% +side something also needs more hacking + + + align:start position:0% +side something also needs more hacking +on the integration side is anonymous + + align:start position:0% +on the integration side is anonymous + + + align:start position:0% +on the integration side is anonymous +black listable credentials they're a + + align:start position:0% +black listable credentials they're a + + + align:start position:0% +black listable credentials they're a +little esoteric but the idea is + + align:start position:0% + + + + align:start position:0% + +um that you get something that allows + + align:start position:0% +um that you get something that allows + + + align:start position:0% +um that you get something that allows +you to participate on an IRC server for + + align:start position:0% +you to participate on an IRC server for + + + align:start position:0% +you to participate on an IRC server for +example you can use this as many times + + align:start position:0% +example you can use this as many times + + + align:start position:0% +example you can use this as many times +as you want your using it is not + + align:start position:0% +as you want your using it is not + + + align:start position:0% +as you want your using it is not +linkable until you are banned once you + + align:start position:0% +linkable until you are banned once you + + + align:start position:0% +linkable until you are banned once you +are banned future attempts from the same + + align:start position:0% +are banned future attempts from the same + + + align:start position:0% +are banned future attempts from the same +person with the same credential don't + + align:start position:0% +person with the same credential don't + + + align:start position:0% +person with the same credential don't +work but past activities do not become + + align:start position:0% +work but past activities do not become + + + align:start position:0% +work but past activities do not become +linkable to one + + align:start position:0% +linkable to one + + + align:start position:0% +linkable to one +another these can be built pretty easily + + align:start position:0% +another these can be built pretty easily + + + align:start position:0% +another these can be built pretty easily +they the problem is convincing people + + align:start position:0% +they the problem is convincing people + + + align:start position:0% +they the problem is convincing people +who are more or less satisfied with IP + + align:start position:0% +who are more or less satisfied with IP + + + align:start position:0% +who are more or less satisfied with IP +blocking to actually use them and + + align:start position:0% +blocking to actually use them and + + + align:start position:0% +blocking to actually use them and +actually integrating them with + + align:start position:0% +actually integrating them with + + + align:start position:0% +actually integrating them with +Services uh let's see someone inevitably + + align:start position:0% +Services uh let's see someone inevitably + + + align:start position:0% +Services uh let's see someone inevitably +asks me it's kind of neat um so I I + + align:start position:0% +asks me it's kind of neat um so I I + + + align:start position:0% +asks me it's kind of neat um so I I +started these lectur notes based on my + + align:start position:0% +started these lectur notes based on my + + + align:start position:0% +started these lectur notes based on my +lecture from um + + align:start position:0% +lecture from um + + + align:start position:0% +lecture from um +2013 and there was something about the + + align:start position:0% +2013 and there was something about the + + + align:start position:0% +2013 and there was something about the +inevitable question about Silk Road one + + align:start position:0% +inevitable question about Silk Road one + + + align:start position:0% +inevitable question about Silk Road one +getting busted there's the inevitable + + align:start position:0% +getting busted there's the inevitable + + + align:start position:0% +getting busted there's the inevitable +question about Silk Road 2 getting + + align:start position:0% +question about Silk Road 2 getting + + + align:start position:0% +question about Silk Road 2 getting +busted uh Silk Road 2 was a hidden + + align:start position:0% +busted uh Silk Road 2 was a hidden + + + align:start position:0% +busted uh Silk Road 2 was a hidden +service operating on the tour network uh + + align:start position:0% +service operating on the tour network uh + + + align:start position:0% +service operating on the tour network uh +where people would get together to buy + + align:start position:0% +where people would get together to buy + + + align:start position:0% +where people would get together to buy +and sell illegal things mostly illegal + + align:start position:0% +and sell illegal things mostly illegal + + + align:start position:0% +and sell illegal things mostly illegal +drugs um so as far as we know as far as + + align:start position:0% +drugs um so as far as we know as far as + + + align:start position:0% +drugs um so as far as we know as far as +we can find out the guy got busted + + align:start position:0% +we can find out the guy got busted + + + align:start position:0% +we can find out the guy got busted +through bad UPAC like he made a public + + align:start position:0% +through bad UPAC like he made a public + + + align:start position:0% +through bad UPAC like he made a public +posting with his actual name and then + + align:start position:0% +posting with his actual name and then + + + align:start position:0% +posting with his actual name and then +like went and deleted it and put his his + + align:start position:0% +like went and deleted it and put his his + + + align:start position:0% +like went and deleted it and put his his +pseudonym on it tor can't help people + + align:start position:0% +pseudonym on it tor can't help people + + + align:start position:0% +pseudonym on it tor can't help people +against that kind of stuff on the other + + align:start position:0% +against that kind of stuff on the other + + + align:start position:0% +against that kind of stuff on the other +hand if you've been looking at the NSA + + align:start position:0% +hand if you've been looking at the NSA + + + align:start position:0% +hand if you've been looking at the NSA +leaks you know that law enforcement has + + align:start position:0% +leaks you know that law enforcement has + + + align:start position:0% +leaks you know that law enforcement has +been getting information from + + align:start position:0% +been getting information from + + + align:start position:0% +been getting information from +intelligence and then sanitizing it + + align:start position:0% +intelligence and then sanitizing it + + + align:start position:0% +intelligence and then sanitizing it +through a process called um dual + + align:start position:0% +through a process called um dual + + + align:start position:0% +through a process called um dual +construction where the intelligence + + align:start position:0% +construction where the intelligence + + + align:start position:0% +construction where the intelligence +agency will say to the law enforcement + + align:start position:0% +agency will say to the law enforcement + + + align:start position:0% +agency will say to the law enforcement +agency okay look it's Fred over there he + + align:start position:0% +agency okay look it's Fred over there he + + + align:start position:0% +agency okay look it's Fred over there he +did it but that's not admissible in a + + align:start position:0% +did it but that's not admissible in a + + + align:start position:0% +did it but that's not admissible in a +court and you can never admit that we + + align:start position:0% +court and you can never admit that we + + + align:start position:0% +court and you can never admit that we +told you just find some other way to + + align:start position:0% +told you just find some other way to + + + align:start position:0% +told you just find some other way to +find out that Fred did it but Fred did + + align:start position:0% +find out that Fred did it but Fred did + + + align:start position:0% +find out that Fred did it but Fred did +it um According to some of the Snowden + + align:start position:0% +it um According to some of the Snowden + + + align:start position:0% +it um According to some of the Snowden +leaks and some of the leaks from the + + align:start position:0% +leaks and some of the leaks from the + + + align:start position:0% +leaks and some of the leaks from the +other guy who is still not been caught + + align:start position:0% +other guy who is still not been caught + + + align:start position:0% +other guy who is still not been caught +um + + align:start position:0% +um + + + align:start position:0% +um +that's done sometimes so if you look at + + align:start position:0% +that's done sometimes so if you look at + + + align:start position:0% +that's done sometimes so if you look at +um so okay at this point you use your + + align:start position:0% +um so okay at this point you use your + + + align:start position:0% +um so okay at this point you use your +basic basian reasoning skills and you + + align:start position:0% +basic basian reasoning skills and you + + + align:start position:0% +basic basian reasoning skills and you +say well okay would I see this evidence + + align:start position:0% +say well okay would I see this evidence + + + align:start position:0% +say well okay would I see this evidence +if the guy actually got caught because + + align:start position:0% +if the guy actually got caught because + + + align:start position:0% +if the guy actually got caught because +of bad opsac yes I would I would see + + align:start position:0% +of bad opsac yes I would I would see + + + align:start position:0% +of bad opsac yes I would I would see +plenty of I would see bad obsc I would + + align:start position:0% +plenty of I would see bad obsc I would + + + align:start position:0% +plenty of I would see bad obsc I would +see reports that he got caught because + + align:start position:0% +see reports that he got caught because + + + align:start position:0% +see reports that he got caught because +bad obac but what would I see if it were + + align:start position:0% +bad obac but what would I see if it were + + + align:start position:0% +bad obac but what would I see if it were +a dual construction case I would also + + align:start position:0% +a dual construction case I would also + + + align:start position:0% +a dual construction case I would also +see reports that the guy caught by got + + align:start position:0% +see reports that the guy caught by got + + + align:start position:0% +see reports that the guy caught by got +caught by bad + + align:start position:0% +caught by bad + + + align:start position:0% +caught by bad +OPC because the evidence would be that + + align:start position:0% +OPC because the evidence would be that + + + align:start position:0% +OPC because the evidence would be that +we would be available to us is the same + + align:start position:0% +we would be available to us is the same + + + align:start position:0% +we would be available to us is the same +in either case we can't really conclude + + align:start position:0% +in either case we can't really conclude + + + align:start position:0% +in either case we can't really conclude +much from any public reports of that + + align:start position:0% +much from any public reports of that + + + align:start position:0% +much from any public reports of that +that said it does look like the guy got + + align:start position:0% +that said it does look like the guy got + + + align:start position:0% +that said it does look like the guy got +busted by bad opsac it does look like + + align:start position:0% +busted by bad opsac it does look like + + + align:start position:0% +busted by bad opsac it does look like +the kind of bad opsac that you would be + + align:start position:0% +the kind of bad opsac that you would be + + + align:start position:0% +the kind of bad opsac that you would be +looking for if you were trying to catch + + align:start position:0% +looking for if you were trying to catch + + + align:start position:0% +looking for if you were trying to catch +somebody running something like this + + align:start position:0% +somebody running something like this + + + align:start position:0% +somebody running something like this +nevertheless earlier I suggested that + + align:start position:0% +nevertheless earlier I suggested that + + + align:start position:0% +nevertheless earlier I suggested that +nobody please do not use my software to + + align:start position:0% +nobody please do not use my software to + + + align:start position:0% +nobody please do not use my software to +break any laws um also if your life or + + align:start position:0% +break any laws um also if your life or + + + align:start position:0% +break any laws um also if your life or +freedom is at stake from using uh tour + + align:start position:0% +freedom is at stake from using uh tour + + + align:start position:0% +freedom is at stake from using uh tour +or any security + + align:start position:0% +or any security + + + align:start position:0% +or any security +product think do not use that product in + + align:start position:0% +product think do not use that product in + + + align:start position:0% +product think do not use that product in +isolation think of ways to use it to + + align:start position:0% +isolation think of ways to use it to + + + align:start position:0% +isolation think of ways to use it to +construct a series of + + align:start position:0% +construct a series of + + + align:start position:0% +construct a series of +redundant um defenses for yourself if + + align:start position:0% +redundant um defenses for yourself if + + + align:start position:0% +redundant um defenses for yourself if +your if your life or freedom is at stake + + align:start position:0% +your if your life or freedom is at stake + + + align:start position:0% +your if your life or freedom is at stake +or if having the system broken is is + + align:start position:0% +or if having the system broken is is + + + align:start position:0% +or if having the system broken is is +completely unacceptable to you and I'll + + align:start position:0% +completely unacceptable to you and I'll + + + align:start position:0% +completely unacceptable to you and I'll +say that about T and I'll say that about + + align:start position:0% +say that about T and I'll say that about + + + align:start position:0% +say that about T and I'll say that about +TLS and I'll say that about + + align:start position:0% +TLS and I'll say that about + + + align:start position:0% +TLS and I'll say that about +pgp um software is a work in + + align:start position:0% +pgp um software is a work in + + + align:start position:0% +pgp um software is a work in +progress all right so that's the abuse + + align:start position:0% +progress all right so that's the abuse + + + align:start position:0% +progress all right so that's the abuse +section I've got 25 + + align:start position:0% +section I've got 25 + + + align:start position:0% +section I've got 25 +minutes um hidden + + align:start position:0% + + + + align:start position:0% + +Services where's hidden Services um so + + align:start position:0% +Services where's hidden Services um so + + + align:start position:0% +Services where's hidden Services um so +responder anonymity is a much harder + + align:start position:0% +responder anonymity is a much harder + + + align:start position:0% +responder anonymity is a much harder +problem than initiator anonymity + + align:start position:0% +problem than initiator anonymity + + + align:start position:0% +problem than initiator anonymity +initiator anonymity is what you get when + + align:start position:0% +initiator anonymity is what you get when + + + align:start position:0% +initiator anonymity is what you get when +Ellis wants to buy socks and Ellis wants + + align:start position:0% +Ellis wants to buy socks and Ellis wants + + + align:start position:0% +Ellis wants to buy socks and Ellis wants +to stay Anonymous from the sock vendor + + align:start position:0% +to stay Anonymous from the sock vendor + + + align:start position:0% +to stay Anonymous from the sock vendor +responder anonymity is when Ellis wants + + align:start position:0% +responder anonymity is when Ellis wants + + + align:start position:0% +responder anonymity is when Ellis wants +to publish her poetry online and run a + + align:start position:0% +to publish her poetry online and run a + + + align:start position:0% +to publish her poetry online and run a +web server that has her poetry on it but + + align:start position:0% +web server that has her poetry on it but + + + align:start position:0% +web server that has her poetry on it but +not let anyone know where that web + + align:start position:0% +not let anyone know where that web + + + align:start position:0% +not let anyone know where that web +server is because the Poetry is so + + align:start position:0% +server is because the Poetry is so + + + align:start position:0% +server is because the Poetry is so +embarrassing um and yes there actually + + align:start position:0% +embarrassing um and yes there actually + + + align:start position:0% +embarrassing um and yes there actually +is a hidden service out there of mine + + align:start position:0% +is a hidden service out there of mine + + + align:start position:0% +is a hidden service out there of mine +with bad poetry on it no I don't think + + align:start position:0% +with bad poetry on it no I don't think + + + align:start position:0% +with bad poetry on it no I don't think +anybody's actually published it yet no + + align:start position:0% +anybody's actually published it yet no + + + align:start position:0% +anybody's actually published it yet no +I'm not going to tell anybody where it + + align:start position:0% +I'm not going to tell anybody where it + + + align:start position:0% +I'm not going to tell anybody where it +is I'm waiting for it to go + + align:start position:0% +is I'm waiting for it to go + + + align:start position:0% +is I'm waiting for it to go +public uh let's see + + align:start position:0% +public uh let's see + + + align:start position:0% +public uh let's see +so all right one thing you could do + + align:start position:0% +so all right one thing you could do + + + align:start position:0% +so all right one thing you could do +is + + align:start position:0% +is + + + align:start position:0% +is +um so let's see how much time okay I can + + align:start position:0% +um so let's see how much time okay I can + + + align:start position:0% +um so let's see how much time okay I can +do this + + align:start position:0% +do this + + + align:start position:0% +do this +um so um now Ellis wants to publish her + + align:start position:0% +um so um now Ellis wants to publish her + + + align:start position:0% +um so um now Ellis wants to publish her +poetry so I'm going to put Ellis on this + + align:start position:0% +poetry so I'm going to put Ellis on this + + + align:start position:0% +poetry so I'm going to put Ellis on this +end because she's the responder Ellis + + align:start position:0% +end because she's the responder Ellis + + + align:start position:0% +end because she's the responder Ellis +could build a path this represents a lot + + align:start position:0% +could build a path this represents a lot + + + align:start position:0% +could build a path this represents a lot +of relays through the tour Network and + + align:start position:0% +of relays through the tour Network and + + + align:start position:0% +of relays through the tour Network and +then + + align:start position:0% +then + + + align:start position:0% +then +just say say to this Relay please accept + + align:start position:0% +just say say to this Relay please accept + + + align:start position:0% +just say say to this Relay please accept +connections you so now anyone who goes + + align:start position:0% +connections you so now anyone who goes + + + align:start position:0% +connections you so now anyone who goes +to this relay could say hey I want to + + align:start position:0% +to this relay could say hey I want to + + + align:start position:0% +to this relay could say hey I want to +talk to Alice and there have been + + align:start position:0% +talk to Alice and there have been + + + align:start position:0% +talk to Alice and there have been +designs that worked this way it has some + + align:start position:0% +designs that worked this way it has some + + + align:start position:0% +designs that worked this way it has some +challenges though One Challenge is this + + align:start position:0% +challenges though One Challenge is this + + + align:start position:0% +challenges though One Challenge is this +relay could man in the middle all the + + align:start position:0% +relay could man in the middle all the + + + align:start position:0% +relay could man in the middle all the +traffic unless there's a well-known TLS + + align:start position:0% +traffic unless there's a well-known TLS + + + align:start position:0% +traffic unless there's a well-known TLS +key another thing is maybe this relay is + + align:start position:0% +key another thing is maybe this relay is + + + align:start position:0% +key another thing is maybe this relay is +even is also embarrassed by The Poetry + + align:start position:0% +even is also embarrassed by The Poetry + + + align:start position:0% +even is also embarrassed by The Poetry +and does not want to be a public contact + + align:start position:0% +and does not want to be a public contact + + + align:start position:0% +and does not want to be a public contact +point + + align:start position:0% +point + + + align:start position:0% +point +for um poetry so + + align:start position:0% +for um poetry so + + + align:start position:0% +for um poetry so +terrible so um this relay could also be + + align:start position:0% +terrible so um this relay could also be + + + align:start position:0% +terrible so um this relay could also be +pressured by other people who hate the + + align:start position:0% +pressured by other people who hate the + + + align:start position:0% +pressured by other people who hate the +Poetry to censor it this relay could + + align:start position:0% +Poetry to censor it this relay could + + + align:start position:0% +Poetry to censor it this relay could +also be makes itself an attack Target so + + align:start position:0% +also be makes itself an attack Target so + + + align:start position:0% +also be makes itself an attack Target so +you want some way where Alice can go to + + align:start position:0% +you want some way where Alice can go to + + + align:start position:0% +you want some way where Alice can go to +different relays over time and no single + + align:start position:0% +different relays over time and no single + + + align:start position:0% +different relays over time and no single +and no single relay is touching un + + align:start position:0% +and no single relay is touching un + + + align:start position:0% +and no single relay is touching un +encrypted traffic of + + align:start position:0% +encrypted traffic of + + + align:start position:0% +encrypted traffic of +alyses all right well that's doable um + + align:start position:0% +alyses all right well that's doable um + + + align:start position:0% +alyses all right well that's doable um +and + + align:start position:0% +and + + + align:start position:0% +and +but once you have a lot of different + + align:start position:0% +but once you have a lot of different + + + align:start position:0% +but once you have a lot of different +relays what does Alice actually tell + + align:start position:0% +relays what does Alice actually tell + + + align:start position:0% +relays what does Alice actually tell +people it's kind of got to be a public + + align:start position:0% +people it's kind of got to be a public + + + align:start position:0% +people it's kind of got to be a public +key because if she just says relay X + + align:start position:0% +key because if she just says relay X + + + align:start position:0% +key because if she just says relay X +relay y relay Z but x y and z are + + align:start position:0% +relay y relay Z but x y and z are + + + align:start position:0% +relay y relay Z but x y and z are +changing every five minutes that's kind + + align:start position:0% +changing every five minutes that's kind + + + align:start position:0% +changing every five minutes that's kind +of challenging to know you actually got + + align:start position:0% +of challenging to know you actually got + + + align:start position:0% +of challenging to know you actually got +the right relay so let's say she tells + + align:start position:0% +the right relay so let's say she tells + + + align:start position:0% +the right relay so let's say she tells +everybody a public key and when she gets + + align:start position:0% +everybody a public key and when she gets + + + align:start position:0% +everybody a public key and when she gets +over here she says um hey this is Alice + + align:start position:0% +over here she says um hey this is Alice + + + align:start position:0% +over here she says um hey this is Alice +I'll prove it with my public key so now + + align:start position:0% +I'll prove it with my public key so now + + + align:start position:0% +I'll prove it with my public key so now +this relay knows that um + + align:start position:0% +this relay knows that um + + + align:start position:0% +this relay knows that um +public + + align:start position:0% +public + + + align:start position:0% +public +key uh Z + + align:start position:0% +key uh Z + + + align:start position:0% +key uh Z +is um is running a hidden service here + + align:start position:0% +is um is running a hidden service here + + + align:start position:0% +is um is running a hidden service here +and so if anyone else says Hey connect + + align:start position:0% +and so if anyone else says Hey connect + + + align:start position:0% +and so if anyone else says Hey connect +me to public keyz they can do a + + align:start position:0% +me to public keyz they can do a + + + align:start position:0% +me to public keyz they can do a +handshake and wind up with a shared key + + align:start position:0% +handshake and wind up with a shared key + + + align:start position:0% +handshake and wind up with a shared key +with Ellis and it's the same handshake + + align:start position:0% +with Ellis and it's the same handshake + + + align:start position:0% +with Ellis and it's the same handshake +as the tour circuit extension uses and + + align:start position:0% +as the tour circuit extension uses and + + + align:start position:0% +as the tour circuit extension uses and +now Bob can read Ellis's poetry by + + align:start position:0% +now Bob can read Ellis's poetry by + + + align:start position:0% +now Bob can read Ellis's poetry by +building another path through the tour + + align:start position:0% +building another path through the tour + + + align:start position:0% +building another path through the tour +network over here Bob has to know pkz + + align:start position:0% +network over here Bob has to know pkz + + + align:start position:0% +network over here Bob has to know pkz +and Bob can say hey connect me with PK + + align:start position:0% +and Bob can say hey connect me with PK + + + align:start position:0% +and Bob can say hey connect me with PK +send this thing that's sort of like a + + align:start position:0% +send this thing that's sort of like a + + + align:start position:0% +send this thing that's sort of like a +create cell really it's an introduced + + align:start position:0% +create cell really it's an introduced + + + align:start position:0% +create cell really it's an introduced +cell but let's forget that over to Alice + + align:start position:0% +cell but let's forget that over to Alice + + + align:start position:0% +cell but let's forget that over to Alice +they do the same handshake that you that + + align:start position:0% +they do the same handshake that you that + + + align:start position:0% +they do the same handshake that you that +relays do and now they have a shared key + + align:start position:0% +relays do and now they have a shared key + + + align:start position:0% +relays do and now they have a shared key +that they can use for end to end + + align:start position:0% +that they can use for end to end + + + align:start position:0% +that they can use for end to end +encryption well there's something I left + + align:start position:0% +encryption well there's something I left + + + align:start position:0% +encryption well there's something I left +out though which is how does Bob know + + align:start position:0% +out though which is how does Bob know + + + align:start position:0% +out though which is how does Bob know +how to go here and can we do anything + + align:start position:0% +how to go here and can we do anything + + + align:start position:0% +how to go here and can we do anything +about the fact that this relay has to + + align:start position:0% +about the fact that this relay has to + + + align:start position:0% +about the fact that this relay has to +know this public um learns this public + + align:start position:0% +know this public um learns this public + + + align:start position:0% +know this public um learns this public +Key Well we can we can add a direct some + + align:start position:0% +Key Well we can we can add a direct some + + + align:start position:0% +Key Well we can we can add a direct some +kind of directory system where Alis + + align:start position:0% +kind of directory system where Alis + + + align:start position:0% +kind of directory system where Alis +uploads a sign statement anonymously + + align:start position:0% +uploads a sign statement anonymously + + + align:start position:0% +uploads a sign statement anonymously +over T saying pkz is + + align:start position:0% +over T saying pkz is + + + align:start position:0% +over T saying pkz is +at uh relay + + align:start position:0% + + + + align:start position:0% + +X and then Bob says hey give me a sign + + align:start position:0% +X and then Bob says hey give me a sign + + + align:start position:0% +X and then Bob says hey give me a sign +statement to asks the directory system + + align:start position:0% +statement to asks the directory system + + + align:start position:0% +statement to asks the directory system +hey give me a signed statement about + + align:start position:0% +hey give me a signed statement about + + + align:start position:0% +hey give me a signed statement about +pkz and Bob finds out where to go and we + + align:start position:0% +pkz and Bob finds out where to go and we + + + align:start position:0% +pkz and Bob finds out where to go and we +can even do one better and have Alis + + align:start position:0% +can even do one better and have Alis + + + align:start position:0% +can even do one better and have Alis +give a different public key here so this + + align:start position:0% +give a different public key here so this + + + align:start position:0% +give a different public key here so this +can be + + align:start position:0% + + + + align:start position:0% + +pkw and the statement she uploads to the + + align:start position:0% +pkw and the statement she uploads to the + + + align:start position:0% +pkw and the statement she uploads to the +directory can say if you want to talk to + + align:start position:0% +directory can say if you want to talk to + + + align:start position:0% +directory can say if you want to talk to +the service with public keyz then go to + + align:start position:0% +the service with public keyz then go to + + + align:start position:0% +the service with public keyz then go to +relay X and use public key W and now um + + align:start position:0% +relay X and use public key W and now um + + + align:start position:0% +relay X and use public key W and now um +public keyz isn't published here you + + align:start position:0% +public keyz isn't published here you + + + align:start position:0% +public keyz isn't published here you +could even go one farther and encrypt + + align:start position:0% +could even go one farther and encrypt + + + align:start position:0% +could even go one farther and encrypt +this + + align:start position:0% +this + + + align:start position:0% +this +with some shared secret known to Alis + + align:start position:0% +with some shared secret known to Alis + + + align:start position:0% +with some shared secret known to Alis +and Bob and if you do that then the + + align:start position:0% +and Bob and if you do that then the + + + align:start position:0% +and Bob and if you do that then the +directory service and people who can + + align:start position:0% +directory service and people who can + + + align:start position:0% +directory service and people who can +contact the directory service can't + + align:start position:0% +contact the directory service can't + + + align:start position:0% +contact the directory service can't +learn how to connect to Alice with + + align:start position:0% +learn how to connect to Alice with + + + align:start position:0% +learn how to connect to Alice with +that that's yo just a quick question + + align:start position:0% +that that's yo just a quick question + + + align:start position:0% +that that's yo just a quick question +there um if that's not encrypted then RX + + align:start position:0% +there um if that's not encrypted then RX + + + align:start position:0% +there um if that's not encrypted then RX +can still find out that it's running a + + align:start position:0% +can still find out that it's running a + + + align:start position:0% +can still find out that it's running a +service for Alis right yeah well not for + + align:start position:0% +service for Alis right yeah well not for + + + align:start position:0% +service for Alis right yeah well not for +ell it can find out that it's running + + align:start position:0% +ell it can find out that it's running + + + align:start position:0% +ell it can find out that it's running +pkz if this is not encrypted we have a + + align:start position:0% +pkz if this is not encrypted we have a + + + align:start position:0% +pkz if this is not encrypted we have a +design for that um that I'm actually + + align:start position:0% +design for that um that I'm actually + + + align:start position:0% +design for that um that I'm actually +going to get to at the end of this but + + align:start position:0% +going to get to at the end of this but + + + align:start position:0% +going to get to at the end of this but +it's not built yet but it's pretty cool + + align:start position:0% +it's not built yet but it's pretty cool + + + align:start position:0% +it's not built yet but it's pretty cool +um so okay and for you don't want to use + + align:start position:0% +um so okay and for you don't want to use + + + align:start position:0% +um so okay and for you don't want to use +a centralized directory for this so we + + align:start position:0% +a centralized directory for this so we + + + align:start position:0% +a centralized directory for this so we +actually do use a DHT W which is you + + align:start position:0% +actually do use a DHT W which is you + + + align:start position:0% +actually do use a DHT W which is you +know again not perfect and has some + + align:start position:0% +know again not perfect and has some + + + align:start position:0% +know again not perfect and has some +censorship opportunities but we are + + align:start position:0% +censorship opportunities but we are + + + align:start position:0% +censorship opportunities but we are +trying to make those less and less and I + + align:start position:0% +trying to make those less and less and I + + + align:start position:0% +trying to make those less and less and I +want to cover more stuff so I can't do + + align:start position:0% +want to cover more stuff so I can't do + + + align:start position:0% +want to cover more stuff so I can't do +the whole details + + align:start position:0% +the whole details + + + align:start position:0% +the whole details +uh so one of the problems there though + + align:start position:0% +uh so one of the problems there though + + + align:start position:0% +uh so one of the problems there though +is if you you are running one of these + + align:start position:0% +is if you you are running one of these + + + align:start position:0% +is if you you are running one of these +directory Services you get a complete + + align:start position:0% +directory Services you get a complete + + + align:start position:0% +directory Services you get a complete +list of these Keys + + align:start position:0% +list of these Keys + + + align:start position:0% +list of these Keys +pretty uh you know over over time just + + align:start position:0% +pretty uh you know over over time just + + + align:start position:0% +pretty uh you know over over time just +you you run a directory service onod and + + align:start position:0% +you you run a directory service onod and + + + align:start position:0% +you you run a directory service onod and +you get a complete list of all these + + align:start position:0% +you get a complete list of all these + + + align:start position:0% +you get a complete list of all these +keys and you can try connecting to all + + align:start position:0% +keys and you can try connecting to all + + + align:start position:0% +keys and you can try connecting to all +of the ones that don't have encrypted + + align:start position:0% +of the ones that don't have encrypted + + + align:start position:0% +of the ones that don't have encrypted +stuff to find out what's there that's + + align:start position:0% +stuff to find out what's there that's + + + align:start position:0% +stuff to find out what's there that's +called an enumeration attack and we + + align:start position:0% +called an enumeration attack and we + + + align:start position:0% +called an enumeration attack and we +didn't list that in our paper because we + + align:start position:0% +didn't list that in our paper because we + + + align:start position:0% +didn't list that in our paper because we +weren't thinking of that we didn't um + + align:start position:0% +weren't thinking of that we didn't um + + + align:start position:0% +weren't thinking of that we didn't um +but it is something we'd like to resist + + align:start position:0% +but it is something we'd like to resist + + + align:start position:0% +but it is something we'd like to resist +so in the design I hope to be to be + + align:start position:0% +so in the design I hope to be to be + + + align:start position:0% +so in the design I hope to be to be +hacking together sometime in 2014 we're + + align:start position:0% +hacking together sometime in 2014 we're + + + align:start position:0% +hacking together sometime in 2014 we're +going to move towards a key blinding + + align:start position:0% +going to move towards a key blinding + + + align:start position:0% +going to move towards a key blinding +approach where um where Alice and Bob + + align:start position:0% +approach where um where Alice and Bob + + + align:start position:0% +approach where um where Alice and Bob +share + + align:start position:0% + + + + align:start position:0% + +pkw + + align:start position:0% +pkw + + + align:start position:0% +pkw +but sure sorry sh + + align:start position:0% + + + + align:start position:0% + +pkz but this statement is not signed + + align:start position:0% +pkz but this statement is not signed + + + align:start position:0% +pkz but this statement is not signed +with pkz this statement is signed with + + align:start position:0% +with pkz this statement is signed with + + + align:start position:0% +with pkz this statement is signed with +pkz prime where pkz Prime is derived + + align:start position:0% +pkz prime where pkz Prime is derived + + + align:start position:0% +pkz prime where pkz Prime is derived +from + + align:start position:0% + + + + align:start position:0% + +pkz and say um the + + align:start position:0% + + + + align:start position:0% + +date s such that if you know pkz and the + + align:start position:0% +date s such that if you know pkz and the + + + align:start position:0% +date s such that if you know pkz and the +date you can derive pkz + + align:start position:0% +date you can derive pkz + + + align:start position:0% +date you can derive pkz +Prime if you if like Alis you know + + align:start position:0% +Prime if you if like Alis you know + + + align:start position:0% +Prime if you if like Alis you know +secret + + align:start position:0% +secret + + + align:start position:0% +secret +KZ you can generate messages that are + + align:start position:0% +KZ you can generate messages that are + + + align:start position:0% +KZ you can generate messages that are +signed by secret K by pkz Prime + + align:start position:0% +signed by secret K by pkz Prime + + + align:start position:0% +signed by secret K by pkz Prime +but if you only see pkz Prime even + + align:start position:0% +but if you only see pkz Prime even + + + align:start position:0% +but if you only see pkz Prime even +knowing the date you cannot rederive pkz + + align:start position:0% +knowing the date you cannot rederive pkz + + + align:start position:0% +knowing the date you cannot rederive pkz +uh we've got a + + align:start position:0% +uh we've got a + + + align:start position:0% +uh we've got a +proof and if you'd like to find out how + + align:start position:0% +proof and if you'd like to find out how + + + align:start position:0% +proof and if you'd like to find out how +this works then like Ping me and I'll + + align:start position:0% +this works then like Ping me and I'll + + + align:start position:0% +this works then like Ping me and I'll +send you the paper it's it's a cool + + align:start position:0% +send you the paper it's it's a cool + + + align:start position:0% +send you the paper it's it's a cool +trick we + + align:start position:0% +trick we + + + align:start position:0% +trick we +didn't we we were not the first ones to + + align:start position:0% +didn't we we were not the first ones to + + + align:start position:0% +didn't we we were not the first ones to +invent this idea but um that is how + + align:start position:0% +invent this idea but um that is how + + + align:start position:0% +invent this idea but um that is how +we're going to solve a numeration attack + + align:start position:0% +we're going to solve a numeration attack + + + align:start position:0% +we're going to solve a numeration attack +sometime in this coming + + align:start position:0% +sometime in this coming + + + align:start position:0% +sometime in this coming +year assuming that I can actually get + + align:start position:0% +year assuming that I can actually get + + + align:start position:0% +year assuming that I can actually get +the time to build it so that's hidden + + align:start position:0% + + + + align:start position:0% + +Services um attacks and + + align:start position:0% +Services um attacks and + + + align:start position:0% +Services um attacks and +defenses so so far um the biggest + + align:start position:0% +defenses so so far um the biggest + + + align:start position:0% +defenses so so far um the biggest +category of attacks we've seen is + + align:start position:0% +category of attacks we've seen is + + + align:start position:0% +category of attacks we've seen is +attacks at the application Level so if + + align:start position:0% +attacks at the application Level so if + + + align:start position:0% +attacks at the application Level so if +you're running an application over tour + + align:start position:0% +you're running an application over tour + + + align:start position:0% +you're running an application over tour +and it's an unencrypt and it's sending + + align:start position:0% +and it's an unencrypt and it's sending + + + align:start position:0% +and it's an unencrypt and it's sending +unencrypted traffic like regular + + align:start position:0% +unencrypted traffic like regular + + + align:start position:0% +unencrypted traffic like regular +HTTP then + + align:start position:0% +HTTP then + + + align:start position:0% +HTTP then +a hostile exit node just like anyone + + align:start position:0% +a hostile exit node just like anyone + + + align:start position:0% +a hostile exit node just like anyone +else who touches hdtb traffic can + + align:start position:0% +else who touches hdtb traffic can + + + align:start position:0% +else who touches hdtb traffic can +observe and modify the traffic um this + + align:start position:0% +observe and modify the traffic um this + + + align:start position:0% +observe and modify the traffic um this +is the number one attack on the whole + + align:start position:0% +is the number one attack on the whole + + + align:start position:0% +is the number one attack on the whole +system the solution is encrypt your + + align:start position:0% +system the solution is encrypt your + + + align:start position:0% +system the solution is encrypt your +traffic fortunately we're kind of in an + + align:start position:0% +traffic fortunately we're kind of in an + + + align:start position:0% +traffic fortunately we're kind of in an +encryption Renaissance over the last few + + align:start position:0% +encryption Renaissance over the last few + + + align:start position:0% +encryption Renaissance over the last few +years and more and more traffic is + + align:start position:0% +years and more and more traffic is + + + align:start position:0% +years and more and more traffic is +getting encrypted with the Nifty um free + + align:start position:0% +getting encrypted with the Nifty um free + + + align:start position:0% +getting encrypted with the Nifty um free +certificate Authority that eff and + + align:start position:0% +certificate Authority that eff and + + + align:start position:0% +certificate Authority that eff and +Mozilla and Cisco and I forget who else + + align:start position:0% +Mozilla and Cisco and I forget who else + + + align:start position:0% +Mozilla and Cisco and I forget who else +announced a day or two ago there will be + + align:start position:0% +announced a day or two ago there will be + + + align:start position:0% +announced a day or two ago there will be +even less excuse for unencrypted traffic + + align:start position:0% +even less excuse for unencrypted traffic + + + align:start position:0% +even less excuse for unencrypted traffic +in 2015 than there was this year so you + + align:start position:0% +in 2015 than there was this year so you + + + align:start position:0% +in 2015 than there was this year so you +know that solves that more interesting + + align:start position:0% +know that solves that more interesting + + + align:start position:0% +know that solves that more interesting +attacks include things like traffic + + align:start position:0% +attacks include things like traffic + + + align:start position:0% +attacks include things like traffic +tagging so we made a mistake in our + + align:start position:0% +tagging so we made a mistake in our + + + align:start position:0% +tagging so we made a mistake in our +early Integrity checking implementation + + align:start position:0% +early Integrity checking implementation + + + align:start position:0% +early Integrity checking implementation +our early Integrity checking + + align:start position:0% +our early Integrity checking + + + align:start position:0% +our early Integrity checking +implementation um did endtoend checking + + align:start position:0% +implementation um did endtoend checking + + + align:start position:0% +implementation um did endtoend checking +between + + align:start position:0% +between + + + align:start position:0% +between +Alice's program and the exit node + + align:start position:0% +Alice's program and the exit node + + + align:start position:0% +Alice's program and the exit node +but it turns out that that's not quite + + align:start position:0% +but it turns out that that's not quite + + + align:start position:0% +but it turns out that that's not quite +enough because if the first relay messes + + align:start position:0% +enough because if the first relay messes + + + align:start position:0% +enough because if the first relay messes +with the traffic in a way that creates a + + align:start position:0% +with the traffic in a way that creates a + + + align:start position:0% +with the traffic in a way that creates a +a pattern that the exit node can detect + + align:start position:0% +a pattern that the exit node can detect + + + align:start position:0% +a pattern that the exit node can detect +then that's an easy way for the first + + align:start position:0% +then that's an easy way for the first + + + align:start position:0% +then that's an easy way for the first +relay and the last relay to learn that + + align:start position:0% +relay and the last relay to learn that + + + align:start position:0% +relay and the last relay to learn that +they are on the same path and identify + + align:start position:0% +they are on the same path and identify + + + align:start position:0% +they are on the same path and identify +Alice of course if the first relay and + + align:start position:0% +Alice of course if the first relay and + + + align:start position:0% +Alice of course if the first relay and +the last relay happen to be on the same + + align:start position:0% +the last relay happen to be on the same + + + align:start position:0% +the last relay happen to be on the same +path happen to be collaborating anyway + + align:start position:0% +path happen to be collaborating anyway + + + align:start position:0% +path happen to be collaborating anyway +then they can all already identify Alis + + align:start position:0% +then they can all already identify Alis + + + align:start position:0% +then they can all already identify Alis +through traffic correlation we believe + + align:start position:0% +through traffic correlation we believe + + + align:start position:0% +through traffic correlation we believe +but perhaps it should not be so easy for + + align:start position:0% +but perhaps it should not be so easy for + + + align:start position:0% +but perhaps it should not be so easy for +them as as that perhaps traffic + + align:start position:0% +them as as that perhaps traffic + + + align:start position:0% +them as as that perhaps traffic +correlation will someday be harder than + + align:start position:0% +correlation will someday be harder than + + + align:start position:0% +correlation will someday be harder than +we think it would be um it would be good + + align:start position:0% +we think it would be um it would be good + + + align:start position:0% +we think it would be um it would be good +to actually solve that attack for real + + align:start position:0% +to actually solve that attack for real + + + align:start position:0% +to actually solve that attack for real +we've got two solutions for that one is + + align:start position:0% +we've got two solutions for that one is + + + align:start position:0% +we've got two solutions for that one is +the expected out result of this attack + + align:start position:0% +the expected out result of this attack + + + align:start position:0% +the expected out result of this attack +is that periodically circuits will fail + + align:start position:0% +is that periodically circuits will fail + + + align:start position:0% +is that periodically circuits will fail +because the attacker on the first hop + + align:start position:0% +because the attacker on the first hop + + + align:start position:0% +because the attacker on the first hop +guessed wrong about controlling the last + + align:start position:0% +guessed wrong about controlling the last + + + align:start position:0% +guessed wrong about controlling the last +hop so um every Tor client checks for + + align:start position:0% +hop so um every Tor client checks for + + + align:start position:0% +hop so um every Tor client checks for +weird failure rates the real long-term + + align:start position:0% +weird failure rates the real long-term + + + align:start position:0% +weird failure rates the real long-term +fix is to make it so that messing with + + align:start position:0% +fix is to make it so that messing with + + + align:start position:0% +fix is to make it so that messing with +the pattern on the first top doesn't + + align:start position:0% +the pattern on the first top doesn't + + + align:start position:0% +the pattern on the first top doesn't +create more than one bit of information + + align:start position:0% +create more than one bit of information + + + align:start position:0% +create more than one bit of information +on the last toop you can't avoid sending + + align:start position:0% +on the last toop you can't avoid sending + + + align:start position:0% +on the last toop you can't avoid sending +one bit of information because the first + + align:start position:0% +one bit of information because the first + + + align:start position:0% +one bit of information because the first +toop can always just shut down the + + align:start position:0% +toop can always just shut down the + + + align:start position:0% +toop can always just shut down the +connection but if you can limit it to + + align:start position:0% +connection but if you can limit it to + + + align:start position:0% +connection but if you can limit it to +one bit okay two bits because then + + align:start position:0% +one bit okay two bits because then + + + align:start position:0% +one bit okay two bits because then +they'll have the choice to corrupt the + + align:start position:0% +they'll have the choice to corrupt the + + + align:start position:0% +they'll have the choice to corrupt the +data or shut down the + + align:start position:0% +data or shut down the + + + align:start position:0% +data or shut down the +connection but oh I hey I had an idea of + + align:start position:0% +connection but oh I hey I had an idea of + + + align:start position:0% +connection but oh I hey I had an idea of +how to make that better I have to think + + align:start position:0% +how to make that better I have to think + + + align:start position:0% +how to make that better I have to think +about that um let's see do is actually + + align:start position:0% +about that um let's see do is actually + + + align:start position:0% +about that um let's see do is actually +pretty important um there was a paper + + align:start position:0% +pretty important um there was a paper + + + align:start position:0% +pretty important um there was a paper +the other year about something that the + + align:start position:0% +the other year about something that the + + + align:start position:0% +the other year about something that the +author's called the sniper attack where + + align:start position:0% +author's called the sniper attack where + + + align:start position:0% +author's called the sniper attack where +you see traffic coming from a Tor node + + align:start position:0% +you see traffic coming from a Tor node + + + align:start position:0% +you see traffic coming from a Tor node +that you don't control you want to kick + + align:start position:0% +that you don't control you want to kick + + + align:start position:0% +that you don't control you want to kick +everybody off that Tor node so you + + align:start position:0% +everybody off that Tor node so you + + + align:start position:0% +everybody off that Tor node so you +connect to it you fill up all of its + + align:start position:0% +connect to it you fill up all of its + + + align:start position:0% +connect to it you fill up all of its +memory buffers and it + + align:start position:0% +memory buffers and it + + + align:start position:0% +memory buffers and it +crashes then you see whether the traffic + + align:start position:0% +crashes then you see whether the traffic + + + align:start position:0% +crashes then you see whether the traffic +in question gets routed to a node you + + align:start position:0% +in question gets routed to a node you + + + align:start position:0% +in question gets routed to a node you +control or not and your repeat is + + align:start position:0% +control or not and your repeat is + + + align:start position:0% +control or not and your repeat is +necessary + + align:start position:0% +necessary + + + align:start position:0% +necessary +um you can + + align:start position:0% +um you can + + + align:start position:0% +um you can +do for that our best options are um + + align:start position:0% +do for that our best options are um + + + align:start position:0% +do for that our best options are um +first off no longer have memory dos I + + align:start position:0% +first off no longer have memory dos I + + + align:start position:0% +first off no longer have memory dos I +think we have all of the good memory + + align:start position:0% +think we have all of the good memory + + + align:start position:0% +think we have all of the good memory +DS's fixed now there are some bad ones + + align:start position:0% +DS's fixed now there are some bad ones + + + align:start position:0% +DS's fixed now there are some bad ones +that still needed to get addressed but + + align:start position:0% +that still needed to get addressed but + + + align:start position:0% +that still needed to get addressed but +they're screamingly + + align:start position:0% +they're screamingly + + + align:start position:0% +they're screamingly +inefficient the other option for + + align:start position:0% +inefficient the other option for + + + align:start position:0% +inefficient the other option for +resolving this kind of thing is you know + + align:start position:0% +resolving this kind of thing is you know + + + align:start position:0% +resolving this kind of thing is you know +make sure relays are high capacity don't + + align:start position:0% +make sure relays are high capacity don't + + + align:start position:0% +make sure relays are high capacity don't +accept low capacity relays on the + + align:start position:0% +accept low capacity relays on the + + + align:start position:0% +accept low capacity relays on the +network we do that too if you're running + + align:start position:0% +network we do that too if you're running + + + align:start position:0% +network we do that too if you're running +something on your if you're trying to + + align:start position:0% +something on your if you're trying to + + + align:start position:0% +something on your if you're trying to +run a relay on your phone the + + align:start position:0% +run a relay on your phone the + + + align:start position:0% +run a relay on your phone the +authorities won't list + + align:start position:0% +authorities won't list + + + align:start position:0% +authorities won't list +it um but and another is to try to pick + + align:start position:0% +it um but and another is to try to pick + + + align:start position:0% +it um but and another is to try to pick +our circuit scheduling algorithms to so + + align:start position:0% +our circuit scheduling algorithms to so + + + align:start position:0% +our circuit scheduling algorithms to so +that it's hard to starve out circuits + + align:start position:0% +that it's hard to starve out circuits + + + align:start position:0% +that it's hard to starve out circuits +that you don't control that's very hard + + align:start position:0% +that you don't control that's very hard + + + align:start position:0% +that you don't control that's very hard +though and it's it's as yet an unsolved + + align:start position:0% +though and it's it's as yet an unsolved + + + align:start position:0% +though and it's it's as yet an unsolved +problem let's see I should I do an + + align:start position:0% +problem let's see I should I do an + + + align:start position:0% +problem let's see I should I do an +interest attack or an important + + align:start position:0% +interest attack or an important + + + align:start position:0% +interest attack or an important +attack interesting interesting okay um + + align:start position:0% +attack interesting interesting okay um + + + align:start position:0% +attack interesting interesting okay um +so show of hands how many people might + + align:start position:0% +so show of hands how many people might + + + align:start position:0% +so show of hands how many people might +like to write a program that uses + + align:start position:0% +like to write a program that uses + + + align:start position:0% +like to write a program that uses +cryptography + + align:start position:0% +cryptography + + + align:start position:0% +cryptography +someday cool here's what you must learn + + align:start position:0% +someday cool here's what you must learn + + + align:start position:0% +someday cool here's what you must learn +never trust your cryptography + + align:start position:0% +never trust your cryptography + + + align:start position:0% +never trust your cryptography +implementation so even when it's correct + + align:start position:0% +implementation so even when it's correct + + + align:start position:0% +implementation so even when it's correct +it's wrong so long ago there I I think + + align:start position:0% +it's wrong so long ago there I I think + + + align:start position:0% +it's wrong so long ago there I I think +this may be one of the + + align:start position:0% +this may be one of the + + + align:start position:0% +this may be one of the +worst um security bugs that we've had um + + align:start position:0% +worst um security bugs that we've had um + + + align:start position:0% +worst um security bugs that we've had um +any relay could in the middle any + + align:start position:0% +any relay could in the middle any + + + align:start position:0% +any relay could in the middle any +circuit + + align:start position:0% +circuit + + + align:start position:0% +circuit +because we assumed that a correct Diffy + + align:start position:0% +because we assumed that a correct Diffy + + + align:start position:0% +because we assumed that a correct Diffy +Helman + + align:start position:0% +Helman + + + align:start position:0% +Helman +implementation would verify that it was + + align:start position:0% +implementation would verify that it was + + + align:start position:0% +implementation would verify that it was +not being past zero as one of the + + align:start position:0% +not being past zero as one of the + + + align:start position:0% +not being past zero as one of the +inputs the authors of our Diffy helmet + + align:start position:0% +inputs the authors of our Diffy helmet + + + align:start position:0% +inputs the authors of our Diffy helmet +implementation assumed that the proper + + align:start position:0% +implementation assumed that the proper + + + align:start position:0% +implementation assumed that the proper +application would never pass zero to a + + align:start position:0% +application would never pass zero to a + + + align:start position:0% +application would never pass zero to a +Diffy helmet imple + + align:start position:0% +Diffy helmet imple + + + align:start position:0% +Diffy helmet imple +implementation um so so so you know Dy + + align:start position:0% +implementation um so so so you know Dy + + + align:start position:0% +implementation um so so so you know Dy +Helman I say G to the X you say G to the + + align:start position:0% +Helman I say G to the X you say G to the + + + align:start position:0% +Helman I say G to the X you say G to the +Y y I know X you know Y and we can comp + + align:start position:0% +Y y I know X you know Y and we can comp + + + align:start position:0% +Y y I know X you know Y and we can comp +both compute GT thex y now you've done + + align:start position:0% +both compute GT thex y now you've done + + + align:start position:0% +both compute GT thex y now you've done +the fman good um well you know if if + + align:start position:0% +the fman good um well you know if if + + + align:start position:0% +the fman good um well you know if if +Instead The Man in the middle replaces + + align:start position:0% +Instead The Man in the middle replaces + + + align:start position:0% +Instead The Man in the middle replaces +my G to the X with zero and your G to + + align:start position:0% +my G to the X with zero and your G to + + + align:start position:0% +my G to the X with zero and your G to +the X with with zero and then I happily + + align:start position:0% +the X with with zero and then I happily + + + align:start position:0% +the X with with zero and then I happily +compute zero to the X and you compute + + align:start position:0% +compute zero to the X and you compute + + + align:start position:0% +compute zero to the X and you compute +zero to the Y we will have the same key + + align:start position:0% +zero to the Y we will have the same key + + + align:start position:0% +zero to the Y we will have the same key +we will happily talk to each other but + + align:start position:0% +we will happily talk to each other but + + + align:start position:0% +we will happily talk to each other but +this will be an a key that the attacker + + align:start position:0% +this will be an a key that the attacker + + + align:start position:0% +this will be an a key that the attacker +knows because it's zero one also + + align:start position:0% +knows because it's zero one also + + + align:start position:0% +knows because it's zero one also +works p also works p+ one also works so + + align:start position:0% +works p also works p+ one also works so + + + align:start position:0% +works p also works p+ one also works so +you you basically just need to make sure + + align:start position:0% +you you basically just need to make sure + + + align:start position:0% +you you basically just need to make sure +that your values here are within range + + align:start position:0% +that your values here are within range + + + align:start position:0% +that your values here are within range +two and P minus one if you're doing uh + + align:start position:0% +two and P minus one if you're doing uh + + + align:start position:0% +two and P minus one if you're doing uh +Diffy Helman in in Zu + + align:start position:0% +Diffy Helman in in Zu + + + align:start position:0% +Diffy Helman in in Zu +subp okay let's see I would love to talk + + align:start position:0% +subp okay let's see I would love to talk + + + align:start position:0% +subp okay let's see I would love to talk +more about censorship because actually + + align:start position:0% +more about censorship because actually + + + align:start position:0% +more about censorship because actually +it's one of the areas where we can do + + align:start position:0% +it's one of the areas where we can do + + + align:start position:0% +it's one of the areas where we can do +the most good + + align:start position:0% +the most good + + + align:start position:0% +the most good +generally the summarized summarized + + align:start position:0% +generally the summarized summarized + + + align:start position:0% +generally the summarized summarized +version of that was in the earliest + + align:start position:0% +version of that was in the earliest + + + align:start position:0% +version of that was in the earliest +paper you read and in some of the + + align:start position:0% +paper you read and in some of the + + + align:start position:0% +paper you read and in some of the +updates we were still on the idea that + + align:start position:0% +updates we were still on the idea that + + + align:start position:0% +updates we were still on the idea that +we would try to make tour look just like + + align:start position:0% +we would try to make tour look just like + + + align:start position:0% +we would try to make tour look just like +a web client talking to a web server + + align:start position:0% +a web client talking to a web server + + + align:start position:0% +a web client talking to a web server +over https and make that hard to block + + align:start position:0% +over https and make that hard to block + + + align:start position:0% +over https and make that hard to block +turns out that's fantastically difficult + + align:start position:0% +turns out that's fantastically difficult + + + align:start position:0% +turns out that's fantastically difficult +and probably not worth doing uh instead + + align:start position:0% +and probably not worth doing uh instead + + + align:start position:0% +and probably not worth doing uh instead +the approach we take now is using + + align:start position:0% +the approach we take now is using + + + align:start position:0% +the approach we take now is using +different plug-in programs that um a + + align:start position:0% +different plug-in programs that um a + + + align:start position:0% +different plug-in programs that um a +non-listed relay called a bridge can use + + align:start position:0% +non-listed relay called a bridge can use + + + align:start position:0% +non-listed relay called a bridge can use +and a client can use to do different + + align:start position:0% +and a client can use to do different + + + align:start position:0% +and a client can use to do different +traffic transformations + + align:start position:0% +traffic transformations + + + align:start position:0% +traffic transformations +and we manag to keep adding new ones of + + align:start position:0% +and we manag to keep adding new ones of + + + align:start position:0% +and we manag to keep adding new ones of +those faster than the sensors have been + + align:start position:0% +those faster than the sensors have been + + + align:start position:0% +those faster than the sensors have been +able to implement blocking for them and + + align:start position:0% +able to implement blocking for them and + + + align:start position:0% +able to implement blocking for them and +that's + + align:start position:0% +that's + + + align:start position:0% +that's +actually a case where um none of the + + align:start position:0% +actually a case where um none of the + + + align:start position:0% +actually a case where um none of the +solutions are actually categorically + + align:start position:0% +solutions are actually categorically + + + align:start position:0% +solutions are actually categorically +workable + + align:start position:0% +workable + + + align:start position:0% +workable +but that's not a well-formed sentence + + align:start position:0% +but that's not a well-formed sentence + + + align:start position:0% +but that's not a well-formed sentence +none of these plugins are inherently + + align:start position:0% +none of these plugins are inherently + + + align:start position:0% +none of these plugins are inherently +unblockable by any Tech imaginable + + align:start position:0% +unblockable by any Tech imaginable + + + align:start position:0% +unblockable by any Tech imaginable +technique so far but they're good enough + + align:start position:0% +technique so far but they're good enough + + + align:start position:0% +technique so far but they're good enough +to keep traffic unblocked for a year or + + align:start position:0% +to keep traffic unblocked for a year or + + + align:start position:0% +to keep traffic unblocked for a year or +two in most places and six or seven + + align:start position:0% +two in most places and six or seven + + + align:start position:0% +two in most places and six or seven +months at a time in + + align:start position:0% +months at a time in + + + align:start position:0% +months at a time in +China China currently has the most + + align:start position:0% +China China currently has the most + + + align:start position:0% +China China currently has the most +competent sensors in the + + align:start position:0% +competent sensors in the + + + align:start position:0% +competent sensors in the +world largely because China doesn't + + align:start position:0% +world largely because China doesn't + + + align:start position:0% +world largely because China doesn't +Outsource most other censoring countries + + align:start position:0% +Outsource most other censoring countries + + + align:start position:0% +Outsource most other censoring countries +Outsource their censorship to dishonest + + align:start position:0% +Outsource their censorship to dishonest + + + align:start position:0% +Outsource their censorship to dishonest +European American and Asian companies + + align:start position:0% +European American and Asian companies + + + align:start position:0% +European American and Asian companies +whose incentives are not actually to + + align:start position:0% +whose incentives are not actually to + + + align:start position:0% +whose incentives are not actually to +sell them good censorship but to keep + + align:start position:0% +sell them good censorship but to keep + + + align:start position:0% +sell them good censorship but to keep +them on an upgrade treadmill so if you + + align:start position:0% +them on an upgrade treadmill so if you + + + align:start position:0% +them on an upgrade treadmill so if you +were buying your censorship software + + align:start position:0% +were buying your censorship software + + + align:start position:0% +were buying your censorship software +from the United States which technically + + align:start position:0% +from the United States which technically + + + align:start position:0% +from the United States which technically +speaking us companies aren't allowed to + + align:start position:0% +speaking us companies aren't allowed to + + + align:start position:0% +speaking us companies aren't allowed to +make censorship software for Nations but + + align:start position:0% +make censorship software for Nations but + + + align:start position:0% +make censorship software for Nations but +they just make you know corporate + + align:start position:0% +they just make you know corporate + + + align:start position:0% +they just make you know corporate +firewall software that happens to scale + + align:start position:0% +firewall software that happens to scale + + + align:start position:0% +firewall software that happens to scale +to 10 million + + align:start position:0% +to 10 million + + + align:start position:0% +to 10 million +people um yeah I think that's unethical + + align:start position:0% +people um yeah I think that's unethical + + + align:start position:0% +people um yeah I think that's unethical +but again I'm not the political + + align:start position:0% +but again I'm not the political + + + align:start position:0% +but again I'm not the political +scientist of the organization or the + + align:start position:0% +scientist of the organization or the + + + align:start position:0% +scientist of the organization or the +philosopher uh Paul cyers one of the + + align:start position:0% +philosopher uh Paul cyers one of the + + + align:start position:0% +philosopher uh Paul cyers one of the +original onion writing authors does have + + align:start position:0% +original onion writing authors does have + + + align:start position:0% +original onion writing authors does have +a degree in Philosophy for what that's + + align:start position:0% +a degree in Philosophy for what that's + + + align:start position:0% +a degree in Philosophy for what that's +worth which means that he can't answer + + align:start position:0% +worth which means that he can't answer + + + align:start position:0% +worth which means that he can't answer +these questions either but he takes a + + align:start position:0% +these questions either but he takes a + + + align:start position:0% +these questions either but he takes a +lot longer not to answer + + align:start position:0% +lot longer not to answer + + + align:start position:0% +lot longer not to answer +them um + + align:start position:0% +them um + + + align:start position:0% +them um +right where was I 90 minutes is a long + + align:start position:0% +right where was I 90 minutes is a long + + + align:start position:0% +right where was I 90 minutes is a long +time um + + align:start position:0% +time um + + + align:start position:0% +time um +censorship right so what what the sensor + + align:start position:0% +censorship right so what what the sensor + + + align:start position:0% +censorship right so what what the sensor +Weare providers do is once Tor gets + + align:start position:0% +Weare providers do is once Tor gets + + + align:start position:0% +Weare providers do is once Tor gets +around their + + align:start position:0% +around their + + + align:start position:0% +around their +censorship they will block the most + + align:start position:0% +censorship they will block the most + + + align:start position:0% +censorship they will block the most +recent version of Tor but they do it in + + align:start position:0% +recent version of Tor but they do it in + + + align:start position:0% +recent version of Tor but they do it in +a way that is the weakest possible block + + align:start position:0% +a way that is the weakest possible block + + + align:start position:0% +a way that is the weakest possible block +so if like we change one bit in one + + align:start position:0% +so if like we change one bit in one + + + align:start position:0% +so if like we change one bit in one +identifier somewhere we get around it we + + align:start position:0% +identifier somewhere we get around it we + + + align:start position:0% +identifier somewhere we get around it we +can't prove that they're doing this on + + align:start position:0% +can't prove that they're doing this on + + + align:start position:0% +can't prove that they're doing this on +purpose to ensure that tour will evade + + align:start position:0% +purpose to ensure that tour will evade + + + align:start position:0% +purpose to ensure that tour will evade +their version so that they can say so + + align:start position:0% +their version so that they can say so + + + align:start position:0% +their version so that they can say so +that they can sell tour blocking and + + align:start position:0% +that they can sell tour blocking and + + + align:start position:0% +that they can sell tour blocking and +then have it not work so they can sell + + align:start position:0% +then have it not work so they can sell + + + align:start position:0% +then have it not work so they can sell +the upgrade and then sell the next + + align:start position:0% +the upgrade and then sell the next + + + align:start position:0% +the upgrade and then sell the next +upgrade and sell the next upgrade but it + + align:start position:0% +upgrade and sell the next upgrade but it + + + align:start position:0% +upgrade and sell the next upgrade but it +sure does seem that way so yeah don't + + align:start position:0% +sure does seem that way so yeah don't + + + align:start position:0% +sure does seem that way so yeah don't +that's another reason not to work for + + align:start position:0% +that's another reason not to work for + + + align:start position:0% +that's another reason not to work for +censorship providers they're + + align:start position:0% +censorship providers they're + + + align:start position:0% +censorship providers they're +tremendously unethical and they don't + + align:start position:0% +tremendously unethical and they don't + + + align:start position:0% +tremendously unethical and they don't +provide very good + + align:start position:0% +provide very good + + + align:start position:0% +provide very good +software um if you interested in writing + + align:start position:0% +software um if you interested in writing + + + align:start position:0% +software um if you interested in writing +any of these pluggable transport things + + align:start position:0% +any of these pluggable transport things + + + align:start position:0% +any of these pluggable transport things +that is an excellent kind of thing to do + + align:start position:0% +that is an excellent kind of thing to do + + + align:start position:0% +that is an excellent kind of thing to do +as a student project + + align:start position:0% +as a student project + + + align:start position:0% +as a student project +loads of fun learn a little bit about + + align:start position:0% +loads of fun learn a little bit about + + + align:start position:0% +loads of fun learn a little bit about +crypto learn a little bit about + + align:start position:0% +crypto learn a little bit about + + + align:start position:0% +crypto learn a little bit about +networking and so long as you do it in a + + align:start position:0% +networking and so long as you do it in a + + + align:start position:0% +networking and so long as you do it in a +memory safe language you can't screw up + + align:start position:0% +memory safe language you can't screw up + + + align:start position:0% +memory safe language you can't screw up +that badly the worst thing that get that + + align:start position:0% +that badly the worst thing that get that + + + align:start position:0% +that badly the worst thing that get that +gets happened is it gets censored after + + align:start position:0% +gets happened is it gets censored after + + + align:start position:0% +gets happened is it gets censored after +a month instead of after a + + align:start position:0% +a month instead of after a + + + align:start position:0% +a month instead of after a +year and that's what I went to oh the + + align:start position:0% +year and that's what I went to oh the + + + align:start position:0% +year and that's what I went to oh the +agenda related to work um Tor is not is + + align:start position:0% +agenda related to work um Tor is not is + + + align:start position:0% +agenda related to work um Tor is not is +the most popular system of its kind but + + align:start position:0% +the most popular system of its kind but + + + align:start position:0% +the most popular system of its kind but +it's not the only one lots of others + + align:start position:0% +it's not the only one lots of others + + + align:start position:0% +it's not the only one lots of others +have really good ideas and you should + + align:start position:0% +have really good ideas and you should + + + align:start position:0% +have really good ideas and you should +check them out too if you're interested + + align:start position:0% +check them out too if you're interested + + + align:start position:0% +check them out too if you're interested +in um learning all of the stuff I'm not + + align:start position:0% +in um learning all of the stuff I'm not + + + align:start position:0% +in um learning all of the stuff I'm not +thinking about enough and all of the + + align:start position:0% +thinking about enough and all of the + + + align:start position:0% +thinking about enough and all of the +reasons I'm wrong uh freeh haven. net + + align:start position:0% +reasons I'm wrong uh freeh haven. net + + + align:start position:0% +reasons I'm wrong uh freeh haven. net +nonb lists the academic research and + + align:start position:0% +nonb lists the academic research and + + + align:start position:0% +nonb lists the academic research and +Publications in this area but not all + + align:start position:0% +Publications in this area but not all + + + align:start position:0% +Publications in this area but not all +the research in this area is academic + + align:start position:0% +the research in this area is academic + + + align:start position:0% +the research in this area is academic +you should also look at + + align:start position:0% +you should also look at + + + align:start position:0% +you should also look at +i2p + + align:start position:0% +i2p + + + align:start position:0% +i2p +gunet + + align:start position:0% +gunet + + + align:start position:0% +gunet +Freedom which is currently defunct no + + align:start position:0% +Freedom which is currently defunct no + + + align:start position:0% +Freedom which is currently defunct no +pun + + align:start position:0% +pun + + + align:start position:0% +pun +intended um + + align:start position:0% + + + + align:start position:0% + +Mixmaster mix + + align:start position:0% + + + + align:start position:0% + +minion uh Sphinx with a Y Sphinx with an + + align:start position:0% +minion uh Sphinx with a Y Sphinx with an + + + align:start position:0% +minion uh Sphinx with a Y Sphinx with an +i is something + + align:start position:0% + + + + align:start position:0% + +different um DC + + align:start position:0% +different um DC + + + align:start position:0% +different um DC +Nets particularly the work of um is it + + align:start position:0% +Nets particularly the work of um is it + + + align:start position:0% +Nets particularly the work of um is it +Brian Ford Brian Ford on U making this + + align:start position:0% +Brian Ford Brian Ford on U making this + + + align:start position:0% +Brian Ford Brian Ford on U making this +and also of the team at Technical + + align:start position:0% +and also of the team at Technical + + + align:start position:0% +and also of the team at Technical +University Dresden in make trying to + + align:start position:0% +University Dresden in make trying to + + + align:start position:0% +University Dresden in make trying to +make DC Nets practical they're very + + align:start position:0% +make DC Nets practical they're very + + + align:start position:0% +make DC Nets practical they're very +strong they're just not actually + + align:start position:0% +strong they're just not actually + + + align:start position:0% +strong they're just not actually +Deployable yet and many + + align:start position:0% +Deployable yet and many + + + align:start position:0% +Deployable yet and many +others these tend to + + align:start position:0% +others these tend to + + + align:start position:0% +others these tend to +get why why these get less use or + + align:start position:0% +get why why these get less use or + + + align:start position:0% +get why why these get less use or +attention than tour is a open topic of + + align:start position:0% +attention than tour is a open topic of + + + align:start position:0% +attention than tour is a open topic of +some interest that I don't have a solid + + align:start position:0% +some interest that I don't have a solid + + + align:start position:0% +some interest that I don't have a solid +answer + + align:start position:0% +answer + + + align:start position:0% +answer +for future work + + align:start position:0% +for future work + + + align:start position:0% +for future work +um so one of the reasons I do these is + + align:start position:0% +um so one of the reasons I do these is + + + align:start position:0% +um so one of the reasons I do these is +not just because I would like everybody + + align:start position:0% +not just because I would like everybody + + + align:start position:0% +not just because I would like everybody +to know about the cool software I work + + align:start position:0% +to know about the cool software I work + + + align:start position:0% +to know about the cool software I work +on but also because I know students have + + align:start position:0% +on but also because I know students have + + + align:start position:0% +on but also because I know students have +lots and lots of free time and I'm kind + + align:start position:0% +lots and lots of free time and I'm kind + + + align:start position:0% +lots and lots of free time and I'm kind +of hoping to recruit okay you may think + + align:start position:0% +of hoping to recruit okay you may think + + + align:start position:0% +of hoping to recruit okay you may think +I'm joking but um when I was just + + align:start position:0% +I'm joking but um when I was just + + + align:start position:0% +I'm joking but um when I was just +getting started in this field I was + + align:start position:0% +getting started in this field I was + + + align:start position:0% +getting started in this field I was +complaining about how I was so busy like + + align:start position:0% +complaining about how I was so busy like + + + align:start position:0% +complaining about how I was so busy like +reviewing papers for one conference + + align:start position:0% +reviewing papers for one conference + + + align:start position:0% +reviewing papers for one conference +writing software fixing a bug answering + + align:start position:0% +writing software fixing a bug answering + + + align:start position:0% +writing software fixing a bug answering +email I was complaining to some senior + + align:start position:0% +email I was complaining to some senior + + + align:start position:0% +email I was complaining to some senior +faculty member and he told + + align:start position:0% +faculty member and he told + + + align:start position:0% +faculty member and he told +me you will never have so much free time + + align:start position:0% +me you will never have so much free time + + + align:start position:0% +me you will never have so much free time +as you do + + align:start position:0% +as you do + + + align:start position:0% +as you do +today this is actually you actually have + + align:start position:0% +today this is actually you actually have + + + align:start position:0% +today this is actually you actually have +a lot more free time now than you will + + align:start position:0% +a lot more free time now than you will + + + align:start position:0% +a lot more free time now than you will +in 10 years so this is the great time to + + align:start position:0% +in 10 years so this is the great time to + + + align:start position:0% +in 10 years so this is the great time to +work on crazy software + + align:start position:0% +work on crazy software + + + align:start position:0% +work on crazy software +projects and so let me tell you about + + align:start position:0% +projects and so let me tell you about + + + align:start position:0% +projects and so let me tell you about +future work in tour there's this uh key + + align:start position:0% +future work in tour there's this uh key + + + align:start position:0% +future work in tour there's this uh key +blinding thing and a complete revamp of + + align:start position:0% +blinding thing and a complete revamp of + + + align:start position:0% +blinding thing and a complete revamp of +our hidden Services system which was you + + align:start position:0% +our hidden Services system which was you + + + align:start position:0% +our hidden Services system which was you +know the best we could design when we + + align:start position:0% +know the best we could design when we + + + align:start position:0% +know the best we could design when we +came up with it but there's been a lot + + align:start position:0% +came up with it but there's been a lot + + + align:start position:0% +came up with it but there's been a lot +of research since then maybe some of it + + align:start position:0% +of research since then maybe some of it + + + align:start position:0% +of research since then maybe some of it +will turn out to be a good idea we're + + align:start position:0% +will turn out to be a good idea we're + + + align:start position:0% +will turn out to be a good idea we're +also revamping most of our crypto we + + align:start position:0% +also revamping most of our crypto we + + + align:start position:0% +also revamping most of our crypto we +chose schemes that seemed like a good + + align:start position:0% +chose schemes that seemed like a good + + + align:start position:0% +chose schemes that seemed like a good +security performance tradeoff in 2003 + + align:start position:0% +security performance tradeoff in 2003 + + + align:start position:0% +security performance tradeoff in 2003 +like RSA 1024 we've replaced the really + + align:start position:0% +like RSA 1024 we've replaced the really + + + align:start position:0% +like RSA 1024 we've replaced the really +important uses of RSA 1024 with stronger + + align:start position:0% +important uses of RSA 1024 with stronger + + + align:start position:0% +important uses of RSA 1024 with stronger +stuff uh currently curve 25519 but + + align:start position:0% +stuff uh currently curve 25519 but + + + align:start position:0% +stuff uh currently curve 25519 but +there's still some cases that we want to + + align:start position:0% +there's still some cases that we want to + + + align:start position:0% +there's still some cases that we want to +replace in the protocol that we need + + align:start position:0% +replace in the protocol that we need + + + align:start position:0% +replace in the protocol that we need +some work on um I didn't talk too much + + align:start position:0% +some work on um I didn't talk too much + + + align:start position:0% +some work on um I didn't talk too much +about path selection so I can't talk too + + align:start position:0% +about path selection so I can't talk too + + + align:start position:0% +about path selection so I can't talk too +much about improvements in path + + align:start position:0% +much about improvements in path + + + align:start position:0% +much about improvements in path +selection but our path selection + + align:start position:0% +selection but our path selection + + + align:start position:0% +selection but our path selection +algorithms were chosen pretty naely and + + align:start position:0% +algorithms were chosen pretty naely and + + + align:start position:0% +algorithms were chosen pretty naely and +there's there's been some awesome + + align:start position:0% +there's there's been some awesome + + + align:start position:0% +there's there's been some awesome +research in the past five or six years + + align:start position:0% +research in the past five or six years + + + align:start position:0% +research in the past five or six years +on that that we need to + + align:start position:0% + + + + align:start position:0% + +integrate there's a little work that's + + align:start position:0% +integrate there's a little work that's + + + align:start position:0% +integrate there's a little work that's +been done on mixing High latency and low + + align:start position:0% +been done on mixing High latency and low + + + align:start position:0% +been done on mixing High latency and low +latency traffic so that the low latency + + align:start position:0% +latency traffic so that the low latency + + + align:start position:0% +latency traffic so that the low latency +traffic can provide cover for the high + + align:start position:0% +traffic can provide cover for the high + + + align:start position:0% +traffic can provide cover for the high +latency traffic in terms of providing + + align:start position:0% +latency traffic in terms of providing + + + align:start position:0% +latency traffic in terms of providing +lots of users while the high latency + + align:start position:0% +lots of users while the high latency + + + align:start position:0% +lots of users while the high latency +traffic is still very well + + align:start position:0% +traffic is still very well + + + align:start position:0% +traffic is still very well +anonymized um it's not clear whether + + align:start position:0% +anonymized um it's not clear whether + + + align:start position:0% +anonymized um it's not clear whether +this would work or not it's not clear + + align:start position:0% +this would work or not it's not clear + + + align:start position:0% +this would work or not it's not clear +whether would use this or + + align:start position:0% +whether would use this or + + + align:start position:0% +whether would use this or +not and it is clear that unless + + align:start position:0% +not and it is clear that unless + + + align:start position:0% +not and it is clear that unless +something changes or unless some major + + align:start position:0% +something changes or unless some major + + + align:start position:0% +something changes or unless some major +fundinger for that in particular shows + + align:start position:0% +fundinger for that in particular shows + + + align:start position:0% +fundinger for that in particular shows +up I'm not going to have time to work on + + align:start position:0% +up I'm not going to have time to work on + + + align:start position:0% +up I'm not going to have time to work on +it in 2015 but if somebody else wants to + + align:start position:0% +it in 2015 but if somebody else wants to + + + align:start position:0% +it in 2015 but if somebody else wants to +hack on it my God that would be fun um + + align:start position:0% +hack on it my God that would be fun um + + + align:start position:0% +hack on it my God that would be fun um +our congestion control algorithms were + + align:start position:0% +our congestion control algorithms were + + + align:start position:0% +our congestion control algorithms were +chosen questionably based on what we + + align:start position:0% +chosen questionably based on what we + + + align:start position:0% +chosen questionably based on what we +could hack together in a week um we've + + align:start position:0% +could hack together in a week um we've + + + align:start position:0% +could hack together in a week um we've +improved them but they could use a + + align:start position:0% +improved them but they could use a + + + align:start position:0% +improved them but they could use a +bigger + + align:start position:0% +bigger + + + align:start position:0% +bigger +revamp there's some research on scaling + + align:start position:0% +revamp there's some research on scaling + + + align:start position:0% +revamp there's some research on scaling +to hundreds of thousands of nodes so in + + align:start position:0% +to hundreds of thousands of nodes so in + + + align:start position:0% +to hundreds of thousands of nodes so in +the current design + + align:start position:0% +the current design + + + align:start position:0% +the current design +we can probably get up to 10 or 20,000 + + align:start position:0% +we can probably get up to 10 or 20,000 + + + align:start position:0% +we can probably get up to 10 or 20,000 +with no problem but because we assume + + align:start position:0% +with no problem but because we assume + + + align:start position:0% +with no problem but because we assume +that every client knows about every node + + align:start position:0% +that every client knows about every node + + + align:start position:0% +that every client knows about every node +and every node may be connected to every + + align:start position:0% +and every node may be connected to every + + + align:start position:0% +and every node may be connected to every +other node that's going to stop scaling + + align:start position:0% +other node that's going to stop scaling + + + align:start position:0% +other node that's going to stop scaling +before 100,000 and we need to do + + align:start position:0% +before 100,000 and we need to do + + + align:start position:0% +before 100,000 and we need to do +something about that that opens up some + + align:start position:0% +something about that that opens up some + + + align:start position:0% +something about that that opens up some +classes of attacks based on attackers + + align:start position:0% +classes of attacks based on attackers + + + align:start position:0% +classes of attacks based on attackers +learning which clients know which nodes + + align:start position:0% +learning which clients know which nodes + + + align:start position:0% +learning which clients know which nodes +and using that to distinguish clients so + + align:start position:0% +and using that to distinguish clients so + + + align:start position:0% +and using that to distinguish clients so +most of the naive approaches are a bad + + align:start position:0% +most of the naive approaches are a bad + + + align:start position:0% +most of the naive approaches are a bad +idea here but it may be that less naive + + align:start position:0% +idea here but it may be that less naive + + + align:start position:0% +idea here but it may be that less naive +approaches might work out another thing + + align:start position:0% +approaches might work out another thing + + + align:start position:0% +approaches might work out another thing +you might want to do if you're + + align:start position:0% +you might want to do if you're + + + align:start position:0% +you might want to do if you're +approaching 100,000 nodes is get rid of + + align:start position:0% +approaching 100,000 nodes is get rid of + + + align:start position:0% +approaching 100,000 nodes is get rid of +those centralized directory authorities + + align:start position:0% +those centralized directory authorities + + + align:start position:0% +those centralized directory authorities +and go to some kind of peer-to-peer + + align:start position:0% +and go to some kind of peer-to-peer + + + align:start position:0% +and go to some kind of peer-to-peer +design I don't have extremely high + + align:start position:0% +design I don't have extremely high + + + align:start position:0% +design I don't have extremely high +confidence in the peer-to-peer designs I + + align:start position:0% +confidence in the peer-to-peer designs I + + + align:start position:0% +confidence in the peer-to-peer designs I +know of so far + + align:start position:0% +know of so far + + + align:start position:0% +know of so far +but it could be that somebody's about to + + align:start position:0% +but it could be that somebody's about to + + + align:start position:0% +but it could be that somebody's about to +invent the next good one um let's see I + + align:start position:0% +invent the next good one um let's see I + + + align:start position:0% +invent the next good one um let's see I +don't know what that means oh um + + align:start position:0% +don't know what that means oh um + + + align:start position:0% +don't know what that means oh um +somebody asked a question about adding + + align:start position:0% +somebody asked a question about adding + + + align:start position:0% +somebody asked a question about adding +padding traffic or fake traffic to try + + align:start position:0% +padding traffic or fake traffic to try + + + align:start position:0% +padding traffic or fake traffic to try +to + + align:start position:0% +to + + + align:start position:0% +to +deceive um end to- end traffic + + align:start position:0% +deceive um end to- end traffic + + + align:start position:0% +deceive um end to- end traffic +correlation this is an exciting research + + align:start position:0% +correlation this is an exciting research + + + align:start position:0% +correlation this is an exciting research +field that needs someone smarter to work + + align:start position:0% +field that needs someone smarter to work + + + align:start position:0% +field that needs someone smarter to work +on it or someone with a more practical + + align:start position:0% +on it or someone with a more practical + + + align:start position:0% +on it or someone with a more practical +attitude to work on it than has + + align:start position:0% +attitude to work on it than has + + + align:start position:0% +attitude to work on it than has +previously worked on it too many of the + + align:start position:0% +previously worked on it too many of the + + + align:start position:0% +previously worked on it too many of the +results in the research literature there + + align:start position:0% +results in the research literature there + + + align:start position:0% +results in the research literature there +are only about + + align:start position:0% +are only about + + + align:start position:0% +are only about +like distinguishing the traffic of two + + align:start position:0% +like distinguishing the traffic of two + + + align:start position:0% +like distinguishing the traffic of two +users on a network containing one relay + + align:start position:0% +users on a network containing one relay + + + align:start position:0% +users on a network containing one relay +because that's how the math was easy to + + align:start position:0% +because that's how the math was easy to + + + align:start position:0% +because that's how the math was easy to +do instead but so because of this kind + + align:start position:0% +do instead but so because of this kind + + + align:start position:0% +do instead but so because of this kind +of stuff all of the traffic analysis + + align:start position:0% +of stuff all of the traffic analysis + + + align:start position:0% +of stuff all of the traffic analysis +defenses that we know of in this area + + align:start position:0% +defenses that we know of in this area + + + align:start position:0% +defenses that we know of in this area +that are still compatible with web + + align:start position:0% +that are still compatible with web + + + align:start position:0% +that are still compatible with web +browsing they sound good on if you read + + align:start position:0% +browsing they sound good on if you read + + + align:start position:0% +browsing they sound good on if you read +the abstract they'll say hooray this one + + align:start position:0% +the abstract they'll say hooray this one + + + align:start position:0% +the abstract they'll say hooray this one +makes the forces the attacker to gather + + align:start position:0% +makes the forces the attacker to gather + + + align:start position:0% +makes the forces the attacker to gather +three times as much traffic before they + + align:start position:0% +three times as much traffic before they + + + align:start position:0% +three times as much traffic before they +can correlate users except when you + + align:start position:0% +can correlate users except when you + + + align:start position:0% +can correlate users except when you +actually read the paper previously the + + align:start position:0% +actually read the paper previously the + + + align:start position:0% +actually read the paper previously the +attacker needed 2 seconds worth of + + align:start position:0% +attacker needed 2 seconds worth of + + + align:start position:0% +attacker needed 2 seconds worth of +traffic and then they won now the they + + align:start position:0% +traffic and then they won now the they + + + align:start position:0% +traffic and then they won now the they +need six seconds that's not really a + + align:start position:0% +need six seconds that's not really a + + + align:start position:0% +need six seconds that's not really a +defense in this model + + align:start position:0% +defense in this model + + + align:start position:0% +defense in this model +although perhaps against a real Network + + align:start position:0% +although perhaps against a real Network + + + align:start position:0% +although perhaps against a real Network +the numbers would be different and it + + align:start position:0% +the numbers would be different and it + + + align:start position:0% +the numbers would be different and it +might work so we would actually like to + + align:start position:0% +might work so we would actually like to + + + align:start position:0% +might work so we would actually like to +see some stuff done with padding and + + align:start position:0% +see some stuff done with padding and + + + align:start position:0% +see some stuff done with padding and +fake traffic but we don't like to add + + align:start position:0% +fake traffic but we don't like to add + + + align:start position:0% +fake traffic but we don't like to add +Voodoo defenses that we conjecture to + + align:start position:0% +Voodoo defenses that we conjecture to + + + align:start position:0% +Voodoo defenses that we conjecture to +maybe do some good although we can't do + + align:start position:0% +maybe do some good although we can't do + + + align:start position:0% +maybe do some good although we can't do +why we actually like to have evidence + + align:start position:0% +why we actually like to have evidence + + + align:start position:0% +why we actually like to have evidence +that what we're doing is going to that + + align:start position:0% +that what we're doing is going to that + + + align:start position:0% +that what we're doing is going to that +any changes we're going to make are + + align:start position:0% +any changes we're going to make are + + + align:start position:0% +any changes we're going to make are +going to help something I think I'm out + + align:start position:0% +going to help something I think I'm out + + + align:start position:0% +going to help something I think I'm out +of time and there may be a class in here + + align:start position:0% +of time and there may be a class in here + + + align:start position:0% +of time and there may be a class in here +after + + align:start position:0% +after + + + align:start position:0% +after +there's not all right so I'm going to + + align:start position:0% +there's not all right so I'm going to + + + align:start position:0% +there's not all right so I'm going to +hang around for a while and uh thanks + + align:start position:0% +hang around for a while and uh thanks + + + align:start position:0% +hang around for a while and uh thanks +for coming to listen I would take + + align:start position:0% +for coming to listen I would take + + + align:start position:0% +for coming to listen I would take +questions now but it's 12:25 and folks + + align:start position:0% +questions now but it's 12:25 and folks + + + align:start position:0% +questions now but it's 12:25 and folks +may have another class but I'll be + + align:start position:0% +may have another class but I'll be + + + align:start position:0% +may have another class but I'll be +around and so will David thank you very + + align:start position:0% +around and so will David thank you very + + + align:start position:0% +around and so will David thank you very +much for coming + + align:start position:0% +much for coming + + + align:start position:0% +much for coming +[Applause] \ No newline at end of file diff --git a/P2hxNOFiBb4.txt b/P2hxNOFiBb4.txt new file mode 100644 index 0000000000000000000000000000000000000000..0d2d83e1810d5b7821292573918aae552863657e --- /dev/null +++ b/P2hxNOFiBb4.txt @@ -0,0 +1,8147 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT open courseware continue + + align:start position:0% +will help MIT open courseware continue + + + align:start position:0% +will help MIT open courseware continue +to offer highquality educational + + align:start position:0% +to offer highquality educational + + + align:start position:0% +to offer highquality educational +resources for free to make a donation or + + align:start position:0% +resources for free to make a donation or + + + align:start position:0% +resources for free to make a donation or +view additional materials from hundreds + + align:start position:0% +view additional materials from hundreds + + + align:start position:0% +view additional materials from hundreds +of MIT courses visit MIT opencourseware + + align:start position:0% +of MIT courses visit MIT opencourseware + + + align:start position:0% +of MIT courses visit MIT opencourseware +at + + align:start position:0% + + + + align:start position:0% + +ocw.mit.edu okay so this is the first of + + align:start position:0% +ocw.mit.edu okay so this is the first of + + + align:start position:0% +ocw.mit.edu okay so this is the first of +a couple of lectures on group Theory now + + align:start position:0% +a couple of lectures on group Theory now + + + align:start position:0% +a couple of lectures on group Theory now +most of you have seen group Theory and + + align:start position:0% +most of you have seen group Theory and + + + align:start position:0% +most of you have seen group Theory and +no group Theory and so I'm going to go + + align:start position:0% +no group Theory and so I'm going to go + + + align:start position:0% +no group Theory and so I'm going to go +very fast and uh uh I'm + + align:start position:0% +very fast and uh uh I'm + + + align:start position:0% +very fast and uh uh I'm +also probably not going to go very deep + + align:start position:0% +also probably not going to go very deep + + + align:start position:0% +also probably not going to go very deep +because it's really hard to lecture on + + align:start position:0% +because it's really hard to lecture on + + + align:start position:0% +because it's really hard to lecture on +group Theory unless you're going to do + + align:start position:0% +group Theory unless you're going to do + + + align:start position:0% +group Theory unless you're going to do +it + + align:start position:0% +it + + + align:start position:0% +it +right let me just start out with a story + + align:start position:0% +right let me just start out with a story + + + align:start position:0% +right let me just start out with a story +when I was a freshman at Amis + + align:start position:0% +when I was a freshman at Amis + + + align:start position:0% +when I was a freshman at Amis +College I my + + align:start position:0% +College I my + + + align:start position:0% +College I my +uh I ended up uh doing research for a + + align:start position:0% +uh I ended up uh doing research for a + + + align:start position:0% +uh I ended up uh doing research for a +inorganic chemist by the name of Cooper + + align:start position:0% +inorganic chemist by the name of Cooper + + + align:start position:0% +inorganic chemist by the name of Cooper +Langford and in one of my first + + align:start position:0% +Langford and in one of my first + + + align:start position:0% +Langford and in one of my first +conversations with him I don't know + + align:start position:0% +conversations with him I don't know + + + align:start position:0% +conversations with him I don't know +quite why it happened this way but he I + + align:start position:0% +quite why it happened this way but he I + + + align:start position:0% +quite why it happened this way but he I +asked him a question about uh an allow + + align:start position:0% +asked him a question about uh an allow + + + align:start position:0% +asked him a question about uh an allow +what + + align:start position:0% +what + + + align:start position:0% +what +transition uh is allowed or somehow we + + align:start position:0% +transition uh is allowed or somehow we + + + align:start position:0% +transition uh is allowed or somehow we +got to that and he took out a little + + align:start position:0% +got to that and he took out a little + + + align:start position:0% +got to that and he took out a little +scrap of paper and he did a little group + + align:start position:0% +scrap of paper and he did a little group + + + align:start position:0% +scrap of paper and he did a little group +theory on the scrap of paper and and + + align:start position:0% +theory on the scrap of paper and and + + + align:start position:0% +theory on the scrap of paper and and +said this is allowed in this is + + align:start position:0% +said this is allowed in this is + + + align:start position:0% +said this is allowed in this is +forbidden and uh I'm sure there's more + + align:start position:0% +forbidden and uh I'm sure there's more + + + align:start position:0% +forbidden and uh I'm sure there's more +to the story but I just remember that + + align:start position:0% +to the story but I just remember that + + + align:start position:0% +to the story but I just remember that +scrap of paper and being incredibly + + align:start position:0% +scrap of paper and being incredibly + + + align:start position:0% +scrap of paper and being incredibly +impressed and that's really when I + + align:start position:0% +impressed and that's really when I + + + align:start position:0% +impressed and that's really when I +decided that I wanted to be a + + align:start position:0% +decided that I wanted to be a + + + align:start position:0% +decided that I wanted to be a +spectroscopist because uh the the idea + + align:start position:0% +spectroscopist because uh the the idea + + + align:start position:0% +spectroscopist because uh the the idea +of being able to make a decision based + + align:start position:0% +of being able to make a decision based + + + align:start position:0% +of being able to make a decision based +on something you can scribble on a piece + + align:start position:0% +on something you can scribble on a piece + + + align:start position:0% +on something you can scribble on a piece +of paper which was not obvious uh really + + align:start position:0% +of paper which was not obvious uh really + + + align:start position:0% +of paper which was not obvious uh really +appealed to me so this is uh how you do + + align:start position:0% +appealed to me so this is uh how you do + + + align:start position:0% +appealed to me so this is uh how you do +that and uh so let's talk about uh uh + + align:start position:0% +that and uh so let's talk about uh uh + + + align:start position:0% +that and uh so let's talk about uh uh +why we want group Theory um we'd like to + + align:start position:0% +why we want group Theory um we'd like to + + + align:start position:0% +why we want group Theory um we'd like to +be able to know about uh selection + + align:start position:0% + + + + align:start position:0% + +rules because everything we do in + + align:start position:0% +rules because everything we do in + + + align:start position:0% +rules because everything we do in +quantum mechanics involves setting up + + align:start position:0% +quantum mechanics involves setting up + + + align:start position:0% +quantum mechanics involves setting up +some kind of a + + align:start position:0% +some kind of a + + + align:start position:0% +some kind of a +matrix uh to represent the structure of + + align:start position:0% +matrix uh to represent the structure of + + + align:start position:0% +matrix uh to represent the structure of +a system or to calculate transition + + align:start position:0% +a system or to calculate transition + + + align:start position:0% +a system or to calculate transition +which transitions are allowed and uh so + + align:start position:0% +which transitions are allowed and uh so + + + align:start position:0% +which transitions are allowed and uh so +we we need to have something that's uh + + align:start position:0% +we we need to have something that's uh + + + align:start position:0% +we we need to have something that's uh +um a generalization on + + align:start position:0% +um a generalization on + + + align:start position:0% +um a generalization on +even versus odd + + align:start position:0% + + + + align:start position:0% + +integrand and so group theory is that + + align:start position:0% +integrand and so group theory is that + + + align:start position:0% +integrand and so group theory is that +generalization + + align:start position:0% +generalization + + + align:start position:0% +generalization +um we'd also like to be able + + align:start position:0% +um we'd also like to be able + + + align:start position:0% +um we'd also like to be able +to uh construct + + align:start position:0% + + + + align:start position:0% + +like to be able to construct functions + + align:start position:0% +like to be able to construct functions + + + align:start position:0% +like to be able to construct functions +which have well- defined symmetry + + align:start position:0% +which have well- defined symmetry + + + align:start position:0% +which have well- defined symmetry +classifications and so projection + + align:start position:0% +classifications and so projection + + + align:start position:0% +classifications and so projection +operators are a convenient way of doing + + align:start position:0% +operators are a convenient way of doing + + + align:start position:0% +operators are a convenient way of doing +that uh one of the main things we're + + align:start position:0% +that uh one of the main things we're + + + align:start position:0% +that uh one of the main things we're +going to do in today's lecture is set up + + align:start position:0% +going to do in today's lecture is set up + + + align:start position:0% +going to do in today's lecture is set up +the structure that enables us to say + + align:start position:0% +the structure that enables us to say + + + align:start position:0% +the structure that enables us to say +what is the uh + + align:start position:0% +what is the uh + + + align:start position:0% +what is the uh +nature of of + + align:start position:0% +nature of of + + + align:start position:0% +nature of of +molecular + + align:start position:0% + + + + align:start position:0% + +vibrations so starting out with a + + align:start position:0% +vibrations so starting out with a + + + align:start position:0% +vibrations so starting out with a +picture of the molecule you + + align:start position:0% +picture of the molecule you + + + align:start position:0% +picture of the molecule you +know uh what the geometric structure is + + align:start position:0% +know uh what the geometric structure is + + + align:start position:0% +know uh what the geometric structure is +or might be and sometimes the issue is + + align:start position:0% +or might be and sometimes the issue is + + + align:start position:0% +or might be and sometimes the issue is +well how do we decide among possible + + align:start position:0% +well how do we decide among possible + + + align:start position:0% +well how do we decide among possible +geometric structures qualitatively + + align:start position:0% +geometric structures qualitatively + + + align:start position:0% +geometric structures qualitatively +different ones is there something about + + align:start position:0% +different ones is there something about + + + align:start position:0% +different ones is there something about +the different qual ative structures that + + align:start position:0% +the different qual ative structures that + + + align:start position:0% +the different qual ative structures that +uh provides an + + align:start position:0% +uh provides an + + + align:start position:0% +uh provides an +unambiguous experimental observable that + + align:start position:0% +unambiguous experimental observable that + + + align:start position:0% +unambiguous experimental observable that +says this is + + align:start position:0% +says this is + + + align:start position:0% +says this is +d3h uh uh and uh is d3h a + + align:start position:0% +d3h uh uh and uh is d3h a + + + align:start position:0% +d3h uh uh and uh is d3h a +possibility is that a legal + + align:start position:0% +possibility is that a legal + + + align:start position:0% +possibility is that a legal +C3 c3h is a possibility D3 I don't know + + align:start position:0% +C3 c3h is a possibility D3 I don't know + + + align:start position:0% +C3 c3h is a possibility D3 I don't know +uh + + align:start position:0% +uh + + + align:start position:0% +uh +but you you decide between various + + align:start position:0% +but you you decide between various + + + align:start position:0% +but you you decide between various +qualitative + + align:start position:0% +qualitative + + + align:start position:0% +qualitative +geometries and uh + + align:start position:0% +geometries and uh + + + align:start position:0% +geometries and uh +so this lecture is about how do we use + + align:start position:0% +so this lecture is about how do we use + + + align:start position:0% +so this lecture is about how do we use +group Theory + + align:start position:0% +group Theory + + + align:start position:0% +group Theory +to construct and + + align:start position:0% +to construct and + + + align:start position:0% +to construct and +reduce reducible representations which + + align:start position:0% +reduce reducible representations which + + + align:start position:0% +reduce reducible representations which +contain information about what a + + align:start position:0% +contain information about what a + + + align:start position:0% +contain information about what a +molecule can do to irreducible + + align:start position:0% +molecule can do to irreducible + + + align:start position:0% +molecule can do to irreducible +representations that are the more + + align:start position:0% +representations that are the more + + + align:start position:0% +representations that are the more +fundament are the fundamental symmetry + + align:start position:0% +fundament are the fundamental symmetry + + + align:start position:0% +fundament are the fundamental symmetry +species of the various vibrations and + + align:start position:0% +species of the various vibrations and + + + align:start position:0% +species of the various vibrations and +there's all sorts of wonderful tricks + + align:start position:0% +there's all sorts of wonderful tricks + + + align:start position:0% +there's all sorts of wonderful tricks +involved okay so we're off to the + + align:start position:0% + + + + align:start position:0% + +races and so we know that if we have + + align:start position:0% +races and so we know that if we have + + + align:start position:0% +races and so we know that if we have +some operator that commutes with the + + align:start position:0% +some operator that commutes with the + + + align:start position:0% +some operator that commutes with the +hamiltonian then we can simplify the + + align:start position:0% +hamiltonian then we can simplify the + + + align:start position:0% +hamiltonian then we can simplify the +hamiltonian by constructing igen + + align:start position:0% +hamiltonian by constructing igen + + + align:start position:0% +hamiltonian by constructing igen +functions of this simpler operator + + align:start position:0% +functions of this simpler operator + + + align:start position:0% +functions of this simpler operator +because that will enable us to block + + align:start position:0% +because that will enable us to block + + + align:start position:0% +because that will enable us to block +diagonalize the + + align:start position:0% + + + + align:start position:0% + +hamiltonian now there's three different + + align:start position:0% +hamiltonian now there's three different + + + align:start position:0% +hamiltonian now there's three different +levels one is the full hamiltonian + + align:start position:0% +levels one is the full hamiltonian + + + align:start position:0% +levels one is the full hamiltonian +commuting with some + + align:start position:0% +commuting with some + + + align:start position:0% +commuting with some +operator and these are rigorous + + align:start position:0% +operator and these are rigorous + + + align:start position:0% +operator and these are rigorous +symmetries and they're not that many of + + align:start position:0% +symmetries and they're not that many of + + + align:start position:0% +symmetries and they're not that many of +them and usually they're pretty + + align:start position:0% +them and usually they're pretty + + + align:start position:0% +them and usually they're pretty +obvious uh and that's nice but we'd like + + align:start position:0% +obvious uh and that's nice but we'd like + + + align:start position:0% +obvious uh and that's nice but we'd like +to do more often we have some sort of + + align:start position:0% +to do more often we have some sort of + + + align:start position:0% +to do more often we have some sort of +zero order hamiltonian + + align:start position:0% +zero order hamiltonian + + + align:start position:0% +zero order hamiltonian +some + + align:start position:0% +some + + + align:start position:0% +some +approximation and those things generally + + align:start position:0% +approximation and those things generally + + + align:start position:0% +approximation and those things generally +have more Symmetry and it's easier to + + align:start position:0% +have more Symmetry and it's easier to + + + align:start position:0% +have more Symmetry and it's easier to +find operators that commute with the + + align:start position:0% +find operators that commute with the + + + align:start position:0% +find operators that commute with the +zero order hamiltonian and so this + + align:start position:0% +zero order hamiltonian and so this + + + align:start position:0% +zero order hamiltonian and so this +provides a a path towards constructing + + align:start position:0% +provides a a path towards constructing + + + align:start position:0% +provides a a path towards constructing +complete basis + + align:start position:0% +complete basis + + + align:start position:0% +complete basis +sets then there's a third + + align:start position:0% + + + + align:start position:0% + +thing and uh in + + align:start position:0% +thing and uh in + + + align:start position:0% +thing and uh in +particular C2 AB + + align:start position:0% + + + + align:start position:0% + +C it's always true that the rotational + + align:start position:0% +C it's always true that the rotational + + + align:start position:0% +C it's always true that the rotational +hamiltonian uh commutes with C2 + + align:start position:0% +hamiltonian uh commutes with C2 + + + align:start position:0% +hamiltonian uh commutes with C2 +rotations about the a b or c + + align:start position:0% +rotations about the a b or c + + + align:start position:0% +rotations about the a b or c +axes doesn't matter what the molecular + + align:start position:0% +axes doesn't matter what the molecular + + + align:start position:0% +axes doesn't matter what the molecular +symmetry + + align:start position:0% +symmetry + + + align:start position:0% +symmetry +is the rotational hamiltonian which is + + align:start position:0% +is the rotational hamiltonian which is + + + align:start position:0% +is the rotational hamiltonian which is +expressed in terms of uh uh + + align:start position:0% +expressed in terms of uh uh + + + align:start position:0% +expressed in terms of uh uh +angular momenta + + align:start position:0% +angular momenta + + + align:start position:0% +angular momenta +components multiplying reciprocal + + align:start position:0% +components multiplying reciprocal + + + align:start position:0% +components multiplying reciprocal +inertial tensor + + align:start position:0% +inertial tensor + + + align:start position:0% +inertial tensor +elements uh in the principal axis system + + align:start position:0% +elements uh in the principal axis system + + + align:start position:0% +elements uh in the principal axis system +in the principal axis system the + + align:start position:0% +in the principal axis system the + + + align:start position:0% +in the principal axis system the +rotational uh hamiltonan looks like a + + align:start position:0% +rotational uh hamiltonan looks like a + + + align:start position:0% +rotational uh hamiltonan looks like a +football or a + + align:start position:0% +football or a + + + align:start position:0% +football or a +frisbee doesn't matter whether it's a + + align:start position:0% +frisbee doesn't matter whether it's a + + + align:start position:0% +frisbee doesn't matter whether it's a +symmetric or asymmetric top and you know + + align:start position:0% +symmetric or asymmetric top and you know + + + align:start position:0% +symmetric or asymmetric top and you know +that you take either one of those things + + align:start position:0% +that you take either one of those things + + + align:start position:0% +that you take either one of those things +and it's going to be uh uh it's going to + + align:start position:0% +and it's going to be uh uh it's going to + + + align:start position:0% +and it's going to be uh uh it's going to +have C2 symmetry about any axis and so + + align:start position:0% +have C2 symmetry about any axis and so + + + align:start position:0% +have C2 symmetry about any axis and so +the rotational hamiltonian is going to + + align:start position:0% +the rotational hamiltonian is going to + + + align:start position:0% +the rotational hamiltonian is going to +commute with all these things so there + + align:start position:0% +commute with all these things so there + + + align:start position:0% +commute with all these things so there +is going to be group + + align:start position:0% +is going to be group + + + align:start position:0% +is going to be group +theoretical uh features of rotational + + align:start position:0% +theoretical uh features of rotational + + + align:start position:0% +theoretical uh features of rotational +levels which are + + align:start position:0% + + + + align:start position:0% + +Universal and uh in addition to the + + align:start position:0% +Universal and uh in addition to the + + + align:start position:0% +Universal and uh in addition to the +group theoretical characteristics of uh + + align:start position:0% +group theoretical characteristics of uh + + + align:start position:0% +group theoretical characteristics of uh +the vibrations and translations + + align:start position:0% +the vibrations and translations + + + align:start position:0% +the vibrations and translations +okay yes is that true even if you have + + align:start position:0% +okay yes is that true even if you have + + + align:start position:0% +okay yes is that true even if you have +um axis switching like lude vibrations + + align:start position:0% +um axis switching like lude vibrations + + + align:start position:0% +um axis switching like lude vibrations +and like that to the best of my + + align:start position:0% +and like that to the best of my + + + align:start position:0% +and like that to the best of my +knowledge that well there's a + + align:start position:0% +knowledge that well there's a + + + align:start position:0% +knowledge that well there's a +problem + + align:start position:0% +problem + + + align:start position:0% +problem +uh okay no let me + + align:start position:0% +uh okay no let me + + + align:start position:0% +uh okay no let me +just if we use symmetric + + align:start position:0% +just if we use symmetric + + + align:start position:0% +just if we use symmetric +tops symmetric top basis set then this + + align:start position:0% +tops symmetric top basis set then this + + + align:start position:0% +tops symmetric top basis set then this +is true uh if we have asymmetric tops we + + align:start position:0% +is true uh if we have asymmetric tops we + + + align:start position:0% +is true uh if we have asymmetric tops we +Express the asymmetric top uh functions + + align:start position:0% +Express the asymmetric top uh functions + + + align:start position:0% +Express the asymmetric top uh functions +in terms of linear combinations of + + align:start position:0% +in terms of linear combinations of + + + align:start position:0% +in terms of linear combinations of +symmetric top basis functions and so if + + align:start position:0% +symmetric top basis functions and so if + + + align:start position:0% +symmetric top basis functions and so if +we can classify the symmetric top + + align:start position:0% +we can classify the symmetric top + + + align:start position:0% +we can classify the symmetric top +functions we can classify the asymmetric + + align:start position:0% +functions we can classify the asymmetric + + + align:start position:0% +functions we can classify the asymmetric +top now uh when you talked about large + + align:start position:0% +top now uh when you talked about large + + + align:start position:0% +top now uh when you talked about large +amplitude motion where you're blurring + + align:start position:0% +amplitude motion where you're blurring + + + align:start position:0% +amplitude motion where you're blurring +the distinction between rotation and + + align:start position:0% +the distinction between rotation and + + + align:start position:0% +the distinction between rotation and +vibration I'm still talking about basis + + align:start position:0% +vibration I'm still talking about basis + + + align:start position:0% +vibration I'm still talking about basis +functions and the ability to classify + + align:start position:0% +functions and the ability to classify + + + align:start position:0% +functions and the ability to classify +basis functions + + align:start position:0% +basis functions + + + align:start position:0% +basis functions +and I think that I'd better stop talking + + align:start position:0% +and I think that I'd better stop talking + + + align:start position:0% +and I think that I'd better stop talking +about this because I'm going to end up + + align:start position:0% +about this because I'm going to end up + + + align:start position:0% +about this because I'm going to end up +muddying the + + align:start position:0% +muddying the + + + align:start position:0% +muddying the +water okay so we have this now there's a + + align:start position:0% +water okay so we have this now there's a + + + align:start position:0% +water okay so we have this now there's a +whole bunch we start out and we talk + + align:start position:0% +whole bunch we start out and we talk + + + align:start position:0% +whole bunch we start out and we talk +about Point groups everybody learns + + align:start position:0% +about Point groups everybody learns + + + align:start position:0% +about Point groups everybody learns +group Theory from the point of view of + + align:start position:0% +group Theory from the point of view of + + + align:start position:0% +group Theory from the point of view of +Point groups and point groups are a + + align:start position:0% +Point groups and point groups are a + + + align:start position:0% +Point groups and point groups are a +useful way of dealing with rigid objects + + align:start position:0% +useful way of dealing with rigid objects + + + align:start position:0% +useful way of dealing with rigid objects +uh + + align:start position:0% +uh + + + align:start position:0% +uh +and they're not + + align:start position:0% +and they're not + + + align:start position:0% +and they're not +uh they're not useful for describing + + align:start position:0% +uh they're not useful for describing + + + align:start position:0% +uh they're not useful for describing +large amplitude motions or transitions + + align:start position:0% +large amplitude motions or transitions + + + align:start position:0% +large amplitude motions or transitions +between uh St electronic states where + + align:start position:0% +between uh St electronic states where + + + align:start position:0% +between uh St electronic states where +molecules have different shapes + + align:start position:0% +molecules have different shapes + + + align:start position:0% +molecules have different shapes +qualitative shapes a point group is + + align:start position:0% +qualitative shapes a point group is + + + align:start position:0% +qualitative shapes a point group is +called a point group because it consists + + align:start position:0% +called a point group because it consists + + + align:start position:0% +called a point group because it consists +of a bunch of symmetry operations + + align:start position:0% +of a bunch of symmetry operations + + + align:start position:0% +of a bunch of symmetry operations +rotations reflection planes + + align:start position:0% +rotations reflection planes + + + align:start position:0% +rotations reflection planes +uh uh in centers of inversion where all + + align:start position:0% +uh uh in centers of inversion where all + + + align:start position:0% +uh uh in centers of inversion where all +of + + align:start position:0% +of + + + align:start position:0% +of +these uh symmetry operations intersect + + align:start position:0% +these uh symmetry operations intersect + + + align:start position:0% +these uh symmetry operations intersect +with or contain one + + align:start position:0% + + + + align:start position:0% + +point the real symmetries in molecules + + align:start position:0% +point the real symmetries in molecules + + + align:start position:0% +point the real symmetries in molecules +are uh the complete nuclear permutation + + align:start position:0% +are uh the complete nuclear permutation + + + align:start position:0% +are uh the complete nuclear permutation +inversion group nuclear permutations you + + align:start position:0% +inversion group nuclear permutations you + + + align:start position:0% +inversion group nuclear permutations you +have identical nuclei you can permute + + align:start position:0% +have identical nuclei you can permute + + + align:start position:0% +have identical nuclei you can permute +them those have to correspond to + + align:start position:0% +them those have to correspond to + + + align:start position:0% +them those have to correspond to +rigorous symmetries and there's a center + + align:start position:0% +rigorous symmetries and there's a center + + + align:start position:0% +rigorous symmetries and there's a center +there is a uh an inversion symmetry not + + align:start position:0% +there is a uh an inversion symmetry not + + + align:start position:0% +there is a uh an inversion symmetry not +in the body but with respect to the + + align:start position:0% +in the body but with respect to the + + + align:start position:0% +in the body but with respect to the +laboratory and so these are the rigorous + + align:start position:0% +laboratory and so these are the rigorous + + + align:start position:0% +laboratory and so these are the rigorous +symmetry elements now a subset of the + + align:start position:0% +symmetry elements now a subset of the + + + align:start position:0% +symmetry elements now a subset of the +permutations that are possible in a + + align:start position:0% +permutations that are possible in a + + + align:start position:0% +permutations that are possible in a +molecule are not + + align:start position:0% +molecule are not + + + align:start position:0% +molecule are not +feasible because in order to permute + + align:start position:0% +feasible because in order to permute + + + align:start position:0% +feasible because in order to permute +those two things you have to break bonds + + align:start position:0% +those two things you have to break bonds + + + align:start position:0% +those two things you have to break bonds +and so it requires going over a very + + align:start position:0% +and so it requires going over a very + + + align:start position:0% +and so it requires going over a very +high barrier they're not feasible so we + + align:start position:0% +high barrier they're not feasible so we + + + align:start position:0% +high barrier they're not feasible so we +forget about them but that corresponds + + align:start position:0% +forget about them but that corresponds + + + align:start position:0% +forget about them but that corresponds +to a degeneracy or there you have to + + align:start position:0% +to a degeneracy or there you have to + + + align:start position:0% +to a degeneracy or there you have to +somehow build a picture which + + align:start position:0% +somehow build a picture which + + + align:start position:0% +somehow build a picture which +incorporates those nonfeasible + + align:start position:0% +incorporates those nonfeasible + + + align:start position:0% +incorporates those nonfeasible +permutations + + align:start position:0% + + + + align:start position:0% + +so so if we exclude those we get What's + + align:start position:0% +so so if we exclude those we get What's + + + align:start position:0% +so so if we exclude those we get What's +called the molecular symmetry group + + align:start position:0% +called the molecular symmetry group + + + align:start position:0% +called the molecular symmetry group +group and the molecular symmetry group + + align:start position:0% +group and the molecular symmetry group + + + align:start position:0% +group and the molecular symmetry group +is isomorphic with the point + + align:start position:0% +is isomorphic with the point + + + align:start position:0% +is isomorphic with the point +group and + + align:start position:0% +group and + + + align:start position:0% +group and +so uh you can usually use Point + + align:start position:0% +so uh you can usually use Point + + + align:start position:0% +so uh you can usually use Point +group + + align:start position:0% +group + + + align:start position:0% +group +operations Point group + + align:start position:0% +operations Point group + + + align:start position:0% +operations Point group +ideas uh even though they are an + + align:start position:0% +ideas uh even though they are an + + + align:start position:0% +ideas uh even though they are an +approximation however when you have + + align:start position:0% +approximation however when you have + + + align:start position:0% +approximation however when you have +really high exitation really large + + align:start position:0% +really high exitation really large + + + align:start position:0% +really high exitation really large +amplitude motions + + align:start position:0% +amplitude motions + + + align:start position:0% +amplitude motions +uh they become more and more of the + + align:start position:0% +uh they become more and more of the + + + align:start position:0% +uh they become more and more of the +elements of the cnpi group that become + + align:start position:0% +elements of the cnpi group that become + + + align:start position:0% +elements of the cnpi group that become +feasible become relevant and levels + + align:start position:0% +feasible become relevant and levels + + + align:start position:0% +feasible become relevant and levels +which you when you when you say I've + + align:start position:0% +which you when you when you say I've + + + align:start position:0% +which you when you when you say I've +neglected uh a symmetry operation + + align:start position:0% +neglected uh a symmetry operation + + + align:start position:0% +neglected uh a symmetry operation +because it's non feasible that really + + align:start position:0% +because it's non feasible that really + + + align:start position:0% +because it's non feasible that really +means that the levels are have a + + align:start position:0% +means that the levels are have a + + + align:start position:0% +means that the levels are have a +built-in this the energy states have a + + align:start position:0% +built-in this the energy states have a + + + align:start position:0% +built-in this the energy states have a +built-in + + align:start position:0% +built-in + + + align:start position:0% +built-in +degeneracy and when what had been + + align:start position:0% +degeneracy and when what had been + + + align:start position:0% +degeneracy and when what had been +non-feasible becomes feasible some of + + align:start position:0% +non-feasible becomes feasible some of + + + align:start position:0% +non-feasible becomes feasible some of +that degeneracy gets lifted and that's + + align:start position:0% +that degeneracy gets lifted and that's + + + align:start position:0% +that degeneracy gets lifted and that's +really what we're interested when we're + + align:start position:0% +really what we're interested when we're + + + align:start position:0% +really what we're interested when we're +looking at bond-breaking isomerization + + align:start position:0% +looking at bond-breaking isomerization + + + align:start position:0% +looking at bond-breaking isomerization +because nothing could be more not + + align:start position:0% +because nothing could be more not + + + align:start position:0% +because nothing could be more not +feasible than Breaking + + align:start position:0% +feasible than Breaking + + + align:start position:0% +feasible than Breaking +bonds and so + + align:start position:0% +bonds and so + + + align:start position:0% +bonds and so +uh you have to get used to the idea that + + align:start position:0% +uh you have to get used to the idea that + + + align:start position:0% +uh you have to get used to the idea that +if you + + align:start position:0% +if you + + + align:start position:0% +if you +neglected a rigorous + + align:start position:0% +neglected a rigorous + + + align:start position:0% +neglected a rigorous +symmetry you have said I'm going to + + align:start position:0% +symmetry you have said I'm going to + + + align:start position:0% +symmetry you have said I'm going to +treat a state as if it were non- + + align:start position:0% +treat a state as if it were non- + + + align:start position:0% +treat a state as if it were non- +degenerate and you can get away with + + align:start position:0% +degenerate and you can get away with + + + align:start position:0% +degenerate and you can get away with +that + + align:start position:0% +that + + + align:start position:0% +that +until that uh non-feasible operation + + align:start position:0% +until that uh non-feasible operation + + + align:start position:0% +until that uh non-feasible operation +becomes relevant so we have the + + align:start position:0% +becomes relevant so we have the + + + align:start position:0% +becomes relevant so we have the +molecular symmetry group and that takes + + align:start position:0% +molecular symmetry group and that takes + + + align:start position:0% +molecular symmetry group and that takes +us back to the point group and usually + + align:start position:0% +us back to the point group and usually + + + align:start position:0% +us back to the point group and usually +there are no surprises if you started + + align:start position:0% +there are no surprises if you started + + + align:start position:0% +there are no surprises if you started +out with with ordinary Point group group + + align:start position:0% +out with with ordinary Point group group + + + align:start position:0% +out with with ordinary Point group group +Theory you can + + align:start position:0% +Theory you can + + + align:start position:0% +Theory you can +classify uh your States quite well but + + align:start position:0% +classify uh your States quite well but + + + align:start position:0% +classify uh your States quite well but +you still have problems when you're + + align:start position:0% +you still have problems when you're + + + align:start position:0% +you still have problems when you're +facing transitions between electronic + + align:start position:0% +facing transitions between electronic + + + align:start position:0% +facing transitions between electronic +states where the equilibrium geometry is + + align:start position:0% +states where the equilibrium geometry is + + + align:start position:0% +states where the equilibrium geometry is +associated with different point groups + + align:start position:0% +associated with different point groups + + + align:start position:0% +associated with different point groups +and there are a lot of ad hoc ways of + + align:start position:0% +and there are a lot of ad hoc ways of + + + align:start position:0% +and there are a lot of ad hoc ways of +trying to find your way + + align:start position:0% +trying to find your way + + + align:start position:0% +trying to find your way +around uh you know what when you're + + align:start position:0% +around uh you know what when you're + + + align:start position:0% +around uh you know what when you're +going from a higher symmetry to a lower + + align:start position:0% +going from a higher symmetry to a lower + + + align:start position:0% +going from a higher symmetry to a lower +symmetry it's usually possible to sort + + align:start position:0% +symmetry it's usually possible to sort + + + align:start position:0% +symmetry it's usually possible to sort +of your way through this but + + align:start position:0% +of your way through this but + + + align:start position:0% +of your way through this but +when you're going say between a c2h and + + align:start position:0% +when you're going say between a c2h and + + + align:start position:0% +when you're going say between a c2h and +a c2v two groups that have the + + align:start position:0% +a c2v two groups that have the + + + align:start position:0% +a c2v two groups that have the +same + + align:start position:0% +same + + + align:start position:0% +same +dimensionality uh when you're doing that + + align:start position:0% +dimensionality uh when you're doing that + + + align:start position:0% +dimensionality uh when you're doing that +you really have to be careful and it's + + align:start position:0% +you really have to be careful and it's + + + align:start position:0% +you really have to be careful and it's +there that keeping track of the + + align:start position:0% +there that keeping track of the + + + align:start position:0% +there that keeping track of the +permutations and inversions provide you + + align:start position:0% +permutations and inversions provide you + + + align:start position:0% +permutations and inversions provide you +with guidance and often you have to go + + align:start position:0% +with guidance and often you have to go + + + align:start position:0% +with guidance and often you have to go +to a higher dimensional group in order + + align:start position:0% +to a higher dimensional group in order + + + align:start position:0% +to a higher dimensional group in order +to see the connection between two + + align:start position:0% +to see the connection between two + + + align:start position:0% +to see the connection between two +different point + + align:start position:0% +different point + + + align:start position:0% +different point +groups so this is a beautiful and subtle + + align:start position:0% +groups so this is a beautiful and subtle + + + align:start position:0% +groups so this is a beautiful and subtle +thing but you want to still see the + + align:start position:0% +thing but you want to still see the + + + align:start position:0% +thing but you want to still see the +beauty and power of just simple Point + + align:start position:0% +beauty and power of just simple Point + + + align:start position:0% +beauty and power of just simple Point +group group Theory and that's what I'll + + align:start position:0% +group group Theory and that's what I'll + + + align:start position:0% +group group Theory and that's what I'll +be talking about okay so I assume assum + + align:start position:0% +be talking about okay so I assume assum + + + align:start position:0% +be talking about okay so I assume assum +that everybody has seen plenty of group + + align:start position:0% +that everybody has seen plenty of group + + + align:start position:0% +that everybody has seen plenty of group +theory yes no everybody in the room if + + align:start position:0% +theory yes no everybody in the room if + + + align:start position:0% +theory yes no everybody in the room if +anybody says no I will say + + align:start position:0% +anybody says no I will say + + + align:start position:0% +anybody says no I will say +more so you've seen some group + + align:start position:0% +more so you've seen some group + + + align:start position:0% +more so you've seen some group +Theory okay well let let's just + + align:start position:0% +Theory okay well let let's just + + + align:start position:0% +Theory okay well let let's just +um let's just touch on some high points + + align:start position:0% +um let's just touch on some high points + + + align:start position:0% +um let's just touch on some high points +so we have symmetry operations rotations + + align:start position:0% +so we have symmetry operations rotations + + + align:start position:0% +so we have symmetry operations rotations +are uh denoted with a Capital C and an n + + align:start position:0% +are uh denoted with a Capital C and an n + + + align:start position:0% +are uh denoted with a Capital C and an n +n is the order of the rotation and so if + + align:start position:0% +n is the order of the rotation and so if + + + align:start position:0% +n is the order of the rotation and so if +uh you rotate by pi to uh if that's a + + align:start position:0% +uh you rotate by pi to uh if that's a + + + align:start position:0% +uh you rotate by pi to uh if that's a +symmetry operation that's C2 if you + + align:start position:0% +symmetry operation that's C2 if you + + + align:start position:0% +symmetry operation that's C2 if you +rotate by uh 2 pi over 3 that's C3 the + + align:start position:0% +rotate by uh 2 pi over 3 that's C3 the + + + align:start position:0% +rotate by uh 2 pi over 3 that's C3 the +number of clicks + + align:start position:0% +number of clicks + + + align:start position:0% +number of clicks +along a complete rotation so there are + + align:start position:0% +along a complete rotation so there are + + + align:start position:0% +along a complete rotation so there are +various + + align:start position:0% +various + + + align:start position:0% +various +CNS uh there are planes of symmetry all + + align:start position:0% +CNS uh there are planes of symmetry all + + + align:start position:0% +CNS uh there are planes of symmetry all +of which are called Sigma and there are + + align:start position:0% +of which are called Sigma and there are + + + align:start position:0% +of which are called Sigma and there are +two kinds well there are three kinds of + + align:start position:0% +two kinds well there are three kinds of + + + align:start position:0% +two kinds well there are three kinds of +sigmas Sigma V + + align:start position:0% +sigmas Sigma V + + + align:start position:0% +sigmas Sigma V +Sigma H and sigma + + align:start position:0% +Sigma H and sigma + + + align:start position:0% +Sigma H and sigma +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +D most of the Symmetry planes that we + + align:start position:0% +D most of the Symmetry planes that we + + + align:start position:0% +D most of the Symmetry planes that we +see are Sigma V this is a plane that + + align:start position:0% +see are Sigma V this is a plane that + + + align:start position:0% +see are Sigma V this is a plane that +contains the highest order + + align:start position:0% +contains the highest order + + + align:start position:0% +contains the highest order +rotation so uh high order rotation + + align:start position:0% +rotation so uh high order rotation + + + align:start position:0% +rotation so uh high order rotation +Benzene is C6 has a has a C6 rotation + + align:start position:0% +Benzene is C6 has a has a C6 rotation + + + align:start position:0% +Benzene is C6 has a has a C6 rotation +and so Sigma V we always draw the + + align:start position:0% +and so Sigma V we always draw the + + + align:start position:0% +and so Sigma V we always draw the +rotation axis like this and sigma V is a + + align:start position:0% +rotation axis like this and sigma V is a + + + align:start position:0% +rotation axis like this and sigma V is a +vertical plane Sigma H is a horizontal + + align:start position:0% +vertical plane Sigma H is a horizontal + + + align:start position:0% +vertical plane Sigma H is a horizontal +plane and uh Sigma D is a vertical plane + + align:start position:0% +plane and uh Sigma D is a vertical plane + + + align:start position:0% +plane and uh Sigma D is a vertical plane +uh which + + align:start position:0% +uh which + + + align:start position:0% +uh which +bcts uh perpendicular C2 + + align:start position:0% +bcts uh perpendicular C2 + + + align:start position:0% +bcts uh perpendicular C2 +axis so we have those things then we + + align:start position:0% +axis so we have those things then we + + + align:start position:0% +axis so we have those things then we +have I I is inversion in the body + + align:start position:0% +have I I is inversion in the body + + + align:start position:0% +have I I is inversion in the body +frame and that's different from Big I + + align:start position:0% +frame and that's different from Big I + + + align:start position:0% +frame and that's different from Big I +which is inversion in the laboratory and + + align:start position:0% +which is inversion in the laboratory and + + + align:start position:0% +which is inversion in the laboratory and +people do confuse those and uh uh this + + align:start position:0% +people do confuse those and uh uh this + + + align:start position:0% +people do confuse those and uh uh this +has to do with parody and this has to do + + align:start position:0% +has to do with parody and this has to do + + + align:start position:0% +has to do with parody and this has to do +with gu Symmetry and it's very very it's + + align:start position:0% +with gu Symmetry and it's very very it's + + + align:start position:0% +with gu Symmetry and it's very very it's +almost as bad as saying nuclear to get + + align:start position:0% +almost as bad as saying nuclear to get + + + align:start position:0% +almost as bad as saying nuclear to get +to call the Symmetry species associated + + align:start position:0% +to call the Symmetry species associated + + + align:start position:0% +to call the Symmetry species associated +with little I uh as + + align:start position:0% + + + + align:start position:0% + +parody and it's very common okay stop me + + align:start position:0% +parody and it's very common okay stop me + + + align:start position:0% +parody and it's very common okay stop me +I mean this is really + + align:start position:0% +I mean this is really + + + align:start position:0% +I mean this is really +uh you're you're you're sitting here I I + + align:start position:0% +uh you're you're you're sitting here I I + + + align:start position:0% +uh you're you're you're sitting here I I +want you to you know to know all of the + + align:start position:0% +want you to you know to know all of the + + + align:start position:0% +want you to you know to know all of the +actors there's also improper + + align:start position:0% +actors there's also improper + + + align:start position:0% +actors there's also improper +rotations well I should also say c i is + + align:start position:0% +rotations well I should also say c i is + + + align:start position:0% +rotations well I should also say c i is +the same thing as I have to uh look at + + align:start position:0% +the same thing as I have to uh look at + + + align:start position:0% +the same thing as I have to uh look at +that C2 time Sigma + + align:start position:0% + + + + align:start position:0% + +H and uh so but s SN is + + align:start position:0% +H and uh so but s SN is + + + align:start position:0% +H and uh so but s SN is +CN Sigma H now often you have a this + + align:start position:0% +CN Sigma H now often you have a this + + + align:start position:0% +CN Sigma H now often you have a this +called an improper rotation often you + + align:start position:0% +called an improper rotation often you + + + align:start position:0% +called an improper rotation often you +have a higher order improper rotation + + align:start position:0% +have a higher order improper rotation + + + align:start position:0% +have a higher order improper rotation +than proper rotation so CN doesn't have + + align:start position:0% +than proper rotation so CN doesn't have + + + align:start position:0% +than proper rotation so CN doesn't have +to be a symmetry but the product of two + + align:start position:0% +to be a symmetry but the product of two + + + align:start position:0% +to be a symmetry but the product of two +would be that and so uh the inversion is + + align:start position:0% +would be that and so uh the inversion is + + + align:start position:0% +would be that and so uh the inversion is +S2 but we always give it a special name + + align:start position:0% +S2 but we always give it a special name + + + align:start position:0% +S2 but we always give it a special name +and certain symmetry operations can + + align:start position:0% +and certain symmetry operations can + + + align:start position:0% +and certain symmetry operations can +commute with each other and others don't + + align:start position:0% +commute with each other and others don't + + + align:start position:0% +commute with each other and others don't +and you have to be careful about that + + align:start position:0% +and you have to be careful about that + + + align:start position:0% +and you have to be careful about that +Reflections and uh + + align:start position:0% +Reflections and uh + + + align:start position:0% +Reflections and uh +rotations generally commute but uh at + + align:start position:0% +rotations generally commute but uh at + + + align:start position:0% +rotations generally commute but uh at +least these two commute um + + align:start position:0% +least these two commute um + + + align:start position:0% +least these two commute um +so okay so we have a + + align:start position:0% +so okay so we have a + + + align:start position:0% +so okay so we have a +group and some of the properties of a + + align:start position:0% +group and some of the properties of a + + + align:start position:0% +group and some of the properties of a +group are + + align:start position:0% + + + + align:start position:0% + +closure so we have a bunch of symmetry + + align:start position:0% +closure so we have a bunch of symmetry + + + align:start position:0% +closure so we have a bunch of symmetry +operations + + align:start position:0% +operations + + + align:start position:0% +operations +R and we can multiply R1 * + + align:start position:0% +R and we can multiply R1 * + + + align:start position:0% +R and we can multiply R1 * +R2 and when you do that you get always + + align:start position:0% +R2 and when you do that you get always + + + align:start position:0% +R2 and when you do that you get always +another symmetry operation in the group + + align:start position:0% +another symmetry operation in the group + + + align:start position:0% +another symmetry operation in the group +so there is a multiplication table among + + align:start position:0% +so there is a multiplication table among + + + align:start position:0% +so there is a multiplication table among +all the + + align:start position:0% +all the + + + align:start position:0% +all the +symmetries which is complete you can + + align:start position:0% +symmetries which is complete you can + + + align:start position:0% +symmetries which is complete you can +never get something outside the + + align:start position:0% +never get something outside the + + + align:start position:0% +never get something outside the +group and if you have uh R1 R2 R3 you + + align:start position:0% +group and if you have uh R1 R2 R3 you + + + align:start position:0% +group and if you have uh R1 R2 R3 you +can put parentheses around any two + + align:start position:0% +can put parentheses around any two + + + align:start position:0% +can put parentheses around any two +um there's also an + + align:start position:0% + + + + align:start position:0% + +inverse so every + + align:start position:0% +inverse so every + + + align:start position:0% +inverse so every +operation in a group in a symmetry group + + align:start position:0% +operation in a group in a symmetry group + + + align:start position:0% +operation in a group in a symmetry group +has to have an + + align:start position:0% + + + + align:start position:0% + +inverse and so we have uh um and there + + align:start position:0% +inverse and so we have uh um and there + + + align:start position:0% +inverse and so we have uh um and there +is also an identity operation which is + + align:start position:0% +is also an identity operation which is + + + align:start position:0% +is also an identity operation which is +usually denoted e but sometimes I I is + + align:start position:0% +usually denoted e but sometimes I I is + + + align:start position:0% +usually denoted e but sometimes I I is +dangerous because I means something else + + align:start position:0% +dangerous because I means something else + + + align:start position:0% +dangerous because I means something else +but not in point group land but e also + + align:start position:0% +but not in point group land but e also + + + align:start position:0% +but not in point group land but e also +means other things + + align:start position:0% +means other things + + + align:start position:0% +means other things +yeah so uh okay so there's a little bit + + align:start position:0% +yeah so uh okay so there's a little bit + + + align:start position:0% +yeah so uh okay so there's a little bit +of heterogeneity about uh um um notation + + align:start position:0% +of heterogeneity about uh um um notation + + + align:start position:0% +of heterogeneity about uh um um notation +but there's an awful lot of universality + + align:start position:0% +but there's an awful lot of universality + + + align:start position:0% +but there's an awful lot of universality +okay so + + align:start position:0% + + + + align:start position:0% + +now you look at a molecule and you + + align:start position:0% +now you look at a molecule and you + + + align:start position:0% +now you look at a molecule and you +classify it + + align:start position:0% + + + + align:start position:0% + +according to symmetry operations + + align:start position:0% +according to symmetry operations + + + align:start position:0% +according to symmetry operations +present + + align:start position:0% +present + + + align:start position:0% +present +now a symmetry operation is one where if + + align:start position:0% +now a symmetry operation is one where if + + + align:start position:0% +now a symmetry operation is one where if +you apply it to the + + align:start position:0% +you apply it to the + + + align:start position:0% +you apply it to the +molecule well uh let me say it + + align:start position:0% +molecule well uh let me say it + + + align:start position:0% +molecule well uh let me say it +again you look at the molecule you leave + + align:start position:0% +again you look at the molecule you leave + + + align:start position:0% +again you look at the molecule you leave +the room somebody your friend applies a + + align:start position:0% +the room somebody your friend applies a + + + align:start position:0% +the room somebody your friend applies a +symmetry operation to the molecule you + + align:start position:0% +symmetry operation to the molecule you + + + align:start position:0% +symmetry operation to the molecule you +come back back you can't tell that + + align:start position:0% +come back back you can't tell that + + + align:start position:0% +come back back you can't tell that +anything + + align:start position:0% +anything + + + align:start position:0% +anything +happened so you classify the molecule + + align:start position:0% +happened so you classify the molecule + + + align:start position:0% +happened so you classify the molecule +According to which symmetry operations + + align:start position:0% +According to which symmetry operations + + + align:start position:0% +According to which symmetry operations +exist and that enables you to to + + align:start position:0% +exist and that enables you to to + + + align:start position:0% +exist and that enables you to to +identify the point group and there is a + + align:start position:0% +identify the point group and there is a + + + align:start position:0% +identify the point group and there is a +logical procedure for doing that uh and + + align:start position:0% +logical procedure for doing that uh and + + + align:start position:0% +logical procedure for doing that uh and +that logical procedure is uh a table in + + align:start position:0% +that logical procedure is uh a table in + + + align:start position:0% +that logical procedure is uh a table in +bernat's book and you can do it it's + + align:start position:0% +bernat's book and you can do it it's + + + align:start position:0% +bernat's book and you can do it it's +it's a usually we deal with such low + + align:start position:0% +it's a usually we deal with such low + + + align:start position:0% +it's a usually we deal with such low +order groups that it's not not a very + + align:start position:0% +order groups that it's not not a very + + + align:start position:0% +order groups that it's not not a very +complicated matter they're always c2h or + + align:start position:0% +complicated matter they're always c2h or + + + align:start position:0% +complicated matter they're always c2h or +c2v or + + align:start position:0% +c2v or + + + align:start position:0% +c2v or +C2 so okay so you classify the + + align:start position:0% +C2 so okay so you classify the + + + align:start position:0% +C2 so okay so you classify the +group so the next thing + + align:start position:0% +group so the next thing + + + align:start position:0% +group so the next thing +is + + align:start position:0% +is + + + align:start position:0% +is +Matrix + + align:start position:0% +Matrix + + + align:start position:0% +Matrix +representations so we have objects that + + align:start position:0% +representations so we have objects that + + + align:start position:0% +representations so we have objects that +have a multiplication + + align:start position:0% +have a multiplication + + + align:start position:0% +have a multiplication +table and uh so we'd like to represent + + align:start position:0% +table and uh so we'd like to represent + + + align:start position:0% +table and uh so we'd like to represent +these objects by matrices + + align:start position:0% +these objects by matrices + + + align:start position:0% +these objects by matrices +which have the same multiplication table + + align:start position:0% +which have the same multiplication table + + + align:start position:0% +which have the same multiplication table +now same is a complicated word because + + align:start position:0% +now same is a complicated word because + + + align:start position:0% +now same is a complicated word because +it means that there is nothing in the + + align:start position:0% +it means that there is nothing in the + + + align:start position:0% +it means that there is nothing in the +multiplication table of these + + align:start position:0% +multiplication table of these + + + align:start position:0% +multiplication table of these +matrices which would be + + align:start position:0% +matrices which would be + + + align:start position:0% +matrices which would be +untrue with respect to the + + align:start position:0% +untrue with respect to the + + + align:start position:0% +untrue with respect to the +multiplication table of the operator + + align:start position:0% +multiplication table of the operator + + + align:start position:0% +multiplication table of the operator +sometimes the multiplication table is + + align:start position:0% +sometimes the multiplication table is + + + align:start position:0% +sometimes the multiplication table is +has lost a lot of information so 1 * 1 + + align:start position:0% +has lost a lot of information so 1 * 1 + + + align:start position:0% +has lost a lot of information so 1 * 1 +is always one + + align:start position:0% +is always one + + + align:start position:0% +is always one +and you can represent a lot uh yes so uh + + align:start position:0% +and you can represent a lot uh yes so uh + + + align:start position:0% +and you can represent a lot uh yes so uh +there will be Matrix representations now + + align:start position:0% +there will be Matrix representations now + + + align:start position:0% +there will be Matrix representations now +that we're particularly interested in + + align:start position:0% + + + + align:start position:0% + +geometric + + align:start position:0% +geometric + + + align:start position:0% +geometric +Transformations so what we want to do is + + align:start position:0% +Transformations so what we want to do is + + + align:start position:0% +Transformations so what we want to do is +to to find a set of + + align:start position:0% +to to find a set of + + + align:start position:0% +to to find a set of +matrices + + align:start position:0% +matrices + + + align:start position:0% +matrices +which are equivalent to each of the + + align:start position:0% +which are equivalent to each of the + + + align:start position:0% +which are equivalent to each of the +Symmetry + + align:start position:0% + + + + align:start position:0% + +operations equivalent is a complicated + + align:start position:0% +operations equivalent is a complicated + + + align:start position:0% +operations equivalent is a complicated +thing so one way of doing that is to + + align:start position:0% +thing so one way of doing that is to + + + align:start position:0% +thing so one way of doing that is to +label each of the atoms in a molecule by + + align:start position:0% +label each of the atoms in a molecule by + + + align:start position:0% +label each of the atoms in a molecule by +three cartisian + + align:start position:0% +three cartisian + + + align:start position:0% +three cartisian +coordinates and then we + + align:start position:0% +coordinates and then we + + + align:start position:0% +coordinates and then we +build uh + + align:start position:0% +build uh + + + align:start position:0% +build uh +matrices that transform the coordinates + + align:start position:0% +matrices that transform the coordinates + + + align:start position:0% +matrices that transform the coordinates +of the + + align:start position:0% +of the + + + align:start position:0% +of the +atoms uh + + align:start position:0% +atoms uh + + + align:start position:0% +atoms uh +according to how the Symmetry operation + + align:start position:0% +according to how the Symmetry operation + + + align:start position:0% +according to how the Symmetry operation +would would move + + align:start position:0% +would would move + + + align:start position:0% +would would move +things and that's the the first thing we + + align:start position:0% +things and that's the the first thing we + + + align:start position:0% +things and that's the the first thing we +do we're going to do but the nice thing + + align:start position:0% +do we're going to do but the nice thing + + + align:start position:0% +do we're going to do but the nice thing +about this is + + align:start position:0% +about this is + + + align:start position:0% +about this is +that when we create this 3-end + + align:start position:0% +that when we create this 3-end + + + align:start position:0% +that when we create this 3-end +dimensional + + align:start position:0% +dimensional + + + align:start position:0% +dimensional +representation of the group by uh + + align:start position:0% +representation of the group by uh + + + align:start position:0% +representation of the group by uh +building geometric transformations of + + align:start position:0% +building geometric transformations of + + + align:start position:0% +building geometric transformations of +the 3n cartisian coordinates that + + align:start position:0% +the 3n cartisian coordinates that + + + align:start position:0% +the 3n cartisian coordinates that +correspond to the an + + align:start position:0% +correspond to the an + + + align:start position:0% +correspond to the an +atoms + + align:start position:0% + + + + align:start position:0% + +uh we're going to want to throw away a + + align:start position:0% +uh we're going to want to throw away a + + + align:start position:0% +uh we're going to want to throw away a +lot of + + align:start position:0% +lot of + + + align:start position:0% +lot of +information and this is the beauty of it + + align:start position:0% +information and this is the beauty of it + + + align:start position:0% +information and this is the beauty of it +and this is why my friend Mr + + align:start position:0% +and this is why my friend Mr + + + align:start position:0% +and this is why my friend Mr +Langford uh was able to do this + + align:start position:0% +Langford uh was able to do this + + + align:start position:0% +Langford uh was able to do this +incredible calculation on a little tiny + + align:start position:0% +incredible calculation on a little tiny + + + align:start position:0% +incredible calculation on a little tiny +scrap of paper because we don't care + + align:start position:0% +scrap of paper because we don't care + + + align:start position:0% +scrap of paper because we don't care +about the + + align:start position:0% +about the + + + align:start position:0% +about the +matrices we care about their tra es they + + align:start position:0% +matrices we care about their tra es they + + + align:start position:0% +matrices we care about their tra es they +are characters and there's powerful + + align:start position:0% +are characters and there's powerful + + + align:start position:0% +are characters and there's powerful +things so so what we're going to do + + align:start position:0% +things so so what we're going to do + + + align:start position:0% +things so so what we're going to do +instead of well first we're going to + + align:start position:0% +instead of well first we're going to + + + align:start position:0% +instead of well first we're going to +actually find solve for some of the + + align:start position:0% +actually find solve for some of the + + + align:start position:0% +actually find solve for some of the +matrices but then we're going to learn + + align:start position:0% +matrices but then we're going to learn + + + align:start position:0% +matrices but then we're going to learn +some tricks for what do we really need + + align:start position:0% +some tricks for what do we really need + + + align:start position:0% +some tricks for what do we really need +to know to determine the thing we we + + align:start position:0% +to know to determine the thing we we + + + align:start position:0% +to know to determine the thing we we +really need to know the characters and + + align:start position:0% +really need to know the characters and + + + align:start position:0% +really need to know the characters and +that's much much less and one can + + align:start position:0% +that's much much less and one can + + + align:start position:0% +that's much much less and one can +without being good at uh uh at + + align:start position:0% +without being good at uh uh at + + + align:start position:0% +without being good at uh uh at +geometry uh one can very quickly work + + align:start position:0% +geometry uh one can very quickly work + + + align:start position:0% +geometry uh one can very quickly work +out how to calculate the + + align:start position:0% +out how to calculate the + + + align:start position:0% +out how to calculate the +characters the traces of the matrixes + + align:start position:0% +characters the traces of the matrixes + + + align:start position:0% +characters the traces of the matrixes +that we + + align:start position:0% +that we + + + align:start position:0% +that we +need okay so now I have to do some + + align:start position:0% +need okay so now I have to do some + + + align:start position:0% +need okay so now I have to do some +formal stuff which I don't like very + + align:start position:0% +formal stuff which I don't like very + + + align:start position:0% +formal stuff which I don't like very +much because I often get confused let's + + align:start position:0% +much because I often get confused let's + + + align:start position:0% +much because I often get confused let's +do + + align:start position:0% + + + + align:start position:0% + +this + + align:start position:0% +this + + + align:start position:0% +this +so here is a vector we represented by x + + align:start position:0% +so here is a vector we represented by x + + + align:start position:0% +so here is a vector we represented by x +y + + align:start position:0% +y + + + align:start position:0% +y +z and uh + + align:start position:0% +z and uh + + + align:start position:0% +z and uh +but we can choose a better + + align:start position:0% +but we can choose a better + + + align:start position:0% +but we can choose a better +representation we can we can say this is + + align:start position:0% +representation we can we can say this is + + + align:start position:0% +representation we can we can say this is +X1 E1 unit Factor X2 + + align:start position:0% +X1 E1 unit Factor X2 + + + align:start position:0% +X1 E1 unit Factor X2 +E2 X3 + + align:start position:0% +E2 X3 + + + align:start position:0% +E2 X3 +E3 so E1 E2 and + + align:start position:0% +E3 so E1 E2 and + + + align:start position:0% +E3 so E1 E2 and +E3 Define an axis + + align:start position:0% +E3 Define an axis + + + align:start position:0% +E3 Define an axis +system and X1 X2 and X3 are the uh the + + align:start position:0% +system and X1 X2 and X3 are the uh the + + + align:start position:0% +system and X1 X2 and X3 are the uh the +coordinates in that that axis + + align:start position:0% +coordinates in that that axis + + + align:start position:0% +coordinates in that that axis +system and so we can write this as some + + align:start position:0% +system and so we can write this as some + + + align:start position:0% +system and so we can write this as some +of i x i EI I + + align:start position:0% +of i x i EI I + + + align:start position:0% +of i x i EI I +hat now + + align:start position:0% +hat now + + + align:start position:0% +hat now +uh suppose we have some symmetry + + align:start position:0% +uh suppose we have some symmetry + + + align:start position:0% +uh suppose we have some symmetry +operation operating on X1 X2 + + align:start position:0% +operation operating on X1 X2 + + + align:start position:0% +operation operating on X1 X2 +X3 well that will give us X1 Prime x 2 + + align:start position:0% +X3 well that will give us X1 Prime x 2 + + + align:start position:0% +X3 well that will give us X1 Prime x 2 +Prime X3 Prime + + align:start position:0% +Prime X3 Prime + + + align:start position:0% +Prime X3 Prime +and so we want to find the + + align:start position:0% +and so we want to find the + + + align:start position:0% +and so we want to find the +Matrix that represents this symmetry + + align:start position:0% +Matrix that represents this symmetry + + + align:start position:0% +Matrix that represents this symmetry +operation that when applied to X1 X2 X3 + + align:start position:0% +operation that when applied to X1 X2 X3 + + + align:start position:0% +operation that when applied to X1 X2 X3 +gives us X1 Prime X2 Prime X3 Prime so + + align:start position:0% +gives us X1 Prime X2 Prime X3 Prime so + + + align:start position:0% +gives us X1 Prime X2 Prime X3 Prime so +we want to find this Matrix that does + + align:start position:0% + + + + align:start position:0% + +that + + align:start position:0% + + + + align:start position:0% + +so I guess I don't need to + + align:start position:0% + + + + align:start position:0% + +so suppose we're interested in the + + align:start position:0% +so suppose we're interested in the + + + align:start position:0% +so suppose we're interested in the +plane that contains X1 and + + align:start position:0% +plane that contains X1 and + + + align:start position:0% +plane that contains X1 and +X2 well what does that + + align:start position:0% +X2 well what does that + + + align:start position:0% +X2 well what does that +do uh well the plane that contains X1 + + align:start position:0% +do uh well the plane that contains X1 + + + align:start position:0% +do uh well the plane that contains X1 +and X2 takes X1 into X1 X2 into X2 and + + align:start position:0% +and X2 takes X1 into X1 X2 into X2 and + + + align:start position:0% +and X2 takes X1 into X1 X2 into X2 and +X3 into - + + align:start position:0% +X3 into - + + + align:start position:0% +X3 into - +X3 + + align:start position:0% +X3 + + + align:start position:0% +X3 +so + + align:start position:0% +so + + + align:start position:0% +so +d sigma1 + + align:start position:0% +d sigma1 + + + align:start position:0% +d sigma1 +2 is equal to 1 0 0 0 1 0 0 0 - + + align:start position:0% + + + + align:start position:0% + +one so simply by knowing what each of + + align:start position:0% +one so simply by knowing what each of + + + align:start position:0% +one so simply by knowing what each of +the Symmetry operation does to + + align:start position:0% +the Symmetry operation does to + + + align:start position:0% +the Symmetry operation does to +coordinates uh you can work out uh the + + align:start position:0% +coordinates uh you can work out uh the + + + align:start position:0% +coordinates uh you can work out uh the +matrices and so this + + align:start position:0% +matrices and so this + + + align:start position:0% +matrices and so this +is um and we could also uh work out + + align:start position:0% +is um and we could also uh work out + + + align:start position:0% +is um and we could also uh work out +suppose we have a rotation by Theta + + align:start position:0% +suppose we have a rotation by Theta + + + align:start position:0% +suppose we have a rotation by Theta +about the X3 + + align:start position:0% +about the X3 + + + align:start position:0% +about the X3 +axis so what would that do well if we + + align:start position:0% +axis so what would that do well if we + + + align:start position:0% +axis so what would that do well if we +rotate about the X3 axis X3 goes into X3 + + align:start position:0% +rotate about the X3 axis X3 goes into X3 + + + align:start position:0% +rotate about the X3 axis X3 goes into X3 +but X1 and + + align:start position:0% +but X1 and + + + align:start position:0% +but X1 and +X2 get mixed up and so we can write this + + align:start position:0% +X2 get mixed up and so we can write this + + + align:start position:0% +X2 get mixed up and so we can write this +as cosine and why we don't need to write + + align:start position:0% +as cosine and why we don't need to write + + + align:start position:0% +as cosine and why we don't need to write +all three letters cosine Theta sin Theta + + align:start position:0% +all three letters cosine Theta sin Theta + + + align:start position:0% +all three letters cosine Theta sin Theta +0 minus sin Theta cosine Theta 0 0 0 1 + + align:start position:0% +0 minus sin Theta cosine Theta 0 0 0 1 + + + align:start position:0% +0 minus sin Theta cosine Theta 0 0 0 1 +so you can work + + align:start position:0% +so you can work + + + align:start position:0% +so you can work +out uh what various operations + + align:start position:0% + + + + align:start position:0% + +do well I said that you have to have an + + align:start position:0% +do well I said that you have to have an + + + align:start position:0% +do well I said that you have to have an +inverse of every operation so what does + + align:start position:0% +inverse of every operation so what does + + + align:start position:0% +inverse of every operation so what does +the inverse of this look like so what + + align:start position:0% +the inverse of this look like so what + + + align:start position:0% +the inverse of this look like so what +transformation would do that so we have + + align:start position:0% +transformation would do that so we have + + + align:start position:0% +transformation would do that so we have +c c theta 3 + + align:start position:0% + + + + align:start position:0% + +minus one what would that do what would + + align:start position:0% +minus one what would that do what would + + + align:start position:0% +minus one what would that do what would +that so instead of rotating by Theta we + + align:start position:0% +that so instead of rotating by Theta we + + + align:start position:0% +that so instead of rotating by Theta we +rotate by minus + + align:start position:0% +rotate by minus + + + align:start position:0% +rotate by minus +Theta cosiness don't change they don't + + align:start position:0% +Theta cosiness don't change they don't + + + align:start position:0% +Theta cosiness don't change they don't +care about plus Theta to minus Theta but + + align:start position:0% +care about plus Theta to minus Theta but + + + align:start position:0% +care about plus Theta to minus Theta but +SS do and so we get C Theta minus s + + align:start position:0% +SS do and so we get C Theta minus s + + + align:start position:0% +SS do and so we get C Theta minus s +Theta s Theta C Theta + + align:start position:0% + + + + align:start position:0% + +1 notice that this + + align:start position:0% +1 notice that this + + + align:start position:0% +1 notice that this +is the transpose of + + align:start position:0% + + + + align:start position:0% + +that notice also that the rows and + + align:start position:0% +that notice also that the rows and + + + align:start position:0% +that notice also that the rows and +columns are + + align:start position:0% +columns are + + + align:start position:0% +columns are +normalized to one and the rows and + + align:start position:0% +normalized to one and the rows and + + + align:start position:0% +normalized to one and the rows and +columns are mutually + + align:start position:0% + + + + align:start position:0% + +orthogonal those are the properties of a + + align:start position:0% +orthogonal those are the properties of a + + + align:start position:0% +orthogonal those are the properties of a +unitary Matrix + + align:start position:0% +unitary Matrix + + + align:start position:0% +unitary Matrix +we know if we have a unitary + + align:start position:0% +we know if we have a unitary + + + align:start position:0% +we know if we have a unitary +Matrix + + align:start position:0% +Matrix + + + align:start position:0% +Matrix +uh we if we want to perform a similarity + + align:start position:0% +uh we if we want to perform a similarity + + + align:start position:0% +uh we if we want to perform a similarity +transformation we know that's a + + align:start position:0% +transformation we know that's a + + + align:start position:0% +transformation we know that's a +similarity transformation on some uh + + align:start position:0% + + + + align:start position:0% + +um + + align:start position:0% + + + + align:start position:0% + +that it's easy to perform a similarity + + align:start position:0% +that it's easy to perform a similarity + + + align:start position:0% +that it's easy to perform a similarity +transformation which involves + + align:start position:0% +transformation which involves + + + align:start position:0% +transformation which involves +sandwiching and operator between U and U + + align:start position:0% +sandwiching and operator between U and U + + + align:start position:0% +sandwiching and operator between U and U +uus one and U if it's if the + + align:start position:0% +uus one and U if it's if the + + + align:start position:0% +uus one and U if it's if the +transformation operator is unitary then + + align:start position:0% +transformation operator is unitary then + + + align:start position:0% +transformation operator is unitary then +you can get the inverse simply by taking + + align:start position:0% +you can get the inverse simply by taking + + + align:start position:0% +you can get the inverse simply by taking +the conjugate transpose if the operator + + align:start position:0% +the conjugate transpose if the operator + + + align:start position:0% +the conjugate transpose if the operator +is uh if the Matrix is real then you + + align:start position:0% +is uh if the Matrix is real then you + + + align:start position:0% +is uh if the Matrix is real then you +don't need the conjugate transpose you + + align:start position:0% +don't need the conjugate transpose you + + + align:start position:0% +don't need the conjugate transpose you +just need the transpose and so uh u- one + + align:start position:0% +just need the transpose and so uh u- one + + + align:start position:0% +just need the transpose and so uh u- one +is equal to U dagger uh U sorry + + align:start position:0% +is equal to U dagger uh U sorry + + + align:start position:0% +is equal to U dagger uh U sorry +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so we' we know an awful lot we have + + align:start position:0% +so we' we know an awful lot we have + + + align:start position:0% +so we' we know an awful lot we have +Transformations + + align:start position:0% +Transformations + + + align:start position:0% +Transformations +among uh on operators we have + + align:start position:0% +among uh on operators we have + + + align:start position:0% +among uh on operators we have +multiplication of + + align:start position:0% +multiplication of + + + align:start position:0% +multiplication of +operators um we know that the Matrix + + align:start position:0% +operators um we know that the Matrix + + + align:start position:0% +operators um we know that the Matrix +representations have to be + + align:start position:0% +representations have to be + + + align:start position:0% +representations have to be +unitary and we know about un Norm what + + align:start position:0% +unitary and we know about un Norm what + + + align:start position:0% +unitary and we know about un Norm what +unitary is normaliz normalization and + + align:start position:0% +unitary is normaliz normalization and + + + align:start position:0% +unitary is normaliz normalization and +orthogonal okay + + align:start position:0% + + + + align:start position:0% + +okay so + + align:start position:0% +okay so + + + align:start position:0% +okay so +now we're beginning to we're ready to be + + align:start position:0% +now we're beginning to we're ready to be + + + align:start position:0% +now we're beginning to we're ready to be +able to set up Matrix + + align:start position:0% +able to set up Matrix + + + align:start position:0% +able to set up Matrix +representations for of symmetry + + align:start position:0% +representations for of symmetry + + + align:start position:0% +representations for of symmetry +operations on a + + align:start position:0% +operations on a + + + align:start position:0% +operations on a +molecule + + align:start position:0% +molecule + + + align:start position:0% +molecule +uh using anything about the molecule + + align:start position:0% +uh using anything about the molecule + + + align:start position:0% +uh using anything about the molecule +that we want to use to generate a + + align:start position:0% +that we want to use to generate a + + + align:start position:0% +that we want to use to generate a +representation so + + align:start position:0% + + + + align:start position:0% + +uh we uh attach to the molecule a bunch + + align:start position:0% +uh we uh attach to the molecule a bunch + + + align:start position:0% +uh we uh attach to the molecule a bunch +of bases + + align:start position:0% +of bases + + + align:start position:0% +of bases +vectors so at each atom or Each Bond any + + align:start position:0% +vectors so at each atom or Each Bond any + + + align:start position:0% +vectors so at each atom or Each Bond any +play anything we want to do I mean for + + align:start position:0% +play anything we want to do I mean for + + + align:start position:0% +play anything we want to do I mean for +example for + + align:start position:0% + + + + align:start position:0% + +Benzene we could we could uh we can be + + align:start position:0% +Benzene we could we could uh we can be + + + align:start position:0% +Benzene we could we could uh we can be +really + + align:start position:0% +really + + + align:start position:0% +really +masochistic and + + align:start position:0% +masochistic and + + + align:start position:0% +masochistic and +have 3 n uh three cartisian coordinates + + align:start position:0% +have 3 n uh three cartisian coordinates + + + align:start position:0% +have 3 n uh three cartisian coordinates +for each hydrogen and for each carbon or + + align:start position:0% +for each hydrogen and for each carbon or + + + align:start position:0% +for each hydrogen and for each carbon or +we can say I'm only going to be + + align:start position:0% +we can say I'm only going to be + + + align:start position:0% +we can say I'm only going to be +interested in these six + + align:start position:0% +interested in these six + + + align:start position:0% +interested in these six +bonds or in these six + + align:start position:0% +bonds or in these six + + + align:start position:0% +bonds or in these six +bonds or I'm going to uh look at + + align:start position:0% +bonds or I'm going to uh look at + + + align:start position:0% +bonds or I'm going to uh look at +perpendicular uh I'm going to uh I'm + + align:start position:0% +perpendicular uh I'm going to uh I'm + + + align:start position:0% +perpendicular uh I'm going to uh I'm +going to look at motions of the carbon + + align:start position:0% +going to look at motions of the carbon + + + align:start position:0% +going to look at motions of the carbon +atom perpendicular to the plane and + + align:start position:0% +atom perpendicular to the plane and + + + align:start position:0% +atom perpendicular to the plane and +there's six of them or I'm looking at I + + align:start position:0% +there's six of them or I'm looking at I + + + align:start position:0% +there's six of them or I'm looking at I +can look at the hydro motions of the + + align:start position:0% +can look at the hydro motions of the + + + align:start position:0% +can look at the hydro motions of the +hydrogen atom perpendicular to the plane + + align:start position:0% +hydrogen atom perpendicular to the plane + + + align:start position:0% +hydrogen atom perpendicular to the plane +or + + align:start position:0% +or + + + align:start position:0% +or +bending anything you want and it doesn't + + align:start position:0% +bending anything you want and it doesn't + + + align:start position:0% +bending anything you want and it doesn't +have to be linearly + + align:start position:0% + + + + align:start position:0% + +independent you can just dress up the + + align:start position:0% +independent you can just dress up the + + + align:start position:0% +independent you can just dress up the +molecule with a bunch of + + align:start position:0% +molecule with a bunch of + + + align:start position:0% +molecule with a bunch of +things that you're going to transform + + align:start position:0% +things that you're going to transform + + + align:start position:0% +things that you're going to transform +using the Symmetry + + align:start position:0% +using the Symmetry + + + align:start position:0% +using the Symmetry +operations and then using the + + align:start position:0% +operations and then using the + + + align:start position:0% +operations and then using the +simplification of not writing the uh the + + align:start position:0% +simplification of not writing the uh the + + + align:start position:0% +simplification of not writing the uh the +D + + align:start position:0% +D + + + align:start position:0% +D +matrices that affect this transformation + + align:start position:0% +matrices that affect this transformation + + + align:start position:0% +matrices that affect this transformation +but the traces of these D matrices one + + align:start position:0% +but the traces of these D matrices one + + + align:start position:0% +but the traces of these D matrices one +can do this amazingly + + align:start position:0% +can do this amazingly + + + align:start position:0% +can do this amazingly +fast and I mean if you have you know if + + align:start position:0% +fast and I mean if you have you know if + + + align:start position:0% +fast and I mean if you have you know if +you have six carboncarbon + + align:start position:0% +you have six carboncarbon + + + align:start position:0% +you have six carboncarbon +bonds uh you can't have six linearly + + align:start position:0% +bonds uh you can't have six linearly + + + align:start position:0% +bonds uh you can't have six linearly +independent Bond lengths because five of + + align:start position:0% +independent Bond lengths because five of + + + align:start position:0% +independent Bond lengths because five of +them will determine the + + align:start position:0% +them will determine the + + + align:start position:0% +them will determine the +sixth so there's going to be some + + align:start position:0% +sixth so there's going to be some + + + align:start position:0% +sixth so there's going to be some +overcompleteness about some of these + + align:start position:0% +overcompleteness about some of these + + + align:start position:0% +overcompleteness about some of these +cartoons but often you want to ask + + align:start position:0% +cartoons but often you want to ask + + + align:start position:0% +cartoons but often you want to ask +questions for example you want to ask + + align:start position:0% +questions for example you want to ask + + + align:start position:0% +questions for example you want to ask +questions how many uh how many modes are + + align:start position:0% +questions how many uh how many modes are + + + align:start position:0% +questions how many uh how many modes are +confined to a + + align:start position:0% +confined to a + + + align:start position:0% +confined to a +plane of the three n minus 6 normal + + align:start position:0% +plane of the three n minus 6 normal + + + align:start position:0% +plane of the three n minus 6 normal +modes which ones conserve planer + + align:start position:0% +modes which ones conserve planer + + + align:start position:0% +modes which ones conserve planer +symmetry which modes uh uh are uniquely + + align:start position:0% +symmetry which modes uh uh are uniquely + + + align:start position:0% +symmetry which modes uh uh are uniquely +bending modes which modes don't invol + + align:start position:0% +bending modes which modes don't invol + + + align:start position:0% +bending modes which modes don't invol +you know involve hydrogens and not + + align:start position:0% +you know involve hydrogens and not + + + align:start position:0% +you know involve hydrogens and not +carbons or something like that if + + align:start position:0% +carbons or something like that if + + + align:start position:0% +carbons or something like that if +there's any well this be hard uh but any + + align:start position:0% +there's any well this be hard uh but any + + + align:start position:0% +there's any well this be hard uh but any +question you want to ask that involves + + align:start position:0% +question you want to ask that involves + + + align:start position:0% +question you want to ask that involves +classifying the normal modes according + + align:start position:0% +classifying the normal modes according + + + align:start position:0% +classifying the normal modes according +to what is their + + align:start position:0% +to what is their + + + align:start position:0% +to what is their +content you will find uh uh amazingly + + align:start position:0% +content you will find uh uh amazingly + + + align:start position:0% +content you will find uh uh amazingly +powerful uh results that come from + + align:start position:0% +powerful uh results that come from + + + align:start position:0% +powerful uh results that come from +practically + + align:start position:0% +practically + + + align:start position:0% +practically +nothing okay + + align:start position:0% + + + + align:start position:0% + +so I'm just going to skip over this + + align:start position:0% +so I'm just going to skip over this + + + align:start position:0% +so I'm just going to skip over this +active versus passive because it's been + + align:start position:0% +active versus passive because it's been + + + align:start position:0% +active versus passive because it's been +scaring me and you're going to have to + + align:start position:0% +scaring me and you're going to have to + + + align:start position:0% +scaring me and you're going to have to +sort this out for yourself + + align:start position:0% + + + + align:start position:0% + +uh and I'll start so we have matrices + + align:start position:0% +uh and I'll start so we have matrices + + + align:start position:0% +uh and I'll start so we have matrices +and we're going to simplify matrices to + + align:start position:0% + + + + align:start position:0% + +characters and uh + + align:start position:0% + + + + align:start position:0% + +so so suppose we have a 3n by 3n + + align:start position:0% +so so suppose we have a 3n by 3n + + + align:start position:0% +so so suppose we have a 3n by 3n +dimensional uh Matrix that would be the + + align:start position:0% +dimensional uh Matrix that would be the + + + align:start position:0% +dimensional uh Matrix that would be the +complete thing that you would use and + + align:start position:0% + + + + align:start position:0% + +uh so we have a matrix which will + + align:start position:0% +uh so we have a matrix which will + + + align:start position:0% +uh so we have a matrix which will +describe what any symmetry operation + + align:start position:0% +describe what any symmetry operation + + + align:start position:0% +describe what any symmetry operation +does to say the + + align:start position:0% +does to say the + + + align:start position:0% +does to say the +3n uh cartisian coordinates attached to + + align:start position:0% +3n uh cartisian coordinates attached to + + + align:start position:0% +3n uh cartisian coordinates attached to +the uh atoms and we can just take the + + align:start position:0% +the uh atoms and we can just take the + + + align:start position:0% +the uh atoms and we can just take the +sum of the diagonal elements of these + + align:start position:0% +sum of the diagonal elements of these + + + align:start position:0% +sum of the diagonal elements of these +matrices and that's called the + + align:start position:0% + + + + align:start position:0% + +character it turns out + + align:start position:0% +character it turns out + + + align:start position:0% +character it turns out +that + + align:start position:0% +that + + + align:start position:0% +that +um we I'm getting ahead of myself but I + + align:start position:0% +um we I'm getting ahead of myself but I + + + align:start position:0% +um we I'm getting ahead of myself but I +just have to say it uh what's unique + + align:start position:0% +just have to say it uh what's unique + + + align:start position:0% +just have to say it uh what's unique +about a + + align:start position:0% +about a + + + align:start position:0% +about a +matrix um suppose you have a a 3n by 3n + + align:start position:0% +matrix um suppose you have a a 3n by 3n + + + align:start position:0% +matrix um suppose you have a a 3n by 3n +dimensional Matrix well it will have 3 n + + align:start position:0% +dimensional Matrix well it will have 3 n + + + align:start position:0% +dimensional Matrix well it will have 3 n +i + + align:start position:0% + + + + align:start position:0% + +values you perform a similarity + + align:start position:0% +values you perform a similarity + + + align:start position:0% +values you perform a similarity +transformation on that Matrix it'll have + + align:start position:0% +transformation on that Matrix it'll have + + + align:start position:0% +transformation on that Matrix it'll have +the same 3n igen + + align:start position:0% +the same 3n igen + + + align:start position:0% +the same 3n igen +values the trace of a + + align:start position:0% +values the trace of a + + + align:start position:0% +values the trace of a +matrix is invariant under similarity + + align:start position:0% +matrix is invariant under similarity + + + align:start position:0% +matrix is invariant under similarity +Transformations it's just the sum of the + + align:start position:0% +Transformations it's just the sum of the + + + align:start position:0% +Transformations it's just the sum of the +I values + + align:start position:0% +I values + + + align:start position:0% +I values +the determinant of a matrix is invariant + + align:start position:0% +the determinant of a matrix is invariant + + + align:start position:0% +the determinant of a matrix is invariant +because it's the product of the igen + + align:start position:0% +because it's the product of the igen + + + align:start position:0% +because it's the product of the igen +values and so uh the + + align:start position:0% +values and so uh the + + + align:start position:0% +values and so uh the +information um that is contained in a + + align:start position:0% +information um that is contained in a + + + align:start position:0% +information um that is contained in a +matrix it may be sufficient to reduce + + align:start position:0% +matrix it may be sufficient to reduce + + + align:start position:0% +matrix it may be sufficient to reduce +our concerns to just the sum of the + + align:start position:0% +our concerns to just the sum of the + + + align:start position:0% +our concerns to just the sum of the +diagonal elements of each + + align:start position:0% + + + + align:start position:0% + +Matrix and so with that statement I'm + + align:start position:0% +Matrix and so with that statement I'm + + + align:start position:0% +Matrix and so with that statement I'm +going to to make the + + align:start position:0% +going to to make the + + + align:start position:0% +going to to make the +bold and useful comment that okay how do + + align:start position:0% +bold and useful comment that okay how do + + + align:start position:0% +bold and useful comment that okay how do +we construct a 3n dimensional + + align:start position:0% +we construct a 3n dimensional + + + align:start position:0% +we construct a 3n dimensional +representation of a molecule where the + + align:start position:0% +representation of a molecule where the + + + align:start position:0% +representation of a molecule where the +atoms are not all located at the + + align:start position:0% +atoms are not all located at the + + + align:start position:0% +atoms are not all located at the +center so the first thing that you do is + + align:start position:0% +center so the first thing that you do is + + + align:start position:0% +center so the first thing that you do is +you say Okay suppose atom Alpha and atom + + align:start position:0% +you say Okay suppose atom Alpha and atom + + + align:start position:0% +you say Okay suppose atom Alpha and atom +beta are + + align:start position:0% + + + + align:start position:0% + +exchanged by the Symmetry operation + + align:start position:0% + + + + align:start position:0% + +well the Matrix that does that is going + + align:start position:0% +well the Matrix that does that is going + + + align:start position:0% +well the Matrix that does that is going +to have an alpha block and a beta + + align:start position:0% +to have an alpha block and a beta + + + align:start position:0% +to have an alpha block and a beta +block and in between there's an alpha + + align:start position:0% +block and in between there's an alpha + + + align:start position:0% +block and in between there's an alpha +beta + + align:start position:0% +beta + + + align:start position:0% +beta +block and uh + + align:start position:0% +block and uh + + + align:start position:0% +block and uh +so all the information about the + + align:start position:0% +so all the information about the + + + align:start position:0% +so all the information about the +exchange of Alpha and beta are out + + align:start position:0% + + + + align:start position:0% + +here so if Alpha and beta are + + align:start position:0% +here so if Alpha and beta are + + + align:start position:0% +here so if Alpha and beta are +exchanged the coordinates of Alpha and + + align:start position:0% +exchanged the coordinates of Alpha and + + + align:start position:0% +exchanged the coordinates of Alpha and +the coordinates of beta do not + + align:start position:0% +the coordinates of beta do not + + + align:start position:0% +the coordinates of beta do not +contribute to the uh + + align:start position:0% +contribute to the uh + + + align:start position:0% +contribute to the uh +trace this is the most wonderful thing + + align:start position:0% +trace this is the most wonderful thing + + + align:start position:0% +trace this is the most wonderful thing +because it enables you to look at a + + align:start position:0% +because it enables you to look at a + + + align:start position:0% +because it enables you to look at a +molecule and almost all the Symmetry + + align:start position:0% +molecule and almost all the Symmetry + + + align:start position:0% +molecule and almost all the Symmetry +operations + + align:start position:0% +operations + + + align:start position:0% +operations +involve exchanges of + + align:start position:0% +involve exchanges of + + + align:start position:0% +involve exchanges of +atoms in fact uh only the atoms that lie + + align:start position:0% +atoms in fact uh only the atoms that lie + + + align:start position:0% +atoms in fact uh only the atoms that lie +on a symmetry element like in a plane or + + align:start position:0% +on a symmetry element like in a plane or + + + align:start position:0% +on a symmetry element like in a plane or +along along + + align:start position:0% +along along + + + align:start position:0% +along along +a a rotation Axis or at the center of + + align:start position:0% +a a rotation Axis or at the center of + + + align:start position:0% +a a rotation Axis or at the center of +inversion only those + + align:start position:0% +inversion only those + + + align:start position:0% +inversion only those +atoms uh you have to worry about all the + + align:start position:0% +atoms uh you have to worry about all the + + + align:start position:0% +atoms uh you have to worry about all the +atoms that are + + align:start position:0% +atoms that are + + + align:start position:0% +atoms that are +permuted they don't contribute to the + + align:start position:0% +permuted they don't contribute to the + + + align:start position:0% +permuted they don't contribute to the +trace of this D Matrix for that symmetry + + align:start position:0% +trace of this D Matrix for that symmetry + + + align:start position:0% +trace of this D Matrix for that symmetry +operation and so you can forget about + + align:start position:0% +operation and so you can forget about + + + align:start position:0% +operation and so you can forget about +them and that's + + align:start position:0% +them and that's + + + align:start position:0% +them and that's +fantastic + + align:start position:0% + + + + align:start position:0% + +so um + + align:start position:0% + + + + align:start position:0% + +so all you need is a small number of uh + + align:start position:0% +so all you need is a small number of uh + + + align:start position:0% +so all you need is a small number of uh +3x3 matrices that describe what each of + + align:start position:0% +3x3 matrices that describe what each of + + + align:start position:0% +3x3 matrices that describe what each of +the Symmetry operations will do to atoms + + align:start position:0% +the Symmetry operations will do to atoms + + + align:start position:0% +the Symmetry operations will do to atoms +that are located in a plane or on a on + + align:start position:0% +that are located in a plane or on a on + + + align:start position:0% +that are located in a plane or on a on +the rotation axis and you already know + + align:start position:0% +the rotation axis and you already know + + + align:start position:0% +the rotation axis and you already know +that you could work that out yourself so + + align:start position:0% +that you could work that out yourself so + + + align:start position:0% +that you could work that out yourself so +you don't have to be good at uh at + + align:start position:0% +you don't have to be good at uh at + + + align:start position:0% +you don't have to be good at uh at +geometry to figure out what would how to + + align:start position:0% +geometry to figure out what would how to + + + align:start position:0% +geometry to figure out what would how to +write this block in this Matrix because + + align:start position:0% +write this block in this Matrix because + + + align:start position:0% +write this block in this Matrix because +it's + + align:start position:0% + + + + align:start position:0% + +irrelevant + + align:start position:0% +irrelevant + + + align:start position:0% +irrelevant +so we're going to use a picture of the + + align:start position:0% +so we're going to use a picture of the + + + align:start position:0% +so we're going to use a picture of the +molecule to + + align:start position:0% +molecule to + + + align:start position:0% +molecule to +generate what we call a reducible + + align:start position:0% +generate what we call a reducible + + + align:start position:0% +generate what we call a reducible +representation and this reducible repes + + align:start position:0% +representation and this reducible repes + + + align:start position:0% +representation and this reducible repes +representation will be uh a collection + + align:start position:0% +representation will be uh a collection + + + align:start position:0% +representation will be uh a collection +of D matrices corresponding to the + + align:start position:0% +of D matrices corresponding to the + + + align:start position:0% +of D matrices corresponding to the +different symmetry operations + + align:start position:0% + + + + align:start position:0% + +okay so this we have a all of the + + align:start position:0% +okay so this we have a all of the + + + align:start position:0% +okay so this we have a all of the +Symmetry + + align:start position:0% +Symmetry + + + align:start position:0% +Symmetry +operations and each one is represented + + align:start position:0% +operations and each one is represented + + + align:start position:0% +operations and each one is represented +by a matrix which has the same + + align:start position:0% +by a matrix which has the same + + + align:start position:0% +by a matrix which has the same +Dimension different + + align:start position:0% + + + + align:start position:0% + +matrices + + align:start position:0% +matrices + + + align:start position:0% +matrices +now we can write this reducible Matrix + + align:start position:0% +now we can write this reducible Matrix + + + align:start position:0% +now we can write this reducible Matrix +as a sum of what we call + + align:start position:0% +as a sum of what we call + + + align:start position:0% +as a sum of what we call +irreducible uh + + align:start position:0% + + + + align:start position:0% + +representations which just corresponds + + align:start position:0% +representations which just corresponds + + + align:start position:0% +representations which just corresponds +to basically block + + align:start position:0% + + + + align:start position:0% + +diagonalizing all of the uh the + + align:start position:0% +diagonalizing all of the uh the + + + align:start position:0% +diagonalizing all of the uh the +Transformations uh so each one of these + + align:start position:0% +Transformations uh so each one of these + + + align:start position:0% +Transformations uh so each one of these +matrices gets Block diagonalized in + + align:start position:0% +matrices gets Block diagonalized in + + + align:start position:0% +matrices gets Block diagonalized in +exactly the same way now you don't know + + align:start position:0% +exactly the same way now you don't know + + + align:start position:0% +exactly the same way now you don't know +that that's guaranteed and the only way + + align:start position:0% +that that's guaranteed and the only way + + + align:start position:0% +that that's guaranteed and the only way +you can prove that it's guaranteed to be + + align:start position:0% +you can prove that it's guaranteed to be + + + align:start position:0% +you can prove that it's guaranteed to be +possible to do this is from What's + + align:start position:0% +possible to do this is from What's + + + align:start position:0% +possible to do this is from What's +called the Great orthogonality theorem + + align:start position:0% +called the Great orthogonality theorem + + + align:start position:0% +called the Great orthogonality theorem +but it is possible to find a + + align:start position:0% +but it is possible to find a + + + align:start position:0% +but it is possible to find a +transformation that block diagonalizes + + align:start position:0% +transformation that block diagonalizes + + + align:start position:0% +transformation that block diagonalizes +all of these + + align:start position:0% +all of these + + + align:start position:0% +all of these +matrices in the same into submatrices of + + align:start position:0% +matrices in the same into submatrices of + + + align:start position:0% +matrices in the same into submatrices of +the same + + align:start position:0% +the same + + + align:start position:0% +the same +Dimension and then we can write the + + align:start position:0% +Dimension and then we can write the + + + align:start position:0% +Dimension and then we can write the +reducible + + align:start position:0% +reducible + + + align:start position:0% +reducible +uh representation that we can generate + + align:start position:0% +uh representation that we can generate + + + align:start position:0% +uh representation that we can generate +very easily by simple it's hardly + + align:start position:0% +very easily by simple it's hardly + + + align:start position:0% +very easily by simple it's hardly +even it's + + align:start position:0% +even it's + + + align:start position:0% +even it's +it's it's magic you you generate this + + align:start position:0% +it's it's magic you you generate this + + + align:start position:0% +it's it's magic you you generate this +thing and then you can uh say that the + + align:start position:0% +thing and then you can uh say that the + + + align:start position:0% +thing and then you can uh say that the +Matrix Matrix is the sum of these + + align:start position:0% +Matrix Matrix is the sum of these + + + align:start position:0% +Matrix Matrix is the sum of these +individual matrices arranged along the + + align:start position:0% +individual matrices arranged along the + + + align:start position:0% +individual matrices arranged along the +diagonal + + align:start position:0% +diagonal + + + align:start position:0% +diagonal +so we should be able to write this + + align:start position:0% +so we should be able to write this + + + align:start position:0% +so we should be able to write this +reducible uh representation as a number + + align:start position:0% +reducible uh representation as a number + + + align:start position:0% +reducible uh representation as a number +how many + + align:start position:0% +how many + + + align:start position:0% +how many +times the + + align:start position:0% +times the + + + align:start position:0% +times the +new irreducible representation appears + + align:start position:0% +new irreducible representation appears + + + align:start position:0% +new irreducible representation appears +in + + align:start position:0% +in + + + align:start position:0% +in +it that so we should be able to + + align:start position:0% +it that so we should be able to + + + align:start position:0% +it that so we should be able to +decompose every reducible representation + + align:start position:0% +decompose every reducible representation + + + align:start position:0% +decompose every reducible representation +into the irreducible representations + + align:start position:0% +into the irreducible representations + + + align:start position:0% +into the irreducible representations +that it's made up out + + align:start position:0% + + + + align:start position:0% + +of okay now the Great orthogonal theorem + + align:start position:0% +of okay now the Great orthogonal theorem + + + align:start position:0% +of okay now the Great orthogonal theorem +tells us how to do this and why we can + + align:start position:0% +tells us how to do this and why we can + + + align:start position:0% +tells us how to do this and why we can +do this and all that wonderful stuff and + + align:start position:0% +do this and all that wonderful stuff and + + + align:start position:0% +do this and all that wonderful stuff and +I'll write it down but we don't use it + + align:start position:0% +I'll write it down but we don't use it + + + align:start position:0% +I'll write it down but we don't use it +we use the reduced form of it which is + + align:start position:0% +we use the reduced form of it which is + + + align:start position:0% +we use the reduced form of it which is +much simpler and easier to remember so + + align:start position:0% +much simpler and easier to remember so + + + align:start position:0% +much simpler and easier to remember so +the great orthogonal theorem from which + + align:start position:0% +the great orthogonal theorem from which + + + align:start position:0% +the great orthogonal theorem from which +all of these group theoretical results + + align:start position:0% +all of these group theoretical results + + + align:start position:0% +all of these group theoretical results +can be derived and which can be proven + + align:start position:0% +can be derived and which can be proven + + + align:start position:0% +can be derived and which can be proven +but in a fairly tedious way uh so this + + align:start position:0% +but in a fairly tedious way uh so this + + + align:start position:0% +but in a fairly tedious way uh so this +is the sum over symmetry + + align:start position:0% +is the sum over symmetry + + + align:start position:0% +is the sum over symmetry +operations and uh so we have now the + + align:start position:0% + + + + align:start position:0% + +uh so this is a particular irreducible + + align:start position:0% +uh so this is a particular irreducible + + + align:start position:0% +uh so this is a particular irreducible +representation these are the I and K row + + align:start position:0% +representation these are the I and K row + + + align:start position:0% +representation these are the I and K row +and column of that + + align:start position:0% +and column of that + + + align:start position:0% +and column of that +Matrix and then we have another + + align:start position:0% +Matrix and then we have another + + + align:start position:0% +Matrix and then we have another +uh irreducible + + align:start position:0% +uh irreducible + + + align:start position:0% +uh irreducible +representation and we have J and M and R + + align:start position:0% +representation and we have J and M and R + + + align:start position:0% +representation and we have J and M and R +same R complex + + align:start position:0% +same R complex + + + align:start position:0% +same R complex +conjugate so here are + + align:start position:0% +conjugate so here are + + + align:start position:0% +conjugate so here are +two uh sets of Matrix elements the great + + align:start position:0% +two uh sets of Matrix elements the great + + + align:start position:0% +two uh sets of Matrix elements the great +orthogonality theorem tells you that + + align:start position:0% +orthogonality theorem tells you that + + + align:start position:0% +orthogonality theorem tells you that +this product is + + align:start position:0% +this product is + + + align:start position:0% +this product is +G + + align:start position:0% +G + + + align:start position:0% +G +the + + align:start position:0% +the + + + align:start position:0% +the +order of the + + align:start position:0% +order of the + + + align:start position:0% +order of the +group and which is the number of + + align:start position:0% +group and which is the number of + + + align:start position:0% +group and which is the number of +symmetry + + align:start position:0% + + + + align:start position:0% + +elements um and divided by n mu the + + align:start position:0% +elements um and divided by n mu the + + + align:start position:0% +elements um and divided by n mu the +dimension of the Muth irreducible + + align:start position:0% +dimension of the Muth irreducible + + + align:start position:0% +dimension of the Muth irreducible +representation and then + + align:start position:0% +representation and then + + + align:start position:0% +representation and then +Delta uh mu new Delta i j Delta k m + + align:start position:0% + + + + align:start position:0% + +so it says if you uh if you have two + + align:start position:0% +so it says if you uh if you have two + + + align:start position:0% +so it says if you uh if you have two +different irreducible + + align:start position:0% +different irreducible + + + align:start position:0% +different irreducible +representations they're orthogonal in + + align:start position:0% +representations they're orthogonal in + + + align:start position:0% +representations they're orthogonal in +the sense of all the rows and all the + + align:start position:0% +the sense of all the rows and all the + + + align:start position:0% +the sense of all the rows and all the +columns and so we have all of this you + + align:start position:0% +columns and so we have all of this you + + + align:start position:0% +columns and so we have all of this you +know all of these orthogonalities in + + align:start position:0% +know all of these orthogonalities in + + + align:start position:0% +know all of these orthogonalities in +this little thing here um + + align:start position:0% + + + + align:start position:0% + +okay it's possible to prove that n new + + align:start position:0% +okay it's possible to prove that n new + + + align:start position:0% +okay it's possible to prove that n new +squar + + align:start position:0% +squar + + + align:start position:0% +squar +is equal to G where this + + align:start position:0% +is equal to G where this + + + align:start position:0% +is equal to G where this +is these this is the dimension of each + + align:start position:0% +is these this is the dimension of each + + + align:start position:0% +is these this is the dimension of each +of this is the dimension of the N + + align:start position:0% +of this is the dimension of the N + + + align:start position:0% +of this is the dimension of the N +irreducible representation there's a + + align:start position:0% +irreducible representation there's a + + + align:start position:0% +irreducible representation there's a +certain number of irreducible + + align:start position:0% +certain number of irreducible + + + align:start position:0% +certain number of irreducible +representations you sum all the orders + + align:start position:0% +representations you sum all the orders + + + align:start position:0% +representations you sum all the orders +of all of them and you get + + align:start position:0% + + + + align:start position:0% + +G this great orthogonality theorem can + + align:start position:0% +G this great orthogonality theorem can + + + align:start position:0% +G this great orthogonality theorem can +be simplified by simply taking the sum + + align:start position:0% +be simplified by simply taking the sum + + + align:start position:0% +be simplified by simply taking the sum +over uh uh + + align:start position:0% + + + + align:start position:0% + +the the diagonal elements and so we can + + align:start position:0% +the the diagonal elements and so we can + + + align:start position:0% +the the diagonal elements and so we can +write this reduced form uh of well let's + + align:start position:0% +write this reduced form uh of well let's + + + align:start position:0% +write this reduced form uh of well let's +just + + align:start position:0% + + + + align:start position:0% + +uh so the + + align:start position:0% +uh so the + + + align:start position:0% +uh so the +character of the Muth + + align:start position:0% +character of the Muth + + + align:start position:0% +character of the Muth +representation is just given by the sum + + align:start position:0% +representation is just given by the sum + + + align:start position:0% +representation is just given by the sum +over + + align:start position:0% +over + + + align:start position:0% +over +i d mu I I of + + align:start position:0% +i d mu I I of + + + align:start position:0% +i d mu I I of +R so that's just the sum of the diagonal + + align:start position:0% +R so that's just the sum of the diagonal + + + align:start position:0% +R so that's just the sum of the diagonal +elements and the reduced form of the + + align:start position:0% +elements and the reduced form of the + + + align:start position:0% +elements and the reduced form of the +great orthogonality theorem is sum over + + align:start position:0% +great orthogonality theorem is sum over + + + align:start position:0% +great orthogonality theorem is sum over +symmetry + + align:start position:0% +symmetry + + + align:start position:0% +symmetry +elements Kai mu + + align:start position:0% + + + + align:start position:0% + +R + + align:start position:0% +R + + + align:start position:0% +R +Kai + + align:start position:0% +Kai + + + align:start position:0% +Kai +new are + + align:start position:0% + + + + align:start position:0% + +star is equal to + + align:start position:0% +star is equal to + + + align:start position:0% +star is equal to +G time Delta Mu + + align:start position:0% +G time Delta Mu + + + align:start position:0% +G time Delta Mu +new so these + + align:start position:0% +new so these + + + align:start position:0% +new so these +characters are sort of a generalization + + align:start position:0% +characters are sort of a generalization + + + align:start position:0% +characters are sort of a generalization +of vectors these characters are + + align:start position:0% + + + + align:start position:0% + +orthogonal because of that and uh when + + align:start position:0% +orthogonal because of that and uh when + + + align:start position:0% +orthogonal because of that and uh when +you when you sum over the Symmetry + + align:start position:0% +you when you sum over the Symmetry + + + align:start position:0% +you when you sum over the Symmetry +elements you get G + + align:start position:0% +elements you get G + + + align:start position:0% +elements you get G +and so this is the thing one uses and it + + align:start position:0% +and so this is the thing one uses and it + + + align:start position:0% +and so this is the thing one uses and it +provides a basis for calculating the uh + + align:start position:0% +provides a basis for calculating the uh + + + align:start position:0% +provides a basis for calculating the uh +decomposition of a reducible + + align:start position:0% +decomposition of a reducible + + + align:start position:0% +decomposition of a reducible +representation into its irreducible + + align:start position:0% +representation into its irreducible + + + align:start position:0% +representation into its irreducible +representations + + align:start position:0% +representations + + + align:start position:0% +representations +so I'm just stating these results + + align:start position:0% +so I'm just stating these results + + + align:start position:0% +so I'm just stating these results +because you could spend weeks deriving + + align:start position:0% +because you could spend weeks deriving + + + align:start position:0% +because you could spend weeks deriving +them but the neat thing is applying them + + align:start position:0% +them but the neat thing is applying them + + + align:start position:0% +them but the neat thing is applying them +what time is it + + align:start position:0% +what time is it + + + align:start position:0% +what time is it +okay and + + align:start position:0% +okay and + + + align:start position:0% +okay and +so the way you apply them + + align:start position:0% +so the way you apply them + + + align:start position:0% +so the way you apply them +is uh we would like to know how many + + align:start position:0% +is uh we would like to know how many + + + align:start position:0% +is uh we would like to know how many +times each irreducible representation + + align:start position:0% + + + + align:start position:0% + +appears in a reducible representation + + align:start position:0% +appears in a reducible representation + + + align:start position:0% +appears in a reducible representation +and so we have a new sum over new Kai + + align:start position:0% +and so we have a new sum over new Kai + + + align:start position:0% +and so we have a new sum over new Kai +new + + align:start position:0% +new + + + align:start position:0% +new +R so + + align:start position:0% +R so + + + align:start position:0% +R so +we want to know what these the the + + align:start position:0% +we want to know what these the the + + + align:start position:0% +we want to know what these the the +number of times each irreducible + + align:start position:0% +number of times each irreducible + + + align:start position:0% +number of times each irreducible +representation appears in a reducible + + align:start position:0% +representation appears in a reducible + + + align:start position:0% +representation appears in a reducible +representation and that's given through + + align:start position:0% +representation and that's given through + + + align:start position:0% +representation and that's given through +the + + align:start position:0% +the + + + align:start position:0% +the +um the great orthogonality theorem for + + align:start position:0% +um the great orthogonality theorem for + + + align:start position:0% +um the great orthogonality theorem for +characters as 1 / G and this is the + + align:start position:0% +characters as 1 / G and this is the + + + align:start position:0% +characters as 1 / G and this is the +equation you'll always be + + align:start position:0% +equation you'll always be + + + align:start position:0% +equation you'll always be +using + + align:start position:0% +using + + + align:start position:0% +using +R kind + + align:start position:0% + + + + align:start position:0% + +reducible + + align:start position:0% +reducible + + + align:start position:0% +reducible +K + + align:start position:0% +K + + + align:start position:0% +K +new + + align:start position:0% + + + + align:start position:0% + +star so you have an + + align:start position:0% +star so you have an + + + align:start position:0% +star so you have an +element you + + align:start position:0% +element you + + + align:start position:0% +element you +have for a reducible representation it's + + align:start position:0% +have for a reducible representation it's + + + align:start position:0% +have for a reducible representation it's +it's going to be a set of + + align:start position:0% + + + + align:start position:0% + +numbers what am I going to how am I + + align:start position:0% +numbers what am I going to how am I + + + align:start position:0% +numbers what am I going to how am I +going to call them number number + + align:start position:0% + + + + align:start position:0% + +number corresponding to R1 + + align:start position:0% +number corresponding to R1 + + + align:start position:0% +number corresponding to R1 +R2 + + align:start position:0% +R2 + + + align:start position:0% +R2 +Etc and so + + align:start position:0% +Etc and so + + + align:start position:0% +Etc and so +both the reducible representation and + + align:start position:0% +both the reducible representation and + + + align:start position:0% +both the reducible representation and +the irreducible representation is the + + align:start position:0% +the irreducible representation is the + + + align:start position:0% +the irreducible representation is the +same number of numbers so you just take + + align:start position:0% +same number of numbers so you just take + + + align:start position:0% +same number of numbers so you just take +these vectors and multiply them and + + align:start position:0% +these vectors and multiply them and + + + align:start position:0% +these vectors and multiply them and +divide by the order of the group and you + + align:start position:0% +divide by the order of the group and you + + + align:start position:0% +divide by the order of the group and you +get the number of times a particular + + align:start position:0% +get the number of times a particular + + + align:start position:0% +get the number of times a particular +irreducible representation appears in a + + align:start position:0% +irreducible representation appears in a + + + align:start position:0% +irreducible representation appears in a +reducible representation there's extra + + align:start position:0% +reducible representation there's extra + + + align:start position:0% +reducible representation there's extra +simplification and we + + align:start position:0% +simplification and we + + + align:start position:0% +simplification and we +have you don't need this but since the + + align:start position:0% +have you don't need this but since the + + + align:start position:0% +have you don't need this but since the +character tables are always arranged in + + align:start position:0% +character tables are always arranged in + + + align:start position:0% +character tables are always arranged in +this way we have the + + align:start position:0% +this way we have the + + + align:start position:0% +this way we have the +operations the Symmetry operations can + + align:start position:0% +operations the Symmetry operations can + + + align:start position:0% +operations the Symmetry operations can +be divided into classes how do we know a + + align:start position:0% +be divided into classes how do we know a + + + align:start position:0% +be divided into classes how do we know a +class well what we do is we say okay + + align:start position:0% +class well what we do is we say okay + + + align:start position:0% +class well what we do is we say okay +here is a symmetry + + align:start position:0% +here is a symmetry + + + align:start position:0% +here is a symmetry +operation Let's + + align:start position:0% + + + + align:start position:0% + +uh oops calculate for all possible + + align:start position:0% +uh oops calculate for all possible + + + align:start position:0% +uh oops calculate for all possible +symmetry elements in the group this + + align:start position:0% +symmetry elements in the group this + + + align:start position:0% +symmetry elements in the group this +transformation and what this will yield + + align:start position:0% +transformation and what this will yield + + + align:start position:0% +transformation and what this will yield +will be all of the members of the class + + align:start position:0% +will be all of the members of the class + + + align:start position:0% +will be all of the members of the class +that contains this + + align:start position:0% +that contains this + + + align:start position:0% +that contains this +guy and so when you see for + + align:start position:0% +guy and so when you see for + + + align:start position:0% +guy and so when you see for +example uh the point group for c3v the + + align:start position:0% +example uh the point group for c3v the + + + align:start position:0% +example uh the point group for c3v the +uh the group that uh is ammonia you + + align:start position:0% +uh the group that uh is ammonia you + + + align:start position:0% +uh the group that uh is ammonia you +see e 2 + + align:start position:0% +see e 2 + + + align:start position:0% +see e 2 +C3 3 Sigma + + align:start position:0% + + + + align:start position:0% + +V and then you see A1 A2 and + + align:start position:0% + + + + align:start position:0% + +E and so there is the identity operation + + align:start position:0% +E and so there is the identity operation + + + align:start position:0% +E and so there is the identity operation +it's in a class by itself there are two + + align:start position:0% +it's in a class by itself there are two + + + align:start position:0% +it's in a class by itself there are two +c3s + + align:start position:0% +c3s + + + align:start position:0% +c3s +C3 uh and uh C3 and C3 squ or C3 and C3 + + align:start position:0% +C3 uh and uh C3 and C3 squ or C3 and C3 + + + align:start position:0% +C3 uh and uh C3 and C3 squ or C3 and C3 +inverse there are three sigma + + align:start position:0% +inverse there are three sigma + + + align:start position:0% +inverse there are three sigma +vs and and so there's a class of + + align:start position:0% +vs and and so there's a class of + + + align:start position:0% +vs and and so there's a class of +Dimension one class of Dimension two + + align:start position:0% +Dimension one class of Dimension two + + + align:start position:0% +Dimension one class of Dimension two +class of Dimension + + align:start position:0% +class of Dimension + + + align:start position:0% +class of Dimension +three and when you do that you discover + + align:start position:0% +three and when you do that you discover + + + align:start position:0% +three and when you do that you discover +that the character table is square + + align:start position:0% +that the character table is square + + + align:start position:0% +that the character table is square +because the same number of class there + + align:start position:0% +because the same number of class there + + + align:start position:0% +because the same number of class there +are the same number of irreducible + + align:start position:0% +are the same number of irreducible + + + align:start position:0% +are the same number of irreducible +representation as there are number of + + align:start position:0% +representation as there are number of + + + align:start position:0% +representation as there are number of +classes and that's + + align:start position:0% +classes and that's + + + align:start position:0% +classes and that's +wonderful and so then + + align:start position:0% +wonderful and so then + + + align:start position:0% +wonderful and so then +uh in this character table you you have + + align:start position:0% +uh in this character table you you have + + + align:start position:0% +uh in this character table you you have +the characters for each of + + align:start position:0% +the characters for each of + + + align:start position:0% +the characters for each of +these and so this is the totally + + align:start position:0% +these and so this is the totally + + + align:start position:0% +these and so this is the totally +symmetric representation nothing happens + + align:start position:0% +symmetric representation nothing happens + + + align:start position:0% +symmetric representation nothing happens +since you just get + + align:start position:0% +since you just get + + + align:start position:0% +since you just get +ones and uh + + align:start position:0% +ones and uh + + + align:start position:0% +ones and uh +um and + + align:start position:0% +um and + + + align:start position:0% +um and +for uh A2 uh + + align:start position:0% +for uh A2 uh + + + align:start position:0% +for uh A2 uh +A2 uh + + align:start position:0% +A2 uh + + + align:start position:0% +A2 uh +is odd with respect to reflection planes + + align:start position:0% +is odd with respect to reflection planes + + + align:start position:0% +is odd with respect to reflection planes +and uh even with respect to uh uh + + align:start position:0% +and uh even with respect to uh uh + + + align:start position:0% +and uh even with respect to uh uh +rotation and he has this + + align:start position:0% +rotation and he has this + + + align:start position:0% +rotation and he has this +form and there's there's some rules + + align:start position:0% +form and there's there's some rules + + + align:start position:0% +form and there's there's some rules +about this but okay so this is the + + align:start position:0% +about this but okay so this is the + + + align:start position:0% +about this but okay so this is the +character table you have a set of + + align:start position:0% +character table you have a set of + + + align:start position:0% +character table you have a set of +numbers that you + + align:start position:0% +numbers that you + + + align:start position:0% +numbers that you +generate by say having a 3n dimensional + + align:start position:0% +generate by say having a 3n dimensional + + + align:start position:0% +generate by say having a 3n dimensional +representation uh and so we get a + + align:start position:0% +representation uh and so we get a + + + align:start position:0% +representation uh and so we get a +reducible represent and then we ask how + + align:start position:0% +reducible represent and then we ask how + + + align:start position:0% +reducible represent and then we ask how +many times does A1 appear in it how many + + align:start position:0% +many times does A1 appear in it how many + + + align:start position:0% +many times does A1 appear in it how many +times is A2 how many times is e appear + + align:start position:0% +times is A2 how many times is e appear + + + align:start position:0% +times is A2 how many times is e appear +in + + align:start position:0% +in + + + align:start position:0% +in +it and it's really mechanical and simple + + align:start position:0% +it and it's really mechanical and simple + + + align:start position:0% +it and it's really mechanical and simple +and the key is not screwing up uh + + align:start position:0% +and the key is not screwing up uh + + + align:start position:0% +and the key is not screwing up uh +because this looks like a product + + align:start position:0% +because this looks like a product + + + align:start position:0% +because this looks like a product +of um the an element and the character + + align:start position:0% +of um the an element and the character + + + align:start position:0% +of um the an element and the character +of the reducible representation and one + + align:start position:0% +of the reducible representation and one + + + align:start position:0% +of the reducible representation and one +goes by classes so you have to multiply + + align:start position:0% +goes by classes so you have to multiply + + + align:start position:0% +goes by classes so you have to multiply +if you're going to sum over classes ra + + align:start position:0% +if you're going to sum over classes ra + + + align:start position:0% +if you're going to sum over classes ra +rather than over the Symmetry operations + + align:start position:0% +rather than over the Symmetry operations + + + align:start position:0% +rather than over the Symmetry operations +you have to remember to multiply by + + align:start position:0% +you have to remember to multiply by + + + align:start position:0% +you have to remember to multiply by +these things 90% of the errors that I've + + align:start position:0% +these things 90% of the errors that I've + + + align:start position:0% +these things 90% of the errors that I've +made in applying group theory has been + + align:start position:0% +made in applying group theory has been + + + align:start position:0% +made in applying group theory has been +forgetting to multiply by the order of + + align:start position:0% +forgetting to multiply by the order of + + + align:start position:0% +forgetting to multiply by the order of +the class the number yes the order of + + align:start position:0% +the class the number yes the order of + + + align:start position:0% +the class the number yes the order of +the classes + + align:start position:0% +the classes + + + align:start position:0% +the classes +and so you get you know it works out + + align:start position:0% +and so you get you know it works out + + + align:start position:0% +and so you get you know it works out +sort of pretty well and all of a sudden + + align:start position:0% +sort of pretty well and all of a sudden + + + align:start position:0% +sort of pretty well and all of a sudden +you get some representation appearing + + align:start position:0% +you get some representation appearing + + + align:start position:0% +you get some representation appearing +three and a half times or you come up + + align:start position:0% +three and a half times or you come up + + + align:start position:0% +three and a half times or you come up +short and that is the error you're going + + align:start position:0% +short and that is the error you're going + + + align:start position:0% +short and that is the error you're going +to + + align:start position:0% +to + + + align:start position:0% +to +make okay so I've more or less touched + + align:start position:0% +make okay so I've more or less touched + + + align:start position:0% +make okay so I've more or less touched +on the high points of what I've included + + align:start position:0% +on the high points of what I've included + + + align:start position:0% +on the high points of what I've included +in these notes I do think that it would + + align:start position:0% +in these notes I do think that it would + + + align:start position:0% +in these notes I do think that it would +be useful to play around I'm not going + + align:start position:0% +be useful to play around I'm not going + + + align:start position:0% +be useful to play around I'm not going +to make an assignment but I I recommend + + align:start position:0% +to make an assignment but I I recommend + + + align:start position:0% +to make an assignment but I I recommend +picking a molecule that has uh well + + align:start position:0% +picking a molecule that has uh well + + + align:start position:0% +picking a molecule that has uh well +Benzene is too simple because the + + align:start position:0% +Benzene is too simple because the + + + align:start position:0% +Benzene is too simple because the +carbons and the hydrogens more or less + + align:start position:0% +carbons and the hydrogens more or less + + + align:start position:0% +carbons and the hydrogens more or less +do the same thing there are certainly + + align:start position:0% +do the same thing there are certainly + + + align:start position:0% +do the same thing there are certainly +interesting things but uh you ought to + + align:start position:0% +interesting things but uh you ought to + + + align:start position:0% +interesting things but uh you ought to +pick a molecule that has a relatively + + align:start position:0% +pick a molecule that has a relatively + + + align:start position:0% +pick a molecule that has a relatively +High symmetry but where there's there + + align:start position:0% +High symmetry but where there's there + + + align:start position:0% +High symmetry but where there's there +there's some interesting differences I + + align:start position:0% +there's some interesting differences I + + + align:start position:0% +there's some interesting differences I +can't think of something + + align:start position:0% +can't think of something + + + align:start position:0% +can't think of something +offhand uh but uh I suspect that uh um + + align:start position:0% +offhand uh but uh I suspect that uh um + + + align:start position:0% +offhand uh but uh I suspect that uh um +the the uh uh + + align:start position:0% +the the uh uh + + + align:start position:0% +the the uh uh +cyclohexane uh where you have boat and + + align:start position:0% +cyclohexane uh where you have boat and + + + align:start position:0% +cyclohexane uh where you have boat and +chair forms and so let's say take the + + align:start position:0% +chair forms and so let's say take the + + + align:start position:0% +chair forms and so let's say take the +chair form of cyclohexane and classify + + align:start position:0% +chair form of cyclohexane and classify + + + align:start position:0% +chair form of cyclohexane and classify +it um that's a relatively low Order + + align:start position:0% +it um that's a relatively low Order + + + align:start position:0% +it um that's a relatively low Order +Group um but whatever you do I would + + align:start position:0% +Group um but whatever you do I would + + + align:start position:0% +Group um but whatever you do I would +recommend using various cartoons to + + align:start position:0% +recommend using various cartoons to + + + align:start position:0% +recommend using various cartoons to +descri you know to pick out the kinds of + + align:start position:0% +descri you know to pick out the kinds of + + + align:start position:0% +descri you know to pick out the kinds of +motions that a mole you can have and + + align:start position:0% +motions that a mole you can have and + + + align:start position:0% +motions that a mole you can have and +you'll be able to classify all of the + + align:start position:0% +you'll be able to classify all of the + + + align:start position:0% +you'll be able to classify all of the +vibrations and there'll be certain + + align:start position:0% +vibrations and there'll be certain + + + align:start position:0% +vibrations and there'll be certain +irreducible representations that have + + align:start position:0% +irreducible representations that have + + + align:start position:0% +irreducible representations that have +are pure bending and others that are + + align:start position:0% +are pure bending and others that are + + + align:start position:0% +are pure bending and others that are +pure planer stretching or you know there + + align:start position:0% +pure planer stretching or you know there + + + align:start position:0% +pure planer stretching or you know there +will be certain motions that you can + + align:start position:0% +will be certain motions that you can + + + align:start position:0% +will be certain motions that you can +name simply by doing group Theory and I + + align:start position:0% +name simply by doing group Theory and I + + + align:start position:0% +name simply by doing group Theory and I +don't know if cyclohexane is a good + + align:start position:0% +don't know if cyclohexane is a good + + + align:start position:0% +don't know if cyclohexane is a good +choice but I cannot think off the top of + + align:start position:0% +choice but I cannot think off the top of + + + align:start position:0% +choice but I cannot think off the top of +my head of a good molecule that's that's + + align:start position:0% +my head of a good molecule that's that's + + + align:start position:0% +my head of a good molecule that's that's +that's not trivial but laborious like + + align:start position:0% +that's not trivial but laborious like + + + align:start position:0% +that's not trivial but laborious like +Benzene or trivial and not laborious + + align:start position:0% +Benzene or trivial and not laborious + + + align:start position:0% +Benzene or trivial and not laborious +like form Malahide somewhere in between + + align:start position:0% +like form Malahide somewhere in between + + + align:start position:0% +like form Malahide somewhere in between +there's something really + + align:start position:0% +there's something really + + + align:start position:0% +there's something really +useful and so anyway uh I will continue + + align:start position:0% +useful and so anyway uh I will continue + + + align:start position:0% +useful and so anyway uh I will continue +with this on Wednesday \ No newline at end of file diff --git a/PVv4ST8NZaA.txt b/PVv4ST8NZaA.txt new file mode 100644 index 0000000000000000000000000000000000000000..bc9366bb33489e02f34c295d513e50b20874c2a3 --- /dev/null +++ b/PVv4ST8NZaA.txt @@ -0,0 +1,1173 @@ +I want to go back a second to the end of last time because in the + +closing moments there, we, or at least I, got a little bit + + lost, and where the plusses and + +minuses were at a certain table. + +And, I want to go back and make sure we've got that straight. + +We were talking about a situation where we were trying to use genetics, + +and the phenotypes that might be observed in mutants to try to + +understand the biochemical pathway because we're beginning to try to + +unite the geneticist's point of view who looks only at mutants, + +and the biochemist's point of view who looks at pathways and proteins. + +And, I had hypothesized that there was some biochemists who had thought + +up a possible pathway for the synthesis of arginine that involved + +some precursor, alpha, beta, gamma, + +where alpha is turned into beta; beta is turned into gamma; and gamma + +is used to turn into arginine. And, hypothetically, + +there would be some enzymes: enzyme A that converts alpha, + +enzyme B that converts beta, and enzyme C that converts gamma. + +And, we were just thinking about, what would the phenotypes look like + +of different arginine auxotrophs that had blocks at different stages + +in the pathway. If I had an arginine auxotroph that + +had a block here because let's say a mutation in a gene affecting this + +enzyme, or at a block here at a mutation affecting, say, + +the gene that encodes enzyme C, how would I be able to tell very + +simply that they were in different genes? Last time, + +we found that we could tell they were in different genes by doing a + +cross between a mutant that had the first mutation, + +and a mutant that had the second mutation, and looking at the double + +heterozygote, right? And, if in the double heterozygote + +you had a wild type or a normal phenotype, then they had to be in + +different genes, OK? Remember that? + +That was called a test of complementation. + +That was how we were able to sort out which mutations were in the same + +gene, and which mutations were in different genes. + +Now we can go a step further. When we've established that they're + +in different genes, we can try to begin to think, + +how do these genes relate to a biochemical pathway? + +I wanted to begin to introduce, because it'll be relevant for today, + +this notion: so, suppose I had a mutation that affected enzyme A so + +that this enzymatic step couldn't be carried out. + +Such a mutant, when I just try to grow it on + +minimal medium won't be able to grow. If I give it the substrate alpha, + +it doesn't do it any good because it hasn't got the enzyme to convert + +alpha. So, given alpha, it won't grow. But if I give it + +beta, what will happen? It can grow because I've bypassed + +the defect. What about if I give it gamma? Arginine? + +Now, if instead the mutation were affecting enzymatic step here, + +then if I give it on minimal or medium + +but it can grow on gamma. What about this last line? + +If I have a mutation and the last enzymatic step, + +minimal medium can't grow with alpha, can't grow with beta, + +can't even grow with gamma. But, it can grow with arginine + +because I've bypassed that step. So, I get a different phenotype, + +the inability to grow even on gamma, + +but I can grow on arginine. Now, here, if I put together those + +mutants and make a double mutant, a double homozygote, let's say, + +that's defective in both A and B, which will it look like? Will it be + +able to grow on minimal medium? Will it be able to grow on alpha? + +Will it be able to grow on beta? + +Will it be able to grow on gamma and arginine? What about if I have a + +double mutant in B and C, minus, minus, minus, minus, + +plus? So this looks the same as that. This looks the same as that. + +And so, by looking at different mutant combinations, + +I can see that the phenotype of B here is what occurs in the double + +mutant. So, this phenotype is epistatic to this phenotype. + +Epistatic means stands upon, OK? So, phenotypes, just like + +phenotypes can be recessive or dominant, you can also speak about + +them being epistatic. And epistatic means when you have + +both of two mutations together at the epistatic + +then one of them is epistatic to the other, perhaps. + +It will, in fact, be the one that is present. + +So, this is not so easy to do in many cases because if I take + +different kinds of mutation affecting wing development, + +and I put them together in the same fly, I may just get a very messed up + +wing, and it's very hard to tell that the double mutant has a + +phenotype that looks like either of the two single mutants. + +But sometimes, if they fall very nicely in a pathway where this + +affects the first step, this affects the second step + +this affects the third step, this affects the fourth step, + +then the double mutant will look like one of those, + +OK? And, that way you can somehow order things in a biochemical + +pathway. Now, notice, this is all indirect, + +right? This is what geneticists did in the middle of the 20th century to + +try to figure out how to connect up mutants to biochemistry. + +Actually, that's not true. It's what geneticists still do + +today because you might think that Well, we don't need to do this + +anymore, but in fact geneticists constantly are looking at mutants + +and making connections trying to say, what does this double combination + +look like? What does that double combination look like, + +and how does that tell us about the developmental pathway, + +which cell signals which cell? This turns out to be one of the + +most powerful ways to figure out what mutations do by saying the + +combination of two mutations looks like the same as one of them, + +allowing you to order the mutations in a pathway. + +And, there's no general way to grind up a cell and order things in a + +pathway. Genetics is a very powerful tool for doing that. + +Now, there are some ways to grind up cells and order things, + +but you need both of these techniques to believe stuff. + +Anyway, I wanted to go over that, because it is an important concept, + +the concept of epistasis, the concept of relating mutations to + +steps and pathways, but what I mostly want to do today + +is go on now to talk about genetics not in organisms like yeast or fruit + +flies or even peas, but genetics in humans. + +So, what's different about genetics in humans than genetics in yeast? + +You can't choose who mates with whom. Well, you can. + +I mean, in the days of arranged marriages maybe you couldn't, + +but you can choose who mates with whom, but only for yourself, + +right? What you can't do is arrange other crosses in the human + +population as an experimentalist. Now, your own choice of mating, + +unfortunately or fortunately perhaps produces too few progeny to be + +statistically significant. As a parent of three, I think about + +what it would take to raise a statistically significant number of + +offspring to draw any conclusions, and I don't think I could do that. + +So, you're absolutely right. We can't arrange the matings that + +we want in the human population. So, that's the big difference. + +So, can we do genetics anyway? How do we do genetics even though + +we can't arrange the matings the way we'd like to? Sorry? + +Well, family trees. We have to take the matings as we find them in + +the human population. You can talk to somebody who might + +have an interesting phenotype, I don't know, attached earlobes, + +or very early heart disease, or some unusual color of eyes, + +and begin to collect a family history on that person. + +It's a little bit of a dodgy thing because you might just be relying on + +that person's recollection. So, if you were really industrious + +about this, you'd go check out each of their family members and test for + +yourself whether they have the phenotype. People who do serious + +human genetic studies often go and do that. They have to go confirm, + +either by getting hospital records or interviewing the other members of + +the family, etc. So, this is not as easy as plating + +out lots of yeasts on a Petri plate. + +And then you get pedigrees. And the pedigrees look like this. + +Here's a pedigree. Tell me what you make of it. + +Now, symbols: squares are males, circles are females by convention, + +a colored in symbol means the phenotype that we're + +interested in studying at the moment. So, in any given problem, + +somebody will tell you, well, we're studying some interesting + +phenotype. You often have an index case or a proband, + +meaning the person who comes to clinical attention, + +and then you chase back in the pedigree and try to reconstruct. + +So, suppose I saw a pedigree like this. + +What conclusions could I draw? Sorry? Recessive, sex link trait; + +why sex link trait? So, let's see if we can get your + +model up here. You think that this represents + +sex-linked inheritance. So, what would the genotype be of + +this male here? Mutant: I'll use M to denote a + +mutant carried on the X chromosome, and a Y on the opposite chromosome. + +What's the genotype of the female here? + +So, it's plus over plus where I'll use plus to denote the gene carried + +on the normal X chromosome. OK, and then what do you think + +happened over here? So, mutant over plus, + +you mate to this male who is plus over plus. Why is that male plus + +over plus? Oh, right, good point. + +It's not plus over plus. It's plus over Y. Why is that male + +plus over Y as opposed to mutant over Y? + +He'd have the mutant phenotype. So, he doesn't have the mutant + +phenotype so he can infer he's plus over Y. OK, and then what happens + +here? Mutant over Y; this is plus over Y. How did this person get + +plus over Y? They just the plus for mom, and the daughters, + +Y from dad, and a plus from mom. That's cool. Now, what about the + +daughters there? They're plus over plus, + +or M over plus? Is one, one, and one the other? Well, + +in textbooks it's always plus over plus and M over plus, + +but in real life? We don't know, right? So, this could be plus over + +plus, or M over plus, we don't know, OK? Now, + +what about on this side of the pedigree here? + +What's the genotype here? Plus over Y, OK. + +Why not mutant over Y? Because if they got the mutant, + +it would have to come from the, OK, so here, plus over plus, and then + +here, everybody is normal because there's no mutant allele segregated. + +Yes? Yeah, couldn't there just be recessive? I mean, + +it's a nice story about the sex link + +but couldn't it be recessive? So, walk me through it being + +recessive. M over plus, plus over plus. Wait, wait, + +wait, hang on. Could this be M over plus, and that person be affected? + +It's got to be M over M, right so mutants over mutants + +but that's possible. Yeah, OK. So, what would this + +person be? Plus over plus, let's say, come over here. Now, + +what would this person be? M plus. It has to be M plus because, OK, + +and what about this person here? M plus, now what about the + +offspring? So, one of them is M over M, + +plus over plus, and two M pluses. Does it always work out like that? + +[LAUGHTER] No, it doesn't always work out like that at all. + +So, I'm just going to write plus over plus here just to say, + +tough, right? In real life, it doesn't always come out like that. + +What about over here? It would have to be plus over plus. + +Why not? It doesn't because it could be M over plus and have no + +effect at offspring by chance, right? But, you were going to say + +it's plus over plus because in the textbooks it's always plus over plus + +in pictures like this, right? And then, it all turns out + +to be pluses and mutants, and pluses and mutants, and all that, + +right? Well, which picture's right? + +Sorry? You don't know. So, that's not good. There's supposed + +to be answers to these things. Could either be true? Which is + +more likely? The one on the left? Why? More statistically probable, + +how come? Because it is. It may not quite suffice as a fully + +complete scientific answer though. + +Yes? Yep. Well, but I have somebody who is affected + +here. So, given that I've gotten affected person in the family -- + +yeah, so it is actually, you're right, statistically somewhat + +less likely that you would have two independent M's entering the same + +pedigree particularly if M is relatively rare. + +If M is quite common, however, suppose M were something + +was a 20% frequency in the population, then it actually might + +be quite reasonable that this could happen. So, what would you really + +want to do to test this? Sorry? Well, if you found any females here + +maybe you'd be able to conclude that it was autosomal recessive because + +females never show a sex-linked trait. Is that true? + +No, that's not true. Why not? You're right. So, you just have to + +be homozygous for it on the X. So, having a single + +female won't, I mean, she's not going to take that as + +evidence. Get an affected female and demonstrate that all of her male + +offspring show the trait. Cross her with, wait, wait. + +This is a human pedigree guys [LAUGHTER]. Whew! There are issues + +involved here, right? You could introduce her to a + +normal guy, [LAUGHTER] but whether you can cross her to a normal guy is + +not actually allowed. So, you see, these are exactly the + +issues in making sense out of pedigrees like this. + +So, what you have to do is you have to collect a lot of data, + +and the kinds of characteristics that you look for in a pedigree, + +but they are statistical characteristics, and + +notwithstanding -- So, this could be colorblindness or + +something, but notwithstanding the pictures in the textbook of + +colorblindness and all that, you really do have to take a look at + +a number of properties. What are some properties? + +One you've already referred to which is there's a predominance in + +males if it's X-linked. Why is there a predominance in + +males? Well, there's a predominance in males because if I + +have an X over Y and I've got a mutation paired on + +this X chromosome, males only have to get it on one. + +Females have to get it on both, and therefore it's statistically more + +likely that males will get it. So, for example, the frequency of + +colorblindness amongst males is what? Yeah, it's 8-10%, + +something like that. I think it's about 8% or so. + +And, amongst females, well, if it's 8% to get one, + +what's the chance you're going to get two? + +It's 8% times 8% is a little less than 1% right? + +It's 0.64%, OK, in females. So, we'll just go 8% + +squared. So in males, 8% in females, less than one percent. + + So, there is a predominance in males + +of these sex-linked traits. Other things: affected males do not + +transmit the trait to the kids, in particular do not transmit it to + +their sons, right, because they are always sending the + +Y chromosomes to their songs. Carrier females + +transmit to half of their sons, and affected females transmit to all + +of their sons. And, the trait appears to skip + +generations, although I don't like this terminology. + +It skips generations. These are the kinds of properties + +that you have. So, hemophilia, + +a good example of this, if I have a child with hemophilia, + +male with hemophilia, would you be surprised if his uncle had + +hemophilia? Which uncle would it be, maternal or paternal? + +The maternal uncle would have hemophilia most likely. + +It's always possible it could be paternal. This is the problem with + +human genetics is you've got to get enough families so the pattern + +becomes overwhelmingly clear, OK, because otherwise, as you can + +see with small numbers, it's tough to be absolutely certain. + +So, these are properties of X linked traits. + +How about baldness? Is baldness, that's a sex-linked + +trait? How come? You don't see a lot of bald females. + +Does that prove it's sex linked? Sorry? Guys are stressed more. + +[LAUGHTER] Is there evidence that it has anything to do with stress? + +Actually, it has to do with excess testosterone it turns out, + +that high levels of testosterone are correlated with male pattern + +baldness, but does the fact that males become bald indicate that this + +is a sex linked trait? No. Just because it's predominant + +in male, we have to check these other properties. + +Is it the case that bald fathers tend to have bald sons? + +Any evidence on this point? Common-sensical evidence from + +observation? It's pretty clear. It's very clearly not a sex-linked + +trait. It's a sex-limited trait, because in order to show this you + +need to be male because the high levels of testosterone are not found + +in females even if they have the genotype that might predispose them + +to become bald if they were male. So, it actually is not a sex-linked + +trait at all, and it's very clear that male pattern baldness does run + +in families more vertically. So, you've got to be careful about + +the difference between sex linked and sex limited, + +and sex linked you can really pick out from transmission and families. + +OK, here's another one. New pedigree. + +She married twice here. OK, what do we got? + +Yep? She married again. She married twice. She didn't have + +any offspring the second time. But that happens, + +and you have to be able to draw it in the pedigree. + +She's entitled, all right. OK, so she got married again, + +no offspring from this marriage. That's her legal symbol. You guys + +think that's funny. It's real, you know? + +OK, that doesn't mean she's married to two people at the same time. + +This is not a temporal picture. So, what do we got here? Yep? + +Sorry, of this person? Well, I'm drawing them as an empty + +symbol here, indicating that we do not think they have the trait. + +They're not carriers. How do you propose to find that out? + +Look at the children. Well, the children are affected. They + +could be carriers. The data are what they are. + +You've got to interpret it. Does this person have to be a + +carrier? What kind of trait do you think this is? + +Dominant? Does this look like autosomal dominant to you? + +Yep? Oh, not all the kids have the trait + +in the first generation, and if this was dominant, + +they'd all have it? What's a possible genotype for this person? + +Mutant over plus. And, these kids could be mutant over plus. + +This could be plus over plus, and this could be plus over plus, + +mutant over plus, plus over plus, mutant over plus, + +and plus over plus would be one possibility. On average, + +what fraction of the kids should get the trait? About half + +the kids, right? So, let's see what characteristics + +we have here. We see the trait in every generation. + +On average, half the kids get the trait. + +Half of the offspring of an affected individual are affected. + +What else? Males and females? Roughly equal in males and females? + +Sorry? One, two, three, + +four, five to two. So, it's a 5:2 ratio? + +Oh, in the offspring it's a 2:1 ratio. So, this is like Mendel. + +You see this number and you say, OK, 2:1. Isn't that trying to tell + +me something? Not with six offspring. That's the problem is + +with six offspring, 2:1 might be trying to tell you 1:1. + +And it is. If I had a dominantly inherited trait where there's a + +50/50 chance of each offspring getting the disease and it was + +autosomal, not sex linked, there would be very good odds of + +getting two males and one female because it happens: flip coins and + +it happens. So, you have to take that into account, + +and here you see what else we have. Roughly equal numbers of males and + +females, they transmit equally, and unaffecteds never transmit. + +This would be the classic autosomal dominant trait. + +Right, here this mutant would go mutant over plus, + +mutant over plus, plus over plus, mutant over plus, plus over plus, + +plus over plus, and you'd see here that three out of + +the five here, and one, two, three out of the six + +there: that's a little more than half but it's small numbers + +here, right? This is a classic autosomal dominant + +as in the textbooks. Yes? Turns out not to make too + +much of a difference. It turns out that there's lots of + +genome that's on either. And so, it is true that males are + +more susceptible to certain genetic diseases. + +So, it'll be some excess, but it won't matter for this. + +Now, in real life it doesn't always work so beautifully. + +We'll take an example: colon cancer. There are particular autosomal + +dominant mutations here that cause a high risk of colon cancer. + +People who have mutations in a certain gene, MLH-1, + +have about a 70% risk of getting colon cancer in their life. + +But notice, it's not 100%. You might have incomplete penetrance. + +Incompletely penetrance means not everybody who gets the genotype gets + +the phenotype. Not all people with the M over plus + +genotype show the phenotype. Once you do that, it messes up our + +picture colossally, because, tell me, + +how do we know that this person over here is not actually M over plus. + +Maybe they're cryptic. They haven't shown the phenotype. + +And maybe, it'll appear in the next generation. That'll screw up + +everything. It screws up our rule about not transmitting through + +unaffected, it screws up the rule about not being shown in + +every generation, and it will even screw up our 50/50 + +ratio because if half the offspring get M over plus, + +but only 70% of that half show the phenotype, then only 35% of the + +offspring will show the phenotype. Unfortunately, this is real life. + +When human geneticists really look at traits, many mutations, + +most except the most severe are incompletely penetrant. + +And so you have to really begin to gather a lot of data to demonstrate + +that you're dealing with an autosomal dominant trait that's + +incompletely penetrant. And then there are other issues. + +There's a gene on chromosome number 17 called BRCA-1, + +mutations in which predisposed to a very high risk of breast cancer but + +only in women. Males carry the mutation and do not + +have breast cancer. There are other mutations that do + +cause breast cancer in males. Males have breast tissue, + +and can have breast cancer, but the one on chromosome 17 does + +not. And so, there you would only see this transmitted through females. + +It would skip into males without showing a phenotype, + +etc. So, in real life, life's a bit more complicated. + +All right, so autosomal dominance. Now, let's take one more pedigree. + +Sorry? Sex limited, but not sex linked. + +So, on chromosome 17, which is a bona fide autosome, + +but it's sex limited in that phenotype can only show itself in an + +individual who happens to be female. Yes? Sorry? How come autosomal + +recessive? So, if that left guy up there is + +actually a heterozygote, and up there that individual, + +so if we had a homozygote, homozygote, heterozygote, + +homozygote, ooh, you can interpret that pedigree if + +you want to as an autosomal recessive, provided that M is pretty + +frequent in the population. That's right. Human geneticists, + +in fact, to really prove that they've got the right model, + +collect a lot of pedigrees and run a computer model. + +The computer model first tries out autosomal recessive, + +tries out autosomal dominant, tries out dominant with incomplete + +penetrance, and for every possible model figures out the statistical + +probability that you would see such data under that model. + +And when the data become overwhelming and you say, + +yeah, with one pedigree, any pedigree I draw on the board, + +it could actually fit almost any for the models. It doesn't say this in + +the textbooks, but it's true. I get enough + +pedigrees, and eventually I say the odds are 105 times more likely that + +this collection of pedigrees would arise from autosomal dominance, + +inheritance with incomplete penetrance of about 80%. + +Then, from autosomal recessive inheritance, then I get to write a + +paper about it. That's really what human + +geneticists do is they have to collect enough, + +now, any other organism, you'd just set up a cross, + +but you can't. And, as long as we have nontrivial models, + +we really have to collect a lot of data. Let's take the next pedigree, + +great, that you're thinking like a human geneticist. + +It's very good. Here's the next pedigree. Actually, + +I'm going to reverse it. There we go. + +What's that? Who knows? You can't tell. Good, I've got you + +up to training to the point where, but in textbooks, this would be + +autosomal recessive. Or it could be anything. + +You know that, right? But the textbooks would show you this + +picture as an autosomal recessive. But of course, what else could it + +be? It could be an autosomal dominant with incomplete penetrance. + +It could be sex linked. It could be a lot of things. + +It could also be, I haven't told you the phenotype. + +What if the phenotype here was getting hit by a truck? + +[LAUGHTER] Would you tend to observe this? Yep, + +so getting hit by a truck, for example, if someone gets hit by + +a truck, it's unlikely either their parents were hit by a truck, + +or going back several generations that their grandparents were hit by + +a truck. So, how do you tell being hit by a truck from, + +I mean, that is to say, how do you know that something's + +genetic at all? When it's relatively rare and it + +pops up in a pedigree, how do you know it's genetic? + +Because of the DNA. But, I mean, it takes a lot of work to find the + +gene and all that as we'll come to the course. You might want a little + +bit of assurance before you go write the grant to the NIH and say I'm + +going to find the gene for this because you write it and say I'm + +going to find the gene for getting hit by a truck, + +and they're going to write back and say show me that it's worth spending + +money to find that gene. Show me that it's true. So, + +what kind of things would we look for? If we wanted to show something + +was autosomal recessive in a population, what would we do? + +More data. So, we collect a lot of families, + +and what would we see? As we collected more and more families, + +we begin to see what things? Sometimes we might see families like + +this, or we might see families like this. [LAUGHTER] + +If both parents were mutants, all the children would be mutant, + +right? We'd color them in mutant. Is that true? Well, first off, it + +depends. Some of the things we want to study are extremely severe + +medical genetical phenotypes, and they're not going to live to + +have children. So, that's an issue that you have + +to deal with. But, it is true that if it was + +autosomal recessive, a mating between two homozygotes for + +that gene would transmit. [LAUGHTER] What if they were all in + +the same car? Which is a very important part, + +because we joke about the car, but diet, things like that, are + +familial correlated environmental factors. There are environmental + +factors that correlate within a family. + +And so, it's not trivial to make this point. So, + +all right, we'll be able to demonstrate what's the real proof of + +Mendelian inheritance here? Because they could all be in the + +same car, or they all eat the same kind of food or something like that, + +which predisposes them a certain way. So, we're going to want some better + +proofs of these things. How about Mendelian ratios? + +Mendelian ratios anyone? No, because it could be incomplete + +autosomal dominance. I don't want to mess you up. + +On the exams, you guys can think cleanly about simple things. + +But, this could be dominant with incomplete penetrance, + +though the TA's are going to hate me because I'm telling you that, + +anyway, what about Mendelian ratios? How about something that's a pretty + +good prediction? What fraction of the offspring will + +be affected? We get a lot of families, + +line them all up. What fraction of the offspring? + +A quarter. Now, that's a hard and fast prediction. + +One quarter of the offspring are effective. When I have a mating + +between two homozygotes, so what am I going to do? + +I'm going to go out. I'm going to collect a lot of families. + +Maybe I'll collect 100 families because it'll be a particular + +disease, diastrophic dysplasia or something like that, + +xeroderma pygmentosa, ataxia teleangiectasia, + +and I will go to the disease foundation, and I will get all the + +pedigrees for all the families, and I'll see how many times it was + +one affected, two affected, three affected, etc. And on average, + +the proportion affecteds will be a quarter, except it's not true. + +If I actually do that, I find that the ratio of affecteds is typically + +more like a third. It isn't a quarter. + +Now, this should disturb you greatly because you know full well + +that M over plus by M over plus should give you a quarter affecteds. + +But when you actually look at human families, it's not. + +Why? In other words, when we count up all the matings + +between heterozygotes, we'll collect all the matings that + +produce one affected child. We'll collect all the matings that + +produce two affected children. We'll collect all the matings that + +produce three affected children. But, we will fail to collect those + +matings between homozygotes that produce zero affected children. + +And so, we will systematically overestimate the proportion. + +Of course, what we really have to do is go out and get all of those + +couples who were both carriers, but because they had a small number + +of children didn't happen to have an affected child. + +That's not very easy to do especially when you don't know the + +gene in advance. So, when human geneticists try to + +go out and measure the one-quarter Mendelian ratio, + +you can't. But what you can do is the following, + +conditional on the first trial being affected, now what will be the + +proportion of subsequent children who are affected? + +A quarter. If I make it conditional, conditioning on having a first child + +who's affected, number one child who's affected, + +then I know I've got a mating between heterozygotes. + +Subsequent offspring now do not have that bias. + +And so, as a matter of fact, you think this pretty cool thought, + +right? You've got a condition on one. It turns out there's a very + +famous paper about cystic fibrosis where somebody forgot this point and + +made a huge big deal in the literature about the fact that a + +third of the kids on average had cystic fibrosis in these + +families, and proposed all sorts of models about how cystic fibrosis + +might be advantageous and would lead to fertility increases and all that. + +In fact, it was just a failure to correct for this little statistical + +bias. OK, this is what human geneticists do is they've got to + +deal with the popular, now, there's one other trick that + +you can use to know that something is autosomal recessive. + +That trick is this. To site this trick, + +I have to go back to a person called Archibald Garrett. + +Archibald Garrett was a physician in London around 1900. + +Garrett studied children with the trait alkoptonuria. + +Alkoptonuria was what alkopton means black. Uria means urine. + +They had black urine. This was evident because their urine turned + +black on treatment with alkaline. How would you treat urine with + +alkaline. How would people know this? Sorry? Outhouses with lime, + +yeah, and who's going to look at the children's urine, or something + +like that? But you're on the right track. + +How about diapers? You wash diapers, cloth diapers, + +in alkaline. They turn black. This was evident from black diapers. + +The kids' urine would turn black. So, he observed this, and you know + +what Garrett noticed is when he studied, children alkoptonuria, + +he found that a very large fraction of affected + +offspring were in fact produced from matings of first cousins. + +Consanguineous matings: now you laugh, but in fact consanguinity has + +been something that has been favored in many societies, + +and in Britain, particularly amongst the upper class + +in Britain in 1900, marriage or first cousins was quite + +common, but not as common as he observed. He found that eight out + +of 17 alkoptonuria patients were the products of first cousin marriages. + +That's way off the charts because it's nearly a half, + +when in fact the typical rate in Britain might have been about 5%. + +So, on the basis of that in the early 1900's, Garrett was able to + +show only a few years after the rediscovery of Mendel's work that + +this property of recessive traits, enrichment in the offspring of + +consanguineous marriages, was a clear demonstration of + +Mendelian inheritance. Not only did he do that, + +but Garrett knew because of the work of some biochemists, + +and this is way cool, that the problem with the urine was + +that these patients put out in their urine a lot of what's called + +homogentisic acid, HGA, which basically is a phenolic + +ring. What Garrett did was he, and that stuff turns black on + +exposure to air. What might produce from the things + +you've learned already some kind of ring like that? + +What building blocks do you know have rings like that of things + +you've studied already? Phenylalanine, tyrosine both have + +rings. Suppose somebody had problems breaking down homogentisic + +acid. Suppose there was some pathway where proteins were + +broken down into amino acids including phenylalanine + +and tyrosine. And, they were broken down into + +homogentisic acid. And they were broken down into I + +don't know what. And, suppose like we had up there, + +patients had a mutation in that enzyme. What would happen if I fed + +patients a lot of protein? In their urine, you would recover + +lots of homogentisic acid. Suppose I fed them a lot of tyrosine. + +I'd get a lot of homogentisic acid because the body couldn't break it + +down. Suppose I fed them a lot of phenylalanine. + +They would excrete a lot of homogentisic acid. + +Suppose I fed them homogentisic acid. I would get quantitative + +amounts of homogentisic acid. Garrett did this. These are the + +days before institutional review boards, you know, + +informed consent. It turns out it's harmless feeding them proteins and + +things like that. But in fact, Garrett, + +in 1911, worked out that this trait had to be recessive because of its + +population genetics, and inferred a biochemical pathway + +by feeding different things along the way and was able to connect a + +mutation in a gene to a problem with a specific biochemical pathway. + +Sorry, 1908: this was his Croonian Lecture in 1908. + +Eight years after the rediscovery of Mendel, he's able to connect + +genetic defect, showing it's genetic by transmission, + +to biochemical defect showing that he has a pathway that he can feed + +things into. And, it all blocks up at the inability to + +metabolize homogentisic acid. He has connected gene to enzyme by + +1908. What do you think the reaction to + +this was? Polite bewilderment, and it sunk like a stone. Nobody + +was prepared to hear this. This is very much like Mendel in my + +opinion. Now, he was a distinguished professor. + +It was the Croonian Lecture. He got lots of accolades and all that, + +and people said, what a lovely lecture that was, + +and proceeded to completely forget this connection between genes and + +enzymes, genes and proteins. It was not until 40 years later or + +so that Beadle and Tatum, working with a fungus, actually + +rosper not yeast, demonstrated that all these mutants + +interfered with the ability to digest or to make particular amino + +acids, and wrote this up as the one gene, one enzyme hypothesis of how + +genes encode enzymes, and won the Nobel Prize for this + +work, but in fact in their Nobel address, + +Beetle and Tatum noted, actually, you know, Garrett kind of + +knew all this. But, people weren't ready, + +yet, to digest it. Genetics had just come along, + +Biochemistry had just really been invented in the last ten years, + +and the idea of uniting genetics and biochemistry was just something + +people weren't prepared for yet. More next time. \ No newline at end of file diff --git a/PbITFIGLciI.txt b/PbITFIGLciI.txt new file mode 100644 index 0000000000000000000000000000000000000000..bd76f1e9b40d026d42991588fb1621932819db2f --- /dev/null +++ b/PbITFIGLciI.txt @@ -0,0 +1,6627 @@ +align:start position:0% + +foreign + + align:start position:0% + + + + align:start position:0% + +I think we'll go ahead and get started + + align:start position:0% +I think we'll go ahead and get started + + + align:start position:0% +I think we'll go ahead and get started +hello everyone + + align:start position:0% +hello everyone + + + align:start position:0% +hello everyone +welcome to 8225 which is also + + align:start position:0% +welcome to 8225 which is also + + + align:start position:0% +welcome to 8225 which is also +sts042 physics in the 20th century + + align:start position:0% +sts042 physics in the 20th century + + + align:start position:0% +sts042 physics in the 20th century +uh my name is David Kaiser um today's + + align:start position:0% +uh my name is David Kaiser um today's + + + align:start position:0% +uh my name is David Kaiser um today's +class is um gonna be a little shorter + + align:start position:0% +class is um gonna be a little shorter + + + align:start position:0% +class is um gonna be a little shorter +than average I just want to go over a + + align:start position:0% +than average I just want to go over a + + + align:start position:0% +than average I just want to go over a +kind of quick introduction for the + + align:start position:0% +kind of quick introduction for the + + + align:start position:0% +kind of quick introduction for the +course an overview some Logistics course + + align:start position:0% +course an overview some Logistics course + + + align:start position:0% +course an overview some Logistics course +structure and so on and then we'll jump + + align:start position:0% +structure and so on and then we'll jump + + + align:start position:0% +structure and so on and then we'll jump +in with the first sort of full + + align:start position:0% +in with the first sort of full + + + align:start position:0% +in with the first sort of full +um class session uh next week so I'm + + align:start position:0% +um class session uh next week so I'm + + + align:start position:0% +um class session uh next week so I'm +going to go ahead and share my screen I + + align:start position:0% +going to go ahead and share my screen I + + + align:start position:0% +going to go ahead and share my screen I +have some slides just to help kind of + + align:start position:0% +have some slides just to help kind of + + + align:start position:0% +have some slides just to help kind of +Orient us for today's session + + align:start position:0% +Orient us for today's session + + + align:start position:0% +Orient us for today's session +so + + align:start position:0% +so + + + align:start position:0% +so +let's do that + + align:start position:0% +let's do that + + + align:start position:0% +let's do that +and that and now hopefully you can see + + align:start position:0% +and that and now hopefully you can see + + + align:start position:0% +and that and now hopefully you can see +my screen there another some nods or + + align:start position:0% +my screen there another some nods or + + + align:start position:0% +my screen there another some nods or +thumbs up so far so good + + align:start position:0% +thumbs up so far so good + + + align:start position:0% +thumbs up so far so good +thank you okay great so welcome to + + align:start position:0% +thank you okay great so welcome to + + + align:start position:0% +thank you okay great so welcome to +um to the new semester uh this is a + + align:start position:0% +um to the new semester uh this is a + + + align:start position:0% +um to the new semester uh this is a +class I've taught many many times I've + + align:start position:0% +class I've taught many many times I've + + + align:start position:0% +class I've taught many many times I've +been teaching at MIT since 2000 which + + align:start position:0% +been teaching at MIT since 2000 which + + + align:start position:0% +been teaching at MIT since 2000 which +itself is now historical it feels like a + + align:start position:0% +itself is now historical it feels like a + + + align:start position:0% +itself is now historical it feels like a +long time and I've taught this course + + align:start position:0% +long time and I've taught this course + + + align:start position:0% +long time and I've taught this course +probably every other year or more or + + align:start position:0% +probably every other year or more or + + + align:start position:0% +probably every other year or more or +less over that time period so I've + + align:start position:0% +less over that time period so I've + + + align:start position:0% +less over that time period so I've +taught at least 10 or 11 times or so and + + align:start position:0% +taught at least 10 or 11 times or so and + + + align:start position:0% +taught at least 10 or 11 times or so and +I have to say + + align:start position:0% +I have to say + + + align:start position:0% +I have to say +um if I may say so myself it's my + + align:start position:0% +um if I may say so myself it's my + + + align:start position:0% +um if I may say so myself it's my +favorite course that I teach um + + align:start position:0% +favorite course that I teach um + + + align:start position:0% +favorite course that I teach um +hopefully it'll be a positive experience + + align:start position:0% +hopefully it'll be a positive experience + + + align:start position:0% +hopefully it'll be a positive experience +for you as well I think it's a really + + align:start position:0% +for you as well I think it's a really + + + align:start position:0% +for you as well I think it's a really +fun opportunity + + align:start position:0% +fun opportunity + + + align:start position:0% +fun opportunity +to um to sort of sit with some material + + align:start position:0% +to um to sort of sit with some material + + + align:start position:0% +to um to sort of sit with some material +that might be familiar to many of you we + + align:start position:0% +that might be familiar to many of you we + + + align:start position:0% +that might be familiar to many of you we +have many folks who are physics Majors + + align:start position:0% +have many folks who are physics Majors + + + align:start position:0% +have many folks who are physics Majors +many of them are Juniors and seniors + + align:start position:0% +many of them are Juniors and seniors + + + align:start position:0% +many of them are Juniors and seniors +it's also um hopefully an interesting + + align:start position:0% +it's also um hopefully an interesting + + + align:start position:0% +it's also um hopefully an interesting +kind of preview for um for students who + + align:start position:0% +kind of preview for um for students who + + + align:start position:0% +kind of preview for um for students who +either are not in the physics department + + align:start position:0% +either are not in the physics department + + + align:start position:0% +either are not in the physics department +or newer to MIT and so on and I think + + align:start position:0% +or newer to MIT and so on and I think + + + align:start position:0% +or newer to MIT and so on and I think +it's just it's a kind of remarkable + + align:start position:0% +it's just it's a kind of remarkable + + + align:start position:0% +it's just it's a kind of remarkable +set of of ideas and institutions and + + align:start position:0% +set of of ideas and institutions and + + + align:start position:0% +set of of ideas and institutions and +events and people that we get to kind of + + align:start position:0% +events and people that we get to kind of + + + align:start position:0% +events and people that we get to kind of +sit with over the course of the semester + + align:start position:0% +sit with over the course of the semester + + + align:start position:0% +sit with over the course of the semester +so + + align:start position:0% +so + + + align:start position:0% +so +um so you know it's a new adventure + + align:start position:0% +um so you know it's a new adventure + + + align:start position:0% +um so you know it's a new adventure +doing this remotely by Zoom but I hope + + align:start position:0% +doing this remotely by Zoom but I hope + + + align:start position:0% +doing this remotely by Zoom but I hope +we get to uh to really enjoy the kind of + + align:start position:0% +we get to uh to really enjoy the kind of + + + align:start position:0% +we get to uh to really enjoy the kind of +pretty wacky ideas and some unusual + + align:start position:0% +pretty wacky ideas and some unusual + + + align:start position:0% +pretty wacky ideas and some unusual +times and places that we get to immerse + + align:start position:0% +times and places that we get to immerse + + + align:start position:0% +times and places that we get to immerse +ourselves in as well + + align:start position:0% +ourselves in as well + + + align:start position:0% +ourselves in as well +and I try to just just enjoy that with + + align:start position:0% +and I try to just just enjoy that with + + + align:start position:0% +and I try to just just enjoy that with +some of these opening images here on on + + align:start position:0% +some of these opening images here on on + + + align:start position:0% +some of these opening images here on on +the on the first slide + + align:start position:0% +the on the first slide + + + align:start position:0% +the on the first slide +so today as I mentioned it's not going + + align:start position:0% +so today as I mentioned it's not going + + + align:start position:0% +so today as I mentioned it's not going +to be a full I don't expect to be a full + + align:start position:0% +to be a full I don't expect to be a full + + + align:start position:0% +to be a full I don't expect to be a full +class session + + align:start position:0% +class session + + + align:start position:0% +class session +um but I do want to give an overview of + + align:start position:0% +um but I do want to give an overview of + + + align:start position:0% +um but I do want to give an overview of +kind of where we're going and also some + + align:start position:0% +kind of where we're going and also some + + + align:start position:0% +kind of where we're going and also some +some of the kind of nuts and bolts and + + align:start position:0% +some of the kind of nuts and bolts and + + + align:start position:0% +some of the kind of nuts and bolts and +Logistics + + align:start position:0% +Logistics + + + align:start position:0% +Logistics +so anyway the plan for today we'll talk + + align:start position:0% +so anyway the plan for today we'll talk + + + align:start position:0% +so anyway the plan for today we'll talk +about the course aims we'll talk a bit + + align:start position:0% +about the course aims we'll talk a bit + + + align:start position:0% +about the course aims we'll talk a bit +about the instructors give the teaching + + align:start position:0% +about the instructors give the teaching + + + align:start position:0% +about the instructors give the teaching +assistance a chance to just introduce + + align:start position:0% +assistance a chance to just introduce + + + align:start position:0% +assistance a chance to just introduce +themselves and say quick hello as well + + align:start position:0% +themselves and say quick hello as well + + + align:start position:0% +themselves and say quick hello as well +we'll give we'll talk about the course + + align:start position:0% +we'll give we'll talk about the course + + + align:start position:0% +we'll give we'll talk about the course +structure uh and the requirements of the + + align:start position:0% +structure uh and the requirements of the + + + align:start position:0% +structure uh and the requirements of the +course and then I'll give a kind of + + align:start position:0% +course and then I'll give a kind of + + + align:start position:0% +course and then I'll give a kind of +brief overview of the kinds of material + + align:start position:0% +brief overview of the kinds of material + + + align:start position:0% +brief overview of the kinds of material +that we'll be engaging with in more + + align:start position:0% +that we'll be engaging with in more + + + align:start position:0% +that we'll be engaging with in more +detail starting next week so that's + + align:start position:0% +detail starting next week so that's + + + align:start position:0% +detail starting next week so that's +where we're at + + align:start position:0% +where we're at + + + align:start position:0% +where we're at +so here I'm just taking the subject + + align:start position:0% +so here I'm just taking the subject + + + align:start position:0% +so here I'm just taking the subject +description uh right from the front page + + align:start position:0% +description uh right from the front page + + + align:start position:0% +description uh right from the front page +of the syllabus just to give you a sense + + align:start position:0% +of the syllabus just to give you a sense + + + align:start position:0% +of the syllabus just to give you a sense +of what where we're heading + + align:start position:0% +of what where we're heading + + + align:start position:0% +of what where we're heading +over the term + + align:start position:0% +over the term + + + align:start position:0% +over the term +the class is meant to explore the + + align:start position:0% +the class is meant to explore the + + + align:start position:0% +the class is meant to explore the +changing roles of physics and physicists + + align:start position:0% +changing roles of physics and physicists + + + align:start position:0% +changing roles of physics and physicists +over really not just the 20th century + + align:start position:0% +over really not just the 20th century + + + align:start position:0% +over really not just the 20th century +anymore by now we're going to be up to + + align:start position:0% +anymore by now we're going to be up to + + + align:start position:0% +anymore by now we're going to be up to +just about two centuries worth of + + align:start position:0% +just about two centuries worth of + + + align:start position:0% +just about two centuries worth of +material uh for the first main class + + align:start position:0% +material uh for the first main class + + + align:start position:0% +material uh for the first main class +next week I'll be starting with the + + align:start position:0% +next week I'll be starting with the + + + align:start position:0% +next week I'll be starting with the +1820s which it turns out is now 200 + + align:start position:0% +1820s which it turns out is now 200 + + + align:start position:0% +1820s which it turns out is now 200 +years ago so really it's an expanse of + + align:start position:0% +years ago so really it's an expanse of + + + align:start position:0% +years ago so really it's an expanse of +you not not only uh the 20th century + + align:start position:0% +you not not only uh the 20th century + + + align:start position:0% +you not not only uh the 20th century +we're going to quickly bring ourselves + + align:start position:0% +we're going to quickly bring ourselves + + + align:start position:0% +we're going to quickly bring ourselves +up into what we often call Modern + + align:start position:0% +up into what we often call Modern + + + align:start position:0% +up into what we often call Modern +physics relativity quantum theory again + + align:start position:0% +physics relativity quantum theory again + + + align:start position:0% +physics relativity quantum theory again +which might be familiar to many of you + + align:start position:0% +which might be familiar to many of you + + + align:start position:0% +which might be familiar to many of you +might be new to others + + align:start position:0% +might be new to others + + + align:start position:0% +might be new to others +um and then we're going to zoom forward + + align:start position:0% +um and then we're going to zoom forward + + + align:start position:0% +um and then we're going to zoom forward +even beyond that that early uh ferment + + align:start position:0% +even beyond that that early uh ferment + + + align:start position:0% +even beyond that that early uh ferment +of the early 20th century and uh look at + + align:start position:0% +of the early 20th century and uh look at + + + align:start position:0% +of the early 20th century and uh look at +much more recent developments in high + + align:start position:0% +much more recent developments in high + + + align:start position:0% +much more recent developments in high +energy physics uh in cosmology and + + align:start position:0% +energy physics uh in cosmology and + + + align:start position:0% +energy physics uh in cosmology and +astrophysics my own personal favorite + + align:start position:0% +astrophysics my own personal favorite + + + align:start position:0% +astrophysics my own personal favorite +topics uh and we're going to be + + align:start position:0% +topics uh and we're going to be + + + align:start position:0% +topics uh and we're going to be +examining these intellectual + + align:start position:0% +examining these intellectual + + + align:start position:0% +examining these intellectual +developments these conceptual and + + align:start position:0% +developments these conceptual and + + + align:start position:0% +developments these conceptual and +intellectual developments at each moment + + align:start position:0% +intellectual developments at each moment + + + align:start position:0% +intellectual developments at each moment +we're trying to understand they're kind + + align:start position:0% +we're trying to understand they're kind + + + align:start position:0% +we're trying to understand they're kind +of embedding in a very messy uh human + + align:start position:0% +of embedding in a very messy uh human + + + align:start position:0% +of embedding in a very messy uh human +world in a changing human world so part + + align:start position:0% +world in a changing human world so part + + + align:start position:0% +world in a changing human world so part +of our goal for this semester is both to + + align:start position:0% +of our goal for this semester is both to + + + align:start position:0% +of our goal for this semester is both to +kind of learn or reiterate some pretty + + align:start position:0% +kind of learn or reiterate some pretty + + + align:start position:0% +kind of learn or reiterate some pretty +amazing ideas for modern physics uh + + align:start position:0% +amazing ideas for modern physics uh + + + align:start position:0% +amazing ideas for modern physics uh +might be new to some might be familiar + + align:start position:0% +might be new to some might be familiar + + + align:start position:0% +might be new to some might be familiar +to others who've got to sit with those + + align:start position:0% +to others who've got to sit with those + + + align:start position:0% +to others who've got to sit with those +ideas but also do a lot more work in + + align:start position:0% +ideas but also do a lot more work in + + + align:start position:0% +ideas but also do a lot more work in +practice of embedding those ideas uh in + + align:start position:0% +practice of embedding those ideas uh in + + + align:start position:0% +practice of embedding those ideas uh in +a in an historical + + align:start position:0% +a in an historical + + + align:start position:0% +a in an historical +um kind of a development then that means + + align:start position:0% +um kind of a development then that means + + + align:start position:0% +um kind of a development then that means +looking at institutions at cultural uh + + align:start position:0% +looking at institutions at cultural uh + + + align:start position:0% +looking at institutions at cultural uh +uh features of how people have thought + + align:start position:0% +uh features of how people have thought + + + align:start position:0% +uh features of how people have thought +about physics and physicists physicists + + align:start position:0% +about physics and physicists physicists + + + align:start position:0% +about physics and physicists physicists +and cells have been part of larger + + align:start position:0% +and cells have been part of larger + + + align:start position:0% +and cells have been part of larger +social worlds political context wartime + + align:start position:0% +social worlds political context wartime + + + align:start position:0% +social worlds political context wartime +and so on and so over the course this + + align:start position:0% +and so on and so over the course this + + + align:start position:0% +and so on and so over the course this +semester we're going to be looking at + + align:start position:0% +semester we're going to be looking at + + + align:start position:0% +semester we're going to be looking at +not just a range of ideas but a range of + + align:start position:0% +not just a range of ideas but a range of + + + align:start position:0% +not just a range of ideas but a range of +places in which those ideas have been + + align:start position:0% +places in which those ideas have been + + + align:start position:0% +places in which those ideas have been +pursued or cultivated or argued over or + + align:start position:0% +pursued or cultivated or argued over or + + + align:start position:0% +pursued or cultivated or argued over or +debated or rejected so we'll start + + align:start position:0% +debated or rejected so we'll start + + + align:start position:0% +debated or rejected so we'll start +looking at + + align:start position:0% +looking at + + + align:start position:0% +looking at +Britain from uh in the 19th century + + align:start position:0% +Britain from uh in the 19th century + + + align:start position:0% +Britain from uh in the 19th century +that's where we'll begin much of our + + align:start position:0% +that's where we'll begin much of our + + + align:start position:0% +that's where we'll begin much of our +investigation for this semester we'll + + align:start position:0% +investigation for this semester we'll + + + align:start position:0% +investigation for this semester we'll +look at + + align:start position:0% +look at + + + align:start position:0% +look at +newly unified Germany in the 1870s + + align:start position:0% +newly unified Germany in the 1870s + + + align:start position:0% +newly unified Germany in the 1870s +moving forward in time ultimately to the + + align:start position:0% +moving forward in time ultimately to the + + + align:start position:0% +moving forward in time ultimately to the +first world war to the rise of Nazism to + + align:start position:0% +first world war to the rise of Nazism to + + + align:start position:0% +first world war to the rise of Nazism to +the second world war lots of kind of big + + align:start position:0% +the second world war lots of kind of big + + + align:start position:0% +the second world war lots of kind of big +uh consequential worldly events which as + + align:start position:0% +uh consequential worldly events which as + + + align:start position:0% +uh consequential worldly events which as +I hope we'll we'll get to appreciate + + align:start position:0% +I hope we'll we'll get to appreciate + + + align:start position:0% +I hope we'll we'll get to appreciate +over the course the term had a really + + align:start position:0% +over the course the term had a really + + + align:start position:0% +over the course the term had a really +quite remarkable impact on the + + align:start position:0% +quite remarkable impact on the + + + align:start position:0% +quite remarkable impact on the +intellectual world of physics and + + align:start position:0% +intellectual world of physics and + + + align:start position:0% +intellectual world of physics and +physicists and we'll bring the story up + + align:start position:0% +physicists and we'll bring the story up + + + align:start position:0% +physicists and we'll bring the story up +through the second world war and into + + align:start position:0% +through the second world war and into + + + align:start position:0% +through the second world war and into +the cold war and even Beyond so we have + + align:start position:0% +the cold war and even Beyond so we have + + + align:start position:0% +the cold war and even Beyond so we have +a long timeline uh really as I say the + + align:start position:0% +a long timeline uh really as I say the + + + align:start position:0% +a long timeline uh really as I say the +better part of two Centuries by now to + + align:start position:0% +better part of two Centuries by now to + + + align:start position:0% +better part of two Centuries by now to +to to sample over and I think a pretty + + align:start position:0% +to to sample over and I think a pretty + + + align:start position:0% +to to sample over and I think a pretty +nice broad range of ideas in physics as + + align:start position:0% +nice broad range of ideas in physics as + + + align:start position:0% +nice broad range of ideas in physics as +well + + align:start position:0% +well + + + align:start position:0% +well +um + + align:start position:0% +um + + + align:start position:0% +um +and so just sort of pictorially uh some + + align:start position:0% +and so just sort of pictorially uh some + + + align:start position:0% +and so just sort of pictorially uh some +of the early moments will be will be + + align:start position:0% +of the early moments will be will be + + + align:start position:0% +of the early moments will be will be +kind of um thinking about are the turn + + align:start position:0% +kind of um thinking about are the turn + + + align:start position:0% +kind of um thinking about are the turn +of the 19th into the 20th century uh + + align:start position:0% +of the 19th into the 20th century uh + + + align:start position:0% +of the 19th into the 20th century uh +when a lot of research was still + + align:start position:0% +when a lot of research was still + + + align:start position:0% +when a lot of research was still +um sort of tabletop scale here's a + + align:start position:0% +um sort of tabletop scale here's a + + + align:start position:0% +um sort of tabletop scale here's a +photograph of uh Pierre and Marie Curie + + align:start position:0% +photograph of uh Pierre and Marie Curie + + + align:start position:0% +photograph of uh Pierre and Marie Curie +and their uh laboratory in Paris from uh + + align:start position:0% +and their uh laboratory in Paris from uh + + + align:start position:0% +and their uh laboratory in Paris from uh +right around the year 1900 where the + + align:start position:0% +right around the year 1900 where the + + + align:start position:0% +right around the year 1900 where the +scale of apparatus if not phenomenal + + align:start position:0% +scale of apparatus if not phenomenal + + + align:start position:0% +scale of apparatus if not phenomenal +still felt kind of human scaled also a + + align:start position:0% +still felt kind of human scaled also a + + + align:start position:0% +still felt kind of human scaled also a +bit kind of removed from other elements + + align:start position:0% +bit kind of removed from other elements + + + align:start position:0% +bit kind of removed from other elements +of Human Experience this was a a + + align:start position:0% +of Human Experience this was a a + + + align:start position:0% +of Human Experience this was a a +laboratory pursuing esoteric questions + + align:start position:0% +laboratory pursuing esoteric questions + + + align:start position:0% +laboratory pursuing esoteric questions +in a specialized community + + align:start position:0% +in a specialized community + + + align:start position:0% +in a specialized community +before too long as I'm sure many of you + + align:start position:0% +before too long as I'm sure many of you + + + align:start position:0% +before too long as I'm sure many of you +already know + + align:start position:0% +already know + + + align:start position:0% +already know +many of those investigations began + + align:start position:0% +many of those investigations began + + + align:start position:0% +many of those investigations began +having a much more dramatic worldly + + align:start position:0% +having a much more dramatic worldly + + + align:start position:0% +having a much more dramatic worldly +impact it will look quite a bit in this + + align:start position:0% +impact it will look quite a bit in this + + + align:start position:0% +impact it will look quite a bit in this +course at the work on nuclear weapons + + align:start position:0% +course at the work on nuclear weapons + + + align:start position:0% +course at the work on nuclear weapons +the use of nuclear weapons in the second + + align:start position:0% +the use of nuclear weapons in the second + + + align:start position:0% +the use of nuclear weapons in the second +world war a whole different Arrangement + + align:start position:0% +world war a whole different Arrangement + + + align:start position:0% +world war a whole different Arrangement +between scientists engineers nation + + align:start position:0% +between scientists engineers nation + + + align:start position:0% +between scientists engineers nation +states and world affairs So within not a + + align:start position:0% +states and world affairs So within not a + + + align:start position:0% +states and world affairs So within not a +long stretch of time we go from + + align:start position:0% +long stretch of time we go from + + + align:start position:0% +long stretch of time we go from +photographs like the curies over here to + + align:start position:0% +photographs like the curies over here to + + + align:start position:0% +photographs like the curies over here to +something like this where you have + + align:start position:0% +something like this where you have + + + align:start position:0% +something like this where you have +Robert Oppenheimer with his famous pork + + align:start position:0% +Robert Oppenheimer with his famous pork + + + align:start position:0% +Robert Oppenheimer with his famous pork +pie hat working side by side with the + + align:start position:0% +pie hat working side by side with the + + + align:start position:0% +pie hat working side by side with the +Army General uh Leslie Groves at the U.S + + align:start position:0% +Army General uh Leslie Groves at the U.S + + + align:start position:0% +Army General uh Leslie Groves at the U.S +army uh inspecting in this case the site + + align:start position:0% +army uh inspecting in this case the site + + + align:start position:0% +army uh inspecting in this case the site +of the very first test detonation of a + + align:start position:0% +of the very first test detonation of a + + + align:start position:0% +of the very first test detonation of a +nuclear weapon in July 1945. + + align:start position:0% +nuclear weapon in July 1945. + + + align:start position:0% +nuclear weapon in July 1945. +just 75 years ago + + align:start position:0% +just 75 years ago + + + align:start position:0% +just 75 years ago +soon after that as again many of you + + align:start position:0% +soon after that as again many of you + + + align:start position:0% +soon after that as again many of you +probably know + + align:start position:0% +probably know + + + align:start position:0% +probably know +um physics and physicists move into a + + align:start position:0% +um physics and physicists move into a + + + align:start position:0% +um physics and physicists move into a +new kind of Vantage + + align:start position:0% +new kind of Vantage + + + align:start position:0% +new kind of Vantage +um culturally and politically here's a + + align:start position:0% +um culturally and politically here's a + + + align:start position:0% +um culturally and politically here's a +famous Time Magazine cover of Einstein + + align:start position:0% +famous Time Magazine cover of Einstein + + + align:start position:0% +famous Time Magazine cover of Einstein +with uh his most famous equation E + + align:start position:0% +with uh his most famous equation E + + + align:start position:0% +with uh his most famous equation E +equals MC squared appearing eerily in + + align:start position:0% +equals MC squared appearing eerily in + + + align:start position:0% +equals MC squared appearing eerily in +the mushroom cloud of a nuclear + + align:start position:0% +the mushroom cloud of a nuclear + + + align:start position:0% +the mushroom cloud of a nuclear +explosion so the associations between + + align:start position:0% +explosion so the associations between + + + align:start position:0% +explosion so the associations between +physics and physicists were changing + + align:start position:0% +physics and physicists were changing + + + align:start position:0% +physics and physicists were changing +very quickly especially after the second + + align:start position:0% +very quickly especially after the second + + + align:start position:0% +very quickly especially after the second +world war we're going to explore a lot + + align:start position:0% +world war we're going to explore a lot + + + align:start position:0% +world war we're going to explore a lot +of that + + align:start position:0% +of that + + + align:start position:0% +of that +um over the course of semester + + align:start position:0% +um over the course of semester + + + align:start position:0% +um over the course of semester +and then zooming forward we get to where + + align:start position:0% +and then zooming forward we get to where + + + align:start position:0% +and then zooming forward we get to where +the scale of apparatus no longer fits on + + align:start position:0% +the scale of apparatus no longer fits on + + + align:start position:0% +the scale of apparatus no longer fits on +a Parisian tabletop but in fact this is + + align:start position:0% +a Parisian tabletop but in fact this is + + + align:start position:0% +a Parisian tabletop but in fact this is +a a photograph from what would have been + + align:start position:0% +a a photograph from what would have been + + + align:start position:0% +a a photograph from what would have been +the world's largest particle accelerator + + align:start position:0% +the world's largest particle accelerator + + + align:start position:0% +the world's largest particle accelerator +some of you might have heard of it the + + align:start position:0% +some of you might have heard of it the + + + align:start position:0% +some of you might have heard of it the +superconducting super collider or SSC if + + align:start position:0% +superconducting super collider or SSC if + + + align:start position:0% +superconducting super collider or SSC if +you haven't heard about it it's because + + align:start position:0% +you haven't heard about it it's because + + + align:start position:0% +you haven't heard about it it's because +it was never finished this would have + + align:start position:0% +it was never finished this would have + + + align:start position:0% +it was never finished this would have +dwarfed even the Large Hadron Collider + + align:start position:0% +dwarfed even the Large Hadron Collider + + + align:start position:0% +dwarfed even the Large Hadron Collider +that is in operation uh in CERN in + + align:start position:0% +that is in operation uh in CERN in + + + align:start position:0% +that is in operation uh in CERN in +Geneva this was a machine the + + align:start position:0% +Geneva this was a machine the + + + align:start position:0% +Geneva this was a machine the +superconducting super collider that was + + align:start position:0% +superconducting super collider that was + + + align:start position:0% +superconducting super collider that was +under construction in uh Texas not too + + align:start position:0% +under construction in uh Texas not too + + + align:start position:0% +under construction in uh Texas not too +far from Dallas it was actually halted + + align:start position:0% +far from Dallas it was actually halted + + + align:start position:0% +far from Dallas it was actually halted +in 1993 after the engineers had already + + align:start position:0% +in 1993 after the engineers had already + + + align:start position:0% +in 1993 after the engineers had already +dug a 54 mile circumference tunnel + + align:start position:0% +dug a 54 mile circumference tunnel + + + align:start position:0% +dug a 54 mile circumference tunnel +underground roughly three times longer + + align:start position:0% +underground roughly three times longer + + + align:start position:0% +underground roughly three times longer +than the Large Hadron Collider + + align:start position:0% +than the Large Hadron Collider + + + align:start position:0% +than the Large Hadron Collider +so the scale of our apparatus is no + + align:start position:0% +so the scale of our apparatus is no + + + align:start position:0% +so the scale of our apparatus is no +longer fitting on a tabletop and also + + align:start position:0% +longer fitting on a tabletop and also + + + align:start position:0% +longer fitting on a tabletop and also +once you need eight to Fifteen billion + + align:start position:0% +once you need eight to Fifteen billion + + + align:start position:0% +once you need eight to Fifteen billion +dollars to do your experiment now you + + align:start position:0% +dollars to do your experiment now you + + + align:start position:0% +dollars to do your experiment now you +have a different place in the world of + + align:start position:0% +have a different place in the world of + + + align:start position:0% +have a different place in the world of +politics and world affairs as well + + align:start position:0% +politics and world affairs as well + + + align:start position:0% +politics and world affairs as well +and likewise the story didn't end + + align:start position:0% +and likewise the story didn't end + + + align:start position:0% +and likewise the story didn't end +thankfully with the cancellation of the + + align:start position:0% +thankfully with the cancellation of the + + + align:start position:0% +thankfully with the cancellation of the +super collider we have a shift to other + + align:start position:0% +super collider we have a shift to other + + + align:start position:0% +super collider we have a shift to other +kinds of still large-scale research for + + align:start position:0% +kinds of still large-scale research for + + + align:start position:0% +kinds of still large-scale research for +example to push to billion dollar + + align:start position:0% +example to push to billion dollar + + + align:start position:0% +example to push to billion dollar +satellites like the plot satellite shown + + align:start position:0% +satellites like the plot satellite shown + + + align:start position:0% +satellites like the plot satellite shown +here uh in its study of the of the very + + align:start position:0% +here uh in its study of the of the very + + + align:start position:0% +here uh in its study of the of the very +earliest moments of the universe so + + align:start position:0% +earliest moments of the universe so + + + align:start position:0% +earliest moments of the universe so +that's in kind of snapshot + + align:start position:0% +that's in kind of snapshot + + + align:start position:0% +that's in kind of snapshot +um kind of uh picture form the kinds of + + align:start position:0% +um kind of uh picture form the kinds of + + + align:start position:0% +um kind of uh picture form the kinds of +terrain that we're going to cover over + + align:start position:0% +terrain that we're going to cover over + + + align:start position:0% +terrain that we're going to cover over +the course of time and I'll say more + + align:start position:0% +the course of time and I'll say more + + + align:start position:0% +the course of time and I'll say more +about that soon but I just want to give + + align:start position:0% +about that soon but I just want to give + + + align:start position:0% +about that soon but I just want to give +you a kind of preview + + align:start position:0% +you a kind of preview + + + align:start position:0% +you a kind of preview +okay let's talk some nuts and bolts for + + align:start position:0% +okay let's talk some nuts and bolts for + + + align:start position:0% +okay let's talk some nuts and bolts for +a little bit + + align:start position:0% +a little bit + + + align:start position:0% +a little bit +this course has no prerequisites as I'm + + align:start position:0% +this course has no prerequisites as I'm + + + align:start position:0% +this course has no prerequisites as I'm +sure you know it's a Communications + + align:start position:0% +sure you know it's a Communications + + + align:start position:0% +sure you know it's a Communications +intensive subject for physics majors and + + align:start position:0% +intensive subject for physics majors and + + + align:start position:0% +intensive subject for physics majors and +course eight but there's no prior + + align:start position:0% +course eight but there's no prior + + + align:start position:0% +course eight but there's no prior +coursework required it's not limited to + + align:start position:0% +coursework required it's not limited to + + + align:start position:0% +coursework required it's not limited to +students in the physics major it's open + + align:start position:0% +students in the physics major it's open + + + align:start position:0% +students in the physics major it's open +to first year Undeclared students and so + + align:start position:0% +to first year Undeclared students and so + + + align:start position:0% +to first year Undeclared students and so +on there's no prereqs our own is our aim + + align:start position:0% +on there's no prereqs our own is our aim + + + align:start position:0% +on there's no prereqs our own is our aim +uh in the course is really to improve + + align:start position:0% +uh in the course is really to improve + + + align:start position:0% +uh in the course is really to improve +written communication skills rather than + + align:start position:0% +written communication skills rather than + + + align:start position:0% +written communication skills rather than +to worry too much about things like + + align:start position:0% +to worry too much about things like + + + align:start position:0% +to worry too much about things like +problem sets or problem solving which + + align:start position:0% +problem sets or problem solving which + + + align:start position:0% +problem sets or problem solving which +are dearly important to me but this + + align:start position:0% +are dearly important to me but this + + + align:start position:0% +are dearly important to me but this +course has has a different kind of + + align:start position:0% +course has has a different kind of + + + align:start position:0% +course has has a different kind of +center of gravity so to speak + + align:start position:0% +center of gravity so to speak + + + align:start position:0% +center of gravity so to speak +I I should say I've had in the years + + align:start position:0% +I I should say I've had in the years + + + align:start position:0% +I I should say I've had in the years +past I've had high school students take + + align:start position:0% +past I've had high school students take + + + align:start position:0% +past I've had high school students take +the course and do very very well really + + align:start position:0% +the course and do very very well really + + + align:start position:0% +the course and do very very well really +really no prerequisites + + align:start position:0% +really no prerequisites + + + align:start position:0% +really no prerequisites +I want to emphasize that I would + + align:start position:0% +I want to emphasize that I would + + + align:start position:0% +I want to emphasize that I would +emphasize that especially because some + + align:start position:0% +emphasize that especially because some + + + align:start position:0% +emphasize that especially because some +of the very first readings for the term + + align:start position:0% +of the very first readings for the term + + + align:start position:0% +of the very first readings for the term +that you'll have even in advance of this + + align:start position:0% +that you'll have even in advance of this + + + align:start position:0% +that you'll have even in advance of this +coming uh next lecture might look pretty + + align:start position:0% +coming uh next lecture might look pretty + + + align:start position:0% +coming uh next lecture might look pretty +technical or pretty off-putting + + align:start position:0% +technical or pretty off-putting + + + align:start position:0% +technical or pretty off-putting +um some not all of them but some of the + + align:start position:0% +um some not all of them but some of the + + + align:start position:0% +um some not all of them but some of the +readings will have lots of equations + + align:start position:0% +readings will have lots of equations + + + align:start position:0% +readings will have lots of equations +that look like would often be taken from + + align:start position:0% +that look like would often be taken from + + + align:start position:0% +that look like would often be taken from +old textbooks might be on topics you + + align:start position:0% +old textbooks might be on topics you + + + align:start position:0% +old textbooks might be on topics you +haven't had a chance to have a different + + align:start position:0% +haven't had a chance to have a different + + + align:start position:0% +haven't had a chance to have a different +formal course and so on and I want to + + align:start position:0% +formal course and so on and I want to + + + align:start position:0% +formal course and so on and I want to +emphasize that's okay if this looks + + align:start position:0% +emphasize that's okay if this looks + + + align:start position:0% +emphasize that's okay if this looks +strange partly it's designed to look + + align:start position:0% +strange partly it's designed to look + + + align:start position:0% +strange partly it's designed to look +strange actually + + align:start position:0% +strange actually + + + align:start position:0% +strange actually +so the strangeness is meant to trigger + + align:start position:0% +so the strangeness is meant to trigger + + + align:start position:0% +so the strangeness is meant to trigger +some questions about what did people + + align:start position:0% +some questions about what did people + + + align:start position:0% +some questions about what did people +think they were doing when they read + + align:start position:0% +think they were doing when they read + + + align:start position:0% +think they were doing when they read +texts like those so if they look either + + align:start position:0% +texts like those so if they look either + + + align:start position:0% +texts like those so if they look either +very hard or unfamiliar or technical + + align:start position:0% +very hard or unfamiliar or technical + + + align:start position:0% +very hard or unfamiliar or technical +that really is kind of part of the point + + align:start position:0% +that really is kind of part of the point + + + align:start position:0% +that really is kind of part of the point +and part of the point for this + + align:start position:0% +and part of the point for this + + + align:start position:0% +and part of the point for this +particular class is not to worry about + + align:start position:0% +particular class is not to worry about + + + align:start position:0% +particular class is not to worry about +reproducing those calculations or + + align:start position:0% +reproducing those calculations or + + + align:start position:0% +reproducing those calculations or +understanding every single step of the + + align:start position:0% +understanding every single step of the + + + align:start position:0% +understanding every single step of the +mathematics I like to joke that my my + + align:start position:0% +mathematics I like to joke that my my + + + align:start position:0% +mathematics I like to joke that my my +very many friends in the physics + + align:start position:0% +very many friends in the physics + + + align:start position:0% +very many friends in the physics +department it's their job to help you + + align:start position:0% +department it's their job to help you + + + align:start position:0% +department it's their job to help you +all learn how to calculate and many of + + align:start position:0% +all learn how to calculate and many of + + + align:start position:0% +all learn how to calculate and many of +you I'm sure calculated very very well + + align:start position:0% +you I'm sure calculated very very well + + + align:start position:0% +you I'm sure calculated very very well +already and that's incredibly important + + align:start position:0% +already and that's incredibly important + + + align:start position:0% +already and that's incredibly important +this class has a different set of goals + + align:start position:0% +this class has a different set of goals + + + align:start position:0% +this class has a different set of goals +and aims and so I want to really + + align:start position:0% +and aims and so I want to really + + + align:start position:0% +and aims and so I want to really +emphasize uh not to be kind of frankly + + align:start position:0% +emphasize uh not to be kind of frankly + + + align:start position:0% +emphasize uh not to be kind of frankly +scared off if some of the readings look + + align:start position:0% +scared off if some of the readings look + + + align:start position:0% +scared off if some of the readings look +at first blush at least a little + + align:start position:0% +at first blush at least a little + + + align:start position:0% +at first blush at least a little +um overwhelming they should look strange + + align:start position:0% +um overwhelming they should look strange + + + align:start position:0% +um overwhelming they should look strange +and if every step in the derivation is + + align:start position:0% +and if every step in the derivation is + + + align:start position:0% +and if every step in the derivation is +not so clear that's okay in this class + + align:start position:0% +not so clear that's okay in this class + + + align:start position:0% +not so clear that's okay in this class +is special so we're going to be focusing + + align:start position:0% +is special so we're going to be focusing + + + align:start position:0% +is special so we're going to be focusing +on a range of ideas in modern physics + + align:start position:0% +on a range of ideas in modern physics + + + align:start position:0% +on a range of ideas in modern physics +and also they're changing context as I + + align:start position:0% +and also they're changing context as I + + + align:start position:0% +and also they're changing context as I +mentioned of many kinds of contexts and + + align:start position:0% +mentioned of many kinds of contexts and + + + align:start position:0% +mentioned of many kinds of contexts and +it's of course always always okay to ask + + align:start position:0% +it's of course always always okay to ask + + + align:start position:0% +it's of course always always okay to ask +for clarifications uh that formalism is + + align:start position:0% +for clarifications uh that formalism is + + + align:start position:0% +for clarifications uh that formalism is +dear to my heart hopefully dear to many + + align:start position:0% +dear to my heart hopefully dear to many + + + align:start position:0% +dear to my heart hopefully dear to many +of yours I'm not saying ignore the + + align:start position:0% +of yours I'm not saying ignore the + + + align:start position:0% +of yours I'm not saying ignore the +equations mathematics I'm just trying to + + align:start position:0% +equations mathematics I'm just trying to + + + align:start position:0% +equations mathematics I'm just trying to +emphasize not to worry about getting + + align:start position:0% +emphasize not to worry about getting + + + align:start position:0% +emphasize not to worry about getting +hung up if especially on the first + + align:start position:0% +hung up if especially on the first + + + align:start position:0% +hung up if especially on the first +reading things look very strange + + align:start position:0% +reading things look very strange + + + align:start position:0% +reading things look very strange +for a bunch of the of the um lectures + + align:start position:0% +for a bunch of the of the um lectures + + + align:start position:0% +for a bunch of the of the um lectures +not for everyone but for a bunch of them + + align:start position:0% +not for everyone but for a bunch of them + + + align:start position:0% +not for everyone but for a bunch of them +I'm actually writing up separate little + + align:start position:0% +I'm actually writing up separate little + + + align:start position:0% +I'm actually writing up separate little +short lecture notes in addition to these + + align:start position:0% +short lecture notes in addition to these + + + align:start position:0% +short lecture notes in addition to these +lecture slides to go through some more + + align:start position:0% +lecture slides to go through some more + + + align:start position:0% +lecture slides to go through some more +intermediate steps and derivations and + + align:start position:0% +intermediate steps and derivations and + + + align:start position:0% +intermediate steps and derivations and +so on those are always going to be + + align:start position:0% +so on those are always going to be + + + align:start position:0% +so on those are always going to be +optional it really is just to help as a + + align:start position:0% +optional it really is just to help as a + + + align:start position:0% +optional it really is just to help as a +kind of additional resource and also + + align:start position:0% +kind of additional resource and also + + + align:start position:0% +kind of additional resource and also +we'll have office hours and you can + + align:start position:0% +we'll have office hours and you can + + + align:start position:0% +we'll have office hours and you can +always make an appointment to meet with + + align:start position:0% +always make an appointment to meet with + + + align:start position:0% +always make an appointment to meet with +me or your teaching assistants uh + + align:start position:0% +me or your teaching assistants uh + + + align:start position:0% +me or your teaching assistants uh +directly so I just want to emphasize uh + + align:start position:0% +directly so I just want to emphasize uh + + + align:start position:0% +directly so I just want to emphasize uh +the aims course we're going to work on + + align:start position:0% +the aims course we're going to work on + + + align:start position:0% +the aims course we're going to work on +on written communication and we'll get + + align:start position:0% +on written communication and we'll get + + + align:start position:0% +on written communication and we'll get +to do it with some I think really juicy + + align:start position:0% +to do it with some I think really juicy + + + align:start position:0% +to do it with some I think really juicy +amazing fun material that's our that's + + align:start position:0% +amazing fun material that's our that's + + + align:start position:0% +amazing fun material that's our that's +our overarching aim for the semester + + align:start position:0% +our overarching aim for the semester + + + align:start position:0% +our overarching aim for the semester +I like to think of this class as a kind + + align:start position:0% +I like to think of this class as a kind + + + align:start position:0% +I like to think of this class as a kind +of road map and it turns out roadmaps + + align:start position:0% +of road map and it turns out roadmaps + + + align:start position:0% +of road map and it turns out roadmaps +work in at least two directions it could + + align:start position:0% +work in at least two directions it could + + + align:start position:0% +work in at least two directions it could +be a map of where you're heading if + + align:start position:0% +be a map of where you're heading if + + + align:start position:0% +be a map of where you're heading if +you're new to MIT you're new to the + + align:start position:0% +you're new to MIT you're new to the + + + align:start position:0% +you're new to MIT you're new to the +physics department or just curious and + + align:start position:0% +physics department or just curious and + + + align:start position:0% +physics department or just curious and +coming in from a different field it can + + align:start position:0% +coming in from a different field it can + + + align:start position:0% +coming in from a different field it can +be a kind of preview of some pretty + + align:start position:0% +be a kind of preview of some pretty + + + align:start position:0% +be a kind of preview of some pretty +awesome cool stuff that could be ahead + + align:start position:0% +awesome cool stuff that could be ahead + + + align:start position:0% +awesome cool stuff that could be ahead +of you it could also be a kind of look + + align:start position:0% +of you it could also be a kind of look + + + align:start position:0% +of you it could also be a kind of look +in the rear view mirror for Junior's + + align:start position:0% +in the rear view mirror for Junior's + + + align:start position:0% +in the rear view mirror for Junior's +estate or seniors in the physics + + align:start position:0% +estate or seniors in the physics + + + align:start position:0% +estate or seniors in the physics +department you will have seen some of + + align:start position:0% +department you will have seen some of + + + align:start position:0% +department you will have seen some of +this material in other courses already + + align:start position:0% +this material in other courses already + + + align:start position:0% +this material in other courses already +but this is a chance to begin kind of + + align:start position:0% +but this is a chance to begin kind of + + + align:start position:0% +but this is a chance to begin kind of +seeing perhaps how different pieces fit + + align:start position:0% +seeing perhaps how different pieces fit + + + align:start position:0% +seeing perhaps how different pieces fit +together to kind of synthesize a map of + + align:start position:0% +together to kind of synthesize a map of + + + align:start position:0% +together to kind of synthesize a map of +what might have been kind of separated + + align:start position:0% +what might have been kind of separated + + + align:start position:0% +what might have been kind of separated +or disparate Parts until now so I like + + align:start position:0% +or disparate Parts until now so I like + + + align:start position:0% +or disparate Parts until now so I like +this idea of a road map either whether + + align:start position:0% +this idea of a road map either whether + + + align:start position:0% +this idea of a road map either whether +you're whether you're starting a journey + + align:start position:0% +you're whether you're starting a journey + + + align:start position:0% +you're whether you're starting a journey +or looking back uh how you got to where + + align:start position:0% +or looking back uh how you got to where + + + align:start position:0% +or looking back uh how you got to where +you are now hopefully this course will + + align:start position:0% +you are now hopefully this course will + + + align:start position:0% +you are now hopefully this course will +help with some of that as well + + align:start position:0% +help with some of that as well + + + align:start position:0% +help with some of that as well +okay so let me pause and ask for any + + align:start position:0% +okay so let me pause and ask for any + + + align:start position:0% +okay so let me pause and ask for any +questions if you do have questions + + align:start position:0% +questions if you do have questions + + + align:start position:0% +questions if you do have questions +please try to raise your your blue hand + + align:start position:0% +please try to raise your your blue hand + + + align:start position:0% +please try to raise your your blue hand +and ask the teaching assistants who are + + align:start position:0% +and ask the teaching assistants who are + + + align:start position:0% +and ask the teaching assistants who are +co-hosts of this Zoom session uh to to + + align:start position:0% +co-hosts of this Zoom session uh to to + + + align:start position:0% +co-hosts of this Zoom session uh to to +kind of recognize you and then they can + + align:start position:0% +kind of recognize you and then they can + + + align:start position:0% +kind of recognize you and then they can +uh ask you to unmute yourself any + + align:start position:0% +uh ask you to unmute yourself any + + + align:start position:0% +uh ask you to unmute yourself any +questions so far + + align:start position:0% + + + + align:start position:0% + +I hear a resounding silence uh so I'm + + align:start position:0% +I hear a resounding silence uh so I'm + + + align:start position:0% +I hear a resounding silence uh so I'm +gonna I'm gonna charge ahead but if you + + align:start position:0% +gonna I'm gonna charge ahead but if you + + + align:start position:0% +gonna I'm gonna charge ahead but if you +do have questions again please feel free + + align:start position:0% +do have questions again please feel free + + + align:start position:0% +do have questions again please feel free +to use the chat or the or the blue hand + + align:start position:0% +to use the chat or the or the blue hand + + + align:start position:0% +to use the chat or the or the blue hand +uh raise hand icon + + align:start position:0% +uh raise hand icon + + + align:start position:0% +uh raise hand icon +foreign + + align:start position:0% +foreign + + + align:start position:0% +foreign +okay so for this part sorry I want to + + align:start position:0% +okay so for this part sorry I want to + + + align:start position:0% +okay so for this part sorry I want to +just take a few moments and introduce + + align:start position:0% +just take a few moments and introduce + + + align:start position:0% +just take a few moments and introduce +um the the whole team I'm very excited + + align:start position:0% +um the the whole team I'm very excited + + + align:start position:0% +um the the whole team I'm very excited +to work with uh I think a really + + align:start position:0% +to work with uh I think a really + + + align:start position:0% +to work with uh I think a really +terrific team uh of instructors for this + + align:start position:0% +terrific team uh of instructors for this + + + align:start position:0% +terrific team uh of instructors for this +class it's a big group we have uh four + + align:start position:0% +class it's a big group we have uh four + + + align:start position:0% +class it's a big group we have uh four +teaching assistants in addition to + + align:start position:0% +teaching assistants in addition to + + + align:start position:0% +teaching assistants in addition to +myself so I'll just say a little bit + + align:start position:0% +myself so I'll just say a little bit + + + align:start position:0% +myself so I'll just say a little bit +about my own um research uh I am a + + align:start position:0% +about my own um research uh I am a + + + align:start position:0% +about my own um research uh I am a +professor at MIT I teach both in our + + align:start position:0% +professor at MIT I teach both in our + + + align:start position:0% +professor at MIT I teach both in our +program in science technology and + + align:start position:0% +program in science technology and + + + align:start position:0% +program in science technology and +Society STS in that department I uh + + align:start position:0% +Society STS in that department I uh + + + align:start position:0% +Society STS in that department I uh +conduct research and work with students + + align:start position:0% +conduct research and work with students + + + align:start position:0% +conduct research and work with students +uh in the history of Science and + + align:start position:0% +uh in the history of Science and + + + align:start position:0% +uh in the history of Science and +particular history of modern physics + + align:start position:0% +particular history of modern physics + + + align:start position:0% +particular history of modern physics +I've written a few books I've edited + + align:start position:0% +I've written a few books I've edited + + + align:start position:0% +I've written a few books I've edited +other books a lot of the material that + + align:start position:0% +other books a lot of the material that + + + align:start position:0% +other books a lot of the material that +we'll cover in this semester on this + + align:start position:0% +we'll cover in this semester on this + + + align:start position:0% +we'll cover in this semester on this +term comes not surprisingly from things + + align:start position:0% +term comes not surprisingly from things + + + align:start position:0% +term comes not surprisingly from things +that I have a particular interest in + + align:start position:0% +that I have a particular interest in + + + align:start position:0% +that I have a particular interest in +I've written about or who are very dear + + align:start position:0% +I've written about or who are very dear + + + align:start position:0% +I've written about or who are very dear +friends of mine have written about so + + align:start position:0% +friends of mine have written about so + + + align:start position:0% +friends of mine have written about so +I'm sort of uh I like I'm very lucky to + + align:start position:0% +I'm sort of uh I like I'm very lucky to + + + align:start position:0% +I'm sort of uh I like I'm very lucky to +get to be immersed in the history of + + align:start position:0% +get to be immersed in the history of + + + align:start position:0% +get to be immersed in the history of +modern science uh when I wear my STS cap + + align:start position:0% +modern science uh when I wear my STS cap + + + align:start position:0% +modern science uh when I wear my STS cap +I'm also a member of the physics + + align:start position:0% +I'm also a member of the physics + + + align:start position:0% +I'm also a member of the physics +department Professor physics uh up here + + align:start position:0% +department Professor physics uh up here + + + align:start position:0% +department Professor physics uh up here +I have a picture of my research group + + align:start position:0% +I have a picture of my research group + + + align:start position:0% +I have a picture of my research group +there's actually somewhat old photo you + + align:start position:0% +there's actually somewhat old photo you + + + align:start position:0% +there's actually somewhat old photo you +probably won't recognize the faces + + align:start position:0% +probably won't recognize the faces + + + align:start position:0% +probably won't recognize the faces +because even the Europe students in this + + align:start position:0% +because even the Europe students in this + + + align:start position:0% +because even the Europe students in this +photo have all graduated by now I work + + align:start position:0% +photo have all graduated by now I work + + + align:start position:0% +photo have all graduated by now I work +very closely with Alan Guth in our + + align:start position:0% +very closely with Alan Guth in our + + + align:start position:0% +very closely with Alan Guth in our +Center for theoretical physics within + + align:start position:0% +Center for theoretical physics within + + + align:start position:0% +Center for theoretical physics within +the department uh we work on many + + align:start position:0% +the department uh we work on many + + + align:start position:0% +the department uh we work on many +aspects of early Universe cosmology uh + + align:start position:0% +aspects of early Universe cosmology uh + + + align:start position:0% +aspects of early Universe cosmology uh +we'll actually come to some of those + + align:start position:0% +we'll actually come to some of those + + + align:start position:0% +we'll actually come to some of those +topics near the end of this semester + + align:start position:0% +topics near the end of this semester + + + align:start position:0% +topics near the end of this semester +because I couldn't resist I love it so + + align:start position:0% +because I couldn't resist I love it so + + + align:start position:0% +because I couldn't resist I love it so +much I've also I've been working for a + + align:start position:0% +much I've also I've been working for a + + + align:start position:0% +much I've also I've been working for a +number of years on foundations of + + align:start position:0% +number of years on foundations of + + + align:start position:0% +number of years on foundations of +quantum theory including new + + align:start position:0% +quantum theory including new + + + align:start position:0% +quantum theory including new +experimental tests of topics like + + align:start position:0% +experimental tests of topics like + + + align:start position:0% +experimental tests of topics like +quantum entanglement we'll talk about + + align:start position:0% +quantum entanglement we'll talk about + + + align:start position:0% +quantum entanglement we'll talk about +some of that this semester as well so on + + align:start position:0% +some of that this semester as well so on + + + align:start position:0% +some of that this semester as well so on +the physics side I + + align:start position:0% +the physics side I + + + align:start position:0% +the physics side I +especially interested in theoretical + + align:start position:0% +especially interested in theoretical + + + align:start position:0% +especially interested in theoretical +early Universe cosmology and + + align:start position:0% +early Universe cosmology and + + + align:start position:0% +early Universe cosmology and +astrophysics and also uh various aspects + + align:start position:0% +astrophysics and also uh various aspects + + + align:start position:0% +astrophysics and also uh various aspects +of quantum theory and even some uh + + align:start position:0% +of quantum theory and even some uh + + + align:start position:0% +of quantum theory and even some uh +interesting new recent work on Quantum + + align:start position:0% +interesting new recent work on Quantum + + + align:start position:0% +interesting new recent work on Quantum +information science so that's uh that's + + align:start position:0% +information science so that's uh that's + + + align:start position:0% +information science so that's uh that's +where I'm coming from + + align:start position:0% +where I'm coming from + + + align:start position:0% +where I'm coming from +now let's get to uh what are you gonna + + align:start position:0% +now let's get to uh what are you gonna + + + align:start position:0% +now let's get to uh what are you gonna +do in this class what the one things + + align:start position:0% +do in this class what the one things + + + align:start position:0% +do in this class what the one things +you're going to do is read not a ton + + align:start position:0% +you're going to do is read not a ton + + + align:start position:0% +you're going to do is read not a ton +we've worked very carefully to make the + + align:start position:0% +we've worked very carefully to make the + + + align:start position:0% +we've worked very carefully to make the +reading list we think really kind of + + align:start position:0% +reading list we think really kind of + + + align:start position:0% +reading list we think really kind of +curated and uh and not overwhelm + + align:start position:0% +curated and uh and not overwhelm + + + align:start position:0% +curated and uh and not overwhelm +students with with a large page count + + align:start position:0% +students with with a large page count + + + align:start position:0% +students with with a large page count +and so the best thing you can do is read + + align:start position:0% +and so the best thing you can do is read + + + align:start position:0% +and so the best thing you can do is read +the genuine January generally rather + + align:start position:0% +the genuine January generally rather + + + align:start position:0% +the genuine January generally rather +brief reading assignments in advance of + + align:start position:0% +brief reading assignments in advance of + + + align:start position:0% +brief reading assignments in advance of +the of the class with which they're + + align:start position:0% +the of the class with which they're + + + align:start position:0% +the of the class with which they're +Associated it'll help if you've been + + align:start position:0% +Associated it'll help if you've been + + + align:start position:0% +Associated it'll help if you've been +able to do the readings ahead of the + + align:start position:0% +able to do the readings ahead of the + + + align:start position:0% +able to do the readings ahead of the +class session + + align:start position:0% +class session + + + align:start position:0% +class session +what are the actual subject requirements + + align:start position:0% +what are the actual subject requirements + + + align:start position:0% +what are the actual subject requirements +in addition to keeping up the reading as + + align:start position:0% +in addition to keeping up the reading as + + + align:start position:0% +in addition to keeping up the reading as +I mentioned this is a CI course for uh + + align:start position:0% +I mentioned this is a CI course for uh + + + align:start position:0% +I mentioned this is a CI course for uh +for physics Majors so our main emphasis + + align:start position:0% +for physics Majors so our main emphasis + + + align:start position:0% +for physics Majors so our main emphasis +is on written communication it will not + + align:start position:0% +is on written communication it will not + + + align:start position:0% +is on written communication it will not +be on oral communication partly because + + align:start position:0% +be on oral communication partly because + + + align:start position:0% +be on oral communication partly because +there's a hundred of us by Zoo so it + + align:start position:0% +there's a hundred of us by Zoo so it + + + align:start position:0% +there's a hundred of us by Zoo so it +really will be on written communication + + align:start position:0% +really will be on written communication + + + align:start position:0% +really will be on written communication +which had always been the overwhelming + + align:start position:0% +which had always been the overwhelming + + + align:start position:0% +which had always been the overwhelming +majority of the course structure even in + + align:start position:0% +majority of the course structure even in + + + align:start position:0% +majority of the course structure even in +previous years + + align:start position:0% +previous years + + + align:start position:0% +previous years +so like nearly all CI courses we have + + align:start position:0% +so like nearly all CI courses we have + + + align:start position:0% +so like nearly all CI courses we have +um a number of pages of writing over the + + align:start position:0% +um a number of pages of writing over the + + + align:start position:0% +um a number of pages of writing over the +course of the semester the way we do it + + align:start position:0% +course of the semester the way we do it + + + align:start position:0% +course of the semester the way we do it +in this term is to break it up into a + + align:start position:0% +in this term is to break it up into a + + + align:start position:0% +in this term is to break it up into a +number of assignments that kind of build + + align:start position:0% +number of assignments that kind of build + + + align:start position:0% +number of assignments that kind of build +up they build both in length but also in + + align:start position:0% +up they build both in length but also in + + + align:start position:0% +up they build both in length but also in +the nature of the assignment in the type + + align:start position:0% +the nature of the assignment in the type + + + align:start position:0% +the nature of the assignment in the type +of writing that we'll be working on and + + align:start position:0% +of writing that we'll be working on and + + + align:start position:0% +of writing that we'll be working on and +the nature of say the kinds of sources + + align:start position:0% +the nature of say the kinds of sources + + + align:start position:0% +the nature of say the kinds of sources +we'll be working with or the nature the + + align:start position:0% +we'll be working with or the nature the + + + align:start position:0% +we'll be working with or the nature the +argument we want to be able to + + align:start position:0% +argument we want to be able to + + + align:start position:0% +argument we want to be able to +articulate and these really quite + + align:start position:0% +articulate and these really quite + + + align:start position:0% +articulate and these really quite +amazing teaching assistants are here to + + align:start position:0% +amazing teaching assistants are here to + + + align:start position:0% +amazing teaching assistants are here to +work very closely with you on each of + + align:start position:0% +work very closely with you on each of + + + align:start position:0% +work very closely with you on each of +these papers so we're not going to + + align:start position:0% +these papers so we're not going to + + + align:start position:0% +these papers so we're not going to +expect you to do it uh every step on + + align:start position:0% +expect you to do it uh every step on + + + align:start position:0% +expect you to do it uh every step on +your own so you can see now the due + + align:start position:0% +your own so you can see now the due + + + align:start position:0% +your own so you can see now the due +dates uh the structure the first bit + + align:start position:0% +dates uh the structure the first bit + + + align:start position:0% +dates uh the structure the first bit +will of course we'll hand out the + + align:start position:0% +will of course we'll hand out the + + + align:start position:0% +will of course we'll hand out the +assignments uh well in advance of each + + align:start position:0% +assignments uh well in advance of each + + + align:start position:0% +assignments uh well in advance of each +of the due dates uh the actual kind of + + align:start position:0% +of the due dates uh the actual kind of + + + align:start position:0% +of the due dates uh the actual kind of +prompt + + align:start position:0% +prompt + + + align:start position:0% +prompt +so pretty soon we'll finalize a prompt + + align:start position:0% +so pretty soon we'll finalize a prompt + + + align:start position:0% +so pretty soon we'll finalize a prompt +for paper one we'll make sure it's easy + + align:start position:0% +for paper one we'll make sure it's easy + + + align:start position:0% +for paper one we'll make sure it's easy +for you to find on the canvas site that + + align:start position:0% +for you to find on the canvas site that + + + align:start position:0% +for you to find on the canvas site that +one will be four or five double spaced + + align:start position:0% +one will be four or five double spaced + + + align:start position:0% +one will be four or five double spaced +Pages really a handful of paragraphs not + + align:start position:0% +Pages really a handful of paragraphs not + + + align:start position:0% +Pages really a handful of paragraphs not +a very long essay that'll be due um + + align:start position:0% +a very long essay that'll be due um + + + align:start position:0% +a very long essay that'll be due um +electronically uh near the end of + + align:start position:0% +electronically uh near the end of + + + align:start position:0% +electronically uh near the end of +September the second paper we do a + + align:start position:0% +September the second paper we do a + + + align:start position:0% +September the second paper we do a +couple weeks after that a little bit + + align:start position:0% +couple weeks after that a little bit + + + align:start position:0% +couple weeks after that a little bit +longer six or seven doubles for these + + align:start position:0% +longer six or seven doubles for these + + + align:start position:0% +longer six or seven doubles for these +pages and a little more complicated a + + align:start position:0% +pages and a little more complicated a + + + align:start position:0% +pages and a little more complicated a +range of types of sources to to uh to to + + align:start position:0% +range of types of sources to to uh to to + + + align:start position:0% +range of types of sources to to uh to to +make use of as you build your argument + + align:start position:0% +make use of as you build your argument + + + align:start position:0% +make use of as you build your argument +because it's a CI course like usual + + align:start position:0% +because it's a CI course like usual + + + align:start position:0% +because it's a CI course like usual +we'll have a mandatory rewrite of that + + align:start position:0% +we'll have a mandatory rewrite of that + + + align:start position:0% +we'll have a mandatory rewrite of that +paper to assignment + + align:start position:0% +paper to assignment + + + align:start position:0% +paper to assignment +that'll be due handed in separately + + align:start position:0% +that'll be due handed in separately + + + align:start position:0% +that'll be due handed in separately +several weeks after the first iteration + + align:start position:0% +several weeks after the first iteration + + + align:start position:0% +several weeks after the first iteration +and then finally the the final paper is + + align:start position:0% +and then finally the the final paper is + + + align:start position:0% +and then finally the the final paper is +due on the last day of classes uh + + align:start position:0% +due on the last day of classes uh + + + align:start position:0% +due on the last day of classes uh +December 9th so please note there is no + + align:start position:0% +December 9th so please note there is no + + + align:start position:0% +December 9th so please note there is no +midterm there are no problem sets + + align:start position:0% +midterm there are no problem sets + + + align:start position:0% +midterm there are no problem sets +there's no final exam the student work + + align:start position:0% +there's no final exam the student work + + + align:start position:0% +there's no final exam the student work +you'll be handed in will be exclusively + + align:start position:0% +you'll be handed in will be exclusively + + + align:start position:0% +you'll be handed in will be exclusively +these essays the series of essays and + + align:start position:0% +these essays the series of essays and + + + align:start position:0% +these essays the series of essays and +again we'll be working with you along + + align:start position:0% +again we'll be working with you along + + + align:start position:0% +again we'll be working with you along +the way + + align:start position:0% +the way + + + align:start position:0% +the way +you can see the kind of distribution uh + + align:start position:0% +you can see the kind of distribution uh + + + align:start position:0% +you can see the kind of distribution uh +here about how the different papers + + align:start position:0% +here about how the different papers + + + align:start position:0% +here about how the different papers +contribute to your overall final course + + align:start position:0% +contribute to your overall final course + + + align:start position:0% +contribute to your overall final course +grade obviously if any questions come up + + align:start position:0% +grade obviously if any questions come up + + + align:start position:0% +grade obviously if any questions come up +along the way of course of course please + + align:start position:0% +along the way of course of course please + + + align:start position:0% +along the way of course of course please +don't hesitate uh to ask me about it or + + align:start position:0% +don't hesitate uh to ask me about it or + + + align:start position:0% +don't hesitate uh to ask me about it or +your teaching assistant that's the sort + + align:start position:0% +your teaching assistant that's the sort + + + align:start position:0% +your teaching assistant that's the sort +of stuff you'll be working on uh + + align:start position:0% +of stuff you'll be working on uh + + + align:start position:0% +of stuff you'll be working on uh +concretely over the course of the term + + align:start position:0% +concretely over the course of the term + + + align:start position:0% +concretely over the course of the term +so again I'll pause any questions on any + + align:start position:0% +so again I'll pause any questions on any + + + align:start position:0% +so again I'll pause any questions on any +of of those items + + align:start position:0% + + + + align:start position:0% + +so far so good + + align:start position:0% +so far so good + + + align:start position:0% +so far so good +and so good so so uh Saba asked a + + align:start position:0% +and so good so so uh Saba asked a + + + align:start position:0% +and so good so so uh Saba asked a +question there's zero difference uh for + + align:start position:0% +question there's zero difference uh for + + + align:start position:0% +question there's zero difference uh for +the mechanics of the course between + + align:start position:0% +the mechanics of the course between + + + align:start position:0% +the mechanics of the course between +grading or homework or content between + + align:start position:0% +grading or homework or content between + + + align:start position:0% +grading or homework or content between +SDS and and Corset version it is + + align:start position:0% +SDS and and Corset version it is + + + align:start position:0% +SDS and and Corset version it is +literally one class it's just jointly + + align:start position:0% +literally one class it's just jointly + + + align:start position:0% +literally one class it's just jointly +listed and in fact I don't even know I + + align:start position:0% +listed and in fact I don't even know I + + + align:start position:0% +listed and in fact I don't even know I +mean like I'd have it would take work + + align:start position:0% +mean like I'd have it would take work + + + align:start position:0% +mean like I'd have it would take work +for me to figure out which version of + + align:start position:0% +for me to figure out which version of + + + align:start position:0% +for me to figure out which version of +given students actually registered in we + + align:start position:0% +given students actually registered in we + + + align:start position:0% +given students actually registered in we +we just we treated as one class as one + + align:start position:0% +we just we treated as one class as one + + + align:start position:0% +we just we treated as one class as one +set of materials one set of course aims + + align:start position:0% +set of materials one set of course aims + + + align:start position:0% +set of materials one set of course aims +so as far as we're concerned sort of on + + align:start position:0% +so as far as we're concerned sort of on + + + align:start position:0% +so as far as we're concerned sort of on +this shared screen it's one class we're + + align:start position:0% +this shared screen it's one class we're + + + align:start position:0% +this shared screen it's one class we're +going to work on this cool stuff + + align:start position:0% +going to work on this cool stuff + + + align:start position:0% +going to work on this cool stuff +together the tricky part gets you know + + align:start position:0% +together the tricky part gets you know + + + align:start position:0% +together the tricky part gets you know +how to out of the different + + align:start position:0% +how to out of the different + + + align:start position:0% +how to out of the different +um uh kind of uh requirements get it get + + align:start position:0% +um uh kind of uh requirements get it get + + + align:start position:0% +um uh kind of uh requirements get it get +get counted um for different kinds of + + align:start position:0% +get counted um for different kinds of + + + align:start position:0% +get counted um for different kinds of +students but it's one class one one set + + align:start position:0% +students but it's one class one one set + + + align:start position:0% +students but it's one class one one set +of aims one set of materials + + align:start position:0% +of aims one set of materials + + + align:start position:0% +of aims one set of materials +any other questions on this is all + + align:start position:0% +any other questions on this is all + + + align:start position:0% +any other questions on this is all +excellent questions + + align:start position:0% +excellent questions + + + align:start position:0% +excellent questions +yes definitely flood Sean's inbox I see + + align:start position:0% +yes definitely flood Sean's inbox I see + + + align:start position:0% +yes definitely flood Sean's inbox I see +Sean someone helpfully put Sean's um uh + + align:start position:0% +Sean someone helpfully put Sean's um uh + + + align:start position:0% +Sean someone helpfully put Sean's um uh +email address in there + + align:start position:0% +email address in there + + + align:start position:0% +email address in there +okay I'm gonna I'm gonna move on if you + + align:start position:0% +okay I'm gonna I'm gonna move on if you + + + align:start position:0% +okay I'm gonna I'm gonna move on if you +have more questions again please keep + + align:start position:0% +have more questions again please keep + + + align:start position:0% +have more questions again please keep +chiming in but I think I'll go back to + + align:start position:0% +chiming in but I think I'll go back to + + + align:start position:0% +chiming in but I think I'll go back to +uh screen sharing those are excellent + + align:start position:0% +uh screen sharing those are excellent + + + align:start position:0% +uh screen sharing those are excellent +good questions to get us going + + align:start position:0% +good questions to get us going + + + align:start position:0% +good questions to get us going +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so hopefully you can see my screen again + + align:start position:0% +so hopefully you can see my screen again + + + align:start position:0% +so hopefully you can see my screen again +so last part again I won't take too too + + align:start position:0% +so last part again I won't take too too + + + align:start position:0% +so last part again I won't take too too +long we'll finish up early today + + align:start position:0% +long we'll finish up early today + + + align:start position:0% +long we'll finish up early today +I just want to tell you a little bit + + align:start position:0% +I just want to tell you a little bit + + + align:start position:0% +I just want to tell you a little bit +more about the kinds of material that + + align:start position:0% +more about the kinds of material that + + + align:start position:0% +more about the kinds of material that +we'll get to really kind of um kind of + + align:start position:0% +we'll get to really kind of um kind of + + + align:start position:0% +we'll get to really kind of um kind of +chew on get to really explore uh over + + align:start position:0% +chew on get to really explore uh over + + + align:start position:0% +chew on get to really explore uh over +the coming weeks so we'll be starting + + align:start position:0% +the coming weeks so we'll be starting + + + align:start position:0% +the coming weeks so we'll be starting +with a 19th century Legacy in fact + + align:start position:0% +with a 19th century Legacy in fact + + + align:start position:0% +with a 19th century Legacy in fact +starting fairly early in the 19th + + align:start position:0% +starting fairly early in the 19th + + + align:start position:0% +starting fairly early in the 19th +century going back to the 1820s and 30s + + align:start position:0% +century going back to the 1820s and 30s + + + align:start position:0% +century going back to the 1820s and 30s +not for too long we'll kind of gallop + + align:start position:0% +not for too long we'll kind of gallop + + + align:start position:0% +not for too long we'll kind of gallop +forward in time pretty quickly but the + + align:start position:0% +forward in time pretty quickly but the + + + align:start position:0% +forward in time pretty quickly but the +main question We'll be asking that unit + + align:start position:0% +main question We'll be asking that unit + + + align:start position:0% +main question We'll be asking that unit +is what did people think the world was + + align:start position:0% +is what did people think the world was + + + align:start position:0% +is what did people think the world was +made of what did they think it was their + + align:start position:0% +made of what did they think it was their + + + align:start position:0% +made of what did they think it was their +job to study and what what counted as a + + align:start position:0% +job to study and what what counted as a + + + align:start position:0% +job to study and what what counted as a +compelling explanation and equally + + align:start position:0% +compelling explanation and equally + + + align:start position:0% +compelling explanation and equally +interesting I think or equally important + + align:start position:0% +interesting I think or equally important + + + align:start position:0% +interesting I think or equally important +who are the kinds of people who did that + + align:start position:0% +who are the kinds of people who did that + + + align:start position:0% +who are the kinds of people who did that +and where do they do it and what kinds + + align:start position:0% +and where do they do it and what kinds + + + align:start position:0% +and where do they do it and what kinds +of settings or institutions how do they + + align:start position:0% +of settings or institutions how do they + + + align:start position:0% +of settings or institutions how do they +work together what they think their job + + align:start position:0% +work together what they think their job + + + align:start position:0% +work together what they think their job +was + + align:start position:0% + + + + align:start position:0% + +so if all the many topics we could focus + + align:start position:0% +so if all the many topics we could focus + + + align:start position:0% +so if all the many topics we could focus +on Within + + align:start position:0% +on Within + + + align:start position:0% +on Within +the study of uh the Natural Sciences of + + align:start position:0% +the study of uh the Natural Sciences of + + + align:start position:0% +the study of uh the Natural Sciences of +physical sciences in the 19th century + + align:start position:0% +physical sciences in the 19th century + + + align:start position:0% +physical sciences in the 19th century +we're going to look fairly narrowly at + + align:start position:0% +we're going to look fairly narrowly at + + + align:start position:0% +we're going to look fairly narrowly at +examples from electricity and magnetism + + align:start position:0% +examples from electricity and magnetism + + + align:start position:0% +examples from electricity and magnetism +and Optics partly because that becomes + + align:start position:0% +and Optics partly because that becomes + + + align:start position:0% +and Optics partly because that becomes +super important for things like + + align:start position:0% +super important for things like + + + align:start position:0% +super important for things like +relativity and we do want to get too + + align:start position:0% +relativity and we do want to get too + + + align:start position:0% +relativity and we do want to get too +fairly quickly + + align:start position:0% +fairly quickly + + + align:start position:0% +fairly quickly +uh and also because I think they're just + + align:start position:0% +uh and also because I think they're just + + + align:start position:0% +uh and also because I think they're just +fascinating uh in their own right so + + align:start position:0% +fascinating uh in their own right so + + + align:start position:0% +fascinating uh in their own right so +we'll be talking about some names and + + align:start position:0% +we'll be talking about some names and + + + align:start position:0% +we'll be talking about some names and +some some ideas that again are likely + + align:start position:0% +some some ideas that again are likely + + + align:start position:0% +some some ideas that again are likely +familiar to many of you we'll start with + + align:start position:0% +familiar to many of you we'll start with + + + align:start position:0% +familiar to many of you we'll start with +some discussions of of Michael Faraday + + align:start position:0% +some discussions of of Michael Faraday + + + align:start position:0% +some discussions of of Michael Faraday +and his ideas about lines of force and + + align:start position:0% +and his ideas about lines of force and + + + align:start position:0% +and his ideas about lines of force and +The luminiferous Ether will spend a long + + align:start position:0% +The luminiferous Ether will spend a long + + + align:start position:0% +The luminiferous Ether will spend a long +time talking about The Ether we'll talk + + align:start position:0% +time talking about The Ether we'll talk + + + align:start position:0% +time talking about The Ether we'll talk +about James Clark Maxwell you can read a + + align:start position:0% +about James Clark Maxwell you can read a + + + align:start position:0% +about James Clark Maxwell you can read a +short excerpt from uh from his famous + + align:start position:0% +short excerpt from uh from his famous + + + align:start position:0% +short excerpt from uh from his famous +Treatise on electricity magnetism I'm + + align:start position:0% +Treatise on electricity magnetism I'm + + + align:start position:0% +Treatise on electricity magnetism I'm +talking about William Thompson later + + align:start position:0% +talking about William Thompson later + + + align:start position:0% +talking about William Thompson later +known as Lord Calvin and others we'll + + align:start position:0% +known as Lord Calvin and others we'll + + + align:start position:0% +known as Lord Calvin and others we'll +also talk about + + align:start position:0% +also talk about + + + align:start position:0% +also talk about +how do those folks get into their line + + align:start position:0% +how do those folks get into their line + + + align:start position:0% +how do those folks get into their line +of work especially the generation of + + align:start position:0% +of work especially the generation of + + + align:start position:0% +of work especially the generation of +Maxwell Thompson and some of their own + + align:start position:0% +Maxwell Thompson and some of their own + + + align:start position:0% +Maxwell Thompson and some of their own +uh colleagues so what was it like to + + align:start position:0% +uh colleagues so what was it like to + + + align:start position:0% +uh colleagues so what was it like to +become a young uh say mathematical + + align:start position:0% +become a young uh say mathematical + + + align:start position:0% +become a young uh say mathematical +physicist or eventually theoretical + + align:start position:0% +physicist or eventually theoretical + + + align:start position:0% +physicist or eventually theoretical +physicist during the second half of the + + align:start position:0% +physicist during the second half of the + + + align:start position:0% +physicist during the second half of the +19th century how they do that where why + + align:start position:0% +19th century how they do that where why + + + align:start position:0% +19th century how they do that where why +according to whose criteria another + + align:start position:0% +according to whose criteria another + + + align:start position:0% +according to whose criteria another +thing I want to really emphasize this + + align:start position:0% +thing I want to really emphasize this + + + align:start position:0% +thing I want to really emphasize this +one I find incredibly fun is that many + + align:start position:0% +one I find incredibly fun is that many + + + align:start position:0% +one I find incredibly fun is that many +who probably own Master's equations on a + + align:start position:0% +who probably own Master's equations on a + + + align:start position:0% +who probably own Master's equations on a +t-shirt always in fashion we still use + + align:start position:0% +t-shirt always in fashion we still use + + + align:start position:0% +t-shirt always in fashion we still use +Maxwell's equations there are so-called + + align:start position:0% +Maxwell's equations there are so-called + + + align:start position:0% +Maxwell's equations there are so-called +his equations but what I want to sit + + align:start position:0% +his equations but what I want to sit + + + align:start position:0% +his equations but what I want to sit +with for the first few classes is how + + align:start position:0% +with for the first few classes is how + + + align:start position:0% +with for the first few classes is how +remarkably different Maxwell and his + + align:start position:0% +remarkably different Maxwell and his + + + align:start position:0% +remarkably different Maxwell and his +contemporaries interpreted those very + + align:start position:0% +contemporaries interpreted those very + + + align:start position:0% +contemporaries interpreted those very +same mathematical symbols so we still + + align:start position:0% +same mathematical symbols so we still + + + align:start position:0% +same mathematical symbols so we still +put his equations on our t-shirts so to + + align:start position:0% +put his equations on our t-shirts so to + + + align:start position:0% +put his equations on our t-shirts so to +speak + + align:start position:0% +speak + + + align:start position:0% +speak +yeah what we think they mean or what we + + align:start position:0% +yeah what we think they mean or what we + + + align:start position:0% +yeah what we think they mean or what we +think they're good for what we think + + align:start position:0% +think they're good for what we think + + + align:start position:0% +think they're good for what we think +they're talking about what they tell us + + align:start position:0% +they're talking about what they tell us + + + align:start position:0% +they're talking about what they tell us +about the world is almost exactly + + align:start position:0% +about the world is almost exactly + + + align:start position:0% +about the world is almost exactly +opposite to how Maxwell himself imagined + + align:start position:0% +opposite to how Maxwell himself imagined + + + align:start position:0% +opposite to how Maxwell himself imagined +them or how generations of maxwellians + + align:start position:0% +them or how generations of maxwellians + + + align:start position:0% +them or how generations of maxwellians +treated them so we have this kind of + + align:start position:0% +treated them so we have this kind of + + + align:start position:0% +treated them so we have this kind of +continuity in some instances in the in + + align:start position:0% +continuity in some instances in the in + + + align:start position:0% +continuity in some instances in the in +the equations we use sometimes even the + + align:start position:0% +the equations we use sometimes even the + + + align:start position:0% +the equations we use sometimes even the +t-shirts we wear and yet what we think + + align:start position:0% +t-shirts we wear and yet what we think + + + align:start position:0% +t-shirts we wear and yet what we think +those equations or those ideas tell us + + align:start position:0% +those equations or those ideas tell us + + + align:start position:0% +those equations or those ideas tell us +about the world those actually have been + + align:start position:0% +about the world those actually have been + + + align:start position:0% +about the world those actually have been +anything but static or constant over + + align:start position:0% +anything but static or constant over + + + align:start position:0% +anything but static or constant over +time I find that just mind-boggling to + + align:start position:0% +time I find that just mind-boggling to + + + align:start position:0% +time I find that just mind-boggling to +be honest I love that we're going to + + align:start position:0% +be honest I love that we're going to + + + align:start position:0% +be honest I love that we're going to +have a bunch of examples of that + + align:start position:0% +have a bunch of examples of that + + + align:start position:0% +have a bunch of examples of that +throughout this whole semester and one + + align:start position:0% +throughout this whole semester and one + + + align:start position:0% +throughout this whole semester and one +of the first kind of Juicy ones we get + + align:start position:0% +of the first kind of Juicy ones we get + + + align:start position:0% +of the first kind of Juicy ones we get +is with Maxwell's equations so we'll sit + + align:start position:0% +is with Maxwell's equations so we'll sit + + + align:start position:0% +is with Maxwell's equations so we'll sit +with Maxwell and electromagnetism for + + align:start position:0% +with Maxwell and electromagnetism for + + + align:start position:0% +with Maxwell and electromagnetism for +the first couple of lectures the first + + align:start position:0% +the first couple of lectures the first + + + align:start position:0% +the first couple of lectures the first +few few sessions + + align:start position:0% +few few sessions + + + align:start position:0% +few few sessions +okay before too long we'll get into what + + align:start position:0% +okay before too long we'll get into what + + + align:start position:0% +okay before too long we'll get into what +is often called modern physics the the + + align:start position:0% +is often called modern physics the the + + + align:start position:0% +is often called modern physics the the +quite dramatic intellectual changes uh + + align:start position:0% +quite dramatic intellectual changes uh + + + align:start position:0% +quite dramatic intellectual changes uh +taking place roughly speaking in the + + align:start position:0% +taking place roughly speaking in the + + + align:start position:0% +taking place roughly speaking in the +first 25 years of the 20th century + + align:start position:0% +first 25 years of the 20th century + + + align:start position:0% +first 25 years of the 20th century +roughly with with some error bars on + + align:start position:0% +roughly with with some error bars on + + + align:start position:0% +roughly with with some error bars on +that estimate so we'll talk quickly + + align:start position:0% +that estimate so we'll talk quickly + + + align:start position:0% +that estimate so we'll talk quickly +about uh work by Albert Einstein and + + align:start position:0% +about uh work by Albert Einstein and + + + align:start position:0% +about uh work by Albert Einstein and +indeed a circle of colleagues what + + align:start position:0% +indeed a circle of colleagues what + + + align:start position:0% +indeed a circle of colleagues what +became known as uh the special theory of + + align:start position:0% +became known as uh the special theory of + + + align:start position:0% +became known as uh the special theory of +relativity and even some general + + align:start position:0% +relativity and even some general + + + align:start position:0% +relativity and even some general +relativity very near to my heart + + align:start position:0% +relativity very near to my heart + + + align:start position:0% +relativity very near to my heart +Tiffany's heart + + align:start position:0% +Tiffany's heart + + + align:start position:0% +Tiffany's heart +maybe to many of your hearts uh well how + + align:start position:0% +maybe to many of your hearts uh well how + + + align:start position:0% +maybe to many of your hearts uh well how +did Einstein come to these ideas with + + align:start position:0% +did Einstein come to these ideas with + + + align:start position:0% +did Einstein come to these ideas with +whom to what end what was he doing + + align:start position:0% +whom to what end what was he doing + + + align:start position:0% +whom to what end what was he doing +literally what path was he walking each + + align:start position:0% +literally what path was he walking each + + + align:start position:0% +literally what path was he walking each +day as he began contemplating space-time + + align:start position:0% +day as he began contemplating space-time + + + align:start position:0% +day as he began contemplating space-time +and matter uh well then shift to early + + align:start position:0% +and matter uh well then shift to early + + + align:start position:0% +and matter uh well then shift to early +quantum theory as the next main kind of + + align:start position:0% +quantum theory as the next main kind of + + + align:start position:0% +quantum theory as the next main kind of +set within this unit uh and again some + + align:start position:0% +set within this unit uh and again some + + + align:start position:0% +set within this unit uh and again some +some remarkable familiarities some + + align:start position:0% +some remarkable familiarities some + + + align:start position:0% +some remarkable familiarities some +equations we still use 100 to 120 years + + align:start position:0% +equations we still use 100 to 120 years + + + align:start position:0% +equations we still use 100 to 120 years +later + + align:start position:0% +later + + + align:start position:0% +later +I mean but what we think those equations + + align:start position:0% +I mean but what we think those equations + + + align:start position:0% +I mean but what we think those equations +are telling us that actually has not + + align:start position:0% +are telling us that actually has not + + + align:start position:0% +are telling us that actually has not +been so constant where people were + + align:start position:0% +been so constant where people were + + + align:start position:0% +been so constant where people were +working or coming up with the ideas or + + align:start position:0% +working or coming up with the ideas or + + + align:start position:0% +working or coming up with the ideas or +with whom they're interacting is also + + align:start position:0% +with whom they're interacting is also + + + align:start position:0% +with whom they're interacting is also +not so constant so we'll talk about some + + align:start position:0% +not so constant so we'll talk about some + + + align:start position:0% +not so constant so we'll talk about some +shifting institutions like the physic + + align:start position:0% +shifting institutions like the physic + + + align:start position:0% +shifting institutions like the physic +College technician hi Sean stop that + + align:start position:0% +College technician hi Sean stop that + + + align:start position:0% +College technician hi Sean stop that +reminds me to apologize to any people on + + align:start position:0% +reminds me to apologize to any people on + + + align:start position:0% +reminds me to apologize to any people on +the call who actually speak German I + + align:start position:0% +the call who actually speak German I + + + align:start position:0% +the call who actually speak German I +speak incredibly bad German but I love + + align:start position:0% +speak incredibly bad German but I love + + + align:start position:0% +speak incredibly bad German but I love +trying we'll have especially in this + + align:start position:0% +trying we'll have especially in this + + + align:start position:0% +trying we'll have especially in this +first unit a lot of German that I will + + align:start position:0% +first unit a lot of German that I will + + + align:start position:0% +first unit a lot of German that I will +likely mangle + + align:start position:0% +likely mangle + + + align:start position:0% +likely mangle +if you know zero German then you're + + align:start position:0% +if you know zero German then you're + + + align:start position:0% +if you know zero German then you're +actually closer to me than you might + + align:start position:0% +actually closer to me than you might + + + align:start position:0% +actually closer to me than you might +think but nonetheless we'll have some + + align:start position:0% +think but nonetheless we'll have some + + + align:start position:0% +think but nonetheless we'll have some +German stuff don't worry if it's uh if + + align:start position:0% +German stuff don't worry if it's uh if + + + align:start position:0% +German stuff don't worry if it's uh if +it literally sounds foreign or + + align:start position:0% +it literally sounds foreign or + + + align:start position:0% +it literally sounds foreign or +unfamiliar the point is there were some + + align:start position:0% +unfamiliar the point is there were some + + + align:start position:0% +unfamiliar the point is there were some +new institutions new priorities new + + align:start position:0% +new institutions new priorities new + + + align:start position:0% +new institutions new priorities new +national scale uh investment and things + + align:start position:0% +national scale uh investment and things + + + align:start position:0% +national scale uh investment and things +like physics and related fields of + + align:start position:0% +like physics and related fields of + + + align:start position:0% +like physics and related fields of +engineering what role did that play in + + align:start position:0% +engineering what role did that play in + + + align:start position:0% +engineering what role did that play in +the kind of heady years of the early + + align:start position:0% +the kind of heady years of the early + + + align:start position:0% +the kind of heady years of the early +onset of quantum theory and modern + + align:start position:0% +onset of quantum theory and modern + + + align:start position:0% +onset of quantum theory and modern +physics and then where did those ideas + + align:start position:0% +physics and then where did those ideas + + + align:start position:0% +physics and then where did those ideas +lead some of the leading thinkers we'll + + align:start position:0% +lead some of the leading thinkers we'll + + + align:start position:0% +lead some of the leading thinkers we'll +talk of course of course about things + + align:start position:0% +talk of course of course about things + + + align:start position:0% +talk of course of course about things +like Schrodinger's cat or quantum + + align:start position:0% +like Schrodinger's cat or quantum + + + align:start position:0% +like Schrodinger's cat or quantum +entanglement or Einstein podelski Rose + + align:start position:0% +entanglement or Einstein podelski Rose + + + align:start position:0% +entanglement or Einstein podelski Rose +and uh and many many really quite + + align:start position:0% +and uh and many many really quite + + + align:start position:0% +and uh and many many really quite +delicious and delightful elements of + + align:start position:0% +delicious and delightful elements of + + + align:start position:0% +delicious and delightful elements of +quantum theory that I still um wrestle + + align:start position:0% +quantum theory that I still um wrestle + + + align:start position:0% +quantum theory that I still um wrestle +with and get to play with with my own + + align:start position:0% +with and get to play with with my own + + + align:start position:0% +with and get to play with with my own +students and colleagues to this day so + + align:start position:0% +students and colleagues to this day so + + + align:start position:0% +students and colleagues to this day so +that's the the first kind of main unit + + align:start position:0% +that's the the first kind of main unit + + + align:start position:0% +that's the the first kind of main unit +we'll we'll have a kind of quick + + align:start position:0% +we'll we'll have a kind of quick + + + align:start position:0% +we'll we'll have a kind of quick +um uh introduction with his 19th century + + align:start position:0% +um uh introduction with his 19th century + + + align:start position:0% +um uh introduction with his 19th century +Legacy really to set the stage for what + + align:start position:0% +Legacy really to set the stage for what + + + align:start position:0% +Legacy really to set the stage for what +we might call the emergence of modern + + align:start position:0% +we might call the emergence of modern + + + align:start position:0% +we might call the emergence of modern +physics as was recognized even in its + + align:start position:0% +physics as was recognized even in its + + + align:start position:0% +physics as was recognized even in its +day that's the first main unit the + + align:start position:0% +day that's the first main unit the + + + align:start position:0% +day that's the first main unit the +second year of the class + + align:start position:0% +second year of the class + + + align:start position:0% +second year of the class +them we're going to shift again in + + align:start position:0% +them we're going to shift again in + + + align:start position:0% +them we're going to shift again in +remarkably rapid order I mean to an + + align:start position:0% +remarkably rapid order I mean to an + + + align:start position:0% +remarkably rapid order I mean to an +historian the time delay was vanishingly + + align:start position:0% +historian the time delay was vanishingly + + + align:start position:0% +historian the time delay was vanishingly +short a matter of of 10 to 20 years + + align:start position:0% +short a matter of of 10 to 20 years + + + align:start position:0% +short a matter of of 10 to 20 years +being on how one counts + + align:start position:0% +being on how one counts + + + align:start position:0% +being on how one counts +some of those previously very heady very + + align:start position:0% +some of those previously very heady very + + + align:start position:0% +some of those previously very heady very +very esoteric or abstract ideas about + + align:start position:0% +very esoteric or abstract ideas about + + + align:start position:0% +very esoteric or abstract ideas about +atoms about parts of atoms about nuclei + + align:start position:0% +atoms about parts of atoms about nuclei + + + align:start position:0% +atoms about parts of atoms about nuclei +and nuclear forces they began having an + + align:start position:0% +and nuclear forces they began having an + + + align:start position:0% +and nuclear forces they began having an +import and and a priority well beyond uh + + align:start position:0% +import and and a priority well beyond uh + + + align:start position:0% +import and and a priority well beyond uh +professional physicists and chemists or + + align:start position:0% +professional physicists and chemists or + + + align:start position:0% +professional physicists and chemists or +other uh engineers and so on in a way + + align:start position:0% +other uh engineers and so on in a way + + + align:start position:0% +other uh engineers and so on in a way +that again I'm sure are at least in part + + align:start position:0% +that again I'm sure are at least in part + + + align:start position:0% +that again I'm sure are at least in part +familiar to you we're going to sit quite + + align:start position:0% +familiar to you we're going to sit quite + + + align:start position:0% +familiar to you we're going to sit quite +a while with the development of nuclear + + align:start position:0% +a while with the development of nuclear + + + align:start position:0% +a while with the development of nuclear +weapons + + align:start position:0% +weapons + + + align:start position:0% +weapons +Nuclear Physics more broadly but + + align:start position:0% +Nuclear Physics more broadly but + + + align:start position:0% +Nuclear Physics more broadly but +especially the weapons projects during + + align:start position:0% +especially the weapons projects during + + + align:start position:0% +especially the weapons projects during +the second World War uh The Unbelievable + + align:start position:0% +the second World War uh The Unbelievable + + + align:start position:0% +the second World War uh The Unbelievable +transformation of the kind of research + + align:start position:0% +transformation of the kind of research + + + align:start position:0% +transformation of the kind of research +and development infrastructure which + + align:start position:0% +and development infrastructure which + + + align:start position:0% +and development infrastructure which +really starts setting a kind of um + + align:start position:0% +really starts setting a kind of um + + + align:start position:0% +really starts setting a kind of um +blueprint for many features that we + + align:start position:0% +blueprint for many features that we + + + align:start position:0% +blueprint for many features that we +would recognize today even though there + + align:start position:0% +would recognize today even though there + + + align:start position:0% +would recognize today even though there +were forged during a war that itself + + align:start position:0% +were forged during a war that itself + + + align:start position:0% +were forged during a war that itself +ended 75 years ago so we see a change in + + align:start position:0% +ended 75 years ago so we see a change in + + + align:start position:0% +ended 75 years ago so we see a change in +what it means to try to do physics for + + align:start position:0% +what it means to try to do physics for + + + align:start position:0% +what it means to try to do physics for +whom to what ends with what kind of + + align:start position:0% +whom to what ends with what kind of + + + align:start position:0% +whom to what ends with what kind of +support uh and and with what kind of + + align:start position:0% +support uh and and with what kind of + + + align:start position:0% +support uh and and with what kind of +institutional settings uh leading to + + align:start position:0% +institutional settings uh leading to + + + align:start position:0% +institutional settings uh leading to +among other things the use of these very + + align:start position:0% +among other things the use of these very + + + align:start position:0% +among other things the use of these very +new types of weapons again just 75 years + + align:start position:0% +new types of weapons again just 75 years + + + align:start position:0% +new types of weapons again just 75 years +ago against the Japanese cities of + + align:start position:0% +ago against the Japanese cities of + + + align:start position:0% +ago against the Japanese cities of +Hiroshima and Nagasaki in the summer of + + align:start position:0% +Hiroshima and Nagasaki in the summer of + + + align:start position:0% +Hiroshima and Nagasaki in the summer of +1945. so that second main unit third + + align:start position:0% +1945. so that second main unit third + + + align:start position:0% +1945. so that second main unit third +unit of the course the second kind of + + align:start position:0% +unit of the course the second kind of + + + align:start position:0% +unit of the course the second kind of +big juicy thick unit that will sit with + + align:start position:0% +big juicy thick unit that will sit with + + + align:start position:0% +big juicy thick unit that will sit with +for quite a while + + align:start position:0% +for quite a while + + + align:start position:0% +for quite a while +is the kind of new enrollment the new + + align:start position:0% +is the kind of new enrollment the new + + + align:start position:0% +is the kind of new enrollment the new +engagement of physicists chemists + + align:start position:0% +engagement of physicists chemists + + + align:start position:0% +engagement of physicists chemists +various kinds of Engineers with the + + align:start position:0% +various kinds of Engineers with the + + + align:start position:0% +various kinds of Engineers with the +nation-state in times of War and what + + align:start position:0% +nation-state in times of War and what + + + align:start position:0% +nation-state in times of War and what +does that mean for the ideas of physics + + align:start position:0% +does that mean for the ideas of physics + + + align:start position:0% +does that mean for the ideas of physics +for the population of physicists for the + + align:start position:0% +for the population of physicists for the + + + align:start position:0% +for the population of physicists for the +institutions of physics and so on that's + + align:start position:0% +institutions of physics and so on that's + + + align:start position:0% +institutions of physics and so on that's +a big there's a lot to try to really + + align:start position:0% +a big there's a lot to try to really + + + align:start position:0% +a big there's a lot to try to really +understand including a lot of again + + align:start position:0% +understand including a lot of again + + + align:start position:0% +understand including a lot of again +frankly very fascinating uh Cutting Edge + + align:start position:0% +frankly very fascinating uh Cutting Edge + + + align:start position:0% +frankly very fascinating uh Cutting Edge +science and engineering but it was being + + align:start position:0% +science and engineering but it was being + + + align:start position:0% +science and engineering but it was being +done in very specific + + align:start position:0% +done in very specific + + + align:start position:0% +done in very specific +um contexts toward very particular + + align:start position:0% +um contexts toward very particular + + + align:start position:0% +um contexts toward very particular +ethics so we'll spend some some time uh + + align:start position:0% +ethics so we'll spend some some time uh + + + align:start position:0% +ethics so we'll spend some some time uh +around middle of the semester on that + + align:start position:0% +around middle of the semester on that + + + align:start position:0% +around middle of the semester on that +material + + align:start position:0% + + + + align:start position:0% + +the last main unit + + align:start position:0% +the last main unit + + + align:start position:0% +the last main unit +is that expanding outward from the end + + align:start position:0% +is that expanding outward from the end + + + align:start position:0% +is that expanding outward from the end +of World War II + + align:start position:0% +of World War II + + + align:start position:0% +of World War II +here I was a little more selective I + + align:start position:0% +here I was a little more selective I + + + align:start position:0% +here I was a little more selective I +wanted to cover topics that frankly I + + align:start position:0% +wanted to cover topics that frankly I + + + align:start position:0% +wanted to cover topics that frankly I +like most so uh and that means the + + align:start position:0% +like most so uh and that means the + + + align:start position:0% +like most so uh and that means the +topics are very much biased towards um + + align:start position:0% +topics are very much biased towards um + + + align:start position:0% +topics are very much biased towards um +particle physics uh high energy physics + + align:start position:0% +particle physics uh high energy physics + + + align:start position:0% +particle physics uh high energy physics +and astrophysics and cosmology because + + align:start position:0% +and astrophysics and cosmology because + + + align:start position:0% +and astrophysics and cosmology because +first of all this is objectively the + + align:start position:0% +first of all this is objectively the + + + align:start position:0% +first of all this is objectively the +most interesting that was a joke I just + + align:start position:0% +most interesting that was a joke I just + + + align:start position:0% +most interesting that was a joke I just +think they're actually awesome those are + + align:start position:0% +think they're actually awesome those are + + + align:start position:0% +think they're actually awesome those are +the areas that I am most familiar with + + align:start position:0% +the areas that I am most familiar with + + + align:start position:0% +the areas that I am most familiar with +both historically and also in terms of + + align:start position:0% +both historically and also in terms of + + + align:start position:0% +both historically and also in terms of +more contemporary research and so again + + align:start position:0% +more contemporary research and so again + + + align:start position:0% +more contemporary research and so again +it's an opportunity to kind of take a + + align:start position:0% +it's an opportunity to kind of take a + + + align:start position:0% +it's an opportunity to kind of take a +sample to explore some material that + + align:start position:0% +sample to explore some material that + + + align:start position:0% +sample to explore some material that +that might be quite new uh to many of + + align:start position:0% +that might be quite new uh to many of + + + align:start position:0% +that might be quite new uh to many of +you you might not have had a chance to + + align:start position:0% +you you might not have had a chance to + + + align:start position:0% +you you might not have had a chance to +have a full semester course on Quantum + + align:start position:0% +have a full semester course on Quantum + + + align:start position:0% +have a full semester course on Quantum +field Theory or particle theory or uh + + align:start position:0% +field Theory or particle theory or uh + + + align:start position:0% +field Theory or particle theory or uh +contemporary cosmology some of you might + + align:start position:0% +contemporary cosmology some of you might + + + align:start position:0% +contemporary cosmology some of you might +have but there's again no no need to + + align:start position:0% +have but there's again no no need to + + + align:start position:0% +have but there's again no no need to +have already seen this material and + + align:start position:0% +have already seen this material and + + + align:start position:0% +have already seen this material and +we'll we'll be able to kind of sample + + align:start position:0% +we'll we'll be able to kind of sample + + + align:start position:0% +we'll we'll be able to kind of sample +some of these uh Inc still changing + + align:start position:0% +some of these uh Inc still changing + + + align:start position:0% +some of these uh Inc still changing +ideas within again some still changing + + align:start position:0% +ideas within again some still changing + + + align:start position:0% +ideas within again some still changing +institutions who wanted to pursue those + + align:start position:0% +institutions who wanted to pursue those + + + align:start position:0% +institutions who wanted to pursue those +questions why to what ends and in what + + align:start position:0% +questions why to what ends and in what + + + align:start position:0% +questions why to what ends and in what +facilities so now we get to a place uh + + align:start position:0% +facilities so now we get to a place uh + + + align:start position:0% +facilities so now we get to a place uh +in time like uh the Large Hadron + + align:start position:0% +in time like uh the Large Hadron + + + align:start position:0% +in time like uh the Large Hadron +Collider CERN uh the device was + + align:start position:0% +Collider CERN uh the device was + + + align:start position:0% +Collider CERN uh the device was +completed in the uh first decade of the + + align:start position:0% +completed in the uh first decade of the + + + align:start position:0% +completed in the uh first decade of the +21st century you see an aerial shot here + + align:start position:0% +21st century you see an aerial shot here + + + align:start position:0% +21st century you see an aerial shot here +what brought us from an arrow in + + align:start position:0% +what brought us from an arrow in + + + align:start position:0% +what brought us from an arrow in +particle acceler is still where on the + + align:start position:0% +particle acceler is still where on the + + + align:start position:0% +particle acceler is still where on the +size of a kind of person more or less to + + align:start position:0% +size of a kind of person more or less to + + + align:start position:0% +size of a kind of person more or less to +when they when they actually cross + + align:start position:0% +when they when they actually cross + + + align:start position:0% +when they when they actually cross +National borders where the accelerated + + align:start position:0% +National borders where the accelerated + + + align:start position:0% +National borders where the accelerated +protons cross between the Swiss and + + align:start position:0% +protons cross between the Swiss and + + + align:start position:0% +protons cross between the Swiss and +French borders billions of times per + + align:start position:0% +French borders billions of times per + + + align:start position:0% +French borders billions of times per +second so we'll end the course looking + + align:start position:0% +second so we'll end the course looking + + + align:start position:0% +second so we'll end the course looking +outward toward the cosmos uh that way + + align:start position:0% +outward toward the cosmos uh that way + + + align:start position:0% +outward toward the cosmos uh that way +so here's the very last slide I always + + align:start position:0% +so here's the very last slide I always + + + align:start position:0% +so here's the very last slide I always +like to say this course has one actual + + align:start position:0% +like to say this course has one actual + + + align:start position:0% +like to say this course has one actual +goal which is to make sense of this + + align:start position:0% +goal which is to make sense of this + + + align:start position:0% +goal which is to make sense of this +quotation I never Tire of repeating this + + align:start position:0% +quotation I never Tire of repeating this + + + align:start position:0% +quotation I never Tire of repeating this +quotation it was published in Harper's + + align:start position:0% +quotation it was published in Harper's + + + align:start position:0% +quotation it was published in Harper's +magazine just months after the end of + + align:start position:0% +magazine just months after the end of + + + align:start position:0% +magazine just months after the end of +the second world war observing what had + + align:start position:0% +the second world war observing what had + + + align:start position:0% +the second world war observing what had +become a real sea change in the place of + + align:start position:0% +become a real sea change in the place of + + + align:start position:0% +become a real sea change in the place of +physics and especially physicists in + + align:start position:0% +physics and especially physicists in + + + align:start position:0% +physics and especially physicists in +broader Society so this kind of witty uh + + align:start position:0% +broader Society so this kind of witty uh + + + align:start position:0% +broader Society so this kind of witty uh +kind of pundit colonists wrote in in the + + align:start position:0% +kind of pundit colonists wrote in in the + + + align:start position:0% +kind of pundit colonists wrote in in the +spring of 46 the physical scientists are + + align:start position:0% +spring of 46 the physical scientists are + + + align:start position:0% +spring of 46 the physical scientists are +in Vogue these days no dinner party is a + + align:start position:0% +in Vogue these days no dinner party is a + + + align:start position:0% +in Vogue these days no dinner party is a +success but at least when physicists and + + align:start position:0% +success but at least when physicists and + + + align:start position:0% +success but at least when physicists and +really I want to know what happened how + + align:start position:0% +really I want to know what happened how + + + align:start position:0% +really I want to know what happened how +come so many people have dinner now + + align:start position:0% +come so many people have dinner now + + + align:start position:0% +come so many people have dinner now +without inviting us that's really why I + + align:start position:0% +without inviting us that's really why I + + + align:start position:0% +without inviting us that's really why I +put this whole course together together + + align:start position:0% +put this whole course together together + + + align:start position:0% +put this whole course together together +we'll try to answer that question that's + + align:start position:0% +we'll try to answer that question that's + + + align:start position:0% +we'll try to answer that question that's +only modestly tongue-in-cheek any + + align:start position:0% +only modestly tongue-in-cheek any + + + align:start position:0% +only modestly tongue-in-cheek any +questions about any of the of that + + align:start position:0% +questions about any of the of that + + + align:start position:0% +questions about any of the of that +material of course Logistics course + + align:start position:0% +material of course Logistics course + + + align:start position:0% +material of course Logistics course +overview any of that any of that kind of + + align:start position:0% +overview any of that any of that kind of + + + align:start position:0% +overview any of that any of that kind of +stuff + + align:start position:0% +stuff + + + align:start position:0% +stuff +alrighty well thank you everyone uh good + + align:start position:0% +alrighty well thank you everyone uh good + + + align:start position:0% +alrighty well thank you everyone uh good +to see you at least in small little + + align:start position:0% +to see you at least in small little + + + align:start position:0% +to see you at least in small little +squares uh stay well good luck with the + + align:start position:0% +squares uh stay well good luck with the + + + align:start position:0% +squares uh stay well good luck with the +rest of the start of the term and uh and + + align:start position:0% +rest of the start of the term and uh and + + + align:start position:0% +rest of the start of the term and uh and +I look forward to uh to seeing you next + + align:start position:0% +I look forward to uh to seeing you next + + + align:start position:0% +I look forward to uh to seeing you next +week + + align:start position:0% +week + + + align:start position:0% +week +stay well everyone take care \ No newline at end of file diff --git a/PqZj8pySQiU.txt b/PqZj8pySQiU.txt new file mode 100644 index 0000000000000000000000000000000000000000..c6e0b5746a145c183eb5b56fa6ea2b53b30bf2e6 --- /dev/null +++ b/PqZj8pySQiU.txt @@ -0,0 +1,346 @@ +Previously, we learned the +concept of independent + +experiments. + +In this exercise, we'll see how +the seemingly simple idea + +of independence can help us +understand the behavior of + +quite complex systems. + +In particular, we'll combined +the concept of independence + +with the idea of divide and +conquer, where we break a + +larger system into smaller +components, and then using + +independent properties to +glue them back together. + +Now, let's take a look +at the problem. + +We are given a network of +connected components, and each + +component can be good with + +probability P or bad otherwise. + +All components are independent +from each other. + +We say the system is operational +if there exists a + +path connecting point A here +to point B that go through + +only the good components. + +And we'd like to understand, +what is the probability that + +system is operational? + +Which we'll denote +by P of A to B. + +Although the problem might seem +a little complicated at + +the beginning, it turns +out only two + +structures really matter. + +So let's look at each of them. + +In the first structure, which we +call the serial structure, + +we have a collection of k +components, each one having + +probability P being good, +connected one next to each + +other in a serial line. + +Now, in this structure, in order +for there to be a good + +path from A to B, every +single one of the + +components must be working. + +So the probability of having +a good path from A to B is + +simply P times P, so on and so, +repeated k times, which is + +P raised to the k power. + +Know that the reason we can +write the probability this + +way, in terms of this product, +is because of the + +independence property. + + + +Now, the second useful + +structure is parallel structure. + +Here again, we have k components +one, two, through + +k, but this time they're +connected in parallel to each + +other, namely they start from +one point here and ends at + +another point here, +and this holds for + +every single component. + +Now, for the parallel structure +to work, namely for + +there to exist a good path from +A to B, it's easy to see + +that as long as one of these +components works the whole + +thing will work. + +So the probability of A to B +is the probability that at + +least one of these +components works. + +Or in the other word, the +probability of the complement + +of the event where all +components fail. + +Now, if each component has +probability P to be good, then + +the probability that all key +components fail is 1 minus P + +raised to the kth power. + +Again, having this expression +means that we have used the + +property of independence, and +that is probability of having + +a good parallel structure. + +Now, there's one more +observation that will be + +useful for us. + +Just like how we define two +components to be independent, + +we can also find two collections +of components to + +be independent from +each other. + +For example, in this diagram, +if we call the components + +between points C and E as +collection two, and the + +components between E and +B as collection three. + +Now, if we assume that each +component in both + +collections-- + +they're completely independent +from each other, then it's not + +hard to see that collection +two and three behave + +independently. + +And this will be very helpful +in getting us the breakdown + +from complex networks +to simpler elements. + +Now, let's go back to the +original problem of + +calculating the probability of +having a good path from point + +big A to point big B +in this diagram. + +Based on that argument of +independent collections, we + +can first divide the whole +network into three + +collections, as you see here, +from A to C, C to E and E to + +B. Now, because they're +independent and in a serial + +structure, as seen by the +definition of a serial + +structure here, we see that the +probability of A to B can + +be written as a probability of +A to C multiplied by C to E, + +and finally, E to B. + +Now, the probability of A to +C is simply P because the + +collection contains +only one element. + +And similarly, the probability +of E to B is not that hard + +knowing the parallel +structure here. + +We see that collection three +has two components in + +parallel, so this probability +will be given by 1 minus 1 + +minus P squared. + + + +And it remains to calculate just +the probability of having + +a good path from point C to +point E. To get a value for P + +C to E, we notice again, that +this area can be treated as + +two components, C1 to E and C2 +to E connected in parallel. + +And using the parallel law we +get this probability is 1 + +minus 1 minus P C1 to E +multiplied by the 1 minus P C2 + +to E. Know that I'm using two +different characters, C1 and + +C2, to denote the same node, +which is C. This is simply for + +making it easier to analyze +two branches where they + +actually do note +the same node. + +Now P C1 to E is another serial +connection of these + +three elements here with +another component. + +So the first three elements are +connected in parallel, and + +we know the probability of that +being successful is 1 + +minus P3, and the +last one is P. + +And finally, P C2 to E. It's +just a single element + +component with probability of +successful being P. At this + +point, there is no longer any +unknown variables, and we have + +indeed obtained exact values +for all the quantities that + +we're interested in. + +So starting from this equation, +we can plug in the + +values for P C2 to E, P C1 to E +back here, and then further + +plug in P C to E back here. + +That will give us the final +solution, which is given by + +the following somewhat +complicated formula. + +So in summary, in this problem, +we learned how to use + +the independence property among +different components to + +break down the entire fairly +complex network into simple + +modular components, and use the +law of serial and parallel + +connections to put the +probabilities back together in + +common with the overall success +probability of finding + +a path from A to B. \ No newline at end of file diff --git a/QTdJiG7mV40.txt b/QTdJiG7mV40.txt new file mode 100644 index 0000000000000000000000000000000000000000..58a0ada2987186170605a351f74a6d5da3f41646 --- /dev/null +++ b/QTdJiG7mV40.txt @@ -0,0 +1,7659 @@ +align:start position:0% + +so what are we going to do today so + + align:start position:0% +so what are we going to do today so + + + align:start position:0% +so what are we going to do today so +today we're going to continue with amino + + align:start position:0% +today we're going to continue with amino + + + align:start position:0% +today we're going to continue with amino +acids peptides and proteins and I'm + + align:start position:0% +acids peptides and proteins and I'm + + + align:start position:0% +acids peptides and proteins and I'm +going to talk about a different protein + + align:start position:0% +going to talk about a different protein + + + align:start position:0% +going to talk about a different protein +variant that is the causative the cause + + align:start position:0% +variant that is the causative the cause + + + align:start position:0% +variant that is the causative the cause +of sickle cell anemia and it's a very + + align:start position:0% +of sickle cell anemia and it's a very + + + align:start position:0% +of sickle cell anemia and it's a very +interesting structural issue but let me + + align:start position:0% +interesting structural issue but let me + + + align:start position:0% +interesting structural issue but let me +very briefly recap what we did last time + + align:start position:0% +very briefly recap what we did last time + + + align:start position:0% +very briefly recap what we did last time +and then talk to you a little bit about + + align:start position:0% +and then talk to you a little bit about + + + align:start position:0% +and then talk to you a little bit about +a process known as denaturation so last + + align:start position:0% +a process known as denaturation so last + + + align:start position:0% +a process known as denaturation so last +time we discussed how the primary + + align:start position:0% +time we discussed how the primary + + + align:start position:0% +time we discussed how the primary +sequence of a polypeptide chain defines + + align:start position:0% +sequence of a polypeptide chain defines + + + align:start position:0% +sequence of a polypeptide chain defines +its folded structure the folded + + align:start position:0% +its folded structure the folded + + + align:start position:0% +its folded structure the folded +structure is put in place with secondary + + align:start position:0% +structure is put in place with secondary + + + align:start position:0% +structure is put in place with secondary +and tertiary interactions non covalent + + align:start position:0% +and tertiary interactions non covalent + + + align:start position:0% +and tertiary interactions non covalent +interactions secondary just between + + align:start position:0% +interactions secondary just between + + + align:start position:0% +interactions secondary just between +amongst backbone and its tertiary sort + + align:start position:0% +amongst backbone and its tertiary sort + + + align:start position:0% +amongst backbone and its tertiary sort +of everything else even including + + align:start position:0% +of everything else even including + + + align:start position:0% +of everything else even including +backbone omits but either with water or + + align:start position:0% +backbone omits but either with water or + + + align:start position:0% +backbone omits but either with water or +a side chain and so on and then there + + align:start position:0% +a side chain and so on and then there + + + align:start position:0% +a side chain and so on and then there +are some proteins that associate into + + align:start position:0% +are some proteins that associate into + + + align:start position:0% +are some proteins that associate into +quaternary structure so these monomer + + align:start position:0% +quaternary structure so these monomer + + + align:start position:0% +quaternary structure so these monomer +subunits as they would be called and I'm + + align:start position:0% +subunits as they would be called and I'm + + + align:start position:0% +subunits as they would be called and I'm +gonna depict this as like a closed + + align:start position:0% +gonna depict this as like a closed + + + align:start position:0% +gonna depict this as like a closed +circle or an open circle may form dimers + + align:start position:0% +circle or an open circle may form dimers + + + align:start position:0% +circle or an open circle may form dimers +of some kind + + align:start position:0% +of some kind + + + align:start position:0% +of some kind +the dimers may be heterodimers or they + + align:start position:0% +the dimers may be heterodimers or they + + + align:start position:0% +the dimers may be heterodimers or they +may be homo dimers or you could form + + align:start position:0% +may be homo dimers or you could form + + + align:start position:0% +may be homo dimers or you could form +trimers tetra MERS and so on and when we + + align:start position:0% +trimers tetra MERS and so on and when we + + + align:start position:0% +trimers tetra MERS and so on and when we +talk about hemoglobin which is the + + align:start position:0% +talk about hemoglobin which is the + + + align:start position:0% +talk about hemoglobin which is the +protein that gets that it has a problem + + align:start position:0% +protein that gets that it has a problem + + + align:start position:0% +protein that gets that it has a problem +is the cause of sickle cell anemia it + + align:start position:0% +is the cause of sickle cell anemia it + + + align:start position:0% +is the cause of sickle cell anemia it +will what you'll see that at is a hetero + + align:start position:0% +will what you'll see that at is a hetero + + + align:start position:0% +will what you'll see that at is a hetero +tetrameric protein so in this sort of + + align:start position:0% +tetrameric protein so in this sort of + + + align:start position:0% +tetrameric protein so in this sort of +rendition you kind of draw it like this + + align:start position:0% +rendition you kind of draw it like this + + + align:start position:0% +rendition you kind of draw it like this +where there are four subunits tour of + + align:start position:0% +where there are four subunits tour of + + + align:start position:0% +where there are four subunits tour of +one flavor and tour of the other and + + align:start position:0% +one flavor and tour of the other and + + + align:start position:0% +one flavor and tour of the other and +that's the quaternary structure of + + align:start position:0% +that's the quaternary structure of + + + align:start position:0% +that's the quaternary structure of +hemoglobin now proteins fold they are + + align:start position:0% +hemoglobin now proteins fold they are + + + align:start position:0% +hemoglobin now proteins fold they are +weak forces that are holding them + + align:start position:0% +weak forces that are holding them + + + align:start position:0% +weak forces that are holding them +together but there's a lot of weak + + align:start position:0% +together but there's a lot of weak + + + align:start position:0% +together but there's a lot of weak +forces but if you subjects a protein to + + align:start position:0% +forces but if you subjects a protein to + + + align:start position:0% +forces but if you subjects a protein to +various treatments that may break up + + align:start position:0% +various treatments that may break up + + + align:start position:0% +various treatments that may break up +those weak forces the protein will + + align:start position:0% +those weak forces the protein will + + + align:start position:0% +those weak forces the protein will +undergo a process of denaturation so + + align:start position:0% +undergo a process of denaturation so + + + align:start position:0% +undergo a process of denaturation so +anyone think of what kinds of things + + align:start position:0% +anyone think of what kinds of things + + + align:start position:0% +anyone think of what kinds of things +would cause protein denaturation yes + + align:start position:0% +would cause protein denaturation yes + + + align:start position:0% +would cause protein denaturation yes +heat is a bad WA is a serious one + + align:start position:0% +heat is a bad WA is a serious one + + + align:start position:0% +heat is a bad WA is a serious one +obviously and heat yes I'll write them + + align:start position:0% +obviously and heat yes I'll write them + + + align:start position:0% +obviously and heat yes I'll write them +all down + + align:start position:0% +all down + + + align:start position:0% +all down +what's your pH so peach acidity basicity + + align:start position:0% +what's your pH so peach acidity basicity + + + align:start position:0% +what's your pH so peach acidity basicity +and we'll talk about why those things + + align:start position:0% +and we'll talk about why those things + + + align:start position:0% +and we'll talk about why those things +cause changes any other thoughts yes oh + + align:start position:0% + + + + align:start position:0% + +yeah so for example salt organic + + align:start position:0% +yeah so for example salt organic + + + align:start position:0% +yeah so for example salt organic +solvents a process that a lot of people + + align:start position:0% +solvents a process that a lot of people + + + align:start position:0% +solvents a process that a lot of people +don't necessarily think about but as + + align:start position:0% +don't necessarily think about but as + + + align:start position:0% +don't necessarily think about but as +engineers some of you will is shear + + align:start position:0% +engineers some of you will is shear + + + align:start position:0% +engineers some of you will is shear +forces so if you're shooting a protein + + align:start position:0% +forces so if you're shooting a protein + + + align:start position:0% +forces so if you're shooting a protein +through a very narrow tubing and there's + + align:start position:0% +through a very narrow tubing and there's + + + align:start position:0% +through a very narrow tubing and there's +high shear forces those who are also + + align:start position:0% +high shear forces those who are also + + + align:start position:0% +high shear forces those who are also +denature proteins so with eat it's very + + align:start position:0% +denature proteins so with eat it's very + + + align:start position:0% +denature proteins so with eat it's very +clear you're gonna break those weak + + align:start position:0% +clear you're gonna break those weak + + + align:start position:0% +clear you're gonna break those weak +bonds and then they you know they can + + align:start position:0% +bonds and then they you know they can + + + align:start position:0% +bonds and then they you know they can +either reform or if you go to to high + + align:start position:0% +either reform or if you go to to high + + + align:start position:0% +either reform or if you go to to high +heat the unfolded protein starts to form + + align:start position:0% +heat the unfolded protein starts to form + + + align:start position:0% +heat the unfolded protein starts to form +aggregates and anyone who has ever + + align:start position:0% +aggregates and anyone who has ever + + + align:start position:0% +aggregates and anyone who has ever +scrambled an egg knows that that is an + + align:start position:0% +scrambled an egg knows that that is an + + + align:start position:0% +scrambled an egg knows that that is an +irreversible process you don't get to + + align:start position:0% +irreversible process you don't get to + + + align:start position:0% +irreversible process you don't get to +cram the egg back into the shell it's + + align:start position:0% +cram the egg back into the shell it's + + + align:start position:0% +cram the egg back into the shell it's +not the same anymore because what you're + + align:start position:0% +not the same anymore because what you're + + + align:start position:0% +not the same anymore because what you're +doing when you're scrambling eggs is + + align:start position:0% +doing when you're scrambling eggs is + + + align:start position:0% +doing when you're scrambling eggs is +denaturing proteins through heat + + align:start position:0% +denaturing proteins through heat + + + align:start position:0% +denaturing proteins through heat +treatment so that's what heat does it + + align:start position:0% +treatment so that's what heat does it + + + align:start position:0% +treatment so that's what heat does it +breaks the forces the the proteins + + align:start position:0% +breaks the forces the the proteins + + + align:start position:0% +breaks the forces the the proteins +stretch out into their denatured state + + align:start position:0% +stretch out into their denatured state + + + align:start position:0% +stretch out into their denatured state +and instead of refolding to a compact + + align:start position:0% +and instead of refolding to a compact + + + align:start position:0% +and instead of refolding to a compact +structure they just start aggregating + + align:start position:0% +structure they just start aggregating + + + align:start position:0% +structure they just start aggregating +with each other and that's pretty much + + align:start position:0% +with each other and that's pretty much + + + align:start position:0% +with each other and that's pretty much +your reverse 'fl ph is interesting why + + align:start position:0% +your reverse 'fl ph is interesting why + + + align:start position:0% +your reverse 'fl ph is interesting why +would pH break up a low temperature why + + align:start position:0% +would pH break up a low temperature why + + + align:start position:0% +would pH break up a low temperature why +would pH cause changes yeah + + align:start position:0% + + + + align:start position:0% + +okay so pH perfect so pH will change the + + align:start position:0% +okay so pH perfect so pH will change the + + + align:start position:0% +okay so pH perfect so pH will change the +charge state of many of your site chains + + align:start position:0% +charge state of many of your site chains + + + align:start position:0% +charge state of many of your site chains +and once you've changed it you might + + align:start position:0% +and once you've changed it you might + + + align:start position:0% +and once you've changed it you might +have had a lovely electrostatic + + align:start position:0% +have had a lovely electrostatic + + + align:start position:0% +have had a lovely electrostatic +interaction but then you go and + + align:start position:0% +interaction but then you go and + + + align:start position:0% +interaction but then you go and +protonate the carboxylic acid and it + + align:start position:0% +protonate the carboxylic acid and it + + + align:start position:0% +protonate the carboxylic acid and it +can't fall in fact it wants the former + + align:start position:0% +can't fall in fact it wants the former + + + align:start position:0% +can't fall in fact it wants the former +it wants to break a partisan as opposed + + align:start position:0% +it wants to break a partisan as opposed + + + align:start position:0% +it wants to break a partisan as opposed +to come together so that is changing + + align:start position:0% +to come together so that is changing + + + align:start position:0% +to come together so that is changing +charge state which causes denaturation + + align:start position:0% +charge state which causes denaturation + + + align:start position:0% +charge state which causes denaturation +salts and organics for example they make + + align:start position:0% +salts and organics for example they make + + + align:start position:0% +salts and organics for example they make +interactions with parts of the protein + + align:start position:0% +interactions with parts of the protein + + + align:start position:0% +interactions with parts of the protein +for example organics organic molecules + + align:start position:0% +for example organics organic molecules + + + align:start position:0% +for example organics organic molecules +may slip into a hydrophobic core and + + align:start position:0% +may slip into a hydrophobic core and + + + align:start position:0% +may slip into a hydrophobic core and +break them up just push them apart they + + align:start position:0% +break them up just push them apart they + + + align:start position:0% +break them up just push them apart they +want to be there and then too many too + + align:start position:0% +want to be there and then too many too + + + align:start position:0% +want to be there and then too many too +much of a high concentration of an + + align:start position:0% +much of a high concentration of an + + + align:start position:0% +much of a high concentration of an +organic solvent that is miscible with + + align:start position:0% +organic solvent that is miscible with + + + align:start position:0% +organic solvent that is miscible with +water and we would say ethanol Osito + + align:start position:0% +water and we would say ethanol Osito + + + align:start position:0% +water and we would say ethanol Osito +nitrile DMSO but you don't need to worry + + align:start position:0% +nitrile DMSO but you don't need to worry + + + align:start position:0% +nitrile DMSO but you don't need to worry +about too much of which details well + + align:start position:0% +about too much of which details well + + + align:start position:0% +about too much of which details well +actually once you get above 10 percent + + align:start position:0% +actually once you get above 10 percent + + + align:start position:0% +actually once you get above 10 percent +or so we'll just start denaturing + + align:start position:0% +or so we'll just start denaturing + + + align:start position:0% +or so we'll just start denaturing +proteins sometimes reversibly but often + + align:start position:0% +proteins sometimes reversibly but often + + + align:start position:0% +proteins sometimes reversibly but often +irreversibly so this is very important + + align:start position:0% +irreversibly so this is very important + + + align:start position:0% +irreversibly so this is very important +to know the proteins are stable but you + + align:start position:0% +to know the proteins are stable but you + + + align:start position:0% +to know the proteins are stable but you +got to treat them nicely there are some + + align:start position:0% +got to treat them nicely there are some + + + align:start position:0% +got to treat them nicely there are some +human diseases that are a result of Mis + + align:start position:0% +human diseases that are a result of Mis + + + align:start position:0% +human diseases that are a result of Mis +folded or aggregated proteins so for + + align:start position:0% +folded or aggregated proteins so for + + + align:start position:0% +folded or aggregated proteins so for +example all the prion diseases are + + align:start position:0% +example all the prion diseases are + + + align:start position:0% +example all the prion diseases are +proteins gone bad pretty much where they + + align:start position:0% +proteins gone bad pretty much where they + + + align:start position:0% +proteins gone bad pretty much where they +not in a folded structure anymore but + + align:start position:0% +not in a folded structure anymore but + + + align:start position:0% +not in a folded structure anymore but +they are in aggregates that cause + + align:start position:0% +they are in aggregates that cause + + + align:start position:0% +they are in aggregates that cause +problems with cellular processes and + + align:start position:0% +problems with cellular processes and + + + align:start position:0% +problems with cellular processes and +toxicity so Alzheimer's disease mad cow + + align:start position:0% +toxicity so Alzheimer's disease mad cow + + + align:start position:0% +toxicity so Alzheimer's disease mad cow +disease a lot of those neurologic + + align:start position:0% +disease a lot of those neurologic + + + align:start position:0% +disease a lot of those neurologic +disorders caused by poorly folded or + + align:start position:0% +disorders caused by poorly folded or + + + align:start position:0% +disorders caused by poorly folded or +very miss folded proteins for examples + + align:start position:0% +very miss folded proteins for examples + + + align:start position:0% +very miss folded proteins for examples +so these are the things we talked about + + align:start position:0% +so these are the things we talked about + + + align:start position:0% +so these are the things we talked about +last time with respect to the flux from + + align:start position:0% +last time with respect to the flux from + + + align:start position:0% +last time with respect to the flux from +primary to secondary to tertiary to + + align:start position:0% +primary to secondary to tertiary to + + + align:start position:0% +primary to secondary to tertiary to +quaternary and that's a perfect time for + + align:start position:0% +quaternary and that's a perfect time for + + + align:start position:0% +quaternary and that's a perfect time for +me to introduce to you what we'll talk + + align:start position:0% +me to introduce to you what we'll talk + + + align:start position:0% +me to introduce to you what we'll talk +about today so last time we talked about + + align:start position:0% +about today so last time we talked about + + + align:start position:0% +about today so last time we talked about +structural proteins and I showed you how + + align:start position:0% +structural proteins and I showed you how + + + align:start position:0% +structural proteins and I showed you how +collagen just with a simple defect + + align:start position:0% +collagen just with a simple defect + + + align:start position:0% +collagen just with a simple defect +changing a glycine to an alanine in one + + align:start position:0% +changing a glycine to an alanine in one + + + align:start position:0% +changing a glycine to an alanine in one +of its subunits really alters the + + align:start position:0% +of its subunits really alters the + + + align:start position:0% +of its subunits really alters the +tertiary the quaternary structure + + align:start position:0% +tertiary the quaternary structure + + + align:start position:0% +tertiary the quaternary structure +the protein to make very weak collagen + + align:start position:0% +the protein to make very weak collagen + + + align:start position:0% +the protein to make very weak collagen +that's no longer supportive of bone + + align:start position:0% +that's no longer supportive of bone + + + align:start position:0% +that's no longer supportive of bone +strength but what I'm going to talk to + + align:start position:0% +strength but what I'm going to talk to + + + align:start position:0% +strength but what I'm going to talk to +you about today is a defect in a + + align:start position:0% +you about today is a defect in a + + + align:start position:0% +you about today is a defect in a +transport protein that carries oxygen + + align:start position:0% +transport protein that carries oxygen + + + align:start position:0% +transport protein that carries oxygen +around the body so we're gonna talk + + align:start position:0% +around the body so we're gonna talk + + + align:start position:0% +around the body so we're gonna talk +about hemoglobin these diseases are what + + align:start position:0% +about hemoglobin these diseases are what + + + align:start position:0% +about hemoglobin these diseases are what +are known as inborn errors of metabolism + + align:start position:0% +are known as inborn errors of metabolism + + + align:start position:0% +are known as inborn errors of metabolism +or that's kind of a complex term or + + align:start position:0% +or that's kind of a complex term or + + + align:start position:0% +or that's kind of a complex term or +genetically linked diseases because + + align:start position:0% +genetically linked diseases because + + + align:start position:0% +genetically linked diseases because +there is a single defect in a DNA strand + + align:start position:0% +there is a single defect in a DNA strand + + + align:start position:0% +there is a single defect in a DNA strand +that then gets transcribed into an RNA + + align:start position:0% +that then gets transcribed into an RNA + + + align:start position:0% +that then gets transcribed into an RNA +strand so one base defect that then + + align:start position:0% +strand so one base defect that then + + + align:start position:0% +strand so one base defect that then +becomes an amino acid defect in your + + align:start position:0% +becomes an amino acid defect in your + + + align:start position:0% +becomes an amino acid defect in your +protein strand so these are tiny changes + + align:start position:0% +protein strand so these are tiny changes + + + align:start position:0% +protein strand so these are tiny changes +in the protein of the cause dramatic + + align:start position:0% +in the protein of the cause dramatic + + + align:start position:0% +in the protein of the cause dramatic +changes in the structure and function of + + align:start position:0% +changes in the structure and function of + + + align:start position:0% +changes in the structure and function of +the protein and what you will see with + + align:start position:0% +the protein and what you will see with + + + align:start position:0% +the protein and what you will see with +hemoglobin is it causes a real problem + + align:start position:0% +hemoglobin is it causes a real problem + + + align:start position:0% +hemoglobin is it causes a real problem +with the quaternary structure and then + + align:start position:0% +with the quaternary structure and then + + + align:start position:0% +with the quaternary structure and then +causes proteins to aggregate so + + align:start position:0% +causes proteins to aggregate so + + + align:start position:0% +causes proteins to aggregate so +hemoglobin is the dominant protein in + + align:start position:0% +hemoglobin is the dominant protein in + + + align:start position:0% +hemoglobin is the dominant protein in +red blood cells or erythrocytes + + align:start position:0% +red blood cells or erythrocytes + + + align:start position:0% +red blood cells or erythrocytes +and in fact the differentiation of the + + align:start position:0% +and in fact the differentiation of the + + + align:start position:0% +and in fact the differentiation of the +red blood cell as it comes from + + align:start position:0% +red blood cell as it comes from + + + align:start position:0% +red blood cell as it comes from +progenitor cells goes through a process + + align:start position:0% +progenitor cells goes through a process + + + align:start position:0% +progenitor cells goes through a process +where the red blood cell dumps out its + + align:start position:0% +where the red blood cell dumps out its + + + align:start position:0% +where the red blood cell dumps out its +nucleus so it can't divide anymore and + + align:start position:0% +nucleus so it can't divide anymore and + + + align:start position:0% +nucleus so it can't divide anymore and +basically the content of the cell is + + align:start position:0% +basically the content of the cell is + + + align:start position:0% +basically the content of the cell is +extremely high in hemoglobin you've + + align:start position:0% +extremely high in hemoglobin you've + + + align:start position:0% +extremely high in hemoglobin you've +packed the hemoglobin into the red blood + + align:start position:0% +packed the hemoglobin into the red blood + + + align:start position:0% +packed the hemoglobin into the red blood +cell at the cost of losing the nucleus + + align:start position:0% +cell at the cost of losing the nucleus + + + align:start position:0% +cell at the cost of losing the nucleus +so that's terminally differentiated + + align:start position:0% +so that's terminally differentiated + + + align:start position:0% +so that's terminally differentiated +can't become a red blood cell and can't + + align:start position:0% +can't become a red blood cell and can't + + + align:start position:0% +can't become a red blood cell and can't +divide anymore and it has about a half + + align:start position:0% +divide anymore and it has about a half + + + align:start position:0% +divide anymore and it has about a half +life they have about a half life 100 + + align:start position:0% +life they have about a half life 100 + + + align:start position:0% +life they have about a half life 100 +days so they turn over and then that's + + align:start position:0% +days so they turn over and then that's + + + align:start position:0% +days so they turn over and then that's +it and when red blood cells turn over + + align:start position:0% +it and when red blood cells turn over + + + align:start position:0% +it and when red blood cells turn over +the hemoglobin has to be taken care of + + align:start position:0% +the hemoglobin has to be taken care of + + + align:start position:0% +the hemoglobin has to be taken care of +in order that is not toxic red blood + + align:start position:0% +in order that is not toxic red blood + + + align:start position:0% +in order that is not toxic red blood +cells are red because of a particular + + align:start position:0% +cells are red because of a particular + + + align:start position:0% +cells are red because of a particular +molecule that's in the hemoglobin + + align:start position:0% +molecule that's in the hemoglobin + + + align:start position:0% +molecule that's in the hemoglobin +called ahima molecule which is bound to + + align:start position:0% +called ahima molecule which is bound to + + + align:start position:0% +called ahima molecule which is bound to +iron which provides the hemoglobin with + + align:start position:0% +iron which provides the hemoglobin with + + + align:start position:0% +iron which provides the hemoglobin with +the capacity to pick up oxygen in your + + align:start position:0% +the capacity to pick up oxygen in your + + + align:start position:0% +the capacity to pick up oxygen in your +lungs travel it around the body and then + + align:start position:0% +lungs travel it around the body and then + + + align:start position:0% +lungs travel it around the body and then +leave it where it's needed and then + + align:start position:0% +leave it where it's needed and then + + + align:start position:0% +leave it where it's needed and then +replace the oxygen with co2 and take the + + align:start position:0% +replace the oxygen with co2 and take the + + + align:start position:0% +replace the oxygen with co2 and take the +co2 back to the lungs in order for you + + align:start position:0% +co2 back to the lungs in order for you + + + align:start position:0% +co2 back to the lungs in order for you +to respire it out okay so he made the + + align:start position:0% +to respire it out okay so he made the + + + align:start position:0% +to respire it out okay so he made the +team aglow beam carries oxygen and co2 + + align:start position:0% +team aglow beam carries oxygen and co2 + + + align:start position:0% +team aglow beam carries oxygen and co2 +from oxygen from the lungs co2 back to + + align:start position:0% +from oxygen from the lungs co2 back to + + + align:start position:0% +from oxygen from the lungs co2 back to +the lungs and the reason why you need + + align:start position:0% +the lungs and the reason why you need + + + align:start position:0% +the lungs and the reason why you need +the iron is that the iron is coordinated + + align:start position:0% +the iron is that the iron is coordinated + + + align:start position:0% +the iron is that the iron is coordinated +to the oxygen so the heme molecule I + + align:start position:0% +to the oxygen so the heme molecule I + + + align:start position:0% +to the oxygen so the heme molecule I +won't draw it if you want to see it it's + + align:start position:0% +won't draw it if you want to see it it's + + + align:start position:0% +won't draw it if you want to see it it's +a big complex organic structure a very + + align:start position:0% +a big complex organic structure a very + + + align:start position:0% +a big complex organic structure a very +interesting structure but something for + + align:start position:0% +interesting structure but something for + + + align:start position:0% +interesting structure but something for +another day here look but I want to + + align:start position:0% +another day here look but I want to + + + align:start position:0% +another day here look but I want to +stress to you that the iron heme complex + + align:start position:0% +stress to you that the iron heme complex + + + align:start position:0% +stress to you that the iron heme complex +is red that's why your blood cells are + + align:start position:0% +is red that's why your blood cells are + + + align:start position:0% +is red that's why your blood cells are +red your blood cells don't have a + + align:start position:0% +red your blood cells don't have a + + + align:start position:0% +red your blood cells don't have a +nucleus so they can cram in lots more + + align:start position:0% +nucleus so they can cram in lots more + + + align:start position:0% +nucleus so they can cram in lots more +hemoglobin so it's kind of a fascinating + + align:start position:0% +hemoglobin so it's kind of a fascinating + + + align:start position:0% +hemoglobin so it's kind of a fascinating +situations so hemoglobin is an example + + align:start position:0% +situations so hemoglobin is an example + + + align:start position:0% +situations so hemoglobin is an example +of a homo tetrameric protein and it has + + align:start position:0% +of a homo tetrameric protein and it has + + + align:start position:0% +of a homo tetrameric protein and it has +four subunits two of one flavor and two + + align:start position:0% +four subunits two of one flavor and two + + + align:start position:0% +four subunits two of one flavor and two +of another so we call this an alpha 2 + + align:start position:0% +of another so we call this an alpha 2 + + + align:start position:0% +of another so we call this an alpha 2 +beta 2 protein differentiating the alpha + + align:start position:0% +beta 2 protein differentiating the alpha + + + align:start position:0% +beta 2 protein differentiating the alpha +subunits and the beat ones yes why isn't + + align:start position:0% +subunits and the beat ones yes why isn't + + + align:start position:0% +subunits and the beat ones yes why isn't +it homo tetrameric this you could ask + + align:start position:0% +it homo tetrameric this you could ask + + + align:start position:0% +it homo tetrameric this you could ask +why is it I don't know I mean there will + + align:start position:0% +why is it I don't know I mean there will + + + align:start position:0% +why is it I don't know I mean there will +be interactions amongst the subunits + + align:start position:0% +be interactions amongst the subunits + + + align:start position:0% +be interactions amongst the subunits +that favor that particular packaging the + + align:start position:0% +that favor that particular packaging the + + + align:start position:0% +that favor that particular packaging the +subunits are kind of similar in shape + + align:start position:0% +subunits are kind of similar in shape + + + align:start position:0% +subunits are kind of similar in shape +they have what's called a globe in fold + + align:start position:0% +they have what's called a globe in fold + + + align:start position:0% +they have what's called a globe in fold +you could more or less pick out those + + align:start position:0% +you could more or less pick out those + + + align:start position:0% +you could more or less pick out those +tubes remember our alpha helixes they + + align:start position:0% +tubes remember our alpha helixes they + + + align:start position:0% +tubes remember our alpha helixes they +could form tetramers that are all the + + align:start position:0% +could form tetramers that are all the + + + align:start position:0% +could form tetramers that are all the +same but the energetically favored form + + align:start position:0% +same but the energetically favored form + + + align:start position:0% +same but the energetically favored form +is the two and two hemoglobin is a + + align:start position:0% +is the two and two hemoglobin is a + + + align:start position:0% +is the two and two hemoglobin is a +tetrameric protein because that's really + + align:start position:0% +tetrameric protein because that's really + + + align:start position:0% +tetrameric protein because that's really +advantageous for picking up + + align:start position:0% +advantageous for picking up + + + align:start position:0% +advantageous for picking up +Sigyn and dropping off oxygen in a very + + align:start position:0% +Sigyn and dropping off oxygen in a very + + + align:start position:0% +Sigyn and dropping off oxygen in a very +narrow oxygen range so there are + + align:start position:0% +narrow oxygen range so there are + + + align:start position:0% +narrow oxygen range so there are +proteins called globins that just one of + + align:start position:0% +proteins called globins that just one of + + + align:start position:0% +proteins called globins that just one of +these that can bind oxygen hemoglobin is + + align:start position:0% +these that can bind oxygen hemoglobin is + + + align:start position:0% +these that can bind oxygen hemoglobin is +tetrameric because it has a cooperative + + align:start position:0% +tetrameric because it has a cooperative + + + align:start position:0% +tetrameric because it has a cooperative +oxygen binding so in a very narrow range + + align:start position:0% +oxygen binding so in a very narrow range + + + align:start position:0% +oxygen binding so in a very narrow range +of oxygen it fills all four sites in the + + align:start position:0% +of oxygen it fills all four sites in the + + + align:start position:0% +of oxygen it fills all four sites in the +tetrameric protein with an oxygen + + align:start position:0% +tetrameric protein with an oxygen + + + align:start position:0% +tetrameric protein with an oxygen +molecule so it's very advantageous in + + align:start position:0% +molecule so it's very advantageous in + + + align:start position:0% +molecule so it's very advantageous in +from a physics perspective that it + + align:start position:0% +from a physics perspective that it + + + align:start position:0% +from a physics perspective that it +responds to very narrow changes in + + align:start position:0% +responds to very narrow changes in + + + align:start position:0% +responds to very narrow changes in +oxygen does that make sense to everyone + + align:start position:0% +oxygen does that make sense to everyone + + + align:start position:0% +oxygen does that make sense to everyone +yeah okay it means cut anything that's + + align:start position:0% +yeah okay it means cut anything that's + + + align:start position:0% +yeah okay it means cut anything that's +cooperative means that one let's say + + align:start position:0% +cooperative means that one let's say + + + align:start position:0% +cooperative means that one let's say +I've got a tetramer of hemoglobin one + + align:start position:0% +I've got a tetramer of hemoglobin one + + + align:start position:0% +I've got a tetramer of hemoglobin one +oxygen binds to one of them so I'm a + + align:start position:0% +oxygen binds to one of them so I'm a + + + align:start position:0% +oxygen binds to one of them so I'm a +binding oxygen here and then binding to + + align:start position:0% +binding oxygen here and then binding to + + + align:start position:0% +binding oxygen here and then binding to +the next the next and the next gets + + align:start position:0% +the next the next and the next gets + + + align:start position:0% +the next the next and the next gets +easier and easier so it's they sort of + + align:start position:0% +easier and easier so it's they sort of + + + align:start position:0% +easier and easier so it's they sort of +want to come in as a team and that's + + align:start position:0% +want to come in as a team and that's + + + align:start position:0% +want to come in as a team and that's +handy for maximizing oxygen transport + + align:start position:0% +handy for maximizing oxygen transport + + + align:start position:0% +handy for maximizing oxygen transport +around the body in a narrow oxygen range + + align:start position:0% +around the body in a narrow oxygen range + + + align:start position:0% +around the body in a narrow oxygen range +which we can only deal with what's out + + align:start position:0% +which we can only deal with what's out + + + align:start position:0% +which we can only deal with what's out +there in the atmosphere so we have to + + align:start position:0% +there in the atmosphere so we have to + + + align:start position:0% +there in the atmosphere so we have to +make this work does that answer your + + align:start position:0% +make this work does that answer your + + + align:start position:0% +make this work does that answer your +question okay all right so where was I + + align:start position:0% +question okay all right so where was I + + + align:start position:0% +question okay all right so where was I +okay so so what we're gonna do today + + align:start position:0% +okay so so what we're gonna do today + + + align:start position:0% +okay so so what we're gonna do today +we're gonna look at hemoglobin + + align:start position:0% +we're gonna look at hemoglobin + + + align:start position:0% +we're gonna look at hemoglobin +it's the tetra mer those discoid + + align:start position:0% +it's the tetra mer those discoid + + + align:start position:0% +it's the tetra mer those discoid +structures are the heme that I just + + align:start position:0% +structures are the heme that I just + + + align:start position:0% +structures are the heme that I just +mentioned I've drawn them as this sort + + align:start position:0% +mentioned I've drawn them as this sort + + + align:start position:0% +mentioned I've drawn them as this sort +of four leaf clover here just for + + align:start position:0% +of four leaf clover here just for + + + align:start position:0% +of four leaf clover here just for +simplicity and there is a single defect + + align:start position:0% +simplicity and there is a single defect + + + align:start position:0% +simplicity and there is a single defect +in the sequence of the single monomer + + align:start position:0% +in the sequence of the single monomer + + + align:start position:0% +in the sequence of the single monomer +subunits in hemoglobin so each of these + + align:start position:0% + + + + align:start position:0% + +so there are four proteins betta globin + + align:start position:0% +so there are four proteins betta globin + + + align:start position:0% +so there are four proteins betta globin +two copies of beta globin and two copies + + align:start position:0% +two copies of beta globin and two copies + + + align:start position:0% +two copies of beta globin and two copies +of alpha globin they are all let me see + + align:start position:0% +of alpha globin they are all let me see + + + align:start position:0% +of alpha globin they are all let me see +what's the size did you deluded it to + + align:start position:0% +what's the size did you deluded it to + + + align:start position:0% +what's the size did you deluded it to +pretty subjective you know I could never + + align:start position:0% +pretty subjective you know I could never + + + align:start position:0% +pretty subjective you know I could never +see things when I'm up at the screen but + + align:start position:0% +see things when I'm up at the screen but + + + align:start position:0% +see things when I'm up at the screen but +they're about 160 156 okay so they're + + align:start position:0% +they're about 160 156 okay so they're + + + align:start position:0% +they're about 160 156 okay so they're +about 146 amino acids long in each of + + align:start position:0% +about 146 amino acids long in each of + + + align:start position:0% +about 146 amino acids long in each of +them and a single defect in a beta + + align:start position:0% +them and a single defect in a beta + + + align:start position:0% +them and a single defect in a beta +globin where you have a change from + + align:start position:0% +globin where you have a change from + + + align:start position:0% +globin where you have a change from +glutamic acid residue 6 to valine + + align:start position:0% +glutamic acid residue 6 to valine + + + align:start position:0% +glutamic acid residue 6 to valine +residue 6 one change in beta globin + + align:start position:0% +residue 6 one change in beta globin + + + align:start position:0% +residue 6 one change in beta globin +which means two changes in the whole + + align:start position:0% +which means two changes in the whole + + + align:start position:0% +which means two changes in the whole +structure because there are two beta + + align:start position:0% +structure because there are two beta + + + align:start position:0% +structure because there are two beta +globin alters the properties of the + + align:start position:0% +globin alters the properties of the + + + align:start position:0% +globin alters the properties of the +hemoglobin and causes what's called + + align:start position:0% +hemoglobin and causes what's called + + + align:start position:0% +hemoglobin and causes what's called +sickling of your red blood cells so + + align:start position:0% +sickling of your red blood cells so + + + align:start position:0% +sickling of your red blood cells so +let's take a look at what that would + + align:start position:0% +let's take a look at what that would + + + align:start position:0% +let's take a look at what that would +look like at the amino acid level + + align:start position:0% +look like at the amino acid level + + + align:start position:0% +look like at the amino acid level +glutamic acid is one of your charged + + align:start position:0% +glutamic acid is one of your charged + + + align:start position:0% +glutamic acid is one of your charged +amino acids I'm just going to draw a + + align:start position:0% +amino acids I'm just going to draw a + + + align:start position:0% +amino acids I'm just going to draw a +little bit of it as it were in a peptide + + align:start position:0% + + + + align:start position:0% + +and it's at position six in the sequence + + align:start position:0% +and it's at position six in the sequence + + + align:start position:0% +and it's at position six in the sequence +so it's six residues from the amino + + align:start position:0% +so it's six residues from the amino + + + align:start position:0% +so it's six residues from the amino +terminus because we always write things + + align:start position:0% +terminus because we always write things + + + align:start position:0% +terminus because we always write things +in this direction and the change takes + + align:start position:0% +in this direction and the change takes + + + align:start position:0% +in this direction and the change takes +place to put in place a valine and + + align:start position:0% + + + + align:start position:0% + +there's a pretty big change in identity + + align:start position:0% +there's a pretty big change in identity + + + align:start position:0% +there's a pretty big change in identity +and personality of those residues you've + + align:start position:0% +and personality of those residues you've + + + align:start position:0% +and personality of those residues you've +gone from polar charged to neutral big + + align:start position:0% +gone from polar charged to neutral big + + + align:start position:0% +gone from polar charged to neutral big +fluffy hydrophobic residue and it's + + align:start position:0% +fluffy hydrophobic residue and it's + + + align:start position:0% +fluffy hydrophobic residue and it's +really amazing so the beta globin is + + align:start position:0% +really amazing so the beta globin is + + + align:start position:0% +really amazing so the beta globin is +expressed on chromosome 11 it's a + + align:start position:0% +expressed on chromosome 11 it's a + + + align:start position:0% +expressed on chromosome 11 it's a +hundred and thirty-four million base + + align:start position:0% +hundred and thirty-four million base + + + align:start position:0% +hundred and thirty-four million base +pairs one base is changed so what you + + align:start position:0% +pairs one base is changed so what you + + + align:start position:0% +pairs one base is changed so what you +have in the DNA in the normal DNA that + + align:start position:0% +have in the DNA in the normal DNA that + + + align:start position:0% +have in the DNA in the normal DNA that +encodes the No + + align:start position:0% +encodes the No + + + align:start position:0% +encodes the No +more beta-globin gene there's a + + align:start position:0% +more beta-globin gene there's a + + + align:start position:0% +more beta-globin gene there's a +particular sequence of nucleic acids + + align:start position:0% +particular sequence of nucleic acids + + + align:start position:0% +particular sequence of nucleic acids +this is what the double strand would + + align:start position:0% +this is what the double strand would + + + align:start position:0% +this is what the double strand would +look like we're gonna see way more about + + align:start position:0% +look like we're gonna see way more about + + + align:start position:0% +look like we're gonna see way more about +nucleic acids next week when that gets + + align:start position:0% +nucleic acids next week when that gets + + + align:start position:0% +nucleic acids next week when that gets +converted to the messenger RNA you get a + + align:start position:0% +converted to the messenger RNA you get a + + + align:start position:0% +converted to the messenger RNA you get a +particular code that in the genetic code + + align:start position:0% +particular code that in the genetic code + + + align:start position:0% +particular code that in the genetic code +codes for glutamic acids everything's + + align:start position:0% +codes for glutamic acids everything's + + + align:start position:0% +codes for glutamic acids everything's +normal a single change if we change the + + align:start position:0% +normal a single change if we change the + + + align:start position:0% +normal a single change if we change the +center nucleic acid within the DNA it + + align:start position:0% +center nucleic acid within the DNA it + + + align:start position:0% +center nucleic acid within the DNA it +makes a different messenger RNA and one + + align:start position:0% +makes a different messenger RNA and one + + + align:start position:0% +makes a different messenger RNA and one +base pair puts in valine instead of + + align:start position:0% +base pair puts in valine instead of + + + align:start position:0% +base pair puts in valine instead of +glutamic acid out of a hundred and + + align:start position:0% +glutamic acid out of a hundred and + + + align:start position:0% +glutamic acid out of a hundred and +thirty-four million base pairs so what + + align:start position:0% +thirty-four million base pairs so what + + + align:start position:0% +thirty-four million base pairs so what +happens in the normal normal hemoglobin + + align:start position:0% +happens in the normal normal hemoglobin + + + align:start position:0% +happens in the normal normal hemoglobin +you have normal behavior you have this + + align:start position:0% +you have normal behavior you have this + + + align:start position:0% +you have normal behavior you have this +tetrameric structure false commits + + align:start position:0% +tetrameric structure false commits + + + align:start position:0% +tetrameric structure false commits +cooperativity carries oxygen it moves + + align:start position:0% +cooperativity carries oxygen it moves + + + align:start position:0% +cooperativity carries oxygen it moves +around the blood low problem excuse me + + align:start position:0% +around the blood low problem excuse me + + + align:start position:0% +around the blood low problem excuse me +it sits in the erythrocytes or red blood + + align:start position:0% +it sits in the erythrocytes or red blood + + + align:start position:0% +it sits in the erythrocytes or red blood +cells no problem the minute you have + + align:start position:0% +cells no problem the minute you have + + + align:start position:0% +cells no problem the minute you have +that mutation the hemoglobin molecules + + align:start position:0% +that mutation the hemoglobin molecules + + + align:start position:0% +that mutation the hemoglobin molecules +start to associate into clusters like + + align:start position:0% +start to associate into clusters like + + + align:start position:0% +start to associate into clusters like +fiber lacrosse thus because each tetra + + align:start position:0% +fiber lacrosse thus because each tetra + + + align:start position:0% +fiber lacrosse thus because each tetra +mer gets glued to another tetra mer and + + align:start position:0% +mer gets glued to another tetra mer and + + + align:start position:0% +mer gets glued to another tetra mer and +another one and another one so you have + + align:start position:0% +another one and another one so you have + + + align:start position:0% +another one and another one so you have +hemoglobin not behaving as this + + align:start position:0% +hemoglobin not behaving as this + + + align:start position:0% +hemoglobin not behaving as this +beautiful independent quaternary + + align:start position:0% +beautiful independent quaternary + + + align:start position:0% +beautiful independent quaternary +structure but rather sticking to + + align:start position:0% +structure but rather sticking to + + + align:start position:0% +structure but rather sticking to +physically sticking to other molecules + + align:start position:0% +physically sticking to other molecules + + + align:start position:0% +physically sticking to other molecules +and those tangles get those molecules + + align:start position:0% +and those tangles get those molecules + + + align:start position:0% +and those tangles get those molecules +get so so large that they start to form + + align:start position:0% +get so so large that they start to form + + + align:start position:0% +get so so large that they start to form +long and inflexible chains and it's such + + align:start position:0% +long and inflexible chains and it's such + + + align:start position:0% +long and inflexible chains and it's such +a dramatic change that that discoid + + align:start position:0% +a dramatic change that that discoid + + + align:start position:0% +a dramatic change that that discoid +structure you're that you're familiar + + align:start position:0% +structure you're that you're familiar + + + align:start position:0% +structure you're that you're familiar +with for red blood cells suddenly + + align:start position:0% +with for red blood cells suddenly + + + align:start position:0% +with for red blood cells suddenly +becomes a sickle shape so that would be + + align:start position:0% +becomes a sickle shape so that would be + + + align:start position:0% +becomes a sickle shape so that would be +the normal cell with normal hemoglobin + + align:start position:0% +the normal cell with normal hemoglobin + + + align:start position:0% +the normal cell with normal hemoglobin +but sickle cell they look like this + + align:start position:0% +but sickle cell they look like this + + + align:start position:0% +but sickle cell they look like this +they're kind of curved odd a very odd + + align:start position:0% +they're kind of curved odd a very odd + + + align:start position:0% +they're kind of curved odd a very odd +shape and the problem is red blood cells + + align:start position:0% +shape and the problem is red blood cells + + + align:start position:0% +shape and the problem is red blood cells +that have evolved to move really + + align:start position:0% +that have evolved to move really + + + align:start position:0% +that have evolved to move really +smoothly through your capillaries as + + align:start position:0% +smoothly through your capillaries as + + + align:start position:0% +smoothly through your capillaries as +soon as you get a different shape that's + + align:start position:0% +soon as you get a different shape that's + + + align:start position:0% +soon as you get a different shape that's +sort of you know not that discoid + + align:start position:0% +sort of you know not that discoid + + + align:start position:0% +sort of you know not that discoid +structure they start clogging in the + + align:start position:0% +structure they start clogging in the + + + align:start position:0% +structure they start clogging in the +capillaries and when you have the defect + + align:start position:0% +capillaries and when you have the defect + + + align:start position:0% +capillaries and when you have the defect +where all of your hemoglobin is messed + + align:start position:0% +where all of your hemoglobin is messed + + + align:start position:0% +where all of your hemoglobin is messed +up with this variation it's incredibly + + align:start position:0% +up with this variation it's incredibly + + + align:start position:0% +up with this variation it's incredibly +painful because think of all your + + align:start position:0% +painful because think of all your + + + align:start position:0% +painful because think of all your +capillary + + align:start position:0% +capillary + + + align:start position:0% +capillary +is going out to the Father reaches of + + align:start position:0% +is going out to the Father reaches of + + + align:start position:0% +is going out to the Father reaches of +your joints there is thin blood vessels + + align:start position:0% +your joints there is thin blood vessels + + + align:start position:0% +your joints there is thin blood vessels +blocked up with the sick old red blood + + align:start position:0% +blocked up with the sick old red blood + + + align:start position:0% +blocked up with the sick old red blood +cells that are caused by the variation + + align:start position:0% +cells that are caused by the variation + + + align:start position:0% +cells that are caused by the variation +in hemoglobin so that one little defect + + align:start position:0% +in hemoglobin so that one little defect + + + align:start position:0% +in hemoglobin so that one little defect +takes us all the way to a serious + + align:start position:0% +takes us all the way to a serious + + + align:start position:0% +takes us all the way to a serious +disease all right so what I want to do + + align:start position:0% +disease all right so what I want to do + + + align:start position:0% +disease all right so what I want to do +very briefly is show you the molecular + + align:start position:0% +very briefly is show you the molecular + + + align:start position:0% +very briefly is show you the molecular +basis for this all right and the defect + + align:start position:0% +basis for this all right and the defect + + + align:start position:0% +basis for this all right and the defect +actually appears on the two beta globin + + align:start position:0% +actually appears on the two beta globin + + + align:start position:0% +actually appears on the two beta globin +chains but right on the outside of the + + align:start position:0% +chains but right on the outside of the + + + align:start position:0% +chains but right on the outside of the +protein not in the middle of the protein + + align:start position:0% +protein not in the middle of the protein + + + align:start position:0% +protein not in the middle of the protein +because this is a defect that affects + + align:start position:0% +because this is a defect that affects + + + align:start position:0% +because this is a defect that affects +how proteins interact with other + + align:start position:0% +how proteins interact with other + + + align:start position:0% +how proteins interact with other +proteins not the function of the protein + + align:start position:0% +proteins not the function of the protein + + + align:start position:0% +proteins not the function of the protein +on its own probably still carries oxygen + + align:start position:0% +on its own probably still carries oxygen + + + align:start position:0% +on its own probably still carries oxygen +just fine but it's the mechanical change + + align:start position:0% +just fine but it's the mechanical change + + + align:start position:0% +just fine but it's the mechanical change +in the hemoglobin that causes the + + align:start position:0% +in the hemoglobin that causes the + + + align:start position:0% +in the hemoglobin that causes the +disease + + align:start position:0% +disease + + + align:start position:0% +disease +okay so sickle cell anemia the + + align:start position:0% +okay so sickle cell anemia the + + + align:start position:0% +okay so sickle cell anemia the +hemoglobin is now called hemoglobin s + + align:start position:0% +hemoglobin is now called hemoglobin s + + + align:start position:0% +hemoglobin is now called hemoglobin s +with that mutation that I just described + + align:start position:0% +with that mutation that I just described + + + align:start position:0% +with that mutation that I just described +and when people have a heterozygous it + + align:start position:0% +and when people have a heterozygous it + + + align:start position:0% +and when people have a heterozygous it +means they have one good copy of the + + align:start position:0% +means they have one good copy of the + + + align:start position:0% +means they have one good copy of the +gene that's normal and the copy of the + + align:start position:0% +gene that's normal and the copy of the + + + align:start position:0% +gene that's normal and the copy of the +gene that's the variant and you'll learn + + align:start position:0% +gene that's the variant and you'll learn + + + align:start position:0% +gene that's the variant and you'll learn +much more about this in human genetics + + align:start position:0% +much more about this in human genetics + + + align:start position:0% +much more about this in human genetics +when we talk about that later on so you + + align:start position:0% +when we talk about that later on so you + + + align:start position:0% +when we talk about that later on so you +have a lecture of the okay hemoglobin + + align:start position:0% +have a lecture of the okay hemoglobin + + + align:start position:0% +have a lecture of the okay hemoglobin +and the bad and the sickle cell + + align:start position:0% +and the bad and the sickle cell + + + align:start position:0% +and the bad and the sickle cell +hemoglobin people who are homozygous for + + align:start position:0% +hemoglobin people who are homozygous for + + + align:start position:0% +hemoglobin people who are homozygous for +the defect all of their hemoglobin is is + + align:start position:0% +the defect all of their hemoglobin is is + + + align:start position:0% +the defect all of their hemoglobin is is +disrupted and those are the people who + + align:start position:0% +disrupted and those are the people who + + + align:start position:0% +disrupted and those are the people who +really end up in hospital with a lot of + + align:start position:0% +really end up in hospital with a lot of + + + align:start position:0% +really end up in hospital with a lot of +transfusions and so on + + align:start position:0% +transfusions and so on + + + align:start position:0% +transfusions and so on +the heterozygous actually you can manage + + align:start position:0% +the heterozygous actually you can manage + + + align:start position:0% +the heterozygous actually you can manage +quite well with and I'm going to show + + align:start position:0% +quite well with and I'm going to show + + + align:start position:0% +quite well with and I'm going to show +you in a minute that in some parts of + + align:start position:0% +you in a minute that in some parts of + + + align:start position:0% +you in a minute that in some parts of +the world being heterozygous I having + + align:start position:0% +the world being heterozygous I having + + + align:start position:0% +the world being heterozygous I having +some of your hemoglobin with the defect + + align:start position:0% +some of your hemoglobin with the defect + + + align:start position:0% +some of your hemoglobin with the defect +and some without it actually comes with + + align:start position:0% +and some without it actually comes with + + + align:start position:0% +and some without it actually comes with +an advantage it's a really cool story + + align:start position:0% +an advantage it's a really cool story + + + align:start position:0% +an advantage it's a really cool story +okay so what I'm going to do is quickly + + align:start position:0% +okay so what I'm going to do is quickly + + + align:start position:0% +okay so what I'm going to do is quickly +show you the wire structure okay so this + + align:start position:0% +show you the wire structure okay so this + + + align:start position:0% +show you the wire structure okay so this +is the structure that elucidated the + + align:start position:0% +is the structure that elucidated the + + + align:start position:0% +is the structure that elucidated the +real reason for this for the the + + align:start position:0% +real reason for this for the the + + + align:start position:0% +real reason for this for the the +interaction what happens when you have + + align:start position:0% +interaction what happens when you have + + + align:start position:0% +interaction what happens when you have +this mutation okay and it was a + + align:start position:0% +this mutation okay and it was a + + + align:start position:0% +this mutation okay and it was a +structure that was captured of a dimer + + align:start position:0% +structure that was captured of a dimer + + + align:start position:0% +structure that was captured of a dimer +of hemoglobin molecules where you + + align:start position:0% +of hemoglobin molecules where you + + + align:start position:0% +of hemoglobin molecules where you +really see what was happening at the + + align:start position:0% +really see what was happening at the + + + align:start position:0% +really see what was happening at the +interface and the sorts of changes that + + align:start position:0% +interface and the sorts of changes that + + + align:start position:0% +interface and the sorts of changes that +have been put in place by that variation + + align:start position:0% +have been put in place by that variation + + + align:start position:0% +have been put in place by that variation +from the charged to the neutral + + align:start position:0% +from the charged to the neutral + + + align:start position:0% +from the charged to the neutral +structure so for any of you who want to + + align:start position:0% +structure so for any of you who want to + + + align:start position:0% +structure so for any of you who want to +pop by I can start to show you how to + + align:start position:0% +pop by I can start to show you how to + + + align:start position:0% +pop by I can start to show you how to +manipulate pi mol we can do that + + align:start position:0% +manipulate pi mol we can do that + + + align:start position:0% +manipulate pi mol we can do that +separately from class but this is a + + align:start position:0% +separately from class but this is a + + + align:start position:0% +separately from class but this is a +dimer of tetramers and if I just show + + align:start position:0% +dimer of tetramers and if I just show + + + align:start position:0% +dimer of tetramers and if I just show +you just some of the subunits I can + + align:start position:0% +you just some of the subunits I can + + + align:start position:0% +you just some of the subunits I can +actually show you how there's two of + + align:start position:0% +actually show you how there's two of + + + align:start position:0% +actually show you how there's two of +each subunit in each structure so if I + + align:start position:0% +each subunit in each structure so if I + + + align:start position:0% +each subunit in each structure so if I +go I can pick some out every other 1g + + align:start position:0% +go I can pick some out every other 1g + + + align:start position:0% +go I can pick some out every other 1g +and then I can color them a different + + align:start position:0% +and then I can color them a different + + + align:start position:0% +and then I can color them a different +color you can see where the globins + + align:start position:0% +color you can see where the globins + + + align:start position:0% +color you can see where the globins +where the beta globin czar and where the + + align:start position:0% +where the beta globin czar and where the + + + align:start position:0% +where the beta globin czar and where the +alpha globin czar that still looks like + + align:start position:0% +alpha globin czar that still looks like + + + align:start position:0% +alpha globin czar that still looks like +chicken wire it's very unsatisfactory so + + align:start position:0% +chicken wire it's very unsatisfactory so + + + align:start position:0% +chicken wire it's very unsatisfactory so +what I can do is I can show you + + align:start position:0% +what I can do is I can show you + + + align:start position:0% +what I can do is I can show you +everything as a cartoon and get rid of + + align:start position:0% +everything as a cartoon and get rid of + + + align:start position:0% +everything as a cartoon and get rid of +all those little lines and then you can + + align:start position:0% +all those little lines and then you can + + + align:start position:0% +all those little lines and then you can +see perfectly the to the structure where + + align:start position:0% +see perfectly the to the structure where + + + align:start position:0% +see perfectly the to the structure where +you see two beta globin z' and two alpha + + align:start position:0% +you see two beta globin z' and two alpha + + + align:start position:0% +you see two beta globin z' and two alpha +globin x' in each structure okay so what + + align:start position:0% +globin x' in each structure okay so what + + + align:start position:0% +globin x' in each structure okay so what +we're gonna do next is zoom in to see + + align:start position:0% +we're gonna do next is zoom in to see + + + align:start position:0% +we're gonna do next is zoom in to see +what's happening where we've done this + + align:start position:0% +what's happening where we've done this + + + align:start position:0% +what's happening where we've done this +mutation what's going on with the + + align:start position:0% +mutation what's going on with the + + + align:start position:0% +mutation what's going on with the +placement of the baleen in that + + align:start position:0% +placement of the baleen in that + + + align:start position:0% +placement of the baleen in that +structure all right and wherever I put a + + align:start position:0% +structure all right and wherever I put a + + + align:start position:0% +structure all right and wherever I put a +fork four letter code so that one was + + align:start position:0% +fork four letter code so that one was + + + align:start position:0% +fork four letter code so that one was +two HBS that's what's known as the + + align:start position:0% +two HBS that's what's known as the + + + align:start position:0% +two HBS that's what's known as the +protein databank code and it enables you + + align:start position:0% +protein databank code and it enables you + + + align:start position:0% +protein databank code and it enables you +to go fetch the coordinates of that + + align:start position:0% +to go fetch the coordinates of that + + + align:start position:0% +to go fetch the coordinates of that +protein so if any of you for the late + + align:start position:0% +protein so if any of you for the late + + + align:start position:0% +protein so if any of you for the late +project want to do a protein structure + + align:start position:0% +project want to do a protein structure + + + align:start position:0% +project want to do a protein structure +and print it come to me and I'll explain + + align:start position:0% +and print it come to me and I'll explain + + + align:start position:0% +and print it come to me and I'll explain +a lot more about that or all the TAS can + + align:start position:0% +a lot more about that or all the TAS can + + + align:start position:0% +a lot more about that or all the TAS can +also do that so let me now move you to + + align:start position:0% +also do that so let me now move you to + + + align:start position:0% +also do that so let me now move you to +looking in closely to the variations so + + align:start position:0% +looking in closely to the variations so + + + align:start position:0% +looking in closely to the variations so +what I've done here is I've actually + + align:start position:0% +what I've done here is I've actually + + + align:start position:0% +what I've done here is I've actually +colored the beta globin spurple and the + + align:start position:0% +colored the beta globin spurple and the + + + align:start position:0% +colored the beta globin spurple and the +Alpha globin is a cyan colored you can + + align:start position:0% +Alpha globin is a cyan colored you can + + + align:start position:0% +Alpha globin is a cyan colored you can +see the hems in each of the subunits + + align:start position:0% +see the hems in each of the subunits + + + align:start position:0% +see the hems in each of the subunits +those are those red wire things and now + + align:start position:0% +those are those red wire things and now + + + align:start position:0% +those are those red wire things and now +we've zoomed in to the place where the + + align:start position:0% +we've zoomed in to the place where the + + + align:start position:0% +we've zoomed in to the place where the +mutation is where you have a baleen + + align:start position:0% +mutation is where you have a baleen + + + align:start position:0% +mutation is where you have a baleen +instead of a carboxylic acid + + align:start position:0% +instead of a carboxylic acid + + + align:start position:0% +instead of a carboxylic acid +and what you can see from this image + + align:start position:0% +and what you can see from this image + + + align:start position:0% +and what you can see from this image +which should stop is that the baleen on + + align:start position:0% +which should stop is that the baleen on + + + align:start position:0% +which should stop is that the baleen on +one subunit in one homo tetramer + + align:start position:0% +one subunit in one homo tetramer + + + align:start position:0% +one subunit in one homo tetramer +interacts with a sticky patch on another + + align:start position:0% +interacts with a sticky patch on another + + + align:start position:0% +interacts with a sticky patch on another +subunit that's made up of phenylalanine + + align:start position:0% +subunit that's made up of phenylalanine + + + align:start position:0% +subunit that's made up of phenylalanine +85 in the adjacent protein and leucine + + align:start position:0% +85 in the adjacent protein and leucine + + + align:start position:0% +85 in the adjacent protein and leucine +88 in the adjacent protein so this + + align:start position:0% +88 in the adjacent protein so this + + + align:start position:0% +88 in the adjacent protein so this +sticky patch on one surface glues on to + + align:start position:0% +sticky patch on one surface glues on to + + + align:start position:0% +sticky patch on one surface glues on to +a sticky patch on the surface of another + + align:start position:0% +a sticky patch on the surface of another + + + align:start position:0% +a sticky patch on the surface of another +tetra mer if you had glutamic glutamate + + align:start position:0% +tetra mer if you had glutamic glutamate + + + align:start position:0% +tetra mer if you had glutamic glutamate +there would that form no in fact it + + align:start position:0% +there would that form no in fact it + + + align:start position:0% +there would that form no in fact it +would be quite deterred from forming + + align:start position:0% +would be quite deterred from forming + + + align:start position:0% +would be quite deterred from forming +because you don't want to cram that + + align:start position:0% +because you don't want to cram that + + + align:start position:0% +because you don't want to cram that +negatively charged element into those + + align:start position:0% +negatively charged element into those + + + align:start position:0% +negatively charged element into those +two hydrophobic residues so what you've + + align:start position:0% +two hydrophobic residues so what you've + + + align:start position:0% +two hydrophobic residues so what you've +gone from is a situation where this + + align:start position:0% +gone from is a situation where this + + + align:start position:0% +gone from is a situation where this +really is fine on a surface it's + + align:start position:0% +really is fine on a surface it's + + + align:start position:0% +really is fine on a surface it's +hydrated it's not sticking to anything + + align:start position:0% +hydrated it's not sticking to anything + + + align:start position:0% +hydrated it's not sticking to anything +to another situation where you have + + align:start position:0% +to another situation where you have + + + align:start position:0% +to another situation where you have +phenylalanine and leucine which are both + + align:start position:0% +phenylalanine and leucine which are both + + + align:start position:0% +phenylalanine and leucine which are both +hydrophobic providing a catch on the one + + align:start position:0% +hydrophobic providing a catch on the one + + + align:start position:0% +hydrophobic providing a catch on the one +tetramer where the the valine from the + + align:start position:0% +tetramer where the the valine from the + + + align:start position:0% +tetramer where the the valine from the +other tetramer combined and because the + + align:start position:0% +other tetramer combined and because the + + + align:start position:0% +other tetramer combined and because the +molecules are tetra mer on each of the + + align:start position:0% +molecules are tetra mer on each of the + + + align:start position:0% +molecules are tetra mer on each of the +subunits there is also another valine + + align:start position:0% +subunits there is also another valine + + + align:start position:0% +subunits there is also another valine +that will go off and do that elsewhere + + align:start position:0% +that will go off and do that elsewhere + + + align:start position:0% +that will go off and do that elsewhere +and another valine and there's one you + + align:start position:0% +and another valine and there's one you + + + align:start position:0% +and another valine and there's one you +can't see that's tucked behind so that's + + align:start position:0% +can't see that's tucked behind so that's + + + align:start position:0% +can't see that's tucked behind so that's +why the hemoglobin forms these + + align:start position:0% +why the hemoglobin forms these + + + align:start position:0% +why the hemoglobin forms these +structures because every hemoglobin + + align:start position:0% +structures because every hemoglobin + + + align:start position:0% +structures because every hemoglobin +molecule has two places to stick to + + align:start position:0% +molecule has two places to stick to + + + align:start position:0% +molecule has two places to stick to +another hemoglobin tetra mer and so on + + align:start position:0% +another hemoglobin tetra mer and so on + + + align:start position:0% +another hemoglobin tetra mer and so on +so think of the repercussions from one + + align:start position:0% +so think of the repercussions from one + + + align:start position:0% +so think of the repercussions from one +nucleic acid change that's really quite + + align:start position:0% +nucleic acid change that's really quite + + + align:start position:0% +nucleic acid change that's really quite +remarkable so what we've seen here is + + align:start position:0% +remarkable so what we've seen here is + + + align:start position:0% +remarkable so what we've seen here is +that that change occurs so just just a + + align:start position:0% +that that change occurs so just just a + + + align:start position:0% +that that change occurs so just just a +couple of moments for you to think about + + align:start position:0% +couple of moments for you to think about + + + align:start position:0% +couple of moments for you to think about +this you can have variations at that + + align:start position:0% +this you can have variations at that + + + align:start position:0% +this you can have variations at that +site that won't cause a problem which + + align:start position:0% +site that won't cause a problem which + + + align:start position:0% +site that won't cause a problem which +ones of these do you think at least + + align:start position:0% +ones of these do you think at least + + + align:start position:0% +ones of these do you think at least +likely to cause a sickle cell type of + + align:start position:0% +likely to cause a sickle cell type of + + + align:start position:0% +likely to cause a sickle cell type of +phenomenon so tyrosine serine aspartic + + align:start position:0% +phenomenon so tyrosine serine aspartic + + + align:start position:0% +phenomenon so tyrosine serine aspartic +acid and lysine so I'm going to change + + align:start position:0% +acid and lysine so I'm going to change + + + align:start position:0% +acid and lysine so I'm going to change +the glutamate to something else which + + align:start position:0% +the glutamate to something else which + + + align:start position:0% +the glutamate to something else which +one's going to have a perfectly normal + + align:start position:0% +one's going to have a perfectly normal + + + align:start position:0% +one's going to have a perfectly normal +hemoglobin there's one that stands out + + align:start position:0% +hemoglobin there's one that stands out + + + align:start position:0% +hemoglobin there's one that stands out +yeah aspartic that's fine no problem it + + align:start position:0% +yeah aspartic that's fine no problem it + + + align:start position:0% +yeah aspartic that's fine no problem it +just switched it for her it's younger + + align:start position:0% +just switched it for her it's younger + + + align:start position:0% +just switched it for her it's younger +brother wait which one of the others and + + align:start position:0% +brother wait which one of the others and + + + align:start position:0% +brother wait which one of the others and +and in many cases here you could + + align:start position:0% +and in many cases here you could + + + align:start position:0% +and in many cases here you could +probably argue your way to all of them + + align:start position:0% +probably argue your way to all of them + + + align:start position:0% +probably argue your way to all of them +but one would be pretty bad which one + + align:start position:0% +but one would be pretty bad which one + + + align:start position:0% +but one would be pretty bad which one +would be pretty bad + + align:start position:0% + + + + align:start position:0% + +tyrosine exactly it's another even + + align:start position:0% +tyrosine exactly it's another even + + + align:start position:0% +tyrosine exactly it's another even +though it's got that Oh H group it's + + align:start position:0% +though it's got that Oh H group it's + + + align:start position:0% +though it's got that Oh H group it's +still pretty hydrophobic because of that + + align:start position:0% +still pretty hydrophobic because of that + + + align:start position:0% +still pretty hydrophobic because of that +ring system there what about the other + + align:start position:0% +ring system there what about the other + + + align:start position:0% +ring system there what about the other +two serine and lysine what do you think + + align:start position:0% +two serine and lysine what do you think + + + align:start position:0% +two serine and lysine what do you think +which one would probably be in fact the + + align:start position:0% +which one would probably be in fact the + + + align:start position:0% +which one would probably be in fact the +least detrimental of those remaining two + + align:start position:0% +least detrimental of those remaining two + + + align:start position:0% +least detrimental of those remaining two +and give me the reason as well yes + + align:start position:0% +and give me the reason as well yes + + + align:start position:0% +and give me the reason as well yes +lysine I think it would be lysine + + align:start position:0% +lysine I think it would be lysine + + + align:start position:0% +lysine I think it would be lysine +because lysine is now positively charged + + align:start position:0% +because lysine is now positively charged + + + align:start position:0% +because lysine is now positively charged +it's equally unlikely to want to do this + + align:start position:0% +it's equally unlikely to want to do this + + + align:start position:0% +it's equally unlikely to want to do this +goofy interaction because it is also + + align:start position:0% +goofy interaction because it is also + + + align:start position:0% +goofy interaction because it is also +charged just charged in the other + + align:start position:0% +charged just charged in the other + + + align:start position:0% +charged just charged in the other +direction but one could also argue that + + align:start position:0% +direction but one could also argue that + + + align:start position:0% +direction but one could also argue that +serine would be okay + + align:start position:0% +serine would be okay + + + align:start position:0% +serine would be okay +because it's got it's a little bit more + + align:start position:0% +because it's got it's a little bit more + + + align:start position:0% +because it's got it's a little bit more +not a polar so it wouldn't cause as much + + align:start position:0% +not a polar so it wouldn't cause as much + + + align:start position:0% +not a polar so it wouldn't cause as much +problem okay + + align:start position:0% +problem okay + + + align:start position:0% +problem okay +finally the this issue with sickle cell + + align:start position:0% +finally the this issue with sickle cell + + + align:start position:0% +finally the this issue with sickle cell +anemia there's some fascinating data + + align:start position:0% +anemia there's some fascinating data + + + align:start position:0% +anemia there's some fascinating data +that shows in parts of the world for + + align:start position:0% +that shows in parts of the world for + + + align:start position:0% +that shows in parts of the world for +example during a drug trial for + + align:start position:0% +example during a drug trial for + + + align:start position:0% +example during a drug trial for +Plasmodium falciparum one of the + + align:start position:0% +Plasmodium falciparum one of the + + + align:start position:0% +Plasmodium falciparum one of the +causative agents of malaria they found + + align:start position:0% +causative agents of malaria they found + + + align:start position:0% +causative agents of malaria they found +that one out of 15 people with the + + align:start position:0% +that one out of 15 people with the + + + align:start position:0% +that one out of 15 people with the +sickle-cell trait was infected with + + align:start position:0% +sickle-cell trait was infected with + + + align:start position:0% +sickle-cell trait was infected with +malaria whereas the the people who were + + align:start position:0% +malaria whereas the the people who were + + + align:start position:0% +malaria whereas the the people who were +healthy normal homozygous for the right + + align:start position:0% +healthy normal homozygous for the right + + + align:start position:0% +healthy normal homozygous for the right +hemoglobin 14 out of 15 were infected + + align:start position:0% +hemoglobin 14 out of 15 were infected + + + align:start position:0% +hemoglobin 14 out of 15 were infected +with Plasmodium falciparum and now what + + align:start position:0% +with Plasmodium falciparum and now what + + + align:start position:0% +with Plasmodium falciparum and now what +do you think why do you think that is + + align:start position:0% +do you think why do you think that is + + + align:start position:0% +do you think why do you think that is +how can we relate the infectivity of a + + align:start position:0% +how can we relate the infectivity of a + + + align:start position:0% +how can we relate the infectivity of a +parasite with the shape of a cell we've + + align:start position:0% +parasite with the shape of a cell we've + + + align:start position:0% +parasite with the shape of a cell we've +gone from these juicy looking red blood + + align:start position:0% +gone from these juicy looking red blood + + + align:start position:0% +gone from these juicy looking red blood +cells nice and round and probably quite + + align:start position:0% +cells nice and round and probably quite + + + align:start position:0% +cells nice and round and probably quite +open to a cell that sort of difficult + + align:start position:0% +open to a cell that sort of difficult + + + align:start position:0% +open to a cell that sort of difficult +shape so it turns out that the parasite + + align:start position:0% +shape so it turns out that the parasite + + + align:start position:0% +shape so it turns out that the parasite +doesn't want to infect the sickle cells + + align:start position:0% +doesn't want to infect the sickle cells + + + align:start position:0% +doesn't want to infect the sickle cells +that cells red blood cells anywhere near + + align:start position:0% +that cells red blood cells anywhere near + + + align:start position:0% +that cells red blood cells anywhere near +as well and there are for example other + + align:start position:0% +as well and there are for example other + + + align:start position:0% +as well and there are for example other +Bloods tested which shows the same + + align:start position:0% +Bloods tested which shows the same + + + align:start position:0% +Bloods tested which shows the same +correlation + + align:start position:0% +correlation + + + align:start position:0% +correlation +and here's a map of Africa where you see + + align:start position:0% +and here's a map of Africa where you see + + + align:start position:0% +and here's a map of Africa where you see +a massive overlap of the prevalence of + + align:start position:0% +a massive overlap of the prevalence of + + + align:start position:0% +a massive overlap of the prevalence of +the sickle cell trait and the and the + + align:start position:0% +the sickle cell trait and the and the + + + align:start position:0% +the sickle cell trait and the and the +presence of Plasmodium falciparum so + + align:start position:0% +presence of Plasmodium falciparum so + + + align:start position:0% +presence of Plasmodium falciparum so +there's there's there is a evolutionary + + align:start position:0% +there's there's there is a evolutionary + + + align:start position:0% +there's there's there is a evolutionary +advantage to having the heterozygous + + align:start position:0% +advantage to having the heterozygous + + + align:start position:0% +advantage to having the heterozygous +variant where you have some normal + + align:start position:0% +variant where you have some normal + + + align:start position:0% +variant where you have some normal +hemoglobin but some of the sickling + + align:start position:0% +hemoglobin but some of the sickling + + + align:start position:0% +hemoglobin but some of the sickling +hemoglobin because it confers you some + + align:start position:0% +hemoglobin because it confers you some + + + align:start position:0% +hemoglobin because it confers you some +resistance to term to malaria it's not + + align:start position:0% +resistance to term to malaria it's not + + + align:start position:0% +resistance to term to malaria it's not +good to have both of them the variant + + align:start position:0% +good to have both of them the variant + + + align:start position:0% +good to have both of them the variant +that causes sickling because that's + + align:start position:0% +that causes sickling because that's + + + align:start position:0% +that causes sickling because that's +painful and it really causes a lot of + + align:start position:0% +painful and it really causes a lot of + + + align:start position:0% +painful and it really causes a lot of +health disorders it's just when you have + + align:start position:0% +health disorders it's just when you have + + + align:start position:0% +health disorders it's just when you have +one of each gene encoding both variants + + align:start position:0% +one of each gene encoding both variants + + + align:start position:0% +one of each gene encoding both variants +okay all right great okay so now we're + + align:start position:0% +okay all right great okay so now we're + + + align:start position:0% +okay all right great okay so now we're +gonna talk about enzymes and these are + + align:start position:0% +gonna talk about enzymes and these are + + + align:start position:0% +gonna talk about enzymes and these are +the proteins that catalyze reactions any + + align:start position:0% +the proteins that catalyze reactions any + + + align:start position:0% +the proteins that catalyze reactions any +questions about that so while a lot of + + align:start position:0% +questions about that so while a lot of + + + align:start position:0% +questions about that so while a lot of +disease states actually might be bred + + align:start position:0% +disease states actually might be bred + + + align:start position:0% +disease states actually might be bred +out because someone would have be at a + + align:start position:0% +out because someone would have be at a + + + align:start position:0% +out because someone would have be at a +disadvantage + + align:start position:0% +disadvantage + + + align:start position:0% +disadvantage +with a particular disease in this case + + align:start position:0% +with a particular disease in this case + + + align:start position:0% +with a particular disease in this case +that trait has been maintained because + + align:start position:0% +that trait has been maintained because + + + align:start position:0% +that trait has been maintained because +it offers a very different advantage + + align:start position:0% +it offers a very different advantage + + + align:start position:0% +it offers a very different advantage +with respect to disease okay let's talk + + align:start position:0% +with respect to disease okay let's talk + + + align:start position:0% +with respect to disease okay let's talk +about enzymes for a moment all for the + + align:start position:0% +about enzymes for a moment all for the + + + align:start position:0% +about enzymes for a moment all for the +rest of the class in fact okay so + + align:start position:0% +rest of the class in fact okay so + + + align:start position:0% +rest of the class in fact okay so +enzymes are the heavy lifters of the + + align:start position:0% +enzymes are the heavy lifters of the + + + align:start position:0% +enzymes are the heavy lifters of the +protein world because they catalyze all + + align:start position:0% +protein world because they catalyze all + + + align:start position:0% +protein world because they catalyze all +the reactions in metabolism in + + align:start position:0% +the reactions in metabolism in + + + align:start position:0% +the reactions in metabolism in +biosynthesis all kinds of + + align:start position:0% +biosynthesis all kinds of + + + align:start position:0% +biosynthesis all kinds of +transformations that make you what you + + align:start position:0% +transformations that make you what you + + + align:start position:0% +transformations that make you what you +are enzymes a protein based catalysts + + align:start position:0% +are enzymes a protein based catalysts + + + align:start position:0% +are enzymes a protein based catalysts +you will know that writing again there + + align:start position:0% +you will know that writing again there + + + align:start position:0% +you will know that writing again there +were a couple of other terms I just + + align:start position:0% +were a couple of other terms I just + + + align:start position:0% +were a couple of other terms I just +quickly want to give you so an enzyme + + align:start position:0% +quickly want to give you so an enzyme + + + align:start position:0% +quickly want to give you so an enzyme +there's also a term known as an ISO xym + + align:start position:0% +there's also a term known as an ISO xym + + + align:start position:0% +there's also a term known as an ISO xym +and an allison you may see them you'll + + align:start position:0% +and an allison you may see them you'll + + + align:start position:0% +and an allison you may see them you'll +see Alice + + align:start position:0% +see Alice + + + align:start position:0% +see Alice +less commonly but you'll see Isis I'm + + align:start position:0% +less commonly but you'll see Isis I'm + + + align:start position:0% +less commonly but you'll see Isis I'm +quite commonly an Isis I'm of one enzyme + + align:start position:0% +quite commonly an Isis I'm of one enzyme + + + align:start position:0% +quite commonly an Isis I'm of one enzyme +is a variation on the enzyme that + + align:start position:0% +is a variation on the enzyme that + + + align:start position:0% +is a variation on the enzyme that +catalyzes the same reaction but it's + + align:start position:0% +catalyzes the same reaction but it's + + + align:start position:0% +catalyzes the same reaction but it's +expressed on a different gene an aloes + + align:start position:0% +expressed on a different gene an aloes + + + align:start position:0% +expressed on a different gene an aloes +I'm is the same enzyme but with a + + align:start position:0% +I'm is the same enzyme but with a + + + align:start position:0% +I'm is the same enzyme but with a +variation in it so it's it's encoded by + + align:start position:0% +variation in it so it's it's encoded by + + + align:start position:0% +variation in it so it's it's encoded by +an allele of one gene so there it's just + + align:start position:0% +an allele of one gene so there it's just + + + align:start position:0% +an allele of one gene so there it's just +a variation of the gene that might have + + align:start position:0% +a variation of the gene that might have + + + align:start position:0% +a variation of the gene that might have +happened through a mutation still + + align:start position:0% +happened through a mutation still + + + align:start position:0% +happened through a mutation still +catalyzes the reaction but there's a + + align:start position:0% +catalyzes the reaction but there's a + + + align:start position:0% +catalyzes the reaction but there's a +change in slight change in the sequence + + align:start position:0% +change in slight change in the sequence + + + align:start position:0% +change in slight change in the sequence +but they're coded by the same gene same + + align:start position:0% +but they're coded by the same gene same + + + align:start position:0% +but they're coded by the same gene same +gene with a variation and as I said you + + align:start position:0% +gene with a variation and as I said you + + + align:start position:0% +gene with a variation and as I said you +will see the isozyme term more commonly + + align:start position:0% +will see the isozyme term more commonly + + + align:start position:0% +will see the isozyme term more commonly +than the al Azim term now why do we need + + align:start position:0% +than the al Azim term now why do we need + + + align:start position:0% +than the al Azim term now why do we need +enzymes well the problem is there are + + align:start position:0% +enzymes well the problem is there are + + + align:start position:0% +enzymes well the problem is there are +reactions physiologic reactions that we + + align:start position:0% +reactions physiologic reactions that we + + + align:start position:0% +reactions physiologic reactions that we +need to carry out that are just too hard + + align:start position:0% +need to carry out that are just too hard + + + align:start position:0% +need to carry out that are just too hard +to carry out at room temperature pH 7 in + + align:start position:0% +to carry out at room temperature pH 7 in + + + align:start position:0% +to carry out at room temperature pH 7 in +water they just don't occur so you need + + align:start position:0% +water they just don't occur so you need + + + align:start position:0% +water they just don't occur so you need +enzyme catalysis for all of your + + align:start position:0% +enzyme catalysis for all of your + + + align:start position:0% +enzyme catalysis for all of your +metabolic reactions let me just give you + + align:start position:0% +metabolic reactions let me just give you + + + align:start position:0% +metabolic reactions let me just give you +one trivial example this bond really no + + align:start position:0% +one trivial example this bond really no + + + align:start position:0% +one trivial example this bond really no +nicely now peptide or amide bond if I + + align:start position:0% +nicely now peptide or amide bond if I + + + align:start position:0% +nicely now peptide or amide bond if I +want to hydrolyze that if I want to + + align:start position:0% +want to hydrolyze that if I want to + + + align:start position:0% +want to hydrolyze that if I want to +break it open pH 7 physiologic + + align:start position:0% +break it open pH 7 physiologic + + + align:start position:0% +break it open pH 7 physiologic +temperatures so 37 see you know in water + + align:start position:0% +temperatures so 37 see you know in water + + + align:start position:0% +temperatures so 37 see you know in water +it would take me how many years is it + + align:start position:0% +it would take me how many years is it + + + align:start position:0% +it would take me how many years is it +the half-life of that bond would be 600 + + align:start position:0% +the half-life of that bond would be 600 + + + align:start position:0% +the half-life of that bond would be 600 +years okay there and that's pretty + + align:start position:0% +years okay there and that's pretty + + + align:start position:0% +years okay there and that's pretty +untenable for digesting a Big Mac even + + align:start position:0% +untenable for digesting a Big Mac even + + + align:start position:0% +untenable for digesting a Big Mac even +even under the best of circumstances + + align:start position:0% +even under the best of circumstances + + + align:start position:0% +even under the best of circumstances +right so we + + align:start position:0% +right so we + + + align:start position:0% +right so we +need enzymes to speed up breaking down + + align:start position:0% +need enzymes to speed up breaking down + + + align:start position:0% +need enzymes to speed up breaking down +proteins carrying out reactions because + + align:start position:0% +proteins carrying out reactions because + + + align:start position:0% +proteins carrying out reactions because +otherwise we just can't we can't do + + align:start position:0% +otherwise we just can't we can't do + + + align:start position:0% +otherwise we just can't we can't do +anything so what I want to describe to + + align:start position:0% +anything so what I want to describe to + + + align:start position:0% +anything so what I want to describe to +you some of the details of how enzymes + + align:start position:0% +you some of the details of how enzymes + + + align:start position:0% +you some of the details of how enzymes +work and then how we can control the + + align:start position:0% +work and then how we can control the + + + align:start position:0% +work and then how we can control the +function of enzymes so typical enzymes + + align:start position:0% +function of enzymes so typical enzymes + + + align:start position:0% +function of enzymes so typical enzymes +take a substrate to a product some + + align:start position:0% +take a substrate to a product some + + + align:start position:0% +take a substrate to a product some +enzymes may take two substrates and make + + align:start position:0% +enzymes may take two substrates and make + + + align:start position:0% +enzymes may take two substrates and make +one product some enzymes may we take one + + align:start position:0% +one product some enzymes may we take one + + + align:start position:0% +one product some enzymes may we take one +substrate and make two products it just + + align:start position:0% +substrate and make two products it just + + + align:start position:0% +substrate and make two products it just +depends on the transformation that + + align:start position:0% +depends on the transformation that + + + align:start position:0% +depends on the transformation that +you're doing enzymes are classified into + + align:start position:0% +you're doing enzymes are classified into + + + align:start position:0% +you're doing enzymes are classified into +a bunch of different families but the + + align:start position:0% +a bunch of different families but the + + + align:start position:0% +a bunch of different families but the +thing that will tell you that something + + align:start position:0% +thing that will tell you that something + + + align:start position:0% +thing that will tell you that something +you're reading about is an enzyme is the + + align:start position:0% +you're reading about is an enzyme is the + + + align:start position:0% +you're reading about is an enzyme is the +suffix a s e at the end of the name of + + align:start position:0% +suffix a s e at the end of the name of + + + align:start position:0% +suffix a s e at the end of the name of +the enzyme so the enzyme that hydrolyzes + + align:start position:0% +the enzyme so the enzyme that hydrolyzes + + + align:start position:0% +the enzyme so the enzyme that hydrolyzes +the peptide bond or hydrolyzes proteins + + align:start position:0% +the peptide bond or hydrolyzes proteins + + + align:start position:0% +the peptide bond or hydrolyzes proteins +is called no big surprise a protease and + + align:start position:0% +is called no big surprise a protease and + + + align:start position:0% +is called no big surprise a protease and +you'll see later on ribonuclease DNA's + + align:start position:0% +you'll see later on ribonuclease DNA's + + + align:start position:0% +you'll see later on ribonuclease DNA's +oxidoreductases all kinds of rare + + align:start position:0% +oxidoreductases all kinds of rare + + + align:start position:0% +oxidoreductases all kinds of rare +reactions where if you see this term at + + align:start position:0% +reactions where if you see this term at + + + align:start position:0% +reactions where if you see this term at +the end of the name it's telling you + + align:start position:0% +the end of the name it's telling you + + + align:start position:0% +the end of the name it's telling you +quite loud and clear that it's an enzyme + + align:start position:0% +quite loud and clear that it's an enzyme + + + align:start position:0% +quite loud and clear that it's an enzyme +it's just a very sort of simple way of + + align:start position:0% +it's just a very sort of simple way of + + + align:start position:0% +it's just a very sort of simple way of +remembering now now enzymes promote + + align:start position:0% + + + + align:start position:0% + +promote reactions + + align:start position:0% + + + + align:start position:0% + +in order that we can have them carried + + align:start position:0% +in order that we can have them carried + + + align:start position:0% +in order that we can have them carried +out at room temperature but we want to + + align:start position:0% +out at room temperature but we want to + + + align:start position:0% +out at room temperature but we want to +think about how they they carry out + + align:start position:0% +think about how they they carry out + + + align:start position:0% +think about how they they carry out +these changes and transformations what + + align:start position:0% +these changes and transformations what + + + align:start position:0% +these changes and transformations what +is it about the structure of the protein + + align:start position:0% +is it about the structure of the protein + + + align:start position:0% +is it about the structure of the protein +that enables these reactions but the + + align:start position:0% +that enables these reactions but the + + + align:start position:0% +that enables these reactions but the +first thing we have to do is take a look + + align:start position:0% +first thing we have to do is take a look + + + align:start position:0% +first thing we have to do is take a look +and the thermodynamics and kinetics of a + + align:start position:0% +and the thermodynamics and kinetics of a + + + align:start position:0% +and the thermodynamics and kinetics of a +transformation so before I go anywhere + + align:start position:0% +transformation so before I go anywhere + + + align:start position:0% +transformation so before I go anywhere +what I want to do is describe to you how + + align:start position:0% +what I want to do is describe to you how + + + align:start position:0% +what I want to do is describe to you how +enzymes work by thinking about the + + align:start position:0% +enzymes work by thinking about the + + + align:start position:0% +enzymes work by thinking about the +physical parameters that we describe the + + align:start position:0% +physical parameters that we describe the + + + align:start position:0% +physical parameters that we describe the +energetics of a transformation so in in + + align:start position:0% +energetics of a transformation so in in + + + align:start position:0% +energetics of a transformation so in in +thermodynamics you'll know Delta G is + + align:start position:0% +thermodynamics you'll know Delta G is + + + align:start position:0% +thermodynamics you'll know Delta G is +Delta H minus T Delta s and we're really + + align:start position:0% +Delta H minus T Delta s and we're really + + + align:start position:0% +Delta H minus T Delta s and we're really +only gonna worry about one of these + + align:start position:0% +only gonna worry about one of these + + + align:start position:0% +only gonna worry about one of these +terms we're gonna worry about Delta G + + align:start position:0% +terms we're gonna worry about Delta G + + + align:start position:0% +terms we're gonna worry about Delta G +and I'll explain why so Delta G is the + + align:start position:0% +and I'll explain why so Delta G is the + + + align:start position:0% +and I'll explain why so Delta G is the +Gibbs free energy H is the enthalpy T is + + align:start position:0% +Gibbs free energy H is the enthalpy T is + + + align:start position:0% +Gibbs free energy H is the enthalpy T is +the temperature in Kelvin and then s is + + align:start position:0% +the temperature in Kelvin and then s is + + + align:start position:0% +the temperature in Kelvin and then s is +entropy so these are two terms when + + align:start position:0% +entropy so these are two terms when + + + align:start position:0% +entropy so these are two terms when +you're looking at an energy diagram we + + align:start position:0% +you're looking at an energy diagram we + + + align:start position:0% +you're looking at an energy diagram we +generally think about reactions where we + + align:start position:0% +generally think about reactions where we + + + align:start position:0% +generally think about reactions where we +describe the y coordinate as the change + + align:start position:0% +describe the y coordinate as the change + + + align:start position:0% +describe the y coordinate as the change +in Delta G the change in the free energy + + align:start position:0% +in Delta G the change in the free energy + + + align:start position:0% +in Delta G the change in the free energy +and the x coordinate is your reaction + + align:start position:0% +and the x coordinate is your reaction + + + align:start position:0% +and the x coordinate is your reaction +coordinate so in going from a substrate + + align:start position:0% +coordinate so in going from a substrate + + + align:start position:0% +coordinate so in going from a substrate +to a product we generally have a + + align:start position:0% +to a product we generally have a + + + align:start position:0% +to a product we generally have a +situation where we have a substrate at a + + align:start position:0% +situation where we have a substrate at a + + + align:start position:0% +situation where we have a substrate at a +certain energy and then maybe a product + + align:start position:0% +certain energy and then maybe a product + + + align:start position:0% +certain energy and then maybe a product +at a different energy and we're going to + + align:start position:0% +at a different energy and we're going to + + + align:start position:0% +at a different energy and we're going to +talk about the details of that so why do + + align:start position:0% +talk about the details of that so why do + + + align:start position:0% +talk about the details of that so why do +we deal with Gibbs free energy not an + + align:start position:0% +we deal with Gibbs free energy not an + + + align:start position:0% +we deal with Gibbs free energy not an +enthalpy does anyone know okay + + align:start position:0% +enthalpy does anyone know okay + + + align:start position:0% +enthalpy does anyone know okay +enthalpy describes the energies of + + align:start position:0% +enthalpy describes the energies of + + + align:start position:0% +enthalpy describes the energies of +all the bonds in a molecule but when + + align:start position:0% +all the bonds in a molecule but when + + + align:start position:0% +all the bonds in a molecule but when +you're doing an enzyme catalyzed + + align:start position:0% +you're doing an enzyme catalyzed + + + align:start position:0% +you're doing an enzyme catalyzed +transformation you're not busting open + + align:start position:0% +transformation you're not busting open + + + align:start position:0% +transformation you're not busting open +all of those bonds you're not breaking + + align:start position:0% +all of those bonds you're not breaking + + + align:start position:0% +all of those bonds you're not breaking +something down to carbon hydrogen and + + align:start position:0% +something down to carbon hydrogen and + + + align:start position:0% +something down to carbon hydrogen and +oxygen you're only dealing with parts of + + align:start position:0% +oxygen you're only dealing with parts of + + + align:start position:0% +oxygen you're only dealing with parts of +the energetics of the molecule you're + + align:start position:0% +the energetics of the molecule you're + + + align:start position:0% +the energetics of the molecule you're +only dealing with what's known as the + + align:start position:0% +only dealing with what's known as the + + + align:start position:0% +only dealing with what's known as the +free energy changes to look at the + + align:start position:0% +free energy changes to look at the + + + align:start position:0% +free energy changes to look at the +enthalpy changes isn't going to get you + + align:start position:0% +enthalpy changes isn't going to get you + + + align:start position:0% +enthalpy changes isn't going to get you +very far it's not going to describe the + + align:start position:0% +very far it's not going to describe the + + + align:start position:0% +very far it's not going to describe the +reaction because the enthalpy changes + + align:start position:0% +reaction because the enthalpy changes + + + align:start position:0% +reaction because the enthalpy changes +would be enormous breaking down that + + align:start position:0% +would be enormous breaking down that + + + align:start position:0% +would be enormous breaking down that +molecule and that's not what you want to + + align:start position:0% +molecule and that's not what you want to + + + align:start position:0% +molecule and that's not what you want to +achieve in a chemical transformation we + + align:start position:0% +achieve in a chemical transformation we + + + align:start position:0% +achieve in a chemical transformation we +care about Delta G now the next thing to + + align:start position:0% +care about Delta G now the next thing to + + + align:start position:0% +care about Delta G now the next thing to +think about is what are the energetics + + align:start position:0% +think about is what are the energetics + + + align:start position:0% +think about is what are the energetics +of the reaction and how does an enzyme + + align:start position:0% +of the reaction and how does an enzyme + + + align:start position:0% +of the reaction and how does an enzyme +catalyzed reaction manipulate those n + + align:start position:0% +catalyzed reaction manipulate those n + + + align:start position:0% +catalyzed reaction manipulate those n +energetics so the key thing here is we + + align:start position:0% +energetics so the key thing here is we + + + align:start position:0% +energetics so the key thing here is we +want to talk about Gibbs free energy + + align:start position:0% +want to talk about Gibbs free energy + + + align:start position:0% +want to talk about Gibbs free energy +shouldn't written quite this much stuff + + align:start position:0% +shouldn't written quite this much stuff + + + align:start position:0% +shouldn't written quite this much stuff +here because I need the blackboard + + align:start position:0% +here because I need the blackboard + + + align:start position:0% +here because I need the blackboard +alright so when you describe a reaction + + align:start position:0% +alright so when you describe a reaction + + + align:start position:0% +alright so when you describe a reaction +you want to understand how far that + + align:start position:0% +you want to understand how far that + + + align:start position:0% +you want to understand how far that +reaction goes and how fast that reaction + + align:start position:0% +reaction goes and how fast that reaction + + + align:start position:0% +reaction goes and how fast that reaction +goes so when you go through a reaction + + align:start position:0% +goes so when you go through a reaction + + + align:start position:0% +goes so when you go through a reaction +we can describe how far the reaction + + align:start position:0% +we can describe how far the reaction + + + align:start position:0% +we can describe how far the reaction +goes by thinking about the free energy + + align:start position:0% +goes by thinking about the free energy + + + align:start position:0% +goes by thinking about the free energy +of the substrates and the products so in + + align:start position:0% +of the substrates and the products so in + + + align:start position:0% +of the substrates and the products so in +this case the substrate is at a higher + + align:start position:0% +this case the substrate is at a higher + + + align:start position:0% +this case the substrate is at a higher +energy than the products so you will go + + align:start position:0% +energy than the products so you will go + + + align:start position:0% +energy than the products so you will go +a long way through the reaction to make + + align:start position:0% +a long way through the reaction to make + + + align:start position:0% +a long way through the reaction to make +mud quite a lot of product in there in a + + align:start position:0% +mud quite a lot of product in there in a + + + align:start position:0% +mud quite a lot of product in there in a +transformation so that describes how far + + align:start position:0% +transformation so that describes how far + + + align:start position:0% +transformation so that describes how far +the reaction goes so that is the + + align:start position:0% +the reaction goes so that is the + + + align:start position:0% +the reaction goes so that is the +difference between the energy of the + + align:start position:0% +difference between the energy of the + + + align:start position:0% +difference between the energy of the +substrate and the product how fast the + + align:start position:0% +substrate and the product how fast the + + + align:start position:0% +substrate and the product how fast the +reaction goes concern is described in + + align:start position:0% +reaction goes concern is described in + + + align:start position:0% +reaction goes concern is described in +and didn't different part of this + + align:start position:0% +and didn't different part of this + + + align:start position:0% +and didn't different part of this +diagram does anyone know what it is yes + + align:start position:0% +diagram does anyone know what it is yes + + + align:start position:0% +diagram does anyone know what it is yes +yes exactly how fast the reaction goes + + align:start position:0% +yes exactly how fast the reaction goes + + + align:start position:0% +yes exactly how fast the reaction goes +is literally how high the mountain is + + align:start position:0% +is literally how high the mountain is + + + align:start position:0% +is literally how high the mountain is +but you have to get over + + align:start position:0% +but you have to get over + + + align:start position:0% +but you have to get over +to carry out the transformation and that + + align:start position:0% +to carry out the transformation and that + + + align:start position:0% +to carry out the transformation and that +height is described as the energy of + + align:start position:0% +height is described as the energy of + + + align:start position:0% +height is described as the energy of +activation so that tells you how fast + + align:start position:0% +activation so that tells you how fast + + + align:start position:0% +activation so that tells you how fast +and the difference here tells you how + + align:start position:0% +and the difference here tells you how + + + align:start position:0% +and the difference here tells you how +far the energy of activation is a really + + align:start position:0% +far the energy of activation is a really + + + align:start position:0% +far the energy of activation is a really +important parameter because it's + + align:start position:0% +important parameter because it's + + + align:start position:0% +important parameter because it's +actually what gets manipulated when + + align:start position:0% +actually what gets manipulated when + + + align:start position:0% +actually what gets manipulated when +you're dealing with catalyzed reactions + + align:start position:0% +you're dealing with catalyzed reactions + + + align:start position:0% +you're dealing with catalyzed reactions +so the energy of activation the higher + + align:start position:0% +so the energy of activation the higher + + + align:start position:0% +so the energy of activation the higher +that mountain is the slower the reaction + + align:start position:0% +that mountain is the slower the reaction + + + align:start position:0% +that mountain is the slower the reaction +will be because it's a much harder + + align:start position:0% +will be because it's a much harder + + + align:start position:0% +will be because it's a much harder +transformation to go through the + + align:start position:0% +transformation to go through the + + + align:start position:0% +transformation to go through the +reactions in our bodies can be of + + align:start position:0% +reactions in our bodies can be of + + + align:start position:0% +reactions in our bodies can be of +different flavors depending on the + + align:start position:0% +different flavors depending on the + + + align:start position:0% +different flavors depending on the +difference in energy of the substrate + + align:start position:0% +difference in energy of the substrate + + + align:start position:0% +difference in energy of the substrate +and the product so shown there substrate + + align:start position:0% +and the product so shown there substrate + + + align:start position:0% +and the product so shown there substrate +going to products where the product is + + align:start position:0% +going to products where the product is + + + align:start position:0% +going to products where the product is +at lower energy than the substrate we + + align:start position:0% +at lower energy than the substrate we + + + align:start position:0% +at lower energy than the substrate we +would call this an exergonic reaction + + align:start position:0% +would call this an exergonic reaction + + + align:start position:0% +would call this an exergonic reaction +because we're releasing energy in the in + + align:start position:0% +because we're releasing energy in the in + + + align:start position:0% +because we're releasing energy in the in +the transformation so as higher than P + + align:start position:0% +the transformation so as higher than P + + + align:start position:0% +the transformation so as higher than P +exergonic and if we have a different + + align:start position:0% +exergonic and if we have a different + + + align:start position:0% +exergonic and if we have a different +reaction and I'll sketch this one in + + align:start position:0% +reaction and I'll sketch this one in + + + align:start position:0% +reaction and I'll sketch this one in +here where the product is higher energy + + align:start position:0% +here where the product is higher energy + + + align:start position:0% +here where the product is higher energy +and this is a reaction coordinate then + + align:start position:0% +and this is a reaction coordinate then + + + align:start position:0% +and this is a reaction coordinate then +that will be an endergonic reaction both + + align:start position:0% +that will be an endergonic reaction both + + + align:start position:0% +that will be an endergonic reaction both +reactions happen in the enzyme catalyzed + + align:start position:0% +reactions happen in the enzyme catalyzed + + + align:start position:0% +reactions happen in the enzyme catalyzed +systems and we'll explain why you're + + align:start position:0% +systems and we'll explain why you're + + + align:start position:0% +systems and we'll explain why you're +able to catalyze even ones that require + + align:start position:0% +able to catalyze even ones that require + + + align:start position:0% +able to catalyze even ones that require +energy so exergonic releases energy + + align:start position:0% + + + + align:start position:0% + +and endergonic requires okay what else + + align:start position:0% +and endergonic requires okay what else + + + align:start position:0% +and endergonic requires okay what else +have I got on here we also in the + + align:start position:0% +have I got on here we also in the + + + align:start position:0% +have I got on here we also in the +situations where energy is produced the + + align:start position:0% +situations where energy is produced the + + + align:start position:0% +situations where energy is produced the +exergonic reactions we call these + + align:start position:0% +exergonic reactions we call these + + + align:start position:0% +exergonic reactions we call these +catabolic processes and if you have + + align:start position:0% +catabolic processes and if you have + + + align:start position:0% +catabolic processes and if you have +trouble remembering catabolic and + + align:start position:0% +trouble remembering catabolic and + + + align:start position:0% +trouble remembering catabolic and +anabolic just join me in that because I + + align:start position:0% +anabolic just join me in that because I + + + align:start position:0% +anabolic just join me in that because I +always forget which is which but the + + align:start position:0% +always forget which is which but the + + + align:start position:0% +always forget which is which but the +ones that produce energy a catabolic the + + align:start position:0% +ones that produce energy a catabolic the + + + align:start position:0% +ones that produce energy a catabolic the +ones that require energy are anabolic + + align:start position:0% +ones that require energy are anabolic + + + align:start position:0% +ones that require energy are anabolic +and when we think about metabolism the + + align:start position:0% +and when we think about metabolism the + + + align:start position:0% +and when we think about metabolism the +catabolic reactions are when we're + + align:start position:0% +catabolic reactions are when we're + + + align:start position:0% +catabolic reactions are when we're +breaking molecules down because we need + + align:start position:0% +breaking molecules down because we need + + + align:start position:0% +breaking molecules down because we need +energy we need to use it to do something + + align:start position:0% +energy we need to use it to do something + + + align:start position:0% +energy we need to use it to do something +the anabolic reactions are when we want + + align:start position:0% +the anabolic reactions are when we want + + + align:start position:0% +the anabolic reactions are when we want +to store things store fats build + + align:start position:0% +to store things store fats build + + + align:start position:0% +to store things store fats build +proteins because they're going to be + + align:start position:0% +proteins because they're going to be + + + align:start position:0% +proteins because they're going to be +endergonic they're going to be requiring + + align:start position:0% +endergonic they're going to be requiring + + + align:start position:0% +endergonic they're going to be requiring +energy to take place + + align:start position:0% +energy to take place + + + align:start position:0% +energy to take place +I just forgot one thing that I learned + + align:start position:0% +I just forgot one thing that I learned + + + align:start position:0% +I just forgot one thing that I learned +shamefully done + + align:start position:0% +shamefully done + + + align:start position:0% +shamefully done +remember this axis is kilocalories per + + align:start position:0% +remember this axis is kilocalories per + + + align:start position:0% +remember this axis is kilocalories per +mole most commonly when we're talking + + align:start position:0% +mole most commonly when we're talking + + + align:start position:0% +mole most commonly when we're talking +about Delta G or kilo joules per mole if + + align:start position:0% +about Delta G or kilo joules per mole if + + + align:start position:0% +about Delta G or kilo joules per mole if +you're in a different part of the world + + align:start position:0% +you're in a different part of the world + + + align:start position:0% +you're in a different part of the world +but it's important to have units on + + align:start position:0% +but it's important to have units on + + + align:start position:0% +but it's important to have units on +these diagrams so that tells us a little + + align:start position:0% +these diagrams so that tells us a little + + + align:start position:0% +these diagrams so that tells us a little +bit about enzyme catalyzed reactions we + + align:start position:0% +bit about enzyme catalyzed reactions we + + + align:start position:0% +bit about enzyme catalyzed reactions we +need the enzyme to do something about + + align:start position:0% +need the enzyme to do something about + + + align:start position:0% +need the enzyme to do something about +this energy of activation because if we + + align:start position:0% +this energy of activation because if we + + + align:start position:0% +this energy of activation because if we +didn't have a high energy of activation + + align:start position:0% +didn't have a high energy of activation + + + align:start position:0% +didn't have a high energy of activation +I brought a Snickers bar to eat during + + align:start position:0% +I brought a Snickers bar to eat during + + + align:start position:0% +I brought a Snickers bar to eat during +class which is burst into flames right + + align:start position:0% +class which is burst into flames right + + + align:start position:0% +class which is burst into flames right +it has it needs a high energy of + + align:start position:0% +it has it needs a high energy of + + + align:start position:0% +it has it needs a high energy of +activation to keep it stable regularly + + align:start position:0% +activation to keep it stable regularly + + + align:start position:0% +activation to keep it stable regularly +in under regular conditions but only + + align:start position:0% +in under regular conditions but only + + + align:start position:0% +in under regular conditions but only +break down the bonds under time at times + + align:start position:0% +break down the bonds under time at times + + + align:start position:0% +break down the bonds under time at times +when you require that break down right + + align:start position:0% + + + + align:start position:0% + +all right so what are the catalysts do + + align:start position:0% + + + + align:start position:0% + +okay now I've shown you the simple + + align:start position:0% +okay now I've shown you the simple + + + align:start position:0% +okay now I've shown you the simple +reaction the enzyme is a very large + + align:start position:0% +reaction the enzyme is a very large + + + align:start position:0% +reaction the enzyme is a very large +structure it binds to a substrate + + align:start position:0% +structure it binds to a substrate + + + align:start position:0% +structure it binds to a substrate +chemistry happens and it releases a + + align:start position:0% +chemistry happens and it releases a + + + align:start position:0% +chemistry happens and it releases a +product but at the same time you can't + + align:start position:0% +product but at the same time you can't + + + align:start position:0% +product but at the same time you can't +disobey the principles of thermodynamics + + align:start position:0% +disobey the principles of thermodynamics + + + align:start position:0% +disobey the principles of thermodynamics +so there's certain criteria we have to + + align:start position:0% +so there's certain criteria we have to + + + align:start position:0% +so there's certain criteria we have to +think about when we consider an enzyme + + align:start position:0% +think about when we consider an enzyme + + + align:start position:0% +think about when we consider an enzyme +catalyzed reaction so first of all do + + align:start position:0% +catalyzed reaction so first of all do + + + align:start position:0% +catalyzed reaction so first of all do +not disobey whichever law of + + align:start position:0% +not disobey whichever law of + + + align:start position:0% +not disobey whichever law of +thermodynamics is is they do not change + + align:start position:0% + + + + align:start position:0% + +Delta G Delta G is a property of the two + + align:start position:0% +Delta G Delta G is a property of the two + + + align:start position:0% +Delta G Delta G is a property of the two +reactants you're not going to change it + + align:start position:0% +reactants you're not going to change it + + + align:start position:0% +reactants you're not going to change it +with a catalyst it's it's going to have + + align:start position:0% +with a catalyst it's it's going to have + + + align:start position:0% +with a catalyst it's it's going to have +a much more important impact on a + + align:start position:0% +a much more important impact on a + + + align:start position:0% +a much more important impact on a +different parameter which parameter do + + align:start position:0% +different parameter which parameter do + + + align:start position:0% +different parameter which parameter do +enzymes change and help lower over there + + align:start position:0% +enzymes change and help lower over there + + + align:start position:0% +enzymes change and help lower over there +right so catalysts do to change and in + + align:start position:0% +right so catalysts do to change and in + + + align:start position:0% +right so catalysts do to change and in +fact lower energy of activation and + + align:start position:0% +fact lower energy of activation and + + + align:start position:0% +fact lower energy of activation and +we'll talk about how they do that at the + + align:start position:0% +we'll talk about how they do that at the + + + align:start position:0% +we'll talk about how they do that at the +end and then the last rule about a + + align:start position:0% +end and then the last rule about a + + + align:start position:0% +end and then the last rule about a +catalyst is you can recover them + + align:start position:0% + + + + align:start position:0% + +unchanged after a reaction it would be a + + align:start position:0% +unchanged after a reaction it would be a + + + align:start position:0% +unchanged after a reaction it would be a +lousy catalyst if it did it's chemistry + + align:start position:0% +lousy catalyst if it did it's chemistry + + + align:start position:0% +lousy catalyst if it did it's chemistry +and then you've used up the catalysts so + + align:start position:0% +and then you've used up the catalysts so + + + align:start position:0% +and then you've used up the catalysts so +enzyme catalysts are the ultimate green + + align:start position:0% +enzyme catalysts are the ultimate green + + + align:start position:0% +enzyme catalysts are the ultimate green +reagents you can keep using them + + align:start position:0% +reagents you can keep using them + + + align:start position:0% +reagents you can keep using them +thousands and thousands of times to + + align:start position:0% +thousands and thousands of times to + + + align:start position:0% +thousands and thousands of times to +continuously turn over transformations + + align:start position:0% +continuously turn over transformations + + + align:start position:0% +continuously turn over transformations +so you haven't changed a catalyst so the + + align:start position:0% +so you haven't changed a catalyst so the + + + align:start position:0% +so you haven't changed a catalyst so the +things that we want to think about is + + align:start position:0% +things that we want to think about is + + + align:start position:0% +things that we want to think about is +how what are the processes that that + + align:start position:0% +how what are the processes that that + + + align:start position:0% +how what are the processes that that +enzymes can manipulate and I should + + align:start position:0% +enzymes can manipulate and I should + + + align:start position:0% +enzymes can manipulate and I should +probably just quickly run through these + + align:start position:0% +probably just quickly run through these + + + align:start position:0% +probably just quickly run through these +slides so we've talked about these + + align:start position:0% +slides so we've talked about these + + + align:start position:0% +slides so we've talked about these +entities but I put them on the board + + align:start position:0% +entities but I put them on the board + + + align:start position:0% +entities but I put them on the board +because they're particularly important + + align:start position:0% +because they're particularly important + + + align:start position:0% +because they're particularly important +so the energy of activation of a + + align:start position:0% +so the energy of activation of a + + + align:start position:0% +so the energy of activation of a +catalyzed reaction is lower than the + + align:start position:0% +catalyzed reaction is lower than the + + + align:start position:0% +catalyzed reaction is lower than the +uncatalyzed + + align:start position:0% +uncatalyzed + + + align:start position:0% +uncatalyzed +not going to bore you with these + + align:start position:0% +not going to bore you with these + + + align:start position:0% +not going to bore you with these +questions because you can work this out + + align:start position:0% +questions because you can work this out + + + align:start position:0% +questions because you can work this out +quite readily so delta g is the free + + align:start position:0% +quite readily so delta g is the free + + + align:start position:0% +quite readily so delta g is the free +energy that changes and these are + + align:start position:0% +energy that changes and these are + + + align:start position:0% +energy that changes and these are +endergonic because the energy of the + + align:start position:0% +endergonic because the energy of the + + + align:start position:0% +endergonic because the energy of the +products is lower so this is the slide I + + align:start position:0% +products is lower so this is the slide I + + + align:start position:0% +products is lower so this is the slide I +want to get to with respect to the + + align:start position:0% +want to get to with respect to the + + + align:start position:0% +want to get to with respect to the +enzyme to enzyme catalyst so we always + + align:start position:0% +enzyme to enzyme catalyst so we always + + + align:start position:0% +enzyme to enzyme catalyst so we always +think well gosh the enzyme is really + + align:start position:0% +think well gosh the enzyme is really + + + align:start position:0% +think well gosh the enzyme is really +large relative to the size of the + + align:start position:0% +large relative to the size of the + + + align:start position:0% +large relative to the size of the +product that's because all that energy + + align:start position:0% +product that's because all that energy + + + align:start position:0% +product that's because all that energy +within the protein folded structure is + + align:start position:0% +within the protein folded structure is + + + align:start position:0% +within the protein folded structure is +very useful for lowering the energy of + + align:start position:0% +very useful for lowering the energy of + + + align:start position:0% +very useful for lowering the energy of +activation of our transformations so + + align:start position:0% +activation of our transformations so + + + align:start position:0% +activation of our transformations so +let's say I have a reaction that + + align:start position:0% +let's say I have a reaction that + + + align:start position:0% +let's say I have a reaction that +involves two substrates coming together + + align:start position:0% +involves two substrates coming together + + + align:start position:0% +involves two substrates coming together +to make a product right if I'm off the + + align:start position:0% +to make a product right if I'm off the + + + align:start position:0% +to make a product right if I'm off the +enzyme these guys it's gonna take them a + + align:start position:0% +enzyme these guys it's gonna take them a + + + align:start position:0% +enzyme these guys it's gonna take them a +long time to bump into each other to do + + align:start position:0% +long time to bump into each other to do + + + align:start position:0% +long time to bump into each other to do +chemistry the way enzymes catalyze those + + align:start position:0% +chemistry the way enzymes catalyze those + + + align:start position:0% +chemistry the way enzymes catalyze those +types of reactions is they have binding + + align:start position:0% +types of reactions is they have binding + + + align:start position:0% +types of reactions is they have binding +sites for both of those compounds in + + align:start position:0% +sites for both of those compounds in + + + align:start position:0% +sites for both of those compounds in +fact the enzyme acts as a stage 1 + + align:start position:0% +fact the enzyme acts as a stage 1 + + + align:start position:0% +fact the enzyme acts as a stage 1 +substrate binds the other substrate + + align:start position:0% +substrate binds the other substrate + + + align:start position:0% +substrate binds the other substrate +binds their binding close to each other + + align:start position:0% +binds their binding close to each other + + + align:start position:0% +binds their binding close to each other +on the enzyme chemistry can happen it + + align:start position:0% +on the enzyme chemistry can happen it + + + align:start position:0% +on the enzyme chemistry can happen it +favors reactions that involve multiple + + align:start position:0% +favors reactions that involve multiple + + + align:start position:0% +favors reactions that involve multiple +molecules what about another situation + + align:start position:0% +molecules what about another situation + + + align:start position:0% +molecules what about another situation +where you have a bond for example the + + align:start position:0% +where you have a bond for example the + + + align:start position:0% +where you have a bond for example the +amide bond the protease is break it's + + align:start position:0% +amide bond the protease is break it's + + + align:start position:0% +amide bond the protease is break it's +hard to think of how that how can we + + align:start position:0% +hard to think of how that how can we + + + align:start position:0% +hard to think of how that how can we +make that more easy + + align:start position:0% +make that more easy + + + align:start position:0% +make that more easy +well amides are most stable when they + + align:start position:0% +well amides are most stable when they + + + align:start position:0% +well amides are most stable when they +are flat and planar through this + + align:start position:0% +are flat and planar through this + + + align:start position:0% +are flat and planar through this +arrangement of atoms but what can happen + + align:start position:0% +arrangement of atoms but what can happen + + + align:start position:0% +arrangement of atoms but what can happen +on the enzyme is that they can twist + + align:start position:0% +on the enzyme is that they can twist + + + align:start position:0% +on the enzyme is that they can twist +bonds to make them less stable and then + + align:start position:0% +bonds to make them less stable and then + + + align:start position:0% +bonds to make them less stable and then +more easy to hydrolyze + + align:start position:0% +more easy to hydrolyze + + + align:start position:0% +more easy to hydrolyze +so the structure of that enzyme + + align:start position:0% +so the structure of that enzyme + + + align:start position:0% +so the structure of that enzyme +basically holds on to the substrate and + + align:start position:0% +basically holds on to the substrate and + + + align:start position:0% +basically holds on to the substrate and +twists or distorts the bond that you're + + align:start position:0% +twists or distorts the bond that you're + + + align:start position:0% +twists or distorts the bond that you're +trying to do chemistry on to once again + + align:start position:0% +trying to do chemistry on to once again + + + align:start position:0% +trying to do chemistry on to once again +lower the energy of activation another + + align:start position:0% +lower the energy of activation another + + + align:start position:0% +lower the energy of activation another +way enzymes work is in a reaction where + + align:start position:0% +way enzymes work is in a reaction where + + + align:start position:0% +way enzymes work is in a reaction where +you're breaking this bond you might make + + align:start position:0% +you're breaking this bond you might make + + + align:start position:0% +you're breaking this bond you might make +charged intermediates the enzymes there + + align:start position:0% +charged intermediates the enzymes there + + + align:start position:0% +charged intermediates the enzymes there +to hold those charged intermediates in + + align:start position:0% +to hold those charged intermediates in + + + align:start position:0% +to hold those charged intermediates in +order to stabilize them once again to + + align:start position:0% +order to stabilize them once again to + + + align:start position:0% +order to stabilize them once again to +lower energy of activation so it's funny + + align:start position:0% +lower energy of activation so it's funny + + + align:start position:0% +lower energy of activation so it's funny +when you get the question that's well + + align:start position:0% +when you get the question that's well + + + align:start position:0% +when you get the question that's well +how do enzymes catalyze RIA + + align:start position:0% +how do enzymes catalyze RIA + + + align:start position:0% +how do enzymes catalyze RIA +actions there is no one rule you want to + + align:start position:0% +actions there is no one rule you want to + + + align:start position:0% +actions there is no one rule you want to +think about the reactions and then just + + align:start position:0% +think about the reactions and then just + + + align:start position:0% +think about the reactions and then just +think about the ways in which an enzyme + + align:start position:0% +think about the ways in which an enzyme + + + align:start position:0% +think about the ways in which an enzyme +could contribute to that + + align:start position:0% +could contribute to that + + + align:start position:0% +could contribute to that +for example orienting to substrates + + align:start position:0% +for example orienting to substrates + + + align:start position:0% +for example orienting to substrates +ready to do chemistry causing physical + + align:start position:0% +ready to do chemistry causing physical + + + align:start position:0% +ready to do chemistry causing physical +strain in a bond that you want to break + + align:start position:0% +strain in a bond that you want to break + + + align:start position:0% +strain in a bond that you want to break +or comforting electric charges as + + align:start position:0% +or comforting electric charges as + + + align:start position:0% +or comforting electric charges as +charges that form during a reaction + + align:start position:0% +charges that form during a reaction + + + align:start position:0% +charges that form during a reaction +coordinate so their loads and loads of + + align:start position:0% +coordinate so their loads and loads of + + + align:start position:0% +coordinate so their loads and loads of +different principles and it's a really + + align:start position:0% +different principles and it's a really + + + align:start position:0% +different principles and it's a really +important study that's carried that is + + align:start position:0% +important study that's carried that is + + + align:start position:0% +important study that's carried that is +carried out so finally and I think I + + align:start position:0% +carried out so finally and I think I + + + align:start position:0% +carried out so finally and I think I +have a couple you know I have a couple + + align:start position:0% +have a couple you know I have a couple + + + align:start position:0% +have a couple you know I have a couple +of minutes but I want to just describe + + align:start position:0% +of minutes but I want to just describe + + + align:start position:0% +of minutes but I want to just describe +this to you it'll also be covered in the + + align:start position:0% +this to you it'll also be covered in the + + + align:start position:0% +this to you it'll also be covered in the +sections because I'm going to rush it a + + align:start position:0% +sections because I'm going to rush it a + + + align:start position:0% +sections because I'm going to rush it a +bit because this last bit is features a + + align:start position:0% +bit because this last bit is features a + + + align:start position:0% +bit because this last bit is features a +little bit on that on the pset so + + align:start position:0% +little bit on that on the pset so + + + align:start position:0% +little bit on that on the pset so +finally we've enzymes are very commonly + + align:start position:0% +finally we've enzymes are very commonly + + + align:start position:0% +finally we've enzymes are very commonly +the targets of drugs we like to think + + align:start position:0% +the targets of drugs we like to think + + + align:start position:0% +the targets of drugs we like to think +that some drugs are important targets if + + align:start position:0% +that some drugs are important targets if + + + align:start position:0% +that some drugs are important targets if +we deactivate the enzyme we might + + align:start position:0% +we deactivate the enzyme we might + + + align:start position:0% +we deactivate the enzyme we might +mitigate the symptoms of a disease now + + align:start position:0% +mitigate the symptoms of a disease now + + + align:start position:0% +mitigate the symptoms of a disease now +you can't go in and heat the enzyme or + + align:start position:0% +you can't go in and heat the enzyme or + + + align:start position:0% +you can't go in and heat the enzyme or +you know denature the enzyme if you're + + align:start position:0% +you know denature the enzyme if you're + + + align:start position:0% +you know denature the enzyme if you're +trying to treat a person so we do a lot + + align:start position:0% +trying to treat a person so we do a lot + + + align:start position:0% +trying to treat a person so we do a lot +of work to mitigate disease by + + align:start position:0% +of work to mitigate disease by + + + align:start position:0% +of work to mitigate disease by +inhibiting enzymes with small molecules + + align:start position:0% +inhibiting enzymes with small molecules + + + align:start position:0% +inhibiting enzymes with small molecules +so in these slides I described to you + + align:start position:0% +so in these slides I described to you + + + align:start position:0% +so in these slides I described to you +the types of molecules that may alter + + align:start position:0% +the types of molecules that may alter + + + align:start position:0% +the types of molecules that may alter +the chemistry of a transformation so if + + align:start position:0% +the chemistry of a transformation so if + + + align:start position:0% +the chemistry of a transformation so if +a substrate binds to an enzyme active + + align:start position:0% +a substrate binds to an enzyme active + + + align:start position:0% +a substrate binds to an enzyme active +site we often do this pac-man rendition + + align:start position:0% +site we often do this pac-man rendition + + + align:start position:0% +site we often do this pac-man rendition +you could design a molecule that binds + + align:start position:0% +you could design a molecule that binds + + + align:start position:0% +you could design a molecule that binds +there instead and basically inhibits the + + align:start position:0% +there instead and basically inhibits the + + + align:start position:0% +there instead and basically inhibits the +substrate from getting there this would + + align:start position:0% +substrate from getting there this would + + + align:start position:0% +substrate from getting there this would +be called a simple reversible inhibitor + + align:start position:0% +be called a simple reversible inhibitor + + + align:start position:0% +be called a simple reversible inhibitor +that's competitive with the active site + + align:start position:0% +that's competitive with the active site + + + align:start position:0% +that's competitive with the active site +there are other inhibitors that will + + align:start position:0% +there are other inhibitors that will + + + align:start position:0% +there are other inhibitors that will +bind to the enzyme but do chemistry with + + align:start position:0% +bind to the enzyme but do chemistry with + + + align:start position:0% +bind to the enzyme but do chemistry with +it and stay blocked at the enzyme and + + align:start position:0% +it and stay blocked at the enzyme and + + + align:start position:0% +it and stay blocked at the enzyme and +that would be called an irreversible + + align:start position:0% +that would be called an irreversible + + + align:start position:0% +that would be called an irreversible +competitive inhibitor you can't get the + + align:start position:0% +competitive inhibitor you can't get the + + + align:start position:0% +competitive inhibitor you can't get the +inhibitor off and there's differences in + + align:start position:0% +inhibitor off and there's differences in + + + align:start position:0% +inhibitor off and there's differences in +the way you can reverse this because for + + align:start position:0% +the way you can reverse this because for + + + align:start position:0% +the way you can reverse this because for +example up here if I add a lot more + + align:start position:0% +example up here if I add a lot more + + + align:start position:0% +example up here if I add a lot more +substrate and these are equilibria I can + + align:start position:0% +substrate and these are equilibria I can + + + align:start position:0% +substrate and these are equilibria I can +get my reaction to happen anyway but + + align:start position:0% +get my reaction to happen anyway but + + + align:start position:0% +get my reaction to happen anyway but +here I could add as much substrate as + + align:start position:0% +here I could add as much substrate as + + + align:start position:0% +here I could add as much substrate as +possible but it won't help it won't + + align:start position:0% +possible but it won't help it won't + + + align:start position:0% +possible but it won't help it won't +reverse the transformer + + align:start position:0% +reverse the transformer + + + align:start position:0% +reverse the transformer +okay and there's a question here to + + align:start position:0% +okay and there's a question here to + + + align:start position:0% +okay and there's a question here to +restore the reaction the answer really + + align:start position:0% +restore the reaction the answer really + + + align:start position:0% +restore the reaction the answer really +is you just have to start with new + + align:start position:0% +is you just have to start with new + + + align:start position:0% +is you just have to start with new +enzyme because you've covalently changed + + align:start position:0% +enzyme because you've covalently changed + + + align:start position:0% +enzyme because you've covalently changed +the protein structure the last type of + + align:start position:0% +the protein structure the last type of + + + align:start position:0% +the protein structure the last type of +inhibitors that are important the ones + + align:start position:0% +inhibitors that are important the ones + + + align:start position:0% +inhibitors that are important the ones +that bind at different sites on the + + align:start position:0% +that bind at different sites on the + + + align:start position:0% +that bind at different sites on the +enzymes and they are called allosteric + + align:start position:0% +enzymes and they are called allosteric + + + align:start position:0% +enzymes and they are called allosteric +allo always means different so if you + + align:start position:0% +allo always means different so if you + + + align:start position:0% +allo always means different so if you +have a compound that's an allosteric + + align:start position:0% +have a compound that's an allosteric + + + align:start position:0% +have a compound that's an allosteric +inhibitor it might bind on another face + + align:start position:0% +inhibitor it might bind on another face + + + align:start position:0% +inhibitor it might bind on another face +of the enzyme but it'll alter the active + + align:start position:0% +of the enzyme but it'll alter the active + + + align:start position:0% +of the enzyme but it'll alter the active +sites so it doesn't work that's an + + align:start position:0% +sites so it doesn't work that's an + + + align:start position:0% +sites so it doesn't work that's an +allosteric inhibitor and the final type + + align:start position:0% +allosteric inhibitor and the final type + + + align:start position:0% +allosteric inhibitor and the final type +of compound is an allosteric activator + + align:start position:0% +of compound is an allosteric activator + + + align:start position:0% +of compound is an allosteric activator +that may bind somewhere else on the + + align:start position:0% +that may bind somewhere else on the + + + align:start position:0% +that may bind somewhere else on the +enzyme but make it more active so these + + align:start position:0% +enzyme but make it more active so these + + + align:start position:0% +enzyme but make it more active so these +are the way small molecules work I'd + + align:start position:0% +are the way small molecules work I'd + + + align:start position:0% +are the way small molecules work I'd +like to encourage the TAS to just cover + + align:start position:0% +like to encourage the TAS to just cover + + + align:start position:0% +like to encourage the TAS to just cover +this in a little bit more detail because + + align:start position:0% +this in a little bit more detail because + + + align:start position:0% +this in a little bit more detail because +I brushed it and I'll also remain it at + + align:start position:0% +I brushed it and I'll also remain it at + + + align:start position:0% +I brushed it and I'll also remain it at +the beginning of the next class but bear + + align:start position:0% +the beginning of the next class but bear + + + align:start position:0% +the beginning of the next class but bear +in mind we should have everything + + align:start position:0% +in mind we should have everything + + + align:start position:0% +in mind we should have everything +covered now for the problem set one and + + align:start position:0% +covered now for the problem set one and + + + align:start position:0% +covered now for the problem set one and +if you have any questions reach out to + + align:start position:0% +if you have any questions reach out to + + + align:start position:0% +if you have any questions reach out to +us cover them in section and I'll + + align:start position:0% +us cover them in section and I'll + + + align:start position:0% +us cover them in section and I'll +reiterate a little bit of this in the + + align:start position:0% +reiterate a little bit of this in the + + + align:start position:0% +reiterate a little bit of this in the +next class and finally there's a little + + align:start position:0% +next class and finally there's a little + + + align:start position:0% +next class and finally there's a little +bit of reading if you would like to + + align:start position:0% +bit of reading if you would like to + + + align:start position:0% +bit of reading if you would like to +prepare we'll talk about carbohydrates + + align:start position:0% +prepare we'll talk about carbohydrates + + + align:start position:0% +prepare we'll talk about carbohydrates +next time one of my favorite molecules + + align:start position:0% +next time one of my favorite molecules + + + align:start position:0% +next time one of my favorite molecules +and there's also a fabulous set of + + align:start position:0% +and there's also a fabulous set of + + + align:start position:0% +and there's also a fabulous set of +videos on how enzymes work and the + + align:start position:0% +videos on how enzymes work and the + + + align:start position:0% +videos on how enzymes work and the +protein databank a site and you will see + + align:start position:0% +protein databank a site and you will see + + + align:start position:0% +protein databank a site and you will see +this little handout on the slides + + align:start position:0% +this little handout on the slides + + + align:start position:0% +this little handout on the slides +version of the slides that's posted + + align:start position:0% + + + + align:start position:0% + +you \ No newline at end of file diff --git a/QVDLMx0Guiw.txt b/QVDLMx0Guiw.txt new file mode 100644 index 0000000000000000000000000000000000000000..4d50d139b24f4cfc965f3736fe39feec5ead7e29 --- /dev/null +++ b/QVDLMx0Guiw.txt @@ -0,0 +1,11288 @@ +align:start position:0% + +Yeah. So, we're sort of in the last part + + align:start position:0% +Yeah. So, we're sort of in the last part + + + align:start position:0% +Yeah. So, we're sort of in the last part +of the class now and I've been + + align:start position:0% +of the class now and I've been + + + align:start position:0% +of the class now and I've been +reflecting on what what to do together. + + align:start position:0% +reflecting on what what to do together. + + + align:start position:0% +reflecting on what what to do together. +Um and uh I asked everybody for for some + + align:start position:0% +Um and uh I asked everybody for for some + + + align:start position:0% +Um and uh I asked everybody for for some +input, a little survey about what topics + + align:start position:0% +input, a little survey about what topics + + + align:start position:0% +input, a little survey about what topics +to do and how much detail to do. + + align:start position:0% +to do and how much detail to do. + + + align:start position:0% +to do and how much detail to do. +Um there was no consensus in the survey + + align:start position:0% +Um there was no consensus in the survey + + + align:start position:0% +Um there was no consensus in the survey +of of what people wanted to do. Um + + align:start position:0% +of of what people wanted to do. Um + + + align:start position:0% +of of what people wanted to do. Um +but I've decided I would like to do for + + align:start position:0% +but I've decided I would like to do for + + + align:start position:0% +but I've decided I would like to do for +a couple of weeks uh talk about some + + align:start position:0% +a couple of weeks uh talk about some + + + align:start position:0% +a couple of weeks uh talk about some +applications of projection theory in + + align:start position:0% +applications of projection theory in + + + align:start position:0% +applications of projection theory in +other areas. Um and then in the last + + align:start position:0% +other areas. Um and then in the last + + + align:start position:0% +other areas. Um and then in the last +couple weeks try to talk about at least + + align:start position:0% +couple weeks try to talk about at least + + + align:start position:0% +couple weeks try to talk about at least +the some of the main ideas in the proof + + align:start position:0% +the some of the main ideas in the proof + + + align:start position:0% +the some of the main ideas in the proof +of the sharp projection theorem. + + align:start position:0% +of the sharp projection theorem. + + + align:start position:0% +of the sharp projection theorem. +Um + + align:start position:0% +Um + + + align:start position:0% +Um +yeah so we recently had been doing uh + + align:start position:0% +yeah so we recently had been doing uh + + + align:start position:0% +yeah so we recently had been doing uh +Burgans's projection theorem and the + + align:start position:0% +Burgans's projection theorem and the + + + align:start position:0% +Burgans's projection theorem and the +burganc cat's projection theorem in + + align:start position:0% +burganc cat's projection theorem in + + + align:start position:0% +burganc cat's projection theorem in +finite fields and um we so + + align:start position:0% +finite fields and um we so + + + align:start position:0% +finite fields and um we so +feeling that that we really had to work + + align:start position:0% +feeling that that we really had to work + + + align:start position:0% +feeling that that we really had to work +pretty hard for those things and it was + + align:start position:0% +pretty hard for those things and it was + + + align:start position:0% +pretty hard for those things and it was +striking that we had to work pretty hard + + align:start position:0% +striking that we had to work pretty hard + + + align:start position:0% +striking that we had to work pretty hard +just to get this like very small uh + + align:start position:0% +just to get this like very small uh + + + align:start position:0% +just to get this like very small uh +improvement um and um so in some of what + + align:start position:0% +improvement um and um so in some of what + + + align:start position:0% +improvement um and um so in some of what +we'll do in the rest of the class I I + + align:start position:0% +we'll do in the rest of the class I I + + + align:start position:0% +we'll do in the rest of the class I I +will try to show that that that small + + align:start position:0% +will try to show that that that small + + + align:start position:0% +will try to show that that that small +improvement is really valuable + + align:start position:0% +improvement is really valuable + + + align:start position:0% +improvement is really valuable +Um + + align:start position:0% +Um + + + align:start position:0% +Um +okay. Um so the yeah so the so so the + + align:start position:0% +okay. Um so the yeah so the so so the + + + align:start position:0% +okay. Um so the yeah so the so so the +the plan for the rest of the class is + + align:start position:0% +the plan for the rest of the class is + + + align:start position:0% +the plan for the rest of the class is +for for about one week we'll talk about + + align:start position:0% +for for about one week we'll talk about + + + align:start position:0% +for for about one week we'll talk about +random walks on groups and then for + + align:start position:0% +random walks on groups and then for + + + align:start position:0% +random walks on groups and then for +about one week we'll talk about + + align:start position:0% +about one week we'll talk about + + + align:start position:0% +about one week we'll talk about +homogeneous dynamics. Um and then at the + + align:start position:0% +homogeneous dynamics. Um and then at the + + + align:start position:0% +homogeneous dynamics. Um and then at the +end we'll talk about the sharp + + align:start position:0% +end we'll talk about the sharp + + + align:start position:0% +end we'll talk about the sharp +projection theorem. + + align:start position:0% +projection theorem. + + + align:start position:0% +projection theorem. +Okay. Um + + align:start position:0% +Okay. Um + + + align:start position:0% +Okay. Um +um cool. And also in the last few + + align:start position:0% +um cool. And also in the last few + + + align:start position:0% +um cool. And also in the last few +classes I felt that we were um doing + + align:start position:0% +classes I felt that we were um doing + + + align:start position:0% +classes I felt that we were um doing +some very technical things and and and + + align:start position:0% +some very technical things and and and + + + align:start position:0% +some very technical things and and and +uh um sometimes a little bit of a + + align:start position:0% +uh um sometimes a little bit of a + + + align:start position:0% +uh um sometimes a little bit of a +struggle. Um so for for today what I + + align:start position:0% +struggle. Um so for for today what I + + + align:start position:0% +struggle. Um so for for today what I +want to do is to give I hope a very + + align:start position:0% +want to do is to give I hope a very + + + align:start position:0% +want to do is to give I hope a very +friendly induct in introduction to + + align:start position:0% +friendly induct in introduction to + + + align:start position:0% +friendly induct in introduction to +random walks on groups and then um next + + align:start position:0% +random walks on groups and then um next + + + align:start position:0% +random walks on groups and then um next +week on Tuesday to explain how + + align:start position:0% +week on Tuesday to explain how + + + align:start position:0% +week on Tuesday to explain how +projection theory helps to figure out + + align:start position:0% +projection theory helps to figure out + + + align:start position:0% +projection theory helps to figure out +some interesting things. + + align:start position:0% +some interesting things. + + + align:start position:0% +some interesting things. +Okay. + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +So talk about + + align:start position:0% + + + + align:start position:0% + +random walks + + align:start position:0% +random walks + + + align:start position:0% +random walks +of groups. + + align:start position:0% + + + + align:start position:0% + +All right. So suppose that G is a finite + + align:start position:0% +All right. So suppose that G is a finite + + + align:start position:0% +All right. So suppose that G is a finite +group + + align:start position:0% +group + + + align:start position:0% +group +and then mu is a probability measure on + + align:start position:0% +and then mu is a probability measure on + + + align:start position:0% +and then mu is a probability measure on +G. So I'll think of it + + align:start position:0% +G. So I'll think of it + + + align:start position:0% +G. So I'll think of it +as a function on G + + align:start position:0% +as a function on G + + + align:start position:0% +as a function on G +which is non- negative and sums to one. + + align:start position:0% + + + + align:start position:0% + +Okay. So if you have a probability + + align:start position:0% +Okay. So if you have a probability + + + align:start position:0% +Okay. So if you have a probability +measure like this, you can do a random + + align:start position:0% +measure like this, you can do a random + + + align:start position:0% +measure like this, you can do a random +walk where at each step of the random + + align:start position:0% +walk where at each step of the random + + + align:start position:0% +walk where at each step of the random +walk, you pick an element of G by this + + align:start position:0% +walk, you pick an element of G by this + + + align:start position:0% +walk, you pick an element of G by this +probability and then you move by that + + align:start position:0% +probability and then you move by that + + + align:start position:0% +probability and then you move by that +element. So here's how the random walk + + align:start position:0% +element. So here's how the random walk + + + align:start position:0% +element. So here's how the random walk +works. + + align:start position:0% + + + + align:start position:0% + +So you start somewhere + + align:start position:0% +So you start somewhere + + + align:start position:0% +So you start somewhere +say at G0 then you sample + + align:start position:0% +say at G0 then you sample + + + align:start position:0% +say at G0 then you sample +a step h from mu + + align:start position:0% +a step h from mu + + + align:start position:0% +a step h from mu +and the next guy g1 is g 0 * h. + + align:start position:0% +and the next guy g1 is g 0 * h. + + + align:start position:0% +and the next guy g1 is g 0 * h. +So that's one step of the random walk + + align:start position:0% +So that's one step of the random walk + + + align:start position:0% +So that's one step of the random walk +and then you can keep doing this. + + align:start position:0% + + + + align:start position:0% + +Okay. And um so if you do take K steps + + align:start position:0% +Okay. And um so if you do take K steps + + + align:start position:0% +Okay. And um so if you do take K steps +of the random walk then that will be + + align:start position:0% +of the random walk then that will be + + + align:start position:0% +of the random walk then that will be +there will be some probability + + align:start position:0% +there will be some probability + + + align:start position:0% +there will be some probability +distribution of where you end up after k + + align:start position:0% +distribution of where you end up after k + + + align:start position:0% +distribution of where you end up after k +steps and the main question about one + + align:start position:0% +steps and the main question about one + + + align:start position:0% +steps and the main question about one +main question about random walks is how + + align:start position:0% +main question about random walks is how + + + align:start position:0% +main question about random walks is how +evenly distributed is that probability + + align:start position:0% +evenly distributed is that probability + + + align:start position:0% +evenly distributed is that probability +distribution. + + align:start position:0% +distribution. + + + align:start position:0% +distribution. +Um so + + align:start position:0% +Um so + + + align:start position:0% +Um so +question + + align:start position:0% +question + + + align:start position:0% +question +how evenly + + align:start position:0% +how evenly + + + align:start position:0% +how evenly +distributed + + align:start position:0% + + + + align:start position:0% + +is uh the random walk after k steps. + + align:start position:0% + + + + align:start position:0% + +Okay. And we'll make we'll make this + + align:start position:0% +Okay. And we'll make we'll make this + + + align:start position:0% +Okay. And we'll make we'll make this +more precise in a moment. + + align:start position:0% + + + + align:start position:0% + +All right. So, + + align:start position:0% +All right. So, + + + align:start position:0% +All right. So, +so we um it is helpful to describe this + + align:start position:0% +so we um it is helpful to describe this + + + align:start position:0% +so we um it is helpful to describe this +random walk using uh convolution. + + align:start position:0% + + + + align:start position:0% + +Okay, so convolution on a group looks + + align:start position:0% +Okay, so convolution on a group looks + + + align:start position:0% +Okay, so convolution on a group looks +like this. We have two functions f_sub_1 + + align:start position:0% +like this. We have two functions f_sub_1 + + + align:start position:0% +like this. We have two functions f_sub_1 +and f_sub_2 on this group. And then if I + + align:start position:0% +and f_sub_2 on this group. And then if I + + + align:start position:0% +and f_sub_2 on this group. And then if I +convolve them with each other + + align:start position:0% +convolve them with each other + + + align:start position:0% +convolve them with each other +and I evaluate that at g, that's the sum + + align:start position:0% +and I evaluate that at g, that's the sum + + + align:start position:0% +and I evaluate that at g, that's the sum +g1 * g2 = g. f of g1 f_sub_1 of g1 + + align:start position:0% +g1 * g2 = g. f of g1 f_sub_1 of g1 + + + align:start position:0% +g1 * g2 = g. f of g1 f_sub_1 of g1 +f_sub_2 of g2. + + align:start position:0% +f_sub_2 of g2. + + + align:start position:0% +f_sub_2 of g2. +That's the sum over all the g1 and g2 + + align:start position:0% +That's the sum over all the g1 and g2 + + + align:start position:0% +That's the sum over all the g1 and g2 +that multiply to g of of this. + + align:start position:0% + + + + align:start position:0% + +Okay. Um and then for mu we can make an + + align:start position:0% +Okay. Um and then for mu we can make an + + + align:start position:0% +Okay. Um and then for mu we can make an +operator and t mu of f is just f + + align:start position:0% +operator and t mu of f is just f + + + align:start position:0% +operator and t mu of f is just f +convolved with mu. And this operator + + align:start position:0% +convolved with mu. And this operator + + + align:start position:0% +convolved with mu. And this operator +basically describes this random walk. + + align:start position:0% +basically describes this random walk. + + + align:start position:0% +basically describes this random walk. +So let's say how they're related. So + + align:start position:0% +So let's say how they're related. So + + + align:start position:0% +So let's say how they're related. So +suppose I were to take t mu and apply it + + align:start position:0% +suppose I were to take t mu and apply it + + + align:start position:0% +suppose I were to take t mu and apply it +to the delta function at g knot and + + align:start position:0% +to the delta function at g knot and + + + align:start position:0% +to the delta function at g knot and +evaluate that at some g. + + align:start position:0% +evaluate that at some g. + + + align:start position:0% +evaluate that at some g. +Um + + align:start position:0% +Um + + + align:start position:0% +Um +okay. So let's let's see what's a good + + align:start position:0% +okay. So let's let's see what's a good + + + align:start position:0% +okay. So let's let's see what's a good +way to write this. + + align:start position:0% +way to write this. + + + align:start position:0% +way to write this. +Um so that's the sum. Um actually let me + + align:start position:0% +Um so that's the sum. Um actually let me + + + align:start position:0% +Um so that's the sum. Um actually let me +look at how I wrote it in my notes. I + + align:start position:0% +look at how I wrote it in my notes. I + + + align:start position:0% +look at how I wrote it in my notes. I +tried writing this a few ways and then I + + align:start position:0% +tried writing this a few ways and then I + + + align:start position:0% +tried writing this a few ways and then I +decided there was a good way to write + + align:start position:0% +decided there was a good way to write + + + align:start position:0% +decided there was a good way to write +it. + + align:start position:0% +it. + + + align:start position:0% +it. +Right? Yeah. Let's write it this way. + + align:start position:0% +Right? Yeah. Let's write it this way. + + + align:start position:0% +Right? Yeah. Let's write it this way. +So suppose I want to evaluate this at g* + + align:start position:0% +So suppose I want to evaluate this at g* + + + align:start position:0% +So suppose I want to evaluate this at g* +h. So that's the sum over g1 * g2 = g * + + align:start position:0% +h. So that's the sum over g1 * g2 = g * + + + align:start position:0% +h. So that's the sum over g1 * g2 = g * +h of delta function at g of g1 time mu + + align:start position:0% +h of delta function at g of g1 time mu + + + align:start position:0% +h of delta function at g of g1 time mu +of g2. + + align:start position:0% +of g2. + + + align:start position:0% +of g2. +All right. So the only way that this sum + + align:start position:0% +All right. So the only way that this sum + + + align:start position:0% +All right. So the only way that this sum +can be not zero is if g1 is g0. + + align:start position:0% + + + + align:start position:0% + +So there's only one term in this sum. + + align:start position:0% +So there's only one term in this sum. + + + align:start position:0% +So there's only one term in this sum. +So this um g 0 * g2 is g 0 * h of mu of + + align:start position:0% +So this um g 0 * g2 is g 0 * h of mu of + + + align:start position:0% +So this um g 0 * g2 is g 0 * h of mu of +g2. + + align:start position:0% +g2. + + + align:start position:0% +g2. +There's only one term and it's the term + + align:start position:0% +There's only one term and it's the term + + + align:start position:0% +There's only one term and it's the term +where g2 is h. + + align:start position:0% + + + + align:start position:0% + +Okay. So this thing is the probability + + align:start position:0% +Okay. So this thing is the probability + + + align:start position:0% +Okay. So this thing is the probability +distribution of one step of the random + + align:start position:0% +distribution of one step of the random + + + align:start position:0% +distribution of one step of the random +walk. The probability if I started at g + + align:start position:0% +walk. The probability if I started at g + + + align:start position:0% +walk. The probability if I started at g +that I end up at g* h is mu of h. That's + + align:start position:0% +that I end up at g* h is mu of h. That's + + + align:start position:0% +that I end up at g* h is mu of h. That's +the definition of my random walk. So + + align:start position:0% +the definition of my random walk. So + + + align:start position:0% +the definition of my random walk. So +this operator is performing one step of + + align:start position:0% +this operator is performing one step of + + + align:start position:0% +this operator is performing one step of +the random walker. And therefore if I + + align:start position:0% +the random walker. And therefore if I + + + align:start position:0% +the random walker. And therefore if I +take t mu to the k of delta g0 that's uh + + align:start position:0% +take t mu to the k of delta g0 that's uh + + + align:start position:0% +take t mu to the k of delta g0 that's uh +like k steps of the random walk + + align:start position:0% +like k steps of the random walk + + + align:start position:0% +like k steps of the random walk +starting at g. + + align:start position:0% + + + + align:start position:0% + +Okay. + + align:start position:0% + + + + align:start position:0% + +Um actually let me say this I could say + + align:start position:0% +Um actually let me say this I could say + + + align:start position:0% +Um actually let me say this I could say +this better. + + align:start position:0% + + + + align:start position:0% + +So this is the probability + + align:start position:0% +So this is the probability + + + align:start position:0% +So this is the probability +that a random walk is at g + + align:start position:0% +that a random walk is at g + + + align:start position:0% +that a random walk is at g +after k steps. + + align:start position:0% + + + + align:start position:0% + +Okay. So now we can take this question + + align:start position:0% +Okay. So now we can take this question + + + align:start position:0% +Okay. So now we can take this question +how evenly distributed is the random + + align:start position:0% +how evenly distributed is the random + + + align:start position:0% +how evenly distributed is the random +walk. We can write that as a precise + + align:start position:0% +walk. We can write that as a precise + + + align:start position:0% +walk. We can write that as a precise +question about this. I'll call it + + align:start position:0% +question about this. I'll call it + + + align:start position:0% +question about this. I'll call it +question one. + + align:start position:0% + + + + align:start position:0% + +So I'd like to estimate + + align:start position:0% + + + + align:start position:0% + +okay t mu to the k of delta g0. So this + + align:start position:0% +okay t mu to the k of delta g0. So this + + + align:start position:0% +okay t mu to the k of delta g0. So this +is the actual probability distribution. + + align:start position:0% +is the actual probability distribution. + + + align:start position:0% +is the actual probability distribution. +And if the probability was completely + + align:start position:0% +And if the probability was completely + + + align:start position:0% +And if the probability was completely +even over the whole group, it would be + + align:start position:0% +even over the whole group, it would be + + + align:start position:0% +even over the whole group, it would be +one over the size of the group + + align:start position:0% +one over the size of the group + + + align:start position:0% +one over the size of the group +everywhere. So I'm going to see how + + align:start position:0% +everywhere. So I'm going to see how + + + align:start position:0% +everywhere. So I'm going to see how +close it is to that by measuring the + + align:start position:0% +close it is to that by measuring the + + + align:start position:0% +close it is to that by measuring the +norm of this difference. So I like to + + align:start position:0% +norm of this difference. So I like to + + + align:start position:0% +norm of this difference. So I like to +estimate that. Okay. And L2 is helpful + + align:start position:0% +estimate that. Okay. And L2 is helpful + + + align:start position:0% +estimate that. Okay. And L2 is helpful +but also perhaps a little arbitrary. You + + align:start position:0% +but also perhaps a little arbitrary. You + + + align:start position:0% +but also perhaps a little arbitrary. You +could also put other norms. So could put + + align:start position:0% +could also put other norms. So could put + + + align:start position:0% +could also put other norms. So could put +or L infinity or maybe some other norm. + + align:start position:0% + + + + align:start position:0% + +Okay. So this is the kind of question + + align:start position:0% +Okay. So this is the kind of question + + + align:start position:0% +Okay. So this is the kind of question +about random walks on groups that we are + + align:start position:0% +about random walks on groups that we are + + + align:start position:0% +about random walks on groups that we are +going to try to understand. + + align:start position:0% +going to try to understand. + + + align:start position:0% +going to try to understand. +All right. So um to understand this it + + align:start position:0% +All right. So um to understand this it + + + align:start position:0% +All right. So um to understand this it +is helpful to notice that this is a + + align:start position:0% +is helpful to notice that this is a + + + align:start position:0% +is helpful to notice that this is a +linear operator. This t- mu is a linear + + align:start position:0% +linear operator. This t- mu is a linear + + + align:start position:0% +linear operator. This t- mu is a linear +operator. It's basically a matrix. And + + align:start position:0% +operator. It's basically a matrix. And + + + align:start position:0% +operator. It's basically a matrix. And +it's helpful to think about that um in + + align:start position:0% +it's helpful to think about that um in + + + align:start position:0% +it's helpful to think about that um in +terms of matrix ideas like the singular + + align:start position:0% +terms of matrix ideas like the singular + + + align:start position:0% +terms of matrix ideas like the singular +values and singular vectors of this + + align:start position:0% +values and singular vectors of this + + + align:start position:0% +values and singular vectors of this +matrix. + + align:start position:0% + + + + align:start position:0% + +So t mu plus a linear operator + + align:start position:0% + + + + align:start position:0% + +and we're going to study + + align:start position:0% +and we're going to study + + + align:start position:0% +and we're going to study +singular values and singular vectors + + align:start position:0% + + + + align:start position:0% + +of t. + + align:start position:0% +of t. + + + align:start position:0% +of t. +Okay. So there is um + + align:start position:0% +Okay. So there is um + + + align:start position:0% +Okay. So there is um +one um simple singular value which is or + + align:start position:0% +one um simple singular value which is or + + + align:start position:0% +one um simple singular value which is or +value I guess that t mu of one is one. + + align:start position:0% +value I guess that t mu of one is one. + + + align:start position:0% +value I guess that t mu of one is one. +>> Yeah. + + align:start position:0% +>> Yeah. + + + align:start position:0% +>> Yeah. +>> Are singular values and singular vectors + + align:start position:0% +>> Are singular values and singular vectors + + + align:start position:0% +>> Are singular values and singular vectors +just the same as values and values. + + align:start position:0% +just the same as values and values. + + + align:start position:0% +just the same as values and values. +>> Um they are closely related. Um + + align:start position:0% +>> Um they are closely related. Um + + + align:start position:0% +>> Um they are closely related. Um +so let me do a quick review of singular + + align:start position:0% +so let me do a quick review of singular + + + align:start position:0% +so let me do a quick review of singular +values and values. Right. + + align:start position:0% + + + + align:start position:0% + +Um, + + align:start position:0% +Um, + + + align:start position:0% +Um, +so if you have a a matrix and you think + + align:start position:0% +so if you have a a matrix and you think + + + align:start position:0% +so if you have a a matrix and you think +about what it does to the unit ball, it + + align:start position:0% +about what it does to the unit ball, it + + + align:start position:0% +about what it does to the unit ball, it +will turn the unit ball into an + + align:start position:0% +will turn the unit ball into an + + + align:start position:0% +will turn the unit ball into an +ellipsoid. + + align:start position:0% +ellipsoid. + + + align:start position:0% +ellipsoid. +Um and the principal axes of this + + align:start position:0% +Um and the principal axes of this + + + align:start position:0% +Um and the principal axes of this +ellipsoid are the singular values sigma + + align:start position:0% +ellipsoid are the singular values sigma + + + align:start position:0% +ellipsoid are the singular values sigma + + align:start position:0% + + + align:start position:0% +sigma 2. + + align:start position:0% + + + + align:start position:0% + +Okay. And then um + + align:start position:0% + + + + align:start position:0% + +uh so if we look at the pre-im images of + + align:start position:0% +uh so if we look at the pre-im images of + + + align:start position:0% +uh so if we look at the pre-im images of +these things those will be the singular + + align:start position:0% +these things those will be the singular + + + align:start position:0% +these things those will be the singular +vectors. + + align:start position:0% +vectors. + + + align:start position:0% +vectors. +So well depending on the matrix they + + align:start position:0% +So well depending on the matrix they + + + align:start position:0% +So well depending on the matrix they +could be pointing any which way but + + align:start position:0% +could be pointing any which way but + + + align:start position:0% +could be pointing any which way but +maybe that's um v2 + + align:start position:0% +maybe that's um v2 + + + align:start position:0% +maybe that's um v2 +and that is v1. + + align:start position:0% +and that is v1. + + + align:start position:0% +and that is v1. +Okay. And they will always be so we'll + + align:start position:0% +Okay. And they will always be so we'll + + + align:start position:0% +Okay. And they will always be so we'll +have um + + align:start position:0% + + + + align:start position:0% + +uh + + align:start position:0% + + + + align:start position:0% + +so the the vi or orthonormal + + align:start position:0% +so the the vi or orthonormal + + + align:start position:0% +so the the vi or orthonormal +and the size of mvi + + align:start position:0% +and the size of mvi + + + align:start position:0% +and the size of mvi +is sigma. + + align:start position:0% +is sigma. + + + align:start position:0% +is sigma. +Um + + align:start position:0% +Um + + + align:start position:0% +Um +and the mvi are also worth are also + + align:start position:0% +and the mvi are also worth are also + + + align:start position:0% +and the mvi are also worth are also +orthogonal. Those + + align:start position:0% + + + + align:start position:0% + +are the singular vectors. + + align:start position:0% + + + + align:start position:0% + +Okay. Now they are not generally igen + + align:start position:0% +Okay. Now they are not generally igen + + + align:start position:0% +Okay. Now they are not generally igen +vectors in the sense that mvi will not + + align:start position:0% +vectors in the sense that mvi will not + + + align:start position:0% +vectors in the sense that mvi will not +usually be a multiple of vi. Uh but they + + align:start position:0% +usually be a multiple of vi. Uh but they + + + align:start position:0% +usually be a multiple of vi. Uh but they +are closely related to them. Um the vi + + align:start position:0% +are closely related to them. Um the vi + + + align:start position:0% +are closely related to them. Um the vi +are the igen vectors + + align:start position:0% + + + + align:start position:0% + +of m star or m m star I guess. Um + + align:start position:0% +of m star or m m star I guess. Um + + + align:start position:0% +of m star or m m star I guess. Um +and the uh sigma i squared are the igen + + align:start position:0% +and the uh sigma i squared are the igen + + + align:start position:0% +and the uh sigma i squared are the igen +values of m star mic + + align:start position:0% +values of m star mic + + + align:start position:0% +values of m star mic +mm star. + + align:start position:0% + + + + align:start position:0% + +Um + + align:start position:0% +Um + + + align:start position:0% +Um +so in particular this biggest uh this + + align:start position:0% +so in particular this biggest uh this + + + align:start position:0% +so in particular this biggest uh this +biggest singular vector measures the + + align:start position:0% +biggest singular vector measures the + + + align:start position:0% +biggest singular vector measures the +operator norm of the matrix which is + + align:start position:0% +operator norm of the matrix which is + + + align:start position:0% +operator norm of the matrix which is +that the the um so these are these are + + align:start position:0% +that the the um so these are these are + + + align:start position:0% +that the the um so these are these are +ordered like this and um + + align:start position:0% +ordered like this and um + + + align:start position:0% +ordered like this and um +MV + + align:start position:0% + + + + align:start position:0% + +is at most sigma 1 + + align:start position:0% + + + + align:start position:0% + +Okay, so the reason we're talking about + + align:start position:0% +Okay, so the reason we're talking about + + + align:start position:0% +Okay, so the reason we're talking about +singular values is we're going to care + + align:start position:0% +singular values is we're going to care + + + align:start position:0% +singular values is we're going to care +about stuff like this. And + + align:start position:0% +about stuff like this. And + + + align:start position:0% +about stuff like this. And +this is naturally associated with + + align:start position:0% +this is naturally associated with + + + align:start position:0% +this is naturally associated with +singular values. If m is not symmetric, + + align:start position:0% +singular values. If m is not symmetric, + + + align:start position:0% +singular values. If m is not symmetric, +it's not necessarily the same as talking + + align:start position:0% +it's not necessarily the same as talking + + + align:start position:0% +it's not necessarily the same as talking +about values. + + align:start position:0% + + + + align:start position:0% + +Okay. + + align:start position:0% +Okay. + + + align:start position:0% +Okay. +Um, + + align:start position:0% + + + + align:start position:0% + +okay. So, if we take this tu of the + + align:start position:0% +okay. So, if we take this tu of the + + + align:start position:0% +okay. So, if we take this tu of the +function one, the constant function, + + align:start position:0% +function one, the constant function, + + + align:start position:0% +function one, the constant function, +we'll just get one because this t- mu is + + align:start position:0% +we'll just get one because this t- mu is + + + align:start position:0% +we'll just get one because this t- mu is +is like an averaging operator. + + align:start position:0% +is like an averaging operator. + + + align:start position:0% +is like an averaging operator. +We're averaging t. So, t mu of f at g is + + align:start position:0% +We're averaging t. So, t mu of f at g is + + + align:start position:0% +We're averaging t. So, t mu of f at g is +the average value at of g at some other + + align:start position:0% +the average value at of g at some other + + + align:start position:0% +the average value at of g at some other +places around g that are dictated by mu. + + align:start position:0% +places around g that are dictated by mu. + + + align:start position:0% +places around g that are dictated by mu. +So t mu of one is one. + + align:start position:0% +So t mu of one is one. + + + align:start position:0% +So t mu of one is one. +Okay. And um now it's uh okay. So so + + align:start position:0% +Okay. And um now it's uh okay. So so + + + align:start position:0% +Okay. And um now it's uh okay. So so +that implies that the that the the Okay. + + align:start position:0% +that implies that the that the the Okay. + + + align:start position:0% +that implies that the that the the Okay. +So I'll do a little lema. + + align:start position:0% +So I'll do a little lema. + + + align:start position:0% +So I'll do a little lema. +The the the largest singular value. + + align:start position:0% + + + + align:start position:0% + +Yeah. Okay. So little lema is that t mu + + align:start position:0% +Yeah. Okay. So little lema is that t mu + + + align:start position:0% +Yeah. Okay. So little lema is that t mu +of f and l2 is at most f and l2 and this + + align:start position:0% +of f and l2 is at most f and l2 and this + + + align:start position:0% +of f and l2 is at most f and l2 and this +is sharp because of this example. + + align:start position:0% +is sharp because of this example. + + + align:start position:0% +is sharp because of this example. +They could be they could be equal. + + align:start position:0% +They could be they could be equal. + + + align:start position:0% +They could be they could be equal. +Okay. + + align:start position:0% + + + + align:start position:0% + +Okay. So proving this will help us think + + align:start position:0% +Okay. So proving this will help us think + + + align:start position:0% +Okay. So proving this will help us think +a little bit about what convolution + + align:start position:0% +a little bit about what convolution + + + align:start position:0% +a little bit about what convolution +means. Um so t mu of f is f convolved + + align:start position:0% +means. Um so t mu of f is f convolved + + + align:start position:0% +means. Um so t mu of f is f convolved +with mu + + align:start position:0% +with mu + + + align:start position:0% +with mu +g here. + + align:start position:0% +g here. + + + align:start position:0% +g here. +So that's the sum g1 g2 = g f of g1 mu + + align:start position:0% +So that's the sum g1 g2 = g f of g1 mu + + + align:start position:0% +So that's the sum g1 g2 = g f of g1 mu +of g2. + + align:start position:0% +of g2. + + + align:start position:0% +of g2. +And I'd like to think of this as a sum + + align:start position:0% +And I'd like to think of this as a sum + + + align:start position:0% +And I'd like to think of this as a sum +over g2. So it's the sum over g2 because + + align:start position:0% +over g2. So it's the sum over g2 because + + + align:start position:0% +over g2. So it's the sum over g2 because +I'm thinking of it that way. I can bring + + align:start position:0% +I'm thinking of it that way. I can bring + + + align:start position:0% +I'm thinking of it that way. I can bring +the mu of g2 out front and then what I + + align:start position:0% +the mu of g2 out front and then what I + + + align:start position:0% +the mu of g2 out front and then what I +have left is f of g1 which is g * g2 + + align:start position:0% +have left is f of g1 which is g * g2 + + + align:start position:0% +have left is f of g1 which is g * g2 +inverse + + align:start position:0% + + + + align:start position:0% + +and I want to think of this as a linear + + align:start position:0% +and I want to think of this as a linear + + + align:start position:0% +and I want to think of this as a linear +combination of a bunch of different + + align:start position:0% +combination of a bunch of different + + + align:start position:0% +combination of a bunch of different +functions of g. + + align:start position:0% +functions of g. + + + align:start position:0% +functions of g. +Okay, let's give them a name. So this + + align:start position:0% +Okay, let's give them a name. So this + + + align:start position:0% +Okay, let's give them a name. So this +function of g is sort of f but but we + + align:start position:0% +function of g is sort of f but but we + + + align:start position:0% +function of g is sort of f but but we +first did this thing and I want I want + + align:start position:0% +first did this thing and I want I want + + + align:start position:0% +first did this thing and I want I want +you to think of it as taking f and then + + align:start position:0% +you to think of it as taking f and then + + + align:start position:0% +you to think of it as taking f and then +shifting it using the group. So it's the + + align:start position:0% +shifting it using the group. So it's the + + + align:start position:0% +shifting it using the group. So it's the +right translation by g2 of f of g is + + align:start position:0% +right translation by g2 of f of g is + + + align:start position:0% +right translation by g2 of f of g is +defined to be this thing here. + + align:start position:0% +defined to be this thing here. + + + align:start position:0% +defined to be this thing here. +So we could plug that in. Um and this + + align:start position:0% +So we could plug that in. Um and this + + + align:start position:0% +So we could plug that in. Um and this +shifting operation doesn't change the + + align:start position:0% +shifting operation doesn't change the + + + align:start position:0% +shifting operation doesn't change the +norm of g. So, RG2 of F in L2 is the + + align:start position:0% +norm of g. So, RG2 of F in L2 is the + + + align:start position:0% +norm of g. So, RG2 of F in L2 is the +same as F in R2. + + align:start position:0% + + + + align:start position:0% + +Ah, I've been mentioning L2. What? Yeah, + + align:start position:0% +Ah, I've been mentioning L2. What? Yeah, + + + align:start position:0% +Ah, I've been mentioning L2. What? Yeah, +I should say. + + align:start position:0% +I should say. + + + align:start position:0% +I should say. +Okay, let me pause for a second. I + + align:start position:0% +Okay, let me pause for a second. I + + + align:start position:0% +Okay, let me pause for a second. I +should have said something before. + + align:start position:0% +should have said something before. + + + align:start position:0% +should have said something before. +[Applause] + + align:start position:0% + + + + align:start position:0% + +Okay, so when we have these functions on + + align:start position:0% +Okay, so when we have these functions on + + + align:start position:0% +Okay, so when we have these functions on +G, we're going to measure their norm. + + align:start position:0% +G, we're going to measure their norm. + + + align:start position:0% +G, we're going to measure their norm. +Um, and if I have f L2 of G, this is + + align:start position:0% +Um, and if I have f L2 of G, this is + + + align:start position:0% +Um, and if I have f L2 of G, this is +going to be some G and G, f of gum + + align:start position:0% +going to be some G and G, f of gum + + + align:start position:0% +going to be some G and G, f of gum +squared to the 12. Or I could take an + + align:start position:0% +squared to the 12. Or I could take an + + + align:start position:0% +squared to the 12. Or I could take an +inner product, the inner product of + + align:start position:0% +inner product, the inner product of + + + align:start position:0% +inner product, the inner product of +f_sub_1 and f_sub_2 is the sum g and g, + + align:start position:0% +f_sub_1 and f_sub_2 is the sum g and g, + + + align:start position:0% +f_sub_1 and f_sub_2 is the sum g and g, +f_sub_1 of g, f_sub_2 of g to that. So + + align:start position:0% +f_sub_1 of g, f_sub_2 of g to that. So + + + align:start position:0% +f_sub_1 of g, f_sub_2 of g to that. So +the functions on g are I hope we're + + align:start position:0% +the functions on g are I hope we're + + + align:start position:0% +the functions on g are I hope we're +spaced with this with this natural + + align:start position:0% +spaced with this with this natural + + + align:start position:0% +spaced with this with this natural +measure. Okay. Um so then if I take a + + align:start position:0% +measure. Okay. Um so then if I take a + + + align:start position:0% +measure. Okay. Um so then if I take a +function and I + + align:start position:0% +function and I + + + align:start position:0% +function and I +translate it or do this right + + align:start position:0% +translate it or do this right + + + align:start position:0% +translate it or do this right +translation um it just sort of permutes + + align:start position:0% +translation um it just sort of permutes + + + align:start position:0% +translation um it just sort of permutes +the value so it doesn't change this + + align:start position:0% +the value so it doesn't change this + + + align:start position:0% +the value so it doesn't change this +thing. + + align:start position:0% +thing. + + + align:start position:0% +thing. +Okay. So now if we look at our t mu of f + + align:start position:0% +Okay. So now if we look at our t mu of f + + + align:start position:0% +Okay. So now if we look at our t mu of f +um + + align:start position:0% +um + + + align:start position:0% +um +um I have this + + align:start position:0% + + + + align:start position:0% + +yeah + + align:start position:0% + + + + align:start position:0% + +I'm interested in the norm of t mu of f. + + align:start position:0% +I'm interested in the norm of t mu of f. + + + align:start position:0% +I'm interested in the norm of t mu of f. +This is the norm of the sum on G2 mu of + + align:start position:0% +This is the norm of the sum on G2 mu of + + + align:start position:0% +This is the norm of the sum on G2 mu of +G2 + + align:start position:0% +G2 + + + align:start position:0% +G2 +R subg2 of F. + + align:start position:0% +R subg2 of F. + + + align:start position:0% +R subg2 of F. +It's a linear combination of these + + align:start position:0% +It's a linear combination of these + + + align:start position:0% +It's a linear combination of these +functions which are all translates of F. + + align:start position:0% +functions which are all translates of F. + + + align:start position:0% +functions which are all translates of F. +And L2 is a norm. It obeys the triangle + + align:start position:0% +And L2 is a norm. It obeys the triangle + + + align:start position:0% +And L2 is a norm. It obeys the triangle +inequality. So this is less than the sum + + align:start position:0% +inequality. So this is less than the sum + + + align:start position:0% +inequality. So this is less than the sum +on G2 mu of G2 + + align:start position:0% +on G2 mu of G2 + + + align:start position:0% +on G2 mu of G2 +RG2 of F and L2. All of these have the + + align:start position:0% +RG2 of F and L2. All of these have the + + + align:start position:0% +RG2 of F and L2. All of these have the +same norm. + + align:start position:0% + + + + align:start position:0% + +which is the L2 norm of F and the L2 + + align:start position:0% +which is the L2 norm of F and the L2 + + + align:start position:0% +which is the L2 norm of F and the L2 +norm and then this adds up to one. So + + align:start position:0% +norm and then this adds up to one. So + + + align:start position:0% +norm and then this adds up to one. So +this is just the L2 norm of F. + + align:start position:0% + + + + align:start position:0% + +Okay, + + align:start position:0% +Okay, + + + align:start position:0% +Okay, +so this is a basic fact about averaging + + align:start position:0% +so this is a basic fact about averaging + + + align:start position:0% +so this is a basic fact about averaging +operators. Um and + + align:start position:0% +operators. Um and + + + align:start position:0% +operators. Um and +to understand whether the random walk is + + align:start position:0% +to understand whether the random walk is + + + align:start position:0% +to understand whether the random walk is +mixing things up, we have to care about + + align:start position:0% +mixing things up, we have to care about + + + align:start position:0% +mixing things up, we have to care about +how it behaves on the space orthogonal + + align:start position:0% +how it behaves on the space orthogonal + + + align:start position:0% +how it behaves on the space orthogonal +to one. And the first observation is + + align:start position:0% +to one. And the first observation is + + + align:start position:0% +to one. And the first observation is +that it preserves the space orthogonal + + align:start position:0% +that it preserves the space orthogonal + + + align:start position:0% +that it preserves the space orthogonal +to one. So let's give that space a name. + + align:start position:0% +to one. So let's give that space a name. + + + align:start position:0% +to one. So let's give that space a name. +Say L2 of G KN is the set of F and L2 of + + align:start position:0% +Say L2 of G KN is the set of F and L2 of + + + align:start position:0% +Say L2 of G KN is the set of F and L2 of +G. + + align:start position:0% +G. + + + align:start position:0% +G. +So that + + align:start position:0% +So that + + + align:start position:0% +So that +sum G and G of F of G is zero. This is + + align:start position:0% +sum G and G of F of G is zero. This is + + + align:start position:0% +sum G and G of F of G is zero. This is +saying that f is orthogonal to the + + align:start position:0% +saying that f is orthogonal to the + + + align:start position:0% +saying that f is orthogonal to the +constant function. + + align:start position:0% +constant function. + + + align:start position:0% +constant function. +Okay. So another simple lema is that our + + align:start position:0% +Okay. So another simple lema is that our + + + align:start position:0% +Okay. So another simple lema is that our +operator t mu actually takes this space + + align:start position:0% +operator t mu actually takes this space + + + align:start position:0% +operator t mu actually takes this space +to itself. So it takes the constant + + align:start position:0% +to itself. So it takes the constant + + + align:start position:0% +to itself. So it takes the constant +function to itself and it takes the + + align:start position:0% +function to itself and it takes the + + + align:start position:0% +function to itself and it takes the +perpendicular space to itself which will + + align:start position:0% +perpendicular space to itself which will + + + align:start position:0% +perpendicular space to itself which will +imply that the constant function is one + + align:start position:0% +imply that the constant function is one + + + align:start position:0% +imply that the constant function is one +of the singular vectors of the of of + + align:start position:0% +of the singular vectors of the of of + + + align:start position:0% +of the singular vectors of the of of +this operator. + + align:start position:0% +this operator. + + + align:start position:0% +this operator. +Okay. So proof + + align:start position:0% +Okay. So proof + + + align:start position:0% +Okay. So proof +um uh + + align:start position:0% +um uh + + + align:start position:0% +um uh +so I want to understand the sum g and g + + align:start position:0% +so I want to understand the sum g and g + + + align:start position:0% +so I want to understand the sum g and g +of t team muf of g. Going to imagine + + align:start position:0% +of t team muf of g. Going to imagine + + + align:start position:0% +of t team muf of g. Going to imagine +that the sum of f of g is zero. And I + + align:start position:0% +that the sum of f of g is zero. And I + + + align:start position:0% +that the sum of f of g is zero. And I +want to see if that's still true. All + + align:start position:0% +want to see if that's still true. All + + + align:start position:0% +want to see if that's still true. All +right. So that's the sum g and g sum g1 + + align:start position:0% +right. So that's the sum g and g sum g1 + + + align:start position:0% +right. So that's the sum g and g sum g1 +* g2 equals g. f of g1 mu of g2. + + align:start position:0% +* g2 equals g. f of g1 mu of g2. + + + align:start position:0% +* g2 equals g. f of g1 mu of g2. +And if you think about what we're + + align:start position:0% +And if you think about what we're + + + align:start position:0% +And if you think about what we're +summing over, we're just summing over G1 + + align:start position:0% +summing over, we're just summing over G1 + + + align:start position:0% +summing over, we're just summing over G1 +and G2. + + align:start position:0% +and G2. + + + align:start position:0% +and G2. +So this is the sum over G1 and G2 of F + + align:start position:0% +So this is the sum over G1 and G2 of F + + + align:start position:0% +So this is the sum over G1 and G2 of F +of G1, mu of G2. And now that factors. + + align:start position:0% + + + + align:start position:0% + +So this is one. And if F was in L2 of + + align:start position:0% +So this is one. And if F was in L2 of + + + align:start position:0% +So this is one. And if F was in L2 of +GN, this would be zero. + + align:start position:0% + + + + align:start position:0% + +This is + + align:start position:0% +This is + + + align:start position:0% +This is +so f if f is an l2 of g not then so t mu + + align:start position:0% +so f if f is an l2 of g not then so t mu + + + align:start position:0% +so f if f is an l2 of g not then so t mu +of f will be + + align:start position:0% +of f will be + + + align:start position:0% +of f will be +okay Oh, + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% + + + + align:start position:0% + +all right. So, so we've seen that um + + align:start position:0% +all right. So, so we've seen that um + + + align:start position:0% +all right. So, so we've seen that um +t mu of one is one and t mu takes l2 of + + align:start position:0% +t mu of one is one and t mu takes l2 of + + + align:start position:0% +t mu of one is one and t mu takes l2 of +g kn to itself. + + align:start position:0% +g kn to itself. + + + align:start position:0% +g kn to itself. +So this is the largest singular value + + align:start position:0% +So this is the largest singular value + + + align:start position:0% +So this is the largest singular value +we've seen and um and then here there's + + align:start position:0% +we've seen and um and then here there's + + + align:start position:0% +we've seen and um and then here there's +something else. So let's say sigma one + + align:start position:0% +something else. So let's say sigma one + + + align:start position:0% +something else. So let's say sigma one +of t mu. + + align:start position:0% +of t mu. + + + align:start position:0% +of t mu. +So, so this this one could I'll call it + + align:start position:0% +So, so this this one could I'll call it + + + align:start position:0% +So, so this this one could I'll call it +sigma kn of t mu. Somehow in this + + align:start position:0% +sigma kn of t mu. Somehow in this + + + align:start position:0% +sigma kn of t mu. Somehow in this +setting the one is sort of trivial and + + align:start position:0% +setting the one is sort of trivial and + + + align:start position:0% +setting the one is sort of trivial and +everything else will depend on the trace + + align:start position:0% +everything else will depend on the trace + + + align:start position:0% +everything else will depend on the trace +of mu. So sigma 1 of t mu is the largest + + align:start position:0% +of mu. So sigma 1 of t mu is the largest + + + align:start position:0% +of mu. So sigma 1 of t mu is the largest +singular value + + align:start position:0% + + + + align:start position:0% + +of of this part. + + align:start position:0% +of of this part. + + + align:start position:0% +of of this part. +Okay. + + align:start position:0% +Okay. + + + align:start position:0% +Okay. +All right. So question two is going to + + align:start position:0% +All right. So question two is going to + + + align:start position:0% +All right. So question two is going to +be to estimate that + + align:start position:0% +be to estimate that + + + align:start position:0% +be to estimate that +estimate sigma one of t and these two + + align:start position:0% +estimate sigma one of t and these two + + + align:start position:0% +estimate sigma one of t and these two +questions are related to each other. Um + + align:start position:0% +questions are related to each other. Um + + + align:start position:0% +questions are related to each other. Um +this thing helps to understand um how I + + align:start position:0% +this thing helps to understand um how I + + + align:start position:0% +this thing helps to understand um how I +mean helps a lot to understand how this + + align:start position:0% +mean helps a lot to understand how this + + + align:start position:0% +mean helps a lot to understand how this +operator behaves and and to and to + + align:start position:0% +operator behaves and and to and to + + + align:start position:0% +operator behaves and and to and to +answer question one. So let me put up a + + align:start position:0% +answer question one. So let me put up a + + + align:start position:0% +answer question one. So let me put up a +simple proposition how question two is + + align:start position:0% +simple proposition how question two is + + + align:start position:0% +simple proposition how question two is +related to question one. + + align:start position:0% +related to question one. + + + align:start position:0% +related to question one. +So proposition if you look at that thing + + align:start position:0% +So proposition if you look at that thing + + + align:start position:0% +So proposition if you look at that thing +t mu to the k delta function g minus 1 / + + align:start position:0% +t mu to the k delta function g minus 1 / + + + align:start position:0% +t mu to the k delta function g minus 1 / +g in l2 this is bounded by sigma 1 of t + + align:start position:0% +g in l2 this is bounded by sigma 1 of t + + + align:start position:0% +g in l2 this is bounded by sigma 1 of t +mu to the k. + + align:start position:0% + + + + align:start position:0% + +Okay so proof. + + align:start position:0% +Okay so proof. + + + align:start position:0% +Okay so proof. +So we want to see what t mu to the k + + align:start position:0% +So we want to see what t mu to the k + + + align:start position:0% +So we want to see what t mu to the k +does to a delta function at a point. + + align:start position:0% +does to a delta function at a point. + + + align:start position:0% +does to a delta function at a point. +Let's take this delta function at a + + align:start position:0% +Let's take this delta function at a + + + align:start position:0% +Let's take this delta function at a +point and t mu splits up the constant + + align:start position:0% +point and t mu splits up the constant + + + align:start position:0% +point and t mu splits up the constant +function is an igen function and then + + align:start position:0% +function is an igen function and then + + + align:start position:0% +function is an igen function and then +and then then the the the things with + + align:start position:0% +and then then the the the things with + + + align:start position:0% +and then then the the the things with +mean zero. So let's split up this delta + + align:start position:0% +mean zero. So let's split up this delta + + + align:start position:0% +mean zero. So let's split up this delta +function. So the the + + align:start position:0% +function. So the the + + + align:start position:0% +function. So the the +constant part of it is like this and + + align:start position:0% +constant part of it is like this and + + + align:start position:0% +constant part of it is like this and +then we have this. + + align:start position:0% +then we have this. + + + align:start position:0% +then we have this. +So the reason we split it up that way is + + align:start position:0% +So the reason we split it up that way is + + + align:start position:0% +So the reason we split it up that way is +that this part which in the beginning of + + align:start position:0% +that this part which in the beginning of + + + align:start position:0% +that this part which in the beginning of +the class we could have we would have + + align:start position:0% +the class we could have we would have + + + align:start position:0% +the class we could have we would have +called like the high part of this um so + + align:start position:0% +called like the high part of this um so + + + align:start position:0% +called like the high part of this um so +I guess I'll do that that's in L2 of G 0 + + align:start position:0% +I guess I'll do that that's in L2 of G 0 + + + align:start position:0% +I guess I'll do that that's in L2 of G 0 +mean zero part okay now what happens + + align:start position:0% +mean zero part okay now what happens + + + align:start position:0% +mean zero part okay now what happens +when we apply this operator well this + + align:start position:0% +when we apply this operator well this + + + align:start position:0% +when we apply this operator well this +operator takes constants to constants + + align:start position:0% +operator takes constants to constants + + + align:start position:0% +operator takes constants to constants +uh it's the identity on the constant + + align:start position:0% +uh it's the identity on the constant + + + align:start position:0% +uh it's the identity on the constant +part um and so I take t mu to the k + + align:start position:0% +part um and so I take t mu to the k + + + align:start position:0% +part um and so I take t mu to the k +delta g kn + + align:start position:0% +delta g kn + + + align:start position:0% +delta g kn +this part will say stay stay like one + + align:start position:0% +this part will say stay stay like one + + + align:start position:0% +this part will say stay stay like one +over one over I'll take the left hand + + align:start position:0% +over one over I'll take the left hand + + + align:start position:0% +over one over I'll take the left hand +side and then if I subtract that it will + + align:start position:0% +side and then if I subtract that it will + + + align:start position:0% +side and then if I subtract that it will +disappear so what I'll be left with is t + + align:start position:0% +disappear so what I'll be left with is t + + + align:start position:0% +disappear so what I'll be left with is t +mu to the k on + + align:start position:0% +mu to the k on + + + align:start position:0% +mu to the k on +this uh high part of the delta g not + + align:start position:0% +this uh high part of the delta g not + + + align:start position:0% +this uh high part of the delta g not +okay how big is that well this part + + align:start position:0% +okay how big is that well this part + + + align:start position:0% +okay how big is that well this part +lives in this space so we can bound the + + align:start position:0% +lives in this space so we can bound the + + + align:start position:0% +lives in this space so we can bound the +size of this thing using the uh singular + + align:start position:0% +size of this thing using the uh singular + + + align:start position:0% +size of this thing using the uh singular +vector. Um and so so + + align:start position:0% +vector. Um and so so + + + align:start position:0% +vector. Um and so so +I get t mu + + align:start position:0% +I get t mu + + + align:start position:0% +I get t mu +to the k + + align:start position:0% +to the k + + + align:start position:0% +to the k +of delta g high + + align:start position:0% +of delta g high + + + align:start position:0% +of delta g high +two that's bounded by + + align:start position:0% +two that's bounded by + + + align:start position:0% +two that's bounded by +sigma 1 of t mu to the k + + align:start position:0% +sigma 1 of t mu to the k + + + align:start position:0% +sigma 1 of t mu to the k +times delta g high2 + + align:start position:0% + + + + align:start position:0% + +Okay. And now it's it's also now + + align:start position:0% +Okay. And now it's it's also now + + + align:start position:0% +Okay. And now it's it's also now +straightforward to check that this is + + align:start position:0% +straightforward to check that this is + + + align:start position:0% +straightforward to check that this is +smaller than one. + + align:start position:0% + + + + align:start position:0% + +Okay. + + align:start position:0% +Okay. + + + align:start position:0% +Okay. +So uh it's an application um + + align:start position:0% +So uh it's an application um + + + align:start position:0% +So uh it's an application um +if we were able to arrange that sigma 1 + + align:start position:0% +if we were able to arrange that sigma 1 + + + align:start position:0% +if we were able to arrange that sigma 1 +t mu to the k was less than 1 over 100 + + align:start position:0% +t mu to the k was less than 1 over 100 + + + align:start position:0% +t mu to the k was less than 1 over 100 +times the size of g + + align:start position:0% +times the size of g + + + align:start position:0% +times the size of g +um then well this l2 norm would be less + + align:start position:0% +um then well this l2 norm would be less + + + align:start position:0% +um then well this l2 norm would be less +than one over 100 times the size of g + + align:start position:0% +than one over 100 times the size of g + + + align:start position:0% +than one over 100 times the size of g +and so in particular the l infinity norm + + align:start position:0% +and so in particular the l infinity norm + + + align:start position:0% +and so in particular the l infinity norm +would be less than one over 100 times + + align:start position:0% +would be less than one over 100 times + + + align:start position:0% +would be less than one over 100 times +the size of g. So then I would say that + + align:start position:0% +the size of g. So then I would say that + + + align:start position:0% +the size of g. So then I would say that +for every g um + + align:start position:0% +for every g um + + + align:start position:0% +for every g um +t mu k delta g of g minus one over the + + align:start position:0% +t mu k delta g of g minus one over the + + + align:start position:0% +t mu k delta g of g minus one over the +size of g would be smaller than 1 over + + align:start position:0% +size of g would be smaller than 1 over + + + align:start position:0% +size of g would be smaller than 1 over +100 times the size of g. That would tell + + align:start position:0% +100 times the size of g. That would tell + + + align:start position:0% +100 times the size of g. That would tell +us say that this function is pretty + + align:start position:0% +us say that this function is pretty + + + align:start position:0% +us say that this function is pretty +close to this constant function within + + align:start position:0% +close to this constant function within + + + align:start position:0% +close to this constant function within +1%. So that random walk would now have + + align:start position:0% +1%. So that random walk would now have + + + align:start position:0% +1%. So that random walk would now have +mixed uh pretty thoroughly. + + align:start position:0% + + + + align:start position:0% + +Okay, great. So if we can get our hands + + align:start position:0% +Okay, great. So if we can get our hands + + + align:start position:0% +Okay, great. So if we can get our hands +on sigma 1 of t mu, then we can figure + + align:start position:0% +on sigma 1 of t mu, then we can figure + + + align:start position:0% +on sigma 1 of t mu, then we can figure +out how long it takes this random walk + + align:start position:0% +out how long it takes this random walk + + + align:start position:0% +out how long it takes this random walk +to mix evenly. + + align:start position:0% + + + + align:start position:0% + +Cool. + + align:start position:0% + + + + align:start position:0% + +Okay. + + align:start position:0% +Okay. + + + align:start position:0% +Okay. +So now let me mention tell you an + + align:start position:0% +So now let me mention tell you an + + + align:start position:0% +So now let me mention tell you an +interesting example of a particular + + align:start position:0% +interesting example of a particular + + + align:start position:0% +interesting example of a particular +group and a particular mu where there's + + align:start position:0% +group and a particular mu where there's + + + align:start position:0% +group and a particular mu where there's +a cool estimate for this + + align:start position:0% + + + + align:start position:0% + +So we are going to mostly focus or maybe + + align:start position:0% +So we are going to mostly focus or maybe + + + align:start position:0% +So we are going to mostly focus or maybe +only focus on the group SL2 of FP + + align:start position:0% + + + + align:start position:0% + +and um could pick many different + + align:start position:0% +and um could pick many different + + + align:start position:0% +and um could pick many different +measures for a random walk but one nice + + align:start position:0% +measures for a random walk but one nice + + + align:start position:0% +measures for a random walk but one nice +one which has been studied is to take + + align:start position:0% +one which has been studied is to take + + + align:start position:0% +one which has been studied is to take +the set A to be so f so first of all um + + align:start position:0% +the set A to be so f so first of all um + + + align:start position:0% +the set A to be so f so first of all um +if A is a subset of G. There's a natural + + align:start position:0% +if A is a subset of G. There's a natural + + + align:start position:0% +if A is a subset of G. There's a natural +measure on A which is the uniform + + align:start position:0% +measure on A which is the uniform + + + align:start position:0% +measure on A which is the uniform +measure. So measure on A which is one + + align:start position:0% +measure. So measure on A which is one + + + align:start position:0% +measure. So measure on A which is one +over the cardality of A times the sum A + + align:start position:0% +over the cardality of A times the sum A + + + align:start position:0% +over the cardality of A times the sum A +and A of delta A. + + align:start position:0% +and A of delta A. + + + align:start position:0% +and A of delta A. +Okay. Um okay. So there's a nice set A + + align:start position:0% +Okay. Um okay. So there's a nice set A + + + align:start position:0% +Okay. Um okay. So there's a nice set A +inside of here which was studied by + + align:start position:0% +inside of here which was studied by + + + align:start position:0% +inside of here which was studied by +Selberg. A Selberg. + + align:start position:0% +Selberg. A Selberg. + + + align:start position:0% +Selberg. A Selberg. +Uh + + align:start position:0% +Uh + + + align:start position:0% +Uh +well okay which is relevant to a theorem + + align:start position:0% +well okay which is relevant to a theorem + + + align:start position:0% +well okay which is relevant to a theorem +of Selberg. P set his third differently. + + align:start position:0% +of Selberg. P set his third differently. + + + align:start position:0% +of Selberg. P set his third differently. +But + + align:start position:0% + + + + align:start position:0% + +so there are four elements in this set. + + align:start position:0% +so there are four elements in this set. + + + align:start position:0% +so there are four elements in this set. +Um and these are generators of the group + + align:start position:0% +Um and these are generators of the group + + + align:start position:0% +Um and these are generators of the group +SL2FP. There are many ways you could + + align:start position:0% +SL2FP. There are many ways you could + + + align:start position:0% +SL2FP. There are many ways you could +choose generators for this group, but + + align:start position:0% +choose generators for this group, but + + + align:start position:0% +choose generators for this group, but +this is probably the simplest way. + + align:start position:0% +this is probably the simplest way. + + + align:start position:0% +this is probably the simplest way. +Um + + align:start position:0% +Um + + + align:start position:0% +Um +and okay and now I can state a theorem. + + align:start position:0% +and okay and now I can state a theorem. + + + align:start position:0% +and okay and now I can state a theorem. +So theorem one exists a positive c I + + align:start position:0% +So theorem one exists a positive c I + + + align:start position:0% +So theorem one exists a positive c I +think one one over 100 should be fine. + + align:start position:0% +think one one over 100 should be fine. + + + align:start position:0% +think one one over 100 should be fine. +Um so that + + align:start position:0% +Um so that + + + align:start position:0% +Um so that +for every p prime if you take a selberg + + align:start position:0% +for every p prime if you take a selberg + + + align:start position:0% +for every p prime if you take a selberg +and sl2 of fp you make a random walk. Um + + align:start position:0% +and sl2 of fp you make a random walk. Um + + + align:start position:0% +and sl2 of fp you make a random walk. Um +and so in this setting let me write t a + + align:start position:0% +and so in this setting let me write t a + + + align:start position:0% +and so in this setting let me write t a +for t sub mu sub a. + + align:start position:0% +for t sub mu sub a. + + + align:start position:0% +for t sub mu sub a. +um then + + align:start position:0% +um then + + + align:start position:0% +um then +sigma 1 of ta is less than 1 minus c. So + + align:start position:0% +sigma 1 of ta is less than 1 minus c. So + + + align:start position:0% +sigma 1 of ta is less than 1 minus c. So +uniformly for all primes. + + align:start position:0% + + + + align:start position:0% + +So if this is say 99 over 100 then you + + align:start position:0% +So if this is say 99 over 100 then you + + + align:start position:0% +So if this is say 99 over 100 then you +can just read off uh you know high + + align:start position:0% +can just read off uh you know high + + + align:start position:0% +can just read off uh you know high +powers of this are bounded by something + + align:start position:0% +powers of this are bounded by something + + + align:start position:0% +powers of this are bounded by something +and you can plug that into the + + align:start position:0% +and you can plug that into the + + + align:start position:0% +and you can plug that into the +discussion over here. So it says that + + align:start position:0% +discussion over here. So it says that + + + align:start position:0% +discussion over here. So it says that +that random walk mixes extremely fast. + + align:start position:0% +that random walk mixes extremely fast. + + + align:start position:0% +that random walk mixes extremely fast. +Yeah. + + align:start position:0% +Yeah. + + + align:start position:0% +Yeah. +>> How does sigma one behave kind of as it + + align:start position:0% +>> How does sigma one behave kind of as it + + + align:start position:0% +>> How does sigma one behave kind of as it +over time? Does it converge to sub or + + align:start position:0% +over time? Does it converge to sub or + + + align:start position:0% +over time? Does it converge to sub or +oscillate a lot? + + align:start position:0% +oscillate a lot? + + + align:start position:0% +oscillate a lot? +>> Um so the question is how does sigma 1 + + align:start position:0% +>> Um so the question is how does sigma 1 + + + align:start position:0% +>> Um so the question is how does sigma 1 +of ta behave um as as the prime varies? + + align:start position:0% +of ta behave um as as the prime varies? + + + align:start position:0% +of ta behave um as as the prime varies? +I do not know the answer to that + + align:start position:0% +I do not know the answer to that + + + align:start position:0% +I do not know the answer to that +question. + + align:start position:0% + + + + align:start position:0% + +Um so I should say so let me say that + + align:start position:0% +Um so I should say so let me say that + + + align:start position:0% +Um so I should say so let me say that +this was this is a correlary of a + + align:start position:0% +this was this is a correlary of a + + + align:start position:0% +this was this is a correlary of a +theorem of Selberg + + align:start position:0% + + + + align:start position:0% + +from the late 50s + + align:start position:0% + + + + align:start position:0% + +um and Selberg act's actual theorem is + + align:start position:0% +um and Selberg act's actual theorem is + + + align:start position:0% +um and Selberg act's actual theorem is +about the first igen value of the + + align:start position:0% +about the first igen value of the + + + align:start position:0% +about the first igen value of the +lelassian on a hyperbolic surface which + + align:start position:0% +lelassian on a hyperbolic surface which + + + align:start position:0% +lelassian on a hyperbolic surface which +is associated to this group + + align:start position:0% +is associated to this group + + + align:start position:0% +is associated to this group +and you can go back and forth. With + + align:start position:0% +and you can go back and forth. With + + + align:start position:0% +and you can go back and forth. With +modern technology, it's considered not + + align:start position:0% +modern technology, it's considered not + + + align:start position:0% +modern technology, it's considered not +very difficult to go back and forth + + align:start position:0% +very difficult to go back and forth + + + align:start position:0% +very difficult to go back and forth +between a bound for the igen value of + + align:start position:0% +between a bound for the igen value of + + + align:start position:0% +between a bound for the igen value of +the surface and a bound here. Uh but + + align:start position:0% +the surface and a bound here. Uh but + + + align:start position:0% +the surface and a bound here. Uh but +when you do go back and forth, you will + + align:start position:0% +when you do go back and forth, you will + + + align:start position:0% +when you do go back and forth, you will +screw up the constants. + + align:start position:0% +screw up the constants. + + + align:start position:0% +screw up the constants. +Um Selberg's theorem was that the first + + align:start position:0% +Um Selberg's theorem was that the first + + + align:start position:0% +Um Selberg's theorem was that the first +igen value of that surface was at least + + align:start position:0% +igen value of that surface was at least + + + align:start position:0% +igen value of that surface was at least +316s + + align:start position:0% +316s + + + align:start position:0% +316s +and that's probably not the right + + align:start position:0% +and that's probably not the right + + + align:start position:0% +and that's probably not the right +answer. And he conjectured that it + + align:start position:0% +answer. And he conjectured that it + + + align:start position:0% +answer. And he conjectured that it +should be a quarter. + + align:start position:0% +should be a quarter. + + + align:start position:0% +should be a quarter. +Um so for his actual problem there was + + align:start position:0% +Um so for his actual problem there was + + + align:start position:0% +Um so for his actual problem there was +there is a beautiful conjecture about + + align:start position:0% +there is a beautiful conjecture about + + + align:start position:0% +there is a beautiful conjecture about +what happens as p goes to infinity which + + align:start position:0% +what happens as p goes to infinity which + + + align:start position:0% +what happens as p goes to infinity which +is that the values should converge to a + + align:start position:0% +is that the values should converge to a + + + align:start position:0% +is that the values should converge to a +quarter + + align:start position:0% +quarter + + + align:start position:0% +quarter +um for this I'm not sure + + align:start position:0% + + + + align:start position:0% + +okay cool + + align:start position:0% + + + + align:start position:0% + +okay so bounds like this are also + + align:start position:0% +okay so bounds like this are also + + + align:start position:0% +okay so bounds like this are also +related to uh expand standard graphs, + + align:start position:0% +related to uh expand standard graphs, + + + align:start position:0% +related to uh expand standard graphs, +isoparametric inequalities in graphs and + + align:start position:0% +isoparametric inequalities in graphs and + + + align:start position:0% +isoparametric inequalities in graphs and +I thought I would also show that um and + + align:start position:0% +I thought I would also show that um and + + + align:start position:0% +I thought I would also show that um and +um so it it shows that well okay so so + + align:start position:0% +um so it it shows that well okay so so + + + align:start position:0% +um so it it shows that well okay so so +let me explain that. So we can we can if + + align:start position:0% +let me explain that. So we can we can if + + + align:start position:0% +let me explain that. So we can we can if +you have a set of of generators inside + + align:start position:0% +you have a set of of generators inside + + + align:start position:0% +you have a set of of generators inside +of a group we can use that to make a + + align:start position:0% +of a group we can use that to make a + + + align:start position:0% +of a group we can use that to make a +graph called a kaly graph. + + align:start position:0% +graph called a kaly graph. + + + align:start position:0% +graph called a kaly graph. +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +And this mixing inequality + + align:start position:0% +And this mixing inequality + + + align:start position:0% +And this mixing inequality +can be thought of or implies some + + align:start position:0% +can be thought of or implies some + + + align:start position:0% +can be thought of or implies some +interesting geometric features of the + + align:start position:0% +interesting geometric features of the + + + align:start position:0% +interesting geometric features of the +graph. + + align:start position:0% + + + + align:start position:0% + +So um + + align:start position:0% +So um + + + align:start position:0% +So um +expansion + + align:start position:0% +expansion + + + align:start position:0% +expansion +in graphs. + + align:start position:0% + + + + align:start position:0% + +Okay. So if G is a finite group + + align:start position:0% +Okay. So if G is a finite group + + + align:start position:0% +Okay. So if G is a finite group +then A is a set of generators + + align:start position:0% + + + + align:start position:0% + +and I guess that to have a graph maybe + + align:start position:0% +and I guess that to have a graph maybe + + + align:start position:0% +and I guess that to have a graph maybe +we should say that is a symmetric set of + + align:start position:0% +we should say that is a symmetric set of + + + align:start position:0% +we should say that is a symmetric set of +generators. I don't know if that's + + align:start position:0% +generators. I don't know if that's + + + align:start position:0% +generators. I don't know if that's +important. Yeah, let's leave it. + + align:start position:0% +important. Yeah, let's leave it. + + + align:start position:0% +important. Yeah, let's leave it. +Um + + align:start position:0% +Um + + + align:start position:0% +Um +then we'll have a kaly graph kaly graph + + align:start position:0% +then we'll have a kaly graph kaly graph + + + align:start position:0% +then we'll have a kaly graph kaly graph +of GA. This is a graph. + + align:start position:0% +of GA. This is a graph. + + + align:start position:0% +of GA. This is a graph. +The vertices + + align:start position:0% +The vertices + + + align:start position:0% +The vertices +are G and G. And a pair G1, G2 + + align:start position:0% +are G and G. And a pair G1, G2 + + + align:start position:0% +are G and G. And a pair G1, G2 +um is an edge + + align:start position:0% +um is an edge + + + align:start position:0% +um is an edge +if and only if um G2 is G1 * A or vice + + align:start position:0% +if and only if um G2 is G1 * A or vice + + + align:start position:0% +if and only if um G2 is G1 * A or vice +versa. + + align:start position:0% +versa. + + + align:start position:0% +versa. +Um yeah, so I guess we should have it + + align:start position:0% +Um yeah, so I guess we should have it + + + align:start position:0% +Um yeah, so I guess we should have it +symmetric. Um G2= G1 * A where A is in + + align:start position:0% +symmetric. Um G2= G1 * A where A is in + + + align:start position:0% +symmetric. Um G2= G1 * A where A is in +A. + + align:start position:0% +A. + + + align:start position:0% +A. +Okay. And the random walk we've been + + align:start position:0% +Okay. And the random walk we've been + + + align:start position:0% +Okay. And the random walk we've been +imagining is basically the random walk + + align:start position:0% +imagining is basically the random walk + + + align:start position:0% +imagining is basically the random walk +on this graph. You start at a vertex and + + align:start position:0% +on this graph. You start at a vertex and + + + align:start position:0% +on this graph. You start at a vertex and +you move randomly to a neighboring along + + align:start position:0% +you move randomly to a neighboring along + + + align:start position:0% +you move randomly to a neighboring along +the edges. Yeah. + + align:start position:0% +the edges. Yeah. + + + align:start position:0% +the edges. Yeah. +>> How do you identify SL2 of a finite + + align:start position:0% +>> How do you identify SL2 of a finite + + + align:start position:0% +>> How do you identify SL2 of a finite +field with a hyperbolic surface? + + align:start position:0% +field with a hyperbolic surface? + + + align:start position:0% +field with a hyperbolic surface? +>> Um yeah, I I I will Okay, we'll talk + + align:start position:0% +>> Um yeah, I I I will Okay, we'll talk + + + align:start position:0% +>> Um yeah, I I I will Okay, we'll talk +about the connection to hyperbolic + + align:start position:0% +about the connection to hyperbolic + + + align:start position:0% +about the connection to hyperbolic +geometry a little later when we talk + + align:start position:0% +geometry a little later when we talk + + + align:start position:0% +geometry a little later when we talk +about the proof of this theorem, but + + align:start position:0% +about the proof of this theorem, but + + + align:start position:0% +about the proof of this theorem, but +let's do it then. + + align:start position:0% +let's do it then. + + + align:start position:0% +let's do it then. +Yeah. Okay. + + align:start position:0% +Yeah. Okay. + + + align:start position:0% +Yeah. Okay. +Um + + align:start position:0% +Um + + + align:start position:0% +Um +okay so that's the kaly graph + + align:start position:0% +okay so that's the kaly graph + + + align:start position:0% +okay so that's the kaly graph +um + + align:start position:0% +um + + + align:start position:0% +um +and in this graph if I have subsets s + + align:start position:0% +and in this graph if I have subsets s + + + align:start position:0% +and in this graph if I have subsets s +and t inside of the vertices e of s and + + align:start position:0% +and t inside of the vertices e of s and + + + align:start position:0% +and t inside of the vertices e of s and +t the edges from s to t that's going to + + align:start position:0% +t the edges from s to t that's going to + + + align:start position:0% +t the edges from s to t that's going to +be the set of g1 g2 and s cross t so + + align:start position:0% +be the set of g1 g2 and s cross t so + + + align:start position:0% +be the set of g1 g2 and s cross t so +that g1 g2 is an edge + + align:start position:0% +that g1 g2 is an edge + + + align:start position:0% +that g1 g2 is an edge +a set of edges from fast. + + align:start position:0% +a set of edges from fast. + + + align:start position:0% +a set of edges from fast. +Okay. So, proposition + + align:start position:0% + + + + align:start position:0% + +if we have CGA is above then the number + + align:start position:0% +if we have CGA is above then the number + + + align:start position:0% +if we have CGA is above then the number +of edges from S to S complement. So, S + + align:start position:0% +of edges from S to S complement. So, S + + + align:start position:0% +of edges from S to S complement. So, S +is going to be a subset of the vertices. + + align:start position:0% +is going to be a subset of the vertices. + + + align:start position:0% +is going to be a subset of the vertices. +number of these edges is at least one + + align:start position:0% +number of these edges is at least one + + + align:start position:0% +number of these edges is at least one +minus sigma 1 of TA + + align:start position:0% + + + + align:start position:0% + +times + + align:start position:0% +times + + + align:start position:0% +times +a * S * S complement over G. + + align:start position:0% + + + + align:start position:0% + +Okay, so let's digest this a little bit. + + align:start position:0% +Okay, so let's digest this a little bit. + + + align:start position:0% +Okay, so let's digest this a little bit. +Um so what does this expression mean? + + align:start position:0% +Um so what does this expression mean? + + + align:start position:0% +Um so what does this expression mean? +Well, there are S. + + align:start position:0% +Well, there are S. + + + align:start position:0% +Well, there are S. +This is the this is how many points + + align:start position:0% +This is the this is how many points + + + align:start position:0% +This is the this is how many points +there are in the set S. From each of + + align:start position:0% +there are in the set S. From each of + + + align:start position:0% +there are in the set S. From each of +those points, there are a edges coming + + align:start position:0% +those points, there are a edges coming + + + align:start position:0% +those points, there are a edges coming +out. So, this is how many edges there + + align:start position:0% +out. So, this is how many edges there + + + align:start position:0% +out. So, this is how many edges there +are that are leaving points at S. + + align:start position:0% +are that are leaving points at S. + + + align:start position:0% +are that are leaving points at S. +How many of them do we think end up in S + + align:start position:0% +How many of them do we think end up in S + + + align:start position:0% +How many of them do we think end up in S +complement? Well, we don't really know, + + align:start position:0% +complement? Well, we don't really know, + + + align:start position:0% +complement? Well, we don't really know, +but as a reference point, + + align:start position:0% +but as a reference point, + + + align:start position:0% +but as a reference point, +everything was sort of random. The + + align:start position:0% +everything was sort of random. The + + + align:start position:0% +everything was sort of random. The +fraction of edges that ended up in S + + align:start position:0% +fraction of edges that ended up in S + + + align:start position:0% +fraction of edges that ended up in S +complement might be S complement over G. + + align:start position:0% +complement might be S complement over G. + + + align:start position:0% +complement might be S complement over G. +So this expression here would be the + + align:start position:0% +So this expression here would be the + + + align:start position:0% +So this expression here would be the +typical number of edges from S to S + + align:start position:0% +typical number of edges from S to S + + + align:start position:0% +typical number of edges from S to S +complement if we had a random graph + + align:start position:0% +complement if we had a random graph + + + align:start position:0% +complement if we had a random graph +where each vertex was in this many + + align:start position:0% +where each vertex was in this many + + + align:start position:0% +where each vertex was in this many +edges. + + align:start position:0% +edges. + + + align:start position:0% +edges. +Okay. And then we're going to say that + + align:start position:0% +Okay. And then we're going to say that + + + align:start position:0% +Okay. And then we're going to say that +the actual number of edges is at least + + align:start position:0% +the actual number of edges is at least + + + align:start position:0% +the actual number of edges is at least +some fraction of that. + + align:start position:0% +some fraction of that. + + + align:start position:0% +some fraction of that. +If sigma 1 of TA were one, this would be + + align:start position:0% +If sigma 1 of TA were one, this would be + + + align:start position:0% +If sigma 1 of TA were one, this would be +a trivial inequality. It's bigger than + + align:start position:0% +a trivial inequality. It's bigger than + + + align:start position:0% +a trivial inequality. It's bigger than +zero. But if sigma 1 is is smaller than + + align:start position:0% +zero. But if sigma 1 is is smaller than + + + align:start position:0% +zero. But if sigma 1 is is smaller than +one, then this is a non-trivial + + align:start position:0% +one, then this is a non-trivial + + + align:start position:0% +one, then this is a non-trivial +inequality. and it says that the number + + align:start position:0% +inequality. and it says that the number + + + align:start position:0% +inequality. and it says that the number +of edges is a certain a definite + + align:start position:0% +of edges is a certain a definite + + + align:start position:0% +of edges is a certain a definite +fraction of what you would see in the + + align:start position:0% +fraction of what you would see in the + + + align:start position:0% +fraction of what you would see in the +random model. + + align:start position:0% +random model. + + + align:start position:0% +random model. +Okay, so let's prove this or at least + + align:start position:0% +Okay, so let's prove this or at least + + + align:start position:0% +Okay, so let's prove this or at least +give a proof sketch. + + align:start position:0% +give a proof sketch. + + + align:start position:0% +give a proof sketch. +So the key point is that we can describe + + align:start position:0% +So the key point is that we can describe + + + align:start position:0% +So the key point is that we can describe +this quantity using this operator TA and + + align:start position:0% +this quantity using this operator TA and + + + align:start position:0% +this quantity using this operator TA and +then it becomes not so surprising that + + align:start position:0% +then it becomes not so surprising that + + + align:start position:0% +then it becomes not so surprising that +the singular value of TA is relevant. + + align:start position:0% +the singular value of TA is relevant. + + + align:start position:0% +the singular value of TA is relevant. +How do you do it? The number of edges + + align:start position:0% +How do you do it? The number of edges + + + align:start position:0% +How do you do it? The number of edges +from S to S complement is the inner + + align:start position:0% +from S to S complement is the inner + + + align:start position:0% +from S to S complement is the inner +product is inner product of TA of the + + align:start position:0% +product is inner product of TA of the + + + align:start position:0% +product is inner product of TA of the +characteristic function of S with the + + align:start position:0% +characteristic function of S with the + + + align:start position:0% +characteristic function of S with the +characteristic function of S complement + + align:start position:0% +characteristic function of S complement + + + align:start position:0% +characteristic function of S complement +and there's a factor of a in front. This + + align:start position:0% +and there's a factor of a in front. This + + + align:start position:0% +and there's a factor of a in front. This +is a normalization. If if TA had been + + align:start position:0% +is a normalization. If if TA had been + + + align:start position:0% +is a normalization. If if TA had been +just TA is an averaging operator, but we + + align:start position:0% +just TA is an averaging operator, but we + + + align:start position:0% +just TA is an averaging operator, but we +didn't really want to average. We wanted + + align:start position:0% +didn't really want to average. We wanted + + + align:start position:0% +didn't really want to average. We wanted +to count edges. So there's an extra + + align:start position:0% +to count edges. So there's an extra + + + align:start position:0% +to count edges. So there's an extra +factor. + + align:start position:0% + + + + align:start position:0% + +Okay. Does this look plausible to + + align:start position:0% +Okay. Does this look plausible to + + + align:start position:0% +Okay. Does this look plausible to +people? Should we write this? + + align:start position:0% +people? Should we write this? + + + align:start position:0% +people? Should we write this? +Let's write this out a little bit. + + align:start position:0% +Let's write this out a little bit. + + + align:start position:0% +Let's write this out a little bit. +So t a1s + + align:start position:0% +So t a1s + + + align:start position:0% +So t a1s +of g + + align:start position:0% +of g + + + align:start position:0% +of g +is 1 / a sum a and a + + align:start position:0% +is 1 / a sum a and a + + + align:start position:0% +is 1 / a sum a and a +of uh + + align:start position:0% + + + + align:start position:0% + +um + + align:start position:0% + + + + align:start position:0% + +s of g + + align:start position:0% +s of g + + + align:start position:0% +s of g +a inverse. + + align:start position:0% +a inverse. + + + align:start position:0% +a inverse. +So that's the definition of the of the + + align:start position:0% +So that's the definition of the of the + + + align:start position:0% +So that's the definition of the of the +convolution. + + align:start position:0% +convolution. + + + align:start position:0% +convolution. +Um + + align:start position:0% + + + + align:start position:0% + +so we we so then when we take this inner + + align:start position:0% +so we we so then when we take this inner + + + align:start position:0% +so we we so then when we take this inner +product we're going to have the um sum g + + align:start position:0% +product we're going to have the um sum g + + + align:start position:0% +product we're going to have the um sum g +and g + + align:start position:0% + + + + align:start position:0% + +1 / a sum a + + align:start position:0% +1 / a sum a + + + align:start position:0% +1 / a sum a +1 s of g a inverse one s complement of + + align:start position:0% + + + + align:start position:0% + +So we will only be counting + + align:start position:0% +So we will only be counting + + + align:start position:0% +So we will only be counting +uh we'll be counting G's that are in S + + align:start position:0% +uh we'll be counting G's that are in S + + + align:start position:0% +uh we'll be counting G's that are in S +complement but GA inverse is an S and + + align:start position:0% +complement but GA inverse is an S and + + + align:start position:0% +complement but GA inverse is an S and +that's an edge that starts in S and goes + + align:start position:0% +that's an edge that starts in S and goes + + + align:start position:0% +that's an edge that starts in S and goes +to S complnt. + + align:start position:0% + + + + align:start position:0% + +So S S complement + + align:start position:0% +So S S complement + + + align:start position:0% +So S S complement +over here we have G. Over here we have + + align:start position:0% +over here we have G. Over here we have + + + align:start position:0% +over here we have G. Over here we have +GA inverse and those are connected by an + + align:start position:0% +GA inverse and those are connected by an + + + align:start position:0% +GA inverse and those are connected by an +edge. That's the thing that we're + + align:start position:0% +edge. That's the thing that we're + + + align:start position:0% +edge. That's the thing that we're +counting. + + align:start position:0% + + + + align:start position:0% + +Okay, this double sum here means we're + + align:start position:0% +Okay, this double sum here means we're + + + align:start position:0% +Okay, this double sum here means we're +counting all of the going through all + + align:start position:0% +counting all of the going through all + + + align:start position:0% +counting all of the going through all +the edges, but we're only counting an + + align:start position:0% +the edges, but we're only counting an + + + align:start position:0% +the edges, but we're only counting an +edge if it goes from S to S complement. + + align:start position:0% +edge if it goes from S to S complement. + + + align:start position:0% +edge if it goes from S to S complement. +And we have this, which we didn't really + + align:start position:0% +And we have this, which we didn't really + + + align:start position:0% +And we have this, which we didn't really +want, which is why we multiplied by this + + align:start position:0% +want, which is why we multiplied by this + + + align:start position:0% +want, which is why we multiplied by this +over here. + + align:start position:0% + + + + align:start position:0% + +Okay, good. + + align:start position:0% +Okay, good. + + + align:start position:0% +Okay, good. +Okay, so now remember that this operator + + align:start position:0% +Okay, so now remember that this operator + + + align:start position:0% +Okay, so now remember that this operator +uh sort of splits we it takes the + + align:start position:0% +uh sort of splits we it takes the + + + align:start position:0% +uh sort of splits we it takes the +constant functions to the constant + + align:start position:0% +constant functions to the constant + + + align:start position:0% +constant functions to the constant +functions and it takes the mean zero + + align:start position:0% +functions and it takes the mean zero + + + align:start position:0% +functions and it takes the mean zero +functions to the mean zero functions. So + + align:start position:0% +functions to the mean zero functions. So + + + align:start position:0% +functions to the mean zero functions. So +we should split everybody in sight into + + align:start position:0% +we should split everybody in sight into + + + align:start position:0% +we should split everybody in sight into +a constant part and a mean zero part. + + align:start position:0% + + + + align:start position:0% + +So we split + + align:start position:0% +So we split + + + align:start position:0% +So we split +1 s is s over g that's the constant part + + align:start position:0% +1 s is s over g that's the constant part + + + align:start position:0% +1 s is s over g that's the constant part +plus 1 s minus s over g. So this I'll + + align:start position:0% +plus 1 s minus s over g. So this I'll + + + align:start position:0% +plus 1 s minus s over g. So this I'll +call it 1 s high and it lives in l2 g0. + + align:start position:0% +call it 1 s high and it lives in l2 g0. + + + align:start position:0% +call it 1 s high and it lives in l2 g0. +Okay. Do the same thing for s + + align:start position:0% +Okay. Do the same thing for s + + + align:start position:0% +Okay. Do the same thing for s +complement. So now the number of edges + + align:start position:0% +complement. So now the number of edges + + + align:start position:0% +complement. So now the number of edges +from S to S complement + + align:start position:0% +from S to S complement + + + align:start position:0% +from S to S complement +that is A times + + align:start position:0% +that is A times + + + align:start position:0% +that is A times +um okay we'll have TA of the constant + + align:start position:0% +um okay we'll have TA of the constant + + + align:start position:0% +um okay we'll have TA of the constant +parts so that's SG s complement G + + align:start position:0% +parts so that's SG s complement G + + + align:start position:0% +parts so that's SG s complement G +plus A times the high frequency high + + align:start position:0% +plus A times the high frequency high + + + align:start position:0% +plus A times the high frequency high +frequency parts uh the non the mean zero + + align:start position:0% +frequency parts uh the non the mean zero + + + align:start position:0% +frequency parts uh the non the mean zero +parts um TA of 1s high + + align:start position:0% +parts um TA of 1s high + + + align:start position:0% +parts um TA of 1s high +one as complement. + + align:start position:0% + + + + align:start position:0% + +Okay. So let's call this zero and this + + align:start position:0% +Okay. So let's call this zero and this + + + align:start position:0% +Okay. So let's call this zero and this +is the high part or the let's call this + + align:start position:0% +is the high part or the let's call this + + + align:start position:0% +is the high part or the let's call this +the constant part and this is the high + + align:start position:0% +the constant part and this is the high + + + align:start position:0% +the constant part and this is the high +part. + + align:start position:0% +part. + + + align:start position:0% +part. +Okay. So the rest of it is just a + + align:start position:0% +Okay. So the rest of it is just a + + + align:start position:0% +Okay. So the rest of it is just a +computation and I won't do the algebra + + align:start position:0% +computation and I won't do the algebra + + + align:start position:0% +computation and I won't do the algebra +carefully but if you do the constant + + align:start position:0% +carefully but if you do the constant + + + align:start position:0% +carefully but if you do the constant +part you get this as SS complement over + + align:start position:0% +part you get this as SS complement over + + + align:start position:0% +part you get this as SS complement over +G. The constant part exactly tracks what + + align:start position:0% +G. The constant part exactly tracks what + + + align:start position:0% +G. The constant part exactly tracks what +would happen if all the edges were + + align:start position:0% +would happen if all the edges were + + + align:start position:0% +would happen if all the edges were +random. Okay. And then for the high part + + align:start position:0% +random. Okay. And then for the high part + + + align:start position:0% +random. Okay. And then for the high part +of course we won't compute it exactly + + align:start position:0% +of course we won't compute it exactly + + + align:start position:0% +of course we won't compute it exactly +because we have to know what the + + align:start position:0% +because we have to know what the + + + align:start position:0% +because we have to know what the +operator TA is. But we can bound it by + + align:start position:0% +operator TA is. But we can bound it by + + + align:start position:0% +operator TA is. But we can bound it by +the um by the norm of TA sigma 1 of TA + + align:start position:0% +the um by the norm of TA sigma 1 of TA + + + align:start position:0% +the um by the norm of TA sigma 1 of TA +times 1 S high in L2 + + align:start position:0% +times 1 S high in L2 + + + align:start position:0% +times 1 S high in L2 +times 1 S complement high in L2. + + align:start position:0% + + + + align:start position:0% + +Okay. And then those things are + + align:start position:0% +Okay. And then those things are + + + align:start position:0% +Okay. And then those things are +straightforward to compute those L2 + + align:start position:0% +straightforward to compute those L2 + + + align:start position:0% +straightforward to compute those L2 +norms. And if you work if you compute + + align:start position:0% +norms. And if you work if you compute + + + align:start position:0% +norms. And if you work if you compute +them you get that this is a this is I'll + + align:start position:0% +them you get that this is a this is I'll + + + align:start position:0% +them you get that this is a this is I'll +put the sigma one out front. + + align:start position:0% +put the sigma one out front. + + + align:start position:0% +put the sigma one out front. +And then it's the same thing a s S + + align:start position:0% +And then it's the same thing a s S + + + align:start position:0% +And then it's the same thing a s S +complement over G. + + align:start position:0% +complement over G. + + + align:start position:0% +complement over G. +Okay. So the true answer is the constant + + align:start position:0% +Okay. So the true answer is the constant + + + align:start position:0% +Okay. So the true answer is the constant +term plus the high term which is like an + + align:start position:0% +term plus the high term which is like an + + + align:start position:0% +term plus the high term which is like an +error term and whose size is at most + + align:start position:0% +error term and whose size is at most + + + align:start position:0% +error term and whose size is at most +this. And if sigma 1 is strictly less + + align:start position:0% +this. And if sigma 1 is strictly less + + + align:start position:0% +this. And if sigma 1 is strictly less +than one then the error term is strictly + + align:start position:0% +than one then the error term is strictly + + + align:start position:0% +than one then the error term is strictly +smaller than the constant term. So + + align:start position:0% +smaller than the constant term. So + + + align:start position:0% +smaller than the constant term. So +something will be left over and that's + + align:start position:0% +something will be left over and that's + + + align:start position:0% +something will be left over and that's +the inequality. + + align:start position:0% + + + + align:start position:0% + +Okay, so let me make a little remark. + + align:start position:0% +Okay, so let me make a little remark. + + + align:start position:0% +Okay, so let me make a little remark. +Um, if S is smaller than G over two, + + align:start position:0% +Um, if S is smaller than G over two, + + + align:start position:0% +Um, if S is smaller than G over two, +then S complement is bigger than G + + align:start position:0% +then S complement is bigger than G + + + align:start position:0% +then S complement is bigger than G +over2. So this is more or less without + + align:start position:0% +over2. So this is more or less without + + + align:start position:0% +over2. So this is more or less without +loss of generality. You know, if you + + align:start position:0% +loss of generality. You know, if you + + + align:start position:0% +loss of generality. You know, if you +switch the roles of S and S complement, + + align:start position:0% +switch the roles of S and S complement, + + + align:start position:0% +switch the roles of S and S complement, +but it means S complement is at least G + + align:start position:0% +but it means S complement is at least G + + + align:start position:0% +but it means S complement is at least G +over2, which means that this whole + + align:start position:0% +over2, which means that this whole + + + align:start position:0% +over2, which means that this whole +fraction has order of one. So then we + + align:start position:0% +fraction has order of one. So then we + + + align:start position:0% +fraction has order of one. So then we +get that the number of edges from S to S + + align:start position:0% +get that the number of edges from S to S + + + align:start position:0% +get that the number of edges from S to S +complement is at least half sigma 1 of + + align:start position:0% +complement is at least half sigma 1 of + + + align:start position:0% +complement is at least half sigma 1 of +TA + + align:start position:0% +TA + + + align:start position:0% +TA +A time S. So it's at least uh a definite + + align:start position:0% +A time S. So it's at least uh a definite + + + align:start position:0% +A time S. So it's at least uh a definite +fraction of all of the possible edges + + align:start position:0% +fraction of all of the possible edges + + + align:start position:0% +fraction of all of the possible edges +that it could be living leaving us. + + align:start position:0% +that it could be living leaving us. + + + align:start position:0% +that it could be living leaving us. +Okay. So this property here is called + + align:start position:0% +Okay. So this property here is called + + + align:start position:0% +Okay. So this property here is called +being an expander graph + + align:start position:0% + + + + align:start position:0% + +because if you take a set that's less + + align:start position:0% +because if you take a set that's less + + + align:start position:0% +because if you take a set that's less +than half of the graph and then you add + + align:start position:0% +than half of the graph and then you add + + + align:start position:0% +than half of the graph and then you add +to it all of the edges that are leaving + + align:start position:0% +to it all of the edges that are leaving + + + align:start position:0% +to it all of the edges that are leaving +it then it will get significantly + + align:start position:0% +it then it will get significantly + + + align:start position:0% +it then it will get significantly +bigger. It will expand. So it's called + + align:start position:0% +bigger. It will expand. So it's called + + + align:start position:0% +bigger. It will expand. So it's called +an expander graph. + + align:start position:0% +an expander graph. + + + align:start position:0% +an expander graph. +Okay. + + align:start position:0% +Okay. + + + align:start position:0% +Okay. +Okay. Cool. + + align:start position:0% +Okay. Cool. + + + align:start position:0% +Okay. Cool. +Um so so this proposition shows + + align:start position:0% + + + + align:start position:0% + +that if this sigma one is strictly less + + align:start position:0% +that if this sigma one is strictly less + + + align:start position:0% +that if this sigma one is strictly less +than one it's something like in Selber's + + align:start position:0% +than one it's something like in Selber's + + + align:start position:0% +than one it's something like in Selber's +theorem then the edges in the graph + + align:start position:0% +theorem then the edges in the graph + + + align:start position:0% +theorem then the edges in the graph +behave in this way that it's an expanded + + align:start position:0% +behave in this way that it's an expanded + + + align:start position:0% +behave in this way that it's an expanded +graph. + + align:start position:0% +graph. + + + align:start position:0% +graph. +Okay, cool. + + align:start position:0% + + + + align:start position:0% + +Okay, now so Selberg did not state his + + align:start position:0% +Okay, now so Selberg did not state his + + + align:start position:0% +Okay, now so Selberg did not state his +theorem in this way. So this is slightly + + align:start position:0% +theorem in this way. So this is slightly + + + align:start position:0% +theorem in this way. So this is slightly +ahistorical, but Selberg's theorem plus + + align:start position:0% +ahistorical, but Selberg's theorem plus + + + align:start position:0% +ahistorical, but Selberg's theorem plus +things that are not very difficult in + + align:start position:0% +things that are not very difficult in + + + align:start position:0% +things that are not very difficult in +hindsight show that this kaly graph of + + align:start position:0% +hindsight show that this kaly graph of + + + align:start position:0% +hindsight show that this kaly graph of +SL2FP is an expander graph and it is in + + align:start position:0% +SL2FP is an expander graph and it is in + + + align:start position:0% +SL2FP is an expander graph and it is in +a sense the first Zelberg didn't quite + + align:start position:0% +a sense the first Zelberg didn't quite + + + align:start position:0% +a sense the first Zelberg didn't quite +say this but in a sense this was the + + align:start position:0% +say this but in a sense this was the + + + align:start position:0% +say this but in a sense this was the +first proof that any graph was an + + align:start position:0% +first proof that any graph was an + + + align:start position:0% +first proof that any graph was an +expander graph. Um, expander graphs were + + align:start position:0% +expander graph. Um, expander graphs were + + + align:start position:0% +expander graph. Um, expander graphs were +officially defined in 1970 by Pinsker + + align:start position:0% +officially defined in 1970 by Pinsker + + + align:start position:0% +officially defined in 1970 by Pinsker +and something pretty close by Koma Garf + + align:start position:0% +and something pretty close by Koma Garf + + + align:start position:0% +and something pretty close by Koma Garf +and Bars in the 60s and all of those + + align:start position:0% +and Bars in the 60s and all of those + + + align:start position:0% +and Bars in the 60s and all of those +people realized that um random graphs + + align:start position:0% +people realized that um random graphs + + + align:start position:0% +people realized that um random graphs +were expander graphs. + + align:start position:0% + + + + align:start position:0% + +Um, + + align:start position:0% +Um, + + + align:start position:0% +Um, +yeah. So I maybe many people have seen + + align:start position:0% +yeah. So I maybe many people have seen + + + align:start position:0% +yeah. So I maybe many people have seen +but it's really a remarkable thing. So, + + align:start position:0% +but it's really a remarkable thing. So, + + + align:start position:0% +but it's really a remarkable thing. So, +so just for comparison, like a simple + + align:start position:0% +so just for comparison, like a simple + + + align:start position:0% +so just for comparison, like a simple +graph that we might think of that we can + + align:start position:0% +graph that we might think of that we can + + + align:start position:0% +graph that we might think of that we can +easily visualize would be like a like an + + align:start position:0% +easily visualize would be like a like an + + + align:start position:0% +easily visualize would be like a like an +n byn grid and that kind of graph is not + + align:start position:0% +n byn grid and that kind of graph is not + + + align:start position:0% +n byn grid and that kind of graph is not +an expander at all. So an n byn grid has + + align:start position:0% +an expander at all. So an n byn grid has + + + align:start position:0% +an expander at all. So an n byn grid has +n squared vertices but you can cut it in + + align:start position:0% +n squared vertices but you can cut it in + + + align:start position:0% +n squared vertices but you can cut it in +half with a vertical line and you only + + align:start position:0% +half with a vertical line and you only + + + align:start position:0% +half with a vertical line and you only +cut n edges. So the number of edges so s + + align:start position:0% +cut n edges. So the number of edges so s + + + align:start position:0% +cut n edges. So the number of edges so s +and s complement are each about half of + + align:start position:0% +and s complement are each about half of + + + align:start position:0% +and s complement are each about half of +the graph. The number of edges between + + align:start position:0% +the graph. The number of edges between + + + align:start position:0% +the graph. The number of edges between +them is is much smaller than s. Um so + + align:start position:0% +them is is much smaller than s. Um so + + + align:start position:0% +them is is much smaller than s. Um so +these are very large graphs but the + + align:start position:0% +these are very large graphs but the + + + align:start position:0% +these are very large graphs but the +number of edges it takes to cut it in + + align:start position:0% +number of edges it takes to cut it in + + + align:start position:0% +number of edges it takes to cut it in +half is comparable to all of the edges + + align:start position:0% +half is comparable to all of the edges + + + align:start position:0% +half is comparable to all of the edges +and um it most graphs are like that but + + align:start position:0% +and um it most graphs are like that but + + + align:start position:0% +and um it most graphs are like that but +before people realized it it was + + align:start position:0% +before people realized it it was + + + align:start position:0% +before people realized it it was +surprising and counterintuitive that any + + align:start position:0% +surprising and counterintuitive that any + + + align:start position:0% +surprising and counterintuitive that any +graphs were like that and it's very + + align:start position:0% +graphs were like that and it's very + + + align:start position:0% +graphs were like that and it's very +significant fact in many domains of math + + align:start position:0% +significant fact in many domains of math + + + align:start position:0% +significant fact in many domains of math +and science. + + align:start position:0% + + + + align:start position:0% + +Okay. + + align:start position:0% +Okay. + + + align:start position:0% +Okay. +Uh okay, let me pause there and + + align:start position:0% +Uh okay, let me pause there and + + + align:start position:0% +Uh okay, let me pause there and +questions about about Selberg's theorem + + align:start position:0% +questions about about Selberg's theorem + + + align:start position:0% +questions about about Selberg's theorem +and this setup mixing and expansion. + + align:start position:0% + + + + align:start position:0% + +>> The point of a generators is just so + + align:start position:0% +>> The point of a generators is just so + + + align:start position:0% +>> The point of a generators is just so +that it's connected. + + align:start position:0% +that it's connected. + + + align:start position:0% +that it's connected. +>> Yes, that's right. So um so the question + + align:start position:0% +>> Yes, that's right. So um so the question + + + align:start position:0% +>> Yes, that's right. So um so the question +is uh is what what is the point of a + + align:start position:0% +is uh is what what is the point of a + + + align:start position:0% +is uh is what what is the point of a +being generators? + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +So if a did not generate the group then + + align:start position:0% +So if a did not generate the group then + + + align:start position:0% +So if a did not generate the group then +this graph would be disconnected and + + align:start position:0% +this graph would be disconnected and + + + align:start position:0% +this graph would be disconnected and +then it wouldn't mix at all. Um so make + + align:start position:0% +then it wouldn't mix at all. Um so make + + + align:start position:0% +then it wouldn't mix at all. Um so make +a remark + + align:start position:0% +a remark + + + align:start position:0% +a remark +suppose that A is in a finite group and + + align:start position:0% +suppose that A is in a finite group and + + + align:start position:0% +suppose that A is in a finite group and +that H + + align:start position:0% +that H + + + align:start position:0% +that H +the so the the subgroup + + align:start position:0% +the so the the subgroup + + + align:start position:0% +the so the the subgroup +generated by A is H which is a proper + + align:start position:0% +generated by A is H which is a proper + + + align:start position:0% +generated by A is H which is a proper +subgroup. + + align:start position:0% + + + + align:start position:0% + +Okay. So then if we take TA and we apply + + align:start position:0% +Okay. So then if we take TA and we apply + + + align:start position:0% +Okay. So then if we take TA and we apply +it to the characteristic function of + + align:start position:0% +it to the characteristic function of + + + align:start position:0% +it to the characteristic function of +this subgroup since all of these guys + + align:start position:0% +this subgroup since all of these guys + + + align:start position:0% +this subgroup since all of these guys +are in the subgroup we would just stay + + align:start position:0% +are in the subgroup we would just stay + + + align:start position:0% +are in the subgroup we would just stay +in the subgroup. So this would be 1 H. + + align:start position:0% + + + + align:start position:0% + +Okay. And um and that implies with a + + align:start position:0% +Okay. And um and that implies with a + + + align:start position:0% +Okay. And um and that implies with a +teeny bit of work that sigma 1 of TA + + align:start position:0% +teeny bit of work that sigma 1 of TA + + + align:start position:0% +teeny bit of work that sigma 1 of TA +would be one. + + align:start position:0% +would be one. + + + align:start position:0% +would be one. +Right? So, okay, one thing we could see + + align:start position:0% +Right? So, okay, one thing we could see + + + align:start position:0% +Right? So, okay, one thing we could see +is that no matter how many times we + + align:start position:0% +is that no matter how many times we + + + align:start position:0% +is that no matter how many times we +repeat this operation, we will never mix + + align:start position:0% +repeat this operation, we will never mix + + + align:start position:0% +repeat this operation, we will never mix +over the whole group because we'll never + + align:start position:0% +over the whole group because we'll never + + + align:start position:0% +over the whole group because we'll never +get out of H. And so, based on what + + align:start position:0% +get out of H. And so, based on what + + + align:start position:0% +get out of H. And so, based on what +we've seen before, um, this should be + + align:start position:0% +we've seen before, um, this should be + + + align:start position:0% +we've seen before, um, this should be +one. + + align:start position:0% +one. + + + align:start position:0% +one. +Yeah. + + align:start position:0% +Yeah. + + + align:start position:0% +Yeah. +>> Just make a big does it just make the + + align:start position:0% +>> Just make a big does it just make the + + + align:start position:0% +>> Just make a big does it just make the +graph more + + align:start position:0% +graph more + + + align:start position:0% +graph more +likely to be an expander? + + align:start position:0% +likely to be an expander? + + + align:start position:0% +likely to be an expander? +>> Yeah. So, the question is, if we make a + + align:start position:0% +>> Yeah. So, the question is, if we make a + + + align:start position:0% +>> Yeah. So, the question is, if we make a +big, is the graph more likely to be an + + align:start position:0% +big, is the graph more likely to be an + + + align:start position:0% +big, is the graph more likely to be an +expander? Um + + align:start position:0% +expander? Um + + + align:start position:0% +expander? Um +perhaps if we so we could we could take + + align:start position:0% +perhaps if we so we could we could take + + + align:start position:0% +perhaps if we so we could we could take +a big and then it would um so we're so + + align:start position:0% +a big and then it would um so we're so + + + align:start position:0% +a big and then it would um so we're so +we're allowed to take a big and um we + + align:start position:0% +we're allowed to take a big and um we + + + align:start position:0% +we're allowed to take a big and um we +will talk in a little bit about what + + align:start position:0% +will talk in a little bit about what + + + align:start position:0% +will talk in a little bit about what +what we can say if we just know that a + + align:start position:0% +what we can say if we just know that a + + + align:start position:0% +what we can say if we just know that a +is big what does that tell us about + + align:start position:0% +is big what does that tell us about + + + align:start position:0% +is big what does that tell us about +sigma of ta we'll we'll talk about that + + align:start position:0% +sigma of ta we'll we'll talk about that + + + align:start position:0% +sigma of ta we'll we'll talk about that +right + + align:start position:0% +right + + + align:start position:0% +right +okay so another remark I wanted to make + + align:start position:0% +okay so another remark I wanted to make + + + align:start position:0% +okay so another remark I wanted to make +is that the first proof of this theorem + + align:start position:0% +is that the first proof of this theorem + + + align:start position:0% +is that the first proof of this theorem +was very difficult so the first proof + + align:start position:0% +was very difficult so the first proof + + + align:start position:0% +was very difficult so the first proof +depended on. So it had some interesting + + align:start position:0% +depended on. So it had some interesting + + + align:start position:0% +depended on. So it had some interesting +analysis related to hyperbolic geometry + + align:start position:0% +analysis related to hyperbolic geometry + + + align:start position:0% +analysis related to hyperbolic geometry +but then it depended on the remon + + align:start position:0% +but then it depended on the remon + + + align:start position:0% +but then it depended on the remon +hypothesis for curves over finite + + align:start position:0% +hypothesis for curves over finite + + + align:start position:0% +hypothesis for curves over finite +fields. + + align:start position:0% + + + + align:start position:0% + +So that's a you know a beautiful and + + align:start position:0% +So that's a you know a beautiful and + + + align:start position:0% +So that's a you know a beautiful and +important theorem but if you wanted to + + align:start position:0% +important theorem but if you wanted to + + + align:start position:0% +important theorem but if you wanted to +include the whole proof of that then the + + align:start position:0% +include the whole proof of that then the + + + align:start position:0% +include the whole proof of that then the +proof of this theorem is effectively + + align:start position:0% +proof of this theorem is effectively + + + align:start position:0% +proof of this theorem is effectively +several hundred pages long and has a lot + + align:start position:0% +several hundred pages long and has a lot + + + align:start position:0% +several hundred pages long and has a lot +of algebraic geometry. Um and in around + + align:start position:0% +of algebraic geometry. Um and in around + + + align:start position:0% +of algebraic geometry. Um and in around +the early 1990s, Sarnac and Shuer gave a + + align:start position:0% +the early 1990s, Sarnac and Shuer gave a + + + align:start position:0% +the early 1990s, Sarnac and Shuer gave a +much simpler proof. + + align:start position:0% + + + + align:start position:0% + +Uh which is the proof that we'll talk + + align:start position:0% +Uh which is the proof that we'll talk + + + align:start position:0% +Uh which is the proof that we'll talk +about. + + align:start position:0% + + + + align:start position:0% + +Okay. + + align:start position:0% + + + + align:start position:0% + +Okay. Okay. So in the rest of the class + + align:start position:0% +Okay. Okay. So in the rest of the class + + + align:start position:0% +Okay. Okay. So in the rest of the class +I will start to describe the uh proof by + + align:start position:0% +I will start to describe the uh proof by + + + align:start position:0% +I will start to describe the uh proof by +Sarn and and Shuer um uh and and + + align:start position:0% +Sarn and and Shuer um uh and and + + + align:start position:0% +Sarn and and Shuer um uh and and +introduce the first the first key idea. + + align:start position:0% + + + + align:start position:0% + +All right. + + align:start position:0% + + + + align:start position:0% + +Okay. Um + + align:start position:0% + + + + align:start position:0% + +so first idea + + align:start position:0% +so first idea + + + align:start position:0% +so first idea +this idea has to do with the + + align:start position:0% +this idea has to do with the + + + align:start position:0% +this idea has to do with the +representation theory + + align:start position:0% +representation theory + + + align:start position:0% +representation theory +of the group SL2FP + + align:start position:0% + + + + align:start position:0% + +it's a proposition + + align:start position:0% + + + + align:start position:0% + +okay so if we have a representation so a + + align:start position:0% +okay so if we have a representation so a + + + align:start position:0% +okay so if we have a representation so a +representation is a group homorphism + + align:start position:0% +representation is a group homorphism + + + align:start position:0% +representation is a group homorphism +to uh this is a unitary representation + + align:start position:0% +to uh this is a unitary representation + + + align:start position:0% +to uh this is a unitary representation +so to the unitary group in D dimensions. + + align:start position:0% +so to the unitary group in D dimensions. + + + align:start position:0% +so to the unitary group in D dimensions. +So this is a representation + + align:start position:0% +So this is a representation + + + align:start position:0% +So this is a representation +need a group homorphism + + align:start position:0% + + + + align:start position:0% + +um and okay and let me so there there's + + align:start position:0% +um and okay and let me so there there's + + + align:start position:0% +um and okay and let me so there there's +the trivial representation where + + align:start position:0% +the trivial representation where + + + align:start position:0% +the trivial representation where +everything goes to the identity but let + + align:start position:0% +everything goes to the identity but let + + + align:start position:0% +everything goes to the identity but let +me say it is a non-trivial + + align:start position:0% +me say it is a non-trivial + + + align:start position:0% +me say it is a non-trivial +representation + + align:start position:0% +representation + + + align:start position:0% +representation +um then actually d needs to be quite big + + align:start position:0% +um then actually d needs to be quite big + + + align:start position:0% +um then actually d needs to be quite big +d is at least p + 1 over + + align:start position:0% + + + + align:start position:0% + +Okay, + + align:start position:0% +Okay, + + + align:start position:0% +Okay, +so before we prove this theorem, let's + + align:start position:0% +so before we prove this theorem, let's + + + align:start position:0% +so before we prove this theorem, let's +try to put it in context by trying to + + align:start position:0% +try to put it in context by trying to + + + align:start position:0% +try to put it in context by trying to +think about group representations. + + align:start position:0% +think about group representations. + + + align:start position:0% +think about group representations. +Um, where would we find a group + + align:start position:0% +Um, where would we find a group + + + align:start position:0% +Um, where would we find a group +representation? + + align:start position:0% +representation? + + + align:start position:0% +representation? +Okay, well SL2FP acts on itself. So it + + align:start position:0% +Okay, well SL2FP acts on itself. So it + + + align:start position:0% +Okay, well SL2FP acts on itself. So it +acts on the space that we started with + + align:start position:0% +acts on the space that we started with + + + align:start position:0% +acts on the space that we started with +L2 of G. So, so any so any group G + + align:start position:0% +L2 of G. So, so any so any group G + + + align:start position:0% +L2 of G. So, so any so any group G +acts on L2 G by the action that we sort + + align:start position:0% +acts on L2 G by the action that we sort + + + align:start position:0% +acts on L2 G by the action that we sort +of wrote down. You take a function and + + align:start position:0% +of wrote down. You take a function and + + + align:start position:0% +of wrote down. You take a function and +you like shift the space under it. + + align:start position:0% +you like shift the space under it. + + + align:start position:0% +you like shift the space under it. +Okay, that action is not trivial. So the + + align:start position:0% +Okay, that action is not trivial. So the + + + align:start position:0% +Okay, that action is not trivial. So the +only only the constant functions are + + align:start position:0% +only only the constant functions are + + + align:start position:0% +only only the constant functions are +fixed. So that's a non-trivial action. + + align:start position:0% +fixed. So that's a non-trivial action. + + + align:start position:0% +fixed. So that's a non-trivial action. +And the dimension of this space is the + + align:start position:0% +And the dimension of this space is the + + + align:start position:0% +And the dimension of this space is the +cardality of G. So for this group that + + align:start position:0% +cardality of G. So for this group that + + + align:start position:0% +cardality of G. So for this group that +would be about P cubed. + + align:start position:0% +would be about P cubed. + + + align:start position:0% +would be about P cubed. +So cardality of SL2 + + align:start position:0% +So cardality of SL2 + + + align:start position:0% +So cardality of SL2 +FP. + + align:start position:0% + + + + align:start position:0% + +Okay. Um + + align:start position:0% +Okay. Um + + + align:start position:0% +Okay. Um +what else? Well, if you have a subgroup + + align:start position:0% +what else? Well, if you have a subgroup + + + align:start position:0% +what else? Well, if you have a subgroup +of G, + + align:start position:0% +of G, + + + align:start position:0% +of G, +H is a subgroup + + align:start position:0% +H is a subgroup + + + align:start position:0% +H is a subgroup +of G. Then um G acts + + align:start position:0% +of G. Then um G acts + + + align:start position:0% +of G. Then um G acts +on G mod H and so it acts + + align:start position:0% +on G mod H and so it acts + + + align:start position:0% +on G mod H and so it acts +acts on this as a set and so it acts on + + align:start position:0% +acts on this as a set and so it acts on + + + align:start position:0% +acts on this as a set and so it acts on +L2 of G mod H by a unitary + + align:start position:0% +L2 of G mod H by a unitary + + + align:start position:0% +L2 of G mod H by a unitary +representation and so the dimension + + align:start position:0% +representation and so the dimension + + + align:start position:0% +representation and so the dimension +of L2 of GH + + align:start position:0% +of L2 of GH + + + align:start position:0% +of L2 of GH +is the cardality of G mod which is the + + align:start position:0% +is the cardality of G mod which is the + + + align:start position:0% +is the cardality of G mod which is the +cardality of G divided by the cardality + + align:start position:0% +cardality of G divided by the cardality + + + align:start position:0% +cardality of G divided by the cardality +of H. + + align:start position:0% +of H. + + + align:start position:0% +of H. +Okay, so let's think of some subgroups + + align:start position:0% +Okay, so let's think of some subgroups + + + align:start position:0% +Okay, so let's think of some subgroups +of SL2FP. + + align:start position:0% + + + + align:start position:0% + +Think of there's the diagonal subgroup + + align:start position:0% +Think of there's the diagonal subgroup + + + align:start position:0% +Think of there's the diagonal subgroup +looks like this. + + align:start position:0% + + + + align:start position:0% + +The size of the diagonal subgroup is + + align:start position:0% +The size of the diagonal subgroup is + + + align:start position:0% +The size of the diagonal subgroup is +around P. There's the unipotent subgroup + + align:start position:0% +around P. There's the unipotent subgroup + + + align:start position:0% +around P. There's the unipotent subgroup +looks like this. Size of the unipotent + + align:start position:0% +looks like this. Size of the unipotent + + + align:start position:0% +looks like this. Size of the unipotent +subgroup is P. + + align:start position:0% +subgroup is P. + + + align:start position:0% +subgroup is P. +And you could sort of mix these + + align:start position:0% +And you could sort of mix these + + + align:start position:0% +And you could sort of mix these +together. So there's the upper + + align:start position:0% +together. So there's the upper + + + align:start position:0% +together. So there's the upper +triangular subgroup. Uh but we already + + align:start position:0% +triangular subgroup. Uh but we already + + + align:start position:0% +triangular subgroup. Uh but we already +used the letter U. So I'm going to call + + align:start position:0% +used the letter U. So I'm going to call + + + align:start position:0% +used the letter U. So I'm going to call +this B for Burell. Uh so I'll write it A + + align:start position:0% +this B for Burell. Uh so I'll write it A + + + align:start position:0% +this B for Burell. Uh so I'll write it A +A inverse T. + + align:start position:0% +A inverse T. + + + align:start position:0% +A inverse T. +That's a subgroup. And the size of the + + align:start position:0% +That's a subgroup. And the size of the + + + align:start position:0% +That's a subgroup. And the size of the +upper triangle subgroup is around P^ + + align:start position:0% +upper triangle subgroup is around P^ + + + align:start position:0% +upper triangle subgroup is around P^ +squ. So that's the biggest one that we + + align:start position:0% +squ. So that's the biggest one that we + + + align:start position:0% +squ. So that's the biggest one that we +have come up with here. And if you plug + + align:start position:0% +have come up with here. And if you plug + + + align:start position:0% +have come up with here. And if you plug +this in here, uh so if you take SL2FP, + + align:start position:0% + + + + align:start position:0% + +that's around P. And so this is uh the + + align:start position:0% +that's around P. And so this is uh the + + + align:start position:0% +that's around P. And so this is uh the +right order of magnitude. + + align:start position:0% + + + + align:start position:0% + +Okay. And this is an interesting fact + + align:start position:0% +Okay. And this is an interesting fact + + + align:start position:0% +Okay. And this is an interesting fact +about this group which is extremely + + align:start position:0% +about this group which is extremely + + + align:start position:0% +about this group which is extremely +different from a billion groups. So for + + align:start position:0% +different from a billion groups. So for + + + align:start position:0% +different from a billion groups. So for +for an aelion group uh every irreducible + + align:start position:0% +for an aelion group uh every irreducible + + + align:start position:0% +for an aelion group uh every irreducible +representation is onedimensional. So + + align:start position:0% +representation is onedimensional. So + + + align:start position:0% +representation is onedimensional. So +there are lots and lots of + + align:start position:0% +there are lots and lots of + + + align:start position:0% +there are lots and lots of +representations where D is one. But for + + align:start position:0% +representations where D is one. But for + + + align:start position:0% +representations where D is one. But for +SL2FP life is very different. All of + + align:start position:0% +SL2FP life is very different. All of + + + align:start position:0% +SL2FP life is very different. All of +them have very large dimension. + + align:start position:0% +them have very large dimension. + + + align:start position:0% +them have very large dimension. +Okay. + + align:start position:0% +Okay. + + + align:start position:0% +Okay. +So let's prove this theorem. + + align:start position:0% + + + + align:start position:0% + +Uh so I had heard about this theorem + + align:start position:0% +Uh so I had heard about this theorem + + + align:start position:0% +Uh so I had heard about this theorem +years ago and I always assumed that to + + align:start position:0% +years ago and I always assumed that to + + + align:start position:0% +years ago and I always assumed that to +prove this theorem one had to study a + + align:start position:0% +prove this theorem one had to study a + + + align:start position:0% +prove this theorem one had to study a +lot of representation theory and I was a + + align:start position:0% +lot of representation theory and I was a + + + align:start position:0% +lot of representation theory and I was a +little intimidated by it. Uh but then I + + align:start position:0% +little intimidated by it. Uh but then I + + + align:start position:0% +little intimidated by it. Uh but then I +read the proof as I was getting ready to + + align:start position:0% +read the proof as I was getting ready to + + + align:start position:0% +read the proof as I was getting ready to +teach this class and actually it it + + align:start position:0% +teach this class and actually it it + + + align:start position:0% +teach this class and actually it it +doesn't require anything that's outside + + align:start position:0% +doesn't require anything that's outside + + + align:start position:0% +doesn't require anything that's outside +of uh you know a good a good + + align:start position:0% +of uh you know a good a good + + + align:start position:0% +of uh you know a good a good +undergraduate algebra curriculum + + align:start position:0% +undergraduate algebra curriculum + + + align:start position:0% +undergraduate algebra curriculum +and it's quite elegant. + + align:start position:0% + + + + align:start position:0% + +All right. So here's the proof. Um, + + align:start position:0% +All right. So here's the proof. Um, + + + align:start position:0% +All right. So here's the proof. Um, +so we're going to focus on this matrix + + align:start position:0% +so we're going to focus on this matrix + + + align:start position:0% +so we're going to focus on this matrix +for a little while and try to figure out + + align:start position:0% +for a little while and try to figure out + + + align:start position:0% +for a little while and try to figure out +what the representation does with this + + align:start position:0% +what the representation does with this + + + align:start position:0% +what the representation does with this +matrix. + + align:start position:0% +matrix. + + + align:start position:0% +matrix. +So let's suppose for now + + align:start position:0% +So let's suppose for now + + + align:start position:0% +So let's suppose for now +that row of this matrix is not just the + + align:start position:0% +that row of this matrix is not just the + + + align:start position:0% +that row of this matrix is not just the +identity. + + align:start position:0% + + + + align:start position:0% + +Um, + + align:start position:0% +Um, + + + align:start position:0% +Um, +actually let me let me say it in a + + align:start position:0% +actually let me let me say it in a + + + align:start position:0% +actually let me let me say it in a +different order. So let's say so U is + + align:start position:0% +different order. So let's say so U is + + + align:start position:0% +different order. So let's say so U is +that matrix and V is this matrix which + + align:start position:0% +that matrix and V is this matrix which + + + align:start position:0% +that matrix and V is this matrix which +is very similar to U and we'll make the + + align:start position:0% +is very similar to U and we'll make the + + + align:start position:0% +is very similar to U and we'll make the +remark that so exercise this point I + + align:start position:0% +remark that so exercise this point I + + + align:start position:0% +remark that so exercise this point I +won't include the details U and V + + align:start position:0% +won't include the details U and V + + + align:start position:0% +won't include the details U and V +generate + + align:start position:0% +generate + + + align:start position:0% +generate +SL2 + + align:start position:0% + + + + align:start position:0% + +okay if you play around a little bit you + + align:start position:0% +okay if you play around a little bit you + + + align:start position:0% +okay if you play around a little bit you +you can see this all right so therefore + + align:start position:0% +you can see this all right so therefore + + + align:start position:0% +you can see this all right so therefore +if we have a non-trivial representation + + align:start position:0% +if we have a non-trivial representation + + + align:start position:0% +if we have a non-trivial representation +these cannot both go to the identity. + + align:start position:0% +these cannot both go to the identity. + + + align:start position:0% +these cannot both go to the identity. +So row is non-trivial. + + align:start position:0% + + + + align:start position:0% + +So either row of u or row of v is not + + align:start position:0% +So either row of u or row of v is not + + + align:start position:0% +So either row of u or row of v is not +the identity. And u and v are so similar + + align:start position:0% +the identity. And u and v are so similar + + + align:start position:0% +the identity. And u and v are so similar +to each other it doesn't really matter + + align:start position:0% +to each other it doesn't really matter + + + align:start position:0% +to each other it doesn't really matter +which one. So I'm going to say + + align:start position:0% +which one. So I'm going to say + + + align:start position:0% +which one. So I'm going to say +essentially without loss of generality + + align:start position:0% +essentially without loss of generality + + + align:start position:0% +essentially without loss of generality +row of u is not the identity. + + align:start position:0% + + + + align:start position:0% + +All right. Now let's think about row of + + align:start position:0% +All right. Now let's think about row of + + + align:start position:0% +All right. Now let's think about row of +u. Um + + align:start position:0% + + + + align:start position:0% + +there's something quite special about + + align:start position:0% +there's something quite special about + + + align:start position:0% +there's something quite special about +this matrix which is um + + align:start position:0% +this matrix which is um + + + align:start position:0% +this matrix which is um +um that it is conjugate + + align:start position:0% +um that it is conjugate + + + align:start position:0% +um that it is conjugate +to powers of itself. + + align:start position:0% +to powers of itself. + + + align:start position:0% +to powers of itself. +Let me write that down. So suppose take + + align:start position:0% +Let me write that down. So suppose take + + + align:start position:0% +Let me write that down. So suppose take +a diagonal matrix A a inverse. I put + + align:start position:0% +a diagonal matrix A a inverse. I put + + + align:start position:0% +a diagonal matrix A a inverse. I put +this matrix in the middle + + align:start position:0% +this matrix in the middle + + + align:start position:0% +this matrix in the middle +and then I want to conjugate it. So now + + align:start position:0% +and then I want to conjugate it. So now + + + align:start position:0% +and then I want to conjugate it. So now +I put on the other side the inverse. + + align:start position:0% +I put on the other side the inverse. + + + align:start position:0% +I put on the other side the inverse. +Right? So this is the conjugate of my + + align:start position:0% +Right? So this is the conjugate of my + + + align:start position:0% +Right? So this is the conjugate of my +matrix U. + + align:start position:0% +matrix U. + + + align:start position:0% +matrix U. +Okay. + + align:start position:0% +Okay. + + + align:start position:0% +Okay. +So I multiply this by this. Uh I + + align:start position:0% +So I multiply this by this. Uh I + + + align:start position:0% +So I multiply this by this. Uh I +multiply the top row by a and the bottom + + align:start position:0% +multiply the top row by a and the bottom + + + align:start position:0% +multiply the top row by a and the bottom +row by a inverse. So I get a a z a + + align:start position:0% +row by a inverse. So I get a a z a + + + align:start position:0% +row by a inverse. So I get a a z a +inverse. And then I still have this guy. + + align:start position:0% + + + + align:start position:0% + +Now when I multiply these matrices + + align:start position:0% +Now when I multiply these matrices + + + align:start position:0% +Now when I multiply these matrices +together, I multiply the left column by + + align:start position:0% +together, I multiply the left column by + + + align:start position:0% +together, I multiply the left column by +a inverse and the right column by a. + + align:start position:0% +a inverse and the right column by a. + + + align:start position:0% +a inverse and the right column by a. +The diagonals cancel, but I get one 01 + + align:start position:0% +The diagonals cancel, but I get one 01 + + + align:start position:0% +The diagonals cancel, but I get one 01 +a². + + align:start position:0% + + + + align:start position:0% + +Okay. + + align:start position:0% + + + + align:start position:0% + +So see that u is conjugate + + align:start position:0% +So see that u is conjugate + + + align:start position:0% +So see that u is conjugate +to + + align:start position:0% +to + + + align:start position:0% +to +u to the power a squ + + align:start position:0% +u to the power a squ + + + align:start position:0% +u to the power a squ +and this is for any a + + align:start position:0% + + + + align:start position:0% + +right. + + align:start position:0% +right. + + + align:start position:0% +right. +So that is a special and really + + align:start position:0% +So that is a special and really + + + align:start position:0% +So that is a special and really +interesting feature of this element of + + align:start position:0% +interesting feature of this element of + + + align:start position:0% +interesting feature of this element of +my group. + + align:start position:0% +my group. + + + align:start position:0% +my group. +And so now I have a representation and + + align:start position:0% +And so now I have a representation and + + + align:start position:0% +And so now I have a representation and +row of u is conjugate to row of u of a 2 + + align:start position:0% +row of u is conjugate to row of u of a 2 + + + align:start position:0% +row of u is conjugate to row of u of a 2 +which is row of u to the a 2. So now I + + align:start position:0% +which is row of u to the a 2. So now I + + + align:start position:0% +which is row of u to the a 2. So now I +have a matrix I have a unitary matrix + + align:start position:0% +have a matrix I have a unitary matrix + + + align:start position:0% +have a matrix I have a unitary matrix +and it is conjugate to a big power of + + align:start position:0% +and it is conjugate to a big power of + + + align:start position:0% +and it is conjugate to a big power of +itself. + + align:start position:0% +itself. + + + align:start position:0% +itself. +Okay, in the world of matrices, it's not + + align:start position:0% +Okay, in the world of matrices, it's not + + + align:start position:0% +Okay, in the world of matrices, it's not +so easy to get that to happen. So, this + + align:start position:0% +so easy to get that to happen. So, this + + + align:start position:0% +so easy to get that to happen. So, this +group has a has an interesting property + + align:start position:0% +group has a has an interesting property + + + align:start position:0% +group has a has an interesting property +that has an element which is conjugate + + align:start position:0% +that has an element which is conjugate + + + align:start position:0% +that has an element which is conjugate +to many different powers of itself. + + align:start position:0% +to many different powers of itself. + + + align:start position:0% +to many different powers of itself. +And in matrices, it's not so easy to + + align:start position:0% +And in matrices, it's not so easy to + + + align:start position:0% +And in matrices, it's not so easy to +find a matrix which is conjugate to many + + align:start position:0% +find a matrix which is conjugate to many + + + align:start position:0% +find a matrix which is conjugate to many +different powers of itself. + + align:start position:0% +different powers of itself. + + + align:start position:0% +different powers of itself. +Why? because + + align:start position:0% +Why? because + + + align:start position:0% +Why? because +uh uh- because of how the igen values + + align:start position:0% +uh uh- because of how the igen values + + + align:start position:0% +uh uh- because of how the igen values +behave. + + align:start position:0% +behave. + + + align:start position:0% +behave. +So + + align:start position:0% +So + + + align:start position:0% +So +okay. So so now let's think about IGEN + + align:start position:0% +okay. So so now let's think about IGEN + + + align:start position:0% +okay. So so now let's think about IGEN +values. + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% + + + + align:start position:0% + +Okay. + + align:start position:0% +Okay. + + + align:start position:0% +Okay. +So + + align:start position:0% +So + + + align:start position:0% +So +row of U is U of D is a matrix. + + align:start position:0% + + + + align:start position:0% + +And if row of u is conjugate to row of u + + align:start position:0% +And if row of u is conjugate to row of u + + + align:start position:0% +And if row of u is conjugate to row of u +to the a^2 + + align:start position:0% +to the a^2 + + + align:start position:0% +to the a^2 +then that tells us that the igen values + + align:start position:0% +then that tells us that the igen values + + + align:start position:0% +then that tells us that the igen values +the spectrum of row of u is the same as + + align:start position:0% +the spectrum of row of u is the same as + + + align:start position:0% +the spectrum of row of u is the same as +the igen values of row of u to the a^ 2. + + align:start position:0% +the igen values of row of u to the a^ 2. + + + align:start position:0% +the igen values of row of u to the a^ 2. +Two conjugate matrices have the same + + align:start position:0% +Two conjugate matrices have the same + + + align:start position:0% +Two conjugate matrices have the same +igen values. + + align:start position:0% +igen values. + + + align:start position:0% +igen values. +But if you take a matrix and raise it to + + align:start position:0% +But if you take a matrix and raise it to + + + align:start position:0% +But if you take a matrix and raise it to +a power, the igen values are all raised + + align:start position:0% +a power, the igen values are all raised + + + align:start position:0% +a power, the igen values are all raised +to a power. So this is the igen values + + align:start position:0% +to a power. So this is the igen values + + + align:start position:0% +to a power. So this is the igen values +of row of u to the a 2. + + align:start position:0% + + + + align:start position:0% + +Okay. + + align:start position:0% +Okay. + + + align:start position:0% +Okay. +Okay. So for instance, you could take a + + align:start position:0% +Okay. So for instance, you could take a + + + align:start position:0% +Okay. So for instance, you could take a +to be two and it tells you if you have + + align:start position:0% +to be two and it tells you if you have + + + align:start position:0% +to be two and it tells you if you have +an igen value of row of u you raise it + + align:start position:0% +an igen value of row of u you raise it + + + align:start position:0% +an igen value of row of u you raise it +to the fourth power that will also be an + + align:start position:0% +to the fourth power that will also be an + + + align:start position:0% +to the fourth power that will also be an +igen value of row of u. And you can keep + + align:start position:0% +igen value of row of u. And you can keep + + + align:start position:0% +igen value of row of u. And you can keep +doing that. And it's not just four. We + + align:start position:0% +doing that. And it's not just four. We + + + align:start position:0% +doing that. And it's not just four. We +have many choices for a squ. + + align:start position:0% + + + + align:start position:0% + +Okay. So let's think about what the igen + + align:start position:0% +Okay. So let's think about what the igen + + + align:start position:0% +Okay. So let's think about what the igen +values of row of u may be like. So study + + align:start position:0% +values of row of u may be like. So study + + + align:start position:0% +values of row of u may be like. So study +values of row of u. So this is an an + + align:start position:0% +values of row of u. So this is an an + + + align:start position:0% +values of row of u. So this is an an +amazing fact about them. And there's a + + align:start position:0% +amazing fact about them. And there's a + + + align:start position:0% +amazing fact about them. And there's a +more pedestrian fact that we should also + + align:start position:0% +more pedestrian fact that we should also + + + align:start position:0% +more pedestrian fact that we should also +observe. We know that u to the p is the + + align:start position:0% +observe. We know that u to the p is the + + + align:start position:0% +observe. We know that u to the p is the +identity. + + align:start position:0% +identity. + + + align:start position:0% +identity. +And therefore + + align:start position:0% +And therefore + + + align:start position:0% +And therefore +row of u to the p is the identity. So + + align:start position:0% +row of u to the p is the identity. So + + + align:start position:0% +row of u to the p is the identity. So +then if lambda is an igen value of row + + align:start position:0% +then if lambda is an igen value of row + + + align:start position:0% +then if lambda is an igen value of row +of u then we get that lambda to the p is + + align:start position:0% +of u then we get that lambda to the p is + + + align:start position:0% +of u then we get that lambda to the p is +the is one. Okay. So the igen values of + + align:start position:0% +the is one. Okay. So the igen values of + + + align:start position:0% +the is one. Okay. So the igen values of +row of u they're all p roots of unity. + + align:start position:0% + + + + align:start position:0% + +Um + + align:start position:0% +Um + + + align:start position:0% +Um +right so we get the following. If lambda + + align:start position:0% +right so we get the following. If lambda + + + align:start position:0% +right so we get the following. If lambda +is an igen value of row of u then lambda + + align:start position:0% +is an igen value of row of u then lambda + + + align:start position:0% +is an igen value of row of u then lambda +to the p is one and lambda to the a 2 is + + align:start position:0% +to the p is one and lambda to the a 2 is + + + align:start position:0% +to the p is one and lambda to the a 2 is +also an igen value of row of u. + + align:start position:0% + + + + align:start position:0% + +Okay. + + align:start position:0% +Okay. + + + align:start position:0% +Okay. +So + + align:start position:0% +So + + + align:start position:0% +So +um since lambda to the p is one, we only + + align:start position:0% +um since lambda to the p is one, we only + + + align:start position:0% +um since lambda to the p is one, we only +care about a^2 mod p. So could put mod p + + align:start position:0% +care about a^2 mod p. So could put mod p + + + align:start position:0% +care about a^2 mod p. So could put mod p +there. + + align:start position:0% +there. + + + align:start position:0% +there. +Um and um + + align:start position:0% +Um and um + + + align:start position:0% +Um and um +there are p min -1 / 2 quadratic + + align:start position:0% +there are p min -1 / 2 quadratic + + + align:start position:0% +there are p min -1 / 2 quadratic +residues + + align:start position:0% +residues + + + align:start position:0% +residues +mod p. + + align:start position:0% +mod p. + + + align:start position:0% +mod p. +So this a^ squ mod p. It could be any + + align:start position:0% +So this a^ squ mod p. It could be any + + + align:start position:0% +So this a^ squ mod p. It could be any +quadratic residue mod p. There are p + + align:start position:0% +quadratic residue mod p. There are p + + + align:start position:0% +quadratic residue mod p. There are p +minus one over two of them. And if you + + align:start position:0% +minus one over two of them. And if you + + + align:start position:0% +minus one over two of them. And if you +take a p of unity and you raise it to a + + align:start position:0% +take a p of unity and you raise it to a + + + align:start position:0% +take a p of unity and you raise it to a +power it's between one and p you'll + + align:start position:0% +power it's between one and p you'll + + + align:start position:0% +power it's between one and p you'll +you'll change it. So so lambda is a + + align:start position:0% +you'll change it. So so lambda is a + + + align:start position:0% +you'll change it. So so lambda is a +primitive. So if lambda is not one + + align:start position:0% +primitive. So if lambda is not one + + + align:start position:0% +primitive. So if lambda is not one +then lambda is a primitive p root of + + align:start position:0% +then lambda is a primitive p root of + + + align:start position:0% +then lambda is a primitive p root of +unity + + align:start position:0% + + + + align:start position:0% + +and that tells us that the lambda to the + + align:start position:0% +and that tells us that the lambda to the + + + align:start position:0% +and that tells us that the lambda to the +a^ 2 mod p are all distinct + + align:start position:0% +a^ 2 mod p are all distinct + + + align:start position:0% +a^ 2 mod p are all distinct +for the p minus one over two quadratic + + align:start position:0% +for the p minus one over two quadratic + + + align:start position:0% +for the p minus one over two quadratic +reserves. + + align:start position:0% +reserves. + + + align:start position:0% +reserves. +Okay, so we now have seen that that + + align:start position:0% +Okay, so we now have seen that that + + + align:start position:0% +Okay, so we now have seen that that +there are an awful lot of different igen + + align:start position:0% +there are an awful lot of different igen + + + align:start position:0% +there are an awful lot of different igen +values which can only happen if the + + align:start position:0% +values which can only happen if the + + + align:start position:0% +values which can only happen if the +matrix is in a large dimension. + + align:start position:0% +matrix is in a large dimension. + + + align:start position:0% +matrix is in a large dimension. +So that gives us that d is at least p + + + align:start position:0% +So that gives us that d is at least p + + + + align:start position:0% +So that gives us that d is at least p + +1 / 2. + + align:start position:0% + + + + align:start position:0% + +Okay, actually I so how do we know that + + align:start position:0% +Okay, actually I so how do we know that + + + align:start position:0% +Okay, actually I so how do we know that +row of u has a not an igen value that's + + align:start position:0% +row of u has a not an igen value that's + + + align:start position:0% +row of u has a not an igen value that's +not one? Well, if all the igen values + + align:start position:0% +not one? Well, if all the igen values + + + align:start position:0% +not one? Well, if all the igen values +were one, then row of u you you could is + + align:start position:0% +were one, then row of u you you could is + + + align:start position:0% +were one, then row of u you you could is +conjugate to a matrix with ones on the + + align:start position:0% +conjugate to a matrix with ones on the + + + align:start position:0% +conjugate to a matrix with ones on the +diagonals and some upper triangular + + align:start position:0% +diagonals and some upper triangular + + + align:start position:0% +diagonals and some upper triangular +stuff. And if you raise that to a power, + + align:start position:0% +stuff. And if you raise that to a power, + + + align:start position:0% +stuff. And if you raise that to a power, +you'll never get the identity. Um + + align:start position:0% +you'll never get the identity. Um + + + align:start position:0% +you'll never get the identity. Um +an exercise. So there's a little a + + align:start position:0% +an exercise. So there's a little a + + + align:start position:0% +an exercise. So there's a little a +little something where exercise. + + align:start position:0% +little something where exercise. + + + align:start position:0% +little something where exercise. +If um the igen values of row of u are + + align:start position:0% +If um the igen values of row of u are + + + align:start position:0% +If um the igen values of row of u are +exactly the set one + + align:start position:0% +exactly the set one + + + align:start position:0% +exactly the set one +and + + align:start position:0% +and + + + align:start position:0% +and +row of u to the p = 1 then row of u is + + align:start position:0% +row of u to the p = 1 then row of u is + + + align:start position:0% +row of u to the p = 1 then row of u is +the identity + + align:start position:0% +the identity + + + align:start position:0% +the identity +I I'll leave the matrix details. + + align:start position:0% + + + + align:start position:0% + +Okay. + + align:start position:0% +Okay. + + + align:start position:0% +Okay. +So all the representations of SL2 are + + align:start position:0% +So all the representations of SL2 are + + + align:start position:0% +So all the representations of SL2 are +really big. Why does that matter? + + align:start position:0% +really big. Why does that matter? + + + align:start position:0% +really big. Why does that matter? +Let's do another proposition. + + align:start position:0% + + + + align:start position:0% + +So proposition two + + align:start position:0% + + + + align:start position:0% + +you take sigma 1 of t mu. So mu is a + + align:start position:0% +you take sigma 1 of t mu. So mu is a + + + align:start position:0% +you take sigma 1 of t mu. So mu is a +measure on + + align:start position:0% +measure on + + + align:start position:0% +measure on +probability measure on SL2 FP. + + align:start position:0% + + + + align:start position:0% + +Then sigma 1 of this guy if you square + + align:start position:0% +Then sigma 1 of this guy if you square + + + align:start position:0% +Then sigma 1 of this guy if you square +it and you multiply by D +1 / 2 that is + + align:start position:0% +it and you multiply by D +1 / 2 that is + + + align:start position:0% +it and you multiply by D +1 / 2 that is +at most the size of SL2FP + + align:start position:0% +at most the size of SL2FP + + + align:start position:0% +at most the size of SL2FP +times mu L2. + + align:start position:0% + + + + align:start position:0% + +Simplifying the algebra a little bit, + + align:start position:0% +Simplifying the algebra a little bit, + + + align:start position:0% +Simplifying the algebra a little bit, +sigma 1 of t mu^2 is smaller than around + + align:start position:0% +sigma 1 of t mu^2 is smaller than around + + + align:start position:0% +sigma 1 of t mu^2 is smaller than around +1 over p^2 + + align:start position:0% +1 over p^2 + + + align:start position:0% +1 over p^2 +time mu l2. + + align:start position:0% + + + + align:start position:0% + +Okay. + + align:start position:0% + + + + align:start position:0% + +All right. So we come back to the + + align:start position:0% +All right. So we come back to the + + + align:start position:0% +All right. So we come back to the +question from earlier in the class. How + + align:start position:0% +question from earlier in the class. How + + + align:start position:0% +question from earlier in the class. How +are singular values related to igen + + align:start position:0% +are singular values related to igen + + + align:start position:0% +are singular values related to igen +values? + + align:start position:0% +values? + + + align:start position:0% +values? +So sigma i of t mu + + align:start position:0% +So sigma i of t mu + + + align:start position:0% +So sigma i of t mu +squared is lambda i of t mu t mu star. + + align:start position:0% +squared is lambda i of t mu t mu star. + + + align:start position:0% +squared is lambda i of t mu t mu star. +It's the ien value of this matrix. + + align:start position:0% +It's the ien value of this matrix. + + + align:start position:0% +It's the ien value of this matrix. +And the key observation is that the igen + + align:start position:0% +And the key observation is that the igen + + + align:start position:0% +And the key observation is that the igen +spaces of this matrix have a g action on + + align:start position:0% +spaces of this matrix have a g action on + + + align:start position:0% +spaces of this matrix have a g action on +them. And except for the constant + + align:start position:0% +them. And except for the constant + + + align:start position:0% +them. And except for the constant +functions the igen spaces are not + + align:start position:0% +functions the igen spaces are not + + + align:start position:0% +functions the igen spaces are not +trivial. Here's the key + + align:start position:0% + + + + align:start position:0% + +spaces + + align:start position:0% +spaces + + + align:start position:0% +spaces +of t mu t mu star have a g action + + align:start position:0% +of t mu t mu star have a g action + + + align:start position:0% +of t mu t mu star have a g action +and except for + + align:start position:0% +and except for + + + align:start position:0% +and except for +the constant functions. So the constant + + align:start position:0% +the constant functions. So the constant + + + align:start position:0% +the constant functions. So the constant +functions are an igen space of t mu tu + + align:start position:0% +functions are an igen space of t mu tu + + + align:start position:0% +functions are an igen space of t mu tu +star but all the other ones it's a + + align:start position:0% +star but all the other ones it's a + + + align:start position:0% +star but all the other ones it's a +non-trivial action. + + align:start position:0% + + + + align:start position:0% + +Let's suppose that for a moment and see + + align:start position:0% +Let's suppose that for a moment and see + + + align:start position:0% +Let's suppose that for a moment and see +why it's helpful and then we can think + + align:start position:0% +why it's helpful and then we can think + + + align:start position:0% +why it's helpful and then we can think +more carefully about what exactly are + + align:start position:0% +more carefully about what exactly are + + + align:start position:0% +more carefully about what exactly are +the igen spaces. + + align:start position:0% +the igen spaces. + + + align:start position:0% +the igen spaces. +Um. + + align:start position:0% + + + + align:start position:0% + +All right. + + align:start position:0% + + + + align:start position:0% + +Um + + align:start position:0% + + + + align:start position:0% + +Okay. + + align:start position:0% +Okay. + + + align:start position:0% +Okay. +Um so that tells us that sig each sigma + + align:start position:0% +Um so that tells us that sig each sigma + + + align:start position:0% +Um so that tells us that sig each sigma +i + + align:start position:0% + + + + align:start position:0% + +has a multiplicity + + align:start position:0% +has a multiplicity + + + align:start position:0% +has a multiplicity +which is at least d + 1 / 2. + + align:start position:0% +which is at least d + 1 / 2. + + + align:start position:0% +which is at least d + 1 / 2. +So you have and we really care about the + + align:start position:0% +So you have and we really care about the + + + align:start position:0% +So you have and we really care about the +biggest one, this biggest singular + + align:start position:0% +biggest one, this biggest singular + + + align:start position:0% +biggest one, this biggest singular +vector. There's not just one biggest + + align:start position:0% +vector. There's not just one biggest + + + align:start position:0% +vector. There's not just one biggest +singular vector, but there's a a whole + + align:start position:0% +singular vector, but there's a a whole + + + align:start position:0% +singular vector, but there's a a whole +singular subspace of a big dimension and + + align:start position:0% +singular subspace of a big dimension and + + + align:start position:0% +singular subspace of a big dimension and +all of those vectors have have this + + align:start position:0% +all of those vectors have have this + + + align:start position:0% +all of those vectors have have this +large singular value. + + align:start position:0% +large singular value. + + + align:start position:0% +large singular value. +Okay. So now another uh fact from linear + + align:start position:0% +Okay. So now another uh fact from linear + + + align:start position:0% +Okay. So now another uh fact from linear +algebra is that if you add up the + + align:start position:0% +algebra is that if you add up the + + + align:start position:0% +algebra is that if you add up the +singular values squared of a of a matrix + + align:start position:0% +singular values squared of a of a matrix + + + align:start position:0% +singular values squared of a of a matrix +with multiplicity + + align:start position:0% + + + + align:start position:0% + +that is the Hilbert Schmidt norm of the + + align:start position:0% +that is the Hilbert Schmidt norm of the + + + align:start position:0% +that is the Hilbert Schmidt norm of the +matrix. So it's the sum of the entries + + align:start position:0% +matrix. So it's the sum of the entries + + + align:start position:0% +matrix. So it's the sum of the entries +of the matrix. + + align:start position:0% +of the matrix. + + + align:start position:0% +of the matrix. +Uh + + align:start position:0% + + + + align:start position:0% + +so this is a matrix where the rows and + + align:start position:0% +so this is a matrix where the rows and + + + align:start position:0% +so this is a matrix where the rows and +columns are indexed by our group G. So + + align:start position:0% +columns are indexed by our group G. So + + + align:start position:0% +columns are indexed by our group G. So +it has an entry G1 G2 and it's the sum + + align:start position:0% +it has an entry G1 G2 and it's the sum + + + align:start position:0% +it has an entry G1 G2 and it's the sum +of the entries squared. + + align:start position:0% + + + + align:start position:0% + +Does this look familiar to people from + + align:start position:0% +Does this look familiar to people from + + + align:start position:0% +Does this look familiar to people from +linear algebra? + + align:start position:0% +linear algebra? + + + align:start position:0% +linear algebra? +Okay. Okay. Now the entries of our + + align:start position:0% +Okay. Okay. Now the entries of our + + + align:start position:0% +Okay. Okay. Now the entries of our +matrix we can read off. It's the sum g1 + + align:start position:0% +matrix we can read off. It's the sum g1 + + + align:start position:0% +matrix we can read off. It's the sum g1 +g2 + + align:start position:0% +g2 + + + align:start position:0% +g2 +mu of something like g1 g2 inverse. This + + align:start position:0% +mu of something like g1 g2 inverse. This + + + align:start position:0% +mu of something like g1 g2 inverse. This +might not be exactly right but it's the + + align:start position:0% +might not be exactly right but it's the + + + align:start position:0% +might not be exactly right but it's the +right idea. + + align:start position:0% +right idea. + + + align:start position:0% +right idea. +>> Uh that's that's the entry and then + + align:start position:0% +>> Uh that's that's the entry and then + + + align:start position:0% +>> Uh that's that's the entry and then +we're squaring it. + + align:start position:0% +we're squaring it. + + + align:start position:0% +we're squaring it. +Um and so that's the size of the group + + align:start position:0% +Um and so that's the size of the group + + + align:start position:0% +Um and so that's the size of the group +times the sum of mu of g^2. + + align:start position:0% + + + + align:start position:0% + +Okay, so that's the right hand side + + align:start position:0% +Okay, so that's the right hand side + + + align:start position:0% +Okay, so that's the right hand side +and over here we're counting with + + align:start position:0% +and over here we're counting with + + + align:start position:0% +and over here we're counting with +multiplicity and the multiplicity is + + align:start position:0% +multiplicity and the multiplicity is + + + align:start position:0% +multiplicity and the multiplicity is +always large. So this is at least d + 1 + + align:start position:0% +always large. So this is at least d + 1 + + + align:start position:0% +always large. So this is at least d + 1 +/ 2 * sigma 1 of t mu^ 2 + + align:start position:0% + + + + align:start position:0% + +So there's an important difference + + align:start position:0% +So there's an important difference + + + align:start position:0% +So there's an important difference +between the sigma 1 and the sigma 0. The + + align:start position:0% +between the sigma 1 and the sigma 0. The + + + align:start position:0% +between the sigma 1 and the sigma 0. The +sigma 0 went with the constant functions + + align:start position:0% +sigma 0 went with the constant functions + + + align:start position:0% +sigma 0 went with the constant functions +that lives in a space of dimension one. + + align:start position:0% +that lives in a space of dimension one. + + + align:start position:0% +that lives in a space of dimension one. +But anybody else lives in a big + + align:start position:0% +But anybody else lives in a big + + + align:start position:0% +But anybody else lives in a big +dimensional space. And so this uh counts + + align:start position:0% +dimensional space. And so this uh counts + + + align:start position:0% +dimensional space. And so this uh counts +get gets counted many times. Um and and + + align:start position:0% +get gets counted many times. Um and and + + + align:start position:0% +get gets counted many times. Um and and +that changes the playing field. + + align:start position:0% + + + + align:start position:0% + +Um, what is D? + + align:start position:0% +Um, what is D? + + + align:start position:0% +Um, what is D? +>> What is D? Sorry. D is P. Sorry. + + align:start position:0% + + + + align:start position:0% + +Thank you. + + align:start position:0% +Thank you. + + + align:start position:0% +Thank you. +Okay. Is it right up there? Yeah. So, D + + align:start position:0% +Okay. Is it right up there? Yeah. So, D + + + align:start position:0% +Okay. Is it right up there? Yeah. So, D +is the dimension of the representation, + + align:start position:0% +is the dimension of the representation, + + + align:start position:0% +is the dimension of the representation, +but um that's why I put it, but it's a + + align:start position:0% +but um that's why I put it, but it's a + + + align:start position:0% +but um that's why I put it, but it's a +it was just a mistake. It's supposed to + + align:start position:0% +it was just a mistake. It's supposed to + + + align:start position:0% +it was just a mistake. It's supposed to +be P+ one over two. + + align:start position:0% +be P+ one over two. + + + align:start position:0% +be P+ one over two. +So what needs to be spelled out more + + align:start position:0% +So what needs to be spelled out more + + + align:start position:0% +So what needs to be spelled out more +carefully? + + align:start position:0% +carefully? + + + align:start position:0% +carefully? +I think we should just spell out a + + align:start position:0% +I think we should just spell out a + + + align:start position:0% +I think we should just spell out a +little more carefully why the spaces + + align:start position:0% +little more carefully why the spaces + + + align:start position:0% +little more carefully why the spaces +have this G action. + + align:start position:0% + + + + align:start position:0% + +Okay, so first of all, what is T mu + + align:start position:0% +Okay, so first of all, what is T mu + + + align:start position:0% +Okay, so first of all, what is T mu +star? Let's say mu star of g is just mu + + align:start position:0% +star? Let's say mu star of g is just mu + + + align:start position:0% +star? Let's say mu star of g is just mu +of g inverse. And if you write down the + + align:start position:0% +of g inverse. And if you write down the + + + align:start position:0% +of g inverse. And if you write down the +definition of the adjint and play around + + align:start position:0% +definition of the adjint and play around + + + align:start position:0% +definition of the adjint and play around +a little bit, you'll see that t mu star + + align:start position:0% +a little bit, you'll see that t mu star + + + align:start position:0% +a little bit, you'll see that t mu star +is just t of u star convoling with you. + + align:start position:0% +is just t of u star convoling with you. + + + align:start position:0% +is just t of u star convoling with you. +So t mu t mu star of that is just you + + align:start position:0% +So t mu t mu star of that is just you + + + align:start position:0% +So t mu t mu star of that is just you +take f you convolve it with mu star and + + align:start position:0% +take f you convolve it with mu star and + + + align:start position:0% +take f you convolve it with mu star and +then you convolve it with mu. So it's t + + align:start position:0% +then you convolve it with mu. So it's t + + + align:start position:0% +then you convolve it with mu. So it's t +of uh mu convolve with mu star. + + align:start position:0% + + + + align:start position:0% + +Okay so our oper our operator is still + + align:start position:0% +Okay so our oper our operator is still + + + align:start position:0% +Okay so our oper our operator is still +just a convolution operator just + + align:start position:0% +just a convolution operator just + + + align:start position:0% +just a convolution operator just +convolving by something slightly + + align:start position:0% +convolving by something slightly + + + align:start position:0% +convolving by something slightly +different. And now we want to see that + + align:start position:0% +different. And now we want to see that + + + align:start position:0% +different. And now we want to see that +convolution + + align:start position:0% +convolution + + + align:start position:0% +convolution +uh commutes with the some symmetries of + + align:start position:0% +uh commutes with the some symmetries of + + + align:start position:0% +uh commutes with the some symmetries of +of g. + + align:start position:0% +of g. + + + align:start position:0% +of g. +Um okay so our convolution has been + + align:start position:0% +Um okay so our convolution has been + + + align:start position:0% +Um okay so our convolution has been +defined to be on the right and so I + + align:start position:0% +defined to be on the right and so I + + + align:start position:0% +defined to be on the right and so I +think it's supposed to commute with the + + align:start position:0% +think it's supposed to commute with the + + + align:start position:0% +think it's supposed to commute with the +symmetries of of f on the left. So let's + + align:start position:0% +symmetries of of f on the left. So let's + + + align:start position:0% +symmetries of of f on the left. So let's +say f the left action of g on f of h is + + align:start position:0% +say f the left action of g on f of h is + + + align:start position:0% +say f the left action of g on f of h is +f of + + align:start position:0% +f of + + + align:start position:0% +f of +g inverse h. + + align:start position:0% + + + + align:start position:0% + +I want to say that uh convolution + + align:start position:0% +I want to say that uh convolution + + + align:start position:0% +I want to say that uh convolution +commutes with this action. So I want to + + align:start position:0% +commutes with this action. So I want to + + + align:start position:0% +commutes with this action. So I want to +say claim + + align:start position:0% +say claim + + + align:start position:0% +say claim +that for for any measure new + + align:start position:0% + + + + align:start position:0% + +if I take T new of left action G of F + + align:start position:0% +if I take T new of left action G of F + + + align:start position:0% +if I take T new of left action G of F +this is left action G T new of F. + + align:start position:0% +this is left action G T new of F. + + + align:start position:0% +this is left action G T new of F. +Okay, cross my finger that I wrote + + align:start position:0% +Okay, cross my finger that I wrote + + + align:start position:0% +Okay, cross my finger that I wrote +everything correctly so that this is + + align:start position:0% +everything correctly so that this is + + + align:start position:0% +everything correctly so that this is +true. + + align:start position:0% +true. + + + align:start position:0% +true. +uh t new of left action g of f at some + + align:start position:0% +uh t new of left action g of f at some + + + align:start position:0% +uh t new of left action g of f at some +um + + align:start position:0% +um + + + align:start position:0% +um +let's say I evaluate that at x. + + align:start position:0% +let's say I evaluate that at x. + + + align:start position:0% +let's say I evaluate that at x. +So the I'm going to convolve this + + align:start position:0% +So the I'm going to convolve this + + + align:start position:0% +So the I'm going to convolve this +function with new. So it's lgf convolved + + align:start position:0% +function with new. So it's lgf convolved + + + align:start position:0% +function with new. So it's lgf convolved +with new at x. So it's the sum x1 x2 = x + + align:start position:0% +with new at x. So it's the sum x1 x2 = x + + + align:start position:0% +with new at x. So it's the sum x1 x2 = x +lf of x1 + + align:start position:0% +lf of x1 + + + align:start position:0% +lf of x1 +new of x2. + + align:start position:0% + + + + align:start position:0% + +So that's the sum x1 x2 = x f of g + + align:start position:0% +So that's the sum x1 x2 = x f of g + + + align:start position:0% +So that's the sum x1 x2 = x f of g +inverse x1 + + align:start position:0% +inverse x1 + + + align:start position:0% +inverse x1 +new of x2. + + align:start position:0% + + + + align:start position:0% + +All right. So the product of these two + + align:start position:0% +All right. So the product of these two + + + align:start position:0% +All right. So the product of these two +guys is g inverse x. + + align:start position:0% +guys is g inverse x. + + + align:start position:0% +guys is g inverse x. +So really the product x1 tilda time x2 + + align:start position:0% +So really the product x1 tilda time x2 + + + align:start position:0% +So really the product x1 tilda time x2 +tilda is g inverse x + + align:start position:0% + + + + align:start position:0% + +um f of x1 tilda new of x2 tilda. + + align:start position:0% + + + + align:start position:0% + +So that is t new of f evaluated at g + + align:start position:0% +So that is t new of f evaluated at g + + + align:start position:0% +So that is t new of f evaluated at g +inverse x. + + align:start position:0% +inverse x. + + + align:start position:0% +inverse x. +So that's lg of t new of f x + + align:start position:0% + + + + align:start position:0% + +probably can see that I'm not a very + + align:start position:0% +probably can see that I'm not a very + + + align:start position:0% +probably can see that I'm not a very +algebraically minded person. I think + + align:start position:0% +algebraically minded person. I think + + + align:start position:0% +algebraically minded person. I think +there's probably a high sort of more + + align:start position:0% +there's probably a high sort of more + + + align:start position:0% +there's probably a high sort of more +highbrow proof of this. So something + + align:start position:0% +highbrow proof of this. So something + + + align:start position:0% +highbrow proof of this. So something +about acting on the left commutes with + + align:start position:0% +about acting on the left commutes with + + + align:start position:0% +about acting on the left commutes with +acting on the right. + + align:start position:0% + + + + align:start position:0% + +Okay. So, + + align:start position:0% +Okay. So, + + + align:start position:0% +Okay. So, +so the group + + align:start position:0% +so the group + + + align:start position:0% +so the group +commutes the group acts on functions and + + align:start position:0% +commutes the group acts on functions and + + + align:start position:0% +commutes the group acts on functions and +that action commutes with this. So, if + + align:start position:0% +that action commutes with this. So, if + + + align:start position:0% +that action commutes with this. So, if +you have an igen space of this, the + + align:start position:0% +you have an igen space of this, the + + + align:start position:0% +you have an igen space of this, the +group will act on it. + + align:start position:0% + + + + align:start position:0% + +So if t new of f is lambda f then t new + + align:start position:0% +So if t new of f is lambda f then t new + + + align:start position:0% +So if t new of f is lambda f then t new +of lgf + + align:start position:0% +of lgf + + + align:start position:0% +of lgf +will be lg t new of f which is lg of + + align:start position:0% +will be lg t new of f which is lg of + + + align:start position:0% +will be lg t new of f which is lg of +lambda f which is lambda lg of f. + + align:start position:0% +lambda f which is lambda lg of f. + + + align:start position:0% +lambda f which is lambda lg of f. +So LG so G + + align:start position:0% +So LG so G + + + align:start position:0% +So LG so G +acts on V lambda the space. + + align:start position:0% + + + + align:start position:0% + +Okay. So that fleshes out + + align:start position:0% +Okay. So that fleshes out + + + align:start position:0% +Okay. So that fleshes out +this. + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +Okay. + + align:start position:0% + + + + align:start position:0% + +Cool. So um let's do a quick application + + align:start position:0% +Cool. So um let's do a quick application + + + align:start position:0% +Cool. So um let's do a quick application +of this to see what we have learned + + align:start position:0% +of this to see what we have learned + + + align:start position:0% +of this to see what we have learned +about mixing. + + align:start position:0% +about mixing. + + + align:start position:0% +about mixing. +So remember that we already know that + + align:start position:0% +So remember that we already know that + + + align:start position:0% +So remember that we already know that +this thing is bounded by one and it's + + align:start position:0% +this thing is bounded by one and it's + + + align:start position:0% +this thing is bounded by one and it's +not at all clear whether this is bigger + + align:start position:0% +not at all clear whether this is bigger + + + align:start position:0% +not at all clear whether this is bigger +or smaller than one. It depends upon mu. + + align:start position:0% +or smaller than one. It depends upon mu. + + + align:start position:0% +or smaller than one. It depends upon mu. +Um if this is bigger than one then this + + align:start position:0% +Um if this is bigger than one then this + + + align:start position:0% +Um if this is bigger than one then this +is kind of useless. But if this is + + align:start position:0% +is kind of useless. But if this is + + + align:start position:0% +is kind of useless. But if this is +smaller than one then it gives us some + + align:start position:0% +smaller than one then it gives us some + + + align:start position:0% +smaller than one then it gives us some +new information. + + align:start position:0% +new information. + + + align:start position:0% +new information. +Okay, + + align:start position:0% + + + + align:start position:0% + +one question about proposition 2. + + align:start position:0% +one question about proposition 2. + + + align:start position:0% +one question about proposition 2. +>> Yeah. + + align:start position:0% +>> Yeah. + + + align:start position:0% +>> Yeah. +>> Does it require the existence of a + + align:start position:0% +>> Does it require the existence of a + + + align:start position:0% +>> Does it require the existence of a +representation of degree P + 1 /2? + + align:start position:0% +representation of degree P + 1 /2? + + + align:start position:0% +representation of degree P + 1 /2? +>> Uh not exactly. I mean this oper this + + align:start position:0% +>> Uh not exactly. I mean this oper this + + + align:start position:0% +>> Uh not exactly. I mean this oper this +operator here has spaces + + align:start position:0% +operator here has spaces + + + align:start position:0% +operator here has spaces +>> and we know that the group acts on them. + + align:start position:0% +>> and we know that the group acts on them. + + + align:start position:0% +>> and we know that the group acts on them. +So therefore there are representations + + align:start position:0% +So therefore there are representations + + + align:start position:0% +So therefore there are representations +of this group. + + align:start position:0% + + + + align:start position:0% + +Okay. + + align:start position:0% +Okay. + + + align:start position:0% +Okay. +So application. + + align:start position:0% + + + + align:start position:0% + +So suppose a is a subset of SL2FP. + + align:start position:0% +So suppose a is a subset of SL2FP. + + + align:start position:0% +So suppose a is a subset of SL2FP. +It doesn't have to be a Selberg just any + + align:start position:0% +It doesn't have to be a Selberg just any + + + align:start position:0% +It doesn't have to be a Selberg just any +subset. And remember that mu of A is the + + align:start position:0% +subset. And remember that mu of A is the + + + align:start position:0% +subset. And remember that mu of A is the +uniform measure on A. + + align:start position:0% + + + + align:start position:0% + +Okay. So what is mu of a L2 squared? + + align:start position:0% +Okay. So what is mu of a L2 squared? + + + align:start position:0% +Okay. So what is mu of a L2 squared? +Well, we square the amplitude of 1 / a^2 + + align:start position:0% +Well, we square the amplitude of 1 / a^2 + + + align:start position:0% +Well, we square the amplitude of 1 / a^2 +and then we add it up and we'll get a + + align:start position:0% +and then we add it up and we'll get a + + + align:start position:0% +and then we add it up and we'll get a +contribution from a points. So we get + + align:start position:0% +contribution from a points. So we get + + + align:start position:0% +contribution from a points. So we get +one over the cardality of a + + align:start position:0% +one over the cardality of a + + + align:start position:0% +one over the cardality of a +right. So if we just plug in our our uh + + align:start position:0% +right. So if we just plug in our our uh + + + align:start position:0% +right. So if we just plug in our our uh +estimate, proposition two + + align:start position:0% +estimate, proposition two + + + align:start position:0% +estimate, proposition two +tells us that sigma 1 of ta squared is + + align:start position:0% +tells us that sigma 1 of ta squared is + + + align:start position:0% +tells us that sigma 1 of ta squared is +bounded by um + + align:start position:0% +bounded by um + + + align:start position:0% +bounded by um +p ^2. + + align:start position:0% + + + + align:start position:0% + +Whoops, + + align:start position:0% +Whoops, + + + align:start position:0% +Whoops, +I did that wrong. That's not good. + + align:start position:0% +I did that wrong. That's not good. + + + align:start position:0% +I did that wrong. That's not good. +This is about p cub. This is about p. + + align:start position:0% +This is about p cub. This is about p. + + + align:start position:0% +This is about p cub. This is about p. +Okay, good. So it's bounded by p ^2 over + + align:start position:0% +Okay, good. So it's bounded by p ^2 over + + + align:start position:0% +Okay, good. So it's bounded by p ^2 over +a. + + align:start position:0% +a. + + + align:start position:0% +a. +So we can see + + align:start position:0% +So we can see + + + align:start position:0% +So we can see +that if a is significantly bigger than p + + align:start position:0% +that if a is significantly bigger than p + + + align:start position:0% +that if a is significantly bigger than p +^2 then sigma 1 of ta is less than one. + + align:start position:0% +^2 then sigma 1 of ta is less than one. + + + align:start position:0% +^2 then sigma 1 of ta is less than one. +So a is 10 p ^2 or even better p 2 plus + + align:start position:0% +So a is 10 p ^2 or even better p 2 plus + + + align:start position:0% +So a is 10 p ^2 or even better p 2 plus +epsilon + + align:start position:0% +epsilon + + + align:start position:0% +epsilon +then sigma 1 is quite a bit less than + + align:start position:0% +then sigma 1 is quite a bit less than + + + align:start position:0% +then sigma 1 is quite a bit less than +one and so this this walk this random + + align:start position:0% +one and so this this walk this random + + + align:start position:0% +one and so this this walk this random +walk will mix. Great. + + align:start position:0% +walk will mix. Great. + + + align:start position:0% +walk will mix. Great. +Um in particular corlary of that is that + + align:start position:0% +Um in particular corlary of that is that + + + align:start position:0% +Um in particular corlary of that is that +if H is a proper subgroup + + align:start position:0% +if H is a proper subgroup + + + align:start position:0% +if H is a proper subgroup +of SL2FP + + align:start position:0% +of SL2FP + + + align:start position:0% +of SL2FP +so we saw earlier take a proper subgroup + + align:start position:0% +so we saw earlier take a proper subgroup + + + align:start position:0% +so we saw earlier take a proper subgroup +and you you walk you just stay in the + + align:start position:0% +and you you walk you just stay in the + + + align:start position:0% +and you you walk you just stay in the +subgroup it won't mix at all sigma 1 + + align:start position:0% +subgroup it won't mix at all sigma 1 + + + align:start position:0% +subgroup it won't mix at all sigma 1 +would be one um then H has size which is + + align:start position:0% +would be one um then H has size which is + + + align:start position:0% +would be one um then H has size which is +smaller than around P ^2 + + align:start position:0% + + + + align:start position:0% + +and we saw earlier that there is a + + align:start position:0% +and we saw earlier that there is a + + + align:start position:0% +and we saw earlier that there is a +subgroup of size about P^2. So this is + + align:start position:0% +subgroup of size about P^2. So this is + + + align:start position:0% +subgroup of size about P^2. So this is +sharp. + + align:start position:0% + + + + align:start position:0% + +Okay. So this addresses the question + + align:start position:0% +Okay. So this addresses the question + + + align:start position:0% +Okay. So this addresses the question +that was raised earlier. The set A may + + align:start position:0% +that was raised earlier. The set A may + + + align:start position:0% +that was raised earlier. The set A may +be large. If you just know the size of + + align:start position:0% +be large. If you just know the size of + + + align:start position:0% +be large. If you just know the size of +A, can you say whether it mixes or not? + + align:start position:0% +A, can you say whether it mixes or not? + + + align:start position:0% +A, can you say whether it mixes or not? +Um this is essentially a sharp answer to + + align:start position:0% +Um this is essentially a sharp answer to + + + align:start position:0% +Um this is essentially a sharp answer to +that question. If A is significantly + + align:start position:0% +that question. If A is significantly + + + align:start position:0% +that question. If A is significantly +bigger than P^2, then the random walk + + align:start position:0% +bigger than P^2, then the random walk + + + align:start position:0% +bigger than P^2, then the random walk +does mix. And if a is smaller than p ^2, + + align:start position:0% +does mix. And if a is smaller than p ^2, + + + align:start position:0% +does mix. And if a is smaller than p ^2, +a could live in a subgroup and the + + align:start position:0% +a could live in a subgroup and the + + + align:start position:0% +a could live in a subgroup and the +random walk may not mix. + + align:start position:0% +random walk may not mix. + + + align:start position:0% +random walk may not mix. +This whole phenomenon is is is quite + + align:start position:0% +This whole phenomenon is is is quite + + + align:start position:0% +This whole phenomenon is is is quite +different from what would happen in a + + align:start position:0% +different from what would happen in a + + + align:start position:0% +different from what would happen in a +commutive group. Um in a commutive + + align:start position:0% +commutive group. Um in a commutive + + + align:start position:0% +commutive group. Um in a commutive +group, you could take very large subsets + + align:start position:0% +group, you could take very large subsets + + + align:start position:0% +group, you could take very large subsets +and still nothing might mix. Um + + align:start position:0% +and still nothing might mix. Um + + + align:start position:0% +and still nothing might mix. Um +partly because the commutive group might + + align:start position:0% +partly because the commutive group might + + + align:start position:0% +partly because the commutive group might +have very large subgroups, but even if + + align:start position:0% +have very large subgroups, but even if + + + align:start position:0% +have very large subgroups, but even if +it doesn't, it wouldn't work. + + align:start position:0% +it doesn't, it wouldn't work. + + + align:start position:0% +it doesn't, it wouldn't work. +Yeah. + + align:start position:0% +Yeah. + + + align:start position:0% +Yeah. +Cool. + + align:start position:0% +Cool. + + + align:start position:0% +Cool. +Okay, so that's all very interesting, + + align:start position:0% +Okay, so that's all very interesting, + + + align:start position:0% +Okay, so that's all very interesting, +but it doesn't look very close to this + + align:start position:0% +but it doesn't look very close to this + + + align:start position:0% +but it doesn't look very close to this +theorem yet because this is theorem says + + align:start position:0% +theorem yet because this is theorem says + + + align:start position:0% +theorem yet because this is theorem says +that we get mixing if our subset has + + align:start position:0% +that we get mixing if our subset has + + + align:start position:0% +that we get mixing if our subset has +size larger than P ^2 and this is a + + align:start position:0% +size larger than P ^2 and this is a + + + align:start position:0% +size larger than P ^2 and this is a +subset of size four. So we will have to + + align:start position:0% +subset of size four. So we will have to + + + align:start position:0% +subset of size four. So we will have to +think some more uh about how to do this + + align:start position:0% +think some more uh about how to do this + + + align:start position:0% +think some more uh about how to do this +and we will talk about that uh next + + align:start position:0% +and we will talk about that uh next + + + align:start position:0% +and we will talk about that uh next +time. \ No newline at end of file diff --git a/QeHuHti530Q.txt b/QeHuHti530Q.txt new file mode 100644 index 0000000000000000000000000000000000000000..cdb39712599105cd87a99c8ecb10982c01e39420 --- /dev/null +++ b/QeHuHti530Q.txt @@ -0,0 +1,8363 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license + + align:start position:0% +a Creative Commons license + + + align:start position:0% +a Creative Commons license +your support will help MIT + + align:start position:0% +your support will help MIT + + + align:start position:0% +your support will help MIT +OpenCourseWare continue to offer high + + align:start position:0% +OpenCourseWare continue to offer high + + + align:start position:0% +OpenCourseWare continue to offer high +quality educational resources for free + + align:start position:0% +quality educational resources for free + + + align:start position:0% +quality educational resources for free +to make a donation or view additional + + align:start position:0% +to make a donation or view additional + + + align:start position:0% +to make a donation or view additional +materials from hundreds of MIT courses + + align:start position:0% +materials from hundreds of MIT courses + + + align:start position:0% +materials from hundreds of MIT courses +visit MIT opencourseware at ocw.mit.edu + + align:start position:0% +visit MIT opencourseware at ocw.mit.edu + + + align:start position:0% +visit MIT opencourseware at ocw.mit.edu +my topic today is they're discussing + + align:start position:0% +my topic today is they're discussing + + + align:start position:0% +my topic today is they're discussing +sensory representations in deep cortex + + align:start position:0% +sensory representations in deep cortex + + + align:start position:0% +sensory representations in deep cortex +like architectures I would say the the + + align:start position:0% +like architectures I would say the the + + + align:start position:0% +like architectures I would say the the +topic is perhaps toward a theory of + + align:start position:0% +topic is perhaps toward a theory of + + + align:start position:0% +topic is perhaps toward a theory of +sensory representations in in deep + + align:start position:0% +sensory representations in in deep + + + align:start position:0% +sensory representations in in deep +networks as you will see the our attempt + + align:start position:0% +networks as you will see the our attempt + + + align:start position:0% +networks as you will see the our attempt +is to develop a systematic theoretical + + align:start position:0% +is to develop a systematic theoretical + + + align:start position:0% +is to develop a systematic theoretical +understanding of the capacity and + + align:start position:0% +understanding of the capacity and + + + align:start position:0% +understanding of the capacity and +limitations of architectures of that of + + align:start position:0% +limitations of architectures of that of + + + align:start position:0% +limitations of architectures of that of +that type the general context is well + + align:start position:0% +that type the general context is well + + + align:start position:0% +that type the general context is well +known in many sensory systems we see + + align:start position:0% +known in many sensory systems we see + + + align:start position:0% +known in many sensory systems we see +information is propagating from from the + + align:start position:0% +information is propagating from from the + + + align:start position:0% +information is propagating from from the +periphery like the retina to visual + + align:start position:0% +periphery like the retina to visual + + + align:start position:0% +periphery like the retina to visual +primary visual cortex and then across + + align:start position:0% +primary visual cortex and then across + + + align:start position:0% +primary visual cortex and then across +many stages up to a very high level or + + align:start position:0% +many stages up to a very high level or + + + align:start position:0% +many stages up to a very high level or +maybe the hippocampal structure it's not + + align:start position:0% +maybe the hippocampal structure it's not + + + align:start position:0% +maybe the hippocampal structure it's not +purely feed-forward + + align:start position:0% +purely feed-forward + + + align:start position:0% +purely feed-forward +there are backward massive backward or + + align:start position:0% +there are backward massive backward or + + + align:start position:0% +there are backward massive backward or +top-down connections that I can't + + align:start position:0% +top-down connections that I can't + + + align:start position:0% +top-down connections that I can't +connections and some of those extra + + align:start position:0% +connections and some of those extra + + + align:start position:0% +connections and some of those extra +features I'll talk about but the most + + align:start position:0% +features I'll talk about but the most + + + align:start position:0% +features I'll talk about but the most +intuitive feature of that is simply + + align:start position:0% +intuitive feature of that is simply + + + align:start position:0% +intuitive feature of that is simply +transformation or filtering of data + + align:start position:0% +transformation or filtering of data + + + align:start position:0% +transformation or filtering of data +across multiple stages + + align:start position:0% +across multiple stages + + + align:start position:0% +across multiple stages +similarly in auditory pathway in other + + align:start position:0% +similarly in auditory pathway in other + + + align:start position:0% +similarly in auditory pathway in other +systems we see a similar structure or + + align:start position:0% +systems we see a similar structure or + + + align:start position:0% +systems we see a similar structure or +aspect of similar structure as well a + + align:start position:0% +aspect of similar structure as well a + + + align:start position:0% +aspect of similar structure as well a +well known and a classical formative + + align:start position:0% +well known and a classical formative + + + align:start position:0% +well known and a classical formative +system for computational science is + + align:start position:0% +system for computational science is + + + align:start position:0% +system for computational science is +bellum where you have information coming + + align:start position:0% +bellum where you have information coming + + + align:start position:0% +bellum where you have information coming +from the mossy fiber layer then expand + + align:start position:0% +from the mossy fiber layer then expand + + + align:start position:0% +from the mossy fiber layer then expand +anonymously into a granule layer and + + align:start position:0% +anonymously into a granule layer and + + + align:start position:0% +anonymously into a granule layer and +then converge to a poke poking yourself + + align:start position:0% +then converge to a poke poking yourself + + + align:start position:0% +then converge to a poke poking yourself +so if you look at a single poke in G + + align:start position:0% +so if you look at a single poke in G + + + align:start position:0% +so if you look at a single poke in G +sell the output of the cerebellum + + align:start position:0% +sell the output of the cerebellum + + + align:start position:0% +sell the output of the cerebellum +as a unit then you see there is a first + + align:start position:0% +as a unit then you see there is a first + + + align:start position:0% +as a unit then you see there is a first +and expansion from one thousand to two + + align:start position:0% +and expansion from one thousand to two + + + align:start position:0% +and expansion from one thousand to two +orders of magnitude or higher in a + + align:start position:0% +orders of magnitude or higher in a + + + align:start position:0% +orders of magnitude or higher in a +granule layer and then convergence of + + align:start position:0% +granule layer and then convergence of + + + align:start position:0% +granule layer and then convergence of +two hundred thousands or so parallel + + align:start position:0% +two hundred thousands or so parallel + + + align:start position:0% +two hundred thousands or so parallel +fibers onto a single poking poking + + align:start position:0% +fibers onto a single poking poking + + + align:start position:0% +fibers onto a single poking poking +yourself and there are those type of + + align:start position:0% +yourself and there are those type of + + + align:start position:0% +yourself and there are those type of +modules many many across the cerebellum + + align:start position:0% +modules many many across the cerebellum + + + align:start position:0% +modules many many across the cerebellum +so again a transformation which involves + + align:start position:0% +so again a transformation which involves + + + align:start position:0% +so again a transformation which involves +in in this case expansion and then + + align:start position:0% +in in this case expansion and then + + + align:start position:0% +in in this case expansion and then +convergence in the basal ganglia which + + align:start position:0% +convergence in the basal ganglia which + + + align:start position:0% +convergence in the basal ganglia which +is not which I wouldn't categorize it as + + align:start position:0% +is not which I wouldn't categorize it as + + + align:start position:0% +is not which I wouldn't categorize it as +a sensory system nevertheless more data + + align:start position:0% +a sensory system nevertheless more data + + + align:start position:0% +a sensory system nevertheless more data +to motor nevertheless you see cortex + + align:start position:0% +to motor nevertheless you see cortex + + + align:start position:0% +to motor nevertheless you see cortex +converging first to various stages of + + align:start position:0% +converging first to various stages of + + + align:start position:0% +converging first to various stages of +the basal ganglia and then expanding + + align:start position:0% +the basal ganglia and then expanding + + + align:start position:0% +the basal ganglia and then expanding +again in to cortex hippocampus has also + + align:start position:0% +again in to cortex hippocampus has also + + + align:start position:0% +again in to cortex hippocampus has also +multiple pathways but some of them + + align:start position:0% +multiple pathways but some of them + + + align:start position:0% +multiple pathways but some of them +include a convergence for instance + + align:start position:0% +include a convergence for instance + + + align:start position:0% +include a convergence for instance +convergence to see a three and then + + align:start position:0% +convergence to see a three and then + + + align:start position:0% +convergence to see a three and then +expansion again to cortex but there are + + align:start position:0% +expansion again to cortex but there are + + + align:start position:0% +expansion again to cortex but there are +other multiple pathways as well + + align:start position:0% +other multiple pathways as well + + + align:start position:0% +other multiple pathways as well +different stages of sensory information + + align:start position:0% +different stages of sensory information + + + align:start position:0% +different stages of sensory information +propagating cause across them okay and + + align:start position:0% +propagating cause across them okay and + + + align:start position:0% +propagating cause across them okay and +finally the artificial network story of + + align:start position:0% +finally the artificial network story of + + + align:start position:0% +finally the artificial network story of +deep neural networks you all of you may + + align:start position:0% +deep neural networks you all of you may + + + align:start position:0% +deep neural networks you all of you may +have heard input layer then sequence of + + align:start position:0% +have heard input layer then sequence of + + + align:start position:0% +have heard input layer then sequence of +stages purely feed-forward and at least + + align:start position:0% +stages purely feed-forward and at least + + + align:start position:0% +stages purely feed-forward and at least +the canonical leading leading network is + + align:start position:0% +the canonical leading leading network is + + + align:start position:0% +the canonical leading leading network is +one that the output layer has object + + align:start position:0% +one that the output layer has object + + + align:start position:0% +one that the output layer has object +recognition object classification task + + align:start position:0% +recognition object classification task + + + align:start position:0% +recognition object classification task +and the whole network is studied by back + + align:start position:0% +and the whole network is studied by back + + + align:start position:0% +and the whole network is studied by back +prop and supervised learning for that + + align:start position:0% +prop and supervised learning for that + + + align:start position:0% +prop and supervised learning for that +what I'll talk about is the more in in + + align:start position:0% +what I'll talk about is the more in in + + + align:start position:0% +what I'll talk about is the more in in +the spirit of the idea that the first + + align:start position:0% +the spirit of the idea that the first + + + align:start position:0% +the spirit of the idea that the first +stages are more general-purpose than the + + align:start position:0% +stages are more general-purpose than the + + + align:start position:0% +stages are more general-purpose than the +specific a classic task in the output + + align:start position:0% +specific a classic task in the output + + + align:start position:0% +specific a classic task in the output +layer okay so there are many issues + + align:start position:0% +layer okay so there are many issues + + + align:start position:0% +layer okay so there are many issues +number of stages that are require the + + align:start position:0% +number of stages that are require the + + + align:start position:0% +number of stages that are require the +size of them why compression or + + align:start position:0% +size of them why compression or + + + align:start position:0% +size of them why compression or +expansion in many system you see that + + align:start position:0% +expansion in many system you see that + + + align:start position:0% +expansion in many system you see that +the fraction + + align:start position:0% +the fraction + + + align:start position:0% +the fraction +of active neurons is is small in the + + align:start position:0% +of active neurons is is small in the + + + align:start position:0% +of active neurons is is small in the +expanded layer that's what we call + + align:start position:0% +expanded layer that's what we call + + + align:start position:0% +expanded layer that's what we call +sparseness so high sparseness means + + align:start position:0% +sparseness so high sparseness means + + + align:start position:0% +sparseness so high sparseness means +small number of neurons activate any + + align:start position:0% +small number of neurons activate any + + + align:start position:0% +small number of neurons activate any +given stimulus + + align:start position:0% +given stimulus + + + align:start position:0% +given stimulus +it's just terminologies somewhat + + align:start position:0% +it's just terminologies somewhat + + + align:start position:0% +it's just terminologies somewhat +confusing so highs partners is small + + align:start position:0% +confusing so highs partners is small + + + align:start position:0% +confusing so highs partners is small +number of active neurons one important + + align:start position:0% +number of active neurons one important + + + align:start position:0% +number of active neurons one important +and crucial questions is how to + + align:start position:0% +and crucial questions is how to + + + align:start position:0% +and crucial questions is how to +transform what are the filters the + + align:start position:0% +transform what are the filters the + + + align:start position:0% +transform what are the filters the +weights that are good for transforming + + align:start position:0% +weights that are good for transforming + + + align:start position:0% +weights that are good for transforming +sensor information from one layer to + + align:start position:0% +sensor information from one layer to + + + align:start position:0% +sensor information from one layer to +another and in particular whether random + + align:start position:0% +another and in particular whether random + + + align:start position:0% +another and in particular whether random +weights is good enough or maybe even + + align:start position:0% +weights is good enough or maybe even + + + align:start position:0% +weights is good enough or maybe even +even optimal in some sense or all one + + align:start position:0% +even optimal in some sense or all one + + + align:start position:0% +even optimal in some sense or all one +needs most structure the more learned a + + align:start position:0% +needs most structure the more learned a + + + align:start position:0% +needs most structure the more learned a +type of synaptic wave this is a crucial + + align:start position:0% +type of synaptic wave this is a crucial + + + align:start position:0% +type of synaptic wave this is a crucial +question perhaps not for machine + + align:start position:0% +question perhaps not for machine + + + align:start position:0% +question perhaps not for machine +learning but for computational science + + align:start position:0% +learning but for computational science + + + align:start position:0% +learning but for computational science +because there is some experimental + + align:start position:0% +because there is some experimental + + + align:start position:0% +because there is some experimental +evidence for at least of some of the + + align:start position:0% +evidence for at least of some of the + + + align:start position:0% +evidence for at least of some of the +systems that are that are studied that + + align:start position:0% +systems that are that are studied that + + + align:start position:0% +systems that are that are studied that +the mapping from the compressed original + + align:start position:0% +the mapping from the compressed original + + + align:start position:0% +the mapping from the compressed original +representation to the space + + align:start position:0% +representation to the space + + + align:start position:0% +representation to the space +representation is is actually done by + + align:start position:0% +representation is is actually done by + + + align:start position:0% +representation is is actually done by +randomly connected weight so one example + + align:start position:0% +randomly connected weight so one example + + + align:start position:0% +randomly connected weight so one example +is all facto a cortex the mapping from + + align:start position:0% +is all facto a cortex the mapping from + + + align:start position:0% +is all facto a cortex the mapping from +of a factory representation from the + + align:start position:0% +of a factory representation from the + + + align:start position:0% +of a factory representation from the +olfactory bulb so come gloom ever lose + + align:start position:0% +olfactory bulb so come gloom ever lose + + + align:start position:0% +olfactory bulb so come gloom ever lose +layer to the period from cortex seems to + + align:start position:0% +layer to the period from cortex seems to + + + align:start position:0% +layer to the period from cortex seems to +be random as far as one can say + + align:start position:0% +be random as far as one can say + + + align:start position:0% +be random as far as one can say +similarly in the cerebellum the example + + align:start position:0% +similarly in the cerebellum the example + + + align:start position:0% +similarly in the cerebellum the example +that I mentioned before when one looks + + align:start position:0% +that I mentioned before when one looks + + + align:start position:0% +that I mentioned before when one looks +at the mapping from the mossy fiber to + + align:start position:0% +at the mapping from the mossy fiber to + + + align:start position:0% +at the mapping from the mossy fiber to +the granule cell again enormous + + align:start position:0% +the granule cell again enormous + + + align:start position:0% +the granule cell again enormous +expansion by a few orders of magnitude + + align:start position:0% +expansion by a few orders of magnitude + + + align:start position:0% +expansion by a few orders of magnitude +nevertheless it they seem to be random + + align:start position:0% +nevertheless it they seem to be random + + + align:start position:0% +nevertheless it they seem to be random +now of course one cannot say exclude + + align:start position:0% +now of course one cannot say exclude + + + align:start position:0% +now of course one cannot say exclude +exclusively that they're random they're + + align:start position:0% +exclusively that they're random they're + + + align:start position:0% +exclusively that they're random they're +not subtle correlations or structures + + align:start position:0% +not subtle correlations or structures + + + align:start position:0% +not subtle correlations or structures +but nevertheless there is a strong + + align:start position:0% +but nevertheless there is a strong + + + align:start position:0% +but nevertheless there is a strong +motivation to ask whether random + + align:start position:0% +motivation to ask whether random + + + align:start position:0% +motivation to ask whether random +projections are good enough and if not + + align:start position:0% +projections are good enough and if not + + + align:start position:0% +projections are good enough and if not +what does it mean structure what kind of + + align:start position:0% +what does it mean structure what kind of + + + align:start position:0% +what does it mean structure what kind of +what kind of structure is + + align:start position:0% +what kind of structure is + + + align:start position:0% +what kind of structure is +is appropriate for this task question of + + align:start position:0% +is appropriate for this task question of + + + align:start position:0% +is appropriate for this task question of +top-down and feedback loops recurrent + + align:start position:0% +top-down and feedback loops recurrent + + + align:start position:0% +top-down and feedback loops recurrent +connections and so on so that all I hope + + align:start position:0% +connections and so on so that all I hope + + + align:start position:0% +connections and so on so that all I hope +to at least briefly mention later on my + + align:start position:0% +to at least briefly mention later on my + + + align:start position:0% +to at least briefly mention later on my +talk okay so before I continue most of + + align:start position:0% +talk okay so before I continue most of + + + align:start position:0% +talk okay so before I continue most of +our large part of my work of the of the + + align:start position:0% +our large part of my work of the of the + + + align:start position:0% +our large part of my work of the of the +talk will be based on published and + + align:start position:0% +talk will be based on published and + + + align:start position:0% +talk will be based on published and +unpublished work with dr. Abadi who was + + align:start position:0% +unpublished work with dr. Abadi who was + + + align:start position:0% +unpublished work with dr. Abadi who was +until recently a postdoctoral a sports + + align:start position:0% +until recently a postdoctoral a sports + + + align:start position:0% +until recently a postdoctoral a sports +fellow at Harvard University when to do + + align:start position:0% +fellow at Harvard University when to do + + + align:start position:0% +fellow at Harvard University when to do +practice medicine any a Franklin master + + align:start position:0% +practice medicine any a Franklin master + + + align:start position:0% +practice medicine any a Franklin master +student at Hebrew University so you know + + align:start position:0% +student at Hebrew University so you know + + + align:start position:0% +student at Hebrew University so you know +who all you know here or at Harvard or + + align:start position:0% +who all you know here or at Harvard or + + + align:start position:0% +who all you know here or at Harvard or +Akoni PhD student at Hebrew University + + align:start position:0% +Akoni PhD student at Hebrew University + + + align:start position:0% +Akoni PhD student at Hebrew University +and and then we from Penn University + + align:start position:0% +and and then we from Penn University + + + align:start position:0% +and and then we from Penn University +okay so here is our formalization of the + + align:start position:0% +okay so here is our formalization of the + + + align:start position:0% +okay so here is our formalization of the +problem we have an input layer the note + + align:start position:0% +problem we have an input layer the note + + + align:start position:0% +problem we have an input layer the note +is 0 typically it's it's a it's a small + + align:start position:0% +is 0 typically it's it's a it's a small + + + align:start position:0% +is 0 typically it's it's a it's a small +it's a compressed layer with dense + + align:start position:0% +it's a compressed layer with dense + + + align:start position:0% +it's a compressed layer with dense +representation so here every input will + + align:start position:0% +representation so here every input will + + + align:start position:0% +representation so here every input will +generate maybe half of the population on + + align:start position:0% +generate maybe half of the population on + + + align:start position:0% +generate maybe half of the population on +average then there is a feed-forward + + align:start position:0% +average then there is a feed-forward + + + align:start position:0% +average then there is a feed-forward +layer of synaptic weights which expand + + align:start position:0% +layer of synaptic weights which expand + + + align:start position:0% +layer of synaptic weights which expand +to a higher dimension layer which we + + align:start position:0% +to a higher dimension layer which we + + + align:start position:0% +to a higher dimension layer which we +call cortical layer it's expanded in + + align:start position:0% +call cortical layer it's expanded in + + + align:start position:0% +call cortical layer it's expanded in +terms of the number of neurons so this + + align:start position:0% +terms of the number of neurons so this + + + align:start position:0% +terms of the number of neurons so this +will be s 1 it is fast because the F the + + align:start position:0% +will be s 1 it is fast because the F the + + + align:start position:0% +will be s 1 it is fast because the F the +fraction of neurons that are active for + + align:start position:0% +fraction of neurons that are active for + + + align:start position:0% +fraction of neurons that are active for +each given input vector will be small so + + align:start position:0% +each given input vector will be small so + + + align:start position:0% +each given input vector will be small so +it is expanded and spouse that was the + + align:start position:0% +it is expanded and spouse that was the + + + align:start position:0% +it is expanded and spouse that was the +that will be the first part of my talk + + align:start position:0% +that will be the first part of my talk + + + align:start position:0% +that will be the first part of my talk +discussing this then a later on I'll + + align:start position:0% +discussing this then a later on I'll + + + align:start position:0% +discussing this then a later on I'll +talk about staging cascading this + + align:start position:0% +talk about staging cascading this + + + align:start position:0% +talk about staging cascading this +transformation to several stages and + + align:start position:0% +transformation to several stages and + + + align:start position:0% +transformation to several stages and +ultimately there is a readout will be + + align:start position:0% +ultimately there is a readout will be + + + align:start position:0% +ultimately there is a readout will be +some classification task our one will be + + align:start position:0% +some classification task our one will be + + + align:start position:0% +some classification task our one will be +one classification our two will be + + align:start position:0% +one classification our two will be + + + align:start position:0% +one classification our two will be +another classification rule etc each one + + align:start position:0% +another classification rule etc each one + + + align:start position:0% +another classification rule etc each one +of them with synaptic weight which I'll + + align:start position:0% +of them with synaptic weight which I'll + + + align:start position:0% +of them with synaptic weight which I'll +learn + + align:start position:0% +learn + + + align:start position:0% +learn +perform that task okay so that's so we + + align:start position:0% +perform that task okay so that's so we + + + align:start position:0% +perform that task okay so that's so we +call that a supervised layer and that's + + align:start position:0% +call that a supervised layer and that's + + + align:start position:0% +call that a supervised layer and that's +the unsupervised layer okay so that's a + + align:start position:0% +the unsupervised layer okay so that's a + + + align:start position:0% +the unsupervised layer okay so that's a +formalization of the problem and as you + + align:start position:0% +formalization of the problem and as you + + + align:start position:0% +formalization of the problem and as you +will see we'll make enormous Lea + + align:start position:0% +will see we'll make enormous Lea + + + align:start position:0% +will see we'll make enormous Lea +simplifying abstraction of the real + + align:start position:0% +simplifying abstraction of the real + + + align:start position:0% +simplifying abstraction of the real +biological system in order to try to + + align:start position:0% +biological system in order to try to + + + align:start position:0% +biological system in order to try to +gain some insight about the + + align:start position:0% +gain some insight about the + + + align:start position:0% +gain some insight about the +computational capacity of such systems + + align:start position:0% +computational capacity of such systems + + + align:start position:0% +computational capacity of such systems +okay so the first important question is + + align:start position:0% +okay so the first important question is + + + align:start position:0% +okay so the first important question is +what is the statistics the statistical + + align:start position:0% +what is the statistics the statistical + + + align:start position:0% +what is the statistics the statistical +structure of the input so the input is + + align:start position:0% +structure of the input so the input is + + + align:start position:0% +structure of the input so the input is +kind of n dimensional vector n or n 0 + + align:start position:0% +kind of n dimensional vector n or n 0 + + + align:start position:0% +kind of n dimensional vector n or n 0 +when n is the number of units here + + align:start position:0% +when n is the number of units here + + + align:start position:0% +when n is the number of units here +so each sense of event evokes a pattern + + align:start position:0% +so each sense of event evokes a pattern + + + align:start position:0% +so each sense of event evokes a pattern +of activity here but what is the + + align:start position:0% +of activity here but what is the + + + align:start position:0% +of activity here but what is the +structure that the statistical structure + + align:start position:0% +structure that the statistical structure + + + align:start position:0% +structure that the statistical structure +that we are working with and the + + align:start position:0% +that we are working with and the + + + align:start position:0% +that we are working with and the +simplest one to that we are going to + + align:start position:0% +simplest one to that we are going to + + + align:start position:0% +simplest one to that we are going to +discuss is the following so we assume + + align:start position:0% +discuss is the following so we assume + + + align:start position:0% +discuss is the following so we assume +basically that the input are coming from + + align:start position:0% +basically that the input are coming from + + + align:start position:0% +basically that the input are coming from +a mixture of so to speak a mixture of + + align:start position:0% +a mixture of so to speak a mixture of + + + align:start position:0% +a mixture of so to speak a mixture of +Gaussian statistics it's not going to be + + align:start position:0% +Gaussian statistics it's not going to be + + + align:start position:0% +Gaussian statistics it's not going to be +Gaussian because for simplicity we'll + + align:start position:0% +Gaussian because for simplicity we'll + + + align:start position:0% +Gaussian because for simplicity we'll +assume they're binary but this doesn't + + align:start position:0% +assume they're binary but this doesn't + + + align:start position:0% +assume they're binary but this doesn't +matter actually so imagine that this is + + align:start position:0% +matter actually so imagine that this is + + + align:start position:0% +matter actually so imagine that this is +kind of a graphical representation at or + + align:start position:0% +kind of a graphical representation at or + + + align:start position:0% +kind of a graphical representation at or +of high dimensional space and imagine + + align:start position:0% +of high dimensional space and imagine + + + align:start position:0% +of high dimensional space and imagine +each in the inputs the sensory inputs + + align:start position:0% +each in the inputs the sensory inputs + + + align:start position:0% +each in the inputs the sensory inputs +imagine that there are a clustered + + align:start position:0% +imagine that there are a clustered + + + align:start position:0% +imagine that there are a clustered +around templates or cluster centers in + + align:start position:0% +around templates or cluster centers in + + + align:start position:0% +around templates or cluster centers in +so this would be the centers of this of + + align:start position:0% +so this would be the centers of this of + + + align:start position:0% +so this would be the centers of this of +these balls and the the input itself is + + align:start position:0% +these balls and the the input itself is + + + align:start position:0% +these balls and the the input itself is +coming from the neighborhoods of those + + align:start position:0% +coming from the neighborhoods of those + + + align:start position:0% +coming from the neighborhoods of those +templates so each input will be one + + align:start position:0% +templates so each input will be one + + + align:start position:0% +templates so each input will be one +point in this in this space and it will + + align:start position:0% +point in this in this space and it will + + + align:start position:0% +point in this in this space and it will +be originating from one of those and + + align:start position:0% +be originating from one of those and + + + align:start position:0% +be originating from one of those and +some of one of those states so that's a + + align:start position:0% +some of one of those states so that's a + + + align:start position:0% +some of one of those states so that's a +simple simple architecture and we are + + align:start position:0% +simple simple architecture and we are + + + align:start position:0% +simple simple architecture and we are +going so in in real space nothing it + + align:start position:0% +going so in in real space nothing it + + + align:start position:0% +going so in in real space nothing it +will be mapping from one of those states + + align:start position:0% +will be mapping from one of those states + + + align:start position:0% +will be mapping from one of those states +into another state in the next layer and + + align:start position:0% +into another state in the next layer and + + + align:start position:0% +into another state in the next layer and +then and then finally the + + align:start position:0% +then and then finally the + + + align:start position:0% +then and then finally the +tasks will be to take imagine that some + + align:start position:0% +tasks will be to take imagine that some + + + align:start position:0% +tasks will be to take imagine that some +of those balls are classified as plus + + align:start position:0% +of those balls are classified as plus + + + align:start position:0% +of those balls are classified as plus +let's say though the olfactory stimuli + + align:start position:0% +let's say though the olfactory stimuli + + + align:start position:0% +let's say though the olfactory stimuli +and some of them are classified as a + + align:start position:0% +and some of them are classified as a + + + align:start position:0% +and some of them are classified as a +appetitive some of them as aversive so + + align:start position:0% +appetitive some of them as aversive so + + + align:start position:0% +appetitive some of them as aversive so +the output layer the the readout unit + + align:start position:0% +the output layer the the readout unit + + + align:start position:0% +the output layer the the readout unit +has to classify some of those spheres as + + align:start position:0% +has to classify some of those spheres as + + + align:start position:0% +has to classify some of those spheres as +a class and some of them are - and of + + align:start position:0% +a class and some of them are - and of + + + align:start position:0% +a class and some of them are - and of +course depending on the how many of them + + align:start position:0% +course depending on the how many of them + + + align:start position:0% +course depending on the how many of them +are any dimensionality and their + + align:start position:0% +are any dimensionality and their + + + align:start position:0% +are any dimensionality and their +location this may or may not be an easy + + align:start position:0% +location this may or may not be an easy + + + align:start position:0% +location this may or may not be an easy +problem so for instance here here it's + + align:start position:0% +problem so for instance here here it's + + + align:start position:0% +problem so for instance here here it's +fine there is a linear classifier on the + + align:start position:0% +fine there is a linear classifier on the + + + align:start position:0% +fine there is a linear classifier on the +input space can do it here + + align:start position:0% +input space can do it here + + + align:start position:0% +input space can do it here +I think that should be some mistakes in + + align:start position:0% +I think that should be some mistakes in + + + align:start position:0% +I think that should be some mistakes in +yeah yeah + + align:start position:0% +yeah yeah + + + align:start position:0% +yeah yeah +so here is in a case where the the + + align:start position:0% +so here is in a case where the the + + + align:start position:0% +so here is in a case where the the +linear classifier at the input layer + + align:start position:0% +linear classifier at the input layer + + + align:start position:0% +linear classifier at the input layer +cannot do it and that's our debts and + + align:start position:0% +cannot do it and that's our debts and + + + align:start position:0% +cannot do it and that's our debts and +that's a theme which is very popular + + align:start position:0% +that's a theme which is very popular + + + align:start position:0% +that's a theme which is very popular +both in computational science in and + + align:start position:0% +both in computational science in and + + + align:start position:0% +both in computational science in and +system neuroscience studies in machine + + align:start position:0% +system neuroscience studies in machine + + + align:start position:0% +system neuroscience studies in machine +learning and the following the following + + align:start position:0% +learning and the following the following + + + align:start position:0% +learning and the following the following +question comes up suppose we see that + + align:start position:0% +question comes up suppose we see that + + + align:start position:0% +question comes up suppose we see that +there is a transformation of data from + + align:start position:0% +there is a transformation of data from + + + align:start position:0% +there is a transformation of data from +let's a photo photoreceptor layer in + + align:start position:0% +let's a photo photoreceptor layer in + + + align:start position:0% +let's a photo photoreceptor layer in +vision to the ganglion cells at the + + align:start position:0% +vision to the ganglion cells at the + + + align:start position:0% +vision to the ganglion cells at the +output of the retina then to cortex and + + align:start position:0% +output of the retina then to cortex and + + + align:start position:0% +output of the retina then to cortex and +in several stages how do we gauge how do + + align:start position:0% +in several stages how do we gauge how do + + + align:start position:0% +in several stages how do we gauge how do +we assess what is the what is the + + align:start position:0% +we assess what is the what is the + + + align:start position:0% +we assess what is the what is the +advantage for the brain to transform + + align:start position:0% +advantage for the brain to transform + + + align:start position:0% +advantage for the brain to transform +information from one let's say from + + align:start position:0% +information from one let's say from + + + align:start position:0% +information from one let's say from +retina to v1 and so on so forth + + align:start position:0% +retina to v1 and so on so forth + + + align:start position:0% +retina to v1 and so on so forth +basically after all in this feed forward + + align:start position:0% +basically after all in this feed forward + + + align:start position:0% +basically after all in this feed forward +architecture no net information is + + align:start position:0% +architecture no net information is + + + align:start position:0% +architecture no net information is +generated at the next layer so if known + + align:start position:0% +generated at the next layer so if known + + + align:start position:0% +generated at the next layer so if known +if not information is generated the + + align:start position:0% +if not information is generated the + + + align:start position:0% +if not information is generated the +question is what + + align:start position:0% +question is what + + + align:start position:0% +question is what +what did we gain by these + + align:start position:0% +what did we gain by these + + + align:start position:0% +what did we gain by these +transformations and one one possible + + align:start position:0% +transformations and one one possible + + + align:start position:0% +transformations and one one possible +answer is that it is reformatted we live + + align:start position:0% +answer is that it is reformatted we live + + + align:start position:0% +answer is that it is reformatted we live +formatting the sensory representation in + + align:start position:0% +formatting the sensory representation in + + + align:start position:0% +formatting the sensory representation in +two different representation which will + + align:start position:0% +two different representation which will + + + align:start position:0% +two different representation which will +make subsequent computations simpler so + + align:start position:0% +make subsequent computations simpler so + + + align:start position:0% +make subsequent computations simpler so +what does it mean subset computation + + align:start position:0% +what does it mean subset computation + + + align:start position:0% +what does it mean subset computation +subsequent computations simpler one + + align:start position:0% +subsequent computations simpler one + + + align:start position:0% +subsequent computations simpler one +notion of simplicity is whether + + align:start position:0% +notion of simplicity is whether + + + align:start position:0% +notion of simplicity is whether +subsequent computation can be realized + + align:start position:0% +subsequent computation can be realized + + + align:start position:0% +subsequent computation can be realized +by a simple linear linear readout so + + align:start position:0% +by a simple linear linear readout so + + + align:start position:0% +by a simple linear linear readout so +that's that's the that's the strategy + + align:start position:0% +that's that's the that's the strategy + + + align:start position:0% +that's that's the that's the strategy +that we are going to to adopt here and + + align:start position:0% +that we are going to to adopt here and + + + align:start position:0% +that we are going to to adopt here and +this is to ask as the information as the + + align:start position:0% +this is to ask as the information as the + + + align:start position:0% +this is to ask as the information as the +representation is changing as you go + + align:start position:0% +representation is changing as you go + + + align:start position:0% +representation is changing as you go +from one layer to another how well a + + align:start position:0% +from one layer to another how well a + + + align:start position:0% +from one layer to another how well a +linear readout will be able to perform + + align:start position:0% +linear readout will be able to perform + + + align:start position:0% +linear readout will be able to perform +the task okay so that's the input that's + + align:start position:0% +the task okay so that's the input that's + + + align:start position:0% +the task okay so that's the input that's +the story and another said there is an + + align:start position:0% +the story and another said there is an + + + align:start position:0% +the story and another said there is an +input unsupervised representations and + + align:start position:0% +input unsupervised representations and + + + align:start position:0% +input unsupervised representations and +supervised at the end okay okay now I + + align:start position:0% +supervised at the end okay okay now I + + + align:start position:0% +supervised at the end okay okay now I +mean I need to put two into those + + align:start position:0% +mean I need to put two into those + + + align:start position:0% +mean I need to put two into those +notations bear with me this is a + + align:start position:0% +notations bear with me this is a + + + align:start position:0% +notations bear with me this is a +computational talk I cannot just talk + + align:start position:0% +computational talk I cannot just talk + + + align:start position:0% +computational talk I cannot just talk +about ideas because the the whole thing + + align:start position:0% +about ideas because the the whole thing + + + align:start position:0% +about ideas because the the whole thing +is to be able to actually come up with a + + align:start position:0% +is to be able to actually come up with a + + + align:start position:0% +is to be able to actually come up with a +quantitative theory that test ideas so + + align:start position:0% +quantitative theory that test ideas so + + + align:start position:0% +quantitative theory that test ideas so +let me let me introduce notations so at + + align:start position:0% +let me let me introduce notations so at + + + align:start position:0% +let me let me introduce notations so at +the the centers at each layer you can + + align:start position:0% +the the centers at each layer you can + + + align:start position:0% +the the centers at each layer you can +ask what is the representation of the + + align:start position:0% +ask what is the representation of the + + + align:start position:0% +ask what is the representation of the +centers of this stimuli and I'll denote + + align:start position:0% +centers of this stimuli and I'll denote + + + align:start position:0% +centers of this stimuli and I'll denote +the center by a bar okay and me U is one + + align:start position:0% +the center by a bar okay and me U is one + + + align:start position:0% +the center by a bar okay and me U is one +mu is index of the patterns some u goes + + align:start position:0% +mu is index of the patterns some u goes + + + align:start position:0% +mu is index of the patterns some u goes +from 1 to P P is the number of those + + align:start position:0% +from 1 to P P is the number of those + + + align:start position:0% +from 1 to P P is the number of those +balls number of those fields or number + + align:start position:0% +balls number of those fields or number + + + align:start position:0% +balls number of those fields or number +of those clusters if you think about + + align:start position:0% +of those clusters if you think about + + + align:start position:0% +of those clusters if you think about +clustering some sensory data so P will + + align:start position:0% +clustering some sensory data so P will + + + align:start position:0% +clustering some sensory data so P will +be the number of clusters I from 1 to n + + align:start position:0% +be the number of clusters I from 1 to n + + + align:start position:0% +be the number of clusters I from 1 to n +is simply the neuron of the unit + + align:start position:0% +is simply the neuron of the unit + + + align:start position:0% +is simply the neuron of the unit +activation its mu and n is the layer so + + align:start position:0% +activation its mu and n is the layer so + + + align:start position:0% +activation its mu and n is the layer so +0 is the input layer that's up to Lal ok + + align:start position:0% +0 is the input layer that's up to Lal ok + + + align:start position:0% +0 is the input layer that's up to Lal ok +so this would be 0 1 the mean activation + + align:start position:0% +so this would be 0 1 the mean activation + + + align:start position:0% +so this would be 0 1 the mean activation +at each + + align:start position:0% +at each + + + align:start position:0% +at each +lair from from one on will just kept to + + align:start position:0% +lair from from one on will just kept to + + + align:start position:0% +lair from from one on will just kept to +be constant two BFF goes from zero to + + align:start position:0% +be constant two BFF goes from zero to + + + align:start position:0% +be constant two BFF goes from zero to +one the smaller F is the sponsor the + + align:start position:0% +one the smaller F is the sponsor the + + + align:start position:0% +one the smaller F is the sponsor the +representation is we will assume that + + align:start position:0% +representation is we will assume that + + + align:start position:0% +representation is we will assume that +the input representation is dense of + + align:start position:0% +the input representation is dense of + + + align:start position:0% +the input representation is dense of +this is 0.5 and again will assume to be + + align:start position:0% +this is 0.5 and again will assume to be + + + align:start position:0% +this is 0.5 and again will assume to be +constant PCT constant across layer + + align:start position:0% +constant PCT constant across layer + + + align:start position:0% +constant PCT constant across layer +except for the first level there is + + align:start position:0% +except for the first level there is + + + align:start position:0% +except for the first level there is +expansion + + align:start position:0% +expansion + + + align:start position:0% +expansion +you can vary those parameters and + + align:start position:0% +you can vary those parameters and + + + align:start position:0% +you can vary those parameters and +actually the theory accommodates + + align:start position:0% +actually the theory accommodates + + + align:start position:0% +actually the theory accommodates +variations of those but that's the + + align:start position:0% +variations of those but that's the + + + align:start position:0% +variations of those but that's the +simplest architecture you expand and + + align:start position:0% +simplest architecture you expand and + + + align:start position:0% +simplest architecture you expand and +dense representation into a sparse + + align:start position:0% +dense representation into a sparse + + + align:start position:0% +dense representation into a sparse +higher dimension and you keep doing it + + align:start position:0% +higher dimension and you keep doing it + + + align:start position:0% +higher dimension and you keep doing it +as you go along okay so that's notation + + align:start position:0% +as you go along okay so that's notation + + + align:start position:0% +as you go along okay so that's notation +okay now I how do how do we assess what + + align:start position:0% +okay now I how do how do we assess what + + + align:start position:0% +okay now I how do how do we assess what +is what is the next stage is doing to + + align:start position:0% +is what is the next stage is doing to + + + align:start position:0% +is what is the next stage is doing to +those clusters okay so as I said one + + align:start position:0% +those clusters okay so as I said one + + + align:start position:0% +those clusters okay so as I said one +measure is take a linear classifier and + + align:start position:0% +measure is take a linear classifier and + + + align:start position:0% +measure is take a linear classifier and +see how Lin a classifier performs okay + + align:start position:0% +see how Lin a classifier performs okay + + + align:start position:0% +see how Lin a classifier performs okay +but actually you can you can also look + + align:start position:0% +but actually you can you can also look + + + align:start position:0% +but actually you can you can also look +at the statistics of the injected + + align:start position:0% +at the statistics of the injected + + + align:start position:0% +at the statistics of the injected +sensory stimuli at each layer and learn + + align:start position:0% +sensory stimuli at each layer and learn + + + align:start position:0% +sensory stimuli at each layer and learn +something from it and basically I'm + + align:start position:0% +something from it and basically I'm + + + align:start position:0% +something from it and basically I'm +going to suggest looking at the two + + align:start position:0% +going to suggest looking at the two + + + align:start position:0% +going to suggest looking at the two +major statistical aspects of the data as + + align:start position:0% +major statistical aspects of the data as + + + align:start position:0% +major statistical aspects of the data as +each layer of the transformation one of + + align:start position:0% +each layer of the transformation one of + + + align:start position:0% +each layer of the transformation one of +them is noise and one of them is + + align:start position:0% +them is noise and one of them is + + + align:start position:0% +them is noise and one of them is +correlation so what is what is noise so + + align:start position:0% +correlation so what is what is noise so + + + align:start position:0% +correlation so what is what is noise so +again noise will be simply the the + + align:start position:0% +again noise will be simply the the + + + align:start position:0% +again noise will be simply the the +radius or measure of the radius of this + + align:start position:0% +radius or measure of the radius of this + + + align:start position:0% +radius or measure of the radius of this +of this field so if you had only the + + align:start position:0% +of this field so if you had only the + + + align:start position:0% +of this field so if you had only the +templates as input the problem would be + + align:start position:0% +templates as input the problem would be + + + align:start position:0% +templates as input the problem would be +simple problem would be easy as long as + + align:start position:0% +simple problem would be easy as long as + + + align:start position:0% +simple problem would be easy as long as +we have enough dimension you expand it + + align:start position:0% +we have enough dimension you expand it + + + align:start position:0% +we have enough dimension you expand it +you can easily do linear classifier and + + align:start position:0% +you can easily do linear classifier and + + + align:start position:0% +you can easily do linear classifier and +an end and solve the problem so the + + align:start position:0% +an end and solve the problem so the + + + align:start position:0% +an end and solve the problem so the +problem in our case is the fact that the + + align:start position:0% +problem in our case is the fact that the + + + align:start position:0% +problem in our case is the fact that the +input is actually the infinite number of + + align:start position:0% +input is actually the infinite number of + + + align:start position:0% +input is actually the infinite number of +inputs or exponentially large number of + + align:start position:0% +inputs or exponentially large number of + + + align:start position:0% +inputs or exponentially large number of +possible inputs because they all come + + align:start position:0% +possible inputs because they all come + + + align:start position:0% +possible inputs because they all come +from + + align:start position:0% +from + + + align:start position:0% +from +from from Gaussian or binarized version + + align:start position:0% +from from Gaussian or binarized version + + + align:start position:0% +from from Gaussian or binarized version +of a Gaussian noise around the templates + + align:start position:0% +of a Gaussian noise around the templates + + + align:start position:0% +of a Gaussian noise around the templates +and at the node the noise by Delta zero + + align:start position:0% +and at the node the noise by Delta zero + + + align:start position:0% +and at the node the noise by Delta zero +means no noise one the normalization is + + align:start position:0% +means no noise one the normalization is + + + align:start position:0% +means no noise one the normalization is +such that one means that they are random + + align:start position:0% +such that one means that they are random + + + align:start position:0% +such that one means that they are random +so Delta equals to one means that + + align:start position:0% +so Delta equals to one means that + + + align:start position:0% +so Delta equals to one means that +basically you cannot tell of the input + + align:start position:0% +basically you cannot tell of the input + + + align:start position:0% +basically you cannot tell of the input +whether it's coming from here or from + + align:start position:0% +whether it's coming from here or from + + + align:start position:0% +whether it's coming from here or from +any other points in the input space the + + align:start position:0% +any other points in the input space the + + + align:start position:0% +any other points in the input space the +other thing is correlations is more + + align:start position:0% +other thing is correlations is more + + + align:start position:0% +other thing is correlations is more +subtle so I'm going to assume that those + + align:start position:0% +subtle so I'm going to assume that those + + + align:start position:0% +subtle so I'm going to assume that those +those balls are coming from kind of + + align:start position:0% +those balls are coming from kind of + + + align:start position:0% +those balls are coming from kind of +uniform distribution imagine you take a + + align:start position:0% +uniform distribution imagine you take a + + + align:start position:0% +uniform distribution imagine you take a +template here you draw a ball around it + + align:start position:0% +template here you draw a ball around it + + + align:start position:0% +template here you draw a ball around it +take a template to draw but everything + + align:start position:0% +take a template to draw but everything + + + align:start position:0% +take a template to draw but everything +is kind of uniform distribution you + + align:start position:0% +is kind of uniform distribution you + + + align:start position:0% +is kind of uniform distribution you +distributed the only structure is the + + align:start position:0% +distributed the only structure is the + + + align:start position:0% +distributed the only structure is the +fact that data comes from this mixture + + align:start position:0% +fact that data comes from this mixture + + + align:start position:0% +fact that data comes from this mixture +of gaussians or noisy patterns around or + + align:start position:0% +of gaussians or noisy patterns around or + + + align:start position:0% +of gaussians or noisy patterns around or +centers okay so that's fine but as you + + align:start position:0% +centers okay so that's fine but as you + + + align:start position:0% +centers okay so that's fine but as you +project project this project those those + + align:start position:0% +project project this project those those + + + align:start position:0% +project project this project those those +clusters into the next stage I claim + + align:start position:0% +clusters into the next stage I claim + + + align:start position:0% +clusters into the next stage I claim +that those centers those templates get + + align:start position:0% +that those centers those templates get + + + align:start position:0% +that those centers those templates get +new representation which can actually + + align:start position:0% +new representation which can actually + + + align:start position:0% +new representation which can actually +have structure in them simply by the + + align:start position:0% +have structure in them simply by the + + + align:start position:0% +have structure in them simply by the +fact that you you you put all of them + + align:start position:0% +fact that you you you put all of them + + + align:start position:0% +fact that you you you put all of them +into this common synaptic weights into + + align:start position:0% +into this common synaptic weights into + + + align:start position:0% +into this common synaptic weights into +the next layer and I'm going to measure + + align:start position:0% +the next layer and I'm going to measure + + + align:start position:0% +the next layer and I'm going to measure +this by hue and basically long q0q is + + align:start position:0% +this by hue and basically long q0q is + + + align:start position:0% +this by hue and basically long q0q is +basically a kind of randomly uniformly + + align:start position:0% +basically a kind of randomly uniformly + + + align:start position:0% +basically a kind of randomly uniformly +distributed centers and I'll always + + align:start position:0% +distributed centers and I'll always + + + align:start position:0% +distributed centers and I'll always +start from that at the input layer but + + align:start position:0% +start from that at the input layer but + + + align:start position:0% +start from that at the input layer but +then there is a danger or it might + + align:start position:0% +then there is a danger or it might + + + align:start position:0% +then there is a danger or it might +happen that as you propagate this + + align:start position:0% +happen that as you propagate this + + + align:start position:0% +happen that as you propagate this +information or this representation to + + align:start position:0% +information or this representation to + + + align:start position:0% +information or this representation to +the next layer the centers will look + + align:start position:0% +the next layer the centers will look + + + align:start position:0% +the next layer the centers will look +like that or older than the data + + align:start position:0% +like that or older than the data + + + align:start position:0% +like that or older than the data +structure data look like that so on + + align:start position:0% +structure data look like that so on + + + align:start position:0% +structure data look like that so on +average you know the distance between + + align:start position:0% +average you know the distance between + + + align:start position:0% +average you know the distance between +two centers on average is the same as + + align:start position:0% +two centers on average is the same as + + + align:start position:0% +two centers on average is the same as +here but they are clumped together it's + + align:start position:0% +here but they are clumped together it's + + + align:start position:0% +here but they are clumped together it's +kind of random clustering of the + + align:start position:0% +kind of random clustering of the + + + align:start position:0% +kind of random clustering of the +clusters and that's + + align:start position:0% +clusters and that's + + + align:start position:0% +clusters and that's +can be induced by the fact that the data + + align:start position:0% +can be induced by the fact that the data + + + align:start position:0% +can be induced by the fact that the data +is feed-forward from and from from this + + align:start position:0% +is feed-forward from and from from this + + + align:start position:0% +is feed-forward from and from from this +representation that can pose a problem + + align:start position:0% +representation that can pose a problem + + + align:start position:0% +representation that can pose a problem +if there is no no is then there is again + + align:start position:0% +if there is no no is then there is again + + + align:start position:0% +if there is no no is then there is again +no no problem you can you can + + align:start position:0% +no no problem you can you can + + + align:start position:0% +no no problem you can you can +differentiate between and so on but if + + align:start position:0% +differentiate between and so on but if + + + align:start position:0% +differentiate between and so on but if +there is noise this can aggravate the + + align:start position:0% +there is noise this can aggravate the + + + align:start position:0% +there is noise this can aggravate the +situation because some of the clusters + + align:start position:0% +situation because some of the clusters + + + align:start position:0% +situation because some of the clusters +become may become dangerously close to + + align:start position:0% +become may become dangerously close to + + + align:start position:0% +become may become dangerously close to +each other and will come to it but + + align:start position:0% +each other and will come to it but + + + align:start position:0% +each other and will come to it but +anyway so we have this Delta the noise + + align:start position:0% +anyway so we have this Delta the noise + + + align:start position:0% +anyway so we have this Delta the noise +the size of the of the clusters and we + + align:start position:0% +the size of the of the clusters and we + + + align:start position:0% +the size of the of the clusters and we +have queued the correlations how they + + align:start position:0% +have queued the correlations how they + + + align:start position:0% +have queued the correlations how they +are clumped into in each representation + + align:start position:0% +are clumped into in each representation + + + align:start position:0% +are clumped into in each representation +and now we can ask how Delta evolved + + align:start position:0% +and now we can ask how Delta evolved + + + align:start position:0% +and now we can ask how Delta evolved +when you go from one representation to + + align:start position:0% +when you go from one representation to + + + align:start position:0% +when you go from one representation to +another how you evolve from one + + align:start position:0% +another how you evolve from one + + + align:start position:0% +another how you evolve from one +representation to another and how linear + + align:start position:0% +representation to another and how linear + + + align:start position:0% +representation to another and how linear +classifier performance will change from + + align:start position:0% +classifier performance will change from + + + align:start position:0% +classifier performance will change from +one representation to another so the + + align:start position:0% +one representation to another so the + + + align:start position:0% +one representation to another so the +simplicity of this of this assumption is + + align:start position:0% +simplicity of this of this assumption is + + + align:start position:0% +simplicity of this of this assumption is +allows for allows for kind of a + + align:start position:0% +allows for allows for kind of a + + + align:start position:0% +allows for allows for kind of a +systematic analytical exploration or + + align:start position:0% +systematic analytical exploration or + + + align:start position:0% +systematic analytical exploration or +study of these ok so ok these are + + align:start position:0% +study of these ok so ok these are + + + align:start position:0% +study of these ok so ok these are +definitions let's go ok so what will be + + align:start position:0% +definitions let's go ok so what will be + + + align:start position:0% +definitions let's go ok so what will be +the ideal situation that this situation + + align:start position:0% +the ideal situation that this situation + + + align:start position:0% +the ideal situation that this situation +would be ok so the ideal situation will + + align:start position:0% +would be ok so the ideal situation will + + + align:start position:0% +would be ok so the ideal situation will +be that I start from some level of noise + + align:start position:0% +be that I start from some level of noise + + + align:start position:0% +be that I start from some level of noise +which is the my Gauss my-my-my-my + + align:start position:0% +which is the my Gauss my-my-my-my + + + align:start position:0% +which is the my Gauss my-my-my-my +spheres at the input layer I may or may + + align:start position:0% +spheres at the input layer I may or may + + + align:start position:0% +spheres at the input layer I may or may +not start from with some correlation the + + align:start position:0% +not start from with some correlation the + + + align:start position:0% +not start from with some correlation the +simplest case would be that I start from + + align:start position:0% +simplest case would be that I start from + + + align:start position:0% +simplest case would be that I start from +randomly distributed center so this + + align:start position:0% +randomly distributed center so this + + + align:start position:0% +randomly distributed center so this +would be zero and the best situation + + align:start position:0% +would be zero and the best situation + + + align:start position:0% +would be zero and the best situation +will be that as I Papa gate the sensory + + align:start position:0% +will be that as I Papa gate the sensory + + + align:start position:0% +will be that as I Papa gate the sensory +stimuli Delta the noise will go to zero + + align:start position:0% +stimuli Delta the noise will go to zero + + + align:start position:0% +stimuli Delta the noise will go to zero +okay as I said if the noise goes to zero + + align:start position:0% +okay as I said if the noise goes to zero + + + align:start position:0% +okay as I said if the noise goes to zero +you are left with basically points and + + align:start position:0% +you are left with basically points and + + + align:start position:0% +you are left with basically points and +those points if there is enough + + align:start position:0% +those points if there is enough + + + align:start position:0% +those points if there is enough +dimensionality those points would be + + align:start position:0% +dimensionality those points would be + + + align:start position:0% +dimensionality those points would be +easily classifiable it also be good + + align:start position:0% +easily classifiable it also be good + + + align:start position:0% +easily classifiable it also be good +since if the noise doesn't go to zero to + + align:start position:0% +since if the noise doesn't go to zero to + + + align:start position:0% +since if the noise doesn't go to zero to +have also kind of uniformly spread + + align:start position:0% +have also kind of uniformly spread + + + align:start position:0% +have also kind of uniformly spread +clusters so it will be good to keep Q to + + align:start position:0% +clusters so it will be good to keep Q to + + + align:start position:0% +clusters so it will be good to keep Q to +be small + + align:start position:0% +be small + + + align:start position:0% +be small +okay okay so let's look at one layer so + + align:start position:0% +okay okay so let's look at one layer so + + + align:start position:0% +okay okay so let's look at one layer so +let's look at just we have the input + + align:start position:0% +let's look at just we have the input + + + align:start position:0% +let's look at just we have the input +layer the output layer here and and the + + align:start position:0% +layer the output layer here and and the + + + align:start position:0% +layer the output layer here and and the +readout the first question is what to + + align:start position:0% +readout the first question is what to + + + align:start position:0% +readout the first question is what to +choose for this input layer so the + + align:start position:0% +choose for this input layer so the + + + align:start position:0% +choose for this input layer so the +simplest answer would be choose random + + align:start position:0% +simplest answer would be choose random + + + align:start position:0% +simplest answer would be choose random +okay so what we do is just take Gaussian + + align:start position:0% +okay so what we do is just take Gaussian + + + align:start position:0% +okay so what we do is just take Gaussian +we just IID Gaussian weights in this + + align:start position:0% +we just IID Gaussian weights in this + + + align:start position:0% +we just IID Gaussian weights in this +layer a very simple with zero mean some + + align:start position:0% +layer a very simple with zero mean some + + + align:start position:0% +layer a very simple with zero mean some +normalization doesn't matter then we + + align:start position:0% +normalization doesn't matter then we + + + align:start position:0% +normalization doesn't matter then we +project them into each one of these guys + + align:start position:0% +project them into each one of these guys + + + align:start position:0% +project them into each one of these guys +here and then we add threshold to + + align:start position:0% +here and then we add threshold to + + + align:start position:0% +here and then we add threshold to +enforce the sparsity that that we that + + align:start position:0% +enforce the sparsity that that we that + + + align:start position:0% +enforce the sparsity that that we that +we want okay so whatever the the + + align:start position:0% +we want okay so whatever the the + + + align:start position:0% +we want okay so whatever the the +activation here is whatever the input is + + align:start position:0% +activation here is whatever the input is + + + align:start position:0% +activation here is whatever the input is +here here is the threshold make sure + + align:start position:0% +here here is the threshold make sure + + + align:start position:0% +here here is the threshold make sure +that only the F the with the largest + + align:start position:0% +that only the F the with the largest + + + align:start position:0% +that only the F the with the largest +input will be active and the rest will + + align:start position:0% +input will be active and the rest will + + + align:start position:0% +input will be active and the rest will +be zero so there is a non-linearity + + align:start position:0% +be zero so there is a non-linearity + + + align:start position:0% +be zero so there is a non-linearity +which is the first extremely important + + align:start position:0% +which is the first extremely important + + + align:start position:0% +which is the first extremely important +if you map one layer to another with a + + align:start position:0% +if you map one layer to another with a + + + align:start position:0% +if you map one layer to another with a +linear a linear transformation you don't + + align:start position:0% +linear a linear transformation you don't + + + align:start position:0% +linear a linear transformation you don't +you don't gain anything in terms of + + align:start position:0% +you don't gain anything in terms of + + + align:start position:0% +you don't gain anything in terms of +classification so there is a + + align:start position:0% +classification so there is a + + + align:start position:0% +classification so there is a +non-linearity simply threshold + + align:start position:0% +non-linearity simply threshold + + + align:start position:0% +non-linearity simply threshold +non-linearity after an input input + + align:start position:0% +non-linearity after an input input + + + align:start position:0% +non-linearity after an input input +projection all right so how we're going + + align:start position:0% +projection all right so how we're going + + + align:start position:0% +projection all right so how we're going +to do this so so it's straightforward to + + align:start position:0% +to do this so so it's straightforward to + + + align:start position:0% +to do this so so it's straightforward to +actually compute analytically what will + + align:start position:0% +actually compute analytically what will + + + align:start position:0% +actually compute analytically what will +happen to a noise so imagine you take + + align:start position:0% +happen to a noise so imagine you take + + + align:start position:0% +happen to a noise so imagine you take +two input vectors with some hanging + + align:start position:0% +two input vectors with some hanging + + + align:start position:0% +two input vectors with some hanging +distance apart from each other you map + + align:start position:0% +distance apart from each other you map + + + align:start position:0% +distance apart from each other you map +them into by by by by convolving them + + align:start position:0% +them into by by by by convolving them + + + align:start position:0% +them into by by by by convolving them +Toto speak with with with the Gaussian + + align:start position:0% +Toto speak with with with the Gaussian + + + align:start position:0% +Toto speak with with with the Gaussian +weight and then threshold in them to get + + align:start position:0% +weight and then threshold in them to get + + + align:start position:0% +weight and then threshold in them to get +some sparsity so every the sparsity the + + align:start position:0% +some sparsity so every the sparsity the + + + align:start position:0% +some sparsity so every the sparsity the +smaller the f is that the sparse on it + + align:start position:0% +smaller the f is that the sparse on it + + + align:start position:0% +smaller the f is that the sparse on it +is so this is the noise level the gun or + + align:start position:0% +is so this is the noise level the gun or + + + align:start position:0% +is so this is the noise level the gun or +malaises Gaussian I'm sorry reduce or + + align:start position:0% +malaises Gaussian I'm sorry reduce or + + + align:start position:0% +malaises Gaussian I'm sorry reduce or +Hamming distance in the in the output + + align:start position:0% +Hamming distance in the in the output + + + align:start position:0% +Hamming distance in the in the output +layer versus the input layer well if + + align:start position:0% +layer versus the input layer well if + + + align:start position:0% +layer versus the input layer well if +zero start then of course you started + + align:start position:0% +zero start then of course you started + + + align:start position:0% +zero start then of course you started +the origin if you are random in the + + align:start position:0% +the origin if you are random in the + + + align:start position:0% +the origin if you are random in the +input will be random there so these + + align:start position:0% +input will be random there so these + + + align:start position:0% +input will be random there so these +points are fine but as you see + + align:start position:0% +points are fine but as you see + + + align:start position:0% +points are fine but as you see +immediately there is an amplification of + + align:start position:0% +immediately there is an amplification of + + + align:start position:0% +immediately there is an amplification of +the noise as you go from from the input + + align:start position:0% +the noise as you go from from the input + + + align:start position:0% +the noise as you go from from the input +to the output right so you start from + + align:start position:0% +to the output right so you start from + + + align:start position:0% +to the output right so you start from +point two but you get actually after one + + align:start position:0% +point two but you get actually after one + + + align:start position:0% +point two but you get actually after one +layer two point six okay and actually + + align:start position:0% +layer two point six okay and actually + + + align:start position:0% +layer two point six okay and actually +for loss for the span silk is so this is + + align:start position:0% +for loss for the span silk is so this is + + + align:start position:0% +for loss for the span silk is so this is +a relatively high sparsity or at least + + align:start position:0% +a relatively high sparsity or at least + + + align:start position:0% +a relatively high sparsity or at least +you go from here to here by increasing + + align:start position:0% +you go from here to here by increasing + + + align:start position:0% +you go from here to here by increasing +sparsity namely f becomes smaller and as + + align:start position:0% +sparsity namely f becomes smaller and as + + + align:start position:0% +sparsity namely f becomes smaller and as +have become smaller this curve is + + align:start position:0% +have become smaller this curve is + + + align:start position:0% +have become smaller this curve is +actually steeper and steeper so not only + + align:start position:0% +actually steeper and steeper so not only + + + align:start position:0% +actually steeper and steeper so not only +you amplify noise but you also the + + align:start position:0% +you amplify noise but you also the + + + align:start position:0% +you amplify noise but you also the +amplification becomes worse thus parcel + + align:start position:0% +amplification becomes worse thus parcel + + + align:start position:0% +amplification becomes worse thus parcel +the representation is so that is the + + align:start position:0% +the representation is so that is the + + + align:start position:0% +the representation is so that is the +kind of negative result the idea that + + align:start position:0% +kind of negative result the idea that + + + align:start position:0% +kind of negative result the idea that +you can gain by expanding data to a + + align:start position:0% +you can gain by expanding data to a + + + align:start position:0% +you can gain by expanding data to a +higher dimension and make them more + + align:start position:0% +higher dimension and make them more + + + align:start position:0% +higher dimension and make them more +separable later on it dates back to + + align:start position:0% +separable later on it dates back to + + + align:start position:0% +separable later on it dates back to +David Mouse classical theory of the + + align:start position:0% +David Mouse classical theory of the + + + align:start position:0% +David Mouse classical theory of the +cerebellum but what we show here is that + + align:start position:0% +cerebellum but what we show here is that + + + align:start position:0% +cerebellum but what we show here is that +if you think not about clean data set of + + align:start position:0% +if you think not about clean data set of + + + align:start position:0% +if you think not about clean data set of +point that you want to separate but you + + align:start position:0% +point that you want to separate but you + + + align:start position:0% +point that you want to separate but you +think about the more realistic case of + + align:start position:0% +think about the more realistic case of + + + align:start position:0% +think about the more realistic case of +you have noisy data or data with high + + align:start position:0% +you have noisy data or data with high + + + align:start position:0% +you have noisy data or data with high +variance then then the situation is very + + align:start position:0% +variance then then the situation is very + + + align:start position:0% +variance then then the situation is very +different so a random expansion is + + align:start position:0% +different so a random expansion is + + + align:start position:0% +different so a random expansion is +actually amplify snows and that's that's + + align:start position:0% +actually amplify snows and that's that's + + + align:start position:0% +actually amplify snows and that's that's +a theme that will actually we will live + + align:start position:0% +a theme that will actually we will live + + + align:start position:0% +a theme that will actually we will live +with it as we go along + + align:start position:0% +with it as we go along + + + align:start position:0% +with it as we go along +random expansion is doing the separation + + align:start position:0% +random expansion is doing the separation + + + align:start position:0% +random expansion is doing the separation +of the of the templates but the problem + + align:start position:0% +of the of the templates but the problem + + + align:start position:0% +of the of the templates but the problem +is it also separates two nearby points + + align:start position:0% +is it also separates two nearby points + + + align:start position:0% +is it also separates two nearby points +within a cluster it also separates them + + align:start position:0% +within a cluster it also separates them + + + align:start position:0% +within a cluster it also separates them +so everything becomes separated from + + align:start position:0% +so everything becomes separated from + + + align:start position:0% +so everything becomes separated from +each other and this is why noise is is + + align:start position:0% +each other and this is why noise is is + + + align:start position:0% +each other and this is why noise is is +amplified now what about the most subtle + + align:start position:0% +amplified now what about the most subtle + + + align:start position:0% +amplified now what about the most subtle +thing which is the kind of overlap + + align:start position:0% +thing which is the kind of overlap + + + align:start position:0% +thing which is the kind of overlap +between the center's so on average the + + align:start position:0% +between the center's so on average the + + + align:start position:0% +between the center's so on average the +center's are as far as part as random + + align:start position:0% +center's are as far as part as random + + + align:start position:0% +center's are as far as part as random +things but if you look not on + + align:start position:0% +things but if you look not on + + + align:start position:0% +things but if you look not on +but you look at the individual pairs you + + align:start position:0% +but you look at the individual pairs you + + + align:start position:0% +but you look at the individual pairs you +see that there is an excess correlation + + align:start position:0% +see that there is an excess correlation + + + align:start position:0% +see that there is an excess correlation +so overlap between them so this is + + align:start position:0% +so overlap between them so this is + + + align:start position:0% +so overlap between them so this is +overlap between the Centers again on + + align:start position:0% +overlap between the Centers again on + + + align:start position:0% +overlap between the Centers again on +average it is zero but the violence is + + align:start position:0% +average it is zero but the violence is + + + align:start position:0% +average it is zero but the violence is +not zero on average it's like random but + + align:start position:0% +not zero on average it's like random but + + + align:start position:0% +not zero on average it's like random but +the valence is different is larger than + + align:start position:0% +the valence is different is larger than + + + align:start position:0% +the valence is different is larger than +range or than random and there is a + + align:start position:0% +range or than random and there is a + + + align:start position:0% +range or than random and there is a +there is an amplification there is a + + align:start position:0% +there is an amplification there is a + + + align:start position:0% +there is an amplification there is a +generation of the of the of the success + + align:start position:0% +generation of the of the of the success + + + align:start position:0% +generation of the of the of the success +overlap although it's it's nicely + + align:start position:0% +overlap although it's it's nicely + + + align:start position:0% +overlap although it's it's nicely +controlled by sparsity so as positive + + align:start position:0% +controlled by sparsity so as positive + + + align:start position:0% +controlled by sparsity so as positive +goes down the dis correlations go down + + align:start position:0% +goes down the dis correlations go down + + + align:start position:0% +goes down the dis correlations go down +okay so that's that's that's not a + + align:start position:0% +okay so that's that's that's not a + + + align:start position:0% +okay so that's that's that's not a +tremendous problem the major problem as + + align:start position:0% +tremendous problem the major problem as + + + align:start position:0% +tremendous problem the major problem as +I said is the noise okay by the way you + + align:start position:0% +I said is the noise okay by the way you + + + align:start position:0% +I said is the noise okay by the way you +can you can you can nicely do an + + align:start position:0% +can you can you can nicely do an + + + align:start position:0% +can you can you can nicely do an +exercise where you generate you look at + + align:start position:0% +exercise where you generate you look at + + + align:start position:0% +exercise where you generate you look at +the this cortical layer representation + + align:start position:0% +the this cortical layer representation + + + align:start position:0% +the this cortical layer representation +and you do as BM or PCA you look at the + + align:start position:0% +and you do as BM or PCA you look at the + + + align:start position:0% +and you do as BM or PCA you look at the +eigen value spectrum so if you if you + + align:start position:0% +eigen value spectrum so if you if you + + + align:start position:0% +eigen value spectrum so if you if you +just look at random spouse points and + + align:start position:0% +just look at random spouse points and + + + align:start position:0% +just look at random spouse points and +you look at the SVD this is the angle + + align:start position:0% +you look at the SVD this is the angle + + + align:start position:0% +you look at the SVD this is the angle +values and number rank rank then that's + + align:start position:0% +values and number rank rank then that's + + + align:start position:0% +values and number rank rank then that's +what you find is the famous mung mung + + align:start position:0% +what you find is the famous mung mung + + + align:start position:0% +what you find is the famous mung mung +gain so a store distribution but in our + + align:start position:0% +gain so a store distribution but in our + + + align:start position:0% +gain so a store distribution but in our +case you see there is an external power + + align:start position:0% +case you see there is an external power + + + align:start position:0% +case you see there is an external power +in this case the input layer is hundred + + align:start position:0% +in this case the input layer is hundred + + + align:start position:0% +in this case the input layer is hundred +so the extra power in the input layer in + + align:start position:0% +so the extra power in the input layer in + + + align:start position:0% +so the extra power in the input layer in +the first input eigenvalue now why is it + + align:start position:0% +the first input eigenvalue now why is it + + + align:start position:0% +the first input eigenvalue now why is it +so so so the the what Hugh is telling us + + align:start position:0% +so so so the the what Hugh is telling us + + + align:start position:0% +so so so the the what Hugh is telling us +what Nancy okay telling us is the + + align:start position:0% +what Nancy okay telling us is the + + + align:start position:0% +what Nancy okay telling us is the +following you take random set of you + + align:start position:0% +following you take random set of you + + + align:start position:0% +following you take random set of you +take a set of random points and you + + align:start position:0% +take a set of random points and you + + + align:start position:0% +take a set of random points and you +project them into higher dimension the + + align:start position:0% +project them into higher dimension the + + + align:start position:0% +project them into higher dimension the +start with hundred dimension and you + + align:start position:0% +start with hundred dimension and you + + + align:start position:0% +start with hundred dimension and you +project and in a thousand dimension on + + align:start position:0% +project and in a thousand dimension on + + + align:start position:0% +project and in a thousand dimension on +average they're random but actually so + + align:start position:0% +average they're random but actually so + + + align:start position:0% +average they're random but actually so +you you would imagine that that that + + align:start position:0% +you you would imagine that that that + + + align:start position:0% +you you would imagine that that that +it's a perfect thing you project them + + align:start position:0% +it's a perfect thing you project them + + + align:start position:0% +it's a perfect thing you project them +with random weights then you'll be + + align:start position:0% +with random weights then you'll be + + + align:start position:0% +with random weights then you'll be +imagine that you just created a set of + + align:start position:0% +imagine that you just created a set of + + + align:start position:0% +imagine that you just created a set of +random points in the expanded + + align:start position:0% +random points in the expanded + + + align:start position:0% +random points in the expanded +mention representation if this was so + + align:start position:0% +mention representation if this was so + + + align:start position:0% +mention representation if this was so +then if you do SVM or PCA on dit on this + + align:start position:0% +then if you do SVM or PCA on dit on this + + + align:start position:0% +then if you do SVM or PCA on dit on this +representation you will find what you + + align:start position:0% +representation you will find what you + + + align:start position:0% +representation you will find what you +expect from PCA of a set of random + + align:start position:0% +expect from PCA of a set of random + + + align:start position:0% +expect from PCA of a set of random +points and this is this one in fact + + align:start position:0% +points and this is this one in fact + + + align:start position:0% +points and this is this one in fact +there is a trace of low dimensionality + + align:start position:0% +there is a trace of low dimensionality + + + align:start position:0% +there is a trace of low dimensionality +in the data okay so so I think that's an + + align:start position:0% +in the data okay so so I think that's an + + + align:start position:0% +in the data okay so so I think that's an +important point which I would like to + + align:start position:0% +important point which I would like to + + + align:start position:0% +important point which I would like to +explain you start from a set of points + + align:start position:0% +explain you start from a set of points + + + align:start position:0% +explain you start from a set of points +if you don't threshold them and you just + + align:start position:0% +if you don't threshold them and you just + + + align:start position:0% +if you don't threshold them and you just +map them into one thousand dimensional + + align:start position:0% +map them into one thousand dimensional + + + align:start position:0% +map them into one thousand dimensional +space those hundred dimensional input + + align:start position:0% +space those hundred dimensional input + + + align:start position:0% +space those hundred dimensional input +will remain higher than 100 dimensional + + align:start position:0% +will remain higher than 100 dimensional + + + align:start position:0% +will remain higher than 100 dimensional +just before ten ten and so on but + + align:start position:0% +just before ten ten and so on but + + + align:start position:0% +just before ten ten and so on but +everything will live in in Han hundred + + align:start position:0% +everything will live in in Han hundred + + + align:start position:0% +everything will live in in Han hundred +dimensional space now you add threshold + + align:start position:0% +dimensional space now you add threshold + + + align:start position:0% +dimensional space now you add threshold +a high threshold being by sparsity so + + align:start position:0% +a high threshold being by sparsity so + + + align:start position:0% +a high threshold being by sparsity so +those 100 dimensional subspace becomes + + align:start position:0% +those 100 dimensional subspace becomes + + + align:start position:0% +those 100 dimensional subspace becomes +now thousand dimensional space because + + align:start position:0% +now thousand dimensional space because + + + align:start position:0% +now thousand dimensional space because +of the non-linearity but but this + + align:start position:0% +of the non-linearity but but this + + + align:start position:0% +of the non-linearity but but this +non-linearity although it takes on the + + align:start position:0% +non-linearity although it takes on the + + + align:start position:0% +non-linearity although it takes on the +dimensional input and makes them + + align:start position:0% +dimensional input and makes them + + + align:start position:0% +dimensional input and makes them +thousand dimensional it's still not like + + align:start position:0% +thousand dimensional it's still not like + + + align:start position:0% +thousand dimensional it's still not like +a random there is still this thousand + + align:start position:0% +a random there is still this thousand + + + align:start position:0% +a random there is still this thousand +dimensional cloud is still elongated + + align:start position:0% +dimensional cloud is still elongated + + + align:start position:0% +dimensional cloud is still elongated +it's not simply uniformly distributed + + align:start position:0% +it's not simply uniformly distributed + + + align:start position:0% +it's not simply uniformly distributed +and that this is the this is the + + align:start position:0% +and that this is the this is the + + + align:start position:0% +and that this is the this is the +signature that you see here in the first + + align:start position:0% +signature that you see here in the first + + + align:start position:0% +signature that you see here in the first +largest hundred eigenvalues there is + + align:start position:0% +largest hundred eigenvalues there is + + + align:start position:0% +largest hundred eigenvalues there is +extra power relative to to to the to the + + align:start position:0% +extra power relative to to to the to the + + + align:start position:0% +extra power relative to to to the to the +random okay the rest is not zero so if + + align:start position:0% +random okay the rest is not zero so if + + + align:start position:0% +random okay the rest is not zero so if +you look here you know this is this goes + + align:start position:0% +you look here you know this is this goes + + + align:start position:0% +you look here you know this is this goes +up to thousand the rest is not zero but + + align:start position:0% +up to thousand the rest is not zero but + + + align:start position:0% +up to thousand the rest is not zero but +so the system is strictly speaking + + align:start position:0% +so the system is strictly speaking + + + align:start position:0% +so the system is strictly speaking +thousand dimensional space but it's not + + align:start position:0% +thousand dimensional space but it's not + + + align:start position:0% +thousand dimensional space but it's not +random it is has increased power in + + align:start position:0% +random it is has increased power in + + + align:start position:0% +random it is has increased power in +hundred channels if you do a read out + + align:start position:0% +hundred channels if you do a read out + + + align:start position:0% +hundred channels if you do a read out +linear classifier read out what you find + + align:start position:0% +linear classifier read out what you find + + + align:start position:0% +linear classifier read out what you find +in this again in when you when you + + align:start position:0% +in this again in when you when you + + + align:start position:0% +in this again in when you when you +expand with a random okay with random + + align:start position:0% +expand with a random okay with random + + + align:start position:0% +expand with a random okay with random +with random weights you find that there + + align:start position:0% +with random weights you find that there + + + align:start position:0% +with random weights you find that there +is an optimal an optimal sparsity so + + align:start position:0% +is an optimal an optimal sparsity so + + + align:start position:0% +is an optimal an optimal sparsity so +this is the readout arrow for a + + align:start position:0% +this is the readout arrow for a + + + align:start position:0% +this is the readout arrow for a +classifier the output is a function of + + align:start position:0% +classifier the output is a function of + + + align:start position:0% +classifier the output is a function of +of the sparsity for different level of + + align:start position:0% +of the sparsity for different level of + + + align:start position:0% +of the sparsity for different level of +noise and you see that in the case of + + align:start position:0% +noise and you see that in the case of + + + align:start position:0% +noise and you see that in the case of +random weights there is a very high very + + align:start position:0% +random weights there is a very high very + + + align:start position:0% +random weights there is a very high very +very high sparsity is bad there is an + + align:start position:0% +very high sparsity is bad there is an + + + align:start position:0% +very high sparsity is bad there is an +optimal sparsity of sparseness and then + + align:start position:0% +optimal sparsity of sparseness and then + + + align:start position:0% +optimal sparsity of sparseness and then +there is a shallow increase in the error + + align:start position:0% +there is a shallow increase in the error + + + align:start position:0% +there is a shallow increase in the error +when you go to a denser representation + + align:start position:0% +when you go to a denser representation + + + align:start position:0% +when you go to a denser representation +one important point which I want to + + align:start position:0% +one important point which I want to + + + align:start position:0% +one important point which I want to +emphasize a coming from the null this + + align:start position:0% +emphasize a coming from the null this + + + align:start position:0% +emphasize a coming from the null this +let me skip equations and this is what + + align:start position:0% +let me skip equations and this is what + + + align:start position:0% +let me skip equations and this is what +you see here the question is can I do + + align:start position:0% +you see here the question is can I do + + + align:start position:0% +you see here the question is can I do +better by further increase the layer so + + align:start position:0% +better by further increase the layer so + + + align:start position:0% +better by further increase the layer so +here I plot the readout error as a + + align:start position:0% +here I plot the readout error as a + + + align:start position:0% +here I plot the readout error as a +function of the size of cortical layer + + align:start position:0% +function of the size of cortical layer + + + align:start position:0% +function of the size of cortical layer +can I do better can I make the if I make + + align:start position:0% +can I do better can I make the if I make + + + align:start position:0% +can I do better can I make the if I make +the kernel dimensionality infinite okay + + align:start position:0% +the kernel dimensionality infinite okay + + + align:start position:0% +the kernel dimensionality infinite okay +can I do better okay well you can do + + align:start position:0% +can I do better okay well you can do + + + align:start position:0% +can I do better okay well you can do +better if you start with zero noise but + + align:start position:0% +better if you start with zero noise but + + + align:start position:0% +better if you start with zero noise but +if you have noisy inputs then basically + + align:start position:0% +if you have noisy inputs then basically + + + align:start position:0% +if you have noisy inputs then basically +the basically the the performance + + align:start position:0% +the basically the the performance + + + align:start position:0% +the basically the the performance +saturates and that's kind of surprising + + align:start position:0% +saturates and that's kind of surprising + + + align:start position:0% +saturates and that's kind of surprising +we we were under the we were expected + + align:start position:0% +we we were under the we were expected + + + align:start position:0% +we we were under the we were expected +that if you go to a larger and larger + + align:start position:0% +that if you go to a larger and larger + + + align:start position:0% +that if you go to a larger and larger +representation eventually the error will + + align:start position:0% +representation eventually the error will + + + align:start position:0% +representation eventually the error will +go to zero but it doesn't go to zero and + + align:start position:0% +go to zero but it doesn't go to zero and + + + align:start position:0% +go to zero but it doesn't go to zero and +that actually happens even for what we + + align:start position:0% +that actually happens even for what we + + + align:start position:0% +that actually happens even for what we +call structured representation and + + align:start position:0% +call structured representation and + + + align:start position:0% +call structured representation and +that's the same for different types of + + align:start position:0% +that's the same for different types of + + + align:start position:0% +that's the same for different types of +Linda with our perceptron pseudoinverse + + align:start position:0% +Linda with our perceptron pseudoinverse + + + align:start position:0% +Linda with our perceptron pseudoinverse +SVM all of them show this situation as + + align:start position:0% +SVM all of them show this situation as + + + align:start position:0% +SVM all of them show this situation as +you increase the size of cortical layer + + align:start position:0% +you increase the size of cortical layer + + + align:start position:0% +you increase the size of cortical layer +and that's one of them a very important + + align:start position:0% +and that's one of them a very important + + + align:start position:0% +and that's one of them a very important +outcome of our study that when you talk + + align:start position:0% +outcome of our study that when you talk + + + align:start position:0% +outcome of our study that when you talk +about noisy inputs you can think about + + align:start position:0% +about noisy inputs you can think about + + + align:start position:0% +about noisy inputs you can think about +it as kind of more generalization tasks + + align:start position:0% +it as kind of more generalization tasks + + + align:start position:0% +it as kind of more generalization tasks +then there is the limit about what you + + align:start position:0% +then there is the limit about what you + + + align:start position:0% +then there is the limit about what you +gain by expanding representation if even + + align:start position:0% +gain by expanding representation if even + + + align:start position:0% +gain by expanding representation if even +if you expand in a nonlinear fashion and + + align:start position:0% +if you expand in a nonlinear fashion and + + + align:start position:0% +if you expand in a nonlinear fashion and +you increase the dimensionality you + + align:start position:0% +you increase the dimensionality you + + + align:start position:0% +you increase the dimensionality you +cannot combat the noise + + align:start position:0% +cannot combat the noise + + + align:start position:0% +cannot combat the noise +at least up to some level beyond some + + align:start position:0% +at least up to some level beyond some + + + align:start position:0% +at least up to some level beyond some +level there is no point of further + + align:start position:0% +level there is no point of further + + + align:start position:0% +level there is no point of further +expansion because basically the arrow + + align:start position:0% +expansion because basically the arrow + + + align:start position:0% +expansion because basically the arrow +saturates okay let me let me since times + + align:start position:0% +saturates okay let me let me since times + + + align:start position:0% +saturates okay let me let me since times +goal goes fast let me talk about the + + align:start position:0% +goal goes fast let me talk about the + + + align:start position:0% +goal goes fast let me talk about the +eternity + + align:start position:0% +eternity + + + align:start position:0% +eternity +so if random weights are not doing so + + align:start position:0% +so if random weights are not doing so + + + align:start position:0% +so if random weights are not doing so +well what are the alternatives that + + align:start position:0% +well what are the alternatives that + + + align:start position:0% +well what are the alternatives that +anything is to do some kind of + + align:start position:0% +anything is to do some kind of + + + align:start position:0% +anything is to do some kind of +unsupervised learning here we are doing + + align:start position:0% +unsupervised learning here we are doing + + + align:start position:0% +unsupervised learning here we are doing +it in a kind of a shortcut of + + align:start position:0% +it in a kind of a shortcut of + + + align:start position:0% +it in a kind of a shortcut of +unsupervised learning okay what is the + + align:start position:0% +unsupervised learning okay what is the + + + align:start position:0% +unsupervised learning okay what is the +shortcut we said the following imagine + + align:start position:0% +shortcut we said the following imagine + + + align:start position:0% +shortcut we said the following imagine +that this layers the learner knows about + + align:start position:0% +that this layers the learner knows about + + + align:start position:0% +that this layers the learner knows about +the representation of the clusters it + + align:start position:0% +the representation of the clusters it + + + align:start position:0% +the representation of the clusters it +doesn't know the labels in other words + + align:start position:0% +doesn't know the labels in other words + + + align:start position:0% +doesn't know the labels in other words +whether those are pluses and those are + + align:start position:0% +whether those are pluses and those are + + + align:start position:0% +whether those are pluses and those are +managers which one are pluses and + + align:start position:0% +managers which one are pluses and + + + align:start position:0% +managers which one are pluses and +minuses but it does know about the + + align:start position:0% +minuses but it does know about the + + + align:start position:0% +minuses but it does know about the +statistical structure of the input and + + align:start position:0% +statistical structure of the input and + + + align:start position:0% +statistical structure of the input and +this is this s s bar these are the + + align:start position:0% +this is this s s bar these are the + + + align:start position:0% +this is this s s bar these are the +Centers okay so we want to encode the + + align:start position:0% +Centers okay so we want to encode the + + + align:start position:0% +Centers okay so we want to encode the +statistical structure of the of this + + align:start position:0% +statistical structure of the of this + + + align:start position:0% +statistical structure of the of this +input in this expansion of the of the + + align:start position:0% +input in this expansion of the of the + + + align:start position:0% +input in this expansion of the of the +weight and the way we do the simplest + + align:start position:0% +weight and the way we do the simplest + + + align:start position:0% +weight and the way we do the simplest +way is the kind of head rule we do the + + align:start position:0% +way is the kind of head rule we do the + + + align:start position:0% +way is the kind of head rule we do the +following we say let's first choose a + + align:start position:0% +following we say let's first choose a + + + align:start position:0% +following we say let's first choose a +recruit or allocate a state a spawn + + align:start position:0% +recruit or allocate a state a spawn + + + align:start position:0% +recruit or allocate a state a spawn +state here randomly chosen to associate + + align:start position:0% +state here randomly chosen to associate + + + align:start position:0% +state here randomly chosen to associate +a to represent each one of the clusters + + align:start position:0% +a to represent each one of the clusters + + + align:start position:0% +a to represent each one of the clusters +so these are the are the randomly chosen + + align:start position:0% +so these are the are the randomly chosen + + + align:start position:0% +so these are the are the randomly chosen +patterns here and then we associate + + align:start position:0% +patterns here and then we associate + + + align:start position:0% +patterns here and then we associate +between those randomly chosen + + align:start position:0% +between those randomly chosen + + + align:start position:0% +between those randomly chosen +representations and in the end the + + align:start position:0% +representations and in the end the + + + align:start position:0% +representations and in the end the +actual Centers of the classes at the + + align:start position:0% +actual Centers of the classes at the + + + align:start position:0% +actual Centers of the classes at the +input so this is s bar and R and then we + + align:start position:0% +input so this is s bar and R and then we + + + align:start position:0% +input so this is s bar and R and then we +do the Association by the simple what's + + align:start position:0% +do the Association by the simple what's + + + align:start position:0% +do the Association by the simple what's +called hey bro so this happy enroll + + align:start position:0% +called hey bro so this happy enroll + + + align:start position:0% +called hey bro so this happy enroll +Associate Justice Center with randomly + + align:start position:0% +Associate Justice Center with randomly + + + align:start position:0% +Associate Justice Center with randomly +assign a state in the in the cortical + + align:start position:0% +assign a state in the in the cortical + + + align:start position:0% +assign a state in the in the cortical +layer in in kind of simple summation + + align:start position:0% +layer in in kind of simple summation + + + align:start position:0% +layer in in kind of simple summation +without the product for the hypodermis + + align:start position:0% +without the product for the hypodermis + + + align:start position:0% +without the product for the hypodermis +sofisticated ways to do it but that's + + align:start position:0% +sofisticated ways to do it but that's + + + align:start position:0% +sofisticated ways to do it but that's +the simplest one of doing so it turns + + align:start position:0% +the simplest one of doing so it turns + + + align:start position:0% +the simplest one of doing so it turns +out that this simple rule is + + align:start position:0% +out that this simple rule is + + + align:start position:0% +out that this simple rule is +has enormous potential for suppressing + + align:start position:0% +has enormous potential for suppressing + + + align:start position:0% +has enormous potential for suppressing +noise so it's again this is the input + + align:start position:0% +noise so it's again this is the input + + + align:start position:0% +noise so it's again this is the input +noise than the output noise the humming + + align:start position:0% +noise than the output noise the humming + + + align:start position:0% +noise than the output noise the humming +this distance of the input and the + + align:start position:0% +this distance of the input and the + + + align:start position:0% +this distance of the input and the +output properly normalized and you see + + align:start position:0% +output properly normalized and you see + + + align:start position:0% +output properly normalized and you see +that as you go to higher and higher + + align:start position:0% +that as you go to higher and higher + + + align:start position:0% +that as you go to higher and higher +sparseness toulon low F this is + + align:start position:0% +sparseness toulon low F this is + + + align:start position:0% +sparseness toulon low F this is +basically the the input noise is + + align:start position:0% +basically the the input noise is + + + align:start position:0% +basically the the input noise is +completely quenched whenever an F is + + align:start position:0% +completely quenched whenever an F is + + + align:start position:0% +completely quenched whenever an F is +large when F is 0.01 for instance this + + align:start position:0% +large when F is 0.01 for instance this + + + align:start position:0% +large when F is 0.01 for instance this +is this already stably when at point of + + align:start position:0% +is this already stably when at point of + + + align:start position:0% +is this already stably when at point of +five is here and then and so on so forth + + align:start position:0% +five is here and then and so on so forth + + + align:start position:0% +five is here and then and so on so forth +so sparse representation in particular + + align:start position:0% +so sparse representation in particular + + + align:start position:0% +so sparse representation in particular +are very effective in suppressing noise + + align:start position:0% +are very effective in suppressing noise + + + align:start position:0% +are very effective in suppressing noise +but provided the inputs have kind of + + align:start position:0% +but provided the inputs have kind of + + + align:start position:0% +but provided the inputs have kind of +unsupervised learning encoded into them + + align:start position:0% +unsupervised learning encoded into them + + + align:start position:0% +unsupervised learning encoded into them +which embed into them the cluster + + align:start position:0% +which embed into them the cluster + + + align:start position:0% +which embed into them the cluster +structure of the input okay the same or + + align:start position:0% +structure of the input okay the same or + + + align:start position:0% +structure of the input okay the same or +similar thing is true for Q for these + + align:start position:0% +similar thing is true for Q for these + + + align:start position:0% +similar thing is true for Q for these +correlations if you look at the this was + + align:start position:0% +correlations if you look at the this was + + + align:start position:0% +correlations if you look at the this was +was a random correlation and this is a + + align:start position:0% +was a random correlation and this is a + + + align:start position:0% +was a random correlation and this is a +function of F and this is Q the + + align:start position:0% +function of F and this is Q the + + + align:start position:0% +function of F and this is Q the +correlation + + align:start position:0% +correlation + + + align:start position:0% +correlation +it's a stoical is extremely suppressed + + align:start position:0% +it's a stoical is extremely suppressed + + + align:start position:0% +it's a stoical is extremely suppressed +for for sparse representation basically + + align:start position:0% +for for sparse representation basically + + + align:start position:0% +for for sparse representation basically +it is exponentially small with one over + + align:start position:0% +it is exponentially small with one over + + + align:start position:0% +it is exponentially small with one over +F so it's basically zero for sparse + + align:start position:0% +F so it's basically zero for sparse + + + align:start position:0% +F so it's basically zero for sparse +representation which means that those + + align:start position:0% +representation which means that those + + + align:start position:0% +representation which means that those +centres look like randomly distributed + + align:start position:0% +centres look like randomly distributed + + + align:start position:0% +centres look like randomly distributed +essentially and with very small noise so + + align:start position:0% +essentially and with very small noise so + + + align:start position:0% +essentially and with very small noise so +you took this spheres and you basically + + align:start position:0% +you took this spheres and you basically + + + align:start position:0% +you took this spheres and you basically +map them into random points with a very + + align:start position:0% +map them into random points with a very + + + align:start position:0% +map them into random points with a very +small radius okay so it's not surprising + + align:start position:0% +small radius okay so it's not surprising + + + align:start position:0% +small radius okay so it's not surprising +that in this case the error for small + + align:start position:0% +that in this case the error for small + + + align:start position:0% +that in this case the error for small +for small F the error even for large + + align:start position:0% +for small F the error even for large + + + align:start position:0% +for small F the error even for large +very loud noise value with aro is + + align:start position:0% +very loud noise value with aro is + + + align:start position:0% +very loud noise value with aro is +basically small as zero nevertheless it + + align:start position:0% +basically small as zero nevertheless it + + + align:start position:0% +basically small as zero nevertheless it +is still saturating is function of the + + align:start position:0% +is still saturating is function of the + + + align:start position:0% +is still saturating is function of the +network side of the cortical size okay + + align:start position:0% +network side of the cortical size okay + + + align:start position:0% +network side of the cortical size okay +so the saturation of performance as a + + align:start position:0% +so the saturation of performance as a + + + align:start position:0% +so the saturation of performance as a +function of cortical size is the general + + align:start position:0% +function of cortical size is the general + + + align:start position:0% +function of cortical size is the general +property of such systems nevertheless + + align:start position:0% +property of such systems nevertheless + + + align:start position:0% +property of such systems nevertheless +the performance itself for any given + + align:start position:0% +the performance itself for any given + + + align:start position:0% +the performance itself for any given +size is extremely extremely impressive I + + align:start position:0% +size is extremely extremely impressive I + + + align:start position:0% +size is extremely extremely impressive I +would say when the system is passed + + align:start position:0% +would say when the system is passed + + + align:start position:0% +would say when the system is passed +and nose level is kind of moderate okay + + align:start position:0% +and nose level is kind of moderate okay + + + align:start position:0% +and nose level is kind of moderate okay +okay let me skip this because I don't + + align:start position:0% +okay let me skip this because I don't + + + align:start position:0% +okay let me skip this because I don't +have time let me briefly talk about + + align:start position:0% +have time let me briefly talk about + + + align:start position:0% +have time let me briefly talk about +extension D of this story to two + + align:start position:0% +extension D of this story to two + + + align:start position:0% +extension D of this story to two +multi-layer so we are now briefly + + align:start position:0% +multi-layer so we are now briefly + + + align:start position:0% +multi-layer so we are now briefly +discussing what happens if you take this + + align:start position:0% +discussing what happens if you take this + + + align:start position:0% +discussing what happens if you take this +story and you just propagate it as you + + align:start position:0% +story and you just propagate it as you + + + align:start position:0% +story and you just propagate it as you +go along the along the architecture so + + align:start position:0% +go along the along the architecture so + + + align:start position:0% +go along the along the architecture so +let's start with random eighths so the + + align:start position:0% +let's start with random eighths so the + + + align:start position:0% +let's start with random eighths so the +idea is maybe something is good + + align:start position:0% +idea is maybe something is good + + + align:start position:0% +idea is maybe something is good +happening although initially performance + + align:start position:0% +happening although initially performance + + + align:start position:0% +happening although initially performance +was poor maybe we can improve the + + align:start position:0% +was poor maybe we can improve the + + + align:start position:0% +was poor maybe we can improve the +performance by cascading such layers and + + align:start position:0% +performance by cascading such layers and + + + align:start position:0% +performance by cascading such layers and +the answer is no in particularly the + + align:start position:0% +the answer is no in particularly the + + + align:start position:0% +the answer is no in particularly the +noise level this is now the number of + + align:start position:0% +noise level this is now the number of + + + align:start position:0% +noise level this is now the number of +layers go to discuss before is here and + + align:start position:0% +layers go to discuss before is here and + + + align:start position:0% +layers go to discuss before is here and +you see the problem becomes worse and + + align:start position:0% +you see the problem becomes worse and + + + align:start position:0% +you see the problem becomes worse and +worse as you continue to propagate those + + align:start position:0% +worse as you continue to propagate those + + + align:start position:0% +worse as you continue to propagate those +signals the lowest the noise is + + align:start position:0% +signals the lowest the noise is + + + align:start position:0% +signals the lowest the noise is +amplified and essentially goes to one so + + align:start position:0% +amplified and essentially goes to one so + + + align:start position:0% +amplified and essentially goes to one so +basically you'll get just random + + align:start position:0% +basically you'll get just random + + + align:start position:0% +basically you'll get just random +performance if you keep doing it with + + align:start position:0% +performance if you keep doing it with + + + align:start position:0% +performance if you keep doing it with +random waves and the reason is very the + + align:start position:0% +random waves and the reason is very the + + + align:start position:0% +random waves and the reason is very the +reason the reason is basically that if + + align:start position:0% +reason the reason is basically that if + + + align:start position:0% +reason the reason is basically that if +you think about the mapping from one + + align:start position:0% +you think about the mapping from one + + + align:start position:0% +you think about the mapping from one +layer of noise tune to lab tune another + + align:start position:0% +layer of noise tune to lab tune another + + + align:start position:0% +layer of noise tune to lab tune another +layer of noise there are two fixed point + + align:start position:0% +layer of noise there are two fixed point + + + align:start position:0% +layer of noise there are two fixed point +and zero and one the zero fixed point is + + align:start position:0% +and zero and one the zero fixed point is + + + align:start position:0% +and zero and one the zero fixed point is +unstable + + align:start position:0% +unstable + + + align:start position:0% +unstable +everything goes eventually to one so + + align:start position:0% +everything goes eventually to one so + + + align:start position:0% +everything goes eventually to one so +it's it is a nice I think it's a nice + + align:start position:0% +it's it is a nice I think it's a nice + + + align:start position:0% +it's it is a nice I think it's a nice +this system gives you a nice perspective + + align:start position:0% +this system gives you a nice perspective + + + align:start position:0% +this system gives you a nice perspective +about this a distant deep network by + + align:start position:0% +about this a distant deep network by + + + align:start position:0% +about this a distant deep network by +thinking about is a kind of dynamical + + align:start position:0% +thinking about is a kind of dynamical + + + align:start position:0% +thinking about is a kind of dynamical +system for instance what is the level of + + align:start position:0% +system for instance what is the level of + + + align:start position:0% +system for instance what is the level of +noise at one there and how it is how + + align:start position:0% +noise at one there and how it is how + + + align:start position:0% +noise at one there and how it is how +it's related to the level of noise it + + align:start position:0% +it's related to the level of noise it + + + align:start position:0% +it's related to the level of noise it +previously so it's connect iterative map + + align:start position:0% +previously so it's connect iterative map + + + align:start position:0% +previously so it's connect iterative map +Delta n versus Delta n minus 1 and + + align:start position:0% +Delta n versus Delta n minus 1 and + + + align:start position:0% +Delta n versus Delta n minus 1 and +what's good about it this once you kind + + align:start position:0% +what's good about it this once you kind + + + align:start position:0% +what's good about it this once you kind +of draw this curve what one layer is + + align:start position:0% +of draw this curve what one layer is + + + align:start position:0% +of draw this curve what one layer is +mapped to another layer you can know + + align:start position:0% +mapped to another layer you can know + + + align:start position:0% +mapped to another layer you can know +what happens to a deep network because + + align:start position:0% +what happens to a deep network because + + + align:start position:0% +what happens to a deep network because +just iterate this you have to find what + + align:start position:0% +just iterate this you have to find what + + + align:start position:0% +just iterate this you have to find what +are the fixed points and which one is + + align:start position:0% +are the fixed points and which one is + + + align:start position:0% +are the fixed points and which one is +stable which one is not in this case the + + align:start position:0% +stable which one is not in this case the + + + align:start position:0% +stable which one is not in this case the +one is stable the zero is unstable so + + align:start position:0% +one is stable the zero is unstable so + + + align:start position:0% +one is stable the zero is unstable so +unfortunately from any level of noise + + align:start position:0% +unfortunately from any level of noise + + + align:start position:0% +unfortunately from any level of noise +that you'll start you eventually go to + + align:start position:0% +that you'll start you eventually go to + + + align:start position:0% +that you'll start you eventually go to +two one + + align:start position:0% +two one + + + align:start position:0% +two one +okay correlations is similar story but I + + align:start position:0% +okay correlations is similar story but I + + + align:start position:0% +okay correlations is similar story but I +and the arrow will go to 2.5 okay so + + align:start position:0% +and the arrow will go to 2.5 okay so + + + align:start position:0% +and the arrow will go to 2.5 okay so +that's very bad okay there are cases by + + align:start position:0% +that's very bad okay there are cases by + + + align:start position:0% +that's very bad okay there are cases by +the way that you can find parameters + + align:start position:0% +the way that you can find parameters + + + align:start position:0% +the way that you can find parameters +where initially you improve like here + + align:start position:0% +where initially you improve like here + + + align:start position:0% +where initially you improve like here +but then eventually it will it will go + + align:start position:0% +but then eventually it will it will go + + + align:start position:0% +but then eventually it will it will go +to 0.5 now if we do similar if we + + align:start position:0% +to 0.5 now if we do similar if we + + + align:start position:0% +to 0.5 now if we do similar if we +compare this to what happened to the + + align:start position:0% +compare this to what happened to the + + + align:start position:0% +compare this to what happened to the +structure wait if you keep doing the + + align:start position:0% +structure wait if you keep doing the + + + align:start position:0% +structure wait if you keep doing the +same kind of unsupervised hebbian + + align:start position:0% +same kind of unsupervised hebbian + + + align:start position:0% +same kind of unsupervised hebbian +learning from one layer to another and + + align:start position:0% +learning from one layer to another and + + + align:start position:0% +learning from one layer to another and +and I'll skip the details you see the + + align:start position:0% +and I'll skip the details you see the + + + align:start position:0% +and I'll skip the details you see the +opposite so here are parameters + + align:start position:0% +opposite so here are parameters + + + align:start position:0% +opposite so here are parameters +parameter value in which one stage of + + align:start position:0% +parameter value in which one stage of + + + align:start position:0% +parameter value in which one stage of +expansion stage is is actually + + align:start position:0% +expansion stage is is actually + + + align:start position:0% +expansion stage is is actually +increasing the noise and this is because + + align:start position:0% +increasing the noise and this is because + + + align:start position:0% +increasing the noise and this is because +F is small is not is not too small and + + align:start position:0% +F is small is not is not too small and + + + align:start position:0% +F is small is not is not too small and +the load is large and the noise is + + align:start position:0% +the load is large and the noise is + + + align:start position:0% +the load is large and the noise is +starting so you can have such iteration + + align:start position:0% +starting so you can have such iteration + + + align:start position:0% +starting so you can have such iteration +but even in such situation eventually + + align:start position:0% +but even in such situation eventually + + + align:start position:0% +but even in such situation eventually +the system goes into into stages where + + align:start position:0% +the system goes into into stages where + + + align:start position:0% +the system goes into into stages where +the noise basically goes to zero and if + + align:start position:0% +the noise basically goes to zero and if + + + align:start position:0% +the noise basically goes to zero and if +you compare the the story why it is so + + align:start position:0% +you compare the the story why it is so + + + align:start position:0% +you compare the the story why it is so +two kind of iterative met in my picture + + align:start position:0% +two kind of iterative met in my picture + + + align:start position:0% +two kind of iterative met in my picture +you see that the picture is very + + align:start position:0% +you see that the picture is very + + + align:start position:0% +you see that the picture is very +different you have one fixed point at + + align:start position:0% +different you have one fixed point at + + + align:start position:0% +different you have one fixed point at +zero you have one fixed point at one you + + align:start position:0% +zero you have one fixed point at one you + + + align:start position:0% +zero you have one fixed point at one you +have intermediate fixed point at a high + + align:start position:0% +have intermediate fixed point at a high + + + align:start position:0% +have intermediate fixed point at a high +value but this is an unstable fixed + + align:start position:0% +value but this is an unstable fixed + + + align:start position:0% +value but this is an unstable fixed +point at both of them a stable fixed + + align:start position:0% +point at both of them a stable fixed + + + align:start position:0% +point at both of them a stable fixed +point so if you start from even from + + align:start position:0% +point so if you start from even from + + + align:start position:0% +point so if you start from even from +large values of noise eventually you + + align:start position:0% +large values of noise eventually you + + + align:start position:0% +large values of noise eventually you +will iterate to zero so it does buy you + + align:start position:0% +will iterate to zero so it does buy you + + + align:start position:0% +will iterate to zero so it does buy you +to actually go into several stages of of + + align:start position:0% +to actually go into several stages of of + + + align:start position:0% +to actually go into several stages of of +this deep network to make sure that the + + align:start position:0% +this deep network to make sure that the + + + align:start position:0% +this deep network to make sure that the +noise is suppressed to zero + + align:start position:0% +noise is suppressed to zero + + + align:start position:0% +noise is suppressed to zero +similarly from the correlations even if + + align:start position:0% +similarly from the correlations even if + + + align:start position:0% +similarly from the correlations even if +the parameters are such that initially + + align:start position:0% +the parameters are such that initially + + + align:start position:0% +the parameters are such that initially +correlations are increased and you can + + align:start position:0% +correlations are increased and you can + + + align:start position:0% +correlations are increased and you can +find parameters like that eventually + + align:start position:0% +find parameters like that eventually + + + align:start position:0% +find parameters like that eventually +correlations will go to almost zero okay + + align:start position:0% +correlations will go to almost zero okay + + + align:start position:0% +correlations will go to almost zero okay +and this is comparison of the grid out + + align:start position:0% +and this is comparison of the grid out + + + align:start position:0% +and this is comparison of the grid out +MO as a function of the layers we + + align:start position:0% +MO as a function of the layers we + + + align:start position:0% +MO as a function of the layers we +structured weights and I compare it with + + align:start position:0% +structured weights and I compare it with + + + align:start position:0% +structured weights and I compare it with +the readout error of infinity wide layer + + align:start position:0% +the readout error of infinity wide layer + + + align:start position:0% +the readout error of infinity wide layer +kind of a + + align:start position:0% +kind of a + + + align:start position:0% +kind of a +colonel with infinitely white colonel + + align:start position:0% +colonel with infinitely white colonel + + + align:start position:0% +colonel with infinitely white colonel +and you can see that that at least for + + align:start position:0% +and you can see that that at least for + + + align:start position:0% +and you can see that that at least for +here I compare the same type of + + align:start position:0% +here I compare the same type of + + + align:start position:0% +here I compare the same type of +unsupervised learning but two different + + align:start position:0% +unsupervised learning but two different + + + align:start position:0% +unsupervised learning but two different +architecture one is deep network + + align:start position:0% +architecture one is deep network + + + align:start position:0% +architecture one is deep network +architecture another one is shallow + + align:start position:0% +architecture another one is shallow + + + align:start position:0% +architecture another one is shallow +architecture infinitely wide and I'm not + + align:start position:0% +architecture infinitely wide and I'm not + + + align:start position:0% +architecture infinitely wide and I'm not +claiming that we can show that there is + + align:start position:0% +claiming that we can show that there is + + + align:start position:0% +claiming that we can show that there is +no kernel or shallow architecture which + + align:start position:0% +no kernel or shallow architecture which + + + align:start position:0% +no kernel or shallow architecture which +will do better but I'm saying if we + + align:start position:0% +will do better but I'm saying if we + + + align:start position:0% +will do better but I'm saying if we +compare the same learning rule but with + + align:start position:0% +compare the same learning rule but with + + + align:start position:0% +compare the same learning rule but with +it but with the two different + + align:start position:0% +it but with the two different + + + align:start position:0% +it but with the two different +architecture you find that you do gain + + align:start position:0% +architecture you find that you do gain + + + align:start position:0% +architecture you find that you do gain +by going into multiple stages of + + align:start position:0% +by going into multiple stages of + + + align:start position:0% +by going into multiple stages of +non-linearity then by using an + + align:start position:0% +non-linearity then by using an + + + align:start position:0% +non-linearity then by using an +infinitely wide layer ok I'll skip this + + align:start position:0% +infinitely wide layer ok I'll skip this + + + align:start position:0% +infinitely wide layer ok I'll skip this +I want to go briefly to to two more + + align:start position:0% +I want to go briefly to to two more + + + align:start position:0% +I want to go briefly to to two more +issues one issue is the recurrent + + align:start position:0% +issues one issue is the recurrent + + + align:start position:0% +issues one issue is the recurrent +networks why recurrent networks are the + + align:start position:0% +networks why recurrent networks are the + + + align:start position:0% +networks why recurrent networks are the +primary reason is that in each one of + + align:start position:0% +primary reason is that in each one of + + + align:start position:0% +primary reason is that in each one of +those stages that I have a fail to if + + align:start position:0% +those stages that I have a fail to if + + + align:start position:0% +those stages that I have a fail to if +you look at the biology on most of them + + align:start position:0% +you look at the biology on most of them + + + align:start position:0% +you look at the biology on most of them +maybe not all of them but most of them + + align:start position:0% +maybe not all of them but most of them + + + align:start position:0% +maybe not all of them but most of them +indefinitely in neocortex you'll find + + align:start position:0% +indefinitely in neocortex you'll find + + + align:start position:0% +indefinitely in neocortex you'll find +massive recurrent or lateral + + align:start position:0% +massive recurrent or lateral + + + align:start position:0% +massive recurrent or lateral +interactions between each one of the + + align:start position:0% +interactions between each one of the + + + align:start position:0% +interactions between each one of the +layers so again we would like to ask + + align:start position:0% +layers so again we would like to ask + + + align:start position:0% +layers so again we would like to ask +what is the what is the what is the + + align:start position:0% +what is the what is the what is the + + + align:start position:0% +what is the what is the what is the +computational advantage of having this + + align:start position:0% +computational advantage of having this + + + align:start position:0% +computational advantage of having this +recurrent layer now in in our case we + + align:start position:0% +recurrent layer now in in our case we + + + align:start position:0% +recurrent layer now in in our case we +had an extra motivation and this is + + align:start position:0% +had an extra motivation and this is + + + align:start position:0% +had an extra motivation and this is +remember that I started in saying that + + align:start position:0% +remember that I started in saying that + + + align:start position:0% +remember that I started in saying that +in some cases there is experimental + + align:start position:0% +in some cases there is experimental + + + align:start position:0% +in some cases there is experimental +evidence that the initial projection is + + align:start position:0% +evidence that the initial projection is + + + align:start position:0% +evidence that the initial projection is +random so that we asked ourselves what + + align:start position:0% +random so that we asked ourselves what + + + align:start position:0% +random so that we asked ourselves what +happens if we do this if we start from + + align:start position:0% +happens if we do this if we start from + + + align:start position:0% +happens if we do this if we start from +random projection feed-forward + + align:start position:0% +random projection feed-forward + + + align:start position:0% +random projection feed-forward +projection and then add recurrent + + align:start position:0% +projection and then add recurrent + + + align:start position:0% +projection and then add recurrent +connections think about it as from the + + align:start position:0% +connections think about it as from the + + + align:start position:0% +connections think about it as from the +or factory bomb for instance to perform + + align:start position:0% +or factory bomb for instance to perform + + + align:start position:0% +or factory bomb for instance to perform +cortex perhaps random fitful projections + + align:start position:0% +cortex perhaps random fitful projections + + + align:start position:0% +cortex perhaps random fitful projections +but then the Association recurrent + + align:start position:0% +but then the Association recurrent + + + align:start position:0% +but then the Association recurrent +connections in period from cortex our + + align:start position:0% +connections in period from cortex our + + + align:start position:0% +connections in period from cortex our +structure how do we do that we start we + + align:start position:0% +structure how do we do that we start we + + + align:start position:0% +structure how do we do that we start we +imagine starting from random + + align:start position:0% +imagine starting from random + + + align:start position:0% +imagine starting from random +generating a presentation initial + + align:start position:0% +generating a presentation initial + + + align:start position:0% +generating a presentation initial +presentation by the random projection + + align:start position:0% +presentation by the random projection + + + align:start position:0% +presentation by the random projection +and then stabilizing those of + + align:start position:0% +and then stabilizing those of + + + align:start position:0% +and then stabilizing those of +presentation into attractors by the + + align:start position:0% +presentation into attractors by the + + + align:start position:0% +presentation into attractors by the +recurrent connections and that actually + + align:start position:0% +recurrent connections and that actually + + + align:start position:0% +recurrent connections and that actually +works pretty well it's not it's not it's + + align:start position:0% +works pretty well it's not it's not it's + + + align:start position:0% +works pretty well it's not it's not it's +not the optimal architecture but it's + + align:start position:0% +not the optimal architecture but it's + + + align:start position:0% +not the optimal architecture but it's +pretty well for instance noise which is + + align:start position:0% +pretty well for instance noise which is + + + align:start position:0% +pretty well for instance noise which is +initially increased by the random + + align:start position:0% +initially increased by the random + + + align:start position:0% +initially increased by the random +projections will quenched by convergence + + align:start position:0% +projections will quenched by convergence + + + align:start position:0% +projections will quenched by convergence +two attractor and similarly Q will not + + align:start position:0% +two attractor and similarly Q will not + + + align:start position:0% +two attractor and similarly Q will not +go to zero but will not continue growing + + align:start position:0% +go to zero but will not continue growing + + + align:start position:0% +go to zero but will not continue growing +but we'll go to intimately and and the + + align:start position:0% +but we'll go to intimately and and the + + + align:start position:0% +but we'll go to intimately and and the +arrow is is pretty well so if you look + + align:start position:0% +arrow is is pretty well so if you look + + + align:start position:0% +arrow is is pretty well so if you look +at the in this case the arrow really + + align:start position:0% +at the in this case the arrow really + + + align:start position:0% +at the in this case the arrow really +goes down to very low values but now + + align:start position:0% +goes down to very low values but now + + + align:start position:0% +goes down to very low values but now +it's not layers now it is the number of + + align:start position:0% +it's not layers now it is the number of + + + align:start position:0% +it's not layers now it is the number of +iterations of the recurrent connections + + align:start position:0% +iterations of the recurrent connections + + + align:start position:0% +iterations of the recurrent connections +so you start from just input layer or + + align:start position:0% +so you start from just input layer or + + + align:start position:0% +so you start from just input layer or +put project random projection and then + + align:start position:0% +put project random projection and then + + + align:start position:0% +put project random projection and then +you iterate the dynamics and it goes to + + align:start position:0% +you iterate the dynamics and it goes to + + + align:start position:0% +you iterate the dynamics and it goes to +zero so it's not the layers it's just + + align:start position:0% +zero so it's not the layers it's just + + + align:start position:0% +zero so it's not the layers it's just +the dynamics of the I conversion to + + align:start position:0% +the dynamics of the I conversion to + + + align:start position:0% +the dynamics of the I conversion to +attractor okay my final point I have + + align:start position:0% +attractor okay my final point I have + + + align:start position:0% +attractor okay my final point I have +three from four minutes okay + + align:start position:0% +three from four minutes okay + + + align:start position:0% +three from four minutes okay +my final points are before wrapping up + + align:start position:0% +my final points are before wrapping up + + + align:start position:0% +my final points are before wrapping up +is the question of top-down so we can't + + align:start position:0% +is the question of top-down so we can't + + + align:start position:0% +is the question of top-down so we can't +move really talked about it but + + align:start position:0% +move really talked about it but + + + align:start position:0% +move really talked about it but +incorporating contextual knowledge is a + + align:start position:0% +incorporating contextual knowledge is a + + + align:start position:0% +incorporating contextual knowledge is a +major question how can you improve on + + align:start position:0% +major question how can you improve on + + + align:start position:0% +major question how can you improve on +deep networks by incorporating not + + align:start position:0% +deep networks by incorporating not + + + align:start position:0% +deep networks by incorporating not +simply the feed-forward sensory input + + align:start position:0% +simply the feed-forward sensory input + + + align:start position:0% +simply the feed-forward sensory input +but other sort of knowledge about this + + align:start position:0% +but other sort of knowledge about this + + + align:start position:0% +but other sort of knowledge about this +particular stimulus and it's important + + align:start position:0% +particular stimulus and it's important + + + align:start position:0% +particular stimulus and it's important +that we are not talking about knowledge + + align:start position:0% +that we are not talking about knowledge + + + align:start position:0% +that we are not talking about knowledge +about the statistics of the input which + + align:start position:0% +about the statistics of the input which + + + align:start position:0% +about the statistics of the input which +can be incorporated into the learning of + + align:start position:0% +can be incorporated into the learning of + + + align:start position:0% +can be incorporated into the learning of +the feed-forward one but we're talking + + align:start position:0% +the feed-forward one but we're talking + + + align:start position:0% +the feed-forward one but we're talking +about inputs which our knowledge which + + align:start position:0% +about inputs which our knowledge which + + + align:start position:0% +about inputs which our knowledge which +we have now on the network which already + + align:start position:0% +we have now on the network which already + + + align:start position:0% +we have now on the network which already +has learned whatever it has learned so + + align:start position:0% +has learned whatever it has learned so + + + align:start position:0% +has learned whatever it has learned so +we have a mature Network whatever the + + align:start position:0% +we have a mature Network whatever the + + + align:start position:0% +we have a mature Network whatever the +architecture is we have a sensory input + + align:start position:0% +architecture is we have a sensory input + + + align:start position:0% +architecture is we have a sensory input +gross feed-forward and now we have + + align:start position:0% +gross feed-forward and now we have + + + align:start position:0% +gross feed-forward and now we have +additional information about context for + + align:start position:0% +additional information about context for + + + align:start position:0% +additional information about context for +instance that we want to incorporate + + align:start position:0% +instance that we want to incorporate + + + align:start position:0% +instance that we want to incorporate +with the sensory input to + + align:start position:0% +with the sensory input to + + + align:start position:0% +with the sensory input to +to improve the performance so how do we + + align:start position:0% +to improve the performance so how do we + + + align:start position:0% +to improve the performance so how do we +do that it that's it's a nut it turns + + align:start position:0% +do that it that's it's a nut it turns + + + align:start position:0% +do that it that's it's a nut it turns +out to be non-trivial a computational + + align:start position:0% +out to be non-trivial a computational + + + align:start position:0% +out to be non-trivial a computational +problem it is very straightforward to do + + align:start position:0% +problem it is very straightforward to do + + + align:start position:0% +problem it is very straightforward to do +it in in Bayesian framework where you + + align:start position:0% +it in in Bayesian framework where you + + + align:start position:0% +it in in Bayesian framework where you +simply update the prior of what the + + align:start position:0% +simply update the prior of what the + + + align:start position:0% +simply update the prior of what the +sensory input is by this contextual + + align:start position:0% +sensory input is by this contextual + + + align:start position:0% +sensory input is by this contextual +information but but if you want to + + align:start position:0% +information but but if you want to + + + align:start position:0% +information but but if you want to +implement it in a network you find that + + align:start position:0% +implement it in a network you find that + + + align:start position:0% +implement it in a network you find that +it's not it's not easy to to find the + + align:start position:0% +it's not it's not easy to to find the + + + align:start position:0% +it's not it's not easy to to find the +appropriate architecture so I just + + align:start position:0% +appropriate architecture so I just + + + align:start position:0% +appropriate architecture so I just +briefly talked about I talked about how + + align:start position:0% +briefly talked about I talked about how + + + align:start position:0% +briefly talked about I talked about how +we do it so so imagine you have again + + align:start position:0% +we do it so so imagine you have again + + + align:start position:0% +we do it so so imagine you have again +this sensory input but now there is some + + align:start position:0% +this sensory input but now there is some + + + align:start position:0% +this sensory input but now there is some +context different context and and + + align:start position:0% +context different context and and + + + align:start position:0% +context different context and and +imagine you have an information that the + + align:start position:0% +imagine you have an information that the + + + align:start position:0% +imagine you have an information that the +input is coming from that particular set + + align:start position:0% +input is coming from that particular set + + + align:start position:0% +input is coming from that particular set +of a part of state space so basically + + align:start position:0% +of a part of state space so basically + + + align:start position:0% +of a part of state space so basically +the question is how to amplify + + align:start position:0% +the question is how to amplify + + + align:start position:0% +the question is how to amplify +selectively a specific set of states in + + align:start position:0% +selectively a specific set of states in + + + align:start position:0% +selectively a specific set of states in +a distributed representation so usually + + align:start position:0% +a distributed representation so usually + + + align:start position:0% +a distributed representation so usually +when you talk about attention or gating + + align:start position:0% +when you talk about attention or gating + + + align:start position:0% +when you talk about attention or gating +on questions like that we think about + + align:start position:0% +on questions like that we think about + + + align:start position:0% +on questions like that we think about +okay we have these neurons we suppress + + align:start position:0% +okay we have these neurons we suppress + + + align:start position:0% +okay we have these neurons we suppress +those and amp or maybe amplify other + + align:start position:0% +those and amp or maybe amplify other + + + align:start position:0% +those and amp or maybe amplify other +ones or we have a set of axons or + + align:start position:0% +ones or we have a set of axons or + + + align:start position:0% +ones or we have a set of axons or +pathways we suppress those and amplify + + align:start position:0% +pathways we suppress those and amplify + + + align:start position:0% +pathways we suppress those and amplify +those but what about a representation + + align:start position:0% +those but what about a representation + + + align:start position:0% +those but what about a representation +which is more distributed where you have + + align:start position:0% +which is more distributed where you have + + + align:start position:0% +which is more distributed where you have +to really suppress states rather than + + align:start position:0% +to really suppress states rather than + + + align:start position:0% +to really suppress states rather than +no.11 populations so I just want one go + + align:start position:0% +no.11 populations so I just want one go + + + align:start position:0% +no.11 populations so I just want one go +again it's a complicated architecture + + align:start position:0% +again it's a complicated architecture + + + align:start position:0% +again it's a complicated architecture +but basically we're using some some sort + + align:start position:0% +but basically we're using some some sort + + + align:start position:0% +but basically we're using some some sort +of a mixed representation where we take + + align:start position:0% +of a mixed representation where we take + + + align:start position:0% +of a mixed representation where we take +the sensory input and categorical or + + align:start position:0% +the sensory input and categorical or + + + align:start position:0% +the sensory input and categorical or +contextual input mix them non-linearity + + align:start position:0% +contextual input mix them non-linearity + + + align:start position:0% +contextual input mix them non-linearity +use them to clean it and and propagate + + align:start position:0% +use them to clean it and and propagate + + + align:start position:0% +use them to clean it and and propagate +this so it's a more complicated + + align:start position:0% +this so it's a more complicated + + + align:start position:0% +this so it's a more complicated +architecture but it works beautifully + + align:start position:0% +architecture but it works beautifully + + + align:start position:0% +architecture but it works beautifully +let me show you here an example you have + + align:start position:0% +let me show you here an example you have + + + align:start position:0% +let me show you here an example you have +a flavor of what we are doing so now the + + align:start position:0% +a flavor of what we are doing so now the + + + align:start position:0% +a flavor of what we are doing so now the +input we have we have those 900 spheres + + align:start position:0% +input we have we have those 900 spheres + + + align:start position:0% +input we have we have those 900 spheres +or templates but they are organized + + align:start position:0% +or templates but they are organized + + + align:start position:0% +or templates but they are organized +- with 30 categories and 30 tokens per + + align:start position:0% +- with 30 categories and 30 tokens per + + + align:start position:0% +- with 30 categories and 30 tokens per +category okay + + align:start position:0% +category okay + + + align:start position:0% +category okay +now the the tokens which are the actual + + align:start position:0% +now the the tokens which are the actual + + + align:start position:0% +now the the tokens which are the actual +sensory inputs are represented but let's + + align:start position:0% +sensory inputs are represented but let's + + + align:start position:0% +sensory inputs are represented but let's +say 200 neurons and you have a small + + align:start position:0% +say 200 neurons and you have a small + + + align:start position:0% +say 200 neurons and you have a small +number of neurons representing category + + align:start position:0% +number of neurons representing category + + + align:start position:0% +number of neurons representing category +maybe 20s enough so that's important + + align:start position:0% +maybe 20s enough so that's important + + + align:start position:0% +maybe 20s enough so that's important +that you don't have to really expand + + align:start position:0% +that you don't have to really expand + + + align:start position:0% +that you don't have to really expand +dramatically the representation okay so + + align:start position:0% +dramatically the representation okay so + + + align:start position:0% +dramatically the representation okay so +this is the input and now we have very + + align:start position:0% +this is the input and now we have very + + + align:start position:0% +this is the input and now we have very +noisy inputs if you look at the readout + + align:start position:0% +noisy inputs if you look at the readout + + + align:start position:0% +noisy inputs if you look at the readout +this is layers here and there is read + + align:start position:0% +this is layers here and there is read + + + align:start position:0% +this is layers here and there is read +out arrow if you do it on the input + + align:start position:0% +out arrow if you do it on the input + + + align:start position:0% +out arrow if you do it on the input +layer or any subsequent layer here but + + align:start position:0% +layer or any subsequent layer here but + + + align:start position:0% +layer or any subsequent layer here but +without top-down information we + + align:start position:0% +without top-down information we + + + align:start position:0% +without top-down information we +structured interactions and all that I + + align:start position:0% +structured interactions and all that I + + + align:start position:0% +structured interactions and all that I +told you this is such a noisy input + + align:start position:0% +told you this is such a noisy input + + + align:start position:0% +told you this is such a noisy input +where the performance is basically 0.5 + + align:start position:0% +where the performance is basically 0.5 + + + align:start position:0% +where the performance is basically 0.5 +okay there is nothing that you can do + + align:start position:0% +okay there is nothing that you can do + + + align:start position:0% +okay there is nothing that you can do +without top-down information in this + + align:start position:0% +without top-down information in this + + + align:start position:0% +without top-down information in this +network you can ask what what will be + + align:start position:0% +network you can ask what what will be + + + align:start position:0% +network you can ask what what will be +the performance if you have an ideal + + align:start position:0% +the performance if you have an ideal + + + align:start position:0% +the performance if you have an ideal +observer that looks at the in noisy + + align:start position:0% +observer that looks at the in noisy + + + align:start position:0% +observer that looks at the in noisy +input and makes maximum likelihood + + align:start position:0% +input and makes maximum likelihood + + + align:start position:0% +input and makes maximum likelihood +maximum likelihood categorization well + + align:start position:0% +maximum likelihood categorization well + + + align:start position:0% +maximum likelihood categorization well +then it will do much better also not + + align:start position:0% +then it will do much better also not + + + align:start position:0% +then it will do much better also not +zero so these are this level okay this + + align:start position:0% +zero so these are this level okay this + + + align:start position:0% +zero so these are this level okay this +is this higher error is in virtue of the + + align:start position:0% +is this higher error is in virtue of the + + + align:start position:0% +is this higher error is in virtue of the +fact that this network is still not + + align:start position:0% +fact that this network is still not + + + align:start position:0% +fact that this network is still not +doing what an optimal maximum likelihood + + align:start position:0% +doing what an optimal maximum likelihood + + + align:start position:0% +doing what an optimal maximum likelihood +observer will do okay so this is the + + align:start position:0% +observer will do okay so this is the + + + align:start position:0% +observer will do okay so this is the +network this is a maximum likelihood + + align:start position:0% +network this is a maximum likelihood + + + align:start position:0% +network this is a maximum likelihood +without both of them without extra + + align:start position:0% +without both of them without extra + + + align:start position:0% +without both of them without extra +top-down information and in the network + + align:start position:0% +top-down information and in the network + + + align:start position:0% +top-down information and in the network +that I kind of hinted about if you add + + align:start position:0% +that I kind of hinted about if you add + + + align:start position:0% +that I kind of hinted about if you add +this top-down information by generating + + align:start position:0% +this top-down information by generating + + + align:start position:0% +this top-down information by generating +mixed representations you get the + + align:start position:0% +mixed representations you get the + + + align:start position:0% +mixed representations you get the +performance which is really dramatic + + align:start position:0% +performance which is really dramatic + + + align:start position:0% +performance which is really dramatic +dramatically improves and as you keep + + align:start position:0% +dramatically improves and as you keep + + + align:start position:0% +dramatically improves and as you keep +doing it one layer from another you + + align:start position:0% +doing it one layer from another you + + + align:start position:0% +doing it one layer from another you +really get a very very nice performance + + align:start position:0% +really get a very very nice performance + + + align:start position:0% +really get a very very nice performance +okay so maybe did summarize the day's + + align:start position:0% +okay so maybe did summarize the day's + + + align:start position:0% +okay so maybe did summarize the day's +gonna the whole the whole + + align:start position:0% + + + + align:start position:0% + +there's one more before summarizing yeah + + align:start position:0% +there's one more before summarizing yeah + + + align:start position:0% +there's one more before summarizing yeah +okay before that okay so to two points + + align:start position:0% +okay before that okay so to two points + + + align:start position:0% +okay before that okay so to two points +to bear in mind one of them is that what + + align:start position:0% +to bear in mind one of them is that what + + + align:start position:0% +to bear in mind one of them is that what +I discussed to you today relies on on on + + align:start position:0% +I discussed to you today relies on on on + + + align:start position:0% +I discussed to you today relies on on on +assuming either random comparing random + + align:start position:0% +assuming either random comparing random + + + align:start position:0% +assuming either random comparing random +projection to unsupervised learning of a + + align:start position:0% +projection to unsupervised learning of a + + + align:start position:0% +projection to unsupervised learning of a +very simple type of kind of hedging type + + align:start position:0% +very simple type of kind of hedging type + + + align:start position:0% +very simple type of kind of hedging type +the output can be happier nor perceptron + + align:start position:0% +the output can be happier nor perceptron + + + align:start position:0% +the output can be happier nor perceptron +or SVM and so on you could ask what + + align:start position:0% +or SVM and so on you could ask what + + + align:start position:0% +or SVM and so on you could ask what +happens if you use learning rules more + + align:start position:0% +happens if you use learning rules more + + + align:start position:0% +happens if you use learning rules more +sophisticated learning goals for the + + align:start position:0% +sophisticated learning goals for the + + + align:start position:0% +sophisticated learning goals for the +unsupervised wait some of them we've + + align:start position:0% +unsupervised wait some of them we've + + + align:start position:0% +unsupervised wait some of them we've +studied but anyway that's something + + align:start position:0% +studied but anyway that's something + + + align:start position:0% +studied but anyway that's something +which is important to to explore and and + + align:start position:0% +which is important to to explore and and + + + align:start position:0% +which is important to to explore and and +another very important issue for + + align:start position:0% +another very important issue for + + + align:start position:0% +another very important issue for +thinking about object recognition in + + align:start position:0% +thinking about object recognition in + + + align:start position:0% +thinking about object recognition in +vision and and in other real-life + + align:start position:0% +vision and and in other real-life + + + align:start position:0% +vision and and in other real-life +problem is input statistics because what + + align:start position:0% +problem is input statistics because what + + + align:start position:0% +problem is input statistics because what +we assumed is a very simple mixture of + + align:start position:0% +we assumed is a very simple mixture of + + + align:start position:0% +we assumed is a very simple mixture of +Gaussian model so you can think about + + align:start position:0% +Gaussian model so you can think about + + + align:start position:0% +Gaussian model so you can think about +the task of the network is to take + + align:start position:0% +the task of the network is to take + + + align:start position:0% +the task of the network is to take +they're in violation away from the + + align:start position:0% +they're in violation away from the + + + align:start position:0% +they're in violation away from the +center this spherical valuation and to + + align:start position:0% +center this spherical valuation and to + + + align:start position:0% +center this spherical valuation and to +generate a presentation which is + + align:start position:0% +generate a presentation which is + + + align:start position:0% +generate a presentation which is +environed to that but this is a very + + align:start position:0% +environed to that but this is a very + + + align:start position:0% +environed to that but this is a very +simple invent + + align:start position:0% +simple invent + + + align:start position:0% +simple invent +the invariance was simply restricted to + + align:start position:0% +the invariance was simply restricted to + + + align:start position:0% +the invariance was simply restricted to +this simple geometric structures more + + align:start position:0% + + + + align:start position:0% + +problems which are closer to what + + align:start position:0% +problems which are closer to what + + + align:start position:0% +problems which are closer to what +real-life problems are will have inputs + + align:start position:0% +real-life problems are will have inputs + + + align:start position:0% +real-life problems are will have inputs +which are essentially have some + + align:start position:0% +which are essentially have some + + + align:start position:0% +which are essentially have some +structure but the structure can be a + + align:start position:0% +structure but the structure can be a + + + align:start position:0% +structure but the structure can be a +variety of shapes each one of them + + align:start position:0% +variety of shapes each one of them + + + align:start position:0% +variety of shapes each one of them +correspond to an object or cluster or a + + align:start position:0% +correspond to an object or cluster or a + + + align:start position:0% +correspond to an object or cluster or a +manifold representing an entity a + + align:start position:0% +manifold representing an entity a + + + align:start position:0% +manifold representing an entity a +perceptual entity but how you go from + + align:start position:0% +perceptual entity but how you go from + + + align:start position:0% +perceptual entity but how you go from +this nice simple + + align:start position:0% +this nice simple + + + align:start position:0% +this nice simple +problem of this spherical environment + + align:start position:0% +problem of this spherical environment + + + align:start position:0% +problem of this spherical environment +to those problems it's of course a + + align:start position:0% +to those problems it's of course a + + + align:start position:0% +to those problems it's of course a +challenging problem and that's the work + + align:start position:0% +challenging problem and that's the work + + + align:start position:0% +challenging problem and that's the work +which we are now ongoing work also with + + align:start position:0% +which we are now ongoing work also with + + + align:start position:0% +which we are now ongoing work also with +us with so Eun Chun and then Lee but + + align:start position:0% +us with so Eun Chun and then Lee but + + + align:start position:0% +us with so Eun Chun and then Lee but +it's a story which is still at the stage + + align:start position:0% +it's a story which is still at the stage + + + align:start position:0% +it's a story which is still at the stage +of unfolding + + align:start position:0% + + + + align:start position:0% + +you \ No newline at end of file diff --git a/QuWEUrIzZNs.txt b/QuWEUrIzZNs.txt new file mode 100644 index 0000000000000000000000000000000000000000..7337338cd4463ecfa5e555720f5ccc83bfbd40db --- /dev/null +++ b/QuWEUrIzZNs.txt @@ -0,0 +1,11683 @@ +align:start position:0% + +okay let's go ahead and get + + align:start position:0% +okay let's go ahead and get + + + align:start position:0% +okay let's go ahead and get +started uh today I'm going to talk about + + align:start position:0% +started uh today I'm going to talk about + + + align:start position:0% +started uh today I'm going to talk about +uh start talking about random + + align:start position:0% +uh start talking about random + + + align:start position:0% +uh start talking about random +variables and uh distributions of random + + align:start position:0% +variables and uh distributions of random + + + align:start position:0% +variables and uh distributions of random +variables and uh at the end I will + + align:start position:0% +variables and uh at the end I will + + + align:start position:0% +variables and uh at the end I will +probably also uh get to a discussion of + + align:start position:0% +probably also uh get to a discussion of + + + align:start position:0% +probably also uh get to a discussion of +joint + + align:start position:0% +joint + + + align:start position:0% +joint +distributions um Tuesday then Esther's + + align:start position:0% +distributions um Tuesday then Esther's + + + align:start position:0% +distributions um Tuesday then Esther's +going to be um lecturing she's going to + + align:start position:0% +going to be um lecturing she's going to + + + align:start position:0% +going to be um lecturing she's going to +do a bunch of examples um and also talk + + align:start position:0% +do a bunch of examples um and also talk + + + align:start position:0% +do a bunch of examples um and also talk +about um you know some uh as she as she + + align:start position:0% +about um you know some uh as she as she + + + align:start position:0% +about um you know some uh as she as she +mentioned last time some data sources + + align:start position:0% +mentioned last time some data sources + + + align:start position:0% +mentioned last time some data sources +and techniques for Gathering data such + + align:start position:0% +and techniques for Gathering data such + + + align:start position:0% +and techniques for Gathering data such +as web scraping uh and then um she's + + align:start position:0% +as web scraping uh and then um she's + + + align:start position:0% +as web scraping uh and then um she's +going to play around with data a little + + align:start position:0% +going to play around with data a little + + + align:start position:0% +going to play around with data a little +bit and uh do some uh techniques that + + align:start position:0% +bit and uh do some uh techniques that + + + align:start position:0% +bit and uh do some uh techniques that +that are essentially used histograms + + align:start position:0% +that are essentially used histograms + + + align:start position:0% +that are essentially used histograms +kernel density plots so forth uh some te + + align:start position:0% +kernel density plots so forth uh some te + + + align:start position:0% +kernel density plots so forth uh some te +techniques that we essentially use to um + + align:start position:0% +techniques that we essentially use to um + + + align:start position:0% +techniques that we essentially use to um +to estimate or + + align:start position:0% +to estimate or + + + align:start position:0% +to estimate or +approximate um things like uh + + align:start position:0% +approximate um things like uh + + + align:start position:0% +approximate um things like uh +distributions of random variables okay + + align:start position:0% +distributions of random variables okay + + + align:start position:0% +distributions of random variables okay +and then uh Wednesday I'll be um + + align:start position:0% +and then uh Wednesday I'll be um + + + align:start position:0% +and then uh Wednesday I'll be um +lecturing again we'll talk about + + align:start position:0% +lecturing again we'll talk about + + + align:start position:0% +lecturing again we'll talk about +independence of random variables + + align:start position:0% +independence of random variables + + + align:start position:0% +independence of random variables +conditional distributions and maybe some + + align:start position:0% +conditional distributions and maybe some + + + align:start position:0% +conditional distributions and maybe some +other stuff too okay the recitation on + + align:start position:0% +other stuff too okay the recitation on + + + align:start position:0% +other stuff too okay the recitation on +Friday is going to be Contin uation of + + align:start position:0% +Friday is going to be Contin uation of + + + align:start position:0% +Friday is going to be Contin uation of +uh the sort of our tutorial and there + + align:start position:0% +uh the sort of our tutorial and there + + + align:start position:0% +uh the sort of our tutorial and there +could be um depending on exactly what + + align:start position:0% +could be um depending on exactly what + + + align:start position:0% +could be um depending on exactly what +gets put on the problem set there could + + align:start position:0% +gets put on the problem set there could + + + align:start position:0% +gets put on the problem set there could +be a couple little uh sort of hints + + align:start position:0% +be a couple little uh sort of hints + + + align:start position:0% +be a couple little uh sort of hints +about um you know uh issues in + + align:start position:0% +about um you know uh issues in + + + align:start position:0% +about um you know uh issues in +probability that you might need for the + + align:start position:0% +probability that you might need for the + + + align:start position:0% +probability that you might need for the +problem set in the recitation on Friday + + align:start position:0% +problem set in the recitation on Friday + + + align:start position:0% +problem set in the recitation on Friday +but it's mostly going to be on R okay + + align:start position:0% +but it's mostly going to be on R okay + + + align:start position:0% +but it's mostly going to be on R okay +questions before I get + + align:start position:0% + + + + align:start position:0% + +started okay so as I I said I'm going to + + align:start position:0% +started okay so as I I said I'm going to + + + align:start position:0% +started okay so as I I said I'm going to +start talking about this uh sort of + + align:start position:0% +start talking about this uh sort of + + + align:start position:0% +start talking about this uh sort of +mathematical construct uh called random + + align:start position:0% +mathematical construct uh called random + + + align:start position:0% +mathematical construct uh called random +variable so often times there's some + + align:start position:0% +variable so often times there's some + + + align:start position:0% +variable so often times there's some +numerical characteristic in the sample + + align:start position:0% +numerical characteristic in the sample + + + align:start position:0% +numerical characteristic in the sample +space that we're interested in so we've + + align:start position:0% +space that we're interested in so we've + + + align:start position:0% +space that we're interested in so we've +talked about a lot of you know we've + + align:start position:0% +talked about a lot of you know we've + + + align:start position:0% +talked about a lot of you know we've +seen examples of different sample spaces + + align:start position:0% +seen examples of different sample spaces + + + align:start position:0% +seen examples of different sample spaces +and some of them have you know we could + + align:start position:0% +and some of them have you know we could + + + align:start position:0% +and some of them have you know we could +we can talk about a numerical + + align:start position:0% +we can talk about a numerical + + + align:start position:0% +we can talk about a numerical +characteristic of the sample space that + + align:start position:0% +characteristic of the sample space that + + + align:start position:0% +characteristic of the sample space that +we might be interested in like the sum + + align:start position:0% +we might be interested in like the sum + + + align:start position:0% +we might be interested in like the sum +of the faces of two dice or the number + + align:start position:0% +of the faces of two dice or the number + + + align:start position:0% +of the faces of two dice or the number +of threep point field goals that Steph + + align:start position:0% +of threep point field goals that Steph + + + align:start position:0% +of threep point field goals that Steph +Curry makes in his next six attempts the + + align:start position:0% +Curry makes in his next six attempts the + + + align:start position:0% +Curry makes in his next six attempts the +number of vegetarian toppings I get on + + align:start position:0% +number of vegetarian toppings I get on + + + align:start position:0% +number of vegetarian toppings I get on +my pizza um and it's uh there's an sort + + align:start position:0% +my pizza um and it's uh there's an sort + + + align:start position:0% +my pizza um and it's uh there's an sort +of an important and useful mathematical + + align:start position:0% +of an important and useful mathematical + + + align:start position:0% +of an important and useful mathematical +construct that we use to analyze those + + align:start position:0% +construct that we use to analyze those + + + align:start position:0% +construct that we use to analyze those +numerical characteristics and it's + + align:start position:0% +numerical characteristics and it's + + + align:start position:0% +numerical characteristics and it's +called a random variable okay so a + + align:start position:0% +called a random variable okay so a + + + align:start position:0% +called a random variable okay so a +random variable is a real valued + + align:start position:0% +random variable is a real valued + + + align:start position:0% +random variable is a real valued +function whose domain is the sample + + align:start position:0% +function whose domain is the sample + + + align:start position:0% +function whose domain is the sample +space and um you know as I said it it + + align:start position:0% +space and um you know as I said it it + + + align:start position:0% +space and um you know as I said it it +sort of uh it it has a uh it's real + + align:start position:0% +sort of uh it it has a uh it's real + + + align:start position:0% +sort of uh it it has a uh it's real +valued + + align:start position:0% +valued + + + align:start position:0% +valued +so it goes from in particular the sample + + align:start position:0% +so it goes from in particular the sample + + + align:start position:0% +so it goes from in particular the sample +space to the real + + align:start position:0% +space to the real + + + align:start position:0% +space to the real +line so I don't know if this graphic + + align:start position:0% +line so I don't know if this graphic + + + align:start position:0% +line so I don't know if this graphic +sort of helps you um kind of think about + + align:start position:0% +sort of helps you um kind of think about + + + align:start position:0% +sort of helps you um kind of think about +the relationship between a probability + + align:start position:0% +the relationship between a probability + + + align:start position:0% +the relationship between a probability +in a random variable in a sample space + + align:start position:0% +in a random variable in a sample space + + + align:start position:0% +in a random variable in a sample space +and and the unit interval and the real + + align:start position:0% +and and the unit interval and the real + + + align:start position:0% +and and the unit interval and the real +line it's all this is probably still + + align:start position:0% +line it's all this is probably still + + + align:start position:0% +line it's all this is probably still +abstra pretty abstract to you and we'll + + align:start position:0% +abstra pretty abstract to you and we'll + + + align:start position:0% +abstra pretty abstract to you and we'll +go through examples but at least for me + + align:start position:0% +go through examples but at least for me + + + align:start position:0% +go through examples but at least for me +this sort of this kind of GRA graic + + align:start position:0% +this sort of this kind of GRA graic + + + align:start position:0% +this sort of this kind of GRA graic +helps me think about what the difference + + align:start position:0% +helps me think about what the difference + + + align:start position:0% +helps me think about what the difference +between a probability like we defined + + align:start position:0% +between a probability like we defined + + + align:start position:0% +between a probability like we defined +last time is and a random variable so a + + align:start position:0% +last time is and a random variable so a + + + align:start position:0% +last time is and a random variable so a +probability goes from the set of all + + align:start position:0% +probability goes from the set of all + + + align:start position:0% +probability goes from the set of all +subsets of the sample space into the + + align:start position:0% +subsets of the sample space into the + + + align:start position:0% +subsets of the sample space into the +unit interval okay so it always has + + align:start position:0% +unit interval okay so it always has + + + align:start position:0% +unit interval okay so it always has +values between zero and one as we saw + + align:start position:0% +values between zero and one as we saw + + + align:start position:0% +values between zero and one as we saw +last time a random variable is um it's + + align:start position:0% +last time a random variable is um it's + + + align:start position:0% +last time a random variable is um it's +it goes from the sample space to the + + align:start position:0% +it goes from the sample space to the + + + align:start position:0% +it goes from the sample space to the +real line line and it's just some + + align:start position:0% +real line line and it's just some + + + align:start position:0% +real line line and it's just some +numerical characteristic of the sample + + align:start position:0% +numerical characteristic of the sample + + + align:start position:0% +numerical characteristic of the sample +space that we care about okay and the + + align:start position:0% +space that we care about okay and the + + + align:start position:0% +space that we care about okay and the +probability on the left + + align:start position:0% +probability on the left + + + align:start position:0% +probability on the left +induces the the the distribution of our + + align:start position:0% +induces the the the distribution of our + + + align:start position:0% +induces the the the distribution of our +random variable okay so I'll be more + + align:start position:0% +random variable okay so I'll be more + + + align:start position:0% +random variable okay so I'll be more +clear about that when we go through + + align:start position:0% +clear about that when we go through + + + align:start position:0% +clear about that when we go through +examples and and that will become much + + align:start position:0% +examples and and that will become much + + + align:start position:0% +examples and and that will become much +more concrete but basically we just + + align:start position:0% +more concrete but basically we just + + + align:start position:0% +more concrete but basically we just +think about um you know sort of the + + align:start position:0% +think about um you know sort of the + + + align:start position:0% +think about um you know sort of the +probability that exists that that's + + align:start position:0% +probability that exists that that's + + + align:start position:0% +probability that exists that that's +defined on this sample space as inducing + + align:start position:0% +defined on this sample space as inducing + + + align:start position:0% +defined on this sample space as inducing +a distribution of our random variable + + align:start position:0% +a distribution of our random variable + + + align:start position:0% +a distribution of our random variable +okay okay so all of the uh examples + + align:start position:0% +okay okay so all of the uh examples + + + align:start position:0% +okay okay so all of the uh examples +we've seen so far all of the probability + + align:start position:0% +we've seen so far all of the probability + + + align:start position:0% +we've seen so far all of the probability +examples uh would give rise to a type of + + align:start position:0% +examples uh would give rise to a type of + + + align:start position:0% +examples uh would give rise to a type of +random variable called discret okay and + + align:start position:0% +random variable called discret okay and + + + align:start position:0% +random variable called discret okay and +that's a t that's a random variable that + + align:start position:0% +that's a t that's a random variable that + + + align:start position:0% +that's a t that's a random variable that +takes on a finite or countably infinite + + align:start position:0% +takes on a finite or countably infinite + + + align:start position:0% +takes on a finite or countably infinite +number of + + align:start position:0% +number of + + + align:start position:0% +number of +values so uh the the examples that I + + align:start position:0% +values so uh the the examples that I + + + align:start position:0% +values so uh the the examples that I +gave you on the previous slide you know + + align:start position:0% +gave you on the previous slide you know + + + align:start position:0% +gave you on the previous slide you know +sort of the number of vegetarian + + align:start position:0% +sort of the number of vegetarian + + + align:start position:0% +sort of the number of vegetarian +toppings that I'm getting it's not going + + align:start position:0% +toppings that I'm getting it's not going + + + align:start position:0% +toppings that I'm getting it's not going +to be you know it's going to be uh an + + align:start position:0% +to be you know it's going to be uh an + + + align:start position:0% +to be you know it's going to be uh an +integer value for instance discrete + + align:start position:0% +integer value for instance discrete + + + align:start position:0% +integer value for instance discrete +random variables don't have to all be + + align:start position:0% +random variables don't have to all be + + + align:start position:0% +random variables don't have to all be +integers but uh something that can only + + align:start position:0% +integers but uh something that can only + + + align:start position:0% +integers but uh something that can only +take on the value of integers for + + align:start position:0% +take on the value of integers for + + + align:start position:0% +take on the value of integers for +instance would be a discrete random + + align:start position:0% +instance would be a discrete random + + + align:start position:0% +instance would be a discrete random +variable okay we can also however + + align:start position:0% +variable okay we can also however + + + align:start position:0% +variable okay we can also however +consider a natural generalization or + + align:start position:0% +consider a natural generalization or + + + align:start position:0% +consider a natural generalization or +kind of depending on the the + + align:start position:0% +kind of depending on the the + + + align:start position:0% +kind of depending on the the +mathematical framework you're using a + + align:start position:0% +mathematical framework you're using a + + + align:start position:0% +mathematical framework you're using a +different flavor of this + + align:start position:0% +different flavor of this + + + align:start position:0% +different flavor of this +construct and um and that's uh allowing + + align:start position:0% +construct and um and that's uh allowing + + + align:start position:0% +construct and um and that's uh allowing +a random variable to take on any value + + align:start position:0% +a random variable to take on any value + + + align:start position:0% +a random variable to take on any value +in some interval bounded or unbounded of + + align:start position:0% +in some interval bounded or unbounded of + + + align:start position:0% +in some interval bounded or unbounded of +the real line okay and this is called a + + align:start position:0% +the real line okay and this is called a + + + align:start position:0% +the real line okay and this is called a +continuous random variable so in this uh + + align:start position:0% +continuous random variable so in this uh + + + align:start position:0% +continuous random variable so in this uh +in this class and in most in a lot of + + align:start position:0% +in this class and in most in a lot of + + + align:start position:0% +in this class and in most in a lot of +Statistics classes in fact um we will + + align:start position:0% +Statistics classes in fact um we will + + + align:start position:0% +Statistics classes in fact um we will +mostly deal with uh continuous random + + align:start position:0% +mostly deal with uh continuous random + + + align:start position:0% +mostly deal with uh continuous random +variables and there are a couple reasons + + align:start position:0% +variables and there are a couple reasons + + + align:start position:0% +variables and there are a couple reasons +for this um this is partly because there + + align:start position:0% +for this um this is partly because there + + + align:start position:0% +for this um this is partly because there +are lots of discrete random variables in + + align:start position:0% +are lots of discrete random variables in + + + align:start position:0% +are lots of discrete random variables in +the real world that can be adequately + + align:start position:0% +the real world that can be adequately + + + align:start position:0% +the real world that can be adequately +approximated with continuous random + + align:start position:0% +approximated with continuous random + + + align:start position:0% +approximated with continuous random +variables okay and so then that that's + + align:start position:0% +variables okay and so then that that's + + + align:start position:0% +variables okay and so then that that's +uh sort of um handy if we're sort of uh + + align:start position:0% +uh sort of um handy if we're sort of uh + + + align:start position:0% +uh sort of um handy if we're sort of uh +we can do everything in the in the + + align:start position:0% +we can do everything in the in the + + + align:start position:0% +we can do everything in the in the +framework of a continuous random + + align:start position:0% +framework of a continuous random + + + align:start position:0% +framework of a continuous random +variable the other thing is that uh + + align:start position:0% +variable the other thing is that uh + + + align:start position:0% +variable the other thing is that uh +sometimes the the sort of math is just + + align:start position:0% +sometimes the the sort of math is just + + + align:start position:0% +sometimes the the sort of math is just +simply easier to do um when you're doing + + align:start position:0% +simply easier to do um when you're doing + + + align:start position:0% +simply easier to do um when you're doing +when you're considering um fun + + align:start position:0% +when you're considering um fun + + + align:start position:0% +when you're considering um fun +complicated functions of random + + align:start position:0% +complicated functions of random + + + align:start position:0% +complicated functions of random +variables uh for instance uh Sometimes + + align:start position:0% +variables uh for instance uh Sometimes + + + align:start position:0% +variables uh for instance uh Sometimes +using continuous random variables is + + align:start position:0% +using continuous random variables is + + + align:start position:0% +using continuous random variables is +just a lot lot simpler than uh doing + + align:start position:0% +just a lot lot simpler than uh doing + + + align:start position:0% +just a lot lot simpler than uh doing +everything with discret random + + align:start position:0% +everything with discret random + + + align:start position:0% +everything with discret random +variables okay so we will uh today we're + + align:start position:0% +variables okay so we will uh today we're + + + align:start position:0% +variables okay so we will uh today we're +going to see examples of discrete random + + align:start position:0% +going to see examples of discrete random + + + align:start position:0% +going to see examples of discrete random +variables continuous random variables + + align:start position:0% +variables continuous random variables + + + align:start position:0% +variables continuous random variables +and we'll continue to see them + + align:start position:0% +and we'll continue to see them + + + align:start position:0% +and we'll continue to see them +throughout the semester but as we go + + align:start position:0% +throughout the semester but as we go + + + align:start position:0% +throughout the semester but as we go +through the semester we'll see more and + + align:start position:0% +through the semester we'll see more and + + + align:start position:0% +through the semester we'll see more and +more examples of continuous random + + align:start position:0% +more examples of continuous random + + + align:start position:0% +more examples of continuous random +variables okay so um for discrete random + + align:start position:0% +variables okay so um for discrete random + + + align:start position:0% +variables okay so um for discrete random +variable we can often start with a + + align:start position:0% +variable we can often start with a + + + align:start position:0% +variable we can often start with a +verbal description and then BAS based on + + align:start position:0% +verbal description and then BAS based on + + + align:start position:0% +verbal description and then BAS based on +that verbal description a verbal + + align:start position:0% +that verbal description a verbal + + + align:start position:0% +that verbal description a verbal +description of some kind of an + + align:start position:0% +description of some kind of an + + + align:start position:0% +description of some kind of an +experiment and then based on that verbal + + align:start position:0% +experiment and then based on that verbal + + + align:start position:0% +experiment and then based on that verbal +description we can calculate + + align:start position:0% +description we can calculate + + + align:start position:0% +description we can calculate +probabilities for each value of the + + align:start position:0% +probabilities for each value of the + + + align:start position:0% +probabilities for each value of the +random + + align:start position:0% +random + + + align:start position:0% +random +variable and then write down a function + + align:start position:0% +variable and then write down a function + + + align:start position:0% +variable and then write down a function +or draw a graph or something like that + + align:start position:0% +or draw a graph or something like that + + + align:start position:0% +or draw a graph or something like that +that describes the probabilities for + + align:start position:0% +that describes the probabilities for + + + align:start position:0% +that describes the probabilities for +different values of the random variable + + align:start position:0% +different values of the random variable + + + align:start position:0% +different values of the random variable +and this is called a probability + + align:start position:0% +and this is called a probability + + + align:start position:0% +and this is called a probability +function now when last time when we saw + + align:start position:0% +function now when last time when we saw + + + align:start position:0% +function now when last time when we saw +the the + + align:start position:0% +the the + + + align:start position:0% +the the +hypergeometric uh example and the + + align:start position:0% +hypergeometric uh example and the + + + align:start position:0% +hypergeometric uh example and the +binomial example + + align:start position:0% +binomial example + + + align:start position:0% +binomial example +we did sort of the first part of this + + align:start position:0% +we did sort of the first part of this + + + align:start position:0% +we did sort of the first part of this +exercise already okay we didn't we + + align:start position:0% +exercise already okay we didn't we + + + align:start position:0% +exercise already okay we didn't we +hadn't defined random variables yet we + + align:start position:0% +hadn't defined random variables yet we + + + align:start position:0% +hadn't defined random variables yet we +did the first part of this exercise and + + align:start position:0% +did the first part of this exercise and + + + align:start position:0% +did the first part of this exercise and +so now the the two examples I'm going to + + align:start position:0% +so now the the two examples I'm going to + + + align:start position:0% +so now the the two examples I'm going to +do are sort of completing this exercise + + align:start position:0% +do are sort of completing this exercise + + + align:start position:0% +do are sort of completing this exercise +uh for um hyper geometric and binomial + + align:start position:0% +uh for um hyper geometric and binomial + + + align:start position:0% +uh for um hyper geometric and binomial +random variables okay so back to the + + align:start position:0% +random variables okay so back to the + + + align:start position:0% +random variables okay so back to the +pizza + + align:start position:0% +pizza + + + align:start position:0% +pizza +example so um we're going to define a + + align:start position:0% +example so um we're going to define a + + + align:start position:0% +example so um we're going to define a +random variable x and x is the number of + + align:start position:0% +random variable x and x is the number of + + + align:start position:0% +random variable x and x is the number of +vegetarian toppings I get on my pizza if + + align:start position:0% +vegetarian toppings I get on my pizza if + + + align:start position:0% +vegetarian toppings I get on my pizza if +I draw the area four toppings randomly + + align:start position:0% +I draw the area four toppings randomly + + + align:start position:0% +I draw the area four toppings randomly +without replacement okay so remember a + + align:start position:0% +without replacement okay so remember a + + + align:start position:0% +without replacement okay so remember a +random variable is some numerical + + align:start position:0% +random variable is some numerical + + + align:start position:0% +random variable is some numerical +characteristic of the sample space we + + align:start position:0% +characteristic of the sample space we + + + align:start position:0% +characteristic of the sample space we +care about in this case number of + + align:start position:0% +care about in this case number of + + + align:start position:0% +care about in this case number of +vegetarian toppings + + align:start position:0% +vegetarian toppings + + + align:start position:0% +vegetarian toppings +okay so last time we calculated the + + align:start position:0% +okay so last time we calculated the + + + align:start position:0% +okay so last time we calculated the +probability I can't remember exactly + + align:start position:0% +probability I can't remember exactly + + + align:start position:0% +probability I can't remember exactly +which probability we calculated the + + align:start position:0% +which probability we calculated the + + + align:start position:0% +which probability we calculated the +probability that I got one vegetarian + + align:start position:0% +probability that I got one vegetarian + + + align:start position:0% +probability that I got one vegetarian +topping when I drew two from R uh two + + align:start position:0% +topping when I drew two from R uh two + + + align:start position:0% +topping when I drew two from R uh two +two uh at random when there were six + + align:start position:0% +two uh at random when there were six + + + align:start position:0% +two uh at random when there were six +nonvegetarian and five vegetarian or + + align:start position:0% +nonvegetarian and five vegetarian or + + + align:start position:0% +nonvegetarian and five vegetarian or +something like that okay so we + + align:start position:0% +something like that okay so we + + + align:start position:0% +something like that okay so we +calculated that probability but what I + + align:start position:0% +calculated that probability but what I + + + align:start position:0% +calculated that probability but what I +want to do now is I want to calculate + + align:start position:0% +want to do now is I want to calculate + + + align:start position:0% +want to do now is I want to calculate +those probabilities for all of the the + + align:start position:0% +those probabilities for all of the the + + + align:start position:0% +those probabilities for all of the the +various possible values of X okay so + + align:start position:0% +various possible values of X okay so + + + align:start position:0% +various possible values of X okay so +instead of just saying what's the + + align:start position:0% +instead of just saying what's the + + + align:start position:0% +instead of just saying what's the +probability that I get one vegetarian + + align:start position:0% +probability that I get one vegetarian + + + align:start position:0% +probability that I get one vegetarian +topping I want to calculate the + + align:start position:0% +topping I want to calculate the + + + align:start position:0% +topping I want to calculate the +probability that I get zero that I get + + align:start position:0% +probability that I get zero that I get + + + align:start position:0% +probability that I get zero that I get +one that I get two and so forth up to + + align:start position:0% +one that I get two and so forth up to + + + align:start position:0% +one that I get two and so forth up to +the maximum number of uh vegetan Aran + + align:start position:0% +the maximum number of uh vegetan Aran + + + align:start position:0% +the maximum number of uh vegetan Aran +topics I can get okay and in this case + + align:start position:0% +topics I can get okay and in this case + + + align:start position:0% +topics I can get okay and in this case +the maximum number is the max of six and + + align:start position:0% +the maximum number is the max of six and + + + align:start position:0% +the maximum number is the max of six and +N why is + + align:start position:0% + + + + align:start position:0% + +that so perhaps you don't remember what + + align:start position:0% +that so perhaps you don't remember what + + + align:start position:0% +that so perhaps you don't remember what +um sort of how what the setup of this + + align:start position:0% +um sort of how what the setup of this + + + align:start position:0% +um sort of how what the setup of this +problem was six is the number of + + align:start position:0% +problem was six is the number of + + + align:start position:0% +problem was six is the number of +vegetarian toppings available so I can't + + align:start position:0% +vegetarian toppings available so I can't + + + align:start position:0% +vegetarian toppings available so I can't +get any more than that n is the number + + align:start position:0% +get any more than that n is the number + + + align:start position:0% +get any more than that n is the number +of toppings that I'm choosing at random + + align:start position:0% +of toppings that I'm choosing at random + + + align:start position:0% +of toppings that I'm choosing at random +so I can't get any more than that okay + + align:start position:0% +so I can't get any more than that okay + + + align:start position:0% +so I can't get any more than that okay +so the the um oh sorry up to a sorry the + + align:start position:0% +so the the um oh sorry up to a sorry the + + + align:start position:0% +so the the um oh sorry up to a sorry the +minimum or yeah the the it it yeah the + + align:start position:0% +minimum or yeah the the it it yeah the + + + align:start position:0% +minimum or yeah the the it it yeah the +minimum of of six and N + + align:start position:0% +minimum of of six and N + + + align:start position:0% +minimum of of six and N +okay or yeah sorry I guess I wrote this + + align:start position:0% +okay or yeah sorry I guess I wrote this + + + align:start position:0% +okay or yeah sorry I guess I wrote this +in a somewhat confusing way but I think + + align:start position:0% +in a somewhat confusing way but I think + + + align:start position:0% +in a somewhat confusing way but I think +it's it's actually correct up there so + + align:start position:0% +it's it's actually correct up there so + + + align:start position:0% +it's it's actually correct up there so +up to six or n whichever is + + align:start position:0% +up to six or n whichever is + + + align:start position:0% +up to six or n whichever is +smaller okay so I use this + + align:start position:0% +smaller okay so I use this + + + align:start position:0% +smaller okay so I use this +formula and couple things to note about + + align:start position:0% +formula and couple things to note about + + + align:start position:0% +formula and couple things to note about +it it's a little bit different from the + + align:start position:0% +it it's a little bit different from the + + + align:start position:0% +it it's a little bit different from the +one I had up on the uh screen last time + + align:start position:0% +one I had up on the uh screen last time + + + align:start position:0% +one I had up on the uh screen last time +um first of all I CH well I changed the + + align:start position:0% +um first of all I CH well I changed the + + + align:start position:0% +um first of all I CH well I changed the +notation first of all I changed N1 to X + + align:start position:0% +notation first of all I changed N1 to X + + + align:start position:0% +notation first of all I changed N1 to X +okay and that's just to be uh consistent + + align:start position:0% +okay and that's just to be uh consistent + + + align:start position:0% +okay and that's just to be uh consistent +with my notation for the random variable + + align:start position:0% +with my notation for the random variable + + + align:start position:0% +with my notation for the random variable +and then I noted that uh N1 plus N2 was + + align:start position:0% +and then I noted that uh N1 plus N2 was + + + align:start position:0% +and then I noted that uh N1 plus N2 was +equal to n and so then I just uh since I + + align:start position:0% +equal to n and so then I just uh since I + + + align:start position:0% +equal to n and so then I just uh since I +substituted X for N1 then I just + + align:start position:0% +substituted X for N1 then I just + + + align:start position:0% +substituted X for N1 then I just +substituted n minus X for N2 + + align:start position:0% +substituted n minus X for N2 + + + align:start position:0% +substituted n minus X for N2 +okay so just change the notation a + + align:start position:0% +okay so just change the notation a + + + align:start position:0% +okay so just change the notation a +little bit otherwise it's exactly the + + align:start position:0% +little bit otherwise it's exactly the + + + align:start position:0% +little bit otherwise it's exactly the +same formula and then the other thing I + + align:start position:0% +same formula and then the other thing I + + + align:start position:0% +same formula and then the other thing I +want to note that I forgot to note last + + align:start position:0% +want to note that I forgot to note last + + + align:start position:0% +want to note that I forgot to note last +time is that zero factorial is defined + + align:start position:0% +time is that zero factorial is defined + + + align:start position:0% +time is that zero factorial is defined +as one so when we're using this formula + + align:start position:0% +as one so when we're using this formula + + + align:start position:0% +as one so when we're using this formula +and we're plugging in for x equals 0 + + align:start position:0% +and we're plugging in for x equals 0 + + + align:start position:0% +and we're plugging in for x equals 0 +it's no problem + + align:start position:0% +it's no problem + + + align:start position:0% +it's no problem +okay okay so I go ahead and do that for + + align:start position:0% +okay okay so I go ahead and do that for + + + align:start position:0% +okay okay so I go ahead and do that for +all of the possible values of + + align:start position:0% +all of the possible values of + + + align:start position:0% +all of the possible values of +X of course they're going to be + + align:start position:0% +X of course they're going to be + + + align:start position:0% +X of course they're going to be +functions of n in general but for + + align:start position:0% +functions of n in general but for + + + align:start position:0% +functions of n in general but for +concreteness let me choose a particular + + align:start position:0% +concreteness let me choose a particular + + + align:start position:0% +concreteness let me choose a particular +n so we'll choose n equals 3 so we've + + align:start position:0% +n so we'll choose n equals 3 so we've + + + align:start position:0% +n so we'll choose n equals 3 so we've +got the probability that X is equal to Z + + align:start position:0% +got the probability that X is equal to Z + + + align:start position:0% +got the probability that X is equal to Z +is uh equal when n is three is equal to + + align:start position:0% +is uh equal when n is three is equal to + + + align:start position:0% +is uh equal when n is three is equal to +6 over + + align:start position:0% +6 over + + + align:start position:0% +6 over +99 and then so forth um 36 over 99 for + + align:start position:0% +99 and then so forth um 36 over 99 for + + + align:start position:0% +99 and then so forth um 36 over 99 for +xals one and um and on + + align:start position:0% + + + + align:start position:0% + +okay and here is a picture of sort of + + align:start position:0% +okay and here is a picture of sort of + + + align:start position:0% +okay and here is a picture of sort of +graphically what this probability + + align:start position:0% +graphically what this probability + + + align:start position:0% +graphically what this probability +function looks like okay so here on the + + align:start position:0% +function looks like okay so here on the + + + align:start position:0% +function looks like okay so here on the +uh horizontal axis I have the different + + align:start position:0% +uh horizontal axis I have the different + + + align:start position:0% +uh horizontal axis I have the different +values that X can take on and then I + + align:start position:0% +values that X can take on and then I + + + align:start position:0% +values that X can take on and then I +have uh the um the probabilities with + + align:start position:0% +have uh the um the probabilities with + + + align:start position:0% +have uh the um the probabilities with +which uh the random variable X takes on + + align:start position:0% +which uh the random variable X takes on + + + align:start position:0% +which uh the random variable X takes on +those + + align:start position:0% +those + + + align:start position:0% +those +values + + align:start position:0% +values + + + align:start position:0% +values +okay so uh one thing I want to pause for + + align:start position:0% +okay so uh one thing I want to pause for + + + align:start position:0% +okay so uh one thing I want to pause for +just a second and note um a couple + + align:start position:0% +just a second and note um a couple + + + align:start position:0% +just a second and note um a couple +things about uh about this graph so by + + align:start position:0% +things about uh about this graph so by + + + align:start position:0% +things about uh about this graph so by +con vention we graph um when we graph + + align:start position:0% +con vention we graph um when we graph + + + align:start position:0% +con vention we graph um when we graph +probability functions we put vertical + + align:start position:0% +probability functions we put vertical + + + align:start position:0% +probability functions we put vertical +lines beneath each um point on the graph + + align:start position:0% +lines beneath each um point on the graph + + + align:start position:0% +lines beneath each um point on the graph +okay and I suppose that just makes them + + align:start position:0% +okay and I suppose that just makes them + + + align:start position:0% +okay and I suppose that just makes them +easier to read but in probability that's + + align:start position:0% +easier to read but in probability that's + + + align:start position:0% +easier to read but in probability that's +sort of a very standard convention + + align:start position:0% +sort of a very standard convention + + + align:start position:0% +sort of a very standard convention +you'll see these sort of vertical lines + + align:start position:0% +you'll see these sort of vertical lines + + + align:start position:0% +you'll see these sort of vertical lines +instead of just dots on the graph and + + align:start position:0% +instead of just dots on the graph and + + + align:start position:0% +instead of just dots on the graph and +then also a a piece of terminology that + + align:start position:0% +then also a a piece of terminology that + + + align:start position:0% +then also a a piece of terminology that +you should know is that each one of + + align:start position:0% +you should know is that each one of + + + align:start position:0% +you should know is that each one of +these points is called a point + + align:start position:0% +these points is called a point + + + align:start position:0% +these points is called a point +Mass okay + + align:start position:0% + + + + align:start position:0% + +okay any questions what we've done here + + align:start position:0% +okay any questions what we've done here + + + align:start position:0% +okay any questions what we've done here +so this is a pretty this is a a pretty + + align:start position:0% +so this is a pretty this is a a pretty + + + align:start position:0% +so this is a pretty this is a a pretty +important thing to understand we started + + align:start position:0% +important thing to understand we started + + + align:start position:0% +important thing to understand we started +from this verbal description of like + + align:start position:0% +from this verbal description of like + + + align:start position:0% +from this verbal description of like +drawing pieces of paper out of a hat and + + align:start position:0% +drawing pieces of paper out of a hat and + + + align:start position:0% +drawing pieces of paper out of a hat and +you know that have uh different pizza + + align:start position:0% +you know that have uh different pizza + + + align:start position:0% +you know that have uh different pizza +toppings on it and from that we were + + align:start position:0% +toppings on it and from that we were + + + align:start position:0% +toppings on it and from that we were +able to write down the probability + + align:start position:0% +able to write down the probability + + + align:start position:0% +able to write down the probability +function of a random variable that we + + align:start position:0% +function of a random variable that we + + + align:start position:0% +function of a random variable that we +defined on that sample + + align:start position:0% +defined on that sample + + + align:start position:0% +defined on that sample +space does that make sense okay + + align:start position:0% +space does that make sense okay + + + align:start position:0% +space does that make sense okay +so we can do this uh in a more General + + align:start position:0% +so we can do this uh in a more General + + + align:start position:0% +so we can do this uh in a more General +way okay so I had I picked the specific + + align:start position:0% +way okay so I had I picked the specific + + + align:start position:0% +way okay so I had I picked the specific +example of the the area 4 menu and that + + align:start position:0% +example of the the area 4 menu and that + + + align:start position:0% +example of the the area 4 menu and that +sort of let us calculate actual you know + + align:start position:0% +sort of let us calculate actual you know + + + align:start position:0% +sort of let us calculate actual you know +sort of numerical values for our + + align:start position:0% +sort of numerical values for our + + + align:start position:0% +sort of numerical values for our +probability function um but it's also + + align:start position:0% +probability function um but it's also + + + align:start position:0% +probability function um but it's also +useful to recognize that this is a + + align:start position:0% +useful to recognize that this is a + + + align:start position:0% +useful to recognize that this is a +general type of um this is a general + + align:start position:0% +general type of um this is a general + + + align:start position:0% +general type of um this is a general +type of uh uh random variable that you + + align:start position:0% +type of uh uh random variable that you + + + align:start position:0% +type of uh uh random variable that you +might run into again okay and and um we + + align:start position:0% +might run into again okay and and um we + + + align:start position:0% +might run into again okay and and um we +call it in particular a hyper geometric + + align:start position:0% +call it in particular a hyper geometric + + + align:start position:0% +call it in particular a hyper geometric +U random variable so we say that X has a + + align:start position:0% +U random variable so we say that X has a + + + align:start position:0% +U random variable so we say that X has a +hyper geometric distribution with + + align:start position:0% +hyper geometric distribution with + + + align:start position:0% +hyper geometric distribution with +parameters capital N where capital N is + + align:start position:0% +parameters capital N where capital N is + + + align:start position:0% +parameters capital N where capital N is +in our case the total number of toppings + + align:start position:0% +in our case the total number of toppings + + + align:start position:0% +in our case the total number of toppings +available for the pizza capital K the + + align:start position:0% +available for the pizza capital K the + + + align:start position:0% +available for the pizza capital K the +total number of vegetarian toppings and + + align:start position:0% +total number of vegetarian toppings and + + + align:start position:0% +total number of vegetarian toppings and +little n the number that we're going to + + align:start position:0% +little n the number that we're going to + + + align:start position:0% +little n the number that we're going to +choose okay so does this make sense to + + align:start position:0% +choose okay so does this make sense to + + + align:start position:0% +choose okay so does this make sense to +everyone is this clear + + align:start position:0% +everyone is this clear + + + align:start position:0% +everyone is this clear +and then afterwards we have to be be + + align:start position:0% +and then afterwards we have to be be + + + align:start position:0% +and then afterwards we have to be be +sure to um note for which values of um + + align:start position:0% +sure to um note for which values of um + + + align:start position:0% +sure to um note for which values of um +for which values of X that there is + + align:start position:0% +for which values of X that there is + + + align:start position:0% +for which values of X that there is +positive probability so for which values + + align:start position:0% +positive probability so for which values + + + align:start position:0% +positive probability so for which values +of X this is the formula to compute the + + align:start position:0% +of X this is the formula to compute the + + + align:start position:0% +of X this is the formula to compute the +the + + align:start position:0% +the + + + align:start position:0% +the +probability okay and I've been a little + + align:start position:0% +probability okay and I've been a little + + + align:start position:0% +probability okay and I've been a little +lazy here if I wanted to be + + align:start position:0% +lazy here if I wanted to be + + + align:start position:0% +lazy here if I wanted to be +absolutely um correct I would have have + + align:start position:0% +absolutely um correct I would have have + + + align:start position:0% +absolutely um correct I would have have +written this as f ofx f subx of little X + + align:start position:0% +written this as f ofx f subx of little X + + + align:start position:0% +written this as f ofx f subx of little X +is equal to this formula for these + + align:start position:0% +is equal to this formula for these + + + align:start position:0% +is equal to this formula for these +values of X and it's equal to zero + + align:start position:0% +values of X and it's equal to zero + + + align:start position:0% +values of X and it's equal to zero +otherwise okay sometimes we leave off + + align:start position:0% +otherwise okay sometimes we leave off + + + align:start position:0% +otherwise okay sometimes we leave off +the equals zero otherwise just because + + align:start position:0% +the equals zero otherwise just because + + + align:start position:0% +the equals zero otherwise just because +we're lazy but it's sort of uh + + align:start position:0% +we're lazy but it's sort of uh + + + align:start position:0% +we're lazy but it's sort of uh +understood + + align:start position:0% +understood + + + align:start position:0% +understood +okay okay so what can we say what how + + align:start position:0% +okay okay so what can we say what how + + + align:start position:0% +okay okay so what can we say what how +how do we interpret this um distribution + + align:start position:0% +how do we interpret this um distribution + + + align:start position:0% +how do we interpret this um distribution +sometimes it is useful to think in terms + + align:start position:0% +sometimes it is useful to think in terms + + + align:start position:0% +sometimes it is useful to think in terms +of you know to think in terms of of uh + + align:start position:0% +of you know to think in terms of of uh + + + align:start position:0% +of you know to think in terms of of uh +you know a description of a an + + align:start position:0% +you know a description of a an + + + align:start position:0% +you know a description of a an +experiment or something like that when + + align:start position:0% +experiment or something like that when + + + align:start position:0% +experiment or something like that when +we're thinking about uh random variables + + align:start position:0% +we're thinking about uh random variables + + + align:start position:0% +we're thinking about uh random variables +and the interpretation I put on the + + align:start position:0% +and the interpretation I put on the + + + align:start position:0% +and the interpretation I put on the +hypergeometric is that it describes the + + align:start position:0% +hypergeometric is that it describes the + + + align:start position:0% +hypergeometric is that it describes the +number of quote successes in end trials + + align:start position:0% +number of quote successes in end trials + + + align:start position:0% +number of quote successes in end trials +when you're sampling without replacement + + align:start position:0% +when you're sampling without replacement + + + align:start position:0% +when you're sampling without replacement +from a sample of size n whose initial + + align:start position:0% +from a sample of size n whose initial + + + align:start position:0% +from a sample of size n whose initial +probability is K Over N okay so sampling + + align:start position:0% +probability is K Over N okay so sampling + + + align:start position:0% +probability is K Over N okay so sampling +without replacement we're not putting + + align:start position:0% +without replacement we're not putting + + + align:start position:0% +without replacement we're not putting +the pieces of paper back in the Hat we + + align:start position:0% +the pieces of paper back in the Hat we + + + align:start position:0% +the pieces of paper back in the Hat we +pull them out and we read them and then + + align:start position:0% +pull them out and we read them and then + + + align:start position:0% +pull them out and we read them and then +that's it and the sample the initial + + align:start position:0% +that's it and the sample the initial + + + align:start position:0% +that's it and the sample the initial +sample sizes in and the initial + + align:start position:0% +sample sizes in and the initial + + + align:start position:0% +sample sizes in and the initial +probability of success in in our case a + + align:start position:0% +probability of success in in our case a + + + align:start position:0% +probability of success in in our case a +quote Success is defined as a vegetarian + + align:start position:0% +quote Success is defined as a vegetarian + + + align:start position:0% +quote Success is defined as a vegetarian +topping so the the initial probability + + align:start position:0% +topping so the the initial probability + + + align:start position:0% +topping so the the initial probability +of success is K Over N and then of + + align:start position:0% +of success is K Over N and then of + + + align:start position:0% +of success is K Over N and then of +course that probability of success + + align:start position:0% +course that probability of success + + + align:start position:0% +course that probability of success +changes uh over the course of the + + align:start position:0% +changes uh over the course of the + + + align:start position:0% +changes uh over the course of the +experiment as you're drawing without + + align:start position:0% +experiment as you're drawing without + + + align:start position:0% +experiment as you're drawing without +replacement okay + + align:start position:0% + + + + align:start position:0% + +yep again + + align:start position:0% +yep again + + + align:start position:0% +yep again +notations what does that okay so it + + align:start position:0% +notations what does that okay so it + + + align:start position:0% +notations what does that okay so it +means that the the these are the values + + align:start position:0% +means that the the these are the values + + + align:start position:0% +means that the the these are the values +for which um X has positive probability + + align:start position:0% +for which um X has positive probability + + + align:start position:0% +for which um X has positive probability +okay so um it can't obviously um you + + align:start position:0% +okay so um it can't obviously um you + + + align:start position:0% +okay so um it can't obviously um you +know have positive probability for + + align:start position:0% +know have positive probability for + + + align:start position:0% +know have positive probability for +anything less than zero and it can't it + + align:start position:0% +anything less than zero and it can't it + + + align:start position:0% +anything less than zero and it can't it +also can't have positive probability if + + align:start position:0% +also can't have positive probability if + + + align:start position:0% +also can't have positive probability if +if uh let me see n + K minus n so if + + align:start position:0% +if uh let me see n + K minus n so if + + + align:start position:0% +if uh let me see n + K minus n so if +Capital if the number vegetarian + + align:start position:0% +Capital if the number vegetarian + + + align:start position:0% +Capital if the number vegetarian +toppings plus the number that you + + align:start position:0% + + + + align:start position:0% + +choose minus let me think through this + + align:start position:0% +choose minus let me think through this + + + align:start position:0% +choose minus let me think through this +so the number you choose plus the number + + align:start position:0% +so the number you choose plus the number + + + align:start position:0% +so the number you choose plus the number +of vegetarian toppings minus n is + + align:start position:0% +of vegetarian toppings minus n is + + + align:start position:0% +of vegetarian toppings minus n is +positive then that's the that's the um + + align:start position:0% +positive then that's the that's the um + + + align:start position:0% +positive then that's the that's the um +minimum that the uh X can take on okay + + align:start position:0% +minimum that the uh X can take on okay + + + align:start position:0% +minimum that the uh X can take on okay +and then it it the maximum it can take + + align:start position:0% +and then it it the maximum it can take + + + align:start position:0% +and then it it the maximum it can take +on is either the number of vegetarian + + align:start position:0% +on is either the number of vegetarian + + + align:start position:0% +on is either the number of vegetarian +toppings you're choosing or sorry the + + align:start position:0% +toppings you're choosing or sorry the + + + align:start position:0% +toppings you're choosing or sorry the +number of toppings you're choosing or + + align:start position:0% +number of toppings you're choosing or + + + align:start position:0% +number of toppings you're choosing or +the total number of vegetarian toppings + + align:start position:0% +the total number of vegetarian toppings + + + align:start position:0% +the total number of vegetarian toppings +it can't exceed either of + + align:start position:0% +it can't exceed either of + + + align:start position:0% +it can't exceed either of +those + + align:start position:0% + + + + align:start position:0% + +okay okay + + align:start position:0% + + + + align:start position:0% + +questions okay second + + align:start position:0% +questions okay second + + + align:start position:0% +questions okay second +example so um remember that we had in + + align:start position:0% +example so um remember that we had in + + + align:start position:0% +example so um remember that we had in +the staff Curry example we did last time + + align:start position:0% +the staff Curry example we did last time + + + align:start position:0% +the staff Curry example we did last time +uh we talked about how we could uh think + + align:start position:0% +uh we talked about how we could uh think + + + align:start position:0% +uh we talked about how we could uh think +about the number of shots he made the + + align:start position:0% +about the number of shots he made the + + + align:start position:0% +about the number of shots he made the +number of threo uh shots that he made as + + align:start position:0% +number of threo uh shots that he made as + + + align:start position:0% +number of threo uh shots that he made as +having a binomial distribution if we + + align:start position:0% +having a binomial distribution if we + + + align:start position:0% +having a binomial distribution if we +made certain assumptions such as the + + align:start position:0% +made certain assumptions such as the + + + align:start position:0% +made certain assumptions such as the +shots were independent and the + + align:start position:0% +shots were independent and the + + + align:start position:0% +shots were independent and the +probability of making each shot uh was + + align:start position:0% +probability of making each shot uh was + + + align:start position:0% +probability of making each shot uh was +the same uh for for each shot okay so + + align:start position:0% +the same uh for for each shot okay so + + + align:start position:0% +the same uh for for each shot okay so +let's now Define a random variable + + align:start position:0% +let's now Define a random variable + + + align:start position:0% +let's now Define a random variable +that's based on this sort of um + + align:start position:0% +that's based on this sort of um + + + align:start position:0% +that's based on this sort of um +experiment and we'll call this random + + align:start position:0% +experiment and we'll call this random + + + align:start position:0% +experiment and we'll call this random +variable X as well and let it be the + + align:start position:0% +variable X as well and let it be the + + + align:start position:0% +variable X as well and let it be the +number of three-point shots that Steph + + align:start position:0% +number of three-point shots that Steph + + + align:start position:0% +number of three-point shots that Steph +Curry makes in the next six shots he + + align:start position:0% +Curry makes in the next six shots he + + + align:start position:0% +Curry makes in the next six shots he +takes + + align:start position:0% +takes + + + align:start position:0% +takes +okay so just like we did in the previous + + align:start position:0% +okay so just like we did in the previous + + + align:start position:0% +okay so just like we did in the previous +example we can calculate the probability + + align:start position:0% +example we can calculate the probability + + + align:start position:0% +example we can calculate the probability +that x equals 0 x x = 1 x = 2 and so + + align:start position:0% +that x equals 0 x x = 1 x = 2 and so + + + align:start position:0% +that x equals 0 x x = 1 x = 2 and so +forth up to six and we actually + + align:start position:0% +forth up to six and we actually + + + align:start position:0% +forth up to six and we actually +calculated a couple of those last time + + align:start position:0% +calculated a couple of those last time + + + align:start position:0% +calculated a couple of those last time +two or three of them last time in the + + align:start position:0% +two or three of them last time in the + + + align:start position:0% +two or three of them last time in the +example uh but we can we have a formula + + align:start position:0% +example uh but we can we have a formula + + + align:start position:0% +example uh but we can we have a formula +here 6 choose x uh time 44 to the x * + + align:start position:0% +here 6 choose x uh time 44 to the x * + + + align:start position:0% +here 6 choose x uh time 44 to the x * +.56 6 - x and remember where this comes + + align:start position:0% +.56 6 - x and remember where this comes + + + align:start position:0% +.56 6 - x and remember where this comes +from this is the probability that he + + align:start position:0% +from this is the probability that he + + + align:start position:0% +from this is the probability that he +makes any particular shot this is the + + align:start position:0% +makes any particular shot this is the + + + align:start position:0% +makes any particular shot this is the +probability that he misses any + + align:start position:0% +probability that he misses any + + + align:start position:0% +probability that he misses any +particular shot this is + + align:start position:0% +particular shot this is + + + align:start position:0% +particular shot this is +the without this uh coefficient out + + align:start position:0% +the without this uh coefficient out + + + align:start position:0% +the without this uh coefficient out +front that's the probability of any + + align:start position:0% +front that's the probability of any + + + align:start position:0% +front that's the probability of any +particular sequence of X um shots made + + align:start position:0% +particular sequence of X um shots made + + + align:start position:0% +particular sequence of X um shots made +and 6 - x shots missed and then if we + + align:start position:0% +and 6 - x shots missed and then if we + + + align:start position:0% +and 6 - x shots missed and then if we +add this coefficient out in the front + + align:start position:0% +add this coefficient out in the front + + + align:start position:0% +add this coefficient out in the front +that tells us the that counts the number + + align:start position:0% +that tells us the that counts the number + + + align:start position:0% +that tells us the that counts the number +of such sequences there are okay so you + + align:start position:0% +of such sequences there are okay so you + + + align:start position:0% +of such sequences there are okay so you +guys remember this from last time so we + + align:start position:0% +guys remember this from last time so we + + + align:start position:0% +guys remember this from last time so we +just use this formula we plug into it to + + align:start position:0% +just use this formula we plug into it to + + + align:start position:0% +just use this formula we plug into it to +calculate the probabilities for all of + + align:start position:0% +calculate the probabilities for all of + + + align:start position:0% +calculate the probabilities for all of +the various values of + + align:start position:0% + + + + align:start position:0% + +X + + align:start position:0% +X + + + align:start position:0% +X +Okay and like I said some of these look + + align:start position:0% +Okay and like I said some of these look + + + align:start position:0% +Okay and like I said some of these look +probably look familiar because we + + align:start position:0% +probably look familiar because we + + + align:start position:0% +probably look familiar because we +calculated them last time I think we + + align:start position:0% +calculated them last time I think we + + + align:start position:0% +calculated them last time I think we +calculated the probability that x equals + + align:start position:0% +calculated the probability that x equals + + + align:start position:0% +calculated the probability that x equals +3 last time and maybe we calculated the + + align:start position:0% +3 last time and maybe we calculated the + + + align:start position:0% +3 last time and maybe we calculated the +probability that x equals z last time I + + align:start position:0% +probability that x equals z last time I + + + align:start position:0% +probability that x equals z last time I +can't + + align:start position:0% +can't + + + align:start position:0% +can't +remember + + align:start position:0% +remember + + + align:start position:0% +remember +okay so graphically what does this look + + align:start position:0% +okay so graphically what does this look + + + align:start position:0% +okay so graphically what does this look +like there we go and again I sort of + + align:start position:0% +like there we go and again I sort of + + + align:start position:0% +like there we go and again I sort of +graphed each point Mass as you know sort + + align:start position:0% +graphed each point Mass as you know sort + + + align:start position:0% +graphed each point Mass as you know sort +of a DOT and a sort of a vertical line + + align:start position:0% +of a DOT and a sort of a vertical line + + + align:start position:0% +of a DOT and a sort of a vertical line +under it now if you just glance at this + + align:start position:0% +under it now if you just glance at this + + + align:start position:0% +under it now if you just glance at this +you might think it's uh symmetric this + + align:start position:0% +you might think it's uh symmetric this + + + align:start position:0% +you might think it's uh symmetric this +distribution symmetric but in fact it's + + align:start position:0% +distribution symmetric but in fact it's + + + align:start position:0% +distribution symmetric but in fact it's +not I mean if you look at the numbers + + align:start position:0% +not I mean if you look at the numbers + + + align:start position:0% +not I mean if you look at the numbers +you can tell it's not and if if you look + + align:start position:0% +you can tell it's not and if if you look + + + align:start position:0% +you can tell it's not and if if you look +closely at my drawing you can also tell + + align:start position:0% +closely at my drawing you can also tell + + + align:start position:0% +closely at my drawing you can also tell +it's not + + align:start position:0% +it's not + + + align:start position:0% +it's not +um okay and again just like in the last + + align:start position:0% +um okay and again just like in the last + + + align:start position:0% +um okay and again just like in the last +example we can sort of generalize this + + align:start position:0% +example we can sort of generalize this + + + align:start position:0% +example we can sort of generalize this +example so we can say uh instead of + + align:start position:0% +example so we can say uh instead of + + + align:start position:0% +example so we can say uh instead of +uh just uh considering um events where + + align:start position:0% +uh just uh considering um events where + + + align:start position:0% +uh just uh considering um events where +there's a a0 44 probability of a success + + align:start position:0% +there's a a0 44 probability of a success + + + align:start position:0% +there's a a0 44 probability of a success +and a 0.56 probability of a failure we + + align:start position:0% +and a 0.56 probability of a failure we + + + align:start position:0% +and a 0.56 probability of a failure we +can sort of uh use more General notation + + align:start position:0% +can sort of uh use more General notation + + + align:start position:0% +can sort of uh use more General notation +and consider um arbitrary probability of + + align:start position:0% +and consider um arbitrary probability of + + + align:start position:0% +and consider um arbitrary probability of +success as p and also consider an + + align:start position:0% +success as p and also consider an + + + align:start position:0% +success as p and also consider an +arbitrary number of Trials n okay so we + + align:start position:0% +arbitrary number of Trials n okay so we + + + align:start position:0% +arbitrary number of Trials n okay so we +say that uh X has a binomial + + align:start position:0% +say that uh X has a binomial + + + align:start position:0% +say that uh X has a binomial +distribution with parameters n and p + + align:start position:0% +distribution with parameters n and p + + + align:start position:0% +distribution with parameters n and p +and um that's uh denoted using that + + align:start position:0% +and um that's uh denoted using that + + + align:start position:0% +and um that's uh denoted using that +notation okay and then its probability + + align:start position:0% +notation okay and then its probability + + + align:start position:0% +notation okay and then its probability +function looks like this and again I was + + align:start position:0% +function looks like this and again I was + + + align:start position:0% +function looks like this and again I was +sort of uh you know I was too lazy to + + align:start position:0% +sort of uh you know I was too lazy to + + + align:start position:0% +sort of uh you know I was too lazy to +put equals zero otherwise but that's + + align:start position:0% +put equals zero otherwise but that's + + + align:start position:0% +put equals zero otherwise but that's +understood okay does this make sense do + + align:start position:0% +understood okay does this make sense do + + + align:start position:0% +understood okay does this make sense do +do you guys given these two examples do + + align:start position:0% +do you guys given these two examples do + + + align:start position:0% +do you guys given these two examples do +you feel like you have a little bit of a + + align:start position:0% +you feel like you have a little bit of a + + + align:start position:0% +you feel like you have a little bit of a +sense about what a random variable is a + + align:start position:0% +sense about what a random variable is a + + + align:start position:0% +sense about what a random variable is a +little bit of + + align:start position:0% +little bit of + + + align:start position:0% +little bit of +intuition + + align:start position:0% +intuition + + + align:start position:0% +intuition +okay okay but do feel free as I said to + + align:start position:0% +okay okay but do feel free as I said to + + + align:start position:0% +okay okay but do feel free as I said to +stop and ask questions if if we're going + + align:start position:0% +stop and ask questions if if we're going + + + align:start position:0% +stop and ask questions if if we're going +through this material too + + align:start position:0% + + + + align:start position:0% + +quickly okay so the binomial + + align:start position:0% +quickly okay so the binomial + + + align:start position:0% +quickly okay so the binomial +distribution comes up a + + align:start position:0% +distribution comes up a + + + align:start position:0% +distribution comes up a +lot and um it's it's also it can be very + + align:start position:0% +lot and um it's it's also it can be very + + + align:start position:0% +lot and um it's it's also it can be very +useful in lots of different settings uh + + align:start position:0% +useful in lots of different settings uh + + + align:start position:0% +useful in lots of different settings uh +here's a picture of several different um + + align:start position:0% +here's a picture of several different um + + + align:start position:0% +here's a picture of several different um +probability functions from uh binomial + + align:start position:0% +probability functions from uh binomial + + + align:start position:0% +probability functions from uh binomial +distributions with different parameters + + align:start position:0% +distributions with different parameters + + + align:start position:0% +distributions with different parameters +so this picture all in this picture all + + align:start position:0% +so this picture all in this picture all + + + align:start position:0% +so this picture all in this picture all +of the parameters all of the P + + align:start position:0% +of the parameters all of the P + + + align:start position:0% +of the parameters all of the P +parameters are equal to 0.5 so if p is + + align:start position:0% +parameters are equal to 0.5 so if p is + + + align:start position:0% +parameters are equal to 0.5 so if p is +equal to 0.5 you will in fact get a + + align:start position:0% +equal to 0.5 you will in fact get a + + + align:start position:0% +equal to 0.5 you will in fact get a +symmetric distribution if p is not equal + + align:start position:0% +symmetric distribution if p is not equal + + + align:start position:0% +symmetric distribution if p is not equal +to 0.5 you won't get a symmetric + + align:start position:0% +to 0.5 you won't get a symmetric + + + align:start position:0% +to 0.5 you won't get a symmetric +distribution so here all of these PS are + + align:start position:0% +distribution so here all of these PS are + + + align:start position:0% +distribution so here all of these PS are +equal to 0.5 and then you can see how + + align:start position:0% +equal to 0.5 and then you can see how + + + align:start position:0% +equal to 0.5 and then you can see how +the distribution changes as uh n + + align:start position:0% +the distribution changes as uh n + + + align:start position:0% +the distribution changes as uh n +increases + + align:start position:0% + + + + align:start position:0% + +okay and that one + + align:start position:0% +okay and that one + + + align:start position:0% +okay and that one +uh on the right is starting to look like + + align:start position:0% +uh on the right is starting to look like + + + align:start position:0% +uh on the right is starting to look like +another distribution you've probably + + align:start position:0% +another distribution you've probably + + + align:start position:0% +another distribution you've probably +seen before the normal distribution and + + align:start position:0% +seen before the normal distribution and + + + align:start position:0% +seen before the normal distribution and +uh we'll be encountering that uh soon + + align:start position:0% +uh we'll be encountering that uh soon + + + align:start position:0% +uh we'll be encountering that uh soon +enough and we'll also talk about the + + align:start position:0% +enough and we'll also talk about the + + + align:start position:0% +enough and we'll also talk about the +relationship between the binomial + + align:start position:0% +relationship between the binomial + + + align:start position:0% +relationship between the binomial +distribution and the normal + + align:start position:0% + + + + align:start position:0% + +distribution okay so let's step back and + + align:start position:0% +distribution okay so let's step back and + + + align:start position:0% +distribution okay so let's step back and +think a little bit more formally about + + align:start position:0% +think a little bit more formally about + + + align:start position:0% +think a little bit more formally about +this uh this notion of a probability + + align:start position:0% +this uh this notion of a probability + + + align:start position:0% +this uh this notion of a probability +function what is a probability function + + align:start position:0% +function what is a probability function + + + align:start position:0% +function what is a probability function +and you know sort of what properties + + align:start position:0% +and you know sort of what properties + + + align:start position:0% +and you know sort of what properties +does it have well the the probability + + align:start position:0% +does it have well the the probability + + + align:start position:0% +does it have well the the probability +function of X where X is a discrete + + align:start position:0% +function of X where X is a discrete + + + align:start position:0% +function of X where X is a discrete +random variable is defined as the + + align:start position:0% +random variable is defined as the + + + align:start position:0% +random variable is defined as the +function such that for any x f subx of + + align:start position:0% +function such that for any x f subx of + + + align:start position:0% +function such that for any x f subx of +little X is equal to the probability + + align:start position:0% +little X is equal to the probability + + + align:start position:0% +little X is equal to the probability +that X is equal to Little X okay so this + + align:start position:0% +that X is equal to Little X okay so this + + + align:start position:0% +that X is equal to Little X okay so this +is just this is just formalizing what we + + align:start position:0% +is just this is just formalizing what we + + + align:start position:0% +is just this is just formalizing what we +did in the last two examples we just + + align:start position:0% +did in the last two examples we just + + + align:start position:0% +did in the last two examples we just +created these functions we called them + + align:start position:0% +created these functions we called them + + + align:start position:0% +created these functions we called them +little F called them probability + + align:start position:0% +little F called them probability + + + align:start position:0% +little F called them probability +functions and denoted them little F I + + align:start position:0% +functions and denoted them little F I + + + align:start position:0% +functions and denoted them little F I +guess and all we did is we um just you + + align:start position:0% +guess and all we did is we um just you + + + align:start position:0% +guess and all we did is we um just you +know computed probabilities that our + + align:start position:0% +know computed probabilities that our + + + align:start position:0% +know computed probabilities that our +random variable was equal to various uh + + align:start position:0% +random variable was equal to various uh + + + align:start position:0% +random variable was equal to various uh +values and that defined our uh + + align:start position:0% +values and that defined our uh + + + align:start position:0% +values and that defined our uh +probability + + align:start position:0% +probability + + + align:start position:0% +probability +function okay so what are some of the + + align:start position:0% +function okay so what are some of the + + + align:start position:0% +function okay so what are some of the +properties that the probability function + + align:start position:0% +properties that the probability function + + + align:start position:0% +properties that the probability function +is going to have well because because + + align:start position:0% +is going to have well because because + + + align:start position:0% +is going to have well because because +it you know defines Pro the probability + + align:start position:0% +it you know defines Pro the probability + + + align:start position:0% +it you know defines Pro the probability +with which random variables take on + + align:start position:0% +with which random variables take on + + + align:start position:0% +with which random variables take on +various values it it is by its nature + + align:start position:0% +various values it it is by its nature + + + align:start position:0% +various values it it is by its nature +going to have certain properties that it + + align:start position:0% +going to have certain properties that it + + + align:start position:0% +going to have certain properties that it +always satisfies so in + + align:start position:0% +always satisfies so in + + + align:start position:0% +always satisfies so in +particular the value of the probability + + align:start position:0% +particular the value of the probability + + + align:start position:0% +particular the value of the probability +function for any X is going to be + + align:start position:0% +function for any X is going to be + + + align:start position:0% +function for any X is going to be +between zero and one okay and that's + + align:start position:0% +between zero and one okay and that's + + + align:start position:0% +between zero and one okay and that's +just because that's just by definition + + align:start position:0% +just because that's just by definition + + + align:start position:0% +just because that's just by definition +it's a probability okay and you can go + + align:start position:0% +it's a probability okay and you can go + + + align:start position:0% +it's a probability okay and you can go +back and you know we we can uh go back + + align:start position:0% +back and you know we we can uh go back + + + align:start position:0% +back and you know we we can uh go back +and check the examples I did all of the + + align:start position:0% +and check the examples I did all of the + + + align:start position:0% +and check the examples I did all of the +probabilities I computed were between + + align:start position:0% +probabilities I computed were between + + + align:start position:0% +probabilities I computed were between +zero and + + align:start position:0% +zero and + + + align:start position:0% +zero and +one the second um the uh second property + + align:start position:0% +one the second um the uh second property + + + align:start position:0% +one the second um the uh second property +is that if you sum up over all of the + + align:start position:0% +is that if you sum up over all of the + + + align:start position:0% +is that if you sum up over all of the +possible values that the random variable + + align:start position:0% +possible values that the random variable + + + align:start position:0% +possible values that the random variable +can take on then if you sum up the pro + + align:start position:0% +can take on then if you sum up the pro + + + align:start position:0% +can take on then if you sum up the pro +uh the probability function then that uh + + align:start position:0% +uh the probability function then that uh + + + align:start position:0% +uh the probability function then that uh +sum has to equal one okay again this + + align:start position:0% +sum has to equal one okay again this + + + align:start position:0% +sum has to equal one okay again this +follows directly from the fact that the + + align:start position:0% +follows directly from the fact that the + + + align:start position:0% +follows directly from the fact that the +probability function is uh you know sort + + align:start position:0% +probability function is uh you know sort + + + align:start position:0% +probability function is uh you know sort +of described probabilities so let me + + align:start position:0% +of described probabilities so let me + + + align:start position:0% +of described probabilities so let me +just go back and we can just sort of + + align:start position:0% +just go back and we can just sort of + + + align:start position:0% +just go back and we can just sort of +convince ourselves I did double check so + + align:start position:0% +convince ourselves I did double check so + + + align:start position:0% +convince ourselves I did double check so +it is in fact true but we can convince + + align:start position:0% +it is in fact true but we can convince + + + align:start position:0% +it is in fact true but we can convince +ourselves those things do sum to + + align:start position:0% +ourselves those things do sum to + + + align:start position:0% +ourselves those things do sum to +one and in the other + + align:start position:0% +one and in the other + + + align:start position:0% +one and in the other +example those also sum to one + + align:start position:0% + + + + align:start position:0% + +okay and um the third thing that uh very + + align:start position:0% +okay and um the third thing that uh very + + + align:start position:0% +okay and um the third thing that uh very +useful to know about a probability + + align:start position:0% +useful to know about a probability + + + align:start position:0% +useful to know about a probability +function is how to use it to compute + + align:start position:0% +function is how to use it to compute + + + align:start position:0% +function is how to use it to compute +probabilities okay so obviously if you + + align:start position:0% +probabilities okay so obviously if you + + + align:start position:0% +probabilities okay so obviously if you +just want the probability of a + + align:start position:0% +just want the probability of a + + + align:start position:0% +just want the probability of a +particular value of x you just the + + align:start position:0% +particular value of x you just the + + + align:start position:0% +particular value of x you just the +probability function gives it to you you + + align:start position:0% +probability function gives it to you you + + + align:start position:0% +probability function gives it to you you +just read it off but what if you want + + align:start position:0% +just read it off but what if you want + + + align:start position:0% +just read it off but what if you want +the probability of a whole set of + + align:start position:0% +the probability of a whole set of + + + align:start position:0% +the probability of a whole set of +different values of X well not + + align:start position:0% +different values of X well not + + + align:start position:0% +different values of X well not +surprisingly you just sum up the + + align:start position:0% +surprisingly you just sum up the + + + align:start position:0% +surprisingly you just sum up the +probability function over x's in that + + align:start position:0% +probability function over x's in that + + + align:start position:0% +probability function over x's in that +set okay and so that's going to uh + + align:start position:0% +set okay and so that's going to uh + + + align:start position:0% +set okay and so that's going to uh +that's going to be useful when we have + + align:start position:0% +that's going to be useful when we have + + + align:start position:0% +that's going to be useful when we have +when we're given a probability function + + align:start position:0% +when we're given a probability function + + + align:start position:0% +when we're given a probability function +for a random variable and we want to + + align:start position:0% +for a random variable and we want to + + + align:start position:0% +for a random variable and we want to +calculate the probability of a you know + + align:start position:0% +calculate the probability of a you know + + + align:start position:0% +calculate the probability of a you know +that X is in a particular set or region + + align:start position:0% +that X is in a particular set or region + + + align:start position:0% +that X is in a particular set or region +or something like + + align:start position:0% +or something like + + + align:start position:0% +or something like +that + + align:start position:0% + + + + align:start position:0% + +okay so I briefly mentioned continuous + + align:start position:0% +okay so I briefly mentioned continuous + + + align:start position:0% +okay so I briefly mentioned continuous +random variables a couple minutes ago so + + align:start position:0% +random variables a couple minutes ago so + + + align:start position:0% +random variables a couple minutes ago so +for continuous random variables we're + + align:start position:0% +for continuous random variables we're + + + align:start position:0% +for continuous random variables we're +rarely going to start with a verbal + + align:start position:0% +rarely going to start with a verbal + + + align:start position:0% +rarely going to start with a verbal +description of some kind of uh + + align:start position:0% +description of some kind of uh + + + align:start position:0% +description of some kind of uh +experiment like we with the discrete + + align:start position:0% +experiment like we with the discrete + + + align:start position:0% +experiment like we with the discrete +random variables um and instead we're + + align:start position:0% +random variables um and instead we're + + + align:start position:0% +random variables um and instead we're +typically just given a function that + + align:start position:0% +typically just given a function that + + + align:start position:0% +typically just given a function that +describes sort of the probabilities uh + + align:start position:0% +describes sort of the probabilities uh + + + align:start position:0% +describes sort of the probabilities uh +with which a r you know the + + align:start position:0% +with which a r you know the + + + align:start position:0% +with which a r you know the +probabilities with which uh continuous + + align:start position:0% +probabilities with which uh continuous + + + align:start position:0% +probabilities with which uh continuous +random variable is in various regions + + align:start position:0% +random variable is in various regions + + + align:start position:0% +random variable is in various regions +okay and that function is called a + + align:start position:0% +okay and that function is called a + + + align:start position:0% +okay and that function is called a +density um so all of you have seen lots + + align:start position:0% +density um so all of you have seen lots + + + align:start position:0% +density um so all of you have seen lots +of examples of densities the the over on + + align:start position:0% +of examples of densities the the over on + + + align:start position:0% +of examples of densities the the over on +the left is a normal density this is a a + + align:start position:0% +the left is a normal density this is a a + + + align:start position:0% +the left is a normal density this is a a +triangular density these are examples of + + align:start position:0% +triangular density these are examples of + + + align:start position:0% +triangular density these are examples of +log beta densities so we're you've all + + align:start position:0% +log beta densities so we're you've all + + + align:start position:0% +log beta densities so we're you've all +seen examples of them and we will sort + + align:start position:0% +seen examples of them and we will sort + + + align:start position:0% +seen examples of them and we will sort +of see many additional examples and sort + + align:start position:0% +of see many additional examples and sort + + + align:start position:0% +of see many additional examples and sort +of learn how to man manipulate them in + + align:start position:0% +of learn how to man manipulate them in + + + align:start position:0% +of learn how to man manipulate them in +various ways + + align:start position:0% +various ways + + + align:start position:0% +various ways +um but let me say a little bit more + + align:start position:0% +um but let me say a little bit more + + + align:start position:0% +um but let me say a little bit more +about this function the the density or + + align:start position:0% +about this function the the density or + + + align:start position:0% +about this function the the density or +also known as a probability density + + align:start position:0% +also known as a probability density + + + align:start position:0% +also known as a probability density +function okay so it's a a + + align:start position:0% +function okay so it's a a + + + align:start position:0% +function okay so it's a a +an analog in a lot of ways to the + + align:start position:0% +an analog in a lot of ways to the + + + align:start position:0% +an analog in a lot of ways to the +discrete probability function that we + + align:start position:0% +discrete probability function that we + + + align:start position:0% +discrete probability function that we +were just uh + + align:start position:0% +were just uh + + + align:start position:0% +were just uh +discussing and the next slide uh will + + align:start position:0% +discussing and the next slide uh will + + + align:start position:0% +discussing and the next slide uh will +talk about how they're similar and + + align:start position:0% +talk about how they're similar and + + + align:start position:0% +talk about how they're similar and +different uh but first let me give you + + align:start position:0% +different uh but first let me give you + + + align:start position:0% +different uh but first let me give you +sort of a more formal definition of what + + align:start position:0% +sort of a more formal definition of what + + + align:start position:0% +sort of a more formal definition of what +a a PDF or probability density function + + align:start position:0% +a a PDF or probability density function + + + align:start position:0% +a a PDF or probability density function +or density is okay well so in fact we + + align:start position:0% +or density is okay well so in fact we + + + align:start position:0% +or density is okay well so in fact we +Define The Continuous random variables + + align:start position:0% +Define The Continuous random variables + + + align:start position:0% +Define The Continuous random variables +in terms of this function so let me just + + align:start position:0% +in terms of this function so let me just + + + align:start position:0% +in terms of this function so let me just +uh do that that a random variable X is + + align:start position:0% +uh do that that a random variable X is + + + align:start position:0% +uh do that that a random variable X is +continuous if there exists a non- + + align:start position:0% +continuous if there exists a non- + + + align:start position:0% +continuous if there exists a non- +negative function f subx such that for + + align:start position:0% +negative function f subx such that for + + + align:start position:0% +negative function f subx such that for +any interval a uh in the real line the + + align:start position:0% +any interval a uh in the real line the + + + align:start position:0% +any interval a uh in the real line the +probability that X is an a is just equal + + align:start position:0% +probability that X is an a is just equal + + + align:start position:0% +probability that X is an a is just equal +to the integral over that region a of + + align:start position:0% +to the integral over that region a of + + + align:start position:0% +to the integral over that region a of +the the PDF F + + align:start position:0% + + + + align:start position:0% + +subx okay so note that I've given these + + align:start position:0% +subx okay so note that I've given these + + + align:start position:0% +subx okay so note that I've given these +two functions the the the one the the + + align:start position:0% +two functions the the the one the the + + + align:start position:0% +two functions the the the one the the +one that I said was analogous for the + + align:start position:0% +one that I said was analogous for the + + + align:start position:0% +one that I said was analogous for the +discrete random variable and the + + align:start position:0% +discrete random variable and the + + + align:start position:0% +discrete random variable and the +continuous random variable they have + + align:start position:0% +continuous random variable they have + + + align:start position:0% +continuous random variable they have +different terms one's called a + + align:start position:0% +different terms one's called a + + + align:start position:0% +different terms one's called a +probability function one's called a + + align:start position:0% +probability function one's called a + + + align:start position:0% +probability function one's called a +probability density function okay and we + + align:start position:0% +probability density function okay and we + + + align:start position:0% +probability density function okay and we +do that to emphasize the fact that + + align:start position:0% +do that to emphasize the fact that + + + align:start position:0% +do that to emphasize the fact that +they're not exactly the same they don't + + align:start position:0% +they're not exactly the same they don't + + + align:start position:0% +they're not exactly the same they don't +behave exactly the same way + + align:start position:0% +behave exactly the same way + + + align:start position:0% +behave exactly the same way +mathematically however they're going to + + align:start position:0% +mathematically however they're going to + + + align:start position:0% +mathematically however they're going to +be uh they're analogous in a lot of ways + + align:start position:0% +be uh they're analogous in a lot of ways + + + align:start position:0% +be uh they're analogous in a lot of ways +and they're going to be used in a lot of + + align:start position:0% +and they're going to be used in a lot of + + + align:start position:0% +and they're going to be used in a lot of +the same ways and so that's why we use + + align:start position:0% +the same ways and so that's why we use + + + align:start position:0% +the same ways and so that's why we use +the same notation uh this sort + + align:start position:0% + + + + align:start position:0% + +of f + + align:start position:0% +of f + + + align:start position:0% +of f +subx of little X notation okay so we use + + align:start position:0% +subx of little X notation okay so we use + + + align:start position:0% +subx of little X notation okay so we use +the same notation for both the sort of + + align:start position:0% +the same notation for both the sort of + + + align:start position:0% +the same notation for both the sort of +discrete probability function and the + + align:start position:0% +discrete probability function and the + + + align:start position:0% +discrete probability function and the +continuous probability density + + align:start position:0% +continuous probability density + + + align:start position:0% +continuous probability density +function + + align:start position:0% +function + + + align:start position:0% +function +okay + + align:start position:0% +okay + + + align:start position:0% +okay +oh and yes that's the PDF that the + + align:start position:0% + + + + align:start position:0% + +F okay so I said I was going to go + + align:start position:0% +F okay so I said I was going to go + + + align:start position:0% +F okay so I said I was going to go +through some of the similarities and the + + align:start position:0% +through some of the similarities and the + + + align:start position:0% +through some of the similarities and the +differences between a probability + + align:start position:0% +differences between a probability + + + align:start position:0% +differences between a probability +function and a probability density + + align:start position:0% +function and a probability density + + + align:start position:0% +function and a probability density +function so just like the probability + + align:start position:0% +function so just like the probability + + + align:start position:0% +function so just like the probability +function the probability density + + align:start position:0% +function the probability density + + + align:start position:0% +function the probability density +function has properties induced by our + + align:start position:0% +function has properties induced by our + + + align:start position:0% +function has properties induced by our +earlier definition of a probability okay + + align:start position:0% +earlier definition of a probability okay + + + align:start position:0% +earlier definition of a probability okay +so in particular it's always going to be + + align:start position:0% +so in particular it's always going to be + + + align:start position:0% +so in particular it's always going to be +non- + + align:start position:0% +non- + + + align:start position:0% +non- +negative now note that um it can be + + align:start position:0% +negative now note that um it can be + + + align:start position:0% +negative now note that um it can be +greater than one okay the probability + + align:start position:0% +greater than one okay the probability + + + align:start position:0% +greater than one okay the probability +function is never going to have a value + + align:start position:0% +function is never going to have a value + + + align:start position:0% +function is never going to have a value +greater than one because it is by + + align:start position:0% +greater than one because it is by + + + align:start position:0% +greater than one because it is by +definition a probability okay each point + + align:start position:0% +definition a probability okay each point + + + align:start position:0% +definition a probability okay each point +is just the probability that a random + + align:start position:0% +is just the probability that a random + + + align:start position:0% +is just the probability that a random +variable is equal to that point the + + align:start position:0% +variable is equal to that point the + + + align:start position:0% +variable is equal to that point the +definition of the probability density + + align:start position:0% +definition of the probability density + + + align:start position:0% +definition of the probability density +function is a little different okay so + + align:start position:0% +function is a little different okay so + + + align:start position:0% +function is a little different okay so +it can there can be regions or areas + + align:start position:0% +it can there can be regions or areas + + + align:start position:0% +it can there can be regions or areas +where the probability density function + + align:start position:0% +where the probability density function + + + align:start position:0% +where the probability density function +exceeds one that's perfectly + + align:start position:0% + + + + align:start position:0% + +fine okay um the probability + + align:start position:0% +fine okay um the probability + + + align:start position:0% +fine okay um the probability +function when you um sum up the the uh + + align:start position:0% +function when you um sum up the the uh + + + align:start position:0% +function when you um sum up the the uh +values for the probability function over + + align:start position:0% +values for the probability function over + + + align:start position:0% +values for the probability function over +all of the uh possible values of X you + + align:start position:0% +all of the uh possible values of X you + + + align:start position:0% +all of the uh possible values of X you +get one here the continuous analog is + + align:start position:0% +get one here the continuous analog is + + + align:start position:0% +get one here the continuous analog is +that we integrate over all the possible + + align:start position:0% +that we integrate over all the possible + + + align:start position:0% +that we integrate over all the possible +values of X and we get one + + align:start position:0% + + + + align:start position:0% + +okay and then again just like when we um + + align:start position:0% +okay and then again just like when we um + + + align:start position:0% +okay and then again just like when we um +when when I had the previous slide up + + align:start position:0% +when when I had the previous slide up + + + align:start position:0% +when when I had the previous slide up +with the uh probability function and I + + align:start position:0% +with the uh probability function and I + + + align:start position:0% +with the uh probability function and I +said if you want to compute the + + align:start position:0% +said if you want to compute the + + + align:start position:0% +said if you want to compute the +probability that X is in a particular + + align:start position:0% +probability that X is in a particular + + + align:start position:0% +probability that X is in a particular +region you just sum up the probability + + align:start position:0% +region you just sum up the probability + + + align:start position:0% +region you just sum up the probability +function over all of the X in that + + align:start position:0% +function over all of the X in that + + + align:start position:0% +function over all of the X in that +region well here you do the continuous + + align:start position:0% +region well here you do the continuous + + + align:start position:0% +region well here you do the continuous +analog which is you integrate over that + + align:start position:0% +analog which is you integrate over that + + + align:start position:0% +analog which is you integrate over that +region okay so we're interested in X um + + align:start position:0% +region okay so we're interested in X um + + + align:start position:0% +region okay so we're interested in X um +the probability that X is between A and + + align:start position:0% +the probability that X is between A and + + + align:start position:0% +the probability that X is between A and +B oh actually oh no I guess I have it + + align:start position:0% +B oh actually oh no I guess I have it + + + align:start position:0% +B oh actually oh no I guess I have it +over here so the probability of that X + + align:start position:0% +over here so the probability of that X + + + align:start position:0% +over here so the probability of that X +is in some region capital A which we + + align:start position:0% +is in some region capital A which we + + + align:start position:0% +is in some region capital A which we +Define as an interval uh between A and B + + align:start position:0% +Define as an interval uh between A and B + + + align:start position:0% +Define as an interval uh between A and B +uh all we do is we just integrate over + + align:start position:0% +uh all we do is we just integrate over + + + align:start position:0% +uh all we do is we just integrate over +that region a okay + + align:start position:0% + + + + align:start position:0% + +um a couple things to keep in mind about + + align:start position:0% +um a couple things to keep in mind about + + + align:start position:0% +um a couple things to keep in mind about +a probability density function uh you + + align:start position:0% +a probability density function uh you + + + align:start position:0% +a probability density function uh you +know sort of um relative to the + + align:start position:0% +know sort of um relative to the + + + align:start position:0% +know sort of um relative to the +probability function so the value of a + + align:start position:0% +probability function so the value of a + + + align:start position:0% +probability function so the value of a +probability density function at a + + align:start position:0% +probability density function at a + + + align:start position:0% +probability density function at a +particular X does not have the same + + align:start position:0% +particular X does not have the same + + + align:start position:0% +particular X does not have the same +interpretation as a probability okay in + + align:start position:0% +interpretation as a probability okay in + + + align:start position:0% +interpretation as a probability okay in +fact the probability that the random + + align:start position:0% +fact the probability that the random + + + align:start position:0% +fact the probability that the random +variable X is equal to some number + + align:start position:0% +variable X is equal to some number + + + align:start position:0% +variable X is equal to some number +Little X is equal to zero for any X if x + + align:start position:0% +Little X is equal to zero for any X if x + + + align:start position:0% +Little X is equal to zero for any X if x +if big X is a continuous random + + align:start position:0% +if big X is a continuous random + + + align:start position:0% +if big X is a continuous random +variable okay so this is the this is the + + align:start position:0% +variable okay so this is the this is the + + + align:start position:0% +variable okay so this is the this is the +sort of fundamental difference between a + + align:start position:0% +sort of fundamental difference between a + + + align:start position:0% +sort of fundamental difference between a +discrete random variable and a + + align:start position:0% +discrete random variable and a + + + align:start position:0% +discrete random variable and a +continuous random variable discrete + + align:start position:0% +continuous random variable discrete + + + align:start position:0% +continuous random variable discrete +random variable takes on particular + + align:start position:0% +random variable takes on particular + + + align:start position:0% +random variable takes on particular +values with positive probability an a a + + align:start position:0% +values with positive probability an a a + + + align:start position:0% +values with positive probability an a a +finite or countably infinite number of + + align:start position:0% +finite or countably infinite number of + + + align:start position:0% +finite or countably infinite number of +particular values with positive + + align:start position:0% +particular values with positive + + + align:start position:0% +particular values with positive +probability uh the a continuous random + + align:start position:0% +probability uh the a continuous random + + + align:start position:0% +probability uh the a continuous random +variable is equal to a particular value + + align:start position:0% +variable is equal to a particular value + + + align:start position:0% +variable is equal to a particular value +with probability zero but instead we + + align:start position:0% +with probability zero but instead we + + + align:start position:0% +with probability zero but instead we +talk about it being in a region for + + align:start position:0% +talk about it being in a region for + + + align:start position:0% +talk about it being in a region for +instance with positive + + align:start position:0% +instance with positive + + + align:start position:0% +instance with positive +probability okay yes I have a question + + align:start position:0% +probability okay yes I have a question + + + align:start position:0% +probability okay yes I have a question +where so if we have value of f subx of + + align:start position:0% +where so if we have value of f subx of + + + align:start position:0% +where so if we have value of f subx of +little X is greater than one then how do + + align:start position:0% +little X is greater than one then how do + + + align:start position:0% +little X is greater than one then how do +you integrate everything up to well + + align:start position:0% +you integrate everything up to well + + + align:start position:0% +you integrate everything up to well +because it can it can be greater than + + align:start position:0% +because it can it can be greater than + + + align:start position:0% +because it can it can be greater than +one on an interval that's that's uh uh + + align:start position:0% +one on an interval that's that's uh uh + + + align:start position:0% +one on an interval that's that's uh uh +shorter than one so like for instance + + align:start position:0% +shorter than one so like for instance + + + align:start position:0% +shorter than one so like for instance +let me draw an + + align:start position:0% +let me draw an + + + align:start position:0% +let me draw an +example + + align:start position:0% +example + + + align:start position:0% +example +so let's take the unit interval and we + + align:start position:0% +so let's take the unit interval and we + + + align:start position:0% +so let's take the unit interval and we +have a density that's defined on the + + align:start position:0% +have a density that's defined on the + + + align:start position:0% +have a density that's defined on the +unit interval well what uh on the unit + + align:start position:0% +unit interval well what uh on the unit + + + align:start position:0% +unit interval well what uh on the unit +interval can integrate to one well we + + align:start position:0% +interval can integrate to one well we + + + align:start position:0% +interval can integrate to one well we +know if we + + align:start position:0% +know if we + + + align:start position:0% +know if we +just let's + + align:start position:0% +just let's + + + align:start position:0% +just let's +consider this function right that + + align:start position:0% +consider this function right that + + + align:start position:0% +consider this function right that +integrates to one it never exceeds one + + align:start position:0% + + + + align:start position:0% + +but let's see if I can draw this in a + + align:start position:0% +but let's see if I can draw this in a + + + align:start position:0% +but let's see if I can draw this in a +reasonable way + + align:start position:0% +reasonable way + + + align:start position:0% +reasonable way +this function should also integrate to + + align:start position:0% +this function should also integrate to + + + align:start position:0% +this function should also integrate to +one over the unit interval but it does + + align:start position:0% +one over the unit interval but it does + + + align:start position:0% +one over the unit interval but it does +exceed one for part of the time + + align:start position:0% + + + + align:start position:0% + +okay okay was there anything else I + + align:start position:0% +okay okay was there anything else I + + + align:start position:0% +okay okay was there anything else I +wanted to say about this any other + + align:start position:0% + + + + align:start position:0% + +questions no + + align:start position:0% +questions no + + + align:start position:0% +questions no +okay okay so I I do want to pause for a + + align:start position:0% +okay okay so I I do want to pause for a + + + align:start position:0% +okay okay so I I do want to pause for a +second to to um give to say a word about + + align:start position:0% +second to to um give to say a word about + + + align:start position:0% +second to to um give to say a word about +terminology and notation so I sort of + + align:start position:0% +terminology and notation so I sort of + + + align:start position:0% +terminology and notation so I sort of +did a little bit of a search on the + + align:start position:0% +did a little bit of a search on the + + + align:start position:0% +did a little bit of a search on the +internet and tried to find what the + + align:start position:0% +internet and tried to find what the + + + align:start position:0% +internet and tried to find what the +standard terminology and standard + + align:start position:0% +standard terminology and standard + + + align:start position:0% +standard terminology and standard +notation for all of these entities in + + align:start position:0% +notation for all of these entities in + + + align:start position:0% +notation for all of these entities in +probability is and it turns out there + + align:start position:0% +probability is and it turns out there + + + align:start position:0% +probability is and it turns out there +isn't one there is a huge range of + + align:start position:0% +isn't one there is a huge range of + + + align:start position:0% +isn't one there is a huge range of +different terms that different textbooks + + align:start position:0% +different terms that different textbooks + + + align:start position:0% +different terms that different textbooks +use and different websites use and and + + align:start position:0% +use and different websites use and and + + + align:start position:0% +use and different websites use and and +uh you know both formal terms and + + align:start position:0% +uh you know both formal terms and + + + align:start position:0% +uh you know both formal terms and +informal terms so I just want you to be + + align:start position:0% +informal terms so I just want you to be + + + align:start position:0% +informal terms so I just want you to be +aware of that if you're looking if + + align:start position:0% +aware of that if you're looking if + + + align:start position:0% +aware of that if you're looking if +you're using a a book on probability as + + align:start position:0% +you're using a a book on probability as + + + align:start position:0% +you're using a a book on probability as +a resource uh looking things up the + + align:start position:0% +a resource uh looking things up the + + + align:start position:0% +a resource uh looking things up the +terminology um might be different than + + align:start position:0% +terminology um might be different than + + + align:start position:0% +terminology um might be different than +what we're using in class um I'm going + + align:start position:0% +what we're using in class um I'm going + + + align:start position:0% +what we're using in class um I'm going +to try to be consistent internally + + align:start position:0% +to try to be consistent internally + + + align:start position:0% +to try to be consistent internally +consistent but that doesn't mean that I + + align:start position:0% +consistent but that doesn't mean that I + + + align:start position:0% +consistent but that doesn't mean that I +will always be completely formal so for + + align:start position:0% +will always be completely formal so for + + + align:start position:0% +will always be completely formal so for +instance I will try to say probability + + align:start position:0% +instance I will try to say probability + + + align:start position:0% +instance I will try to say probability +function when I'm referring to or sorry + + align:start position:0% +function when I'm referring to or sorry + + + align:start position:0% +function when I'm referring to or sorry +yeah probability function when I'm + + align:start position:0% +yeah probability function when I'm + + + align:start position:0% +yeah probability function when I'm +referring to uh a discrete random + + align:start position:0% +referring to uh a discrete random + + + align:start position:0% +referring to uh a discrete random +variable and I'll try to say probability + + align:start position:0% +variable and I'll try to say probability + + + align:start position:0% +variable and I'll try to say probability +density function when I'm referring to a + + align:start position:0% +density function when I'm referring to a + + + align:start position:0% +density function when I'm referring to a +continuous random variable but sometimes + + align:start position:0% +continuous random variable but sometimes + + + align:start position:0% +continuous random variable but sometimes +I'll just Punt and say + + align:start position:0% +I'll just Punt and say + + + align:start position:0% +I'll just Punt and say +distribution and that's kind of an + + align:start position:0% +distribution and that's kind of an + + + align:start position:0% +distribution and that's kind of an +informal catchall phrase + + align:start position:0% + + + + align:start position:0% + +okay but do do uh feel free to ask if + + align:start position:0% +okay but do do uh feel free to ask if + + + align:start position:0% +okay but do do uh feel free to ask if +you have uh you know clar if you want + + align:start position:0% +you have uh you know clar if you want + + + align:start position:0% +you have uh you know clar if you want +clarification on these + + align:start position:0% +clarification on these + + + align:start position:0% +clarification on these +points okay yep question you how + + align:start position:0% +points okay yep question you how + + + align:start position:0% +points okay yep question you how +continuous distribution at Point the + + align:start position:0% +continuous distribution at Point the + + + align:start position:0% +continuous distribution at Point the +probably zero so let's say you have a + + align:start position:0% +probably zero so let's say you have a + + + align:start position:0% +probably zero so let's say you have a +spike at that one point maybe goes to + + align:start position:0% +spike at that one point maybe goes to + + + align:start position:0% +spike at that one point maybe goes to +Infinity so you that from distribution + + align:start position:0% +Infinity so you that from distribution + + + align:start position:0% +Infinity so you that from distribution +but had this integration fail or what + + align:start position:0% +but had this integration fail or what + + + align:start position:0% +but had this integration fail or what +problem that yeah I mean it's just it's + + align:start position:0% +problem that yeah I mean it's just it's + + + align:start position:0% +problem that yeah I mean it's just it's +just not sort of a well- behaved um + + align:start position:0% +just not sort of a well- behaved um + + + align:start position:0% +just not sort of a well- behaved um +distribution and so yeah so basically + + align:start position:0% +distribution and so yeah so basically + + + align:start position:0% +distribution and so yeah so basically +you know things like um you know + + align:start position:0% +you know things like um you know + + + align:start position:0% +you know things like um you know +regularity conditions that ensure that + + align:start position:0% +regularity conditions that ensure that + + + align:start position:0% +regularity conditions that ensure that +it's integrable might not uh still exist + + align:start position:0% +it's integrable might not uh still exist + + + align:start position:0% +it's integrable might not uh still exist +so what you're thinking of is like a + + align:start position:0% +so what you're thinking of is like a + + + align:start position:0% +so what you're thinking of is like a +distribution like this that's sort of + + align:start position:0% +distribution like this that's sort of + + + align:start position:0% +distribution like this that's sort of +getting that's kind of uh in the limit + + align:start position:0% +getting that's kind of uh in the limit + + + align:start position:0% +getting that's kind of uh in the limit +going down to a single point getting + + align:start position:0% +going down to a single point getting + + + align:start position:0% +going down to a single point getting +getting more concentrated more + + align:start position:0% +getting more concentrated more + + + align:start position:0% +getting more concentrated more +concentrated like one Break um so you + + align:start position:0% +concentrated like one Break um so you + + + align:start position:0% +concentrated like one Break um so you +have at one point just a + + align:start position:0% +have at one point just a + + + align:start position:0% +have at one point just a +spike so what you're what you're + + align:start position:0% +spike so what you're what you're + + + align:start position:0% +spike so what you're what you're +actually perhaps talking about is a + + align:start position:0% +actually perhaps talking about is a + + + align:start position:0% +actually perhaps talking about is a +mixed distribution so such a so I + + align:start position:0% +mixed distribution so such a so I + + + align:start position:0% +mixed distribution so such a so I +haven't mentioned them but such a thing + + align:start position:0% +haven't mentioned them but such a thing + + + align:start position:0% +haven't mentioned them but such a thing +definitely exists so um tell me if this + + align:start position:0% +definitely exists so um tell me if this + + + align:start position:0% +definitely exists so um tell me if this +is what you mean so you + + align:start position:0% +is what you mean so you + + + align:start position:0% +is what you mean so you +have a distribution for a continuous + + align:start position:0% +have a distribution for a continuous + + + align:start position:0% +have a distribution for a continuous +random + + align:start position:0% + + + + align:start position:0% + +variable and then maybe at this one + + align:start position:0% +variable and then maybe at this one + + + align:start position:0% +variable and then maybe at this one +particular well actually let me do a + + align:start position:0% +particular well actually let me do a + + + align:start position:0% +particular well actually let me do a +sort of a example that makes more + + align:start position:0% + + + + align:start position:0% + +sense and maybe so maybe this is the + + align:start position:0% +sense and maybe so maybe this is the + + + align:start position:0% +sense and maybe so maybe this is the +distribution of some + + align:start position:0% +distribution of some + + + align:start position:0% +distribution of some +measurement and then our how our + + align:start position:0% +measurement and then our how our + + + align:start position:0% +measurement and then our how our +measuring technology uh can't measure + + align:start position:0% +measuring technology uh can't measure + + + align:start position:0% +measuring technology uh can't measure +anything above this point so everything + + align:start position:0% +anything above this point so everything + + + align:start position:0% +anything above this point so everything +every measurement that we would like to + + align:start position:0% +every measurement that we would like to + + + align:start position:0% +every measurement that we would like to +take at this you know above this point + + align:start position:0% +take at this you know above this point + + + align:start position:0% +take at this you know above this point +gets recorded at this point is that what + + align:start position:0% +gets recorded at this point is that what + + + align:start position:0% +gets recorded at this point is that what +you mean so there is there is a point + + align:start position:0% +you mean so there is there is a point + + + align:start position:0% +you mean so there is there is a point +Mass here this is like we have a + + align:start position:0% +Mass here this is like we have a + + + align:start position:0% +Mass here this is like we have a +continuous part of the random variable + + align:start position:0% +continuous part of the random variable + + + align:start position:0% +continuous part of the random variable +and then this one part of the random + + align:start position:0% +and then this one part of the random + + + align:start position:0% +and then this one part of the random +variable is + + align:start position:0% +variable is + + + align:start position:0% +variable is +discreet and so there is you know sort + + align:start position:0% +discreet and so there is you know sort + + + align:start position:0% +discreet and so there is you know sort +of positive probability at that + + align:start position:0% +of positive probability at that + + + align:start position:0% +of positive probability at that +point so yeah you're absolutely right + + align:start position:0% +point so yeah you're absolutely right + + + align:start position:0% +point so yeah you're absolutely right +it's just called a mixed random variable + + align:start position:0% +it's just called a mixed random variable + + + align:start position:0% +it's just called a mixed random variable +and when we we deal with mixed random + + align:start position:0% +and when we we deal with mixed random + + + align:start position:0% +and when we we deal with mixed random +variables we just have to be cognizant + + align:start position:0% +variables we just have to be cognizant + + + align:start position:0% +variables we just have to be cognizant +of the fact that none of these there's + + align:start position:0% +of the fact that none of these there's + + + align:start position:0% +of the fact that none of these there's +there isn't a positive probability on + + align:start position:0% +there isn't a positive probability on + + + align:start position:0% +there isn't a positive probability on +any of these points but on this one + + align:start position:0% +any of these points but on this one + + + align:start position:0% +any of these points but on this one +particular point there is a point Mass + + align:start position:0% +particular point there is a point Mass + + + align:start position:0% +particular point there is a point Mass +we have to treat that + + align:start position:0% + + + + align:start position:0% + +differently + + align:start position:0% +differently + + + align:start position:0% +differently +yeah okay other questions + + align:start position:0% +yeah okay other questions + + + align:start position:0% +yeah okay other questions +nope okay so let me go through an + + align:start position:0% +nope okay so let me go through an + + + align:start position:0% +nope okay so let me go through an +example so let A and B be real numbers + + align:start position:0% +example so let A and B be real numbers + + + align:start position:0% +example so let A and B be real numbers +uh such that uh a is less than b okay so + + align:start position:0% +uh such that uh a is less than b okay so + + + align:start position:0% +uh such that uh a is less than b okay so +a defines an interval on the real + + align:start position:0% +a defines an interval on the real + + + align:start position:0% +a defines an interval on the real +line and suppose that we have a random + + align:start position:0% +line and suppose that we have a random + + + align:start position:0% +line and suppose that we have a random +variable X and it's defined in such a + + align:start position:0% +variable X and it's defined in such a + + + align:start position:0% +variable X and it's defined in such a +way that the probability of X belonging + + align:start position:0% +way that the probability of X belonging + + + align:start position:0% +way that the probability of X belonging +to any sub interval of s is proportional + + align:start position:0% +to any sub interval of s is proportional + + + align:start position:0% +to any sub interval of s is proportional +to the length of the sub interval + + align:start position:0% +to the length of the sub interval + + + align:start position:0% +to the length of the sub interval +okay so then and you can uh perhaps this + + align:start position:0% +okay so then and you can uh perhaps this + + + align:start position:0% +okay so then and you can uh perhaps this +isn't a formal proof but you might be + + align:start position:0% +isn't a formal proof but you might be + + + align:start position:0% +isn't a formal proof but you might be +able to convince yourself if you think + + align:start position:0% +able to convince yourself if you think + + + align:start position:0% +able to convince yourself if you think +about it the uh the probability density + + align:start position:0% +about it the uh the probability density + + + align:start position:0% +about it the uh the probability density +function of that random variable that + + align:start position:0% +function of that random variable that + + + align:start position:0% +function of that random variable that +I've just described uh will take this + + align:start position:0% +I've just described uh will take this + + + align:start position:0% +I've just described uh will take this +form okay so basically it's going to + + align:start position:0% +form okay so basically it's going to + + + align:start position:0% +form okay so basically it's going to +have + + align:start position:0% + + + + align:start position:0% + +it's going to have a uniform + + align:start position:0% +it's going to have a uniform + + + align:start position:0% +it's going to have a uniform +density at Value 1 over B minus + + align:start position:0% + + + + align:start position:0% + +a uh over the interval A to B and it's + + align:start position:0% +a uh over the interval A to B and it's + + + align:start position:0% +a uh over the interval A to B and it's +going to be zero otherwise okay + + align:start position:0% +going to be zero otherwise okay + + + align:start position:0% +going to be zero otherwise okay +so definitely + + align:start position:0% +so definitely + + + align:start position:0% +so definitely +once you write down this uh PDF and you + + align:start position:0% +once you write down this uh PDF and you + + + align:start position:0% +once you write down this uh PDF and you +think about uh this description of the + + align:start position:0% +think about uh this description of the + + + align:start position:0% +think about uh this description of the +random variable you certainly can + + align:start position:0% +random variable you certainly can + + + align:start position:0% +random variable you certainly can +convince yourself I think that um you + + align:start position:0% +convince yourself I think that um you + + + align:start position:0% +convince yourself I think that um you +know any the the the FRA the probability + + align:start position:0% +know any the the the FRA the probability + + + align:start position:0% +know any the the the FRA the probability +that the random variable X is in any sub + + align:start position:0% +that the random variable X is in any sub + + + align:start position:0% +that the random variable X is in any sub +interval of a is going to be + + align:start position:0% +interval of a is going to be + + + align:start position:0% +interval of a is going to be +proportional to the length of that sub + + align:start position:0% +proportional to the length of that sub + + + align:start position:0% +proportional to the length of that sub +interval because this is just a constant + + align:start position:0% +interval because this is just a constant + + + align:start position:0% +interval because this is just a constant +prob ability or yeah constant PDF over + + align:start position:0% +prob ability or yeah constant PDF over + + + align:start position:0% +prob ability or yeah constant PDF over +that interval + + align:start position:0% +that interval + + + align:start position:0% +that interval +okay so this is a special random + + align:start position:0% +okay so this is a special random + + + align:start position:0% +okay so this is a special random +variable we'll see this um again over + + align:start position:0% +variable we'll see this um again over + + + align:start position:0% +variable we'll see this um again over +the course of the semester it is perhaps + + align:start position:0% +the course of the semester it is perhaps + + + align:start position:0% +the course of the semester it is perhaps +my favorite random variable it is the + + align:start position:0% +my favorite random variable it is the + + + align:start position:0% +my favorite random variable it is the +uniform random variable and um it's it + + align:start position:0% +uniform random variable and um it's it + + + align:start position:0% +uniform random variable and um it's it +comes in handy in lots of different uh + + align:start position:0% +comes in handy in lots of different uh + + + align:start position:0% +comes in handy in lots of different uh +circumstances um and oh I think actually + + align:start position:0% +circumstances um and oh I think actually + + + align:start position:0% +circumstances um and oh I think actually +I drew a picture up here on the board + + align:start position:0% +I drew a picture up here on the board + + + align:start position:0% +I drew a picture up here on the board +but I think I made have a picture in my + + align:start position:0% +but I think I made have a picture in my + + + align:start position:0% +but I think I made have a picture in my +next slide yep there's a picture + + align:start position:0% + + + + align:start position:0% + +okay so um if you want to compute the + + align:start position:0% +okay so um if you want to compute the + + + align:start position:0% +okay so um if you want to compute the +probability of a uniform AB random + + align:start position:0% +probability of a uniform AB random + + + align:start position:0% +probability of a uniform AB random +variable being in some interval CD which + + align:start position:0% +variable being in some interval CD which + + + align:start position:0% +variable being in some interval CD which +is a sub interval of ab uh well we know + + align:start position:0% +is a sub interval of ab uh well we know + + + align:start position:0% +is a sub interval of ab uh well we know +one way that we can you can do that + + align:start position:0% +one way that we can you can do that + + + align:start position:0% +one way that we can you can do that +because we saw that um uh several slides + + align:start position:0% +because we saw that um uh several slides + + + align:start position:0% +because we saw that um uh several slides +ago you can just + + align:start position:0% +ago you can just + + + align:start position:0% +ago you can just +integrate the value + + align:start position:0% +integrate the value + + + align:start position:0% +integrate the value +of the probability density function over + + align:start position:0% +of the probability density function over + + + align:start position:0% +of the probability density function over +that sub interval okay but in fact + + align:start position:0% +that sub interval okay but in fact + + + align:start position:0% +that sub interval okay but in fact +there's kind of an easier way to do it + + align:start position:0% +there's kind of an easier way to do it + + + align:start position:0% +there's kind of an easier way to do it +with a uniform uh distribution a uniform + + align:start position:0% +with a uniform uh distribution a uniform + + + align:start position:0% +with a uniform uh distribution a uniform +random variable we don't have to + + align:start position:0% +random variable we don't have to + + + align:start position:0% +random variable we don't have to +actually do the integration uh because + + align:start position:0% +actually do the integration uh because + + + align:start position:0% +actually do the integration uh because +this is just constant over the whole + + align:start position:0% +this is just constant over the whole + + + align:start position:0% +this is just constant over the whole +interval so to compute the probability + + align:start position:0% +interval so to compute the probability + + + align:start position:0% +interval so to compute the probability +of any sub interval uh you know as I + + align:start position:0% +of any sub interval uh you know as I + + + align:start position:0% +of any sub interval uh you know as I +said it's just a the length of the sub + + align:start position:0% +said it's just a the length of the sub + + + align:start position:0% +said it's just a the length of the sub +interval over uh the length of the the + + align:start position:0% +interval over uh the length of the the + + + align:start position:0% +interval over uh the length of the the +entire support of the random + + align:start position:0% +entire support of the random + + + align:start position:0% +entire support of the random +variable so we've got probability + + align:start position:0% +variable so we've got probability + + + align:start position:0% +variable so we've got probability +functions and we've got probability + + align:start position:0% +functions and we've got probability + + + align:start position:0% +functions and we've got probability +density functions and for two different + + align:start position:0% +density functions and for two different + + + align:start position:0% +density functions and for two different +kinds of random variables those describe + + align:start position:0% +kinds of random variables those describe + + + align:start position:0% +kinds of random variables those describe +the um the sort of uh probabilities that + + align:start position:0% +the um the sort of uh probabilities that + + + align:start position:0% +the um the sort of uh probabilities that +the random variables are in different + + align:start position:0% +the random variables are in different + + + align:start position:0% +the random variables are in different +regions or take on different values + + align:start position:0% +regions or take on different values + + + align:start position:0% +regions or take on different values +there it's a complete description okay + + align:start position:0% +there it's a complete description okay + + + align:start position:0% +there it's a complete description okay +but sometimes it's going to be handy to + + align:start position:0% +but sometimes it's going to be handy to + + + align:start position:0% +but sometimes it's going to be handy to +express those probabilities related to a + + align:start position:0% +express those probabilities related to a + + + align:start position:0% +express those probabilities related to a +random variable in an alternative form + + align:start position:0% +random variable in an alternative form + + + align:start position:0% +random variable in an alternative form +okay doubly handy is the fact that this + + align:start position:0% +okay doubly handy is the fact that this + + + align:start position:0% +okay doubly handy is the fact that this +alternative form has the same definition + + align:start position:0% +alternative form has the same definition + + + align:start position:0% +alternative form has the same definition +regardless of whether the random + + align:start position:0% +regardless of whether the random + + + align:start position:0% +regardless of whether the random +variable is discret or + + align:start position:0% +variable is discret or + + + align:start position:0% +variable is discret or +continuous okay and this alternative + + align:start position:0% +continuous okay and this alternative + + + align:start position:0% +continuous okay and this alternative +form is the cumulative distribution + + align:start position:0% +form is the cumulative distribution + + + align:start position:0% +form is the cumulative distribution +function so a cumulative distribution + + align:start position:0% +function so a cumulative distribution + + + align:start position:0% +function so a cumulative distribution +function uh which will often abbreviate + + align:start position:0% +function uh which will often abbreviate + + + align:start position:0% +function uh which will often abbreviate +as CDF um it's denoted with a cap + + align:start position:0% +as CDF um it's denoted with a cap + + + align:start position:0% +as CDF um it's denoted with a cap +capital F + + align:start position:0% +capital F + + + align:start position:0% +capital F +subx and um it is defined simply as the + + align:start position:0% +subx and um it is defined simply as the + + + align:start position:0% +subx and um it is defined simply as the +probability that the random variable X + + align:start position:0% +probability that the random variable X + + + align:start position:0% +probability that the random variable X +is less than or equal to some value + + align:start position:0% +is less than or equal to some value + + + align:start position:0% +is less than or equal to some value +Little X okay same definition for both + + align:start position:0% +Little X okay same definition for both + + + align:start position:0% +Little X okay same definition for both +the um uh discrete and continuous random + + align:start position:0% + + + + align:start position:0% + +variables and I should say by the way + + align:start position:0% +variables and I should say by the way + + + align:start position:0% +variables and I should say by the way +sometimes I often like to put uh the + + align:start position:0% +sometimes I often like to put uh the + + + align:start position:0% +sometimes I often like to put uh the +random variable as a subscript on either + + align:start position:0% +random variable as a subscript on either + + + align:start position:0% +random variable as a subscript on either +the probability function or the PDF or + + align:start position:0% +the probability function or the PDF or + + + align:start position:0% +the probability function or the PDF or +the CDF just so we you know just to keep + + align:start position:0% +the CDF just so we you know just to keep + + + align:start position:0% +the CDF just so we you know just to keep +things straight um it doesn't have to be + + align:start position:0% +things straight um it doesn't have to be + + + align:start position:0% +things straight um it doesn't have to be +there so sometimes I'll omit there's no + + align:start position:0% +there so sometimes I'll omit there's no + + + align:start position:0% +there so sometimes I'll omit there's no +chance of um ambiguity sometimes I'll + + align:start position:0% +chance of um ambiguity sometimes I'll + + + align:start position:0% +chance of um ambiguity sometimes I'll +omit the subscript and just use the + + align:start position:0% +omit the subscript and just use the + + + align:start position:0% +omit the subscript and just use the +little f for probability function or PDF + + align:start position:0% +little f for probability function or PDF + + + align:start position:0% +little f for probability function or PDF +and then the capital F for uh + + align:start position:0% +and then the capital F for uh + + + align:start position:0% +and then the capital F for uh +CDF + + align:start position:0% + + + + align:start position:0% + +okay okay so just like in the case of + + align:start position:0% +okay okay so just like in the case of + + + align:start position:0% +okay okay so just like in the case of +the probability function and the + + align:start position:0% +the probability function and the + + + align:start position:0% +the probability function and the +probability density function the + + align:start position:0% +probability density function the + + + align:start position:0% +probability density function the +properties of probability are going to + + align:start position:0% +properties of probability are going to + + + align:start position:0% +properties of probability are going to +imply certain things about cdfs there's + + align:start position:0% +imply certain things about cdfs there's + + + align:start position:0% +imply certain things about cdfs there's +certain ways that cdfs are going to + + align:start position:0% +certain ways that cdfs are going to + + + align:start position:0% +certain ways that cdfs are going to +behave so uh first of all the CDF is + + align:start position:0% +behave so uh first of all the CDF is + + + align:start position:0% +behave so uh first of all the CDF is +always going to have values between zero + + align:start position:0% +always going to have values between zero + + + align:start position:0% +always going to have values between zero +and one okay and again I mean just you + + align:start position:0% +and one okay and again I mean just you + + + align:start position:0% +and one okay and again I mean just you +can look back at the definition and + + align:start position:0% +can look back at the definition and + + + align:start position:0% +can look back at the definition and +convince yourself that this is + + align:start position:0% +convince yourself that this is + + + align:start position:0% +convince yourself that this is +true uh second thing is that the CDF is + + align:start position:0% +true uh second thing is that the CDF is + + + align:start position:0% +true uh second thing is that the CDF is +always going to be non decreasing in + + align:start position:0% +always going to be non decreasing in + + + align:start position:0% +always going to be non decreasing in +X okay and again if you think about the + + align:start position:0% +X okay and again if you think about the + + + align:start position:0% +X okay and again if you think about the +definition it's just the definition that + + align:start position:0% +definition it's just the definition that + + + align:start position:0% +definition it's just the definition that +X the random variable X is less than or + + align:start position:0% +X the random variable X is less than or + + + align:start position:0% +X the random variable X is less than or +equal to Little X as little X increases + + align:start position:0% +equal to Little X as little X increases + + + align:start position:0% +equal to Little X as little X increases +uh then um you know capital F is not + + align:start position:0% +uh then um you know capital F is not + + + align:start position:0% +uh then um you know capital F is not +ever going to + + align:start position:0% + + + + align:start position:0% + +decrease uh the um third property is + + align:start position:0% +decrease uh the um third property is + + + align:start position:0% +decrease uh the um third property is +that the limit as X goes to negative + + align:start position:0% +that the limit as X goes to negative + + + align:start position:0% +that the limit as X goes to negative +Infinity um of the CDF is equal to + + align:start position:0% + + + + align:start position:0% + +zero and um along with that is the limit + + align:start position:0% +zero and um along with that is the limit + + + align:start position:0% +zero and um along with that is the limit +as X goes to positive Infinity of the + + align:start position:0% +as X goes to positive Infinity of the + + + align:start position:0% +as X goes to positive Infinity of the +CDF is equal to one okay so what are + + align:start position:0% +CDF is equal to one okay so what are + + + align:start position:0% +CDF is equal to one okay so what are +these cdfs going to look + + align:start position:0% + + + + align:start position:0% + +like so we know that they're always + + align:start position:0% +like so we know that they're always + + + align:start position:0% +like so we know that they're always +going to start at zero okay so the these + + align:start position:0% +going to start at zero okay so the these + + + align:start position:0% +going to start at zero okay so the these +are just uh you know sort of values that + + align:start position:0% +are just uh you know sort of values that + + + align:start position:0% +are just uh you know sort of values that +X can take on so the CDF is always going + + align:start position:0% +X can take on so the CDF is always going + + + align:start position:0% +X can take on so the CDF is always going +to start at zero it's going to go up + + align:start position:0% +to start at zero it's going to go up + + + align:start position:0% +to start at zero it's going to go up +it's never going to decrease it might + + align:start position:0% +it's never going to decrease it might + + + align:start position:0% +it's never going to decrease it might +have flat + + align:start position:0% + + + + align:start position:0% + +Parts relatively more flat parts and + + align:start position:0% + + + + align:start position:0% + +then in the limit as X goes to Infinity + + align:start position:0% +then in the limit as X goes to Infinity + + + align:start position:0% +then in the limit as X goes to Infinity +it's going to be equal to one + + align:start position:0% +it's going to be equal to one + + + align:start position:0% +it's going to be equal to one +okay + + align:start position:0% +okay + + + align:start position:0% +okay +now I've drawn a CDF for a continuous + + align:start position:0% +now I've drawn a CDF for a continuous + + + align:start position:0% +now I've drawn a CDF for a continuous +random variable this CDF doesn't have + + align:start position:0% +random variable this CDF doesn't have + + + align:start position:0% +random variable this CDF doesn't have +any jumps in it uh a jump occurs in a + + align:start position:0% +any jumps in it uh a jump occurs in a + + + align:start position:0% +any jumps in it uh a jump occurs in a +CDF when there is positive probability + + align:start position:0% +CDF when there is positive probability + + + align:start position:0% +CDF when there is positive probability +that the random variable takes on a + + align:start position:0% +that the random variable takes on a + + + align:start position:0% +that the random variable takes on a +particular value so for continuous + + align:start position:0% +particular value so for continuous + + + align:start position:0% +particular value so for continuous +random variables the cdfs are always + + align:start position:0% +random variables the cdfs are always + + + align:start position:0% +random variables the cdfs are always +going to be smooth for discret random + + align:start position:0% +going to be smooth for discret random + + + align:start position:0% +going to be smooth for discret random +variables they will always have jumps + + align:start position:0% +variables they will always have jumps + + + align:start position:0% +variables they will always have jumps +and for a mixed random variable they + + align:start position:0% +and for a mixed random variable they + + + align:start position:0% +and for a mixed random variable they +could be sort of a mixture of the two so + + align:start position:0% +could be sort of a mixture of the two so + + + align:start position:0% +could be sort of a mixture of the two so +what does a um CDF a maybe a typical CDF + + align:start position:0% +what does a um CDF a maybe a typical CDF + + + align:start position:0% +what does a um CDF a maybe a typical CDF +of + + align:start position:0% + + + + align:start position:0% + +a let me + + align:start position:0% + + + + align:start position:0% + +see oops I went a little too + + align:start position:0% +see oops I went a little too + + + align:start position:0% +see oops I went a little too +high + + align:start position:0% + + + + align:start position:0% + +okay so here this might be a typical CDF + + align:start position:0% +okay so here this might be a typical CDF + + + align:start position:0% +okay so here this might be a typical CDF +for a discrete random variable how + + align:start position:0% + + + + align:start position:0% + +many at how many points does this + + align:start position:0% +many at how many points does this + + + align:start position:0% +many at how many points does this +discrete random variable have positive + + align:start position:0% + + + + align:start position:0% + +probability three points right right + + align:start position:0% +probability three points right right + + + align:start position:0% +probability three points right right +here right here and right + + align:start position:0% +here right here and right + + + align:start position:0% +here right here and right +here okay so basically the the the + + align:start position:0% +here okay so basically the the the + + + align:start position:0% +here okay so basically the the the +cumulative distribution function is + + align:start position:0% +cumulative distribution function is + + + align:start position:0% +cumulative distribution function is +doing precisely what we've what its name + + align:start position:0% +doing precisely what we've what its name + + + align:start position:0% +doing precisely what we've what its name +suggests it would do as you go from sort + + align:start position:0% +suggests it would do as you go from sort + + + align:start position:0% +suggests it would do as you go from sort +of negative Infinity up to P positive + + align:start position:0% +of negative Infinity up to P positive + + + align:start position:0% +of negative Infinity up to P positive +Infinity you're accumulating probability + + align:start position:0% +Infinity you're accumulating probability + + + align:start position:0% +Infinity you're accumulating probability +okay so you can think of maybe the the + + align:start position:0% +okay so you can think of maybe the the + + + align:start position:0% +okay so you can think of maybe the the +probability function kind of sitting in + + align:start position:0% +probability function kind of sitting in + + + align:start position:0% +probability function kind of sitting in +the background of the board and we go + + align:start position:0% +the background of the board and we go + + + align:start position:0% +the background of the board and we go +along and we get to the first point mass + + align:start position:0% +along and we get to the first point mass + + + align:start position:0% +along and we get to the first point mass +in the probability function and then at + + align:start position:0% +in the probability function and then at + + + align:start position:0% +in the probability function and then at +that point the CDF jumps up the uh the + + align:start position:0% +that point the CDF jumps up the uh the + + + align:start position:0% +that point the CDF jumps up the uh the +amount of the size of the point Mass + + align:start position:0% +amount of the size of the point Mass + + + align:start position:0% +amount of the size of the point Mass +okay and then we go along this in this + + align:start position:0% +okay and then we go along this in this + + + align:start position:0% +okay and then we go along this in this +whole region um there's zero probability + + align:start position:0% +whole region um there's zero probability + + + align:start position:0% +whole region um there's zero probability +so we're not accumulating any + + align:start position:0% +so we're not accumulating any + + + align:start position:0% +so we're not accumulating any +probability we get to the second Point + + align:start position:0% +probability we get to the second Point + + + align:start position:0% +probability we get to the second Point +Mass in the probability function and + + align:start position:0% +Mass in the probability function and + + + align:start position:0% +Mass in the probability function and +this is the size of the second Point + + align:start position:0% +this is the size of the second Point + + + align:start position:0% +this is the size of the second Point +Mass so our CDF jump jumps up at that + + align:start position:0% +Mass so our CDF jump jumps up at that + + + align:start position:0% +Mass so our CDF jump jumps up at that +point + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +okay so the the the PF PDF as I said is + + align:start position:0% +okay so the the the PF PDF as I said is + + + align:start position:0% +okay so the the the PF PDF as I said is +a complete description of the + + align:start position:0% +a complete description of the + + + align:start position:0% +a complete description of the +probability the probabilities associated + + align:start position:0% +probability the probabilities associated + + + align:start position:0% +probability the probabilities associated +with a particular random variable the + + align:start position:0% +with a particular random variable the + + + align:start position:0% +with a particular random variable the +CDF is also a complete description of + + align:start position:0% +CDF is also a complete description of + + + align:start position:0% +CDF is also a complete description of +the probabilities associated with a + + align:start position:0% +the probabilities associated with a + + + align:start position:0% +the probabilities associated with a +random variable and so uh in particular + + align:start position:0% +random variable and so uh in particular + + + align:start position:0% +random variable and so uh in particular +particular they contain the same + + align:start position:0% +particular they contain the same + + + align:start position:0% +particular they contain the same +information about its uh distribution + + align:start position:0% +information about its uh distribution + + + align:start position:0% +information about its uh distribution +just in a different form okay so it + + align:start position:0% +just in a different form okay so it + + + align:start position:0% +just in a different form okay so it +stands to reason then that given the PF + + align:start position:0% +stands to reason then that given the PF + + + align:start position:0% +stands to reason then that given the PF +or the PDF one could recover the CDF and + + align:start position:0% +or the PDF one could recover the CDF and + + + align:start position:0% +or the PDF one could recover the CDF and +given the CDF one can recover the PF or + + align:start position:0% +given the CDF one can recover the PF or + + + align:start position:0% +given the CDF one can recover the PF or +the PDF okay so in the case of a um in + + align:start position:0% +the PDF okay so in the case of a um in + + + align:start position:0% +the PDF okay so in the case of a um in +the case of a discret random variable uh + + align:start position:0% +the case of a discret random variable uh + + + align:start position:0% +the case of a discret random variable uh +that can be a fairly simple process so I + + align:start position:0% +that can be a fairly simple process so I + + + align:start position:0% +that can be a fairly simple process so I +just described it up here right so if I + + align:start position:0% +just described it up here right so if I + + + align:start position:0% +just described it up here right so if I +gave you this CDF you would you would be + + align:start position:0% +gave you this CDF you would you would be + + + align:start position:0% +gave you this CDF you would you would be +able to uh draw the PDF or sorry the PF + + align:start position:0% +able to uh draw the PDF or sorry the PF + + + align:start position:0% +able to uh draw the PDF or sorry the PF +you would be able to say their Point + + align:start position:0% +you would be able to say their Point + + + align:start position:0% +you would be able to say their Point +Mass I'd have to label this I guess so + + align:start position:0% +Mass I'd have to label this I guess so + + + align:start position:0% +Mass I'd have to label this I guess so +you'd know where the point masses are + + align:start position:0% +you'd know where the point masses are + + + align:start position:0% +you'd know where the point masses are +but you know there's a point Mass here a + + align:start position:0% +but you know there's a point Mass here a + + + align:start position:0% +but you know there's a point Mass here a +point Mass here a point Mass here and + + align:start position:0% +point Mass here a point Mass here and + + + align:start position:0% +point Mass here a point Mass here and +you'd know how big this one and how big + + align:start position:0% +you'd know how big this one and how big + + + align:start position:0% +you'd know how big this one and how big +this one and how big this one was okay + + align:start position:0% +this one and how big this one was okay + + + align:start position:0% +this one and how big this one was okay +and you'd be done and likewise if I'd + + align:start position:0% +and you'd be done and likewise if I'd + + + align:start position:0% +and you'd be done and likewise if I'd +given you the PF you could have + + align:start position:0% +given you the PF you could have + + + align:start position:0% +given you the PF you could have +constructed this pretty easily for + + align:start position:0% +constructed this pretty easily for + + + align:start position:0% +constructed this pretty easily for +continuous random VAR Ables uh the these + + align:start position:0% +continuous random VAR Ables uh the these + + + align:start position:0% +continuous random VAR Ables uh the these +are the formulas that tell you how to + + align:start position:0% +are the formulas that tell you how to + + + align:start position:0% +are the formulas that tell you how to +move between a PDF and a CDF okay and + + align:start position:0% +move between a PDF and a CDF okay and + + + align:start position:0% +move between a PDF and a CDF okay and +they they intuitively I think make + + align:start position:0% +they they intuitively I think make + + + align:start position:0% +they they intuitively I think make +complete sense they're just the + + align:start position:0% +complete sense they're just the + + + align:start position:0% +complete sense they're just the +continuous analoges of what I described + + align:start position:0% +continuous analoges of what I described + + + align:start position:0% +continuous analoges of what I described +here uh with the the discrete random + + align:start position:0% +here uh with the the discrete random + + + align:start position:0% +here uh with the the discrete random +variables so the if you want to get the + + align:start position:0% +variables so the if you want to get the + + + align:start position:0% +variables so the if you want to get the +uh CDF uh for a continuous random + + align:start position:0% +uh CDF uh for a continuous random + + + align:start position:0% +uh CDF uh for a continuous random +variable at a particular point then you + + align:start position:0% +variable at a particular point then you + + + align:start position:0% +variable at a particular point then you +integrate the PDF up to that point okay + + align:start position:0% +integrate the PDF up to that point okay + + + align:start position:0% +integrate the PDF up to that point okay +and that's what we have + + align:start position:0% +and that's what we have + + + align:start position:0% +and that's what we have +here and if you have the + + align:start position:0% +here and if you have the + + + align:start position:0% +here and if you have the +CDF uh and you want to get the the PDF + + align:start position:0% +CDF uh and you want to get the the PDF + + + align:start position:0% +CDF uh and you want to get the the PDF +you want to recover the PDF from it um + + align:start position:0% +you want to recover the PDF from it um + + + align:start position:0% +you want to recover the PDF from it um +then you take the derivative + + align:start position:0% + + + + align:start position:0% + +okay so does this make sense okay + + align:start position:0% + + + + align:start position:0% + +good okay oh I should say the second + + align:start position:0% +good okay oh I should say the second + + + align:start position:0% +good okay oh I should say the second +I I have to add this disclaimer this is + + align:start position:0% +I I have to add this disclaimer this is + + + align:start position:0% +I I have to add this disclaimer this is +true provided that X is continuous and + + align:start position:0% +true provided that X is continuous and + + + align:start position:0% +true provided that X is continuous and +f-prime exists at all but a finite + + align:start position:0% +f-prime exists at all but a finite + + + align:start position:0% +f-prime exists at all but a finite +number of + + align:start position:0% + + + + align:start position:0% + +points okay + + align:start position:0% +points okay + + + align:start position:0% +points okay +so when we were talking about + + align:start position:0% +so when we were talking about + + + align:start position:0% +so when we were talking about +probability last lecture at some point + + align:start position:0% +probability last lecture at some point + + + align:start position:0% +probability last lecture at some point +during the lecture I said that it was + + align:start position:0% +during the lecture I said that it was + + + align:start position:0% +during the lecture I said that it was +going to be important for us to discuss + + align:start position:0% +going to be important for us to discuss + + + align:start position:0% +going to be important for us to discuss +the + + align:start position:0% +the + + + align:start position:0% +the +relationships uh between stochastic + + align:start position:0% +relationships uh between stochastic + + + align:start position:0% +relationships uh between stochastic +events and then we talked about + + align:start position:0% +events and then we talked about + + + align:start position:0% +events and then we talked about +independence of + + align:start position:0% +independence of + + + align:start position:0% +independence of +of events we talked about conditional + + align:start position:0% +of events we talked about conditional + + + align:start position:0% +of events we talked about conditional +probability and then we sort of segued + + align:start position:0% +probability and then we sort of segued + + + align:start position:0% +probability and then we sort of segued +into Bas theorem and so forth um well + + align:start position:0% +into Bas theorem and so forth um well + + + align:start position:0% +into Bas theorem and so forth um well +we're going to talk about analogous + + align:start position:0% +we're going to talk about analogous + + + align:start position:0% +we're going to talk about analogous +Concepts in the context of random + + align:start position:0% +Concepts in the context of random + + + align:start position:0% +Concepts in the context of random +variables as + + align:start position:0% +variables as + + + align:start position:0% +variables as +well but in order to do that I first + + align:start position:0% +well but in order to do that I first + + + align:start position:0% +well but in order to do that I first +have to define a joint distribution okay + + align:start position:0% +have to define a joint distribution okay + + + align:start position:0% +have to define a joint distribution okay +so in the case where we're only where we + + align:start position:0% +so in the case where we're only where we + + + align:start position:0% +so in the case where we're only where we +only have two random variables where + + align:start position:0% +only have two random variables where + + + align:start position:0% +only have two random variables where +only two random variables are involved + + align:start position:0% +only two random variables are involved + + + align:start position:0% +only two random variables are involved +uh we're going to call that a b variant + + align:start position:0% +uh we're going to call that a b variant + + + align:start position:0% +uh we're going to call that a b variant +distribution we'll see see um sort of uh + + align:start position:0% +distribution we'll see see um sort of uh + + + align:start position:0% +distribution we'll see see um sort of uh +multivariate distributions later on in + + align:start position:0% +multivariate distributions later on in + + + align:start position:0% +multivariate distributions later on in +the + + align:start position:0% +the + + + align:start position:0% +the +semester okay so let me pause now to + + align:start position:0% +semester okay so let me pause now to + + + align:start position:0% +semester okay so let me pause now to +sort of uh give you some indication why + + align:start position:0% +sort of uh give you some indication why + + + align:start position:0% +sort of uh give you some indication why +we care about the relationship between + + align:start position:0% +we care about the relationship between + + + align:start position:0% +we care about the relationship between +random variables well maybe you know + + align:start position:0% +random variables well maybe you know + + + align:start position:0% +random variables well maybe you know +exactly why we do and that's why you're + + align:start position:0% +exactly why we do and that's why you're + + + align:start position:0% +exactly why we do and that's why you're +in this class because that's you know + + align:start position:0% +in this class because that's you know + + + align:start position:0% +in this class because that's you know +sort of much of what we do in uh you + + align:start position:0% +sort of much of what we do in uh you + + + align:start position:0% +sort of much of what we do in uh you +know sort of um much of what we do in + + align:start position:0% +know sort of um much of what we do in + + + align:start position:0% +know sort of um much of what we do in +data analysis is gather sort of + + align:start position:0% +data analysis is gather sort of + + + align:start position:0% +data analysis is gather sort of +repeated um uh you know um repeated + + align:start position:0% +repeated um uh you know um repeated + + + align:start position:0% +repeated um uh you know um repeated +observations from particular joint + + align:start position:0% +observations from particular joint + + + align:start position:0% +observations from particular joint +distributions of random variables to try + + align:start position:0% +distributions of random variables to try + + + align:start position:0% +distributions of random variables to try +to figure out what their relationship is + + align:start position:0% +to figure out what their relationship is + + + align:start position:0% +to figure out what their relationship is +okay so we do this all the time and you + + align:start position:0% +okay so we do this all the time and you + + + align:start position:0% +okay so we do this all the time and you +know maybe you don't need need to be + + align:start position:0% +know maybe you don't need need to be + + + align:start position:0% +know maybe you don't need need to be +convinced but here are a couple of + + align:start position:0% +convinced but here are a couple of + + + align:start position:0% +convinced but here are a couple of +examples of sort of random variables + + align:start position:0% +examples of sort of random variables + + + align:start position:0% +examples of sort of random variables +whose joint distributions we might care + + align:start position:0% +whose joint distributions we might care + + + align:start position:0% +whose joint distributions we might care +about so maybe we're interested in for + + align:start position:0% +about so maybe we're interested in for + + + align:start position:0% +about so maybe we're interested in for +instance uh The Joint distribution of + + align:start position:0% +instance uh The Joint distribution of + + + align:start position:0% +instance uh The Joint distribution of +rainfall and crop growth in a particular + + align:start position:0% +rainfall and crop growth in a particular + + + align:start position:0% +rainfall and crop growth in a particular +um field um maybe we care about the + + align:start position:0% +um field um maybe we care about the + + + align:start position:0% +um field um maybe we care about the +length of the regular checkout line and + + align:start position:0% +length of the regular checkout line and + + + align:start position:0% +length of the regular checkout line and +the length of the Express checkout line + + align:start position:0% +the length of the Express checkout line + + + align:start position:0% +the length of the Express checkout line +and the relationship between those two + + align:start position:0% +and the relationship between those two + + + align:start position:0% +and the relationship between those two +okay so in particular maybe we sort of + + align:start position:0% +okay so in particular maybe we sort of + + + align:start position:0% +okay so in particular maybe we sort of +know what the distribution of the length + + align:start position:0% +know what the distribution of the length + + + align:start position:0% +know what the distribution of the length +of the the Express checkout line is but + + align:start position:0% +of the the Express checkout line is but + + + align:start position:0% +of the the Express checkout line is but +um we want to know what the relationship + + align:start position:0% +um we want to know what the relationship + + + align:start position:0% +um we want to know what the relationship +between that distribution and the + + align:start position:0% +between that distribution and the + + + align:start position:0% +between that distribution and the +distribution of the length of the + + align:start position:0% +distribution of the length of the + + + align:start position:0% +distribution of the length of the +regular checkout line is so we know + + align:start position:0% +regular checkout line is so we know + + + align:start position:0% +regular checkout line is so we know +whether to switch or something like that + + align:start position:0% +whether to switch or something like that + + + align:start position:0% +whether to switch or something like that +um we might also be concerned about you + + align:start position:0% +um we might also be concerned about you + + + align:start position:0% +um we might also be concerned about you +know uh if we're interested in investing + + align:start position:0% +know uh if we're interested in investing + + + align:start position:0% +know uh if we're interested in investing +in a stock we might want to know uh The + + align:start position:0% +in a stock we might want to know uh The + + + align:start position:0% +in a stock we might want to know uh The +Joint distribution of the dollar euro + + align:start position:0% +Joint distribution of the dollar euro + + + align:start position:0% +Joint distribution of the dollar euro +exchange rate and um the stock price of + + align:start position:0% +exchange rate and um the stock price of + + + align:start position:0% +exchange rate and um the stock price of +an exporting firm that would be uh that + + align:start position:0% +an exporting firm that would be uh that + + + align:start position:0% +an exporting firm that would be uh that +would be affected by the fluctuations in + + align:start position:0% +would be affected by the fluctuations in + + + align:start position:0% +would be affected by the fluctuations in +the dollar euro exchange rate okay so + + align:start position:0% +the dollar euro exchange rate okay so + + + align:start position:0% +the dollar euro exchange rate okay so +these are just you know a few examples + + align:start position:0% +these are just you know a few examples + + + align:start position:0% +these are just you know a few examples +from you know + + align:start position:0% +from you know + + + align:start position:0% +from you know +uh an infinite number of examples we + + align:start position:0% +uh an infinite number of examples we + + + align:start position:0% +uh an infinite number of examples we +could come up with for why we care about + + align:start position:0% +could come up with for why we care about + + + align:start position:0% +could come up with for why we care about +joint + + align:start position:0% + + + + align:start position:0% + +distributions okay so now + + align:start position:0% +distributions okay so now + + + align:start position:0% +distributions okay so now +definition If X and Y are continuous + + align:start position:0% +definition If X and Y are continuous + + + align:start position:0% +definition If X and Y are continuous +random variables defined on the same + + align:start position:0% +random variables defined on the same + + + align:start position:0% +random variables defined on the same +sample space + + align:start position:0% +sample space + + + align:start position:0% +sample space +s then the joint probability density + + align:start position:0% +s then the joint probability density + + + align:start position:0% +s then the joint probability density +function of X and Y and this is + + align:start position:0% +function of X and Y and this is + + + align:start position:0% +function of X and Y and this is +denoted little F sub + + align:start position:0% +denoted little F sub + + + align:start position:0% +denoted little F sub +XY is the surface such that for any + + align:start position:0% +XY is the surface such that for any + + + align:start position:0% +XY is the surface such that for any +region of the XY plane the probability + + align:start position:0% +region of the XY plane the probability + + + align:start position:0% +region of the XY plane the probability +that XY is contained in some region a is + + align:start position:0% +that XY is contained in some region a is + + + align:start position:0% +that XY is contained in some region a is +equal to the integral of that function + + align:start position:0% +equal to the integral of that function + + + align:start position:0% +equal to the integral of that function +over the region a okay so it's kind of + + align:start position:0% +over the region a okay so it's kind of + + + align:start position:0% +over the region a okay so it's kind of +the natural generalization of the + + align:start position:0% +the natural generalization of the + + + align:start position:0% +the natural generalization of the +continuous the definition of the + + align:start position:0% +continuous the definition of the + + + align:start position:0% +continuous the definition of the +continuous um PDF uh natural generaliz + + align:start position:0% +continuous um PDF uh natural generaliz + + + align:start position:0% +continuous um PDF uh natural generaliz +ation to two random + + align:start position:0% +ation to two random + + + align:start position:0% +ation to two random +variables okay so here we're just um + + align:start position:0% +variables okay so here we're just um + + + align:start position:0% +variables okay so here we're just um +we've got this this uh function here + + align:start position:0% +we've got this this uh function here + + + align:start position:0% +we've got this this uh function here +this small f is a Surface over the XY + + align:start position:0% +this small f is a Surface over the XY + + + align:start position:0% +this small f is a Surface over the XY +plane and in order to calculate + + align:start position:0% +plane and in order to calculate + + + align:start position:0% +plane and in order to calculate +probabilities we're we're going to um be + + align:start position:0% +probabilities we're we're going to um be + + + align:start position:0% +probabilities we're we're going to um be +integrating over sort of regions of the + + align:start position:0% +integrating over sort of regions of the + + + align:start position:0% +integrating over sort of regions of the +XY plane integrating that surface over + + align:start position:0% +XY plane integrating that surface over + + + align:start position:0% +XY plane integrating that surface over +regions of the XY plane okay + + align:start position:0% +regions of the XY plane okay + + + align:start position:0% +regions of the XY plane okay +so like before properties of probability + + align:start position:0% +so like before properties of probability + + + align:start position:0% +so like before properties of probability +imply certain properties of the joint + + align:start position:0% +imply certain properties of the joint + + + align:start position:0% +imply certain properties of the joint +PDF uh such as uh that it's it's got to + + align:start position:0% +PDF uh such as uh that it's it's got to + + + align:start position:0% +PDF uh such as uh that it's it's got to +integrate to one over the XY plane uh + + align:start position:0% +integrate to one over the XY plane uh + + + align:start position:0% +integrate to one over the XY plane uh +any individual point or onedimensional + + align:start position:0% +any individual point or onedimensional + + + align:start position:0% +any individual point or onedimensional +curve has probability zero um Etc + + align:start position:0% + + + + align:start position:0% + +okay so the analogous uh function exists + + align:start position:0% +okay so the analogous uh function exists + + + align:start position:0% +okay so the analogous uh function exists +for discrete random variables as well + + align:start position:0% +for discrete random variables as well + + + align:start position:0% +for discrete random variables as well +and this is how it's defined okay I'm + + align:start position:0% +and this is how it's defined okay I'm + + + align:start position:0% +and this is how it's defined okay I'm +not going to say any more about it right + + align:start position:0% +not going to say any more about it right + + + align:start position:0% +not going to say any more about it right +now and uh sometimes I'm just going to + + align:start position:0% +now and uh sometimes I'm just going to + + + align:start position:0% +now and uh sometimes I'm just going to +give definitions in terms of in terms of + + align:start position:0% +give definitions in terms of in terms of + + + align:start position:0% +give definitions in terms of in terms of +continuous random + + align:start position:0% + + + + align:start position:0% + +variables + + align:start position:0% + + + + align:start position:0% + +okay okay so now let's uh let's consider + + align:start position:0% +okay okay so now let's uh let's consider + + + align:start position:0% +okay okay so now let's uh let's consider +an example um where we can uh sort of + + align:start position:0% +an example um where we can uh sort of + + + align:start position:0% +an example um where we can uh sort of +play around with a joint distribution so + + align:start position:0% +play around with a joint distribution so + + + align:start position:0% +play around with a joint distribution so +let's suppose that after hours and hours + + align:start position:0% +let's suppose that after hours and hours + + + align:start position:0% +let's suppose that after hours and hours +of writing lecture notes I develop a + + align:start position:0% +of writing lecture notes I develop a + + + align:start position:0% +of writing lecture notes I develop a +splitting headache by the way this is a + + align:start position:0% +splitting headache by the way this is a + + + align:start position:0% +splitting headache by the way this is a +entirely fictional + + align:start position:0% +entirely fictional + + + align:start position:0% +entirely fictional +account um and after developing that uh + + align:start position:0% +account um and after developing that uh + + + align:start position:0% +account um and after developing that uh +fictional headache I rumage around in my + + align:start position:0% +fictional headache I rumage around in my + + + align:start position:0% +fictional headache I rumage around in my +drawer and I find one tablet of neoen + + align:start position:0% +drawer and I find one tablet of neoen + + + align:start position:0% +drawer and I find one tablet of neoen +and one of acetaminophen okay so those + + align:start position:0% +and one of acetaminophen okay so those + + + align:start position:0% +and one of acetaminophen okay so those +are both uh things that one might take + + align:start position:0% +are both uh things that one might take + + + align:start position:0% +are both uh things that one might take +for a headache and by the way I asked my + + align:start position:0% +for a headache and by the way I asked my + + + align:start position:0% +for a headache and by the way I asked my +sister who who uh who is who went to + + align:start position:0% +sister who who uh who is who went to + + + align:start position:0% +sister who who uh who is who went to +medical school whether this was an + + align:start position:0% +medical school whether this was an + + + align:start position:0% +medical school whether this was an +irresponsible example for me to do in + + align:start position:0% +irresponsible example for me to do in + + + align:start position:0% +irresponsible example for me to do in +class and she said she thought it was + + align:start position:0% +class and she said she thought it was + + + align:start position:0% +class and she said she thought it was +fine + + align:start position:0% +fine + + + align:start position:0% +fine +so okay um so I take both the neoen and + + align:start position:0% +so okay um so I take both the neoen and + + + align:start position:0% +so okay um so I take both the neoen and +the acet acetaminophen okay now let X + + align:start position:0% +the acet acetaminophen okay now let X + + + align:start position:0% +the acet acetaminophen okay now let X +random variable X be the effective + + align:start position:0% +random variable X be the effective + + + align:start position:0% +random variable X be the effective +period of the neoen so I've got this + + align:start position:0% +period of the neoen so I've got this + + + align:start position:0% +period of the neoen so I've got this +headache and I take the nioxin and the + + align:start position:0% +headache and I take the nioxin and the + + + align:start position:0% +headache and I take the nioxin and the +the length of time that it it makes the + + align:start position:0% +the length of time that it it makes the + + + align:start position:0% +the length of time that it it makes the +headache go away is X the random + + align:start position:0% +headache go away is X the random + + + align:start position:0% +headache go away is X the random +variable X and let y be the effective + + align:start position:0% +variable X and let y be the effective + + + align:start position:0% +variable X and let y be the effective +period of the acetam + + align:start position:0% +period of the acetam + + + align:start position:0% +period of the acetam +Menan okay and suppose that this is the + + align:start position:0% +Menan okay and suppose that this is the + + + align:start position:0% +Menan okay and suppose that this is the +joint distribution of for X and + + align:start position:0% + + + + align:start position:0% + +Y so I want to ask the following + + align:start position:0% +Y so I want to ask the following + + + align:start position:0% +Y so I want to ask the following +question what's the probability that my + + align:start position:0% +question what's the probability that my + + + align:start position:0% +question what's the probability that my +headache comes back within 3 hours yep + + align:start position:0% +headache comes back within 3 hours yep + + + align:start position:0% +headache comes back within 3 hours yep +do that all depend on the value of + + align:start position:0% +do that all depend on the value of + + + align:start position:0% +do that all depend on the value of +Lambda oh yeah we're going to do all the + + align:start position:0% +Lambda oh yeah we're going to do all the + + + align:start position:0% +Lambda oh yeah we're going to do all the +calculations conditional and Lambda yeah + + align:start position:0% +calculations conditional and Lambda yeah + + + align:start position:0% +calculations conditional and Lambda yeah +I mean I could have put a number in + + align:start position:0% +I mean I could have put a number in + + + align:start position:0% +I mean I could have put a number in +there I don't know maybe I should have + + align:start position:0% +there I don't know maybe I should have + + + align:start position:0% +there I don't know maybe I should have +put a number in there but um yeah no + + align:start position:0% +put a number in there but um yeah no + + + align:start position:0% +put a number in there but um yeah no +we're we'll I I uh decided to just do + + align:start position:0% +we're we'll I I uh decided to just do + + + align:start position:0% +we're we'll I I uh decided to just do +this example in sort of a more General + + align:start position:0% +this example in sort of a more General + + + align:start position:0% +this example in sort of a more General +way and so we'll just do we'll we'll + + align:start position:0% +way and so we'll just do we'll we'll + + + align:start position:0% +way and so we'll just do we'll we'll +calculate all of the probabilities as a + + align:start position:0% +calculate all of the probabilities as a + + + align:start position:0% +calculate all of the probabilities as a +function of Lambda + + align:start position:0% +function of Lambda + + + align:start position:0% +function of Lambda +so so how how would we go about this + + align:start position:0% + + + + align:start position:0% + +yeah so if you integrate that that's the + + align:start position:0% +yeah so if you integrate that that's the + + + align:start position:0% +yeah so if you integrate that that's the +probability + + align:start position:0% +probability + + + align:start position:0% +probability +that so that's like + + align:start position:0% +that so that's like + + + align:start position:0% +that so that's like +the would it be + + align:start position:0% +the would it be + + + align:start position:0% +the would it be +one one minus the integral of of + + align:start position:0% +one one minus the integral of of + + + align:start position:0% +one one minus the integral of of +that so I'm I'm not sure exactly what + + align:start position:0% +that so I'm I'm not sure exactly what + + + align:start position:0% +that so I'm I'm not sure exactly what +you're getting at what what I'm what I'm + + align:start position:0% +you're getting at what what I'm what I'm + + + align:start position:0% +you're getting at what what I'm what I'm +uh sort of wanting you to answer is the + + align:start position:0% +uh sort of wanting you to answer is the + + + align:start position:0% +uh sort of wanting you to answer is the +region over which so you're right that + + align:start position:0% +region over which so you're right that + + + align:start position:0% +region over which so you're right that +we're going to integrate this PD this uh + + align:start position:0% +we're going to integrate this PD this uh + + + align:start position:0% +we're going to integrate this PD this uh +joint PDF to get the + + align:start position:0% +joint PDF to get the + + + align:start position:0% +joint PDF to get the +probability and what I'm uh driving at + + align:start position:0% +probability and what I'm uh driving at + + + align:start position:0% +probability and what I'm uh driving at +is what is the can you characterize the + + align:start position:0% +is what is the can you characterize the + + + align:start position:0% +is what is the can you characterize the +region over which we're going to + + align:start position:0% +region over which we're going to + + + align:start position:0% +region over which we're going to +integrate this joint + + align:start position:0% +integrate this joint + + + align:start position:0% +integrate this joint +PDF yep do 0 to 3 and then take one + + align:start position:0% +PDF yep do 0 to 3 and then take one + + + align:start position:0% +PDF yep do 0 to 3 and then take one +minus the probability of that integrate + + align:start position:0% +minus the probability of that integrate + + + align:start position:0% +minus the probability of that integrate +for 0 to 3 hours integrate so remember + + align:start position:0% +for 0 to 3 hours integrate so remember + + + align:start position:0% +for 0 to 3 hours integrate so remember +this is a Surface this is a Surface over + + align:start position:0% +this is a Surface this is a Surface over + + + align:start position:0% +this is a Surface this is a Surface over +the XY plane So when you say integrate + + align:start position:0% +the XY plane So when you say integrate + + + align:start position:0% +the XY plane So when you say integrate +integ from 0 to three do you mean + + align:start position:0% +integ from 0 to three do you mean + + + align:start position:0% +integ from 0 to three do you mean +in The X Dimension + + align:start position:0% +in The X Dimension + + + align:start position:0% +in The X Dimension +oral yeah a double inter oh okay yeah + + align:start position:0% +oral yeah a double inter oh okay yeah + + + align:start position:0% +oral yeah a double inter oh okay yeah +yeah yeah yeah yeah yeah oh okay yes so + + align:start position:0% +yeah yeah yeah yeah yeah oh okay yes so + + + align:start position:0% +yeah yeah yeah yeah yeah oh okay yes so +the double integral is exactly right + + align:start position:0% +the double integral is exactly right + + + align:start position:0% +the double integral is exactly right +yeah yeah so um so the let me see the + + align:start position:0% +yeah yeah so um so the let me see the + + + align:start position:0% +yeah yeah so um so the let me see the +probability my headache comes back + + align:start position:0% +probability my headache comes back + + + align:start position:0% +probability my headache comes back +within three hours + + align:start position:0% +within three hours + + + align:start position:0% +within three hours +is the yes it's one minus this + + align:start position:0% +is the yes it's one minus this + + + align:start position:0% +is the yes it's one minus this +exactly + + align:start position:0% +exactly + + + align:start position:0% +exactly +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so here here i' I've sort of set up the + + align:start position:0% +so here here i' I've sort of set up the + + + align:start position:0% +so here here i' I've sort of set up the +integral so that you can see exactly + + align:start position:0% +integral so that you can see exactly + + + align:start position:0% +integral so that you can see exactly +what we're doing the probability my + + align:start position:0% +what we're doing the probability my + + + align:start position:0% +what we're doing the probability my +headache comes back within 3 hours so + + align:start position:0% +headache comes back within 3 hours so + + + align:start position:0% +headache comes back within 3 hours so +you're right it should be one minus the + + align:start position:0% +you're right it should be one minus the + + + align:start position:0% +you're right it should be one minus the +probability that X is uh less than or + + align:start position:0% +probability that X is uh less than or + + + align:start position:0% +probability that X is uh less than or +equal to three and Y is less than or + + align:start position:0% +equal to three and Y is less than or + + + align:start position:0% +equal to three and Y is less than or +equal to three okay + + align:start position:0% +equal to three okay + + + align:start position:0% +equal to three okay +yep is it correct because if x is less + + align:start position:0% +yep is it correct because if x is less + + + align:start position:0% +yep is it correct because if x is less +than three and Y is less than three that + + align:start position:0% +than three and Y is less than three that + + + align:start position:0% +than three and Y is less than three that +means the of the medicines are not + + align:start position:0% +means the of the medicines are not + + + align:start position:0% +means the of the medicines are not +effective within the 3 hours and you + + align:start position:0% +effective within the 3 hours and you + + + align:start position:0% +effective within the 3 hours and you +will get a headache right so should be + + align:start position:0% +will get a headache right so should be + + + align:start position:0% +will get a headache right so should be +not + + align:start position:0% +not + + + align:start position:0% +not +one or am I + + align:start position:0% +one or am I + + + align:start position:0% +one or am I +understand sorry okay maybe maybe I got + + align:start position:0% +understand sorry okay maybe maybe I got + + + align:start position:0% +understand sorry okay maybe maybe I got +maybe I've got I've I I'm confused with + + align:start position:0% +maybe I've got I've I I'm confused with + + + align:start position:0% +maybe I've got I've I I'm confused with +the uh the negatives so this is this is + + align:start position:0% +the uh the negatives so this is this is + + + align:start position:0% +the uh the negatives so this is this is +giving me the probability oh yeah no + + align:start position:0% +giving me the probability oh yeah no + + + align:start position:0% +giving me the probability oh yeah no +this is giving me the probability that + + align:start position:0% +this is giving me the probability that + + + align:start position:0% +this is giving me the probability that +um my + + align:start position:0% +um my + + + align:start position:0% +um my +headache will come back yeah yeah yeah + + align:start position:0% +headache will come back yeah yeah yeah + + + align:start position:0% +headache will come back yeah yeah yeah +yeah yeah y sorry about that confusion + + align:start position:0% +yeah yeah y sorry about that confusion + + + align:start position:0% +yeah yeah y sorry about that confusion +okay so the probability that my headache + + align:start position:0% +okay so the probability that my headache + + + align:start position:0% +okay so the probability that my headache +comes back within 3 hours is the the + + align:start position:0% +comes back within 3 hours is the the + + + align:start position:0% +comes back within 3 hours is the the +integral over this region okay and I + + align:start position:0% +integral over this region okay and I + + + align:start position:0% +integral over this region okay and I +have a picture of it as well so we all + + align:start position:0% +have a picture of it as well so we all + + + align:start position:0% +have a picture of it as well so we all +we do is we take the joint PDF okay so + + align:start position:0% +we do is we take the joint PDF okay so + + + align:start position:0% +we do is we take the joint PDF okay so +this is the surface over the XY plane + + align:start position:0% +this is the surface over the XY plane + + + align:start position:0% +this is the surface over the XY plane +and we're integrating from uh we're + + align:start position:0% +and we're integrating from uh we're + + + align:start position:0% +and we're integrating from uh we're +doing the double integral over the + + align:start position:0% +doing the double integral over the + + + align:start position:0% +doing the double integral over the +region the sort of um + + align:start position:0% +region the sort of um + + + align:start position:0% +region the sort of um +3x3 box at the origin + + align:start position:0% +3x3 box at the origin + + + align:start position:0% +3x3 box at the origin +okay and those dots mean that I left out + + align:start position:0% +okay and those dots mean that I left out + + + align:start position:0% +okay and those dots mean that I left out +the intermediate steps but you can work + + align:start position:0% +the intermediate steps but you can work + + + align:start position:0% +the intermediate steps but you can work +on them uh work on the details at home + + align:start position:0% +on them uh work on the details at home + + + align:start position:0% +on them uh work on the details at home +and in fact this is what the this is + + align:start position:0% +and in fact this is what the this is + + + align:start position:0% +and in fact this is what the this is +what you get when you do the double + + align:start position:0% +what you get when you do the double + + + align:start position:0% +what you get when you do the double +integral + + align:start position:0% +integral + + + align:start position:0% +integral +okay and here is a picture this is the + + align:start position:0% +okay and here is a picture this is the + + + align:start position:0% +okay and here is a picture this is the +region uh over which we're integrating + + align:start position:0% +region uh over which we're integrating + + + align:start position:0% +region uh over which we're integrating +okay so if I wanted to draw I'm not sure + + align:start position:0% +okay so if I wanted to draw I'm not sure + + + align:start position:0% +okay so if I wanted to draw I'm not sure +if I can do this in a + + align:start position:0% + + + + align:start position:0% + +very useful way but let me give it a + + align:start position:0% +very useful way but let me give it a + + + align:start position:0% +very useful way but let me give it a +shot so let's see I have X over here and + + align:start position:0% +shot so let's see I have X over here and + + + align:start position:0% +shot so let's see I have X over here and +Y over here and then I have f subx y + + align:start position:0% +Y over here and then I have f subx y + + + align:start position:0% +Y over here and then I have f subx y +here and this is the + + align:start position:0% + + + + align:start position:0% + +region over which we're integrating and + + align:start position:0% +region over which we're integrating and + + + align:start position:0% +region over which we're integrating and +the surface looks something like this + + align:start position:0% + + + + align:start position:0% + +not sure how useful that is + + align:start position:0% +not sure how useful that is + + + align:start position:0% +not sure how useful that is +but and what we want to do is um to + + align:start position:0% +but and what we want to do is um to + + + align:start position:0% +but and what we want to do is um to +calculate the probability just integrate + + align:start position:0% +calculate the probability just integrate + + + align:start position:0% +calculate the probability just integrate +this surface over this area okay + + align:start position:0% + + + + align:start position:0% + +yep uh only only if you want me to get + + align:start position:0% +yep uh only only if you want me to get + + + align:start position:0% +yep uh only only if you want me to get +confused again and scratch my head okay + + align:start position:0% +confused again and scratch my head okay + + + align:start position:0% +confused again and scratch my head okay +so let's go through this + + align:start position:0% + + + + align:start position:0% + +so okay so X is the effective period of + + align:start position:0% +so okay so X is the effective period of + + + align:start position:0% +so okay so X is the effective period of +nioxin so if uh if x is equal to 3 so + + align:start position:0% +nioxin so if uh if x is equal to 3 so + + + align:start position:0% +nioxin so if uh if x is equal to 3 so +let's let's just think about it in terms + + align:start position:0% +let's let's just think about it in terms + + + align:start position:0% +let's let's just think about it in terms +of a of of one dimension okay so if if + + align:start position:0% +of a of of one dimension okay so if if + + + align:start position:0% +of a of of one dimension okay so if if +uh X is equal to three my headache comes + + align:start position:0% +uh X is equal to three my headache comes + + + align:start position:0% +uh X is equal to three my headache comes +back uh in 3 hours okay if my or if x is + + align:start position:0% +back uh in 3 hours okay if my or if x is + + + align:start position:0% +back uh in 3 hours okay if my or if x is +less anything less than three my + + align:start position:0% +less anything less than three my + + + align:start position:0% +less anything less than three my +headache will come back within three + + align:start position:0% +headache will come back within three + + + align:start position:0% +headache will come back within three +hours + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% + + + + align:start position:0% + +okay if you had only one then it will + + align:start position:0% +okay if you had only one then it will + + + align:start position:0% +okay if you had only one then it will +come + + align:start position:0% +come + + + align:start position:0% +come +back + + align:start position:0% +back + + + align:start position:0% +back +if that one is out + + align:start position:0% +if that one is out + + + align:start position:0% +if that one is out +to be less than three but then you + + align:start position:0% +to be less than three but then you + + + align:start position:0% +to be less than three but then you +always have the other one so that's + + align:start position:0% +always have the other one so that's + + + align:start position:0% +always have the other one so that's +youting Square EV have to be + + align:start position:0% + + + + align:start position:0% + +together and perhaps this next example + + align:start position:0% +together and perhaps this next example + + + align:start position:0% +together and perhaps this next example +will so this next example is sort of I'm + + align:start position:0% +will so this next example is sort of I'm + + + align:start position:0% +will so this next example is sort of I'm +changing the question a little bit and + + align:start position:0% +changing the question a little bit and + + + align:start position:0% +changing the question a little bit and +it might clear it actually might clarify + + align:start position:0% +it might clear it actually might clarify + + + align:start position:0% +it might clear it actually might clarify +um the question so or might clarify the + + align:start position:0% +um the question so or might clarify the + + + align:start position:0% +um the question so or might clarify the +previous question + + align:start position:0% +previous question + + + align:start position:0% +previous question +so I'm going to change the question now + + align:start position:0% +so I'm going to change the question now + + + align:start position:0% +so I'm going to change the question now +and ask what if I only took the + + align:start position:0% +and ask what if I only took the + + + align:start position:0% +and ask what if I only took the +acetaminophen after the nepro stopped + + align:start position:0% +acetaminophen after the nepro stopped + + + align:start position:0% +acetaminophen after the nepro stopped +working okay so what uh question what + + align:start position:0% +working okay so what uh question what + + + align:start position:0% +working okay so what uh question what +can we put this in terms of sort of a + + align:start position:0% +can we put this in terms of sort of a + + + align:start position:0% +can we put this in terms of sort of a +question about probability what am I + + align:start position:0% +question about probability what am I + + + align:start position:0% +question about probability what am I +asking + + align:start position:0% +asking + + + align:start position:0% +asking +now + + align:start position:0% +now + + + align:start position:0% +now +y that's right it's the probability that + + align:start position:0% +y that's right it's the probability that + + + align:start position:0% +y that's right it's the probability that +x + y is less than three because I take + + align:start position:0% +x + y is less than three because I take + + + align:start position:0% +x + y is less than three because I take +the neox and as soon as that stops + + align:start position:0% +the neox and as soon as that stops + + + align:start position:0% +the neox and as soon as that stops +working I take the acet acetaminophen so + + align:start position:0% +working I take the acet acetaminophen so + + + align:start position:0% +working I take the acet acetaminophen so +I'm asking the question whether the the + + align:start position:0% +I'm asking the question whether the the + + + align:start position:0% +I'm asking the question whether the the +uh sum of the two lengths is less than + + align:start position:0% +uh sum of the two lengths is less than + + + align:start position:0% +uh sum of the two lengths is less than +or equal to three + + align:start position:0% + + + + align:start position:0% + +okay okay so now the region over which + + align:start position:0% +okay okay so now the region over which + + + align:start position:0% +okay okay so now the region over which +we're going to integrate this surface + + align:start position:0% +we're going to integrate this surface + + + align:start position:0% +we're going to integrate this surface +changes obviously um and uh you know + + align:start position:0% +changes obviously um and uh you know + + + align:start position:0% +changes obviously um and uh you know +this is I've set up the the uh + + align:start position:0% +this is I've set up the the uh + + + align:start position:0% +this is I've set up the the uh +integral but I can also show you the + + align:start position:0% +integral but I can also show you the + + + align:start position:0% +integral but I can also show you the +picture how of how it + + align:start position:0% +picture how of how it + + + align:start position:0% +picture how of how it +changes + + align:start position:0% + + + + align:start position:0% + +okay and so + + align:start position:0% + + + + align:start position:0% + +now yep how do you probability X Y to + + align:start position:0% +now yep how do you probability X Y to + + + align:start position:0% +now yep how do you probability X Y to +that how how do I set up these limits of + + align:start position:0% +that how how do I set up these limits of + + + align:start position:0% +that how how do I set up these limits of +integration well so basically what I'm + + align:start position:0% +integration well so basically what I'm + + + align:start position:0% +integration well so basically what I'm +I'm going to do is I'm going to draw a + + align:start position:0% +I'm going to do is I'm going to draw a + + + align:start position:0% +I'm going to do is I'm going to draw a +line in the XY plane that's def that + + align:start position:0% +line in the XY plane that's def that + + + align:start position:0% +line in the XY plane that's def that +defines sort of x + y being equal to + + align:start position:0% +defines sort of x + y being equal to + + + align:start position:0% +defines sort of x + y being equal to +three and then I've got to set out my + + align:start position:0% +three and then I've got to set out my + + + align:start position:0% +three and then I've got to set out my +limits of integration so this that's + + align:start position:0% +limits of integration so this that's + + + align:start position:0% +limits of integration so this that's +this line here okay and then I've got to + + align:start position:0% +this line here okay and then I've got to + + + align:start position:0% +this line here okay and then I've got to +set out my limits of integration to uh + + align:start position:0% +set out my limits of integration to uh + + + align:start position:0% +set out my limits of integration to uh +to to get that triangle and the the way + + align:start position:0% +to to get that triangle and the the way + + + align:start position:0% +to to get that triangle and the the way +I do it I mean there there's actually + + align:start position:0% +I do it I mean there there's actually + + + align:start position:0% +I do it I mean there there's actually +two different ways to do it but the way + + align:start position:0% +two different ways to do it but the way + + + align:start position:0% +two different ways to do it but the way +I did it was letting X go from 0 to 3 + + align:start position:0% +I did it was letting X go from 0 to 3 + + + align:start position:0% +I did it was letting X go from 0 to 3 +but then when you uh so as X is going + + align:start position:0% +but then when you uh so as X is going + + + align:start position:0% +but then when you uh so as X is going +from 0 to 3 then y uh goes from 0 to 3 - + + align:start position:0% +from 0 to 3 then y uh goes from 0 to 3 - + + + align:start position:0% +from 0 to 3 then y uh goes from 0 to 3 - +x which is which is this line here okay + + align:start position:0% +x which is which is this line here okay + + + align:start position:0% +x which is which is this line here okay +so the the the um the the limits of + + align:start position:0% +so the the the um the the limits of + + + align:start position:0% +so the the the um the the limits of +integration for y depend on X because + + align:start position:0% +integration for y depend on X because + + + align:start position:0% +integration for y depend on X because +it's a triangle and you know you can + + align:start position:0% +it's a triangle and you know you can + + + align:start position:0% +it's a triangle and you know you can +sort of look for each for each value of + + align:start position:0% +sort of look for each for each value of + + + align:start position:0% +sort of look for each for each value of +x what uh the limits of integration for + + align:start position:0% +x what uh the limits of integration for + + + align:start position:0% +x what uh the limits of integration for +y will be does that make sense so I + + align:start position:0% +y will be does that make sense so I + + + align:start position:0% +y will be does that make sense so I +could have done it the other you know I + + align:start position:0% +could have done it the other you know I + + + align:start position:0% +could have done it the other you know I +could have switched the the order of + + align:start position:0% +could have switched the the order of + + + align:start position:0% +could have switched the the order of +integration and I would have had + + align:start position:0% +integration and I would have had + + + align:start position:0% +integration and I would have had +different limits and would have gotten + + align:start position:0% +different limits and would have gotten + + + align:start position:0% +different limits and would have gotten +the same + + align:start position:0% +the same + + + align:start position:0% +the same +answer + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +yep might be a weird question but it + + align:start position:0% +yep might be a weird question but it + + + align:start position:0% +yep might be a weird question but it +seems like to get these two The Joint + + align:start position:0% +seems like to get these two The Joint + + + align:start position:0% +seems like to get these two The Joint +probability just multiplying each + + align:start position:0% +probability just multiplying each + + + align:start position:0% +probability just multiplying each +individual + + align:start position:0% +individual + + + align:start position:0% +individual +probability well you're a step ahead of + + align:start position:0% +probability well you're a step ahead of + + + align:start position:0% +probability well you're a step ahead of +us actually so so so actually that no + + align:start position:0% +us actually so so so actually that no + + + align:start position:0% +us actually so so so actually that no +you're absolutely right and that's a + + align:start position:0% +you're absolutely right and that's a + + + align:start position:0% +you're absolutely right and that's a +that's a um an astute observation um and + + align:start position:0% +that's a um an astute observation um and + + + align:start position:0% +that's a um an astute observation um and +basically this the that means that this + + align:start position:0% +basically this the that means that this + + + align:start position:0% +basically this the that means that this +joint probability is the result of two + + align:start position:0% +joint probability is the result of two + + + align:start position:0% +joint probability is the result of two +uh random variables that are that are + + align:start position:0% +uh random variables that are that are + + + align:start position:0% +uh random variables that are that are +independent and this that's how you get + + align:start position:0% +independent and this that's how you get + + + align:start position:0% +independent and this that's how you get +joint distributions of independent + + align:start position:0% +joint distributions of independent + + + align:start position:0% +joint distributions of independent +random variables is you multiply their + + align:start position:0% +random variables is you multiply their + + + align:start position:0% +random variables is you multiply their +individual uh distributions together + + align:start position:0% +individual uh distributions together + + + align:start position:0% +individual uh distributions together +okay so we didn't you didn't have have + + align:start position:0% +okay so we didn't you didn't have have + + + align:start position:0% +okay so we didn't you didn't have have +to know that for this example I just + + align:start position:0% +to know that for this example I just + + + align:start position:0% +to know that for this example I just +gave you the joint distribution but if + + align:start position:0% +gave you the joint distribution but if + + + align:start position:0% +gave you the joint distribution but if +you knew about independence of random + + align:start position:0% +you knew about independence of random + + + align:start position:0% +you knew about independence of random +variables and you knew how to get joint + + align:start position:0% +variables and you knew how to get joint + + + align:start position:0% +variables and you knew how to get joint +distributions when they were independent + + align:start position:0% +distributions when they were independent + + + align:start position:0% +distributions when they were independent +then I could have given you the + + align:start position:0% +then I could have given you the + + + align:start position:0% +then I could have given you the +individual distributions and you know + + align:start position:0% +individual distributions and you know + + + align:start position:0% +individual distributions and you know +then you could have uh you know computed + + align:start position:0% +then you could have uh you know computed + + + align:start position:0% +then you could have uh you know computed +what the The Joint distribution was and + + align:start position:0% +what the The Joint distribution was and + + + align:start position:0% +what the The Joint distribution was and +then done the problem like that + + align:start position:0% +then done the problem like that + + + align:start position:0% +then done the problem like that +y okay so let's + + align:start position:0% +y okay so let's + + + align:start position:0% +y okay so let's +see okay so one uh one sort of final and + + align:start position:0% +see okay so one uh one sort of final and + + + align:start position:0% +see okay so one uh one sort of final and +important point I want to make about + + align:start position:0% +important point I want to make about + + + align:start position:0% +important point I want to make about +this uh + + align:start position:0% +this uh + + + align:start position:0% +this uh +example is that this example sort of + + align:start position:0% +example is that this example sort of + + + align:start position:0% +example is that this example sort of +suggests something very powerful that we + + align:start position:0% +suggests something very powerful that we + + + align:start position:0% +suggests something very powerful that we +can do with um uh random variables so + + align:start position:0% +can do with um uh random variables so + + + align:start position:0% +can do with um uh random variables so +let's suppose I want to define a new + + align:start position:0% +let's suppose I want to define a new + + + align:start position:0% +let's suppose I want to define a new +random variable and I call my random + + align:start position:0% +random variable and I call my random + + + align:start position:0% +random variable and I call my random +variable + + align:start position:0% +variable + + + align:start position:0% +variable +Z and that's the total effective life of + + align:start position:0% +Z and that's the total effective life of + + + align:start position:0% +Z and that's the total effective life of +the Naproxin and the acetam menen taken + + align:start position:0% +the Naproxin and the acetam menen taken + + + align:start position:0% +the Naproxin and the acetam menen taken +sequentially okay so I mean that's a + + align:start position:0% +sequentially okay so I mean that's a + + + align:start position:0% +sequentially okay so I mean that's a +it's a certainly a reasonable uh random + + align:start position:0% +it's a certainly a reasonable uh random + + + align:start position:0% +it's a certainly a reasonable uh random +variable to Define how could I start to + + align:start position:0% +variable to Define how could I start to + + + align:start position:0% +variable to Define how could I start to +think about how that random variable is + + align:start position:0% +think about how that random variable is + + + align:start position:0% +think about how that random variable is +distributed well in fact we've already + + align:start position:0% +distributed well in fact we've already + + + align:start position:0% +distributed well in fact we've already +figured out exactly how it's distributed + + align:start position:0% +figured out exactly how it's distributed + + + align:start position:0% +figured out exactly how it's distributed +right so were you going to say no Okay + + align:start position:0% +right so were you going to say no Okay + + + align:start position:0% +right so were you going to say no Okay +so we've we've actually already figured + + align:start position:0% +so we've we've actually already figured + + + align:start position:0% +so we've we've actually already figured +out how it's distributed so um the the + + align:start position:0% +out how it's distributed so um the the + + + align:start position:0% +out how it's distributed so um the the +CDF of the new random variable by + + align:start position:0% +CDF of the new random variable by + + + align:start position:0% +CDF of the new random variable by +definition is just equal to the + + align:start position:0% +definition is just equal to the + + + align:start position:0% +definition is just equal to the +probability that Z is less than little + + align:start position:0% +probability that Z is less than little + + + align:start position:0% +probability that Z is less than little +Z okay it's just the definition of a + + align:start position:0% +Z okay it's just the definition of a + + + align:start position:0% +Z okay it's just the definition of a +CDF that is equal to by definition of + + align:start position:0% +CDF that is equal to by definition of + + + align:start position:0% +CDF that is equal to by definition of +our random our new random variable + + align:start position:0% +our random our new random variable + + + align:start position:0% +our random our new random variable +that's equal to the probability that x + + + align:start position:0% +that's equal to the probability that x + + + + align:start position:0% +that's equal to the probability that x + +y is less than or equal to little Z + + align:start position:0% +y is less than or equal to little Z + + + align:start position:0% +y is less than or equal to little Z +okay and that is equal to that quantity + + align:start position:0% +okay and that is equal to that quantity + + + align:start position:0% +okay and that is equal to that quantity +which we just computed okay for Z + + align:start position:0% +which we just computed okay for Z + + + align:start position:0% +which we just computed okay for Z +greater than zero + + align:start position:0% + + + + align:start position:0% + +and so once we've got the CDF of this + + align:start position:0% +and so once we've got the CDF of this + + + align:start position:0% +and so once we've got the CDF of this +new random variable Z then we know that + + align:start position:0% +new random variable Z then we know that + + + align:start position:0% +new random variable Z then we know that +we can also get the PDF of the new + + align:start position:0% +we can also get the PDF of the new + + + align:start position:0% +we can also get the PDF of the new +random variable Z okay and how do we do + + align:start position:0% +random variable Z okay and how do we do + + + align:start position:0% +random variable Z okay and how do we do +that well we just take the derivative + + align:start position:0% +that well we just take the derivative + + + align:start position:0% +that well we just take the derivative +okay so the PDF of this new random + + align:start position:0% +okay so the PDF of this new random + + + align:start position:0% +okay so the PDF of this new random +variable is just equal to uh Lambda + + align:start position:0% +variable is just equal to uh Lambda + + + align:start position:0% +variable is just equal to uh Lambda +squared z uh time e to the negative Z + + align:start position:0% +squared z uh time e to the negative Z + + + align:start position:0% +squared z uh time e to the negative Z +Lambda okay + + align:start position:0% + + + + align:start position:0% + +okay so the the the reason why this is a + + align:start position:0% +okay so the the the reason why this is a + + + align:start position:0% +okay so the the the reason why this is a +a a very important um example and sort + + align:start position:0% +a a very important um example and sort + + + align:start position:0% +a a very important um example and sort +of the concepts embodied in it are going + + align:start position:0% +of the concepts embodied in it are going + + + align:start position:0% +of the concepts embodied in it are going +to come up many times over the course of + + align:start position:0% +to come up many times over the course of + + + align:start position:0% +to come up many times over the course of +the semester the reason why it's so + + align:start position:0% +the semester the reason why it's so + + + align:start position:0% +the semester the reason why it's so +important is that when we start studying + + align:start position:0% +important is that when we start studying + + + align:start position:0% +important is that when we start studying +statistics statistics are a statistic is + + align:start position:0% +statistics statistics are a statistic is + + + align:start position:0% +statistics statistics are a statistic is +nothing other than functions of random + + align:start position:0% +nothing other than functions of random + + + align:start position:0% +nothing other than functions of random +variables that's what statistic is and + + align:start position:0% +variables that's what statistic is and + + + align:start position:0% +variables that's what statistic is and +so if we want to understand how + + align:start position:0% +so if we want to understand how + + + align:start position:0% +so if we want to understand how +statistics behave we have to understand + + align:start position:0% +statistics behave we have to understand + + + align:start position:0% +statistics behave we have to understand +how functions of random variables behave + + align:start position:0% +how functions of random variables behave + + + align:start position:0% +how functions of random variables behave +and this is the first step we're going + + align:start position:0% +and this is the first step we're going + + + align:start position:0% +and this is the first step we're going +to take towards this this is just one + + align:start position:0% +to take towards this this is just one + + + align:start position:0% +to take towards this this is just one +example but this lets us know that if we + + align:start position:0% +example but this lets us know that if we + + + align:start position:0% +example but this lets us know that if we +have two random variables and we uh X + + align:start position:0% +have two random variables and we uh X + + + align:start position:0% +have two random variables and we uh X +and Y and we know how they're + + align:start position:0% +and Y and we know how they're + + + align:start position:0% +and Y and we know how they're +distributed uh we have some hope of + + align:start position:0% +distributed uh we have some hope of + + + align:start position:0% +distributed uh we have some hope of +figuring out out how some arbitrary + + align:start position:0% +figuring out out how some arbitrary + + + align:start position:0% +figuring out out how some arbitrary +function of them is also distributed and + + align:start position:0% +function of them is also distributed and + + + align:start position:0% +function of them is also distributed and +in fact we're you know typically going + + align:start position:0% +in fact we're you know typically going + + + align:start position:0% +in fact we're you know typically going +to be able to figure out how the sum of + + align:start position:0% +to be able to figure out how the sum of + + + align:start position:0% +to be able to figure out how the sum of +random variables is distributed um and + + align:start position:0% +random variables is distributed um and + + + align:start position:0% +random variables is distributed um and +that's going to be very useful for us + + align:start position:0% +that's going to be very useful for us + + + align:start position:0% +that's going to be very useful for us +okay and so uh you know that's sort of + + align:start position:0% +okay and so uh you know that's sort of + + + align:start position:0% +okay and so uh you know that's sort of +um uh you know one reason why I like + + align:start position:0% +um uh you know one reason why I like + + + align:start position:0% +um uh you know one reason why I like +this example a lot is to sort of make + + align:start position:0% +this example a lot is to sort of make + + + align:start position:0% +this example a lot is to sort of make +the point um that you know that that uh + + align:start position:0% +the point um that you know that that uh + + + align:start position:0% +the point um that you know that that uh +we can with the with the tools we have + + align:start position:0% +we can with the with the tools we have + + + align:start position:0% +we can with the with the tools we have +already uh start thinking about how to + + align:start position:0% +already uh start thinking about how to + + + align:start position:0% +already uh start thinking about how to +deal with function of random + + align:start position:0% +deal with function of random + + + align:start position:0% +deal with function of random +variables + + align:start position:0% + + + + align:start position:0% + +okay \ No newline at end of file diff --git a/R8k2x5qJgO4.txt b/R8k2x5qJgO4.txt new file mode 100644 index 0000000000000000000000000000000000000000..e5b8612db72811d0e8e8dddb079043badea21dac --- /dev/null +++ b/R8k2x5qJgO4.txt @@ -0,0 +1,12371 @@ +align:start position:0% + +welcome everyone + + align:start position:0% +welcome everyone + + + align:start position:0% +welcome everyone +try to start on time are there any + + align:start position:0% +try to start on time are there any + + + align:start position:0% +try to start on time are there any +questions from last time + + align:start position:0% +questions from last time + + + align:start position:0% +questions from last time +okay we'll take a look at the + + align:start position:0% +okay we'll take a look at the + + + align:start position:0% +okay we'll take a look at the +class syllabus um we did a theory + + align:start position:0% +class syllabus um we did a theory + + + align:start position:0% +class syllabus um we did a theory +lecture on borisian equilibria and two + + align:start position:0% +lecture on borisian equilibria and two + + + align:start position:0% +lecture on borisian equilibria and two +by two by two + + align:start position:0% +by two by two + + + align:start position:0% +by two by two +trade models in theory last class + + align:start position:0% +trade models in theory last class + + + align:start position:0% +trade models in theory last class +today we're going to begin the first of + + align:start position:0% +today we're going to begin the first of + + + align:start position:0% +today we're going to begin the first of +two applications of that you can see in + + align:start position:0% +two applications of that you can see in + + + align:start position:0% +two applications of that you can see in +fact on the reading list + + align:start position:0% +fact on the reading list + + + align:start position:0% +fact on the reading list +the papers for today which includes this + + align:start position:0% +the papers for today which includes this + + + align:start position:0% +the papers for today which includes this +thing with my thai colleague archer watt + + align:start position:0% +thing with my thai colleague archer watt + + + align:start position:0% +thing with my thai colleague archer watt +which is taking the theory model back to + + align:start position:0% +which is taking the theory model back to + + + align:start position:0% +which is taking the theory model back to +the thai applications + + align:start position:0% +the thai applications + + + align:start position:0% +the thai applications +and there's an additional star reading + + align:start position:0% +and there's an additional star reading + + + align:start position:0% +and there's an additional star reading +here + + align:start position:0% +here + + + align:start position:0% +here +dawkins which is calibration which we + + align:start position:0% +dawkins which is calibration which we + + + align:start position:0% +dawkins which is calibration which we +have done before with the medieval + + align:start position:0% +have done before with the medieval + + + align:start position:0% +have done before with the medieval +villages and dynamics and today we're + + align:start position:0% +villages and dynamics and today we're + + + align:start position:0% +villages and dynamics and today we're +going to do it again but that starred + + align:start position:0% +going to do it again but that starred + + + align:start position:0% +going to do it again but that starred +reading does not appear anywhere + + align:start position:0% +reading does not appear anywhere + + + align:start position:0% +reading does not appear anywhere +particularly in the lectures but still + + align:start position:0% +particularly in the lectures but still + + + align:start position:0% +particularly in the lectures but still +there aren't a lot of new theorems and + + align:start position:0% +there aren't a lot of new theorems and + + + align:start position:0% +there aren't a lot of new theorems and +stuff in the lecture today mostly + + align:start position:0% +stuff in the lecture today mostly + + + align:start position:0% +stuff in the lecture today mostly +concepts so i think you can + + align:start position:0% +concepts so i think you can + + + align:start position:0% +concepts so i think you can +get some time to look at the doc and + + align:start position:0% +get some time to look at the doc and + + + align:start position:0% +get some time to look at the doc and +start article + + align:start position:0% +start article + + + align:start position:0% +start article +and + + align:start position:0% +and + + + align:start position:0% +and +on the class schedule + + align:start position:0% +on the class schedule + + + align:start position:0% +on the class schedule +so after the trade today trade lecture + + align:start position:0% +so after the trade today trade lecture + + + align:start position:0% +so after the trade today trade lecture +application today and the one next + + align:start position:0% +application today and the one next + + + align:start position:0% +application today and the one next +thursday + + align:start position:0% +thursday + + + align:start position:0% +thursday +and then the following week on tuesday + + align:start position:0% +and then the following week on tuesday + + + align:start position:0% +and then the following week on tuesday +i'll conduct with you a review session + + align:start position:0% +i'll conduct with you a review session + + + align:start position:0% +i'll conduct with you a review session +of the material covered in the last one + + align:start position:0% +of the material covered in the last one + + + align:start position:0% +of the material covered in the last one +third of the class + + align:start position:0% +third of the class + + + align:start position:0% +third of the class +so that's the way the schedule looks + + align:start position:0% +so that's the way the schedule looks + + + align:start position:0% +so that's the way the schedule looks +again let me + + align:start position:0% +again let me + + + align:start position:0% +again let me +ask if there are questions otherwise i'm + + align:start position:0% +ask if there are questions otherwise i'm + + + align:start position:0% +ask if there are questions otherwise i'm +going to turn to the study guide in + + align:start position:0% +going to turn to the study guide in + + + align:start position:0% +going to turn to the study guide in +particular + + align:start position:0% +particular + + + align:start position:0% +particular +the + + align:start position:0% +the + + + align:start position:0% +the +material from last time lecture 13. + + align:start position:0% +material from last time lecture 13. + + + align:start position:0% +material from last time lecture 13. +so + + align:start position:0% +so + + + align:start position:0% +so +the first + + align:start position:0% +the first + + + align:start position:0% +the first +review question was in addition to + + align:start position:0% +review question was in addition to + + + align:start position:0% +review question was in addition to +reviewing what it takes + + align:start position:0% +reviewing what it takes + + + align:start position:0% +reviewing what it takes +in general equilibrium terms to describe + + align:start position:0% +in general equilibrium terms to describe + + + align:start position:0% +in general equilibrium terms to describe +an economy + + align:start position:0% +an economy + + + align:start position:0% +an economy +what additional features do we need + + align:start position:0% +what additional features do we need + + + align:start position:0% +what additional features do we need +to put in there to describe a private + + align:start position:0% +to put in there to describe a private + + + align:start position:0% +to put in there to describe a private +ownership + + align:start position:0% +ownership + + + align:start position:0% +ownership +economy + + align:start position:0% +economy + + + align:start position:0% +economy +and let me see + + align:start position:0% +and let me see + + + align:start position:0% +and let me see +if + + align:start position:0% +if + + + align:start position:0% +if +texan do you want to take a stab at that + + align:start position:0% + + + + align:start position:0% + +uh yeah so + + align:start position:0% +uh yeah so + + + align:start position:0% +uh yeah so +for a general equilibrium economy we + + align:start position:0% +for a general equilibrium economy we + + + align:start position:0% +for a general equilibrium economy we +need like the consumers like preferences + + align:start position:0% +need like the consumers like preferences + + + align:start position:0% +need like the consumers like preferences +and consumption set + + align:start position:0% +and consumption set + + + align:start position:0% +and consumption set +the firm technology + + align:start position:0% +the firm technology + + + align:start position:0% +the firm technology +um which is the production set and then + + align:start position:0% +um which is the production set and then + + + align:start position:0% +um which is the production set and then +like + + align:start position:0% +like + + + align:start position:0% +like +economy resources + + align:start position:0% +economy resources + + + align:start position:0% +economy resources +um which is endowment + + align:start position:0% +um which is endowment + + + align:start position:0% +um which is endowment +but + + align:start position:0% +but + + + align:start position:0% +but +additionally for the private ownership + + align:start position:0% +additionally for the private ownership + + + align:start position:0% +additionally for the private ownership +we need each consumer has their own + + align:start position:0% +we need each consumer has their own + + + align:start position:0% +we need each consumer has their own +endowment + + align:start position:0% +endowment + + + align:start position:0% +endowment +um and also each consumer has like + + align:start position:0% +um and also each consumer has like + + + align:start position:0% +um and also each consumer has like +complete ownership of like + + align:start position:0% +complete ownership of like + + + align:start position:0% +complete ownership of like +the firm so the + + align:start position:0% +the firm so the + + + align:start position:0% +the firm so the +the firm is made out of like consumer + + align:start position:0% +the firm is made out of like consumer + + + align:start position:0% +the firm is made out of like consumer +ownership + + align:start position:0% +ownership + + + align:start position:0% +ownership +good okay yeah each consumer has shares + + align:start position:0% +good okay yeah each consumer has shares + + + align:start position:0% +good okay yeah each consumer has shares +in firms so those were the theta i j + + align:start position:0% +in firms so those were the theta i j + + + align:start position:0% +in firms so those were the theta i j +parameters + + align:start position:0% +parameters + + + align:start position:0% +parameters +so that the + + align:start position:0% +so that the + + + align:start position:0% +so that the +if there are profits as in decreasing + + align:start position:0% +if there are profits as in decreasing + + + align:start position:0% +if there are profits as in decreasing +returns to scale those profits + + align:start position:0% +returns to scale those profits + + + align:start position:0% +returns to scale those profits +get distributed back to households + + align:start position:0% +get distributed back to households + + + align:start position:0% +get distributed back to households +so they own the returns on the firms + + align:start position:0% +so they own the returns on the firms + + + align:start position:0% +so they own the returns on the firms +that's a great answer thank you so much + + align:start position:0% +that's a great answer thank you so much + + + align:start position:0% +that's a great answer thank you so much +um + + align:start position:0% +um + + + align:start position:0% +um +what is the potential difference between + + align:start position:0% +what is the potential difference between + + + align:start position:0% +what is the potential difference between +a volrasian equilibrium + + align:start position:0% +a volrasian equilibrium + + + align:start position:0% +a volrasian equilibrium +and + + align:start position:0% +and + + + align:start position:0% +and +a price equilibrium with transfers + + align:start position:0% +a price equilibrium with transfers + + + align:start position:0% +a price equilibrium with transfers +maria sophia do you want to try that one + + align:start position:0% +maria sophia do you want to try that one + + + align:start position:0% +maria sophia do you want to try that one +yeah so + + align:start position:0% +yeah so + + + align:start position:0% +yeah so +um with the price equilibrium with + + align:start position:0% +um with the price equilibrium with + + + align:start position:0% +um with the price equilibrium with +transfers we're looking to see if there + + align:start position:0% +transfers we're looking to see if there + + + align:start position:0% +transfers we're looking to see if there +like exists an assignment + + align:start position:0% +like exists an assignment + + + align:start position:0% +like exists an assignment +um like of wealth levels + + align:start position:0% +um like of wealth levels + + + align:start position:0% +um like of wealth levels +such that the economy will satisfy like + + align:start position:0% +such that the economy will satisfy like + + + align:start position:0% +such that the economy will satisfy like +a set of constraints but in general like + + align:start position:0% +a set of constraints but in general like + + + align:start position:0% +a set of constraints but in general like +a while raising equilibrium + + align:start position:0% +a while raising equilibrium + + + align:start position:0% +a while raising equilibrium +like is a type of price equilibrium with + + align:start position:0% +like is a type of price equilibrium with + + + align:start position:0% +like is a type of price equilibrium with +transfers + + align:start position:0% +transfers + + + align:start position:0% +transfers +um + + align:start position:0% +um + + + align:start position:0% +um +except like we have the condition that + + align:start position:0% +except like we have the condition that + + + align:start position:0% +except like we have the condition that +the wealth is equal to + + align:start position:0% +the wealth is equal to + + + align:start position:0% +the wealth is equal to +um i think it's like the price times the + + align:start position:0% +um i think it's like the price times the + + + align:start position:0% +um i think it's like the price times the +wealth plus the sum of like the profits + + align:start position:0% +wealth plus the sum of like the profits + + + align:start position:0% +wealth plus the sum of like the profits +over + + align:start position:0% +over + + + align:start position:0% +over +the shares that the consumer has in + + align:start position:0% +the shares that the consumer has in + + + align:start position:0% +the shares that the consumer has in +various companies + + align:start position:0% +various companies + + + align:start position:0% +various companies +yes that's right + + align:start position:0% +yes that's right + + + align:start position:0% +yes that's right +so the variant equilibrium + + align:start position:0% +so the variant equilibrium + + + align:start position:0% +so the variant equilibrium +works off of this private ownership + + align:start position:0% +works off of this private ownership + + + align:start position:0% +works off of this private ownership +economy so we have the valuation of the + + align:start position:0% +economy so we have the valuation of the + + + align:start position:0% +economy so we have the valuation of the +household's endowment plus + + align:start position:0% +household's endowment plus + + + align:start position:0% +household's endowment plus +the valuation of the profits that the + + align:start position:0% +the valuation of the profits that the + + + align:start position:0% +the valuation of the profits that the +household + + align:start position:0% +household + + + align:start position:0% +household +has a claim to on the + + align:start position:0% +has a claim to on the + + + align:start position:0% +has a claim to on the +and that is a wealth object + + align:start position:0% +and that is a wealth object + + + align:start position:0% +and that is a wealth object +so technically + + align:start position:0% +so technically + + + align:start position:0% +so technically +it looks like a price equilibrium with + + align:start position:0% +it looks like a price equilibrium with + + + align:start position:0% +it looks like a price equilibrium with +transfers meaning that + + align:start position:0% +transfers meaning that + + + align:start position:0% +transfers meaning that +if we assign that particular wealth + + align:start position:0% +if we assign that particular wealth + + + align:start position:0% +if we assign that particular wealth +we're going to have an equilibrium + + align:start position:0% +we're going to have an equilibrium + + + align:start position:0% +we're going to have an equilibrium +the more general idea behind + + align:start position:0% +the more general idea behind + + + align:start position:0% +the more general idea behind +the price equilibrium is with transfers + + align:start position:0% +the price equilibrium is with transfers + + + align:start position:0% +the price equilibrium is with transfers +though + + align:start position:0% +though + + + align:start position:0% +though +including the transfers part + + align:start position:0% +including the transfers part + + + align:start position:0% +including the transfers part +is that the wealth assignments that we + + align:start position:0% +is that the wealth assignments that we + + + align:start position:0% +is that the wealth assignments that we +give to households + + align:start position:0% +give to households + + + align:start position:0% +give to households +may be greater or less than the va + + align:start position:0% +may be greater or less than the va + + + align:start position:0% +may be greater or less than the va +valuation of the wealth they would have + + align:start position:0% +valuation of the wealth they would have + + + align:start position:0% +valuation of the wealth they would have +had + + align:start position:0% +had + + + align:start position:0% +had +if we had restricted ourselves to + + align:start position:0% +if we had restricted ourselves to + + + align:start position:0% +if we had restricted ourselves to +private ownership + + align:start position:0% + + + + align:start position:0% + +so what i didn't i guess emphasized very + + align:start position:0% +so what i didn't i guess emphasized very + + + align:start position:0% +so what i didn't i guess emphasized very +much + + align:start position:0% +much + + + align:start position:0% +much +is there are going to be two welfare + + align:start position:0% +is there are going to be two welfare + + + align:start position:0% +is there are going to be two welfare +theorems that we will study in detail + + align:start position:0% +theorems that we will study in detail + + + align:start position:0% +theorems that we will study in detail +one is that the volrasian equilibrium is + + align:start position:0% +one is that the volrasian equilibrium is + + + align:start position:0% +one is that the volrasian equilibrium is +pareto optimal + + align:start position:0% +pareto optimal + + + align:start position:0% +pareto optimal +um + + align:start position:0% +um + + + align:start position:0% +um +and for that part we need + + align:start position:0% +and for that part we need + + + align:start position:0% +and for that part we need +private ownership only and the second is + + align:start position:0% +private ownership only and the second is + + + align:start position:0% +private ownership only and the second is +going to be that + + align:start position:0% +going to be that + + + align:start position:0% +going to be that +that any pareto optimal allocation can + + align:start position:0% +that any pareto optimal allocation can + + + align:start position:0% +that any pareto optimal allocation can +be achieved with a suitable distribution + + align:start position:0% +be achieved with a suitable distribution + + + align:start position:0% +be achieved with a suitable distribution +of redistribution of wealth + + align:start position:0% +of redistribution of wealth + + + align:start position:0% +of redistribution of wealth +and that's the part where we're going to + + align:start position:0% +and that's the part where we're going to + + + align:start position:0% +and that's the part where we're going to +need this more general + + align:start position:0% +need this more general + + + align:start position:0% +need this more general +concept of price equilibrium with + + align:start position:0% +concept of price equilibrium with + + + align:start position:0% +concept of price equilibrium with +transfers + + align:start position:0% + + + + align:start position:0% + +the + + align:start position:0% +the + + + align:start position:0% +the +the ordering of the class + + align:start position:0% +the ordering of the class + + + align:start position:0% +the ordering of the class +was to introduce the small raisin + + align:start position:0% +was to introduce the small raisin + + + align:start position:0% +was to introduce the small raisin +equilibrium notion not dwell on the + + align:start position:0% +equilibrium notion not dwell on the + + + align:start position:0% +equilibrium notion not dwell on the +optimality of it + + align:start position:0% +optimality of it + + + align:start position:0% +optimality of it +um + + align:start position:0% +um + + + align:start position:0% +um +but rather get into some applications + + align:start position:0% +but rather get into some applications + + + align:start position:0% +but rather get into some applications +and then + + align:start position:0% +and then + + + align:start position:0% +and then +in a couple of weeks we'll be back to + + align:start position:0% +in a couple of weeks we'll be back to + + + align:start position:0% +in a couple of weeks we'll be back to +those welfare theorems and when they are + + align:start position:0% +those welfare theorems and when they are + + + align:start position:0% +those welfare theorems and when they are +true and when they can fail + + align:start position:0% +true and when they can fail + + + align:start position:0% +true and when they can fail +so that's the ordering of the class + + align:start position:0% +so that's the ordering of the class + + + align:start position:0% +so that's the ordering of the class +and + + align:start position:0% + + + + align:start position:0% + +we got into the two by two by two + + align:start position:0% +we got into the two by two by two + + + align:start position:0% +we got into the two by two by two +all of this stuff at the beginning is + + align:start position:0% +all of this stuff at the beginning is + + + align:start position:0% +all of this stuff at the beginning is +kind of a review + + align:start position:0% +kind of a review + + + align:start position:0% +kind of a review +of the notation + + align:start position:0% +of the notation + + + align:start position:0% +of the notation +where we have uh cost + + align:start position:0% +where we have uh cost + + + align:start position:0% +where we have uh cost +minimizing the cost of achieving a unit + + align:start position:0% +minimizing the cost of achieving a unit + + + align:start position:0% +minimizing the cost of achieving a unit +output + + align:start position:0% +output + + + align:start position:0% +output +given the vector of factor prices w and + + align:start position:0% +given the vector of factor prices w and + + + align:start position:0% +given the vector of factor prices w and +we had the + + align:start position:0% +we had the + + + align:start position:0% +we had the +cost + + align:start position:0% +cost + + + align:start position:0% +cost +minimizing input values + + align:start position:0% +minimizing input values + + + align:start position:0% +minimizing input values +um and at the end of all that i finally + + align:start position:0% +um and at the end of all that i finally + + + align:start position:0% +um and at the end of all that i finally +got around to asking + + align:start position:0% +got around to asking + + + align:start position:0% +got around to asking +define what it means for the production + + align:start position:0% +define what it means for the production + + + align:start position:0% +define what it means for the production +of good one to be relatively + + align:start position:0% +of good one to be relatively + + + align:start position:0% +of good one to be relatively +more intensive in factor one + + align:start position:0% +more intensive in factor one + + + align:start position:0% +more intensive in factor one +than uh + + align:start position:0% +than uh + + + align:start position:0% +than uh +and the production of good two + + align:start position:0% +and the production of good two + + + align:start position:0% +and the production of good two +so + + align:start position:0% + + + + align:start position:0% + +let me + + align:start position:0% +let me + + + align:start position:0% +let me +see if we can get some how about a + + align:start position:0% +see if we can get some how about a + + + align:start position:0% +see if we can get some how about a +volunteer for that one + + align:start position:0% +volunteer for that one + + + align:start position:0% +volunteer for that one +no i can take this one + + align:start position:0% +no i can take this one + + + align:start position:0% +no i can take this one +um + + align:start position:0% +um + + + align:start position:0% +um +so + + align:start position:0% +so + + + align:start position:0% +so +the um + + align:start position:0% +the um + + + align:start position:0% +the um +this means that um like the + + align:start position:0% +this means that um like the + + + align:start position:0% +this means that um like the +per for producing a unit of good one + + align:start position:0% +per for producing a unit of good one + + + align:start position:0% +per for producing a unit of good one +versus a unit of good two + + align:start position:0% +versus a unit of good two + + + align:start position:0% +versus a unit of good two +you need like the ratio uh you need a + + align:start position:0% +you need like the ratio uh you need a + + + align:start position:0% +you need like the ratio uh you need a +the ratio of factor one to factor two + + align:start position:0% +the ratio of factor one to factor two + + + align:start position:0% +the ratio of factor one to factor two +that's used to produce one unit of good + + align:start position:0% +that's used to produce one unit of good + + + align:start position:0% +that's used to produce one unit of good +one is + + align:start position:0% +one is + + + align:start position:0% +one is +greater than the ratio of uh + + align:start position:0% +greater than the ratio of uh + + + align:start position:0% +greater than the ratio of uh +factor one to factor two when producing + + align:start position:0% +factor one to factor two when producing + + + align:start position:0% +factor one to factor two when producing +a unit of good two + + align:start position:0% +a unit of good two + + + align:start position:0% +a unit of good two +excellent + + align:start position:0% +excellent + + + align:start position:0% +excellent +perfect answer + + align:start position:0% +perfect answer + + + align:start position:0% +perfect answer +and then implicit let me just add a + + align:start position:0% +and then implicit let me just add a + + + align:start position:0% +and then implicit let me just add a +little bit editorial + + align:start position:0% +little bit editorial + + + align:start position:0% +little bit editorial +which is + + align:start position:0% +which is + + + align:start position:0% +which is +it's defined over the whole domain so + + align:start position:0% +it's defined over the whole domain so + + + align:start position:0% +it's defined over the whole domain so +whatever those factor prices are + + align:start position:0% +whatever those factor prices are + + + align:start position:0% +whatever those factor prices are +w1 and w2 it remains true + + align:start position:0% +w1 and w2 it remains true + + + align:start position:0% +w1 and w2 it remains true +that good one uses relatively more + + align:start position:0% +that good one uses relatively more + + + align:start position:0% +that good one uses relatively more +factor one than factor two and vice + + align:start position:0% +factor one than factor two and vice + + + align:start position:0% +factor one than factor two and vice +versa + + align:start position:0% +versa + + + align:start position:0% +versa +so it's a statement about the whole ring + + align:start position:0% +so it's a statement about the whole ring + + + align:start position:0% +so it's a statement about the whole ring +and we used + + align:start position:0% +and we used + + + align:start position:0% +and we used +that in the analysis in class when we + + align:start position:0% +that in the analysis in class when we + + + align:start position:0% +that in the analysis in class when we +were looking at the cost curves and what + + align:start position:0% +were looking at the cost curves and what + + + align:start position:0% +were looking at the cost curves and what +would happen if + + align:start position:0% +would happen if + + + align:start position:0% +would happen if +if input prices + + align:start position:0% +if input prices + + + align:start position:0% +if input prices +moved + + align:start position:0% +moved + + + align:start position:0% +moved +uh + + align:start position:0% + + + + align:start position:0% + +can someone take a stab at the + + align:start position:0% +can someone take a stab at the + + + align:start position:0% +can someone take a stab at the +stopler samuelson theorem for the + + align:start position:0% +stopler samuelson theorem for the + + + align:start position:0% +stopler samuelson theorem for the +determination of input prices + + align:start position:0% +determination of input prices + + + align:start position:0% +determination of input prices +as output prices change + + align:start position:0% + + + + align:start position:0% + +i can + + align:start position:0% +i can + + + align:start position:0% +i can +okay in the + + align:start position:0% +okay in the + + + align:start position:0% +okay in the +yeah in this theory + + align:start position:0% +yeah in this theory + + + align:start position:0% +yeah in this theory +that if the if if we assume that the + + align:start position:0% +that if the if if we assume that the + + + align:start position:0% +that if the if if we assume that the +model was to multiply two + + align:start position:0% +model was to multiply two + + + align:start position:0% +model was to multiply two +then + + align:start position:0% +then + + + align:start position:0% +then +when the output price like the price of + + align:start position:0% +when the output price like the price of + + + align:start position:0% +when the output price like the price of +good one increases than the + + align:start position:0% +good one increases than the + + + align:start position:0% +good one increases than the +intensive factors in producing the + + align:start position:0% +intensive factors in producing the + + + align:start position:0% +intensive factors in producing the +good one world also increases + + align:start position:0% +good one world also increases + + + align:start position:0% +good one world also increases +and the another factor that factored to + + align:start position:0% +and the another factor that factored to + + + align:start position:0% +and the another factor that factored to +and that was not the intensive factor + + align:start position:0% +and that was not the intensive factor + + + align:start position:0% +and that was not the intensive factor +the price of this factor world goes down + + align:start position:0% +the price of this factor world goes down + + + align:start position:0% +the price of this factor world goes down +yeah okay that's good yep + + align:start position:0% +yeah okay that's good yep + + + align:start position:0% +yeah okay that's good yep +so normally it's not a statement about + + align:start position:0% +so normally it's not a statement about + + + align:start position:0% +so normally it's not a statement about +international trade although it is + + align:start position:0% +international trade although it is + + + align:start position:0% +international trade although it is +very useful in that context we're just + + align:start position:0% +very useful in that context we're just + + + align:start position:0% +very useful in that context we're just +basically + + align:start position:0% +basically + + + align:start position:0% +basically +doing some comparative static exercises + + align:start position:0% +doing some comparative static exercises + + + align:start position:0% +doing some comparative static exercises +of what would happen if + + align:start position:0% +of what would happen if + + + align:start position:0% +of what would happen if +these exogenously given output prices + + align:start position:0% +these exogenously given output prices + + + align:start position:0% +these exogenously given output prices +are changing what's going to happen to + + align:start position:0% +are changing what's going to happen to + + + align:start position:0% +are changing what's going to happen to +input prices + + align:start position:0% + + + + align:start position:0% + +and then we + + align:start position:0% +and then we + + + align:start position:0% +and then we +we did a graph we used those cost curves + + align:start position:0% +we did a graph we used those cost curves + + + align:start position:0% +we did a graph we used those cost curves +to illustrate it + + align:start position:0% +to illustrate it + + + align:start position:0% +to illustrate it +i flagged the last question but i really + + align:start position:0% +i flagged the last question but i really + + + align:start position:0% +i flagged the last question but i really +don't want to ask that one i want to ask + + align:start position:0% +don't want to ask that one i want to ask + + + align:start position:0% +don't want to ask that one i want to ask +something + + align:start position:0% + + + + align:start position:0% + +a little harder to answer + + align:start position:0% + + + + align:start position:0% + +if we had two countries + + align:start position:0% +if we had two countries + + + align:start position:0% +if we had two countries +and each country had a representative + + align:start position:0% +and each country had a representative + + + align:start position:0% +and each country had a representative +consumer + + align:start position:0% +consumer + + + align:start position:0% +consumer +and there were two goods + + align:start position:0% +and there were two goods + + + align:start position:0% +and there were two goods +each of which can be produced in both + + align:start position:0% +each of which can be produced in both + + + align:start position:0% +each of which can be produced in both +countries + + align:start position:0% +countries + + + align:start position:0% +countries +and there are two factors that can be + + align:start position:0% +and there are two factors that can be + + + align:start position:0% +and there are two factors that can be +used in each good in each country + + align:start position:0% +used in each good in each country + + + align:start position:0% +used in each good in each country +we've got a lot of + + align:start position:0% +we've got a lot of + + + align:start position:0% +we've got a lot of +equations and unknowns we've got + + align:start position:0% +equations and unknowns we've got + + + align:start position:0% +equations and unknowns we've got +the consumer's consumption levels of the + + align:start position:0% +the consumer's consumption levels of the + + + align:start position:0% +the consumer's consumption levels of the +two goods + + align:start position:0% +two goods + + + align:start position:0% +two goods +the input being used to produce outputs + + align:start position:0% +the input being used to produce outputs + + + align:start position:0% +the input being used to produce outputs +of the two goods + + align:start position:0% +of the two goods + + + align:start position:0% +of the two goods +the outputs themselves of the two goods + + align:start position:0% +the outputs themselves of the two goods + + + align:start position:0% +the outputs themselves of the two goods +and the + + align:start position:0% +and the + + + align:start position:0% +and the +prices of each of the two inputs + + align:start position:0% +prices of each of the two inputs + + + align:start position:0% +prices of each of the two inputs +in both countries etc etc + + align:start position:0% +in both countries etc etc + + + align:start position:0% +in both countries etc etc +do you remember can someone tell me how + + align:start position:0% +do you remember can someone tell me how + + + align:start position:0% +do you remember can someone tell me how +we attack this problem in class + + align:start position:0% +we attack this problem in class + + + align:start position:0% +we attack this problem in class +in the sense of an algorithm + + align:start position:0% +in the sense of an algorithm + + + align:start position:0% +in the sense of an algorithm +that you know we broke it into pieces + + align:start position:0% + + + + align:start position:0% + +otherwise it's a very + + align:start position:0% +otherwise it's a very + + + align:start position:0% +otherwise it's a very +high dimensional problem + + align:start position:0% + + + + align:start position:0% + +if you remember the ordering yeah go + + align:start position:0% +if you remember the ordering yeah go + + + align:start position:0% +if you remember the ordering yeah go +ahead please + + align:start position:0% +ahead please + + + align:start position:0% +ahead please +yeah i think that the the way that we + + align:start position:0% +yeah i think that the the way that we + + + align:start position:0% +yeah i think that the the way that we +did this was kind of like um + + align:start position:0% +did this was kind of like um + + + align:start position:0% +did this was kind of like um +inductively where i i think that the way + + align:start position:0% +inductively where i i think that the way + + + align:start position:0% +inductively where i i think that the way +that we did this was first like pretend + + align:start position:0% +that we did this was first like pretend + + + align:start position:0% +that we did this was first like pretend +that + + align:start position:0% +that + + + align:start position:0% +that +uh pretend basically that it's just like + + align:start position:0% +uh pretend basically that it's just like + + + align:start position:0% +uh pretend basically that it's just like +the original two by two model and then + + align:start position:0% +the original two by two model and then + + + align:start position:0% +the original two by two model and then +we kind of solve for the what's supposed + + align:start position:0% +we kind of solve for the what's supposed + + + align:start position:0% +we kind of solve for the what's supposed +to happen there and then we build in the + + align:start position:0% +to happen there and then we build in the + + + align:start position:0% +to happen there and then we build in the +like additional thing of i'm pretty sure + + align:start position:0% +like additional thing of i'm pretty sure + + + align:start position:0% +like additional thing of i'm pretty sure +we built in the + + align:start position:0% +we built in the + + + align:start position:0% +we built in the +the different endowments i think was the + + align:start position:0% +the different endowments i think was the + + + align:start position:0% +the different endowments i think was the +difference in the two by two by two + + align:start position:0% +difference in the two by two by two + + + align:start position:0% +difference in the two by two by two +versus the two by two the kind of we saw + + align:start position:0% +versus the two by two the kind of we saw + + + align:start position:0% +versus the two by two the kind of we saw +for the smaller model and then we build + + align:start position:0% +for the smaller model and then we build + + + align:start position:0% +for the smaller model and then we build +it upwards to the bigger one + + align:start position:0% +it upwards to the bigger one + + + align:start position:0% +it upwards to the bigger one +that's true + + align:start position:0% +that's true + + + align:start position:0% +that's true +and what in particular did we focus on + + align:start position:0% +and what in particular did we focus on + + + align:start position:0% +and what in particular did we focus on +first in the smaller model + + align:start position:0% +first in the smaller model + + + align:start position:0% +first in the smaller model +um + + align:start position:0% +um + + + align:start position:0% +um +i think uh the way that we did this was + + align:start position:0% +i think uh the way that we did this was + + + align:start position:0% +i think uh the way that we did this was +kind of the + + align:start position:0% + + + + align:start position:0% + +um + + align:start position:0% +um + + + align:start position:0% +um +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +i i don't think i remember this + + align:start position:0% +i i don't think i remember this + + + align:start position:0% +i i don't think i remember this +okay anyone else want to + + align:start position:0% +okay anyone else want to + + + align:start position:0% +okay anyone else want to +take an attempt at it this is a + + align:start position:0% +take an attempt at it this is a + + + align:start position:0% +take an attempt at it this is a +difficult question + + align:start position:0% + + + + align:start position:0% + +to pose and hard to answer because it + + align:start position:0% +to pose and hard to answer because it + + + align:start position:0% +to pose and hard to answer because it +has + + align:start position:0% +has + + + align:start position:0% +has +to do with putting the + + align:start position:0% +to do with putting the + + + align:start position:0% +to do with putting the +pieces of a lot of information in the + + align:start position:0% +pieces of a lot of information in the + + + align:start position:0% +pieces of a lot of information in the +lecture and and sort of + + align:start position:0% +lecture and and sort of + + + align:start position:0% +lecture and and sort of +taking a step backwards and thinking + + align:start position:0% +taking a step backwards and thinking + + + align:start position:0% +taking a step backwards and thinking +about it globally + + align:start position:0% + + + + align:start position:0% + +okay well it starts + + align:start position:0% +okay well it starts + + + align:start position:0% +okay well it starts +with this stolper samuelson theorem so + + align:start position:0% +with this stolper samuelson theorem so + + + align:start position:0% +with this stolper samuelson theorem so +at this point + + align:start position:0% +at this point + + + align:start position:0% +at this point +early on in the lecture we were taking + + align:start position:0% +early on in the lecture we were taking + + + align:start position:0% +early on in the lecture we were taking +the prices of the goods p1 and p2 as + + align:start position:0% +the prices of the goods p1 and p2 as + + + align:start position:0% +the prices of the goods p1 and p2 as +given + + align:start position:0% +given + + + align:start position:0% +given +we weren't trying to solve for that i + + align:start position:0% +we weren't trying to solve for that i + + + align:start position:0% +we weren't trying to solve for that i +had not yet introduced consumers either + + align:start position:0% +had not yet introduced consumers either + + + align:start position:0% +had not yet introduced consumers either +we didn't even + + align:start position:0% +we didn't even + + + align:start position:0% +we didn't even +attempt to solve for the quantities + + align:start position:0% +attempt to solve for the quantities + + + align:start position:0% +attempt to solve for the quantities +we merely wanted to find + + align:start position:0% +we merely wanted to find + + + align:start position:0% +we merely wanted to find +equilibrium factor prices + + align:start position:0% +equilibrium factor prices + + + align:start position:0% +equilibrium factor prices +so + + align:start position:0% +so + + + align:start position:0% +so +so we had + + align:start position:0% +so we had + + + align:start position:0% +so we had +for a given country you could think of + + align:start position:0% +for a given country you could think of + + + align:start position:0% +for a given country you could think of +it that way a given economy + + align:start position:0% +it that way a given economy + + + align:start position:0% +it that way a given economy +we had the + + align:start position:0% +we had the + + + align:start position:0% +we had the +minimized cost of producing one unit of + + align:start position:0% +minimized cost of producing one unit of + + + align:start position:0% +minimized cost of producing one unit of +good one + + align:start position:0% +good one + + + align:start position:0% +good one +the minimized cost of producing one good + + align:start position:0% +the minimized cost of producing one good + + + align:start position:0% +the minimized cost of producing one good +one unit of good two + + align:start position:0% +one unit of good two + + + align:start position:0% +one unit of good two +and um + + align:start position:0% +and um + + + align:start position:0% +and um +we know we know that and that's in the + + align:start position:0% +we know we know that and that's in the + + + align:start position:0% +we know we know that and that's in the +space of input prices w1 and w2 + + align:start position:0% +space of input prices w1 and w2 + + + align:start position:0% +space of input prices w1 and w2 +so we know we're looking for an + + align:start position:0% +so we know we're looking for an + + + align:start position:0% +so we know we're looking for an +equilibrium + + align:start position:0% + + + + align:start position:0% + +therefore the input prices should be the + + align:start position:0% +therefore the input prices should be the + + + align:start position:0% +therefore the input prices should be the +same regardless of whether it's + + align:start position:0% +same regardless of whether it's + + + align:start position:0% +same regardless of whether it's +good one or good two + + align:start position:0% +good one or good two + + + align:start position:0% +good one or good two +so we looked at where those curves + + align:start position:0% +so we looked at where those curves + + + align:start position:0% +so we looked at where those curves +crossed and that you know that's the + + align:start position:0% +crossed and that you know that's the + + + align:start position:0% +crossed and that you know that's the +only point in the diagram + + align:start position:0% +only point in the diagram + + + align:start position:0% +only point in the diagram +where we can both + + align:start position:0% +where we can both + + + align:start position:0% +where we can both +have common input prices + + align:start position:0% +have common input prices + + + align:start position:0% +have common input prices +of the two inputs and + + align:start position:0% +of the two inputs and + + + align:start position:0% +of the two inputs and +beyond those curves where the curves + + align:start position:0% +beyond those curves where the curves + + + align:start position:0% +beyond those curves where the curves +crossed + + align:start position:0% +crossed + + + align:start position:0% +crossed +so that was the very very first part + + align:start position:0% +so that was the very very first part + + + align:start position:0% +so that was the very very first part +and then + + align:start position:0% +and then + + + align:start position:0% +and then +we given those prices + + align:start position:0% +we given those prices + + + align:start position:0% +we given those prices +we moved to + + align:start position:0% +we moved to + + + align:start position:0% +we moved to +a different space + + align:start position:0% + + + + align:start position:0% + +which had isoquants + + align:start position:0% +which had isoquants + + + align:start position:0% +which had isoquants +so there we have + + align:start position:0% +so there we have + + + align:start position:0% +so there we have +the unit output + + align:start position:0% +the unit output + + + align:start position:0% +the unit output +or any output really + + align:start position:0% +or any output really + + + align:start position:0% +or any output really +described by an isoquant + + align:start position:0% +described by an isoquant + + + align:start position:0% +described by an isoquant +a different isoquant for different + + align:start position:0% +a different isoquant for different + + + align:start position:0% +a different isoquant for different +quantities and we had + + align:start position:0% +quantities and we had + + + align:start position:0% +quantities and we had +the + + align:start position:0% +the + + + align:start position:0% +the +inputs on the on the x-axis so there we + + align:start position:0% +inputs on the on the x-axis so there we + + + align:start position:0% +inputs on the on the x-axis so there we +solve for + + align:start position:0% +solve for + + + align:start position:0% +solve for +minimizing unit cost again + + align:start position:0% +minimizing unit cost again + + + align:start position:0% +minimizing unit cost again +but what's on the x and y axis + + align:start position:0% +but what's on the x and y axis + + + align:start position:0% +but what's on the x and y axis +would be the input quantities and we and + + align:start position:0% +would be the input quantities and we and + + + align:start position:0% +would be the input quantities and we and +and uh + + align:start position:0% + + + + align:start position:0% + +and we know that has to align with the + + align:start position:0% +and we know that has to align with the + + + align:start position:0% +and we know that has to align with the +factor prices we already solved for + + align:start position:0% +factor prices we already solved for + + + align:start position:0% +factor prices we already solved for +so there we + + align:start position:0% +so there we + + + align:start position:0% +so there we +we determine both + + align:start position:0% +we determine both + + + align:start position:0% +we determine both +the input quantities as well as the + + align:start position:0% +the input quantities as well as the + + + align:start position:0% +the input quantities as well as the +output quantities + + align:start position:0% +output quantities + + + align:start position:0% +output quantities +where both + + align:start position:0% + + + + align:start position:0% + +firm 1 and firm 2 could be in + + align:start position:0% +firm 1 and firm 2 could be in + + + align:start position:0% +firm 1 and firm 2 could be in +equilibrium + + align:start position:0% +equilibrium + + + align:start position:0% +equilibrium +and then finally at the very end of the + + align:start position:0% +and then finally at the very end of the + + + align:start position:0% +and then finally at the very end of the +lecture + + align:start position:0% +lecture + + + align:start position:0% +lecture +we zeroed out + + align:start position:0% +we zeroed out + + + align:start position:0% +we zeroed out +to consider + + align:start position:0% +to consider + + + align:start position:0% +to consider +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +two countries not just + + align:start position:0% +two countries not just + + + align:start position:0% +two countries not just +one each with a consumer + + align:start position:0% +one each with a consumer + + + align:start position:0% +one each with a consumer +and + + align:start position:0% +and + + + align:start position:0% +and +those countries could be in autarky or + + align:start position:0% +those countries could be in autarky or + + + align:start position:0% +those countries could be in autarky or +potentially trading with one another + + align:start position:0% + + + + align:start position:0% + +both both specifications would be + + align:start position:0% +both both specifications would be + + + align:start position:0% +both both specifications would be +legitimate general equilibrium + + align:start position:0% +legitimate general equilibrium + + + align:start position:0% +legitimate general equilibrium +environments both autarky each country + + align:start position:0% +environments both autarky each country + + + align:start position:0% +environments both autarky each country +separately is one and then + + align:start position:0% +separately is one and then + + + align:start position:0% +separately is one and then +with trade it's another except obviously + + align:start position:0% +with trade it's another except obviously + + + align:start position:0% +with trade it's another except obviously +with trade consumption and production do + + align:start position:0% +with trade consumption and production do + + + align:start position:0% +with trade consumption and production do +not have to be the same because the + + align:start position:0% +not have to be the same because the + + + align:start position:0% +not have to be the same because the +countries + + align:start position:0% +countries + + + align:start position:0% +countries +can export one thing and import another + + align:start position:0% +can export one thing and import another + + + align:start position:0% +can export one thing and import another +sorry that's a rather long winded + + align:start position:0% +sorry that's a rather long winded + + + align:start position:0% +sorry that's a rather long winded +summary but again it's uh + + align:start position:0% +summary but again it's uh + + + align:start position:0% +summary but again it's uh +not the easiest lecture maybe + + align:start position:0% +not the easiest lecture maybe + + + align:start position:0% +not the easiest lecture maybe +potentially the hardest lecture + + align:start position:0% +potentially the hardest lecture + + + align:start position:0% +potentially the hardest lecture +in the whole series of lectures so i + + align:start position:0% +in the whole series of lectures so i + + + align:start position:0% +in the whole series of lectures so i +thought i would + + align:start position:0% +thought i would + + + align:start position:0% +thought i would +take the time to elaborate a bit on what + + align:start position:0% +take the time to elaborate a bit on what + + + align:start position:0% +take the time to elaborate a bit on what +we were doing + + align:start position:0% +we were doing + + + align:start position:0% +we were doing +um okay + + align:start position:0% +um okay + + + align:start position:0% +um okay +so that's + + align:start position:0% +so that's + + + align:start position:0% +so that's +the review + + align:start position:0% +the review + + + align:start position:0% +the review +now we come to + + align:start position:0% +now we come to + + + align:start position:0% +now we come to +applying a very similar theory + + align:start position:0% +applying a very similar theory + + + align:start position:0% +applying a very similar theory +to actual data so this is real and + + align:start position:0% +to actual data so this is real and + + + align:start position:0% +to actual data so this is real and +financial flows in thailand and an + + align:start position:0% +financial flows in thailand and an + + + align:start position:0% +financial flows in thailand and an +outline we're going to talk about + + align:start position:0% +outline we're going to talk about + + + align:start position:0% +outline we're going to talk about +villages again but we're going to embed + + align:start position:0% +villages again but we're going to embed + + + align:start position:0% +villages again but we're going to embed +them in the local + + align:start position:0% +them in the local + + + align:start position:0% +them in the local +economy + + align:start position:0% +economy + + + align:start position:0% +economy +and also their relationship to the + + align:start position:0% +and also their relationship to the + + + align:start position:0% +and also their relationship to the +national economy where we view the + + align:start position:0% +national economy where we view the + + + align:start position:0% +national economy where we view the +financial accounts which you've seen + + align:start position:0% +financial accounts which you've seen + + + align:start position:0% +financial accounts which you've seen +once before when we did sort of the + + align:start position:0% +once before when we did sort of the + + + align:start position:0% +once before when we did sort of the +bitcoin part + + align:start position:0% +bitcoin part + + + align:start position:0% +bitcoin part +we'll review them here balance sheets + + align:start position:0% +we'll review them here balance sheets + + + align:start position:0% +we'll review them here balance sheets +income statement and cash flow then + + align:start position:0% +income statement and cash flow then + + + align:start position:0% +income statement and cash flow then +more general background on these village + + align:start position:0% +more general background on these village + + + align:start position:0% +more general background on these village +economies and heterogeneity within them + + align:start position:0% +economies and heterogeneity within them + + + align:start position:0% +economies and heterogeneity within them +then we'll take + + align:start position:0% +then we'll take + + + align:start position:0% +then we'll take +the village economy as a whole as an + + align:start position:0% +the village economy as a whole as an + + + align:start position:0% +the village economy as a whole as an +entire economy + + align:start position:0% +entire economy + + + align:start position:0% +entire economy +and kind of come up with gdp and + + align:start position:0% +and kind of come up with gdp and + + + align:start position:0% +and kind of come up with gdp and +village + + align:start position:0% +village + + + align:start position:0% +village +income the way we come up with national + + align:start position:0% +income the way we come up with national + + + align:start position:0% +income the way we come up with national +income and the national income and + + align:start position:0% +income and the national income and + + + align:start position:0% +income and the national income and +product accounts + + align:start position:0% +product accounts + + + align:start position:0% +product accounts +and then finally what as a small open + + align:start position:0% +and then finally what as a small open + + + align:start position:0% +and then finally what as a small open +economy + + align:start position:0% +economy + + + align:start position:0% +economy +we can look at flow of funds balance of + + align:start position:0% +we can look at flow of funds balance of + + + align:start position:0% +we can look at flow of funds balance of +payments how open or how closed is the + + align:start position:0% +payments how open or how closed is the + + + align:start position:0% +payments how open or how closed is the +economy + + align:start position:0% +economy + + + align:start position:0% +economy +and then we come to this calibration + + align:start position:0% +and then we come to this calibration + + + align:start position:0% +and then we come to this calibration +part which i already highlighted with + + align:start position:0% +part which i already highlighted with + + + align:start position:0% +part which i already highlighted with +respect to the other start reading + + align:start position:0% +respect to the other start reading + + + align:start position:0% +respect to the other start reading +dawkins at al what does it mean to be + + align:start position:0% +dawkins at al what does it mean to be + + + align:start position:0% +dawkins at al what does it mean to be +calibrating a model which they often did + + align:start position:0% +calibrating a model which they often did + + + align:start position:0% +calibrating a model which they often did +in the trade context as we do here + + align:start position:0% +in the trade context as we do here + + + align:start position:0% +in the trade context as we do here +and we'll look at model predicted data + + align:start position:0% +and we'll look at model predicted data + + + align:start position:0% +and we'll look at model predicted data +and compare directly to actual data + + align:start position:0% +and compare directly to actual data + + + align:start position:0% +and compare directly to actual data +and then look at some counter factuals + + align:start position:0% +and then look at some counter factuals + + + align:start position:0% +and then look at some counter factuals +like uh imposing tariffs and frictions + + align:start position:0% +like uh imposing tariffs and frictions + + + align:start position:0% +like uh imposing tariffs and frictions +so last time and today you could think + + align:start position:0% +so last time and today you could think + + + align:start position:0% +so last time and today you could think +of this question as + + align:start position:0% +of this question as + + + align:start position:0% +of this question as +free trade who are the winners and + + align:start position:0% +free trade who are the winners and + + + align:start position:0% +free trade who are the winners and +losers tariffs + + align:start position:0% +losers tariffs + + + align:start position:0% +losers tariffs +who are the winners and losers and not + + align:start position:0% +who are the winners and losers and not + + + align:start position:0% +who are the winners and losers and not +in the abstract as in last time but + + align:start position:0% +in the abstract as in last time but + + + align:start position:0% +in the abstract as in last time but +actually here in the context of a + + align:start position:0% +actually here in the context of a + + + align:start position:0% +actually here in the context of a +calibrated model you'll actually see the + + align:start position:0% +calibrated model you'll actually see the + + + align:start position:0% +calibrated model you'll actually see the +impact on individual people living in + + align:start position:0% +impact on individual people living in + + + align:start position:0% +impact on individual people living in +these villages + + align:start position:0% +these villages + + + align:start position:0% +these villages +and then when we get to the us we'll do + + align:start position:0% +and then when we get to the us we'll do + + + align:start position:0% +and then when we get to the us we'll do +it all again on thursday which is a + + align:start position:0% +it all again on thursday which is a + + + align:start position:0% +it all again on thursday which is a +different context but the same kind of + + align:start position:0% +different context but the same kind of + + + align:start position:0% +different context but the same kind of +theory okay + + align:start position:0% +theory okay + + + align:start position:0% +theory okay +so you've seen this before let me + + align:start position:0% +so you've seen this before let me + + + align:start position:0% +so you've seen this before let me +highlight the thai map we have these two + + align:start position:0% +highlight the thai map we have these two + + + align:start position:0% +highlight the thai map we have these two +provinces cha chung sao and loperi in + + align:start position:0% +provinces cha chung sao and loperi in + + + align:start position:0% +provinces cha chung sao and loperi in +the central area of the country near if + + align:start position:0% +the central area of the country near if + + + align:start position:0% +the central area of the country near if +not right on top of bangkok and we have + + align:start position:0% +not right on top of bangkok and we have + + + align:start position:0% +not right on top of bangkok and we have +the other two bertram and sisiket + + align:start position:0% +the other two bertram and sisiket + + + align:start position:0% +the other two bertram and sisiket +in the northeast and much more agrarian + + align:start position:0% +in the northeast and much more agrarian + + + align:start position:0% +in the northeast and much more agrarian +area of the country this is sisa cat i + + align:start position:0% +area of the country this is sisa cat i + + + align:start position:0% +area of the country this is sisa cat i +muttered something about not finding + + align:start position:0% +muttered something about not finding + + + align:start position:0% +muttered something about not finding +these monthly starred villages but i + + align:start position:0% +these monthly starred villages but i + + + align:start position:0% +these monthly starred villages but i +knew where they were and now i realize + + align:start position:0% +knew where they were and now i realize + + + align:start position:0% +knew where they were and now i realize +it's still very hard to read but these + + align:start position:0% +it's still very hard to read but these + + + align:start position:0% +it's still very hard to read but these +sort of cheerio circles correspond to + + align:start position:0% +sort of cheerio circles correspond to + + + align:start position:0% +sort of cheerio circles correspond to +baseline survey done in 1997 a subset of + + align:start position:0% +baseline survey done in 1997 a subset of + + + align:start position:0% +baseline survey done in 1997 a subset of +those villages were chosen from 98 + + align:start position:0% +those villages were chosen from 98 + + + align:start position:0% +those villages were chosen from 98 +onward including the data that we're + + align:start position:0% +onward including the data that we're + + + align:start position:0% +onward including the data that we're +using + + align:start position:0% +using + + + align:start position:0% +using +in which case it's a monthly survey so + + align:start position:0% +in which case it's a monthly survey so + + + align:start position:0% +in which case it's a monthly survey so +so the cheerio covers up the star and + + align:start position:0% +so the cheerio covers up the star and + + + align:start position:0% +so the cheerio covers up the star and +produces these green like objects up + + align:start position:0% +produces these green like objects up + + + align:start position:0% +produces these green like objects up +here so that's the cluster so there are + + align:start position:0% +here so that's the cluster so there are + + + align:start position:0% +here so that's the cluster so there are +four villages in cesa cat that + + align:start position:0% +four villages in cesa cat that + + + align:start position:0% +four villages in cesa cat that +constitute the monthly data and likewise + + align:start position:0% +constitute the monthly data and likewise + + + align:start position:0% +constitute the monthly data and likewise +they're going to be four each in the + + align:start position:0% +they're going to be four each in the + + + align:start position:0% +they're going to be four each in the +other three provinces okay so let's + + align:start position:0% +other three provinces okay so let's + + + align:start position:0% +other three provinces okay so let's +take loperi over here + + align:start position:0% +take loperi over here + + + align:start position:0% +take loperi over here +and take a wage earner + + align:start position:0% +and take a wage earner + + + align:start position:0% +and take a wage earner +and look at + + align:start position:0% +and look at + + + align:start position:0% +and look at +this actual + + align:start position:0% +this actual + + + align:start position:0% +this actual +households + + align:start position:0% +households + + + align:start position:0% +households +income statement so you've seen version + + align:start position:0% +income statement so you've seen version + + + align:start position:0% +income statement so you've seen version +of this before and i remember asking you + + align:start position:0% +of this before and i remember asking you + + + align:start position:0% +of this before and i remember asking you +about it + + align:start position:0% +about it + + + align:start position:0% +about it +in the follow-up we've got revenues + + align:start position:0% +in the follow-up we've got revenues + + + align:start position:0% +in the follow-up we've got revenues +and costs in this case + + align:start position:0% +and costs in this case + + + align:start position:0% +and costs in this case +this guy does a little bit of livestock + + align:start position:0% +this guy does a little bit of livestock + + + align:start position:0% +this guy does a little bit of livestock +but mostly it's wage labor + + align:start position:0% +but mostly it's wage labor + + + align:start position:0% +but mostly it's wage labor +and + + align:start position:0% +and + + + align:start position:0% +and +in principle could have had interest + + align:start position:0% +in principle could have had interest + + + align:start position:0% +in principle could have had interest +income but didn't + + align:start position:0% +income but didn't + + + align:start position:0% +income but didn't +and on the cost side you know most of + + align:start position:0% +and on the cost side you know most of + + + align:start position:0% +and on the cost side you know most of +these costs are associated with + + align:start position:0% +these costs are associated with + + + align:start position:0% +these costs are associated with +livestock + + align:start position:0% +livestock + + + align:start position:0% +livestock +and in debt has actually has an interest + + align:start position:0% +and in debt has actually has an interest + + + align:start position:0% +and in debt has actually has an interest +expense + + align:start position:0% +expense + + + align:start position:0% +expense +and then does consumption and uh + + align:start position:0% +and then does consumption and uh + + + align:start position:0% +and then does consumption and uh +subtracts that's off of income and has + + align:start position:0% +subtracts that's off of income and has + + + align:start position:0% +subtracts that's off of income and has +some savings so that's the income + + align:start position:0% +some savings so that's the income + + + align:start position:0% +some savings so that's the income +statement of household a + + align:start position:0% +statement of household a + + + align:start position:0% +statement of household a +which we have these kinds of statements + + align:start position:0% +which we have these kinds of statements + + + align:start position:0% +which we have these kinds of statements +for you know roughly 800 households + + align:start position:0% +for you know roughly 800 households + + + align:start position:0% +for you know roughly 800 households +here's what happens over time that labor + + align:start position:0% +here's what happens over time that labor + + + align:start position:0% +here's what happens over time that labor +income which is the dominant source of + + align:start position:0% +income which is the dominant source of + + + align:start position:0% +income which is the dominant source of +income falls + + align:start position:0% +income falls + + + align:start position:0% +income falls +and then gradually increases back up + + align:start position:0% +and then gradually increases back up + + + align:start position:0% +and then gradually increases back up +again + + align:start position:0% +again + + + align:start position:0% +again +other components are largely zero + + align:start position:0% +other components are largely zero + + + align:start position:0% +other components are largely zero +although this they started a business + + align:start position:0% +although this they started a business + + + align:start position:0% +although this they started a business +right in the last year or two + + align:start position:0% +right in the last year or two + + + align:start position:0% +right in the last year or two +cultivation rises and then falls again + + align:start position:0% +cultivation rises and then falls again + + + align:start position:0% +cultivation rises and then falls again +so trying this that or the other but + + align:start position:0% +so trying this that or the other but + + + align:start position:0% +so trying this that or the other but +largely labor income + + align:start position:0% +largely labor income + + + align:start position:0% +largely labor income +this same household has a balance sheet + + align:start position:0% +this same household has a balance sheet + + + align:start position:0% +this same household has a balance sheet +which has + + align:start position:0% +which has + + + align:start position:0% +which has +liabilities on the right-hand side and + + align:start position:0% +liabilities on the right-hand side and + + + align:start position:0% +liabilities on the right-hand side and +assets on the left-hand side since those + + align:start position:0% +assets on the left-hand side since those + + + align:start position:0% +assets on the left-hand side since those +things don't balance hopefully + + align:start position:0% +things don't balance hopefully + + + align:start position:0% +things don't balance hopefully +liabilities are smaller than assets and + + align:start position:0% +liabilities are smaller than assets and + + + align:start position:0% +liabilities are smaller than assets and +the difference is net worth + + align:start position:0% +the difference is net worth + + + align:start position:0% +the difference is net worth +so we have + + align:start position:0% +so we have + + + align:start position:0% +so we have +liabilities in net worth on the right + + align:start position:0% +liabilities in net worth on the right + + + align:start position:0% +liabilities in net worth on the right +hand side and assets on the left + + align:start position:0% +hand side and assets on the left + + + align:start position:0% +hand side and assets on the left +assets consist of financial assets like + + align:start position:0% +assets consist of financial assets like + + + align:start position:0% +assets consist of financial assets like +cash and could have been deposits a + + align:start position:0% +cash and could have been deposits a + + + align:start position:0% +cash and could have been deposits a +little bit of deposits in banks + + align:start position:0% +little bit of deposits in banks + + + align:start position:0% +little bit of deposits in banks +and + + align:start position:0% +and + + + align:start position:0% +and +those are financial assets and then we + + align:start position:0% +those are financial assets and then we + + + align:start position:0% +those are financial assets and then we +have you know real assets like livestock + + align:start position:0% +have you know real assets like livestock + + + align:start position:0% +have you know real assets like livestock +and so on inventories and we have other + + align:start position:0% +and so on inventories and we have other + + + align:start position:0% +and so on inventories and we have other +fixed assets including household assets + + align:start position:0% +fixed assets including household assets + + + align:start position:0% +fixed assets including household assets +okay + + align:start position:0% +okay + + + align:start position:0% +okay +you're wondering where i'm going with + + align:start position:0% +you're wondering where i'm going with + + + align:start position:0% +you're wondering where i'm going with +this i'm deliberately highlighting + + align:start position:0% +this i'm deliberately highlighting + + + align:start position:0% +this i'm deliberately highlighting +things they're going to come up + + align:start position:0% +things they're going to come up + + + align:start position:0% +things they're going to come up +momentarily + + align:start position:0% +momentarily + + + align:start position:0% +momentarily +and again + + align:start position:0% +and again + + + align:start position:0% +and again +the balance sheet over time for this + + align:start position:0% +the balance sheet over time for this + + + align:start position:0% +the balance sheet over time for this +household + + align:start position:0% +household + + + align:start position:0% +household +you can see wealth is going + + align:start position:0% +you can see wealth is going + + + align:start position:0% +you can see wealth is going +up + + align:start position:0% +up + + + align:start position:0% +up +mostly because assets are going up + + align:start position:0% +mostly because assets are going up + + + align:start position:0% +mostly because assets are going up +but toward the end when the household + + align:start position:0% +but toward the end when the household + + + align:start position:0% +but toward the end when the household +started that business they borrowed + + align:start position:0% +started that business they borrowed + + + align:start position:0% +started that business they borrowed +liabilities went up and net worth + + align:start position:0% +liabilities went up and net worth + + + align:start position:0% +liabilities went up and net worth +actually went down + + align:start position:0% +actually went down + + + align:start position:0% +actually went down +but anyway this is over time + + align:start position:0% +but anyway this is over time + + + align:start position:0% +but anyway this is over time +finally we have the statement of cash + + align:start position:0% +finally we have the statement of cash + + + align:start position:0% +finally we have the statement of cash +flow which i highlighted when we talked + + align:start position:0% +flow which i highlighted when we talked + + + align:start position:0% +flow which i highlighted when we talked +about bitcoin + + align:start position:0% +about bitcoin + + + align:start position:0% +about bitcoin +we've got cash flow from production cash + + align:start position:0% +we've got cash flow from production cash + + + align:start position:0% +we've got cash flow from production cash +flow from financing investment and + + align:start position:0% +flow from financing investment and + + + align:start position:0% +flow from financing investment and +consumption + + align:start position:0% +consumption + + + align:start position:0% +consumption +and that produces a measure of cash flow + + align:start position:0% +and that produces a measure of cash flow + + + align:start position:0% +and that produces a measure of cash flow +from the flows which has to sync up with + + align:start position:0% +from the flows which has to sync up with + + + align:start position:0% +from the flows which has to sync up with +the change in the cash in the balance + + align:start position:0% +the change in the cash in the balance + + + align:start position:0% +the change in the cash in the balance +sheet + + align:start position:0% +sheet + + + align:start position:0% +sheet +which it does in these data so next i + + align:start position:0% +which it does in these data so next i + + + align:start position:0% +which it does in these data so next i +want to talk about diversity across the + + align:start position:0% +want to talk about diversity across the + + + align:start position:0% +want to talk about diversity across the +households + + align:start position:0% +households + + + align:start position:0% +households +especially for the ones who are actually + + align:start position:0% +especially for the ones who are actually + + + align:start position:0% +especially for the ones who are actually +firms who have decided to go into + + align:start position:0% +firms who have decided to go into + + + align:start position:0% +firms who have decided to go into +business the types of activities + + align:start position:0% +business the types of activities + + + align:start position:0% +business the types of activities +cultivation farming business like retail + + align:start position:0% +cultivation farming business like retail + + + align:start position:0% +cultivation farming business like retail +outlets trucking stuff around livestock + + align:start position:0% +outlets trucking stuff around livestock + + + align:start position:0% +outlets trucking stuff around livestock +fish and shrimp and this is like a cobb + + align:start position:0% +fish and shrimp and this is like a cobb + + + align:start position:0% +fish and shrimp and this is like a cobb +douglas production function written out + + align:start position:0% +douglas production function written out + + + align:start position:0% +douglas production function written out +in logs so delta k is the intensity of + + align:start position:0% +in logs so delta k is the intensity of + + + align:start position:0% +in logs so delta k is the intensity of +the capital good and delta l is the + + align:start position:0% +the capital good and delta l is the + + + align:start position:0% +the capital good and delta l is the +intensity of the labor good + + align:start position:0% +intensity of the labor good + + + align:start position:0% +intensity of the labor good +and what we want to see are those factor + + align:start position:0% +and what we want to see are those factor + + + align:start position:0% +and what we want to see are those factor +intensities so in fact if you look + + align:start position:0% +intensities so in fact if you look + + + align:start position:0% +intensities so in fact if you look +cultivation is labor intensive it will + + align:start position:0% +cultivation is labor intensive it will + + + align:start position:0% +cultivation is labor intensive it will +fit the definition we reviewed at the + + align:start position:0% +fit the definition we reviewed at the + + + align:start position:0% +fit the definition we reviewed at the +beginning of class + + align:start position:0% +beginning of class + + + align:start position:0% +beginning of class +uses relatively more labor than capital + + align:start position:0% +uses relatively more labor than capital + + + align:start position:0% +uses relatively more labor than capital +because of the coefficients delta l and + + align:start position:0% +because of the coefficients delta l and + + + align:start position:0% +because of the coefficients delta l and +delta k + + align:start position:0% +delta k + + + align:start position:0% +delta k +on the other extreme the fish and shrimp + + align:start position:0% +on the other extreme the fish and shrimp + + + align:start position:0% +on the other extreme the fish and shrimp +uses almost no labor at all and uses + + align:start position:0% +uses almost no labor at all and uses + + + align:start position:0% +uses almost no labor at all and uses +tons of capital + + align:start position:0% +tons of capital + + + align:start position:0% +tons of capital +so we've got capital and labor intensive + + align:start position:0% +so we've got capital and labor intensive + + + align:start position:0% +so we've got capital and labor intensive +activities + + align:start position:0% +activities + + + align:start position:0% +activities +we can try to + + align:start position:0% +we can try to + + + align:start position:0% +we can try to +make it simpler and talk about basically + + align:start position:0% +make it simpler and talk about basically + + + align:start position:0% +make it simpler and talk about basically +agricultural goods versus others called + + align:start position:0% +agricultural goods versus others called + + + align:start position:0% +agricultural goods versus others called +manufacturing really means + + align:start position:0% +manufacturing really means + + + align:start position:0% +manufacturing really means +non-agricultural + + align:start position:0% +non-agricultural + + + align:start position:0% +non-agricultural +okay the other thing sitting up here is + + align:start position:0% +okay the other thing sitting up here is + + + align:start position:0% +okay the other thing sitting up here is +this epsilon + + align:start position:0% +this epsilon + + + align:start position:0% +this epsilon +this is quote an error term but it + + align:start position:0% +this is quote an error term but it + + + align:start position:0% +this is quote an error term but it +actually contains + + align:start position:0% +actually contains + + + align:start position:0% +actually contains +not just noisy data but a measurement of + + align:start position:0% +not just noisy data but a measurement of + + + align:start position:0% +not just noisy data but a measurement of +talent + + align:start position:0% +talent + + + align:start position:0% +talent +so if we took the average for a + + align:start position:0% +so if we took the average for a + + + align:start position:0% +so if we took the average for a +particular household eye + + align:start position:0% +particular household eye + + + align:start position:0% +particular household eye +we took the average of these epsilons + + align:start position:0% +we took the average of these epsilons + + + align:start position:0% +we took the average of these epsilons +they don't have to average out to zero + + align:start position:0% +they don't have to average out to zero + + + align:start position:0% +they don't have to average out to zero +they average out to something that is + + align:start position:0% +they average out to something that is + + + align:start position:0% +they average out to something that is +common to the sector that household eye + + align:start position:0% +common to the sector that household eye + + + align:start position:0% +common to the sector that household eye +is engaged in a bar and some other + + align:start position:0% +is engaged in a bar and some other + + + align:start position:0% +is engaged in a bar and some other +household specific talent called z okay + + align:start position:0% +household specific talent called z okay + + + align:start position:0% +household specific talent called z okay +so there's a sector and household + + align:start position:0% +so there's a sector and household + + + align:start position:0% +so there's a sector and household +specific talent variable + + align:start position:0% +specific talent variable + + + align:start position:0% +specific talent variable +that's wrapped up into these epsilons + + align:start position:0% +that's wrapped up into these epsilons + + + align:start position:0% +that's wrapped up into these epsilons +obviously if you're talented the + + align:start position:0% +obviously if you're talented the + + + align:start position:0% +obviously if you're talented the +epsilons are going to tend to be high + + align:start position:0% +epsilons are going to tend to be high + + + align:start position:0% +epsilons are going to tend to be high +meaning output's going to be high + + align:start position:0% +meaning output's going to be high + + + align:start position:0% +meaning output's going to be high +even controlling for capital and labor + + align:start position:0% +even controlling for capital and labor + + + align:start position:0% +even controlling for capital and labor +so if you look across the sectors + + align:start position:0% +so if you look across the sectors + + + align:start position:0% +so if you look across the sectors +at quote sectoral productivity + + align:start position:0% +at quote sectoral productivity + + + align:start position:0% +at quote sectoral productivity +they're pretty similar + + align:start position:0% +they're pretty similar + + + align:start position:0% +they're pretty similar +the highest one here is livestock the + + align:start position:0% +the highest one here is livestock the + + + align:start position:0% +the highest one here is livestock the +lowest one is business + + align:start position:0% +lowest one is business + + + align:start position:0% +lowest one is business +now in terms of the household specific + + align:start position:0% +now in terms of the household specific + + + align:start position:0% +now in terms of the household specific +productivities there's a whole + + align:start position:0% +productivities there's a whole + + + align:start position:0% +productivities there's a whole +cross-sectional dispersion of these zis + + align:start position:0% +cross-sectional dispersion of these zis + + + align:start position:0% +cross-sectional dispersion of these zis +in each sector and so this sigma + + align:start position:0% +in each sector and so this sigma + + + align:start position:0% +in each sector and so this sigma +is a characterization of the + + align:start position:0% +is a characterization of the + + + align:start position:0% +is a characterization of the +a bit like a variance of the + + align:start position:0% +a bit like a variance of the + + + align:start position:0% +a bit like a variance of the +distribution the point being that + + align:start position:0% +distribution the point being that + + + align:start position:0% +distribution the point being that +each household has a particular z + + align:start position:0% +each household has a particular z + + + align:start position:0% +each household has a particular z +depending on the sector in which they + + align:start position:0% +depending on the sector in which they + + + align:start position:0% +depending on the sector in which they +reside and they could be very talented + + align:start position:0% +reside and they could be very talented + + + align:start position:0% +reside and they could be very talented +or not talented at all even though + + align:start position:0% +or not talented at all even though + + + align:start position:0% +or not talented at all even though +they're engaged in that activity + + align:start position:0% +they're engaged in that activity + + + align:start position:0% +they're engaged in that activity +and these are estimated in the data + + align:start position:0% +and these are estimated in the data + + + align:start position:0% +and these are estimated in the data +you're looking at the actual numbers the + + align:start position:0% +you're looking at the actual numbers the + + + align:start position:0% +you're looking at the actual numbers the +other aspect of heterogeneity here in + + align:start position:0% +other aspect of heterogeneity here in + + + align:start position:0% +other aspect of heterogeneity here in +addition to household talent + + align:start position:0% +addition to household talent + + + align:start position:0% +addition to household talent +would be their wealth + + align:start position:0% +would be their wealth + + + align:start position:0% +would be their wealth +or specifically their fixed assets + + align:start position:0% +or specifically their fixed assets + + + align:start position:0% +or specifically their fixed assets +that's why i emphasized that when we + + align:start position:0% +that's why i emphasized that when we + + + align:start position:0% +that's why i emphasized that when we +went through the balance sheet and you + + align:start position:0% +went through the balance sheet and you + + + align:start position:0% +went through the balance sheet and you +can see the cross-sectional distribution + + align:start position:0% +can see the cross-sectional distribution + + + align:start position:0% +can see the cross-sectional distribution +in loperi which is near bangkok versus + + align:start position:0% +in loperi which is near bangkok versus + + + align:start position:0% +in loperi which is near bangkok versus +the cross-sectional distribution in bury + + align:start position:0% +the cross-sectional distribution in bury + + + align:start position:0% +the cross-sectional distribution in bury +rum + + align:start position:0% +rum + + + align:start position:0% +rum +which + + align:start position:0% +which + + + align:start position:0% +which +has a lot more mass over here to the + + align:start position:0% +has a lot more mass over here to the + + + align:start position:0% +has a lot more mass over here to the +left + + align:start position:0% +left + + + align:start position:0% +left +meaning low assets so indeed in the data + + align:start position:0% +meaning low assets so indeed in the data + + + align:start position:0% +meaning low assets so indeed in the data +loperi near bangkok has higher average + + align:start position:0% +loperi near bangkok has higher average + + + align:start position:0% +loperi near bangkok has higher average +fixed assets than does bergeron out in + + align:start position:0% +fixed assets than does bergeron out in + + + align:start position:0% +fixed assets than does bergeron out in +the northeast + + align:start position:0% +the northeast + + + align:start position:0% +the northeast +but again + + align:start position:0% +but again + + + align:start position:0% +but again +it is a whole distribution so a given + + align:start position:0% +it is a whole distribution so a given + + + align:start position:0% +it is a whole distribution so a given +household could have a lot of have + + align:start position:0% +household could have a lot of have + + + align:start position:0% +household could have a lot of have +relatively little wealth or have a lot + + align:start position:0% +relatively little wealth or have a lot + + + align:start position:0% +relatively little wealth or have a lot +of wealth even in burriron this actually + + align:start position:0% +of wealth even in burriron this actually + + + align:start position:0% +of wealth even in burriron this actually +is consistent with the paulson townsend + + align:start position:0% +is consistent with the paulson townsend + + + align:start position:0% +is consistent with the paulson townsend +kharavanov paper + + align:start position:0% +kharavanov paper + + + align:start position:0% +kharavanov paper +which was an application of mechanism + + align:start position:0% +which was an application of mechanism + + + align:start position:0% +which was an application of mechanism +design where we talked about the talent + + align:start position:0% +design where we talked about the talent + + + align:start position:0% +design where we talked about the talent +of + + align:start position:0% +of + + + align:start position:0% +of +being a firm + + align:start position:0% +being a firm + + + align:start position:0% +being a firm +theta i think we had it there + + align:start position:0% +theta i think we had it there + + + align:start position:0% +theta i think we had it there +and also we talked about assets + + align:start position:0% +and also we talked about assets + + + align:start position:0% +and also we talked about assets +separately + + align:start position:0% +separately + + + align:start position:0% +separately +and indeed we talked about a limited + + align:start position:0% +and indeed we talked about a limited + + + align:start position:0% +and indeed we talked about a limited +liability constraint which is coming up + + align:start position:0% +liability constraint which is coming up + + + align:start position:0% +liability constraint which is coming up +so we have this cash thing which as i + + align:start position:0% +so we have this cash thing which as i + + + align:start position:0% +so we have this cash thing which as i +was saying from your previous lecture + + align:start position:0% +was saying from your previous lecture + + + align:start position:0% +was saying from your previous lecture +you know cash holdings don't behave very + + align:start position:0% +you know cash holdings don't behave very + + + align:start position:0% +you know cash holdings don't behave very +well so we just imposed what we see in + + align:start position:0% +well so we just imposed what we see in + + + align:start position:0% +well so we just imposed what we see in +the data that cash holdings that part of + + align:start position:0% +the data that cash holdings that part of + + + align:start position:0% +the data that cash holdings that part of +wealth that they're putting into cash is + + align:start position:0% +wealth that they're putting into cash is + + + align:start position:0% +wealth that they're putting into cash is +fixed it turns out that consumption is + + align:start position:0% +fixed it turns out that consumption is + + + align:start position:0% +fixed it turns out that consumption is +related to that we impose + + align:start position:0% +related to that we impose + + + align:start position:0% +related to that we impose +that consumption is equal to an + + align:start position:0% +that consumption is equal to an + + + align:start position:0% +that consumption is equal to an +intercept + + align:start position:0% +intercept + + + align:start position:0% +intercept +plus profits less that intercept + + align:start position:0% +plus profits less that intercept + + + align:start position:0% +plus profits less that intercept +and gamma here + + align:start position:0% +and gamma here + + + align:start position:0% +and gamma here +has to do with omega which is the + + align:start position:0% +has to do with omega which is the + + + align:start position:0% +has to do with omega which is the +fraction of savings i put into cash i + + align:start position:0% +fraction of savings i put into cash i + + + align:start position:0% +fraction of savings i put into cash i +didn't put the algebra in which i + + align:start position:0% +didn't put the algebra in which i + + + align:start position:0% +didn't put the algebra in which i +probably should have done except all i + + align:start position:0% +probably should have done except all i + + + align:start position:0% +probably should have done except all i +want to say from this is the cash part + + align:start position:0% +want to say from this is the cash part + + + align:start position:0% +want to say from this is the cash part +of savings is just fitted to the model + + align:start position:0% +of savings is just fitted to the model + + + align:start position:0% +of savings is just fitted to the model +it's not something we derive + + align:start position:0% +it's not something we derive + + + align:start position:0% +it's not something we derive +so now i want to go back to those + + align:start position:0% +so now i want to go back to those + + + align:start position:0% +so now i want to go back to those +accounts and + + align:start position:0% +accounts and + + + align:start position:0% +accounts and +show you where + + align:start position:0% +show you where + + + align:start position:0% +show you where +gross national product comes from + + align:start position:0% +gross national product comes from + + + align:start position:0% +gross national product comes from +except that in this case it's going to + + align:start position:0% +except that in this case it's going to + + + align:start position:0% +except that in this case it's going to +be village level product and income + + align:start position:0% +be village level product and income + + + align:start position:0% +be village level product and income +and then we'll go on to + + align:start position:0% +and then we'll go on to + + + align:start position:0% +and then we'll go on to +flow of funds the balance sheet + + align:start position:0% +flow of funds the balance sheet + + + align:start position:0% +flow of funds the balance sheet +balance of payments and so on so the top + + align:start position:0% +balance of payments and so on so the top + + + align:start position:0% +balance of payments and so on so the top +you've seen before + + align:start position:0% +you've seen before + + + align:start position:0% +you've seen before +that's just a statement of income + + align:start position:0% +that's just a statement of income + + + align:start position:0% +that's just a statement of income +revenues less costs but now we start + + align:start position:0% +revenues less costs but now we start + + + align:start position:0% +revenues less costs but now we start +subtracting things from both sides for + + align:start position:0% +subtracting things from both sides for + + + align:start position:0% +subtracting things from both sides for +example to get rid of capital gains + + align:start position:0% +example to get rid of capital gains + + + align:start position:0% +example to get rid of capital gains +capital losses and indemnity + + align:start position:0% +capital losses and indemnity + + + align:start position:0% +capital losses and indemnity +we subtract them off + + align:start position:0% +we subtract them off + + + align:start position:0% +we subtract them off +and then they appear with the opposite + + align:start position:0% +and then they appear with the opposite + + + align:start position:0% +and then they appear with the opposite +sign on the left hand side + + align:start position:0% +sign on the left hand side + + + align:start position:0% +sign on the left hand side +likewise we have expenses from + + align:start position:0% +likewise we have expenses from + + + align:start position:0% +likewise we have expenses from +production + + align:start position:0% +production + + + align:start position:0% +production +which we subtract off of both sides + + align:start position:0% +which we subtract off of both sides + + + align:start position:0% +which we subtract off of both sides +hence it disappears on the hand side and + + align:start position:0% +hence it disappears on the hand side and + + + align:start position:0% +hence it disappears on the hand side and +reappears on the right and it's + + align:start position:0% +reappears on the right and it's + + + align:start position:0% +reappears on the right and it's +subtracted + + align:start position:0% +subtracted + + + align:start position:0% +subtracted +so + + align:start position:0% +so + + + align:start position:0% +so +we end up with revenues less expenses in + + align:start position:0% +we end up with revenues less expenses in + + + align:start position:0% +we end up with revenues less expenses in +production + + align:start position:0% +production + + + align:start position:0% +production +which we call output and on the left + + align:start position:0% +which we call output and on the left + + + align:start position:0% +which we call output and on the left +hand side we have the disposition of + + align:start position:0% +hand side we have the disposition of + + + align:start position:0% +hand side we have the disposition of +output output is used to pay interest + + align:start position:0% +output output is used to pay interest + + + align:start position:0% +output output is used to pay interest +it's used to pay interest for capital + + align:start position:0% +it's used to pay interest for capital + + + align:start position:0% +it's used to pay interest for capital +normally you would see wages paid to + + align:start position:0% +normally you would see wages paid to + + + align:start position:0% +normally you would see wages paid to +labor over here + + align:start position:0% +labor over here + + + align:start position:0% +labor over here +i'll come back to that momentarily + + align:start position:0% +i'll come back to that momentarily + + + align:start position:0% +i'll come back to that momentarily +and the + + align:start position:0% +and the + + + align:start position:0% +and the +residual is profits + + align:start position:0% +residual is profits + + + align:start position:0% +residual is profits +so + + align:start position:0% +so + + + align:start position:0% +so +all output gets paid in the sense of + + align:start position:0% +all output gets paid in the sense of + + + align:start position:0% +all output gets paid in the sense of +paying hired factors or what's left over + + align:start position:0% +paying hired factors or what's left over + + + align:start position:0% +paying hired factors or what's left over +accruing to the business owner + + align:start position:0% +accruing to the business owner + + + align:start position:0% +accruing to the business owner +so this is a classic decomposition of + + align:start position:0% +so this is a classic decomposition of + + + align:start position:0% +so this is a classic decomposition of +the national income accounts + + align:start position:0% +the national income accounts + + + align:start position:0% +the national income accounts +from production or from inputs + + align:start position:0% +from production or from inputs + + + align:start position:0% +from production or from inputs +we're really interested in international + + align:start position:0% +we're really interested in international + + + align:start position:0% +we're really interested in international +trade so we're really interested in here + + align:start position:0% +trade so we're really interested in here + + + align:start position:0% +trade so we're really interested in here +in you know how much is labor getting + + align:start position:0% +in you know how much is labor getting + + + align:start position:0% +in you know how much is labor getting +paid how much of the interest being paid + + align:start position:0% +paid how much of the interest being paid + + + align:start position:0% +paid how much of the interest being paid +to capital and so on + + align:start position:0% +to capital and so on + + + align:start position:0% +to capital and so on +as a function of output just a bit like + + align:start position:0% +as a function of output just a bit like + + + align:start position:0% +as a function of output just a bit like +the two by two by two lecture so if + + align:start position:0% +the two by two by two lecture so if + + + align:start position:0% +the two by two by two lecture so if +we're looking at output remember there + + align:start position:0% +we're looking at output remember there + + + align:start position:0% +we're looking at output remember there +are four villages in each province that + + align:start position:0% +are four villages in each province that + + + align:start position:0% +are four villages in each province that +were selected for the monthly data + + align:start position:0% +were selected for the monthly data + + + align:start position:0% +were selected for the monthly data +here you can actually see output going + + align:start position:0% +here you can actually see output going + + + align:start position:0% +here you can actually see output going +down in chat chung sao + + align:start position:0% +down in chat chung sao + + + align:start position:0% +down in chat chung sao +wiggling but going down whereas in + + align:start position:0% +wiggling but going down whereas in + + + align:start position:0% +wiggling but going down whereas in +buriram output's going up um and these + + align:start position:0% +buriram output's going up um and these + + + align:start position:0% +buriram output's going up um and these +are the other two provinces + + align:start position:0% +are the other two provinces + + + align:start position:0% +are the other two provinces +so + + align:start position:0% +so + + + align:start position:0% +so +another point to make is that output is + + align:start position:0% +another point to make is that output is + + + align:start position:0% +another point to make is that output is +different across different villages even + + align:start position:0% +different across different villages even + + + align:start position:0% +different across different villages even +though they're nearby to one another and + + align:start position:0% +though they're nearby to one another and + + + align:start position:0% +though they're nearby to one another and +also you'll miss it if i don't point it + + align:start position:0% +also you'll miss it if i don't point it + + + align:start position:0% +also you'll miss it if i don't point it +out probably + + align:start position:0% +out probably + + + align:start position:0% +out probably +which is the scale in the northeast the + + align:start position:0% +which is the scale in the northeast the + + + align:start position:0% +which is the scale in the northeast the +maximum value is six and five + + align:start position:0% +maximum value is six and five + + + align:start position:0% +maximum value is six and five +whereas in the central the maximum is 15 + + align:start position:0% +whereas in the central the maximum is 15 + + + align:start position:0% +whereas in the central the maximum is 15 +and 12. so yeah place villages near + + align:start position:0% +and 12. so yeah place villages near + + + align:start position:0% +and 12. so yeah place villages near +bangkok have higher output than villages + + align:start position:0% +bangkok have higher output than villages + + + align:start position:0% +bangkok have higher output than villages +in the northeast but there remains + + align:start position:0% +in the northeast but there remains + + + align:start position:0% +in the northeast but there remains +heterogeneity across the villages and + + align:start position:0% +heterogeneity across the villages and + + + align:start position:0% +heterogeneity across the villages and +and you see the ups and downs + + align:start position:0% +and you see the ups and downs + + + align:start position:0% +and you see the ups and downs +the shrimp ponds got hit with a bad + + align:start position:0% +the shrimp ponds got hit with a bad + + + align:start position:0% +the shrimp ponds got hit with a bad +shock that we've talked about previously + + align:start position:0% +shock that we've talked about previously + + + align:start position:0% +shock that we've talked about previously +in the network lecture under risk + + align:start position:0% +in the network lecture under risk + + + align:start position:0% +in the network lecture under risk +sharing so that's part of the decline in + + align:start position:0% +sharing so that's part of the decline in + + + align:start position:0% +sharing so that's part of the decline in +output in in chattering south bury rom + + align:start position:0% +output in in chattering south bury rom + + + align:start position:0% +output in in chattering south bury rom +used to be a bunch of villages we put + + align:start position:0% +used to be a bunch of villages we put + + + align:start position:0% +used to be a bunch of villages we put +rain gauges out there + + align:start position:0% +rain gauges out there + + + align:start position:0% +rain gauges out there +to measure waterfall and so on and then + + align:start position:0% +to measure waterfall and so on and then + + + align:start position:0% +to measure waterfall and so on and then +it experienced sort of a boom + + align:start position:0% +it experienced sort of a boom + + + align:start position:0% +it experienced sort of a boom +and those villages were subsumed by the + + align:start position:0% +and those villages were subsumed by the + + + align:start position:0% +and those villages were subsumed by the +town and you can see that expansion + + align:start position:0% +town and you can see that expansion + + + align:start position:0% +town and you can see that expansion +pretty dramatically in this output + + align:start position:0% +pretty dramatically in this output + + + align:start position:0% +pretty dramatically in this output +diagram + + align:start position:0% +diagram + + + align:start position:0% +diagram +and as i was saying we can decompose + + align:start position:0% +and as i was saying we can decompose + + + align:start position:0% +and as i was saying we can decompose +output into who gets it + + align:start position:0% +output into who gets it + + + align:start position:0% +output into who gets it +and you can see here + + align:start position:0% +and you can see here + + + align:start position:0% +and you can see here +wages which is the darkest line + + align:start position:0% +wages which is the darkest line + + + align:start position:0% +wages which is the darkest line +you know is is the bigger part of the + + align:start position:0% +you know is is the bigger part of the + + + align:start position:0% +you know is is the bigger part of the +disposition of output in very ram and + + align:start position:0% +disposition of output in very ram and + + + align:start position:0% +disposition of output in very ram and +sisa cat + + align:start position:0% +sisa cat + + + align:start position:0% +sisa cat +wages are not as much + + align:start position:0% +wages are not as much + + + align:start position:0% +wages are not as much +they're not trivial + + align:start position:0% +they're not trivial + + + align:start position:0% +they're not trivial +in + + align:start position:0% +in + + + align:start position:0% +in +near bangkok + + align:start position:0% +near bangkok + + + align:start position:0% +near bangkok +chatringshow and loperi instead we have + + align:start position:0% +chatringshow and loperi instead we have + + + align:start position:0% +chatringshow and loperi instead we have +these two sectors the labor intensive + + align:start position:0% +these two sectors the labor intensive + + + align:start position:0% +these two sectors the labor intensive +agricultural sector and + + align:start position:0% +agricultural sector and + + + align:start position:0% +agricultural sector and +the capital intensive manufacturing + + align:start position:0% +the capital intensive manufacturing + + + align:start position:0% +the capital intensive manufacturing +sector + + align:start position:0% +sector + + + align:start position:0% +sector +as sometimes having profit shares + + align:start position:0% +as sometimes having profit shares + + + align:start position:0% +as sometimes having profit shares +which are higher than the wages + + align:start position:0% +which are higher than the wages + + + align:start position:0% +which are higher than the wages +now we come to the savings investment + + align:start position:0% +now we come to the savings investment + + + align:start position:0% +now we come to the savings investment +account we take the balance sheet at a + + align:start position:0% +account we take the balance sheet at a + + + align:start position:0% +account we take the balance sheet at a +point in time and we take the first + + align:start position:0% +point in time and we take the first + + + align:start position:0% +point in time and we take the first +difference so now we'll have the change + + align:start position:0% +difference so now we'll have the change + + + align:start position:0% +difference so now we'll have the change +in liabilities the change in net worth + + align:start position:0% +in liabilities the change in net worth + + + align:start position:0% +in liabilities the change in net worth +on the right + + align:start position:0% +on the right + + + align:start position:0% +on the right +change in financial and real physical + + align:start position:0% +change in financial and real physical + + + align:start position:0% +change in financial and real physical +assets on the left + + align:start position:0% +assets on the left + + + align:start position:0% +assets on the left +we now go through this thing about + + align:start position:0% +we now go through this thing about + + + align:start position:0% +we now go through this thing about +subtracting items on the left and the + + align:start position:0% +subtracting items on the left and the + + + align:start position:0% +subtracting items on the left and the +right-hand side we leave the change in + + align:start position:0% +right-hand side we leave the change in + + + align:start position:0% +right-hand side we leave the change in +net worth on the right-hand side + + align:start position:0% +net worth on the right-hand side + + + align:start position:0% +net worth on the right-hand side +and the disposition of that change into + + align:start position:0% +and the disposition of that change into + + + align:start position:0% +and the disposition of that change into +an increase in financial or real assets + + align:start position:0% +an increase in financial or real assets + + + align:start position:0% +an increase in financial or real assets +or a decrease in liabilities + + align:start position:0% +or a decrease in liabilities + + + align:start position:0% +or a decrease in liabilities +so we can kind of see they're managing + + align:start position:0% +so we can kind of see they're managing + + + align:start position:0% +so we can kind of see they're managing +their portfolio + + align:start position:0% +their portfolio + + + align:start position:0% +their portfolio +in an accounting sense as a function of + + align:start position:0% +in an accounting sense as a function of + + + align:start position:0% +in an accounting sense as a function of +you know what do they do with savings + + align:start position:0% +you know what do they do with savings + + + align:start position:0% +you know what do they do with savings +and likewise if savings are negative + + align:start position:0% +and likewise if savings are negative + + + align:start position:0% +and likewise if savings are negative +because you know they consume more than + + align:start position:0% +because you know they consume more than + + + align:start position:0% +because you know they consume more than +they earn + + align:start position:0% +they earn + + + align:start position:0% +they earn +then they have to draw that value out of + + align:start position:0% +then they have to draw that value out of + + + align:start position:0% +then they have to draw that value out of +something or borrow + + align:start position:0% +something or borrow + + + align:start position:0% +something or borrow +so this is the allocation of savings + + align:start position:0% +so this is the allocation of savings + + + align:start position:0% +so this is the allocation of savings +across the four provinces uh the darkest + + align:start position:0% +across the four provinces uh the darkest + + + align:start position:0% +across the four provinces uh the darkest +line here is savings which is largely + + align:start position:0% +line here is savings which is largely + + + align:start position:0% +line here is savings which is largely +going up although not entirely + + align:start position:0% +going up although not entirely + + + align:start position:0% +going up although not entirely +savings that's going down in chat + + align:start position:0% +savings that's going down in chat + + + align:start position:0% +savings that's going down in chat +transfer as you might have expected + + align:start position:0% +transfer as you might have expected + + + align:start position:0% +transfer as you might have expected +since they gotta finance those losses + + align:start position:0% +since they gotta finance those losses + + + align:start position:0% +since they gotta finance those losses +that declining output from somewhere + + align:start position:0% +that declining output from somewhere + + + align:start position:0% +that declining output from somewhere +they're preserving consumption by taking + + align:start position:0% +they're preserving consumption by taking + + + align:start position:0% +they're preserving consumption by taking +it out of savings likewise + + align:start position:0% +it out of savings likewise + + + align:start position:0% +it out of savings likewise +they can save into fixed assets + + align:start position:0% +they can save into fixed assets + + + align:start position:0% +they can save into fixed assets +save into financial assets the thing + + align:start position:0% +save into financial assets the thing + + + align:start position:0% +save into financial assets the thing +that tracks the best overall + + align:start position:0% +that tracks the best overall + + + align:start position:0% +that tracks the best overall +tracks dark savings overall the best + + align:start position:0% +tracks dark savings overall the best + + + align:start position:0% +tracks dark savings overall the best +is financial and you can see in most of + + align:start position:0% +is financial and you can see in most of + + + align:start position:0% +is financial and you can see in most of +these diagrams the black dotted lines + + align:start position:0% +these diagrams the black dotted lines + + + align:start position:0% +these diagrams the black dotted lines +are close to the solid black line + + align:start position:0% +are close to the solid black line + + + align:start position:0% +are close to the solid black line +so financial asset increase when savings + + align:start position:0% +so financial asset increase when savings + + + align:start position:0% +so financial asset increase when savings +is positive + + align:start position:0% +is positive + + + align:start position:0% +is positive +but these other real physical stuff as + + align:start position:0% +but these other real physical stuff as + + + align:start position:0% +but these other real physical stuff as +well as gifts play a role gifts are not + + align:start position:0% +well as gifts play a role gifts are not + + + align:start position:0% +well as gifts play a role gifts are not +trivial in these economies as you + + align:start position:0% +trivial in these economies as you + + + align:start position:0% +trivial in these economies as you +already know from thinking about + + align:start position:0% +already know from thinking about + + + align:start position:0% +already know from thinking about +insurance and so on so + + align:start position:0% +insurance and so on so + + + align:start position:0% +insurance and so on so +you know all these things add up + + align:start position:0% +you know all these things add up + + + align:start position:0% +you know all these things add up +gifts financial transfers inventory and + + align:start position:0% +gifts financial transfers inventory and + + + align:start position:0% +gifts financial transfers inventory and +so on add up to savings but you know + + align:start position:0% +so on add up to savings but you know + + + align:start position:0% +so on add up to savings but you know +gifts could be negative + + align:start position:0% +gifts could be negative + + + align:start position:0% +gifts could be negative +because they're not incoming but they're + + align:start position:0% +because they're not incoming but they're + + + align:start position:0% +because they're not incoming but they're +outgoing they're not saving it they're + + align:start position:0% +outgoing they're not saving it they're + + + align:start position:0% +outgoing they're not saving it they're +giving it away + + align:start position:0% +giving it away + + + align:start position:0% +giving it away +it's not always negative gifts are + + align:start position:0% +it's not always negative gifts are + + + align:start position:0% +it's not always negative gifts are +positive in some instances but in any + + align:start position:0% +positive in some instances but in any + + + align:start position:0% +positive in some instances but in any +event they're not a trivial order of + + align:start position:0% +event they're not a trivial order of + + + align:start position:0% +event they're not a trivial order of +magnitude + + align:start position:0% +magnitude + + + align:start position:0% +magnitude +and we will look at that subsequently + + align:start position:0% +and we will look at that subsequently + + + align:start position:0% +and we will look at that subsequently +again + + align:start position:0% +again + + + align:start position:0% +again +in terms of financial flows + + align:start position:0% +in terms of financial flows + + + align:start position:0% +in terms of financial flows +you've got something called the current + + align:start position:0% +you've got something called the current + + + align:start position:0% +you've got something called the current +account like for the us for example are + + align:start position:0% +account like for the us for example are + + + align:start position:0% +account like for the us for example are +they running a trade balance or are they + + align:start position:0% +they running a trade balance or are they + + + align:start position:0% +they running a trade balance or are they +earning money from abroad and likewise + + align:start position:0% +earning money from abroad and likewise + + + align:start position:0% +earning money from abroad and likewise +for these villages they export and + + align:start position:0% +for these villages they export and + + + align:start position:0% +for these villages they export and +import stuff we take the trade balance + + align:start position:0% +import stuff we take the trade balance + + + align:start position:0% +import stuff we take the trade balance +as the difference + + align:start position:0% +as the difference + + + align:start position:0% +as the difference +if positive exports exceed imports and + + align:start position:0% +if positive exports exceed imports and + + + align:start position:0% +if positive exports exceed imports and +likewise some member of the household is + + align:start position:0% +likewise some member of the household is + + + align:start position:0% +likewise some member of the household is +in bangkok and earning money and sending + + align:start position:0% +in bangkok and earning money and sending + + + align:start position:0% +in bangkok and earning money and sending +that money back home it's a gift that's + + align:start position:0% +that money back home it's a gift that's + + + align:start position:0% +that money back home it's a gift that's +a factor income earned abroad like in + + align:start position:0% +a factor income earned abroad like in + + + align:start position:0% +a factor income earned abroad like in +china people work in the philippines and + + align:start position:0% +china people work in the philippines and + + + align:start position:0% +china people work in the philippines and +send money back home so so this is + + align:start position:0% +send money back home so so this is + + + align:start position:0% +send money back home so so this is +called the current account now there are + + align:start position:0% +called the current account now there are + + + align:start position:0% +called the current account now there are +corresponding items + + align:start position:0% +corresponding items + + + align:start position:0% +corresponding items +offsetting items on the financial + + align:start position:0% +offsetting items on the financial + + + align:start position:0% +offsetting items on the financial +account basically + + align:start position:0% +account basically + + + align:start position:0% +account basically +if you're running a trade surplus you're + + align:start position:0% +if you're running a trade surplus you're + + + align:start position:0% +if you're running a trade surplus you're +acquiring claims on foreigners which + + align:start position:0% +acquiring claims on foreigners which + + + align:start position:0% +acquiring claims on foreigners which +could be by holding their currency + + align:start position:0% +could be by holding their currency + + + align:start position:0% +could be by holding their currency +holding their financial assets or + + align:start position:0% +holding their financial assets or + + + align:start position:0% +holding their financial assets or +holding their real assets and as we'll + + align:start position:0% +holding their real assets and as we'll + + + align:start position:0% +holding their real assets and as we'll +talk about next time + + align:start position:0% +talk about next time + + + align:start position:0% +talk about next time +the us has been running a trade deficit + + align:start position:0% +the us has been running a trade deficit + + + align:start position:0% +the us has been running a trade deficit +with china which means china is + + align:start position:0% +with china which means china is + + + align:start position:0% +with china which means china is +acquiring claims on the u.s holding u.s + + align:start position:0% +acquiring claims on the u.s holding u.s + + + align:start position:0% +acquiring claims on the u.s holding u.s +treasuries real estate and so on + + align:start position:0% +treasuries real estate and so on + + + align:start position:0% +treasuries real estate and so on +so the names change to protect the + + align:start position:0% +so the names change to protect the + + + align:start position:0% +so the names change to protect the +innocent in the sense of we're not + + align:start position:0% +innocent in the sense of we're not + + + align:start position:0% +innocent in the sense of we're not +looking at countries here we're looking + + align:start position:0% +looking at countries here we're looking + + + align:start position:0% +looking at countries here we're looking +at villages but we're doing all the + + align:start position:0% +at villages but we're doing all the + + + align:start position:0% +at villages but we're doing all the +accounting for the villages the way is + + align:start position:0% +accounting for the villages the way is + + + align:start position:0% +accounting for the villages the way is +done for countries with exactly the same + + align:start position:0% +done for countries with exactly the same + + + align:start position:0% +done for countries with exactly the same +accounting identities + + align:start position:0% +accounting identities + + + align:start position:0% +accounting identities +and the point of all of this is only to + + align:start position:0% +and the point of all of this is only to + + + align:start position:0% +and the point of all of this is only to +tell you where some of these things that + + align:start position:0% +tell you where some of these things that + + + align:start position:0% +tell you where some of these things that +you've heard of are coming from from the + + align:start position:0% +you've heard of are coming from from the + + + align:start position:0% +you've heard of are coming from from the +ground up from each and every household + + align:start position:0% +ground up from each and every household + + + align:start position:0% +ground up from each and every household +we have the financial accounts income + + align:start position:0% +we have the financial accounts income + + + align:start position:0% +we have the financial accounts income +statement balance sheet and so on we can + + align:start position:0% +statement balance sheet and so on we can + + + align:start position:0% +statement balance sheet and so on we can +add it up over all households in the + + align:start position:0% +add it up over all households in the + + + align:start position:0% +add it up over all households in the +village + + align:start position:0% +village + + + align:start position:0% +village +as the sample allows + + align:start position:0% +as the sample allows + + + align:start position:0% +as the sample allows +and get the village level aggregates + + align:start position:0% +and get the village level aggregates + + + align:start position:0% +and get the village level aggregates +this is for all of thailand thailand was + + align:start position:0% +this is for all of thailand thailand was + + + align:start position:0% +this is for all of thailand thailand was +running a + + align:start position:0% +running a + + + align:start position:0% +running a +trade deficit and foreigners + + align:start position:0% +trade deficit and foreigners + + + align:start position:0% +trade deficit and foreigners +were acquiring claims on thailand until + + align:start position:0% +were acquiring claims on thailand until + + + align:start position:0% +were acquiring claims on thailand until +the 1997 financial crisis in which case + + align:start position:0% +the 1997 financial crisis in which case + + + align:start position:0% +the 1997 financial crisis in which case +things reversed and they've been a bit + + align:start position:0% +things reversed and they've been a bit + + + align:start position:0% +things reversed and they've been a bit +unstable ever since uh in this case + + align:start position:0% +unstable ever since uh in this case + + + align:start position:0% +unstable ever since uh in this case +balance of payments are roughly you know + + align:start position:0% +balance of payments are roughly you know + + + align:start position:0% +balance of payments are roughly you know +a certain percent of gdp + + align:start position:0% +a certain percent of gdp + + + align:start position:0% +a certain percent of gdp +maybe ten percent that's a big number + + align:start position:0% +maybe ten percent that's a big number + + + align:start position:0% +maybe ten percent that's a big number +typically five percent + + align:start position:0% +typically five percent + + + align:start position:0% +typically five percent +so when we come to villages you might + + align:start position:0% +so when we come to villages you might + + + align:start position:0% +so when we come to villages you might +ask how big are these flows + + align:start position:0% +ask how big are these flows + + + align:start position:0% +ask how big are these flows +and the answer is typically much bigger + + align:start position:0% +and the answer is typically much bigger + + + align:start position:0% +and the answer is typically much bigger +for example + + align:start position:0% +for example + + + align:start position:0% +for example +in cha chung sao the balance of payments + + align:start position:0% +in cha chung sao the balance of payments + + + align:start position:0% +in cha chung sao the balance of payments +including the trade and the current + + align:start position:0% +including the trade and the current + + + align:start position:0% +including the trade and the current +account you know can be as high as 20 + + align:start position:0% +account you know can be as high as 20 + + + align:start position:0% +account you know can be as high as 20 +percent of gdp + + align:start position:0% +percent of gdp + + + align:start position:0% +percent of gdp +and loperi likewise reaches 15 percent + + align:start position:0% +and loperi likewise reaches 15 percent + + + align:start position:0% +and loperi likewise reaches 15 percent +of gdp so they are small open economies + + align:start position:0% +of gdp so they are small open economies + + + align:start position:0% +of gdp so they are small open economies +these villages are engaged with the rest + + align:start position:0% +these villages are engaged with the rest + + + align:start position:0% +these villages are engaged with the rest +of the country and in fact we can break + + align:start position:0% +of the country and in fact we can break + + + align:start position:0% +of the country and in fact we can break +that down into + + align:start position:0% +that down into + + + align:start position:0% +that down into +the gifts which i showed you a moment + + align:start position:0% +the gifts which i showed you a moment + + + align:start position:0% +the gifts which i showed you a moment +ago as well as here + + align:start position:0% +ago as well as here + + + align:start position:0% +ago as well as here +the uh + + align:start position:0% +the uh + + + align:start position:0% +the uh +measure of openness in terms of trade + + align:start position:0% +measure of openness in terms of trade + + + align:start position:0% +measure of openness in terms of trade +which is exports minus imports so + + align:start position:0% +which is exports minus imports so + + + align:start position:0% +which is exports minus imports so +roughly toxin sound near bangkok + + align:start position:0% +roughly toxin sound near bangkok + + + align:start position:0% +roughly toxin sound near bangkok +is imports and exports are + + align:start position:0% +is imports and exports are + + + align:start position:0% +is imports and exports are +almost matching one another + + align:start position:0% +almost matching one another + + + align:start position:0% +almost matching one another +whereas out in the northeast the imports + + align:start position:0% +whereas out in the northeast the imports + + + align:start position:0% +whereas out in the northeast the imports +are a lot bigger than the exports + + align:start position:0% +are a lot bigger than the exports + + + align:start position:0% +are a lot bigger than the exports +there the imports are for production + + align:start position:0% +there the imports are for production + + + align:start position:0% +there the imports are for production +their inputs acquired for production and + + align:start position:0% +their inputs acquired for production and + + + align:start position:0% +their inputs acquired for production and +they export a little bit of their output + + align:start position:0% +they export a little bit of their output + + + align:start position:0% +they export a little bit of their output +they eat a lot of the rice that they + + align:start position:0% +they eat a lot of the rice that they + + + align:start position:0% +they eat a lot of the rice that they +produce + + align:start position:0% +produce + + + align:start position:0% +produce +and export less + + align:start position:0% +and export less + + + align:start position:0% +and export less +i'm getting ready to show you the model + + align:start position:0% +i'm getting ready to show you the model + + + align:start position:0% +i'm getting ready to show you the model +one + + align:start position:0% +one + + + align:start position:0% +one +what about the relative price at the + + align:start position:0% +what about the relative price at the + + + align:start position:0% +what about the relative price at the +beginning of this class we talked about + + align:start position:0% +beginning of this class we talked about + + + align:start position:0% +beginning of this class we talked about +price of good one the price of good two + + align:start position:0% +price of good one the price of good two + + + align:start position:0% +price of good one the price of good two +we have two sectors for simplicity + + align:start position:0% +we have two sectors for simplicity + + + align:start position:0% +we have two sectors for simplicity +agriculture and manufacturing + + align:start position:0% +agriculture and manufacturing + + + align:start position:0% +agriculture and manufacturing +so from the data we can actually see + + align:start position:0% +so from the data we can actually see + + + align:start position:0% +so from the data we can actually see +overall + + align:start position:0% +overall + + + align:start position:0% +overall +that the price of the agricultural good + + align:start position:0% +that the price of the agricultural good + + + align:start position:0% +that the price of the agricultural good +is going up + + align:start position:0% +is going up + + + align:start position:0% +is going up +the ratio is going down + + align:start position:0% +the ratio is going down + + + align:start position:0% +the ratio is going down +from the standpoint of a typical village + + align:start position:0% +from the standpoint of a typical village + + + align:start position:0% +from the standpoint of a typical village +you know with the possibility of imports + + align:start position:0% +you know with the possibility of imports + + + align:start position:0% +you know with the possibility of imports +and exports + + align:start position:0% +and exports + + + align:start position:0% +and exports +just the way we had countries possibly + + align:start position:0% +just the way we had countries possibly + + + align:start position:0% +just the way we had countries possibly +exporting and importing to each other + + align:start position:0% +exporting and importing to each other + + + align:start position:0% +exporting and importing to each other +in terms of the factor prices remember + + align:start position:0% +in terms of the factor prices remember + + + align:start position:0% +in terms of the factor prices remember +the minimized cost curve well this is + + align:start position:0% +the minimized cost curve well this is + + + align:start position:0% +the minimized cost curve well this is +over time so we can see the wage rate + + align:start position:0% +over time so we can see the wage rate + + + align:start position:0% +over time so we can see the wage rate +and the interest rate both adjusted to + + align:start position:0% +and the interest rate both adjusted to + + + align:start position:0% +and the interest rate both adjusted to +be in units of consumption and surreal + + align:start position:0% +be in units of consumption and surreal + + + align:start position:0% +be in units of consumption and surreal +values as the numerator so in the + + align:start position:0% +values as the numerator so in the + + + align:start position:0% +values as the numerator so in the +areas near bangkok the blue and the red + + align:start position:0% +areas near bangkok the blue and the red + + + align:start position:0% +areas near bangkok the blue and the red +we can see that wages tend to be higher + + align:start position:0% +we can see that wages tend to be higher + + + align:start position:0% +we can see that wages tend to be higher +than they are in the northeast + + align:start position:0% +than they are in the northeast + + + align:start position:0% +than they are in the northeast +now near bangkok you would think this is + + align:start position:0% +now near bangkok you would think this is + + + align:start position:0% +now near bangkok you would think this is +relatively capital abundant because + + align:start position:0% +relatively capital abundant because + + + align:start position:0% +relatively capital abundant because +they're pretty industrialized and short + + align:start position:0% +they're pretty industrialized and short + + + align:start position:0% +they're pretty industrialized and short +of labor + + align:start position:0% +of labor + + + align:start position:0% +of labor +so indeed the relative price of labor to + + align:start position:0% +so indeed the relative price of labor to + + + align:start position:0% +so indeed the relative price of labor to +capital is higher + + align:start position:0% +capital is higher + + + align:start position:0% +capital is higher +in the areas near bangkok reflecting the + + align:start position:0% +in the areas near bangkok reflecting the + + + align:start position:0% +in the areas near bangkok reflecting the +capital abundance and the relative + + align:start position:0% +capital abundance and the relative + + + align:start position:0% +capital abundance and the relative +shortage of labor the reverse is true in + + align:start position:0% +shortage of labor the reverse is true in + + + align:start position:0% +shortage of labor the reverse is true in +the northeast + + align:start position:0% +the northeast + + + align:start position:0% +the northeast +and also we can look at the interest + + align:start position:0% +and also we can look at the interest + + + align:start position:0% +and also we can look at the interest +rate which is like the price of capital + + align:start position:0% +rate which is like the price of capital + + + align:start position:0% +rate which is like the price of capital +and again you can see + + align:start position:0% +and again you can see + + + align:start position:0% +and again you can see +that now the blue and the red are at the + + align:start position:0% +that now the blue and the red are at the + + + align:start position:0% +that now the blue and the red are at the +bottom + + align:start position:0% +bottom + + + align:start position:0% +bottom +because places near bangkok are capital + + align:start position:0% +because places near bangkok are capital + + + align:start position:0% +because places near bangkok are capital +abundant + + align:start position:0% +abundant + + + align:start position:0% +abundant +and so the interest rates tend to be low + + align:start position:0% +and so the interest rates tend to be low + + + align:start position:0% +and so the interest rates tend to be low +we did this experiment for the hectaro + + align:start position:0% +we did this experiment for the hectaro + + + align:start position:0% +we did this experiment for the hectaro +lean model like countries that are + + align:start position:0% +lean model like countries that are + + + align:start position:0% +lean model like countries that are +relatively abundant in a factor should + + align:start position:0% +relatively abundant in a factor should + + + align:start position:0% +relatively abundant in a factor should +be exporting the good which uses that + + align:start position:0% +be exporting the good which uses that + + + align:start position:0% +be exporting the good which uses that +factor relatively intensively so you + + align:start position:0% +factor relatively intensively so you + + + align:start position:0% +factor relatively intensively so you +could imagine you know that places near + + align:start position:0% +could imagine you know that places near + + + align:start position:0% +could imagine you know that places near +bangkok that are abundant in capital + + align:start position:0% +bangkok that are abundant in capital + + + align:start position:0% +bangkok that are abundant in capital +will have a tendency to export the + + align:start position:0% +will have a tendency to export the + + + align:start position:0% +will have a tendency to export the +manufactured good because that's the one + + align:start position:0% +manufactured good because that's the one + + + align:start position:0% +manufactured good because that's the one +that's intensive in capital + + align:start position:0% +that's intensive in capital + + + align:start position:0% +that's intensive in capital +what am i doing today + + align:start position:0% +what am i doing today + + + align:start position:0% +what am i doing today +i'm just getting the labels to be + + align:start position:0% +i'm just getting the labels to be + + + align:start position:0% +i'm just getting the labels to be +realistic in actual context from + + align:start position:0% +realistic in actual context from + + + align:start position:0% +realistic in actual context from +realistic relative to last time + + align:start position:0% +realistic relative to last time + + + align:start position:0% +realistic relative to last time +learn the theory first now we're + + align:start position:0% +learn the theory first now we're + + + align:start position:0% +learn the theory first now we're +applying it although with some + + align:start position:0% +applying it although with some + + + align:start position:0% +applying it although with some +modifications the other thing you can + + align:start position:0% +modifications the other thing you can + + + align:start position:0% +modifications the other thing you can +see here is the interest rates are + + align:start position:0% +see here is the interest rates are + + + align:start position:0% +see here is the interest rates are +converging they're getting really close + + align:start position:0% +converging they're getting really close + + + align:start position:0% +converging they're getting really close +to one another over time so + + align:start position:0% +to one another over time so + + + align:start position:0% +to one another over time so +one imagines that + + align:start position:0% +one imagines that + + + align:start position:0% +one imagines that +if they could x trade in inputs not just + + align:start position:0% +if they could x trade in inputs not just + + + align:start position:0% +if they could x trade in inputs not just +outputs it's pretty easy to do that with + + align:start position:0% +outputs it's pretty easy to do that with + + + align:start position:0% +outputs it's pretty easy to do that with +a capital input but + + align:start position:0% +a capital input but + + + align:start position:0% +a capital input but +the wage rates are not converging so + + align:start position:0% +the wage rates are not converging so + + + align:start position:0% +the wage rates are not converging so +that's also a hint that like the 2x2 + + align:start position:0% +that's also a hint that like the 2x2 + + + align:start position:0% +that's also a hint that like the 2x2 +model we're not going to allow labor to + + align:start position:0% +model we're not going to allow labor to + + + align:start position:0% +model we're not going to allow labor to +be + + align:start position:0% +be + + + align:start position:0% +be +moving across borders okay + + align:start position:0% +moving across borders okay + + + align:start position:0% +moving across borders okay +so + + align:start position:0% +so + + + align:start position:0% +so +i'm going to show you the ingredients + + align:start position:0% +i'm going to show you the ingredients + + + align:start position:0% +i'm going to show you the ingredients +for small open economy and then i'm + + align:start position:0% +for small open economy and then i'm + + + align:start position:0% +for small open economy and then i'm +gonna tell you what the difference is + + align:start position:0% +gonna tell you what the difference is + + + align:start position:0% +gonna tell you what the difference is +with the two by two by two that we did + + align:start position:0% +with the two by two by two that we did + + + align:start position:0% +with the two by two by two that we did +last time so + + align:start position:0% +last time so + + + align:start position:0% +last time so +it is two by two + + align:start position:0% +it is two by two + + + align:start position:0% +it is two by two +two goods two factors although it's uh + + align:start position:0% +two goods two factors although it's uh + + + align:start position:0% +two goods two factors although it's uh +you know a village relative to the rest + + align:start position:0% +you know a village relative to the rest + + + align:start position:0% +you know a village relative to the rest +of the country different from last time + + align:start position:0% +of the country different from last time + + + align:start position:0% +of the country different from last time +we're going to have financial frictions + + align:start position:0% +we're going to have financial frictions + + + align:start position:0% +we're going to have financial frictions +like those borrowing to + + align:start position:0% +like those borrowing to + + + align:start position:0% +like those borrowing to +wealth ratios + + align:start position:0% +wealth ratios + + + align:start position:0% +wealth ratios +there's a lot of agents in each village + + align:start position:0% +there's a lot of agents in each village + + + align:start position:0% +there's a lot of agents in each village +and they differ in their wealth and + + align:start position:0% +and they differ in their wealth and + + + align:start position:0% +and they differ in their wealth and +ability levels they can choose to be + + align:start position:0% +ability levels they can choose to be + + + align:start position:0% +ability levels they can choose to be +workers or they could become a firm and + + align:start position:0% +workers or they could become a firm and + + + align:start position:0% +workers or they could become a firm and +if they're an entrepreneur they could be + + align:start position:0% +if they're an entrepreneur they could be + + + align:start position:0% +if they're an entrepreneur they could be +in the manufacturing or agricultural + + align:start position:0% +in the manufacturing or agricultural + + + align:start position:0% +in the manufacturing or agricultural +sector + + align:start position:0% +sector + + + align:start position:0% +sector +so that's the two one of the two tools + + align:start position:0% +so that's the two one of the two tools + + + align:start position:0% +so that's the two one of the two tools +to + + align:start position:0% +to + + + align:start position:0% +to +goods agriculture and manufacturing + + align:start position:0% +goods agriculture and manufacturing + + + align:start position:0% +goods agriculture and manufacturing +to inputs capital and labor + + align:start position:0% +to inputs capital and labor + + + align:start position:0% +to inputs capital and labor +with the factor intensities different + + align:start position:0% +with the factor intensities different + + + align:start position:0% +with the factor intensities different +labor supplied is owned by + + align:start position:0% +labor supplied is owned by + + + align:start position:0% +labor supplied is owned by +households and supplied inelastically + + align:start position:0% +households and supplied inelastically + + + align:start position:0% +households and supplied inelastically +like it was last time + + align:start position:0% +like it was last time + + + align:start position:0% +like it was last time +they get this wage w + + align:start position:0% +they get this wage w + + + align:start position:0% +they get this wage w +wealth is owned by households + + align:start position:0% +wealth is owned by households + + + align:start position:0% +wealth is owned by households +and supplied at an interest rate but + + align:start position:0% +and supplied at an interest rate but + + + align:start position:0% +and supplied at an interest rate but +it's also changing over time + + align:start position:0% +it's also changing over time + + + align:start position:0% +it's also changing over time +unlike what we had last time we've got + + align:start position:0% +unlike what we had last time we've got + + + align:start position:0% +unlike what we had last time we've got +dynamics and a way to save money over + + align:start position:0% +dynamics and a way to save money over + + + align:start position:0% +dynamics and a way to save money over +time + + align:start position:0% +time + + + align:start position:0% +time +they can use their capital or they can + + align:start position:0% +they can use their capital or they can + + + align:start position:0% +they can use their capital or they can +lend it out so we have a borrowing and + + align:start position:0% +lend it out so we have a borrowing and + + + align:start position:0% +lend it out so we have a borrowing and +lending market + + align:start position:0% +lending market + + + align:start position:0% +lending market +but that capital market is imperfect + + align:start position:0% +but that capital market is imperfect + + + align:start position:0% +but that capital market is imperfect +namely you can't necessarily use an + + align:start position:0% +namely you can't necessarily use an + + + align:start position:0% +namely you can't necessarily use an +unlimited amount of capital k + + align:start position:0% +unlimited amount of capital k + + + align:start position:0% +unlimited amount of capital k +you're bounded by your wealth + + align:start position:0% +you're bounded by your wealth + + + align:start position:0% +you're bounded by your wealth +so that for the third time today + + align:start position:0% +so that for the third time today + + + align:start position:0% +so that for the third time today +is mention of the limited liability + + align:start position:0% +is mention of the limited liability + + + align:start position:0% +is mention of the limited liability +constraints + + align:start position:0% +constraints + + + align:start position:0% +constraints +so + + align:start position:0% +so + + + align:start position:0% +so +differences with last time we have + + align:start position:0% +differences with last time we have + + + align:start position:0% +differences with last time we have +decreasing returns to scale + + align:start position:0% +decreasing returns to scale + + + align:start position:0% +decreasing returns to scale +whereas last time in the theory lecture + + align:start position:0% +whereas last time in the theory lecture + + + align:start position:0% +whereas last time in the theory lecture +we used and abused the fact that it was + + align:start position:0% +we used and abused the fact that it was + + + align:start position:0% +we used and abused the fact that it was +constant returns to scale + + align:start position:0% +constant returns to scale + + + align:start position:0% +constant returns to scale +hence unit cost of production which + + align:start position:0% +hence unit cost of production which + + + align:start position:0% +hence unit cost of production which +scale up and down depending on the level + + align:start position:0% +scale up and down depending on the level + + + align:start position:0% +scale up and down depending on the level +of production + + align:start position:0% +of production + + + align:start position:0% +of production +factor mobility is somewhat limited here + + align:start position:0% +factor mobility is somewhat limited here + + + align:start position:0% +factor mobility is somewhat limited here +but the capital good moves around unlike + + align:start position:0% +but the capital good moves around unlike + + + align:start position:0% +but the capital good moves around unlike +last time we have financial variables + + align:start position:0% +last time we have financial variables + + + align:start position:0% +last time we have financial variables +here and real variables + + align:start position:0% +here and real variables + + + align:start position:0% +here and real variables +whereas last time we only had real + + align:start position:0% +whereas last time we only had real + + + align:start position:0% +whereas last time we only had real +variables + + align:start position:0% +variables + + + align:start position:0% +variables +and likewise here we have borrowing + + align:start position:0% +and likewise here we have borrowing + + + align:start position:0% +and likewise here we have borrowing +constraints + + align:start position:0% +constraints + + + align:start position:0% +constraints +and last time we didn't have any of that + + align:start position:0% +and last time we didn't have any of that + + + align:start position:0% +and last time we didn't have any of that +but this model does have the different + + align:start position:0% +but this model does have the different + + + align:start position:0% +but this model does have the different +endowments of the factors + + align:start position:0% +endowments of the factors + + + align:start position:0% +endowments of the factors +it does have the different factor + + align:start position:0% +it does have the different factor + + + align:start position:0% +it does have the different factor +intensities + + align:start position:0% +intensities + + + align:start position:0% +intensities +it keeps the two by two by two well two + + align:start position:0% +it keeps the two by two by two well two + + + align:start position:0% +it keeps the two by two by two well two +by two anyway with small open economy + + align:start position:0% +by two anyway with small open economy + + + align:start position:0% +by two anyway with small open economy +and so + + align:start position:0% +and so + + + align:start position:0% +and so +part of what you're going to see in the + + align:start position:0% +part of what you're going to see in the + + + align:start position:0% +part of what you're going to see in the +simulations + + align:start position:0% +simulations + + + align:start position:0% +simulations +reflects what we learned last time + + align:start position:0% +reflects what we learned last time + + + align:start position:0% +reflects what we learned last time +and part of it is a bit different + + align:start position:0% +and part of it is a bit different + + + align:start position:0% +and part of it is a bit different +because it has + + align:start position:0% +because it has + + + align:start position:0% +because it has +a few additional realistic features + + align:start position:0% + + + + align:start position:0% + +rather than take you through + + align:start position:0% +rather than take you through + + + align:start position:0% +rather than take you through +the entire model i'll just give you the + + align:start position:0% +the entire model i'll just give you the + + + align:start position:0% +the entire model i'll just give you the +notation at the beginning + + align:start position:0% +notation at the beginning + + + align:start position:0% +notation at the beginning +there + + align:start position:0% +there + + + align:start position:0% +there +each entrepreneur can produce + + align:start position:0% +each entrepreneur can produce + + + align:start position:0% +each entrepreneur can produce +sector a which could be agriculture but + + align:start position:0% +sector a which could be agriculture but + + + align:start position:0% +sector a which could be agriculture but +it's also manufacturing a household has + + align:start position:0% +it's also manufacturing a household has + + + align:start position:0% +it's also manufacturing a household has +a certain talent level z + + align:start position:0% +a certain talent level z + + + align:start position:0% +a certain talent level z +and initial capital stock it will use + + align:start position:0% +and initial capital stock it will use + + + align:start position:0% +and initial capital stock it will use +its inputs + + align:start position:0% +its inputs + + + align:start position:0% +its inputs +capital and higher labor + + align:start position:0% +capital and higher labor + + + align:start position:0% +capital and higher labor +at its productivity level selling it for + + align:start position:0% +at its productivity level selling it for + + + align:start position:0% +at its productivity level selling it for +the price of output but it has to pay + + align:start position:0% +the price of output but it has to pay + + + align:start position:0% +the price of output but it has to pay +input costs for capital labor and the + + align:start position:0% +input costs for capital labor and the + + + align:start position:0% +input costs for capital labor and the +input prices are r and w + + align:start position:0% +input prices are r and w + + + align:start position:0% +input prices are r and w +so you've seen this many times + + align:start position:0% +so you've seen this many times + + + align:start position:0% +so you've seen this many times +this is just a statement of profits for + + align:start position:0% +this is just a statement of profits for + + + align:start position:0% +this is just a statement of profits for +a firm it happens to be a firm owned and + + align:start position:0% +a firm it happens to be a firm owned and + + + align:start position:0% +a firm it happens to be a firm owned and +entirely operated by a given household + + align:start position:0% +entirely operated by a given household + + + align:start position:0% +entirely operated by a given household +because the theta i j equals one and + + align:start position:0% +because the theta i j equals one and + + + align:start position:0% +because the theta i j equals one and +here's the borrowing constraint + + align:start position:0% +here's the borrowing constraint + + + align:start position:0% +here's the borrowing constraint +capital utilized is limited by the + + align:start position:0% +capital utilized is limited by the + + + align:start position:0% +capital utilized is limited by the +pre-existing stock of fixed assets but + + align:start position:0% +pre-existing stock of fixed assets but + + + align:start position:0% +pre-existing stock of fixed assets but +this constant c could be greater than + + align:start position:0% +this constant c could be greater than + + + align:start position:0% +this constant c could be greater than +one which allows them to borrow to + + align:start position:0% +one which allows them to borrow to + + + align:start position:0% +one which allows them to borrow to +borrow to acquire fixed assets and + + align:start position:0% +borrow to acquire fixed assets and + + + align:start position:0% +borrow to acquire fixed assets and +production + + align:start position:0% +production + + + align:start position:0% +production +greater than what they already own + + align:start position:0% +greater than what they already own + + + align:start position:0% +greater than what they already own +labor is non-negative + + align:start position:0% +labor is non-negative + + + align:start position:0% +labor is non-negative +as in that paper with anna paulsen and + + align:start position:0% +as in that paper with anna paulsen and + + + align:start position:0% +as in that paper with anna paulsen and +kuravanov they could choose to be a wage + + align:start position:0% +kuravanov they could choose to be a wage + + + align:start position:0% +kuravanov they could choose to be a wage +earner put all their wealth lend it out + + align:start position:0% +earner put all their wealth lend it out + + + align:start position:0% +earner put all their wealth lend it out +basically + + align:start position:0% +basically + + + align:start position:0% +basically +earn interest on it or they earn money + + align:start position:0% +earn interest on it or they earn money + + + align:start position:0% +earn interest on it or they earn money +from being a wage earner likewise we + + align:start position:0% +from being a wage earner likewise we + + + align:start position:0% +from being a wage earner likewise we +have profits for agriculturalists and + + align:start position:0% +have profits for agriculturalists and + + + align:start position:0% +have profits for agriculturalists and +manufacturers + + align:start position:0% +manufacturers + + + align:start position:0% +manufacturers +and they're + + align:start position:0% +and they're + + + align:start position:0% +and they're +in principle lending stuff out + + align:start position:0% +in principle lending stuff out + + + align:start position:0% +in principle lending stuff out +but they could be borrowing some of it + + align:start position:0% +but they could be borrowing some of it + + + align:start position:0% +but they could be borrowing some of it +back to finance production and then we + + align:start position:0% +back to finance production and then we + + + align:start position:0% +back to finance production and then we +have a utility over + + align:start position:0% +have a utility over + + + align:start position:0% +have a utility over +consumption of agriculture and + + align:start position:0% +consumption of agriculture and + + + align:start position:0% +consumption of agriculture and +manufactured goods + + align:start position:0% +manufactured goods + + + align:start position:0% +manufactured goods +which looks like kind of this cobb + + align:start position:0% +which looks like kind of this cobb + + + align:start position:0% +which looks like kind of this cobb +douglas thing + + align:start position:0% +douglas thing + + + align:start position:0% +douglas thing +where these ada's are cleverly chosen to + + align:start position:0% +where these ada's are cleverly chosen to + + + align:start position:0% +where these ada's are cleverly chosen to +allow us to talk about you know + + align:start position:0% +allow us to talk about you know + + + align:start position:0% +allow us to talk about you know +aggregate savings because in fact + + align:start position:0% +aggregate savings because in fact + + + align:start position:0% +aggregate savings because in fact +there's capital in manufacturing and + + align:start position:0% +there's capital in manufacturing and + + + align:start position:0% +there's capital in manufacturing and +capital in agriculture and we don't want + + align:start position:0% +capital in agriculture and we don't want + + + align:start position:0% +capital in agriculture and we don't want +to keep having to refer to the + + align:start position:0% +to keep having to refer to the + + + align:start position:0% +to keep having to refer to the +distinction about where they're saving + + align:start position:0% +distinction about where they're saving + + + align:start position:0% +distinction about where they're saving +so we come up with this ideal price + + align:start position:0% +so we come up with this ideal price + + + align:start position:0% +so we come up with this ideal price +index don't worry about it too much + + align:start position:0% +index don't worry about it too much + + + align:start position:0% +index don't worry about it too much +it exists that's all we need to know + + align:start position:0% +it exists that's all we need to know + + + align:start position:0% +it exists that's all we need to know +um okay + + align:start position:0% +um okay + + + align:start position:0% +um okay +it's a small open economy + + align:start position:0% +it's a small open economy + + + align:start position:0% +it's a small open economy +households have their capital endowment + + align:start position:0% +households have their capital endowment + + + align:start position:0% +households have their capital endowment +we fit a distribution that fits pretty + + align:start position:0% +we fit a distribution that fits pretty + + + align:start position:0% +we fit a distribution that fits pretty +well relative to the histograms i + + align:start position:0% +well relative to the histograms i + + + align:start position:0% +well relative to the histograms i +already shown you we have the labor + + align:start position:0% +already shown you we have the labor + + + align:start position:0% +already shown you we have the labor +endowments + + align:start position:0% +endowments + + + align:start position:0% +endowments +we help we know how much time they have + + align:start position:0% +we help we know how much time they have + + + align:start position:0% +we help we know how much time they have +we give them a little bit of sleep + + align:start position:0% +we give them a little bit of sleep + + + align:start position:0% +we give them a little bit of sleep +and come up with how many units of labor + + align:start position:0% +and come up with how many units of labor + + + align:start position:0% +and come up with how many units of labor +they can supply over the year which is a + + align:start position:0% +they can supply over the year which is a + + + align:start position:0% +they can supply over the year which is a +fixed and exogenous + + align:start position:0% +fixed and exogenous + + + align:start position:0% +fixed and exogenous +and they have a savings rate which again + + align:start position:0% +and they have a savings rate which again + + + align:start position:0% +and they have a savings rate which again +as i already said that was an omega + + align:start position:0% +as i already said that was an omega + + + align:start position:0% +as i already said that was an omega +we fit to kind of match the data i + + align:start position:0% +we fit to kind of match the data i + + + align:start position:0% +we fit to kind of match the data i +mentioned that in the context of the + + align:start position:0% +mentioned that in the context of the + + + align:start position:0% +mentioned that in the context of the +cash holdings + + align:start position:0% +cash holdings + + + align:start position:0% +cash holdings +one could imagine having these + + align:start position:0% +one could imagine having these + + + align:start position:0% +one could imagine having these +households solve discounted expected + + align:start position:0% +households solve discounted expected + + + align:start position:0% +households solve discounted expected +utility maximization problems over their + + align:start position:0% +utility maximization problems over their + + + align:start position:0% +utility maximization problems over their +lifetime + + align:start position:0% +lifetime + + + align:start position:0% +lifetime +that adds a lot to the complication so + + align:start position:0% +that adds a lot to the complication so + + + align:start position:0% +that adds a lot to the complication so +instead of doing that we just basically + + align:start position:0% +instead of doing that we just basically + + + align:start position:0% +instead of doing that we just basically +impose from the data on to the + + align:start position:0% +impose from the data on to the + + + align:start position:0% +impose from the data on to the +households + + align:start position:0% +households + + + align:start position:0% +households +an estimated savings rate now this is a + + align:start position:0% +an estimated savings rate now this is a + + + align:start position:0% +an estimated savings rate now this is a +kind of interesting diagram because + + align:start position:0% +kind of interesting diagram because + + + align:start position:0% +kind of interesting diagram because +all these parameters like the factor + + align:start position:0% +all these parameters like the factor + + + align:start position:0% +all these parameters like the factor +intensity numbers + + align:start position:0% +intensity numbers + + + align:start position:0% +intensity numbers +and everything else are are going to be + + align:start position:0% +and everything else are are going to be + + + align:start position:0% +and everything else are are going to be +calibrated + + align:start position:0% +calibrated + + + align:start position:0% +calibrated +which i'll tell you about momentarily + + align:start position:0% +which i'll tell you about momentarily + + + align:start position:0% +which i'll tell you about momentarily +and we will generate pictures + + align:start position:0% +and we will generate pictures + + + align:start position:0% +and we will generate pictures +like this so + + align:start position:0% +like this so + + + align:start position:0% +like this so +i mentioned the calibration only because + + align:start position:0% +i mentioned the calibration only because + + + align:start position:0% +i mentioned the calibration only because +you can draw any picture you want + + align:start position:0% +you can draw any picture you want + + + align:start position:0% +you can draw any picture you want +but this is what it's going to look like + + align:start position:0% +but this is what it's going to look like + + + align:start position:0% +but this is what it's going to look like +after the work is done of estimation + + align:start position:0% +after the work is done of estimation + + + align:start position:0% +after the work is done of estimation +over here we have low wealth households + + align:start position:0% +over here we have low wealth households + + + align:start position:0% +over here we have low wealth households +versus high wealth households + + align:start position:0% +versus high wealth households + + + align:start position:0% +versus high wealth households +the other dimension of heterogeneity is + + align:start position:0% +the other dimension of heterogeneity is + + + align:start position:0% +the other dimension of heterogeneity is +low talent + + align:start position:0% +low talent + + + align:start position:0% +low talent +versus high talent and you can see if + + align:start position:0% +versus high talent and you can see if + + + align:start position:0% +versus high talent and you can see if +they're not very talented they're not + + align:start position:0% +they're not very talented they're not + + + align:start position:0% +they're not very talented they're not +going to go into either type of business + + align:start position:0% +going to go into either type of business + + + align:start position:0% +going to go into either type of business +they're going to be workers + + align:start position:0% +they're going to be workers + + + align:start position:0% +they're going to be workers +on the other hand if talent reaches a + + align:start position:0% +on the other hand if talent reaches a + + + align:start position:0% +on the other hand if talent reaches a +higher level + + align:start position:0% +higher level + + + align:start position:0% +higher level +they could decide to go into + + align:start position:0% +they could decide to go into + + + align:start position:0% +they could decide to go into +manufacturing or agriculture + + align:start position:0% +manufacturing or agriculture + + + align:start position:0% +manufacturing or agriculture +and then for a given level of wealth + + align:start position:0% +and then for a given level of wealth + + + align:start position:0% +and then for a given level of wealth +they may be constrained or unconstrained + + align:start position:0% +they may be constrained or unconstrained + + + align:start position:0% +they may be constrained or unconstrained +ironically the more talented they are + + align:start position:0% +ironically the more talented they are + + + align:start position:0% +ironically the more talented they are +given a certain borrowing constraint and + + align:start position:0% +given a certain borrowing constraint and + + + align:start position:0% +given a certain borrowing constraint and +their wealth + + align:start position:0% +their wealth + + + align:start position:0% +their wealth +the more constrained they're going to be + + align:start position:0% +the more constrained they're going to be + + + align:start position:0% +the more constrained they're going to be +because they would like to do more and + + align:start position:0% +because they would like to do more and + + + align:start position:0% +because they would like to do more and +they're not allowed to do it + + align:start position:0% +they're not allowed to do it + + + align:start position:0% +they're not allowed to do it +and here + + align:start position:0% +and here + + + align:start position:0% +and here +it actually moves from being constrained + + align:start position:0% +it actually moves from being constrained + + + align:start position:0% +it actually moves from being constrained +in manufacturing + + align:start position:0% +in manufacturing + + + align:start position:0% +in manufacturing +to being constrained in agriculture + + align:start position:0% +to being constrained in agriculture + + + align:start position:0% +to being constrained in agriculture +so it's the really really talented guys + + align:start position:0% +so it's the really really talented guys + + + align:start position:0% +so it's the really really talented guys +who are sticking on the farm + + align:start position:0% +who are sticking on the farm + + + align:start position:0% +who are sticking on the farm +given the parameters that we estimated + + align:start position:0% +given the parameters that we estimated + + + align:start position:0% +given the parameters that we estimated +this i've already said we're going to + + align:start position:0% +this i've already said we're going to + + + align:start position:0% +this i've already said we're going to +have an open market for capital + + align:start position:0% +have an open market for capital + + + align:start position:0% +have an open market for capital +but a closed market for labor + + align:start position:0% +but a closed market for labor + + + align:start position:0% +but a closed market for labor +then again that's because the interest + + align:start position:0% +then again that's because the interest + + + align:start position:0% +then again that's because the interest +rates are converging so it looks like in + + align:start position:0% +rates are converging so it looks like in + + + align:start position:0% +rates are converging so it looks like in +the end at least capital can + + align:start position:0% +the end at least capital can + + + align:start position:0% +the end at least capital can +be moved across provinces without a cost + + align:start position:0% +be moved across provinces without a cost + + + align:start position:0% +be moved across provinces without a cost +here's finally the calibration slide + + align:start position:0% +here's finally the calibration slide + + + align:start position:0% +here's finally the calibration slide +we have to figure out the relative + + align:start position:0% +we have to figure out the relative + + + align:start position:0% +we have to figure out the relative +prices we need the interest rate + + align:start position:0% +prices we need the interest rate + + + align:start position:0% +prices we need the interest rate +we're going to take it as exogenous + + align:start position:0% +we're going to take it as exogenous + + + align:start position:0% +we're going to take it as exogenous +the relative price of manufacturing + + align:start position:0% +the relative price of manufacturing + + + align:start position:0% +the relative price of manufacturing +versus agriculture + + align:start position:0% +versus agriculture + + + align:start position:0% +versus agriculture +we're going to take as exogenous and + + align:start position:0% +we're going to take as exogenous and + + + align:start position:0% +we're going to take as exogenous and +match it up with what we see + + align:start position:0% +match it up with what we see + + + align:start position:0% +match it up with what we see +in the data + + align:start position:0% +in the data + + + align:start position:0% +in the data +as exogenous i'll come back to how we + + align:start position:0% +as exogenous i'll come back to how we + + + align:start position:0% +as exogenous i'll come back to how we +pick it in a minute and the borrowing + + align:start position:0% +pick it in a minute and the borrowing + + + align:start position:0% +pick it in a minute and the borrowing +rates are exogenous we stick in for the + + align:start position:0% +rates are exogenous we stick in for the + + + align:start position:0% +rates are exogenous we stick in for the +interest rate what we observe the data + + align:start position:0% +interest rate what we observe the data + + + align:start position:0% +interest rate what we observe the data +we don't know about this relative price + + align:start position:0% +we don't know about this relative price + + + align:start position:0% +we don't know about this relative price +of the borrowing limit but we do + + align:start position:0% +of the borrowing limit but we do + + + align:start position:0% +of the borrowing limit but we do +have the profit sharing in each sector + + align:start position:0% +have the profit sharing in each sector + + + align:start position:0% +have the profit sharing in each sector +so we move the relative prices to match + + align:start position:0% +so we move the relative prices to match + + + align:start position:0% +so we move the relative prices to match +the profit share so for example + + align:start position:0% +the profit share so for example + + + align:start position:0% +the profit share so for example +if agriculture has a price pa + + align:start position:0% +if agriculture has a price pa + + + align:start position:0% +if agriculture has a price pa +uh and we observe a lot + + align:start position:0% +uh and we observe a lot + + + align:start position:0% +uh and we observe a lot +a large relative share + + align:start position:0% +a large relative share + + + align:start position:0% +a large relative share +of profits from agriculture + + align:start position:0% +of profits from agriculture + + + align:start position:0% +of profits from agriculture +then we + + align:start position:0% +then we + + + align:start position:0% +then we +imagine that it's a relatively high + + align:start position:0% +imagine that it's a relatively high + + + align:start position:0% +imagine that it's a relatively high +price of the agricultural good relative + + align:start position:0% +price of the agricultural good relative + + + align:start position:0% +price of the agricultural good relative +to the manufacturing good and vice versa + + align:start position:0% +to the manufacturing good and vice versa + + + align:start position:0% +to the manufacturing good and vice versa +likewise we're going to move the + + align:start position:0% +likewise we're going to move the + + + align:start position:0% +likewise we're going to move the +borrowing limit to match the observed + + align:start position:0% +borrowing limit to match the observed + + + align:start position:0% +borrowing limit to match the observed +weight rate + + align:start position:0% +weight rate + + + align:start position:0% +weight rate +the point being that if they can't + + align:start position:0% +the point being that if they can't + + + align:start position:0% +the point being that if they can't +borrow very much + + align:start position:0% +borrow very much + + + align:start position:0% +borrow very much +they're not going to have a very high + + align:start position:0% +they're not going to have a very high + + + align:start position:0% +they're not going to have a very high +scale of production + + align:start position:0% +scale of production + + + align:start position:0% +scale of production +they're not going to hire a lot of labor + + align:start position:0% +they're not going to hire a lot of labor + + + align:start position:0% +they're not going to hire a lot of labor +the demand for labor being low + + align:start position:0% +the demand for labor being low + + + align:start position:0% +the demand for labor being low +means the wage + + align:start position:0% +means the wage + + + align:start position:0% +means the wage +that has to clear the local market is + + align:start position:0% +that has to clear the local market is + + + align:start position:0% +that has to clear the local market is +going to be low + + align:start position:0% +going to be low + + + align:start position:0% +going to be low +the bigger picture here is calibration + + align:start position:0% +the bigger picture here is calibration + + + align:start position:0% +the bigger picture here is calibration +you have objects that matter a lot in + + align:start position:0% +you have objects that matter a lot in + + + align:start position:0% +you have objects that matter a lot in +the model + + align:start position:0% +the model + + + align:start position:0% +the model +and + + align:start position:0% +and + + + align:start position:0% +and +how you pick them + + align:start position:0% +how you pick them + + + align:start position:0% +how you pick them +well here we pick them + + align:start position:0% +well here we pick them + + + align:start position:0% +well here we pick them +by taking the data that we have + + align:start position:0% +by taking the data that we have + + + align:start position:0% +by taking the data that we have +and varying the parameters in the model + + align:start position:0% +and varying the parameters in the model + + + align:start position:0% +and varying the parameters in the model +in such a way that we can fit the model + + align:start position:0% +in such a way that we can fit the model + + + align:start position:0% +in such a way that we can fit the model +generated data to the actual data + + align:start position:0% +generated data to the actual data + + + align:start position:0% +generated data to the actual data +doing that we have to make a choice of + + align:start position:0% +doing that we have to make a choice of + + + align:start position:0% +doing that we have to make a choice of +which part of the actual data to use to + + align:start position:0% +which part of the actual data to use to + + + align:start position:0% +which part of the actual data to use to +calibrate which parameter + + align:start position:0% +calibrate which parameter + + + align:start position:0% +calibrate which parameter +and again read the dawkins thing and + + align:start position:0% +and again read the dawkins thing and + + + align:start position:0% +and again read the dawkins thing and +you'll see a discussion of this + + align:start position:0% +you'll see a discussion of this + + + align:start position:0% +you'll see a discussion of this +much more generally + + align:start position:0% +much more generally + + + align:start position:0% +much more generally +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so + + align:start position:0% +so + + + align:start position:0% +so +let's look at what happens how well are + + align:start position:0% +let's look at what happens how well are + + + align:start position:0% +let's look at what happens how well are +we doing oh these economists they come + + align:start position:0% +we doing oh these economists they come + + + align:start position:0% +we doing oh these economists they come +up with these models god knows how well + + align:start position:0% +up with these models god knows how well + + + align:start position:0% +up with these models god knows how well +they predict so i'll show you how well + + align:start position:0% +they predict so i'll show you how well + + + align:start position:0% +they predict so i'll show you how well +we're doing + + align:start position:0% +we're doing + + + align:start position:0% +we're doing +this is at the calibrated values for + + align:start position:0% +this is at the calibrated values for + + + align:start position:0% +this is at the calibrated values for +lopere i believe doesn't say that on the + + align:start position:0% +lopere i believe doesn't say that on the + + + align:start position:0% +lopere i believe doesn't say that on the +slide + + align:start position:0% +slide + + + align:start position:0% +slide +the actual level of output in the + + align:start position:0% +the actual level of output in the + + + align:start position:0% +the actual level of output in the +predicted level of output model + + align:start position:0% +predicted level of output model + + + align:start position:0% +predicted level of output model +predicted + + align:start position:0% +predicted + + + align:start position:0% +predicted +so we ran a successful experiment if you + + align:start position:0% +so we ran a successful experiment if you + + + align:start position:0% +so we ran a successful experiment if you +think about the model as an experiment + + align:start position:0% +think about the model as an experiment + + + align:start position:0% +think about the model as an experiment +populated by the + + align:start position:0% +populated by the + + + align:start position:0% +populated by the +parameters we calibrate then we are able + + align:start position:0% +parameters we calibrate then we are able + + + align:start position:0% +parameters we calibrate then we are able +to take this stylized model a la lucas + + align:start position:0% +to take this stylized model a la lucas + + + align:start position:0% +to take this stylized model a la lucas +and use it to interpret reality + + align:start position:0% +and use it to interpret reality + + + align:start position:0% +and use it to interpret reality +this is pretty close for consumption + + align:start position:0% +this is pretty close for consumption + + + align:start position:0% +this is pretty close for consumption +the actual being below the model + + align:start position:0% +the actual being below the model + + + align:start position:0% +the actual being below the model +so in this case they're consuming a + + align:start position:0% +so in this case they're consuming a + + + align:start position:0% +so in this case they're consuming a +little bit less than what the model says + + align:start position:0% +little bit less than what the model says + + + align:start position:0% +little bit less than what the model says +they might despite our attempt to fit it + + align:start position:0% +they might despite our attempt to fit it + + + align:start position:0% +they might despite our attempt to fit it +to the data + + align:start position:0% +to the data + + + align:start position:0% +to the data +and this is for + + align:start position:0% +and this is for + + + align:start position:0% +and this is for +assets which is very very close + + align:start position:0% +assets which is very very close + + + align:start position:0% +assets which is very very close +now these last three figures are all + + align:start position:0% +now these last three figures are all + + + align:start position:0% +now these last three figures are all +aggregated across all the households in + + align:start position:0% +aggregated across all the households in + + + align:start position:0% +aggregated across all the households in +a given economy + + align:start position:0% +a given economy + + + align:start position:0% +a given economy +okay so having sort of + + align:start position:0% +okay so having sort of + + + align:start position:0% +okay so having sort of +um oh and this is cash holdings + + align:start position:0% +um oh and this is cash holdings + + + align:start position:0% +um oh and this is cash holdings +which is you know one of our weak points + + align:start position:0% +which is you know one of our weak points + + + align:start position:0% +which is you know one of our weak points +uh and we're pretty close for a while + + align:start position:0% +uh and we're pretty close for a while + + + align:start position:0% +uh and we're pretty close for a while +and then cash holdings and the data + + align:start position:0% +and then cash holdings and the data + + + align:start position:0% +and then cash holdings and the data +still + + align:start position:0% +still + + + align:start position:0% +still +want to be higher than in the model god + + align:start position:0% +want to be higher than in the model god + + + align:start position:0% +want to be higher than in the model god +knows why they want that cash i + + align:start position:0% +knows why they want that cash i + + + align:start position:0% +knows why they want that cash i +we're just still dumbfounded + + align:start position:0% +we're just still dumbfounded + + + align:start position:0% +we're just still dumbfounded +that's the way they're saving + + align:start position:0% +that's the way they're saving + + + align:start position:0% +that's the way they're saving +over time in the aggregate accumulating + + align:start position:0% +over time in the aggregate accumulating + + + align:start position:0% +over time in the aggregate accumulating +claims on foreigners yeah that's the + + align:start position:0% +claims on foreigners yeah that's the + + + align:start position:0% +claims on foreigners yeah that's the +paper currency + + align:start position:0% +paper currency + + + align:start position:0% +paper currency +it's a claim on the central bank + + align:start position:0% +it's a claim on the central bank + + + align:start position:0% +it's a claim on the central bank +and they love it doesn't bear interest + + align:start position:0% +and they love it doesn't bear interest + + + align:start position:0% +and they love it doesn't bear interest +or anything but anyway i'll stop + + align:start position:0% +or anything but anyway i'll stop + + + align:start position:0% +or anything but anyway i'll stop +complaining okay + + align:start position:0% +complaining okay + + + align:start position:0% +complaining okay +so having done pretty well with the + + align:start position:0% +so having done pretty well with the + + + align:start position:0% +so having done pretty well with the +aggregates one hopes + + align:start position:0% +aggregates one hopes + + + align:start position:0% +aggregates one hopes +we've earned the right to talk about + + align:start position:0% +we've earned the right to talk about + + + align:start position:0% +we've earned the right to talk about +individual experiences now needless to + + align:start position:0% +individual experiences now needless to + + + align:start position:0% +individual experiences now needless to +say there are many households in a + + align:start position:0% +say there are many households in a + + + align:start position:0% +say there are many households in a +village and a non-trivial number of + + align:start position:0% +village and a non-trivial number of + + + align:start position:0% +village and a non-trivial number of +households in the sample we're fitting + + align:start position:0% +households in the sample we're fitting + + + align:start position:0% +households in the sample we're fitting +the aggregates you know via calibration + + align:start position:0% +the aggregates you know via calibration + + + align:start position:0% +the aggregates you know via calibration +i wouldn't expect perfect performance + + align:start position:0% +i wouldn't expect perfect performance + + + align:start position:0% +i wouldn't expect perfect performance +for each and every individual that's too + + align:start position:0% +for each and every individual that's too + + + align:start position:0% +for each and every individual that's too +much to hope for but let me show you how + + align:start position:0% +much to hope for but let me show you how + + + align:start position:0% +much to hope for but let me show you how +well we did with household a that labor + + align:start position:0% +well we did with household a that labor + + + align:start position:0% +well we did with household a that labor +household in loperi that we featured at + + align:start position:0% +household in loperi that we featured at + + + align:start position:0% +household in loperi that we featured at +the beginning + + align:start position:0% +the beginning + + + align:start position:0% +the beginning +so this is the actual + + align:start position:0% +so this is the actual + + + align:start position:0% +so this is the actual +darker line + + align:start position:0% +darker line + + + align:start position:0% +darker line +labor income i showed you this path + + align:start position:0% +labor income i showed you this path + + + align:start position:0% +labor income i showed you this path +before actually + + align:start position:0% +before actually + + + align:start position:0% +before actually +in wages and they went into agriculture + + align:start position:0% +in wages and they went into agriculture + + + align:start position:0% +in wages and they went into agriculture +livestock a bit they went into business + + align:start position:0% +livestock a bit they went into business + + + align:start position:0% +livestock a bit they went into business +and borrowed to do it + + align:start position:0% +and borrowed to do it + + + align:start position:0% +and borrowed to do it +this is the actual + + align:start position:0% +this is the actual + + + align:start position:0% +this is the actual +model prediction which is a lot flatter + + align:start position:0% +model prediction which is a lot flatter + + + align:start position:0% +model prediction which is a lot flatter +but it's not that far off + + align:start position:0% +but it's not that far off + + + align:start position:0% +but it's not that far off +matches pretty well at the beginning and + + align:start position:0% +matches pretty well at the beginning and + + + align:start position:0% +matches pretty well at the beginning and +the end + + align:start position:0% +the end + + + align:start position:0% +the end +this is consumption which is horrible + + align:start position:0% +this is consumption which is horrible + + + align:start position:0% +this is consumption which is horrible +so for this household + + align:start position:0% +so for this household + + + align:start position:0% +so for this household +the + + align:start position:0% +the + + + align:start position:0% +the +actual + + align:start position:0% +actual + + + align:start position:0% +actual +numbers drop lower than what the model + + align:start position:0% +numbers drop lower than what the model + + + align:start position:0% +numbers drop lower than what the model +says it ought to be + + align:start position:0% +says it ought to be + + + align:start position:0% +says it ought to be +and fixed assets is closer we do pretty + + align:start position:0% +and fixed assets is closer we do pretty + + + align:start position:0% +and fixed assets is closer we do pretty +well with fixed assets including at the + + align:start position:0% +well with fixed assets including at the + + + align:start position:0% +well with fixed assets including at the +individual household a level and cash + + align:start position:0% +individual household a level and cash + + + align:start position:0% +individual household a level and cash +again + + align:start position:0% +again + + + align:start position:0% +again +under and over going up though for both + + align:start position:0% +under and over going up though for both + + + align:start position:0% +under and over going up though for both +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so i'm tempted to put this in the u.s + + align:start position:0% +so i'm tempted to put this in the u.s + + + align:start position:0% +so i'm tempted to put this in the u.s +context because + + align:start position:0% +context because + + + align:start position:0% +context because +it may make it seem more real if you + + align:start position:0% +it may make it seem more real if you + + + align:start position:0% +it may make it seem more real if you +haven't been in thai villages + + align:start position:0% +haven't been in thai villages + + + align:start position:0% +haven't been in thai villages +what's the effect on farmers of + + align:start position:0% +what's the effect on farmers of + + + align:start position:0% +what's the effect on farmers of +restricted exports to china when china + + align:start position:0% +restricted exports to china when china + + + align:start position:0% +restricted exports to china when china +retaliated + + align:start position:0% +retaliated + + + align:start position:0% +retaliated +they came to an agreement but still + + align:start position:0% +they came to an agreement but still + + + align:start position:0% +they came to an agreement but still +china's not purchasing as much + + align:start position:0% +china's not purchasing as much + + + align:start position:0% +china's not purchasing as much +the other way around what about + + align:start position:0% +the other way around what about + + + align:start position:0% +the other way around what about +manufactured goods coming in from china + + align:start position:0% +manufactured goods coming in from china + + + align:start position:0% +manufactured goods coming in from china +what's the effect on wage earners + + align:start position:0% +what's the effect on wage earners + + + align:start position:0% +what's the effect on wage earners +that produce the thing which is now + + align:start position:0% +that produce the thing which is now + + + align:start position:0% +that produce the thing which is now +being imported + + align:start position:0% +being imported + + + align:start position:0% +being imported +whereas before had been produced + + align:start position:0% +whereas before had been produced + + + align:start position:0% +whereas before had been produced +domestically + + align:start position:0% +domestically + + + align:start position:0% +domestically +but we're going to talk about those + + align:start position:0% +but we're going to talk about those + + + align:start position:0% +but we're going to talk about those +things next time + + align:start position:0% +things next time + + + align:start position:0% +things next time +but we can already answer questions like + + align:start position:0% +but we can already answer questions like + + + align:start position:0% +but we can already answer questions like +this for thailand + + align:start position:0% +this for thailand + + + align:start position:0% +this for thailand +if for example we take the actual + + align:start position:0% +if for example we take the actual + + + align:start position:0% +if for example we take the actual +estimated model and run counterfactuals + + align:start position:0% +estimated model and run counterfactuals + + + align:start position:0% +estimated model and run counterfactuals +okay so suppose we impose trade + + align:start position:0% +okay so suppose we impose trade + + + align:start position:0% +okay so suppose we impose trade +frictions within the country + + align:start position:0% +frictions within the country + + + align:start position:0% +frictions within the country +what are tariffs going to do basically + + align:start position:0% +what are tariffs going to do basically + + + align:start position:0% +what are tariffs going to do basically +they hurt trade so if a village had been + + align:start position:0% +they hurt trade so if a village had been + + + align:start position:0% +they hurt trade so if a village had been +exporting a lot of agricultural goods + + align:start position:0% +exporting a lot of agricultural goods + + + align:start position:0% +exporting a lot of agricultural goods +and importing a lot of manufactured + + align:start position:0% +and importing a lot of manufactured + + + align:start position:0% +and importing a lot of manufactured +goods as in the northeast + + align:start position:0% +goods as in the northeast + + + align:start position:0% +goods as in the northeast +then the effect of a trade friction will + + align:start position:0% +then the effect of a trade friction will + + + align:start position:0% +then the effect of a trade friction will +increase + + align:start position:0% +increase + + + align:start position:0% +increase +the price of the thing that they they + + align:start position:0% +the price of the thing that they they + + + align:start position:0% +the price of the thing that they they +have been buying the import good + + align:start position:0% +have been buying the import good + + + align:start position:0% +have been buying the import good +and decrease the price of the export + + align:start position:0% +and decrease the price of the export + + + align:start position:0% +and decrease the price of the export +good + + align:start position:0% +good + + + align:start position:0% +good +hurt both ways + + align:start position:0% +hurt both ways + + + align:start position:0% +hurt both ways +we're going to do it by one percent so + + align:start position:0% +we're going to do it by one percent so + + + align:start position:0% +we're going to do it by one percent so +we're going to take these calibrated + + align:start position:0% +we're going to take these calibrated + + + align:start position:0% +we're going to take these calibrated +prices that match were used to match the + + align:start position:0% +prices that match were used to match the + + + align:start position:0% +prices that match were used to match the +payments to factors and profits and now + + align:start position:0% +payments to factors and profits and now + + + align:start position:0% +payments to factors and profits and now +vary them and see what happens + + align:start position:0% +vary them and see what happens + + + align:start position:0% +vary them and see what happens +we're also going to do a financial + + align:start position:0% +we're also going to do a financial + + + align:start position:0% +we're also going to do a financial +experiment in the model we're going to + + align:start position:0% +experiment in the model we're going to + + + align:start position:0% +experiment in the model we're going to +change the interest rate + + align:start position:0% +change the interest rate + + + align:start position:0% +change the interest rate +so it's like we're we're going to impede + + align:start position:0% +so it's like we're we're going to impede + + + align:start position:0% +so it's like we're we're going to impede +financial flows so again the effect of + + align:start position:0% +financial flows so again the effect of + + + align:start position:0% +financial flows so again the effect of +it always hurts so if the village had + + align:start position:0% +it always hurts so if the village had + + + align:start position:0% +it always hurts so if the village had +been in that lender + + align:start position:0% +been in that lender + + + align:start position:0% +been in that lender +for example + + align:start position:0% +for example + + + align:start position:0% +for example +then the effect of the financial + + align:start position:0% +then the effect of the financial + + + align:start position:0% +then the effect of the financial +friction + + align:start position:0% +friction + + + align:start position:0% +friction +is to make the interest rate lower + + align:start position:0% +is to make the interest rate lower + + + align:start position:0% +is to make the interest rate lower +because lenders don't like low interest + + align:start position:0% +because lenders don't like low interest + + + align:start position:0% +because lenders don't like low interest +rates we talked about that + + align:start position:0% +rates we talked about that + + + align:start position:0% +rates we talked about that +when we did the lecture on + + align:start position:0% +when we did the lecture on + + + align:start position:0% +when we did the lecture on +household income and price effects for + + align:start position:0% +household income and price effects for + + + align:start position:0% +household income and price effects for +households in the too good world anyway + + align:start position:0% +households in the too good world anyway + + + align:start position:0% +households in the too good world anyway +so if they're lending they're not going + + align:start position:0% +so if they're lending they're not going + + + align:start position:0% +so if they're lending they're not going +to like it that the interest rate goes + + align:start position:0% +to like it that the interest rate goes + + + align:start position:0% +to like it that the interest rate goes +down + + align:start position:0% +down + + + align:start position:0% +down +and likewise if they had been + + align:start position:0% +and likewise if they had been + + + align:start position:0% +and likewise if they had been +borrowing we would have gone the other + + align:start position:0% +borrowing we would have gone the other + + + align:start position:0% +borrowing we would have gone the other +way and make the loans more expensive so + + align:start position:0% +way and make the loans more expensive so + + + align:start position:0% +way and make the loans more expensive so +that's the effect of + + align:start position:0% +that's the effect of + + + align:start position:0% +that's the effect of +the way we capture in the model in order + + align:start position:0% +the way we capture in the model in order + + + align:start position:0% +the way we capture in the model in order +to run and experiment + + align:start position:0% +to run and experiment + + + align:start position:0% +to run and experiment +uh the impact of trade frictions through + + align:start position:0% +uh the impact of trade frictions through + + + align:start position:0% +uh the impact of trade frictions through +tariffs and + + align:start position:0% +tariffs and + + + align:start position:0% +tariffs and +or internal frictions + + align:start position:0% +or internal frictions + + + align:start position:0% +or internal frictions +and financial frictions okay so + + align:start position:0% +and financial frictions okay so + + + align:start position:0% +and financial frictions okay so +you want to see what happens + + align:start position:0% +you want to see what happens + + + align:start position:0% +you want to see what happens +uh this is in lopere and this is the + + align:start position:0% +uh this is in lopere and this is the + + + align:start position:0% +uh this is in lopere and this is the +effect of that one percent increase in + + align:start position:0% +effect of that one percent increase in + + + align:start position:0% +effect of that one percent increase in +trade frictions + + align:start position:0% +trade frictions + + + align:start position:0% +trade frictions +making exports give less revenue imports + + align:start position:0% +making exports give less revenue imports + + + align:start position:0% +making exports give less revenue imports +now cost more + + align:start position:0% +now cost more + + + align:start position:0% +now cost more +that's going to affect the production + + align:start position:0% +that's going to affect the production + + + align:start position:0% +that's going to affect the production +and profits from the manufactured good + + align:start position:0% +and profits from the manufactured good + + + align:start position:0% +and profits from the manufactured good +and the agricultural good and in turn + + align:start position:0% +and the agricultural good and in turn + + + align:start position:0% +and the agricultural good and in turn +remember the algorithm from last time + + align:start position:0% +remember the algorithm from last time + + + align:start position:0% +remember the algorithm from last time +that i reviewed + + align:start position:0% +that i reviewed + + + align:start position:0% +that i reviewed +those price changes are going to map + + align:start position:0% +those price changes are going to map + + + align:start position:0% +those price changes are going to map +into + + align:start position:0% +into + + + align:start position:0% +into +input quantities are going to map into + + align:start position:0% +input quantities are going to map into + + + align:start position:0% +input quantities are going to map into +relative factor price movements okay but + + align:start position:0% +relative factor price movements okay but + + + align:start position:0% +relative factor price movements okay but +there's a lot of diversity in these + + align:start position:0% +there's a lot of diversity in these + + + align:start position:0% +there's a lot of diversity in these +economies + + align:start position:0% +economies + + + align:start position:0% +economies +as i've been saying households differ by + + align:start position:0% +as i've been saying households differ by + + + align:start position:0% +as i've been saying households differ by +their initial level of capital they + + align:start position:0% +their initial level of capital they + + + align:start position:0% +their initial level of capital they +differ also by their talent so we have + + align:start position:0% +differ also by their talent so we have + + + align:start position:0% +differ also by their talent so we have +capital moving on the x-axis and the + + align:start position:0% +capital moving on the x-axis and the + + + align:start position:0% +capital moving on the x-axis and the +average skill level pretty high skill + + align:start position:0% +average skill level pretty high skill + + + align:start position:0% +average skill level pretty high skill +level and very high skill level and then + + align:start position:0% +level and very high skill level and then + + + align:start position:0% +level and very high skill level and then +what's getting plotted here is the gains + + align:start position:0% +what's getting plotted here is the gains + + + align:start position:0% +what's getting plotted here is the gains +or losses so + + align:start position:0% +or losses so + + + align:start position:0% +or losses so +it's a tariff effectively + + align:start position:0% +it's a tariff effectively + + + align:start position:0% +it's a tariff effectively +so you might expect losses + + align:start position:0% +so you might expect losses + + + align:start position:0% +so you might expect losses +and in fact these average or low skilled + + align:start position:0% +and in fact these average or low skilled + + + align:start position:0% +and in fact these average or low skilled +guys do suffer losses + + align:start position:0% +guys do suffer losses + + + align:start position:0% +guys do suffer losses +arguably because they're wage earners + + align:start position:0% +arguably because they're wage earners + + + align:start position:0% +arguably because they're wage earners +although you can't see that + + align:start position:0% +although you can't see that + + + align:start position:0% +although you can't see that +and + + align:start position:0% +and + + + align:start position:0% +and +the + + align:start position:0% +the + + + align:start position:0% +the +movement in production + + align:start position:0% +movement in production + + + align:start position:0% +movement in production +from the capital good and the labor + + align:start position:0% +from the capital good and the labor + + + align:start position:0% +from the capital good and the labor +intensive good + + align:start position:0% +intensive good + + + align:start position:0% +intensive good +was such as to hurt the wage so remember + + align:start position:0% +was such as to hurt the wage so remember + + + align:start position:0% +was such as to hurt the wage so remember +we did stolper samuelson where an + + align:start position:0% +we did stolper samuelson where an + + + align:start position:0% +we did stolper samuelson where an +increase in the price causes an increase + + align:start position:0% +increase in the price causes an increase + + + align:start position:0% +increase in the price causes an increase +in the factor price of the good that is + + align:start position:0% +in the factor price of the good that is + + + align:start position:0% +in the factor price of the good that is +used relatively intensively so despite + + align:start position:0% +used relatively intensively so despite + + + align:start position:0% +used relatively intensively so despite +all the differences with the two by two + + align:start position:0% +all the differences with the two by two + + + align:start position:0% +all the differences with the two by two +from last time that ingredient is + + align:start position:0% +from last time that ingredient is + + + align:start position:0% +from last time that ingredient is +playing a role here + + align:start position:0% +playing a role here + + + align:start position:0% +playing a role here +so these wage earners are hurt initially + + align:start position:0% +so these wage earners are hurt initially + + + align:start position:0% +so these wage earners are hurt initially +but then ironically as we move in the + + align:start position:0% +but then ironically as we move in the + + + align:start position:0% +but then ironically as we move in the +cross section for a higher level of + + align:start position:0% +cross section for a higher level of + + + align:start position:0% +cross section for a higher level of +capital they were actually producers not + + align:start position:0% +capital they were actually producers not + + + align:start position:0% +capital they were actually producers not +wage earners and now the lower wage + + align:start position:0% +wage earners and now the lower wage + + + align:start position:0% +wage earners and now the lower wage +helps them because it's an a lowered + + align:start position:0% +helps them because it's an a lowered + + + align:start position:0% +helps them because it's an a lowered +cost of production so their profits go + + align:start position:0% +cost of production so their profits go + + + align:start position:0% +cost of production so their profits go +up now they're they're winning by a + + align:start position:0% +up now they're they're winning by a + + + align:start position:0% +up now they're they're winning by a +little less than one percent and you + + align:start position:0% +little less than one percent and you + + + align:start position:0% +little less than one percent and you +know if they're really really talented + + align:start position:0% +know if they're really really talented + + + align:start position:0% +know if they're really really talented +they've been producing at a higher scale + + align:start position:0% +they've been producing at a higher scale + + + align:start position:0% +they've been producing at a higher scale +all along so the drop in wages you know + + align:start position:0% +all along so the drop in wages you know + + + align:start position:0% +all along so the drop in wages you know +is even better for them + + align:start position:0% +is even better for them + + + align:start position:0% +is even better for them +okay + + align:start position:0% +okay + + + align:start position:0% +okay +i'm trying to give you some intuition + + align:start position:0% +i'm trying to give you some intuition + + + align:start position:0% +i'm trying to give you some intuition +here but i decided because time was + + align:start position:0% +here but i decided because time was + + + align:start position:0% +here but i decided because time was +short i wouldn't be able to actually + + align:start position:0% +short i wouldn't be able to actually + + + align:start position:0% +short i wouldn't be able to actually +prove all these assertions + + align:start position:0% +prove all these assertions + + + align:start position:0% +prove all these assertions +i'm just asking you to sort of imagine + + align:start position:0% +i'm just asking you to sort of imagine + + + align:start position:0% +i'm just asking you to sort of imagine +from the two by two by two that we did + + align:start position:0% +from the two by two by two that we did + + + align:start position:0% +from the two by two by two that we did +last time you know why it is we're + + align:start position:0% +last time you know why it is we're + + + align:start position:0% +last time you know why it is we're +seeing all this diversity here + + align:start position:0% +seeing all this diversity here + + + align:start position:0% +seeing all this diversity here +oh the order of magnitude is like less + + align:start position:0% +oh the order of magnitude is like less + + + align:start position:0% +oh the order of magnitude is like less +than one percent here it's one percent + + align:start position:0% +than one percent here it's one percent + + + align:start position:0% +than one percent here it's one percent +so that's pretty small but if you looked + + align:start position:0% +so that's pretty small but if you looked + + + align:start position:0% +so that's pretty small but if you looked +at the financial frictions + + align:start position:0% +at the financial frictions + + + align:start position:0% +at the financial frictions +in lopere + + align:start position:0% +in lopere + + + align:start position:0% +in lopere +in the sense that i described you you + + align:start position:0% +in the sense that i described you you + + + align:start position:0% +in the sense that i described you you +can see bigger numbers first of all you + + align:start position:0% +can see bigger numbers first of all you + + + align:start position:0% +can see bigger numbers first of all you +see winners and losers + + align:start position:0% +see winners and losers + + + align:start position:0% +see winners and losers +you also see that it matters whether + + align:start position:0% +you also see that it matters whether + + + align:start position:0% +you also see that it matters whether +they were wage earners or capitalists + + align:start position:0% +they were wage earners or capitalists + + + align:start position:0% +they were wage earners or capitalists +but above all you see + + align:start position:0% +but above all you see + + + align:start position:0% +but above all you see +that the + + align:start position:0% +that the + + + align:start position:0% +that the +high skilled guys + + align:start position:0% +high skilled guys + + + align:start position:0% +high skilled guys +can benefit up to 10 + + align:start position:0% +can benefit up to 10 + + + align:start position:0% +can benefit up to 10 +from the increase in the interest rate + + align:start position:0% +from the increase in the interest rate + + + align:start position:0% +from the increase in the interest rate +that's associated with + + align:start position:0% +that's associated with + + + align:start position:0% +that's associated with +the uh financial friction + + align:start position:0% +the uh financial friction + + + align:start position:0% +the uh financial friction +because the country had been borrowing + + align:start position:0% +because the country had been borrowing + + + align:start position:0% +because the country had been borrowing +the village had been borrowing but some + + align:start position:0% +the village had been borrowing but some + + + align:start position:0% +the village had been borrowing but some +of those guys don't borrow they lend + + align:start position:0% +of those guys don't borrow they lend + + + align:start position:0% +of those guys don't borrow they lend +and likewise + + align:start position:0% +and likewise + + + align:start position:0% +and likewise +there are other people here + + align:start position:0% +there are other people here + + + align:start position:0% +there are other people here +the average skilled guys who are taking + + align:start position:0% +the average skilled guys who are taking + + + align:start position:0% +the average skilled guys who are taking +big losses of up to 10 + + align:start position:0% +big losses of up to 10 + + + align:start position:0% +big losses of up to 10 +so again one could imagine + + align:start position:0% +so again one could imagine + + + align:start position:0% +so again one could imagine +producing pictures like this + + align:start position:0% +producing pictures like this + + + align:start position:0% +producing pictures like this +and if we go back to household a + + align:start position:0% +and if we go back to household a + + + align:start position:0% +and if we go back to household a +like what happens to + + align:start position:0% +like what happens to + + + align:start position:0% +like what happens to +a wage earner in the u.s with + + align:start position:0% +a wage earner in the u.s with + + + align:start position:0% +a wage earner in the u.s with +manufactured imports + + align:start position:0% +manufactured imports + + + align:start position:0% +manufactured imports +or a farmer in the midwest with + + align:start position:0% +or a farmer in the midwest with + + + align:start position:0% +or a farmer in the midwest with +agricultural exports what happens in + + align:start position:0% +agricultural exports what happens in + + + align:start position:0% +agricultural exports what happens in +loperi + + align:start position:0% +loperi + + + align:start position:0% +loperi +to that wage earner + + align:start position:0% +to that wage earner + + + align:start position:0% +to that wage earner +under you know the trade friction + + align:start position:0% +under you know the trade friction + + + align:start position:0% +under you know the trade friction +or under the financial friction they + + align:start position:0% +or under the financial friction they + + + align:start position:0% +or under the financial friction they +lose + + align:start position:0% +lose + + + align:start position:0% +lose +he lose he or she loses that household + + align:start position:0% +he lose he or she loses that household + + + align:start position:0% +he lose he or she loses that household +loses so we validated the model to try + + align:start position:0% +loses so we validated the model to try + + + align:start position:0% +loses so we validated the model to try +to make this realistic it fit pretty + + align:start position:0% +to make this realistic it fit pretty + + + align:start position:0% +to make this realistic it fit pretty +well + + align:start position:0% +well + + + align:start position:0% +well +very well to the aggregate level it fit + + align:start position:0% +very well to the aggregate level it fit + + + align:start position:0% +very well to the aggregate level it fit +pretty well at the individual level so + + align:start position:0% +pretty well at the individual level so + + + align:start position:0% +pretty well at the individual level so +if for some reason the thai government + + align:start position:0% +if for some reason the thai government + + + align:start position:0% +if for some reason the thai government +had run this experiment or they had + + align:start position:0% +had run this experiment or they had + + + align:start position:0% +had run this experiment or they had +political + + align:start position:0% +political + + + align:start position:0% +political +issues that made the country more + + align:start position:0% +issues that made the country more + + + align:start position:0% +issues that made the country more +isolated you could see the effect of + + align:start position:0% +isolated you could see the effect of + + + align:start position:0% +isolated you could see the effect of +that on individual households through + + align:start position:0% +that on individual households through + + + align:start position:0% +that on individual households through +through the lens of the model okay + + align:start position:0% +through the lens of the model okay + + + align:start position:0% +through the lens of the model okay +any final questions + + align:start position:0% +any final questions + + + align:start position:0% +any final questions +so again we'll kind of do it all over + + align:start position:0% +so again we'll kind of do it all over + + + align:start position:0% +so again we'll kind of do it all over +again when we when we come to the u.s + + align:start position:0% +again when we when we come to the u.s + + + align:start position:0% +again when we when we come to the u.s +next time next thursday \ No newline at end of file diff --git a/RoTz_ylFHfY.txt b/RoTz_ylFHfY.txt new file mode 100644 index 0000000000000000000000000000000000000000..6282411dac336a312fe7a4c85e51ce5f8cacbc2e --- /dev/null +++ b/RoTz_ylFHfY.txt @@ -0,0 +1,2363 @@ +align:start position:0% + +welcome back to recitation in this video + + align:start position:0% +welcome back to recitation in this video + + + align:start position:0% +welcome back to recitation in this video +I'd like us to work on the following + + align:start position:0% +I'd like us to work on the following + + + align:start position:0% +I'd like us to work on the following +problem we're going to let capital D + + align:start position:0% +problem we're going to let capital D + + + align:start position:0% +problem we're going to let capital D +denote the portion of the sphere the + + align:start position:0% +denote the portion of the sphere the + + + align:start position:0% +denote the portion of the sphere the +solid sphere of radius one that's + + align:start position:0% +solid sphere of radius one that's + + + align:start position:0% +solid sphere of radius one that's +centered at + + align:start position:0% +centered at + + + align:start position:0% +centered at +001 which also lies above the plane zal + + align:start position:0% +001 which also lies above the plane zal + + + align:start position:0% +001 which also lies above the plane zal +1 and then I'd like us to First Supply + + align:start position:0% +1 and then I'd like us to First Supply + + + align:start position:0% +1 and then I'd like us to First Supply +the limits for D and spherical + + align:start position:0% +the limits for D and spherical + + + align:start position:0% +the limits for D and spherical +coordinates in other words I want you to + + align:start position:0% +coordinates in other words I want you to + + + align:start position:0% +coordinates in other words I want you to +determine the values for row Theta and f + + align:start position:0% +determine the values for row Theta and f + + + align:start position:0% +determine the values for row Theta and f +that will give us all of D and then I + + align:start position:0% +that will give us all of D and then I + + + align:start position:0% +that will give us all of D and then I +would like us to just set up the + + align:start position:0% +would like us to just set up the + + + align:start position:0% +would like us to just set up the +integral for the average distance of a + + align:start position:0% +integral for the average distance of a + + + align:start position:0% +integral for the average distance of a +point in D from the origin so there are + + align:start position:0% +point in D from the origin so there are + + + align:start position:0% +point in D from the origin so there are +two parts to this problem the first is + + align:start position:0% +two parts to this problem the first is + + + align:start position:0% +two parts to this problem the first is +to determine what values of row Theta + + align:start position:0% +to determine what values of row Theta + + + align:start position:0% +to determine what values of row Theta +and Fe describe this region this this + + align:start position:0% +and Fe describe this region this this + + + align:start position:0% +and Fe describe this region this this +solid region D and then second is just + + align:start position:0% +solid region D and then second is just + + + align:start position:0% +solid region D and then second is just +set up the integral for the average + + align:start position:0% +set up the integral for the average + + + align:start position:0% +set up the integral for the average +distance of a point in that region from + + align:start position:0% +distance of a point in that region from + + + align:start position:0% +distance of a point in that region from +the origin so why don't you pause the + + align:start position:0% +the origin so why don't you pause the + + + align:start position:0% +the origin so why don't you pause the +video work on those and then when you're + + align:start position:0% +video work on those and then when you're + + + align:start position:0% +video work on those and then when you're +ready to see my Solutions you can bring + + align:start position:0% +ready to see my Solutions you can bring + + + align:start position:0% +ready to see my Solutions you can bring +the video back + + align:start position:0% + + + + align:start position:0% + +up okay welcome back well I would say + + align:start position:0% +up okay welcome back well I would say + + + align:start position:0% +up okay welcome back well I would say +from looking at this problem actually + + align:start position:0% +from looking at this problem actually + + + align:start position:0% +from looking at this problem actually +part A is potentially a little bit more + + align:start position:0% +part A is potentially a little bit more + + + align:start position:0% +part A is potentially a little bit more +hazardous for some of us than Part B + + align:start position:0% +hazardous for some of us than Part B + + + align:start position:0% +hazardous for some of us than Part B +once we know the the bounds that + + align:start position:0% +once we know the the bounds that + + + align:start position:0% +once we know the the bounds that +describe D it's not too hard to set up + + align:start position:0% +describe D it's not too hard to set up + + + align:start position:0% +describe D it's not too hard to set up +this integral so the hard part of this + + align:start position:0% +this integral so the hard part of this + + + align:start position:0% +this integral so the hard part of this +problem is understanding how to write + + align:start position:0% +problem is understanding how to write + + + align:start position:0% +problem is understanding how to write +this solid region D in spherical + + align:start position:0% +this solid region D in spherical + + + align:start position:0% +this solid region D in spherical +coordinates but it's actually really not + + align:start position:0% +coordinates but it's actually really not + + + align:start position:0% +coordinates but it's actually really not +that hard either so I'm going to try and + + align:start position:0% +that hard either so I'm going to try and + + + align:start position:0% +that hard either so I'm going to try and +take us through it in a reasonable way + + align:start position:0% +take us through it in a reasonable way + + + align:start position:0% +take us through it in a reasonable way +so the first thing I'm going to draw a + + align:start position:0% +so the first thing I'm going to draw a + + + align:start position:0% +so the first thing I'm going to draw a +very rough picture of the region so we + + align:start position:0% +very rough picture of the region so we + + + align:start position:0% +very rough picture of the region so we +understand what it looks like so in + + align:start position:0% +understand what it looks like so in + + + align:start position:0% +understand what it looks like so in +order to do part A and if you did not do + + align:start position:0% +order to do part A and if you did not do + + + align:start position:0% +order to do part A and if you did not do +this I would highly recommend that next + + align:start position:0% +this I would highly recommend that next + + + align:start position:0% +this I would highly recommend that next +time you encounter such a problem you + + align:start position:0% +time you encounter such a problem you + + + align:start position:0% +time you encounter such a problem you +begin by drawing yourself a picture even + + align:start position:0% +begin by drawing yourself a picture even + + + align:start position:0% +begin by drawing yourself a picture even +if it's not a gr picture it will give + + align:start position:0% +if it's not a gr picture it will give + + + align:start position:0% +if it's not a gr picture it will give +you some intuition about what's + + align:start position:0% +you some intuition about what's + + + align:start position:0% +you some intuition about what's +happening so let me first first draw the + + align:start position:0% +happening so let me first first draw the + + + align:start position:0% +happening so let me first first draw the +axes and ultimately what I have is say + + align:start position:0% +axes and ultimately what I have is say + + + align:start position:0% +axes and ultimately what I have is say +here is the + + align:start position:0% +here is the + + + align:start position:0% +here is the +01 I have a + + align:start position:0% +01 I have a + + + align:start position:0% +01 I have a +sphere that's looking in in the x or + + align:start position:0% +sphere that's looking in in the x or + + + align:start position:0% +sphere that's looking in in the x or +sorry in the z y plane it looks + + align:start position:0% +sorry in the z y plane it looks + + + align:start position:0% +sorry in the z y plane it looks +something like + + align:start position:0% +something like + + + align:start position:0% +something like +this and then so it has this depth + + align:start position:0% +this and then so it has this depth + + + align:start position:0% +this and then so it has this depth +here and that's the solid sphere I want + + align:start position:0% +here and that's the solid sphere I want + + + align:start position:0% +here and that's the solid sphere I want +to be considering and then I'm going to + + align:start position:0% +to be considering and then I'm going to + + + align:start position:0% +to be considering and then I'm going to +be removing the bottom half I'm only + + align:start position:0% +be removing the bottom half I'm only + + + align:start position:0% +be removing the bottom half I'm only +going to be looking at the part that is + + align:start position:0% +going to be looking at the part that is + + + align:start position:0% +going to be looking at the part that is +above the zal 1 plane so it's actually + + align:start position:0% +above the zal 1 plane so it's actually + + + align:start position:0% +above the zal 1 plane so it's actually +going to look it's going to be all the + + align:start position:0% +going to look it's going to be all the + + + align:start position:0% +going to look it's going to be all the +circular + + align:start position:0% +circular + + + align:start position:0% +circular +slices that are in the the top half sort + + align:start position:0% +slices that are in the the top half sort + + + align:start position:0% +slices that are in the the top half sort +of the upper hemisphere of this sphere + + align:start position:0% +of the upper hemisphere of this sphere + + + align:start position:0% +of the upper hemisphere of this sphere +and so it's the solid region there + + align:start position:0% +and so it's the solid region there + + + align:start position:0% +and so it's the solid region there +that's D and what I want to do to + + align:start position:0% +that's D and what I want to do to + + + align:start position:0% +that's D and what I want to do to +determine uh row and and Theta and Fe + + align:start position:0% +determine uh row and and Theta and Fe + + + align:start position:0% +determine uh row and and Theta and Fe +actually the Theta is the easy one right + + align:start position:0% +actually the Theta is the easy one right + + + align:start position:0% +actually the Theta is the easy one right +because Theta at each at each value here + + align:start position:0% +because Theta at each at each value here + + + align:start position:0% +because Theta at each at each value here +I go all the way around in the Theta + + align:start position:0% +I go all the way around in the Theta + + + align:start position:0% +I go all the way around in the Theta +Direction so I know I'm going to go at + + align:start position:0% +Direction so I know I'm going to go at + + + align:start position:0% +Direction so I know I'm going to go at +any given at any given height or radius + + align:start position:0% +any given at any given height or radius + + + align:start position:0% +any given at any given height or radius +I want to go all the way around in the + + align:start position:0% +I want to go all the way around in the + + + align:start position:0% +I want to go all the way around in the +Theta direction from 0 to 2 pi so my + + align:start position:0% +Theta direction from 0 to 2 pi so my + + + align:start position:0% +Theta direction from 0 to 2 pi so my +Theta bounds are the easy ones that's + + align:start position:0% +Theta bounds are the easy ones that's + + + align:start position:0% +Theta bounds are the easy ones that's +just I'm covering it I'm covering 0 to 2 + + align:start position:0% +just I'm covering it I'm covering 0 to 2 + + + align:start position:0% +just I'm covering it I'm covering 0 to 2 +pi in Theta I'm not because that would + + align:start position:0% +pi in Theta I'm not because that would + + + align:start position:0% +pi in Theta I'm not because that would +if I cut off the back half of the circle + + align:start position:0% +if I cut off the back half of the circle + + + align:start position:0% +if I cut off the back half of the circle +that would change my values of theta but + + align:start position:0% +that would change my values of theta but + + + align:start position:0% +that would change my values of theta but +because I'm sorry not Circle sphere the + + align:start position:0% +because I'm sorry not Circle sphere the + + + align:start position:0% +because I'm sorry not Circle sphere the +back half of the sphere I'd want to only + + align:start position:0% +back half of the sphere I'd want to only + + + align:start position:0% +back half of the sphere I'd want to only +have a restricted value of theta but + + align:start position:0% +have a restricted value of theta but + + + align:start position:0% +have a restricted value of theta but +because I'm covering sort of all the way + + align:start position:0% +because I'm covering sort of all the way + + + align:start position:0% +because I'm covering sort of all the way +around and my restriction is only sort + + align:start position:0% +around and my restriction is only sort + + + align:start position:0% +around and my restriction is only sort +of bottom half my Theta values haven't + + align:start position:0% +of bottom half my Theta values haven't + + + align:start position:0% +of bottom half my Theta values haven't +changed so Theta is easy 0 and 2 + + align:start position:0% +changed so Theta is easy 0 and 2 + + + align:start position:0% +changed so Theta is easy 0 and 2 +pi now the harder ones are going to be + + align:start position:0% +pi now the harder ones are going to be + + + align:start position:0% +pi now the harder ones are going to be +row and Fe but in fact actually Fe is + + align:start position:0% +row and Fe but in fact actually Fe is + + + align:start position:0% +row and Fe but in fact actually Fe is +not that hard either Fe I notice I'm + + align:start position:0% +not that hard either Fe I notice I'm + + + align:start position:0% +not that hard either Fe I notice I'm +starting Fe is the angle that I make + + align:start position:0% +starting Fe is the angle that I make + + + align:start position:0% +starting Fe is the angle that I make +from the z-axis to any given point so I + + align:start position:0% +from the z-axis to any given point so I + + + align:start position:0% +from the z-axis to any given point so I +notice that I certainly I'm including + + align:start position:0% +notice that I certainly I'm including + + + align:start position:0% +notice that I certainly I'm including +the point where Fe is zero and then I'm + + align:start position:0% +the point where Fe is zero and then I'm + + + align:start position:0% +the point where Fe is zero and then I'm +going all the way down to a point out + + align:start position:0% +going all the way down to a point out + + + align:start position:0% +going all the way down to a point out +here which is 45° angle with the z-axis + + align:start position:0% +here which is 45° angle with the z-axis + + + align:start position:0% +here which is 45° angle with the z-axis +so f is also easy it's actually just + + align:start position:0% +so f is also easy it's actually just + + + align:start position:0% +so f is also easy it's actually just +between 0 and pi over + + align:start position:0% + + + + align:start position:0% + +4 and the row will be the slightly + + align:start position:0% +4 and the row will be the slightly + + + align:start position:0% +4 and the row will be the slightly +harder part so that's the really the + + align:start position:0% +harder part so that's the really the + + + align:start position:0% +harder part so that's the really the +only real tricky part in this problem is + + align:start position:0% +only real tricky part in this problem is + + + align:start position:0% +only real tricky part in this problem is +determining the row value now the row + + align:start position:0% +determining the row value now the row + + + align:start position:0% +determining the row value now the row +value to get the outer boundary we'll + + align:start position:0% +value to get the outer boundary we'll + + + align:start position:0% +value to get the outer boundary we'll +look at that part first to get the outer + + align:start position:0% +look at that part first to get the outer + + + align:start position:0% +look at that part first to get the outer +boundary well the boundary of of this + + align:start position:0% +boundary well the boundary of of this + + + align:start position:0% +boundary well the boundary of of this +sphere here has a certain equation in X + + align:start position:0% +sphere here has a certain equation in X + + + align:start position:0% +sphere here has a certain equation in X +Y and Z that we know right it's x^2 + + + align:start position:0% +Y and Z that we know right it's x^2 + + + + align:start position:0% +Y and Z that we know right it's x^2 + +y^2 plus the quantity zus 1^ 2 equals 1 + + align:start position:0% +y^2 plus the quantity zus 1^ 2 equals 1 + + + align:start position:0% +y^2 plus the quantity zus 1^ 2 equals 1 +I mean that's just the the equation for + + align:start position:0% +I mean that's just the the equation for + + + align:start position:0% +I mean that's just the the equation for +a sphere of radius 1 centered at 0 0 1 + + align:start position:0% +a sphere of radius 1 centered at 0 0 1 + + + align:start position:0% +a sphere of radius 1 centered at 0 0 1 +so I'm going to write that here and + + align:start position:0% +so I'm going to write that here and + + + align:start position:0% +so I'm going to write that here and +we're going to show how we can + + align:start position:0% +we're going to show how we can + + + align:start position:0% +we're going to show how we can +manipulate + + align:start position:0% + + + + align:start position:0% + +that right x^2 + y^2 is R 2 R 2 is Row 2 + + align:start position:0% +that right x^2 + y^2 is R 2 R 2 is Row 2 + + + align:start position:0% +that right x^2 + y^2 is R 2 R 2 is Row 2 +sin 2 so I can replace this by Row 2 + + align:start position:0% +sin 2 so I can replace this by Row 2 + + + align:start position:0% +sin 2 so I can replace this by Row 2 +sin^2 if you didn't know that + + align:start position:0% +sin^2 if you didn't know that + + + align:start position:0% +sin^2 if you didn't know that +immediately you could make the + + align:start position:0% +immediately you could make the + + + align:start position:0% +immediately you could make the +substitution for x and y in spherical + + align:start position:0% +substitution for x and y in spherical + + + align:start position:0% +substitution for x and y in spherical +coordinates and it simplifies to this so + + align:start position:0% +coordinates and it simplifies to this so + + + align:start position:0% +coordinates and it simplifies to this so +either way if you didn't know r s was + + align:start position:0% +either way if you didn't know r s was + + + align:start position:0% +either way if you didn't know r s was +this you can you can get it from just + + align:start position:0% +this you can you can get it from just + + + align:start position:0% +this you can you can get it from just +doing the substitution and then Z is + + align:start position:0% +doing the substitution and then Z is + + + align:start position:0% +doing the substitution and then Z is +going to be row cosine Fe so here I'm + + align:start position:0% +going to be row cosine Fe so here I'm + + + align:start position:0% +going to be row cosine Fe so here I'm +going to have a row cosine Fe - 1^ 2 1 + + align:start position:0% +going to have a row cosine Fe - 1^ 2 1 + + + align:start position:0% +going to have a row cosine Fe - 1^ 2 1 +this in the spherical coordinates is + + align:start position:0% +this in the spherical coordinates is + + + align:start position:0% +this in the spherical coordinates is +describing the boundary of this entire + + align:start position:0% +describing the boundary of this entire + + + align:start position:0% +describing the boundary of this entire +sphere right and so I can actually + + align:start position:0% +sphere right and so I can actually + + + align:start position:0% +sphere right and so I can actually +simplify this it's not too hard if I + + align:start position:0% +simplify this it's not too hard if I + + + align:start position:0% +simplify this it's not too hard if I +Square this I get a little cancellation + + align:start position:0% +Square this I get a little cancellation + + + align:start position:0% +Square this I get a little cancellation +and then because I want my row to be I'm + + align:start position:0% +and then because I want my row to be I'm + + + align:start position:0% +and then because I want my row to be I'm +assuming in this region row is greater + + align:start position:0% +assuming in this region row is greater + + + align:start position:0% +assuming in this region row is greater +than zero I can do a little + + align:start position:0% +than zero I can do a little + + + align:start position:0% +than zero I can do a little +simplification I come up with the fact + + align:start position:0% +simplification I come up with the fact + + + align:start position:0% +simplification I come up with the fact +that row is equal to 2 cosine V and + + align:start position:0% +that row is equal to 2 cosine V and + + + align:start position:0% +that row is equal to 2 cosine V and +let's describe exactly where that is + + align:start position:0% +let's describe exactly where that is + + + align:start position:0% +let's describe exactly where that is +that's the entire boundary of this + + align:start position:0% +that's the entire boundary of this + + + align:start position:0% +that's the entire boundary of this +entire sphere is described by row is + + align:start position:0% +entire sphere is described by row is + + + align:start position:0% +entire sphere is described by row is +equal to 2 cosine + + align:start position:0% +equal to 2 cosine + + + align:start position:0% +equal to 2 cosine +V and so if I want to think about what + + align:start position:0% +V and so if I want to think about what + + + align:start position:0% +V and so if I want to think about what +my bounds are for row I'm actually going + + align:start position:0% +my bounds are for row I'm actually going + + + align:start position:0% +my bounds are for row I'm actually going +to grab a piece of colored + + align:start position:0% +to grab a piece of colored + + + align:start position:0% +to grab a piece of colored +chalk if I start at the origin I think + + align:start position:0% +chalk if I start at the origin I think + + + align:start position:0% +chalk if I start at the origin I think +about what is row so this say this is a + + align:start position:0% +about what is row so this say this is a + + + align:start position:0% +about what is row so this say this is a +point on the boundary of the sphere I'm + + align:start position:0% +point on the boundary of the sphere I'm + + + align:start position:0% +point on the boundary of the sphere I'm +going to start my row value whatever it + + align:start position:0% +going to start my row value whatever it + + + align:start position:0% +going to start my row value whatever it +is when it hits the plane Z equals 1 and + + align:start position:0% +is when it hits the plane Z equals 1 and + + + align:start position:0% +is when it hits the plane Z equals 1 and +I'm going to stop it when it hits the + + align:start position:0% +I'm going to stop it when it hits the + + + align:start position:0% +I'm going to stop it when it hits the +boundary of the sphere so my outer + + align:start position:0% +boundary of the sphere so my outer + + + align:start position:0% +boundary of the sphere so my outer +boundary for row is going to be this + + align:start position:0% +boundary for row is going to be this + + + align:start position:0% +boundary for row is going to be this +value it's going to be determined by + + align:start position:0% +value it's going to be determined by + + + align:start position:0% +value it's going to be determined by +Fe right and now I have to determine my + + align:start position:0% +Fe right and now I have to determine my + + + align:start position:0% +Fe right and now I have to determine my +inner boundary right and my inner + + align:start position:0% +inner boundary right and my inner + + + align:start position:0% +inner boundary right and my inner +boundary is actually quite simple it's a + + align:start position:0% +boundary is actually quite simple it's a + + + align:start position:0% +boundary is actually quite simple it's a +very simple geometric thing and so my + + align:start position:0% +very simple geometric thing and so my + + + align:start position:0% +very simple geometric thing and so my +inner boundary deals with the fact that + + align:start position:0% +inner boundary deals with the fact that + + + align:start position:0% +inner boundary deals with the fact that +if this is my plane Z equals 1 and I + + align:start position:0% +if this is my plane Z equals 1 and I + + + align:start position:0% +if this is my plane Z equals 1 and I +look at this triangle I make right + + align:start position:0% +look at this triangle I make right + + + align:start position:0% +look at this triangle I make right +here this this angle down here the + + align:start position:0% +here this this angle down here the + + + align:start position:0% +here this this angle down here the +bottom angle is Fe and this is a right + + align:start position:0% +bottom angle is Fe and this is a right + + + align:start position:0% +bottom angle is Fe and this is a right +angle and this is the row value I'm + + align:start position:0% +angle and this is the row value I'm + + + align:start position:0% +angle and this is the row value I'm +interested in is this hypotenuse right I + + align:start position:0% +interested in is this hypotenuse right I + + + align:start position:0% +interested in is this hypotenuse right I +need to figure out what the length of + + align:start position:0% +need to figure out what the length of + + + align:start position:0% +need to figure out what the length of +this is right here and you can see it + + align:start position:0% +this is right here and you can see it + + + align:start position:0% +this is right here and you can see it +right away from just the fact that this + + align:start position:0% +right away from just the fact that this + + + align:start position:0% +right away from just the fact that this +is Fe is is this little in this angle + + align:start position:0% +is Fe is is this little in this angle + + + align:start position:0% +is Fe is is this little in this angle +here you get Fe is secant sorry Fe row + + align:start position:0% +here you get Fe is secant sorry Fe row + + + align:start position:0% +here you get Fe is secant sorry Fe row +is secant Fe so the the bottom boundary + + align:start position:0% +is secant Fe so the the bottom boundary + + + align:start position:0% +is secant Fe so the the bottom boundary +comes from just simple geometry you get + + align:start position:0% +comes from just simple geometry you get + + + align:start position:0% +comes from just simple geometry you get +this length is one here so you get row + + align:start position:0% +this length is one here so you get row + + + align:start position:0% +this length is one here so you get row +is equal to secant Fe right this length + + align:start position:0% +is equal to secant Fe right this length + + + align:start position:0% +is equal to secant Fe right this length +here is one this is the row I'm + + align:start position:0% +here is one this is the row I'm + + + align:start position:0% +here is one this is the row I'm +interested in the blue part here so row + + align:start position:0% +interested in the blue part here so row + + + align:start position:0% +interested in the blue part here so row +is equal to secant Fe as the lower bound + + align:start position:0% +is equal to secant Fe as the lower bound + + + align:start position:0% +is equal to secant Fe as the lower bound +and it's equal to two cosine Fe as the + + align:start position:0% +and it's equal to two cosine Fe as the + + + align:start position:0% +and it's equal to two cosine Fe as the +upper bound okay and the thing I want to + + align:start position:0% +upper bound okay and the thing I want to + + + align:start position:0% +upper bound okay and the thing I want to +be careful of is I'm not supposed to + + align:start position:0% +be careful of is I'm not supposed to + + + align:start position:0% +be careful of is I'm not supposed to +include it won't matter for the integral + + align:start position:0% +include it won't matter for the integral + + + align:start position:0% +include it won't matter for the integral +but I'm not supposed to include the + + align:start position:0% +but I'm not supposed to include the + + + align:start position:0% +but I'm not supposed to include the +plane so row is going to be let me write + + align:start position:0% +plane so row is going to be let me write + + + align:start position:0% +plane so row is going to be let me write +this and make sure row is going to be + + align:start position:0% +this and make sure row is going to be + + + align:start position:0% +this and make sure row is going to be +greater than secant + + align:start position:0% +greater than secant + + + align:start position:0% +greater than secant +Fe and it's going to be less than or + + align:start position:0% +Fe and it's going to be less than or + + + align:start position:0% +Fe and it's going to be less than or +equal to 2 cosine Fe + + align:start position:0% + + + + align:start position:0% + +right right so let me double check and + + align:start position:0% +right right so let me double check and + + + align:start position:0% +right right so let me double check and +make sure I didn't make a geometry + + align:start position:0% +make sure I didn't make a geometry + + + align:start position:0% +make sure I didn't make a geometry +mistake here just to be sure this + + align:start position:0% +mistake here just to be sure this + + + align:start position:0% +mistake here just to be sure this +picture tells me that cosine Fe is equal + + align:start position:0% +picture tells me that cosine Fe is equal + + + align:start position:0% +picture tells me that cosine Fe is equal +to 1 over row that's good so row is + + align:start position:0% +to 1 over row that's good so row is + + + align:start position:0% +to 1 over row that's good so row is +equal to one over cosine Fe so I get + + align:start position:0% +equal to one over cosine Fe so I get + + + align:start position:0% +equal to one over cosine Fe so I get +secant fee there so my row values go all + + align:start position:0% +secant fee there so my row values go all + + + align:start position:0% +secant fee there so my row values go all +the way they start at the secant fee + + align:start position:0% +the way they start at the secant fee + + + align:start position:0% +the way they start at the secant fee +length and they go to the two cosine Fe + + align:start position:0% +length and they go to the two cosine Fe + + + align:start position:0% +length and they go to the two cosine Fe +length I know I maybe I'm beating a dead + + align:start position:0% +length I know I maybe I'm beating a dead + + + align:start position:0% +length I know I maybe I'm beating a dead +horse here but I want to make sure we + + align:start position:0% +horse here but I want to make sure we + + + align:start position:0% +horse here but I want to make sure we +understand where the row values are + + align:start position:0% +understand where the row values are + + + align:start position:0% +understand where the row values are +coming from so have all the bounds I + + align:start position:0% +coming from so have all the bounds I + + + align:start position:0% +coming from so have all the bounds I +need now I have the Theta bounds and I + + align:start position:0% +need now I have the Theta bounds and I + + + align:start position:0% +need now I have the Theta bounds and I +have the and the F bounds and the row + + align:start position:0% +have the and the F bounds and the row + + + align:start position:0% +have the and the F bounds and the row +bounds now you notice that Theta and Fe + + align:start position:0% +bounds now you notice that Theta and Fe + + + align:start position:0% +bounds now you notice that Theta and Fe +don't depend on uh don't depend on the + + align:start position:0% +don't depend on uh don't depend on the + + + align:start position:0% +don't depend on uh don't depend on the +other variables but row depends on Fe so + + align:start position:0% +other variables but row depends on Fe so + + + align:start position:0% +other variables but row depends on Fe so +we're going to have to integrate that + + align:start position:0% +we're going to have to integrate that + + + align:start position:0% +we're going to have to integrate that +first so now we can deal with Part + + align:start position:0% +first so now we can deal with Part + + + align:start position:0% +first so now we can deal with Part +B Part B let's come back over remind + + align:start position:0% +B Part B let's come back over remind + + + align:start position:0% +B Part B let's come back over remind +ourselves what it said it said set up + + align:start position:0% +ourselves what it said it said set up + + + align:start position:0% +ourselves what it said it said set up +the integral for the average distance of + + align:start position:0% +the integral for the average distance of + + + align:start position:0% +the integral for the average distance of +a point in D from the origin so I'm + + align:start position:0% +a point in D from the origin so I'm + + + align:start position:0% +a point in D from the origin so I'm +taking the average value of a function + + align:start position:0% +taking the average value of a function + + + align:start position:0% +taking the average value of a function +function what is that function I'm + + align:start position:0% +function what is that function I'm + + + align:start position:0% +function what is that function I'm +averaging how do I find the distance + + align:start position:0% +averaging how do I find the distance + + + align:start position:0% +averaging how do I find the distance +from the origin well the distance from + + align:start position:0% +from the origin well the distance from + + + align:start position:0% +from the origin well the distance from +the origin is a great function to have + + align:start position:0% +the origin is a great function to have + + + align:start position:0% +the origin is a great function to have +in spherical coordinates because it's + + align:start position:0% +in spherical coordinates because it's + + + align:start position:0% +in spherical coordinates because it's +just row so the function I'm supposed to + + align:start position:0% +just row so the function I'm supposed to + + + align:start position:0% +just row so the function I'm supposed to +average over is the function Row in + + align:start position:0% +average over is the function Row in + + + align:start position:0% +average over is the function Row in +spherical coordinates that's the + + align:start position:0% +spherical coordinates that's the + + + align:start position:0% +spherical coordinates that's the +function so let me write down what we're + + align:start position:0% +function so let me write down what we're + + + align:start position:0% +function so let me write down what we're +going to have here so Part + + align:start position:0% +going to have here so Part + + + align:start position:0% +going to have here so Part +B the average + + align:start position:0% + + + + align:start position:0% + +distance is going to equal well it's + + align:start position:0% +distance is going to equal well it's + + + align:start position:0% +distance is going to equal well it's +going to equal 1 / the volume of + + align:start position:0% +going to equal 1 / the volume of + + + align:start position:0% +going to equal 1 / the volume of +D times the triple integral over + + align:start position:0% +D times the triple integral over + + + align:start position:0% +D times the triple integral over +d right of the function + + align:start position:0% +d right of the function + + + align:start position:0% +d right of the function +row DV okay so now I have to write DV in + + align:start position:0% +row DV okay so now I have to write DV in + + + align:start position:0% +row DV okay so now I have to write DV in +the spherical coordinates and I have to + + align:start position:0% +the spherical coordinates and I have to + + + align:start position:0% +the spherical coordinates and I have to +write D in the spherical coordinate + + align:start position:0% +write D in the spherical coordinate + + + align:start position:0% +write D in the spherical coordinate +bounds and then I know I have to figure + + align:start position:0% +bounds and then I know I have to figure + + + align:start position:0% +bounds and then I know I have to figure +out the volume of D so we're going to + + align:start position:0% +out the volume of D so we're going to + + + align:start position:0% +out the volume of D so we're going to +figure out each of these things and then + + align:start position:0% +figure out each of these things and then + + + align:start position:0% +figure out each of these things and then +we'll be done all right so what is first + + align:start position:0% +we'll be done all right so what is first + + + align:start position:0% +we'll be done all right so what is first +what is the volume of D well the volume + + align:start position:0% +what is the volume of D well the volume + + + align:start position:0% +what is the volume of D well the volume +of D let's think about what it is it's + + align:start position:0% +of D let's think about what it is it's + + + align:start position:0% +of D let's think about what it is it's +it's a sphere of radius + + align:start position:0% +it's a sphere of radius + + + align:start position:0% +it's a sphere of radius +one and so the volume of a sphere of + + align:start position:0% +one and so the volume of a sphere of + + + align:start position:0% +one and so the volume of a sphere of +radius 1 is 4 4/3 pi R cubed and I want + + align:start position:0% +radius 1 is 4 4/3 pi R cubed and I want + + + align:start position:0% +radius 1 is 4 4/3 pi R cubed and I want +half of that so I want 2/3 since my + + align:start position:0% +half of that so I want 2/3 since my + + + align:start position:0% +half of that so I want 2/3 since my +radius is one I just have to do 2/3 Pi + + align:start position:0% +radius is one I just have to do 2/3 Pi + + + align:start position:0% +radius is one I just have to do 2/3 Pi +so I just the first part is 1 / 2/3 Pi + + align:start position:0% +so I just the first part is 1 / 2/3 Pi + + + align:start position:0% +so I just the first part is 1 / 2/3 Pi +that's the volume of a half sphere of + + align:start position:0% +that's the volume of a half sphere of + + + align:start position:0% +that's the volume of a half sphere of +radius one and now let's + + align:start position:0% +radius one and now let's + + + align:start position:0% +radius one and now let's +integrate + + align:start position:0% +integrate + + + align:start position:0% +integrate +so I'll leave a little space to write my + + align:start position:0% +so I'll leave a little space to write my + + + align:start position:0% +so I'll leave a little space to write my +bounds DV I'm going to write the bounds + + align:start position:0% +bounds DV I'm going to write the bounds + + + align:start position:0% +bounds DV I'm going to write the bounds +last after I have everything in order + + align:start position:0% +last after I have everything in order + + + align:start position:0% +last after I have everything in order +over here DV is row s sin Fe d r d Theta + + align:start position:0% +over here DV is row s sin Fe d r d Theta + + + align:start position:0% +over here DV is row s sin Fe d r d Theta +D Fe so I'm going to end up with a row + + align:start position:0% +D Fe so I'm going to end up with a row + + + align:start position:0% +D Fe so I'm going to end up with a row +cubed sin v d Row D Theta D + + align:start position:0% +cubed sin v d Row D Theta D + + + align:start position:0% +cubed sin v d Row D Theta D +Fe right the DV gave me an extra row + + align:start position:0% +Fe right the DV gave me an extra row + + + align:start position:0% +Fe right the DV gave me an extra row +squared and a sign Fe and then this + + align:start position:0% +squared and a sign Fe and then this + + + align:start position:0% +squared and a sign Fe and then this +these are the that that whole part is DV + + align:start position:0% +these are the that that whole part is DV + + + align:start position:0% +these are the that that whole part is DV +sorry and then I keep one row from the + + align:start position:0% +sorry and then I keep one row from the + + + align:start position:0% +sorry and then I keep one row from the +fact that the distance function is is + + align:start position:0% +fact that the distance function is is + + + align:start position:0% +fact that the distance function is is +row and so I get a row cubed there so + + align:start position:0% +row and so I get a row cubed there so + + + align:start position:0% +row and so I get a row cubed there so +hopefully that makes sense now D row I + + align:start position:0% +hopefully that makes sense now D row I + + + align:start position:0% +hopefully that makes sense now D row I +know the bounds are secant Fe to 2 + + align:start position:0% +know the bounds are secant Fe to 2 + + + align:start position:0% +know the bounds are secant Fe to 2 +cosine + + align:start position:0% +cosine + + + align:start position:0% +cosine +Fe D Theta my bounds are 0 to 2 pi and D + + align:start position:0% +Fe D Theta my bounds are 0 to 2 pi and D + + + align:start position:0% +Fe D Theta my bounds are 0 to 2 pi and D +Fe my bounds were 0 to Pi + + align:start position:0% +Fe my bounds were 0 to Pi + + + align:start position:0% +Fe my bounds were 0 to Pi +over4 and so that actually I didn't make + + align:start position:0% +over4 and so that actually I didn't make + + + align:start position:0% +over4 and so that actually I didn't make +you evaluate it I'm just making you set + + align:start position:0% +you evaluate it I'm just making you set + + + align:start position:0% +you evaluate it I'm just making you set +it up that actually is the solution we + + align:start position:0% +it up that actually is the solution we + + + align:start position:0% +it up that actually is the solution we +wanted for Part B I wanted to average + + align:start position:0% +wanted for Part B I wanted to average + + + align:start position:0% +wanted for Part B I wanted to average +the distance from any point in D to the + + align:start position:0% +the distance from any point in D to the + + + align:start position:0% +the distance from any point in D to the +origin so I just took the average value + + align:start position:0% +origin so I just took the average value + + + align:start position:0% +origin so I just took the average value +of the function row over that region D + + align:start position:0% +of the function row over that region D + + + align:start position:0% +of the function row over that region D +and so that's how you finish that up so + + align:start position:0% +and so that's how you finish that up so + + + align:start position:0% +and so that's how you finish that up so +this problem basically we want you to + + align:start position:0% +this problem basically we want you to + + + align:start position:0% +this problem basically we want you to +get really familiar with how to do some + + align:start position:0% +get really familiar with how to do some + + + align:start position:0% +get really familiar with how to do some +things in in these spherical coordinates + + align:start position:0% +things in in these spherical coordinates + + + align:start position:0% +things in in these spherical coordinates +which are sometimes a little hard to do + + align:start position:0% +which are sometimes a little hard to do + + + align:start position:0% +which are sometimes a little hard to do +but if you notice what we were doing and + + align:start position:0% +but if you notice what we were doing and + + + align:start position:0% +but if you notice what we were doing and +trying to figure F out the bounds in + + align:start position:0% +trying to figure F out the bounds in + + + align:start position:0% +trying to figure F out the bounds in +particular trying to figure out row we + + align:start position:0% +particular trying to figure out row we + + + align:start position:0% +particular trying to figure out row we +took what we knew in the XYZ coordinates + + align:start position:0% +took what we knew in the XYZ coordinates + + + align:start position:0% +took what we knew in the XYZ coordinates +about certain relationships and then we + + align:start position:0% +about certain relationships and then we + + + align:start position:0% +about certain relationships and then we +we replace the XYZ values by the values + + align:start position:0% +we replace the XYZ values by the values + + + align:start position:0% +we replace the XYZ values by the values +in terms of row and and Theta and Fe and + + align:start position:0% +in terms of row and and Theta and Fe and + + + align:start position:0% +in terms of row and and Theta and Fe and +you can simplify to figure out the + + align:start position:0% +you can simplify to figure out the + + + align:start position:0% +you can simplify to figure out the +relationships you have between row and + + align:start position:0% +relationships you have between row and + + + align:start position:0% +relationships you have between row and +Theta and Fe for say the boundary value + + align:start position:0% +Theta and Fe for say the boundary value + + + align:start position:0% +Theta and Fe for say the boundary value +so that was kind of one of the + + align:start position:0% +so that was kind of one of the + + + align:start position:0% +so that was kind of one of the +techniques we were using there and + + align:start position:0% +techniques we were using there and + + + align:start position:0% +techniques we were using there and +hopefully the geometric understanding of + + align:start position:0% +hopefully the geometric understanding of + + + align:start position:0% +hopefully the geometric understanding of +why these angles go from 0 to 2 pi and 0 + + align:start position:0% +why these angles go from 0 to 2 pi and 0 + + + align:start position:0% +why these angles go from 0 to 2 pi and 0 +to pi over 4 is clear and actually this + + align:start position:0% +to pi over 4 is clear and actually this + + + align:start position:0% +to pi over 4 is clear and actually this +should remind you the fact that this is + + align:start position:0% +should remind you the fact that this is + + + align:start position:0% +should remind you the fact that this is +row equal 2 cosine Fe should remind you + + align:start position:0% +row equal 2 cosine Fe should remind you + + + align:start position:0% +row equal 2 cosine Fe should remind you +of the two dimensional case where you + + align:start position:0% +of the two dimensional case where you + + + align:start position:0% +of the two dimensional case where you +had some problem like R equals 2 cosine + + align:start position:0% +had some problem like R equals 2 cosine + + + align:start position:0% +had some problem like R equals 2 cosine +Theta and that Drew a circle off center + + align:start position:0% +Theta and that Drew a circle off center + + + align:start position:0% +Theta and that Drew a circle off center +from the origin it's the same it's the + + align:start position:0% +from the origin it's the same it's the + + + align:start position:0% +from the origin it's the same it's the +analogous kind of thing happening here + + align:start position:0% +analogous kind of thing happening here + + + align:start position:0% +analogous kind of thing happening here +so maybe I should stop there before I + + align:start position:0% +so maybe I should stop there before I + + + align:start position:0% +so maybe I should stop there before I +say too many things but the again the + + align:start position:0% +say too many things but the again the + + + align:start position:0% +say too many things but the again the +object of this was just to get really + + align:start position:0% +object of this was just to get really + + + align:start position:0% +object of this was just to get really +comfortable with spherical coordinates + + align:start position:0% +comfortable with spherical coordinates + + + align:start position:0% +comfortable with spherical coordinates +and I hope it's helped you I'll stop + + align:start position:0% +and I hope it's helped you I'll stop + + + align:start position:0% +and I hope it's helped you I'll stop +there \ No newline at end of file diff --git a/RpeaxINv2Yk.txt b/RpeaxINv2Yk.txt new file mode 100644 index 0000000000000000000000000000000000000000..7a4db0075dff6346d488d89474eeb0c440af3f3c --- /dev/null +++ b/RpeaxINv2Yk.txt @@ -0,0 +1,9963 @@ +align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +um so I've written up on the board as + + align:start position:0% +um so I've written up on the board as + + + align:start position:0% +um so I've written up on the board as +usual the topics uh or some of the main + + align:start position:0% +usual the topics uh or some of the main + + + align:start position:0% +usual the topics uh or some of the main +topics uh for this lecture uh it it + + align:start position:0% +topics uh for this lecture uh it it + + + align:start position:0% +topics uh for this lecture uh it it +certainly will connect to the next one + + align:start position:0% +certainly will connect to the next one + + + align:start position:0% +certainly will connect to the next one +uh so this is uh least squares + + align:start position:0% +uh so this is uh least squares + + + align:start position:0% +uh so this is uh least squares +estimation and uh uh so I'm interested + + align:start position:0% +estimation and uh uh so I'm interested + + + align:start position:0% +estimation and uh uh so I'm interested +here in waiting in the waiting Matrix + + align:start position:0% +here in waiting in the waiting Matrix + + + align:start position:0% +here in waiting in the waiting Matrix +the the role of The covariance Matrix + + align:start position:0% +the the role of The covariance Matrix + + + align:start position:0% +the the role of The covariance Matrix +and in the recursive + + align:start position:0% +and in the recursive + + + align:start position:0% +and in the recursive +part uh but + + align:start position:0% +part uh but + + + align:start position:0% +part uh but +the number of parameters the parameters + + align:start position:0% +the number of parameters the parameters + + + align:start position:0% +the number of parameters the parameters +I'm looking for you hat well I'm looking + + align:start position:0% +I'm looking for you hat well I'm looking + + + align:start position:0% +I'm looking for you hat well I'm looking +for you and I settle for you + + align:start position:0% +for you and I settle for you + + + align:start position:0% +for you and I settle for you +hat is not changing I mean it's is + + align:start position:0% +hat is not changing I mean it's is + + + align:start position:0% +hat is not changing I mean it's is +improving but but uh + + align:start position:0% +improving but but uh + + + align:start position:0% +improving but but uh +we're we're at a fixed time so to speak + + align:start position:0% +we're we're at a fixed time so to speak + + + align:start position:0% +we're we're at a fixed time so to speak +so we've got these various steps Le + + align:start position:0% +so we've got these various steps Le + + + align:start position:0% +so we've got these various steps Le +squares hi I I think I started a moment + + align:start position:0% +squares hi I I think I started a moment + + + align:start position:0% +squares hi I I think I started a moment +early but I've written I haven't + + align:start position:0% +early but I've written I haven't + + + align:start position:0% +early but I've written I haven't +said anything yet that isn't already + + align:start position:0% +said anything yet that isn't already + + + align:start position:0% +said anything yet that isn't already +written um so this we know + + align:start position:0% +written um so this we know + + + align:start position:0% +written um so this we know +about this this this waiting Matrix I'll + + align:start position:0% +about this this this waiting Matrix I'll + + + align:start position:0% +about this this this waiting Matrix I'll +introduce early and then this recursive + + align:start position:0% +introduce early and then this recursive + + + align:start position:0% +introduce early and then this recursive +aspect so that's the those are the + + align:start position:0% +aspect so that's the those are the + + + align:start position:0% +aspect so that's the those are the +themes of this lecture and then uh on + + align:start position:0% +themes of this lecture and then uh on + + + align:start position:0% +themes of this lecture and then uh on +into the next lecture we'll come a + + align:start position:0% +into the next lecture we'll come a + + + align:start position:0% +into the next lecture we'll come a +dynamic problem in which the U that + + align:start position:0% +dynamic problem in which the U that + + + align:start position:0% +dynamic problem in which the U that +we're looking for is + + align:start position:0% +we're looking for is + + + align:start position:0% +we're looking for is +changing so you know something is moving + + align:start position:0% +changing so you know something is moving + + + align:start position:0% +changing so you know something is moving +we're tracking uh uh a missile whatever + + align:start position:0% +we're tracking uh uh a missile whatever + + + align:start position:0% +we're tracking uh uh a missile whatever +we're doing the the we know something + + align:start position:0% +we're doing the the we know something + + + align:start position:0% +we're doing the the we know something +about the connection between the present + + align:start position:0% +about the connection between the present + + + align:start position:0% +about the connection between the present +State and the previous state but they're + + align:start position:0% +State and the previous state but they're + + + align:start position:0% +State and the previous state but they're +not the same okay and may I say I regret + + align:start position:0% +not the same okay and may I say I regret + + + align:start position:0% +not the same okay and may I say I regret +that kalman's name starts with k because + + align:start position:0% +that kalman's name starts with k because + + + align:start position:0% +that kalman's name starts with k because +I've been using K so widely for uh our a + + align:start position:0% +I've been using K so widely for uh our a + + + align:start position:0% +I've been using K so widely for uh our a +transpose CA Matrix but maybe uh today + + align:start position:0% +transpose CA Matrix but maybe uh today + + + align:start position:0% +transpose CA Matrix but maybe uh today +uh I'll tend to write out a transpose CA + + align:start position:0% +uh I'll tend to write out a transpose CA + + + align:start position:0% +uh I'll tend to write out a transpose CA +or a transpose Sigma inverse a that will + + align:start position:0% +or a transpose Sigma inverse a that will + + + align:start position:0% +or a transpose Sigma inverse a that will +be the Matrix C that's appropriate so + + align:start position:0% +be the Matrix C that's appropriate so + + + align:start position:0% +be the Matrix C that's appropriate so +I'll I'll stay with the of course the + + align:start position:0% +I'll I'll stay with the of course the + + + align:start position:0% +I'll I'll stay with the of course the +world convention that K stands for the + + align:start position:0% +world convention that K stands for the + + + align:start position:0% +world convention that K stands for the +this uh gain Matrix named after + + align:start position:0% +this uh gain Matrix named after + + + align:start position:0% +this uh gain Matrix named after +calman and uh and + + align:start position:0% + + + + align:start position:0% + +I'll uh + + align:start position:0% +I'll uh + + + align:start position:0% +I'll uh +come to that maybe can I say just a few + + align:start position:0% +come to that maybe can I say just a few + + + align:start position:0% +come to that maybe can I say just a few +words in advance before I + + align:start position:0% +words in advance before I + + + align:start position:0% +words in advance before I +start um well one I I want to say a few + + align:start position:0% +start um well one I I want to say a few + + + align:start position:0% +start um well one I I want to say a few +final things about the + + align:start position:0% +final things about the + + + align:start position:0% +final things about the +SVD or maybe not final but a few just a + + align:start position:0% +SVD or maybe not final but a few just a + + + align:start position:0% +SVD or maybe not final but a few just a +supplementary like a short recap partly + + align:start position:0% +supplementary like a short recap partly + + + align:start position:0% +supplementary like a short recap partly +because I feel it's always good to for + + align:start position:0% +because I feel it's always good to for + + + align:start position:0% +because I feel it's always good to for +the previous lecture to kind of get come + + align:start position:0% +the previous lecture to kind of get come + + + align:start position:0% +the previous lecture to kind of get come +back again uh uh at the start uh + + align:start position:0% +back again uh uh at the start uh + + + align:start position:0% +back again uh uh at the start uh +um secondly to say that this + + align:start position:0% +um secondly to say that this + + + align:start position:0% +um secondly to say that this +area is um well first to say that I'm + + align:start position:0% +area is um well first to say that I'm + + + align:start position:0% +area is um well first to say that I'm +not an expert in it and that I had a + + align:start position:0% +not an expert in it and that I had a + + + align:start position:0% +not an expert in it and that I had a +wild time this morning uh I feel I left + + align:start position:0% +wild time this morning uh I feel I left + + + align:start position:0% +wild time this morning uh I feel I left +home with a head packed full of formulas + + align:start position:0% +home with a head packed full of formulas + + + align:start position:0% +home with a head packed full of formulas +from for the calman filter and + + align:start position:0% +from for the calman filter and + + + align:start position:0% +from for the calman filter and +um uh but one and the formulas are quite + + align:start position:0% +um uh but one and the formulas are quite + + + align:start position:0% +um uh but one and the formulas are quite +wonderful uh and I'll try to organize + + align:start position:0% +wonderful uh and I'll try to organize + + + align:start position:0% +wonderful uh and I'll try to organize +them here but I just have to say that uh + + align:start position:0% +them here but I just have to say that uh + + + align:start position:0% +them here but I just have to say that uh +every exposition of the calman filter + + align:start position:0% +every exposition of the calman filter + + + align:start position:0% +every exposition of the calman filter +has its own way of reaching these + + align:start position:0% +has its own way of reaching these + + + align:start position:0% +has its own way of reaching these +formulas and they always seem + + align:start position:0% +formulas and they always seem + + + align:start position:0% +formulas and they always seem +confusing uh and then the next person + + align:start position:0% +confusing uh and then the next person + + + align:start position:0% +confusing uh and then the next person +tries his his or her own way and feels + + align:start position:0% +tries his his or her own way and feels + + + align:start position:0% +tries his his or her own way and feels +okay now I've finally got it all clear + + align:start position:0% +okay now I've finally got it all clear + + + align:start position:0% +okay now I've finally got it all clear +but of course the next reader says not + + align:start position:0% +but of course the next reader says not + + + align:start position:0% +but of course the next reader says not +the best way and do it again so that + + align:start position:0% +the best way and do it again so that + + + align:start position:0% +the best way and do it again so that +applies uh to myself too um so there's + + align:start position:0% +applies uh to myself too um so there's + + + align:start position:0% +applies uh to myself too um so there's +not uh there's a just a little about the + + align:start position:0% +not uh there's a just a little about the + + + align:start position:0% +not uh there's a just a little about the +calman filter in the course textbook the + + align:start position:0% +calman filter in the course textbook the + + + align:start position:0% +calman filter in the course textbook the +applied math book uh then the latest + + align:start position:0% +applied math book uh then the latest + + + align:start position:0% +applied math book uh then the latest +book that I got involved with was about + + align:start position:0% +book that I got involved with was about + + + align:start position:0% +book that I got involved with was about +um was this one with my friend Kai Bor + + align:start position:0% +um was this one with my friend Kai Bor + + + align:start position:0% +um was this one with my friend Kai Bor +uh it starts with linear algebra so that + + align:start position:0% +uh it starts with linear algebra so that + + + align:start position:0% +uh it starts with linear algebra so that +those chapters are very familiar his + + align:start position:0% +those chapters are very familiar his + + + align:start position:0% +those chapters are very familiar his +subject is geodyssey and then the third + + align:start position:0% +subject is geodyssey and then the third + + + align:start position:0% +subject is geodyssey and then the third +part of of the book is about GPS global + + align:start position:0% +part of of the book is about GPS global + + + align:start position:0% +part of of the book is about GPS global +positioning well for that filtering is + + align:start position:0% +positioning well for that filtering is + + + align:start position:0% +positioning well for that filtering is +all is highly important so had to learn + + align:start position:0% +all is highly important so had to learn + + + align:start position:0% +all is highly important so had to learn +about the calman filter and the final + + align:start position:0% +about the calman filter and the final + + + align:start position:0% +about the calman filter and the final +chapter of that book is now or will be + + align:start position:0% +chapter of that book is now or will be + + + align:start position:0% +chapter of that book is now or will be +this afternoon or early tomorrow morning + + align:start position:0% +this afternoon or early tomorrow morning + + + align:start position:0% +this afternoon or early tomorrow morning +on our website so I felt I wanted to + + align:start position:0% +on our website so I felt I wanted to + + + align:start position:0% +on our website so I felt I wanted to +give you + + align:start position:0% +give you + + + align:start position:0% +give you +uh since we couldn't get all the the + + align:start position:0% +uh since we couldn't get all the the + + + align:start position:0% +uh since we couldn't get all the the +board isn't big enough for all the + + align:start position:0% +board isn't big enough for all the + + + align:start position:0% +board isn't big enough for all the +formulas of of the calman filter but + + align:start position:0% +formulas of of the calman filter but + + + align:start position:0% +formulas of of the calman filter but +uh so that's this chapter 17 cman + + align:start position:0% +uh so that's this chapter 17 cman + + + align:start position:0% +uh so that's this chapter 17 cman +filters from that book is on the + + align:start position:0% +filters from that book is on the + + + align:start position:0% +filters from that book is on the +website and and really uh expresses + + align:start position:0% +website and and really uh expresses + + + align:start position:0% +website and and really uh expresses +my uh starting + + align:start position:0% +my uh starting + + + align:start position:0% +my uh starting +point so what should I say about that + + align:start position:0% +point so what should I say about that + + + align:start position:0% +point so what should I say about that +and I say it here uh there are several + + align:start position:0% +and I say it here uh there are several + + + align:start position:0% +and I say it here uh there are several +ways to start on the calman filter + + align:start position:0% +ways to start on the calman filter + + + align:start position:0% +ways to start on the calman filter +people who are in statistics think of it + + align:start position:0% +people who are in statistics think of it + + + align:start position:0% +people who are in statistics think of it +as regression + + align:start position:0% +as regression + + + align:start position:0% +as regression +people who are in probability think of + + align:start position:0% +people who are in probability think of + + + align:start position:0% +people who are in probability think of +it as Contin conditional probability and + + align:start position:0% +it as Contin conditional probability and + + + align:start position:0% +it as Contin conditional probability and +those + + align:start position:0% +those + + + align:start position:0% +those +two which from a distance seem like they + + align:start position:0% +two which from a distance seem like they + + + align:start position:0% +two which from a distance seem like they +should be able to talk to each other uh + + align:start position:0% +should be able to talk to each other uh + + + align:start position:0% +should be able to talk to each other uh +I can see in the early literature many + + align:start position:0% +I can see in the early literature many + + + align:start position:0% +I can see in the early literature many +references to people + + align:start position:0% +references to people + + + align:start position:0% +references to people +who had to translate of course the main + + align:start position:0% +who had to translate of course the main + + + align:start position:0% +who had to translate of course the main +ideas into their own world so that all + + align:start position:0% +ideas into their own world so that all + + + align:start position:0% +ideas into their own world so that all +these different worlds are + + align:start position:0% +these different worlds are + + + align:start position:0% +these different worlds are +represented um and uh you're everybody + + align:start position:0% +represented um and uh you're everybody + + + align:start position:0% +represented um and uh you're everybody +all of us have different backgrounds uh + + align:start position:0% +all of us have different backgrounds uh + + + align:start position:0% +all of us have different backgrounds uh +so that's one reference sort of from + + align:start position:0% +so that's one reference sort of from + + + align:start position:0% +so that's one reference sort of from +this course and of course my point of + + align:start position:0% +this course and of course my point of + + + align:start position:0% +this course and of course my point of +view is because I don't know the other + + align:start position:0% +view is because I don't know the other + + + align:start position:0% +view is because I don't know the other +stuff well enough + + align:start position:0% +stuff well enough + + + align:start position:0% +stuff well enough +is matrices linear algebra I look at + + align:start position:0% +is matrices linear algebra I look at + + + align:start position:0% +is matrices linear algebra I look at +these as Pro I'll so I'll just look at + + align:start position:0% +these as Pro I'll so I'll just look at + + + align:start position:0% +these as Pro I'll so I'll just look at +these as problems in linear algebra + + align:start position:0% +these as problems in linear algebra + + + align:start position:0% +these as problems in linear algebra +we're looking for that solution you hat + + align:start position:0% +we're looking for that solution you hat + + + align:start position:0% +we're looking for that solution you hat +and new data comes in and we looking for + + align:start position:0% +and new data comes in and we looking for + + + align:start position:0% +and new data comes in and we looking for +the change so we we have a uat old from + + align:start position:0% +the change so we we have a uat old from + + + align:start position:0% +the change so we we have a uat old from +from the from an original set of data + + align:start position:0% +from the from an original set of data + + + align:start position:0% +from the from an original set of data +some new B new comes in I have to update + + align:start position:0% +some new B new comes in I have to update + + + align:start position:0% +some new B new comes in I have to update +it and uh I'm looking for the + + align:start position:0% +it and uh I'm looking for the + + + align:start position:0% +it and uh I'm looking for the +formula so that will be uh sort of + + align:start position:0% +formula so that will be uh sort of + + + align:start position:0% +formula so that will be uh sort of +straightforward matrices I I guess I'm + + align:start position:0% +straightforward matrices I I guess I'm + + + align:start position:0% +straightforward matrices I I guess I'm +hoping that that that's a language that + + align:start position:0% +hoping that that that's a language that + + + align:start position:0% +hoping that that that's a language that +almost everybody + + align:start position:0% +almost everybody + + + align:start position:0% +almost everybody +speaks I hope I mean it's least it's + + align:start position:0% +speaks I hope I mean it's least it's + + + align:start position:0% +speaks I hope I mean it's least it's +like more + + align:start position:0% +like more + + + align:start position:0% +like more +uh it's not Esperanto maybe but it's uh + + align:start position:0% +uh it's not Esperanto maybe but it's uh + + + align:start position:0% +uh it's not Esperanto maybe but it's uh +it's um + + align:start position:0% +it's um + + + align:start position:0% +it's um +uh sort of you don't need to be a + + align:start position:0% +uh sort of you don't need to be a + + + align:start position:0% +uh sort of you don't need to be a +specialist in in these areas to to deal + + align:start position:0% +specialist in in these areas to to deal + + + align:start position:0% +specialist in in these areas to to deal +with the Matrix formulas but I have to + + align:start position:0% +with the Matrix formulas but I have to + + + align:start position:0% +with the Matrix formulas but I have to +admit + + align:start position:0% +admit + + + align:start position:0% +admit +that once I see those formulas or once + + align:start position:0% +that once I see those formulas or once + + + align:start position:0% +that once I see those formulas or once +we see them we can figure them out by + + align:start position:0% +we see them we can figure them out by + + + align:start position:0% +we see them we can figure them out by +regular Matrix methods there's one + + align:start position:0% +regular Matrix methods there's one + + + align:start position:0% +regular Matrix methods there's one +identity one Matrix identity that's that + + align:start position:0% +identity one Matrix identity that's that + + + align:start position:0% +identity one Matrix identity that's that +I've mentioned before and now it's going + + align:start position:0% +I've mentioned before and now it's going + + + align:start position:0% +I've mentioned before and now it's going +to come into its own as the most + + align:start position:0% +to come into its own as the most + + + align:start position:0% +to come into its own as the most +important identity of and least and sort + + align:start position:0% +important identity of and least and sort + + + align:start position:0% +important identity of and least and sort +of most important non-obvious Matrix + + align:start position:0% +of most important non-obvious Matrix + + + align:start position:0% +of most important non-obvious Matrix +identity in the world and uh so that's + + align:start position:0% +identity in the world and uh so that's + + + align:start position:0% +identity in the world and uh so that's +what'll get used um + + align:start position:0% +what'll get used um + + + align:start position:0% +what'll get used um +but if I if if these other people who + + align:start position:0% +but if I if if these other people who + + + align:start position:0% +but if I if if these other people who +knew the who knew the other other the + + align:start position:0% +knew the who knew the other other the + + + align:start position:0% +knew the who knew the other other the +the different ways to look at it hadn't + + align:start position:0% +the different ways to look at it hadn't + + + align:start position:0% +the different ways to look at it hadn't +derived if calman hadn't derived the + + align:start position:0% +derived if calman hadn't derived the + + + align:start position:0% +derived if calman hadn't derived the +calman formulas + + align:start position:0% +calman formulas + + + align:start position:0% +calman formulas +I have to admit I wouldn't + + align:start position:0% +I have to admit I wouldn't + + + align:start position:0% +I have to admit I wouldn't +have been able to to get to them uh so + + align:start position:0% +have been able to to get to them uh so + + + align:start position:0% +have been able to to get to them uh so +it's sort of those so those insights are + + align:start position:0% +it's sort of those so those insights are + + + align:start position:0% +it's sort of those so those insights are +are crucial uh I and so I should mention + + align:start position:0% +are crucial uh I and so I should mention + + + align:start position:0% +are crucial uh I and so I should mention +some authors and you'll know others uh + + align:start position:0% +some authors and you'll know others uh + + + align:start position:0% +some authors and you'll know others uh +one recent book that's I think + + align:start position:0% +one recent book that's I think + + + align:start position:0% +one recent book that's I think +especially + + align:start position:0% +especially + + + align:start position:0% +especially +clear uh is by Brown and hang can I just + + align:start position:0% +clear uh is by Brown and hang can I just + + + align:start position:0% +clear uh is by Brown and hang can I just +I'll just maybe put these over here uh + + align:start position:0% +I'll just maybe put these over here uh + + + align:start position:0% +I'll just maybe put these over here uh +Brown and hang + + align:start position:0% + + + + align:start position:0% + +and it has the words calman applied + + align:start position:0% +and it has the words calman applied + + + align:start position:0% +and it has the words calman applied +calman filtering in the title an earlier + + align:start position:0% +calman filtering in the title an earlier + + + align:start position:0% +calman filtering in the title an earlier +book + + align:start position:0% +book + + + align:start position:0% +book +that was edited by + + align:start position:0% +that was edited by + + + align:start position:0% +that was edited by +gilb and came from uh uh uh + + align:start position:0% +gilb and came from uh uh uh + + + align:start position:0% +gilb and came from uh uh uh +nearby uh is is also uh highly + + align:start position:0% +nearby uh is is also uh highly + + + align:start position:0% +nearby uh is is also uh highly +recommended and I always + + align:start position:0% +recommended and I always + + + align:start position:0% +recommended and I always +enjoy uh the writing of Tom kyth + + align:start position:0% +enjoy uh the writing of Tom kyth + + + align:start position:0% +enjoy uh the writing of Tom kyth +uh who has a number of + + align:start position:0% +uh who has a number of + + + align:start position:0% +uh who has a number of +books uh about uh calman filters in fact + + align:start position:0% +books uh about uh calman filters in fact + + + align:start position:0% +books uh about uh calman filters in fact +I think a couple of new ones and here's + + align:start position:0% +I think a couple of new ones and here's + + + align:start position:0% +I think a couple of new ones and here's +a very old one lectures on weer and cman + + align:start position:0% +a very old one lectures on weer and cman + + + align:start position:0% +a very old one lectures on weer and cman +filtering so I didn't know what weiner + + align:start position:0% +filtering so I didn't know what weiner + + + align:start position:0% +filtering so I didn't know what weiner +filtering is was either is either but uh + + align:start position:0% +filtering is was either is either but uh + + + align:start position:0% +filtering is was either is either but uh +it's the lots of insights in Kyla's book + + align:start position:0% +it's the lots of insights in Kyla's book + + + align:start position:0% +it's the lots of insights in Kyla's book +Lots so those are a few of the + + align:start position:0% +Lots so those are a few of the + + + align:start position:0% +Lots so those are a few of the +possibilities um okay so that's some + + align:start position:0% +possibilities um okay so that's some + + + align:start position:0% +possibilities um okay so that's some +comments about books very + + align:start position:0% +comments about books very + + + align:start position:0% +comments about books very +incomplete uh and uh I'm happy to know + + align:start position:0% +incomplete uh and uh I'm happy to know + + + align:start position:0% +incomplete uh and uh I'm happy to know +of others always I'm I'm beginning to + + align:start position:0% +of others always I'm I'm beginning to + + + align:start position:0% +of others always I'm I'm beginning to +get emails of All Sorts now from you and + + align:start position:0% +get emails of All Sorts now from you and + + + align:start position:0% +get emails of All Sorts now from you and +I'm really appreciating it uh on on + + align:start position:0% +I'm really appreciating it uh on on + + + align:start position:0% +I'm really appreciating it uh on on +topics and on applications for example + + align:start position:0% +topics and on applications for example + + + align:start position:0% +topics and on applications for example +one application that I'd like to follow + + align:start position:0% +one application that I'd like to follow + + + align:start position:0% +one application that I'd like to follow +up that's been significant at lincol lab + + align:start position:0% +up that's been significant at lincol lab + + + align:start position:0% +up that's been significant at lincol lab +uh Bob Nichols got me uh connected a + + align:start position:0% +uh Bob Nichols got me uh connected a + + + align:start position:0% +uh Bob Nichols got me uh connected a +little bit is this St AP the stap um um + + align:start position:0% +little bit is this St AP the stap um um + + + align:start position:0% +little bit is this St AP the stap um um +and so I'm starting with an article from + + align:start position:0% +and so I'm starting with an article from + + + align:start position:0% +and so I'm starting with an article from +Lincoln lab uh journal and what is what + + align:start position:0% +Lincoln lab uh journal and what is what + + + align:start position:0% +Lincoln lab uh journal and what is what +was the key issue in that article it's + + align:start position:0% +was the key issue in that article it's + + + align:start position:0% +was the key issue in that article it's +exactly what we talked about last time + + align:start position:0% +exactly what we talked about last time + + + align:start position:0% +exactly what we talked about last time +we the the uh samples so so this is part + + align:start position:0% +we the the uh samples so so this is part + + + align:start position:0% +we the the uh samples so so this is part +of the recap then this is a recap of the + + align:start position:0% +of the recap then this is a recap of the + + + align:start position:0% +of the recap then this is a recap of the +QR part of the of last time uh in Janice + + align:start position:0% +QR part of the of last time uh in Janice + + + align:start position:0% +QR part of the of last time uh in Janice +McMahon + + align:start position:0% +McMahon + + + align:start position:0% +McMahon +um uh very nicely written paper on step + + align:start position:0% +um uh very nicely written paper on step + + + align:start position:0% +um uh very nicely written paper on step +she's the the central problem is to deal + + align:start position:0% +she's the the central problem is to deal + + + align:start position:0% +she's the the central problem is to deal +with uh to solve a linear system where + + align:start position:0% +with uh to solve a linear system where + + + align:start position:0% +with uh to solve a linear system where +the um coefficient Matrix let's call it + + align:start position:0% +the um coefficient Matrix let's call it + + + align:start position:0% +the um coefficient Matrix let's call it +R to follow her is comes from taking + + align:start position:0% +R to follow her is comes from taking + + + align:start position:0% +R to follow her is comes from taking +many + + align:start position:0% +many + + + align:start position:0% +many +samples so this was this is the + + align:start position:0% +samples so this was this is the + + + align:start position:0% +samples so this was this is the +coefficient Matrix uh the sample Matrix + + align:start position:0% +coefficient Matrix uh the sample Matrix + + + align:start position:0% +coefficient Matrix uh the sample Matrix +you could say coming from by taking many + + align:start position:0% +you could say coming from by taking many + + + align:start position:0% +you could say coming from by taking many +samples of uh from from radar uh data uh + + align:start position:0% +samples of uh from from radar uh data uh + + + align:start position:0% +samples of uh from from radar uh data uh +at different frequencies uh different + + align:start position:0% +at different frequencies uh different + + + align:start position:0% +at different frequencies uh different +Doppler uh Lots uh so X is a very long + + align:start position:0% +Doppler uh Lots uh so X is a very long + + + align:start position:0% +Doppler uh Lots uh so X is a very long +Vector this is probably a full Matrix + + align:start position:0% +Vector this is probably a full Matrix + + + align:start position:0% +Vector this is probably a full Matrix +and what she concludes + + align:start position:0% +and what she concludes + + + align:start position:0% +and what she concludes +is that to use uh + + align:start position:0% +is that to use uh + + + align:start position:0% +is that to use uh +orthogonalization in parallel is uh and + + align:start position:0% +orthogonalization in parallel is uh and + + + align:start position:0% +orthogonalization in parallel is uh and +and using heavy uh Computing of course + + align:start position:0% +and using heavy uh Computing of course + + + align:start position:0% +and using heavy uh Computing of course +is a way to go I'm going to hope to meet + + align:start position:0% +is a way to go I'm going to hope to meet + + + align:start position:0% +is a way to go I'm going to hope to meet +with her and speak more about that can I + + align:start position:0% +with her and speak more about that can I + + + align:start position:0% +with her and speak more about that can I +also just so that was that's just a + + align:start position:0% +also just so that was that's just a + + + align:start position:0% +also just so that was that's just a +touch of what I hope to come back to and + + align:start position:0% +touch of what I hope to come back to and + + + align:start position:0% +touch of what I hope to come back to and +can I also just recap one little point + + align:start position:0% +can I also just recap one little point + + + align:start position:0% +can I also just recap one little point +about one recap the SVD just to say + + align:start position:0% +about one recap the SVD just to say + + + align:start position:0% +about one recap the SVD just to say +again what it tells us just most + + align:start position:0% +again what it tells us just most + + + align:start position:0% +again what it tells us just most +directly so it say the most direct of of + + align:start position:0% +directly so it say the most direct of of + + + align:start position:0% +directly so it say the most direct of of +of the + + align:start position:0% +of the + + + align:start position:0% +of the +of this factorization U times Sigma + + align:start position:0% +of this factorization U times Sigma + + + align:start position:0% +of this factorization U times Sigma +different totally different Sigma oh boy + + align:start position:0% +different totally different Sigma oh boy + + + align:start position:0% +different totally different Sigma oh boy +we applied math is running out of + + align:start position:0% +we applied math is running out of + + + align:start position:0% +we applied math is running out of +letters even help with help from the + + align:start position:0% +letters even help with help from the + + + align:start position:0% +letters even help with help from the +Greeks uh this Sigma of course is so + + align:start position:0% +Greeks uh this Sigma of course is so + + + align:start position:0% +Greeks uh this Sigma of course is so +this + + align:start position:0% +this + + + align:start position:0% +this +is uh the orthogonal I vectors of uh AA + + align:start position:0% +is uh the orthogonal I vectors of uh AA + + + align:start position:0% +is uh the orthogonal I vectors of uh AA +transpose then these they're not I Val + + align:start position:0% +transpose then these they're not I Val + + + align:start position:0% +transpose then these they're not I Val +values they're singular values and then + + align:start position:0% +values they're singular values and then + + + align:start position:0% +values they're singular values and then +with a lot of + + align:start position:0% +with a lot of + + + align:start position:0% +with a lot of +zeros and then the orthogonal Lan + + align:start position:0% +zeros and then the orthogonal Lan + + + align:start position:0% +zeros and then the orthogonal Lan +vectors of a transpose + + align:start position:0% +vectors of a transpose + + + align:start position:0% +vectors of a transpose +a so maybe they're n of those and M of + + align:start position:0% +a so maybe they're n of those and M of + + + align:start position:0% +a so maybe they're n of those and M of +those if it's uh M byn Matrix and R here + + align:start position:0% +those if it's uh M byn Matrix and R here + + + align:start position:0% +those if it's uh M byn Matrix and R here +is the rank of the of the Matrix the + + align:start position:0% +is the rank of the of the Matrix the + + + align:start position:0% +is the rank of the of the Matrix the +number of uh so the number of + + align:start position:0% +number of uh so the number of + + + align:start position:0% +number of uh so the number of +nonzero igen values of a transpose a the + + align:start position:0% +nonzero igen values of a transpose a the + + + align:start position:0% +nonzero igen values of a transpose a the +number of independent The crucial + + align:start position:0% +number of independent The crucial + + + align:start position:0% +number of independent The crucial +number the number of nonzero values of + + align:start position:0% +number the number of nonzero values of + + + align:start position:0% +number the number of nonzero values of +AA transpose the number of independent + + align:start position:0% +AA transpose the number of independent + + + align:start position:0% +AA transpose the number of independent +rows in a the number of independent + + align:start position:0% +rows in a the number of independent + + + align:start position:0% +rows in a the number of independent +Columns of a it's it's measures the true + + align:start position:0% +Columns of a it's it's measures the true + + + align:start position:0% +Columns of a it's it's measures the true +the size the true size of a because the + + align:start position:0% +the size the true size of a because the + + + align:start position:0% +the size the true size of a because the +rest of a is is + + align:start position:0% +rest of a is is + + + align:start position:0% +rest of a is is +uh is sort of zero if we look at it the + + align:start position:0% +uh is sort of zero if we look at it the + + + align:start position:0% +uh is sort of zero if we look at it the +right way it's it's known from these and + + align:start position:0% +right way it's it's known from these and + + + align:start position:0% +right way it's it's known from these and +now so that's this SVD and I just want + + align:start position:0% +now so that's this SVD and I just want + + + align:start position:0% +now so that's this SVD and I just want +to point + + align:start position:0% +to point + + + align:start position:0% +to point +out what we see from there I could write + + align:start position:0% +out what we see from there I could write + + + align:start position:0% +out what we see from there I could write +that as a sum + + align:start position:0% +that as a sum + + + align:start position:0% +that as a sum +of multiplying column times number time + + align:start position:0% +of multiplying column times number time + + + align:start position:0% +of multiplying column times number time +row would be U1 Sigma 1 V1 transpose + + align:start position:0% +row would be U1 Sigma 1 V1 transpose + + + align:start position:0% +row would be U1 Sigma 1 V1 transpose +that's like the first piece and then the + + align:start position:0% +that's like the first piece and then the + + + align:start position:0% +that's like the first piece and then the +second piece would be U2 V2 so on and + + align:start position:0% +second piece would be U2 V2 so on and + + + align:start position:0% +second piece would be U2 V2 so on and +the last piece would be Ur Sigma R VR + + align:start position:0% + + + + align:start position:0% + +transpose so the beauty is this is the + + align:start position:0% +transpose so the beauty is this is the + + + align:start position:0% +transpose so the beauty is this is the +decomposition of the Matrix a we're all + + align:start position:0% +decomposition of the Matrix a we're all + + + align:start position:0% +decomposition of the Matrix a we're all +we're talking about a everything here is + + align:start position:0% +we're talking about a everything here is + + + align:start position:0% +we're talking about a everything here is +the Matrix + + align:start position:0% +the Matrix + + + align:start position:0% +the Matrix +a so what do we learn from this usually + + align:start position:0% +a so what do we learn from this usually + + + align:start position:0% +a so what do we learn from this usually +we we Sigma 1 is is greater equal Sigma + + align:start position:0% +we we Sigma 1 is is greater equal Sigma + + + align:start position:0% +we we Sigma 1 is is greater equal Sigma +2 greater equal greater equal we usually + + align:start position:0% +2 greater equal greater equal we usually + + + align:start position:0% +2 greater equal greater equal we usually +put them in descending order so this is + + align:start position:0% +put them in descending order so this is + + + align:start position:0% +put them in descending order so this is +Sigma Max here + + align:start position:0% +Sigma Max here + + + align:start position:0% +Sigma Max here +and this is Sigma + + align:start position:0% +and this is Sigma + + + align:start position:0% +and this is Sigma +Min apart from some possible zeros + + align:start position:0% +Min apart from some possible zeros + + + align:start position:0% +Min apart from some possible zeros +so this piece like tells us the most + + align:start position:0% +so this piece like tells us the most + + + align:start position:0% +so this piece like tells us the most +important part of the + + align:start position:0% +important part of the + + + align:start position:0% +important part of the +Matrix for example in images my Matrix + + align:start position:0% +Matrix for example in images my Matrix + + + align:start position:0% +Matrix for example in images my Matrix +could could I could think of it as an + + align:start position:0% +could could I could think of it as an + + + align:start position:0% +could could I could think of it as an +image right I I if you give me an image + + align:start position:0% +image right I I if you give me an image + + + align:start position:0% +image right I I if you give me an image +I could just divide it into pixels and + + align:start position:0% +I could just divide it into pixels and + + + align:start position:0% +I could just divide it into pixels and +then for each pixel I'll say put the uh + + align:start position:0% +then for each pixel I'll say put the uh + + + align:start position:0% +then for each pixel I'll say put the uh +gray level and that gives me a matrix a + + align:start position:0% +gray level and that gives me a matrix a + + + align:start position:0% +gray level and that gives me a matrix a +matrix of gray levels so let let me take + + align:start position:0% +matrix of gray levels so let let me take + + + align:start position:0% +matrix of gray levels so let let me take +a a possible application a is a + + align:start position:0% +a a possible application a is a + + + align:start position:0% +a a possible application a is a +matrix + + align:start position:0% +matrix + + + align:start position:0% +matrix +of gray levels of + + align:start position:0% +of gray levels of + + + align:start position:0% +of gray levels of +pixels + + align:start position:0% +pixels + + + align:start position:0% +pixels +okay so that's got n s or M time n + + align:start position:0% +okay so that's got n s or M time n + + + align:start position:0% +okay so that's got n s or M time n +pixels M * n entries in the matrix it's + + align:start position:0% +pixels M * n entries in the matrix it's + + + align:start position:0% +pixels M * n entries in the matrix it's +a giant Matrix and I want to compress it + + align:start position:0% +a giant Matrix and I want to compress it + + + align:start position:0% +a giant Matrix and I want to compress it +what's the good way to compress a matrix + + align:start position:0% +what's the good way to compress a matrix + + + align:start position:0% +what's the good way to compress a matrix +well this would be a very nice way if I + + align:start position:0% +well this would be a very nice way if I + + + align:start position:0% +well this would be a very nice way if I +do the + + align:start position:0% +do the + + + align:start position:0% +do the +SVD then and keep just this + + align:start position:0% +SVD then and keep just this + + + align:start position:0% +SVD then and keep just this +part say that's a very simple piece to + + align:start position:0% +part say that's a very simple piece to + + + align:start position:0% +part say that's a very simple piece to +keep it's a it's a it's a rectang m byn + + align:start position:0% +keep it's a it's a it's a rectang m byn + + + align:start position:0% +keep it's a it's a it's a rectang m byn +Matrix but it only needs M components of + + align:start position:0% +Matrix but it only needs M components of + + + align:start position:0% +Matrix but it only needs M components of +u n components of v and one number Sigma + + align:start position:0% +u n components of v and one number Sigma + + + align:start position:0% +u n components of v and one number Sigma +and it's keeping + + align:start position:0% +and it's keeping + + + align:start position:0% +and it's keeping +like the biggest piece of a we could + + align:start position:0% +like the biggest piece of a we could + + + align:start position:0% +like the biggest piece of a we could +probably recognize the image from one or + + align:start position:0% +probably recognize the image from one or + + + align:start position:0% +probably recognize the image from one or +a fraction of the total number of pieces + + align:start position:0% +a fraction of the total number of pieces + + + align:start position:0% +a fraction of the total number of pieces +right if we had an M byn Matrix its rank + + align:start position:0% +right if we had an M byn Matrix its rank + + + align:start position:0% +right if we had an M byn Matrix its rank +might be M or n if no reason why it + + align:start position:0% +might be M or n if no reason why it + + + align:start position:0% +might be M or n if no reason why it +wouldn't be full Rank and that might be + + align:start position:0% +wouldn't be full Rank and that might be + + + align:start position:0% +wouldn't be full Rank and that might be +enormous but if we kept maybe 10 the + + align:start position:0% +enormous but if we kept maybe 10 the + + + align:start position:0% +enormous but if we kept maybe 10 the +first the largest 10 uh pieces we could + + align:start position:0% +first the largest 10 uh pieces we could + + + align:start position:0% +first the largest 10 uh pieces we could +recognize the image so they + + align:start position:0% +recognize the image so they + + + align:start position:0% +recognize the image so they +the SVD is somehow taking your Matrix + + align:start position:0% +the SVD is somehow taking your Matrix + + + align:start position:0% +the SVD is somehow taking your Matrix +and separating it into the natural block + + align:start position:0% +and separating it into the natural block + + + align:start position:0% +and separating it into the natural block +building + + align:start position:0% +building + + + align:start position:0% +building +blocks the building blocks are rank + + align:start position:0% +blocks the building blocks are rank + + + align:start position:0% +blocks the building blocks are rank +one column times row and they're + + align:start position:0% +one column times row and they're + + + align:start position:0% +one column times row and they're +multiplied by these numbers that + + align:start position:0% +multiplied by these numbers that + + + align:start position:0% +multiplied by these numbers that +decrease in order and uh so this this + + align:start position:0% +decrease in order and uh so this this + + + align:start position:0% +decrease in order and uh so this this +sort of tells us something about a + + align:start position:0% +sort of tells us something about a + + + align:start position:0% +sort of tells us something about a +inverse how how how difficult it is and + + align:start position:0% +inverse how how how difficult it is and + + + align:start position:0% +inverse how how how difficult it is and +this tells us what's important about a + + align:start position:0% +this tells us what's important about a + + + align:start position:0% +this tells us what's important about a +and the difficulty + + align:start position:0% +and the difficulty + + + align:start position:0% +and the difficulty +is uh as as I was discussing before the + + align:start position:0% +is uh as as I was discussing before the + + + align:start position:0% +is uh as as I was discussing before the +class started the difficulty is if we + + align:start position:0% +class started the difficulty is if we + + + align:start position:0% +class started the difficulty is if we +have a lot of this to do and we have a + + align:start position:0% +have a lot of this to do and we have a + + + align:start position:0% +have a lot of this to do and we have a +have to do it a lot in real time then we + + align:start position:0% +have to do it a lot in real time then we + + + align:start position:0% +have to do it a lot in real time then we +have to consider how quickly can we get + + align:start position:0% +have to consider how quickly can we get + + + align:start position:0% +have to consider how quickly can we get +the + + align:start position:0% + + + + align:start position:0% + +SVD I'm beginning to think like Lincoln + + align:start position:0% +SVD I'm beginning to think like Lincoln + + + align:start position:0% +SVD I'm beginning to think like Lincoln +Labs needs a department of numerical + + align:start position:0% +Labs needs a department of numerical + + + align:start position:0% +Labs needs a department of numerical +linear algebra because uh the problems + + align:start position:0% +linear algebra because uh the problems + + + align:start position:0% +linear algebra because uh the problems +you're facing are this these questions + + align:start position:0% +you're facing are this these questions + + + align:start position:0% +you're facing are this these questions +of of efficient uh calculation of very + + align:start position:0% +of of efficient uh calculation of very + + + align:start position:0% +of of efficient uh calculation of very +very large systems and uh do you do it + + align:start position:0% +very large systems and uh do you do it + + + align:start position:0% +very large systems and uh do you do it +on uh do you use QR what do you do do + + align:start position:0% +on uh do you use QR what do you do do + + + align:start position:0% +on uh do you use QR what do you do do +you use uh uh elimination do you do you + + align:start position:0% +you use uh uh elimination do you do you + + + align:start position:0% +you use uh uh elimination do you do you +do it in parallel do you do it on what + + align:start position:0% +do it in parallel do you do it on what + + + align:start position:0% +do it in parallel do you do it on what +processors how how to make that + + align:start position:0% +processors how how to make that + + + align:start position:0% +processors how how to make that +efficient I mean it's really uh Central + + align:start position:0% +efficient I mean it's really uh Central + + + align:start position:0% +efficient I mean it's really uh Central +issue and it's certainly part of these + + align:start position:0% +issue and it's certainly part of these + + + align:start position:0% +issue and it's certainly part of these +lectures uh it's not the only + + align:start position:0% +lectures uh it's not the only + + + align:start position:0% +lectures uh it's not the only +part uh but I'm happy to let me say this + + align:start position:0% +part uh but I'm happy to let me say this + + + align:start position:0% +part uh but I'm happy to let me say this +again I'm I'm really happy to know what + + align:start position:0% +again I'm I'm really happy to know what + + + align:start position:0% +again I'm I'm really happy to know what +the problems that are arising are and + + align:start position:0% +the problems that are arising are and + + + align:start position:0% +the problems that are arising are and +especially if I'm able to translate them + + align:start position:0% +especially if I'm able to translate them + + + align:start position:0% +especially if I'm able to translate them +into a familiar language and and sort of + + align:start position:0% +into a familiar language and and sort of + + + align:start position:0% +into a familiar language and and sort of +Rec identify well what is the what is + + align:start position:0% +Rec identify well what is the what is + + + align:start position:0% +Rec identify well what is the what is +the underlying problem here uh is it + + align:start position:0% +the underlying problem here uh is it + + + align:start position:0% +the underlying problem here uh is it +uh and uh with + + align:start position:0% +uh and uh with + + + align:start position:0% +uh and uh with +SVD we have to say clearly that it's + + align:start position:0% +SVD we have to say clearly that it's + + + align:start position:0% +SVD we have to say clearly that it's +even though people have found very good + + align:start position:0% +even though people have found very good + + + align:start position:0% +even though people have found very good +algorithms for it it's still a heck of a + + align:start position:0% +algorithms for it it's still a heck of a + + + align:start position:0% +algorithms for it it's still a heck of a +lot of work uh basically you have an IG + + align:start position:0% +lot of work uh basically you have an IG + + + align:start position:0% +lot of work uh basically you have an IG +value problem to + + align:start position:0% +value problem to + + + align:start position:0% +value problem to +do and igen value problems take you know + + align:start position:0% +do and igen value problems take you know + + + align:start position:0% +do and igen value problems take you know +that bit more time than uh QR or uh uh + + align:start position:0% +that bit more time than uh QR or uh uh + + + align:start position:0% +that bit more time than uh QR or uh uh +LDL transpose + + align:start position:0% +LDL transpose + + + align:start position:0% +LDL transpose +elimination okay uh any comment you feel + + align:start position:0% +elimination okay uh any comment you feel + + + align:start position:0% +elimination okay uh any comment you feel +free to make a comment because this is + + align:start position:0% +free to make a comment because this is + + + align:start position:0% +free to make a comment because this is +like preliminary before I launch into uh + + align:start position:0% +like preliminary before I launch into uh + + + align:start position:0% +like preliminary before I launch into uh +today's + + align:start position:0% +today's + + + align:start position:0% +today's +lecture any or or comments offline um + + align:start position:0% +lecture any or or comments offline um + + + align:start position:0% +lecture any or or comments offline um +are are totally welcome okay ready to go + + align:start position:0% +are are totally welcome okay ready to go + + + align:start position:0% +are are totally welcome okay ready to go +on Lee squares okay so so this part I + + align:start position:0% +on Lee squares okay so so this part I + + + align:start position:0% +on Lee squares okay so so this part I +take as known the the the uh the + + align:start position:0% +take as known the the the uh the + + + align:start position:0% +take as known the the the uh the +um the re we got to that either by a + + align:start position:0% +um the re we got to that either by a + + + align:start position:0% +um the re we got to that either by a +minim + + align:start position:0% +minim + + + align:start position:0% +minim +minimization of the error B minus Au U + + align:start position:0% +minimization of the error B minus Au U + + + align:start position:0% +minimization of the error B minus Au U +squared or geometrically we got to that + + align:start position:0% +squared or geometrically we got to that + + + align:start position:0% +squared or geometrically we got to that +by a + + align:start position:0% +by a + + + align:start position:0% +by a +projection of + + align:start position:0% +projection of + + + align:start position:0% +projection of +B + + align:start position:0% +B + + + align:start position:0% +B +onto the column space of + + align:start position:0% +onto the column space of + + + align:start position:0% +onto the column space of +a but we got there it's in on the + + align:start position:0% +a but we got there it's in on the + + + align:start position:0% +a but we got there it's in on the +videotape so I don't uh it's on the on + + align:start position:0% +videotape so I don't uh it's on the on + + + align:start position:0% +videotape so I don't uh it's on the on +the record now I'm ready to discuss + + align:start position:0% +the record now I'm ready to discuss + + + align:start position:0% +the record now I'm ready to discuss +point + + align:start position:0% +point + + + align:start position:0% +point +two why the weights okay + + align:start position:0% +two why the weights okay + + + align:start position:0% +two why the weights okay +now + + align:start position:0% +now + + + align:start position:0% +now +okay uh I have to I would like to know + + align:start position:0% +okay uh I have to I would like to know + + + align:start position:0% +okay uh I have to I would like to know +why these are the appropriate weights + + align:start position:0% +why these are the appropriate weights + + + align:start position:0% +why these are the appropriate weights +the the sigma and so let's remember what + + align:start position:0% +the the sigma and so let's remember what + + + align:start position:0% +the the sigma and so let's remember what +Sigma is the The covariance Matrix + + align:start position:0% + + + + align:start position:0% + +Sigma and if I'm trying to remember what + + align:start position:0% +Sigma and if I'm trying to remember what + + + align:start position:0% +Sigma and if I'm trying to remember what +is the covariance of I might put a v to + + align:start position:0% +is the covariance of I might put a v to + + + align:start position:0% +is the covariance of I might put a v to +remind myself it's + + align:start position:0% +remind myself it's + + + align:start position:0% +remind myself it's +the our system is coming to us with + + align:start position:0% +the our system is coming to us with + + + align:start position:0% +the our system is coming to us with +noise so we get Au equal B say + + align:start position:0% +noise so we get Au equal B say + + + align:start position:0% +noise so we get Au equal B say +minus noise + + align:start position:0% + + + + align:start position:0% + +e and of course we don't know exactly + + align:start position:0% +e and of course we don't know exactly + + + align:start position:0% +e and of course we don't know exactly +what that noise + + align:start position:0% +what that noise + + + align:start position:0% +what that noise +is but we may + + align:start position:0% +is but we may + + + align:start position:0% +is but we may +know uh sort of what its variance is + + align:start position:0% +know uh sort of what its variance is + + + align:start position:0% +know uh sort of what its variance is +what what what's it what its expectation + + align:start position:0% +what what what's it what its expectation + + + align:start position:0% +what what what's it what its expectation +is is the average noise + + align:start position:0% +is is the average noise + + + align:start position:0% +is is the average noise +zero let's say it is because if the + + align:start position:0% +zero let's say it is because if the + + + align:start position:0% +zero let's say it is because if the +average noise isn't zero we'll subtract + + align:start position:0% +average noise isn't zero we'll subtract + + + align:start position:0% +average noise isn't zero we'll subtract +off that average to to get noise that + + align:start position:0% +off that average to to get noise that + + + align:start position:0% +off that average to to get noise that +has average zero so I'm ass I'm going to + + align:start position:0% +has average zero so I'm ass I'm going to + + + align:start position:0% +has average zero so I'm ass I'm going to +always assume that the expected value of + + align:start position:0% +always assume that the expected value of + + + align:start position:0% +always assume that the expected value of +e of the of this error B minus AU + + align:start position:0% +e of the of this error B minus AU + + + align:start position:0% +e of the of this error B minus AU +is + + align:start position:0% +is + + + align:start position:0% +is +zero let's but + + align:start position:0% +zero let's but + + + align:start position:0% +zero let's but +now but it that doesn't mean we expect + + align:start position:0% +now but it that doesn't mean we expect + + + align:start position:0% +now but it that doesn't mean we expect +it to be zero we expect its average to + + align:start position:0% +it to be zero we expect its average to + + + align:start position:0% +it to be zero we expect its average to +be zero it's more as as as likely to be + + align:start position:0% +be zero it's more as as as likely to be + + + align:start position:0% +be zero it's more as as as likely to be +plus as + + align:start position:0% +plus as + + + align:start position:0% +plus as +minus roughly speaking but but if we + + align:start position:0% +minus roughly speaking but but if we + + + align:start position:0% +minus roughly speaking but but if we +Square it then we get the so the this is + + align:start position:0% +Square it then we get the so the this is + + + align:start position:0% +Square it then we get the so the this is +the + + align:start position:0% + + + + align:start position:0% + +expectation the average value of + + align:start position:0% +expectation the average value of + + + align:start position:0% +expectation the average value of +the error squared it's so essentially + + align:start position:0% +the error squared it's so essentially + + + align:start position:0% +the error squared it's so essentially +what I'm going to put in here is e^ squ + + align:start position:0% +what I'm going to put in here is e^ squ + + + align:start position:0% +what I'm going to put in here is e^ squ +right the expectation of e is zero and + + align:start position:0% +right the expectation of e is zero and + + + align:start position:0% +right the expectation of e is zero and +now I'm looking at the expectation of e + + align:start position:0% +now I'm looking at the expectation of e + + + align:start position:0% +now I'm looking at the expectation of e +squ but e is a + + align:start position:0% +squ but e is a + + + align:start position:0% +squ but e is a +vector we've got here + + align:start position:0% + + + + align:start position:0% + +M uh + + align:start position:0% +M uh + + + align:start position:0% +M uh +measurements MBS M + + align:start position:0% +measurements MBS M + + + align:start position:0% +measurements MBS M +errors so this is a and those + + align:start position:0% +errors so this is a and those + + + align:start position:0% +errors so this is a and those +errors those M errors from the from the + + align:start position:0% +errors those M errors from the from the + + + align:start position:0% +errors those M errors from the from the +M measurements may + + align:start position:0% +M measurements may + + + align:start position:0% +M measurements may +be independent and identical just all + + align:start position:0% +be independent and identical just all + + + align:start position:0% +be independent and identical just all +all + + align:start position:0% +all + + + align:start position:0% +all +uh and very frequently very frequently + + align:start position:0% +uh and very frequently very frequently + + + align:start position:0% +uh and very frequently very frequently +uh so they we might use the word white + + align:start position:0% +uh so they we might use the word white + + + align:start position:0% +uh so they we might use the word white +noise or something for the error in that + + align:start position:0% +noise or something for the error in that + + + align:start position:0% +noise or something for the error in that +case uh or they might be correlated so + + align:start position:0% +case uh or they might be correlated so + + + align:start position:0% +case uh or they might be correlated so +this Matrix tells us and you've seen it + + align:start position:0% +this Matrix tells us and you've seen it + + + align:start position:0% +this Matrix tells us and you've seen it +before + + align:start position:0% + + + + align:start position:0% + +that's what that's the covariance Matrix + + align:start position:0% +that's what that's the covariance Matrix + + + align:start position:0% +that's what that's the covariance Matrix +so let's just look at a typical entry + + align:start position:0% +so let's just look at a typical entry + + + align:start position:0% +so let's just look at a typical entry +the + + align:start position:0% +the + + + align:start position:0% +the +JJ entry + + align:start position:0% +JJ entry + + + align:start position:0% +JJ entry +is the expected value of the e error + + align:start position:0% +is the expected value of the e error + + + align:start position:0% +is the expected value of the e error +times the J + + align:start position:0% + + + + align:start position:0% + +error + + align:start position:0% +error + + + align:start position:0% +error +and Independence means that the Matrix + + align:start position:0% +and Independence means that the Matrix + + + align:start position:0% +and Independence means that the Matrix +is what so what's the Matrix so independ + + align:start position:0% +is what so what's the Matrix so independ + + + align:start position:0% +is what so what's the Matrix so independ +observations would mean uh in + + align:start position:0% +observations would mean uh in + + + align:start position:0% +observations would mean uh in +independent + + align:start position:0% +independent + + + align:start position:0% +independent +errors would mean + + align:start position:0% +errors would mean + + + align:start position:0% +errors would mean +what that that that the Matrix is + + align:start position:0% +what that that that the Matrix is + + + align:start position:0% +what that that that the Matrix is +diagonal right that that when I is + + align:start position:0% +diagonal right that that when I is + + + align:start position:0% +diagonal right that that when I is +different from + + align:start position:0% +different from + + + align:start position:0% +different from +J there's no there's no connection + + align:start position:0% +J there's no there's no connection + + + align:start position:0% +J there's no there's no connection +between those two errors The Joint + + align:start position:0% +between those two errors The Joint + + + align:start position:0% +between those two errors The Joint +probability is just one probability + + align:start position:0% +probability is just one probability + + + align:start position:0% +probability is just one probability +times the other in which case we can + + align:start position:0% +times the other in which case we can + + + align:start position:0% +times the other in which case we can +like separate this into two integrals + + align:start position:0% +like separate this into two integrals + + + align:start position:0% +like separate this into two integrals +and + + align:start position:0% +and + + + align:start position:0% +and +this is our assumption that the + + align:start position:0% +this is our assumption that the + + + align:start position:0% +this is our assumption that the +expectation of a single one is zero so + + align:start position:0% +expectation of a single one is zero so + + + align:start position:0% +expectation of a single one is zero so +we get 0 time 0 we get zero so + + align:start position:0% +we get 0 time 0 we get zero so + + + align:start position:0% +we get 0 time 0 we get zero so +independent independent errors would be + + align:start position:0% +independent independent errors would be + + + align:start position:0% +independent independent errors would be +uh uh Sigma i j would be zero + + align:start position:0% +uh uh Sigma i j would be zero + + + align:start position:0% +uh uh Sigma i j would be zero +okay uh yeah is that or this would be + + align:start position:0% +okay uh yeah is that or this would be + + + align:start position:0% +okay uh yeah is that or this would be +zero anyway yeah yeah the the the JJ + + align:start position:0% +zero anyway yeah yeah the the the JJ + + + align:start position:0% +zero anyway yeah yeah the the the JJ +entry independent errors it you said it + + align:start position:0% +entry independent errors it you said it + + + align:start position:0% +entry independent errors it you said it +better + + align:start position:0% +better + + + align:start position:0% +better +diagonal Sigma and identical errors what + + align:start position:0% +diagonal Sigma and identical errors what + + + align:start position:0% +diagonal Sigma and identical errors what +what would that + + align:start position:0% + + + + align:start position:0% + +mean because you often see these words + + align:start position:0% +mean because you often see these words + + + align:start position:0% +mean because you often see these words +in fact they get abbreviated to I I + + align:start position:0% +in fact they get abbreviated to I I + + + align:start position:0% +in fact they get abbreviated to I I +because they this is an assumption this + + align:start position:0% +because they this is an assumption this + + + align:start position:0% +because they this is an assumption this +this whiteness assumption is made so + + align:start position:0% +this whiteness assumption is made so + + + align:start position:0% +this whiteness assumption is made so +often and when they're identical what + + align:start position:0% +often and when they're identical what + + + align:start position:0% +often and when they're identical what +what would that + + align:start position:0% +what would that + + + align:start position:0% +what would that +mean right and and and for their Matrix + + align:start position:0% +mean right and and and for their Matrix + + + align:start position:0% +mean right and and and for their Matrix +that will mean that + + align:start position:0% +that will mean that + + + align:start position:0% +that will mean that +Sigma yeah it's just a multiple of I + + align:start position:0% +Sigma yeah it's just a multiple of I + + + align:start position:0% +Sigma yeah it's just a multiple of I +Sigma equals some whatever this this + + align:start position:0% +Sigma equals some whatever this this + + + align:start position:0% +Sigma equals some whatever this this +common Sigma times I right so that very + + align:start position:0% +common Sigma times I right so that very + + + align:start position:0% +common Sigma times I right so that very +often we we uh assume that and just to + + align:start position:0% +often we we uh assume that and just to + + + align:start position:0% +often we we uh assume that and just to +mention we can always you can always + + align:start position:0% +mention we can always you can always + + + align:start position:0% +mention we can always you can always +look at what we're we we could always + + align:start position:0% +look at what we're we we could always + + + align:start position:0% +look at what we're we we could always +change variables whiten the the the + + align:start position:0% +change variables whiten the the the + + + align:start position:0% +change variables whiten the the the +Errors By by a change of variables we if + + align:start position:0% +Errors By by a change of variables we if + + + align:start position:0% +Errors By by a change of variables we if +we if we uh put part of this Sigma into + + align:start position:0% +we if we uh put part of this Sigma into + + + align:start position:0% +we if we uh put part of this Sigma into +our problem the effect is to whiten the + + align:start position:0% +our problem the effect is to whiten the + + + align:start position:0% +our problem the effect is to whiten the +ears in fact if I put square root of + + align:start position:0% +ears in fact if I put square root of + + + align:start position:0% +ears in fact if I put square root of +Sigma in here that will uh uh have have + + align:start position:0% +Sigma in here that will uh uh have have + + + align:start position:0% +Sigma in here that will uh uh have have +that effect so uh I can get to that if I + + align:start position:0% +that effect so uh I can get to that if I + + + align:start position:0% +that effect so uh I can get to that if I +want to but but uh uh now I better say + + align:start position:0% +want to but but uh uh now I better say + + + align:start position:0% +want to but but uh uh now I better say +something quite important that + + align:start position:0% +something quite important that + + + align:start position:0% +something quite important that +uh that looking ahead we aren't going to + + align:start position:0% +uh that looking ahead we aren't going to + + + align:start position:0% +uh that looking ahead we aren't going to +assume that all our errors are + + align:start position:0% +assume that all our errors are + + + align:start position:0% +assume that all our errors are +independent or identical so I'm not + + align:start position:0% +independent or identical so I'm not + + + align:start position:0% +independent or identical so I'm not +going to assume that Sigma is so simple + + align:start position:0% +going to assume that Sigma is so simple + + + align:start position:0% +going to assume that Sigma is so simple +but when it gets + + align:start position:0% +but when it gets + + + align:start position:0% +but when it gets +to recursive stuff so that sort of + + align:start position:0% +to recursive stuff so that sort of + + + align:start position:0% +to recursive stuff so that sort of +things are + + align:start position:0% +things are + + + align:start position:0% +things are +happening you know we have some + + align:start position:0% +happening you know we have some + + + align:start position:0% +happening you know we have some +information and then we get some new + + align:start position:0% +information and then we get some new + + + align:start position:0% +information and then we get some new +information then I will be + + align:start position:0% +information then I will be + + + align:start position:0% +information then I will be +assuming that the + + align:start position:0% +assuming that the + + + align:start position:0% +assuming that the +sigma for the old + + align:start position:0% +sigma for the old + + + align:start position:0% +sigma for the old +information and for the new are are + + align:start position:0% +information and for the new are are + + + align:start position:0% +information and for the new are are +independent uh I'll assume that the old + + align:start position:0% +independent uh I'll assume that the old + + + align:start position:0% +independent uh I'll assume that the old +errors and the new errors are + + align:start position:0% +errors and the new errors are + + + align:start position:0% +errors and the new errors are +independent so that my so so + + align:start position:0% +independent so that my so so + + + align:start position:0% +independent so that my so so +typically + + align:start position:0% +typically + + + align:start position:0% +typically +so just while I'm discussing + + align:start position:0% +so just while I'm discussing + + + align:start position:0% +so just while I'm discussing +Sigma what if imagine a I hope you're + + align:start position:0% +Sigma what if imagine a I hope you're + + + align:start position:0% +Sigma what if imagine a I hope you're +imagining a situation in which maybe I + + align:start position:0% +imagining a situation in which maybe I + + + align:start position:0% +imagining a situation in which maybe I +better start start writing this uh + + align:start position:0% +better start start writing this uh + + + align:start position:0% +better start start writing this uh +recursive now I'm I'm combining these + + align:start position:0% +recursive now I'm I'm combining these + + + align:start position:0% +recursive now I'm I'm combining these +discussions here so in the recursive + + align:start position:0% +discussions here so in the recursive + + + align:start position:0% +discussions here so in the recursive +stuff what's my problem I have + + align:start position:0% +stuff what's my problem I have + + + align:start position:0% +stuff what's my problem I have +a there's a there's old there's new + + align:start position:0% +a there's a there's old there's new + + + align:start position:0% +a there's a there's old there's new +there's old data and there's new + + align:start position:0% +there's old data and there's new + + + align:start position:0% +there's old data and there's new +data and my U it's the same U same + + align:start position:0% + + + + align:start position:0% + +U so I could maybe I have one set of + + align:start position:0% +U so I could maybe I have one set of + + + align:start position:0% +U so I could maybe I have one set of +measurements where the coefficient + + align:start position:0% +measurements where the coefficient + + + align:start position:0% +measurements where the coefficient +Matrix is some a new a old sorry the old + + align:start position:0% + + + + align:start position:0% + +guy and then a second set of + + align:start position:0% +guy and then a second set of + + + align:start position:0% +guy and then a second set of +measurements where the of the same U so + + align:start position:0% +measurements where the of the same U so + + + align:start position:0% +measurements where the of the same U so +so it's the same U but new errors new + + align:start position:0% +so it's the same U but new errors new + + + align:start position:0% +so it's the same U but new errors new +measurements and and therefore new + + align:start position:0% +measurements and and therefore new + + + align:start position:0% +measurements and and therefore new +errors and what I want to do is I want + + align:start position:0% +errors and what I want to do is I want + + + align:start position:0% +errors and what I want to do is I want +to solve that + + align:start position:0% +to solve that + + + align:start position:0% +to solve that +problem following all the + + align:start position:0% +problem following all the + + + align:start position:0% +problem following all the +rules but getting the answer in this + + align:start position:0% +rules but getting the answer in this + + + align:start position:0% +rules but getting the answer in this +form + + align:start position:0% +form + + + align:start position:0% +form +so the idea is this problem should get + + align:start position:0% +so the idea is this problem should get + + + align:start position:0% +so the idea is this problem should get +me an if I do it right could get me an + + align:start position:0% +me an if I do it right could get me an + + + align:start position:0% +me an if I do it right could get me an +answer in this + + align:start position:0% +answer in this + + + align:start position:0% +answer in this +form but I will have to + + align:start position:0% +form but I will have to + + + align:start position:0% +form but I will have to +assume to make this come out well I'll + + align:start position:0% +assume to make this come out well I'll + + + align:start position:0% +assume to make this come out well I'll +have to assume that the old errors and + + align:start position:0% +have to assume that the old errors and + + + align:start position:0% +have to assume that the old errors and +new errors are not + + align:start position:0% +new errors are not + + + align:start position:0% +new errors are not +correlated okay so the sigma for this + + align:start position:0% +correlated okay so the sigma for this + + + align:start position:0% +correlated okay so the sigma for this +for this like combined problem the sigma + + align:start position:0% +for this like combined problem the sigma + + + align:start position:0% +for this like combined problem the sigma +combined will be will + + align:start position:0% +combined will be will + + + align:start position:0% +combined will be will +be uh a + + align:start position:0% +be uh a + + + align:start position:0% +be uh a +sigma for the + + align:start position:0% +sigma for the + + + align:start position:0% +sigma for the +old errors no correlation to the sigma + + align:start position:0% +old errors no correlation to the sigma + + + align:start position:0% +old errors no correlation to the sigma +for the new + + align:start position:0% +for the new + + + align:start position:0% +for the new +errors do you see what I'm saying I I I + + align:start position:0% +errors do you see what I'm saying I I I + + + align:start position:0% +errors do you see what I'm saying I I I +I won't be required to assume these are + + align:start position:0% + + + + align:start position:0% + +diagonal nor will I required to be to + + align:start position:0% +diagonal nor will I required to be to + + + align:start position:0% +diagonal nor will I required to be to +assume that they're the same in any way + + align:start position:0% +assume that they're the same in any way + + + align:start position:0% +assume that they're the same in any way +in fact we might have four old + + align:start position:0% +in fact we might have four old + + + align:start position:0% +in fact we might have four old +measurements and one new one or 4,000 + + align:start position:0% +measurements and one new one or 4,000 + + + align:start position:0% +measurements and one new one or 4,000 +old measurements and 10 new + + align:start position:0% +old measurements and 10 new + + + align:start position:0% +old measurements and 10 new +ones it wouldn't even be the same size + + align:start position:0% +ones it wouldn't even be the same size + + + align:start position:0% +ones it wouldn't even be the same size +but the you see that what those zeros + + align:start position:0% +but the you see that what those zeros + + + align:start position:0% +but the you see that what those zeros +are saying is that old and new errors + + align:start position:0% +are saying is that old and new errors + + + align:start position:0% +are saying is that old and new errors +are not correlated okay good so that's + + align:start position:0% +are not correlated okay good so that's + + + align:start position:0% +are not correlated okay good so that's +some discussion of Sigma but now let me + + align:start position:0% +some discussion of Sigma but now let me + + + align:start position:0% +some discussion of Sigma but now let me +come back to this weighted + + align:start position:0% +come back to this weighted + + + align:start position:0% +come back to this weighted +stuff + + align:start position:0% +stuff + + + align:start position:0% +stuff +why do we so so I'm now coming back to + + align:start position:0% +why do we so so I'm now coming back to + + + align:start position:0% +why do we so so I'm now coming back to +weighted not ready for a recursive yet + + align:start position:0% +weighted not ready for a recursive yet + + + align:start position:0% +weighted not ready for a recursive yet +I'm I'm trying to identify what's our + + align:start position:0% +I'm I'm trying to identify what's our + + + align:start position:0% +I'm I'm trying to identify what's our +equation then I think about how to solve + + align:start position:0% +equation then I think about how to solve + + + align:start position:0% +equation then I think about how to solve +it recursively but let's why is this our + + align:start position:0% +it recursively but let's why is this our + + + align:start position:0% +it recursively but let's why is this our +this is our Central equation of the + + align:start position:0% +this is our Central equation of the + + + align:start position:0% +this is our Central equation of the +whole of the whole lecture + + align:start position:0% +whole of the whole lecture + + + align:start position:0% +whole of the whole lecture +absolutely so I've made a specific + + align:start position:0% +absolutely so I've made a specific + + + align:start position:0% +absolutely so I've made a specific +choice of of these waiting Matrix M of + + align:start position:0% +choice of of these waiting Matrix M of + + + align:start position:0% +choice of of these waiting Matrix M of +that waiting Matrix and and + + align:start position:0% +that waiting Matrix and and + + + align:start position:0% +that waiting Matrix and and +uh and it's a it will seem a reasonable + + align:start position:0% +uh and it's a it will seem a reasonable + + + align:start position:0% +uh and it's a it will seem a reasonable +choice to you that we Sigma a small + + align:start position:0% +choice to you that we Sigma a small + + + align:start position:0% +choice to you that we Sigma a small +Sigma a small variance so I'm repeating + + align:start position:0% +Sigma a small variance so I'm repeating + + + align:start position:0% +Sigma a small variance so I'm repeating +what I've said back in the Le squares + + align:start position:0% +what I've said back in the Le squares + + + align:start position:0% +what I've said back in the Le squares +lecture a small variance + + align:start position:0% +lecture a small variance + + + align:start position:0% +lecture a small variance +means small errors reliable measurements + + align:start position:0% +means small errors reliable measurements + + + align:start position:0% +means small errors reliable measurements +so we weight those those more heavily so + + align:start position:0% +so we weight those those more heavily so + + + align:start position:0% +so we weight those those more heavily so +small variance and then taking inverses + + align:start position:0% +small variance and then taking inverses + + + align:start position:0% +small variance and then taking inverses +means heavier weight fine but why is + + align:start position:0% +means heavier weight fine but why is + + + align:start position:0% +means heavier weight fine but why is +this exactly the right way so that's one + + align:start position:0% +this exactly the right way so that's one + + + align:start position:0% +this exactly the right way so that's one +point why why is I mean it's sort of the + + align:start position:0% +point why why is I mean it's sort of the + + + align:start position:0% +point why why is I mean it's sort of the +the pattern is reasonable to weit the + + align:start position:0% +the pattern is reasonable to weit the + + + align:start position:0% +the pattern is reasonable to weit the +more reliable measurements with smaller + + align:start position:0% +more reliable measurements with smaller + + + align:start position:0% +more reliable measurements with smaller +errors High heavier weights but that + + align:start position:0% +errors High heavier weights but that + + + align:start position:0% +errors High heavier weights but that +does it just right and what is just + + align:start position:0% +does it just right and what is just + + + align:start position:0% +does it just right and what is just +right about that and then the other key + + align:start position:0% +right about that and then the other key + + + align:start position:0% +right about that and then the other key +point is that in a lot of problems it's + + align:start position:0% +point is that in a lot of problems it's + + + align:start position:0% +point is that in a lot of problems it's +not just you hat the best parameters + + align:start position:0% +not just you hat the best parameters + + + align:start position:0% +not just you hat the best parameters +that we're + + align:start position:0% +that we're + + + align:start position:0% +that we're +after we're after also some information + + align:start position:0% +after we're after also some information + + + align:start position:0% +after we're after also some information +of how reliable they are how reliable is + + align:start position:0% +of how reliable they are how reliable is + + + align:start position:0% +of how reliable they are how reliable is +you hat we so we so + + align:start position:0% + + + + align:start position:0% + +input is measurements B and their + + align:start position:0% +input is measurements B and their + + + align:start position:0% +input is measurements B and their +variances Sigma B what's the + + align:start position:0% + + + + align:start position:0% + +output the output will be U + + align:start position:0% +output the output will be U + + + align:start position:0% +output the output will be U +hat the + + align:start position:0% +hat the + + + align:start position:0% +hat the +best estimate of the parameters and the + + align:start position:0% +best estimate of the parameters and the + + + align:start position:0% +best estimate of the parameters and the +the + + align:start position:0% +the + + + align:start position:0% +the +variance it's variance how reliable is + + align:start position:0% +variance it's variance how reliable is + + + align:start position:0% +variance it's variance how reliable is +that and and there's going to be of + + align:start position:0% +that and and there's going to be of + + + align:start position:0% +that and and there's going to be of +course a connection between + + align:start position:0% +course a connection between + + + align:start position:0% +course a connection between +these and + + align:start position:0% +these and + + + align:start position:0% +these and +uh + + align:start position:0% +uh + + + align:start position:0% +uh +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +um + + align:start position:0% +um + + + align:start position:0% +um +uh but but the formula for this W uh is + + align:start position:0% +uh but but the formula for this W uh is + + + align:start position:0% +uh but but the formula for this W uh is +it maybe more this may this may be more + + align:start position:0% +it maybe more this may this may be more + + + align:start position:0% +it maybe more this may this may be more +important than that is what I'm trying + + align:start position:0% +important than that is what I'm trying + + + align:start position:0% +important than that is what I'm trying +to say this is this thing comes from a + + align:start position:0% +to say this is this thing comes from a + + + align:start position:0% +to say this is this thing comes from a +specific experiment that gave us a + + align:start position:0% +specific experiment that gave us a + + + align:start position:0% +specific experiment that gave us a +specific you know we we made one we made + + align:start position:0% +specific you know we we made one we made + + + align:start position:0% +specific you know we we made one we made +one run one sample we got we got some + + align:start position:0% +one run one sample we got we got some + + + align:start position:0% +one run one sample we got we got some +B's we some measurements we computed you + + align:start position:0% +B's we some measurements we computed you + + + align:start position:0% +B's we some measurements we computed you +hat if we had if we ran it again we + + align:start position:0% +hat if we had if we ran it again we + + + align:start position:0% +hat if we had if we ran it again we +would get a different you hat so then + + align:start position:0% +would get a different you hat so then + + + align:start position:0% +would get a different you hat so then +you naturally ask well wait a minute I + + align:start position:0% +you naturally ask well wait a minute I + + + align:start position:0% +you naturally ask well wait a minute I +can't just run it and run it run it + + align:start position:0% +can't just run it and run it run it + + + align:start position:0% +can't just run it and run it run it +forever what are the statistics of you + + align:start position:0% +forever what are the statistics of you + + + align:start position:0% +forever what are the statistics of you +hat they they tell us like how good is + + align:start position:0% +hat they they tell us like how good is + + + align:start position:0% +hat they they tell us like how good is +the experiment before we run it + + align:start position:0% +the experiment before we run it + + + align:start position:0% +the experiment before we run it +and uh that's the information here so + + align:start position:0% +and uh that's the information here so + + + align:start position:0% +and uh that's the information here so +this information is is is Central okay + + align:start position:0% +this information is is is Central okay + + + align:start position:0% +this information is is is Central okay +so now the beauty + + align:start position:0% + + + + align:start position:0% + +is the beauty and in many cases it's + + align:start position:0% +is the beauty and in many cases it's + + + align:start position:0% +is the beauty and in many cases it's +many formulas involve the inverse of + + align:start position:0% +many formulas involve the inverse of + + + align:start position:0% +many formulas involve the inverse of +that so can I introduce a symbol for the + + align:start position:0% +that so can I introduce a symbol for the + + + align:start position:0% +that so can I introduce a symbol for the +inverse of that of that + + align:start position:0% +inverse of that of that + + + align:start position:0% +inverse of that of that +Matrix I I'll let p be the + + align:start position:0% +Matrix I I'll let p be the + + + align:start position:0% +Matrix I I'll let p be the +inverse of this Sigma you have it's the + + align:start position:0% +inverse of this Sigma you have it's the + + + align:start position:0% +inverse of this Sigma you have it's the +inverse is that is that okay I just I'm + + align:start position:0% +inverse is that is that okay I just I'm + + + align:start position:0% +inverse is that is that okay I just I'm +introducing a a a letter for the inverse + + align:start position:0% +introducing a a a letter for the inverse + + + align:start position:0% +introducing a a a letter for the inverse +Matrix okay so that if I know to know p + + align:start position:0% +Matrix okay so that if I know to know p + + + align:start position:0% +Matrix okay so that if I know to know p +is to know Sigma and to know Sigma is to + + align:start position:0% +is to know Sigma and to know Sigma is to + + + align:start position:0% +is to know Sigma and to know Sigma is to +know P one's the inverse of the other + + align:start position:0% +know P one's the inverse of the other + + + align:start position:0% +know P one's the inverse of the other +okay and it just happens that a lot of + + align:start position:0% +okay and it just happens that a lot of + + + align:start position:0% +okay and it just happens that a lot of +formulas come out especially nice for + + align:start position:0% +formulas come out especially nice for + + + align:start position:0% +formulas come out especially nice for +the inverse p and + + align:start position:0% +the inverse p and + + + align:start position:0% +the inverse p and +and okay right all right let me see if I + + align:start position:0% +and okay right all right let me see if I + + + align:start position:0% +and okay right all right let me see if I +can get + + align:start position:0% +can get + + + align:start position:0% +can get +um I want to get the get the main + + align:start position:0% +um I want to get the get the main + + + align:start position:0% +um I want to get the get the main +formula here that connects this to this + + align:start position:0% +formula here that connects this to this + + + align:start position:0% +formula here that connects this to this +okay let's see if I can all right let's + + align:start position:0% +okay let's see if I can all right let's + + + align:start position:0% +okay let's see if I can all right let's +see if I can + + align:start position:0% +see if I can + + + align:start position:0% +see if I can +see if I look at this + + align:start position:0% +see if I look at this + + + align:start position:0% +see if I look at this +equation it gives me U had in terms of B + + align:start position:0% +equation it gives me U had in terms of B + + + align:start position:0% +equation it gives me U had in terms of B +in a linear way right U hat is some L + + align:start position:0% +in a linear way right U hat is some L + + + align:start position:0% +in a linear way right U hat is some L +some + + align:start position:0% +some + + + align:start position:0% +some +Matrix so I I can if I talk about + + align:start position:0% +Matrix so I I can if I talk about + + + align:start position:0% +Matrix so I I can if I talk about +formulas for a moment U hat is if I just + + align:start position:0% +formulas for a moment U hat is if I just + + + align:start position:0% +formulas for a moment U hat is if I just +read all that stuff off it's this a + + align:start position:0% +read all that stuff off it's this a + + + align:start position:0% +read all that stuff off it's this a +transpose Sigma so Sigma B inverse a + + align:start position:0% +transpose Sigma so Sigma B inverse a + + + align:start position:0% +transpose Sigma so Sigma B inverse a +inverse put that all over there times a + + align:start position:0% +inverse put that all over there times a + + + align:start position:0% +inverse put that all over there times a +transpose Sigma + + align:start position:0% +transpose Sigma + + + align:start position:0% +transpose Sigma +B + + align:start position:0% + + + + align:start position:0% + +inverse time B + + align:start position:0% +inverse time B + + + align:start position:0% +inverse time B +and for convenience I might recognize + + align:start position:0% +and for convenience I might recognize + + + align:start position:0% +and for convenience I might recognize +that that + + align:start position:0% +that that + + + align:start position:0% +that that +some made some + + align:start position:0% +some made some + + + align:start position:0% +some made some +linear some Matrix applied to + + align:start position:0% +linear some Matrix applied to + + + align:start position:0% +linear some Matrix applied to +B + + align:start position:0% +B + + + align:start position:0% +B +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and now that the reason that helps is + + align:start position:0% +and now that the reason that helps is + + + align:start position:0% +and now that the reason that helps is +that if I'm interested in and as I + + align:start position:0% +that if I'm interested in and as I + + + align:start position:0% +that if I'm interested in and as I +certainly am interested in this Sigma U + + align:start position:0% +certainly am interested in this Sigma U + + + align:start position:0% +certainly am interested in this Sigma U +hat so what's Sigma U hat what's this + + align:start position:0% +hat so what's Sigma U hat what's this + + + align:start position:0% +hat so what's Sigma U hat what's this +what's the covariance Matrix for U hat + + align:start position:0% +what's the covariance Matrix for U hat + + + align:start position:0% +what's the covariance Matrix for U hat +it has to be the expectation of U of the + + align:start position:0% +it has to be the expectation of U of the + + + align:start position:0% +it has to be the expectation of U of the +correct U with no errors minus the U hat + + align:start position:0% +correct U with no errors minus the U hat + + + align:start position:0% +correct U with no errors minus the U hat +which came from B that included errors + + align:start position:0% +which came from B that included errors + + + align:start position:0% +which came from B that included errors +oops not the transpose there if I want I + + align:start position:0% +oops not the transpose there if I want I + + + align:start position:0% +oops not the transpose there if I want I +want a column times a row so that I get + + align:start position:0% +want a column times a row so that I get + + + align:start position:0% +want a column times a row so that I get +a + + align:start position:0% + + + + align:start position:0% + +matrix + + align:start position:0% +matrix + + + align:start position:0% +matrix +good + + align:start position:0% + + + + align:start position:0% + +okay now can I just see what's going on + + align:start position:0% +okay now can I just see what's going on + + + align:start position:0% +okay now can I just see what's going on +here I claim that this is this is my + + align:start position:0% +here I claim that this is this is my + + + align:start position:0% +here I claim that this is this is my +error in + + align:start position:0% +error in + + + align:start position:0% +error in +U and the error in U is related to the + + align:start position:0% +U and the error in U is related to the + + + align:start position:0% +U and the error in U is related to the +error in B by L so this I I I would like + + align:start position:0% +error in B by L so this I I I would like + + + align:start position:0% +error in B by L so this I I I would like +to see as the expected value of + + align:start position:0% +to see as the expected value of + + + align:start position:0% +to see as the expected value of +l + + align:start position:0% +l + + + align:start position:0% +l +etimes l e trans + + align:start position:0% + + + + align:start position:0% + +transpose right to go from from my + + align:start position:0% +transpose right to go from from my + + + align:start position:0% +transpose right to go from from my +inputs to my + + align:start position:0% +inputs to my + + + align:start position:0% +inputs to my +outputs to go from B to U hat I'm + + align:start position:0% +outputs to go from B to U hat I'm + + + align:start position:0% +outputs to go from B to U hat I'm +multiplying by + + align:start position:0% +multiplying by + + + align:start position:0% +multiplying by +L what happens to the to the error + + align:start position:0% +L what happens to the to the error + + + align:start position:0% +L what happens to the to the error +covariance Matrix when I multiply by L + + align:start position:0% +covariance Matrix when I multiply by L + + + align:start position:0% +covariance Matrix when I multiply by L +okay so that well the point is that when + + align:start position:0% +okay so that well the point is that when + + + align:start position:0% +okay so that well the point is that when +I remembering this is an expectation of + + align:start position:0% +I remembering this is an expectation of + + + align:start position:0% +I remembering this is an expectation of +something I'm multiplying + + align:start position:0% +something I'm multiplying + + + align:start position:0% +something I'm multiplying +it's it's the the the sample values + + align:start position:0% +it's it's the the the sample values + + + align:start position:0% +it's it's the the the sample values +times the probability of that sample but + + align:start position:0% +times the probability of that sample but + + + align:start position:0% +times the probability of that sample but +everything here is linear and L is a + + align:start position:0% +everything here is linear and L is a + + + align:start position:0% +everything here is linear and L is a +fixed Matrix so I can bring it out this + + align:start position:0% +fixed Matrix so I can bring it out this + + + align:start position:0% +fixed Matrix so I can bring it out this +is + + align:start position:0% +is + + + align:start position:0% +is +L bringing out on the left expected + + align:start position:0% +L bringing out on the left expected + + + align:start position:0% +L bringing out on the left expected +value of e + + align:start position:0% +value of e + + + align:start position:0% +value of e +transpose times L transpose do you see + + align:start position:0% +transpose times L transpose do you see + + + align:start position:0% +transpose times L transpose do you see +that I just the usual parentheses that's + + align:start position:0% +that I just the usual parentheses that's + + + align:start position:0% +that I just the usual parentheses that's +l e e transpose + + align:start position:0% +l e e transpose + + + align:start position:0% +l e e transpose +looks like a cross word puzzle L + + align:start position:0% +looks like a cross word puzzle L + + + align:start position:0% +looks like a cross word puzzle L +transpose okay so all I'm saying is I + + align:start position:0% +transpose okay so all I'm saying is I + + + align:start position:0% +transpose okay so all I'm saying is I +can bring the L and the L transpose out + + align:start position:0% +can bring the L and the L transpose out + + + align:start position:0% +can bring the L and the L transpose out +of the expectation because when I + + align:start position:0% +of the expectation because when I + + + align:start position:0% +of the expectation because when I +multiply these values by + + align:start position:0% +multiply these values by + + + align:start position:0% +multiply these values by +probabilities L is + + align:start position:0% +probabilities L is + + + align:start position:0% +probabilities L is +fixed L is the same okay and what's this + + align:start position:0% +fixed L is the same okay and what's this + + + align:start position:0% +fixed L is the same okay and what's this +here that's Sigma that's Sigma B so this + + align:start position:0% +here that's Sigma that's Sigma B so this + + + align:start position:0% +here that's Sigma that's Sigma B so this +is Sigma B okay + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +actually + + align:start position:0% +actually + + + align:start position:0% +actually +um it's our no wait a minute we could + + align:start position:0% +um it's our no wait a minute we could + + + align:start position:0% +um it's our no wait a minute we could +figure out what this is we we know what + + align:start position:0% +figure out what this is we we know what + + + align:start position:0% +figure out what this is we we know what +L is now this is where I + + align:start position:0% +L is now this is where I + + + align:start position:0% +L is now this is where I +feel like a bit of ma a typical bit of + + align:start position:0% +feel like a bit of ma a typical bit of + + + align:start position:0% +feel like a bit of ma a typical bit of +magic in these formulas is going to + + align:start position:0% +magic in these formulas is going to + + + align:start position:0% +magic in these formulas is going to +happen now I'm going to put in this + + align:start position:0% +happen now I'm going to put in this + + + align:start position:0% +happen now I'm going to put in this +awful expression for L and see what I + + align:start position:0% +awful expression for L and see what I + + + align:start position:0% +awful expression for L and see what I +get + + align:start position:0% + + + + align:start position:0% + +what I'm doing now is totally standard + + align:start position:0% +what I'm doing now is totally standard + + + align:start position:0% +what I'm doing now is totally standard +and and maybe familiar to all of you but + + align:start position:0% +and and maybe familiar to all of you but + + + align:start position:0% +and and maybe familiar to all of you but +I think I better take this last step can + + align:start position:0% +I think I better take this last step can + + + align:start position:0% +I think I better take this last step can +I just say okay I'm claiming that this + + align:start position:0% +I just say okay I'm claiming that this + + + align:start position:0% +I just say okay I'm claiming that this +is the right L to choose well gaus said + + align:start position:0% +is the right L to choose well gaus said + + + align:start position:0% +is the right L to choose well gaus said +it was so who's going to argue with gal + + align:start position:0% +it was so who's going to argue with gal + + + align:start position:0% +it was so who's going to argue with gal +okay so there's he he says that the + + align:start position:0% +okay so there's he he says that the + + + align:start position:0% +okay so there's he he says that the +right L to take is Sigma is the right C + + align:start position:0% +right L to take is Sigma is the right C + + + align:start position:0% +right L to take is Sigma is the right C +to take is is Sigma B inverse Okay so + + align:start position:0% +to take is is Sigma B inverse Okay so + + + align:start position:0% +to take is is Sigma B inverse Okay so +can I put that l in here could you do + + align:start position:0% +can I put that l in here could you do + + + align:start position:0% +can I put that l in here could you do +that multiplication and do you know what + + align:start position:0% +that multiplication and do you know what + + + align:start position:0% +that multiplication and do you know what +we're going to get I'll make a little + + align:start position:0% +we're going to get I'll make a little + + + align:start position:0% +we're going to get I'll make a little +room to do it because L is a little long + + align:start position:0% + + + + align:start position:0% + +but okay here comes L okay so so I have + + align:start position:0% +but okay here comes L okay so so I have + + + align:start position:0% +but okay here comes L okay so so I have +a transpose Sigma inverse a all + + align:start position:0% +a transpose Sigma inverse a all + + + align:start position:0% +a transpose Sigma inverse a all +inverse times a transpose Sigma inverse + + align:start position:0% +inverse times a transpose Sigma inverse + + + align:start position:0% +inverse times a transpose Sigma inverse +that was the that's the L finally okay + + align:start position:0% +that was the that's the L finally okay + + + align:start position:0% +that was the that's the L finally okay +okay now comes the sigma Sigma I'll just + + align:start position:0% +okay now comes the sigma Sigma I'll just + + + align:start position:0% +okay now comes the sigma Sigma I'll just +write Sigma skip the B time Sigma and + + align:start position:0% +write Sigma skip the B time Sigma and + + + align:start position:0% +write Sigma skip the B time Sigma and +now comes I need more room for L + + align:start position:0% +now comes I need more room for L + + + align:start position:0% +now comes I need more room for L +transpose + + align:start position:0% +transpose + + + align:start position:0% +transpose +okay this formula will finish before the + + align:start position:0% +okay this formula will finish before the + + + align:start position:0% +okay this formula will finish before the +board + + align:start position:0% + + + + align:start position:0% + +does now that was L can I what's L + + align:start position:0% +does now that was L can I what's L + + + align:start position:0% +does now that was L can I what's L +transpose Sigma by the way of course is + + align:start position:0% +transpose Sigma by the way of course is + + + align:start position:0% +transpose Sigma by the way of course is +symmetric Sigma of course is + + align:start position:0% +symmetric Sigma of course is + + + align:start position:0% +symmetric Sigma of course is +symmetric so when I transpose I don't + + align:start position:0% +symmetric so when I transpose I don't + + + align:start position:0% +symmetric so when I transpose I don't +have to worry about transposing Sigma a + + align:start position:0% +have to worry about transposing Sigma a + + + align:start position:0% +have to worry about transposing Sigma a +of course I do have to and this + + align:start position:0% +of course I do have to and this + + + align:start position:0% +of course I do have to and this +combination is symmetric so I + + align:start position:0% +combination is symmetric so I + + + align:start position:0% +combination is symmetric so I +transposing that no no effect okay so + + align:start position:0% +transposing that no no effect okay so + + + align:start position:0% +transposing that no no effect okay so +now I want to transpose this whole thing + + align:start position:0% +now I want to transpose this whole thing + + + align:start position:0% +now I want to transpose this whole thing +in the opposite order so I transpose + + align:start position:0% +in the opposite order so I transpose + + + align:start position:0% +in the opposite order so I transpose +that it's just Sigma inverse transpose + + align:start position:0% +that it's just Sigma inverse transpose + + + align:start position:0% +that it's just Sigma inverse transpose +that it's an a transpose that that's + + align:start position:0% +that it's an a transpose that that's + + + align:start position:0% +that it's an a transpose that that's +symmetric so it doesn't change a + + align:start position:0% +symmetric so it doesn't change a + + + align:start position:0% +symmetric so it doesn't change a +transpose Sigma inverse a inverse and + + align:start position:0% +transpose Sigma inverse a inverse and + + + align:start position:0% +transpose Sigma inverse a inverse and +what have I got + + align:start position:0% + + + + align:start position:0% + +so this is following all the rules and + + align:start position:0% +so this is following all the rules and + + + align:start position:0% +so this is following all the rules and +notice well there's a sigma inverse + + align:start position:0% +notice well there's a sigma inverse + + + align:start position:0% +notice well there's a sigma inverse +Sigma identity in the middle there then + + align:start position:0% +Sigma identity in the middle there then + + + align:start position:0% +Sigma identity in the middle there then +there's an a transpose Sigma inverse a + + align:start position:0% +there's an a transpose Sigma inverse a + + + align:start position:0% +there's an a transpose Sigma inverse a +which I'll just put parentheses around + + align:start position:0% +which I'll just put parentheses around + + + align:start position:0% +which I'll just put parentheses around +to call attention and what do I have + + align:start position:0% +to call attention and what do I have + + + align:start position:0% +to call attention and what do I have +I've got this inverse times this thing + + align:start position:0% +I've got this inverse times this thing + + + align:start position:0% +I've got this inverse times this thing +times the inverse again so so this + + align:start position:0% +times the inverse again so so this + + + align:start position:0% +times the inverse again so so this +knocked off this and left me just with + + align:start position:0% +knocked off this and left me just with + + + align:start position:0% +knocked off this and left me just with +this is it all right if I just + + align:start position:0% +this is it all right if I just + + + align:start position:0% +this is it all right if I just +that's the answer what a beautiful + + align:start position:0% +that's the answer what a beautiful + + + align:start position:0% +that's the answer what a beautiful +answer that the the right choice of + + align:start position:0% +answer that the the right choice of + + + align:start position:0% +answer that the the right choice of +Sigma the right choice of the sorry the + + align:start position:0% +Sigma the right choice of the sorry the + + + align:start position:0% +Sigma the right choice of the sorry the +right choice of the waiting Matrix + + align:start position:0% +right choice of the waiting Matrix + + + align:start position:0% +right choice of the waiting Matrix +produced a beautiful answer for the uh + + align:start position:0% +produced a beautiful answer for the uh + + + align:start position:0% +produced a beautiful answer for the uh +variance in the in the in the uh hat and + + align:start position:0% +variance in the in the in the uh hat and + + + align:start position:0% +variance in the in the in the uh hat and +the Beautiful answer is this is the + + align:start position:0% +the Beautiful answer is this is the + + + align:start position:0% +the Beautiful answer is this is the +inverse is p is our + + align:start position:0% + + + + align:start position:0% + +P that's theu Matrix then in fact that's + + align:start position:0% +P that's theu Matrix then in fact that's + + + align:start position:0% +P that's theu Matrix then in fact that's +like the most important thing output so + + align:start position:0% +like the most important thing output so + + + align:start position:0% +like the most important thing output so +that that the most important output is + + align:start position:0% +that that the most important output is + + + align:start position:0% +that that the most important output is +that uh Sigma U hat which we finally + + align:start position:0% +that uh Sigma U hat which we finally + + + align:start position:0% +that uh Sigma U hat which we finally +identified + + align:start position:0% +identified + + + align:start position:0% +identified +as as Sigma U hat we finally identified + + align:start position:0% +as as Sigma U hat we finally identified + + + align:start position:0% +as as Sigma U hat we finally identified +as our Matrix + + align:start position:0% +as our Matrix + + + align:start position:0% +as our Matrix +p is that + + align:start position:0% +p is that + + + align:start position:0% +p is that +right let's see uh I didn't yes sorry I + + align:start position:0% +right let's see uh I didn't yes sorry I + + + align:start position:0% +right let's see uh I didn't yes sorry I +didn't this was wrong just un + + align:start position:0% +didn't this was wrong just un + + + align:start position:0% +didn't this was wrong just un +fortunately I I get to erase it I meant + + align:start position:0% +fortunately I I get to erase it I meant + + + align:start position:0% +fortunately I I get to erase it I meant +P to be exactly this Matrix that we're + + align:start position:0% +P to be exactly this Matrix that we're + + + align:start position:0% +P to be exactly this Matrix that we're +sorry The crucial Matrix for us p + + align:start position:0% +sorry The crucial Matrix for us p + + + align:start position:0% +sorry The crucial Matrix for us p +is is a transpose Sigma B inverse a all + + align:start position:0% +is is a transpose Sigma B inverse a all + + + align:start position:0% +is is a transpose Sigma B inverse a all +inverse + + align:start position:0% +inverse + + + align:start position:0% +inverse +that's that's the key that's the + + align:start position:0% +that's that's the key that's the + + + align:start position:0% +that's that's the key that's the +beautiful Matrix in the whole subject + + align:start position:0% +beautiful Matrix in the whole subject + + + align:start position:0% +beautiful Matrix in the whole subject +and oh I can't help saying this is this + + align:start position:0% +and oh I can't help saying this is this + + + align:start position:0% +and oh I can't help saying this is this +is the inverse of our stiffness Matrix + + align:start position:0% +is the inverse of our stiffness Matrix + + + align:start position:0% +is the inverse of our stiffness Matrix +those early lectures were + + align:start position:0% +those early lectures were + + + align:start position:0% +those early lectures were +about this Matrix right and its + + align:start position:0% +about this Matrix right and its + + + align:start position:0% +about this Matrix right and its +inverse and now we're meeting it as the + + align:start position:0% +inverse and now we're meeting it as the + + + align:start position:0% +inverse and now we're meeting it as the +central output that the inverse of the + + align:start position:0% +central output that the inverse of the + + + align:start position:0% +central output that the inverse of the +stiffness Matrix as the central output + + align:start position:0% +stiffness Matrix as the central output + + + align:start position:0% +stiffness Matrix as the central output +Sigma U hat the it's the variance of the + + align:start position:0% +Sigma U hat the it's the variance of the + + + align:start position:0% +Sigma U hat the it's the variance of the +error in our uh estimated + + align:start position:0% +error in our uh estimated + + + align:start position:0% +error in our uh estimated +parameters it's it's + + align:start position:0% +parameters it's it's + + + align:start position:0% +parameters it's it's +fantastic and + + align:start position:0% +fantastic and + + + align:start position:0% +fantastic and +there's one more Central + + align:start position:0% +there's one more Central + + + align:start position:0% +there's one more Central +Point you remember what was special + + align:start position:0% +Point you remember what was special + + + align:start position:0% +Point you remember what was special +about those matrices in the beginning of + + align:start position:0% +about those matrices in the beginning of + + + align:start position:0% +about those matrices in the beginning of +this course of + + align:start position:0% +this course of + + + align:start position:0% +this course of +lectures they were + + align:start position:0% +lectures they were + + + align:start position:0% +lectures they were +triagonal they were Tri diagonal and + + align:start position:0% +triagonal they were Tri diagonal and + + + align:start position:0% +triagonal they were Tri diagonal and +that and that came for the line of + + align:start position:0% +that and that came for the line of + + + align:start position:0% +that and that came for the line of +Springs + + align:start position:0% +Springs + + + align:start position:0% +Springs +because um each spring was just + + align:start position:0% +because um each spring was just + + + align:start position:0% +because um each spring was just +connected to one spring below and one + + align:start position:0% +connected to one spring below and one + + + align:start position:0% +connected to one spring below and one +above + + align:start position:0% +above + + + align:start position:0% +above +but Springs here were not connected to + + align:start position:0% +but Springs here were not connected to + + + align:start position:0% +but Springs here were not connected to +Springs 10 down or we wouldn't have had + + align:start position:0% +Springs 10 down or we wouldn't have had + + + align:start position:0% +Springs 10 down or we wouldn't have had +tridiagonal + + align:start position:0% +tridiagonal + + + align:start position:0% +tridiagonal +matrices all I want to say is that the + + align:start position:0% +matrices all I want to say is that the + + + align:start position:0% +matrices all I want to say is that the +most important word that's not on this + + align:start position:0% +most important word that's not on this + + + align:start position:0% +most important word that's not on this +Blackboard is + + align:start position:0% +Blackboard is + + + align:start position:0% +Blackboard is +tridiagonal that's it's the I'll have to + + align:start position:0% +tridiagonal that's it's the I'll have to + + + align:start position:0% +tridiagonal that's it's the I'll have to +qualify it for for those first lectures + + align:start position:0% +qualify it for for those first lectures + + + align:start position:0% +qualify it for for those first lectures +it was normal triagonal + + align:start position:0% +it was normal triagonal + + + align:start position:0% +it was normal triagonal +matrices now we're going to have blocks + + align:start position:0% +matrices now we're going to have blocks + + + align:start position:0% +matrices now we're going to have blocks +triagonal that's the central thing that + + align:start position:0% +triagonal that's the central thing that + + + align:start position:0% +triagonal that's the central thing that +makes the whole calman filter process + + align:start position:0% +makes the whole calman filter process + + + align:start position:0% +makes the whole calman filter process +work is that the the the key Matrix in + + align:start position:0% +work is that the the the key Matrix in + + + align:start position:0% +work is that the the the key Matrix in +there this Matrix in the in the giant + + align:start position:0% +there this Matrix in the in the giant + + + align:start position:0% +there this Matrix in the in the giant +process is block Tri diagonal that's I + + align:start position:0% +process is block Tri diagonal that's I + + + align:start position:0% +process is block Tri diagonal that's I +can't overemphasize that that's the key + + align:start position:0% +can't overemphasize that that's the key + + + align:start position:0% +can't overemphasize that that's the key +to all the Matrix formulas and to the + + align:start position:0% +to all the Matrix formulas and to the + + + align:start position:0% +to all the Matrix formulas and to the +recursion and to everything that's and + + align:start position:0% +recursion and to everything that's and + + + align:start position:0% +recursion and to everything that's and +and you can see that it's uh lots of + + align:start position:0% +and you can see that it's uh lots of + + + align:start position:0% +and you can see that it's uh lots of +applications are blocked tried diagonal + + align:start position:0% +applications are blocked tried diagonal + + + align:start position:0% +applications are blocked tried diagonal +the new state comes from the old state + + align:start position:0% +the new state comes from the old state + + + align:start position:0% +the new state comes from the old state +but it doesn't come from 10 old + + align:start position:0% +but it doesn't come from 10 old + + + align:start position:0% +but it doesn't come from 10 old +States or it doesn't go all the way back + + align:start position:0% +States or it doesn't go all the way back + + + align:start position:0% +States or it doesn't go all the way back +to the very beginning state it just it's + + align:start position:0% +to the very beginning state it just it's + + + align:start position:0% +to the very beginning state it just it's +connected to the previous state and it's + + align:start position:0% +connected to the previous state and it's + + + align:start position:0% +connected to the previous state and it's +like you know we have a differential + + align:start position:0% +like you know we have a differential + + + align:start position:0% +like you know we have a differential +equation or a difference equation + + align:start position:0% +equation or a difference equation + + + align:start position:0% +equation or a difference equation +connecting new state to old one I I'll + + align:start position:0% +connecting new state to old one I I'll + + + align:start position:0% +connecting new state to old one I I'll +come back to + + align:start position:0% +come back to + + + align:start position:0% +come back to +that in the in the second lecture of + + align:start position:0% +that in the in the second lecture of + + + align:start position:0% +that in the in the second lecture of +course when when we really get to that + + align:start position:0% +course when when we really get to that + + + align:start position:0% +course when when we really get to that +okay I just didn't didn't want + + align:start position:0% +okay I just didn't didn't want + + + align:start position:0% +okay I just didn't didn't want +to all I can what I can try to do in + + align:start position:0% +to all I can what I can try to do in + + + align:start position:0% +to all I can what I can try to do in +these lectures is to + + align:start position:0% +these lectures is to + + + align:start position:0% +these lectures is to +highlight what seems like to me the key + + align:start position:0% +highlight what seems like to me the key + + + align:start position:0% +highlight what seems like to me the key +points we're going to need we're going + + align:start position:0% +points we're going to need we're going + + + align:start position:0% +points we're going to need we're going +to have formulas and I won't get them + + align:start position:0% +to have formulas and I won't get them + + + align:start position:0% +to have formulas and I won't get them +all on the board but um + + align:start position:0% +all on the board but um + + + align:start position:0% +all on the board but um +we but those can be looked up those will + + align:start position:0% +we but those can be looked up those will + + + align:start position:0% +we but those can be looked up those will +be in this chapter that goes on the web + + align:start position:0% +be in this chapter that goes on the web + + + align:start position:0% +be in this chapter that goes on the web +and and there many other descriptions of + + align:start position:0% +and and there many other descriptions of + + + align:start position:0% +and and there many other descriptions of +them in the references and I have begun + + align:start position:0% +them in the references and I have begun + + + align:start position:0% +them in the references and I have begun +to give all the + + align:start position:0% +to give all the + + + align:start position:0% +to give all the +references uh but the ideas are always + + align:start position:0% +references uh but the ideas are always + + + align:start position:0% +references uh but the ideas are always +not so many and one of them is block + + align:start position:0% +not so many and one of them is block + + + align:start position:0% +not so many and one of them is block +triagonal they're blocks + + align:start position:0% + + + + align:start position:0% + +because + + align:start position:0% +because + + + align:start position:0% +because +B new the new the new uh uh in this + + align:start position:0% +B new the new the new uh uh in this + + + align:start position:0% +B new the new the new uh uh in this +recursive stuff this is a block of bees + + align:start position:0% +recursive stuff this is a block of bees + + + align:start position:0% +recursive stuff this is a block of bees +this is another block of B's this is a + + align:start position:0% +this is another block of B's this is a + + + align:start position:0% +this is another block of B's this is a +block of a this is the rest of a the + + align:start position:0% +block of a this is the rest of a the + + + align:start position:0% +block of a this is the rest of a the +this is the block picture do you want me + + align:start position:0% +this is the block picture do you want me + + + align:start position:0% +this is the block picture do you want me +to write that as a block + + align:start position:0% + + + + align:start position:0% + +picture it's the block Matrix is a old a + + align:start position:0% +picture it's the block Matrix is a old a + + + align:start position:0% +picture it's the block Matrix is a old a +new and it multiplies U and the U is not + + align:start position:0% +new and it multiplies U and the U is not + + + align:start position:0% +new and it multiplies U and the U is not +changing length if we have a newer and a + + align:start position:0% +changing length if we have a newer and a + + + align:start position:0% +changing length if we have a newer and a +newer and a brand new Block in the + + align:start position:0% +newer and a brand new Block in the + + + align:start position:0% +newer and a brand new Block in the +recursive setup we're still keeping the + + align:start position:0% +recursive setup we're still keeping the + + + align:start position:0% +recursive setup we're still keeping the +same u in the calman setup we're also + + align:start position:0% +same u in the calman setup we're also + + + align:start position:0% +same u in the calman setup we're also +getting a new U and a newer U and a + + align:start position:0% +getting a new U and a newer U and a + + + align:start position:0% +getting a new U and a newer U and a +brand new U so that's the difference + + align:start position:0% +brand new U so that's the difference + + + align:start position:0% +brand new U so that's the difference +here that + + align:start position:0% +here that + + + align:start position:0% +here that +recursive uh you could say it in Matrix + + align:start position:0% +recursive uh you could say it in Matrix + + + align:start position:0% +recursive uh you could say it in Matrix +language recursively squares we're + + align:start position:0% +language recursively squares we're + + + align:start position:0% +language recursively squares we're +adding new + + align:start position:0% + + + + align:start position:0% + +rows in Dynamic problems we're adding + + align:start position:0% +rows in Dynamic problems we're adding + + + align:start position:0% +rows in Dynamic problems we're adding +new parameters so we're adding new + + align:start position:0% +new parameters so we're adding new + + + align:start position:0% +new parameters so we're adding new +columns too so we're adding new rows and + + align:start position:0% +columns too so we're adding new rows and + + + align:start position:0% +columns too so we're adding new rows and +columns so should I write that down to + + align:start position:0% +columns so should I write that down to + + + align:start position:0% +columns so should I write that down to +get it on the board recursive this stuff + + align:start position:0% +get it on the board recursive this stuff + + + align:start position:0% +get it on the board recursive this stuff +is new rows new rows in + + align:start position:0% +is new rows new rows in + + + align:start position:0% +is new rows new rows in +a and the Dynamics is + + align:start position:0% +a and the Dynamics is + + + align:start position:0% +a and the Dynamics is +new columns + + align:start position:0% +new columns + + + align:start position:0% +new columns +to new + + align:start position:0% +to new + + + align:start position:0% +to new +unknowns okay but this lecture is about + + align:start position:0% +unknowns okay but this lecture is about + + + align:start position:0% +unknowns okay but this lecture is about +new rows is about this problem is about + + align:start position:0% +new rows is about this problem is about + + + align:start position:0% +new rows is about this problem is about +this problem so now I'm ready to turn to + + align:start position:0% +this problem so now I'm ready to turn to + + + align:start position:0% +this problem so now I'm ready to turn to +that problem but first I didn't make + + align:start position:0% +that problem but first I didn't make + + + align:start position:0% +that problem but first I didn't make +the most important comment about this + + align:start position:0% +the most important comment about this + + + align:start position:0% +the most important comment about this +I've never written such a long equation + + align:start position:0% +I've never written such a long equation + + + align:start position:0% +I've never written such a long equation +I'm sure as this one for Sigma + + align:start position:0% +I'm sure as this one for Sigma + + + align:start position:0% +I'm sure as this one for Sigma +U which has turned out to be P which + + align:start position:0% +U which has turned out to be P which + + + align:start position:0% +U which has turned out to be P which +turned out to have this NE + + align:start position:0% + + + + align:start position:0% + +answer what's + + align:start position:0% +answer what's + + + align:start position:0% +answer what's +the the point I haven't made but the + + align:start position:0% +the the point I haven't made but the + + + align:start position:0% +the the point I haven't made but the +it's it's uh established in the + + align:start position:0% + + + + align:start position:0% + +textbook is the reason for this Choice + + align:start position:0% +textbook is the reason for this Choice + + + align:start position:0% +textbook is the reason for this Choice +the reason that choice is the right + + align:start position:0% +the reason that choice is the right + + + align:start position:0% +the reason that choice is the right +one is that it + + align:start position:0% +one is that it + + + align:start position:0% +one is that it +makes this Matrix p as small as + + align:start position:0% +makes this Matrix p as small as + + + align:start position:0% +makes this Matrix p as small as +possible we get the best + + align:start position:0% +possible we get the best + + + align:start position:0% +possible we get the best +estimate in the sense that the variance + + align:start position:0% +estimate in the sense that the variance + + + align:start position:0% +estimate in the sense that the variance +is the the the the the variant + + align:start position:0% +is the the the the the variant + + + align:start position:0% +is the the the the the variant +covariance Matrix is as small as + + align:start position:0% +covariance Matrix is as small as + + + align:start position:0% +covariance Matrix is as small as +possible by making this choice of + + align:start position:0% +possible by making this choice of + + + align:start position:0% +possible by making this choice of +Sigma this Choice sorry this choice of C + + align:start position:0% +Sigma this Choice sorry this choice of C + + + align:start position:0% +Sigma this Choice sorry this choice of C +this by taking that particular waiting + + align:start position:0% +this by taking that particular waiting + + + align:start position:0% +this by taking that particular waiting +Matrix it produced this answer and we + + align:start position:0% +Matrix it produced this answer and we + + + align:start position:0% +Matrix it produced this answer and we +couldn't have got a + + align:start position:0% +couldn't have got a + + + align:start position:0% +couldn't have got a +smaller we couldn't have got a smaller + + align:start position:0% +smaller we couldn't have got a smaller + + + align:start position:0% +smaller we couldn't have got a smaller +Sigma U than + + align:start position:0% +Sigma U than + + + align:start position:0% +Sigma U than +that and uh that's uh that's that's one + + align:start position:0% +that and uh that's uh that's that's one + + + align:start position:0% +that and uh that's uh that's that's one +way to say why it's best so there's an + + align:start position:0% +way to say why it's best so there's an + + + align:start position:0% +way to say why it's best so there's an +optimal property of this of this weight + + align:start position:0% +optimal property of this of this weight + + + align:start position:0% +optimal property of this of this weight +and uh that's one way to justify the + + align:start position:0% +and uh that's one way to justify the + + + align:start position:0% +and uh that's one way to justify the +choice of that of that as our waiting + + align:start position:0% +choice of that of that as our waiting + + + align:start position:0% +choice of that of that as our waiting +Matrix + + align:start position:0% +Matrix + + + align:start position:0% +Matrix +okay now + + align:start position:0% +okay now + + + align:start position:0% +okay now +I'm ready to tackle + + align:start position:0% +I'm ready to tackle + + + align:start position:0% +I'm ready to tackle +this this recursion all right so what's + + align:start position:0% +this this recursion all right so what's + + + align:start position:0% +this this recursion all right so what's +the idea we solve the old problem then + + align:start position:0% +the idea we solve the old problem then + + + align:start position:0% +the idea we solve the old problem then +we get new + + align:start position:0% +we get new + + + align:start position:0% +we get new +measurements we + + align:start position:0% +measurements we + + + align:start position:0% +measurements we +have new part of a corresponding new + + align:start position:0% +have new part of a corresponding new + + + align:start position:0% +have new part of a corresponding new +part of the Matrix a and I want to get I + + align:start position:0% +part of the Matrix a and I want to get I + + + align:start position:0% +part of the Matrix a and I want to get I +want to solve the problem + + align:start position:0% +want to solve the problem + + + align:start position:0% +want to solve the problem +again and the point is I want to solve + + align:start position:0% +again and the point is I want to solve + + + align:start position:0% +again and the point is I want to solve +the problem again + + align:start position:0% +the problem again + + + align:start position:0% +the problem again +I don't want to start from the + + align:start position:0% +I don't want to start from the + + + align:start position:0% +I don't want to start from the +beginning that's the that's the + + align:start position:0% +beginning that's the that's the + + + align:start position:0% +beginning that's the that's the +recursive idea I would like to be able + + align:start position:0% +recursive idea I would like to be able + + + align:start position:0% +recursive idea I would like to be able +to say I would like to be able to use my + + align:start position:0% +to say I would like to be able to use my + + + align:start position:0% +to say I would like to be able to use my +the calculation already + + align:start position:0% + + + + align:start position:0% + +made so I would like to have a update + + align:start position:0% +made so I would like to have a update + + + align:start position:0% +made so I would like to have a update +formula of this type I would like to to + + align:start position:0% +formula of this type I would like to to + + + align:start position:0% +formula of this type I would like to to +see the best you for the combined system + + align:start position:0% +see the best you for the combined system + + + align:start position:0% +see the best you for the combined system +as the best you for the original system + + align:start position:0% +as the best you for the original system + + + align:start position:0% +as the best you for the original system +plus some Matrix and that's going to be + + align:start position:0% +plus some Matrix and that's going to be + + + align:start position:0% +plus some Matrix and that's going to be +a key this common gain Matrix + + align:start position:0% +a key this common gain Matrix + + + align:start position:0% +a key this common gain Matrix +multiplying this quantity now does that + + align:start position:0% +multiplying this quantity now does that + + + align:start position:0% +multiplying this quantity now does that +seem like a reasonable goal before we + + align:start position:0% +seem like a reasonable goal before we + + + align:start position:0% +seem like a reasonable goal before we +reach it let's see if it's let's see + + align:start position:0% +reach it let's see if it's let's see + + + align:start position:0% +reach it let's see if it's let's see +what we're aiming for and + + align:start position:0% +what we're aiming for and + + + align:start position:0% +what we're aiming for and +you'll what would happen + + align:start position:0% +you'll what would happen + + + align:start position:0% +you'll what would happen +if what would happen if + + align:start position:0% +if what would happen if + + + align:start position:0% +if what would happen if +this these new measurements were a + + align:start position:0% +this these new measurements were a + + + align:start position:0% +this these new measurements were a +perfect repeat and this was a perfect + + align:start position:0% +perfect repeat and this was a perfect + + + align:start position:0% +perfect repeat and this was a perfect +repeat if if a new was the same as a old + + align:start position:0% +repeat if if a new was the same as a old + + + align:start position:0% +repeat if if a new was the same as a old +and B knew was the same as B old so we + + align:start position:0% +and B knew was the same as B old so we + + + align:start position:0% +and B knew was the same as B old so we +just ran the experiment + + align:start position:0% +just ran the experiment + + + align:start position:0% +just ran the experiment +twice or just copied the answer and + + align:start position:0% +twice or just copied the answer and + + + align:start position:0% +twice or just copied the answer and +didn't notice or something what would we + + align:start position:0% +didn't notice or something what would we + + + align:start position:0% +didn't notice or something what would we +expect you new the the perfect the best + + align:start position:0% +expect you new the the perfect the best + + + align:start position:0% +expect you new the the perfect the best +U to be for the combined system it' be + + align:start position:0% +U to be for the combined system it' be + + + align:start position:0% +U to be for the combined system it' be +the same right and you see that that's + + align:start position:0% +the same right and you see that that's + + + align:start position:0% +the same right and you see that that's +what would happen with this formula that + + align:start position:0% +what would happen with this formula that + + + align:start position:0% +what would happen with this formula that +you new would be U old plus + + align:start position:0% +you new would be U old plus + + + align:start position:0% +you new would be U old plus +this uh would be + + align:start position:0% +this uh would be + + + align:start position:0% +this uh would be +uh uh the best uh is that is that right + + align:start position:0% +uh uh the best uh is that is that right + + + align:start position:0% +uh uh the best uh is that is that right +we would learn if if if well maybe I'm + + align:start position:0% +we would learn if if if well maybe I'm + + + align:start position:0% +we would learn if if if well maybe I'm +saying it a little should be saying it + + align:start position:0% +saying it a little should be saying it + + + align:start position:0% +saying it a little should be saying it +differently yeah that that the best + + align:start position:0% +differently yeah that that the best + + + align:start position:0% +differently yeah that that the best +uh that if our yeah I I should have so I + + align:start position:0% +uh that if our yeah I I should have so I + + + align:start position:0% +uh that if our yeah I I should have so I +have to wipe out part of what I said and + + align:start position:0% +have to wipe out part of what I said and + + + align:start position:0% +have to wipe out part of what I said and +say it differently although what I said + + align:start position:0% +say it differently although what I said + + + align:start position:0% +say it differently although what I said +would apply but what I wanted to say was + + align:start position:0% +would apply but what I wanted to say was + + + align:start position:0% +would apply but what I wanted to say was +if the new measurements exactly if this + + align:start position:0% +if the new measurements exactly if this + + + align:start position:0% +if the new measurements exactly if this +was Zero we wouldn't make a change right + + align:start position:0% +was Zero we wouldn't make a change right + + + align:start position:0% +was Zero we wouldn't make a change right +that's that's you you see what I'm + + align:start position:0% +that's that's you you see what I'm + + + align:start position:0% +that's that's you you see what I'm +struggling for here that that if our old + + align:start position:0% +struggling for here that that if our old + + + align:start position:0% +struggling for here that that if our old +measurements exactly gave us perfection + + align:start position:0% +measurements exactly gave us perfection + + + align:start position:0% +measurements exactly gave us perfection +in this second in this new system then + + align:start position:0% +in this second in this new system then + + + align:start position:0% +in this second in this new system then +we wouldn't want to change of course but + + align:start position:0% +we wouldn't want to change of course but + + + align:start position:0% +we wouldn't want to change of course but +if they don't give us Perfection then + + align:start position:0% +if they don't give us Perfection then + + + align:start position:0% +if they don't give us Perfection then +this is called The Innovation this is + + align:start position:0% +this is called The Innovation this is + + + align:start position:0% +this is called The Innovation this is +the new + + align:start position:0% +the new + + + align:start position:0% +the new +information this is the Ovation + + align:start position:0% +information this is the Ovation + + + align:start position:0% +information this is the Ovation +here and + + align:start position:0% +here and + + + align:start position:0% +here and +uh and we hope that there should be some + + align:start position:0% +uh and we hope that there should be some + + + align:start position:0% +uh and we hope that there should be some +Matrix that multiplies that Innovation + + align:start position:0% +Matrix that multiplies that Innovation + + + align:start position:0% +Matrix that multiplies that Innovation +to give us the the Delta you hat the the + + align:start position:0% +to give us the the Delta you hat the the + + + align:start position:0% +to give us the the Delta you hat the the +correction okay could we just derive + + align:start position:0% +correction okay could we just derive + + + align:start position:0% +correction okay could we just derive +this + + align:start position:0% +this + + + align:start position:0% +this +formula that's that's what I plan to do + + align:start position:0% +formula that's that's what I plan to do + + + align:start position:0% +formula that's that's what I plan to do +now is just derive it from first + + align:start position:0% +now is just derive it from first + + + align:start position:0% +now is just derive it from first +principles what do I mean by first + + align:start position:0% +principles what do I mean by first + + + align:start position:0% +principles what do I mean by first +principles I mean that I'll I'll write + + align:start position:0% +principles I mean that I'll I'll write + + + align:start position:0% +principles I mean that I'll I'll write +the the answer to this + + align:start position:0% +the the answer to this + + + align:start position:0% +the the answer to this +problem and then I'll manipulate + + align:start position:0% +problem and then I'll manipulate + + + align:start position:0% +problem and then I'll manipulate +to put it in this form is that all right + + align:start position:0% +to put it in this form is that all right + + + align:start position:0% +to put it in this form is that all right +that's so that's the goal so what's the + + align:start position:0% +that's so that's the goal so what's the + + + align:start position:0% +that's so that's the goal so what's the +answer to this + + align:start position:0% +answer to this + + + align:start position:0% +answer to this +problem + + align:start position:0% +problem + + + align:start position:0% +problem +okay so we see the we see the problem + + align:start position:0% +okay so we see the we see the problem + + + align:start position:0% +okay so we see the we see the problem +here and we know the equation that we + + align:start position:0% +here and we know the equation that we + + + align:start position:0% +here and we know the equation that we +have to solve and we've decided that + + align:start position:0% +have to solve and we've decided that + + + align:start position:0% +have to solve and we've decided that +Sigma will separate into two pieces + + align:start position:0% +Sigma will separate into two pieces + + + align:start position:0% +Sigma will separate into two pieces +that's you'll see that that's a big help + + align:start position:0% +that's you'll see that that's a big help + + + align:start position:0% +that's you'll see that that's a big help +so actually what is this + + align:start position:0% +so actually what is this + + + align:start position:0% +so actually what is this +left hand side Matrix for this for this + + align:start position:0% +left hand side Matrix for this for this + + + align:start position:0% +left hand side Matrix for this for this +problem yeah let me let me do this in + + align:start position:0% +problem yeah let me let me do this in + + + align:start position:0% +problem yeah let me let me do this in +two steps here + + align:start position:0% + + + + align:start position:0% + +okay okay so I'm about to derive this + + align:start position:0% +okay okay so I'm about to derive this + + + align:start position:0% +okay okay so I'm about to derive this +this + + align:start position:0% +this + + + align:start position:0% +this +uh this + + align:start position:0% +uh this + + + align:start position:0% +uh this +formula + + align:start position:0% + + + + align:start position:0% + +okay okay so I've got a whole lot of + + align:start position:0% +okay okay so I've got a whole lot of + + + align:start position:0% +okay okay so I've got a whole lot of +pieces here I've got this Matrix and + + align:start position:0% +pieces here I've got this Matrix and + + + align:start position:0% +pieces here I've got this Matrix and +then I've got some changes over here let + + align:start position:0% +then I've got some changes over here let + + + align:start position:0% +then I've got some changes over here let +me deal with that Matrix first so I have + + align:start position:0% +me deal with that Matrix first so I have + + + align:start position:0% +me deal with that Matrix first so I have +a which + + align:start position:0% +a which + + + align:start position:0% +a which +is a old a + + align:start position:0% + + + + align:start position:0% + +new times Sigma inverse which is Sigma + + align:start position:0% +new times Sigma inverse which is Sigma + + + align:start position:0% +new times Sigma inverse which is Sigma +old inverse Sigma new inverse you see + + align:start position:0% +old inverse Sigma new inverse you see + + + align:start position:0% +old inverse Sigma new inverse you see +there it was absolutely critical that we + + align:start position:0% +there it was absolutely critical that we + + + align:start position:0% +there it was absolutely critical that we +had a block diagonal matrix and now a + + align:start position:0% +had a block diagonal matrix and now a + + + align:start position:0% +had a block diagonal matrix and now a +transpose is a + + align:start position:0% +transpose is a + + + align:start position:0% +transpose is a +old transpose + + align:start position:0% +old transpose + + + align:start position:0% +old transpose +next to a new + + align:start position:0% +next to a new + + + align:start position:0% +next to a new +transpose + + align:start position:0% + + + + align:start position:0% + +good all I'm finding here oh yeah all + + align:start position:0% +good all I'm finding here oh yeah all + + + align:start position:0% +good all I'm finding here oh yeah all +right let's just do that multiplication + + align:start position:0% +right let's just do that multiplication + + + align:start position:0% +right let's just do that multiplication +out so so what do I what do I have then + + align:start position:0% +out so so what do I what do I have then + + + align:start position:0% +out so so what do I what do I have then +I've just got a sigma inverse a + + align:start position:0% +I've just got a sigma inverse a + + + align:start position:0% +I've just got a sigma inverse a +transpose old maybe I maybe I if I'm + + align:start position:0% +transpose old maybe I maybe I if I'm + + + align:start position:0% +transpose old maybe I maybe I if I'm +consistent I write old on every + + align:start position:0% +consistent I write old on every + + + align:start position:0% +consistent I write old on every +Matrix Plus + + align:start position:0% +Matrix Plus + + + align:start position:0% +Matrix Plus +doing that multiplication oh plus a new + + align:start position:0% +doing that multiplication oh plus a new + + + align:start position:0% +doing that multiplication oh plus a new +let me write the answer down what it's + + align:start position:0% +let me write the answer down what it's + + + align:start position:0% +let me write the answer down what it's +maybe not Sigma inverse + + align:start position:0% +maybe not Sigma inverse + + + align:start position:0% +maybe not Sigma inverse +new a + + align:start position:0% +new a + + + align:start position:0% +new a +new do you see + + align:start position:0% + + + + align:start position:0% + +that a am I am I doing this + + align:start position:0% +that a am I am I doing this + + + align:start position:0% +that a am I am I doing this +right am I the transpose should have + + align:start position:0% +right am I the transpose should have + + + align:start position:0% +right am I the transpose should have +been first shouldn't it yeah absolutely + + align:start position:0% +been first shouldn't it yeah absolutely + + + align:start position:0% +been first shouldn't it yeah absolutely +otherwise all wrong + + align:start position:0% +otherwise all wrong + + + align:start position:0% +otherwise all wrong +thanks you're quite + + align:start position:0% +thanks you're quite + + + align:start position:0% +thanks you're quite +right I can't say that I make errors + + align:start position:0% +right I can't say that I make errors + + + align:start position:0% +right I can't say that I make errors +just to keep you awake but uh you can + + align:start position:0% +just to keep you awake but uh you can + + + align:start position:0% +just to keep you awake but uh you can +see I + + align:start position:0% +see I + + + align:start position:0% +see I +right well yeah but I like to go on + + align:start position:0% +right well yeah but I like to go on + + + align:start position:0% +right well yeah but I like to go on +record with the truth here uh all right + + align:start position:0% +record with the truth here uh all right + + + align:start position:0% +record with the truth here uh all right +and and of course I was going to see + + align:start position:0% +and and of course I was going to see + + + align:start position:0% +and and of course I was going to see +that it was that I was wrong just as + + align:start position:0% +that it was that I was wrong just as + + + align:start position:0% +that it was that I was wrong just as +soon as I tried that multiplications so + + align:start position:0% +soon as I tried that multiplications so + + + align:start position:0% +soon as I tried that multiplications so +you're absolutely right it's a transpose + + align:start position:0% +you're absolutely right it's a transpose + + + align:start position:0% +you're absolutely right it's a transpose +old and a transpose + + align:start position:0% +old and a transpose + + + align:start position:0% +old and a transpose +new that's a transpose put together this + + align:start position:0% +new that's a transpose put together this + + + align:start position:0% +new that's a transpose put together this +is Sigma inverse and this is a good now + + align:start position:0% +is Sigma inverse and this is a good now + + + align:start position:0% +is Sigma inverse and this is a good now +I believe this multiplication do you + + align:start position:0% +I believe this multiplication do you + + + align:start position:0% +I believe this multiplication do you +believe + + align:start position:0% + + + + align:start position:0% + +it and do you see what + + align:start position:0% +it and do you see what + + + align:start position:0% +it and do you see what +it's I mean it's quite important to see + + align:start position:0% +it's I mean it's quite important to see + + + align:start position:0% +it's I mean it's quite important to see +what happens because this is like the + + align:start position:0% +what happens because this is like the + + + align:start position:0% +what happens because this is like the +whole point of the lecture we're getting + + align:start position:0% +whole point of the lecture we're getting + + + align:start position:0% +whole point of the lecture we're getting +new new stuff here yeah + + align:start position:0% + + + + align:start position:0% + +yeah this you're right of course I + + align:start position:0% +yeah this you're right of course I + + + align:start position:0% +yeah this you're right of course I +didn't correct the last line either + + align:start position:0% +didn't correct the last line either + + + align:start position:0% +didn't correct the last line either +thanks it's a gosh I'm living and dying + + align:start position:0% +thanks it's a gosh I'm living and dying + + + align:start position:0% +thanks it's a gosh I'm living and dying +with a transpose CA here I ought to get + + align:start position:0% +with a transpose CA here I ought to get + + + align:start position:0% +with a transpose CA here I ought to get +the transpose in the right spot there we + + align:start position:0% +the transpose in the right spot there we + + + align:start position:0% +the transpose in the right spot there we +go is that all right + + align:start position:0% +go is that all right + + + align:start position:0% +go is that all right +now yeah + + align:start position:0% + + + + align:start position:0% + +yeah + + align:start position:0% +yeah + + + align:start position:0% +yeah +you actually the way I would see this + + align:start position:0% +you actually the way I would see this + + + align:start position:0% +you actually the way I would see this +is uh my old columns times + + align:start position:0% +is uh my old columns times + + + align:start position:0% +is uh my old columns times +rows I mean if suppose a new is just one + + align:start position:0% +rows I mean if suppose a new is just one + + + align:start position:0% +rows I mean if suppose a new is just one +new a suppose a new is just one new row + + align:start position:0% +new a suppose a new is just one new row + + + align:start position:0% +new a suppose a new is just one new row +this is like valuable to think of one + + align:start position:0% +this is like valuable to think of one + + + align:start position:0% +this is like valuable to think of one +new measurement has come in so we have + + align:start position:0% +new measurement has come in so we have + + + align:start position:0% +new measurement has come in so we have +one new row of a one new column of a + + align:start position:0% +one new row of a one new column of a + + + align:start position:0% +one new row of a one new column of a +transpose how much does that change this + + align:start position:0% +transpose how much does that change this + + + align:start position:0% +transpose how much does that change this +a transpose Sigma inverse a it changes + + align:start position:0% +a transpose Sigma inverse a it changes + + + align:start position:0% +a transpose Sigma inverse a it changes +us just by the column times the row + + align:start position:0% +us just by the column times the row + + + align:start position:0% +us just by the column times the row +times it would just be a one by one + + align:start position:0% +times it would just be a one by one + + + align:start position:0% +times it would just be a one by one +number in in in what I just described + + align:start position:0% +number in in in what I just described + + + align:start position:0% +number in in in what I just described +you see I'm multiplying + + align:start position:0% +you see I'm multiplying + + + align:start position:0% +you see I'm multiplying +columns by piece by matrix by + + align:start position:0% +columns by piece by matrix by + + + align:start position:0% +columns by piece by matrix by +row and It just fits okay so that's the + + align:start position:0% +row and It just fits okay so that's the + + + align:start position:0% +row and It just fits okay so that's the +that's the uh uh that's the the + + align:start position:0% +that's the uh uh that's the the + + + align:start position:0% +that's the uh uh that's the the +total okay you see all right I that that + + align:start position:0% +total okay you see all right I that that + + + align:start position:0% +total okay you see all right I that that +better be okay because I've got uh uh + + align:start position:0% +better be okay because I've got uh uh + + + align:start position:0% +better be okay because I've got uh uh +now all right now so I'm going to have + + align:start position:0% +now all right now so I'm going to have + + + align:start position:0% +now all right now so I'm going to have +to You'll forgive me if I if I depend on + + align:start position:0% +to You'll forgive me if I if I depend on + + + align:start position:0% +to You'll forgive me if I if I depend on +the author for help here + + align:start position:0% +the author for help here + + + align:start position:0% +the author for help here +okay + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +okay right okay now let's see let + + align:start position:0% +okay right okay now let's see let + + + align:start position:0% +okay right okay now let's see let +me so here I'm talking about the this + + align:start position:0% +me so here I'm talking about the this + + + align:start position:0% +me so here I'm talking about the this +will leave to an update of U hat this + + align:start position:0% +will leave to an update of U hat this + + + align:start position:0% +will leave to an update of U hat this +update of U but I haven't written in can + + align:start position:0% +update of U but I haven't written in can + + + align:start position:0% +update of U but I haven't written in can +you maybe tell me what it is what's the + + align:start position:0% +you maybe tell me what it is what's the + + + align:start position:0% +you maybe tell me what it is what's the +update formula for + + align:start position:0% +update formula for + + + align:start position:0% +update formula for +p the the two outputs are U hat and + + align:start position:0% +p the the two outputs are U hat and + + + align:start position:0% +p the the two outputs are U hat and +P and we're looking and we're going to + + align:start position:0% +P and we're looking and we're going to + + + align:start position:0% +P and we're looking and we're going to +write down the right expression here for + + align:start position:0% +write down the right expression here for + + + align:start position:0% +write down the right expression here for +the update in U but we darn well have to + + align:start position:0% +the update in U but we darn well have to + + + align:start position:0% +the update in U but we darn well have to +be able to write down the right + + align:start position:0% +be able to write down the right + + + align:start position:0% +be able to write down the right +expression for the up state in + + align:start position:0% +expression for the up state in + + + align:start position:0% +expression for the up state in +p and what's that what's the new P + + align:start position:0% +p and what's that what's the new P + + + align:start position:0% +p and what's that what's the new P +what's the new Sigma you have what's + + align:start position:0% +what's the new Sigma you have what's + + + align:start position:0% +what's the new Sigma you have what's +here here here's here's P well this is a + + align:start position:0% +here here here's here's P well this is a + + + align:start position:0% +here here here's here's P well this is a +case where it'll be easier to write the + + align:start position:0% +case where it'll be easier to write the + + + align:start position:0% +case where it'll be easier to write the +update in P inverse in in this Matrix + + align:start position:0% +update in P inverse in in this Matrix + + + align:start position:0% +update in P inverse in in this Matrix +without the + + align:start position:0% +without the + + + align:start position:0% +without the +inverse I'll still I'll use so so P + + align:start position:0% +inverse I'll still I'll use so so P + + + align:start position:0% +inverse I'll still I'll use so so P +inverse is our a transpose Sigma inverse + + align:start position:0% +inverse is our a transpose Sigma inverse + + + align:start position:0% +inverse is our a transpose Sigma inverse +a just you can I poke this up here some + + align:start position:0% +a just you can I poke this up here some + + + align:start position:0% +a just you can I poke this up here some +just as a reminder P inverse is a + + align:start position:0% +just as a reminder P inverse is a + + + align:start position:0% +just as a reminder P inverse is a +transpose Sigma inverse a it's it's what + + align:start position:0% +transpose Sigma inverse a it's it's what + + + align:start position:0% +transpose Sigma inverse a it's it's what +we just figured out actually so I I've + + align:start position:0% +we just figured out actually so I I've + + + align:start position:0% +we just figured out actually so I I've +I've really this this + + align:start position:0% +I've really this this + + + align:start position:0% +I've really this this +says this says P + + align:start position:0% +says this says P + + + align:start position:0% +says this says P +inverse this this this formula that we + + align:start position:0% +inverse this this this formula that we + + + align:start position:0% +inverse this this this formula that we +just got says P inverse new that's what + + align:start position:0% +just got says P inverse new that's what + + + align:start position:0% +just got says P inverse new that's what +we were Computing is now what is this + + align:start position:0% +we were Computing is now what is this + + + align:start position:0% +we were Computing is now what is this +what is that quantity + + align:start position:0% +what is that quantity + + + align:start position:0% +what is that quantity +there that's P inverse + + align:start position:0% +there that's P inverse + + + align:start position:0% +there that's P inverse +old so P inverse no I shouldn't say new + + align:start position:0% +old so P inverse no I shouldn't say new + + + align:start position:0% +old so P inverse no I shouldn't say new +I should + + align:start position:0% +I should + + + align:start position:0% +I should +say uh combined or something P inverse + + align:start position:0% +say uh combined or something P inverse + + + align:start position:0% +say uh combined or something P inverse +combined or P1 inverse yeah I I'd be a + + align:start position:0% +combined or P1 inverse yeah I I'd be a + + + align:start position:0% +combined or P1 inverse yeah I I'd be a +lot better if I just use zero and one + + align:start position:0% +lot better if I just use zero and one + + + align:start position:0% +lot better if I just use zero and one +for zero for old one for new I guess + + align:start position:0% +for zero for old one for new I guess + + + align:start position:0% +for zero for old one for new I guess +there's a value to having numbers in + + align:start position:0% +there's a value to having numbers in + + + align:start position:0% +there's a value to having numbers in +this uh World okay so + + align:start position:0% +this uh World okay so + + + align:start position:0% +this uh World okay so +P1 inverse the the combined the the the + + align:start position:0% +P1 inverse the the combined the the the + + + align:start position:0% +P1 inverse the the combined the the the +the one + + align:start position:0% +the one + + + align:start position:0% +the one +that right is according to this formula + + align:start position:0% +that right is according to this formula + + + align:start position:0% +that right is according to this formula +is p the old + + align:start position:0% +is p the old + + + align:start position:0% +is p the old +one inverse because that's P inverse + + align:start position:0% +one inverse because that's P inverse + + + align:start position:0% +one inverse because that's P inverse +plus this correction that's the + + align:start position:0% +plus this correction that's the + + + align:start position:0% +plus this correction that's the +a new inverse a new if we're calling one + + align:start position:0% +a new inverse a new if we're calling one + + + align:start position:0% +a new inverse a new if we're calling one +for that transpose Sigma inverse 1 A1 + + align:start position:0% +for that transpose Sigma inverse 1 A1 + + + align:start position:0% +for that transpose Sigma inverse 1 A1 +that's the update formula + + align:start position:0% + + + + align:start position:0% + +so that's the update formula for this + + align:start position:0% +so that's the update formula for this + + + align:start position:0% +so that's the update formula for this +crucial quantity P or in fact for p + + align:start position:0% +crucial quantity P or in fact for p + + + align:start position:0% +crucial quantity P or in fact for p +inverse what we just found so you see + + align:start position:0% +inverse what we just found so you see + + + align:start position:0% +inverse what we just found so you see +that actually as we + + align:start position:0% +that actually as we + + + align:start position:0% +that actually as we +proceed it often happens that we figure + + align:start position:0% +proceed it often happens that we figure + + + align:start position:0% +proceed it often happens that we figure +out the update in the P because that's + + align:start position:0% +out the update in the P because that's + + + align:start position:0% +out the update in the P because that's +because P inverse is the Matrix here + + align:start position:0% +because P inverse is the Matrix here + + + align:start position:0% +because P inverse is the Matrix here +that that leads us to U it's remember + + align:start position:0% +that that leads us to U it's remember + + + align:start position:0% +that that leads us to U it's remember +you hat got this + + align:start position:0% +you hat got this + + + align:start position:0% +you hat got this +this is all this stuff here is + + align:start position:0% +this is all this stuff here is + + + align:start position:0% +this is all this stuff here is +p in there so if it's no surprise that + + align:start position:0% +p in there so if it's no surprise that + + + align:start position:0% +p in there so if it's no surprise that +updating p is a is an important step + + align:start position:0% +updating p is a is an important step + + + align:start position:0% +updating p is a is an important step +toward the update of U and an important + + align:start position:0% +toward the update of U and an important + + + align:start position:0% +toward the update of U and an important +step on its own okay now I'm ready for + + align:start position:0% +step on its own okay now I'm ready for + + + align:start position:0% +step on its own okay now I'm ready for +the update in U okay so what is + + align:start position:0% + + + + align:start position:0% + +U so + + align:start position:0% +U so + + + align:start position:0% +U so +you combined you one the the the answer + + align:start position:0% +you combined you one the the the answer + + + align:start position:0% +you combined you one the the the answer +with for the combined problem is okay + + align:start position:0% +with for the combined problem is okay + + + align:start position:0% +with for the combined problem is okay +well let's see what it was here it's + + align:start position:0% +well let's see what it was here it's + + + align:start position:0% +well let's see what it was here it's +P1 that's all this stuff times a what a + + align:start position:0% +P1 that's all this stuff times a what a + + + align:start position:0% +P1 that's all this stuff times a what a +is that that's both A's isn't it yeah + + align:start position:0% +is that that's both A's isn't it yeah + + + align:start position:0% +is that that's both A's isn't it yeah +that's the combined a and the + + align:start position:0% + + + + align:start position:0% + +combined right see have we got it + + align:start position:0% +combined right see have we got it + + + align:start position:0% +combined right see have we got it +this is now I'm looking for yeah what + + align:start position:0% +this is now I'm looking for yeah what + + + align:start position:0% +this is now I'm looking for yeah what +what's in + + align:start position:0% +what's in + + + align:start position:0% +what's in +here + + align:start position:0% + + + + align:start position:0% + +okay is this + + align:start position:0% +okay is this + + + align:start position:0% +okay is this +part which is if I write b as B KN B1 + + align:start position:0% +part which is if I write b as B KN B1 + + + align:start position:0% +part which is if I write b as B KN B1 +and I write Sigma inverse as Sigma not + + align:start position:0% +and I write Sigma inverse as Sigma not + + + align:start position:0% +and I write Sigma inverse as Sigma not +inverse Sigma 1 inverse and I write a as + + align:start position:0% +inverse Sigma 1 inverse and I write a as + + + align:start position:0% +inverse Sigma 1 inverse and I write a as +a A1 I've got two pieces I've got a + + align:start position:0% +a A1 I've got two pieces I've got a + + + align:start position:0% +a A1 I've got two pieces I've got a +not + + align:start position:0% +not + + + align:start position:0% +not +transpose P not + + align:start position:0% +transpose P not + + + align:start position:0% +transpose P not +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +inverse oh no + + align:start position:0% +inverse oh no + + + align:start position:0% +inverse oh no +Sigma yep Sigma n + + align:start position:0% +Sigma yep Sigma n + + + align:start position:0% +Sigma yep Sigma n +inverse B not that's the old part + + align:start position:0% +inverse B not that's the old part + + + align:start position:0% +inverse B not that's the old part +plus + + align:start position:0% +plus + + + align:start position:0% +plus +a + + align:start position:0% +a + + + align:start position:0% +a +new transpose Sigma inverse B1 the new + + align:start position:0% +new transpose Sigma inverse B1 the new + + + align:start position:0% +new transpose Sigma inverse B1 the new +stuff + + align:start position:0% +stuff + + + align:start position:0% +stuff +okay that's our exact formula that's + + align:start position:0% +okay that's our exact formula that's + + + align:start position:0% +okay that's our exact formula that's +that's we haven't simplified it + + align:start position:0% +that's we haven't simplified it + + + align:start position:0% +that's we haven't simplified it +all this is what we would have to + + align:start position:0% + + + + align:start position:0% + +do if we don't use recursion this is the + + align:start position:0% +do if we don't use recursion this is the + + + align:start position:0% +do if we don't use recursion this is the +this is the answer if we just tackle the + + align:start position:0% +this is the answer if we just tackle the + + + align:start position:0% +this is the answer if we just tackle the +the new problem the the combined problem + + align:start position:0% +the new problem the the combined problem + + + align:start position:0% +the new problem the the combined problem +without paying any attention to the work + + align:start position:0% +without paying any attention to the work + + + align:start position:0% +without paying any attention to the work +we did before but now we want to use + + align:start position:0% +we did before but now we want to use + + + align:start position:0% +we did before but now we want to use +that work we did did before so what did + + align:start position:0% +that work we did did before so what did + + + align:start position:0% +that work we did did before so what did +we achieve + + align:start position:0% + + + + align:start position:0% + +before we we figured out P not inverse + + align:start position:0% +before we we figured out P not inverse + + + align:start position:0% +before we we figured out P not inverse +before and we have an update formula for + + align:start position:0% +before and we have an update formula for + + + align:start position:0% +before and we have an update formula for +P1 + + align:start position:0% +P1 + + + align:start position:0% +P1 +inverse okay and we can so I'm going to + + align:start position:0% +inverse okay and we can so I'm going to + + + align:start position:0% +inverse okay and we can so I'm going to +this this update is going to get plugged + + align:start position:0% +this this update is going to get plugged + + + align:start position:0% +this this update is going to get plugged +into here okay why don't + + align:start position:0% +into here okay why don't + + + align:start position:0% +into here okay why don't +I go to the answer I think that's + + align:start position:0% +I go to the answer I think that's + + + align:start position:0% +I go to the answer I think that's +reasonable because the the it's just two + + align:start position:0% +reasonable because the the it's just two + + + align:start position:0% +reasonable because the the it's just two +or three steps + + align:start position:0% +or three steps + + + align:start position:0% +or three steps +that lead to this final answer and I + + align:start position:0% +that lead to this final answer and I + + + align:start position:0% +that lead to this final answer and I +think the The crucial thing is to say + + align:start position:0% +think the The crucial thing is to say + + + align:start position:0% +think the The crucial thing is to say +what is K and that let's complete the + + align:start position:0% +what is K and that let's complete the + + + align:start position:0% +what is K and that let's complete the +lecture with that so I I if that's all + + align:start position:0% +lecture with that so I I if that's all + + + align:start position:0% +lecture with that so I I if that's all +right with you if I just proceed + + align:start position:0% +right with you if I just proceed + + + align:start position:0% +right with you if I just proceed +systematically as the as the uh + + align:start position:0% +systematically as the as the uh + + + align:start position:0% +systematically as the as the uh +Exposition does this is + + align:start position:0% +Exposition does this is + + + align:start position:0% +Exposition does this is +Page um + + align:start position:0% +Page um + + + align:start position:0% +Page um +146 that I'm + + align:start position:0% +146 that I'm + + + align:start position:0% +146 that I'm +using and let me just write down what + + align:start position:0% +using and let me just write down what + + + align:start position:0% +using and let me just write down what +this cman Matrix turns out to be because + + align:start position:0% +this cman Matrix turns out to be because + + + align:start position:0% +this cman Matrix turns out to be because +that's the The crucial quantity it's + + align:start position:0% +that's the The crucial quantity it's + + + align:start position:0% +that's the The crucial quantity it's +P1 the updated + + align:start position:0% +P1 the updated + + + align:start position:0% +P1 the updated +P A1 + + align:start position:0% +P A1 + + + align:start position:0% +P A1 +transpose Sigma + + align:start position:0% +transpose Sigma + + + align:start position:0% +transpose Sigma +1 the new the the new bit of the new bit + + align:start position:0% +1 the new the the new bit of the new bit + + + align:start position:0% +1 the new the the new bit of the new bit +of a the new bit of Sigma and the then + + align:start position:0% +of a the new bit of Sigma and the then + + + align:start position:0% +of a the new bit of Sigma and the then +the combined and the updated Peak that's + + align:start position:0% +the combined and the updated Peak that's + + + align:start position:0% +the combined and the updated Peak that's +the cman game Matrix + + align:start position:0% +the cman game Matrix + + + align:start position:0% +the cman game Matrix +and that's what makes this formula + + align:start position:0% +and that's what makes this formula + + + align:start position:0% +and that's what makes this formula +correct and it's it's + + align:start position:0% +correct and it's it's + + + align:start position:0% +correct and it's it's +uh I feel I've covered the board and + + align:start position:0% +uh I feel I've covered the board and + + + align:start position:0% +uh I feel I've covered the board and +asked you to watch uh a bunch of Matrix + + align:start position:0% +asked you to watch uh a bunch of Matrix + + + align:start position:0% +asked you to watch uh a bunch of Matrix +steps on the other hand what worries me + + align:start position:0% +steps on the other hand what worries me + + + align:start position:0% +steps on the other hand what worries me +is this was nothing compared to + + align:start position:0% +is this was nothing compared to + + + align:start position:0% +is this was nothing compared to +kman cuz we only + + align:start position:0% +kman cuz we only + + + align:start position:0% +kman cuz we only +updated uh we only we only had new B's + + align:start position:0% +updated uh we only we only had new B's + + + align:start position:0% +updated uh we only we only had new B's +and new row in you but not a new not new + + align:start position:0% +and new row in you but not a new not new + + + align:start position:0% +and new row in you but not a new not new +column + + align:start position:0% +column + + + align:start position:0% +column +so the next lecture can only get + + align:start position:0% +so the next lecture can only get + + + align:start position:0% +so the next lecture can only get +worse uh uh but I'll probably have I'll + + align:start position:0% +worse uh uh but I'll probably have I'll + + + align:start position:0% +worse uh uh but I'll probably have I'll +probably shortcut it by again + + align:start position:0% +probably shortcut it by again + + + align:start position:0% +probably shortcut it by again +emphasizing that this this is the thing + + align:start position:0% +emphasizing that this this is the thing + + + align:start position:0% +emphasizing that this this is the thing +to like remember what are the inputs + + align:start position:0% +to like remember what are the inputs + + + align:start position:0% +to like remember what are the inputs +what are the outputs the + + align:start position:0% +what are the outputs the + + + align:start position:0% +what are the outputs the +formulas clearly it's not essential to + + align:start position:0% +formulas clearly it's not essential to + + + align:start position:0% +formulas clearly it's not essential to +couldn't try to memorize or even + + align:start position:0% +couldn't try to memorize or even + + + align:start position:0% +couldn't try to memorize or even +reproduce all of them but what are the + + align:start position:0% +reproduce all of them but what are the + + + align:start position:0% +reproduce all of them but what are the +inputs what are the outputs and then + + align:start position:0% +inputs what are the outputs and then + + + align:start position:0% +inputs what are the outputs and then +what's the + + align:start position:0% +what's the + + + align:start position:0% +what's the +problem what's the goal and here was the + + align:start position:0% +problem what's the goal and here was the + + + align:start position:0% +problem what's the goal and here was the +problem of this lecture which I'm going + + align:start position:0% +problem of this lecture which I'm going + + + align:start position:0% +problem of this lecture which I'm going +to call it quits now and then the second + + align:start position:0% +to call it quits now and then the second + + + align:start position:0% +to call it quits now and then the second +lecture uh should we well let's say + + align:start position:0% +lecture uh should we well let's say + + + align:start position:0% +lecture uh should we well let's say +start at + + align:start position:0% +start at + + + align:start position:0% +start at +3:30 okay 3:30 for the second lecture + + align:start position:0% +3:30 okay 3:30 for the second lecture + + + align:start position:0% +3:30 okay 3:30 for the second lecture +I've learned that uh a guy name guy + + align:start position:0% +I've learned that uh a guy name guy + + + align:start position:0% +I've learned that uh a guy name guy +named Eric Missour from Harvard who's a + + align:start position:0% +named Eric Missour from Harvard who's a + + + align:start position:0% +named Eric Missour from Harvard who's a +who's uh maybe the outstanding person in + + align:start position:0% +who's uh maybe the outstanding person in + + + align:start position:0% +who's uh maybe the outstanding person in +Science Education these these days is + + align:start position:0% +Science Education these these days is + + + align:start position:0% +Science Education these these days is +speaking just right now in the + + align:start position:0% +speaking just right now in the + + + align:start position:0% +speaking just right now in the +auditorium is it yeah so I'm going to at + + align:start position:0% +auditorium is it yeah so I'm going to at + + + align:start position:0% +auditorium is it yeah so I'm going to at +least go and see what he's looks like um + + align:start position:0% +least go and see what he's looks like um + + + align:start position:0% +least go and see what he's looks like um +and um be ready for 3:30 cman filter and + + align:start position:0% +and um be ready for 3:30 cman filter and + + + align:start position:0% +and um be ready for 3:30 cman filter and +ready for advice from you uh offline in + + align:start position:0% +ready for advice from you uh offline in + + + align:start position:0% +ready for advice from you uh offline in +person or uh by email in between okay + + align:start position:0% +person or uh by email in between okay + + + align:start position:0% +person or uh by email in between okay +see you at + + align:start position:0% +see you at + + + align:start position:0% +see you at +3:30 what was that + + align:start position:0% +3:30 what was that + + + align:start position:0% +3:30 what was that +page uh the book you have that that book + + align:start position:0% +page uh the book you have that that book + + + align:start position:0% +page uh the book you have that that book +right yeah that's right page 14 right + + align:start position:0% +right yeah that's right page 14 right + + + align:start position:0% +right yeah that's right page 14 right +right and then \ No newline at end of file diff --git a/Rvnv3bPDCs8.txt b/Rvnv3bPDCs8.txt new file mode 100644 index 0000000000000000000000000000000000000000..1a1666a455e7f97dbc7a3ea115cfa0de1402f4ec --- /dev/null +++ b/Rvnv3bPDCs8.txt @@ -0,0 +1,5467 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT open courseware continue + + align:start position:0% +will help MIT open courseware continue + + + align:start position:0% +will help MIT open courseware continue +to offer highquality educational + + align:start position:0% +to offer highquality educational + + + align:start position:0% +to offer highquality educational +resources for free to make a donation or + + align:start position:0% +resources for free to make a donation or + + + align:start position:0% +resources for free to make a donation or +view additional materials from hundreds + + align:start position:0% +view additional materials from hundreds + + + align:start position:0% +view additional materials from hundreds +of MIT courses visit MIT opencourseware + + align:start position:0% +of MIT courses visit MIT opencourseware + + + align:start position:0% +of MIT courses visit MIT opencourseware +at ocw.mit.edu + + align:start position:0% + + + + align:start position:0% + +hi our main aim today is to successfully + + align:start position:0% +hi our main aim today is to successfully + + + align:start position:0% +hi our main aim today is to successfully +conclude block three and to set the + + align:start position:0% +conclude block three and to set the + + + align:start position:0% +conclude block three and to set the +stage for introducing block four Now by + + align:start position:0% +stage for introducing block four Now by + + + align:start position:0% +stage for introducing block four Now by +way of Brief Review we may have become + + align:start position:0% +way of Brief Review we may have become + + + align:start position:0% +way of Brief Review we may have become +so involved with our discussion of the + + align:start position:0% +so involved with our discussion of the + + + align:start position:0% +so involved with our discussion of the +last few lessons where we've done the + + align:start position:0% +last few lessons where we've done the + + + align:start position:0% +last few lessons where we've done the +chain rule that we may have forgotten + + align:start position:0% +chain rule that we may have forgotten + + + align:start position:0% +chain rule that we may have forgotten +that the basic ingredient that we had + + align:start position:0% +that the basic ingredient that we had + + + align:start position:0% +that the basic ingredient that we had +arrived at that set up our proof of the + + align:start position:0% +arrived at that set up our proof of the + + + align:start position:0% +arrived at that set up our proof of the +chain Rule and then after that we get + + align:start position:0% +chain Rule and then after that we get + + + align:start position:0% +chain Rule and then after that we get +involved in the computation of how to + + align:start position:0% +involved in the computation of how to + + + align:start position:0% +involved in the computation of how to +use the chain rule but the basic + + align:start position:0% +use the chain rule but the basic + + + align:start position:0% +use the chain rule but the basic +ingredient was the idea that we had + + align:start position:0% +ingredient was the idea that we had + + + align:start position:0% +ingredient was the idea that we had +obtained a linear approximation a Delta + + align:start position:0% +obtained a linear approximation a Delta + + + align:start position:0% +obtained a linear approximation a Delta +W tan idea and this concept leads to the + + align:start position:0% +W tan idea and this concept leads to the + + + align:start position:0% +W tan idea and this concept leads to the +idea of a differential which is an + + align:start position:0% +idea of a differential which is an + + + align:start position:0% +idea of a differential which is an +extension of the idea of differentials + + align:start position:0% +extension of the idea of differentials + + + align:start position:0% +extension of the idea of differentials +as we knew them in part one of our + + align:start position:0% +as we knew them in part one of our + + + align:start position:0% +as we knew them in part one of our +course and what I would like to do is to + + align:start position:0% +course and what I would like to do is to + + + align:start position:0% +course and what I would like to do is to +talk somewhat briefly about this topic + + align:start position:0% +talk somewhat briefly about this topic + + + align:start position:0% +talk somewhat briefly about this topic +to show how it introduces what will be + + align:start position:0% +to show how it introduces what will be + + + align:start position:0% +to show how it introduces what will be +the main body of material in Block four + + align:start position:0% +the main body of material in Block four + + + align:start position:0% +the main body of material in Block four +and an important application that we can + + align:start position:0% +and an important application that we can + + + align:start position:0% +and an important application that we can +handle now that will show why it's worth + + align:start position:0% +handle now that will show why it's worth + + + align:start position:0% +handle now that will show why it's worth +understanding certain things about + + align:start position:0% +understanding certain things about + + + align:start position:0% +understanding certain things about +differentials even on a very Elementary + + align:start position:0% +differentials even on a very Elementary + + + align:start position:0% +differentials even on a very Elementary +level any rate the topic that I've + + align:start position:0% +level any rate the topic that I've + + + align:start position:0% +level any rate the topic that I've +chosen for today is called exact + + align:start position:0% +chosen for today is called exact + + + align:start position:0% +chosen for today is called exact +differentials and the idea again is + + align:start position:0% +differentials and the idea again is + + + align:start position:0% +differentials and the idea again is +completely analogous to what we did in + + align:start position:0% +completely analogous to what we did in + + + align:start position:0% +completely analogous to what we did in +calculus of a single variable we start + + align:start position:0% +calculus of a single variable we start + + + align:start position:0% +calculus of a single variable we start +with wals f ofx y and we showed that if + + align:start position:0% +with wals f ofx y and we showed that if + + + align:start position:0% +with wals f ofx y and we showed that if +W was a continuously differentiable + + align:start position:0% +W was a continuously differentiable + + + align:start position:0% +W was a continuously differentiable +function of X and Y it made sense to + + align:start position:0% +function of X and Y it made sense to + + + align:start position:0% +function of X and Y it made sense to +emphasize the expression called Delta W + + align:start position:0% +emphasize the expression called Delta W + + + align:start position:0% +emphasize the expression called Delta W +tan which was the partial of effort + + align:start position:0% +tan which was the partial of effort + + + align:start position:0% +tan which was the partial of effort +respect to X evaluated a given point + + align:start position:0% +respect to X evaluated a given point + + + align:start position:0% +respect to X evaluated a given point +time Delta X plus the partial of effort + + align:start position:0% +time Delta X plus the partial of effort + + + align:start position:0% +time Delta X plus the partial of effort +respect to Y at that same point times + + align:start position:0% +respect to Y at that same point times + + + align:start position:0% +respect to Y at that same point times +Delta Y and what we do is the same thing + + align:start position:0% +Delta Y and what we do is the same thing + + + align:start position:0% +Delta Y and what we do is the same thing +that we did as I say in calculus of a + + align:start position:0% +that we did as I say in calculus of a + + + align:start position:0% +that we did as I say in calculus of a +single variable we introduce a new + + align:start position:0% +single variable we introduce a new + + + align:start position:0% +single variable we introduce a new +language we write Delta W tan now as DW + + align:start position:0% +language we write Delta W tan now as DW + + + align:start position:0% +language we write Delta W tan now as DW +we write Delta X as DX Delta y as + + align:start position:0% +we write Delta X as DX Delta y as + + + align:start position:0% +we write Delta X as DX Delta y as +Dy and what we say is that DW is the + + align:start position:0% +Dy and what we say is that DW is the + + + align:start position:0% +Dy and what we say is that DW is the +total differential of w to see how this + + align:start position:0% +total differential of w to see how this + + + align:start position:0% +total differential of w to see how this +is analogous to what happened in + + align:start position:0% +is analogous to what happened in + + + align:start position:0% +is analogous to what happened in +calculus of a single variable notice for + + align:start position:0% +calculus of a single variable notice for + + + align:start position:0% +calculus of a single variable notice for +the sake of argument that if F happens + + align:start position:0% +the sake of argument that if F happens + + + align:start position:0% +the sake of argument that if F happens +to be a function of X alone so that + + align:start position:0% +to be a function of X alone so that + + + align:start position:0% +to be a function of X alone so that +there is no second variable in other + + align:start position:0% +there is no second variable in other + + + align:start position:0% +there is no second variable in other +words if f is independent of Y notice + + align:start position:0% +words if f is independent of Y notice + + + align:start position:0% +words if f is independent of Y notice +that the partial of f respect to Y will + + align:start position:0% +that the partial of f respect to Y will + + + align:start position:0% +that the partial of f respect to Y will +be zero and we will then have that W is + + align:start position:0% +be zero and we will then have that W is + + + align:start position:0% +be zero and we will then have that W is +a function of X alone DW then will be + + align:start position:0% +a function of X alone DW then will be + + + align:start position:0% +a function of X alone DW then will be +what well in that case the partial of f + + align:start position:0% +what well in that case the partial of f + + + align:start position:0% +what well in that case the partial of f +respect to X is the the ordinary + + align:start position:0% +respect to X is the the ordinary + + + align:start position:0% +respect to X is the the ordinary +derivative of f respect to X time DX and + + align:start position:0% +derivative of f respect to X time DX and + + + align:start position:0% +derivative of f respect to X time DX and +we're back to our old recipe that DW is + + align:start position:0% +we're back to our old recipe that DW is + + + align:start position:0% +we're back to our old recipe that DW is +dwdx time DX that this is a natural + + align:start position:0% +dwdx time DX that this is a natural + + + align:start position:0% +dwdx time DX that this is a natural +extension of what happened in calculus + + align:start position:0% +extension of what happened in calculus + + + align:start position:0% +extension of what happened in calculus +of a single variable all right now what + + align:start position:0% +of a single variable all right now what + + + align:start position:0% +of a single variable all right now what +leads into the next block and what and + + align:start position:0% +leads into the next block and what and + + + align:start position:0% +leads into the next block and what and +why we're going to drop this for the + + align:start position:0% +why we're going to drop this for the + + + align:start position:0% +why we're going to drop this for the +time being but to go up to a different + + align:start position:0% +time being but to go up to a different + + + align:start position:0% +time being but to go up to a different +aspect of this is notice that if we can + + align:start position:0% +aspect of this is notice that if we can + + + align:start position:0% +aspect of this is notice that if we can +assume that + + align:start position:0% +assume that + + + align:start position:0% +assume that +DW can replace Delta W if we can assume + + align:start position:0% +DW can replace Delta W if we can assume + + + align:start position:0% +DW can replace Delta W if we can assume +as we as we talked about in the case of + + align:start position:0% +as we as we talked about in the case of + + + align:start position:0% +as we as we talked about in the case of +L differentiable functions that the + + align:start position:0% +L differentiable functions that the + + + align:start position:0% +L differentiable functions that the +difference between Delta W and Delta W + + align:start position:0% +difference between Delta W and Delta W + + + align:start position:0% +difference between Delta W and Delta W +tan is negligible for sufficiently small + + align:start position:0% +tan is negligible for sufficiently small + + + align:start position:0% +tan is negligible for sufficiently small +Delta X and Delta y notice that the + + align:start position:0% +Delta X and Delta y notice that the + + + align:start position:0% +Delta X and Delta y notice that the +equation DW equals F subx DX plus F suby + + align:start position:0% +equation DW equals F subx DX plus F suby + + + align:start position:0% +equation DW equals F subx DX plus F suby +Dy since F subx and F suby are computed + + align:start position:0% +Dy since F subx and F suby are computed + + + align:start position:0% +Dy since F subx and F suby are computed +at a given point these become what + + align:start position:0% +at a given point these become what + + + align:start position:0% +at a given point these become what +linear combinations of DX and Dy a + + align:start position:0% +linear combinations of DX and Dy a + + + align:start position:0% +linear combinations of DX and Dy a +constant time DX plus a constant time Dy + + align:start position:0% +constant time DX plus a constant time Dy + + + align:start position:0% +constant time DX plus a constant time Dy +and we're into the subject of linear + + align:start position:0% +and we're into the subject of linear + + + align:start position:0% +and we're into the subject of linear +equations which we will talk about next + + align:start position:0% +equations which we will talk about next + + + align:start position:0% +equations which we will talk about next +time for the the time being all I want + + align:start position:0% +time for the the time being all I want + + + align:start position:0% +time for the the time being all I want +to point out is that DW is called the + + align:start position:0% +to point out is that DW is called the + + + align:start position:0% +to point out is that DW is called the +total differential of w and that + + align:start position:0% +total differential of w and that + + + align:start position:0% +total differential of w and that +conversely starting with any expression + + align:start position:0% +conversely starting with any expression + + + align:start position:0% +conversely starting with any expression +of the form some function M of X and Y * + + align:start position:0% +of the form some function M of X and Y * + + + align:start position:0% +of the form some function M of X and Y * +DX plus some function n of X and Y * Dy + + align:start position:0% +DX plus some function n of X and Y * Dy + + + align:start position:0% +DX plus some function n of X and Y * Dy +in other words M of XY DX plus n of XY + + align:start position:0% +in other words M of XY DX plus n of XY + + + align:start position:0% +in other words M of XY DX plus n of XY +Dy no matter what functions of X and Y M + + align:start position:0% +Dy no matter what functions of X and Y M + + + align:start position:0% +Dy no matter what functions of X and Y M +and N are any expression of this form is + + align:start position:0% +and N are any expression of this form is + + + align:start position:0% +and N are any expression of this form is +called a differential by the way you may + + align:start position:0% +called a differential by the way you may + + + align:start position:0% +called a differential by the way you may +recall that you were used to calling DX + + align:start position:0% +recall that you were used to calling DX + + + align:start position:0% +recall that you were used to calling DX +a differential backend calculus of a + + align:start position:0% +a differential backend calculus of a + + + align:start position:0% +a differential backend calculus of a +single variable notice that in + + align:start position:0% +single variable notice that in + + + align:start position:0% +single variable notice that in +particular one choice of capital N is to + + align:start position:0% +particular one choice of capital N is to + + + align:start position:0% +particular one choice of capital N is to +have n of X Y be identically zero we + + align:start position:0% +have n of X Y be identically zero we + + + align:start position:0% +have n of X Y be identically zero we +could have M of XY be identically one in + + align:start position:0% +could have M of XY be identically one in + + + align:start position:0% +could have M of XY be identically one in +which case MDX plus ndy would simply be + + align:start position:0% +which case MDX plus ndy would simply be + + + align:start position:0% +which case MDX plus ndy would simply be +1 DX + 0 Dy or DX in other words notice + + align:start position:0% +1 DX + 0 Dy or DX in other words notice + + + align:start position:0% +1 DX + 0 Dy or DX in other words notice +that this extended definition of a + + align:start position:0% +that this extended definition of a + + + align:start position:0% +that this extended definition of a +differential for two or more variables + + align:start position:0% +differential for two or more variables + + + align:start position:0% +differential for two or more variables +includes the definition for a single + + align:start position:0% +includes the definition for a single + + + align:start position:0% +includes the definition for a single +variable at any rate any expression of + + align:start position:0% +variable at any rate any expression of + + + align:start position:0% +variable at any rate any expression of +this type is called a differential and + + align:start position:0% +this type is called a differential and + + + align:start position:0% +this type is called a differential and +again a very natural question that comes + + align:start position:0% +again a very natural question that comes + + + align:start position:0% +again a very natural question that comes +up is who wants differentials why do we + + align:start position:0% +up is who wants differentials why do we + + + align:start position:0% +up is who wants differentials why do we +need them and perhaps the best + + align:start position:0% +need them and perhaps the best + + + align:start position:0% +need them and perhaps the best +application comes from the clue that a + + align:start position:0% +application comes from the clue that a + + + align:start position:0% +application comes from the clue that a +certain subject is called differential + + align:start position:0% +certain subject is called differential + + + align:start position:0% +certain subject is called differential +equations rather than derivative + + align:start position:0% +equations rather than derivative + + + align:start position:0% +equations rather than derivative +equations let me illustrate this in + + align:start position:0% +equations let me illustrate this in + + + align:start position:0% +equations let me illustrate this in +terms of a what I think is a rather nice + + align:start position:0% +terms of a what I think is a rather nice + + + align:start position:0% +terms of a what I think is a rather nice +example in the sense that it would be + + align:start position:0% +example in the sense that it would be + + + align:start position:0% +example in the sense that it would be +hard to guess the answer but rather easy + + align:start position:0% +hard to guess the answer but rather easy + + + align:start position:0% +hard to guess the answer but rather easy +to visualize what the problem says at + + align:start position:0% +to visualize what the problem says at + + + align:start position:0% +to visualize what the problem says at +least let's imagine I have a certain + + align:start position:0% +least let's imagine I have a certain + + + align:start position:0% +least let's imagine I have a certain +curve s in the XY plane I don't tell you + + align:start position:0% +curve s in the XY plane I don't tell you + + + align:start position:0% +curve s in the XY plane I don't tell you +anything else about that curve except + + align:start position:0% +anything else about that curve except + + + align:start position:0% +anything else about that curve except +that its slope at any point x comma Y is + + align:start position:0% +that its slope at any point x comma Y is + + + align:start position:0% +that its slope at any point x comma Y is +given by the very interesting + + align:start position:0% +given by the very interesting + + + align:start position:0% +given by the very interesting +relationship that it's the quotient of + + align:start position:0% +relationship that it's the quotient of + + + align:start position:0% +relationship that it's the quotient of +the square of its distance from the + + align:start position:0% +the square of its distance from the + + + align:start position:0% +the square of its distance from the +origin over twice the product of its + + align:start position:0% +origin over twice the product of its + + + align:start position:0% +origin over twice the product of its +coordinates in other words to find the + + align:start position:0% +coordinates in other words to find the + + + align:start position:0% +coordinates in other words to find the +slope of the curve S at the point x + + align:start position:0% +slope of the curve S at the point x + + + align:start position:0% +slope of the curve S at the point x +comma y i Square the + + align:start position:0% +comma y i Square the + + + align:start position:0% +comma y i Square the +distance of the point from the + + align:start position:0% +distance of the point from the + + + align:start position:0% +distance of the point from the +origin take the negative of that divide + + align:start position:0% +origin take the negative of that divide + + + align:start position:0% +origin take the negative of that divide +by twice the product of the coordinates + + align:start position:0% +by twice the product of the coordinates + + + align:start position:0% +by twice the product of the coordinates +and that's going to be the slope now + + align:start position:0% +and that's going to be the slope now + + + align:start position:0% +and that's going to be the slope now +certainly that makes sense geometrically + + align:start position:0% +certainly that makes sense geometrically + + + align:start position:0% +certainly that makes sense geometrically +but what type of a curve would have that + + align:start position:0% +but what type of a curve would have that + + + align:start position:0% +but what type of a curve would have that +property and even assuming that we knew + + align:start position:0% +property and even assuming that we knew + + + align:start position:0% +property and even assuming that we knew +such a curve how in the world can you + + align:start position:0% +such a curve how in the world can you + + + align:start position:0% +such a curve how in the world can you +express it in a convenient manner well + + align:start position:0% +express it in a convenient manner well + + + align:start position:0% +express it in a convenient manner well +here's the idea again back to the same + + align:start position:0% +here's the idea again back to the same + + + align:start position:0% +here's the idea again back to the same +technique that we use in calculus of a + + align:start position:0% +technique that we use in calculus of a + + + align:start position:0% +technique that we use in calculus of a +single variable algebraically this is + + align:start position:0% +single variable algebraically this is + + + align:start position:0% +single variable algebraically this is +our equation if we cross multiply and + + align:start position:0% +our equation if we cross multiply and + + + align:start position:0% +our equation if we cross multiply and +collect all our terms onto one side of + + align:start position:0% +collect all our terms onto one side of + + + align:start position:0% +collect all our terms onto one side of +the equation we obtain what we call the + + align:start position:0% +the equation we obtain what we call the + + + align:start position:0% +the equation we obtain what we call the +differential equation see it's an + + align:start position:0% +differential equation see it's an + + + align:start position:0% +differential equation see it's an +equation involving a differential in + + align:start position:0% +equation involving a differential in + + + align:start position:0% +equation involving a differential in +fact in this case using our general + + align:start position:0% +fact in this case using our general + + + align:start position:0% +fact in this case using our general +notation M of X Y is x^2 + y^2 and N of + + align:start position:0% +notation M of X Y is x^2 + y^2 and N of + + + align:start position:0% +notation M of X Y is x^2 + y^2 and N of +X Y is 2x y we have a differential equal + + align:start position:0% +X Y is 2x y we have a differential equal + + + align:start position:0% +X Y is 2x y we have a differential equal +to zero now without going into this + + align:start position:0% +to zero now without going into this + + + align:start position:0% +to zero now without going into this +right now suppose I just happen to have + + align:start position:0% +right now suppose I just happen to have + + + align:start position:0% +right now suppose I just happen to have +a very quick eye well in fact before I + + align:start position:0% +a very quick eye well in fact before I + + + align:start position:0% +a very quick eye well in fact before I +even say that let me point this out + + align:start position:0% +even say that let me point this out + + + align:start position:0% +even say that let me point this out +we've had problems like this in part one + + align:start position:0% +we've had problems like this in part one + + + align:start position:0% +we've had problems like this in part one +of our course the main difference was is + + align:start position:0% +of our course the main difference was is + + + align:start position:0% +of our course the main difference was is +that we could separate out the variables + + align:start position:0% +that we could separate out the variables + + + align:start position:0% +that we could separate out the variables +we could get the x's and the Y's + + align:start position:0% +we could get the x's and the Y's + + + align:start position:0% +we could get the x's and the Y's +separated remember now Y is implicitly a + + align:start position:0% +separated remember now Y is implicitly a + + + align:start position:0% +separated remember now Y is implicitly a +function of X here in this expression + + align:start position:0% +function of X here in this expression + + + align:start position:0% +function of X here in this expression +because of the equation see X and Y are + + align:start position:0% +because of the equation see X and Y are + + + align:start position:0% +because of the equation see X and Y are +no longer independent when we equate + + align:start position:0% +no longer independent when we equate + + + align:start position:0% +no longer independent when we equate +this to zero the question is though we + + align:start position:0% +this to zero the question is though we + + + align:start position:0% +this to zero the question is though we +cannot solve or separate the x's and the + + align:start position:0% +cannot solve or separate the x's and the + + + align:start position:0% +cannot solve or separate the x's and the +Y's here but if we were lucky that's + + align:start position:0% +Y's here but if we were lucky that's + + + align:start position:0% +Y's here but if we were lucky that's +where luck comes in we would recognize + + align:start position:0% +where luck comes in we would recognize + + + align:start position:0% +where luck comes in we would recognize +that treating y as a function of X the + + align:start position:0% +that treating y as a function of X the + + + align:start position:0% +that treating y as a function of X the +differential on the left hand side is + + align:start position:0% +differential on the left hand side is + + + align:start position:0% +differential on the left hand side is +precisely the differential of 1/3 x Cub + + align:start position:0% +precisely the differential of 1/3 x Cub + + + align:start position:0% +precisely the differential of 1/3 x Cub +Plus x^2 Y in other words the partial of + + align:start position:0% +Plus x^2 Y in other words the partial of + + + align:start position:0% +Plus x^2 Y in other words the partial of +this with respect to X is simply + + align:start position:0% +this with respect to X is simply + + + align:start position:0% +this with respect to X is simply +X2 + + align:start position:0% +X2 + + + align:start position:0% +X2 +uh do I have I think I may have this + + align:start position:0% +uh do I have I think I may have this + + + align:start position:0% +uh do I have I think I may have this +thing in Reverse let me make sure if I + + align:start position:0% +thing in Reverse let me make sure if I + + + align:start position:0% +thing in Reverse let me make sure if I +take the partial of this with respect to + + align:start position:0% +take the partial of this with respect to + + + align:start position:0% +take the partial of this with respect to +X I have 1/3 x cubed plus 2X y right and + + align:start position:0% +X I have 1/3 x cubed plus 2X y right and + + + align:start position:0% +X I have 1/3 x cubed plus 2X y right and +if I take the partial with respect to Y + + align:start position:0% +if I take the partial with respect to Y + + + align:start position:0% +if I take the partial with respect to Y +I simply have X2 at any rate what I'm + + align:start position:0% +I simply have X2 at any rate what I'm + + + align:start position:0% +I simply have X2 at any rate what I'm +saying is if we knew a function who's + + align:start position:0% +saying is if we knew a function who's + + + align:start position:0% +saying is if we knew a function who's +say I have this in Reverse that's what's + + align:start position:0% +say I have this in Reverse that's what's + + + align:start position:0% +say I have this in Reverse that's what's +bothering me here I think the square + + align:start position:0% +bothering me here I think the square + + + align:start position:0% +bothering me here I think the square +should go this way that's not important + + align:start position:0% +should go this way that's not important + + + align:start position:0% +should go this way that's not important +all I'm saying is if I've done this + + align:start position:0% +all I'm saying is if I've done this + + + align:start position:0% +all I'm saying is if I've done this +thing correctly if you take the partial + + align:start position:0% +thing correctly if you take the partial + + + align:start position:0% +thing correctly if you take the partial +of this with respect to Y with respect + + align:start position:0% +of this with respect to Y with respect + + + align:start position:0% +of this with respect to Y with respect +to X you should get this if you take the + + align:start position:0% +to X you should get this if you take the + + + align:start position:0% +to X you should get this if you take the +partial of this with respect to Y you + + align:start position:0% +partial of this with respect to Y you + + + align:start position:0% +partial of this with respect to Y you +should get this and that comes out + + align:start position:0% +should get this and that comes out + + + align:start position:0% +should get this and that comes out +correctly now in other words the partial + + align:start position:0% +correctly now in other words the partial + + + align:start position:0% +correctly now in other words the partial +of this with respect to X is x^2 + y^2 + + align:start position:0% +of this with respect to X is x^2 + y^2 + + + align:start position:0% +of this with respect to X is x^2 + y^2 +the partial of this with respect to Y + + align:start position:0% +the partial of this with respect to Y + + + align:start position:0% +the partial of this with respect to Y +this term drops out and it's just 2x y + + align:start position:0% +this term drops out and it's just 2x y + + + align:start position:0% +this term drops out and it's just 2x y +I'm sorry for that little mistake but I + + align:start position:0% +I'm sorry for that little mistake but I + + + align:start position:0% +I'm sorry for that little mistake but I +won't really apologize for it in the + + align:start position:0% +won't really apologize for it in the + + + align:start position:0% +won't really apologize for it in the +sense that once we found it or even if + + align:start position:0% +sense that once we found it or even if + + + align:start position:0% +sense that once we found it or even if +we didn't find it the key theory is the + + align:start position:0% +we didn't find it the key theory is the + + + align:start position:0% +we didn't find it the key theory is the +same the point is that if we knew a + + align:start position:0% +same the point is that if we knew a + + + align:start position:0% +same the point is that if we knew a +function whose differential was this + + align:start position:0% +function whose differential was this + + + align:start position:0% +function whose differential was this +then the fact that this differential is + + align:start position:0% +then the fact that this differential is + + + align:start position:0% +then the fact that this differential is +zero means the expression itself must be + + align:start position:0% +zero means the expression itself must be + + + align:start position:0% +zero means the expression itself must be +a constant in other words 1/3 x cubed + + + align:start position:0% +a constant in other words 1/3 x cubed + + + + align:start position:0% +a constant in other words 1/3 x cubed + +x y^ 2 must be a + + align:start position:0% +x y^ 2 must be a + + + align:start position:0% +x y^ 2 must be a +constant and therefore what we're saying + + align:start position:0% +constant and therefore what we're saying + + + align:start position:0% +constant and therefore what we're saying +is if we now solve the equation I'm I + + align:start position:0% +is if we now solve the equation I'm I + + + align:start position:0% +is if we now solve the equation I'm I +really am sorry to have botched this for + + align:start position:0% +really am sorry to have botched this for + + + align:start position:0% +really am sorry to have botched this for +you but again as I say the idea + + align:start position:0% +you but again as I say the idea + + + align:start position:0% +you but again as I say the idea +basically comes through unimpeded I now + + align:start position:0% +basically comes through unimpeded I now + + + align:start position:0% +basically comes through unimpeded I now +solve for y in terms of X and I get what + + align:start position:0% +solve for y in terms of X and I get what + + + align:start position:0% +solve for y in terms of X and I get what +that Y is equal to transposing here uh + + align:start position:0% +that Y is equal to transposing here uh + + + align:start position:0% +that Y is equal to transposing here uh +plus or minus the square root of C - 1/3 + + align:start position:0% +plus or minus the square root of C - 1/3 + + + align:start position:0% +plus or minus the square root of C - 1/3 +x Cub all over X in other words the + + align:start position:0% +x Cub all over X in other words the + + + align:start position:0% +x Cub all over X in other words the +family of curves that satisfies this + + align:start position:0% +family of curves that satisfies this + + + align:start position:0% +family of curves that satisfies this +differential equation is precisely this + + align:start position:0% +differential equation is precisely this + + + align:start position:0% +differential equation is precisely this +family here whatever that may look like + + align:start position:0% +family here whatever that may look like + + + align:start position:0% +family here whatever that may look like +in other words this is the family of Cur + + align:start position:0% +in other words this is the family of Cur + + + align:start position:0% +in other words this is the family of Cur +curves that has the interesting slope + + align:start position:0% +curves that has the interesting slope + + + align:start position:0% +curves that has the interesting slope +property that we just discussed now you + + align:start position:0% +property that we just discussed now you + + + align:start position:0% +property that we just discussed now you +see again the reason I say that I wasn't + + align:start position:0% +see again the reason I say that I wasn't + + + align:start position:0% +see again the reason I say that I wasn't +too concerned about what this function + + align:start position:0% +too concerned about what this function + + + align:start position:0% +too concerned about what this function +actually was is notice that I was just + + align:start position:0% +actually was is notice that I was just + + + align:start position:0% +actually was is notice that I was just +pulling it out of the hat for you here + + align:start position:0% +pulling it out of the hat for you here + + + align:start position:0% +pulling it out of the hat for you here +anyway I said suppose we could find a + + align:start position:0% +anyway I said suppose we could find a + + + align:start position:0% +anyway I said suppose we could find a +function W such that DW was this the + + align:start position:0% +function W such that DW was this the + + + align:start position:0% +function W such that DW was this the +major question that comes up and how one + + align:start position:0% +major question that comes up and how one + + + align:start position:0% +major question that comes up and how one +uses differentials and the like is as + + align:start position:0% +uses differentials and the like is as + + + align:start position:0% +uses differentials and the like is as +follows suppose all I told you was that + + align:start position:0% +follows suppose all I told you was that + + + align:start position:0% +follows suppose all I told you was that +we had the differential X2 + y DX + 2xy + + align:start position:0% +we had the differential X2 + y DX + 2xy + + + align:start position:0% +we had the differential X2 + y DX + 2xy +Dy and I said to you find a function W + + align:start position:0% +Dy and I said to you find a function W + + + align:start position:0% +Dy and I said to you find a function W +such that DW will be X2 + Y2 DX plus 2xy + + align:start position:0% +such that DW will be X2 + Y2 DX plus 2xy + + + align:start position:0% +such that DW will be X2 + Y2 DX plus 2xy +Dy the key computational Aid in doing + + align:start position:0% +Dy the key computational Aid in doing + + + align:start position:0% +Dy the key computational Aid in doing +this involves the fact that if u and v + + align:start position:0% +this involves the fact that if u and v + + + align:start position:0% +this involves the fact that if u and v +are independent variables and it's + + align:start position:0% +are independent variables and it's + + + align:start position:0% +are independent variables and it's +crucial that they be independent that if + + align:start position:0% +crucial that they be independent that if + + + align:start position:0% +crucial that they be independent that if +Au U plus BV equals cuu plus DV it must + + align:start position:0% +Au U plus BV equals cuu plus DV it must + + + align:start position:0% +Au U plus BV equals cuu plus DV it must +be that a equals c and b equals D in + + align:start position:0% +be that a equals c and b equals D in + + + align:start position:0% +be that a equals c and b equals D in +other words the only way that two linear + + align:start position:0% +other words the only way that two linear + + + align:start position:0% +other words the only way that two linear +combinations of independent variables + + align:start position:0% +combinations of independent variables + + + align:start position:0% +combinations of independent variables +can be equal is if they're equal + + align:start position:0% +can be equal is if they're equal + + + align:start position:0% +can be equal is if they're equal +coefficient by coefficient you see the + + align:start position:0% +coefficient by coefficient you see the + + + align:start position:0% +coefficient by coefficient you see the +proof is very simple namely after all if + + align:start position:0% +proof is very simple namely after all if + + + align:start position:0% +proof is very simple namely after all if +u and v are independent variables why + + align:start position:0% +u and v are independent variables why + + + align:start position:0% +u and v are independent variables why +can't I pick V to be zero let U be any + + align:start position:0% +can't I pick V to be zero let U be any + + + align:start position:0% +can't I pick V to be zero let U be any +nonzero number then if V is zero when I + + align:start position:0% +nonzero number then if V is zero when I + + + align:start position:0% +nonzero number then if V is zero when I +equate these two it says Au U equals cuu + + align:start position:0% +equate these two it says Au U equals cuu + + + align:start position:0% +equate these two it says Au U equals cuu +Since U is not zero I can cancel and + + align:start position:0% +Since U is not zero I can cancel and + + + align:start position:0% +Since U is not zero I can cancel and +obtain that a equals c and in a similar + + align:start position:0% +obtain that a equals c and in a similar + + + align:start position:0% +obtain that a equals c and in a similar +way letting U equals z i have B V equal + + align:start position:0% +way letting U equals z i have B V equal + + + align:start position:0% +way letting U equals z i have B V equal +DV I can cancel the v's and get that b + + align:start position:0% +DV I can cancel the v's and get that b + + + align:start position:0% +DV I can cancel the v's and get that b +equals D but it's crucial that u and v + + align:start position:0% +equals D but it's crucial that u and v + + + align:start position:0% +equals D but it's crucial that u and v +be independent because if u and v are + + align:start position:0% +be independent because if u and v are + + + align:start position:0% +be independent because if u and v are +not independent how do I know that I can + + align:start position:0% +not independent how do I know that I can + + + align:start position:0% +not independent how do I know that I can +have U equal to zero when V is not zero + + align:start position:0% +have U equal to zero when V is not zero + + + align:start position:0% +have U equal to zero when V is not zero +for example let's suppose that V and U + + align:start position:0% +for example let's suppose that V and U + + + align:start position:0% +for example let's suppose that V and U +Were dependent suppose for example that + + align:start position:0% +Were dependent suppose for example that + + + align:start position:0% +Were dependent suppose for example that +V equals tce U observe in this case that + + align:start position:0% +V equals tce U observe in this case that + + + align:start position:0% +V equals tce U observe in this case that +9 U + 4 V since V is 2 U turns out to be + + align:start position:0% +9 U + 4 V since V is 2 U turns out to be + + + align:start position:0% +9 U + 4 V since V is 2 U turns out to be +17 U on the other hand 7 U + 5 V is 7 U + + align:start position:0% +17 U on the other hand 7 U + 5 V is 7 U + + + align:start position:0% +17 U on the other hand 7 U + 5 V is 7 U ++ 10 U which is also 17 U notice that 9 + + align:start position:0% ++ 10 U which is also 17 U notice that 9 + + + align:start position:0% ++ 10 U which is also 17 U notice that 9 +U + 4 v = 7 U + 5 V even though the + + align:start position:0% +U + 4 v = 7 U + 5 V even though the + + + align:start position:0% +U + 4 v = 7 U + 5 V even though the +coefficients don't line up as far as + + align:start position:0% +coefficients don't line up as far as + + + align:start position:0% +coefficients don't line up as far as +being equal a + + align:start position:0% +being equal a + + + align:start position:0% +being equal a +concern you see in other words notice + + align:start position:0% +concern you see in other words notice + + + align:start position:0% +concern you see in other words notice +that being able to equate things + + align:start position:0% +that being able to equate things + + + align:start position:0% +that being able to equate things +coefficient by coefficient hinges on the + + align:start position:0% +coefficient by coefficient hinges on the + + + align:start position:0% +coefficient by coefficient hinges on the +fact that the variables that we're + + align:start position:0% +fact that the variables that we're + + + align:start position:0% +fact that the variables that we're +dealing with are independent and the key + + align:start position:0% +dealing with are independent and the key + + + align:start position:0% +dealing with are independent and the key +thing going back to this problem is what + + align:start position:0% +thing going back to this problem is what + + + align:start position:0% +thing going back to this problem is what +were DX and Dy they were Delta X and + + align:start position:0% +were DX and Dy they were Delta X and + + + align:start position:0% +were DX and Dy they were Delta X and +Delta Y and as long as X and Y are + + align:start position:0% +Delta Y and as long as X and Y are + + + align:start position:0% +Delta Y and as long as X and Y are +independent variables certainly the + + align:start position:0% +independent variables certainly the + + + align:start position:0% +independent variables certainly the +change in X is independent can be done + + align:start position:0% +change in X is independent can be done + + + align:start position:0% +change in X is independent can be done +independently of the change in y in + + align:start position:0% +independently of the change in y in + + + align:start position:0% +independently of the change in y in +other words DX and Dy are independent + + align:start position:0% +other words DX and Dy are independent + + + align:start position:0% +other words DX and Dy are independent +variables so if we now say let's find + + align:start position:0% +variables so if we now say let's find + + + align:start position:0% +variables so if we now say let's find +that function W such that DW is X2 + y^2 + + align:start position:0% +that function W such that DW is X2 + y^2 + + + align:start position:0% +that function W such that DW is X2 + y^2 +DX is x + y^2 DX + 2x y Dy the one thing + + align:start position:0% +DX is x + y^2 DX + 2x y Dy the one thing + + + align:start position:0% +DX is x + y^2 DX + 2x y Dy the one thing +we know about DW if it exists by our + + align:start position:0% +we know about DW if it exists by our + + + align:start position:0% +we know about DW if it exists by our +basic definition of this section of this + + align:start position:0% +basic definition of this section of this + + + align:start position:0% +basic definition of this section of this +lecture is that DW is the partial of f + + align:start position:0% +lecture is that DW is the partial of f + + + align:start position:0% +lecture is that DW is the partial of f +respect to x * DX plus the partial of f + + align:start position:0% +respect to x * DX plus the partial of f + + + align:start position:0% +respect to x * DX plus the partial of f +respect to y * Dy since DX and Dy are + + align:start position:0% +respect to y * Dy since DX and Dy are + + + align:start position:0% +respect to y * Dy since DX and Dy are +independent variables the only way these + + align:start position:0% +independent variables the only way these + + + align:start position:0% +independent variables the only way these +two expressions can be identical is + + align:start position:0% +two expressions can be identical is + + + align:start position:0% +two expressions can be identical is +coefficient by coefficient that means in + + align:start position:0% +coefficient by coefficient that means in + + + align:start position:0% +coefficient by coefficient that means in +particular therefore that the partial of + + align:start position:0% +particular therefore that the partial of + + + align:start position:0% +particular therefore that the partial of +f respect to X which is the coefficient + + align:start position:0% +f respect to X which is the coefficient + + + align:start position:0% +f respect to X which is the coefficient +of DX here must be x^2 + y² which is the + + align:start position:0% +of DX here must be x^2 + y² which is the + + + align:start position:0% +of DX here must be x^2 + y² which is the +coefficient of DX here and similarly the + + align:start position:0% +coefficient of DX here and similarly the + + + align:start position:0% +coefficient of DX here and similarly the +partial of f respect to Y Must equal 2 X + + align:start position:0% +partial of f respect to Y Must equal 2 X + + + align:start position:0% +partial of f respect to Y Must equal 2 X +Y now armed with this information I can + + align:start position:0% +Y now armed with this information I can + + + align:start position:0% +Y now armed with this information I can +actually go out and construct F and the + + align:start position:0% +actually go out and construct F and the + + + align:start position:0% +actually go out and construct F and the +way I do this is remember as soon as I + + align:start position:0% +way I do this is remember as soon as I + + + align:start position:0% +way I do this is remember as soon as I +see the partial of f with respect to X + + align:start position:0% +see the partial of f with respect to X + + + align:start position:0% +see the partial of f with respect to X +it means I'm treating y as a constant if + + align:start position:0% +it means I'm treating y as a constant if + + + align:start position:0% +it means I'm treating y as a constant if +I'm treating y as a constant I just + + align:start position:0% +I'm treating y as a constant I just + + + align:start position:0% +I'm treating y as a constant I just +integrate this thing as if x were the + + align:start position:0% +integrate this thing as if x were the + + + align:start position:0% +integrate this thing as if x were the +only variable treating X as a variable + + align:start position:0% +only variable treating X as a variable + + + align:start position:0% +only variable treating X as a variable +and Y as a constant the integral of x^2 + + align:start position:0% +and Y as a constant the integral of x^2 + + + align:start position:0% +and Y as a constant the integral of x^2 +is 1/3 x cubed the integral of y^2 is + + align:start position:0% +is 1/3 x cubed the integral of y^2 is + + + align:start position:0% +is 1/3 x cubed the integral of y^2 is +simply y^2 X because Y is being treated + + align:start position:0% +simply y^2 X because Y is being treated + + + align:start position:0% +simply y^2 X because Y is being treated +as a constant and finally there must be + + align:start position:0% +as a constant and finally there must be + + + align:start position:0% +as a constant and finally there must be +a constant of integration but my + + align:start position:0% +a constant of integration but my + + + align:start position:0% +a constant of integration but my +constant now is any function of Y in + + align:start position:0% +constant now is any function of Y in + + + align:start position:0% +constant now is any function of Y in +other words if if I have any function of + + align:start position:0% +other words if if I have any function of + + + align:start position:0% +other words if if I have any function of +Y it's partial with respect to X by + + align:start position:0% +Y it's partial with respect to X by + + + align:start position:0% +Y it's partial with respect to X by +definition of X and Y being independent + + align:start position:0% +definition of X and Y being independent + + + align:start position:0% +definition of X and Y being independent +the partial of any function of Y respect + + align:start position:0% +the partial of any function of Y respect + + + align:start position:0% +the partial of any function of Y respect +to X is zero therefore my constant of + + align:start position:0% +to X is zero therefore my constant of + + + align:start position:0% +to X is zero therefore my constant of +integration in this case is a function + + align:start position:0% +integration in this case is a function + + + align:start position:0% +integration in this case is a function +of Y alone again to look at this in a + + align:start position:0% +of Y alone again to look at this in a + + + align:start position:0% +of Y alone again to look at this in a +different perspective what I'm saying is + + align:start position:0% +different perspective what I'm saying is + + + align:start position:0% +different perspective what I'm saying is +the most General function of two + + align:start position:0% +the most General function of two + + + align:start position:0% +the most General function of two +variables in the whole world whose + + align:start position:0% +variables in the whole world whose + + + align:start position:0% +variables in the whole world whose +derivative with respect to X is x^2 + + + align:start position:0% +derivative with respect to X is x^2 + + + + align:start position:0% +derivative with respect to X is x^2 + +y^2 is 1/3 XB + y^2 x plus a function of + + align:start position:0% +y^2 is 1/3 XB + y^2 x plus a function of + + + align:start position:0% +y^2 is 1/3 XB + y^2 x plus a function of +Y alone now all I don't know so far is + + align:start position:0% +Y alone now all I don't know so far is + + + align:start position:0% +Y alone now all I don't know so far is +what specific function of Y is G in + + align:start position:0% +what specific function of Y is G in + + + align:start position:0% +what specific function of Y is G in +other words I've determined F now up to + + align:start position:0% +other words I've determined F now up to + + + align:start position:0% +other words I've determined F now up to +this + + align:start position:0% +this + + + align:start position:0% +this +particular arbitrary constant of + + align:start position:0% +particular arbitrary constant of + + + align:start position:0% +particular arbitrary constant of +integration how do I get a hold of this + + align:start position:0% +integration how do I get a hold of this + + + align:start position:0% +integration how do I get a hold of this +thing notice that as yet I have not used + + align:start position:0% +thing notice that as yet I have not used + + + align:start position:0% +thing notice that as yet I have not used +a piece of information that tells me the + + align:start position:0% +a piece of information that tells me the + + + align:start position:0% +a piece of information that tells me the +partial of effort respect to Y is 2X Y + + align:start position:0% +partial of effort respect to Y is 2X Y + + + align:start position:0% +partial of effort respect to Y is 2X Y +and to utilize that piece of information + + align:start position:0% +and to utilize that piece of information + + + align:start position:0% +and to utilize that piece of information +what I do is I come to this equation and + + align:start position:0% +what I do is I come to this equation and + + + align:start position:0% +what I do is I come to this equation and +I say look at let me from here just + + align:start position:0% +I say look at let me from here just + + + align:start position:0% +I say look at let me from here just +differentiate this with respect to Y + + align:start position:0% +differentiate this with respect to Y + + + align:start position:0% +differentiate this with respect to Y +treating X as a constant if I do that + + align:start position:0% +treating X as a constant if I do that + + + align:start position:0% +treating X as a constant if I do that +this term drops out this term becomes + + align:start position:0% +this term drops out this term becomes + + + align:start position:0% +this term drops out this term becomes +2xy and this being a function of Y alone + + align:start position:0% +2xy and this being a function of Y alone + + + align:start position:0% +2xy and this being a function of Y alone +its derivative with respect to Y is just + + align:start position:0% +its derivative with respect to Y is just + + + align:start position:0% +its derivative with respect to Y is just +G Prime of Y so whatever f is f the Der + + align:start position:0% +G Prime of Y so whatever f is f the Der + + + align:start position:0% +G Prime of Y so whatever f is f the Der +of f with respect to Y is 2x y + G Prime + + align:start position:0% +of f with respect to Y is 2x y + G Prime + + + align:start position:0% +of f with respect to Y is 2x y + G Prime +of Y on the other hand we ALS also know + + align:start position:0% +of Y on the other hand we ALS also know + + + align:start position:0% +of Y on the other hand we ALS also know +that the parti of effort respect to Y is + + align:start position:0% +that the parti of effort respect to Y is + + + align:start position:0% +that the parti of effort respect to Y is +2xy consequently since these are two + + align:start position:0% +2xy consequently since these are two + + + align:start position:0% +2xy consequently since these are two +different expressions for the same + + align:start position:0% +different expressions for the same + + + align:start position:0% +different expressions for the same +quantity they must be equal equating + + align:start position:0% +quantity they must be equal equating + + + align:start position:0% +quantity they must be equal equating +these two the 2 X Y cancel we obtain + + align:start position:0% +these two the 2 X Y cancel we obtain + + + align:start position:0% +these two the 2 X Y cancel we obtain +that g Prime of Y is zero which means in + + align:start position:0% +that g Prime of Y is zero which means in + + + align:start position:0% +that g Prime of Y is zero which means in +this case that g of Y was a Bonafide + + align:start position:0% +this case that g of Y was a Bonafide + + + align:start position:0% +this case that g of Y was a Bonafide +constant that not only is G independent + + align:start position:0% +constant that not only is G independent + + + align:start position:0% +constant that not only is G independent +of X it's also independent of Y and we + + align:start position:0% +of X it's also independent of Y and we + + + align:start position:0% +of X it's also independent of Y and we +see that the most General function f + + align:start position:0% +see that the most General function f + + + align:start position:0% +see that the most General function f +which has the desired property is what + + align:start position:0% +which has the desired property is what + + + align:start position:0% +which has the desired property is what +all we have to do is now go back to this + + align:start position:0% +all we have to do is now go back to this + + + align:start position:0% +all we have to do is now go back to this +expression here which gave us the answer + + align:start position:0% +expression here which gave us the answer + + + align:start position:0% +expression here which gave us the answer +up to G of Y put this value of G of Y in + + align:start position:0% +up to G of Y put this value of G of Y in + + + align:start position:0% +up to G of Y put this value of G of Y in +and we see that the most General + + align:start position:0% +and we see that the most General + + + align:start position:0% +and we see that the most General +function whose total differential is x^2 + + align:start position:0% +function whose total differential is x^2 + + + align:start position:0% +function whose total differential is x^2 ++ y^2 DX + 2xy Dy is 1/3 x Cub + y^2 x + + + align:start position:0% ++ y^2 DX + 2xy Dy is 1/3 x Cub + y^2 x + + + + align:start position:0% ++ y^2 DX + 2xy Dy is 1/3 x Cub + y^2 x + +C and I guess there's a moral to this + + align:start position:0% +C and I guess there's a moral to this + + + align:start position:0% +C and I guess there's a moral to this +story after all you know when I did it + + align:start position:0% +story after all you know when I did it + + + align:start position:0% +story after all you know when I did it +the quick way I made a Kess + + align:start position:0% +the quick way I made a Kess + + + align:start position:0% +the quick way I made a Kess +computational mistake earlier in the + + align:start position:0% +computational mistake earlier in the + + + align:start position:0% +computational mistake earlier in the +lecture that sort of threw me off a bit + + align:start position:0% +lecture that sort of threw me off a bit + + + align:start position:0% +lecture that sort of threw me off a bit +and perplexed me + + align:start position:0% +and perplexed me + + + align:start position:0% +and perplexed me +and + + align:start position:0% +and + + + align:start position:0% +and +uh it seems it was Poetic Justice + + align:start position:0% +uh it seems it was Poetic Justice + + + align:start position:0% +uh it seems it was Poetic Justice +because you know when I took this method + + align:start position:0% +because you know when I took this method + + + align:start position:0% +because you know when I took this method +where we pretended we didn't know the + + align:start position:0% +where we pretended we didn't know the + + + align:start position:0% +where we pretended we didn't know the +answer in advance and just work the + + align:start position:0% +answer in advance and just work the + + + align:start position:0% +answer in advance and just work the +thing out systematically we came up with + + align:start position:0% +thing out systematically we came up with + + + align:start position:0% +thing out systematically we came up with +the right term in other words it should + + align:start position:0% +the right term in other words it should + + + align:start position:0% +the right term in other words it should +be y^2 X not YX s and that was what we + + align:start position:0% +be y^2 X not YX s and that was what we + + + align:start position:0% +be y^2 X not YX s and that was what we +saw should be the correct answer so + + align:start position:0% +saw should be the correct answer so + + + align:start position:0% +saw should be the correct answer so +maybe there's something to be said about + + align:start position:0% +maybe there's something to be said about + + + align:start position:0% +maybe there's something to be said about +doing things systematically after all + + align:start position:0% +doing things systematically after all + + + align:start position:0% +doing things systematically after all +you see if I can't win them all at least + + align:start position:0% +you see if I can't win them all at least + + + align:start position:0% +you see if I can't win them all at least +I have the gift of rationalizing to + + align:start position:0% +I have the gift of rationalizing to + + + align:start position:0% +I have the gift of rationalizing to +think that I win them all + + align:start position:0% +think that I win them all + + + align:start position:0% +think that I win them all +time after time I snatch defeat from the + + align:start position:0% +time after time I snatch defeat from the + + + align:start position:0% +time after time I snatch defeat from the +jaws of + + align:start position:0% +jaws of + + + align:start position:0% +jaws of +Victory no all right you know what I + + align:start position:0% +Victory no all right you know what I + + + align:start position:0% +Victory no all right you know what I +mean look at anyway the question that + + align:start position:0% +mean look at anyway the question that + + + align:start position:0% +mean look at anyway the question that +we've now solved is what we have worked + + align:start position:0% +we've now solved is what we have worked + + + align:start position:0% +we've now solved is what we have worked +out this routine notice that what we are + + align:start position:0% +out this routine notice that what we are + + + align:start position:0% +out this routine notice that what we are +really doing is the counterpart of + + align:start position:0% +really doing is the counterpart of + + + align:start position:0% +really doing is the counterpart of +calculus of a single variable that + + align:start position:0% +calculus of a single variable that + + + align:start position:0% +calculus of a single variable that +knowing what a partial is we can + + align:start position:0% +knowing what a partial is we can + + + align:start position:0% +knowing what a partial is we can +integrate with respect to that variable + + align:start position:0% +integrate with respect to that variable + + + align:start position:0% +integrate with respect to that variable +treating all the other variables as a + + align:start position:0% +treating all the other variables as a + + + align:start position:0% +treating all the other variables as a +constant and this is the general + + align:start position:0% +constant and this is the general + + + align:start position:0% +constant and this is the general +technique now let's summarize this more + + align:start position:0% +technique now let's summarize this more + + + align:start position:0% +technique now let's summarize this more +generally the general definition is this + + align:start position:0% +generally the general definition is this + + + align:start position:0% +generally the general definition is this +and by the way for the sake of + + align:start position:0% +and by the way for the sake of + + + align:start position:0% +and by the way for the sake of +conserving space I will now abbreviate m + + align:start position:0% +conserving space I will now abbreviate m + + + align:start position:0% +conserving space I will now abbreviate m +ofx y and N of X Y just by m and n but + + align:start position:0% +ofx y and N of X Y just by m and n but + + + align:start position:0% +ofx y and N of X Y just by m and n but +whenever I write M and N here it's + + align:start position:0% +whenever I write M and N here it's + + + align:start position:0% +whenever I write M and N here it's +assumed that M and N are functions of X + + align:start position:0% +assumed that M and N are functions of X + + + align:start position:0% +assumed that M and N are functions of X +and yo what we say is this MDX plus ndy + + align:start position:0% +and yo what we say is this MDX plus ndy + + + align:start position:0% +and yo what we say is this MDX plus ndy +which by the way by a previous + + align:start position:0% +which by the way by a previous + + + align:start position:0% +which by the way by a previous +definition is always a differential but + + align:start position:0% +definition is always a differential but + + + align:start position:0% +definition is always a differential but +this differential is called an exact + + align:start position:0% +this differential is called an exact + + + align:start position:0% +this differential is called an exact +differential if and only if there exists + + align:start position:0% +differential if and only if there exists + + + align:start position:0% +differential if and only if there exists +a function w f of XY such that DW is MDX + + align:start position:0% +a function w f of XY such that DW is MDX + + + align:start position:0% +a function w f of XY such that DW is MDX ++ mdy or in terms of our previous + + align:start position:0% ++ mdy or in terms of our previous + + + align:start position:0% ++ mdy or in terms of our previous +discussion what this means is what + + align:start position:0% +discussion what this means is what + + + align:start position:0% +discussion what this means is what +DW is also equal to F subx DX plus F + + align:start position:0% +DW is also equal to F subx DX plus F + + + align:start position:0% +DW is also equal to F subx DX plus F +suby Dy since X and Y are independent + + align:start position:0% +suby Dy since X and Y are independent + + + align:start position:0% +suby Dy since X and Y are independent +variables DX and Dy are independent + + align:start position:0% +variables DX and Dy are independent + + + align:start position:0% +variables DX and Dy are independent +variables so an alternative definition + + align:start position:0% +variables so an alternative definition + + + align:start position:0% +variables so an alternative definition +is what that MDX plus n Dy is an exact + + align:start position:0% +is what that MDX plus n Dy is an exact + + + align:start position:0% +is what that MDX plus n Dy is an exact +differential if there exists a function + + align:start position:0% +differential if there exists a function + + + align:start position:0% +differential if there exists a function +f such that the partial of f resp + + align:start position:0% +f such that the partial of f resp + + + align:start position:0% +f such that the partial of f resp +respect to X is M and the partial of f + + align:start position:0% +respect to X is M and the partial of f + + + align:start position:0% +respect to X is M and the partial of f +respect to Y is n now by the way let's + + align:start position:0% +respect to Y is n now by the way let's + + + align:start position:0% +respect to Y is n now by the way let's +just pause here for a moment you might + + align:start position:0% +just pause here for a moment you might + + + align:start position:0% +just pause here for a moment you might +suspect that with all the functions to + + align:start position:0% +suspect that with all the functions to + + + align:start position:0% +suspect that with all the functions to +choose from that no matter how M and N + + align:start position:0% +choose from that no matter how M and N + + + align:start position:0% +choose from that no matter how M and N +were given we're bound to find at least + + align:start position:0% +were given we're bound to find at least + + + align:start position:0% +were given we're bound to find at least +one function which satisfies I should + + align:start position:0% +one function which satisfies I should + + + align:start position:0% +one function which satisfies I should +put this in because you want both of + + align:start position:0% +put this in because you want both of + + + align:start position:0% +put this in because you want both of +these conditions fulfilled at the same + + align:start position:0% +these conditions fulfilled at the same + + + align:start position:0% +these conditions fulfilled at the same +time the amazing thing is that it is not + + align:start position:0% +time the amazing thing is that it is not + + + align:start position:0% +time the amazing thing is that it is not +always possible to find a function which + + align:start position:0% +always possible to find a function which + + + align:start position:0% +always possible to find a function which +has a given differential as its total + + align:start position:0% +has a given differential as its total + + + align:start position:0% +has a given differential as its total +differential in fact let me show you why + + align:start position:0% +differential in fact let me show you why + + + align:start position:0% +differential in fact let me show you why +if we can just do something a little bit + + align:start position:0% +if we can just do something a little bit + + + align:start position:0% +if we can just do something a little bit +tricky here let's suppose that the + + align:start position:0% +tricky here let's suppose that the + + + align:start position:0% +tricky here let's suppose that the +function f exists such that it's partial + + align:start position:0% +function f exists such that it's partial + + + align:start position:0% +function f exists such that it's partial +with respect to X as M and it's partial + + align:start position:0% +with respect to X as M and it's partial + + + align:start position:0% +with respect to X as M and it's partial +with respect to Y is n suppose that both + + align:start position:0% +with respect to Y is n suppose that both + + + align:start position:0% +with respect to Y is n suppose that both +of these happen to be differentiable + + align:start position:0% +of these happen to be differentiable + + + align:start position:0% +of these happen to be differentiable +take the partial of f subx with respect + + align:start position:0% +take the partial of f subx with respect + + + align:start position:0% +take the partial of f subx with respect +to Y that tells me that f subx y is the + + align:start position:0% +to Y that tells me that f subx y is the + + + align:start position:0% +to Y that tells me that f subx y is the +partial of M with respect to Y let's + + align:start position:0% +partial of M with respect to Y let's + + + align:start position:0% +partial of M with respect to Y let's +take the partial of f suby with respect + + align:start position:0% +take the partial of f suby with respect + + + align:start position:0% +take the partial of f suby with respect +to X that tells me that the of f sub y + + align:start position:0% +to X that tells me that the of f sub y + + + align:start position:0% +to X that tells me that the of f sub y +respect to X is n subx in other words + + align:start position:0% +respect to X is n subx in other words + + + align:start position:0% +respect to X is n subx in other words +fyx equal n subx now if f is continu see + + align:start position:0% +fyx equal n subx now if f is continu see + + + align:start position:0% +fyx equal n subx now if f is continu see +if if we have the right amount of + + align:start position:0% +if if we have the right amount of + + + align:start position:0% +if if we have the right amount of +continuity and differentiability that + + align:start position:0% +continuity and differentiability that + + + align:start position:0% +continuity and differentiability that +we've talked about in previous lectures + + align:start position:0% +we've talked about in previous lectures + + + align:start position:0% +we've talked about in previous lectures +notice that for most well defined + + align:start position:0% +notice that for most well defined + + + align:start position:0% +notice that for most well defined +functions in particular if these two + + align:start position:0% +functions in particular if these two + + + align:start position:0% +functions in particular if these two +partials see we don't know what f is + + align:start position:0% +partials see we don't know what f is + + + align:start position:0% +partials see we don't know what f is +we're trying to find F and we're + + align:start position:0% +we're trying to find F and we're + + + align:start position:0% +we're trying to find F and we're +assuming it exists the thing that's + + align:start position:0% +assuming it exists the thing that's + + + align:start position:0% +assuming it exists the thing that's +given in our definition M and N so to + + align:start position:0% +given in our definition M and N so to + + + align:start position:0% +given in our definition M and N so to +this more succinctly if it turns out + + align:start position:0% +this more succinctly if it turns out + + + align:start position:0% +this more succinctly if it turns out +that the partial of M respect to Y and + + align:start position:0% +that the partial of M respect to Y and + + + align:start position:0% +that the partial of M respect to Y and +the partial of n with respect to X + + align:start position:0% +the partial of n with respect to X + + + align:start position:0% +the partial of n with respect to X +happen to be continuous functions notice + + align:start position:0% +happen to be continuous functions notice + + + align:start position:0% +happen to be continuous functions notice +that these two things are equal and in + + align:start position:0% +that these two things are equal and in + + + align:start position:0% +that these two things are equal and in +particular that means that the partial + + align:start position:0% +particular that means that the partial + + + align:start position:0% +particular that means that the partial +of n with respect to Y has to equal the + + align:start position:0% +of n with respect to Y has to equal the + + + align:start position:0% +of n with respect to Y has to equal the +partial of n with respect to X coming + + align:start position:0% +partial of n with respect to X coming + + + align:start position:0% +partial of n with respect to X coming +back to the original definition here + + align:start position:0% +back to the original definition here + + + align:start position:0% +back to the original definition here +this is a rather amazing thing it says + + align:start position:0% +this is a rather amazing thing it says + + + align:start position:0% +this is a rather amazing thing it says +that if this differential is exact if + + align:start position:0% +that if this differential is exact if + + + align:start position:0% +that if this differential is exact if +you take the coefficient of DX see think + + align:start position:0% +you take the coefficient of DX see think + + + align:start position:0% +you take the coefficient of DX see think +of M as being the coefficient of DX and + + align:start position:0% +of M as being the coefficient of DX and + + + align:start position:0% +of M as being the coefficient of DX and +n as being the coefficient of Dy if you + + align:start position:0% +n as being the coefficient of Dy if you + + + align:start position:0% +n as being the coefficient of Dy if you +take the coefficient of DX and + + align:start position:0% +take the coefficient of DX and + + + align:start position:0% +take the coefficient of DX and +differentiate that with respect to Y you + + align:start position:0% +differentiate that with respect to Y you + + + align:start position:0% +differentiate that with respect to Y you +must get the same + + align:start position:0% +must get the same + + + align:start position:0% +must get the same +answer as if you took the coefficient of + + align:start position:0% +answer as if you took the coefficient of + + + align:start position:0% +answer as if you took the coefficient of +Dy and differentiated that with respect + + align:start position:0% +Dy and differentiated that with respect + + + align:start position:0% +Dy and differentiated that with respect +to X that's an amazing coincidence if + + align:start position:0% +to X that's an amazing coincidence if + + + align:start position:0% +to X that's an amazing coincidence if +that happens given two arbitrary + + align:start position:0% +that happens given two arbitrary + + + align:start position:0% +that happens given two arbitrary +functions this indeed won't happen now + + align:start position:0% +functions this indeed won't happen now + + + align:start position:0% +functions this indeed won't happen now +before I show you that let's summarize + + align:start position:0% +before I show you that let's summarize + + + align:start position:0% +before I show you that let's summarize +this in words written down so that I + + align:start position:0% +this in words written down so that I + + + align:start position:0% +this in words written down so that I +make sure that you understand what I'm + + align:start position:0% +make sure that you understand what I'm + + + align:start position:0% +make sure that you understand what I'm +saying what I'm saying is if the partial + + align:start position:0% +saying what I'm saying is if the partial + + + align:start position:0% +saying what I'm saying is if the partial +of M with respect to Y and the partial + + align:start position:0% +of M with respect to Y and the partial + + + align:start position:0% +of M with respect to Y and the partial +of n with respect to X are continuous + + align:start position:0% +of n with respect to X are continuous + + + align:start position:0% +of n with respect to X are continuous +then if MDX plus ndy is exact the + + align:start position:0% +then if MDX plus ndy is exact the + + + align:start position:0% +then if MDX plus ndy is exact the +implication is that the partial of n + + align:start position:0% +implication is that the partial of n + + + align:start position:0% +implication is that the partial of n +with respect to Y Must equal the partial + + align:start position:0% +with respect to Y Must equal the partial + + + align:start position:0% +with respect to Y Must equal the partial +of n with respect to X and to invert the + + align:start position:0% +of n with respect to X and to invert the + + + align:start position:0% +of n with respect to X and to invert the +emphasis here another way of saying this + + align:start position:0% +emphasis here another way of saying this + + + align:start position:0% +emphasis here another way of saying this +is that if the partial of n with respect + + align:start position:0% +is that if the partial of n with respect + + + align:start position:0% +is that if the partial of n with respect +to Y is not equal to the partial of n + + align:start position:0% +to Y is not equal to the partial of n + + + align:start position:0% +to Y is not equal to the partial of n +with respect to X then MDX plus ndy is + + align:start position:0% +with respect to X then MDX plus ndy is + + + align:start position:0% +with respect to X then MDX plus ndy is +not exact and let me show you that by + + align:start position:0% +not exact and let me show you that by + + + align:start position:0% +not exact and let me show you that by +means of an example let's look at the + + align:start position:0% +means of an example let's look at the + + + align:start position:0% +means of an example let's look at the +differential a very simple looking one + + align:start position:0% +differential a very simple looking one + + + align:start position:0% +differential a very simple looking one +in fact it looks far less complicated + + align:start position:0% +in fact it looks far less complicated + + + align:start position:0% +in fact it looks far less complicated +than the expression that we worked with + + align:start position:0% +than the expression that we worked with + + + align:start position:0% +than the expression that we worked with +previously let's look simply at Y dxus + + align:start position:0% +previously let's look simply at Y dxus + + + align:start position:0% +previously let's look simply at Y dxus +xdy in this problem the coefficient of + + align:start position:0% +xdy in this problem the coefficient of + + + align:start position:0% +xdy in this problem the coefficient of +DX is y that plays the role of M the + + align:start position:0% +DX is y that plays the role of M the + + + align:start position:0% +DX is y that plays the role of M the +coefficient of Dy is minus X that's what + + align:start position:0% +coefficient of Dy is minus X that's what + + + align:start position:0% +coefficient of Dy is minus X that's what +we're calling n you see and the partial + + align:start position:0% +we're calling n you see and the partial + + + align:start position:0% +we're calling n you see and the partial +of M with respect to Y is just the + + align:start position:0% +of M with respect to Y is just the + + + align:start position:0% +of M with respect to Y is just the +partial of Y with respect to Y which is + + align:start position:0% +partial of Y with respect to Y which is + + + align:start position:0% +partial of Y with respect to Y which is +one the partial of n with respect to X + + align:start position:0% +one the partial of n with respect to X + + + align:start position:0% +one the partial of n with respect to X +is the partial of - x with respect to X + + align:start position:0% +is the partial of - x with respect to X + + + align:start position:0% +is the partial of - x with respect to X +which is minus1 since 1 is not equal to + + align:start position:0% +which is minus1 since 1 is not equal to + + + align:start position:0% +which is minus1 since 1 is not equal to +minus1 this is not exact because if it + + align:start position:0% +minus1 this is not exact because if it + + + align:start position:0% +minus1 this is not exact because if it +were exact these two partials would have + + align:start position:0% +were exact these two partials would have + + + align:start position:0% +were exact these two partials would have +to be equal what does it mean to say if + + align:start position:0% +to be equal what does it mean to say if + + + align:start position:0% +to be equal what does it mean to say if +this is not exact what it means is that + + align:start position:0% +this is not exact what it means is that + + + align:start position:0% +this is not exact what it means is that +there is not a single function in the + + align:start position:0% +there is not a single function in the + + + align:start position:0% +there is not a single function in the +whole world that has the property that + + align:start position:0% +whole world that has the property that + + + align:start position:0% +whole world that has the property that +it's partial with respect to X is y and + + align:start position:0% +it's partial with respect to X is y and + + + align:start position:0% +it's partial with respect to X is y and +it's partial with respect to Y is minus + + align:start position:0% +it's partial with respect to Y is minus + + + align:start position:0% +it's partial with respect to Y is minus +X you can look + + align:start position:0% +X you can look + + + align:start position:0% +X you can look +forever and not only won't you find one + + align:start position:0% +forever and not only won't you find one + + + align:start position:0% +forever and not only won't you find one +there isn't one and by the way let me + + align:start position:0% +there isn't one and by the way let me + + + align:start position:0% +there isn't one and by the way let me +make one very quick aside here notice + + align:start position:0% +make one very quick aside here notice + + + align:start position:0% +make one very quick aside here notice +the difference between saying you can't + + align:start position:0% +the difference between saying you can't + + + align:start position:0% +the difference between saying you can't +find one and there isn't one there may + + align:start position:0% +find one and there isn't one there may + + + align:start position:0% +find one and there isn't one there may +be one and you just not lucky enough to + + align:start position:0% +be one and you just not lucky enough to + + + align:start position:0% +be one and you just not lucky enough to +find it I'm saying that the reason you + + align:start position:0% +find it I'm saying that the reason you + + + align:start position:0% +find it I'm saying that the reason you +don't find an answer here unless you + + align:start position:0% +don't find an answer here unless you + + + align:start position:0% +don't find an answer here unless you +make a mistake and think you found an + + align:start position:0% +make a mistake and think you found an + + + align:start position:0% +make a mistake and think you found an +answer the reason you don't find an + + align:start position:0% +answer the reason you don't find an + + + align:start position:0% +answer the reason you don't find an +answer is there is none and how can I + + align:start position:0% +answer is there is none and how can I + + + align:start position:0% +answer is there is none and how can I +show you that there is none well the + + align:start position:0% +show you that there is none well the + + + align:start position:0% +show you that there is none well the +best way is to do the same thing that we + + align:start position:0% +best way is to do the same thing that we + + + align:start position:0% +best way is to do the same thing that we +did in the previous example and see + + align:start position:0% +did in the previous example and see + + + align:start position:0% +did in the previous example and see +something go wrong let's suppose that + + align:start position:0% +something go wrong let's suppose that + + + align:start position:0% +something go wrong let's suppose that +we're an answer to this well if the + + align:start position:0% +we're an answer to this well if the + + + align:start position:0% +we're an answer to this well if the +partial of effort respect to x equals y + + align:start position:0% +partial of effort respect to x equals y + + + align:start position:0% +partial of effort respect to x equals y +let me integrate this with respect to X + + align:start position:0% +let me integrate this with respect to X + + + align:start position:0% +let me integrate this with respect to X +treating y as a constant it means that + + align:start position:0% +treating y as a constant it means that + + + align:start position:0% +treating y as a constant it means that +the function that I'm looking for must + + align:start position:0% +the function that I'm looking for must + + + align:start position:0% +the function that I'm looking for must +have what form it's x * y plus some + + align:start position:0% +have what form it's x * y plus some + + + align:start position:0% +have what form it's x * y plus some +function of Y alone and now we say gee + + align:start position:0% +function of Y alone and now we say gee + + + align:start position:0% +function of Y alone and now we say gee +we're in pretty good shape all we've got + + align:start position:0% +we're in pretty good shape all we've got + + + align:start position:0% +we're in pretty good shape all we've got +to do is find what G of Y is and we're + + align:start position:0% +to do is find what G of Y is and we're + + + align:start position:0% +to do is find what G of Y is and we're +home free let's continue to mimic what + + align:start position:0% +home free let's continue to mimic what + + + align:start position:0% +home free let's continue to mimic what +we did before knowing this I can take + + align:start position:0% +we did before knowing this I can take + + + align:start position:0% +we did before knowing this I can take +the partial of this with respect to Y + + align:start position:0% +the partial of this with respect to Y + + + align:start position:0% +the partial of this with respect to Y +okay which is what if I take the partial + + align:start position:0% +okay which is what if I take the partial + + + align:start position:0% +okay which is what if I take the partial +of this with respect to Y this is + + align:start position:0% +of this with respect to Y this is + + + align:start position:0% +of this with respect to Y this is +F suby is X Plus G Prime of Y all right + + align:start position:0% +F suby is X Plus G Prime of Y all right + + + align:start position:0% +F suby is X Plus G Prime of Y all right +now this is the partial of f with + + align:start position:0% +now this is the partial of f with + + + align:start position:0% +now this is the partial of f with +respect to Y computed from here I know + + align:start position:0% +respect to Y computed from here I know + + + align:start position:0% +respect to Y computed from here I know +by hypothesis that the function I'm + + align:start position:0% +by hypothesis that the function I'm + + + align:start position:0% +by hypothesis that the function I'm +looking for must have its partial with + + align:start position:0% +looking for must have its partial with + + + align:start position:0% +looking for must have its partial with +respect to y equal to this consequently + + align:start position:0% +respect to y equal to this consequently + + + align:start position:0% +respect to y equal to this consequently +these two expressions must be equal and + + align:start position:0% +these two expressions must be equal and + + + align:start position:0% +these two expressions must be equal and +equating these two expressions says that + + align:start position:0% +equating these two expressions says that + + + align:start position:0% +equating these two expressions says that +g Prime of Y see x + G Prime of Y Must + + align:start position:0% +g Prime of Y see x + G Prime of Y Must + + + align:start position:0% +g Prime of Y see x + G Prime of Y Must +equal - x transposing says that g Prime + + align:start position:0% +equal - x transposing says that g Prime + + + align:start position:0% +equal - x transposing says that g Prime +of Y is - 2 X and this is a + + align:start position:0% +of Y is - 2 X and this is a + + + align:start position:0% +of Y is - 2 X and this is a +contradiction because look at G Prime of + + align:start position:0% +contradiction because look at G Prime of + + + align:start position:0% +contradiction because look at G Prime of +Y is a function of Y alone and here we + + align:start position:0% +Y is a function of Y alone and here we + + + align:start position:0% +Y is a function of Y alone and here we +have it's equal to some function of X or + + align:start position:0% +have it's equal to some function of X or + + + align:start position:0% +have it's equal to some function of X or +another way of looking at it this says + + align:start position:0% +another way of looking at it this says + + + align:start position:0% +another way of looking at it this says +that X depends on y x is some function + + align:start position:0% +that X depends on y x is some function + + + align:start position:0% +that X depends on y x is some function +of Y which is a contradiction since we + + align:start position:0% +of Y which is a contradiction since we + + + align:start position:0% +of Y which is a contradiction since we +assumed that X and Y are independent + + align:start position:0% +assumed that X and Y are independent + + + align:start position:0% +assumed that X and Y are independent +variables by the way just as a quick + + align:start position:0% +variables by the way just as a quick + + + align:start position:0% +variables by the way just as a quick +aside notice that in the case where we + + align:start position:0% +aside notice that in the case where we + + + align:start position:0% +aside notice that in the case where we +were able to succeed at this namely the + + align:start position:0% +were able to succeed at this namely the + + + align:start position:0% +were able to succeed at this namely the +the previous example X2 + y DX + 2x y d + + align:start position:0% +the previous example X2 + y DX + 2x y d + + + align:start position:0% +the previous example X2 + y DX + 2x y d +y m was x^2 + y^2 n was 2x y notice that + + align:start position:0% +y m was x^2 + y^2 n was 2x y notice that + + + align:start position:0% +y m was x^2 + y^2 n was 2x y notice that +the partial of M with respect to Y is 2 + + align:start position:0% +the partial of M with respect to Y is 2 + + + align:start position:0% +the partial of M with respect to Y is 2 +Y and the partial of n with respect to X + + align:start position:0% +Y and the partial of n with respect to X + + + align:start position:0% +Y and the partial of n with respect to X +is also 2 y so it seems that the + + align:start position:0% +is also 2 y so it seems that the + + + align:start position:0% +is also 2 y so it seems that the +deciding factor really seems to be that + + align:start position:0% +deciding factor really seems to be that + + + align:start position:0% +deciding factor really seems to be that +the partial of n with respect to Y has + + align:start position:0% +the partial of n with respect to Y has + + + align:start position:0% +the partial of n with respect to Y has +to equal the partial of n with respect + + align:start position:0% +to equal the partial of n with respect + + + align:start position:0% +to equal the partial of n with respect +to X and the major result is and I + + align:start position:0% +to X and the major result is and I + + + align:start position:0% +to X and the major result is and I +didn't write this in because I didn't + + align:start position:0% +didn't write this in because I didn't + + + align:start position:0% +didn't write this in because I didn't +want to use up too much space but this + + align:start position:0% +want to use up too much space but this + + + align:start position:0% +want to use up too much space but this +is emphasized in the text and in the + + align:start position:0% +is emphasized in the text and in the + + + align:start position:0% +is emphasized in the text and in the +exercises if + + align:start position:0% +exercises if + + + align:start position:0% +exercises if +MN M suby and M subx all exist and are + + align:start position:0% +MN M suby and M subx all exist and are + + + align:start position:0% +MN M suby and M subx all exist and are +continuous then not only can we say that + + align:start position:0% +continuous then not only can we say that + + + align:start position:0% +continuous then not only can we say that +MDX plus ndy is exact implies this part + + align:start position:0% +MDX plus ndy is exact implies this part + + + align:start position:0% +MDX plus ndy is exact implies this part +but we can do the converse too that in + + align:start position:0% +but we can do the converse too that in + + + align:start position:0% +but we can do the converse too that in +particular if m suby equals m subx we + + align:start position:0% +particular if m suby equals m subx we + + + align:start position:0% +particular if m suby equals m subx we +can conclude that this is exact and the + + align:start position:0% +can conclude that this is exact and the + + + align:start position:0% +can conclude that this is exact and the +reason for this I'll go through this + + align:start position:0% +reason for this I'll go through this + + + align:start position:0% +reason for this I'll go through this +very quickly because the proof is given + + align:start position:0% +very quickly because the proof is given + + + align:start position:0% +very quickly because the proof is given +in the text I just want to show you the + + align:start position:0% +in the text I just want to show you the + + + align:start position:0% +in the text I just want to show you the +highlights of what happens is what + + align:start position:0% +highlights of what happens is what + + + align:start position:0% +highlights of what happens is what +really happened when we tried to con + + align:start position:0% +really happened when we tried to con + + + align:start position:0% +really happened when we tried to con +struct F that made things work in one + + align:start position:0% +struct F that made things work in one + + + align:start position:0% +struct F that made things work in one +case but not in the other I think the + + align:start position:0% +case but not in the other I think the + + + align:start position:0% +case but not in the other I think the +best way to do this is to work + + align:start position:0% +best way to do this is to work + + + align:start position:0% +best way to do this is to work +abstractly here without specifying what + + align:start position:0% +abstractly here without specifying what + + + align:start position:0% +abstractly here without specifying what +M and N are and see what happens what we + + align:start position:0% +M and N are and see what happens what we + + + align:start position:0% +M and N are and see what happens what we +were trying to solve was a pair of + + align:start position:0% +were trying to solve was a pair of + + + align:start position:0% +were trying to solve was a pair of +equations we was trying to find F such + + align:start position:0% +equations we was trying to find F such + + + align:start position:0% +equations we was trying to find F such +as the partial of f respect to X is M + + align:start position:0% +as the partial of f respect to X is M + + + align:start position:0% +as the partial of f respect to X is M +partial of f respect to Y is n the first + + align:start position:0% +partial of f respect to Y is n the first + + + align:start position:0% +partial of f respect to Y is n the first +thing that we did was we treated y as a + + align:start position:0% +thing that we did was we treated y as a + + + align:start position:0% +thing that we did was we treated y as a +constant and integrated this with + + align:start position:0% +constant and integrated this with + + + align:start position:0% +constant and integrated this with +respect to X well I can't do this + + align:start position:0% +respect to X well I can't do this + + + align:start position:0% +respect to X well I can't do this +specifically because I don't know what M + + align:start position:0% +specifically because I don't know what M + + + align:start position:0% +specifically because I don't know what M +is so let me just just put the integral + + align:start position:0% +is so let me just just put the integral + + + align:start position:0% +is so let me just just put the integral +sign in here to say what I'm integrating + + align:start position:0% +sign in here to say what I'm integrating + + + align:start position:0% +sign in here to say what I'm integrating +this with respect to X treating y as a + + align:start position:0% +this with respect to X treating y as a + + + align:start position:0% +this with respect to X treating y as a +constant that's some function of X and Y + + align:start position:0% +constant that's some function of X and Y + + + align:start position:0% +constant that's some function of X and Y +you see over here see m is a function of + + align:start position:0% +you see over here see m is a function of + + + align:start position:0% +you see over here see m is a function of +X and Y I'm holding y constant I'm + + align:start position:0% +X and Y I'm holding y constant I'm + + + align:start position:0% +X and Y I'm holding y constant I'm +integrating this plus a constant of + + align:start position:0% +integrating this plus a constant of + + + align:start position:0% +integrating this plus a constant of +integration which depends only on y all + + align:start position:0% +integration which depends only on y all + + + align:start position:0% +integration which depends only on y all +right same as before what was my next + + align:start position:0% +right same as before what was my next + + + align:start position:0% +right same as before what was my next +step I took the partial of this with + + align:start position:0% +step I took the partial of this with + + + align:start position:0% +step I took the partial of this with +respect to F with respect to Y and I was + + align:start position:0% +respect to F with respect to Y and I was + + + align:start position:0% +respect to F with respect to Y and I was +going to compare that with what I knew + + align:start position:0% +going to compare that with what I knew + + + align:start position:0% +going to compare that with what I knew +the partial of f respect to Y had to be + + align:start position:0% +the partial of f respect to Y had to be + + + align:start position:0% +the partial of f respect to Y had to be +namely n so I then took what the partial + + align:start position:0% +namely n so I then took what the partial + + + align:start position:0% +namely n so I then took what the partial +of this with respect to Y that gave me + + align:start position:0% +of this with respect to Y that gave me + + + align:start position:0% +of this with respect to Y that gave me +the partial of this integral with + + align:start position:0% +the partial of this integral with + + + align:start position:0% +the partial of this integral with +respect to Y plus G Prime of Y and + + align:start position:0% +respect to Y plus G Prime of Y and + + + align:start position:0% +respect to Y plus G Prime of Y and +equating that to N I get that g Prime of + + align:start position:0% +equating that to N I get that g Prime of + + + align:start position:0% +equating that to N I get that g Prime of +Y was n minus the partial respect to Y + + align:start position:0% +Y was n minus the partial respect to Y + + + align:start position:0% +Y was n minus the partial respect to Y +integral M DX and again don't be alarmed + + align:start position:0% +integral M DX and again don't be alarmed + + + align:start position:0% +integral M DX and again don't be alarmed +by this expression if M had been given + + align:start position:0% +by this expression if M had been given + + + align:start position:0% +by this expression if M had been given +explicitly I would have solved + + align:start position:0% +explicitly I would have solved + + + align:start position:0% +explicitly I would have solved +explicitly for what this function was + + align:start position:0% +explicitly for what this function was + + + align:start position:0% +explicitly for what this function was +the key point is to notice that this + + align:start position:0% +the key point is to notice that this + + + align:start position:0% +the key point is to notice that this +side here is independent of x + + align:start position:0% +side here is independent of x + + + align:start position:0% +side here is independent of x +consequently this equation will be a + + align:start position:0% +consequently this equation will be a + + + align:start position:0% +consequently this equation will be a +contradiction unless the right hand side + + align:start position:0% +contradiction unless the right hand side + + + align:start position:0% +contradiction unless the right hand side +is a function of X in other words I mean + + align:start position:0% +is a function of X in other words I mean + + + align:start position:0% +is a function of X in other words I mean +is independent of X in other words we + + align:start position:0% +is independent of X in other words we + + + align:start position:0% +is independent of X in other words we +have determined f up to this function G + + align:start position:0% +have determined f up to this function G + + + align:start position:0% +have determined f up to this function G +of Y and what's going to happen is we + + align:start position:0% +of Y and what's going to happen is we + + + align:start position:0% +of Y and what's going to happen is we +are going to be able to compute G of Y + + align:start position:0% +are going to be able to compute G of Y + + + align:start position:0% +are going to be able to compute G of Y +if this expression is independent of X + + align:start position:0% +if this expression is independent of X + + + align:start position:0% +if this expression is independent of X +namely just by integrating this but if + + align:start position:0% +namely just by integrating this but if + + + align:start position:0% +namely just by integrating this but if +if G of Y is not independent of X we are + + align:start position:0% +if G of Y is not independent of X we are + + + align:start position:0% +if G of Y is not independent of X we are +in trouble it means that it's not going + + align:start position:0% +in trouble it means that it's not going + + + align:start position:0% +in trouble it means that it's not going +to exist the key key step is is this + + align:start position:0% +to exist the key key step is is this + + + align:start position:0% +to exist the key key step is is this +independent of X and the answer is the + + align:start position:0% +independent of X and the answer is the + + + align:start position:0% +independent of X and the answer is the +best way to find out in terms of + + align:start position:0% +best way to find out in terms of + + + align:start position:0% +best way to find out in terms of +calculus is to take its derivative with + + align:start position:0% +calculus is to take its derivative with + + + align:start position:0% +calculus is to take its derivative with +respect to X if this depends on y alone + + align:start position:0% +respect to X if this depends on y alone + + + align:start position:0% +respect to X if this depends on y alone +its partial with respect to X must be + + align:start position:0% +its partial with respect to X must be + + + align:start position:0% +its partial with respect to X must be +zero in other words if this partial with + + align:start position:0% +zero in other words if this partial with + + + align:start position:0% +zero in other words if this partial with +respect to X is not zero it means that + + align:start position:0% +respect to X is not zero it means that + + + align:start position:0% +respect to X is not zero it means that +this expression varies with X at any + + align:start position:0% +this expression varies with X at any + + + align:start position:0% +this expression varies with X at any +rate to see what this derivative is we + + align:start position:0% +rate to see what this derivative is we + + + align:start position:0% +rate to see what this derivative is we +just differentiate term by term and then + + align:start position:0% +just differentiate term by term and then + + + align:start position:0% +just differentiate term by term and then +we say you know it's rather interesting + + align:start position:0% +we say you know it's rather interesting + + + align:start position:0% +we say you know it's rather interesting +if this thing had been + + align:start position:0% +if this thing had been + + + align:start position:0% +if this thing had been +first notice that if you integrate with + + align:start position:0% +first notice that if you integrate with + + + align:start position:0% +first notice that if you integrate with +respect to X and then differentiate with + + align:start position:0% +respect to X and then differentiate with + + + align:start position:0% +respect to X and then differentiate with +respect to X you wind up with just the + + align:start position:0% +respect to X you wind up with just the + + + align:start position:0% +respect to X you wind up with just the +integrand well again if we have enough + + align:start position:0% +integrand well again if we have enough + + + align:start position:0% +integrand well again if we have enough +continuity the order of differentiation + + align:start position:0% +continuity the order of differentiation + + + align:start position:0% +continuity the order of differentiation +is irrelevant we can reverse the order + + align:start position:0% +is irrelevant we can reverse the order + + + align:start position:0% +is irrelevant we can reverse the order +without changing anything if we now + + align:start position:0% +without changing anything if we now + + + align:start position:0% +without changing anything if we now +interchange this order take the partial + + align:start position:0% +interchange this order take the partial + + + align:start position:0% +interchange this order take the partial +first with respect to X that will give + + align:start position:0% +first with respect to X that will give + + + align:start position:0% +first with respect to X that will give +us just m and the partial of M with + + align:start position:0% +us just m and the partial of M with + + + align:start position:0% +us just m and the partial of M with +respect to Y is just a partial of M with + + align:start position:0% +respect to Y is just a partial of M with + + + align:start position:0% +respect to Y is just a partial of M with +respect to Y of course what we're saying + + align:start position:0% +respect to Y of course what we're saying + + + align:start position:0% +respect to Y of course what we're saying +is that from this step we get the this + + align:start position:0% +is that from this step we get the this + + + align:start position:0% +is that from this step we get the this +step and this in turn implies this + + align:start position:0% +step and this in turn implies this + + + align:start position:0% +step and this in turn implies this +notice that the only way that this can + + align:start position:0% +notice that the only way that this can + + + align:start position:0% +notice that the only way that this can +be + + align:start position:0% +be + + + align:start position:0% +be +zero is if the partial of n with respect + + align:start position:0% +zero is if the partial of n with respect + + + align:start position:0% +zero is if the partial of n with respect +to x equals the partial of M with + + align:start position:0% +to x equals the partial of M with + + + align:start position:0% +to x equals the partial of M with +respect to Y so in summary then this is + + align:start position:0% +respect to Y so in summary then this is + + + align:start position:0% +respect to Y so in summary then this is +a very interesting device it tells us + + align:start position:0% +a very interesting device it tells us + + + align:start position:0% +a very interesting device it tells us +how to tell whether a differential is + + align:start position:0% +how to tell whether a differential is + + + align:start position:0% +how to tell whether a differential is +exact and the proof is very nice in this + + align:start position:0% +exact and the proof is very nice in this + + + align:start position:0% +exact and the proof is very nice in this +case because the proof exactly imitates + + align:start position:0% +case because the proof exactly imitates + + + align:start position:0% +case because the proof exactly imitates +how we construct the function f if it + + align:start position:0% +how we construct the function f if it + + + align:start position:0% +how we construct the function f if it +turns out to be exact but but the point + + align:start position:0% +turns out to be exact but but the point + + + align:start position:0% +turns out to be exact but but the point +is if given MDX plus ndy if the partial + + align:start position:0% +is if given MDX plus ndy if the partial + + + align:start position:0% +is if given MDX plus ndy if the partial +of M with respect to Y is not equal to + + align:start position:0% +of M with respect to Y is not equal to + + + align:start position:0% +of M with respect to Y is not equal to +the partial of M with respect to X + + align:start position:0% +the partial of M with respect to X + + + align:start position:0% +the partial of M with respect to X +there's no hope that the function will + + align:start position:0% +there's no hope that the function will + + + align:start position:0% +there's no hope that the function will +be exact the differential will be exact + + align:start position:0% +be exact the differential will be exact + + + align:start position:0% +be exact the differential will be exact +any rate we will have sufficient + + align:start position:0% +any rate we will have sufficient + + + align:start position:0% +any rate we will have sufficient +exercises for drill and how one uses + + align:start position:0% +exercises for drill and how one uses + + + align:start position:0% +exercises for drill and how one uses +exact differentials this concludes block + + align:start position:0% +exact differentials this concludes block + + + align:start position:0% +exact differentials this concludes block +three of our material our next block of + + align:start position:0% +three of our material our next block of + + + align:start position:0% +three of our material our next block of +material which will cons which will + + align:start position:0% +material which will cons which will + + + align:start position:0% +material which will cons which will +concern linear systems of equations will + + align:start position:0% +concern linear systems of equations will + + + align:start position:0% +concern linear systems of equations will +be begin with our next lecture and until + + align:start position:0% +be begin with our next lecture and until + + + align:start position:0% +be begin with our next lecture and until +next time + + align:start position:0% +next time + + + align:start position:0% +next time +goodbye funding for the publication of + + align:start position:0% +goodbye funding for the publication of + + + align:start position:0% +goodbye funding for the publication of +this video was provided by the Gabriella + + align:start position:0% +this video was provided by the Gabriella + + + align:start position:0% +this video was provided by the Gabriella +and Paul rosenbom + + align:start position:0% +and Paul rosenbom + + + align:start position:0% +and Paul rosenbom +foundation help ocw continue to provide + + align:start position:0% +foundation help ocw continue to provide + + + align:start position:0% +foundation help ocw continue to provide +free and open access to MIT courses by + + align:start position:0% +free and open access to MIT courses by + + + align:start position:0% +free and open access to MIT courses by +making a donation at ocw.mit.edu/donate \ No newline at end of file diff --git a/S5HmxtARo8Q.txt b/S5HmxtARo8Q.txt new file mode 100644 index 0000000000000000000000000000000000000000..f45e1984594823dfb50b478b6f09e65b4d5312f1 --- /dev/null +++ b/S5HmxtARo8Q.txt @@ -0,0 +1,4523 @@ +align:start position:0% + +we are excited and honored to have + + align:start position:0% +we are excited and honored to have + + + align:start position:0% +we are excited and honored to have +professor Stephen carpenter with us and + + align:start position:0% +professor Stephen carpenter with us and + + + align:start position:0% +professor Stephen carpenter with us and +this is the first of a series of events + + align:start position:0% +this is the first of a series of events + + + align:start position:0% +this is the first of a series of events +on Larry Susskind on the faculty and + + align:start position:0% +on Larry Susskind on the faculty and + + + align:start position:0% +on Larry Susskind on the faculty and +urban studies and planning it's + + align:start position:0% +urban studies and planning it's + + + align:start position:0% +urban studies and planning it's +interesting to me that several people + + align:start position:0% +interesting to me that several people + + + align:start position:0% +interesting to me that several people +here have a water interest several + + align:start position:0% +here have a water interest several + + + align:start position:0% +here have a water interest several +people here of planning interest several + + align:start position:0% +people here of planning interest several + + + align:start position:0% +people here of planning interest several +people here have artistic or arts + + align:start position:0% +people here have artistic or arts + + + align:start position:0% +people here have artistic or arts +methods interest several people here + + align:start position:0% +methods interest several people here + + + align:start position:0% +methods interest several people here +have sort of public education interest + + align:start position:0% +have sort of public education interest + + + align:start position:0% +have sort of public education interest +and and all of those are alive and well + + align:start position:0% +and and all of those are alive and well + + + align:start position:0% +and and all of those are alive and well +in the department of urban studies and + + align:start position:0% +in the department of urban studies and + + + align:start position:0% +in the department of urban studies and +planning in different kinds of ways + + align:start position:0% +planning in different kinds of ways + + + align:start position:0% +planning in different kinds of ways +there is an environmental group in the + + align:start position:0% +there is an environmental group in the + + + align:start position:0% +there is an environmental group in the +department that I have had some + + align:start position:0% +department that I have had some + + + align:start position:0% +department that I have had some +responsibility for and water is + + align:start position:0% +responsibility for and water is + + + align:start position:0% +responsibility for and water is +concerned within the environmental group + + align:start position:0% +concerned within the environmental group + + + align:start position:0% +concerned within the environmental group +not just domestically but + + align:start position:0% +not just domestically but + + + align:start position:0% +not just domestically but +internationally which relates to part of + + align:start position:0% +internationally which relates to part of + + + align:start position:0% +internationally which relates to part of +your work we're interested in water as + + align:start position:0% +your work we're interested in water as + + + align:start position:0% +your work we're interested in water as +environmental justice concern not just a + + align:start position:0% +environmental justice concern not just a + + + align:start position:0% +environmental justice concern not just a +natural resource management concern and + + align:start position:0% +natural resource management concern and + + + align:start position:0% +natural resource management concern and +so when I first learned of some of the + + align:start position:0% +so when I first learned of some of the + + + align:start position:0% +so when I first learned of some of the +ways in which your work is focused on + + align:start position:0% +ways in which your work is focused on + + + align:start position:0% +ways in which your work is focused on +making clean water available to people + + align:start position:0% +making clean water available to people + + + align:start position:0% +making clean water available to people +in different places there was a direct + + align:start position:0% +in different places there was a direct + + + align:start position:0% +in different places there was a direct +connection with that aspect of of what + + align:start position:0% +connection with that aspect of of what + + + align:start position:0% +connection with that aspect of of what +we do I was really interested in how + + align:start position:0% +we do I was really interested in how + + + align:start position:0% +we do I was really interested in how +issues of race could be raised in a way + + align:start position:0% +issues of race could be raised in a way + + + align:start position:0% +issues of race could be raised in a way +the conversation was possible and that + + align:start position:0% +the conversation was possible and that + + + align:start position:0% +the conversation was possible and that +is another very big part of what our + + align:start position:0% +is another very big part of what our + + + align:start position:0% +is another very big part of what our +department and our school are interested + + align:start position:0% +department and our school are interested + + + align:start position:0% +department and our school are interested +in so by way of background those are + + align:start position:0% +in so by way of background those are + + + align:start position:0% +in so by way of background those are +some of the thematic interests that led + + align:start position:0% +some of the thematic interests that led + + + align:start position:0% +some of the thematic interests that led +us to very much want you to be here well + + align:start position:0% +us to very much want you to be here well + + + align:start position:0% +us to very much want you to be here well +thanks Larry + + align:start position:0% +thanks Larry + + + align:start position:0% +thanks Larry +as far back as I can remember I like + + align:start position:0% +as far back as I can remember I like + + + align:start position:0% +as far back as I can remember I like +making stuff I'll just make things you + + align:start position:0% +making stuff I'll just make things you + + + align:start position:0% +making stuff I'll just make things you +know I'm the oldest of four boys and the + + align:start position:0% +know I'm the oldest of four boys and the + + + align:start position:0% +know I'm the oldest of four boys and the +oldest and the youngest were born five + + align:start position:0% +oldest and the youngest were born five + + + align:start position:0% +oldest and the youngest were born five +and a half years apart no twins so we + + align:start position:0% +and a half years apart no twins so we + + + align:start position:0% +and a half years apart no twins so we +were constantly together in doing things + + align:start position:0% +were constantly together in doing things + + + align:start position:0% +were constantly together in doing things +and we make + + align:start position:0% +and we make + + + align:start position:0% +and we make +like a set of golf clubs my dad had golf + + align:start position:0% +like a set of golf clubs my dad had golf + + + align:start position:0% +like a set of golf clubs my dad had golf +clubs we weren't allowed to use them so + + align:start position:0% +clubs we weren't allowed to use them so + + + align:start position:0% +clubs we weren't allowed to use them so +we made them of course we used his + + align:start position:0% +we made them of course we used his + + + align:start position:0% +we made them of course we used his +copper pipe for the the plumbing in the + + align:start position:0% +copper pipe for the the plumbing in the + + + align:start position:0% +copper pipe for the the plumbing in the +house and so making things was always + + align:start position:0% +house and so making things was always + + + align:start position:0% +house and so making things was always +part of what what I did and and have + + align:start position:0% +part of what what I did and and have + + + align:start position:0% +part of what what I did and and have +done and just engaging the one his + + align:start position:0% +done and just engaging the one his + + + align:start position:0% +done and just engaging the one his +shifts and has moved my backgrounds + + align:start position:0% +shifts and has moved my backgrounds + + + align:start position:0% +shifts and has moved my backgrounds +really pottery his really ceramics + + align:start position:0% +really pottery his really ceramics + + + align:start position:0% +really pottery his really ceramics +touching the clay touching the mud + + align:start position:0% +touching the clay touching the mud + + + align:start position:0% +touching the clay touching the mud +making things that's my degree is in + + align:start position:0% +making things that's my degree is in + + + align:start position:0% +making things that's my degree is in +ceramics and fine art I don't know what + + align:start position:0% +ceramics and fine art I don't know what + + + align:start position:0% +ceramics and fine art I don't know what +it was this urge ability interest for + + align:start position:0% +it was this urge ability interest for + + + align:start position:0% +it was this urge ability interest for +teaching for education so that + + align:start position:0% +teaching for education so that + + + align:start position:0% +teaching for education so that +complicated the situation making stuff + + align:start position:0% +complicated the situation making stuff + + + align:start position:0% +complicated the situation making stuff +and teaching stuff but actually you can + + align:start position:0% +and teaching stuff but actually you can + + + align:start position:0% +and teaching stuff but actually you can +do that that's called being an art + + align:start position:0% +do that that's called being an art + + + align:start position:0% +do that that's called being an art +educator or a teacher and the ceramics + + align:start position:0% +educator or a teacher and the ceramics + + + align:start position:0% +educator or a teacher and the ceramics +piece stayed with I couldn't shake the + + align:start position:0% +piece stayed with I couldn't shake the + + + align:start position:0% +piece stayed with I couldn't shake the +clay couldn't get the clay out of my + + align:start position:0% +clay couldn't get the clay out of my + + + align:start position:0% +clay couldn't get the clay out of my +fingernails the making of things had to + + align:start position:0% +fingernails the making of things had to + + + align:start position:0% +fingernails the making of things had to +always be there and I taught elementary + + align:start position:0% +always be there and I taught elementary + + + align:start position:0% +always be there and I taught elementary +school art that was the art teacher in + + align:start position:0% +school art that was the art teacher in + + + align:start position:0% +school art that was the art teacher in +elementary school and that was among the + + align:start position:0% +elementary school and that was among the + + + align:start position:0% +elementary school and that was among the +most invigorating experiences of my life + + align:start position:0% +most invigorating experiences of my life + + + align:start position:0% +most invigorating experiences of my life +because the students are always about + + align:start position:0% +because the students are always about + + + align:start position:0% +because the students are always about +making something their bodies are always + + align:start position:0% +making something their bodies are always + + + align:start position:0% +making something their bodies are always +moving they're constantly in a state of + + align:start position:0% +moving they're constantly in a state of + + + align:start position:0% +moving they're constantly in a state of +absorbing what they're doing in the + + align:start position:0% +absorbing what they're doing in the + + + align:start position:0% +absorbing what they're doing in the +world and seeing other people doing and + + align:start position:0% +world and seeing other people doing and + + + align:start position:0% +world and seeing other people doing and +moving and checking and so that energy + + align:start position:0% +moving and checking and so that energy + + + align:start position:0% +moving and checking and so that energy +was was quite interesting to me followed + + align:start position:0% +was was quite interesting to me followed + + + align:start position:0% +was was quite interesting to me followed +that experience up with a doctoral + + align:start position:0% +that experience up with a doctoral + + + align:start position:0% +that experience up with a doctoral +degree in art education but the idea was + + align:start position:0% +degree in art education but the idea was + + + align:start position:0% +degree in art education but the idea was +that the making and the teaching and the + + align:start position:0% +that the making and the teaching and the + + + align:start position:0% +that the making and the teaching and the +learning and the asking of questions + + align:start position:0% +learning and the asking of questions + + + align:start position:0% +learning and the asking of questions +through art through the visual imagery + + align:start position:0% +through art through the visual imagery + + + align:start position:0% +through art through the visual imagery +that you're talking about that was what + + align:start position:0% +that you're talking about that was what + + + align:start position:0% +that you're talking about that was what +was so important and you mentioned the + + align:start position:0% +was so important and you mentioned the + + + align:start position:0% +was so important and you mentioned the +notion of access + + align:start position:0% +notion of access + + + align:start position:0% +notion of access +well we didn't have golf clubs we didn't + + align:start position:0% +well we didn't have golf clubs we didn't + + + align:start position:0% +well we didn't have golf clubs we didn't +have access to with like we saw we + + align:start position:0% +have access to with like we saw we + + + align:start position:0% +have access to with like we saw we +didn't have access to so making our own + + align:start position:0% +didn't have access to so making our own + + + align:start position:0% +didn't have access to so making our own +access i'm interested in that as well + + align:start position:0% +access i'm interested in that as well + + + align:start position:0% +access i'm interested in that as well +how does one make one's own access so + + align:start position:0% +how does one make one's own access so + + + align:start position:0% +how does one make one's own access so +moving around to a series of different + + align:start position:0% +moving around to a series of different + + + align:start position:0% +moving around to a series of different +universities as an art educator still + + align:start position:0% +universities as an art educator still + + + align:start position:0% +universities as an art educator still +making part of my graduate both graduate + + align:start position:0% +making part of my graduate both graduate + + + align:start position:0% +making part of my graduate both graduate +degrees was about being in the clay + + align:start position:0% +degrees was about being in the clay + + + align:start position:0% +degrees was about being in the clay +studio as much as it was being in the + + align:start position:0% +studio as much as it was being in the + + + align:start position:0% +studio as much as it was being in the +seminar room and that was really the + + align:start position:0% +seminar room and that was really the + + + align:start position:0% +seminar room and that was really the +focus of my dissertation was in the clay + + align:start position:0% +focus of my dissertation was in the clay + + + align:start position:0% +focus of my dissertation was in the clay +studio we were talking and critiquing + + align:start position:0% +studio we were talking and critiquing + + + align:start position:0% +studio we were talking and critiquing +about color and shape and form and how + + align:start position:0% +about color and shape and form and how + + + align:start position:0% +about color and shape and form and how +the glaze works and on the other side of + + align:start position:0% +the glaze works and on the other side of + + + align:start position:0% +the glaze works and on the other side of +the same part of campus on the other + + align:start position:0% +the same part of campus on the other + + + align:start position:0% +the same part of campus on the other +side of the road in the theory class as + + align:start position:0% +side of the road in the theory class as + + + align:start position:0% +side of the road in the theory class as +an art education we're talking about + + align:start position:0% +an art education we're talking about + + + align:start position:0% +an art education we're talking about +postmodern theory and feminist theory + + align:start position:0% +postmodern theory and feminist theory + + + align:start position:0% +postmodern theory and feminist theory +and film theory and + + align:start position:0% +and film theory and + + + align:start position:0% +and film theory and +interpreting installations and and and + + align:start position:0% +interpreting installations and and and + + + align:start position:0% +interpreting installations and and and +performances and then on the other side + + align:start position:0% +performances and then on the other side + + + align:start position:0% +performances and then on the other side +of the road I'd go to my class the next + + align:start position:0% +of the road I'd go to my class the next + + + align:start position:0% +of the road I'd go to my class the next +day we were again critiquing but we were + + align:start position:0% +day we were again critiquing but we were + + + align:start position:0% +day we were again critiquing but we were +talking about oh I like I like that + + align:start position:0% +talking about oh I like I like that + + + align:start position:0% +talking about oh I like I like that +handle show me how you made the handle + + align:start position:0% +handle show me how you made the handle + + + align:start position:0% +handle show me how you made the handle +this handle works and that one doesn't + + align:start position:0% +this handle works and that one doesn't + + + align:start position:0% +this handle works and that one doesn't +we never defined what works meant but + + align:start position:0% +we never defined what works meant but + + + align:start position:0% +we never defined what works meant but +putting those together the making and + + align:start position:0% +putting those together the making and + + + align:start position:0% +putting those together the making and +that interpreting and thinking and + + align:start position:0% +that interpreting and thinking and + + + align:start position:0% +that interpreting and thinking and +theorizing in both registers doesn't + + align:start position:0% +theorizing in both registers doesn't + + + align:start position:0% +theorizing in both registers doesn't +have to be separated so to think of us + + align:start position:0% +have to be separated so to think of us + + + align:start position:0% +have to be separated so to think of us +even with labels I find kind of curious + + align:start position:0% +even with labels I find kind of curious + + + align:start position:0% +even with labels I find kind of curious +like we have to find a place on campus + + align:start position:0% +like we have to find a place on campus + + + align:start position:0% +like we have to find a place on campus +but the understanding that we can move + + align:start position:0% +but the understanding that we can move + + + align:start position:0% +but the understanding that we can move +in and out of those spaces and we can + + align:start position:0% +in and out of those spaces and we can + + + align:start position:0% +in and out of those spaces and we can +start to shed those those identities the + + align:start position:0% +start to shed those those identities the + + + align:start position:0% +start to shed those those identities the +kind of group that has self-assembled + + align:start position:0% +kind of group that has self-assembled + + + align:start position:0% +kind of group that has self-assembled +today speaks to multiple interests that + + align:start position:0% +today speaks to multiple interests that + + + align:start position:0% +today speaks to multiple interests that +I have and trying to weave it into what + + align:start position:0% +I have and trying to weave it into what + + + align:start position:0% +I have and trying to weave it into what +is an art education how does one learn + + align:start position:0% +is an art education how does one learn + + + align:start position:0% +is an art education how does one learn +through the making of things through the + + align:start position:0% +through the making of things through the + + + align:start position:0% +through the making of things through the +to the display of cultural products + + align:start position:0% +to the display of cultural products + + + align:start position:0% +to the display of cultural products +through cultural production what kind of + + align:start position:0% +through cultural production what kind of + + + align:start position:0% +through cultural production what kind of +questions can we ask not just about what + + align:start position:0% +questions can we ask not just about what + + + align:start position:0% +questions can we ask not just about what +someone else has made but what kind of + + align:start position:0% +someone else has made but what kind of + + + align:start position:0% +someone else has made but what kind of +questions can we ask through them the + + align:start position:0% +questions can we ask through them the + + + align:start position:0% +questions can we ask through them the +act of making itself we can make meaning + + align:start position:0% +act of making itself we can make meaning + + + align:start position:0% +act of making itself we can make meaning +through relationships we can make + + align:start position:0% +through relationships we can make + + + align:start position:0% +through relationships we can make +meaning through conversation we can make + + align:start position:0% +meaning through conversation we can make + + + align:start position:0% +meaning through conversation we can make +meaning through verbal or written + + align:start position:0% +meaning through verbal or written + + + align:start position:0% +meaning through verbal or written +responses so it's the the making of + + align:start position:0% +responses so it's the the making of + + + align:start position:0% +responses so it's the the making of +meaning making of cultural product + + align:start position:0% +meaning making of cultural product + + + align:start position:0% +meaning making of cultural product +making of a difference right so this + + align:start position:0% +making of a difference right so this + + + align:start position:0% +making of a difference right so this +notion of making doesn't have to always + + align:start position:0% +notion of making doesn't have to always + + + align:start position:0% +notion of making doesn't have to always +have this physicality to it from saying + + align:start position:0% +have this physicality to it from saying + + + align:start position:0% +have this physicality to it from saying +all that to say that the clay left my + + align:start position:0% +all that to say that the clay left my + + + align:start position:0% +all that to say that the clay left my +fingernails for a while until move to + + align:start position:0% +fingernails for a while until move to + + + align:start position:0% +fingernails for a while until move to +Texas my wife is an engineer mechanical + + align:start position:0% +Texas my wife is an engineer mechanical + + + align:start position:0% +Texas my wife is an engineer mechanical +engineer material science and it's a + + align:start position:0% +engineer material science and it's a + + + align:start position:0% +engineer material science and it's a +great opportunity for her to move there + + align:start position:0% +great opportunity for her to move there + + + align:start position:0% +great opportunity for her to move there +for me there's no art education there at + + align:start position:0% +for me there's no art education there at + + + align:start position:0% +for me there's no art education there at +all they got my CV and didn't know where + + align:start position:0% +all they got my CV and didn't know where + + + align:start position:0% +all they got my CV and didn't know where +to put me send it all over campus and + + align:start position:0% +to put me send it all over campus and + + + align:start position:0% +to put me send it all over campus and +finally the education folks at all will + + align:start position:0% +finally the education folks at all will + + + align:start position:0% +finally the education folks at all will +take him + + align:start position:0% +take him + + + align:start position:0% +take him +it has education in his degree will take + + align:start position:0% +it has education in his degree will take + + + align:start position:0% +it has education in his degree will take +him telling you all that to say I got to + + align:start position:0% +him telling you all that to say I got to + + + align:start position:0% +him telling you all that to say I got to +Texas and art education had to be I had + + align:start position:0% +Texas and art education had to be I had + + + align:start position:0% +Texas and art education had to be I had +to reinvent it or at least I had to + + align:start position:0% +to reinvent it or at least I had to + + + align:start position:0% +to reinvent it or at least I had to +figure out what I meant by it and how I + + align:start position:0% +figure out what I meant by it and how I + + + align:start position:0% +figure out what I meant by it and how I +fit in if you don't have an art + + align:start position:0% +fit in if you don't have an art + + + align:start position:0% +fit in if you don't have an art +department how do you have art education + + align:start position:0% +department how do you have art education + + + align:start position:0% +department how do you have art education +well you just open the studio in your + + align:start position:0% +well you just open the studio in your + + + align:start position:0% +well you just open the studio in your +garage and have people over on Fridays I + + align:start position:0% +garage and have people over on Fridays I + + + align:start position:0% +garage and have people over on Fridays I +did that or you can engage in the work + + align:start position:0% +did that or you can engage in the work + + + align:start position:0% +did that or you can engage in the work +in the curriculum that fixed set of + + align:start position:0% +in the curriculum that fixed set of + + + align:start position:0% +in the curriculum that fixed set of +notions and premeditated concepts terms + + align:start position:0% +notions and premeditated concepts terms + + + align:start position:0% +notions and premeditated concepts terms +practices skills construct that + + align:start position:0% +practices skills construct that + + + align:start position:0% +practices skills construct that +educational experience my entrance into + + align:start position:0% +educational experience my entrance into + + + align:start position:0% +educational experience my entrance into +a more curriculum instruction space was + + align:start position:0% +a more curriculum instruction space was + + + align:start position:0% +a more curriculum instruction space was +through my background as an artist and + + align:start position:0% +through my background as an artist and + + + align:start position:0% +through my background as an artist and +as an art educator the water filter work + + align:start position:0% +as an art educator the water filter work + + + align:start position:0% +as an art educator the water filter work +that I do and have started to do came + + align:start position:0% +that I do and have started to do came + + + align:start position:0% +that I do and have started to do came +about when I was in Texas I met a guy + + align:start position:0% +about when I was in Texas I met a guy + + + align:start position:0% +about when I was in Texas I met a guy +who is name is Oscar muñoz Oscar is in + + align:start position:0% +who is name is Oscar muñoz Oscar is in + + + align:start position:0% +who is name is Oscar muñoz Oscar is in +charge of the Texas A&M colonias + + align:start position:0% +charge of the Texas A&M colonias + + + align:start position:0% +charge of the Texas A&M colonias +programs all along the border + + align:start position:0% +programs all along the border + + + align:start position:0% +programs all along the border +Texas is 1/3 the width of the United + + align:start position:0% +Texas is 1/3 the width of the United + + + align:start position:0% +Texas is 1/3 the width of the United +States so that distance and then 150 + + align:start position:0% +States so that distance and then 150 + + + align:start position:0% +States so that distance and then 150 +miles up is called the border of Texas + + align:start position:0% +miles up is called the border of Texas + + + align:start position:0% +miles up is called the border of Texas +and in that space they live over half a + + align:start position:0% +and in that space they live over half a + + + align:start position:0% +and in that space they live over half a +million people most of whom don't have + + align:start position:0% +million people most of whom don't have + + + align:start position:0% +million people most of whom don't have +access to clean water in their homes and + + align:start position:0% +access to clean water in their homes and + + + align:start position:0% +access to clean water in their homes and +Oscar talk you know let me know this and + + align:start position:0% +Oscar talk you know let me know this and + + + align:start position:0% +Oscar talk you know let me know this and +he works with communities all across + + align:start position:0% +he works with communities all across + + + align:start position:0% +he works with communities all across +that swath and as an art educator that + + align:start position:0% +that swath and as an art educator that + + + align:start position:0% +that swath and as an art educator that +was interesting to me because I had to + + align:start position:0% +was interesting to me because I had to + + + align:start position:0% +was interesting to me because I had to +learn about a lot of the practices that + + align:start position:0% +learn about a lot of the practices that + + + align:start position:0% +learn about a lot of the practices that +that he's up against and faces telling + + align:start position:0% +that he's up against and faces telling + + + align:start position:0% +that he's up against and faces telling +you all it is to say I'm not that I I + + align:start position:0% +you all it is to say I'm not that I I + + + align:start position:0% +you all it is to say I'm not that I I +planned where this has got where my my + + align:start position:0% +planned where this has got where my my + + + align:start position:0% +planned where this has got where my my +work has gone but it it's always my grad + + align:start position:0% +work has gone but it it's always my grad + + + align:start position:0% +work has gone but it it's always my grad +always moved and shifted to new it's + + align:start position:0% +always moved and shifted to new it's + + + align:start position:0% +always moved and shifted to new it's +almost like water water finds its own + + align:start position:0% +almost like water water finds its own + + + align:start position:0% +almost like water water finds its own +level right water fills the this the the + + align:start position:0% +level right water fills the this the the + + + align:start position:0% +level right water fills the this the the +vessel in which it's poured but I've + + align:start position:0% +vessel in which it's poured but I've + + + align:start position:0% +vessel in which it's poured but I've +never lost the clay I've never lost that + + align:start position:0% +never lost the clay I've never lost that + + + align:start position:0% +never lost the clay I've never lost that +notion of making or the ways that + + align:start position:0% +notion of making or the ways that + + + align:start position:0% +notion of making or the ways that +meanings can be made and understandings + + align:start position:0% +meanings can be made and understandings + + + align:start position:0% +meanings can be made and understandings +can be constructed through engagement + + align:start position:0% +can be constructed through engagement + + + align:start position:0% +can be constructed through engagement +with other people that's what education + + align:start position:0% +with other people that's what education + + + align:start position:0% +with other people that's what education +is it's a social space teaching and + + align:start position:0% +is it's a social space teaching and + + + align:start position:0% +is it's a social space teaching and +learning is a social space aren't + + align:start position:0% +learning is a social space aren't + + + align:start position:0% +learning is a social space aren't +education can take up and take on those + + align:start position:0% +education can take up and take on those + + + align:start position:0% +education can take up and take on those +those tasks as well the title for this + + align:start position:0% +those tasks as well the title for this + + + align:start position:0% +those tasks as well the title for this +visit that people have seen and that you + + align:start position:0% +visit that people have seen and that you + + + align:start position:0% +visit that people have seen and that you +gave us is making something from nothing + + align:start position:0% +gave us is making something from nothing + + + align:start position:0% +gave us is making something from nothing +and first of all sort of there's + + align:start position:0% +and first of all sort of there's + + + align:start position:0% +and first of all sort of there's +immediately doubt about whether you can + + align:start position:0% +immediately doubt about whether you can + + + align:start position:0% +immediately doubt about whether you can +actually make I mean you can transform + + align:start position:0% +actually make I mean you can transform + + + align:start position:0% +actually make I mean you can transform +things but the notion that you can make + + align:start position:0% +things but the notion that you can make + + + align:start position:0% +things but the notion that you can make +something out of nothing would sort of + + align:start position:0% +something out of nothing would sort of + + + align:start position:0% +something out of nothing would sort of +defy most of the laws of physics + + align:start position:0% +defy most of the laws of physics + + + align:start position:0% +defy most of the laws of physics +presumably and so you mean something by + + align:start position:0% +presumably and so you mean something by + + + align:start position:0% +presumably and so you mean something by +that and then appropriate technology as + + align:start position:0% +that and then appropriate technology as + + + align:start position:0% +that and then appropriate technology as +intentionally disruptive + + align:start position:0% +intentionally disruptive + + + align:start position:0% +intentionally disruptive +responsibilities + + align:start position:0% +responsibilities + + + align:start position:0% +responsibilities +yeah that is a mouthful that title isn't + + align:start position:0% +yeah that is a mouthful that title isn't + + + align:start position:0% +yeah that is a mouthful that title isn't +I actually had a lot of trouble with it + + align:start position:0% +I actually had a lot of trouble with it + + + align:start position:0% +I actually had a lot of trouble with it +[Laughter] + + align:start position:0% +[Laughter] + + + align:start position:0% +[Laughter] +to the left of the colon making + + align:start position:0% +to the left of the colon making + + + align:start position:0% +to the left of the colon making +something from nothing + + align:start position:0% +something from nothing + + + align:start position:0% +something from nothing +that piece was intentionally provocative + + align:start position:0% +that piece was intentionally provocative + + + align:start position:0% +that piece was intentionally provocative +right I mean you kind of have to do that + + align:start position:0% +right I mean you kind of have to do that + + + align:start position:0% +right I mean you kind of have to do that +in some ways to entice folks to show up + + align:start position:0% +in some ways to entice folks to show up + + + align:start position:0% +in some ways to entice folks to show up +to certain things maybe but the idea of + + align:start position:0% +to certain things maybe but the idea of + + + align:start position:0% +to certain things maybe but the idea of +making of course you know defying laws + + align:start position:0% +making of course you know defying laws + + + align:start position:0% +making of course you know defying laws +of physics yeah I'm with you so no you + + align:start position:0% +of physics yeah I'm with you so no you + + + align:start position:0% +of physics yeah I'm with you so no you +know knowing that there's a problem with + + align:start position:0% +know knowing that there's a problem with + + + align:start position:0% +know knowing that there's a problem with +with that if we think of it in certain + + align:start position:0% +with that if we think of it in certain + + + align:start position:0% +with that if we think of it in certain +realms the idea that there are some + + align:start position:0% +realms the idea that there are some + + + align:start position:0% +realms the idea that there are some +folks who don't necessarily have access + + align:start position:0% +folks who don't necessarily have access + + + align:start position:0% +folks who don't necessarily have access +it's about access maybe it should have + + align:start position:0% +it's about access maybe it should have + + + align:start position:0% +it's about access maybe it should have +said you know making something from + + align:start position:0% +said you know making something from + + + align:start position:0% +said you know making something from +whatever it is that you have right but + + align:start position:0% +whatever it is that you have right but + + + align:start position:0% +whatever it is that you have right but +if we move it to nothing you start to + + align:start position:0% +if we move it to nothing you start to + + + align:start position:0% +if we move it to nothing you start to +think well there's a there's a there's a + + align:start position:0% +think well there's a there's a there's a + + + align:start position:0% +think well there's a there's a there's a +complete and utter lack of something + + align:start position:0% +complete and utter lack of something + + + align:start position:0% +complete and utter lack of something +for example there's some people who have + + align:start position:0% +for example there's some people who have + + + align:start position:0% +for example there's some people who have +no access to clean water we can raise a + + align:start position:0% +no access to clean water we can raise a + + + align:start position:0% +no access to clean water we can raise a +bit of hyperbole there and say they + + align:start position:0% +bit of hyperbole there and say they + + + align:start position:0% +bit of hyperbole there and say they +don't have access or they have nothing + + align:start position:0% +don't have access or they have nothing + + + align:start position:0% +don't have access or they have nothing +there folks you know who we talk about + + align:start position:0% +there folks you know who we talk about + + + align:start position:0% +there folks you know who we talk about +food scarcity we talk about folks who + + align:start position:0% +food scarcity we talk about folks who + + + align:start position:0% +food scarcity we talk about folks who +homeless folks who need shelter I mean + + align:start position:0% +homeless folks who need shelter I mean + + + align:start position:0% +homeless folks who need shelter I mean +so you can take minimum and exaggerate + + align:start position:0% +so you can take minimum and exaggerate + + + align:start position:0% +so you can take minimum and exaggerate +it just a little bit more right it was + + align:start position:0% +it just a little bit more right it was + + + align:start position:0% +it just a little bit more right it was +something called artistic license let's + + align:start position:0% +something called artistic license let's + + + align:start position:0% +something called artistic license let's +let's use that and turn it into nothing + + align:start position:0% +let's use that and turn it into nothing + + + align:start position:0% +let's use that and turn it into nothing +so making something from nothing what + + align:start position:0% +so making something from nothing what + + + align:start position:0% +so making something from nothing what +can we make from what is available to us + + align:start position:0% +can we make from what is available to us + + + align:start position:0% +can we make from what is available to us +so that's the something from nothing and + + align:start position:0% +so that's the something from nothing and + + + align:start position:0% +so that's the something from nothing and +in in the case of this first visit but + + align:start position:0% +in in the case of this first visit but + + + align:start position:0% +in in the case of this first visit but +something is adequate access to clean + + align:start position:0% +something is adequate access to clean + + + align:start position:0% +something is adequate access to clean +water and then nothing is the lack of + + align:start position:0% +water and then nothing is the lack of + + + align:start position:0% +water and then nothing is the lack of +that and the something is a response + + align:start position:0% +that and the something is a response + + + align:start position:0% +that and the something is a response +which would in this case is a ceramic + + align:start position:0% +which would in this case is a ceramic + + + align:start position:0% +which would in this case is a ceramic +water filter made out of clay and + + align:start position:0% +water filter made out of clay and + + + align:start position:0% +water filter made out of clay and +sawdust the nothing is well that's just + + align:start position:0% +sawdust the nothing is well that's just + + + align:start position:0% +sawdust the nothing is well that's just +clay it's it's just in the riverbed + + align:start position:0% +clay it's it's just in the riverbed + + + align:start position:0% +clay it's it's just in the riverbed +that's that's nothing or let's just + + align:start position:0% +that's that's nothing or let's just + + + align:start position:0% +that's that's nothing or let's just +sawdust that's leftover scraps then + + align:start position:0% +sawdust that's leftover scraps then + + + align:start position:0% +sawdust that's leftover scraps then +that's nothing right you see you + + align:start position:0% +that's nothing right you see you + + + align:start position:0% +that's nothing right you see you +understand that play that's going there + + align:start position:0% +understand that play that's going there + + + align:start position:0% +understand that play that's going there +appropriate technology is essentially + + align:start position:0% +appropriate technology is essentially + + + align:start position:0% +appropriate technology is essentially +whatever is available culturally and + + align:start position:0% +whatever is available culturally and + + + align:start position:0% +whatever is available culturally and +locally that fits in with this within + + align:start position:0% +locally that fits in with this within + + + align:start position:0% +locally that fits in with this within +the cultural practices of of a community + + align:start position:0% +the cultural practices of of a community + + + align:start position:0% +the cultural practices of of a community +introducing an external or an unfamiliar + + align:start position:0% +introducing an external or an unfamiliar + + + align:start position:0% +introducing an external or an unfamiliar +substance or chemical or food is not + + align:start position:0% +substance or chemical or food is not + + + align:start position:0% +substance or chemical or food is not +appropriate to certain community because + + align:start position:0% +appropriate to certain community because + + + align:start position:0% +appropriate to certain community because +it's either against one's religion it's + + align:start position:0% +it's either against one's religion it's + + + align:start position:0% +it's either against one's religion it's +against one's history against one's + + align:start position:0% +against one's history against one's + + + align:start position:0% +against one's history against one's +culture it + + align:start position:0% +culture it + + + align:start position:0% +culture it +doesn't fit in so finding something + + align:start position:0% +doesn't fit in so finding something + + + align:start position:0% +doesn't fit in so finding something +that's appropriate for example clay is + + align:start position:0% +that's appropriate for example clay is + + + align:start position:0% +that's appropriate for example clay is +essentially a material that is + + align:start position:0% +essentially a material that is + + + align:start position:0% +essentially a material that is +accessible to almost every single + + align:start position:0% +accessible to almost every single + + + align:start position:0% +accessible to almost every single +culture in the history of this of the + + align:start position:0% +culture in the history of this of the + + + align:start position:0% +culture in the history of this of the +world and clay is a natural naturally + + align:start position:0% +world and clay is a natural naturally + + + align:start position:0% +world and clay is a natural naturally +occurring material in most places around + + align:start position:0% +occurring material in most places around + + + align:start position:0% +occurring material in most places around +the world in some places using plastic + + align:start position:0% +the world in some places using plastic + + + align:start position:0% +the world in some places using plastic +oh that doesn't seem to make sense or + + align:start position:0% +oh that doesn't seem to make sense or + + + align:start position:0% +oh that doesn't seem to make sense or +appropriate technology is using what is + + align:start position:0% +appropriate technology is using what is + + + align:start position:0% +appropriate technology is using what is +that hand philosopher theorist Umberto + + align:start position:0% +that hand philosopher theorist Umberto + + + align:start position:0% +that hand philosopher theorist Umberto +Eco he was a guy who knew everything but + + align:start position:0% +Eco he was a guy who knew everything but + + + align:start position:0% +Eco he was a guy who knew everything but +he didn't know it echo had numerous + + align:start position:0% +he didn't know it echo had numerous + + + align:start position:0% +he didn't know it echo had numerous +theories among them where these in + + align:start position:0% +theories among them where these in + + + align:start position:0% +theories among them where these in +theory of intentions he says that the + + align:start position:0% +theory of intentions he says that the + + + align:start position:0% +theory of intentions he says that the +artist or the author has an intention + + align:start position:0% +artist or the author has an intention + + + align:start position:0% +artist or the author has an intention +and the viewer or the reader has an + + align:start position:0% +and the viewer or the reader has an + + + align:start position:0% +and the viewer or the reader has an +intention but he also says the work has + + align:start position:0% +intention but he also says the work has + + + align:start position:0% +intention but he also says the work has +an intention that comes about through + + align:start position:0% +an intention that comes about through + + + align:start position:0% +an intention that comes about through +the rest process or a series of events + + align:start position:0% +the rest process or a series of events + + + align:start position:0% +the rest process or a series of events +but this idea of having an intention + + align:start position:0% +but this idea of having an intention + + + align:start position:0% +but this idea of having an intention +means it's deliberate so I'm interested + + align:start position:0% +means it's deliberate so I'm interested + + + align:start position:0% +means it's deliberate so I'm interested +in in in thinking about why we're doing + + align:start position:0% +in in in thinking about why we're doing + + + align:start position:0% +in in in thinking about why we're doing +what we're doing that's that's where + + align:start position:0% +what we're doing that's that's where + + + align:start position:0% +what we're doing that's that's where +that intentional piece disruptive you + + align:start position:0% +that intentional piece disruptive you + + + align:start position:0% +that intentional piece disruptive you +know if I pick this up and I threw this + + align:start position:0% +know if I pick this up and I threw this + + + align:start position:0% +know if I pick this up and I threw this +water at the camera that would be + + align:start position:0% +water at the camera that would be + + + align:start position:0% +water at the camera that would be +disruptive in a number of rays or if + + align:start position:0% +disruptive in a number of rays or if + + + align:start position:0% +disruptive in a number of rays or if +you're in a you know in a quiet library + + align:start position:0% +you're in a you know in a quiet library + + + align:start position:0% +you're in a you know in a quiet library +and a stampede of aardvarks comes + + align:start position:0% +and a stampede of aardvarks comes + + + align:start position:0% +and a stampede of aardvarks comes +through the space that's disruption + + align:start position:0% +through the space that's disruption + + + align:start position:0% +through the space that's disruption +right so we understand disruption is + + align:start position:0% +right so we understand disruption is + + + align:start position:0% +right so we understand disruption is +something that is abnormal or not + + align:start position:0% +something that is abnormal or not + + + align:start position:0% +something that is abnormal or not +expected within a particular context + + align:start position:0% +expected within a particular context + + + align:start position:0% +expected within a particular context +that has assumed rules regulations and + + align:start position:0% +that has assumed rules regulations and + + + align:start position:0% +that has assumed rules regulations and +ways of being but I'm also thinking of a + + align:start position:0% +ways of being but I'm also thinking of a + + + align:start position:0% +ways of being but I'm also thinking of a +disruption in the intentional sense of + + align:start position:0% +disruption in the intentional sense of + + + align:start position:0% +disruption in the intentional sense of +to reveal or to poke at or to engage or + + align:start position:0% +to reveal or to poke at or to engage or + + + align:start position:0% +to reveal or to poke at or to engage or +to entice a certain kind of conversation + + align:start position:0% +to entice a certain kind of conversation + + + align:start position:0% +to entice a certain kind of conversation +or relationship and that kind of + + align:start position:0% +or relationship and that kind of + + + align:start position:0% +or relationship and that kind of +conversation relationship is the + + align:start position:0% +conversation relationship is the + + + align:start position:0% +conversation relationship is the +responsibility would you agree that most + + align:start position:0% +responsibility would you agree that most + + + align:start position:0% +responsibility would you agree that most +educational efforts are disruptions + + align:start position:0% +educational efforts are disruptions + + + align:start position:0% +educational efforts are disruptions +aimed at fulfilling a responsibility + + align:start position:0% +aimed at fulfilling a responsibility + + + align:start position:0% +aimed at fulfilling a responsibility +that is defining education that way I + + align:start position:0% +that is defining education that way I + + + align:start position:0% +that is defining education that way I +don't think enough of them are oh you + + align:start position:0% +don't think enough of them are oh you + + + align:start position:0% +don't think enough of them are oh you +think they should be I think they should + + align:start position:0% +think they should be I think they should + + + align:start position:0% +think they should be I think they should +I like to shift that up and question + + align:start position:0% +I like to shift that up and question + + + align:start position:0% +I like to shift that up and question +that and then there's there's it's it's + + align:start position:0% +that and then there's there's it's it's + + + align:start position:0% +that and then there's there's it's it's +very difficult to to get at new ways of + + align:start position:0% +very difficult to to get at new ways of + + + align:start position:0% +very difficult to to get at new ways of +doing something without disrupting a + + align:start position:0% +doing something without disrupting a + + + align:start position:0% +doing something without disrupting a +status quo without without questioning + + align:start position:0% +status quo without without questioning + + + align:start position:0% +status quo without without questioning +it we say it's because we're responsible + + align:start position:0% +it we say it's because we're responsible + + + align:start position:0% +it we say it's because we're responsible +and we have to disrupt but what about + + align:start position:0% +and we have to disrupt but what about + + + align:start position:0% +and we have to disrupt but what about +the choice of the people and the place + + align:start position:0% +the choice of the people and the place + + + align:start position:0% +the choice of the people and the place +whose lives you're disrupting is that + + align:start position:0% +whose lives you're disrupting is that + + + align:start position:0% +whose lives you're disrupting is that +fair to them sure yeah no certainly the + + align:start position:0% +fair to them sure yeah no certainly the + + + align:start position:0% +fair to them sure yeah no certainly the +way you frame it it's not fair to them + + align:start position:0% +way you frame it it's not fair to them + + + align:start position:0% +way you frame it it's not fair to them +but in the disruption of the lives of + + align:start position:0% +but in the disruption of the lives of + + + align:start position:0% +but in the disruption of the lives of +the communities that are mentioned in + + align:start position:0% +the communities that are mentioned in + + + align:start position:0% +the communities that are mentioned in +Texas it's not disrupting uninvited + + align:start position:0% +Texas it's not disrupting uninvited + + + align:start position:0% +Texas it's not disrupting uninvited +it's an invited disruption and second + + align:start position:0% +it's an invited disruption and second + + + align:start position:0% +it's an invited disruption and second +the disruption has to do with whatever + + align:start position:0% +the disruption has to do with whatever + + + align:start position:0% +the disruption has to do with whatever +the current practice was new was not + + align:start position:0% +the current practice was new was not + + + align:start position:0% +the current practice was new was not +fulfilling or were responding to needs + + align:start position:0% +fulfilling or were responding to needs + + + align:start position:0% +fulfilling or were responding to needs +of the community in in their eyes and in + + align:start position:0% +of the community in in their eyes and in + + + align:start position:0% +of the community in in their eyes and in +you know to my eyes as well so my friend + + align:start position:0% +you know to my eyes as well so my friend + + + align:start position:0% +you know to my eyes as well so my friend +as I mentioned Oscar who for years has + + align:start position:0% +as I mentioned Oscar who for years has + + + align:start position:0% +as I mentioned Oscar who for years has +been working in throughout South Texas + + align:start position:0% +been working in throughout South Texas + + + align:start position:0% +been working in throughout South Texas +when he learned to the work I was that I + + align:start position:0% +when he learned to the work I was that I + + + align:start position:0% +when he learned to the work I was that I +was you know at that point still + + align:start position:0% +was you know at that point still + + + align:start position:0% +was you know at that point still +learning how to do he said oh there's + + align:start position:0% +learning how to do he said oh there's + + + align:start position:0% +learning how to do he said oh there's +there's a water issue would you come + + align:start position:0% +there's a water issue would you come + + + align:start position:0% +there's a water issue would you come +down and work with us we talked to us + + align:start position:0% +down and work with us we talked to us + + + align:start position:0% +down and work with us we talked to us +let's see if this would work out that + + align:start position:0% +let's see if this would work out that + + + align:start position:0% +let's see if this would work out that +was my invitation to come in Oscar was + + align:start position:0% +was my invitation to come in Oscar was + + + align:start position:0% +was my invitation to come in Oscar was +already part of that community I would + + align:start position:0% +already part of that community I would + + + align:start position:0% +already part of that community I would +never imagine just driving down there + + align:start position:0% +never imagine just driving down there + + + align:start position:0% +never imagine just driving down there +driving to any community and say hey + + align:start position:0% +driving to any community and say hey + + + align:start position:0% +driving to any community and say hey +Dyke if something you need I'm gonna + + align:start position:0% +Dyke if something you need I'm gonna + + + align:start position:0% +Dyke if something you need I'm gonna +sell you something that's not my + + align:start position:0% +sell you something that's not my + + + align:start position:0% +sell you something that's not my +approach and so that kind of disruption + + align:start position:0% +approach and so that kind of disruption + + + align:start position:0% +approach and so that kind of disruption +I think is on the the unethical side he + + align:start position:0% +I think is on the the unethical side he + + + align:start position:0% +I think is on the the unethical side he +was a bit wary of someone coming in and + + align:start position:0% +was a bit wary of someone coming in and + + + align:start position:0% +was a bit wary of someone coming in and +he's shared and other people have shared + + align:start position:0% +he's shared and other people have shared + + + align:start position:0% +he's shared and other people have shared +stories with me of researchers going + + align:start position:0% +stories with me of researchers going + + + align:start position:0% +stories with me of researchers going +into communities oh yeah I have this + + align:start position:0% +into communities oh yeah I have this + + + align:start position:0% +into communities oh yeah I have this +ideas let me study what you're doing let + + align:start position:0% +ideas let me study what you're doing let + + + align:start position:0% +ideas let me study what you're doing let +me work with you and they take the + + align:start position:0% +me work with you and they take the + + + align:start position:0% +me work with you and they take the +information and there's a report that's + + align:start position:0% +information and there's a report that's + + + align:start position:0% +information and there's a report that's +promised and the report never gets back + + align:start position:0% +promised and the report never gets back + + + align:start position:0% +promised and the report never gets back +to the communities or the results never + + align:start position:0% +to the communities or the results never + + + align:start position:0% +to the communities or the results never +never help and he said he has never he + + align:start position:0% +never help and he said he has never he + + + align:start position:0% +never help and he said he has never he +had never seen a report come back based + + align:start position:0% +had never seen a report come back based + + + align:start position:0% +had never seen a report come back based +on the invitations to the scholars and + + align:start position:0% +on the invitations to the scholars and + + + align:start position:0% +on the invitations to the scholars and +so once we got to know each other he + + align:start position:0% +so once we got to know each other he + + + align:start position:0% +so once we got to know each other he +felt comfortable with me so but then he + + align:start position:0% +felt comfortable with me so but then he + + + align:start position:0% +felt comfortable with me so but then he +had to go through a process of talking + + align:start position:0% +had to go through a process of talking + + + align:start position:0% +had to go through a process of talking +with members of the community to say hey + + align:start position:0% +with members of the community to say hey + + + align:start position:0% +with members of the community to say hey +here's you know have this friend coming + + align:start position:0% +here's you know have this friend coming + + + align:start position:0% +here's you know have this friend coming +down that's the invitation is the + + align:start position:0% +down that's the invitation is the + + + align:start position:0% +down that's the invitation is the +invitation pieces so what is an + + align:start position:0% +invitation pieces so what is an + + + align:start position:0% +invitation pieces so what is an +invitation have to consist of for you to + + align:start position:0% +invitation have to consist of for you to + + + align:start position:0% +invitation have to consist of for you to +be of a sort that you're comfortable + + align:start position:0% +be of a sort that you're comfortable + + + align:start position:0% +be of a sort that you're comfortable +then responding in this rich disruptive + + align:start position:0% +then responding in this rich disruptive + + + align:start position:0% +then responding in this rich disruptive +way you need a vote of the community has + + align:start position:0% +way you need a vote of the community has + + + align:start position:0% +way you need a vote of the community has +to be 100 percent majority rule people + + align:start position:0% +to be 100 percent majority rule people + + + align:start position:0% +to be 100 percent majority rule people +you like say come on down + + align:start position:0% +you like say come on down + + + align:start position:0% +you like say come on down +what what is in your mind about what + + align:start position:0% +what what is in your mind about what + + + align:start position:0% +what what is in your mind about what +legitimizes these kinds of disruptions + + align:start position:0% +legitimizes these kinds of disruptions + + + align:start position:0% +legitimizes these kinds of disruptions +again it has to be that imitation from + + align:start position:0% +again it has to be that imitation from + + + align:start position:0% +again it has to be that imitation from +someone who is positioned within the + + align:start position:0% +someone who is positioned within the + + + align:start position:0% +someone who is positioned within the +community then there has to be for me a + + align:start position:0% +community then there has to be for me a + + + align:start position:0% +community then there has to be for me a +conversation and and so no the entire + + align:start position:0% +conversation and and so no the entire + + + align:start position:0% +conversation and and so no the entire +community because defining who is in the + + align:start position:0% +community because defining who is in the + + + align:start position:0% +community because defining who is in the +community is often difficult to do + + align:start position:0% +community is often difficult to do + + + align:start position:0% +community is often difficult to do +anyway + + align:start position:0% +anyway + + + align:start position:0% +anyway +certainly it's it's often just a leader + + align:start position:0% +certainly it's it's often just a leader + + + align:start position:0% +certainly it's it's often just a leader +or some member of the community who + + align:start position:0% +or some member of the community who + + + align:start position:0% +or some member of the community who +might want to engage a conversation that + + align:start position:0% +might want to engage a conversation that + + + align:start position:0% +might want to engage a conversation that +that then might expand in their own + + align:start position:0% +that then might expand in their own + + + align:start position:0% +that then might expand in their own +circles in this particular case in Texas + + align:start position:0% +circles in this particular case in Texas + + + align:start position:0% +circles in this particular case in Texas +through my colleague we met with a few + + align:start position:0% +through my colleague we met with a few + + + align:start position:0% +through my colleague we met with a few +leaders people who had worked within the + + align:start position:0% +leaders people who had worked within the + + + align:start position:0% +leaders people who had worked within the +communities as promotoras as community + + align:start position:0% +communities as promotoras as community + + + align:start position:0% +communities as promotoras as community +educators and and other senior members + + align:start position:0% +educators and and other senior members + + + align:start position:0% +educators and and other senior members +of the community + + align:start position:0% +of the community + + + align:start position:0% +of the community +a senior meeting they had been doing + + align:start position:0% +a senior meeting they had been doing + + + align:start position:0% +a senior meeting they had been doing +work at the community centers and it was + + align:start position:0% +work at the community centers and it was + + + align:start position:0% +work at the community centers and it was +let's just talk let's see where the + + align:start position:0% +let's just talk let's see where the + + + align:start position:0% +let's just talk let's see where the +conversation goes very much like what + + align:start position:0% +conversation goes very much like what + + + align:start position:0% +conversation goes very much like what +we're doing here having having a + + align:start position:0% +we're doing here having having a + + + align:start position:0% +we're doing here having having a +conversation now it's not my role or + + align:start position:0% +conversation now it's not my role or + + + align:start position:0% +conversation now it's not my role or +position or personality or interest to + + align:start position:0% +position or personality or interest to + + + align:start position:0% +position or personality or interest to +push that after that conversation that's + + align:start position:0% +push that after that conversation that's + + + align:start position:0% +push that after that conversation that's +on that's on whomever to to take that up + + align:start position:0% +on that's on whomever to to take that up + + + align:start position:0% +on that's on whomever to to take that up +so when I speak of community it's it's + + align:start position:0% +so when I speak of community it's it's + + + align:start position:0% +so when I speak of community it's it's +it's not the entirety there's not a + + align:start position:0% +it's not the entirety there's not a + + + align:start position:0% +it's not the entirety there's not a +simple answer in this we all struggle + + align:start position:0% +simple answer in this we all struggle + + + align:start position:0% +simple answer in this we all struggle +with this notion of the artist as the + + align:start position:0% +with this notion of the artist as the + + + align:start position:0% +with this notion of the artist as the +independent thinker as a creator of + + align:start position:0% +independent thinker as a creator of + + + align:start position:0% +independent thinker as a creator of +something that's an expression of an + + align:start position:0% +something that's an expression of an + + + align:start position:0% +something that's an expression of an +individual view when you're calling this + + align:start position:0% +individual view when you're calling this + + + align:start position:0% +individual view when you're calling this +a form of art education but isn't it + + align:start position:0% +a form of art education but isn't it + + + align:start position:0% +a form of art education but isn't it +contrary to artists being artists how + + align:start position:0% +contrary to artists being artists how + + + align:start position:0% +contrary to artists being artists how +was it art yeah so that's not a small + + align:start position:0% +was it art yeah so that's not a small + + + align:start position:0% +was it art yeah so that's not a small +question but it's a very important + + align:start position:0% +question but it's a very important + + + align:start position:0% +question but it's a very important +question it's a central question that + + align:start position:0% +question it's a central question that + + + align:start position:0% +question it's a central question that +I'm still answering for myself but there + + align:start position:0% +I'm still answering for myself but there + + + align:start position:0% +I'm still answering for myself but there +are three realms here one is the work in + + align:start position:0% +are three realms here one is the work in + + + align:start position:0% +are three realms here one is the work in +South Texas that I actually wouldn't + + align:start position:0% +South Texas that I actually wouldn't + + + align:start position:0% +South Texas that I actually wouldn't +call that art or art education okay + + align:start position:0% +call that art or art education okay + + + align:start position:0% +call that art or art education okay +second is the kind of work that I will + + align:start position:0% +second is the kind of work that I will + + + align:start position:0% +second is the kind of work that I will +do tomorrow the performance and that + + align:start position:0% +do tomorrow the performance and that + + + align:start position:0% +do tomorrow the performance and that +moves into the realm of the social + + align:start position:0% +moves into the realm of the social + + + align:start position:0% +moves into the realm of the social +practice and that's where I've I've come + + align:start position:0% +practice and that's where I've I've come + + + align:start position:0% +practice and that's where I've I've come +to an agreement understanding + + align:start position:0% +to an agreement understanding + + + align:start position:0% +to an agreement understanding +comfortable place with myself that + + align:start position:0% +comfortable place with myself that + + + align:start position:0% +comfortable place with myself that +that's where the art education happened + + align:start position:0% +that's where the art education happened + + + align:start position:0% +that's where the art education happened +and then this there's a third piece your + + align:start position:0% +and then this there's a third piece your + + + align:start position:0% +and then this there's a third piece your +definition of an artist and what an + + align:start position:0% +definition of an artist and what an + + + align:start position:0% +definition of an artist and what an +artist does that I want to disrupt down + + align:start position:0% +artist does that I want to disrupt down + + + align:start position:0% +artist does that I want to disrupt down +in South Texas that kind of work for me + + align:start position:0% +in South Texas that kind of work for me + + + align:start position:0% +in South Texas that kind of work for me +is not art education it certainly uses + + align:start position:0% +is not art education it certainly uses + + + align:start position:0% +is not art education it certainly uses +an employ certain artistic practices + + align:start position:0% +an employ certain artistic practices + + + align:start position:0% +an employ certain artistic practices +folks who have access to a kiln know how + + align:start position:0% +folks who have access to a kiln know how + + + align:start position:0% +folks who have access to a kiln know how +to fire kiln and have access to clay + + align:start position:0% +to fire kiln and have access to clay + + + align:start position:0% +to fire kiln and have access to clay +that's where you want to begin your work + + align:start position:0% +that's where you want to begin your work + + + align:start position:0% +that's where you want to begin your work +usually that's the the tile person or + + align:start position:0% +usually that's the the tile person or + + + align:start position:0% +usually that's the the tile person or +the the pot putter or it's the brick + + align:start position:0% +the the pot putter or it's the brick + + + align:start position:0% +the the pot putter or it's the brick +maker but my collaboration and myung + + align:start position:0% +maker but my collaboration and myung + + + align:start position:0% +maker but my collaboration and myung +involvement in that project I wouldn't + + align:start position:0% +involvement in that project I wouldn't + + + align:start position:0% +involvement in that project I wouldn't +call that art that was kind of me shed + + align:start position:0% +call that art that was kind of me shed + + + align:start position:0% +call that art that was kind of me shed +you know that that helps to clarify that + + align:start position:0% +you know that that helps to clarify that + + + align:start position:0% +you know that that helps to clarify that +piece of it so the work that I'm going + + align:start position:0% +piece of it so the work that I'm going + + + align:start position:0% +piece of it so the work that I'm going +to do I will do tomorrow I'm gonna set + + align:start position:0% +to do I will do tomorrow I'm gonna set + + + align:start position:0% +to do I will do tomorrow I'm gonna set +up a water filter production facility in + + align:start position:0% +up a water filter production facility in + + + align:start position:0% +up a water filter production facility in +one of the rooms downstairs and I'm + + align:start position:0% +one of the rooms downstairs and I'm + + + align:start position:0% +one of the rooms downstairs and I'm +gonna make water filters the idea there + + align:start position:0% +gonna make water filters the idea there + + + align:start position:0% +gonna make water filters the idea there +is to engage in a practice that somehow + + align:start position:0% +is to engage in a practice that somehow + + + align:start position:0% +is to engage in a practice that somehow +blurs what might be our conventional + + align:start position:0% +blurs what might be our conventional + + + align:start position:0% +blurs what might be our conventional +notions of art making art practice with + + align:start position:0% +notions of art making art practice with + + + align:start position:0% +notions of art making art practice with +practices from other disciplines we're + + align:start position:0% +practices from other disciplines we're + + + align:start position:0% +practices from other disciplines we're +not quite sure where one ends and one + + align:start position:0% +not quite sure where one ends and one + + + align:start position:0% +not quite sure where one ends and one +begins and it's supposed to remain in + + align:start position:0% +begins and it's supposed to remain in + + + align:start position:0% +begins and it's supposed to remain in +that uncomfortable space if one is + + align:start position:0% +that uncomfortable space if one is + + + align:start position:0% +that uncomfortable space if one is +thinking in that social practice art as + + align:start position:0% +thinking in that social practice art as + + + align:start position:0% +thinking in that social practice art as +social practice register if you can set + + align:start position:0% +social practice register if you can set + + + align:start position:0% +social practice register if you can set +up that practice as an engagement as an + + align:start position:0% +up that practice as an engagement as an + + + align:start position:0% +up that practice as an engagement as an +ongoing set of activities where people + + align:start position:0% +ongoing set of activities where people + + + align:start position:0% +ongoing set of activities where people +can come in and out of that space + + align:start position:0% +can come in and out of that space + + + align:start position:0% +can come in and out of that space +there's an educational component + + align:start position:0% +there's an educational component + + + align:start position:0% +there's an educational component +invariably there'll be a question hey + + align:start position:0% +invariably there'll be a question hey + + + align:start position:0% +invariably there'll be a question hey +man what are you doing that's an + + align:start position:0% +man what are you doing that's an + + + align:start position:0% +man what are you doing that's an +invitation right there for me to respond + + align:start position:0% +invitation right there for me to respond + + + align:start position:0% +invitation right there for me to respond +so we can establish this conversation as + + align:start position:0% +so we can establish this conversation as + + + align:start position:0% +so we can establish this conversation as +a relationship you're not creating art + + align:start position:0% +a relationship you're not creating art + + + align:start position:0% +a relationship you're not creating art +you're creating something that serves a + + align:start position:0% +you're creating something that serves a + + + align:start position:0% +you're creating something that serves a +function in response to the need of a + + align:start position:0% +function in response to the need of a + + + align:start position:0% +function in response to the need of a +client you're saying though it's not art + + align:start position:0% +client you're saying though it's not art + + + align:start position:0% +client you're saying though it's not art +I'm an artist and it's my social + + align:start position:0% +I'm an artist and it's my social + + + align:start position:0% +I'm an artist and it's my social +practice that you should observe here is + + align:start position:0% +practice that you should observe here is + + + align:start position:0% +practice that you should observe here is +art education but the product of my + + align:start position:0% +art education but the product of my + + + align:start position:0% +art education but the product of my +artwork is not art it's more than the + + align:start position:0% +artwork is not art it's more than the + + + align:start position:0% +artwork is not art it's more than the +filter itself that filter is just one + + align:start position:0% +filter itself that filter is just one + + + align:start position:0% +filter itself that filter is just one +component of the work the work being the + + align:start position:0% +component of the work the work being the + + + align:start position:0% +component of the work the work being the +performance education as experience this + + align:start position:0% +performance education as experience this + + + align:start position:0% +performance education as experience this +notion of experience is where the + + align:start position:0% +notion of experience is where the + + + align:start position:0% +notion of experience is where the +education happens for some of us the + + align:start position:0% +education happens for some of us the + + + align:start position:0% +education happens for some of us the +next step is oh and I want to help a + + align:start position:0% +next step is oh and I want to help a + + + align:start position:0% +next step is oh and I want to help a +place in Africa or Latin America in a + + align:start position:0% +place in Africa or Latin America in a + + + align:start position:0% +place in Africa or Latin America in a +community make a factory + + align:start position:0% +community make a factory + + + align:start position:0% +community make a factory +where there are people now without me + + align:start position:0% +where there are people now without me + + + align:start position:0% +where there are people now without me +they're capable of making more filters + + align:start position:0% +they're capable of making more filters + + + align:start position:0% +they're capable of making more filters +and maybe they can sell them for a small + + align:start position:0% +and maybe they can sell them for a small + + + align:start position:0% +and maybe they can sell them for a small +amount to be able to maintain them a + + align:start position:0% +amount to be able to maintain them a + + + align:start position:0% +amount to be able to maintain them a +community business the doing of all of + + align:start position:0% +community business the doing of all of + + + align:start position:0% +community business the doing of all of +that that seems to be a different realm + + align:start position:0% +that that seems to be a different realm + + + align:start position:0% +that that seems to be a different realm +it is yeah and I have not worked closely + + align:start position:0% +it is yeah and I have not worked closely + + + align:start position:0% +it is yeah and I have not worked closely +with communities as you're saying to set + + align:start position:0% +with communities as you're saying to set + + + align:start position:0% +with communities as you're saying to set +up facilities although and in South + + align:start position:0% +up facilities although and in South + + + align:start position:0% +up facilities although and in South +Texas I did I helped laid the groundwork + + align:start position:0% +Texas I did I helped laid the groundwork + + + align:start position:0% +Texas I did I helped laid the groundwork +and that facilities is working you saw + + align:start position:0% +and that facilities is working you saw + + + align:start position:0% +and that facilities is working you saw +pictures right but there are a number of + + align:start position:0% +pictures right but there are a number of + + + align:start position:0% +pictures right but there are a number of +groups who are doing the exact kind of + + align:start position:0% +groups who are doing the exact kind of + + + align:start position:0% +groups who are doing the exact kind of +work that you're mentioning and it's not + + align:start position:0% +work that you're mentioning and it's not + + + align:start position:0% +work that you're mentioning and it's not +from an arts or an art education + + align:start position:0% +from an arts or an art education + + + align:start position:0% +from an arts or an art education +perspective it is from that social + + align:start position:0% +perspective it is from that social + + + align:start position:0% +perspective it is from that social +entrepreneur realm that you're that + + align:start position:0% +entrepreneur realm that you're that + + + align:start position:0% +entrepreneur realm that you're that +you're talking about and I am very + + align:start position:0% +you're talking about and I am very + + + align:start position:0% +you're talking about and I am very +supportive of that piece and that is + + align:start position:0% +supportive of that piece and that is + + + align:start position:0% +supportive of that piece and that is +actually an intriguing component of what + + align:start position:0% +actually an intriguing component of what + + + align:start position:0% +actually an intriguing component of what +comes out of this this work it's that + + align:start position:0% +comes out of this this work it's that + + + align:start position:0% +comes out of this this work it's that +work that then has benefits in terms of + + align:start position:0% +work that then has benefits in terms of + + + align:start position:0% +work that then has benefits in terms of +health economics self-sustaining + + align:start position:0% +health economics self-sustaining + + + align:start position:0% +health economics self-sustaining +capacity that that I find intriguing and + + align:start position:0% +capacity that that I find intriguing and + + + align:start position:0% +capacity that that I find intriguing and +it's something that can be attempted + + align:start position:0% +it's something that can be attempted + + + align:start position:0% +it's something that can be attempted +where it's not intended to be a + + align:start position:0% +where it's not intended to be a + + + align:start position:0% +where it's not intended to be a +moneymaker initially it's intended to to + + align:start position:0% +moneymaker initially it's intended to to + + + align:start position:0% +moneymaker initially it's intended to to +save people's lives and and and to + + align:start position:0% +save people's lives and and and to + + + align:start position:0% +save people's lives and and and to +respond in that way so I'm curious about + + align:start position:0% +respond in that way so I'm curious about + + + align:start position:0% +respond in that way so I'm curious about +the longer term with this community in + + align:start position:0% +the longer term with this community in + + + align:start position:0% +the longer term with this community in +South Texas that you're working with + + align:start position:0% +South Texas that you're working with + + + align:start position:0% +South Texas that you're working with +obviously it sounds like there's a + + align:start position:0% +obviously it sounds like there's a + + + align:start position:0% +obviously it sounds like there's a +really pressing need so these water + + align:start position:0% +really pressing need so these water + + + align:start position:0% +really pressing need so these water +filters can meet that immediate need is + + align:start position:0% +filters can meet that immediate need is + + + align:start position:0% +filters can meet that immediate need is +the long-term goal still to kind of get + + align:start position:0% +the long-term goal still to kind of get + + + align:start position:0% +the long-term goal still to kind of get +a more traditional grid water setup for + + align:start position:0% +a more traditional grid water setup for + + + align:start position:0% +a more traditional grid water setup for +them yeah yes the origin of the filters + + align:start position:0% +them yeah yes the origin of the filters + + + align:start position:0% +them yeah yes the origin of the filters +was that they were supposed to be a + + align:start position:0% +was that they were supposed to be a + + + align:start position:0% +was that they were supposed to be a +first response to natural disaster and + + align:start position:0% +first response to natural disaster and + + + align:start position:0% +first response to natural disaster and +they were not supposed to be long-term + + align:start position:0% +they were not supposed to be long-term + + + align:start position:0% +they were not supposed to be long-term +their point of views temporary solutions + + align:start position:0% +their point of views temporary solutions + + + align:start position:0% +their point of views temporary solutions +unfortunately for some folks around the + + align:start position:0% +unfortunately for some folks around the + + + align:start position:0% +unfortunately for some folks around the +world these become more long-term + + align:start position:0% +world these become more long-term + + + align:start position:0% +world these become more long-term +responses what do you do when you're + + align:start position:0% +responses what do you do when you're + + + align:start position:0% +responses what do you do when you're +just starting out what's your advice for + + align:start position:0% +just starting out what's your advice for + + + align:start position:0% +just starting out what's your advice for +how you go about getting + + align:start position:0% +how you go about getting + + + align:start position:0% +how you go about getting +that's a tough one I think sometimes + + align:start position:0% +that's a tough one I think sometimes + + + align:start position:0% +that's a tough one I think sometimes +it's it's not about poking for the + + align:start position:0% +it's it's not about poking for the + + + align:start position:0% +it's it's not about poking for the +invitation initially sometimes you find + + align:start position:0% +invitation initially sometimes you find + + + align:start position:0% +invitation initially sometimes you find +ways to to become part of the community + + align:start position:0% +ways to to become part of the community + + + align:start position:0% +ways to to become part of the community +it's some level that might sound like oh + + align:start position:0% +it's some level that might sound like oh + + + align:start position:0% +it's some level that might sound like oh +but you're really kind of manipulating + + align:start position:0% +but you're really kind of manipulating + + + align:start position:0% +but you're really kind of manipulating +right because in the back of your mind + + align:start position:0% +right because in the back of your mind + + + align:start position:0% +right because in the back of your mind +you're saying okay at the right moment + + align:start position:0% +you're saying okay at the right moment + + + align:start position:0% +you're saying okay at the right moment +I'm gonna spring the question I'm gonna + + align:start position:0% +I'm gonna spring the question I'm gonna + + + align:start position:0% +I'm gonna spring the question I'm gonna +get the invitation that's not what I'm + + align:start position:0% +get the invitation that's not what I'm + + + align:start position:0% +get the invitation that's not what I'm +talking about what I'm talking about is + + align:start position:0% +talking about what I'm talking about is + + + align:start position:0% +talking about what I'm talking about is +being part of a community in doing the + + align:start position:0% +being part of a community in doing the + + + align:start position:0% +being part of a community in doing the +work in the community where the work + + align:start position:0% +work in the community where the work + + + align:start position:0% +work in the community where the work +that you're doing might be seen by folks + + align:start position:0% +that you're doing might be seen by folks + + + align:start position:0% +that you're doing might be seen by folks +who could invite you again that sounds + + align:start position:0% +who could invite you again that sounds + + + align:start position:0% +who could invite you again that sounds +like it's you some sort of nefarious + + align:start position:0% +like it's you some sort of nefarious + + + align:start position:0% +like it's you some sort of nefarious +manipulative component but not really I + + align:start position:0% +manipulative component but not really I + + + align:start position:0% +manipulative component but not really I +mean I think it's about continuing your + + align:start position:0% +mean I think it's about continuing your + + + align:start position:0% +mean I think it's about continuing your +work and staying visible and the + + align:start position:0% +work and staying visible and the + + + align:start position:0% +work and staying visible and the +invitations come there's a approach + + align:start position:0% +invitations come there's a approach + + + align:start position:0% +invitations come there's a approach +called arts entrepreneurship that is + + align:start position:0% +called arts entrepreneurship that is + + + align:start position:0% +called arts entrepreneurship that is +gaining traction in several universities + + align:start position:0% +gaining traction in several universities + + + align:start position:0% +gaining traction in several universities +have courses in art entrepreneurship + + align:start position:0% +have courses in art entrepreneurship + + + align:start position:0% +have courses in art entrepreneurship +arts entrepreneurship and minors and I + + align:start position:0% +arts entrepreneurship and minors and I + + + align:start position:0% +arts entrepreneurship and minors and I +think a few are starting majors as well + + align:start position:0% +think a few are starting majors as well + + + align:start position:0% +think a few are starting majors as well +or have majors because these other + + align:start position:0% +or have majors because these other + + + align:start position:0% +or have majors because these other +groups are doing this kind of work folks + + align:start position:0% +groups are doing this kind of work folks + + + align:start position:0% +groups are doing this kind of work folks +know about the water filter technology + + align:start position:0% +know about the water filter technology + + + align:start position:0% +know about the water filter technology +is starting to take off and people are + + align:start position:0% +is starting to take off and people are + + + align:start position:0% +is starting to take off and people are +collaborating they're entering into that + + align:start position:0% +collaborating they're entering into that + + + align:start position:0% +collaborating they're entering into that +space and what they're doing is they're + + align:start position:0% +space and what they're doing is they're + + + align:start position:0% +space and what they're doing is they're +they're making available for their + + align:start position:0% +they're making available for their + + + align:start position:0% +they're making available for their +learners k-12 learners possibilities + + align:start position:0% +learners k-12 learners possibilities + + + align:start position:0% +learners k-12 learners possibilities +that they might not have thought it's + + align:start position:0% +that they might not have thought it's + + + align:start position:0% +that they might not have thought it's +the curriculum work that I'm doing with + + align:start position:0% +the curriculum work that I'm doing with + + + align:start position:0% +the curriculum work that I'm doing with +with teachers I think that it becomes + + align:start position:0% +with teachers I think that it becomes + + + align:start position:0% +with teachers I think that it becomes +quite engaging great thank you all very + + align:start position:0% +quite engaging great thank you all very + + + align:start position:0% +quite engaging great thank you all very +much you very much yeah yeah I hope to + + align:start position:0% +much you very much yeah yeah I hope to + + + align:start position:0% +much you very much yeah yeah I hope to +see you tomorrow thank you thank you \ No newline at end of file diff --git a/SBe03vJr8-Y.txt b/SBe03vJr8-Y.txt new file mode 100644 index 0000000000000000000000000000000000000000..8f5f0babd61748f42aba44e1e34c1024684dbe77 --- /dev/null +++ b/SBe03vJr8-Y.txt @@ -0,0 +1,7515 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT open courseware continue + + align:start position:0% +will help MIT open courseware continue + + + align:start position:0% +will help MIT open courseware continue +to offer highquality educational + + align:start position:0% +to offer highquality educational + + + align:start position:0% +to offer highquality educational +resources for free to make a donation or + + align:start position:0% +resources for free to make a donation or + + + align:start position:0% +resources for free to make a donation or +view additional materials from hundreds + + align:start position:0% +view additional materials from hundreds + + + align:start position:0% +view additional materials from hundreds +of MIT courses visit mitop courseware at + + align:start position:0% + + + + align:start position:0% + +ocw.mit.edu good morning uh my talk this + + align:start position:0% +ocw.mit.edu good morning uh my talk this + + + align:start position:0% +ocw.mit.edu good morning uh my talk this +morning is going to be uh as it states + + align:start position:0% +morning is going to be uh as it states + + + align:start position:0% +morning is going to be uh as it states +there uh about pilgrimage and um first + + align:start position:0% +there uh about pilgrimage and um first + + + align:start position:0% +there uh about pilgrimage and um first +question I'd like to do is kind of + + align:start position:0% +question I'd like to do is kind of + + + align:start position:0% +question I'd like to do is kind of +introduce us to the kind of broad scope + + align:start position:0% +introduce us to the kind of broad scope + + + align:start position:0% +introduce us to the kind of broad scope +uh within this kind of mil which when + + align:start position:0% +uh within this kind of mil which when + + + align:start position:0% +uh within this kind of mil which when +within which within we're situated uh + + align:start position:0% +within which within we're situated uh + + + align:start position:0% +within which within we're situated uh +when we talk about pilgrimage as this + + align:start position:0% +when we talk about pilgrimage as this + + + align:start position:0% +when we talk about pilgrimage as this +kind of overarching global phenomenon um + + align:start position:0% +kind of overarching global phenomenon um + + + align:start position:0% +kind of overarching global phenomenon um +and the first question I would pose to + + align:start position:0% +and the first question I would pose to + + + align:start position:0% +and the first question I would pose to +you is um you know besides being + + align:start position:0% +you is um you know besides being + + + align:start position:0% +you is um you know besides being +pilgrims as we kind of as I sort of laid + + align:start position:0% +pilgrims as we kind of as I sort of laid + + + align:start position:0% +pilgrims as we kind of as I sort of laid +out there in the title what do these + + align:start position:0% +out there in the title what do these + + + align:start position:0% +out there in the title what do these +people have in common right + + align:start position:0% +people have in common right + + + align:start position:0% +people have in common right +uh we see people in different um uh sort + + align:start position:0% +uh we see people in different um uh sort + + + align:start position:0% +uh we see people in different um uh sort +of actions here and here are the places + + align:start position:0% +of actions here and here are the places + + + align:start position:0% +of actions here and here are the places +that they're all sort of associated with + + align:start position:0% +that they're all sort of associated with + + + align:start position:0% +that they're all sort of associated with +right so they're all + + align:start position:0% +right so they're all + + + align:start position:0% +right so they're all +going to a certain place right so the + + align:start position:0% +going to a certain place right so the + + + align:start position:0% +going to a certain place right so the +first one obviously on the left here + + align:start position:0% +first one obviously on the left here + + + align:start position:0% +first one obviously on the left here +this is the Kaba in Mecca we have St + + align:start position:0% +this is the Kaba in Mecca we have St + + + align:start position:0% +this is the Kaba in Mecca we have St +James compostella in Spain the mahabi + + align:start position:0% +James compostella in Spain the mahabi + + + align:start position:0% +James compostella in Spain the mahabi +temple in India and of course graceand + + align:start position:0% +temple in India and of course graceand + + + align:start position:0% +temple in India and of course graceand +in Memphis + + align:start position:0% +in Memphis + + + align:start position:0% +in Memphis +Tennessee um so questions I'd like to + + align:start position:0% +Tennessee um so questions I'd like to + + + align:start position:0% +Tennessee um so questions I'd like to +ask to kind of frame our conversation + + align:start position:0% +ask to kind of frame our conversation + + + align:start position:0% +ask to kind of frame our conversation +today really uh center + + align:start position:0% +today really uh center + + + align:start position:0% +today really uh center +around kind of problematizing some of + + align:start position:0% +around kind of problematizing some of + + + align:start position:0% +around kind of problematizing some of +these Notions that we've inherited uh + + align:start position:0% +these Notions that we've inherited uh + + + align:start position:0% +these Notions that we've inherited uh +with this term pilgrimage um we're + + align:start position:0% +with this term pilgrimage um we're + + + align:start position:0% +with this term pilgrimage um we're +surrounded by it uh in our popular + + align:start position:0% +surrounded by it uh in our popular + + + align:start position:0% +surrounded by it uh in our popular +culture today uh we've got all kinds of + + align:start position:0% +culture today uh we've got all kinds of + + + align:start position:0% +culture today uh we've got all kinds of +examples um we've got uh National + + align:start position:0% +examples um we've got uh National + + + align:start position:0% +examples um we've got uh National +Geographic uh magazines and um this is a + + align:start position:0% +Geographic uh magazines and um this is a + + + align:start position:0% +Geographic uh magazines and um this is a +French magazine that's com it's a themed + + align:start position:0% +French magazine that's com it's a themed + + + align:start position:0% +French magazine that's com it's a themed +magazine that just came out a month ago + + align:start position:0% +magazine that just came out a month ago + + + align:start position:0% +magazine that just came out a month ago +um you know and and we're surrounded + + align:start position:0% +um you know and and we're surrounded + + + align:start position:0% +um you know and and we're surrounded +with images uh of pilgrimage people + + align:start position:0% +with images uh of pilgrimage people + + + align:start position:0% +with images uh of pilgrimage people +going on these great travels and + + align:start position:0% +going on these great travels and + + + align:start position:0% +going on these great travels and +Journeys to different places uh + + align:start position:0% +Journeys to different places uh + + + align:start position:0% +Journeys to different places uh +throughout the world and so I just I + + align:start position:0% +throughout the world and so I just I + + + align:start position:0% +throughout the world and so I just I +think that uh this lecture is an + + align:start position:0% +think that uh this lecture is an + + + align:start position:0% +think that uh this lecture is an +opportunity to kind of uh you know try + + align:start position:0% +opportunity to kind of uh you know try + + + align:start position:0% +opportunity to kind of uh you know try +to begin to understand those some of + + align:start position:0% +to begin to understand those some of + + + align:start position:0% +to begin to understand those some of +those issues um + + align:start position:0% +those issues um + + + align:start position:0% +those issues um +it's it is a very contemporary + + align:start position:0% +it's it is a very contemporary + + + align:start position:0% +it's it is a very contemporary +phenomenon still um even though the bulk + + align:start position:0% +phenomenon still um even though the bulk + + + align:start position:0% +phenomenon still um even though the bulk +of this lecture will be a historical uh + + align:start position:0% +of this lecture will be a historical uh + + + align:start position:0% +of this lecture will be a historical uh +discussion the I would like to situate + + align:start position:0% +discussion the I would like to situate + + + align:start position:0% +discussion the I would like to situate +it within a cont temporary framework of + + align:start position:0% +it within a cont temporary framework of + + + align:start position:0% +it within a cont temporary framework of +um because it's very relevant today I + + align:start position:0% +um because it's very relevant today I + + + align:start position:0% +um because it's very relevant today I +mean as this is from the National + + align:start position:0% +mean as this is from the National + + + align:start position:0% +mean as this is from the National +Geographic website which was also + + align:start position:0% +Geographic website which was also + + + align:start position:0% +Geographic website which was also +published in a magazine a few months ago + + align:start position:0% +published in a magazine a few months ago + + + align:start position:0% +published in a magazine a few months ago +which talks about um Global pilgrimage + + align:start position:0% +which talks about um Global pilgrimage + + + align:start position:0% +which talks about um Global pilgrimage +really it tries to kind of elicit uh + + align:start position:0% +really it tries to kind of elicit uh + + + align:start position:0% +really it tries to kind of elicit uh +kind of sort of essentializes a lot of + + align:start position:0% +kind of sort of essentializes a lot of + + + align:start position:0% +kind of sort of essentializes a lot of +different pilgrimages around the world + + align:start position:0% +different pilgrimages around the world + + + align:start position:0% +different pilgrimages around the world +and um it highlights and on their + + align:start position:0% +and um it highlights and on their + + + align:start position:0% +and um it highlights and on their +website they actually have a um an + + align:start position:0% +website they actually have a um an + + + align:start position:0% +website they actually have a um an +interactive map where you can click and + + align:start position:0% +interactive map where you can click and + + + align:start position:0% +interactive map where you can click and +read all about the different types of + + align:start position:0% +read all about the different types of + + + align:start position:0% +read all about the different types of +pilgrimages around the world um and you + + align:start position:0% +pilgrimages around the world um and you + + + align:start position:0% +pilgrimages around the world um and you +know again just to kind of remind us of + + align:start position:0% +know again just to kind of remind us of + + + align:start position:0% +know again just to kind of remind us of +the Contemporary + + align:start position:0% +the Contemporary + + + align:start position:0% +the Contemporary +contemporariness really of the situ of + + align:start position:0% +contemporariness really of the situ of + + + align:start position:0% +contemporariness really of the situ of +of pilgrimage it does have over 300 + + align:start position:0% +of pilgrimage it does have over 300 + + + align:start position:0% +of pilgrimage it does have over 300 +million Travelers per year are traveling + + align:start position:0% +million Travelers per year are traveling + + + align:start position:0% +million Travelers per year are traveling +on some kind of Faith tourism or + + align:start position:0% +on some kind of Faith tourism or + + + align:start position:0% +on some kind of Faith tourism or +religious programm of some sort and it + + align:start position:0% +religious programm of some sort and it + + + align:start position:0% +religious programm of some sort and it +is an $18 billion year Revenue + + align:start position:0% +is an $18 billion year Revenue + + + align:start position:0% +is an $18 billion year Revenue +generating industry so this is something + + align:start position:0% +generating industry so this is something + + + align:start position:0% +generating industry so this is something +that's extremely um um relevant and so + + align:start position:0% +that's extremely um um relevant and so + + + align:start position:0% +that's extremely um um relevant and so +here's the National Geographic + + align:start position:0% +here's the National Geographic + + + align:start position:0% +here's the National Geographic +interactive map and you can kind of + + align:start position:0% +interactive map and you can kind of + + + align:start position:0% +interactive map and you can kind of +click on all these different places and + + align:start position:0% +click on all these different places and + + + align:start position:0% +click on all these different places and +try to gain an understanding uh + + align:start position:0% +try to gain an understanding uh + + + align:start position:0% +try to gain an understanding uh +and so we we can understand pilgrimage + + align:start position:0% +and so we we can understand pilgrimage + + + align:start position:0% +and so we we can understand pilgrimage +as this as you know occurring all over + + align:start position:0% +as this as you know occurring all over + + + align:start position:0% +as this as you know occurring all over +the world but for our sake for this + + align:start position:0% +the world but for our sake for this + + + align:start position:0% +the world but for our sake for this +lecture I think it's very important to + + align:start position:0% +lecture I think it's very important to + + + align:start position:0% +lecture I think it's very important to +kind of hone in on on uh focus on some + + align:start position:0% +kind of hone in on on uh focus on some + + + align:start position:0% +kind of hone in on on uh focus on some +specific Traditions So today we're going + + align:start position:0% +specific Traditions So today we're going + + + align:start position:0% +specific Traditions So today we're going +to be looking at an example from Egypt + + align:start position:0% +to be looking at an example from Egypt + + + align:start position:0% +to be looking at an example from Egypt +uh early Buddhism Islam and + + align:start position:0% +uh early Buddhism Islam and + + + align:start position:0% +uh early Buddhism Islam and +Christianity um but first I'd like to + + align:start position:0% +Christianity um but first I'd like to + + + align:start position:0% +Christianity um but first I'd like to +kind of problematize what pilgrimage is + + align:start position:0% +kind of problematize what pilgrimage is + + + align:start position:0% +kind of problematize what pilgrimage is +what it means uh what's going on here + + align:start position:0% +what it means uh what's going on here + + + align:start position:0% +what it means uh what's going on here +um the um the question is what is a + + align:start position:0% +um the um the question is what is a + + + align:start position:0% +um the um the question is what is a +pilgrimage right so it's usually a + + align:start position:0% +pilgrimage right so it's usually a + + + align:start position:0% +pilgrimage right so it's usually a +journey of some sort somebody's + + align:start position:0% +journey of some sort somebody's + + + align:start position:0% +journey of some sort somebody's +traveling to some degree uh to see some + + align:start position:0% +traveling to some degree uh to see some + + + align:start position:0% +traveling to some degree uh to see some +sacred or some holy either a relic or a + + align:start position:0% +sacred or some holy either a relic or a + + + align:start position:0% +sacred or some holy either a relic or a +space or something um and these people + + align:start position:0% +space or something um and these people + + + align:start position:0% +space or something um and these people +usually pay some kind of homage or + + align:start position:0% +usually pay some kind of homage or + + + align:start position:0% +usually pay some kind of homage or +respect uh and they they they perform + + align:start position:0% +respect uh and they they they perform + + + align:start position:0% +respect uh and they they they perform +this journey um out of some kind of + + align:start position:0% +this journey um out of some kind of + + + align:start position:0% +this journey um out of some kind of +sense of a Duty or some kind of + + align:start position:0% +sense of a Duty or some kind of + + + align:start position:0% +sense of a Duty or some kind of +responsibility there's something that + + align:start position:0% +responsibility there's something that + + + align:start position:0% +responsibility there's something that +kind of you know gets them to go on it + + align:start position:0% +kind of you know gets them to go on it + + + align:start position:0% +kind of you know gets them to go on it +uh and what a pilgrim is is not + + align:start position:0% +uh and what a pilgrim is is not + + + align:start position:0% +uh and what a pilgrim is is not +necessarily um you know we're not really + + align:start position:0% +necessarily um you know we're not really + + + align:start position:0% +necessarily um you know we're not really +going to cover that specifically because + + align:start position:0% +going to cover that specifically because + + + align:start position:0% +going to cover that specifically because +that's more of a sort of an + + align:start position:0% +that's more of a sort of an + + + align:start position:0% +that's more of a sort of an +anthropological thing but we we are + + align:start position:0% +anthropological thing but we we are + + + align:start position:0% +anthropological thing but we we are +going to address a couple issues related + + align:start position:0% +going to address a couple issues related + + + align:start position:0% +going to address a couple issues related +to pilgrims because they are obviously + + align:start position:0% +to pilgrims because they are obviously + + + align:start position:0% +to pilgrims because they are obviously +very diverse and they're the reason that + + align:start position:0% +very diverse and they're the reason that + + + align:start position:0% +very diverse and they're the reason that +pilgrimages exist so um to some extent + + align:start position:0% +pilgrimages exist so um to some extent + + + align:start position:0% +pilgrimages exist so um to some extent +we need to understand that what a + + align:start position:0% +we need to understand that what a + + + align:start position:0% +we need to understand that what a +pilgrim is and who who they are very + + align:start position:0% +pilgrim is and who who they are very + + + align:start position:0% +pilgrim is and who who they are very +basically um and I've tried to kind of + + align:start position:0% +basically um and I've tried to kind of + + + align:start position:0% +basically um and I've tried to kind of +outline or reduce some of the themes of + + align:start position:0% +outline or reduce some of the themes of + + + align:start position:0% +outline or reduce some of the themes of +pilgrimage to three kind of very basic + + align:start position:0% +pilgrimage to three kind of very basic + + + align:start position:0% +pilgrimage to three kind of very basic +um um kind of ideas so there's Faith + + align:start position:0% +um um kind of ideas so there's Faith + + + align:start position:0% +um um kind of ideas so there's Faith +obviously which is involved and this is + + align:start position:0% +obviously which is involved and this is + + + align:start position:0% +obviously which is involved and this is +not necessarily religious uh it can be + + align:start position:0% +not necessarily religious uh it can be + + + align:start position:0% +not necessarily religious uh it can be +uh some kind of spiritual entity or + + align:start position:0% +uh some kind of spiritual entity or + + + align:start position:0% +uh some kind of spiritual entity or +personage as I mentioned can be + + align:start position:0% +personage as I mentioned can be + + + align:start position:0% +personage as I mentioned can be +religious or secular as we saw with + + align:start position:0% +religious or secular as we saw with + + + align:start position:0% +religious or secular as we saw with +Elvis already um people can believe in + + align:start position:0% +Elvis already um people can believe in + + + align:start position:0% +Elvis already um people can believe in +something related to somebody um but + + align:start position:0% +something related to somebody um but + + + align:start position:0% +something related to somebody um but +most importantly there's a desire to do + + align:start position:0% +most importantly there's a desire to do + + + align:start position:0% +most importantly there's a desire to do +something about it and so um that's + + align:start position:0% +something about it and so um that's + + + align:start position:0% +something about it and so um that's +where movement comes in and so Movement + + align:start position:0% +where movement comes in and so Movement + + + align:start position:0% +where movement comes in and so Movement +we can basically understand it as this + + align:start position:0% +we can basically understand it as this + + + align:start position:0% +we can basically understand it as this +this WEA um you know in some traditions + + align:start position:0% +this WEA um you know in some traditions + + + align:start position:0% +this WEA um you know in some traditions +we're going to talk about + + align:start position:0% +we're going to talk about + + + align:start position:0% +we're going to talk about +circumambulation and some some uh + + align:start position:0% +circumambulation and some some uh + + + align:start position:0% +circumambulation and some some uh +Traditions we're going to talk about + + align:start position:0% +Traditions we're going to talk about + + + align:start position:0% +Traditions we're going to talk about +procession there's this constant thread + + align:start position:0% +procession there's this constant thread + + + align:start position:0% +procession there's this constant thread +of movement which is kind of a thread + + align:start position:0% +of movement which is kind of a thread + + + align:start position:0% +of movement which is kind of a thread +within all of these different Traditions + + align:start position:0% +within all of these different Traditions + + + align:start position:0% +within all of these different Traditions +or something's moving right whether it's + + align:start position:0% +or something's moving right whether it's + + + align:start position:0% +or something's moving right whether it's +the sacred or the or the profane or + + align:start position:0% +the sacred or the or the profane or + + + align:start position:0% +the sacred or the or the profane or +whether it's people or whether it's an + + align:start position:0% +whether it's people or whether it's an + + + align:start position:0% +whether it's people or whether it's an +object things are things are constantly + + align:start position:0% +object things are things are constantly + + + align:start position:0% +object things are things are constantly +moving which is obviously very important + + align:start position:0% +moving which is obviously very important + + + align:start position:0% +moving which is obviously very important +for us spatially uh and of course that + + align:start position:0% +for us spatially uh and of course that + + + align:start position:0% +for us spatially uh and of course that +brings me to the differentiation of + + align:start position:0% +brings me to the differentiation of + + + align:start position:0% +brings me to the differentiation of +space and so space really uh as a key to + + align:start position:0% +space and so space really uh as a key to + + + align:start position:0% +space and so space really uh as a key to +this um this understanding uh + + align:start position:0% +this um this understanding uh + + + align:start position:0% +this um this understanding uh +understanding the differences in the + + align:start position:0% +understanding the differences in the + + + align:start position:0% +understanding the differences in the +conceptions of space between these + + align:start position:0% +conceptions of space between these + + + align:start position:0% +conceptions of space between these +different traditions and how the + + align:start position:0% +different traditions and how the + + + align:start position:0% +different traditions and how the +different Traditions understand this + + align:start position:0% +different Traditions understand this + + + align:start position:0% +different Traditions understand this +notion of the Sacred and the profane + + align:start position:0% +notion of the Sacred and the profane + + + align:start position:0% +notion of the Sacred and the profane +right so we we've kind of inherited this + + align:start position:0% +right so we we've kind of inherited this + + + align:start position:0% +right so we we've kind of inherited this +very this you know very dualistic uh + + align:start position:0% +very this you know very dualistic uh + + + align:start position:0% +very this you know very dualistic uh +diagram of the Sacred versus the profane + + align:start position:0% +diagram of the Sacred versus the profane + + + align:start position:0% +diagram of the Sacred versus the profane +right they're always kind of like + + align:start position:0% +right they're always kind of like + + + align:start position:0% +right they're always kind of like +opposed to one another uh in our kind of + + align:start position:0% +opposed to one another uh in our kind of + + + align:start position:0% +opposed to one another uh in our kind of +traditional understanding you're either + + align:start position:0% +traditional understanding you're either + + + align:start position:0% +traditional understanding you're either +sacred or profane spaces can be sacred + + align:start position:0% +sacred or profane spaces can be sacred + + + align:start position:0% +sacred or profane spaces can be sacred +or profane and so what I would really + + align:start position:0% +or profane and so what I would really + + + align:start position:0% +or profane and so what I would really +like to do is challenge our + + align:start position:0% +like to do is challenge our + + + align:start position:0% +like to do is challenge our +understanding of that and this is again + + align:start position:0% +understanding of that and this is again + + + align:start position:0% +understanding of that and this is again +this is the sort of traditional path + + align:start position:0% +this is the sort of traditional path + + + align:start position:0% +this is the sort of traditional path +that a pilgrim takes right they move + + align:start position:0% +that a pilgrim takes right they move + + + align:start position:0% +that a pilgrim takes right they move +from the profane through or into the s + + align:start position:0% +from the profane through or into the s + + + align:start position:0% +from the profane through or into the s +and then they come back to their profane + + align:start position:0% +and then they come back to their profane + + + align:start position:0% +and then they come back to their profane +existence somehow + + align:start position:0% +existence somehow + + + align:start position:0% +existence somehow +transformed so how does that + + align:start position:0% +transformed so how does that + + + align:start position:0% +transformed so how does that +transformation occur again anthropology + + align:start position:0% +transformation occur again anthropology + + + align:start position:0% +transformation occur again anthropology +here does a little bit of a job and they + + align:start position:0% +here does a little bit of a job and they + + + align:start position:0% +here does a little bit of a job and they +sort of help me out with this + + align:start position:0% +sort of help me out with this + + + align:start position:0% +sort of help me out with this +understanding uh the anthropologists + + align:start position:0% +understanding uh the anthropologists + + + align:start position:0% +understanding uh the anthropologists +have been studying this since like + + align:start position:0% +have been studying this since like + + + align:start position:0% +have been studying this since like +really the 60s and so um there's three + + align:start position:0% +really the 60s and so um there's three + + + align:start position:0% +really the 60s and so um there's three +quick stages of of a pilgrimage uh + + align:start position:0% +quick stages of of a pilgrimage uh + + + align:start position:0% +quick stages of of a pilgrimage uh +Journey that I'd like to kind of elicit + + align:start position:0% +Journey that I'd like to kind of elicit + + + align:start position:0% +Journey that I'd like to kind of elicit +here and this is the prelimin Lial and + + align:start position:0% +here and this is the prelimin Lial and + + + align:start position:0% +here and this is the prelimin Lial and +post liin right so we Anthropologist + + align:start position:0% +post liin right so we Anthropologist + + + align:start position:0% +post liin right so we Anthropologist +kind of like this to a graduation + + align:start position:0% +kind of like this to a graduation + + + align:start position:0% +kind of like this to a graduation +ceremony where the prelimin is the + + align:start position:0% +ceremony where the prelimin is the + + + align:start position:0% +ceremony where the prelimin is the +separation phase right where students + + align:start position:0% +separation phase right where students + + + align:start position:0% +separation phase right where students +are with their parents and they're kind + + align:start position:0% +are with their parents and they're kind + + + align:start position:0% +are with their parents and they're kind +of Milling about and then they all kind + + align:start position:0% +of Milling about and then they all kind + + + align:start position:0% +of Milling about and then they all kind +of they get their robes on right so + + align:start position:0% +of they get their robes on right so + + + align:start position:0% +of they get their robes on right so +they're differentiating themselves then + + align:start position:0% +they're differentiating themselves then + + + align:start position:0% +they're differentiating themselves then +they all go sit in the middle of the uh + + align:start position:0% +they all go sit in the middle of the uh + + + align:start position:0% +they all go sit in the middle of the uh +in the middle they are separated from + + align:start position:0% +in the middle they are separated from + + + align:start position:0% +in the middle they are separated from +their parents and families they sit + + align:start position:0% +their parents and families they sit + + + align:start position:0% +their parents and families they sit +there then they're in this Lial phase + + align:start position:0% +there then they're in this Lial phase + + + align:start position:0% +there then they're in this Lial phase +where there's this transitional phase + + align:start position:0% +where there's this transitional phase + + + align:start position:0% +where there's this transitional phase +where people give their you know + + align:start position:0% +where people give their you know + + + align:start position:0% +where people give their you know +lectures and they talk about how great + + align:start position:0% +lectures and they talk about how great + + + align:start position:0% +lectures and they talk about how great +the class is and what happened that year + + align:start position:0% +the class is and what happened that year + + + align:start position:0% +the class is and what happened that year +and all this things and so um then this + + align:start position:0% +and all this things and so um then this + + + align:start position:0% +and all this things and so um then this +notion of communitas kind of evolves out + + align:start position:0% +notion of communitas kind of evolves out + + + align:start position:0% +notion of communitas kind of evolves out +of that right so there's this feeling of + + align:start position:0% +of that right so there's this feeling of + + + align:start position:0% +of that right so there's this feeling of +a community that they're together with + + align:start position:0% +a community that they're together with + + + align:start position:0% +a community that they're together with +people and so um very basically you you + + align:start position:0% +people and so um very basically you you + + + align:start position:0% +people and so um very basically you you +the anthropologists talk about how + + align:start position:0% +the anthropologists talk about how + + + align:start position:0% +the anthropologists talk about how +there's this um together feeling that + + align:start position:0% +there's this um together feeling that + + + align:start position:0% +there's this um together feeling that +they're doing something together and + + align:start position:0% +they're doing something together and + + + align:start position:0% +they're doing something together and +then the post liino is the + + align:start position:0% +then the post liino is the + + + align:start position:0% +then the post liino is the +reincorporation into society you have th + + align:start position:0% +reincorporation into society you have th + + + align:start position:0% +reincorporation into society you have th +graduated you've been given your degree + + align:start position:0% +graduated you've been given your degree + + + align:start position:0% +graduated you've been given your degree +and now you're reincorporated into + + align:start position:0% +and now you're reincorporated into + + + align:start position:0% +and now you're reincorporated into +society as an individual you you're part + + align:start position:0% +society as an individual you you're part + + + align:start position:0% +society as an individual you you're part +of this community of people with a + + align:start position:0% +of this community of people with a + + + align:start position:0% +of this community of people with a +degree right so this is kind of but I'd + + align:start position:0% +degree right so this is kind of but I'd + + + align:start position:0% +degree right so this is kind of but I'd +like us to keep in mind this notion of + + align:start position:0% +like us to keep in mind this notion of + + + align:start position:0% +like us to keep in mind this notion of +communitas as we move forward um the + + align:start position:0% +communitas as we move forward um the + + + align:start position:0% +communitas as we move forward um the +first um kind of example here in um + + align:start position:0% +first um kind of example here in um + + + align:start position:0% +first um kind of example here in um +slide 16 is the uh we're going to look + + align:start position:0% +slide 16 is the uh we're going to look + + + align:start position:0% +slide 16 is the uh we're going to look +at a sort of an ancient example in the + + align:start position:0% +at a sort of an ancient example in the + + + align:start position:0% +at a sort of an ancient example in the +New Kingdom of um in Egypt uh the carac + + align:start position:0% +New Kingdom of um in Egypt uh the carac + + + align:start position:0% +New Kingdom of um in Egypt uh the carac +and so this is B very basically where + + align:start position:0% +and so this is B very basically where + + + align:start position:0% +and so this is B very basically where +it's located um in Africa + + align:start position:0% +it's located um in Africa + + + align:start position:0% +it's located um in Africa +and um this is a procession basically + + align:start position:0% +and um this is a procession basically + + + align:start position:0% +and um this is a procession basically +it's it's it's a very early form of + + align:start position:0% +it's it's it's a very early form of + + + align:start position:0% +it's it's it's a very early form of +pilgrimage and um really it takes on + + align:start position:0% +pilgrimage and um really it takes on + + + align:start position:0% +pilgrimage and um really it takes on +this notion of the of the procession to + + align:start position:0% +this notion of the of the procession to + + + align:start position:0% +this notion of the of the procession to +a very specific um in a very specific + + align:start position:0% +a very specific um in a very specific + + + align:start position:0% +a very specific um in a very specific +manner people aren't necessarily coming + + align:start position:0% +manner people aren't necessarily coming + + + align:start position:0% +manner people aren't necessarily coming +from extremely far distances to come to + + align:start position:0% +from extremely far distances to come to + + + align:start position:0% +from extremely far distances to come to +thieves this general area here that we + + align:start position:0% +thieves this general area here that we + + + align:start position:0% +thieves this general area here that we +can see but um there are people within + + align:start position:0% +can see but um there are people within + + + align:start position:0% +can see but um there are people within +thieves that um and this is a very + + align:start position:0% +thieves that um and this is a very + + + align:start position:0% +thieves that um and this is a very +unique um procession in that the the + + align:start position:0% +unique um procession in that the the + + + align:start position:0% +unique um procession in that the the +notion of our notion of the Sacred that + + align:start position:0% +notion of our notion of the Sacred that + + + align:start position:0% +notion of our notion of the Sacred that +we talked about just briefly earlier uh + + align:start position:0% +we talked about just briefly earlier uh + + + align:start position:0% +we talked about just briefly earlier uh +the sacred is actually very interesting + + align:start position:0% +the sacred is actually very interesting + + + align:start position:0% +the sacred is actually very interesting +because it's cooc there are the temples + + align:start position:0% +because it's cooc there are the temples + + + align:start position:0% +because it's cooc there are the temples +themselves are sacred and the spaces are + + align:start position:0% +themselves are sacred and the spaces are + + + align:start position:0% +themselves are sacred and the spaces are +sacred within them but the there's + + align:start position:0% +sacred within them but the there's + + + align:start position:0% +sacred within them but the there's +something very interesting here where + + align:start position:0% +something very interesting here where + + + align:start position:0% +something very interesting here where +the sacred is actually moved so the the + + align:start position:0% +the sacred is actually moved so the the + + + align:start position:0% +the sacred is actually moved so the the +gods actually leave the temples and are + + align:start position:0% +gods actually leave the temples and are + + + align:start position:0% +gods actually leave the temples and are +processed through these different areas + + align:start position:0% +processed through these different areas + + + align:start position:0% +processed through these different areas +and we can see here from this first uh + + align:start position:0% +and we can see here from this first uh + + + align:start position:0% +and we can see here from this first uh +example this is the there's two main + + align:start position:0% +example this is the there's two main + + + align:start position:0% +example this is the there's two main +festivals I'd like to very briefly talk + + align:start position:0% +festivals I'd like to very briefly talk + + + align:start position:0% +festivals I'd like to very briefly talk +about there's the opet festival which is + + align:start position:0% +about there's the opet festival which is + + + align:start position:0% +about there's the opet festival which is +this essentially this route all right so + + align:start position:0% +this essentially this route all right so + + + align:start position:0% +this essentially this route all right so +very basically uh Carnac Temple here and + + align:start position:0% +very basically uh Carnac Temple here and + + + align:start position:0% +very basically uh Carnac Temple here and +then the um the procession there's two + + align:start position:0% +then the um the procession there's two + + + align:start position:0% +then the um the procession there's two +different there's a couple different + + align:start position:0% +different there's a couple different + + + align:start position:0% +different there's a couple different +ways in which this happens but the + + align:start position:0% +ways in which this happens but the + + + align:start position:0% +ways in which this happens but the +initial the earlier kingdoms uh example + + align:start position:0% +initial the earlier kingdoms uh example + + + align:start position:0% +initial the earlier kingdoms uh example +leaves from Carnac goes takes the land + + align:start position:0% +leaves from Carnac goes takes the land + + + align:start position:0% +leaves from Carnac goes takes the land +route to Luxor then goes in the Nile and + + align:start position:0% +route to Luxor then goes in the Nile and + + + align:start position:0% +route to Luxor then goes in the Nile and +then come so it comes back Thea the Nile + + align:start position:0% +then come so it comes back Thea the Nile + + + align:start position:0% +then come so it comes back Thea the Nile +um and so what's happening is Amun the + + align:start position:0% +um and so what's happening is Amun the + + + align:start position:0% +um and so what's happening is Amun the +god Amun uh is sort of he inhabits + + align:start position:0% +god Amun uh is sort of he inhabits + + + align:start position:0% +god Amun uh is sort of he inhabits +Carnac right so he's removed his image + + align:start position:0% +Carnac right so he's removed his image + + + align:start position:0% +Carnac right so he's removed his image +is removed and thus their understanding + + align:start position:0% +is removed and thus their understanding + + + align:start position:0% +is removed and thus their understanding +of the god so they they put him on a + + align:start position:0% +of the god so they they put him on a + + + align:start position:0% +of the god so they they put him on a +bark and then which is the ship and I'll + + align:start position:0% +bark and then which is the ship and I'll + + + align:start position:0% +bark and then which is the ship and I'll +show you that in a minute but I'd like + + align:start position:0% +show you that in a minute but I'd like + + + align:start position:0% +show you that in a minute but I'd like +to first show you the other this is the + + align:start position:0% +to first show you the other this is the + + + align:start position:0% +to first show you the other this is the +Feast of the valley and this route uh + + align:start position:0% +Feast of the valley and this route uh + + + align:start position:0% +Feast of the valley and this route uh +includes this is a little bit later + + align:start position:0% +includes this is a little bit later + + + align:start position:0% +includes this is a little bit later +because it includes the Temple of Hut + + align:start position:0% +because it includes the Temple of Hut + + + align:start position:0% +because it includes the Temple of Hut +and the med Tabu over here so this again + + align:start position:0% +and the med Tabu over here so this again + + + align:start position:0% +and the med Tabu over here so this again +and and the the are double-headed + + align:start position:0% +and and the the are double-headed + + + align:start position:0% +and and the the are double-headed +because there's different in different + + align:start position:0% +because there's different in different + + + align:start position:0% +because there's different in different +area eras uh The Roots went different + + align:start position:0% +area eras uh The Roots went different + + + align:start position:0% +area eras uh The Roots went different +way sometimes they went out on the water + + align:start position:0% +way sometimes they went out on the water + + + align:start position:0% +way sometimes they went out on the water +and came back on the water and sometimes + + align:start position:0% +and came back on the water and sometimes + + + align:start position:0% +and came back on the water and sometimes +they went over the + + align:start position:0% +they went over the + + + align:start position:0% +they went over the +land um and so here it is a kind of a + + align:start position:0% +land um and so here it is a kind of a + + + align:start position:0% +land um and so here it is a kind of a +plan view again here you can see how + + align:start position:0% +plan view again here you can see how + + + align:start position:0% +plan view again here you can see how +there's multiple Pathways here but the + + align:start position:0% +there's multiple Pathways here but the + + + align:start position:0% +there's multiple Pathways here but the +key to our understanding is and just a + + align:start position:0% +key to our understanding is and just a + + + align:start position:0% +key to our understanding is and just a +couple views here this is of the ram + + align:start position:0% +couple views here this is of the ram + + + align:start position:0% +couple views here this is of the ram +headed spin so this is this you can + + align:start position:0% +headed spin so this is this you can + + + align:start position:0% +headed spin so this is this you can +obviously get a sense of this very + + align:start position:0% +obviously get a sense of this very + + + align:start position:0% +obviously get a sense of this very +hieratic um sort of processional space + + align:start position:0% +hieratic um sort of processional space + + + align:start position:0% +hieratic um sort of processional space +that that was occurring um and so my my + + align:start position:0% +that that was occurring um and so my my + + + align:start position:0% +that that was occurring um and so my my +kind of diagram here sort of tries to + + align:start position:0% +kind of diagram here sort of tries to + + + align:start position:0% +kind of diagram here sort of tries to +understand this notion of the Sacred in + + align:start position:0% +understand this notion of the Sacred in + + + align:start position:0% +understand this notion of the Sacred in +the profane in this Carnac uh example + + align:start position:0% +the profane in this Carnac uh example + + + align:start position:0% +the profane in this Carnac uh example +and so I would put forward that the + + align:start position:0% +and so I would put forward that the + + + align:start position:0% +and so I would put forward that the +sacred is not necess is is not only an + + align:start position:0% +sacred is not necess is is not only an + + + align:start position:0% +sacred is not necess is is not only an +object here the little sacred which is + + align:start position:0% +object here the little sacred which is + + + align:start position:0% +object here the little sacred which is +the image of the god or The God himself + + align:start position:0% +the image of the god or The God himself + + + align:start position:0% +the image of the god or The God himself +uh but he's within the sacred Temple + + align:start position:0% +uh but he's within the sacred Temple + + + align:start position:0% +uh but he's within the sacred Temple +complex and he's literally processed + + align:start position:0% +complex and he's literally processed + + + align:start position:0% +complex and he's literally processed +through profane spaces to go visit his + + align:start position:0% +through profane spaces to go visit his + + + align:start position:0% +through profane spaces to go visit his +son konu or his wife mut so he's going + + align:start position:0% +son konu or his wife mut so he's going + + + align:start position:0% +son konu or his wife mut so he's going +to these different he's processed + + align:start position:0% +to these different he's processed + + + align:start position:0% +to these different he's processed +through these different Temple complexes + + align:start position:0% +through these different Temple complexes + + + align:start position:0% +through these different Temple complexes +and eventually he ends up back in + + align:start position:0% +and eventually he ends up back in + + + align:start position:0% +and eventually he ends up back in +another Sacred Space so uh what happens + + align:start position:0% +another Sacred Space so uh what happens + + + align:start position:0% +another Sacred Space so uh what happens +is that the people of um the people in + + align:start position:0% +is that the people of um the people in + + + align:start position:0% +is that the people of um the people in +the procession actually pick up the bark + + align:start position:0% +the procession actually pick up the bark + + + align:start position:0% +the procession actually pick up the bark +so this is an example here of the bark + + align:start position:0% +so this is an example here of the bark + + + align:start position:0% +so this is an example here of the bark +and then the image of the godhead is + + align:start position:0% +and then the image of the godhead is + + + align:start position:0% +and then the image of the godhead is +inside and thus the belief is that the + + align:start position:0% +inside and thus the belief is that the + + + align:start position:0% +inside and thus the belief is that the +God is there he's present there they've + + align:start position:0% +God is there he's present there they've + + + align:start position:0% +God is there he's present there they've +removed him from the inner sanctum of + + align:start position:0% +removed him from the inner sanctum of + + + align:start position:0% +removed him from the inner sanctum of +the temple and he's processed through + + align:start position:0% +the temple and he's processed through + + + align:start position:0% +the temple and he's processed through +space and so here all the celebrations + + align:start position:0% +space and so here all the celebrations + + + align:start position:0% +space and so here all the celebrations +they people are bringing cattle with + + align:start position:0% +they people are bringing cattle with + + + align:start position:0% +they people are bringing cattle with +them and here we can see play people + + align:start position:0% +them and here we can see play people + + + align:start position:0% +them and here we can see play people +playing a loot likee object so there's + + align:start position:0% +playing a loot likee object so there's + + + align:start position:0% +playing a loot likee object so there's +and this is an artist rendering of the + + align:start position:0% +and this is an artist rendering of the + + + align:start position:0% +and this is an artist rendering of the +of a large bark on the River on the Nile + + align:start position:0% +of a large bark on the River on the Nile + + + align:start position:0% +of a large bark on the River on the Nile +and then within it you can see the small + + align:start position:0% +and then within it you can see the small + + + align:start position:0% +and then within it you can see the small +bark with the image of the god um God + + align:start position:0% +bark with the image of the god um God + + + align:start position:0% +bark with the image of the god um God +within it so and it's very interesting + + align:start position:0% +within it so and it's very interesting + + + align:start position:0% +within it so and it's very interesting +I'd like to just very quickly briefly + + align:start position:0% +I'd like to just very quickly briefly + + + align:start position:0% +I'd like to just very quickly briefly +read um Herodotus saw one of these + + align:start position:0% +read um Herodotus saw one of these + + + align:start position:0% +read um Herodotus saw one of these +processions at one point um our friend + + align:start position:0% +processions at one point um our friend + + + align:start position:0% +processions at one point um our friend +the Greek historian uh and he describes + + align:start position:0% +the Greek historian uh and he describes + + + align:start position:0% +the Greek historian uh and he describes +it very interesting he says the + + align:start position:0% +it very interesting he says the + + + align:start position:0% +it very interesting he says the +Egyptians hold their solemn assemblies + + align:start position:0% +Egyptians hold their solemn assemblies + + + align:start position:0% +Egyptians hold their solemn assemblies +not once in the year but often now when + + align:start position:0% +not once in the year but often now when + + + align:start position:0% +not once in the year but often now when +they are coming to the city of bubastis + + align:start position:0% +they are coming to the city of bubastis + + + align:start position:0% +they are coming to the city of bubastis +they do as follows they sail men and + + align:start position:0% +they do as follows they sail men and + + + align:start position:0% +they do as follows they sail men and +women together in a great multitude of + + align:start position:0% +women together in a great multitude of + + + align:start position:0% +women together in a great multitude of +each sex in every boat and some of the + + align:start position:0% +each sex in every boat and some of the + + + align:start position:0% +each sex in every boat and some of the +men have rattles and rattle with them + + align:start position:0% +men have rattles and rattle with them + + + align:start position:0% +men have rattles and rattle with them +while some of the men play the flute + + align:start position:0% +while some of the men play the flute + + + align:start position:0% +while some of the men play the flute +during the whole time of the voyage and + + align:start position:0% +during the whole time of the voyage and + + + align:start position:0% +during the whole time of the voyage and +the rest both men and women sing and + + align:start position:0% +the rest both men and women sing and + + + align:start position:0% +the rest both men and women sing and +clap their hands and when as and when as + + align:start position:0% +clap their hands and when as and when as + + + align:start position:0% +clap their hands and when as and when as +they sail they come opposite to any City + + align:start position:0% +they sail they come opposite to any City + + + align:start position:0% +they sail they come opposite to any City +on the way they bring the boat to land + + align:start position:0% +on the way they bring the boat to land + + + align:start position:0% +on the way they bring the boat to land +and some of the women continue to do as + + align:start position:0% +and some of the women continue to do as + + + align:start position:0% +and some of the women continue to do as +I have said others cry allow and Jer at + + align:start position:0% +I have said others cry allow and Jer at + + + align:start position:0% +I have said others cry allow and Jer at +the women in the city some dance and + + align:start position:0% +the women in the city some dance and + + + align:start position:0% +the women in the city some dance and +some stand up and pull their pull up + + align:start position:0% +some stand up and pull their pull up + + + align:start position:0% +some stand up and pull their pull up +their garments this they do by every + + align:start position:0% +their garments this they do by every + + + align:start position:0% +their garments this they do by every +city along the riverbank and when they + + align:start position:0% +city along the riverbank and when they + + + align:start position:0% +city along the riverbank and when they +come to basas they hold Festival SE + + align:start position:0% +come to basas they hold Festival SE + + + align:start position:0% +come to basas they hold Festival SE +celebrating great sacrifices and more + + align:start position:0% +celebrating great sacrifices and more + + + align:start position:0% +celebrating great sacrifices and more +wine of grapes is consumed upon that + + align:start position:0% +wine of grapes is consumed upon that + + + align:start position:0% +wine of grapes is consumed upon that +Festival than then during the whole rest + + align:start position:0% +Festival than then during the whole rest + + + align:start position:0% +Festival than then during the whole rest +of the year so um you can see here that + + align:start position:0% +of the year so um you can see here that + + + align:start position:0% +of the year so um you can see here that +these and and um these individuals in + + align:start position:0% +these and and um these individuals in + + + align:start position:0% +these and and um these individuals in +these reliefs that are out of the Luxor + + align:start position:0% +these reliefs that are out of the Luxor + + + align:start position:0% +these reliefs that are out of the Luxor +Temple and the and the carac these are + + align:start position:0% +Temple and the and the carac these are + + + align:start position:0% +Temple and the and the carac these are +just a variety of reliefs kind of + + align:start position:0% +just a variety of reliefs kind of + + + align:start position:0% +just a variety of reliefs kind of +showing kind of outlining this this + + align:start position:0% +showing kind of outlining this this + + + align:start position:0% +showing kind of outlining this this +processional activity and these priests + + align:start position:0% +processional activity and these priests + + + align:start position:0% +processional activity and these priests +are called wob priests um and + + align:start position:0% +are called wob priests um and + + + align:start position:0% +are called wob priests um and +uh the + + align:start position:0% + + + + align:start position:0% + +um excuse me the the next tradition that + + align:start position:0% +um excuse me the the next tradition that + + + align:start position:0% +um excuse me the the next tradition that +uh we would like to we're going to take + + align:start position:0% +uh we would like to we're going to take + + + align:start position:0% +uh we would like to we're going to take +a look at here um differs to quite some + + align:start position:0% +a look at here um differs to quite some + + + align:start position:0% +a look at here um differs to quite some +extent um and this is Buddhism now we've + + align:start position:0% +extent um and this is Buddhism now we've + + + align:start position:0% +extent um and this is Buddhism now we've +already talked about the Buddha and his + + align:start position:0% +already talked about the Buddha and his + + + align:start position:0% +already talked about the Buddha and his +his um + + align:start position:0% +his um + + + align:start position:0% +his um +his Origins and and the kind of origins + + align:start position:0% +his Origins and and the kind of origins + + + align:start position:0% +his Origins and and the kind of origins +of Buddhism and the the fact that it uh + + align:start position:0% +of Buddhism and the the fact that it uh + + + align:start position:0% +of Buddhism and the the fact that it uh +begins in India and it kind of spreads + + align:start position:0% +begins in India and it kind of spreads + + + align:start position:0% +begins in India and it kind of spreads +uh throughout Asia um and so we've + + align:start position:0% +uh throughout Asia um and so we've + + + align:start position:0% +uh throughout Asia um and so we've +covered that but what I'd like to come + + align:start position:0% +covered that but what I'd like to come + + + align:start position:0% +covered that but what I'd like to come +back to now is this notion of pilgrimage + + align:start position:0% +back to now is this notion of pilgrimage + + + align:start position:0% +back to now is this notion of pilgrimage +with Buddhism and + + align:start position:0% + + + + align:start position:0% + +um the um you know as we've talked about + + align:start position:0% +um the um you know as we've talked about + + + align:start position:0% +um the um you know as we've talked about +before we've talked about the eight-fold + + align:start position:0% +before we've talked about the eight-fold + + + align:start position:0% +before we've talked about the eight-fold +path and what it means to you know + + align:start position:0% +path and what it means to you know + + + align:start position:0% +path and what it means to you know +Enlightenment we've discussed + + align:start position:0% +Enlightenment we've discussed + + + align:start position:0% +Enlightenment we've discussed +uh the ideas of the stupa and what those + + align:start position:0% +uh the ideas of the stupa and what those + + + align:start position:0% +uh the ideas of the stupa and what those +are um and the variety of traditions + + align:start position:0% +are um and the variety of traditions + + + align:start position:0% +are um and the variety of traditions +obviously here this is an example from + + align:start position:0% +obviously here this is an example from + + + align:start position:0% +obviously here this is an example from +Thailand of of a Buddhist uh procession + + align:start position:0% +Thailand of of a Buddhist uh procession + + + align:start position:0% +Thailand of of a Buddhist uh procession +this is also an an example um of a um a + + align:start position:0% +this is also an an example um of a um a + + + align:start position:0% +this is also an an example um of a um a +Buddhist Shrine in Myanmar and this this + + align:start position:0% +Buddhist Shrine in Myanmar and this this + + + align:start position:0% +Buddhist Shrine in Myanmar and this this +I just show this slide basically because + + align:start position:0% +I just show this slide basically because + + + align:start position:0% +I just show this slide basically because +um there's this notion in Buddhism that + + align:start position:0% +um there's this notion in Buddhism that + + + align:start position:0% +um there's this notion in Buddhism that +I've come across of + + align:start position:0% +I've come across of + + + align:start position:0% +I've come across of +um the kind of difficulty associated + + align:start position:0% +um the kind of difficulty associated + + + align:start position:0% +um the kind of difficulty associated +with the path + + align:start position:0% +with the path + + + align:start position:0% +with the path +is warrants more and there's like an + + align:start position:0% +is warrants more and there's like an + + + align:start position:0% +is warrants more and there's like an +accumulation of Merit there's this a + + align:start position:0% +accumulation of Merit there's this a + + + align:start position:0% +accumulation of Merit there's this a +kind of accum the harder the path the + + align:start position:0% +kind of accum the harder the path the + + + align:start position:0% +kind of accum the harder the path the +more the struggle the greater the + + align:start position:0% +more the struggle the greater the + + + align:start position:0% +more the struggle the greater the +attainment of some kind of spiritual or + + align:start position:0% +attainment of some kind of spiritual or + + + align:start position:0% +attainment of some kind of spiritual or +um kind of Merit I guess is for lack of + + align:start position:0% +um kind of Merit I guess is for lack of + + + align:start position:0% +um kind of Merit I guess is for lack of +a better term um but really I'd like to + + align:start position:0% +a better term um but really I'd like to + + + align:start position:0% +a better term um but really I'd like to +point us to the uh the scriptural basis + + align:start position:0% +point us to the uh the scriptural basis + + + align:start position:0% +point us to the uh the scriptural basis +and motivation um within Buddhism um and + + align:start position:0% +and motivation um within Buddhism um and + + + align:start position:0% +and motivation um within Buddhism um and +here the Buddha is uh + + align:start position:0% +here the Buddha is uh + + + align:start position:0% +here the Buddha is uh +um believed to have said to called for + + align:start position:0% +um believed to have said to called for + + + align:start position:0% +um believed to have said to called for +the P the pilgrimage to four main sites + + align:start position:0% +the P the pilgrimage to four main sites + + + align:start position:0% +the P the pilgrimage to four main sites +so he says um here the tagata uh which + + align:start position:0% +so he says um here the tagata uh which + + + align:start position:0% +so he says um here the tagata uh which +is um he's referring to himself the + + align:start position:0% +is um he's referring to himself the + + + align:start position:0% +is um he's referring to himself the +perfected one he says that the first is + + align:start position:0% +perfected one he says that the first is + + + align:start position:0% +perfected one he says that the first is +where he was born the second is where he + + align:start position:0% +where he was born the second is where he + + + align:start position:0% +where he was born the second is where he +attained Supreme + + align:start position:0% +attained Supreme + + + align:start position:0% +attained Supreme +Enlightenment uh the fourth is where the + + align:start position:0% +Enlightenment uh the fourth is where the + + + align:start position:0% +Enlightenment uh the fourth is where the +third is where he set in the wheel of + + align:start position:0% +third is where he set in the wheel of + + + align:start position:0% +third is where he set in the wheel of +Dharma the where he gave his first + + align:start position:0% +Dharma the where he gave his first + + + align:start position:0% +Dharma the where he gave his first +lecture and then the fourth is where he + + align:start position:0% +lecture and then the fourth is where he + + + align:start position:0% +lecture and then the fourth is where he +um passed away into Nirvana where he + + align:start position:0% +um passed away into Nirvana where he + + + align:start position:0% +um passed away into Nirvana where he +died and so these uh to to to kind of + + align:start position:0% +died and so these uh to to to kind of + + + align:start position:0% +died and so these uh to to to kind of +illustrate some of the the themes around + + align:start position:0% +illustrate some of the the themes around + + + align:start position:0% +illustrate some of the the themes around +Buddhist pilgrimage that sort of begin + + align:start position:0% +Buddhist pilgrimage that sort of begin + + + align:start position:0% +Buddhist pilgrimage that sort of begin +to Define it um are that the this early + + align:start position:0% +to Define it um are that the this early + + + align:start position:0% +to Define it um are that the this early +notion of Buddhist pilgrimage is based + + align:start position:0% +notion of Buddhist pilgrimage is based + + + align:start position:0% +notion of Buddhist pilgrimage is based +around the Buddha life so many people + + align:start position:0% +around the Buddha life so many people + + + align:start position:0% +around the Buddha life so many people +will travel to these different sacred + + align:start position:0% +will travel to these different sacred + + + align:start position:0% +will travel to these different sacred +places uh in in the order in which they + + align:start position:0% +places uh in in the order in which they + + + align:start position:0% +places uh in in the order in which they +happened not necessarily from what I've + + align:start position:0% +happened not necessarily from what I've + + + align:start position:0% +happened not necessarily from what I've +come across but it is sometimes uh if + + align:start position:0% +come across but it is sometimes uh if + + + align:start position:0% +come across but it is sometimes uh if +somebody's going to do the entire route + + align:start position:0% +somebody's going to do the entire route + + + align:start position:0% +somebody's going to do the entire route +they'll go the they'll go to everyone in + + align:start position:0% +they'll go the they'll go to everyone in + + + align:start position:0% +they'll go the they'll go to everyone in +that order uh and so you're sort of + + align:start position:0% +that order uh and so you're sort of + + + align:start position:0% +that order uh and so you're sort of +traveling in this path of the Buddha of + + align:start position:0% +traveling in this path of the Buddha of + + + align:start position:0% +traveling in this path of the Buddha of +a of a holy individual you're kind of + + align:start position:0% +a of a holy individual you're kind of + + + align:start position:0% +a of a holy individual you're kind of +recreating their you're re trying to + + align:start position:0% +recreating their you're re trying to + + + align:start position:0% +recreating their you're re trying to +re-experience their life essentially um + + align:start position:0% +re-experience their life essentially um + + + align:start position:0% +re-experience their life essentially um +and there are relics Within These + + align:start position:0% +and there are relics Within These + + + align:start position:0% +and there are relics Within These +different places so um the presence or + + align:start position:0% +different places so um the presence or + + + align:start position:0% +different places so um the presence or +the sacred throughout the land is sort + + align:start position:0% +the sacred throughout the land is sort + + + align:start position:0% +the sacred throughout the land is sort +of dispersed throughout the + + align:start position:0% +of dispersed throughout the + + + align:start position:0% +of dispersed throughout the +landscape um and circumambulation is a + + align:start position:0% +landscape um and circumambulation is a + + + align:start position:0% +landscape um and circumambulation is a +big is a key feature to Buddhism there's + + align:start position:0% +big is a key feature to Buddhism there's + + + align:start position:0% +big is a key feature to Buddhism there's +um a lot of circum ulation as a kind of + + align:start position:0% +um a lot of circum ulation as a kind of + + + align:start position:0% +um a lot of circum ulation as a kind of +a spiritual um + + align:start position:0% +a spiritual um + + + align:start position:0% +a spiritual um +um as a sort of spiritual reflection uh + + align:start position:0% +um as a sort of spiritual reflection uh + + + align:start position:0% +um as a sort of spiritual reflection uh +and also the accumulation of Merit for + + align:start position:0% +and also the accumulation of Merit for + + + align:start position:0% +and also the accumulation of Merit for +long and difficult Journeys which I've + + align:start position:0% +long and difficult Journeys which I've + + + align:start position:0% +long and difficult Journeys which I've +already briefly discussed um the four + + align:start position:0% +already briefly discussed um the four + + + align:start position:0% +already briefly discussed um the four +main locations uh + + align:start position:0% + + + + align:start position:0% + +oops uh are lumini um sarth bodgaya and + + align:start position:0% +oops uh are lumini um sarth bodgaya and + + + align:start position:0% +oops uh are lumini um sarth bodgaya and +um kushnar which um are the sites that + + align:start position:0% +um kushnar which um are the sites that + + + align:start position:0% +um kushnar which um are the sites that +we'll be looking at um specifically but + + align:start position:0% +we'll be looking at um specifically but + + + align:start position:0% +we'll be looking at um specifically but +before we get into that again I would + + align:start position:0% +before we get into that again I would + + + align:start position:0% +before we get into that again I would +like to kind of I'm trying to you know + + align:start position:0% +like to kind of I'm trying to you know + + + align:start position:0% +like to kind of I'm trying to you know +come back to our notion of the Sacred + + align:start position:0% +come back to our notion of the Sacred + + + align:start position:0% +come back to our notion of the Sacred +and the profane with each of these + + align:start position:0% +and the profane with each of these + + + align:start position:0% +and the profane with each of these +examples and this is just another + + align:start position:0% +examples and this is just another + + + align:start position:0% +examples and this is just another +diagram kind of trying to outline the + + align:start position:0% +diagram kind of trying to outline the + + + align:start position:0% +diagram kind of trying to outline the +way in which you know one way at least + + align:start position:0% +way in which you know one way at least + + + align:start position:0% +way in which you know one way at least +in which we can + + align:start position:0% +in which we can + + + align:start position:0% +in which we can +view um an understanding of the Sacred + + align:start position:0% +view um an understanding of the Sacred + + + align:start position:0% +view um an understanding of the Sacred +and profane and early Buddhist + + align:start position:0% +and profane and early Buddhist + + + align:start position:0% +and profane and early Buddhist +pilgrimage and so here again we have + + align:start position:0% +pilgrimage and so here again we have + + + align:start position:0% +pilgrimage and so here again we have +these kind of sacred nodes and we passed + + align:start position:0% +these kind of sacred nodes and we passed + + + align:start position:0% +these kind of sacred nodes and we passed +through them through the profane to get + + align:start position:0% +through them through the profane to get + + + align:start position:0% +through them through the profane to get +to get to each one and and and like I + + align:start position:0% +to get to each one and and and like I + + + align:start position:0% +to get to each one and and and like I +said earlier there's not a a um a + + align:start position:0% +said earlier there's not a a um a + + + align:start position:0% +said earlier there's not a a um a +specific manner in which that happens + + align:start position:0% +specific manner in which that happens + + + align:start position:0% +specific manner in which that happens +but this becomes more complicated when + + align:start position:0% +but this becomes more complicated when + + + align:start position:0% +but this becomes more complicated when +um Buddha's relics are distributed into + + align:start position:0% +um Buddha's relics are distributed into + + + align:start position:0% +um Buddha's relics are distributed into +over 880,000 places and um this it + + align:start position:0% +over 880,000 places and um this it + + + align:start position:0% +over 880,000 places and um this it +becomes a little bit more complicated + + align:start position:0% +becomes a little bit more complicated + + + align:start position:0% +becomes a little bit more complicated +later but for now we're kind of trying + + align:start position:0% +later but for now we're kind of trying + + + align:start position:0% +later but for now we're kind of trying +to focus on the early uh aspects the + + align:start position:0% +to focus on the early uh aspects the + + + align:start position:0% +to focus on the early uh aspects the +um the first um this is the birthplace + + align:start position:0% +um the first um this is the birthplace + + + align:start position:0% +um the first um this is the birthplace +of the Buddha uh in lumini which is + + align:start position:0% +of the Buddha uh in lumini which is + + + align:start position:0% +of the Buddha uh in lumini which is +present day Nepal uh he was born in 563 + + align:start position:0% +present day Nepal uh he was born in 563 + + + align:start position:0% +present day Nepal uh he was born in 563 +approximately and um located in the + + align:start position:0% +approximately and um located in the + + + align:start position:0% +approximately and um located in the +foothills of the Himalayas and uh what + + align:start position:0% +foothills of the Himalayas and uh what + + + align:start position:0% +foothills of the Himalayas and uh what +we see here on the left is an asokan + + align:start position:0% +we see here on the left is an asokan + + + align:start position:0% +we see here on the left is an asokan +pillar uh which marks the birthplace of + + align:start position:0% +pillar uh which marks the birthplace of + + + align:start position:0% +pillar uh which marks the birthplace of +the Buddha and you can see you can see + + align:start position:0% +the Buddha and you can see you can see + + + align:start position:0% +the Buddha and you can see you can see +the uh monks and other pilgrims kind of + + align:start position:0% +the uh monks and other pilgrims kind of + + + align:start position:0% +the uh monks and other pilgrims kind of +circum ulating around it uh and then on + + align:start position:0% +circum ulating around it uh and then on + + + align:start position:0% +circum ulating around it uh and then on +the right we have a reflecting pool with + + align:start position:0% +the right we have a reflecting pool with + + + align:start position:0% +the right we have a reflecting pool with +a a more recent + + align:start position:0% +a a more recent + + + align:start position:0% +a a more recent +Temple this second example is this is + + align:start position:0% +Temple this second example is this is + + + align:start position:0% +Temple this second example is this is +where the Buddha delivered his first + + align:start position:0% +where the Buddha delivered his first + + + align:start position:0% +where the Buddha delivered his first +meeting where people come to pilgrimage + + align:start position:0% +meeting where people come to pilgrimage + + + align:start position:0% +meeting where people come to pilgrimage +they also circum ulate this stupa this + + align:start position:0% +they also circum ulate this stupa this + + + align:start position:0% +they also circum ulate this stupa this +is the dhek stupa uh again built by + + align:start position:0% +is the dhek stupa uh again built by + + + align:start position:0% +is the dhek stupa uh again built by +Asoka uh in the 3D Century so + + align:start position:0% +Asoka uh in the 3D Century so + + + align:start position:0% +Asoka uh in the 3D Century so +essentially the great emperor Oka came + + align:start position:0% +essentially the great emperor Oka came + + + align:start position:0% +essentially the great emperor Oka came +and sort of created all these built all + + align:start position:0% +and sort of created all these built all + + + align:start position:0% +and sort of created all these built all +these monuments to commemorate uh the + + align:start position:0% +these monuments to commemorate uh the + + + align:start position:0% +these monuments to commemorate uh the +Buddha and so + + align:start position:0% +Buddha and so + + + align:start position:0% +Buddha and so +um the third place is one of the most + + align:start position:0% +um the third place is one of the most + + + align:start position:0% +um the third place is one of the most +holy it's where he uh achieved + + align:start position:0% +holy it's where he uh achieved + + + align:start position:0% +holy it's where he uh achieved +Enlightenment uh next under the Bodhi + + align:start position:0% +Enlightenment uh next under the Bodhi + + + align:start position:0% +Enlightenment uh next under the Bodhi +Tree uh which is what this Temple the + + align:start position:0% +Tree uh which is what this Temple the + + + align:start position:0% +Tree uh which is what this Temple the +bodaya the um at bodgaya the mahabodhi + + align:start position:0% +bodaya the um at bodgaya the mahabodhi + + + align:start position:0% +bodaya the um at bodgaya the mahabodhi +temple uh commemorates this is a brick + + align:start position:0% +temple uh commemorates this is a brick + + + align:start position:0% +temple uh commemorates this is a brick +structure um and it + + align:start position:0% +structure um and it + + + align:start position:0% +structure um and it +is approximately 180 ft tall and um the + + align:start position:0% +is approximately 180 ft tall and um the + + + align:start position:0% +is approximately 180 ft tall and um the +brick work um depicts scenes from the + + align:start position:0% +brick work um depicts scenes from the + + + align:start position:0% +brick work um depicts scenes from the +life of the Buddha and this is where he + + align:start position:0% +life of the Buddha and this is where he + + + align:start position:0% +life of the Buddha and this is where he +really is transformed from Prince gatama + + align:start position:0% +really is transformed from Prince gatama + + + align:start position:0% +really is transformed from Prince gatama +to the Lord Buddha um so this is an + + align:start position:0% +to the Lord Buddha um so this is an + + + align:start position:0% +to the Lord Buddha um so this is an +extremely important um location for + + align:start position:0% +extremely important um location for + + + align:start position:0% +extremely important um location for +pilgrims this is a footprint sculpture + + align:start position:0% +pilgrims this is a footprint sculpture + + + align:start position:0% +pilgrims this is a footprint sculpture +of the Buddhist feet uh and also a + + align:start position:0% +of the Buddhist feet uh and also a + + + align:start position:0% +of the Buddhist feet uh and also a +pilgrim inside commemorating uh the life + + align:start position:0% +pilgrim inside commemorating uh the life + + + align:start position:0% +pilgrim inside commemorating uh the life +of the + + align:start position:0% +of the + + + align:start position:0% +of the +Buddha the last place is the is + + align:start position:0% +Buddha the last place is the is + + + align:start position:0% +Buddha the last place is the is +kushinagar which is where the Buddha + + align:start position:0% +kushinagar which is where the Buddha + + + align:start position:0% +kushinagar which is where the Buddha +passed away um on the bottom we see a + + align:start position:0% +passed away um on the bottom we see a + + + align:start position:0% +passed away um on the bottom we see a +six meter long statue that was excavated + + align:start position:0% +six meter long statue that was excavated + + + align:start position:0% +six meter long statue that was excavated +in the 19th century um and um the + + align:start position:0% +in the 19th century um and um the + + + align:start position:0% +in the 19th century um and um the +Buddhist remains were at one point + + align:start position:0% +Buddhist remains were at one point + + + align:start position:0% +Buddhist remains were at one point +deposited here under the Nirvana stupa + + align:start position:0% +deposited here under the Nirvana stupa + + + align:start position:0% +deposited here under the Nirvana stupa +um and um basically this is where he + + align:start position:0% +um and um basically this is where he + + + align:start position:0% +um and um basically this is where he +performed his last sermon and + + align:start position:0% +performed his last sermon and + + + align:start position:0% +performed his last sermon and +subsequently passed + + align:start position:0% +subsequently passed + + + align:start position:0% +subsequently passed +away + + align:start position:0% +away + + + align:start position:0% +away +so as we move forward we we're going to + + align:start position:0% +so as we move forward we we're going to + + + align:start position:0% +so as we move forward we we're going to +take a look at um the tradition of Islam + + align:start position:0% +take a look at um the tradition of Islam + + + align:start position:0% +take a look at um the tradition of Islam +and pilgrimage which I sort of argue + + align:start position:0% +and pilgrimage which I sort of argue + + + align:start position:0% +and pilgrimage which I sort of argue +here in my title is consolidation and + + align:start position:0% +here in my title is consolidation and + + + align:start position:0% +here in my title is consolidation and +globalization of pilgrimage + + align:start position:0% +globalization of pilgrimage + + + align:start position:0% +globalization of pilgrimage +and um I say that + + align:start position:0% +and um I say that + + + align:start position:0% +and um I say that +because + + align:start position:0% +because + + + align:start position:0% +because +um in Islam no matter where you are + + align:start position:0% +um in Islam no matter where you are + + + align:start position:0% +um in Islam no matter where you are +you're essentially required to go to + + align:start position:0% +you're essentially required to go to + + + align:start position:0% +you're essentially required to go to +Mecca to make the pilgrimage or the Hajj + + align:start position:0% +Mecca to make the pilgrimage or the Hajj + + + align:start position:0% +Mecca to make the pilgrimage or the Hajj +um and this obviously entails can can + + align:start position:0% +um and this obviously entails can can + + + align:start position:0% +um and this obviously entails can can +entail quite a bit of um of travel and + + align:start position:0% +entail quite a bit of um of travel and + + + align:start position:0% +entail quite a bit of um of travel and +so uh similar to Buddhism uh Islam is + + align:start position:0% +so uh similar to Buddhism uh Islam is + + + align:start position:0% +so uh similar to Buddhism uh Islam is +scripturally based it's in the Quran + + align:start position:0% +scripturally based it's in the Quran + + + align:start position:0% +scripturally based it's in the Quran +it's also the fifth pillar of Islam + + align:start position:0% +it's also the fifth pillar of Islam + + + align:start position:0% +it's also the fifth pillar of Islam +which uh requires mus all Muslims to go + + align:start position:0% +which uh requires mus all Muslims to go + + + align:start position:0% +which uh requires mus all Muslims to go +make the um Hajj and so here we just + + align:start position:0% +make the um Hajj and so here we just + + + align:start position:0% +make the um Hajj and so here we just +have a very basic very uh quick slide um + + align:start position:0% +have a very basic very uh quick slide um + + + align:start position:0% +have a very basic very uh quick slide um +to slide 38 to indicate um to show the + + align:start position:0% +to slide 38 to indicate um to show the + + + align:start position:0% +to slide 38 to indicate um to show the +significance of of the kabah in Mecca + + align:start position:0% +significance of of the kabah in Mecca + + + align:start position:0% +significance of of the kabah in Mecca +I'm going to get back to this in a + + align:start position:0% +I'm going to get back to this in a + + + align:start position:0% +I'm going to get back to this in a +minute here but what's occurring is + + align:start position:0% +minute here but what's occurring is + + + align:start position:0% +minute here but what's occurring is +circum ulation again we can see with the + + align:start position:0% +circum ulation again we can see with the + + + align:start position:0% +circum ulation again we can see with the +the kind of long exposure f photograph + + align:start position:0% +the kind of long exposure f photograph + + + align:start position:0% +the kind of long exposure f photograph +here of the movement around the + + align:start position:0% +here of the movement around the + + + align:start position:0% +here of the movement around the +Kabab um and so my diagram is naturally + + align:start position:0% +Kabab um and so my diagram is naturally + + + align:start position:0% +Kabab um and so my diagram is naturally +one that is very + + align:start position:0% +one that is very + + + align:start position:0% +one that is very +um very much + + align:start position:0% +um very much + + + align:start position:0% +um very much +about um congregating into one specific + + align:start position:0% +about um congregating into one specific + + + align:start position:0% +about um congregating into one specific +sacred holy place right so it's a very + + align:start position:0% +sacred holy place right so it's a very + + + align:start position:0% +sacred holy place right so it's a very +basic diagram that tries to just at + + align:start position:0% +basic diagram that tries to just at + + + align:start position:0% +basic diagram that tries to just at +least articulate this idea that um we're + + align:start position:0% +least articulate this idea that um we're + + + align:start position:0% +least articulate this idea that um we're +all coming from these different profane + + align:start position:0% +all coming from these different profane + + + align:start position:0% +all coming from these different profane +spaces but we all when we come together + + align:start position:0% +spaces but we all when we come together + + + align:start position:0% +spaces but we all when we come together +uh in Mecca this is the sacred it's the + + align:start position:0% +uh in Mecca this is the sacred it's the + + + align:start position:0% +uh in Mecca this is the sacred it's the +the moment of the Sacred and so just + + align:start position:0% +the moment of the Sacred and so just + + + align:start position:0% +the moment of the Sacred and so just +some very basic uh + + align:start position:0% +some very basic uh + + + align:start position:0% +some very basic uh +characteristics um I don't want to get + + align:start position:0% +characteristics um I don't want to get + + + align:start position:0% +characteristics um I don't want to get +into these too much but um circum + + align:start position:0% +into these too much but um circum + + + align:start position:0% +into these too much but um circum +ulation again but one of the biggest + + align:start position:0% +ulation again but one of the biggest + + + align:start position:0% +ulation again but one of the biggest +things I'd like to uh discuss here is + + align:start position:0% +things I'd like to uh discuss here is + + + align:start position:0% +things I'd like to uh discuss here is +this notion of communitas again um which + + align:start position:0% +this notion of communitas again um which + + + align:start position:0% +this notion of communitas again um which +really the hodj takes place once a year + + align:start position:0% +really the hodj takes place once a year + + + align:start position:0% +really the hodj takes place once a year +and you it is performed communally so + + align:start position:0% +and you it is performed communally so + + + align:start position:0% +and you it is performed communally so +this is a very big aspect to it I mean + + align:start position:0% +this is a very big aspect to it I mean + + + align:start position:0% +this is a very big aspect to it I mean +it's not to say that you can't go on the + + align:start position:0% +it's not to say that you can't go on the + + + align:start position:0% +it's not to say that you can't go on the +hjj the rest of the year but but it's uh + + align:start position:0% +hjj the rest of the year but but it's uh + + + align:start position:0% +hjj the rest of the year but but it's uh +still required that you make the Hajj as + + align:start position:0% +still required that you make the Hajj as + + + align:start position:0% +still required that you make the Hajj as +a as a communal thing um the official + + align:start position:0% +a as a communal thing um the official + + + align:start position:0% +a as a communal thing um the official +Hajj at once and so um this notion is + + align:start position:0% +Hajj at once and so um this notion is + + + align:start position:0% +Hajj at once and so um this notion is +kind of very important it's very Central + + align:start position:0% +kind of very important it's very Central + + + align:start position:0% +kind of very important it's very Central +to Islam and so the three main locations + + align:start position:0% +to Islam and so the three main locations + + + align:start position:0% +to Islam and so the three main locations +which obviously the most important is + + align:start position:0% +which obviously the most important is + + + align:start position:0% +which obviously the most important is +Mecca uh which is the al- Alam which is + + align:start position:0% +Mecca uh which is the al- Alam which is + + + align:start position:0% +Mecca uh which is the al- Alam which is +the sacred mosque uh which is the the + + align:start position:0% +the sacred mosque uh which is the the + + + align:start position:0% +the sacred mosque uh which is the the +kabah is located within that uh the + + align:start position:0% +kabah is located within that uh the + + + align:start position:0% +kabah is located within that uh the +other two main sites for pilgrimage uh + + align:start position:0% +other two main sites for pilgrimage uh + + + align:start position:0% +other two main sites for pilgrimage uh +that are not required for Islam are are + + align:start position:0% +that are not required for Islam are are + + + align:start position:0% +that are not required for Islam are are +uh Medina where the house of the Prophet + + align:start position:0% +uh Medina where the house of the Prophet + + + align:start position:0% +uh Medina where the house of the Prophet +or the mosque of the Prophet is located + + align:start position:0% +or the mosque of the Prophet is located + + + align:start position:0% +or the mosque of the Prophet is located +and also in Jerusalem uh with the Dome + + align:start position:0% +and also in Jerusalem uh with the Dome + + + align:start position:0% +and also in Jerusalem uh with the Dome +of the Rock this is just a quick a brief + + align:start position:0% +of the Rock this is just a quick a brief + + + align:start position:0% +of the Rock this is just a quick a brief +interesting um map from the 10th Century + + align:start position:0% +interesting um map from the 10th Century + + + align:start position:0% +interesting um map from the 10th Century +by the geographer Al jiani who uh + + align:start position:0% +by the geographer Al jiani who uh + + + align:start position:0% +by the geographer Al jiani who uh +indicates to us the viewer how important + + align:start position:0% +indicates to us the viewer how important + + + align:start position:0% +indicates to us the viewer how important +Mecca is to Islam how it's he literally + + align:start position:0% +Mecca is to Islam how it's he literally + + + align:start position:0% +Mecca is to Islam how it's he literally +is drawing it as the center of the + + align:start position:0% +is drawing it as the center of the + + + align:start position:0% +is drawing it as the center of the +world and this is just a quick graphic I + + align:start position:0% +world and this is just a quick graphic I + + + align:start position:0% +world and this is just a quick graphic I +found + + align:start position:0% +found + + + align:start position:0% +found +uh that uh shows again it's it's + + align:start position:0% +uh that uh shows again it's it's + + + align:start position:0% +uh that uh shows again it's it's +interesting because it my diagram sort + + align:start position:0% +interesting because it my diagram sort + + + align:start position:0% +interesting because it my diagram sort +of abstracts this in a way this is + + align:start position:0% +of abstracts this in a way this is + + + align:start position:0% +of abstracts this in a way this is +literally the amount of uh percentage of + + align:start position:0% +literally the amount of uh percentage of + + + align:start position:0% +literally the amount of uh percentage of +people coming from different locations + + align:start position:0% +people coming from different locations + + + align:start position:0% +people coming from different locations +throughout the world uh coming to the + + align:start position:0% +throughout the world uh coming to the + + + align:start position:0% +throughout the world uh coming to the +Hajj in 1982 so it's just a kind of a + + align:start position:0% +Hajj in 1982 so it's just a kind of a + + + align:start position:0% +Hajj in 1982 so it's just a kind of a +quick graphic to so you can easily see + + align:start position:0% +quick graphic to so you can easily see + + + align:start position:0% +quick graphic to so you can easily see +where where the a great number of + + align:start position:0% +where where the a great number of + + + align:start position:0% +where where the a great number of +Muslims are coming from um it would be + + align:start position:0% +Muslims are coming from um it would be + + + align:start position:0% +Muslims are coming from um it would be +interesting to see a more recent version + + align:start position:0% +interesting to see a more recent version + + + align:start position:0% +interesting to see a more recent version +of that obviously um given the change in + + align:start position:0% +of that obviously um given the change in + + + align:start position:0% +of that obviously um given the change in +population locations um this is an this + + align:start position:0% +population locations um this is an this + + + align:start position:0% +population locations um this is an this +is an abstracted uh plan of the mosque + + align:start position:0% +is an abstracted uh plan of the mosque + + + align:start position:0% +is an abstracted uh plan of the mosque +the alh Haram mosque and um really up to + + align:start position:0% +the alh Haram mosque and um really up to + + + align:start position:0% +the alh Haram mosque and um really up to +the year 785 so it's a very basic mosque + + align:start position:0% +the year 785 so it's a very basic mosque + + + align:start position:0% +the year 785 so it's a very basic mosque +the Cabas in the center and it's + + align:start position:0% +the Cabas in the center and it's + + + align:start position:0% +the Cabas in the center and it's +beginning to acquire this kind of + + align:start position:0% +beginning to acquire this kind of + + + align:start position:0% +beginning to acquire this kind of +colonade uh around + + align:start position:0% +colonade uh around + + + align:start position:0% +colonade uh around +it and so by the 18th century um the + + align:start position:0% +it and so by the 18th century um the + + + align:start position:0% +it and so by the 18th century um the +kabah is here located centrally you can + + align:start position:0% +kabah is here located centrally you can + + + align:start position:0% +kabah is here located centrally you can +see the colonade is pretty well + + align:start position:0% +see the colonade is pretty well + + + align:start position:0% +see the colonade is pretty well +established around it and the city is + + align:start position:0% +established around it and the city is + + + align:start position:0% +established around it and the city is +filling in pretty densely around it as + + align:start position:0% +filling in pretty densely around it as + + + align:start position:0% +filling in pretty densely around it as +well and this is what it is basically + + align:start position:0% +well and this is what it is basically + + + align:start position:0% +well and this is what it is basically +contemporarily uh today as it looks + + align:start position:0% +contemporarily uh today as it looks + + + align:start position:0% +contemporarily uh today as it looks +today and so um this is as it is today + + align:start position:0% +today and so um this is as it is today + + + align:start position:0% +today and so um this is as it is today +during the Hajj um full of + + align:start position:0% +during the Hajj um full of + + + align:start position:0% +during the Hajj um full of +pilgrims again another view and this is + + align:start position:0% +pilgrims again another view and this is + + + align:start position:0% +pilgrims again another view and this is +um this is the kiswa this is the the + + align:start position:0% +um this is the kiswa this is the the + + + align:start position:0% +um this is the kiswa this is the the +black silk cloth that covers that this + + align:start position:0% +black silk cloth that covers that this + + + align:start position:0% +black silk cloth that covers that this +site is very sacred to Islam for a + + align:start position:0% +site is very sacred to Islam for a + + + align:start position:0% +site is very sacred to Islam for a +number of reasons but basic very quickly + + align:start position:0% +number of reasons but basic very quickly + + + align:start position:0% +number of reasons but basic very quickly +and basically um ibraim or Abraham is + + align:start position:0% +and basically um ibraim or Abraham is + + + align:start position:0% +and basically um ibraim or Abraham is +said to have uh left his wife and son um + + align:start position:0% +said to have uh left his wife and son um + + + align:start position:0% +said to have uh left his wife and son um +Ismael here very briefly while he went + + align:start position:0% +Ismael here very briefly while he went + + + align:start position:0% +Ismael here very briefly while he went +to Palestine and um Ismael discovered or + + align:start position:0% +to Palestine and um Ismael discovered or + + + align:start position:0% +to Palestine and um Ismael discovered or +you know it's a long story but he + + align:start position:0% +you know it's a long story but he + + + align:start position:0% +you know it's a long story but he +discovered a spring here this holy well + + align:start position:0% +discovered a spring here this holy well + + + align:start position:0% +discovered a spring here this holy well +of Zam Zam and so um not only is that + + align:start position:0% +of Zam Zam and so um not only is that + + + align:start position:0% +of Zam Zam and so um not only is that +significant and then obviously um well + + align:start position:0% +significant and then obviously um well + + + align:start position:0% +significant and then obviously um well +not obviously but Allah instructed + + align:start position:0% +not obviously but Allah instructed + + + align:start position:0% +not obviously but Allah instructed +Ibrahim to create a to build this + + align:start position:0% +Ibrahim to create a to build this + + + align:start position:0% +Ibrahim to create a to build this +structure to commemorate him and so uh + + align:start position:0% +structure to commemorate him and so uh + + + align:start position:0% +structure to commemorate him and so uh +he did that and he this is also uh + + align:start position:0% +he did that and he this is also uh + + + align:start position:0% +he did that and he this is also uh +supposedly the tomb of Abraham as well + + align:start position:0% +supposedly the tomb of Abraham as well + + + align:start position:0% +supposedly the tomb of Abraham as well +so there and there are all kinds of + + align:start position:0% +so there and there are all kinds of + + + align:start position:0% +so there and there are all kinds of +other um significant associations with + + align:start position:0% +other um significant associations with + + + align:start position:0% +other um significant associations with +this um and so here this is just to + + align:start position:0% +this um and so here this is just to + + + align:start position:0% +this um and so here this is just to +quickly show um some pilgrims performing + + align:start position:0% +quickly show um some pilgrims performing + + + align:start position:0% +quickly show um some pilgrims performing +the Hodge where they're coming from and + + align:start position:0% +the Hodge where they're coming from and + + + align:start position:0% +the Hodge where they're coming from and +where they're going and this is + + align:start position:0% +where they're going and this is + + + align:start position:0% +where they're going and this is +obviously a very dense packed Street + + align:start position:0% +obviously a very dense packed Street + + + align:start position:0% +obviously a very dense packed Street +here because there's it's a highly + + align:start position:0% +here because there's it's a highly + + + align:start position:0% +here because there's it's a highly +ritualized um highly + + align:start position:0% +ritualized um highly + + + align:start position:0% +ritualized um highly +ritualized um + + align:start position:0% +ritualized um + + + align:start position:0% +ritualized um +um reenactments and circum ulation + + align:start position:0% +um reenactments and circum ulation + + + align:start position:0% +um reenactments and circum ulation +there's all kinds of interesting things + + align:start position:0% +there's all kinds of interesting things + + + align:start position:0% +there's all kinds of interesting things +going on + + align:start position:0% +going on + + + align:start position:0% +going on +here again this is the well this is the + + align:start position:0% +here again this is the well this is the + + + align:start position:0% +here again this is the well this is the +Village um of tents at Mina near nearby + + align:start position:0% +Village um of tents at Mina near nearby + + + align:start position:0% +Village um of tents at Mina near nearby +Mecca so these are all tents and this + + align:start position:0% +Mecca so these are all tents and this + + + align:start position:0% +Mecca so these are all tents and this +can this space can essentially um + + align:start position:0% +can this space can essentially um + + + align:start position:0% +can this space can essentially um +contain about three million pilgrims + + align:start position:0% +contain about three million pilgrims + + + align:start position:0% +contain about three million pilgrims +when they come to perform the + + align:start position:0% +when they come to perform the + + + align:start position:0% +when they come to perform the +Hodge um and then another quick + + align:start position:0% +Hodge um and then another quick + + + align:start position:0% +Hodge um and then another quick +interesting thing I I found is these are + + align:start position:0% +interesting thing I I found is these are + + + align:start position:0% +interesting thing I I found is these are +all uh images of uh house paintings + + align:start position:0% +all uh images of uh house paintings + + + align:start position:0% +all uh images of uh house paintings +displaying evidence of having completed + + align:start position:0% +displaying evidence of having completed + + + align:start position:0% +displaying evidence of having completed +the Hajj so like if you've completed the + + align:start position:0% +the Hajj so like if you've completed the + + + align:start position:0% +the Hajj so like if you've completed the +Hajj you're and you celebrate that + + align:start position:0% +Hajj you're and you celebrate that + + + align:start position:0% +Hajj you're and you celebrate that +by either a painting or you know at + + align:start position:0% +by either a painting or you know at + + + align:start position:0% +by either a painting or you know at +least in these kind of very localized uh + + align:start position:0% +least in these kind of very localized uh + + + align:start position:0% +least in these kind of very localized uh +examples um and so here's a an image + + align:start position:0% +examples um and so here's a an image + + + align:start position:0% +examples um and so here's a an image +here on the left side of the cabal that + + align:start position:0% +here on the left side of the cabal that + + + align:start position:0% +here on the left side of the cabal that +this person has obviously completed the + + align:start position:0% +this person has obviously completed the + + + align:start position:0% +this person has obviously completed the +Hajj and this is uh this is Bak the the + + align:start position:0% +Hajj and this is uh this is Bak the the + + + align:start position:0% +Hajj and this is uh this is Bak the the +horse that Muhammad rode into um Heaven + + align:start position:0% +horse that Muhammad rode into um Heaven + + + align:start position:0% +horse that Muhammad rode into um Heaven +very briefly this is the prophet's + + align:start position:0% +very briefly this is the prophet's + + + align:start position:0% +very briefly this is the prophet's +mosque in Medina as it looks today so + + align:start position:0% +mosque in Medina as it looks today so + + + align:start position:0% +mosque in Medina as it looks today so +again it's full of pilgrims people are + + align:start position:0% +again it's full of pilgrims people are + + + align:start position:0% +again it's full of pilgrims people are +coming here all throughout the year um + + align:start position:0% +coming here all throughout the year um + + + align:start position:0% +coming here all throughout the year um +another Central + + align:start position:0% +another Central + + + align:start position:0% +another Central +um uh Monument to Islam is the Dome of + + align:start position:0% +um uh Monument to Islam is the Dome of + + + align:start position:0% +um uh Monument to Islam is the Dome of +the Rock which we're really not going to + + align:start position:0% +the Rock which we're really not going to + + + align:start position:0% +the Rock which we're really not going to +spend any time with but I just wanted to + + align:start position:0% +spend any time with but I just wanted to + + + align:start position:0% +spend any time with but I just wanted to +show it very briefly this commemorates + + align:start position:0% +show it very briefly this commemorates + + + align:start position:0% +show it very briefly this commemorates +uh several things as well um this is + + align:start position:0% +uh several things as well um this is + + + align:start position:0% +uh several things as well um this is +where supposedly the uh that Muhammad + + align:start position:0% +where supposedly the uh that Muhammad + + + align:start position:0% +where supposedly the uh that Muhammad +rode the horse up into heaven and also + + align:start position:0% +rode the horse up into heaven and also + + + align:start position:0% +rode the horse up into heaven and also +the point where um it's it's thought + + align:start position:0% +the point where um it's it's thought + + + align:start position:0% +the point where um it's it's thought +that uh Abraham was about to + + align:start position:0% +that uh Abraham was about to + + + align:start position:0% +that uh Abraham was about to +um where Abraham was instructed to kill + + align:start position:0% +um where Abraham was instructed to kill + + + align:start position:0% +um where Abraham was instructed to kill +his son Isaac and then obviously the + + align:start position:0% +his son Isaac and then obviously the + + + align:start position:0% +his son Isaac and then obviously the +angels interceded and prevented that so + + align:start position:0% +angels interceded and prevented that so + + + align:start position:0% +angels interceded and prevented that so +this is also a and here's the rock this + + align:start position:0% +this is also a and here's the rock this + + + align:start position:0% +this is also a and here's the rock this +is just a view of the Rock from + + align:start position:0% +is just a view of the Rock from + + + align:start position:0% +is just a view of the Rock from +above + + align:start position:0% + + + + align:start position:0% + +um so that was kind of the Whirlwind + + align:start position:0% +um so that was kind of the Whirlwind + + + align:start position:0% +um so that was kind of the Whirlwind +tour of + + align:start position:0% +tour of + + + align:start position:0% +tour of +Islam um it's obviously you know the the + + align:start position:0% +Islam um it's obviously you know the the + + + align:start position:0% +Islam um it's obviously you know the the +the struggle here is that there is so + + align:start position:0% +the struggle here is that there is so + + + align:start position:0% +the struggle here is that there is so +much culturally loaded in all of these + + align:start position:0% +much culturally loaded in all of these + + + align:start position:0% +much culturally loaded in all of these +examples and so much of a massive + + align:start position:0% +examples and so much of a massive + + + align:start position:0% +examples and so much of a massive +history associated with them that it's + + align:start position:0% +history associated with them that it's + + + align:start position:0% +history associated with them that it's +been very difficult to kind of reduce + + align:start position:0% +been very difficult to kind of reduce + + + align:start position:0% +been very difficult to kind of reduce +the amount of of material + + align:start position:0% +the amount of of material + + + align:start position:0% +the amount of of material +um but that brings me to uh some + + align:start position:0% +um but that brings me to uh some + + + align:start position:0% +um but that brings me to uh some +Christian examples uh and this is really + + align:start position:0% +Christian examples uh and this is really + + + align:start position:0% +Christian examples uh and this is really +uh some medieval my main focus here in + + align:start position:0% +uh some medieval my main focus here in + + + align:start position:0% +uh some medieval my main focus here in +this presentation is the medieval period + + align:start position:0% +this presentation is the medieval period + + + align:start position:0% +this presentation is the medieval period +um in Christianity and this is just on + + align:start position:0% +um in Christianity and this is just on + + + align:start position:0% +um in Christianity and this is just on +the left a drawing from the 15th century + + align:start position:0% +the left a drawing from the 15th century + + + align:start position:0% +the left a drawing from the 15th century +of a pilgrim on his way and on the right + + align:start position:0% +of a pilgrim on his way and on the right + + + align:start position:0% +of a pilgrim on his way and on the right +it's a drawing by Matthew Paris it's a + + align:start position:0% +it's a drawing by Matthew Paris it's a + + + align:start position:0% +it's a drawing by Matthew Paris it's a +sort of a map of a pilgrimage route that + + align:start position:0% +sort of a map of a pilgrimage route that + + + align:start position:0% +sort of a map of a pilgrimage route that +he performed in 1250 that uh is + + align:start position:0% +he performed in 1250 that uh is + + + align:start position:0% +he performed in 1250 that uh is +interesting because it highlights it he + + align:start position:0% +interesting because it highlights it he + + + align:start position:0% +interesting because it highlights it he +actually articulated he drew all the + + align:start position:0% +actually articulated he drew all the + + + align:start position:0% +actually articulated he drew all the +buildings that were along the way um + + align:start position:0% +buildings that were along the way um + + + align:start position:0% +buildings that were along the way um +that he you know all the different + + align:start position:0% +that he you know all the different + + + align:start position:0% +that he you know all the different +buildings that he visited along the way + + align:start position:0% +buildings that he visited along the way + + + align:start position:0% +buildings that he visited along the way +of his pilgrimage route which I found + + align:start position:0% +of his pilgrimage route which I found + + + align:start position:0% +of his pilgrimage route which I found +was very interesting appropriate um um + + align:start position:0% +was very interesting appropriate um um + + + align:start position:0% +was very interesting appropriate um um +the main Center or the focus of the + + align:start position:0% +the main Center or the focus of the + + + align:start position:0% +the main Center or the focus of the +medieval Christian pilgrimage was to St + + align:start position:0% +medieval Christian pilgrimage was to St + + + align:start position:0% +medieval Christian pilgrimage was to St +James of compostella which is located + + align:start position:0% +James of compostella which is located + + + align:start position:0% +James of compostella which is located +out here um in the Iberian Peninsula and + + align:start position:0% +out here um in the Iberian Peninsula and + + + align:start position:0% +out here um in the Iberian Peninsula and +you can see here on this map Paris VI Le + + align:start position:0% +you can see here on this map Paris VI Le + + + align:start position:0% +you can see here on this map Paris VI Le +and AR they all those are the kind of + + align:start position:0% +and AR they all those are the kind of + + + align:start position:0% +and AR they all those are the kind of +main centers of where the pilgrimage + + align:start position:0% +main centers of where the pilgrimage + + + align:start position:0% +main centers of where the pilgrimage +would start and people would progress + + align:start position:0% +would start and people would progress + + + align:start position:0% +would start and people would progress +down these these lines these uh these + + align:start position:0% +down these these lines these uh these + + + align:start position:0% +down these these lines these uh these +essentially these Pilgrim Roots uh + + align:start position:0% +essentially these Pilgrim Roots uh + + + align:start position:0% +essentially these Pilgrim Roots uh +pilgrimage Roots along and hitting + + align:start position:0% +pilgrimage Roots along and hitting + + + align:start position:0% +pilgrimage Roots along and hitting +different holy places along as they go + + align:start position:0% +different holy places along as they go + + + align:start position:0% +different holy places along as they go +uh this is a reconstruction of Santiago + + align:start position:0% +uh this is a reconstruction of Santiago + + + align:start position:0% +uh this is a reconstruction of Santiago +to compostella and um as it would have + + align:start position:0% +to compostella and um as it would have + + + align:start position:0% +to compostella and um as it would have +looked in the 11 around 1100 it's pretty + + align:start position:0% +looked in the 11 around 1100 it's pretty + + + align:start position:0% +looked in the 11 around 1100 it's pretty +interesting it was constructed it was + + align:start position:0% +interesting it was constructed it was + + + align:start position:0% +interesting it was constructed it was +developed by some students and faculty + + align:start position:0% +developed by some students and faculty + + + align:start position:0% +developed by some students and faculty +at UCLA the architecture Department um + + align:start position:0% +at UCLA the architecture Department um + + + align:start position:0% +at UCLA the architecture Department um +I'm not sure how authentic it would be + + align:start position:0% +I'm not sure how authentic it would be + + + align:start position:0% +I'm not sure how authentic it would be +but it's a lot better than the Baroque + + align:start position:0% +but it's a lot better than the Baroque + + + align:start position:0% +but it's a lot better than the Baroque +uh afterthought which is what we have + + align:start position:0% +uh afterthought which is what we have + + + align:start position:0% +uh afterthought which is what we have +right now you can't see the it's um + + align:start position:0% +right now you can't see the it's um + + + align:start position:0% +right now you can't see the it's um +they've the Romanesque structures + + align:start position:0% +they've the Romanesque structures + + + align:start position:0% +they've the Romanesque structures +completely covered with a pretty much a + + align:start position:0% +completely covered with a pretty much a + + + align:start position:0% +completely covered with a pretty much a +broke um structure so this is again we + + align:start position:0% +broke um structure so this is again we + + + align:start position:0% +broke um structure so this is again we +come back to our sacred and profane + + align:start position:0% +come back to our sacred and profane + + + align:start position:0% +come back to our sacred and profane +diagram um + + align:start position:0% +diagram um + + + align:start position:0% +diagram um +and this is sort of how I Envision um + + align:start position:0% +and this is sort of how I Envision um + + + align:start position:0% +and this is sort of how I Envision um +the movement from a Sacred Space uh + + align:start position:0% +the movement from a Sacred Space uh + + + align:start position:0% +the movement from a Sacred Space uh +through the profane to essentially + + align:start position:0% +through the profane to essentially + + + align:start position:0% +through the profane to essentially +there's this very um linear movement to + + align:start position:0% +there's this very um linear movement to + + + align:start position:0% +there's this very um linear movement to +an ultimate sacred place that's you know + + align:start position:0% +an ultimate sacred place that's you know + + + align:start position:0% +an ultimate sacred place that's you know +there's there's some hierarchy here + + align:start position:0% +there's there's some hierarchy here + + + align:start position:0% +there's there's some hierarchy here +there's uh one is process processing + + align:start position:0% +there's uh one is process processing + + + align:start position:0% +there's uh one is process processing +essentially metaphorically through this + + align:start position:0% +essentially metaphorically through this + + + align:start position:0% +essentially metaphorically through this +landscape of the profane and reaches + + align:start position:0% +landscape of the profane and reaches + + + align:start position:0% +landscape of the profane and reaches +these different uh sacred spaces to + + align:start position:0% +these different uh sacred spaces to + + + align:start position:0% +these different uh sacred spaces to +which um they can um you know benefit by + + align:start position:0% +which um they can um you know benefit by + + + align:start position:0% +which um they can um you know benefit by +grace of some sort um and I just we + + align:start position:0% +grace of some sort um and I just we + + + align:start position:0% +grace of some sort um and I just we +can't talk about this without discussing + + align:start position:0% +can't talk about this without discussing + + + align:start position:0% +can't talk about this without discussing +this just massive proliferation of + + align:start position:0% +this just massive proliferation of + + + align:start position:0% +this just massive proliferation of +architecture that just was generated + + align:start position:0% +architecture that just was generated + + + align:start position:0% +architecture that just was generated +around this time and so um this is just + + align:start position:0% +around this time and so um this is just + + + align:start position:0% +around this time and so um this is just +four examples out of the book um + + align:start position:0% +four examples out of the book um + + + align:start position:0% +four examples out of the book um +that show us uh the four examples of + + align:start position:0% +that show us uh the four examples of + + + align:start position:0% +that show us uh the four examples of +pilgrimage churches and you can see + + align:start position:0% +pilgrimage churches and you can see + + + align:start position:0% +pilgrimage churches and you can see +right away the cruciform similarity that + + align:start position:0% +right away the cruciform similarity that + + + align:start position:0% +right away the cruciform similarity that +they share uh the larger abses these AB + + align:start position:0% +they share uh the larger abses these AB + + + align:start position:0% +they share uh the larger abses these AB +cidial which um where relics would be + + align:start position:0% +cidial which um where relics would be + + + align:start position:0% +cidial which um where relics would be +relics would either be located within + + align:start position:0% +relics would either be located within + + + align:start position:0% +relics would either be located within +the apps here or Within These AB cidial + + align:start position:0% +the apps here or Within These AB cidial + + + align:start position:0% +the apps here or Within These AB cidial +uh and so pilgrims would be able to come + + align:start position:0% +uh and so pilgrims would be able to come + + + align:start position:0% +uh and so pilgrims would be able to come +in and and sometimes they would + + align:start position:0% +in and and sometimes they would + + + align:start position:0% +in and and sometimes they would +circumambulate here or they would + + align:start position:0% +circumambulate here or they would + + + align:start position:0% +circumambulate here or they would +process in and out um and very um + + align:start position:0% +process in and out um and very um + + + align:start position:0% +process in and out um and very um +specifically here we have an example + + align:start position:0% +specifically here we have an example + + + align:start position:0% +specifically here we have an example +from sanua in Con in France around + + align:start position:0% +from sanua in Con in France around + + + align:start position:0% +from sanua in Con in France around +11:20 and this is interesting because um + + align:start position:0% +11:20 and this is interesting because um + + + align:start position:0% +11:20 and this is interesting because um +this the the beginning of the story is + + align:start position:0% +this the the beginning of the story is + + + align:start position:0% +this the the beginning of the story is +the um there was a monk who translated + + align:start position:0% +the um there was a monk who translated + + + align:start position:0% +the um there was a monk who translated +or stole um some relics from one place + + align:start position:0% +or stole um some relics from one place + + + align:start position:0% +or stole um some relics from one place +uh uh + + align:start position:0% +uh uh + + + align:start position:0% +uh uh +in um another location in France brought + + align:start position:0% +in um another location in France brought + + + align:start position:0% +in um another location in France brought +them here essentially everybody followed + + align:start position:0% +them here essentially everybody followed + + + align:start position:0% +them here essentially everybody followed +uh and they created this uh large Church + + align:start position:0% +uh and they created this uh large Church + + + align:start position:0% +uh and they created this uh large Church +to kind kind of celebrate the relics of + + align:start position:0% +to kind kind of celebrate the relics of + + + align:start position:0% +to kind kind of celebrate the relics of +s St Faith who was a martyr from the 3rd + + align:start position:0% +s St Faith who was a martyr from the 3rd + + + align:start position:0% +s St Faith who was a martyr from the 3rd +century and here's here's here's her + + align:start position:0% +century and here's here's here's her + + + align:start position:0% +century and here's here's here's her +rendered image and I just wanted to + + align:start position:0% +rendered image and I just wanted to + + + align:start position:0% +rendered image and I just wanted to +quickly read this uh by a clergyman + + align:start position:0% +quickly read this uh by a clergyman + + + align:start position:0% +quickly read this uh by a clergyman +named Berard Doner uh from 1010 he says + + align:start position:0% +named Berard Doner uh from 1010 he says + + + align:start position:0% +named Berard Doner uh from 1010 he says +he's talking about this Relic he says + + align:start position:0% +he's talking about this Relic he says + + + align:start position:0% +he's talking about this Relic he says +when they saw it for the first time all + + align:start position:0% +when they saw it for the first time all + + + align:start position:0% +when they saw it for the first time all +in gold and sparkling with process + + align:start position:0% +in gold and sparkling with process + + + align:start position:0% +in gold and sparkling with process +precious stones and looking like a human + + align:start position:0% +precious stones and looking like a human + + + align:start position:0% +precious stones and looking like a human +face the majority of the peasants + + align:start position:0% +face the majority of the peasants + + + align:start position:0% +face the majority of the peasants +thought that the statue was really + + align:start position:0% +thought that the statue was really + + + align:start position:0% +thought that the statue was really +looking at them and answering their + + align:start position:0% +looking at them and answering their + + + align:start position:0% +looking at them and answering their +prayers with her + + align:start position:0% +prayers with her + + + align:start position:0% +prayers with her +eyes so there's a great deal of Interest + + align:start position:0% +eyes so there's a great deal of Interest + + + align:start position:0% +eyes so there's a great deal of Interest +around these relics the reliquaries and + + align:start position:0% +around these relics the reliquaries and + + + align:start position:0% +around these relics the reliquaries and +the kind of sacredness of these + + align:start position:0% + + + + align:start position:0% + +spaces this is San and more + + align:start position:0% +spaces this is San and more + + + align:start position:0% +spaces this is San and more +views + + align:start position:0% +views + + + align:start position:0% +views +um we can't forget that one of the um + + align:start position:0% +um we can't forget that one of the um + + + align:start position:0% +um we can't forget that one of the um +most important pilgrimages in the + + align:start position:0% +most important pilgrimages in the + + + align:start position:0% +most important pilgrimages in the +medieval period was one that is + + align:start position:0% +medieval period was one that is + + + align:start position:0% +medieval period was one that is +obviously um as mixed + + align:start position:0% +obviously um as mixed + + + align:start position:0% +obviously um as mixed +um not so mixed uh it's pretty um rather + + align:start position:0% +um not so mixed uh it's pretty um rather + + + align:start position:0% +um not so mixed uh it's pretty um rather +controversial uh pilgrimage but that is + + align:start position:0% +controversial uh pilgrimage but that is + + + align:start position:0% +controversial uh pilgrimage but that is +the that everyone's familiar with the + + align:start position:0% +the that everyone's familiar with the + + + align:start position:0% +the that everyone's familiar with the +Crusades um which essentially occur + + align:start position:0% +Crusades um which essentially occur + + + align:start position:0% +Crusades um which essentially occur +between around here the dates that I've + + align:start position:0% +between around here the dates that I've + + + align:start position:0% +between around here the dates that I've +sort of shown and the thing I wanted to + + align:start position:0% +sort of shown and the thing I wanted to + + + align:start position:0% +sort of shown and the thing I wanted to +kind of elicit out of the Crusades was + + align:start position:0% +kind of elicit out of the Crusades was + + + align:start position:0% +kind of elicit out of the Crusades was +this notion of exchange uh of + + align:start position:0% +this notion of exchange uh of + + + align:start position:0% +this notion of exchange uh of +architectural uh architectural + + align:start position:0% +architectural uh architectural + + + align:start position:0% +architectural uh architectural +techniques right so one thing I just + + align:start position:0% +techniques right so one thing I just + + + align:start position:0% +techniques right so one thing I just +want to quickly quickly discuss here is + + align:start position:0% +want to quickly quickly discuss here is + + + align:start position:0% +want to quickly quickly discuss here is +this notion obviously the the Crusades + + align:start position:0% +this notion obviously the the Crusades + + + align:start position:0% +this notion obviously the the Crusades +went to the holy lands what they believe + + align:start position:0% +went to the holy lands what they believe + + + align:start position:0% +went to the holy lands what they believe +were the holy lands which were obviously + + align:start position:0% +were the holy lands which were obviously + + + align:start position:0% +were the holy lands which were obviously +Jerusalem and Bethlehem and all these + + align:start position:0% +Jerusalem and Bethlehem and all these + + + align:start position:0% +Jerusalem and Bethlehem and all these +places along associated with the Life of + + align:start position:0% +places along associated with the Life of + + + align:start position:0% +places along associated with the Life of +Christ um and + + align:start position:0% +Christ um and + + + align:start position:0% +Christ um and +so um what I'm showing here depicting is + + align:start position:0% +so um what I'm showing here depicting is + + + align:start position:0% +so um what I'm showing here depicting is +the AL AXA mosque in Jerusalem which uh + + align:start position:0% +the AL AXA mosque in Jerusalem which uh + + + align:start position:0% +the AL AXA mosque in Jerusalem which uh +is using the uh pointed Arch right so + + align:start position:0% +is using the uh pointed Arch right so + + + align:start position:0% +is using the uh pointed Arch right so +very basically um the Crusaders bring + + align:start position:0% +very basically um the Crusaders bring + + + align:start position:0% +very basically um the Crusaders bring +back some of this + + align:start position:0% +back some of this + + + align:start position:0% +back some of this +technology um that uh pre-existed in + + align:start position:0% +technology um that uh pre-existed in + + + align:start position:0% +technology um that uh pre-existed in +Islam for many years before the + + align:start position:0% +Islam for many years before the + + + align:start position:0% +Islam for many years before the +Crusaders bring it back and there's a we + + align:start position:0% +Crusaders bring it back and there's a we + + + align:start position:0% +Crusaders bring it back and there's a we +see a quick steady development of + + align:start position:0% +see a quick steady development of + + + align:start position:0% +see a quick steady development of +different types of arch systems from the + + align:start position:0% +different types of arch systems from the + + + align:start position:0% +different types of arch systems from the +barrel the Roman kind of groin vaults uh + + align:start position:0% +barrel the Roman kind of groin vaults uh + + + align:start position:0% +barrel the Roman kind of groin vaults uh +and of course the importance here is + + align:start position:0% +and of course the importance here is + + + align:start position:0% +and of course the importance here is +there's this relationship between how + + align:start position:0% +there's this relationship between how + + + align:start position:0% +there's this relationship between how +high you go and how wide you are right + + align:start position:0% +high you go and how wide you are right + + + align:start position:0% +high you go and how wide you are right +that's a fixed point of relationship but + + align:start position:0% +that's a fixed point of relationship but + + + align:start position:0% +that's a fixed point of relationship but +once you introduce the pointed Arch that + + align:start position:0% +once you introduce the pointed Arch that + + + align:start position:0% +once you introduce the pointed Arch that +anything's fair right so that brings me + + align:start position:0% +anything's fair right so that brings me + + + align:start position:0% +anything's fair right so that brings me +to the example of + + align:start position:0% +to the example of + + + align:start position:0% +to the example of +s um which is another pilgrimage church + + align:start position:0% +s um which is another pilgrimage church + + + align:start position:0% +s um which is another pilgrimage church +this is an image this is a stained glass + + align:start position:0% +this is an image this is a stained glass + + + align:start position:0% +this is an image this is a stained glass +image of s and so uh this is the plan + + align:start position:0% +image of s and so uh this is the plan + + + align:start position:0% +image of s and so uh this is the plan +and so we can see here in this apps uh + + align:start position:0% +and so we can see here in this apps uh + + + align:start position:0% +and so we can see here in this apps uh +the + + align:start position:0% +the + + + align:start position:0% +the +ex big additions that um uh that uh + + align:start position:0% +ex big additions that um uh that uh + + + align:start position:0% +ex big additions that um uh that uh +abbid Su uh went through and I wanted to + + align:start position:0% +abbid Su uh went through and I wanted to + + + align:start position:0% +abbid Su uh went through and I wanted to +just quickly read this um videos removed + + align:start position:0% +just quickly read this um videos removed + + + align:start position:0% +just quickly read this um videos removed +due to copyright + + align:start position:0% +due to copyright + + + align:start position:0% +due to copyright +restrictions so he goes on to explain + + align:start position:0% +restrictions so he goes on to explain + + + align:start position:0% +restrictions so he goes on to explain +how horrendous the conditions were in + + align:start position:0% +how horrendous the conditions were in + + + align:start position:0% +how horrendous the conditions were in +viewing these relics so he totally + + align:start position:0% +viewing these relics so he totally + + + align:start position:0% +viewing these relics so he totally +expands the church and you get this + + align:start position:0% +expands the church and you get this + + + align:start position:0% +expands the church and you get this +amazing network of of vaulting going on + + align:start position:0% +amazing network of of vaulting going on + + + align:start position:0% +amazing network of of vaulting going on +here that's brought about essentially by + + align:start position:0% +here that's brought about essentially by + + + align:start position:0% +here that's brought about essentially by +this newer technology of the pointed + + align:start position:0% +this newer technology of the pointed + + + align:start position:0% +this newer technology of the pointed +Arch and I just really wanted to quickly + + align:start position:0% +Arch and I just really wanted to quickly + + + align:start position:0% +Arch and I just really wanted to quickly +briefly go through uh some more recent + + align:start position:0% +briefly go through uh some more recent + + + align:start position:0% +briefly go through uh some more recent +or contemporary things the Santiago to + + align:start position:0% +or contemporary things the Santiago to + + + align:start position:0% +or contemporary things the Santiago to +compostella is still a pilgrimage route + + align:start position:0% +compostella is still a pilgrimage route + + + align:start position:0% +compostella is still a pilgrimage route +that is still practice today these are + + align:start position:0% +that is still practice today these are + + + align:start position:0% +that is still practice today these are +all very contemporary people performing + + align:start position:0% +all very contemporary people performing + + + align:start position:0% +all very contemporary people performing +this this is a sign in France that + + align:start position:0% +this this is a sign in France that + + + align:start position:0% +this this is a sign in France that +indicates it's 953 kilometers um because + + align:start position:0% +indicates it's 953 kilometers um because + + + align:start position:0% +indicates it's 953 kilometers um because +people are still taking these + + align:start position:0% +people are still taking these + + + align:start position:0% +people are still taking these +pilgrimmage frots um and then in Lords + + align:start position:0% +pilgrimmage frots um and then in Lords + + + align:start position:0% +pilgrimmage frots um and then in Lords +in France I wanted to just highlight the + + align:start position:0% +in France I wanted to just highlight the + + + align:start position:0% +in France I wanted to just highlight the +story of bernardet subus who in 1858 saw + + align:start position:0% +story of bernardet subus who in 1858 saw + + + align:start position:0% +story of bernardet subus who in 1858 saw +a sighting of the Virgin Mary + + align:start position:0% +a sighting of the Virgin Mary + + + align:start position:0% +a sighting of the Virgin Mary +um in this nowhere Village uh that + + align:start position:0% +um in this nowhere Village uh that + + + align:start position:0% +um in this nowhere Village uh that +didn't even have a railroad station or + + align:start position:0% +didn't even have a railroad station or + + + align:start position:0% +didn't even have a railroad station or +anything it was extremely difficult to + + align:start position:0% +anything it was extremely difficult to + + + align:start position:0% +anything it was extremely difficult to +get there and she was an uneducated um + + align:start position:0% +get there and she was an uneducated um + + + align:start position:0% +get there and she was an uneducated um +illiterate peasant girl essentially so + + align:start position:0% +illiterate peasant girl essentially so + + + align:start position:0% +illiterate peasant girl essentially so +to speak who saw this vision and turned + + align:start position:0% +to speak who saw this vision and turned + + + align:start position:0% +to speak who saw this vision and turned +this place essentially her vision turned + + align:start position:0% +this place essentially her vision turned + + + align:start position:0% +this place essentially her vision turned +it into this um this key Central + + align:start position:0% +it into this um this key Central + + + align:start position:0% +it into this um this key Central +Christian uh pilgrimage location and + + align:start position:0% +Christian uh pilgrimage location and + + + align:start position:0% +Christian uh pilgrimage location and +here you can see on the bottom right a + + align:start position:0% +here you can see on the bottom right a + + + align:start position:0% +here you can see on the bottom right a +very contemporary view of pilgrims um + + align:start position:0% +very contemporary view of pilgrims um + + + align:start position:0% +very contemporary view of pilgrims um +coming here again and then bernardet + + align:start position:0% +coming here again and then bernardet + + + align:start position:0% +coming here again and then bernardet +dies and they turn her into a Rec Relic + + align:start position:0% +dies and they turn her into a Rec Relic + + + align:start position:0% +dies and they turn her into a Rec Relic +essentially uh so it's sort of it's very + + align:start position:0% +essentially uh so it's sort of it's very + + + align:start position:0% +essentially uh so it's sort of it's very +interesting this whole process that's + + align:start position:0% +interesting this whole process that's + + + align:start position:0% +interesting this whole process that's +occurring um and again in later + + align:start position:0% +occurring um and again in later + + + align:start position:0% +occurring um and again in later +Christianity we have we it's it's + + align:start position:0% +Christianity we have we it's it's + + + align:start position:0% +Christianity we have we it's it's +interesting because we almost come back + + align:start position:0% +interesting because we almost come back + + + align:start position:0% +interesting because we almost come back +in a full circle back to Carnac where + + align:start position:0% +in a full circle back to Carnac where + + + align:start position:0% +in a full circle back to Carnac where +where where we are there's an + + align:start position:0% +where where we are there's an + + + align:start position:0% +where where we are there's an +understanding of the the movement or the + + align:start position:0% +understanding of the the movement or the + + + align:start position:0% +understanding of the the movement or the +procession of the Sacred the sacred + + align:start position:0% +procession of the Sacred the sacred + + + align:start position:0% +procession of the Sacred the sacred +actually is moved from one location to + + align:start position:0% +actually is moved from one location to + + + align:start position:0% +actually is moved from one location to +another and on the left we have an + + align:start position:0% +another and on the left we have an + + + align:start position:0% +another and on the left we have an +example of in Poland on the upper right + + align:start position:0% +example of in Poland on the upper right + + + align:start position:0% +example of in Poland on the upper right +in Italy and then on the bottom right we + + align:start position:0% +in Italy and then on the bottom right we + + + align:start position:0% +in Italy and then on the bottom right we +have the famous s Santa in Spain um the + + align:start position:0% +have the famous s Santa in Spain um the + + + align:start position:0% +have the famous s Santa in Spain um the +holy weeks ceremony where um you have + + align:start position:0% +holy weeks ceremony where um you have + + + align:start position:0% +holy weeks ceremony where um you have +quite an amazing amount proliferation of + + align:start position:0% +quite an amazing amount proliferation of + + + align:start position:0% +quite an amazing amount proliferation of +processions um and more recently we also + + align:start position:0% +processions um and more recently we also + + + align:start position:0% +processions um and more recently we also +have + + align:start position:0% +have + + + align:start position:0% +have +um uh more Christian processions with uh + + align:start position:0% +um uh more Christian processions with uh + + + align:start position:0% +um uh more Christian processions with uh +pilgrimages to see all kinds of things + + align:start position:0% +pilgrimages to see all kinds of things + + + align:start position:0% +pilgrimages to see all kinds of things +right Rome this whole Space is all about + + align:start position:0% +right Rome this whole Space is all about + + + align:start position:0% +right Rome this whole Space is all about +procession and pilgrimage um and if you + + align:start position:0% +procession and pilgrimage um and if you + + + align:start position:0% +procession and pilgrimage um and if you +ever want to go to any of these places + + align:start position:0% +ever want to go to any of these places + + + align:start position:0% +ever want to go to any of these places +you can hop on online and um click if + + align:start position:0% +you can hop on online and um click if + + + align:start position:0% +you can hop on online and um click if +you're Protestant my interest is + + align:start position:0% +you're Protestant my interest is + + + align:start position:0% +you're Protestant my interest is +Protestant or whatever and then um if + + align:start position:0% +Protestant or whatever and then um if + + + align:start position:0% +Protestant or whatever and then um if +you're Buddhist you can find Buddhist + + align:start position:0% +you're Buddhist you can find Buddhist + + + align:start position:0% +you're Buddhist you can find Buddhist +pilgrimages to go to lumini bodaya + + align:start position:0% +pilgrimages to go to lumini bodaya + + + align:start position:0% +pilgrimages to go to lumini bodaya +wherever um the Hajj of course is you + + align:start position:0% +wherever um the Hajj of course is you + + + align:start position:0% +wherever um the Hajj of course is you +know not a problem at all they can do + + align:start position:0% +know not a problem at all they can do + + + align:start position:0% +know not a problem at all they can do +that for you there's packages trips from + + align:start position:0% +that for you there's packages trips from + + + align:start position:0% +that for you there's packages trips from +JFK you can even rent a pilgrim which is + + align:start position:0% +JFK you can even rent a pilgrim which is + + + align:start position:0% +JFK you can even rent a pilgrim which is +a medieval notion the + + align:start position:0% +a medieval notion the + + + align:start position:0% +a medieval notion the +perrino picun CAA which is where you + + align:start position:0% +perrino picun CAA which is where you + + + align:start position:0% +perrino picun CAA which is where you +would pay a pilgrim to go in in your + + align:start position:0% +would pay a pilgrim to go in in your + + + align:start position:0% +would pay a pilgrim to go in in your +stead um and this notion you can do it's + + align:start position:0% +stead um and this notion you can do it's + + + align:start position:0% +stead um and this notion you can do it's +interesting I only I only raised this + + align:start position:0% +interesting I only I only raised this + + + align:start position:0% +interesting I only I only raised this +issue because it's interesting because + + align:start position:0% +issue because it's interesting because + + + align:start position:0% +issue because it's interesting because +it's connected to architecture in a very + + align:start position:0% +it's connected to architecture in a very + + + align:start position:0% +it's connected to architecture in a very +interesting way so if you do go onto + + align:start position:0% +interesting way so if you do go onto + + + align:start position:0% +interesting way so if you do go onto +this website and rent a pilgrim this guy + + align:start position:0% +this website and rent a pilgrim this guy + + + align:start position:0% +this website and rent a pilgrim this guy +will walk for you and you'll pay him and + + align:start position:0% +will walk for you and you'll pay him and + + + align:start position:0% +will walk for you and you'll pay him and +he'll do the walk and the money will go + + align:start position:0% +he'll do the walk and the money will go + + + align:start position:0% +he'll do the walk and the money will go +to fund the renovation of the City + + align:start position:0% +to fund the renovation of the City + + + align:start position:0% +to fund the renovation of the City +Church uh St Jacob in Rottenberg in + + align:start position:0% +Church uh St Jacob in Rottenberg in + + + align:start position:0% +Church uh St Jacob in Rottenberg in +Germany and so it's very interesting and + + align:start position:0% +Germany and so it's very interesting and + + + align:start position:0% +Germany and so it's very interesting and +then of course you get a emblem that you + + align:start position:0% +then of course you get a emblem that you + + + align:start position:0% +then of course you get a emblem that you +went on the pilgrimage right your your + + align:start position:0% +went on the pilgrimage right your your + + + align:start position:0% +went on the pilgrimage right your your +scallop pendant + + align:start position:0% +scallop pendant + + + align:start position:0% +scallop pendant +um and there are all kinds of + + align:start position:0% +um and there are all kinds of + + + align:start position:0% +um and there are all kinds of +contemporary guides to St James uh these + + align:start position:0% +contemporary guides to St James uh these + + + align:start position:0% +contemporary guides to St James uh these +are this is an image of the Buddhists + + align:start position:0% +are this is an image of the Buddhists + + + align:start position:0% +are this is an image of the Buddhists +doing the Santiago de compostella so + + align:start position:0% +doing the Santiago de compostella so + + + align:start position:0% +doing the Santiago de compostella so +there's this kind of very interesting + + align:start position:0% +there's this kind of very interesting + + + align:start position:0% +there's this kind of very interesting +Global thing going on here um you know + + align:start position:0% +Global thing going on here um you know + + + align:start position:0% +Global thing going on here um you know +just this notion of a Sacred Space uh + + align:start position:0% +just this notion of a Sacred Space uh + + + align:start position:0% +just this notion of a Sacred Space uh +following the path of a sacred no matter + + align:start position:0% +following the path of a sacred no matter + + + align:start position:0% +following the path of a sacred no matter +what kind of denomination or whatever it + + align:start position:0% +what kind of denomination or whatever it + + + align:start position:0% +what kind of denomination or whatever it +is um again uh secular pilgrimages not + + align:start position:0% +is um again uh secular pilgrimages not + + + align:start position:0% +is um again uh secular pilgrimages not +the focus necessarily of the talk but + + align:start position:0% +the focus necessarily of the talk but + + + align:start position:0% +the focus necessarily of the talk but +still an important um aspect to popular + + align:start position:0% +still an important um aspect to popular + + + align:start position:0% +still an important um aspect to popular +culture uh that we're surrounded with + + align:start position:0% +culture uh that we're surrounded with + + + align:start position:0% +culture uh that we're surrounded with +today JFK and Vietnam + + align:start position:0% +today JFK and Vietnam + + + align:start position:0% +today JFK and Vietnam +memorial um and of course Elvis we can't + + align:start position:0% +memorial um and of course Elvis we can't + + + align:start position:0% +memorial um and of course Elvis we can't +leave uh hit Grace land out with his + + align:start position:0% +leave uh hit Grace land out with his + + + align:start position:0% +leave uh hit Grace land out with his +tomb here and um there's just if the + + align:start position:0% +tomb here and um there's just if the + + + align:start position:0% +tomb here and um there's just if the +closer you look there's just these very + + align:start position:0% +closer you look there's just these very + + + align:start position:0% +closer you look there's just these very +odd stories about people this is a this + + align:start position:0% +odd stories about people this is a this + + + align:start position:0% +odd stories about people this is a this +is a former military installation in the + + align:start position:0% +is a former military installation in the + + + align:start position:0% +is a former military installation in the +desert that people flock to every year + + align:start position:0% +desert that people flock to every year + + + align:start position:0% +desert that people flock to every year +and do these um interesting + + align:start position:0% +and do these um interesting + + + align:start position:0% +and do these um interesting +sculptures but basically um I think it's + + align:start position:0% +sculptures but basically um I think it's + + + align:start position:0% +sculptures but basically um I think it's +it's important to think about the + + align:start position:0% +it's important to think about the + + + align:start position:0% +it's important to think about the +Contemporary um contemporary pilgrimage + + align:start position:0% +Contemporary um contemporary pilgrimage + + + align:start position:0% +Contemporary um contemporary pilgrimage +and how it relates to our historical + + align:start position:0% +and how it relates to our historical + + + align:start position:0% +and how it relates to our historical +examples that we just discussed and how + + align:start position:0% +examples that we just discussed and how + + + align:start position:0% +examples that we just discussed and how +it's continually readapted and + + align:start position:0% +it's continually readapted and + + + align:start position:0% +it's continually readapted and +interpreted through different world + + align:start position:0% +interpreted through different world + + + align:start position:0% +interpreted through different world +cultures and traditions and um \ No newline at end of file diff --git a/SC8K6gNAIL4.txt b/SC8K6gNAIL4.txt new file mode 100644 index 0000000000000000000000000000000000000000..f2c2ae21dbbd6d449c2d8e406ad0514924847b9a --- /dev/null +++ b/SC8K6gNAIL4.txt @@ -0,0 +1,19613 @@ +align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so let me sort of just recap what we + + align:start position:0% +so let me sort of just recap what we + + + align:start position:0% +so let me sort of just recap what we +discussed last time + + align:start position:0% +discussed last time + + + align:start position:0% +discussed last time +fairly quickly and then we want to move + + align:start position:0% +fairly quickly and then we want to move + + + align:start position:0% +fairly quickly and then we want to move +to empirical evidence on a variety of + + align:start position:0% +to empirical evidence on a variety of + + + align:start position:0% +to empirical evidence on a variety of +settings + + align:start position:0% +settings + + + align:start position:0% +settings +we might not get through all of the + + align:start position:0% +we might not get through all of the + + + align:start position:0% +we might not get through all of the +slides that's fine + + align:start position:0% +slides that's fine + + + align:start position:0% +slides that's fine +in that case we'll just discuss some of + + align:start position:0% +in that case we'll just discuss some of + + + align:start position:0% +in that case we'll just discuss some of +this in recitation + + align:start position:0% +this in recitation + + + align:start position:0% +this in recitation +so let me sort of recap what + + align:start position:0% +so let me sort of recap what + + + align:start position:0% +so let me sort of recap what +in their 1979 article um were + + align:start position:0% +in their 1979 article um were + + + align:start position:0% +in their 1979 article um were +proposing based on a bunch of + + align:start position:0% +proposing based on a bunch of + + + align:start position:0% +proposing based on a bunch of +experiments and empirical evidence that + + align:start position:0% +experiments and empirical evidence that + + + align:start position:0% +experiments and empirical evidence that +they had collected + + align:start position:0% +they had collected + + + align:start position:0% +they had collected +so their theory + + align:start position:0% +so their theory + + + align:start position:0% +so their theory +is called prospect theory what they + + align:start position:0% +is called prospect theory what they + + + align:start position:0% +is called prospect theory what they +proposed versions of prospect theory is + + align:start position:0% +proposed versions of prospect theory is + + + align:start position:0% +proposed versions of prospect theory is +essentially versions of reference + + align:start position:0% +essentially versions of reference + + + align:start position:0% +essentially versions of reference +dependent utility + + align:start position:0% +dependent utility + + + align:start position:0% +dependent utility +have been used are used prominently now + + align:start position:0% +have been used are used prominently now + + + align:start position:0% +have been used are used prominently now +in economics + + align:start position:0% +in economics + + + align:start position:0% +in economics +so the first thing that they proposed + + align:start position:0% +so the first thing that they proposed + + + align:start position:0% +so the first thing that they proposed +was what matters what the carrier of + + align:start position:0% +was what matters what the carrier of + + + align:start position:0% +was what matters what the carrier of +utility is is + + align:start position:0% +utility is is + + + align:start position:0% +utility is is +changes rather than levels that's to say + + align:start position:0% +changes rather than levels that's to say + + + align:start position:0% +changes rather than levels that's to say +it doesn't matter for you necessarily + + align:start position:0% +it doesn't matter for you necessarily + + + align:start position:0% +it doesn't matter for you necessarily +how warm it is it matters kind of what's + + align:start position:0% +how warm it is it matters kind of what's + + + align:start position:0% +how warm it is it matters kind of what's +the change of temperature compared to + + align:start position:0% +the change of temperature compared to + + + align:start position:0% +the change of temperature compared to +yesterday + + align:start position:0% +yesterday + + + align:start position:0% +yesterday +it doesn't matter that much how much + + align:start position:0% +it doesn't matter that much how much + + + align:start position:0% +it doesn't matter that much how much +money people have in total it matters + + align:start position:0% +money people have in total it matters + + + align:start position:0% +money people have in total it matters +how much the changes + + align:start position:0% +how much the changes + + + align:start position:0% +how much the changes +relative to what they had previously + + align:start position:0% +relative to what they had previously + + + align:start position:0% +relative to what they had previously +more generally what matters for people + + align:start position:0% +more generally what matters for people + + + align:start position:0% +more generally what matters for people +is essentially a certain + + align:start position:0% +is essentially a certain + + + align:start position:0% +is essentially a certain +consumption or the like relative to + + align:start position:0% +consumption or the like relative to + + + align:start position:0% +consumption or the like relative to +reference point as opposed to an + + align:start position:0% +reference point as opposed to an + + + align:start position:0% +reference point as opposed to an +absolute + + align:start position:0% +absolute + + + align:start position:0% +absolute +terms second loss aversion this is + + align:start position:0% +terms second loss aversion this is + + + align:start position:0% +terms second loss aversion this is +losses + + align:start position:0% +losses + + + align:start position:0% +losses +loom larger than gains and we had some + + align:start position:0% +loom larger than gains and we had some + + + align:start position:0% +loom larger than gains and we had some +evidence of that in the last lecture + + align:start position:0% +evidence of that in the last lecture + + + align:start position:0% +evidence of that in the last lecture +that's to say if you lose some money or + + align:start position:0% +that's to say if you lose some money or + + + align:start position:0% +that's to say if you lose some money or +some consumption + + align:start position:0% +some consumption + + + align:start position:0% +some consumption +or anything else grades etc + + align:start position:0% +or anything else grades etc + + + align:start position:0% +or anything else grades etc +a lot relative to either your status quo + + align:start position:0% +a lot relative to either your status quo + + + align:start position:0% +a lot relative to either your status quo +or to your expectation + + align:start position:0% +or to your expectation + + + align:start position:0% +or to your expectation +looms larger is more important hurts + + align:start position:0% +looms larger is more important hurts + + + align:start position:0% +looms larger is more important hurts +more than a gain of the same magnitude + + align:start position:0% +more than a gain of the same magnitude + + + align:start position:0% +more than a gain of the same magnitude +in the positive direction and number + + align:start position:0% +in the positive direction and number + + + align:start position:0% +in the positive direction and number +three which you talked about + + align:start position:0% +three which you talked about + + + align:start position:0% +three which you talked about +quickly is what's referred to as + + align:start position:0% +quickly is what's referred to as + + + align:start position:0% +quickly is what's referred to as +diminishing sensitivity + + align:start position:0% +diminishing sensitivity + + + align:start position:0% +diminishing sensitivity +that is um people are risk averse in the + + align:start position:0% +that is um people are risk averse in the + + + align:start position:0% +that is um people are risk averse in the +gain domain but risk loving in the last + + align:start position:0% +gain domain but risk loving in the last + + + align:start position:0% +gain domain but risk loving in the last +domain + + align:start position:0% +domain + + + align:start position:0% +domain +that's to say um um if you are for + + align:start position:0% +that's to say um um if you are for + + + align:start position:0% +that's to say um um if you are for +example if you think about distance + + align:start position:0% +example if you think about distance + + + align:start position:0% +example if you think about distance +time chance and the like going from zero + + align:start position:0% +time chance and the like going from zero + + + align:start position:0% +time chance and the like going from zero +to one + + align:start position:0% +to one + + + align:start position:0% +to one +or from one to two from two to three is + + align:start position:0% +or from one to two from two to three is + + + align:start position:0% +or from one to two from two to three is +more important for you + + align:start position:0% +more important for you + + + align:start position:0% +more important for you +than going from like 100 to 101 101 102 + + align:start position:0% +than going from like 100 to 101 101 102 + + + align:start position:0% +than going from like 100 to 101 101 102 +and so on essentially + + align:start position:0% +and so on essentially + + + align:start position:0% +and so on essentially +uh the further you'll go away from like + + align:start position:0% +uh the further you'll go away from like + + + align:start position:0% +uh the further you'll go away from like +your + + align:start position:0% +your + + + align:start position:0% +your +status quo your reference point uh any + + align:start position:0% +status quo your reference point uh any + + + align:start position:0% +status quo your reference point uh any +marginal changes like diminishing + + align:start position:0% +marginal changes like diminishing + + + align:start position:0% +marginal changes like diminishing +right and that's true for both the gain + + align:start position:0% +right and that's true for both the gain + + + align:start position:0% +right and that's true for both the gain +domain and um + + align:start position:0% +domain and um + + + align:start position:0% +domain and um +uh the loss domain so these are sort of + + align:start position:0% +uh the loss domain so these are sort of + + + align:start position:0% +uh the loss domain so these are sort of +the main three characteristics + + align:start position:0% +the main three characteristics + + + align:start position:0% +the main three characteristics +related to what kind of first we call + + align:start position:0% +related to what kind of first we call + + + align:start position:0% +related to what kind of first we call +the value function we can think of this + + align:start position:0% +the value function we can think of this + + + align:start position:0% +the value function we can think of this +as essentially a version of the utility + + align:start position:0% +as essentially a version of the utility + + + align:start position:0% +as essentially a version of the utility +function + + align:start position:0% +function + + + align:start position:0% +function +there's a fourth characteristic which is + + align:start position:0% +there's a fourth characteristic which is + + + align:start position:0% +there's a fourth characteristic which is +probability weighting which we're not + + align:start position:0% +probability weighting which we're not + + + align:start position:0% +probability weighting which we're not +going to talk about at least + + align:start position:0% +going to talk about at least + + + align:start position:0% +going to talk about at least +for now are there any questions on these + + align:start position:0% +for now are there any questions on these + + + align:start position:0% +for now are there any questions on these +three + + align:start position:0% +three + + + align:start position:0% +three +things so far + + align:start position:0% + + + + align:start position:0% + +okay so now + + align:start position:0% +okay so now + + + align:start position:0% +okay so now +prospect theory is then what kahneman + + align:start position:0% +prospect theory is then what kahneman + + + align:start position:0% +prospect theory is then what kahneman +and versky were proposing they were + + align:start position:0% +and versky were proposing they were + + + align:start position:0% +and versky were proposing they were +essentially saying like + + align:start position:0% +essentially saying like + + + align:start position:0% +essentially saying like +instead of having concave utility which + + align:start position:0% +instead of having concave utility which + + + align:start position:0% +instead of having concave utility which +i showed you um uh + + align:start position:0% +i showed you um uh + + + align:start position:0% +i showed you um uh +last week instead your utility function + + align:start position:0% +last week instead your utility function + + + align:start position:0% +last week instead your utility function +may look like + + align:start position:0% +may look like + + + align:start position:0% +may look like +this and what are sort of the features + + align:start position:0% +this and what are sort of the features + + + align:start position:0% +this and what are sort of the features +of this utility function what what are + + align:start position:0% +of this utility function what what are + + + align:start position:0% +of this utility function what what are +the + + align:start position:0% +the + + + align:start position:0% +the +three key features that i just showed + + align:start position:0% +three key features that i just showed + + + align:start position:0% +three key features that i just showed +you how they're showing up in this + + align:start position:0% +you how they're showing up in this + + + align:start position:0% +you how they're showing up in this +function here + + align:start position:0% +function here + + + align:start position:0% +function here +yes uh c minus where is the changes + + align:start position:0% +yes uh c minus where is the changes + + + align:start position:0% +yes uh c minus where is the changes +right so the carrier of the utility + + align:start position:0% +right so the carrier of the utility + + + align:start position:0% +right so the carrier of the utility +function so what we have here is like c + + align:start position:0% +function so what we have here is like c + + + align:start position:0% +function so what we have here is like c +and r + + align:start position:0% +and r + + + align:start position:0% +and r +uh c is like consumption that could be + + align:start position:0% +uh c is like consumption that could be + + + align:start position:0% +uh c is like consumption that could be +anything that could be apples that could + + align:start position:0% +anything that could be apples that could + + + align:start position:0% +anything that could be apples that could +be bananas that could be uh + + align:start position:0% +be bananas that could be uh + + + align:start position:0% +be bananas that could be uh +sort of how much money people have + + align:start position:0% +sort of how much money people have + + + align:start position:0% +sort of how much money people have +available to consume overall + + align:start position:0% +available to consume overall + + + align:start position:0% +available to consume overall +the carrier of the utility function is + + align:start position:0% +the carrier of the utility function is + + + align:start position:0% +the carrier of the utility function is +not c itself it's c minus r so it's c + + align:start position:0% +not c itself it's c minus r so it's c + + + align:start position:0% +not c itself it's c minus r so it's c +relative to some reference point r + + align:start position:0% +relative to some reference point r + + + align:start position:0% +relative to some reference point r +that's exactly right + + align:start position:0% +that's exactly right + + + align:start position:0% +that's exactly right +so and if r is the status quo if r is + + align:start position:0% +so and if r is the status quo if r is + + + align:start position:0% +so and if r is the status quo if r is +how much do we have right now or the + + align:start position:0% +how much do we have right now or the + + + align:start position:0% +how much do we have right now or the +person has right now + + align:start position:0% +person has right now + + + align:start position:0% +person has right now +c minus r is a change relative to the + + align:start position:0% +c minus r is a change relative to the + + + align:start position:0% +c minus r is a change relative to the +status quo + + align:start position:0% +status quo + + + align:start position:0% +status quo +notice that r uh we're going to talk + + align:start position:0% +notice that r uh we're going to talk + + + align:start position:0% +notice that r uh we're going to talk +about this a little bit could be also + + align:start position:0% +about this a little bit could be also + + + align:start position:0% +about this a little bit could be also +other things it doesn't have to be + + align:start position:0% +other things it doesn't have to be + + + align:start position:0% +other things it doesn't have to be +necessarily the status quo + + align:start position:0% +necessarily the status quo + + + align:start position:0% +necessarily the status quo +it could be also people's expectation or + + align:start position:0% +it could be also people's expectation or + + + align:start position:0% +it could be also people's expectation or +their goals or their aspirations for the + + align:start position:0% +their goals or their aspirations for the + + + align:start position:0% +their goals or their aspirations for the +future + + align:start position:0% +future + + + align:start position:0% +future +right the key part is however what + + align:start position:0% +right the key part is however what + + + align:start position:0% +right the key part is however what +matters is the first thing i was saying + + align:start position:0% +matters is the first thing i was saying + + + align:start position:0% +matters is the first thing i was saying +like + + align:start position:0% +like + + + align:start position:0% +like +it's changes rather than levels changes + + align:start position:0% +it's changes rather than levels changes + + + align:start position:0% +it's changes rather than levels changes +relative to some + + align:start position:0% +relative to some + + + align:start position:0% +relative to some +reference point or consumption relative + + align:start position:0% +reference point or consumption relative + + + align:start position:0% +reference point or consumption relative +to some reference point that's number + + align:start position:0% +to some reference point that's number + + + align:start position:0% +to some reference point that's number +one yes + + align:start position:0% + + + + align:start position:0% + +yes uh the curve flattens out which is + + align:start position:0% +yes uh the curve flattens out which is + + + align:start position:0% +yes uh the curve flattens out which is +diminishing + + align:start position:0% +diminishing + + + align:start position:0% +diminishing +exactly the curve flattens out in both + + align:start position:0% +exactly the curve flattens out in both + + + align:start position:0% +exactly the curve flattens out in both +directions that's diminishing + + align:start position:0% +directions that's diminishing + + + align:start position:0% +directions that's diminishing +sensitivity + + align:start position:0% +sensitivity + + + align:start position:0% +sensitivity +it's essentially concave in the in the + + align:start position:0% +it's essentially concave in the in the + + + align:start position:0% +it's essentially concave in the in the +gain domain of the domain where like + + align:start position:0% +gain domain of the domain where like + + + align:start position:0% +gain domain of the domain where like +c is larger than r and it's convex in + + align:start position:0% +c is larger than r and it's convex in + + + align:start position:0% +c is larger than r and it's convex in +the last domain where c is + + align:start position:0% +the last domain where c is + + + align:start position:0% +the last domain where c is +smaller than r right + + align:start position:0% +smaller than r right + + + align:start position:0% +smaller than r right +and that's exactly the issue that + + align:start position:0% +and that's exactly the issue that + + + align:start position:0% +and that's exactly the issue that +essentially the first the marginal + + align:start position:0% +essentially the first the marginal + + + align:start position:0% +essentially the first the marginal +change going from like uh say one to two + + align:start position:0% +change going from like uh say one to two + + + align:start position:0% +change going from like uh say one to two +is relatively large compared to a + + align:start position:0% +is relatively large compared to a + + + align:start position:0% +is relatively large compared to a +marginal change going from 10 to 11 + + align:start position:0% +marginal change going from 10 to 11 + + + align:start position:0% +marginal change going from 10 to 11 +that's both going in the right direction + + align:start position:0% +that's both going in the right direction + + + align:start position:0% +that's both going in the right direction +in the gains domain and the left + + align:start position:0% +in the gains domain and the left + + + align:start position:0% +in the gains domain and the left +direction and the last domain + + align:start position:0% +direction and the last domain + + + align:start position:0% +direction and the last domain +uh yes um for the loss of version um the + + align:start position:0% +uh yes um for the loss of version um the + + + align:start position:0% +uh yes um for the loss of version um the +left side is cheaper than the right side + + align:start position:0% +left side is cheaper than the right side + + + align:start position:0% +left side is cheaper than the right side +exactly in particular there's like kink + + align:start position:0% +exactly in particular there's like kink + + + align:start position:0% +exactly in particular there's like kink +in and this function + + align:start position:0% +in and this function + + + align:start position:0% +in and this function +uh when you look at zero where + + align:start position:0% +uh when you look at zero where + + + align:start position:0% +uh when you look at zero where +essentially um + + align:start position:0% +essentially um + + + align:start position:0% +essentially um +the gain and loss domain was c equals r + + align:start position:0% +the gain and loss domain was c equals r + + + align:start position:0% +the gain and loss domain was c equals r +uh the gain and loss domain + + align:start position:0% +uh the gain and loss domain + + + align:start position:0% +uh the gain and loss domain +intersect uh there we have a kink in the + + align:start position:0% +intersect uh there we have a kink in the + + + align:start position:0% +intersect uh there we have a kink in the +in the value function and the utility + + align:start position:0% +in the value function and the utility + + + align:start position:0% +in the value function and the utility +function uh which essentially exactly is + + align:start position:0% +function uh which essentially exactly is + + + align:start position:0% +function uh which essentially exactly is +the last domain + + align:start position:0% +the last domain + + + align:start position:0% +the last domain +at the last aversion which is like going + + align:start position:0% +at the last aversion which is like going + + + align:start position:0% +at the last aversion which is like going +to the right it's less deep than going + + align:start position:0% +to the right it's less deep than going + + + align:start position:0% +to the right it's less deep than going +to the left + + align:start position:0% +to the left + + + align:start position:0% +to the left +but differently if you lose if you're + + align:start position:0% +but differently if you lose if you're + + + align:start position:0% +but differently if you lose if you're +sort of below the reference point + + align:start position:0% +sort of below the reference point + + + align:start position:0% +sort of below the reference point +that's more painful than being the same + + align:start position:0% +that's more painful than being the same + + + align:start position:0% +that's more painful than being the same +amount of uh + + align:start position:0% +amount of uh + + + align:start position:0% +amount of uh +units to be above the reference point + + align:start position:0% +units to be above the reference point + + + align:start position:0% +units to be above the reference point +that's number two that's essentially + + align:start position:0% +that's number two that's essentially + + + align:start position:0% +that's number two that's essentially +exactly the last aversion + + align:start position:0% +exactly the last aversion + + + align:start position:0% +exactly the last aversion +so i just wrote down all of that again + + align:start position:0% +so i just wrote down all of that again + + + align:start position:0% +so i just wrote down all of that again +let me repeat caro the utility has + + align:start position:0% +let me repeat caro the utility has + + + align:start position:0% +let me repeat caro the utility has +changes relative to the reference point + + align:start position:0% +changes relative to the reference point + + + align:start position:0% +changes relative to the reference point +excuse me rather than levels second + + align:start position:0% +excuse me rather than levels second + + + align:start position:0% +excuse me rather than levels second +there's loss of version there's a kink + + align:start position:0% +there's loss of version there's a kink + + + align:start position:0% +there's loss of version there's a kink +at zero in this function and three + + align:start position:0% +at zero in this function and three + + + align:start position:0% +at zero in this function and three +there's diminishing sensitivity which is + + align:start position:0% +there's diminishing sensitivity which is + + + align:start position:0% +there's diminishing sensitivity which is +concavity and gains and convexity in + + align:start position:0% +concavity and gains and convexity in + + + align:start position:0% +concavity and gains and convexity in +losses + + align:start position:0% + + + + align:start position:0% + +any questions on that + + align:start position:0% + + + + align:start position:0% + +now a key question here is i'm going to + + align:start position:0% +now a key question here is i'm going to + + + align:start position:0% +now a key question here is i'm going to +sort of flag this we're going to talk + + align:start position:0% +sort of flag this we're going to talk + + + align:start position:0% +sort of flag this we're going to talk +about this a little bit at the end + + align:start position:0% +about this a little bit at the end + + + align:start position:0% +about this a little bit at the end +of the lecture we're going to talk to + + align:start position:0% +of the lecture we're going to talk to + + + align:start position:0% +of the lecture we're going to talk to +this a little bit in the next problem + + align:start position:0% +this a little bit in the next problem + + + align:start position:0% +this a little bit in the next problem +set + + align:start position:0% +set + + + align:start position:0% +set +is kind of like how is the reference + + align:start position:0% +is kind of like how is the reference + + + align:start position:0% +is kind of like how is the reference +point determined and does it matter + + align:start position:0% +point determined and does it matter + + + align:start position:0% +point determined and does it matter +as i said before in kanaman firski's + + align:start position:0% +as i said before in kanaman firski's + + + align:start position:0% +as i said before in kanaman firski's +work a lot of the reference point is the + + align:start position:0% +work a lot of the reference point is the + + + align:start position:0% +work a lot of the reference point is the +status quo + + align:start position:0% +status quo + + + align:start position:0% +status quo +so they essentially postulated the + + align:start position:0% +so they essentially postulated the + + + align:start position:0% +so they essentially postulated the +status quo is what would really + + align:start position:0% +status quo is what would really + + + align:start position:0% +status quo is what would really +what matters originally i think people + + align:start position:0% +what matters originally i think people + + + align:start position:0% +what matters originally i think people +have moved towards saying like the + + align:start position:0% +have moved towards saying like the + + + align:start position:0% +have moved towards saying like the +reference point and this is what kossig + + align:start position:0% +reference point and this is what kossig + + + align:start position:0% +reference point and this is what kossig +and raven and others have + + align:start position:0% +and raven and others have + + + align:start position:0% +and raven and others have +written down in their models of + + align:start position:0% +written down in their models of + + + align:start position:0% +written down in their models of +reference dependence utility and + + align:start position:0% +reference dependence utility and + + + align:start position:0% +reference dependence utility and +and and recent more economics work is + + align:start position:0% +and and recent more economics work is + + + align:start position:0% +and and recent more economics work is +what really matters is + + align:start position:0% +what really matters is + + + align:start position:0% +what really matters is +expectations so what do you expect + + align:start position:0% +expectations so what do you expect + + + align:start position:0% +expectations so what do you expect +to consume or to have and so on that + + align:start position:0% +to consume or to have and so on that + + + align:start position:0% +to consume or to have and so on that +matters that sometimes coincides with + + align:start position:0% +matters that sometimes coincides with + + + align:start position:0% +matters that sometimes coincides with +the status quo + + align:start position:0% +the status quo + + + align:start position:0% +the status quo +for example if you have a house the + + align:start position:0% +for example if you have a house the + + + align:start position:0% +for example if you have a house the +status quo is that you have a house you + + align:start position:0% +status quo is that you have a house you + + + align:start position:0% +status quo is that you have a house you +probably assume that you have a house in + + align:start position:0% +probably assume that you have a house in + + + align:start position:0% +probably assume that you have a house in +the future + + align:start position:0% +the future + + + align:start position:0% +the future +uh these things coincide if you think + + align:start position:0% +uh these things coincide if you think + + + align:start position:0% +uh these things coincide if you think +about wages et cetera what seems to + + align:start position:0% +about wages et cetera what seems to + + + align:start position:0% +about wages et cetera what seems to +matter often is not so much how + + align:start position:0% +matter often is not so much how + + + align:start position:0% +matter often is not so much how +much what people's wages are right now + + align:start position:0% +much what people's wages are right now + + + align:start position:0% +much what people's wages are right now +what matters is like what wage gains and + + align:start position:0% +what matters is like what wage gains and + + + align:start position:0% +what matters is like what wage gains and +so on do they expect to + + align:start position:0% +so on do they expect to + + + align:start position:0% +so on do they expect to +receive in the future and they evaluate + + align:start position:0% +receive in the future and they evaluate + + + align:start position:0% +receive in the future and they evaluate +their future their their outcomes in the + + align:start position:0% +their future their their outcomes in the + + + align:start position:0% +their future their their outcomes in the +future + + align:start position:0% +future + + + align:start position:0% +future +uh not necessarily to like the current + + align:start position:0% +uh not necessarily to like the current + + + align:start position:0% +uh not necessarily to like the current +wage but rather what they expect they + + align:start position:0% +wage but rather what they expect they + + + align:start position:0% +wage but rather what they expect they +would get + + align:start position:0% +would get + + + align:start position:0% +would get +in the future okay and so here's an + + align:start position:0% +in the future okay and so here's an + + + align:start position:0% +in the future okay and so here's an +example + + align:start position:0% +example + + + align:start position:0% +example +and you'll have some problem sets + + align:start position:0% +and you'll have some problem sets + + + align:start position:0% +and you'll have some problem sets +questions again this is problem set + + align:start position:0% +questions again this is problem set + + + align:start position:0% +questions again this is problem set +three + + align:start position:0% +three + + + align:start position:0% +three +which is not posted yet but but will be + + align:start position:0% +which is not posted yet but but will be + + + align:start position:0% +which is not posted yet but but will be +uh of that kind + + align:start position:0% +uh of that kind + + + align:start position:0% +uh of that kind +which is you might have like reference + + align:start position:0% +which is you might have like reference + + + align:start position:0% +which is you might have like reference +dependent utility over + + align:start position:0% +dependent utility over + + + align:start position:0% +dependent utility over +uh this is just a very simple example + + align:start position:0% +uh this is just a very simple example + + + align:start position:0% +uh this is just a very simple example +over shirts and money so you have + + align:start position:0% +over shirts and money so you have + + + align:start position:0% +over shirts and money so you have +essentially two different domains you + + align:start position:0% +essentially two different domains you + + + align:start position:0% +essentially two different domains you +have essentially losses and gains over + + align:start position:0% +have essentially losses and gains over + + + align:start position:0% +have essentially losses and gains over +both of those domains + + align:start position:0% +both of those domains + + + align:start position:0% +both of those domains +you have a reference point which is rs + + align:start position:0% +you have a reference point which is rs + + + align:start position:0% +you have a reference point which is rs +is how many shirts you might have you + + align:start position:0% +is how many shirts you might have you + + + align:start position:0% +is how many shirts you might have you +have a reference point rm how much money + + align:start position:0% +have a reference point rm how much money + + + align:start position:0% +have a reference point rm how much money +you might have + + align:start position:0% +you might have + + + align:start position:0% +you might have +now what's important here is that + + align:start position:0% +now what's important here is that + + + align:start position:0% +now what's important here is that +essentially when you think about buying + + align:start position:0% +essentially when you think about buying + + + align:start position:0% +essentially when you think about buying +a shirt + + align:start position:0% +a shirt + + + align:start position:0% +a shirt +or or selling a shirt there's going to + + align:start position:0% +or or selling a shirt there's going to + + + align:start position:0% +or or selling a shirt there's going to +be two dimensions + + align:start position:0% +be two dimensions + + + align:start position:0% +be two dimensions +which you have to sort of consider if + + align:start position:0% +which you have to sort of consider if + + + align:start position:0% +which you have to sort of consider if +and when you think about the endowment + + align:start position:0% +and when you think about the endowment + + + align:start position:0% +and when you think about the endowment +effect of mugs and so on + + align:start position:0% +effect of mugs and so on + + + align:start position:0% +effect of mugs and so on +you have to consider not only + + align:start position:0% +you have to consider not only + + + align:start position:0% +you have to consider not only +the losses on gains and shirts but also + + align:start position:0% +the losses on gains and shirts but also + + + align:start position:0% +the losses on gains and shirts but also +the losses can gains in money + + align:start position:0% +the losses can gains in money + + + align:start position:0% +the losses can gains in money +so that's to say if you're trying to buy + + align:start position:0% +so that's to say if you're trying to buy + + + align:start position:0% +so that's to say if you're trying to buy +something you're going to get like a + + align:start position:0% +something you're going to get like a + + + align:start position:0% +something you're going to get like a +gain in shirts relative to the reference + + align:start position:0% +gain in shirts relative to the reference + + + align:start position:0% +gain in shirts relative to the reference +point if it's unexpected + + align:start position:0% +point if it's unexpected + + + align:start position:0% +point if it's unexpected +but you'll also have a loss in money + + align:start position:0% +but you'll also have a loss in money + + + align:start position:0% +but you'll also have a loss in money +similarly if you're going to like sell a + + align:start position:0% +similarly if you're going to like sell a + + + align:start position:0% +similarly if you're going to like sell a +shirt you're going to have like a + + align:start position:0% +shirt you're going to have like a + + + align:start position:0% +shirt you're going to have like a +loss in shirts but a gain and money on + + align:start position:0% +loss in shirts but a gain and money on + + + align:start position:0% +loss in shirts but a gain and money on +these things and interact + + align:start position:0% +these things and interact + + + align:start position:0% +these things and interact +now what's the value function the value + + align:start position:0% +now what's the value function the value + + + align:start position:0% +now what's the value function the value +function as i said before it's usually + + align:start position:0% +function as i said before it's usually + + + align:start position:0% +function as i said before it's usually +concave in the gain domain and convex in + + align:start position:0% +concave in the gain domain and convex in + + + align:start position:0% +concave in the gain domain and convex in +the in the last domain + + align:start position:0% +the in the last domain + + + align:start position:0% +the in the last domain +there's a kinkex zero it's deeper on the + + align:start position:0% +there's a kinkex zero it's deeper on the + + + align:start position:0% +there's a kinkex zero it's deeper on the +left uh then on the right usually we + + align:start position:0% +left uh then on the right usually we + + + align:start position:0% +left uh then on the right usually we +think + + align:start position:0% +think + + + align:start position:0% +think +uh the relative slope is about like two + + align:start position:0% +uh the relative slope is about like two + + + align:start position:0% +uh the relative slope is about like two +2.5 + + align:start position:0% +2.5 + + + align:start position:0% +2.5 +okay so um so one version of that would + + align:start position:0% +okay so um so one version of that would + + + align:start position:0% +okay so um so one version of that would +be uh + + align:start position:0% +be uh + + + align:start position:0% +be uh +this function that i wrote down again + + align:start position:0% +this function that i wrote down again + + + align:start position:0% +this function that i wrote down again +there will be some + + align:start position:0% +there will be some + + + align:start position:0% +there will be some +problem such questions etc sort of to + + align:start position:0% +problem such questions etc sort of to + + + align:start position:0% +problem such questions etc sort of to +clarify uh that + + align:start position:0% +clarify uh that + + + align:start position:0% +clarify uh that +but one key question here is then uh + + align:start position:0% +but one key question here is then uh + + + align:start position:0% +but one key question here is then uh +what are the different domains and + + align:start position:0% +what are the different domains and + + + align:start position:0% +what are the different domains and +that's kind of like a question like of + + align:start position:0% +that's kind of like a question like of + + + align:start position:0% +that's kind of like a question like of +mental accounting we'll get to this like + + align:start position:0% +mental accounting we'll get to this like + + + align:start position:0% +mental accounting we'll get to this like +in the second half of the course + + align:start position:0% +in the second half of the course + + + align:start position:0% +in the second half of the course +the question kind of like what are the + + align:start position:0% +the question kind of like what are the + + + align:start position:0% +the question kind of like what are the +different categories do you have like + + align:start position:0% +different categories do you have like + + + align:start position:0% +different categories do you have like +shirts do you have like + + align:start position:0% +shirts do you have like + + + align:start position:0% +shirts do you have like +uh pants uh sweaters or is it just for + + align:start position:0% +uh pants uh sweaters or is it just for + + + align:start position:0% +uh pants uh sweaters or is it just for +clothes overall + + align:start position:0% +clothes overall + + + align:start position:0% +clothes overall +um or like when you think about like + + align:start position:0% +um or like when you think about like + + + align:start position:0% +um or like when you think about like +earnings and uh consumption et cetera is + + align:start position:0% +earnings and uh consumption et cetera is + + + align:start position:0% +earnings and uh consumption et cetera is +it daily consumption is it weekly + + align:start position:0% +it daily consumption is it weekly + + + align:start position:0% +it daily consumption is it weekly +consumption is it monthly consumption + + align:start position:0% +consumption is it monthly consumption + + + align:start position:0% +consumption is it monthly consumption +so there's lots of questions on like how + + align:start position:0% +so there's lots of questions on like how + + + align:start position:0% +so there's lots of questions on like how +to exactly specify this utility function + + align:start position:0% +to exactly specify this utility function + + + align:start position:0% +to exactly specify this utility function +these questions are mostly um unanswered + + align:start position:0% +these questions are mostly um unanswered + + + align:start position:0% +these questions are mostly um unanswered +in the literature so for now for us in + + align:start position:0% +in the literature so for now for us in + + + align:start position:0% +in the literature so for now for us in +our purposes + + align:start position:0% +our purposes + + + align:start position:0% +our purposes +we're going to essentially assume there + + align:start position:0% +we're going to essentially assume there + + + align:start position:0% +we're going to essentially assume there +is a value function given and then + + align:start position:0% +is a value function given and then + + + align:start position:0% +is a value function given and then +sort of work with with that + + align:start position:0% + + + + align:start position:0% + +any questions on that + + align:start position:0% + + + + align:start position:0% + +okay great so now we're going to talk + + align:start position:0% +okay great so now we're going to talk + + + align:start position:0% +okay great so now we're going to talk +about the number of different + + align:start position:0% +about the number of different + + + align:start position:0% +about the number of different +applications we talked a little bit + + align:start position:0% +applications we talked a little bit + + + align:start position:0% +applications we talked a little bit +about already + + align:start position:0% +about already + + + align:start position:0% +about already +about the endowment effect and about + + align:start position:0% +about the endowment effect and about + + + align:start position:0% +about the endowment effect and about +insurance i'm going to skip this + + align:start position:0% +insurance i'm going to skip this + + + align:start position:0% +insurance i'm going to skip this +um there's some of this already in in + + align:start position:0% +um there's some of this already in in + + + align:start position:0% +um there's some of this already in in +recitation and the problem sets + + align:start position:0% +recitation and the problem sets + + + align:start position:0% +recitation and the problem sets +we're going to particularly talk about + + align:start position:0% +we're going to particularly talk about + + + align:start position:0% +we're going to particularly talk about +labor supply and employment decisions + + align:start position:0% +labor supply and employment decisions + + + align:start position:0% +labor supply and employment decisions +essentially how much do people + + align:start position:0% +essentially how much do people + + + align:start position:0% +essentially how much do people +like to work in is effort or people's + + align:start position:0% +like to work in is effort or people's + + + align:start position:0% +like to work in is effort or people's +work decisions are they reference + + align:start position:0% +work decisions are they reference + + + align:start position:0% +work decisions are they reference +dependent + + align:start position:0% +dependent + + + align:start position:0% +dependent +uh we're gonna talk about finances what + + align:start position:0% +uh we're gonna talk about finances what + + + align:start position:0% +uh we're gonna talk about finances what +was mentioned last time already about + + align:start position:0% +was mentioned last time already about + + + align:start position:0% +was mentioned last time already about +investment decisions when do people sell + + align:start position:0% +investment decisions when do people sell + + + align:start position:0% +investment decisions when do people sell +and buy stocks we're going to talk about + + align:start position:0% +and buy stocks we're going to talk about + + + align:start position:0% +and buy stocks we're going to talk about +housing when do people decide to sell or + + align:start position:0% +housing when do people decide to sell or + + + align:start position:0% +housing when do people decide to sell or +buy a solar house and at what price + + align:start position:0% +buy a solar house and at what price + + + align:start position:0% +buy a solar house and at what price +uh we're gonna talk about sports in + + align:start position:0% +uh we're gonna talk about sports in + + + align:start position:0% +uh we're gonna talk about sports in +particular marathon running uh + + align:start position:0% +particular marathon running uh + + + align:start position:0% +particular marathon running uh +and golf um uh and a little bit about + + align:start position:0% +and golf um uh and a little bit about + + + align:start position:0% +and golf um uh and a little bit about +this + + align:start position:0% +this + + + align:start position:0% +this +some papers in domestic violence we're + + align:start position:0% +some papers in domestic violence we're + + + align:start position:0% +some papers in domestic violence we're +gonna talk very briefly about and then + + align:start position:0% +gonna talk very briefly about and then + + + align:start position:0% +gonna talk very briefly about and then +we talk a little bit about firms how do + + align:start position:0% +we talk a little bit about firms how do + + + align:start position:0% +we talk a little bit about firms how do +firms think about pricing + + align:start position:0% +firms think about pricing + + + align:start position:0% +firms think about pricing +um uh and so on and what what is sort of + + align:start position:0% +um uh and so on and what what is sort of + + + align:start position:0% +um uh and so on and what what is sort of +like the market response to + + align:start position:0% +like the market response to + + + align:start position:0% +like the market response to +to reference dependence that's to say + + align:start position:0% +to reference dependence that's to say + + + align:start position:0% +to reference dependence that's to say +given that we know there's lots of + + align:start position:0% +given that we know there's lots of + + + align:start position:0% +given that we know there's lots of +reference dependence on the world + + align:start position:0% +reference dependence on the world + + + align:start position:0% +reference dependence on the world +uh how should we now as a firm or like + + align:start position:0% +uh how should we now as a firm or like + + + align:start position:0% +uh how should we now as a firm or like +uh + + align:start position:0% +uh + + + align:start position:0% +uh +uh treating other people how should we + + align:start position:0% +uh treating other people how should we + + + align:start position:0% +uh treating other people how should we +think about um how does that affect our + + align:start position:0% +think about um how does that affect our + + + align:start position:0% +think about um how does that affect our +our own behavior + + align:start position:0% +our own behavior + + + align:start position:0% +our own behavior +or how maybe firms interact with us okay + + align:start position:0% +or how maybe firms interact with us okay + + + align:start position:0% +or how maybe firms interact with us okay +so let's start with um a labor supply + + align:start position:0% +so let's start with um a labor supply + + + align:start position:0% +so let's start with um a labor supply +let's start with a very simple + + align:start position:0% +let's start with a very simple + + + align:start position:0% +let's start with a very simple +um example suppose there's a worker in + + align:start position:0% +um example suppose there's a worker in + + + align:start position:0% +um example suppose there's a worker in +the following situation + + align:start position:0% +the following situation + + + align:start position:0% +the following situation +she can work freely choose how many + + align:start position:0% +she can work freely choose how many + + + align:start position:0% +she can work freely choose how many +hours she works every day + + align:start position:0% +hours she works every day + + + align:start position:0% +hours she works every day +and there are frequent temporary changes + + align:start position:0% +and there are frequent temporary changes + + + align:start position:0% +and there are frequent temporary changes +in her hourly + + align:start position:0% +in her hourly + + + align:start position:0% +in her hourly +wage now there's different relationships + + align:start position:0% +wage now there's different relationships + + + align:start position:0% +wage now there's different relationships +between + + align:start position:0% +between + + + align:start position:0% +between +wages and hours per day you could always + + align:start position:0% +wages and hours per day you could always + + + align:start position:0% +wages and hours per day you could always +work the same + + align:start position:0% +work the same + + + align:start position:0% +work the same +number of hours you could work more + + align:start position:0% +number of hours you could work more + + + align:start position:0% +number of hours you could work more +hours on the days when wages are high + + align:start position:0% +hours on the days when wages are high + + + align:start position:0% +hours on the days when wages are high +or you could work a few hours and days + + align:start position:0% +or you could work a few hours and days + + + align:start position:0% +or you could work a few hours and days +when the wages are high + + align:start position:0% +when the wages are high + + + align:start position:0% +when the wages are high +what are sort of standard theory say + + align:start position:0% +what are sort of standard theory say + + + align:start position:0% +what are sort of standard theory say +what should you do + + align:start position:0% + + + + align:start position:0% + +yes two two why is that um + + align:start position:0% +yes two two why is that um + + + align:start position:0% +yes two two why is that um +because that maximizes your expected + + align:start position:0% +because that maximizes your expected + + + align:start position:0% +because that maximizes your expected +value + + align:start position:0% +value + + + align:start position:0% +value +for time right so if if hours are + + align:start position:0% +for time right so if if hours are + + + align:start position:0% +for time right so if if hours are +effortful you usually don't like to work + + align:start position:0% +effortful you usually don't like to work + + + align:start position:0% +effortful you usually don't like to work +you should work during the hours when uh + + align:start position:0% +you should work during the hours when uh + + + align:start position:0% +you should work during the hours when uh +uh + + align:start position:0% +uh + + + align:start position:0% +uh +when your payment is the largest uh + + align:start position:0% +when your payment is the largest uh + + + align:start position:0% +when your payment is the largest uh +that's right so + + align:start position:0% +that's right so + + + align:start position:0% +that's right so +what about option number one why might + + align:start position:0% +what about option number one why might + + + align:start position:0% +what about option number one why might +option number one + + align:start position:0% +option number one + + + align:start position:0% +option number one +be optimal so what you're saying is + + align:start position:0% +be optimal so what you're saying is + + + align:start position:0% +be optimal so what you're saying is +exactly right uh depends a little bit on + + align:start position:0% +exactly right uh depends a little bit on + + + align:start position:0% +exactly right uh depends a little bit on +on something else and what is that + + align:start position:0% +on something else and what is that + + + align:start position:0% +on something else and what is that +like why might you choose number one + + align:start position:0% +like why might you choose number one + + + align:start position:0% +like why might you choose number one +anyway + + align:start position:0% +anyway + + + align:start position:0% +anyway +um habit farming is nice + + align:start position:0% +um habit farming is nice + + + align:start position:0% +um habit farming is nice +yeah there could be sort of habits + + align:start position:0% +yeah there could be sort of habits + + + align:start position:0% +yeah there could be sort of habits +exactly or it could just be that it's + + align:start position:0% +exactly or it could just be that it's + + + align:start position:0% +exactly or it could just be that it's +really effortful to work like 12 hours + + align:start position:0% +really effortful to work like 12 hours + + + align:start position:0% +really effortful to work like 12 hours +in one day maybe there's like kids at + + align:start position:0% +in one day maybe there's like kids at + + + align:start position:0% +in one day maybe there's like kids at +home or maybe there's like you know it's + + align:start position:0% +home or maybe there's like you know it's + + + align:start position:0% +home or maybe there's like you know it's +just really + + align:start position:0% +just really + + + align:start position:0% +just really +tedious to work at some point you just + + align:start position:0% +tedious to work at some point you just + + + align:start position:0% +tedious to work at some point you just +want to go home and do other stuff + + align:start position:0% +want to go home and do other stuff + + + align:start position:0% +want to go home and do other stuff +so it could just be that working beyond + + align:start position:0% +so it could just be that working beyond + + + align:start position:0% +so it could just be that working beyond +you know like say eight or nine hours + + align:start position:0% +you know like say eight or nine hours + + + align:start position:0% +you know like say eight or nine hours +per day is really tough to do + + align:start position:0% +per day is really tough to do + + + align:start position:0% +per day is really tough to do +so then you might say i'm always going + + align:start position:0% +so then you might say i'm always going + + + align:start position:0% +so then you might say i'm always going +to work eight hours i'd love to work + + align:start position:0% +to work eight hours i'd love to work + + + align:start position:0% +to work eight hours i'd love to work +more + + align:start position:0% +more + + + align:start position:0% +more +uh but that's difficult to do so + + align:start position:0% +uh but that's difficult to do so + + + align:start position:0% +uh but that's difficult to do so +essentially it's just to say if the + + align:start position:0% +essentially it's just to say if the + + + align:start position:0% +essentially it's just to say if the +effort function if the + + align:start position:0% +effort function if the + + + align:start position:0% +effort function if the +effort as a resp function of hours is + + align:start position:0% +effort as a resp function of hours is + + + align:start position:0% +effort as a resp function of hours is +convex and you might sort of say + + align:start position:0% +convex and you might sort of say + + + align:start position:0% +convex and you might sort of say +keep it the same surely what you don't + + align:start position:0% +keep it the same surely what you don't + + + align:start position:0% +keep it the same surely what you don't +want to do as + + align:start position:0% +want to do as + + + align:start position:0% +want to do as +number three working few hours and days + + align:start position:0% +number three working few hours and days + + + align:start position:0% +number three working few hours and days +and wages are high + + align:start position:0% +and wages are high + + + align:start position:0% +and wages are high +unless you know effort costs are + + align:start position:0% +unless you know effort costs are + + + align:start position:0% +unless you know effort costs are +particularly high on those days so it + + align:start position:0% +particularly high on those days so it + + + align:start position:0% +particularly high on those days so it +could be that it's like really super hot + + align:start position:0% +could be that it's like really super hot + + + align:start position:0% +could be that it's like really super hot +or it could be like it's super tedious + + align:start position:0% +or it could be like it's super tedious + + + align:start position:0% +or it could be like it's super tedious +to work on those days and you might say + + align:start position:0% +to work on those days and you might say + + + align:start position:0% +to work on those days and you might say +then you don't want to do it + + align:start position:0% +then you don't want to do it + + + align:start position:0% +then you don't want to do it +but assuming that's not the case you you + + align:start position:0% +but assuming that's not the case you you + + + align:start position:0% +but assuming that's not the case you you +kind of want to avoid this because + + align:start position:0% +kind of want to avoid this because + + + align:start position:0% +kind of want to avoid this because +for the same number of hours you're + + align:start position:0% +for the same number of hours you're + + + align:start position:0% +for the same number of hours you're +going to make less money um overall + + align:start position:0% +going to make less money um overall + + + align:start position:0% +going to make less money um overall +right and sort of here's a concrete + + align:start position:0% +right and sort of here's a concrete + + + align:start position:0% +right and sort of here's a concrete +example suppose wages + + align:start position:0% +example suppose wages + + + align:start position:0% +example suppose wages +five hours an hour on day one and ten + + align:start position:0% +five hours an hour on day one and ten + + + align:start position:0% +five hours an hour on day one and ten +hours a day on day two + + align:start position:0% +hours a day on day two + + + align:start position:0% +hours a day on day two +so there's three strategies you can work + + align:start position:0% +so there's three strategies you can work + + + align:start position:0% +so there's three strategies you can work +eight hours in both days you can work + + align:start position:0% +eight hours in both days you can work + + + align:start position:0% +eight hours in both days you can work +six hours on day one nine hours on day + + align:start position:0% +six hours on day one nine hours on day + + + align:start position:0% +six hours on day one nine hours on day +two + + align:start position:0% +two + + + align:start position:0% +two +or the opposite nine hours on day one + + align:start position:0% +or the opposite nine hours on day one + + + align:start position:0% +or the opposite nine hours on day one +and six hours on on day two + + align:start position:0% +and six hours on on day two + + + align:start position:0% +and six hours on on day two +so if you do that you can do you sort of + + align:start position:0% +so if you do that you can do you sort of + + + align:start position:0% +so if you do that you can do you sort of +calculate how much that is you can + + align:start position:0% +calculate how much that is you can + + + align:start position:0% +calculate how much that is you can +essentially work eight hours on both + + align:start position:0% +essentially work eight hours on both + + + align:start position:0% +essentially work eight hours on both +days you get 120 hours you can work + + align:start position:0% +days you get 120 hours you can work + + + align:start position:0% +days you get 120 hours you can work +six hours and nine uh uh uh + + align:start position:0% +six hours and nine uh uh uh + + + align:start position:0% +six hours and nine uh uh uh +uh on on days one and two which makes + + align:start position:0% +uh on on days one and two which makes + + + align:start position:0% +uh on on days one and two which makes +120 hours + + align:start position:0% +120 hours + + + align:start position:0% +120 hours +at dollars as well or you can + + align:start position:0% +at dollars as well or you can + + + align:start position:0% +at dollars as well or you can +essentially do um the opposite which + + align:start position:0% +essentially do um the opposite which + + + align:start position:0% +essentially do um the opposite which +makes you 105 + + align:start position:0% +makes you 105 + + + align:start position:0% +makes you 105 +dollars this is what i was saying like + + align:start position:0% +dollars this is what i was saying like + + + align:start position:0% +dollars this is what i was saying like +options three doesn't make a lot of + + align:start position:0% +options three doesn't make a lot of + + + align:start position:0% +options three doesn't make a lot of +sense + + align:start position:0% +sense + + + align:start position:0% +sense +um unless effort costs are particularly + + align:start position:0% +um unless effort costs are particularly + + + align:start position:0% +um unless effort costs are particularly +high on certain days when the wages are + + align:start position:0% +high on certain days when the wages are + + + align:start position:0% +high on certain days when the wages are +high + + align:start position:0% +high + + + align:start position:0% +high +we're assuming that away for now um and + + align:start position:0% +we're assuming that away for now um and + + + align:start position:0% +we're assuming that away for now um and +so now option two + + align:start position:0% +so now option two + + + align:start position:0% +so now option two +and this is what you were saying + + align:start position:0% +and this is what you were saying + + + align:start position:0% +and this is what you were saying +essentially saves you an hour overall + + align:start position:0% +essentially saves you an hour overall + + + align:start position:0% +essentially saves you an hour overall +you work only 15 hours instead of 16 + + align:start position:0% +you work only 15 hours instead of 16 + + + align:start position:0% +you work only 15 hours instead of 16 +hours and you make the same amount of + + align:start position:0% +hours and you make the same amount of + + + align:start position:0% +hours and you make the same amount of +money + + align:start position:0% +money + + + align:start position:0% +money +now unless sort of the effort court + + align:start position:0% +now unless sort of the effort court + + + align:start position:0% +now unless sort of the effort court +unless the ninth hour is extremely + + align:start position:0% +unless the ninth hour is extremely + + + align:start position:0% +unless the ninth hour is extremely +costly for you to do you might not want + + align:start position:0% +costly for you to do you might not want + + + align:start position:0% +costly for you to do you might not want +to to do that + + align:start position:0% +to to do that + + + align:start position:0% +to to do that +okay now why might you do + + align:start position:0% +okay now why might you do + + + align:start position:0% +okay now why might you do +uh something else uh instead or what + + align:start position:0% +uh something else uh instead or what + + + align:start position:0% +uh something else uh instead or what +sort of + + align:start position:0% +sort of + + + align:start position:0% +sort of +where does reference dependence come in + + align:start position:0% +where does reference dependence come in + + + align:start position:0% +where does reference dependence come in +here + + align:start position:0% + + + + align:start position:0% + +yes i see on the high wage day that i've + + align:start position:0% +yes i see on the high wage day that i've + + + align:start position:0% +yes i see on the high wage day that i've +made more than the less waste day so i + + align:start position:0% +made more than the less waste day so i + + + align:start position:0% +made more than the less waste day so i +feel like stopping maybe + + align:start position:0% +feel like stopping maybe + + + align:start position:0% +feel like stopping maybe +and why am i why would you stop like + + align:start position:0% +and why am i why would you stop like + + + align:start position:0% +and why am i why would you stop like +what's what's what's causing you to stop + + align:start position:0% +what's what's what's causing you to stop + + + align:start position:0% +what's what's what's causing you to stop +uh + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +yeah and so yes and but + + align:start position:0% +yeah and so yes and but + + + align:start position:0% +yeah and so yes and but +so what's the what are you evaluating or + + align:start position:0% +so what's the what are you evaluating or + + + align:start position:0% +so what's the what are you evaluating or +what's the + + align:start position:0% + + + + align:start position:0% + +or what happens for example if you work + + align:start position:0% +or what happens for example if you work + + + align:start position:0% +or what happens for example if you work +only six hours on + + align:start position:0% +only six hours on + + + align:start position:0% +only six hours on +on a different day like how much do you + + align:start position:0% +on a different day like how much do you + + + align:start position:0% +on a different day like how much do you +make on the six hour day i guess which + + align:start position:0% +make on the six hour day i guess which + + + align:start position:0% +make on the six hour day i guess which +would be + + align:start position:0% +would be + + + align:start position:0% +would be +uh maybe thirty dollars right and so + + align:start position:0% + + + + align:start position:0% + +what are you comparing that to i guess + + align:start position:0% + + + + align:start position:0% + +so suppose you on average you want to + + align:start position:0% +so suppose you on average you want to + + + align:start position:0% +so suppose you on average you want to +make a certain amount of money which is + + align:start position:0% +make a certain amount of money which is + + + align:start position:0% +make a certain amount of money which is + + align:start position:0% + + + align:start position:0% +60 and so on now if on sundays you make + + align:start position:0% +60 and so on now if on sundays you make + + + align:start position:0% +60 and so on now if on sundays you make +a lot of money and on sunday you make + + align:start position:0% +a lot of money and on sunday you make + + + align:start position:0% +a lot of money and on sunday you make +very little money + + align:start position:0% +very little money + + + align:start position:0% +very little money +you might sort of evaluate that + + align:start position:0% +you might sort of evaluate that + + + align:start position:0% +you might sort of evaluate that +separately and say on that day i'm + + align:start position:0% +separately and say on that day i'm + + + align:start position:0% +separately and say on that day i'm +essentially in the last domain i'm like + + align:start position:0% +essentially in the last domain i'm like + + + align:start position:0% +essentially in the last domain i'm like +below my target or + + align:start position:0% +below my target or + + + align:start position:0% +below my target or +below my expectation and so if you + + align:start position:0% +below my expectation and so if you + + + align:start position:0% +below my expectation and so if you +evaluate your + + align:start position:0% +evaluate your + + + align:start position:0% +evaluate your +utility that way you might sort of not + + align:start position:0% +utility that way you might sort of not + + + align:start position:0% +utility that way you might sort of not +want that because it feels essentially + + align:start position:0% +want that because it feels essentially + + + align:start position:0% +want that because it feels essentially +you're below + + align:start position:0% +you're below + + + align:start position:0% +you're below +a certain threshold it feels kind of + + align:start position:0% +a certain threshold it feels kind of + + + align:start position:0% +a certain threshold it feels kind of +like a loss relative to your expectation + + align:start position:0% +like a loss relative to your expectation + + + align:start position:0% +like a loss relative to your expectation +and so on + + align:start position:0% +and so on + + + align:start position:0% +and so on +and you might be inclined to work a lot + + align:start position:0% +and you might be inclined to work a lot + + + align:start position:0% +and you might be inclined to work a lot +of hours + + align:start position:0% +of hours + + + align:start position:0% +of hours +instead on the days when you make a lot + + align:start position:0% +instead on the days when you make a lot + + + align:start position:0% +instead on the days when you make a lot +of money why might you stop + + align:start position:0% + + + + align:start position:0% + +yes you might have like a target that + + align:start position:0% +yes you might have like a target that + + + align:start position:0% +yes you might have like a target that +you expect to hit every day to cover + + align:start position:0% +you expect to hit every day to cover + + + align:start position:0% +you expect to hit every day to cover +your expenses and if you + + align:start position:0% +your expenses and if you + + + align:start position:0% +your expenses and if you +feel like working less you can still + + align:start position:0% +feel like working less you can still + + + align:start position:0% +feel like working less you can still +reach that target + + align:start position:0% + + + + align:start position:0% + +right so if your target your reference + + align:start position:0% +right so if your target your reference + + + align:start position:0% +right so if your target your reference +point is essentially a a certain number + + align:start position:0% +point is essentially a a certain number + + + align:start position:0% +point is essentially a a certain number +you might reach that target quickly + + align:start position:0% +you might reach that target quickly + + + align:start position:0% +you might reach that target quickly +because your wage is pretty high on that + + align:start position:0% +because your wage is pretty high on that + + + align:start position:0% +because your wage is pretty high on that +day + + align:start position:0% +day + + + align:start position:0% +day +now once you reach that target you might + + align:start position:0% +now once you reach that target you might + + + align:start position:0% +now once you reach that target you might +say well like now your utility function + + align:start position:0% +say well like now your utility function + + + align:start position:0% +say well like now your utility function +is relatively + + align:start position:0% +is relatively + + + align:start position:0% +is relatively +not very steep anymore relative to being + + align:start position:0% +not very steep anymore relative to being + + + align:start position:0% +not very steep anymore relative to being +in the last domain so it's like flatter + + align:start position:0% +in the last domain so it's like flatter + + + align:start position:0% +in the last domain so it's like flatter +so then you might just stop relatively + + align:start position:0% +so then you might just stop relatively + + + align:start position:0% +so then you might just stop relatively +soon because essentially any marginal + + align:start position:0% +soon because essentially any marginal + + + align:start position:0% +soon because essentially any marginal +earnings + + align:start position:0% +earnings + + + align:start position:0% +earnings +are not really valuable for you anymore + + align:start position:0% +are not really valuable for you anymore + + + align:start position:0% +are not really valuable for you anymore +okay any questions on that or comments + + align:start position:0% +okay any questions on that or comments + + + align:start position:0% +okay any questions on that or comments +so why do we want the wage changes to be + + align:start position:0% +so why do we want the wage changes to be + + + align:start position:0% +so why do we want the wage changes to be +temporary here what's an issue here when + + align:start position:0% +temporary here what's an issue here when + + + align:start position:0% +temporary here what's an issue here when +you sort of try to look at this in the + + align:start position:0% +you sort of try to look at this in the + + + align:start position:0% +you sort of try to look at this in the +data + + align:start position:0% +data + + + align:start position:0% +data +suppose i had like persistent wage + + align:start position:0% +suppose i had like persistent wage + + + align:start position:0% +suppose i had like persistent wage +changes yeah so you can have like a + + align:start position:0% +changes yeah so you can have like a + + + align:start position:0% +changes yeah so you can have like a +frame of reference + + align:start position:0% + + + + align:start position:0% + +yeah you want to kind of keep the + + align:start position:0% +yeah you want to kind of keep the + + + align:start position:0% +yeah you want to kind of keep the +reference constant so in some sense if + + align:start position:0% +reference constant so in some sense if + + + align:start position:0% +reference constant so in some sense if +wage changes are permanent + + align:start position:0% +wage changes are permanent + + + align:start position:0% +wage changes are permanent +uh then you get essentially income + + align:start position:0% +uh then you get essentially income + + + align:start position:0% +uh then you get essentially income +effects you'll be a lot richer overall + + align:start position:0% +effects you'll be a lot richer overall + + + align:start position:0% +effects you'll be a lot richer overall +if they're only temporary essentially + + align:start position:0% +if they're only temporary essentially + + + align:start position:0% +if they're only temporary essentially +you can sort of argue that essentially + + align:start position:0% +you can sort of argue that essentially + + + align:start position:0% +you can sort of argue that essentially +your expectation should be the same + + align:start position:0% +your expectation should be the same + + + align:start position:0% +your expectation should be the same +and once you reach once you have a lot + + align:start position:0% +and once you reach once you have a lot + + + align:start position:0% +and once you reach once you have a lot +more money then your classical model + + align:start position:0% +more money then your classical model + + + align:start position:0% +more money then your classical model +should actually say that there should be + + align:start position:0% +should actually say that there should be + + + align:start position:0% +should actually say that there should be +income effects + + align:start position:0% +income effects + + + align:start position:0% +income effects +the neoclassical model only says + + align:start position:0% +the neoclassical model only says + + + align:start position:0% +the neoclassical model only says +essentially the inner classical model + + align:start position:0% +essentially the inner classical model + + + align:start position:0% +essentially the inner classical model +says + + align:start position:0% +says + + + align:start position:0% +says +you should essentially aggregate all of + + align:start position:0% +you should essentially aggregate all of + + + align:start position:0% +you should essentially aggregate all of +your income and say it doesn't really + + align:start position:0% +your income and say it doesn't really + + + align:start position:0% +your income and say it doesn't really +matter like whether you earn it in + + align:start position:0% +matter like whether you earn it in + + + align:start position:0% +matter like whether you earn it in +monday or tuesday wednesday or thursday + + align:start position:0% +monday or tuesday wednesday or thursday + + + align:start position:0% +monday or tuesday wednesday or thursday +you should look at like how much are you + + align:start position:0% +you should look at like how much are you + + + align:start position:0% +you should look at like how much are you +earning overall depending whether you + + align:start position:0% +earning overall depending whether you + + + align:start position:0% +earning overall depending whether you +earn + + align:start position:0% +earn + + + align:start position:0% +earn +sufficiently much um uh you're gonna + + align:start position:0% +sufficiently much um uh you're gonna + + + align:start position:0% +sufficiently much um uh you're gonna +work fewer or more hours + + align:start position:0% +work fewer or more hours + + + align:start position:0% +work fewer or more hours +now if you earn like a lot because your + + align:start position:0% +now if you earn like a lot because your + + + align:start position:0% +now if you earn like a lot because your +wages doubles or whatever you might + + align:start position:0% +wages doubles or whatever you might + + + align:start position:0% +wages doubles or whatever you might +actually work few hours + + align:start position:0% +actually work few hours + + + align:start position:0% +actually work few hours +not because you reach a reference point + + align:start position:0% +not because you reach a reference point + + + align:start position:0% +not because you reach a reference point +on a given day it's just because you got + + align:start position:0% +on a given day it's just because you got + + + align:start position:0% +on a given day it's just because you got +a lot richer and then you decide it's + + align:start position:0% +a lot richer and then you decide it's + + + align:start position:0% +a lot richer and then you decide it's +not worth for you to work that much + + align:start position:0% +not worth for you to work that much + + + align:start position:0% +not worth for you to work that much +so we're kind of trying to avoid that + + align:start position:0% +so we're kind of trying to avoid that + + + align:start position:0% +so we're kind of trying to avoid that +we're trying to have only permanent + + align:start position:0% +we're trying to have only permanent + + + align:start position:0% +we're trying to have only permanent +temporary changes which is to say + + align:start position:0% +temporary changes which is to say + + + align:start position:0% +temporary changes which is to say +forgiven wealth overall um + + align:start position:0% +forgiven wealth overall um + + + align:start position:0% +forgiven wealth overall um +on any given day it shouldn't matter + + align:start position:0% +on any given day it shouldn't matter + + + align:start position:0% +on any given day it shouldn't matter +whether you earn the money on monday or + + align:start position:0% +whether you earn the money on monday or + + + align:start position:0% +whether you earn the money on monday or +on tuesday + + align:start position:0% +on tuesday + + + align:start position:0% +on tuesday +so essentially if the wage happens to be + + align:start position:0% +so essentially if the wage happens to be + + + align:start position:0% +so essentially if the wage happens to be +really high on tuesday you should be + + align:start position:0% +really high on tuesday you should be + + + align:start position:0% +really high on tuesday you should be +working more earning more on tuesday as + + align:start position:0% +working more earning more on tuesday as + + + align:start position:0% +working more earning more on tuesday as +opposed to on monday + + align:start position:0% +opposed to on monday + + + align:start position:0% +opposed to on monday +uh now what i was saying is if you + + align:start position:0% +uh now what i was saying is if you + + + align:start position:0% +uh now what i was saying is if you +reference the pendant you might actually + + align:start position:0% +reference the pendant you might actually + + + align:start position:0% +reference the pendant you might actually +care about this you might care about on + + align:start position:0% +care about this you might care about on + + + align:start position:0% +care about this you might care about on +monday you didn't reach your target + + align:start position:0% +monday you didn't reach your target + + + align:start position:0% +monday you didn't reach your target +therefore you want to work more + + align:start position:0% +therefore you want to work more + + + align:start position:0% +therefore you want to work more +on tuesday you reach your target very + + align:start position:0% +on tuesday you reach your target very + + + align:start position:0% +on tuesday you reach your target very +quickly and you work + + align:start position:0% +quickly and you work + + + align:start position:0% +quickly and you work +uh uh less even though the wage is + + align:start position:0% +uh uh less even though the wage is + + + align:start position:0% +uh uh less even though the wage is +actually really high + + align:start position:0% +actually really high + + + align:start position:0% +actually really high +okay now + + align:start position:0% + + + + align:start position:0% + +strategy one might be optimal even in + + align:start position:0% +strategy one might be optimal even in + + + align:start position:0% +strategy one might be optimal even in +the neoclassical model if effort costs + + align:start position:0% +the neoclassical model if effort costs + + + align:start position:0% +the neoclassical model if effort costs +uh are convex this is what i was saying + + align:start position:0% +uh are convex this is what i was saying + + + align:start position:0% +uh are convex this is what i was saying +is if it's really sort of costly for you + + align:start position:0% +is if it's really sort of costly for you + + + align:start position:0% +is if it's really sort of costly for you +to work nine hours you might say i + + align:start position:0% +to work nine hours you might say i + + + align:start position:0% +to work nine hours you might say i +always work like eight hours i wanna + + align:start position:0% +always work like eight hours i wanna + + + align:start position:0% +always work like eight hours i wanna +have a certain amount of money for my + + align:start position:0% +have a certain amount of money for my + + + align:start position:0% +have a certain amount of money for my +children and so on + + align:start position:0% +children and so on + + + align:start position:0% +children and so on +um so the extra hour if that's really + + align:start position:0% +um so the extra hour if that's really + + + align:start position:0% +um so the extra hour if that's really +really painful you might not want to do + + align:start position:0% +really painful you might not want to do + + + align:start position:0% +really painful you might not want to do +that + + align:start position:0% +that + + + align:start position:0% +that +uh we don't think that's necessarily the + + align:start position:0% +uh we don't think that's necessarily the + + + align:start position:0% +uh we don't think that's necessarily the +case in in so many + + align:start position:0% +case in in so many + + + align:start position:0% +case in in so many +uh situations um the question is like + + align:start position:0% +uh situations um the question is like + + + align:start position:0% +uh situations um the question is like +can we really say that strategy + + align:start position:0% +can we really say that strategy + + + align:start position:0% +can we really say that strategy +three that's the strategy of doing the + + align:start position:0% +three that's the strategy of doing the + + + align:start position:0% +three that's the strategy of doing the +opposite of working like essentially a + + align:start position:0% +opposite of working like essentially a + + + align:start position:0% +opposite of working like essentially a +lot of hours and wages are low and few + + align:start position:0% +lot of hours and wages are low and few + + + align:start position:0% +lot of hours and wages are low and few +hours + + align:start position:0% +hours + + + align:start position:0% +hours +when wages are high can we really say + + align:start position:0% +when wages are high can we really say + + + align:start position:0% +when wages are high can we really say +it's a mistake well it depends on kind + + align:start position:0% +it's a mistake well it depends on kind + + + align:start position:0% +it's a mistake well it depends on kind +of like whether the effort costs are + + align:start position:0% +of like whether the effort costs are + + + align:start position:0% +of like whether the effort costs are +correlated with wages so if cab drivers + + align:start position:0% +correlated with wages so if cab drivers + + + align:start position:0% +correlated with wages so if cab drivers +for example make really high wages on + + align:start position:0% +for example make really high wages on + + + align:start position:0% +for example make really high wages on +some days and low wages on + + align:start position:0% +some days and low wages on + + + align:start position:0% +some days and low wages on +other days it could just be on low low + + align:start position:0% +other days it could just be on low low + + + align:start position:0% +other days it could just be on low low +uh + + align:start position:0% +uh + + + align:start position:0% +uh +wage day it's really um uh it's much + + align:start position:0% +wage day it's really um uh it's much + + + align:start position:0% +wage day it's really um uh it's much +less effortful to drive around + + align:start position:0% +less effortful to drive around + + + align:start position:0% +less effortful to drive around +so you would do like more hours it turns + + align:start position:0% +so you would do like more hours it turns + + + align:start position:0% +so you would do like more hours it turns +out when you actually ask + + align:start position:0% +out when you actually ask + + + align:start position:0% +out when you actually ask +a cab drivers they actually prefer a + + align:start position:0% +a cab drivers they actually prefer a + + + align:start position:0% +a cab drivers they actually prefer a +busy day is actually preferred when + + align:start position:0% +busy day is actually preferred when + + + align:start position:0% +busy day is actually preferred when +they're customers as opposed to just + + align:start position:0% +they're customers as opposed to just + + + align:start position:0% +they're customers as opposed to just +driving around and looking for people so + + align:start position:0% +driving around and looking for people so + + + align:start position:0% +driving around and looking for people so +we don't think that's actually true + + align:start position:0% +we don't think that's actually true + + + align:start position:0% +we don't think that's actually true +but in principle you would have to sort + + align:start position:0% +but in principle you would have to sort + + + align:start position:0% +but in principle you would have to sort +of think about uh that + + align:start position:0% +of think about uh that + + + align:start position:0% +of think about uh that +now uh there's a long literature uh + + align:start position:0% +now uh there's a long literature uh + + + align:start position:0% +now uh there's a long literature uh +starting with camera at all on + + align:start position:0% +starting with camera at all on + + + align:start position:0% +starting with camera at all on +uh cab drivers a lot of that essentially + + align:start position:0% +uh cab drivers a lot of that essentially + + + align:start position:0% +uh cab drivers a lot of that essentially +is pre + + align:start position:0% +is pre + + + align:start position:0% +is pre +uber like uh collecting trip sheets um + + align:start position:0% +uber like uh collecting trip sheets um + + + align:start position:0% +uber like uh collecting trip sheets um +from + + align:start position:0% +from + + + align:start position:0% +from +cab drivers now there's lots of like + + align:start position:0% +cab drivers now there's lots of like + + + align:start position:0% +cab drivers now there's lots of like +uber data that's like essentially much + + align:start position:0% +uber data that's like essentially much + + + align:start position:0% +uber data that's like essentially much +more powerful in some ways + + align:start position:0% +more powerful in some ways + + + align:start position:0% +more powerful in some ways +so there will be probably more papers + + align:start position:0% +so there will be probably more papers + + + align:start position:0% +so there will be probably more papers +using uber and lyft etc data on that + + align:start position:0% +using uber and lyft etc data on that + + + align:start position:0% +using uber and lyft etc data on that +um but what camera doll did at the time + + align:start position:0% +um but what camera doll did at the time + + + align:start position:0% +um but what camera doll did at the time +was + + align:start position:0% +was + + + align:start position:0% +was +they essentially looked at a typical cab + + align:start position:0% +they essentially looked at a typical cab + + + align:start position:0% +they essentially looked at a typical cab +drivers that rent their cab for 12 hour + + align:start position:0% +drivers that rent their cab for 12 hour + + + align:start position:0% +drivers that rent their cab for 12 hour +periods for a fixed fee + + align:start position:0% +periods for a fixed fee + + + align:start position:0% +periods for a fixed fee +and within this 12 hour window a driver + + align:start position:0% +and within this 12 hour window a driver + + + align:start position:0% +and within this 12 hour window a driver +can choose the hours freely so you just + + align:start position:0% +can choose the hours freely so you just + + + align:start position:0% +can choose the hours freely so you just +get your cab that's not yours you rent + + align:start position:0% +get your cab that's not yours you rent + + + align:start position:0% +get your cab that's not yours you rent +it for the day and then you can + + align:start position:0% +it for the day and then you can + + + align:start position:0% +it for the day and then you can +essentially choose how many hours you + + align:start position:0% +essentially choose how many hours you + + + align:start position:0% +essentially choose how many hours you +want to work + + align:start position:0% +want to work + + + align:start position:0% +want to work +and their wages how much money they make + + align:start position:0% +and their wages how much money they make + + + align:start position:0% +and their wages how much money they make +in any given hour varies by a lot + + align:start position:0% +in any given hour varies by a lot + + + align:start position:0% +in any given hour varies by a lot +there's like you know uh the weather + + align:start position:0% +there's like you know uh the weather + + + align:start position:0% +there's like you know uh the weather +varies there's subway breakdowns + + align:start position:0% +varies there's subway breakdowns + + + align:start position:0% +varies there's subway breakdowns +conferences and so on and so forth + + align:start position:0% +conferences and so on and so forth + + + align:start position:0% +conferences and so on and so forth +there's lots of variation in how much + + align:start position:0% +there's lots of variation in how much + + + align:start position:0% +there's lots of variation in how much +money you make on a given + + align:start position:0% +money you make on a given + + + align:start position:0% +money you make on a given +day so then they have like trip sheets + + align:start position:0% +day so then they have like trip sheets + + + align:start position:0% +day so then they have like trip sheets +that look at like how long + + align:start position:0% +that look at like how long + + + align:start position:0% +that look at like how long +cab drivers work and their overall + + align:start position:0% +cab drivers work and their overall + + + align:start position:0% +cab drivers work and their overall +earnings and so they can essentially + + align:start position:0% +earnings and so they can essentially + + + align:start position:0% +earnings and so they can essentially +back out the wages from + + align:start position:0% +back out the wages from + + + align:start position:0% +back out the wages from +from each day and then look at like how + + align:start position:0% +from each day and then look at like how + + + align:start position:0% +from each day and then look at like how +much do people work on uh + + align:start position:0% +much do people work on uh + + + align:start position:0% +much do people work on uh +days when wages are high versus wages + + align:start position:0% +days when wages are high versus wages + + + align:start position:0% +days when wages are high versus wages +are days when wages + + align:start position:0% +are days when wages + + + align:start position:0% +are days when wages +are low and then they essentially find + + align:start position:0% +are low and then they essentially find + + + align:start position:0% +are low and then they essentially find +the basic finding and that's a finding + + align:start position:0% +the basic finding and that's a finding + + + align:start position:0% +the basic finding and that's a finding +that's sort of been contested in the + + align:start position:0% +that's sort of been contested in the + + + align:start position:0% +that's sort of been contested in the +literature and many people are found + + align:start position:0% +literature and many people are found + + + align:start position:0% +literature and many people are found +are confirmed subsequently or and others + + align:start position:0% +are confirmed subsequently or and others + + + align:start position:0% +are confirmed subsequently or and others +have not but i think eventually people + + align:start position:0% +have not but i think eventually people + + + align:start position:0% +have not but i think eventually people +have sort of + + align:start position:0% +have sort of + + + align:start position:0% +have sort of +settled on this hours are negatively + + align:start position:0% +settled on this hours are negatively + + + align:start position:0% +settled on this hours are negatively +correlated with wages so when wages in + + align:start position:0% +correlated with wages so when wages in + + + align:start position:0% +correlated with wages so when wages in +particular are unexpectedly high + + align:start position:0% +particular are unexpectedly high + + + align:start position:0% +particular are unexpectedly high +uh cap drivers tend to work a few hours + + align:start position:0% +uh cap drivers tend to work a few hours + + + align:start position:0% +uh cap drivers tend to work a few hours +and again the and this is like not for + + align:start position:0% +and again the and this is like not for + + + align:start position:0% +and again the and this is like not for +permanent changes but for transitory + + align:start position:0% +permanent changes but for transitory + + + align:start position:0% +permanent changes but for transitory +changes if surprisingly on a given day + + align:start position:0% +changes if surprisingly on a given day + + + align:start position:0% +changes if surprisingly on a given day +people get + + align:start position:0% +people get + + + align:start position:0% +people get +more money then + + align:start position:0% +more money then + + + align:start position:0% +more money then +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +drivers work few hours and that's very + + align:start position:0% +drivers work few hours and that's very + + + align:start position:0% +drivers work few hours and that's very +hard to explain for the neoclassical + + align:start position:0% +hard to explain for the neoclassical + + + align:start position:0% +hard to explain for the neoclassical +model + + align:start position:0% +model + + + align:start position:0% +model +because essentially like you shouldn't + + align:start position:0% +because essentially like you shouldn't + + + align:start position:0% +because essentially like you shouldn't +care about like whether you make the + + align:start position:0% +care about like whether you make the + + + align:start position:0% +care about like whether you make the +money on monday on tuesday as i said you + + align:start position:0% +money on monday on tuesday as i said you + + + align:start position:0% +money on monday on tuesday as i said you +should care about how much you money + + align:start position:0% +should care about how much you money + + + align:start position:0% +should care about how much you money +you make overall and how many hours you + + align:start position:0% +you make overall and how many hours you + + + align:start position:0% +you make overall and how many hours you +uh work + + align:start position:0% +uh work + + + align:start position:0% +uh work +and so it's very hard to explain this + + align:start position:0% +and so it's very hard to explain this + + + align:start position:0% +and so it's very hard to explain this +and sort of the explanation + + align:start position:0% +and sort of the explanation + + + align:start position:0% +and sort of the explanation +uh that cameradoll and others um + + align:start position:0% +uh that cameradoll and others um + + + align:start position:0% +uh that cameradoll and others um +we're testing or or arguing is + + align:start position:0% +we're testing or or arguing is + + + align:start position:0% +we're testing or or arguing is +essentially this has to do with um + + align:start position:0% +essentially this has to do with um + + + align:start position:0% +essentially this has to do with um +reference dependence and so what's being + + align:start position:0% +reference dependence and so what's being + + + align:start position:0% +reference dependence and so what's being +evaluated in a reference dependent way + + align:start position:0% +evaluated in a reference dependent way + + + align:start position:0% +evaluated in a reference dependent way +or how do we think about this + + align:start position:0% +or how do we think about this + + + align:start position:0% +or how do we think about this +yeah i have a question yeah um how did + + align:start position:0% +yeah i have a question yeah um how did + + + align:start position:0% +yeah i have a question yeah um how did +they + + align:start position:0% +they + + + align:start position:0% +they +rule out the possibility that like maybe + + align:start position:0% +rule out the possibility that like maybe + + + align:start position:0% +rule out the possibility that like maybe +there's like um + + align:start position:0% +there's like um + + + align:start position:0% +there's like um +reverse causality maybe i'll say where + + align:start position:0% +reverse causality maybe i'll say where + + + align:start position:0% +reverse causality maybe i'll say where +none of the cab drivers want to work + + align:start position:0% +none of the cab drivers want to work + + + align:start position:0% +none of the cab drivers want to work +that much because of supply and demand + + align:start position:0% +that much because of supply and demand + + + align:start position:0% +that much because of supply and demand +but they just go up + + align:start position:0% + + + + align:start position:0% + +so so that's to say like effort costs + + align:start position:0% +so so that's to say like effort costs + + + align:start position:0% +so so that's to say like effort costs +are high + + align:start position:0% +are high + + + align:start position:0% +are high +so usually it's to do with like other + + align:start position:0% +so usually it's to do with like other + + + align:start position:0% +so usually it's to do with like other +drivers so let me let me actually get + + align:start position:0% +drivers so let me let me actually get + + + align:start position:0% +drivers so let me let me actually get +the + + align:start position:0% +the + + + align:start position:0% +the +so let me defer this for one second i + + align:start position:0% +so let me defer this for one second i + + + align:start position:0% +so let me defer this for one second i +have like a slide on like confounds + + align:start position:0% +have like a slide on like confounds + + + align:start position:0% +have like a slide on like confounds +and then we can see whether it addresses + + align:start position:0% +and then we can see whether it addresses + + + align:start position:0% +and then we can see whether it addresses +your question and then get get back to + + align:start position:0% +your question and then get get back to + + + align:start position:0% +your question and then get get back to +that + + align:start position:0% +that + + + align:start position:0% +that +but that's a good question so + + align:start position:0% +but that's a good question so + + + align:start position:0% +but that's a good question so +uh what is being evaluated in reference + + align:start position:0% +uh what is being evaluated in reference + + + align:start position:0% +uh what is being evaluated in reference +dependent way here what are people + + align:start position:0% +dependent way here what are people + + + align:start position:0% +dependent way here what are people +looking at in terms of + + align:start position:0% +looking at in terms of + + + align:start position:0% +looking at in terms of +where is the reference point in the + + align:start position:0% +where is the reference point in the + + + align:start position:0% +where is the reference point in the +evaluation here + + align:start position:0% +evaluation here + + + align:start position:0% +evaluation here +yes um i guess if you're a cab driver + + align:start position:0% +yes um i guess if you're a cab driver + + + align:start position:0% +yes um i guess if you're a cab driver +you + + align:start position:0% +you + + + align:start position:0% +you +kind of say oh i want to make like this + + align:start position:0% +kind of say oh i want to make like this + + + align:start position:0% +kind of say oh i want to make like this +much money today and then you just kind + + align:start position:0% +much money today and then you just kind + + + align:start position:0% +much money today and then you just kind +of like work until + + align:start position:0% +of like work until + + + align:start position:0% +of like work until +you feel like you've made it up and then + + align:start position:0% +you feel like you've made it up and then + + + align:start position:0% +you feel like you've made it up and then +you just stop right + + align:start position:0% +you just stop right + + + align:start position:0% +you just stop right +exactly you have to pay your fixed fee + + align:start position:0% +exactly you have to pay your fixed fee + + + align:start position:0% +exactly you have to pay your fixed fee +for the day or for the month or whatever + + align:start position:0% +for the day or for the month or whatever + + + align:start position:0% +for the day or for the month or whatever +but like there's an implicit uh + + align:start position:0% +but like there's an implicit uh + + + align:start position:0% +but like there's an implicit uh +fixed fee for the day so you kind of + + align:start position:0% +fixed fee for the day so you kind of + + + align:start position:0% +fixed fee for the day so you kind of +want to make at least that much money to + + align:start position:0% +want to make at least that much money to + + + align:start position:0% +want to make at least that much money to +make not a loss you probably have some + + align:start position:0% +make not a loss you probably have some + + + align:start position:0% +make not a loss you probably have some +positive target in some way and saying + + align:start position:0% +positive target in some way and saying + + + align:start position:0% +positive target in some way and saying +like i want to make uh + + align:start position:0% +like i want to make uh + + + align:start position:0% +like i want to make uh +pay back like my um my fee plus you want + + align:start position:0% +pay back like my um my fee plus you want + + + align:start position:0% +pay back like my um my fee plus you want +to make some money for the day + + align:start position:0% +to make some money for the day + + + align:start position:0% +to make some money for the day +and minus sort of expenses and once you + + align:start position:0% +and minus sort of expenses and once you + + + align:start position:0% +and minus sort of expenses and once you +reach that target + + align:start position:0% +reach that target + + + align:start position:0% +reach that target +you are in the gain domain below that + + align:start position:0% +you are in the gain domain below that + + + align:start position:0% +you are in the gain domain below that +you are in the last domain + + align:start position:0% +you are in the last domain + + + align:start position:0% +you are in the last domain +right and so the daily income + + align:start position:0% +right and so the daily income + + + align:start position:0% +right and so the daily income +essentially and that's essentially sort + + align:start position:0% +essentially and that's essentially sort + + + align:start position:0% +essentially and that's essentially sort +of like + + align:start position:0% +of like + + + align:start position:0% +of like +uh money after paying back the fee but + + align:start position:0% +uh money after paying back the fee but + + + align:start position:0% +uh money after paying back the fee but +you could also get uh it's essentially + + align:start position:0% +you could also get uh it's essentially + + + align:start position:0% +you could also get uh it's essentially +your + + align:start position:0% +your + + + align:start position:0% +your +uh uh what's being evaluated in the + + align:start position:0% +uh uh what's being evaluated in the + + + align:start position:0% +uh uh what's being evaluated in the +reference append network + + align:start position:0% +reference append network + + + align:start position:0% +reference append network +what's the reference point it's some + + align:start position:0% +what's the reference point it's some + + + align:start position:0% +what's the reference point it's some +daily target that you have often it's + + align:start position:0% +daily target that you have often it's + + + align:start position:0% +daily target that you have often it's +like expectation + + align:start position:0% +like expectation + + + align:start position:0% +like expectation +and so on and sort of essentially how + + align:start position:0% +and so on and sort of essentially how + + + align:start position:0% +and so on and sort of essentially how +much you think + + align:start position:0% +much you think + + + align:start position:0% +much you think +you will make and then what's the + + align:start position:0% +you will make and then what's the + + + align:start position:0% +you will make and then what's the +feature of the value of a function that + + align:start position:0% +feature of the value of a function that + + + align:start position:0% +feature of the value of a function that +explains the phenomena well it's loss of + + align:start position:0% +explains the phenomena well it's loss of + + + align:start position:0% +explains the phenomena well it's loss of +version if you're like falling short of + + align:start position:0% +version if you're like falling short of + + + align:start position:0% +version if you're like falling short of +the target + + align:start position:0% +the target + + + align:start position:0% +the target +essentially your marginal utility how + + align:start position:0% +essentially your marginal utility how + + + align:start position:0% +essentially your marginal utility how +much when you drive another hour or + + align:start position:0% +much when you drive another hour or + + + align:start position:0% +much when you drive another hour or +another trip + + align:start position:0% +another trip + + + align:start position:0% +another trip +the marginal utility that you get to see + + align:start position:0% +the marginal utility that you get to see + + + align:start position:0% +the marginal utility that you get to see +it then the value function is very steep + + align:start position:0% +it then the value function is very steep + + + align:start position:0% +it then the value function is very steep +below the target + + align:start position:0% +below the target + + + align:start position:0% +below the target +is very high once you reach the target + + align:start position:0% +is very high once you reach the target + + + align:start position:0% +is very high once you reach the target +it's very flat and then essentially you + + align:start position:0% +it's very flat and then essentially you + + + align:start position:0% +it's very flat and then essentially you +you you tend to stop does that make + + align:start position:0% +you you tend to stop does that make + + + align:start position:0% +you you tend to stop does that make +sense yeah + + align:start position:0% +sense yeah + + + align:start position:0% +sense yeah +okay great so um the main takeaway here + + align:start position:0% +okay great so um the main takeaway here + + + align:start position:0% +okay great so um the main takeaway here +is although if drivers often stop at + + align:start position:0% +is although if drivers often stop at + + + align:start position:0% +is although if drivers often stop at +their daily income target + + align:start position:0% +their daily income target + + + align:start position:0% +their daily income target +um drivers with a higher wage reach + + align:start position:0% +um drivers with a higher wage reach + + + align:start position:0% +um drivers with a higher wage reach +their targets faster and they work few + + align:start position:0% +their targets faster and they work few + + + align:start position:0% +their targets faster and they work few +hours + + align:start position:0% +hours + + + align:start position:0% +hours +again that's like variation uh uh uh + + align:start position:0% +again that's like variation uh uh uh + + + align:start position:0% +again that's like variation uh uh uh +within + + align:start position:0% +within + + + align:start position:0% +within +drivers um across days and so that + + align:start position:0% +drivers um across days and so that + + + align:start position:0% +drivers um across days and so that +there's lots of + + align:start position:0% +there's lots of + + + align:start position:0% +there's lots of +subsequent work and debate regarding + + align:start position:0% +subsequent work and debate regarding + + + align:start position:0% +subsequent work and debate regarding +this finding that the debate is still + + align:start position:0% +this finding that the debate is still + + + align:start position:0% +this finding that the debate is still +ongoing + + align:start position:0% +ongoing + + + align:start position:0% +ongoing +for example one reason paper looks at + + align:start position:0% +for example one reason paper looks at + + + align:start position:0% +for example one reason paper looks at +like tips that people + + align:start position:0% +like tips that people + + + align:start position:0% +like tips that people +uh drivers get unexpectedly so sometimes + + align:start position:0% +uh drivers get unexpectedly so sometimes + + + align:start position:0% +uh drivers get unexpectedly so sometimes +drivers get like large tips sometimes + + align:start position:0% +drivers get like large tips sometimes + + + align:start position:0% +drivers get like large tips sometimes +get small + + align:start position:0% +get small + + + align:start position:0% +get small +tips it depends a lot like when in the + + align:start position:0% +tips it depends a lot like when in the + + + align:start position:0% +tips it depends a lot like when in the +day they receive the tip if they receive + + align:start position:0% +day they receive the tip if they receive + + + align:start position:0% +day they receive the tip if they receive +it really early versus late if they sort + + align:start position:0% +it really early versus late if they sort + + + align:start position:0% +it really early versus late if they sort +of get to their target + + align:start position:0% +of get to their target + + + align:start position:0% +of get to their target +and essentially the target seems to be + + align:start position:0% +and essentially the target seems to be + + + align:start position:0% +and essentially the target seems to be +adjusting over time uh but overall this + + align:start position:0% +adjusting over time uh but overall this + + + align:start position:0% +adjusting over time uh but overall this +is sort of getting a little bit at your + + align:start position:0% +is sort of getting a little bit at your + + + align:start position:0% +is sort of getting a little bit at your +question um + + align:start position:0% +question um + + + align:start position:0% +question um +uh where we think it's not sort of + + align:start position:0% +uh where we think it's not sort of + + + align:start position:0% +uh where we think it's not sort of +aggregate um + + align:start position:0% +aggregate um + + + align:start position:0% +aggregate um +supply but the debate is over are still + + align:start position:0% +supply but the debate is over are still + + + align:start position:0% +supply but the debate is over are still +ongoing but overall we sort of think + + align:start position:0% +ongoing but overall we sort of think + + + align:start position:0% +ongoing but overall we sort of think +that + + align:start position:0% +that + + + align:start position:0% +that +lots of labor supply decisions when + + align:start position:0% +lots of labor supply decisions when + + + align:start position:0% +lots of labor supply decisions when +people have daily decisions of how many + + align:start position:0% +people have daily decisions of how many + + + align:start position:0% +people have daily decisions of how many +hours to work and their + + align:start position:0% +hours to work and their + + + align:start position:0% +hours to work and their +wages vary depend on uh reference points + + align:start position:0% +wages vary depend on uh reference points + + + align:start position:0% +wages vary depend on uh reference points +uh and might sort of potentially be at + + align:start position:0% +uh and might sort of potentially be at + + + align:start position:0% +uh and might sort of potentially be at +least um suboptimal or put differently + + align:start position:0% +least um suboptimal or put differently + + + align:start position:0% +least um suboptimal or put differently +they could people would could work few + + align:start position:0% +they could people would could work few + + + align:start position:0% +they could people would could work few +hours + + align:start position:0% +hours + + + align:start position:0% +hours +um and trying to sort of adjust their + + align:start position:0% +um and trying to sort of adjust their + + + align:start position:0% +um and trying to sort of adjust their +overall amounts you can actually when + + align:start position:0% +overall amounts you can actually when + + + align:start position:0% +overall amounts you can actually when +for a while like this you can ask your + + align:start position:0% +for a while like this you can ask your + + + align:start position:0% +for a while like this you can ask your +uber lyft drivers what they're doing + + align:start position:0% +uber lyft drivers what they're doing + + + align:start position:0% +uber lyft drivers what they're doing +and so on and see whether they're a + + align:start position:0% +and so on and see whether they're a + + + align:start position:0% +and so on and see whether they're a +reference dependent uh a + + align:start position:0% +reference dependent uh a + + + align:start position:0% +reference dependent uh a +driver so they have reference dependent + + align:start position:0% +driver so they have reference dependent + + + align:start position:0% +driver so they have reference dependent +preferences now what are sort of + + align:start position:0% +preferences now what are sort of + + + align:start position:0% +preferences now what are sort of +potential alternative hypotheses one + + align:start position:0% +potential alternative hypotheses one + + + align:start position:0% +potential alternative hypotheses one +question one issue could be like + + align:start position:0% +question one issue could be like + + + align:start position:0% +question one issue could be like +liquidity constraints + + align:start position:0% +liquidity constraints + + + align:start position:0% +liquidity constraints +this is like for example if you just + + align:start position:0% +this is like for example if you just + + + align:start position:0% +this is like for example if you just +don't have enough cash and you have to + + align:start position:0% +don't have enough cash and you have to + + + align:start position:0% +don't have enough cash and you have to +pay back + + align:start position:0% +pay back + + + align:start position:0% +pay back +for uh your fee for the day or for the + + align:start position:0% +for uh your fee for the day or for the + + + align:start position:0% +for uh your fee for the day or for the +next day you might want to not work only + + align:start position:0% +next day you might want to not work only + + + align:start position:0% +next day you might want to not work only +very few hours on a given day + + align:start position:0% +very few hours on a given day + + + align:start position:0% +very few hours on a given day +uh it turns out that drivers who own + + align:start position:0% +uh it turns out that drivers who own + + + align:start position:0% +uh it turns out that drivers who own +their own medallion exhibit the same + + align:start position:0% +their own medallion exhibit the same + + + align:start position:0% +their own medallion exhibit the same +patterns + + align:start position:0% +patterns + + + align:start position:0% +patterns +they could be things like fatigue it's + + align:start position:0% +they could be things like fatigue it's + + + align:start position:0% +they could be things like fatigue it's +let's just say it's really tedious to + + align:start position:0% +let's just say it's really tedious to + + + align:start position:0% +let's just say it's really tedious to +work on certain days + + align:start position:0% +work on certain days + + + align:start position:0% +work on certain days +when wages are high we don't think + + align:start position:0% +when wages are high we don't think + + + align:start position:0% +when wages are high we don't think +that's going on in part because drivers + + align:start position:0% +that's going on in part because drivers + + + align:start position:0% +that's going on in part because drivers +themselves + + align:start position:0% +themselves + + + align:start position:0% +themselves +they say it's actually easier to drive + + align:start position:0% +they say it's actually easier to drive + + + align:start position:0% +they say it's actually easier to drive +with more passengers + + align:start position:0% +with more passengers + + + align:start position:0% +with more passengers +again recent papers in fact can also + + align:start position:0% +again recent papers in fact can also + + + align:start position:0% +again recent papers in fact can also +control for this and so on so we don't + + align:start position:0% +control for this and so on so we don't + + + align:start position:0% +control for this and so on so we don't +think it's actually + + align:start position:0% +think it's actually + + + align:start position:0% +think it's actually +um fatigue and this is i think what + + align:start position:0% +um fatigue and this is i think what + + + align:start position:0% +um fatigue and this is i think what +you're saying uh the last one is + + align:start position:0% +you're saying uh the last one is + + + align:start position:0% +you're saying uh the last one is +unobserved shocks so some shocks that + + align:start position:0% +unobserved shocks so some shocks that + + + align:start position:0% +unobserved shocks so some shocks that +affect all drivers labor supply at the + + align:start position:0% +affect all drivers labor supply at the + + + align:start position:0% +affect all drivers labor supply at the +same time + + align:start position:0% +same time + + + align:start position:0% +same time +example you know there are some days in + + align:start position:0% +example you know there are some days in + + + align:start position:0% +example you know there are some days in +which all drivers get the flu + + align:start position:0% +which all drivers get the flu + + + align:start position:0% +which all drivers get the flu +uh fewer drivers will work and those who + + align:start position:0% +uh fewer drivers will work and those who + + + align:start position:0% +uh fewer drivers will work and those who +will work uh + + align:start position:0% +will work uh + + + align:start position:0% +will work uh +work few hours and those who work get + + align:start position:0% +work few hours and those who work get + + + align:start position:0% +work few hours and those who work get +uh get higher wages + + align:start position:0% +uh get higher wages + + + align:start position:0% +uh get higher wages +we that's a little bit trickier for them + + align:start position:0% +we that's a little bit trickier for them + + + align:start position:0% +we that's a little bit trickier for them +to to + + align:start position:0% +to to + + + align:start position:0% +to to +to to roll out in part there's other + + align:start position:0% +to to roll out in part there's other + + + align:start position:0% +to to roll out in part there's other +papers other studies afterwards that + + align:start position:0% +papers other studies afterwards that + + + align:start position:0% +papers other studies afterwards that +sort of try to + + align:start position:0% +sort of try to + + + align:start position:0% +sort of try to +get at this usually um um + + align:start position:0% +get at this usually um um + + + align:start position:0% +get at this usually um um +yeah for this specific data that's hard + + align:start position:0% +yeah for this specific data that's hard + + + align:start position:0% +yeah for this specific data that's hard +to do i think for the other + + align:start position:0% +to do i think for the other + + + align:start position:0% +to do i think for the other +data where people have essentially not + + align:start position:0% +data where people have essentially not + + + align:start position:0% +data where people have essentially not +just + + align:start position:0% +just + + + align:start position:0% +just +daily so this is essentially trip sheets + + align:start position:0% +daily so this is essentially trip sheets + + + align:start position:0% +daily so this is essentially trip sheets +so they have what they're using mostly + + align:start position:0% +so they have what they're using mostly + + + align:start position:0% +so they have what they're using mostly +is like daily wages overall + + align:start position:0% +is like daily wages overall + + + align:start position:0% +is like daily wages overall +they don't even have the wage they only + + align:start position:0% +they don't even have the wage they only + + + align:start position:0% +they don't even have the wage they only +have the um + + align:start position:0% +have the um + + + align:start position:0% +have the um +the overall um uh earnings and then the + + align:start position:0% +the overall um uh earnings and then the + + + align:start position:0% +the overall um uh earnings and then the +hours and then they sort of impute the + + align:start position:0% +hours and then they sort of impute the + + + align:start position:0% +hours and then they sort of impute the +wage dividing the two which causes some + + align:start position:0% +wage dividing the two which causes some + + + align:start position:0% +wage dividing the two which causes some +other trouble + + align:start position:0% +other trouble + + + align:start position:0% +other trouble +but once you have like uber data once + + align:start position:0% +but once you have like uber data once + + + align:start position:0% +but once you have like uber data once +you have like specific trips in + + align:start position:0% +you have like specific trips in + + + align:start position:0% +you have like specific trips in +particular also tips and so on + + align:start position:0% +particular also tips and so on + + + align:start position:0% +particular also tips and so on +you can look at on a given day uh when i + + align:start position:0% +you can look at on a given day uh when i + + + align:start position:0% +you can look at on a given day uh when i +get + + align:start position:0% +get + + + align:start position:0% +get +like a high tip versus a low tip uh uh + + align:start position:0% +like a high tip versus a low tip uh uh + + + align:start position:0% +like a high tip versus a low tip uh uh +how do + + align:start position:0% +how do + + + align:start position:0% +how do +you can you can look at like you can + + align:start position:0% +you can you can look at like you can + + + align:start position:0% +you can you can look at like you can +predict essentially how much i'm gonna + + align:start position:0% +predict essentially how much i'm gonna + + + align:start position:0% +predict essentially how much i'm gonna +earn on a given day + + align:start position:0% +earn on a given day + + + align:start position:0% +earn on a given day +so suppose you you predict that i'm + + align:start position:0% +so suppose you you predict that i'm + + + align:start position:0% +so suppose you you predict that i'm +gonna uh earn hundred dollars in a given + + align:start position:0% +gonna uh earn hundred dollars in a given + + + align:start position:0% +gonna uh earn hundred dollars in a given +day + + align:start position:0% +day + + + align:start position:0% +day +now i have like say fifty sixty dollars + + align:start position:0% +now i have like say fifty sixty dollars + + + align:start position:0% +now i have like say fifty sixty dollars +now i get like a large trip and like a + + align:start position:0% +now i get like a large trip and like a + + + align:start position:0% +now i get like a large trip and like a +tip and so on that gets me over that + + align:start position:0% +tip and so on that gets me over that + + + align:start position:0% +tip and so on that gets me over that +threshold you can look at where their + + align:start position:0% +threshold you can look at where their + + + align:start position:0% +threshold you can look at where their +stop + + align:start position:0% +stop + + + align:start position:0% +stop +you can look at the exact same thing + + align:start position:0% +you can look at the exact same thing + + + align:start position:0% +you can look at the exact same thing +when i have like only twenty dollars and + + align:start position:0% +when i have like only twenty dollars and + + + align:start position:0% +when i have like only twenty dollars and +they get a large ship to a stop and so + + align:start position:0% +they get a large ship to a stop and so + + + align:start position:0% +they get a large ship to a stop and so +on so you can essentially control for + + align:start position:0% +on so you can essentially control for + + + align:start position:0% +on so you can essentially control for +all of that + + align:start position:0% +all of that + + + align:start position:0% +all of that +and then do within a driver comparisons + + align:start position:0% +and then do within a driver comparisons + + + align:start position:0% +and then do within a driver comparisons +like for trips + + align:start position:0% +like for trips + + + align:start position:0% +like for trips +uh that happen to be large or small that + + align:start position:0% +uh that happen to be large or small that + + + align:start position:0% +uh that happen to be large or small that +you happen to get in a given hour and + + align:start position:0% +you happen to get in a given hour and + + + align:start position:0% +you happen to get in a given hour and +then you can sort of deal with like + + align:start position:0% +then you can sort of deal with like + + + align:start position:0% +then you can sort of deal with like +overall market conditions + + align:start position:0% +overall market conditions + + + align:start position:0% +overall market conditions +i think even better in the future there + + align:start position:0% +i think even better in the future there + + + align:start position:0% +i think even better in the future there +will be sort of like experiments and so + + align:start position:0% +will be sort of like experiments and so + + + align:start position:0% +will be sort of like experiments and so +on where you can look at + + align:start position:0% +on where you can look at + + + align:start position:0% +on where you can look at +when uber and lyft try to incentivize + + align:start position:0% +when uber and lyft try to incentivize + + + align:start position:0% +when uber and lyft try to incentivize +their workers and so just say + + align:start position:0% +their workers and so just say + + + align:start position:0% +their workers and so just say +essentially + + align:start position:0% +essentially + + + align:start position:0% +essentially +sometimes pay people more and unless + + align:start position:0% +sometimes pay people more and unless + + + align:start position:0% +sometimes pay people more and unless +randomly sort of explicitly randomly + + align:start position:0% +randomly sort of explicitly randomly + + + align:start position:0% +randomly sort of explicitly randomly +because they want to kind of learn about + + align:start position:0% +because they want to kind of learn about + + + align:start position:0% +because they want to kind of learn about +how to best incentivize the drivers and + + align:start position:0% +how to best incentivize the drivers and + + + align:start position:0% +how to best incentivize the drivers and +then you can control for everything + + align:start position:0% +then you can control for everything + + + align:start position:0% +then you can control for everything +because it's like explicitly random + + align:start position:0% +because it's like explicitly random + + + align:start position:0% +because it's like explicitly random +whether a certain driver gets like + + align:start position:0% +whether a certain driver gets like + + + align:start position:0% +whether a certain driver gets like +high versus low uh uh wages or sort of + + align:start position:0% +high versus low uh uh wages or sort of + + + align:start position:0% +high versus low uh uh wages or sort of +trip fares yeah okay + + align:start position:0% +trip fares yeah okay + + + align:start position:0% +trip fares yeah okay +um are any questions on the um + + align:start position:0% +um are any questions on the um + + + align:start position:0% +um are any questions on the um +on the uh labor supply + + align:start position:0% + + + + align:start position:0% + +yes um i'm a bit confused about the + + align:start position:0% +yes um i'm a bit confused about the + + + align:start position:0% +yes um i'm a bit confused about the +unobserved shocks + + align:start position:0% +unobserved shocks + + + align:start position:0% +unobserved shocks +because like if you get like a really + + align:start position:0% +because like if you get like a really + + + align:start position:0% +because like if you get like a really +large tip that doesn't necessarily like + + align:start position:0% +large tip that doesn't necessarily like + + + align:start position:0% +large tip that doesn't necessarily like +predict that the rest of the day you + + align:start position:0% +predict that the rest of the day you + + + align:start position:0% +predict that the rest of the day you +have higher wages if you kept working + + align:start position:0% +have higher wages if you kept working + + + align:start position:0% +have higher wages if you kept working +okay like you just get this really high + + align:start position:0% +okay like you just get this really high + + + align:start position:0% +okay like you just get this really high +tip and then you might be like oh + + align:start position:0% +tip and then you might be like oh + + + align:start position:0% +tip and then you might be like oh +today's a lucky day i can stop early + + align:start position:0% +today's a lucky day i can stop early + + + align:start position:0% +today's a lucky day i can stop early +but if i had worked more this day i + + align:start position:0% +but if i had worked more this day i + + + align:start position:0% +but if i had worked more this day i +wouldn't necessarily be making + + align:start position:0% +wouldn't necessarily be making + + + align:start position:0% +wouldn't necessarily be making +continuously more + + align:start position:0% +continuously more + + + align:start position:0% +continuously more +than normal right so in the unobserved + + align:start position:0% +than normal right so in the unobserved + + + align:start position:0% +than normal right so in the unobserved +in the large tip + + align:start position:0% +in the large tip + + + align:start position:0% +in the large tip +example the assumption is exactly or + + align:start position:0% +example the assumption is exactly or + + + align:start position:0% +example the assumption is exactly or +what they show in the paper this is + + align:start position:0% +what they show in the paper this is + + + align:start position:0% +what they show in the paper this is +subsequent work not this specific work + + align:start position:0% +subsequent work not this specific work + + + align:start position:0% +subsequent work not this specific work +what they exactly show in this type of + + align:start position:0% +what they exactly show in this type of + + + align:start position:0% +what they exactly show in this type of +paper these are sort of random events in + + align:start position:0% +paper these are sort of random events in + + + align:start position:0% +paper these are sort of random events in +a sense it's + + align:start position:0% +a sense it's + + + align:start position:0% +a sense it's +really precisely not predictive of your + + align:start position:0% +really precisely not predictive of your + + + align:start position:0% +really precisely not predictive of your +future uh + + align:start position:0% +future uh + + + align:start position:0% +future uh +uh earnings it's random now one + + align:start position:0% +uh earnings it's random now one + + + align:start position:0% +uh earnings it's random now one +interpretation that you have is to say + + align:start position:0% +interpretation that you have is to say + + + align:start position:0% +interpretation that you have is to say +well it could be that you kind of have + + align:start position:0% +well it could be that you kind of have + + + align:start position:0% +well it could be that you kind of have +some expectations about your future + + align:start position:0% +some expectations about your future + + + align:start position:0% +some expectations about your future +earnings + + align:start position:0% +earnings + + + align:start position:0% +earnings +that could be particularly high or low + + align:start position:0% +that could be particularly high or low + + + align:start position:0% +that could be particularly high or low +it's like i got my lucky day + + align:start position:0% +it's like i got my lucky day + + + align:start position:0% +it's like i got my lucky day +and so on and so forth that is hard to + + align:start position:0% +and so on and so forth that is hard to + + + align:start position:0% +and so on and so forth that is hard to +rule out and sometimes if you had + + align:start position:0% +rule out and sometimes if you had + + + align:start position:0% +rule out and sometimes if you had +rational expectations uh that's hard to + + align:start position:0% +rational expectations uh that's hard to + + + align:start position:0% +rational expectations uh that's hard to +explain for the neoclassical model + + align:start position:0% +explain for the neoclassical model + + + align:start position:0% +explain for the neoclassical model +what's harder to rule out is to say + + align:start position:0% +what's harder to rule out is to say + + + align:start position:0% +what's harder to rule out is to say +you know i now think like i got my lucky + + align:start position:0% +you know i now think like i got my lucky + + + align:start position:0% +you know i now think like i got my lucky +draw for the day and that's it and i'm + + align:start position:0% +draw for the day and that's it and i'm + + + align:start position:0% +draw for the day and that's it and i'm +not gonna + + align:start position:0% +not gonna + + + align:start position:0% +not gonna +uh i get any lucky draw again let's just + + align:start position:0% +uh i get any lucky draw again let's just + + + align:start position:0% +uh i get any lucky draw again let's just +call it a day + + align:start position:0% +call it a day + + + align:start position:0% +call it a day +that is hard to rule out but what is um + + align:start position:0% +that is hard to rule out but what is um + + + align:start position:0% +that is hard to rule out but what is um +hard to explain for the neoclassical uh + + align:start position:0% +hard to explain for the neoclassical uh + + + align:start position:0% +hard to explain for the neoclassical uh +model i think we can sort of reject is + + align:start position:0% +model i think we can sort of reject is + + + align:start position:0% +model i think we can sort of reject is +to say + + align:start position:0% +to say + + + align:start position:0% +to say +if you just think this is a shock which + + align:start position:0% +if you just think this is a shock which + + + align:start position:0% +if you just think this is a shock which +really in reality it is and you just + + align:start position:0% +really in reality it is and you just + + + align:start position:0% +really in reality it is and you just +happen to get a bunch of money on given + + align:start position:0% +happen to get a bunch of money on given + + + align:start position:0% +happen to get a bunch of money on given +day + + align:start position:0% +day + + + align:start position:0% +day +uh just randomly uh that is + + align:start position:0% +uh just randomly uh that is + + + align:start position:0% +uh just randomly uh that is +then the reference dependent model can + + align:start position:0% +then the reference dependent model can + + + align:start position:0% +then the reference dependent model can +sort of explain why you stop early + + align:start position:0% +sort of explain why you stop early + + + align:start position:0% +sort of explain why you stop early +because you it just puts you + + align:start position:0% +because you it just puts you + + + align:start position:0% +because you it just puts you +tips gets you over the reference point + + align:start position:0% +tips gets you over the reference point + + + align:start position:0% +tips gets you over the reference point +the neoclassical model should just say + + align:start position:0% +the neoclassical model should just say + + + align:start position:0% +the neoclassical model should just say +depends on like essentially how many + + align:start position:0% +depends on like essentially how many + + + align:start position:0% +depends on like essentially how many +hours you want to work on a given day + + align:start position:0% +hours you want to work on a given day + + + align:start position:0% +hours you want to work on a given day +it's nothing to do with a target because + + align:start position:0% +it's nothing to do with a target because + + + align:start position:0% +it's nothing to do with a target because +essentially again it doesn't matter + + align:start position:0% +essentially again it doesn't matter + + + align:start position:0% +essentially again it doesn't matter +whether you make money on monday or + + align:start position:0% +whether you make money on monday or + + + align:start position:0% +whether you make money on monday or +tuesday or wednesday you should just + + align:start position:0% +tuesday or wednesday you should just + + + align:start position:0% +tuesday or wednesday you should just +care about like your overall amount of + + align:start position:0% +care about like your overall amount of + + + align:start position:0% +care about like your overall amount of +money that you make + + align:start position:0% +money that you make + + + align:start position:0% +money that you make +overall but that's a good question + + align:start position:0% +overall but that's a good question + + + align:start position:0% +overall but that's a good question +okay so now um a second paper is on the + + align:start position:0% +okay so now um a second paper is on the + + + align:start position:0% +okay so now um a second paper is on the +housing market + + align:start position:0% +housing market + + + align:start position:0% +housing market +so what is the natural reference point + + align:start position:0% +so what is the natural reference point + + + align:start position:0% +so what is the natural reference point +for housing + + align:start position:0% +for housing + + + align:start position:0% +for housing +markets or like how do we think about + + align:start position:0% +markets or like how do we think about + + + align:start position:0% +markets or like how do we think about +housing prices or how do you think about + + align:start position:0% +housing prices or how do you think about + + + align:start position:0% +housing prices or how do you think about +i guess + + align:start position:0% +i guess + + + align:start position:0% +i guess +a few of you will own a house but how + + align:start position:0% +a few of you will own a house but how + + + align:start position:0% +a few of you will own a house but how +would you think about if you if you + + align:start position:0% +would you think about if you if you + + + align:start position:0% +would you think about if you if you +owned a house + + align:start position:0% +owned a house + + + align:start position:0% +owned a house +how do you think about uh selling a + + align:start position:0% +how do you think about uh selling a + + + align:start position:0% +how do you think about uh selling a +house what is a natural reference point + + align:start position:0% +house what is a natural reference point + + + align:start position:0% +house what is a natural reference point +yes uh whatever it was for or like how + + align:start position:0% +yes uh whatever it was for or like how + + + align:start position:0% +yes uh whatever it was for or like how +it changes + + align:start position:0% +it changes + + + align:start position:0% +it changes +yeah so exactly so uh the previous + + align:start position:0% +yeah so exactly so uh the previous + + + align:start position:0% +yeah so exactly so uh the previous +purchase price it turns out it's a very + + align:start position:0% +purchase price it turns out it's a very + + + align:start position:0% +purchase price it turns out it's a very +very salient thing for owners people + + align:start position:0% +very salient thing for owners people + + + align:start position:0% +very salient thing for owners people +really know how much they paid for their + + align:start position:0% +really know how much they paid for their + + + align:start position:0% +really know how much they paid for their +house + + align:start position:0% +house + + + align:start position:0% +house +it's like a huge expense in their life + + align:start position:0% +it's like a huge expense in their life + + + align:start position:0% +it's like a huge expense in their life +they really remember it was like three + + align:start position:0% +they really remember it was like three + + + align:start position:0% +they really remember it was like three +hundred thousand five hundred thousand a + + align:start position:0% +hundred thousand five hundred thousand a + + + align:start position:0% +hundred thousand five hundred thousand a +million et cetera they know exactly how + + align:start position:0% +million et cetera they know exactly how + + + align:start position:0% +million et cetera they know exactly how +much they paid + + align:start position:0% +much they paid + + + align:start position:0% +much they paid +and that even asked people people know + + align:start position:0% +and that even asked people people know + + + align:start position:0% +and that even asked people people know +exactly how much they uh the majority of + + align:start position:0% +exactly how much they uh the majority of + + + align:start position:0% +exactly how much they uh the majority of +people know exactly how much they paid + + align:start position:0% +people know exactly how much they paid + + + align:start position:0% +people know exactly how much they paid +for their um home + + align:start position:0% +for their um home + + + align:start position:0% +for their um home +now one claim is that loss of version + + align:start position:0% +now one claim is that loss of version + + + align:start position:0% +now one claim is that loss of version +makes people unwilling to sell + + align:start position:0% +makes people unwilling to sell + + + align:start position:0% +makes people unwilling to sell +their houses at a loss and so what they + + align:start position:0% +their houses at a loss and so what they + + + align:start position:0% +their houses at a loss and so what they +would then do is they ask essentially + + align:start position:0% +would then do is they ask essentially + + + align:start position:0% +would then do is they ask essentially +for higher prices if a loss relative to + + align:start position:0% +for higher prices if a loss relative to + + + align:start position:0% +for higher prices if a loss relative to +like their their purchase price and + + align:start position:0% +like their their purchase price and + + + align:start position:0% +like their their purchase price and +let me just show you um exactly what i + + align:start position:0% +let me just show you um exactly what i + + + align:start position:0% +let me just show you um exactly what i +mean by that + + align:start position:0% +mean by that + + + align:start position:0% +mean by that +uh gina risa and meier have um boston + + align:start position:0% +uh gina risa and meier have um boston + + + align:start position:0% +uh gina risa and meier have um boston +condominium data from 1990 to 1997. + + align:start position:0% +condominium data from 1990 to 1997. + + + align:start position:0% +condominium data from 1990 to 1997. +um luckily for them there's lots of + + align:start position:0% +um luckily for them there's lots of + + + align:start position:0% +um luckily for them there's lots of +variation or fluctuations in the housing + + align:start position:0% +variation or fluctuations in the housing + + + align:start position:0% +variation or fluctuations in the housing +market during that time so the housing + + align:start position:0% +market during that time so the housing + + + align:start position:0% +market during that time so the housing +market went up a lot and then it went + + align:start position:0% +market went up a lot and then it went + + + align:start position:0% +market went up a lot and then it went +down a lot and went up a lot + + align:start position:0% +down a lot and went up a lot + + + align:start position:0% +down a lot and went up a lot +now suppose you have two sellers a and b + + align:start position:0% +now suppose you have two sellers a and b + + + align:start position:0% +now suppose you have two sellers a and b +who both want to sell their house or + + align:start position:0% +who both want to sell their house or + + + align:start position:0% +who both want to sell their house or +their home in 1994. + + align:start position:0% +their home in 1994. + + + align:start position:0% +their home in 1994. +now what we can do is we can look at + + align:start position:0% +now what we can do is we can look at + + + align:start position:0% +now what we can do is we can look at +these two people who suppose they have + + align:start position:0% +these two people who suppose they have + + + align:start position:0% +these two people who suppose they have +very similar houses + + align:start position:0% +very similar houses + + + align:start position:0% +very similar houses +based on observable characteristics and + + align:start position:0% +based on observable characteristics and + + + align:start position:0% +based on observable characteristics and +location and so on and so forth + + align:start position:0% +location and so on and so forth + + + align:start position:0% +location and so on and so forth +so once they have really comparable + + align:start position:0% +so once they have really comparable + + + align:start position:0% +so once they have really comparable +houses we can now look at + + align:start position:0% +houses we can now look at + + + align:start position:0% +houses we can now look at +people who seller a purchased their + + align:start position:0% +people who seller a purchased their + + + align:start position:0% +people who seller a purchased their +home really early on in 1989 that person + + align:start position:0% +home really early on in 1989 that person + + + align:start position:0% +home really early on in 1989 that person +happens to be quite unlucky because they + + align:start position:0% +happens to be quite unlucky because they + + + align:start position:0% +happens to be quite unlucky because they +just bought the house really at the peak + + align:start position:0% +just bought the house really at the peak + + + align:start position:0% +just bought the house really at the peak +of + + align:start position:0% +of + + + align:start position:0% +of +uh i guess the housing boom at the time + + align:start position:0% +uh i guess the housing boom at the time + + + align:start position:0% +uh i guess the housing boom at the time +or + + align:start position:0% +or + + + align:start position:0% +or +seller number b who purchased in 1991 uh + + align:start position:0% +seller number b who purchased in 1991 uh + + + align:start position:0% +seller number b who purchased in 1991 uh +uh that that person was relatively lucky + + align:start position:0% +uh that that person was relatively lucky + + + align:start position:0% +uh that that person was relatively lucky +the bot essentially had a price where + + align:start position:0% +the bot essentially had a price where + + + align:start position:0% +the bot essentially had a price where +at a time where the housing market was + + align:start position:0% +at a time where the housing market was + + + align:start position:0% +at a time where the housing market was +relatively low and uh + + align:start position:0% +relatively low and uh + + + align:start position:0% +relatively low and uh +appreciated quite a bit so now we can + + align:start position:0% +appreciated quite a bit so now we can + + + align:start position:0% +appreciated quite a bit so now we can +look at these two people + + align:start position:0% +look at these two people + + + align:start position:0% +look at these two people +and ask the question uh is seller a or + + align:start position:0% +and ask the question uh is seller a or + + + align:start position:0% +and ask the question uh is seller a or +seller b + + align:start position:0% +seller b + + + align:start position:0% +seller b +more likely to sell their house and and + + align:start position:0% +more likely to sell their house and and + + + align:start position:0% +more likely to sell their house and and +the hypothesis is that + + align:start position:0% +the hypothesis is that + + + align:start position:0% +the hypothesis is that +seller a will sort of view this as like + + align:start position:0% +seller a will sort of view this as like + + + align:start position:0% +seller a will sort of view this as like +a loss this seller will essentially just + + align:start position:0% +a loss this seller will essentially just + + + align:start position:0% +a loss this seller will essentially just +say i'm losing money here + + align:start position:0% +say i'm losing money here + + + align:start position:0% +say i'm losing money here +i don't want to sell and that seller + + align:start position:0% +i don't want to sell and that seller + + + align:start position:0% +i don't want to sell and that seller +might essentially ask for like a higher + + align:start position:0% +might essentially ask for like a higher + + + align:start position:0% +might essentially ask for like a higher +listing price and wants to like more + + align:start position:0% +listing price and wants to like more + + + align:start position:0% +listing price and wants to like more +money for this house because they don't + + align:start position:0% +money for this house because they don't + + + align:start position:0% +money for this house because they don't +want to make a + + align:start position:0% +want to make a + + + align:start position:0% +want to make a +a loss on that uh sale well seller b + + align:start position:0% +a loss on that uh sale well seller b + + + align:start position:0% +a loss on that uh sale well seller b +says i'm actually gaining money anyway + + align:start position:0% +says i'm actually gaining money anyway + + + align:start position:0% +says i'm actually gaining money anyway +so let's just sort of like uh + + align:start position:0% +so let's just sort of like uh + + + align:start position:0% +so let's just sort of like uh +post whatever you think is actually the + + align:start position:0% +post whatever you think is actually the + + + align:start position:0% +post whatever you think is actually the +expected market price might be happy to + + align:start position:0% +expected market price might be happy to + + + align:start position:0% +expected market price might be happy to +to sell at a lower price + + align:start position:0% +to sell at a lower price + + + align:start position:0% +to sell at a lower price +compared to seller a okay so one thing + + align:start position:0% +compared to seller a okay so one thing + + + align:start position:0% +compared to seller a okay so one thing +we can look at essentially are listing + + align:start position:0% +we can look at essentially are listing + + + align:start position:0% +we can look at essentially are listing +prices how much do people want for the + + align:start position:0% +prices how much do people want for the + + + align:start position:0% +prices how much do people want for the +houses + + align:start position:0% +houses + + + align:start position:0% +houses +effect second thing we can look at is + + align:start position:0% +effect second thing we can look at is + + + align:start position:0% +effect second thing we can look at is +like actual sales prices + + align:start position:0% +like actual sales prices + + + align:start position:0% +like actual sales prices +you know are you now like selling this + + align:start position:0% +you know are you now like selling this + + + align:start position:0% +you know are you now like selling this +at a higher lower price and number three + + align:start position:0% +at a higher lower price and number three + + + align:start position:0% +at a higher lower price and number three +we can look at like how long is the + + align:start position:0% +we can look at like how long is the + + + align:start position:0% +we can look at like how long is the +house on the market + + align:start position:0% +house on the market + + + align:start position:0% +house on the market +how long does it actually take to sell + + align:start position:0% +how long does it actually take to sell + + + align:start position:0% +how long does it actually take to sell +it that's a quite costly thing to do to + + align:start position:0% +it that's a quite costly thing to do to + + + align:start position:0% +it that's a quite costly thing to do to +have your house on the market for quite + + align:start position:0% +have your house on the market for quite + + + align:start position:0% +have your house on the market for quite +a while because essentially + + align:start position:0% +a while because essentially + + + align:start position:0% +a while because essentially +often people then don't already move + + align:start position:0% +often people then don't already move + + + align:start position:0% +often people then don't already move +somewhere else or they don't kind of + + align:start position:0% +somewhere else or they don't kind of + + + align:start position:0% +somewhere else or they don't kind of +live in the house because they have to + + align:start position:0% +live in the house because they have to + + + align:start position:0% +live in the house because they have to +sort of show it and make it available + + align:start position:0% +sort of show it and make it available + + + align:start position:0% +sort of show it and make it available +for + + align:start position:0% +for + + + align:start position:0% +for +showings and so on so it's a costly + + align:start position:0% +showings and so on so it's a costly + + + align:start position:0% +showings and so on so it's a costly +thing to do you really + + align:start position:0% +thing to do you really + + + align:start position:0% +thing to do you really +don't want to you have your house on the + + align:start position:0% +don't want to you have your house on the + + + align:start position:0% +don't want to you have your house on the +market for like several months + + align:start position:0% +market for like several months + + + align:start position:0% +market for like several months +but it's sort of the broad idea claire + + align:start position:0% +but it's sort of the broad idea claire + + + align:start position:0% +but it's sort of the broad idea claire +what we're trying to do + + align:start position:0% +what we're trying to do + + + align:start position:0% +what we're trying to do +okay so what predictions um + + align:start position:0% +okay so what predictions um + + + align:start position:0% +okay so what predictions um +do you want to test but you want to test + + align:start position:0% +do you want to test but you want to test + + + align:start position:0% +do you want to test but you want to test +whether house owners are reluctant to + + align:start position:0% +whether house owners are reluctant to + + + align:start position:0% +whether house owners are reluctant to +sell their house when the current market + + align:start position:0% +sell their house when the current market + + + align:start position:0% +sell their house when the current market +price is below + + align:start position:0% +price is below + + + align:start position:0% +price is below +the purchase price so the ideal + + align:start position:0% +the purchase price so the ideal + + + align:start position:0% +the purchase price so the ideal +specification is essentially the + + align:start position:0% +specification is essentially the + + + align:start position:0% +specification is essentially the +following we look at the list price on + + align:start position:0% +following we look at the list price on + + + align:start position:0% +following we look at the list price on +the left-hand side + + align:start position:0% +the left-hand side + + + align:start position:0% +the left-hand side +and then we are going to run a + + align:start position:0% +and then we are going to run a + + + align:start position:0% +and then we are going to run a +regression that looks at some constant + + align:start position:0% +regression that looks at some constant + + + align:start position:0% +regression that looks at some constant +that's just kind of like time trends et + + align:start position:0% +that's just kind of like time trends et + + + align:start position:0% +that's just kind of like time trends et +cetera + + align:start position:0% +cetera + + + align:start position:0% +cetera +plus a beta which is the coefficient of + + align:start position:0% +plus a beta which is the coefficient of + + + align:start position:0% +plus a beta which is the coefficient of +interest or one coefficient + + align:start position:0% +interest or one coefficient + + + align:start position:0% +interest or one coefficient +of interest is of the actual market + + align:start position:0% +of interest is of the actual market + + + align:start position:0% +of interest is of the actual market +price how much is the thing worth + + align:start position:0% +price how much is the thing worth + + + align:start position:0% +price how much is the thing worth +and then delta on the loss is like how + + align:start position:0% +and then delta on the loss is like how + + + align:start position:0% +and then delta on the loss is like how +much do you lose relative to your + + align:start position:0% +much do you lose relative to your + + + align:start position:0% +much do you lose relative to your +purchase price now if people were not + + align:start position:0% +purchase price now if people were not + + + align:start position:0% +purchase price now if people were not +reference dependent what should we find + + align:start position:0% +reference dependent what should we find + + + align:start position:0% +reference dependent what should we find +what would be the predictions + + align:start position:0% +what would be the predictions + + + align:start position:0% +what would be the predictions +like the neoclassical model what should + + align:start position:0% +like the neoclassical model what should + + + align:start position:0% +like the neoclassical model what should +we find here + + align:start position:0% + + + + align:start position:0% + +yes + + align:start position:0% +yes + + + align:start position:0% +yes +exactly delta should not matter it + + align:start position:0% +exactly delta should not matter it + + + align:start position:0% +exactly delta should not matter it +shouldn't matter how much you lost or + + align:start position:0% +shouldn't matter how much you lost or + + + align:start position:0% +shouldn't matter how much you lost or +gained in that house + + align:start position:0% +gained in that house + + + align:start position:0% +gained in that house +uh what should matter is like what is + + align:start position:0% +uh what should matter is like what is + + + align:start position:0% +uh what should matter is like what is +the actual market value you should + + align:start position:0% +the actual market value you should + + + align:start position:0% +the actual market value you should +essentially try to + + align:start position:0% +essentially try to + + + align:start position:0% +essentially try to +be willing to sell it or not beta could + + align:start position:0% +be willing to sell it or not beta could + + + align:start position:0% +be willing to sell it or not beta could +be + + align:start position:0% +be + + + align:start position:0% +be +you know it doesn't have to be one it + + align:start position:0% +you know it doesn't have to be one it + + + align:start position:0% +you know it doesn't have to be one it +could be like everybody + + align:start position:0% +could be like everybody + + + align:start position:0% +could be like everybody +pays above the actual market for some + + align:start position:0% +pays above the actual market for some + + + align:start position:0% +pays above the actual market for some +housing bubble or whatever beta could be + + align:start position:0% +housing bubble or whatever beta could be + + + align:start position:0% +housing bubble or whatever beta could be +like + + align:start position:0% +like + + + align:start position:0% +like +1.1 or whatever you might be uh that + + align:start position:0% +1.1 or whatever you might be uh that + + + align:start position:0% +1.1 or whatever you might be uh that +depends on essentially sort of aggregate + + align:start position:0% +depends on essentially sort of aggregate + + + align:start position:0% +depends on essentially sort of aggregate +conditions and so on + + align:start position:0% +conditions and so on + + + align:start position:0% +conditions and so on +but delta really should not matter when + + align:start position:0% +but delta really should not matter when + + + align:start position:0% +but delta really should not matter when +i'm trying to sell you a house you + + align:start position:0% +i'm trying to sell you a house you + + + align:start position:0% +i'm trying to sell you a house you +should ask like what's the + + align:start position:0% +should ask like what's the + + + align:start position:0% +should ask like what's the +actual market value and i should um + + align:start position:0% +actual market value and i should um + + + align:start position:0% +actual market value and i should um +essentially then based on that + + align:start position:0% +essentially then based on that + + + align:start position:0% +essentially then based on that +uh uh put it under market um on that + + align:start position:0% +uh uh put it under market um on that + + + align:start position:0% +uh uh put it under market um on that +listing price + + align:start position:0% +listing price + + + align:start position:0% +listing price +uh but what might be the case is that + + align:start position:0% +uh but what might be the case is that + + + align:start position:0% +uh but what might be the case is that +the loss actually um + + align:start position:0% +the loss actually um + + + align:start position:0% +the loss actually um +matters now one problem here is that the + + align:start position:0% +matters now one problem here is that the + + + align:start position:0% +matters now one problem here is that the +actual market value is not observable + + align:start position:0% +actual market value is not observable + + + align:start position:0% +actual market value is not observable +right so i don't actually know what the + + align:start position:0% +right so i don't actually know what the + + + align:start position:0% +right so i don't actually know what the +market value is because that's like + + align:start position:0% +market value is because that's like + + + align:start position:0% +market value is because that's like +endogenous that's part of like the + + align:start position:0% +endogenous that's part of like the + + + align:start position:0% +endogenous that's part of like the +transaction + + align:start position:0% +transaction + + + align:start position:0% +transaction +so what can i do instead or how do i do + + align:start position:0% +so what can i do instead or how do i do + + + align:start position:0% +so what can i do instead or how do i do +this + + align:start position:0% + + + + align:start position:0% + +yes by asking people like would you like + + align:start position:0% +yes by asking people like would you like + + + align:start position:0% +yes by asking people like would you like +would you take this trade + + align:start position:0% +would you take this trade + + + align:start position:0% +would you take this trade +what they say right so you can look at + + align:start position:0% +what they say right so you can look at + + + align:start position:0% +what they say right so you can look at +actually the market + + align:start position:0% +actually the market + + + align:start position:0% +actually the market +outcome overall you can look at like who + + align:start position:0% +outcome overall you can look at like who + + + align:start position:0% +outcome overall you can look at like who +buys it and what's the actual purchase + + align:start position:0% +buys it and what's the actual purchase + + + align:start position:0% +buys it and what's the actual purchase +price + + align:start position:0% +price + + + align:start position:0% +price +now that might also be endogenous to + + align:start position:0% +now that might also be endogenous to + + + align:start position:0% +now that might also be endogenous to +like the listing price right so if you + + align:start position:0% +like the listing price right so if you + + + align:start position:0% +like the listing price right so if you +think you know the people who are lost a + + align:start position:0% +think you know the people who are lost a + + + align:start position:0% +think you know the people who are lost a +verse are + + align:start position:0% +verse are + + + align:start position:0% +verse are +listing their houses too high relatively + + align:start position:0% +listing their houses too high relatively + + + align:start position:0% +listing their houses too high relatively +compared to what the market value + + align:start position:0% +compared to what the market value + + + align:start position:0% +compared to what the market value +actually is + + align:start position:0% +actually is + + + align:start position:0% +actually is +it might actually be sold at a higher + + align:start position:0% +it might actually be sold at a higher + + + align:start position:0% +it might actually be sold at a higher +price so that could + + align:start position:0% +price so that could + + + align:start position:0% +price so that could +that's hard to interpret it could just + + align:start position:0% +that's hard to interpret it could just + + + align:start position:0% +that's hard to interpret it could just +be that if you sell it at a high + + align:start position:0% +be that if you sell it at a high + + + align:start position:0% +be that if you sell it at a high +if you list it at a very high price and + + align:start position:0% +if you list it at a very high price and + + + align:start position:0% +if you list it at a very high price and +wait for a long time you also sell it at + + align:start position:0% +wait for a long time you also sell it at + + + align:start position:0% +wait for a long time you also sell it at +a higher price + + align:start position:0% +a higher price + + + align:start position:0% +a higher price +but doesn't mean that it's actually + + align:start position:0% +but doesn't mean that it's actually + + + align:start position:0% +but doesn't mean that it's actually +worth that much it just means that like + + align:start position:0% +worth that much it just means that like + + + align:start position:0% +worth that much it just means that like +you happen to find + + align:start position:0% +you happen to find + + + align:start position:0% +you happen to find +a buyer who happens to be willing to pay + + align:start position:0% +a buyer who happens to be willing to pay + + + align:start position:0% +a buyer who happens to be willing to pay +a lot and that's more likely when you + + align:start position:0% +a lot and that's more likely when you + + + align:start position:0% +a lot and that's more likely when you +wait for a long time + + align:start position:0% +wait for a long time + + + align:start position:0% +wait for a long time +which is not necessarily optimal because + + align:start position:0% +which is not necessarily optimal because + + + align:start position:0% +which is not necessarily optimal because +it's actually quite costly to do that + + align:start position:0% +it's actually quite costly to do that + + + align:start position:0% +it's actually quite costly to do that +but you're saying something else which + + align:start position:0% +but you're saying something else which + + + align:start position:0% +but you're saying something else which +is like asking them about what they + + align:start position:0% +is like asking them about what they + + + align:start position:0% +is like asking them about what they +think but what are the characteristics + + align:start position:0% +think but what are the characteristics + + + align:start position:0% +think but what are the characteristics +that we could look at or what data + + align:start position:0% +that we could look at or what data + + + align:start position:0% +that we could look at or what data +could we look at + + align:start position:0% + + + + align:start position:0% + +like if you had like zillow data or data + + align:start position:0% +like if you had like zillow data or data + + + align:start position:0% +like if you had like zillow data or data +on like essentially a bunch of these + + align:start position:0% +on like essentially a bunch of these + + + align:start position:0% +on like essentially a bunch of these +apps where you can look at houses + + align:start position:0% +apps where you can look at houses + + + align:start position:0% +apps where you can look at houses +what data could you get yes you'd look + + align:start position:0% +what data could you get yes you'd look + + + align:start position:0% +what data could you get yes you'd look +at like the houses like in the + + align:start position:0% +at like the houses like in the + + + align:start position:0% +at like the houses like in the +neighborhood like similar + + align:start position:0% +neighborhood like similar + + + align:start position:0% +neighborhood like similar +houses exactly what redfin and zillow et + + align:start position:0% +houses exactly what redfin and zillow et + + + align:start position:0% +houses exactly what redfin and zillow et +cetera do these days is essentially they + + align:start position:0% +cetera do these days is essentially they + + + align:start position:0% +cetera do these days is essentially they +have these algorithms that try to + + align:start position:0% +have these algorithms that try to + + + align:start position:0% +have these algorithms that try to +predict + + align:start position:0% +predict + + + align:start position:0% +predict +uh the actual market sales price and + + align:start position:0% +uh the actual market sales price and + + + align:start position:0% +uh the actual market sales price and +what they tend to do essentially is look + + align:start position:0% +what they tend to do essentially is look + + + align:start position:0% +what they tend to do essentially is look +at + + align:start position:0% +at + + + align:start position:0% +at +exactly as you say surrounding houses + + align:start position:0% +exactly as you say surrounding houses + + + align:start position:0% +exactly as you say surrounding houses +that are similar in some characteristics + + align:start position:0% +that are similar in some characteristics + + + align:start position:0% +that are similar in some characteristics +they look at the number of they look at + + align:start position:0% +they look at the number of they look at + + + align:start position:0% +they look at the number of they look at +the square footage they look at the + + align:start position:0% +the square footage they look at the + + + align:start position:0% +the square footage they look at the +number of uh + + align:start position:0% +number of uh + + + align:start position:0% +number of uh +bathrooms and rooms in general they look + + align:start position:0% +bathrooms and rooms in general they look + + + align:start position:0% +bathrooms and rooms in general they look +at like sort of like location and so on + + align:start position:0% +at like sort of like location and so on + + + align:start position:0% +at like sort of like location and so on +and so forth + + align:start position:0% +and so forth + + + align:start position:0% +and so forth +and then you can predict um uh + + align:start position:0% +and then you can predict um uh + + + align:start position:0% +and then you can predict um uh +how much uh and sort of they look at + + align:start position:0% +how much uh and sort of they look at + + + align:start position:0% +how much uh and sort of they look at +also time trends and so on + + align:start position:0% +also time trends and so on + + + align:start position:0% +also time trends and so on +how much is the actual market value but + + align:start position:0% +how much is the actual market value but + + + align:start position:0% +how much is the actual market value but +it's essentially fundamentally it's like + + align:start position:0% +it's essentially fundamentally it's like + + + align:start position:0% +it's essentially fundamentally it's like +a prediction exercise you can try to + + align:start position:0% +a prediction exercise you can try to + + + align:start position:0% +a prediction exercise you can try to +predict + + align:start position:0% +predict + + + align:start position:0% +predict +uh what the actual value is and that's + + align:start position:0% +uh what the actual value is and that's + + + align:start position:0% +uh what the actual value is and that's +exactly what uh genovese and meyer do + + align:start position:0% +exactly what uh genovese and meyer do + + + align:start position:0% +exactly what uh genovese and meyer do +they do + + align:start position:0% +they do + + + align:start position:0% +they do +some more fancy things that try to get + + align:start position:0% +some more fancy things that try to get + + + align:start position:0% +some more fancy things that try to get +at like other + + align:start position:0% +at like other + + + align:start position:0% +at like other +unobservable characteristics and so on + + align:start position:0% +unobservable characteristics and so on + + + align:start position:0% +unobservable characteristics and so on +but the essence of this is exactly a + + align:start position:0% +but the essence of this is exactly a + + + align:start position:0% +but the essence of this is exactly a +prediction exercise where they say + + align:start position:0% +prediction exercise where they say + + + align:start position:0% +prediction exercise where they say +let's just look at uh the + + align:start position:0% +let's just look at uh the + + + align:start position:0% +let's just look at uh the +characteristics of this house let's try + + align:start position:0% +characteristics of this house let's try + + + align:start position:0% +characteristics of this house let's try +to predict what the market value is + + align:start position:0% +to predict what the market value is + + + align:start position:0% +to predict what the market value is +and then look at the loss which is + + align:start position:0% +and then look at the loss which is + + + align:start position:0% +and then look at the loss which is +essentially the difference between the + + align:start position:0% +essentially the difference between the + + + align:start position:0% +essentially the difference between the +previous selling price and the expected + + align:start position:0% +previous selling price and the expected + + + align:start position:0% +previous selling price and the expected +selling + + align:start position:0% +selling + + + align:start position:0% +selling +price truncated from zero because + + align:start position:0% +price truncated from zero because + + + align:start position:0% +price truncated from zero because +otherwise it's a gain + + align:start position:0% +otherwise it's a gain + + + align:start position:0% +otherwise it's a gain +and then we can look at uh does it + + align:start position:0% +and then we can look at uh does it + + + align:start position:0% +and then we can look at uh does it +really seem that like when people are in + + align:start position:0% +really seem that like when people are in + + + align:start position:0% +really seem that like when people are in +the lost domain when their losses + + align:start position:0% +the lost domain when their losses + + + align:start position:0% +the lost domain when their losses +positive + + align:start position:0% +positive + + + align:start position:0% +positive +are they now um selling their house or + + align:start position:0% +are they now um selling their house or + + + align:start position:0% +are they now um selling their house or +trying to sell their house + + align:start position:0% +trying to sell their house + + + align:start position:0% +trying to sell their house +at a higher um price yes + + align:start position:0% +at a higher um price yes + + + align:start position:0% +at a higher um price yes +how would you account for something like + + align:start position:0% +how would you account for something like + + + align:start position:0% +how would you account for something like +recent renovations like since the last + + align:start position:0% +recent renovations like since the last + + + align:start position:0% +recent renovations like since the last +listing and + + align:start position:0% +listing and + + + align:start position:0% +listing and +relative to any other similar units or + + align:start position:0% +relative to any other similar units or + + + align:start position:0% +relative to any other similar units or +causes + + align:start position:0% +causes + + + align:start position:0% +causes +and nearby right + + align:start position:0% +and nearby right + + + align:start position:0% +and nearby right +so um that's tricky to do and i don't + + align:start position:0% +so um that's tricky to do and i don't + + + align:start position:0% +so um that's tricky to do and i don't +think they have this in their data so + + align:start position:0% +think they have this in their data so + + + align:start position:0% +think they have this in their data so +what you'd have to assume here and + + align:start position:0% +what you'd have to assume here and + + + align:start position:0% +what you'd have to assume here and +that's + + align:start position:0% +that's + + + align:start position:0% +that's +perhaps reasonable is to say that when + + align:start position:0% +perhaps reasonable is to say that when + + + align:start position:0% +perhaps reasonable is to say that when +you look at sort of this picture + + align:start position:0% +you look at sort of this picture + + + align:start position:0% +you look at sort of this picture +that um seller a and zellerb did not do + + align:start position:0% +that um seller a and zellerb did not do + + + align:start position:0% +that um seller a and zellerb did not do +differential renovation depending on + + align:start position:0% +differential renovation depending on + + + align:start position:0% +differential renovation depending on +when they bought the house right so if + + align:start position:0% +when they bought the house right so if + + + align:start position:0% +when they bought the house right so if +you said + + align:start position:0% +you said + + + align:start position:0% +you said +it's fine if people have done + + align:start position:0% +it's fine if people have done + + + align:start position:0% +it's fine if people have done +renovations for example this is what i + + align:start position:0% +renovations for example this is what i + + + align:start position:0% +renovations for example this is what i +was saying about the beta on the actual + + align:start position:0% +was saying about the beta on the actual + + + align:start position:0% +was saying about the beta on the actual +market value + + align:start position:0% +market value + + + align:start position:0% +market value +if you systematically underestimate or + + align:start position:0% +if you systematically underestimate or + + + align:start position:0% +if you systematically underestimate or +overestimate how much people renovate + + align:start position:0% +overestimate how much people renovate + + + align:start position:0% +overestimate how much people renovate +and so on or maybe you know the housing + + align:start position:0% +and so on or maybe you know the housing + + + align:start position:0% +and so on or maybe you know the housing +market is really hot or whatever + + align:start position:0% +market is really hot or whatever + + + align:start position:0% +market is really hot or whatever +that's okay the main issue is like that + + align:start position:0% +that's okay the main issue is like that + + + align:start position:0% +that's okay the main issue is like that +can't be correlated with the + + align:start position:0% +can't be correlated with the + + + align:start position:0% +can't be correlated with the +uh uh the loss here so if it's the case + + align:start position:0% +uh uh the loss here so if it's the case + + + align:start position:0% +uh uh the loss here so if it's the case +that people who may + + align:start position:0% +that people who may + + + align:start position:0% +that people who may +who lost a bunch of money in terms of + + align:start position:0% +who lost a bunch of money in terms of + + + align:start position:0% +who lost a bunch of money in terms of +like their housing prices sort of like + + align:start position:0% +like their housing prices sort of like + + + align:start position:0% +like their housing prices sort of like +tanked + + align:start position:0% +tanked + + + align:start position:0% +tanked +uh if those people have done more or + + align:start position:0% +uh if those people have done more or + + + align:start position:0% +uh if those people have done more or +less renovations then you're in trouble + + align:start position:0% +less renovations then you're in trouble + + + align:start position:0% +less renovations then you're in trouble +with your estimates + + align:start position:0% + + + + align:start position:0% + +yeah is the expected selling price the + + align:start position:0% +yeah is the expected selling price the + + + align:start position:0% +yeah is the expected selling price the +estimation of actual work value + + align:start position:0% +estimation of actual work value + + + align:start position:0% +estimation of actual work value +correct okay yes + + align:start position:0% +correct okay yes + + + align:start position:0% +correct okay yes +um so now what what generation meyer + + align:start position:0% +um so now what what generation meyer + + + align:start position:0% +um so now what what generation meyer +find is and there's more detail to that + + align:start position:0% +find is and there's more detail to that + + + align:start position:0% +find is and there's more detail to that +but essentially the main finding is and + + align:start position:0% +but essentially the main finding is and + + + align:start position:0% +but essentially the main finding is and +that's a + + align:start position:0% +that's a + + + align:start position:0% +that's a +fairly solid one there's a bunch of + + align:start position:0% +fairly solid one there's a bunch of + + + align:start position:0% +fairly solid one there's a bunch of +different specifications is a 10 + + align:start position:0% +different specifications is a 10 + + + align:start position:0% +different specifications is a 10 +increase in a perspective loss if this + + align:start position:0% +increase in a perspective loss if this + + + align:start position:0% +increase in a perspective loss if this +loss coefficient the difference between + + align:start position:0% +loss coefficient the difference between + + + align:start position:0% +loss coefficient the difference between +the expected selling price and the uh + + align:start position:0% +the expected selling price and the uh + + + align:start position:0% +the expected selling price and the uh +purchase price + + align:start position:0% +purchase price + + + align:start position:0% +purchase price +uh if that's 10 percent higher than + + align:start position:0% +uh if that's 10 percent higher than + + + align:start position:0% +uh if that's 10 percent higher than +essentially the list price is 2.5 to 3 + + align:start position:0% +essentially the list price is 2.5 to 3 + + + align:start position:0% +essentially the list price is 2.5 to 3 +percent + + align:start position:0% +percent + + + align:start position:0% +percent +uh 3.5 percent higher and then these + + align:start position:0% +uh 3.5 percent higher and then these + + + align:start position:0% +uh 3.5 percent higher and then these +effects so like people list the price + + align:start position:0% +effects so like people list the price + + + align:start position:0% +effects so like people list the price +the house at a higher price if the house + + align:start position:0% +the house at a higher price if the house + + + align:start position:0% +the house at a higher price if the house +is at a loss compared to like a similar + + align:start position:0% +is at a loss compared to like a similar + + + align:start position:0% +is at a loss compared to like a similar +house who's not at a loss or like + + align:start position:0% +house who's not at a loss or like + + + align:start position:0% +house who's not at a loss or like +it was in the game domain these effects + + align:start position:0% +it was in the game domain these effects + + + align:start position:0% +it was in the game domain these effects +then translate + + align:start position:0% +then translate + + + align:start position:0% +then translate +into higher uh sales prices and the + + align:start position:0% +into higher uh sales prices and the + + + align:start position:0% +into higher uh sales prices and the +lower hazard rate of sale + + align:start position:0% +lower hazard rate of sale + + + align:start position:0% +lower hazard rate of sale +that's to say people actually sell it at + + align:start position:0% +that's to say people actually sell it at + + + align:start position:0% +that's to say people actually sell it at +a higher price + + align:start position:0% +a higher price + + + align:start position:0% +a higher price +so it's in fact you know it's hard to + + align:start position:0% +so it's in fact you know it's hard to + + + align:start position:0% +so it's in fact you know it's hard to +say here what's optimal versus not it + + align:start position:0% +say here what's optimal versus not it + + + align:start position:0% +say here what's optimal versus not it +could be that overall people are like + + align:start position:0% +could be that overall people are like + + + align:start position:0% +could be that overall people are like +uh you know it's actually a good thing + + align:start position:0% +uh you know it's actually a good thing + + + align:start position:0% +uh you know it's actually a good thing +to do that depends a lot on essentially + + align:start position:0% +to do that depends a lot on essentially + + + align:start position:0% +to do that depends a lot on essentially +like your opportunity costs of + + align:start position:0% +like your opportunity costs of + + + align:start position:0% +like your opportunity costs of +of money in terms of like or you know + + align:start position:0% +of money in terms of like or you know + + + align:start position:0% +of money in terms of like or you know +your how + + align:start position:0% +your how + + + align:start position:0% +your how +costly is it for you to keep the the + + align:start position:0% +costly is it for you to keep the the + + + align:start position:0% +costly is it for you to keep the the +house on the market for a while + + align:start position:0% +house on the market for a while + + + align:start position:0% +house on the market for a while +but essentially um uh people have a + + align:start position:0% +but essentially um uh people have a + + + align:start position:0% +but essentially um uh people have a +lower hazard rate of sales that's to say + + align:start position:0% +lower hazard rate of sales that's to say + + + align:start position:0% +lower hazard rate of sales that's to say +it just takes them a lot longer to sell + + align:start position:0% +it just takes them a lot longer to sell + + + align:start position:0% +it just takes them a lot longer to sell +the house + + align:start position:0% +the house + + + align:start position:0% +the house +that tends to be very costly to do so + + align:start position:0% +that tends to be very costly to do so + + + align:start position:0% +that tends to be very costly to do so +but you know if you you know just + + align:start position:0% +but you know if you you know just + + + align:start position:0% +but you know if you you know just +otherwise would have your money in the + + align:start position:0% +otherwise would have your money in the + + + align:start position:0% +otherwise would have your money in the +bank and you have another place to stay + + align:start position:0% +bank and you have another place to stay + + + align:start position:0% +bank and you have another place to stay +and you don't really care + + align:start position:0% +and you don't really care + + + align:start position:0% +and you don't really care +maybe then that's fine uh but we surely + + align:start position:0% +maybe then that's fine uh but we surely + + + align:start position:0% +maybe then that's fine uh but we surely +have like real effects in terms of like + + align:start position:0% +have like real effects in terms of like + + + align:start position:0% +have like real effects in terms of like +uh people list their houses as high at + + align:start position:0% +uh people list their houses as high at + + + align:start position:0% +uh people list their houses as high at +higher prices people + + align:start position:0% +higher prices people + + + align:start position:0% +higher prices people +sell them at somewhat higher prices and + + align:start position:0% +sell them at somewhat higher prices and + + + align:start position:0% +sell them at somewhat higher prices and +people also keep them longer + + align:start position:0% +people also keep them longer + + + align:start position:0% +people also keep them longer +on the market okay yeah + + align:start position:0% +on the market okay yeah + + + align:start position:0% +on the market okay yeah +is this the same analysis if it's gains + + align:start position:0% +is this the same analysis if it's gains + + + align:start position:0% +is this the same analysis if it's gains +in the + + align:start position:0% +in the + + + align:start position:0% +in the +value of the house + + align:start position:0% + + + + align:start position:0% + +so essentially what we're doing is we're + + align:start position:0% +so essentially what we're doing is we're + + + align:start position:0% +so essentially what we're doing is we're +implicitly comparing losses versus gains + + align:start position:0% +implicitly comparing losses versus gains + + + align:start position:0% +implicitly comparing losses versus gains +right so so that gains + + align:start position:0% +right so so that gains + + + align:start position:0% +right so so that gains +the gains here would be in the actual + + align:start position:0% +the gains here would be in the actual + + + align:start position:0% +the gains here would be in the actual +market value + + align:start position:0% +market value + + + align:start position:0% +market value +already as it is so it's + + align:start position:0% +already as it is so it's + + + align:start position:0% +already as it is so it's +so but essentially what you implicitly + + align:start position:0% +so but essentially what you implicitly + + + align:start position:0% +so but essentially what you implicitly +do is you create when comparing + + align:start position:0% +do is you create when comparing + + + align:start position:0% +do is you create when comparing +implicitly this is what i was saying + + align:start position:0% +implicitly this is what i was saying + + + align:start position:0% +implicitly this is what i was saying +here + + align:start position:0% +here + + + align:start position:0% +here +when you look at this picture implicitly + + align:start position:0% +when you look at this picture implicitly + + + align:start position:0% +when you look at this picture implicitly +what we're doing is we look at people + + align:start position:0% +what we're doing is we look at people + + + align:start position:0% +what we're doing is we look at people +who are + + align:start position:0% +who are + + + align:start position:0% +who are +um losing money compared to people who + + align:start position:0% +um losing money compared to people who + + + align:start position:0% +um losing money compared to people who +are gaining money + + align:start position:0% +are gaining money + + + align:start position:0% +are gaining money +and explicitly implicitly asking like is + + align:start position:0% +and explicitly implicitly asking like is + + + align:start position:0% +and explicitly implicitly asking like is +the increase in the gain sort of + + align:start position:0% +the increase in the gain sort of + + + align:start position:0% +the increase in the gain sort of +predictive of that + + align:start position:0% +predictive of that + + + align:start position:0% +predictive of that +sorry the the increase in the loss is a + + align:start position:0% +sorry the the increase in the loss is a + + + align:start position:0% +sorry the the increase in the loss is a +predictive of like your + + align:start position:0% +predictive of like your + + + align:start position:0% +predictive of like your +uh listing price now it's hard to do + + align:start position:0% +uh listing price now it's hard to do + + + align:start position:0% +uh listing price now it's hard to do +this at the same time + + align:start position:0% +this at the same time + + + align:start position:0% +this at the same time +for for gains because essentially an + + align:start position:0% +for for gains because essentially an + + + align:start position:0% +for for gains because essentially an +increase in the market + + align:start position:0% +increase in the market + + + align:start position:0% +increase in the market +price overall is this like that sort of + + align:start position:0% +price overall is this like that sort of + + + align:start position:0% +price overall is this like that sort of +culinaire + + align:start position:0% +culinaire + + + align:start position:0% +culinaire +in short essentially that's hard to + + align:start position:0% +in short essentially that's hard to + + + align:start position:0% +in short essentially that's hard to +separate you could do the same analysis + + align:start position:0% +separate you could do the same analysis + + + align:start position:0% +separate you could do the same analysis +and you wouldn't find that for the gains + + align:start position:0% +and you wouldn't find that for the gains + + + align:start position:0% +and you wouldn't find that for the gains +in part because + + align:start position:0% +in part because + + + align:start position:0% +in part because +essentially explicitly what we're doing + + align:start position:0% +essentially explicitly what we're doing + + + align:start position:0% +essentially explicitly what we're doing +is increasing losses to gains + + align:start position:0% + + + + align:start position:0% + +okay uh okay so then there's another + + align:start position:0% +okay uh okay so then there's another + + + align:start position:0% +okay uh okay so then there's another +piece of evidence that sort of tells us + + align:start position:0% +piece of evidence that sort of tells us + + + align:start position:0% +piece of evidence that sort of tells us +perhaps this is not optimal if you look + + align:start position:0% +perhaps this is not optimal if you look + + + align:start position:0% +perhaps this is not optimal if you look +at people who are + + align:start position:0% +at people who are + + + align:start position:0% +at people who are +owner occupied compared to investors so + + align:start position:0% +owner occupied compared to investors so + + + align:start position:0% +owner occupied compared to investors so +they're people who essentially invest in + + align:start position:0% +they're people who essentially invest in + + + align:start position:0% +they're people who essentially invest in +houses and they sell houses and they + + align:start position:0% +houses and they sell houses and they + + + align:start position:0% +houses and they sell houses and they +sell lots of houses over time + + align:start position:0% +sell lots of houses over time + + + align:start position:0% +sell lots of houses over time +those people have much lower uh + + align:start position:0% +those people have much lower uh + + + align:start position:0% +those people have much lower uh +endowment effects if you want for houses + + align:start position:0% +endowment effects if you want for houses + + + align:start position:0% +endowment effects if you want for houses +so they exhibit this behavior a lot less + + align:start position:0% +so they exhibit this behavior a lot less + + + align:start position:0% +so they exhibit this behavior a lot less +but people who live in that house who + + align:start position:0% +but people who live in that house who + + + align:start position:0% +but people who live in that house who +bought that house for them it's mostly + + align:start position:0% +bought that house for them it's mostly + + + align:start position:0% +bought that house for them it's mostly +like the only house they live in it's + + align:start position:0% +like the only house they live in it's + + + align:start position:0% +like the only house they live in it's +the main purchase that they have + + align:start position:0% +the main purchase that they have + + + align:start position:0% +the main purchase that they have +for them it's essentially their house + + align:start position:0% +for them it's essentially their house + + + align:start position:0% +for them it's essentially their house +for which they don't want to make + + align:start position:0% + + + + align:start position:0% + +a losses for them these effects are + + align:start position:0% +a losses for them these effects are + + + align:start position:0% +a losses for them these effects are +twice as large compared to the + + align:start position:0% +twice as large compared to the + + + align:start position:0% +twice as large compared to the +investors and that's perhaps some + + align:start position:0% +investors and that's perhaps some + + + align:start position:0% +investors and that's perhaps some +evidence that uh this is not optimal + + align:start position:0% +evidence that uh this is not optimal + + + align:start position:0% +evidence that uh this is not optimal +behavior in a sense of the + + align:start position:0% +behavior in a sense of the + + + align:start position:0% +behavior in a sense of the +sort of the professional investors they + + align:start position:0% +sort of the professional investors they + + + align:start position:0% +sort of the professional investors they +presumably know pretty well + + align:start position:0% +presumably know pretty well + + + align:start position:0% +presumably know pretty well +uh how to price their houses so if they + + align:start position:0% +uh how to price their houses so if they + + + align:start position:0% +uh how to price their houses so if they +do this behavior less + + align:start position:0% +do this behavior less + + + align:start position:0% +do this behavior less +uh presumably that's that's a sign that + + align:start position:0% +uh presumably that's that's a sign that + + + align:start position:0% +uh presumably that's that's a sign that +that there's some form of a mistake here + + align:start position:0% +that there's some form of a mistake here + + + align:start position:0% +that there's some form of a mistake here +um going on + + align:start position:0% + + + + align:start position:0% + +second there's some evidence in john + + align:start position:0% +second there's some evidence in john + + + align:start position:0% +second there's some evidence in john +list has some work on this + + align:start position:0% +list has some work on this + + + align:start position:0% +list has some work on this +overall is to say that experience can + + align:start position:0% +overall is to say that experience can + + + align:start position:0% +overall is to say that experience can +mitigate reference dependent + + align:start position:0% +mitigate reference dependent + + + align:start position:0% +mitigate reference dependent +effects essentially if you do a lot of + + align:start position:0% +effects essentially if you do a lot of + + + align:start position:0% +effects essentially if you do a lot of +trading if you sell a lot of houses and + + align:start position:0% +trading if you sell a lot of houses and + + + align:start position:0% +trading if you sell a lot of houses and +so on + + align:start position:0% +so on + + + align:start position:0% +so on +then you might still feel losses of + + align:start position:0% +then you might still feel losses of + + + align:start position:0% +then you might still feel losses of +losses and gains + + align:start position:0% +losses and gains + + + align:start position:0% +losses and gains +but you might sort of have a lot more + + align:start position:0% +but you might sort of have a lot more + + + align:start position:0% +but you might sort of have a lot more +experience with this you kind of know + + align:start position:0% +experience with this you kind of know + + + align:start position:0% +experience with this you kind of know +that this is happening sometimes + + align:start position:0% +that this is happening sometimes + + + align:start position:0% +that this is happening sometimes +and you might be less prone to these + + align:start position:0% +and you might be less prone to these + + + align:start position:0% +and you might be less prone to these +types of effects because you kind of + + align:start position:0% +types of effects because you kind of + + + align:start position:0% +types of effects because you kind of +know that you shouldn't be doing + + align:start position:0% +know that you shouldn't be doing + + + align:start position:0% +know that you shouldn't be doing +this you shouldn't sort of have your + + align:start position:0% +this you shouldn't sort of have your + + + align:start position:0% +this you shouldn't sort of have your +feelings of losses and gains + + align:start position:0% +feelings of losses and gains + + + align:start position:0% +feelings of losses and gains +get in the way of making profits so + + align:start position:0% +get in the way of making profits so + + + align:start position:0% +get in the way of making profits so +there's some people who would argue that + + align:start position:0% +there's some people who would argue that + + + align:start position:0% +there's some people who would argue that +this is very much consistent with like + + align:start position:0% +this is very much consistent with like + + + align:start position:0% +this is very much consistent with like +markets over time or exposures to + + align:start position:0% +markets over time or exposures to + + + align:start position:0% +markets over time or exposures to +markets and several predictions + + align:start position:0% +markets and several predictions + + + align:start position:0% +markets and several predictions +experience + + align:start position:0% +experience + + + align:start position:0% +experience +makes some of these effects go away and + + align:start position:0% +makes some of these effects go away and + + + align:start position:0% +makes some of these effects go away and +john list has some + + align:start position:0% +john list has some + + + align:start position:0% +john list has some +separate evidence on this on traders of + + align:start position:0% +separate evidence on this on traders of + + + align:start position:0% +separate evidence on this on traders of +cards and so on + + align:start position:0% + + + + align:start position:0% + +okay so now next we're going to talk a + + align:start position:0% +okay so now next we're going to talk a + + + align:start position:0% +okay so now next we're going to talk a +little bit about finance and stocks + + align:start position:0% +little bit about finance and stocks + + + align:start position:0% +little bit about finance and stocks +so interestingly yeah sorry on the + + align:start position:0% +so interestingly yeah sorry on the + + + align:start position:0% +so interestingly yeah sorry on the +previous um study why is this a + + align:start position:0% +previous um study why is this a + + + align:start position:0% +previous um study why is this a +reference dependence + + align:start position:0% +reference dependence + + + align:start position:0% +reference dependence +on information um owner and i + + align:start position:0% +on information um owner and i + + + align:start position:0% +on information um owner and i +think that my house is worth this amount + + align:start position:0% +think that my house is worth this amount + + + align:start position:0% +think that my house is worth this amount +and i'm just + + align:start position:0% +and i'm just + + + align:start position:0% +and i'm just +really anchored to believing that that's + + align:start position:0% +really anchored to believing that that's + + + align:start position:0% +really anchored to believing that that's +the problem + + align:start position:0% +the problem + + + align:start position:0% +the problem +right so one thing you could say is like + + align:start position:0% +right so one thing you could say is like + + + align:start position:0% +right so one thing you could say is like +that uh so what you always have to make + + align:start position:0% +that uh so what you always have to make + + + align:start position:0% +that uh so what you always have to make +the argument is like people who are + + align:start position:0% +the argument is like people who are + + + align:start position:0% +the argument is like people who are +losses compared to who are at gains so + + align:start position:0% +losses compared to who are at gains so + + + align:start position:0% +losses compared to who are at gains so +you look at your + + align:start position:0% +you look at your + + + align:start position:0% +you look at your +investor a and b they might have like + + align:start position:0% +investor a and b they might have like + + + align:start position:0% +investor a and b they might have like +additional information + + align:start position:0% +additional information + + + align:start position:0% +additional information +on uh how much the house is worth so it + + align:start position:0% +on uh how much the house is worth so it + + + align:start position:0% +on uh how much the house is worth so it +could be for example that seller a + + align:start position:0% +could be for example that seller a + + + align:start position:0% +could be for example that seller a +knows a lot about this house it's like + + align:start position:0% +knows a lot about this house it's like + + + align:start position:0% +knows a lot about this house it's like +very beautiful and so much light and + + align:start position:0% +very beautiful and so much light and + + + align:start position:0% +very beautiful and so much light and +this and that + + align:start position:0% +this and that + + + align:start position:0% +this and that +um and therefore they paid a lot + + align:start position:0% +um and therefore they paid a lot + + + align:start position:0% +um and therefore they paid a lot +therefore they have private information + + align:start position:0% +therefore they have private information + + + align:start position:0% +therefore they have private information +that it's worth a lot + + align:start position:0% +that it's worth a lot + + + align:start position:0% +that it's worth a lot +therefore they listed at a really high + + align:start position:0% +therefore they listed at a really high + + + align:start position:0% +therefore they listed at a really high +price so there's some specification here + + align:start position:0% +price so there's some specification here + + + align:start position:0% +price so there's some specification here +that look at this + + align:start position:0% +that look at this + + + align:start position:0% +that look at this +what you see is this is like columns two + + align:start position:0% +what you see is this is like columns two + + + align:start position:0% +what you see is this is like columns two +four and six + + align:start position:0% +four and six + + + align:start position:0% +four and six +which is uh the residual from the last + + align:start position:0% +which is uh the residual from the last + + + align:start position:0% +which is uh the residual from the last +sales price + + align:start position:0% +sales price + + + align:start position:0% +sales price +what is that that's essentially the + + align:start position:0% +what is that that's essentially the + + + align:start position:0% +what is that that's essentially the +difference between at the + + align:start position:0% +difference between at the + + + align:start position:0% +difference between at the +time when previously the house was sold + + align:start position:0% +time when previously the house was sold + + + align:start position:0% +time when previously the house was sold +what was the prediction of the market + + align:start position:0% +what was the prediction of the market + + + align:start position:0% +what was the prediction of the market +price then and how much was it sold so + + align:start position:0% +price then and how much was it sold so + + + align:start position:0% +price then and how much was it sold so +it's kind of like how much did you + + align:start position:0% +it's kind of like how much did you + + + align:start position:0% +it's kind of like how much did you +over uh uh how much did you overpay if + + align:start position:0% +over uh uh how much did you overpay if + + + align:start position:0% +over uh uh how much did you overpay if +you want relative to what we expected at + + align:start position:0% +you want relative to what we expected at + + + align:start position:0% +you want relative to what we expected at +the time + + align:start position:0% +the time + + + align:start position:0% +the time +presumably that's reflective again using + + align:start position:0% +presumably that's reflective again using + + + align:start position:0% +presumably that's reflective again using +the same prediction method + + align:start position:0% +the same prediction method + + + align:start position:0% +the same prediction method +so if you thought you know it's really + + align:start position:0% +so if you thought you know it's really + + + align:start position:0% +so if you thought you know it's really +beautiful and lots of windows and this + + align:start position:0% +beautiful and lots of windows and this + + + align:start position:0% +beautiful and lots of windows and this +and that lots of light and + + align:start position:0% +and that lots of light and + + + align:start position:0% +and that lots of light and +really quiet and so on if you overpaid + + align:start position:0% +really quiet and so on if you overpaid + + + align:start position:0% +really quiet and so on if you overpaid +at the time + + align:start position:0% +at the time + + + align:start position:0% +at the time +that should then sort of pre predictive + + align:start position:0% +that should then sort of pre predictive + + + align:start position:0% +that should then sort of pre predictive +of the listing price + + align:start position:0% +of the listing price + + + align:start position:0% +of the listing price +and sort of controlling for that then + + align:start position:0% +and sort of controlling for that then + + + align:start position:0% +and sort of controlling for that then +should make this go away + + align:start position:0% +should make this go away + + + align:start position:0% +should make this go away +what you see however is this is um + + align:start position:0% +what you see however is this is um + + + align:start position:0% +what you see however is this is um +there's some of that perhaps going on if + + align:start position:0% +there's some of that perhaps going on if + + + align:start position:0% +there's some of that perhaps going on if +you + + align:start position:0% +you + + + align:start position:0% +you +compare for example columns one and two + + align:start position:0% +compare for example columns one and two + + + align:start position:0% +compare for example columns one and two +you see that the effects goes down a + + align:start position:0% +you see that the effects goes down a + + + align:start position:0% +you see that the effects goes down a +little bit but it's still there quite a + + align:start position:0% +little bit but it's still there quite a + + + align:start position:0% +little bit but it's still there quite a +bit what's this is why i was saying like + + align:start position:0% +bit what's this is why i was saying like + + + align:start position:0% +bit what's this is why i was saying like +25 to 35 percent + + align:start position:0% +25 to 35 percent + + + align:start position:0% +25 to 35 percent +uh that is exactly right that's a big + + align:start position:0% +uh that is exactly right that's a big + + + align:start position:0% +uh that is exactly right that's a big +concern and there's a bunch of sort of + + align:start position:0% +concern and there's a bunch of sort of + + + align:start position:0% +concern and there's a bunch of sort of +robustness et cetera checks in this + + align:start position:0% +robustness et cetera checks in this + + + align:start position:0% +robustness et cetera checks in this +specific study + + align:start position:0% +specific study + + + align:start position:0% +specific study +but that's exactly right there could be + + align:start position:0% +but that's exactly right there could be + + + align:start position:0% +but that's exactly right there could be +sort of unobservable information that + + align:start position:0% +sort of unobservable information that + + + align:start position:0% +sort of unobservable information that +the + + align:start position:0% +the + + + align:start position:0% +the +uh owner might have about the house that + + align:start position:0% +uh owner might have about the house that + + + align:start position:0% +uh owner might have about the house that +is not in zillow or in any sort of + + align:start position:0% +is not in zillow or in any sort of + + + align:start position:0% +is not in zillow or in any sort of +return etc + + align:start position:0% +return etc + + + align:start position:0% +return etc +predictions that's available for the + + align:start position:0% +predictions that's available for the + + + align:start position:0% +predictions that's available for the +public that's a great question but i + + align:start position:0% +public that's a great question but i + + + align:start position:0% +public that's a great question but i +think it's + + align:start position:0% +think it's + + + align:start position:0% +think it's +uh to the extent that that takes care of + + align:start position:0% +uh to the extent that that takes care of + + + align:start position:0% +uh to the extent that that takes care of +it it's sort of uh the authors have + + align:start position:0% +it it's sort of uh the authors have + + + align:start position:0% +it it's sort of uh the authors have +thought about that uh yes um on the + + align:start position:0% +thought about that uh yes um on the + + + align:start position:0% +thought about that uh yes um on the +following slide + + align:start position:0% +following slide + + + align:start position:0% +following slide +when you talk about the differences + + align:start position:0% +when you talk about the differences + + + align:start position:0% +when you talk about the differences +it's how do you control for like the + + align:start position:0% +it's how do you control for like the + + + align:start position:0% +it's how do you control for like the +selection bias about the people that + + align:start position:0% +selection bias about the people that + + + align:start position:0% +selection bias about the people that +may be the ones repeatedly selling + + align:start position:0% +may be the ones repeatedly selling + + + align:start position:0% +may be the ones repeatedly selling +houses + + align:start position:0% +houses + + + align:start position:0% +houses +exhibit this last and therefore like + + align:start position:0% +exhibit this last and therefore like + + + align:start position:0% +exhibit this last and therefore like +stay in the market + + align:start position:0% +stay in the market + + + align:start position:0% +stay in the market +versus a change in those individuals + + align:start position:0% +versus a change in those individuals + + + align:start position:0% +versus a change in those individuals +behavior + + align:start position:0% + + + + align:start position:0% + +right that's a great question so the + + align:start position:0% +right that's a great question so the + + + align:start position:0% +right that's a great question so the +question you're asking is essentially to + + align:start position:0% +question you're asking is essentially to + + + align:start position:0% +question you're asking is essentially to +say + + align:start position:0% +say + + + align:start position:0% +say +and that's in fact a great um sort of a + + align:start position:0% +and that's in fact a great um sort of a + + + align:start position:0% +and that's in fact a great um sort of a +segue into like behavioral finance which + + align:start position:0% +segue into like behavioral finance which + + + align:start position:0% +segue into like behavioral finance which +is to say suppose there's some people + + align:start position:0% +is to say suppose there's some people + + + align:start position:0% +is to say suppose there's some people +who are really sophisticated + + align:start position:0% +who are really sophisticated + + + align:start position:0% +who are really sophisticated +they don't have certain uh behavioral + + align:start position:0% +they don't have certain uh behavioral + + + align:start position:0% +they don't have certain uh behavioral +biases maybe they're not philosophers + + align:start position:0% +biases maybe they're not philosophers + + + align:start position:0% +biases maybe they're not philosophers +that makes you like a better investor + + align:start position:0% +that makes you like a better investor + + + align:start position:0% +that makes you like a better investor +say and therefore you stay in the market + + align:start position:0% +say and therefore you stay in the market + + + align:start position:0% +say and therefore you stay in the market +overall i think from this observation + + align:start position:0% +overall i think from this observation + + + align:start position:0% +overall i think from this observation +that i have here i cannot tell you is it + + align:start position:0% +that i have here i cannot tell you is it + + + align:start position:0% +that i have here i cannot tell you is it +like select is it just + + align:start position:0% +like select is it just + + + align:start position:0% +like select is it just +is it just that people um + + align:start position:0% +is it just that people um + + + align:start position:0% +is it just that people um +is it experience or is it selection so + + align:start position:0% +is it experience or is it selection so + + + align:start position:0% +is it experience or is it selection so +the question kind of is + + align:start position:0% +the question kind of is + + + align:start position:0% +the question kind of is +when people are investors + + align:start position:0% +when people are investors + + + align:start position:0% +when people are investors +do they do the effects of reference + + align:start position:0% +do they do the effects of reference + + + align:start position:0% +do they do the effects of reference +dependence of gains and losses go over + + align:start position:0% +dependence of gains and losses go over + + + align:start position:0% +dependence of gains and losses go over +go away over time essentially like maybe + + align:start position:0% +go away over time essentially like maybe + + + align:start position:0% +go away over time essentially like maybe +the first second third time i feel like + + align:start position:0% +the first second third time i feel like + + + align:start position:0% +the first second third time i feel like +really a loss in terms of making a + + align:start position:0% +really a loss in terms of making a + + + align:start position:0% +really a loss in terms of making a +bad investment but in number house + + align:start position:0% +bad investment but in number house + + + align:start position:0% +bad investment but in number house +number 20 i'm just like that's like as + + align:start position:0% +number 20 i'm just like that's like as + + + align:start position:0% +number 20 i'm just like that's like as +usual and i shouldn't + + align:start position:0% +usual and i shouldn't + + + align:start position:0% +usual and i shouldn't +really care very much is it that this + + align:start position:0% +really care very much is it that this + + + align:start position:0% +really care very much is it that this +goes away or is it that like the people + + align:start position:0% +goes away or is it that like the people + + + align:start position:0% +goes away or is it that like the people +who are particularly lost a verse and + + align:start position:0% +who are particularly lost a verse and + + + align:start position:0% +who are particularly lost a verse and +sort of essentially + + align:start position:0% +sort of essentially + + + align:start position:0% +sort of essentially +uh engage in this type of behavior in + + align:start position:0% +uh engage in this type of behavior in + + + align:start position:0% +uh engage in this type of behavior in +terms of like uh + + align:start position:0% +terms of like uh + + + align:start position:0% +terms of like uh +over uh listing too high of a price um + + align:start position:0% +over uh listing too high of a price um + + + align:start position:0% +over uh listing too high of a price um +for losses + + align:start position:0% +for losses + + + align:start position:0% +for losses +these are sort of like that investor in + + align:start position:0% +these are sort of like that investor in + + + align:start position:0% +these are sort of like that investor in +the housing markets and they sort of + + align:start position:0% +the housing markets and they sort of + + + align:start position:0% +the housing markets and they sort of +are essentially driven out of the market + + align:start position:0% +are essentially driven out of the market + + + align:start position:0% +are essentially driven out of the market +so that specific setting um i don't + + align:start position:0% +so that specific setting um i don't + + + align:start position:0% +so that specific setting um i don't +think we can necessarily + + align:start position:0% +think we can necessarily + + + align:start position:0% +think we can necessarily +account for that i think in the uh + + align:start position:0% +account for that i think in the uh + + + align:start position:0% +account for that i think in the uh +studies by john list it's very much + + align:start position:0% +studies by john list it's very much + + + align:start position:0% +studies by john list it's very much +people argue it's about + + align:start position:0% +people argue it's about + + + align:start position:0% +people argue it's about +experience but again there could also + + align:start position:0% +experience but again there could also + + + align:start position:0% +experience but again there could also +some part could also be a + + align:start position:0% +some part could also be a + + + align:start position:0% +some part could also be a +selection i think so now in the + + align:start position:0% +selection i think so now in the + + + align:start position:0% +selection i think so now in the +so i think in some sense either way + + align:start position:0% +so i think in some sense either way + + + align:start position:0% +so i think in some sense either way +um uh uh i think the the evidence that + + align:start position:0% +um uh uh i think the the evidence that + + + align:start position:0% +um uh uh i think the the evidence that +the investors are doing this behavior + + align:start position:0% +the investors are doing this behavior + + + align:start position:0% +the investors are doing this behavior +last sort of tells us something about + + align:start position:0% +last sort of tells us something about + + + align:start position:0% +last sort of tells us something about +like + + align:start position:0% +like + + + align:start position:0% +like +this is probably not at least + + align:start position:0% +this is probably not at least + + + align:start position:0% +this is probably not at least +financially optimal + + align:start position:0% +financially optimal + + + align:start position:0% +financially optimal +for you to engage in this type of + + align:start position:0% +for you to engage in this type of + + + align:start position:0% +for you to engage in this type of +behavior it might be privately optimal + + align:start position:0% +behavior it might be privately optimal + + + align:start position:0% +behavior it might be privately optimal +in some sense if you really feel bad at + + align:start position:0% +in some sense if you really feel bad at + + + align:start position:0% +in some sense if you really feel bad at +like selling your house at a loss you + + align:start position:0% +like selling your house at a loss you + + + align:start position:0% +like selling your house at a loss you +should probably + + align:start position:0% +should probably + + + align:start position:0% +should probably +list it at a higher price because that + + align:start position:0% +list it at a higher price because that + + + align:start position:0% +list it at a higher price because that +sort of limits you your losses + + align:start position:0% +sort of limits you your losses + + + align:start position:0% +sort of limits you your losses +that's just what the utility function + + align:start position:0% +that's just what the utility function + + + align:start position:0% +that's just what the utility function +looks like it's not necessarily a + + align:start position:0% +looks like it's not necessarily a + + + align:start position:0% +looks like it's not necessarily a +and the sub-optimal in the sense of like + + align:start position:0% +and the sub-optimal in the sense of like + + + align:start position:0% +and the sub-optimal in the sense of like +uh how you feel afterwards + + align:start position:0% +uh how you feel afterwards + + + align:start position:0% +uh how you feel afterwards +it might be sub-optimal in terms of like + + align:start position:0% +it might be sub-optimal in terms of like + + + align:start position:0% +it might be sub-optimal in terms of like +how much money you make or how much + + align:start position:0% +how much money you make or how much + + + align:start position:0% +how much money you make or how much +money you have eventually + + align:start position:0% +money you have eventually + + + align:start position:0% +money you have eventually +uh on how much you pay for keeping your + + align:start position:0% +uh on how much you pay for keeping your + + + align:start position:0% +uh on how much you pay for keeping your +house on the market and so on + + align:start position:0% +house on the market and so on + + + align:start position:0% +house on the market and so on +for an extended period of time um okay + + align:start position:0% +for an extended period of time um okay + + + align:start position:0% +for an extended period of time um okay +so does that answer your question no + + align:start position:0% +so does that answer your question no + + + align:start position:0% +so does that answer your question no +yeah okay + + align:start position:0% +yeah okay + + + align:start position:0% +yeah okay +so um so behavioral finance is an + + align:start position:0% +so um so behavioral finance is an + + + align:start position:0% +so um so behavioral finance is an +interesting field because + + align:start position:0% +interesting field because + + + align:start position:0% +interesting field because +for quite a while economists thought + + align:start position:0% +for quite a while economists thought + + + align:start position:0% +for quite a while economists thought +that sort of neoclassical assumptions + + align:start position:0% +that sort of neoclassical assumptions + + + align:start position:0% +that sort of neoclassical assumptions +are in fact most likely to hold in + + align:start position:0% +are in fact most likely to hold in + + + align:start position:0% +are in fact most likely to hold in +financial markets and why is that + + align:start position:0% +financial markets and why is that + + + align:start position:0% +financial markets and why is that +why do we think what and some of this + + align:start position:0% +why do we think what and some of this + + + align:start position:0% +why do we think what and some of this +already i mentioned but + + align:start position:0% +already i mentioned but + + + align:start position:0% +already i mentioned but +why are financial markets + + align:start position:0% +why are financial markets + + + align:start position:0% +why are financial markets +particular why might i think that + + align:start position:0% +particular why might i think that + + + align:start position:0% +particular why might i think that +financial markets are particularly + + align:start position:0% + + + + align:start position:0% + +efficient + + align:start position:0% + + + + align:start position:0% + +yes well you might think that financial + + align:start position:0% +yes well you might think that financial + + + align:start position:0% +yes well you might think that financial +markets are very competitive + + align:start position:0% +markets are very competitive + + + align:start position:0% +markets are very competitive +and so it's actually the ones who can + + align:start position:0% +and so it's actually the ones who can + + + align:start position:0% +and so it's actually the ones who can +get rid of their behavioral biases that + + align:start position:0% +get rid of their behavioral biases that + + + align:start position:0% +get rid of their behavioral biases that +benefit + + align:start position:0% + + + + align:start position:0% + +exactly so it's very much like sort of + + align:start position:0% +exactly so it's very much like sort of + + + align:start position:0% +exactly so it's very much like sort of +the chicago + + align:start position:0% +the chicago + + + align:start position:0% +the chicago +economics assumption is to say so uh + + align:start position:0% +economics assumption is to say so uh + + + align:start position:0% +economics assumption is to say so uh +financial markets are extremely + + align:start position:0% +financial markets are extremely + + + align:start position:0% +financial markets are extremely +competitive if now i'm an investor + + align:start position:0% +competitive if now i'm an investor + + + align:start position:0% +competitive if now i'm an investor +who has various behavioral biases + + align:start position:0% +who has various behavioral biases + + + align:start position:0% +who has various behavioral biases +presumably i'm going to lose some money + + align:start position:0% +presumably i'm going to lose some money + + + align:start position:0% +presumably i'm going to lose some money +one way or the other + + align:start position:0% +one way or the other + + + align:start position:0% +one way or the other +well if markets are really competitive + + align:start position:0% +well if markets are really competitive + + + align:start position:0% +well if markets are really competitive +in the long run i cannot stay in this + + align:start position:0% +in the long run i cannot stay in this + + + align:start position:0% +in the long run i cannot stay in this +market without sort of being + + align:start position:0% +market without sort of being + + + align:start position:0% +market without sort of being +a driven out so essentially the market + + align:start position:0% +a driven out so essentially the market + + + align:start position:0% +a driven out so essentially the market +favor sort of + + align:start position:0% +favor sort of + + + align:start position:0% +favor sort of +results oriented rational and selfish + + align:start position:0% +results oriented rational and selfish + + + align:start position:0% +results oriented rational and selfish +behavior so people are not rational and + + align:start position:0% +behavior so people are not rational and + + + align:start position:0% +behavior so people are not rational and +so on and so forth will be eliminated + + align:start position:0% +so on and so forth will be eliminated + + + align:start position:0% +so on and so forth will be eliminated +from the market + + align:start position:0% +from the market + + + align:start position:0% +from the market +eventually there's two parts to that + + align:start position:0% +eventually there's two parts to that + + + align:start position:0% +eventually there's two parts to that +that's true like across firms that's to + + align:start position:0% +that's true like across firms that's to + + + align:start position:0% +that's true like across firms that's to +say like you know there's some firms + + align:start position:0% +say like you know there's some firms + + + align:start position:0% +say like you know there's some firms +that are better than others + + align:start position:0% +that are better than others + + + align:start position:0% +that are better than others +but also within the firm if i'm an + + align:start position:0% +but also within the firm if i'm an + + + align:start position:0% +but also within the firm if i'm an +investor and i'm sort of like um + + align:start position:0% +investor and i'm sort of like um + + + align:start position:0% +investor and i'm sort of like um +advising clients and the like and i'm + + align:start position:0% +advising clients and the like and i'm + + + align:start position:0% +advising clients and the like and i'm +sort of not very good at this and like + + align:start position:0% +sort of not very good at this and like + + + align:start position:0% +sort of not very good at this and like +essentially i have certain payable + + align:start position:0% +essentially i have certain payable + + + align:start position:0% +essentially i have certain payable +biases that are not optimal in terms of + + align:start position:0% +biases that are not optimal in terms of + + + align:start position:0% +biases that are not optimal in terms of +like making + + align:start position:0% +like making + + + align:start position:0% +like making +money for people presumably i will not + + align:start position:0% +money for people presumably i will not + + + align:start position:0% +money for people presumably i will not +be promoted presumably i will be driven + + align:start position:0% +be promoted presumably i will be driven + + + align:start position:0% +be promoted presumably i will be driven +out of force fired from the + + align:start position:0% +out of force fired from the + + + align:start position:0% +out of force fired from the +the company um eventually so + + align:start position:0% +the company um eventually so + + + align:start position:0% +the company um eventually so +surprisingly in fact + + align:start position:0% +surprisingly in fact + + + align:start position:0% +surprisingly in fact +finance became one of the most + + align:start position:0% +finance became one of the most + + + align:start position:0% +finance became one of the most +influential and most fruitful + + align:start position:0% +influential and most fruitful + + + align:start position:0% +influential and most fruitful +applications of be able + + align:start position:0% +applications of be able + + + align:start position:0% +applications of be able +of the psychology and economics so + + align:start position:0% +of the psychology and economics so + + + align:start position:0% +of the psychology and economics so +behavioral economics there's lots and + + align:start position:0% +behavioral economics there's lots and + + + align:start position:0% +behavioral economics there's lots and +lots of work in behavioral finance + + align:start position:0% +lots of work in behavioral finance + + + align:start position:0% +lots of work in behavioral finance +the reason being perhaps not necessarily + + align:start position:0% +the reason being perhaps not necessarily + + + align:start position:0% +the reason being perhaps not necessarily +because people are um so some people are + + align:start position:0% +because people are um so some people are + + + align:start position:0% +because people are um so some people are +presumably driven out of the market but + + align:start position:0% +presumably driven out of the market but + + + align:start position:0% +presumably driven out of the market but +surely not everyone + + align:start position:0% +surely not everyone + + + align:start position:0% +surely not everyone +but in particular because there's like + + align:start position:0% +but in particular because there's like + + + align:start position:0% +but in particular because there's like +great data in finance like there's lots + + align:start position:0% +great data in finance like there's lots + + + align:start position:0% +great data in finance like there's lots +and lots of daily data in terms of like + + align:start position:0% +and lots of daily data in terms of like + + + align:start position:0% +and lots of daily data in terms of like +things that you should be doing compared + + align:start position:0% +things that you should be doing compared + + + align:start position:0% +things that you should be doing compared +to like what models would say + + align:start position:0% +to like what models would say + + + align:start position:0% +to like what models would say +so it's a really great way of like being + + align:start position:0% +so it's a really great way of like being + + + align:start position:0% +so it's a really great way of like being +able to test models or test essentially + + align:start position:0% +able to test models or test essentially + + + align:start position:0% +able to test models or test essentially +predictions of the neoclassical model or + + align:start position:0% +predictions of the neoclassical model or + + + align:start position:0% +predictions of the neoclassical model or +behavioral theories and so on + + align:start position:0% +behavioral theories and so on + + + align:start position:0% +behavioral theories and so on +so that's why behavioral finance has + + align:start position:0% +so that's why behavioral finance has + + + align:start position:0% +so that's why behavioral finance has +been very influential + + align:start position:0% +been very influential + + + align:start position:0% +been very influential +because there's so much data available + + align:start position:0% +because there's so much data available + + + align:start position:0% +because there's so much data available +for people to in fact + + align:start position:0% +for people to in fact + + + align:start position:0% +for people to in fact +test theories and then you know why is + + align:start position:0% +test theories and then you know why is + + + align:start position:0% +test theories and then you know why is +it that people are not entirely driven + + align:start position:0% +it that people are not entirely driven + + + align:start position:0% +it that people are not entirely driven +out + + align:start position:0% +out + + + align:start position:0% +out +i think often the case is that even if + + align:start position:0% +i think often the case is that even if + + + align:start position:0% +i think often the case is that even if +you're right for example even if you + + align:start position:0% +you're right for example even if you + + + align:start position:0% +you're right for example even if you +write that you can + + align:start position:0% +write that you can + + + align:start position:0% +write that you can +predict and if you watch some like um + + align:start position:0% +predict and if you watch some like um + + + align:start position:0% +predict and if you watch some like um +movies on the financial crisis and so on + + align:start position:0% +movies on the financial crisis and so on + + + align:start position:0% +movies on the financial crisis and so on +even if you're + + align:start position:0% +even if you're + + + align:start position:0% +even if you're +right about like in the long run the + + align:start position:0% +right about like in the long run the + + + align:start position:0% +right about like in the long run the +market is going to tank well actually + + align:start position:0% +market is going to tank well actually + + + align:start position:0% +market is going to tank well actually +it's going to take you a lot of money + + align:start position:0% +it's going to take you a lot of money + + + align:start position:0% +it's going to take you a lot of money +and then you know often you know if + + align:start position:0% +and then you know often you know if + + + align:start position:0% +and then you know often you know if +everybody is wrong + + align:start position:0% +everybody is wrong + + + align:start position:0% +everybody is wrong +prices will go up for quite a while so + + align:start position:0% +prices will go up for quite a while so + + + align:start position:0% +prices will go up for quite a while so +it's not actually clear that in the + + align:start position:0% +it's not actually clear that in the + + + align:start position:0% +it's not actually clear that in the +at least in the short medium run we'll + + align:start position:0% +at least in the short medium run we'll + + + align:start position:0% +at least in the short medium run we'll +be driven out of the market um + + align:start position:0% +be driven out of the market um + + + align:start position:0% +be driven out of the market um +uh uh quickly but that's sort of a + + align:start position:0% +uh uh quickly but that's sort of a + + + align:start position:0% +uh uh quickly but that's sort of a +separate topic + + align:start position:0% +separate topic + + + align:start position:0% +separate topic +okay so now um one uh a reason why or + + align:start position:0% +okay so now um one uh a reason why or + + + align:start position:0% +okay so now um one uh a reason why or +one way in which reference dependent + + align:start position:0% +one way in which reference dependent + + + align:start position:0% +one way in which reference dependent +behavior might be important in finance + + align:start position:0% +behavior might be important in finance + + + align:start position:0% +behavior might be important in finance +is uh people might be differentially + + align:start position:0% +is uh people might be differentially + + + align:start position:0% +is uh people might be differentially +likely to sell winners and hold on to + + align:start position:0% +likely to sell winners and hold on to + + + align:start position:0% +likely to sell winners and hold on to +losers + + align:start position:0% +losers + + + align:start position:0% +losers +uh financial stocks that was mentioned + + align:start position:0% +uh financial stocks that was mentioned + + + align:start position:0% +uh financial stocks that was mentioned +last time as well + + align:start position:0% +last time as well + + + align:start position:0% +last time as well +so what terry odin did in 1997 is like + + align:start position:0% +so what terry odin did in 1997 is like + + + align:start position:0% +so what terry odin did in 1997 is like +he had in fact + + align:start position:0% +he had in fact + + + align:start position:0% +he had in fact +a brokerage accounts from a national + + align:start position:0% +a brokerage accounts from a national + + + align:start position:0% +a brokerage accounts from a national +weight uh a brokerage house + + align:start position:0% +weight uh a brokerage house + + + align:start position:0% +weight uh a brokerage house +which had all trades and prices for i + + align:start position:0% +which had all trades and prices for i + + + align:start position:0% +which had all trades and prices for i +guess 87 to 93. + + align:start position:0% +guess 87 to 93. + + + align:start position:0% +guess 87 to 93. +in some sense a little bit like + + align:start position:0% +in some sense a little bit like + + + align:start position:0% +in some sense a little bit like +old-fashioned a sense of like you + + align:start position:0% +old-fashioned a sense of like you + + + align:start position:0% +old-fashioned a sense of like you +shouldn't be like in + + align:start position:0% +shouldn't be like in + + + align:start position:0% +shouldn't be like in +individual trading and so on you should + + align:start position:0% +individual trading and so on you should + + + align:start position:0% +individual trading and so on you should +just hold the stock market or the s p + + align:start position:0% +just hold the stock market or the s p + + + align:start position:0% +just hold the stock market or the s p +500 or some index funds and so on + + align:start position:0% +500 or some index funds and so on + + + align:start position:0% +500 or some index funds and so on +here these are people have like hold + + align:start position:0% +here these are people have like hold + + + align:start position:0% +here these are people have like hold +individual stocks and sell and buy them + + align:start position:0% +individual stocks and sell and buy them + + + align:start position:0% +individual stocks and sell and buy them +uh one by one and so during each trading + + align:start position:0% +uh one by one and so during each trading + + + align:start position:0% +uh one by one and so during each trading +day then what our dean can do is he can + + align:start position:0% +day then what our dean can do is he can + + + align:start position:0% +day then what our dean can do is he can +look at + + align:start position:0% +look at + + + align:start position:0% +look at +evaluate each stock in the portfolio and + + align:start position:0% +evaluate each stock in the portfolio and + + + align:start position:0% +evaluate each stock in the portfolio and +look at this as a loss relative to a + + align:start position:0% +look at this as a loss relative to a + + + align:start position:0% +look at this as a loss relative to a +purchase + + align:start position:0% +purchase + + + align:start position:0% +purchase +uh relative to the purchase price so you + + align:start position:0% +uh relative to the purchase price so you + + + align:start position:0% +uh relative to the purchase price so you +can look at essentially + + align:start position:0% +can look at essentially + + + align:start position:0% +can look at essentially +the portfolio and say there's losers and + + align:start position:0% +the portfolio and say there's losers and + + + align:start position:0% +the portfolio and say there's losers and +winners + + align:start position:0% +winners + + + align:start position:0% +winners +he only has like data on trading day so + + align:start position:0% +he only has like data on trading day so + + + align:start position:0% +he only has like data on trading day so +you can look at like you know + + align:start position:0% +you can look at like you know + + + align:start position:0% +you can look at like you know +other losers and uh winners when they're + + align:start position:0% +other losers and uh winners when they're + + + align:start position:0% +other losers and uh winners when they're +being sold + + align:start position:0% +being sold + + + align:start position:0% +being sold +and um he can look at the net realized + + align:start position:0% +and um he can look at the net realized + + + align:start position:0% +and um he can look at the net realized +uh gains and realized losses + + align:start position:0% +uh gains and realized losses + + + align:start position:0% +uh gains and realized losses +so if you sell a stock and it's like + + align:start position:0% +so if you sell a stock and it's like + + + align:start position:0% +so if you sell a stock and it's like +essentially above the purchase price he + + align:start position:0% +essentially above the purchase price he + + + align:start position:0% +essentially above the purchase price he +calls it the realized um + + align:start position:0% +calls it the realized um + + + align:start position:0% +calls it the realized um +uh again loss and if it's um sorry if + + align:start position:0% +uh again loss and if it's um sorry if + + + align:start position:0% +uh again loss and if it's um sorry if +it's + + align:start position:0% +it's + + + align:start position:0% +it's +if it's a losing stock it's old it's a + + align:start position:0% +if it's a losing stock it's old it's a + + + align:start position:0% +if it's a losing stock it's old it's a +realized loss it's below the purchase + + align:start position:0% +realized loss it's below the purchase + + + align:start position:0% +realized loss it's below the purchase +price + + align:start position:0% +price + + + align:start position:0% +price +if it's above the purchase price it's + + align:start position:0% +if it's above the purchase price it's + + + align:start position:0% +if it's above the purchase price it's +going to be a realized gain + + align:start position:0% +going to be a realized gain + + + align:start position:0% +going to be a realized gain +now one thing you could do is like + + align:start position:0% +now one thing you could do is like + + + align:start position:0% +now one thing you could do is like +compare the number of realized losses to + + align:start position:0% +compare the number of realized losses to + + + align:start position:0% +compare the number of realized losses to +the + + align:start position:0% +the + + + align:start position:0% +the +number of realized gains does that work + + align:start position:0% +number of realized gains does that work + + + align:start position:0% +number of realized gains does that work +or is that reference dependence or what + + align:start position:0% +or is that reference dependence or what + + + align:start position:0% +or is that reference dependence or what +do we what do we learn from that + + align:start position:0% + + + + align:start position:0% + +yes + + align:start position:0% + + + + align:start position:0% + +right so i could look at like the + + align:start position:0% +right so i could look at like the + + + align:start position:0% +right so i could look at like the +realized gains and the number of + + align:start position:0% +realized gains and the number of + + + align:start position:0% +realized gains and the number of +realized gains and the number of + + align:start position:0% +realized gains and the number of + + + align:start position:0% +realized gains and the number of +realized losses + + align:start position:0% +realized losses + + + align:start position:0% +realized losses +but what's the problem with that i think + + align:start position:0% +but what's the problem with that i think + + + align:start position:0% +but what's the problem with that i think +that's exactly right but like what's the + + align:start position:0% +that's exactly right but like what's the + + + align:start position:0% +that's exactly right but like what's the +underlying what's the problem with this + + align:start position:0% +underlying what's the problem with this + + + align:start position:0% +underlying what's the problem with this +approach + + align:start position:0% + + + + align:start position:0% + +like how does this depend on the stock + + align:start position:0% +like how does this depend on the stock + + + align:start position:0% +like how does this depend on the stock +market going up and down + + align:start position:0% + + + + align:start position:0% + +yeah so that's a separate issue like you + + align:start position:0% +yeah so that's a separate issue like you + + + align:start position:0% +yeah so that's a separate issue like you +could look at the magnitudes + + align:start position:0% +could look at the magnitudes + + + align:start position:0% +could look at the magnitudes +themselves and you look at sort of like + + align:start position:0% +themselves and you look at sort of like + + + align:start position:0% +themselves and you look at sort of like +depending on where you are + + align:start position:0% +depending on where you are + + + align:start position:0% +depending on where you are +how does that matter but what about just + + align:start position:0% +how does that matter but what about just + + + align:start position:0% +how does that matter but what about just +a number of gains and losses + + align:start position:0% +a number of gains and losses + + + align:start position:0% +a number of gains and losses +like what if the stock market goes up a + + align:start position:0% +like what if the stock market goes up a + + + align:start position:0% +like what if the stock market goes up a +lot what are people going to + + align:start position:0% +lot what are people going to + + + align:start position:0% +lot what are people going to +sell or + + align:start position:0% + + + + align:start position:0% + +right so he does have that i think that + + align:start position:0% +right so he does have that i think that + + + align:start position:0% +right so he does have that i think that +i'm asking for something very + + align:start position:0% +i'm asking for something very + + + align:start position:0% +i'm asking for something very +basic which is if the stock market goes + + align:start position:0% +basic which is if the stock market goes + + + align:start position:0% +basic which is if the stock market goes +up a lot you'll have lots of winners so + + align:start position:0% +up a lot you'll have lots of winners so + + + align:start position:0% +up a lot you'll have lots of winners so +you're going to realize lots of + + align:start position:0% +you're going to realize lots of + + + align:start position:0% +you're going to realize lots of +if you just sell randomly stocks gains + + align:start position:0% +if you just sell randomly stocks gains + + + align:start position:0% +if you just sell randomly stocks gains +and losses and you just don't care + + align:start position:0% +and losses and you just don't care + + + align:start position:0% +and losses and you just don't care +you'll have much more realized gains um + + align:start position:0% +you'll have much more realized gains um + + + align:start position:0% +you'll have much more realized gains um +compared to realized losses just because + + align:start position:0% +compared to realized losses just because + + + align:start position:0% +compared to realized losses just because +your stock market went up a lot + + align:start position:0% +your stock market went up a lot + + + align:start position:0% +your stock market went up a lot +similarly if the stock market went down + + align:start position:0% +similarly if the stock market went down + + + align:start position:0% +similarly if the stock market went down +you will find that people have way more + + align:start position:0% +you will find that people have way more + + + align:start position:0% +you will find that people have way more +realized losses compared to realized + + align:start position:0% +realized losses compared to realized + + + align:start position:0% +realized losses compared to realized +gains and it looked like i'm really + + align:start position:0% +gains and it looked like i'm really + + + align:start position:0% +gains and it looked like i'm really +trying to sell the losers but it's not + + align:start position:0% +trying to sell the losers but it's not + + + align:start position:0% +trying to sell the losers but it's not +i'm actually selling to losers you just + + align:start position:0% +i'm actually selling to losers you just + + + align:start position:0% +i'm actually selling to losers you just +have a lot more + + align:start position:0% +have a lot more + + + align:start position:0% +have a lot more +losers that's all i was asking i think + + align:start position:0% +losers that's all i was asking i think + + + align:start position:0% +losers that's all i was asking i think +he has actually the information about + + align:start position:0% +he has actually the information about + + + align:start position:0% +he has actually the information about +the purchase prices + + align:start position:0% +the purchase prices + + + align:start position:0% +the purchase prices +so what he then does is something very + + align:start position:0% +so what he then does is something very + + + align:start position:0% +so what he then does is something very +simple it just looks at people's + + align:start position:0% +simple it just looks at people's + + + align:start position:0% +simple it just looks at people's +portfolios and says like how many losing + + align:start position:0% +portfolios and says like how many losing + + + align:start position:0% +portfolios and says like how many losing +stocks do you have + + align:start position:0% +stocks do you have + + + align:start position:0% +stocks do you have +what's your propensity to sell the + + align:start position:0% +what's your propensity to sell the + + + align:start position:0% +what's your propensity to sell the +losing stocks which is what he calls the + + align:start position:0% +losing stocks which is what he calls the + + + align:start position:0% +losing stocks which is what he calls the +plr + + align:start position:0% +plr + + + align:start position:0% +plr +the propensity proportion of losers + + align:start position:0% +the propensity proportion of losers + + + align:start position:0% +the propensity proportion of losers +realized the same he does for the pgr + + align:start position:0% +realized the same he does for the pgr + + + align:start position:0% +realized the same he does for the pgr +which is the poor proportion of gains + + align:start position:0% +which is the poor proportion of gains + + + align:start position:0% +which is the poor proportion of gains +realize + + align:start position:0% +realize + + + align:start position:0% +realize +so it looks at each person when they + + align:start position:0% +so it looks at each person when they + + + align:start position:0% +so it looks at each person when they +sell something they look at like how + + align:start position:0% +sell something they look at like how + + + align:start position:0% +sell something they look at like how +many losing stocks you have how many + + align:start position:0% +many losing stocks you have how many + + + align:start position:0% +many losing stocks you have how many +winning stocks you have + + align:start position:0% +winning stocks you have + + + align:start position:0% +winning stocks you have +and then you look at like what's the + + align:start position:0% +and then you look at like what's the + + + align:start position:0% +and then you look at like what's the +probability of you selling + + align:start position:0% +probability of you selling + + + align:start position:0% +probability of you selling +any of those depending on the winners or + + align:start position:0% +any of those depending on the winners or + + + align:start position:0% +any of those depending on the winners or +losers + + align:start position:0% +losers + + + align:start position:0% +losers +so what the main finding then here is + + align:start position:0% +so what the main finding then here is + + + align:start position:0% +so what the main finding then here is +that the pgr the proportion of + + align:start position:0% +that the pgr the proportion of + + + align:start position:0% +that the pgr the proportion of +gains realized is larger than the plr + + align:start position:0% +gains realized is larger than the plr + + + align:start position:0% +gains realized is larger than the plr +that's to say that's called what they + + align:start position:0% +that's to say that's called what they + + + align:start position:0% +that's to say that's called what they +call like the disposition effect + + align:start position:0% +call like the disposition effect + + + align:start position:0% +call like the disposition effect +which is the tendency to sell winners + + align:start position:0% +which is the tendency to sell winners + + + align:start position:0% +which is the tendency to sell winners +and hold on to losers + + align:start position:0% +and hold on to losers + + + align:start position:0% +and hold on to losers +does that make sense okay and so why do + + align:start position:0% +does that make sense okay and so why do + + + align:start position:0% +does that make sense okay and so why do +we care about that or why is this + + align:start position:0% +we care about that or why is this + + + align:start position:0% +we care about that or why is this +actually bad is this it's necessarily + + align:start position:0% +actually bad is this it's necessarily + + + align:start position:0% +actually bad is this it's necessarily +like sub-optimal behavior + + align:start position:0% +like sub-optimal behavior + + + align:start position:0% +like sub-optimal behavior +why do we care + + align:start position:0% + + + + align:start position:0% + +yes + + align:start position:0% +yes + + + align:start position:0% +yes +[Music] + + align:start position:0% + + + + align:start position:0% + +there probably shouldn't be an overall + + align:start position:0% +there probably shouldn't be an overall + + + align:start position:0% +there probably shouldn't be an overall +bias towards + + align:start position:0% +bias towards + + + align:start position:0% +bias towards +like selling like users and that + + align:start position:0% +like selling like users and that + + + align:start position:0% +like selling like users and that +probably isn't like an overall + + align:start position:0% +probably isn't like an overall + + + align:start position:0% +probably isn't like an overall +like effective strategy right so it + + align:start position:0% +like effective strategy right so it + + + align:start position:0% +like effective strategy right so it +depends on essentially how well the + + align:start position:0% +depends on essentially how well the + + + align:start position:0% +depends on essentially how well the +winners and the losers gonna do + + align:start position:0% +winners and the losers gonna do + + + align:start position:0% +winners and the losers gonna do +it turns out so in principle you would + + align:start position:0% +it turns out so in principle you would + + + align:start position:0% +it turns out so in principle you would +say well winners and losers should have + + align:start position:0% +say well winners and losers should have + + + align:start position:0% +say well winners and losers should have +the same + + align:start position:0% +the same + + + align:start position:0% +the same +expected return regardless of their + + align:start position:0% +expected return regardless of their + + + align:start position:0% +expected return regardless of their +winners and losers in the past that's + + align:start position:0% +winners and losers in the past that's + + + align:start position:0% +winners and losers in the past that's +essentially the efficient market + + align:start position:0% +essentially the efficient market + + + align:start position:0% +essentially the efficient market +hypothesis just to say + + align:start position:0% +hypothesis just to say + + + align:start position:0% +hypothesis just to say +past uh price changes should just not be + + align:start position:0% +past uh price changes should just not be + + + align:start position:0% +past uh price changes should just not be +predictive of like future + + align:start position:0% +predictive of like future + + + align:start position:0% +predictive of like future +uh uh momentum or price changes overall + + align:start position:0% +uh uh momentum or price changes overall + + + align:start position:0% +uh uh momentum or price changes overall +because the current price should have + + align:start position:0% +because the current price should have + + + align:start position:0% +because the current price should have +incorporated essentially all information + + align:start position:0% +incorporated essentially all information + + + align:start position:0% +incorporated essentially all information +that's available at this point in time + + align:start position:0% +that's available at this point in time + + + align:start position:0% +that's available at this point in time +so to that degree it shouldn't matter + + align:start position:0% +so to that degree it shouldn't matter + + + align:start position:0% +so to that degree it shouldn't matter +actually what you sell you could just + + align:start position:0% +actually what you sell you could just + + + align:start position:0% +actually what you sell you could just +randomly sell stuff + + align:start position:0% +randomly sell stuff + + + align:start position:0% +randomly sell stuff +now you should not sell a lot usually + + align:start position:0% +now you should not sell a lot usually + + + align:start position:0% +now you should not sell a lot usually +there's commissions involved in these + + align:start position:0% +there's commissions involved in these + + + align:start position:0% +there's commissions involved in these +trades so like essentially you shouldn't + + align:start position:0% +trades so like essentially you shouldn't + + + align:start position:0% +trades so like essentially you shouldn't +sell anything that's essentially leading + + align:start position:0% +sell anything that's essentially leading + + + align:start position:0% +sell anything that's essentially leading +to over trading + + align:start position:0% +to over trading + + + align:start position:0% +to over trading +uh odin has another paper that shows + + align:start position:0% +uh odin has another paper that shows + + + align:start position:0% +uh odin has another paper that shows +essentially in particular men tend to be + + align:start position:0% +essentially in particular men tend to be + + + align:start position:0% +essentially in particular men tend to be +overconfident and and how good they are + + align:start position:0% +overconfident and and how good they are + + + align:start position:0% +overconfident and and how good they are +trading and they tend to over trade and + + align:start position:0% +trading and they tend to over trade and + + + align:start position:0% +trading and they tend to over trade and +that's really costly + + align:start position:0% +that's really costly + + + align:start position:0% +that's really costly +it turns out that like in their specific + + align:start position:0% +it turns out that like in their specific + + + align:start position:0% +it turns out that like in their specific +period + + align:start position:0% +period + + + align:start position:0% +period +um in fact there's momentum and that + + align:start position:0% +um in fact there's momentum and that + + + align:start position:0% +um in fact there's momentum and that +used to be the case + + align:start position:0% +used to be the case + + + align:start position:0% +used to be the case +uh quite a bit in that period of time + + align:start position:0% +uh quite a bit in that period of time + + + align:start position:0% +uh quite a bit in that period of time +which essentially is to do the winners + + align:start position:0% +which essentially is to do the winners + + + align:start position:0% +which essentially is to do the winners +actually doing better than the losers by + + align:start position:0% +actually doing better than the losers by + + + align:start position:0% +actually doing better than the losers by +quite a bit more big margin + + align:start position:0% +quite a bit more big margin + + + align:start position:0% +quite a bit more big margin +that is to say you should have actually + + align:start position:0% +that is to say you should have actually + + + align:start position:0% +that is to say you should have actually +did exactly done the opposite if + + align:start position:0% +did exactly done the opposite if + + + align:start position:0% +did exactly done the opposite if +anything you should have sold the losers + + align:start position:0% +anything you should have sold the losers + + + align:start position:0% +anything you should have sold the losers +and keep on keep the winners because + + align:start position:0% +and keep on keep the winners because + + + align:start position:0% +and keep on keep the winners because +they are + + align:start position:0% +they are + + + align:start position:0% +they are +in fact making more money in the short + + align:start position:0% +in fact making more money in the short + + + align:start position:0% +in fact making more money in the short +and medium run in that period + + align:start position:0% +and medium run in that period + + + align:start position:0% +and medium run in that period +okay um there's also the the investors + + align:start position:0% +okay um there's also the the investors + + + align:start position:0% +okay um there's also the the investors +sell more losers and winners in december + + align:start position:0% +sell more losers and winners in december + + + align:start position:0% +sell more losers and winners in december +um this is what you see here + + align:start position:0% +um this is what you see here + + + align:start position:0% +um this is what you see here +why is that + + align:start position:0% + + + + align:start position:0% + +yes exactly this is for tax reasons so + + align:start position:0% +yes exactly this is for tax reasons so + + + align:start position:0% +yes exactly this is for tax reasons so +that's actually happens to the + + align:start position:0% +that's actually happens to the + + + align:start position:0% +that's actually happens to the +shin portable i was in the economic + + align:start position:0% +shin portable i was in the economic + + + align:start position:0% +shin portable i was in the economic +support and actually if you paper in + + align:start position:0% +support and actually if you paper in + + + align:start position:0% +support and actually if you paper in +this + + align:start position:0% +this + + + align:start position:0% +this +so there you can essentially realize + + align:start position:0% +so there you can essentially realize + + + align:start position:0% +so there you can essentially realize +losses and that that + + align:start position:0% +losses and that that + + + align:start position:0% +losses and that that +reduces your taxes overall um + + align:start position:0% +reduces your taxes overall um + + + align:start position:0% +reduces your taxes overall um +exactly but overall essentially what's + + align:start position:0% +exactly but overall essentially what's + + + align:start position:0% +exactly but overall essentially what's +happening is that people do seem to + + align:start position:0% +happening is that people do seem to + + + align:start position:0% +happening is that people do seem to +engage in this behavior + + align:start position:0% +engage in this behavior + + + align:start position:0% +engage in this behavior +um in a pretty striking fashion they + + align:start position:0% +um in a pretty striking fashion they + + + align:start position:0% +um in a pretty striking fashion they +seem to be losing um + + align:start position:0% +seem to be losing um + + + align:start position:0% +seem to be losing um +quite a bit of money from that + + align:start position:0% +quite a bit of money from that + + + align:start position:0% +quite a bit of money from that +okay let me mention uh at least the + + align:start position:0% +okay let me mention uh at least the + + + align:start position:0% +okay let me mention uh at least the +marathon running and perhaps the golf + + align:start position:0% +marathon running and perhaps the golf + + + align:start position:0% +marathon running and perhaps the golf +example and then we're going to move + + align:start position:0% +example and then we're going to move + + + align:start position:0% +example and then we're going to move +towards like + + align:start position:0% +towards like + + + align:start position:0% +towards like +uh prices and firms how do firms react + + align:start position:0% +uh prices and firms how do firms react + + + align:start position:0% +uh prices and firms how do firms react +to these biases + + align:start position:0% +to these biases + + + align:start position:0% +to these biases +but what i'm trying to do here is + + align:start position:0% +but what i'm trying to do here is + + + align:start position:0% +but what i'm trying to do here is +essentially show you a bunch of + + align:start position:0% +essentially show you a bunch of + + + align:start position:0% +essentially show you a bunch of +different settings and essentially if + + align:start position:0% +different settings and essentially if + + + align:start position:0% +different settings and essentially if +you look at different settings in the + + align:start position:0% +you look at different settings in the + + + align:start position:0% +you look at different settings in the +world + + align:start position:0% +world + + + align:start position:0% +world +there's lots and lots of different + + align:start position:0% +there's lots and lots of different + + + align:start position:0% +there's lots and lots of different +settings where reference dependence + + align:start position:0% +settings where reference dependence + + + align:start position:0% +settings where reference dependence +seems to matter one way or the other + + align:start position:0% +seems to matter one way or the other + + + align:start position:0% +seems to matter one way or the other +seems to be important in shaping + + align:start position:0% +seems to be important in shaping + + + align:start position:0% +seems to be important in shaping +people's behavior + + align:start position:0% +people's behavior + + + align:start position:0% +people's behavior +so um this is a very nice paper about + + align:start position:0% +so um this is a very nice paper about + + + align:start position:0% +so um this is a very nice paper about +marathon running + + align:start position:0% +marathon running + + + align:start position:0% +marathon running +finishing times these are many many + + align:start position:0% +finishing times these are many many + + + align:start position:0% +finishing times these are many many +marathons they have lots of data on + + align:start position:0% +marathons they have lots of data on + + + align:start position:0% +marathons they have lots of data on +finishing times for people + + align:start position:0% +finishing times for people + + + align:start position:0% +finishing times for people +so the lot of large numbers would + + align:start position:0% +so the lot of large numbers would + + + align:start position:0% +so the lot of large numbers would +predict that if you look at essentially + + align:start position:0% +predict that if you look at essentially + + + align:start position:0% +predict that if you look at essentially +people's finishing times + + align:start position:0% +people's finishing times + + + align:start position:0% +people's finishing times +if people have different talents and so + + align:start position:0% +if people have different talents and so + + + align:start position:0% +if people have different talents and so +on and so forth the finishing times + + align:start position:0% +on and so forth the finishing times + + + align:start position:0% +on and so forth the finishing times +should look something like this + + align:start position:0% +should look something like this + + + align:start position:0% +should look something like this +okay there's some people are faster some + + align:start position:0% +okay there's some people are faster some + + + align:start position:0% +okay there's some people are faster some +people are slower but overall there + + align:start position:0% +people are slower but overall there + + + align:start position:0% +people are slower but overall there +should be some + + align:start position:0% +should be some + + + align:start position:0% +should be some +um uh smooth distribution that + + align:start position:0% +um uh smooth distribution that + + + align:start position:0% +um uh smooth distribution that +essentially is like log normal or + + align:start position:0% +essentially is like log normal or + + + align:start position:0% +essentially is like log normal or +whatever you want it to be but + + align:start position:0% +whatever you want it to be but + + + align:start position:0% +whatever you want it to be but +essentially it should look something + + align:start position:0% +essentially it should look something + + + align:start position:0% +essentially it should look something +like this + + align:start position:0% +like this + + + align:start position:0% +like this +so my why might it not look like this or + + align:start position:0% +so my why might it not look like this or + + + align:start position:0% +so my why might it not look like this or +what's what what might people do instead + + align:start position:0% + + + + align:start position:0% + +yes they may say i'll be 4 30 and then + + align:start position:0% +yes they may say i'll be 4 30 and then + + + align:start position:0% +yes they may say i'll be 4 30 and then +you might see bunching + + align:start position:0% +you might see bunching + + + align:start position:0% +you might see bunching +at certain points like four hours four + + align:start position:0% +at certain points like four hours four + + + align:start position:0% +at certain points like four hours four +thirty five hours five thursday + + align:start position:0% +thirty five hours five thursday + + + align:start position:0% +thirty five hours five thursday +right so exactly as you say it might be + + align:start position:0% +right so exactly as you say it might be + + + align:start position:0% +right so exactly as you say it might be +that people have reference points + + align:start position:0% +that people have reference points + + + align:start position:0% +that people have reference points +not in terms of like status quo here and + + align:start position:0% +not in terms of like status quo here and + + + align:start position:0% +not in terms of like status quo here and +the like reference points might be goals + + align:start position:0% +the like reference points might be goals + + + align:start position:0% +the like reference points might be goals +or aspirations you might say i really + + align:start position:0% +or aspirations you might say i really + + + align:start position:0% +or aspirations you might say i really +want to run the marathon in four hours + + align:start position:0% +want to run the marathon in four hours + + + align:start position:0% +want to run the marathon in four hours +or for 30 or + + align:start position:0% +or for 30 or + + + align:start position:0% +or for 30 or +five hours if you want and then um what + + align:start position:0% +five hours if you want and then um what + + + align:start position:0% +five hours if you want and then um what +the marathon times actually look like is + + align:start position:0% +the marathon times actually look like is + + + align:start position:0% +the marathon times actually look like is +something like this + + align:start position:0% +something like this + + + align:start position:0% +something like this +and in particular it seems like people + + align:start position:0% +and in particular it seems like people + + + align:start position:0% +and in particular it seems like people +have lots of goals of reaching something + + align:start position:0% +have lots of goals of reaching something + + + align:start position:0% +have lots of goals of reaching something +like um and + + align:start position:0% +like um and + + + align:start position:0% +like um and +you know as you if you look at this + + align:start position:0% +you know as you if you look at this + + + align:start position:0% +you know as you if you look at this +distribution what you see is exactly as + + align:start position:0% +distribution what you see is exactly as + + + align:start position:0% +distribution what you see is exactly as +you predict + + align:start position:0% +you predict + + + align:start position:0% +you predict +um uh if you look at the half hour or + + align:start position:0% +um uh if you look at the half hour or + + + align:start position:0% +um uh if you look at the half hour or +the + + align:start position:0% +the + + + align:start position:0% +the +even the quarter hour sort of points + + align:start position:0% +even the quarter hour sort of points + + + align:start position:0% +even the quarter hour sort of points +there's essentially bunching from below + + align:start position:0% +there's essentially bunching from below + + + align:start position:0% +there's essentially bunching from below +so essentially people seem to be + + align:start position:0% +so essentially people seem to be + + + align:start position:0% +so essentially people seem to be +if they're like at pace or finish at + + align:start position:0% +if they're like at pace or finish at + + + align:start position:0% +if they're like at pace or finish at +four + + align:start position:0% +four + + + align:start position:0% +four +hours in one minute they try to sort of + + align:start position:0% +hours in one minute they try to sort of + + + align:start position:0% +hours in one minute they try to sort of +speed up and just make it to like three + + align:start position:0% +speed up and just make it to like three + + + align:start position:0% +speed up and just make it to like three +um 59 and so + + align:start position:0% +um 59 and so + + + align:start position:0% +um 59 and so +you even so you see a bunch of bunching + + align:start position:0% +you even so you see a bunch of bunching + + + align:start position:0% +you even so you see a bunch of bunching +um at the half hour slots + + align:start position:0% +um at the half hour slots + + + align:start position:0% +um at the half hour slots +you see actually much less at like six + + align:start position:0% +you see actually much less at like six + + + align:start position:0% +you see actually much less at like six +hours and 30 minutes or something seemed + + align:start position:0% +hours and 30 minutes or something seemed + + + align:start position:0% +hours and 30 minutes or something seemed +to like few people have actually goals + + align:start position:0% +to like few people have actually goals + + + align:start position:0% +to like few people have actually goals +once you've + + align:start position:0% +once you've + + + align:start position:0% +once you've +like run the marathon in six hours and + + align:start position:0% +like run the marathon in six hours and + + + align:start position:0% +like run the marathon in six hours and +30 minutes which is probably what i + + align:start position:0% +30 minutes which is probably what i + + + align:start position:0% +30 minutes which is probably what i +would do + + align:start position:0% +would do + + + align:start position:0% +would do +you know it doesn't really matter + + align:start position:0% +you know it doesn't really matter + + + align:start position:0% +you know it doesn't really matter +whether you like 6 31 or 6 29 + + align:start position:0% +whether you like 6 31 or 6 29 + + + align:start position:0% +whether you like 6 31 or 6 29 +uh but there's very ambitious people who + + align:start position:0% +uh but there's very ambitious people who + + + align:start position:0% +uh but there's very ambitious people who +want to like finish in like 4 30 + + align:start position:0% +want to like finish in like 4 30 + + + align:start position:0% +want to like finish in like 4 30 +4 hours or 3 30 and the like and there's + + align:start position:0% +4 hours or 3 30 and the like and there's + + + align:start position:0% +4 hours or 3 30 and the like and there's +a bunch of um + + align:start position:0% +a bunch of um + + + align:start position:0% +a bunch of um +bunching from below there so you see the + + align:start position:0% +bunching from below there so you see the + + + align:start position:0% +bunching from below there so you see the +same for like + + align:start position:0% +same for like + + + align:start position:0% +same for like +a quarter hour times a little bit less + + align:start position:0% +a quarter hour times a little bit less + + + align:start position:0% +a quarter hour times a little bit less +of that + + align:start position:0% +of that + + + align:start position:0% +of that +um and sort of that's consistent with + + align:start position:0% +um and sort of that's consistent with + + + align:start position:0% +um and sort of that's consistent with +the reference point here being like + + align:start position:0% +the reference point here being like + + + align:start position:0% +the reference point here being like +a goal and aspiration you want to reach + + align:start position:0% +a goal and aspiration you want to reach + + + align:start position:0% +a goal and aspiration you want to reach +four minutes you want to brag to your + + align:start position:0% +four minutes you want to brag to your + + + align:start position:0% +four minutes you want to brag to your +friends and so on and it's not so great + + align:start position:0% +friends and so on and it's not so great + + + align:start position:0% +friends and so on and it's not so great +if you do that and say i + + align:start position:0% +if you do that and say i + + + align:start position:0% +if you do that and say i +finished in four hours in one minute as + + align:start position:0% +finished in four hours in one minute as + + + align:start position:0% +finished in four hours in one minute as +opposed to if you say i finish below + + align:start position:0% +opposed to if you say i finish below + + + align:start position:0% +opposed to if you say i finish below +four hours now when you look at the + + align:start position:0% +four hours now when you look at the + + + align:start position:0% +four hours now when you look at the +effort at the + + align:start position:0% +effort at the + + + align:start position:0% +effort at the +end of the race what is it what would + + align:start position:0% +end of the race what is it what would + + + align:start position:0% +end of the race what is it what would +you expect so what we have here on the + + align:start position:0% +you expect so what we have here on the + + + align:start position:0% +you expect so what we have here on the +x-axis + + align:start position:0% +x-axis + + + align:start position:0% +x-axis +is people these are like the uh 40 + + align:start position:0% +is people these are like the uh 40 + + + align:start position:0% +is people these are like the uh 40 +kilometer pace these are like in 30 + + align:start position:0% +kilometer pace these are like in 30 + + + align:start position:0% +kilometer pace these are like in 30 +second increments this is kind of like + + align:start position:0% +second increments this is kind of like + + + align:start position:0% +second increments this is kind of like +during the so the marathon is 40 um + + align:start position:0% +during the so the marathon is 40 um + + + align:start position:0% +during the so the marathon is 40 um +uh uh 42.195 kilometers + + align:start position:0% +uh uh 42.195 kilometers + + + align:start position:0% +uh uh 42.195 kilometers +um so what i'm showing you here is like + + align:start position:0% +um so what i'm showing you here is like + + + align:start position:0% +um so what i'm showing you here is like +essentially people the 40 kilometer pace + + align:start position:0% +essentially people the 40 kilometer pace + + + align:start position:0% +essentially people the 40 kilometer pace +people + + align:start position:0% +people + + + align:start position:0% +people +are ranked by the 40 are distributed by + + align:start position:0% +are ranked by the 40 are distributed by + + + align:start position:0% +are ranked by the 40 are distributed by +the 40 kilometer pace + + align:start position:0% +the 40 kilometer pace + + + align:start position:0% +the 40 kilometer pace +uh the first 40 kilometers now what you + + align:start position:0% +uh the first 40 kilometers now what you + + + align:start position:0% +uh the first 40 kilometers now what you +would you expect for people so there's + + align:start position:0% +would you expect for people so there's + + + align:start position:0% +would you expect for people so there's +some people who + + align:start position:0% +some people who + + + align:start position:0% +some people who +like were at pace for like to reach um + + align:start position:0% +like were at pace for like to reach um + + + align:start position:0% +like were at pace for like to reach um + + align:start position:0% + + + align:start position:0% +and some people at pace to reach four or + + align:start position:0% +and some people at pace to reach four or + + + align:start position:0% +and some people at pace to reach four or +five and so on what is it that you would + + align:start position:0% +five and so on what is it that you would + + + align:start position:0% +five and so on what is it that you would +expect people to do when you look at + + align:start position:0% +expect people to do when you look at + + + align:start position:0% +expect people to do when you look at +like how fast people run + + align:start position:0% +like how fast people run + + + align:start position:0% +like how fast people run +uh towards the end the last two + + align:start position:0% +uh towards the end the last two + + + align:start position:0% +uh towards the end the last two +kilometers of the race + + align:start position:0% + + + + align:start position:0% + +yes + + align:start position:0% + + + + align:start position:0% + +exactly and this is what you see so low + + align:start position:0% +exactly and this is what you see so low + + + align:start position:0% +exactly and this is what you see so low +means like you're running fast + + align:start position:0% +means like you're running fast + + + align:start position:0% +means like you're running fast +so this is like uh minutes per kilometer + + align:start position:0% +so this is like uh minutes per kilometer + + + align:start position:0% +so this is like uh minutes per kilometer +i think + + align:start position:0% +i think + + + align:start position:0% +i think +or relative minutes per kilometers so + + align:start position:0% +or relative minutes per kilometers so + + + align:start position:0% +or relative minutes per kilometers so +what you should expect is like people + + align:start position:0% +what you should expect is like people + + + align:start position:0% +what you should expect is like people +who are + + align:start position:0% +who are + + + align:start position:0% +who are +just below the goal or people who are + + align:start position:0% +just below the goal or people who are + + + align:start position:0% +just below the goal or people who are +essentially just above the goal in fact + + align:start position:0% +essentially just above the goal in fact + + + align:start position:0% +essentially just above the goal in fact +these are the people who speed up okay + + align:start position:0% +these are the people who speed up okay + + + align:start position:0% +these are the people who speed up okay +so + + align:start position:0% +so + + + align:start position:0% +so +um and this is exactly what you sort of + + align:start position:0% +um and this is exactly what you sort of + + + align:start position:0% +um and this is exactly what you sort of +see is the people who are + + align:start position:0% +see is the people who are + + + align:start position:0% +see is the people who are +just below the four or four minute mark + + align:start position:0% +just below the four or four minute mark + + + align:start position:0% +just below the four or four minute mark +or some people who are like just above + + align:start position:0% +or some people who are like just above + + + align:start position:0% +or some people who are like just above +they speed up to just make it uh to that + + align:start position:0% +they speed up to just make it uh to that + + + align:start position:0% +they speed up to just make it uh to that +goal and sort of um + + align:start position:0% +goal and sort of um + + + align:start position:0% +goal and sort of um +allen and i'll have like a sort of + + align:start position:0% +allen and i'll have like a sort of + + + align:start position:0% +allen and i'll have like a sort of +analysis of this essentially what they + + align:start position:0% +analysis of this essentially what they + + + align:start position:0% +analysis of this essentially what they +find is that + + align:start position:0% +find is that + + + align:start position:0% +find is that +um everybody gets sort of slower towards + + align:start position:0% +um everybody gets sort of slower towards + + + align:start position:0% +um everybody gets sort of slower towards +the end of the race but if you're sort + + align:start position:0% +the end of the race but if you're sort + + + align:start position:0% +the end of the race but if you're sort +of in reach of of reaching the goal by + + align:start position:0% +of in reach of of reaching the goal by + + + align:start position:0% +of in reach of of reaching the goal by +form + + align:start position:0% +form + + + align:start position:0% +form +for uh the reaching the time of four + + align:start position:0% +for uh the reaching the time of four + + + align:start position:0% +for uh the reaching the time of four +hours you're gonna + + align:start position:0% +hours you're gonna + + + align:start position:0% +hours you're gonna +uh slow down less so speed up a bit to + + align:start position:0% +uh slow down less so speed up a bit to + + + align:start position:0% +uh slow down less so speed up a bit to +just reach that + + align:start position:0% +just reach that + + + align:start position:0% +just reach that +uh a specific goal okay + + align:start position:0% +uh a specific goal okay + + + align:start position:0% +uh a specific goal okay +uh let me show you one more thing of + + align:start position:0% +uh let me show you one more thing of + + + align:start position:0% +uh let me show you one more thing of +sports which is like a + + align:start position:0% +sports which is like a + + + align:start position:0% +sports which is like a +a golf so how does golf work in case you + + align:start position:0% +a golf so how does golf work in case you + + + align:start position:0% +a golf so how does golf work in case you +don't know um + + align:start position:0% +don't know um + + + align:start position:0% +don't know um +you you hit a ball um with a club from a + + align:start position:0% +you you hit a ball um with a club from a + + + align:start position:0% +you you hit a ball um with a club from a +tee into like a hole + + align:start position:0% +tee into like a hole + + + align:start position:0% +tee into like a hole +um the way this works is um there's + + align:start position:0% +um the way this works is um there's + + + align:start position:0% +um the way this works is um there's +usually uh four rounds of 18 holes + + align:start position:0% +usually uh four rounds of 18 holes + + + align:start position:0% +usually uh four rounds of 18 holes +um this is there's very convex + + align:start position:0% +um this is there's very convex + + + align:start position:0% +um this is there's very convex +incentives + + align:start position:0% +incentives + + + align:start position:0% +incentives +in the golf tournaments so you get a + + align:start position:0% +in the golf tournaments so you get a + + + align:start position:0% +in the golf tournaments so you get a +bunch of money if you win if you're sort + + align:start position:0% +bunch of money if you win if you're sort + + + align:start position:0% +bunch of money if you win if you're sort +of at the top + + align:start position:0% +of at the top + + + align:start position:0% +of at the top +for an average performance essentially + + align:start position:0% +for an average performance essentially + + + align:start position:0% +for an average performance essentially +you don't make that much money i mean + + align:start position:0% +you don't make that much money i mean + + + align:start position:0% +you don't make that much money i mean +you make + + align:start position:0% +you make + + + align:start position:0% +you make +good money but you know the the the + + align:start position:0% +good money but you know the the the + + + align:start position:0% +good money but you know the the the +prize the money is really in terms of + + align:start position:0% +prize the money is really in terms of + + + align:start position:0% +prize the money is really in terms of +like + + align:start position:0% +like + + + align:start position:0% +like +uh when you do really well so now what + + align:start position:0% +uh when you do really well so now what + + + align:start position:0% +uh when you do really well so now what +is par + + align:start position:0% +is par + + + align:start position:0% +is par +par is like how many um strokes how many + + align:start position:0% +par is like how many um strokes how many + + + align:start position:0% +par is like how many um strokes how many +shots do you need to + + align:start position:0% +shots do you need to + + + align:start position:0% +shots do you need to +um how many shots a very good golfer + + align:start position:0% +um how many shots a very good golfer + + + align:start position:0% +um how many shots a very good golfer +should require to complete a given + + align:start position:0% +should require to complete a given + + + align:start position:0% +should require to complete a given +a hole so um so par is usually four + + align:start position:0% +a hole so um so par is usually four + + + align:start position:0% +a hole so um so par is usually four +three four or five um shots uh and then + + align:start position:0% +three four or five um shots uh and then + + + align:start position:0% +three four or five um shots uh and then +eagle is like two below par + + align:start position:0% +eagle is like two below par + + + align:start position:0% +eagle is like two below par +so if like you have a par four hole if + + align:start position:0% +so if like you have a par four hole if + + + align:start position:0% +so if like you have a par four hole if +you do two shots that's an eagle + + align:start position:0% +you do two shots that's an eagle + + + align:start position:0% +you do two shots that's an eagle +if you do three shots in that case that + + align:start position:0% +if you do three shots in that case that + + + align:start position:0% +if you do three shots in that case that +would be a birdie four would be par + + align:start position:0% +would be a birdie four would be par + + + align:start position:0% +would be a birdie four would be par +borgie would be one above par and double + + align:start position:0% +borgie would be one above par and double + + + align:start position:0% +borgie would be one above par and double +bogey would be + + align:start position:0% +bogey would be + + + align:start position:0% +bogey would be +uh two above par okay so knowing all + + align:start position:0% +uh two above par okay so knowing all + + + align:start position:0% +uh two above par okay so knowing all +that + + align:start position:0% +that + + + align:start position:0% +that +and so what ends at the what matters for + + align:start position:0% +and so what ends at the what matters for + + + align:start position:0% +and so what ends at the what matters for +golf at the end of a tournament is like + + align:start position:0% +golf at the end of a tournament is like + + + align:start position:0% +golf at the end of a tournament is like +how many shots do you make in total so + + align:start position:0% +how many shots do you make in total so + + + align:start position:0% +how many shots do you make in total so +how can we now look at reference + + align:start position:0% +how can we now look at reference + + + align:start position:0% +how can we now look at reference +dependent preferences here + + align:start position:0% +dependent preferences here + + + align:start position:0% +dependent preferences here +in this setting + + align:start position:0% + + + + align:start position:0% + +yes + + align:start position:0% + + + + align:start position:0% + +yes the reference is the par now suppose + + align:start position:0% +yes the reference is the par now suppose + + + align:start position:0% +yes the reference is the par now suppose +you are + + align:start position:0% +you are + + + align:start position:0% +you are +putting which is at the end you know on + + align:start position:0% +putting which is at the end you know on + + + align:start position:0% +putting which is at the end you know on +the green uh what are you going to do + + align:start position:0% +the green uh what are you going to do + + + align:start position:0% +the green uh what are you going to do +what kinds of behaviors do you expect + + align:start position:0% + + + + align:start position:0% + +yes um well it depends so if you are + + align:start position:0% +yes um well it depends so if you are + + + align:start position:0% +yes um well it depends so if you are +under par + + align:start position:0% +under par + + + align:start position:0% +under par +then you might try like you're shooting + + align:start position:0% +then you might try like you're shooting + + + align:start position:0% +then you might try like you're shooting +for birdie or you're shooting for a car + + align:start position:0% +for birdie or you're shooting for a car + + + align:start position:0% +for birdie or you're shooting for a car +and it's a long cut + + align:start position:0% +and it's a long cut + + + align:start position:0% +and it's a long cut +you might try to make sure that you get + + align:start position:0% +you might try to make sure that you get + + + align:start position:0% +you might try to make sure that you get +into the hole whereas if you're already + + align:start position:0% +into the hole whereas if you're already + + + align:start position:0% +into the hole whereas if you're already +over + + align:start position:0% +over + + + align:start position:0% +over +over par or double over car you might + + align:start position:0% +over par or double over car you might + + + align:start position:0% +over par or double over car you might +try to play a little safer to make sure + + align:start position:0% +try to play a little safer to make sure + + + align:start position:0% +try to play a little safer to make sure +you're not + + align:start position:0% +you're not + + + align:start position:0% +you're not +way over it right so some of this is + + align:start position:0% +way over it right so some of this is + + + align:start position:0% +way over it right so some of this is +about like risk preference is how + + align:start position:0% +about like risk preference is how + + + align:start position:0% +about like risk preference is how +risky your shots are you can another way + + align:start position:0% +risky your shots are you can another way + + + align:start position:0% +risky your shots are you can another way +to think about this is kind of like how + + align:start position:0% +to think about this is kind of like how + + + align:start position:0% +to think about this is kind of like how +much effort do you put in your shot in + + align:start position:0% +much effort do you put in your shot in + + + align:start position:0% +much effort do you put in your shot in +some sense you to the extent that like + + align:start position:0% +some sense you to the extent that like + + + align:start position:0% +some sense you to the extent that like +you can put in + + align:start position:0% +you can put in + + + align:start position:0% +you can put in +you can sort of allocate attention or + + align:start position:0% +you can sort of allocate attention or + + + align:start position:0% +you can sort of allocate attention or +really focus an effort + + align:start position:0% +really focus an effort + + + align:start position:0% +really focus an effort +maybe that's sort of limited over the + + align:start position:0% +maybe that's sort of limited over the + + + align:start position:0% +maybe that's sort of limited over the +course of like 18 holes and four + + align:start position:0% +course of like 18 holes and four + + + align:start position:0% +course of like 18 holes and four +uh uh four rounds uh of each of those + + align:start position:0% +uh uh four rounds uh of each of those + + + align:start position:0% +uh uh four rounds uh of each of those +you know you might sort of put in might + + align:start position:0% +you know you might sort of put in might + + + align:start position:0% +you know you might sort of put in might +try particularly hard to do well on + + align:start position:0% +try particularly hard to do well on + + + align:start position:0% +try particularly hard to do well on +shots that make you + + align:start position:0% +shots that make you + + + align:start position:0% +shots that make you +reach par compared to shots that might + + align:start position:0% +reach par compared to shots that might + + + align:start position:0% +reach par compared to shots that might +get you like a birdie or + + align:start position:0% +get you like a birdie or + + + align:start position:0% +get you like a birdie or +or even better and so this is exactly as + + align:start position:0% +or even better and so this is exactly as + + + align:start position:0% +or even better and so this is exactly as +you say + + align:start position:0% +you say + + + align:start position:0% +you say +the fairly obvious reference point for + + align:start position:0% +the fairly obvious reference point for + + + align:start position:0% +the fairly obvious reference point for +each hole in golf is reached par + + align:start position:0% +each hole in golf is reached par + + + align:start position:0% +each hole in golf is reached par +importantly it doesn't matter um uh + + align:start position:0% +importantly it doesn't matter um uh + + + align:start position:0% +importantly it doesn't matter um uh +whether you have birdie + + align:start position:0% +whether you have birdie + + + align:start position:0% +whether you have birdie +par and bogie versus par par and par + + align:start position:0% +par and bogie versus par par and par + + + align:start position:0% +par and bogie versus par par and par +essentially that gives you exactly the + + align:start position:0% +essentially that gives you exactly the + + + align:start position:0% +essentially that gives you exactly the +same + + align:start position:0% +same + + + align:start position:0% +same +amount of shots overall but um + + align:start position:0% +amount of shots overall but um + + + align:start position:0% +amount of shots overall but um +not what pope and schweitzer ask is the + + align:start position:0% +not what pope and schweitzer ask is the + + + align:start position:0% +not what pope and schweitzer ask is the +question like + + align:start position:0% +question like + + + align:start position:0% +question like +putters um more likely to to make their + + align:start position:0% +putters um more likely to to make their + + + align:start position:0% +putters um more likely to to make their +par + + align:start position:0% +par + + + align:start position:0% +par +uh than their birdie parts right so + + align:start position:0% +uh than their birdie parts right so + + + align:start position:0% +uh than their birdie parts right so +essentially uh depending on like + + align:start position:0% +essentially uh depending on like + + + align:start position:0% +essentially uh depending on like +are you at possibility at losing or like + + align:start position:0% +are you at possibility at losing or like + + + align:start position:0% +are you at possibility at losing or like +at gaining uh + + align:start position:0% +at gaining uh + + + align:start position:0% +at gaining uh +to you essentially if you're worried + + align:start position:0% +to you essentially if you're worried + + + align:start position:0% +to you essentially if you're worried +about like losing par + + align:start position:0% +about like losing par + + + align:start position:0% +about like losing par +are you gonna behave differently + + align:start position:0% +are you gonna behave differently + + + align:start position:0% +are you gonna behave differently +compared to like when you can make a + + align:start position:0% +compared to like when you can make a + + + align:start position:0% +compared to like when you can make a +birdie which is in the game domain + + align:start position:0% +birdie which is in the game domain + + + align:start position:0% +birdie which is in the game domain +potentially + + align:start position:0% +potentially + + + align:start position:0% +potentially +the same you could say about bogeys + + align:start position:0% +the same you could say about bogeys + + + align:start position:0% +the same you could say about bogeys +where like you're already in the loss of + + align:start position:0% +where like you're already in the loss of + + + align:start position:0% +where like you're already in the loss of +men because you're already doing + + align:start position:0% +men because you're already doing + + + align:start position:0% +men because you're already doing +terribly and you're + + align:start position:0% +terribly and you're + + + align:start position:0% +terribly and you're +trying to avoid like a double um vogue + + align:start position:0% +trying to avoid like a double um vogue + + + align:start position:0% +trying to avoid like a double um vogue +so now what they find essentially is + + align:start position:0% +so now what they find essentially is + + + align:start position:0% +so now what they find essentially is +their power puts a much more + + align:start position:0% +their power puts a much more + + + align:start position:0% +their power puts a much more +likely uh to be made there's like two + + align:start position:0% +likely uh to be made there's like two + + + align:start position:0% +likely uh to be made there's like two +three percentage points more likely to + + align:start position:0% +three percentage points more likely to + + + align:start position:0% +three percentage points more likely to +be made compared to equivalent birdie + + align:start position:0% +be made compared to equivalent birdie + + + align:start position:0% +be made compared to equivalent birdie +puts + + align:start position:0% +puts + + + align:start position:0% +puts +the authors rule out a bunch of + + align:start position:0% +the authors rule out a bunch of + + + align:start position:0% +the authors rule out a bunch of +different explanations it doesn't have + + align:start position:0% +different explanations it doesn't have + + + align:start position:0% +different explanations it doesn't have +to do with like heterogeneity + + align:start position:0% +to do with like heterogeneity + + + align:start position:0% +to do with like heterogeneity +player ability they even have sort of + + align:start position:0% +player ability they even have sort of + + + align:start position:0% +player ability they even have sort of +like gps information of exactly where + + align:start position:0% +like gps information of exactly where + + + align:start position:0% +like gps information of exactly where +the ball is compared to the whole and + + align:start position:0% +the ball is compared to the whole and + + + align:start position:0% +the ball is compared to the whole and +they do all sorts of comparison of how + + align:start position:0% +they do all sorts of comparison of how + + + align:start position:0% +they do all sorts of comparison of how +hard the shot is + + align:start position:0% +hard the shot is + + + align:start position:0% +hard the shot is +they don't think it has to do with + + align:start position:0% +they don't think it has to do with + + + align:start position:0% +they don't think it has to do with +learning from earlier puts and it seems + + align:start position:0% +learning from earlier puts and it seems + + + align:start position:0% +learning from earlier puts and it seems +to also not have to do with like whole + + align:start position:0% +to also not have to do with like whole + + + align:start position:0% +to also not have to do with like whole +specific preferences some holes are + + align:start position:0% +specific preferences some holes are + + + align:start position:0% +specific preferences some holes are +really hard and some poles are really + + align:start position:0% +really hard and some poles are really + + + align:start position:0% +really hard and some poles are really +simple and easy and so on so it doesn't + + align:start position:0% +simple and easy and so on so it doesn't + + + align:start position:0% +simple and easy and so on so it doesn't +seem to be uh + + align:start position:0% +seem to be uh + + + align:start position:0% +seem to be uh +to do with any of that so again that's + + align:start position:0% +to do with any of that so again that's + + + align:start position:0% +to do with any of that so again that's +sort of another + + align:start position:0% +sort of another + + + align:start position:0% +sort of another +instance of like reference dependent + + align:start position:0% +instance of like reference dependent + + + align:start position:0% +instance of like reference dependent +that seems to be in quite a few + + align:start position:0% +that seems to be in quite a few + + + align:start position:0% +that seems to be in quite a few +settings let me sort of skip the deal + + align:start position:0% +settings let me sort of skip the deal + + + align:start position:0% +settings let me sort of skip the deal +and no deal tv show which we can + + align:start position:0% +and no deal tv show which we can + + + align:start position:0% +and no deal tv show which we can +do briefly in recitation and talk a + + align:start position:0% +do briefly in recitation and talk a + + + align:start position:0% +do briefly in recitation and talk a +little bit about prices + + align:start position:0% +little bit about prices + + + align:start position:0% +little bit about prices +and firms + + align:start position:0% +and firms + + + align:start position:0% +and firms +so one fact is that we see in the world + + align:start position:0% +so one fact is that we see in the world + + + align:start position:0% +so one fact is that we see in the world +is that + + align:start position:0% +is that + + + align:start position:0% +is that +demand often responds more strongly to + + align:start position:0% +demand often responds more strongly to + + + align:start position:0% +demand often responds more strongly to +price increases than to price decreases + + align:start position:0% +price increases than to price decreases + + + align:start position:0% +price increases than to price decreases +of frequently purchased items and we we + + align:start position:0% +of frequently purchased items and we we + + + align:start position:0% +of frequently purchased items and we we +already discussed that last time is to + + align:start position:0% +already discussed that last time is to + + + align:start position:0% +already discussed that last time is to +say + + align:start position:0% +say + + + align:start position:0% +say +um so usually people have a reference + + align:start position:0% +um so usually people have a reference + + + align:start position:0% +um so usually people have a reference +point in terms of like either the price + + align:start position:0% +point in terms of like either the price + + + align:start position:0% +point in terms of like either the price +they pay or the expenditures on certain + + align:start position:0% +they pay or the expenditures on certain + + + align:start position:0% +they pay or the expenditures on certain +items + + align:start position:0% +items + + + align:start position:0% +items +so now something becomes more expensive + + align:start position:0% +so now something becomes more expensive + + + align:start position:0% +so now something becomes more expensive +what they tend to do is they essentially + + align:start position:0% +what they tend to do is they essentially + + + align:start position:0% +what they tend to do is they essentially +reduce how much they + + align:start position:0% +reduce how much they + + + align:start position:0% +reduce how much they +for example gasoline or the like they + + align:start position:0% +for example gasoline or the like they + + + align:start position:0% +for example gasoline or the like they +tend to then sort of just reduce + + align:start position:0% +tend to then sort of just reduce + + + align:start position:0% +tend to then sort of just reduce +uh uh their expenditures because they + + align:start position:0% +uh uh their expenditures because they + + + align:start position:0% +uh uh their expenditures because they +have like a budget for + + align:start position:0% +have like a budget for + + + align:start position:0% +have like a budget for +say gasoline or certain items and so + + align:start position:0% +say gasoline or certain items and so + + + align:start position:0% +say gasoline or certain items and so +what they tend to do is then the + + align:start position:0% +what they tend to do is then the + + + align:start position:0% +what they tend to do is then the +reference point is either the past price + + align:start position:0% +reference point is either the past price + + + align:start position:0% +reference point is either the past price +or the past expenditures + + align:start position:0% +or the past expenditures + + + align:start position:0% +or the past expenditures +and uh uh people tend to sort of be lost + + align:start position:0% +and uh uh people tend to sort of be lost + + + align:start position:0% +and uh uh people tend to sort of be lost +a verse than over + + align:start position:0% +a verse than over + + + align:start position:0% +a verse than over +uh other certain um their uh + + align:start position:0% +uh other certain um their uh + + + align:start position:0% +uh other certain um their uh +expenditures + + align:start position:0% +expenditures + + + align:start position:0% +expenditures +over the specific uh uh domain + + align:start position:0% +over the specific uh uh domain + + + align:start position:0% +over the specific uh uh domain +now that then leads to so if a firm + + align:start position:0% +now that then leads to so if a firm + + + align:start position:0% +now that then leads to so if a firm +knows this so essentially if you know + + align:start position:0% +knows this so essentially if you know + + + align:start position:0% +knows this so essentially if you know +that essentially people react a lot + + align:start position:0% +that essentially people react a lot + + + align:start position:0% +that essentially people react a lot +to price increases um + + align:start position:0% +to price increases um + + + align:start position:0% +to price increases um +compared to price decreases um that + + align:start position:0% +compared to price decreases um that + + + align:start position:0% +compared to price decreases um that +leads to sticky prices essentially so + + align:start position:0% +leads to sticky prices essentially so + + + align:start position:0% +leads to sticky prices essentially so +raising your price above like a pass + + align:start position:0% +raising your price above like a pass + + + align:start position:0% +raising your price above like a pass +price is very costly + + align:start position:0% +price is very costly + + + align:start position:0% +price is very costly +because you lose a lot of customers from + + align:start position:0% +because you lose a lot of customers from + + + align:start position:0% +because you lose a lot of customers from +doing that so now + + align:start position:0% +doing that so now + + + align:start position:0% +doing that so now +lowering your price below the pass price + + align:start position:0% +lowering your price below the pass price + + + align:start position:0% +lowering your price below the pass price +won't actually do very much essentially + + align:start position:0% +won't actually do very much essentially + + + align:start position:0% +won't actually do very much essentially +you're not going to + + align:start position:0% +you're not going to + + + align:start position:0% +you're not going to +generate a lot more extra demand plus + + align:start position:0% +generate a lot more extra demand plus + + + align:start position:0% +generate a lot more extra demand plus +raising the price in the future is + + align:start position:0% +raising the price in the future is + + + align:start position:0% +raising the price in the future is +costly you know essentially once you + + align:start position:0% +costly you know essentially once you + + + align:start position:0% +costly you know essentially once you +lower the price it's hard to get up + + align:start position:0% +lower the price it's hard to get up + + + align:start position:0% +lower the price it's hard to get up +anymore so + + align:start position:0% +anymore so + + + align:start position:0% +anymore so +uh for like these frequently purchased + + align:start position:0% +uh for like these frequently purchased + + + align:start position:0% +uh for like these frequently purchased +items you see a lot of price stickiness + + align:start position:0% +items you see a lot of price stickiness + + + align:start position:0% +items you see a lot of price stickiness +and price equalization + + align:start position:0% +and price equalization + + + align:start position:0% +and price equalization +um across markets across time and + + align:start position:0% +um across markets across time and + + + align:start position:0% +um across markets across time and +products + + align:start position:0% +products + + + align:start position:0% +products +now that's sort of one thing about like + + align:start position:0% +now that's sort of one thing about like + + + align:start position:0% +now that's sort of one thing about like +prices in the world that you would see + + align:start position:0% +prices in the world that you would see + + + align:start position:0% +prices in the world that you would see +but more generally i want to sort of ask + + align:start position:0% +but more generally i want to sort of ask + + + align:start position:0% +but more generally i want to sort of ask +the question in the last few minutes + + align:start position:0% +the question in the last few minutes + + + align:start position:0% +the question in the last few minutes +about like + + align:start position:0% +about like + + + align:start position:0% +about like +if you were a company um suppose you did + + align:start position:0% +if you were a company um suppose you did + + + align:start position:0% +if you were a company um suppose you did +an internship somewhere in the summer + + align:start position:0% +an internship somewhere in the summer + + + align:start position:0% +an internship somewhere in the summer +they told you + + align:start position:0% +they told you + + + align:start position:0% +they told you +um uh you know you you took behavioral + + align:start position:0% +um uh you know you you took behavioral + + + align:start position:0% +um uh you know you you took behavioral +economics uh + + align:start position:0% +economics uh + + + align:start position:0% +economics uh +uh hopefully you learned something but + + align:start position:0% +uh hopefully you learned something but + + + align:start position:0% +uh hopefully you learned something but +like what can we learn about + + align:start position:0% +like what can we learn about + + + align:start position:0% +like what can we learn about +um uh about like the firm policies and + + align:start position:0% +um uh about like the firm policies and + + + align:start position:0% +um uh about like the firm policies and +so + + align:start position:0% +so + + + align:start position:0% +so +on now that you know about loss aversion + + align:start position:0% +on now that you know about loss aversion + + + align:start position:0% +on now that you know about loss aversion +what would you tell them they should do + + align:start position:0% +what would you tell them they should do + + + align:start position:0% +what would you tell them they should do +[Music] + + align:start position:0% + + + + align:start position:0% + +yes having a really high price and then + + align:start position:0% +yes having a really high price and then + + + align:start position:0% +yes having a really high price and then +people + + align:start position:0% + + + + align:start position:0% + +right so that was previously it was + + align:start position:0% +right so that was previously it was + + + align:start position:0% +right so that was previously it was +mentioned is to say you could sort of in + + align:start position:0% +mentioned is to say you could sort of in + + + align:start position:0% +mentioned is to say you could sort of in +particular when you introduce + + align:start position:0% +particular when you introduce + + + align:start position:0% +particular when you introduce +um a price a new product and so on you + + align:start position:0% +um a price a new product and so on you + + + align:start position:0% +um a price a new product and so on you +might want to start at a high price and + + align:start position:0% +might want to start at a high price and + + + align:start position:0% +might want to start at a high price and +then sort of like lowering them and + + align:start position:0% +then sort of like lowering them and + + + align:start position:0% +then sort of like lowering them and +people really like having deals and they + + align:start position:0% +people really like having deals and they + + + align:start position:0% +people really like having deals and they +feel + + align:start position:0% +feel + + + align:start position:0% +feel +good about it notice that that doesn't + + align:start position:0% +good about it notice that that doesn't + + + align:start position:0% +good about it notice that that doesn't +work so well for like + + align:start position:0% +work so well for like + + + align:start position:0% +work so well for like +products that you already have and so on + + align:start position:0% +products that you already have and so on + + + align:start position:0% +products that you already have and so on +because then essentially once you start + + align:start position:0% +because then essentially once you start + + + align:start position:0% +because then essentially once you start +with a high price people get really + + align:start position:0% +with a high price people get really + + + align:start position:0% +with a high price people get really +upset and they + + align:start position:0% +upset and they + + + align:start position:0% +upset and they +you will lose the customers but once you + + align:start position:0% +you will lose the customers but once you + + + align:start position:0% +you will lose the customers but once you +introduce like a new product + + align:start position:0% +introduce like a new product + + + align:start position:0% +introduce like a new product +be it like an iphone or be it like some + + align:start position:0% +be it like an iphone or be it like some + + + align:start position:0% +be it like an iphone or be it like some +whatever new uh + + align:start position:0% +whatever new uh + + + align:start position:0% +whatever new uh +uh computer or whatever it makes a lot + + align:start position:0% +uh computer or whatever it makes a lot + + + align:start position:0% +uh computer or whatever it makes a lot +of sense to start with a really high + + align:start position:0% +of sense to start with a really high + + + align:start position:0% +of sense to start with a really high +price that sort of sets the reference + + align:start position:0% +price that sort of sets the reference + + + align:start position:0% +price that sort of sets the reference +point and then people sort of feel like + + align:start position:0% +point and then people sort of feel like + + + align:start position:0% +point and then people sort of feel like +they go deal get good deals um overall + + align:start position:0% +they go deal get good deals um overall + + + align:start position:0% +they go deal get good deals um overall +what else could you do yes + + align:start position:0% +what else could you do yes + + + align:start position:0% +what else could you do yes +you could offer any single glory + + align:start position:0% +you could offer any single glory + + + align:start position:0% +you could offer any single glory +temporary discounts + + align:start position:0% +temporary discounts + + + align:start position:0% +temporary discounts +the way you keep your reference point + + align:start position:0% +the way you keep your reference point + + + align:start position:0% +the way you keep your reference point +the original price and your + + align:start position:0% +the original price and your + + + align:start position:0% +the original price and your +property for our list + + align:start position:0% +property for our list + + + align:start position:0% +property for our list +exactly that's what a lot of companies + + align:start position:0% +exactly that's what a lot of companies + + + align:start position:0% +exactly that's what a lot of companies +tend to do they tend to do essentially + + align:start position:0% +tend to do they tend to do essentially + + + align:start position:0% +tend to do they tend to do essentially +these like special occasions + + align:start position:0% +these like special occasions + + + align:start position:0% +these like special occasions +we had like black friday and the like + + align:start position:0% +we had like black friday and the like + + + align:start position:0% +we had like black friday and the like +it's not like exactly as you say it's + + align:start position:0% +it's not like exactly as you say it's + + + align:start position:0% +it's not like exactly as you say it's +temporary it's not like a thing that + + align:start position:0% +temporary it's not like a thing that + + + align:start position:0% +temporary it's not like a thing that +prices are uh + + align:start position:0% +prices are uh + + + align:start position:0% +prices are uh +uh permanently lower it's a just right + + align:start position:0% +uh permanently lower it's a just right + + + align:start position:0% +uh permanently lower it's a just right +now you get this like great deal and + + align:start position:0% +now you get this like great deal and + + + align:start position:0% +now you get this like great deal and +then + + align:start position:0% +then + + + align:start position:0% +then +things go back to normal and somehow you + + align:start position:0% +things go back to normal and somehow you + + + align:start position:0% +things go back to normal and somehow you +have to hope that people don't sort of + + align:start position:0% +have to hope that people don't sort of + + + align:start position:0% +have to hope that people don't sort of +adjust the reference point uh towards + + align:start position:0% +adjust the reference point uh towards + + + align:start position:0% +adjust the reference point uh towards +the temporarily lowered + + align:start position:0% +the temporarily lowered + + + align:start position:0% +the temporarily lowered +um price what else + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% + + + + align:start position:0% + +than yes yes + + align:start position:0% +than yes yes + + + align:start position:0% +than yes yes +so if you shop online you might have + + align:start position:0% +so if you shop online you might have + + + align:start position:0% +so if you shop online you might have +wondered lots of companies have this + + align:start position:0% +wondered lots of companies have this + + + align:start position:0% +wondered lots of companies have this +thing i'm like oh you can order whatever + + align:start position:0% +thing i'm like oh you can order whatever + + + align:start position:0% +thing i'm like oh you can order whatever +you want you're like essentially it's + + align:start position:0% +you want you're like essentially it's + + + align:start position:0% +you want you're like essentially it's +like free returns and you kind of wonder + + align:start position:0% +like free returns and you kind of wonder + + + align:start position:0% +like free returns and you kind of wonder +like + + align:start position:0% +like + + + align:start position:0% +like +that seems like a bad deal from the + + align:start position:0% +that seems like a bad deal from the + + + align:start position:0% +that seems like a bad deal from the +company's perspective because people buy + + align:start position:0% +company's perspective because people buy + + + align:start position:0% +company's perspective because people buy +a lot of stuff and send it back + + align:start position:0% +a lot of stuff and send it back + + + align:start position:0% +a lot of stuff and send it back +the hope is exactly as they say it might + + align:start position:0% +the hope is exactly as they say it might + + + align:start position:0% +the hope is exactly as they say it might +be just in part people like to + + align:start position:0% +be just in part people like to + + + align:start position:0% +be just in part people like to +experiment and they like some stuff and + + align:start position:0% +experiment and they like some stuff and + + + align:start position:0% +experiment and they like some stuff and +not others and that's worth doing it + + align:start position:0% +not others and that's worth doing it + + + align:start position:0% +not others and that's worth doing it +but the hope in particular is to say + + align:start position:0% +but the hope in particular is to say + + + align:start position:0% +but the hope in particular is to say +well i want you to try it out for a + + align:start position:0% +well i want you to try it out for a + + + align:start position:0% +well i want you to try it out for a +while you get used to it + + align:start position:0% +while you get used to it + + + align:start position:0% +while you get used to it +then the endowment effect kicks in you + + align:start position:0% +then the endowment effect kicks in you + + + align:start position:0% +then the endowment effect kicks in you +value it more he essentially becomes + + align:start position:0% +value it more he essentially becomes + + + align:start position:0% +value it more he essentially becomes +yours + + align:start position:0% +yours + + + align:start position:0% +yours +and uh then essentially you become lost + + align:start position:0% +and uh then essentially you become lost + + + align:start position:0% +and uh then essentially you become lost +of hers + + align:start position:0% +of hers + + + align:start position:0% +of hers +towards that by the way i should have + + align:start position:0% +towards that by the way i should have + + + align:start position:0% +towards that by the way i should have +mentioned uh this is really + + align:start position:0% +mentioned uh this is really + + + align:start position:0% +mentioned uh this is really +a fascinating book by chaldini who's + + align:start position:0% +a fascinating book by chaldini who's + + + align:start position:0% +a fascinating book by chaldini who's +uh talking about the psychology of + + align:start position:0% +uh talking about the psychology of + + + align:start position:0% +uh talking about the psychology of +persuasion he spent a lot of time with + + align:start position:0% +persuasion he spent a lot of time with + + + align:start position:0% +persuasion he spent a lot of time with +like sales people and particular sort of + + align:start position:0% +like sales people and particular sort of + + + align:start position:0% +like sales people and particular sort of +car sales people and so on trying to + + align:start position:0% +car sales people and so on trying to + + + align:start position:0% +car sales people and so on trying to +learn of what are they actually doing in + + align:start position:0% +learn of what are they actually doing in + + + align:start position:0% +learn of what are they actually doing in +markets + + align:start position:0% +markets + + + align:start position:0% +markets +and he has these like amazing stories of + + align:start position:0% +and he has these like amazing stories of + + + align:start position:0% +and he has these like amazing stories of +like sales people what's all sorts of + + align:start position:0% +like sales people what's all sorts of + + + align:start position:0% +like sales people what's all sorts of +tricks they they use + + align:start position:0% +tricks they they use + + + align:start position:0% +tricks they they use +it's psychologically extremely rich and + + align:start position:0% +it's psychologically extremely rich and + + + align:start position:0% +it's psychologically extremely rich and +interesting in terms of just trying to + + align:start position:0% +interesting in terms of just trying to + + + align:start position:0% +interesting in terms of just trying to +understand what people do + + align:start position:0% +understand what people do + + + align:start position:0% +understand what people do +and that ranges from things like you + + align:start position:0% +and that ranges from things like you + + + align:start position:0% +and that ranges from things like you +know once you um + + align:start position:0% +know once you um + + + align:start position:0% +know once you um +uh purchase a car they let you like test + + align:start position:0% +uh purchase a car they let you like test + + + align:start position:0% +uh purchase a car they let you like test +drive in the car and you sit in it and + + align:start position:0% +drive in the car and you sit in it and + + + align:start position:0% +drive in the car and you sit in it and +it feels like yours and then + + align:start position:0% +it feels like yours and then + + + align:start position:0% +it feels like yours and then +you know or when you try to buy a house + + align:start position:0% +you know or when you try to buy a house + + + align:start position:0% +you know or when you try to buy a house +you know then people would say like oh + + align:start position:0% +you know then people would say like oh + + + align:start position:0% +you know then people would say like oh +you know this will be your living room + + align:start position:0% +you know this will be your living room + + + align:start position:0% +you know this will be your living room +and this is where your baby is going to + + align:start position:0% +and this is where your baby is going to + + + align:start position:0% +and this is where your baby is going to +sleep and like + + align:start position:0% +sleep and like + + + align:start position:0% +sleep and like +you know there's lots of sort of ways in + + align:start position:0% +you know there's lots of sort of ways in + + + align:start position:0% +you know there's lots of sort of ways in +which people make sort of something feel + + align:start position:0% +which people make sort of something feel + + + align:start position:0% +which people make sort of something feel +yours and really try to sort of get the + + align:start position:0% +yours and really try to sort of get the + + + align:start position:0% +yours and really try to sort of get the +endowment effect um + + align:start position:0% +endowment effect um + + + align:start position:0% +endowment effect um +uh to kick in if you were to work in an + + align:start position:0% +uh to kick in if you were to work in an + + + align:start position:0% +uh to kick in if you were to work in an +insurance firm what would you do like + + align:start position:0% +insurance firm what would you do like + + + align:start position:0% +insurance firm what would you do like +somebody who offers insurance in one way + + align:start position:0% +somebody who offers insurance in one way + + + align:start position:0% +somebody who offers insurance in one way +or the other + + align:start position:0% +or the other + + + align:start position:0% +or the other +or products that offer insurance in some + + align:start position:0% +or products that offer insurance in some + + + align:start position:0% +or products that offer insurance in some +ways + + align:start position:0% + + + + align:start position:0% + +yes we talked about this a little bit in + + align:start position:0% +yes we talked about this a little bit in + + + align:start position:0% +yes we talked about this a little bit in +the previous class + + align:start position:0% +the previous class + + + align:start position:0% +the previous class +but uh this is why i think companies + + align:start position:0% +but uh this is why i think companies + + + align:start position:0% +but uh this is why i think companies +will sell things like apple care or + + align:start position:0% +will sell things like apple care or + + + align:start position:0% +will sell things like apple care or +operational warranties because they can + + align:start position:0% +operational warranties because they can + + + align:start position:0% +operational warranties because they can +they know they'll make money off of it + + align:start position:0% +they know they'll make money off of it + + + align:start position:0% +they know they'll make money off of it +because people tend to overinsure + + align:start position:0% +because people tend to overinsure + + + align:start position:0% +because people tend to overinsure +exactly there's lots of different + + align:start position:0% +exactly there's lots of different + + + align:start position:0% +exactly there's lots of different +products where there's extended + + align:start position:0% +products where there's extended + + + align:start position:0% +products where there's extended +warranties and all sorts of like things + + align:start position:0% +warranties and all sorts of like things + + + align:start position:0% +warranties and all sorts of like things +like apple care etc + + align:start position:0% +like apple care etc + + + align:start position:0% +like apple care etc +where people are like very risk-averse + + align:start position:0% +where people are like very risk-averse + + + align:start position:0% +where people are like very risk-averse +what it looks like presumably loss of + + align:start position:0% +what it looks like presumably loss of + + + align:start position:0% +what it looks like presumably loss of +errors + + align:start position:0% +errors + + + align:start position:0% +errors +um where in fact you know they actually + + align:start position:0% +um where in fact you know they actually + + + align:start position:0% +um where in fact you know they actually +the claim rate tends to be very low + + align:start position:0% +the claim rate tends to be very low + + + align:start position:0% +the claim rate tends to be very low +so you can make a lot of money with this + + align:start position:0% +so you can make a lot of money with this + + + align:start position:0% +so you can make a lot of money with this +by saying like yes i'm going to exchange + + align:start position:0% +by saying like yes i'm going to exchange + + + align:start position:0% +by saying like yes i'm going to exchange +it in this and that + + align:start position:0% +it in this and that + + + align:start position:0% +it in this and that +because essentially it doesn't happen + + align:start position:0% +because essentially it doesn't happen + + + align:start position:0% +because essentially it doesn't happen +that often at the end of the day + + align:start position:0% +that often at the end of the day + + + align:start position:0% +that often at the end of the day +even if there's like moral hazard or + + align:start position:0% +even if there's like moral hazard or + + + align:start position:0% +even if there's like moral hazard or +other issues so people not treating + + align:start position:0% +other issues so people not treating + + + align:start position:0% +other issues so people not treating +their stuff that well once they have + + align:start position:0% +their stuff that well once they have + + + align:start position:0% +their stuff that well once they have +insurance what about wage setting + + align:start position:0% + + + + align:start position:0% + +like when you when you set your your + + align:start position:0% +like when you when you set your your + + + align:start position:0% +like when you when you set your your +employees wages + + align:start position:0% + + + + align:start position:0% + +yeah could that be linked to mass + + align:start position:0% +yeah could that be linked to mass + + + align:start position:0% +yeah could that be linked to mass +unemployment in recessions because + + align:start position:0% +unemployment in recessions because + + + align:start position:0% +unemployment in recessions because +you know that if you lower the wage then + + align:start position:0% +you know that if you lower the wage then + + + align:start position:0% +you know that if you lower the wage then +morale will go down a lot + + align:start position:0% +morale will go down a lot + + + align:start position:0% +morale will go down a lot +and you could actually decide just to + + align:start position:0% +and you could actually decide just to + + + align:start position:0% +and you could actually decide just to +kick them out + + align:start position:0% +kick them out + + + align:start position:0% +kick them out +right so exactly so there is um + + align:start position:0% +right so exactly so there is um + + + align:start position:0% +right so exactly so there is um +there is um a large uh literature + + align:start position:0% +there is um a large uh literature + + + align:start position:0% +there is um a large uh literature +on uh wage stickiness um + + align:start position:0% +on uh wage stickiness um + + + align:start position:0% +on uh wage stickiness um +essentially exactly as you say + + align:start position:0% +essentially exactly as you say + + + align:start position:0% +essentially exactly as you say +where people are extremely reluctant to + + align:start position:0% +where people are extremely reluctant to + + + align:start position:0% +where people are extremely reluctant to +lower wages + + align:start position:0% +lower wages + + + align:start position:0% +lower wages +companies are very reluctant to lower + + align:start position:0% +companies are very reluctant to lower + + + align:start position:0% +companies are very reluctant to lower +wages because essentially workers are + + align:start position:0% +wages because essentially workers are + + + align:start position:0% +wages because essentially workers are +really unhappy + + align:start position:0% +really unhappy + + + align:start position:0% +really unhappy +so once you and these are like often + + align:start position:0% +so once you and these are like often + + + align:start position:0% +so once you and these are like often +nominal wages or real wages it doesn't + + align:start position:0% +nominal wages or real wages it doesn't + + + align:start position:0% +nominal wages or real wages it doesn't +really matter that much but usually it's + + align:start position:0% +really matter that much but usually it's + + + align:start position:0% +really matter that much but usually it's +nominal wages + + align:start position:0% +nominal wages + + + align:start position:0% +nominal wages +people really really dislike nominal + + align:start position:0% +people really really dislike nominal + + + align:start position:0% +people really really dislike nominal +wage + + align:start position:0% +wage + + + align:start position:0% +wage +reductions and so now in some times when + + align:start position:0% +reductions and so now in some times when + + + align:start position:0% +reductions and so now in some times when +uh companies would actually need to + + align:start position:0% +uh companies would actually need to + + + align:start position:0% +uh companies would actually need to +lower wages + + align:start position:0% +lower wages + + + align:start position:0% +lower wages +and sort of to be able to keep workers + + align:start position:0% +and sort of to be able to keep workers + + + align:start position:0% +and sort of to be able to keep workers +not to make losses + + align:start position:0% +not to make losses + + + align:start position:0% +not to make losses +companies might rather sort of fire some + + align:start position:0% +companies might rather sort of fire some + + + align:start position:0% +companies might rather sort of fire some +workers + + align:start position:0% + + + + align:start position:0% + +rather than sort of lowering the wages + + align:start position:0% +rather than sort of lowering the wages + + + align:start position:0% +rather than sort of lowering the wages +for everybody because essentially + + align:start position:0% +for everybody because essentially + + + align:start position:0% +for everybody because essentially +the remaining workers once you lower + + align:start position:0% +the remaining workers once you lower + + + align:start position:0% +the remaining workers once you lower +wages for everybody everybody would be + + align:start position:0% +wages for everybody everybody would be + + + align:start position:0% +wages for everybody everybody would be +unhappy if you just + + align:start position:0% +unhappy if you just + + + align:start position:0% +unhappy if you just +fire one worker everybody else will be + + align:start position:0% +fire one worker everybody else will be + + + align:start position:0% +fire one worker everybody else will be +less unhappy than about their wage + + align:start position:0% +less unhappy than about their wage + + + align:start position:0% +less unhappy than about their wage +reductions similarly + + align:start position:0% +reductions similarly + + + align:start position:0% +reductions similarly +firms are reluctant to hire people at + + align:start position:0% +firms are reluctant to hire people at + + + align:start position:0% +firms are reluctant to hire people at +lower wages if there's other people who + + align:start position:0% +lower wages if there's other people who + + + align:start position:0% +lower wages if there's other people who +make higher wages because people really + + align:start position:0% +make higher wages because people really + + + align:start position:0% +make higher wages because people really +dislike wage dispersion + + align:start position:0% +dislike wage dispersion + + + align:start position:0% +dislike wage dispersion +so essentially overall you want to to + + align:start position:0% +so essentially overall you want to to + + + align:start position:0% +so essentially overall you want to to +avoid wage cuts as much as possible + + align:start position:0% +avoid wage cuts as much as possible + + + align:start position:0% +avoid wage cuts as much as possible +and that leads to essentially then the + + align:start position:0% +and that leads to essentially then the + + + align:start position:0% +and that leads to essentially then the +macroeconomic inefficiencies and people + + align:start position:0% +macroeconomic inefficiencies and people + + + align:start position:0% +macroeconomic inefficiencies and people +have argued in particular it leads to + + align:start position:0% +have argued in particular it leads to + + + align:start position:0% +have argued in particular it leads to +like + + align:start position:0% +like + + + align:start position:0% +like +unemployment because essentially uh + + align:start position:0% +unemployment because essentially uh + + + align:start position:0% +unemployment because essentially uh +wages are not going down as much as they + + align:start position:0% +wages are not going down as much as they + + + align:start position:0% +wages are not going down as much as they +should + + align:start position:0% +should + + + align:start position:0% +should +in recessions and that's bad for firms + + align:start position:0% +in recessions and that's bad for firms + + + align:start position:0% +in recessions and that's bad for firms +and therefore they hire fewer workers to + + align:start position:0% +and therefore they hire fewer workers to + + + align:start position:0% +and therefore they hire fewer workers to +retain fewer workers overall + + align:start position:0% +retain fewer workers overall + + + align:start position:0% +retain fewer workers overall +i think i mentioned we mentioned all of + + align:start position:0% +i think i mentioned we mentioned all of + + + align:start position:0% +i think i mentioned we mentioned all of +those uh uh kind of things + + align:start position:0% +those uh uh kind of things + + + align:start position:0% +those uh uh kind of things +so now um another thing that sort of + + align:start position:0% +so now um another thing that sort of + + + align:start position:0% +so now um another thing that sort of +that's sort of like what firms are doing + + align:start position:0% +that's sort of like what firms are doing + + + align:start position:0% +that's sort of like what firms are doing +now another thing you might think about + + align:start position:0% +now another thing you might think about + + + align:start position:0% +now another thing you might think about +is like what are you going to actually + + align:start position:0% +is like what are you going to actually + + + align:start position:0% +is like what are you going to actually +do in your real lives + + align:start position:0% +do in your real lives + + + align:start position:0% +do in your real lives +um i think there's many different things + + align:start position:0% +um i think there's many different things + + + align:start position:0% +um i think there's many different things +that you can actually think about is + + align:start position:0% +that you can actually think about is + + + align:start position:0% +that you can actually think about is +like + + align:start position:0% +like + + + align:start position:0% +like +the framing of situations for example + + align:start position:0% +the framing of situations for example + + + align:start position:0% +the framing of situations for example +can make a big difference if you + + align:start position:0% +can make a big difference if you + + + align:start position:0% +can make a big difference if you +present something to your friends + + align:start position:0% +present something to your friends + + + align:start position:0% +present something to your friends +different options whether you whether + + align:start position:0% +different options whether you whether + + + align:start position:0% +different options whether you whether +you present that as like gains or losses + + align:start position:0% +you present that as like gains or losses + + + align:start position:0% +you present that as like gains or losses +makes a big difference potentially + + align:start position:0% +makes a big difference potentially + + + align:start position:0% +makes a big difference potentially +managing people's expectations is really + + align:start position:0% +managing people's expectations is really + + + align:start position:0% +managing people's expectations is really +important if there's like + + align:start position:0% +important if there's like + + + align:start position:0% +important if there's like +some big goal that they could reach or + + align:start position:0% +some big goal that they could reach or + + + align:start position:0% +some big goal that they could reach or +some lower goal they could they could + + align:start position:0% +some lower goal they could they could + + + align:start position:0% +some lower goal they could they could +reach if you sort of oversell the high + + align:start position:0% +reach if you sort of oversell the high + + + align:start position:0% +reach if you sort of oversell the high +chance of like + + align:start position:0% +chance of like + + + align:start position:0% +chance of like +reaching some big goal they might reach + + align:start position:0% +reaching some big goal they might reach + + + align:start position:0% +reaching some big goal they might reach +the other goal that's actually pretty + + align:start position:0% +the other goal that's actually pretty + + + align:start position:0% +the other goal that's actually pretty +good might + + align:start position:0% +good might + + + align:start position:0% +good might +feel like really disappointed about that + + align:start position:0% +feel like really disappointed about that + + + align:start position:0% +feel like really disappointed about that +be it in job search or the like + + align:start position:0% +be it in job search or the like + + + align:start position:0% +be it in job search or the like +so managing people's expectations + + align:start position:0% +so managing people's expectations + + + align:start position:0% +so managing people's expectations +including your own expectations + + align:start position:0% +including your own expectations + + + align:start position:0% +including your own expectations +seems really important there's something + + align:start position:0% +seems really important there's something + + + align:start position:0% +seems really important there's something +about aggregating losses and gains which + + align:start position:0% +about aggregating losses and gains which + + + align:start position:0% +about aggregating losses and gains which +essentially is to say + + align:start position:0% +essentially is to say + + + align:start position:0% +essentially is to say +since people seem to be um uh + + align:start position:0% +since people seem to be um uh + + + align:start position:0% +since people seem to be um uh +uh risk averse over gains and um so + + align:start position:0% +uh risk averse over gains and um so + + + align:start position:0% +uh risk averse over gains and um so +since the value function is concave + + align:start position:0% +since the value function is concave + + + align:start position:0% +since the value function is concave +over gains and convex over losses um + + align:start position:0% +over gains and convex over losses um + + + align:start position:0% +over gains and convex over losses um +what you should do is potentially as + + align:start position:0% +what you should do is potentially as + + + align:start position:0% +what you should do is potentially as +like be really careful about like + + align:start position:0% +like be really careful about like + + + align:start position:0% +like be really careful about like +when you give people uh a positive or + + align:start position:0% +when you give people uh a positive or + + + align:start position:0% +when you give people uh a positive or +negative + + align:start position:0% +negative + + + align:start position:0% +negative +um feedback or like bonuses and so on uh + + align:start position:0% +um feedback or like bonuses and so on uh + + + align:start position:0% +um feedback or like bonuses and so on uh +you might want to sort of be + + align:start position:0% +you might want to sort of be + + + align:start position:0% +you might want to sort of be +be careful like uh whether you uh + + align:start position:0% +be careful like uh whether you uh + + + align:start position:0% +be careful like uh whether you uh +aggregate the losses or + + align:start position:0% +aggregate the losses or + + + align:start position:0% +aggregate the losses or +so aggregating losses makes sense + + align:start position:0% +so aggregating losses makes sense + + + align:start position:0% +so aggregating losses makes sense +because it's essentially it's like um + + align:start position:0% +because it's essentially it's like um + + + align:start position:0% +because it's essentially it's like um +convex in the lost domain as opposed to + + align:start position:0% +convex in the lost domain as opposed to + + + align:start position:0% +convex in the lost domain as opposed to +like you want to give small increments + + align:start position:0% +like you want to give small increments + + + align:start position:0% +like you want to give small increments +of gains + + align:start position:0% +of gains + + + align:start position:0% +of gains +um overall now one thing that i do want + + align:start position:0% +um overall now one thing that i do want + + + align:start position:0% +um overall now one thing that i do want +to mention is like you want to be kind + + align:start position:0% +to mention is like you want to be kind + + + align:start position:0% +to mention is like you want to be kind +of very careful with last framed + + align:start position:0% +of very careful with last framed + + + align:start position:0% +of very careful with last framed +incentives + + align:start position:0% +incentives + + + align:start position:0% +incentives +there's a company who is trying to do + + align:start position:0% +there's a company who is trying to do + + + align:start position:0% +there's a company who is trying to do +this um uh and + + align:start position:0% +this um uh and + + + align:start position:0% +this um uh and +trying to give essentially these are + + align:start position:0% +trying to give essentially these are + + + align:start position:0% +trying to give essentially these are +like car manufacturers were trying to + + align:start position:0% +like car manufacturers were trying to + + + align:start position:0% +like car manufacturers were trying to +give essentially their car dealers + + align:start position:0% +give essentially their car dealers + + + align:start position:0% +give essentially their car dealers +incentives + + align:start position:0% +incentives + + + align:start position:0% +incentives +um sort of uh targets + + align:start position:0% +um sort of uh targets + + + align:start position:0% +um sort of uh targets +in their um for their sales of of their + + align:start position:0% +in their um for their sales of of their + + + align:start position:0% +in their um for their sales of of their +their cars what essentially happened at + + align:start position:0% +their cars what essentially happened at + + + align:start position:0% +their cars what essentially happened at +the end of the day is like there was a + + align:start position:0% +the end of the day is like there was a + + + align:start position:0% +the end of the day is like there was a +bunch of um + + align:start position:0% +bunch of um + + + align:start position:0% +bunch of um +multitasking is like the company or the + + align:start position:0% +multitasking is like the company or the + + + align:start position:0% +multitasking is like the company or the +car sales people were essentially + + align:start position:0% +car sales people were essentially + + + align:start position:0% +car sales people were essentially +selling certain cars but they're not + + align:start position:0% +selling certain cars but they're not + + + align:start position:0% +selling certain cars but they're not +others and we're essentially + + align:start position:0% +others and we're essentially + + + align:start position:0% +others and we're essentially +multitasking and then sort of + + align:start position:0% +multitasking and then sort of + + + align:start position:0% +multitasking and then sort of +reverting uh sort of reallocating + + align:start position:0% +reverting uh sort of reallocating + + + align:start position:0% +reverting uh sort of reallocating +efforts to one thing versus the other + + align:start position:0% +efforts to one thing versus the other + + + align:start position:0% +efforts to one thing versus the other +which then seemed like a really good + + align:start position:0% +which then seemed like a really good + + + align:start position:0% +which then seemed like a really good +idea there was a recent evaluation that + + align:start position:0% +idea there was a recent evaluation that + + + align:start position:0% +idea there was a recent evaluation that +sort of showed that + + align:start position:0% +sort of showed that + + + align:start position:0% +sort of showed that +um that was actually pretty bad idea and + + align:start position:0% +um that was actually pretty bad idea and + + + align:start position:0% +um that was actually pretty bad idea and +the company would have lost a lot of + + align:start position:0% +the company would have lost a lot of + + + align:start position:0% +the company would have lost a lot of +money overall + + align:start position:0% +money overall + + + align:start position:0% +money overall +if this had been uh scaled we're gonna + + align:start position:0% +if this had been uh scaled we're gonna + + + align:start position:0% +if this had been uh scaled we're gonna +have this the the dlr no deal and the + + align:start position:0% +have this the the dlr no deal and the + + + align:start position:0% +have this the the dlr no deal and the +specific paper and recitation to tell + + align:start position:0% +specific paper and recitation to tell + + + align:start position:0% +specific paper and recitation to tell +you in more detail + + align:start position:0% +you in more detail + + + align:start position:0% +you in more detail +because i want to move towards social + + align:start position:0% +because i want to move towards social + + + align:start position:0% +because i want to move towards social +preferences next time + + align:start position:0% +preferences next time + + + align:start position:0% +preferences next time +uh so as i said next time we talk about + + align:start position:0% +uh so as i said next time we talk about + + + align:start position:0% +uh so as i said next time we talk about +social preferences bring your laptop and + + align:start position:0% +social preferences bring your laptop and + + + align:start position:0% +social preferences bring your laptop and +i'll send you further instructions + + align:start position:0% +i'll send you further instructions + + + align:start position:0% +i'll send you further instructions +thank you \ No newline at end of file diff --git a/SI_GKdFQmds.txt b/SI_GKdFQmds.txt new file mode 100644 index 0000000000000000000000000000000000000000..e429f25f84953b3f1363203c330c8dc5265f1421 --- /dev/null +++ b/SI_GKdFQmds.txt @@ -0,0 +1,4081 @@ +The following content is +provided under a Creative + +Commons license. + +Your support will help MIT +OpenCourseWare continue to + +offer high quality educational +resources for free. + +To make a donation, or view +additional materials from + +hundreds of MIT courses, visit +MIT OpenCourseWare at + +ocw.mit.edu. + +PROFESSOR: Mike Acton today +who has done a lot of + +programming on cell and also +done a lot of game + +development. + +He came from California just +like this today and + +[OBSCURED]. + +MIKE ACTON: Yeah, it's +really cool. + +I'll tell you. + +PROFESSOR: He's going to talk +about what it's really like to + +use cell and PS3 and what it's +like to program games. + +So I think it's going +to be a fun lecture. + +MIKE ACTON: All right, so +anyway, I'm the Engine + +Director at Insomniac Games. + +I've only recently taken that +position, previously I was + +working on PS3 technology at +Highmoon studios, which is + +with vin studios. + +And I've worked at Sony. + +I've worked for Titus, and +Bluesky Studios in San Diego. + +And I've been doing game +development, 11, 12 years. + +Before that I was working +in simulation. + +So, the PlayStation 3 is +a really fun platform. + +And I know you guys have been +working on cell development. + +Working with the PS3 +under Linux. + +Working as developers for the +PS3 is definitely a different + +environment from that. + +I think I'm going to concentrate +more on the + +high-level aspects of how you +design a game for the cell. + +And how the cell would impact +the design, and what are the + +elements of the game. + +Just stuff that you probably +haven't had as part of this + +course that you might +find interesting. + +And you can feel free to +interrupt me at any time with + +questions or whatever +you'd like. + +So just, I wanted to go over, +briefly, some of the different + +types of game development and +what the trade-offs for each + +one of them are. + +Casual games, console games, +PC games, blah, blah, blah. + +Casual games, basically, are the +small, simple games that + +you would download on +the PC, or you would + +see on Yahoo or whatever. + +And those generally don't have +really strict performance + +requirements. + +Where a console game, we have +this particular advantage of + +knowing the hardware and the +hardware doesn't change for an + +entire cycle. + +So for five, six years, we have + +exactly the same hardware. + +And that's definitely an +advantage from a performance + +point anyway. + +In this case, it's +PlayStation 3. + +As far as develpment priorities, +development + +priorities for a console game-- +and especially a PS3 + +game-- development would be +completely different than you + +might find on another +kind of application. + +We don't really consider the +code itself important at all. + +The real value is in +the programmers. + +The real value is in +the experience, + +and is in those skills. + +Code is disposable. + +After six years, when we start +a new platform we pretty much + +have to rewrite it anyway, so +there's not much point in + +trying to plan for a long +life span of code. + +Especially when you have +optimized code written in + +assembly for a particular +platform. + +And to that end, the data is +way more significant to the + +performance than the +code, anyway. + +And the data is specific +to a particular game. + +Or specific to a particular +type of game. + +And certainly specific to +a studios pipeline. + +And it's the design of the data +where you really want to + +spend your time concentrating, +especially for the PS3. + +Ease of programming-- whether +or not it's easier to do + +parallelism is not a major +concern at all. + +If it's hard, so what? + +You do it. + +That's it. + +Portability, runs on PlayStation +3, doesn't run + +anywhere else. + +That's a non-concern. + +And everything is about +performance. + +Everything we do. + +A vast majority of our code is +either hand up from IC, or + +assembly, very little +high level code. + +Some of our gameplay programmers +will write C plus + +plus for the high level logic, +but as a general, most of the + +code that's running most the +time is definitely optimized. + +Yeah? + +AUDIENCE: If programming is a +non-priority, does that mean + +to say that if you're developing +more than one + +product or game, they don't +share any common + +infrastructure or need? + +MIKE ACTION: No, that's +not necessarily true. + +If we have games that share +similar needs, they can + +definitely share similar code. + +I mean, the point I'm trying to +make is, let's say in order + +to make something fast it +has to be complicated. + +So be it, it's complicated. + +Whether or not it's easy to use +for another programmer is + +not a major concern. + +AUDIENCE: So you wish +it was easier? + +MIKE ACTION: No. + +I don't care. + +That's my point. + +AUDIENCE: Well, it's not as +important as performance, but + +if someone came to you with a +high performance tool, you + +would like to use it? + +MIKE ACTION: I doubt +they could. + +The highest performance tool +that exists is the brains of + +the programmers on our team. + +You can not create-- + +it's theoretically impossible. + +You can not out perform people +who are customizing for the + +data, for the context +for the game. + +It is not even remotely +theoretically possible. + +AUDIENCE: That didn't come out +in assembly programming for + +general purpose but we'll +take this offline? + +And there was a day when that +was also true for general + +preferred cleary at the time, +but it's no longer true. + +MIKE ACTION: It is +absolutely-- + +AUDIENCE: So the average person +prefers to go on -- + +take it offline. + +MIKE ACTION: Average person. + +We're not the average people. + +We're game programmers. + +Yeah? + +AUDIENCE: So does cost +ever become an issue? + +I mean-- + +MIKE ACTION: Absolutely, cost +does become an issue. + +At a certain pont, something +is so difficult that you + +either have to throw up +your hands or you + +can't finish in time. + +AUDIENCE: Do you ever +hit that point? + +MIKE ACTION: Or you figure out +a new way of doing it. + +Or do a little bit less. + +I mean we do have to prioritize + +what you want to do. + +At the end of the day you can't +do everything you want + +to do, and you have another +game you need to ship + +eventually, anyway. + +So, a lot of times you do +end up tabling things. + +And say, look we can get 50% +more performance out of this, + +but we're going to have to table +that for now and scale + +back on the content. + +And that's why you have six +years of development. + +You know, maybe in the next +cycle, in the next game, + +you'll be able to squeeze +out a little bit more. + +And the next one you squeeze +out a little bit more. + +That's sort of this continuous +development, and continuous + +optimization over the course +of a platform. + +And sometimes, yeah, I mean +occasionally you just say + +yeah, we can't do it or +whatever, it doesn't work. + +I mean, that's part and parcel +of development in general. + +Some ideas just don't pan out. + +But-- + +AUDIENCE: Have you ever come +into a situation where + +programming conflicts just +kills a project? + +Like Microsoft had had a few +times, like they couldn't put + +out [OBSCURED]. + +Couldn't release for-- + +MIKE ACTION: Sure, there's +plenty of studios where the + +programming complexity has +killed the studio, or killed + +the project. + +But I find it hard to believe-- +or it's very + +rarely-- because it's complexity +that has to do + +specifically with +optimization. + +That complexity usually has +to do with unnecessary + +complexity. + +Complexity that doesn't +achieve anything. + +Organization for the sake +of organization. + +So you have these sort of over +designed C plus plus + +hierarchies just for the sake +of over organizing things. + +That's what will generally +kill a project. + +But in performance, the +complexity tends to come from + +the rule set-- what you need +to do to set it up. + +But the code tends to be smaller +when it's faster. + +You tend to be doing one +thing and doing one + +thing really well. + +So it doesn't tend to +get out of hand. + +I mean, it occasionally +happens but, yeah? + +AUDIENCE: So in terms of the +overall cost, how big is this + +programming versus the +other aspect of + +coming up with the game? + +Like the game design, +the graphics-- + +AUDIENCE: So, for example, +do you have-- + +MIKE ACTION: OK, development +team? + +So-- + +AUDIENCE: So how many +programmers, how many + +artists, how many-- + +PROFESSOR: Maybe, let's-- so +for example, like, now it's + +like, what, $20 million +to deliver a PS3 game? + +MIKE ACTION: Between $10 +and $20 million, yeah. + +PROFESSOR: So let's +develop [OBSCURED] + +MIKE ACTION: So artists +are by far the most-- + +the largest group +of developers. + +So you have animators and shade +artists, and textual + +artists, and modelers, +and enviromental + +artists, and lighters. + +And so they'll often outnumber +programmers 2:1. + +Which is completely different +than-- certainly very + +different from PlayStation and +the gap is much larger than it + +was on PlayStation 2. + +With programmers you tend to +have a fairly even split or + +you tend to have a divide +between the high level game + +play programmers and the low +level engine programmers. + +And you will tend to have more +game play programmers than + +engine programmers, although +most-- the majority of the CPU + +time is spent in the +engine code. + +And that partially comes down +to education and experience. + +In order to get high performance +code you need to + +have that experience. + +You need to know how +to optimize. + +You need to understand +the machine. + +You need to understand the +architecture and you need to + +understand the data. + +And there's only so many people +that can do that on any + +particular team. + +AUDIENCE: Code size wise, How +is the code size divided + +between game playing and +AI, special effects? + +MIKE ACTION: Just like, +the amount of code? + +AUDIENCE: Yeah, it should +be small I guess. + +MIKE ACTION: Yeah, I mean, +it's hard to say. + +I mean, because it depends +on how many + +features you're using. + +And, you know sort of the scope +of the engine is how + +much is being used for a +particular game, especially if + +you're targeting multiple +games within a studio. + +But quite often-- interestingly +enough-- the + +game play code actually +overwhelms the engine code in + +terms of size and that is back +to basically what I was saying + +that the engine code tends to do +one thing really well or a + +series of things really well. + +AUDIENCE: Game play code +also C plus plus? + +MIKE ACTON: These days it's +much more likely that game + +play code is C plus plus in +the high level and kills + +performance and doesn't think +about things like cache. + +That's actually part of the +problem with PlayStation 3 + +development. + +It was part of the challenge +that we've had with + +PlayStation 3 development. + +Is in the past, certainly with +PlayStation 2 and definitely + +on any previous console, this +divide between game play and + +engine worked very well. + +The game play programmers could +just call a function and + +it did its fat thing really fast +and it came back and they + +continue this, but in a serial +program on one process that + +model works very well. + +But now when the high level +design can destroy performance + +but through the simplest +decision, like for example, in + +collision detection if the logic +assumes that the result + +is immediately available there's +virtually no way of + +making that fast. So the +high-level design has to + +conform to the hardware. + +That's sort of a challenge +now, is introducing those + +concepts to the high-level +programmer who haven't + +traditionally had +to deal with it. + +Does that answer that question +as far as the split? + +AUDIENCE: You said 2:1, right? + +MIKE ACTON: Approximately 2:1, +artist to programmers. + +It varies studio to studio and +team to team, so it's hard to + +say in the industry +as a whole. + +So back basically to the +point of the code + +isn't really important. + +The code itself doesn't +have a lot of value. + +There are fundamental things +that affect how you would + +design it in the first place. + +The type of game, the kind of +engine that would run a racing + +game is completely different +than the kind of engine that + +would run a first +person shooter. + +The needs are different, the +optimizations are totally + +different, the data is totally +different, so you wouldn't try + +to reuse code from +one to the other. + +It just either wouldn't +work or would work + +really, really poorly. + +The framerate-- + +having a target of 30 frames per +second is a much different + +problem than having a target +of 60 frames per second. + +And in the NCSC territories +those are pretty much your + +only two choices- 30 frames or +60, which means everything has + +to be done in 16 and +2/3 milliseconds. + +That's it, that's +what you have-- + +432 milliseconds. + +Of course, back to schedule +and cost, how much? + +You know, do you have a two year +cycle, one year cycle, + +how much can you get done? + +The kind of hardware. + +So taking for example, an engine +from PlayStation 2 and + +trying to move it to PlayStation +3 is sort of a + +lost cause. + +The kind of optimizations that +you would do, the kind of + +parallelization you would do +is so completely different, + +although there was +parallelization in PlayStation + +2, the choices would have been +completely different. + +The loss from trying to port it +is much, much greater than + +the cost of just +doing it again. + +AUDIENCE: [OBSCURED] + +MIKE ACTON: I don't know that +there's an average. + +I mean, if you wanted to just +like homogenize the industry, + +it's probably 18 months. + +The compiler actually makes a +huge, significant difference + +in how you design your code. + +If you're working with GCC and +you have programmers who have + +been working with GCC for 15 +years abd who understand the + +intricacies and issues involved +in GCC, the kind of + +code you would write would be +completely different than if + +you were using XLC for +example, on the cell. + +There are studios-- + +Insomniac doesn't, but there are +other studios who do cross + +platform design. + +So for example, write +Playstation 3 games and Xbox + +360 games and/or PC titles. + +At the moment, probably the +easiest approach for that is + +to target the PlayStation 3. + +So you have these sort of SPU +friendly chunks of processing + +SPU chunks, friendly chunks of +data and move those onto + +homogenous parallel +processors. + +It's not the perfect solution, +but virtually all cross + +platform titles are not looking +for the perfect + +solution anyway because they +cannot fully optimize for any + +particular platform. + +I wanted to go through-- + +these are a basic list of some +of the major modules that a + +game is made out of. + +I'll go through some of these +and explain how designing on + +the cell impacts the system. + +I'm not going to bother +reading them. + +I assume you all can read. + +So yeah, I'm going to go over +the major system, a few of the + +major systems and then we're +going to drive a little bit + +into a specific system, in this +case an animation system. + +And just talk it through, +basically you see how each of + +these steps are affected by +the hardware that we're + +running on it. + +So just to start with when +you're designing a structure, + +any structure, anywhere-- + +the initial structure is +affected by the kind of + +hardware that you're running. + +And in this particular case on +the SPU and there are other + +processors where this is equally +true, but in this + +conventional structure where +you say structure class or + +whatever and you have +domain-constrained structures + +are of surprisingly +little use. + +In general, the data is either +compressed or is in a stram or + +is in blocks. + +It's sort of based on type, +which means that there's no + +fixed size struct that you +could define anyway. + +So as a general rule, the +structure of the data is + +defined within the +code as opposed + +to in a struct somewhere. + +And that's really to get the +performance from the data, you + +group things of similar type +together rather than for + +example, on SPU, having flags +that say this is of type A and + +this is of type B. Any flag +implies a branch, which is-- + +I'm sure you all know at this +point-- is really poor + +performing on SPU. + +So basically, pull flags out, +resort everything and then + +move things in streams. And all +of these types are going + +to be of varying sizes. + +In which case there's very +little point to define those + +structures in the first place +because you can't change them. + +And the fact that you're +accessing data + +in quadwords anyway. + +You're always either loading and +storing in quadwords, not + +on scalars, so having scalar +fields in a structure is sort + +of pointless. + +So again, only SPU generally +speaking + +structures are of much use. + +When you go to define structures +in general you need + +to consider things like the +cache, the TLB, how that's + +going to affect you're reading +out of the structure or + +writing to the structure. + +More to the point of you cannot +just assume that if + +you've written some data +definition that you can port + +it to another platform. + +It's very easy to be poorly, a + +performing platform to platform. + +In this case, when we design +structures you have to + +consider the fundamental +units of the cell. + +The cache line is a fundamental +unit of the cell. + +Basically, you want to define +things in terms of + +128 bytes of wide. + +What can you fit in there +because you read one you read + +them all, so you want to pack +as much as possible into 128 + +bytes and just deal with that +as a fundamental unit. + +16 bytes, of course, you're +doing load and stores through + +quadword load and store. + +So you don't want to have little +scalar bits in there + +that you're shuffling around. + +Just deal with it +as a quadword. + +And don't deal with anything +smaller than that. + +So basically the minimum working +sizes, in practice, + +would be 4 by 128 bits wide +and you can split that up + +regularly however you want. + +So to that point I think-- + +here's an example-- + +I want to talk about +a vector class. + +Vector class js usually the +first thing a programmer will + +jump onto when they might want +to make something for games. + +But in real life, it's probably +the most useless + +thing you could ever write. + +It doesn't actually +do anything. + +We have these, we know the +instruction set, it's already + +in quadwords. + +We know the loads and stores, +we've already designed your + +data so it fits properly. + +This doesn't give us anything. + +And it potentially makes +things worse. + +Allowing component access to a +quadword, especially on the + +PPU is ridiculously bad. + +In practice, if you allow +component access, high-level + +programs will use component +access. + +So if you have a vector class +that says get x, get y, + +whatever, somebody somewhere +is going to use it, which + +means the performance of the +whole thing just drops and + +it's impossible to optimize. + +So as a general rule, you pick +your fundamental unit. + +In this case, the 4 by 128 bit +unit that I was talking about + +and you don't define anything +smaller than that. + +Everything is packed into +a unit about that size. + +And yes, in practice there'll +be some wasted space at the + +beginning or end of streams of +data, groups of data, but it + +doesn't make much difference. + +You're going to have that wasted +space if you are-- + +you're going to have much more +than that in wasted space if + +you're using dynamic memory, +for example, which + +when I get to it-- + +I don't recommend +you use either. + +So some things to consider when +you're doing this sort of + +math transformation anyway is, +are you going to do floats, + +double, fixed point? + +I mean, doubles write out. + +There's no point. + +Regardless of the speed on the +SPU of a double, there's no + +value in it for games. + +We have known data, so if we +need to we can renormalize a + +group of around a point and +get into the range of a + +floating point. + +It's a nonissue. + +So there's no reason to waste +the space in a double at all, + +unless it was actually faster, +which it isn't. + +So we don't use it. + +Sort of the only real +problematic thing with the SPU + +floating point is its format +and not supporting + +denormalized numbers becomes +problematic, but again, you + +can work around it by +renormalizing your numbers + +within a known range so that it +won't to get to the point + +where it needs to +denormalize-- + +at least for the work that +you're actually doing. + +Yeah? + +AUDIENCE: [OBSCURED] + +MIKE ACTON: Every program will +write its own vector class. + +And I'm saying that that's +a useless exercise. + +Don't bother doing it. + +Don't use anybody +else's either. + +If you're writing +for the cell-- + +if you're writing in C you +have the SI intrinsics. + +They're already in quadwords, +you can do everything you want + +to do and you're not restricted +by this sort of + +concept of what a vector is. + +If you want to deal with, +especially on the SPU where + +you can freely deal with them +as integers or floats or + +whatever seamlessly without +cost, there's plenty that you + +can do with the floating +point number if you + +treat it as an integer. + +And when on either AltiVec or +the SPU where you can do that + +without cost there's +a huge advantage to + +just doing it straight. + +AUDIENCE: [OBSCURED] + +MIKE ACTON: Well, I'm saying +write it in assembly. + +But if you have to, use +the intrinsics. + +But certainly don't write +a vector class. + +So memory management. + +Static allocations always +prefer the dynamic. + +Basically, general purpose +dynamic memory allocation, + +malloc free, whatever has just +absolutely no place in games. + +We don't have enough unknowns +for that to be valuable. + +We can group our data +by specific types. + +We know basic ranges +of those types. + +The vast majority of the data +is known in advance, it's + +actually burned onto the disk. + +We can actually analyze that. + +So most of our allocations +tend to + +calculate it in advance. + +So you load the level and +oftentimes you just load + +memory in off the disc +into memory and + +then fix up the pointers. + +For things that change during +the runtime, just simple + +hierarchical allocators, block +allocators where you have + +fixed sizes is always the +easiest and best way to go. + +These are known types +of known sizes. + +The key to that is to organize +your data so that's actually a + +workable solution. + +So you don't have these sort of +classes or structures that + +are dynamically sized. + +That you group them in terms +of things that are similar. + +Physics data here and AI data +is separately here in a + +separate array. + +And that way those sort of +chunks of data are similarly + +sized and can be block +allocated without any + +fragmentation issues at all. + +Eventually you'll probably want +to design an allocator. + +Things to consider are +the page sizes. + +That's critically important, you +want to work within a page + +as much as you possibly can. + +So you want to group things, +not necessarily the same + +things, but the things that +will be read together or + +written together within +the same page. + +So you want to have a concept of +the actual page up through + +the system. + +Probably the most common mistake +I see in a block + +allocator, so somebody says-- + +everybody knows what I mean +by block allocator? + +Yeah? + +OK. + +So the most common mistake I see +people make is that they + +do least recently used. + +They just grab the most least +recently used block and use + +that when summoning a request. +That's actually pretty much + +the worst thing you can possibly +do because that's the + +most likely thing +to be called. + +That's the most likely thing to +be out of cache, both out + +of L1 and L2. + +Just the easiest thing you can +do to change that is just use + +most recently used. + +Just go up the other way. + +I mean, there are much more +complicated systems you can + +use, but just that one small +change where you're much more + +likely to get warm data is going +to give you a big boost. + +And again, like I said, use +hierarchies of allocations + +instead of these sort of static +block allocations. + +Instead of trying to have one +general purpose super mega + +allocator that does +everything. + +And again, if it's well planned, +fragmentation is a + +non-issue, it's impossible. + +Cache line, oh, and probably +another important concept to + +keep in mind as you're writing +your allocator is the transfer + +block size of the SPU. + +If you have a 16K block and the +system is aware of fixing + +K blocks then there are plenty +of cases where you don't have + +to keep track of-- in the +system-- the size of things. + +It's just how many blocks, how +many SPU blocks do you have? + +Or what percentage of +SPU blocks you have? + +And that will help you can sort +of compress down your + +memory requirements when you're +referring to blocks and + +memory streams and memory. + +AUDIENCE: About the memory +management for data here, you + +also write overlay managers +for code for the user? + +MIKE ACTON: Well, it basically +amounts to the same thing. + +I mean, the code is just data, +you just load it in and fix up + +the pointers and you're done. + +AUDIENCE: I was just wondering +whether IBM gives you + +embedding -- + +MIKE ACTON: We don't +usse any of the IBM + +systems at all for games. + +I know IBM has an overlay +manager as part of the SDK. + +AUDIENCE: Well, not really. + +It's -- + +MIKE ACTON: Well, they have some +overlay support, right? + +That's not something +we would ever use. + +And in general, I mean, I +guess that's probably an + +interesting question of how-- + +AUDIENCE: So it's +all ground up? + +MIKE ACTON: What's that? + +AUDIENCE: All your development +is ground up? + +MIKE ACTON: Yeah, for +the most part. + +For us, that's definitely +true. + +There are studios that, +especially cross platform + +studios that will take +middleware development and + +just sort of use it +on a high-level. + +But especially when you're +starting a first generation + +platform game, there's virtually +nothing there to use + +because the hardware hasn't been +around long enough for + +anybody else to write +anything either. + +So if you need it, you +write it yourself. + +Plus that's just sort of the +general theme of game + +development. + +It's custom to your situation, +to your data. + +And anything that's general +purpose enough to sell as + +middleware is probably not going +to be fast enough to run + +a triple A title. + +Not always true, but +as a general + +rule, it's pretty valid. + +OK, so-- wait, so how'd +I get here? + +All right, this is next. + +So here's another example +of how the cell + +might affect design. + +So you're writing a collision +detection system. + +It's obvious that you cannot or +should not expect immediate + +results from a collision +detection system, otherwise + +you're going to be sitting and +syncing all the time for one + +result and performance just goes +out the window, you may + +as well just have a +serial program. + +So you want to group results, +you want to group queries and + +you want potentially, for those +queries to be deferred + +so that you can store them, you +can just DMA them out and + +then whatever process needed +then we'll come back and grab + +them later. + +So conceptually that's the +design you want to build into + +a collision detection system, +which then in turn affects the + +high-level design. + +So AI, scripts, any game code +that might have previously + +depended on a result being +immediately available, as in + +they have characters that shoot +rays around the room to + +decide what they're going to +do next or bullets that are + +flying through the air or +whatever, can no longer make + +that assumption. + +So they have to be able to group +up their queries and + +look them up later and +have other work + +to do in the meantime. + +So this is a perfect example +of how you cannot take old + +code and move it to the PS3. + +Because old code, serial code +would have definitely assumed + +that the results were +immediately available because + +honestly, that was the +fastest way to do it. + +So on a separate issue, we have +SPU decomposition for the + +geometry look up. + +So from a high-level you have +your entire scene in the level + +of the world or whatever and you +have the set of queries in + +the case of static-- +did I collide with + +anything in the world? + +Or you have a RAID that, where +does this RAID collide with + +something in the world? + +And so you have this problem of +you have this large sort of + +memory database in main RAM +and you have the smallest + +spew, which obviously cannot +read in the whole database, + +analyze it, and spit +out the result. + +It has to go back and forth +to main RAM in order + +to build its result. + +So the question is how do you +decompose the memory in the + +first place to make +that at least + +somewhat reasonably efficient? + +The first sort of instinct I +think, based on history is + +sort of the traditional scene +graph structures like BSP tree + +or off tree or something +like that. + +Particularly, on the SPU because +if TLB misses that + +becomes really expensive, really +quickly when you're + +basically hitting random +memory on every + +single node on the tree. + +So what you want to do is you +want to make that hierarchy as + +flat as you possibly can. + +If the leafs have to be bigger +that's fine because it turns + +out it's much, much cheaper to +stream in a bigger group of-- + +as much data as you can fit into +the SPU and run through + +it and make your decisions and +spit it back out than it is to + +traverse the hierarchy. + +So basically, the depth of your +hierarchy in your scene + +database is completely +determined by how much data + +you can fit into the +SPU by the maximum + +size of the leaf node. + +The rest of the dep is only +because you don't have any + +other choice. + +You know, And basically the same +thing goes with dynamic + +geometry as you have geometry +moving around in the scene, + +characters moving around +in the scene-- + +they basically need to update +themselves into their own + +database, into their +own leaves and + +they'll do this in groups. + +And then when you query, you +basically want it to query as + +many of those as possible, +as you can + +possibly fit in at once. + +So you could have sort of a +broad faced collision first, + +where you have all of the groups +of characters that are + +potentially maximum +in this leaf, so + +bound and box or whatever. + +So even though you could in +theory, in principle narrow + +that down even more, the cost +for that, the cost for the + +potential memory miss for that +is so high that you just want + +to do a linear search through +as many as you + +possibly can on SPU. + +Does that make sense? + +Procedural graphics-- + +so although we have a GPU on +the PlayStation 3, it does + +turn out that the SPU +is a lot better at + +doing a lot of things. + +Things basically where +you create + +geometry for RSX to render. + +So particle system, dynamic +particle systems. Especially + +where their systems have to +interact with the world in + +some way, which will be much +more expensive on the GPU. + +Sort of a dynamic systems +like cloth. + +Fonts is actually really +interesting because typically + +you'll just see bitmap +fonts in which + +case are just textures. + +But if you have a very complex +user interface then just the + +size of the bitmap becomes +extreme and if you compressed + +them they look terrible, +especially fonts. + +Fonts need to look perfect. + +So if you do do procedural +fonts, for example, two type + +fonts, the cost of rendering +a font actually gets + +significant. + +And in this case, the SPU is +actually a great use for + +rendering a procedural font. + +Rendering textures +is basically the + +same case as font. + +Procedural textures like if you +do noise-based clouds or + +something like that. + +And parametric geometry, it's +like nurbs or subdivision + +services or something like +that, is a perfect + +case for the SPU. + +Is there a question? + +Geometry database, OK. + +First thing scene graphs +are worthless. + +Yeah? + +AUDIENCE: So of those sort of +differnet conceptualized + +paths, are you literally +swapping code in and out of + +the SPUs with the data +many times per frame? + +Or is it more of a static--- + +MIKE ACTON: OK, that's an +excellent question. + +It totally depends. + +I mean, in general through a +game or through, at least a + +particular area of a game the +SPU set up is stable. + +So if we decide you're going to +have this SPU dedicated to + +physics for example, it is very +likely that that SPU is + +stable and it's going to be +dedicated physics, at least + +for some period of time through +the level or through + +the zone or wherever it is. + +Sometimes through +an entire game. + +So there are going to be +elements of that where it's + +sort of a well balanced +problem. + +There's basically no way you're +going to get waste. + +It's always going to be full, +it's always going to be busy. + +Collision detection and physics +are the two things + +that you'll never have +enough CPU to do. + +You can always use more +and more CPU. + +And basically, the rest can +be dynamically scheduled. + +And the question of how to +schedule it, is actually an + +interesting problem. + +It's my opinion that sort of +looking for the universal + +scheduler that solves all +problems and magically makes + +everything work is a +total lost cause. + +You have more than enough data +to work with and in your game + +to decide how to schedule your +SPUs basically, manually. + +And it's just not that +complicated. + +We have six SPUs. + +How to schedule six SPUs is just +not that complicated a + +problem, you could write it +down on a piece of paper. + +OK, so scene graphs are almost +always, universally a complete + +waste time. + +They store way too much data +for no apparent reason. + +Store your databases +independently based on what + +you're actually doing with +them, optimize your data + +separately because you're +accessing it separately. + +The only thing that should be +linking your sort of domain + +object is a key that says all +right, we'll exist in this + +database and the database +and this database. + +But to have this sort of giant +structure that keeps all of + +the data for each element in the +scene is about the poorest + +performing you can imagine for +both cache and TLB and SPU + +because you can't fit it in +individual node on the SPU. + +I think I covered that. + +Here's an interesting example, +so what you want to do is if + +you have the table of queries +that you have-- bunch of + +people over the course of a +frame say I want to know if I + +collided with something. + +And then if you basically make +a pre-sort pass on that and + +basically, spatially sort these +guys together, so let's + +say you have however many +you can fit in a SPU. + +So you have four of these +queries together. + +Although they might be a little +further apart then you + +would hope, you could basically +create a baling box + +through a single query on the +database that's the sum of all + +of them and then as I said, +now you have a linear list + +that you can just stream through +for all of them. + +So even though it's doing more +work for any individual one, + +the overhead is reduced so +significantly that the end + +result is that it's +significantly faster. + +And that's also what I mean by +multiple simultaneous lookups. + +Basically you want to group +queries together, but make + +sure that there's some +advantage to that. + +By spatially pre-sorting them +there is an advantage to that + +because it's more likely +that they will have + +overlap in your queries. + +So game logic. + +Stuff that the cell would +affect in game logic. + +State machines are +a good example. + +If you defer your logic lines +and defer your results, SPUs + +are amazingly perfect for +defining state machines. + +If you expect your logic lines +to be immediately available + +across the entire system, SPU +is absolutely horrid. + +So if you basically write +buffers into your state + +machines or your logic machines +then each SPU can be + +cranking on multiple state +machines at once where all the + +input and all the output lines +are assumed to be deferred and + +it's just an extremely +straightforward process. + +Scripting, so scripting +things like-- + +I don't know, lewis script +or C script or + +something like that. + +I mean, obviously the first +thing to look at is the size + +of the interpreter. + +Will it fit into an +SPU to begin with? + +Another option to consider is, +can it be converted into SPU + +code, either offline +or dynamically? + +Because you'll find that most +off the shelf scripting + +languages are scalar, + +sequential scripting languages. + +So all of a P code within the +scripting language itself + +basically defines +scalar access. + +So not only are you switching +on every byte to every two + +bytes or whatever, so it's sort +of poorly performing code + +from an SPU point of view, but +it's also poorly performing + +code from a memory +point of view. + +So I guess the question is +whether or not you can + +optimize the script itself and +turn turn it into SPU code + +that you can then dynamically +load or come up with a new + +script that's just much more +friendly for the SPUs. + +Another option if you have to +use a single, sort of scalar + +scripting language like lua or +C script or whatever, if you + +can run multiple streams +simultaneously so that while + +you're doing these sort of +individual offline memory + +lookups and reads and writes to +main memory, that once one + +blocks you can start moving +on another one. + +As long as there's no +dependencies between these two + +scripts we should be able +to stream them both + +simultaneously. + +Motion control actually turns +out to be a critical problem + +in games in general that's +often overlooked. + +It's who controls the +motion in the game. + +Is is the AI? + +So is it the controller in +the case of the player? + +I say, push forward, so +the guy moves forward. + +Is that really what +controls it? + +Or is it the physics? + +So all the AI does is say, I +want to move forward, tells + +the physic system I want to move +forward and the physics + +tries to follow it. + +Or is it the animation? + +That you have the animators +actually put translation in + +the animation, so is that +translation the thing that's + +actually driving the motion and +everything else is trying + +to follow it? + +Turns out to be a surprisingly +difficult problem to solve and + +every studio ends up with +their own solution. + +I forget what point I was +making on how the cell + +affected that decision. + +But-- + +AUDIENCE: [OBSCURED] + +MIKE ACTON: I think the point, +probably that I was trying to + +make is that because you want +everything to be deferred + +anyway, then the order does +become a clearer sort of + +winner in that order. + +Where you want the immediate +feedback from the controls, + +the control leads the way. + +You have the physics, which then +follows, perhaps, even a + +frame behind that to say how +that new position is impacted + +by the physical reality +of the world. + +And then potentially a frame +behind that or half a frame + +behind that you have the +animation system, which in + +that case would just be +basically, a visual + +representation of what's +going on rather + +than leading anything. + +It's basically an icon for +what's happening in the + +physics and the AI. + +The limitations of your system +are that it has to be deferred + +and that it has to be +done in groups. + +Basically, some of these sort of +really difficult decisions + +have only one or two +obvious answers. + +All right, well I wanted to dig +into animation a little + +bit, so does anybody have any +questions on anything? + +Any of the sort of the +high-level stuff that I've + +covered up to this point? + +Yeah? + +AUDIENCE: So does the need for +deferral and breaking into + +groups and staging, does this +need break the desire for the + +higher-level programmers to +abstract what's going on at + +the data engine level? + +Or is that not quite +the issue? + +MIKE ACTON: Well, let's +say we get a game + +play programmer, right? + +Fresh out of school, he's +taught in school, C + +plus plus in school. + +Taught to decompose the world +into sort of the main classes + +and that they all communicate +through each other maybe + +through messaging. + +All right, well the first thing +we tell him is that all + +that is complete crap. + +None of that will actually +work in practice. + +So in some sense, yes, there is +a sort of tendency for them + +to want this interface, this +sort of clean abstraction, but + +abstraction doesn't +have any value. + +It doesn't make the game faster, +it doesn't make the + +game cheaper. + +It doesn't make-- + +AUDIENCE: [OBSCURED] + +PROFESSOR: There's a +bit of a religious. + +Let's move on. + +He has a lot of other +interesting things to say. + +And we can get to +that question-- + +AUDIENCE: It sounds like +there's two completely + +different communities involved +in the development. + +There's the engine developers +and there's the higher-level-- + +MIKE ACTON: That's a fair +enough assessment. + +There are different +communities. + +There is a community of the game +play programmers and the + +community of engine +programmers. + +And they have different +priorities and they have + +different experiences. + +So yeah, in that way there +is a division. + +PROFESSOR: I will +let you go on. + +You said you had a lot +of interesting + +information to cover. + +MIKE ACTON: OK. + +AUDIENCE: I can bitch +about that. + +Don't worry. + +MIKE ACTON: So just to get into +animation a little bit. + +Let's start with trying to +build a simple animation + +system and see what problems +come creep up as we're trying + +to implement it on the cell. + +So in the simplest case we +have a set of animation + +channels defined for +a character, which + +is made up of joints. + +We're just talking about sort +of a simple hierarchical + +transformation here. + +And some of those channels +are related. + +So in the case of rotation plus +translation plus scale + +equals any individual joint. + +So the first thing, typically +that you'll have to answer is + +whether or not you want to do +euler or quaternion rotation. + +Now the tendency I guess, +especially for new programmers + +is to go with quaternion. + +They're taught that gimbal +lock is a sort of + +insurmountable problem that +only quaternion solves. + +That's just simply not true. + +I mean, gimbal lock +is completely + +manageable in practice. + +When you're trying to rotate +on three axes and two axes + +rotate 90 degrees apart and +the third axis can't be + +resolved or 180 degrees apart. + +So you can't resolve one +of the axes, right? + +AUDIENCE: [OBSCURED] + +MIKE ACTON: Yeah, it's where +it's impossible to resolve one + +of the axes and that's +the nature of + +euler sort of rotation. + +But sort of a quaternion +rotation completely solves + +that mathematical problem, it's +always resolvable and + +it's not very messy at all. + +I mean, from a sort of C +programmers perspective, it + +looks clean, the math's clean, +everything's clean about it. + +Unfortunately, it doesn't +compress very well at all. + +Where if you used euler +rotation, which basically just + +means that the individual +rotation for every axis. + +So x rotation, y rotation, +z rotation. + +That's much, much more +compressible because each one + +of those axes can be +individually compressed. + +It's very unlikely that you're +always rotating all three + +axes, all the time, especially +in a human character. + +It's much more likely that only +one axis is rotating on + +any one given time and +so that makes it-- + +just without any change, +without any additional + +compression-- it tends to make +it about 1/3 of the size. + +AUDIENCE: [OBSCURED] + +MIKE ACTON: The animation +data. + +So you have this frame of +animation, which is all these + +animation channels, right? + +And then over time you have +these different frames of + +animation, right? + +If you store-- for every joint, +for every rotation you + +store a quaternion over time, +it's hard to compress across + +time because you're basically, +essentially rotating all three + +axes, all the time. + +Well, with-- + +yeah? + +All right. + +So let's say, of course, the +next step is how do we store + +the actual rotation itself? + +Do we store it in cloth, double, +half precision, fixed + +point precision? + +Probably the national tendency +at this point would be to + +store it in a floating point +number, but if you look at the + +actual range of rotation, which +is extremely limited on + +a character, on any particular +joint there are very few + +joints that would even +rotate 180 degrees. + +So a floating point +is overkill, by a + +large margin on rotation-- + +for the range. + +For the precision, however +it's fairly good. + +Especially if you're doing very +small rotations over a + +long period of time. + +So probably a more balanced +approach would be to go with a + +16 bit floating point from a +half format where you keep + +most of the precision, but +you reduce the range + +significantly. + +There's also the potential for +going with an 8 bit floating + +point format depending +on the kind of + +animation that you're doing. + +And I'll probably have this on +another slide, but it really + +depends on how close-- + +how compressible a joint is +depends on how close to the + +root it is. + +The further away from the root +the less it matters. + +So the joint at your fingertip, +you can compress a + +whole lot more because it +doesn't matter as much, it's + +not going to affect +anything else. + +Where a joint at the actual +root, the smallest change in + +motion will affect the entire +system in animation and will + +make it virtually impossible for +you to line up animations + +with each other, so that that +particular joint needs to be + +nearly perfect. + +And how do you store rotation? + +Do you store them in degrees, +radians, or normalized? + +I have seen people store +them in degrees. + +I don't understand why you +would ever do that. + +It's just adding math +to the problem. + +Radians is perfectly fine if +you're using off the shelf + +trigonometric functions- +tan, sine whatever. + +But typically, if you're going +to optimize those functions + +yourself anyway, it's going to +be much more effective go with + +a normalized rotational value. + +So basically between +zero and 1. + +Makes it a lot easier to do +tricks based on the circle. + +Basically you can just take the +fractional value and just + +deal with that. + +So normalized rotation is +generally the way to go and + +normalizing a half precision is +probably the even bet for + +how you would store. + +So looking at what we need to +fit into an SPU if we're going + +to running to an end machine. + +Yeah? + +AUDIENCE: You talked a lot about +compressing because of + +the way it's impacting data, +what's the key driver of that? + +MIKE ACTON: The SPU has +very little space. + +AUDIENCE: OK, so it's just +the amount of space. + +MIKE ACTON: Yeah, well OK. + +There's two factors really, +in all honesty. + +So starting with the SPU. + +That you have to be able +to work through + +this data on the SPU. + +But you also have the +DMA transfer itself. + +The SPU can actually calculate +really, really fast, right? + +I mean, that's the +whole point. + +So if you can transfer less +data, burn through it a little + +bit to expand it, it's +actually a huge win. + +And on top of that we have a +big, big game and only 256 + +megs of main ram. + +And the amount of geometry that +people require from a + +current generation game or +next generation game has + +scaled up way more than the +amount of memory we've been + +given, so we've only been given +eight times as much + +memory as we had in the +previous generation. + +People expect significantly more +than eight times as much + +geometry on the screen and +where do we store that? + +We have the Blu-Ray, we can't +be streaming everything off + +the disc all the time, which +is to another point. + +You have 40 gigs of data +on your disc, but + +only 256 megs of RAM. + +So there's this sort of a +series of compression, + +decompression to keep +everything-- + +basically, think of RAM +as your L3 cache. + +So we look at what we want +to store on an SPU. + +Basically, the goal of this is +we want to get an entire + +animation for a particular +skeleton on an SPU so that we + +can transform the skeleton +and output the + +resulting joint data. + +So let's look at how big +that would have to be. + +So first we start with the basic +nine channels per joint. + +That's not assuming and again, +you'd probably have additional + +channels, like foot step +channels and sound channels + +and other sort of animation +channels to help + +actually make a game. + +In this case, we just want +to animate the character. + +So we have rotation times 3, +translations times 3, and + +scales times 3. + +So the first thing to drop and +this will cover, this will + +reduce your data by 70%, is +all the uniform channels. + +So any data that doesn't +actually change across the + +entire length of +the animation. + +It may not be zero, but it could +be just one thing, one + +value that doesn't +change across + +length of the animation. + +So you pull all the uniform +channels out. + +And most things that's going to +be scale, for example, most + +joints don't scale. + +Although occasionally they do. + +And translation, in a human our +joints don't translate. + +However, when you actually +animate a character in order + +to get particular effects, in +order to make it look more + +human you do end up needing +to translate joints. + +So we can reduce, but in order +to that we need to build a + +map, basically, a table of +these uniform channels. + +So now we know this table of +uniform channels has to be + +stored in the SPU along with +now the remaining actual + +animation data. + +Of course, multiplied by +the number of joints. + +So now we have what +is essentially + +raw animation data. + +So for the sake of argument, +let's say the animation data + +has been baked out by +Maya or whatever + +at 30 frames a second. + +We've pulled out the uniform +data, so now for the joints + +that do move we have these +curves over time of the entire + +length of the animation. + +The problem is if that animation +is 10 seconds long, + +it's now way too big to fit in +the SPU by a large margin. + +So how do we sort of compress +it down so that it + +actually will fit? + +Again, just first of all, the +easiest thing to do to start + +with is just do simple curve +fitting to get rid of the + +things that don't need to be +there that you can easily + +calculate out. + +And again, the closer that you +are to the root, the tighter + +that fits need to be. + +Conversely, the further away you +are from the root, you can + +loosen up the restrictions a +little bit and have a little + +bit looser fit on the +curve and compress + +a little bit more. + +So if you're doing a curve +fitting with the simple + +spline, basically you have to +store your time values in the + +places that were calculated. + +Part of the problem is now you +have sort of these individual + +scalars with time can be +randomly spread throughout the + +entire animation. + +So any point where there's +basically a knot in the curve, + +there's a time value. + +And none of these knots are +going to line up with each + +other in any of these +animation channels. + +So in principle, if you wanted +to code this you would have to + +basically say, what is time +right now and loop through + +each of these scalar values, +find out where time is, + +calculate the postition +on the curve and then + +spit out the result. + +So one, you still have to have +the unlimited length of data + +and two, you're looping through +scalar values on the + +SPU, which is really +actually, horrible. + +So we want to find a way +to solve that problem. + +Probably the most trivial +solution is + +just do spline segemnts. + +You lose some compressibility, +but it solves the problem. + +Basically you split up the +spline into say, sections of + +16 knots and you just do that. + +And in order to do that you just +need a table, you need to + +add a table that says what the +range of time are in each of + +those groups of 16 knots +for every channel. + +So when you're going to +transform the animation, first + +you load this table in, you say, +what's my time right now + +at time, t? + +You go and say which blocks, +which segments of the spline + +you need to load in for each +channel, you load those in. + +So now you have basically one +section of the spline, which + +is too big probably for the +current t, but it covers what + +t you're actually in. + +So one block of spline for +every single channel. + +So the advantage of this, now +that the spline is sorted into + +sections is that rather than +having all the spline data + +stored, sort of linearly, you +can now reorder the blocks so + +that the spline data from +different channels is actually + +tiled next to each other. + +So that when you actually go +to do a load it's much more + +likely because you know you're +going to be requesting all + +these channel at once and all +on the same time, t, you can + +find a more or less, optimal +ordering that will allow more + +of these group things to be +grouped in the same cache or + +at least the same page. + +And the advantage of course +again, is now the length of + +animation makes absolutely +no difference at all. + +The disadvantage is its less +compressible because you can + +only basically compress this one +section of the curve, but + +a huge advantage is it solves +the scalar loop problem. + +So now you can take four of +these scalar values all with a + +fixed known number of knots in +it and just loop through all + +of the knots. + +In principle you could search +through and find a minimum + +number of knots to look through +for each one of the + +scalars, but in practice it's +much faster just to loop + +through all four simultaneously +for all 16 + +knots and just throw away the +results that are invalid as + +you're going through it. + +That way you can use the +SPU instruction set. + +You can load quadwords, store +quadwords, and do everything + +in the minimum single +loop, which you + +can completely unroll. + +Does anybody have the time? + +PROFESSOR: It's [OBSCURED] + +MIKE ACTON: So I'm OK. + +PROFESSOR: [OBSCURED] + +MIKE ACTON: Yeah? + +AUDIENCE: In + +context do you make like +rendering the animation or it + +seems like there would be a blow +to whatever you're doing + +on the SPUs. + +MIKE ACTON: Basically the SPUs +are taking this channel + +animation data and baking it +out into-- well, in the + +easiest case baking +it out into a 4 by + +4 matrix per joint. + +AUDIENCE: So the output +time's much bigger + +than the input time? + +I mean, you're compressing +the input by animation? + +MIKE ACTON: No, the output size +is significant, but it's + +much smaller. + +PROFESSOR: [OBSCURED] + +AUDIENCE: So the animation +data it's [OBSCURED] + +[INTERPOSING VOICES] + +MIKE ACTON: No. + +I was just outputting the +joint information. + +PROFESSOR: [OBSCURED] + +MIKE ACTON: Independently we +have this skimming problem. + +Independently there's +a rendering problem. + +This is just baking animation. + +This is purely animation +channel problem. + +PROFESSOR: [OBSCURED] + +MIKE ACTON: OK, I'm just going +to skip through this because + +this could take a long +time to talk about. + +Basically, what I wanted to say +here was let's take the + +next step with animation, +let's add + +some dynamic support. + +The easiest thing to do is just +create a second uniform + +data table that you then +blend with the first + +one and that one. + +In principle, is basically all +of the channels and then now a + +game play programmer can go and + +individually set any of those. + +So they can tweak the head or +tweak the elbow or whatever. + +And that's definitely +compressible because it's very + +unlikely thet're going to be +moving all the joints at once. + +You can create a secondary map +that says, this is the number + +of joints that are dynamic, this +is how they map to the + +uniform values. + +But then once you add any kind +of dynamic support, you have + +now complicated the problem +significantly. + +Because now in reality, what +you need are constraints. + +You need to be able to have a +limit to how high the head can + +move because what's going to +happen is although you could + +just say the head could only +move so much, if that movement + +is algorithmic, so let's +say follow a + +character or whatever-- + +it is going to go outside +of reasonable + +constraints really quickly. + +So it's much cleaner and simpler +to support that on the + +engine side, so basically define +constraints for the + +joints and then let the +high-level code point + +wherever they want. + +AUDIENCE: [OBSCURED] + +MIKE ACTON: Yeah. + +Yeah, you can have max change +over time so it only can move + +so fast. The max range of +motion, the max acceleration + +is actually a much harder +problem because it implies + +that you need to store the +change over time, which we're + +not actually storing. + +Which would probably blow +our memory on the SPU. + +So as far as impacting +animation, I would immediately + +throw out max acceleration if an +animator were to come to me + +and say, this is a feature +that I wanted. + +I would say, it's unlikely +because it's unlikely we can + +fit it on the SPU. + +Whereas, on the PC, it might +be a different story. + +And blending information, +how you blend + +these things together. + +What's that? + +AUDIENCE: [OBSCURED] + +MIKE ACTON: OK. + +So as far as mixing, there's +plenty of additional problems + +in mixing animation. + +Phase matching, so for example, +you have a running + +and a walk. + +Basically all that means is if +you were going to blend from a + +run to a walk you kind of want +to blend in basically the + +essentially same leg position. + +Because if you just blend from +the middle of an animation to + +the beginning of the animation, +it's unlikely the + +legs are going to match and for +the transition time you're + +going to see the scissoring +of the legs. + +Which you see that in plenty +of games, but especially in + +next generation, especially +as characters look more + +complicated they are expected +to act more complicated. + +Transitions handling either +programmatic transitions + +between animations, so we have +an animation that's standing + +and animation that's crouching +and with constraints, move + +them down; or artist +driven animated + +transitions and/or both. + +Translation matching +is actually + +an interesting problem. + +So you have an animation that's +running and you have an + +animation that's walking. + +They both translate obviously, +at different speeds, + +nonlinearly and you want to +slowly run down into a walk, + +but you have to match these sort +of nonlinear translations + +as his feet are stepping +onto the ground. + +Turns out to be a really +difficult problem to get + +perfectly right, especially if +you have eye key on the feet + +where he's walking on the ground +or maybe walking uphill + +or downhill and the translation +is being affected + +by the world. + +In a lot of cases you'll see +people pretty much just ignore + +this problem. + +But it is something to consider +going forward and + +this is something that we would +consider how to solve, + +regardless of whether or +not we could get it in. + +As far as actually rendering +the geometry goes, you now + +have your sort of matrices +of joints and you have-- + +let's say you want to send those +to the GPU along with + +the geometry to skin +and render. + +Now the question is, do +you single or double + +buffer those joints? + +Because right now basically, the +GPU can be reading these + +joints in parallel +to when you're + +actually outputting them. + +So the traditional approach or +the easiest approach is just + +to double buffer the joints. + +So just output into a different +buffer that the R6 + +is reading from. + +It's one frame or half a frame +behind, doesn't much matter. + +But it also doubles now the +space of your joints. + +One advantage that games have +is that a frame is a well + +defined element in the games. + +We know what needs to happen +across the course of a frame. + +So these characters need to be +rendered, the collisions of + +this background needs +to happen, physics + +need to happen here. + +So you can within a frame, set +it up so that the update from + +the SPUs and the read from the +GPU can never overlap. + +Even without any kind of +synchronization or lock, it + +can be a well known fact that +it's impossible for these two + +things because there's actually +something in the + +middle happening that has its +own synchronization primitive. + +That will allow you to do single +buffering of the data. + +But it does require +more organization. + +Especially if you're doing it +on more than just one case. + +So you have all these things +that you want single buffered, + +so you need to organize them +within the frames so they're + +never updating and reading +at the same time. + +So I'll make this the last +point I'll make. + +Optimization, one of the things +that you'll hear, save + +optimization till the end. + +My point here being is if you +save optimization till the + +end, you don't know how to +do it because you haven't + +actually practiced it. + +If you haven't practiced it +you don't know what to do. + +So it will take much longer. + +You should always be optimizing +in order to + +understand, when it actually +counts, what to do. + +And the fact that real +optimization does impact the + +design all the way up. + +Optimization of the hardware +impacts how an engine is + +designed to be fast does impact +the data, it impacts + +how game play needs to be +written, high-level code needs + +to be called. + +So if you save optimization till +last, what you're doing + +is completely limiting what +you can optimize. + +And the idea that it's the root +of all evil certainly + +didn't come from a game +developer, I have to say. + +Anyway, that's it. + +I hope that was helpful. + +PROFESSOR: Any questions? + +I think it's very interesting +because there is a lot of + +things you learn at MIT. + +Forget everything you learned +so I think there's a very + +interesting perspective in there +and for some of us it's + +kind of hard to even digest a +little bit, but Question? + +AUDIENCE: Call of Duty 3 came +out on the Xbox and on the + +PS3, is Call of Duty 3 on the +PS3 just running on the GPU + +then or is it-- + +MIKE ACTON: No, it's very +likely using the SPUs. + +I mean, I don't know. + +I haven't looked at the source +code, but I suspect that it's + +using the SPUs. + +How efficiently it's +using them is an + +entirely different question. + +But it's easy to take the most +trivial things right, say you + +do hot spot analysis on your +sequential code and say, OK, + +well I can grab this section of +thing and put it on the SPU + +right and just the heaviest +hitters and + +put them on the SPU. + +That's pretty easy to do. + +It's taking it to the next level +though, and to really + +have sort of the next +gen of game-- + +now there's nowhere +to go from there. + +There's nowhere to go from that +analysis, you've already + +sort of hit the limit of what +you can do with that. + +It has to be redesigned. + +So I don't know what they're +doing honestly and certainly + +I'm being recorded so-- + +yeah? + +AUDIENCE: You guys have shipped +a game, on the PS3? + +MIKE ACTON: Yeah, it +was on action list. + +AUDIENCE: OK, so that was +more like the [OBSCURED] + +games and whatever You seem to +talk a lot about all these + +things you've had to redo. + +What else is there-- + +games look better as a console +was built on, what else is + +there that you guys plan on +changing as far as working + +with the cell processor, +or do you think + +you've got it all ready? + +MIKE ACTON: Oh, no. + +There's plenty of work. + +There's plenty more +to be optimized. + +It's down to cost in scheduling +those things. + +I mean, we have a team of +people who now really + +understand the platform and +whereas a lot of what went + +into previous titles was mixed +with learning curve. + +So there's definitely a +potential for going back and + +improving things and making +things better. + +That's what a cycle of game +development is all about. + +I mean, games at the end of the +lifetime of PlayStation 3 + +will look significantly better +than release titles. + +That's the way it always is. + +AUDIENCE: The head of Sony +computer and gaming said that + +PS3 pretty soon would +be customizable. + +You're be able to get different + +amounts of RAM and whatnot. + +MIKE ACTON: Well, I think in +that case he was talking + +specifically about a PS3 based, +like Tivo kind of weird + +media thing, which has nothing +to do with us. + +AUDIENCE: [OBSCURED] + +MIKE ACTON: We're not stuck. + +That's what we have. I mean, +I don't see it as stuck. + +I would much rather have the-- + +I mean, that's what console +development is about, really. + +We have a machine, we have a set +of limitations of it and + +we can push that machine over +the lifetime of the platform. + +If it changes out from under us, +it becomes PC development. + +AUDIENCE: Are you allowed +to use the + +seven SPUs or are you-- + +[OBSCURED] + +PROFESSOR: [OBSCURED] + +MIKE ACTON: I don't know how +much I can answer this just + +from NDA point-of-view. + +But let's say hypothetically, +there magically became more + +SPUs on the PS3, right? + +Probably nothing would happen. + +The game has to be optimized +for the minimum case, so + +nothing would change. + +Anything else? + +Yeah? + +AUDIENCE: So what's the +development life cycle like + +for the engine part +of the game. + +And I don't assume you start by +prototyping in higher-level + +mechanisms. Then you'll +completely miss the design for + +performance aspects of it. + +How do you build up from +empty [OBSCURED] + +MIKE ACTON: No, you don't +start with an empty. + +That's the perspective +difference. + +You don't start with code, +code's not important. + +Start with the data. + +You sit down with an artist +and they say, what + +do you want to do? + +And then you look at the data. + +What does that data look like? + +What does this animation +data look like? + +PROFESSOR: Data size matters. + +[OBSCURED] + +MIKE ACTON: Right. + +We have to figure out how +to make it smaller. + +But it all starts +with the data. + +It all starts with that concept +of what do we want to + +see on the screen? + +What do we even want to +hear on the speakers? + +What kind of effects +do we want. + +And actually look at that from +the perspective of the content + +creator and what they're +generating and what we can do + +with that data. + +Because game development is just +this black box between + +the artists and the screen. + +We're providing a transformation +engine that + +takes the vision of the +designers and the artists and + +just transforming it and +spitting it on to screen. + +So where you really need +to start is with the + +source of the data. + +AUDIENCE: You've been doing game +developoment for 11 years + +now is what you said. + +Have you had a favorite +platform + +and a nightmare platform? + +MIKE ACTON: I've been pretty +much with the PlayStation + +platform since there was a +PlayStation platform and I + +don't know, it's hard to get +perspective because you're + +getting it and you always really +love plarform you're + +working on. + +So it's hard. + +I mean, it's hard to +get perspective. + +In the program where I am today +is not the same program + +where I was 10 years ago. + +Personally, right now my +favorite plarform is PS3. + +PROFESSOR: So when put it in +perspective, there are already + +some platforms that on the first +time round, [COUGHING], + +it's like cost of development. + +So one platform that as time +goes we have [OBSCURED] + +MIKE ACTON: Well, like with the +PS3, some of the things + +that I like about the PS3, which +is sort of a different + +question are the fact that the +cell is much more public than + +any other platform +has ever been. + +With IBM's documentation, with +Toshiba's support and Sony + +support, I've never had a +platform where I can get up on + +a website and actually talk +about it outside of NDA. + +And that for me is an +amazing change. + +Where I can go and talk to other +people-- exactly like + +this group here- that have +used the same exact + +platform I've used. + +That's never been able +to happen before. + +Even on PS2, for quite a long +part of the lifespan, even + +though there was a Linux +eventually on the PS2, + +virtually everything was covered +by NDA because there + +was no independent release +of information. + +So that's one of the great +things about PS3 is the public + +availability of cell. + +PROFESSOR: Thank you very much +for coming all the way from + +California and giving +us some insight. \ No newline at end of file diff --git a/Sygq1e0xWnM.txt b/Sygq1e0xWnM.txt new file mode 100644 index 0000000000000000000000000000000000000000..e1e0dd7fc0a4a462578eef0eb8aae6377abd40c8 --- /dev/null +++ b/Sygq1e0xWnM.txt @@ -0,0 +1,3211 @@ +-- shortest paths. +This is the finale. + +Hopefully it was worth waiting +for. + +Remind you there's a quiz +coming up soon, + +you should be studying for it. +There's no problem set due at + +the same time as the quiz +because you should be studying + +now. +It's a take-home exam. + +It's required that you come to +class on Monday. + +Of course, you'll all come, +but everyone watching at home + +should also come next Monday to +get the quiz. + +It's the required lecture. +So, we need a bit of a recap in + +the trilogy so far. +So, the last two lectures, + +the last two episodes, +or about single source shortest + +paths. +So, we wanted to find the + +shortest path from a source +vertex to every other vertex. + +And, we saw a few algorithms +for this. + +Here's some recap. +We saw in the unweighted case, + +that was sort of the easiest +where all the edge weights were + +one. +Then we could use breadth first + +search. +And this costs what we call + +linear time in the graph world, +the number of vertices plus the + +number of edges. +The next simplest case, + +perhaps, is nonnegative edge +weights. + +And in that case, +what algorithm do we use? + +Dijkstra, all right, +everyone's awake. + +Several answers at once, +great. + +So this takes almost linear +time if you use a good heap + +structure, so, +V log V plus E. + +And, in the general case, +general weights, + +we would use Bellman-Ford which +you saw. + +And that costs VE, +good, OK, which is quite a bit + +worse. +This is ignoring log factors. + +Dijkstra is basically linear +time, Bellman-Ford you're + +quadratic if you have a +connected graph. + +So, in the sparse case, +when E is order V, + +this is about linear. +This is about quadratic. + +In the dense case, +when E is about V^2, + +this is quadratic, +and this is cubic. + +So, Dijkstra and Bellman-Ford +are separated by about an order + +of V factor, which is pretty +bad. + +OK, but that's the best we know +how to do for single source + +shortest paths, +negative edge weights, + +Bellman-Ford is the best. +We also saw in recitation the + +case of a DAG. +And there, what do you do? + +Topological sort, +yeah. + +So, you can do a topological +sort to get an ordering on the + +vertices. +That you run Bellman-Ford, + +one round. +This is one way to think of + +what's going on. +You run Bellman-Ford in the + +order given by the topological +sort, which is once, + +and you get a linear time +algorithm. + +So, DAG is another case where +we know how to do well even with + +weights. +Unweighted, we can also do + +linear time. +But most of the time, + +though, will be, +so you should keep these in + +mind in the quiz. +When you get a shortest path + +problem, or what you end up +determining is the shortest path + +problem, think about what's the +best algorithm you can use in + +that case? +OK, so that's single source + +shortest paths. +And so, in our evolution of the + +Death Star, initially it was +just nonnegative edge weights. + +Then we got negative edge +weights. + +Today, the Death Star +challenges us with all pair + +shortest paths, +where we want to know the + +shortest path weight between +every pair of vertices. + +OK, so let's get some quick +results. + +What could we do with this +case? + +So, for example, +suppose I have an unweighted + +graph. +Any suggestions of how I should + +compute all pair shortest paths? +Between every pair of vertices, + +I want to know the shortest +path weight. + +BFS, a couple more words? +Yeah? + +Right, BFS V times. +OK, I'll say V times BFS, + +OK? +So, the running time would be + +V^2 plus V times E, +yeah, which is assuming your + +graph is connected, +V times E. + +OK, good. +That's probably about the best + +algorithm we know for unweighted +graphs. + +So, a lot of these are going to +sort of be the obvious answer. + +You take your single source +algorithm, you run it V times. + +That's the best you can do, +OK, or the best we know how to + +do. +This is not so bad. + +This is like one iteration of +Bellman-Ford, + +for comparison. +We definitely need at least, + +like, V^2 time, +because the size of the output + +is V^2, shortest path weight we +have to compute. + +So, this is not perfect, +but pretty good. + +And we are not going to improve +on that. + +So, nonnegative edge weights: +the natural thing to do is to + +run Dijkstra V times, +OK, no big surprise. + +And the running time of that +is, well, V times E again, + +plus V^2, log V, +which is also not too bad. + +I mean, it's basically the same +as running BFS. + +And then, there's the log +factor. + +If you ignore the log factor, +this is the dominant term. + +And, I mean, +this had an [added?] V^2 as + +well. +So, these are both pretty good. + +I mean, this is kind of neat. +Essentially, + +the time it takes to run one +Bellman-Ford plus a log factor, + +you can compute all pair +shortest paths if you have + +nonnegative edge weights. +So, I mean, comparing all pairs + +to signal source, +this seems a lot better, + +except we can only handle +nonnegative edge weights. + +OK, so now let's think about +the general case. + +Well, this is the focus of +today, and here's where we can + +actually make an improvement. +So the obvious thing is V times + +Bellman-Ford, +which would cost V^2 times E. + +And that's pretty pitiful, +and we're going to try to + +improve that to something closer +to that nonnegative edge weight + +bound. +So it turns out, + +here, we can actually make an +improvement whereas in these + +special cases, +we really can't do much better. + +OK, I don't have a good +intuition why, + +but it's the case. +So, we'll cover something like + +three algorithms today for this +problem. + +The last one will be the best, +but along the way we'll see + +some nice connections between +shortest paths and dynamic + +programming, which we haven't +really seen yet. + +We've seen shortest path, +and applying greedy algorithms + +to it, but today will actually +do dynamic programming. + +The intuition is that with all +pair shortest paths, + +there's more potential +subproblem reuse. + +We've got to compute the +shortest path from x to y for + +all x and y. +Maybe we can reuse those + +shortest paths in computing +other shortest paths. + +OK, there's a bit more +reusability, let's say. + +OK, let me quickly define all +pair shortest paths formally, + +because we're going to change +our notation slightly. + +It's because we care about all +pairs. + +So, as usual, +the input is directed graph, + +so, vertices and edges. +We're going to say that the + +vertices are labeled one to n +for convenience because with all + +pairs, we're going to think of +things more as an n by n matrix + +instead of edges in some sense +because it doesn't help to think + +any more in terms of adjacency +lists. + +And, you have edge weights as +usual. + +This is what makes it +interesting. + +Some of them are going to be +negative. + +So, w maps to every real +number, and the target output is + +a shortest path matrix. +So, this is now an n by n + +matrix. +So, n is just the number of + +vertices of shortest path +weights. + +So, delta of i, +j is the shortest path weight + +from i to j for all pairs of +vertices. + +So this, you could represent as +an n by n matrix in particular. + +OK, so now let's start doing +algorithms. + +So, we have this very simple +algorithm, V times Bellman-Ford, + +V^2 times E, +and just for comparison's sake, + +I'm going to say, +let me rewrite that, + +V times Bellman-Ford gives us +this running time of V^2 E, + +and I'm going to think about +the case where, + +let's just say the graph is +dense, meeting that the number + +of edges is quadratic, +and the number of vertices. + +So in that case, +this will take V^4 time, + +which is pretty slow. +We'd like to do better. + +So, first goal would just be to +beat V^4, V hypercubed, + +I guess. +OK, and we are going to use + +dynamic programming to do that. +Or at least that's what the + +motivation will come from. +It will take us a while before + +we can even beat V^4, +which is maybe a bit pathetic, + +but it takes some clever +insights, let's say. + +OK, so I'm going to introduce a +bit more notation for this + +graph. +So, I'm going to think about + +the weighted adjacency matrix. +So, I don't think we've really + +seen this in lecture before, +although I think it's in the + +appendix. +What that means, + +so normally adjacency matrix is +like one if there's an edge, + +and zero if there isn't. +And this is in a digraph, + +so you have to be a little bit +careful. + +Here, these values, +the entries in the matrix, + +are going to be the weights of +the edges. + +OK, this is this if ij is an +edge. + +So, if ij is an edge in the +graph, and it's going to be + +infinity if there is no edge. +OK, in terms of shortest paths, + +this is a more useful way to +represent the graph. + +All right, and so this includes +everything that we need from + +here. +And now we just have to think + +about it as a matrix. +Matrices will be a useful tool + +in a little while. +OK, so now I'm going to define + +some sub problems. +And, there's different ways + +that you could define what's +going on in the shortest paths + +problem. +OK, the natural thing is I want + +to go from vertex i to vertex j. +What's the shortest path? + +OK, we need to refine the sub +problems a little but more than + +that. +Not surprising. + +And if you think about my +analogy to Bellman-Ford, + +what Bellman-Ford does is it +tries to build longer and longer + +shortest paths. +But here, length is in terms of + +the number of edges. +So, first, it builds shortest + +paths of length one. +We've proven the first round it + +does that. +The second round, + +it provides all shortest paths +of length two, + +of count two, +and so on. + +We'd like to do that sort of +analogously, and try to reuse + +things a little bit more. +So, I'm going to say d_ij^(m) + +is the weight of the shortest +path from i to j with some + +restriction involving m. +So: shortest path from i to j + +using at most m edges. +OK, for example, + +if m is zero, +then we don't have to really + +think very hard to find all +shortest paths of length zero. + +OK, they use zero edges, +I should say. + +So, Bellman-Ford sort of tells +us how to go from m to m plus + +one. +So, let's just figure that out. + +So one thing we know from the +Bellman-Ford analysis is if we + +look at d_ij^(m-1), +we know that in some sense the + +longest shortest path of +relevance, unless you have + +negative weight cycle, +the longest shortest path of + +relevance is when m equals n +minus one because that's the + +longest simple path you can +have. + +So, this should be a shortest +path weight from i to j, + +and it would be no matter what +larger value you put in the + +superscript. +This should be delta of i comma + +j if there's no negative weight +cycles. + +OK, so this feels good for +dynamic programming. + +This will give us the answer if +we can compute this for all m. + +Then we'll have the shortest +path weights in particular. + +We need a way to detect +negative weight cycles, + +but let's not worry about that +too much for now. + +There are negative weights, +but let's just assume for now + +there's no negative weight +cycles. + +OK, and we get a recursion +recurrence. + +And the base case is when m +equals zero. + +This is pretty easy. +They have the same vertices, + +the weight of zero, +and otherwise it's infinity. + +OK, and then the actual +recursion is for m. + +OK, if I got this right, +this is a pretty easy, + +intuitive recursion for +d_ij^(m) is a min of smaller + +things in terms of n minus one. +I'll just show the picture, + +and then the proof of that +claim should be obvious. + +So, this is proof by picture. +So, we have on the one hand, + +I over here, +and j over here. + +We want to know the shortest +path from i to j. + +And, we want to use, +at most, m edges. + +So, the idea is, +well, you could use m minus one + +edges to get somewhere. +So this is, at most, + +m minus one edges, +some other place, + +and we'll call it k. +So this is a candidate for k. + +And then you could take the +edge directly from k to j. + +So, this costs A_k^j, +and this costs DIK m minus one. + +OK, and that's a candidate path +of length that uses, + +at most, m edges from I to j. +And this is essentially just + +considering all of them. +OK, so there's sort of many + +paths we are considering. +All of these are candidate + +values of k. +We are taking them in over all + +k as intermediate nodes, +whatever. + +So there they are. +We take the best such path. + +That should encompass all +shortest paths. + +And this is essentially sort of +what Bellman-Ford is doing, + +although not exactly. +We also sort of want to think + +about, well, what if I just go +directly with, + +say, m minus one edges? +What if there is no edge here + +that I want to use, +in some sense? + +Well, we always think about +there being, and the way the A's + +are defined, there's always this +zero weight edge to yourself. + +So, you could just take a path +that's shorter, + +go from d i to j, +and j is a particular value of + +k that we might consider, +and then take a zero weight + +edge at the end from A and jj. +OK, so this really encompasses + +everything. +So that's a pretty trivial + +claim. +OK, now once we have such a + +recursion, we get a dynamic +program. + +I mean, there, +this is it in some sense. + +It's written recursively. +You can write a bottom up. + +And I would like to write it +bottom up it little bit because + +while it doesn't look like it, +this is a relaxation. + +This is yet another relaxation +algorithm. + +So, I'll give you, +so, this is sort of the + +algorithm. +This is not a very interesting + +algorithm. +So, you don't have to write it + +all down if you don't feel like +it. + +It's probably not even in the +book. + +This is just an intermediate +step. + +So, we loop over all m. +That's sort of the outermost + +thing to do. +I want to build longer and + +longer paths, +and this vaguely corresponds to + +Bellman-Ford, +although it's actually worse + +than Bellman-Ford. +But hey, what the heck? + +It's a stepping stone. +OK, then for all i and j, + +and then we want to compute +this min. + +So, we'll just loop over all k, +and relax. + +And, here's where we're +actually computing the min. + +And, it's a relaxation, +is the point. + +This is our good friend, +the relaxation step, + +relaxing edge. +Well, it's not, + +yeah. +I guess we're relaxing edge kj, + +or something, +except we don't have the same + +clear notion. +I mean, it's a particular thing + +that we're relaxing. +It's not just a single edge + +because we don't have a single +source anymore. + +It's now relative to source I, +we are relaxing the edge kj, + +something like that. +But this is clearly a + +relaxation. +We are just making the triangle + +inequality true if it wasn't +before. + +The tribal inequality has got +to hold between all pairs. + +And that's just implementing +this min, right? + +You're taking d ij. +You take the min of what it was + +before in some sense. +That was one of the + +possibilities we considered when +we looked at the zero weight + +edge. +We say, well, + +or you could go from i to some +k in some way that we knew how + +to before, and then add on the +edge, and check whether that's + +better if it's better, +set our current estimate to + +that. +And, you do this for all k. + +In particular, +you might actually compute + +something smaller than this min +because I didn't put + +superscripts up here. +But that's just making paths + +even better. +OK, so you have to argue that + +relaxation is always a good +thing to do. + +So, by not putting +superscripts, + +maybe I do some more +relaxation, but more relaxation + +never hurts us. +You can still argue correctness + +using this claim. +So, it's not quite the direct + +implementation, +but there you go, + +dynamic programming algorithm. +The main reason I'll write it + +down: so you see that it's a +relaxation, and you see the + +running time is n^4, +OK, which is certainly no + +better than Bellman-Ford. +Bellman-Ford was n^4 even in + +the dense case, +and it's a little better in the + +sparse case. +So: not doing so great. + +But it's a start. +OK, it gets our dynamic + +programming minds thinking. +And, we'll get a better dynamic + +program in a moment. +But first, there's actually + +something useful we can do with +this formulation, + +and I guess I'll ask, +but I'll be really impressed if + +anyone can see. +Does this formula look like + +anything else that you've seen +in any context, + +mathematical or algorithmic? +Have you seen that recurrence + +anywhere else? +OK, not exactly as stated, + +but similar. +I'm sure if you thought about + +it for awhile, +you could come up with it. + +Any answers? +I didn't think you would be + +very intuitive, +but the answer is matrix + +multiplication. +And it may now be obvious to + +you, or it may not. +You have to think with the + +right quirky mind. +Then it's obvious that it's + +matrix multiplication. +Remember, matrix + +multiplication, +we have A, B, + +and C. +They're all n by n matrices. + +And, we want to compute C +equals A times B. + +And what that meant was, +well, c_ij was a sum over all k + +of a_ik times b_kj. +All right, that was our + +definition of matrix +multiplication. + +And that formula looks kind of +like this one. + +I mean, notice the subscripts: +ik and kj. + +Now, the operators are a little +different. + +Here, we're multiplying the +inside things and adding them + +all together. +There, we're adding the inside + +things and taking them in. +But other than that, + +it's the same. +OK, weird, but here we go. + +So, the connection to shortest +paths is you replace these + +operators. +So, let's take matrix + +multiplication and replace, +what should I do first, + +plus this thing with min. +So, why not just change the + +operators, replace dot with +plus? + +This is just a different +algebra to work in, + +where plus actually means min, +and dot actually means plus. + +So, you have to check that +things sort of work out in that + +context, but if we do that, +then we get that c_ij is the + +min overall k of a_ik plus, +a bit messy here, + +b_kj. +And that looks like what we + +actually want to compute, +here, for one value of m, + +you have to sort of do this m +times. + +But this conceptually is +d_ij^(m), and this is + +d_ik^(m-1). +So, this is looking like a + +matrix product, +which is kind of cool. + +So, if we sort of plug in this +claim, then, and think about + +things as matrices, +the recurrence gives us, + +and I'll just write this now at +matrix form, that d^(m) is d^(m) + +minus one, funny product, +A. + +All right, so these are the +weights. + +These were the weighted +adjacency matrix. + +This was the previous d value. +This is the new d value. + +So, I'll just rewrite that in +matrix form with capital + +letters. +OK, I have the circle up things + +that are using this funny +algebra, so, in particular, + +circled product. +OK, so that's kind of nifty. + +We know something about +computing matrix + +multiplications. +We can do it in n^3 time. + +If we were a bit fancier, +maybe we could do it in + +sub-cubic time. +So, we could try to sort of use + +this connection. +And, well, think about what we + +are computing here. +We are saying, + +well, d to the m is the +previous one times A. + +So, what is d^(m)? +Is that some other algebraic + +notion that we know? +Yeah, it's the exponent. + +We're taking A, +and we want to raise it to the + +power, m, with this funny notion +of product. + +So, in other words, +d to the m is really just A to + +the m in a funny way. +So, I'll circle it, + +OK? +So, that sounds good. + +We also know how to compute +powers of things relatively + +quickly, if you remember how. +OK, for this notion, + +this power notion, +to make sense, + +I should say what A to the zero +means. + +And so, I need some kind of +identity matrix. + +And for here, +the identity matrix is this + +one, if I get it right. +So, it has zeros along the + +diagonal, and infinities +everywhere else. + +OK, that sort of just to match +this definition. + +d_ij zero should be zeros on +the diagonals and infinity + +everywhere else. +But you can check this is + +actually an identity. +If you multiply it with this + +funny multiplication against any +other matrix, + +you get the matrix back. +Nothing changes. + +This really is a valid identity +matrix. + +And, I should mention that for +A to the m to make sense, + +you really knew that your +product operation is + +associative. +So, actually A to the m circled + +makes sense because circled +multiplication is associative, + +and you can check that; +not hard because, + +I mean, min is associative, +and addition is associative, + +and all sorts of good stuff. +And, you have some kind of + +distributivity property. +And, this is, + +in turn, because the real +numbers with, + +and get the right order here, +with min as your addition + +operation, and plus as your +multiplication operation is a + +closed semi-ring. +So, if ever you want to know + +when powers make sense, +this is a good rule. + +If you have a closed semi-ring, +then matrix products on that + +semi-ring will give you an +associative operator, + +and then, good, +you can take products. + +OK, that's just some formalism. +So now, we have some intuition. + +The question is, +what's the right. + +Algorithm? +There are many possible + +answers, some of which are +right, some of which are not. + +So, we have this connection to +matrix products, + +and we have a connection to +matrix powers. + +And, we have algorithms for +both. + +The question is, +what should we do? + +So, all we need to do now is to +compute A to the funny power, + +n minus one. +n minus one is when we get + +shortest paths, +assuming we have no negative + +weight cycles. +In fact, we could compute a + +larger power than n minus one. +Once you get beyond n minus + +one, multipling by A doesn't +change you anymore. + +So, how should we do it? +OK, you're not giving any smart + +answers. +I'll give the stupid answer. + +You could say, +well, I take A. + +I multiply it by A. +Then I multiply it by A, + +and I multiply it by A, +and I use normal, + +boring matrix to +multiplication. + +So, I do, like, +n minus two, + +standard matrix multiplies. +So, standard multiply costs, + +like, n^3. +And I'm doing n of them. + +So, this gives me an n^4 +algorithm, and compute all the + +shortest pathways in n^4. +Woohoo! + +OK, no improvement. +So, how can I do better? + +Right, natural thing to try +which sadly does not work, + +is to use the sub cubic matrix +multiply algorithm. + +We will, in some sense, +get there in a moment with a + +somewhat simpler problem. +But, it's actually not known + +how to compute shortest paths +using fast matrix multiplication + +like Strassen's system +algorithm. + +But, good suggestion. +OK, you have to think about why + +it doesn't work, +and I'll tell you. + +It's not obvious, +so it's a perfectly reasonable + +suggestion. +But in this context it doesn't + +quite work. +It will come up in a few + +moments. +The problem is, + +Strassen requires the notion of +subtraction. + +And here, addition is min. +And, there's no inverse to min. + +Once you take the arguments, +you can't sort of undo a min. + +OK, so there's no notion of +subtraction, so it's not known + +how to pull that off, +sadly. + +So, what other tricks do we +have up our sleeve? + +Yeah? +Divide and conquer, + +log n powering, +yeah, repeated squaring. + +That works. +Good, we had a fancy way. + +If you had a number n, +you sort of looked at the + +binary number representation of +n, and you either squared the + +number or squared it and added +another factor of A. + +Here, we don't even have to be +smart about it. + +OK, we can just compute, +we really only have to think + +about powers of two. +What we want to know, + +and I'm going to need a bigger +font here because there's + +multiple levels of subscripts, +A to the circled power, + +two to the ceiling of log n. +Actually, n minus one would be + +enough. +But there you go. + +You can write n if you didn't +leave yourself enough space like + +me, n the ceiling, +n the circle. + +This just means the next power +of two after n minus one, + +two to the ceiling log. +So, we don't have to go + +directly to n minus one. +We can go further because + +anything farther than n minus +one is still just the shortest + +pathways. +If you look at the definition, + +and you know that your paths +are simple, which is true if you + +have no negative weight cycles, +then fine, just go farther. + +Why not? +And so, to compute this, + +we just do ceiling of log n +minus one products, + +just take A squared, +and then take the result and + +square it; take the result and +square it. + +So, this is order log n +squares. + +And, we don't know how to use +Strassen, but we can use the + +boring, standard multiply of +n^3, and that gives us n^3 log n + +running time, +OK, which finally is something + +that beats Bellman-Ford in the +dense case. + +OK, in the dense case, +Bellman-Ford was n^4. + +Here we get n^3 log n, +finally something better. + +In the sparse case, +it's about the same, + +maybe a little worse. +E is order V. + +Then we're going to get, +like, V3 for Bellman-Ford. + +Here, we get n^3 log n. +OK, after log factors, + +this is an improvement some of +the time. + +OK, it's about the same the +other times. + +Another nifty thing that you +get for free out of this, + +is you can detect negative +weight cycles. + +So, here's a bit of a puzzle. +How would I detect, + +after I compute this product, +A to the power to ceiling log n + +minus one, how would I know if I +found a negative weight cycle? + +What would that mean it this +matrix of all their shortest + +paths of, at most, +a certain length? + +If I found a cycle, +what would have to be in that + +matrix? +Yeah? + +Right, so I could, +for example, + +take this thing, +multiply it by A, + +see if the matrix changed at +all. + +Right, that works fine. +That's what we do in + +Bellman-Ford. +It's an even simpler thing. + +It's already there. +You don't have to multiply. + +But that's the same running +time. + +That's a good answer. +The diagonal would have a + +negative value, +yeah. + +So, this is just a cute thing. +Both approaches would work, + +can detect a negative weight +cycle just by looking at the + +diagonal of the matrix. +You just look for a negative + +value in the diagonal. +OK. + +So, that's algorithm one, +let's say. + +I mean, we've seen several that +are all bad, but I'll call this + +number one. +OK, we'll see two more. + +This is the only one that will, +well, I shouldn't say that. + +Fine, there we go. +So, this is one dynamic program + +that wasn't so helpful, +except it showed us a + +connection to matrix +multiplication, + +which is interesting. +We'll see why it's useful a + +little bit more. +But, it bled to this nasty four + +nested loops. +And, using this trick, + +we got down to n^3 log n. +Let's try, just for n^3. + +OK, just get rid of that log. +It's annoying. + +It makes you a little bit worse +than Bellman-Ford, + +and the sparse case. +So, let's just erase one of + +these nested loops. +OK, I want to do that. + +OK, obviously that algorithm +doesn't work because it's for + +first decay, and it's not +defined, but, + +you know, I've got enough +variables. + +Why don't I just define k to +the m? + +OK, it turns out that works. +I'll do it from scratch, + +but why not? +I don't know if that's how + +Floyd and Warshall came up with +their algorithm, + +but here you go. +Here's Floyd-Warshall. + +The idea is to define the +subproblems a little bit more + +cleverly so that to compute one +of these values, + +you don't have to take the min +of n things. + +I just want to take the min of +two things. + +If I could do that, +and I still only have n^3 + +subproblems, then I would have +n^3 time. + +So, all right, +the running time of dynamic + +program is number of subproblems +times the time to compute the + +recurrence for one subproblem. +So, here's linear times n^3, + +and we want n^3 times constant. +That would be good. + +So that's Floyd-Warshall. +So, here's the way we're going + +to redefine c_ij. +Or I guess, there it was called + +d_ij. +Good, so we're going to define + +something new. +So, c_ij superscript k is now + +going to be the weight of the +shortest path from I to j as + +before. +Notice I used the superscript k + +instead of m because I want k +and m to be the same thing. + +Deep. +OK, now, here's the new + +constraint. +I want all intermediate + +vertices along the path, +meeting all vertices except for + +I and j at the beginning and the +end to have a small label. + +So, they should be in the set +from one up to k. + +And this is where we are really +using that our vertices are + +labeled one up to m. +So, I'm going to say, + +well, first think about the +shortest paths that don't use + +any other vertices. +That's when k is zero. + +Then think about all the +shortest paths that maybe they + +use vertex one. +And then think about the + +shortest paths that maybe use +vertex one or vertex two. + +Why not? +You could define it in this + +way. +It turns out, + +then when you increase k, +you only have to think about + +one new vertex. +Here, we had to take min over + +all k. +Now we know which k to look at. + +OK, maybe that made sense. +Maybe it's not quite obvious + +yet. +But I'm going to redo this + +claim, redo a recurrence. +So, maybe first I should say + +some obvious things. +So, if I want delta of ij of + +the shortest pathway, +well, just take all the + +vertices. +So, take c_ij superscript n. + +That's everything. +And this even works, + +this is true even if you have a +negative weight cycle. + +Although, again, +we're going to sort of ignore + +negative weight cycles as long +as we can detect them. + +And, another simple case is if +you have, well, + +c_ij to zero. +Let me put that in the claim to + +be a little bit more consistent +here. + +So, here's the new claim. +If we want to compute c_ij + +superscript zero, +what is it? + +Superscript zero means I really +shouldn't use any intermediate + +vertices. +So, this has a very simple + +answer, a three letter answer. +So, it's not zero. + +It's four letters. +What's that? + +Nil. +No, not working yet. + +It has some subscripts, +too. + +So, the definition would be, +what's the shortest path weight + +from I to j when you're not +allowed to use any intermediate + +vertices? +Sorry? + +So, yeah, it has a very simple +name. + +That's the tricky part. +All right, so if i equals j, + +[LAUGHTER] you're clever, +right, open bracket i equals j + +means one, well, +OK. + +It sort of works, +but it's not quite right. + +In fact, I want infinity if i +does not equal j. + +And I want to zero if i equals +j, a_ij, good. + +I think it's a_ij. +It should be, + +right? +Maybe I'm wrong. + +Right, a_ij. +So it's essentially not what I + +said. +That's the point. + +If i does not equal j, +you still have to think about a + +single edge connecting i to j, +right? + +OK, so that's a bit of a +subtlety. + +This is only intermediate +vertices, so you could still go + +from i to j via a single edge. +That will cost a_ij. + +If there is an edge: +infinity. + +If there isn't one: +that is a_ij. + +So, OK, that gets us started. +And then, we want a recurrence. + +And, the recurrence is, +well, maybe you get away with + +all the vertices that you had +before. + +So, if you want to know paths +that you had before, + +so if you want to know paths +that use one up to k, + +maybe I just use one up to k +minus one. + +You could try that. +Or, you could try using k. + +So, either you use k or you +don't. + +If you don't, +it's got to be this. + +If you do, then you've got to +go to k. + +So why not go to k at the end? +So, you go from I to k using + +the previous vertices. +Obviously, you don't want to + +repeat k in there. +And then, you go from k to j + +somehow using vertices that are +not k. + +This should be pretty +intuitive. + +Again, I can draw a picture. +So, either you never go to k, + +and that's this wiggly line. +You go from i to j using things + +only one up to k minus one. +In other words, + +here we have to use one up to +k. + +So, this just means don't use +k. + +So, that's this thing. +Or, you use k somewhere in the + +middle there. +OK, it's got to be one of the + +two. +And in this case, + +you go from i to k using only +smaller vertices, + +because you don't want to +repeat k. + +And here, you go from k to j +using only smaller labeled + +vertices. +So, every path is one of the + +two. +So, we take the shortest of + +these two subproblems. +That's the answer. + +So, now we have a min of two +things. + +It takes constant time to +compute. + +So, we get a cubic algorithm. +So, let me write it down. + +So, this is the Floyd-Warshall +algorithm. + +I'll write the name again. +You give it a matrix A. + +That's all it really needs to +know. + +It codes everything. +You copy C to A. + +That's the warm up. +Right at time zero, + +C equals A. +And then you just have these + +three loops for every value of +k, for every value of i, + +and for every value of j. +You compute that min. + +And if you think about it a +little bit, that min is a + +relaxation. +Surprise, surprise. + +So, that is the Floyd-Warshall +algorithm. + +And, the running time is +clearly n^3, three nested loops, + +constant time inside. +So, we're finally getting + +something that is never worse +than Bellman-Ford. + +In the sparse case, +it's the same. + +And anything denser, +the number of edges is super + +linear. +This is strictly better than + +Bellman-Ford. +And, it's better than + +everything we've seen so far for +all pair, shortest paths. + +And, this handles negative +weights; very simple algorithm, + +even simpler than the one +before. + +It's just relaxation within +three loops. + +What more could you ask for? +And we need to check that this + +is indeed what min we're +computing here, + +except that the superscripts +are omitted. + +That's, again, +a bit of hand waving a bit. + +It's OK to omit subscripts +because that can only mean that + +you're doing more relaxation +techniques should be. + +Doing more relaxations can +never hurt you. + +In particular, +we do all the ones that we have + +to. +Therefore, we find the shortest + +path weights. +And, again, here, + +we're assuming that there is no +negative weight cycles. + +It shouldn't be hard to find +them, but you have to think + +about that a little bit. +OK, you could run another round + +of Bellman-Ford, +see if it relaxes in a new + +edges again. +For example, + +I think there's no nifty trick +for that version. + +And, we're going to cover, +that's our second algorithm for + +all pairs shortest paths. +Before we go up to the third + +algorithm, which is going to be +the cleverest of them all, + +the one Ring to rule them all, +to switch trilogies, + +we're going to take a little +bit of a diversion, + +side story, whatever, +and talk about transitive + +closure briefly. +This is just a good thing to + +know about. +And, it relates to the + +algorithms we've seen so far. +So, here's a transitive closure + +problem. +I give you a directed graph, + +and for all pair vertices, +i and j, I want to compute this + +number. +It's one if there's a path from + +i to j. +From i to j, + +OK, and then zero otherwise. +OK, this is sort of like a + +boring adjacency matrix with no +weights, except it's about paths + +instead of being about edges. +OK, so how can I compute this? + +That's very simple. +How should I compute this? + +This gives me a graph in some +sense. + +This is adjacency matrix of a +new graph called the transitive + +closure of my input graph. +So, breadth first search, + +yeah, good. +So, all I need to do is find + +shortest paths, +and if the weights come out + +infinity, then there's no path. +If it's less than infinity, + +that there's a path. +And so here, + +so you are saying maybe I don't +care about the weights, + +so I can run breadth first +search n times, + +and that will work indeed. +So, if we do B times B of S, + +so it's maybe weird that I'm +covering here in the middle, + +but it's just an interlude. +So, we have, + +then, something like V times E. +OK, you can run any of these + +algorithms. +You could take Floyd-Warshall + +for example. +Why not? + +OK, then it would just be V^ I +mean, you could run in any of + +these algorithms with weights of +one or zero, and just check + +whether the values are infinity +or not. + +So, I mean, t_ij equals zero, +if and only if the shortest + +path weight from i to j is +infinity. + +So, just solve this. +This is an easier problem than + +shortest paths. +It is, in fact, + +strictly easier in a certain +sense, because what's going on + +with transitive closure, +and I just want to mention this + +out of interest because +transitive closure is a useful + +thing to know about. +Essentially, + +what we are doing, +let me get this right, + +is using a different set of +operators. + +We're using or and and, +a logical or and and instead of + +min and plus, +OK, because we want to know, + +if you think about a +relaxation, in some sense, + +maybe I should think about it +in terms of this min. + +So, if I want to know, +is there a pathway from I to j + +that uses vertices labeled one +through k in the middle? + +Well, either there is a path +that doesn't use the vertex k, + +or there is a path that uses k, +and then it would have to look + +like that. +OK, so there would have to be a + +path here, and there would have +to be a path there. + +So, the min and plus get +replaced with or and and. + +And if you remember, +this used to be plus, + +and this used to be product in +the matrix world. + +So, plus is now like or. +And, multiply is now like and, + +which sounds very good, +right? + +Plus does feel like or, +and multiply does feel like and + +if you live in a zero-one world. +So, in fact, + +this is not quite the field Z +mod two, but this is a good, + +nice, field to work in. +This is the Boolean world. + +So, I'll just write Boole. +Good old Boole knows all about + +this. +It's like his master's thesis, + +I think, talking about Boolean +algebra. + +And, this actually means that +you can use fast matrix + +multiply. +You can use Strassen's + +algorithm, and the fancier +algorithms, and you can compute + +the transitive closure in +subcubic time. + +So, this is sub cubic if the +edges are sparse. + +But, it's cubic in the worst +case if there are lots of edges. + +This is cubic. +You can actually do better + +using Strassen. +So, I'll just say you can do + +it. +No details here. + +I think it should be, +so in fact, there is a theorem. + +This is probably not in the +textbook, but there's a theorem + +that says transitive closure is +just as hard as matrix multiply. + +OK, they are equivalent. +Their running times are the + +same. +We don't know how long it takes + +to do a matrix multiply over a +field. + +It's somewhere between n^2 and +n^2.3. + +But, whatever the answer is: +same for transitive closure. + +OK, there's the interlude. +And that's where we actually + +get to use Strassen and friends. +Remember, Strassen was n to the + +log base two of seven algorithm. +Remember that, + +especially on the final. +Those are things you should + +have at the tip of your tongue. +OK, the last algorithm we're + +going to cover is really going +to build on what we saw last + +time: Johnson's algorithm. +And, I've lost some of the + +running times here. +But, when we had unweighted + +graphs, we could do all pairs +really fast, just as fast as a + +single source Bellman-Ford. +That's kind of nifty. + +We don't know how to improve +Bellman-Ford in the single + +source case. +So, we can't really help to get + +anything better than V times E. +And, if you remember running V + +times Dijkstra, +V times Dijkstra was about the + +same. +So, just put this in the recall + +bubble here: V times Dijkstra +would give us V times E plus V^2 + +log V. +And, if you ignore that log + +factor, this is just VE. +OK, so this was really good. + +Dijkstra was great. +And this was for nonnegative + +edge weights. +So, with negative edge weights, + +somehow we'd like to get the +same running time. + +Now, how might I get the same +running time? + +Well, it would be really nice +if I could use Dijkstra. + +Of course, Dijkstra doesn't +work with negative weights. + +So what could I do? +What would I hope to do? + +What could I hope to? +Suppose I want, + +in the middle of the algorithm, +it says run Dijkstra n times. + +Then, what should I do to +prepare for that? + +Make all the weights positive, +or nonnegative. + +Why not, right? +We're being wishful thinking. + +That's what we'll do. +So, this is called graph + +re-weighting. +And, what's cool is we actually + +already know how to do it. +We just don't know that we know + +how to do it. +But I know that we know that we + +know how to do it. +You don't yet know that we know + +that I know that we know how to +do it. + +So, it turns out you can +re-weight the vertices. + +So, at the end of the last +class someone asked me, + +can you just, +like, add the same weight to + +all the edges? +That doesn't work. + +Not quite, because different +paths have different numbers of + +edges. +What we are going to do is add + +a particular weight to each +vertex. + +What does that mean? +Well, because we really only + +have weights on the edges, +here's what well do. + +We'll re-weight each edge, +so, (u,v), let's say, + +going to go back into graph +speak instead of matrix speak, + +(u,v) instead of I and j, +and we'll call this modified + +weight w_h. +h is our function. + +It gives us a number for every +vertex. + +And, it's just going to be the +old weight of that edge plus the + +weight of the start vertex minus +the weight of the terminating + +vertex. +I'm sure these have good names. + +One of these is the head, +and the other is the tail, + +but I can never remember which. +OK, so we've directed edge + +(u,v). +Just add one of them; + +subtract the other. +And, it's a directed edge, + +so that's a consistent +definition. + +OK, so that's called +re-weighting. + +Now, this is actually a +theorem. + +If you do this, +then, let's say, + +for any vertices, +u and v in the graph, + +for any two vertices, +all paths from u to v have the + +same weight as they did before, +well, not quite. + +They have the same +re-weighting. + +So, if you look at all the +different paths and you say, + +well, what's the difference +between vh, well, + +sorry, let's say delta, +which is the old shortest + +paths, and deltas of h, +which is the shortest path + +weights according to this new +weight function, + +then that difference is the +same. + +So, we'll say that all these +paths are re-weighted by the + +same amounts. +OK, this is actually a + +statement about all paths, +not just shortest paths. + +There we go. +OK, to how many people is this + +obvious already? +A few, yeah, + +it is. +And what's the one word? + +OK, it's maybe not that +obvious. + +All right, shout out the word +when you figure it out. + +Meanwhile, I'll write out this +rather verbose proof. + +There's a one word proof, +still waiting. + +So, let's just take one of +these paths that starts at u and + +ends at v. +Take any path. + +We're just going to see what +its new weight is relative to + +its old weight. +And so, let's just write out + +w_h of the path, +which we define in the usual + +way as the sum over all edges of +the new weight of the edge from + +v_i to v_i plus one. +Do you have the word? + +No? +Tough puzzle then, + +OK. +So that's the definition of the + +weight of a path. +And, then we know this thing is + +just w of v_i, +v_i plus one. + +I'll get it right, +plus the weight of the first + +vertex, plus, +sorry, the re-weighting of v_i + +minus the re-weighting of v_i +plus one. + +This is all in parentheses +that's summed over I. + +Now I need the magic word. +Telescopes, good. + +Now this is obvious: +each of these telescopes with + +an extra previous, +except the very beginning and + +the very end. +So, this is the sum of these + +weights of edges, +but then outside the sum, + +we have plus h of v_1, +and minus h of v_k. + +OK, those guys don't quite +cancel. + +We're not looking at a cycle, +just a path. + +And, this thing is just w of +the path, as this is the normal + +weight of the path. +And so the change, + +the difference between w_h of P +and w of P is this thing, + +which is just h of u minus h of +v. + +And, the point is that's the +same as long as you fix the + +endpoints, u and v, +of the shortest path, + +you're changing this path +weight by the same thing for all + +paths. +This is for any path from u to + +v, and that proves the theorem. +So, the one word here was + +telescopes. +These change in weights + +telescope over any path. +Therefore, if we want to find + +shortest paths, +you just find the shortest + +paths in this re-weighted +version, and then you just + +change it by this one amount. +You subtract off this amount + +instead of adding it. +That will give you the shortest + +path weight in the original +weights. + +OK, so this is a tool. +We now know how to change + +weights in the graph. +But what we really want is to + +change weights in the graph so +that the weights all come out + +nonnegative. +OK, how do we do that? + +Why in the world would there be +a function, h, + +that makes all the edge weights +nonnegative? + +It doesn't make sense. +It turns out we already know. + +So, I should write down this +consequence. + +Let me get this in the right +order. + +So in particular, +the shortest path changes by + +this amount. +And if you want to know this + +value, you just move the stuff +to the other side. + +So, we compute deltas of h, +then we can compute delta. + +That's the consequence here. +How many people here pronounce + +this word corollary? +OK, and how many people + +pronounce it corollary? +Yeah, we are alone. + +Usually get at least one other +student, and they're usually + +Canadian or British or +something. + +I think that the accent. +So, I always avoid pronouncing + +his word unless I really think, +it's corollary, + +and get it right. +I at least say Z not Zed. + +OK, here we go. +So, what we want to do is find + +one of these functions. +I mean, let's just write down + +what we could hope to have. +We want to find a re-weighted + +function, h, the signs of weight +to each vertex such that w_h of + +(u,v) is nonnegative. +That would be great for all + +edges, all (u,v) in E. +OK, then we could run Dijkstra. + +We could run Dijkstra, +get the delta h's, + +and then just undo the +re-weighting, + +and get what we want. +And, that is Johnson's + +algorithm. +The claim is that this is + +always possible. +OK, why should it always be + +possible? +Well, let's look at this + +constraint. +w_h of (u,v) is that. + +So, it's w of (u,v) plus h of u +minus h of V should be + +nonnegative. +Let me rewrite this a little + +bit. +I'm going to put these guys + +over here. +That would be the right thing, + +h of v minus h of u is less +than or equal to w of (u,v). + +Does that look familiar? +Did I get it right? + +It should be right. +Anyone seen that inequality + +before? +Yeah, yes, correct answer. + +OK, where? +In a previous lecture? + +In the previous lecture. +What is this called if I + +replace h with x? +Charles knows. + +Good, anyone else remember all +the way back to episode two? + +I know there was a weekend. +What's this operator called? + +Not subtraction but, +I think I heard it, + +oh man. +All right, I'll tell you. + +It's a difference constraint, +all right? + +This is the difference +operator. + +OK, it's our good friend +difference constraints. + +So, this is what we want to +satisfy. + +We have a system of difference +constraints. + +h of V minus h of u should be, +we want to find these. + +These are our unknowns. +Subject to these constraints, + +we are given the w's. +Now, we know in these + +difference constraints are +satisfiable. + +Can someone tell me when these +constraints are satisfiable? + +We know exactly when for any +set of difference constraints. + +You've got to remember the +math. + +Terminology, +I can understand. + +It's hard to remember words +unless you're a linguist, + +perhaps. +So, when is the system of + +different constraints +satisfiable? + +All right, you should +definitely, very good. + +[LAUGHTER] Yes, +very good. + +Someone brought their lecture +notes: when the constraint graph + +has no negative weight cycles. +Good, thank you. + +Now, what is the constraint +graph? + +OK, this has a one letter +answer more or less. + +I'll accept the one letter +answer. + +What? +A? + +A: close. +G. + +Yeah, I mean, +same thing. + +Yeah, so the constraint graph +is essentially G. + +Actually, it is G. +The constraint graph is G, + +good. +And, we prove this by adding a + +new source for text, +and connecting that to + +everyone. +But that's sort of beside the + +point. +That was in order to actually + +satisfy them. +But this is our + +characterization. +So, if we assume that there are + +no negative weight cycles in our +graph, which we've been doing + +all the time, +then we know that this thing is + +satisfiable. +Therefore, there is an + +assignment of this h's. +There is a re-weighting that + +makes all the weights +nonnegative. + +Then we can run Dijkstra. +OK, we're done. + +Isn't that cool? +And how do we satisfy these + +constraints? +We know how to do that with one + +run of Bellman-Ford, +which costs order VE, + +which is less than V times +Dijkstra. + +So, that's it, +write down the details + +somewhere. + +So, this is Johnson's +algorithm. + +This is the fanciest of them +all. + +It will be our fastest, +all pairs shortest path + +algorithm. +So, the claim is, + +we can find a function, +h, from V to R such that the + +modified weight of every edge is +nonnegative for every edge, + +(u,v), in our graph. +And, we do that using + +Bellman-Ford to solve the +difference constraints. + +These are exactly the different +constraints that we were born to + +solve that we learned to solve +last time. + +The graphs here are +corresponding exactly if you + +look back at the definition. +Or, Bellman-Ford will tell us + +that there is a negative weight +cycle. + +OK, great, so it's not that we +really have to assume that there + +is no negative weight cycle. +We'll get to know. + +And if your fancy, +you can actually figure out the + +minus infinities from this. +But, at this point, + +I just want to think about the +case where there is no negative + +weight cycle. +But if there is, + +we can find out that it exists, +and that just tell the user. + +OK, then we'd stop. +Otherwise, there is no negative + +weight cycle. +Therefore, there is an + +assignment that gives is +nonnegative edge weights. + +So, we just use it. +We use it to run Dijkstra. + +So, step two is, +oh, I should say the running + +time of all this is V times E. +So, we're just running + +Bellman-Ford on exactly the +input graph. + +Plus, we add a source, +if you recall, + +to solve a set of difference +constraints. + +You add a source vertex, +S, connected to everyone at + +weight zero, run Bellman-Ford +from there because we don't have + +a source here. +We just have a graph. + +We want to know all pairs. +So, this, you can use to find + +whether there is a negative +weight cycle anywhere. + +Or, we get this magic +assignment. + +So now, w_h is nonnegative, +so we can run Dijkstra on w_h. + +We'll say, using w_h, +so you compute w_h. + +That takes linear time. +And, we run Dijkstra for each + +possible source. +I'll write this out explicitly. + +We've had this in our minds +several times. + +But, when we said n times +Dijkstra over n times BFS, + +here it is. +We want to compute delta sub h + +now, of (u,v) for all V, +and we do this separately for + +all u. +And so, the running time here + +is VE plus V^2 log V. +This is just V times the + +running time of Dijkstra, +which is E plus V log V. + +OK, it happens that this term +is the same as this one, + +which is nice, +because that means step one + +costs us nothing asymptotically. +OK, and then, + +last step is, +well, now we know delta h. + +We just need to compute delta. +So, for each pair of vertices, + +we'll call it (u,v), +we just compute what the + +original weights would be, +so what delta (u,v) is. + +And we can do that using this +corollary. + +It's just delta sub h of (u,v) +minus h of u plus h of v. + +I got the signs right. +Yeah, so this takes V^2 time, + +also dwarfed by the running +time of Dijkstra. + +So, the overall running time of +Johnson's algorithm is just the + +running time of step two, +running Dijkstra n times -- + +-- which is pretty cool. +When it comes to single source + +shortest paths, +Bellman-Ford is the best thing + +for general weights. +Dijkstra is the best thing for + +nonnegative weights. +But for all pair shortest + +paths, we can skirt the whole +negative weight issue by using + +this magic we saw from +Bellman-Ford. + +But now, running Dijkstra n +times, which is still the best + +thing we know how to do, +pretty much, + +for the all pairs nonnegative +weights, now we can do it for + +general weights too, +which is a pretty nice + +combination of all the +techniques we've seen. + +In the trilogy, +and along the way, + +we saw lots of dynamic +programming, which is always + +good practice. +Any questions? + +This is the last new content +lecture before the quiz. + +On Wednesday it will be quiz +review, if I recall correctly. + +And then it's Thanksgiving, +so there's no recitation. + +And then the quiz starts on +Monday. + +So, study up. +See you then. \ No newline at end of file diff --git a/Tl_p5pgBsyM.txt b/Tl_p5pgBsyM.txt new file mode 100644 index 0000000000000000000000000000000000000000..9a552740c1377cf66492e5e9c239a14680eb459c --- /dev/null +++ b/Tl_p5pgBsyM.txt @@ -0,0 +1,9960 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT open courseware continue + + align:start position:0% +will help MIT open courseware continue + + + align:start position:0% +will help MIT open courseware continue +to offer highquality educational + + align:start position:0% +to offer highquality educational + + + align:start position:0% +to offer highquality educational +resources for free to make a donation or + + align:start position:0% +resources for free to make a donation or + + + align:start position:0% +resources for free to make a donation or +view additional materials from hundreds + + align:start position:0% +view additional materials from hundreds + + + align:start position:0% +view additional materials from hundreds +of MIT courses visit mitop courseware at + + align:start position:0% + + + + align:start position:0% + +ocw.mit.edu this week's problem is from + + align:start position:0% +ocw.mit.edu this week's problem is from + + + align:start position:0% +ocw.mit.edu this week's problem is from +the 2008 uh quiz one on search is + + align:start position:0% +the 2008 uh quiz one on search is + + + align:start position:0% +the 2008 uh quiz one on search is +motivated by the search of evil Overlord + + align:start position:0% +motivated by the search of evil Overlord + + + align:start position:0% +motivated by the search of evil Overlord +Mark Vader who is shopping for a new + + align:start position:0% +Mark Vader who is shopping for a new + + + align:start position:0% +Mark Vader who is shopping for a new +evil stronghold he starts from his + + align:start position:0% +evil stronghold he starts from his + + + align:start position:0% +evil stronghold he starts from his +current stronghold which is s the depth + + align:start position:0% +current stronghold which is s the depth + + + align:start position:0% +current stronghold which is s the depth +first search Star now the depth first + + align:start position:0% +first search Star now the depth first + + + align:start position:0% +first search Star now the depth first +search Star has the following qualities + + align:start position:0% +search Star has the following qualities + + + align:start position:0% +search Star has the following qualities +it has a small thermal exhaust pipe + + align:start position:0% +it has a small thermal exhaust pipe + + + align:start position:0% +it has a small thermal exhaust pipe +weakness it has the quality of that's no + + align:start position:0% +weakness it has the quality of that's no + + + align:start position:0% +weakness it has the quality of that's no +moon but it does not have a race of + + align:start position:0% +moon but it does not have a race of + + + align:start position:0% +moon but it does not have a race of +enslaved minions or a secret Escape + + align:start position:0% +enslaved minions or a secret Escape + + + align:start position:0% +enslaved minions or a secret Escape +Route or sharks with laser + + align:start position:0% +Route or sharks with laser + + + align:start position:0% +Route or sharks with laser +beams now when I originally wrote this + + align:start position:0% +beams now when I originally wrote this + + + align:start position:0% +beams now when I originally wrote this +problem in 2008 there was another + + align:start position:0% +problem in 2008 there was another + + + align:start position:0% +problem in 2008 there was another +quality that was very important that was + + align:start position:0% +quality that was very important that was + + + align:start position:0% +quality that was very important that was +a giant laser and it did have that + + align:start position:0% +a giant laser and it did have that + + + align:start position:0% +a giant laser and it did have that +property as did Dr Evil's W base but + + align:start position:0% +property as did Dr Evil's W base but + + + align:start position:0% +property as did Dr Evil's W base but +that was removed to make it easier to + + align:start position:0% +that was removed to make it easier to + + + align:start position:0% +that was removed to make it easier to +solve so we're going to solve it without + + align:start position:0% +solve so we're going to solve it without + + + align:start position:0% +solve so we're going to solve it without +the without the giant laser that we can + + align:start position:0% +the without the giant laser that we can + + + align:start position:0% +the without the giant laser that we can +just have the sharks with blazer beams + + align:start position:0% + + + + align:start position:0% + +so Mark Vader has gone to akar's + + align:start position:0% +so Mark Vader has gone to akar's + + + align:start position:0% +so Mark Vader has gone to akar's +Emporium of uh new evil strongholds + + align:start position:0% +Emporium of uh new evil strongholds + + + align:start position:0% +Emporium of uh new evil strongholds +which are listed on the left and he's + + align:start position:0% +which are listed on the left and he's + + + align:start position:0% +which are listed on the left and he's +trying to figure out the best way to um + + align:start position:0% +trying to figure out the best way to um + + + align:start position:0% +trying to figure out the best way to um +get from his current stronghold to his + + align:start position:0% +get from his current stronghold to his + + + align:start position:0% +get from his current stronghold to his +goal stronghold the 603 Fortress which + + align:start position:0% +goal stronghold the 603 Fortress which + + + align:start position:0% +goal stronghold the 603 Fortress which +has the aborable qualities of no small + + align:start position:0% +has the aborable qualities of no small + + + align:start position:0% +has the aborable qualities of no small +thermal exhaust pipe weakness and it + + align:start position:0% +thermal exhaust pipe weakness and it + + + align:start position:0% +thermal exhaust pipe weakness and it +still has that's no moon it has a race + + align:start position:0% +still has that's no moon it has a race + + + align:start position:0% +still has that's no moon it has a race +of enslaved minions and a secret Escape + + align:start position:0% +of enslaved minions and a secret Escape + + + align:start position:0% +of enslaved minions and a secret Escape +Route and sharks with blazer beams which + + align:start position:0% +Route and sharks with blazer beams which + + + align:start position:0% +Route and sharks with blazer beams which +so it's got everything you would want + + align:start position:0% +so it's got everything you would want + + + align:start position:0% +so it's got everything you would want +and no weakness however he can only uh + + align:start position:0% +and no weakness however he can only uh + + + align:start position:0% +and no weakness however he can only uh +move between fortresses that have + + align:start position:0% +move between fortresses that have + + + align:start position:0% +move between fortresses that have +exactly one + + align:start position:0% +exactly one + + + align:start position:0% +exactly one +difference fortunately Mark remembers + + align:start position:0% +difference fortunately Mark remembers + + + align:start position:0% +difference fortunately Mark remembers +how to perform the search techniques he + + align:start position:0% +how to perform the search techniques he + + + align:start position:0% +how to perform the search techniques he +learned in 6034 from his mentor Emperor + + align:start position:0% +learned in 6034 from his mentor Emperor + + + align:start position:0% +learned in 6034 from his mentor Emperor +Patrick teen so we've got several + + align:start position:0% +Patrick teen so we've got several + + + align:start position:0% +Patrick teen so we've got several +fortresses here we've got the dep for + + align:start position:0% +fortresses here we've got the dep for + + + align:start position:0% +fortresses here we've got the dep for +search Star we've also um got sh + + align:start position:0% +search Star we've also um got sh + + + align:start position:0% +search Star we've also um got sh +ghoul which has um the the quality is + + align:start position:0% +ghoul which has um the the quality is + + + align:start position:0% +ghoul which has um the the quality is +basically of that's no moon and none of + + align:start position:0% +basically of that's no moon and none of + + + align:start position:0% +basically of that's no moon and none of +the other qualities DOL gor here has got + + align:start position:0% +the other qualities DOL gor here has got + + + align:start position:0% +the other qualities DOL gor here has got +the uh exhaust pipe weakness somehow + + align:start position:0% +the uh exhaust pipe weakness somehow + + + align:start position:0% +the uh exhaust pipe weakness somehow +despite being saon stronghold uh it's + + align:start position:0% +despite being saon stronghold uh it's + + + align:start position:0% +despite being saon stronghold uh it's +not a moon and it has those enslaved + + align:start position:0% +not a moon and it has those enslaved + + + align:start position:0% +not a moon and it has those enslaved +minions I guess the Orcs are enslaved + + align:start position:0% +minions I guess the Orcs are enslaved + + + align:start position:0% +minions I guess the Orcs are enslaved +Moon raker here uh only has exhaust pipe + + align:start position:0% +Moon raker here uh only has exhaust pipe + + + align:start position:0% +Moon raker here uh only has exhaust pipe +weakness so it's it's not very good but + + align:start position:0% +weakness so it's it's not very good but + + + align:start position:0% +weakness so it's it's not very good but +James Bond didn't need to deal with + + align:start position:0% +James Bond didn't need to deal with + + + align:start position:0% +James Bond didn't need to deal with +stuff uh Zeal Underwater Palace has + + align:start position:0% +stuff uh Zeal Underwater Palace has + + + align:start position:0% +stuff uh Zeal Underwater Palace has +that's no moon and a secret Escape Route + + align:start position:0% +that's no moon and a secret Escape Route + + + align:start position:0% +that's no moon and a secret Escape Route +zeris is lunar core has an exhaust pipe + + align:start position:0% +zeris is lunar core has an exhaust pipe + + + align:start position:0% +zeris is lunar core has an exhaust pipe +weakness and a race of enslaved minions + + align:start position:0% +weakness and a race of enslaved minions + + + align:start position:0% +weakness and a race of enslaved minions +Whalers of the moon rde has the exhaust + + align:start position:0% +Whalers of the moon rde has the exhaust + + + align:start position:0% +Whalers of the moon rde has the exhaust +pipe weakness race of enslaved minions + + align:start position:0% +pipe weakness race of enslaved minions + + + align:start position:0% +pipe weakness race of enslaved minions +and sharks with laser beams 603 Fortress + + align:start position:0% +and sharks with laser beams 603 Fortress + + + align:start position:0% +and sharks with laser beams 603 Fortress +we've already been over at Atlantis has + + align:start position:0% +we've already been over at Atlantis has + + + align:start position:0% +we've already been over at Atlantis has +all qualities except for a secret Escape + + align:start position:0% +all qualities except for a secret Escape + + + align:start position:0% +all qualities except for a secret Escape +Route Wily Wonka's factory has some of + + align:start position:0% +Route Wily Wonka's factory has some of + + + align:start position:0% +Route Wily Wonka's factory has some of +everything it is after all Willy Wonka's + + align:start position:0% +everything it is after all Willy Wonka's + + + align:start position:0% +everything it is after all Willy Wonka's +factory highlight the race of enslaved + + align:start position:0% +factory highlight the race of enslaved + + + align:start position:0% +factory highlight the race of enslaved +minions the Oompa loomas and Dr Evil's + + align:start position:0% +minions the Oompa loomas and Dr Evil's + + + align:start position:0% +minions the Oompa loomas and Dr Evil's +moon base is only missing that's no moon + + align:start position:0% +moon base is only missing that's no moon + + + align:start position:0% +moon base is only missing that's no moon +because it is a moon because it's a moon + + align:start position:0% +because it is a moon because it's a moon + + + align:start position:0% +because it is a moon because it's a moon +base + + align:start position:0% +base + + + align:start position:0% +base +so if you got all the references that + + align:start position:0% +so if you got all the references that + + + align:start position:0% +so if you got all the references that +were used to make those fortresses I'm + + align:start position:0% +were used to make those fortresses I'm + + + align:start position:0% +were used to make those fortresses I'm +sorry there's nothing I can do for you + + align:start position:0% + + + + align:start position:0% + +OHS now Mark being a clever evil + + align:start position:0% +OHS now Mark being a clever evil + + + align:start position:0% +OHS now Mark being a clever evil +Overlord realizes that he can grp + + align:start position:0% +Overlord realizes that he can grp + + + align:start position:0% +Overlord realizes that he can grp +produce a graph of the exploration + + align:start position:0% +produce a graph of the exploration + + + align:start position:0% +produce a graph of the exploration +choices with edges joining strongholds + + align:start position:0% +choices with edges joining strongholds + + + align:start position:0% +choices with edges joining strongholds +that differ by just one feature so + + align:start position:0% +that differ by just one feature so + + + align:start position:0% +that differ by just one feature so +although there's a graph here as Patrick + + align:start position:0% +although there's a graph here as Patrick + + + align:start position:0% +although there's a graph here as Patrick +often says and you'll get to hear again + + align:start position:0% +often says and you'll get to hear again + + + align:start position:0% +often says and you'll get to hear again +right now search is about choice not + + align:start position:0% +right now search is about choice not + + + align:start position:0% +right now search is about choice not +just about Maps so we're not moving + + align:start position:0% +just about Maps so we're not moving + + + align:start position:0% +just about Maps so we're not moving +around anywhere in the real world but we + + align:start position:0% +around anywhere in the real world but we + + + align:start position:0% +around anywhere in the real world but we +certainly are going to move around this + + align:start position:0% +certainly are going to move around this + + + align:start position:0% +certainly are going to move around this +graph to pick between these many + + align:start position:0% +graph to pick between these many + + + align:start position:0% +graph to pick between these many +stronghold choices how can we decide + + align:start position:0% +stronghold choices how can we decide + + + align:start position:0% +stronghold choices how can we decide +where to travel while we're about to + + align:start position:0% +where to travel while we're about to + + + align:start position:0% +where to travel while we're about to +find out so we've got this lovely graph + + align:start position:0% +find out so we've got this lovely graph + + + align:start position:0% +find out so we've got this lovely graph +right here and now we're going to get to + + align:start position:0% +right here and now we're going to get to + + + align:start position:0% +right here and now we're going to get to +do depth ver search on the + + align:start position:0% +do depth ver search on the + + + align:start position:0% +do depth ver search on the +graph now there's a lot of ways to do + + align:start position:0% +graph now there's a lot of ways to do + + + align:start position:0% +graph now there's a lot of ways to do +search and you've seen Patrick do it you + + align:start position:0% +search and you've seen Patrick do it you + + + align:start position:0% +search and you've seen Patrick do it you +may have seen some people do it in + + align:start position:0% +may have seen some people do it in + + + align:start position:0% +may have seen some people do it in +recitation and I'm going to offer you + + align:start position:0% +recitation and I'm going to offer you + + + align:start position:0% +recitation and I'm going to offer you +guys a unique opportunity to see me do + + align:start position:0% +guys a unique opportunity to see me do + + + align:start position:0% +guys a unique opportunity to see me do +search in one of several ways or + + align:start position:0% +search in one of several ways or + + + align:start position:0% +search in one of several ways or +possibly more I have the tried and true + + align:start position:0% +possibly more I have the tried and true + + + align:start position:0% +possibly more I have the tried and true +method you have the cue or agenda or + + align:start position:0% +method you have the cue or agenda or + + + align:start position:0% +method you have the cue or agenda or +whatever you want to call it you keep + + align:start position:0% +whatever you want to call it you keep + + + align:start position:0% +whatever you want to call it you keep +track of it at every level you make damn + + align:start position:0% +track of it at every level you make damn + + + align:start position:0% +track of it at every level you make damn +sure that everything you're doing is + + align:start position:0% +sure that everything you're doing is + + + align:start position:0% +sure that everything you're doing is +right it takes a long time and you got + + align:start position:0% +right it takes a long time and you got + + + align:start position:0% +right it takes a long time and you got +the answer right or there's one where + + align:start position:0% +the answer right or there's one where + + + align:start position:0% +the answer right or there's one where +you only work with the gold tree and you + + align:start position:0% +you only work with the gold tree and you + + + align:start position:0% +you only work with the gold tree and you +draw it really fast and you might make a + + align:start position:0% +draw it really fast and you might make a + + + align:start position:0% +draw it really fast and you might make a +mistake but it's going to solve it more + + align:start position:0% +mistake but it's going to solve it more + + + align:start position:0% +mistake but it's going to solve it more +quickly so who would rather see the + + align:start position:0% +quickly so who would rather see the + + + align:start position:0% +quickly so who would rather see the +reliable but slower approach + + align:start position:0% + + + + align:start position:0% + +who'd rather see the faster but less + + align:start position:0% +who'd rather see the faster but less + + + align:start position:0% +who'd rather see the faster but less +reliable approach all right mon Carlo + + align:start position:0% +reliable approach all right mon Carlo + + + align:start position:0% +reliable approach all right mon Carlo +people here rather than Las Vegas if you + + align:start position:0% +people here rather than Las Vegas if you + + + align:start position:0% +people here rather than Las Vegas if you +don't know what that is you'll learn it + + align:start position:0% +don't know what that is you'll learn it + + + align:start position:0% +don't know what that is you'll learn it +in algorithm's class all right then + + align:start position:0% +in algorithm's class all right then + + + align:start position:0% +in algorithm's class all right then +there's a third approach that I probably + + align:start position:0% +there's a third approach that I probably + + + align:start position:0% +there's a third approach that I probably +won't show you unless there's + + align:start position:0% +won't show you unless there's + + + align:start position:0% +won't show you unless there's +overwhelming favor for it that is the + + align:start position:0% +overwhelming favor for it that is the + + + align:start position:0% +overwhelming favor for it that is the +approach that is manically fast and will + + align:start position:0% +approach that is manically fast and will + + + align:start position:0% +approach that is manically fast and will +solve depth search in no time at all but + + align:start position:0% +solve depth search in no time at all but + + + align:start position:0% +solve depth search in no time at all but +is very likely to make + + align:start position:0% +is very likely to make + + + align:start position:0% +is very likely to make +mistakes uh that is the approach that I + + align:start position:0% +mistakes uh that is the approach that I + + + align:start position:0% +mistakes uh that is the approach that I +use when solving depth for search and + + align:start position:0% +use when solving depth for search and + + + align:start position:0% +use when solving depth for search and +I've used it enough times that I don't + + align:start position:0% +I've used it enough times that I don't + + + align:start position:0% +I've used it enough times that I don't +make mistakes that often but even I + + align:start position:0% +make mistakes that often but even I + + + align:start position:0% +make mistakes that often but even I +still do so does anyone want to see that + + align:start position:0% +still do so does anyone want to see that + + + align:start position:0% +still do so does anyone want to see that +one okay not that many people well it + + align:start position:0% +one okay not that many people well it + + + align:start position:0% +one okay not that many people well it +doesn't take much time but I'm just + + align:start position:0% +doesn't take much time but I'm just + + + align:start position:0% +doesn't take much time but I'm just +afraid if I show it to you that you'll + + align:start position:0% +afraid if I show it to you that you'll + + + align:start position:0% +afraid if I show it to you that you'll +be like oh that's the only way to do it + + align:start position:0% +be like oh that's the only way to do it + + + align:start position:0% +be like oh that's the only way to do it +so we'll say that for later if we have + + align:start position:0% +so we'll say that for later if we have + + + align:start position:0% +so we'll say that for later if we have +more time it essentially if people are + + align:start position:0% +more time it essentially if people are + + + align:start position:0% +more time it essentially if people are +interested involves just using your + + align:start position:0% +interested involves just using your + + + align:start position:0% +interested involves just using your +chalk or finger to trace through the + + align:start position:0% +chalk or finger to trace through the + + + align:start position:0% +chalk or finger to trace through the +tree really fast and figure out what + + align:start position:0% +tree really fast and figure out what + + + align:start position:0% +tree really fast and figure out what +it's doing + + align:start position:0% +it's doing + + + align:start position:0% +it's doing +by drawing little tiny lines it it is + + align:start position:0% +by drawing little tiny lines it it is + + + align:start position:0% +by drawing little tiny lines it it is +very fast but it's not very accurate and + + align:start position:0% +very fast but it's not very accurate and + + + align:start position:0% +very fast but it's not very accurate and +and you have shown basically no work if + + align:start position:0% +and you have shown basically no work if + + + align:start position:0% +and you have shown basically no work if +you get it wrong so shame on you + + align:start position:0% +you get it wrong so shame on you + + + align:start position:0% +you get it wrong so shame on you +okay well let's do the somewhat faster + + align:start position:0% +okay well let's do the somewhat faster + + + align:start position:0% +okay well let's do the somewhat faster +way we don't draw out the entire agenda + + align:start position:0% +way we don't draw out the entire agenda + + + align:start position:0% +way we don't draw out the entire agenda +and then people who were the almost + + align:start position:0% +and then people who were the almost + + + align:start position:0% +and then people who were the almost +nobody who raised their hand for that + + align:start position:0% +nobody who raised their hand for that + + + align:start position:0% +nobody who raised their hand for that +way can um check it out in tutorial um + + align:start position:0% +way can um check it out in tutorial um + + + align:start position:0% +way can um check it out in tutorial um +the way that you do it using the agenda + + align:start position:0% +the way that you do it using the agenda + + + align:start position:0% +the way that you do it using the agenda +so let's do it using the goal tree it's + + align:start position:0% +so let's do it using the goal tree it's + + + align:start position:0% +so let's do it using the goal tree it's +so it's a bit faster that way so we're + + align:start position:0% +so it's a bit faster that way so we're + + + align:start position:0% +so it's a bit faster that way so we're +going to search starting at s the start + + align:start position:0% +going to search starting at s the start + + + align:start position:0% +going to search starting at s the start +node and going to G the goal node that's + + align:start position:0% +node and going to G the goal node that's + + + align:start position:0% +node and going to G the goal node that's +a standard notation but make sure that + + align:start position:0% +a standard notation but make sure that + + + align:start position:0% +a standard notation but make sure that +when you're taking the test you check to + + align:start position:0% +when you're taking the test you check to + + + align:start position:0% +when you're taking the test you check to +make sure where the start Noe is where + + align:start position:0% +make sure where the start Noe is where + + + align:start position:0% +make sure where the start Noe is where +the goal Noe is it's pretty pretty much + + align:start position:0% +the goal Noe is it's pretty pretty much + + + align:start position:0% +the goal Noe is it's pretty pretty much +a a an move to have a g node + + align:start position:0% +a a an move to have a g node + + + align:start position:0% +a a an move to have a g node +that isn't the goal node but sometimes + + align:start position:0% +that isn't the goal node but sometimes + + + align:start position:0% +that isn't the goal node but sometimes +there won't be an S node that's a pretty + + align:start position:0% +there won't be an S node that's a pretty + + + align:start position:0% +there won't be an S node that's a pretty +good clue that something else is the + + align:start position:0% +good clue that something else is the + + + align:start position:0% +good clue that something else is the +start node now there's a few little + + align:start position:0% +start node now there's a few little + + + align:start position:0% +start node now there's a few little +white star ideas that we have or silver + + align:start position:0% +white star ideas that we have or silver + + + align:start position:0% +white star ideas that we have or silver +star ideas for search one is + + align:start position:0% +star ideas for search one is + + + align:start position:0% +star ideas for search one is +lexicography what is lexicography who + + align:start position:0% +lexicography what is lexicography who + + + align:start position:0% +lexicography what is lexicography who +cares well the most famous lexicographer + + align:start position:0% +cares well the most famous lexicographer + + + align:start position:0% +cares well the most famous lexicographer +I know of is Samuel Johnson who wrote a + + align:start position:0% +I know of is Samuel Johnson who wrote a + + + align:start position:0% +I know of is Samuel Johnson who wrote a +really famous dictionary and the only + + align:start position:0% +really famous dictionary and the only + + + align:start position:0% +really famous dictionary and the only +reason we care about it in this class is + + align:start position:0% +reason we care about it in this class is + + + align:start position:0% +reason we care about it in this class is +because you'll always see the + + align:start position:0% +because you'll always see the + + + align:start position:0% +because you'll always see the +instructions break ties and + + align:start position:0% +instructions break ties and + + + align:start position:0% +instructions break ties and +lexicographic Order and then you might + + align:start position:0% +lexicographic Order and then you might + + + align:start position:0% +lexicographic Order and then you might +be like wow that's really rather a wordy + + align:start position:0% +be like wow that's really rather a wordy + + + align:start position:0% +be like wow that's really rather a wordy +word uh or a cesop pelian word or + + align:start position:0% +word uh or a cesop pelian word or + + + align:start position:0% +word uh or a cesop pelian word or +whatever really long word you want to + + align:start position:0% +whatever really long word you want to + + + align:start position:0% +whatever really long word you want to +use to describe the word lexicographic + + align:start position:0% +use to describe the word lexicographic + + + align:start position:0% +use to describe the word lexicographic +what the heck does it mean basically it + + align:start position:0% +what the heck does it mean basically it + + + align:start position:0% +what the heck does it mean basically it +means alphabetical + + align:start position:0% +means alphabetical + + + align:start position:0% +means alphabetical +order like you would do in a + + align:start position:0% +order like you would do in a + + + align:start position:0% +order like you would do in a +dictionary so for instance + + align:start position:0% +dictionary so for instance + + + align:start position:0% +dictionary so for instance +in alphabetical order a comes from + + align:start position:0% +in alphabetical order a comes from + + + align:start position:0% +in alphabetical order a comes from +before B so you would go to a before B + + align:start position:0% +before B so you would go to a before B + + + align:start position:0% +before B so you would go to a before B +now even beyond that point there's + + align:start position:0% +now even beyond that point there's + + + align:start position:0% +now even beyond that point there's +several ways to do lexicographic + + align:start position:0% +several ways to do lexicographic + + + align:start position:0% +several ways to do lexicographic +tiebreak and it's not always consistent + + align:start position:0% +tiebreak and it's not always consistent + + + align:start position:0% +tiebreak and it's not always consistent +between algorithms how you would do + + align:start position:0% +between algorithms how you would do + + + align:start position:0% +between algorithms how you would do +lexic graphic tiebreak in the most + + align:start position:0% +lexic graphic tiebreak in the most + + + align:start position:0% +lexic graphic tiebreak in the most +recent time that Patrick was kind of + + align:start position:0% +recent time that Patrick was kind of + + + align:start position:0% +recent time that Patrick was kind of +randomly talking to the staff he made it + + align:start position:0% +randomly talking to the staff he made it + + + align:start position:0% +randomly talking to the staff he made it +clear that the way he would like us to + + align:start position:0% +clear that the way he would like us to + + + align:start position:0% +clear that the way he would like us to +do it and therefore the way we' like you + + align:start position:0% +do it and therefore the way we' like you + + + align:start position:0% +do it and therefore the way we' like you +to do it is to tiebreak based on the + + align:start position:0% +to do it is to tiebreak based on the + + + align:start position:0% +to do it is to tiebreak based on the +very latest nodes at the end so you + + align:start position:0% +very latest nodes at the end so you + + + align:start position:0% +very latest nodes at the end so you +might say that's not really lexical + + align:start position:0% +might say that's not really lexical + + + align:start position:0% +might say that's not really lexical +graphic wouldn't sa come before s GA in + + align:start position:0% +graphic wouldn't sa come before s GA in + + + align:start position:0% +graphic wouldn't sa come before s GA in +the + + align:start position:0% +the + + + align:start position:0% +the +dictionary + + align:start position:0% +dictionary + + + align:start position:0% +dictionary +um and my answer my my answer to you is + + align:start position:0% +um and my answer my my answer to you is + + + align:start position:0% +um and my answer my my answer to you is +yes it + + align:start position:0% + + + + align:start position:0% + +would yes yes it definitely + + align:start position:0% +would yes yes it definitely + + + align:start position:0% +would yes yes it definitely +would however + + align:start position:0% +would however + + + align:start position:0% +would however +um that is um that that is apparently + + align:start position:0% +um that is um that that is apparently + + + align:start position:0% +um that is um that that is apparently +what we're doing according to the last + + align:start position:0% +what we're doing according to the last + + + align:start position:0% +what we're doing according to the last +thing that Patrick said and we will keep + + align:start position:0% +thing that Patrick said and we will keep + + + align:start position:0% +thing that Patrick said and we will keep +you updated if um he decides to go back + + align:start position:0% +you updated if um he decides to go back + + + align:start position:0% +you updated if um he decides to go back +to dictionary order + + align:start position:0% +to dictionary order + + + align:start position:0% +to dictionary order +so um that's lexicographic lexicography + + align:start position:0% +so um that's lexicographic lexicography + + + align:start position:0% +so um that's lexicographic lexicography +you might be wondering what the picture + + align:start position:0% +you might be wondering what the picture + + + align:start position:0% +you might be wondering what the picture +here is well this is our friend the Ora + + align:start position:0% +here is well this is our friend the Ora + + + align:start position:0% +here is well this is our friend the Ora +Boris long has it been a symbol in + + align:start position:0% +Boris long has it been a symbol in + + + align:start position:0% +Boris long has it been a symbol in +alchemy of infinity eternity or maybe + + align:start position:0% +alchemy of infinity eternity or maybe + + + align:start position:0% +alchemy of infinity eternity or maybe +you know a um sort of infinite energy + + align:start position:0% +you know a um sort of infinite energy + + + align:start position:0% +you know a um sort of infinite energy +engine turning iron into gold but today + + align:start position:0% +engine turning iron into gold but today + + + align:start position:0% +engine turning iron into gold but today +unfortunately the orar is endangered + + align:start position:0% +unfortunately the orar is endangered + + + align:start position:0% +unfortunately the orar is endangered +species because + + align:start position:0% + + + + align:start position:0% + +no biting your own tail in + + align:start position:0% +no biting your own tail in + + + align:start position:0% +no biting your own tail in +6034 a lot of people mess up from this + + align:start position:0% +6034 a lot of people mess up from this + + + align:start position:0% +6034 a lot of people mess up from this +it's an honest mistake I mean we've + + align:start position:0% +it's an honest mistake I mean we've + + + align:start position:0% +it's an honest mistake I mean we've +gotten some emails from staff members + + align:start position:0% +gotten some emails from staff members + + + align:start position:0% +gotten some emails from staff members +who um couldn't solve one of the + + align:start position:0% +who um couldn't solve one of the + + + align:start position:0% +who um couldn't solve one of the +problems because they forgot about this + + align:start position:0% +problems because they forgot about this + + + align:start position:0% +problems because they forgot about this +so it's okay if you forget but try your + + align:start position:0% +so it's okay if you forget but try your + + + align:start position:0% +so it's okay if you forget but try your +best to remember nobody in your own tell + + align:start position:0% +best to remember nobody in your own tell + + + align:start position:0% +best to remember nobody in your own tell +is the only smart thing our system does + + align:start position:0% +is the only smart thing our system does + + + align:start position:0% +is the only smart thing our system does +you'll remember last week when we were + + align:start position:0% +you'll remember last week when we were + + + align:start position:0% +you'll remember last week when we were +talking about rules and we were saying + + align:start position:0% +talking about rules and we were saying + + + align:start position:0% +talking about rules and we were saying +that the rule system is not a smart + + align:start position:0% +that the rule system is not a smart + + + align:start position:0% +that the rule system is not a smart +creature it doesn't know that there's + + align:start position:0% +creature it doesn't know that there's + + + align:start position:0% +creature it doesn't know that there's +diff there's difference between or sorry + + align:start position:0% +diff there's difference between or sorry + + + align:start position:0% +diff there's difference between or sorry +it doesn't know that not poly is dead + + align:start position:0% +it doesn't know that not poly is dead + + + align:start position:0% +it doesn't know that not poly is dead +should be the same as poly is not dead + + align:start position:0% +should be the same as poly is not dead + + + align:start position:0% +should be the same as poly is not dead +or something like that it's too dumb to + + align:start position:0% +or something like that it's too dumb to + + + align:start position:0% +or something like that it's too dumb to +figure that out well this system is also + + align:start position:0% +figure that out well this system is also + + + align:start position:0% +figure that out well this system is also +dumb but one thing it knows is that + + align:start position:0% +dumb but one thing it knows is that + + + align:start position:0% +dumb but one thing it knows is that +Patrick really hates if the same node + + align:start position:0% +Patrick really hates if the same node + + + align:start position:0% +Patrick really hates if the same node +appears twice within the same path and + + align:start position:0% +appears twice within the same path and + + + align:start position:0% +appears twice within the same path and +it will destroy that immediately before + + align:start position:0% +it will destroy that immediately before + + + align:start position:0% +it will destroy that immediately before +even adding it to the que it's gone it's + + align:start position:0% +even adding it to the que it's gone it's + + + align:start position:0% +even adding it to the que it's gone it's +not considered it's out of there so very + + align:start position:0% +not considered it's out of there so very + + + align:start position:0% +not considered it's out of there so very +important sad or Bor no biting your own + + align:start position:0% +important sad or Bor no biting your own + + + align:start position:0% +important sad or Bor no biting your own +tail all right so now that I've gotten + + align:start position:0% +tail all right so now that I've gotten + + + align:start position:0% +tail all right so now that I've gotten +through that let's actually solve the + + align:start position:0% +through that let's actually solve the + + + align:start position:0% +through that let's actually solve the +problem with some depth first search how + + align:start position:0% +problem with some depth first search how + + + align:start position:0% +problem with some depth first search how +will we do that while we're not going to + + align:start position:0% +will we do that while we're not going to + + + align:start position:0% +will we do that while we're not going to +use the Q at popular demand we're going + + align:start position:0% +use the Q at popular demand we're going + + + align:start position:0% +use the Q at popular demand we're going +to use a gold tree so we'll start at + + align:start position:0% +to use a gold tree so we'll start at + + + align:start position:0% +to use a gold tree so we'll start at +node + + align:start position:0% +node + + + align:start position:0% +node +s what do our choices at node + + align:start position:0% +s what do our choices at node + + + align:start position:0% +s what do our choices at node +s well I'm going to force you guys to + + align:start position:0% +s well I'm going to force you guys to + + + align:start position:0% +s well I'm going to force you guys to +help so it won't be quite as fast but it + + align:start position:0% +help so it won't be quite as fast but it + + + align:start position:0% +help so it won't be quite as fast but it +will be fun so what are choice at node + + align:start position:0% +will be fun so what are choice at node + + + align:start position:0% +will be fun so what are choice at node +s you not behind you me yes um A or B + + align:start position:0% +s you not behind you me yes um A or B + + + align:start position:0% +s you not behind you me yes um A or B +not quite and this is something I like + + align:start position:0% +not quite and this is something I like + + + align:start position:0% +not quite and this is something I like +about this problem you got most of them + + align:start position:0% +about this problem you got most of them + + + align:start position:0% +about this problem you got most of them +do you see that there might be another + + align:start position:0% +do you see that there might be another + + + align:start position:0% +do you see that there might be another +Choice everyone yes see this is a big + + align:start position:0% +Choice everyone yes see this is a big + + + align:start position:0% +Choice everyone yes see this is a big +problem that has happened on a few + + align:start position:0% +problem that has happened on a few + + + align:start position:0% +problem that has happened on a few +different quiz problems where there's a + + align:start position:0% +different quiz problems where there's a + + + align:start position:0% +different quiz problems where there's a +tree that you could where there's a sort + + align:start position:0% +tree that you could where there's a sort + + + align:start position:0% +tree that you could where there's a sort +of a grid that looks like a tree or + + align:start position:0% +of a grid that looks like a tree or + + + align:start position:0% +of a grid that looks like a tree or +graph that looks like a tree where + + align:start position:0% +graph that looks like a tree where + + + align:start position:0% +graph that looks like a tree where +people um aren't as willing to go up as + + align:start position:0% +people um aren't as willing to go up as + + + align:start position:0% +people um aren't as willing to go up as +they are to go down you can see it on + + align:start position:0% +they are to go down you can see it on + + + align:start position:0% +they are to go down you can see it on +some of the other past P problems too + + align:start position:0% +some of the other past P problems too + + + align:start position:0% +some of the other past P problems too +make sure that you check the + + align:start position:0% +make sure that you check the + + + align:start position:0% +make sure that you check the +connectivity and also note that unless + + align:start position:0% +connectivity and also note that unless + + + align:start position:0% +connectivity and also note that unless +otherwise specified and I don't think + + align:start position:0% +otherwise specified and I don't think + + + align:start position:0% +otherwise specified and I don't think +we've really done this much + + align:start position:0% +we've really done this much + + + align:start position:0% +we've really done this much +the little um connecting edges in our + + align:start position:0% +the little um connecting edges in our + + + align:start position:0% +the little um connecting edges in our +graphs are bir directional you'll see a + + align:start position:0% +graphs are bir directional you'll see a + + + align:start position:0% +graphs are bir directional you'll see a +big arrow and probably instructions + + align:start position:0% +big arrow and probably instructions + + + align:start position:0% +big arrow and probably instructions +written at least eight font sizes is + + align:start position:0% +written at least eight font sizes is + + + align:start position:0% +written at least eight font sizes is +higher than all the rest of them and + + align:start position:0% +higher than all the rest of them and + + + align:start position:0% +higher than all the rest of them and +bold if um if we're going to do + + align:start position:0% +bold if um if we're going to do + + + align:start position:0% +bold if um if we're going to do +something different for this quiz it + + align:start position:0% +something different for this quiz it + + + align:start position:0% +something different for this quiz it +happens that they do it sometimes while + + align:start position:0% +happens that they do it sometimes while + + + align:start position:0% +happens that they do it sometimes while +I was just say mega reation we never do + + align:start position:0% +I was just say mega reation we never do + + + align:start position:0% +I was just say mega reation we never do +this and then on the quiz they do it but + + align:start position:0% +this and then on the quiz they do it but + + + align:start position:0% +this and then on the quiz they do it but +it will be in giant letters which also + + align:start position:0% +it will be in giant letters which also + + + align:start position:0% +it will be in giant letters which also +leads me to another SilverStar idea that + + align:start position:0% +leads me to another SilverStar idea that + + + align:start position:0% +leads me to another SilverStar idea that +I forgot to tell you guys last week so I + + align:start position:0% +I forgot to tell you guys last week so I + + + align:start position:0% +I forgot to tell you guys last week so I +hope people didn't ditch out on me like + + align:start position:0% +hope people didn't ditch out on me like + + + align:start position:0% +hope people didn't ditch out on me like +oh Mark's boring we won't come next week + + align:start position:0% +oh Mark's boring we won't come next week + + + align:start position:0% +oh Mark's boring we won't come next week +and then missed this one because it just + + align:start position:0% +and then missed this one because it just + + + align:start position:0% +and then missed this one because it just +came to my mind that is read the + + align:start position:0% +came to my mind that is read the + + + align:start position:0% +came to my mind that is read the +instructions is a very important thing + + align:start position:0% +instructions is a very important thing + + + align:start position:0% +instructions is a very important thing +for the quizzes and uh Patrick will in a + + align:start position:0% +for the quizzes and uh Patrick will in a + + + align:start position:0% +for the quizzes and uh Patrick will in a +later lecture tell you guys ask why five + + align:start position:0% +later lecture tell you guys ask why five + + + align:start position:0% +later lecture tell you guys ask why five +times and he'll explain why that's a + + align:start position:0% +times and he'll explain why that's a + + + align:start position:0% +times and he'll explain why that's a +gold star idea my parallel to this is + + align:start position:0% +gold star idea my parallel to this is + + + align:start position:0% +gold star idea my parallel to this is +read the instructions five times maybe + + align:start position:0% +read the instructions five times maybe + + + align:start position:0% +read the instructions five times maybe +not five maybe three or four but at + + align:start position:0% +not five maybe three or four but at + + + align:start position:0% +not five maybe three or four but at +least three read the instructions read + + align:start position:0% +least three read the instructions read + + + align:start position:0% +least three read the instructions read +them again then read them a third time + + align:start position:0% +them again then read them a third time + + + align:start position:0% +them again then read them a third time +only paying attention to whatever is + + align:start position:0% +only paying attention to whatever is + + + align:start position:0% +only paying attention to whatever is +bold and eight sizes larger than all the + + align:start position:0% +bold and eight sizes larger than all the + + + align:start position:0% +bold and eight sizes larger than all the +other ones because there's going to be + + align:start position:0% +other ones because there's going to be + + + align:start position:0% +other ones because there's going to be +something there that's that size and + + align:start position:0% +something there that's that size and + + + align:start position:0% +something there that's that size and +it's going to be the one that thing that + + align:start position:0% +it's going to be the one that thing that + + + align:start position:0% +it's going to be the one that thing that +everyone misses so make sure you're not + + align:start position:0% +everyone misses so make sure you're not + + + align:start position:0% +everyone misses so make sure you're not +everyone and you read the instructions a + + align:start position:0% +everyone and you read the instructions a + + + align:start position:0% +everyone and you read the instructions a +lot of times but anyway so yeah we've + + align:start position:0% +lot of times but anyway so yeah we've + + + align:start position:0% +lot of times but anyway so yeah we've +got it right s goes to a b and + + align:start position:0% +got it right s goes to a b and + + + align:start position:0% +got it right s goes to a b and +c + + align:start position:0% +c + + + align:start position:0% +c +okay we're looking at a B and C as + + align:start position:0% +okay we're looking at a B and C as + + + align:start position:0% +okay we're looking at a B and C as +possibilities everyone let help we make + + align:start position:0% +possibilities everyone let help we make + + + align:start position:0% +possibilities everyone let help we make +the Le graphic tie bre where do we go a + + align:start position:0% +the Le graphic tie bre where do we go a + + + align:start position:0% +the Le graphic tie bre where do we go a +that's + + align:start position:0% +that's + + + align:start position:0% +that's +right all right actually you know what + + align:start position:0% +right all right actually you know what + + + align:start position:0% +right all right actually you know what +I'll call on you guys for I'll call you + + align:start position:0% +I'll call on you guys for I'll call you + + + align:start position:0% +I'll call on you guys for I'll call you +guys for other ones but depth for + + align:start position:0% +guys for other ones but depth for + + + align:start position:0% +guys for other ones but depth for +service is pretty simple we can have + + align:start position:0% +service is pretty simple we can have + + + align:start position:0% +service is pretty simple we can have +everyone do it together a everyone a + + align:start position:0% +everyone do it together a everyone a + + + align:start position:0% +everyone do it together a everyone a +only leads to that's right why doesn't + + align:start position:0% +only leads to that's right why doesn't + + + align:start position:0% +only leads to that's right why doesn't +lead to S as + + align:start position:0% +lead to S as + + + align:start position:0% +lead to S as +well no biting your own tail everyone's + + align:start position:0% +well no biting your own tail everyone's + + + align:start position:0% +well no biting your own tail everyone's +right good job everyone all right s + + align:start position:0% +right good job everyone all right s + + + align:start position:0% +right good job everyone all right s +leads to a s leads to these three you go + + align:start position:0% +leads to a s leads to these three you go + + + align:start position:0% +leads to a s leads to these three you go +to a go to D oh dead + + align:start position:0% +to a go to D oh dead + + + align:start position:0% +to a go to D oh dead +and backtrack okay when we backtrack we + + align:start position:0% +and backtrack okay when we backtrack we + + + align:start position:0% +and backtrack okay when we backtrack we +had backtrack up to a there's no other + + align:start position:0% +had backtrack up to a there's no other + + + align:start position:0% +had backtrack up to a there's no other +children we backtrack up to S where we + + align:start position:0% +children we backtrack up to S where we + + + align:start position:0% +children we backtrack up to S where we +go now B it's the next one + + align:start position:0% +go now B it's the next one + + + align:start position:0% +go now B it's the next one +alphabetically all right B can't go to S + + align:start position:0% +alphabetically all right B can't go to S + + + align:start position:0% +alphabetically all right B can't go to S +so it only goes to yes one more at H we + + align:start position:0% +so it only goes to yes one more at H we + + + align:start position:0% +so it only goes to yes one more at H we +can go + + align:start position:0% +can go + + + align:start position:0% +can go +to f or i that's right you guys get it + + align:start position:0% +to f or i that's right you guys get it + + + align:start position:0% +to f or i that's right you guys get it +this dep for search is easy all right so + + align:start position:0% +this dep for search is easy all right so + + + align:start position:0% +this dep for search is easy all right so +but we + + align:start position:0% +but we + + + align:start position:0% +but we +choose F that's right when we F we can + + align:start position:0% +choose F that's right when we F we can + + + align:start position:0% +choose F that's right when we F we can +go to + + align:start position:0% +go to + + + align:start position:0% +go to +to e and J that's right we'll choose E + + align:start position:0% +to e and J that's right we'll choose E + + + align:start position:0% +to e and J that's right we'll choose E +when we're at e we can go + + align:start position:0% +when we're at e we can go + + + align:start position:0% +when we're at e we can go +to we uh we we can go to C it's not on + + align:start position:0% +to we uh we we can go to C it's not on + + + align:start position:0% +to we uh we we can go to C it's not on +this particular path people are correct + + align:start position:0% +this particular path people are correct + + + align:start position:0% +this particular path people are correct +when they say C when we go to C we can + + align:start position:0% +when they say C when we go to C we can + + + align:start position:0% +when they say C when we go to C we can +go to nowhere we're dead backtrack we + + align:start position:0% +go to nowhere we're dead backtrack we + + + align:start position:0% +go to nowhere we're dead backtrack we +backtrack uh we we can't do anything e + + align:start position:0% +backtrack uh we we can't do anything e + + + align:start position:0% +backtrack uh we we can't do anything e +we go to F now I forgot to tell you guys + + align:start position:0% +we go to F now I forgot to tell you guys + + + align:start position:0% +we go to F now I forgot to tell you guys +but this is an important note someone's + + align:start position:0% +but this is an important note someone's + + + align:start position:0% +but this is an important note someone's +going to get this wrong it's going to be + + align:start position:0% +going to get this wrong it's going to be + + + align:start position:0% +going to get this wrong it's going to be +one of you look around you all through + + align:start position:0% +one of you look around you all through + + + align:start position:0% +one of you look around you all through +the room at least one of you is going to + + align:start position:0% +the room at least one of you is going to + + + align:start position:0% +the room at least one of you is going to +do this so now I'm going to tell you not + + align:start position:0% +do this so now I'm going to tell you not + + + align:start position:0% +do this so now I'm going to tell you not +to do this and then hopefully that will + + align:start position:0% +to do this and then hopefully that will + + + align:start position:0% +to do this and then hopefully that will +still be true but for fewer people when + + align:start position:0% +still be true but for fewer people when + + + align:start position:0% +still be true but for fewer people when +I went to D and then I backtracked and I + + align:start position:0% +I went to D and then I backtracked and I + + + align:start position:0% +I went to D and then I backtracked and I +went to ask how many times did I + + align:start position:0% +went to ask how many times did I + + + align:start position:0% +went to ask how many times did I +backtrack + + align:start position:0% +backtrack + + + align:start position:0% +backtrack +once I backtracked once this would have + + align:start position:0% +once I backtracked once this would have + + + align:start position:0% +once I backtracked once this would have +been more obvious if we were doing the + + align:start position:0% +been more obvious if we were doing the + + + align:start position:0% +been more obvious if we were doing the +really slow boring agenda way with or Q + + align:start position:0% +really slow boring agenda way with or Q + + + align:start position:0% +really slow boring agenda way with or Q +way um because when we got to + + align:start position:0% +way um because when we got to + + + align:start position:0% +way um because when we got to +sad and we expanded it and there was + + align:start position:0% +sad and we expanded it and there was + + + align:start position:0% +sad and we expanded it and there was +nothing left we throw it off the top of + + align:start position:0% +nothing left we throw it off the top of + + + align:start position:0% +nothing left we throw it off the top of +the queue and go to the next thing on + + align:start position:0% +the queue and go to the next thing on + + + align:start position:0% +the queue and go to the next thing on +the Queue and it turns out the next + + align:start position:0% +the Queue and it turns out the next + + + align:start position:0% +the Queue and it turns out the next +thing on the que is SB that step was + + align:start position:0% +thing on the que is SB that step was + + + align:start position:0% +thing on the que is SB that step was +only taken once it since we're using the + + align:start position:0% +only taken once it since we're using the + + + align:start position:0% +only taken once it since we're using the +gold tree which is faster it looked like + + align:start position:0% +gold tree which is faster it looked like + + + align:start position:0% +gold tree which is faster it looked like +we did two but we didn't and if you use + + align:start position:0% +we did two but we didn't and if you use + + + align:start position:0% +we did two but we didn't and if you use +the que you'll see that because it'll go + + align:start position:0% +the que you'll see that because it'll go + + + align:start position:0% +the que you'll see that because it'll go +s and then we expend that sbsc okay we + + align:start position:0% +s and then we expend that sbsc okay we + + + align:start position:0% +s and then we expend that sbsc okay we +spend sa sad sbsc we spend s it's dead + + align:start position:0% +spend sa sad sbsc we spend s it's dead + + + align:start position:0% +spend sa sad sbsc we spend s it's dead +sbsc one back track we're back at spe so + + align:start position:0% +sbsc one back track we're back at spe so + + + align:start position:0% +sbsc one back track we're back at spe so +so far we've done two not four see I + + align:start position:0% +so far we've done two not four see I + + + align:start position:0% +so far we've done two not four see I +mean it's pretty intuitive to say that + + align:start position:0% +mean it's pretty intuitive to say that + + + align:start position:0% +mean it's pretty intuitive to say that +you did two there it turns out you + + align:start position:0% +you did two there it turns out you + + + align:start position:0% +you did two there it turns out you +didn't because of the algorith the + + align:start position:0% +didn't because of the algorith the + + + align:start position:0% +didn't because of the algorith the +algorithm that's backing what lets us do + + align:start position:0% +algorithm that's backing what lets us do + + + align:start position:0% +algorithm that's backing what lets us do +this gold tree search so make uh try to + + align:start position:0% +this gold tree search so make uh try to + + + align:start position:0% +this gold tree search so make uh try to +make sure you're not the one who says + + align:start position:0% +make sure you're not the one who says + + + align:start position:0% +make sure you're not the one who says +two well and we and I on the other hand + + align:start position:0% +two well and we and I on the other hand + + + align:start position:0% +two well and we and I on the other hand +we'll try to make sure that we don't + + align:start position:0% +we'll try to make sure that we don't + + + align:start position:0% +we'll try to make sure that we don't +take off too many points if you do + + align:start position:0% +take off too many points if you do + + + align:start position:0% +take off too many points if you do +question + + align:start position:0% + + + + align:start position:0% + +how much it + + align:start position:0% +how much it + + + align:start position:0% +how much it +chains any backtracking is just + + align:start position:0% +chains any backtracking is just + + + align:start position:0% +chains any backtracking is just +considered once is always going to be + + align:start position:0% +considered once is always going to be + + + align:start position:0% +considered once is always going to be +considered one + + align:start position:0% +considered one + + + align:start position:0% +considered one +step it's possible to backstrap two + + align:start position:0% +step it's possible to backstrap two + + + align:start position:0% +step it's possible to backstrap two +times in a row like if s if B didn't go + + align:start position:0% +times in a row like if s if B didn't go + + + align:start position:0% +times in a row like if s if B didn't go +to anything instead of going to H then + + align:start position:0% +to anything instead of going to H then + + + align:start position:0% +to anything instead of going to H then +we might backtrack twice before we got + + align:start position:0% +we might backtrack twice before we got + + + align:start position:0% +we might backtrack twice before we got +to SC generally anytime you draw a + + align:start position:0% +to SC generally anytime you draw a + + + align:start position:0% +to SC generally anytime you draw a +swizzle if you're like me and you draw a + + align:start position:0% +swizzle if you're like me and you draw a + + + align:start position:0% +swizzle if you're like me and you draw a +swizzle I suggest the Swizzles they're + + align:start position:0% +swizzle I suggest the Swizzles they're + + + align:start position:0% +swizzle I suggest the Swizzles they're +very nice little things but if anytime + + align:start position:0% +very nice little things but if anytime + + + align:start position:0% +very nice little things but if anytime +you draw a swizzle on your graph you've + + align:start position:0% +you draw a swizzle on your graph you've + + + align:start position:0% +you draw a swizzle on your graph you've +backtracked once you could even write BT + + align:start position:0% +backtracked once you could even write BT + + + align:start position:0% +backtracked once you could even write BT +next to the Swizzle and go back and + + align:start position:0% +next to the Swizzle and go back and + + + align:start position:0% +next to the Swizzle and go back and +count those or even just count the + + align:start position:0% +count those or even just count the + + + align:start position:0% +count those or even just count the +Swizzles at the end you've got it you + + align:start position:0% +Swizzles at the end you've got it you + + + align:start position:0% +Swizzles at the end you've got it you +got the answer because they often ask + + align:start position:0% +got the answer because they often ask + + + align:start position:0% +got the answer because they often ask +how many times have you + + align:start position:0% + + + + align:start position:0% + +backtracked all right so good questions + + align:start position:0% +backtracked all right so good questions + + + align:start position:0% +backtracked all right so good questions +everyone so anyway we backtrack from C + + align:start position:0% +everyone so anyway we backtrack from C + + + align:start position:0% +everyone so anyway we backtrack from C +nothing e we got back we we at F so we + + align:start position:0% +nothing e we got back we we at F so we + + + align:start position:0% +nothing e we got back we we at F so we +at + + align:start position:0% +at + + + align:start position:0% +at +sbhf we go to J it's the only choice at + + align:start position:0% +sbhf we go to J it's the only choice at + + + align:start position:0% +sbhf we go to J it's the only choice at +J we can only go to and at I we can only + + align:start position:0% +J we can only go to and at I we can only + + + align:start position:0% +J we can only go to and at I we can only +go to and we win it's not an optimal + + align:start position:0% +go to and we win it's not an optimal + + + align:start position:0% +go to and we win it's not an optimal +search so as soon as we see anything + + align:start position:0% +search so as soon as we see anything + + + align:start position:0% +search so as soon as we see anything +with the G on the Q boom + + align:start position:0% +with the G on the Q boom + + + align:start position:0% +with the G on the Q boom +winner all right and we're done we did + + align:start position:0% +winner all right and we're done we did + + + align:start position:0% +winner all right and we're done we did +it that wasn't too bad for those of you + + align:start position:0% +it that wasn't too bad for those of you + + + align:start position:0% +it that wasn't too bad for those of you +who are vaguely interested in seeing how + + align:start position:0% +who are vaguely interested in seeing how + + + align:start position:0% +who are vaguely interested in seeing how +I would do it um the really super fast + + align:start position:0% +I would do it um the really super fast + + + align:start position:0% +I would do it um the really super fast +way it goes something like this all + + align:start position:0% +way it goes something like this all + + + align:start position:0% +way it goes something like this all +right ABC a comes first only D + + align:start position:0% +right ABC a comes first only D + + + align:start position:0% +right ABC a comes first only D +backtrack all right B comes first h f + + align:start position:0% +backtrack all right B comes first h f + + + align:start position:0% +backtrack all right B comes first h f +comes first e c nothing backtrack + + align:start position:0% +comes first e c nothing backtrack + + + align:start position:0% +comes first e c nothing backtrack +uh we came that way j i + + align:start position:0% +uh we came that way j i + + + align:start position:0% +uh we came that way j i +g so that's the really fast way to do + + align:start position:0% +g so that's the really fast way to do + + + align:start position:0% +g so that's the really fast way to do +depth resarch don't do that kids we + + align:start position:0% +depth resarch don't do that kids we + + + align:start position:0% +depth resarch don't do that kids we +don't like uh well maybe you can if you + + align:start position:0% +don't like uh well maybe you can if you + + + align:start position:0% +don't like uh well maybe you can if you +get it right we're not going to take off + + align:start position:0% +get it right we're not going to take off + + + align:start position:0% +get it right we're not going to take off +we're not going to take off points + + align:start position:0% +we're not going to take off points + + + align:start position:0% +we're not going to take off points +usually generally when we say draw the + + align:start position:0% +usually generally when we say draw the + + + align:start position:0% +usually generally when we say draw the +gold tree below it's to assign partial + + align:start position:0% +gold tree below it's to assign partial + + + align:start position:0% +gold tree below it's to assign partial +credit however we are pretty strict + + align:start position:0% +credit however we are pretty strict + + + align:start position:0% +credit however we are pretty strict +about that if anything is wrong except + + align:start position:0% +about that if anything is wrong except + + + align:start position:0% +about that if anything is wrong except +for maybe like okay you write everything + + align:start position:0% +for maybe like okay you write everything + + + align:start position:0% +for maybe like okay you write everything +exactly right and forget G at the end if + + align:start position:0% +exactly right and forget G at the end if + + + align:start position:0% +exactly right and forget G at the end if +anything that's not completely + + align:start position:0% +anything that's not completely + + + align:start position:0% +anything that's not completely +understandable is wrong you will + + align:start position:0% +understandable is wrong you will + + + align:start position:0% +understandable is wrong you will +probably lose all of the points and it + + align:start position:0% +probably lose all of the points and it + + + align:start position:0% +probably lose all of the points and it +will be a lot of points if you don't + + align:start position:0% +will be a lot of points if you don't + + + align:start position:0% +will be a lot of points if you don't +draw the gold tree so may I will + + align:start position:0% +draw the gold tree so may I will + + + align:start position:0% +draw the gold tree so may I will +emphasize drawing the gold tree is a + + align:start position:0% +emphasize drawing the gold tree is a + + + align:start position:0% +emphasize drawing the gold tree is a +good + + align:start position:0% +good + + + align:start position:0% +good +idea all right so now let's do a breath + + align:start position:0% +idea all right so now let's do a breath + + + align:start position:0% +idea all right so now let's do a breath +first + + align:start position:0% +first + + + align:start position:0% +first +search before we do the breath res + + align:start position:0% +search before we do the breath res + + + align:start position:0% +search before we do the breath res +search on this on this tree I will tell + + align:start position:0% +search on this on this tree I will tell + + + align:start position:0% +search on this on this tree I will tell +you guys that there is also a fast way + + align:start position:0% +you guys that there is also a fast way + + + align:start position:0% +you guys that there is also a fast way +to do the breath first search Which is + + align:start position:0% +to do the breath first search Which is + + + align:start position:0% +to do the breath first search Which is +less risky and it really depends on how + + align:start position:0% +less risky and it really depends on how + + + align:start position:0% +less risky and it really depends on how +nice they are about what they ask for in + + align:start position:0% +nice they are about what they ask for in + + + align:start position:0% +nice they are about what they ask for in +this case the breath first search + + align:start position:0% +this case the breath first search + + + align:start position:0% +this case the breath first search +question asks what path does Mark find + + align:start position:0% +question asks what path does Mark find + + + align:start position:0% +question asks what path does Mark find +using breath first search rather than + + align:start position:0% +using breath first search rather than + + + align:start position:0% +using breath first search rather than +saying what nodes does he expand in + + align:start position:0% +saying what nodes does he expand in + + + align:start position:0% +saying what nodes does he expand in +order or anything like that that is + + align:start position:0% +order or anything like that that is + + + align:start position:0% +order or anything like that that is +important if that question is asked you + + align:start position:0% +important if that question is asked you + + + align:start position:0% +important if that question is asked you +there is a trick that will let you solve + + align:start position:0% +there is a trick that will let you solve + + + align:start position:0% +there is a trick that will let you solve +it very very quickly in fact faster than + + align:start position:0% +it very very quickly in fact faster than + + + align:start position:0% +it very very quickly in fact faster than +dep first search you can solve it by + + align:start position:0% +dep first search you can solve it by + + + align:start position:0% +dep first search you can solve it by +inspection at about 30 seconds does + + align:start position:0% +inspection at about 30 seconds does + + + align:start position:0% +inspection at about 30 seconds does +anyone know what the answer is what path + + align:start position:0% +anyone know what the answer is what path + + + align:start position:0% +anyone know what the answer is what path +did you + + align:start position:0% +did you + + + align:start position:0% +did you +find that's correct so the answer is + + align:start position:0% +find that's correct so the answer is + + + align:start position:0% +find that's correct so the answer is +on this graph the answer + + align:start position:0% + + + + align:start position:0% + +isbh that's the answer you would have + + align:start position:0% +isbh that's the answer you would have + + + align:start position:0% +isbh that's the answer you would have +your five + + align:start position:0% +your five + + + align:start position:0% +your five +points did people see that it doesn't + + align:start position:0% +points did people see that it doesn't + + + align:start position:0% +points did people see that it doesn't +always work so we're going to actually + + align:start position:0% +always work so we're going to actually + + + align:start position:0% +always work so we're going to actually +solve it but does everyone see that + + align:start position:0% +solve it but does everyone see that + + + align:start position:0% +solve it but does everyone see that +sometimes you can get away with not + + align:start position:0% +sometimes you can get away with not + + + align:start position:0% +sometimes you can get away with not +doing it because breath for search is + + align:start position:0% +doing it because breath for search is + + + align:start position:0% +doing it because breath for search is +guaranteed to give you the path as we + + align:start position:0% +guaranteed to give you the path as we + + + align:start position:0% +guaranteed to give you the path as we +heard correctly with the least number of + + align:start position:0% +heard correctly with the least number of + + + align:start position:0% +heard correctly with the least number of +jumps and if there more than one that + + align:start position:0% +jumps and if there more than one that + + + align:start position:0% +jumps and if there more than one that +tie with the least number of jumps you + + align:start position:0% +tie with the least number of jumps you + + + align:start position:0% +tie with the least number of jumps you +can just lexor graphically figure it out + + align:start position:0% +can just lexor graphically figure it out + + + align:start position:0% +can just lexor graphically figure it out +in this case with actual dictionary + + align:start position:0% +in this case with actual dictionary + + + align:start position:0% +in this case with actual dictionary +order + + align:start position:0% +order + + + align:start position:0% +order +but um sbig is the only one Let's do an + + align:start position:0% +but um sbig is the only one Let's do an + + + align:start position:0% +but um sbig is the only one Let's do an +actual breath first search though so we + + align:start position:0% +actual breath first search though so we + + + align:start position:0% +actual breath first search though so we +can feel better about + + align:start position:0% +can feel better about + + + align:start position:0% +can feel better about +ourselves okay + + align:start position:0% +ourselves okay + + + align:start position:0% +ourselves okay +so you've got S and S goes to as we saw + + align:start position:0% +so you've got S and S goes to as we saw + + + align:start position:0% +so you've got S and S goes to as we saw +before + + align:start position:0% +before + + + align:start position:0% +before +ABC maybe that doesn't have to go quite + + align:start position:0% +ABC maybe that doesn't have to go quite + + + align:start position:0% +ABC maybe that doesn't have to go quite +so + + align:start position:0% +so + + + align:start position:0% +so +high all right as we saw before s goes + + align:start position:0% +high all right as we saw before s goes + + + align:start position:0% +high all right as we saw before s goes +to + + align:start position:0% +to + + + align:start position:0% +to +ABC and you already told me that a goes + + align:start position:0% +ABC and you already told me that a goes + + + align:start position:0% +ABC and you already told me that a goes +to D and you told me that b goes to h + + align:start position:0% +to D and you told me that b goes to h + + + align:start position:0% +to D and you told me that b goes to h +but what does C Go + + align:start position:0% +but what does C Go + + + align:start position:0% +but what does C Go +to e that's right as you can see we're + + align:start position:0% +to e that's right as you can see we're + + + align:start position:0% +to e that's right as you can see we're +expanding it level by level left to + + align:start position:0% +expanding it level by level left to + + + align:start position:0% +expanding it level by level left to +right all right so + + align:start position:0% +right all right so + + + align:start position:0% +right all right so +sad where does sad go + + align:start position:0% +sad where does sad go + + + align:start position:0% +sad where does sad go +to sad goes to Nowhere it's dead sbh now + + align:start position:0% +to sad goes to Nowhere it's dead sbh now + + + align:start position:0% +to sad goes to Nowhere it's dead sbh now +wait you might say wait a minute Patrick + + align:start position:0% +wait you might say wait a minute Patrick + + + align:start position:0% +wait you might say wait a minute Patrick +said that we're using this weird + + align:start position:0% +said that we're using this weird + + + align:start position:0% +said that we're using this weird +dictionary order where E is at the end + + align:start position:0% +dictionary order where E is at the end + + + align:start position:0% +dictionary order where E is at the end +it comes before H that's our tiebreak + + align:start position:0% +it comes before H that's our tiebreak + + + align:start position:0% +it comes before H that's our tiebreak +order but it turns out that breath for + + align:start position:0% +order but it turns out that breath for + + + align:start position:0% +order but it turns out that breath for +search and depth for search don't sort + + align:start position:0% +search and depth for search don't sort + + + align:start position:0% +search and depth for search don't sort +in any way the um it's very important + + align:start position:0% +in any way the um it's very important + + + align:start position:0% +in any way the um it's very important +they don't sort the paths that are + + align:start position:0% +they don't sort the paths that are + + + align:start position:0% +they don't sort the paths that are +currently on the Queue so you're going + + align:start position:0% +currently on the Queue so you're going + + + align:start position:0% +currently on the Queue so you're going +to just go left to right left to right + + align:start position:0% +to just go left to right left to right + + + align:start position:0% +to just go left to right left to right +left to right and only at each node are + + align:start position:0% +left to right and only at each node are + + + align:start position:0% +left to right and only at each node are +you going to break ties in Lex's graphic + + align:start position:0% +you going to break ties in Lex's graphic + + + align:start position:0% +you going to break ties in Lex's graphic +order all right so sbh H goes to as we + + align:start position:0% +order all right so sbh H goes to as we + + + align:start position:0% +order all right so sbh H goes to as we +already know fni + + align:start position:0% + + + + align:start position:0% + +I E we think we already know but we + + align:start position:0% +I E we think we already know but we + + + align:start position:0% +I E we think we already know but we +don't quite because this is e coming + + align:start position:0% +don't quite because this is e coming + + + align:start position:0% +don't quite because this is e coming +from the other direction e this time + + align:start position:0% +from the other direction e this time + + + align:start position:0% +from the other direction e this time +goes to F that's right well actually you + + align:start position:0% +goes to F that's right well actually you + + + align:start position:0% +goes to F that's right well actually you +guys do already know it all right great + + align:start position:0% +guys do already know it all right great + + + align:start position:0% +guys do already know it all right great +now we come over here HF goes to as we + + align:start position:0% +now we come over here HF goes to as we + + + align:start position:0% +now we come over here HF goes to as we +already know e and + + align:start position:0% + + + + align:start position:0% + +j i goes to as we don't already know hi + + align:start position:0% +j i goes to as we don't already know hi + + + align:start position:0% +j i goes to as we don't already know hi +goes + + align:start position:0% +goes + + + align:start position:0% +goes +to G and J that's + + align:start position:0% + + + + align:start position:0% + +right and as it turns out by an + + align:start position:0% +right and as it turns out by an + + + align:start position:0% +right and as it turns out by an +implementation detail we're + + align:start position:0% + + + + align:start position:0% + +done question does it not expand EV at + + align:start position:0% +done question does it not expand EV at + + + align:start position:0% +done question does it not expand EV at +all now this is an implementation detail + + align:start position:0% +all now this is an implementation detail + + + align:start position:0% +all now this is an implementation detail +it's perfectly sane and reasonable to + + align:start position:0% +it's perfectly sane and reasonable to + + + align:start position:0% +it's perfectly sane and reasonable to +make a dep to breath first search that + + align:start position:0% +make a dep to breath first search that + + + align:start position:0% +make a dep to breath first search that +likes to finish its entire level that + + align:start position:0% +likes to finish its entire level that + + + align:start position:0% +likes to finish its entire level that +it's working on however in our + + align:start position:0% +it's working on however in our + + + align:start position:0% +it's working on however in our +implementation and we would have seen + + align:start position:0% +implementation and we would have seen + + + align:start position:0% +implementation and we would have seen +this if we had been pedantic and drawn + + align:start position:0% +this if we had been pedantic and drawn + + + align:start position:0% +this if we had been pedantic and drawn +out the entire queue it's another reason + + align:start position:0% +out the entire queue it's another reason + + + align:start position:0% +out the entire queue it's another reason +why drawing out the entire queue is as I + + align:start position:0% +why drawing out the entire queue is as I + + + align:start position:0% +why drawing out the entire queue is as I +said more reliable um in our + + align:start position:0% +said more reliable um in our + + + align:start position:0% +said more reliable um in our +implementation since it's not an optimal + + align:start position:0% +implementation since it's not an optimal + + + align:start position:0% +implementation since it's not an optimal +search as moment anywhere on the que you + + align:start position:0% +search as moment anywhere on the que you + + + align:start position:0% +search as moment anywhere on the que you +add something with a g at the end you + + align:start position:0% +add something with a g at the end you + + + align:start position:0% +add something with a g at the end you +finish and because of the fact that the + + align:start position:0% +finish and because of the fact that the + + + align:start position:0% +finish and because of the fact that the +way breath ver search does it's Mojo is + + align:start position:0% +way breath ver search does it's Mojo is + + + align:start position:0% +way breath ver search does it's Mojo is +that it adds everything to the end of + + align:start position:0% +that it adds everything to the end of + + + align:start position:0% +that it adds everything to the end of +the que that's how it does it level by + + align:start position:0% +the que that's how it does it level by + + + align:start position:0% +the que that's how it does it level by +level right it adds it to the end of the + + align:start position:0% +level right it adds it to the end of the + + + align:start position:0% +level right it adds it to the end of the +Q instead of the front well then you + + align:start position:0% +Q instead of the front well then you + + + align:start position:0% +Q instead of the front well then you +you'll add it to the end of the Q and + + align:start position:0% +you'll add it to the end of the Q and + + + align:start position:0% +you'll add it to the end of the Q and +then you will have it on the Q with a G + + align:start position:0% +then you will have it on the Q with a G + + + align:start position:0% +then you will have it on the Q with a G +so you won't have to do s + + align:start position:0% +so you won't have to do s + + + align:start position:0% +so you won't have to do s +CF uh another question + + align:start position:0% + + + + align:start position:0% + +um that's a good question so uh the + + align:start position:0% +um that's a good question so uh the + + + align:start position:0% +um that's a good question so uh the +question was so for the breath for + + align:start position:0% +question was so for the breath for + + + align:start position:0% +question was so for the breath for +search there was no backtracking d d + + align:start position:0% +search there was no backtracking d d + + + align:start position:0% +search there was no backtracking d d +died why didn't we backtrack or + + align:start position:0% +died why didn't we backtrack or + + + align:start position:0% +died why didn't we backtrack or +something the answer to that one is bre + + align:start position:0% +something the answer to that one is bre + + + align:start position:0% +something the answer to that one is bre +for breath first search backtracking + + align:start position:0% +for breath first search backtracking + + + align:start position:0% +for breath first search backtracking +doesn't really it isn't really a thing + + align:start position:0% +doesn't really it isn't really a thing + + + align:start position:0% +doesn't really it isn't really a thing +like it is for depth first search why + + align:start position:0% +like it is for depth first search why + + + align:start position:0% +like it is for depth first search why +well because breath first search we're + + align:start position:0% +well because breath first search we're + + + align:start position:0% +well because breath first search we're +sending our infinite monkeys down every + + align:start position:0% +sending our infinite monkeys down every + + + align:start position:0% +sending our infinite monkeys down every +path um in depth research we're really + + align:start position:0% +path um in depth research we're really + + + align:start position:0% +path um in depth research we're really +focused in N we're like we want to get + + align:start position:0% +focused in N we're like we want to get + + + align:start position:0% +focused in N we're like we want to get +there we want to get there ooh this way + + align:start position:0% +there we want to get there ooh this way + + + align:start position:0% +there we want to get there ooh this way +this way this way this way and we might + + align:start position:0% +this way this way this way and we might + + + align:start position:0% +this way this way this way and we might +have gone the wrong way and then we hit + + align:start position:0% +have gone the wrong way and then we hit + + + align:start position:0% +have gone the wrong way and then we hit +a dead end we're like oh crap and we go + + align:start position:0% +a dead end we're like oh crap and we go + + + align:start position:0% +a dead end we're like oh crap and we go +backwards but for for breath resarch + + align:start position:0% +backwards but for for breath resarch + + + align:start position:0% +backwards but for for breath resarch +we're we really are like an evil + + align:start position:0% +we're we really are like an evil + + + align:start position:0% +we're we really are like an evil +Overlord and you know we're like Mark + + align:start position:0% +Overlord and you know we're like Mark + + + align:start position:0% +Overlord and you know we're like Mark +Vader saying like Stormtroopers go every + + align:start position:0% +Vader saying like Stormtroopers go every + + + align:start position:0% +Vader saying like Stormtroopers go every +direction and then from there go every + + align:start position:0% +direction and then from there go every + + + align:start position:0% +direction and then from there go every +other direction and so even though yes + + align:start position:0% +other direction and so even though yes + + + align:start position:0% +other direction and so even though yes +when we got to D some of the + + align:start position:0% +when we got to D some of the + + + align:start position:0% +when we got to D some of the +Stormtroopers hit a dead end and + + align:start position:0% +Stormtroopers hit a dead end and + + + align:start position:0% +Stormtroopers hit a dead end and +probably like it was reflective and they + + align:start position:0% +probably like it was reflective and they + + + align:start position:0% +probably like it was reflective and they +shot it and hit themselves or something + + align:start position:0% +shot it and hit themselves or something + + + align:start position:0% +shot it and hit themselves or something +like that meanwhile the Stormtroopers be + + align:start position:0% +like that meanwhile the Stormtroopers be + + + align:start position:0% +like that meanwhile the Stormtroopers be +sent to B andc are still fine so we + + align:start position:0% +sent to B andc are still fine so we + + + align:start position:0% +sent to B andc are still fine so we +don't need to backtrack troops down yeah + + align:start position:0% +don't need to backtrack troops down yeah + + + align:start position:0% +don't need to backtrack troops down yeah +there are other troops going down the + + align:start position:0% +there are other troops going down the + + + align:start position:0% +there are other troops going down the +tree in every direction whereas in the + + align:start position:0% +tree in every direction whereas in the + + + align:start position:0% +tree in every direction whereas in the +def for search we only sent we're like + + align:start position:0% +def for search we only sent we're like + + + align:start position:0% +def for search we only sent we're like +there are definitely no Droids on this + + align:start position:0% +there are definitely no Droids on this + + + align:start position:0% +there are definitely no Droids on this +Escape pod send everyone this straight + + align:start position:0% +Escape pod send everyone this straight + + + align:start position:0% +Escape pod send everyone this straight +Direction and we only sent them to a and + + align:start position:0% +Direction and we only sent them to a and + + + align:start position:0% +Direction and we only sent them to a and +d and then so we had to back track + + align:start position:0% +d and then so we had to back track + + + align:start position:0% +d and then so we had to back track +because we hit a dead end does that make + + align:start position:0% +because we hit a dead end does that make + + + align:start position:0% +because we hit a dead end does that make +sense another + + align:start position:0% + + + + align:start position:0% + +question so the question is in this uh + + align:start position:0% +question so the question is in this uh + + + align:start position:0% +question so the question is in this uh +breath res search did LAX graphic order + + align:start position:0% +breath res search did LAX graphic order + + + align:start position:0% +breath res search did LAX graphic order +ever come into play the answer is yes in + + align:start position:0% +ever come into play the answer is yes in + + + align:start position:0% +ever come into play the answer is yes in +a very subtle and sneaky way which is um + + align:start position:0% +a very subtle and sneaky way which is um + + + align:start position:0% +a very subtle and sneaky way which is um +I wrote E before J F before I and G + + align:start position:0% +I wrote E before J F before I and G + + + align:start position:0% +I wrote E before J F before I and G +before + + align:start position:0% +before + + + align:start position:0% +before +J if I was not using lexographic order + + align:start position:0% +J if I was not using lexographic order + + + align:start position:0% +J if I was not using lexographic order +it might have been reasonable to write + + align:start position:0% +it might have been reasonable to write + + + align:start position:0% +it might have been reasonable to write +for instance when I was expending I to + + align:start position:0% +for instance when I was expending I to + + + align:start position:0% +for instance when I was expending I to +write J before G because J was higher up + + align:start position:0% +write J before G because J was higher up + + + align:start position:0% +write J before G because J was higher up +on the tree or something like that but + + align:start position:0% +on the tree or something like that but + + + align:start position:0% +on the tree or something like that but +the only way it came into play is that I + + align:start position:0% +the only way it came into play is that I + + + align:start position:0% +the only way it came into play is that I +wrote them left to right in alphabetic + + align:start position:0% +wrote them left to right in alphabetic + + + align:start position:0% +wrote them left to right in alphabetic +order every time and I wrote + + align:start position:0% +order every time and I wrote + + + align:start position:0% +order every time and I wrote +ABC another question + + align:start position:0% + + + + align:start position:0% + +I we have visited F again and we would + + align:start position:0% +I we have visited F again and we would + + + align:start position:0% +I we have visited F again and we would +have visited F again that's correct the + + align:start position:0% +have visited F again that's correct the + + + align:start position:0% +have visited F again that's correct the +question is f is listed twice so if we + + align:start position:0% +question is f is listed twice so if we + + + align:start position:0% +question is f is listed twice so if we +hadn't reached the goal node let's say + + align:start position:0% +hadn't reached the goal node let's say + + + align:start position:0% +hadn't reached the goal node let's say +that down there after I is z and after Z + + align:start position:0% +that down there after I is z and after Z + + + align:start position:0% +that down there after I is z and after Z +is the goal node then would we have + + align:start position:0% +is the goal node then would we have + + + align:start position:0% +is the goal node then would we have +visited F again the answer is yes as I + + align:start position:0% +visited F again the answer is yes as I + + + align:start position:0% +visited F again the answer is yes as I +said this is the approach that throws + + align:start position:0% +said this is the approach that throws + + + align:start position:0% +said this is the approach that throws +your troops every possible way so + + align:start position:0% +your troops every possible way so + + + align:start position:0% +your troops every possible way so +there's Storm Troopers going from E to F + + align:start position:0% +there's Storm Troopers going from E to F + + + align:start position:0% +there's Storm Troopers going from E to F +and there's Storm Troopers going from H + + align:start position:0% +and there's Storm Troopers going from H + + + align:start position:0% +and there's Storm Troopers going from H +to F and they're going everywhere now + + align:start position:0% +to F and they're going everywhere now + + + align:start position:0% +to F and they're going everywhere now +there is a way to cut down on this you + + align:start position:0% +there is a way to cut down on this you + + + align:start position:0% +there is a way to cut down on this you +could do breath first search with an + + align:start position:0% +could do breath first search with an + + + align:start position:0% +could do breath first search with an +extended list + + align:start position:0% +extended list + + + align:start position:0% +extended list +if you did do Brett first search with an + + align:start position:0% +if you did do Brett first search with an + + + align:start position:0% +if you did do Brett first search with an +extended list that would be sort of + + align:start position:0% +extended list that would be sort of + + + align:start position:0% +extended list that would be sort of +equivalent to after as soon as you + + align:start position:0% +equivalent to after as soon as you + + + align:start position:0% +equivalent to after as soon as you +expand one node you know as soon as + + align:start position:0% +expand one node you know as soon as + + + align:start position:0% +expand one node you know as soon as +storm you send Storm Troopers out of I + + align:start position:0% +storm you send Storm Troopers out of I + + + align:start position:0% +storm you send Storm Troopers out of I +to look at g& J one of them stays at I + + align:start position:0% +to look at g& J one of them stays at I + + + align:start position:0% +to look at g& J one of them stays at I +and if any other Storm Troopers come to + + align:start position:0% +and if any other Storm Troopers come to + + + align:start position:0% +and if any other Storm Troopers come to +I and they're like oh we want to see + + align:start position:0% +I and they're like oh we want to see + + + align:start position:0% +I and they're like oh we want to see +what's past ey he's like no no no we've + + align:start position:0% +what's past ey he's like no no no we've + + + align:start position:0% +what's past ey he's like no no no we've +already sent troops past ey we've got + + align:start position:0% +already sent troops past ey we've got + + + align:start position:0% +already sent troops past ey we've got +this go back home you're it's it's it's + + align:start position:0% +this go back home you're it's it's it's + + + align:start position:0% +this go back home you're it's it's it's +okay there are no Rebels here but it + + align:start position:0% +okay there are no Rebels here but it + + + align:start position:0% +okay there are no Rebels here but it +might be Han Solo dressed up as a + + align:start position:0% +might be Han Solo dressed up as a + + + align:start position:0% +might be Han Solo dressed up as a +stormtrooper as we'll see in the next + + align:start position:0% +stormtrooper as we'll see in the next + + + align:start position:0% +stormtrooper as we'll see in the next +problem um where our extended list + + align:start position:0% +problem um where our extended list + + + align:start position:0% +problem um where our extended list +screws us up + + align:start position:0% +screws us up + + + align:start position:0% +screws us up +um but for this problem um you see what + + align:start position:0% +um but for this problem um you see what + + + align:start position:0% +um but for this problem um you see what +I mean with an extended list we could + + align:start position:0% +I mean with an extended list we could + + + align:start position:0% +I mean with an extended list we could +avoid this because the extended list + + align:start position:0% +avoid this because the extended list + + + align:start position:0% +avoid this because the extended list +basically says once I've expanded and + + align:start position:0% +basically says once I've expanded and + + + align:start position:0% +basically says once I've expanded and +search past here don't do it again but + + align:start position:0% +search past here don't do it again but + + + align:start position:0% +search past here don't do it again but +if you don't have one yeah you'll do F + + align:start position:0% +if you don't have one yeah you'll do F + + + align:start position:0% +if you don't have one yeah you'll do F +twice in fact didn't we do something + + align:start position:0% +twice in fact didn't we do something + + + align:start position:0% +twice in fact didn't we do something +twice here oh it turns out we didn't but + + align:start position:0% +twice here oh it turns out we didn't but + + + align:start position:0% +twice here oh it turns out we didn't but +we we easily could have we almost did E + + align:start position:0% +we we easily could have we almost did E + + + align:start position:0% +we we easily could have we almost did E +twice we almost did uh we almost did F + + align:start position:0% +twice we almost did uh we almost did F + + + align:start position:0% +twice we almost did uh we almost did F +twice it turns out we didn't but we + + align:start position:0% +twice it turns out we didn't but we + + + align:start position:0% +twice it turns out we didn't but we +could have another question we assume + + align:start position:0% +could have another question we assume + + + align:start position:0% +could have another question we assume +that for the impementation of the that + + align:start position:0% +that for the impementation of the that + + + align:start position:0% +that for the impementation of the that +when you + + align:start position:0% +when you + + + align:start position:0% +when you +expand G and + + align:start position:0% + + + + align:start position:0% + +addan J so stop that's a very good + + align:start position:0% +addan J so stop that's a very good + + + align:start position:0% +addan J so stop that's a very good +question that provokes a minor change + + align:start position:0% +question that provokes a minor change + + + align:start position:0% +question that provokes a minor change +the question is when you expand + + align:start position:0% +the question is when you expand + + + align:start position:0% +the question is when you expand +sbhi is sbig added before sbhi J because + + align:start position:0% +sbhi is sbig added before sbhi J because + + + align:start position:0% +sbhi is sbig added before sbhi J because +of lexographic ordering or they both add + + align:start position:0% +of lexographic ordering or they both add + + + align:start position:0% +of lexographic ordering or they both add +at the same time the answer is + + align:start position:0% +at the same time the answer is + + + align:start position:0% +at the same time the answer is +simultaneous when you do the expansion + + align:start position:0% +simultaneous when you do the expansion + + + align:start position:0% +simultaneous when you do the expansion +you instantly receive a say a list maybe + + align:start position:0% +you instantly receive a say a list maybe + + + align:start position:0% +you instantly receive a say a list maybe +or whatever data structure you like + + align:start position:0% +or whatever data structure you like + + + align:start position:0% +or whatever data structure you like +containing all of the children and they + + align:start position:0% +containing all of the children and they + + + align:start position:0% +containing all of the children and they +all go get appended to the Queue at once + + align:start position:0% +all go get appended to the Queue at once + + + align:start position:0% +all go get appended to the Queue at once +in + + align:start position:0% +in + + + align:start position:0% +in +order so um you will receive all of them + + align:start position:0% +order so um you will receive all of them + + + align:start position:0% +order so um you will receive all of them +like I suppose you could create some + + align:start position:0% +like I suppose you could create some + + + align:start position:0% +like I suppose you could create some +kind of search problem where you have + + align:start position:0% +kind of search problem where you have + + + align:start position:0% +kind of search problem where you have +like an adversary node like a wus or + + align:start position:0% +like an adversary node like a wus or + + + align:start position:0% +like an adversary node like a wus or +you're hunting a wus and if you you + + align:start position:0% +you're hunting a wus and if you you + + + align:start position:0% +you're hunting a wus and if you you +don't want to add the exact wus to your + + align:start position:0% +don't want to add the exact wus to your + + + align:start position:0% +don't want to add the exact wus to your +search tree or you lose you only want to + + align:start position:0% +search tree or you lose you only want to + + + align:start position:0% +search tree or you lose you only want to +add the one next to the wus I don't know + + align:start position:0% +add the one next to the wus I don't know + + + align:start position:0% +add the one next to the wus I don't know +I'm making this up and unfortunately you + + align:start position:0% +I'm making this up and unfortunately you + + + align:start position:0% +I'm making this up and unfortunately you +would have to add all the you have to + + align:start position:0% +would have to add all the you have to + + + align:start position:0% +would have to add all the you have to +add all the children at once you uh our + + align:start position:0% +add all the children at once you uh our + + + align:start position:0% +add all the children at once you uh our +current algorithm does not add uh one at + + align:start position:0% +current algorithm does not add uh one at + + + align:start position:0% +current algorithm does not add uh one at +a + + align:start position:0% +a + + + align:start position:0% +a +time all right so we've done a breath + + align:start position:0% +time all right so we've done a breath + + + align:start position:0% +time all right so we've done a breath +for a search great now we're going to do + + align:start position:0% +for a search great now we're going to do + + + align:start position:0% +for a search great now we're going to do +some optimal + + align:start position:0% +some optimal + + + align:start position:0% +some optimal +search that is going to require me to + + align:start position:0% +search that is going to require me to + + + align:start position:0% +search that is going to require me to +draw a slightly different graph I will + + align:start position:0% +draw a slightly different graph I will + + + align:start position:0% +draw a slightly different graph I will +draw it on what is left of the bottom + + align:start position:0% +draw it on what is left of the bottom + + + align:start position:0% +draw it on what is left of the bottom +here and then we'll solve it on on what + + align:start position:0% +here and then we'll solve it on on what + + + align:start position:0% +here and then we'll solve it on on what +is left of the bottom here so all right + + align:start position:0% +is left of the bottom here so all right + + + align:start position:0% +is left of the bottom here so all right +Mark has his new stronghold and he wants + + align:start position:0% +Mark has his new stronghold and he wants + + + align:start position:0% +Mark has his new stronghold and he wants +to invade parallel + + align:start position:0% +to invade parallel + + + align:start position:0% +to invade parallel +universes now he's going to he's + + align:start position:0% +universes now he's going to he's + + + align:start position:0% +universes now he's going to he's +programmed his evil supercomputer to + + align:start position:0% +programmed his evil supercomputer to + + + align:start position:0% +programmed his evil supercomputer to +find the shortest path of jumps from his + + align:start position:0% +find the shortest path of jumps from his + + + align:start position:0% +find the shortest path of jumps from his +starting Universe to the goal Universe G + + align:start position:0% +starting Universe to the goal Universe G + + + align:start position:0% +starting Universe to the goal Universe G +he's + + align:start position:0% +he's + + + align:start position:0% +he's +also it takes a certain amount of energy + + align:start position:0% +also it takes a certain amount of energy + + + align:start position:0% +also it takes a certain amount of energy +to move from Universe to Universe based + + align:start position:0% +to move from Universe to Universe based + + + align:start position:0% +to move from Universe to Universe based +on the differing factors between those + + align:start position:0% +on the differing factors between those + + + align:start position:0% +on the differing factors between those +universes like maybe in one + + align:start position:0% +universes like maybe in one + + + align:start position:0% +universes like maybe in one +Universe a butterfly didn't flap its + + align:start position:0% +Universe a butterfly didn't flap its + + + align:start position:0% +Universe a butterfly didn't flap its +wings in China whereas in the other + + align:start position:0% +wings in China whereas in the other + + + align:start position:0% +wings in China whereas in the other +Universe there's a sentient reptiles + + align:start position:0% +Universe there's a sentient reptiles + + + align:start position:0% +Universe there's a sentient reptiles +rule the Earth um and so he has Mark + + align:start position:0% +rule the Earth um and so he has Mark + + + align:start position:0% +rule the Earth um and so he has Mark +supercomputer has tried to create a + + align:start position:0% +supercomputer has tried to create a + + + align:start position:0% +supercomputer has tried to create a +heris value that determines how + + align:start position:0% +heris value that determines how + + + align:start position:0% +heris value that determines how +different the universes are to guess + + align:start position:0% +different the universes are to guess + + + align:start position:0% +different the universes are to guess +sort of how much energy it's going to + + align:start position:0% +sort of how much energy it's going to + + + align:start position:0% +sort of how much energy it's going to +take to get from his start Universe s to + + align:start position:0% +take to get from his start Universe s to + + + align:start position:0% +take to get from his start Universe s to +his goal Universe G given that he's at a + + align:start position:0% +his goal Universe G given that he's at a + + + align:start position:0% +his goal Universe G given that he's at a +he's he currently his armies are at a + + align:start position:0% +he's he currently his armies are at a + + + align:start position:0% +he's he currently his armies are at a +particular Universe in other words okay + + align:start position:0% +particular Universe in other words okay + + + align:start position:0% +particular Universe in other words okay +it's not a ukian search but damn it + + align:start position:0% +it's not a ukian search but damn it + + + align:start position:0% +it's not a ukian search but damn it +we're going to have a heris distance to + + align:start position:0% +we're going to have a heris distance to + + + align:start position:0% +we're going to have a heris distance to +the goal and we're going to have a graph + + align:start position:0% +the goal and we're going to have a graph + + + align:start position:0% +the goal and we're going to have a graph +with distances so let's see what it + + align:start position:0% +with distances so let's see what it + + + align:start position:0% +with distances so let's see what it +looks + + align:start position:0% +looks + + + align:start position:0% +looks +like all right + + align:start position:0% + + + + align:start position:0% + +and down here is + + align:start position:0% +and down here is + + + align:start position:0% +and down here is +G so this otherwise I'm assuming heart + + align:start position:0% +G so this otherwise I'm assuming heart + + + align:start position:0% +G so this otherwise I'm assuming heart +shape hides an evil Invasion Force so + + align:start position:0% +shape hides an evil Invasion Force so + + + align:start position:0% +shape hides an evil Invasion Force so +um let's see the distance here is 100 + + align:start position:0% +um let's see the distance here is 100 + + + align:start position:0% +um let's see the distance here is 100 +the distance here is three four the + + align:start position:0% +the distance here is three four the + + + align:start position:0% +the distance here is three four the +distance here is four distance here is + + align:start position:0% +distance here is four distance here is + + + align:start position:0% +distance here is four distance here is + + align:start position:0% + + + align:start position:0% +50 14 + + align:start position:0% +50 14 + + + align:start position:0% +50 14 +4 16 + + align:start position:0% +4 16 + + + align:start position:0% +4 16 +16 oh sorry these are + + align:start position:0% +16 oh sorry these are + + + align:start position:0% +16 oh sorry these are +connected + + align:start position:0% +connected + + + align:start position:0% +connected +30 and + + align:start position:0% +30 and + + + align:start position:0% +30 and +10 theistic values are zero at the start + + align:start position:0% +10 theistic values are zero at the start + + + align:start position:0% +10 theistic values are zero at the start +node 50 at + + align:start position:0% +node 50 at + + + align:start position:0% +node 50 at +B 60 at + + align:start position:0% +B 60 at + + + align:start position:0% +B 60 at +a 55 at + + align:start position:0% +a 55 at + + + align:start position:0% +a 55 at +C 50 at d + + align:start position:0% + + + + align:start position:0% + +56 at + + align:start position:0% +56 at + + + align:start position:0% +56 at +e 50 at + + align:start position:0% + + + + align:start position:0% + +F zero at G because it's the goal + + align:start position:0% +F zero at G because it's the goal + + + align:start position:0% +F zero at G because it's the goal +mode 39 at H I'll draw the little H + + align:start position:0% + + + + align:start position:0% + +smaller and zero at + + align:start position:0% +smaller and zero at + + + align:start position:0% +smaller and zero at +I well after all I goes right to G it + + align:start position:0% +I well after all I goes right to G it + + + align:start position:0% +I well after all I goes right to G it +can be zero it'll be great Okay so + + align:start position:0% +can be zero it'll be great Okay so + + + align:start position:0% +can be zero it'll be great Okay so +now this time Mark is trying to conserve + + align:start position:0% +now this time Mark is trying to conserve + + + align:start position:0% +now this time Mark is trying to conserve +the energy of his parallel universe + + align:start position:0% +the energy of his parallel universe + + + align:start position:0% +the energy of his parallel universe +jumper that understandably takes a lot + + align:start position:0% +jumper that understandably takes a lot + + + align:start position:0% +jumper that understandably takes a lot +of energy so he needs to find he needs + + align:start position:0% +of energy so he needs to find he needs + + + align:start position:0% +of energy so he needs to find he needs +to program in the shortest number of + + align:start position:0% +to program in the shortest number of + + + align:start position:0% +to program in the shortest number of +universe jumps that will get him to the + + align:start position:0% +universe jumps that will get him to the + + + align:start position:0% +universe jumps that will get him to the +goal he he's not interest and he doesn't + + align:start position:0% +goal he he's not interest and he doesn't + + + align:start position:0% +goal he he's not interest and he doesn't +mean the least number of jumps he means + + align:start position:0% +mean the least number of jumps he means + + + align:start position:0% +mean the least number of jumps he means +the least amount of energy on these + + align:start position:0% +the least amount of energy on these + + + align:start position:0% +the least amount of energy on these +edges he's not interested in conquering + + align:start position:0% +edges he's not interested in conquering + + + align:start position:0% +edges he's not interested in conquering +in getting to this new world and not + + align:start position:0% +in getting to this new world and not + + + align:start position:0% +in getting to this new world and not +having enough energy left to blast the + + align:start position:0% +having enough energy left to blast the + + + align:start position:0% +having enough energy left to blast the +crap out of it so we need to find the + + align:start position:0% +crap out of it so we need to find the + + + align:start position:0% +crap out of it so we need to find the +shortest path so first Mark programs a + + align:start position:0% +shortest path so first Mark programs a + + + align:start position:0% +shortest path so first Mark programs a +simple br in Bound search he adds in an + + align:start position:0% +simple br in Bound search he adds in an + + + align:start position:0% +simple br in Bound search he adds in an +extended list to his branch and bound + + align:start position:0% +extended list to his branch and bound + + + align:start position:0% +extended list to his branch and bound +just to make it a little bit faster as + + align:start position:0% +just to make it a little bit faster as + + + align:start position:0% +just to make it a little bit faster as +usual he breaks ties of equal length in + + align:start position:0% +usual he breaks ties of equal length in + + + align:start position:0% +usual he breaks ties of equal length in +lexographic order so let's list the + + align:start position:0% +lexographic order so let's list the + + + align:start position:0% +lexographic order so let's list the +nodes that Mark's computer adds to the + + align:start position:0% +nodes that Mark's computer adds to the + + + align:start position:0% +nodes that Mark's computer adds to the +extended list in + + align:start position:0% +extended list in + + + align:start position:0% +extended list in +order distances are shown next to the + + align:start position:0% +order distances are shown next to the + + + align:start position:0% +order distances are shown next to the +edges ignore the number in parentheses + + align:start position:0% +edges ignore the number in parentheses + + + align:start position:0% +edges ignore the number in parentheses +for now they are heris and we're not + + align:start position:0% +for now they are heris and we're not + + + align:start position:0% +for now they are heris and we're not +using them so that brings me to another + + align:start position:0% +using them so that brings me to another + + + align:start position:0% +using them so that brings me to another +point that I'd like to drive home before + + align:start position:0% +point that I'd like to drive home before + + + align:start position:0% +point that I'd like to drive home before +we go for the home stretch and solve + + align:start position:0% +we go for the home stretch and solve + + + align:start position:0% +we go for the home stretch and solve +these problems + + align:start position:0% +these problems + + + align:start position:0% +these problems +what the heck is the difference between + + align:start position:0% +what the heck is the difference between + + + align:start position:0% +what the heck is the difference between +branch and bound and a star okay I like + + align:start position:0% +branch and bound and a star okay I like + + + align:start position:0% +branch and bound and a star okay I like +to liken it to the following I probably + + align:start position:0% +to liken it to the following I probably + + + align:start position:0% +to liken it to the following I probably +should have I'll make this a SilverStar + + align:start position:0% + + + + align:start position:0% + +idea okay the SilverStar idea is pizza + + align:start position:0% +idea okay the SilverStar idea is pizza + + + align:start position:0% +idea okay the SilverStar idea is pizza +it doesn't really look like pizza but + + align:start position:0% +it doesn't really look like pizza but + + + align:start position:0% +it doesn't really look like pizza but +that's a SilverStar idea Branch inbound + + align:start position:0% +that's a SilverStar idea Branch inbound + + + align:start position:0% +that's a SilverStar idea Branch inbound +is a cheese pizza it's simple if you + + align:start position:0% +is a cheese pizza it's simple if you + + + align:start position:0% +is a cheese pizza it's simple if you +order it for a large group event of + + align:start position:0% +order it for a large group event of + + + align:start position:0% +order it for a large group event of +college students they will eat it and + + align:start position:0% +college students they will eat it and + + + align:start position:0% +college students they will eat it and +think things will be + + align:start position:0% +think things will be + + + align:start position:0% +think things will be +okay now a star search is some kind of + + align:start position:0% +okay now a star search is some kind of + + + align:start position:0% +okay now a star search is some kind of +meat lovers of supreme pizza maybe a + + align:start position:0% +meat lovers of supreme pizza maybe a + + + align:start position:0% +meat lovers of supreme pizza maybe a +meat lovers Pizza it's got all these + + align:start position:0% +meat lovers Pizza it's got all these + + + align:start position:0% +meat lovers Pizza it's got all these +extra toppings a lot of people are + + align:start position:0% +extra toppings a lot of people are + + + align:start position:0% +extra toppings a lot of people are +really going to like it it might be + + align:start position:0% +really going to like it it might be + + + align:start position:0% +really going to like it it might be +better but then you've got a vegetarian + + align:start position:0% +better but then you've got a vegetarian + + + align:start position:0% +better but then you've got a vegetarian +and everything's screwed + + align:start position:0% +and everything's screwed + + + align:start position:0% +and everything's screwed +up so basically branch and a star is + + align:start position:0% +up so basically branch and a star is + + + align:start position:0% +up so basically branch and a star is +just branch and bound with some extra + + align:start position:0% +just branch and bound with some extra + + + align:start position:0% +just branch and bound with some extra +toppings added on in this case one of + + align:start position:0% +toppings added on in this case one of + + + align:start position:0% +toppings added on in this case one of +the Toppings is an extended list uh + + align:start position:0% +the Toppings is an extended list uh + + + align:start position:0% +the Toppings is an extended list uh +extended list which uh we'll see keeps + + align:start position:0% +extended list which uh we'll see keeps + + + align:start position:0% +extended list which uh we'll see keeps +track of where we where we've passed + + align:start position:0% +track of where we where we've passed + + + align:start position:0% +track of where we where we've passed +through and already expended out and it + + align:start position:0% +through and already expended out and it + + + align:start position:0% +through and already expended out and it +never goes back the other topping that + + align:start position:0% +never goes back the other topping that + + + align:start position:0% +never goes back the other topping that +we were going to add is a heuristic + + align:start position:0% +we were going to add is a heuristic + + + align:start position:0% +we were going to add is a heuristic +heuristic tells us about how far we + + align:start position:0% +heuristic tells us about how far we + + + align:start position:0% +heuristic tells us about how far we +think we have left until we're at the + + align:start position:0% +think we have left until we're at the + + + align:start position:0% +think we have left until we're at the +end so we don't go through really short + + align:start position:0% +end so we don't go through really short + + + align:start position:0% +end so we don't go through really short +paths that go completely in the wrong + + align:start position:0% +paths that go completely in the wrong + + + align:start position:0% +paths that go completely in the wrong +direction all right between the two of + + align:start position:0% +direction all right between the two of + + + align:start position:0% +direction all right between the two of +those we get our supreme pizza but + + align:start position:0% +those we get our supreme pizza but + + + align:start position:0% +those we get our supreme pizza but +sometimes as we'll see they they sort of + + align:start position:0% +sometimes as we'll see they they sort of + + + align:start position:0% +sometimes as we'll see they they sort of +mess each other up so you know one of + + align:start position:0% +mess each other up so you know one of + + + align:start position:0% +mess each other up so you know one of +the topics just doesn't go well with the + + align:start position:0% +the topics just doesn't go well with the + + + align:start position:0% +the topics just doesn't go well with the +other one maybe a lot someone does like + + align:start position:0% +other one maybe a lot someone does like + + + align:start position:0% +other one maybe a lot someone does like +Hawaiian they think that the the ham + + align:start position:0% +Hawaiian they think that the the ham + + + align:start position:0% +Hawaiian they think that the the ham +doesn't go well with the pineapple + + align:start position:0% +doesn't go well with the pineapple + + + align:start position:0% +doesn't go well with the pineapple +anyway so let's do a branch inbound that + + align:start position:0% +anyway so let's do a branch inbound that + + + align:start position:0% +anyway so let's do a branch inbound that +just has an extended list maybe we've + + align:start position:0% +just has an extended list maybe we've + + + align:start position:0% +just has an extended list maybe we've +got some green peppers on this pizza + + align:start position:0% +got some green peppers on this pizza + + + align:start position:0% +got some green peppers on this pizza +this is going to be + + align:start position:0% +this is going to be + + + align:start position:0% +this is going to be +safe um all right so we're going to list + + align:start position:0% +safe um all right so we're going to list + + + align:start position:0% +safe um all right so we're going to list +the noesy as the extended list and the + + align:start position:0% +the noesy as the extended list and the + + + align:start position:0% +the noesy as the extended list and the +way we're going to do that is well you + + align:start position:0% +way we're going to do that is well you + + + align:start position:0% +way we're going to do that is well you +guys said you like gold tree more than Q + + align:start position:0% +guys said you like gold tree more than Q + + + align:start position:0% +guys said you like gold tree more than Q +so let's do it with a gold tree so we've + + align:start position:0% +so let's do it with a gold tree so we've + + + align:start position:0% +so let's do it with a gold tree so we've +got s and as we already know s goes + + align:start position:0% +got s and as we already know s goes + + + align:start position:0% +got s and as we already know s goes +well s is the only + + align:start position:0% +well s is the only + + + align:start position:0% +well s is the only +path our current length at s is zero + + align:start position:0% +path our current length at s is zero + + + align:start position:0% +path our current length at s is zero +that's the lowest of all of our lengths + + align:start position:0% +that's the lowest of all of our lengths + + + align:start position:0% +that's the lowest of all of our lengths +on the tree because it's the only length + + align:start position:0% +on the tree because it's the only length + + + align:start position:0% +on the tree because it's the only length +so we go to a b and + + align:start position:0% +so we go to a b and + + + align:start position:0% +so we go to a b and +c okay so what is everyone um it may be + + align:start position:0% +c okay so what is everyone um it may be + + + align:start position:0% +c okay so what is everyone um it may be +hard to see so the length of sa is + + align:start position:0% +hard to see so the length of sa is + + + align:start position:0% +hard to see so the length of sa is +100 the length of SB + + align:start position:0% + + + + align:start position:0% + +is + + align:start position:0% +is + + + align:start position:0% +is +H oh you're right it's a different tree + + align:start position:0% +H oh you're right it's a different tree + + + align:start position:0% +H oh you're right it's a different tree +I was doing ab and C from the other tree + + align:start position:0% +I was doing ab and C from the other tree + + + align:start position:0% +I was doing ab and C from the other tree +thank you friends for correcting my + + align:start position:0% + + + + align:start position:0% + +foolishness the length of SB is three it + + align:start position:0% +foolishness the length of SB is three it + + + align:start position:0% +foolishness the length of SB is three it +is a different tree I was trying to save + + align:start position:0% +is a different tree I was trying to save + + + align:start position:0% +is a different tree I was trying to save +work that wound up creating more because + + align:start position:0% +work that wound up creating more because + + + align:start position:0% +work that wound up creating more because +someone's going to be confused by this + + align:start position:0% +someone's going to be confused by this + + + align:start position:0% +someone's going to be confused by this +so the length of a e and f are 1034 and + + align:start position:0% +so the length of a e and f are 1034 and + + + align:start position:0% +so the length of a e and f are 1034 and +14 which which one do we choose lexor + + align:start position:0% +14 which which one do we choose lexor + + + align:start position:0% +14 which which one do we choose lexor +graphically it's a we choose that one + + align:start position:0% +graphically it's a we choose that one + + + align:start position:0% +graphically it's a we choose that one +right f is going to be 14 that's a one + + align:start position:0% +right f is going to be 14 that's a one + + + align:start position:0% +right f is going to be 14 that's a one +sorry we oh it's + + align:start position:0% +sorry we oh it's + + + align:start position:0% +sorry we oh it's +four I wrote this problem I should know + + align:start position:0% +four I wrote this problem I should know + + + align:start position:0% +four I wrote this problem I should know +it you're right f f is four my apologies + + align:start position:0% +it you're right f f is four my apologies + + + align:start position:0% +it you're right f f is four my apologies +is once more that's what I get all right + + align:start position:0% +is once more that's what I get all right + + + align:start position:0% +is once more that's what I get all right +I'm going to send over here from now on + + align:start position:0% +I'm going to send over here from now on + + + align:start position:0% +I'm going to send over here from now on +when I write over + + align:start position:0% +when I write over + + + align:start position:0% +when I write over +there okay um so which one of these are + + align:start position:0% +there okay um so which one of these are + + + align:start position:0% +there okay um so which one of these are +we going to choose even with the four + + align:start position:0% +we going to choose even with the four + + + align:start position:0% +we going to choose even with the four +we're going to choose B that's right Le + + align:start position:0% +we're going to choose B that's right Le + + + align:start position:0% +we're going to choose B that's right Le +the graphic be damned it's only for ties + + align:start position:0% +the graphic be damned it's only for ties + + + align:start position:0% +the graphic be damned it's only for ties +we want the shortest path our special + + align:start position:0% +we want the shortest path our special + + + align:start position:0% +we want the shortest path our special +thing with brench and bound is we take + + align:start position:0% +thing with brench and bound is we take + + + align:start position:0% +thing with brench and bound is we take +the currently shortest path whatever it + + align:start position:0% +the currently shortest path whatever it + + + align:start position:0% +the currently shortest path whatever it +is great so we spend B fortunately and + + align:start position:0% +is great so we spend B fortunately and + + + align:start position:0% +is great so we spend B fortunately and +I'm pretty sure I've got this correct + + align:start position:0% +I'm pretty sure I've got this correct + + + align:start position:0% +I'm pretty sure I've got this correct +this time oh wait I've got an even + + align:start position:0% +this time oh wait I've got an even + + + align:start position:0% +this time oh wait I've got an even +better idea I'll just take this little + + align:start position:0% +better idea I'll just take this little + + + align:start position:0% +better idea I'll just take this little +hand sheet with me and then I don't have + + align:start position:0% +hand sheet with me and then I don't have + + + align:start position:0% +hand sheet with me and then I don't have +to look at that at all okay so once we + + align:start position:0% +to look at that at all okay so once we + + + align:start position:0% +to look at that at all okay so once we +expand b b goes to + + align:start position:0% +expand b b goes to + + + align:start position:0% +expand b b goes to +D our path length from B to D is four so + + align:start position:0% +D our path length from B to D is four so + + + align:start position:0% +D our path length from B to D is four so +what will we write next to Little D here + + align:start position:0% +what will we write next to Little D here + + + align:start position:0% +what will we write next to Little D here +seven that's right we add them all + + align:start position:0% +seven that's right we add them all + + + align:start position:0% +seven that's right we add them all +together I'm going to ask you guys again + + align:start position:0% +together I'm going to ask you guys again + + + align:start position:0% +together I'm going to ask you guys again +the next time we do this with theistic + + align:start position:0% +the next time we do this with theistic + + + align:start position:0% +the next time we do this with theistic +which is going to be the next part of + + align:start position:0% +which is going to be the next part of + + + align:start position:0% +which is going to be the next part of +the problem and someone's going to give + + align:start position:0% +the problem and someone's going to give + + + align:start position:0% +the problem and someone's going to give +me the wrong answer next time so stay + + align:start position:0% +me the wrong answer next time so stay + + + align:start position:0% +me the wrong answer next time so stay +tuned for that all right so we've got + + align:start position:0% +tuned for that all right so we've got + + + align:start position:0% +tuned for that all right so we've got +SPD we've got all of these where do we + + align:start position:0% +SPD we've got all of these where do we + + + align:start position:0% +SPD we've got all of these where do we +go next F that's right because currently + + align:start position:0% +go next F that's right because currently + + + align:start position:0% +go next F that's right because currently +four is the shortest because you guys + + align:start position:0% +four is the shortest because you guys + + + align:start position:0% +four is the shortest because you guys +corrected me correctly so SF four is the + + align:start position:0% +corrected me correctly so SF four is the + + + align:start position:0% +corrected me correctly so SF four is the +shortest F only goes to h and what do we + + align:start position:0% +shortest F only goes to h and what do we + + + align:start position:0% +shortest F only goes to h and what do we +write next to the h + + align:start position:0% +write next to the h + + + align:start position:0% +write next to the h +20 that's + + align:start position:0% +20 that's + + + align:start position:0% +20 that's +right 16 + 4 20 all right where's our + + align:start position:0% +right 16 + 4 20 all right where's our + + + align:start position:0% +right 16 + 4 20 all right where's our +current shortest it's the D SBD all + + align:start position:0% +current shortest it's the D SBD all + + + align:start position:0% +current shortest it's the D SBD all +right so SBD D only goes to I and we've + + align:start position:0% +right so SBD D only goes to I and we've + + + align:start position:0% +right so SBD D only goes to I and we've +got a 57 oh I want to get wait a + + align:start position:0% + + + + align:start position:0% + +minute 57 I think wait a minute I want + + align:start position:0% +minute 57 I think wait a minute I want + + + align:start position:0% +minute 57 I think wait a minute I want +to get this problem right so we better + + align:start position:0% +to get this problem right so we better + + + align:start position:0% +to get this problem right so we better +actually write the extended list better + + align:start position:0% +actually write the extended list better + + + align:start position:0% +actually write the extended list better +at we because that's the only thing + + align:start position:0% +at we because that's the only thing + + + align:start position:0% +at we because that's the only thing +they're asking us for so first first we + + align:start position:0% +they're asking us for so first first we + + + align:start position:0% +they're asking us for so first first we +extended s then we extended + + align:start position:0% +extended s then we extended + + + align:start position:0% +extended s then we extended +B then we extended + + align:start position:0% +B then we extended + + + align:start position:0% +B then we extended +F then we extended + + align:start position:0% +F then we extended + + + align:start position:0% +F then we extended +D all right so far so good and I have + + align:start position:0% +D all right so far so good and I have + + + align:start position:0% +D all right so far so good and I have +the answer key so I know we're doing it + + align:start position:0% +the answer key so I know we're doing it + + + align:start position:0% +the answer key so I know we're doing it +right okay what are we doing next e + + align:start position:0% +right okay what are we doing next e + + + align:start position:0% +right okay what are we doing next e +that's right so we extend e e goes to + + align:start position:0% +that's right so we extend e e goes to + + + align:start position:0% +that's right so we extend e e goes to +h and when e goes to eight we've got a + + align:start position:0% +h and when e goes to eight we've got a + + + align:start position:0% +h and when e goes to eight we've got a +length of 30 all right who's our winner + + align:start position:0% +length of 30 all right who's our winner + + + align:start position:0% +length of 30 all right who's our winner +now which H sfh that's right sfh is + + align:start position:0% +now which H sfh that's right sfh is + + + align:start position:0% +now which H sfh that's right sfh is +length 20 oh yeah of course I should + + align:start position:0% +length 20 oh yeah of course I should + + + align:start position:0% +length 20 oh yeah of course I should +write an e in here I always forget to do + + align:start position:0% +write an e in here I always forget to do + + + align:start position:0% +write an e in here I always forget to do +that sfh is length 20 so we'll extend H + + align:start position:0% +that sfh is length 20 so we'll extend H + + + align:start position:0% +that sfh is length 20 so we'll extend H +and I'm going to write it here + + align:start position:0% +and I'm going to write it here + + + align:start position:0% +and I'm going to write it here +preemptively all right when we extend H + + align:start position:0% +preemptively all right when we extend H + + + align:start position:0% +preemptively all right when we extend H +over here H only goes to I with length + + align:start position:0% +over here H only goes to I with length + + + align:start position:0% +over here H only goes to I with length +50 great what's the next + + align:start position:0% +50 great what's the next + + + align:start position:0% +50 great what's the next +shortest the next shortest is the other + + align:start position:0% +shortest the next shortest is the other + + + align:start position:0% +shortest the next shortest is the other +H however will we expand it you guess + + align:start position:0% +H however will we expand it you guess + + + align:start position:0% +H however will we expand it you guess +that because I asked that question in + + align:start position:0% +that because I asked that question in + + + align:start position:0% +that because I asked that question in +that way you knew the answer was no why + + align:start position:0% +that way you knew the answer was no why + + + align:start position:0% +that way you knew the answer was no why +don't we expand + + align:start position:0% +don't we expand + + + align:start position:0% +don't we expand +it it's already on the extended list + + align:start position:0% +it it's already on the extended list + + + align:start position:0% +it it's already on the extended list +that's right so since it's already on + + align:start position:0% +that's right so since it's already on + + + align:start position:0% +that's right so since it's already on +the expended extended list this one dies + + align:start position:0% +the expended extended list this one dies + + + align:start position:0% +the expended extended list this one dies +a horrible death I like writing an X + + align:start position:0% +a horrible death I like writing an X + + + align:start position:0% +a horrible death I like writing an X +through it instead of writing a swizzle + + align:start position:0% +through it instead of writing a swizzle + + + align:start position:0% +through it instead of writing a swizzle +at the bottom you can do whatever you + + align:start position:0% +at the bottom you can do whatever you + + + align:start position:0% +at the bottom you can do whatever you +want all right it's gone it's not a + + align:start position:0% +want all right it's gone it's not a + + + align:start position:0% +want all right it's gone it's not a +choice what's the next best + + align:start position:0% +choice what's the next best + + + align:start position:0% +choice what's the next best +one sfhi that's right Ro goes to G and + + align:start position:0% +one sfhi that's right Ro goes to G and + + + align:start position:0% +one sfhi that's right Ro goes to G and +the length is 60 and we've extended I + + align:start position:0% +the length is 60 and we've extended I + + + align:start position:0% +the length is 60 and we've extended I +all right + + align:start position:0% +all right + + + align:start position:0% +all right +so question is are we + + align:start position:0% + + + + align:start position:0% + +done the people who say no I like you + + align:start position:0% +done the people who say no I like you + + + align:start position:0% +done the people who say no I like you +you're smart you realize that just + + align:start position:0% +you're smart you realize that just + + + align:start position:0% +you're smart you realize that just +because the G is on there that we can't + + align:start position:0% +because the G is on there that we can't + + + align:start position:0% +because the G is on there that we can't +end how are the people who said yes + + align:start position:0% +end how are the people who said yes + + + align:start position:0% +end how are the people who said yes +you're + + align:start position:0% +you're + + + align:start position:0% +you're +either oblivious or really really smart + + align:start position:0% +either oblivious or really really smart + + + align:start position:0% +either oblivious or really really smart +and I'm going to choose to assume you're + + align:start position:0% +and I'm going to choose to assume you're + + + align:start position:0% +and I'm going to choose to assume you're +all really really smart because the + + align:start position:0% +all really really smart because the + + + align:start position:0% +all really really smart because the +really really smart people said okay yes + + align:start position:0% +really really smart people said okay yes + + + align:start position:0% +really really smart people said okay yes +we're not quite done just because we + + align:start position:0% +we're not quite done just because we + + + align:start position:0% +we're not quite done just because we +added a g we still have to check to make + + align:start position:0% +added a g we still have to check to make + + + align:start position:0% +added a g we still have to check to make +sure there are no length of shorter path + + align:start position:0% +sure there are no length of shorter path + + + align:start position:0% +sure there are no length of shorter path +but look the only one with the shorter + + align:start position:0% +but look the only one with the shorter + + + align:start position:0% +but look the only one with the shorter +path is I which is already on the + + align:start position:0% +path is I which is already on the + + + align:start position:0% +path is I which is already on the +extended list so actually we are done + + align:start position:0% +extended list so actually we are done + + + align:start position:0% +extended list so actually we are done +double Trend we've got it so these are + + align:start position:0% +double Trend we've got it so these are + + + align:start position:0% +double Trend we've got it so these are +the paths we extended in order and our + + align:start position:0% +the paths we extended in order and our + + + align:start position:0% +the paths we extended in order and our +final path is + + align:start position:0% + + + + align:start position:0% + +everyone that's right sfh G I claim that + + align:start position:0% +everyone that's right sfh G I claim that + + + align:start position:0% +everyone that's right sfh G I claim that +is the correct path however Mark is + + align:start position:0% +is the correct path however Mark is + + + align:start position:0% +is the correct path however Mark is +frustrated by branch and bound speed I + + align:start position:0% +frustrated by branch and bound speed I + + + align:start position:0% +frustrated by branch and bound speed I +don't know I wasn't that frustrated + + align:start position:0% +don't know I wasn't that frustrated + + + align:start position:0% +don't know I wasn't that frustrated +seemed pretty good but Mark is + + align:start position:0% +seemed pretty good but Mark is + + + align:start position:0% +seemed pretty good but Mark is +frustrated by brench and brown speed so + + align:start position:0% +frustrated by brench and brown speed so + + + align:start position:0% +frustrated by brench and brown speed so +he reprograms his computer to use a star + + align:start position:0% +he reprograms his computer to use a star + + + align:start position:0% +he reprograms his computer to use a star +Mark counts the number of Subspace + + align:start position:0% +Mark counts the number of Subspace + + + align:start position:0% +Mark counts the number of Subspace +anomalies between each Universe in the + + align:start position:0% +anomalies between each Universe in the + + + align:start position:0% +anomalies between each Universe in the +goal and uses this count as theistic for + + align:start position:0% +goal and uses this count as theistic for + + + align:start position:0% +goal and uses this count as theistic for +a star these numbers are in parentheses + + align:start position:0% +a star these numbers are in parentheses + + + align:start position:0% +a star these numbers are in parentheses +hopefully you can read + + align:start position:0% +hopefully you can read + + + align:start position:0% +hopefully you can read +them yes oh we've got a question right + + align:start position:0% + + + + align:start position:0% + +here ah that a very good question and + + align:start position:0% +here ah that a very good question and + + + align:start position:0% +here ah that a very good question and +the answer is very simple answer you + + align:start position:0% +the answer is very simple answer you + + + align:start position:0% +the answer is very simple answer you +guys tra me no but I should have been + + align:start position:0% +guys tra me no but I should have been + + + align:start position:0% +guys tra me no but I should have been +able to figure it out it does go to CN + + align:start position:0% +able to figure it out it does go to CN + + + align:start position:0% +able to figure it out it does go to CN +D the correct tree which you wouldn't we + + align:start position:0% +D the correct tree which you wouldn't we + + + align:start position:0% +D the correct tree which you wouldn't we +wouldn't have lost points for having the + + align:start position:0% +wouldn't have lost points for having the + + + align:start position:0% +wouldn't have lost points for having the +incorrect tree here we did get the + + align:start position:0% +incorrect tree here we did get the + + + align:start position:0% +incorrect tree here we did get the +correct answer yes the the reason why is + + align:start position:0% +correct answer yes the the reason why is + + + align:start position:0% +correct answer yes the the reason why is +that same reason that very first time I + + align:start position:0% +that same reason that very first time I + + + align:start position:0% +that same reason that very first time I +asked someone something he didn't + + align:start position:0% +asked someone something he didn't + + + align:start position:0% +asked someone something he didn't +remember the C it's easy to forget to go + + align:start position:0% +remember the C it's easy to forget to go + + + align:start position:0% +remember the C it's easy to forget to go +up the tree it does actually have a c + + align:start position:0% +up the tree it does actually have a c + + + align:start position:0% +up the tree it does actually have a c +and d however they are horrendous paths + + align:start position:0% +and d however they are horrendous paths + + + align:start position:0% +and d however they are horrendous paths +they are 100 and 100 + + align:start position:0% +they are 100 and 100 + + + align:start position:0% +they are 100 and 100 +on their on their path length and so it + + align:start position:0% +on their on their path length and so it + + + align:start position:0% +on their on their path length and so it +doesn't matter but you were correct + + align:start position:0% +doesn't matter but you were correct + + + align:start position:0% +doesn't matter but you were correct +official answer we had up there is + + align:start position:0% +official answer we had up there is + + + align:start position:0% +official answer we had up there is +wrong + + align:start position:0% + + + + align:start position:0% + +add good question well the question is + + align:start position:0% +add good question well the question is + + + align:start position:0% +add good question well the question is +would the D get added to the children + + align:start position:0% +would the D get added to the children + + + align:start position:0% +would the D get added to the children +after all it's already in the extended + + align:start position:0% +after all it's already in the extended + + + align:start position:0% +after all it's already in the extended +list the answer is we search for and + + align:start position:0% +list the answer is we search for and + + + align:start position:0% +list the answer is we search for and +remove and kill all of the attempts to + + align:start position:0% +remove and kill all of the attempts to + + + align:start position:0% +remove and kill all of the attempts to +extend something that's already on the + + align:start position:0% +extend something that's already on the + + + align:start position:0% +extend something that's already on the +expended list at the time we try to + + align:start position:0% +expended list at the time we try to + + + align:start position:0% +expended list at the time we try to +expand it the time we try to expand it + + align:start position:0% +expand it the time we try to expand it + + + align:start position:0% +expand it the time we try to expand it +is only when it's on the front of the + + align:start position:0% +is only when it's on the front of the + + + align:start position:0% +is only when it's on the front of the +que because it's the currently shortest + + align:start position:0% +que because it's the currently shortest + + + align:start position:0% +que because it's the currently shortest +path so that means they get added it's + + align:start position:0% +path so that means they get added it's + + + align:start position:0% +path so that means they get added it's +just that when it comes time to expand + + align:start position:0% +just that when it comes time to expand + + + align:start position:0% +just that when it comes time to expand +it it will get crossed off no matter + + align:start position:0% +it it will get crossed off no matter + + + align:start position:0% +it it will get crossed off no matter +what turns out it escaped execution + + align:start position:0% +what turns out it escaped execution + + + align:start position:0% +what turns out it escaped execution +because of the fact that we never + + align:start position:0% +because of the fact that we never + + + align:start position:0% +because of the fact that we never +expanded + + align:start position:0% +expanded + + + align:start position:0% +expanded +it so H should go to e as well is the + + align:start position:0% +it so H should go to e as well is the + + + align:start position:0% +it so H should go to e as well is the +question the answer is yes H should go + + align:start position:0% +question the answer is yes H should go + + + align:start position:0% +question the answer is yes H should go +to e as + + align:start position:0% +to e as + + + align:start position:0% +to e as +well a lot slipped past me this time H + + align:start position:0% +well a lot slipped past me this time H + + + align:start position:0% +well a lot slipped past me this time H +should go to e as well with a length of + + align:start position:0% +should go to e as well with a length of + + + align:start position:0% +should go to e as well with a length of +36 and it dies there + + align:start position:0% + + + + align:start position:0% + +this one will actually be checked so it + + align:start position:0% +this one will actually be checked so it + + + align:start position:0% +this one will actually be checked so it +actually does make a difference if we + + align:start position:0% +actually does make a difference if we + + + align:start position:0% +actually does make a difference if we +ask how many times was a node um + + align:start position:0% +ask how many times was a node um + + + align:start position:0% +ask how many times was a node um +executed due to not going on the extend + + align:start position:0% +executed due to not going on the extend + + + align:start position:0% +executed due to not going on the extend +due to already being on the extended + + align:start position:0% +due to already being on the extended + + + align:start position:0% +due to already being on the extended +list very good very good notice it + + align:start position:0% +list very good very good notice it + + + align:start position:0% +list very good very good notice it +should be on there we'll get it right + + align:start position:0% +should be on there we'll get it right + + + align:start position:0% +should be on there we'll get it right +next + + align:start position:0% +next + + + align:start position:0% +next +time all right everyone so I'm working + + align:start position:0% +time all right everyone so I'm working + + + align:start position:0% +time all right everyone so I'm working +together with you I made the mistake to + + align:start position:0% +together with you I made the mistake to + + + align:start position:0% +together with you I made the mistake to +easy one to make it can it can mess you + + align:start position:0% +easy one to make it can it can mess you + + + align:start position:0% +easy one to make it can it can mess you +up it didn't this time we're going to + + align:start position:0% +up it didn't this time we're going to + + + align:start position:0% +up it didn't this time we're going to +get it up question + + align:start position:0% +get it up question + + + align:start position:0% +get it up question +if G's the + + align:start position:0% +if G's the + + + align:start position:0% +if G's the +goal get G in + + align:start position:0% +goal get G in + + + align:start position:0% +goal get G in +youres and know the number shorter than + + align:start position:0% +youres and know the number shorter than + + + align:start position:0% +youres and know the number shorter than +anything else do you have to actually + + align:start position:0% +anything else do you have to actually + + + align:start position:0% +anything else do you have to actually +extend it g so the question is do you + + align:start position:0% +extend it g so the question is do you + + + align:start position:0% +extend it g so the question is do you +exist do you actually extend G do you + + align:start position:0% +exist do you actually extend G do you + + + align:start position:0% +exist do you actually extend G do you +should should we even put G in the + + align:start position:0% +should should we even put G in the + + + align:start position:0% +should should we even put G in the +extended list the answer is the answer + + align:start position:0% +extended list the answer is the answer + + + align:start position:0% +extended list the answer is the answer +to that question is it is a matter of + + align:start position:0% +to that question is it is a matter of + + + align:start position:0% +to that question is it is a matter of +taste and in the questions where we in + + align:start position:0% +taste and in the questions where we in + + + align:start position:0% +taste and in the questions where we in +my opinion rather foolishly ask how many + + align:start position:0% +my opinion rather foolishly ask how many + + + align:start position:0% +my opinion rather foolishly ask how many +nodes were extended rather than asking + + align:start position:0% +nodes were extended rather than asking + + + align:start position:0% +nodes were extended rather than asking +you to write them out we generally + + align:start position:0% +you to write them out we generally + + + align:start position:0% +you to write them out we generally +accept the answer where you didn't + + align:start position:0% +accept the answer where you didn't + + + align:start position:0% +accept the answer where you didn't +extend or where you did extend G it's an + + align:start position:0% +extend or where you did extend G it's an + + + align:start position:0% +extend or where you did extend G it's an +implementation detail you can either + + align:start position:0% +implementation detail you can either + + + align:start position:0% +implementation detail you can either +have a fail safe that as soon as it sees + + align:start position:0% +have a fail safe that as soon as it sees + + + align:start position:0% +have a fail safe that as soon as it sees +g at the beginning of the list says + + align:start position:0% +g at the beginning of the list says + + + align:start position:0% +g at the beginning of the list says +we're out we're not going to extend + + align:start position:0% +we're out we're not going to extend + + + align:start position:0% +we're out we're not going to extend +we're done we win or fail safe that when + + align:start position:0% +we're done we win or fail safe that when + + + align:start position:0% +we're done we win or fail safe that when +you're about to extend something and you + + align:start position:0% +you're about to extend something and you + + + align:start position:0% +you're about to extend something and you +do go into the extension process and it + + align:start position:0% +do go into the extension process and it + + + align:start position:0% +do go into the extension process and it +sees that it ends in g that it wins so + + align:start position:0% +sees that it ends in g that it wins so + + + align:start position:0% +sees that it ends in g that it wins so +it is a matter of taste if you kind of + + align:start position:0% +it is a matter of taste if you kind of + + + align:start position:0% +it is a matter of taste if you kind of +like to watch your your little guy doing + + align:start position:0% +like to watch your your little guy doing + + + align:start position:0% +like to watch your your little guy doing +the search wi and have an S and a g you + + align:start position:0% +the search wi and have an S and a g you + + + align:start position:0% +the search wi and have an S and a g you +can put it on if you don't you canot put + + align:start position:0% +can put it on if you don't you canot put + + + align:start position:0% +can put it on if you don't you canot put +it on we won't take off points for + + align:start position:0% +it on we won't take off points for + + + align:start position:0% +it on we won't take off points for +whether or not it has a g at the end + + align:start position:0% +whether or not it has a g at the end + + + align:start position:0% +whether or not it has a g at the end +because clearly if you did all the other + + align:start position:0% +because clearly if you did all the other + + + align:start position:0% +because clearly if you did all the other +crazy stuff correct well you could have + + align:start position:0% +crazy stuff correct well you could have + + + align:start position:0% +crazy stuff correct well you could have +written in a g if you wanted to I think + + align:start position:0% +written in a g if you wanted to I think + + + align:start position:0% +written in a g if you wanted to I think +unless like there's someone who + + align:start position:0% +unless like there's someone who + + + align:start position:0% +unless like there's someone who +missolves the problem right at the end + + align:start position:0% +missolves the problem right at the end + + + align:start position:0% +missolves the problem right at the end +is like oh who cares about G oh no it's + + align:start position:0% +is like oh who cares about G oh no it's + + + align:start position:0% +is like oh who cares about G oh no it's +stuck it's a dead end we lose but that + + align:start position:0% +stuck it's a dead end we lose but that + + + align:start position:0% +stuck it's a dead end we lose but that +would be probably pretty rare all right + + align:start position:0% +would be probably pretty rare all right + + + align:start position:0% +would be probably pretty rare all right +so let's solve the um the AAR so I'm not + + align:start position:0% +so let's solve the um the AAR so I'm not + + + align:start position:0% +so let's solve the um the AAR so I'm not +going to make the same mistake twice we + + align:start position:0% +going to make the same mistake twice we + + + align:start position:0% +going to make the same mistake twice we +go from s to a b e + + align:start position:0% + + + + align:start position:0% + +and S by the way had a value of zero all + + align:start position:0% +and S by the way had a value of zero all + + + align:start position:0% +and S by the way had a value of zero all +right what is the value at + + align:start position:0% +right what is the value at + + + align:start position:0% +right what is the value at +a well I think it's + + align:start position:0% +a well I think it's + + + align:start position:0% +a well I think it's +160 the question is how do we calculate + + align:start position:0% +160 the question is how do we calculate + + + align:start position:0% +160 the question is how do we calculate +this well it's the path that we traveled + + align:start position:0% +this well it's the path that we traveled + + + align:start position:0% +this well it's the path that we traveled +so far plus theistic value at the at the + + align:start position:0% +so far plus theistic value at the at the + + + align:start position:0% +so far plus theistic value at the at the +final + + align:start position:0% +final + + + align:start position:0% +final +node by way this is why someone's going + + align:start position:0% +node by way this is why someone's going + + + align:start position:0% +node by way this is why someone's going +to give me the wrong answer at BD but + + align:start position:0% +to give me the wrong answer at BD but + + + align:start position:0% +to give me the wrong answer at BD but +let's see so we have 160 here okay so SB + + align:start position:0% +let's see so we have 160 here okay so SB + + + align:start position:0% +let's see so we have 160 here okay so SB +we've got a uh what is theistic value + + align:start position:0% +we've got a uh what is theistic value + + + align:start position:0% +we've got a uh what is theistic value +here we've got three for the path and 50 + + align:start position:0% +here we've got three for the path and 50 + + + align:start position:0% +here we've got three for the path and 50 +for the theistic so it's + + align:start position:0% +for the theistic so it's + + + align:start position:0% +for the theistic so it's +53 all right SE what have we got here + + align:start position:0% +53 all right SE what have we got here + + + align:start position:0% +53 all right SE what have we got here +we've got 14 for the path 56 for the + + align:start position:0% +we've got 14 for the path 56 for the + + + align:start position:0% +we've got 14 for the path 56 for the +heris so it's + + align:start position:0% +heris so it's + + + align:start position:0% +heris so it's +70 all right SF we've got four for the + + align:start position:0% +70 all right SF we've got four for the + + + align:start position:0% +70 all right SF we've got four for the +path 50 for the herti + + align:start position:0% +path 50 for the herti + + + align:start position:0% +path 50 for the herti +54 okay who's our winner it's B again + + align:start position:0% +54 okay who's our winner it's B again + + + align:start position:0% +54 okay who's our winner it's B again +barely but it is the winner extended + + align:start position:0% +barely but it is the winner extended + + + align:start position:0% +barely but it is the winner extended +list up here SB all right b as we saw + + align:start position:0% +list up here SB all right b as we saw + + + align:start position:0% +list up here SB all right b as we saw +goes only to + + align:start position:0% +goes only to + + + align:start position:0% +goes only to +D what is the what is the value that I + + align:start position:0% +D what is the what is the value that I + + + align:start position:0% +D what is the what is the value that I +should write + + align:start position:0% + + + + align:start position:0% + +here okay I am happy I heard all the + + align:start position:0% +here okay I am happy I heard all the + + + align:start position:0% +here okay I am happy I heard all the +things that I expected to hear I heard + + align:start position:0% +things that I expected to hear I heard + + + align:start position:0% +things that I expected to hear I heard +the correct answer which is uh 57 I also + + align:start position:0% +the correct answer which is uh 57 I also + + + align:start position:0% +the correct answer which is uh 57 I also +heard someone say + + align:start position:0% +heard someone say + + + align:start position:0% +heard someone say +107 so why is it 57 and not + + align:start position:0% +107 so why is it 57 and not + + + align:start position:0% +107 so why is it 57 and not +107 someone does it this way every time + + align:start position:0% +107 someone does it this way every time + + + align:start position:0% +107 someone does it this way every time +do not add up all the heres of law in + + align:start position:0% +do not add up all the heres of law in + + + align:start position:0% +do not add up all the heres of law in +the way I'll try to explain to why you + + align:start position:0% +the way I'll try to explain to why you + + + align:start position:0% +the way I'll try to explain to why you +never want to do that theistic value at + + align:start position:0% +never want to do that theistic value at + + + align:start position:0% +never want to do that theistic value at +any given node + + align:start position:0% +any given node + + + align:start position:0% +any given node +says given that I'm here how much work + + align:start position:0% +says given that I'm here how much work + + + align:start position:0% +says given that I'm here how much work +do I think I have left to get to the end + + align:start position:0% +do I think I have left to get to the end + + + align:start position:0% +do I think I have left to get to the end +all right it's sort of like let's guess + + align:start position:0% +all right it's sort of like let's guess + + + align:start position:0% +all right it's sort of like let's guess +the last few nodes in the path that we + + align:start position:0% +the last few nodes in the path that we + + + align:start position:0% +the last few nodes in the path that we +haven't done out yet so you can see why + + align:start position:0% +haven't done out yet so you can see why + + + align:start position:0% +haven't done out yet so you can see why +it would be bad to add that every add + + align:start position:0% +it would be bad to add that every add + + + align:start position:0% +it would be bad to add that every add +that for every node in your list because + + align:start position:0% +that for every node in your list because + + + align:start position:0% +that for every node in your list because +then you're at you're double counting + + align:start position:0% +then you're at you're double counting + + + align:start position:0% +then you're at you're double counting +all the last nodes so add the path so + + align:start position:0% +all the last nodes so add the path so + + + align:start position:0% +all the last nodes so add the path so +far to the very finalistic that's 3 plus + + align:start position:0% +far to the very finalistic that's 3 plus + + + align:start position:0% +far to the very finalistic that's 3 plus +4 plus the 50 that's with D is 57 so our + + align:start position:0% +4 plus the 50 that's with D is 57 so our + + + align:start position:0% +4 plus the 50 that's with D is 57 so our +current winner then + + align:start position:0% +current winner then + + + align:start position:0% +current winner then +is 54 with f just same as last time F + + align:start position:0% +is 54 with f just same as last time F + + + align:start position:0% +is 54 with f just same as last time F +goes to + + align:start position:0% +goes to + + + align:start position:0% +goes to +h and what's our total value at + + align:start position:0% +h and what's our total value at + + + align:start position:0% +h and what's our total value at +H 20 plus that's a 39 + + align:start position:0% +H 20 plus that's a 39 + + + align:start position:0% +H 20 plus that's a 39 +59 so who wins now D with + + align:start position:0% +59 so who wins now D with + + + align:start position:0% +59 so who wins now D with +57 but uh we extended F yes good all + + align:start position:0% +57 but uh we extended F yes good all + + + align:start position:0% +57 but uh we extended F yes good all +right so D with 57 all right so d was + + align:start position:0% +right so D with 57 all right so d was + + + align:start position:0% +right so D with 57 all right so d was +not one of the ones that I tricked + + align:start position:0% +not one of the ones that I tricked + + + align:start position:0% +not one of the ones that I tricked +myself with d only goes to + + align:start position:0% +myself with d only goes to + + + align:start position:0% +myself with d only goes to +I what's our value at + + align:start position:0% + + + + align:start position:0% + +I I think our value is 57 because I has + + align:start position:0% +I I think our value is 57 because I has + + + align:start position:0% +I I think our value is 57 because I has +a hero stick of + + align:start position:0% +a hero stick of + + + align:start position:0% +a hero stick of +zero yes I has a hero stick of zero our + + align:start position:0% +zero yes I has a hero stick of zero our + + + align:start position:0% +zero yes I has a hero stick of zero our +value at I is + + align:start position:0% +value at I is + + + align:start position:0% +value at I is +57 okay and I extended D who's the + + align:start position:0% +57 okay and I extended D who's the + + + align:start position:0% +57 okay and I extended D who's the +winner now I okay so I is the winner + + align:start position:0% +winner now I okay so I is the winner + + + align:start position:0% +winner now I okay so I is the winner +with i as a winner we extend I I goes to + + align:start position:0% +with i as a winner we extend I I goes to + + + align:start position:0% +with i as a winner we extend I I goes to +c d haha good call whoever back there + + align:start position:0% +c d haha good call whoever back there + + + align:start position:0% +c d haha good call whoever back there +figured out my secret error before CD + + align:start position:0% +figured out my secret error before CD + + + align:start position:0% +figured out my secret error before CD +and + + align:start position:0% +and + + + align:start position:0% +and +g c h and + + align:start position:0% +g c h and + + + align:start position:0% +g c h and +G oh you're right we already went to D + + align:start position:0% +G oh you're right we already went to D + + + align:start position:0% +G oh you're right we already went to D +aha c h and G you're + + align:start position:0% +aha c h and G you're + + + align:start position:0% +aha c h and G you're +correct everyone see that CH H and G + + align:start position:0% +correct everyone see that CH H and G + + + align:start position:0% +correct everyone see that CH H and G +absolutely right I goes to CH H and G so + + align:start position:0% +absolutely right I goes to CH H and G so + + + align:start position:0% +absolutely right I goes to CH H and G so +the path to see h& G is is a is a hard + + align:start position:0% +the path to see h& G is is a is a hard + + + align:start position:0% +the path to see h& G is is a is a hard +path um we've got to see we got what did + + align:start position:0% +path um we've got to see we got what did + + + align:start position:0% +path um we've got to see we got what did +we have 57 + 50 is + + align:start position:0% +we have 57 + 50 is + + + align:start position:0% +we have 57 + 50 is +127 oh and by way c g and H we've got to + + align:start position:0% +127 oh and by way c g and H we've got to + + + align:start position:0% +127 oh and by way c g and H we've got to +do it in L graphic order so 127 to C to + + align:start position:0% +do it in L graphic order so 127 to C to + + + align:start position:0% +do it in L graphic order so 127 to C to +G we have + + align:start position:0% +G we have + + + align:start position:0% +G we have +67 and to H we + + align:start position:0% +67 and to H we + + + align:start position:0% +67 and to H we +have + + align:start position:0% +have + + + align:start position:0% +have +87 okay so who wins + + align:start position:0% + + + + align:start position:0% + +now H H with 59 that's right + + align:start position:0% +now H H with 59 that's right + + + align:start position:0% +now H H with 59 that's right +H with 59 and as we already know because + + align:start position:0% +H with 59 and as we already know because + + + align:start position:0% +H with 59 and as we already know because +it was the winner last time H with 59 + + align:start position:0% +it was the winner last time H with 59 + + + align:start position:0% +it was the winner last time H with 59 +goes to + + align:start position:0% + + + + align:start position:0% + +I which has I believe um + + align:start position:0% + + + + align:start position:0% + +50 well it still gets added remember + + align:start position:0% +50 well it still gets added remember + + + align:start position:0% +50 well it still gets added remember +we're only going to kill it when it gets + + align:start position:0% +we're only going to kill it when it gets + + + align:start position:0% +we're only going to kill it when it gets +extended so who's the shortest so you a + + align:start position:0% +extended so who's the shortest so you a + + + align:start position:0% +extended so who's the shortest so you a +step ahead whoever asked me the question + + align:start position:0% +step ahead whoever asked me the question + + + align:start position:0% +step ahead whoever asked me the question +who's the shortest H also goes to e h + + align:start position:0% +who's the shortest H also goes to e h + + + align:start position:0% +who's the shortest H also goes to e h +also goes to E absolutely right all + + align:start position:0% +also goes to E absolutely right all + + + align:start position:0% +also goes to E absolutely right all +right H also goes to E I was getting + + align:start position:0% +right H also goes to E I was getting + + + align:start position:0% +right H also goes to E I was getting +ahead of myself here H also goes to e + + align:start position:0% +ahead of myself here H also goes to e + + + align:start position:0% +ahead of myself here H also goes to e +with a length of extra 16 so we've got a + + align:start position:0% +with a length of extra 16 so we've got a + + + align:start position:0% +with a length of extra 16 so we've got a +20 + 16 is 36 + 56 is + + align:start position:0% +20 + 16 is 36 + 56 is + + + align:start position:0% +20 + 16 is 36 + 56 is +92 all right that's + + align:start position:0% +92 all right that's + + + align:start position:0% +92 all right that's +good so who's the + + align:start position:0% +good so who's the + + + align:start position:0% +good so who's the +shortest I is the shortest do we extend + + align:start position:0% +shortest I is the shortest do we extend + + + align:start position:0% +shortest I is the shortest do we extend +it no it's on the extended + + align:start position:0% +it no it's on the extended + + + align:start position:0% +it no it's on the extended +list all right who's the shortest + + align:start position:0% +list all right who's the shortest + + + align:start position:0% +list all right who's the shortest +now it's hard to read but the shortest + + align:start position:0% +now it's hard to read but the shortest + + + align:start position:0% +now it's hard to read but the shortest +is this 67 on the G so we're done we win + + align:start position:0% +is this 67 on the G so we're done we win + + + align:start position:0% +is this 67 on the G so we're done we win +our path is SBD i g yay for a star gets + + align:start position:0% +our path is SBD i g yay for a star gets + + + align:start position:0% +our path is SBD i g yay for a star gets +the right answer right + + align:start position:0% +the right answer right + + + align:start position:0% +the right answer right +no ah unfortunately not so what happened + + align:start position:0% +no ah unfortunately not so what happened + + + align:start position:0% +no ah unfortunately not so what happened +here why did we not get the right answer + + align:start position:0% +here why did we not get the right answer + + + align:start position:0% +here why did we not get the right answer +be as specific as + + align:start position:0% + + + + align:start position:0% + +possible what are people saying about + + align:start position:0% +possible what are people saying about + + + align:start position:0% +possible what are people saying about +heris + + align:start position:0% +heris + + + align:start position:0% +heris +sixs all right people are saying + + align:start position:0% +sixs all right people are saying + + + align:start position:0% +sixs all right people are saying +theistic must be consistent that is both + + align:start position:0% +theistic must be consistent that is both + + + align:start position:0% +theistic must be consistent that is both +correct and specific spefic so I applaud + + align:start position:0% +correct and specific spefic so I applaud + + + align:start position:0% +correct and specific spefic so I applaud +you too easy to say theistic was UN + + align:start position:0% +you too easy to say theistic was UN + + + align:start position:0% +you too easy to say theistic was UN +admissible it actually was completely + + align:start position:0% +admissible it actually was completely + + + align:start position:0% +admissible it actually was completely +admissible everywhere so that leads us + + align:start position:0% +admissible everywhere so that leads us + + + align:start position:0% +admissible everywhere so that leads us +into our very last point for the day + + align:start position:0% +into our very last point for the day + + + align:start position:0% +into our very last point for the day +what the hell are these juristic + + align:start position:0% +what the hell are these juristic + + + align:start position:0% +what the hell are these juristic +consistency and admissibility things and + + align:start position:0% +consistency and admissibility things and + + + align:start position:0% +consistency and admissibility things and +why do I care well the reason why you + + align:start position:0% +why do I care well the reason why you + + + align:start position:0% +why do I care well the reason why you +care is manyfold one of which is that + + align:start position:0% +care is manyfold one of which is that + + + align:start position:0% +care is manyfold one of which is that +it's almost guaranteed to be on the quiz + + align:start position:0% +it's almost guaranteed to be on the quiz + + + align:start position:0% +it's almost guaranteed to be on the quiz +but what are they admissibility is a + + align:start position:0% +but what are they admissibility is a + + + align:start position:0% +but what are they admissibility is a +check at every point to make sure your + + align:start position:0% +check at every point to make sure your + + + align:start position:0% +check at every point to make sure your +ceris at that point which is supposed to + + align:start position:0% +ceris at that point which is supposed to + + + align:start position:0% +ceris at that point which is supposed to +be an estimate of how much work you have + + align:start position:0% +be an estimate of how much work you have + + + align:start position:0% +be an estimate of how much work you have +left to do is always an under estimate + + align:start position:0% +left to do is always an under estimate + + + align:start position:0% +left to do is always an under estimate +or an accurate estimate it can never be + + align:start position:0% +or an accurate estimate it can never be + + + align:start position:0% +or an accurate estimate it can never be +an overestimate why not well as Patrick + + align:start position:0% +an overestimate why not well as Patrick + + + align:start position:0% +an overestimate why not well as Patrick +showed you with his mostly correct + + align:start position:0% +showed you with his mostly correct + + + align:start position:0% +showed you with his mostly correct +example on in lecture if it's an + + align:start position:0% +example on in lecture if it's an + + + align:start position:0% +example on in lecture if it's an +overestimate it's never going to expand + + align:start position:0% +overestimate it's never going to expand + + + align:start position:0% +overestimate it's never going to expand +that node because it's going to think + + align:start position:0% +that node because it's going to think + + + align:start position:0% +that node because it's going to think +you know if you write 1 million as a + + align:start position:0% +you know if you write 1 million as a + + + align:start position:0% +you know if you write 1 million as a +heuristic it's going to think it needs + + align:start position:0% +heuristic it's going to think it needs + + + align:start position:0% +heuristic it's going to think it needs +to do 1 million after it's done going + + align:start position:0% +to do 1 million after it's done going + + + align:start position:0% +to do 1 million after it's done going +that way it's not going to want to go + + align:start position:0% +that way it's not going to want to go + + + align:start position:0% +that way it's not going to want to go +that way all right so it's always got to + + align:start position:0% +that way all right so it's always got to + + + align:start position:0% +that way all right so it's always got to +be an underestimate or an equal estimate + + align:start position:0% +be an underestimate or an equal estimate + + + align:start position:0% +be an underestimate or an equal estimate +but let's say that you as at the quiz + + align:start position:0% +but let's say that you as at the quiz + + + align:start position:0% +but let's say that you as at the quiz +and you forget Mark told me this you + + align:start position:0% +and you forget Mark told me this you + + + align:start position:0% +and you forget Mark told me this you +didn't bring any notes you're just + + align:start position:0% +didn't bring any notes you're just + + + align:start position:0% +didn't bring any notes you're just +having a brain free oh know is it + + align:start position:0% +having a brain free oh know is it + + + align:start position:0% +having a brain free oh know is it +supposed to be an overestimate or an + + align:start position:0% +supposed to be an overestimate or an + + + align:start position:0% +supposed to be an overestimate or an +under estimate I can't remember which + + align:start position:0% +under estimate I can't remember which + + + align:start position:0% +under estimate I can't remember which +one how can I figure it out how can I + + align:start position:0% +one how can I figure it out how can I + + + align:start position:0% +one how can I figure it out how can I +figure it out I propose you the + + align:start position:0% +figure it out I propose you the + + + align:start position:0% +figure it out I propose you the +following calm soothing Mantra Sutra + + align:start position:0% +following calm soothing Mantra Sutra + + + align:start position:0% +following calm soothing Mantra Sutra +that will help protect you think to + + align:start position:0% +that will help protect you think to + + + align:start position:0% +that will help protect you think to +yourself of the following question does + + align:start position:0% +yourself of the following question does + + + align:start position:0% +yourself of the following question does +we know that a star sometimes messes up + + align:start position:0% +we know that a star sometimes messes up + + + align:start position:0% +we know that a star sometimes messes up +with the heuristic does branch and bound + + align:start position:0% +with the heuristic does branch and bound + + + align:start position:0% +with the heuristic does branch and bound +always get it right yes what heuristic + + align:start position:0% +always get it right yes what heuristic + + + align:start position:0% +always get it right yes what heuristic +values does branch and bound add + + align:start position:0% +values does branch and bound add + + + align:start position:0% +values does branch and bound add +everywhere zero right it has no heris + + align:start position:0% +everywhere zero right it has no heris + + + align:start position:0% +everywhere zero right it has no heris +get essentially add zero is zero an + + align:start position:0% +get essentially add zero is zero an + + + align:start position:0% +get essentially add zero is zero an +overestimate or underestimate an + + align:start position:0% +overestimate or underestimate an + + + align:start position:0% +overestimate or underestimate an +underestimate therefore since branch and + + align:start position:0% +underestimate therefore since branch and + + + align:start position:0% +underestimate therefore since branch and +bound always works the one you're + + align:start position:0% +bound always works the one you're + + + align:start position:0% +bound always works the one you're +looking for is underestimate I know from + + align:start position:0% +looking for is underestimate I know from + + + align:start position:0% +looking for is underestimate I know from +when I was taking the class I always had + + align:start position:0% +when I was taking the class I always had + + + align:start position:0% +when I was taking the class I always had +a moment where I had to spend like two + + align:start position:0% +a moment where I had to spend like two + + + align:start position:0% +a moment where I had to spend like two +minutes convincing myself okay I'm going + + align:start position:0% +minutes convincing myself okay I'm going + + + align:start position:0% +minutes convincing myself okay I'm going +for underestimate not overestimate this + + align:start position:0% +for underestimate not overestimate this + + + align:start position:0% +for underestimate not overestimate this +will help it will take fewer than two + + align:start position:0% +will help it will take fewer than two + + + align:start position:0% +will help it will take fewer than two +minutes to do that so what is + + align:start position:0% +minutes to do that so what is + + + align:start position:0% +minutes to do that so what is +consistency consistency is a Little Bit + + align:start position:0% +consistency consistency is a Little Bit + + + align:start position:0% +consistency consistency is a Little Bit +Stronger of a claim when you claim that + + align:start position:0% +Stronger of a claim when you claim that + + + align:start position:0% +Stronger of a claim when you claim that +a graph is consistent what you're saying + + align:start position:0% +a graph is consistent what you're saying + + + align:start position:0% +a graph is consistent what you're saying +is between any two nodes or to do it + + align:start position:0% +is between any two nodes or to do it + + + align:start position:0% +is between any two nodes or to do it +more simply between any two adjacent + + align:start position:0% +more simply between any two adjacent + + + align:start position:0% +more simply between any two adjacent +nodes the distance between the + + align:start position:0% +nodes the distance between the + + + align:start position:0% +nodes the distance between the +heuristics is less than the distance + + align:start position:0% +heuristics is less than the distance + + + align:start position:0% +heuristics is less than the distance +between the nodes in other words it's + + align:start position:0% +between the nodes in other words it's + + + align:start position:0% +between the nodes in other words it's +sort of like admissibility is this sort + + align:start position:0% +sort of like admissibility is this sort + + + align:start position:0% +sort of like admissibility is this sort +of like consistency between every node + + align:start position:0% +of like consistency between every node + + + align:start position:0% +of like consistency between every node +and G whereas consistency is consistency + + align:start position:0% +and G whereas consistency is consistency + + + align:start position:0% +and G whereas consistency is consistency +between every node in every other node + + align:start position:0% +between every node in every other node + + + align:start position:0% +between every node in every other node +all right consistency is a stronger + + align:start position:0% +all right consistency is a stronger + + + align:start position:0% +all right consistency is a stronger +claim any graph that's consistent is + + align:start position:0% +claim any graph that's consistent is + + + align:start position:0% +claim any graph that's consistent is +always admissible any graph that is + + align:start position:0% +always admissible any graph that is + + + align:start position:0% +always admissible any graph that is +inadmissible is always inconsistent + + align:start position:0% +inadmissible is always inconsistent + + + align:start position:0% +inadmissible is always inconsistent +that's the Contra positive + + align:start position:0% +that's the Contra positive + + + align:start position:0% +that's the Contra positive +L equal to is still okay equal to is + + align:start position:0% +L equal to is still okay equal to is + + + align:start position:0% +L equal to is still okay equal to is +always okay that's great it's a perfect + + align:start position:0% +always okay that's great it's a perfect + + + align:start position:0% +always okay that's great it's a perfect +estimate but never greater now if a + + align:start position:0% +estimate but never greater now if a + + + align:start position:0% +estimate but never greater now if a +graph is inconsistent will you lose will + + align:start position:0% +graph is inconsistent will you lose will + + + align:start position:0% +graph is inconsistent will you lose will +you lose why is it called admissible + + align:start position:0% +you lose why is it called admissible + + + align:start position:0% +you lose why is it called admissible +then if you can if if if it's sometimes + + align:start position:0% +then if you can if if if it's sometimes + + + align:start position:0% +then if you can if if if it's sometimes +not admissible the answer is why do why + + align:start position:0% +not admissible the answer is why do why + + + align:start position:0% +not admissible the answer is why do why +do we lose the answer is the extended + + align:start position:0% +do we lose the answer is the extended + + + align:start position:0% +do we lose the answer is the extended +list and you see that here if a graph is + + align:start position:0% +list and you see that here if a graph is + + + align:start position:0% +list and you see that here if a graph is +admissible you will always get the right + + align:start position:0% +admissible you will always get the right + + + align:start position:0% +admissible you will always get the right +answer and uh you'll always get the + + align:start position:0% +answer and uh you'll always get the + + + align:start position:0% +answer and uh you'll always get the +right answer unless you use an extended + + align:start position:0% +right answer unless you use an extended + + + align:start position:0% +right answer unless you use an extended +list because you're checking for from + + align:start position:0% +list because you're checking for from + + + align:start position:0% +list because you're checking for from +every node to the goal node and you're + + align:start position:0% +every node to the goal node and you're + + + align:start position:0% +every node to the goal node and you're +sure that your estimates are right but + + align:start position:0% +sure that your estimates are right but + + + align:start position:0% +sure that your estimates are right but +if estimates within nodes aren't correct + + align:start position:0% +if estimates within nodes aren't correct + + + align:start position:0% +if estimates within nodes aren't correct +you might go through them out of order + + align:start position:0% +you might go through them out of order + + + align:start position:0% +you might go through them out of order +and that violates your assumption that + + align:start position:0% +and that violates your assumption that + + + align:start position:0% +and that violates your assumption that +you made when you decide to use the + + align:start position:0% +you made when you decide to use the + + + align:start position:0% +you made when you decide to use the +extended list that you would always go + + align:start position:0% +extended list that you would always go + + + align:start position:0% +extended list that you would always go +through the sort of the subgraphs in + + align:start position:0% +through the sort of the subgraphs in + + + align:start position:0% +through the sort of the subgraphs in +order this graph is very expertly + + align:start position:0% +order this graph is very expertly + + + align:start position:0% +order this graph is very expertly +crafted to do that to you because I + + align:start position:0% +crafted to do that to you because I + + + align:start position:0% +crafted to do that to you because I +might as well be sort of a bottleneck + + align:start position:0% +might as well be sort of a bottleneck + + + align:start position:0% +might as well be sort of a bottleneck +goal node and I has an inconsistency + + align:start position:0% +goal node and I has an inconsistency + + + align:start position:0% +goal node and I has an inconsistency +there's a few other inconsistencies in + + align:start position:0% +there's a few other inconsistencies in + + + align:start position:0% +there's a few other inconsistencies in +this graph but they don't do anything to + + align:start position:0% +this graph but they don't do anything to + + + align:start position:0% +this graph but they don't do anything to +you in fact even eiss abilities + + align:start position:0% +you in fact even eiss abilities + + + align:start position:0% +you in fact even eiss abilities +sometimes don't mess you up so you can't + + align:start position:0% +sometimes don't mess you up so you can't + + + align:start position:0% +sometimes don't mess you up so you can't +just say blindly it's in admissible so + + align:start position:0% +just say blindly it's in admissible so + + + align:start position:0% +just say blindly it's in admissible so +it will never work it might work it + + align:start position:0% +it will never work it might work it + + + align:start position:0% +it will never work it might work it +turns out the only inconsistency that + + align:start position:0% +turns out the only inconsistency that + + + align:start position:0% +turns out the only inconsistency that +matters here is not the inconsistency + + align:start position:0% +matters here is not the inconsistency + + + align:start position:0% +matters here is not the inconsistency +between say s and and f that doesn't + + align:start position:0% +between say s and and f that doesn't + + + align:start position:0% +between say s and and f that doesn't +turn out to matter it's the + + align:start position:0% +turn out to matter it's the + + + align:start position:0% +turn out to matter it's the +inconsistency between um some of these + + align:start position:0% +inconsistency between um some of these + + + align:start position:0% +inconsistency between um some of these +nodes including I and H specifically + + align:start position:0% +nodes including I and H specifically + + + align:start position:0% +nodes including I and H specifically +so have a good weekend come in on Monday + + align:start position:0% +so have a good weekend come in on Monday + + + align:start position:0% +so have a good weekend come in on Monday +and Tuesday the tutorial ask about the Q + + align:start position:0% +and Tuesday the tutorial ask about the Q + + + align:start position:0% +and Tuesday the tutorial ask about the Q +method or or other methods ask about + + align:start position:0% +method or or other methods ask about + + + align:start position:0% +method or or other methods ask about +anything that's ningling in your brain + + align:start position:0% +anything that's ningling in your brain + + + align:start position:0% +anything that's ningling in your brain +but hopefully you guys have got this + + align:start position:0% +but hopefully you guys have got this + + + align:start position:0% +but hopefully you guys have got this +you're going to do fine \ No newline at end of file diff --git a/TnS8kI_KuJc.txt b/TnS8kI_KuJc.txt new file mode 100644 index 0000000000000000000000000000000000000000..c171e1731f9862ec9ecc36f4e119befa044fa2bf --- /dev/null +++ b/TnS8kI_KuJc.txt @@ -0,0 +1,6747 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT OpenCourseWare continue to + + align:start position:0% +will help MIT OpenCourseWare continue to + + + align:start position:0% +will help MIT OpenCourseWare continue to +offer high quality educational resources + + align:start position:0% +offer high quality educational resources + + + align:start position:0% +offer high quality educational resources +for free + + align:start position:0% +for free + + + align:start position:0% +for free +to make a donation or view additional + + align:start position:0% +to make a donation or view additional + + + align:start position:0% +to make a donation or view additional +materials from hundreds of MIT courses + + align:start position:0% +materials from hundreds of MIT courses + + + align:start position:0% +materials from hundreds of MIT courses +visit MIT opencourseware at ocw.mit.edu + + align:start position:0% + + + + align:start position:0% + +so let's start with with a simple but + + align:start position:0% +so let's start with with a simple but + + + align:start position:0% +so let's start with with a simple but +quite illustrative example so suppose + + align:start position:0% +quite illustrative example so suppose + + + align:start position:0% +quite illustrative example so suppose +you're a bookie and what bookie does he + + align:start position:0% +you're a bookie and what bookie does he + + + align:start position:0% +you're a bookie and what bookie does he +accept bet on on on the horses sets the + + align:start position:0% +accept bet on on on the horses sets the + + + align:start position:0% +accept bet on on on the horses sets the +odds and then pays money back + + align:start position:0% +odds and then pays money back + + + align:start position:0% +odds and then pays money back +probably collects a fee somewhere in + + align:start position:0% +probably collects a fee somewhere in + + + align:start position:0% +probably collects a fee somewhere in +between so suppose it is a good bookie + + align:start position:0% +between so suppose it is a good bookie + + + align:start position:0% +between so suppose it is a good bookie +and he knows quite well the horses and + + align:start position:0% +and he knows quite well the horses and + + + align:start position:0% +and he knows quite well the horses and +there are two horses one horse has he + + align:start position:0% +there are two horses one horse has he + + + align:start position:0% +there are two horses one horse has he +knows that for sure one horse has twenty + + align:start position:0% +knows that for sure one horse has twenty + + + align:start position:0% +knows that for sure one horse has twenty +percent chance of winning in another + + align:start position:0% +percent chance of winning in another + + + align:start position:0% +percent chance of winning in another +horses eighty percent chance of winning + + align:start position:0% +horses eighty percent chance of winning + + + align:start position:0% +horses eighty percent chance of winning +obviously general public doesn't have + + align:start position:0% +obviously general public doesn't have + + + align:start position:0% +obviously general public doesn't have +all these information so they place a + + align:start position:0% +all these information so they place a + + + align:start position:0% +all these information so they place a +bet slightly differently and at the end + + align:start position:0% +bet slightly differently and at the end + + + align:start position:0% +bet slightly differently and at the end +there is ten thousand bet on one horse + + align:start position:0% +there is ten thousand bet on one horse + + + align:start position:0% +there is ten thousand bet on one horse +and fifty thousand bet on the another + + align:start position:0% +and fifty thousand bet on the another + + + align:start position:0% +and fifty thousand bet on the another +horse + + align:start position:0% +horse + + + align:start position:0% +horse +well bookie is sure that he possesses + + align:start position:0% +well bookie is sure that he possesses + + + align:start position:0% +well bookie is sure that he possesses +good information so he suppose he sets + + align:start position:0% +good information so he suppose he sets + + + align:start position:0% +good information so he suppose he sets +the odds according to the real real-life + + align:start position:0% +the odds according to the real real-life + + + align:start position:0% +the odds according to the real real-life +probabilities so he says at four to one + + align:start position:0% +probabilities so he says at four to one + + + align:start position:0% +probabilities so he says at four to one +what would be possible outcomes of the + + align:start position:0% +what would be possible outcomes of the + + + align:start position:0% +what would be possible outcomes of the +race for him monetary so suppose the + + align:start position:0% +race for him monetary so suppose the + + + align:start position:0% +race for him monetary so suppose the +first horse wins then what happens he he + + align:start position:0% +first horse wins then what happens he he + + + align:start position:0% +first horse wins then what happens he he +has to pay back ten thousand then four + + align:start position:0% +has to pay back ten thousand then four + + + align:start position:0% +has to pay back ten thousand then four +times more so he pays out fifty thousand + + align:start position:0% +times more so he pays out fifty thousand + + + align:start position:0% +times more so he pays out fifty thousand +and he received 60 right so he can keep + + align:start position:0% +and he received 60 right so he can keep + + + align:start position:0% +and he received 60 right so he can keep +ten thousand out of it okay so what + + align:start position:0% +ten thousand out of it okay so what + + + align:start position:0% +ten thousand out of it okay so what +happens is there are the other more + + align:start position:0% +happens is there are the other more + + + align:start position:0% +happens is there are the other more +probable horse wins + + align:start position:0% +probable horse wins + + + align:start position:0% +probable horse wins +well he'll you have to pay back the + + align:start position:0% +well he'll you have to pay back the + + + align:start position:0% +well he'll you have to pay back the +fifty thousand and one quarter of it + + align:start position:0% +fifty thousand and one quarter of it + + + align:start position:0% +fifty thousand and one quarter of it +which is twelve and twelve twenty five + + align:start position:0% +which is twelve and twelve twenty five + + + align:start position:0% +which is twelve and twelve twenty five +so at the end he'll pay sixty two and a + + align:start position:0% +so at the end he'll pay sixty two and a + + + align:start position:0% +so at the end he'll pay sixty two and a +half thousand while he collected 67 + + align:start position:0% +half thousand while he collected 67 + + + align:start position:0% +half thousand while he collected 67 +right so he will in this situation he'll + + align:start position:0% +right so he will in this situation he'll + + + align:start position:0% +right so he will in this situation he'll +lose + + align:start position:0% + + + + align:start position:0% + +$2,500 well all in all he expects to + + align:start position:0% +$2,500 well all in all he expects to + + + align:start position:0% +$2,500 well all in all he expects to +make nothing so he probably could + + align:start position:0% +make nothing so he probably could + + + align:start position:0% +make nothing so he probably could +collect enough fees to cover his + + align:start position:0% +collect enough fees to cover his + + + align:start position:0% +collect enough fees to cover his +potential loss but there is certainly a + + align:start position:0% +potential loss but there is certainly a + + + align:start position:0% +potential loss but there is certainly a +very variable + + align:start position:0% +very variable + + + align:start position:0% +very variable +in outcomes he can win a lot he can lose + + align:start position:0% +in outcomes he can win a lot he can lose + + + align:start position:0% +in outcomes he can win a lot he can lose +some now + + align:start position:0% +some now + + + align:start position:0% +some now +what if he forgets about his knowledge + + align:start position:0% +what if he forgets about his knowledge + + + align:start position:0% +what if he forgets about his knowledge +about the real real life probabilities + + align:start position:0% +about the real real life probabilities + + + align:start position:0% +about the real real life probabilities +of horses winning or losing and instead + + align:start position:0% +of horses winning or losing and instead + + + align:start position:0% +of horses winning or losing and instead +set the bet according to to the amount + + align:start position:0% +set the bet according to to the amount + + + align:start position:0% +set the bet according to to the amount +which were already bet according to the + + align:start position:0% +which were already bet according to the + + + align:start position:0% +which were already bet according to the +market effectively so what if he sets + + align:start position:0% +market effectively so what if he sets + + + align:start position:0% +market effectively so what if he sets +the better the odds five to one + + align:start position:0% +the better the odds five to one + + + align:start position:0% +the better the odds five to one +according to the bets placed well in + + align:start position:0% +according to the bets placed well in + + + align:start position:0% +according to the bets placed well in +this situation is the first horse wins + + align:start position:0% +this situation is the first horse wins + + + align:start position:0% +this situation is the first horse wins +he pays back ten plus five times ten so + + align:start position:0% +he pays back ten plus five times ten so + + + align:start position:0% +he pays back ten plus five times ten so +sixty he is zero and if the second horse + + align:start position:0% +sixty he is zero and if the second horse + + + align:start position:0% +sixty he is zero and if the second horse +wins he pays back fifty plus one-fifth + + align:start position:0% +wins he pays back fifty plus one-fifth + + + align:start position:0% +wins he pays back fifty plus one-fifth +of fifty plus another ten again 60 so no + + align:start position:0% +of fifty plus another ten again 60 so no + + + align:start position:0% +of fifty plus another ten again 60 so no +matter which were horse wins he will get + + align:start position:0% +matter which were horse wins he will get + + + align:start position:0% +matter which were horse wins he will get +zero with hunger potential and if he + + align:start position:0% +zero with hunger potential and if he + + + align:start position:0% +zero with hunger potential and if he +collects collects some fee on top of it + + align:start position:0% +collects collects some fee on top of it + + + align:start position:0% +collects collects some fee on top of it +he will make a riskless profit and + + align:start position:0% +he will make a riskless profit and + + + align:start position:0% +he will make a riskless profit and +that's how actually bookies are + + align:start position:0% +that's how actually bookies are + + + align:start position:0% +that's how actually bookies are +operating so it's a simple example but + + align:start position:0% +operating so it's a simple example but + + + align:start position:0% +operating so it's a simple example but +it gives us a first idea how risk + + align:start position:0% +it gives us a first idea how risk + + + align:start position:0% +it gives us a first idea how risk +neutral framework and risk-neutral + + align:start position:0% +neutral framework and risk-neutral + + + align:start position:0% +neutral framework and risk-neutral +pricing when works so we are here not in + + align:start position:0% +pricing when works so we are here not in + + + align:start position:0% +pricing when works so we are here not in +the business of making bets on horses + + align:start position:0% +the business of making bets on horses + + + align:start position:0% +the business of making bets on horses +we're actually in the business of + + align:start position:0% +we're actually in the business of + + + align:start position:0% +we're actually in the business of +pricing derivatives so we will talk + + align:start position:0% +pricing derivatives so we will talk + + + align:start position:0% +pricing derivatives so we will talk +about the simplest possible derivatives + + align:start position:0% +about the simplest possible derivatives + + + align:start position:0% +about the simplest possible derivatives +mostly derivatives on stocks but there + + align:start position:0% +mostly derivatives on stocks but there + + + align:start position:0% +mostly derivatives on stocks but there +there are more complicated derivatives + + align:start position:0% +there are more complicated derivatives + + + align:start position:0% +there are more complicated derivatives +which underline for which could be + + align:start position:0% +which underline for which could be + + + align:start position:0% +which underline for which could be +interest rates bond swaps commodities + + align:start position:0% +interest rates bond swaps commodities + + + align:start position:0% +interest rates bond swaps commodities +whatever so derivative contract is some + + align:start position:0% +whatever so derivative contract is some + + + align:start position:0% +whatever so derivative contract is some +in general a general speaking a formal + + align:start position:0% +in general a general speaking a formal + + + align:start position:0% +in general a general speaking a formal +payout connected to underline usually + + align:start position:0% +payout connected to underline usually + + + align:start position:0% +payout connected to underline usually +the underlying is a liquid instrument + + align:start position:0% +the underlying is a liquid instrument + + + align:start position:0% +the underlying is a liquid instrument +which is traded traded on exchanges and + + align:start position:0% +which is traded traded on exchanges and + + + align:start position:0% +which is traded traded on exchanges and +derivative may be traded on exchanges + + align:start position:0% +derivative may be traded on exchanges + + + align:start position:0% +derivative may be traded on exchanges +actually quite a few equity options are + + align:start position:0% +actually quite a few equity options are + + + align:start position:0% +actually quite a few equity options are +trade exchanges but in general they're + + align:start position:0% +trade exchanges but in general they're + + + align:start position:0% +trade exchanges but in general they're +over-the-counter over-the-counter + + align:start position:0% +over-the-counter over-the-counter + + + align:start position:0% +over-the-counter over-the-counter +contracts where two counterparties just + + align:start position:0% +contracts where two counterparties just + + + align:start position:0% +contracts where two counterparties just +agree on some kind of payout + + align:start position:0% +agree on some kind of payout + + + align:start position:0% +agree on some kind of payout +one of the simpler derivatives is is a + + align:start position:0% +one of the simpler derivatives is is a + + + align:start position:0% +one of the simpler derivatives is is a +forward contract so what is a forward + + align:start position:0% +forward contract so what is a forward + + + align:start position:0% +forward contract so what is a forward +contract for a contract is a contract + + align:start position:0% +contract for a contract is a contract + + + align:start position:0% +contract for a contract is a contract +where one party agrees to buy an asset + + align:start position:0% +where one party agrees to buy an asset + + + align:start position:0% +where one party agrees to buy an asset +from another party for a price which is + + align:start position:0% +from another party for a price which is + + + align:start position:0% +from another party for a price which is +agreed today usually the this contract + + align:start position:0% +agreed today usually the this contract + + + align:start position:0% +agreed today usually the this contract +has this forward price is is set in such + + align:start position:0% +has this forward price is is set in such + + + align:start position:0% +has this forward price is is set in such +a way that right now no money changes + + align:start position:0% +a way that right now no money changes + + + align:start position:0% +a way that right now no money changes +hands right so and here here is an + + align:start position:0% +hands right so and here here is an + + + align:start position:0% +hands right so and here here is an +example well suppose there is a stock + + align:start position:0% +example well suppose there is a stock + + + align:start position:0% +example well suppose there is a stock +which right now is priced at 80 and this + + align:start position:0% +which right now is priced at 80 and this + + + align:start position:0% +which right now is priced at 80 and this +is the forward for two years so somebody + + align:start position:0% +is the forward for two years so somebody + + + align:start position:0% +is the forward for two years so somebody +agrees to buy this stock in two years + + align:start position:0% +agrees to buy this stock in two years + + + align:start position:0% +agrees to buy this stock in two years +for this price and not surprisingly I + + align:start position:0% +for this price and not surprisingly I + + + align:start position:0% +for this price and not surprisingly I +somehow set this price such that + + align:start position:0% +somehow set this price such that + + + align:start position:0% +somehow set this price such that +currently the value the value of the + + align:start position:0% +currently the value the value of the + + + align:start position:0% +currently the value the value of the +contract is zero and we'll see how I'll + + align:start position:0% +contract is zero and we'll see how I'll + + + align:start position:0% +contract is zero and we'll see how I'll +come up with a price so this blue line + + align:start position:0% +come up with a price so this blue line + + + align:start position:0% +come up with a price so this blue line +is actually payout what will happen at + + align:start position:0% +is actually payout what will happen at + + + align:start position:0% +is actually payout what will happen at +the end right the the payout depending + + align:start position:0% +the end right the the payout depending + + + align:start position:0% +the end right the the payout depending +the graph of F at time T to + + align:start position:0% +the graph of F at time T to + + + align:start position:0% +the graph of F at time T to +determination time or expiry how it + + align:start position:0% +determination time or expiry how it + + + align:start position:0% +determination time or expiry how it +depends on the stock price right so + + align:start position:0% +depends on the stock price right so + + + align:start position:0% +depends on the stock price right so +obviously the payout is s minus K where + + align:start position:0% +obviously the payout is s minus K where + + + align:start position:0% +obviously the payout is s minus K where +as as as as the stock price so it's a + + align:start position:0% +as as as as the stock price so it's a + + + align:start position:0% +as as as as the stock price so it's a +linear function it turns out that the + + align:start position:0% +linear function it turns out that the + + + align:start position:0% +linear function it turns out that the +current price is also really no function + + align:start position:0% +current price is also really no function + + + align:start position:0% +current price is also really no function +but slightly shifted and we'll see how + + align:start position:0% +but slightly shifted and we'll see how + + + align:start position:0% +but slightly shifted and we'll see how +how come it slightly shifted and how + + align:start position:0% +how come it slightly shifted and how + + + align:start position:0% +how come it slightly shifted and how +much it should be shifted and K is + + align:start position:0% +much it should be shifted and K is + + + align:start position:0% +much it should be shifted and K is +usually referred as a strike price + + align:start position:0% +usually referred as a strike price + + + align:start position:0% +usually referred as a strike price +another slightly more complicated + + align:start position:0% +another slightly more complicated + + + align:start position:0% +another slightly more complicated +contract is called + + align:start position:0% +contract is called + + + align:start position:0% +contract is called +a call option so if previously the + + align:start position:0% +a call option so if previously the + + + align:start position:0% +a call option so if previously the +forward is is is an obligation to buy + + align:start position:0% +forward is is is an obligation to buy + + + align:start position:0% +forward is is is an obligation to buy +the asset for for an agreed price call + + align:start position:0% +the asset for for an agreed price call + + + align:start position:0% +the asset for for an agreed price call +option is actually an option to buy to + + align:start position:0% +option is actually an option to buy to + + + align:start position:0% +option is actually an option to buy to +buy an asset at the agreed price today + + align:start position:0% +buy an asset at the agreed price today + + + align:start position:0% +buy an asset at the agreed price today +you can view it a call option can be + + align:start position:0% +you can view it a call option can be + + + align:start position:0% +you can view it a call option can be +viewed as kind of insurance that the + + align:start position:0% +viewed as kind of insurance that the + + + align:start position:0% +viewed as kind of insurance that the +against the asset going down basically + + align:start position:0% +against the asset going down basically + + + align:start position:0% +against the asset going down basically +the payout is always pose + + align:start position:0% +the payout is always pose + + + align:start position:0% +the payout is always pose +you can never lose money on the forward + + align:start position:0% +you can never lose money on the forward + + + align:start position:0% +you can never lose money on the forward +you can lose money you agree on the + + align:start position:0% +you can lose money you agree on the + + + align:start position:0% +you can lose money you agree on the +price see the asset ends up being lower + + align:start position:0% +price see the asset ends up being lower + + + align:start position:0% +price see the asset ends up being lower +than this price but you still have to + + align:start position:0% +than this price but you still have to + + + align:start position:0% +than this price but you still have to +buy it right here if if the asset ends + + align:start position:0% +buy it right here if if the asset ends + + + align:start position:0% +buy it right here if if the asset ends +up at expiry below strike price or out + + align:start position:0% +up at expiry below strike price or out + + + align:start position:0% +up at expiry below strike price or out +of the money then the payout will be + + align:start position:0% +of the money then the payout will be + + + align:start position:0% +of the money then the payout will be +zero if on the other hand it it ends up + + align:start position:0% +zero if on the other hand it it ends up + + + align:start position:0% +zero if on the other hand it it ends up +being above a strike price or it is + + align:start position:0% +being above a strike price or it is + + + align:start position:0% +being above a strike price or it is +called + + align:start position:0% +called + + + align:start position:0% +called +the option is in the money then your the + + align:start position:0% +the option is in the money then your the + + + align:start position:0% +the option is in the money then your the +payout will be s minus K as before so in + + align:start position:0% +payout will be s minus K as before so in + + + align:start position:0% +payout will be s minus K as before so in +mathematical terms the the payout is + + align:start position:0% +mathematical terms the the payout is + + + align:start position:0% +mathematical terms the the payout is +maximum of s minus K and zero right and + + align:start position:0% +maximum of s minus K and zero right and + + + align:start position:0% +maximum of s minus K and zero right and +that's what happens at time of at expiry + + align:start position:0% +that's what happens at time of at expiry + + + align:start position:0% +that's what happens at time of at expiry +time this blue line so what is the price + + align:start position:0% +time this blue line so what is the price + + + align:start position:0% +time this blue line so what is the price +of this option now well obviously it it + + align:start position:0% +of this option now well obviously it it + + + align:start position:0% +of this option now well obviously it it +should be slightly both because even if + + align:start position:0% +should be slightly both because even if + + + align:start position:0% +should be slightly both because even if +the if even if now the the asset is + + align:start position:0% +the if even if now the the asset is + + + align:start position:0% +the if even if now the the asset is +slightly out of the money below strike + + align:start position:0% +slightly out of the money below strike + + + align:start position:0% +slightly out of the money below strike +price there is some volatility to it and + + align:start position:0% +price there is some volatility to it and + + + align:start position:0% +price there is some volatility to it and +there is a probability that we will + + align:start position:0% +there is a probability that we will + + + align:start position:0% +there is a probability that we will +still end up in the money at expiry so + + align:start position:0% +still end up in the money at expiry so + + + align:start position:0% +still end up in the money at expiry so +you you would be willing you should be + + align:start position:0% +you you would be willing you should be + + + align:start position:0% +you you would be willing you should be +willing to pay something for this + + align:start position:0% +willing to pay something for this + + + align:start position:0% +willing to pay something for this +obviously if it's way out of the money + + align:start position:0% +obviously if it's way out of the money + + + align:start position:0% +obviously if it's way out of the money +it should be zero right on the other + + align:start position:0% +it should be zero right on the other + + + align:start position:0% +it should be zero right on the other +hand if it's way in the money in fact it + + align:start position:0% +hand if it's way in the money in fact it + + + align:start position:0% +hand if it's way in the money in fact it +should be just as forward and in fact it + + align:start position:0% +should be just as forward and in fact it + + + align:start position:0% +should be just as forward and in fact it +is we will we'll see because if they + + align:start position:0% +is we will we'll see because if they + + + align:start position:0% +is we will we'll see because if they +were the probability for the for the + + align:start position:0% +were the probability for the for the + + + align:start position:0% +were the probability for the for the +asset going back to the strike price and + + align:start position:0% +asset going back to the strike price and + + + align:start position:0% +asset going back to the strike price and +below will be low and that the black + + align:start position:0% +below will be low and that the black + + + align:start position:0% +below will be low and that the black +Scholes equation is black Scholes + + align:start position:0% +Scholes equation is black Scholes + + + align:start position:0% +Scholes equation is black Scholes +formula is exactly the solution for this + + align:start position:0% +formula is exactly the solution for this + + + align:start position:0% +formula is exactly the solution for this +correct line which we'll see in a second + + align:start position:0% +correct line which we'll see in a second + + + align:start position:0% +correct line which we'll see in a second +another simple contract which is kind of + + align:start position:0% +another simple contract which is kind of + + + align:start position:0% +another simple contract which is kind of +dual to call option is a put option so + + align:start position:0% +dual to call option is a put option so + + + align:start position:0% +dual to call option is a put option so +put option on the contrary is a bet on + + align:start position:0% +put option on the contrary is a bet on + + + align:start position:0% +put option on the contrary is a bet on +on the asset going down rather than up + + align:start position:0% +on the asset going down rather than up + + + align:start position:0% +on the asset going down rather than up +right so the payout is maximum of K + + align:start position:0% +right so the payout is maximum of K + + + align:start position:0% +right so the payout is maximum of K +minus s and 0 so it's it's kind of + + align:start position:0% +minus s and 0 so it's it's kind of + + + align:start position:0% +minus s and 0 so it's it's kind of +reversed also a ramp function at the at + + align:start position:0% +reversed also a ramp function at the at + + + align:start position:0% +reversed also a ramp function at the at +maturity + + align:start position:0% +maturity + + + align:start position:0% +maturity +and here here is the current price again + + align:start position:0% +and here here is the current price again + + + align:start position:0% +and here here is the current price again +even if it's in the money if it's way in + + align:start position:0% +even if it's in the money if it's way in + + + align:start position:0% +even if it's in the money if it's way in +the money you expect it to be to be zero + + align:start position:0% +the money you expect it to be to be zero + + + align:start position:0% +the money you expect it to be to be zero +if it's way in the money we expect it to + + align:start position:0% +if it's way in the money we expect it to + + + align:start position:0% +if it's way in the money we expect it to +be slightly below below forward just + + align:start position:0% +be slightly below below forward just + + + align:start position:0% +be slightly below below forward just +because of discounting okay so and here + + align:start position:0% +because of discounting okay so and here + + + align:start position:0% +because of discounting okay so and here +here are a few three main points which + + align:start position:0% +here are a few three main points which + + + align:start position:0% +here are a few three main points which +we which will try to fall through the + + align:start position:0% +we which will try to fall through the + + + align:start position:0% +we which will try to fall through the +class so first of all what we'll see + + align:start position:0% +class so first of all what we'll see + + + align:start position:0% +class so first of all what we'll see +that if we we have current price of the + + align:start position:0% +that if we we have current price of the + + + align:start position:0% +that if we we have current price of the +underlying and some assumptions on the + + align:start position:0% +underlying and some assumptions on the + + + align:start position:0% +underlying and some assumptions on the +on how the the market or the the + + align:start position:0% +on how the the market or the the + + + align:start position:0% +on how the the market or the the +underlying behaves there is actually no + + align:start position:0% +underlying behaves there is actually no + + + align:start position:0% +underlying behaves there is actually no +uncertainty in the price of the option + + align:start position:0% +uncertainty in the price of the option + + + align:start position:0% +uncertainty in the price of the option +obviously if we if we fix the payout + + align:start position:0% +obviously if we if we fix the payout + + + align:start position:0% +obviously if we if we fix the payout +right so somehow there is no uncertainty + + align:start position:0% +right so somehow there is no uncertainty + + + align:start position:0% +right so somehow there is no uncertainty +it's completely deterministic once once + + align:start position:0% +it's completely deterministic once once + + + align:start position:0% +it's completely deterministic once once +we have once we know the price of + + align:start position:0% +we have once we know the price of + + + align:start position:0% +we have once we know the price of +underline the other + + align:start position:0% + + + + align:start position:0% + +interesting fact which we'll find out + + align:start position:0% +interesting fact which we'll find out + + + align:start position:0% +interesting fact which we'll find out +it's actually risk neutrality meaning + + align:start position:0% +it's actually risk neutrality meaning + + + align:start position:0% +it's actually risk neutrality meaning +that in fact the price of the option has + + align:start position:0% +that in fact the price of the option has + + + align:start position:0% +that in fact the price of the option has +nothing to do with the with the risk + + align:start position:0% +nothing to do with the with the risk + + + align:start position:0% +nothing to do with the with the risk +preferences of market participants or or + + align:start position:0% +preferences of market participants or or + + + align:start position:0% +preferences of market participants or or +or counterparties it's actually only + + align:start position:0% +or counterparties it's actually only + + + align:start position:0% +or counterparties it's actually only +depends on the dynamics of the stock + + align:start position:0% +depends on the dynamics of the stock + + + align:start position:0% +depends on the dynamics of the stock +only depends on volatility of the stock + + align:start position:0% +only depends on volatility of the stock + + + align:start position:0% +only depends on volatility of the stock +and finally the most important idea of + + align:start position:0% +and finally the most important idea of + + + align:start position:0% +and finally the most important idea of +this class that mathematical apparatus + + align:start position:0% +this class that mathematical apparatus + + + align:start position:0% +this class that mathematical apparatus +allows you to to figure out how much + + align:start position:0% +allows you to to figure out how much + + + align:start position:0% +allows you to to figure out how much +this deterministic option price is now + + align:start position:0% + + + + align:start position:0% + +so let's consider a very simple example + + align:start position:0% + + + + align:start position:0% + +very simple market to period so suppose + + align:start position:0% +very simple market to period so suppose + + + align:start position:0% +very simple market to period so suppose +our time is discrete and we are one step + + align:start position:0% +our time is discrete and we are one step + + + align:start position:0% +our time is discrete and we are one step +before the maturity so right now our + + align:start position:0% +before the maturity so right now our + + + align:start position:0% +before the maturity so right now our +stock has price as zero and there is + + align:start position:0% +stock has price as zero and there is + + + align:start position:0% +stock has price as zero and there is +some derivative F zero + + align:start position:0% +some derivative F zero + + + align:start position:0% +some derivative F zero +with some payout we will consider a few + + align:start position:0% +with some payout we will consider a few + + + align:start position:0% +with some payout we will consider a few +of those right also will add to the mix + + align:start position:0% +of those right also will add to the mix + + + align:start position:0% +of those right also will add to the mix +some a bit of cash right risk with cash + + align:start position:0% +some a bit of cash right risk with cash + + + align:start position:0% +some a bit of cash right risk with cash +this some amount of risk with cash be + + align:start position:0% +this some amount of risk with cash be + + + align:start position:0% +this some amount of risk with cash be +zero and risk less meaning that it grows + + align:start position:0% +zero and risk less meaning that it grows + + + align:start position:0% +zero and risk less meaning that it grows +exponentially with some interest rate R + + align:start position:0% +exponentially with some interest rate R + + + align:start position:0% +exponentially with some interest rate R +and there is no uncertainty it's + + align:start position:0% +and there is no uncertainty it's + + + align:start position:0% +and there is no uncertainty it's +completely if you have now busy row we + + align:start position:0% +completely if you have now busy row we + + + align:start position:0% +completely if you have now busy row we +know then in time DT our B 0 will be 0 + + align:start position:0% +know then in time DT our B 0 will be 0 + + + align:start position:0% +know then in time DT our B 0 will be 0 +will will will grow exponentially it + + align:start position:0% +will will will grow exponentially it + + + align:start position:0% +will will will grow exponentially it +will become B e to the RT so a bond + + align:start position:0% +will become B e to the RT so a bond + + + align:start position:0% +will become B e to the RT so a bond +basically zero coupon one a money market + + align:start position:0% +basically zero coupon one a money market + + + align:start position:0% +basically zero coupon one a money market +account rather is its if you go to + + align:start position:0% +account rather is its if you go to + + + align:start position:0% +account rather is its if you go to +Cambridge Savings Bank put $1 in today + + align:start position:0% +Cambridge Savings Bank put $1 in today + + + align:start position:0% +Cambridge Savings Bank put $1 in today +then in a year you'll get $1 and + + align:start position:0% +then in a year you'll get $1 and + + + align:start position:0% +then in a year you'll get $1 and +basically nothing because interest rates + + align:start position:0% +basically nothing because interest rates + + + align:start position:0% +basically nothing because interest rates +are zero so in in time DT we will assume + + align:start position:0% +are zero so in in time DT we will assume + + + align:start position:0% +are zero so in in time DT we will assume +with some probability P our market can + + align:start position:0% +with some probability P our market can + + + align:start position:0% +with some probability P our market can +go to the state where stock becomes s1 + + align:start position:0% +go to the state where stock becomes s1 + + + align:start position:0% +go to the state where stock becomes s1 +the price of stock becomes s1 our bond + + align:start position:0% +the price of stock becomes s1 our bond + + + align:start position:0% +the price of stock becomes s1 our bond +grows exponentially not no uncertainty + + align:start position:0% +grows exponentially not no uncertainty + + + align:start position:0% +grows exponentially not no uncertainty +and our derivative becomes f1 or with + + align:start position:0% +and our derivative becomes f1 or with + + + align:start position:0% +and our derivative becomes f1 or with +probability 1 minus P only two states so + + align:start position:0% +probability 1 minus P only two states so + + + align:start position:0% +probability 1 minus P only two states so +our stock becomes s2 bond stays the same + + align:start position:0% +our stock becomes s2 bond stays the same + + + align:start position:0% +our stock becomes s2 bond stays the same +and the the derivative is some f2 so + + align:start position:0% +and the the derivative is some f2 so + + + align:start position:0% +and the the derivative is some f2 so +let's start with with our simple + + align:start position:0% +let's start with with our simple + + + align:start position:0% +let's start with with our simple +contract the forward contract so one can + + align:start position:0% +contract the forward contract so one can + + + align:start position:0% +contract the forward contract so one can +naively approach this problem trying to + + align:start position:0% +naively approach this problem trying to + + + align:start position:0% +naively approach this problem trying to +get the price of of the derivative using + + align:start position:0% +get the price of of the derivative using + + + align:start position:0% +get the price of of the derivative using +the real-world probabilities P and minus + + align:start position:0% +the real-world probabilities P and minus + + + align:start position:0% +the real-world probabilities P and minus +P 1 minus P right so we know that the + + align:start position:0% +P 1 minus P right so we know that the + + + align:start position:0% +P 1 minus P right so we know that the +payout is s minus K that's that's given + + align:start position:0% +payout is s minus K that's that's given + + + align:start position:0% +payout is s minus K that's that's given +so one would say that if we we know we + + align:start position:0% +so one would say that if we we know we + + + align:start position:0% +so one would say that if we we know we +are one step before the payout so let's + + align:start position:0% +are one step before the payout so let's + + + align:start position:0% +are one step before the payout so let's +just compute expected value of the + + align:start position:0% +just compute expected value of the + + + align:start position:0% +just compute expected value of the +payout using real real-world + + align:start position:0% +payout using real real-world + + + align:start position:0% +payout using real real-world +probabilities get this this value and + + align:start position:0% +probabilities get this this value and + + + align:start position:0% +probabilities get this this value and +actually what we are looking here is to + + align:start position:0% +actually what we are looking here is to + + + align:start position:0% +actually what we are looking here is to +set K such that the price now at time + + align:start position:0% +set K such that the price now at time + + + align:start position:0% +set K such that the price now at time +and T is zero that's usual convention so + + align:start position:0% +and T is zero that's usual convention so + + + align:start position:0% +and T is zero that's usual convention so +will then set cake to do this to this + + align:start position:0% +will then set cake to do this to this + + + align:start position:0% +will then set cake to do this to this +probability to do this to this number + + align:start position:0% +probability to do this to this number + + + align:start position:0% +probability to do this to this number +which depends on real-world probability + + align:start position:0% +which depends on real-world probability + + + align:start position:0% +which depends on real-world probability +and obviously depends on the stock price + + align:start position:0% +and obviously depends on the stock price + + + align:start position:0% +and obviously depends on the stock price +at expiry so but obviously we don't know + + align:start position:0% +at expiry so but obviously we don't know + + + align:start position:0% +at expiry so but obviously we don't know +real-world probabilities we can guess we + + align:start position:0% +real-world probabilities we can guess we + + + align:start position:0% +real-world probabilities we can guess we +can say audits the stock is as likely to + + align:start position:0% +can say audits the stock is as likely to + + + align:start position:0% +can say audits the stock is as likely to +go up then then down then then it's just + + align:start position:0% +go up then then down then then it's just + + + align:start position:0% +go up then then down then then it's just +an average of n n stock prices or + + align:start position:0% +an average of n n stock prices or + + + align:start position:0% +an average of n n stock prices or +something else but it's all hand wavy + + align:start position:0% +something else but it's all hand wavy + + + align:start position:0% +something else but it's all hand wavy +and actually we never will be red + + align:start position:0% +and actually we never will be red + + + align:start position:0% +and actually we never will be red +instead of doing this we're kind of + + align:start position:0% +instead of doing this we're kind of + + + align:start position:0% +instead of doing this we're kind of +following bookie example let's try to do + + align:start position:0% +following bookie example let's try to do + + + align:start position:0% +following bookie example let's try to do +something else let's think a little bit + + align:start position:0% +something else let's think a little bit + + + align:start position:0% +something else let's think a little bit +so we have a stock which is trading it + + align:start position:0% +so we have a stock which is trading it + + + align:start position:0% +so we have a stock which is trading it +at market now for the price as zero how + + align:start position:0% +at market now for the price as zero how + + + align:start position:0% +at market now for the price as zero how +about we go to the bank and borrow as + + align:start position:0% +about we go to the bank and borrow as + + + align:start position:0% +about we go to the bank and borrow as +zero dollars right now and immediately + + align:start position:0% +zero dollars right now and immediately + + + align:start position:0% +zero dollars right now and immediately +go to the market and buy the stock so + + align:start position:0% +go to the market and buy the stock so + + + align:start position:0% +go to the market and buy the stock so +right now we are not net zero we + + align:start position:0% +right now we are not net zero we + + + align:start position:0% +right now we are not net zero we +borrowed as zero we paid it immediately + + align:start position:0% +borrowed as zero we paid it immediately + + + align:start position:0% +borrowed as zero we paid it immediately +to buy the stock so we have stock at + + align:start position:0% +to buy the stock so we have stock at + + + align:start position:0% +to buy the stock so we have stock at +hand then we'll wait for one period and + + align:start position:0% +hand then we'll wait for one period and + + + align:start position:0% +hand then we'll wait for one period and +and at the same time sorry we are we + + align:start position:0% +and at the same time sorry we are we + + + align:start position:0% +and at the same time sorry we are we +short we enter on the short side of the + + align:start position:0% +short we enter on the short side of the + + + align:start position:0% +short we enter on the short side of the +forward contract so we agree to sell the + + align:start position:0% +forward contract so we agree to sell the + + + align:start position:0% +forward contract so we agree to sell the +stock for for some price k zero so in DT + + align:start position:0% +stock for for some price k zero so in DT + + + align:start position:0% +stock for for some price k zero so in DT +in one period of time the the contrary + + align:start position:0% +in one period of time the the contrary + + + align:start position:0% +in one period of time the the contrary +expires we already have stock so we just + + align:start position:0% +expires we already have stock so we just + + + align:start position:0% +expires we already have stock so we just +go and exchange it for k 0 k zero + + align:start position:0% +go and exchange it for k 0 k zero + + + align:start position:0% +go and exchange it for k 0 k zero +dollars right but we at the same time we + + align:start position:0% +dollars right but we at the same time we + + + align:start position:0% +dollars right but we at the same time we +need to repay our loan which now have + + align:start position:0% +need to repay our loan which now have + + + align:start position:0% +need to repay our loan which now have +become as zero times e to the R DT this + + align:start position:0% +become as zero times e to the R DT this + + + align:start position:0% +become as zero times e to the R DT this +is deterministic right we borrowed a + + align:start position:0% +is deterministic right we borrowed a + + + align:start position:0% +is deterministic right we borrowed a +zero in time DT it became s times e to + + align:start position:0% +zero in time DT it became s times e to + + + align:start position:0% +zero in time DT it became s times e to +the R DT so what what's our net then + + align:start position:0% +the R DT so what what's our net then + + + align:start position:0% +the R DT so what what's our net then +that is K 0 minus s to the S + + align:start position:0% +that is K 0 minus s to the S + + + align:start position:0% +that is K 0 minus s to the S +times e R DT so suppose K 0 is greater + + align:start position:0% +times e R DT so suppose K 0 is greater + + + align:start position:0% +times e R DT so suppose K 0 is greater +than than this value then we made + + align:start position:0% +than than this value then we made + + + align:start position:0% +than than this value then we made +riskless profit that there is no risk in + + align:start position:0% +riskless profit that there is no risk in + + + align:start position:0% +riskless profit that there is no risk in +the in this in the strategy which we + + align:start position:0% +the in this in the strategy which we + + + align:start position:0% +the in this in the strategy which we +which we proposed so this is good but + + align:start position:0% +which we proposed so this is good but + + + align:start position:0% +which we proposed so this is good but +why wouldn't everybody do it all day + + align:start position:0% +why wouldn't everybody do it all day + + + align:start position:0% +why wouldn't everybody do it all day +long on the other hand if K 0 is less + + align:start position:0% +long on the other hand if K 0 is less + + + align:start position:0% +long on the other hand if K 0 is less +than s 0 that's that's that's a loss for + + align:start position:0% +than s 0 that's that's that's a loss for + + + align:start position:0% +than s 0 that's that's that's a loss for +sure and if anybody thinks as we did and + + align:start position:0% +sure and if anybody thinks as we did and + + + align:start position:0% +sure and if anybody thinks as we did and +we assume that everybody can do it and + + align:start position:0% +we assume that everybody can do it and + + + align:start position:0% +we assume that everybody can do it and +nobody would would want to enter it + + align:start position:0% +nobody would would want to enter it + + + align:start position:0% +nobody would would want to enter it +which means that in order for for our + + align:start position:0% +which means that in order for for our + + + align:start position:0% +which means that in order for for our +forward to pry it to be price 0 now the + + align:start position:0% +forward to pry it to be price 0 now the + + + align:start position:0% +forward to pry it to be price 0 now the +price the strike price has to be equal + + align:start position:0% +price the strike price has to be equal + + + align:start position:0% +price the strike price has to be equal +to 2 to this amount and there is no + + align:start position:0% +to 2 to this amount and there is no + + + align:start position:0% +to 2 to this amount and there is no +uncertainty about it so let's stop and + + align:start position:0% +uncertainty about it so let's stop and + + + align:start position:0% +uncertainty about it so let's stop and +think a little bit + + align:start position:0% +think a little bit + + + align:start position:0% +think a little bit +well actually just just to see just to + + align:start position:0% +well actually just just to see just to + + + align:start position:0% +well actually just just to see just to +see how it works and that's that's + + align:start position:0% +see how it works and that's that's + + + align:start position:0% +see how it works and that's that's +exactly why why why I set this this gate + + align:start position:0% +exactly why why why I set this this gate + + + align:start position:0% +exactly why why why I set this this gate +to this number so by the way who can + + align:start position:0% +to this number so by the way who can + + + align:start position:0% +to this number so by the way who can +tell me what which interest rate does it + + align:start position:0% +tell me what which interest rate does it + + + align:start position:0% +tell me what which interest rate does it +doesn't imply + + align:start position:0% + + + + align:start position:0% + +if our strike is our stock prices 80 our + + align:start position:0% +if our strike is our stock prices 80 our + + + align:start position:0% +if our strike is our stock prices 80 our +strike is eighty eight point four to one + + align:start position:0% +strike is eighty eight point four to one + + + align:start position:0% +strike is eighty eight point four to one +and and the expires in two years + + align:start position:0% + + + + align:start position:0% + +approximately two point five so in two + + align:start position:0% +approximately two point five so in two + + + align:start position:0% +approximately two point five so in two +years it will be five percent so roughly + + align:start position:0% +years it will be five percent so roughly + + + align:start position:0% +years it will be five percent so roughly +speaking without compounding it should + + align:start position:0% +speaking without compounding it should + + + align:start position:0% +speaking without compounding it should +be five percent of eighty plus five + + align:start position:0% +be five percent of eighty plus five + + + align:start position:0% +be five percent of eighty plus five +percent it would be eighty four so ten + + align:start position:0% +percent it would be eighty four so ten + + + align:start position:0% +percent it would be eighty four so ten +percent for two years so the interest + + align:start position:0% +percent for two years so the interest + + + align:start position:0% +percent for two years so the interest +rate is five five percent yet so yet + + align:start position:0% +rate is five five percent yet so yet + + + align:start position:0% +rate is five five percent yet so yet +it's actually exactly five with least + + align:start position:0% +it's actually exactly five with least + + + align:start position:0% +it's actually exactly five with least +compatible exponential component yeah + + align:start position:0% +compatible exponential component yeah + + + align:start position:0% +compatible exponential component yeah +well so good world probably five years + + align:start position:0% +well so good world probably five years + + + align:start position:0% +well so good world probably five years +ago that's how it would work the two + + align:start position:0% +ago that's how it would work the two + + + align:start position:0% +ago that's how it would work the two +years interest rates now the last time I + + align:start position:0% +years interest rates now the last time I + + + align:start position:0% +years interest rates now the last time I +checked was I think 30 bits we can check + + align:start position:0% +checked was I think 30 bits we can check + + + align:start position:0% +checked was I think 30 bits we can check +where where is the bond is trading now + + align:start position:0% + + + + align:start position:0% + +give me a sec + + align:start position:0% + + + + align:start position:0% + +yep 32 and a half basis points 1 11.6 + + align:start position:0% +yep 32 and a half basis points 1 11.6 + + + align:start position:0% +yep 32 and a half basis points 1 11.6 +basis points up since the morning quite + + align:start position:0% +basis points up since the morning quite + + + align:start position:0% +basis points up since the morning quite +a bit by the way so yeah so right now + + align:start position:0% +a bit by the way so yeah so right now + + + align:start position:0% +a bit by the way so yeah so right now +interest rates are basically zero so + + align:start position:0% +interest rates are basically zero so + + + align:start position:0% +interest rates are basically zero so +these two these two lines would be very + + align:start position:0% +these two these two lines would be very + + + align:start position:0% +these two these two lines would be very +close right now in for two years in any + + align:start position:0% +close right now in for two years in any + + + align:start position:0% +close right now in for two years in any +case so coming back to our to our + + align:start position:0% +case so coming back to our to our + + + align:start position:0% +case so coming back to our to our +example so what's what's important here + + align:start position:0% +example so what's what's important here + + + align:start position:0% +example so what's what's important here +how did we arrive to to to the stripe + + align:start position:0% +how did we arrive to to to the stripe + + + align:start position:0% +how did we arrive to to to the stripe +resort to this price of the forward + + align:start position:0% +resort to this price of the forward + + + align:start position:0% +resort to this price of the forward +contract we in fact tried + + align:start position:0% +contract we in fact tried + + + align:start position:0% +contract we in fact tried +we took some some amount of stock in + + align:start position:0% +we took some some amount of stock in + + + align:start position:0% +we took some some amount of stock in +this particular case it will be the + + align:start position:0% +this particular case it will be the + + + align:start position:0% +this particular case it will be the +words the whole price of stock + + align:start position:0% +words the whole price of stock + + + align:start position:0% +words the whole price of stock +we took some amount of cash and by + + align:start position:0% +we took some amount of cash and by + + + align:start position:0% +we took some amount of cash and by +combining these two pieces we somehow + + align:start position:0% +combining these two pieces we somehow + + + align:start position:0% +combining these two pieces we somehow +replicated the final payoff right and + + align:start position:0% +replicated the final payoff right and + + + align:start position:0% +replicated the final payoff right and +that's the general idea of risk-neutral + + align:start position:0% +that's the general idea of risk-neutral + + + align:start position:0% +that's the general idea of risk-neutral +pricing pricing and replicating + + align:start position:0% +pricing pricing and replicating + + + align:start position:0% +pricing pricing and replicating +portfolio what we will try to do in the + + align:start position:0% +portfolio what we will try to do in the + + + align:start position:0% +portfolio what we will try to do in the +rest of the class is for take a payoff + + align:start position:0% +rest of the class is for take a payoff + + + align:start position:0% +rest of the class is for take a payoff +and try to find a replicating portfolio + + align:start position:0% +and try to find a replicating portfolio + + + align:start position:0% +and try to find a replicating portfolio +may be more complicated maybe than a + + align:start position:0% +may be more complicated maybe than a + + + align:start position:0% +may be more complicated maybe than a +dynamic dynamic such that at the end + + align:start position:0% +dynamic dynamic such that at the end + + + align:start position:0% +dynamic dynamic such that at the end +this replicating portfolio will be + + align:start position:0% +this replicating portfolio will be + + + align:start position:0% +this replicating portfolio will be +exactly our payoff right and what would + + align:start position:0% +exactly our payoff right and what would + + + align:start position:0% +exactly our payoff right and what would +it mean obviously it would mean that the + + align:start position:0% +it mean obviously it would mean that the + + + align:start position:0% +it mean obviously it would mean that the +current the the current price of the + + align:start position:0% +current the the current price of the + + + align:start position:0% +current the the current price of the +derivative should be the price of our + + align:start position:0% +derivative should be the price of our + + + align:start position:0% +derivative should be the price of our +replicating portfolio right now right + + align:start position:0% +replicating portfolio right now right + + + align:start position:0% +replicating portfolio right now right +and that's how the the risk-neutral + + align:start position:0% +and that's how the the risk-neutral + + + align:start position:0% +and that's how the the risk-neutral +pricing works so we are still in this + + align:start position:0% +pricing works so we are still in this + + + align:start position:0% +pricing works so we are still in this +simple situation but we will try to + + align:start position:0% +simple situation but we will try to + + + align:start position:0% +simple situation but we will try to +price a general pay payoff f1 a general + + align:start position:0% +price a general pay payoff f1 a general + + + align:start position:0% +price a general pay payoff f1 a general +payoff F right and here I how how it + + align:start position:0% +payoff F right and here I how how it + + + align:start position:0% +payoff F right and here I how how it +goes so we still will try to form our + + align:start position:0% +goes so we still will try to form our + + + align:start position:0% +goes so we still will try to form our +replicating portfolio out of the bond of + + align:start position:0% +replicating portfolio out of the bond of + + + align:start position:0% +replicating portfolio out of the bond of +some amount of bond and some amount of + + align:start position:0% +some amount of bond and some amount of + + + align:start position:0% +some amount of bond and some amount of +stock and we will say that will we will + + align:start position:0% +stock and we will say that will we will + + + align:start position:0% +stock and we will say that will we will +need a s1 and B of the bond right and we + + align:start position:0% +need a s1 and B of the bond right and we + + + align:start position:0% +need a s1 and B of the bond right and we +try to we'll try to find a and B + + align:start position:0% +try to we'll try to find a and B + + + align:start position:0% +try to we'll try to find a and B +that no matter what the real-world + + align:start position:0% +that no matter what the real-world + + + align:start position:0% +that no matter what the real-world +probability is we at maturity at one + + align:start position:0% +probability is we at maturity at one + + + align:start position:0% +probability is we at maturity at one +step maturity will replicate our payoff + + align:start position:0% +step maturity will replicate our payoff + + + align:start position:0% +step maturity will replicate our payoff +exactly unfortunately in this particular + + align:start position:0% +exactly unfortunately in this particular + + + align:start position:0% +exactly unfortunately in this particular +case that's very doable is just two + + align:start position:0% +case that's very doable is just two + + + align:start position:0% +case that's very doable is just two +equations with two variables we should + + align:start position:0% +equations with two variables we should + + + align:start position:0% +equations with two variables we should +be able to do it and we can solve it and + + align:start position:0% +be able to do it and we can solve it and + + + align:start position:0% +be able to do it and we can solve it and +find this a and B then we'll substitute + + align:start position:0% +find this a and B then we'll substitute + + + align:start position:0% +find this a and B then we'll substitute +them in this formula right take the + + align:start position:0% +them in this formula right take the + + + align:start position:0% +them in this formula right take the +current price of the stock which we know + + align:start position:0% +current price of the stock which we know + + + align:start position:0% +current price of the stock which we know +and and some cash and find the current + + align:start position:0% +and and some cash and find the current + + + align:start position:0% +and and some cash and find the current +price current price of the derivative + + align:start position:0% +price current price of the derivative + + + align:start position:0% +price current price of the derivative +right and this work this should work for + + align:start position:0% +right and this work this should work for + + + align:start position:0% +right and this work this should work for +any derivatives it doesn't matter is it + + align:start position:0% +any derivatives it doesn't matter is it + + + align:start position:0% +any derivatives it doesn't matter is it +forward call put or some complicated + + align:start position:0% +forward call put or some complicated + + + align:start position:0% +forward call put or some complicated +complicated option as long as it's + + align:start position:0% +complicated option as long as it's + + + align:start position:0% +complicated option as long as it's +deterministic at expiry an interesting + + align:start position:0% +deterministic at expiry an interesting + + + align:start position:0% +deterministic at expiry an interesting +way to look at it is to rewrite this + + align:start position:0% +way to look at it is to rewrite this + + + align:start position:0% +way to look at it is to rewrite this +formula slightly in such a way which + + align:start position:0% +formula slightly in such a way which + + + align:start position:0% +formula slightly in such a way which +does remind us taking a an expected + + align:start position:0% +does remind us taking a an expected + + + align:start position:0% +does remind us taking a an expected +value may be discounting it because this + + align:start position:0% +value may be discounting it because this + + + align:start position:0% +value may be discounting it because this +is expected value sometime in the future + + align:start position:0% +is expected value sometime in the future + + + align:start position:0% +is expected value sometime in the future +but this probability and it is a + + align:start position:0% +but this probability and it is a + + + align:start position:0% +but this probability and it is a +probability because this number Q here + + align:start position:0% +probability because this number Q here + + + align:start position:0% +probability because this number Q here +is between 0 and 1 but this probability + + align:start position:0% +is between 0 and 1 but this probability + + + align:start position:0% +is between 0 and 1 but this probability +has little to do with with real real + + align:start position:0% +has little to do with with real real + + + align:start position:0% +has little to do with with real real +real world right in fact it's something + + align:start position:0% +real world right in fact it's something + + + align:start position:0% +real world right in fact it's something +different but such probabilities exists + + align:start position:0% +different but such probabilities exists + + + align:start position:0% +different but such probabilities exists +and it's called the measure where our + + align:start position:0% +and it's called the measure where our + + + align:start position:0% +and it's called the measure where our +stock behaves like this is called a + + align:start position:0% +stock behaves like this is called a + + + align:start position:0% +stock behaves like this is called a +risk-neutral measure or martingale mere + + align:start position:0% +risk-neutral measure or martingale mere + + + align:start position:0% +risk-neutral measure or martingale mere +measure and in these measures will see + + align:start position:0% +measure and in these measures will see + + + align:start position:0% +measure and in these measures will see +the the value of all the derivative will + + align:start position:0% +the the value of all the derivative will + + + align:start position:0% +the the value of all the derivative will +be just expected value of our appeal and + + align:start position:0% +be just expected value of our appeal and + + + align:start position:0% +be just expected value of our appeal and +that's yeah that's what what I'm trying + + align:start position:0% +that's yeah that's what what I'm trying + + + align:start position:0% +that's yeah that's what what I'm trying +to say here + + align:start position:0% + + + + align:start position:0% + +now so now let's get into continuous + + align:start position:0% +now so now let's get into continuous + + + align:start position:0% +now so now let's get into continuous +world right in continuous world we will + + align:start position:0% +world right in continuous world we will + + + align:start position:0% +world right in continuous world we will +need some assumptions on the dynamics of + + align:start position:0% +need some assumptions on the dynamics of + + + align:start position:0% +need some assumptions on the dynamics of +our stock underline and let's make an + + align:start position:0% +our stock underline and let's make an + + + align:start position:0% +our stock underline and let's make an +assumption that it is law it it is log + + align:start position:0% +assumption that it is law it it is log + + + align:start position:0% +assumption that it is law it it is log +normal what it what does it mean that + + align:start position:0% +normal what it what does it mean that + + + align:start position:0% +normal what it what does it mean that +it's look more normal it means that the + + align:start position:0% +it's look more normal it means that the + + + align:start position:0% +it's look more normal it means that the +proportional change of the stock over + + align:start position:0% +proportional change of the stock over + + + align:start position:0% +proportional change of the stock over +infants infinitely small amount of time + + align:start position:0% +infants infinitely small amount of time + + + align:start position:0% +infants infinitely small amount of time +DT has some drift mu and some stochastic + + align:start position:0% +DT has some drift mu and some stochastic + + + align:start position:0% +DT has some drift mu and some stochastic +component which is just Brownian motion + + align:start position:0% +component which is just Brownian motion + + + align:start position:0% +component which is just Brownian motion +right so this DW is distributed normally + + align:start position:0% +right so this DW is distributed normally + + + align:start position:0% +right so this DW is distributed normally +with mean zero and start the deviation + + align:start position:0% +with mean zero and start the deviation + + + align:start position:0% +with mean zero and start the deviation +which is actually square root of DT + + align:start position:0% +which is actually square root of DT + + + align:start position:0% +which is actually square root of DT +that's how broadly emotion works and + + align:start position:0% +that's how broadly emotion works and + + + align:start position:0% +that's how broadly emotion works and +that's extremely important that the + + align:start position:0% +that's extremely important that the + + + align:start position:0% +that's extremely important that the +standard deviation of going Brownian + + align:start position:0% +standard deviation of going Brownian + + + align:start position:0% +standard deviation of going Brownian +motion is square root of delta T and + + align:start position:0% +motion is square root of delta T and + + + align:start position:0% +motion is square root of delta T and +that's how it works so and again we will + + align:start position:0% +that's how it works so and again we will + + + align:start position:0% +that's how it works so and again we will +use this idea of replicating portfolio + + align:start position:0% +use this idea of replicating portfolio + + + align:start position:0% +use this idea of replicating portfolio +what would it mean in this in this case + + align:start position:0% +what would it mean in this in this case + + + align:start position:0% +what would it mean in this in this case +well we will we would like to find such + + align:start position:0% +well we will we would like to find such + + + align:start position:0% +well we will we would like to find such +coefficients a and B on this infinitely + + align:start position:0% +coefficients a and B on this infinitely + + + align:start position:0% +coefficients a and B on this infinitely +small period of time DT such that by + + align:start position:0% +small period of time DT such that by + + + align:start position:0% +small period of time DT such that by +combining small changes in stock with + + align:start position:0% +combining small changes in stock with + + + align:start position:0% +combining small changes in stock with +coefficient a and small changes in in + + align:start position:0% +coefficient a and small changes in in + + + align:start position:0% +coefficient a and small changes in in +bond with with coefficient B will + + align:start position:0% +bond with with coefficient B will + + + align:start position:0% +bond with with coefficient B will +exactly replicate the change in the + + align:start position:0% +exactly replicate the change in the + + + align:start position:0% +exactly replicate the change in the +derivative in the payout of derivative + + align:start position:0% +derivative in the payout of derivative + + + align:start position:0% +derivative in the payout of derivative +in indeed not PL in the derivative in + + align:start position:0% +in indeed not PL in the derivative in + + + align:start position:0% +in indeed not PL in the derivative in +the change of the derivative over this + + align:start position:0% +the change of the derivative over this + + + align:start position:0% +the change of the derivative over this +infinitely small time T well to do this + + align:start position:0% +infinitely small time T well to do this + + + align:start position:0% +infinitely small time T well to do this +we will need to use it as formula did + + align:start position:0% +we will need to use it as formula did + + + align:start position:0% +we will need to use it as formula did +you talk about either already ok cool + + align:start position:0% +you talk about either already ok cool + + + align:start position:0% +you talk about either already ok cool +that's great + + align:start position:0% +that's great + + + align:start position:0% +that's great +so just to remind you that it is formula + + align:start position:0% +so just to remind you that it is formula + + + align:start position:0% +so just to remind you that it is formula +is nothing more than the Taylor rule + + align:start position:0% +is nothing more than the Taylor rule + + + align:start position:0% +is nothing more than the Taylor rule +the first approximation up to DT but + + align:start position:0% +the first approximation up to DT but + + + align:start position:0% +the first approximation up to DT but +because of of the standard deviation of + + align:start position:0% +because of of the standard deviation of + + + align:start position:0% +because of of the standard deviation of +the Brownian motion being on on the + + align:start position:0% +the Brownian motion being on on the + + + align:start position:0% +the Brownian motion being on on the +scale of square root of T we will need + + align:start position:0% +scale of square root of T we will need + + + align:start position:0% +scale of square root of T we will need +one more term right so one one term is + + align:start position:0% +one more term right so one one term is + + + align:start position:0% +one more term right so one one term is +DF DT by DT another is DF by D as well + + align:start position:0% +DF DT by DT another is DF by D as well + + + align:start position:0% +DF DT by DT another is DF by D as well +yes but and the square of GS now is is + + align:start position:0% +yes but and the square of GS now is is + + + align:start position:0% +yes but and the square of GS now is is +actually of order of magnitude of DT so + + align:start position:0% +actually of order of magnitude of DT so + + + align:start position:0% +actually of order of magnitude of DT so +we'll need a quadratic term there all + + align:start position:0% +we'll need a quadratic term there all + + + align:start position:0% +we'll need a quadratic term there all +right so if this is our DF so what we'll + + align:start position:0% +right so if this is our DF so what we'll + + + align:start position:0% +right so if this is our DF so what we'll +do we'll differentiate we will just + + align:start position:0% +do we'll differentiate we will just + + + align:start position:0% +do we'll differentiate we will just +substitute it here right we'll + + align:start position:0% +substitute it here right we'll + + + align:start position:0% +substitute it here right we'll +substitute it here we'll substitute DF + + align:start position:0% +substitute it here we'll substitute DF + + + align:start position:0% +substitute it here we'll substitute DF +taken from it as our D s each which is + + align:start position:0% +taken from it as our D s each which is + + + align:start position:0% +taken from it as our D s each which is +like this N and G B and D B is let's not + + align:start position:0% +like this N and G B and D B is let's not + + + align:start position:0% +like this N and G B and D B is let's not +forget that DB that B is deterministic + + align:start position:0% +forget that DB that B is deterministic + + + align:start position:0% +forget that DB that B is deterministic +right there is nothing uncertain about + + align:start position:0% +right there is nothing uncertain about + + + align:start position:0% +right there is nothing uncertain about +it so DB is actual RB DT right because + + align:start position:0% +it so DB is actual RB DT right because + + + align:start position:0% +it so DB is actual RB DT right because +our B grows exponentially with interest + + align:start position:0% +our B grows exponentially with interest + + + align:start position:0% +our B grows exponentially with interest +rate R so we substitute everything into + + align:start position:0% +rate R so we substitute everything into + + + align:start position:0% +rate R so we substitute everything into +the formula above this is just our DF + + align:start position:0% +the formula above this is just our DF + + + align:start position:0% +the formula above this is just our DF +with D as expanded and everything and + + align:start position:0% +with D as expanded and everything and + + + align:start position:0% +with D as expanded and everything and +then we start compare comparing the + + align:start position:0% +then we start compare comparing the + + + align:start position:0% +then we start compare comparing the +terms one immediate thing to notice that + + align:start position:0% +terms one immediate thing to notice that + + + align:start position:0% +terms one immediate thing to notice that +a has to be equal to G of D F for over D + + align:start position:0% +a has to be equal to G of D F for over D + + + align:start position:0% +a has to be equal to G of D F for over D +s for this for this to hold right and if + + align:start position:0% +s for this for this to hold right and if + + + align:start position:0% +s for this for this to hold right and if +we compare the the terms you know DT + + align:start position:0% +we compare the the terms you know DT + + + align:start position:0% +we compare the the terms you know DT +will get this expression here but that's + + align:start position:0% +will get this expression here but that's + + + align:start position:0% +will get this expression here but that's +actually even more the most important + + align:start position:0% +actually even more the most important + + + align:start position:0% +actually even more the most important +part then we'll we'll go and use the our + + align:start position:0% +part then we'll we'll go and use the our + + + align:start position:0% +part then we'll we'll go and use the our +knowledge that that some part of our + + align:start position:0% +knowledge that that some part of our + + + align:start position:0% +knowledge that that some part of our +equation is deterministic and basically + + align:start position:0% +equation is deterministic and basically + + + align:start position:0% +equation is deterministic and basically +take F and a s on one side and leave the + + align:start position:0% +take F and a s on one side and leave the + + + align:start position:0% +take F and a s on one side and leave the +deterministic part on the other side + + align:start position:0% +deterministic part on the other side + + + align:start position:0% +deterministic part on the other side +differentiate differentiate it once once + + align:start position:0% +differentiate differentiate it once once + + + align:start position:0% +differentiate differentiate it once once +again and left left side will be just RB + + align:start position:0% +again and left left side will be just RB + + + align:start position:0% +again and left left side will be just RB +DT and if we substitute once again d DF + + align:start position:0% +DT and if we substitute once again d DF + + + align:start position:0% +DT and if we substitute once again d DF +and don't forget that what we learned is + + align:start position:0% +and don't forget that what we learned is + + + align:start position:0% +and don't forget that what we learned is +that a is equal to DF by D s then we + + align:start position:0% +that a is equal to DF by D s then we + + + align:start position:0% +that a is equal to DF by D s then we +collect all the terms and arrive to this + + align:start position:0% +collect all the terms and arrive to this + + + align:start position:0% +collect all the terms and arrive to this +to this partial differential equation + + align:start position:0% +to this partial differential equation + + + align:start position:0% +to this partial differential equation +which which connects which basically is + + align:start position:0% +which which connects which basically is + + + align:start position:0% +which which connects which basically is +a partial differential equation for the + + align:start position:0% +a partial differential equation for the + + + align:start position:0% +a partial differential equation for the +current price of a derivative of any + + align:start position:0% +current price of a derivative of any + + + align:start position:0% +current price of a derivative of any +derivative and how it if we solve it + + align:start position:0% +derivative and how it if we solve it + + + align:start position:0% +derivative and how it if we solve it +then way we should should be able to to + + align:start position:0% +then way we should should be able to to + + + align:start position:0% +then way we should should be able to to +know the price of the order derivative + + align:start position:0% +know the price of the order derivative + + + align:start position:0% +know the price of the order derivative +so now how do we solve this this partial + + align:start position:0% +so now how do we solve this this partial + + + align:start position:0% +so now how do we solve this this partial +differential equation well yeah so a few + + align:start position:0% +differential equation well yeah so a few + + + align:start position:0% +differential equation well yeah so a few +observations about about this equation + + align:start position:0% +observations about about this equation + + + align:start position:0% +observations about about this equation +well the the first observation is that + + align:start position:0% +well the the first observation is that + + + align:start position:0% +well the the first observation is that +any tradable derivative we made no + + align:start position:0% +any tradable derivative we made no + + + align:start position:0% +any tradable derivative we made no +assumptions about the payoff so so any + + align:start position:0% +assumptions about the payoff so so any + + + align:start position:0% +assumptions about the payoff so so any +tradable derivative is any payoff should + + align:start position:0% +tradable derivative is any payoff should + + + align:start position:0% +tradable derivative is any payoff should +satisfy this equation the other + + align:start position:0% +satisfy this equation the other + + + align:start position:0% +satisfy this equation the other +observation is as we expected there is + + align:start position:0% +observation is as we expected there is + + + align:start position:0% +observation is as we expected there is +no dependency on real-world drift or any + + align:start position:0% +no dependency on real-world drift or any + + + align:start position:0% +no dependency on real-world drift or any +any probabilities of going up or down + + align:start position:0% +any probabilities of going up or down + + + align:start position:0% +any probabilities of going up or down +the only dependence dependence is on the + + align:start position:0% +the only dependence dependence is on the + + + align:start position:0% +the only dependence dependence is on the +volatility of the stock right not only + + align:start position:0% +volatility of the stock right not only + + + align:start position:0% +volatility of the stock right not only +we we found the value of the derivative + + align:start position:0% +we we found the value of the derivative + + + align:start position:0% +we we found the value of the derivative +so most importantly we actually we're + + align:start position:0% +so most importantly we actually we're + + + align:start position:0% +so most importantly we actually we're +able to come up with with a hedging + + align:start position:0% +able to come up with with a hedging + + + align:start position:0% +able to come up with with a hedging +strategy and what does it mean we came + + align:start position:0% +strategy and what does it mean we came + + + align:start position:0% +strategy and what does it mean we came +up with a hedging strategy + + align:start position:0% +up with a hedging strategy + + + align:start position:0% +up with a hedging strategy +well we found coefficients for any time + + align:start position:0% +well we found coefficients for any time + + + align:start position:0% +well we found coefficients for any time +we found the coefficients a and B such + + align:start position:0% +we found the coefficients a and B such + + + align:start position:0% +we found the coefficients a and B such +that we have a replicating portfolio so + + align:start position:0% +that we have a replicating portfolio so + + + align:start position:0% +that we have a replicating portfolio so +instead what we could do at any point of + + align:start position:0% +instead what we could do at any point of + + + align:start position:0% +instead what we could do at any point of +time we can hold the derivative the + + align:start position:0% +time we can hold the derivative the + + + align:start position:0% +time we can hold the derivative the +short a show derivative and long the + + align:start position:0% +short a show derivative and long the + + + align:start position:0% +short a show derivative and long the +portfolio of stock itself and some cash + + align:start position:0% +portfolio of stock itself and some cash + + + align:start position:0% +portfolio of stock itself and some cash +and we know how much it should be + + align:start position:0% +and we know how much it should be + + + align:start position:0% +and we know how much it should be +here it's more complicated we have to + + align:start position:0% +here it's more complicated we have to + + + align:start position:0% +here it's more complicated we have to +dynamically change these numbers as time + + align:start position:0% +dynamically change these numbers as time + + + align:start position:0% +dynamically change these numbers as time +develops every time DT we will have to + + align:start position:0% +develops every time DT we will have to + + + align:start position:0% +develops every time DT we will have to +rebound but both both parts will + + align:start position:0% +rebound but both both parts will + + + align:start position:0% +rebound but both both parts will +replicate each other perfectly + + align:start position:0% +replicate each other perfectly + + + align:start position:0% +replicate each other perfectly +it's like in a bookies example we can go + + align:start position:0% +it's like in a bookies example we can go + + + align:start position:0% +it's like in a bookies example we can go +go to a two counterparty I agree into + + align:start position:0% +go to a two counterparty I agree into + + + align:start position:0% +go to a two counterparty I agree into +four for some derivative contract + + align:start position:0% +four for some derivative contract + + + align:start position:0% +four for some derivative contract +probably with some fee and then we will + + align:start position:0% +probably with some fee and then we will + + + align:start position:0% +probably with some fee and then we will +go to exchange and buy the stock and and + + align:start position:0% +go to exchange and buy the stock and and + + + align:start position:0% +go to exchange and buy the stock and and +we will get just cash from the bank and + + align:start position:0% +we will get just cash from the bank and + + + align:start position:0% +we will get just cash from the bank and +we'll maintain this at some amount of + + align:start position:0% +we'll maintain this at some amount of + + + align:start position:0% +we'll maintain this at some amount of +talk and some amount of cash and we will + + align:start position:0% +talk and some amount of cash and we will + + + align:start position:0% +talk and some amount of cash and we will +be sure that we are we are hedged there + + align:start position:0% +be sure that we are we are hedged there + + + align:start position:0% +be sure that we are we are hedged there +is no risk in in this color combination + + align:start position:0% +is no risk in in this color combination + + + align:start position:0% +is no risk in in this color combination +of the derivative and in our hedge so we + + align:start position:0% +of the derivative and in our hedge so we + + + align:start position:0% +of the derivative and in our hedge so we +will just collect the fee on the + + align:start position:0% +will just collect the fee on the + + + align:start position:0% +will just collect the fee on the +transaction so that's that's what + + align:start position:0% +transaction so that's that's what + + + align:start position:0% +transaction so that's that's what +actually how the business is working we + + align:start position:0% +actually how the business is working we + + + align:start position:0% +actually how the business is working we +traders are trading and hedging their + + align:start position:0% +traders are trading and hedging their + + + align:start position:0% +traders are trading and hedging their +positions immediately I mean they do + + align:start position:0% +positions immediately I mean they do + + + align:start position:0% +positions immediately I mean they do +take some market risks but you want to + + align:start position:0% +take some market risks but you want to + + + align:start position:0% +take some market risks but you want to +take very very little and very + + align:start position:0% +take very very little and very + + + align:start position:0% +take very very little and very +directional or very specific market risk + + align:start position:0% +directional or very specific market risk + + + align:start position:0% +directional or very specific market risk +and not not everything so so the the our + + align:start position:0% +and not not everything so so the the our + + + align:start position:0% +and not not everything so so the the our +strategy allows us to have a hedging + + align:start position:0% +strategy allows us to have a hedging + + + align:start position:0% +strategy allows us to have a hedging +portfolio at the same time hedging + + align:start position:0% +portfolio at the same time hedging + + + align:start position:0% +portfolio at the same time hedging +strategy another more mathematical but + + align:start position:0% +strategy another more mathematical but + + + align:start position:0% +strategy another more mathematical but +practical consequence is that actually + + align:start position:0% +practical consequence is that actually + + + align:start position:0% +practical consequence is that actually +by certain not very easy change of + + align:start position:0% +by certain not very easy change of + + + align:start position:0% +by certain not very easy change of +variables we can take the black Scholes + + align:start position:0% +variables we can take the black Scholes + + + align:start position:0% +variables we can take the black Scholes +equation and put it back to heat + + align:start position:0% +equation and put it back to heat + + + align:start position:0% +equation and put it back to heat +equation actually it's I suggest it as + + align:start position:0% +equation actually it's I suggest it as + + + align:start position:0% +equation actually it's I suggest it as +one of the topics for the final paper + + align:start position:0% +one of the topics for the final paper + + + align:start position:0% +one of the topics for the final paper +for you to do it or check it out in the + + align:start position:0% +for you to do it or check it out in the + + + align:start position:0% +for you to do it or check it out in the +books and go and understand it but the + + align:start position:0% +books and go and understand it but the + + + align:start position:0% +books and go and understand it but the +good part of it that heat equation is + + align:start position:0% +good part of it that heat equation is + + + align:start position:0% +good part of it that heat equation is +well known and well well understood + + align:start position:0% +well known and well well understood + + + align:start position:0% +well known and well well understood +there there are many many ways to solve + + align:start position:0% +there there are many many ways to solve + + + align:start position:0% +there there are many many ways to solve +it numerically for for simple payouts or + + align:start position:0% +it numerically for for simple payouts or + + + align:start position:0% +it numerically for for simple payouts or +for calls and puts we don't have to do + + align:start position:0% +for calls and puts we don't have to do + + + align:start position:0% +for calls and puts we don't have to do +it numerically but if the payout payoffs + + align:start position:0% +it numerically but if the payout payoffs + + + align:start position:0% +it numerically but if the payout payoffs +are more complicated or the the dynamics + + align:start position:0% +are more complicated or the the dynamics + + + align:start position:0% +are more complicated or the the dynamics +is is different then numerical methods + + align:start position:0% +is is different then numerical methods + + + align:start position:0% +is is different then numerical methods +will be needed for + + align:start position:0% +will be needed for + + + align:start position:0% +will be needed for +so again to solve this equation we'll + + align:start position:0% +so again to solve this equation we'll + + + align:start position:0% +so again to solve this equation we'll +need as for any partial differential + + align:start position:0% +need as for any partial differential + + + align:start position:0% +need as for any partial differential +equation we'll need some boundary and + + align:start position:0% +equation we'll need some boundary and + + + align:start position:0% +equation we'll need some boundary and +initial conditions and these come from + + align:start position:0% +initial conditions and these come from + + + align:start position:0% +initial conditions and these come from +our final payout fro of the option right + + align:start position:0% +our final payout fro of the option right + + + align:start position:0% +our final payout fro of the option right +which we know we know what what happens + + align:start position:0% +which we know we know what what happens + + + align:start position:0% +which we know we know what what happens +at expiry and some boundary conditions + + align:start position:0% +at expiry and some boundary conditions + + + align:start position:0% +at expiry and some boundary conditions +for for call and put the final payout is + + align:start position:0% +for for call and put the final payout is + + + align:start position:0% +for for call and put the final payout is +we know right + + align:start position:0% +we know right + + + align:start position:0% +we know right +so at time T and the boundary conditions + + align:start position:0% +so at time T and the boundary conditions + + + align:start position:0% +so at time T and the boundary conditions +which describe we discussed we can + + align:start position:0% +which describe we discussed we can + + + align:start position:0% +which describe we discussed we can +observe them graphically so basically + + align:start position:0% +observe them graphically so basically + + + align:start position:0% +observe them graphically so basically +for call as we said at current time T + + align:start position:0% +for call as we said at current time T + + + align:start position:0% +for call as we said at current time T +and boundary 0 it should be 0 the price + + align:start position:0% +and boundary 0 it should be 0 the price + + + align:start position:0% +and boundary 0 it should be 0 the price +should be 0 and at at infinity it should + + align:start position:0% +should be 0 and at at infinity it should + + + align:start position:0% +should be 0 and at at infinity it should +be actually the forward price so it + + align:start position:0% +be actually the forward price so it + + + align:start position:0% +be actually the forward price so it +should be just discounted discounted + + align:start position:0% +should be just discounted discounted + + + align:start position:0% +should be just discounted discounted +discounted s minus K discounted payout + + align:start position:0% +discounted s minus K discounted payout + + + align:start position:0% +discounted s minus K discounted payout +rate and similarly fought for put + + align:start position:0% + + + + align:start position:0% + +so given this these conditions and we we + + align:start position:0% +so given this these conditions and we we + + + align:start position:0% +so given this these conditions and we we +we can solve the equation and as I said + + align:start position:0% +we can solve the equation and as I said + + + align:start position:0% +we can solve the equation and as I said +for for : put and for simple dynamics or + + align:start position:0% +for for : put and for simple dynamics or + + + align:start position:0% +for for : put and for simple dynamics or +Blackshaw dynamic log normal dynamics + + align:start position:0% +Blackshaw dynamic log normal dynamics + + + align:start position:0% +Blackshaw dynamic log normal dynamics +actually these this equations can be + + align:start position:0% +actually these this equations can be + + + align:start position:0% +actually these this equations can be +solved exactly exactly + + align:start position:0% +solved exactly exactly + + + align:start position:0% +solved exactly exactly +meaning up to up to disturb the normal + + align:start position:0% +meaning up to up to disturb the normal + + + align:start position:0% +meaning up to up to disturb the normal +normal distribution which still has to + + align:start position:0% +normal distribution which still has to + + + align:start position:0% +normal distribution which still has to +be computed numerically obviously but + + align:start position:0% +be computed numerically obviously but + + + align:start position:0% +be computed numerically obviously but +here as a formulas they do kind of look + + align:start position:0% +here as a formulas they do kind of look + + + align:start position:0% +here as a formulas they do kind of look +a little bit and we'll see well about it + + align:start position:0% +a little bit and we'll see well about it + + + align:start position:0% +a little bit and we'll see well about it +that there is some kind of expected + + align:start position:0% +that there is some kind of expected + + + align:start position:0% +that there is some kind of expected +value blowing on right one probability + + align:start position:0% +value blowing on right one probability + + + align:start position:0% +value blowing on right one probability +times time times another but these are + + align:start position:0% +times time times another but these are + + + align:start position:0% +times time times another but these are +the formulas and that's how I drew the + + align:start position:0% +the formulas and that's how I drew the + + + align:start position:0% +the formulas and that's how I drew the +lines on the graphs and as I said in + + align:start position:0% +lines on the graphs and as I said in + + + align:start position:0% +lines on the graphs and as I said in +fact the whole world instead of solving + + align:start position:0% +fact the whole world instead of solving + + + align:start position:0% +fact the whole world instead of solving +the whole the whole partial differential + + align:start position:0% +the whole the whole partial differential + + + align:start position:0% +the whole the whole partial differential +equation we can approach it from a risk + + align:start position:0% +equation we can approach it from a risk + + + align:start position:0% +equation we can approach it from a risk +neutral risk neutral position and say + + align:start position:0% +neutral risk neutral position and say + + + align:start position:0% +neutral risk neutral position and say +that in fact the price of our derivative + + align:start position:0% +that in fact the price of our derivative + + + align:start position:0% +that in fact the price of our derivative +now is just as expected value of out pay + + align:start position:0% +now is just as expected value of out pay + + + align:start position:0% +now is just as expected value of out pay +or payout discounted probably from from + + align:start position:0% +or payout discounted probably from from + + + align:start position:0% +or payout discounted probably from from +the from the maturity but not in real + + align:start position:0% +the from the maturity but not in real + + + align:start position:0% +the from the maturity but not in real +time a real-world matter but in some + + align:start position:0% +time a real-world matter but in some + + + align:start position:0% +time a real-world matter but in some +specific risk-neutral measure and how + + align:start position:0% +specific risk-neutral measure and how + + + align:start position:0% +specific risk-neutral measure and how +how do you find this risk-neutral + + align:start position:0% +how do you find this risk-neutral + + + align:start position:0% +how do you find this risk-neutral +measure well the risk-neutral measure is + + align:start position:0% +measure well the risk-neutral measure is + + + align:start position:0% +measure well the risk-neutral measure is +such that the drift of our stock is + + align:start position:0% +such that the drift of our stock is + + + align:start position:0% +such that the drift of our stock is +actually interest rate its riskless + + align:start position:0% +actually interest rate its riskless + + + align:start position:0% +actually interest rate its riskless +that's exactly how how we saw we saw it + + align:start position:0% +that's exactly how how we saw we saw it + + + align:start position:0% +that's exactly how how we saw we saw it +we saw it in our binary example right so + + align:start position:0% +we saw it in our binary example right so + + + align:start position:0% +we saw it in our binary example right so +even in our binary example the our + + align:start position:0% +even in our binary example the our + + + align:start position:0% +even in our binary example the our +expected value of our stock under + + align:start position:0% +expected value of our stock under + + + align:start position:0% +expected value of our stock under +risk-neutral measure meaning + + align:start position:0% +risk-neutral measure meaning + + + align:start position:0% +risk-neutral measure meaning +using the risk-neutral probability was + + align:start position:0% +using the risk-neutral probability was + + + align:start position:0% +using the risk-neutral probability was +was drifting with this interest rate are + + align:start position:0% +was drifting with this interest rate are + + + align:start position:0% +was drifting with this interest rate are +so that the same happens in in + + align:start position:0% +so that the same happens in in + + + align:start position:0% +so that the same happens in in +continuous case and that's another good + + align:start position:0% +continuous case and that's another good + + + align:start position:0% +continuous case and that's another good +exercise and I would accept it as a + + align:start position:0% +exercise and I would accept it as a + + + align:start position:0% +exercise and I would accept it as a +final paper is computing black Scholes + + align:start position:0% +final paper is computing black Scholes + + + align:start position:0% +final paper is computing black Scholes +black Scholes driving the black Scholes + + align:start position:0% +black Scholes driving the black Scholes + + + align:start position:0% +black Scholes driving the black Scholes +formula just by discount by taking + + align:start position:0% +formula just by discount by taking + + + align:start position:0% +formula just by discount by taking +expected value of the Colin put payout + + align:start position:0% +expected value of the Colin put payout + + + align:start position:0% +expected value of the Colin put payout +with is the distribution log normal + + align:start position:0% +with is the distribution log normal + + + align:start position:0% +with is the distribution log normal +distribution terminal distribution + + align:start position:0% + + + + align:start position:0% + +alright so for more complicated payoffs + + align:start position:0% +alright so for more complicated payoffs + + + align:start position:0% +alright so for more complicated payoffs +the the the life becomes more + + align:start position:0% +the the the life becomes more + + + align:start position:0% +the the the life becomes more +complicated and some finite differences + + align:start position:0% +complicated and some finite differences + + + align:start position:0% +complicated and some finite differences +should be used for more complicated + + align:start position:0% +should be used for more complicated + + + align:start position:0% +should be used for more complicated +payoffs or American payoffs or past the + + align:start position:0% +payoffs or American payoffs or past the + + + align:start position:0% +payoffs or American payoffs or past the +penalty of three methods or Monte colors + + align:start position:0% +penalty of three methods or Monte colors + + + align:start position:0% +penalty of three methods or Monte colors +in simulations and that's what was + + align:start position:0% +in simulations and that's what was + + + align:start position:0% +in simulations and that's what was +happening in real life yeah + + align:start position:0% + + + + align:start position:0% + +now since we have actually a point of + + align:start position:0% +now since we have actually a point of + + + align:start position:0% +now since we have actually a point of +time I I would like to give an example + + align:start position:0% +time I I would like to give an example + + + align:start position:0% +time I I would like to give an example +of how replicating idea of replicating + + align:start position:0% +of how replicating idea of replicating + + + align:start position:0% +of how replicating idea of replicating +portfolio works I give a couple of more + + align:start position:0% +portfolio works I give a couple of more + + + align:start position:0% +portfolio works I give a couple of more +examples so so okay here is a Bloomberg + + align:start position:0% +examples so so okay here is a Bloomberg + + + align:start position:0% +examples so so okay here is a Bloomberg +screen for foreign options call options + + align:start position:0% +screen for foreign options call options + + + align:start position:0% +screen for foreign options call options +on IBM stock it's actually was taking a + + align:start position:0% +on IBM stock it's actually was taking a + + + align:start position:0% +on IBM stock it's actually was taking a +while ago a few years ago but for add so + + align:start position:0% +while ago a few years ago but for add so + + + align:start position:0% +while ago a few years ago but for add so +here are different strikes for a call + + align:start position:0% +here are different strikes for a call + + + align:start position:0% +here are different strikes for a call +option the the current price of the + + align:start position:0% +option the the current price of the + + + align:start position:0% +option the the current price of the +stock is 81 point point 14 and here are + + align:start position:0% +stock is 81 point point 14 and here are + + + align:start position:0% +stock is 81 point point 14 and here are +the strikes of of the call so obviously + + align:start position:0% +the strikes of of the call so obviously + + + align:start position:0% +the strikes of of the call so obviously +if if the option is if the option is way + + align:start position:0% +if if the option is if the option is way + + + align:start position:0% +if if the option is if the option is way +out of the money meaning the strike is + + align:start position:0% +out of the money meaning the strike is + + + align:start position:0% +out of the money meaning the strike is +very high compared to to the stock price + + align:start position:0% +very high compared to to the stock price + + + align:start position:0% +very high compared to to the stock price +they the value of the option is 0 if + + align:start position:0% +they the value of the option is 0 if + + + align:start position:0% +they the value of the option is 0 if +it's way in the money in fact it is just + + align:start position:0% +it's way in the money in fact it is just + + + align:start position:0% +it's way in the money in fact it is just +s minus K so s meaning of being 81 and + + align:start position:0% +s minus K so s meaning of being 81 and + + + align:start position:0% +s minus K so s meaning of being 81 and +say the strike being 55 so it's 26 right + + align:start position:0% +say the strike being 55 so it's 26 right + + + align:start position:0% +say the strike being 55 so it's 26 right +there is some difference but actually + + align:start position:0% +there is some difference but actually + + + align:start position:0% +there is some difference but actually +here it's it's a bit small because the + + align:start position:0% +here it's it's a bit small because the + + + align:start position:0% +here it's it's a bit small because the +difference should be judge discounting + + align:start position:0% +difference should be judge discounting + + + align:start position:0% +difference should be judge discounting +as we know right but it's pretty short + + align:start position:0% +as we know right but it's pretty short + + + align:start position:0% +as we know right but it's pretty short +dated options the options they they're + + align:start position:0% +dated options the options they they're + + + align:start position:0% +dated options the options they they're +probably a month a month long so there + + align:start position:0% +probably a month a month long so there + + + align:start position:0% +probably a month a month long so there +is not much discounting so it becomes + + align:start position:0% +is not much discounting so it becomes + + + align:start position:0% +is not much discounting so it becomes +pretty pal it's similar here right so I + + align:start position:0% +pretty pal it's similar here right so I + + + align:start position:0% +pretty pal it's similar here right so I +mean this changes by five these changes + + align:start position:0% +mean this changes by five these changes + + + align:start position:0% +mean this changes by five these changes +by five it's pretty linear but it + + align:start position:0% +by five it's pretty linear but it + + + align:start position:0% +by five it's pretty linear but it +becomes nonlinear around the money + + align:start position:0% +becomes nonlinear around the money + + + align:start position:0% +becomes nonlinear around the money +around current stock price right so we + + align:start position:0% +around current stock price right so we + + + align:start position:0% +around current stock price right so we +do observe this this behavior but to + + align:start position:0% +do observe this this behavior but to + + + align:start position:0% +do observe this this behavior but to +tell the truth here if you were to I + + align:start position:0% +tell the truth here if you were to I + + + align:start position:0% +tell the truth here if you were to I +didn't put the implied volatilities here + + align:start position:0% +didn't put the implied volatilities here + + + align:start position:0% +didn't put the implied volatilities here +but that's actually you would observe + + align:start position:0% +but that's actually you would observe + + + align:start position:0% +but that's actually you would observe +that the world is not black Scholes + + align:start position:0% +that the world is not black Scholes + + + align:start position:0% +that the world is not black Scholes +meaning that what's the assumption of + + align:start position:0% +meaning that what's the assumption of + + + align:start position:0% +meaning that what's the assumption of +black Scholes the assumption of black + + align:start position:0% +black Scholes the assumption of black + + + align:start position:0% +black Scholes the assumption of black +Scholes is that every option for for any + + align:start position:0% +Scholes is that every option for for any + + + align:start position:0% +Scholes is that every option for for any +strike on a given stock and I give an + + align:start position:0% +strike on a given stock and I give an + + + align:start position:0% +strike on a given stock and I give an +expiry would have the same volatility + + align:start position:0% +expiry would have the same volatility + + + align:start position:0% +expiry would have the same volatility +right so if we went through the size of + + align:start position:0% +right so if we went through the size of + + + align:start position:0% +right so if we went through the size of +implying the volatility according to + + align:start position:0% +implying the volatility according to + + + align:start position:0% +implying the volatility according to +black Scholes formula from from the + + align:start position:0% +black Scholes formula from from the + + + align:start position:0% +black Scholes formula from from the +option price which is traded on the + + align:start position:0% +option price which is traded on the + + + align:start position:0% +option price which is traded on the +market and an current price we would + + align:start position:0% +market and an current price we would + + + align:start position:0% +market and an current price we would +find out that actually the the + + align:start position:0% +find out that actually the the + + + align:start position:0% +find out that actually the the +volatility is not is not constant with + + align:start position:0% +volatility is not is not constant with + + + align:start position:0% +volatility is not is not constant with +strike well it's actually skewed well + + align:start position:0% +strike well it's actually skewed well + + + align:start position:0% +strike well it's actually skewed well +actually it's it is smile we would find + + align:start position:0% +actually it's it is smile we would find + + + align:start position:0% +actually it's it is smile we would find +something like this which means that + + align:start position:0% +something like this which means that + + + align:start position:0% +something like this which means that +black hole theory is not perfectly good + + align:start position:0% +black hole theory is not perfectly good + + + align:start position:0% +black hole theory is not perfectly good +right so something more complicated is + + align:start position:0% +right so something more complicated is + + + align:start position:0% +right so something more complicated is +should be done but in some cases we even + + align:start position:0% +should be done but in some cases we even + + + align:start position:0% +should be done but in some cases we even +don't need to do something more + + align:start position:0% +don't need to do something more + + + align:start position:0% +don't need to do something more +complicated one example being so-called + + align:start position:0% +complicated one example being so-called + + + align:start position:0% +complicated one example being so-called +put-call parity right so let's see + + align:start position:0% +put-call parity right so let's see + + + align:start position:0% +put-call parity right so let's see +suppose we look at the screen so we know + + align:start position:0% +suppose we look at the screen so we know + + + align:start position:0% +suppose we look at the screen so we know +all prices for all Co options for all + + align:start position:0% +all prices for all Co options for all + + + align:start position:0% +all prices for all Co options for all +strikes well probably some granularity + + align:start position:0% +strikes well probably some granularity + + + align:start position:0% +strikes well probably some granularity +but we know those but instead of pricing + + align:start position:0% +but we know those but instead of pricing + + + align:start position:0% +but we know those but instead of pricing +a code we need to price a put somehow we + + align:start position:0% +a code we need to price a put somehow we + + + align:start position:0% +a code we need to price a put somehow we +don't know how I am except our stock + + align:start position:0% +don't know how I am except our stock + + + align:start position:0% +don't know how I am except our stock +looks like so we have strong suspicions + + align:start position:0% +looks like so we have strong suspicions + + + align:start position:0% +looks like so we have strong suspicions +it's not exactly log normal so there is + + align:start position:0% +it's not exactly log normal so there is + + + align:start position:0% +it's not exactly log normal so there is +some volatility smile it's not + + align:start position:0% +some volatility smile it's not + + + align:start position:0% +some volatility smile it's not +constantly the world is slightly not + + align:start position:0% +constantly the world is slightly not + + + align:start position:0% +constantly the world is slightly not +black Scholes + + align:start position:0% +black Scholes + + + align:start position:0% +black Scholes +so how how do we price put well let's + + align:start position:0% +so how how do we price put well let's + + + align:start position:0% +so how how do we price put well let's +see + + align:start position:0% + + + + align:start position:0% + +will stare long enough at the payouts of + + align:start position:0% +will stare long enough at the payouts of + + + align:start position:0% +will stare long enough at the payouts of +the : put so what's the payout of of a + + align:start position:0% +the : put so what's the payout of of a + + + align:start position:0% +the : put so what's the payout of of a +call with some strike it looks like this + + align:start position:0% +call with some strike it looks like this + + + align:start position:0% +call with some strike it looks like this +right the payout of the put with the + + align:start position:0% +right the payout of the put with the + + + align:start position:0% +right the payout of the put with the +same strike would look like this so what + + align:start position:0% +same strike would look like this so what + + + align:start position:0% +same strike would look like this so what +if we take we buy a call and sell a put + + align:start position:0% + + + + align:start position:0% + +so this would go like this right + + align:start position:0% +so this would go like this right + + + align:start position:0% +so this would go like this right +straight line looks very much like + + align:start position:0% +straight line looks very much like + + + align:start position:0% +straight line looks very much like +forward right so if we actually subtract + + align:start position:0% +forward right so if we actually subtract + + + align:start position:0% +forward right so if we actually subtract +a stock from here move it from here then + + align:start position:0% + + + + align:start position:0% + +it should be yep + + align:start position:0% + + + + align:start position:0% + +- Kay yeah I think I think I do go to + + align:start position:0% +- Kay yeah I think I think I do go to + + + align:start position:0% +- Kay yeah I think I think I do go to +science correct right and and this is + + align:start position:0% +science correct right and and this is + + + align:start position:0% +science correct right and and this is +just a number right and that's what + + align:start position:0% +just a number right and that's what + + + align:start position:0% +just a number right and that's what +happens at payout so if we take this + + align:start position:0% +happens at payout so if we take this + + + align:start position:0% +happens at payout so if we take this +portfolio if we action now by call + + align:start position:0% +portfolio if we action now by call + + + align:start position:0% +portfolio if we action now by call +seller put and sell stock we know that + + align:start position:0% +seller put and sell stock we know that + + + align:start position:0% +seller put and sell stock we know that +at the end we'll for sure get the K in + + align:start position:0% +at the end we'll for sure get the K in + + + align:start position:0% +at the end we'll for sure get the K in +money right so which means that now so + + align:start position:0% +money right so which means that now so + + + align:start position:0% +money right so which means that now so +this this is at time T so right now it + + align:start position:0% +this this is at time T so right now it + + + align:start position:0% +this this is at time T so right now it +looks to me that if we do write this and + + align:start position:0% +looks to me that if we do write this and + + + align:start position:0% +looks to me that if we do write this and +that's just the current price of the + + align:start position:0% +that's just the current price of the + + + align:start position:0% +that's just the current price of the +stock this should be + + align:start position:0% + + + + align:start position:0% + +right we just need to discount this + + align:start position:0% +right we just need to discount this + + + align:start position:0% +right we just need to discount this +price to two now this amount of cash + + align:start position:0% +price to two now this amount of cash + + + align:start position:0% +price to two now this amount of cash +which means that our put at any time T + + align:start position:0% +which means that our put at any time T + + + align:start position:0% +which means that our put at any time T +is stock minus K right so if we know all + + align:start position:0% +is stock minus K right so if we know all + + + align:start position:0% +is stock minus K right so if we know all +the prices for any strike k if you know + + align:start position:0% +the prices for any strike k if you know + + + align:start position:0% +the prices for any strike k if you know +if we know price of a call we don't need + + align:start position:0% +if we know price of a call we don't need + + + align:start position:0% +if we know price of a call we don't need +any black Scholes or or anything we can + + align:start position:0% +any black Scholes or or anything we can + + + align:start position:0% +any black Scholes or or anything we can +immediately tell everybody how how much + + align:start position:0% +immediately tell everybody how how much + + + align:start position:0% +immediately tell everybody how how much +is either put right so this this + + align:start position:0% +is either put right so this this + + + align:start position:0% +is either put right so this this +relationship is actually called Co put + + align:start position:0% +relationship is actually called Co put + + + align:start position:0% +relationship is actually called Co put +parity and that's again that's that's a + + align:start position:0% +parity and that's again that's that's a + + + align:start position:0% +parity and that's again that's that's a +replicating portfolio it's a + + align:start position:0% +replicating portfolio it's a + + + align:start position:0% +replicating portfolio it's a +simplification possible it's static + + align:start position:0% +simplification possible it's static + + + align:start position:0% +simplification possible it's static +meaning that we fix it now and we don't + + align:start position:0% +meaning that we fix it now and we don't + + + align:start position:0% +meaning that we fix it now and we don't +change it till the till expire so it's + + align:start position:0% +change it till the till expire so it's + + + align:start position:0% +change it till the till expire so it's +it's quite good this way + + align:start position:0% +it's quite good this way + + + align:start position:0% +it's quite good this way +but that's that's how it works + + align:start position:0% +but that's that's how it works + + + align:start position:0% +but that's that's how it works +another example so for this I have + + align:start position:0% +another example so for this I have + + + align:start position:0% +another example so for this I have +actually a picture so again we have the + + align:start position:0% +actually a picture so again we have the + + + align:start position:0% +actually a picture so again we have the +same situation we have prices of cold + + align:start position:0% +same situation we have prices of cold + + + align:start position:0% +same situation we have prices of cold +but instead of pricing a call we want to + + align:start position:0% +but instead of pricing a call we want to + + + align:start position:0% +but instead of pricing a call we want to +price digital so what is digital digital + + align:start position:0% +price digital so what is digital digital + + + align:start position:0% +price digital so what is digital digital +is such a weird contract which payout is + + align:start position:0% +is such a weird contract which payout is + + + align:start position:0% +is such a weird contract which payout is +just step function basically it's a bet + + align:start position:0% +just step function basically it's a bet + + + align:start position:0% +just step function basically it's a bet +on on a stock to to finish above strike + + align:start position:0% +on on a stock to to finish above strike + + + align:start position:0% +on on a stock to to finish above strike +price K right if if at expiry the stock + + align:start position:0% +price K right if if at expiry the stock + + + align:start position:0% +price K right if if at expiry the stock +is above K you get one you get one + + align:start position:0% +is above K you get one you get one + + + align:start position:0% +is above K you get one you get one +dollar if it's below you get nothing + + align:start position:0% +dollar if it's below you get nothing + + + align:start position:0% +dollar if it's below you get nothing +zero right so so such an interesting + + align:start position:0% +zero right so so such an interesting + + + align:start position:0% +zero right so so such an interesting +contract the question is can we price it + + align:start position:0% +contract the question is can we price it + + + align:start position:0% +contract the question is can we price it +given that we know the the practice of + + align:start position:0% +given that we know the the practice of + + + align:start position:0% +given that we know the the practice of +calls so an I suggest we we use the idea + + align:start position:0% +calls so an I suggest we we use the idea + + + align:start position:0% +calls so an I suggest we we use the idea +of replicating portfolio any ideas + + align:start position:0% +of replicating portfolio any ideas + + + align:start position:0% +of replicating portfolio any ideas +how to do it it's my typical typical + + align:start position:0% +how to do it it's my typical typical + + + align:start position:0% +how to do it it's my typical typical +interview question we'll just pretend + + align:start position:0% +interview question we'll just pretend + + + align:start position:0% +interview question we'll just pretend +that your interview yep + + align:start position:0% + + + + align:start position:0% + +the culprit yeah you're absolutely good + + align:start position:0% +the culprit yeah you're absolutely good + + + align:start position:0% +the culprit yeah you're absolutely good +you're you got enough yeah so here here + + align:start position:0% +you're you got enough yeah so here here + + + align:start position:0% +you're you got enough yeah so here here +here how it goes so this is a a strike a + + align:start position:0% +here how it goes so this is a a strike a + + + align:start position:0% +here how it goes so this is a a strike a +right so let's let's buy well buy a call + + align:start position:0% +right so let's let's buy well buy a call + + + align:start position:0% +right so let's let's buy well buy a call +with strike K minus 1/2 and sell a call + + align:start position:0% +with strike K minus 1/2 and sell a call + + + align:start position:0% +with strike K minus 1/2 and sell a call +with with strike K plus 1/2 right that's + + align:start position:0% +with with strike K plus 1/2 right that's + + + align:start position:0% +with with strike K plus 1/2 right that's +we just sold so how the if we combine + + align:start position:0% +we just sold so how the if we combine + + + align:start position:0% +we just sold so how the if we combine +these two well actually if it if this is + + align:start position:0% +these two well actually if it if this is + + + align:start position:0% +these two well actually if it if this is +one yeah this is one it should look + + align:start position:0% +one yeah this is one it should look + + + align:start position:0% +one yeah this is one it should look +something like this + + align:start position:0% + + + + align:start position:0% + +right + + align:start position:0% +right + + + align:start position:0% +right +so how will it look like so obviously + + align:start position:0% +so how will it look like so obviously + + + align:start position:0% +so how will it look like so obviously +here it's zero right then it will be + + align:start position:0% +here it's zero right then it will be + + + align:start position:0% +here it's zero right then it will be +like this right and after that it will + + align:start position:0% +like this right and after that it will + + + align:start position:0% +like this right and after that it will +be what it will be constantly and + + align:start position:0% +be what it will be constantly and + + + align:start position:0% +be what it will be constantly and +because this is key minus 1/2 and this + + align:start position:0% +because this is key minus 1/2 and this + + + align:start position:0% +because this is key minus 1/2 and this +is K plus 1/2 it will be exactly 1 right + + align:start position:0% +is K plus 1/2 it will be exactly 1 right + + + align:start position:0% +is K plus 1/2 it will be exactly 1 right +good + + align:start position:0% +good + + + align:start position:0% +good +so our way payout at the end will be + + align:start position:0% +so our way payout at the end will be + + + align:start position:0% +so our way payout at the end will be +like this so it's good but there is + + align:start position:0% +like this so it's good but there is + + + align:start position:0% +like this so it's good but there is +quite a bit of slope here so how can we + + align:start position:0% +quite a bit of slope here so how can we + + + align:start position:0% +quite a bit of slope here so how can we +do better than this well if we sell it + + align:start position:0% +do better than this well if we sell it + + + align:start position:0% +do better than this well if we sell it +at K minus by that K minus 1/4 and and + + align:start position:0% +at K minus by that K minus 1/4 and and + + + align:start position:0% +at K minus by that K minus 1/4 and and +sell that at K of plus 1/4 and combine + + align:start position:0% +sell that at K of plus 1/4 and combine + + + align:start position:0% +sell that at K of plus 1/4 and combine +just combine those it will be exactly + + align:start position:0% +just combine those it will be exactly + + + align:start position:0% +just combine those it will be exactly +the same but the the level will be 1/2 + + align:start position:0% +the same but the the level will be 1/2 + + + align:start position:0% +the same but the the level will be 1/2 +so we need to buy to buy two of those in + + align:start position:0% +so we need to buy to buy two of those in + + + align:start position:0% +so we need to buy to buy two of those in +to sell two of those right well we might + + align:start position:0% +to sell two of those right well we might + + + align:start position:0% +to sell two of those right well we might +as well go k minus epsilon and K plus + + align:start position:0% +as well go k minus epsilon and K plus + + + align:start position:0% +as well go k minus epsilon and K plus +epsilon so it will be cold price at + + align:start position:0% +epsilon so it will be cold price at + + + align:start position:0% +epsilon so it will be cold price at +strike K minus epsilon minus call price + + align:start position:0% +strike K minus epsilon minus call price + + + align:start position:0% +strike K minus epsilon minus call price +at K plus epsilon divided by two epsilon + + align:start position:0% +at K plus epsilon divided by two epsilon + + + align:start position:0% +at K plus epsilon divided by two epsilon +right this this to epsilon Confucian + + align:start position:0% +right this this to epsilon Confucian + + + align:start position:0% +right this this to epsilon Confucian +needed to rescale back it they were + + align:start position:0% +needed to rescale back it they were + + + align:start position:0% +needed to rescale back it they were +scared back to 2 1 right so in fact if + + align:start position:0% +scared back to 2 1 right so in fact if + + + align:start position:0% +scared back to 2 1 right so in fact if +we go small apps and we need a lot of + + align:start position:0% +we go small apps and we need a lot of + + + align:start position:0% +we go small apps and we need a lot of +box right well and that's how how that + + align:start position:0% +box right well and that's how how that + + + align:start position:0% +box right well and that's how how that +that's that's the approximation of our + + align:start position:0% +that's that's the approximation of our + + + align:start position:0% +that's that's the approximation of our +digital price and that's actually how + + align:start position:0% +digital price and that's actually how + + + align:start position:0% +digital price and that's actually how +how people on the market do do price and + + align:start position:0% +how people on the market do do price and + + + align:start position:0% +how people on the market do do price and +catch the most importantly the the + + align:start position:0% +catch the most importantly the the + + + align:start position:0% +catch the most importantly the the +digital contracts because because Cole + + align:start position:0% +digital contracts because because Cole + + + align:start position:0% +digital contracts because because Cole +Cole contracts are liquid and they are + + align:start position:0% +Cole contracts are liquid and they are + + + align:start position:0% +Cole contracts are liquid and they are +traded on exchanges while digital's are + + align:start position:0% +traded on exchanges while digital's are + + + align:start position:0% +traded on exchanges while digital's are +way less liquid so somebody would go + + align:start position:0% +way less liquid so somebody would go + + + align:start position:0% +way less liquid so somebody would go +again + + align:start position:0% +again + + + align:start position:0% +again +to counterparty enter into digital & + + align:start position:0% +to counterparty enter into digital & + + + align:start position:0% +to counterparty enter into digital & +Hedges on the exchange this to cause + + align:start position:0% +Hedges on the exchange this to cause + + + align:start position:0% +Hedges on the exchange this to cause +physical spread but now tell me is it + + align:start position:0% +physical spread but now tell me is it + + + align:start position:0% +physical spread but now tell me is it +surprising that I mean how well what + + align:start position:0% +surprising that I mean how well what + + + align:start position:0% +surprising that I mean how well what +does it remind you yeah so it's + + align:start position:0% + + + + align:start position:0% + +derivative of the co price by with + + align:start position:0% +derivative of the co price by with + + + align:start position:0% +derivative of the co price by with +respect to to strike right is it is it + + align:start position:0% +respect to to strike right is it is it + + + align:start position:0% +respect to to strike right is it is it +surprising how did our Co price look + + align:start position:0% +surprising how did our Co price look + + + align:start position:0% +surprising how did our Co price look +like it's a ramp right if we take a + + align:start position:0% +like it's a ramp right if we take a + + + align:start position:0% +like it's a ramp right if we take a +derivative of this what what what vulgar + + align:start position:0% +derivative of this what what what vulgar + + + align:start position:0% +derivative of this what what what vulgar +yeah so it's just so in fact if we do + + align:start position:0% +yeah so it's just so in fact if we do + + + align:start position:0% +yeah so it's just so in fact if we do +something even more weird with this I + + align:start position:0% +something even more weird with this I + + + align:start position:0% +something even more weird with this I +don't know take a square or or something + + align:start position:0% +don't know take a square or or something + + + align:start position:0% +don't know take a square or or something +something else the same will apply right + + align:start position:0% +something else the same will apply right + + + align:start position:0% +something else the same will apply right +so it's not surprising at all all right + + align:start position:0% +so it's not surprising at all all right + + + align:start position:0% +so it's not surprising at all all right +so that's that's basically how how the + + align:start position:0% +so that's that's basically how how the + + + align:start position:0% +so that's that's basically how how the +duplicate this idea of replicating + + align:start position:0% +duplicate this idea of replicating + + + align:start position:0% +duplicate this idea of replicating +portfolios is is it extremely powerful + + align:start position:0% +portfolios is is it extremely powerful + + + align:start position:0% +portfolios is is it extremely powerful +and in fact that's that's what happens + + align:start position:0% +and in fact that's that's what happens + + + align:start position:0% +and in fact that's that's what happens +in in real life in real life you have + + align:start position:0% +in in real life in real life you have + + + align:start position:0% +in in real life in real life you have +some complicated derivative which you + + align:start position:0% +some complicated derivative which you + + + align:start position:0% +some complicated derivative which you +need to hedge and how to hedge you finds + + align:start position:0% +need to hedge and how to hedge you finds + + + align:start position:0% +need to hedge and how to hedge you finds +something else which replicate the to + + align:start position:0% +something else which replicate the to + + + align:start position:0% +something else which replicate the to +certain extent replicates your payoff + + align:start position:0% +certain extent replicates your payoff + + + align:start position:0% +certain extent replicates your payoff +that's what you'll try to do and that + + align:start position:0% +that's what you'll try to do and that + + + align:start position:0% +that's what you'll try to do and that +this will be your hedge portfolio + + align:start position:0% +this will be your hedge portfolio + + + align:start position:0% +this will be your hedge portfolio +usually it's dynamic so you you'll have + + align:start position:0% +usually it's dynamic so you you'll have + + + align:start position:0% +usually it's dynamic so you you'll have +to rebound and that's how you you + + align:start position:0% +to rebound and that's how you you + + + align:start position:0% +to rebound and that's how you you +basically reduce the risks \ No newline at end of file diff --git a/V0z_f7qxLcY.txt b/V0z_f7qxLcY.txt new file mode 100644 index 0000000000000000000000000000000000000000..1b60c6aae86865d6a9561103e57f03526d450377 --- /dev/null +++ b/V0z_f7qxLcY.txt @@ -0,0 +1,2165 @@ +All right. +Good morning all. + +Today we embark on another new +chapter in what we do. + +And the topic is going to be -- + +We will talk about this thing +called an Operational Amplifier. + +Before I get into the lecture, +I want to point out a couple of + +things. +One is that you are going to + +hear about two big words in +today's lecture. + +Two big and incredibly +important words. + +And I want to mention those +words to you right now so that + +when I come to them in lecture +you can say OK, + +I better pay really close +attention, these are important + +words. +All right. + +One of them is abstraction. +The second one is feedback. + +Two incredibly important +concepts. + +Abstraction, +you have been seeing a couple + +times during this course, +once in the beginning where we + +abstracted out Maxwell's +equations by focusing on a + +smaller playground and simply +using KVL, KCL in place of those + +equations. +A big abstraction. + +It turns out that almost all of +EECS is based upon abstractions + +at various levels. +In the first lecture, + +I also showed you the layer +upon layer of abstraction that + +we built to be able to build +interesting systems. + +The second big thing is +feedback. + +And I am going to relate this +to anti-lock breaks in cars. + +And so, you can wait and see +how we do that. + +It's an incredibly important +concept. + +Before we dive into the +amplifier abstraction, + +let me first talk about +something that you know. + +Start with something that you +know and then lead up into the + +operational amplifier and its +circuits. + +You know about the MOSFET +amplifier. + +The MOSFET amplifier that you +know about looked like this. + +It was based on a MOSFET. + +There was a VS supply. +There was a vI input, + +a vO output and, +as I said, a VS supply. + +So, this was a MOSFET circuit +that you've seen before. + +One way of viewing this is that +this circuit has three major + +ports. +This here is the input port + +with voltage vI. +This here, between the drain + +terminal and the ground, +is the output port. + +I take the output between the +drain terminal and ground. + +And, finally, +we have a third port, + +which is this one. +It is called the power port. + +I apply VS between this +terminal here and the ground + +terminal. +And that gives us the power + +port. +This device here was a three + +port device. +Input port or control port, + +output port and a power port. +And so we looked at the circuit + +and did a whole bunch of +analyses of it. + +Then what I can do at this +point, now that you've seen + +this, it's often times +interesting to think about + +abstracting this out into some +kind of a building block. + +Much like in software, +you write a procedure and you + +abstract out the internal +details of the procedure in the + +procedure declaration and in the +call that you make. + +In the same way, +we can take this little device + +here and abstract that out into +the following abstraction. + +We could abstract that out as a +device that looks like this. + +I have my input port, +I have my output port and I + +have my power port. +So, I can apply VS here. + +Notice that I've taken these +six terminals here, + +one, two, three, +four, five and six, + +and put a box around it. +And just exposed the terminals + +to you. +And I need to tell you a little + +bit more about the internal +properties, but suffice it to + +say that you can begin working +with this little block. + +An even simpler version of this +for many applications might just + +look like this, +vI and vO where there is a + +ground that is shared among them +that is implicit in this + +picture. +And vI and vO can simply be the + +node voltages at these nodes. +This is a progressively more + +abstract representation of this +amplifier. + +What we can do is, +provided we know, + +we can abstract out the +relevant properties of this + +block and expose them outside. +And the relevant properties + +might well be that, +let's say here the properties + +may be that I in is always zero. +I can also express to you the + +gain of this amplifier. +I may also be able to tell you + +the Thevenin equivalent for the +output. + +There are some properties that +I can give you that will let you + +use this building block +abstractly. + +Today, what we will do is +introduce a powerful abstraction + +of a type of amplifier. +This is called the operational + +amplifier or "op amp" for short. +What I am going to do is give + +you a slightly more involved +building block than the one I + +have shown you there. +But suffice it to say that the + +idea is going to be the same. +This building block looks like + +this. +This building block has an + +input port. +This building block also has a + +port in which to connect power +or the power port. + +And the way I am going to +connect power, + +I am going to connect a plus VS +supply here. + +That is going to be my ground +node. + +And I am going to connect a +minus VS supply to this node + +here. +So, these voltages are both VS. + +I want to apply a plus VS here +and a negative VS out here. + +And I am going to take the +output between the ground node + +and the output node of the +operational amplifier and call + +that a vO. +This is the output port. + +So, input port and output port +and a power port. + +Think of this as a pattern +where I have an input port + +across which I connect the +input. + +I have a power port across +which I connect a plus VS, + +minus VS supply, +and then I take the output + +terminal and take a ground +terminal, which is defined by + +external components of my +circuitry, and use this as my + +reference node. +Remember ground is just a + +reference node. +I am going to use this as a + +reference node. +These two are equal in + +magnitude. +And take this as my output. + +And when I do something like +this, I can build an even + +simpler, so this is an abstract +differential input amplifier. + +In other words, +this amplifier is going to + +amplify whatever I apply at the +input. + +A slightly more abstract +representation of this looks + +like this. +vOUT and plus/minus vIN. + +This is a slightly more +abstract representation where, + +remember, we are going to draw +this again and again, + +maybe at least 38 or 39 times +in this course. + +And, remember, +each time you draw it, + +remember that there is an +implicit power port, + +a plus/minus supply that is +connected which we don't show. + +And I remember when I first +learned about it a long time ago + +there was a confusion in me +initially. + +How does this work? +Where is the power coming from? + +Just remember that power comes +from a plus/minus supply, + +and we just don't show that in +this abstraction. + +Now, the details, +a lot of details are in Chapter + +16 of your course notes. +That's the reading for that. + +The other thing is that there +are some other key properties of + +this amplifier. +And let me discuss those very + +quickly. +First of all, + +I can draw a circuit model for +the amplifier. + +Make some room for myself here. +And this is a circuit model for + +what we call the ideal +operational amplifier. + +And the circuit model is going +to look like this. + +This is an abstract device. +And, in terms of analyzing how + +this behaves in a circuit, +I am going to show you this + +abstract circuit that looks as +follows. + +Some input v is applied at +these two terminals here. + +And this terminal is called my +v plus terminal and this is + +called my v minus terminal, +so this corresponds to these + +two terminals. +I am telling you that the + +current going in is going to be +zero, so i plus is going to be + +zero and i minus is going to be +zero. + +i plus is the current in here +and i minus is the current into + +the v minus terminal, +and both these currents are + +going to be zero in this device +here. + +The output is going to look +like this. + +Let me just call it vOUT to be +consistent with this here. + +And taken with ground as my +reference. + +The output is simply Av. +In other words, + +what I am doing is I am going +to model this as a device that + +has a dependent source at its +output. + +And the dependent source here +is a voltage controlled voltage + +source. +It is a dependent source, + +it is a voltage controlled +voltage source such that the + +output voltage is A times the +voltage v across its input. + +This is actually very simple. +Think of these three terminals + +I have shown you here. +I applied input across these. + +And the output is going to be A +times whatever I applied. + +And A is going to tend towards +infinity. + +A is going to be huge. +And specific values for A might + +be a hundred thousand or a +million or things of that sort. + +Huge A in this abstract +amplifier. + +In addition to that, +the other properties are that + +it is going to have infinite +input resistance. + +That means looking in this +looks like an open circuit. + +The fact that this is open here +implies the infinite input + +resistance across this port. +What about the output here? + +Remember, this is a voltage +source. + +And we have a zero output +resistance, which means that no + +matter how the load affects +this, as I apply a load this is + +going to behave like an ideal +voltage source and keep holding + +the voltage constant based on +whatever the function I + +establish here. +And A is virtually infinite. + +Let me pause there for a few +seconds and just dwell on this + +so you just understand what the +basic device is. + +Following this basic +definition, I am just going to + +build a whole bunch of fun +little circuits. + +The analysis will be pretty +straightforward, + +but this is a big conceptual +leap here where there is some + +circuitry inside. +Containing resistors, + +MOSFETs, a whole bunch of stuff +in there. + +I am not telling you what is +inside it. + +Much like I could build an +abstract amplifier, + +I could put an abstract box +around the amplifier you saw + +earlier, I want to put a box +around some circuitry. + +I am not telling you what the +circuitry is. + +And, if you are curious, +you should look at page 581 of + +your course notes. +There is an example solved. + +The example is for a +differential amplifier. + +This is the small signal +analysis chapter. + +That differential amplifier +that's solved in that example is + +usually the first stage in an +operational amplifier circuit. + +That differential amplifier is +the first stage at the input. + +And that differential +amplifier, as the name implies, + +amplifies not a single voltage +but amplifies a differential + +voltage. +Note that this guy amplifies + +the voltage difference between +these two terminals. + +That's v here. +And v is simply the same as v + +plus minus v minus. +It's the node voltage here + +minus the node voltage here. +That is what's amplified. + +It amplifies a difference. +Therefore, it is called a + +difference amplifier or a +differential amplifier. + +And so that input stage is what +is inside the op amp. + +It's got a bunch of other +circuitry like level shifters + +and so on. +And at the output it has got a + +buffer. +At at the output it has + +something that is reminiscent of +the source follower circuit that + +you learned about in +recitations, solved an example + +in the course notes and in your +homework as well. + +And you solved a variant of the +source follower on your quiz as + +well in problem two. +So, a circuit that looks like + +that appears at the output. +Remember, for the source + +follower, the resistance looking +in from the output was very, + +very small. +You have seen some of the + +pieces that go inside the +amplifier, but we will deal with + +this as a building block and +simply represent it using this + +abstract little circuit. +To dwell on this a little + +longer, this little device here +is the workhorse of the analog + +industry. +Much like your primitive gate + +abstraction, your inverter and +NAND gate and so on, + +much as your primitive inverter +or NAND gate was from the + +foundations of the digital +industry. + +Remember we learned how to +build this little abstract + +device called a NAND gate or an +inverter? + +We noticed that those form the +foundations of very complicated + +microprocessors. +Those were the building blocks + +of the digital industry. +In the same way, + +this little beast here is the +building block of the analog + +industry. +Just to give you an analogy + +from software, +think of this abstract little + +device as a library routine from +a library of functions when you + +program in C++ or whatever. +Can someone give me an example + +of an incredibly popular routine +that we use all the time that + +may be called the workhorse of +the software industry? + +Pardon? +An abstraction, + +an abstract procedure. +One example might be something + +like a printf. +Printf is an abstract name for + +a procedure that goes and does +something for you. + +It is amazing how we take the +lowly printf for granted. + +I stick my printf into my +program, it includes the + +standard IO library and it goes +and prints a value. + +You won't believe how +complicated the printf is. + +As you go into learning more +advanced software subjects, + +implementing the printf is a +nightmare. + +It is horrendously complicated. +Just imagine. + +You give it a string and it has +to go and print that on your + +terminal or on your Windows +system or whatever. + +Think of the complicated steps +it has to go through. + +But, as far as you're +concerned, it's simple. + +Just print out something and +you're done. + +The same way. +Think of this as the printf of + +the analog business. +It is really simple, + +and the analysis is going to be +incredibly simple, + +it will be mind-bogglingly +simple, but inside it, + +heavens forbid if you look +inside it. + +Tell you what, +go into to S-T-D-I-O dot in one + +of the library routines and just +pore through printf. + +The world's worst horrendous +macros are in there. + +I mean it is just nasty. +The same way inside the op amp, + +it is nasty. +You don't want to go there. + +Much like in your C programming +in your classes, + +you were able to use printf +without fully knowing how it was + +implemented. +Probably some MIT god or some + +key graduate implemented it, +but once it was implemented you + +just used it based on simple +abstract rules as to how it + +behaved. +You didn't have to know what + +was inside it to use it. +The same way with the + +operational amplifier. +So, just think of printf when + +you see this and just imagine +how simple it is going to be to + +use it. +You may think that I spend way + +too much time, +ten minutes dwelling on this + +abstract concept, +but I like to dwell on things + +that I think are incredibly +important. + +The concept of abstraction is +very important. + +And it's not just in software. +The concept of abstraction + +pervades all of EECS. +And if I were to give you a + +project to say go and ask every +professor what is the one word + +that you think best describes +all of EECS? + +Just pick one word. +Go ask every single professor + +you know. +What is a single word? + +If you were to characterize all +of EECS with just one word, + +what might that word be? +In my mind, it is the A word, + +abstraction. +It is all over. + +If you do a grep on all the +words used by all your + +professors in your four years +here, I promise you the first + +one will be know. +And the second one will be + +abstraction. +Check it out. + +See if what I am saying is true +or not. + +It is all over the place. +In 6.001, how many times do you + +think the word abstraction was +used in 6.001? + +It's all over the map. +It's the A word all over. + +Imagine your shock when you see +it being used in 002 because the + +same concept applies. +We build more complicated + +systems by abstracting out the +details of lesser objects, + +and then using those to build +the more complicated systems. + +Abstraction is a very powerful +mechanism of dealing with + +complexity. +Next step is how do I go about + +using the op amp? +Let me show you how it looks on + +a scope. +What I am going to do is apply + +input to the op amp, +I am going to look at the + +output, place the resistor RL to +ground and look at the output. + +And here I am going to apply a +plus VS and out here a minus VS. + +Again, remember that a plus VS +simply looks like this and a + +minus VS simply looks like this. +It's just an inverted VS + +applied here so I get a minus VS +at this input. + +First of all, +what I would like to do is as I + +change vIN, I am going to plot +for you how vOUT looks. + +vIN and this is vO. +I am going to plot vIN in terms + +of microvolts and vO in volts. +vIN is going to have a very + +very small, the scale is going +to be in microvolts because + +remember the gain of this is +huge. + +It's on the order of ten to the +sixth. + +It's huge. +Small changes in vIN are going + +to cause massive changes in vO. +I have a very fine scale on the + +X axis. +What is going to happen if I + +somehow magically make vIN +exactly zero? + +If I short these two terminals, +if this was a completely ideal + +op amp, which it never is, +if it's a completely ideal op + +amp, then my output should be +zero. + +As I increase my vIN the output +should be A times vIN. + +For some small value of vIN, +small v, let's say one + +microvolt, the output should be +one volt. + +A is a constant so this would +look like a straight line. + +And let's say my supply +voltages are 12 volts minus 12 + +volts, if this were an ideal +amplifier and I didn't have to + +worry about the supply, +this would just go on extending + +forever. +But I have a plus 12 volt + +supply and a minus 12 volt +supply. + +My output cannot go past those +limits. + +And so, therefore, +my output kind of flattens out + +at these two points. +And it is called hitting the + +rails. +Output goes up and you hear a + +thunk sound and you hit the +rails. + +When you play with op amps in +your next lab, + +if you listen really, +really carefully you may hear + +it. +So, this saturates out. + +Not surprisingly, +this region where the output + +saturates at the supply is +called the saturation region. + +Remember, don't confuse it +with-- It's not the same as your + +saturation in the MOSFET. +It is a totally different + +thing. +It is just happenstance that we + +call this saturation. +And if you would like to think + +about it, you can think of it as +the thunk region. + +That's probably more +appropriate to distinguish it + +from the saturation region in +the MOSFET. + +And, not surprisingly, +this one is called the active + +region. +And it is in this region that + +we use the op amp. +Here it has hit the rails and + +is kind of dangling out there. +It's not much use to us. + +It's in this active region that +we use it because this is where + +the gain is seen. +Now, it turns out that this is + +a very high gain device. +It is very skittish. + +This gain is kind of a really +funny thing. + +It's dependent on a bunch of +factors. + +This could be temperature +dependent. + +This gain here and this curve +is just completely skittish. + +It could depend on temperature. +It could depend on time of day. + +It could depend on what +medication this amplifier is on. + +It could depend on its mood +swings. + +Who knows what? +This is kind of unstable. + +And A in particular is highly +unstable. + +It is going to be big, +that's for sure, + +but it could be ten to the six, +on a rainy day it might be two + +times ten to the six. +If it feeling sleepy it may be + +point five times ten to the +sixth. + +It is big but I cannot rely on +it. + +Let me show you an example. +I want to show you this curve + +for this MOSFET, +apply an input and plotting the + +output. +What I will do is take a look + +at this curve. +Then what I am going to do is + +use a heat gun to heat the op +amp and you are going to see + +this vary all over the map. +If you still remember last + +week, some of you may remember +that from some place in a + +similar situation where the gm +for the MOSFETs you were given + +was also dependent on +temperature and stuff like that. + +It is a very common occurrence. +And that is certainly the case + +for the MOSFET. + +Let's apply input. +Let's do this. + +This is vIN versus vOUT for the +amplifier. + +Notice that this is plus 12 +volts, this is minus 12 volts. + +It is about two volts per +division. + +This axis here is in +microvolts, I believe. + +For a very small change, +for a few tens of microvolts, + +I have an incredibly high gain. +Notice that this has an + +incredibly high gain here. +The gain is the slope of this + +line, almost a vertical line. +What I am going to do next, + +is to have some fun, +is I am going to heat the op + +amp. +To show you that A is kind of + +really skittish and also the +fact that it doesn't quite hit + +zero, it does all kinds of weird +things, I am going to heat the + +op amp. +And then let's take a look at + +how that curve fluctuates. + +What you saw there was that the +op amp began to behave really + +weirdly as I heated it. +Instead of doing this it + +sometimes did this really +weirdly, like getting an offset + +from the center and so on. +And it does a bunch of other + +weird things, +but we won't go into those + +details. +It's not relevant for this + +course. +But the point is that the gain + +and the offset at the input are +dependent on temperature. + +And we look for ways to make it +less dependent on temperature. + +As the next step, +what I would like to do is + +build a circuit. +This is model equivalent of + +your Hello World program. +We are going to use the printf + +and build a small program on the +printf. + +You don't have to worry about +how printf is implemented, + +just that we can build very +highly interesting circuits with + +this horrendously complicated +function based on a simple + +abstraction of the device. +The circuit that we will build + +is called a noninverting +amplifier. + +From now on, +I am not going to show you the + +plus/minus VS. +I am not going to show the + +power port, but it is in there. +It's hidden under the + +abstraction layer. +This is my op amp. + +And I am going to build the +following circuit. + +This is my v plus and this is +my v minus. + +What I am going to do is for +the v plus I shall apply a vIN. + +Let me talk a little bit about +ground as well. + +Ground is commonly taken as the +point at which I connect my VS + +and minus VS supply. +It is kind of at the midpoint. + +And if VS and minus VS are very +carefully tuned then the output + +is also going to be at that same +ground reference when the input + +is zero. +So, the ground is defined as + +the point at which I connect my +plus/minus VS supplies. + +I apply my vIN out here. +Then what I am going to do, + +here is my output vO. +I am going to have a resistive + +divider to ground here and label +these R1 and R2. + +And what I am going to do here +is feed this back to the input, + +to the v minus input. +I am going to sample the + +voltage here and feed that into +here. + +So, this is my abstract model +and this is my Hello World + +program. +What we are going to do is + +simply analyze how this little +program behaves. + +So, my equivalent circuit +model. + +The way to analyze these is +after one or two of these + +examples, you will be able to +directly analyze this just by + +looking at it, +by inspection. + +But, much as we did for the +other pieces, + +let me grunge through drawing +the equivalent circuit and + +grinding through the analysis, +and then show you the much + +simpler way of doing it. +And even here, + +even with this grinding +analysis, it is going to be + +pretty simple in any case. +So, I will replace the op amp + +with its equivalent circuit +model. + +Its equivalent circuit was v +plus, v minus. + +So, that was the equivalent +circuit model of the operational + +amplifier, just this piece. +I draw that for you. + +Then what I am going to do is I +connect my v in here. + +And, remember, +I have an R1, + +R2 resistive divider here. +And this one gets connected to + +this terminal there. +I also know that i plus is + +zero. +I also know that i minus is + +zero. +All I've done is simply + +replaced the amplifier with its +equivalent circuit. + +Let's go ahead and analyze that +circuit now. + +Let's go ahead and analyze that +circuit. + +And it's going to be pretty +simple, actually. + +What I am going to show you is +the hard way of doing it. + +I will show you a much easier +way, but the hard way itself is + +pathetically easy. +What I want to do is find vO in + +terms of vIN. +And there will be a bunch of + +other factors thrown in, +including things like R1 and + +R2, A and stuff like that. +Let's go and analyze it. + +vO, let's look at that circuit. +By the way, let me take 30 + +seconds and make a little speech +at this point. + +When you see circuits like +this, and I saw this happen in + +quiz two as well, +for some reason, + +when you see a new kind of +circuit, don't completely go + +berserk or freeze or whatever. +There is just no reason to. + +You know the node method. +The node method is the + +workhorse of our business. +When in doubt apply the node + +method. +It will simply work. + +Don't freeze. +Don't think oh, + +man, I need to apply a pattern +that I know already. + +I must have seen this +somewhere. + +When in doubt boom, +apply the node method. + +This circuit here, +all I have here is one unknown + +node voltage. +I know the voltage of v plus, + +I need to compute the voltage +vO. + +There are two unknowns, +vO is an unknown and the + +voltage here at v minus is +another unknown. + +This is a very simple circuit +involving a dependent voltage + +controlled voltage source, +and you need to find out vO and + +v minus using the node method. +Just apply it. + +It's simple. +Don't freeze. + +Just look at it and say I can +do it and apply the node method. + +It will simply work. +So, let's do that. + +What I can do here is vO is A +times v plus minus v minus. + +This is actually really simple. +And then, if I take v plus + +here, I know v plus is simply +vIN so I will just make that + +substitution right away. +So, v plus is simply vIN. + +What is v minus? +v minus here is vO -- + +What is v plus? +I'm sorry, v minus. + +v minus is simply the voltage +that is between R1 and R2. + +Notice that no current flows in +to the v minus node. + +There is no current flowing in. +Voltage at v minus is simply + +the voltage given by the +resistive divider, + +which is vO times R2 divided by +R1 plus R2. + +Stare at that for another +second. + +The voltage at this node here +is simply given by the resistive + +divider. +Because no current is flowing + +in this direction. +And no current flows in because + +I am telling you there is no +current there based on my + +abstraction. +I am telling you i minus is + +zero. +That voltage is simply the + +voltage at this resistive +divider. + +And so I can simplify it +further and write this as vO. + +So I get, there is a one here. +And I move this thing over to + +this side so I get one plus A +times R2 divided by R1 plus R2. + +And that is equal to AvIN. +And simplifying it some more, + +I get vO is AvIN divided by one +plus AR2 divided by R1 plus R2. + +Notice how simple this is, +and this is the hard method. + +All I have done is analyze the +circuit using the basic circuit + +analysis principle that you +learned the first week of the + +course, and I have the output +for you. + +I just noted very carefully +what the relationships were + +between the various elements in +the abstraction. + +Notice here that I am told that +A is extremely large. + +A is on the order of ten to the +six and so on. + +And suppose it is the case +that, let me write that down + +again. +vO is AvIN, one plus AR2, + +R2. +Suppose R1 and R2 are more or + +less comparable and A is ten to +the six, it's a huge number, + +so this whole number is much, +much greater than one. + +If it is much huger than one, +what I can do is I can then + +write this as follows. +I can say that this is more or + +less equal to AvIN divided by +AR2 divided by R1 plus R2. + +I am ignoring the one here. +As soon as I do that, + +notice I can cancel out A and I +get vO to be approximately equal + +to vIN times R1 plus R2 divided +by R2. + +Notice now that when the gain +is very large the output is a + +function of the input multiplied +by some number. + +The beauty of this thing here +is that when A is very large, + +or this expression is very +large, A cancels out and there + +is no A in this relationship. +This means that even though the + +basic amplifier was very +skittish, the output here + +relates to the input based on +components that I have control + +over. +These are soldiers in my army. + +I control them. +So, to give you a sense of some + +numbers here, +suppose A was ten to the six. + +And I choose R1 to be 9R. +And R to be some R. + +Then vO is ten to the sixth vIN +divided by one plus ten to the + +six R divided by 9R plus R. +So, that is ten to the six vIN + +divided by one plus ten to the +six divided by ten. + +All right. +If I ignore the one here, + +the ten to the six and ten to +the six cancel out, + +this ends up giving me 10vIN. +So, I get a really nice + +amplifier whose output is simply +ten times the input and + +determined solely by some +resistor values. + +Let me show you another quick +demo this time and show you the + +amplifier again, +but with resistors connected + +like that. +And then I show you that I want + +to heat the amplifier to the +wazoo, the op amp to the wazoo, + +but vO is going to be +absolutely rock solid. + +Let's try that out. + +This time around, +this is the transfer function, + +the vO versus vIN. +And notice that this time + +around I have similar scales on +the X and Y axes, + +and this has a slope of 10. +This is the point where the + +amplifier saturates at plus 12 +volts, and this is minus 12 + +volts, and this point here is a +zero. + +So, this is vIN, +vOUT, plus 12, + +minus 12 and this slope is 10. +What I am going to do now is + +heat the op amp to the wazoo and +this ain't going to change + +because it's my external +resistors that control it + +independent of the value of A, +provided A continues to be very + +large. +I am just articulating the + +vOUT, vIN curve. +And let me start heating the op + +amp. + +Notice that it's pretty stable. +It doesn't change because it is + +independent of the amplifier +values. + +What I have done now is by +connecting these resistors in + +this way, I have a nice +amplifier with a gain of ten. + +The question you may ask +yourselves is why? + +There is this little sucker in +there that wants to shoot things + +up by ten to the sixth. +Wants to knock things off the + +one rail or the negative rail. +Why is it that it's behaving + +like a docile lamb here and +giving us a nice little factor + +of ten gain no matter what I do +to it? + +Why is it doing that? +What is the intuition behind + +it? +I will draw something on the + +board, but for the next ten +seconds I want you think about + +it. +See if you can come up with + +some insight as to why is it +doing that. + +Why is it exactly ten? +Why isn't the ten to the sixth + +kind of killing me somehow? +Why am I getting exactly ten no + +matter what happens? +See if you can come up with + +some intuition and then I will +show you how it works. + +I will redraw the circuit in +the meantime. + +Let me see if I can give you +some intuition. + +This is my circuit, +and let's say this is R and + +this is R. +As an example, + +let's assume that the input is +5 volts, vIN is 5 volts. + +If R and R are equal, +what should the output be? + +It's R and R, +so it's R1 plus R2 divided by + +R2, right? +It's 2R divided by R, + +so it has a gain of two. +My amplifier has a gain of two + +because R1 plus R2 divided by +R2, which is my gain, + +is R plus R divided by R equals +two. + +So, this will be 10 volts. +If that is 10 volts this is + +going to be 5 volts, +correct? + +This R and R, +voltage divider, + +this is five, +so I get 5 volts here. + +This is v plus. +This is v minus. + +I get R and R, +5 volts here, + +that's how the circuit looks. +Now let's understand what is + +going on. +And listen very carefully. + +This is going to be a key +insight that I hope you will + +carry with you for the rest of +your lives. + +This is really, +really key. + +What you are going to see is, +I think, the third big ah-ha + +moment in 6.002. +Like small signal analysis, + +like the frequency domain stuff +we saw, I think this is the + +third big one in the next 30 or +40 seconds, things that are + +completely either not +necessarily intuitive but are + +just spectacular in terms of +what they can do for you. + +Let's see. +Let's suppose that because I am + +heating it, let's suppose that A +suddenly tends to increase. + +It wants to increase because I +have heated it. + +A is saying I want to get out +this mold here and starts to + +break through its shackles here. +Let's say, as a Gedanken + +experiment, that it tries to +shoot up this to 12 volts. + +It tries to push it up higher. +This is just a Gedanken + +experiment. +The up arrow says that the + +increase in A is trying to push +up vO momentarily. + +Let's see what happens. +It is trying to push up vO + +momentarily, so let's say this +goes to 12 hypothetically. + +If that goes to 12, +what should this volt node go + +to? +Six, exactly. + +This goes to 6 volts. +If that goes to six, + +what does v minus go to? +6 volts again. + +So, v minus goes to 6 volts. +Now at the input I have 5 volts + +at v plus and 6 volts at v +minus, so where should the + +output go? +The output should go down + +because the voltage of the +negative terminal is higher. + +And so the output is A times v +plus minus v minus. + +And because this has gone down, +this has gone up here it is + +going to try to pull the output +down. + +That is going to pull the +output down let's say to 9 volts + +or something. +Cachunk, there is a big battle + +going on here. +A has gone up, + +it has boosted it up to 12, +but the moment that goes to 12, + +this goes to 6, +this goes to 6, + +and the op amp output has to go +down to 9 volts now because this + +input is higher here. +If this goes to 9, + +this goes to 4.5. +If that goes to 4.5, + +this goes to 4.5. +What happens now? + +If this goes to 4.5, +what happens? + +It wants to go back up. +Can't it make up its mind? + +This guy wants to go back up +now because v plus is higher + +than v minus. +What am I seeing here? + +This whole circuit here behaves +like my little son, + +my 9-year-old. +If say do this, + +he wants to do the exact +opposite. + +So, there is a trick in how you +make them do things for you. + +Look at this. +Because of this arrangement of + +the circuit when A tries to push +the output up, + +the rest of the circuit tries +to pull it back down to where it + +used to be. +If the circuit tries not to + +follow the true path, +the rest of the circuit tries + +to whack it into shape so it +follows a true path. + +And what's happening is +because, in this arrangement, + +I have fed back a portion of +the output to the negative + +input. +I have fed back some of the + +output to the negative input. +And by providing this feedback + +of a portion of the output to +the negative input, + +I have arranged it in a way +that I have something called + +negative feedback. +What negative feedback does is + +that if this wanted to go wild +and crazy, the circuit provides + +it with some negative feedback +like you just saw. + +Feedback, a big word. +If you take a poll of all the + +EECS faculty, +I suspect that feedback would + +rank at least as the ninth or +tenth most important word in the + +EECS. +If abstract is number one, + +I think this would rank like a +nine or a ten or something. + +So, that's the reason why it +worked. + +In the last couple of minutes, +let me give you some insight, + +based on something that you +know, on how feedback works. + +This is a road here. +Let's look at anti lock breaks. + +This is my tire. +And let's say I have a set of + +disk brakes here. +As the car is moving forward, + +if I apply the brakes the tire +stops rolling, + +but if I apply the breaks too +hard it can lock up the tire and + +the whole car can skid. +The way anti lock breaks work + +is as follows. +There is a controller that sits + +here. +And there is a little person + +looking at the wheel and seeing +is it turning. + +So, this is a feedback. +And it is saying is it turning? + +Yes. +Or, is it not turning? + +No. +All this person watching the + +tire is doing is saying is it +turning or is it not turning. + +That is it. +That is a negative feedback. + +And so, if it is no and if it +is yes. + +If it is yes then what this +does is it applies the brakes + +even more strongly. +It is turning so I can apply + +more brakes. +But if it says oops, + +it stopped turning, +what it does is it simply + +releases, the controller +releases the brakes. + +And when the controller +releases the brakes this one + +tends to loosen up a little bit +and the tire starts turning + +again. +So, this way you are constantly + +keeping the tire in its region +of critical friction so that it + +is constantly moving. +And static friction applies to + +how hard you can brake and it +doesn't start skidding. + +In fact, if you take your car +out, and I don't say you do + +this. +Let's say go onto the Charles + +River in the dead of winter and +you drive on the lake and you + +slam your anti lock brakes on, +on an icy patch, + +you will notice that there is a +constant sound that looks like + +something is vibrating in there. +That is exactly what is + +happening. +Oops, the tire is locked. + +Release the brakes. +The wheel is turning. + +Jam the brakes on. +That is exactly what is + +happening. +The same way as out there, + +you notice that oops, +the output is going up, + +pull it down, +oops, it's going down, + +pull it up. +So, there is constant negative + +feedback that is keeping the +output stable. + +A very important concept. +And I will ask your recitation + +instructors to cover the very +simple method that is on page 9. \ No newline at end of file diff --git a/V3Wg_jrMSQY.txt b/V3Wg_jrMSQY.txt new file mode 100644 index 0000000000000000000000000000000000000000..2984973d250fe00486006a00172f1f0203223d61 --- /dev/null +++ b/V3Wg_jrMSQY.txt @@ -0,0 +1,12240 @@ +align:start position:0% + +so let's continue with our discussion of + + align:start position:0% +so let's continue with our discussion of + + + align:start position:0% +so let's continue with our discussion of +the derivative + + align:start position:0% + + + + align:start position:0% + +let me recall that + + align:start position:0% +let me recall that + + + align:start position:0% +let me recall that +the derivative of a function if it + + align:start position:0% +the derivative of a function if it + + + align:start position:0% +the derivative of a function if it +exists + + align:start position:0% + + + + align:start position:0% + +which we denote by f prime of c this is + + align:start position:0% +which we denote by f prime of c this is + + + align:start position:0% +which we denote by f prime of c this is +the + + align:start position:0% +the + + + align:start position:0% +the +limit as x goes to c of f of x minus f + + align:start position:0% +limit as x goes to c of f of x minus f + + + align:start position:0% +limit as x goes to c of f of x minus f +of c + + align:start position:0% +of c + + + align:start position:0% +of c +over x minus + + align:start position:0% +over x minus + + + align:start position:0% +over x minus +c okay + + align:start position:0% +c okay + + + align:start position:0% +c okay +last time + + align:start position:0% +last time + + + align:start position:0% +last time +we + + align:start position:0% +we + + + align:start position:0% +we +looked at the relationship between + + align:start position:0% +looked at the relationship between + + + align:start position:0% +looked at the relationship between +continuity + + align:start position:0% +continuity + + + align:start position:0% +continuity +and differentiability + + align:start position:0% +and differentiability + + + align:start position:0% +and differentiability +and showed that differentiability + + align:start position:0% +and showed that differentiability + + + align:start position:0% +and showed that differentiability +implies continuity + + align:start position:0% +implies continuity + + + align:start position:0% +implies continuity +but that having a derivative is quite a + + align:start position:0% +but that having a derivative is quite a + + + align:start position:0% +but that having a derivative is quite a +miraculous + + align:start position:0% +miraculous + + + align:start position:0% +miraculous +thing + + align:start position:0% +thing + + + align:start position:0% +thing +because there are continuous functions + + align:start position:0% +because there are continuous functions + + + align:start position:0% +because there are continuous functions +which we actually constructed + + align:start position:0% +which we actually constructed + + + align:start position:0% +which we actually constructed +we constructed a continuous function you + + align:start position:0% +we constructed a continuous function you + + + align:start position:0% +we constructed a continuous function you +can generalize that example + + align:start position:0% + + + + align:start position:0% + +so we constructed a continuous function + + align:start position:0% +so we constructed a continuous function + + + align:start position:0% +so we constructed a continuous function +that has + + align:start position:0% +that has + + + align:start position:0% +that has +that is differentiable nowhere so + + align:start position:0% +that is differentiable nowhere so + + + align:start position:0% +that is differentiable nowhere so +in fact + + align:start position:0% +in fact + + + align:start position:0% +in fact +you know differentiability is a much + + align:start position:0% +you know differentiability is a much + + + align:start position:0% +you know differentiability is a much +stronger + + align:start position:0% +stronger + + + align:start position:0% +stronger +condition than continuity and it's it's + + align:start position:0% +condition than continuity and it's it's + + + align:start position:0% +condition than continuity and it's it's +something of a miracle + + align:start position:0% + + + + align:start position:0% + +you know just as a side note if you go + + align:start position:0% +you know just as a side note if you go + + + align:start position:0% +you know just as a side note if you go +on to study complex analysis + + align:start position:0% +on to study complex analysis + + + align:start position:0% +on to study complex analysis +which are functions of a complex + + align:start position:0% +which are functions of a complex + + + align:start position:0% +which are functions of a complex +variable rather than a real variable you + + align:start position:0% +variable rather than a real variable you + + + align:start position:0% +variable rather than a real variable you +also have the notion of a derivative + + align:start position:0% +also have the notion of a derivative + + + align:start position:0% +also have the notion of a derivative +there + + align:start position:0% +there + + + align:start position:0% +there +and + + align:start position:0% +and + + + align:start position:0% +and +then the derivative is much more + + align:start position:0% +then the derivative is much more + + + align:start position:0% +then the derivative is much more +miraculous um + + align:start position:0% +miraculous um + + + align:start position:0% +miraculous um +uh than it is here in in the setting of + + align:start position:0% +uh than it is here in in the setting of + + + align:start position:0% +uh than it is here in in the setting of +r + + align:start position:0% +r + + + align:start position:0% +r +but the whole point is the derivative is + + align:start position:0% +but the whole point is the derivative is + + + align:start position:0% +but the whole point is the derivative is +something of a miracle + + align:start position:0% +something of a miracle + + + align:start position:0% +something of a miracle +so today the goal is to + + align:start position:0% +so today the goal is to + + + align:start position:0% +so today the goal is to +prove some properties about the + + align:start position:0% +prove some properties about the + + + align:start position:0% +prove some properties about the +derivatives you know + + align:start position:0% +derivatives you know + + + align:start position:0% +derivatives you know +most of these you know + + align:start position:0% +most of these you know + + + align:start position:0% +most of these you know +maybe you didn't cover the proofs of + + align:start position:0% +maybe you didn't cover the proofs of + + + align:start position:0% +maybe you didn't cover the proofs of +them in calculus + + align:start position:0% + + + + align:start position:0% + +with the ultimate goal of proving + + align:start position:0% +with the ultimate goal of proving + + + align:start position:0% +with the ultimate goal of proving +the mean value theorem which is + + align:start position:0% +the mean value theorem which is + + + align:start position:0% +the mean value theorem which is +to me kind of + + align:start position:0% +to me kind of + + + align:start position:0% +to me kind of +you know + + align:start position:0% +you know + + + align:start position:0% +you know +probably + + align:start position:0% +probably + + + align:start position:0% +probably +the most underappreciated but most + + align:start position:0% +the most underappreciated but most + + + align:start position:0% +the most underappreciated but most +important um + + align:start position:0% +important um + + + align:start position:0% +important um +result in calculus + + align:start position:0% +result in calculus + + + align:start position:0% +result in calculus +now you + + align:start position:0% +now you + + + align:start position:0% +now you +could argue that probably the hero of + + align:start position:0% +could argue that probably the hero of + + + align:start position:0% +could argue that probably the hero of +the story of calculus is the fundamental + + align:start position:0% +the story of calculus is the fundamental + + + align:start position:0% +the story of calculus is the fundamental +theorem of calculus which connects + + align:start position:0% +theorem of calculus which connects + + + align:start position:0% +theorem of calculus which connects +integration which will cover next after + + align:start position:0% +integration which will cover next after + + + align:start position:0% +integration which will cover next after +differentiation + + align:start position:0% +differentiation + + + align:start position:0% +differentiation +which so the fundamental theorem of + + align:start position:0% +which so the fundamental theorem of + + + align:start position:0% +which so the fundamental theorem of +calculus connects integration and + + align:start position:0% +calculus connects integration and + + + align:start position:0% +calculus connects integration and +differentiation + + align:start position:0% +differentiation + + + align:start position:0% +differentiation +so that really is but + + align:start position:0% +so that really is but + + + align:start position:0% +so that really is but +and that is really the hero of calculus + + align:start position:0% +and that is really the hero of calculus + + + align:start position:0% +and that is really the hero of calculus +gets used more + + align:start position:0% +gets used more + + + align:start position:0% +gets used more +than + + align:start position:0% +than + + + align:start position:0% +than +anything else + + align:start position:0% + + + + align:start position:0% + +but + + align:start position:0% +but + + + align:start position:0% +but +to prove that + + align:start position:0% +to prove that + + + align:start position:0% +to prove that +you use the mean value theorem + + align:start position:0% +you use the mean value theorem + + + align:start position:0% +you use the mean value theorem +so you know + + align:start position:0% +so you know + + + align:start position:0% +so you know +if the fundamental theorem of calculus + + align:start position:0% +if the fundamental theorem of calculus + + + align:start position:0% +if the fundamental theorem of calculus +was batman + + align:start position:0% +was batman + + + align:start position:0% +was batman +i would say the mean value theorem is + + align:start position:0% +i would say the mean value theorem is + + + align:start position:0% +i would say the mean value theorem is +something like alfred + + align:start position:0% +something like alfred + + + align:start position:0% +something like alfred +you know he's he's really the reason why + + align:start position:0% +you know he's he's really the reason why + + + align:start position:0% +you know he's he's really the reason why +batman gets to be who he is + + align:start position:0% + + + + align:start position:0% + +um + + align:start position:0% +um + + + align:start position:0% +um +all right enough analogies for now let's + + align:start position:0% +all right enough analogies for now let's + + + align:start position:0% +all right enough analogies for now let's +go back to proving some + + align:start position:0% +go back to proving some + + + align:start position:0% +go back to proving some +properties of the derivative + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +first let's do + + align:start position:0% + + + + align:start position:0% + +some basic + + align:start position:0% +some basic + + + align:start position:0% +some basic +the basic linearity and + + align:start position:0% +the basic linearity and + + + align:start position:0% +the basic linearity and +rules for the derivative so + + align:start position:0% +rules for the derivative so + + + align:start position:0% +rules for the derivative so +let f + + align:start position:0% + + + + align:start position:0% + +go from i to r i is always some interval + + align:start position:0% +go from i to r i is always some interval + + + align:start position:0% +go from i to r i is always some interval +um + + align:start position:0% + + + + align:start position:0% + +then + + align:start position:0% +then + + + align:start position:0% +then +if f + + align:start position:0% +if f + + + align:start position:0% +if f +so i have two functions f and g from i + + align:start position:0% +so i have two functions f and g from i + + + align:start position:0% +so i have two functions f and g from i +to r c is a point in i + + align:start position:0% +to r c is a point in i + + + align:start position:0% +to r c is a point in i +and + + align:start position:0% +and + + + align:start position:0% +and +and the conclusion is if f + + align:start position:0% + + + + align:start position:0% + +and + + align:start position:0% + + + + align:start position:0% + +g are + + align:start position:0% + + + + align:start position:0% + +differentiable at + + align:start position:0% +differentiable at + + + align:start position:0% +differentiable at +c + + align:start position:0% +c + + + align:start position:0% +c +then + + align:start position:0% + + + + align:start position:0% + +we have several + + align:start position:0% +we have several + + + align:start position:0% +we have several +rules that we can apply the first is + + align:start position:0% +rules that we can apply the first is + + + align:start position:0% +rules that we can apply the first is +basically the linearity + + align:start position:0% + + + + align:start position:0% + +of the derivative that + + align:start position:0% +of the derivative that + + + align:start position:0% +of the derivative that +for all alpha + + align:start position:0% +for all alpha + + + align:start position:0% +for all alpha +and r + + align:start position:0% +and r + + + align:start position:0% +and r +function alpha f + + align:start position:0% +function alpha f + + + align:start position:0% +function alpha f +plus g which now goes from + + align:start position:0% +plus g which now goes from + + + align:start position:0% +plus g which now goes from +i to r + + align:start position:0% +i to r + + + align:start position:0% +i to r +[Applause] + + align:start position:0% + + + + align:start position:0% + +is differentiable at c + + align:start position:0% + + + + align:start position:0% + +and + + align:start position:0% +and + + + align:start position:0% +and +the derivative of the function alpha f + + align:start position:0% +the derivative of the function alpha f + + + align:start position:0% +the derivative of the function alpha f +plus g + + align:start position:0% +plus g + + + align:start position:0% +plus g +prime + + align:start position:0% +prime + + + align:start position:0% +prime +c + + align:start position:0% +c + + + align:start position:0% +c +is + + align:start position:0% +is + + + align:start position:0% +is +alpha times f prime of c plus g prime of + + align:start position:0% +alpha times f prime of c plus g prime of + + + align:start position:0% +alpha times f prime of c plus g prime of +c + + align:start position:0% + + + + align:start position:0% + +i think okay starting right a little + + align:start position:0% +i think okay starting right a little + + + align:start position:0% +i think okay starting right a little +slanted here + + align:start position:0% + + + + align:start position:0% + +second is the + + align:start position:0% + + + + align:start position:0% + +multiplication rule + + align:start position:0% + + + + align:start position:0% + +which is the function f times g + + align:start position:0% + + + + align:start position:0% + +is differentiable + + align:start position:0% +is differentiable + + + align:start position:0% +is differentiable +at c and + + align:start position:0% + + + + align:start position:0% + +the derivative of the product is not the + + align:start position:0% +the derivative of the product is not the + + + align:start position:0% +the derivative of the product is not the +product of the derivatives but + + align:start position:0% +product of the derivatives but + + + align:start position:0% +product of the derivatives but +prime of c g of c + + align:start position:0% +prime of c g of c + + + align:start position:0% +prime of c g of c +plus + + align:start position:0% +plus + + + align:start position:0% +plus +f of c g prime of c + + align:start position:0% + + + + align:start position:0% + +so that's a + + align:start position:0% +so that's a + + + align:start position:0% +so that's a +multiplication rule and then we also + + align:start position:0% +multiplication rule and then we also + + + align:start position:0% +multiplication rule and then we also +also have the quotient rule + + align:start position:0% + + + + align:start position:0% + +and + + align:start position:0% +and + + + align:start position:0% +and +you know just like when you need to + + align:start position:0% +you know just like when you need to + + + align:start position:0% +you know just like when you need to +divide by something you need to assume + + align:start position:0% +divide by something you need to assume + + + align:start position:0% +divide by something you need to assume +that you're never dividing by zero + + align:start position:0% +that you're never dividing by zero + + + align:start position:0% +that you're never dividing by zero +um + + align:start position:0% +um + + + align:start position:0% +um +if + + align:start position:0% +if + + + align:start position:0% +if +g of x does not equal 0. + + align:start position:0% +g of x does not equal 0. + + + align:start position:0% +g of x does not equal 0. +for all x and i + + align:start position:0% +for all x and i + + + align:start position:0% +for all x and i +then the function + + align:start position:0% +then the function + + + align:start position:0% +then the function +f over g + + align:start position:0% + + + + align:start position:0% + +is differentiable + + align:start position:0% +is differentiable + + + align:start position:0% +is differentiable +at c + + align:start position:0% +at c + + + align:start position:0% +at c +and the derivative + + align:start position:0% + + + + align:start position:0% + +is the derivative of the top + + align:start position:0% +is the derivative of the top + + + align:start position:0% +is the derivative of the top +times the bottom minus + + align:start position:0% +times the bottom minus + + + align:start position:0% +times the bottom minus +the top times the derivative of the + + align:start position:0% +the top times the derivative of the + + + align:start position:0% +the top times the derivative of the +bottom + + align:start position:0% +bottom + + + align:start position:0% +bottom +over the bottom square + + align:start position:0% + + + + align:start position:0% + +not prime g of c square + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +um so i'll prove one and two uh three + + align:start position:0% +um so i'll prove one and two uh three + + + align:start position:0% +um so i'll prove one and two uh three +we'll leave as an exercise + + align:start position:0% +we'll leave as an exercise + + + align:start position:0% +we'll leave as an exercise +um + + align:start position:0% + + + + align:start position:0% + +all right so uh for one we just compute + + align:start position:0% +all right so uh for one we just compute + + + align:start position:0% +all right so uh for one we just compute +that + + align:start position:0% +that + + + align:start position:0% +that +the limit as + + align:start position:0% +the limit as + + + align:start position:0% +the limit as +x goes to c of alpha f plus g + + align:start position:0% +x goes to c of alpha f plus g + + + align:start position:0% +x goes to c of alpha f plus g +of x minus alpha f + + align:start position:0% +of x minus alpha f + + + align:start position:0% +of x minus alpha f +plus g + + align:start position:0% +plus g + + + align:start position:0% +plus g +of c + + align:start position:0% +of c + + + align:start position:0% +of c +over x minus c + + align:start position:0% +over x minus c + + + align:start position:0% +over x minus c +this is just by definition + + align:start position:0% + + + + align:start position:0% + +alpha times f of x plus g of x minus + + align:start position:0% +alpha times f of x plus g of x minus + + + align:start position:0% +alpha times f of x plus g of x minus +alpha times f of c plus g of c and so + + align:start position:0% +alpha times f of c plus g of c and so + + + align:start position:0% +alpha times f of c plus g of c and so +this equals the limit + + align:start position:0% +this equals the limit + + + align:start position:0% +this equals the limit +as x goes to c and just uh collecting + + align:start position:0% +as x goes to c and just uh collecting + + + align:start position:0% +as x goes to c and just uh collecting +terms + + align:start position:0% +terms + + + align:start position:0% +terms +alpha times + + align:start position:0% +alpha times + + + align:start position:0% +alpha times +f of x minus f of c + + align:start position:0% +f of x minus f of c + + + align:start position:0% +f of x minus f of c +times x minus + + align:start position:0% +times x minus + + + align:start position:0% +times x minus +c plus + + align:start position:0% + + + + align:start position:0% + +g of x minus g of c + + align:start position:0% +g of x minus g of c + + + align:start position:0% +g of x minus g of c +over x minus c + + align:start position:0% +over x minus c + + + align:start position:0% +over x minus c +and + + align:start position:0% + + + + align:start position:0% + +uh + + align:start position:0% + + + + align:start position:0% + +all of these limits exist so this is + + align:start position:0% +all of these limits exist so this is + + + align:start position:0% +all of these limits exist so this is +just a fixed number the limit as x goes + + align:start position:0% +just a fixed number the limit as x goes + + + align:start position:0% +just a fixed number the limit as x goes +to c of this + + align:start position:0% +to c of this + + + align:start position:0% +to c of this +exists and this exists so by what we + + align:start position:0% +exists and this exists so by what we + + + align:start position:0% +exists and this exists so by what we +know about limits + + align:start position:0% +know about limits + + + align:start position:0% +know about limits +um + + align:start position:0% +um + + + align:start position:0% +um +namely that the + + align:start position:0% +namely that the + + + align:start position:0% +namely that the +limit of the sum is the sum of the + + align:start position:0% +limit of the sum is the sum of the + + + align:start position:0% +limit of the sum is the sum of the +limits and then scalars just pull out of + + align:start position:0% +limits and then scalars just pull out of + + + align:start position:0% +limits and then scalars just pull out of +the limit this is equal to + + align:start position:0% +the limit this is equal to + + + align:start position:0% +the limit this is equal to +alpha times f prime of c + + align:start position:0% +alpha times f prime of c + + + align:start position:0% +alpha times f prime of c +plus g prime of c + + align:start position:0% +plus g prime of c + + + align:start position:0% +plus g prime of c +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so that's the proof of the first one + + align:start position:0% +so that's the proof of the first one + + + align:start position:0% +so that's the proof of the first one +for the proof of the second one + + align:start position:0% + + + + align:start position:0% + +we'll use the fact that uh + + align:start position:0% +we'll use the fact that uh + + + align:start position:0% +we'll use the fact that uh +a function which is con + + align:start position:0% +a function which is con + + + align:start position:0% +a function which is con +differentiable at a point is also + + align:start position:0% +differentiable at a point is also + + + align:start position:0% +differentiable at a point is also +continuous at a point + + align:start position:0% +continuous at a point + + + align:start position:0% +continuous at a point +um + + align:start position:0% +um + + + align:start position:0% +um +so + + align:start position:0% +so + + + align:start position:0% +so +since g + + align:start position:0% + + + + align:start position:0% + +is differentiable let's see + + align:start position:0% + + + + align:start position:0% + +it is + + align:start position:0% +it is + + + align:start position:0% +it is +continuous at c + + align:start position:0% +continuous at c + + + align:start position:0% +continuous at c +ie + + align:start position:0% +ie + + + align:start position:0% +ie +limit as x goes to c + + align:start position:0% +limit as x goes to c + + + align:start position:0% +limit as x goes to c +of g of x + + align:start position:0% +of g of x + + + align:start position:0% +of g of x +equals g of c + + align:start position:0% + + + + align:start position:0% + +now we compute the limit as x goes to c + + align:start position:0% +now we compute the limit as x goes to c + + + align:start position:0% +now we compute the limit as x goes to c +of + + align:start position:0% +of + + + align:start position:0% +of +f times g of x minus f of c + + align:start position:0% +f times g of x minus f of c + + + align:start position:0% +f times g of x minus f of c +times g of c + + align:start position:0% +times g of c + + + align:start position:0% +times g of c +over x minus c + + align:start position:0% + + + + align:start position:0% + +now what i'm going to do is add and + + align:start position:0% +now what i'm going to do is add and + + + align:start position:0% +now what i'm going to do is add and +subtract + + align:start position:0% +subtract + + + align:start position:0% +subtract +f of c times g of x + + align:start position:0% +f of c times g of x + + + align:start position:0% +f of c times g of x +so this i can write as the limit as x + + align:start position:0% +so this i can write as the limit as x + + + align:start position:0% +so this i can write as the limit as x +goes to c + + align:start position:0% +goes to c + + + align:start position:0% +goes to c +of f of x + + align:start position:0% +of f of x + + + align:start position:0% +of f of x +minus f of c + + align:start position:0% +minus f of c + + + align:start position:0% +minus f of c +over x minus c times + + align:start position:0% +over x minus c times + + + align:start position:0% +over x minus c times +g of x + + align:start position:0% + + + + align:start position:0% + +plus + + align:start position:0% +plus + + + align:start position:0% +plus +um + + align:start position:0% +um + + + align:start position:0% +um +now + + align:start position:0% + + + + align:start position:0% + +f of c + + align:start position:0% +f of c + + + align:start position:0% +f of c +times g of x minus g of c + + align:start position:0% +times g of x minus g of c + + + align:start position:0% +times g of x minus g of c +over x minus c + + align:start position:0% + + + + align:start position:0% + +and + + align:start position:0% +and + + + align:start position:0% +and +again so this limit as x goes to c + + align:start position:0% +again so this limit as x goes to c + + + align:start position:0% +again so this limit as x goes to c +exists this is just the derivative of f + + align:start position:0% +exists this is just the derivative of f + + + align:start position:0% +exists this is just the derivative of f +at c + + align:start position:0% +at c + + + align:start position:0% +at c +and we noted that since g is + + align:start position:0% +and we noted that since g is + + + align:start position:0% +and we noted that since g is +differentiable at c g is also continuous + + align:start position:0% +differentiable at c g is also continuous + + + align:start position:0% +differentiable at c g is also continuous +at c meaning the limit as x goes to c of + + align:start position:0% +at c meaning the limit as x goes to c of + + + align:start position:0% +at c meaning the limit as x goes to c of +g of x equals g of c + + align:start position:0% +g of x equals g of c + + + align:start position:0% +g of x equals g of c +this is just a constant f c this goes to + + align:start position:0% +this is just a constant f c this goes to + + + align:start position:0% +this is just a constant f c this goes to +g prime of c so + + align:start position:0% +g prime of c so + + + align:start position:0% +g prime of c so +all these limits exist and therefore we + + align:start position:0% +all these limits exist and therefore we + + + align:start position:0% +all these limits exist and therefore we +get that this is equal to f prime of c + + align:start position:0% +get that this is equal to f prime of c + + + align:start position:0% +get that this is equal to f prime of c +times g of c + + align:start position:0% +times g of c + + + align:start position:0% +times g of c +plus + + align:start position:0% +plus + + + align:start position:0% +plus +f of c + + align:start position:0% +f of c + + + align:start position:0% +f of c +g prime of c and three i'll leave as an + + align:start position:0% +g prime of c and three i'll leave as an + + + align:start position:0% +g prime of c and three i'll leave as an +exercise + + align:start position:0% +exercise + + + align:start position:0% +exercise +okay + + align:start position:0% +okay + + + align:start position:0% +okay +again you know you'll you'll write out + + align:start position:0% +again you know you'll you'll write out + + + align:start position:0% +again you know you'll you'll write out +um + + align:start position:0% + + + + align:start position:0% + +you'll add and subtract something uh to + + align:start position:0% +you'll add and subtract something uh to + + + align:start position:0% +you'll add and subtract something uh to +f of x over g of x minus f of c over g + + align:start position:0% +f of x over g of x minus f of c over g + + + align:start position:0% +f of x over g of x minus f of c over g +of c and use the fact that we have + + align:start position:0% +of c and use the fact that we have + + + align:start position:0% +of c and use the fact that we have +continuity that differentiability at a + + align:start position:0% +continuity that differentiability at a + + + align:start position:0% +continuity that differentiability at a +point implies continuity and just + + align:start position:0% +point implies continuity and just + + + align:start position:0% +point implies continuity and just +evaluate the limit so i'm going to stop + + align:start position:0% +evaluate the limit so i'm going to stop + + + align:start position:0% +evaluate the limit so i'm going to stop +with these two rules + + align:start position:0% + + + + align:start position:0% + +i don't know why i called it the + + align:start position:0% +i don't know why i called it the + + + align:start position:0% +i don't know why i called it the +multiplication rule it's called the + + align:start position:0% +multiplication rule it's called the + + + align:start position:0% +multiplication rule it's called the +product rule + + align:start position:0% +product rule + + + align:start position:0% +product rule +well + + align:start position:0% +well + + + align:start position:0% +well +multiplication and product the same + + align:start position:0% +multiplication and product the same + + + align:start position:0% +multiplication and product the same +thing + + align:start position:0% +thing + + + align:start position:0% +thing +um + + align:start position:0% + + + + align:start position:0% + +but we also have the chain rule which + + align:start position:0% +but we also have the chain rule which + + + align:start position:0% +but we also have the chain rule which +requires + + align:start position:0% +requires + + + align:start position:0% +requires +a little more care to prove + + align:start position:0% +a little more care to prove + + + align:start position:0% +a little more care to prove +um than of what we've done so far for + + align:start position:0% +um than of what we've done so far for + + + align:start position:0% +um than of what we've done so far for +these rules + + align:start position:0% +these rules + + + align:start position:0% +these rules +so + + align:start position:0% + + + + align:start position:0% + +suppose i have two intervals + + align:start position:0% + + + + align:start position:0% + +and then i have a function g going from + + align:start position:0% +and then i have a function g going from + + + align:start position:0% +and then i have a function g going from +i 1 to i 2 + + align:start position:0% +i 1 to i 2 + + + align:start position:0% +i 1 to i 2 +f going from i 2 + + align:start position:0% +f going from i 2 + + + align:start position:0% +f going from i 2 +to r + + align:start position:0% + + + + align:start position:0% + +and suppose + + align:start position:0% +and suppose + + + align:start position:0% +and suppose +g is + + align:start position:0% + + + + align:start position:0% + +differentiable at c + + align:start position:0% +differentiable at c + + + align:start position:0% +differentiable at c +and f + + align:start position:0% +and f + + + align:start position:0% +and f +is + + align:start position:0% + + + + align:start position:0% + +differentiable at gfc + + align:start position:0% + + + + align:start position:0% + +then the function + + align:start position:0% + + + + align:start position:0% + +f of g + + align:start position:0% + + + + align:start position:0% + +which now goes from i 1 to r + + align:start position:0% + + + + align:start position:0% + +this is differentiable + + align:start position:0% +this is differentiable + + + align:start position:0% +this is differentiable +at c + + align:start position:0% +at c + + + align:start position:0% +at c +and the derivative + + align:start position:0% + + + + align:start position:0% + +equals + + align:start position:0% + + + + align:start position:0% + +f prime of g of c + + align:start position:0% +f prime of g of c + + + align:start position:0% +f prime of g of c +times + + align:start position:0% +times + + + align:start position:0% +times +g prime of c + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +okay so + + align:start position:0% +okay so + + + align:start position:0% +okay so +[Applause] + + align:start position:0% + + + + align:start position:0% + +um + + align:start position:0% + + + + align:start position:0% + +so what's the the + + align:start position:0% + + + + align:start position:0% + +basic uh + + align:start position:0% + + + + align:start position:0% + +you know + + align:start position:0% +you know + + + align:start position:0% +you know +what's kind of the basic idea + + align:start position:0% +what's kind of the basic idea + + + align:start position:0% +what's kind of the basic idea +again so this is basic + + align:start position:0% + + + + align:start position:0% + +idea is that + + align:start position:0% +idea is that + + + align:start position:0% +idea is that +we write + + align:start position:0% +we write + + + align:start position:0% +we write +the difference quotient + + align:start position:0% + + + + align:start position:0% + +g of x minus f of + + align:start position:0% +g of x minus f of + + + align:start position:0% +g of x minus f of +g of c over x minus c + + align:start position:0% +g of c over x minus c + + + align:start position:0% +g of c over x minus c +as + + align:start position:0% +as + + + align:start position:0% +as +f of g of x + + align:start position:0% + + + + align:start position:0% + +minus + + align:start position:0% +minus + + + align:start position:0% +minus +g + + align:start position:0% +g + + + align:start position:0% +g +f at + + align:start position:0% +f at + + + align:start position:0% +f at +g of c + + align:start position:0% +g of c + + + align:start position:0% +g of c +times over g of x minus g of c + + align:start position:0% +times over g of x minus g of c + + + align:start position:0% +times over g of x minus g of c +times + + align:start position:0% +times + + + align:start position:0% +times +um + + align:start position:0% +um + + + align:start position:0% +um +g of x + + align:start position:0% +g of x + + + align:start position:0% +g of x +over g of c times x minus c + + align:start position:0% +over g of c times x minus c + + + align:start position:0% +over g of c times x minus c +and + + align:start position:0% +and + + + align:start position:0% +and +um you know let x go to z c and then + + align:start position:0% +um you know let x go to z c and then + + + align:start position:0% +um you know let x go to z c and then +we'll pick up the derivative of g here + + align:start position:0% +we'll pick up the derivative of g here + + + align:start position:0% +we'll pick up the derivative of g here +at c and right here + + align:start position:0% +at c and right here + + + align:start position:0% +at c and right here +uh this is f of something converging to + + align:start position:0% +uh this is f of something converging to + + + align:start position:0% +uh this is f of something converging to +g of c + + align:start position:0% +g of c + + + align:start position:0% +g of c +and so this should be like f prime of g + + align:start position:0% +and so this should be like f prime of g + + + align:start position:0% +and so this should be like f prime of g +is c but the only problem with + + align:start position:0% +is c but the only problem with + + + align:start position:0% +is c but the only problem with +really writing this down is that there + + align:start position:0% +really writing this down is that there + + + align:start position:0% +really writing this down is that there +could be points where + + align:start position:0% +could be points where + + + align:start position:0% +could be points where +g of x equals g of c and then i'm + + align:start position:0% +g of x equals g of c and then i'm + + + align:start position:0% +g of x equals g of c and then i'm +dividing by zero that's not allowed okay + + align:start position:0% +dividing by zero that's not allowed okay + + + align:start position:0% +dividing by zero that's not allowed okay +so + + align:start position:0% +so + + + align:start position:0% +so +writing this expression is meaningless + + align:start position:0% +writing this expression is meaningless + + + align:start position:0% +writing this expression is meaningless +okay + + align:start position:0% +okay + + + align:start position:0% +okay +but we're gonna do something like this + + align:start position:0% +but we're gonna do something like this + + + align:start position:0% +but we're gonna do something like this +in spirit + + align:start position:0% +in spirit + + + align:start position:0% +in spirit +okay where at least when g of x does not + + align:start position:0% +okay where at least when g of x does not + + + align:start position:0% +okay where at least when g of x does not +equal g of c + + align:start position:0% +equal g of c + + + align:start position:0% +equal g of c +this thing kind of equals this thing + + align:start position:0% +this thing kind of equals this thing + + + align:start position:0% +this thing kind of equals this thing +okay + + align:start position:0% + + + + align:start position:0% + +that's uh um + + align:start position:0% +that's uh um + + + align:start position:0% +that's uh um +that's kind of the the basic idea + + align:start position:0% +that's kind of the the basic idea + + + align:start position:0% +that's kind of the the basic idea +okay + + align:start position:0% + + + + align:start position:0% + +so to implement the strategy + + align:start position:0% +so to implement the strategy + + + align:start position:0% +so to implement the strategy +[Applause] + + align:start position:0% + + + + align:start position:0% + +um let's introduce uh + + align:start position:0% +um let's introduce uh + + + align:start position:0% +um let's introduce uh +some notation and a few auxiliary + + align:start position:0% +some notation and a few auxiliary + + + align:start position:0% +some notation and a few auxiliary +functions so first off + + align:start position:0% +functions so first off + + + align:start position:0% +functions so first off +the function we're interested in + + align:start position:0% + + + + align:start position:0% + +taking the derivative f of g let me call + + align:start position:0% +taking the derivative f of g let me call + + + align:start position:0% +taking the derivative f of g let me call +that h of x because i don't have to keep + + align:start position:0% +that h of x because i don't have to keep + + + align:start position:0% +that h of x because i don't have to keep +writing uh + + align:start position:0% +writing uh + + + align:start position:0% +writing uh +f of g of x + + align:start position:0% + + + + align:start position:0% + +let's call d this will be the point g of + + align:start position:0% +let's call d this will be the point g of + + + align:start position:0% +let's call d this will be the point g of +c + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% + + + + align:start position:0% + +we want to show + + align:start position:0% + + + + align:start position:0% + +then that + + align:start position:0% +then that + + + align:start position:0% +then that +h prime of c + + align:start position:0% +h prime of c + + + align:start position:0% +h prime of c +exists and it's equal to + + align:start position:0% +exists and it's equal to + + + align:start position:0% +exists and it's equal to +f prime of d times g prime of c + + align:start position:0% +f prime of d times g prime of c + + + align:start position:0% +f prime of d times g prime of c +yeah + + align:start position:0% +yeah + + + align:start position:0% +yeah +just in this notation i've set up + + align:start position:0% +just in this notation i've set up + + + align:start position:0% +just in this notation i've set up +okay so now let me + + align:start position:0% + + + + align:start position:0% + +define some auxiliary functions u of y + + align:start position:0% +define some auxiliary functions u of y + + + align:start position:0% +define some auxiliary functions u of y +this is going to be essentially the + + align:start position:0% +this is going to be essentially the + + + align:start position:0% +this is going to be essentially the +difference quotient + + align:start position:0% +difference quotient + + + align:start position:0% +difference quotient +of + + align:start position:0% +of + + + align:start position:0% +of +f + + align:start position:0% +f + + + align:start position:0% +f +except at + + align:start position:0% +except at + + + align:start position:0% +except at +a certain point so this is f of y + + align:start position:0% +a certain point so this is f of y + + + align:start position:0% +a certain point so this is f of y +minus f of d + + align:start position:0% +minus f of d + + + align:start position:0% +minus f of d +over y minus d + + align:start position:0% +over y minus d + + + align:start position:0% +over y minus d +when + + align:start position:0% +when + + + align:start position:0% +when +y does not equal d so that this is + + align:start position:0% +y does not equal d so that this is + + + align:start position:0% +y does not equal d so that this is +meaningful + + align:start position:0% +meaningful + + + align:start position:0% +meaningful +and then f prime of d + + align:start position:0% +and then f prime of d + + + align:start position:0% +and then f prime of d +when y + + align:start position:0% +when y + + + align:start position:0% +when y +equals d + + align:start position:0% +equals d + + + align:start position:0% +equals d +and then v of x + + align:start position:0% +and then v of x + + + align:start position:0% +and then v of x +so this is going to be this is going to + + align:start position:0% +so this is going to be this is going to + + + align:start position:0% +so this is going to be this is going to +kind of play the role of you know that + + align:start position:0% +kind of play the role of you know that + + + align:start position:0% +kind of play the role of you know that +first expression i wrote up there f of g + + align:start position:0% +first expression i wrote up there f of g + + + align:start position:0% +first expression i wrote up there f of g +of x minus f of g of c + + align:start position:0% +of x minus f of g of c + + + align:start position:0% +of x minus f of g of c +okay + + align:start position:0% +okay + + + align:start position:0% +okay +um and then v of x this will be + + align:start position:0% +um and then v of x this will be + + + align:start position:0% +um and then v of x this will be +g of x minus g of c + + align:start position:0% +g of x minus g of c + + + align:start position:0% +g of x minus g of c +x minus c when + + align:start position:0% +x minus c when + + + align:start position:0% +x minus c when +x does not equal c + + align:start position:0% +x does not equal c + + + align:start position:0% +x does not equal c +and g prime of c + + align:start position:0% +and g prime of c + + + align:start position:0% +and g prime of c +when x equals c + + align:start position:0% +when x equals c + + + align:start position:0% +when x equals c +okay + + align:start position:0% +okay + + + align:start position:0% +okay +now + + align:start position:0% +now + + + align:start position:0% +now +essentially what + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so + + align:start position:0% + + + + align:start position:0% + +what do we what do we have here + + align:start position:0% + + + + align:start position:0% + +then if i look at f of y + + align:start position:0% +then if i look at f of y + + + align:start position:0% +then if i look at f of y +minus f of d + + align:start position:0% + + + + align:start position:0% + +this is equal to u of y + + align:start position:0% +this is equal to u of y + + + align:start position:0% +this is equal to u of y +times y minus d always right + + align:start position:0% +times y minus d always right + + + align:start position:0% +times y minus d always right +because + + align:start position:0% +because + + + align:start position:0% +because +if y does not equal d + + align:start position:0% +if y does not equal d + + + align:start position:0% +if y does not equal d +then i divide over and i get u of y + + align:start position:0% +then i divide over and i get u of y + + + align:start position:0% +then i divide over and i get u of y +then i get f of y minus f of d on the + + align:start position:0% +then i get f of y minus f of d on the + + + align:start position:0% +then i get f of y minus f of d on the +left hand side over y minus d and that's + + align:start position:0% +left hand side over y minus d and that's + + + align:start position:0% +left hand side over y minus d and that's +equal to u of y by definition and then + + align:start position:0% +equal to u of y by definition and then + + + align:start position:0% +equal to u of y by definition and then +when y equals d i get 0 here and i get 0 + + align:start position:0% +when y equals d i get 0 here and i get 0 + + + align:start position:0% +when y equals d i get 0 here and i get 0 +over here so that's that's clear + + align:start position:0% +over here so that's that's clear + + + align:start position:0% +over here so that's that's clear +and also + + align:start position:0% +and also + + + align:start position:0% +and also +the same here g of x minus g of c equals + + align:start position:0% +the same here g of x minus g of c equals + + + align:start position:0% +the same here g of x minus g of c equals +v of x minus something times x minus c + + align:start position:0% +v of x minus something times x minus c + + + align:start position:0% +v of x minus something times x minus c +okay + + align:start position:0% + + + + align:start position:0% + +all right so we have these two um + + align:start position:0% +all right so we have these two um + + + align:start position:0% +all right so we have these two um +expressions + + align:start position:0% +expressions + + + align:start position:0% +expressions +and one more thing i want to note is + + align:start position:0% +and one more thing i want to note is + + + align:start position:0% +and one more thing i want to note is +that u and v are continuous at y equals + + align:start position:0% +that u and v are continuous at y equals + + + align:start position:0% +that u and v are continuous at y equals +d and x equals c um + + align:start position:0% +d and x equals c um + + + align:start position:0% +d and x equals c um +respectively + + align:start position:0% + + + + align:start position:0% + +so note that + + align:start position:0% +so note that + + + align:start position:0% +so note that +[Applause] + + align:start position:0% + + + + align:start position:0% + +v of y + + align:start position:0% +v of y + + + align:start position:0% +v of y +is + + align:start position:0% + + + + align:start position:0% + +continuous at + + align:start position:0% +continuous at + + + align:start position:0% +continuous at +d + + align:start position:0% +d + + + align:start position:0% +d +and v of + + align:start position:0% +and v of + + + align:start position:0% +and v of +x is + + align:start position:0% +x is + + + align:start position:0% +x is +continuous at c + + align:start position:0% +continuous at c + + + align:start position:0% +continuous at c +so + + align:start position:0% +so + + + align:start position:0% +so +let's look at the proof of that we just + + align:start position:0% +let's look at the proof of that we just + + + align:start position:0% +let's look at the proof of that we just +need to show that the limit as y + + align:start position:0% +need to show that the limit as y + + + align:start position:0% +need to show that the limit as y +goes to d of v of y equals v of d so + + align:start position:0% +goes to d of v of y equals v of d so + + + align:start position:0% +goes to d of v of y equals v of d so +compute the limit as y goes to d + + align:start position:0% +compute the limit as y goes to d + + + align:start position:0% +compute the limit as y goes to d +of v of y + + align:start position:0% +of v of y + + + align:start position:0% +of v of y +now when we look at limits remember + + align:start position:0% +now when we look at limits remember + + + align:start position:0% +now when we look at limits remember +we never + + align:start position:0% +we never + + + align:start position:0% +we never +we're not allowed to put y equals d + + align:start position:0% +we're not allowed to put y equals d + + + align:start position:0% +we're not allowed to put y equals d +in the expression for this limit okay + + align:start position:0% +in the expression for this limit okay + + + align:start position:0% +in the expression for this limit okay +we're always looking at points y close + + align:start position:0% +we're always looking at points y close + + + align:start position:0% +we're always looking at points y close +to d but not equal to d is what i'm what + + align:start position:0% +to d but not equal to d is what i'm what + + + align:start position:0% +to d but not equal to d is what i'm what +i'm saying and so therefore when y is + + align:start position:0% +i'm saying and so therefore when y is + + + align:start position:0% +i'm saying and so therefore when y is +near d + + align:start position:0% +near d + + + align:start position:0% +near d +and not equal to d v of y is given by + + align:start position:0% +and not equal to d v of y is given by + + + align:start position:0% +and not equal to d v of y is given by +uh + + align:start position:0% +uh + + + align:start position:0% +uh +i should this is + + align:start position:0% + + + + align:start position:0% + +should have written u here sorry u + + align:start position:0% +should have written u here sorry u + + + align:start position:0% +should have written u here sorry u +okay + + align:start position:0% +okay + + + align:start position:0% +okay +okay so + + align:start position:0% +okay so + + + align:start position:0% +okay so +we're looking at y near d + + align:start position:0% +we're looking at y near d + + + align:start position:0% +we're looking at y near d +but not equal to d and therefore it's + + align:start position:0% +but not equal to d and therefore it's + + + align:start position:0% +but not equal to d and therefore it's +given by this expression right so this + + align:start position:0% +given by this expression right so this + + + align:start position:0% +given by this expression right so this +is the limit as y goes to d + + align:start position:0% +is the limit as y goes to d + + + align:start position:0% +is the limit as y goes to d +of f of y minus f of d + + align:start position:0% +of f of y minus f of d + + + align:start position:0% +of f of y minus f of d +over y minus d + + align:start position:0% +over y minus d + + + align:start position:0% +over y minus d +and this is just the definition of the + + align:start position:0% +and this is just the definition of the + + + align:start position:0% +and this is just the definition of the +derivative of f at d + + align:start position:0% +derivative of f at d + + + align:start position:0% +derivative of f at d +so remember d is g of c so f is + + align:start position:0% +so remember d is g of c so f is + + + align:start position:0% +so remember d is g of c so f is +differentiable there and this is uh + + align:start position:0% +differentiable there and this is uh + + + align:start position:0% +differentiable there and this is uh +by definition u of d + + align:start position:0% +by definition u of d + + + align:start position:0% +by definition u of d +right so this function u is continuous + + align:start position:0% +right so this function u is continuous + + + align:start position:0% +right so this function u is continuous +at + + align:start position:0% +at + + + align:start position:0% +at +uh y equals d + + align:start position:0% +uh y equals d + + + align:start position:0% +uh y equals d +um + + align:start position:0% +um + + + align:start position:0% +um +and similarly + + align:start position:0% + + + + align:start position:0% + +the limit as x goes to c of u of x v of + + align:start position:0% +the limit as x goes to c of u of x v of + + + align:start position:0% +the limit as x goes to c of u of x v of +x + + align:start position:0% +x + + + align:start position:0% +x +equals v of c + + align:start position:0% + + + + align:start position:0% + +equal which is + + align:start position:0% + + + + align:start position:0% + +g prime of c + + align:start position:0% + + + + align:start position:0% + +okay so now we're going to combine um + + align:start position:0% +okay so now we're going to combine um + + + align:start position:0% +okay so now we're going to combine um +what i've written here + + align:start position:0% + + + + align:start position:0% + +to finish the proof so + + align:start position:0% + + + + align:start position:0% + +then h of x + + align:start position:0% +then h of x + + + align:start position:0% +then h of x +minus h of c + + align:start position:0% + + + + align:start position:0% + +this is equal to f of g of x + + align:start position:0% +this is equal to f of g of x + + + align:start position:0% +this is equal to f of g of x +minus f of + + align:start position:0% +minus f of + + + align:start position:0% +minus f of +g of c + + align:start position:0% +g of c + + + align:start position:0% +g of c +and this is equal to uh + + align:start position:0% +and this is equal to uh + + + align:start position:0% +and this is equal to uh +u of g of x + + align:start position:0% +u of g of x + + + align:start position:0% +u of g of x +times + + align:start position:0% + + + + align:start position:0% + +g of x minus g of c + + align:start position:0% +g of x minus g of c + + + align:start position:0% +g of x minus g of c +this is from this relation here + + align:start position:0% +this is from this relation here + + + align:start position:0% +this is from this relation here +so call this one star + + align:start position:0% + + + + align:start position:0% + +this one double star + + align:start position:0% +this one double star + + + align:start position:0% +this one double star +so this is by star + + align:start position:0% + + + + align:start position:0% + +and now i use uh + + align:start position:0% + + + + align:start position:0% + +the second relation double star to write + + align:start position:0% +the second relation double star to write + + + align:start position:0% +the second relation double star to write +g of x minus g of c equals + + align:start position:0% +g of x minus g of c equals + + + align:start position:0% +g of x minus g of c equals +b of x times + + align:start position:0% +b of x times + + + align:start position:0% +b of x times +x minus c + + align:start position:0% + + + + align:start position:0% + +and therefore + + align:start position:0% + + + + align:start position:0% + +the limit as x goes to c + + align:start position:0% +the limit as x goes to c + + + align:start position:0% +the limit as x goes to c +of um + + align:start position:0% + + + + align:start position:0% + +h of x + + align:start position:0% +h of x + + + align:start position:0% +h of x +minus um + + align:start position:0% +minus um + + + align:start position:0% +minus um +h of c + + align:start position:0% +h of c + + + align:start position:0% +h of c +over x minus c this is equal to the + + align:start position:0% +over x minus c this is equal to the + + + align:start position:0% +over x minus c this is equal to the +limit + + align:start position:0% +limit + + + align:start position:0% +limit +as x goes to c + + align:start position:0% +as x goes to c + + + align:start position:0% +as x goes to c +of u of g of x + + align:start position:0% +of u of g of x + + + align:start position:0% +of u of g of x +times v + + align:start position:0% +times v + + + align:start position:0% +times v +of x + + align:start position:0% +of x + + + align:start position:0% +of x +now + + align:start position:0% +now + + + align:start position:0% +now +u is continuous at g of c g is + + align:start position:0% +u is continuous at g of c g is + + + align:start position:0% +u is continuous at g of c g is +continuous at c + + align:start position:0% +continuous at c + + + align:start position:0% +continuous at c +and we prove that the composition of two + + align:start position:0% +and we prove that the composition of two + + + align:start position:0% +and we prove that the composition of two +continuous functions is continuous + + align:start position:0% +continuous functions is continuous + + + align:start position:0% +continuous functions is continuous +right so + + align:start position:0% +right so + + + align:start position:0% +right so +uh + + align:start position:0% +uh + + + align:start position:0% +uh +this equals + + align:start position:0% +this equals + + + align:start position:0% +this equals +u of g of c + + align:start position:0% +u of g of c + + + align:start position:0% +u of g of c +and v of x we've proven already that + + align:start position:0% +and v of x we've proven already that + + + align:start position:0% +and v of x we've proven already that +limit is v + + align:start position:0% +limit is v + + + align:start position:0% +limit is v +of c + + align:start position:0% +of c + + + align:start position:0% +of c +and u of g of c you know so this is d + + align:start position:0% +and u of g of c you know so this is d + + + align:start position:0% +and u of g of c you know so this is d +remember in in the notation we had + + align:start position:0% +remember in in the notation we had + + + align:start position:0% +remember in in the notation we had +earlier and therefore that equals + + align:start position:0% + + + + align:start position:0% + +f prime of g of c + + align:start position:0% +f prime of g of c + + + align:start position:0% +f prime of g of c +remember g of c was d + + align:start position:0% + + + + align:start position:0% + +times + + align:start position:0% +times + + + align:start position:0% +times +g prime of + + align:start position:0% +g prime of + + + align:start position:0% +g prime of +c okay + + align:start position:0% + + + + align:start position:0% + +so to go from this point to this point + + align:start position:0% +so to go from this point to this point + + + align:start position:0% +so to go from this point to this point +we use the fact that u is continuous at + + align:start position:0% +we use the fact that u is continuous at + + + align:start position:0% +we use the fact that u is continuous at +c which we proved + + align:start position:0% +c which we proved + + + align:start position:0% +c which we proved +um + + align:start position:0% +um + + + align:start position:0% +um +u is continuous at g of c + + align:start position:0% +u is continuous at g of c + + + align:start position:0% +u is continuous at g of c +which we proved over there and that + + align:start position:0% + + + + align:start position:0% + +g is continuous at c + + align:start position:0% +g is continuous at c + + + align:start position:0% +g is continuous at c +and therefore the composition of two + + align:start position:0% +and therefore the composition of two + + + align:start position:0% +and therefore the composition of two +continuous functions is continuous at + + align:start position:0% +continuous functions is continuous at + + + align:start position:0% +continuous functions is continuous at +that point to arrive at uh this guy + + align:start position:0% +that point to arrive at uh this guy + + + align:start position:0% +that point to arrive at uh this guy +okay + + align:start position:0% +okay + + + align:start position:0% +okay +but again the whole basic idea was to be + + align:start position:0% +but again the whole basic idea was to be + + + align:start position:0% +but again the whole basic idea was to be +able to write the difference quotient as + + align:start position:0% +able to write the difference quotient as + + + align:start position:0% +able to write the difference quotient as +kind of a product of + + align:start position:0% +kind of a product of + + + align:start position:0% +kind of a product of +um + + align:start position:0% +um + + + align:start position:0% +um +you know what looks like the difference + + align:start position:0% +you know what looks like the difference + + + align:start position:0% +you know what looks like the difference +quotient of f + + align:start position:0% +quotient of f + + + align:start position:0% +quotient of f +times the difference quotient of g but + + align:start position:0% +times the difference quotient of g but + + + align:start position:0% +times the difference quotient of g but +you have to be careful because g of x + + align:start position:0% +you have to be careful because g of x + + + align:start position:0% +you have to be careful because g of x +could equal g of c + + align:start position:0% +could equal g of c + + + align:start position:0% +could equal g of c +in which case you're dividing by zero in + + align:start position:0% +in which case you're dividing by zero in + + + align:start position:0% +in which case you're dividing by zero in +this you know basic idea we had up there + + align:start position:0% +this you know basic idea we had up there + + + align:start position:0% +this you know basic idea we had up there +which is not allowed + + align:start position:0% +which is not allowed + + + align:start position:0% +which is not allowed +but you get around it by by + + align:start position:0% +but you get around it by by + + + align:start position:0% +but you get around it by by +you know using these uh + + align:start position:0% +you know using these uh + + + align:start position:0% +you know using these uh +functions which equal what you want + + align:start position:0% +functions which equal what you want + + + align:start position:0% +functions which equal what you want +as long as you're not dividing by zero + + align:start position:0% +as long as you're not dividing by zero + + + align:start position:0% +as long as you're not dividing by zero +basically + + align:start position:0% + + + + align:start position:0% + +okay so that wraps it up for basic + + align:start position:0% +okay so that wraps it up for basic + + + align:start position:0% +okay so that wraps it up for basic +properties + + align:start position:0% +properties + + + align:start position:0% +properties +of the derivative + + align:start position:0% +of the derivative + + + align:start position:0% +of the derivative +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +and now we're going to move on to + + align:start position:0% + + + + align:start position:0% + +trying to prove the mean value theorem + + align:start position:0% + + + + align:start position:0% + +the alfred of this + + align:start position:0% +the alfred of this + + + align:start position:0% +the alfred of this +batman tail + + align:start position:0% + + + + align:start position:0% + +um + + align:start position:0% + + + + align:start position:0% + +but first uh in order to prove this + + align:start position:0% +but first uh in order to prove this + + + align:start position:0% +but first uh in order to prove this +we'll need a result about um the + + align:start position:0% +we'll need a result about um the + + + align:start position:0% +we'll need a result about um the +derivative in relation to + + align:start position:0% +derivative in relation to + + + align:start position:0% +derivative in relation to +a certain relative minimum and relative + + align:start position:0% +a certain relative minimum and relative + + + align:start position:0% +a certain relative minimum and relative +maximum so let me first define what this + + align:start position:0% +maximum so let me first define what this + + + align:start position:0% +maximum so let me first define what this +means + + align:start position:0% + + + + align:start position:0% + +let s be a subset of r + + align:start position:0% +let s be a subset of r + + + align:start position:0% +let s be a subset of r +f be a function from s to r + + align:start position:0% + + + + align:start position:0% + +we say f + + align:start position:0% + + + + align:start position:0% + +has a + + align:start position:0% + + + + align:start position:0% + +relative max + + align:start position:0% + + + + align:start position:0% + +at c + + align:start position:0% +at c + + + align:start position:0% +at c +in s + + align:start position:0% + + + + align:start position:0% + +if + + align:start position:0% +if + + + align:start position:0% +if +there exists a delta positive + + align:start position:0% +there exists a delta positive + + + align:start position:0% +there exists a delta positive +such that + + align:start position:0% +such that + + + align:start position:0% +such that +for all x and s + + align:start position:0% +for all x and s + + + align:start position:0% +for all x and s +x minus e is less than delta + + align:start position:0% +x minus e is less than delta + + + align:start position:0% +x minus e is less than delta +then + + align:start position:0% +then + + + align:start position:0% +then +f of x is less than or equal to f c + + align:start position:0% +f of x is less than or equal to f c + + + align:start position:0% +f of x is less than or equal to f c +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so the picture here and then + + align:start position:0% +so the picture here and then + + + align:start position:0% +so the picture here and then +let me um + + align:start position:0% + + + + align:start position:0% + +state that there's + + align:start position:0% + + + + align:start position:0% + +analogous definition + + align:start position:0% + + + + align:start position:0% + +of relative min + + align:start position:0% + + + + align:start position:0% + +at c you just take this entire + + align:start position:0% +at c you just take this entire + + + align:start position:0% +at c you just take this entire +definition and flip the inequality + + align:start position:0% +definition and flip the inequality + + + align:start position:0% +definition and flip the inequality +okay + + align:start position:0% +okay + + + align:start position:0% +okay +that's the definition for relative men + + align:start position:0% +that's the definition for relative men + + + align:start position:0% +that's the definition for relative men +so what this means pictorially so + + align:start position:0% +so what this means pictorially so + + + align:start position:0% +so what this means pictorially so +remember we had this notion of absolute + + align:start position:0% +remember we had this notion of absolute + + + align:start position:0% +remember we had this notion of absolute +min and absolute max an absolute max at + + align:start position:0% +min and absolute max an absolute max at + + + align:start position:0% +min and absolute max an absolute max at +a point c + + align:start position:0% +a point c + + + align:start position:0% +a point c +means every other point um at every + + align:start position:0% +means every other point um at every + + + align:start position:0% +means every other point um at every +other point in s + + align:start position:0% +other point in s + + + align:start position:0% +other point in s +f of x lies below f of c here we're just + + align:start position:0% +f of x lies below f of c here we're just + + + align:start position:0% +f of x lies below f of c here we're just +saying as long as you're close to + + align:start position:0% +saying as long as you're close to + + + align:start position:0% +saying as long as you're close to +um + + align:start position:0% +um + + + align:start position:0% +um +the point c + + align:start position:0% +the point c + + + align:start position:0% +the point c +then you lay below f c so + + align:start position:0% + + + + align:start position:0% + +let's say + + align:start position:0% + + + + align:start position:0% + +let's say our function looks something + + align:start position:0% +let's say our function looks something + + + align:start position:0% +let's say our function looks something +like that + + align:start position:0% + + + + align:start position:0% + +okay so then + + align:start position:0% + + + + align:start position:0% + +uh + + align:start position:0% + + + + align:start position:0% + +say we're at this + + align:start position:0% + + + + align:start position:0% + +here so this would be + + align:start position:0% + + + + align:start position:0% + +absolute max because the graph of the + + align:start position:0% +absolute max because the graph of the + + + align:start position:0% +absolute max because the graph of the +function sits below + + align:start position:0% +function sits below + + + align:start position:0% +function sits below +the value + + align:start position:0% +the value + + + align:start position:0% +the value +of the function at this point for all x + + align:start position:0% +of the function at this point for all x + + + align:start position:0% +of the function at this point for all x +in this uh interval a b okay and then + + align:start position:0% +in this uh interval a b okay and then + + + align:start position:0% +in this uh interval a b okay and then +here at this point + + align:start position:0% + + + + align:start position:0% + +we would have an absolute + + align:start position:0% +we would have an absolute + + + align:start position:0% +we would have an absolute +min right because + + align:start position:0% +min right because + + + align:start position:0% +min right because +the rest of + + align:start position:0% +the rest of + + + align:start position:0% +the rest of +because the graph of the function sits + + align:start position:0% +because the graph of the function sits + + + align:start position:0% +because the graph of the function sits +above that point + + align:start position:0% + + + + align:start position:0% + +for all x in this interval but now if + + align:start position:0% +for all x in this interval but now if + + + align:start position:0% +for all x in this interval but now if +you if i go to this point + + align:start position:0% +you if i go to this point + + + align:start position:0% +you if i go to this point +say + + align:start position:0% + + + + align:start position:0% + +this would be a relative + + align:start position:0% + + + + align:start position:0% + +max + + align:start position:0% +max + + + align:start position:0% +max +okay because why if i look at um + + align:start position:0% +okay because why if i look at um + + + align:start position:0% +okay because why if i look at um +you know an interval small interval + + align:start position:0% +you know an interval small interval + + + align:start position:0% +you know an interval small interval +around it + + align:start position:0% +around it + + + align:start position:0% +around it +and i look inside this interval there's + + align:start position:0% +and i look inside this interval there's + + + align:start position:0% +and i look inside this interval there's +too many dashed lines going on so i'm + + align:start position:0% +too many dashed lines going on so i'm + + + align:start position:0% +too many dashed lines going on so i'm +going to + + align:start position:0% +going to + + + align:start position:0% +going to +erase this + + align:start position:0% + + + + align:start position:0% + +yeah i'm just going to do away with the + + align:start position:0% +yeah i'm just going to do away with the + + + align:start position:0% +yeah i'm just going to do away with the +dash + + align:start position:0% +dash + + + align:start position:0% +dash +if i zoom in on just this one piece of + + align:start position:0% +if i zoom in on just this one piece of + + + align:start position:0% +if i zoom in on just this one piece of +the graph then at this point + + align:start position:0% + + + + align:start position:0% + +the graph sits below this point + + align:start position:0% + + + + align:start position:0% + +inside this um + + align:start position:0% + + + + align:start position:0% + +inside this little vertical strip okay + + align:start position:0% +inside this little vertical strip okay + + + align:start position:0% +inside this little vertical strip okay +so this guy would be a relative max and + + align:start position:0% +so this guy would be a relative max and + + + align:start position:0% +so this guy would be a relative max and +then similarly + + align:start position:0% +then similarly + + + align:start position:0% +then similarly +at this point here maybe it's uh let me + + align:start position:0% + + + + align:start position:0% + +so you can + + align:start position:0% + + + + align:start position:0% + +really see what + + align:start position:0% + + + + align:start position:0% + +graph is + + align:start position:0% +graph is + + + align:start position:0% +graph is +should have brought different colors + + align:start position:0% +should have brought different colors + + + align:start position:0% +should have brought different colors +um + + align:start position:0% +um + + + align:start position:0% +um +at this point + + align:start position:0% +at this point + + + align:start position:0% +at this point +we have relative min + + align:start position:0% +we have relative min + + + align:start position:0% +we have relative min +right because nearby + + align:start position:0% +right because nearby + + + align:start position:0% +right because nearby +nearby points sit above the value of the + + align:start position:0% +nearby points sit above the value of the + + + align:start position:0% +nearby points sit above the value of the +function + + align:start position:0% +function + + + align:start position:0% +function +evaluated at this point okay so + + align:start position:0% +evaluated at this point okay so + + + align:start position:0% +evaluated at this point okay so +relative max means nearby points + + align:start position:0% + + + + align:start position:0% + +f sits below that f f evaluated at that + + align:start position:0% +f sits below that f f evaluated at that + + + align:start position:0% +f sits below that f f evaluated at that +point and relative min is the other way + + align:start position:0% +point and relative min is the other way + + + align:start position:0% +point and relative min is the other way +around + + align:start position:0% +around + + + align:start position:0% +around +okay + + align:start position:0% + + + + align:start position:0% + +so i don't think we need to + + align:start position:0% + + + + align:start position:0% + +belabor the point of what relative men + + align:start position:0% +belabor the point of what relative men + + + align:start position:0% +belabor the point of what relative men +relative maxes are i think that's pretty + + align:start position:0% +relative maxes are i think that's pretty + + + align:start position:0% +relative maxes are i think that's pretty +clear + + align:start position:0% + + + + align:start position:0% + +okay so the theorem + + align:start position:0% + + + + align:start position:0% + +is the following + + align:start position:0% + + + + align:start position:0% + +if f from a b + + align:start position:0% + + + + align:start position:0% + +has a + + align:start position:0% +has a + + + align:start position:0% +has a +relative + + align:start position:0% +relative + + + align:start position:0% +relative +min or + + align:start position:0% +min or + + + align:start position:0% +min or +max + + align:start position:0% +max + + + align:start position:0% +max +at a point c + + align:start position:0% +at a point c + + + align:start position:0% +at a point c +strictly inside this closed interval in + + align:start position:0% +strictly inside this closed interval in + + + align:start position:0% +strictly inside this closed interval in +the open interval a b + + align:start position:0% +the open interval a b + + + align:start position:0% +the open interval a b +then and + + align:start position:0% + + + + align:start position:0% + +f is + + align:start position:0% + + + + align:start position:0% + +differentiable at c + + align:start position:0% + + + + align:start position:0% + +then + + align:start position:0% + + + + align:start position:0% + +f prime of c equals zero right and this + + align:start position:0% +f prime of c equals zero right and this + + + align:start position:0% +f prime of c equals zero right and this +is kind of clear from this picture + + align:start position:0% +is kind of clear from this picture + + + align:start position:0% +is kind of clear from this picture +although this kind of might look more + + align:start position:0% +although this kind of might look more + + + align:start position:0% +although this kind of might look more +like a sawtooth but it shouldn't that + + align:start position:0% +like a sawtooth but it shouldn't that + + + align:start position:0% +like a sawtooth but it shouldn't that +the tangent at this point is uh + + align:start position:0% +the tangent at this point is uh + + + align:start position:0% +the tangent at this point is uh +horizontal and the tangent at this point + + align:start position:0% +horizontal and the tangent at this point + + + align:start position:0% +horizontal and the tangent at this point +is horizontal which just + + align:start position:0% +is horizontal which just + + + align:start position:0% +is horizontal which just +is the expression that + + align:start position:0% +is the expression that + + + align:start position:0% +is the expression that +um was just expressing that f prime of c + + align:start position:0% +um was just expressing that f prime of c + + + align:start position:0% +um was just expressing that f prime of c +equals zero right so f prime of c is + + align:start position:0% +equals zero right so f prime of c is + + + align:start position:0% +equals zero right so f prime of c is +supposed to be the slope of the tangent + + align:start position:0% +supposed to be the slope of the tangent + + + align:start position:0% +supposed to be the slope of the tangent +okay + + align:start position:0% + + + + align:start position:0% + +so the idea of the proof is + + align:start position:0% +so the idea of the proof is + + + align:start position:0% +so the idea of the proof is +and we'll do it for relative max + + align:start position:0% +and we'll do it for relative max + + + align:start position:0% +and we'll do it for relative max +relative min you get by taking minus f + + align:start position:0% +relative min you get by taking minus f + + + align:start position:0% +relative min you get by taking minus f +so we'll do it for + + align:start position:0% + + + + align:start position:0% + +suppose f has a relative max at + + align:start position:0% + + + + align:start position:0% + +c and a b + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +um + + align:start position:0% + + + + align:start position:0% + +so i'm just going to draw a picture um + + align:start position:0% +so i'm just going to draw a picture um + + + align:start position:0% +so i'm just going to draw a picture um +to + + align:start position:0% +to + + + align:start position:0% +to +illustrate why this is the case so + + align:start position:0% +illustrate why this is the case so + + + align:start position:0% +illustrate why this is the case so +why what i'm about to say is the case so + + align:start position:0% +why what i'm about to say is the case so + + + align:start position:0% +why what i'm about to say is the case so +we have a b + + align:start position:0% +we have a b + + + align:start position:0% +we have a b +we have c + + align:start position:0% + + + + align:start position:0% + +then + + align:start position:0% + + + + align:start position:0% + +there exists + + align:start position:0% +there exists + + + align:start position:0% +there exists +delta positive + + align:start position:0% +delta positive + + + align:start position:0% +delta positive +um + + align:start position:0% +um + + + align:start position:0% +um +say delta 1 + + align:start position:0% + + + + align:start position:0% + +such that + + align:start position:0% +such that + + + align:start position:0% +such that +two things are true + + align:start position:0% + + + + align:start position:0% + +x or c minus + + align:start position:0% +x or c minus + + + align:start position:0% +x or c minus +delta 1 + + align:start position:0% +delta 1 + + + align:start position:0% +delta 1 +c plus delta 1 is contained in + + align:start position:0% +c plus delta 1 is contained in + + + align:start position:0% +c plus delta 1 is contained in +a b + + align:start position:0% +a b + + + align:start position:0% +a b +two + + align:start position:0% + + + + align:start position:0% + +for all x and c minus delta one + + align:start position:0% +for all x and c minus delta one + + + align:start position:0% +for all x and c minus delta one +c plus delta one + + align:start position:0% +c plus delta one + + + align:start position:0% +c plus delta one +um + + align:start position:0% +um + + + align:start position:0% +um +f of x is less than or equal to f c + + align:start position:0% +f of x is less than or equal to f c + + + align:start position:0% +f of x is less than or equal to f c +okay so + + align:start position:0% +okay so + + + align:start position:0% +okay so +you know + + align:start position:0% +you know + + + align:start position:0% +you know +delta one is chosen as the minimum of uh + + align:start position:0% +delta one is chosen as the minimum of uh + + + align:start position:0% +delta one is chosen as the minimum of uh +so maybe let me not call it delta let me + + align:start position:0% +so maybe let me not call it delta let me + + + align:start position:0% +so maybe let me not call it delta let me +one let me just call it delta + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +um + + align:start position:0% +um + + + align:start position:0% +um +first off you know that a b + + align:start position:0% +first off you know that a b + + + align:start position:0% +first off you know that a b +open interval this is a an open set + + align:start position:0% +open interval this is a an open set + + + align:start position:0% +open interval this is a an open set +which we've encountered in the + + align:start position:0% +which we've encountered in the + + + align:start position:0% +which we've encountered in the +assignments + + align:start position:0% +assignments + + + align:start position:0% +assignments +so um + + align:start position:0% + + + + align:start position:0% + +you can find a delta + + align:start position:0% +you can find a delta + + + align:start position:0% +you can find a delta +so that + + align:start position:0% + + + + align:start position:0% + +delta 0 say so that this interval + + align:start position:0% +delta 0 say so that this interval + + + align:start position:0% +delta 0 say so that this interval +centered at c is contained in a b + + align:start position:0% +centered at c is contained in a b + + + align:start position:0% +centered at c is contained in a b +right + + align:start position:0% +right + + + align:start position:0% +right +now since + + align:start position:0% +now since + + + align:start position:0% +now since +f has a relative maximum at this point + + align:start position:0% +f has a relative maximum at this point + + + align:start position:0% +f has a relative maximum at this point +there exists another delta one say so + + align:start position:0% +there exists another delta one say so + + + align:start position:0% +there exists another delta one say so +that if + + align:start position:0% +that if + + + align:start position:0% +that if +um + + align:start position:0% + + + + align:start position:0% + +i'm inside that interval + + align:start position:0% +i'm inside that interval + + + align:start position:0% +i'm inside that interval +then f of x is less than or equal to f c + + align:start position:0% +then f of x is less than or equal to f c + + + align:start position:0% +then f of x is less than or equal to f c +for all x in that interval + + align:start position:0% +for all x in that interval + + + align:start position:0% +for all x in that interval +okay and i choose delta to be the + + align:start position:0% +okay and i choose delta to be the + + + align:start position:0% +okay and i choose delta to be the +minimum of these two uh these two deltas + + align:start position:0% +minimum of these two uh these two deltas + + + align:start position:0% +minimum of these two uh these two deltas +and then i will have + + align:start position:0% +and then i will have + + + align:start position:0% +and then i will have +um + + align:start position:0% + + + + align:start position:0% + +a chosen delta so that + + align:start position:0% +a chosen delta so that + + + align:start position:0% +a chosen delta so that +x that c minus delta c plus delta is + + align:start position:0% + + + + align:start position:0% + +so here + + align:start position:0% + + + + align:start position:0% + +this one is + + align:start position:0% + + + + align:start position:0% + +and then delta 0 is chosen so that that + + align:start position:0% +and then delta 0 is chosen so that that + + + align:start position:0% +and then delta 0 is chosen so that that +is contained so i choose the minimum of + + align:start position:0% +is contained so i choose the minimum of + + + align:start position:0% +is contained so i choose the minimum of +these deltas and this is the delta i + + align:start position:0% +these deltas and this is the delta i + + + align:start position:0% +these deltas and this is the delta i +take for for this statement + + align:start position:0% +take for for this statement + + + align:start position:0% +take for for this statement +okay + + align:start position:0% + + + + align:start position:0% + +all right + + align:start position:0% +all right + + + align:start position:0% +all right +so um + + align:start position:0% +so um + + + align:start position:0% +so um +now the way we get that the derivative + + align:start position:0% +now the way we get that the derivative + + + align:start position:0% +now the way we get that the derivative +is zero is we're going to approach uh c + + align:start position:0% +is zero is we're going to approach uh c + + + align:start position:0% +is zero is we're going to approach uh c +from + + align:start position:0% +from + + + align:start position:0% +from +above and + + align:start position:0% +above and + + + align:start position:0% +above and +from below + + align:start position:0% +from below + + + align:start position:0% +from below +and use the um + + align:start position:0% +and use the um + + + align:start position:0% +and use the um +the fact that we have a relative max to + + align:start position:0% +the fact that we have a relative max to + + + align:start position:0% +the fact that we have a relative max to +show that the derivative is both + + align:start position:0% +show that the derivative is both + + + align:start position:0% +show that the derivative is both +uh bigger than or equal to zero and less + + align:start position:0% +uh bigger than or equal to zero and less + + + align:start position:0% +uh bigger than or equal to zero and less +than or equal to zero all right so + + align:start position:0% + + + + align:start position:0% + +let x in be um + + align:start position:0% +let x in be um + + + align:start position:0% +let x in be um +c minus + + align:start position:0% +c minus + + + align:start position:0% +c minus +um how did i write this + + align:start position:0% +um how did i write this + + + align:start position:0% +um how did i write this +delta over 2n which is + + align:start position:0% +delta over 2n which is + + + align:start position:0% +delta over 2n which is +in the + + align:start position:0% + + + + align:start position:0% + +interval c minus delta c + + align:start position:0% +interval c minus delta c + + + align:start position:0% +interval c minus delta c +for all n + + align:start position:0% + + + + align:start position:0% + +then what do we know x in + + align:start position:0% +then what do we know x in + + + align:start position:0% +then what do we know x in +the limit as n goes to infinity of c + + align:start position:0% +the limit as n goes to infinity of c + + + align:start position:0% +the limit as n goes to infinity of c +minus delta over two + + align:start position:0% +minus delta over two + + + align:start position:0% +minus delta over two +n converges to + + align:start position:0% +n converges to + + + align:start position:0% +n converges to +c + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +the + + align:start position:0% +the + + + align:start position:0% +the +derivative at c + + align:start position:0% +derivative at c + + + align:start position:0% +derivative at c +is equal to the limit + + align:start position:0% +is equal to the limit + + + align:start position:0% +is equal to the limit +as n goes to infinity of + + align:start position:0% +as n goes to infinity of + + + align:start position:0% +as n goes to infinity of +f of x sub n minus f of c + + align:start position:0% +f of x sub n minus f of c + + + align:start position:0% +f of x sub n minus f of c +over x sub n minus c + + align:start position:0% +over x sub n minus c + + + align:start position:0% +over x sub n minus c +now + + align:start position:0% +now + + + align:start position:0% +now +um + + align:start position:0% +um + + + align:start position:0% +um +what do we note + + align:start position:0% +what do we note + + + align:start position:0% +what do we note +so x sub n is in this interval here + + align:start position:0% +so x sub n is in this interval here + + + align:start position:0% +so x sub n is in this interval here +which is contained in this interval here + + align:start position:0% +which is contained in this interval here + + + align:start position:0% +which is contained in this interval here +and therefore f of x sub n is always + + align:start position:0% +and therefore f of x sub n is always + + + align:start position:0% +and therefore f of x sub n is always +less than or equal to f of c + + align:start position:0% +less than or equal to f of c + + + align:start position:0% +less than or equal to f of c +so + + align:start position:0% +so + + + align:start position:0% +so +what's on top is always less than or + + align:start position:0% +what's on top is always less than or + + + align:start position:0% +what's on top is always less than or +equal to zero + + align:start position:0% +equal to zero + + + align:start position:0% +equal to zero +okay + + align:start position:0% +okay + + + align:start position:0% +okay +now x sub n is always less than c + + align:start position:0% +now x sub n is always less than c + + + align:start position:0% +now x sub n is always less than c +so this thing on bottom is also less + + align:start position:0% +so this thing on bottom is also less + + + align:start position:0% +so this thing on bottom is also less +than zero + + align:start position:0% +than zero + + + align:start position:0% +than zero +and therefore something that's less than + + align:start position:0% +and therefore something that's less than + + + align:start position:0% +and therefore something that's less than +or equal to zero on top over something + + align:start position:0% +or equal to zero on top over something + + + align:start position:0% +or equal to zero on top over something +that's less than zero on bottom + + align:start position:0% +that's less than zero on bottom + + + align:start position:0% +that's less than zero on bottom +must be bigger than or equal to zero + + align:start position:0% + + + + align:start position:0% + +so that's approaching c from the left if + + align:start position:0% +so that's approaching c from the left if + + + align:start position:0% +so that's approaching c from the left if +we approach c from the right + + align:start position:0% + + + + align:start position:0% + +delta over 2 n which is contained in + + align:start position:0% +delta over 2 n which is contained in + + + align:start position:0% +delta over 2 n which is contained in +c c plus delta + + align:start position:0% +c c plus delta + + + align:start position:0% +c c plus delta +for all n + + align:start position:0% + + + + align:start position:0% + +then + + align:start position:0% +then + + + align:start position:0% +then +x n converges to c + + align:start position:0% +x n converges to c + + + align:start position:0% +x n converges to c +and + + align:start position:0% +and + + + align:start position:0% +and +if we look at f prime of c + + align:start position:0% +if we look at f prime of c + + + align:start position:0% +if we look at f prime of c +again this is equal to + + align:start position:0% +again this is equal to + + + align:start position:0% +again this is equal to +limit as n goes to infinity of f of + + align:start position:0% +limit as n goes to infinity of f of + + + align:start position:0% +limit as n goes to infinity of f of +y sub n minus f of c + + align:start position:0% +y sub n minus f of c + + + align:start position:0% +y sub n minus f of c +over y sub n minus c again + + align:start position:0% +over y sub n minus c again + + + align:start position:0% +over y sub n minus c again +uh f c is a relative maximum so this + + align:start position:0% +uh f c is a relative maximum so this + + + align:start position:0% +uh f c is a relative maximum so this +thing on top is still less than or equal + + align:start position:0% +thing on top is still less than or equal + + + align:start position:0% +thing on top is still less than or equal +to zero + + align:start position:0% +to zero + + + align:start position:0% +to zero +and the thing on bottom though is now + + align:start position:0% +and the thing on bottom though is now + + + align:start position:0% +and the thing on bottom though is now +since y sub n is bigger than c + + align:start position:0% +since y sub n is bigger than c + + + align:start position:0% +since y sub n is bigger than c +this is positive so something on top is + + align:start position:0% +this is positive so something on top is + + + align:start position:0% +this is positive so something on top is +negative something on top is positive so + + align:start position:0% +negative something on top is positive so + + + align:start position:0% +negative something on top is positive so +the limit must be negative + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so we've just shown f prime of c is both + + align:start position:0% +so we've just shown f prime of c is both + + + align:start position:0% +so we've just shown f prime of c is both +bigger than or equal to zero and that + + align:start position:0% +bigger than or equal to zero and that + + + align:start position:0% +bigger than or equal to zero and that +it's also less than or equal to zero + + align:start position:0% + + + + align:start position:0% + +and therefore the derivative is zero + + align:start position:0% +and therefore the derivative is zero + + + align:start position:0% +and therefore the derivative is zero +at this point + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and again the proof for a relative + + align:start position:0% +and again the proof for a relative + + + align:start position:0% +and again the proof for a relative +minimum is is um + + align:start position:0% +minimum is is um + + + align:start position:0% +minimum is is um +you know + + align:start position:0% + + + + align:start position:0% + +very similar except um + + align:start position:0% + + + + align:start position:0% + +except that inequality flips signs + + align:start position:0% +except that inequality flips signs + + + align:start position:0% +except that inequality flips signs +and therefore you would get this is less + + align:start position:0% +and therefore you would get this is less + + + align:start position:0% +and therefore you would get this is less +than or equal to zero this one would be + + align:start position:0% +than or equal to zero this one would be + + + align:start position:0% +than or equal to zero this one would be +bigger than or equal to zero + + align:start position:0% +bigger than or equal to zero + + + align:start position:0% +bigger than or equal to zero +but you still get uh f prime of c is + + align:start position:0% +but you still get uh f prime of c is + + + align:start position:0% +but you still get uh f prime of c is +bounded between zero and zero + + align:start position:0% +bounded between zero and zero + + + align:start position:0% +bounded between zero and zero +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so + + align:start position:0% +so + + + align:start position:0% +so +at a point + + align:start position:0% +at a point + + + align:start position:0% +at a point +where we have a relative minimum + + align:start position:0% +where we have a relative minimum + + + align:start position:0% +where we have a relative minimum +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +strictly inside the interval + + align:start position:0% + + + + align:start position:0% + +um + + align:start position:0% +um + + + align:start position:0% +um +the derivative must be zero okay + + align:start position:0% + + + + align:start position:0% + +and the fact that it happens strictly + + align:start position:0% +and the fact that it happens strictly + + + align:start position:0% +and the fact that it happens strictly +inside the interval is important right + + align:start position:0% +inside the interval is important right + + + align:start position:0% +inside the interval is important right +this is not necessarily um + + align:start position:0% +this is not necessarily um + + + align:start position:0% +this is not necessarily um +true if the relative max or relative min + + align:start position:0% +true if the relative max or relative min + + + align:start position:0% +true if the relative max or relative min +happens at an endpoint right think of f + + align:start position:0% +happens at an endpoint right think of f + + + align:start position:0% +happens at an endpoint right think of f +of x + + align:start position:0% +of x + + + align:start position:0% +of x +equals x on zero one right + + align:start position:0% +equals x on zero one right + + + align:start position:0% +equals x on zero one right +and it has a absolute minimum at zero + + align:start position:0% +and it has a absolute minimum at zero + + + align:start position:0% +and it has a absolute minimum at zero +absolute maximum at one and the + + align:start position:0% +absolute maximum at one and the + + + align:start position:0% +absolute maximum at one and the +derivative is one at both points + + align:start position:0% +derivative is one at both points + + + align:start position:0% +derivative is one at both points +not zero so this is only for relative + + align:start position:0% +not zero so this is only for relative + + + align:start position:0% +not zero so this is only for relative +min + + align:start position:0% +min + + + align:start position:0% +min +relative maxes that occur inside + + align:start position:0% +relative maxes that occur inside + + + align:start position:0% +relative maxes that occur inside +strictly inside the interval that the + + align:start position:0% +strictly inside the interval that the + + + align:start position:0% +strictly inside the interval that the +function's + + align:start position:0% +function's + + + align:start position:0% +function's +defined on and + + align:start position:0% +defined on and + + + align:start position:0% +defined on and +where it's differentiable + + align:start position:0% + + + + align:start position:0% + +okay so now um + + align:start position:0% + + + + align:start position:0% + +we have rolls theorem which is + + align:start position:0% +we have rolls theorem which is + + + align:start position:0% +we have rolls theorem which is +essentially the mean value theorem um + + align:start position:0% +essentially the mean value theorem um + + + align:start position:0% +essentially the mean value theorem um +rotated + + align:start position:0% +rotated + + + align:start position:0% +rotated +we'll get the mean value theorem from + + align:start position:0% +we'll get the mean value theorem from + + + align:start position:0% +we'll get the mean value theorem from +rolle's theorem and which states the + + align:start position:0% +rolle's theorem and which states the + + + align:start position:0% +rolle's theorem and which states the +following + + align:start position:0% + + + + align:start position:0% + +f b from a b to r + + align:start position:0% + + + + align:start position:0% + +b continuous + + align:start position:0% + + + + align:start position:0% + +so it's continuous at every point in a b + + align:start position:0% + + + + align:start position:0% + +differentiable + + align:start position:0% + + + + align:start position:0% + +at + + align:start position:0% +at + + + align:start position:0% +at +every point inside of a b + + align:start position:0% +every point inside of a b + + + align:start position:0% +every point inside of a b +okay it could be differentiable at the + + align:start position:0% +okay it could be differentiable at the + + + align:start position:0% +okay it could be differentiable at the +end point so it's fine but it has to be + + align:start position:0% +end point so it's fine but it has to be + + + align:start position:0% +end point so it's fine but it has to be +differentiable + + align:start position:0% +differentiable + + + align:start position:0% +differentiable +on the open interval a b + + align:start position:0% + + + + align:start position:0% + +of f b a equals f of b equals 0. + + align:start position:0% +of f b a equals f of b equals 0. + + + align:start position:0% +of f b a equals f of b equals 0. +then + + align:start position:0% + + + + align:start position:0% + +there exists a point c + + align:start position:0% +there exists a point c + + + align:start position:0% +there exists a point c +the open interval a b + + align:start position:0% +the open interval a b + + + align:start position:0% +the open interval a b +this is important + + align:start position:0% +this is important + + + align:start position:0% +this is important +such that + + align:start position:0% +such that + + + align:start position:0% +such that +f prime of c equals 0. + + align:start position:0% +f prime of c equals 0. + + + align:start position:0% +f prime of c equals 0. +all right and what's the + + align:start position:0% +all right and what's the + + + align:start position:0% +all right and what's the +what's the picture that goes with this + + align:start position:0% +what's the picture that goes with this + + + align:start position:0% +what's the picture that goes with this +i'm sure you've seen it before + + align:start position:0% + + + + align:start position:0% + +let me draw a function + + align:start position:0% + + + + align:start position:0% + +that looks kind of like sine or cosine + + align:start position:0% +that looks kind of like sine or cosine + + + align:start position:0% +that looks kind of like sine or cosine +but anyways + + align:start position:0% +but anyways + + + align:start position:0% +but anyways +function which is 0 here zero here then + + align:start position:0% +function which is 0 here zero here then + + + align:start position:0% +function which is 0 here zero here then +there has to exist a + + align:start position:0% +there has to exist a + + + align:start position:0% +there has to exist a +point where the tangent + + align:start position:0% + + + + align:start position:0% + +is vertical + + align:start position:0% +is vertical + + + align:start position:0% +is vertical +in fact here + + align:start position:0% + + + + align:start position:0% + +can occur at two different points all + + align:start position:0% +can occur at two different points all + + + align:start position:0% +can occur at two different points all +right + + align:start position:0% +right + + + align:start position:0% +right +but something that's already kind of + + align:start position:0% +but something that's already kind of + + + align:start position:0% +but something that's already kind of +giving the game away as far as how we'll + + align:start position:0% +giving the game away as far as how we'll + + + align:start position:0% +giving the game away as far as how we'll +prove this is + + align:start position:0% +prove this is + + + align:start position:0% +prove this is +um + + align:start position:0% +um + + + align:start position:0% +um +let's look at where the function + + align:start position:0% +let's look at where the function + + + align:start position:0% +let's look at where the function +takes a maximum + + align:start position:0% +takes a maximum + + + align:start position:0% +takes a maximum +and a minimum okay + + align:start position:0% +and a minimum okay + + + align:start position:0% +and a minimum okay +um + + align:start position:0% +um + + + align:start position:0% +um +you know that that is the the heart of + + align:start position:0% +you know that that is the the heart of + + + align:start position:0% +you know that that is the the heart of +the proof + + align:start position:0% + + + + align:start position:0% + +and why can we why does it even have an + + align:start position:0% +and why can we why does it even have an + + + align:start position:0% +and why can we why does it even have an +absolute maximum or absolute minimum + + align:start position:0% +absolute maximum or absolute minimum + + + align:start position:0% +absolute maximum or absolute minimum +um + + align:start position:0% +um + + + align:start position:0% +um +so i guess i didn't say this over there + + align:start position:0% +so i guess i didn't say this over there + + + align:start position:0% +so i guess i didn't say this over there +when i discussed relative min and + + align:start position:0% +when i discussed relative min and + + + align:start position:0% +when i discussed relative min and +relative max but an absolute maximum is + + align:start position:0% +relative max but an absolute maximum is + + + align:start position:0% +relative max but an absolute maximum is +also a relative maximum + + align:start position:0% +also a relative maximum + + + align:start position:0% +also a relative maximum +and + + align:start position:0% +and + + + align:start position:0% +and +absolute minimum is also a relative + + align:start position:0% +absolute minimum is also a relative + + + align:start position:0% +absolute minimum is also a relative +minimum + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +let me make this this is kind of a late + + align:start position:0% +let me make this this is kind of a late + + + align:start position:0% +let me make this this is kind of a late +remark + + align:start position:0% + + + + align:start position:0% + +uh + + align:start position:0% + + + + align:start position:0% + +absolute max + + align:start position:0% + + + + align:start position:0% + +is and + + align:start position:0% +is and + + + align:start position:0% +is and +is a + + align:start position:0% + + + + align:start position:0% + +relative max + + align:start position:0% +relative max + + + align:start position:0% +relative max +absolute men's + + align:start position:0% + + + + align:start position:0% + +is a relative mint + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +all right so um this picture's kind of + + align:start position:0% +all right so um this picture's kind of + + + align:start position:0% +all right so um this picture's kind of +giving the game away already uh let's + + align:start position:0% +giving the game away already uh let's + + + align:start position:0% +giving the game away already uh let's +look at where the function takes a max + + align:start position:0% +look at where the function takes a max + + + align:start position:0% +look at where the function takes a max +and a min + + align:start position:0% +and a min + + + align:start position:0% +and a min +and + + align:start position:0% +and + + + align:start position:0% +and +why can why does f take a max or a min + + align:start position:0% +why can why does f take a max or a min + + + align:start position:0% +why can why does f take a max or a min +it's because f is continuous on this + + align:start position:0% +it's because f is continuous on this + + + align:start position:0% +it's because f is continuous on this +closing bounded interval this is + + align:start position:0% +closing bounded interval this is + + + align:start position:0% +closing bounded interval this is +something we + + align:start position:0% +something we + + + align:start position:0% +something we +proved when we were discussing + + align:start position:0% +proved when we were discussing + + + align:start position:0% +proved when we were discussing +continuity the min max theorem + + align:start position:0% +continuity the min max theorem + + + align:start position:0% +continuity the min max theorem +so + + align:start position:0% +so + + + align:start position:0% +so +let's uh let's give the + + align:start position:0% +let's uh let's give the + + + align:start position:0% +let's uh let's give the +proof um + + align:start position:0% + + + + align:start position:0% + +since f is continuous + + align:start position:0% + + + + align:start position:0% + +on a b + + align:start position:0% + + + + align:start position:0% + +f + + align:start position:0% + + + + align:start position:0% + +achieves a + + align:start position:0% +achieves a + + + align:start position:0% +achieves a +relative + + align:start position:0% +relative + + + align:start position:0% +relative +max + + align:start position:0% +max + + + align:start position:0% +max +at + + align:start position:0% +at + + + align:start position:0% +at +some point c1 + + align:start position:0% +some point c1 + + + align:start position:0% +some point c1 +and a b + + align:start position:0% +and a b + + + align:start position:0% +and a b +and + + align:start position:0% +and + + + align:start position:0% +and +relative min + + align:start position:0% +relative min + + + align:start position:0% +relative min +at + + align:start position:0% +at + + + align:start position:0% +at +c2 + + align:start position:0% + + + + align:start position:0% + +and a b + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +if there exists a x + + align:start position:0% +if there exists a x + + + align:start position:0% +if there exists a x +well so + + align:start position:0% + + + + align:start position:0% + +if of f of c one is positive + + align:start position:0% +if of f of c one is positive + + + align:start position:0% +if of f of c one is positive +then what can you say + + align:start position:0% +then what can you say + + + align:start position:0% +then what can you say +well c1 cannot be one of the endpoints + + align:start position:0% +well c1 cannot be one of the endpoints + + + align:start position:0% +well c1 cannot be one of the endpoints +because at the endpoints + + align:start position:0% +because at the endpoints + + + align:start position:0% +because at the endpoints +f of a equals f of b equals zero right + + align:start position:0% + + + + align:start position:0% + +this implies c one + + align:start position:0% +this implies c one + + + align:start position:0% +this implies c one +is in the open interval a b + + align:start position:0% +is in the open interval a b + + + align:start position:0% +is in the open interval a b +which implies by the previous theorem + + align:start position:0% +which implies by the previous theorem + + + align:start position:0% +which implies by the previous theorem +f prime of c1 + + align:start position:0% +f prime of c1 + + + align:start position:0% +f prime of c1 +equals zero + + align:start position:0% +equals zero + + + align:start position:0% +equals zero +so here you + + align:start position:0% + + + + align:start position:0% + +c equals c1 + + align:start position:0% + + + + align:start position:0% + +if i'm at the minimum now + + align:start position:0% +if i'm at the minimum now + + + align:start position:0% +if i'm at the minimum now +and this is less than zero + + align:start position:0% +and this is less than zero + + + align:start position:0% +and this is less than zero +then again + + align:start position:0% + + + + align:start position:0% + +this implies that uh + + align:start position:0% +this implies that uh + + + align:start position:0% +this implies that uh +c2 is in the open interval a b + + align:start position:0% +c2 is in the open interval a b + + + align:start position:0% +c2 is in the open interval a b +which implies since uh + + align:start position:0% +which implies since uh + + + align:start position:0% +which implies since uh +f has a + + align:start position:0% +f has a + + + align:start position:0% +f has a +minimum at c two + + align:start position:0% +minimum at c two + + + align:start position:0% +minimum at c two +f prime of c two equals zero by the + + align:start position:0% +f prime of c two equals zero by the + + + align:start position:0% +f prime of c two equals zero by the +previous theorem and therefore we could + + align:start position:0% +previous theorem and therefore we could + + + align:start position:0% +previous theorem and therefore we could +take c equals c2 + + align:start position:0% + + + + align:start position:0% + +all right + + align:start position:0% +all right + + + align:start position:0% +all right +if + + align:start position:0% +if + + + align:start position:0% +if +now this is two cases f of c one + + align:start position:0% +now this is two cases f of c one + + + align:start position:0% +now this is two cases f of c one +if either f c one is positive or f c 2 + + align:start position:0% +if either f c one is positive or f c 2 + + + align:start position:0% +if either f c one is positive or f c 2 +is less than 0 then + + align:start position:0% + + + + align:start position:0% + +we have + + align:start position:0% + + + + align:start position:0% + +the result + + align:start position:0% +the result + + + align:start position:0% +the result +if f of + + align:start position:0% +if f of + + + align:start position:0% +if f of +c 1 is less than or equal to 0 is less + + align:start position:0% +c 1 is less than or equal to 0 is less + + + align:start position:0% +c 1 is less than or equal to 0 is less +than or equal to f c + + align:start position:0% +than or equal to f c + + + align:start position:0% +than or equal to f c +now remember + + align:start position:0% +now remember + + + align:start position:0% +now remember +f achieves a max at c1 + + align:start position:0% +f achieves a max at c1 + + + align:start position:0% +f achieves a max at c1 +f achieves a min at c2 + + align:start position:0% +f achieves a min at c2 + + + align:start position:0% +f achieves a min at c2 +and therefore this should always be less + + align:start position:0% +and therefore this should always be less + + + align:start position:0% +and therefore this should always be less +than or equal to this + + align:start position:0% + + + + align:start position:0% + +if uh the max and the min + + align:start position:0% + + + + align:start position:0% + +so first off um + + align:start position:0% + + + + align:start position:0% + +and make sure i'm getting my logic + + align:start position:0% +and make sure i'm getting my logic + + + align:start position:0% +and make sure i'm getting my logic +correct here + + align:start position:0% + + + + align:start position:0% + +okay so rather than state it this way + + align:start position:0% +okay so rather than state it this way + + + align:start position:0% +okay so rather than state it this way +let's let's do it like uh + + align:start position:0% +let's let's do it like uh + + + align:start position:0% +let's let's do it like uh +let's let's + + align:start position:0% +let's let's + + + align:start position:0% +let's let's +do it like this + + align:start position:0% + + + + align:start position:0% + +so in terms of the picture here + + align:start position:0% +so in terms of the picture here + + + align:start position:0% +so in terms of the picture here +this would be c1 + + align:start position:0% + + + + align:start position:0% + +c2 where we achieve a max and a min + + align:start position:0% +c2 where we achieve a max and a min + + + align:start position:0% +c2 where we achieve a max and a min +okay then + + align:start position:0% + + + + align:start position:0% + +in the final case that + + align:start position:0% +in the final case that + + + align:start position:0% +in the final case that +f of c1 + + align:start position:0% + + + + align:start position:0% + +and + + align:start position:0% + + + + align:start position:0% + +then so this is the max + + align:start position:0% +then so this is the max + + + align:start position:0% +then so this is the max +0 is equal to + + align:start position:0% +0 is equal to + + + align:start position:0% +0 is equal to +f evaluated at a + + align:start position:0% + + + + align:start position:0% + +point then + + align:start position:0% + + + + align:start position:0% + +all right so let me go back to + + align:start position:0% +all right so let me go back to + + + align:start position:0% +all right so let me go back to +what i was going to say a minute ago so + + align:start position:0% +what i was going to say a minute ago so + + + align:start position:0% +what i was going to say a minute ago so +in the last case that + + align:start position:0% +in the last case that + + + align:start position:0% +in the last case that +f of c one is less than or equal to zero + + align:start position:0% +f of c one is less than or equal to zero + + + align:start position:0% +f of c one is less than or equal to zero +is less than f of c + + align:start position:0% +is less than f of c + + + align:start position:0% +is less than f of c +now remember this is + + align:start position:0% +now remember this is + + + align:start position:0% +now remember this is +the min + + align:start position:0% +the min + + + align:start position:0% +the min +this is + + align:start position:0% +this is + + + align:start position:0% +this is +the max of f right + + align:start position:0% +the max of f right + + + align:start position:0% +the max of f right +so this should always sit + + align:start position:0% +so this should always sit + + + align:start position:0% +so this should always sit +above + + align:start position:0% +above + + + align:start position:0% +above +f of c2 so that implies + + align:start position:0% +f of c2 so that implies + + + align:start position:0% +f of c2 so that implies +that f of c1 equals + + align:start position:0% +that f of c1 equals + + + align:start position:0% +that f of c1 equals +f of c2 + + align:start position:0% +f of c2 + + + align:start position:0% +f of c2 +and therefore the max and men equal each + + align:start position:0% +and therefore the max and men equal each + + + align:start position:0% +and therefore the max and men equal each +other + + align:start position:0% +other + + + align:start position:0% +other +right + + align:start position:0% + + + + align:start position:0% + +which implies um + + align:start position:0% + + + + align:start position:0% + +for all x and a b + + align:start position:0% +for all x and a b + + + align:start position:0% +for all x and a b +since f of c one is uh + + align:start position:0% +since f of c one is uh + + + align:start position:0% +since f of c one is uh +uh the minimum + + align:start position:0% +uh the minimum + + + align:start position:0% +uh the minimum +or f of c two is uh + + align:start position:0% + + + + align:start position:0% + +so i started off with something here + + align:start position:0% +so i started off with something here + + + align:start position:0% +so i started off with something here +there and in between which implies + + align:start position:0% +there and in between which implies + + + align:start position:0% +there and in between which implies +for all x and a b + + align:start position:0% + + + + align:start position:0% + +f of x equals f of c two + + align:start position:0% +f of x equals f of c two + + + align:start position:0% +f of x equals f of c two +so that means f is constant right + + align:start position:0% + + + + align:start position:0% + +and we know what the derivative of a + + align:start position:0% +and we know what the derivative of a + + + align:start position:0% +and we know what the derivative of a +constant function is it's just 0. + + align:start position:0% +constant function is it's just 0. + + + align:start position:0% +constant function is it's just 0. +so we could take + + align:start position:0% + + + + align:start position:0% + +say the midpoint + + align:start position:0% + + + + align:start position:0% + +and that's the end + + align:start position:0% +and that's the end + + + align:start position:0% +and that's the end +okay sorry so that i kind of fumbled + + align:start position:0% +okay sorry so that i kind of fumbled + + + align:start position:0% +okay sorry so that i kind of fumbled +through that uh + + align:start position:0% +through that uh + + + align:start position:0% +through that uh +for a minute but um + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so for any function which is zero at uh + + align:start position:0% +so for any function which is zero at uh + + + align:start position:0% +so for any function which is zero at uh +um the endpoints there has to be a point + + align:start position:0% +um the endpoints there has to be a point + + + align:start position:0% +um the endpoints there has to be a point +in between where + + align:start position:0% +in between where + + + align:start position:0% +in between where +um + + align:start position:0% +um + + + align:start position:0% +um +the function is + + align:start position:0% +the function is + + + align:start position:0% +the function is +the derivative of the function equals + + align:start position:0% +the derivative of the function equals + + + align:start position:0% +the derivative of the function equals +zero now + + align:start position:0% +zero now + + + align:start position:0% +zero now +you know + + align:start position:0% +you know + + + align:start position:0% +you know +again we should come back to + + align:start position:0% +again we should come back to + + + align:start position:0% +again we should come back to +um + + align:start position:0% +um + + + align:start position:0% +um +you know when we see a theorem we should + + align:start position:0% +you know when we see a theorem we should + + + align:start position:0% +you know when we see a theorem we should +kind of pick it apart a little bit to + + align:start position:0% +kind of pick it apart a little bit to + + + align:start position:0% +kind of pick it apart a little bit to +see what's necessary what's not + + align:start position:0% +see what's necessary what's not + + + align:start position:0% +see what's necessary what's not +um + + align:start position:0% +um + + + align:start position:0% +um +you know + + align:start position:0% +you know + + + align:start position:0% +you know +we had these two hypotheses coming in + + align:start position:0% +we had these two hypotheses coming in + + + align:start position:0% +we had these two hypotheses coming in +that the function is continuous and + + align:start position:0% +that the function is continuous and + + + align:start position:0% +that the function is continuous and +differentiable on this uh open interval + + align:start position:0% +differentiable on this uh open interval + + + align:start position:0% +differentiable on this uh open interval +a b + + align:start position:0% +a b + + + align:start position:0% +a b +um + + align:start position:0% +um + + + align:start position:0% +um +are these uh necessary so + + align:start position:0% +are these uh necessary so + + + align:start position:0% +are these uh necessary so +um + + align:start position:0% + + + + align:start position:0% + +right + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +for example let's say i have um + + align:start position:0% + + + + align:start position:0% + +the function + + align:start position:0% +the function + + + align:start position:0% +the function +if i look at the function um + + align:start position:0% +if i look at the function um + + + align:start position:0% +if i look at the function um +1 minus the absolute value of x + + align:start position:0% +1 minus the absolute value of x + + + align:start position:0% +1 minus the absolute value of x +so at -1 1 + + align:start position:0% + + + + align:start position:0% + +1. + + align:start position:0% + + + + align:start position:0% + +this is a continuous function on + + align:start position:0% + + + + align:start position:0% + +minus one one + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +and f of minus one equals f of one + + align:start position:0% +and f of minus one equals f of one + + + align:start position:0% +and f of minus one equals f of one +equals zero but there is no point where + + align:start position:0% +equals zero but there is no point where + + + align:start position:0% +equals zero but there is no point where +f prime of c equals 0. what hypothesis + + align:start position:0% +f prime of c equals 0. what hypothesis + + + align:start position:0% +f prime of c equals 0. what hypothesis +did i leave out for this function the + + align:start position:0% +did i leave out for this function the + + + align:start position:0% +did i leave out for this function the +fact that it's dif the hypothesis that + + align:start position:0% +fact that it's dif the hypothesis that + + + align:start position:0% +fact that it's dif the hypothesis that +it's differentiable at every point in + + align:start position:0% +it's differentiable at every point in + + + align:start position:0% +it's differentiable at every point in +between right this function's not + + align:start position:0% +between right this function's not + + + align:start position:0% +between right this function's not +differentiable uh + + align:start position:0% + + + + align:start position:0% + +um + + align:start position:0% +um + + + align:start position:0% +um +but there's no point where the + + align:start position:0% +but there's no point where the + + + align:start position:0% +but there's no point where the +derivative equals zero right so this + + align:start position:0% +derivative equals zero right so this + + + align:start position:0% +derivative equals zero right so this +example um you know tells you that the + + align:start position:0% +example um you know tells you that the + + + align:start position:0% +example um you know tells you that the +hypothesis that the function is + + align:start position:0% +hypothesis that the function is + + + align:start position:0% +hypothesis that the function is +um + + align:start position:0% +um + + + align:start position:0% +um +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +you know differentiable on + + align:start position:0% +you know differentiable on + + + align:start position:0% +you know differentiable on +uh + + align:start position:0% +uh + + + align:start position:0% +uh +the interval minus one one or a b is + + align:start position:0% +the interval minus one one or a b is + + + align:start position:0% +the interval minus one one or a b is +necessary for the theorem to be true + + align:start position:0% +necessary for the theorem to be true + + + align:start position:0% +necessary for the theorem to be true +okay that's what i'm getting at + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +now + + align:start position:0% +now + + + align:start position:0% +now +you know the other hypothesis that the + + align:start position:0% +you know the other hypothesis that the + + + align:start position:0% +you know the other hypothesis that the +function is continuous on the closed + + align:start position:0% +function is continuous on the closed + + + align:start position:0% +function is continuous on the closed +interval + + align:start position:0% +interval + + + align:start position:0% +interval +is also necessary + + align:start position:0% +is also necessary + + + align:start position:0% +is also necessary +let's say i look at + + align:start position:0% + + + + align:start position:0% + +and this is this is pretty easy to come + + align:start position:0% +and this is this is pretty easy to come + + + align:start position:0% +and this is this is pretty easy to come +up with a counter example if i don't + + align:start position:0% +up with a counter example if i don't + + + align:start position:0% +up with a counter example if i don't +assume that + + align:start position:0% + + + + align:start position:0% + +let's take + + align:start position:0% + + + + align:start position:0% + +let's take the function which is + + align:start position:0% + + + + align:start position:0% + +the function that's x minus 1 for x not + + align:start position:0% +the function that's x minus 1 for x not + + + align:start position:0% +the function that's x minus 1 for x not +equal to -1 and 0 + + align:start position:0% +equal to -1 and 0 + + + align:start position:0% +equal to -1 and 0 +for x equal to -1 so what does this + + align:start position:0% +for x equal to -1 so what does this + + + align:start position:0% +for x equal to -1 so what does this +function look like + + align:start position:0% + + + + align:start position:0% + +so this function here + + align:start position:0% +so this function here + + + align:start position:0% +so this function here +is + + align:start position:0% + + + + align:start position:0% + +differentiable on + + align:start position:0% +differentiable on + + + align:start position:0% +differentiable on +minus 1 1 + + align:start position:0% +minus 1 1 + + + align:start position:0% +minus 1 1 +f of minus 1 equals f of 1 + + align:start position:0% +f of minus 1 equals f of 1 + + + align:start position:0% +f of minus 1 equals f of 1 +equals 0. + + align:start position:0% +equals 0. + + + align:start position:0% +equals 0. +but again there's no point + + align:start position:0% + + + + align:start position:0% + +c + + align:start position:0% +c + + + align:start position:0% +c +n minus 1 1 + + align:start position:0% +n minus 1 1 + + + align:start position:0% +n minus 1 1 +so that + + align:start position:0% +so that + + + align:start position:0% +so that +f prime of c equals 0 + + align:start position:0% +f prime of c equals 0 + + + align:start position:0% +f prime of c equals 0 +okay + + align:start position:0% +okay + + + align:start position:0% +okay +because the derivative in between uh + + align:start position:0% +because the derivative in between uh + + + align:start position:0% +because the derivative in between uh +minus 1 1 is just 1. + + align:start position:0% +minus 1 1 is just 1. + + + align:start position:0% +minus 1 1 is just 1. +all right so + + align:start position:0% +all right so + + + align:start position:0% +all right so +both of these hypotheses + + align:start position:0% +both of these hypotheses + + + align:start position:0% +both of these hypotheses +that f is continuous on the closed + + align:start position:0% +that f is continuous on the closed + + + align:start position:0% +that f is continuous on the closed +interval and differentiable on the open + + align:start position:0% +interval and differentiable on the open + + + align:start position:0% +interval and differentiable on the open +interval + + align:start position:0% +interval + + + align:start position:0% +interval +are necessary for this theorem to be + + align:start position:0% +are necessary for this theorem to be + + + align:start position:0% +are necessary for this theorem to be +true + + align:start position:0% +true + + + align:start position:0% +true +if you drop either of those hypotheses + + align:start position:0% +if you drop either of those hypotheses + + + align:start position:0% +if you drop either of those hypotheses +then the theorem is false + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% + + + + align:start position:0% + +all right so let's rotate this picture + + align:start position:0% +all right so let's rotate this picture + + + align:start position:0% +all right so let's rotate this picture +here and arrive at the mean value + + align:start position:0% +here and arrive at the mean value + + + align:start position:0% +here and arrive at the mean value +theorem + + align:start position:0% + + + + align:start position:0% + +add f from a b to r + + align:start position:0% +add f from a b to r + + + align:start position:0% +add f from a b to r +b + + align:start position:0% +b + + + align:start position:0% +b +continuous so it's continuous on the + + align:start position:0% +continuous so it's continuous on the + + + align:start position:0% +continuous so it's continuous on the +closed interval a b + + align:start position:0% + + + + align:start position:0% + +differentiable + + align:start position:0% +differentiable + + + align:start position:0% +differentiable +on a b + + align:start position:0% + + + + align:start position:0% + +then there exists a c + + align:start position:0% +then there exists a c + + + align:start position:0% +then there exists a c +in the open interval a b + + align:start position:0% + + + + align:start position:0% + +such that + + align:start position:0% + + + + align:start position:0% + +f prime of c + + align:start position:0% +f prime of c + + + align:start position:0% +f prime of c +write it this way + + align:start position:0% + + + + align:start position:0% + +f of b minus f of a + + align:start position:0% + + + + align:start position:0% + +times b minus a + + align:start position:0% +times b minus a + + + align:start position:0% +times b minus a +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so why do i refer to it as a kind of + + align:start position:0% +so why do i refer to it as a kind of + + + align:start position:0% +so why do i refer to it as a kind of +rotated picture of uh + + align:start position:0% +rotated picture of uh + + + align:start position:0% +rotated picture of uh +and shifted kind of version of rolle's + + align:start position:0% +and shifted kind of version of rolle's + + + align:start position:0% +and shifted kind of version of rolle's +theorem + + align:start position:0% + + + + align:start position:0% + +so there's a b + + align:start position:0% +so there's a b + + + align:start position:0% +so there's a b +there's uh + + align:start position:0% +there's uh + + + align:start position:0% +there's uh +f of a f b + + align:start position:0% +f of a f b + + + align:start position:0% +f of a f b +and + + align:start position:0% + + + + align:start position:0% + +let's say that's uh how the function + + align:start position:0% +let's say that's uh how the function + + + align:start position:0% +let's say that's uh how the function +looks now + + align:start position:0% +looks now + + + align:start position:0% +looks now +the slope of the line + + align:start position:0% +the slope of the line + + + align:start position:0% +the slope of the line +connecting f of b to f of a is exactly f + + align:start position:0% +connecting f of b to f of a is exactly f + + + align:start position:0% +connecting f of b to f of a is exactly f +of b minus f of a + + align:start position:0% + + + + align:start position:0% + +okay so the slope of that line + + align:start position:0% + + + + align:start position:0% + +is f of b minus f of a + + align:start position:0% +is f of b minus f of a + + + align:start position:0% +is f of b minus f of a +and what we're stating is that there's a + + align:start position:0% +and what we're stating is that there's a + + + align:start position:0% +and what we're stating is that there's a +point + + align:start position:0% + + + + align:start position:0% + +c so that the tangent + + align:start position:0% + + + + align:start position:0% + +at that point is parallel to that line + + align:start position:0% +at that point is parallel to that line + + + align:start position:0% +at that point is parallel to that line +okay has the same slope as the line + + align:start position:0% +okay has the same slope as the line + + + align:start position:0% +okay has the same slope as the line +connecting + + align:start position:0% + + + + align:start position:0% + +f of b + + align:start position:0% +f of b + + + align:start position:0% +f of b +to f of a + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +this stem really does reduce to rolls + + align:start position:0% +this stem really does reduce to rolls + + + align:start position:0% +this stem really does reduce to rolls +theorem + + align:start position:0% +theorem + + + align:start position:0% +theorem +so + + align:start position:0% + + + + align:start position:0% + +let me define a function g from a b to r + + align:start position:0% + + + + align:start position:0% + +which satisfies the the hypotheses of + + align:start position:0% +which satisfies the the hypotheses of + + + align:start position:0% +which satisfies the the hypotheses of +rolle's theorem + + align:start position:0% +rolle's theorem + + + align:start position:0% +rolle's theorem +and will give us what we want basically + + align:start position:0% + + + + align:start position:0% + +so g of x + + align:start position:0% +so g of x + + + align:start position:0% +so g of x +equals f of x + + align:start position:0% +equals f of x + + + align:start position:0% +equals f of x +minus f of b + + align:start position:0% + + + + align:start position:0% + +plus + + align:start position:0% + + + + align:start position:0% + +f of b minus f of a + + align:start position:0% +f of b minus f of a + + + align:start position:0% +f of b minus f of a +over b minus a + + align:start position:0% +over b minus a + + + align:start position:0% +over b minus a +times + + align:start position:0% +times + + + align:start position:0% +times +b minus x + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +basically what this function g does is + + align:start position:0% +basically what this function g does is + + + align:start position:0% +basically what this function g does is +it takes + + align:start position:0% +it takes + + + align:start position:0% +it takes +uh the function now + + align:start position:0% +uh the function now + + + align:start position:0% +uh the function now +and rotates it and shifts it down so + + align:start position:0% +and rotates it and shifts it down so + + + align:start position:0% +and rotates it and shifts it down so +that f + + align:start position:0% +that f + + + align:start position:0% +that f +kind of these two points then coincide + + align:start position:0% +kind of these two points then coincide + + + align:start position:0% +kind of these two points then coincide +and give you 0. + + align:start position:0% +and give you 0. + + + align:start position:0% +and give you 0. +all right + + align:start position:0% + + + + align:start position:0% + +then + + align:start position:0% +then + + + align:start position:0% +then +g + + align:start position:0% +g + + + align:start position:0% +g +is + + align:start position:0% +is + + + align:start position:0% +is +continuous + + align:start position:0% +continuous + + + align:start position:0% +continuous +on the closed interval a b + + align:start position:0% +on the closed interval a b + + + align:start position:0% +on the closed interval a b +why because it's a sum of two continuous + + align:start position:0% +why because it's a sum of two continuous + + + align:start position:0% +why because it's a sum of two continuous +functions on a b f of x is continuous on + + align:start position:0% +functions on a b f of x is continuous on + + + align:start position:0% +functions on a b f of x is continuous on +a b on a b and this is just a constant + + align:start position:0% +a b on a b and this is just a constant + + + align:start position:0% +a b on a b and this is just a constant +that's just a constant this is a + + align:start position:0% +that's just a constant this is a + + + align:start position:0% +that's just a constant this is a +polynomial + + align:start position:0% +polynomial + + + align:start position:0% +polynomial +so g is continuous on bait on a b + + align:start position:0% +so g is continuous on bait on a b + + + align:start position:0% +so g is continuous on bait on a b +and + + align:start position:0% + + + + align:start position:0% + +differentiable on + + align:start position:0% + + + + align:start position:0% + +a b again because f is right f is + + align:start position:0% +a b again because f is right f is + + + align:start position:0% +a b again because f is right f is +differentiable on the open interval a b + + align:start position:0% +differentiable on the open interval a b + + + align:start position:0% +differentiable on the open interval a b +uh this part is differentiable + + align:start position:0% +uh this part is differentiable + + + align:start position:0% +uh this part is differentiable +everywhere so + + align:start position:0% +everywhere so + + + align:start position:0% +everywhere so +the sum of two differentiable functions + + align:start position:0% +the sum of two differentiable functions + + + align:start position:0% +the sum of two differentiable functions +is differentiable so g of x is + + align:start position:0% +is differentiable so g of x is + + + align:start position:0% +is differentiable so g of x is +differentiable on a b + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% + + + + align:start position:0% + +continuous on a b and differentiable on + + align:start position:0% +continuous on a b and differentiable on + + + align:start position:0% +continuous on a b and differentiable on +a b + + align:start position:0% + + + + align:start position:0% + +and since i said we're going to use + + align:start position:0% +and since i said we're going to use + + + align:start position:0% +and since i said we're going to use +rolls theorem let's compute g of a this + + align:start position:0% +rolls theorem let's compute g of a this + + + align:start position:0% +rolls theorem let's compute g of a this +is equal to + + align:start position:0% +is equal to + + + align:start position:0% +is equal to +f of a minus f of b + + align:start position:0% +f of a minus f of b + + + align:start position:0% +f of a minus f of b +plus + + align:start position:0% +plus + + + align:start position:0% +plus +f of b minus f of a + + align:start position:0% +f of b minus f of a + + + align:start position:0% +f of b minus f of a +over b minus a + + align:start position:0% +over b minus a + + + align:start position:0% +over b minus a +times b minus a that cancels with that + + align:start position:0% +times b minus a that cancels with that + + + align:start position:0% +times b minus a that cancels with that +minus f of b cancels with f of b + + align:start position:0% +minus f of b cancels with f of b + + + align:start position:0% +minus f of b cancels with f of b +f of a cancels with minus f of a and we + + align:start position:0% +f of a cancels with minus f of a and we + + + align:start position:0% +f of a cancels with minus f of a and we +get 0. + + align:start position:0% + + + + align:start position:0% + +then g of b + + align:start position:0% +then g of b + + + align:start position:0% +then g of b +this is even easier to see if i just + + align:start position:0% +this is even easier to see if i just + + + align:start position:0% +this is even easier to see if i just +stick this in this is f of b + + align:start position:0% +stick this in this is f of b + + + align:start position:0% +stick this in this is f of b +minus f of b + + align:start position:0% +minus f of b + + + align:start position:0% +minus f of b +plus + + align:start position:0% +plus + + + align:start position:0% +plus +f of b + + align:start position:0% +f of b + + + align:start position:0% +f of b +minus f of a + + align:start position:0% +minus f of a + + + align:start position:0% +minus f of a +over b minus a b minus b + + align:start position:0% +over b minus a b minus b + + + align:start position:0% +over b minus a b minus b +and this also equals zero okay so g of a + + align:start position:0% +and this also equals zero okay so g of a + + + align:start position:0% +and this also equals zero okay so g of a +and g of b are zero it's the function is + + align:start position:0% +and g of b are zero it's the function is + + + align:start position:0% +and g of b are zero it's the function is +continuous on the closed interval it's + + align:start position:0% +continuous on the closed interval it's + + + align:start position:0% +continuous on the closed interval it's +differentiable on the open interval and + + align:start position:0% + + + + align:start position:0% + +therefore by rolls theorem i think + + align:start position:0% +therefore by rolls theorem i think + + + align:start position:0% +therefore by rolls theorem i think +they're supposed to be some sort of + + align:start position:0% +they're supposed to be some sort of + + + align:start position:0% +they're supposed to be some sort of +accent over o but i can't + + align:start position:0% +accent over o but i can't + + + align:start position:0% +accent over o but i can't +i can't remember and i've forgotten it + + align:start position:0% +i can't remember and i've forgotten it + + + align:start position:0% +i can't remember and i've forgotten it +already um + + align:start position:0% +already um + + + align:start position:0% +already um +by roll's theorem there exists + + align:start position:0% +by roll's theorem there exists + + + align:start position:0% +by roll's theorem there exists +point c and a b + + align:start position:0% +point c and a b + + + align:start position:0% +point c and a b +such that + + align:start position:0% + + + + align:start position:0% + + + align:start position:0% + + + align:start position:0% +is equal to + + align:start position:0% +is equal to + + + align:start position:0% +is equal to +g prime of c which is equal to + + align:start position:0% + + + + align:start position:0% + +we take g and actually compute what the + + align:start position:0% +we take g and actually compute what the + + + align:start position:0% +we take g and actually compute what the +derivative is at + + align:start position:0% +derivative is at + + + align:start position:0% +derivative is at +uh + + align:start position:0% +uh + + + align:start position:0% +uh +c is equal to f prime of c + + align:start position:0% +c is equal to f prime of c + + + align:start position:0% +c is equal to f prime of c +that's a constant derivative of that is + + align:start position:0% +that's a constant derivative of that is + + + align:start position:0% +that's a constant derivative of that is +0. + + align:start position:0% +0. + + + align:start position:0% +0. +this times this the derivative of x + + align:start position:0% +this times this the derivative of x + + + align:start position:0% +this times this the derivative of x +evaluated at c just gives me minus + + align:start position:0% +evaluated at c just gives me minus + + + align:start position:0% +evaluated at c just gives me minus +f of b minus f of a + + align:start position:0% +f of b minus f of a + + + align:start position:0% +f of b minus f of a +times + + align:start position:0% +times + + + align:start position:0% +times +b minus a + + align:start position:0% + + + + align:start position:0% + +and that's it + + align:start position:0% + + + + align:start position:0% + +0 is equal to f prime of f prime of c + + align:start position:0% +0 is equal to f prime of f prime of c + + + align:start position:0% +0 is equal to f prime of f prime of c +minus what we want we move that to the + + align:start position:0% +minus what we want we move that to the + + + align:start position:0% +minus what we want we move that to the +other side multiply through by b minus a + + align:start position:0% +other side multiply through by b minus a + + + align:start position:0% +other side multiply through by b minus a +and we're done + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% + + + + align:start position:0% + +first + + align:start position:0% +first + + + align:start position:0% +first +very nice applications of the mean value + + align:start position:0% +very nice applications of the mean value + + + align:start position:0% +very nice applications of the mean value +theorem which i think you learned from + + align:start position:0% +theorem which i think you learned from + + + align:start position:0% +theorem which i think you learned from +calculus + + align:start position:0% +calculus + + + align:start position:0% +calculus +are the following + + align:start position:0% +are the following + + + align:start position:0% +are the following +[Applause] + + align:start position:0% + + + + align:start position:0% + +let f from i to r b differentiable + + align:start position:0% + + + + align:start position:0% + +meaning it's differentiable at every + + align:start position:0% +meaning it's differentiable at every + + + align:start position:0% +meaning it's differentiable at every +point + + align:start position:0% + + + + align:start position:0% + +in the interval i + + align:start position:0% +in the interval i + + + align:start position:0% +in the interval i +then we have two conclusions + + align:start position:0% +then we have two conclusions + + + align:start position:0% +then we have two conclusions +f is increasing + + align:start position:0% + + + + align:start position:0% + +meaning let me uh + + align:start position:0% +meaning let me uh + + + align:start position:0% +meaning let me uh +recall what that means for f to be + + align:start position:0% +recall what that means for f to be + + + align:start position:0% +recall what that means for f to be +increasing that means that if x is + + align:start position:0% +increasing that means that if x is + + + align:start position:0% +increasing that means that if x is +less than y + + align:start position:0% +less than y + + + align:start position:0% +less than y +this implies + + align:start position:0% +this implies + + + align:start position:0% +this implies +f of x is less than or equal to f of y + + align:start position:0% + + + + align:start position:0% + +this is equivalent to + + align:start position:0% + + + + align:start position:0% + +for all x and i + + align:start position:0% +for all x and i + + + align:start position:0% +for all x and i +f prime of x is bigger than or equal to + + align:start position:0% +f prime of x is bigger than or equal to + + + align:start position:0% +f prime of x is bigger than or equal to +zero so remember f is f prime is the + + align:start position:0% +zero so remember f is f prime is the + + + align:start position:0% +zero so remember f is f prime is the +rate of change if the rate of change is + + align:start position:0% +rate of change if the rate of change is + + + align:start position:0% +rate of change if the rate of change is +always non-negative then f has to be + + align:start position:0% +always non-negative then f has to be + + + align:start position:0% +always non-negative then f has to be +growing + + align:start position:0% +growing + + + align:start position:0% +growing +so this says + + align:start position:0% + + + + align:start position:0% + +f is decreasing + + align:start position:0% + + + + align:start position:0% + +meaning x + + align:start position:0% +meaning x + + + align:start position:0% +meaning x +less than y implies + + align:start position:0% +less than y implies + + + align:start position:0% +less than y implies +f of x is bigger than or equal to f of y + + align:start position:0% +f of x is bigger than or equal to f of y + + + align:start position:0% +f of x is bigger than or equal to f of y +this is equivalent to + + align:start position:0% +this is equivalent to + + + align:start position:0% +this is equivalent to +since a function is increasing if and + + align:start position:0% +since a function is increasing if and + + + align:start position:0% +since a function is increasing if and +only if minus f is decreasing this + + align:start position:0% +only if minus f is decreasing this + + + align:start position:0% +only if minus f is decreasing this +inequality should flip + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +so i'm going to do + + align:start position:0% +so i'm going to do + + + align:start position:0% +so i'm going to do +increasing decreasing follows from + + align:start position:0% +increasing decreasing follows from + + + align:start position:0% +increasing decreasing follows from +number one by taking minus f okay + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +um + + align:start position:0% +um + + + align:start position:0% +um +how much time do i have okay i still + + align:start position:0% +how much time do i have okay i still + + + align:start position:0% +how much time do i have okay i still +have time + + align:start position:0% + + + + align:start position:0% + +so suppose first that + + align:start position:0% + + + + align:start position:0% + +f prime of x is always non-negative + + align:start position:0% + + + + align:start position:0% + +let + + align:start position:0% +let + + + align:start position:0% +let +a b + + align:start position:0% +a b + + + align:start position:0% +a b +be in + + align:start position:0% +be in + + + align:start position:0% +be in +i + + align:start position:0% + + + + align:start position:0% + +ah + + align:start position:0% +ah + + + align:start position:0% +ah +excuse me + + align:start position:0% + + + + align:start position:0% + +we now want to show f of a is less than + + align:start position:0% +we now want to show f of a is less than + + + align:start position:0% +we now want to show f of a is less than +or equal to f of b + + align:start position:0% + + + + align:start position:0% + +then f + + align:start position:0% +then f + + + align:start position:0% +then f +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +is continuous on this smaller interval a + + align:start position:0% +is continuous on this smaller interval a + + + align:start position:0% +is continuous on this smaller interval a +b why because f is differentiable at + + align:start position:0% +b why because f is differentiable at + + + align:start position:0% +b why because f is differentiable at +every point in i and therefore it is + + align:start position:0% +every point in i and therefore it is + + + align:start position:0% +every point in i and therefore it is +um + + align:start position:0% +um + + + align:start position:0% +um +continuous at every point and i so in + + align:start position:0% +continuous at every point and i so in + + + align:start position:0% +continuous at every point and i so in +particular on this smaller interval + + align:start position:0% + + + + align:start position:0% + +and differentiable + + align:start position:0% + + + + align:start position:0% + +on a b which implies + + align:start position:0% + + + + align:start position:0% + +there exists a c + + align:start position:0% +there exists a c + + + align:start position:0% +there exists a c +in a b + + align:start position:0% +in a b + + + align:start position:0% +in a b +so by the mean value theorem + + align:start position:0% + + + + align:start position:0% + +such that f of b + + align:start position:0% +such that f of b + + + align:start position:0% +such that f of b +minus f of a + + align:start position:0% +minus f of a + + + align:start position:0% +minus f of a +equals f prime of c + + align:start position:0% +equals f prime of c + + + align:start position:0% +equals f prime of c +times b minus a and now since the + + align:start position:0% +times b minus a and now since the + + + align:start position:0% +times b minus a and now since the +derivative is always non-negative and b + + align:start position:0% +derivative is always non-negative and b + + + align:start position:0% +derivative is always non-negative and b +minus a is positive this is bigger than + + align:start position:0% +minus a is positive this is bigger than + + + align:start position:0% +minus a is positive this is bigger than +or equal to zero + + align:start position:0% +or equal to zero + + + align:start position:0% +or equal to zero +i.e + + align:start position:0% +i.e + + + align:start position:0% +i.e +f of b minus f of a is bigger than or + + align:start position:0% +f of b minus f of a is bigger than or + + + align:start position:0% +f of b minus f of a is bigger than or +equal to zero + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so we've proven one direction we've + + align:start position:0% +so we've proven one direction we've + + + align:start position:0% +so we've proven one direction we've +proven that + + align:start position:0% +proven that + + + align:start position:0% +proven that +if you like + + align:start position:0% + + + + align:start position:0% + +um + + align:start position:0% +um + + + align:start position:0% +um +that + + align:start position:0% +that + + + align:start position:0% +that +the function's derivative being + + align:start position:0% +the function's derivative being + + + align:start position:0% +the function's derivative being +non-negative implies that the function + + align:start position:0% +non-negative implies that the function + + + align:start position:0% +non-negative implies that the function +is increasing + + align:start position:0% +is increasing + + + align:start position:0% +is increasing +so now let's prove the opposite + + align:start position:0% +so now let's prove the opposite + + + align:start position:0% +so now let's prove the opposite +direction + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +suppose f is increasing + + align:start position:0% + + + + align:start position:0% + +and c is an i + + align:start position:0% + + + + align:start position:0% + +let x in be a sequence + + align:start position:0% + + + + align:start position:0% + +and i + + align:start position:0% +and i + + + align:start position:0% +and i +such that + + align:start position:0% +such that + + + align:start position:0% +such that +xn converges to c + + align:start position:0% +xn converges to c + + + align:start position:0% +xn converges to c +and + + align:start position:0% +and + + + align:start position:0% +and +one of two things holds + + align:start position:0% + + + + align:start position:0% + +and either + + align:start position:0% +and either + + + align:start position:0% +and either +[Applause] + + align:start position:0% + + + + align:start position:0% + +say a + + align:start position:0% + + + + align:start position:0% + +for all n x n is less than c or b + + align:start position:0% +for all n x n is less than c or b + + + align:start position:0% +for all n x n is less than c or b +for all n x n is bigger than c now we + + align:start position:0% +for all n x n is bigger than c now we + + + align:start position:0% +for all n x n is bigger than c now we +can always find such a sequence given a + + align:start position:0% +can always find such a sequence given a + + + align:start position:0% +can always find such a sequence given a +point c and the interval i so + + align:start position:0% +point c and the interval i so + + + align:start position:0% +point c and the interval i so +um + + align:start position:0% +um + + + align:start position:0% +um +you know if we're + + align:start position:0% +you know if we're + + + align:start position:0% +you know if we're +if i + + align:start position:0% +if i + + + align:start position:0% +if i +so let's say + + align:start position:0% + + + + align:start position:0% + +let's say it's a closed interval + + align:start position:0% +let's say it's a closed interval + + + align:start position:0% +let's say it's a closed interval +and c is in + + align:start position:0% +and c is in + + + align:start position:0% +and c is in +here then we can find a sequence x n + + align:start position:0% +here then we can find a sequence x n + + + align:start position:0% +here then we can find a sequence x n +converging to c + + align:start position:0% +converging to c + + + align:start position:0% +converging to c +you know approaching c from the left + + align:start position:0% +you know approaching c from the left + + + align:start position:0% +you know approaching c from the left +yeah + + align:start position:0% +yeah + + + align:start position:0% +yeah +if c is one of the endpoints then we can + + align:start position:0% +if c is one of the endpoints then we can + + + align:start position:0% +if c is one of the endpoints then we can +find a sequence from i approaching c + + align:start position:0% +find a sequence from i approaching c + + + align:start position:0% +find a sequence from i approaching c +from the right that's b + + align:start position:0% +from the right that's b + + + align:start position:0% +from the right that's b +right and the same thing if c is over + + align:start position:0% +right and the same thing if c is over + + + align:start position:0% +right and the same thing if c is over +here we can find a sequence approaching + + align:start position:0% +here we can find a sequence approaching + + + align:start position:0% +here we can find a sequence approaching +c + + align:start position:0% +c + + + align:start position:0% +c +strictly from the left + + align:start position:0% +strictly from the left + + + align:start position:0% +strictly from the left +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so there always exists + + align:start position:0% +so there always exists + + + align:start position:0% +so there always exists +such a sequence + + align:start position:0% + + + + align:start position:0% + +always exist + + align:start position:0% + + + + align:start position:0% + +and this is because + + align:start position:0% + + + + align:start position:0% + +i is an interval + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and + + align:start position:0% +and + + + align:start position:0% +and +if the sequence satisfies uh case a + + align:start position:0% +if the sequence satisfies uh case a + + + align:start position:0% +if the sequence satisfies uh case a +and we look at f prime then uh + + align:start position:0% + + + + align:start position:0% + +we get that f of + + align:start position:0% +we get that f of + + + align:start position:0% +we get that f of +x n is less than or equal to f of c + + align:start position:0% +x n is less than or equal to f of c + + + align:start position:0% +x n is less than or equal to f of c +for all n + + align:start position:0% + + + + align:start position:0% + +and let me in fact write this a little + + align:start position:0% +and let me in fact write this a little + + + align:start position:0% +and let me in fact write this a little +bit differently + + align:start position:0% +bit differently + + + align:start position:0% +bit differently +since so here we're using that f is + + align:start position:0% +since so here we're using that f is + + + align:start position:0% +since so here we're using that f is +increasing + + align:start position:0% + + + + align:start position:0% + +since f is increasing + + align:start position:0% + + + + align:start position:0% + +which implies for all n + + align:start position:0% +which implies for all n + + + align:start position:0% +which implies for all n +f of x n minus f of + + align:start position:0% +f of x n minus f of + + + align:start position:0% +f of x n minus f of +c + + align:start position:0% +c + + + align:start position:0% +c +over x sub n + + align:start position:0% +over x sub n + + + align:start position:0% +over x sub n +minus c + + align:start position:0% +minus c + + + align:start position:0% +minus c +now + + align:start position:0% +now + + + align:start position:0% +now +this thing on top is negative x n uh is + + align:start position:0% +this thing on top is negative x n uh is + + + align:start position:0% +this thing on top is negative x n uh is +less than c + + align:start position:0% +less than c + + + align:start position:0% +less than c +so this thing on the bottom is also + + align:start position:0% +so this thing on the bottom is also + + + align:start position:0% +so this thing on the bottom is also +negative + + align:start position:0% + + + + align:start position:0% + +and therefore this thing is + + align:start position:0% +and therefore this thing is + + + align:start position:0% +and therefore this thing is +positive not negative i mean + + align:start position:0% +positive not negative i mean + + + align:start position:0% +positive not negative i mean +therefore the limit must also be + + align:start position:0% +therefore the limit must also be + + + align:start position:0% +therefore the limit must also be +non-negative + + align:start position:0% + + + + align:start position:0% + +but that limit is just the derivative + + align:start position:0% +but that limit is just the derivative + + + align:start position:0% +but that limit is just the derivative +evaluated at c + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and case b is kind of similar + + align:start position:0% +and case b is kind of similar + + + align:start position:0% +and case b is kind of similar +i mean not kind of it is + + align:start position:0% + + + + align:start position:0% + +in case b + + align:start position:0% +in case b + + + align:start position:0% +in case b +we get that + + align:start position:0% +we get that + + + align:start position:0% +we get that +for all n + + align:start position:0% +for all n + + + align:start position:0% +for all n +f of x n now since x ends to the right + + align:start position:0% +f of x n now since x ends to the right + + + align:start position:0% +f of x n now since x ends to the right +of c + + align:start position:0% +of c + + + align:start position:0% +of c +um + + align:start position:0% + + + + align:start position:0% + +let me write it this way + + align:start position:0% + + + + align:start position:0% + +this minus f of c is bigger than or + + align:start position:0% +this minus f of c is bigger than or + + + align:start position:0% +this minus f of c is bigger than or +equal to 0 + + align:start position:0% +equal to 0 + + + align:start position:0% +equal to 0 +which implies that + + align:start position:0% + + + + align:start position:0% + +f prime of c which is the limit as n + + align:start position:0% +f prime of c which is the limit as n + + + align:start position:0% +f prime of c which is the limit as n +goes to infinity of f of + + align:start position:0% +goes to infinity of f of + + + align:start position:0% +goes to infinity of f of +x n minus + + align:start position:0% +x n minus + + + align:start position:0% +x n minus +f of c over x n minus c + + align:start position:0% +f of c over x n minus c + + + align:start position:0% +f of c over x n minus c +what's on top is non-negative and what's + + align:start position:0% +what's on top is non-negative and what's + + + align:start position:0% +what's on top is non-negative and what's +on bottom is non-negative because x n is + + align:start position:0% +on bottom is non-negative because x n is + + + align:start position:0% +on bottom is non-negative because x n is +bigger than c + + align:start position:0% +bigger than c + + + align:start position:0% +bigger than c +so + + align:start position:0% +so + + + align:start position:0% +so +bigger than zero bigger than zero + + align:start position:0% +bigger than zero bigger than zero + + + align:start position:0% +bigger than zero bigger than zero +bigger than 0. + + align:start position:0% +bigger than 0. + + + align:start position:0% +bigger than 0. +so in either k that's so + + align:start position:0% + + + + align:start position:0% + +thus in either case we get that f prime + + align:start position:0% +thus in either case we get that f prime + + + align:start position:0% +thus in either case we get that f prime +of c is bigger than or equal to 0. + + align:start position:0% + + + + align:start position:0% + +all right + + align:start position:0% +all right + + + align:start position:0% +all right +and therefore we've proven that the + + align:start position:0% +and therefore we've proven that the + + + align:start position:0% +and therefore we've proven that the +derivative is always non-negative + + align:start position:0% +derivative is always non-negative + + + align:start position:0% +derivative is always non-negative +so that's uh + + align:start position:0% +so that's uh + + + align:start position:0% +so that's uh +one and two + + align:start position:0% + + + + align:start position:0% + +f is + + align:start position:0% + + + + align:start position:0% + +decreasing + + align:start position:0% +decreasing + + + align:start position:0% +decreasing +if and only if the function minus f + + align:start position:0% + + + + align:start position:0% + +is increasing which by what we've done + + align:start position:0% +is increasing which by what we've done + + + align:start position:0% +is increasing which by what we've done +from part one + + align:start position:0% +from part one + + + align:start position:0% +from part one +is if and only if minus f prime of x + + align:start position:0% +is if and only if minus f prime of x + + + align:start position:0% +is if and only if minus f prime of x +is bigger than or equal to zero for all + + align:start position:0% +is bigger than or equal to zero for all + + + align:start position:0% +is bigger than or equal to zero for all +x + + align:start position:0% +x + + + align:start position:0% +x +and i + + align:start position:0% +and i + + + align:start position:0% +and i +and then multiplying through by minus + + align:start position:0% +and then multiplying through by minus + + + align:start position:0% +and then multiplying through by minus +by this + + align:start position:0% +by this + + + align:start position:0% +by this +minus one + + align:start position:0% + + + + align:start position:0% + +gives me number two + + align:start position:0% +gives me number two + + + align:start position:0% +gives me number two +all right + + align:start position:0% + + + + align:start position:0% + +and so + + align:start position:0% +and so + + + align:start position:0% +and so +let me make one last uh + + align:start position:0% +let me make one last uh + + + align:start position:0% +let me make one last uh +i know it's tabuta right on the back uh + + align:start position:0% +i know it's tabuta right on the back uh + + + align:start position:0% +i know it's tabuta right on the back uh +part but i'm gonna do it anyways + + align:start position:0% +part but i'm gonna do it anyways + + + align:start position:0% +part but i'm gonna do it anyways +we have the very simple theorem which + + align:start position:0% +we have the very simple theorem which + + + align:start position:0% +we have the very simple theorem which +now follow follows + + align:start position:0% + + + + align:start position:0% + +let f from ida r + + align:start position:0% +let f from ida r + + + align:start position:0% +let f from ida r +be + + align:start position:0% + + + + align:start position:0% + +differentiable + + align:start position:0% + + + + align:start position:0% + +then + + align:start position:0% + + + + align:start position:0% + +f is constant + + align:start position:0% +f is constant + + + align:start position:0% +f is constant +so f of + + align:start position:0% +so f of + + + align:start position:0% +so f of +x equals f of y for all x and y and i + + align:start position:0% +x equals f of y for all x and y and i + + + align:start position:0% +x equals f of y for all x and y and i +if and only if + + align:start position:0% + + + + align:start position:0% + +the derivative is identically zero + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +um + + align:start position:0% + + + + align:start position:0% + +is constant if and only if + + align:start position:0% +is constant if and only if + + + align:start position:0% +is constant if and only if +f is + + align:start position:0% + + + + align:start position:0% + +both increasing + + align:start position:0% + + + + align:start position:0% + +and decreasing + + align:start position:0% + + + + align:start position:0% + +right + + align:start position:0% + + + + align:start position:0% + +because it satisfies the equality sign + + align:start position:0% +because it satisfies the equality sign + + + align:start position:0% +because it satisfies the equality sign +in both of those + + align:start position:0% +in both of those + + + align:start position:0% +in both of those +and by what we've done + + align:start position:0% + + + + align:start position:0% + +now for all this means for all x and i + + align:start position:0% +now for all this means for all x and i + + + align:start position:0% +now for all this means for all x and i +f prime of x is bigger than or equal to + + align:start position:0% +f prime of x is bigger than or equal to + + + align:start position:0% +f prime of x is bigger than or equal to +zero and + + align:start position:0% + + + + align:start position:0% + +that's for the increasing part f prime + + align:start position:0% +that's for the increasing part f prime + + + align:start position:0% +that's for the increasing part f prime +of x is less than or equal to zero + + align:start position:0% + + + + align:start position:0% + +and therefore + + align:start position:0% + + + + align:start position:0% + +f prime of x uh this is equivalent to f + + align:start position:0% +f prime of x uh this is equivalent to f + + + align:start position:0% +f prime of x uh this is equivalent to f +prime of x equals zero + + align:start position:0% + + + + align:start position:0% + +all right + + align:start position:0% + + + + align:start position:0% + +okay so we'll stop there \ No newline at end of file diff --git a/VCOrx2jEKXk.txt b/VCOrx2jEKXk.txt new file mode 100644 index 0000000000000000000000000000000000000000..9336a1ebfbd404af4788fb71c58cff7f37e597c4 --- /dev/null +++ b/VCOrx2jEKXk.txt @@ -0,0 +1,10571 @@ +align:start position:0% + +Okay. So remember that projection theory + + align:start position:0% + + + + align:start position:0% + +works differently over uh if you look in + + align:start position:0% +works differently over uh if you look in + + + align:start position:0% +works differently over uh if you look in +finite fields it works differently over + + align:start position:0% +finite fields it works differently over + + + align:start position:0% +finite fields it works differently over +a prime field or a notp prime field. And + + align:start position:0% +a prime field or a notp prime field. And + + + align:start position:0% +a prime field or a notp prime field. And +here was the key example. + + align:start position:0% + + + + align:start position:0% + +Um, so we're going to do projection + + align:start position:0% +Um, so we're going to do projection + + + align:start position:0% +Um, so we're going to do projection +theory in FQ and Q is P ^2 and our set + + align:start position:0% +theory in FQ and Q is P ^2 and our set + + + align:start position:0% +theory in FQ and Q is P ^2 and our set +of points is going to be FP^2 which is a + + align:start position:0% +of points is going to be FP^2 which is a + + + align:start position:0% +of points is going to be FP^2 which is a +subset of FQ ^2 and our set of + + align:start position:0% +subset of FQ ^2 and our set of + + + align:start position:0% +subset of FQ ^2 and our set of +directions is going to be FP which is a + + align:start position:0% +directions is going to be FP which is a + + + align:start position:0% +directions is going to be FP which is a +subset of FQ. So remember that uh if + + align:start position:0% +subset of FQ. So remember that uh if + + + align:start position:0% +subset of FQ. So remember that uh if +theta is in fq then pi theta is going to + + align:start position:0% +theta is in fq then pi theta is going to + + + align:start position:0% +theta is in fq then pi theta is going to +be a projection a linear map from fq ^2 + + align:start position:0% +be a projection a linear map from fq ^2 + + + align:start position:0% +be a projection a linear map from fq ^2 +to fq + + align:start position:0% +to fq + + + align:start position:0% +to fq +which is given by pi theta of x1 x2 is + + align:start position:0% +which is given by pi theta of x1 x2 is + + + align:start position:0% +which is given by pi theta of x1 x2 is +x1 + theta x2. + + align:start position:0% +x1 + theta x2. + + + align:start position:0% +x1 + theta x2. +So this is our set of directions + + align:start position:0% +So this is our set of directions + + + align:start position:0% +So this is our set of directions +and then s which is the maximum size of + + align:start position:0% +and then s which is the maximum size of + + + align:start position:0% +and then s which is the maximum size of +the projection of x over all these + + align:start position:0% +the projection of x over all these + + + align:start position:0% +the projection of x over all these +directions + + align:start position:0% +directions + + + align:start position:0% +directions +um is uh is is p um because pi theta of + + align:start position:0% +um is uh is is p um because pi theta of + + + align:start position:0% +um is uh is is p um because pi theta of +x is just fp + + align:start position:0% +x is just fp + + + align:start position:0% +x is just fp +uh for theta and d. + + align:start position:0% + + + + align:start position:0% + +Okay. So if you uh just write down the + + align:start position:0% +Okay. So if you uh just write down the + + + align:start position:0% +Okay. So if you uh just write down the +sizes of all the things in this + + align:start position:0% +sizes of all the things in this + + + align:start position:0% +sizes of all the things in this +important example, x is p ^2 which is q + + align:start position:0% +important example, x is p ^2 which is q + + + align:start position:0% +important example, x is p ^2 which is q +and s and d are p which is q to the + + align:start position:0% +and s and d are p which is q to the + + + align:start position:0% +and s and d are p which is q to the +half. So in in particular notice that + + align:start position:0% +half. So in in particular notice that + + + align:start position:0% +half. So in in particular notice that +the size of each projection is the + + align:start position:0% +the size of each projection is the + + + align:start position:0% +the size of each projection is the +square root of the size of the set. + + align:start position:0% + + + + align:start position:0% + +Okay. Um so + + align:start position:0% +Okay. Um so + + + align:start position:0% +Okay. Um so +so nothing like this is supposed to + + align:start position:0% +so nothing like this is supposed to + + + align:start position:0% +so nothing like this is supposed to +happen over FP and there's a hard open + + align:start position:0% +happen over FP and there's a hard open + + + align:start position:0% +happen over FP and there's a hard open +conjecture that um that gives bounds + + align:start position:0% +conjecture that um that gives bounds + + + align:start position:0% +conjecture that um that gives bounds +that are much stronger than this + + align:start position:0% +that are much stronger than this + + + align:start position:0% +that are much stronger than this +example. Um but the techniques that + + align:start position:0% +example. Um but the techniques that + + + align:start position:0% +example. Um but the techniques that +we've talked about for most of the class + + align:start position:0% +we've talked about for most of the class + + + align:start position:0% +we've talked about for most of the class +do not depend on the field. So the + + align:start position:0% +do not depend on the field. So the + + + align:start position:0% +do not depend on the field. So the +double counting does not distinguish + + align:start position:0% +double counting does not distinguish + + + align:start position:0% +double counting does not distinguish +prime fields from not prime fields and + + align:start position:0% +prime fields from not prime fields and + + + align:start position:0% +prime fields from not prime fields and +the 4A method does not distinguish prime + + align:start position:0% +the 4A method does not distinguish prime + + + align:start position:0% +the 4A method does not distinguish prime +fields from not prime fields. + + align:start position:0% +fields from not prime fields. + + + align:start position:0% +fields from not prime fields. +Um the summer ready trotder theorem + + align:start position:0% +Um the summer ready trotder theorem + + + align:start position:0% +Um the summer ready trotder theorem +proves that this numerology cannot + + align:start position:0% +proves that this numerology cannot + + + align:start position:0% +proves that this numerology cannot +happen for a set of points in R2. Um but + + align:start position:0% +happen for a set of points in R2. Um but + + + align:start position:0% +happen for a set of points in R2. Um but +the proof has the proof is very + + align:start position:0% +the proof has the proof is very + + + align:start position:0% +the proof has the proof is very +important but it has some limitations in + + align:start position:0% +important but it has some limitations in + + + align:start position:0% +important but it has some limitations in +how it could apply. It certainly won't + + align:start position:0% +how it could apply. It certainly won't + + + align:start position:0% +how it could apply. It certainly won't +apply over FP. Um and it also doesn't + + align:start position:0% +apply over FP. Um and it also doesn't + + + align:start position:0% +apply over FP. Um and it also doesn't +seem to help very much from the point of + + align:start position:0% +seem to help very much from the point of + + + align:start position:0% +seem to help very much from the point of +view of uh sets of balls in R2 with some + + align:start position:0% +view of uh sets of balls in R2 with some + + + align:start position:0% +view of uh sets of balls in R2 with some +kind of spacing condition. It depends + + align:start position:0% +kind of spacing condition. It depends + + + align:start position:0% +kind of spacing condition. It depends +what spacing condition but for the most + + align:start position:0% +what spacing condition but for the most + + + align:start position:0% +what spacing condition but for the most +interesting spacing condition it doesn't + + align:start position:0% +interesting spacing condition it doesn't + + + align:start position:0% +interesting spacing condition it doesn't +help very much. + + align:start position:0% +help very much. + + + align:start position:0% +help very much. +Okay. Nevertheless, we know that this + + align:start position:0% +Okay. Nevertheless, we know that this + + + align:start position:0% +Okay. Nevertheless, we know that this +cannot happen over finite fields + + align:start position:0% + + + + align:start position:0% + +and the main theorem that we'll so this + + align:start position:0% +and the main theorem that we'll so this + + + align:start position:0% +and the main theorem that we'll so this +week we will prove a theorem that says + + align:start position:0% +week we will prove a theorem that says + + + align:start position:0% +week we will prove a theorem that says +that this cannot happen. So this is the + + align:start position:0% +that this cannot happen. So this is the + + + align:start position:0% +that this cannot happen. So this is the +theorem of Ban Kats and Tao. + + align:start position:0% + + + + align:start position:0% + +So again cat's tow projection theorem. + + align:start position:0% +So again cat's tow projection theorem. + + + align:start position:0% +So again cat's tow projection theorem. +Okay it says the following thing. So if + + align:start position:0% +Okay it says the following thing. So if + + + align:start position:0% +Okay it says the following thing. So if +we have x in fp^2 + + align:start position:0% +we have x in fp^2 + + + align:start position:0% +we have x in fp^2 +and let's say that the size of x is p to + + align:start position:0% +and let's say that the size of x is p to + + + align:start position:0% +and let's say that the size of x is p to +the s where s is uh somewhere between + + align:start position:0% +the s where s is uh somewhere between + + + align:start position:0% +the s where s is uh somewhere between +zero and two. + + align:start position:0% +zero and two. + + + align:start position:0% +zero and two. +Okay. And then we have a set of + + align:start position:0% +Okay. And then we have a set of + + + align:start position:0% +Okay. And then we have a set of +directions + + align:start position:0% +directions + + + align:start position:0% +directions +in FP + + align:start position:0% +in FP + + + align:start position:0% +in FP +and the set of directions will be p to + + align:start position:0% +and the set of directions will be p to + + + align:start position:0% +and the set of directions will be p to +the t and t is uh bigger than zero. + + align:start position:0% + + + + align:start position:0% + +Okay. So then if you look at the maximum + + align:start position:0% +Okay. So then if you look at the maximum + + + align:start position:0% +Okay. So then if you look at the maximum +size of a projection, + + align:start position:0% +size of a projection, + + + align:start position:0% +size of a projection, +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +it's significantly bigger than half of + + align:start position:0% +it's significantly bigger than half of + + + align:start position:0% +it's significantly bigger than half of +the the square root of the of the size + + align:start position:0% +the the square root of the of the size + + + align:start position:0% +the the square root of the of the size +of of X. So this is bigger than P to the + + align:start position:0% +of of X. So this is bigger than P to the + + + align:start position:0% +of of X. So this is bigger than P to the +S over 2 plus epsilon + + align:start position:0% + + + + align:start position:0% + +where this epsilon only depends on S and + + align:start position:0% +where this epsilon only depends on S and + + + align:start position:0% +where this epsilon only depends on S and +T. + + align:start position:0% +T. + + + align:start position:0% +T. +It's bigger than zero. + + align:start position:0% + + + + align:start position:0% + +Okay. Um, so some remarks about the + + align:start position:0% +Okay. Um, so some remarks about the + + + align:start position:0% +Okay. Um, so some remarks about the +epsilon. It's it's an explicit function. + + align:start position:0% +epsilon. It's it's an explicit function. + + + align:start position:0% +epsilon. It's it's an explicit function. +I just don't write it down because it's + + align:start position:0% +I just don't write it down because it's + + + align:start position:0% +I just don't write it down because it's +a little bit messy. For example, it's + + align:start position:0% +a little bit messy. For example, it's + + + align:start position:0% +a little bit messy. For example, it's +continuous. It's not that hard to write + + align:start position:0% +continuous. It's not that hard to write + + + align:start position:0% +continuous. It's not that hard to write +it down, but it is also pretty small. + + align:start position:0% +it down, but it is also pretty small. + + + align:start position:0% +it down, but it is also pretty small. +Pretty disappointingly small. + + align:start position:0% +Pretty disappointingly small. + + + align:start position:0% +Pretty disappointingly small. +Okay. + + align:start position:0% +Okay. + + + align:start position:0% +Okay. +Um + + align:start position:0% +Um + + + align:start position:0% +Um +there's also something called Bans's + + align:start position:0% +there's also something called Bans's + + + align:start position:0% +there's also something called Bans's +projection theorem which is what publish + + align:start position:0% +projection theorem which is what publish + + + align:start position:0% +projection theorem which is what publish +MKin is going to talk about today which + + align:start position:0% +MKin is going to talk about today which + + + align:start position:0% +MKin is going to talk about today which +is the analog of this over the in the + + align:start position:0% +is the analog of this over the in the + + + align:start position:0% +is the analog of this over the in the +setting of the real of balls in R2. + + align:start position:0% +setting of the real of balls in R2. + + + align:start position:0% +setting of the real of balls in R2. +Um so there's an analog of this example + + align:start position:0% +Um so there's an analog of this example + + + align:start position:0% +Um so there's an analog of this example +using C2 instead of R2 and then BN's + + align:start position:0% +using C2 instead of R2 and then BN's + + + align:start position:0% +using C2 instead of R2 and then BN's +projection theorem is the analog of this + + align:start position:0% +projection theorem is the analog of this + + + align:start position:0% +projection theorem is the analog of this +theorem that rules out that example. + + align:start position:0% +theorem that rules out that example. + + + align:start position:0% +theorem that rules out that example. +So + + align:start position:0% + + + + align:start position:0% + +this is an analogous theorem + + align:start position:0% + + + + align:start position:0% + +for balls and art. + + align:start position:0% +for balls and art. + + + align:start position:0% +for balls and art. +Okay. And these two theorems in spite of + + align:start position:0% +Okay. And these two theorems in spite of + + + align:start position:0% +Okay. And these two theorems in spite of +the fact that this epsilon is very small + + align:start position:0% +the fact that this epsilon is very small + + + align:start position:0% +the fact that this epsilon is very small +are very important sort of landmark + + align:start position:0% +are very important sort of landmark + + + align:start position:0% +are very important sort of landmark +results in the field of projection + + align:start position:0% +results in the field of projection + + + align:start position:0% +results in the field of projection +theory and they play a key role in many + + align:start position:0% +theory and they play a key role in many + + + align:start position:0% +theory and they play a key role in many +applications. Um uh this ban projection + + align:start position:0% +applications. Um uh this ban projection + + + align:start position:0% +applications. Um uh this ban projection +theorem it plays a key role in getting + + align:start position:0% +theorem it plays a key role in getting + + + align:start position:0% +theorem it plays a key role in getting +the sharp projection estimates in R2 the + + align:start position:0% +the sharp projection estimates in R2 the + + + align:start position:0% +the sharp projection estimates in R2 the +recent work uh that publish mkin and + + align:start position:0% +recent work uh that publish mkin and + + + align:start position:0% +recent work uh that publish mkin and +others were involved in. Um this banan + + align:start position:0% +others were involved in. Um this banan + + + align:start position:0% +others were involved in. Um this banan +projection theorem also plays an + + align:start position:0% +projection theorem also plays an + + + align:start position:0% +projection theorem also plays an +important role in the solution of the ka + + align:start position:0% +important role in the solution of the ka + + + align:start position:0% +important role in the solution of the ka +problem. + + align:start position:0% +problem. + + + align:start position:0% +problem. +Um and this finite field projection + + align:start position:0% +Um and this finite field projection + + + align:start position:0% +Um and this finite field projection +theorem as well as this one have some + + align:start position:0% +theorem as well as this one have some + + + align:start position:0% +theorem as well as this one have some +have a important role in some + + align:start position:0% +have a important role in some + + + align:start position:0% +have a important role in some +interesting applications about um how + + align:start position:0% +interesting applications about um how + + + align:start position:0% +interesting applications about um how +fast different processes mix. Like if + + align:start position:0% +fast different processes mix. Like if + + + align:start position:0% +fast different processes mix. Like if +you take some generators of a finite + + align:start position:0% +you take some generators of a finite + + + align:start position:0% +you take some generators of a finite +group like SL2 over FP + + align:start position:0% +group like SL2 over FP + + + align:start position:0% +group like SL2 over FP +um and then they make a random walk. How + + align:start position:0% +um and then they make a random walk. How + + + align:start position:0% +um and then they make a random walk. How +fast does this random walk become evenly + + align:start position:0% +fast does this random walk become evenly + + + align:start position:0% +fast does this random walk become evenly +distributed in SL2FP? + + align:start position:0% +distributed in SL2FP? + + + align:start position:0% +distributed in SL2FP? +This is an important ingredient in + + align:start position:0% +This is an important ingredient in + + + align:start position:0% +This is an important ingredient in +studying that. + + align:start position:0% +studying that. + + + align:start position:0% +studying that. +Okay. Um so okay. So in spite of the + + align:start position:0% +Okay. Um so okay. So in spite of the + + + align:start position:0% +Okay. Um so okay. So in spite of the +fact that the epsilon is small, these + + align:start position:0% +fact that the epsilon is small, these + + + align:start position:0% +fact that the epsilon is small, these +theorems are are very important and + + align:start position:0% +theorems are are very important and + + + align:start position:0% +theorems are are very important and +they're also qualitatively different + + align:start position:0% +they're also qualitatively different + + + align:start position:0% +they're also qualitatively different +from the other theorems because they're + + align:start position:0% +from the other theorems because they're + + + align:start position:0% +from the other theorems because they're +sensitive to what kind of field we're + + align:start position:0% +sensitive to what kind of field we're + + + align:start position:0% +sensitive to what kind of field we're +working. Yeah. + + align:start position:0% +working. Yeah. + + + align:start position:0% +working. Yeah. +>> What is the analog of P for ball or R2? + + align:start position:0% +>> What is the analog of P for ball or R2? + + + align:start position:0% +>> What is the analog of P for ball or R2? +>> The analog of P. So we would have uh the + + align:start position:0% +>> The analog of P. So we would have uh the + + + align:start position:0% +>> The analog of P. So we would have uh the +setting would be you'd have unit balls + + align:start position:0% +setting would be you'd have unit balls + + + align:start position:0% +setting would be you'd have unit balls +and a ball of radius r and r is the + + align:start position:0% +and a ball of radius r and r is the + + + align:start position:0% +and a ball of radius r and r is the +analog of p. + + align:start position:0% + + + + align:start position:0% + +So all the sizes of things we would we + + align:start position:0% +So all the sizes of things we would we + + + align:start position:0% +So all the sizes of things we would we +could think of them as powers of r. + + align:start position:0% +could think of them as powers of r. + + + align:start position:0% +could think of them as powers of r. +Yeah. + + align:start position:0% +Yeah. + + + align:start position:0% +Yeah. +>> Do the proofs use kind of similar + + align:start position:0% +>> Do the proofs use kind of similar + + + align:start position:0% +>> Do the proofs use kind of similar +arguments or they completely + + align:start position:0% +arguments or they completely + + + align:start position:0% +arguments or they completely +>> the question is do these two proofs use + + align:start position:0% +>> the question is do these two proofs use + + + align:start position:0% +>> the question is do these two proofs use +similar arguments or are they completely + + align:start position:0% +similar arguments or are they completely + + + align:start position:0% +similar arguments or are they completely +different? Um there are multiple proofs + + align:start position:0% +different? Um there are multiple proofs + + + align:start position:0% +different? Um there are multiple proofs +of this um but at least one of them is + + align:start position:0% +of this um but at least one of them is + + + align:start position:0% +of this um but at least one of them is +very similar to this with one sort of + + align:start position:0% +very similar to this with one sort of + + + align:start position:0% +very similar to this with one sort of +layer of additional ideas + + align:start position:0% +layer of additional ideas + + + align:start position:0% +layer of additional ideas +and so yeah so my plan is that we'll + + align:start position:0% +and so yeah so my plan is that we'll + + + align:start position:0% +and so yeah so my plan is that we'll +we'll do this and then we'll talk about + + align:start position:0% +we'll do this and then we'll talk about + + + align:start position:0% +we'll do this and then we'll talk about +the additional ideas to do this. + + align:start position:0% + + + + align:start position:0% + +Okay cool. Well so the key difference + + align:start position:0% +Okay cool. Well so the key difference + + + align:start position:0% +Okay cool. Well so the key difference +between FQ and FP is that FQ has a sub + + align:start position:0% +between FQ and FP is that FQ has a sub + + + align:start position:0% +between FQ and FP is that FQ has a sub +field and FP has no sub field. Now, it's + + align:start position:0% +field and FP has no sub field. Now, it's + + + align:start position:0% +field and FP has no sub field. Now, it's +elementary to check that FP has no + + align:start position:0% +elementary to check that FP has no + + + align:start position:0% +elementary to check that FP has no +subfield, but because we're proving some + + align:start position:0% +subfield, but because we're proving some + + + align:start position:0% +subfield, but because we're proving some +kind of quantitative estimates, we need + + align:start position:0% +kind of quantitative estimates, we need + + + align:start position:0% +kind of quantitative estimates, we need +some quantitative lema that that says + + align:start position:0% +some quantitative lema that that says + + + align:start position:0% +some quantitative lema that that says +that FP not only has no subfield, but it + + align:start position:0% +that FP not only has no subfield, but it + + + align:start position:0% +that FP not only has no subfield, but it +doesn't have anything that's kind of + + align:start position:0% +doesn't have anything that's kind of + + + align:start position:0% +doesn't have anything that's kind of +approximately a sub field. Um, so the + + align:start position:0% +approximately a sub field. Um, so the + + + align:start position:0% +approximately a sub field. Um, so the +main goal for today will be to uh to to + + align:start position:0% +main goal for today will be to uh to to + + + align:start position:0% +main goal for today will be to uh to to +prove to develop uh lambas like that. + + align:start position:0% +prove to develop uh lambas like that. + + + align:start position:0% +prove to develop uh lambas like that. +And let me show you. So, so here's the + + align:start position:0% +And let me show you. So, so here's the + + + align:start position:0% +And let me show you. So, so here's the +first version of a lema like that. + + align:start position:0% + + + + align:start position:0% + +level one. Actually, let me do I think + + align:start position:0% +level one. Actually, let me do I think + + + align:start position:0% +level one. Actually, let me do I think +we need a little notation. + + align:start position:0% + + + + align:start position:0% + +Okay, so suppose that A is a subset of + + align:start position:0% +Okay, so suppose that A is a subset of + + + align:start position:0% +Okay, so suppose that A is a subset of +FP. + + align:start position:0% +FP. + + + align:start position:0% +FP. +If I write a + a, then that means the + + align:start position:0% +If I write a + a, then that means the + + + align:start position:0% +If I write a + a, then that means the +set of all the sums a1 plus a2 where a1 + + align:start position:0% +set of all the sums a1 plus a2 where a1 + + + align:start position:0% +set of all the sums a1 plus a2 where a1 +and a2 are a and we could write a * a. + + align:start position:0% +and a2 are a and we could write a * a. + + + align:start position:0% +and a2 are a and we could write a * a. +That's the set of all the products a1 * + + align:start position:0% +That's the set of all the products a1 * + + + align:start position:0% +That's the set of all the products a1 * +a2 a1 and a2 and a + + align:start position:0% +a2 a1 and a2 and a + + + align:start position:0% +a2 a1 and a2 and a +and so on. So there you can write a lot + + align:start position:0% +and so on. So there you can write a lot + + + align:start position:0% +and so on. So there you can write a lot +of similar things like this and um I + + align:start position:0% +of similar things like this and um I + + + align:start position:0% +of similar things like this and um I +think it'll be clear what they all mean + + align:start position:0% +think it'll be clear what they all mean + + + align:start position:0% +think it'll be clear what they all mean +but if it's not of course we we'll talk + + align:start position:0% +but if it's not of course we we'll talk + + + align:start position:0% +but if it's not of course we we'll talk +about it. Okay, so here's the lema. It's + + align:start position:0% +about it. Okay, so here's the lema. It's + + + align:start position:0% +about it. Okay, so here's the lema. It's +a quantitative lema that says that um + + align:start position:0% +a quantitative lema that says that um + + + align:start position:0% +a quantitative lema that says that um +that no subset behaves too much like a + + align:start position:0% +that no subset behaves too much like a + + + align:start position:0% +that no subset behaves too much like a +sub field. + + align:start position:0% +sub field. + + + align:start position:0% +sub field. +So it says if A is a subset of FP + + align:start position:0% +So it says if A is a subset of FP + + + align:start position:0% +So it says if A is a subset of FP +then either + + align:start position:0% + + + + align:start position:0% + +one option is that A minus A over A + + align:start position:0% +one option is that A minus A over A + + + align:start position:0% +one option is that A minus A over A +minus A is all the death P + + align:start position:0% + + + + align:start position:0% + +and the second option + + align:start position:0% +and the second option + + + align:start position:0% +and the second option +is that + + align:start position:0% +is that + + + align:start position:0% +is that +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +if you multiply try and add stuff in a + + align:start position:0% +if you multiply try and add stuff in a + + + align:start position:0% +if you multiply try and add stuff in a +and subtract stuff. A lot of times it + + align:start position:0% +and subtract stuff. A lot of times it + + + align:start position:0% +and subtract stuff. A lot of times it +will get bigger. 1 2 3 4 5 six. Six + + align:start position:0% +will get bigger. 1 2 3 4 5 six. Six + + + align:start position:0% +will get bigger. 1 2 3 4 5 six. Six +might be enough. I think it might be + + align:start position:0% +might be enough. I think it might be + + + align:start position:0% +might be enough. I think it might be +eight. + + align:start position:0% +eight. + + + align:start position:0% +eight. +[Applause] + + align:start position:0% + + + + align:start position:0% + +Okay. So, one possibility is if you + + align:start position:0% +Okay. So, one possibility is if you + + + align:start position:0% +Okay. So, one possibility is if you +multiply, add and subtract elements of A + + align:start position:0% +multiply, add and subtract elements of A + + + align:start position:0% +multiply, add and subtract elements of A +lot of times, then you get a lot more + + align:start position:0% +lot of times, then you get a lot more + + + align:start position:0% +lot of times, then you get a lot more +stuff than just a. So this says A is not + + align:start position:0% +stuff than just a. So this says A is not + + + align:start position:0% +stuff than just a. So this says A is not +too close to a sub field. And the other + + align:start position:0% +too close to a sub field. And the other + + + align:start position:0% +too close to a sub field. And the other +options is if you do this you get all of + + align:start position:0% +options is if you do this you get all of + + + align:start position:0% +options is if you do this you get all of +FP. + + align:start position:0% +FP. + + + align:start position:0% +FP. +Now of course A could have been almost + + align:start position:0% +Now of course A could have been almost + + + align:start position:0% +Now of course A could have been almost +all of FP already. So then it is kind of + + align:start position:0% +all of FP already. So then it is kind of + + + align:start position:0% +all of FP already. So then it is kind of +almost a field. But if A was originally + + align:start position:0% +almost a field. But if A was originally + + + align:start position:0% +almost a field. But if A was originally +a lot smaller than FP then in this case + + align:start position:0% +a lot smaller than FP then in this case + + + align:start position:0% +a lot smaller than FP then in this case +this thing is a lot bigger than A. + + align:start position:0% + + + + align:start position:0% + +Okay. + + align:start position:0% +Okay. + + + align:start position:0% +Okay. +Um, + + align:start position:0% +Um, + + + align:start position:0% +Um, +cool. + + align:start position:0% + + + + align:start position:0% + +All right. + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +So, here is the proof. + + align:start position:0% +So, here is the proof. + + + align:start position:0% +So, here is the proof. +Um, observation one. + + align:start position:0% + + + + align:start position:0% + +So if uh c is not in a minus a over a + + align:start position:0% +So if uh c is not in a minus a over a + + + align:start position:0% +So if uh c is not in a minus a over a +minus a + + align:start position:0% +minus a + + + align:start position:0% +minus a +um then + + align:start position:0% +um then + + + align:start position:0% +um then +a + c a + + align:start position:0% +a + c a + + + align:start position:0% +a + c a +has size a squ. + + align:start position:0% + + + + align:start position:0% + +Okay. Let me make sure it's clear what + + align:start position:0% +Okay. Let me make sure it's clear what + + + align:start position:0% +Okay. Let me make sure it's clear what +all the notation means. So if I write + + align:start position:0% +all the notation means. So if I write + + + align:start position:0% +all the notation means. So if I write +this thing, I have four copies of A. So + + align:start position:0% +this thing, I have four copies of A. So + + + align:start position:0% +this thing, I have four copies of A. So +you take A1, A2, A3, A4, any four guys + + align:start position:0% +you take A1, A2, A3, A4, any four guys + + + align:start position:0% +you take A1, A2, A3, A4, any four guys +in A and sort of plug them in for the + + align:start position:0% +in A and sort of plug them in for the + + + align:start position:0% +in A and sort of plug them in for the +capital A. All the things you can get. + + align:start position:0% +capital A. All the things you can get. + + + align:start position:0% +capital A. All the things you can get. +That's what this set is. And similarly + + align:start position:0% +That's what this set is. And similarly + + + align:start position:0% +That's what this set is. And similarly +over here the lowerase C is a particular + + align:start position:0% +over here the lowerase C is a particular + + + align:start position:0% +over here the lowerase C is a particular +element of FP and this means take any A1 + + align:start position:0% +element of FP and this means take any A1 + + + align:start position:0% +element of FP and this means take any A1 +and A2 and and do this. + + align:start position:0% +and A2 and and do this. + + + align:start position:0% +and A2 and and do this. +Okay. Um so the proof of observation one + + align:start position:0% +Okay. Um so the proof of observation one + + + align:start position:0% +Okay. Um so the proof of observation one +is quite simple. So suppose that I have + + align:start position:0% +is quite simple. So suppose that I have + + + align:start position:0% +is quite simple. So suppose that I have +two different uh ele uh elements in here + + align:start position:0% +two different uh ele uh elements in here + + + align:start position:0% +two different uh ele uh elements in here +but that are equal to each other. So + + align:start position:0% +but that are equal to each other. So + + + align:start position:0% +but that are equal to each other. So +suppose a1 + c a2 is the same as a1 + + align:start position:0% +suppose a1 + c a2 is the same as a1 + + + align:start position:0% +suppose a1 + c a2 is the same as a1 +prime plus c a2 prime. + + align:start position:0% +prime plus c a2 prime. + + + align:start position:0% +prime plus c a2 prime. +Well, if I do a little algebra, I can + + align:start position:0% +Well, if I do a little algebra, I can + + + align:start position:0% +Well, if I do a little algebra, I can +solve this for C. And I discover that C + + align:start position:0% +solve this for C. And I discover that C + + + align:start position:0% +solve this for C. And I discover that C +is um A1 prime minus A1 + + align:start position:0% +is um A1 prime minus A1 + + + align:start position:0% +is um A1 prime minus A1 +/ A2 - A2 prime, which is in A minus A. + + align:start position:0% +/ A2 - A2 prime, which is in A minus A. + + + align:start position:0% +/ A2 - A2 prime, which is in A minus A. +So if C is not in A minus A, sorry, + + align:start position:0% +So if C is not in A minus A, sorry, + + + align:start position:0% +So if C is not in A minus A, sorry, +which is in A minus A over A minus A. + + align:start position:0% +which is in A minus A over A minus A. + + + align:start position:0% +which is in A minus A over A minus A. +So if C is not in here, then all of + + align:start position:0% +So if C is not in here, then all of + + + align:start position:0% +So if C is not in here, then all of +these different representations are + + align:start position:0% +these different representations are + + + align:start position:0% +these different representations are +actually different numbers. So the size + + align:start position:0% +actually different numbers. So the size + + + align:start position:0% +actually different numbers. So the size +of this set is A^ squ. + + align:start position:0% + + + + align:start position:0% + +Okay. Now if you want to be really + + align:start position:0% +Okay. Now if you want to be really + + + align:start position:0% +Okay. Now if you want to be really +careful, maybe we should worry about + + align:start position:0% +careful, maybe we should worry about + + + align:start position:0% +careful, maybe we should worry about +whether I have divided by zero. But if + + align:start position:0% +whether I have divided by zero. But if + + + align:start position:0% +whether I have divided by zero. But if +a2 is equal to a2 prime, then the only + + align:start position:0% +a2 is equal to a2 prime, then the only + + + align:start position:0% +a2 is equal to a2 prime, then the only +way that the top equation could be true + + align:start position:0% +way that the top equation could be true + + + align:start position:0% +way that the top equation could be true +is if also a1 is equal to a1 prime and + + align:start position:0% +is if also a1 is equal to a1 prime and + + + align:start position:0% +is if also a1 is equal to a1 prime and +then I just had the same thing. Okay. + + align:start position:0% +then I just had the same thing. Okay. + + + align:start position:0% +then I just had the same thing. Okay. +All right. Great. + + align:start position:0% +All right. Great. + + + align:start position:0% +All right. Great. +Okay. So, + + align:start position:0% +Okay. So, + + + align:start position:0% +Okay. So, +so if I can locate some C that is in um + + align:start position:0% +so if I can locate some C that is in um + + + align:start position:0% +so if I can locate some C that is in um +you know the ring of stuff I can make by + + align:start position:0% +you know the ring of stuff I can make by + + + align:start position:0% +you know the ring of stuff I can make by +adding and multip maybe the if I can add + + align:start position:0% +adding and multip maybe the if I can add + + + align:start position:0% +adding and multip maybe the if I can add +and subtract and multiply and divide a + + align:start position:0% +and subtract and multiply and divide a + + + align:start position:0% +and subtract and multiply and divide a +bunch of elements of A and I can locate + + align:start position:0% +bunch of elements of A and I can locate + + + align:start position:0% +bunch of elements of A and I can locate +some C which is not in here then I can + + align:start position:0% +some C which is not in here then I can + + + align:start position:0% +some C which is not in here then I can +use this observation and I can get some + + align:start position:0% +use this observation and I can get some + + + align:start position:0% +use this observation and I can get some +I can show that I can build out of A + + align:start position:0% +I can show that I can build out of A + + + align:start position:0% +I can show that I can build out of A +many different things. + + align:start position:0% +many different things. + + + align:start position:0% +many different things. +Okay, cool. + + align:start position:0% +Okay, cool. + + + align:start position:0% +Okay, cool. +Okay, + + align:start position:0% +Okay, + + + align:start position:0% +Okay, +now somewhere in our proof, we have to + + align:start position:0% +now somewhere in our proof, we have to + + + align:start position:0% +now somewhere in our proof, we have to +use that FP is a prime field. + + align:start position:0% +use that FP is a prime field. + + + align:start position:0% +use that FP is a prime field. +It wouldn't work in FQ and we haven't + + align:start position:0% +It wouldn't work in FQ and we haven't + + + align:start position:0% +It wouldn't work in FQ and we haven't +used it yet. Well, how are we going to + + align:start position:0% +used it yet. Well, how are we going to + + + align:start position:0% +used it yet. Well, how are we going to +use it? Well, let's just remember how we + + align:start position:0% +use it? Well, let's just remember how we + + + align:start position:0% +use it? Well, let's just remember how we +would prove that FP is a prime field. + + align:start position:0% +would prove that FP is a prime field. + + + align:start position:0% +would prove that FP is a prime field. +Um, sorry, how would we prove that FP + + align:start position:0% +Um, sorry, how would we prove that FP + + + align:start position:0% +Um, sorry, how would we prove that FP +has no sub fields? How are we going to + + align:start position:0% +has no sub fields? How are we going to + + + align:start position:0% +has no sub fields? How are we going to +prove? Well, um, if it had a sub field, + + align:start position:0% +prove? Well, um, if it had a sub field, + + + align:start position:0% +prove? Well, um, if it had a sub field, +it would have to contain one + + align:start position:0% +it would have to contain one + + + align:start position:0% +it would have to contain one +and then it would have to contain then + + align:start position:0% +and then it would have to contain then + + + align:start position:0% +and then it would have to contain then +it would be closed under addition. So, + + align:start position:0% +it would be closed under addition. So, + + + align:start position:0% +it would be closed under addition. So, +it would have to contain two and three + + align:start position:0% +it would have to contain two and three + + + align:start position:0% +it would have to contain two and three +and four and so on and then it would + + align:start position:0% +and four and so on and then it would + + + align:start position:0% +and four and so on and then it would +have to contain all of FP. + + align:start position:0% +have to contain all of FP. + + + align:start position:0% +have to contain all of FP. +Okay. Um, + + align:start position:0% +Okay. Um, + + + align:start position:0% +Okay. Um, +so we we're basically going to use that + + align:start position:0% +so we we're basically going to use that + + + align:start position:0% +so we we're basically going to use that +argument in observation two. + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% + + + + align:start position:0% + +Okay. So observation two if a minus a + + align:start position:0% +Okay. So observation two if a minus a + + + align:start position:0% +Okay. So observation two if a minus a +over a minus a is not everything + + align:start position:0% +over a minus a is not everything + + + align:start position:0% +over a minus a is not everything +um then there exists some b in a minus a + + align:start position:0% +um then there exists some b in a minus a + + + align:start position:0% +um then there exists some b in a minus a +over a minus a + + align:start position:0% +over a minus a + + + align:start position:0% +over a minus a +so that b + 1 is not in a minus a over a + + align:start position:0% +so that b + 1 is not in a minus a over a + + + align:start position:0% +so that b + 1 is not in a minus a over a +minus + + align:start position:0% + + + + align:start position:0% + +Right. + + align:start position:0% + + + + align:start position:0% + +Right. Okay. So why is it um so so zero + + align:start position:0% +Right. Okay. So why is it um so so zero + + + align:start position:0% +Right. Okay. So why is it um so so zero +is an a minus a over a minus a. It's a + + align:start position:0% +is an a minus a over a minus a. It's a + + + align:start position:0% +is an a minus a over a minus a. It's a +proof of observation too. + + align:start position:0% + + + + align:start position:0% + +zero is in there because you could + + align:start position:0% +zero is in there because you could + + + align:start position:0% +zero is in there because you could +choose these to be the same and you can + + align:start position:0% +choose these to be the same and you can + + + align:start position:0% +choose these to be the same and you can +choose those to be different. + + align:start position:0% +choose those to be different. + + + align:start position:0% +choose those to be different. +Um okay if one is not + + align:start position:0% +Um okay if one is not + + + align:start position:0% +Um okay if one is not +uh yeah okay so then then we just if + + align:start position:0% +uh yeah okay so then then we just if + + + align:start position:0% +uh yeah okay so then then we just if +okay either everybody in FP is in A + + align:start position:0% +okay either everybody in FP is in A + + + align:start position:0% +okay either everybody in FP is in A +minus A minus A minus A or somebody's + + align:start position:0% +minus A minus A minus A or somebody's + + + align:start position:0% +minus A minus A minus A or somebody's +not and so then we take uh B + one is + + align:start position:0% +not and so then we take uh B + one is + + + align:start position:0% +not and so then we take uh B + one is +the smallest + + align:start position:0% +the smallest + + + align:start position:0% +the smallest +number which is not + + align:start position:0% +number which is not + + + align:start position:0% +number which is not +an A minus A over A minus A + + align:start position:0% +an A minus A over A minus A + + + align:start position:0% +an A minus A over A minus A +and there we go. + + align:start position:0% + + + + align:start position:0% + +Okay. And the special thing that we're + + align:start position:0% +Okay. And the special thing that we're + + + align:start position:0% +Okay. And the special thing that we're +using about FP we've used that we have + + align:start position:0% +using about FP we've used that we have + + + align:start position:0% +using about FP we've used that we have +it's a prime field is just we're using + + align:start position:0% +it's a prime field is just we're using + + + align:start position:0% +it's a prime field is just we're using +that if you start at zero and you keep + + align:start position:0% +that if you start at zero and you keep + + + align:start position:0% +that if you start at zero and you keep +adding one you get all the elements. + + align:start position:0% +adding one you get all the elements. + + + align:start position:0% +adding one you get all the elements. +Okay. So that's the proof of observation + + align:start position:0% +Okay. So that's the proof of observation + + + align:start position:0% +Okay. So that's the proof of observation +too. + + align:start position:0% +too. + + + align:start position:0% +too. +Um + + align:start position:0% +Um + + + align:start position:0% +Um +and so now we are basically done. So now + + align:start position:0% +and so now we are basically done. So now + + + align:start position:0% +and so now we are basically done. So now +we have seen that if a minus a over a + + align:start position:0% +we have seen that if a minus a over a + + + align:start position:0% +we have seen that if a minus a over a +minus a is not fp + + align:start position:0% +minus a is not fp + + + align:start position:0% +minus a is not fp +then if you take a and you add this b + + + align:start position:0% +then if you take a and you add this b + + + + align:start position:0% +then if you take a and you add this b + +one. So b is an a minus a over a minus + + align:start position:0% +one. So b is an a minus a over a minus + + + align:start position:0% +one. So b is an a minus a over a minus +a. I'm going to add one to it. So b + + + align:start position:0% +a. I'm going to add one to it. So b + + + + align:start position:0% +a. I'm going to add one to it. So b + +one is in here. There is bigger than a + + align:start position:0% +one is in here. There is bigger than a + + + align:start position:0% +one is in here. There is bigger than a +square. + + align:start position:0% + + + + align:start position:0% + +So if I take six elements of a and I do + + align:start position:0% +So if I take six elements of a and I do + + + align:start position:0% +So if I take six elements of a and I do +this uh the number of different guys I + + align:start position:0% +this uh the number of different guys I + + + align:start position:0% +this uh the number of different guys I +will get is is really much bigger than + + align:start position:0% + + + + align:start position:0% + +okay and then this doesn't look exactly + + align:start position:0% +okay and then this doesn't look exactly + + + align:start position:0% +okay and then this doesn't look exactly +like my two but I just like clear the + + align:start position:0% +like my two but I just like clear the + + + align:start position:0% +like my two but I just like clear the +denominator and expand things out. + + align:start position:0% + + + + align:start position:0% + +So when I clear the denominator, I'll + + align:start position:0% +So when I clear the denominator, I'll + + + align:start position:0% +So when I clear the denominator, I'll +get + + align:start position:0% +get + + + align:start position:0% +get +a * a minus a * a from this guy. Inside + + align:start position:0% +a * a minus a * a from this guy. Inside + + + align:start position:0% +a * a minus a * a from this guy. Inside +of here, I'll have a minus a plus a + + align:start position:0% +of here, I'll have a minus a plus a + + + align:start position:0% +of here, I'll have a minus a plus a +minus a all multiplied by a. Okay, I + + align:start position:0% +minus a all multiplied by a. Okay, I + + + align:start position:0% +minus a all multiplied by a. Okay, I +have a bunch of stuff. + + align:start position:0% + + + + align:start position:0% + +Okay. + + align:start position:0% +Okay. + + + align:start position:0% +Okay. +So, I know so Nets Katz and I are old + + align:start position:0% +So, I know so Nets Katz and I are old + + + align:start position:0% +So, I know so Nets Katz and I are old +collaborators and I remember talking + + align:start position:0% +collaborators and I remember talking + + + align:start position:0% +collaborators and I remember talking +with him about this and and uh that + + align:start position:0% +with him about this and and uh that + + + align:start position:0% +with him about this and and uh that +it it took quite a while for them to + + align:start position:0% +it it took quite a while for them to + + + align:start position:0% +it it took quite a while for them to +figure out how to get started on this + + align:start position:0% +figure out how to get started on this + + + align:start position:0% +figure out how to get started on this +problem. + + align:start position:0% +problem. + + + align:start position:0% +problem. +Um okay, now looking back at this this + + align:start position:0% +Um okay, now looking back at this this + + + align:start position:0% +Um okay, now looking back at this this +this proof is really clean. this lema is + + align:start position:0% +this proof is really clean. this lema is + + + align:start position:0% +this proof is really clean. this lema is +perhaps not the the statement of the + + align:start position:0% +perhaps not the the statement of the + + + align:start position:0% +perhaps not the the statement of the +lema is perhaps not the nicest thing + + align:start position:0% +lema is perhaps not the nicest thing + + + align:start position:0% +lema is perhaps not the nicest thing +that you might like. Um and um + + align:start position:0% +that you might like. Um and um + + + align:start position:0% +that you might like. Um and um +[Applause] + + align:start position:0% + + + + align:start position:0% + +so there are much there are kind of + + align:start position:0% +so there are much there are kind of + + + align:start position:0% +so there are much there are kind of +cleaner things like for example later + + align:start position:0% +cleaner things like for example later + + + align:start position:0% +cleaner things like for example later +today we'll show that you know just just + + align:start position:0% +today we'll show that you know just just + + + align:start position:0% +today we'll show that you know just just +this is significantly bigger than a + + align:start position:0% +this is significantly bigger than a + + + align:start position:0% +this is significantly bigger than a +um and and different variations. + + align:start position:0% +um and and different variations. + + + align:start position:0% +um and and different variations. +Okay. + + align:start position:0% + + + + align:start position:0% + +Um, + + align:start position:0% + + + + align:start position:0% + +so maybe we should mention we could ask + + align:start position:0% +so maybe we should mention we could ask + + + align:start position:0% +so maybe we should mention we could ask +some much simpler questions like we + + align:start position:0% +some much simpler questions like we + + + align:start position:0% +some much simpler questions like we +could just say um if you have a subset + + align:start position:0% +could just say um if you have a subset + + + align:start position:0% +could just say um if you have a subset +of FP called A, is it true that A plus A + + align:start position:0% +of FP called A, is it true that A plus A + + + align:start position:0% +of FP called A, is it true that A plus A +is always much bigger than A? + + align:start position:0% +is always much bigger than A? + + + align:start position:0% +is always much bigger than A? +That's true for most subsets, but it's + + align:start position:0% +That's true for most subsets, but it's + + + align:start position:0% +That's true for most subsets, but it's +not true for all of them. Um, but + + align:start position:0% +not true for all of them. Um, but + + + align:start position:0% +not true for all of them. Um, but +thinking about that much simpler + + align:start position:0% +thinking about that much simpler + + + align:start position:0% +thinking about that much simpler +question is actually uh so that that's + + align:start position:0% +question is actually uh so that that's + + + align:start position:0% +question is actually uh so that that's +like a a foundational question in in + + align:start position:0% +like a a foundational question in in + + + align:start position:0% +like a a foundational question in in +additive combinatorics to understand + + align:start position:0% +additive combinatorics to understand + + + align:start position:0% +additive combinatorics to understand +that um and and understanding that well + + align:start position:0% +that um and and understanding that well + + + align:start position:0% +that um and and understanding that well +feeds into being able to understand this + + align:start position:0% +feeds into being able to understand this + + + align:start position:0% +feeds into being able to understand this +this stuff better. Okay. So, let me pose + + align:start position:0% +this stuff better. Okay. So, let me pose + + + align:start position:0% +this stuff better. Okay. So, let me pose +this on the board and we'll start to + + align:start position:0% +this on the board and we'll start to + + + align:start position:0% +this on the board and we'll start to +talk about it. + + align:start position:0% + + + + align:start position:0% + +So my question for us is + + align:start position:0% +So my question for us is + + + align:start position:0% +So my question for us is +um when + + align:start position:0% +um when + + + align:start position:0% +um when +is a + a + + align:start position:0% +is a + a + + + align:start position:0% +is a + a +small? + + align:start position:0% + + + + align:start position:0% + +So here I have in mind that A is a + + align:start position:0% +So here I have in mind that A is a + + + align:start position:0% +So here I have in mind that A is a +subset of FP. Although we could have a + + align:start position:0% +subset of FP. Although we could have a + + + align:start position:0% +subset of FP. Although we could have a +very similar conversation if A was a + + align:start position:0% +very similar conversation if A was a + + + align:start position:0% +very similar conversation if A was a +subset of Z or A was a subset of R or + + align:start position:0% +subset of Z or A was a subset of R or + + + align:start position:0% +subset of Z or A was a subset of R or +dot dot dot. + + align:start position:0% + + + + align:start position:0% + +Okay. Can anybody think of a subset if + + align:start position:0% +Okay. Can anybody think of a subset if + + + align:start position:0% +Okay. Can anybody think of a subset if +FP or A plus A is only a tiny bit bigger + + align:start position:0% +FP or A plus A is only a tiny bit bigger + + + align:start position:0% +FP or A plus A is only a tiny bit bigger +than A? + + align:start position:0% + + + + align:start position:0% + +Yeah, + + align:start position:0% +Yeah, + + + align:start position:0% +Yeah, +>> is some set + + align:start position:0% +>> is some set + + + align:start position:0% +>> is some set +um + + align:start position:0% +um + + + align:start position:0% +um +and that includes like numbers and then + + align:start position:0% +and that includes like numbers and then + + + align:start position:0% +and that includes like numbers and then +the negative values of those numbers in + + align:start position:0% +the negative values of those numbers in + + + align:start position:0% +the negative values of those numbers in +F like only one 2 -2 or something like + + align:start position:0% +F like only one 2 -2 or something like + + + align:start position:0% +F like only one 2 -2 or something like +that. + + align:start position:0% +that. + + + align:start position:0% +that. +>> Yeah. Yeah. So the comment is maybe I + + align:start position:0% +>> Yeah. Yeah. So the comment is maybe I + + + align:start position:0% +>> Yeah. Yeah. So the comment is maybe I +should have some numbers and negative of + + align:start position:0% +should have some numbers and negative of + + + align:start position:0% +should have some numbers and negative of +those numbers. Let me ask you a more + + align:start position:0% +those numbers. Let me ask you a more + + + align:start position:0% +those numbers. Let me ask you a more +precise question. So you have to choose + + align:start position:0% +precise question. So you have to choose + + + align:start position:0% +precise question. So you have to choose +L numbers in FP and you want to choose + + align:start position:0% +L numbers in FP and you want to choose + + + align:start position:0% +L numbers in FP and you want to choose +them to make A plus A as small as + + align:start position:0% +them to make A plus A as small as + + + align:start position:0% +them to make A plus A as small as +possible. Who would you choose? + + align:start position:0% + + + + align:start position:0% + +>> Yeah. + + align:start position:0% +>> Yeah. + + + align:start position:0% +>> Yeah. +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +>> Yeah, you could choose an arithmetic + + align:start position:0% +>> Yeah, you could choose an arithmetic + + + align:start position:0% +>> Yeah, you could choose an arithmetic +progression. + + align:start position:0% +progression. + + + align:start position:0% +progression. +So example one. + + align:start position:0% +So example one. + + + align:start position:0% +So example one. +Um suppose A was just the numbers from + + align:start position:0% +Um suppose A was just the numbers from + + + align:start position:0% +Um suppose A was just the numbers from +one up to L. + + align:start position:0% +one up to L. + + + align:start position:0% +one up to L. +So a plus a will be the numbers from 2 + + align:start position:0% +So a plus a will be the numbers from 2 + + + align:start position:0% +So a plus a will be the numbers from 2 +to 2 l. Uh so a + a is at most 2 * a. + + align:start position:0% +to 2 l. Uh so a + a is at most 2 * a. + + + align:start position:0% +to 2 l. Uh so a + a is at most 2 * a. +It's tiniest bit less than that but not + + align:start position:0% +It's tiniest bit less than that but not + + + align:start position:0% +It's tiniest bit less than that but not +very important for our discussion. And + + align:start position:0% +very important for our discussion. And + + + align:start position:0% +very important for our discussion. And +this is the small this is the the + + align:start position:0% +this is the small this is the the + + + align:start position:0% +this is the small this is the the +smallest that a plus a could possibly + + align:start position:0% +smallest that a plus a could possibly + + + align:start position:0% +smallest that a plus a could possibly +be. + + align:start position:0% +be. + + + align:start position:0% +be. +Okay. And it doesn't have to be one up + + align:start position:0% +Okay. And it doesn't have to be one up + + + align:start position:0% +Okay. And it doesn't have to be one up +to l. It would work just as well if it + + align:start position:0% +to l. It would work just as well if it + + + align:start position:0% +to l. It would work just as well if it +was an arithmetic progression. So + + align:start position:0% +was an arithmetic progression. So + + + align:start position:0% +was an arithmetic progression. So +example one prime + + align:start position:0% +example one prime + + + align:start position:0% +example one prime +our set A is little a + n d where n goes + + align:start position:0% +our set A is little a + n d where n goes + + + align:start position:0% +our set A is little a + n d where n goes +from one up to l. + + align:start position:0% + + + + align:start position:0% + +Um and then if you think about it a + + align:start position:0% +Um and then if you think about it a + + + align:start position:0% +Um and then if you think about it a +little bit the size of the subset + + align:start position:0% +little bit the size of the subset + + + align:start position:0% +little bit the size of the subset +behaves just the same. + + align:start position:0% + + + + align:start position:0% + +Okay. + + align:start position:0% +Okay. + + + align:start position:0% +Okay. +Um + + align:start position:0% +Um + + + align:start position:0% +Um +there's another example that's a little + + align:start position:0% +there's another example that's a little + + + align:start position:0% +there's another example that's a little +bit more general than this. So this is + + align:start position:0% +bit more general than this. So this is + + + align:start position:0% +bit more general than this. So this is +an arithmetic progression where you have + + align:start position:0% +an arithmetic progression where you have + + + align:start position:0% +an arithmetic progression where you have +just one kind of difference. + + align:start position:0% +just one kind of difference. + + + align:start position:0% +just one kind of difference. +Um + + align:start position:0% +Um + + + align:start position:0% +Um +and you could have something uh + + align:start position:0% +and you could have something uh + + + align:start position:0% +and you could have something uh +uh so you should you could visualize it + + align:start position:0% +uh so you should you could visualize it + + + align:start position:0% +uh so you should you could visualize it +like this. + + align:start position:0% +like this. + + + align:start position:0% +like this. +And you could have a similar thing + + align:start position:0% +And you could have a similar thing + + + align:start position:0% +And you could have a similar thing +involving a two-dimensional grid or a + + align:start position:0% +involving a two-dimensional grid or a + + + align:start position:0% +involving a two-dimensional grid or a +higher dimensional grid. + + align:start position:0% +higher dimensional grid. + + + align:start position:0% +higher dimensional grid. +All right. So example two is that a is a + + align:start position:0% +All right. So example two is that a is a + + + align:start position:0% +All right. So example two is that a is a ++ n1 d1 plus dot dot dot plus n r + + align:start position:0% + + + + align:start position:0% + +where um n i goes from one up to l i. + + align:start position:0% + + + + align:start position:0% + +So what happens when you take a plus a? + + align:start position:0% +So what happens when you take a plus a? + + + align:start position:0% +So what happens when you take a plus a? +It is contained in two little a plus n1 + + align:start position:0% +It is contained in two little a plus n1 + + + align:start position:0% +It is contained in two little a plus n1 +d1 plus dot dot dot plus nr + + align:start position:0% +d1 plus dot dot dot plus nr + + + align:start position:0% +d1 plus dot dot dot plus nr +where now the n i go in between two and + + align:start position:0% +where now the n i go in between two and + + + align:start position:0% +where now the n i go in between two and +2 li. + + align:start position:0% + + + + align:start position:0% + +And so we see from this and I well which + + align:start position:0% +And so we see from this and I well which + + + align:start position:0% +And so we see from this and I well which +so it which is contained in I could put + + align:start position:0% +so it which is contained in I could put + + + align:start position:0% +so it which is contained in I could put +a one um so it's contained in something + + align:start position:0% +a one um so it's contained in something + + + align:start position:0% +a one um so it's contained in something +that is 2 to the r * bigger. So we get a + + align:start position:0% +that is 2 to the r * bigger. So we get a + + + align:start position:0% +that is 2 to the r * bigger. So we get a ++ a is bounded by 2 to the r * a. + + align:start position:0% + + + + align:start position:0% + +So this thing here is called a + + align:start position:0% +So this thing here is called a + + + align:start position:0% +So this thing here is called a +generalized arithmetic progression. It + + align:start position:0% +generalized arithmetic progression. It + + + align:start position:0% +generalized arithmetic progression. It +has a dimension little r and it has a + + align:start position:0% +has a dimension little r and it has a + + + align:start position:0% +has a dimension little r and it has a +volume or cardality which is + + align:start position:0% +volume or cardality which is + + + align:start position:0% +volume or cardality which is +L1 to LR. + + align:start position:0% + + + + align:start position:0% + +Okay. Um + + align:start position:0% +Okay. Um + + + align:start position:0% +Okay. Um +can anybody think of any others? + + align:start position:0% + + + + align:start position:0% + +So it is hard to think of other ones and + + align:start position:0% +So it is hard to think of other ones and + + + align:start position:0% +So it is hard to think of other ones and +in some sense and and depending on how + + align:start position:0% +in some sense and and depending on how + + + align:start position:0% +in some sense and and depending on how +we quantify it a little bit um these + + align:start position:0% +we quantify it a little bit um these + + + align:start position:0% +we quantify it a little bit um these +sets or maybe these sets and their close + + align:start position:0% +sets or maybe these sets and their close + + + align:start position:0% +sets or maybe these sets and their close +cousins appear to be the only sets that + + align:start position:0% +cousins appear to be the only sets that + + + align:start position:0% +cousins appear to be the only sets that +have a really small subset + + align:start position:0% +have a really small subset + + + align:start position:0% +have a really small subset +and um this was investigated by framan + + align:start position:0% +and um this was investigated by framan + + + align:start position:0% +and um this was investigated by framan +starting in the 60s and 70s and he + + align:start position:0% +starting in the 60s and 70s and he + + + align:start position:0% +starting in the 60s and 70s and he +proved a theorem to that effect called + + align:start position:0% +proved a theorem to that effect called + + + align:start position:0% +proved a theorem to that effect called +framan's theorem Um + + align:start position:0% +framan's theorem Um + + + align:start position:0% +framan's theorem Um +and um + + align:start position:0% +and um + + + align:start position:0% +and um +uh and this was this is a a cornerstone + + align:start position:0% +uh and this was this is a a cornerstone + + + align:start position:0% +uh and this was this is a a cornerstone +of additive combinatorics. + + align:start position:0% + + + + align:start position:0% + +Um Framan's + + align:start position:0% +Um Framan's + + + align:start position:0% +Um Framan's +Framan's proof was was somewhat + + align:start position:0% +Framan's proof was was somewhat + + + align:start position:0% +Framan's proof was was somewhat +difficult to read and Rusa thought a lot + + align:start position:0% +difficult to read and Rusa thought a lot + + + align:start position:0% +difficult to read and Rusa thought a lot +about it and clarified it and so this is + + align:start position:0% +about it and clarified it and so this is + + + align:start position:0% +about it and clarified it and so this is +now called uh the Framan Rousa theory. + + align:start position:0% + + + + align:start position:0% + +Okay. So it says the following thing. + + align:start position:0% +Okay. So it says the following thing. + + + align:start position:0% +Okay. So it says the following thing. +Says that if a + + align:start position:0% +Says that if a + + + align:start position:0% +Says that if a +um + + align:start position:0% + + + + align:start position:0% + +so if a is in z the same thing would be + + align:start position:0% +so if a is in z the same thing would be + + + align:start position:0% +so if a is in z the same thing would be +true in z mod p and a + a is less than + + align:start position:0% +true in z mod p and a + a is less than + + + align:start position:0% +true in z mod p and a + a is less than +or equal to k a. + + align:start position:0% +or equal to k a. + + + align:start position:0% +or equal to k a. +Um then + + align:start position:0% +Um then + + + align:start position:0% +Um then +a is contained in a gap + + align:start position:0% +a is contained in a gap + + + align:start position:0% +a is contained in a gap +with dimension + + align:start position:0% +with dimension + + + align:start position:0% +with dimension +uh little r that only depends on k and + + align:start position:0% +uh little r that only depends on k and + + + align:start position:0% +uh little r that only depends on k and +volume at most uh v that only depends on + + align:start position:0% +volume at most uh v that only depends on + + + align:start position:0% +volume at most uh v that only depends on +k times the size of a. + + align:start position:0% + + + + align:start position:0% + +So it roughly says that if a plus a is + + align:start position:0% +So it roughly says that if a plus a is + + + align:start position:0% +So it roughly says that if a plus a is +small it is because a resembles example + + align:start position:0% +small it is because a resembles example + + + align:start position:0% +small it is because a resembles example +two which is a generalization of example + + align:start position:0% +two which is a generalization of example + + + align:start position:0% +two which is a generalization of example +one. + + align:start position:0% +one. + + + align:start position:0% +one. +So in some sense these are the only sets + + align:start position:0% +So in some sense these are the only sets + + + align:start position:0% +So in some sense these are the only sets +that have a really small subset. + + align:start position:0% +that have a really small subset. + + + align:start position:0% +that have a really small subset. +Okay. So this is an important theorem in + + align:start position:0% +Okay. So this is an important theorem in + + + align:start position:0% +Okay. So this is an important theorem in +additive combinotaurics but there are + + align:start position:0% +additive combinotaurics but there are + + + align:start position:0% +additive combinotaurics but there are +two caveats about it. So one caveat is + + align:start position:0% +two caveats about it. So one caveat is + + + align:start position:0% +two caveats about it. So one caveat is +that it's a it's a pretty deep theorem. + + align:start position:0% +that it's a it's a pretty deep theorem. + + + align:start position:0% +that it's a it's a pretty deep theorem. +The proof is substantial + + align:start position:0% +The proof is substantial + + + align:start position:0% +The proof is substantial +and the other caveat is that the + + align:start position:0% +and the other caveat is that the + + + align:start position:0% +and the other caveat is that the +quantitative bounds are weak. + + align:start position:0% + + + + align:start position:0% + +Um so in the original version + + align:start position:0% + + + + align:start position:0% + +r of k was quite large. So r of k was + + align:start position:0% +r of k was quite large. So r of k was + + + align:start position:0% +r of k was quite large. So r of k was +something like x of k to a power and v + + align:start position:0% +something like x of k to a power and v + + + align:start position:0% +something like x of k to a power and v +of k was even larger. It's like x of x + + align:start position:0% +of k was even larger. It's like x of x + + + align:start position:0% +of k was even larger. It's like x of x +of k to a power. + + align:start position:0% + + + + align:start position:0% + +Okay. Um now + + align:start position:0% +Okay. Um now + + + align:start position:0% +Okay. Um now +it is a trivial fact that any set A is + + align:start position:0% +it is a trivial fact that any set A is + + + align:start position:0% +it is a trivial fact that any set A is +contained in a generalized arithmetic + + align:start position:0% +contained in a generalized arithmetic + + + align:start position:0% +contained in a generalized arithmetic +progression of dimension equal to the + + align:start position:0% +progression of dimension equal to the + + + align:start position:0% +progression of dimension equal to the +size of A. + + align:start position:0% +size of A. + + + align:start position:0% +size of A. +So this is only interesting if R of K is + + align:start position:0% +So this is only interesting if R of K is + + + align:start position:0% +So this is only interesting if R of K is +smaller than the size of A. + + align:start position:0% +smaller than the size of A. + + + align:start position:0% +smaller than the size of A. +Um so this was only interesting + + align:start position:0% +Um so this was only interesting + + + align:start position:0% +Um so this was only interesting +only meaningful let's say + + align:start position:0% + + + + align:start position:0% + +if k was quite small. + + align:start position:0% + + + + align:start position:0% + +Uh there's a big in um goal in additive + + align:start position:0% +Uh there's a big in um goal in additive + + + align:start position:0% +Uh there's a big in um goal in additive +combinatorics to improve the + + align:start position:0% +combinatorics to improve the + + + align:start position:0% +combinatorics to improve the +quantitative bounds in framan's theorem + + align:start position:0% +quantitative bounds in framan's theorem + + + align:start position:0% +quantitative bounds in framan's theorem +and um + + align:start position:0% +and um + + + align:start position:0% +and um +one benchmark is a conjecture called the + + align:start position:0% +one benchmark is a conjecture called the + + + align:start position:0% +one benchmark is a conjecture called the +polomial frame and roua conjecture which + + align:start position:0% +polomial frame and roua conjecture which + + + align:start position:0% +polomial frame and roua conjecture which +would say something meaningful even if k + + align:start position:0% +would say something meaningful even if k + + + align:start position:0% +would say something meaningful even if k +was a small power of a. So there's a + + align:start position:0% +was a small power of a. So there's a + + + align:start position:0% +was a small power of a. So there's a +conjecture that they would have a + + align:start position:0% +conjecture that they would have a + + + align:start position:0% +conjecture that they would have a +meaningful bound + + align:start position:0% + + + + align:start position:0% + +if k is a to the delta + + align:start position:0% +if k is a to the delta + + + align:start position:0% +if k is a to the delta +for some small but universal + + align:start position:0% + + + + align:start position:0% + +delta bigger than zero. + + align:start position:0% +delta bigger than zero. + + + align:start position:0% +delta bigger than zero. +Okay. And this is still an open + + align:start position:0% +Okay. And this is still an open + + + align:start position:0% +Okay. And this is still an open +conjecture. So it's out of range maybe + + align:start position:0% +conjecture. So it's out of range maybe + + + align:start position:0% +conjecture. So it's out of range maybe +only a little out of range of of uh + + align:start position:0% +only a little out of range of of uh + + + align:start position:0% +only a little out of range of of uh +current techniques. Um but if k was say + + align:start position:0% +current techniques. Um but if k was say + + + align:start position:0% +current techniques. Um but if k was say +I don't know a to the 0.1 + + align:start position:0% +I don't know a to the 0.1 + + + align:start position:0% +I don't know a to the 0.1 +all this stuff about about framan's + + align:start position:0% +all this stuff about about framan's + + + align:start position:0% +all this stuff about about framan's +theorem uh we we are very far from being + + align:start position:0% +theorem uh we we are very far from being + + + align:start position:0% +theorem uh we we are very far from being +able to to deal with that. + + align:start position:0% +able to to deal with that. + + + align:start position:0% +able to to deal with that. +Um + + align:start position:0% +Um + + + align:start position:0% +Um +now if you look at framan's theorem what + + align:start position:0% +now if you look at framan's theorem what + + + align:start position:0% +now if you look at framan's theorem what +we're trying to do is to give a complete + + align:start position:0% +we're trying to do is to give a complete + + + align:start position:0% +we're trying to do is to give a complete +classification of all the sets A that do + + align:start position:0% +classification of all the sets A that do + + + align:start position:0% +classification of all the sets A that do +this + + align:start position:0% +this + + + align:start position:0% +this +and the complete classification is + + align:start position:0% +and the complete classification is + + + align:start position:0% +and the complete classification is +something we only understand if K is + + align:start position:0% +something we only understand if K is + + + align:start position:0% +something we only understand if K is +really really small. + + align:start position:0% +really really small. + + + align:start position:0% +really really small. +But you could also ask for something + + align:start position:0% +But you could also ask for something + + + align:start position:0% +But you could also ask for something +which is not as strong as a complete + + align:start position:0% +which is not as strong as a complete + + + align:start position:0% +which is not as strong as a complete +classification but just some kind of + + align:start position:0% +classification but just some kind of + + + align:start position:0% +classification but just some kind of +interesting information about sets A + + align:start position:0% +interesting information about sets A + + + align:start position:0% +interesting information about sets A +with small subset. + + align:start position:0% +with small subset. + + + align:start position:0% +with small subset. +Um okay + + align:start position:0% +Um okay + + + align:start position:0% +Um okay +so if you look at this example you'll + + align:start position:0% +so if you look at this example you'll + + + align:start position:0% +so if you look at this example you'll +notice that not only it has small subset + + align:start position:0% +notice that not only it has small subset + + + align:start position:0% +notice that not only it has small subset +but it has uh also small a bunch of + + align:start position:0% +but it has uh also small a bunch of + + + align:start position:0% +but it has uh also small a bunch of +other stuff like in these examples a + + align:start position:0% +other stuff like in these examples a + + + align:start position:0% +other stuff like in these examples a +plus a is small also a minus a is small + + align:start position:0% +plus a is small also a minus a is small + + + align:start position:0% +plus a is small also a minus a is small +also a plus a plus a is small + + align:start position:0% +also a plus a plus a is small + + + align:start position:0% +also a plus a plus a is small +um and and and those so those for those + + align:start position:0% +um and and and those so those for those + + + align:start position:0% +um and and and those so those for those +things we have much simpler proofs and + + align:start position:0% +things we have much simpler proofs and + + + align:start position:0% +things we have much simpler proofs and +the quantitative bound s are much better + + align:start position:0% +the quantitative bound s are much better + + + align:start position:0% +the quantitative bound s are much better +and they come from some lemmas that I + + align:start position:0% +and they come from some lemmas that I + + + align:start position:0% +and they come from some lemmas that I +think originally were designed as uh + + align:start position:0% +think originally were designed as uh + + + align:start position:0% +think originally were designed as uh +lemmas for this theorem but which have + + align:start position:0% +lemmas for this theorem but which have + + + align:start position:0% +lemmas for this theorem but which have +lots of independent applications. + + align:start position:0% + + + + align:start position:0% + +Okay. + + align:start position:0% + + + + align:start position:0% + +So this theorem we I don't plan to prove + + align:start position:0% +So this theorem we I don't plan to prove + + + align:start position:0% +So this theorem we I don't plan to prove +in the class but I wanted to mention it + + align:start position:0% +in the class but I wanted to mention it + + + align:start position:0% +in the class but I wanted to mention it +for historical context and and these + + align:start position:0% +for historical context and and these + + + align:start position:0% +for historical context and and these +lemmas are are really important and have + + align:start position:0% +lemmas are are really important and have + + + align:start position:0% +lemmas are are really important and have +reasonable short proofs and I think are + + align:start position:0% +reasonable short proofs and I think are + + + align:start position:0% +reasonable short proofs and I think are +worth for a wide range of people uh + + align:start position:0% +worth for a wide range of people uh + + + align:start position:0% +worth for a wide range of people uh +knowing about. + + align:start position:0% +knowing about. + + + align:start position:0% +knowing about. +[Applause] + + align:start position:0% + + + + align:start position:0% + +Okay, + + align:start position:0% + + + + align:start position:0% + +so the first of the lemas is called the + + align:start position:0% +so the first of the lemas is called the + + + align:start position:0% +so the first of the lemas is called the +rusa triangle inequality. + + align:start position:0% + + + + align:start position:0% + +Okay, so it says if Z is an Aelian group + + align:start position:0% + + + + align:start position:0% + +and A and B and C are subsets of Z, + + align:start position:0% +and A and B and C are subsets of Z, + + + align:start position:0% +and A and B and C are subsets of Z, +then + + align:start position:0% +then + + + align:start position:0% +then +size of A times the size of B minus C is + + align:start position:0% +size of A times the size of B minus C is + + + align:start position:0% +size of A times the size of B minus C is +bounded by the size of A minus B times + + align:start position:0% +bounded by the size of A minus B times + + + align:start position:0% +bounded by the size of A minus B times +the size of A minus C. + + align:start position:0% + + + + align:start position:0% + +Okay, so this might uh take a little + + align:start position:0% +Okay, so this might uh take a little + + + align:start position:0% +Okay, so this might uh take a little +digesting. Have all of these letters + + align:start position:0% +digesting. Have all of these letters + + + align:start position:0% +digesting. Have all of these letters +feels a little bit like alphabet soup. + + align:start position:0% +feels a little bit like alphabet soup. + + + align:start position:0% +feels a little bit like alphabet soup. +Um the fact that we have can put three + + align:start position:0% +Um the fact that we have can put three + + + align:start position:0% +Um the fact that we have can put three +different sets + + align:start position:0% +different sets + + + align:start position:0% +different sets +makes it a little harder to digest but + + align:start position:0% +makes it a little harder to digest but + + + align:start position:0% +makes it a little harder to digest but +it you know of course it makes it more + + align:start position:0% +it you know of course it makes it more + + + align:start position:0% +it you know of course it makes it more +flexible in general and by plugging in + + align:start position:0% +flexible in general and by plugging in + + + align:start position:0% +flexible in general and by plugging in +different choices for these three sets + + align:start position:0% +different choices for these three sets + + + align:start position:0% +different choices for these three sets +you can prove some simpler things. Let + + align:start position:0% +you can prove some simpler things. Let + + + align:start position:0% +you can prove some simpler things. Let +me illustrate this with an example. + + align:start position:0% + + + + align:start position:0% + +As a correlator of this we will see + + align:start position:0% +As a correlator of this we will see + + + align:start position:0% +As a correlator of this we will see +that if the if the sum set is small then + + align:start position:0% +that if the if the sum set is small then + + + align:start position:0% +that if the if the sum set is small then +the difference set is also small. + + align:start position:0% + + + + align:start position:0% + +Okay. + + align:start position:0% +Okay. + + + align:start position:0% +Okay. +So correlary + + align:start position:0% + + + + align:start position:0% + +if a + a is smaller than k * a + + align:start position:0% +if a + a is smaller than k * a + + + align:start position:0% +if a + a is smaller than k * a +then + + align:start position:0% +then + + + align:start position:0% +then +a minus a is smaller than k^ 2 + + align:start position:0% +a minus a is smaller than k^ 2 + + + align:start position:0% +a minus a is smaller than k^ 2 +k^ 2 * a. + + align:start position:0% +k^ 2 * a. + + + align:start position:0% +k^ 2 * a. +So this lema is meaningful as long as k + + align:start position:0% +So this lema is meaningful as long as k + + + align:start position:0% +So this lema is meaningful as long as k +is slightly smaller than the square root + + align:start position:0% +is slightly smaller than the square root + + + align:start position:0% +is slightly smaller than the square root +of a. + + align:start position:0% +of a. + + + align:start position:0% +of a. +So in a in a much wider range than than + + align:start position:0% +So in a in a much wider range than than + + + align:start position:0% +So in a in a much wider range than than +the um uh frame and rusa theorem this is + + align:start position:0% +the um uh frame and rusa theorem this is + + + align:start position:0% +the um uh frame and rusa theorem this is +a meaningful statement. + + align:start position:0% +a meaningful statement. + + + align:start position:0% +a meaningful statement. +Okay. So proof um we're just going to + + align:start position:0% +Okay. So proof um we're just going to + + + align:start position:0% +Okay. So proof um we're just going to +use roua and I have to tell you who are + + align:start position:0% +use roua and I have to tell you who are + + + align:start position:0% +use roua and I have to tell you who are +a and b and c. So A will be A and then I + + align:start position:0% +a and b and c. So A will be A and then I + + + align:start position:0% +a and b and c. So A will be A and then I +think + + align:start position:0% +think + + + align:start position:0% +think +B + + align:start position:0% + + + + align:start position:0% + +uh + + align:start position:0% + + + + align:start position:0% + +yeah B and C are both negative A. + + align:start position:0% +yeah B and C are both negative A. + + + align:start position:0% +yeah B and C are both negative A. +Okay. So if you look at B minus C that's + + align:start position:0% +Okay. So if you look at B minus C that's + + + align:start position:0% +Okay. So if you look at B minus C that's +there's a lot of minus signs. This is a + + align:start position:0% +there's a lot of minus signs. This is a + + + align:start position:0% +there's a lot of minus signs. This is a +little bit silly looking. + + align:start position:0% + + + + align:start position:0% + +Um, + + align:start position:0% +Um, + + + align:start position:0% +Um, +so that's just a minus a. + + align:start position:0% +so that's just a minus a. + + + align:start position:0% +so that's just a minus a. +Okay. And a minus b or a minus c. + + align:start position:0% +Okay. And a minus b or a minus c. + + + align:start position:0% +Okay. And a minus b or a minus c. +They're the same as each other because b + + align:start position:0% +They're the same as each other because b + + + align:start position:0% +They're the same as each other because b +is the same as c. That's a minus a. So + + align:start position:0% +is the same as c. That's a minus a. So + + + align:start position:0% +is the same as c. That's a minus a. So +that's a plus. + + align:start position:0% + + + + align:start position:0% + +Okay. So now if we just plug in ra it + + align:start position:0% +Okay. So now if we just plug in ra it + + + align:start position:0% +Okay. So now if we just plug in ra it +says a * this guy a minus a is less than + + align:start position:0% +says a * this guy a minus a is less than + + + align:start position:0% +says a * this guy a minus a is less than +this guy times this guy that's a + a 2. + + align:start position:0% +this guy times this guy that's a + a 2. + + + align:start position:0% +this guy times this guy that's a + a 2. +And by hypothesis that's smaller than k + + align:start position:0% +And by hypothesis that's smaller than k + + + align:start position:0% +And by hypothesis that's smaller than k +2 a 2. + + align:start position:0% +2 a 2. + + + align:start position:0% +2 a 2. +And if you cancel the factor of a that's + + align:start position:0% +And if you cancel the factor of a that's + + + align:start position:0% +And if you cancel the factor of a that's +it. + + align:start position:0% + + + + align:start position:0% + +Okay. And this has a a very simple proof + + align:start position:0% +Okay. And this has a a very simple proof + + + align:start position:0% +Okay. And this has a a very simple proof +that will fit on this board and which is + + align:start position:0% +that will fit on this board and which is + + + align:start position:0% +that will fit on this board and which is +already says something interesting and + + align:start position:0% +already says something interesting and + + + align:start position:0% +already says something interesting and +non-trivial about how sums and + + align:start position:0% +non-trivial about how sums and + + + align:start position:0% +non-trivial about how sums and +differences and stuff fit together. So + + align:start position:0% +differences and stuff fit together. So + + + align:start position:0% +differences and stuff fit together. So +here's the proof. uh we will construct + + align:start position:0% +here's the proof. uh we will construct + + + align:start position:0% +here's the proof. uh we will construct +a map fee that goes from a cross b minus + + align:start position:0% +a map fee that goes from a cross b minus + + + align:start position:0% +a map fee that goes from a cross b minus +c + + align:start position:0% +c + + + align:start position:0% +c +into a minus b cross a minus c which is + + align:start position:0% +into a minus b cross a minus c which is + + + align:start position:0% +into a minus b cross a minus c which is +injective. + + align:start position:0% + + + + align:start position:0% + +So this is the cardality of this set and + + align:start position:0% +So this is the cardality of this set and + + + align:start position:0% +So this is the cardality of this set and +this is the cardality of that set. And + + align:start position:0% +this is the cardality of that set. And + + + align:start position:0% +this is the cardality of that set. And +the reason that that this set is bigger + + align:start position:0% +the reason that that this set is bigger + + + align:start position:0% +the reason that that this set is bigger +than that set is that we have an + + align:start position:0% +than that set is that we have an + + + align:start position:0% +than that set is that we have an +injection from one into the other. + + align:start position:0% +injection from one into the other. + + + align:start position:0% +injection from one into the other. +How does the injection work? + + align:start position:0% +How does the injection work? + + + align:start position:0% +How does the injection work? +For every D in B minus C, we can choose. + + align:start position:0% +For every D in B minus C, we can choose. + + + align:start position:0% +For every D in B minus C, we can choose. +So by definition, this D can be written + + align:start position:0% +So by definition, this D can be written + + + align:start position:0% +So by definition, this D can be written +as somebody in B minus somebody in C. + + align:start position:0% +as somebody in B minus somebody in C. + + + align:start position:0% +as somebody in B minus somebody in C. +Let's pick them. We choose B of D and B. + + align:start position:0% +Let's pick them. We choose B of D and B. + + + align:start position:0% +Let's pick them. We choose B of D and B. +C of D C so that D is B of D minus C of + + align:start position:0% +C of D C so that D is B of D minus C of + + + align:start position:0% +C of D C so that D is B of D minus C of +D. + + align:start position:0% +D. + + + align:start position:0% +D. +Okay. Now what's our map? + + align:start position:0% +Okay. Now what's our map? + + + align:start position:0% +Okay. Now what's our map? +V takes an A and a D. A lives here and D + + align:start position:0% +V takes an A and a D. A lives here and D + + + align:start position:0% +V takes an A and a D. A lives here and D +lives there. We need to output somebody + + align:start position:0% +lives there. We need to output somebody + + + align:start position:0% +lives there. We need to output somebody +in A minus B. So we take A minus B of D + + align:start position:0% +in A minus B. So we take A minus B of D + + + align:start position:0% +in A minus B. So we take A minus B of D +and then A minus C of D. + + align:start position:0% +and then A minus C of D. + + + align:start position:0% +and then A minus C of D. +So that is a map from here to here. + + align:start position:0% +So that is a map from here to here. + + + align:start position:0% +So that is a map from here to here. +Why is it injective? + + align:start position:0% +Why is it injective? + + + align:start position:0% +Why is it injective? +So to to check that it's injective. + + align:start position:0% + + + + align:start position:0% + +So we're going to suppose + + align:start position:0% +So we're going to suppose + + + align:start position:0% +So we're going to suppose +that v of a d is given to us. It's xy. + + align:start position:0% +that v of a d is given to us. It's xy. + + + align:start position:0% +that v of a d is given to us. It's xy. +And then we're going to find + + align:start position:0% +And then we're going to find + + + align:start position:0% +And then we're going to find +A and D from X and Y + + align:start position:0% +A and D from X and Y + + + align:start position:0% +A and D from X and Y +and from this choice. + + align:start position:0% + + + + align:start position:0% + +So the choice we made once and for all, + + align:start position:0% +So the choice we made once and for all, + + + align:start position:0% +So the choice we made once and for all, +we used it to build the map. And now we + + align:start position:0% +we used it to build the map. And now we + + + align:start position:0% +we used it to build the map. And now we +have to prove that there's only one A + + align:start position:0% +have to prove that there's only one A + + + align:start position:0% +have to prove that there's only one A +and D that give a certain X and Y here. + + align:start position:0% +and D that give a certain X and Y here. + + + align:start position:0% +and D that give a certain X and Y here. +Okay. So how do we recover them? Well, + + align:start position:0% +Okay. So how do we recover them? Well, + + + align:start position:0% +Okay. So how do we recover them? Well, +if you if this is X and this is Y, we + + align:start position:0% +if you if this is X and this is Y, we + + + align:start position:0% +if you if this is X and this is Y, we +see that Y - X is B of D minus C of D, + + align:start position:0% +see that Y - X is B of D minus C of D, + + + align:start position:0% +see that Y - X is B of D minus C of D, +which is D. So that's how we find D. + + align:start position:0% +which is D. So that's how we find D. + + + align:start position:0% +which is D. So that's how we find D. +And once we find D, it's easy to find we + + align:start position:0% +And once we find D, it's easy to find we + + + align:start position:0% +And once we find D, it's easy to find we +once we find D, then we know B of D and + + align:start position:0% +once we find D, then we know B of D and + + + align:start position:0% +once we find D, then we know B of D and +C of D. And now it's easy to find A. Um, + + align:start position:0% +C of D. And now it's easy to find A. Um, + + + align:start position:0% +C of D. And now it's easy to find A. Um, +so uh X uh minus X plus B of D is A. + + align:start position:0% + + + + align:start position:0% + +It's very short. It feels a teeny bit + + align:start position:0% +It's very short. It feels a teeny bit + + + align:start position:0% +It's very short. It feels a teeny bit +like a magic trick to me. + + align:start position:0% +like a magic trick to me. + + + align:start position:0% +like a magic trick to me. +But so on this board and this board we + + align:start position:0% +But so on this board and this board we + + + align:start position:0% +But so on this board and this board we +have seen that if the sum set is small + + align:start position:0% +have seen that if the sum set is small + + + align:start position:0% +have seen that if the sum set is small +then the difference set is also small. + + align:start position:0% + + + + align:start position:0% + +Okay. + + align:start position:0% +Okay. + + + align:start position:0% +Okay. +Yeah. + + align:start position:0% +Yeah. + + + align:start position:0% +Yeah. +uh you + + align:start position:0% +uh you + + + align:start position:0% +uh you +like divide + + align:start position:0% +like divide + + + align:start position:0% +like divide +by * + + align:start position:0% +by * + + + align:start position:0% +by * +you get like something that looks + + align:start position:0% +you get like something that looks + + + align:start position:0% +you get like something that looks +exactly like a triangle + + align:start position:0% +exactly like a triangle + + + align:start position:0% +exactly like a triangle +way. + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% + + + + align:start position:0% + +>> Yeah. Yeah. Okay. So the question is + + align:start position:0% +>> Yeah. Yeah. Okay. So the question is + + + align:start position:0% +>> Yeah. Yeah. Okay. So the question is +it's called Ruse's triangle inequality + + align:start position:0% +it's called Ruse's triangle inequality + + + align:start position:0% +it's called Ruse's triangle inequality +and it sort of looks like if we take the + + align:start position:0% +and it sort of looks like if we take the + + + align:start position:0% +and it sort of looks like if we take the +logarithm and play with this then + + align:start position:0% +logarithm and play with this then + + + align:start position:0% +logarithm and play with this then +something will look like the triangle + + align:start position:0% +something will look like the triangle + + + align:start position:0% +something will look like the triangle +inequality. + + align:start position:0% +inequality. + + + align:start position:0% +inequality. +Um and uh yeah so Russa did have that in + + align:start position:0% +Um and uh yeah so Russa did have that in + + + align:start position:0% +Um and uh yeah so Russa did have that in +mind when he named it that way. So he + + align:start position:0% +mind when he named it that way. So he + + + align:start position:0% +mind when he named it that way. So he +produced a pseudo distance between + + align:start position:0% +produced a pseudo distance between + + + align:start position:0% +produced a pseudo distance between +different sets say you know between A + + align:start position:0% +different sets say you know between A + + + align:start position:0% +different sets say you know between A +and B or B and C or whatever. And this + + align:start position:0% +and B or B and C or whatever. And this + + + align:start position:0% +and B or B and C or whatever. And this +um this translates into saying that the + + align:start position:0% +um this translates into saying that the + + + align:start position:0% +um this translates into saying that the +rud rou pseudo distance obeys the + + align:start position:0% +rud rou pseudo distance obeys the + + + align:start position:0% +rud rou pseudo distance obeys the +triangle inequality. The distance from B + + align:start position:0% +triangle inequality. The distance from B + + + align:start position:0% +triangle inequality. The distance from B +to C is bounded by the distance from A + + align:start position:0% +to C is bounded by the distance from A + + + align:start position:0% +to C is bounded by the distance from A +to B plus the different distance from + + align:start position:0% +to B plus the different distance from + + + align:start position:0% +to B plus the different distance from +from B to A plus the distance from A to + + align:start position:0% +from B to A plus the distance from A to + + + align:start position:0% +from B to A plus the distance from A to +C. + + align:start position:0% +C. + + + align:start position:0% +C. +Um I'm not sure whether that is helpful + + align:start position:0% +Um I'm not sure whether that is helpful + + + align:start position:0% +Um I'm not sure whether that is helpful +or or not. Um it's his pseudo distance + + align:start position:0% +or or not. Um it's his pseudo distance + + + align:start position:0% +or or not. Um it's his pseudo distance +is a little bit funny. Like it's not + + align:start position:0% +is a little bit funny. Like it's not + + + align:start position:0% +is a little bit funny. Like it's not +true that the distance from A to itself + + align:start position:0% +true that the distance from A to itself + + + align:start position:0% +true that the distance from A to itself +is zero. So it's not quite like + + align:start position:0% +is zero. So it's not quite like + + + align:start position:0% +is zero. So it's not quite like +distances that I'm used to. Um so that + + align:start position:0% +distances that I'm used to. Um so that + + + align:start position:0% +distances that I'm used to. Um so that +intuition I don't know may or may not be + + align:start position:0% +intuition I don't know may or may not be + + + align:start position:0% +intuition I don't know may or may not be +helpful. + + align:start position:0% + + + + align:start position:0% + +Um I guess we will see tomorrow that + + align:start position:0% +Um I guess we will see tomorrow that + + + align:start position:0% +Um I guess we will see tomorrow that +sometimes you use this many times like + + align:start position:0% +sometimes you use this many times like + + + align:start position:0% +sometimes you use this many times like +how you know how how would you use the + + align:start position:0% +how you know how how would you use the + + + align:start position:0% +how you know how how would you use the +triangle inequality? Well the distance + + align:start position:0% +triangle inequality? Well the distance + + + align:start position:0% +triangle inequality? Well the distance +from A to Z is bounded by the distance + + align:start position:0% +from A to Z is bounded by the distance + + + align:start position:0% +from A to Z is bounded by the distance +from A to B plus the distance from B to + + align:start position:0% +from A to B plus the distance from B to + + + align:start position:0% +from A to B plus the distance from B to +C plus the distance from C to D D D D D + + align:start position:0% +C plus the distance from C to D D D D D + + + align:start position:0% +C plus the distance from C to D D D D D +D D D D D D D D D D D D D D D D D D D D + + align:start position:0% +D D D D D D D D D D D D D D D D D D D D + + + align:start position:0% +D D D D D D D D D D D D D D D D D D D D +D D D D D D D D D D D D D D D D D D D D + + align:start position:0% +D D D D D D D D D D D D D D D D D D D D + + + align:start position:0% +D D D D D D D D D D D D D D D D D D D D +D D D D D D D D D D D D D D D D and + + align:start position:0% +D D D D D D D D D D D D D D D D and + + + align:start position:0% +D D D D D D D D D D D D D D D D and +maybe each of those things is easier to + + align:start position:0% +maybe each of those things is easier to + + + align:start position:0% +maybe each of those things is easier to +understand and by the triangle + + align:start position:0% +understand and by the triangle + + + align:start position:0% +understand and by the triangle +inequality, we can put them together. So + + align:start position:0% +inequality, we can put them together. So + + + align:start position:0% +inequality, we can put them together. So +you can use this inequality in that way. + + align:start position:0% +you can use this inequality in that way. + + + align:start position:0% +you can use this inequality in that way. +Um, and we'll see that tomorrow. + + align:start position:0% +Um, and we'll see that tomorrow. + + + align:start position:0% +Um, and we'll see that tomorrow. +Tomorrow, Thursday. + + align:start position:0% +Tomorrow, Thursday. + + + align:start position:0% +Tomorrow, Thursday. +Any other questions or comments? + + align:start position:0% + + + + align:start position:0% + +>> Can I ask about the previous removing + + align:start position:0% +>> Can I ask about the previous removing + + + align:start position:0% +>> Can I ask about the previous removing +denominator? + + align:start position:0% + + + + align:start position:0% + +Just not sure how that works out. Does + + align:start position:0% +Just not sure how that works out. Does + + + align:start position:0% +Just not sure how that works out. Does +it require something like this? + + align:start position:0% +it require something like this? + + + align:start position:0% +it require something like this? +Um the question is about the removing + + align:start position:0% +Um the question is about the removing + + + align:start position:0% +Um the question is about the removing +the denominator trick. + + align:start position:0% + + + + align:start position:0% + +>> Um like when we had we had an a minus a + + align:start position:0% +>> Um like when we had we had an a minus a + + + align:start position:0% +>> Um like when we had we had an a minus a +in the denominator and we multiplied it + + align:start position:0% +in the denominator and we multiplied it + + + align:start position:0% +in the denominator and we multiplied it +out. + + align:start position:0% +out. + + + align:start position:0% +out. +>> So that that was just um + + align:start position:0% +>> So that that was just um + + + align:start position:0% +>> So that that was just um +algebra. + + align:start position:0% + + + + align:start position:0% + +Um it's not it's not something fancy + + align:start position:0% +Um it's not it's not something fancy + + + align:start position:0% +Um it's not it's not something fancy +like this. + + align:start position:0% +like this. + + + align:start position:0% +like this. +Um + + align:start position:0% +Um + + + align:start position:0% +Um +we'll u yeah let me bracket that we'll + + align:start position:0% +we'll u yeah let me bracket that we'll + + + align:start position:0% +we'll u yeah let me bracket that we'll +see a little later something else with + + align:start position:0% +see a little later something else with + + + align:start position:0% +see a little later something else with +removing denominators and and let's come + + align:start position:0% +removing denominators and and let's come + + + align:start position:0% +removing denominators and and let's come +back to it then + + align:start position:0% + + + + align:start position:0% + +do do you think did I understand your + + align:start position:0% +do do you think did I understand your + + + align:start position:0% +do do you think did I understand your +question or + + align:start position:0% +question or + + + align:start position:0% +question or +>> yeah I'm just not sure how that how how + + align:start position:0% +>> yeah I'm just not sure how that how how + + + align:start position:0% +>> yeah I'm just not sure how that how how +that was actually + + align:start position:0% +that was actually + + + align:start position:0% +that was actually +>> I think you only need six instead of + + align:start position:0% +>> I think you only need six instead of + + + align:start position:0% +>> I think you only need six instead of +eight + + align:start position:0% +eight + + + align:start position:0% +eight +Yeah, let's check in about it at the end + + align:start position:0% +Yeah, let's check in about it at the end + + + align:start position:0% +Yeah, let's check in about it at the end +of class. Okay, the other important um + + align:start position:0% +of class. Okay, the other important um + + + align:start position:0% +of class. Okay, the other important um +lema from from this field that went into + + align:start position:0% +lema from from this field that went into + + + align:start position:0% +lema from from this field that went into +the proof of framan's theorem is called + + align:start position:0% +the proof of framan's theorem is called + + + align:start position:0% +the proof of framan's theorem is called +Plunka inequality. + + align:start position:0% + + + + align:start position:0% + +Plunka inequality allows us to say + + align:start position:0% +Plunka inequality allows us to say + + + align:start position:0% +Plunka inequality allows us to say +things like if a plus a is small then a + + align:start position:0% +things like if a plus a is small then a + + + align:start position:0% +things like if a plus a is small then a +plus a plus a is small. + + align:start position:0% + + + + align:start position:0% + +So if A and B are subsets of Z in a + + align:start position:0% +So if A and B are subsets of Z in a + + + align:start position:0% +So if A and B are subsets of Z in a +billion group + + align:start position:0% + + + + align:start position:0% + +um and A + B is bounded by K * A + + align:start position:0% +um and A + B is bounded by K * A + + + align:start position:0% +um and A + B is bounded by K * A +then + + align:start position:0% +then + + + align:start position:0% +then +um okay let me make a little notation. + + align:start position:0% +um okay let me make a little notation. + + + align:start position:0% +um okay let me make a little notation. +So sometimes we might want to talk about + + align:start position:0% +So sometimes we might want to talk about + + + align:start position:0% +So sometimes we might want to talk about +b + b many times + + align:start position:0% +b + b many times + + + align:start position:0% +b + b many times +um so let's say this is n times this is + + align:start position:0% +um so let's say this is n times this is + + + align:start position:0% +um so let's say this is n times this is +sometimes written as n * b um although I + + align:start position:0% +sometimes written as n * b um although I + + + align:start position:0% +sometimes written as n * b um although I +feel like that is slightly confusing um + + align:start position:0% +feel like that is slightly confusing um + + + align:start position:0% +feel like that is slightly confusing um +so I have decided to adopt this notation + + align:start position:0% +so I have decided to adopt this notation + + + align:start position:0% +so I have decided to adopt this notation +b like sum n times + + align:start position:0% + + + + align:start position:0% + +okay so I could take b + m * - b + n * + + align:start position:0% +okay so I could take b + m * - b + n * + + + align:start position:0% +okay so I could take b + m * - b + n * +and that's bounded by k to the m + n * + + align:start position:0% + + + + align:start position:0% + +okay so let's do a few corlaries of this + + align:start position:0% +okay so let's do a few corlaries of this + + + align:start position:0% +okay so let's do a few corlaries of this +um so just by plugging in a equals b we + + align:start position:0% +um so just by plugging in a equals b we + + + align:start position:0% +um so just by plugging in a equals b we +see that if a + a is less than or equal + + align:start position:0% +see that if a + a is less than or equal + + + align:start position:0% +see that if a + a is less than or equal +to k a um then a minus a is less less + + align:start position:0% +to k a um then a minus a is less less + + + align:start position:0% +to k a um then a minus a is less less +than k^ 2 a. Uh that's actually the + + align:start position:0% +than k^ 2 a. Uh that's actually the + + + align:start position:0% +than k^ 2 a. Uh that's actually the +correlary we already proved. Um but also + + align:start position:0% +correlary we already proved. Um but also + + + align:start position:0% +correlary we already proved. Um but also +we could say a + a + a is bounded by k + + align:start position:0% +we could say a + a + a is bounded by k + + + align:start position:0% +we could say a + a + a is bounded by k +cubed a + + align:start position:0% + + + + align:start position:0% + +uh just plugging in a b and this is m is + + align:start position:0% +uh just plugging in a b and this is m is + + + align:start position:0% +uh just plugging in a b and this is m is +three and n is zero and you can see you + + align:start position:0% +three and n is zero and you can see you + + + align:start position:0% +three and n is zero and you can see you +can put higher powers here. + + align:start position:0% +can put higher powers here. + + + align:start position:0% +can put higher powers here. +Also another corlary we can get is we + + align:start position:0% +Also another corlary we can get is we + + + align:start position:0% +Also another corlary we can get is we +can switch the role of these guys in the + + align:start position:0% +can switch the role of these guys in the + + + align:start position:0% +can switch the role of these guys in the +first corlary. So we can say if a minus + + align:start position:0% +first corlary. So we can say if a minus + + + align:start position:0% +first corlary. So we can say if a minus +a is small + + align:start position:0% + + + + align:start position:0% + +then a a plus a is also small. + + align:start position:0% + + + + align:start position:0% + +So + + align:start position:0% +So + + + align:start position:0% +So +proof is that b is negative a. So this + + align:start position:0% +proof is that b is negative a. So this + + + align:start position:0% +proof is that b is negative a. So this +is a plus b and then this is basically b + + align:start position:0% +is a plus b and then this is basically b + + + align:start position:0% +is a plus b and then this is basically b +plus b. + + align:start position:0% + + + + align:start position:0% + +Okay. + + align:start position:0% + + + + align:start position:0% + +Okay. Um, + + align:start position:0% +Okay. Um, + + + align:start position:0% +Okay. Um, +we can also use this. So, we'll prove + + align:start position:0% +we can also use this. So, we'll prove + + + align:start position:0% +we can also use this. So, we'll prove +this. That'll be our last big goal of + + align:start position:0% +this. That'll be our last big goal of + + + align:start position:0% +this. That'll be our last big goal of +the class. Um but using + + align:start position:0% +the class. Um but using + + + align:start position:0% +the class. Um but using +so this rera inequality and plunic + + align:start position:0% +so this rera inequality and plunic + + + align:start position:0% +so this rera inequality and plunic +inequality have many many uses and one + + align:start position:0% +inequality have many many uses and one + + + align:start position:0% +inequality have many many uses and one +simple use is we can use it to sort of + + align:start position:0% +simple use is we can use it to sort of + + + align:start position:0% +simple use is we can use it to sort of +clean up and improve the statement of + + align:start position:0% +clean up and improve the statement of + + + align:start position:0% +clean up and improve the statement of +our lema that fp if that has no + + align:start position:0% +our lema that fp if that has no + + + align:start position:0% +our lema that fp if that has no +quantitative approximate sub fields. So + + align:start position:0% +quantitative approximate sub fields. So + + + align:start position:0% +quantitative approximate sub fields. So +let me recall what we proved so far and + + align:start position:0% +let me recall what we proved so far and + + + align:start position:0% +let me recall what we proved so far and +then we'll improve it a little bit. + + align:start position:0% + + + + align:start position:0% + +Um so lma one was uh + + align:start position:0% +Um so lma one was uh + + + align:start position:0% +Um so lma one was uh +if a is in fp + + align:start position:0% +if a is in fp + + + align:start position:0% +if a is in fp +then either + + align:start position:0% + + + + align:start position:0% + +um + + align:start position:0% +um + + + align:start position:0% +um +a minus a over a minus a is all of fp + + align:start position:0% + + + + align:start position:0% + +or + + align:start position:0% +or + + + align:start position:0% +or +uh a * a min - a * A. + + align:start position:0% +uh a * a min - a * A. + + + align:start position:0% +uh a * a min - a * A. +Okay. So now I can write this better. We + + align:start position:0% +Okay. So now I can write this better. We + + + align:start position:0% +Okay. So now I can write this better. We +have three or four of those + + align:start position:0% +have three or four of those + + + align:start position:0% +have three or four of those +minus three or four of those + + align:start position:0% +minus three or four of those + + + align:start position:0% +minus three or four of those +as it is. + + align:start position:0% +as it is. + + + align:start position:0% +as it is. +Okay. So we can improve this in a way + + align:start position:0% +Okay. So we can improve this in a way + + + align:start position:0% +Okay. So we can improve this in a way +that you don't need to have so many + + align:start position:0% +that you don't need to have so many + + + align:start position:0% +that you don't need to have so many +different expressions floating around. + + align:start position:0% +different expressions floating around. + + + align:start position:0% +different expressions floating around. +So we can say that if a is in fp + + align:start position:0% +So we can say that if a is in fp + + + align:start position:0% +So we can say that if a is in fp +and the size of a is p to the s where s + + align:start position:0% +and the size of a is p to the s where s + + + align:start position:0% +and the size of a is p to the s where s +is strictly less than one then the size + + align:start position:0% +is strictly less than one then the size + + + align:start position:0% +is strictly less than one then the size +of a * a minus a * a is at least p to + + align:start position:0% +of a * a minus a * a is at least p to + + + align:start position:0% +of a * a minus a * a is at least p to +the s plus epsilon of s. + + align:start position:0% +the s plus epsilon of s. + + + align:start position:0% +the s plus epsilon of s. +And here you could you could put either + + align:start position:0% +And here you could you could put either + + + align:start position:0% +And here you could you could put either +plus or minus. + + align:start position:0% + + + + align:start position:0% + +And this epsilon of s is bigger than + + align:start position:0% +And this epsilon of s is bigger than + + + align:start position:0% +And this epsilon of s is bigger than +zero. + + align:start position:0% +zero. + + + align:start position:0% +zero. +So again it's continuous it's explicit + + align:start position:0% +So again it's continuous it's explicit + + + align:start position:0% +So again it's continuous it's explicit +but it's a little bit messy and it's + + align:start position:0% +but it's a little bit messy and it's + + + align:start position:0% +but it's a little bit messy and it's +it's a little bit small. + + align:start position:0% +it's a little bit small. + + + align:start position:0% +it's a little bit small. +You take any subset which is + + align:start position:0% +You take any subset which is + + + align:start position:0% +You take any subset which is +significantly smaller than the whole + + align:start position:0% +significantly smaller than the whole + + + align:start position:0% +significantly smaller than the whole +field. If you do take a * a minus a * a + + align:start position:0% +field. If you do take a * a minus a * a + + + align:start position:0% +field. If you do take a * a minus a * a +it will be significantly bigger than you + + align:start position:0% +it will be significantly bigger than you + + + align:start position:0% +it will be significantly bigger than you +started with. + + align:start position:0% + + + + align:start position:0% + +So, you know, if you just took a minus + + align:start position:0% +So, you know, if you just took a minus + + + align:start position:0% +So, you know, if you just took a minus +a, that wouldn't be good enough because + + align:start position:0% +a, that wouldn't be good enough because + + + align:start position:0% +a, that wouldn't be good enough because +a could be an arithmetic progression. It + + align:start position:0% +a could be an arithmetic progression. It + + + align:start position:0% +a could be an arithmetic progression. It +might so that might have almost the same + + align:start position:0% +might so that might have almost the same + + + align:start position:0% +might so that might have almost the same +size as a. If you just took a time a + + align:start position:0% +size as a. If you just took a time a + + + align:start position:0% +size as a. If you just took a time a +that wouldn't be good enough because a + + align:start position:0% +that wouldn't be good enough because a + + + align:start position:0% +that wouldn't be good enough because a +could be a geometric progression. Two 2 + + align:start position:0% +could be a geometric progression. Two 2 + + + align:start position:0% +could be a geometric progression. Two 2 +1 2 the 2 up to 2 to the l. + + align:start position:0% +1 2 the 2 up to 2 to the l. + + + align:start position:0% +1 2 the 2 up to 2 to the l. +Um, but if you take both sums and + + align:start position:0% +Um, but if you take both sums and + + + align:start position:0% +Um, but if you take both sums and +products, then you have to end up with + + align:start position:0% +products, then you have to end up with + + + align:start position:0% +products, then you have to end up with +significantly more stuff than you + + align:start position:0% +significantly more stuff than you + + + align:start position:0% +significantly more stuff than you +started with. Okay, so that's why this + + align:start position:0% +started with. Okay, so that's why this + + + align:start position:0% +started with. Okay, so that's why this +is called sum product theory. If you + + align:start position:0% +is called sum product theory. If you + + + align:start position:0% +is called sum product theory. If you +have both sums and products interacting + + align:start position:0% +have both sums and products interacting + + + align:start position:0% +have both sums and products interacting +with each other, then something happens. + + align:start position:0% +with each other, then something happens. + + + align:start position:0% +with each other, then something happens. +Okay, so uh proof + + align:start position:0% +Okay, so uh proof + + + align:start position:0% +Okay, so uh proof +um + + align:start position:0% +um + + + align:start position:0% +um +okay so if + + align:start position:0% +okay so if + + + align:start position:0% +okay so if +um + + align:start position:0% +um + + + align:start position:0% +um +okay so there there are two cases case + + align:start position:0% +okay so there there are two cases case + + + align:start position:0% +okay so there there are two cases case +one and case two but I'm actually going + + align:start position:0% +one and case two but I'm actually going + + + align:start position:0% +one and case two but I'm actually going +to do case two first. + + align:start position:0% +to do case two first. + + + align:start position:0% +to do case two first. +So case + + align:start position:0% +So case + + + align:start position:0% +So case +um + + align:start position:0% + + + + align:start position:0% + +okay so it could be that a * a is + + align:start position:0% +okay so it could be that a * a is + + + align:start position:0% +okay so it could be that a * a is +already much bigger than a then we just + + align:start position:0% +already much bigger than a then we just + + + align:start position:0% +already much bigger than a then we just +declare victory. So if + + align:start position:0% +declare victory. So if + + + align:start position:0% +declare victory. So if +a * a is bigger than a to the 1 + delta + + align:start position:0% +a * a is bigger than a to the 1 + delta + + + align:start position:0% +a * a is bigger than a to the 1 + delta +then we declare victory and here delta + + align:start position:0% +then we declare victory and here delta + + + align:start position:0% +then we declare victory and here delta +is going to be much smaller than epsilon + + align:start position:0% + + + + align:start position:0% + +um + + align:start position:0% +um + + + align:start position:0% +um +or maybe we could say okay otherwise + + align:start position:0% + + + + align:start position:0% + +otherwise + + align:start position:0% +otherwise + + + align:start position:0% +otherwise +um + + align:start position:0% + + + + align:start position:0% + +uh otherwise a * a is basically the same + + align:start position:0% +uh otherwise a * a is basically the same + + + align:start position:0% +uh otherwise a * a is basically the same +size as a. + + align:start position:0% +size as a. + + + align:start position:0% +size as a. +Okay. Now, if a * a um plus a * a is + + align:start position:0% +Okay. Now, if a * a um plus a * a is + + + align:start position:0% +Okay. Now, if a * a um plus a * a is +much bigger than a, then we declare + + align:start position:0% +much bigger than a, then we declare + + + align:start position:0% +much bigger than a, then we declare +victory. + + align:start position:0% + + + + align:start position:0% + +Uh where is I writing? Yeah, here. I + + align:start position:0% +Uh where is I writing? Yeah, here. I + + + align:start position:0% +Uh where is I writing? Yeah, here. I +guess let's just put this + + align:start position:0% + + + + align:start position:0% + +and we declare victory. Um otherwise + + align:start position:0% + + + + align:start position:0% + +we would have a * a + a * a is smaller + + align:start position:0% +we would have a * a + a * a is smaller + + + align:start position:0% +we would have a * a + a * a is smaller +than k a * a where k is like uh p to the + + align:start position:0% +than k a * a where k is like uh p to the + + + align:start position:0% +than k a * a where k is like uh p to the +epsilon + + align:start position:0% +epsilon + + + align:start position:0% +epsilon +and then we can use plunker + + align:start position:0% + + + + align:start position:0% + +and that would tell us that a * a to a + + align:start position:0% +and that would tell us that a * a to a + + + align:start position:0% +and that would tell us that a * a to a +big power + + align:start position:0% +big power + + + align:start position:0% +big power +minus a * a to another big power + + align:start position:0% +minus a * a to another big power + + + align:start position:0% +minus a * a to another big power +here. We could put + + align:start position:0% +here. We could put + + + align:start position:0% +here. We could put +four. Um that would be bounded by k to + + align:start position:0% +four. Um that would be bounded by k to + + + align:start position:0% +four. Um that would be bounded by k to +the eth a * a. + + align:start position:0% +the eth a * a. + + + align:start position:0% +the eth a * a. +Um and so that would be bounded by maybe + + align:start position:0% +Um and so that would be bounded by maybe + + + align:start position:0% +Um and so that would be bounded by maybe +um a * p to the tan epsilon or something + + align:start position:0% +um a * p to the tan epsilon or something + + + align:start position:0% +um a * p to the tan epsilon or something +like that. And this contradicts the fact + + align:start position:0% +like that. And this contradicts the fact + + + align:start position:0% +like that. And this contradicts the fact +that this we know this set is bigger. + + align:start position:0% + + + + align:start position:0% + +Okay. And case one is similar but I + + align:start position:0% +Okay. And case one is similar but I + + + align:start position:0% +Okay. And case one is similar but I +think maybe I'll make that an exercise. + + align:start position:0% +think maybe I'll make that an exercise. + + + align:start position:0% +think maybe I'll make that an exercise. +You can just practice using pluna and + + align:start position:0% +You can just practice using pluna and + + + align:start position:0% +You can just practice using pluna and +rua things. + + align:start position:0% + + + + align:start position:0% + +Okay. And I'm going to do one more + + align:start position:0% +Okay. And I'm going to do one more + + + align:start position:0% +Okay. And I'm going to do one more +correlary. Um so suppose you you know + + align:start position:0% +correlary. Um so suppose you you know + + + align:start position:0% +correlary. Um so suppose you you know +you start with the set A and you start + + align:start position:0% +you start with the set A and you start + + + align:start position:0% +you start with the set A and you start +multiplying and adding and subtracting + + align:start position:0% +multiplying and adding and subtracting + + + align:start position:0% +multiplying and adding and subtracting +and see what you get and we've proven + + align:start position:0% +and see what you get and we've proven + + + align:start position:0% +and see what you get and we've proven +that after you do after you do this + + align:start position:0% +that after you do after you do this + + + align:start position:0% +that after you do after you do this +operation it gets a bit bigger + + align:start position:0% +operation it gets a bit bigger + + + align:start position:0% +operation it gets a bit bigger +but suppose you don't just yeah + + align:start position:0% +but suppose you don't just yeah + + + align:start position:0% +but suppose you don't just yeah +>> one question about this so you said that + + align:start position:0% +>> one question about this so you said that + + + align:start position:0% +>> one question about this so you said that +kind of the idea is that if you have + + align:start position:0% +kind of the idea is that if you have + + + align:start position:0% +kind of the idea is that if you have +sort of arithmetic progression or + + align:start position:0% +sort of arithmetic progression or + + + align:start position:0% +sort of arithmetic progression or +geometric progression it can be small + + align:start position:0% +geometric progression it can be small + + + align:start position:0% +geometric progression it can be small +but with both it has to be large. Is it + + align:start position:0% +but with both it has to be large. Is it + + + align:start position:0% +but with both it has to be large. Is it +possible to prove that instead of the + + align:start position:0% +possible to prove that instead of the + + + align:start position:0% +possible to prove that instead of the +the difference of a * a and a * a you + + align:start position:0% +the difference of a * a and a * a you + + + align:start position:0% +the difference of a * a and a * a you +can just say a * a is large or a plus a + + align:start position:0% +can just say a * a is large or a plus a + + + align:start position:0% +can just say a * a is large or a plus a +is large. + + align:start position:0% +is large. + + + align:start position:0% +is large. +>> Okay. Yes. Great question. Okay. So the + + align:start position:0% +>> Okay. Yes. Great question. Okay. So the + + + align:start position:0% +>> Okay. Yes. Great question. Okay. So the +question is so so in the theme of lema 2 + + align:start position:0% +question is so so in the theme of lema 2 + + + align:start position:0% +question is so so in the theme of lema 2 +is we tried to simplify as much as + + align:start position:0% +is we tried to simplify as much as + + + align:start position:0% +is we tried to simplify as much as +possible the expression that we put here + + align:start position:0% +possible the expression that we put here + + + align:start position:0% +possible the expression that we put here +and there is a suggestion um how to make + + align:start position:0% +and there is a suggestion um how to make + + + align:start position:0% +and there is a suggestion um how to make +it as simple as possible. Um, so let me + + align:start position:0% +it as simple as possible. Um, so let me + + + align:start position:0% +it as simple as possible. Um, so let me +I'm going to erase this proof and write + + align:start position:0% +I'm going to erase this proof and write + + + align:start position:0% +I'm going to erase this proof and write +that as a as a I'll write it as a + + align:start position:0% +that as a as a I'll write it as a + + + align:start position:0% +that as a as a I'll write it as a +theorem. It's a theorem. + + align:start position:0% +theorem. It's a theorem. + + + align:start position:0% +theorem. It's a theorem. +So + + align:start position:0% +So + + + align:start position:0% +So +even better + + align:start position:0% + + + + align:start position:0% + +there is a theorem + + align:start position:0% +there is a theorem + + + align:start position:0% +there is a theorem +um ban cat's towel. + + align:start position:0% +um ban cat's towel. + + + align:start position:0% +um ban cat's towel. +So if a is subset of fp + + align:start position:0% +So if a is subset of fp + + + align:start position:0% +So if a is subset of fp +uh a equ= p to the s0 less than or equal + + align:start position:0% +uh a equ= p to the s0 less than or equal + + + align:start position:0% +uh a equ= p to the s0 less than or equal +to s less than 1 then + + align:start position:0% +to s less than 1 then + + + align:start position:0% +to s less than 1 then +you could take um the maximum + + align:start position:0% +you could take um the maximum + + + align:start position:0% +you could take um the maximum +of a + a and a * a + + align:start position:0% +of a + a and a * a + + + align:start position:0% +of a + a and a * a +and that is bigger than p to the s plus + + align:start position:0% +and that is bigger than p to the s plus + + + align:start position:0% +and that is bigger than p to the s plus +epsilon of s. + + align:start position:0% +epsilon of s. + + + align:start position:0% +epsilon of s. +So this is better than this + + align:start position:0% +So this is better than this + + + align:start position:0% +So this is better than this +qualitatively. + + align:start position:0% + + + + align:start position:0% + +And actually the word sum product + + align:start position:0% +And actually the word sum product + + + align:start position:0% +And actually the word sum product +inequality it could refer to a lot of + + align:start position:0% +inequality it could refer to a lot of + + + align:start position:0% +inequality it could refer to a lot of +things but the the the inequality it + + align:start position:0% +things but the the the inequality it + + + align:start position:0% +things but the the the inequality it +most often refers to is this one. So + + align:start position:0% +most often refers to is this one. So + + + align:start position:0% +most often refers to is this one. So +either either the sums or the products + + align:start position:0% +either either the sums or the products + + + align:start position:0% +either either the sums or the products +grow. Yeah, that's right. Okay. So all + + align:start position:0% +grow. Yeah, that's right. Okay. So all + + + align:start position:0% +grow. Yeah, that's right. Okay. So all +the stuff we've seen are steps towards + + align:start position:0% +the stuff we've seen are steps towards + + + align:start position:0% +the stuff we've seen are steps towards +the proof of this theorem. But there is + + align:start position:0% +the proof of this theorem. But there is + + + align:start position:0% +the proof of this theorem. But there is +actually still some more ideas to get + + align:start position:0% +actually still some more ideas to get + + + align:start position:0% +actually still some more ideas to get +all the way down to here. And we may or + + align:start position:0% +all the way down to here. And we may or + + + align:start position:0% +all the way down to here. And we may or +may not end up doing it in the class. + + align:start position:0% +may not end up doing it in the class. + + + align:start position:0% +may not end up doing it in the class. +It's unclear to me if getting all the + + align:start position:0% +It's unclear to me if getting all the + + + align:start position:0% +It's unclear to me if getting all the +way down to there is actually uh + + align:start position:0% +way down to there is actually uh + + + align:start position:0% +way down to there is actually uh +important in in projection theory. + + align:start position:0% +important in in projection theory. + + + align:start position:0% +important in in projection theory. +Yeah. Cool. + + align:start position:0% +Yeah. Cool. + + + align:start position:0% +Yeah. Cool. +Okay. So, one goal you might have in in + + align:start position:0% +Okay. So, one goal you might have in in + + + align:start position:0% +Okay. So, one goal you might have in in +in simplifying and clarifying this story + + align:start position:0% +in simplifying and clarifying this story + + + align:start position:0% +in simplifying and clarifying this story +is to make this expression as simple as + + align:start position:0% +is to make this expression as simple as + + + align:start position:0% +is to make this expression as simple as +possible and get some gain. But another + + align:start position:0% +possible and get some gain. But another + + + align:start position:0% +possible and get some gain. But another +goal that you might have is to make this + + align:start position:0% +goal that you might have is to make this + + + align:start position:0% +goal that you might have is to make this +gain really large and perhaps this + + align:start position:0% +gain really large and perhaps this + + + align:start position:0% +gain really large and perhaps this +expression will be more complicated and + + align:start position:0% +expression will be more complicated and + + + align:start position:0% +expression will be more complicated and +you can also do that. + + align:start position:0% +you can also do that. + + + align:start position:0% +you can also do that. +So let me make some uh notation. + + align:start position:0% + + + + align:start position:0% + +Let's say poly k of a some sort of + + align:start position:0% +Let's say poly k of a some sort of + + + align:start position:0% +Let's say poly k of a some sort of +polomials of complexity k. So I take a + + align:start position:0% +polomials of complexity k. So I take a + + + align:start position:0% +polomials of complexity k. So I take a +to the k. So that's means I multiply + + align:start position:0% +to the k. So that's means I multiply + + + align:start position:0% +to the k. So that's means I multiply +uh k different elements of a together + + align:start position:0% +uh k different elements of a together + + + align:start position:0% +uh k different elements of a together +and then I add k things like that + + align:start position:0% +and then I add k things like that + + + align:start position:0% +and then I add k things like that +together and then maybe I also want some + + align:start position:0% +together and then maybe I also want some + + + align:start position:0% +together and then maybe I also want some +minuses + + align:start position:0% + + + + align:start position:0% + +right so a a to the k is a * a * a k * + + align:start position:0% + + + + align:start position:0% + +okay so these are polomials in A of + + align:start position:0% +okay so these are polomials in A of + + + align:start position:0% +okay so these are polomials in A of +complexity + + align:start position:0% +complexity + + + align:start position:0% +complexity +and uh another corlary which is at the + + align:start position:0% +and uh another corlary which is at the + + + align:start position:0% +and uh another corlary which is at the +same level follows easily from this one + + align:start position:0% +same level follows easily from this one + + + align:start position:0% +same level follows easily from this one +is that if we have zero less than s less + + align:start position:0% +is that if we have zero less than s less + + + align:start position:0% +is that if we have zero less than s less +than t less than one and a is in fp. So + + align:start position:0% +than t less than one and a is in fp. So + + + align:start position:0% +than t less than one and a is in fp. So +okay then there exists some k that only + + align:start position:0% +okay then there exists some k that only + + + align:start position:0% +okay then there exists some k that only +depends on s and t. So that for any set + + align:start position:0% +depends on s and t. So that for any set + + + align:start position:0% +depends on s and t. So that for any set +A in any FP where the size of A is P to + + align:start position:0% +A in any FP where the size of A is P to + + + align:start position:0% +A in any FP where the size of A is P to +the S, the size of poly K of A + + align:start position:0% +the S, the size of poly K of A + + + align:start position:0% +the S, the size of poly K of A +is at least P to the T. + + align:start position:0% + + + + align:start position:0% + +Okay. And the proof of this is is easy. + + align:start position:0% +Okay. And the proof of this is is easy. + + + align:start position:0% +Okay. And the proof of this is is easy. +The proof is use lema too many times. + + align:start position:0% + + + + align:start position:0% + +So I start with the set A. A * A minus A + + align:start position:0% +So I start with the set A. A * A minus A + + + align:start position:0% +So I start with the set A. A * A minus A +* A is a bit bigger. Called this B. B * + + align:start position:0% +* A is a bit bigger. Called this B. B * + + + align:start position:0% +* A is a bit bigger. Called this B. B * +B minus B * B is even a bit bigger. + + align:start position:0% +B minus B * B is even a bit bigger. + + + align:start position:0% +B minus B * B is even a bit bigger. +And if you think about what B * B minus + + align:start position:0% +And if you think about what B * B minus + + + align:start position:0% +And if you think about what B * B minus +B * B means, it would fit in like + + align:start position:0% +B * B means, it would fit in like + + + align:start position:0% +B * B means, it would fit in like +probably four again. + + align:start position:0% +probably four again. + + + align:start position:0% +probably four again. +And you keep doing this. + + align:start position:0% + + + + align:start position:0% + +Okay, cool. + + align:start position:0% +Okay, cool. + + + align:start position:0% +Okay, cool. +Cool. + + align:start position:0% +Cool. + + + align:start position:0% +Cool. +Um so these these lemas theorems and + + align:start position:0% +Um so these these lemas theorems and + + + align:start position:0% +Um so these these lemas theorems and +stuff they are important because um + + align:start position:0% +stuff they are important because um + + + align:start position:0% +stuff they are important because um +and plumac's inequality and ruse's + + align:start position:0% +and plumac's inequality and ruse's + + + align:start position:0% +and plumac's inequality and ruse's +inequality they are important + + align:start position:0% +inequality they are important + + + align:start position:0% +inequality they are important +um because um + + align:start position:0% +um because um + + + align:start position:0% +um because um +you so once we once we see so if we see + + align:start position:0% +you so once we once we see so if we see + + + align:start position:0% +you so once we once we see so if we see +something like a plus a is small that + + align:start position:0% +something like a plus a is small that + + + align:start position:0% +something like a plus a is small that +then that tells us that a has some + + align:start position:0% +then that tells us that a has some + + + align:start position:0% +then that tells us that a has some +structure and all these inequalities + + align:start position:0% +structure and all these inequalities + + + align:start position:0% +structure and all these inequalities +then imply that lots of other things are + + align:start position:0% +then imply that lots of other things are + + + align:start position:0% +then imply that lots of other things are +small. So it's sort of like a contagious + + align:start position:0% +small. So it's sort of like a contagious + + + align:start position:0% +small. So it's sort of like a contagious +structure like we start we input some + + align:start position:0% +structure like we start we input some + + + align:start position:0% +structure like we start we input some +structure but we find out more and more + + align:start position:0% +structure but we find out more and more + + + align:start position:0% +structure but we find out more and more +structure and that's a very useful tool + + align:start position:0% +structure and that's a very useful tool + + + align:start position:0% +structure and that's a very useful tool +and so lots of problems that we see in + + align:start position:0% +and so lots of problems that we see in + + + align:start position:0% +and so lots of problems that we see in +projection theory uh it seems to be + + align:start position:0% +projection theory uh it seems to be + + + align:start position:0% +projection theory uh it seems to be +helpful to try to phrase them in the + + align:start position:0% +helpful to try to phrase them in the + + + align:start position:0% +helpful to try to phrase them in the +form that some subset is small because + + align:start position:0% +form that some subset is small because + + + align:start position:0% +form that some subset is small because +then we can use Pluna's inequality and + + align:start position:0% +then we can use Pluna's inequality and + + + align:start position:0% +then we can use Pluna's inequality and +we can find out lots of other things. + + align:start position:0% + + + + align:start position:0% + +Okay. So in the last part of the class + + align:start position:0% +Okay. So in the last part of the class + + + align:start position:0% +Okay. So in the last part of the class +we will prove this inequality. This is + + align:start position:0% +we will prove this inequality. This is + + + align:start position:0% +we will prove this inequality. This is +the trickiest thing that we will prove + + align:start position:0% +the trickiest thing that we will prove + + + align:start position:0% +the trickiest thing that we will prove +today. + + align:start position:0% + + + + align:start position:0% + +All right. So the original proof of the + + align:start position:0% +All right. So the original proof of the + + + align:start position:0% +All right. So the original proof of the +pluna inequality was somewhat difficult. + + align:start position:0% +pluna inequality was somewhat difficult. + + + align:start position:0% +pluna inequality was somewhat difficult. +Um and there was a short proof that was + + align:start position:0% +Um and there was a short proof that was + + + align:start position:0% +Um and there was a short proof that was +given by Jorgus Petritus + + align:start position:0% +given by Jorgus Petritus + + + align:start position:0% +given by Jorgus Petritus +um about 10 or 15 years ago which is the + + align:start position:0% +um about 10 or 15 years ago which is the + + + align:start position:0% +um about 10 or 15 years ago which is the +one that I'll that I'll show. + + align:start position:0% +one that I'll that I'll show. + + + align:start position:0% +one that I'll that I'll show. +Okay. + + align:start position:0% + + + + align:start position:0% + +So it's based on a key lema. + + align:start position:0% + + + + align:start position:0% + +So the key lema says that if a + b is at + + align:start position:0% +So the key lema says that if a + b is at + + + align:start position:0% +So the key lema says that if a + b is at +most k * a + + align:start position:0% +most k * a + + + align:start position:0% +most k * a +then there's a subset x contained in a + + align:start position:0% +then there's a subset x contained in a + + + align:start position:0% +then there's a subset x contained in a +so that for any set c + + align:start position:0% +so that for any set c + + + align:start position:0% +so that for any set c +x + c + b + + align:start position:0% +x + c + b + + + align:start position:0% +x + c + b +divided by x + c is also at most k. + + align:start position:0% + + + + align:start position:0% + +So okay by the way this top inequality + + align:start position:0% +So okay by the way this top inequality + + + align:start position:0% +So okay by the way this top inequality +of course we can divide by a. The top + + align:start position:0% +of course we can divide by a. The top + + + align:start position:0% +of course we can divide by a. The top +inequality says a + b over a is bounded + + align:start position:0% +inequality says a + b over a is bounded + + + align:start position:0% +inequality says a + b over a is bounded +by k. + + align:start position:0% +by k. + + + align:start position:0% +by k. +The lema says that if this is true + + align:start position:0% +The lema says that if this is true + + + align:start position:0% +The lema says that if this is true +then it's so if it's true for the set a + + align:start position:0% +then it's so if it's true for the set a + + + align:start position:0% +then it's so if it's true for the set a +then it's also true for the set x plus c + + align:start position:0% +then it's also true for the set x plus c + + + align:start position:0% +then it's also true for the set x plus c +where x is carefully chosen. I'll + + align:start position:0% +where x is carefully chosen. I'll + + + align:start position:0% +where x is carefully chosen. I'll +explain in a bit how it's chosen but c + + align:start position:0% +explain in a bit how it's chosen but c + + + align:start position:0% +explain in a bit how it's chosen but c +is a totally arbitrary set. So there are + + align:start position:0% +is a totally arbitrary set. So there are + + + align:start position:0% +is a totally arbitrary set. So there are +many choices for C. So there are many + + align:start position:0% +many choices for C. So there are many + + + align:start position:0% +many choices for C. So there are many +different you know this this is many + + align:start position:0% +different you know this this is many + + + align:start position:0% +different you know this this is many +inequalities + + align:start position:0% + + + + align:start position:0% + +right? Okay let me um tell you who X is + + align:start position:0% +right? Okay let me um tell you who X is + + + align:start position:0% +right? Okay let me um tell you who X is +which is an important idea in the proof. + + align:start position:0% +which is an important idea in the proof. + + + align:start position:0% +which is an important idea in the proof. +Um so first of all so x is a subset of a + + align:start position:0% +Um so first of all so x is a subset of a + + + align:start position:0% +Um so first of all so x is a subset of a +that we choose in order to minimize + + align:start position:0% + + + + align:start position:0% + +minimize the ratio x + b / x. + + align:start position:0% + + + + align:start position:0% + +So let me give an example that might + + align:start position:0% +So let me give an example that might + + + align:start position:0% +So let me give an example that might +help to motivate why you would want to + + align:start position:0% +help to motivate why you would want to + + + align:start position:0% +help to motivate why you would want to +look at this x. + + align:start position:0% +look at this x. + + + align:start position:0% +look at this x. +So suppose that a is the numbers from + + align:start position:0% +So suppose that a is the numbers from + + + align:start position:0% +So suppose that a is the numbers from +one up to 100 + + align:start position:0% +one up to 100 + + + align:start position:0% +one up to 100 +which has a lot of additive structure + + align:start position:0% +which has a lot of additive structure + + + align:start position:0% +which has a lot of additive structure +together with some random number. So + + align:start position:0% +together with some random number. So + + + align:start position:0% +together with some random number. So +I've put a million + + align:start position:0% + + + + align:start position:0% + +and b is the numbers from one up to say + + align:start position:0% +and b is the numbers from one up to say + + + align:start position:0% +and b is the numbers from one up to say +50. + + align:start position:0% +50. + + + align:start position:0% +50. +Okay. So if you add A and B together, + + align:start position:0% +Okay. So if you add A and B together, + + + align:start position:0% +Okay. So if you add A and B together, +this stuff plus this stuff is quite + + align:start position:0% +this stuff plus this stuff is quite + + + align:start position:0% +this stuff plus this stuff is quite +small. There's a lot of structure there. + + align:start position:0% +small. There's a lot of structure there. + + + align:start position:0% +small. There's a lot of structure there. +Then there's this stuff plus this stuff + + align:start position:0% +Then there's this stuff plus this stuff + + + align:start position:0% +Then there's this stuff plus this stuff +that doesn't have any particular + + align:start position:0% +that doesn't have any particular + + + align:start position:0% +that doesn't have any particular +structure, but since there's only one + + align:start position:0% +structure, but since there's only one + + + align:start position:0% +structure, but since there's only one +stray element here, that's not so many + + align:start position:0% +stray element here, that's not so many + + + align:start position:0% +stray element here, that's not so many +of those either. So A plus B is pretty + + align:start position:0% +of those either. So A plus B is pretty + + + align:start position:0% +of those either. So A plus B is pretty +small. + + align:start position:0% +small. + + + align:start position:0% +small. +Now, who would X be? + + align:start position:0% + + + + align:start position:0% + +X is the subset of A which is chosen to + + align:start position:0% +X is the subset of A which is chosen to + + + align:start position:0% +X is the subset of A which is chosen to +minimize this ratio. + + align:start position:0% +minimize this ratio. + + + align:start position:0% +minimize this ratio. +and including this guy is not so + + align:start position:0% +and including this guy is not so + + + align:start position:0% +and including this guy is not so +helpful. + + align:start position:0% + + + + align:start position:0% + +Um so x would actually be here just the + + align:start position:0% +Um so x would actually be here just the + + + align:start position:0% +Um so x would actually be here just the +numbers from one up to 100. + + align:start position:0% + + + + align:start position:0% + +Okay. So I think perhaps that + + align:start position:0% +Okay. So I think perhaps that + + + align:start position:0% +Okay. So I think perhaps that +philosophically the point of doing this + + align:start position:0% +philosophically the point of doing this + + + align:start position:0% +philosophically the point of doing this +is identifying the part of A that really + + align:start position:0% +is identifying the part of A that really + + + align:start position:0% +is identifying the part of A that really +has the additive structure and throwing + + align:start position:0% +has the additive structure and throwing + + + align:start position:0% +has the additive structure and throwing +away possibly some parts of A that are + + align:start position:0% +away possibly some parts of A that are + + + align:start position:0% +away possibly some parts of A that are +not not that relevant. + + align:start position:0% +not not that relevant. + + + align:start position:0% +not not that relevant. +Okay. And then once you have found the + + align:start position:0% +Okay. And then once you have found the + + + align:start position:0% +Okay. And then once you have found the +heart of the matter here um then + + align:start position:0% +heart of the matter here um then + + + align:start position:0% +heart of the matter here um then +you can you can add anything else to it + + align:start position:0% +you can you can add anything else to it + + + align:start position:0% +you can you can add anything else to it +and you still have that amount of + + align:start position:0% +and you still have that amount of + + + align:start position:0% +and you still have that amount of +structure. + + align:start position:0% + + + + align:start position:0% + +Okay. + + align:start position:0% + + + + align:start position:0% + +All right. So, let's give a name. Let's + + align:start position:0% +All right. So, let's give a name. Let's + + + align:start position:0% +All right. So, let's give a name. Let's +say that. So, that's who X is. And let's + + align:start position:0% +say that. So, that's who X is. And let's + + + align:start position:0% +say that. So, that's who X is. And let's +say x + b / x is k lower bar which is at + + align:start position:0% +say x + b / x is k lower bar which is at + + + align:start position:0% +say x + b / x is k lower bar which is at +most k. + + align:start position:0% +most k. + + + align:start position:0% +most k. +So a + b over a is at most k and x is + + align:start position:0% +So a + b over a is at most k and x is + + + align:start position:0% +So a + b over a is at most k and x is +allowed to be all of a but we might + + align:start position:0% +allowed to be all of a but we might + + + align:start position:0% +allowed to be all of a but we might +choose a smaller set if we can make this + + align:start position:0% +choose a smaller set if we can make this + + + align:start position:0% +choose a smaller set if we can make this +ratio even smaller. So k bar is less + + align:start position:0% +ratio even smaller. So k bar is less + + + align:start position:0% +ratio even smaller. So k bar is less +than or equal to k. Okay. And really the + + align:start position:0% +than or equal to k. Okay. And really the + + + align:start position:0% +than or equal to k. Okay. And really the +key claim + + align:start position:0% +key claim + + + align:start position:0% +key claim +is that x + c + b over x + c is at most + + align:start position:0% +is that x + c + b over x + c is at most + + + align:start position:0% +is that x + c + b over x + c is at most +k lower barc. + + align:start position:0% + + + + align:start position:0% + +Okay. So now we're going to prove the + + align:start position:0% +Okay. So now we're going to prove the + + + align:start position:0% +Okay. So now we're going to prove the +claim by induction. + + align:start position:0% + + + + align:start position:0% + +So we're going to prove the claim by + + align:start position:0% +So we're going to prove the claim by + + + align:start position:0% +So we're going to prove the claim by +induction + + align:start position:0% +induction + + + align:start position:0% +induction +on the cardality of C. + + align:start position:0% +on the cardality of C. + + + align:start position:0% +on the cardality of C. +And if the cardality of C is 1, then X + + + align:start position:0% +And if the cardality of C is 1, then X + + + + align:start position:0% +And if the cardality of C is 1, then X + +C + B is just X + B + + align:start position:0% +C + B is just X + B + + + align:start position:0% +C + B is just X + B +and X + C is just X. So if the cardality + + align:start position:0% +and X + C is just X. So if the cardality + + + align:start position:0% +and X + C is just X. So if the cardality +of C is one, I'm just shifting this set. + + align:start position:0% +of C is one, I'm just shifting this set. + + + align:start position:0% +of C is one, I'm just shifting this set. +and shifting that set doesn't change + + align:start position:0% +and shifting that set doesn't change + + + align:start position:0% +and shifting that set doesn't change +their cardalities. + + align:start position:0% +their cardalities. + + + align:start position:0% +their cardalities. +Okay. So now we can do the inductive + + align:start position:0% +Okay. So now we can do the inductive + + + align:start position:0% +Okay. So now we can do the inductive +step. + + align:start position:0% + + + + align:start position:0% + +All right. So let's say that C prime is + + align:start position:0% +All right. So let's say that C prime is + + + align:start position:0% +All right. So let's say that C prime is +C union one more guy. And by induction + + align:start position:0% +C union one more guy. And by induction + + + align:start position:0% +C union one more guy. And by induction +we know that it's true for C. So we know + + align:start position:0% +we know that it's true for C. So we know + + + align:start position:0% +we know that it's true for C. So we know +x + c + b is bounded by k lower bar x + + + align:start position:0% +x + c + b is bounded by k lower bar x + + + + align:start position:0% +x + c + b is bounded by k lower bar x + +c and we want to check for crop. + + align:start position:0% + + + + align:start position:0% + +All right. + + align:start position:0% + + + + align:start position:0% + +Okay. So the key character in this + + align:start position:0% +Okay. So the key character in this + + + align:start position:0% +Okay. So the key character in this +argument that Petrus came up with + + align:start position:0% +argument that Petrus came up with + + + align:start position:0% +argument that Petrus came up with +is a set y which is the set of x and x. + + align:start position:0% +is a set y which is the set of x and x. + + + align:start position:0% +is a set y which is the set of x and x. +So that x + little c + b is contained in + + align:start position:0% +So that x + little c + b is contained in + + + align:start position:0% +So that x + little c + b is contained in +big x plus big c plus b. Let's see how + + align:start position:0% +big x plus big c plus b. Let's see how + + + align:start position:0% +big x plus big c plus b. Let's see how +that naturally comes up. + + align:start position:0% + + + + align:start position:0% + +Right. + + align:start position:0% +Right. + + + align:start position:0% +Right. +All right. + + align:start position:0% + + + + align:start position:0% + +So we we we're thinking about x plus c + + align:start position:0% +So we we we're thinking about x plus c + + + align:start position:0% +So we we we're thinking about x plus c +prime plus b. We want to see that it's + + align:start position:0% +prime plus b. We want to see that it's + + + align:start position:0% +prime plus b. We want to see that it's +not too big. And we're using induction. + + align:start position:0% +not too big. And we're using induction. + + + align:start position:0% +not too big. And we're using induction. +So we want to see how it changes when we + + align:start position:0% +So we want to see how it changes when we + + + align:start position:0% +So we want to see how it changes when we +added this one guy. So this is the + + align:start position:0% +added this one guy. So this is the + + + align:start position:0% +added this one guy. So this is the +previous guy x + c + b plus um + + align:start position:0% +previous guy x + c + b plus um + + + align:start position:0% +previous guy x + c + b plus um +the new ones. + + align:start position:0% +the new ones. + + + align:start position:0% +the new ones. +And I want them to be really new. + + align:start position:0% + + + + align:start position:0% + +So, here are some new elements that live + + align:start position:0% +So, here are some new elements that live + + + align:start position:0% +So, here are some new elements that live +here. And I'm going to take out any + + align:start position:0% +here. And I'm going to take out any + + + align:start position:0% +here. And I'm going to take out any +elements I've already counted, + + align:start position:0% + + + + align:start position:0% + +right? + + align:start position:0% + + + + align:start position:0% + +Sorry. Um, + + align:start position:0% +Sorry. Um, + + + align:start position:0% +Sorry. Um, +how, um, I don't quite understand the + + align:start position:0% +how, um, I don't quite understand the + + + align:start position:0% +how, um, I don't quite understand the +definition of y. How can x plus c plus b + + align:start position:0% +definition of y. How can x plus c plus b + + + align:start position:0% +definition of y. How can x plus c plus b +not be a subset of x plus c plus b? + + align:start position:0% +not be a subset of x plus c plus b? + + + align:start position:0% +not be a subset of x plus c plus b? +>> Right? So this uh so c prime is a + + align:start position:0% +>> Right? So this uh so c prime is a + + + align:start position:0% +>> Right? So this uh so c prime is a +previous set c union with some little c + + align:start position:0% +previous set c union with some little c + + + align:start position:0% +previous set c union with some little c +>> and little c is not in big c. + + align:start position:0% +>> and little c is not in big c. + + + align:start position:0% +>> and little c is not in big c. +>> Okay. Now I have to write all the little + + align:start position:0% +>> Okay. Now I have to write all the little + + + align:start position:0% +>> Okay. Now I have to write all the little +c's and big c's really carefully. But + + align:start position:0% +c's and big c's really carefully. But + + + align:start position:0% +c's and big c's really carefully. But +this is a little c and this is a big c. + + align:start position:0% +this is a little c and this is a big c. + + + align:start position:0% +this is a little c and this is a big c. +Cool. Okay. So this X is automatically + + align:start position:0% +Cool. Okay. So this X is automatically + + + align:start position:0% +Cool. Okay. So this X is automatically +in big X but in a failure of + + align:start position:0% +in big X but in a failure of + + + align:start position:0% +in big X but in a failure of +functorality of not of notation little C + + align:start position:0% +functorality of not of notation little C + + + align:start position:0% +functorality of not of notation little C +is not in big C. + + align:start position:0% + + + + align:start position:0% + +All right. + + align:start position:0% +All right. + + + align:start position:0% +All right. +All right. + + align:start position:0% + + + + align:start position:0% + +Okay. Now, one thing to note about this + + align:start position:0% +Okay. Now, one thing to note about this + + + align:start position:0% +Okay. Now, one thing to note about this +definition that helps to motivate it is + + align:start position:0% +definition that helps to motivate it is + + + align:start position:0% +definition that helps to motivate it is +that y + little c plus big b is + + align:start position:0% +that y + little c plus big b is + + + align:start position:0% +that y + little c plus big b is +contained in x plus big c plus big b + + align:start position:0% + + + + align:start position:0% + +because for each element of y, little y + + align:start position:0% +because for each element of y, little y + + + align:start position:0% +because for each element of y, little y +plus little c plus big b is defined to + + align:start position:0% +plus little c plus big b is defined to + + + align:start position:0% +plus little c plus big b is defined to +be in here. + + align:start position:0% + + + + align:start position:0% + +So this is at most x + c + b plus + + align:start position:0% +So this is at most x + c + b plus + + + align:start position:0% +So this is at most x + c + b plus +x + c + b take away y + c + b. + + align:start position:0% + + + + align:start position:0% + +All of these were already counted. So + + align:start position:0% +All of these were already counted. So + + + align:start position:0% +All of these were already counted. So +there are at most this many new guys. + + align:start position:0% +there are at most this many new guys. + + + align:start position:0% +there are at most this many new guys. +All right. And this is x + c + b + x + b + + align:start position:0% +All right. And this is x + c + b + x + b + + + align:start position:0% +All right. And this is x + c + b + x + b +- y + b because this is a subset of this + + align:start position:0% +- y + b because this is a subset of this + + + align:start position:0% +- y + b because this is a subset of this +and the plus c just translates things. + + align:start position:0% +and the plus c just translates things. + + + align:start position:0% +and the plus c just translates things. +So I have so this thing is that big and + + align:start position:0% +So I have so this thing is that big and + + + align:start position:0% +So I have so this thing is that big and +I remove from it this thing which is + + align:start position:0% +I remove from it this thing which is + + + align:start position:0% +I remove from it this thing which is +that big. + + align:start position:0% +that big. + + + align:start position:0% +that big. +So that's the upper bound for um the + + align:start position:0% +So that's the upper bound for um the + + + align:start position:0% +So that's the upper bound for um the +numerator. + + align:start position:0% + + + + align:start position:0% + +Okay. + + align:start position:0% +Okay. + + + align:start position:0% +Okay. +Um, + + align:start position:0% +Um, + + + align:start position:0% +Um, +so I'm I'm trying to bound this thing + + align:start position:0% +so I'm I'm trying to bound this thing + + + align:start position:0% +so I'm I'm trying to bound this thing +with a C prime. I need I want to prove + + align:start position:0% +with a C prime. I need I want to prove + + + align:start position:0% +with a C prime. I need I want to prove +an upper bound. So I need an upper bound + + align:start position:0% +an upper bound. So I need an upper bound + + + align:start position:0% +an upper bound. So I need an upper bound +for the numerator and a lower bound for + + align:start position:0% +for the numerator and a lower bound for + + + align:start position:0% +for the numerator and a lower bound for +the denominator. + + align:start position:0% + + + + align:start position:0% + +Okay, + + align:start position:0% + + + + align:start position:0% + +so the denominator is x + + + align:start position:0% +so the denominator is x + + + + align:start position:0% +so the denominator is x + +uh c prime + + align:start position:0% +uh c prime + + + align:start position:0% +uh c prime +and so that's x + c plus um the the set + + align:start position:0% +and so that's x + c plus um the the set + + + align:start position:0% +and so that's x + c plus um the the set +how many x and x. So that little x plus + + align:start position:0% +how many x and x. So that little x plus + + + align:start position:0% +how many x and x. So that little x plus +little c is not contained in big x plus + + align:start position:0% +little c is not contained in big x plus + + + align:start position:0% +little c is not contained in big x plus +big c. + + align:start position:0% +big c. + + + align:start position:0% +big c. +So it's the guys I already had and then + + align:start position:0% +So it's the guys I already had and then + + + align:start position:0% +So it's the guys I already had and then +I have guys of the format little x plus + + align:start position:0% +I have guys of the format little x plus + + + align:start position:0% +I have guys of the format little x plus +little c. And I only want the new ones, + + align:start position:0% +little c. And I only want the new ones, + + + align:start position:0% +little c. And I only want the new ones, +the ones that aren't already counted. + + align:start position:0% +the ones that aren't already counted. + + + align:start position:0% +the ones that aren't already counted. +That's an equality. And I'm gonna write + + align:start position:0% +That's an equality. And I'm gonna write + + + align:start position:0% +That's an equality. And I'm gonna write +it as x + c plus x minus the x and x. So + + align:start position:0% +it as x + c plus x minus the x and x. So + + + align:start position:0% +it as x + c plus x minus the x and x. So +that x + c is an x plus c. + + align:start position:0% + + + + align:start position:0% + +Okay. And now key observation is that + + align:start position:0% +Okay. And now key observation is that + + + align:start position:0% +Okay. And now key observation is that +these guys are all in y. + + align:start position:0% + + + + align:start position:0% + +This is a subset of y. + + align:start position:0% +This is a subset of y. + + + align:start position:0% +This is a subset of y. +Right? Because if little x plus little c + + align:start position:0% +Right? Because if little x plus little c + + + align:start position:0% +Right? Because if little x plus little c +is in big x plus big c. Um so if little + + align:start position:0% +is in big x plus big c. Um so if little + + + align:start position:0% +is in big x plus big c. Um so if little +x plus little c is in big x plus big c + + align:start position:0% +x plus little c is in big x plus big c + + + align:start position:0% +x plus little c is in big x plus big c +then I can add b to both sides and this + + align:start position:0% +then I can add b to both sides and this + + + align:start position:0% +then I can add b to both sides and this +is in there. + + align:start position:0% +is in there. + + + align:start position:0% +is in there. +So those are all in y. + + align:start position:0% + + + + align:start position:0% + +So this is a subset of y. So the size of + + align:start position:0% +So this is a subset of y. So the size of + + + align:start position:0% +So this is a subset of y. So the size of +this guy is at most the size of y. And + + align:start position:0% +this guy is at most the size of y. And + + + align:start position:0% +this guy is at most the size of y. And +since I'm subtracting here, I can say + + align:start position:0% +since I'm subtracting here, I can say + + + align:start position:0% +since I'm subtracting here, I can say +this is at least x + c + x minus y. + + align:start position:0% + + + + align:start position:0% + +Okay. + + align:start position:0% +Okay. + + + align:start position:0% +Okay. +So now we'll just put together + + align:start position:0% +So now we'll just put together + + + align:start position:0% +So now we'll just put together +everything that we know. + + align:start position:0% + + + + align:start position:0% + +Okay. We know that x + c + b over x + c + + align:start position:0% +Okay. We know that x + c + b over x + c + + + align:start position:0% +Okay. We know that x + c + b over x + c +is at most k bar. We know that by + + align:start position:0% +is at most k bar. We know that by + + + align:start position:0% +is at most k bar. We know that by +induction. + + align:start position:0% + + + + align:start position:0% + +We know that x + b / x is equal to k + + align:start position:0% +We know that x + b / x is equal to k + + + align:start position:0% +We know that x + b / x is equal to k +bar. We know that by definition. That's + + align:start position:0% +bar. We know that by definition. That's + + + align:start position:0% +bar. We know that by definition. That's +just what k bar was. + + align:start position:0% + + + + align:start position:0% + +And we know that y + b over y is greater + + align:start position:0% +And we know that y + b over y is greater + + + align:start position:0% +And we know that y + b over y is greater +than or equal to k bar. That was the + + align:start position:0% +than or equal to k bar. That was the + + + align:start position:0% +than or equal to k bar. That was the +definition of x. x was chosen to + + align:start position:0% +definition of x. x was chosen to + + + align:start position:0% +definition of x. x was chosen to +minimize this ratio. + + align:start position:0% +minimize this ratio. + + + align:start position:0% +minimize this ratio. +Y might perhaps be equal to x, but + + align:start position:0% +Y might perhaps be equal to x, but + + + align:start position:0% +Y might perhaps be equal to x, but +that's that's okay anyway. But it's + + align:start position:0% +that's that's okay anyway. But it's + + + align:start position:0% +that's that's okay anyway. But it's +never going to be any smaller. + + align:start position:0% + + + + align:start position:0% + +Okay? And so therefore by algebra by how + + align:start position:0% +Okay? And so therefore by algebra by how + + + align:start position:0% +Okay? And so therefore by algebra by how +fractions work x + c + b. Okay. So so + + align:start position:0% +fractions work x + c + b. Okay. So so + + + align:start position:0% +fractions work x + c + b. Okay. So so +now I can say I I want to say x + c + + align:start position:0% +now I can say I I want to say x + c + + + align:start position:0% +now I can say I I want to say x + c +prime + b over x + c prime. And I want + + align:start position:0% +prime + b over x + c prime. And I want + + + align:start position:0% +prime + b over x + c prime. And I want +an upper bound for that. + + align:start position:0% +an upper bound for that. + + + align:start position:0% +an upper bound for that. +Okay. So the numerator is bounded by 1. + + align:start position:0% +Okay. So the numerator is bounded by 1. + + + align:start position:0% +Okay. So the numerator is bounded by 1. +x + c + b + x + b + + align:start position:0% +x + c + b + x + b + + + align:start position:0% +x + c + b + x + b +minus y + b. + + align:start position:0% +minus y + b. + + + align:start position:0% +minus y + b. +And the denominator is lower bounded by + + align:start position:0% +And the denominator is lower bounded by + + + align:start position:0% +And the denominator is lower bounded by +part two and it's x + c + x - y. + + align:start position:0% + + + + align:start position:0% + +And then because each of these ratios + + align:start position:0% +And then because each of these ratios + + + align:start position:0% +And then because each of these ratios +has the correct sign, this is at most k. + + align:start position:0% + + + + align:start position:0% + +Yeah. So this is short. It is a little + + align:start position:0% +Yeah. So this is short. It is a little + + + align:start position:0% +Yeah. So this is short. It is a little +tricky and I must admit I don't quite + + align:start position:0% +tricky and I must admit I don't quite + + + align:start position:0% +tricky and I must admit I don't quite +understand how Petrus thought to do + + align:start position:0% +understand how Petrus thought to do + + + align:start position:0% +understand how Petrus thought to do +this. + + align:start position:0% + + + + align:start position:0% + +Um + + align:start position:0% + + + + align:start position:0% + +Okay. So from the key lama we can prove + + align:start position:0% +Okay. So from the key lama we can prove + + + align:start position:0% +Okay. So from the key lama we can prove +uh plunic's inequality + + align:start position:0% +uh plunic's inequality + + + align:start position:0% +uh plunic's inequality +and then see if anybody + + align:start position:0% +and then see if anybody + + + align:start position:0% +and then see if anybody +yeah if you have room you can turn turn + + align:start position:0% +yeah if you have room you can turn turn + + + align:start position:0% +yeah if you have room you can turn turn +over in your mind + + align:start position:0% +over in your mind + + + align:start position:0% +over in your mind +why did philosophically why did this + + align:start position:0% +why did philosophically why did this + + + align:start position:0% +why did philosophically why did this +work out so nicely. If anybody has + + align:start position:0% +work out so nicely. If anybody has + + + align:start position:0% +work out so nicely. If anybody has +thoughts about it I would be happy to + + align:start position:0% +thoughts about it I would be happy to + + + align:start position:0% +thoughts about it I would be happy to +hear. + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% + + + + align:start position:0% + +Okay. So, proof. Okay. So, say we're + + align:start position:0% +Okay. So, proof. Okay. So, say we're + + + align:start position:0% +Okay. So, proof. Okay. So, say we're +starting with this. + + align:start position:0% +starting with this. + + + align:start position:0% +starting with this. +Um + + align:start position:0% + + + + align:start position:0% + +so by the main the main we use our main + + align:start position:0% +so by the main the main we use our main + + + align:start position:0% +so by the main the main we use our main +lema. + + align:start position:0% +lema. + + + align:start position:0% +lema. +So it tells us that there exists some x + + align:start position:0% +So it tells us that there exists some x + + + align:start position:0% +So it tells us that there exists some x +and a and we have x + c + b at most k * + + align:start position:0% +and a and we have x + c + b at most k * + + + align:start position:0% +and a and we have x + c + b at most k * +x + c for any c. + + align:start position:0% +x + c for any c. + + + align:start position:0% +x + c for any c. +How might we use this? + + align:start position:0% +How might we use this? + + + align:start position:0% +How might we use this? +Um + + align:start position:0% + + + + align:start position:0% + +right. So okay, C could be empty. So we + + align:start position:0% +right. So okay, C could be empty. So we + + + align:start position:0% +right. So okay, C could be empty. So we +get X + B is at most K * X. + + align:start position:0% +get X + B is at most K * X. + + + align:start position:0% +get X + B is at most K * X. +C could be B. So we get X + B + B. + + align:start position:0% +C could be B. So we get X + B + B. + + + align:start position:0% +C could be B. So we get X + B + B. +That's at most K * X + B. + + align:start position:0% +That's at most K * X + B. + + + align:start position:0% +That's at most K * X + B. +And X plus B was at most K * X. So + + align:start position:0% +And X plus B was at most K * X. So + + + align:start position:0% +And X plus B was at most K * X. So +that's at most K 2 * X. + + align:start position:0% + + + + align:start position:0% + +Okay. And you can see where this goes. + + align:start position:0% +Okay. And you can see where this goes. + + + align:start position:0% +Okay. And you can see where this goes. +So I'll do one more. you'll get the + + align:start position:0% +So I'll do one more. you'll get the + + + align:start position:0% +So I'll do one more. you'll get the +pattern. If I add one more b, that's at + + align:start position:0% +pattern. If I add one more b, that's at + + + align:start position:0% +pattern. If I add one more b, that's at +most k x plus b plus b. Plug in what I + + align:start position:0% +most k x plus b plus b. Plug in what I + + + align:start position:0% +most k x plus b plus b. Plug in what I +already know about this. That's at most + + align:start position:0% +already know about this. That's at most + + + align:start position:0% +already know about this. That's at most +k cub * x. All right. So if I add x + m + + align:start position:0% +k cub * x. All right. So if I add x + m + + + align:start position:0% +k cub * x. All right. So if I add x + m +copies of b, that will be at most k * x. + + align:start position:0% + + + + align:start position:0% + +Okay. + + align:start position:0% +Okay. + + + align:start position:0% +Okay. +And then uh + + align:start position:0% +And then uh + + + align:start position:0% +And then uh +we'll use the roua inequality. So this + + align:start position:0% +we'll use the roua inequality. So this + + + align:start position:0% +we'll use the roua inequality. So this +is already you know if um + + align:start position:0% +is already you know if um + + + align:start position:0% +is already you know if um +uh this is already pretty good thing uh + + align:start position:0% +uh this is already pretty good thing uh + + + align:start position:0% +uh this is already pretty good thing uh +like if a equals b here then I could say + + align:start position:0% +like if a equals b here then I could say + + + align:start position:0% +like if a equals b here then I could say +a to the m is bounded by k to the m * a + + align:start position:0% +a to the m is bounded by k to the m * a + + + align:start position:0% +a to the m is bounded by k to the m * a +right because a to the a to the m is + + align:start position:0% +right because a to the a to the m is + + + align:start position:0% +right because a to the a to the m is +obviously at least as big as x plus a to + + align:start position:0% +obviously at least as big as x plus a to + + + align:start position:0% +obviously at least as big as x plus a to +the m. So I get a the m is bounded by k + + align:start position:0% +the m. So I get a the m is bounded by k + + + align:start position:0% +the m. So I get a the m is bounded by k +the m * a. That's a typical correlary of + + align:start position:0% +the m * a. That's a typical correlary of + + + align:start position:0% +the m * a. That's a typical correlary of +Pluner. + + align:start position:0% +Pluner. + + + align:start position:0% +Pluner. +Anyway, to get the uh advertised finale, + + align:start position:0% +Anyway, to get the uh advertised finale, + + + align:start position:0% +Anyway, to get the uh advertised finale, +we use Ruse's inequality. + + align:start position:0% +we use Ruse's inequality. + + + align:start position:0% +we use Ruse's inequality. +Ruser was a times + + align:start position:0% + + + + align:start position:0% + +there. + + align:start position:0% +there. + + + align:start position:0% +there. +So can plug in um + + align:start position:0% +So can plug in um + + + align:start position:0% +So can plug in um +uh + + align:start position:0% +uh + + + align:start position:0% +uh +I say so x * b + m - b + n is bounded by + + align:start position:0% +I say so x * b + m - b + n is bounded by + + + align:start position:0% +I say so x * b + m - b + n is bounded by +x + b + m + + align:start position:0% +x + b + m + + + align:start position:0% +x + b + m +x + b + n. + + align:start position:0% + + + + align:start position:0% + +Uh + + align:start position:0% +Uh + + + align:start position:0% +Uh +and then we plug in each of these and we + + align:start position:0% +and then we plug in each of these and we + + + align:start position:0% +and then we plug in each of these and we +get k to the m + n + + align:start position:0% +get k to the m + n + + + align:start position:0% +get k to the m + n +* x* + + align:start position:0% +* x* + + + align:start position:0% +* x* +x². + + align:start position:0% + + + + align:start position:0% + +Yeah, that's right. Okay. So then I uh + + align:start position:0% +Yeah, that's right. Okay. So then I uh + + + align:start position:0% +Yeah, that's right. Okay. So then I uh +get this by itself. So b + m - b + n is + + align:start position:0% +get this by itself. So b + m - b + n is + + + align:start position:0% +get this by itself. So b + m - b + n is +bounded by k m + n * x which is bounded + + align:start position:0% +bounded by k m + n * x which is bounded + + + align:start position:0% +bounded by k m + n * x which is bounded +by k the m + n * a because x is a subset + + align:start position:0% +by k the m + n * a because x is a subset + + + align:start position:0% +by k the m + n * a because x is a subset +of a + + align:start position:0% + + + + align:start position:0% + +Okay, so this proof is short. It is a + + align:start position:0% +Okay, so this proof is short. It is a + + + align:start position:0% +Okay, so this proof is short. It is a +little tricky, but I think it is well + + align:start position:0% +little tricky, but I think it is well + + + align:start position:0% +little tricky, but I think it is well +worth spending some time with uh because + + align:start position:0% +worth spending some time with uh because + + + align:start position:0% +worth spending some time with uh because +this inequality is really quite + + align:start position:0% +this inequality is really quite + + + align:start position:0% +this inequality is really quite +important. I would say that it plays + + align:start position:0% +important. I would say that it plays + + + align:start position:0% +important. I would say that it plays +really a key role in all the later + + align:start position:0% +really a key role in all the later + + + align:start position:0% +really a key role in all the later +developments in projection theory and + + align:start position:0% +developments in projection theory and + + + align:start position:0% +developments in projection theory and +the solution to the CA problem in a lot + + align:start position:0% +the solution to the CA problem in a lot + + + align:start position:0% +the solution to the CA problem in a lot +of things. + + align:start position:0% +of things. + + + align:start position:0% +of things. +Um and uh so as we keep going, you know, + + align:start position:0% +Um and uh so as we keep going, you know, + + + align:start position:0% +Um and uh so as we keep going, you know, +tomorrow, Thursday, and so on, we'll + + align:start position:0% +tomorrow, Thursday, and so on, we'll + + + align:start position:0% +tomorrow, Thursday, and so on, we'll +reflect more about why this is useful + + align:start position:0% +reflect more about why this is useful + + + align:start position:0% +reflect more about why this is useful +and important. Um and um maybe I'll try + + align:start position:0% +and important. Um and um maybe I'll try + + + align:start position:0% +and important. Um and um maybe I'll try +to come up with some homework to try to + + align:start position:0% +to come up with some homework to try to + + + align:start position:0% +to come up with some homework to try to +reflect on on uh how this proof got put + + align:start position:0% +reflect on on uh how this proof got put + + + align:start position:0% +reflect on on uh how this proof got put +together. \ No newline at end of file diff --git a/VRMakiEeVJM.txt b/VRMakiEeVJM.txt new file mode 100644 index 0000000000000000000000000000000000000000..a7fe1c54aa41b78172d4b25e720d20a95fb691ec --- /dev/null +++ b/VRMakiEeVJM.txt @@ -0,0 +1,10028 @@ +align:start position:0% + +so we talked about Rhythm last time all + + align:start position:0% +so we talked about Rhythm last time all + + + align:start position:0% +so we talked about Rhythm last time all +right so the most important thing that + + align:start position:0% +right so the most important thing that + + + align:start position:0% +right so the most important thing that +you want to remember + + align:start position:0% +you want to remember + + + align:start position:0% +you want to remember +is what stressing the content words or + + align:start position:0% +is what stressing the content words or + + + align:start position:0% +is what stressing the content words or +function words content words you stress + + align:start position:0% +function words content words you stress + + + align:start position:0% +function words content words you stress +the content words right you stress the + + align:start position:0% +the content words right you stress the + + + align:start position:0% +the content words right you stress the +content words + + align:start position:0% +content words + + + align:start position:0% +content words +now what happens + + align:start position:0% +now what happens + + + align:start position:0% +now what happens +to what happens to the function words + + align:start position:0% + + + + align:start position:0% + +then the vowels + + align:start position:0% +then the vowels + + + align:start position:0% +then the vowels +per yes you do not stress function Words + + align:start position:0% +per yes you do not stress function Words + + + align:start position:0% +per yes you do not stress function Words +which means function words vowels in + + align:start position:0% +which means function words vowels in + + + align:start position:0% +which means function words vowels in +those function words gets reduced get + + align:start position:0% +those function words gets reduced get + + + align:start position:0% +those function words gets reduced get +reduced when we say two words really + + align:start position:0% +reduced when we say two words really + + + align:start position:0% +reduced when we say two words really +fast it + + align:start position:0% + + + + align:start position:0% + +becomes D becomes a flap right the all + + align:start position:0% +becomes D becomes a flap right the all + + + align:start position:0% +becomes D becomes a flap right the all +these in + + align:start position:0% + + + + align:start position:0% + +should all the these in all those three + + align:start position:0% +should all the these in all those three + + + align:start position:0% +should all the these in all those three +words become a flap right sh what so + + align:start position:0% +words become a flap right sh what so + + + align:start position:0% +words become a flap right sh what so +what's actually sh + + align:start position:0% +what's actually sh + + + align:start position:0% +what's actually sh +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +should is + + align:start position:0% +should is + + + align:start position:0% +should is +actually should have + + align:start position:0% +actually should have + + + align:start position:0% +actually should have +right should have right you get rid of + + align:start position:0% +right should have right you get rid of + + + align:start position:0% +right should have right you get rid of +the H you get rid of V okay when it's + + align:start position:0% +the H you get rid of V okay when it's + + + align:start position:0% +the H you get rid of V okay when it's +usually followed by a consonant you get + + align:start position:0% +usually followed by a consonant you get + + + align:start position:0% +usually followed by a consonant you get +rid of the + + align:start position:0% +rid of the + + + align:start position:0% +rid of the +V you look it up in the dictionary it's + + align:start position:0% +V you look it up in the dictionary it's + + + align:start position:0% +V you look it up in the dictionary it's +have right you get rid of V you get rid + + align:start position:0% +have right you get rid of V you get rid + + + align:start position:0% +have right you get rid of V you get rid +of H now a gets reduced to a + + align:start position:0% +of H now a gets reduced to a + + + align:start position:0% +of H now a gets reduced to a +right so we + + align:start position:0% +right so we + + + align:start position:0% +right so we +have should should right now we're going + + align:start position:0% +have should should right now we're going + + + align:start position:0% +have should should right now we're going +to link it + + align:start position:0% + + + + align:start position:0% + +together right d comes between two vows + + align:start position:0% +together right d comes between two vows + + + align:start position:0% +together right d comes between two vows +right so they become + + align:start position:0% +right so they become + + + align:start position:0% +right so they become +sh sh right this is what we actually + + align:start position:0% +sh sh right this is what we actually + + + align:start position:0% +sh sh right this is what we actually +say + + align:start position:0% + + + + align:start position:0% + +sh okay sh should + + align:start position:0% + + + + align:start position:0% + +have so does that make sense there are + + align:start position:0% +have so does that make sense there are + + + align:start position:0% +have so does that make sense there are +people who should have could it what and + + align:start position:0% +people who should have could it what and + + + align:start position:0% +people who should have could it what and +there are people who are glad they + + align:start position:0% + + + + align:start position:0% + +did okay should have could have would + + align:start position:0% +did okay should have could have would + + + align:start position:0% +did okay should have could have would +should have I should have gone I could + + align:start position:0% +should have I should have gone I could + + + align:start position:0% +should have I should have gone I could +have gone if I had more + + align:start position:0% + + + + align:start position:0% + +money I could have gone had I had more + + align:start position:0% +money I could have gone had I had more + + + align:start position:0% +money I could have gone had I had more +money I would have gone had I had more + + align:start position:0% +money I would have gone had I had more + + + align:start position:0% +money I would have gone had I had more +time and there are people who are glad + + align:start position:0% +time and there are people who are glad + + + align:start position:0% +time and there are people who are glad +they you did so + + align:start position:0% + + + + align:start position:0% + +okay now let's go back to + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +our oh very + + align:start position:0% + + + + align:start position:0% + +interesting oh + + align:start position:0% + + + + align:start position:0% + +go back to our course + + align:start position:0% + + + + align:start position:0% + +packet I you to do this + + align:start position:0% + + + + align:start position:0% + +right find the right mattress find the + + align:start position:0% +right find the right mattress find the + + + align:start position:0% +right find the right mattress find the +right + + align:start position:0% +right + + + align:start position:0% +right +mattress okay compare your answers with + + align:start position:0% +mattress okay compare your answers with + + + align:start position:0% +mattress okay compare your answers with +your NE compare your + + align:start position:0% + + + + align:start position:0% + +answers page 71 page 71 in your course + + align:start position:0% + + + + align:start position:0% + +packet homework + + align:start position:0% +packet homework + + + align:start position:0% +packet homework +home home not class fork okay compare + + align:start position:0% +home home not class fork okay compare + + + align:start position:0% +home home not class fork okay compare +your + + align:start position:0% + + + + align:start position:0% + +answers hmark people hmark you can + + align:start position:0% +answers hmark people hmark you can + + + align:start position:0% +answers hmark people hmark you can +compare your answers + + align:start position:0% +compare your answers + + + align:start position:0% +compare your answers +with okay yeah compare your answers Jen + + align:start position:0% +with okay yeah compare your answers Jen + + + align:start position:0% +with okay yeah compare your answers Jen +and youan + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +number + + align:start position:0% +number + + + align:start position:0% +number +one everyone number one here up here up + + align:start position:0% +one everyone number one here up here up + + + align:start position:0% +one everyone number one here up here up +here up here number + + align:start position:0% +here up here number + + + align:start position:0% +here up here number +one okay say this say number one all of + + align:start position:0% +one okay say this say number one all of + + + align:start position:0% +one okay say this say number one all of +us all of you + + align:start position:0% +us all of you + + + align:start position:0% +us all of you +guys one more time try try to sleep or + + align:start position:0% +guys one more time try try to sleep or + + + align:start position:0% +guys one more time try try to sleep or +let's have the flap try to sleep try to + + align:start position:0% +let's have the flap try to sleep try to + + + align:start position:0% +let's have the flap try to sleep try to +sleep try to sleep try to sleep how many + + align:start position:0% +sleep try to sleep try to sleep how many + + + align:start position:0% +sleep try to sleep try to sleep how many +syllables + + align:start position:0% +syllables + + + align:start position:0% +syllables +three three syllables right three + + align:start position:0% +three three syllables right three + + + align:start position:0% +three three syllables right three +syllables what's okay what's the stress + + align:start position:0% +syllables what's okay what's the stress + + + align:start position:0% +syllables what's okay what's the stress +stress pattern what's the rhythmic + + align:start position:0% + + + + align:start position:0% + +pattern content content so the answer is + + align:start position:0% +pattern content content so the answer is + + + align:start position:0% +pattern content content so the answer is +e okay number two number two + + align:start position:0% +e okay number two number two + + + align:start position:0% +e okay number two number two +volunteer two okay your promise to fall + + align:start position:0% +volunteer two okay your promise to fall + + + align:start position:0% +volunteer two okay your promise to fall +one more time your promise to fall very + + align:start position:0% 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+any questions about + + + align:start position:0% +any questions about +this reducing the vowels very important + + align:start position:0% +this reducing the vowels very important + + + align:start position:0% +this reducing the vowels very important +reducing the vows very important + + align:start position:0% +reducing the vows very important + + + align:start position:0% +reducing the vows very important +okay + + align:start position:0% + + + + align:start position:0% + +now + + align:start position:0% +now + + + align:start position:0% +now +uh how am I gonna one two one two + + align:start position:0% +uh how am I gonna one two one two + + + align:start position:0% +uh how am I gonna one two one two +we're going to okay one two one we're + + align:start position:0% +we're going to okay one two one we're + + + align:start position:0% +we're going to okay one two one we're +going to number off one two one two one + + align:start position:0% +going to number off one two one two one + + + align:start position:0% +going to number off one two one two one +two one two okay one two + + align:start position:0% + + + + align:start position:0% + +one okay one so you're Partners one two + + align:start position:0% +one okay one so you're Partners one two + + + align:start position:0% +one okay one so you're Partners one two +one two you guys are Partners okay and I + + align:start position:0% +one two you guys are Partners okay and I + + + align:start position:0% +one two you guys are Partners okay and I +want you to pick + + align:start position:0% + + + + align:start position:0% + +one is this the right envelope yes okay + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +so each pair gets one sentence each pair + + align:start position:0% +so each pair gets one sentence each pair + + + align:start position:0% +so each pair gets one sentence each pair +gets one + + align:start position:0% +gets one + + + align:start position:0% +gets one +sentence no no no you got you guys got + + align:start position:0% +sentence no no no you got you guys got + + + align:start position:0% +sentence no no no you got you guys got +one + + align:start position:0% +one + + + align:start position:0% +one +already + + align:start position:0% + + + + align:start position:0% + +okay each pair gets one + + align:start position:0% + + + + align:start position:0% + +sentence each pair gets one + + align:start position:0% + + + + align:start position:0% + +sentence okay + + align:start position:0% + + + + align:start position:0% + +okay as a pair your task is + + align:start position:0% + + + + align:start position:0% + +to come up with the correct rhythmic + + align:start position:0% +to come up with the correct rhythmic + + + align:start position:0% +to come up with the correct rhythmic +pattern okay + + align:start position:0% +pattern okay + + + align:start position:0% +pattern okay +like and I'm going to + + align:start position:0% +like and I'm going to + + + align:start position:0% +like and I'm going to +write the patterns on the board + + align:start position:0% + + + + align:start position:0% + +okay so it's the same task first thing + + align:start position:0% +okay so it's the same task first thing + + + align:start position:0% +okay so it's the same task first thing +you need to do is to figure out how many + + align:start position:0% +you need to do is to figure out how many + + + align:start position:0% +you need to do is to figure out how many +syllables your sentence has okay how + + align:start position:0% +syllables your sentence has okay how + + + align:start position:0% +syllables your sentence has okay how +many syllables count that and think + + align:start position:0% +many syllables count that and think + + + align:start position:0% +many syllables count that and think +about okay which ones are content Words + + align:start position:0% +about okay which ones are content Words + + + align:start position:0% +about okay which ones are content Words +which ones are function words and you're + + align:start position:0% +which ones are function words and you're + + + align:start position:0% +which ones are function words and you're +going to have stress on the content + + align:start position:0% +going to have stress on the content + + + align:start position:0% +going to have stress on the content +words right right and then you have to + + align:start position:0% +words right right and then you have to + + + align:start position:0% +words right right and then you have to +reduce function fun words reduce + + align:start position:0% +reduce function fun words reduce + + + align:start position:0% +reduce function fun words reduce +function words and do all the linking + + align:start position:0% +function words and do all the linking + + + align:start position:0% +function words and do all the linking +okay do all the + + align:start position:0% +okay do all the + + + align:start position:0% +okay do all the +linking and as a pair practice saying + + align:start position:0% +linking and as a pair practice saying + + + align:start position:0% +linking and as a pair practice saying +the + + align:start position:0% +the + + + align:start position:0% +the +sentence + + align:start position:0% +sentence + + + align:start position:0% +sentence +as + + align:start position:0% +as + + + align:start position:0% +as +as as correctly as possible together + + align:start position:0% +as as correctly as possible together + + + align:start position:0% +as as correctly as possible together +okay and I'm going to ask uh both of you + + align:start position:0% +okay and I'm going to ask uh both of you + + + align:start position:0% +okay and I'm going to ask uh both of you +to say the sentence together at the same + + align:start position:0% +to say the sentence together at the same + + + align:start position:0% +to say the sentence together at the same +time + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% + + + + align:start position:0% + +we + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% + + + + align:start position:0% + +I think there + + align:start position:0% + + + + align:start position:0% + +yeah probably + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +okay your sentence should have at least + + align:start position:0% +okay your sentence should have at least + + + align:start position:0% +okay your sentence should have at least +should have one of these four patterns + + align:start position:0% +should have one of these four patterns + + + align:start position:0% +should have one of these four patterns +this is the + + align:start position:0% +this is the + + + align:start position:0% +this is the +what this is a reduced uh reduced + + align:start position:0% +what this is a reduced uh reduced + + + align:start position:0% +what this is a reduced uh reduced +syllable this is the stressed syllable + + align:start position:0% +syllable this is the stressed syllable + + + align:start position:0% +syllable this is the stressed syllable +okay and figure that out too + + align:start position:0% + + + + align:start position:0% + +ready ready okay now everyone stand up + + align:start position:0% +ready ready okay now everyone stand up + + + align:start position:0% +ready ready okay now everyone stand up +up up and go to the board stand under + + align:start position:0% +up up and go to the board stand under + + + align:start position:0% +up up and go to the board stand under +your + + align:start position:0% + + + + align:start position:0% + +number SC + + align:start position:0% + + + + align:start position:0% + +okay yeah I I I forgot something I I + + align:start position:0% +okay yeah I I I forgot something I I + + + align:start position:0% +okay yeah I I I forgot something I I +forgot the + + align:start position:0% + + + + align:start position:0% + +lines everyone ready did you did you + + align:start position:0% +lines everyone ready did you did you + + + align:start position:0% +lines everyone ready did you did you +practice see this sentence together okay + + align:start position:0% +practice see this sentence together okay + + + align:start position:0% +practice see this sentence together okay +remember the Rhythm linking get rid of + + align:start position:0% +remember the Rhythm linking get rid of + + + align:start position:0% +remember the Rhythm linking get rid of +certain sounds okay reduce the + + align:start position:0% +certain sounds okay reduce the + + + align:start position:0% +certain sounds okay reduce the +vowels ready okay we'll hear from the + + align:start position:0% +vowels ready okay we'll hear from the + + + align:start position:0% +vowels ready okay we'll hear from the +first group as loudly as + + align:start position:0% +first group as loudly as + + + align:start position:0% +first group as loudly as +possible he in + + align:start position:0% +possible he in + + + align:start position:0% +possible he in +Sp together at the same + + align:start position:0% +Sp together at the same + + + align:start position:0% +Sp together at the same +time one more time he Liv + + align:start position:0% +time one more time he Liv + + + align:start position:0% +time one more time he Liv +in okay everyone you have to pay + + align:start position:0% +in okay everyone you have to pay + + + align:start position:0% +in okay everyone you have to pay +attention is that is that good one more + + align:start position:0% +attention is that is that good one more + + + align:start position:0% +attention is that is that good one more +time + + align:start position:0% +time + + + align:start position:0% +time +he Liv + + align:start position:0% +he Liv + + + align:start position:0% +he Liv +in yes one more time he Liv and do we + + align:start position:0% +in yes one more time he Liv and do we + + + align:start position:0% +in yes one more time he Liv and do we +have the same do you have the do you + + align:start position:0% +have the same do you have the do you + + + align:start position:0% +have the same do you have the do you +have the correct rhythmic pattern he he + + align:start position:0% +have the correct rhythmic pattern he he + + + align:start position:0% +have the correct rhythmic pattern he he +lived in Spain he lived in Spain perfect + + align:start position:0% +lived in Spain he lived in Spain perfect + + + align:start position:0% +lived in Spain he lived in Spain perfect +very good very good thank + + align:start position:0% +very good very good thank + + + align:start position:0% +very good very good thank +you + + align:start position:0% +you + + + align:start position:0% +you +okay well and after you can you can + + align:start position:0% +okay well and after you can you can + + + align:start position:0% +okay well and after you can you can +write your sentence on the board now + + align:start position:0% +write your sentence on the board now + + + align:start position:0% +write your sentence on the board now +next everyone pay attention + + align:start position:0% + + + + align:start position:0% + +please she sat at home one more time she + + align:start position:0% +please she sat at home one more time she + + + align:start position:0% +please she sat at home one more time she +sat at home she sat at home she sat at + + align:start position:0% +sat at home she sat at home she sat at + + + align:start position:0% +sat at home she sat at home she sat at +home she's sad at home okay they have a + + align:start position:0% +home she's sad at home okay they have a + + + align:start position:0% +home she's sad at home okay they have a +flap there she's sad at home is that + + align:start position:0% +flap there she's sad at home is that + + + align:start position:0% +flap there she's sad at home is that +good sad at home she sad at home very + + align:start position:0% +good sad at home she sad at home very + + + align:start position:0% +good sad at home she sad at home very +good write your sentence in the board + + align:start position:0% +good write your sentence in the board + + + align:start position:0% +good write your sentence in the board +where your sent in the board and you can + + align:start position:0% +where your sent in the board and you can + + + align:start position:0% +where your sent in the board and you can +sit + + align:start position:0% + + + + align:start position:0% + +down next + + align:start position:0% + + + + align:start position:0% + +okay on three one two three they + + align:start position:0% +okay on three one two three they + + + align:start position:0% +okay on three one two three they +stop + + align:start position:0% + + + + align:start position:0% + +listen pay attention + + align:start position:0% +listen pay attention + + + align:start position:0% +listen pay attention +please one two three they stop talk they + + align:start position:0% +please one two three they stop talk they + + + align:start position:0% +please one two three they stop talk they +stop talk stop to talk they + + align:start position:0% +stop talk stop to talk they + + + align:start position:0% +stop talk stop to talk they +stop okay two two is a syllable they + + align:start position:0% +stop okay two two is a syllable they + + + align:start position:0% +stop okay two two is a syllable they +stop to talk they stop to talk to to to + + align:start position:0% +stop to talk they stop to talk to to to + + + align:start position:0% +stop to talk they stop to talk to to to +has a vow to they stop to talk it sounds + + align:start position:0% +has a vow to they stop to talk it sounds + + + align:start position:0% +has a vow to they stop to talk it sounds +like you don't have a vow they sto to + + align:start position:0% +like you don't have a vow they sto to + + + align:start position:0% +like you don't have a vow they sto to +they sto to talk one more + + align:start position:0% +they sto to talk one more + + + align:start position:0% +they sto to talk one more +time they sto the talk one two three + + align:start position:0% +time they sto the talk one two three + + + align:start position:0% +time they sto the talk one two three +they sto the talk they sto to talk they + + align:start position:0% +they sto the talk they sto to talk they + + + align:start position:0% +they sto the talk they sto to talk they +stop to to to is a vow there's a vow + + align:start position:0% +stop to to to is a vow there's a vow + + + align:start position:0% +stop to to to is a vow there's a vow +there they stop to + + align:start position:0% +there they stop to + + + align:start position:0% +there they stop to +talk they stop the + + align:start position:0% +talk they stop the + + + align:start position:0% +talk they stop the +talk say to they sto the talk they sto + + align:start position:0% +talk say to they sto the talk they sto + + + align:start position:0% +talk say to they sto the talk they sto +to they stop stopped to they stopped to + + align:start position:0% +to they stop stopped to they stopped to + + + align:start position:0% +to they stop stopped to they stopped to +talk they stopped to talk they stopped + + align:start position:0% +talk they stopped to talk they stopped + + + align:start position:0% +talk they stopped to talk they stopped +to talk they stopped to + + align:start position:0% +to talk they stopped to + + + align:start position:0% +to talk they stopped to +talk they stopped to talk they stopped + + align:start position:0% +talk they stopped to talk they stopped + + + align:start position:0% +talk they stopped to talk they stopped +to + + align:start position:0% + + + + align:start position:0% + +talk they stopped to talk very good they + + align:start position:0% +talk they stopped to talk very good they + + + align:start position:0% +talk they stopped to talk very good they +stopped to talk okay write your sentence + + align:start position:0% +stopped to talk okay write your sentence + + + align:start position:0% +stopped to talk okay write your sentence +on the + + align:start position:0% + + + + align:start position:0% + +board one 2 + + align:start position:0% +board one 2 + + + align:start position:0% +board one 2 +3 letter one 2 three she wrote a letter + + align:start position:0% +3 letter one 2 three she wrote a letter + + + align:start position:0% +3 letter one 2 three she wrote a letter +she wrote a slab is a little kind of she + + align:start position:0% +she wrote a slab is a little kind of she + + + align:start position:0% +she wrote a slab is a little kind of she +wrote a letter she wrote a letter she + + align:start position:0% +wrote a letter she wrote a letter she + + + align:start position:0% +wrote a letter she wrote a letter she +wrote a letter she wrote a + + align:start position:0% +wrote a letter she wrote a + + + align:start position:0% +wrote a letter she wrote a +letter + + align:start position:0% +letter + + + align:start position:0% +letter +letter this is very difficult because + + align:start position:0% +letter this is very difficult because + + + align:start position:0% +letter this is very difficult because +you have the L and R and the flap okay + + align:start position:0% +you have the L and R and the flap okay + + + align:start position:0% +you have the L and R and the flap okay +write your sentence on the board + + align:start position:0% +write your sentence on the board + + + align:start position:0% +write your sentence on the board +okay oh one two three ask question one + + align:start position:0% +okay oh one two three ask question one + + + align:start position:0% +okay oh one two three ask question one +two three ask + + align:start position:0% +two three ask + + + align:start position:0% +two three ask +question I don't I + + align:start position:0% + + + + align:start position:0% + +don't what 1 two + + align:start position:0% +don't what 1 two + + + align:start position:0% +don't what 1 two +three fish one okay together one two + + align:start position:0% + + + + align:start position:0% + +three okay but please write your write + + align:start position:0% +three okay but please write your write + + + align:start position:0% +three okay but please write your write +your sentence on the board we'll work on + + align:start position:0% +your sentence on the board we'll work on + + + align:start position:0% +your sentence on the board we'll work on +that together write your sentence on the + + align:start position:0% +that together write your sentence on the + + + align:start position:0% +that together write your sentence on the +board and put a check mark next to + + align:start position:0% +board and put a check mark next to + + + align:start position:0% +board and put a check mark next to +it meaning not good + + align:start position:0% + + + + align:start position:0% + +okay one two 3 I see what do you + + align:start position:0% +okay one two 3 I see what do you + + + align:start position:0% +okay one two 3 I see what do you +mean one 2 three I see + + align:start position:0% + + + + align:start position:0% + +mean + + align:start position:0% + + + + align:start position:0% + +no one more time one two three I see + + align:start position:0% +no one more time one two three I see + + + align:start position:0% +no one more time one two three I see +what you mean good what you what okay + + align:start position:0% +what you mean good what you what okay + + + align:start position:0% +what you mean good what you what okay +you have two options watch you you can + + align:start position:0% +you have two options watch you you can + + + align:start position:0% +you have two options watch you you can +you can you can palatalize it watch you + + align:start position:0% +you can you can palatalize it watch you + + + align:start position:0% +you can you can palatalize it watch you +or what you use a lot of stuff but you + + align:start position:0% +or what you use a lot of stuff but you + + + align:start position:0% +or what you use a lot of stuff but you +can't have a flap the first time you had + + align:start position:0% +can't have a flap the first time you had + + + align:start position:0% +can't have a flap the first time you had +a flap I see what you you had a flap + + align:start position:0% +a flap I see what you you had a flap + + + align:start position:0% +a flap I see what you you had a flap +right don't have a flap what you what + + align:start position:0% +right don't have a flap what you what + + + align:start position:0% +right don't have a flap what you what +you or what you one more time one two + + align:start position:0% +you or what you one more time one two + + + align:start position:0% +you or what you one more time one two +three I see what you mean very + + align:start position:0% +three I see what you mean very + + + align:start position:0% +three I see what you mean very +good I see what you mean where I see + + align:start position:0% +good I see what you mean where I see + + + align:start position:0% +good I see what you mean where I see +what you mean what you mean I think I + + align:start position:0% +what you mean what you mean I think I + + + align:start position:0% +what you mean what you mean I think I +mean I use a lot of stuff WR down on the + + align:start position:0% +mean I use a lot of stuff WR down on the + + + align:start position:0% +mean I use a lot of stuff WR down on the +board okay one two + + align:start position:0% +board okay one two + + + align:start position:0% +board okay one two + + align:start position:0% + + + 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align:start position:0% +thought you you we thought we thought we +thought you I I I use a GL stop we + + align:start position:0% +thought you I I I use a GL stop we + + + align:start position:0% +thought you I I I use a GL stop we +thought you sick we thought sick we + + align:start position:0% +thought you sick we thought sick we + + + align:start position:0% +thought you sick we thought sick we +thought you're sick we thought you sick + + align:start position:0% +thought you're sick we thought you sick + + + align:start position:0% +thought you're sick we thought you sick +we thought you're sick we thought you + + align:start position:0% +we thought you're sick we thought you + + + align:start position:0% +we thought you're sick we thought you +sick I see what you mean I see what you + + align:start position:0% +sick I see what you mean I see what you + + + align:start position:0% +sick I see what you mean I see what you +mean I see what you mean I see what you + + align:start 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+ + + align:start position:0% +one he lived in Spain lived in Spain he +lived in Spain lived in Spain this + + align:start position:0% +lived in Spain lived in Spain this + + + align:start position:0% +lived in Spain lived in Spain this +one she sat at home she at home she St + + align:start position:0% +one she sat at home she at home she St + + + align:start position:0% +one she sat at home she at home she St +at home she at home she St at home she + + align:start position:0% +at home she at home she St at home she + + + align:start position:0% +at home she at home she St at home she +at home becomes a flat + + align:start position:0% +at home becomes a flat + + + align:start position:0% +at home becomes a flat +here they stop + + align:start position:0% +here they stop + + + align:start position:0% +here they stop +to they stop to talk they stop to talk + + align:start position:0% + + + + align:start position:0% + +okay they + + align:start position:0% +okay they + + + align:start 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think + + + align:start position:0% +me stop I think I'm stopping I I think +I'm using a glot of stop here I they + + align:start position:0% +I'm using a glot of stop here I they + + + align:start position:0% +I'm using a glot of stop here I they +stop they stop they stop I think I have + + align:start position:0% +stop they stop they stop I think I have + + + align:start position:0% +stop they stop they stop I think I have +a stop but if you actually analyze it + + align:start position:0% +a stop but if you actually analyze it + + + align:start position:0% +a stop but if you actually analyze it +there might not be any difference they + + align:start position:0% +there might not be any difference they + + + align:start position:0% +there might not be any difference they +stop to talk there are two t here two t + + align:start position:0% +stop to talk there are two t here two t + + + align:start position:0% +stop to talk there are two t here two t +here right so get rid of one t stop 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a letter she wrote a letter she + + + align:start position:0% +wrote a letter she wrote a letter she +wrote a letter she wrote a letter she + + align:start position:0% +wrote a letter she wrote a letter she + + + align:start position:0% +wrote a letter she wrote a letter she +wrote a letter she wrote a letter wrote + + align:start position:0% +wrote a letter she wrote a letter wrote + + + align:start position:0% +wrote a letter she wrote a letter wrote +a this is a light L your tongue is + + align:start position:0% +a this is a light L your tongue is + + + align:start position:0% +a this is a light L your tongue is +really + + align:start position:0% +really + + + align:start position:0% +really +tense she wrote a letter wrote a letter + + align:start position:0% +tense she wrote a letter wrote a letter + + + align:start position:0% +tense she wrote a letter wrote a letter +she wrote a letter she wrote a letter + + align:start position:0% +she wrote a letter she wrote a letter + + + 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together you becomes two right + + + align:start position:0% +t and Y together you becomes two right +palent or use a GL stop and why what you + + align:start position:0% +palent or use a GL stop and why what you + + + align:start position:0% +palent or use a GL stop and why what you +okay what do you what do you not good + + align:start position:0% +okay what do you what do you not good + + + align:start position:0% +okay what do you what do you not good +what do you not + + align:start position:0% + + + + align:start position:0% + +good + + align:start position:0% + + + + align:start position:0% + +here so for inst + + align:start position:0% +here so for inst + + + align:start position:0% +here so for inst +what do you mean what do you mean what + + align:start position:0% +what do you mean what do you mean what + + + align:start position:0% +what do you mean what do you mean what +do you mean yes then then T and D it + + align:start position:0% +do you mean yes then then T and D it 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+ + align:start position:0% + +questions she said at home now again H + + align:start position:0% +questions she said at home now again H + + + align:start position:0% +questions she said at home now again H +is a consonant right so she sat she sat + + align:start position:0% +is a consonant right so she sat she sat + + + align:start position:0% +is a consonant right so she sat she sat +at home + + align:start position:0% +at home + + + align:start position:0% +at home +but she sad she sad at home she's sad at + + align:start position:0% +but she sad she sad at home she's sad at + + + align:start position:0% +but she sad she sad at home she's sad at +home I think this becomes a flap too + + align:start position:0% +home I think this becomes a flap too + + + align:start position:0% +home I think this becomes a flap too +actually she's sad at home she's sad at + + align:start position:0% +actually she's sad at home she's sad at + + + align:start position:0% +actually she's sad at home she's sad at +home she's sad at home she satad at + + align:start position:0% +home she's sad at home she satad at + + + align:start position:0% +home she's sad at home she satad at +homeed she sad to the + + align:start position:0% +homeed she sad to the + + + align:start position:0% +homeed she sad to the +but that that rule applies only to one + + align:start position:0% +but that that rule applies only to one + + + align:start position:0% +but that that rule applies only to one +one word not across two words not across + + align:start position:0% +one word not across two words not across + + + align:start position:0% +one word not across two words not across +to we had we had the same question last + + align:start position:0% +to we had we had the same question last + + + align:start position:0% +to we had we had the same question last +time + + align:start position:0% +time + + + align:start position:0% +time +right she sat at home she sat at home + + align:start position:0% +right she sat at home she sat at home + + + align:start position:0% +right she sat at home she sat at home +she sat at she sat she sat at home she + + align:start position:0% +she sat at she sat she sat at home she + + + align:start position:0% +she sat at she sat she sat at home she +sat at she sat at home she sat at home + + align:start position:0% +sat at she sat at home she sat at home + + + align:start position:0% +sat at she sat at home she sat at home +she sat at home she sat at home yes to + + align:start position:0% +she sat at home she sat at home yes to + + + align:start position:0% +she sat at home she sat at home yes to +me becomes like a flap she sat at + + align:start position:0% + + + + align:start position:0% + +home okay did I did I collect all the + + align:start position:0% +home okay did I did I collect all the + + + align:start position:0% +home okay did I did I collect all the +sentences + + align:start position:0% + + + + align:start position:0% + +back uh okay we just reviewed Rhythm any + + align:start position:0% +back uh okay we just reviewed Rhythm any + + + align:start position:0% +back uh okay we just reviewed Rhythm any +questions about Rhythm sentence stress + + align:start position:0% +questions about Rhythm sentence stress + + + align:start position:0% +questions about Rhythm sentence stress +and + + align:start position:0% +and + + + align:start position:0% +and +Rhythm okay now we're going to talk + + align:start position:0% +Rhythm okay now we're going to talk + + + align:start position:0% +Rhythm okay now we're going to talk +about unreal past conditional and after + + align:start position:0% +about unreal past conditional and after + + + align:start position:0% +about unreal past conditional and after +that we're going to talk we're going to + + align:start position:0% +that we're going to talk we're going to + + + align:start position:0% +that we're going to talk we're going to +start talking about prominence today um + + align:start position:0% +start talking about prominence today um + + + align:start position:0% +start talking about prominence today um +on Tuesday next week right Tuesday + + align:start position:0% +on Tuesday next week right Tuesday + + + align:start position:0% +on Tuesday next week right Tuesday +Tuesday after Tuesday we have a holiday + + align:start position:0% +Tuesday after Tuesday we have a holiday + + + align:start position:0% +Tuesday after Tuesday we have a holiday +on Thursday so after Tuesday I I get to + + align:start position:0% +on Thursday so after Tuesday I I get to + + + align:start position:0% +on Thursday so after Tuesday I I get to +say have a nice weekend after + + align:start position:0% +say have a nice weekend after + + + align:start position:0% +say have a nice weekend after +Tuesday now according to your schedule + + align:start position:0% +Tuesday now according to your schedule + + + align:start position:0% +Tuesday now according to your schedule +there should be an ADM quiz on Tuesday + + align:start position:0% +there should be an ADM quiz on Tuesday + + + align:start position:0% +there should be an ADM quiz on Tuesday +but no quiz on Tuesday we're going to + + align:start position:0% +but no quiz on Tuesday we're going to + + + align:start position:0% +but no quiz on Tuesday we're going to +have that uh the the following Tuesday + + align:start position:0% +have that uh the the following Tuesday + + + align:start position:0% +have that uh the the following Tuesday +okay uh but we will have our + + align:start position:0% + + + + align:start position:0% + +debate on Tuesday which means I want you + + align:start position:0% +debate on Tuesday which means I want you + + + align:start position:0% +debate on Tuesday which means I want you +to prepare for the debate uh so the two + + align:start position:0% +to prepare for the debate uh so the two + + + align:start position:0% +to prepare for the debate uh so the two +homework assignments for Tuesday is read + + align:start position:0% +homework assignments for Tuesday is read + + + align:start position:0% +homework assignments for Tuesday is read +uh big picture chapter 15 and prepare + + align:start position:0% +uh big picture chapter 15 and prepare + + + align:start position:0% +uh big picture chapter 15 and prepare +for the debate how do you prepare for + + align:start position:0% +for the debate how do you prepare for + + + align:start position:0% +for the debate how do you prepare for +the + + align:start position:0% +the + + + align:start position:0% +the +debate if you turn + + align:start position:0% + + + + align:start position:0% + +to page + + align:start position:0% +to page + + + align:start position:0% +to page +109 in your course packet page 109 + + align:start position:0% +109 in your course packet page 109 + + + align:start position:0% +109 in your course packet page 109 +discussion Gambit index + + align:start position:0% + + + + align:start position:0% + +card discussion Gambit index cards okay + + align:start position:0% +card discussion Gambit index cards okay + + + align:start position:0% +card discussion Gambit index cards okay +we have there is about here there's + + align:start position:0% +we have there is about here there's + + + align:start position:0% +we have there is about here there's +there are about 40 gambits here page 109 + + align:start position:0% +there are about 40 gambits here page 109 + + + align:start position:0% +there are about 40 gambits here page 109 +40 gambits 109 and 120 10 No No 109 and + + align:start position:0% +40 gambits 109 and 120 10 No No 109 and + + + align:start position:0% +40 gambits 109 and 120 10 No No 109 and + + align:start position:0% + + + align:start position:0% +right during the + + align:start position:0% +right during the + + + align:start position:0% +right during the +debate you need to participate at least + + align:start position:0% +debate you need to participate at least + + + align:start position:0% +debate you need to participate at least +twice you need to participate at least + + align:start position:0% +twice you need to participate at least + + + align:start position:0% +twice you need to participate at least +twice + + align:start position:0% +twice + + + align:start position:0% +twice +okay and you need to use at least three + + align:start position:0% +okay and you need to use at least three + + + align:start position:0% +okay and you need to use at least three +of these gambits during the debate okay + + align:start position:0% +of these gambits during the debate okay + + + align:start position:0% +of these gambits during the debate okay +we're going to play like a + + align:start position:0% +we're going to play like a + + + align:start position:0% +we're going to play like a +game on + + align:start position:0% + + + + align:start position:0% + +Tuesday so let's read this situation + + align:start position:0% +Tuesday so let's read this situation + + + align:start position:0% +Tuesday so let's read this situation +page 111 page + + align:start position:0% + + + + align:start position:0% + +111 page + + align:start position:0% +111 page + + + align:start position:0% +111 page +111 okay um let's let's go around the + + align:start position:0% +111 okay um let's let's go around the + + + align:start position:0% +111 okay um let's let's go around the +room and read one sentence each okay + + align:start position:0% +room and read one sentence each okay + + + align:start position:0% +room and read one sentence each okay +starting with y starting with Le is a + + align:start position:0% +starting with y starting with Le is a + + + align:start position:0% +starting with y starting with Le is a +foreign student on page 111 background + + align:start position:0% + + + + align:start position:0% + +information Le is a foreign student who + + align:start position:0% +information Le is a foreign student who + + + align:start position:0% +information Le is a foreign student who +has been in the United States over for + + align:start position:0% +has been in the United States over for + + + align:start position:0% +has been in the United States over for +over a year he's a freshman in high + + align:start position:0% +over a year he's a freshman in high + + + align:start position:0% +over a year he's a freshman in high +school okay we're going to change tatto + + align:start position:0% +school okay we're going to change tatto + + + align:start position:0% +school okay we're going to change tatto +he's a first year graduate student at + + align:start position:0% +he's a first year graduate student at + + + align:start position:0% +he's a first year graduate student at +MIT he's a first year graduate student + + align:start position:0% +MIT he's a first year graduate student + + + align:start position:0% +MIT he's a first year graduate student +at MIT okay next always good + + align:start position:0% + + + + align:start position:0% + +but + + align:start position:0% +but + + + align:start position:0% +but +H volunteered + + align:start position:0% +H volunteered + + + align:start position:0% +H volunteered +or talk in talking class not not + + align:start position:0% +or talk in talking class not not + + + align:start position:0% +or talk in talking class not not +talk + + align:start position:0% + + + + align:start position:0% + +CL + + align:start position:0% +CL + + + align:start position:0% +CL +the is very upset about the gra because + + align:start position:0% +the is very upset about the gra because + + + align:start position:0% +the is very upset about the gra because +he feels that he deserves at + + align:start position:0% +he feels that he deserves at + + + align:start position:0% +he feels that he deserves at +least + + align:start position:0% +least + + + align:start position:0% +least +also + + align:start position:0% + + + + align:start position:0% + +clear the problem is whether or not he + + align:start position:0% +clear the problem is whether or not he + + + align:start position:0% +clear the problem is whether or not he +should complain to the head of the + + align:start position:0% + + + + align:start position:0% + +department the + + align:start position:0% +department the + + + align:start position:0% +department the +department that becom + + align:start position:0% + + + + align:start position:0% + +AAP whatever you have and the and and + + align:start position:0% +AAP whatever you have and the and and + + + align:start position:0% +AAP whatever you have and the and and +try to get rid of the the of of the say + + align:start position:0% +try to get rid of the the of of the say + + + align:start position:0% +try to get rid of the the of of the say +of the of the that's going to make it a + + align:start position:0% +of the of the that's going to make it a + + + align:start position:0% +of the of the that's going to make it a +lot easier head of the department head + + align:start position:0% +lot easier head of the department head + + + align:start position:0% +lot easier head of the department head +of + + align:start position:0% + + + + align:start position:0% + +the the the the of the department + + align:start position:0% +the the the the of the department + + + align:start position:0% +the the the the of the department +okay the teacher has + + align:start position:0% +okay the teacher has + + + align:start position:0% +okay the teacher has +already + + align:start position:0% +already + + + align:start position:0% +already +consider + + align:start position:0% +consider + + + align:start position:0% +consider +okay in this native country the + + align:start position:0% +okay in this native country the + + + align:start position:0% +okay in this native country the +authority of the teacher is very + + align:start position:0% +authority of the teacher is very + + + align:start position:0% +authority of the teacher is very +challenged + + align:start position:0% + + + + align:start position:0% + +authority + + align:start position:0% + + + + align:start position:0% + +authority authority author Authority + + align:start position:0% +authority authority author Authority + + + align:start position:0% +authority authority author Authority +auth + + align:start position:0% +auth + + + align:start position:0% +auth +next uned States he has observed several + + align:start position:0% +next uned States he has observed several + + + align:start position:0% +next uned States he has observed several +students challenging the teachers + + align:start position:0% +students challenging the teachers + + + align:start position:0% +students challenging the teachers +authority authority authority authority + + align:start position:0% +authority authority authority authority + + + align:start position:0% +authority authority authority authority +next + + align:start position:0% +next + + + align:start position:0% +next +students simar + + align:start position:0% + + + + align:start position:0% + +problem next they asked Le to join them + + align:start position:0% + + + + align:start position:0% + +nexts + + align:start position:0% +nexts + + + align:start position:0% +nexts +may may have to may have to take another + + align:start position:0% +may may have to may have to take another + + + align:start position:0% +may may have to may have to take another +class with his teacher next next he must + + align:start position:0% +class with his teacher next next he must + + + align:start position:0% +class with his teacher next next he must +whether to Pro + + align:start position:0% +whether to Pro + + + align:start position:0% +whether to Pro +the + + align:start position:0% +the + + + align:start position:0% +the +or okay so this is a situation you have + + align:start position:0% +or okay so this is a situation you have + + + align:start position:0% +or okay so this is a situation you have +a number right one if you're number one + + align:start position:0% +a number right one if you're number one + + + align:start position:0% +a number right one if you're number one +you already have a number today right if + + align:start position:0% +you already have a number today right if + + + align:start position:0% +you already have a number today right if +you're number one you are going to say + + align:start position:0% +you're number one you are going to say + + + align:start position:0% +you're number one you are going to say +yes he should protest if you're number + + align:start position:0% +yes he should protest if you're number + + + align:start position:0% +yes he should protest if you're number +two no he should not protest okay I + + align:start position:0% +two no he should not protest okay I + + + align:start position:0% +two no he should not protest okay I +already I and think of some arguments + + align:start position:0% +already I and think of some arguments + + + align:start position:0% +already I and think of some arguments +okay so I I give you the + + align:start position:0% +okay so I I give you the + + + align:start position:0% +okay so I I give you the +position okay you need to think of + + align:start position:0% +position okay you need to think of + + + align:start position:0% +position okay you need to think of +arguments you remember your + + align:start position:0% +arguments you remember your + + + align:start position:0% +arguments you remember your +numbers do you all remember your numbers + + align:start position:0% +numbers do you all remember your numbers + + + align:start position:0% +numbers do you all remember your numbers +no okay so we're going to do one 2 one + + align:start position:0% +no okay so we're going to do one 2 one + + + align:start position:0% +no okay so we're going to do one 2 one +one more + + align:start position:0% + + + + align:start position:0% + +time one + + align:start position:0% + + + + align:start position:0% + +one okay + + align:start position:0% +one okay + + + align:start position:0% +one okay +number one is going to say yes he should + + align:start position:0% +number one is going to say yes he should + + + align:start position:0% +number one is going to say yes he should +protest number two no he should not + + align:start position:0% +protest number two no he should not + + + align:start position:0% +protest number two no he should not +protest should not + + align:start position:0% + + + + align:start position:0% + +protest is that clear C you need to + + align:start position:0% +protest is that clear C you need to + + + align:start position:0% +protest is that clear C you need to +participate at least twice you need to + + align:start position:0% +participate at least twice you need to + + + align:start position:0% +participate at least twice you need to +use at least three gambits so practice + + align:start position:0% +use at least three gambits so practice + + + align:start position:0% +use at least three gambits so practice +saying these gambits at home + + align:start position:0% + + + + align:start position:0% + +okay now let's turn to page + + align:start position:0% +okay now let's turn to page + + + align:start position:0% +okay now let's turn to page +95 oh actually + + align:start position:0% +95 oh actually + + + align:start position:0% +95 oh actually +before we do that I almost + + align:start position:0% +before we do that I almost + + + align:start position:0% +before we do that I almost +forgot + + align:start position:0% +forgot + + + align:start position:0% +forgot +uh one more thing I want to do about + + align:start position:0% +uh one more thing I want to do about + + + align:start position:0% +uh one more thing I want to do about +Rhythm turn to page 90 in your textbook + + align:start position:0% +Rhythm turn to page 90 in your textbook + + + align:start position:0% +Rhythm turn to page 90 in your textbook +accurate English page 90 page 90 + + align:start position:0% + + + + align:start position:0% + +page + + align:start position:0% + + + + align:start position:0% + +90 okay let's compare A and B how many + + align:start position:0% +90 okay let's compare A and B how many + + + align:start position:0% +90 okay let's compare A and B how many +how many content words does sentence a + + align:start position:0% +how many content words does sentence a + + + align:start position:0% +how many content words does sentence a +have how many content words one and that + + align:start position:0% +have how many content words one and that + + + align:start position:0% +have how many content words one and that +is two this one two + + align:start position:0% +is two this one two + + + align:start position:0% +is two this one two +two first one can't and do which one + + align:start position:0% +two first one can't and do which one + + + align:start position:0% +two first one can't and do which one +gets more + + align:start position:0% +gets more + + + align:start position:0% +gets more +stress no do do uh we haven't actually + + align:start position:0% +stress no do do uh we haven't actually + + + align:start position:0% +stress no do do uh we haven't actually +we haven't talked about this the last + + align:start position:0% +we haven't talked about this the last + + + align:start position:0% +we haven't talked about this the last +content work usually gets more stress + + align:start position:0% +content work usually gets more stress + + + align:start position:0% +content work usually gets more stress +first content work second content work + + align:start position:0% +first content work second content work + + + align:start position:0% +first content work second content work +there's more stress here why is this a + + align:start position:0% +there's more stress here why is this a + + + align:start position:0% +there's more stress here why is this a +Content word here not because of the + + align:start position:0% +Content word here not because of the + + + align:start position:0% +Content word here not because of the +negative whenever you have a negative it + + align:start position:0% +negative whenever you have a negative it + + + align:start position:0% +negative whenever you have a negative it +becomes a cont word right so what + + align:start position:0% +becomes a cont word right so what + + + align:start position:0% +becomes a cont word right so what +happens to The Vow + + align:start position:0% +happens to The Vow + + + align:start position:0% +happens to The Vow +here reduce right so we're going to + + align:start position:0% +here reduce right so we're going to + + + align:start position:0% +here reduce right so we're going to +say now it's it's + + align:start position:0% +say now it's it's + + + align:start position:0% +say now it's it's +not sh would be like but it's hair we + + align:start position:0% +not sh would be like but it's hair we + + + align:start position:0% +not sh would be like but it's hair we +usually use a I use a cabic + + align:start position:0% +usually use a I use a cabic + + + align:start position:0% +usually use a I use a cabic +again I can do it do I can do it + + align:start position:0% +again I can do it do I can do it + + + align:start position:0% +again I can do it do I can do it +here can't can't do + + align:start position:0% +here can't can't do + + + align:start position:0% +here can't can't do +it I can't do it do it I can't do it I + + align:start position:0% +it I can't do it do it I can't do it I + + + align:start position:0% +it I can't do it do it I can't do it I +can't do it I can do it I do it I can do + + align:start position:0% +can't do it I can do it I do it I can do + + + align:start position:0% +can't do it I can do it I do it I can do +it I can do it you can do it you can do + + align:start position:0% +it I can do it you can do it you can do + + + align:start position:0% +it I can do it you can do it you can do +it you can do it you can do + + align:start position:0% +it you can do it you can do + + + align:start position:0% +it you can do it you can do +it can do it I can do it you can do it + + align:start position:0% +it can do it I can do it you can do it + + + align:start position:0% +it can do it I can do it you can do it +you can do it it very + + align:start position:0% + + + + align:start position:0% + +good you can do it you can do it you + + align:start position:0% +good you can do it you can do it you + + + align:start position:0% +good you can do it you can do it you +don't want to say you can't do it if you + + align:start position:0% +don't want to say you can't do it if you + + + align:start position:0% +don't want to say you can't do it if you +say you can't do it then + + align:start position:0% +say you can't do it then + + + align:start position:0% +say you can't do it then +well we get confused you can't do it + + align:start position:0% +well we get confused you can't do it + + + align:start position:0% +well we get confused you can't do it +what do you mean can can this one can + + align:start position:0% +what do you mean can can this one can + + + align:start position:0% +what do you mean can can this one can +can't do it you can't do it you have to + + align:start position:0% +can't do it you can't do it you have to + + + align:start position:0% +can't do it you can't do it you have to +you can do it + + align:start position:0% +you can do it + + + align:start position:0% +you can do it +okay first one I do it I can do it very + + align:start position:0% +okay first one I do it I can do it very + + + align:start position:0% +okay first one I do it I can do it very +good I can do it I can do it I can do it + + align:start position:0% +good I can do it I can do it I can do it + + + align:start position:0% +good I can do it I can do it I can do it +is very important I can do it one I do + + align:start position:0% +is very important I can do it one I do + + + align:start position:0% +is very important I can do it one I do +it one more time I do it it very good + + align:start position:0% +it one more time I do it it very good + + + align:start position:0% +it one more time I do it it very good +okay you can do it you can do it you can + + align:start position:0% +okay you can do it you can do it you can + + + align:start position:0% +okay you can do it you can do it you can +do it you can do it you can do it you + + align:start position:0% +do it you can do it you can do it you + + + align:start position:0% +do it you can do it you can do it you +can do it do not + + align:start position:0% +can do it do not + + + align:start position:0% +can do it do not +you can do it you can do it you can do + + align:start position:0% +you can do it you can do it you can do + + + align:start position:0% +you can do it you can do it you can do +it you can do it then then the listener + + align:start position:0% +it you can do it then then the listener + + + align:start position:0% +it you can do it then then the listener +gets really confused + + align:start position:0% + + + + align:start position:0% + +okay let's turn to page + + align:start position:0% +okay let's turn to page + + + align:start position:0% +okay let's turn to page +90 page + + align:start position:0% + + + + align:start position:0% + +90 okay so ABC the speaker + + align:start position:0% +90 okay so ABC the speaker + + + align:start position:0% +90 okay so ABC the speaker +used right I can swim I can you can hear + + align:start position:0% +used right I can swim I can you can hear + + + align:start position:0% +used right I can swim I can you can hear +the noise + + align:start position:0% +the noise + + + align:start position:0% +the noise +Shar can speak English speak English + + align:start position:0% +Shar can speak English speak English + + + align:start position:0% +Shar can speak English speak English +Okay + + align:start position:0% + + + + align:start position:0% + +question + + align:start position:0% +question + + + align:start position:0% +question +can no no they said she said can but d + + align:start position:0% +can no no they said she said can but d + + + align:start position:0% +can no no they said she said can but d +and e can you help me can can second one + + align:start position:0% +and e can you help me can can second one + + + align:start position:0% +and e can you help me can can second one +can you help me can you can you help me + + align:start position:0% +can you help me can you can you help me + + + align:start position:0% +can you help me can you can you help me +can you help me can you help me sounds + + align:start position:0% +can you help me can you help me sounds + + + align:start position:0% +can you help me can you help me sounds +really + + align:start position:0% +really + + + align:start position:0% +really +odd can you help me can you help can you + + align:start position:0% +odd can you help me can you help can you + + + align:start position:0% +odd can you help me can you help can you +help me where can we meet can we meet + + align:start position:0% +help me where can we meet can we meet + + + align:start position:0% +help me where can we meet can we meet +okay so in in a question you usually say + + align:start position:0% +okay so in in a question you usually say + + + align:start position:0% +okay so in in a question you usually say +can in a affirmative sentence usually we + + align:start position:0% +can in a affirmative sentence usually we + + + align:start position:0% +can in a affirmative sentence usually we +say + + align:start position:0% + + + + align:start position:0% + +Okay okay + + align:start position:0% +Okay okay + + + align:start position:0% +Okay okay +so negative with if you have not you + + align:start position:0% +so negative with if you have not you + + + align:start position:0% +so negative with if you have not you +have to say can or can use a CL stop or + + align:start position:0% +have to say can or can use a CL stop or + + + align:start position:0% +have to say can or can use a CL stop or +can't or can all right and if it comes + + align:start position:0% +can't or can all right and if it comes + + + align:start position:0% +can't or can all right and if it comes +at the end of a word word you can't say + + align:start position:0% +at the end of a word word you can't say + + + align:start position:0% +at the end of a word word you can't say +could yes I can you have to say yes I + + align:start position:0% +could yes I can you have to say yes I + + + align:start position:0% +could yes I can you have to say yes I +can you can't say yes I could it sounds + + align:start position:0% +can you can't say yes I could it sounds + + + align:start position:0% +can you can't say yes I could it sounds +really funny okay do do you you know + + align:start position:0% +really funny okay do do you you know + + + align:start position:0% +really funny okay do do you you know +this movie Catch Me If You Can Catch Me + + align:start position:0% +this movie Catch Me If You Can Catch Me + + + align:start position:0% +this movie Catch Me If You Can Catch Me +If You Can okay you you say catch me she + + align:start position:0% +If You Can okay you you say catch me she + + + align:start position:0% +If You Can okay you you say catch me she +couldn't that's not good + + align:start position:0% +couldn't that's not good + + + align:start position:0% +couldn't that's not good +okay so what is difference number two + + align:start position:0% +okay so what is difference number two + + + align:start position:0% +okay so what is difference number two +and number three number two two + + align:start position:0% +and number three number two two + + + align:start position:0% +and number three number two two +negative and + + align:start position:0% +negative and + + + align:start position:0% +negative and +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +number two and number three yeah because + + align:start position:0% +number two and number three yeah because + + + align:start position:0% +number two and number three yeah because +the sound is + + align:start position:0% +the sound is + + + align:start position:0% +the sound is +SAR they are similar but not the same + + align:start position:0% +SAR they are similar but not the same + + + align:start position:0% +SAR they are similar but not the same +not the + + align:start position:0% +not the + + + align:start position:0% +not the +same it's yeah for me it's very hard to + + align:start position:0% +same it's yeah for me it's very hard to + + + align:start position:0% +same it's yeah for me it's very hard to +distinguish distinguish because there's + + align:start position:0% +distinguish distinguish because there's + + + align:start position:0% +distinguish distinguish because there's +a can't can't I can't that's the GL stop + + align:start position:0% +a can't can't I can't that's the GL stop + + + align:start position:0% +a can't can't I can't that's the GL stop +problem GL stop I can't do it I can't do + + align:start position:0% +problem GL stop I can't do it I can't do + + + align:start position:0% +problem GL stop I can't do it I can't do +it I can't there's a there's a SED stop + + align:start position:0% +it I can't there's a there's a SED stop + + + align:start position:0% +it I can't there's a there's a SED stop +here I can't do it I can't do it so how + + align:start position:0% +here I can't do it I can't do it so how + + + align:start position:0% +here I can't do it I can't do it so how +how can I understand the + + align:start position:0% +how can I understand the + + + align:start position:0% +how can I understand the +difference from + + align:start position:0% +difference from + + + align:start position:0% +difference from +the or how can you understand what + + align:start position:0% +the or how can you understand what + + + align:start position:0% +the or how can you understand what +difference difference in like in what + + align:start position:0% +difference difference in like in what + + + align:start position:0% +difference difference in like in what +example for example um number l or what + + align:start position:0% +example for example um number l or what + + + align:start position:0% +example for example um number l or what +what can we do what can we do and what + + align:start position:0% +what can we do what can we do and what + + + align:start position:0% +what can we do what can we do and what +can't we do okay so the difference will + + align:start position:0% +can't we do okay so the difference will + + + align:start position:0% +can't we do okay so the difference will +be what can we do what what can we do + + align:start position:0% +be what can we do what what can we do + + + align:start position:0% +be what can we do what what can we do +what can what can we do what + + align:start position:0% +what can what can we do what + + + align:start position:0% +what can what can we do what +what okay can't what have what can't + + align:start position:0% +what okay can't what have what can't + + + align:start position:0% +what okay can't what have what can't +what can't we do what can't we do can't + + align:start position:0% +what can't we do what can't we do can't + + + align:start position:0% +what can't we do what can't we do can't +there's a slight stop there stop there + + align:start position:0% +there's a slight stop there stop there + + + align:start position:0% +there's a slight stop there stop there +so it's actually yeah it's very similar + + align:start position:0% +so it's actually yeah it's very similar + + + align:start position:0% +so it's actually yeah it's very similar +but not not the same what can't we do + + align:start position:0% +but not not the same what can't we do + + + align:start position:0% +but not not the same what can't we do +can't can't what can't we do what can we + + align:start position:0% +can't can't what can't we do what can we + + + align:start position:0% +can't can't what can't we do what can we +do what can we do what can we do what + + align:start position:0% +do what can we do what can we do what + + + align:start position:0% +do what can we do what can we do what +can we do what can't we do what can't + + align:start position:0% +can we do what can't we do what can't + + + align:start position:0% +can we do what can't we do what can't +can't we do what can't we do what can't + + align:start position:0% +can't we do what can't we do what can't + + + align:start position:0% +can't we do what can't we do what can't +we do what can we do yeah sometimes and + + align:start position:0% +we do what can we do yeah sometimes and + + + align:start position:0% +we do what can we do yeah sometimes and +some times you you don't hear that so + + align:start position:0% +some times you you don't hear that so + + + align:start position:0% +some times you you don't hear that so +you ask what do you mean can or cannot + + align:start position:0% +you ask what do you mean can or cannot + + + align:start position:0% +you ask what do you mean can or cannot +okay you could you could ask him you + + align:start position:0% +okay you could you could ask him you + + + align:start position:0% +okay you could you could ask him you +could ask the speaker but it's very + + align:start position:0% +could ask the speaker but it's very + + + align:start position:0% +could ask the speaker but it's very +difficult what can't what can't we do + + align:start position:0% +difficult what can't what can't we do + + + align:start position:0% +difficult what can't what can't we do +they're not the same but similar what + + align:start position:0% +they're not the same but similar what + + + align:start position:0% +they're not the same but similar what +can't we do there's a stop what can't we + + align:start position:0% +can't we do there's a stop what can't we + + + align:start position:0% +can't we do there's a stop what can't we +can't we do okay lot of stop + + align:start position:0% +can't we do okay lot of stop + + + align:start position:0% +can't we do okay lot of stop +there about letter i m explain + + align:start position:0% + + + + align:start position:0% + +why letter I and your question again + + align:start position:0% +why letter I and your question again + + + align:start position:0% +why letter I and your question again +there + + align:start position:0% + + + + align:start position:0% + +is yeah and can't you do anything about + + align:start position:0% + + + + align:start position:0% + +it I don't know I don't there should be + + align:start position:0% +it I don't know I don't there should be + + + align:start position:0% +it I don't know I don't there should be +uh that's a very good question there + + align:start position:0% +uh that's a very good question there + + + align:start position:0% +uh that's a very good question there +should not be any stress here right + + align:start position:0% +should not be any stress here right + + + align:start position:0% +should not be any stress here right +because about is a + + align:start position:0% +because about is a + + + align:start position:0% +because about is a +preposition can do anything about + + align:start position:0% +preposition can do anything about + + + align:start position:0% +preposition can do anything about +it I would consider this a mistake + + align:start position:0% + + + + align:start position:0% + +no let me think about that but that's a + + align:start position:0% +no let me think about that but that's a + + + align:start position:0% +no let me think about that but that's a +very good question very good + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +question what number what letter I I so + + align:start position:0% +question what number what letter I I so + + + align:start position:0% +question what number what letter I I so +you can do either can you or can you I + + align:start position:0% +you can do either can you or can you I + + + align:start position:0% +you can do either can you or can you I +me stress stress is can for example do + + align:start position:0% +me stress stress is can for example do + + + align:start position:0% +me stress stress is can for example do +you speak English or do you speak + + align:start position:0% +you speak English or do you speak + + + align:start position:0% +you speak English or do you speak +English no do you speak + + align:start position:0% +English no do you speak + + + align:start position:0% +English no do you speak +English not do you do you speak English + + align:start position:0% +English not do you do you speak English + + + align:start position:0% +English not do you do you speak English +the stress is English do you speak + + align:start position:0% +the stress is English do you speak + + + align:start position:0% +the stress is English do you speak +Engish so can't you can't you do + + align:start position:0% +Engish so can't you can't you do + + + align:start position:0% +Engish so can't you can't you do +anything about it can't you do anything + + align:start position:0% +anything about it can't you do anything + + + align:start position:0% +anything about it can't you do anything +about + + align:start position:0% +about + + + align:start position:0% +about +it yeah the stress marks they they're + + align:start position:0% +it yeah the stress marks they they're + + + align:start position:0% +it yeah the stress marks they they're +putting stress marks on every content + + align:start position:0% +putting stress marks on every content + + + align:start position:0% +putting stress marks on every content +words here every content word here we're + + align:start position:0% +words here every content word here we're + + + align:start position:0% +words here every content word here we're +not talking about intonation intonation + + align:start position:0% +not talking about intonation intonation + + + align:start position:0% +not talking about intonation intonation +is something that we're going to talk + + align:start position:0% +is something that we're going to talk + + + align:start position:0% +is something that we're going to talk +about after we talk about permanence + + align:start position:0% +about after we talk about permanence + + + align:start position:0% +about after we talk about permanence +okay or today I'll I I'll talk about uh + + align:start position:0% +okay or today I'll I I'll talk about uh + + + align:start position:0% +okay or today I'll I I'll talk about uh +intonation a little + + align:start position:0% +intonation a little + + + align:start position:0% +intonation a little +bit + + align:start position:0% + + + + align:start position:0% + +uh maybe we + + align:start position:0% +uh maybe we + + + align:start position:0% +uh maybe we +should let's talk about prominence now + + align:start position:0% +should let's talk about prominence now + + + align:start position:0% +should let's talk about prominence now +okay since that question came up + + align:start position:0% +okay since that question came up + + + align:start position:0% +okay since that question came up +okay let's turn + + align:start position:0% + + + + align:start position:0% + +to okay in your course + + align:start position:0% + + + + align:start position:0% + +packet this is course packet + + align:start position:0% + + + + align:start position:0% + +page 74 74 page 74 + + align:start position:0% + + + + align:start position:0% + +page + + align:start position:0% + + + + align:start position:0% + + + align:start position:0% + + + + align:start position:0% + +uh + + align:start position:0% +uh + + + align:start position:0% +uh +now so Rhythm we talked + + align:start position:0% +now so Rhythm we talked + + + align:start position:0% +now so Rhythm we talked +about here when we talked about Rhythm + + align:start position:0% +about here when we talked about Rhythm + + + align:start position:0% +about here when we talked about Rhythm +uh we learned the fact that we need to + + align:start position:0% +uh we learned the fact that we need to + + + align:start position:0% +uh we learned the fact that we need to +stress the content + + align:start position:0% +stress the content + + + align:start position:0% +stress the content +words but no stress on function words + + align:start position:0% +words but no stress on function words + + + align:start position:0% +words but no stress on function words +right but if you put stress equal stress + + align:start position:0% +right but if you put stress equal stress + + + align:start position:0% +right but if you put stress equal stress +on all content words then it becomes + + align:start position:0% + + + + align:start position:0% + +to and nobody speaks that way unless I + + align:start position:0% +to and nobody speaks that way unless I + + + align:start position:0% +to and nobody speaks that way unless I +mean we uh during the interview when you + + align:start position:0% +mean we uh during the interview when you + + + align:start position:0% +mean we uh during the interview when you +slow down when the person Robert seagull + + align:start position:0% +slow down when the person Robert seagull + + + align:start position:0% +slow down when the person Robert seagull +slow down a bruise A bruise or a + + align:start position:0% + + + + align:start position:0% + +cut a bruise or a + + align:start position:0% +cut a bruise or a + + + align:start position:0% +cut a bruise or a +cut but in a fast regular speech nobody + + align:start position:0% +cut but in a fast regular speech nobody + + + align:start position:0% +cut but in a fast regular speech nobody +really speaks that way right so there is + + align:start position:0% +really speaks that way right so there is + + + align:start position:0% +really speaks that way right so there is +some stress on each content word but one + + align:start position:0% +some stress on each content word but one + + + align:start position:0% +some stress on each content word but one +word gets the most stress strongest + + align:start position:0% +word gets the most stress strongest + + + align:start position:0% +word gets the most stress strongest +stress and that element is called + + align:start position:0% +stress and that element is called + + + align:start position:0% +stress and that element is called +prominent element or prominence okay so + + align:start position:0% +prominent element or prominence okay so + + + align:start position:0% +prominent element or prominence okay so +that's one thing that we need to think + + align:start position:0% +that's one thing that we need to think + + + align:start position:0% +that's one thing that we need to think +about another + + align:start position:0% +about another + + + align:start position:0% +about another +thing is sometimes + + align:start position:0% + + + + align:start position:0% + +I the pronoun I is a Content word or a + + align:start position:0% +I the pronoun I is a Content word or a + + + align:start position:0% +I the pronoun I is a Content word or a +function + + align:start position:0% + + + + align:start position:0% + +word function it's a function word + + align:start position:0% +word function it's a function word + + + align:start position:0% +word function it's a function word +pronouns are function words okay read + + align:start position:0% +pronouns are function words okay read + + + align:start position:0% +pronouns are function words okay read +this + + align:start position:0% + + + + align:start position:0% + +eyes italicize because there's more + + align:start position:0% +eyes italicize because there's more + + + align:start position:0% +eyes italicize because there's more +emphasis here why is it important for + + align:start position:0% +emphasis here why is it important for + + + align:start position:0% +emphasis here why is it important for +today's kids to learn algebra because I + + align:start position:0% +today's kids to learn algebra because I + + + align:start position:0% +today's kids to learn algebra because I +had to learn this junk in school and now + + align:start position:0% +had to learn this junk in school and now + + + align:start position:0% +had to learn this junk in school and now +it's your turn that's why because I had + + align:start position:0% +it's your turn that's why because I had + + + align:start position:0% +it's your turn that's why because I had +to turn I had this is funny okay good + + align:start position:0% +to turn I had this is funny okay good + + + align:start position:0% +to turn I had this is funny okay good +now finally I have one cartoon that's + + align:start position:0% +now finally I have one cartoon that's + + + align:start position:0% +now finally I have one cartoon that's +funny because I had to learn I I'm + + align:start position:0% +funny because I had to learn I I'm + + + align:start position:0% +funny because I had to learn I I'm +emphasizing I and the difference I had + + align:start position:0% +emphasizing I and the difference I had + + + align:start position:0% +emphasizing I and the difference I had +to learn it so you have to learn it too + + align:start position:0% +to learn it so you have to learn it too + + + align:start position:0% +to learn it so you have to learn it too +okay so now in in some situations you + + align:start position:0% +okay so now in in some situations you + + + align:start position:0% +okay so now in in some situations you +want to emphasize uh certain uh content + + align:start position:0% +want to emphasize uh certain uh content + + + align:start position:0% +want to emphasize uh certain uh content +words no no no no function words okay + + align:start position:0% +words no no no no function words okay + + + align:start position:0% +words no no no no function words okay +and if you switch the uh stress it + + align:start position:0% +and if you switch the uh stress it + + + align:start position:0% +and if you switch the uh stress it +changes the + + align:start position:0% + + + + align:start position:0% + +meaning so review you can read that + + align:start position:0% +meaning so review you can read that + + + align:start position:0% +meaning so review you can read that +one thing that we need to talk about + + align:start position:0% +one thing that we need to talk about + + + align:start position:0% +one thing that we need to talk about +before we start talking about prominence + + align:start position:0% +before we start talking about prominence + + + align:start position:0% +before we start talking about prominence +is thought groups or it's uh in your + + align:start position:0% +is thought groups or it's uh in your + + + align:start position:0% +is thought groups or it's uh in your +book it's called pause groups and some + + align:start position:0% +book it's called pause groups and some + + + align:start position:0% +book it's called pause groups and some +other some people call it ination + + align:start position:0% +other some people call it ination + + + align:start position:0% +other some people call it ination +groups these + + align:start position:0% +groups these + + + align:start position:0% +groups these +are you you pause after a thought group + + align:start position:0% +are you you pause after a thought group + + + align:start position:0% +are you you pause after a thought group +and the the the the the phrases are + + align:start position:0% +and the the the the the phrases are + + + align:start position:0% +and the the the the the phrases are +long if you speak fast right if you + + align:start position:0% +long if you speak fast right if you + + + align:start position:0% +long if you speak fast right if you +speak really slowly in a public speech + + align:start position:0% +speak really slowly in a public speech + + + align:start position:0% +speak really slowly in a public speech +then they are short right so that they + + align:start position:0% +then they are short right so that they + + + align:start position:0% +then they are short right so that they +actually differ the + + align:start position:0% +actually differ the + + + align:start position:0% +actually differ the +lengths and they're grammatically and + + align:start position:0% +lengths and they're grammatically and + + + align:start position:0% +lengths and they're grammatically and +semantically coherent they have to be + + align:start position:0% +semantically coherent they have to be + + + align:start position:0% +semantically coherent they have to be +some sort of phrases like if you have a + + align:start position:0% +some sort of phrases like if you have a + + + align:start position:0% +some sort of phrases like if you have a +very long subject the guy that I met + + align:start position:0% +very long subject the guy that I met + + + align:start position:0% +very long subject the guy that I met +yesterday then you would stop there + + align:start position:0% +yesterday then you would stop there + + + align:start position:0% +yesterday then you would stop there +because we have + + align:start position:0% +because we have + + + align:start position:0% +because we have +a actually goes to mit2 so you actually + + align:start position:0% +a actually goes to mit2 so you actually + + + align:start position:0% +a actually goes to mit2 so you actually +stop after the long subject okay so you + + align:start position:0% +stop after the long subject okay so you + + + align:start position:0% +stop after the long subject okay so you +can stop after long subject or stop + + align:start position:0% +can stop after long subject or stop + + + align:start position:0% +can stop after long subject or stop +after the whole sentence or a complete + + align:start position:0% +after the whole sentence or a complete + + + align:start position:0% +after the whole sentence or a complete +or one pral + + align:start position:0% +or one pral + + + align:start position:0% +or one pral +phrase are often set up by pauses but + + align:start position:0% +phrase are often set up by pauses but + + + align:start position:0% +phrase are often set up by pauses but +not all the time sometimes you + + align:start position:0% +not all the time sometimes you + + + align:start position:0% +not all the time sometimes you +completely pause sometimes you kind of + + align:start position:0% +completely pause sometimes you kind of + + + align:start position:0% +completely pause sometimes you kind of +slow down you lengthen the final + + align:start position:0% +slow down you lengthen the final + + + align:start position:0% +slow down you lengthen the final +syllable + + align:start position:0% +syllable + + + align:start position:0% +syllable +okay in each thought group there's one + + align:start position:0% +okay in each thought group there's one + + + align:start position:0% +okay in each thought group there's one +prominent element what does prominent + + align:start position:0% +prominent element what does prominent + + + align:start position:0% +prominent element what does prominent +element mean in each thought group every + + align:start position:0% +element mean in each thought group every + + + align:start position:0% +element mean in each thought group every +content word will get some sort of + + align:start position:0% +content word will get some sort of + + + align:start position:0% +content word will get some sort of +stress what does that mean the vales in + + align:start position:0% +stress what does that mean the vales in + + + align:start position:0% +stress what does that mean the vales in +those words are not going to be reduced + + align:start position:0% +those words are not going to be reduced + + + align:start position:0% +those words are not going to be reduced +that's what it means some sort of stress + + align:start position:0% +that's what it means some sort of stress + + + align:start position:0% +that's what it means some sort of stress +means the vales are not going to be + + align:start position:0% +means the vales are not going to be + + + align:start position:0% +means the vales are not going to be +reduced function words the vals are + + align:start position:0% +reduced function words the vals are + + + align:start position:0% +reduced function words the vals are +going to be reduced because no stress + + align:start position:0% +going to be reduced because no stress + + + align:start position:0% +going to be reduced because no stress +but there's one word that's going to get + + align:start position:0% +but there's one word that's going to get + + + align:start position:0% +but there's one word that's going to get +the most stress that's where you go up + + align:start position:0% +the most stress that's where you go up + + + align:start position:0% +the most stress that's where you go up +okay so in English the most common + + align:start position:0% +okay so in English the most common + + + align:start position:0% +okay so in English the most common +intonation pattern + + align:start position:0% +intonation pattern + + + align:start position:0% +intonation pattern +is okay you keep + + align:start position:0% +is okay you keep + + + align:start position:0% +is okay you keep +flat not + + align:start position:0% +flat not + + + align:start position:0% +flat not +uh very common mistake + + align:start position:0% +uh very common mistake + + + align:start position:0% +uh very common mistake +I like it I people do that all the + + align:start position:0% +I like it I people do that all the + + + align:start position:0% +I like it I people do that all the +time okay it has its own ination pattern + + align:start position:0% +time okay it has its own ination pattern + + + align:start position:0% +time okay it has its own ination pattern +and linking and blending blending occur + + align:start position:0% +and linking and blending blending occur + + + align:start position:0% +and linking and blending blending occur +within at this not across usually + + align:start position:0% +within at this not across usually + + + align:start position:0% +within at this not across usually +thought groups when you pause after a + + align:start position:0% +thought groups when you pause after a + + + align:start position:0% +thought groups when you pause after a +thought group you can't have linking but + + align:start position:0% +thought group you can't have linking but + + + align:start position:0% +thought group you can't have linking but +if you when you just slow down you can + + align:start position:0% +if you when you just slow down you can + + + align:start position:0% +if you when you just slow down you can +have linking okay if you just slow + + align:start position:0% + + + + align:start position:0% + +down okay there there four four + + align:start position:0% +down okay there there four four + + + align:start position:0% +down okay there there four four +different four levels of s stress + + align:start position:0% +different four levels of s stress + + + align:start position:0% +different four levels of s stress +unstressed syllable right there's + + align:start position:0% +unstressed syllable right there's + + + align:start position:0% +unstressed syllable right there's +lightly stressed syllable all content + + align:start position:0% +lightly stressed syllable all content + + + align:start position:0% +lightly stressed syllable all content +Words which means no reduced vals number + + align:start position:0% +Words which means no reduced vals number + + + align:start position:0% +Words which means no reduced vals number +one unstress LEL reduced vals number + + align:start position:0% +one unstress LEL reduced vals number + + + align:start position:0% +one unstress LEL reduced vals number +two uh lightly stressed no reduced vals + + align:start position:0% +two uh lightly stressed no reduced vals + + + align:start position:0% +two uh lightly stressed no reduced vals +in strongly + + align:start position:0% +in strongly + + + align:start position:0% +in strongly +reduced strongly stressed that's the + + align:start position:0% +reduced strongly stressed that's the + + + align:start position:0% +reduced strongly stressed that's the +prominent element right and we have + + align:start position:0% +prominent element right and we have + + + align:start position:0% +prominent element right and we have +extra strong contrastive or lymphatic + + align:start position:0% +extra strong contrastive or lymphatic + + + align:start position:0% +extra strong contrastive or lymphatic +Str sometimes you're voice goes really + + align:start position:0% + + + + align:start position:0% + +high this sentence we have three words + + align:start position:0% +high this sentence we have three words + + + align:start position:0% +high this sentence we have three words +here I am listening + + align:start position:0% +here I am listening + + + align:start position:0% +here I am listening +if if I were to ask + + align:start position:0% +if if I were to ask + + + align:start position:0% +if if I were to ask +you uh what are you do like what are you + + align:start position:0% +you uh what are you do like what are you + + + align:start position:0% +you uh what are you do like what are you +doing are you + + align:start position:0% +doing are you + + + align:start position:0% +doing are you +listening what are you do are you + + align:start position:0% +listening what are you do are you + + + align:start position:0% +listening what are you do are you +listening yes yes I'm listening right + + align:start position:0% +listening yes yes I'm listening right + + + align:start position:0% +listening yes yes I'm listening right +what the stress would go where here yes + + align:start position:0% +what the stress would go where here yes + + + align:start position:0% +what the stress would go where here yes +I'm + + align:start position:0% +I'm + + + align:start position:0% +I'm +listening what are you doing are you + + align:start position:0% +listening what are you doing are you + + + align:start position:0% +listening what are you doing are you +listening yes I'm listening I'm + + align:start position:0% +listening yes I'm listening I'm + + + align:start position:0% +listening yes I'm listening I'm +listening I'm listening I'm listening + + align:start position:0% +listening I'm listening I'm listening + + + align:start position:0% +listening I'm listening I'm listening +right what are you doing what are you + + align:start position:0% +right what are you doing what are you + + + align:start position:0% +right what are you doing what are you +doing I'm listening I'm listening + + align:start position:0% +doing I'm listening I'm listening + + + align:start position:0% +doing I'm listening I'm listening +right if I + + align:start position:0% +right if I + + + align:start position:0% +right if I +said who's + + align:start position:0% +said who's + + + align:start position:0% +said who's +listening then you you you would + + align:start position:0% +listening then you you you would + + + align:start position:0% +listening then you you you would +say I'm listening I'm listening is + + align:start position:0% +say I'm listening I'm listening is + + + align:start position:0% +say I'm listening I'm listening is +anybody listening who's listening I'm + + align:start position:0% +anybody listening who's listening I'm + + + align:start position:0% +anybody listening who's listening I'm +listening right I'm + + align:start position:0% +listening right I'm + + + align:start position:0% +listening right I'm +listening so if you stress I'm listening + + align:start position:0% +listening so if you stress I'm listening + + + align:start position:0% +listening so if you stress I'm listening +then that's an answer + + align:start position:0% +then that's an answer + + + align:start position:0% +then that's an answer +to what's going on here you guys are + + align:start position:0% +to what's going on here you guys are + + + align:start position:0% +to what's going on here you guys are +having a party this is class time okay + + align:start position:0% +having a party this is class time okay + + + align:start position:0% +having a party this is class time okay +now if you say I'm + + align:start position:0% +now if you say I'm + + + align:start position:0% +now if you say I'm +listening that's an answer to a question + + align:start position:0% +listening that's an answer to a question + + + align:start position:0% +listening that's an answer to a question +like what are you doing what are you + + align:start position:0% +like what are you doing what are you + + + align:start position:0% +like what are you doing what are you +doing are you listening right but if you + + align:start position:0% +doing are you listening right but if you + + + align:start position:0% +doing are you listening right but if you +say I'm listening that's an answer to a + + align:start position:0% +say I'm listening that's an answer to a + + + align:start position:0% +say I'm listening that's an answer to a +question like who's listening so if you + + align:start position:0% +question like who's listening so if you + + + align:start position:0% +question like who's listening so if you +switch the stress it actually becomes a + + align:start position:0% +switch the stress it actually becomes a + + + align:start position:0% +switch the stress it actually becomes a +different different uh it has a + + align:start position:0% +different different uh it has a + + + align:start position:0% +different different uh it has a +different meaning when would you say can + + align:start position:0% +different meaning when would you say can + + + align:start position:0% +different meaning when would you say can +you stress the verb here the the beaver + + align:start position:0% +you stress the verb here the the beaver + + + align:start position:0% +you stress the verb here the the beaver +I am + + align:start position:0% +I am + + + align:start position:0% +I am +listening I am + + align:start position:0% +listening I am + + + align:start position:0% +listening I am +listening so when would you say that + + align:start position:0% +listening so when would you say that + + + align:start position:0% +listening so when would you say that +what would you say I am listening did + + align:start position:0% +what would you say I am listening did + + + align:start position:0% +what would you say I am listening did +you listen to the music + + align:start position:0% +you listen to the music + + + align:start position:0% +you listen to the music +did you listen to the + + align:start position:0% +did you listen to the + + + align:start position:0% +did you listen to the +music I amist to + + align:start position:0% +music I amist to + + + align:start position:0% +music I amist to +now uh + + align:start position:0% +now uh + + + align:start position:0% +now uh +no + + align:start position:0% +no + + + align:start position:0% +no +ATT ATT talking + + align:start position:0% + + + + align:start position:0% + +something yes I am listening I am + + align:start position:0% +something yes I am listening I am + + + align:start position:0% +something yes I am listening I am +listening oh okay so if someone says pay + + align:start position:0% +listening oh okay so if someone says pay + + + align:start position:0% +listening oh okay so if someone says pay +attention listen to me pay attention + + align:start position:0% +attention listen to me pay attention + + + align:start position:0% +attention listen to me pay attention +listen to me why aren't you listening + + align:start position:0% +listen to me why aren't you listening + + + align:start position:0% +listen to me why aren't you listening +uhhuh what I am listening I am that's + + align:start position:0% +uhhuh what I am listening I am that's + + + align:start position:0% +uhhuh what I am listening I am that's +here it's a contrastive extra + + align:start position:0% +here it's a contrastive extra + + + align:start position:0% +here it's a contrastive extra +strong uh pitch stress hey T what are + + align:start position:0% +strong uh pitch stress hey T what are + + + align:start position:0% +strong uh pitch stress hey T what are +you doing why are you talking to this is + + align:start position:0% +you doing why are you talking to this is + + + align:start position:0% +you doing why are you talking to this is +time pay attention I am listening very + + align:start position:0% +time pay attention I am listening very + + + align:start position:0% +time pay attention I am listening very +good what I am listening and she's lying + + align:start position:0% +good what I am listening and she's lying + + + align:start position:0% +good what I am listening and she's lying +what do you what do you mean you are not + + align:start position:0% +what do you what do you mean you are not + + + align:start position:0% +what do you what do you mean you are not +listening okay what I am listening after + + align:start position:0% +listening okay what I am listening after + + + align:start position:0% +listening okay what I am listening after +ref me I am listening I am L I am + + align:start position:0% +ref me I am listening I am L I am + + + align:start position:0% +ref me I am listening I am L I am +listening I am okay your voice is extra + + align:start position:0% +listening I am okay your voice is extra + + + align:start position:0% +listening I am okay your voice is extra +high I am listening I am I am + + align:start position:0% +high I am listening I am I am + + + align:start position:0% +high I am listening I am I am +listening okay so if you put stress on + + align:start position:0% +listening okay so if you put stress on + + + align:start position:0% +listening okay so if you put stress on +the word I or am or listening they + + align:start position:0% +the word I or am or listening they + + + align:start position:0% +the word I or am or listening they +actually have very different meanings + + align:start position:0% +actually have very different meanings + + + align:start position:0% +actually have very different meanings +it's very important and PE the most + + align:start position:0% +it's very important and PE the most + + + align:start position:0% +it's very important and PE the most +common mistake is uh by non speakers + + align:start position:0% +common mistake is uh by non speakers + + + align:start position:0% +common mistake is uh by non speakers +they usually go up on up they go up on + + align:start position:0% +they usually go up on up they go up on + + + align:start position:0% +they usually go up on up they go up on +the first I'm listening most of the time + + align:start position:0% +the first I'm listening most of the time + + + align:start position:0% +the first I'm listening most of the time +that's not + + align:start position:0% + + + + align:start position:0% + +good okay now so in order to figure out + + align:start position:0% +good okay now so in order to figure out + + + align:start position:0% +good okay now so in order to figure out +which work gets which word is the most + + align:start position:0% +which work gets which word is the most + + + align:start position:0% +which work gets which word is the most +prominent element there are three uh + + align:start position:0% +prominent element there are three uh + + + align:start position:0% +prominent element there are three uh +three categories three things that you + + align:start position:0% +three categories three things that you + + + align:start position:0% +three categories three things that you +need to think about the first + + align:start position:0% + + + + align:start position:0% + +one usually new or important information + + align:start position:0% +one usually new or important information + + + align:start position:0% +one usually new or important information +and that and they usually + + align:start position:0% +and that and they usually + + + align:start position:0% +and that and they usually +come they are usually the last content + + align:start position:0% +come they are usually the last content + + + align:start position:0% +come they are usually the last content +word in the sentence new or important + + align:start position:0% +word in the sentence new or important + + + align:start position:0% +word in the sentence new or important +information okay that's why here last + + align:start position:0% +information okay that's why here last + + + align:start position:0% +information okay that's why here last +content word this what this word gets + + align:start position:0% +content word this what this word gets + + + align:start position:0% +content word this what this word gets +more stressed than can't I can't do it I + + align:start position:0% +more stressed than can't I can't do it I + + + align:start position:0% +more stressed than can't I can't do it I +can't do it there's more Str I can't do + + align:start position:0% +can't do it there's more Str I can't do + + + align:start position:0% +can't do it there's more Str I can't do +it okay so in a neutral phrase you want + + align:start position:0% +it okay so in a neutral phrase you want + + + align:start position:0% +it okay so in a neutral phrase you want +to stress you want to stress the last + + align:start position:0% +to stress you want to stress the last + + + align:start position:0% +to stress you want to stress the last +content word in a neutral phrase so + + align:start position:0% +content word in a neutral phrase so + + + align:start position:0% +content word in a neutral phrase so +which one gets which one is a prominent + + align:start position:0% +which one gets which one is a prominent + + + align:start position:0% +which one gets which one is a prominent +element + + align:start position:0% +element + + + align:start position:0% +element +here doing right so how do you say that + + align:start position:0% +here doing right so how do you say that + + + align:start position:0% +here doing right so how do you say that +what are you + + align:start position:0% +what are you + + + align:start position:0% +what are you +doing what are you one more + + align:start position:0% +doing what are you one more + + + align:start position:0% +doing what are you one more +time what are you doing what are you + + align:start position:0% +time what are you doing what are you + + + align:start position:0% +time what are you doing what are you +doing you this one + + align:start position:0% + + + + align:start position:0% + +next these are packaged for you you U is + + align:start position:0% +next these are packaged for you you U is + + + align:start position:0% +next these are packaged for you you U is +a Content word or a function word it's a + + align:start position:0% +a Content word or a function word it's a + + + align:start position:0% +a Content word or a function word it's a +function word + + align:start position:0% + + + + align:start position:0% + +right so where where where is the where + + align:start position:0% +right so where where where is the where + + + align:start position:0% +right so where where where is the where +is the prominence here package pack + + align:start position:0% +is the prominence here package pack + + + align:start position:0% +is the prominence here package pack +here's a package for you there's a + + align:start position:0% +here's a package for you there's a + + + align:start position:0% +here's a package for you there's a +package for you right if you + + align:start position:0% + + + + align:start position:0% + +say if you say here's a package for you + + align:start position:0% +say if you say here's a package for you + + + align:start position:0% +say if you say here's a package for you +oh here's a package for you too for you + + align:start position:0% +oh here's a package for you too for you + + + align:start position:0% +oh here's a package for you too for you +for you okay for you for me for you okay + + align:start position:0% +for you okay for you for me for you okay + + + align:start position:0% +for you okay for you for me for you okay +so you don't want to say here's a + + align:start position:0% +so you don't want to say here's a + + + align:start position:0% +so you don't want to say here's a +package for you that's weird there's a + + align:start position:0% +package for you that's weird there's a + + + align:start position:0% +package for you that's weird there's a +package for you there's a package for + + align:start position:0% +package for you there's a package for + + + align:start position:0% +package for you there's a package for +you what + + align:start position:0% + + + + align:start position:0% + +to's too there's too much too much + + align:start position:0% +to's too there's too much too much + + + align:start position:0% +to's too there's too much too much +traffic there's too much + + align:start position:0% +traffic there's too much + + + align:start position:0% +traffic there's too much +traffic okay there's too much traffic + + align:start position:0% +traffic okay there's too much traffic + + + align:start position:0% +traffic okay there's too much traffic +this + + align:start position:0% + + + + align:start position:0% + +one + + align:start position:0% + + + + align:start position:0% + +huh okay flap think think think about + + align:start position:0% +huh okay flap think think think about + + + align:start position:0% +huh okay flap think think think about +the + + align:start position:0% +the + + + align:start position:0% +the +flap he doesn't he he doesn't he doesn't + + align:start position:0% +flap he doesn't he he doesn't he doesn't + + + align:start position:0% +flap he doesn't he he doesn't he doesn't +he doesn't he doesn't understand her he + + align:start position:0% +he doesn't he doesn't understand her he + + + align:start position:0% +he doesn't he doesn't understand her he +does understand he doesn't understand + + align:start position:0% +does understand he doesn't understand + + + align:start position:0% +does understand he doesn't understand +her he does understand he doesn't + + align:start position:0% +her he does understand he doesn't + + + align:start position:0% +her he does understand he doesn't +understand her he does understand if he + + align:start position:0% +understand her he does understand if he + + + align:start position:0% +understand her he does understand if he +do not have a flat that it + + align:start position:0% +do not have a flat that it + + + align:start position:0% +do not have a flat that it +becomes he he doesn't he he doesn't + + align:start position:0% +becomes he he doesn't he he doesn't + + + align:start position:0% +becomes he he doesn't he he doesn't +understand he + + align:start position:0% +understand he + + + align:start position:0% +understand he +doesn't if you want to stress does then + + align:start position:0% +doesn't if you want to stress does then + + + align:start position:0% +doesn't if you want to stress does then +you will not have a flap he doesn't + + align:start position:0% +you will not have a flap he doesn't + + + align:start position:0% +you will not have a flap he doesn't +understand it he he no he doesn't + + align:start position:0% +understand it he he no he doesn't + + + align:start position:0% +understand it he he no he doesn't +understand it he doesn't okay so in a + + align:start position:0% +understand it he doesn't okay so in a + + + align:start position:0% +understand it he doesn't okay so in a +neutral place you want to have a flap he + + align:start position:0% +neutral place you want to have a flap he + + + align:start position:0% +neutral place you want to have a flap he +doesn't understander he does understand + + align:start position:0% +doesn't understander he does understand + + + align:start position:0% +doesn't understander he does understand +he doesn't understander he doesn't + + align:start position:0% +he doesn't understander he doesn't + + + align:start position:0% +he doesn't understander he doesn't +understand + + align:start position:0% +understand + + + align:start position:0% +understand +get rid of the H okay understander he + + align:start position:0% +get rid of the H okay understander he + + + align:start position:0% +get rid of the H okay understander he +doesn't + + align:start position:0% +doesn't + + + align:start position:0% +doesn't +understander this + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +one where record it record it for me + + align:start position:0% +one where record it record it for me + + + align:start position:0% +one where record it record it for me +record it for + + align:start position:0% + + + + align:start position:0% + +me okay now next emphatic stress and a + + align:start position:0% +me okay now next emphatic stress and a + + + align:start position:0% +me okay now next emphatic stress and a +particular element now let's say we have + + align:start position:0% +particular element now let's say we have + + + align:start position:0% +particular element now let's say we have +a regular + + align:start position:0% + + + + align:start position:0% + +and this is actually you would never say + + align:start position:0% +and this is actually you would never say + + + align:start position:0% +and this is actually you would never say +a sentence like this I may say his hair + + align:start position:0% +a sentence like this I may say his hair + + + align:start position:0% +a sentence like this I may say his hair +is blue his hair is blue okay then + + align:start position:0% +is blue his hair is blue okay then + + + align:start position:0% +is blue his hair is blue okay then +stress is here Matthew's hair is blue + + align:start position:0% +stress is here Matthew's hair is blue + + + align:start position:0% +stress is here Matthew's hair is blue +Matthew's hair is blue because this is + + align:start position:0% +Matthew's hair is blue because this is + + + align:start position:0% +Matthew's hair is blue because this is +the last cont his hair is blue his hair + + align:start position:0% +the last cont his hair is blue his hair + + + align:start position:0% +the last cont his hair is blue his hair +is blue Matthew's hair is blue okay + + align:start position:0% +is blue Matthew's hair is blue okay + + + align:start position:0% +is blue Matthew's hair is blue okay +Matthew's is blue but if say Matthew's + + align:start position:0% +Matthew's is blue but if say Matthew's + + + align:start position:0% +Matthew's is blue but if say Matthew's +hair is blue Matthew's hair is blue what + + align:start position:0% +hair is blue Matthew's hair is blue what + + + align:start position:0% +hair is blue Matthew's hair is blue what +does that + + align:start position:0% + + + + align:start position:0% + +mean no it's like yeah Matthew's here + + align:start position:0% +mean no it's like yeah Matthew's here + + + align:start position:0% +mean no it's like yeah Matthew's here +not Isaiah's not Jos Matthew's here is + + align:start position:0% +not Isaiah's not Jos Matthew's here is + + + align:start position:0% +not Isaiah's not Jos Matthew's here is +blue this one Matthew Matthew's Paris + + align:start position:0% +blue this one Matthew Matthew's Paris + + + align:start position:0% +blue this one Matthew Matthew's Paris +Blue what is that mean his eyes not his + + align:start position:0% +Blue what is that mean his eyes not his + + + align:start position:0% +Blue what is that mean his eyes not his +eyes yes he has black eyes Matthew's my + + align:start position:0% +eyes yes he has black eyes Matthew's my + + + align:start position:0% +eyes yes he has black eyes Matthew's my +brother Matthew's hair is blue once he + + align:start position:0% +brother Matthew's hair is blue once he + + + align:start position:0% +brother Matthew's hair is blue once he +had he had blue hair and that was + + align:start position:0% +had he had blue hair and that was + + + align:start position:0% +had he had blue hair and that was +awesome that was AES awesome I really + + align:start position:0% +awesome that was AES awesome I really + + + align:start position:0% +awesome that was AES awesome I really +wanted to have blue + + align:start position:0% +wanted to have blue + + + align:start position:0% +wanted to have blue +hair but + + align:start position:0% +hair but + + + align:start position:0% +hair but +no + + align:start position:0% + + + + align:start position:0% + +he Matthew's hair is blue what does that + + align:start position:0% + + + + align:start position:0% + +mean no that usually no still + + align:start position:0% + + + + align:start position:0% + +blue Matthew's hair is blue no it's the + + align:start position:0% +blue Matthew's hair is blue no it's the + + + align:start position:0% +blue Matthew's hair is blue no it's the +same thing I am I am listening if + + align:start position:0% +same thing I am I am listening if + + + align:start position:0% +same thing I am I am listening if +someone goes he say hey hey did you see + + align:start position:0% +someone goes he say hey hey did you see + + + align:start position:0% +someone goes he say hey hey did you see +that me is blue what it's black what it + + align:start position:0% +that me is blue what it's black what it + + + align:start position:0% +that me is blue what it's black what it +is blue mat it is blue it is blue it is + + align:start position:0% +is blue mat it is blue it is blue it is + + + align:start position:0% +is blue mat it is blue it is blue it is +blue okay when you put stress and the + + align:start position:0% +blue okay when you put stress and the + + + align:start position:0% +blue okay when you put stress and the +verb you're + + align:start position:0% +verb you're + + + align:start position:0% +verb you're +actually + + align:start position:0% +actually + + + align:start position:0% +actually +uh + + align:start position:0% +uh + + + align:start position:0% +uh +re uh you are actually denying what the + + align:start position:0% +re uh you are actually denying what the + + + align:start position:0% +re uh you are actually denying what the +other person has said and you are + + align:start position:0% +other person has said and you are + + + align:start position:0% +other person has said and you are +asserting + + align:start position:0% +asserting + + + align:start position:0% +asserting +uh yourself yes I am correct Matthew's + + align:start position:0% +uh yourself yes I am correct Matthew's + + + align:start position:0% +uh yourself yes I am correct Matthew's +hair is blue Matthew's hair is blue + + align:start position:0% +hair is blue Matthew's hair is blue + + + align:start position:0% +hair is blue Matthew's hair is blue +okay between pation and no no right now + + align:start position:0% +okay between pation and no no right now + + + align:start position:0% +okay between pation and no no right now +right now someone said I said did you + + align:start position:0% +right now someone said I said did you + + + align:start position:0% +right now someone said I said did you +see that did you see Matthew's hair it's + + align:start position:0% +see that did you see Matthew's hair it's + + + align:start position:0% +see that did you see Matthew's hair it's +blue it's blue and you you + + align:start position:0% + + + + align:start position:0% + +say so I mean that then that would be a + + align:start position:0% +say so I mean that then that would be a + + + align:start position:0% +say so I mean that then that would be a +a state statement against something like + + align:start position:0% +a state statement against something like + + + align:start position:0% +a state statement against something like +Matthew's Matthew's hair was black no it + + align:start position:0% +Matthew's Matthew's hair was black no it + + + align:start position:0% +Matthew's Matthew's hair was black no it +was + + align:start position:0% +was + + + align:start position:0% +was +blue is it's not comparing past tense + + align:start position:0% +blue is it's not comparing past tense + + + align:start position:0% +blue is it's not comparing past tense +past and F past and present it's not + + align:start position:0% +past and F past and present it's not + + + align:start position:0% +past and F past and present it's not +comparing past and present + + align:start position:0% +comparing past and present + + + align:start position:0% +comparing past and present +okay this + + align:start position:0% + + + + align:start position:0% + +one Matthew there's + + align:start position:0% +one Matthew there's + + + align:start position:0% +one Matthew there's +blue blue emphatic blue then what does + + align:start position:0% +blue blue emphatic blue then what does + + + align:start position:0% +blue blue emphatic blue then what does +that + + align:start position:0% + + + + align:start position:0% + +mean weird why is it blue I mean blue + + align:start position:0% +mean weird why is it blue I mean blue + + + align:start position:0% +mean weird why is it blue I mean blue +can you believe that + + align:start position:0% + + + + align:start position:0% + +blue what was it thinking + + align:start position:0% + + + + align:start position:0% + +blue okay uh let's hurry up now + + align:start position:0% +blue okay uh let's hurry up now + + + align:start position:0% +blue okay uh let's hurry up now +contrastive stress uh here if you're is + + align:start position:0% +contrastive stress uh here if you're is + + + align:start position:0% +contrastive stress uh here if you're is +it high or low is it a high or low class + + align:start position:0% +it high or low is it a high or low class + + + align:start position:0% +it high or low is it a high or low class +high or low so you stress both high and + + align:start position:0% +high or low so you stress both high and + + + align:start position:0% +high or low so you stress both high and +low high or low high or low okay so then + + align:start position:0% +low high or low high or low okay so then + + + align:start position:0% +low high or low high or low okay so then +uh the answer is high intermediate High + + align:start position:0% +uh the answer is high intermediate High + + + align:start position:0% +uh the answer is high intermediate High +intermediate not high intermediate but + + align:start position:0% +intermediate not high intermediate but + + + align:start position:0% +intermediate not high intermediate but +High + + align:start position:0% +High + + + align:start position:0% +High +intermediate + + align:start position:0% +intermediate + + + align:start position:0% +intermediate +okay and it can it can occur across two + + align:start position:0% +okay and it can it can occur across two + + + align:start position:0% +okay and it can it can occur across two +speakers is this is this the low + + align:start position:0% +speakers is this is this the low + + + align:start position:0% +speakers is this is this the low +intermediate English class and no it's + + align:start position:0% +intermediate English class and no it's + + + align:start position:0% +intermediate English class and no it's +the high intermediate High intermediate + + align:start position:0% +the high intermediate High intermediate + + + align:start position:0% +the high intermediate High intermediate +class + + align:start position:0% +class + + + align:start position:0% +class +right okay Circle the words that receive + + align:start position:0% +right okay Circle the words that receive + + + align:start position:0% +right okay Circle the words that receive +the most + + align:start position:0% +the most + + + align:start position:0% +the most +stress this + + align:start position:0% +stress this + + + align:start position:0% +stress this +one how are you how are you how are you + + align:start position:0% +one how are you how are you how are you + + + align:start position:0% +one how are you how are you how are you +but nowadays people many people say how + + align:start position:0% +but nowadays people many people say how + + + align:start position:0% +but nowadays people many people say how +hey how are you how are you right people + + align:start position:0% +hey how are you how are you right people + + + align:start position:0% +hey how are you how are you right people +say how are you they do that but + + align:start position:0% +say how are you they do that but + + + align:start position:0% +say how are you they do that but +according to the book you have to say + + align:start position:0% +according to the book you have to say + + + align:start position:0% +according to the book you have to say +how are you how are you and pretty + + align:start position:0% +how are you how are you and pretty + + + align:start position:0% +how are you how are you and pretty +good then you say how are you how are + + align:start position:0% +good then you say how are you how are + + + align:start position:0% +good then you say how are you how are +you how are you how are you right how + + align:start position:0% +you how are you how are you right how + + + align:start position:0% +you how are you how are you right how +are you this one + + align:start position:0% + + + + align:start position:0% + +okay uh uh what did you think of the + + align:start position:0% +okay uh uh what did you think of the + + + align:start position:0% +okay uh uh what did you think of the +movie what did you think of the movie + + align:start position:0% +movie what did you think of the movie + + + align:start position:0% +movie what did you think of the movie +what did you think of the movie so we + + align:start position:0% +what did you think of the movie so we + + + align:start position:0% +what did you think of the movie so we +say what here what did you what did you + + align:start position:0% +say what here what did you what did you + + + align:start position:0% +say what here what did you what did you +what did you think of the movie what did + + align:start position:0% +what did you think of the movie what did + + + align:start position:0% +what did you think of the movie what did +you think of the movie no get here of + + align:start position:0% +you think of the movie no get here of + + + align:start position:0% +you think of the movie no get here of +the whenever you have of the get rid of + + align:start position:0% +the whenever you have of the get rid of + + + align:start position:0% +the whenever you have of the get rid of +the V of the say of the especially in + + align:start position:0% +the V of the say of the especially in + + + align:start position:0% +the V of the say of the especially in +casual conversation what did you think + + align:start position:0% +casual conversation what did you think + + + align:start position:0% +casual conversation what did you think +of the think of the what did you think + + align:start position:0% +of the think of the what did you think + + + align:start position:0% +of the think of the what did you think +of the movie what you think of the movie + + align:start position:0% + + + + align:start position:0% + +think the + + align:start position:0% +think the + + + align:start position:0% +think the +here it was really you could say it was + + align:start position:0% +here it was really you could say it was + + + align:start position:0% +here it was really you could say it was +really good or it was really if you want + + align:start position:0% +really good or it was really if you want + + + align:start position:0% +really good or it was really if you want +to emphasize really it was really good + + align:start position:0% +to emphasize really it was really good + + + align:start position:0% +to emphasize really it was really good +right it was really + + align:start position:0% + + + + align:start position:0% + +good what did you think what did you + + align:start position:0% +good what did you think what did you + + + align:start position:0% +good what did you think what did you +think + + align:start position:0% +think + + + align:start position:0% +think +why you think what did you think what + + align:start position:0% +why you think what did you think what + + + align:start position:0% +why you think what did you think what +did you think okay so here you can + + align:start position:0% +did you think okay so here you can + + + align:start position:0% +did you think okay so here you can +emphasize these adverbs like uh man + + align:start position:0% +emphasize these adverbs like uh man + + + align:start position:0% +emphasize these adverbs like uh man +Isaiah's class is so boring I'm never + + align:start position:0% +Isaiah's class is so boring I'm never + + + align:start position:0% +Isaiah's class is so boring I'm never +taking Isaiah's class I'm never taking + + align:start position:0% +taking Isaiah's class I'm never taking + + + align:start position:0% +taking Isaiah's class I'm never taking +Isaiah's class or you could say I really + + align:start position:0% +Isaiah's class or you could say I really + + + align:start position:0% +Isaiah's class or you could say I really +like Isaiah's class right okay so let's + + align:start position:0% +like Isaiah's class right okay so let's + + + align:start position:0% +like Isaiah's class right okay so let's +practice something that you might say to + + align:start position:0% +practice something that you might say to + + + align:start position:0% +practice something that you might say to +your friends okay chances are you're + + align:start position:0% +your friends okay chances are you're + + + align:start position:0% +your friends okay chances are you're +going to say the ladder okay I really + + align:start position:0% +going to say the ladder okay I really + + + align:start position:0% +going to say the ladder okay I really +like Isaiah's + + align:start position:0% +like Isaiah's + + + align:start position:0% +like Isaiah's +class I really like IDE + + align:start position:0% +class I really like IDE + + + align:start position:0% +class I really like IDE +class okay here telephone rings and you + + align:start position:0% +class okay here telephone rings and you + + + align:start position:0% +class okay here telephone rings and you +say I'll get it I'll get it just I'll + + align:start position:0% +say I'll get it I'll get it just I'll + + + align:start position:0% +say I'll get it I'll get it just I'll +get it well I'll get it well I'll I'll + + align:start position:0% +get it well I'll get it well I'll I'll + + + align:start position:0% +get it well I'll get it well I'll I'll +get it I'll get + + align:start position:0% +get it I'll get + + + align:start position:0% +get it I'll get +it I'll get + + align:start position:0% +it I'll get + + + align:start position:0% +it I'll get +it uh I'll get it I'll get it I'll get + + align:start position:0% + + + + align:start position:0% + +it no I'll you see I'll get it I'll get + + align:start position:0% +it no I'll you see I'll get it I'll get + + + align:start position:0% +it no I'll you see I'll get it I'll get +it right and no I'll get it no no I'll + + align:start position:0% +it right and no I'll get it no no I'll + + + align:start position:0% +it right and no I'll get it no no I'll +get it + + align:start position:0% +get it + + + align:start position:0% +get it +you I'll get it + + align:start position:0% +you I'll get it + + + align:start position:0% +you I'll get it +right you go to you go to supermarket + + align:start position:0% +right you go to you go to supermarket + + + align:start position:0% +right you go to you go to supermarket +and the cashier uh Rings you up and you + + align:start position:0% +and the cashier uh Rings you up and you + + + align:start position:0% +and the cashier uh Rings you up and you +say oh she says thank you and you you go + + align:start position:0% +say oh she says thank you and you you go + + + align:start position:0% +say oh she says thank you and you you go +thank you thank you thank you thank you + + align:start position:0% +thank you thank you thank you thank you + + + align:start position:0% +thank you thank you thank you thank you +thank you + + align:start position:0% +thank you + + + align:start position:0% +thank you +okay + + align:start position:0% +okay + + + align:start position:0% +okay +huh say it + + align:start position:0% +huh say it + + + align:start position:0% +huh say it +again right she or he says you that + + align:start position:0% +again right she or he says you that + + + align:start position:0% +again right she or he says you that +happens to you some sometimes they say + + align:start position:0% +happens to you some sometimes they say + + + align:start position:0% +happens to you some sometimes they say +thank you yes then no no no no thank + + align:start position:0% +thank you yes then no no no no thank + + + align:start position:0% +thank you yes then no no no no thank +you okay you say thank + + align:start position:0% + + + + align:start position:0% + +youo no no no thank you wor just thank + + align:start position:0% +youo no no no thank you wor just thank + + + align:start position:0% +youo no no no thank you wor just thank +you yeah yeah yeah so that's actually + + align:start position:0% +you yeah yeah yeah so that's actually + + + align:start position:0% +you yeah yeah yeah so that's actually +strange yes they they they should say + + align:start position:0% +strange yes they they they should say + + + align:start position:0% +strange yes they they they should say +thank you and then you say thank you + + align:start position:0% +thank you and then you say thank you + + + align:start position:0% +thank you and then you say thank you +thank you if say thank you oh no no no + + align:start position:0% +thank you if say thank you oh no no no + + + align:start position:0% +thank you if say thank you oh no no no +no no thank you you okay you could do + + align:start position:0% +no no thank you you okay you could do + + + align:start position:0% +no no thank you you okay you could do +that you could here this + + align:start position:0% + + + + align:start position:0% + +one that was the movie + + align:start position:0% + + + + align:start position:0% + +right okay you could say it was too long + + align:start position:0% +right okay you could say it was too long + + + align:start position:0% +right okay you could say it was too long +or it was too long you can say either + + align:start position:0% + + + + align:start position:0% + +here was it a long + + align:start position:0% +here was it a long + + + align:start position:0% +here was it a long +drive you would go up on long because I + + align:start position:0% +drive you would go up on long because I + + + align:start position:0% +drive you would go up on long because I +guess uh what did you how did you get + + align:start position:0% +guess uh what did you how did you get + + + align:start position:0% +guess uh what did you how did you get +there I drove oh was it a long Drive + + align:start position:0% +there I drove oh was it a long Drive + + + align:start position:0% +there I drove oh was it a long Drive +drove is already old information so was + + align:start position:0% +drove is already old information so was + + + align:start position:0% +drove is already old information so was +it a long + + align:start position:0% + + + + align:start position:0% + +drive it was too long this one you have + + align:start position:0% +drive it was too long this one you have + + + align:start position:0% +drive it was too long this one you have +to go up on two okay because long this + + align:start position:0% +to go up on two okay because long this + + + align:start position:0% +to go up on two okay because long this +is old + + align:start position:0% +is old + + + align:start position:0% +is old +information okay you want to put + + align:start position:0% +information okay you want to put + + + align:start position:0% +information okay you want to put +prominence on the U new information not + + align:start position:0% +prominence on the U new information not + + + align:start position:0% +prominence on the U new information not +old information so here you have to say + + align:start position:0% +old information so here you have to say + + + align:start position:0% +old information so here you have to say +it was too long but here you can it was + + align:start position:0% +it was too long but here you can it was + + + align:start position:0% +it was too long but here you can it was +too long how was the movie oh it was too + + align:start position:0% +too long how was the movie oh it was too + + + align:start position:0% +too long how was the movie oh it was too +long how was the movie it was was too + + align:start position:0% +long how was the movie it was was too + + + align:start position:0% +long how was the movie it was was too +long hey how was it a long drive yeah it + + align:start position:0% +long hey how was it a long drive yeah it + + + align:start position:0% +long hey how was it a long drive yeah it +was too + + align:start position:0% +was too + + + align:start position:0% +was too +long + + align:start position:0% +long + + + align:start position:0% +long +okay + + align:start position:0% +okay + + + align:start position:0% +okay +okay uh we'll do this next Time Unreal + + align:start position:0% +okay uh we'll do this next Time Unreal + + + align:start position:0% +okay uh we'll do this next Time Unreal +past conditional \ No newline at end of file diff --git a/VUgN-YEklTU.txt b/VUgN-YEklTU.txt new file mode 100644 index 0000000000000000000000000000000000000000..c53ca0066a23f43a7ff0ef21b7bca9998ffc1341 --- /dev/null +++ b/VUgN-YEklTU.txt @@ -0,0 +1,422 @@ +Hi. + +In this problem, we're going +to look at random incidence + +under Erlang arrivals. + +First, let's parse +what that means. + +In a Poisson process, remember, +the time between + +arrivals, or the inter-arrival +time, is distributed as an + +exponential random variable. + +And random incidence for a +Poisson process refers to the + +somewhat surprising result +that when you consider a + +specific time, say, T-star, +then the length of the + +inter-arrival interval that +contains that time T-star is + +not distributed as an +exponential random variable. + +It's actually distributed as an +Erlang random variable of + +order 2 or it's distributed as +a sum of two exponential + +random variables. + +And the reason for +that is that it + +comprises of two parts. + +One is the time since the last +arrival until T-star, which is + +exponentially distributed, and +the time from T-star until the + +next arrival, which is also +exponentially distributed. + +So that brings us to a review +of what Erlang random + +variables are. + +An Erlang random variable of +order k is just the sum of k + +independent and identically +distributed + +exponential random variables. + +So to be more specific, if Ti +is an exponential random + +variable with parameter lambda, +then if you take kiid + +copies of Ti and add them up, +and call that Yk, then Yk is + +an Erlang random variable +of order k. + +And one other fact is that the +mean of Yk, the mean of an + +Erlang random variable of order +k, is just k, the order, + +over lambda, which is the rate +of the underlying exponential + +random variables. + +So as a consequence, if you have +an Erlang random variable + +of order two and that random +variable also has a mean of + +two over lambda, we can +interpret that random variable + +as just being the sum of two +exponential random variables. + +2 iid exponential random +variables, T1 and T2, where + +each one takes exponential +with the rate in lambda. + +OK, so in this problem now, +we're dealing with the random + +incidence not under Poisson +processes, but under something + +else, which we call here an +Erlang process with Erlang + +arrival times. + +So to be more specific, what +we're saying is that, instead + +of inter-arrival time being +exponentially distributed, in + +this process, and inter-arrival +time is actually + +distributed as an Erlang random +variable of order 2 + +with mean 2 over lambda. + +So to be explicit, this is no +longer a Poisson process. + +It's some other process because +the inter-arrival + +times are not exponential. + +So let's make use of this fact +that we talked about earlier + +because now we know that the +inter-arrival times of this + +Erlang process are +Erlang order 2 + +with mean 2 over lambda. + +But we know that that can just +be re-interpreted as a sum of + +two simple exponentials, each +with parameter lambda. + +So let's just draw another +picture and imagine that for + +each of these arrivals, so say +we have three sample arrivals + +in this Erlang process, we can +fill in, kind of, the gaps + +between these with additional +arrivals. + +And then think of each one of +these times as all being + +exponential with parameter +lambda. + +So this is a valid +interpretation because when we + +connect these, these +inter-arrival times correspond + +to the combination of two +inter-arrival times, which we + +know we can split that into +just two exponentials. + +So each one of these is an +exponential random variable. + +And when you combine them, you +get an Erlang order of 2. + +But the nice thing about this +is that if we look at this + +diagram, it actually is just +exactly a Poisson process with + +a rate lambda because +now, what we're + +dealing with are exactly-- + +the inter-arrival times +are now exactly + +exponential random variables. + +And so this is in fact, now, +just a simple Poisson process. + +And we can also just think of +it as we take the Poisson + +process, and take every other +arrival, say, all the + +even-numbered arrivals, and make +those corresponds to be + +arrivals in the Erlang +process. + +OK, so now let's think about +some specific time T-star. + +We want to know what is the +distribution of the length of + +this to be specific +inter-arrival interval that + +T-star is in. + +Well, what we can do is take it +down to the level of this + +Poisson process and look +at it from there. + +Well, we do that because, for +a Poisson process, we know + +about random incidence for +Poisson processes. + +And we know how to deal with +Poisson processes. + +So let's think about this now. + +Well, T-star is here. + +And what we know from random +incidence for a Poisson + +processes is that the length of +this inter-arrival interval + +for the Poisson process, +we know that this is an + +exponential plus +an exponential. + +So combined, this is +Erlang order 2. + + + +But that only covers +from here to here. + +And what we want is actually +from here to there. + +Well now, we tack on an extra +exponential because we know + +that the inter-arrival times-- + +the time between this arrival +and that arrival in the + +Poisson process is just +another exponential. + +And now all of these are in +[INAUDIBLE] time intervals. + +And they're all independent. + +And so the time of this +inter-arrival interval in the + +Erlang process is just going +to be the sum of three + +independent exponentials +within the + +underlying Poisson process. + +And so to answer here is +actually, it's going to be an + +Erlang of order 3. + + + +Now this is one possible +scenario for + +how this might occur. + +Another scenario is actually +that T-star is somewhere else. + +So let's draw this again. + + + +And suppose now, in this case, +T-star landed between an even + +numbered arrival in the Poisson +process and an odd + +numbered arrival. + +Now it could also arrive between +an odd numbered and an + +even numbered arrival. + +So it could be that T-star +is actually here. + +Well, but in this case, it's +actually more or less the same + +thing because now what we want +is the length of this entire + +inter-arrival interval, which, +in the Poisson world, we can + +break it down into random +incidence within this + +interval, this inter-arrival +interval, which is two + +exponentials, or an Erlang of +2, plus this interval, which + +is just a standard inter-arrival +time, which is + +another exponential. + +So in this case as well, we +have the sum of three + +independent exponential +random variables. + +And so, in either case, we have +that the inter-arrival + +time in the Erlang process +is an Erlang of order 3. + +And so the final answer is, in +fact, that the inter-arrival + +for random incidence under these +Erlang-type arrivals is + +an Erlang of order 3. + +OK, so in this problem we looked +at the random incidence + +under a different type of an +arrival process, not Poisson, + +but with Erlang random +variables. + +But we used the insight that +Erlang really can be + +re-interpreted as the sum of +independent and identically + +distributed exponential +random variables. + +And exponential random variables +can be viewed as one + +way of interpreting and viewing +a Poisson process. + +And so by going through those +steps, we were able to use + +what we know about random +incidence under Poisson + +processes to help us solve +this problem of random + +incidence its Erlang arrivals. + +So I hope that was helpful. + +And I'll see you next time. \ No newline at end of file diff --git a/Vyf-lQjk0rY.txt b/Vyf-lQjk0rY.txt new file mode 100644 index 0000000000000000000000000000000000000000..3633350c1be420ccdb34f422fdfe738e90588a91 --- /dev/null +++ b/Vyf-lQjk0rY.txt @@ -0,0 +1,1740 @@ +PROFESSOR: All right, now for + +something completely different. + +Before beginning though, +I would like to raise a + +procedural question. + +It was my intent that quiz +number two, which is like a + +little more than a week away, +was going to be part symmetry + +and part tensors. + +I don't want to have your +fortunes based by weight of + +2:1 on symmetry theory as +opposed to properties. + +What I would suggest, and you +can express your opinion + +either way, is that we postpone +quiz number two by + +maybe as much as 10 days, so +that it can be half symmetry + +and half the introductory +discussion of tensors. + +And if that does not create a +conflict with some of your + +other classes, I would propose +that as a suggestion. + +If not, we can just have on the +quiz what we're going to + +cover of tensors in the +next couple days and + +have the rest symmetry. + +So what I am suggesting is the +quiz was scheduled for a week + +from November 8, which +is a Tuesday. + +What I would suggest is putting +that off to the 18th, + +and that will give us four +extra lectures-- + +six extra lectures-- on tensors +and we can make the + +quiz 50-50. + +AUDIENCE: What does that do +to quiz number three? + +PROFESSOR: Quiz number three +is going to stay in place + +because it's right at +the end of the term. + +AUDIENCE: What about the +subject in three? + +PROFESSOR: It will +be all tensors. + +It will be all tensors +and properties. + +And the third quiz is set up +for longer than you think. + +It's December 8, so it'll +be about three weeks. + +AUDIENCE: So everything +from here on? + +PROFESSOR: Yeah. + +Does that make sense? + +Or is somebody going to have a +big, traumatic responsibility + +at that point? + +AUDIENCE: I don't know, but I +think it would be probably be + +easiest for us not to +have it three days + +before close of exams. + +PROFESSOR: OK, OK, that's +what I wanted to hear. + +How about if we went just a +little bit further then and + +did it not on the-- + +when was the suggestion? + +The 18th. + +Let's say we did it on +Tuesday the 15th? + +Does that conflict +with anything? + +AUDIENCE: That's a little bit. + +AUDIENCE: We were doing +it on the 18th. + +AUDIENCE: Is that Friday? + +[INTERPOSING VOICES] + +PROFESSOR: I'm sorry, 18th. + +I said it would be 17th. + +Excuse me. + +AUDIENCE: That definitely would +be a little better. + +PROFESSOR: OK, let me allow you +to think about that, and + +that would be pushing it back +one week and maybe it'd be-- + +we'll see how much material +on tensors we cover. + +So let's table it for now but +let's say, tentatively, let's + +consider seriously moving +it to the 15th. + +OK? + +But you guys have final +say if there's a + +preference that you have. + +OK let's talk about properties +in first a general and rather + +philosophic way. + +When we discuss properties we +very commonly lump together a + +set of behaviors which have +some common phenomenology. + +So for example, we will talk +about mechanical properties. + +And that's a basket in which we +place many different sorts + +of behavior. + +We place things like fracture +toughness, yield strength, + +elastic constants, a whole +variety of things involving + +strength deformation +and so on. + +Or another thing we very often +lump together in a basket is + +something called electrical +properties. + +And we talk about electrical +conductivity, ionic + +conductivity, electronic +conductivity. + +We talk about dielectric +constants, we talk about + +permittivity and permeability, +magnetic properties-- + +a whole bunch of other classes +of behavior, which have some + +sort of root or description in +terms of electromagnetism. + +There are though a lot of +strange aspects to properties. + +There are some properties that +are determined for material + +which no longer exists +when you're through + +determining the property. + +You have a sample you want +to know what the + +yield strength is. + +So you put the gradually +increasing load on it until + +finally, POP, it breaks. + +And now you know what the +yield strength is for a + +material that no +longer exists. + +Another example is an old one. + +Back before the days of X-ray +diffraction when people would + +try to characterize material, +anything that is very + +intensely colored usually looks +black, and that's not a + +very definitive property. + +The color of something is a very +prominent characteristic. + +So for mineralogists, in +particular, anybody going out + +into the hills and wanting to be +prepared to determine what + +a particular rock that they +tripped over was had something + +on a rope around their neck +called a streak plate. + +And what the streak plate +was was a little + +rectangle of porcelain. + +And they would take this black +mineral and rub it on this + +piece of porcelain and it +would leave a mark-- + +that was called the streak. + +And what this was was actually +little bunch of fragments that + +rubbed off on to the porcelain +because the porcelain was + +white and the fragments +were very small. + +A black piece of rock could +give you a streak that was + +brown or green or deep orange. + +And so you really were +determining the color of the + +material when it was in a form +finely divided enough that + +light could pass through it. + +So the streak test was a very +important diagnostic for + +determining minerals. + +There are some properties +that we refer to + +as structure sensitive. + +In the sense that +their value-- + +conductivity is a +good example-- + +the value of ionic conductivity +depends on the + +impurities and point +defects that are + +present in the material. + +So to say that the ionic +conductivity of a certain + +material is such and such, you +have to specify the purity and + +perfection of the material or +the property's meaningless. + +There are some properties that +are not even single-valued. + +And the best example there are +dielectric or magnetic + +properties. + +If you plot the magnetization +of a material, the magnetic + +moment per unit volume as a +function of the applied + +magnetic field B, the material +is initially non-magnetized. + +When you apply B, you get a +magnetic moment per unit + +volume that eventually +saturates. + +And then if you remove the +magnetic field, the material + +keeps some of its +magnetization. + +It doesn't go to zero when you +reduce the field to zero. + +You have to reverse the field +to get the property to go to + +zero and then magnetize it +in another direction. + +And if you continue to cycle the +magnetic field, you get a + +behavior like this. + +This is hysteresis, and this +type of behavior is called + +generally hysteretic. + +Same thing would be a relation +between the displacement + +vector and an applied +electric field. + +But clearly you can have any +value of the magnetization in + +this range. + +And if you relate the +magnetization as a function of + +the applied field, you can +get any value of the + +proportionality constant you +like between a negative + +maximum and a positive maximum +including zero. + +So there's a property that's +not even single-valued. + +Depends on the past history +of the sample. + +And then there are even more +peculiar properties. + +There are properties +that are-- + +we call them composite +properties and very often + +qualitative. + +What do they mean by a +composite property. + +Let me give you one example-- + +The property fuzzy. + +If I say fuzzy, you know +exactly what I mean. + +It means something that has +a diffuse reflectivity, + +something that has a surface +texture that's yielding. + +It's not like rubbing +a wire brush. + +It's soft and giving, a whole +collection of different + +properties. + +But yet when I say fuzzy, you +know exactly what I mean. + +Let me not be so facetious +as talking + +about a fuzzy property. + +People such as ceramists or +powder metallurgists very + +often will take a powder of a +material and consolidate it by + +compacting it and heating it, +very often subject to a + +compacting stress. + +And when you do that little +necks grow between the + +particles and they +hold together and + +the material is centric. + +So you refer to a property of +a powder as being centerable + +or the centerability +of a powder. + +You know exactly what somebody +means by that. + +But what does it depend on? + +It depends on the surface +energy, it depends on vapor + +pressure, depends on bulk +diffusion coefficients. + +It depends on surface diffusion +coefficients. + +And all of these things have to +be just right to make the + +powder something that easily +densifies upon heating in the + +application or not +of pressure. + +So you know exactly what I mean +by centerability, but it + +is a very complex property. + +And was one that really was not +understood until probably + +the late 1950s. + +Until then, it was an art that +was entirely empirical. + +And it was somebody here at +MIT, a fellow named Robert + +Coble, who developed a theory +of centering that was the + +first really workable theory +that described densification + +by heating and compaction. + +OK, composite property that +depends on many different + +individual properties +of the material. + +OK, what we are going to examine +here are equilibrium + +properties that can be +rigorously defined and + +measurable. + +So we're going to leave out of +the picture things like fuzzy + +and centerability. + +And let me give a very nice, +obscure definition of what I + +mean by a property. + +And what I mean by a property, +in terms of a formal + +statement, is the response of +a material to a specific + +change in a given set +of conditions. + +So the response of the material +to a specific change + +in a set of conditions that +relates independent properties + +and dependent properties for +a particular process. + +So I'll state that again +because I think + +it's terribly elegant. + +So a property is the response of +the material to a specific + +change in a given set of +conditions that relates + +independent and dependent +quantities in + +a particular process. + +Now there are a lot of +properties that have their + +roots solidly embedded +in thermodynamics. + +So let me give you +a few of those. + +What we'll talk about when +we specify a property is + +something that we will refer +to as a displacement. + +We'll talk about a generalized +displacement in response to a + +generalized force. + +So some of the thermodynamic +quantities that are related in + +this fashion-- + +if we list some forces and some +displacements, the thing + +that happens as a result of that +stimulus that's applied + +to the material. + +Temperature can be regarded as +a force that results in all + +sorts of processes +as a result-- + +thermal energy flow, +thermal expansion, + +all sorts of things. + +But one of the things that will +happen in response to a + +temperature change + +thermodynamically is an entropy. + +So you can view entropy as a +generalized displacement + +resulting from the application +of temperature as a + +generalized force. + +Another example is electric +field and the thing that + +happens there, and +electromagnetism, is the + +quantity, D, which +is displacement. + +Still another example, stress, +and the result of applying a + +stress, among other things, +is a strain. + +What is special about these +forces in this displacement is + +that their product is, in each +of these cases, energy, the + +change in internal energy +of the particular body. + +And when that is the case, +these are said to be + +conjugate-- + +a conjugate force and +displacement. + +And there are other examples +that one can come up .with. + +Now to talk about a specific +set of properties. + +Very often, and this crept into +the earlier discussion, + +very often the thing that we +do to a material, as a + +generalized force, +is a vector. + +So very often the thing that we +do to the material, apply + +an electric field, apply a +magnetic field, apply a + +temperature gradient, apply a +tensile stress, it has the + +characteristics of a vector, +magnitude and direction. + +And in many cases, the thing +that happens as a generalized + +displacement, we may call +this in general, + +q, is also a vector. + +An example is if we apply +an electric field as a + +generalized force, one thing +that might happen is a current + +flow, which is also a vector. + +And we are accustomed to +writing, q, the generalized + +displacement, as a +proportionality constant, + +sigma, which is in the case of +electric field and current + +flow, the electrical +conductivity. + +Let me call it, in general +terms, proportionality + +constant, a, times the +applied vector, p. + +Is this something we would +like to stick with as a + +general relation? + +Well let me submit that writing +an expression of this + +form makes an inherent +assumption. + +Namely that this will be true +for small, and we'll have to + +define for each property +what we mean by a + +small, applied vector. + +Let me give you an example. + +If p were-- + +the applied vector was electric +field, and the + +resulting vector was current +flow, and the relation between + +those is the conductivity-- + +a relation of this sort says +that if you double the field, + +you double the conductivity. + +You triple the field, you +triple the conductivity. + +Obviously this can't go on +indefinitely because all a + +sudden, POW, dielectric +breakdown. + +The sample evaporates +at the smoke. + +And again, you have the property +of a material which + +no longer exists. + +So a lot of properties, we +inherently assume that the + +applied vector is small in order +to write something in an + +expression of this form. + +So for conductivity, dielectric +breakdown is going + +to destroy the nice linear +relation between current flow + +and electric field. + +That's not always the case. + +Let me give you an example +of another property. + +And this is a property, magnetic +susceptibility, which + +relates the magnetization, which +is magnetic moment per + +unit volume, and relates that to +an applied electric field-- + +an applied magnetic field, H. +And the proportionality + +constant, represented by a Greek +chi, is the magnetic + +susceptibility. + +So let me give you a +specific example. + +Suppose we have a chunk of glass +and the glass contains a + +dilute concentration of iron. + +And iron carries a permanent +magnetic moment. + +And the reason I want to make +it a dilute concentration of + +iron is I don't want these +magnetic moments close enough + +that they can interact +with one another. + +I want this to, therefore, +be a dilute system. + +So we have different +iron atoms in this. + +Each iron atom has a +magnetic moment. + +And then we put this in a +magnetic field, H. And the + +magnetic field acts on each of +these little magnetic moments + +just as though it were +a compass needle. + +And so it will try to take each +of these moments and drag + +it into coincidence with +the magnetic field. + +But at a finite temperature, +temperatures making these + +magnetic moments jiggle +around, so at a finite + +temperature, the magnetic +moments will just not simply + +zing into coincidence with +the magnetic field. + +You'll have to increase +the magnetic + +field to make it larger. + +When that happens, more and more +of the magnetic moments + +will come into alignment. + +And if you put on a really +strong magnetic field, then + +every single magnetic moment +will be dragged into exact + +alignment with the magnetic +field and + +the system has saturated. + +There's no way you could squeeze +further magnetic + +moment per unit volume +out of it. + +So again, you would expect, for +this particular property, + +magnetic susceptibility of a +material, if you plot it as a + +function of the applied +magnetic field-- + +linear maybe be at low +applied fields-- + +but eventually if you make the +field strong enough, the + +system is going to saturate. + +And then again, no longer will +the direction of the + +magnetization, and that magnetic +moment, be parallel + +to H. But the property becomes +nonlinear if the applied + +vector is strong enough. + +This is an example of a property +where you would not + +go wrong at all by stating +direct proportionality. + +For ordering to occur, +temperature and applied field + +go hand in hand. + +Increased temperature tends +to create more disorder. + +Increased magnetic field tends +to align the moments. + +In the days when MIT had a +national magnet laboratory, + +the magnet laboratory held the +record for the strongest + +magnetic field ever produced +artificially by man. + +And if you took that magnetic +field and applied it to this + +system of dilute iron in a +glass, you would have to lower + +the temperature of the sample +to about 3 Kelvin before you + +would begin to see saturation. + +So even the strongest field that +you could produce in a + +laboratory environment would +not succeed in producing + +non-linearity until you cooled +the sample down almost to + +absolute zero. + +So here would be a case where +under any practical + +consideration whatsoever, +assumption of strict + +proportionality would be +right on the money. + +You'd be absolutely correct. + +But there's another assumption +built into this statement. + +P, the generalized force, is +a vector in the cases we're + +discussing now, and q +is also a vector. + +So when we write an expression +of this form you're making + +another assumption. + +And that is that the vector +displacement that results is + +always exactly parallel to the +vector that you apply. + +Do I make a big deal +out of this? + +Isn't that always going +to be the case? + +I mean whoever heard of taking +a piece of metal and putting + +an electric field on it in this +direction and having the + +current run off in +this direction. + +It's absurd. + +Or maybe it isn't so absurd. + +So let's think of some of the +atomistics of this process. + +Now, since I know I'm among +friends, I will not hesitate + +to display my ignorance, total + +ignorance, of polymer chemistry. + +So suppose we had a +piece of polymer. + +That's what a polymer +molecule looks like. + +It's a more or less linear +molecule, and so these might, + +in a very highly ordered +polymer, be chains that lined + +up like this. + +And suppose we now put an +electric field on this polymer + +and asked how the current +will flow. + +Again, it would not be absurd +to say that an electron + +sitting on this polymer chain +in response to this field + +would be constrained only to +flow in the direction of the + +chain and would find it rather +difficult to hop from one + +chain to another. + +So maybe, just maybe, we could +apply an electric field to a + +polymer and it would have a flow +in this direction, that + +would be pointing in this +direction, and the current + +flow, J, would be in +that direction. + +So should we maybe rethink this +idea of the direction of + +the generalized displacement +being not parallel to the + +direction of the generalized +force. + +OK, these are hypothetical +examples. + +Let me now give you an example +of a real property for a real + +material, for which the thing +that happens, the vector that + +happens, is decidedly not +parallel to the direction of + +the applied vector. + +OK, thermal conductivity is +something that relates a heat + +flux, usually represented by the +symbol K, and relates that + +to a temperature gradient, +dt dx, which is a vector. + +The thing that gives rise to +thermal conductivity can be + +either propagation of radiation +as in propagation of + +light traveling through a +transparent material. + +But the other mechanism for +thermal conductivity is modes + +of lattice vibration. + +When a material is hot, the +atoms are jiggling around and + +you can make the displacement +of an individual atom be + +represented by a sum of waves +moving in all different + +directions with a variety of +wavelengths in a variety of + +amplitudes. + +Take all those waves, add them +together at a particular time, + +and you get the displacement +of the atom. + +Propagation of heat by this +mechanism, by modes of thermal + +vibration, can be very, very +anisotropic and probably the + +best example of this is-- + +get a single crystal +of graphite. + +And have the layers, the +graphite sheets, which are + +hexagonal rings in which each +carbon has three neighbors, + +and have the sheets be parallel +to the surface of an + +extended two-dimensional slab. + +Now we can't do that. + +Single crystals of graphite +don't occur + +in sizes like that. + +But what you can do is make a +material called pyrolytic + +graphite that you make by having +a reaction in the vapor + +phase and having the soot that's +formed settle down onto + +a substrate. + +And what happens is you nucleate +a graphite crystal in + +one orientation, and that grows +preferentially with its + +layers parallel to the surface +on which it's nucleated. + +And these nuclei occur +at random. + +So you get a bunch of single +crystals of graphite, which + +all have their layers, their +three coordinated layers at + +parallel, but they +are oriented at + +random about their c-axis. + +And that's a material that's +very easy to prepare. + +And it's called pyrolytic +graphite, and it has + +interesting applications +and properties. + +OK, now I'm going to suggest an +experiment to you and I'll + +caution you, please do +not try this at home. + +Get yourself a piece of +pyrolytic graphite. + +Put a Bunsen burner +underneath it. + +Play the Bunsen burner on the +bottom of the sheet of + +pyrolytic graphite. + +And to determine temperature, +we'll take a ball of cotton + +and put it directly +above the flame. + +And then take another ball of +cotton and put it down at the + +end of the sheet. + +If you do that and bring up the +Bunsen burner, this piece + +of cotton will sit there +and sit there and sit + +there and sit there. + +And this piece of cotton will +instantly burst into flame. + +So here's a case where dt dx, +the thermal gradient, points + +in this direction. + +And the heat flow goes off in a +direction at right angles to + +the temperature gradient, +almost + +exactly at right angles. + +It turns out that the thermal +conductivity in this + +direction, the value +of K in the-- + +I want to put crystallographic +directions on this. + +But K parallel to the layers +is equal to 10 to the third + +times K, perpendicular +to the layers. + +So there's an anisotropy of the +property that amounts to a + +factor of 1,000. + +Very dramatic. + +So what I'm leading up is that +in a general relation between + +a generalized displacement, p, +and a generalized force-- + +I'm sorry, I'm using +q-- p and q-- + +we just can't simply put +some constant in front. + +Because that assumes inherently +that the direction + +of what happens, the vector +that happens, is exactly + +parallel to the direction of +the applied vector and that + +generally is not true. + +The difference may be small but +it has to be taken into + +consideration. + +All right, let me now suggest +a way of patching this up. + +What I'm going to +do is assume-- + +and it is an assumption-- + +we're going to assume that each +component of the vector + +that happens is given by-- + +in fancy terms, the vector +that results as the + +generalized displacement is +given by a linear combination + +of every component of the +vector that's applied. + +And that's what we've defined +as the generalized force. + +So how would we express +this analytically? + +I am going to use as my +coordinate system, not x, y, + +and z as we usually do, +I'm going to call + +it x1, x2, and x3. + +The reason is we'll see some +unique properties of these + +indices that are very useful +algebraically. + +So I'm going to now take my +applied vector, p, and I'm + +going to assume that it has +three components, p1, p2, and + +p3 along x1, x2, x3, +respectively. + +My coordinate system, although I +did not state it explicitly, + +is going to be a Cartesian +coordinate system, not a + +crystallographic coordinate +system. + +So what I'm proposing here is +that we take each component of + +the resulting vector q-- + +let's say q1-- + +and we'll assume that that's +given by a linear combination + +of all three components +of the vector p. + +So it'll be some number times +p1 plus some number times p2 + +plus some number times p3. + +And those numbers in general +will be different. + +So let's say I call the +coefficient a, and now I'm + +going to define a convention +that will stay with us. + +I'm going to define each of +these coefficients, a, in + +terms of the index of the +component of the generalized + +displacement which is being +computed, and the coefficient + +modifies the component of the +generalized force for that + +particular term. + +So I'm going to call this a11, +where the 1 goes with this and + +the 1 goes with this. + +I'm going to call this a12, so +that the 1 again says it's a + +contribution to q1. + +The 2 says that this +term modifies p2. . + +And this similarly +would be a13. + +For the term component of the +generalized displacement, q2, + +I'll use the coefficients a21 +times p1 plus a22 times p2, + +plus 23 times p3. + +And q3 similarly will be a31 +times p1, plus a32 times p2 + +plus a33 times p3. + +So I've got three simultaneous +equations then, one for each + +component of the vector that +results, the generalized + +displacement. + +So I can sum up this set of +three equations by saying that + +the i-th component of q, where +this is some particular + +component, q1, q2, or q3, is +given by the sum over j from 1 + +to 3 of aij times p sub j. + +So I've got ai1 times p1, ai2 +times p2 plus ai3 times p3. + +So this is in a nice, compact +little nugget the expression + +that we are assuming will +apply for all sorts of + +physical properties in which +this is a vector + +and this is a vector-- + +electrical conductivity, +magnetic susceptibility, + +thermal conductivity, +and so on. + +OK, this is a bad point to +introduce something as hairy + +as what comes next. + +But I've got one minute left, +and I think I can do it. + +I'm going to introduce something +called the Einstein + +convention after old Albert +Einstein himself. + +I'm sorry, but nobody +said everything this + +term had to be easy. + +So let me introduce, if you're +ready for it, the Einstein + +convention. + +Old Albert, I think, was just +as lazy as anybody else. + +And he said it is going to be +a bloody pain in the butt-- + +I don't know if he put +it exactly this way. + +It's going to be a pain in the +butt to write this summation + +every time we want to combine +three terms in a linear + +combination. + +So the Einstein convention is +let us throw out the sigma and + +write this expression just +as qi times aij p sub j. + +And whenever we see a subscript +repeated, summation + +over repeated subscript +is implied. + +OK so that's the Einstein +convention. + +It will save us the trouble +of writing in a lot + +of summation signs. + +But I would caution you that +this convention, compact and + +convenient as it is, can define +some polynomials that + +are nightmares. + +So let me give you one example +of this, and this is actually + +a physical property. + +Let me say that Cijkl is given +by ai capital I aj capital J + +ak capital K, al capital L times +let's say D, capital I, + +capital J, capital K, capital +L. That actually, believe it + +or not, means something +physically and we're going to + +get to that in due course. + +But what this is, taking the +Einstein convention into + +account, this is a quadruple +summation over capital I, + +capital J, capital K, and +capital L. These are very + +often referred to in this +business as dummy indices, + +meaning that they don't really +mean anything physically. + +They're just indices +of summation. + +I would caution you that +this is a term + +that does not permute. + +If I say those are dummy +indices, it means one thing. + +If I say those are indices, +dummy, it means something + +completely different, and +you're apt to get + +a poke in the nose. + +OK so these are dummy indices. + +Now, what does this represent? + +I won't say what it represents +physically, but this consists + +of terms in four variables +times a coefficient. + +So there are five quantities +in each term. + +If I sum over capital I, J, and +K from 1 to 3, there are + +going to be 81 such terms, +each with five + +elements in each term. + +So it's going to be on the order +of 405 terms in this + +summation, and we've collapsed +the whole thing down, 405 + +terms in this nice summation. + +So it is a great facility for +writing down expressions + +explicitly, but these terms can +hide a terribly, terribly + +complex polynomial. + +All right, I think that's +a good place to quit. + +It continues to amaze me, +though, how some absolutely + +trivial convention, when first +proposed by a great man, will + +carry that man's name no matter +how stupid it is. + +So this is called the Einstein +convention by everybody who + +works in this field. + +Another one, just briefly to +finish up, when you discuss + +dislocations, you talk about a +circuit of steps around the + +dislocation. + +That's called a Burgers +circuit. + +And if you do the same circuit +in a corresponding piece of + +material that doesn't have a +dislocation, if this circuit + +closes, this circuit fails to +close by something that's + +called the Burgers vector. + +Every book on dislocation theory +says, Shockley called + +this good material. + +I'm sorry, Shockley called +this good material, and + +Shockley called this +bad material. + +Big deal-- + +good material, bad material +because it's got a + +dislocation in it. + +But that is identified with +Shockley's name in every + +discussion of dislocation. + +I'm just jealous because nobody +has ever said according + +to me, such and such is-- + +all right, see you +later in the week + +for more great things. \ No newline at end of file diff --git a/W5zVgQ4SbX8.txt b/W5zVgQ4SbX8.txt new file mode 100644 index 0000000000000000000000000000000000000000..a4f4ae99287c6a9b8546bebf204b20ada5163d30 --- /dev/null +++ b/W5zVgQ4SbX8.txt @@ -0,0 +1,1171 @@ +align:start position:0% + +to predict the outcomes of the Supreme + + align:start position:0% +to predict the outcomes of the Supreme + + + align:start position:0% +to predict the outcomes of the Supreme +Court Martin used cases from 1994 + + align:start position:0% +Court Martin used cases from 1994 + + + align:start position:0% +Court Martin used cases from 1994 +through 2001 he chose this period of + + align:start position:0% +through 2001 he chose this period of + + + align:start position:0% +through 2001 he chose this period of +time because the Supreme Court was + + align:start position:0% +time because the Supreme Court was + + + align:start position:0% +time because the Supreme Court was +composed of the same nine justices that + + align:start position:0% +composed of the same nine justices that + + + align:start position:0% +composed of the same nine justices that +were justices when he made his + + align:start position:0% +were justices when he made his + + + align:start position:0% +were justices when he made his +predictions in 2002 these nine justices + + align:start position:0% +predictions in 2002 these nine justices + + + align:start position:0% +predictions in 2002 these nine justices +were Breyer Ginsburg Kennedy O'Connor + + align:start position:0% +were Breyer Ginsburg Kennedy O'Connor + + + align:start position:0% +were Breyer Ginsburg Kennedy O'Connor +Rehnquist who was the Chief Justice + + align:start position:0% +Rehnquist who was the Chief Justice + + + align:start position:0% +Rehnquist who was the Chief Justice +Scalia Souter Stevens and Thomas this + + align:start position:0% +Scalia Souter Stevens and Thomas this + + + align:start position:0% +Scalia Souter Stevens and Thomas this +was a very rare dataset since as I + + align:start position:0% +was a very rare dataset since as I + + + align:start position:0% +was a very rare dataset since as I +mentioned earlier this was the longest + + align:start position:0% +mentioned earlier this was the longest + + + align:start position:0% +mentioned earlier this was the longest +period of time with the same set of + + align:start position:0% +period of time with the same set of + + + align:start position:0% +period of time with the same set of +justices in over a hundred and eighty + + align:start position:0% +justices in over a hundred and eighty + + + align:start position:0% +justices in over a hundred and eighty +years + + align:start position:0% +years + + + align:start position:0% +years +this allowed Martin to use a larger + + align:start position:0% +this allowed Martin to use a larger + + + align:start position:0% +this allowed Martin to use a larger +dataset that might have been available + + align:start position:0% +dataset that might have been available + + + align:start position:0% +dataset that might have been available +if he was doing this experiment at a + + align:start position:0% +if he was doing this experiment at a + + + align:start position:0% +if he was doing this experiment at a +different time in this lecture will + + align:start position:0% +different time in this lecture will + + + align:start position:0% +different time in this lecture will +focus on predicting justice Stevens + + align:start position:0% +focus on predicting justice Stevens + + + align:start position:0% +focus on predicting justice Stevens +decisions he is generally considered a + + align:start position:0% +decisions he is generally considered a + + + align:start position:0% +decisions he is generally considered a +justice who started out moderate but + + align:start position:0% +justice who started out moderate but + + + align:start position:0% +justice who started out moderate but +became more liberal during his time on + + align:start position:0% +became more liberal during his time on + + + align:start position:0% +became more liberal during his time on +the Supreme Court although he is a + + align:start position:0% +the Supreme Court although he is a + + + align:start position:0% +the Supreme Court although he is a +self-proclaimed conservative in this + + align:start position:0% +self-proclaimed conservative in this + + + align:start position:0% +self-proclaimed conservative in this +problem our dependent variable is + + align:start position:0% +problem our dependent variable is + + + align:start position:0% +problem our dependent variable is +whether or not justice Stevens voted to + + align:start position:0% +whether or not justice Stevens voted to + + + align:start position:0% +whether or not justice Stevens voted to +reverse the lower court decision this is + + align:start position:0% +reverse the lower court decision this is + + + align:start position:0% +reverse the lower court decision this is +a binary variable taking value one if + + align:start position:0% +a binary variable taking value one if + + + align:start position:0% +a binary variable taking value one if +justice Stevens decided to reverse or + + align:start position:0% +justice Stevens decided to reverse or + + + align:start position:0% +justice Stevens decided to reverse or +overturn the lower court decision and + + align:start position:0% +overturn the lower court decision and + + + align:start position:0% +overturn the lower court decision and +taking value zero if justice Stevens + + align:start position:0% +taking value zero if justice Stevens + + + align:start position:0% +taking value zero if justice Stevens +voted to affirm or maintain the lower + + align:start position:0% +voted to affirm or maintain the lower + + + align:start position:0% +voted to affirm or maintain the lower +court decision our independent variables + + align:start position:0% +court decision our independent variables + + + align:start position:0% +court decision our independent variables +are six different properties of the case + + align:start position:0% +are six different properties of the case + + + align:start position:0% +are six different properties of the case +the circuit court of origin or is the + + align:start position:0% +the circuit court of origin or is the + + + align:start position:0% +the circuit court of origin or is the +circuit or lower court where the case + + align:start position:0% +circuit or lower court where the case + + + align:start position:0% +circuit or lower court where the case +came from there are 13 different circuit + + align:start position:0% +came from there are 13 different circuit + + + align:start position:0% +came from there are 13 different circuit +courts in the United States the 1st + + align:start position:0% +courts in the United States the 1st + + + align:start position:0% +courts in the United States the 1st +through 11th and Washington DC courts + + align:start position:0% +through 11th and Washington DC courts + + + align:start position:0% +through 11th and Washington DC courts +are defined by region and the federal + + align:start position:0% +are defined by region and the federal + + + align:start position:0% +are defined by region and the federal +court is defined by the subject matter + + align:start position:0% +court is defined by the subject matter + + + align:start position:0% +court is defined by the subject matter +of the case the issue area of the case + + align:start position:0% +of the case the issue area of the case + + + align:start position:0% +of the case the issue area of the case +gives each case a category like Civil + + align:start position:0% +gives each case a category like Civil + + + align:start position:0% +gives each case a category like Civil +Rights or federal taxation the type of + + align:start position:0% +Rights or federal taxation the type of + + + align:start position:0% +Rights or federal taxation the type of +petitioner and type of respondent + + align:start position:0% +petitioner and type of respondent + + + align:start position:0% +petitioner and type of respondent +defined to parties in the case some + + align:start position:0% +defined to parties in the case some + + + align:start position:0% +defined to parties in the case some +examples are the + + align:start position:0% +examples are the + + + align:start position:0% +examples are the +United States an employer or an employee + + align:start position:0% +United States an employer or an employee + + + align:start position:0% +United States an employer or an employee +the ideological direction of the lower + + align:start position:0% +the ideological direction of the lower + + + align:start position:0% +the ideological direction of the lower +court decision describes whether the + + align:start position:0% +court decision describes whether the + + + align:start position:0% +court decision describes whether the +lower court made what was considered a + + align:start position:0% +lower court made what was considered a + + + align:start position:0% +lower court made what was considered a +liberal or a conservative decision the + + align:start position:0% +liberal or a conservative decision the + + + align:start position:0% +liberal or a conservative decision the +last variable indicates whether or not + + align:start position:0% +last variable indicates whether or not + + + align:start position:0% +last variable indicates whether or not +the petitioner argued that a law or + + align:start position:0% +the petitioner argued that a law or + + + align:start position:0% +the petitioner argued that a law or +practice was unconstitutional to collect + + align:start position:0% +practice was unconstitutional to collect + + + align:start position:0% +practice was unconstitutional to collect +this data Martin and his colleagues read + + align:start position:0% +this data Martin and his colleagues read + + + align:start position:0% +this data Martin and his colleagues read +through all of the cases and coded the + + align:start position:0% +through all of the cases and coded the + + + align:start position:0% +through all of the cases and coded the +information some of it like the circuit + + align:start position:0% +information some of it like the circuit + + + align:start position:0% +information some of it like the circuit +court is straightforward but other + + align:start position:0% +court is straightforward but other + + + align:start position:0% +court is straightforward but other +information required a judgment call + + align:start position:0% +information required a judgment call + + + align:start position:0% +information required a judgment call +like the ideological direction of the + + align:start position:0% +like the ideological direction of the + + + align:start position:0% +like the ideological direction of the +lower court now that we have our data + + align:start position:0% +lower court now that we have our data + + + align:start position:0% +lower court now that we have our data +and variables we are ready to predict + + align:start position:0% +and variables we are ready to predict + + + align:start position:0% +and variables we are ready to predict +the decisions of Justice Stevens we can + + align:start position:0% +the decisions of Justice Stevens we can + + + align:start position:0% +the decisions of Justice Stevens we can +use logistic regression and we get a + + align:start position:0% +use logistic regression and we get a + + + align:start position:0% +use logistic regression and we get a +model where some of the most significant + + align:start position:0% +model where some of the most significant + + + align:start position:0% +model where some of the most significant +variables are whether or not the case is + + align:start position:0% +variables are whether or not the case is + + + align:start position:0% +variables are whether or not the case is +from the Second Circuit Court with a + + align:start position:0% +from the Second Circuit Court with a + + + align:start position:0% +from the Second Circuit Court with a +coefficient of one point six six whether + + align:start position:0% +coefficient of one point six six whether + + + align:start position:0% +coefficient of one point six six whether +or not the case is from the Fourth + + align:start position:0% +or not the case is from the Fourth + + + align:start position:0% +or not the case is from the Fourth +Circuit Court with a coefficient of two + + align:start position:0% +Circuit Court with a coefficient of two + + + align:start position:0% +Circuit Court with a coefficient of two +point eight two and whether or not the + + align:start position:0% +point eight two and whether or not the + + + align:start position:0% +point eight two and whether or not the +lower court decision was liberal with a + + align:start position:0% +lower court decision was liberal with a + + + align:start position:0% +lower court decision was liberal with a +coefficient of negative one point two + + align:start position:0% +coefficient of negative one point two + + + align:start position:0% +coefficient of negative one point two +two well this tells us that the case + + align:start position:0% +two well this tells us that the case + + + align:start position:0% +two well this tells us that the case +being from the second or fourth circuit + + align:start position:0% +being from the second or fourth circuit + + + align:start position:0% +being from the second or fourth circuit +courts is predictive of justice Stevens + + align:start position:0% +courts is predictive of justice Stevens + + + align:start position:0% +courts is predictive of justice Stevens +reversing the case and the lower court + + align:start position:0% +reversing the case and the lower court + + + align:start position:0% +reversing the case and the lower court +decision being liberal is predictive of + + align:start position:0% +decision being liberal is predictive of + + + align:start position:0% +decision being liberal is predictive of +justice Stevens affirming the case it's + + align:start position:0% +justice Stevens affirming the case it's + + + align:start position:0% +justice Stevens affirming the case it's +difficult to understand which factors + + align:start position:0% +difficult to understand which factors + + + align:start position:0% +difficult to understand which factors +are more important due to things like + + align:start position:0% +are more important due to things like + + + align:start position:0% +are more important due to things like +the scales of the variables and the + + align:start position:0% +the scales of the variables and the + + + align:start position:0% +the scales of the variables and the +possibility of multicollinearity it's + + align:start position:0% +possibility of multicollinearity it's + + + align:start position:0% +possibility of multicollinearity it's +also difficult to quickly evaluate what + + align:start position:0% +also difficult to quickly evaluate what + + + align:start position:0% +also difficult to quickly evaluate what +the prediction would be for a new case + + align:start position:0% +the prediction would be for a new case + + + align:start position:0% +the prediction would be for a new case +so instead of logistic regression Martin + + align:start position:0% +so instead of logistic regression Martin + + + align:start position:0% +so instead of logistic regression Martin +and his colleagues used a method called + + align:start position:0% +and his colleagues used a method called + + + align:start position:0% +and his colleagues used a method called +classification and regression trees or + + align:start position:0% +classification and regression trees or + + + align:start position:0% +classification and regression trees or +cart this method builds what is called a + + align:start position:0% +cart this method builds what is called a + + + align:start position:0% +cart this method builds what is called a +tree by splitting on the values of the + + align:start position:0% +tree by splitting on the values of the + + + align:start position:0% +tree by splitting on the values of the +independent variables to predict the + + align:start position:0% +independent variables to predict the + + + align:start position:0% +independent variables to predict the +outcome for a new observation or case + + align:start position:0% +outcome for a new observation or case + + + align:start position:0% +outcome for a new observation or case +you can follow the splits in the tree + + align:start position:0% +you can follow the splits in the tree + + + align:start position:0% +you can follow the splits in the tree +and at the end you predict the most + + align:start position:0% +and at the end you predict the most + + + align:start position:0% +and at the end you predict the most +frequent outcome in the training set + + align:start position:0% +frequent outcome in the training set + + + align:start position:0% +frequent outcome in the training set +that followed the same path + + align:start position:0% +that followed the same path + + + align:start position:0% +that followed the same path +advantages of cart are that it does not + + align:start position:0% +advantages of cart are that it does not + + + align:start position:0% +advantages of cart are that it does not +assume a linear model like logistic + + align:start position:0% +assume a linear model like logistic + + + align:start position:0% +assume a linear model like logistic +regression or linear regression and it's + + align:start position:0% +regression or linear regression and it's + + + align:start position:0% +regression or linear regression and it's +a very interpretable model let's look at + + align:start position:0% +a very interpretable model let's look at + + + align:start position:0% +a very interpretable model let's look at +an example this plot shows sample data + + align:start position:0% +an example this plot shows sample data + + + align:start position:0% +an example this plot shows sample data +for two independent variables x and y + + align:start position:0% +for two independent variables x and y + + + align:start position:0% +for two independent variables x and y +and each data point is colored by the + + align:start position:0% +and each data point is colored by the + + + align:start position:0% +and each data point is colored by the +outcome variable red or gray cart tries + + align:start position:0% +outcome variable red or gray cart tries + + + align:start position:0% +outcome variable red or gray cart tries +to split this data into subsets so that + + align:start position:0% +to split this data into subsets so that + + + align:start position:0% +to split this data into subsets so that +each subset is as pure or homogeneous as + + align:start position:0% +each subset is as pure or homogeneous as + + + align:start position:0% +each subset is as pure or homogeneous as +possible the first three splits that + + align:start position:0% +possible the first three splits that + + + align:start position:0% +possible the first three splits that +cart would create are shown here then + + align:start position:0% +cart would create are shown here then + + + align:start position:0% +cart would create are shown here then +the standard prediction made by a cart + + align:start position:0% +the standard prediction made by a cart + + + align:start position:0% +the standard prediction made by a cart +model is just the majority in each + + align:start position:0% +model is just the majority in each + + + align:start position:0% +model is just the majority in each +subset if a new observation fell into + + align:start position:0% +subset if a new observation fell into + + + align:start position:0% +subset if a new observation fell into +one of these two subsets then we would + + align:start position:0% +one of these two subsets then we would + + + align:start position:0% +one of these two subsets then we would +predict red since the majority of the + + align:start position:0% +predict red since the majority of the + + + align:start position:0% +predict red since the majority of the +observations in those subsets are red + + align:start position:0% +observations in those subsets are red + + + align:start position:0% +observations in those subsets are red +however if a new observation fell into + + align:start position:0% +however if a new observation fell into + + + align:start position:0% +however if a new observation fell into +one of these two subsets we would + + align:start position:0% +one of these two subsets we would + + + align:start position:0% +one of these two subsets we would +predict gray since the majority of the + + align:start position:0% +predict gray since the majority of the + + + align:start position:0% +predict gray since the majority of the +observations in those two subsets are + + align:start position:0% +observations in those two subsets are + + + align:start position:0% +observations in those two subsets are +gray a cart model is represented by what + + align:start position:0% +gray a cart model is represented by what + + + align:start position:0% +gray a cart model is represented by what +we call a tree the tree for the splits + + align:start position:0% +we call a tree the tree for the splits + + + align:start position:0% +we call a tree the tree for the splits +we just generated is shown on the right + + align:start position:0% +we just generated is shown on the right + + + align:start position:0% +we just generated is shown on the right +the first split tests whether the + + align:start position:0% +the first split tests whether the + + + align:start position:0% +the first split tests whether the +variable X is less than 60 if yes the + + align:start position:0% +variable X is less than 60 if yes the + + + align:start position:0% +variable X is less than 60 if yes the +model says to predict red and if no the + + align:start position:0% +model says to predict red and if no the + + + align:start position:0% +model says to predict red and if no the +model moves on to the next split then + + align:start position:0% +model moves on to the next split then + + + align:start position:0% +model moves on to the next split then +the second split checks whether or not + + align:start position:0% +the second split checks whether or not + + + align:start position:0% +the second split checks whether or not +the variable Y is less than 20 if no the + + align:start position:0% +the variable Y is less than 20 if no the + + + align:start position:0% +the variable Y is less than 20 if no the +model says to predict gray but if yes + + align:start position:0% +model says to predict gray but if yes + + + align:start position:0% +model says to predict gray but if yes +the model moves on to the next split the + + align:start position:0% +the model moves on to the next split the + + + align:start position:0% +the model moves on to the next split the +third splay checks whether or not the + + align:start position:0% +third splay checks whether or not the + + + align:start position:0% +third splay checks whether or not the +variable X is less than 85 if yes then + + align:start position:0% +variable X is less than 85 if yes then + + + align:start position:0% +variable X is less than 85 if yes then +the model says to predict red and if no + + align:start position:0% +the model says to predict red and if no + + + align:start position:0% +the model says to predict red and if no +the model says to predict gray there are + + align:start position:0% +the model says to predict gray there are + + + align:start position:0% +the model says to predict gray there are +a couple things to keep in mind when + + align:start position:0% +a couple things to keep in mind when + + + align:start position:0% +a couple things to keep in mind when +reading trees in this tree and for the + + align:start position:0% +reading trees in this tree and for the + + + align:start position:0% +reading trees in this tree and for the +trees we'll generate in our a yes + + align:start position:0% +trees we'll generate in our a yes + + + align:start position:0% +trees we'll generate in our a yes +response is always to the left and a no + + align:start position:0% +response is always to the left and a no + + + align:start position:0% +response is always to the left and a no +response is always to the right also + + align:start position:0% +response is always to the right also + + + align:start position:0% +response is always to the right also +make sure you always start at the top of + + align:start position:0% +make sure you always start at the top of + + + align:start position:0% +make sure you always start at the top of +the tree the X less than 85 split + + align:start position:0% +the tree the X less than 85 split + + + align:start position:0% +the tree the X less than 85 split +only counts for observations for which X + + align:start position:0% +only counts for observations for which X + + + align:start position:0% +only counts for observations for which X +is greater than 60 and y is less than 20 + + align:start position:0% +is greater than 60 and y is less than 20 + + + align:start position:0% +is greater than 60 and y is less than 20 +in the next video we'll discuss how cart + + align:start position:0% +in the next video we'll discuss how cart + + + align:start position:0% +in the next video we'll discuss how cart +decides how many splits to generate and + + align:start position:0% +decides how many splits to generate and + + + align:start position:0% +decides how many splits to generate and +how the final predictions are made \ No newline at end of file diff --git a/WFF2VR7syCE.txt b/WFF2VR7syCE.txt new file mode 100644 index 0000000000000000000000000000000000000000..d6105b8edbe2defe911131e35ad472936273657a --- /dev/null +++ b/WFF2VR7syCE.txt @@ -0,0 +1,13907 @@ +align:start position:0% + +okay so you remember in the last lecture + + align:start position:0% +okay so you remember in the last lecture + + + align:start position:0% +okay so you remember in the last lecture +we discussed a technique + + align:start position:0% + + + + align:start position:0% + +called and schen we were relying on the + + align:start position:0% +called and schen we were relying on the + + + align:start position:0% +called and schen we were relying on the +facts + + align:start position:0% +facts + + + align:start position:0% +facts +that plasma has refractive index + + align:start position:0% +that plasma has refractive index + + + align:start position:0% +that plasma has refractive index +gradients inside it uh which cause a + + align:start position:0% +gradients inside it uh which cause a + + + align:start position:0% +gradients inside it uh which cause a +deflection and that deflection angle of + + align:start position:0% +deflection and that deflection angle of + + + align:start position:0% +deflection and that deflection angle of +the uh Rays going through the plasma was + + align:start position:0% +the uh Rays going through the plasma was + + + align:start position:0% +the uh Rays going through the plasma was +going to be something like one over two + + align:start position:0% +going to be something like one over two + + + align:start position:0% +going to be something like one over two +times the critical density times the + + align:start position:0% +times the critical density times the + + + align:start position:0% +times the critical density times the +integral of the gradient of the electron + + align:start position:0% +integral of the gradient of the electron + + + align:start position:0% +integral of the gradient of the electron +density along the path of our probing B + + align:start position:0% +density along the path of our probing B + + + align:start position:0% +density along the path of our probing B +and what we did in schen is we filtered + + align:start position:0% +and what we did in schen is we filtered + + + align:start position:0% +and what we did in schen is we filtered +the Rays using a lens and a stop at the + + align:start position:0% +the Rays using a lens and a stop at the + + + align:start position:0% +the Rays using a lens and a stop at the +focal plane we're able to filter our + + align:start position:0% +focal plane we're able to filter our + + + align:start position:0% +focal plane we're able to filter our +Rays with certain angles we can let + + align:start position:0% +Rays with certain angles we can let + + + align:start position:0% +Rays with certain angles we can let +through undeflected Ray block undle + + align:start position:0% +through undeflected Ray block undle + + + align:start position:0% +through undeflected Ray block undle +Grays we could do it in isotropic + + align:start position:0% +Grays we could do it in isotropic + + + align:start position:0% +Grays we could do it in isotropic +fashion we could do it with a knife edge + + align:start position:0% +fashion we could do it with a knife edge + + + align:start position:0% +fashion we could do it with a knife edge +and this enabled us to image effectively + + align:start position:0% +and this enabled us to image effectively + + + align:start position:0% +and this enabled us to image effectively +the gradients in the electron density + + align:start position:0% +the gradients in the electron density + + + align:start position:0% +the gradients in the electron density +inside our plasma this is particularly + + align:start position:0% +inside our plasma this is particularly + + + align:start position:0% +inside our plasma this is particularly +useful if you got something with sharp + + align:start position:0% +useful if you got something with sharp + + + align:start position:0% +useful if you got something with sharp +density gradients such as + + align:start position:0% + + + + align:start position:0% + +shs but when we were doing this we + + align:start position:0% +shs but when we were doing this we + + + align:start position:0% +shs but when we were doing this we +actually made a pretty big assumption + + align:start position:0% +actually made a pretty big assumption + + + align:start position:0% +actually made a pretty big assumption +that I kind of buried here we + + align:start position:0% + + + + align:start position:0% + +assumed that we have know this placement + + align:start position:0% +assumed that we have know this placement + + + align:start position:0% +assumed that we have know this placement +of the ray that the Rays pick up some + + align:start position:0% +of the ray that the Rays pick up some + + + align:start position:0% +of the ray that the Rays pick up some +angle as they travel through our plasma + + align:start position:0% +angle as they travel through our plasma + + + align:start position:0% +angle as they travel through our plasma +so I'll draw a little plasma here we + + align:start position:0% +so I'll draw a little plasma here we + + + align:start position:0% +so I'll draw a little plasma here we +assume that the Rays picked up some sort + + align:start position:0% +assume that the Rays picked up some sort + + + align:start position:0% +assume that the Rays picked up some sort +of angle but they didn't themselves get + + align:start position:0% +of angle but they didn't themselves get + + + align:start position:0% +of angle but they didn't themselves get +displaced whereas for some realistic + + align:start position:0% +displaced whereas for some realistic + + + align:start position:0% +displaced whereas for some realistic +extended plasma they would be displaced + + align:start position:0% +extended plasma they would be displaced + + + align:start position:0% +extended plasma they would be displaced +inside the plasma as well as picking up + + align:start position:0% +inside the plasma as well as picking up + + + align:start position:0% +inside the plasma as well as picking up +some angle and so the Rays themselves + + align:start position:0% +some angle and so the Rays themselves + + + align:start position:0% +some angle and so the Rays themselves +would not only have an angle they would + + align:start position:0% +would not only have an angle they would + + + align:start position:0% +would not only have an angle they would +have some displacement and when we use + + align:start position:0% +have some displacement and when we use + + + align:start position:0% +have some displacement and when we use +our Imaging system with a lens the Rays + + align:start position:0% +our Imaging system with a lens the Rays + + + align:start position:0% +our Imaging system with a lens the Rays +should endend up somewhere else on our + + align:start position:0% +should endend up somewhere else on our + + + align:start position:0% +should endend up somewhere else on our +object plane not in the same place they + + align:start position:0% +object plane not in the same place they + + + align:start position:0% +object plane not in the same place they +started with buten we assume that there + + align:start position:0% +started with buten we assume that there + + + align:start position:0% +started with buten we assume that there +was no Ray + + align:start position:0% + + + + align:start position:0% + +displacement and this was actually + + align:start position:0% +displacement and this was actually + + + align:start position:0% +displacement and this was actually +equivalent to US assuming that our + + align:start position:0% +equivalent to US assuming that our + + + align:start position:0% +equivalent to US assuming that our +object was very very thin so if instead + + align:start position:0% +object was very very thin so if instead + + + align:start position:0% +object was very very thin so if instead +of having this extended object like this + + align:start position:0% +of having this extended object like this + + + align:start position:0% +of having this extended object like this +we have an object that's incredibly thin + + align:start position:0% +we have an object that's incredibly thin + + + align:start position:0% +we have an object that's incredibly thin +like that and you have rays of light + + align:start position:0% +like that and you have rays of light + + + align:start position:0% +like that and you have rays of light +coming in but then just get + + align:start position:0% +coming in but then just get + + + align:start position:0% +coming in but then just get +instantaneously deflected like that this + + align:start position:0% +instantaneously deflected like that this + + + align:start position:0% +instantaneously deflected like that this +works out okay because there's no sort + + align:start position:0% +works out okay because there's no sort + + + align:start position:0% +works out okay because there's no sort +of uh path along inside the plasma for + + align:start position:0% +of uh path along inside the plasma for + + + align:start position:0% +of uh path along inside the plasma for +these Rays uh to become displaced + + align:start position:0% +these Rays uh to become displaced + + + align:start position:0% +these Rays uh to become displaced +whereas they are in an extended object + + align:start position:0% +whereas they are in an extended object + + + align:start position:0% +whereas they are in an extended object +so we made this assumption but we're now + + align:start position:0% +so we made this assumption but we're now + + + align:start position:0% +so we made this assumption but we're now +going to relax that and have a look at + + align:start position:0% +going to relax that and have a look at + + + align:start position:0% +going to relax that and have a look at +what happens when we do true shog graphy + + align:start position:0% +what happens when we do true shog graphy + + + align:start position:0% +what happens when we do true shog graphy +which is where we're interested not just + + align:start position:0% +which is where we're interested not just + + + align:start position:0% +which is where we're interested not just +in the angles of the Rays but their + + align:start position:0% +in the angles of the Rays but their + + + align:start position:0% +in the angles of the Rays but their +displacements as well so I'm going to + + align:start position:0% +displacements as well so I'm going to + + + align:start position:0% +displacements as well so I'm going to +try and draw slightly better version of + + align:start position:0% +try and draw slightly better version of + + + align:start position:0% +try and draw slightly better version of +this image hopefully with some nice + + align:start position:0% +this image hopefully with some nice + + + align:start position:0% +this image hopefully with some nice +straight lines let's see how it goes + + align:start position:0% +straight lines let's see how it goes + + + align:start position:0% +straight lines let's see how it goes +here's my plasma + + align:start position:0% +here's my plasma + + + align:start position:0% +here's my plasma +again I'm going to have a + + align:start position:0% +again I'm going to have a + + + align:start position:0% +again I'm going to have a +lens here I'm going to set up my lens + + align:start position:0% +lens here I'm going to set up my lens + + + align:start position:0% +lens here I'm going to set up my lens +such that it brings into + + align:start position:0% +such that it brings into + + + align:start position:0% +such that it brings into +Focus Rays from this object + + align:start position:0% + + + + align:start position:0% + +plane onto some image plane back here + + align:start position:0% + + + + align:start position:0% + +and what I'm going to have is the + + align:start position:0% +and what I'm going to have is the + + + align:start position:0% +and what I'm going to have is the +undeflected Rays so imagine there was no + + align:start position:0% +undeflected Rays so imagine there was no + + + align:start position:0% +undeflected Rays so imagine there was no +plasma here the Rays would just go + + align:start position:0% +plasma here the Rays would just go + + + align:start position:0% +plasma here the Rays would just go +through + + align:start position:0% + + + + align:start position:0% + +here and they would all go through a + + align:start position:0% +here and they would all go through a + + + align:start position:0% +here and they would all go through a +focal point back + + align:start position:0% + + + + align:start position:0% + +here so this again looks like the setup + + align:start position:0% +here so this again looks like the setup + + + align:start position:0% +here so this again looks like the setup +we had for our schin but the difference + + align:start position:0% +we had for our schin but the difference + + + align:start position:0% +we had for our schin but the difference +is now if we consider the Rays being + + align:start position:0% +is now if we consider the Rays being + + + align:start position:0% +is now if we consider the Rays being +deflected inside the plasma they're + + align:start position:0% +deflected inside the plasma they're + + + align:start position:0% +deflected inside the plasma they're +going to pick up some sort of displac + + align:start position:0% +going to pick up some sort of displac + + + align:start position:0% +going to pick up some sort of displac +so for example this Ray is going to be + + align:start position:0% +so for example this Ray is going to be + + + align:start position:0% +so for example this Ray is going to be +displaced down like this this Ray maybe + + align:start position:0% +displaced down like this this Ray maybe + + + align:start position:0% +displaced down like this this Ray maybe +is also going to be displaced down with + + align:start position:0% +is also going to be displaced down with + + + align:start position:0% +is also going to be displaced down with +a little bit and this Ray is going to be + + align:start position:0% +a little bit and this Ray is going to be + + + align:start position:0% +a little bit and this Ray is going to be +this place upwards such that when they + + align:start position:0% +this place upwards such that when they + + + align:start position:0% +this place upwards such that when they +get to the object plane they now have + + align:start position:0% +get to the object plane they now have + + + align:start position:0% +get to the object plane they now have +some distance that they have been + + align:start position:0% +some distance that they have been + + + align:start position:0% +some distance that they have been +translated compared to the undeflected + + align:start position:0% +translated compared to the undeflected + + + align:start position:0% +translated compared to the undeflected +one and then all that a lens does is it + + align:start position:0% +one and then all that a lens does is it + + + align:start position:0% +one and then all that a lens does is it +puts light back on the image plane where + + align:start position:0% +puts light back on the image plane where + + + align:start position:0% +puts light back on the image plane where +it came from on the object plane with + + align:start position:0% +it came from on the object plane with + + + align:start position:0% +it came from on the object plane with +some inversion other things like that + + align:start position:0% +some inversion other things like that + + + align:start position:0% +some inversion other things like that +but that means because these Rays have + + align:start position:0% +but that means because these Rays have + + + align:start position:0% +but that means because these Rays have +actually been moved because the light + + align:start position:0% +actually been moved because the light + + + align:start position:0% +actually been moved because the light +has been moved around they're going to + + align:start position:0% +has been moved around they're going to + + + align:start position:0% +has been moved around they're going to +show up in different places on the image + + align:start position:0% +show up in different places on the image + + + align:start position:0% +show up in different places on the image +plane and this is why I really hope I + + align:start position:0% +plane and this is why I really hope I + + + align:start position:0% +plane and this is why I really hope I +can draw this properly because this is + + align:start position:0% +can draw this properly because this is + + + align:start position:0% +can draw this properly because this is +quite a complicated diagram so give me a + + align:start position:0% +quite a complicated diagram so give me a + + + align:start position:0% +quite a complicated diagram so give me a +moment to focus on + + align:start position:0% +moment to focus on + + + align:start position:0% +moment to focus on +it so let's start with this Ray here + + align:start position:0% +it so let's start with this Ray here + + + align:start position:0% +it so let's start with this Ray here +it's going to go down is going to go + + align:start position:0% +it's going to go down is going to go + + + align:start position:0% +it's going to go down is going to go +down below the focal point because it's + + align:start position:0% +down below the focal point because it's + + + align:start position:0% +down below the focal point because it's +been deflected downwards and so it's + + align:start position:0% +been deflected downwards and so it's + + + align:start position:0% +been deflected downwards and so it's +going to end + + align:start position:0% +going to end + + + align:start position:0% +going to end +up here so slightly above where the + + align:start position:0% +up here so slightly above where the + + + align:start position:0% +up here so slightly above where the +original Ray was going to go + + align:start position:0% +original Ray was going to go + + + align:start position:0% +original Ray was going to go +this Ray here is going to get deflected + + align:start position:0% +this Ray here is going to get deflected + + + align:start position:0% +this Ray here is going to get deflected +downwards and it's then the lens is + + align:start position:0% +downwards and it's then the lens is + + + align:start position:0% +downwards and it's then the lens is +going to push it up and it's also going + + align:start position:0% +going to push it up and it's also going + + + align:start position:0% +going to push it up and it's also going +to go + + align:start position:0% +to go + + + align:start position:0% +to go +below the focal point here as well but + + align:start position:0% +below the focal point here as well but + + + align:start position:0% +below the focal point here as well but +it's going to be deflected up from its + + align:start position:0% +it's going to be deflected up from its + + + align:start position:0% +it's going to be deflected up from its +original position and this one here is + + align:start position:0% +original position and this one here is + + + align:start position:0% +original position and this one here is +going to go + + align:start position:0% +going to go + + + align:start position:0% +going to go +up + + align:start position:0% +up + + + align:start position:0% +up +uh bend that one slightly oh no I didn't + + align:start position:0% +uh bend that one slightly oh no I didn't + + + align:start position:0% +uh bend that one slightly oh no I didn't +want it to goow I got it right the first + + align:start position:0% +want it to goow I got it right the first + + + align:start position:0% +want it to goow I got it right the first +time there we go and this one is + + align:start position:0% +time there we go and this one is + + + align:start position:0% +time there we go and this one is +deflected downwards because it was + + align:start position:0% +deflected downwards because it was + + + align:start position:0% +deflected downwards because it was +deflected up of the object here so what + + align:start position:0% +deflected up of the object here so what + + + align:start position:0% +deflected up of the object here so what +we are seeing is + + align:start position:0% +we are seeing is + + + align:start position:0% +we are seeing is +that this lens is now Imaging the light + + align:start position:0% +that this lens is now Imaging the light + + + align:start position:0% +that this lens is now Imaging the light +into slightly different places than we + + align:start position:0% +into slightly different places than we + + + align:start position:0% +into slightly different places than we +had before so we set a displacement of + + align:start position:0% +had before so we set a displacement of + + + align:start position:0% +had before so we set a displacement of +the + + align:start position:0% + + + + align:start position:0% + +Rays and you might want to think about + + align:start position:0% +Rays and you might want to think about + + + align:start position:0% +Rays and you might want to think about +displacement as an + + align:start position:0% +displacement as an + + + align:start position:0% +displacement as an +intensity modulation because of course + + align:start position:0% +intensity modulation because of course + + + align:start position:0% +intensity modulation because of course +there aren't just three Rays there are a + + align:start position:0% +there aren't just three Rays there are a + + + align:start position:0% +there aren't just three Rays there are a +large number of rays and these all make + + align:start position:0% +large number of rays and these all make + + + align:start position:0% +large number of rays and these all make +up an image and so initially maybe you + + align:start position:0% +up an image and so initially maybe you + + + align:start position:0% +up an image and so initially maybe you +had a nice uniform pattern these yellow + + align:start position:0% +had a nice uniform pattern these yellow + + + align:start position:0% +had a nice uniform pattern these yellow +Rays would have made a nice uniform + + align:start position:0% +Rays would have made a nice uniform + + + align:start position:0% +Rays would have made a nice uniform +circular beam like this and now your + + align:start position:0% +circular beam like this and now your + + + align:start position:0% +circular beam like this and now your +blue-rays are going to be + + align:start position:0% +blue-rays are going to be + + + align:start position:0% +blue-rays are going to be +distorted and there's going to be + + align:start position:0% +distorted and there's going to be + + + align:start position:0% +distorted and there's going to be +regions of very bright intensity and + + align:start position:0% +regions of very bright intensity and + + + align:start position:0% +regions of very bright intensity and +regions of lesser intensity and regions + + align:start position:0% +regions of lesser intensity and regions + + + align:start position:0% +regions of lesser intensity and regions +that are about the same so we'll have + + align:start position:0% +that are about the same so we'll have + + + align:start position:0% +that are about the same so we'll have +all sorts of interesting features inside + + align:start position:0% +all sorts of interesting features inside + + + align:start position:0% +all sorts of interesting features inside +this one way to think about this + + align:start position:0% +this one way to think about this + + + align:start position:0% +this one way to think about this +imagine we took our beam and now we're + + align:start position:0% +imagine we took our beam and now we're + + + align:start position:0% +imagine we took our beam and now we're +looking at the laser beam it's coming + + align:start position:0% +looking at the laser beam it's coming + + + align:start position:0% +looking at the laser beam it's coming +directly towards us through the plasma + + align:start position:0% +directly towards us through the plasma + + + align:start position:0% +directly towards us through the plasma +imagine we arranged it so we have nine + + align:start position:0% +imagine we arranged it so we have nine + + + align:start position:0% +imagine we arranged it so we have nine +little dots maybe we've got nine little + + align:start position:0% +little dots maybe we've got nine little + + + align:start position:0% +little dots maybe we've got nine little +laser pointers pointing through our + + align:start position:0% +laser pointers pointing through our + + + align:start position:0% +laser pointers pointing through our +plasma like + + align:start position:0% +plasma like + + + align:start position:0% +plasma like +this now as these Rays come through the + + align:start position:0% +this now as these Rays come through the + + + align:start position:0% +this now as these Rays come through the +plasma and they're deflected onto our + + align:start position:0% +plasma and they're deflected onto our + + + align:start position:0% +plasma and they're deflected onto our +camera here we would end up with the + + align:start position:0% +camera here we would end up with the + + + align:start position:0% +camera here we would end up with the +dots in different places so we could + + align:start position:0% +dots in different places so we could + + + align:start position:0% +dots in different places so we could +have this one is moved up here this one + + align:start position:0% +have this one is moved up here this one + + + align:start position:0% +have this one is moved up here this one +is moved like this + + align:start position:0% +is moved like this + + + align:start position:0% +is moved like this +this one is moved like this and so on + + align:start position:0% +this one is moved like this and so on + + + align:start position:0% +this one is moved like this and so on +and you can just think there's a series + + align:start position:0% +and you can just think there's a series + + + align:start position:0% +and you can just think there's a series +of displacements for these dots and if + + align:start position:0% +of displacements for these dots and if + + + align:start position:0% +of displacements for these dots and if +you're able to measure all these + + align:start position:0% +you're able to measure all these + + + align:start position:0% +you're able to measure all these +displacements perhaps you could work out + + align:start position:0% +displacements perhaps you could work out + + + align:start position:0% +displacements perhaps you could work out +something about the plasma itself and + + align:start position:0% +something about the plasma itself and + + + align:start position:0% +something about the plasma itself and +we'll talk a little bit about more + + align:start position:0% +we'll talk a little bit about more + + + align:start position:0% +we'll talk a little bit about more +quantitative measurements doing this but + + align:start position:0% +quantitative measurements doing this but + + + align:start position:0% +quantitative measurements doing this but +this is just qualitatively the picture + + align:start position:0% +this is just qualitatively the picture + + + align:start position:0% +this is just qualitatively the picture +here another way to think about this if + + align:start position:0% +here another way to think about this if + + + align:start position:0% +here another way to think about this if +you prefer these are just different + + align:start position:0% +you prefer these are just different + + + align:start position:0% +you prefer these are just different +conceptual ways of trying to think about + + align:start position:0% +conceptual ways of trying to think about + + + align:start position:0% +conceptual ways of trying to think about +the same thing imagine we initially put + + align:start position:0% +the same thing imagine we initially put + + + align:start position:0% +the same thing imagine we initially put +through the sort of tic tac toe grid of + + align:start position:0% +through the sort of tic tac toe grid of + + + align:start position:0% +through the sort of tic tac toe grid of +light here we've sort of blocked it off + + align:start position:0% +light here we've sort of blocked it off + + + align:start position:0% +light here we've sort of blocked it off +so we've got two vertical lines two + + align:start position:0% +so we've got two vertical lines two + + + align:start position:0% +so we've got two vertical lines two +horizontal lines these lines as they go + + align:start position:0% +horizontal lines these lines as they go + + + align:start position:0% +horizontal lines these lines as they go +through the plasma the light will be + + align:start position:0% +through the plasma the light will be + + + align:start position:0% +through the plasma the light will be +deflected by different amounts so for + + align:start position:0% +deflected by different amounts so for + + + align:start position:0% +deflected by different amounts so for +example this line here could be + + align:start position:0% +example this line here could be + + + align:start position:0% +example this line here could be +deflected like this this one could be + + align:start position:0% +deflected like this this one could be + + + align:start position:0% +deflected like this this one could be +deflected like this and so you sort of + + align:start position:0% +deflected like this and so you sort of + + + align:start position:0% +deflected like this and so you sort of +see we have some sort of + + align:start position:0% +see we have some sort of + + + align:start position:0% +see we have some sort of +distortion to the grid that we're + + align:start position:0% +distortion to the grid that we're + + + align:start position:0% +distortion to the grid that we're +getting out of this and our initial grid + + align:start position:0% +getting out of this and our initial grid + + + align:start position:0% +getting out of this and our initial grid +will these nice straight parallel lines + + align:start position:0% +will these nice straight parallel lines + + + align:start position:0% +will these nice straight parallel lines +is now a distorted grid instead and + + align:start position:0% +is now a distorted grid instead and + + + align:start position:0% +is now a distorted grid instead and +that's very important because chidog + + align:start position:0% +that's very important because chidog + + + align:start position:0% +that's very important because chidog +graphy do not actually uce an image I've + + align:start position:0% +graphy do not actually uce an image I've + + + align:start position:0% +graphy do not actually uce an image I've +called this the image plane here but we + + align:start position:0% +called this the image plane here but we + + + align:start position:0% +called this the image plane here but we +don't actually get an image out because + + align:start position:0% +don't actually get an image out because + + + align:start position:0% +don't actually get an image out because +we have something which is significantly + + align:start position:0% +we have something which is significantly + + + align:start position:0% +we have something which is significantly +distorted and it no longer reserves the + + align:start position:0% +distorted and it no longer reserves the + + + align:start position:0% +distorted and it no longer reserves the +things that we like to preserve in + + align:start position:0% +things that we like to preserve in + + + align:start position:0% +things that we like to preserve in +images we take a picture with a camera + + align:start position:0% +images we take a picture with a camera + + + align:start position:0% +images we take a picture with a camera +we like straight lines to remain + + align:start position:0% +we like straight lines to remain + + + align:start position:0% +we like straight lines to remain +straight here the straight lines do not + + align:start position:0% +straight here the straight lines do not + + + align:start position:0% +straight here the straight lines do not +remain straight they don't remain + + align:start position:0% +remain straight they don't remain + + + align:start position:0% +remain straight they don't remain +parallel we don't preserve length + + align:start position:0% +parallel we don't preserve length + + + align:start position:0% +parallel we don't preserve length +anything like that but there's still + + align:start position:0% +anything like that but there's still + + + align:start position:0% +anything like that but there's still +clearly information stored inside these + + align:start position:0% +clearly information stored inside these + + + align:start position:0% +clearly information stored inside these +images pictures uh that corresponds to + + align:start position:0% +images pictures uh that corresponds to + + + align:start position:0% +images pictures uh that corresponds to +the density inside the plasma and we'll + + align:start position:0% +the density inside the plasma and we'll + + + align:start position:0% +the density inside the plasma and we'll +talk a little bit more about how to do + + align:start position:0% +talk a little bit more about how to do + + + align:start position:0% +talk a little bit more about how to do +this quantitatively so any questions on + + align:start position:0% +this quantitatively so any questions on + + + align:start position:0% +this quantitatively so any questions on +this yeah the plasma here is acting like + + align:start position:0% +this yeah the plasma here is acting like + + + align:start position:0% +this yeah the plasma here is acting like +a what we need the second lens for + + align:start position:0% +a what we need the second lens for + + + align:start position:0% +a what we need the second lens for +absolutely great question yeah + + align:start position:0% +absolutely great question yeah + + + align:start position:0% +absolutely great question yeah +so I put the second lens in here for a + + align:start position:0% +so I put the second lens in here for a + + + align:start position:0% +so I put the second lens in here for a +couple of reasons first of all I find it + + align:start position:0% +couple of reasons first of all I find it + + + align:start position:0% +couple of reasons first of all I find it +conceptually simpler because you can see + + align:start position:0% +conceptually simpler because you can see + + + align:start position:0% +conceptually simpler because you can see +the deflection angles at the focal point + + align:start position:0% +the deflection angles at the focal point + + + align:start position:0% +the deflection angles at the focal point +here because when I read off the + + align:start position:0% +here because when I read off the + + + align:start position:0% +here because when I read off the +position of the Rays at this focal plane + + align:start position:0% +position of the Rays at this focal plane + + + align:start position:0% +position of the Rays at this focal plane +I can tell whether they've been + + align:start position:0% +I can tell whether they've been + + + align:start position:0% +I can tell whether they've been +deflected up or down which is slightly + + align:start position:0% +deflected up or down which is slightly + + + align:start position:0% +deflected up or down which is slightly +harder to do here you could Absol + + align:start position:0% +harder to do here you could Absol + + + align:start position:0% +harder to do here you could Absol +absolutely put your detector right here + + align:start position:0% +absolutely put your detector right here + + + align:start position:0% +absolutely put your detector right here +okay so you could put a bit of film or + + align:start position:0% +okay so you could put a bit of film or + + + align:start position:0% +okay so you could put a bit of film or +something like here in practice you + + align:start position:0% +something like here in practice you + + + align:start position:0% +something like here in practice you +can't because it's right next to plasma + + align:start position:0% +can't because it's right next to plasma + + + align:start position:0% +can't because it's right next to plasma +so you need some sort of lens optic this + + align:start position:0% +so you need some sort of lens optic this + + + align:start position:0% +so you need some sort of lens optic this +technique actually looks a great deal + + align:start position:0% +technique actually looks a great deal + + + align:start position:0% +technique actually looks a great deal +like proton radiography which we'll talk + + align:start position:0% +like proton radiography which we'll talk + + + align:start position:0% +like proton radiography which we'll talk +about later on here in proton + + align:start position:0% +about later on here in proton + + + align:start position:0% +about later on here in proton +radiography you don't have any lenses + + align:start position:0% +radiography you don't have any lenses + + + align:start position:0% +radiography you don't have any lenses +you can't it's very difficult to make + + align:start position:0% +you can't it's very difficult to make + + + align:start position:0% +you can't it's very difficult to make +lenses for charge particles uh and so + + align:start position:0% +lenses for charge particles uh and so + + + align:start position:0% +lenses for charge particles uh and so +you do in fact put your bit of paper + + align:start position:0% +you do in fact put your bit of paper + + + align:start position:0% +you do in fact put your bit of paper +like your your film in this case very + + align:start position:0% +like your your film in this case very + + + align:start position:0% +like your your film in this case very +close to your plasma you might put a + + align:start position:0% +close to your plasma you might put a + + + align:start position:0% +close to your plasma you might put a +little bit further back and we'll talk + + align:start position:0% +little bit further back and we'll talk + + + align:start position:0% +little bit further back and we'll talk +in a moment about actually how important + + align:start position:0% +in a moment about actually how important + + + align:start position:0% +in a moment about actually how important +is your choice of exactly where you put + + align:start position:0% +is your choice of exactly where you put + + + align:start position:0% +is your choice of exactly where you put +your detector because I could put my + + align:start position:0% +your detector because I could put my + + + align:start position:0% +your detector because I could put my +detector here or here or here and I + + align:start position:0% +detector here or here or here and I + + + align:start position:0% +detector here or here or here and I +still get an image forming but the image + + align:start position:0% +still get an image forming but the image + + + align:start position:0% +still get an image forming but the image +will look different but yeah we do not + + align:start position:0% +will look different but yeah we do not + + + align:start position:0% +will look different but yeah we do not +need the lens Sol phography but in + + align:start position:0% +need the lens Sol phography but in + + + align:start position:0% +need the lens Sol phography but in +almost all realistic setups where we're + + align:start position:0% +almost all realistic setups where we're + + + align:start position:0% +almost all realistic setups where we're +using some probing beam through a plasma + + align:start position:0% +using some probing beam through a plasma + + + align:start position:0% +using some probing beam through a plasma +we're going to have a lens because it + + align:start position:0% +we're going to have a lens because it + + + align:start position:0% +we're going to have a lens because it +allows us to put our detector nice and + + align:start position:0% +allows us to put our detector nice and + + + align:start position:0% +allows us to put our detector nice and +far away and safe in the plasma yeah + + align:start position:0% +far away and safe in the plasma yeah + + + align:start position:0% +far away and safe in the plasma yeah +cool other + + align:start position:0% + + + + align:start position:0% + +questions anyone from Columbia + + align:start position:0% + + + + align:start position:0% + +I don't see anyone so I'm going to keep + + align:start position:0% +I don't see anyone so I'm going to keep + + + align:start position:0% +I don't see anyone so I'm going to keep +going + + align:start position:0% +going + + + align:start position:0% +going +cool so let me raise this + + align:start position:0% + + + + align:start position:0% + +side so as I just mentioned then we can + + align:start position:0% +side so as I just mentioned then we can + + + align:start position:0% +side so as I just mentioned then we can +actually change the shadow graphic image + + align:start position:0% +actually change the shadow graphic image + + + align:start position:0% +actually change the shadow graphic image +we get by moving the position of our + + align:start position:0% +we get by moving the position of our + + + align:start position:0% +we get by moving the position of our +object PL so that could be moving our + + align:start position:0% +object PL so that could be moving our + + + align:start position:0% +object PL so that could be moving our +detector if we've just placed a detector + + align:start position:0% +detector if we've just placed a detector + + + align:start position:0% +detector if we've just placed a detector +here or it could be by moving our lens + + align:start position:0% +here or it could be by moving our lens + + + align:start position:0% +here or it could be by moving our lens +because as we move the lens we change + + align:start position:0% +because as we move the lens we change + + + align:start position:0% +because as we move the lens we change +the place we're focusing on or we could + + align:start position:0% +the place we're focusing on or we could + + + align:start position:0% +the place we're focusing on or we could +move other anyway you get the idea + + align:start position:0% +move other anyway you get the idea + + + align:start position:0% +move other anyway you get the idea +there's lots of different ways of moving + + align:start position:0% +there's lots of different ways of moving + + + align:start position:0% +there's lots of different ways of moving +it some of a place so let's have a look + + align:start position:0% +it some of a place so let's have a look + + + align:start position:0% +it some of a place so let's have a look +here we've got again our + + align:start position:0% + + + + align:start position:0% + +plasma and we've got our Rays coming + + align:start position:0% +plasma and we've got our Rays coming + + + align:start position:0% +plasma and we've got our Rays coming +through + + align:start position:0% + + + + align:start position:0% + +it we got a ray that gets deflected + + align:start position:0% +it we got a ray that gets deflected + + + align:start position:0% +it we got a ray that gets deflected +downwards and array that gets deflected + + align:start position:0% +downwards and array that gets deflected + + + align:start position:0% +downwards and array that gets deflected +upwards and another one that gets + + align:start position:0% +upwards and another one that gets + + + align:start position:0% +upwards and another one that gets +deflected down like this I can draw some + + align:start position:0% +deflected down like this I can draw some + + + align:start position:0% +deflected down like this I can draw some +different planes in which we can put our + + align:start position:0% +different planes in which we can put our + + + align:start position:0% +different planes in which we can put our +detector let me just get them in the + + align:start position:0% +detector let me just get them in the + + + align:start position:0% +detector let me just get them in the +right + + align:start position:0% + + + + align:start position:0% + +places and maybe I can call these one + + align:start position:0% +places and maybe I can call these one + + + align:start position:0% +places and maybe I can call these one +two + + align:start position:0% +two + + + align:start position:0% +two +3 and four like that and so then we can + + align:start position:0% +3 and four like that and so then we can + + + align:start position:0% +3 and four like that and so then we can +have a look at what would we see for + + align:start position:0% +have a look at what would we see for + + + align:start position:0% +have a look at what would we see for +this very simple system where we've got + + align:start position:0% +this very simple system where we've got + + + align:start position:0% +this very simple system where we've got +some sort of focusing density gradients + + align:start position:0% +some sort of focusing density gradients + + + align:start position:0% +some sort of focusing density gradients +and some defocusing density gradient + + align:start position:0% +and some defocusing density gradient + + + align:start position:0% +and some defocusing density gradient +here so this could be a + + align:start position:0% +here so this could be a + + + align:start position:0% +here so this could be a +Maxima in the electron density and this + + align:start position:0% +Maxima in the electron density and this + + + align:start position:0% +Maxima in the electron density and this +would be a Minima here right so that we + + align:start position:0% +would be a Minima here right so that we + + + align:start position:0% +would be a Minima here right so that we +would get focusing focusing um so let's + + align:start position:0% +would get focusing focusing um so let's + + + align:start position:0% +would get focusing focusing um so let's +draw what those patterns would look like + + align:start position:0% +draw what those patterns would look like + + + align:start position:0% +draw what those patterns would look like +so if I + + align:start position:0% +so if I + + + align:start position:0% +so if I +have intensity like + + align:start position:0% +have intensity like + + + align:start position:0% +have intensity like +this and let's say that this is the + + align:start position:0% +this and let's say that this is the + + + align:start position:0% +this and let's say that this is the +y-coordinate that's I call this + + align:start position:0% +y-coordinate that's I call this + + + align:start position:0% +y-coordinate that's I call this +y here and I'll do the first one here + + align:start position:0% +y here and I'll do the first one here + + + align:start position:0% +y here and I'll do the first one here +we'll get something uh we're going to + + align:start position:0% +we'll get something uh we're going to + + + align:start position:0% +we'll get something uh we're going to +have a little bit of deficit of + + align:start position:0% +have a little bit of deficit of + + + align:start position:0% +have a little bit of deficit of +intensity round about here because the + + align:start position:0% +intensity round about here because the + + + align:start position:0% +intensity round about here because the +ray is being deflected away so if this + + align:start position:0% +ray is being deflected away so if this + + + align:start position:0% +ray is being deflected away so if this +is the background intensity of our + + align:start position:0% +is the background intensity of our + + + align:start position:0% +is the background intensity of our +probing being will have some sort of + + align:start position:0% +probing being will have some sort of + + + align:start position:0% +probing being will have some sort of +drop uh and then we'll have an increase + + align:start position:0% +drop uh and then we'll have an increase + + + align:start position:0% +drop uh and then we'll have an increase +because the light is being focused + + align:start position:0% +because the light is being focused + + + align:start position:0% +because the light is being focused +together in the middle here we'll have + + align:start position:0% +together in the middle here we'll have + + + align:start position:0% +together in the middle here we'll have +another deficit in this region and we'll + + align:start position:0% +another deficit in this region and we'll + + + align:start position:0% +another deficit in this region and we'll +have another little increase over there + + align:start position:0% +have another little increase over there + + + align:start position:0% +have another little increase over there +so we get some + + align:start position:0% +so we get some + + + align:start position:0% +so we get some +nice little modulation what it's looking + + align:start position:0% +nice little modulation what it's looking + + + align:start position:0% +nice little modulation what it's looking +like if we go to two we can see that the + + align:start position:0% +like if we go to two we can see that the + + + align:start position:0% +like if we go to two we can see that the +rays are now getting closer together and + + align:start position:0% +rays are now getting closer together and + + + align:start position:0% +rays are now getting closer together and +further apart so you'd expect for this + + align:start position:0% +further apart so you'd expect for this + + + align:start position:0% +further apart so you'd expect for this +pattern to be even more exaggerated + + align:start position:0% +pattern to be even more exaggerated + + + align:start position:0% +pattern to be even more exaggerated +maybe I should have drawn this less + + align:start position:0% +maybe I should have drawn this less + + + align:start position:0% +maybe I should have drawn this less +exaggerated to give myself more space + + align:start position:0% +exaggerated to give myself more space + + + align:start position:0% +exaggerated to give myself more space +but let's say it looks + + align:start position:0% +but let's say it looks + + + align:start position:0% +but let's say it looks +like like this and this is this is + + align:start position:0% +like like this and this is this is + + + align:start position:0% +like like this and this is this is +bigger if we get over to three now you + + align:start position:0% +bigger if we get over to three now you + + + align:start position:0% +bigger if we get over to three now you +see something interesting we actually + + align:start position:0% +see something interesting we actually + + + align:start position:0% +see something interesting we actually +have Rays crossing here so this means a + + align:start position:0% +have Rays crossing here so this means a + + + align:start position:0% +have Rays crossing here so this means a +lot of light is all piled into the same + + align:start position:0% +lot of light is all piled into the same + + + align:start position:0% +lot of light is all piled into the same +place so we're still going to have a + + align:start position:0% +place so we're still going to have a + + + align:start position:0% +place so we're still going to have a +little bit of defocusing but we're going + + align:start position:0% +little bit of defocusing but we're going + + + align:start position:0% +little bit of defocusing but we're going +to have a very sharp Spike here which + + align:start position:0% +to have a very sharp Spike here which + + + align:start position:0% +to have a very sharp Spike here which +goes off my page and then we don't + + align:start position:0% +goes off my page and then we don't + + + align:start position:0% +goes off my page and then we don't +really have so much precise focusing + + align:start position:0% +really have so much precise focusing + + + align:start position:0% +really have so much precise focusing +down here but maybe there's a little bit + + align:start position:0% +down here but maybe there's a little bit + + + align:start position:0% +down here but maybe there's a little bit +of light so like that and then the + + align:start position:0% +of light so like that and then the + + + align:start position:0% +of light so like that and then the +number + + align:start position:0% + + + + align:start position:0% + +four we've got away from having this + + align:start position:0% +four we've got away from having this + + + align:start position:0% +four we've got away from having this +crossing here so we won't see it so + + align:start position:0% +crossing here so we won't see it so + + + align:start position:0% +crossing here so we won't see it so +strongly it's going to look a little bit + + align:start position:0% +strongly it's going to look a little bit + + + align:start position:0% +strongly it's going to look a little bit +more like this um so something maybe a + + align:start position:0% +more like this um so something maybe a + + + align:start position:0% +more like this um so something maybe a +little bit + + align:start position:0% + + + + align:start position:0% + +like that now one thing I haven't really + + align:start position:0% +like that now one thing I haven't really + + + align:start position:0% +like that now one thing I haven't really +exaggerated enough here is the fact that + + align:start position:0% +exaggerated enough here is the fact that + + + align:start position:0% +exaggerated enough here is the fact that +as these Rays move outwards the + + align:start position:0% +as these Rays move outwards the + + + align:start position:0% +as these Rays move outwards the +positions of these Maxima and Minima are + + align:start position:0% +positions of these Maxima and Minima are + + + align:start position:0% +positions of these Maxima and Minima are +changing so in reality maybe this one is + + align:start position:0% +changing so in reality maybe this one is + + + align:start position:0% +changing so in reality maybe this one is +a little bit closer in and then I'll + + align:start position:0% +a little bit closer in and then I'll + + + align:start position:0% +a little bit closer in and then I'll +make these one go further out so you can + + align:start position:0% +make these one go further out so you can + + + align:start position:0% +make these one go further out so you can +see that actually the + + align:start position:0% +see that actually the + + + align:start position:0% +see that actually the +position of where we get Peak intensity + + align:start position:0% +position of where we get Peak intensity + + + align:start position:0% +position of where we get Peak intensity +is going to change depending on how far + + align:start position:0% +is going to change depending on how far + + + align:start position:0% +is going to change depending on how far +away we are from the because the Rays + + align:start position:0% +away we are from the because the Rays + + + align:start position:0% +away we are from the because the Rays +have traveled and so their displacement + + align:start position:0% +have traveled and so their displacement + + + align:start position:0% +have traveled and so their displacement +has changed as + + align:start position:0% +has changed as + + + align:start position:0% +has changed as +well so there's a lot going on inside + + align:start position:0% +well so there's a lot going on inside + + + align:start position:0% +well so there's a lot going on inside +here you can see that there's a lot of + + align:start position:0% +here you can see that there's a lot of + + + align:start position:0% +here you can see that there's a lot of +richness and you can see that although + + align:start position:0% +richness and you can see that although + + + align:start position:0% +richness and you can see that although +we can identify why there are light and + + align:start position:0% +we can identify why there are light and + + + align:start position:0% +we can identify why there are light and +dark regions inside our image it's hard + + align:start position:0% +dark regions inside our image it's hard + + + align:start position:0% +dark regions inside our image it's hard +to map them directly back onto + + align:start position:0% +to map them directly back onto + + + align:start position:0% +to map them directly back onto +whatever's going on inside the plasma + + align:start position:0% +whatever's going on inside the plasma + + + align:start position:0% +whatever's going on inside the plasma +and again that's because as I said this + + align:start position:0% +and again that's because as I said this + + + align:start position:0% +and again that's because as I said this +is not an image you can tell it's not an + + align:start position:0% +is not an image you can tell it's not an + + + align:start position:0% +is not an image you can tell it's not an +image because if you move your detector + + align:start position:0% +image because if you move your detector + + + align:start position:0% +image because if you move your detector +or if you move where your + + align:start position:0% +or if you move where your + + + align:start position:0% +or if you move where your +the data you get a very different + + align:start position:0% +the data you get a very different + + + align:start position:0% +the data you get a very different +picture out here so although this Maxima + + align:start position:0% +picture out here so although this Maxima + + + align:start position:0% +picture out here so although this Maxima +here corresponds + + align:start position:0% +here corresponds + + + align:start position:0% +here corresponds +to this region of the plasma it shows up + + align:start position:0% +to this region of the plasma it shows up + + + align:start position:0% +to this region of the plasma it shows up +at different positions on your detector + + align:start position:0% +at different positions on your detector + + + align:start position:0% +at different positions on your detector +different places so you can't really say + + align:start position:0% +different places so you can't really say + + + align:start position:0% +different places so you can't really say +this is a direct image it is a bjective + + align:start position:0% +this is a direct image it is a bjective + + + align:start position:0% +this is a direct image it is a bjective +so this is + + align:start position:0% +so this is + + + align:start position:0% +so this is +means that at least + + align:start position:0% +means that at least + + + align:start position:0% +means that at least +for these smaller flections we have + + align:start position:0% +for these smaller flections we have + + + align:start position:0% +for these smaller flections we have +what's call a one for one + + align:start position:0% + + + + align:start position:0% + +mapping that's only true for the small + + align:start position:0% +mapping that's only true for the small + + + align:start position:0% +mapping that's only true for the small +deflections one and two like that for + + align:start position:0% +deflections one and two like that for + + + align:start position:0% +deflections one and two like that for +these two slices here once we get to + + align:start position:0% +these two slices here once we get to + + + align:start position:0% +these two slices here once we get to +three and we have the Rays Crossing you + + align:start position:0% +three and we have the Rays Crossing you + + + align:start position:0% +three and we have the Rays Crossing you +can see that at this point light which + + align:start position:0% +can see that at this point light which + + + align:start position:0% +can see that at this point light which +is coming from these two regions now + + align:start position:0% +is coming from these two regions now + + + align:start position:0% +is coming from these two regions now +Maps into the same place on our image or + + align:start position:0% +Maps into the same place on our image or + + + align:start position:0% +Maps into the same place on our image or +on our uh on our detector and so we no + + align:start position:0% +on our uh on our detector and so we no + + + align:start position:0% +on our uh on our detector and so we no +longer have that one to one m and indeed + + align:start position:0% +longer have that one to one m and indeed + + + align:start position:0% +longer have that one to one m and indeed +after the Rays have crossed these two + + align:start position:0% +after the Rays have crossed these two + + + align:start position:0% +after the Rays have crossed these two +cross over and so it's very confusing + + align:start position:0% +cross over and so it's very confusing + + + align:start position:0% +cross over and so it's very confusing +looking at this and trying to work out + + align:start position:0% +looking at this and trying to work out + + + align:start position:0% +looking at this and trying to work out +where all the light has come from + + align:start position:0% +where all the light has come from + + + align:start position:0% +where all the light has come from +although we do have this oneto one map + + align:start position:0% +although we do have this oneto one map + + + align:start position:0% +although we do have this oneto one map +for one and two so you know in principle + + align:start position:0% +for one and two so you know in principle + + + align:start position:0% +for one and two so you know in principle +we can sort of work out where everything + + align:start position:0% +we can sort of work out where everything + + + align:start position:0% +we can sort of work out where everything +came from it doesn't have properties + + align:start position:0% +came from it doesn't have properties + + + align:start position:0% +came from it doesn't have properties +that we normally like to have from an + + align:start position:0% +that we normally like to have from an + + + align:start position:0% +that we normally like to have from an +image so for example parallel lines do + + align:start position:0% +image so for example parallel lines do + + + align:start position:0% +image so for example parallel lines do +not go + + align:start position:0% +not go + + + align:start position:0% +not go +to parallel lines from the object plane + + align:start position:0% +to parallel lines from the object plane + + + align:start position:0% +to parallel lines from the object plane +to the image plane as we sort of + + align:start position:0% +to the image plane as we sort of + + + align:start position:0% +to the image plane as we sort of +discussed over here and so you might + + align:start position:0% +discussed over here and so you might + + + align:start position:0% +discussed over here and so you might +want that in the normal Imaging + + align:start position:0% +want that in the normal Imaging + + + align:start position:0% +want that in the normal Imaging +diagnostic you want to take a picture of + + align:start position:0% +diagnostic you want to take a picture of + + + align:start position:0% +diagnostic you want to take a picture of +a square and it comes out looking like + + align:start position:0% +a square and it comes out looking like + + + align:start position:0% +a square and it comes out looking like +something spaghetti that's not really an + + align:start position:0% +something spaghetti that's not really an + + + align:start position:0% +something spaghetti that's not really an +image and also the length not + + align:start position:0% + + + + align:start position:0% + +preserved things get even + + align:start position:0% +preserved things get even + + + align:start position:0% +preserved things get even +worse + + align:start position:0% +worse + + + align:start position:0% +worse +preserved things get even worse for um + + align:start position:0% +preserved things get even worse for um + + + align:start position:0% +preserved things get even worse for um +three and + + align:start position:0% + + + + align:start position:0% + +four because now we don't even have this + + align:start position:0% +four because now we don't even have this + + + align:start position:0% +four because now we don't even have this +BCC property we end up in a regime which + + align:start position:0% +BCC property we end up in a regime which + + + align:start position:0% +BCC property we end up in a regime which +is called the coric regime which I'll + + align:start position:0% +is called the coric regime which I'll + + + align:start position:0% +is called the coric regime which I'll +talk more about + + align:start position:0% + + + + align:start position:0% + +later course stics come up all the time + + align:start position:0% +later course stics come up all the time + + + align:start position:0% +later course stics come up all the time +in other fields that are sometimes + + align:start position:0% +in other fields that are sometimes + + + align:start position:0% +in other fields that are sometimes +called Optical catastrophes um and + + align:start position:0% +called Optical catastrophes um and + + + align:start position:0% +called Optical catastrophes um and +although they're very very pretty they + + align:start position:0% +although they're very very pretty they + + + align:start position:0% +although they're very very pretty they +do make analysis of this data very very + + align:start position:0% +do make analysis of this data very very + + + align:start position:0% +do make analysis of this data very very +difficult so what I'm trying to show + + align:start position:0% +difficult so what I'm trying to show + + + align:start position:0% +difficult so what I'm trying to show +here is something as simple as moving + + align:start position:0% +here is something as simple as moving + + + align:start position:0% +here is something as simple as moving +exactly where you make this measurement + + align:start position:0% +exactly where you make this measurement + + + align:start position:0% +exactly where you make this measurement +makes a big difference to the data that + + align:start position:0% +makes a big difference to the data that + + + align:start position:0% +makes a big difference to the data that +you have it turns out that the easiest + + align:start position:0% +you have it turns out that the easiest + + + align:start position:0% +you have it turns out that the easiest +place theoretically to analyze your data + + align:start position:0% +place theoretically to analyze your data + + + align:start position:0% +place theoretically to analyze your data +is nice and close to your plasma but the + + align:start position:0% +is nice and close to your plasma but the + + + align:start position:0% +is nice and close to your plasma but the +easiest place that actually make the + + align:start position:0% +easiest place that actually make the + + + align:start position:0% +easiest place that actually make the +measurement with decent signals and + + align:start position:0% +measurement with decent signals and + + + align:start position:0% +measurement with decent signals and +noise is somewhere around about three so + + align:start position:0% +noise is somewhere around about three so + + + align:start position:0% +noise is somewhere around about three so +you can't have it all um you can't end + + align:start position:0% +you can't have it all um you can't end + + + align:start position:0% +you can't have it all um you can't end +up in a regime where you have the + + align:start position:0% +up in a regime where you have the + + + align:start position:0% +up in a regime where you have the +absolute best + + align:start position:0% + + + + align:start position:0% + +dat again this has all been very + + align:start position:0% +dat again this has all been very + + + align:start position:0% +dat again this has all been very +qualitative we're about to make it + + align:start position:0% +qualitative we're about to make it + + + align:start position:0% +qualitative we're about to make it +quantitative by showing at least in this + + align:start position:0% +quantitative by showing at least in this + + + align:start position:0% +quantitative by showing at least in this +small deflection regime uh what you can + + align:start position:0% +small deflection regime uh what you can + + + align:start position:0% +small deflection regime uh what you can +measure but does anyone have any + + align:start position:0% +measure but does anyone have any + + + align:start position:0% +measure but does anyone have any +questions on this General schema before + + align:start position:0% +questions on this General schema before + + + align:start position:0% +questions on this General schema before +we could go yeah are you saying that + + align:start position:0% +we could go yeah are you saying that + + + align:start position:0% +we could go yeah are you saying that +there's a bjective map between your + + align:start position:0% +there's a bjective map between your + + + align:start position:0% +there's a bjective map between your +measured intensity distribution and + + align:start position:0% +measured intensity distribution and + + + align:start position:0% +measured intensity distribution and +incident intensity distribution or + + align:start position:0% +incident intensity distribution or + + + align:start position:0% +incident intensity distribution or +between the measured intensity + + align:start position:0% +between the measured intensity + + + align:start position:0% +between the measured intensity +distribution and the plasma density + + align:start position:0% +distribution and the plasma density + + + align:start position:0% +distribution and the plasma density +profile really the former so between the + + align:start position:0% +profile really the former so between the + + + align:start position:0% +profile really the former so between the +incident laser the laser on this side + + align:start position:0% +incident laser the laser on this side + + + align:start position:0% +incident laser the laser on this side +and on this side but I would argue that + + align:start position:0% +and on this side but I would argue that + + + align:start position:0% +and on this side but I would argue that +if you have that you can then infer + + align:start position:0% +if you have that you can then infer + + + align:start position:0% +if you have that you can then infer +something about the plasma that you've + + align:start position:0% +something about the plasma that you've + + + align:start position:0% +something about the plasma that you've +gone through because you have some idea + + align:start position:0% +gone through because you have some idea + + + align:start position:0% +gone through because you have some idea +of if you're measuring here and you know + + align:start position:0% +of if you're measuring here and you know + + + align:start position:0% +of if you're measuring here and you know +it corresponds to here then you know + + align:start position:0% +it corresponds to here then you know + + + align:start position:0% +it corresponds to here then you know +that the cord that you took to the + + align:start position:0% +that the cord that you took to the + + + align:start position:0% +that the cord that you took to the +plasma was roughly that right so you + + align:start position:0% +plasma was roughly that right so you + + + align:start position:0% +plasma was roughly that right so you +have some idea of like what sort of + + align:start position:0% +have some idea of like what sort of + + + align:start position:0% +have some idea of like what sort of +plasma properties you were sensing or + + align:start position:0% +plasma properties you were sensing or + + + align:start position:0% +plasma properties you were sensing or +alternative way around you have some + + align:start position:0% +alternative way around you have some + + + align:start position:0% +alternative way around you have some +idea that if you ended up here that you + + align:start position:0% +idea that if you ended up here that you + + + align:start position:0% +idea that if you ended up here that you +must have gone through this bit of + + align:start position:0% +must have gone through this bit of + + + align:start position:0% +must have gone through this bit of +plasma and to get that displacement that + + align:start position:0% +plasma and to get that displacement that + + + align:start position:0% +plasma and to get that displacement that +bit of plasma must have had some Pro + + align:start position:0% +bit of plasma must have had some Pro + + + align:start position:0% +bit of plasma must have had some Pro +certain density gradients within it + + align:start position:0% +certain density gradients within it + + + align:start position:0% +certain density gradients within it +right like some sort of average density + + align:start position:0% +right like some sort of average density + + + align:start position:0% +right like some sort of average density +gradient yes exactly all this is all + + align:start position:0% +gradient yes exactly all this is all + + + align:start position:0% +gradient yes exactly all this is all +line integrated and we'll talk about + + align:start position:0% +line integrated and we'll talk about + + + align:start position:0% +line integrated and we'll talk about +that in moment when we we we'll make + + align:start position:0% +that in moment when we we we'll make + + + align:start position:0% +that in moment when we we we'll make +this displacement we will work out I + + align:start position:0% +this displacement we will work out I + + + align:start position:0% +this displacement we will work out I +guess it's a y is it it's a y axis we + + align:start position:0% +guess it's a y is it it's a y axis we + + + align:start position:0% +guess it's a y is it it's a y axis we +will work out what that displacement is + + align:start position:0% +will work out what that displacement is + + + align:start position:0% +will work out what that displacement is +in terms of the plasma parameters so + + align:start position:0% +in terms of the plasma parameters so + + + align:start position:0% +in terms of the plasma parameters so +we'll make that quenta but yeah this is + + align:start position:0% +we'll make that quenta but yeah this is + + + align:start position:0% +we'll make that quenta but yeah this is +this is kind of what I'm getting at is + + align:start position:0% +this is kind of what I'm getting at is + + + align:start position:0% +this is kind of what I'm getting at is +you have some idea of what you're + + align:start position:0% +you have some idea of what you're + + + align:start position:0% +you have some idea of what you're +actually measuring once you get into + + align:start position:0% +actually measuring once you get into + + + align:start position:0% +actually measuring once you get into +this costic regime you don't really know + + align:start position:0% +this costic regime you don't really know + + + align:start position:0% +this costic regime you don't really know +exactly where everything has come from + + align:start position:0% +exactly where everything has come from + + + align:start position:0% +exactly where everything has come from +anymore yeah sorry I saw that hand first + + align:start position:0% +anymore yeah sorry I saw that hand first + + + align:start position:0% +anymore yeah sorry I saw that hand first +um yeah is the intensity still + + align:start position:0% +um yeah is the intensity still + + + align:start position:0% +um yeah is the intensity still +proportional to the density gradient as + + align:start position:0% +proportional to the density gradient as + + + align:start position:0% +proportional to the density gradient as +it was previously or is it I'm sad that + + align:start position:0% +it was previously or is it I'm sad that + + + align:start position:0% +it was previously or is it I'm sad that +you took away from my previous lecture + + align:start position:0% +you took away from my previous lecture + + + align:start position:0% +you took away from my previous lecture +the in and the intensity proportional + + align:start position:0% +the in and the intensity proportional + + + align:start position:0% +the in and the intensity proportional +density gradient it almost never is in + + align:start position:0% +density gradient it almost never is in + + + align:start position:0% +density gradient it almost never is in +any realistic situation so that's not + + align:start position:0% +any realistic situation so that's not + + + align:start position:0% +any realistic situation so that's not +true and it's still not true here and we + + align:start position:0% +true and it's still not true here and we + + + align:start position:0% +true and it's still not true here and we +will derive that it's proportional to + + align:start position:0% +will derive that it's proportional to + + + align:start position:0% +will derive that it's proportional to +the second derivative of the density + + align:start position:0% +the second derivative of the density + + + align:start position:0% +the second derivative of the density +gradient and we'll also show that that + + align:start position:0% +gradient and we'll also show that that + + + align:start position:0% +gradient and we'll also show that that +is also not true in most reasonable + + align:start position:0% +is also not true in most reasonable + + + align:start position:0% +is also not true in most reasonable +cases so please take away from this that + + align:start position:0% +cases so please take away from this that + + + align:start position:0% +cases so please take away from this that +NE of these Diagnostics are easy to + + align:start position:0% +NE of these Diagnostics are easy to + + + align:start position:0% +NE of these Diagnostics are easy to +interpret but you will read in the + + align:start position:0% +interpret but you will read in the + + + align:start position:0% +interpret but you will read in the +textbooks or online that they're + + align:start position:0% +textbooks or online that they're + + + align:start position:0% +textbooks or online that they're +proportional to the first Der or the + + align:start position:0% +proportional to the first Der or the + + + align:start position:0% +proportional to the first Der or the +second derivative it's almost impossible + + align:start position:0% +second derivative it's almost impossible + + + align:start position:0% +second derivative it's almost impossible +to set your diagnostic such that that's + + align:start position:0% +to set your diagnostic such that that's + + + align:start position:0% +to set your diagnostic such that that's +actually true so + + align:start position:0% +actually true so + + + align:start position:0% +actually true so +cool so you say that if we are like two + + align:start position:0% +cool so you say that if we are like two + + + align:start position:0% +cool so you say that if we are like two +we can guess that it's coming from the + + align:start position:0% +we can guess that it's coming from the + + + align:start position:0% +we can guess that it's coming from the +first Ray but how can we say that why + + align:start position:0% +first Ray but how can we say that why + + + align:start position:0% +first Ray but how can we say that why +can't we say that it's like the lower + + align:start position:0% +can't we say that it's like the lower + + + align:start position:0% +can't we say that it's like the lower +Ray incredibly deflected up so how can + + align:start position:0% +Ray incredibly deflected up so how can + + + align:start position:0% +Ray incredibly deflected up so how can +we know where regime is yeah absolutely + + align:start position:0% +we know where regime is yeah absolutely + + + align:start position:0% +we know where regime is yeah absolutely +yeah so that's a great point so it is + + align:start position:0% +yeah so that's a great point so it is + + + align:start position:0% +yeah so that's a great point so it is +very hard to find the costic regime but + + align:start position:0% +very hard to find the costic regime but + + + align:start position:0% +very hard to find the costic regime but +the costic regime is defin by extreme + + align:start position:0% +the costic regime is defin by extreme + + + align:start position:0% +the costic regime is defin by extreme +intensity variations so if you see only + + align:start position:0% +intensity variations so if you see only + + + align:start position:0% +intensity variations so if you see only +small intensity variations you can't be + + align:start position:0% +small intensity variations you can't be + + + align:start position:0% +small intensity variations you can't be +in the cost + + align:start position:0% +in the cost + + + align:start position:0% +in the cost +regime you know theoretically this is a + + align:start position:0% +regime you know theoretically this is a + + + align:start position:0% +regime you know theoretically this is a +a spike to Infinity right fortunately + + align:start position:0% +a spike to Infinity right fortunately + + + align:start position:0% +a spike to Infinity right fortunately +the universe doesn't allow that to + + align:start position:0% +the universe doesn't allow that to + + + align:start position:0% +the universe doesn't allow that to +happen because your Optics aren't + + align:start position:0% +happen because your Optics aren't + + + align:start position:0% +happen because your Optics aren't +perfect and your detect isn't perfect + + align:start position:0% +perfect and your detect isn't perfect + + + align:start position:0% +perfect and your detect isn't perfect +but this is very very bright so you can + + align:start position:0% +but this is very very bright so you can + + + align:start position:0% +but this is very very bright so you can +tell by looking at an image if it's got + + align:start position:0% +tell by looking at an image if it's got + + + align:start position:0% +tell by looking at an image if it's got +no hugely bright regions you're not in + + align:start position:0% +no hugely bright regions you're not in + + + align:start position:0% +no hugely bright regions you're not in +this regime and then the your second + + align:start position:0% +this regime and then the your second + + + align:start position:0% +this regime and then the your second +question was yeah but still it could + + align:start position:0% +question was yeah but still it could + + + align:start position:0% +question was yeah but still it could +come from somewhere else you're right we + + align:start position:0% +come from somewhere else you're right we + + + align:start position:0% +come from somewhere else you're right we +when we talk about uh some of the + + align:start position:0% +when we talk about uh some of the + + + align:start position:0% +when we talk about uh some of the +advanced methods for I guess + + align:start position:0% +advanced methods for I guess + + + align:start position:0% +advanced methods for I guess +deconvolving or processing this data we + + align:start position:0% +deconvolving or processing this data we + + + align:start position:0% +deconvolving or processing this data we +will come across uh some long exciting + + align:start position:0% +will come across uh some long exciting + + + align:start position:0% +will come across uh some long exciting +sounding phrases like Optimal transport + + align:start position:0% +sounding phrases like Optimal transport + + + align:start position:0% +sounding phrases like Optimal transport +and poroid diagrams and there you're + + align:start position:0% +and poroid diagrams and there you're + + + align:start position:0% +and poroid diagrams and there you're +trying to like minimize how ridiculous + + align:start position:0% +trying to like minimize how ridiculous + + + align:start position:0% +trying to like minimize how ridiculous +your density distribution has to be to + + align:start position:0% +your density distribution has to be to + + + align:start position:0% +your density distribution has to be to +give you this result and so there are + + align:start position:0% +give you this result and so there are + + + align:start position:0% +give you this result and so there are +like very mathematically grounded ways + + align:start position:0% +like very mathematically grounded ways + + + align:start position:0% +like very mathematically grounded ways +of trying to put this back but you know + + align:start position:0% +of trying to put this back but you know + + + align:start position:0% +of trying to put this back but you know +if you're just staring at an image and + + align:start position:0% +if you're just staring at an image and + + + align:start position:0% +if you're just staring at an image and +it's got small intensity perturbations + + align:start position:0% +it's got small intensity perturbations + + + align:start position:0% +it's got small intensity perturbations +you're probably be like hey you know + + align:start position:0% +you're probably be like hey you know + + + align:start position:0% +you're probably be like hey you know +it's most likely to have come from up + + align:start position:0% +it's most likely to have come from up + + + align:start position:0% +it's most likely to have come from up +here it's unlikely it went whoop like + + align:start position:0% +here it's unlikely it went whoop like + + + align:start position:0% +here it's unlikely it went whoop like +that so if the we we image like way far + + align:start position:0% +that so if the we we image like way far + + + align:start position:0% +that so if the we we image like way far +to the right then it would start to look + + align:start position:0% +to the right then it would start to look + + + align:start position:0% +to the right then it would start to look +more reasonable right but then image + + align:start position:0% +more reasonable right but then image + + + align:start position:0% +more reasonable right but then image +would + + align:start position:0% +would + + + align:start position:0% +would +have yes what I haven't drawn this if I + + align:start position:0% +have yes what I haven't drawn this if I + + + align:start position:0% +have yes what I haven't drawn this if I +draw in more Rays there will actually be + + align:start position:0% +draw in more Rays there will actually be + + + align:start position:0% +draw in more Rays there will actually be +more oh can I do it easily here we'll + + align:start position:0% +more oh can I do it easily here we'll + + + align:start position:0% +more oh can I do it easily here we'll +find out that there are more cor sticks + + align:start position:0% +find out that there are more cor sticks + + + align:start position:0% +find out that there are more cor sticks +coming in later on so once you've gone + + align:start position:0% +coming in later on so once you've gone + + + align:start position:0% +coming in later on so once you've gone +past this point you will always have cor + + align:start position:0% +past this point you will always have cor + + + align:start position:0% +past this point you will always have cor +sticks in here I just I haven't drawn + + align:start position:0% +sticks in here I just I haven't drawn + + + align:start position:0% +sticks in here I just I haven't drawn +enough Rays to make that point really + + align:start position:0% +enough Rays to make that point really + + + align:start position:0% +enough Rays to make that point really +clearly but if you can imagine drawing + + align:start position:0% +clearly but if you can imagine drawing + + + align:start position:0% +clearly but if you can imagine drawing +more in you'll see that they will like + + align:start position:0% +more in you'll see that they will like + + + align:start position:0% +more in you'll see that they will like +maybe there's one that doesn't cross + + align:start position:0% +maybe there's one that doesn't cross + + + align:start position:0% +maybe there's one that doesn't cross +this one here and eventually that + + align:start position:0% +this one here and eventually that + + + align:start position:0% +this one here and eventually that +doesn't work CU it's not a straight line + + align:start position:0% + + + + align:start position:0% + +um like that okay and then this one crop + + align:start position:0% +um like that okay and then this one crop + + + align:start position:0% +um like that okay and then this one crop +is scale we have a cross thing in that + + align:start position:0% +is scale we have a cross thing in that + + + align:start position:0% +is scale we have a cross thing in that +region so they eventually just start + + align:start position:0% +region so they eventually just start + + + align:start position:0% +region so they eventually just start +Crossing more and more and more they + + align:start position:0% +Crossing more and more and more they + + + align:start position:0% +Crossing more and more and more they +will eventually cross and and so I guess + + align:start position:0% +will eventually cross and and so I guess + + + align:start position:0% +will eventually cross and and so I guess +why it says there is always a point some + + align:start position:0% +why it says there is always a point some + + + align:start position:0% +why it says there is always a point some +uh place where you can put your detector + + align:start position:0% +uh place where you can put your detector + + + align:start position:0% +uh place where you can put your detector +back here where you will end up in the + + align:start position:0% +back here where you will end up in the + + + align:start position:0% +back here where you will end up in the +costic raion and there's indeed a + + align:start position:0% +costic raion and there's indeed a + + + align:start position:0% +costic raion and there's indeed a +dimensionist parameter that tells you + + align:start position:0% +dimensionist parameter that tells you + + + align:start position:0% +dimensionist parameter that tells you +whether you're in the CTIC regime or not + + align:start position:0% +whether you're in the CTIC regime or not + + + align:start position:0% +whether you're in the CTIC regime or not +and it's to do with the reflection angle + + align:start position:0% +and it's to do with the reflection angle + + + align:start position:0% +and it's to do with the reflection angle +and this distance actually cool any + + align:start position:0% +and this distance actually cool any + + + align:start position:0% +and this distance actually cool any +other questions anything from + + align:start position:0% + + + + align:start position:0% + +Columbia okay so let's try and make this + + align:start position:0% +Columbia okay so let's try and make this + + + align:start position:0% +Columbia okay so let's try and make this +a bit quantitative because I can see + + align:start position:0% +a bit quantitative because I can see + + + align:start position:0% +a bit quantitative because I can see +that folks want to get some numbers into + + align:start position:0% + + + + align:start position:0% + +this I think here I'm basically + + align:start position:0% +this I think here I'm basically + + + align:start position:0% +this I think here I'm basically +following hutchingson so if you need to + + align:start position:0% +following hutchingson so if you need to + + + align:start position:0% +following hutchingson so if you need to +look up the equations in more detail + + align:start position:0% +look up the equations in more detail + + + align:start position:0% +look up the equations in more detail +this is where you want to head we're + + align:start position:0% +this is where you want to head we're + + + align:start position:0% +this is where you want to head we're +going to be working in a regime + + align:start position:0% +going to be working in a regime + + + align:start position:0% +going to be working in a regime +with small angles so small values of + + align:start position:0% +with small angles so small values of + + + align:start position:0% +with small angles so small values of +theta and remember that Theta is going + + align:start position:0% +theta and remember that Theta is going + + + align:start position:0% +theta and remember that Theta is going +to be equal + + align:start position:0% +to be equal + + + align:start position:0% +to be equal +to I guess I put ddy here but I want to + + align:start position:0% +to I guess I put ddy here but I want to + + + align:start position:0% +to I guess I put ddy here but I want to +make this kind of two-dimensional so I'm + + align:start position:0% +make this kind of two-dimensional so I'm + + + align:start position:0% +make this kind of two-dimensional so I'm +just going to write gradient here and + + align:start position:0% +just going to write gradient here and + + + align:start position:0% +just going to write gradient here and +you can think of theta as a vector which + + align:start position:0% +you can think of theta as a vector which + + + align:start position:0% +you can think of theta as a vector which +contains you know the angle respect to + + align:start position:0% +contains you know the angle respect to + + + align:start position:0% +contains you know the angle respect to +the x- axis and the angle spectral Y + + align:start position:0% +the x- axis and the angle spectral Y + + + align:start position:0% +the x- axis and the angle spectral Y +axis here okay then this is the gradient + + align:start position:0% +axis here okay then this is the gradient + + + align:start position:0% +axis here okay then this is the gradient +of the line integration refractive index + + align:start position:0% +of the line integration refractive index + + + align:start position:0% +of the line integration refractive index +so I'm still going to work in refractive + + align:start position:0% +so I'm still going to work in refractive + + + align:start position:0% +so I'm still going to work in refractive +index here it's a little bit more + + align:start position:0% +index here it's a little bit more + + + align:start position:0% +index here it's a little bit more +Compact and also because this applies to + + align:start position:0% +Compact and also because this applies to + + + align:start position:0% +Compact and also because this applies to +any inhomogenous medium not just a + + align:start position:0% +any inhomogenous medium not just a + + + align:start position:0% +any inhomogenous medium not just a +plasma so you can use this for air and + + align:start position:0% +plasma so you can use this for air and + + + align:start position:0% +plasma so you can use this for air and +all things like that so we going to + + align:start position:0% +all things like that so we going to + + + align:start position:0% +all things like that so we going to +write it just in terms of N and at the + + align:start position:0% +write it just in terms of N and at the + + + align:start position:0% +write it just in terms of N and at the +end I'll turn this into plasma Den so + + align:start position:0% +end I'll turn this into plasma Den so + + + align:start position:0% +end I'll turn this into plasma Den so +you have final + + align:start position:0% +you have final + + + align:start position:0% +you have final +result so we're going to assume that + + align:start position:0% +result so we're going to assume that + + + align:start position:0% +result so we're going to assume that +we've got our rays of + + align:start position:0% +we've got our rays of + + + align:start position:0% +we've got our rays of +light + + align:start position:0% + + + + align:start position:0% + +again incident like this onto + + align:start position:0% +again incident like this onto + + + align:start position:0% +again incident like this onto +some plane that we're going to + + align:start position:0% +some plane that we're going to + + + align:start position:0% +some plane that we're going to +call that has coordinates X and + + align:start position:0% +call that has coordinates X and + + + align:start position:0% +call that has coordinates X and +Y we're going to have some initial + + align:start position:0% +Y we're going to have some initial + + + align:start position:0% +Y we're going to have some initial +intensity + + align:start position:0% + + + + align:start position:0% + +profile that's incident on this plasma + + align:start position:0% +profile that's incident on this plasma + + + align:start position:0% +profile that's incident on this plasma +here so our plasma + + align:start position:0% + + + + align:start position:0% + +rout just past the plane we're doing + + align:start position:0% +rout just past the plane we're doing + + + align:start position:0% +rout just past the plane we're doing +this and of course this could be + + align:start position:0% +this and of course this could be + + + align:start position:0% +this and of course this could be +something nice in uniform or it could be + + align:start position:0% +something nice in uniform or it could be + + + align:start position:0% +something nice in uniform or it could be +gaussian or it could be whatever want so + + align:start position:0% +gaussian or it could be whatever want so + + + align:start position:0% +gaussian or it could be whatever want so +whatever you can actually come up with + + align:start position:0% +whatever you can actually come up with + + + align:start position:0% +whatever you can actually come up with +um for your laser probate and our rays + + align:start position:0% +um for your laser probate and our rays + + + align:start position:0% +um for your laser probate and our rays +are going to get + + align:start position:0% + + + + align:start position:0% + +deflected by some + + align:start position:0% + + + + align:start position:0% + +angle Thea like this and then you know + + align:start position:0% +angle Thea like this and then you know + + + align:start position:0% +angle Thea like this and then you know +we're going to + + align:start position:0% +we're going to + + + align:start position:0% +we're going to +have our detector and that's going to be + + align:start position:0% +have our detector and that's going to be + + + align:start position:0% +have our detector and that's going to be +in a primed coord system X Prime y Prime + + align:start position:0% +in a primed coord system X Prime y Prime + + + align:start position:0% +in a primed coord system X Prime y Prime +and of course if I don't want to put my + + align:start position:0% +and of course if I don't want to put my + + + align:start position:0% +and of course if I don't want to put my +detector just here I can always put a + + align:start position:0% +detector just here I can always put a + + + align:start position:0% +detector just here I can always put a +lens and then I can put my detector here + + align:start position:0% +lens and then I can put my detector here + + + align:start position:0% +lens and then I can put my detector here +and that would also have X Prime y Prime + + align:start position:0% +and that would also have X Prime y Prime + + + align:start position:0% +and that would also have X Prime y Prime +with maybe any magnification that the + + align:start position:0% +with maybe any magnification that the + + + align:start position:0% +with maybe any magnification that the +lens does but that's not really relevant + + align:start position:0% +lens does but that's not really relevant + + + align:start position:0% +lens does but that's not really relevant +for this that's just Optics so we're + + align:start position:0% +for this that's just Optics so we're + + + align:start position:0% +for this that's just Optics so we're +trying to work out how we get from the + + align:start position:0% +trying to work out how we get from the + + + align:start position:0% +trying to work out how we get from the +intensity I initial to the + + align:start position:0% +intensity I initial to the + + + align:start position:0% +intensity I initial to the +intensity what am I going to call it I + + align:start position:0% + + + + align:start position:0% + +detector X Prime y + + align:start position:0% +detector X Prime y + + + align:start position:0% +detector X Prime y +like this okay so we can just stare at + + align:start position:0% +like this okay so we can just stare at + + + align:start position:0% +like this okay so we can just stare at +this and do some simple geometry we can + + align:start position:0% +this and do some simple geometry we can + + + align:start position:0% +this and do some simple geometry we can +say that if we're just talking about + + align:start position:0% +say that if we're just talking about + + + align:start position:0% +say that if we're just talking about +coordinates X Prime y Prime is going to + + align:start position:0% +coordinates X Prime y Prime is going to + + + align:start position:0% +coordinates X Prime y Prime is going to +equal wherever we started out X plus oh + + align:start position:0% +equal wherever we started out X plus oh + + + align:start position:0% +equal wherever we started out X plus oh +this is important we need a link + + align:start position:0% +this is important we need a link + + + align:start position:0% +this is important we need a link +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +scale we're going to put our detector a + + align:start position:0% +scale we're going to put our detector a + + + align:start position:0% +scale we're going to put our detector a +distance L from the plasma here we're + + align:start position:0% +distance L from the plasma here we're + + + align:start position:0% +distance L from the plasma here we're +assuming the plasma is pretty thin still + + align:start position:0% +assuming the plasma is pretty thin still + + + align:start position:0% +assuming the plasma is pretty thin still +so this is going to be + + align:start position:0% +so this is going to be + + + align:start position:0% +so this is going to be +L + + align:start position:0% +L + + + align:start position:0% +L +DD + + align:start position:0% + + + + align:start position:0% + +X of the integral of n + + align:start position:0% +X of the integral of n + + + align:start position:0% +X of the integral of n +DL and the coordinate in y is going to + + align:start position:0% +DL and the coordinate in y is going to + + + align:start position:0% +DL and the coordinate in y is going to +be y plus L * d d y + + align:start position:0% +be y plus L * d d y + + + align:start position:0% +be y plus L * d d y +integral d + + align:start position:0% +integral d + + + align:start position:0% +integral d +l so again I said we're using a small + + align:start position:0% +l so again I said we're using a small + + + align:start position:0% +l so again I said we're using a small +angle approximation so we've taken the + + align:start position:0% +angle approximation so we've taken the + + + align:start position:0% +angle approximation so we've taken the +approximation that tan Theta is a sin + + align:start position:0% +approximation that tan Theta is a sin + + + align:start position:0% +approximation that tan Theta is a sin +Theta is + + align:start position:0% +Theta is + + + align:start position:0% +Theta is +approximately Theta so this is just a + + align:start position:0% +approximately Theta so this is just a + + + align:start position:0% +approximately Theta so this is just a +simple linear relationship here where + + align:start position:0% +simple linear relationship here where + + + align:start position:0% +simple linear relationship here where +this is L * the angle in X and this is L + + align:start position:0% +this is L * the angle in X and this is L + + + align:start position:0% +this is L * the angle in X and this is L +* the angle than + + align:start position:0% +* the angle than + + + align:start position:0% +* the angle than +y + + align:start position:0% +y + + + align:start position:0% +y +y and so we could write this more + + align:start position:0% +y and so we could write this more + + + align:start position:0% +y and so we could write this more +compact in sort of vector notation as + + align:start position:0% +compact in sort of vector notation as + + + align:start position:0% +compact in sort of vector notation as +some Vector X Prime is equal to some + + align:start position:0% +some Vector X Prime is equal to some + + + align:start position:0% +some Vector X Prime is equal to some +Vector X Plus X + + align:start position:0% +Vector X Plus X + + + align:start position:0% +Vector X Plus X +gradient operator + + align:start position:0% + + + + align:start position:0% + +on so this is just another + + align:start position:0% +on so this is just another + + + align:start position:0% +on so this is just another +representation of this okay now one + + align:start position:0% +representation of this okay now one + + + align:start position:0% +representation of this okay now one +thing that we need in order to make some + + align:start position:0% +thing that we need in order to make some + + + align:start position:0% +thing that we need in order to make some +progress here is we need to assume that + + align:start position:0% +progress here is we need to assume that + + + align:start position:0% +progress here is we need to assume that +the overall intensity so the integral of + + align:start position:0% +the overall intensity so the integral of + + + align:start position:0% +the overall intensity so the integral of +this over X and Y is equal to the + + align:start position:0% +this over X and Y is equal to the + + + align:start position:0% +this over X and Y is equal to the +integral of this over X and Y so we sort + + align:start position:0% +integral of this over X and Y so we sort + + + align:start position:0% +integral of this over X and Y so we sort +of conserving our intensity so we could + + align:start position:0% +of conserving our intensity so we could + + + align:start position:0% +of conserving our intensity so we could +write that down as I on the detector + + align:start position:0% +write that down as I on the detector + + + align:start position:0% +write that down as I on the detector +DX Prime d y Prime is equal to I instant + + align:start position:0% +DX Prime d y Prime is equal to I instant + + + align:start position:0% +DX Prime d y Prime is equal to I instant +DX Dy so we the plasma is not absorbing + + align:start position:0% +DX Dy so we the plasma is not absorbing + + + align:start position:0% +DX Dy so we the plasma is not absorbing +and I guess it's also not emitting any + + align:start position:0% +and I guess it's also not emitting any + + + align:start position:0% +and I guess it's also not emitting any +light in this way + + align:start position:0% +light in this way + + + align:start position:0% +light in this way +mation that's a pretty reasonable + + align:start position:0% +mation that's a pretty reasonable + + + align:start position:0% +mation that's a pretty reasonable +proc and then we can skip ahead and we + + align:start position:0% +proc and then we can skip ahead and we + + + align:start position:0% +proc and then we can skip ahead and we +can say that the light which is + + align:start position:0% +can say that the light which is + + + align:start position:0% +can say that the light which is +incident divided the intensity which is + + align:start position:0% +incident divided the intensity which is + + + align:start position:0% +incident divided the intensity which is +incident divided by the intensity our + + align:start position:0% +incident divided by the intensity our + + + align:start position:0% +incident divided by the intensity our +detector is going to be equal to 1 + + align:start position:0% +detector is going to be equal to 1 + + + align:start position:0% +detector is going to be equal to 1 +plus gradient + + align:start position:0% +plus gradient + + + align:start position:0% +plus gradient +squared sorry one + + align:start position:0% +squared sorry one + + + align:start position:0% +squared sorry one +plus L * gradient squ of the integral of + + align:start position:0% +plus L * gradient squ of the integral of + + + align:start position:0% +plus L * gradient squ of the integral of +the refractive index along the path and + + align:start position:0% +the refractive index along the path and + + + align:start position:0% +the refractive index along the path and +if we work with relatively small + + align:start position:0% +if we work with relatively small + + + align:start position:0% +if we work with relatively small +value of this so if we assume that this + + align:start position:0% +value of this so if we assume that this + + + align:start position:0% +value of this so if we assume that this +is much much less than one we can + + align:start position:0% +is much much less than one we can + + + align:start position:0% +is much much less than one we can +rewrite this in terms of a change in + + align:start position:0% +rewrite this in terms of a change in + + + align:start position:0% +rewrite this in terms of a change in +intensity so this would be the change in + + align:start position:0% +intensity so this would be the change in + + + align:start position:0% +intensity so this would be the change in +intensity in our image Delta I + + align:start position:0% +intensity in our image Delta I + + + align:start position:0% +intensity in our image Delta I +normalized to our initial intensity and + + align:start position:0% +normalized to our initial intensity and + + + align:start position:0% +normalized to our initial intensity and +that is going to be equal to 1 minus L / + + align:start position:0% +that is going to be equal to 1 minus L / + + + align:start position:0% +that is going to be equal to 1 minus L / +2 critical + + align:start position:0% +2 critical + + + align:start position:0% +2 critical +density squ integral of NE DL where in + + align:start position:0% +density squ integral of NE DL where in + + + align:start position:0% +density squ integral of NE DL where in +this last step I substituted out the + + align:start position:0% +this last step I substituted out the + + + align:start position:0% +this last step I substituted out the +refractive index for the expression that + + align:start position:0% +refractive index for the expression that + + + align:start position:0% +refractive index for the expression that +we had for any much less than n critical + + align:start position:0% +we had for any much less than n critical + + + align:start position:0% +we had for any much less than n critical +so again we've made an assumption that + + align:start position:0% +so again we've made an assumption that + + + align:start position:0% +so again we've made an assumption that +we have small intensity variations we've + + align:start position:0% +we have small intensity variations we've + + + align:start position:0% +we have small intensity variations we've +also made the assumption that NE is much + + align:start position:0% +also made the assumption that NE is much + + + align:start position:0% +also made the assumption that NE is much +much less than n critical so we can use + + align:start position:0% +much less than n critical so we can use + + + align:start position:0% +much less than n critical so we can use +this nice linear formula for + + align:start position:0% +this nice linear formula for + + + align:start position:0% +this nice linear formula for +um the refractive index of the plasma + + align:start position:0% +um the refractive index of the plasma + + + align:start position:0% +um the refractive index of the plasma +this simplifies everything so this is + + align:start position:0% +this simplifies everything so this is + + + align:start position:0% +this simplifies everything so this is +kind of like our final nice result here + + align:start position:0% +kind of like our final nice result here + + + align:start position:0% +kind of like our final nice result here +so for very small intensity variations + + align:start position:0% +so for very small intensity variations + + + align:start position:0% +so for very small intensity variations +you do indeed get an intensity variation + + align:start position:0% +you do indeed get an intensity variation + + + align:start position:0% +you do indeed get an intensity variation +which is proportional to one minus + + align:start position:0% +which is proportional to one minus + + + align:start position:0% +which is proportional to one minus +radiant squ of your electron density so + + align:start position:0% +radiant squ of your electron density so + + + align:start position:0% +radiant squ of your electron density so +using this formula where do we expect to + + align:start position:0% +using this formula where do we expect to + + + align:start position:0% +using this formula where do we expect to +have bright regions in our plasma so + + align:start position:0% +have bright regions in our plasma so + + + align:start position:0% +have bright regions in our plasma so +where where or sorry where do we expect + + align:start position:0% +where where or sorry where do we expect + + + align:start position:0% +where where or sorry where do we expect +to have bright regions in our interam + + align:start position:0% +to have bright regions in our interam + + + align:start position:0% +to have bright regions in our interam +what do they correspond + + align:start position:0% + + + + align:start position:0% + +to yeah anyone the bright regions would + + align:start position:0% +to yeah anyone the bright regions would + + + align:start position:0% +to yeah anyone the bright regions would +be places where the second term is + + align:start position:0% +be places where the second term is + + + align:start position:0% +be places where the second term is +small being small point of of the okay + + align:start position:0% +small being small point of of the okay + + + align:start position:0% +small being small point of of the okay +so only you where it's + + align:start position:0% + + + + align:start position:0% + +small like where it's negative and + + align:start position:0% +small like where it's negative and + + + align:start position:0% +small like where it's negative and +big like where it's negative and + + align:start position:0% +big like where it's negative and + + + align:start position:0% +big like where it's negative and +big right yeah exactly so the bright + + align:start position:0% +big right yeah exactly so the bright + + + align:start position:0% +big right yeah exactly so the bright +regions here are going to correspond to + + align:start position:0% +regions here are going to correspond to + + + align:start position:0% +regions here are going to correspond to +Minima in the + + align:start position:0% +Minima in the + + + align:start position:0% +Minima in the +density and the dark regions are kind + + align:start position:0% +density and the dark regions are kind + + + align:start position:0% +density and the dark regions are kind +kind of correspond to Ma + + align:start position:0% + + + + align:start position:0% + +that's because very roughly we think or + + align:start position:0% +that's because very roughly we think or + + + align:start position:0% +that's because very roughly we think or +when we think about what the plasma is + + align:start position:0% +when we think about what the plasma is + + + align:start position:0% +when we think about what the plasma is +doing we see that Minima in the electron + + align:start position:0% +doing we see that Minima in the electron + + + align:start position:0% +doing we see that Minima in the electron +density act as focusing lenses and + + align:start position:0% +density act as focusing lenses and + + + align:start position:0% +density act as focusing lenses and +Maxima act as diverging regions and so + + align:start position:0% +Maxima act as diverging regions and so + + + align:start position:0% +Maxima act as diverging regions and so +that's kind of what we saw around about + + align:start position:0% +that's kind of what we saw around about + + + align:start position:0% +that's kind of what we saw around about +here okay how did you get the um how did + + align:start position:0% +here okay how did you get the um how did + + + align:start position:0% +here okay how did you get the um how did +you get the I initial over idid + + align:start position:0% + + + + align:start position:0% + +form okay yeah it's it's not it's not + + align:start position:0% +form okay yeah it's it's not it's not + + + align:start position:0% +form okay yeah it's it's not it's not +obvious but you can go to book and see + + align:start position:0% +obvious but you can go to book and see + + + align:start position:0% +obvious but you can go to book and see +if you can follow derivation there but + + align:start position:0% +if you can follow derivation there but + + + align:start position:0% +if you can follow derivation there but +yeah there's there's a little bit of + + align:start position:0% +yeah there's there's a little bit of + + + align:start position:0% +yeah there's there's a little bit of +magic to do that step there the thing + + align:start position:0% +magic to do that step there the thing + + + align:start position:0% +magic to do that step there the thing +that you want to recognize is we're + + align:start position:0% +that you want to recognize is we're + + + align:start position:0% +that you want to recognize is we're +doing something that looks like it's got + + align:start position:0% +doing something that looks like it's got + + + align:start position:0% +doing something that looks like it's got +a Jacobian or something like that + + align:start position:0% +a Jacobian or something like that + + + align:start position:0% +a Jacobian or something like that +involved there so it all uh eventually + + align:start position:0% +involved there so it all uh eventually + + + align:start position:0% +involved there so it all uh eventually +ends up working out there's also a paper + + align:start position:0% +ends up working out there's also a paper + + + align:start position:0% +ends up working out there's also a paper +by kland that I'll mention later that's + + align:start position:0% +by kland that I'll mention later that's + + + align:start position:0% +by kland that I'll mention later that's +really good for this stuff if you want + + align:start position:0% +really good for this stuff if you want + + + align:start position:0% +really good for this stuff if you want +to see an alternative derivation yeah + + align:start position:0% +to see an alternative derivation yeah + + + align:start position:0% +to see an alternative derivation yeah +wondering how do we what is theise meing + + align:start position:0% +wondering how do we what is theise meing + + + align:start position:0% +wondering how do we what is theise meing +of the gradient of a line in the graded + + align:start position:0% +of the gradient of a line in the graded + + + align:start position:0% +of the gradient of a line in the graded +quantity is it like we're changing a + + align:start position:0% +quantity is it like we're changing a + + + align:start position:0% +quantity is it like we're changing a +integration by infal amount what does + + align:start position:0% +integration by infal amount what does + + + align:start position:0% +integration by infal amount what does +that + + align:start position:0% +that + + + align:start position:0% +that +mean + + align:start position:0% +mean + + + align:start position:0% +mean +um I mean mathematically you can just + + align:start position:0% +um I mean mathematically you can just + + + align:start position:0% +um I mean mathematically you can just +work it out right there's nothing wrong + + align:start position:0% +work it out right there's nothing wrong + + + align:start position:0% +work it out right there's nothing wrong +with this because for example if we are + + align:start position:0% +with this because for example if we are + + + align:start position:0% +with this because for example if we are +doing any of X Y and Z integrated DZ + + align:start position:0% +doing any of X Y and Z integrated DZ + + + align:start position:0% +doing any of X Y and Z integrated DZ +like that then you can still + + align:start position:0% +like that then you can still + + + align:start position:0% +like that then you can still +take the derivative of this you just + + align:start position:0% +take the derivative of this you just + + + align:start position:0% +take the derivative of this you just +won't have any Z components anymore + + align:start position:0% +won't have any Z components anymore + + + align:start position:0% +won't have any Z components anymore +you'll just have components in X and Y + + align:start position:0% +you'll just have components in X and Y + + + align:start position:0% +you'll just have components in X and Y +um in reality When I See This written + + align:start position:0% +um in reality When I See This written + + + align:start position:0% +um in reality When I See This written +down I often see people and I do the + + align:start position:0% +down I often see people and I do the + + + align:start position:0% +down I often see people and I do the +same thing who sort of sneakily move + + align:start position:0% +same thing who sort of sneakily move + + + align:start position:0% +same thing who sort of sneakily move +this integration sign to here and then + + align:start position:0% +this integration sign to here and then + + + align:start position:0% +this integration sign to here and then +it makes a little bit more sense because + + align:start position:0% +it makes a little bit more sense because + + + align:start position:0% +it makes a little bit more sense because +you're actually looking for each step DL + + align:start position:0% +you're actually looking for each step DL + + + align:start position:0% +you're actually looking for each step DL +that the ray goes through the plasma you + + align:start position:0% +that the ray goes through the plasma you + + + align:start position:0% +that the ray goes through the plasma you +look at what the local density gradient + + align:start position:0% +look at what the local density gradient + + + align:start position:0% +look at what the local density gradient +is and I think these two things are + + align:start position:0% +is and I think these two things are + + + align:start position:0% +is and I think these two things are +different kind of obviously um but they + + align:start position:0% +different kind of obviously um but they + + + align:start position:0% +different kind of obviously um but they +are pretty close for thin plasmas and + + align:start position:0% +are pretty close for thin plasmas and + + + align:start position:0% +are pretty close for thin plasmas and +what most of the time people are doing + + align:start position:0% +what most of the time people are doing + + + align:start position:0% +what most of the time people are doing +is making approximations that the width + + align:start position:0% +is making approximations that the width + + + align:start position:0% +is making approximations that the width +of this plasma which might be a or + + align:start position:0% +of this plasma which might be a or + + + align:start position:0% +of this plasma which might be a or +something like that is much much less + + align:start position:0% +something like that is much much less + + + align:start position:0% +something like that is much much less +than L um so this is effectively + + align:start position:0% +than L um so this is effectively + + + align:start position:0% +than L um so this is effectively +assuming that the actual path that the + + align:start position:0% +assuming that the actual path that the + + + align:start position:0% +assuming that the actual path that the +ray takes through the plasma is + + align:start position:0% +ray takes through the plasma is + + + align:start position:0% +ray takes through the plasma is +unimportant we only just care about what + + align:start position:0% +unimportant we only just care about what + + + align:start position:0% +unimportant we only just care about what +path it takes through free space + + align:start position:0% +path it takes through free space + + + align:start position:0% +path it takes through free space +affluence which is be in the straight + + align:start position:0% +affluence which is be in the straight + + + align:start position:0% +affluence which is be in the straight +line if you don't have this condition + + align:start position:0% +line if you don't have this condition + + + align:start position:0% +line if you don't have this condition +you actually end up in the costic ra + + align:start position:0% +you actually end up in the costic ra + + + align:start position:0% +you actually end up in the costic ra +more easily and again I'll point you + + align:start position:0% +more easily and again I'll point you + + + align:start position:0% +more easily and again I'll point you +some references later which talk about + + align:start position:0% +some references later which talk about + + + align:start position:0% +some references later which talk about +this in a bit more detail for the for + + align:start position:0% +this in a bit more detail for the for + + + align:start position:0% +this in a bit more detail for the for +the in the case where the thickness of + + align:start position:0% +the in the case where the thickness of + + + align:start position:0% +the in the case where the thickness of +the plasma it is much less than the + + align:start position:0% +the plasma it is much less than the + + + align:start position:0% +the plasma it is much less than the +distance between the plasma and the + + align:start position:0% +distance between the plasma and the + + + align:start position:0% +distance between the plasma and the +detector it doesn't really matter which + + align:start position:0% +detector it doesn't really matter which + + + align:start position:0% +detector it doesn't really matter which +way around you do this + + align:start position:0% +way around you do this + + + align:start position:0% +way around you do this +operation yeah good question yeah seen + + align:start position:0% +operation yeah good question yeah seen + + + align:start position:0% +operation yeah good question yeah seen +the regime or sort of saying that the P + + align:start position:0% +the regime or sort of saying that the P + + + align:start position:0% +the regime or sort of saying that the P +probably doesn't matter isn't that just + + align:start position:0% +probably doesn't matter isn't that just + + + align:start position:0% +probably doesn't matter isn't that just +like the + + align:start position:0% +like the + + + align:start position:0% +like the +sh yeah and indeed this effect crops up + + align:start position:0% +sh yeah and indeed this effect crops up + + + align:start position:0% +sh yeah and indeed this effect crops up +in schen as well but in schen the bigger + + align:start position:0% +in schen as well but in schen the bigger + + + align:start position:0% +in schen as well but in schen the bigger +effect you get is by putting the stop + + align:start position:0% +effect you get is by putting the stop + + + align:start position:0% +effect you get is by putting the stop +and blocking out the Reds but you will + + align:start position:0% +and blocking out the Reds but you will + + + align:start position:0% +and blocking out the Reds but you will +have shog effects inside your schan + + align:start position:0% +have shog effects inside your schan + + + align:start position:0% +have shog effects inside your schan +Imaging system too okay so yeah I just + + align:start position:0% +Imaging system too okay so yeah I just + + + align:start position:0% +Imaging system too okay so yeah I just +introduced the schan first and now we + + align:start position:0% +introduced the schan first and now we + + + align:start position:0% +introduced the schan first and now we +have theography but these are both + + align:start position:0% +have theography but these are both + + + align:start position:0% +have theography but these are both +present here and they're also present in + + align:start position:0% +present here and they're also present in + + + align:start position:0% +present here and they're also present in +some inry we about but in each of these + + align:start position:0% +some inry we about but in each of these + + + align:start position:0% +some inry we about but in each of these +there's like something that causes the + + align:start position:0% +there's like something that causes the + + + align:start position:0% +there's like something that causes the +biggest intensity modulations thean is + + align:start position:0% +biggest intensity modulations thean is + + + align:start position:0% +biggest intensity modulations thean is +the schan stop clearly but here again + + align:start position:0% +the schan stop clearly but here again + + + align:start position:0% +the schan stop clearly but here again +we're only looking in this regim small + + align:start position:0% +we're only looking in this regim small + + + align:start position:0% +we're only looking in this regim small +intensity modulation for moment um but + + align:start position:0% +intensity modulation for moment um but + + + align:start position:0% +intensity modulation for moment um but +without the sh and stop this is the + + align:start position:0% +without the sh and stop this is the + + + align:start position:0% +without the sh and stop this is the +effect that shows up + + align:start position:0% + + + + align:start position:0% + +our signal is proportional to thetion + + align:start position:0% +our signal is proportional to thetion + + + align:start position:0% +our signal is proportional to thetion +density and so why is it that maximum + + align:start position:0% +density and so why is it that maximum + + + align:start position:0% +density and so why is it that maximum +minimum of the signal correspond to + + align:start position:0% +minimum of the signal correspond to + + + align:start position:0% +minimum of the signal correspond to +maximum minimum of the density rather + + align:start position:0% +maximum minimum of the density rather + + + align:start position:0% +maximum minimum of the density rather +than Maxim minimum of the density + + align:start position:0% + + + + align:start position:0% + +gradient yeah I see what you're saying I + + align:start position:0% +gradient yeah I see what you're saying I + + + align:start position:0% +gradient yeah I see what you're saying I +think it's because it's thean of the + + align:start position:0% +think it's because it's thean of the + + + align:start position:0% +think it's because it's thean of the +line + + align:start position:0% +line + + + align:start position:0% +line +in Asos + + align:start position:0% +in Asos + + + align:start position:0% +in Asos +to or like the integration over space + + align:start position:0% +to or like the integration over space + + + align:start position:0% +to or like the integration over space +brings you back a level yeah I'll I'll + + align:start position:0% +brings you back a level yeah I'll I'll + + + align:start position:0% +brings you back a level yeah I'll I'll +have a look at that and check I do see + + align:start position:0% +have a look at that and check I do see + + + align:start position:0% +have a look at that and check I do see +what you're saying I see what you're + + align:start position:0% +what you're saying I see what you're + + + align:start position:0% +what you're saying I see what you're +saying and I don't know what the + + align:start position:0% +saying and I don't know what the + + + align:start position:0% +saying and I don't know what the +resolution is right at the moment but + + align:start position:0% +resolution is right at the moment but + + + align:start position:0% +resolution is right at the moment but +yeah I'll have a look and see if I can + + align:start position:0% +yeah I'll have a look and see if I can + + + align:start position:0% +yeah I'll have a look and see if I can +work that out thank you cool so again + + align:start position:0% +work that out thank you cool so again + + + align:start position:0% +work that out thank you cool so again +this looks really nice because it looks + + align:start position:0% +this looks really nice because it looks + + + align:start position:0% +this looks really nice because it looks +like you can get out the second + + align:start position:0% +like you can get out the second + + + align:start position:0% +like you can get out the second +derivative of the density and then maybe + + align:start position:0% +derivative of the density and then maybe + + + align:start position:0% +derivative of the density and then maybe +you could like double integrate that and + + align:start position:0% +you could like double integrate that and + + + align:start position:0% +you could like double integrate that and +you could get out the actual line + + align:start position:0% +you could get out the actual line + + + align:start position:0% +you could get out the actual line +integrated electron density but in + + align:start position:0% +integrated electron density but in + + + align:start position:0% +integrated electron density but in +reality the assumptions we've had to + + align:start position:0% +reality the assumptions we've had to + + + align:start position:0% +reality the assumptions we've had to +make to get here mean this is really + + align:start position:0% +make to get here mean this is really + + + align:start position:0% +make to get here mean this is really +hard because the actual signal term we + + align:start position:0% +hard because the actual signal term we + + + align:start position:0% +hard because the actual signal term we +have assumed is much much smaller than + + align:start position:0% +have assumed is much much smaller than + + + align:start position:0% +have assumed is much much smaller than +one which means that it's really really + + align:start position:0% +one which means that it's really really + + + align:start position:0% +one which means that it's really really +hard to + + align:start position:0% + + + + align:start position:0% + +measure so for any realistic system with + + align:start position:0% +measure so for any realistic system with + + + align:start position:0% +measure so for any realistic system with +a realistic signal to noise we don't + + align:start position:0% +a realistic signal to noise we don't + + + align:start position:0% +a realistic signal to noise we don't +want to have this limitation we don't + + align:start position:0% +want to have this limitation we don't + + + align:start position:0% +want to have this limitation we don't +want to be working at position one or + + align:start position:0% +want to be working at position one or + + + align:start position:0% +want to be working at position one or +even position two we're actually get the + + align:start position:0% +even position two we're actually get the + + + align:start position:0% +even position two we're actually get the +best signal when we go to position three + + align:start position:0% +best signal when we go to position three + + + align:start position:0% +best signal when we go to position three +where all of this no longer applies and + + align:start position:0% +where all of this no longer applies and + + + align:start position:0% +where all of this no longer applies and +we can no longer get this nice result + + align:start position:0% +we can no longer get this nice result + + + align:start position:0% +we can no longer get this nice result +and this is what I'm saying where you + + align:start position:0% +and this is what I'm saying where you + + + align:start position:0% +and this is what I'm saying where you +will find people saying chog graphy is + + align:start position:0% +will find people saying chog graphy is + + + align:start position:0% +will find people saying chog graphy is +proportional to the second derivative of + + align:start position:0% +proportional to the second derivative of + + + align:start position:0% +proportional to the second derivative of +the electron density and that's sort of + + align:start position:0% +the electron density and that's sort of + + + align:start position:0% +the electron density and that's sort of +true but I've never seen anyone do it + + align:start position:0% +true but I've never seen anyone do it + + + align:start position:0% +true but I've never seen anyone do it +like it's not actually possible to do + + align:start position:0% +like it's not actually possible to do + + + align:start position:0% +like it's not actually possible to do +that measurement in a meaningful way you + + align:start position:0% +that measurement in a meaningful way you + + + align:start position:0% +that measurement in a meaningful way you +have to work in a regime where you can + + align:start position:0% +have to work in a regime where you can + + + align:start position:0% +have to work in a regime where you can +actually measure the modulation and I'll + + align:start position:0% +actually measure the modulation and I'll + + + align:start position:0% +actually measure the modulation and I'll +show you some example pictures of SCH an + + align:start position:0% +show you some example pictures of SCH an + + + align:start position:0% +show you some example pictures of SCH an +chonograph towards the end of this + + align:start position:0% +chonograph towards the end of this + + + align:start position:0% +chonograph towards the end of this +lecture so you get an idea of what it + + align:start position:0% +lecture so you get an idea of what it + + + align:start position:0% +lecture so you get an idea of what it +looks like inas + + align:start position:0% + + + + align:start position:0% + +okay I think I kind of said a lot of + + align:start position:0% +okay I think I kind of said a lot of + + + align:start position:0% +okay I think I kind of said a lot of +this already if we end up in this regime + + align:start position:0% +this already if we end up in this regime + + + align:start position:0% +this already if we end up in this regime +here where we have these cor + + align:start position:0% +here where we have these cor + + + align:start position:0% +here where we have these cor +sticks we've clearly lost information we + + align:start position:0% +sticks we've clearly lost information we + + + align:start position:0% +sticks we've clearly lost information we +can no longer do this mapping here + + align:start position:0% +can no longer do this mapping here + + + align:start position:0% +can no longer do this mapping here +because it's no longer unique we've got + + align:start position:0% +because it's no longer unique we've got + + + align:start position:0% +because it's no longer unique we've got +raised Crossing so different bits of X + + align:start position:0% +raised Crossing so different bits of X + + + align:start position:0% +raised Crossing so different bits of X +Prime and Y Prime are mapping onto or + + align:start position:0% +Prime and Y Prime are mapping onto or + + + align:start position:0% +Prime and Y Prime are mapping onto or +one place in X Prime y Prime might map + + align:start position:0% +one place in X Prime y Prime might map + + + align:start position:0% +one place in X Prime y Prime might map +onto multiple X and Y and so we can't do + + align:start position:0% +onto multiple X and Y and so we can't do + + + align:start position:0% +onto multiple X and Y and so we can't do +this simple uh thing and it's kind of + + align:start position:0% +this simple uh thing and it's kind of + + + align:start position:0% +this simple uh thing and it's kind of +obvious actually that you'll be losing + + align:start position:0% +obvious actually that you'll be losing + + + align:start position:0% +obvious actually that you'll be losing +uh information and even a more advanced + + align:start position:0% +uh information and even a more advanced + + + align:start position:0% +uh information and even a more advanced +technique isn't going to be able to do + + align:start position:0% +technique isn't going to be able to do + + + align:start position:0% +technique isn't going to be able to do +the Reconstruction so I want to talk + + align:start position:0% +the Reconstruction so I want to talk + + + align:start position:0% +the Reconstruction so I want to talk +just now a little bit about some of + + align:start position:0% +just now a little bit about some of + + + align:start position:0% +just now a little bit about some of +these Advanced reconstruction techniques + + align:start position:0% +these Advanced reconstruction techniques + + + align:start position:0% +these Advanced reconstruction techniques +which go beyond this and then I'll show + + align:start position:0% +which go beyond this and then I'll show + + + align:start position:0% +which go beyond this and then I'll show +these examples + + align:start position:0% + + + + align:start position:0% + +so the first paper I've seen that really + + align:start position:0% +so the first paper I've seen that really + + + align:start position:0% +so the first paper I've seen that really +tackles this very nicely is + + align:start position:0% +tackles this very nicely is + + + align:start position:0% +tackles this very nicely is +candile in + + align:start position:0% +candile in + + + align:start position:0% +candile in +RSI + + align:start position:0% + + + + align:start position:0% + +2012 so cand points out pretty quickly + + align:start position:0% +2012 so cand points out pretty quickly + + + align:start position:0% +2012 so cand points out pretty quickly +that + + align:start position:0% + + + + align:start position:0% + +chirography has a direct equivalent to + + align:start position:0% +chirography has a direct equivalent to + + + align:start position:0% +chirography has a direct equivalent to +proton radiography so mathematically + + align:start position:0% +proton radiography so mathematically + + + align:start position:0% +proton radiography so mathematically +they both deal with the same quantities + + align:start position:0% +they both deal with the same quantities + + + align:start position:0% +they both deal with the same quantities +which is a sort of deflection potential + + align:start position:0% +which is a sort of deflection potential + + + align:start position:0% +which is a sort of deflection potential +in proton radiography this deflection + + align:start position:0% +in proton radiography this deflection + + + align:start position:0% +in proton radiography this deflection +potential is to do with electric and + + align:start position:0% +potential is to do with electric and + + + align:start position:0% +potential is to do with electric and +magnetic fields and we'll get on to + + align:start position:0% +magnetic fields and we'll get on to + + + align:start position:0% +magnetic fields and we'll get on to +proton radiography later and in shog + + align:start position:0% +proton radiography later and in shog + + + align:start position:0% +proton radiography later and in shog +graphy the deflection potential is to do + + align:start position:0% +graphy the deflection potential is to do + + + align:start position:0% +graphy the deflection potential is to do +with density radius but once you work in + + align:start position:0% +with density radius but once you work in + + + align:start position:0% +with density radius but once you work in +terms of this deflection potential and + + align:start position:0% +terms of this deflection potential and + + + align:start position:0% +terms of this deflection potential and +forget where it came from you get + + align:start position:0% +forget where it came from you get + + + align:start position:0% +forget where it came from you get +exactly the same results mathematically + + align:start position:0% +exactly the same results mathematically + + + align:start position:0% +exactly the same results mathematically +and he has this nice geometric + + align:start position:0% +and he has this nice geometric + + + align:start position:0% +and he has this nice geometric +approach and so if you found the + + align:start position:0% +approach and so if you found the + + + align:start position:0% +approach and so if you found the +derivation I just did not very very + + align:start position:0% +derivation I just did not very very + + + align:start position:0% +derivation I just did not very very +convincing you can go and have a look at + + align:start position:0% +convincing you can go and have a look at + + + align:start position:0% +convincing you can go and have a look at +this it's a little bit more rigorous and + + align:start position:0% +this it's a little bit more rigorous and + + + align:start position:0% +this it's a little bit more rigorous and +also he then extends it into the CTIC + + align:start position:0% +also he then extends it into the CTIC + + + align:start position:0% +also he then extends it into the CTIC +regime and Beyond and shows what you + + align:start position:0% +regime and Beyond and shows what you + + + align:start position:0% +regime and Beyond and shows what you +would expect to get from a plasma uh + + align:start position:0% +would expect to get from a plasma uh + + + align:start position:0% +would expect to get from a plasma uh +where you have Co stics so this is nice + + align:start position:0% +where you have Co stics so this is nice + + + align:start position:0% +where you have Co stics so this is nice +um but he still doesn't really tell you + + align:start position:0% +um but he still doesn't really tell you + + + align:start position:0% +um but he still doesn't really tell you +how to analyze it it's it's really + + align:start position:0% +how to analyze it it's it's really + + + align:start position:0% +how to analyze it it's it's really +talking about the problem where you go + + align:start position:0% +talking about the problem where you go + + + align:start position:0% +talking about the problem where you go +from knowing the density of the plasma + + align:start position:0% +from knowing the density of the plasma + + + align:start position:0% +from knowing the density of the plasma +to predicting what you're going to get + + align:start position:0% +to predicting what you're going to get + + + align:start position:0% +to predicting what you're going to get +out going the opposite direction to + + align:start position:0% +out going the opposite direction to + + + align:start position:0% +out going the opposite direction to +going from your intensity variations to + + align:start position:0% +going from your intensity variations to + + + align:start position:0% +going from your intensity variations to +the density uh isn't particularly well + + align:start position:0% +the density uh isn't particularly well + + + align:start position:0% +the density uh isn't particularly well +about so this is + + align:start position:0% +about so this is + + + align:start position:0% +about so this is +what some people call the forward + + align:start position:0% + + + + align:start position:0% + +problem and the forward problem is going + + align:start position:0% +problem and the forward problem is going + + + align:start position:0% +problem and the forward problem is going +from NE of X Y and Z to intensity on + + align:start position:0% +from NE of X Y and Z to intensity on + + + align:start position:0% +from NE of X Y and Z to intensity on +your detector in X Prime and Y Prime + + align:start position:0% +your detector in X Prime and Y Prime + + + align:start position:0% +your detector in X Prime and Y Prime +useful but not exactly the + + align:start position:0% +useful but not exactly the + + + align:start position:0% +useful but not exactly the +solution so then in 2017 there were two + + align:start position:0% +solution so then in 2017 there were two + + + align:start position:0% +solution so then in 2017 there were two +almost competing papers that came out + + align:start position:0% +almost competing papers that came out + + + align:start position:0% +almost competing papers that came out +about this there was a paper by + + align:start position:0% +about this there was a paper by + + + align:start position:0% +about this there was a paper by +cassim asile in physical review e + + align:start position:0% +cassim asile in physical review e + + + align:start position:0% +cassim asile in physical review e +2017 what cassine did is he tried to + + align:start position:0% +2017 what cassine did is he tried to + + + align:start position:0% +2017 what cassine did is he tried to +reconstruct this deflection potential + + align:start position:0% +reconstruct this deflection potential + + + align:start position:0% +reconstruct this deflection potential +that cin would come + + align:start position:0% + + + + align:start position:0% + +here and he did this using uh a + + align:start position:0% +here and he did this using uh a + + + align:start position:0% +here and he did this using uh a +technique that was borrowed uh from some + + align:start position:0% +technique that was borrowed uh from some + + + align:start position:0% +technique that was borrowed uh from some +would say computer Graphics or at least + + align:start position:0% +would say computer Graphics or at least + + + align:start position:0% +would say computer Graphics or at least +some fields of Applied Mathematics uh + + align:start position:0% +some fields of Applied Mathematics uh + + + align:start position:0% +some fields of Applied Mathematics uh +which used a aoid diagram has anyone + + align:start position:0% +which used a aoid diagram has anyone + + + align:start position:0% +which used a aoid diagram has anyone +come across borono diagrams + + align:start position:0% +come across borono diagrams + + + align:start position:0% +come across borono diagrams +before huge in robotics sorry they're + + align:start position:0% +before huge in robotics sorry they're + + + align:start position:0% +before huge in robotics sorry they're +huge in robotics okay cool right so + + align:start position:0% +huge in robotics okay cool right so + + + align:start position:0% +huge in robotics okay cool right so +there's like they basically I think this + + align:start position:0% +there's like they basically I think this + + + align:start position:0% +there's like they basically I think this +worked well because they took some work + + align:start position:0% +worked well because they took some work + + + align:start position:0% +worked well because they took some work +that other people been doing in + + align:start position:0% +that other people been doing in + + + align:start position:0% +that other people been doing in +different F and applied it here so aoid + + align:start position:0% +different F and applied it here so aoid + + + align:start position:0% +different F and applied it here so aoid +diagram haha please don't shout me if I + + align:start position:0% +diagram haha please don't shout me if I + + + align:start position:0% +diagram haha please don't shout me if I +get this wrong is roughly if you have a + + align:start position:0% +get this wrong is roughly if you have a + + + align:start position:0% +get this wrong is roughly if you have a +series of points which are randomly + + align:start position:0% +series of points which are randomly + + + align:start position:0% +series of points which are randomly +distributed + + align:start position:0% +distributed + + + align:start position:0% +distributed +how do you draw quadrilaterals around + + align:start position:0% +how do you draw quadrilaterals around + + + align:start position:0% +how do you draw quadrilaterals around +them such that every Point inside the + + align:start position:0% +them such that every Point inside the + + + align:start position:0% +them such that every Point inside the +quadrilateral is closest to this point + + align:start position:0% +quadrilateral is closest to this point + + + align:start position:0% +quadrilateral is closest to this point +and not to any of the other points so + + align:start position:0% +and not to any of the other points so + + + align:start position:0% +and not to any of the other points so +it's a way of tiling up a + + align:start position:0% + + + + align:start position:0% + +space and from this you can imagine + + align:start position:0% +space and from this you can imagine + + + align:start position:0% +space and from this you can imagine +these uh these tiles that youve produced + + align:start position:0% +these uh these tiles that youve produced + + + align:start position:0% +these uh these tiles that youve produced +in your um chog graphy can then be + + align:start position:0% +in your um chog graphy can then be + + + align:start position:0% +in your um chog graphy can then be +related back to a more uniform grid of + + align:start position:0% +related back to a more uniform grid of + + + align:start position:0% +related back to a more uniform grid of +tiles which all have the same shape and + + align:start position:0% +tiles which all have the same shape and + + + align:start position:0% +tiles which all have the same shape and +the same uh intensity which is your + + align:start position:0% +the same uh intensity which is your + + + align:start position:0% +the same uh intensity which is your +intensity beforehand and this is your + + align:start position:0% +intensity beforehand and this is your + + + align:start position:0% +intensity beforehand and this is your +intensity at the detector again this is + + align:start position:0% +intensity at the detector again this is + + + align:start position:0% +intensity at the detector again this is +just a very handwavy sketch of what they + + align:start position:0% +just a very handwavy sketch of what they + + + align:start position:0% +just a very handwavy sketch of what they +did they came up with an algorithm to do + + align:start position:0% +did they came up with an algorithm to do + + + align:start position:0% +did they came up with an algorithm to do +this and this enabled them to do the + + align:start position:0% +this and this enabled them to do the + + + align:start position:0% +this and this enabled them to do the +inverse problem which is intensity of + + align:start position:0% +inverse problem which is intensity of + + + align:start position:0% +inverse problem which is intensity of +our detector in X Prime y Prime going + + align:start position:0% +our detector in X Prime y Prime going + + + align:start position:0% +our detector in X Prime y Prime going +back towards density next y see and as + + align:start position:0% +back towards density next y see and as + + + align:start position:0% +back towards density next y see and as +you discussed before this is an illposed + + align:start position:0% +you discussed before this is an illposed + + + align:start position:0% +you discussed before this is an illposed +problem there are a large family of + + align:start position:0% +problem there are a large family of + + + align:start position:0% +problem there are a large family of +possible density structures that produce + + align:start position:0% +possible density structures that produce + + + align:start position:0% +possible density structures that produce +the same intensity but this roro diagram + + align:start position:0% +the same intensity but this roro diagram + + + align:start position:0% +the same intensity but this roro diagram +is making conservative assumptions about + + align:start position:0% +is making conservative assumptions about + + + align:start position:0% +is making conservative assumptions about +where light has come from in order to be + + align:start position:0% +where light has come from in order to be + + + align:start position:0% +where light has come from in order to be +able to put stuff + + align:start position:0% +able to put stuff + + + align:start position:0% +able to put stuff +back and almost exactly pling time + + align:start position:0% +back and almost exactly pling time + + + align:start position:0% +back and almost exactly pling time +but both groups are on yes so would this + + align:start position:0% +but both groups are on yes so would this + + + align:start position:0% +but both groups are on yes so would this +be applicable to shooting an array of + + align:start position:0% +be applicable to shooting an array of + + + align:start position:0% +be applicable to shooting an array of +blazers should G oh so no one does that + + align:start position:0% +blazers should G oh so no one does that + + + align:start position:0% +blazers should G oh so no one does that +but they should so they didn't proton + + align:start position:0% +but they should so they didn't proton + + + align:start position:0% +but they should so they didn't proton +radiography in the early days they + + align:start position:0% +radiography in the early days they + + + align:start position:0% +radiography in the early days they +actually had like little beamlets and + + align:start position:0% +actually had like little beamlets and + + + align:start position:0% +actually had like little beamlets and +then you can uniquely work out where + + align:start position:0% +then you can uniquely work out where + + + align:start position:0% +then you can uniquely work out where +each beamlet is deflected but of course + + align:start position:0% +each beamlet is deflected but of course + + + align:start position:0% +each beamlet is deflected but of course +you only get like n beamlets of points + + align:start position:0% +you only get like n beamlets of points + + + align:start position:0% +you only get like n beamlets of points +of data and it's like it doesn't look + + align:start position:0% +of data and it's like it doesn't look + + + align:start position:0% +of data and it's like it doesn't look +pretty you can't put in nature that sort + + align:start position:0% +pretty you can't put in nature that sort + + + align:start position:0% +pretty you can't put in nature that sort +of thing so people move very quickly + + align:start position:0% +of thing so people move very quickly + + + align:start position:0% +of thing so people move very quickly +away from that technique so now we have + + align:start position:0% +away from that technique so now we have + + + align:start position:0% +away from that technique so now we have +data that's impossible to analyze it's + + align:start position:0% +data that's impossible to analyze it's + + + align:start position:0% +data that's impossible to analyze it's +very beautiful whereas we used to have + + align:start position:0% +very beautiful whereas we used to have + + + align:start position:0% +very beautiful whereas we used to have +data that was entirely analyzable but + + align:start position:0% +data that was entirely analyzable but + + + align:start position:0% +data that was entirely analyzable but +not very beautiful so I have opinions + + align:start position:0% +not very beautiful so I have opinions + + + align:start position:0% +not very beautiful so I have opinions +this abely just a finite number of like + + align:start position:0% +this abely just a finite number of like + + + align:start position:0% +this abely just a finite number of like +r no I mean this this is entirely to do + + align:start position:0% +r no I mean this this is entirely to do + + + align:start position:0% +r no I mean this this is entirely to do +with um this is not to do with the + + align:start position:0% +with um this is not to do with the + + + align:start position:0% +with um this is not to do with the +finite number of R this is still to do + + align:start position:0% +finite number of R this is still to do + + + align:start position:0% +finite number of R this is still to do +with our nice like initially uniform + + align:start position:0% +with our nice like initially uniform + + + align:start position:0% +with our nice like initially uniform +beam it's just the way that we segment + + align:start position:0% +beam it's just the way that we segment + + + align:start position:0% +beam it's just the way that we segment +up the final image these dots don't + + align:start position:0% +up the final image these dots don't + + + align:start position:0% +up the final image these dots don't +really exist you actually in reality + + align:start position:0% +really exist you actually in reality + + + align:start position:0% +really exist you actually in reality +you're trying to + + align:start position:0% +you're trying to + + + align:start position:0% +you're trying to +find this is where I'm probably going to + + align:start position:0% +find this is where I'm probably going to + + + align:start position:0% +find this is where I'm probably going to +get it wrong you're trying to find + + align:start position:0% +get it wrong you're trying to find + + + align:start position:0% +get it wrong you're trying to find +Regions which contain the same intensity + + align:start position:0% +Regions which contain the same intensity + + + align:start position:0% +Regions which contain the same intensity +as one of these initial squares and + + align:start position:0% +as one of these initial squares and + + + align:start position:0% +as one of these initial squares and +you're trying to sort of tile them + + align:start position:0% +you're trying to sort of tile them + + + align:start position:0% +you're trying to sort of tile them +together in such a way that you don't + + align:start position:0% +together in such a way that you don't + + + align:start position:0% +together in such a way that you don't +have to have something that looks like a + + align:start position:0% +have to have something that looks like a + + + align:start position:0% +have to have something that looks like a +congressional district right + + align:start position:0% +congressional district right + + + align:start position:0% +congressional district right +where okay because that this is silly + + align:start position:0% +where okay because that this is silly + + + align:start position:0% +where okay because that this is silly +like that's unlikely to happen so we're + + align:start position:0% +like that's unlikely to happen so we're + + + align:start position:0% +like that's unlikely to happen so we're +trying to this is you know you could + + align:start position:0% +trying to this is you know you could + + + align:start position:0% +trying to this is you know you could +maybe use this algorithm to sort out a + + align:start position:0% +maybe use this algorithm to sort out a + + + align:start position:0% +maybe use this algorithm to sort out a +lot of problems in this + + align:start position:0% +lot of problems in this + + + align:start position:0% +lot of problems in this +anyway so at the same time bot uh was + + align:start position:0% +anyway so at the same time bot uh was + + + align:start position:0% +anyway so at the same time bot uh was +working on an algorithm that ended up + + align:start position:0% +working on an algorithm that ended up + + + align:start position:0% +working on an algorithm that ended up +doing the same thing and this is in jpp + + align:start position:0% +doing the same thing and this is in jpp + + + align:start position:0% +doing the same thing and this is in jpp +in + + align:start position:0% +in + + + align:start position:0% +in +2017 this paper is something like 120 + + align:start position:0% +2017 this paper is something like 120 + + + align:start position:0% +2017 this paper is something like 120 +pages long very much helps to have your + + align:start position:0% +pages long very much helps to have your + + + align:start position:0% +pages long very much helps to have your +decent advisor be the Ed for and chief + + align:start position:0% +decent advisor be the Ed for and chief + + + align:start position:0% +decent advisor be the Ed for and chief +of jvp if you want publ paper L and they + + align:start position:0% +of jvp if you want publ paper L and they + + + align:start position:0% +of jvp if you want publ paper L and they +use a very interesting technique called + + align:start position:0% +use a very interesting technique called + + + align:start position:0% +use a very interesting technique called +the I'm probably G to say this WR and I + + align:start position:0% +the I'm probably G to say this WR and I + + + align:start position:0% +the I'm probably G to say this WR and I +certainly hand all the Accents in my + + align:start position:0% +certainly hand all the Accents in my + + + align:start position:0% +certainly hand all the Accents in my +notes Here M + + align:start position:0% +notes Here M + + + align:start position:0% +notes Here M +and optimal + + align:start position:0% +and optimal + + + align:start position:0% +and optimal +transport this optimal transport + + align:start position:0% +transport this optimal transport + + + align:start position:0% +transport this optimal transport +algorithm had actually won someone the + + align:start position:0% +algorithm had actually won someone the + + + align:start position:0% +algorithm had actually won someone the +fields medal only a few years before + + align:start position:0% +fields medal only a few years before + + + align:start position:0% +fields medal only a few years before +Cedric vanan wears his incredibly huge B + + align:start position:0% +Cedric vanan wears his incredibly huge B + + + align:start position:0% +Cedric vanan wears his incredibly huge B +ties and he has a wonderful book called + + align:start position:0% +ties and he has a wonderful book called + + + align:start position:0% +ties and he has a wonderful book called +The Life of the theorem where he + + align:start position:0% +The Life of the theorem where he + + + align:start position:0% +The Life of the theorem where he +discusses how gra cedri but so this + + align:start position:0% +discusses how gra cedri but so this + + + align:start position:0% +discusses how gra cedri but so this +algorithm was derived not at all to do + + align:start position:0% +algorithm was derived not at all to do + + + align:start position:0% +algorithm was derived not at all to do +with proton radiography but it is to do + + align:start position:0% +with proton radiography but it is to do + + + align:start position:0% +with proton radiography but it is to do +with how we how what is the most like + + align:start position:0% +with how we how what is the most like + + + align:start position:0% +with how we how what is the most like +conservative way to map one function + + align:start position:0% +conservative way to map one function + + + align:start position:0% +conservative way to map one function +into another function like this and once + + align:start position:0% +into another function like this and once + + + align:start position:0% +into another function like this and once +you derive that you can then put it back + + align:start position:0% +you derive that you can then put it back + + + align:start position:0% +you derive that you can then put it back +where you started with so this also + + align:start position:0% +where you started with so this also + + + align:start position:0% +where you started with so this also +enables you to do this same inverse + + align:start position:0% +enables you to do this same inverse + + + align:start position:0% +enables you to do this same inverse +problem like this and I'm not even gonna + + align:start position:0% +problem like this and I'm not even gonna + + + align:start position:0% +problem like this and I'm not even gonna +slightly go through my guess at what the + + align:start position:0% +slightly go through my guess at what the + + + align:start position:0% +slightly go through my guess at what the +mor amp equation does because I don't + + align:start position:0% +mor amp equation does because I don't + + + align:start position:0% +mor amp equation does because I don't +have um but it seems to work they give + + align:start position:0% +have um but it seems to work they give + + + align:start position:0% +have um but it seems to work they give +similar results turns out this is much + + align:start position:0% +similar results turns out this is much + + + align:start position:0% +similar results turns out this is much +faster I think most people + + align:start position:0% +faster I think most people + + + align:start position:0% +faster I think most people +use some version of this at the moment + + align:start position:0% +use some version of this at the moment + + + align:start position:0% +use some version of this at the moment +um but this one is maybe it easier to + + align:start position:0% +um but this one is maybe it easier to + + + align:start position:0% +um but this one is maybe it easier to +understand um so both of these give sort + + align:start position:0% +understand um so both of these give sort + + + align:start position:0% +understand um so both of these give sort +of similar results with slightly + + align:start position:0% +of similar results with slightly + + + align:start position:0% +of similar results with slightly +different techniques and I think in the + + align:start position:0% +different techniques and I think in the + + + align:start position:0% +different techniques and I think in the +end cassim wrote a code based on bot's + + align:start position:0% +end cassim wrote a code based on bot's + + + align:start position:0% +end cassim wrote a code based on bot's +paper that was faster than what bot had + + align:start position:0% +paper that was faster than what bot had + + + align:start position:0% +paper that was faster than what bot had +done so I think people have converged on + + align:start position:0% +done so I think people have converged on + + + align:start position:0% +done so I think people have converged on +using something to do with this and + + align:start position:0% +using something to do with this and + + + align:start position:0% +using something to do with this and +again these techniques were mostly uh + + align:start position:0% +again these techniques were mostly uh + + + align:start position:0% +again these techniques were mostly uh +invented for proton radiography but now + + align:start position:0% +invented for proton radiography but now + + + align:start position:0% +invented for proton radiography but now +uh as we said the mathematics is the + + align:start position:0% +uh as we said the mathematics is the + + + align:start position:0% +uh as we said the mathematics is the +same for phography I have not seen + + align:start position:0% +same for phography I have not seen + + + align:start position:0% +same for phography I have not seen +anyone use either technique to properly + + align:start position:0% +anyone use either technique to properly + + + align:start position:0% +anyone use either technique to properly +analyze phography should be possible yes + + align:start position:0% +analyze phography should be possible yes + + + align:start position:0% +analyze phography should be possible yes +how does this problem differ from more + + align:start position:0% +how does this problem differ from more + + + align:start position:0% +how does this problem differ from more +General tomography problems we encounter + + align:start position:0% +General tomography problems we encounter + + + align:start position:0% +General tomography problems we encounter +right like CT you know tomography when + + align:start position:0% +right like CT you know tomography when + + + align:start position:0% +right like CT you know tomography when +people do tomographic reconstru there's + + align:start position:0% +people do tomographic reconstru there's + + + align:start position:0% +people do tomographic reconstru there's +no tomography here we only have one line + + align:start position:0% +no tomography here we only have one line + + + align:start position:0% +no tomography here we only have one line +of s you can't do a tomographic + + align:start position:0% +of s you can't do a tomographic + + + align:start position:0% +of s you can't do a tomographic +reconstruction yeah I mean you can okay + + align:start position:0% +reconstruction yeah I mean you can okay + + + align:start position:0% +reconstruction yeah I mean you can okay +so now you can ask yourself if I have + + align:start position:0% +so now you can ask yourself if I have + + + align:start position:0% +so now you can ask yourself if I have +multiple lines of site can I do + + align:start position:0% +multiple lines of site can I do + + + align:start position:0% +multiple lines of site can I do +tomographic + + align:start position:0% +tomographic + + + align:start position:0% +tomographic +reconstruction which like yes obviously + + align:start position:0% +reconstruction which like yes obviously + + + align:start position:0% +reconstruction which like yes obviously +but it's also hard but you know it's + + align:start position:0% +but it's also hard but you know it's + + + align:start position:0% +but it's also hard but you know it's +might be possible but this is a single + + align:start position:0% +might be possible but this is a single + + + align:start position:0% +might be possible but this is a single +line of sight so we're not trying to ah + + align:start position:0% +line of sight so we're not trying to ah + + + align:start position:0% +line of sight so we're not trying to ah +thank you is the mistake I've been + + align:start position:0% +thank you is the mistake I've been + + + align:start position:0% +thank you is the mistake I've been +making we are not actually getting this + + align:start position:0% +making we are not actually getting this + + + align:start position:0% +making we are not actually getting this +out we are getting our best guess at + + align:start position:0% +out we are getting our best guess at + + + align:start position:0% +out we are getting our best guess at +this out right so this is not a full + + align:start position:0% +this out right so this is not a full + + + align:start position:0% +this out right so this is not a full +threedimensional + + align:start position:0% +threedimensional + + + align:start position:0% +threedimensional +reconstruction this is still a + + align:start position:0% +reconstruction this is still a + + + align:start position:0% +reconstruction this is still a +reconstruction of the line + + align:start position:0% +reconstruction of the line + + + align:start position:0% +reconstruction of the line +integrated uh electron it here so we + + align:start position:0% +integrated uh electron it here so we + + + align:start position:0% +integrated uh electron it here so we +yeah yeah that's a good point I forgot + + align:start position:0% +yeah yeah that's a good point I forgot + + + align:start position:0% +yeah yeah that's a good point I forgot +about that and so and it's sort of + + align:start position:0% +about that and so and it's sort of + + + align:start position:0% +about that and so and it's sort of +obvious that you should be able to do + + align:start position:0% +obvious that you should be able to do + + + align:start position:0% +obvious that you should be able to do +that but it's still there still can be + + align:start position:0% +that but it's still there still can be + + + align:start position:0% +that but it's still there still can be +multiple profiles that still produce the + + align:start position:0% +multiple profiles that still produce the + + + align:start position:0% +multiple profiles that still produce the +same intensity distribution so it's + + align:start position:0% +same intensity distribution so it's + + + align:start position:0% +same intensity distribution so it's +still not particularly well posed if you + + align:start position:0% +still not particularly well posed if you + + + align:start position:0% +still not particularly well posed if you +do have some cor sticks inside your + + align:start position:0% +do have some cor sticks inside your + + + align:start position:0% +do have some cor sticks inside your +detector image none of these work right + + align:start position:0% +detector image none of these work right + + + align:start position:0% +detector image none of these work right +so we no longer are able to do the + + align:start position:0% +so we no longer are able to do the + + + align:start position:0% +so we no longer are able to do the +Reconstruction you can actually have a + + align:start position:0% +Reconstruction you can actually have a + + + align:start position:0% +Reconstruction you can actually have a +go at doing the Reconstruction if you + + align:start position:0% +go at doing the Reconstruction if you + + + align:start position:0% +go at doing the Reconstruction if you +have some strong PRI so if you put you + + align:start position:0% +have some strong PRI so if you put you + + + align:start position:0% +have some strong PRI so if you put you +have some optimization algorithm that + + align:start position:0% +have some optimization algorithm that + + + align:start position:0% +have some optimization algorithm that +thinks like there's a shop here and that + + align:start position:0% +thinks like there's a shop here and that + + + align:start position:0% +thinks like there's a shop here and that +shop is going to cause cor sticks and I + + align:start position:0% +shop is going to cause cor sticks and I + + + align:start position:0% +shop is going to cause cor sticks and I +think the cor sticks will look like this + + align:start position:0% +think the cor sticks will look like this + + + align:start position:0% +think the cor sticks will look like this +you might be able to do it but of course + + align:start position:0% +you might be able to do it but of course + + + align:start position:0% +you might be able to do it but of course +you don't have Ro PRI the techniques are + + align:start position:0% +you don't have Ro PRI the techniques are + + + align:start position:0% +you don't have Ro PRI the techniques are +very line integrated as I just + + align:start position:0% +very line integrated as I just + + + align:start position:0% +very line integrated as I just +remembered and pointed out here so we're + + align:start position:0% +remembered and pointed out here so we're + + + align:start position:0% +remembered and pointed out here so we're +not getting the full 3d structure that's + + align:start position:0% +not getting the full 3d structure that's + + + align:start position:0% +not getting the full 3d structure that's +maybe a bit too much to ask from a + + align:start position:0% +maybe a bit too much to ask from a + + + align:start position:0% +maybe a bit too much to ask from a +diagnostic which is clearly integrated + + align:start position:0% +diagnostic which is clearly integrated + + + align:start position:0% +diagnostic which is clearly integrated +but it's still a limitation and then the + + align:start position:0% +but it's still a limitation and then the + + + align:start position:0% +but it's still a limitation and then the +final problem that uh in protal + + align:start position:0% +final problem that uh in protal + + + align:start position:0% +final problem that uh in protal +radiography is particularly profound is + + align:start position:0% +radiography is particularly profound is + + + align:start position:0% +radiography is particularly profound is +actually how + + align:start position:0% +actually how + + + align:start position:0% +actually how +reproducible this + + align:start position:0% +reproducible this + + + align:start position:0% +reproducible this +is how reproducible your initial reer + + align:start position:0% +is how reproducible your initial reer + + + align:start position:0% +is how reproducible your initial reer +I'm going to run out of + + align:start position:0% + + + + align:start position:0% + +space your initial intensity is because + + align:start position:0% +space your initial intensity is because + + + align:start position:0% +space your initial intensity is because +they before you do the experiment you + + align:start position:0% +they before you do the experiment you + + + align:start position:0% +they before you do the experiment you +find your La beam through the chamber + + align:start position:0% +find your La beam through the chamber + + + align:start position:0% +find your La beam through the chamber +and you measure that beam profile but + + align:start position:0% +and you measure that beam profile but + + + align:start position:0% +and you measure that beam profile but +then when you actually do the experiment + + align:start position:0% +then when you actually do the experiment + + + align:start position:0% +then when you actually do the experiment +that beam profile changes you know + + align:start position:0% +that beam profile changes you know + + + align:start position:0% +that beam profile changes you know +lasers are not completely stable the + + align:start position:0% +lasers are not completely stable the + + + align:start position:0% +lasers are not completely stable the +beam profile changes from time to time + + align:start position:0% +beam profile changes from time to time + + + align:start position:0% +beam profile changes from time to time +and so that means what you think you're + + align:start position:0% +and so that means what you think you're + + + align:start position:0% +and so that means what you think you're +mapping from here to here is actually + + align:start position:0% +mapping from here to here is actually + + + align:start position:0% +mapping from here to here is actually +slightly different and that's going to + + align:start position:0% +slightly different and that's going to + + + align:start position:0% +slightly different and that's going to +introduce Some Noise this is very um + + align:start position:0% +introduce Some Noise this is very um + + + align:start position:0% +introduce Some Noise this is very um +important for proton radiography where + + align:start position:0% +important for proton radiography where + + + align:start position:0% +important for proton radiography where +it's very hard to measure the beam for a + + align:start position:0% +it's very hard to measure the beam for a + + + align:start position:0% +it's very hard to measure the beam for a +laser chy setup you actually have more a + + align:start position:0% +laser chy setup you actually have more a + + + align:start position:0% +laser chy setup you actually have more a +chance you can put a beam split before + + align:start position:0% +chance you can put a beam split before + + + align:start position:0% +chance you can put a beam split before +the plasma and Sample the beam itself so + + align:start position:0% +the plasma and Sample the beam itself so + + + align:start position:0% +the plasma and Sample the beam itself so +you can actually simultaneously measure + + align:start position:0% +you can actually simultaneously measure + + + align:start position:0% +you can actually simultaneously measure +this Quant + + align:start position:0% +this Quant + + + align:start position:0% +this Quant +and this qu um so there's a lot of scope + + align:start position:0% +and this qu um so there's a lot of scope + + + align:start position:0% +and this qu um so there's a lot of scope +prod some really cool + + align:start position:0% +prod some really cool + + + align:start position:0% +prod some really cool +stuff + + align:start position:0% +stuff + + + align:start position:0% +stuff +questions yeah are obvious practical + + align:start position:0% +questions yeah are obvious practical + + + align:start position:0% +questions yeah are obvious practical +reasons why you wouldn't be + + align:start position:0% +reasons why you wouldn't be + + + align:start position:0% +reasons why you wouldn't be +measuring differences like I think it's + + align:start position:0% +measuring differences like I think it's + + + align:start position:0% +measuring differences like I think it's +a great idea no one's done it I want to + + align:start position:0% +a great idea no one's done it I want to + + + align:start position:0% +a great idea no one's done it I want to +do it yeah absolutely so it seems to me + + align:start position:0% +do it yeah absolutely so it seems to me + + + align:start position:0% +do it yeah absolutely so it seems to me +like if you have these images at + + align:start position:0% +like if you have these images at + + + align:start position:0% +like if you have these images at +different places you should be able to + + align:start position:0% +different places you should be able to + + + align:start position:0% +different places you should be able to +reconstruct the trajectories of the Rays + + align:start position:0% +reconstruct the trajectories of the Rays + + + align:start position:0% +reconstruct the trajectories of the Rays +and that would give you more information + + align:start position:0% +and that would give you more information + + + align:start position:0% +and that would give you more information +and in fact in some of the first + + align:start position:0% +and in fact in some of the first + + + align:start position:0% +and in fact in some of the first +radiography papers this is discussed + + align:start position:0% +radiography papers this is discussed + + + align:start position:0% +radiography papers this is discussed +from looking at like the position + + align:start position:0% +from looking at like the position + + + align:start position:0% +from looking at like the position +through multiple Stacks but I haven't + + align:start position:0% +through multiple Stacks but I haven't + + + align:start position:0% +through multiple Stacks but I haven't +seen it actually done practice kind of + + align:start position:0% +seen it actually done practice kind of + + + align:start position:0% +seen it actually done practice kind of +do + + align:start position:0% +do + + + align:start position:0% +do +it it's you + + align:start position:0% +it it's you + + + align:start position:0% +it it's you +know typically all your energy gets + + align:start position:0% +know typically all your energy gets + + + align:start position:0% +know typically all your energy gets +depit yeah so I think that's the problem + + align:start position:0% +depit yeah so I think that's the problem + + + align:start position:0% +depit yeah so I think that's the problem +but I I I like the idea like it's a cool + + align:start position:0% +but I I I like the idea like it's a cool + + + align:start position:0% +but I I I like the idea like it's a cool +like if it worked if people used this + + align:start position:0% +like if it worked if people used this + + + align:start position:0% +like if it worked if people used this +yeah so you can definitely do should be + + align:start position:0% +yeah so you can definitely do should be + + + align:start position:0% +yeah so you can definitely do should be +relatively straightforward yeah the + + align:start position:0% +relatively straightforward yeah the + + + align:start position:0% +relatively straightforward yeah the +other thing you can do is you could put + + align:start position:0% +other thing you can do is you could put + + + align:start position:0% +other thing you can do is you could put +multiple lasers different wavelengths + + align:start position:0% +multiple lasers different wavelengths + + + align:start position:0% +multiple lasers different wavelengths +through and they' be deflected by + + align:start position:0% +through and they' be deflected by + + + align:start position:0% +through and they' be deflected by +different angles and then you could use + + align:start position:0% +different angles and then you could use + + + align:start position:0% +different angles and then you could use +those different deflections like when + + align:start position:0% +those different deflections like when + + + align:start position:0% +those different deflections like when +you have your proton radiography and use + + align:start position:0% +you have your proton radiography and use + + + align:start position:0% +you have your proton radiography and use +different particle energies to determine + + align:start position:0% +different particle energies to determine + + + align:start position:0% +different particle energies to determine +between electric and magnetic fields uh + + align:start position:0% +between electric and magnetic fields uh + + + align:start position:0% +between electric and magnetic fields uh +here that we don't have uh electric and + + align:start position:0% +here that we don't have uh electric and + + + align:start position:0% +here that we don't have uh electric and +magnetic fields there's only one thing + + align:start position:0% +magnetic fields there's only one thing + + + align:start position:0% +magnetic fields there's only one thing +that can cause the deflection which is + + align:start position:0% +that can cause the deflection which is + + + align:start position:0% +that can cause the deflection which is +density gradients but those different + + align:start position:0% +density gradients but those different + + + align:start position:0% +density gradients but those different +colors will enable you to so you can + + align:start position:0% +colors will enable you to so you can + + + align:start position:0% +colors will enable you to so you can +imagine that one of your other Rays + + align:start position:0% +imagine that one of your other Rays + + + align:start position:0% +imagine that one of your other Rays +would get deflected less if it had a + + align:start position:0% +would get deflected less if it had a + + + align:start position:0% +would get deflected less if it had a +shorter wavelength and it would take a + + align:start position:0% +shorter wavelength and it would take a + + + align:start position:0% +shorter wavelength and it would take a +trajectory like that and by comparing + + align:start position:0% +trajectory like that and by comparing + + + align:start position:0% +trajectory like that and by comparing +where it ends up in one wavelength to + + align:start position:0% +where it ends up in one wavelength to + + + align:start position:0% +where it ends up in one wavelength to +where it ends up in the other like you + + align:start position:0% +where it ends up in the other like you + + + align:start position:0% +where it ends up in the other like you +should be able to actually precisely + + align:start position:0% +should be able to actually precisely + + + align:start position:0% +should be able to actually precisely +measure the angle made and therefore + + align:start position:0% +measure the angle made and therefore + + + align:start position:0% +measure the angle made and therefore +what I haven't seen anyone try that + + align:start position:0% +what I haven't seen anyone try that + + + align:start position:0% +what I haven't seen anyone try that +yet yeah when you're responding to J's + + align:start position:0% +yet yeah when you're responding to J's + + + align:start position:0% +yet yeah when you're responding to J's +question you mentioned that you know you + + align:start position:0% +question you mentioned that you know you + + + align:start position:0% +question you mentioned that you know you +only have one line of sight here but you + + align:start position:0% +only have one line of sight here but you + + + align:start position:0% +only have one line of sight here but you +know you're detector able to X and Y + + align:start position:0% +know you're detector able to X and Y + + + align:start position:0% +know you're detector able to X and Y +positions of + + align:start position:0% +positions of + + + align:start position:0% +positions of +your intensity you consider like each + + align:start position:0% +your intensity you consider like each + + + align:start position:0% +your intensity you consider like each +pixel as a different line of sight but + + align:start position:0% +pixel as a different line of sight but + + + align:start position:0% +pixel as a different line of sight but +it's only a cord through a certain bit + + align:start position:0% +it's only a cord through a certain bit + + + align:start position:0% +it's only a cord through a certain bit +of the plasma it's not a line of sight + + align:start position:0% +of the plasma it's not a line of sight + + + align:start position:0% +of the plasma it's not a line of sight +through the same bit of plasma when we + + align:start position:0% +through the same bit of plasma when we + + + align:start position:0% +through the same bit of plasma when we +do tomography you know you imagine + + align:start position:0% +do tomography you know you imagine + + + align:start position:0% +do tomography you know you imagine +you've got some cloud and you're looking + + align:start position:0% +you've got some cloud and you're looking + + + align:start position:0% +you've got some cloud and you're looking +through the same bit of plasma from + + align:start position:0% +through the same bit of plasma from + + + align:start position:0% +through the same bit of plasma from +multiple angles here you're looking at + + align:start position:0% +multiple angles here you're looking at + + + align:start position:0% +multiple angles here you're looking at +different bits of plasma so you can't + + align:start position:0% +different bits of plasma so you can't + + + align:start position:0% +different bits of plasma so you can't +tomographically reconstruct the density + + align:start position:0% +tomographically reconstruct the density + + + align:start position:0% +tomographically reconstruct the density +there because it's literally a different + + align:start position:0% +there because it's literally a different + + + align:start position:0% +there because it's literally a different +place in the + + align:start position:0% +place in the + + + align:start position:0% +place in the +plas um sure okay + + align:start position:0% +plas um sure okay + + + align:start position:0% +plas um sure okay +yes yeah um I would have expected like a + + align:start position:0% +yes yeah um I would have expected like a + + + align:start position:0% +yes yeah um I would have expected like a +smaller wave length to be deflected more + + align:start position:0% +smaller wave length to be deflected more + + + align:start position:0% +smaller wave length to be deflected more +because the length scale of the plasma + + align:start position:0% +because the length scale of the plasma + + + align:start position:0% +because the length scale of the plasma +you know + + align:start position:0% +you know + + + align:start position:0% +you know +large we are doing geometric optics so + + align:start position:0% +large we are doing geometric optics so + + + align:start position:0% +large we are doing geometric optics so +we don't actually care about the + + align:start position:0% +we don't actually care about the + + + align:start position:0% +we don't actually care about the +wavelengths yeah so in in systems where + + align:start position:0% +wavelengths yeah so in in systems where + + + align:start position:0% +wavelengths yeah so in in systems where +you're not doing geometric optics where + + align:start position:0% +you're not doing geometric optics where + + + align:start position:0% +you're not doing geometric optics where +the wavelength is comparable to the size + + align:start position:0% +the wavelength is comparable to the size + + + align:start position:0% +the wavelength is comparable to the size +of the plasma that would be a defraction + + align:start position:0% +of the plasma that would be a defraction + + + align:start position:0% +of the plasma that would be a defraction +effect and that would be more important + + align:start position:0% +effect and that would be more important + + + align:start position:0% +effect and that would be more important +but we are actually doing geometric + + align:start position:0% +but we are actually doing geometric + + + align:start position:0% +but we are actually doing geometric +optics where that isn't important but + + align:start position:0% +optics where that isn't important but + + + align:start position:0% +optics where that isn't important but +you're right so all of the stuff I've + + align:start position:0% +you're right so all of the stuff I've + + + align:start position:0% +you're right so all of the stuff I've +been doing the reason I drawing straight + + align:start position:0% +been doing the reason I drawing straight + + + align:start position:0% +been doing the reason I drawing straight +lines everywhere is I'm doing geometric + + align:start position:0% +lines everywhere is I'm doing geometric + + + align:start position:0% +lines everywhere is I'm doing geometric +optics I'm doing Ray Optics so in that + + align:start position:0% +optics I'm doing Ray Optics so in that + + + align:start position:0% +optics I'm doing Ray Optics so in that +case it come the different deflection + + align:start position:0% +case it come the different deflection + + + align:start position:0% +case it come the different deflection +angle comes about it because for short + + align:start position:0% +angle comes about it because for short + + + align:start position:0% +angle comes about it because for short +the wavelengths the critical density is + + align:start position:0% +the wavelengths the critical density is + + + align:start position:0% +the wavelengths the critical density is +higher and so this quantity becomes + + align:start position:0% +higher and so this quantity becomes + + + align:start position:0% +higher and so this quantity becomes +store this is just a little bit of a + + align:start position:0% +store this is just a little bit of a + + + align:start position:0% +store this is just a little bit of a +light-hearted little picture show and we + + align:start position:0% +light-hearted little picture show and we + + + align:start position:0% +light-hearted little picture show and we +may finish off the lecture with this so + + align:start position:0% +may finish off the lecture with this so + + + align:start position:0% +may finish off the lecture with this so +we might get started on deometry + + align:start position:0% +we might get started on deometry + + + align:start position:0% +we might get started on deometry +depending on how I feel um but here are + + align:start position:0% +depending on how I feel um but here are + + + align:start position:0% +depending on how I feel um but here are +some nice pictures uh phography is + + align:start position:0% +some nice pictures uh phography is + + + align:start position:0% +some nice pictures uh phography is +absolutely everywhere you have already + + align:start position:0% +absolutely everywhere you have already + + + align:start position:0% +absolutely everywhere you have already +seen many Shadow graphs before uh if + + align:start position:0% +seen many Shadow graphs before uh if + + + align:start position:0% +seen many Shadow graphs before uh if +you've ever seen a mirage uh that is a + + align:start position:0% +you've ever seen a mirage uh that is a + + + align:start position:0% +you've ever seen a mirage uh that is a +shadow graph that is the natural + + align:start position:0% +shadow graph that is the natural + + + align:start position:0% +shadow graph that is the natural +focusing of Light by refracted index + + align:start position:0% +focusing of Light by refracted index + + + align:start position:0% +focusing of Light by refracted index +gradients in hot air right and you see + + align:start position:0% +gradients in hot air right and you see + + + align:start position:0% +gradients in hot air right and you see +that shimmering you see the fact that + + align:start position:0% +that shimmering you see the fact that + + + align:start position:0% +that shimmering you see the fact that +there appear to be mountains below where + + align:start position:0% +there appear to be mountains below where + + + align:start position:0% +there appear to be mountains below where +the mountains actually are that's + + align:start position:0% +the mountains actually are that's + + + align:start position:0% +the mountains actually are that's +because the Rays of Light have been Bent + + align:start position:0% +because the Rays of Light have been Bent + + + align:start position:0% +because the Rays of Light have been Bent +by the hot there back upwards into your + + align:start position:0% +by the hot there back upwards into your + + + align:start position:0% +by the hot there back upwards into your +ey so this is what I mean when I say + + align:start position:0% +ey so this is what I mean when I say + + + align:start position:0% +ey so this is what I mean when I say +that shogy is not an image whenever you + + align:start position:0% +that shogy is not an image whenever you + + + align:start position:0% +that shogy is not an image whenever you +take a shogy thing what you're really + + align:start position:0% +take a shogy thing what you're really + + + align:start position:0% +take a shogy thing what you're really +seeing is some sort of + + align:start position:0% +seeing is some sort of + + + align:start position:0% +seeing is some sort of +Mirage so the first person to ever we + + align:start position:0% +Mirage so the first person to ever we + + + align:start position:0% +Mirage so the first person to ever we +know study cograph was this guy John Pat + + align:start position:0% +know study cograph was this guy John Pat + + + align:start position:0% +know study cograph was this guy John Pat +Uh that's a portrait of him here is his + + align:start position:0% +Uh that's a portrait of him here is his + + + align:start position:0% +Uh that's a portrait of him here is his +shadow GS he actually Drew these by hand + + align:start position:0% +shadow GS he actually Drew these by hand + + + align:start position:0% +shadow GS he actually Drew these by hand +because he didn't have cameras back in + + align:start position:0% +because he didn't have cameras back in + + + align:start position:0% +because he didn't have cameras back in +the day this is the guy he's in 1793 + + align:start position:0% +the day this is the guy he's in 1793 + + + align:start position:0% +the day this is the guy he's in 1793 +is's actually deeply unpleasant he was a + + align:start position:0% +is's actually deeply unpleasant he was a + + + align:start position:0% +is's actually deeply unpleasant he was a +jacobine he was responsible for deaths + + align:start position:0% +jacobine he was responsible for deaths + + + align:start position:0% +jacobine he was responsible for deaths +of hundreds of thousands of people in + + align:start position:0% +of hundreds of thousands of people in + + + align:start position:0% +of hundreds of thousands of people in +French Revolution and he was eventually + + align:start position:0% +French Revolution and he was eventually + + + align:start position:0% +French Revolution and he was eventually +murdered in the bathtub + + align:start position:0% +murdered in the bathtub + + + align:start position:0% +murdered in the bathtub +but before he was murdered he had a very + + align:start position:0% +but before he was murdered he had a very + + + align:start position:0% +but before he was murdered he had a very +famous guest he had a Prett famous guest + + align:start position:0% +famous guest he had a Prett famous guest + + + align:start position:0% +famous guest he had a Prett famous guest +who came and actually sat and he + + align:start position:0% +who came and actually sat and he + + + align:start position:0% +who came and actually sat and he +sketched the shadowgraphic effect of uh + + align:start position:0% +sketched the shadowgraphic effect of uh + + + align:start position:0% +sketched the shadowgraphic effect of uh +this uh the the effect of this guest's + + align:start position:0% +this uh the the effect of this guest's + + + align:start position:0% +this uh the the effect of this guest's +old head on on the air around so does + + align:start position:0% +old head on on the air around so does + + + align:start position:0% +old head on on the air around so does +anyone know who this is it is of course + + align:start position:0% +anyone know who this is it is of course + + + align:start position:0% +anyone know who this is it is of course +Ben Franklin so there we go who was made + + align:start position:0% +Ben Franklin so there we go who was made + + + align:start position:0% +Ben Franklin so there we go who was made +a habit of hanging around in France um + + align:start position:0% +a habit of hanging around in France um + + + align:start position:0% +a habit of hanging around in France um +um but these days we usually do things + + align:start position:0% +um but these days we usually do things + + + align:start position:0% +um but these days we usually do things +which are much more exciting than Ben + + align:start position:0% +which are much more exciting than Ben + + + align:start position:0% +which are much more exciting than Ben +Franklin's head so here are several + + align:start position:0% +Franklin's head so here are several + + + align:start position:0% +Franklin's head so here are several +different models uh these are models for + + align:start position:0% +different models uh these are models for + + + align:start position:0% +different models uh these are models for +the Gemini capsule um that was you know + + align:start position:0% +the Gemini capsule um that was you know + + + align:start position:0% +the Gemini capsule um that was you know +part of the American space program and + + align:start position:0% +part of the American space program and + + + align:start position:0% +part of the American space program and +they want to understand that the shop + + align:start position:0% +they want to understand that the shop + + + align:start position:0% +they want to understand that the shop +waves are around so you can see that + + align:start position:0% +waves are around so you can see that + + + align:start position:0% +waves are around so you can see that +this caption is coming from right to + + align:start position:0% +this caption is coming from right to + + + align:start position:0% +this caption is coming from right to +left it's got this blunt end here we + + align:start position:0% +left it's got this blunt end here we + + + align:start position:0% +left it's got this blunt end here we +have this very well defined bow shock + + align:start position:0% +have this very well defined bow shock + + + align:start position:0% +have this very well defined bow shock +structure here do we think that that's + + align:start position:0% +structure here do we think that that's + + + align:start position:0% +structure here do we think that that's +atic + + align:start position:0% + + + + align:start position:0% + +it's a big intensity variation right + + align:start position:0% +it's a big intensity variation right + + + align:start position:0% +it's a big intensity variation right +it's extremely black here and it's very + + align:start position:0% +it's extremely black here and it's very + + + align:start position:0% +it's extremely black here and it's very +bright around the outside here behind it + + align:start position:0% +bright around the outside here behind it + + + align:start position:0% +bright around the outside here behind it +what do we have we got a set of shocks + + align:start position:0% +what do we have we got a set of shocks + + + align:start position:0% +what do we have we got a set of shocks +there a shock here there's another set + + align:start position:0% +there a shock here there's another set + + + align:start position:0% +there a shock here there's another set +of shocks coming off here and here which + + align:start position:0% +of shocks coming off here and here which + + + align:start position:0% +of shocks coming off here and here which +interact with the outer shocks and then + + align:start position:0% +interact with the outer shocks and then + + + align:start position:0% +interact with the outer shocks and then +we have this beautifully turbulent flow + + align:start position:0% +we have this beautifully turbulent flow + + + align:start position:0% +we have this beautifully turbulent flow +behind it right and the same thing here + + align:start position:0% +behind it right and the same thing here + + + align:start position:0% +behind it right and the same thing here +on this uh more hemispherical object and + + align:start position:0% +on this uh more hemispherical object and + + + align:start position:0% +on this uh more hemispherical object and +so I don't know how big these were but + + align:start position:0% +so I don't know how big these were but + + + align:start position:0% +so I don't know how big these were but +you can do this in a wind tunnel in this + + align:start position:0% +you can do this in a wind tunnel in this + + + align:start position:0% +you can do this in a wind tunnel in this +case it was probably not a wind tunnel + + align:start position:0% +case it was probably not a wind tunnel + + + align:start position:0% +case it was probably not a wind tunnel +but a static gas that they fired these + + align:start position:0% +but a static gas that they fired these + + + align:start position:0% +but a static gas that they fired these +through with a cannon and then they + + align:start position:0% +through with a cannon and then they + + + align:start position:0% +through with a cannon and then they +would have used some sort of bright + + align:start position:0% +would have used some sort of bright + + + align:start position:0% +would have used some sort of bright +light source probably not a laser in + + align:start position:0% +light source probably not a laser in + + + align:start position:0% +light source probably not a laser in +order to do + + align:start position:0% +order to do + + + align:start position:0% +order to do +this um also when you start looking the + + align:start position:0% +this um also when you start looking the + + + align:start position:0% +this um also when you start looking the +literature you get lots of beautiful + + align:start position:0% +literature you get lots of beautiful + + + align:start position:0% +literature you get lots of beautiful +pictures of bullets bullets are + + align:start position:0% +pictures of bullets bullets are + + + align:start position:0% +pictures of bullets bullets are +particularly good sources so um I + + align:start position:0% +particularly good sources so um I + + + align:start position:0% +particularly good sources so um I +believe in this picture the gun is just + + align:start position:0% +believe in this picture the gun is just + + + align:start position:0% +believe in this picture the gun is just +here and so you can see the cloud of uh + + align:start position:0% +here and so you can see the cloud of uh + + + align:start position:0% +here and so you can see the cloud of uh +exhaust Vapor coming out of the Gun + + align:start position:0% +exhaust Vapor coming out of the Gun + + + align:start position:0% +exhaust Vapor coming out of the Gun +Barrel you can see this is the sound + + align:start position:0% +Barrel you can see this is the sound + + + align:start position:0% +Barrel you can see this is the sound +wave of the the shot going off and then + + align:start position:0% +wave of the the shot going off and then + + + align:start position:0% +wave of the the shot going off and then +supersonically moving away from the gun + + align:start position:0% +supersonically moving away from the gun + + + align:start position:0% +supersonically moving away from the gun +is the bullet we can see the trail with + + align:start position:0% +is the bullet we can see the trail with + + + align:start position:0% +is the bullet we can see the trail with +the uh fine structure behind it and + + align:start position:0% +the uh fine structure behind it and + + + align:start position:0% +the uh fine structure behind it and +these very clearly defined shock waves + + align:start position:0% +these very clearly defined shock waves + + + align:start position:0% +these very clearly defined shock waves +here and again the shock waves have + + align:start position:0% +here and again the shock waves have + + + align:start position:0% +here and again the shock waves have +these light and dark regions + + align:start position:0% +these light and dark regions + + + align:start position:0% +these light and dark regions +corresponding to changes in the fact + + align:start position:0% +corresponding to changes in the fact + + + align:start position:0% +corresponding to changes in the fact +index and this is I think a zoom in of + + align:start position:0% +index and this is I think a zoom in of + + + align:start position:0% +index and this is I think a zoom in of +that photograph I can't be sure it looks + + align:start position:0% +that photograph I can't be sure it looks + + + align:start position:0% +that photograph I can't be sure it looks +like it is + + align:start position:0% +like it is + + + align:start position:0% +like it is +um of that so you can see you get an + + align:start position:0% +um of that so you can see you get an + + + align:start position:0% +um of that so you can see you get an +extraordinary amount of qualitative + + align:start position:0% +extraordinary amount of qualitative + + + align:start position:0% +extraordinary amount of qualitative +detail what you can measure from this + + align:start position:0% +detail what you can measure from this + + + align:start position:0% +detail what you can measure from this +straight away is the shock opening angle + + align:start position:0% +straight away is the shock opening angle + + + align:start position:0% +straight away is the shock opening angle +so you can measure the mark number + + align:start position:0% +so you can measure the mark number + + + align:start position:0% +so you can measure the mark number +what's going to be a lot more tricky + + align:start position:0% +what's going to be a lot more tricky + + + align:start position:0% +what's going to be a lot more tricky +look at these pictures is to work out + + align:start position:0% +look at these pictures is to work out + + + align:start position:0% +look at these pictures is to work out +what the density and temperature of the + + align:start position:0% +what the density and temperature of the + + + align:start position:0% +what the density and temperature of the +air is everywhere inside this picture + + align:start position:0% +air is everywhere inside this picture + + + align:start position:0% +air is everywhere inside this picture +that's not really going to be doable um + + align:start position:0% +that's not really going to be doable um + + + align:start position:0% +that's not really going to be doable um +because we're not in this small + + align:start position:0% +because we're not in this small + + + align:start position:0% +because we're not in this small +intensity variation regime we've + + align:start position:0% +intensity variation regime we've + + + align:start position:0% +intensity variation regime we've +deliberately gone into the regime where + + align:start position:0% +deliberately gone into the regime where + + + align:start position:0% +deliberately gone into the regime where +we get Co stics which means we also get + + align:start position:0% +we get Co stics which means we also get + + + align:start position:0% +we get Co stics which means we also get +strong intensity variation so we can + + align:start position:0% +strong intensity variation so we can + + + align:start position:0% +strong intensity variation so we can +actually measure if we were looking at + + align:start position:0% +actually measure if we were looking at + + + align:start position:0% +actually measure if we were looking at +on those small intensity variation + + align:start position:0% +on those small intensity variation + + + align:start position:0% +on those small intensity variation +shatter graphs it would be very boring + + align:start position:0% +shatter graphs it would be very boring + + + align:start position:0% +shatter graphs it would be very boring +it would mostly be gray we very very + + align:start position:0% +it would mostly be gray we very very + + + align:start position:0% +it would mostly be gray we very very +tiny modulations so yeah on the on + + align:start position:0% +tiny modulations so yeah on the on + + + align:start position:0% +tiny modulations so yeah on the on +figure B why are the light and do + + align:start position:0% +figure B why are the light and do + + + align:start position:0% +figure B why are the light and do +regions above and below + + align:start position:0% + + + + align:start position:0% + +SWAT I'll put on on the problem + + align:start position:0% +SWAT I'll put on on the problem + + + align:start position:0% +SWAT I'll put on on the problem +set I don't know immediately uh why that + + align:start position:0% +set I don't know immediately uh why that + + + align:start position:0% +set I don't know immediately uh why that +is the thing is also to remember if you + + align:start position:0% +is the thing is also to remember if you + + + align:start position:0% +is the thing is also to remember if you +end up in a regime where you have cor + + align:start position:0% +end up in a regime where you have cor + + + align:start position:0% +end up in a regime where you have cor +sticks and you have strong deflections + + align:start position:0% +sticks and you have strong deflections + + + align:start position:0% +sticks and you have strong deflections +of your rays you may actually end up in + + align:start position:0% +of your rays you may actually end up in + + + align:start position:0% +of your rays you may actually end up in +a regime where the Rays don't go through + + align:start position:0% +a regime where the Rays don't go through + + + align:start position:0% +a regime where the Rays don't go through +your first Optics so they may be + + align:start position:0% +your first Optics so they may be + + + align:start position:0% +your first Optics so they may be +deflected out of the collection volume + + align:start position:0% +deflected out of the collection volume + + + align:start position:0% +deflected out of the collection volume +of your first optic and then they will + + align:start position:0% +of your first optic and then they will + + + align:start position:0% +of your first optic and then they will +just shut as dark regions so you can + + align:start position:0% +just shut as dark regions so you can + + + align:start position:0% +just shut as dark regions so you can +also have overlay theography effects + + align:start position:0% +also have overlay theography effects + + + align:start position:0% +also have overlay theography effects +what are effectively scharen type + + align:start position:0% +what are effectively scharen type + + + align:start position:0% +what are effectively scharen type +effects where we are rejecting Rays by + + align:start position:0% +effects where we are rejecting Rays by + + + align:start position:0% +effects where we are rejecting Rays by +their angle but that's just due to the + + align:start position:0% +their angle but that's just due to the + + + align:start position:0% +their angle but that's just due to the +physical SI of the Optics we use so I + + align:start position:0% +physical SI of the Optics we use so I + + + align:start position:0% +physical SI of the Optics we use so I +don't know if that's the case here but + + align:start position:0% +don't know if that's the case here but + + + align:start position:0% +don't know if that's the case here but +it does complicate the interpretation + + align:start position:0% +it does complicate the interpretation + + + align:start position:0% +it does complicate the interpretation +further yes in the previous pictures + + align:start position:0% +further yes in the previous pictures + + + align:start position:0% +further yes in the previous pictures +with the J capsules um there's like + + align:start position:0% +with the J capsules um there's like + + + align:start position:0% +with the J capsules um there's like +there's the effect of pressure waves + + align:start position:0% +there's the effect of pressure waves + + + align:start position:0% +there's the effect of pressure waves +shock waves and there's also like + + align:start position:0% +shock waves and there's also like + + + align:start position:0% +shock waves and there's also like +supposedly intense Heating that + + align:start position:0% +supposedly intense Heating that + + + align:start position:0% +supposedly intense Heating that +shouldn't be like on the + + align:start position:0% +shouldn't be like on the + + + align:start position:0% +shouldn't be like on the +surface and that's also going to change + + align:start position:0% +surface and that's also going to change + + + align:start position:0% +surface and that's also going to change +refra yes which effect of those like how + + align:start position:0% +refra yes which effect of those like how + + + align:start position:0% +refra yes which effect of those like how +could we distinguish it something it's + + align:start position:0% +could we distinguish it something it's + + + align:start position:0% +could we distinguish it something it's +like the termal refra index change or + + align:start position:0% +like the termal refra index change or + + + align:start position:0% +like the termal refra index change or +pressure in air in air yeah I think + + align:start position:0% +pressure in air in air yeah I think + + + align:start position:0% +pressure in air in air yeah I think +that's very difficult because they both + + align:start position:0% +that's very difficult because they both + + + align:start position:0% +that's very difficult because they both +are just the change in refractive index + + align:start position:0% +are just the change in refractive index + + + align:start position:0% +are just the change in refractive index +um yeah I don't think it's possible to + + align:start position:0% +um yeah I don't think it's possible to + + + align:start position:0% +um yeah I don't think it's possible to +tell the difference between those two + + align:start position:0% +tell the difference between those two + + + align:start position:0% +tell the difference between those two +yeah + + align:start position:0% + + + + align:start position:0% + +um there's also some funky pictures in + + align:start position:0% +um there's also some funky pictures in + + + align:start position:0% +um there's also some funky pictures in +this book this looks pretty + + align:start position:0% +this book this looks pretty + + + align:start position:0% +this book this looks pretty +straightforward the bullets is actually + + align:start position:0% +straightforward the bullets is actually + + + align:start position:0% +straightforward the bullets is actually +flying + + align:start position:0% +flying + + + align:start position:0% +flying +backwards I don't know why they did that + + align:start position:0% +backwards I don't know why they did that + + + align:start position:0% +backwards I don't know why they did that +but there we go this is a great book by + + align:start position:0% +but there we go this is a great book by + + + align:start position:0% +but there we go this is a great book by +the way settled sh a shadowgraph + + align:start position:0% +the way settled sh a shadowgraph + + + align:start position:0% +the way settled sh a shadowgraph +techniques it's got wonderful pictures + + align:start position:0% +techniques it's got wonderful pictures + + + align:start position:0% +techniques it's got wonderful pictures +inside it if you want to know more about + + align:start position:0% +inside it if you want to know more about + + + align:start position:0% +inside it if you want to know more about +this it's in bibliography uh on the + + align:start position:0% +this it's in bibliography uh on the + + + align:start position:0% +this it's in bibliography uh on the +syllabus and it's a great read but I + + align:start position:0% +syllabus and it's a great read but I + + + align:start position:0% +syllabus and it's a great read but I +appreciate most people not going to be + + align:start position:0% +appreciate most people not going to be + + + align:start position:0% +appreciate most people not going to be +using chirography in schen but still + + align:start position:0% +using chirography in schen but still + + + align:start position:0% +using chirography in schen but still +good stuff + + align:start position:0% +good stuff + + + align:start position:0% +good stuff +um but you don't have to fire bullets at + + align:start position:0% +um but you don't have to fire bullets at + + + align:start position:0% +um but you don't have to fire bullets at +things this is actually a picture of the + + align:start position:0% +things this is actually a picture of the + + + align:start position:0% +things this is actually a picture of the +author of this book writing his book + + align:start position:0% +author of this book writing his book + + + align:start position:0% +author of this book writing his book +next speing unit there he is head not + + align:start position:0% +next speing unit there he is head not + + + align:start position:0% +next speing unit there he is head not +impressive as Frank that there's his + + align:start position:0% +impressive as Frank that there's his + + + align:start position:0% +impressive as Frank that there's his +computer as he types away and you can + + align:start position:0% +computer as he types away and you can + + + align:start position:0% +computer as he types away and you can +see that you can actually make these + + align:start position:0% +see that you can actually make these + + + align:start position:0% +see that you can actually make these +measurements um even in relatively + + align:start position:0% +measurements um even in relatively + + + align:start position:0% +measurements um even in relatively +benign condition and that's because + + align:start position:0% +benign condition and that's because + + + align:start position:0% +benign condition and that's because +again if we put our detector further and + + align:start position:0% +again if we put our detector further and + + + align:start position:0% +again if we put our detector further and +further back even small variations in + + align:start position:0% +further back even small variations in + + + align:start position:0% +further back even small variations in +the angle going through the refra medium + + align:start position:0% +the angle going through the refra medium + + + align:start position:0% +the angle going through the refra medium +are going to be mapped into large + + align:start position:0% +are going to be mapped into large + + + align:start position:0% +are going to be mapped into large +intensity variations so people use this + + align:start position:0% +intensity variations so people use this + + + align:start position:0% +intensity variations so people use this +technique to look for flows or air you + + align:start position:0% +technique to look for flows or air you + + + align:start position:0% +technique to look for flows or air you +can look for flows of air for all sorts + + align:start position:0% +can look for flows of air for all sorts + + + align:start position:0% +can look for flows of air for all sorts +of reasons a pretty benign reason would + + align:start position:0% +of reasons a pretty benign reason would + + + align:start position:0% +of reasons a pretty benign reason would +be in the H track industry if you want + + align:start position:0% +be in the H track industry if you want + + + align:start position:0% +be in the H track industry if you want +to see whether these things are working + + align:start position:0% +to see whether these things are working + + + align:start position:0% +to see whether these things are working +so there are applications for + + align:start position:0% +so there are applications for + + + align:start position:0% +so there are applications for +shadowgraphic techniques and Sh + + align:start position:0% +shadowgraphic techniques and Sh + + + align:start position:0% +shadowgraphic techniques and Sh +techniques just in very like benign + + align:start position:0% +techniques just in very like benign + + + align:start position:0% +techniques just in very like benign +conditions like + + align:start position:0% +conditions like + + + align:start position:0% +conditions like +this but we of course are interested in + + align:start position:0% +this but we of course are interested in + + + align:start position:0% +this but we of course are interested in +plasmas uh so we talked about this a + + align:start position:0% +plasmas uh so we talked about this a + + + align:start position:0% +plasmas uh so we talked about this a +little bit more on the last lecture but + + align:start position:0% +little bit more on the last lecture but + + + align:start position:0% +little bit more on the last lecture but +remember that we need a very bright + + align:start position:0% +remember that we need a very bright + + + align:start position:0% +remember that we need a very bright +light source to overcome the self + + align:start position:0% +light source to overcome the self + + + align:start position:0% +light source to overcome the self +emission from a plasma so that means we + + align:start position:0% +emission from a plasma so that means we + + + align:start position:0% +emission from a plasma so that means we +really have to go to a laser we just + + align:start position:0% +really have to go to a laser we just + + + align:start position:0% +really have to go to a laser we just +don't have any light sources that are + + align:start position:0% +don't have any light sources that are + + + align:start position:0% +don't have any light sources that are +great lasers are actually not ideal for + + align:start position:0% +great lasers are actually not ideal for + + + align:start position:0% +great lasers are actually not ideal for +any of these techniques you really want + + align:start position:0% +any of these techniques you really want + + + align:start position:0% +any of these techniques you really want +to have a nice large focal spot that + + align:start position:0% +to have a nice large focal spot that + + + align:start position:0% +to have a nice large focal spot that +turns out to be true for shog graphy as + + align:start position:0% +turns out to be true for shog graphy as + + + align:start position:0% +turns out to be true for shog graphy as +well but we didn't really go into why uh + + align:start position:0% +well but we didn't really go into why uh + + + align:start position:0% +well but we didn't really go into why uh +and so this small focal spot gives us + + align:start position:0% +and so this small focal spot gives us + + + align:start position:0% +and so this small focal spot gives us +quite limited dynamic range not to + + align:start position:0% +quite limited dynamic range not to + + + align:start position:0% +quite limited dynamic range not to +mention the fact that we are assuming in + + align:start position:0% +mention the fact that we are assuming in + + + align:start position:0% +mention the fact that we are assuming in +all of this that we don't have any + + align:start position:0% +all of this that we don't have any + + + align:start position:0% +all of this that we don't have any +coherence effects so we don't have + + align:start position:0% +coherence effects so we don't have + + + align:start position:0% +coherence effects so we don't have +interference and we'll talk a lot about + + align:start position:0% +interference and we'll talk a lot about + + + align:start position:0% +interference and we'll talk a lot about +interference in a little bit and so uh + + align:start position:0% +interference in a little bit and so uh + + + align:start position:0% +interference in a little bit and so uh +really we don't want to have that + + align:start position:0% +really we don't want to have that + + + align:start position:0% +really we don't want to have that +coherence when we're doing schin and + + align:start position:0% +coherence when we're doing schin and + + + align:start position:0% +coherence when we're doing schin and +shog graphy but if we've got a laser we + + align:start position:0% +shog graphy but if we've got a laser we + + + align:start position:0% +shog graphy but if we've got a laser we +tend to have coher appearance that we + + align:start position:0% +tend to have coher appearance that we + + + align:start position:0% +tend to have coher appearance that we +don't want so these are not great but + + align:start position:0% +don't want so these are not great but + + + align:start position:0% +don't want so these are not great but +you can still get some nice images out + + align:start position:0% +you can still get some nice images out + + + align:start position:0% +you can still get some nice images out +of it um here's a device called an X + + align:start position:0% +of it um here's a device called an X + + + align:start position:0% +of it um here's a device called an X +pinch um it consists of two wires that + + align:start position:0% +pinch um it consists of two wires that + + + align:start position:0% +pinch um it consists of two wires that +are crossed here this is only one + + align:start position:0% +are crossed here this is only one + + + align:start position:0% +are crossed here this is only one +millimeter across here so this is a + + align:start position:0% +millimeter across here so this is a + + + align:start position:0% +millimeter across here so this is a +pretty small object and these are X-ray + + align:start position:0% +pretty small object and these are X-ray + + + align:start position:0% +pretty small object and these are X-ray +gated x-ray images of the X pinch we put + + align:start position:0% +gated x-ray images of the X pinch we put + + + align:start position:0% +gated x-ray images of the X pinch we put +in this case 200 kiloamps through each + + align:start position:0% +in this case 200 kiloamps through each + + + align:start position:0% +in this case 200 kiloamps through each +wire and it forms a plasma here which + + align:start position:0% +wire and it forms a plasma here which + + + align:start position:0% +wire and it forms a plasma here which +pinches the fields here are maybe 100 or + + align:start position:0% +pinches the fields here are maybe 100 or + + + align:start position:0% +pinches the fields here are maybe 100 or +a thousand Tesla and it pinches the + + align:start position:0% +a thousand Tesla and it pinches the + + + align:start position:0% +a thousand Tesla and it pinches the +plasma inwards like this compressing it + + align:start position:0% +plasma inwards like this compressing it + + + align:start position:0% +plasma inwards like this compressing it +up so it becomes extremely hot and it + + align:start position:0% +up so it becomes extremely hot and it + + + align:start position:0% +up so it becomes extremely hot and it +emits a burst of x-rays which you can + + align:start position:0% +emits a burst of x-rays which you can + + + align:start position:0% +emits a burst of x-rays which you can +then use for Imaging things so when we + + align:start position:0% +then use for Imaging things so when we + + + align:start position:0% +then use for Imaging things so when we +get on to uh self mission Diagnostics + + align:start position:0% +get on to uh self mission Diagnostics + + + align:start position:0% +get on to uh self mission Diagnostics +xray Diagnostics we'll talk a little bit + + align:start position:0% +xray Diagnostics we'll talk a little bit + + + align:start position:0% +xray Diagnostics we'll talk a little bit +about this so these are the x-ray images + + align:start position:0% +about this so these are the x-ray images + + + align:start position:0% +about this so these are the x-ray images +but this rather beautiful schan image + + align:start position:0% +but this rather beautiful schan image + + + align:start position:0% +but this rather beautiful schan image +was captured of this x pinch uh in 2008 + + align:start position:0% +was captured of this x pinch uh in 2008 + + + align:start position:0% +was captured of this x pinch uh in 2008 +here they used a dark field schan system + + align:start position:0% +here they used a dark field schan system + + + align:start position:0% +here they used a dark field schan system +is a circular stop you can tell that + + align:start position:0% +is a circular stop you can tell that + + + align:start position:0% +is a circular stop you can tell that +because it looks up down symmetric so + + align:start position:0% +because it looks up down symmetric so + + + align:start position:0% +because it looks up down symmetric so +we're not we don't have a nice stage + + align:start position:0% +we're not we don't have a nice stage + + + align:start position:0% +we're not we don't have a nice stage +where we have some distinction uh + + align:start position:0% +where we have some distinction uh + + + align:start position:0% +where we have some distinction uh +between the different directions and you + + align:start position:0% +between the different directions and you + + + align:start position:0% +between the different directions and you +can tell it dark field because outside + + align:start position:0% +can tell it dark field because outside + + + align:start position:0% +can tell it dark field because outside +where there is no plasma it's dark here + + align:start position:0% +where there is no plasma it's dark here + + + align:start position:0% +where there is no plasma it's dark here +if it was light field this region would + + align:start position:0% +if it was light field this region would + + + align:start position:0% +if it was light field this region would +be filled with laser light and we'd have + + align:start position:0% +be filled with laser light and we'd have + + + align:start position:0% +be filled with laser light and we'd have +Darkness whereever we have lightness + + align:start position:0% +Darkness whereever we have lightness + + + align:start position:0% +Darkness whereever we have lightness +here and you can see a beautiful amount + + align:start position:0% +here and you can see a beautiful amount + + + align:start position:0% +here and you can see a beautiful amount +of detail this projector isn't really + + align:start position:0% +of detail this projector isn't really + + + align:start position:0% +of detail this projector isn't really +doing it justice um you can see in the + + align:start position:0% +doing it justice um you can see in the + + + align:start position:0% +doing it justice um you can see in the +center here this is the pinching region + + align:start position:0% +center here this is the pinching region + + + align:start position:0% +center here this is the pinching region +it's far too dense for all of the laser + + align:start position:0% +it's far too dense for all of the laser + + + align:start position:0% +it's far too dense for all of the laser +light to make it through it's much above + + align:start position:0% +light to make it through it's much above + + + align:start position:0% +light to make it through it's much above +the critical density and so there's very + + align:start position:0% +the critical density and so there's very + + + align:start position:0% +the critical density and so there's very +strong refraction of the laser light + + align:start position:0% +strong refraction of the laser light + + + align:start position:0% +strong refraction of the laser light +outwards dark in the center there's Jets + + align:start position:0% +outwards dark in the center there's Jets + + + align:start position:0% +outwards dark in the center there's Jets +of plasma going up and down out of this + + align:start position:0% +of plasma going up and down out of this + + + align:start position:0% +of plasma going up and down out of this +compressed region and there's also + + align:start position:0% +compressed region and there's also + + + align:start position:0% +compressed region and there's also +oblation streams coming off each of the + + align:start position:0% +oblation streams coming off each of the + + + align:start position:0% +oblation streams coming off each of the +wires which have this beautiful + + align:start position:0% +wires which have this beautiful + + + align:start position:0% +wires which have this beautiful +modulated pattern which is actually due + + align:start position:0% +modulated pattern which is actually due + + + align:start position:0% +modulated pattern which is actually due +to a instability in The Wire abelation + + align:start position:0% +to a instability in The Wire abelation + + + align:start position:0% +to a instability in The Wire abelation +process so this is extremely rich + + align:start position:0% +process so this is extremely rich + + + align:start position:0% +process so this is extremely rich +there's a lot of information you can get + + align:start position:0% +there's a lot of information you can get + + + align:start position:0% +there's a lot of information you can get +out of this even though it's not + + align:start position:0% + + + + align:start position:0% + +modated another thing that's been done + + align:start position:0% +modated another thing that's been done + + + align:start position:0% +modated another thing that's been done +is using schen Imaging to image shocks + + align:start position:0% +is using schen Imaging to image shocks + + + align:start position:0% +is using schen Imaging to image shocks +uh in uh what's initially a gas but + + align:start position:0% +uh in uh what's initially a gas but + + + align:start position:0% +uh in uh what's initially a gas but +quickly becomes a plas + + align:start position:0% +quickly becomes a plas + + + align:start position:0% +quickly becomes a plas +so what we had in these experiments was + + align:start position:0% +so what we had in these experiments was + + + align:start position:0% +so what we had in these experiments was +a metal liner this is only about 5 mm + + align:start position:0% +a metal liner this is only about 5 mm + + + align:start position:0% +a metal liner this is only about 5 mm +across and it's still pretty small and + + align:start position:0% +across and it's still pretty small and + + + align:start position:0% +across and it's still pretty small and +it was filled with a gas 8 MBS of argon + + align:start position:0% +it was filled with a gas 8 MBS of argon + + + align:start position:0% +it was filled with a gas 8 MBS of argon +15 Ms of nitrogen uh a current was put + + align:start position:0% +15 Ms of nitrogen uh a current was put + + + align:start position:0% +15 Ms of nitrogen uh a current was put +up through this metal cylinder again the + + align:start position:0% +up through this metal cylinder again the + + + align:start position:0% +up through this metal cylinder again the +cylinder is only about that tall and + + align:start position:0% +cylinder is only about that tall and + + + align:start position:0% +cylinder is only about that tall and +that wide and as it does so it heats the + + align:start position:0% +that wide and as it does so it heats the + + + align:start position:0% +that wide and as it does so it heats the +outside of the cylinder and launches a + + align:start position:0% +outside of the cylinder and launches a + + + align:start position:0% +outside of the cylinder and launches a +shock wave inwards and that shock wave + + align:start position:0% +shock wave inwards and that shock wave + + + align:start position:0% +shock wave inwards and that shock wave +couples the gas and it launches this + + align:start position:0% +couples the gas and it launches this + + + align:start position:0% +couples the gas and it launches this +first shock wave in and as the current + + align:start position:0% +first shock wave in and as the current + + + align:start position:0% +first shock wave in and as the current +continues to rise you actually get above + + align:start position:0% +continues to rise you actually get above + + + align:start position:0% +continues to rise you actually get above +the Melt point of the metal and that + + align:start position:0% +the Melt point of the metal and that + + + align:start position:0% +the Melt point of the metal and that +launches another shock wave due to + + align:start position:0% +launches another shock wave due to + + + align:start position:0% +launches another shock wave due to +material strength that starts coming in + + align:start position:0% +material strength that starts coming in + + + align:start position:0% +material strength that starts coming in +so we get these converging shock waves + + align:start position:0% +so we get these converging shock waves + + + align:start position:0% +so we get these converging shock waves +the beautiful thing here is that in + + align:start position:0% +the beautiful thing here is that in + + + align:start position:0% +the beautiful thing here is that in +argon we had a beautifully circular + + align:start position:0% +argon we had a beautifully circular + + + align:start position:0% +argon we had a beautifully circular +shock but in nitrogen for some reason we + + align:start position:0% +shock but in nitrogen for some reason we + + + align:start position:0% +shock but in nitrogen for some reason we +got like this hexagonal shape of shock + + align:start position:0% +got like this hexagonal shape of shock + + + align:start position:0% +got like this hexagonal shape of shock +which has never been explained + + align:start position:0% +which has never been explained + + + align:start position:0% +which has never been explained +absolutely bizarre there's no sixfold + + align:start position:0% +absolutely bizarre there's no sixfold + + + align:start position:0% +absolutely bizarre there's no sixfold +symmetry in this system it shouldn't + + align:start position:0% +symmetry in this system it shouldn't + + + align:start position:0% +symmetry in this system it shouldn't +have it so there's some instability + + align:start position:0% +have it so there's some instability + + + align:start position:0% +have it so there's some instability +which is giving it this uh really + + align:start position:0% +which is giving it this uh really + + + align:start position:0% +which is giving it this uh really +bizarre shape and again this was dark + + align:start position:0% +bizarre shape and again this was dark + + + align:start position:0% +bizarre shape and again this was dark +field with a circular stop that's a + + align:start position:0% +field with a circular stop that's a + + + align:start position:0% +field with a circular stop that's a +pretty standard configuration dark field + + align:start position:0% +pretty standard configuration dark field + + + align:start position:0% +pretty standard configuration dark field +is a bit more sensitive than light field + + align:start position:0% +is a bit more sensitive than light field + + + align:start position:0% +is a bit more sensitive than light field +because if you see any light at all you + + align:start position:0% +because if you see any light at all you + + + align:start position:0% +because if you see any light at all you +know that it's been deflected and that's + + align:start position:0% +know that it's been deflected and that's + + + align:start position:0% +know that it's been deflected and that's +really what you're looking for + + align:start position:0% + + + + align:start position:0% + +here and then + + align:start position:0% +here and then + + + align:start position:0% +here and then +phography uh this is an image that I + + align:start position:0% +phography uh this is an image that I + + + align:start position:0% +phography uh this is an image that I +took of uh an imploding wire array so + + align:start position:0% +took of uh an imploding wire array so + + + align:start position:0% +took of uh an imploding wire array so +again this thing is only about 16 + + align:start position:0% +again this thing is only about 16 + + + align:start position:0% +again this thing is only about 16 +millimeters tall 16 millim in diameter + + align:start position:0% +millimeters tall 16 millim in diameter + + + align:start position:0% +millimeters tall 16 millim in diameter +we've got eight carbon rods here current + + align:start position:0% +we've got eight carbon rods here current + + + align:start position:0% +we've got eight carbon rods here current +goes up through the rods the blades + + align:start position:0% +goes up through the rods the blades + + + align:start position:0% +goes up through the rods the blades +plasma of them jross B Force accelerates + + align:start position:0% +plasma of them jross B Force accelerates + + + align:start position:0% +plasma of them jross B Force accelerates +theas inwards and you get a z pinch + + align:start position:0% +theas inwards and you get a z pinch + + + align:start position:0% +theas inwards and you get a z pinch +column in the center here and looking + + align:start position:0% +column in the center here and looking + + + align:start position:0% +column in the center here and looking +from the side using a green laser beam + + align:start position:0% +from the side using a green laser beam + + + align:start position:0% +from the side using a green laser beam +uh we can see that we've got Shadows + + align:start position:0% +uh we can see that we've got Shadows + + + align:start position:0% +uh we can see that we've got Shadows +corresponding to the four wires so + + align:start position:0% +corresponding to the four wires so + + + align:start position:0% +corresponding to the four wires so +there's four wires on this side and + + align:start position:0% +there's four wires on this side and + + + align:start position:0% +there's four wires on this side and +they're blocking the four wires on the + + align:start position:0% +they're blocking the four wires on the + + + align:start position:0% +they're blocking the four wires on the +other side and you can see the column of + + align:start position:0% +other side and you can see the column of + + + align:start position:0% +other side and you can see the column of +plasma in the middle here and what you + + align:start position:0% +plasma in the middle here and what you + + + align:start position:0% +plasma in the middle here and what you +can see is there these very strong + + align:start position:0% +can see is there these very strong + + + align:start position:0% +can see is there these very strong +modulations to the intensity these are + + align:start position:0% +modulations to the intensity these are + + + align:start position:0% +modulations to the intensity these are +Co sticks okay we also see modulations + + align:start position:0% +Co sticks okay we also see modulations + + + align:start position:0% +Co sticks okay we also see modulations +to the flow as we saw in the exit and + + align:start position:0% +to the flow as we saw in the exit and + + + align:start position:0% +to the flow as we saw in the exit and +these Co sticks mean that this data + + align:start position:0% +these Co sticks mean that this data + + + align:start position:0% +these Co sticks mean that this data +while very pretty is pretty useless + + align:start position:0% +while very pretty is pretty useless + + + align:start position:0% +while very pretty is pretty useless +there's not much we can actually do with + + align:start position:0% +there's not much we can actually do with + + + align:start position:0% +there's not much we can actually do with +it because we can't do any decent + + align:start position:0% +it because we can't do any decent + + + align:start position:0% +it because we can't do any decent +analysis but it does tell us because the + + align:start position:0% +analysis but it does tell us because the + + + align:start position:0% +analysis but it does tell us because the +course six are on a large range of + + align:start position:0% +course six are on a large range of + + + align:start position:0% +course six are on a large range of +different spatial scales that we must + + align:start position:0% +different spatial scales that we must + + + align:start position:0% +different spatial scales that we must +have density pertubations inside the + + align:start position:0% +have density pertubations inside the + + + align:start position:0% +have density pertubations inside the +plasma and a lot of different spatial + + align:start position:0% +plasma and a lot of different spatial + + + align:start position:0% +plasma and a lot of different spatial +scales and so this means that plasma is + + align:start position:0% +scales and so this means that plasma is + + + align:start position:0% +scales and so this means that plasma is +likely to be to so this is a little + + align:start position:0% +likely to be to so this is a little + + + align:start position:0% +likely to be to so this is a little +turbulent Z pinch inside a boss P + + align:start position:0% +turbulent Z pinch inside a boss P + + + align:start position:0% +turbulent Z pinch inside a boss P +machine so is that it oh and you can + + align:start position:0% +machine so is that it oh and you can + + + align:start position:0% +machine so is that it oh and you can +also do some pretty good uh 3D mhd + + align:start position:0% +also do some pretty good uh 3D mhd + + + align:start position:0% +also do some pretty good uh 3D mhd +simulations of these things and then you + + align:start position:0% +simulations of these things and then you + + + align:start position:0% +simulations of these things and then you +can spend a lot of time doing multicolor + + align:start position:0% +can spend a lot of time doing multicolor + + + align:start position:0% +can spend a lot of time doing multicolor +R tracing tring Rays through them and + + align:start position:0% +R tracing tring Rays through them and + + + align:start position:0% +R tracing tring Rays through them and +seeing what the shadowy looks like I + + align:start position:0% +seeing what the shadowy looks like I + + + align:start position:0% +seeing what the shadowy looks like I +don't think this is a particularly bad + + align:start position:0% +don't think this is a particularly bad + + + align:start position:0% +don't think this is a particularly bad +match between what we saw from our + + align:start position:0% +match between what we saw from our + + + align:start position:0% +match between what we saw from our +simulations and what we saw our actual + + align:start position:0% +simulations and what we saw our actual + + + align:start position:0% +simulations and what we saw our actual +data here so it is possible to use + + align:start position:0% +data here so it is possible to use + + + align:start position:0% +data here so it is possible to use +computational tools uh to work out what + + align:start position:0% +computational tools uh to work out what + + + align:start position:0% +computational tools uh to work out what +we would predict so that's it that's all + + align:start position:0% +we would predict so that's it that's all + + + align:start position:0% +we would predict so that's it that's all +I've got on shogy and SCH any questions + + align:start position:0% +I've got on shogy and SCH any questions + + + align:start position:0% +I've got on shogy and SCH any questions +on that yeah even in case have Cs and no + + align:start position:0% +on that yeah even in case have Cs and no + + + align:start position:0% +on that yeah even in case have Cs and no +feeling get all the way back to initial + + align:start position:0% +feeling get all the way back to initial + + + align:start position:0% +feeling get all the way back to initial +distribution can you at least analyze it + + align:start position:0% +distribution can you at least analyze it + + + align:start position:0% +distribution can you at least analyze it +for like frequency distribution or + + align:start position:0% +for like frequency distribution or + + + align:start position:0% +for like frequency distribution or +something to get like oh I must have had + + align:start position:0% +something to get like oh I must have had + + + align:start position:0% +something to get like oh I must have had +this spatial scales my original plasma + + align:start position:0% +this spatial scales my original plasma + + + align:start position:0% +this spatial scales my original plasma +or something like yeah so it's very + + align:start position:0% +or something like yeah so it's very + + + align:start position:0% +or something like yeah so it's very +tempting when you have an image or when + + align:start position:0% +tempting when you have an image or when + + + align:start position:0% +tempting when you have an image or when +you have a a Time series bit of data to + + align:start position:0% +you have a a Time series bit of data to + + + align:start position:0% +you have a a Time series bit of data to +for transform it and like look for + + align:start position:0% +for transform it and like look for + + + align:start position:0% +for transform it and like look for +spectral content and in particular when + + align:start position:0% +spectral content and in particular when + + + align:start position:0% +spectral content and in particular when +we're talking about turbulence we might + + align:start position:0% +we're talking about turbulence we might + + + align:start position:0% +we're talking about turbulence we might +do that we might look for like power + + align:start position:0% +do that we might look for like power + + + align:start position:0% +do that we might look for like power +Spectra corresponding to some turbulent + + align:start position:0% +Spectra corresponding to some turbulent + + + align:start position:0% +Spectra corresponding to some turbulent +density fluctuation Spectrum so like + + align:start position:0% +density fluctuation Spectrum so like + + + align:start position:0% +density fluctuation Spectrum so like +Comm Off K to minus + + align:start position:0% +Comm Off K to minus + + + align:start position:0% +Comm Off K to minus +53 so I did this um I I did this and of + + align:start position:0% +53 so I did this um I I did this and of + + + align:start position:0% +53 so I did this um I I did this and of +course you get a really nice K to the + + align:start position:0% +course you get a really nice K to the + + + align:start position:0% +course you get a really nice K to the +minus 53s on this then I took the + + align:start position:0% +minus 53s on this then I took the + + + align:start position:0% +minus 53s on this then I took the +background image the one without the + + align:start position:0% +background image the one without the + + + align:start position:0% +background image the one without the +plasma and you also get Kus 5/3 and then + + align:start position:0% +plasma and you also get Kus 5/3 and then + + + align:start position:0% +plasma and you also get Kus 5/3 and then +I took a photograph of the experimental + + align:start position:0% +I took a photograph of the experimental + + + align:start position:0% +I took a photograph of the experimental +apparatus and for transform the + + align:start position:0% +apparatus and for transform the + + + align:start position:0% +apparatus and for transform the +photograph and you also get something + + align:start position:0% +photograph and you also get something + + + align:start position:0% +photograph and you also get something +like K to minus 53 the trouble is when + + align:start position:0% +like K to minus 53 the trouble is when + + + align:start position:0% +like K to minus 53 the trouble is when +you're doing foro transforms on images + + align:start position:0% +you're doing foro transforms on images + + + align:start position:0% +you're doing foro transforms on images +you've got to think how many pixels I've + + align:start position:0% +you've got to think how many pixels I've + + + align:start position:0% +you've got to think how many pixels I've +got you probably got like a thousand by + + align:start position:0% +got you probably got like a thousand by + + + align:start position:0% +got you probably got like a thousand by +a thousand pixels and so when you're + + align:start position:0% +a thousand pixels and so when you're + + + align:start position:0% +a thousand pixels and so when you're +doing your foro transform your dynamic + + align:start position:0% +doing your foro transform your dynamic + + + align:start position:0% +doing your foro transform your dynamic +range is only going to be about 10 plus + + align:start position:0% +range is only going to be about 10 plus + + + align:start position:0% +range is only going to be about 10 plus +three but at those large scales at the + + align:start position:0% +three but at those large scales at the + + + align:start position:0% +three but at those large scales at the +the the smallest K it's going to be like + + align:start position:0% +the the smallest K it's going to be like + + + align:start position:0% +the the smallest K it's going to be like +large scale structure so you wouldn't + + align:start position:0% +large scale structure so you wouldn't + + + align:start position:0% +large scale structure so you wouldn't +fit a power Spectrum there and at small + + align:start position:0% +fit a power Spectrum there and at small + + + align:start position:0% +fit a power Spectrum there and at small +scales it's going to be down at pixel + + align:start position:0% +scales it's going to be down at pixel + + + align:start position:0% +scales it's going to be down at pixel +noise so you wouldn't fit it there so + + align:start position:0% +noise so you wouldn't fit it there so + + + align:start position:0% +noise so you wouldn't fit it there so +actually you've only got maybe an order + + align:start position:0% +actually you've only got maybe an order + + + align:start position:0% +actually you've only got maybe an order +of magnitude and you can fit any + + align:start position:0% +of magnitude and you can fit any + + + align:start position:0% +of magnitude and you can fit any +straight line you want to a curve and + + align:start position:0% +straight line you want to a curve and + + + align:start position:0% +straight line you want to a curve and +claim that you've got Kus 5/3 or k to + + align:start position:0% +claim that you've got Kus 5/3 or k to + + + align:start position:0% +claim that you've got Kus 5/3 or k to +Theus three halves or whatever because + + align:start position:0% +Theus three halves or whatever because + + + align:start position:0% +Theus three halves or whatever because +when you do turbulence Theory they all + + align:start position:0% +when you do turbulence Theory they all + + + align:start position:0% +when you do turbulence Theory they all +turn out to be roughly the same so + + align:start position:0% +turn out to be roughly the same so + + + align:start position:0% +turn out to be roughly the same so +that's one reason it's really hard to + + align:start position:0% +that's one reason it's really hard to + + + align:start position:0% +that's one reason it's really hard to +just the for transform these the second + + align:start position:0% +just the for transform these the second + + + align:start position:0% +just the for transform these the second +reason is as we talked about before this + + align:start position:0% +reason is as we talked about before this + + + align:start position:0% +reason is as we talked about before this +is a mirage it's not an image so if I + + align:start position:0% +is a mirage it's not an image so if I + + + align:start position:0% +is a mirage it's not an image so if I +see a region like this black region here + + align:start position:0% +see a region like this black region here + + + align:start position:0% +see a region like this black region here +or another region maybe it's easier to + + align:start position:0% +or another region maybe it's easier to + + + align:start position:0% +or another region maybe it's easier to +point out on this one you know you see + + align:start position:0% +point out on this one you know you see + + + align:start position:0% +point out on this one you know you see +these sort of black voids here and you + + align:start position:0% +these sort of black voids here and you + + + align:start position:0% +these sort of black voids here and you +think okay I could just be like hey this + + align:start position:0% +think okay I could just be like hey this + + + align:start position:0% +think okay I could just be like hey this +is about 2 millimeters long this is one + + align:start position:0% +is about 2 millimeters long this is one + + + align:start position:0% +is about 2 millimeters long this is one +millimeter long make a histogram fit a + + align:start position:0% +millimeter long make a histogram fit a + + + align:start position:0% +millimeter long make a histogram fit a +power or something to it but these don't + + align:start position:0% +power or something to it but these don't + + + align:start position:0% +power or something to it but these don't +represent an object that is 2 + + align:start position:0% +represent an object that is 2 + + + align:start position:0% +represent an object that is 2 +millimeters long they are a defocusing + + align:start position:0% +millimeters long they are a defocusing + + + align:start position:0% +millimeters long they are a defocusing +mechanism that could be a really tiny + + align:start position:0% +mechanism that could be a really tiny + + + align:start position:0% +mechanism that could be a really tiny +region of very high density that + + align:start position:0% +region of very high density that + + + align:start position:0% +region of very high density that +defocuses and then it's projected out + + align:start position:0% +defocuses and then it's projected out + + + align:start position:0% +defocuses and then it's projected out +into this larger region so we can't + + align:start position:0% +into this larger region so we can't + + + align:start position:0% +into this larger region so we can't +there's no spatial information properly + + align:start position:0% +there's no spatial information properly + + + align:start position:0% +there's no spatial information properly +left inside this image there's some + + align:start position:0% +left inside this image there's some + + + align:start position:0% +left inside this image there's some +spatial imation you know this this sort + + align:start position:0% +spatial imation you know this this sort + + + align:start position:0% +spatial imation you know this this sort +of structure here corresponds to this + + align:start position:0% +of structure here corresponds to this + + + align:start position:0% +of structure here corresponds to this +sort of structure and you think it's + + align:start position:0% +sort of structure and you think it's + + + align:start position:0% +sort of structure and you think it's +about 5 millimeters across it's probably + + align:start position:0% +about 5 millimeters across it's probably + + + align:start position:0% +about 5 millimeters across it's probably +slightly demagnified because it will + + align:start position:0% +slightly demagnified because it will + + + align:start position:0% +slightly demagnified because it will +actually make a a larger image um but + + align:start position:0% +actually make a a larger image um but + + + align:start position:0% +actually make a a larger image um but +each of these individual voids no longer + + align:start position:0% +each of these individual voids no longer + + + align:start position:0% +each of these individual voids no longer +has the same spatial size as the + + align:start position:0% +has the same spatial size as the + + + align:start position:0% +has the same spatial size as the +structure that produced it so it's very + + align:start position:0% +structure that produced it so it's very + + + align:start position:0% +structure that produced it so it's very +hard to infer things about + + align:start position:0% +hard to infer things about + + + align:start position:0% +hard to infer things about +terb but yeah it's a good + + align:start position:0% +terb but yeah it's a good + + + align:start position:0% +terb but yeah it's a good +question any other questions + + align:start position:0% + + + + align:start position:0% + +even though + + align:start position:0% +even though + + + align:start position:0% +even though +like + + align:start position:0% + + + + align:start position:0% + +get so I don't think you can I mean when + + align:start position:0% +get so I don't think you can I mean when + + + align:start position:0% +get so I don't think you can I mean when +you run this algorithm on your data shog + + align:start position:0% +you run this algorithm on your data shog + + + align:start position:0% +you run this algorithm on your data shog +graphy or proton radiography one of + + align:start position:0% +graphy or proton radiography one of + + + align:start position:0% +graphy or proton radiography one of +these mamp optimal transer alth it will + + align:start position:0% +these mamp optimal transer alth it will + + + align:start position:0% +these mamp optimal transer alth it will +always give you an answer right so it + + align:start position:0% +always give you an answer right so it + + + align:start position:0% +always give you an answer right so it +returns it returns a solution right but + + align:start position:0% +returns it returns a solution right but + + + align:start position:0% +returns it returns a solution right but +we know that these uh reconstruction + + align:start position:0% +we know that these uh reconstruction + + + align:start position:0% +we know that these uh reconstruction +alems don't work when we have the coost + + align:start position:0% +alems don't work when we have the coost + + + align:start position:0% +alems don't work when we have the coost +stick regime and so that solution is is + + align:start position:0% +stick regime and so that solution is is + + + align:start position:0% +stick regime and so that solution is is +very suspect right like we don't believe + + align:start position:0% +very suspect right like we don't believe + + + align:start position:0% +very suspect right like we don't believe +we should trust it so I don't think + + align:start position:0% +we should trust it so I don't think + + + align:start position:0% +we should trust it so I don't think +there's anything you can use from that + + align:start position:0% +there's anything you can use from that + + + align:start position:0% +there's anything you can use from that +solution to help you reconstruct the + + align:start position:0% +solution to help you reconstruct the + + + align:start position:0% +solution to help you reconstruct the +actual thing I think at that point if + + align:start position:0% +actual thing I think at that point if + + + align:start position:0% +actual thing I think at that point if +you've got cor sticks your best bet is + + align:start position:0% +you've got cor sticks your best bet is + + + align:start position:0% +you've got cor sticks your best bet is +having some very strong priers as to the + + align:start position:0% +having some very strong priers as to the + + + align:start position:0% +having some very strong priers as to the +sort of plasma you think you've got and + + align:start position:0% +sort of plasma you think you've got and + + + align:start position:0% +sort of plasma you think you've got and +then pushing Monte Carlo Rays or protons + + align:start position:0% +then pushing Monte Carlo Rays or protons + + + align:start position:0% +then pushing Monte Carlo Rays or protons +through it doing the forward problem and + + align:start position:0% +through it doing the forward problem and + + + align:start position:0% +through it doing the forward problem and +adjusting the forward problem until it + + align:start position:0% +adjusting the forward problem until it + + + align:start position:0% +adjusting the forward problem until it +matches some of the features you see on + + align:start position:0% +matches some of the features you see on + + + align:start position:0% +matches some of the features you see on +your actual data I don't think you can + + align:start position:0% +your actual data I don't think you can + + + align:start position:0% +your actual data I don't think you can +do the inverse problem easly but there + + align:start position:0% +do the inverse problem easly but there + + + align:start position:0% +do the inverse problem easly but there +have been a few papers where people have + + align:start position:0% +have been a few papers where people have + + + align:start position:0% +have been a few papers where people have +tried to do this because we almost + + align:start position:0% +tried to do this because we almost + + + align:start position:0% +tried to do this because we almost +always end up in the costic regime so + + align:start position:0% +always end up in the costic regime so + + + align:start position:0% +always end up in the costic regime so +people have all this data and they want + + align:start position:0% +people have all this data and they want + + + align:start position:0% +people have all this data and they want +to use it like it's reasonable to try + + align:start position:0% +to use it like it's reasonable to try + + + align:start position:0% +to use it like it's reasonable to try +and do something with that data it's + + align:start position:0% +and do something with that data it's + + + align:start position:0% +and do something with that data it's +just very hard so + + align:start position:0% +just very hard so + + + align:start position:0% +just very hard so +yeah yeah so for this images of like the + + align:start position:0% +yeah yeah so for this images of like the + + + align:start position:0% +yeah yeah so for this images of like the +heads and like the room those are not + + align:start position:0% +heads and like the room those are not + + + align:start position:0% +heads and like the room those are not +super small scale effects so to see + + align:start position:0% +super small scale effects so to see + + + align:start position:0% +super small scale effects so to see +those you just push your Imaging surface + + align:start position:0% +those you just push your Imaging surface + + + align:start position:0% +those you just push your Imaging surface +really far away if you take a laser + + align:start position:0% +really far away if you take a laser + + + align:start position:0% +really far away if you take a laser +pointer uh and make it diverge by taking + + align:start position:0% +pointer uh and make it diverge by taking + + + align:start position:0% +pointer uh and make it diverge by taking +off the little lens at the front of it + + align:start position:0% +off the little lens at the front of it + + + align:start position:0% +off the little lens at the front of it +and you take a candle flame and you + + align:start position:0% +and you take a candle flame and you + + + align:start position:0% +and you take a candle flame and you +project it onto a wall you will see this + + align:start position:0% +project it onto a wall you will see this + + + align:start position:0% +project it onto a wall you will see this +like again you know you see Mires just + + align:start position:0% +like again you know you see Mires just + + + align:start position:0% +like again you know you see Mires just +using sunlight so yeah this not a hard + + align:start position:0% +using sunlight so yeah this not a hard + + + align:start position:0% +using sunlight so yeah this not a hard +thing to observe so if you see something + + align:start position:0% +thing to observe so if you see something + + + align:start position:0% +thing to observe so if you see something +with your naked eye it's either like a + + align:start position:0% +with your naked eye it's either like a + + + align:start position:0% +with your naked eye it's either like a +really small or something far away yes + + align:start position:0% +really small or something far away yes + + + align:start position:0% +really small or something far away yes +yes exactly and usually it's quite far + + align:start position:0% +yes exactly and usually it's quite far + + + align:start position:0% +yes exactly and usually it's quite far +away right I mean if we you can often + + align:start position:0% +away right I mean if we you can often + + + align:start position:0% +away right I mean if we you can often +see even the heat rising from like a + + align:start position:0% +see even the heat rising from like a + + + align:start position:0% +see even the heat rising from like a +vent or something like that but not when + + align:start position:0% +vent or something like that but not when + + + align:start position:0% +vent or something like that but not when +you're right up close to it give it a go + + align:start position:0% +you're right up close to it give it a go + + + align:start position:0% +you're right up close to it give it a go +next time you see something if it's + + align:start position:0% +next time you see something if it's + + + align:start position:0% +next time you see something if it's +sayfe put your eye right up next to it + + align:start position:0% +sayfe put your eye right up next to it + + + align:start position:0% +sayfe put your eye right up next to it +it disappears so + + align:start position:0% +it disappears so + + + align:start position:0% +it disappears so +yeah please don't + + align:start position:0% +yeah please don't + + + align:start position:0% +yeah please don't +anyway any other + + align:start position:0% +anyway any other + + + align:start position:0% +anyway any other +questions one more example like when you + + align:start position:0% +questions one more example like when you + + + align:start position:0% +questions one more example like when you +can see like this + + align:start position:0% +can see like this + + + align:start position:0% +can see like this +exact sitation is like if you have + + align:start position:0% +exact sitation is like if you have + + + align:start position:0% +exact sitation is like if you have +sunlight coming through a window and + + align:start position:0% +sunlight coming through a window and + + + align:start position:0% +sunlight coming through a window and +over like a yes on the + + align:start position:0% +over like a yes on the + + + align:start position:0% +over like a yes on the +yes yeah yeah exactly that's thing + + align:start position:0% +yes yeah yeah exactly that's thing + + + align:start position:0% +yes yeah yeah exactly that's thing +another place um the botom a swimming + + align:start position:0% +another place um the botom a swimming + + + align:start position:0% +another place um the botom a swimming +pool so when you have you know waves on + + align:start position:0% +pool so when you have you know waves on + + + align:start position:0% +pool so when you have you know waves on +the top surface of a swimming pool you + + align:start position:0% +the top surface of a swimming pool you + + + align:start position:0% +the top surface of a swimming pool you +get those bright lines on the bottom + + align:start position:0% +get those bright lines on the bottom + + + align:start position:0% +get those bright lines on the bottom +those are coost stics right so exactly + + align:start position:0% +those are coost stics right so exactly + + + align:start position:0% +those are coost stics right so exactly +the same sort of physics is produces + + align:start position:0% +the same sort of physics is produces + + + align:start position:0% +the same sort of physics is produces +these there is a beautiful book called + + align:start position:0% +these there is a beautiful book called + + + align:start position:0% +these there is a beautiful book called +The Natural focusing of Light which + + align:start position:0% +The Natural focusing of Light which + + + align:start position:0% +The Natural focusing of Light which +tries to analyze cotic but mostly does + + align:start position:0% +tries to analyze cotic but mostly does + + + align:start position:0% +tries to analyze cotic but mostly does +it in a way that I don't think it's + + align:start position:0% +it in a way that I don't think it's + + + align:start position:0% +it in a way that I don't think it's +practical it's theoretically beautiful + + align:start position:0% +practical it's theoretically beautiful + + + align:start position:0% +practical it's theoretically beautiful +um and one of the things that they point + + align:start position:0% +um and one of the things that they point + + + align:start position:0% +um and one of the things that they point +out about cors is where every time you + + align:start position:0% +out about cors is where every time you + + + align:start position:0% +out about cors is where every time you +get a bright region you get like a dark + + align:start position:0% +get a bright region you get like a dark + + + align:start position:0% +get a bright region you get like a dark +region on one side but not on the other + + align:start position:0% +region on one side but not on the other + + + align:start position:0% +region on one side but not on the other +side and that tells you like what + + align:start position:0% +side and that tells you like what + + + align:start position:0% +side and that tells you like what +direction the cor stick came from from + + align:start position:0% +direction the cor stick came from from + + + align:start position:0% +direction the cor stick came from from +and so you might be able to trace back a + + align:start position:0% +and so you might be able to trace back a + + + align:start position:0% +and so you might be able to trace back a +series of arrows around one of these cor + + align:start position:0% +series of arrows around one of these cor + + + align:start position:0% +series of arrows around one of these cor +sticks here and work out where the point + + align:start position:0% +sticks here and work out where the point + + + align:start position:0% +sticks here and work out where the point +was that the cor stick originated but + + align:start position:0% +was that the cor stick originated but + + + align:start position:0% +was that the cor stick originated but +it's very tricky to do the analysis of + + align:start position:0% +it's very tricky to do the analysis of + + + align:start position:0% +it's very tricky to do the analysis of +it but the point is the book is called + + align:start position:0% +it but the point is the book is called + + + align:start position:0% +it but the point is the book is called +the natural focusing of light so people + + align:start position:0% +the natural focusing of light so people + + + align:start position:0% +the natural focusing of light so people +refer to this field as natural focusing + + align:start position:0% +refer to this field as natural focusing + + + align:start position:0% +refer to this field as natural focusing +no one has tried to make a lens no one + + align:start position:0% +no one has tried to make a lens no one + + + align:start position:0% +no one has tried to make a lens no one +is trying to do any focusing our medium + + align:start position:0% +is trying to do any focusing our medium + + + align:start position:0% +is trying to do any focusing our medium +with its in homogeneous reflective index + + align:start position:0% +with its in homogeneous reflective index + + + align:start position:0% +with its in homogeneous reflective index +has just done it for us then we might + + align:start position:0% +has just done it for us then we might + + + align:start position:0% +has just done it for us then we might +try and work out what we can learn about + + align:start position:0% +try and work out what we can learn about + + + align:start position:0% +try and work out what we can learn about +the medium from looking at the light + + align:start position:0% +the medium from looking at the light + + + align:start position:0% +the medium from looking at the light +that's gone through + + align:start position:0% + + + + align:start position:0% + +yes one more thing to make sure I try + + align:start position:0% +yes one more thing to make sure I try + + + align:start position:0% +yes one more thing to make sure I try +this + + align:start position:0% +this + + + align:start position:0% +this +later so if you have an image like the + + align:start position:0% +later so if you have an image like the + + + align:start position:0% +later so if you have an image like the +one with the board for instance like + + align:start position:0% +one with the board for instance like + + + align:start position:0% +one with the board for instance like +there are some really clear to Sticks + + align:start position:0% +there are some really clear to Sticks + + + align:start position:0% +there are some really clear to Sticks +then and parts of the rest of the image + + align:start position:0% +then and parts of the rest of the image + + + align:start position:0% +then and parts of the rest of the image +look like they might be + + align:start position:0% +look like they might be + + + align:start position:0% +look like they might be +fine if you want to analyze the rest of + + align:start position:0% +fine if you want to analyze the rest of + + + align:start position:0% +fine if you want to analyze the rest of +your image is that oh yeah you can cut + + align:start position:0% +your image is that oh yeah you can cut + + + align:start position:0% +your image is that oh yeah you can cut +out the bit with the co sticks yeah yeah + + align:start position:0% +out the bit with the co sticks yeah yeah + + + align:start position:0% +out the bit with the co sticks yeah yeah +that's fine so I mean almost none of + + align:start position:0% +that's fine so I mean almost none of + + + align:start position:0% +that's fine so I mean almost none of +this image is actually suitable but like + + align:start position:0% +this image is actually suitable but like + + + align:start position:0% +this image is actually suitable but like +maybe this bit would be more because + + align:start position:0% +maybe this bit would be more because + + + align:start position:0% +maybe this bit would be more because +it's not small intensity variations you + + align:start position:0% +it's not small intensity variations you + + + align:start position:0% +it's not small intensity variations you +can see if you think about this gray as + + align:start position:0% +can see if you think about this gray as + + + align:start position:0% +can see if you think about this gray as +like .5 and you think about the white as + + align:start position:0% +like .5 and you think about the white as + + + align:start position:0% +like .5 and you think about the white as +one and the black as zero you can see + + align:start position:0% +one and the black as zero you can see + + + align:start position:0% +one and the black as zero you can see +that you're getting modulations on the + + align:start position:0% +that you're getting modulations on the + + + align:start position:0% +that you're getting modulations on the +order of 0.5 inside this image so it's + + align:start position:0% +order of 0.5 inside this image so it's + + + align:start position:0% +order of 0.5 inside this image so it's +clearly not in that small regime but + + align:start position:0% +clearly not in that small regime but + + + align:start position:0% +clearly not in that small regime but +it's not clear that these the coost + + align:start position:0% +it's not clear that these the coost + + + align:start position:0% +it's not clear that these the coost +stics so you may still be able to use + + align:start position:0% +stics so you may still be able to use + + + align:start position:0% +stics so you may still be able to use +one of the complicated mamp like style + + align:start position:0% +one of the complicated mamp like style + + + align:start position:0% +one of the complicated mamp like style +reconstruction techniques you just won't + + align:start position:0% +reconstruction techniques you just won't + + + align:start position:0% +reconstruction techniques you just won't +be able to use the nice formula that we + + align:start position:0% +be able to use the nice formula that we + + + align:start position:0% +be able to use the nice formula that we +wrote down analytically so + + align:start position:0% + + + + align:start position:0% + +okay you've successfully timed me out I + + align:start position:0% +okay you've successfully timed me out I + + + align:start position:0% +okay you've successfully timed me out I +was going to start to go inry well done + + align:start position:0% +was going to start to go inry well done + + + align:start position:0% +was going to start to go inry well done +everyone so we'll leave it there and we + + align:start position:0% +everyone so we'll leave it there and we + + + align:start position:0% +everyone so we'll leave it there and we +will pick up on infmetry on uh Thursday + + align:start position:0% +will pick up on infmetry on uh Thursday + + + align:start position:0% +will pick up on infmetry on uh Thursday +so \ No newline at end of file diff --git a/WguhC64iAXI.txt b/WguhC64iAXI.txt new file mode 100644 index 0000000000000000000000000000000000000000..598d92f53ccde1cb896c4b20ac678a5344761e54 --- /dev/null +++ b/WguhC64iAXI.txt @@ -0,0 +1,1875 @@ +align:start position:0% + +the first project for the semester was + + align:start position:0% +the first project for the semester was + + + align:start position:0% +the first project for the semester was +designing a outside place in a Quarry + + align:start position:0% +designing a outside place in a Quarry + + + align:start position:0% +designing a outside place in a Quarry +North of Boston in + + align:start position:0% +North of Boston in + + + align:start position:0% +North of Boston in +Rockport we have gone to the Quarry and + + align:start position:0% +Rockport we have gone to the Quarry and + + + align:start position:0% +Rockport we have gone to the Quarry and +they were asked the students were asked + + align:start position:0% +they were asked the students were asked + + + align:start position:0% +they were asked the students were asked +to to find a place in the Quarry that + + align:start position:0% +to to find a place in the Quarry that + + + align:start position:0% +to to find a place in the Quarry that +they liked photograph it sketch it + + align:start position:0% +they liked photograph it sketch it + + + align:start position:0% +they liked photograph it sketch it +understand it bring it back to the + + align:start position:0% +understand it bring it back to the + + + align:start position:0% +understand it bring it back to the +studio and then design a + + align:start position:0% +studio and then design a + + + align:start position:0% +studio and then design a +classroom for themselves and + + align:start position:0% +classroom for themselves and + + + align:start position:0% +classroom for themselves and +me uh that was sheltered not + + align:start position:0% +me uh that was sheltered not + + + align:start position:0% +me uh that was sheltered not +enclosed but was the idea was making a + + align:start position:0% +enclosed but was the idea was making a + + + align:start position:0% +enclosed but was the idea was making a +place in the Quarry that was neither + + align:start position:0% +place in the Quarry that was neither + + + align:start position:0% +place in the Quarry that was neither +natural or was it to be appear to be + + align:start position:0% +natural or was it to be appear to be + + + align:start position:0% +natural or was it to be appear to be +built it was to fit into the context of + + align:start position:0% +built it was to fit into the context of + + + align:start position:0% +built it was to fit into the context of +the + + align:start position:0% +the + + + align:start position:0% +the +Quarry um they were welcome to use any + + align:start position:0% +Quarry um they were welcome to use any + + + align:start position:0% +Quarry um they were welcome to use any +materials that they thought would relate + + align:start position:0% +materials that they thought would relate + + + align:start position:0% +materials that they thought would relate +to the + + align:start position:0% +to the + + + align:start position:0% +to the +Quarry when they came back from the + + align:start position:0% +Quarry when they came back from the + + + align:start position:0% +Quarry when they came back from the +Quarry I then asked them to do their + + align:start position:0% +Quarry I then asked them to do their + + + align:start position:0% +Quarry I then asked them to do their +first design and their first ideas of + + align:start position:0% +first design and their first ideas of + + + align:start position:0% +first design and their first ideas of +the + + align:start position:0% +the + + + align:start position:0% +the +Quarry so what you're about to see is + + align:start position:0% +Quarry so what you're about to see is + + + align:start position:0% +Quarry so what you're about to see is +the very first pinup of the semester of + + align:start position:0% +the very first pinup of the semester of + + + align:start position:0% +the very first pinup of the semester of +this very first project + + align:start position:0% + + + + align:start position:0% + +so what I um saw that um was the best + + align:start position:0% +so what I um saw that um was the best + + + align:start position:0% +so what I um saw that um was the best +about this night was um how nature is + + align:start position:0% +about this night was um how nature is + + + align:start position:0% +about this night was um how nature is +really um it it it's got a logic to it + + align:start position:0% +really um it it it's got a logic to it + + + align:start position:0% +really um it it it's got a logic to it +and every Gap and everything that that + + align:start position:0% +and every Gap and everything that that + + + align:start position:0% +and every Gap and everything that that +is there it's still been in some ways + + align:start position:0% +is there it's still been in some ways + + + align:start position:0% +is there it's still been in some ways +there's nothing lost there's nothing + + align:start position:0% +there's nothing lost there's nothing + + + align:start position:0% +there's nothing lost there's nothing +nothing wasted everything sort of + + align:start position:0% +nothing wasted everything sort of + + + align:start position:0% +nothing wasted everything sort of +belongs in that sort of net of things + + align:start position:0% +belongs in that sort of net of things + + + align:start position:0% +belongs in that sort of net of things +and um so when I I decided that my site + + align:start position:0% +and um so when I I decided that my site + + + align:start position:0% +and um so when I I decided that my site +would be right here where the seagull + + align:start position:0% +would be right here where the seagull + + + align:start position:0% +would be right here where the seagull +were um I figured that the seagull would + + align:start position:0% +were um I figured that the seagull would + + + align:start position:0% +were um I figured that the seagull would +know better than me what the best place + + align:start position:0% +know better than me what the best place + + + align:start position:0% +know better than me what the best place +was um since Nature has that logic um so + + align:start position:0% +was um since Nature has that logic um so + + + align:start position:0% +was um since Nature has that logic um so +the animals did too and + + align:start position:0% +the animals did too and + + + align:start position:0% +the animals did too and +um you know I realiz they lik about the + + align:start position:0% +um you know I realiz they lik about the + + + align:start position:0% +um you know I realiz they lik about the +site um but if you notice it's got a lot + + align:start position:0% +site um but if you notice it's got a lot + + + align:start position:0% +site um but if you notice it's got a lot +of um it's it basically is a cliff sort + + align:start position:0% +of um it's it basically is a cliff sort + + + align:start position:0% +of um it's it basically is a cliff sort +of cutout and what I'm trying to do is + + align:start position:0% +of cutout and what I'm trying to do is + + + align:start position:0% +of cutout and what I'm trying to do is +fill that space as nature does just have + + align:start position:0% +fill that space as nature does just have + + + align:start position:0% +fill that space as nature does just have +that space fill in um and and this is + + align:start position:0% +that space fill in um and and this is + + + align:start position:0% +that space fill in um and and this is +what the site looks like now um they're + + align:start position:0% +what the site looks like now um they're + + + align:start position:0% +what the site looks like now um they're +the + + align:start position:0% +the + + + align:start position:0% +the +seagull um and then this is what I'm + + align:start position:0% +seagull um and then this is what I'm + + + align:start position:0% +seagull um and then this is what I'm +hoping to do is to sort of feel that + + align:start position:0% +hoping to do is to sort of feel that + + + align:start position:0% +hoping to do is to sort of feel that +um to just make it look like how it used + + align:start position:0% +um to just make it look like how it used + + + align:start position:0% +um to just make it look like how it used +to be how I imag it been before when was + + align:start position:0% +to be how I imag it been before when was + + + align:start position:0% +to be how I imag it been before when was +already present + + align:start position:0% +already present + + + align:start position:0% +already present +inag um and I like the idea of just + + align:start position:0% +inag um and I like the idea of just + + + align:start position:0% +inag um and I like the idea of just +throwing those gaps um here it shows + + align:start position:0% +throwing those gaps um here it shows + + + align:start position:0% +throwing those gaps um here it shows +just how even it even the grass and the + + align:start position:0% +just how even it even the grass and the + + + align:start position:0% +just how even it even the grass and the +ground and the soil um evens out the all + + align:start position:0% +ground and the soil um evens out the all + + + align:start position:0% +ground and the soil um evens out the all +the Rocks even though the jacket um so + + align:start position:0% +the Rocks even though the jacket um so + + + align:start position:0% +the Rocks even though the jacket um so +evening things out here this night + + align:start position:0% +evening things out here this night + + + align:start position:0% +evening things out here this night +hoping that I'll just even that out in a + + align:start position:0% +hoping that I'll just even that out in a + + + align:start position:0% +hoping that I'll just even that out in a +way + + align:start position:0% +way + + + align:start position:0% +way +um also I while I was sitting there I + + align:start position:0% +um also I while I was sitting there I + + + align:start position:0% +um also I while I was sitting there I +was um as listen to the seagull and they + + align:start position:0% +was um as listen to the seagull and they + + + align:start position:0% +was um as listen to the seagull and they +were a little bit annoying at times but + + align:start position:0% +were a little bit annoying at times but + + + align:start position:0% +were a little bit annoying at times but +just the sound of the water splashing + + align:start position:0% +just the sound of the water splashing + + + align:start position:0% +just the sound of the water splashing +the sound of them + + align:start position:0% +the sound of them + + + align:start position:0% +the sound of them +um just flying around um the wind + + align:start position:0% +um just flying around um the wind + + + align:start position:0% +um just flying around um the wind +wrestling of all the plants and that was + + align:start position:0% +wrestling of all the plants and that was + + + align:start position:0% +wrestling of all the plants and that was +also part of the experience and um I'm + + align:start position:0% +also part of the experience and um I'm + + + align:start position:0% +also part of the experience and um I'm +hoping the co exist to with the sing I + + align:start position:0% +hoping the co exist to with the sing I + + + align:start position:0% +hoping the co exist to with the sing I +want to this is the site uh looking at + + align:start position:0% +want to this is the site uh looking at + + + align:start position:0% +want to this is the site uh looking at +it Southward + + align:start position:0% +it Southward + + + align:start position:0% +it Southward +um living here uh I saw this small sort + + align:start position:0% +um living here uh I saw this small sort + + + align:start position:0% +um living here uh I saw this small sort +of space here as a private area also in + + align:start position:0% +of space here as a private area also in + + + align:start position:0% +of space here as a private area also in +here as a private area and then this + + align:start position:0% +here as a private area and then this + + + align:start position:0% +here as a private area and then this +bigger space as place um I'm looking at + + align:start position:0% +bigger space as place um I'm looking at + + + align:start position:0% +bigger space as place um I'm looking at +the studio as more of a dynamic Place + + align:start position:0% +the studio as more of a dynamic Place + + + align:start position:0% +the studio as more of a dynamic Place +rather than all of us having our desks + + align:start position:0% +rather than all of us having our desks + + + align:start position:0% +rather than all of us having our desks +um this is my idea is adding a stone + + align:start position:0% +um this is my idea is adding a stone + + + align:start position:0% +um this is my idea is adding a stone +wall to the side so that it Blends and I + + align:start position:0% +wall to the side so that it Blends and I + + + align:start position:0% +wall to the side so that it Blends and I +I just I'm very literal about um I just + + align:start position:0% +I just I'm very literal about um I just + + + align:start position:0% +I just I'm very literal about um I just +imagine these trees just growing out of + + align:start position:0% +imagine these trees just growing out of + + + align:start position:0% +imagine these trees just growing out of +those gaps in the rocks and um making a + + align:start position:0% +those gaps in the rocks and um making a + + + align:start position:0% +those gaps in the rocks and um making a +canopy and intertwining in the top and + + align:start position:0% +canopy and intertwining in the top and + + + align:start position:0% +canopy and intertwining in the top and +um sort of like how when we entered the + + align:start position:0% +um sort of like how when we entered the + + + align:start position:0% +um sort of like how when we entered the +space there we came in this like T of + + align:start position:0% +space there we came in this like T of + + + align:start position:0% +space there we came in this like T of +just like canopy of plant um that's sort + + align:start position:0% +just like canopy of plant um that's sort + + + align:start position:0% +just like canopy of plant um that's sort +of what I want to do that that lip of of + + align:start position:0% +of what I want to do that that lip of of + + + align:start position:0% +of what I want to do that that lip of of +plants and people sitting around uh with + + align:start position:0% +plants and people sitting around uh with + + + align:start position:0% +plants and people sitting around uh with +their drawing boards on the LPS moving + + align:start position:0% +their drawing boards on the LPS moving + + + align:start position:0% +their drawing boards on the LPS moving +around going down here to look out + + align:start position:0% + + + + align:start position:0% + +um uh here is my model + + align:start position:0% +um uh here is my model + + + align:start position:0% +um uh here is my model +um I was thinking of St on the side and + + align:start position:0% +um I was thinking of St on the side and + + + align:start position:0% +um I was thinking of St on the side and +then going all the way down um + + align:start position:0% +then going all the way down um + + + align:start position:0% +then going all the way down um +but add steps from one space the other + + align:start position:0% +but add steps from one space the other + + + align:start position:0% +but add steps from one space the other +but what did you just take away um these + + align:start position:0% +but what did you just take away um these + + + align:start position:0% +but what did you just take away um these +were the stats oh + + align:start position:0% +were the stats oh + + + align:start position:0% +were the stats oh +okay um well I could take out all the + + align:start position:0% +okay um well I could take out all the + + + align:start position:0% +okay um well I could take out all the +pieces and how you see the original but + + align:start position:0% +pieces and how you see the original but + + + align:start position:0% +pieces and how you see the original but +basically I added the stone walls um and + + align:start position:0% +basically I added the stone walls um and + + + align:start position:0% +basically I added the stone walls um and +I'm thinking I'm using I I I don't feel + + align:start position:0% +I'm thinking I'm using I I I don't feel + + + align:start position:0% +I'm thinking I'm using I I I don't feel +like I want to disturb the environment I + + align:start position:0% +like I want to disturb the environment I + + + align:start position:0% +like I want to disturb the environment I +feel like I want to use what's already + + align:start position:0% +feel like I want to use what's already + + + align:start position:0% +feel like I want to use what's already +there that sort of the the space is + + align:start position:0% +there that sort of the the space is + + + align:start position:0% +there that sort of the the space is +telling me this is useful you know use + + align:start position:0% +telling me this is useful you know use + + + align:start position:0% +telling me this is useful you know use +me as such this is a sitting a sitting + + align:start position:0% +me as such this is a sitting a sitting + + + align:start position:0% +me as such this is a sitting a sitting +area um that is a drawing board this is + + align:start position:0% +area um that is a drawing board this is + + + align:start position:0% +area um that is a drawing board this is +a drawing board um I I don't want I I + + align:start position:0% +a drawing board um I I don't want I I + + + align:start position:0% +a drawing board um I I don't want I I +feel like I can just work with what I + + align:start position:0% +feel like I can just work with what I + + + align:start position:0% +feel like I can just work with what I +have fill that space in um and and not + + align:start position:0% +have fill that space in um and and not + + + align:start position:0% +have fill that space in um and and not +disturb anyone none of the animals nor + + align:start position:0% +disturb anyone none of the animals nor + + + align:start position:0% +disturb anyone none of the animals nor +life can you just talk a little bit + + align:start position:0% +life can you just talk a little bit + + + align:start position:0% +life can you just talk a little bit +about that because it's quite different + + align:start position:0% +about that because it's quite different + + + align:start position:0% +about that because it's quite different +it looks quite different than your + + align:start position:0% +it looks quite different than your + + + align:start position:0% +it looks quite different than your +sketch okay well this is sort of the + + align:start position:0% +sketch okay well this is sort of the + + + align:start position:0% +sketch okay well this is sort of the +abstract version of the sketch um since + + align:start position:0% +abstract version of the sketch um since + + + align:start position:0% +abstract version of the sketch um since +the the spot that I picked is going to + + align:start position:0% +the the spot that I picked is going to + + + align:start position:0% +the the spot that I picked is going to +be very sunny um I wanted to take + + align:start position:0% +be very sunny um I wanted to take + + + align:start position:0% +be very sunny um I wanted to take +advantage of that so um I want something + + align:start position:0% +advantage of that so um I want something + + + align:start position:0% +advantage of that so um I want something +that that will be clear but also create + + align:start position:0% +that that will be clear but also create + + + align:start position:0% +that that will be clear but also create +some some Shadow some movement to um and + + align:start position:0% +some some Shadow some movement to um and + + + align:start position:0% +some some Shadow some movement to um and +in some ways I'm trying to use this as a + + align:start position:0% +in some ways I'm trying to use this as a + + + align:start position:0% +in some ways I'm trying to use this as a +tunnel um on this side and maybe on here + + align:start position:0% +tunnel um on this side and maybe on here + + + align:start position:0% +tunnel um on this side and maybe on here +S A curvature of the roof so that it + + align:start position:0% +S A curvature of the roof so that it + + + align:start position:0% +S A curvature of the roof so that it +trashs light in and BR into the space + + align:start position:0% +trashs light in and BR into the space + + + align:start position:0% +trashs light in and BR into the space +and it might bounce off from the top and + + align:start position:0% +and it might bounce off from the top and + + + align:start position:0% +and it might bounce off from the top and +go down um into the studio + + align:start position:0% +go down um into the studio + + + align:start position:0% +go down um into the studio +um but I just imagine it just growing + + align:start position:0% +um but I just imagine it just growing + + + align:start position:0% +um but I just imagine it just growing +out of the ground just covering it up + + align:start position:0% + + + + align:start position:0% + +again it's a very very good start and + + align:start position:0% +again it's a very very good start and + + + align:start position:0% +again it's a very very good start and +then that gives me a license to negative + + align:start position:0% +then that gives me a license to negative + + + align:start position:0% +then that gives me a license to negative +now that I've done + + align:start position:0% +now that I've done + + + align:start position:0% +now that I've done +Sor um I'm really impressed also how + + align:start position:0% +Sor um I'm really impressed also how + + + align:start position:0% +Sor um I'm really impressed also how +quickly we have understood the Quarry + + align:start position:0% +quickly we have understood the Quarry + + + align:start position:0% +quickly we have understood the Quarry +and the subtleties of of the + + align:start position:0% +and the subtleties of of the + + + align:start position:0% +and the subtleties of of the +observations that you + + align:start position:0% +observations that you + + + align:start position:0% +observations that you +made uh I think the idea of coexisting + + align:start position:0% +made uh I think the idea of coexisting + + + align:start position:0% +made uh I think the idea of coexisting +with the Sea Calls is wonderful I don't + + align:start position:0% +with the Sea Calls is wonderful I don't + + + align:start position:0% +with the Sea Calls is wonderful I don't +know how you do that and if you can do + + align:start position:0% +know how you do that and if you can do + + + align:start position:0% +know how you do that and if you can do +that but I have to tell you a story I + + align:start position:0% +that but I have to tell you a story I + + + align:start position:0% +that but I have to tell you a story I +have a little summer house where I was + + align:start position:0% +have a little summer house where I was + + + align:start position:0% +have a little summer house where I was +which uh two uh young deer have decided + + align:start position:0% +which uh two uh young deer have decided + + + align:start position:0% +which uh two uh young deer have decided +as their house oh boy and uh they I was + + align:start position:0% +as their house oh boy and uh they I was + + + align:start position:0% +as their house oh boy and uh they I was +there and they were there and they were + + align:start position:0% +there and they were there and they were + + + align:start position:0% +there and they were there and they were +sort of wondering why why I was there CU + + align:start position:0% +sort of wondering why why I was there CU + + + align:start position:0% +sort of wondering why why I was there CU +I'm they're there more than I'm there + + align:start position:0% +I'm they're there more than I'm there + + + align:start position:0% +I'm they're there more than I'm there +and um we became friends over a couple + + align:start position:0% +and um we became friends over a couple + + + align:start position:0% +and um we became friends over a couple +days the two + + align:start position:0% +days the two + + + align:start position:0% +days the two +FS that SI dogs and you said the word + + align:start position:0% +FS that SI dogs and you said the word + + + align:start position:0% +FS that SI dogs and you said the word +and I said coexist I fig we could live + + align:start position:0% +and I said coexist I fig we could live + + + align:start position:0% +and I said coexist I fig we could live +together so the sensitivity towards the + + align:start position:0% +together so the sensitivity towards the + + + align:start position:0% +together so the sensitivity towards the +seagull which might have more problems + + align:start position:0% +seagull which might have more problems + + + align:start position:0% +seagull which might have more problems +than the deer I don't know in certain + + align:start position:0% +than the deer I don't know in certain + + + align:start position:0% +than the deer I don't know in certain +ways is wonderful and how you do that I + + align:start position:0% +ways is wonderful and how you do that I + + + align:start position:0% +ways is wonderful and how you do that I +don't know + + align:start position:0% +don't know + + + align:start position:0% +don't know +one is very interesting to me again from + + align:start position:0% +one is very interesting to me again from + + + align:start position:0% +one is very interesting to me again from +the + + align:start position:0% +the + + + align:start position:0% +the +observation of the seall place I think + + align:start position:0% +observation of the seall place I think + + + align:start position:0% +observation of the seall place I think +you're right I think the sealls know + + align:start position:0% +you're right I think the sealls know + + + align:start position:0% +you're right I think the sealls know +something that they they know more than + + align:start position:0% +something that they they know more than + + + align:start position:0% +something that they they know more than +we know they've been around I don't know + + align:start position:0% +we know they've been around I don't know + + + align:start position:0% +we know they've been around I don't know +again how happy they're going to be + + align:start position:0% +again how happy they're going to be + + + align:start position:0% +again how happy they're going to be +about you moving in that's they'll let + + align:start position:0% +about you moving in that's they'll let + + + align:start position:0% +about you moving in that's they'll let +you know + + align:start position:0% +you know + + + align:start position:0% +you know +think uh but I think it's a very good + + align:start position:0% +think uh but I think it's a very good + + + align:start position:0% +think uh but I think it's a very good +observation that this is a natural kind + + align:start position:0% +observation that this is a natural kind + + + align:start position:0% +observation that this is a natural kind +of + + align:start position:0% +of + + + align:start position:0% +of +place + + align:start position:0% +place + + + align:start position:0% +place +some um the trans trans ation of that + + align:start position:0% +some um the trans trans ation of that + + + align:start position:0% +some um the trans trans ation of that +into what you say which is the case with + + align:start position:0% +into what you say which is the case with + + + align:start position:0% +into what you say which is the case with +all of us in the beginning as Architects + + align:start position:0% +all of us in the beginning as Architects + + + align:start position:0% +all of us in the beginning as Architects +and what we do is + + align:start position:0% +and what we do is + + + align:start position:0% +and what we do is +different um and that's our job that's + + align:start position:0% +different um and that's our job that's + + + align:start position:0% +different um and that's our job that's +what this is all about to try to get the + + align:start position:0% +what this is all about to try to get the + + + align:start position:0% +what this is all about to try to get the +head down to the body out to the hands + + align:start position:0% +head down to the body out to the hands + + + align:start position:0% +head down to the body out to the hands +and into this what it is we need and + + align:start position:0% +and into this what it is we need and + + + align:start position:0% +and into this what it is we need and +we're not going to get it right and I've + + align:start position:0% +we're not going to get it right and I've + + + align:start position:0% +we're not going to get it right and I've +been at it for a few years longer than + + align:start position:0% +been at it for a few years longer than + + + align:start position:0% +been at it for a few years longer than +you have and you'll see when I show you + + align:start position:0% +you have and you'll see when I show you + + + align:start position:0% +you have and you'll see when I show you +my own with I don't get it right either + + align:start position:0% +my own with I don't get it right either + + + align:start position:0% +my own with I don't get it right either +none of + + align:start position:0% +none of + + + align:start position:0% +none of +those I would like to challenge and + + align:start position:0% +those I would like to challenge and + + + align:start position:0% +those I would like to challenge and +question + + align:start position:0% +question + + + align:start position:0% +question +whether in this case the notion of this + + align:start position:0% +whether in this case the notion of this + + + align:start position:0% +whether in this case the notion of this +cover need to be as organic as what + + align:start position:0% +cover need to be as organic as what + + + align:start position:0% +cover need to be as organic as what +you're suggesting + + align:start position:0% +you're suggesting + + + align:start position:0% +you're suggesting +here + + align:start position:0% +here + + + align:start position:0% +here +because when I see if I if I when I saw + + align:start position:0% +because when I see if I if I when I saw + + + align:start position:0% +because when I see if I if I when I saw +this there is something already very + + align:start position:0% +this there is something already very + + + align:start position:0% +this there is something already very +elegant about the abstraction of this + + align:start position:0% +elegant about the abstraction of this + + + align:start position:0% +elegant about the abstraction of this +cover against the cord people see + + align:start position:0% +cover against the cord people see + + + align:start position:0% +cover against the cord people see +that um it's quite beautiful I was + + align:start position:0% +that um it's quite beautiful I was + + + align:start position:0% +that um it's quite beautiful I was +sitting over there looking at it and and + + align:start position:0% +sitting over there looking at it and and + + + align:start position:0% +sitting over there looking at it and and +the curved forms and the way that that + + align:start position:0% +the curved forms and the way that that + + + align:start position:0% +the curved forms and the way that that +you have started to address the solid is + + align:start position:0% +you have started to address the solid is + + + align:start position:0% +you have started to address the solid is +quite wonderful more wonderful in my + + align:start position:0% +quite wonderful more wonderful in my + + + align:start position:0% +quite wonderful more wonderful in my +mind than what's in your mind which is + + align:start position:0% +mind than what's in your mind which is + + + align:start position:0% +mind than what's in your mind which is +this and this is a takeoff I mean this + + align:start position:0% +this and this is a takeoff I mean this + + + align:start position:0% +this and this is a takeoff I mean this +is the beginning but whether would you + + align:start position:0% +is the beginning but whether would you + + + align:start position:0% +is the beginning but whether would you +correctly + + align:start position:0% +correctly + + + align:start position:0% +correctly +translate the architectural form and + + align:start position:0% +translate the architectural form and + + + align:start position:0% +translate the architectural form and +this great + + align:start position:0% +this great + + + align:start position:0% +this great +problem is not clear there could be + + align:start position:0% +problem is not clear there could be + + + align:start position:0% +problem is not clear there could be +another form as an example these could + + align:start position:0% +another form as an example these could + + + align:start position:0% +another form as an example these could +be even more uh + + align:start position:0% +be even more uh + + + align:start position:0% +be even more uh +Sals might move around flutter canvas + + align:start position:0% +Sals might move around flutter canvas + + + align:start position:0% +Sals might move around flutter canvas +different materials but it's very very + + align:start position:0% +different materials but it's very very + + + align:start position:0% +different materials but it's very very +powerful the form making of This related + + align:start position:0% +powerful the form making of This related + + + align:start position:0% +powerful the form making of This related +to the qualities of underneath I also + + align:start position:0% +to the qualities of underneath I also + + + align:start position:0% +to the qualities of underneath I also +think in this one is very exciting that + + align:start position:0% +think in this one is very exciting that + + + align:start position:0% +think in this one is very exciting that +she has made some changes on it add + + align:start position:0% +she has made some changes on it add + + + align:start position:0% +she has made some changes on it add +added to it but we've reinforced the + + align:start position:0% +added to it but we've reinforced the + + + align:start position:0% +added to it but we've reinforced the +place so you are what I would say very + + align:start position:0% +place so you are what I would say very + + + align:start position:0% +place so you are what I would say very +contexture you're taking what's there + + align:start position:0% +contexture you're taking what's there + + + align:start position:0% +contexture you're taking what's there +follow the Clue the C incred Prov good + + align:start position:0% +follow the Clue the C incred Prov good + + + align:start position:0% +follow the Clue the C incred Prov good +start but you're only halfway there in + + align:start position:0% +start but you're only halfway there in + + + align:start position:0% +start but you're only halfway there in +terms of the architectural form but + + align:start position:0% +terms of the architectural form but + + + align:start position:0% +terms of the architectural form but +you're a good halfway there in the sense + + align:start position:0% +you're a good halfway there in the sense + + + align:start position:0% +you're a good halfway there in the sense +that you're relating this to the nature + + align:start position:0% +that you're relating this to the nature + + + align:start position:0% +that you're relating this to the nature +to the C this to the sky I think this is + + align:start position:0% +to the C this to the sky I think this is + + + align:start position:0% +to the C this to the sky I think this is +horrible + + align:start position:0% +horrible + + + align:start position:0% +horrible +agree you know like the fire es skap + + align:start position:0% +agree you know like the fire es skap + + + align:start position:0% +agree you know like the fire es skap +coming down second means of eress which + + align:start position:0% +coming down second means of eress which + + + align:start position:0% +coming down second means of eress which +is not what + + align:start position:0% +is not what + + + align:start position:0% +is not what +AR um this is a little bit better but + + align:start position:0% +AR um this is a little bit better but + + + align:start position:0% +AR um this is a little bit better but +still could be a little bit more subtle + + align:start position:0% +still could be a little bit more subtle + + + align:start position:0% +still could be a little bit more subtle +uh I don't know where I'm talking you + + align:start position:0% +uh I don't know where I'm talking you + + + align:start position:0% +uh I don't know where I'm talking you +have me the other day here I don't want + + align:start position:0% +have me the other day here I don't want + + + align:start position:0% +have me the other day here I don't want +to be there thank you be some El so uh + + align:start position:0% +to be there thank you be some El so uh + + + align:start position:0% +to be there thank you be some El so uh +be careful about suggesting where the + + align:start position:0% +be careful about suggesting where the + + + align:start position:0% +be careful about suggesting where the +classroom is in terms of the + + align:start position:0% +classroom is in terms of the + + + align:start position:0% +classroom is in terms of the +direction because professors may not + + align:start position:0% +direction because professors may not + + + align:start position:0% +direction because professors may not +want to be where you want them to + + align:start position:0% +want to be where you want them to + + + align:start position:0% +want to be where you want them to +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +be so but good start \ No newline at end of file diff --git a/Wi4W4PTzdhI.txt b/Wi4W4PTzdhI.txt new file mode 100644 index 0000000000000000000000000000000000000000..a02398834cdfc06b85570dfb40c4827520d1de4d --- /dev/null +++ b/Wi4W4PTzdhI.txt @@ -0,0 +1,843 @@ +align:start position:0% + +welcome to the launch of our course on + + align:start position:0% +welcome to the launch of our course on + + + align:start position:0% +welcome to the launch of our course on +shaping the future of work together over + + align:start position:0% +shaping the future of work together over + + + align:start position:0% +shaping the future of work together over +the next seven weeks we'll explore how + + align:start position:0% +the next seven weeks we'll explore how + + + align:start position:0% +the next seven weeks we'll explore how +to expand the number of good jobs career + + align:start position:0% +to expand the number of good jobs career + + + align:start position:0% +to expand the number of good jobs career +opportunities and workplaces that help + + align:start position:0% +opportunities and workplaces that help + + + align:start position:0% +opportunities and workplaces that help +us all realize our dreams our + + align:start position:0% +us all realize our dreams our + + + align:start position:0% +us all realize our dreams our +aspirations we have for work for our + + align:start position:0% +aspirations we have for work for our + + + align:start position:0% +aspirations we have for work for our +family lives and for building + + align:start position:0% +family lives and for building + + + align:start position:0% +family lives and for building +sustainable successful Enterprises and + + align:start position:0% +sustainable successful Enterprises and + + + align:start position:0% +sustainable successful Enterprises and +for our + + align:start position:0% +for our + + + align:start position:0% +for our +societies but before we talk about that + + align:start position:0% +societies but before we talk about that + + + align:start position:0% +societies but before we talk about that +let's talk about some of the + + align:start position:0% +let's talk about some of the + + + align:start position:0% +let's talk about some of the +difficulties we've experienced in the + + align:start position:0% +difficulties we've experienced in the + + + align:start position:0% +difficulties we've experienced in the +last week or so I want to begin with a + + align:start position:0% +last week or so I want to begin with a + + + align:start position:0% +last week or so I want to begin with a +statement of solidary for our colleagues + + align:start position:0% +statement of solidary for our colleagues + + + align:start position:0% +statement of solidary for our colleagues +in Europe and in Asia in light light of + + align:start position:0% +in Europe and in Asia in light light of + + + align:start position:0% +in Europe and in Asia in light light of +the terrible tragedies that have + + align:start position:0% +the terrible tragedies that have + + + align:start position:0% +the terrible tragedies that have +occurred in Brussels and in Pakistan + + align:start position:0% +occurred in Brussels and in Pakistan + + + align:start position:0% +occurred in Brussels and in Pakistan +today we are all sharing our concern + + align:start position:0% +today we are all sharing our concern + + + align:start position:0% +today we are all sharing our concern +that there have been over the past 18 + + align:start position:0% +that there have been over the past 18 + + + align:start position:0% +that there have been over the past 18 +months 75 bombings in over 20 countries + + align:start position:0% +months 75 bombings in over 20 countries + + + align:start position:0% +months 75 bombings in over 20 countries +killing over 1300 people we think about + + align:start position:0% +killing over 1300 people we think about + + + align:start position:0% +killing over 1300 people we think about +the grief and the pain that so many + + align:start position:0% +the grief and the pain that so many + + + align:start position:0% +the grief and the pain that so many +nationalities and religions and people + + align:start position:0% +nationalities and religions and people + + + align:start position:0% +nationalities and religions and people +of different cultures all over the world + + align:start position:0% +of different cultures all over the world + + + align:start position:0% +of different cultures all over the world +have been experiencing and we are with + + align:start position:0% +have been experiencing and we are with + + + align:start position:0% +have been experiencing and we are with +them together my fellow cours team + + align:start position:0% +them together my fellow cours team + + + align:start position:0% +them together my fellow cours team +members here at MIT and I feel + + align:start position:0% +members here at MIT and I feel + + + align:start position:0% +members here at MIT and I feel +profoundly sad at yet more acts of + + align:start position:0% +profoundly sad at yet more acts of + + + align:start position:0% +profoundly sad at yet more acts of +violence we condemn them we we are + + align:start position:0% +violence we condemn them we we are + + + align:start position:0% +violence we condemn them we we are +committed to addressing the causes of + + align:start position:0% +committed to addressing the causes of + + + align:start position:0% +committed to addressing the causes of +violence in our societies and in our + + align:start position:0% +violence in our societies and in our + + + align:start position:0% +violence in our societies and in our +workplaces and to doing everything we + + align:start position:0% +workplaces and to doing everything we + + + align:start position:0% +workplaces and to doing everything we +can to help resolve these differences + + align:start position:0% +can to help resolve these differences + + + align:start position:0% +can to help resolve these differences +before they devolve into terrorism above + + align:start position:0% +before they devolve into terrorism above + + + align:start position:0% +before they devolve into terrorism above +all this course rests on the principle + + align:start position:0% +all this course rests on the principle + + + align:start position:0% +all this course rests on the principle +of respect for diversity in our world in + + align:start position:0% +of respect for diversity in our world in + + + align:start position:0% +of respect for diversity in our world in +our + + align:start position:0% +our + + + align:start position:0% +our +workplaces we had planned to show a bit + + align:start position:0% +workplaces we had planned to show a bit + + + align:start position:0% +workplaces we had planned to show a bit +later in the course a 20-minute video + + align:start position:0% +later in the course a 20-minute video + + + align:start position:0% +later in the course a 20-minute video +interview with Mary Row one of the + + align:start position:0% +interview with Mary Row one of the + + + align:start position:0% +interview with Mary Row one of the +world's leaders in managing diversity + + align:start position:0% +world's leaders in managing diversity + + + align:start position:0% +world's leaders in managing diversity +and workplace conflicts Mary outlines + + align:start position:0% +and workplace conflicts Mary outlines + + + align:start position:0% +and workplace conflicts Mary outlines +the ways that we can address these + + align:start position:0% +the ways that we can address these + + + align:start position:0% +the ways that we can address these +tensions and the anger that they de they + + align:start position:0% +tensions and the anger that they de they + + + align:start position:0% +tensions and the anger that they de they +show in our society and that sometimes + + align:start position:0% +show in our society and that sometimes + + + align:start position:0% +show in our society and that sometimes +do spill over to our places of work but + + align:start position:0% +do spill over to our places of work but + + + align:start position:0% +do spill over to our places of work but +given the events in Europe and Asia and + + align:start position:0% +given the events in Europe and Asia and + + + align:start position:0% +given the events in Europe and Asia and +other parts of the world we'll post that + + align:start position:0% +other parts of the world we'll post that + + + align:start position:0% +other parts of the world we'll post that +interview this week so we can start + + align:start position:0% +interview this week so we can start + + + align:start position:0% +interview this week so we can start +discussing these issues now so we invite + + align:start position:0% +discussing these issues now so we invite + + + align:start position:0% +discussing these issues now so we invite +you to watch Mary's interview and use it + + align:start position:0% +you to watch Mary's interview and use it + + + align:start position:0% +you to watch Mary's interview and use it +uh in the discussion forum to comment on + + align:start position:0% +uh in the discussion forum to comment on + + + align:start position:0% +uh in the discussion forum to comment on +how issues of diversity inclusion and + + align:start position:0% +how issues of diversity inclusion and + + + align:start position:0% +how issues of diversity inclusion and +the management of inequities can be + + align:start position:0% +the management of inequities can be + + + align:start position:0% +the management of inequities can be +addressed in your workplace and in your + + align:start position:0% +addressed in your workplace and in your + + + align:start position:0% +addressed in your workplace and in your +job experiences we can design a better + + align:start position:0% +job experiences we can design a better + + + align:start position:0% +job experiences we can design a better +future as we help each other shape this + + align:start position:0% +future as we help each other shape this + + + align:start position:0% +future as we help each other shape this +aspect of our workplaces in a positive + + align:start position:0% +aspect of our workplaces in a positive + + + align:start position:0% +aspect of our workplaces in a positive +way I invite you also to get started by + + align:start position:0% +way I invite you also to get started by + + + align:start position:0% +way I invite you also to get started by +sampling the rich a array of other + + align:start position:0% +sampling the rich a array of other + + + align:start position:0% +sampling the rich a array of other +videos that we have posted this week we + + align:start position:0% +videos that we have posted this week we + + + align:start position:0% +videos that we have posted this week we +have welcoming comments from National + + align:start position:0% +have welcoming comments from National + + + align:start position:0% +have welcoming comments from National +and internationally res renowned leaders + + align:start position:0% +and internationally res renowned leaders + + + align:start position:0% +and internationally res renowned leaders +from all over the world the US Secretary + + align:start position:0% +from all over the world the US Secretary + + + align:start position:0% +from all over the world the US Secretary +of Labor Tom Perez the director general + + align:start position:0% +of Labor Tom Perez the director general + + + align:start position:0% +of Labor Tom Perez the director general +of the international labor organization + + align:start position:0% +of the international labor organization + + + align:start position:0% +of the international labor organization +guy Ryder the secretary treasurer of + + align:start position:0% +guy Ryder the secretary treasurer of + + + align:start position:0% +guy Ryder the secretary treasurer of +America's largest Union Federation Liz + + align:start position:0% +America's largest Union Federation Liz + + + align:start position:0% +America's largest Union Federation Liz +Schuler and our course teams Human + + align:start position:0% +Schuler and our course teams Human + + + align:start position:0% +Schuler and our course teams Human +Resource Management expert Lee Dyer we + + align:start position:0% +Resource Management expert Lee Dyer we + + + align:start position:0% +Resource Management expert Lee Dyer we +include this diversity of voices to show + + align:start position:0% +include this diversity of voices to show + + + align:start position:0% +include this diversity of voices to show +how all of these communities need to + + align:start position:0% +how all of these communities need to + + + align:start position:0% +how all of these communities need to +work together to shape the future of + + align:start position:0% +work together to shape the future of + + + align:start position:0% +work together to shape the future of +work for you and for all the parties + + align:start position:0% +work for you and for all the parties + + + align:start position:0% +work for you and for all the parties +that have a stake in it and don't miss + + align:start position:0% +that have a stake in it and don't miss + + + align:start position:0% +that have a stake in it and don't miss +our three minute animated video + + align:start position:0% +our three minute animated video + + + align:start position:0% +our three minute animated video +summarizing 3,000 years of the history + + align:start position:0% +summarizing 3,000 years of the history + + + align:start position:0% +summarizing 3,000 years of the history +of work I think you will enjoy it then + + align:start position:0% +of work I think you will enjoy it then + + + align:start position:0% +of work I think you will enjoy it then +we move on to other videos and readings + + align:start position:0% +we move on to other videos and readings + + + align:start position:0% +we move on to other videos and readings +that discuss the challenges and exciting + + align:start position:0% +that discuss the challenges and exciting + + + align:start position:0% +that discuss the challenges and exciting +opportunities Innovations occurring in + + align:start position:0% +opportunities Innovations occurring in + + + align:start position:0% +opportunities Innovations occurring in +our workplaces today these set the stage + + align:start position:0% +our workplaces today these set the stage + + + align:start position:0% +our workplaces today these set the stage +for a much much more in-depth + + align:start position:0% +for a much much more in-depth + + + align:start position:0% +for a much much more in-depth +conversation about these issues in the + + align:start position:0% +conversation about these issues in the + + + align:start position:0% +conversation about these issues in the +weeks + + align:start position:0% +weeks + + + align:start position:0% +weeks +ahead we also uh note in your discussion + + align:start position:0% +ahead we also uh note in your discussion + + + align:start position:0% +ahead we also uh note in your discussion +form that you already started that some + + align:start position:0% +form that you already started that some + + + align:start position:0% +form that you already started that some +of you are concerned about how the + + align:start position:0% +of you are concerned about how the + + + align:start position:0% +of you are concerned about how the +issues of jobs and the future of work + + align:start position:0% +issues of jobs and the future of work + + + align:start position:0% +issues of jobs and the future of work +are being discussed in the presidential + + align:start position:0% +are being discussed in the presidential + + + align:start position:0% +are being discussed in the presidential +campaign in the United States some of + + align:start position:0% +campaign in the United States some of + + + align:start position:0% +campaign in the United States some of +you have lamented that yes they talk + + align:start position:0% +you have lamented that yes they talk + + + align:start position:0% +you have lamented that yes they talk +about jobs but don't have a vision for + + align:start position:0% +about jobs but don't have a vision for + + + align:start position:0% +about jobs but don't have a vision for +the future of work well maybe it's our + + align:start position:0% +the future of work well maybe it's our + + + align:start position:0% +the future of work well maybe it's our +job to bring our voices into these + + align:start position:0% +job to bring our voices into these + + + align:start position:0% +job to bring our voices into these +conversations as we will try to do and + + align:start position:0% +conversations as we will try to do and + + + align:start position:0% +conversations as we will try to do and +really lay out a vision for what work + + align:start position:0% +really lay out a vision for what work + + + align:start position:0% +really lay out a vision for what work +could be what the real needs of workers + + align:start position:0% +could be what the real needs of workers + + + align:start position:0% +could be what the real needs of workers +are what the real needs of businesses + + align:start position:0% +are what the real needs of businesses + + + align:start position:0% +are what the real needs of businesses +are today so maybe we can add our voices + + align:start position:0% +are today so maybe we can add our voices + + + align:start position:0% +are today so maybe we can add our voices +to this discussion so welcome join us + + align:start position:0% +to this discussion so welcome join us + + + align:start position:0% +to this discussion so welcome join us +look forward to having you uh engage + + align:start position:0% +look forward to having you uh engage + + + align:start position:0% +look forward to having you uh engage +with us and helping to see if we can use + + align:start position:0% +with us and helping to see if we can use + + + align:start position:0% +with us and helping to see if we can use +our Collective efforts to shape the + + align:start position:0% +our Collective efforts to shape the + + + align:start position:0% +our Collective efforts to shape the +future of work \ No newline at end of file diff --git a/WiFahA1iAv4.txt b/WiFahA1iAv4.txt new file mode 100644 index 0000000000000000000000000000000000000000..69a4a98d8eb08099cd6a84afd009ebfc8f9a31e0 --- /dev/null +++ b/WiFahA1iAv4.txt @@ -0,0 +1,10459 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT open courseware continue + + align:start position:0% +will help MIT open courseware continue + + + align:start position:0% +will help MIT open courseware continue +to offer highquality educational + + align:start position:0% +to offer highquality educational + + + align:start position:0% +to offer highquality educational +resources for free to make a donation or + + align:start position:0% +resources for free to make a donation or + + + align:start position:0% +resources for free to make a donation or +view additional materials from hundreds + + align:start position:0% +view additional materials from hundreds + + + align:start position:0% +view additional materials from hundreds +of MIT courses visit mitop courseware at + + align:start position:0% + + + + align:start position:0% + +ocw.mit.edu all right um and I really + + align:start position:0% +ocw.mit.edu all right um and I really + + + align:start position:0% +ocw.mit.edu all right um and I really +wanted to show you my little Hook video + + align:start position:0% +wanted to show you my little Hook video + + + align:start position:0% +wanted to show you my little Hook video +and I downloaded it so I thought we'd + + align:start position:0% +and I downloaded it so I thought we'd + + + align:start position:0% +and I downloaded it so I thought we'd +start just by watching that and then + + align:start position:0% +start just by watching that and then + + + align:start position:0% +start just by watching that and then +I'll pick up um about modeling Foams + + align:start position:0% +I'll pick up um about modeling Foams + + + align:start position:0% +I'll pick up um about modeling Foams +okay so this takes like nine or 10 + + align:start position:0% +okay so this takes like nine or 10 + + + align:start position:0% +okay so this takes like nine or 10 +minutes but um I just thought it was + + align:start position:0% +minutes but um I just thought it was + + + align:start position:0% +minutes but um I just thought it was +cute and I made it and I want you to see + + align:start position:0% +cute and I made it and I want you to see + + + align:start position:0% +cute and I made it and I want you to see +it so so let's do that to + + align:start position:0% +it so so let's do that to + + + align:start position:0% +it so so let's do that to +start we're here at the har University + + align:start position:0% +start we're here at the har University + + + align:start position:0% +start we're here at the har University +boty Library looking at a first edition + + align:start position:0% +boty Library looking at a first edition + + + align:start position:0% +boty Library looking at a first edition +of Robert Ho's micrographia published + + align:start position:0% +of Robert Ho's micrographia published + + + align:start position:0% +of Robert Ho's micrographia published +how do I get rid of the bar Craig oh + + align:start position:0% +how do I get rid of the bar Craig oh + + + align:start position:0% +how do I get rid of the bar Craig oh +there book to show the microscopic + + align:start position:0% +there book to show the microscopic + + + align:start position:0% +there book to show the microscopic +structure of materials and it has a + + align:start position:0% +structure of materials and it has a + + + align:start position:0% +structure of materials and it has a +number of remarkable drawings in it here + + align:start position:0% +number of remarkable drawings in it here + + + align:start position:0% +number of remarkable drawings in it here +we see drawings of silk these are two + + align:start position:0% +we see drawings of silk these are two + + + align:start position:0% +we see drawings of silk these are two +different silks on the top here we have + + align:start position:0% +different silks on the top here we have + + + align:start position:0% +different silks on the top here we have +a fine whed silk and in this more + + align:start position:0% +a fine whed silk and in this more + + + align:start position:0% +a fine whed silk and in this more +detailed drawing down here you can see + + align:start position:0% +detailed drawing down here you can see + + + align:start position:0% +detailed drawing down here you can see +the pattern of the weaving of the silk + + align:start position:0% +the pattern of the weaving of the silk + + + align:start position:0% +the pattern of the weaving of the silk +the bottom image here is a drawing of + + align:start position:0% +the bottom image here is a drawing of + + + align:start position:0% +the bottom image here is a drawing of +watered silk and over here there's + + align:start position:0% +watered silk and over here there's + + + align:start position:0% +watered silk and over here there's +another higher magnification image and + + align:start position:0% +another higher magnification image and + + + align:start position:0% +another higher magnification image and +you can see the pattern here is more + + align:start position:0% +you can see the pattern here is more + + + align:start position:0% +you can see the pattern here is more +sharply angled and it appears that this + + align:start position:0% +sharply angled and it appears that this + + + align:start position:0% +sharply angled and it appears that this +sharper angle here gives the different + + align:start position:0% +sharper angle here gives the different + + + align:start position:0% +sharper angle here gives the different +texture to the surface finish of the + + align:start position:0% +texture to the surface finish of the + + + align:start position:0% +texture to the surface finish of the +silk so here we see a drawing of charred + + align:start position:0% +silk so here we see a drawing of charred + + + align:start position:0% +silk so here we see a drawing of charred +wood and one of the things I find + + align:start position:0% +wood and one of the things I find + + + align:start position:0% +wood and one of the things I find +interesting about this drawing is how + + align:start position:0% +interesting about this drawing is how + + + align:start position:0% +interesting about this drawing is how +similar it is to Modern electron micr + + align:start position:0% +similar it is to Modern electron micr + + + align:start position:0% +similar it is to Modern electron micr +you see and in this drawing we can see + + align:start position:0% +you see and in this drawing we can see + + + align:start position:0% +you see and in this drawing we can see +two of the main features we see these + + align:start position:0% +two of the main features we see these + + + align:start position:0% +two of the main features we see these +small cells which are fibers that + + align:start position:0% +small cells which are fibers that + + + align:start position:0% +small cells which are fibers that +provide structural support to the tree + + align:start position:0% +provide structural support to the tree + + + align:start position:0% +provide structural support to the tree +and we see these larger cells here which + + align:start position:0% +and we see these larger cells here which + + + align:start position:0% +and we see these larger cells here which +are vessels which allow fluids to go up + + align:start position:0% +are vessels which allow fluids to go up + + + align:start position:0% +are vessels which allow fluids to go up +and down the tree and here we see a + + align:start position:0% +and down the tree and here we see a + + + align:start position:0% +and down the tree and here we see a +drawing of the surface of a rosemary + + align:start position:0% +drawing of the surface of a rosemary + + + align:start position:0% +drawing of the surface of a rosemary +leaf with an unexpected tiny little bars + + align:start position:0% +leaf with an unexpected tiny little bars + + + align:start position:0% +leaf with an unexpected tiny little bars +and this is something that you can only + + align:start position:0% +and this is something that you can only + + + align:start position:0% +and this is something that you can only +see with a microscope you wouldn't + + align:start position:0% +see with a microscope you wouldn't + + + align:start position:0% +see with a microscope you wouldn't +expect to see those if you just feel the + + align:start position:0% +expect to see those if you just feel the + + + align:start position:0% +expect to see those if you just feel the +surface of the Rosary so it's kind of + + align:start position:0% +surface of the Rosary so it's kind of + + + align:start position:0% +surface of the Rosary so it's kind of +interesting that with the microscope you + + align:start position:0% +interesting that with the microscope you + + + align:start position:0% +interesting that with the microscope you +can see these features that are + + align:start position:0% +can see these features that are + + + align:start position:0% +can see these features that are +invisible to the naked + + align:start position:0% +invisible to the naked + + + align:start position:0% +invisible to the naked +ey one of the main themes of Material + + align:start position:0% +ey one of the main themes of Material + + + align:start position:0% +ey one of the main themes of Material +Science is that the properties of + + align:start position:0% +Science is that the properties of + + + align:start position:0% +Science is that the properties of +materials are related to their structure + + align:start position:0% +materials are related to their structure + + + align:start position:0% +materials are related to their structure +and so being able to see the structure + + align:start position:0% +and so being able to see the structure + + + align:start position:0% +and so being able to see the structure +at a microscopic scale is very helpful + + align:start position:0% +at a microscopic scale is very helpful + + + align:start position:0% +at a microscopic scale is very helpful +and today we can even see the structure + + align:start position:0% +and today we can even see the structure + + + align:start position:0% +and today we can even see the structure +at the atomic scale Robert Hook + + align:start position:0% +at the atomic scale Robert Hook + + + align:start position:0% +at the atomic scale Robert Hook +understood this idea + + align:start position:0% +understood this idea + + + align:start position:0% +understood this idea +and in the description of the cork hook + + align:start position:0% +and in the description of the cork hook + + + align:start position:0% +and in the description of the cork hook +States I no sooner discerned these which + + align:start position:0% +States I no sooner discerned these which + + + align:start position:0% +States I no sooner discerned these which +were the first microscopical pores I + + align:start position:0% +were the first microscopical pores I + + + align:start position:0% +were the first microscopical pores I +ever saw but me thought that I had with + + align:start position:0% +ever saw but me thought that I had with + + + align:start position:0% +ever saw but me thought that I had with +the discovery of them perfectly hinted + + align:start position:0% +the discovery of them perfectly hinted + + + align:start position:0% +the discovery of them perfectly hinted +to me the true and intelligible reason + + align:start position:0% +to me the true and intelligible reason + + + align:start position:0% +to me the true and intelligible reason +for all of the phenomena of cork so what + + align:start position:0% +for all of the phenomena of cork so what + + + align:start position:0% +for all of the phenomena of cork so what +he's saying here is that by looking at + + align:start position:0% +he's saying here is that by looking at + + + align:start position:0% +he's saying here is that by looking at +the structure and looking at these cells + + align:start position:0% +the structure and looking at these cells + + + align:start position:0% +the structure and looking at these cells +here in the drawing he thinks he can + + align:start position:0% +here in the drawing he thinks he can + + + align:start position:0% +here in the drawing he thinks he can +understand the properties of cork or the + + align:start position:0% +understand the properties of cork or the + + + align:start position:0% +understand the properties of cork or the +phenomena of cork what was it about + + align:start position:0% +phenomena of cork what was it about + + + align:start position:0% +phenomena of cork what was it about +Robert Hook that allowed him to make + + align:start position:0% +Robert Hook that allowed him to make + + + align:start position:0% +Robert Hook that allowed him to make +this book why was it him and not + + align:start position:0% +this book why was it him and not + + + align:start position:0% +this book why was it him and not +somebody else well Robert Hook had kind + + align:start position:0% +somebody else well Robert Hook had kind + + + align:start position:0% +somebody else well Robert Hook had kind +of an interesting history he grew up on + + align:start position:0% +of an interesting history he grew up on + + + align:start position:0% +of an interesting history he grew up on +the aisle of white and as a boy he loved + + align:start position:0% +the aisle of white and as a boy he loved + + + align:start position:0% +the aisle of white and as a boy he loved +making drawings and he got quite skilled + + align:start position:0% +making drawings and he got quite skilled + + + align:start position:0% +making drawings and he got quite skilled +at making drawings the other thing was + + align:start position:0% +at making drawings the other thing was + + + align:start position:0% +at making drawings the other thing was +he loved making models of things he made + + align:start position:0% +he loved making models of things he made + + + align:start position:0% +he loved making models of things he made +models of ships he made a a wooden clock + + align:start position:0% +models of ships he made a a wooden clock + + + align:start position:0% +models of ships he made a a wooden clock +that was a working clock when he was a + + align:start position:0% +that was a working clock when he was a + + + align:start position:0% +that was a working clock when he was a +kid and as a teenager he moved to London + + align:start position:0% +kid and as a teenager he moved to London + + + align:start position:0% +kid and as a teenager he moved to London +and he became an apprentice to Sir Peter + + align:start position:0% +and he became an apprentice to Sir Peter + + + align:start position:0% +and he became an apprentice to Sir Peter +Lily who was a famous painter of the + + align:start position:0% +Lily who was a famous painter of the + + + align:start position:0% +Lily who was a famous painter of the +time so his drawing was good enough that + + align:start position:0% +time so his drawing was good enough that + + + align:start position:0% +time so his drawing was good enough that +he would be working with a very + + align:start position:0% +he would be working with a very + + + align:start position:0% +he would be working with a very +well-known painter after he did that he + + align:start position:0% +well-known painter after he did that he + + + align:start position:0% +well-known painter after he did that he +went to the Westminister school and he + + align:start position:0% +went to the Westminister school and he + + + align:start position:0% +went to the Westminister school and he +studied Classics he studied mathematics + + align:start position:0% +studied Classics he studied mathematics + + + align:start position:0% +studied Classics he studied mathematics +but he also learned to use a lathe and + + align:start position:0% +but he also learned to use a lathe and + + + align:start position:0% +but he also learned to use a lathe and +this was also very helpful in him making + + align:start position:0% +this was also very helpful in him making + + + align:start position:0% +this was also very helpful in him making +various sorts of + + align:start position:0% +various sorts of + + + align:start position:0% +various sorts of +apparatus and as a student at Oxford he + + align:start position:0% +apparatus and as a student at Oxford he + + + align:start position:0% +apparatus and as a student at Oxford he +worked in the lab of Robert Bole and his + + align:start position:0% +worked in the lab of Robert Bole and his + + + align:start position:0% +worked in the lab of Robert Bole and his +job in that lab was to develop + + align:start position:0% +job in that lab was to develop + + + align:start position:0% +job in that lab was to develop +scientific apparatus and he did things + + align:start position:0% +scientific apparatus and he did things + + + align:start position:0% +scientific apparatus and he did things +like he built pumps that allowed Robert + + align:start position:0% +like he built pumps that allowed Robert + + + align:start position:0% +like he built pumps that allowed Robert +Bole to do the experiments that led to + + align:start position:0% +Bole to do the experiments that led to + + + align:start position:0% +Bole to do the experiments that led to +Bo + + align:start position:0% +Bo + + + align:start position:0% +Bo +law when he returned to London after + + align:start position:0% +law when he returned to London after + + + align:start position:0% +law when he returned to London after +Oxford he became the curator of + + align:start position:0% +Oxford he became the curator of + + + align:start position:0% +Oxford he became the curator of +experiments at the Royal Society and one + + align:start position:0% +experiments at the Royal Society and one + + + align:start position:0% +experiments at the Royal Society and one +of the things he did was he got a + + align:start position:0% +of the things he did was he got a + + + align:start position:0% +of the things he did was he got a +microscope he improved that microscope + + align:start position:0% +microscope he improved that microscope + + + align:start position:0% +microscope he improved that microscope +increasing their magnification which was + + align:start position:0% +increasing their magnification which was + + + align:start position:0% +increasing their magnification which was +what allowed him to make the beautiful + + align:start position:0% +what allowed him to make the beautiful + + + align:start position:0% +what allowed him to make the beautiful +drawings that we see today and here in + + align:start position:0% +drawings that we see today and here in + + + align:start position:0% +drawings that we see today and here in +the preface of the book we see that he + + align:start position:0% +the preface of the book we see that he + + + align:start position:0% +the preface of the book we see that he +even made a drawing of his microscope so + + align:start position:0% +even made a drawing of his microscope so + + + align:start position:0% +even made a drawing of his microscope so +this thing down here this is Robert + + align:start position:0% +this thing down here this is Robert + + + align:start position:0% +this thing down here this is Robert +Hook's + + align:start position:0% +Hook's + + + align:start position:0% +Hook's +microscope the development of new + + align:start position:0% +microscope the development of new + + + align:start position:0% +microscope the development of new +microscopes with higher and higher + + align:start position:0% +microscopes with higher and higher + + + align:start position:0% +microscopes with higher and higher +magnifications continues to this day + + align:start position:0% +magnifications continues to this day + + + align:start position:0% +magnifications continues to this day +scanning electron microscopes were + + align:start position:0% +scanning electron microscopes were + + + align:start position:0% +scanning electron microscopes were +invented in the 1960s and today we have + + align:start position:0% +invented in the 1960s and today we have + + + align:start position:0% +invented in the 1960s and today we have +transmission electron microscopes and + + align:start position:0% +transmission electron microscopes and + + + align:start position:0% +transmission electron microscopes and +atomic Force microscopes with even + + align:start position:0% +atomic Force microscopes with even + + + align:start position:0% +atomic Force microscopes with even +higher magnifications at these higher + + align:start position:0% +higher magnifications at these higher + + + align:start position:0% +higher magnifications at these higher +magnifications we can see details that + + align:start position:0% +magnifications we can see details that + + + align:start position:0% +magnifications we can see details that +hook was unable to see because of the + + align:start position:0% +hook was unable to see because of the + + + align:start position:0% +hook was unable to see because of the +limitations of the microscope that he + + align:start position:0% +limitations of the microscope that he + + + align:start position:0% +limitations of the microscope that he +had the optical microscope but it's + + align:start position:0% +had the optical microscope but it's + + + align:start position:0% +had the optical microscope but it's +interesting to see today the images we + + align:start position:0% +interesting to see today the images we + + + align:start position:0% +interesting to see today the images we +see in a scanning electron microscope at + + align:start position:0% +see in a scanning electron microscope at + + + align:start position:0% +see in a scanning electron microscope at +a similar magnification to those that + + align:start position:0% +a similar magnification to those that + + + align:start position:0% +a similar magnification to those that +hook saw in his optical microscope and + + align:start position:0% +hook saw in his optical microscope and + + + align:start position:0% +hook saw in his optical microscope and +it's it's remarkable to see how many of + + align:start position:0% +it's it's remarkable to see how many of + + + align:start position:0% +it's it's remarkable to see how many of +the features that we see in these much + + align:start position:0% +the features that we see in these much + + + align:start position:0% +the features that we see in these much +more fancy microscopes that he was able + + align:start position:0% +more fancy microscopes that he was able + + + align:start position:0% +more fancy microscopes that he was able +to capture in his drawings with his + + align:start position:0% +to capture in his drawings with his + + + align:start position:0% +to capture in his drawings with his +simple Optical microscope okay so here + + align:start position:0% +simple Optical microscope okay so here + + + align:start position:0% +simple Optical microscope okay so here +we have a picture of cork we have hooks + + align:start position:0% +we have a picture of cork we have hooks + + + align:start position:0% +we have a picture of cork we have hooks +drawings showing two perpendicular + + align:start position:0% +drawings showing two perpendicular + + + align:start position:0% +drawings showing two perpendicular +planes we also have this nice little + + align:start position:0% +planes we also have this nice little + + + align:start position:0% +planes we also have this nice little +drawing of a cork Branch here cork is + + align:start position:0% +drawing of a cork Branch here cork is + + + align:start position:0% +drawing of a cork Branch here cork is +the Bark from the cork oak tree and in + + align:start position:0% +the Bark from the cork oak tree and in + + + align:start position:0% +the Bark from the cork oak tree and in +Hook's drawings of the micro structure + + align:start position:0% +Hook's drawings of the micro structure + + + align:start position:0% +Hook's drawings of the micro structure +we can see these cells here are roughly + + align:start position:0% +we can see these cells here are roughly + + + align:start position:0% +we can see these cells here are roughly +boxlike they're more or less rectangular + + align:start position:0% +boxlike they're more or less rectangular + + + align:start position:0% +boxlike they're more or less rectangular +and these cells look more or less + + align:start position:0% +and these cells look more or less + + + align:start position:0% +and these cells look more or less +circular so there's these two different + + align:start position:0% +circular so there's these two different + + + align:start position:0% +circular so there's these two different +perpendicular planes in the Cork and + + align:start position:0% +perpendicular planes in the Cork and + + + align:start position:0% +perpendicular planes in the Cork and +when we look at these scanning electron + + align:start position:0% +when we look at these scanning electron + + + align:start position:0% +when we look at these scanning electron +micrographs we can see a very similar + + align:start position:0% +micrographs we can see a very similar + + + align:start position:0% +micrographs we can see a very similar +structure there's some cells that are + + align:start position:0% +structure there's some cells that are + + + align:start position:0% +structure there's some cells that are +roughly box-like and others that are + + align:start position:0% +roughly box-like and others that are + + + align:start position:0% +roughly box-like and others that are +more or less hexagonal or roughly + + align:start position:0% +more or less hexagonal or roughly + + + align:start position:0% +more or less hexagonal or roughly +rounded one feature that hook was not + + align:start position:0% +rounded one feature that hook was not + + + align:start position:0% +rounded one feature that hook was not +able to see though that you do see on + + align:start position:0% +able to see though that you do see on + + + align:start position:0% +able to see though that you do see on +the scanning electron micrographs is the + + align:start position:0% +the scanning electron micrographs is the + + + align:start position:0% +the scanning electron micrographs is the +waviness in the cell walls and that was + + align:start position:0% +waviness in the cell walls and that was + + + align:start position:0% +waviness in the cell walls and that was +because the resolution of his microscope + + align:start position:0% +because the resolution of his microscope + + + align:start position:0% +because the resolution of his microscope +was insufficient to see that level of + + align:start position:0% +was insufficient to see that level of + + + align:start position:0% +was insufficient to see that level of +detail and here in this illustration on + + align:start position:0% +detail and here in this illustration on + + + align:start position:0% +detail and here in this illustration on +the bottom here is a drawing of sponge + + align:start position:0% +the bottom here is a drawing of sponge + + + align:start position:0% +the bottom here is a drawing of sponge +and when we look at the scanning + + align:start position:0% +and when we look at the scanning + + + align:start position:0% +and when we look at the scanning +electron micrograph we see that the + + align:start position:0% +electron micrograph we see that the + + + align:start position:0% +electron micrograph we see that the +structure is remarkably similar to what + + align:start position:0% +structure is remarkably similar to what + + + align:start position:0% +structure is remarkably similar to what +Hook is drawn so here we have Hook's + + align:start position:0% +Hook is drawn so here we have Hook's + + + align:start position:0% +Hook is drawn so here we have Hook's +drawing of feathers and we can see he's + + align:start position:0% +drawing of feathers and we can see he's + + + align:start position:0% +drawing of feathers and we can see he's +made several drawings at different + + align:start position:0% +made several drawings at different + + + align:start position:0% +made several drawings at different +length scales and if we look at this one + + align:start position:0% +length scales and if we look at this one + + + align:start position:0% +length scales and if we look at this one +here we see the barbule and you can see + + align:start position:0% +here we see the barbule and you can see + + + align:start position:0% +here we see the barbule and you can see +this little hooked regions there and + + align:start position:0% +this little hooked regions there and + + + align:start position:0% +this little hooked regions there and +those hooks lock into the little + + align:start position:0% +those hooks lock into the little + + + align:start position:0% +those hooks lock into the little +feathers over on this side over here of + + align:start position:0% +feathers over on this side over here of + + + align:start position:0% +feathers over on this side over here of +the adjacent barbule and in the higher + + align:start position:0% +the adjacent barbule and in the higher + + + align:start position:0% +the adjacent barbule and in the higher +magnification picture you can see on one + + align:start position:0% +magnification picture you can see on one + + + align:start position:0% +magnification picture you can see on one +barbule there's hooks on one side but + + align:start position:0% +barbule there's hooks on one side but + + + align:start position:0% +barbule there's hooks on one side but +not on the other and it's this hooking + + align:start position:0% +not on the other and it's this hooking + + + align:start position:0% +not on the other and it's this hooking +of the two sections together that allows + + align:start position:0% +of the two sections together that allows + + + align:start position:0% +of the two sections together that allows +the feathers to maintain a smooth + + align:start position:0% +the feathers to maintain a smooth + + + align:start position:0% +the feathers to maintain a smooth +surface for the wing when the bird is + + align:start position:0% +surface for the wing when the bird is + + + align:start position:0% +surface for the wing when the bird is +flying and you can see the same sort of + + align:start position:0% +flying and you can see the same sort of + + + align:start position:0% +flying and you can see the same sort of +thing when you look at the electron + + align:start position:0% +thing when you look at the electron + + + align:start position:0% +thing when you look at the electron +micrographs you can see the little hooks + + align:start position:0% +micrographs you can see the little hooks + + + align:start position:0% +micrographs you can see the little hooks +on one side of the barbules and you can + + align:start position:0% +on one side of the barbules and you can + + + align:start position:0% +on one side of the barbules and you can +see how they interconnect together with + + align:start position:0% +see how they interconnect together with + + + align:start position:0% +see how they interconnect together with +the next Barb one of the most reproduced + + align:start position:0% +the next Barb one of the most reproduced + + + align:start position:0% +the next Barb one of the most reproduced +images from Hook's book is that of the + + align:start position:0% +images from Hook's book is that of the + + + align:start position:0% +images from Hook's book is that of the +flea this image we see here and you can + + align:start position:0% +flea this image we see here and you can + + + align:start position:0% +flea this image we see here and you can +see why it's a gorgeous image and it + + align:start position:0% +see why it's a gorgeous image and it + + + align:start position:0% +see why it's a gorgeous image and it +shows details that people had never seen + + align:start position:0% +shows details that people had never seen + + + align:start position:0% +shows details that people had never seen +before people were amazed to see that + + align:start position:0% +before people were amazed to see that + + + align:start position:0% +before people were amazed to see that +the little flea that they might have + + align:start position:0% +the little flea that they might have + + + align:start position:0% +the little flea that they might have +found on their dog or something was + + align:start position:0% +found on their dog or something was + + + align:start position:0% +found on their dog or something was +actually made up of this you know + + align:start position:0% +actually made up of this you know + + + align:start position:0% +actually made up of this you know +compound body with all these little + + align:start position:0% +compound body with all these little + + + align:start position:0% +compound body with all these little +plates and little hairs here and you can + + align:start position:0% +plates and little hairs here and you can + + + align:start position:0% +plates and little hairs here and you can +see there little tiny claws on the legs + + align:start position:0% +see there little tiny claws on the legs + + + align:start position:0% +see there little tiny claws on the legs +and the legs have all these hairs nobody + + align:start position:0% +and the legs have all these hairs nobody + + + align:start position:0% +and the legs have all these hairs nobody +had any idea that this is what a flea + + align:start position:0% +had any idea that this is what a flea + + + align:start position:0% +had any idea that this is what a flea +actually looked like and so it it was an + + align:start position:0% +actually looked like and so it it was an + + + align:start position:0% +actually looked like and so it it was an +amazing drawing and it was something + + align:start position:0% +amazing drawing and it was something + + + align:start position:0% +amazing drawing and it was something +that people were just stunned by when + + align:start position:0% +that people were just stunned by when + + + align:start position:0% +that people were just stunned by when +when Hook's book came out and if we look + + align:start position:0% +when Hook's book came out and if we look + + + align:start position:0% +when Hook's book came out and if we look +at a modern electron micrograph we can + + align:start position:0% +at a modern electron micrograph we can + + + align:start position:0% +at a modern electron micrograph we can +see it's remarkably similar if we look + + align:start position:0% +see it's remarkably similar if we look + + + align:start position:0% +see it's remarkably similar if we look +at the same magnification so hook showed + + align:start position:0% +at the same magnification so hook showed + + + align:start position:0% +at the same magnification so hook showed +many of the same details showed some of + + align:start position:0% +many of the same details showed some of + + + align:start position:0% +many of the same details showed some of +the same hairs on the legs showed the + + align:start position:0% +the same hairs on the legs showed the + + + align:start position:0% +the same hairs on the legs showed the +same sorts of plates showed the claws at + + align:start position:0% +same sorts of plates showed the claws at + + + align:start position:0% +same sorts of plates showed the claws at +the ends of the legs and our modern + + align:start position:0% +the ends of the legs and our modern + + + align:start position:0% +the ends of the legs and our modern +image is probably from a different + + align:start position:0% +image is probably from a different + + + align:start position:0% +image is probably from a different +species of flea we don't know what + + align:start position:0% +species of flea we don't know what + + + align:start position:0% +species of flea we don't know what +species of flea that hook actually + + align:start position:0% +species of flea that hook actually + + + align:start position:0% +species of flea that hook actually +looked at but you can see there's a + + align:start position:0% +looked at but you can see there's a + + + align:start position:0% +looked at but you can see there's a +tremendous similarity between the two + + align:start position:0% +tremendous similarity between the two + + + align:start position:0% +tremendous similarity between the two +images and it's remarkable how many of + + align:start position:0% +images and it's remarkable how many of + + + align:start position:0% +images and it's remarkable how many of +the features that hook was able to + + align:start position:0% +the features that hook was able to + + + align:start position:0% +the features that hook was able to +capture in his drawing and here we have + + align:start position:0% +capture in his drawing and here we have + + + align:start position:0% +capture in his drawing and here we have +the compound eye of the fly and this + + align:start position:0% +the compound eye of the fly and this + + + align:start position:0% +the compound eye of the fly and this +again was astonishing to people in + + align:start position:0% +again was astonishing to people in + + + align:start position:0% +again was astonishing to people in +Hook's day and even today people look at + + align:start position:0% +Hook's day and even today people look at + + + align:start position:0% +Hook's day and even today people look at +this image and they're they're pretty + + align:start position:0% +this image and they're they're pretty + + + align:start position:0% +this image and they're they're pretty +amazed at the detail in this drawing and + + align:start position:0% +amazed at the detail in this drawing and + + + align:start position:0% +amazed at the detail in this drawing and +again we can compare this with a modern + + align:start position:0% +again we can compare this with a modern + + + align:start position:0% +again we can compare this with a modern +electron micrograph and again you can + + align:start position:0% +electron micrograph and again you can + + + align:start position:0% +electron micrograph and again you can +see the similarities between what hook + + align:start position:0% +see the similarities between what hook + + + align:start position:0% +see the similarities between what hook +saw and what we see in a modern scanning + + align:start position:0% +saw and what we see in a modern scanning + + + align:start position:0% +saw and what we see in a modern scanning +electron microscope at a similar + + align:start position:0% +electron microscope at a similar + + + align:start position:0% +electron microscope at a similar +magnification in the 1980s Atomic Force + + align:start position:0% +magnification in the 1980s Atomic Force + + + align:start position:0% +magnification in the 1980s Atomic Force +microscopes were invented which have a + + align:start position:0% +microscopes were invented which have a + + + align:start position:0% +microscopes were invented which have a +resolution down to tens of nanometers + + align:start position:0% +resolution down to tens of nanometers + + + align:start position:0% +resolution down to tens of nanometers +and today there's transmission electron + + align:start position:0% +and today there's transmission electron + + + align:start position:0% +and today there's transmission electron +microscopes which allow you to see the + + align:start position:0% +microscopes which allow you to see the + + + align:start position:0% +microscopes which allow you to see the +atomic structure so for instance in a + + align:start position:0% +atomic structure so for instance in a + + + align:start position:0% +atomic structure so for instance in a +crystal lattice you can see the + + align:start position:0% +crystal lattice you can see the + + + align:start position:0% +crystal lattice you can see the +individual atoms and the and the regular + + align:start position:0% +individual atoms and the and the regular + + + align:start position:0% +individual atoms and the and the regular +crystal + + align:start position:0% +crystal + + + align:start position:0% +crystal +structure today most experimental + + align:start position:0% +structure today most experimental + + + align:start position:0% +structure today most experimental +studies of materials include photographs + + align:start position:0% +studies of materials include photographs + + + align:start position:0% +studies of materials include photographs +of the microscopic structure structure + + align:start position:0% +of the microscopic structure structure + + + align:start position:0% +of the microscopic structure structure +of the material taken through some sort + + align:start position:0% +of the material taken through some sort + + + align:start position:0% +of the material taken through some sort +of microscope and the remarkable thing + + align:start position:0% +of microscope and the remarkable thing + + + align:start position:0% +of microscope and the remarkable thing +is that all of these studies really + + align:start position:0% +is that all of these studies really + + + align:start position:0% +is that all of these studies really +Trace back to this book here that we're + + align:start position:0% +Trace back to this book here that we're + + + align:start position:0% +Trace back to this book here that we're +looking at today to Robert Hook's + + align:start position:0% +looking at today to Robert Hook's + + + align:start position:0% +looking at today to Robert Hook's +micrographia there you have it so I just + + align:start position:0% +micrographia there you have it so I just + + + align:start position:0% +micrographia there you have it so I just +thought that was kind of cute you might + + align:start position:0% +thought that was kind of cute you might + + + align:start position:0% +thought that was kind of cute you might +enjoy that so so that was that all + + align:start position:0% +enjoy that so so that was that all + + + align:start position:0% +enjoy that so so that was that all +right oops let me get out of there yeah + + align:start position:0% +right oops let me get out of there yeah + + + align:start position:0% +right oops let me get out of there yeah +stop okay so let's go back to the Foams + + align:start position:0% +stop okay so let's go back to the Foams + + + align:start position:0% +stop okay so let's go back to the Foams +so I think last time we got us far as + + align:start position:0% +so I think last time we got us far as + + + align:start position:0% +so I think last time we got us far as +talking about the linear elastic + + align:start position:0% +talking about the linear elastic + + + align:start position:0% +talking about the linear elastic +behavior of Foams and modeling that uh + + align:start position:0% +behavior of Foams and modeling that uh + + + align:start position:0% +behavior of Foams and modeling that uh +but we didn't quite get to looking at + + align:start position:0% +but we didn't quite get to looking at + + + align:start position:0% +but we didn't quite get to looking at +the strength the compressive strength of + + align:start position:0% +the strength the compressive strength of + + + align:start position:0% +the strength the compressive strength of +the foam so I think we got as far as + + align:start position:0% +the foam so I think we got as far as + + + align:start position:0% +the foam so I think we got as far as +comparing the models with these + + align:start position:0% +comparing the models with these + + + align:start position:0% +comparing the models with these +equations here and these um plots of the + + align:start position:0% +equations here and these um plots of the + + + align:start position:0% +equations here and these um plots of the +data uh and what I wanted to pick up + + align:start position:0% +data uh and what I wanted to pick up + + + align:start position:0% +data uh and what I wanted to pick up +with today was looking at the + + align:start position:0% +with today was looking at the + + + align:start position:0% +with today was looking at the +compressive strength and we'll look at + + align:start position:0% +compressive strength and we'll look at + + + align:start position:0% +compressive strength and we'll look at +the fracture toughness as well uh in + + align:start position:0% +the fracture toughness as well uh in + + + align:start position:0% +the fracture toughness as well uh in +tension so we're going to start with + + align:start position:0% +tension so we're going to start with + + + align:start position:0% +tension so we're going to start with +nonlinear elasticity and the elastic + + align:start position:0% +nonlinear elasticity and the elastic + + + align:start position:0% +nonlinear elasticity and the elastic +collapse stress + + align:start position:0% + + + + align:start position:0% + +so if we have an open celled + + align:start position:0% +so if we have an open celled + + + align:start position:0% +so if we have an open celled +foam the uh derivation for the elastic + + align:start position:0% +foam the uh derivation for the elastic + + + align:start position:0% +foam the uh derivation for the elastic +collapse stress is really pretty + + align:start position:0% +collapse stress is really pretty + + + align:start position:0% +collapse stress is really pretty +straightforward we say we have the + + align:start position:0% +straightforward we say we have the + + + align:start position:0% +straightforward we say we have the +elastic collapse occurs when the cell + + align:start position:0% +elastic collapse occurs when the cell + + + align:start position:0% +elastic collapse occurs when the cell +walls Buckle so in this schematic here + + align:start position:0% +walls Buckle so in this schematic here + + + align:start position:0% +walls Buckle so in this schematic here +you can see the vertical cell walls have + + align:start position:0% +you can see the vertical cell walls have + + + align:start position:0% +you can see the vertical cell walls have +buckled and so there's going to be some + + align:start position:0% +buckled and so there's going to be some + + + align:start position:0% +buckled and so there's going to be some +Oiler load that that's related to that + + align:start position:0% +Oiler load that that's related to that + + + align:start position:0% +Oiler load that that's related to that +buckling and that's just the usual Oiler + + align:start position:0% +buckling and that's just the usual Oiler + + + align:start position:0% +buckling and that's just the usual Oiler +load n^2 the N constraint Factor pi^ 2 e + + align:start position:0% +load n^2 the N constraint Factor pi^ 2 e + + + align:start position:0% +load n^2 the N constraint Factor pi^ 2 e +this is going to be e of the solid I + + align:start position:0% +this is going to be e of the solid I + + + align:start position:0% +this is going to be e of the solid I +over + + align:start position:0% +over + + + align:start position:0% +over +l^2 the length of the member and then + + align:start position:0% +l^2 the length of the member and then + + + align:start position:0% +l^2 the length of the member and then +the stress that corresponds to that is + + align:start position:0% +the stress that corresponds to that is + + + align:start position:0% +the stress that corresponds to that is +just going to be proportional to that + + align:start position:0% +just going to be proportional to that + + + align:start position:0% +just going to be proportional to that +buckling load over the area of the cell + + align:start position:0% +buckling load over the area of the cell + + + align:start position:0% +buckling load over the area of the cell +which is just l^2 so just P critical + + align:start position:0% +which is just l^2 so just P critical + + + align:start position:0% +which is just l^2 so just P critical +over l^2 so that just goes as es s i is + + align:start position:0% +over l^2 so that just goes as es s i is + + + align:start position:0% +over l^2 so that just goes as es s i is +to go as T 4th because we have that + + align:start position:0% +to go as T 4th because we have that + + + align:start position:0% +to go as T 4th because we have that +square sectioned uh member and now this + + align:start position:0% +square sectioned uh member and now this + + + align:start position:0% +square sectioned uh member and now this +is going to be l^2 and that's an l^ S so + + align:start position:0% +is going to be l^2 and that's an l^ S so + + + align:start position:0% +is going to be l^2 and that's an l^ S so +that's L 4th and so if I combine all of + + align:start position:0% +that's L 4th and so if I combine all of + + + align:start position:0% +that's L 4th and so if I combine all of +that together I can say that the elastic + + align:start position:0% +that together I can say that the elastic + + + align:start position:0% +that together I can say that the elastic +buckling stress is going to be some + + align:start position:0% +buckling stress is going to be some + + + align:start position:0% +buckling stress is going to be some +constant and I think we're up to C4 now + + align:start position:0% +constant and I think we're up to C4 now + + + align:start position:0% +constant and I think we're up to C4 now +times the Young's modulus of the solid + + align:start position:0% +times the Young's modulus of the solid + + + align:start position:0% +times the Young's modulus of the solid +times the relative density of the foam + + align:start position:0% +times the relative density of the foam + + + align:start position:0% +times the relative density of the foam +squared okay so that's our + + align:start position:0% +squared okay so that's our + + + align:start position:0% +squared okay so that's our +equation for the elastic buckling stress + + align:start position:0% +equation for the elastic buckling stress + + + align:start position:0% +equation for the elastic buckling stress +and if you compare this with data you + + align:start position:0% +and if you compare this with data you + + + align:start position:0% +and if you compare this with data you +can make an estimate of what C4 is and + + align:start position:0% +can make an estimate of what C4 is and + + + align:start position:0% +can make an estimate of what C4 is and +we find that C4 is about + + align:start position:0% + + + + align:start position:0% + +05 and you can also say that 0.005 + + align:start position:0% +05 and you can also say that 0.005 + + + align:start position:0% +05 and you can also say that 0.005 +really corresponds to The Strain at + + align:start position:0% +really corresponds to The Strain at + + + align:start position:0% +really corresponds to The Strain at +which the buckling occurs because the + + align:start position:0% +which the buckling occurs because the + + + align:start position:0% +which the buckling occurs because the +Young's modulus goes as the constants + + align:start position:0% +Young's modulus goes as the constants + + + align:start position:0% +Young's modulus goes as the constants +one * e s * the relative density squ so + + align:start position:0% +one * e s * the relative density squ so + + + align:start position:0% +one * e s * the relative density squ so +the strain is just going to be the + + align:start position:0% +the strain is just going to be the + + + align:start position:0% +the strain is just going to be the +stress over the modulus so that does + + align:start position:0% +stress over the modulus so that does + + + align:start position:0% +stress over the modulus so that does +correspond to the The + + align:start position:0% + + + + align:start position:0% + +Strain so that's saying that that + + align:start position:0% +Strain so that's saying that that + + + align:start position:0% +Strain so that's saying that that +buckling compressive stress occurs at a + + align:start position:0% +buckling compressive stress occurs at a + + + align:start position:0% +buckling compressive stress occurs at a +strain of about + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +5% so that's open + + align:start position:0% +5% so that's open + + + align:start position:0% +5% so that's open +cells and then if we look at closed + + align:start position:0% +cells and then if we look at closed + + + align:start position:0% +cells and then if we look at closed +cells if you recall when we looked at + + align:start position:0% +cells if you recall when we looked at + + + align:start position:0% +cells if you recall when we looked at +the modui we looked at a couple of extra + + align:start position:0% +the modui we looked at a couple of extra + + + align:start position:0% +the modui we looked at a couple of extra +terms one was associated with face + + align:start position:0% +terms one was associated with face + + + align:start position:0% +terms one was associated with face +stretching for the modulus and the other + + align:start position:0% +stretching for the modulus and the other + + + align:start position:0% +stretching for the modulus and the other +was associated with the compression of + + align:start position:0% +was associated with the compression of + + + align:start position:0% +was associated with the compression of +the gas for the buckling the faces don't + + align:start position:0% +the gas for the buckling the faces don't + + + align:start position:0% +the gas for the buckling the faces don't +really contribute that much because + + align:start position:0% +really contribute that much because + + + align:start position:0% +really contribute that much because +typically the faces are very thin + + align:start position:0% +typically the faces are very thin + + + align:start position:0% +typically the faces are very thin +relative to the struts and because + + align:start position:0% +relative to the struts and because + + + align:start position:0% +relative to the struts and because +they're so thin they Buckle at a much + + align:start position:0% +they're so thin they Buckle at a much + + + align:start position:0% +they're so thin they Buckle at a much +lower load and they don't contribute too + + align:start position:0% +lower load and they don't contribute too + + + align:start position:0% +lower load and they don't contribute too +much so we're not going to worry about + + align:start position:0% +much so we're not going to worry about + + + align:start position:0% +much so we're not going to worry about +that contribution so I'm just going to + + align:start position:0% +that contribution so I'm just going to + + + align:start position:0% +that contribution so I'm just going to +say that the thickness of the face is + + align:start position:0% +say that the thickness of the face is + + + align:start position:0% +say that the thickness of the face is +often small + + align:start position:0% +often small + + + align:start position:0% +often small +compared to the + + align:start position:0% + + + + align:start position:0% + +edges and that really is from the + + align:start position:0% +edges and that really is from the + + + align:start position:0% +edges and that really is from the +surface tension in + + align:start position:0% + + + + align:start position:0% + +processing that draws material away from + + align:start position:0% +processing that draws material away from + + + align:start position:0% +processing that draws material away from +the face and into the edges + + align:start position:0% + + + + align:start position:0% + +there can be some contribution from the + + align:start position:0% +there can be some contribution from the + + + align:start position:0% +there can be some contribution from the +internal pressure so if the internal + + align:start position:0% +internal pressure so if the internal + + + align:start position:0% +internal pressure so if the internal +pressure is greater than atmospheric + + align:start position:0% +pressure is greater than atmospheric + + + align:start position:0% +pressure is greater than atmospheric +pressure then the cell walls are + + align:start position:0% +pressure then the cell walls are + + + align:start position:0% +pressure then the cell walls are +pre-tensioned and you'd have to account + + align:start position:0% +pre-tensioned and you'd have to account + + + align:start position:0% +pre-tensioned and you'd have to account +for that + + align:start position:0% + + + + align:start position:0% + +so the buckling would have to overcome + + align:start position:0% +so the buckling would have to overcome + + + align:start position:0% +so the buckling would have to overcome +that pressure as + + align:start position:0% + + + + align:start position:0% + +well so then you would have the buckling + + align:start position:0% +well so then you would have the buckling + + + align:start position:0% +well so then you would have the buckling +stress would just be what we have up + + align:start position:0% +stress would just be what we have up + + + align:start position:0% +stress would just be what we have up +there C4 * es s * a relative density + + align:start position:0% +there C4 * es s * a relative density + + + align:start position:0% +there C4 * es s * a relative density +squared and then we just add on that + + align:start position:0% +squared and then we just add on that + + + align:start position:0% +squared and then we just add on that +factor P KN minus P + + align:start position:0% +factor P KN minus P + + + align:start position:0% +factor P KN minus P +atmospheric the thing that the gas tends + + align:start position:0% +atmospheric the thing that the gas tends + + + align:start position:0% +atmospheric the thing that the gas tends +to affect more than the buckling stress + + align:start position:0% +to affect more than the buckling stress + + + align:start position:0% +to affect more than the buckling stress +though is the post collapse Behavior so + + align:start position:0% +though is the post collapse Behavior so + + + align:start position:0% +though is the post collapse Behavior so +let me just show you a couple of things + + align:start position:0% +let me just show you a couple of things + + + align:start position:0% +let me just show you a couple of things +here so here's some data for the elastic + + align:start position:0% +here so here's some data for the elastic + + + align:start position:0% +here so here's some data for the elastic +collapse stress and you can see on the + + align:start position:0% +collapse stress and you can see on the + + + align:start position:0% +collapse stress and you can see on the +y- AIS we've got the stress normalized + + align:start position:0% +y- AIS we've got the stress normalized + + + align:start position:0% +y- AIS we've got the stress normalized +by the Young's modulus of the solid and + + align:start position:0% +by the Young's modulus of the solid and + + + align:start position:0% +by the Young's modulus of the solid and +on the xaxis we've got the relative + + align:start position:0% +on the xaxis we've got the relative + + + align:start position:0% +on the xaxis we've got the relative +density and that solid line there that + + align:start position:0% +density and that solid line there that + + + align:start position:0% +density and that solid line there that +sort of solid dark line is that equation + + align:start position:0% +sort of solid dark line is that equation + + + align:start position:0% +sort of solid dark line is that equation +there which is the same as this one up + + align:start position:0% +there which is the same as this one up + + + align:start position:0% +there which is the same as this one up +here and you can see the data lie fairly + + align:start position:0% +here and you can see the data lie fairly + + + align:start position:0% +here and you can see the data lie fairly +close to that uh but what's interesting + + align:start position:0% +close to that uh but what's interesting + + + align:start position:0% +close to that uh but what's interesting +is if you look at the Oops why is this + + align:start position:0% +is if you look at the Oops why is this + + + align:start position:0% +is if you look at the Oops why is this +not + + align:start position:0% +not + + + align:start position:0% +not +working + + align:start position:0% +working + + + align:start position:0% +working +okay maybe my batteries finally died + + align:start position:0% +okay maybe my batteries finally died + + + align:start position:0% +okay maybe my batteries finally died +here if we look at the the post collapse + + align:start position:0% +here if we look at the the post collapse + + + align:start position:0% +here if we look at the the post collapse +Behavior you can see if these are the + + align:start position:0% +Behavior you can see if these are the + + + align:start position:0% +Behavior you can see if these are the +stress strain + + align:start position:0% +stress strain + + + align:start position:0% +stress strain +curves uh they they don't they're not + + align:start position:0% +curves uh they they don't they're not + + + align:start position:0% +curves uh they they don't they're not +flat here they have some um rise to them + + align:start position:0% +flat here they have some um rise to them + + + align:start position:0% +flat here they have some um rise to them +and this is a closed cell foam and you + + align:start position:0% +and this is a closed cell foam and you + + + align:start position:0% +and this is a closed cell foam and you +can imagine as you're compressing the + + align:start position:0% +can imagine as you're compressing the + + + align:start position:0% +can imagine as you're compressing the +closed cell foam you're reducing the + + align:start position:0% +closed cell foam you're reducing the + + + align:start position:0% +closed cell foam you're reducing the +volume of the cell and as you're doing + + align:start position:0% +volume of the cell and as you're doing + + + align:start position:0% +volume of the cell and as you're doing +that you're increasing the pressure + + align:start position:0% +that you're increasing the pressure + + + align:start position:0% +that you're increasing the pressure +inside the cell from the gas and you can + + align:start position:0% +inside the cell from the gas and you can + + + align:start position:0% +inside the cell from the gas and you can +calculate what that is and I'll I'll do + + align:start position:0% +calculate what that is and I'll I'll do + + + align:start position:0% +calculate what that is and I'll I'll do +that in a second and if you subtract off + + align:start position:0% +that in a second and if you subtract off + + + align:start position:0% +that in a second and if you subtract off +that gas pressure contribution that + + align:start position:0% +that gas pressure contribution that + + + align:start position:0% +that gas pressure contribution that +works out to this line here then these + + align:start position:0% +works out to this line here then these + + + align:start position:0% +works out to this line here then these +lines will be more flat like this okay + + align:start position:0% +lines will be more flat like this okay + + + align:start position:0% +lines will be more flat like this okay +so and we already really pretty much + + align:start position:0% +so and we already really pretty much + + + align:start position:0% +so and we already really pretty much +worked out that gas + + align:start position:0% + + + + align:start position:0% + +contribution so I'll just say for the + + align:start position:0% +contribution so I'll just say for the + + + align:start position:0% +contribution so I'll just say for the +Post collapse + + align:start position:0% + + + + align:start position:0% + +Behavior Uh the stress Rises due to the + + align:start position:0% +Behavior Uh the stress Rises due to the + + + align:start position:0% +Behavior Uh the stress Rises due to the +gas + + align:start position:0% + + + + align:start position:0% + +compression and that's as long as the + + align:start position:0% +compression and that's as long as the + + + align:start position:0% +compression and that's as long as the +faces don't rupt + + align:start position:0% + + + + align:start position:0% + +so if you had aeric foam typically they + + align:start position:0% +so if you had aeric foam typically they + + + align:start position:0% +so if you had aeric foam typically they +don't + + align:start position:0% + + + + align:start position:0% + +rupture and what we had worked out + + align:start position:0% +rupture and what we had worked out + + + align:start position:0% +rupture and what we had worked out +before was that that pressure we called + + align:start position:0% +before was that that pressure we called + + + align:start position:0% +before was that that pressure we called +it P prime it was P KN minus P + + align:start position:0% +it P prime it was P KN minus P + + + align:start position:0% +it P prime it was P KN minus P +atmospheric that was equal to um P KN + + align:start position:0% +atmospheric that was equal to um P KN + + + align:start position:0% +atmospheric that was equal to um P KN +times + + align:start position:0% +times + + + align:start position:0% +times +oops time the amount of strain + + align:start position:0% +oops time the amount of strain + + + align:start position:0% +oops time the amount of strain +Epsilon Time 1 - 2 * the quon's ratio + + align:start position:0% +Epsilon Time 1 - 2 * the quon's ratio + + + align:start position:0% +Epsilon Time 1 - 2 * the quon's ratio +divided by 1 - Epsilon * 1 - 2 + + align:start position:0% +divided by 1 - Epsilon * 1 - 2 + + + align:start position:0% +divided by 1 - Epsilon * 1 - 2 +muus the relative + + align:start position:0% + + + + align:start position:0% + +density and once you get to the uh + + align:start position:0% +density and once you get to the uh + + + align:start position:0% +density and once you get to the uh +buckling stress then the pon ratio + + align:start position:0% +buckling stress then the pon ratio + + + align:start position:0% +buckling stress then the pon ratio +becomes zero + + align:start position:0% + + + + align:start position:0% + +so if you take a foam so I brought a + + align:start position:0% +so if you take a foam so I brought a + + + align:start position:0% +so if you take a foam so I brought a +little foam in so we can play around + + align:start position:0% +little foam in so we can play around + + + align:start position:0% +little foam in so we can play around +with this one so if you take a foam like + + align:start position:0% +with this one so if you take a foam like + + + align:start position:0% +with this one so if you take a foam like +this and you compress it once you've + + align:start position:0% +this and you compress it once you've + + + align:start position:0% +this and you compress it once you've +buckled it like this it's not getting + + align:start position:0% +buckled it like this it's not getting + + + align:start position:0% +buckled it like this it's not getting +any wider this way and part of the + + align:start position:0% +any wider this way and part of the + + + align:start position:0% +any wider this way and part of the +reason for that is you've got all these + + align:start position:0% +reason for that is you've got all these + + + align:start position:0% +reason for that is you've got all these +pores in here and the cells just + + align:start position:0% +pores in here and the cells just + + + align:start position:0% +pores in here and the cells just +collapse into the pores they don't you + + align:start position:0% +collapse into the pores they don't you + + + align:start position:0% +collapse into the pores they don't you +know they don't really need to move out + + align:start position:0% +know they don't really need to move out + + + align:start position:0% +know they don't really need to move out +sideways so you can smoos that yourself + + align:start position:0% +sideways so you can smoos that yourself + + + align:start position:0% +sideways so you can smoos that yourself +and try to convince yourself but the + + align:start position:0% +and try to convince yourself but the + + + align:start position:0% +and try to convince yourself but the +poson ratio is just zero yes Matt is + + align:start position:0% +poson ratio is just zero yes Matt is + + + align:start position:0% +poson ratio is just zero yes Matt is +there um are + + align:start position:0% +there um are + + + align:start position:0% +there um are +these uh I guess I would imagine stra + + align:start position:0% +these uh I guess I would imagine stra + + + align:start position:0% +these uh I guess I would imagine stra +rate comes into effect in the gas + + align:start position:0% +rate comes into effect in the gas + + + align:start position:0% +rate comes into effect in the gas +contribution yeah so so there was a + + align:start position:0% +contribution yeah so so there was a + + + align:start position:0% +contribution yeah so so there was a +strain rate effect with these things but + + align:start position:0% +strain rate effect with these things but + + + align:start position:0% +strain rate effect with these things but +I wasn't going to get into that here if + + align:start position:0% +I wasn't going to get into that here if + + + align:start position:0% +I wasn't going to get into that here if +you look in the book it's described in + + align:start position:0% +you look in the book it's described in + + + align:start position:0% +you look in the book it's described in +the book so there's I think there's two + + align:start position:0% +the book so there's I think there's two + + + align:start position:0% +the book so there's I think there's two +things one is that the solid itself can + + align:start position:0% +things one is that the solid itself can + + + align:start position:0% +things one is that the solid itself can +have a rate dependency and then there + + align:start position:0% +have a rate dependency and then there + + + align:start position:0% +have a rate dependency and then there +could be something + + align:start position:0% +could be something + + + align:start position:0% +could be something +connected yeah I mean I'm not going to + + align:start position:0% +connected yeah I mean I'm not going to + + + align:start position:0% +connected yeah I mean I'm not going to +go into that here but one one could look + + align:start position:0% +go into that here but one one could look + + + align:start position:0% +go into that here but one one could look +at that + + align:start position:0% +at that + + + align:start position:0% +at that +so okay so let me just write down one + + align:start position:0% +so okay so let me just write down one + + + align:start position:0% +so okay so let me just write down one +more thing here U because if we let new + + align:start position:0% +more thing here U because if we let new + + + align:start position:0% +more thing here U because if we let new +be zero then this thing here becomes + + align:start position:0% + + + + align:start position:0% + +simpler so we could say the stress post + + align:start position:0% +simpler so we could say the stress post + + + align:start position:0% +simpler so we could say the stress post +collapse as a function of + + align:start position:0% +collapse as a function of + + + align:start position:0% +collapse as a function of +strain would be our buckling stress + + align:start position:0% + + + + align:start position:0% + +and then plus this Factor + + align:start position:0% +and then plus this Factor + + + align:start position:0% +and then plus this Factor +here + + align:start position:0% + + + + align:start position:0% + +oops so that curve on the on the + + align:start position:0% +oops so that curve on the on the + + + align:start position:0% +oops so that curve on the on the +bottom over here if this is the stress + + align:start position:0% +bottom over here if this is the stress + + + align:start position:0% +bottom over here if this is the stress +strin curve this little dashed line here + + align:start position:0% +strin curve this little dashed line here + + + align:start position:0% +strin curve this little dashed line here +that's the gas contribution and that is + + align:start position:0% +that's the gas contribution and that is + + + align:start position:0% +that's the gas contribution and that is +this term here okay so you can kind of + + align:start position:0% +this term here okay so you can kind of + + + align:start position:0% +this term here okay so you can kind of +see how the shape of the curves reflects + + align:start position:0% +see how the shape of the curves reflects + + + align:start position:0% +see how the shape of the curves reflects +that gas contribution and when you + + align:start position:0% +that gas contribution and when you + + + align:start position:0% +that gas contribution and when you +subtract it out you get pretty much a + + align:start position:0% +subtract it out you get pretty much a + + + align:start position:0% +subtract it out you get pretty much a +horizontal Plateau over here + + align:start position:0% +horizontal Plateau over here + + + align:start position:0% +horizontal Plateau over here +okay are we + + align:start position:0% +okay are we + + + align:start position:0% +okay are we +happy + + align:start position:0% +happy + + + align:start position:0% +happy +yeah this is for the closed cell because + + align:start position:0% +yeah this is for the closed cell because + + + align:start position:0% +yeah this is for the closed cell because +the closed cell are the ones that are + + align:start position:0% +the closed cell are the ones that are + + + align:start position:0% +the closed cell are the ones that are +going to have the gas pressure right if + + align:start position:0% +going to have the gas pressure right if + + + align:start position:0% +going to have the gas pressure right if +it's open cells the gas can just move + + align:start position:0% +it's open cells the gas can just move + + + align:start position:0% +it's open cells the gas can just move +out of the + + align:start position:0% +out of the + + + align:start position:0% +out of the +cells oh oh sorry but that was sorry + + align:start position:0% +cells oh oh sorry but that was sorry + + + align:start position:0% +cells oh oh sorry but that was sorry +that was to show you that the plon ratio + + align:start position:0% +that was to show you that the plon ratio + + + align:start position:0% +that was to show you that the plon ratio +was zero and that's true for both of + + align:start position:0% +was zero and that's true for both of + + + align:start position:0% +was zero and that's true for both of +them yeah + + align:start position:0% + + + + align:start position:0% + +so then we can look at the plastic + + align:start position:0% +so then we can look at the plastic + + + align:start position:0% +so then we can look at the plastic +collapse stress say we had a a metal + + align:start position:0% +collapse stress say we had a a metal + + + align:start position:0% +collapse stress say we had a a metal +foam and we do a calculation a little + + align:start position:0% +foam and we do a calculation a little + + + align:start position:0% +foam and we do a calculation a little +bit like the one we did for the + + align:start position:0% +bit like the one we did for the + + + align:start position:0% +bit like the one we did for the +Honeycombs too so we say the failure + + align:start position:0% +Honeycombs too so we say the failure + + + align:start position:0% +Honeycombs too so we say the failure +occurs when the applied moment equals + + align:start position:0% +occurs when the applied moment equals + + + align:start position:0% +occurs when the applied moment equals +the plastic + + align:start position:0% + + + + align:start position:0% + +moment and the applied moment is + + align:start position:0% +moment and the applied moment is + + + align:start position:0% +moment and the applied moment is +proportional to the applied stress times + + align:start position:0% +proportional to the applied stress times + + + align:start position:0% +proportional to the applied stress times +a length + + align:start position:0% + + + + align:start position:0% + +cubed so I'm going to call that applied + + align:start position:0% +cubed so I'm going to call that applied + + + align:start position:0% +cubed so I'm going to call that applied +stress our our strength Sigma star + + align:start position:0% +stress our our strength Sigma star + + + align:start position:0% +stress our our strength Sigma star +plastic times a length cubed so if you + + align:start position:0% +plastic times a length cubed so if you + + + align:start position:0% +plastic times a length cubed so if you +think of say the little schematic up + + align:start position:0% +think of say the little schematic up + + + align:start position:0% +think of say the little schematic up +here the force is going to go as stress + + align:start position:0% +here the force is going to go as stress + + + align:start position:0% +here the force is going to go as stress +times a length squared and the moment is + + align:start position:0% +times a length squared and the moment is + + + align:start position:0% +times a length squared and the moment is +going to be a force times a length so + + align:start position:0% +going to be a force times a length so + + + align:start position:0% +going to be a force times a length so +it's the force time the length cubed + + align:start position:0% +it's the force time the length cubed + + + align:start position:0% +it's the force time the length cubed +okay so rather sorry it's the stress + + align:start position:0% +okay so rather sorry it's the stress + + + align:start position:0% +okay so rather sorry it's the stress +times length cubed um and then the + + align:start position:0% +times length cubed um and then the + + + align:start position:0% +times length cubed um and then the +fracture rather the plastic moment + + align:start position:0% +fracture rather the plastic moment + + + align:start position:0% +fracture rather the plastic moment +goes as the yield + + align:start position:0% +goes as the yield + + + align:start position:0% +goes as the yield +strength times the thickness + + align:start position:0% + + + + align:start position:0% + +cubed and then if I just combine + + align:start position:0% + + + + align:start position:0% + +those I get that the plastic collapse + + align:start position:0% +those I get that the plastic collapse + + + align:start position:0% +those I get that the plastic collapse +stress in compression is another + + align:start position:0% +stress in compression is another + + + align:start position:0% +stress in compression is another +constant I'm going to call it + + align:start position:0% +constant I'm going to call it + + + align:start position:0% +constant I'm going to call it +C5 times the yield + + align:start position:0% +C5 times the yield + + + align:start position:0% +C5 times the yield +strength times the relative + + align:start position:0% +strength times the relative + + + align:start position:0% +strength times the relative +density to the three halfes power + + align:start position:0% + + + + align:start position:0% + +and if we look at data we find that this + + align:start position:0% +and if we look at data we find that this + + + align:start position:0% +and if we look at data we find that this +constant is about equal + + align:start position:0% + + + + align:start position:0% + +to3 and if I go to the next slide oops I + + align:start position:0% +to3 and if I go to the next slide oops I + + + align:start position:0% +to3 and if I go to the next slide oops I +missed one I think uh so here's a plot + + align:start position:0% +missed one I think uh so here's a plot + + + align:start position:0% +missed one I think uh so here's a plot +of the yield strength of the or the you + + align:start position:0% +of the yield strength of the or the you + + + align:start position:0% +of the yield strength of the or the you +know the plastic collapse strength of + + align:start position:0% +know the plastic collapse strength of + + + align:start position:0% +know the plastic collapse strength of +the foam divided by the yield strength + + align:start position:0% +the foam divided by the yield strength + + + align:start position:0% +the foam divided by the yield strength +of the solid plot us against the + + align:start position:0% +of the solid plot us against the + + + align:start position:0% +of the solid plot us against the +relative density and that dark bold line + + align:start position:0% +relative density and that dark bold line + + + align:start position:0% +relative density and that dark bold line +is this equation here and you can see + + align:start position:0% +is this equation here and you can see + + + align:start position:0% +is this equation here and you can see +the data like pretty well on that line + + align:start position:0% +the data like pretty well on that line + + + align:start position:0% +the data like pretty well on that line +there's one data set that's a little bit + + align:start position:0% +there's one data set that's a little bit + + + align:start position:0% +there's one data set that's a little bit +above the line but you can see the slope + + align:start position:0% +above the line but you can see the slope + + + align:start position:0% +above the line but you can see the slope +of that data set is still about three + + align:start position:0% +of that data set is still about three + + + align:start position:0% +of that data set is still about three +halves + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% + + + + align:start position:0% + +okay and the same as in the Honeycombs + + align:start position:0% +okay and the same as in the Honeycombs + + + align:start position:0% +okay and the same as in the Honeycombs +we could say that we could get elastic + + align:start position:0% +we could say that we could get elastic + + + align:start position:0% +we could say that we could get elastic +collapse before the plastic collapse if + + align:start position:0% +collapse before the plastic collapse if + + + align:start position:0% +collapse before the plastic collapse if +we were at a low density you can get the + + align:start position:0% +we were at a low density you can get the + + + align:start position:0% +we were at a low density you can get the +same thing in the Foams and you + + align:start position:0% +same thing in the Foams and you + + + align:start position:0% +same thing in the Foams and you +calculate out what the critical relative + + align:start position:0% +calculate out what the critical relative + + + align:start position:0% +calculate out what the critical relative +density is for that the same kind of way + + align:start position:0% +density is for that the same kind of way + + + align:start position:0% +density is for that the same kind of way +so we could say we can get elastic + + align:start position:0% + + + + align:start position:0% + +collapse precedes the plastic + + align:start position:0% + + + + align:start position:0% + +collapse if the elastic buckling stress + + align:start position:0% +collapse if the elastic buckling stress + + + align:start position:0% +collapse if the elastic buckling stress +is less than the plastic collapse + + align:start position:0% +is less than the plastic collapse + + + align:start position:0% +is less than the plastic collapse +stress so all we do is + + align:start position:0% +stress so all we do is + + + align:start position:0% +stress so all we do is +make those two things + + align:start position:0% +make those two things + + + align:start position:0% +make those two things +equal to figure out the critical + + align:start position:0% +equal to figure out the critical + + + align:start position:0% +equal to figure out the critical +relative density where you get the + + align:start position:0% +relative density where you get the + + + align:start position:0% +relative density where you get the +transition from one to the + + align:start position:0% + + + + align:start position:0% + +other so the relative density has to be + + align:start position:0% +other so the relative density has to be + + + align:start position:0% +other so the relative density has to be +less than 36 times the yield strength of + + align:start position:0% +less than 36 times the yield strength of + + + align:start position:0% +less than 36 times the yield strength of +the solid over the Young's modulus of + + align:start position:0% +the solid over the Young's modulus of + + + align:start position:0% +the solid over the Young's modulus of +the solid squared in order to get + + align:start position:0% +the solid squared in order to get + + + align:start position:0% +the solid squared in order to get +buckling before um + + align:start position:0% +buckling before um + + + align:start position:0% +buckling before um +yielding and let's see where can I put + + align:start position:0% + + + + align:start position:0% + +that so for rigid + + align:start position:0% +that so for rigid + + + align:start position:0% +that so for rigid +polymers that ratio of the strength of + + align:start position:0% +polymers that ratio of the strength of + + + align:start position:0% +polymers that ratio of the strength of +the solid over the modulus of the solid + + align:start position:0% +the solid over the modulus of the solid + + + align:start position:0% +the solid over the modulus of the solid +is about 1 + + align:start position:0% + + + + align:start position:0% + +over3 and so the critical + + align:start position:0% +over3 and so the critical + + + align:start position:0% +over3 and so the critical +relative density for the transition is + + align:start position:0% +relative density for the transition is + + + align:start position:0% +relative density for the transition is +about + + align:start position:0% +about + + + align:start position:0% +about +004 so you'd have to have a pretty low + + align:start position:0% +004 so you'd have to have a pretty low + + + align:start position:0% +004 so you'd have to have a pretty low +density foam but it's possible and for + + align:start position:0% + + + + align:start position:0% + +metals that + + align:start position:0% +metals that + + + align:start position:0% +metals that +ratio is about 1 in a + + align:start position:0% + + + + align:start position:0% + +th000 and then the critical transition + + align:start position:0% +th000 and then the critical transition + + + align:start position:0% +th000 and then the critical transition +density is less than 10us 5 so + + align:start position:0% +density is less than 10us 5 so + + + align:start position:0% +density is less than 10us 5 so +essentially it never happens for the + + align:start position:0% +essentially it never happens for the + + + align:start position:0% +essentially it never happens for the +metal foams + + align:start position:0% + + + + align:start position:0% + +see go over + + align:start position:0% + + + + align:start position:0% + +here then for the Clos cell Foams we + + align:start position:0% +here then for the Clos cell Foams we + + + align:start position:0% +here then for the Clos cell Foams we +could include the terms for face + + align:start position:0% +could include the terms for face + + + align:start position:0% +could include the terms for face +stretching and for the gas but in + + align:start position:0% +stretching and for the gas but in + + + align:start position:0% +stretching and for the gas but in +practice the faces don't really + + align:start position:0% +practice the faces don't really + + + align:start position:0% +practice the faces don't really +contribute very much and typically for + + align:start position:0% +contribute very much and typically for + + + align:start position:0% +contribute very much and typically for +Foams like say metal Foams or a rigid + + align:start position:0% +Foams like say metal Foams or a rigid + + + align:start position:0% +Foams like say metal Foams or a rigid +polymer that had a yield point the faces + + align:start position:0% +polymer that had a yield point the faces + + + align:start position:0% +polymer that had a yield point the faces +rupture and then if the faces rupture + + align:start position:0% +rupture and then if the faces rupture + + + align:start position:0% +rupture and then if the faces rupture +then you don't get the gas compression + + align:start position:0% +then you don't get the gas compression + + + align:start position:0% +then you don't get the gas compression +term either so I'll just write the full + + align:start position:0% +term either so I'll just write the full + + + align:start position:0% +term either so I'll just write the full +thing down but typically you don't need + + align:start position:0% +thing down but typically you don't need + + + align:start position:0% +thing down but typically you don't need +to use it + + align:start position:0% + + + + align:start position:0% + +yeah that's right + + align:start position:0% + + + + align:start position:0% + +so the first term would be from the + + align:start position:0% +so the first term would be from the + + + align:start position:0% +so the first term would be from the +edges + + align:start position:0% + + + + align:start position:0% + +bending and the second term would be + + align:start position:0% +bending and the second term would be + + + align:start position:0% +bending and the second term would be +from the faces + + align:start position:0% + + + + align:start position:0% + +stretching and this would be from the + + align:start position:0% +stretching and this would be from the + + + align:start position:0% +stretching and this would be from the +gas but in practice the first term is + + align:start position:0% +gas but in practice the first term is + + + align:start position:0% +gas but in practice the first term is +really the only one that's um + + align:start position:0% +really the only one that's um + + + align:start position:0% +really the only one that's um +significant + + align:start position:0% + + + + align:start position:0% + +so the for closed cell Foams this + + align:start position:0% +so the for closed cell Foams this + + + align:start position:0% +so the for closed cell Foams this +equation works pretty well too the same + + align:start position:0% +equation works pretty well too the same + + + align:start position:0% +equation works pretty well too the same +one is for the open cell foams + + align:start position:0% + + + + align:start position:0% + +d + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% + + + + align:start position:0% + +okay so if we had a say a ceramic foam + + align:start position:0% +okay so if we had a say a ceramic foam + + + align:start position:0% +okay so if we had a say a ceramic foam +that was brittle it' be a brittle + + align:start position:0% +that was brittle it' be a brittle + + + align:start position:0% +that was brittle it' be a brittle +crushing strength and then we get + + align:start position:0% +crushing strength and then we get + + + align:start position:0% +crushing strength and then we get +failure when the applied moment m + + align:start position:0% +failure when the applied moment m + + + align:start position:0% +failure when the applied moment m +is equal to the fracture moment MF and + + align:start position:0% +is equal to the fracture moment MF and + + + align:start position:0% +is equal to the fracture moment MF and +this works very similar to the plastic + + align:start position:0% +this works very similar to the plastic + + + align:start position:0% +this works very similar to the plastic +yield + + align:start position:0% +yield + + + align:start position:0% +yield +strength uh so we find the applied + + align:start position:0% +strength uh so we find the applied + + + align:start position:0% +strength uh so we find the applied +moment goes as the global stress times + + align:start position:0% +moment goes as the global stress times + + + align:start position:0% +moment goes as the global stress times +the length cubed and the fracture moment + + align:start position:0% +the length cubed and the fracture moment + + + align:start position:0% +the length cubed and the fracture moment +goes as the cell wall strength times the + + align:start position:0% +goes as the cell wall strength times the + + + align:start position:0% +goes as the cell wall strength times the +length times the cell wall thickness + + align:start position:0% + + + + align:start position:0% + +cubed so the brittle crushing strength + + align:start position:0% +cubed so the brittle crushing strength + + + align:start position:0% +cubed so the brittle crushing strength +goes as another constant let's call let + + align:start position:0% +goes as another constant let's call let + + + align:start position:0% +goes as another constant let's call let +C6 times the wall + + align:start position:0% +C6 times the wall + + + align:start position:0% +C6 times the wall +strength times the relative density to + + align:start position:0% +strength times the relative density to + + + align:start position:0% +strength times the relative density to +the three Hales + + align:start position:0% + + + + align:start position:0% + +again and C6 is about equal + + align:start position:0% + + + + align:start position:0% + +to2 and typically ceramic Foams have + + align:start position:0% +to2 and typically ceramic Foams have + + + align:start position:0% +to2 and typically ceramic Foams have +open cells so I'm just going to leave it + + align:start position:0% +open cells so I'm just going to leave it + + + align:start position:0% +open cells so I'm just going to leave it +at the open cell um formula there so + + align:start position:0% +at the open cell um formula there so + + + align:start position:0% +at the open cell um formula there so +there's one last thing for the + + align:start position:0% +there's one last thing for the + + + align:start position:0% +there's one last thing for the +compressive behavior and that's the + + align:start position:0% +compressive behavior and that's the + + + align:start position:0% +compressive behavior and that's the +densification strain and we just have an + + align:start position:0% +densification strain and we just have an + + + align:start position:0% +densification strain and we just have an +empirical relationship for the + + align:start position:0% +empirical relationship for the + + + align:start position:0% +empirical relationship for the +densification + + align:start position:0% + + + + align:start position:0% + +strain so if you compress the foam and + + align:start position:0% +strain so if you compress the foam and + + + align:start position:0% +strain so if you compress the foam and +you get to very large strains then the + + align:start position:0% +you get to very large strains then the + + + align:start position:0% +you get to very large strains then the +cell walls start to touch and the stress + + align:start position:0% +cell walls start to touch and the stress + + + align:start position:0% +cell walls start to touch and the stress +starts to rise steeply and there's some + + align:start position:0% +starts to rise steeply and there's some + + + align:start position:0% +starts to rise steeply and there's some +strain at which that occurs and we call + + align:start position:0% +strain at which that occurs and we call + + + align:start position:0% +strain at which that occurs and we call +that the densification strain and in the + + align:start position:0% +that the densification strain and in the + + + align:start position:0% +that the densification strain and in the +limit the modulus at that point would go + + align:start position:0% +limit the modulus at that point would go + + + align:start position:0% +limit the modulus at that point would go +to the modulus of the solid if you could + + align:start position:0% +to the modulus of the solid if you could + + + align:start position:0% +to the modulus of the solid if you could +completely squeeze all the pores out the + + align:start position:0% +completely squeeze all the pores out the + + + align:start position:0% +completely squeeze all the pores out the +stiffness of that uh would go to the + + align:start position:0% +stiffness of that uh would go to the + + + align:start position:0% +stiffness of that uh would go to the +modulus of the solid and you might + + align:start position:0% +modulus of the solid and you might + + + align:start position:0% +modulus of the solid and you might +expect that that densification strain is + + align:start position:0% +expect that that densification strain is + + + align:start position:0% +expect that that densification strain is +just one minus the relative density but + + align:start position:0% +just one minus the relative density but + + + align:start position:0% +just one minus the relative density but +it actually occurs at a slightly smaller + + align:start position:0% + + + + align:start position:0% + +strain so a large compressive stress or + + align:start position:0% +strain so a large compressive stress or + + + align:start position:0% +strain so a large compressive stress or +strain I guess we could say the cell + + align:start position:0% +strain I guess we could say the cell + + + align:start position:0% +strain I guess we could say the cell +walls touch and we start to get this + + align:start position:0% +walls touch and we start to get this + + + align:start position:0% +walls touch and we start to get this +densification + + align:start position:0% + + + + align:start position:0% + +so the modulus and the limit would go to + + align:start position:0% +so the modulus and the limit would go to + + + align:start position:0% +so the modulus and the limit would go to +the modulus of the + + align:start position:0% + + + + align:start position:0% + +solid and you might expect that the + + align:start position:0% +solid and you might expect that the + + + align:start position:0% +solid and you might expect that the +densification strain was just equal to + + align:start position:0% +densification strain was just equal to + + + align:start position:0% +densification strain was just equal to +one minus the relative + + align:start position:0% +one minus the relative + + + align:start position:0% +one minus the relative +density but it occurs at a little bit + + align:start position:0% +density but it occurs at a little bit + + + align:start position:0% +density but it occurs at a little bit +less than that so empirically we find + + align:start position:0% +less than that so empirically we find + + + align:start position:0% +less than that so empirically we find +that it's just one - + + align:start position:0% +that it's just one - + + + align:start position:0% +that it's just one - +1.4 times the relative + + align:start position:0% +1.4 times the relative + + + align:start position:0% +1.4 times the relative +density okay okay and then I have this + + align:start position:0% +density okay okay and then I have this + + + align:start position:0% +density okay okay and then I have this +plot here which is really just fitting + + align:start position:0% +plot here which is really just fitting + + + align:start position:0% +plot here which is really just fitting +aligned to that data for the + + align:start position:0% +aligned to that data for the + + + align:start position:0% +aligned to that data for the +densification + + align:start position:0% + + + + align:start position:0% + +strain so those equations describe the + + align:start position:0% +strain so those equations describe the + + + align:start position:0% +strain so those equations describe the +compressive stress or the compressive + + align:start position:0% +compressive stress or the compressive + + + align:start position:0% +compressive stress or the compressive +behavior of the foam so we've got the + + align:start position:0% +behavior of the foam so we've got the + + + align:start position:0% +behavior of the foam so we've got the +moduli we've got the three compressive + + align:start position:0% +moduli we've got the three compressive + + + align:start position:0% +moduli we've got the three compressive +uh strengths and we've got the + + align:start position:0% +uh strengths and we've got the + + + align:start position:0% +uh strengths and we've got the +densification + + align:start position:0% + + + + align:start position:0% + +strain so what we're going to do later + + align:start position:0% +strain so what we're going to do later + + + align:start position:0% +strain so what we're going to do later +on in the course is we'll use those + + align:start position:0% +on in the course is we'll use those + + + align:start position:0% +on in the course is we'll use those +models to look at we can use Foams and + + align:start position:0% +models to look at we can use Foams and + + + align:start position:0% +models to look at we can use Foams and +things like sandwich panels and looking + + align:start position:0% +things like sandwich panels and looking + + + align:start position:0% +things like sandwich panels and looking +at energy absorption and we'll also look + + align:start position:0% +at energy absorption and we'll also look + + + align:start position:0% +at energy absorption and we'll also look +at these equations in terms of some + + align:start position:0% +at these equations in terms of some + + + align:start position:0% +at these equations in terms of some +biomedical materials looking at tricular + + align:start position:0% +biomedical materials looking at tricular + + + align:start position:0% +biomedical materials looking at tricular +bone and looking at tissue engineering + + align:start position:0% +bone and looking at tissue engineering + + + align:start position:0% +bone and looking at tissue engineering +scaffolds so there's one last property I + + align:start position:0% +scaffolds so there's one last property I + + + align:start position:0% +scaffolds so there's one last property I +wanted to go over and that's the + + align:start position:0% +wanted to go over and that's the + + + align:start position:0% +wanted to go over and that's the +fracture toughness so if we were pulling + + align:start position:0% +fracture toughness so if we were pulling + + + align:start position:0% +fracture toughness so if we were pulling +the foam in tension and we had a crack + + align:start position:0% +the foam in tension and we had a crack + + + align:start position:0% +the foam in tension and we had a crack +in the foam we'd want to know what the + + align:start position:0% +in the foam we'd want to know what the + + + align:start position:0% +in the foam we'd want to know what the +fracture toughness would be for a + + align:start position:0% +fracture toughness would be for a + + + align:start position:0% +fracture toughness would be for a +brittle foam and this follows the same + + align:start position:0% +brittle foam and this follows the same + + + align:start position:0% +brittle foam and this follows the same +sort of argument as we had for the + + align:start position:0% +sort of argument as we had for the + + + align:start position:0% +sort of argument as we had for the +honeycomb so all these equations really + + align:start position:0% +honeycomb so all these equations really + + + align:start position:0% +honeycomb so all these equations really +are just following the same kinds of + + align:start position:0% +are just following the same kinds of + + + align:start position:0% +are just following the same kinds of +arguments + + align:start position:0% +arguments + + + align:start position:0% +arguments +but you can kind of see how having the + + align:start position:0% +but you can kind of see how having the + + + align:start position:0% +but you can kind of see how having the +honeycomb calculations it it makes it + + align:start position:0% +honeycomb calculations it it makes it + + + align:start position:0% +honeycomb calculations it it makes it +easier to to do the foam + + align:start position:0% +easier to to do the foam + + + align:start position:0% +easier to to do the foam +ones so we'll do the fracture toughness + + align:start position:0% +ones so we'll do the fracture toughness + + + align:start position:0% +ones so we'll do the fracture toughness +calculation and then I wanted to talk a + + align:start position:0% +calculation and then I wanted to talk a + + + align:start position:0% +calculation and then I wanted to talk a +little bit about material selection and + + align:start position:0% +little bit about material selection and + + + align:start position:0% +little bit about material selection and +selection charts for Foams so that's + + align:start position:0% +selection charts for Foams so that's + + + align:start position:0% +selection charts for Foams so that's +less equation + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% + + + + align:start position:0% + +okay and we're just going to look at + + align:start position:0% +okay and we're just going to look at + + + align:start position:0% +okay and we're just going to look at +open cells + + align:start position:0% + + + + align:start position:0% + +here so imagine we have a crack of + + align:start position:0% +here so imagine we have a crack of + + + align:start position:0% +here so imagine we have a crack of +length 2 a + + align:start position:0% + + + + align:start position:0% + +and we have some uh remote stress + + align:start position:0% +and we have some uh remote stress + + + align:start position:0% +and we have some uh remote stress +applied so a remote tensile + + align:start position:0% + + + + align:start position:0% + +stress so I'm going to call that Sigma + + align:start position:0% +stress so I'm going to call that Sigma + + + align:start position:0% +stress so I'm going to call that Sigma +Infinity the far away stress and then we + + align:start position:0% +Infinity the far away stress and then we + + + align:start position:0% +Infinity the far away stress and then we +have a local stress on the cell + + align:start position:0% +have a local stress on the cell + + + align:start position:0% +have a local stress on the cell +walls I'm going to call that Sigma local + + align:start position:0% +walls I'm going to call that Sigma local + + + align:start position:0% +walls I'm going to call that Sigma local +so I have a little schematic that kind + + align:start position:0% +so I have a little schematic that kind + + + align:start position:0% +so I have a little schematic that kind +of shows what we're doing so we're + + align:start position:0% +of shows what we're doing so we're + + + align:start position:0% +of shows what we're doing so we're +pulling on it there's some crack the + + align:start position:0% +pulling on it there's some crack the + + + align:start position:0% +pulling on it there's some crack the +crack length is large compared to the + + align:start position:0% +crack length is large compared to the + + + align:start position:0% +crack length is large compared to the +cell size + + align:start position:0% +cell size + + + align:start position:0% +cell size +and we want to know what the fracture + + align:start position:0% +and we want to know what the fracture + + + align:start position:0% +and we want to know what the fracture +toughness is so we can say from fracture + + align:start position:0% +toughness is so we can say from fracture + + + align:start position:0% +toughness is so we can say from fracture +mechanics the local stress is going to + + align:start position:0% +mechanics the local stress is going to + + + align:start position:0% +mechanics the local stress is going to +equal to some constant time the far away + + align:start position:0% +equal to some constant time the far away + + + align:start position:0% +equal to some constant time the far away +stress time the < TK of Pi a over the < + + align:start position:0% +stress time the < TK of Pi a over the < + + + align:start position:0% +stress time the < TK of Pi a over the < +TK of 2i R and that's at a distance R + + align:start position:0% +TK of 2i R and that's at a distance R + + + align:start position:0% +TK of 2i R and that's at a distance R +from ahead of the crack tip + + align:start position:0% + + + + align:start position:0% + +and if we look at our little schematic + + align:start position:0% +and if we look at our little schematic + + + align:start position:0% +and if we look at our little schematic +here we could say U it's hard to say + + align:start position:0% +here we could say U it's hard to say + + + align:start position:0% +here we could say U it's hard to say +exactly where the crack tip is but it + + align:start position:0% +exactly where the crack tip is but it + + + align:start position:0% +exactly where the crack tip is but it +would be somewhere in here and we'd say + + align:start position:0% +would be somewhere in here and we'd say + + + align:start position:0% +would be somewhere in here and we'd say +this next unbroken cell wall is a + + align:start position:0% +this next unbroken cell wall is a + + + align:start position:0% +this next unbroken cell wall is a +distance R ahead of the crack tip and + + align:start position:0% +distance R ahead of the crack tip and + + + align:start position:0% +distance R ahead of the crack tip and +that R is going to be related to L it's + + align:start position:0% +that R is going to be related to L it's + + + align:start position:0% +that R is going to be related to L it's +going to be some function of + + align:start position:0% +going to be some function of + + + align:start position:0% +going to be some function of +L so I can say the next unbroken wall + + align:start position:0% + + + + align:start position:0% + +ahead of the crack + + align:start position:0% + + + + align:start position:0% + +tip at some distance R that's going to + + align:start position:0% +tip at some distance R that's going to + + + align:start position:0% +tip at some distance R that's going to +be related to + + align:start position:0% +be related to + + + align:start position:0% +be related to +L and that's subject to a + + align:start position:0% + + + + align:start position:0% + +force which is going to be the local + + align:start position:0% +force which is going to be the local + + + align:start position:0% +force which is going to be the local +stress time l^ + + align:start position:0% + + + + align:start position:0% + +2 okay so that force is going to go as + + align:start position:0% +2 okay so that force is going to go as + + + align:start position:0% +2 okay so that force is going to go as +the local stress times l^2 and the local + + align:start position:0% +the local stress times l^2 and the local + + + align:start position:0% +the local stress times l^2 and the local +stress I can substitute this thing here + + align:start position:0% +stress I can substitute this thing here + + + align:start position:0% +stress I can substitute this thing here +in that's going to be proportional to + + align:start position:0% +in that's going to be proportional to + + + align:start position:0% +in that's going to be proportional to +the far away stress and now I'm going to + + align:start position:0% +the far away stress and now I'm going to + + + align:start position:0% +the far away stress and now I'm going to +get rid of the + + align:start position:0% +get rid of the + + + align:start position:0% +get rid of the +pies and I'm going to substitute for R + + align:start position:0% +pies and I'm going to substitute for R + + + align:start position:0% +pies and I'm going to substitute for R +I'm going to put in L so it's going to + + align:start position:0% +I'm going to put in L so it's going to + + + align:start position:0% +I'm going to put in L so it's going to +be proportional to the far away stress + + align:start position:0% +be proportional to the far away stress + + + align:start position:0% +be proportional to the far away stress +time the root of a over L and times l s + + align:start position:0% +time the root of a over L and times l s + + + align:start position:0% +time the root of a over L and times l s +there + + align:start position:0% + + + + align:start position:0% + +okay and then we're we're going to say + + align:start position:0% +okay and then we're we're going to say + + + align:start position:0% +okay and then we're we're going to say +again the edges are going to fail when + + align:start position:0% +again the edges are going to fail when + + + align:start position:0% +again the edges are going to fail when +the applied moment equals the fracture + + align:start position:0% +the applied moment equals the fracture + + + align:start position:0% +the applied moment equals the fracture +moment + + align:start position:0% + + + + align:start position:0% + +and the fracture moment is going to go + + align:start position:0% +and the fracture moment is going to go + + + align:start position:0% +and the fracture moment is going to go +as the modulus of rupture of the cell + + align:start position:0% +as the modulus of rupture of the cell + + + align:start position:0% +as the modulus of rupture of the cell +walls * T cubed and the applied moment + + align:start position:0% +walls * T cubed and the applied moment + + + align:start position:0% +walls * T cubed and the applied moment +is going to go as f * L and I've got F + + align:start position:0% +is going to go as f * L and I've got F + + + align:start position:0% +is going to go as f * L and I've got F +from up there so that goes as the far + + align:start position:0% +from up there so that goes as the far + + + align:start position:0% +from up there so that goes as the far +away stress Sigma infinite time the root + + align:start position:0% +away stress Sigma infinite time the root + + + align:start position:0% +away stress Sigma infinite time the root +of a over L and now I've got L Cub + + align:start position:0% +of a over L and now I've got L Cub + + + align:start position:0% +of a over L and now I've got L Cub +because there's an L squ there and + + align:start position:0% +because there's an L squ there and + + + align:start position:0% +because there's an L squ there and +there's an L down + + align:start position:0% + + + + align:start position:0% + +here and then if I just equate those + + align:start position:0% +here and then if I just equate those + + + align:start position:0% +here and then if I just equate those +then this is going to go as Sigma + + align:start position:0% +then this is going to go as Sigma + + + align:start position:0% +then this is going to go as Sigma +FS * T Cub like that so then I could say + + align:start position:0% +FS * T Cub like that so then I could say + + + align:start position:0% +FS * T Cub like that so then I could say +the fracture + + align:start position:0% +the fracture + + + align:start position:0% +the fracture +strength is equal to my far away stress + + align:start position:0% +strength is equal to my far away stress + + + align:start position:0% +strength is equal to my far away stress +that's going to go as my modulus of + + align:start position:0% +that's going to go as my modulus of + + + align:start position:0% +that's going to go as my modulus of +rupture time the root of L A * t + + align:start position:0% +rupture time the root of L A * t + + + align:start position:0% +rupture time the root of L A * t +l + + align:start position:0% +l + + + align:start position:0% +l +cubed and then my fracture toughness is + + align:start position:0% +cubed and then my fracture toughness is + + + align:start position:0% +cubed and then my fracture toughness is +going to be this tensile stress time the + + align:start position:0% +going to be this tensile stress time the + + + align:start position:0% +going to be this tensile stress time the +root of Pi + + align:start position:0% + + + + align:start position:0% + +a so there's going to be some other + + align:start position:0% +a so there's going to be some other + + + align:start position:0% +a so there's going to be some other +constant here which I'm going to call + + align:start position:0% +constant here which I'm going to call + + + align:start position:0% +constant here which I'm going to call +that + + align:start position:0% +that + + + align:start position:0% +that +C8 I've got the modulus of rupture of + + align:start position:0% +C8 I've got the modulus of rupture of + + + align:start position:0% +C8 I've got the modulus of rupture of +the + + align:start position:0% +the + + + align:start position:0% +the +solid I've got the square root of L and + + align:start position:0% +solid I've got the square root of L and + + + align:start position:0% +solid I've got the square root of L and +I'm just going to multiply by pi so it's + + align:start position:0% +I'm just going to multiply by pi so it's + + + align:start position:0% +I'm just going to multiply by pi so it's +like other fracture mechanics kinds of + + align:start position:0% + + + + align:start position:0% + +equations and then we multiply that + + align:start position:0% +equations and then we multiply that + + + align:start position:0% +equations and then we multiply that +times the relative density to the three + + align:start position:0% +times the relative density to the three + + + align:start position:0% +times the relative density to the three +Hales + + align:start position:0% + + + + align:start position:0% + +power and here if we look at + + align:start position:0% +power and here if we look at + + + align:start position:0% +power and here if we look at +data we find that that constant is about + + align:start position:0% +data we find that that constant is about + + + align:start position:0% +data we find that that constant is about +equal to 65 + + align:start position:0% + + + + align:start position:0% + +and here's another one of these plots so + + align:start position:0% +and here's another one of these plots so + + + align:start position:0% +and here's another one of these plots so +here I've I've normalized the fracture + + align:start position:0% +here I've I've normalized the fracture + + + align:start position:0% +here I've I've normalized the fracture +toughness of the Foams by the modulus of + + align:start position:0% +toughness of the Foams by the modulus of + + + align:start position:0% +toughness of the Foams by the modulus of +rupture of the cell walls times the root + + align:start position:0% +rupture of the cell walls times the root + + + align:start position:0% +rupture of the cell walls times the root +of Pi l so I've taken the cell size into + + align:start position:0% +of Pi l so I've taken the cell size into + + + align:start position:0% +of Pi l so I've taken the cell size into +account here and I've plotted against + + align:start position:0% +account here and I've plotted against + + + align:start position:0% +account here and I've plotted against +the relative density and that equation + + align:start position:0% +the relative density and that equation + + + align:start position:0% +the relative density and that equation +there is the same as this equation I've + + align:start position:0% +there is the same as this equation I've + + + align:start position:0% +there is the same as this equation I've +got down on the + + align:start position:0% + + + + align:start position:0% + +board and this is the only one of the + + align:start position:0% +board and this is the only one of the + + + align:start position:0% +board and this is the only one of the +properties that we've looked at that + + align:start position:0% +properties that we've looked at that + + + align:start position:0% +properties that we've looked at that +depends on the cell size right there's a + + align:start position:0% +depends on the cell size right there's a + + + align:start position:0% +depends on the cell size right there's a +cell size dependence here + + align:start position:0% + + + + align:start position:0% + +all right so I think that's all the + + align:start position:0% +all right so I think that's all the + + + align:start position:0% +all right so I think that's all the +modeling of the + + align:start position:0% + + + + align:start position:0% + +Foams are we + + align:start position:0% +Foams are we + + + align:start position:0% +Foams are we +good a lot of equations we're good okay + + align:start position:0% + + + + align:start position:0% + +Boop + + align:start position:0% + + + + align:start position:0% + +so I want to talk about how we might + + align:start position:0% +so I want to talk about how we might + + + align:start position:0% +so I want to talk about how we might +design Foams to improve their properties + + align:start position:0% +design Foams to improve their properties + + + align:start position:0% +design Foams to improve their properties +and then I wanted to talk about how we + + align:start position:0% +and then I wanted to talk about how we + + + align:start position:0% +and then I wanted to talk about how we +might select Foams for certain + + align:start position:0% +might select Foams for certain + + + align:start position:0% +might select Foams for certain +applications and look at Material + + align:start position:0% +applications and look at Material + + + align:start position:0% +applications and look at Material +selection charts so when we've been + + align:start position:0% +selection charts so when we've been + + + align:start position:0% +selection charts so when we've been +talking about the Foams especially the + + align:start position:0% +talking about the Foams especially the + + + align:start position:0% +talking about the Foams especially the +open cell foams we've been saying that + + align:start position:0% +open cell foams we've been saying that + + + align:start position:0% +open cell foams we've been saying that +their deformation is is largely by by + + align:start position:0% +their deformation is is largely by by + + + align:start position:0% +their deformation is is largely by by +bending of the cell edges and if we + + align:start position:0% +bending of the cell edges and if we + + + align:start position:0% +bending of the cell edges and if we +could do something to increase the + + align:start position:0% +could do something to increase the + + + align:start position:0% +could do something to increase the +stiffness of the edges or the strength + + align:start position:0% +stiffness of the edges or the strength + + + align:start position:0% +stiffness of the edges or the strength +of the edges then that would increase + + align:start position:0% +of the edges then that would increase + + + align:start position:0% +of the edges then that would increase +the overall properties of the foam and + + align:start position:0% +the overall properties of the foam and + + + align:start position:0% +the overall properties of the foam and +there's a couple of ways uh to think + + align:start position:0% +there's a couple of ways uh to think + + + align:start position:0% +there's a couple of ways uh to think +about doing that so the foam properties + + align:start position:0% +about doing that so the foam properties + + + align:start position:0% +about doing that so the foam properties +if if the foam is controlled by bending + + align:start position:0% +if if the foam is controlled by bending + + + align:start position:0% +if if the foam is controlled by bending +of the edges and the edges have some + + align:start position:0% +of the edges and the edges have some + + + align:start position:0% +of the edges and the edges have some +flexual rigidity EI if we could increase + + align:start position:0% +flexual rigidity EI if we could increase + + + align:start position:0% +flexual rigidity EI if we could increase +that EI of the edges we would increase + + align:start position:0% +that EI of the edges we would increase + + + align:start position:0% +that EI of the edges we would increase +the properties of the foam and one way + + align:start position:0% +the properties of the foam and one way + + + align:start position:0% +the properties of the foam and one way +to do that is by making the this the + + align:start position:0% +to do that is by making the this the + + + align:start position:0% +to do that is by making the this the +edges Hollow so if we had Hollow edges + + align:start position:0% +edges Hollow so if we had Hollow edges + + + align:start position:0% +edges Hollow so if we had Hollow edges +and you had a tube then that would + + align:start position:0% +and you had a tube then that would + + + align:start position:0% +and you had a tube then that would +increase the EI and I'll I'll we can + + align:start position:0% +increase the EI and I'll I'll we can + + + align:start position:0% +increase the EI and I'll I'll we can +work out sort of how much it's going to + + align:start position:0% +work out sort of how much it's going to + + + align:start position:0% +work out sort of how much it's going to +increase them and I have a little + + align:start position:0% +increase them and I have a little + + + align:start position:0% +increase them and I have a little +example here of ah wrong thing sorry I + + align:start position:0% +example here of ah wrong thing sorry I + + + align:start position:0% +example here of ah wrong thing sorry I +have a little example of a natural + + align:start position:0% +have a little example of a natural + + + align:start position:0% +have a little example of a natural +example of hollow foam + + align:start position:0% + + + + align:start position:0% + +struts so this is a a grass I don't know + + align:start position:0% +struts so this is a a grass I don't know + + + align:start position:0% +struts so this is a a grass I don't know +what kind of grass it is I just saw this + + align:start position:0% +what kind of grass it is I just saw this + + + align:start position:0% +what kind of grass it is I just saw this +grass and we picked some different + + align:start position:0% +grass and we picked some different + + + align:start position:0% +grass and we picked some different +grasses and we took some sem pictures + + align:start position:0% +grasses and we took some sem pictures + + + align:start position:0% +grasses and we took some sem pictures +and uh it has a really kind of common + + align:start position:0% +and uh it has a really kind of common + + + align:start position:0% +and uh it has a really kind of common +structure for a grass it's very common + + align:start position:0% +structure for a grass it's very common + + + align:start position:0% +structure for a grass it's very common +for grass stems to have sort of a solid + + align:start position:0% +for grass stems to have sort of a solid + + + align:start position:0% +for grass stems to have sort of a solid +uh outer part and then a foamlike inner + + align:start position:0% +uh outer part and then a foamlike inner + + + align:start position:0% +uh outer part and then a foamlike inner +part it's so common that botanists have + + align:start position:0% +part it's so common that botanists have + + + align:start position:0% +part it's so common that botanists have +a name for it they're called the Corine + + align:start position:0% +a name for it they're called the Corine + + + align:start position:0% +a name for it they're called the Corine +structure and if you take one of these + + align:start position:0% +structure and if you take one of these + + + align:start position:0% +structure and if you take one of these +um grass stems and you look at the sort + + align:start position:0% +um grass stems and you look at the sort + + + align:start position:0% +um grass stems and you look at the sort +of foamy bit in the middle and you uh do + + align:start position:0% +of foamy bit in the middle and you uh do + + + align:start position:0% +of foamy bit in the middle and you uh do +a you know sem picture of that you can + + align:start position:0% +a you know sem picture of that you can + + + align:start position:0% +a you know sem picture of that you can +see that the little cell walls are + + align:start position:0% +see that the little cell walls are + + + align:start position:0% +see that the little cell walls are +actually little Hollow tubes so if you + + align:start position:0% +actually little Hollow tubes so if you + + + align:start position:0% +actually little Hollow tubes so if you +know each one of these things is a + + align:start position:0% +know each one of these things is a + + + align:start position:0% +know each one of these things is a +little Hollow tube so what I wanted to + + align:start position:0% +little Hollow tube so what I wanted to + + + align:start position:0% +little Hollow tube so what I wanted to +do is work out how much the uh say + + align:start position:0% +do is work out how much the uh say + + + align:start position:0% +do is work out how much the uh say +modulus of the foam would increase if + + align:start position:0% +modulus of the foam would increase if + + + align:start position:0% +modulus of the foam would increase if +you could make all the edges into little + + align:start position:0% +you could make all the edges into little + + + align:start position:0% +you could make all the edges into little +hollow + + align:start position:0% +hollow + + + align:start position:0% +hollow +tubes so we're going to start by saying + + align:start position:0% +tubes so we're going to start by saying + + + align:start position:0% +tubes so we're going to start by saying +the foam behavior is dominated by cell + + align:start position:0% +the foam behavior is dominated by cell + + + align:start position:0% +the foam behavior is dominated by cell +bending C Edge bending + + align:start position:0% + + + + align:start position:0% + +and the foam properties can be increased + + align:start position:0% +and the foam properties can be increased + + + align:start position:0% +and the foam properties can be increased +by increasing the EI of the cell + + align:start position:0% + + + + align:start position:0% + +wall so there's a couple ways we could + + align:start position:0% +wall so there's a couple ways we could + + + align:start position:0% +wall so there's a couple ways we could +do that so the first one is looking at + + align:start position:0% +do that so the first one is looking at + + + align:start position:0% +do that so the first one is looking at +hollow wall + + align:start position:0% + + + + align:start position:0% + +so imagine I have a thin wall tube just + + align:start position:0% +so imagine I have a thin wall tube just + + + align:start position:0% +so imagine I have a thin wall tube just +a circular thin wall + + align:start position:0% + + + + align:start position:0% + +tube there's my little wall there it has + + align:start position:0% +tube there's my little wall there it has + + + align:start position:0% +tube there's my little wall there it has +some radius little r and a wall + + align:start position:0% +some radius little r and a wall + + + align:start position:0% +some radius little r and a wall +thickness + + align:start position:0% +thickness + + + align:start position:0% +thickness +T and then imagine I have the same + + align:start position:0% +T and then imagine I have the same + + + align:start position:0% +T and then imagine I have the same +amount of mass but now I have a solid + + align:start position:0% +amount of mass but now I have a solid + + + align:start position:0% +amount of mass but now I have a solid +Circ cular + + align:start position:0% +Circ cular + + + align:start position:0% +Circ cular +section and I'm going to say the radius + + align:start position:0% +section and I'm going to say the radius + + + align:start position:0% +section and I'm going to say the radius +of that is Big + + align:start position:0% + + + + align:start position:0% + +R okay so for our thin wall + + align:start position:0% + + + + align:start position:0% + +tube the moment of inertia is pi R cubed + + align:start position:0% +tube the moment of inertia is pi R cubed + + + align:start position:0% +tube the moment of inertia is pi R cubed +times the thickness T if it's thin and + + align:start position:0% +times the thickness T if it's thin and + + + align:start position:0% +times the thickness T if it's thin and +for our solid circular section + + align:start position:0% + + + + align:start position:0% + +I is going to be Pi Big R to 4th over + + align:start position:0% +I is going to be Pi Big R to 4th over + + + align:start position:0% +I is going to be Pi Big R to 4th over +4 and if I say I want to set this up so + + align:start position:0% +4 and if I say I want to set this up so + + + align:start position:0% +4 and if I say I want to set this up so +that the masses are equal then the areas + + align:start position:0% +that the masses are equal then the areas + + + align:start position:0% +that the masses are equal then the areas +of the cross-sections have to be equal + + align:start position:0% +of the cross-sections have to be equal + + + align:start position:0% +of the cross-sections have to be equal +say it's from the same + + align:start position:0% + + + + align:start position:0% + +material so the masses are going to be + + align:start position:0% +material so the masses are going to be + + + align:start position:0% +material so the masses are going to be +equal if P Pi Big R 2 is equal to 2 pi + + align:start position:0% +equal if P Pi Big R 2 is equal to 2 pi + + + align:start position:0% +equal if P Pi Big R 2 is equal to 2 pi +little r + + align:start position:0% +little r + + + align:start position:0% +little r +t so I'm going to solve here for R so + + align:start position:0% +t so I'm going to solve here for R so + + + align:start position:0% +t so I'm going to solve here for R so +the pi are going to cancel out so the + + align:start position:0% +the pi are going to cancel out so the + + + align:start position:0% +the pi are going to cancel out so the +masses are equal if Big R is equal to + + align:start position:0% +masses are equal if Big R is equal to + + + align:start position:0% +masses are equal if Big R is equal to +theare < TK of 2 * little r * + + align:start position:0% + + + + align:start position:0% + +T and then what we're going to do is see + + align:start position:0% +T and then what we're going to do is see + + + align:start position:0% +T and then what we're going to do is see +how big is the moment of inertia of the + + align:start position:0% +how big is the moment of inertia of the + + + align:start position:0% +how big is the moment of inertia of the +tube relative to the solid so the tube + + align:start position:0% +tube relative to the solid so the tube + + + align:start position:0% +tube relative to the solid so the tube +was Pi little r Cub T and the solid was + + align:start position:0% +was Pi little r Cub T and the solid was + + + align:start position:0% +was Pi little r Cub T and the solid was +Pi Big R 4th / 4 and I'm going to get + + align:start position:0% +Pi Big R 4th / 4 and I'm going to get + + + align:start position:0% +Pi Big R 4th / 4 and I'm going to get +get rid of the Big R here I can get rid + + align:start position:0% +get rid of the Big R here I can get rid + + + align:start position:0% +get rid of the Big R here I can get rid +of the pies + + align:start position:0% + + + + align:start position:0% + +there so R to the 4th is going to be 4 + + align:start position:0% +there so R to the 4th is going to be 4 + + + align:start position:0% +there so R to the 4th is going to be 4 +r^ 2 t^ + + align:start position:0% +r^ 2 t^ + + + align:start position:0% +r^ 2 t^ +2 so the fours are going to go and this + + align:start position:0% +2 so the fours are going to go and this + + + align:start position:0% +2 so the fours are going to go and this +boils down to + + align:start position:0% + + + + align:start position:0% + +R/T so if I had a thin wall + + align:start position:0% +R/T so if I had a thin wall + + + align:start position:0% +R/T so if I had a thin wall +tube the moment of inertia is going to + + align:start position:0% +tube the moment of inertia is going to + + + align:start position:0% +tube the moment of inertia is going to +be r/ T bigger than if I had the same + + align:start position:0% +be r/ T bigger than if I had the same + + + align:start position:0% +be r/ T bigger than if I had the same +mass in a solid circular section + + align:start position:0% +mass in a solid circular section + + + align:start position:0% +mass in a solid circular section +so you can see for the little plant here + + align:start position:0% +so you can see for the little plant here + + + align:start position:0% +so you can see for the little plant here +by making a thin wall tube you're + + align:start position:0% +by making a thin wall tube you're + + + align:start position:0% +by making a thin wall tube you're +increasing the stiffness of the foam + + align:start position:0% +increasing the stiffness of the foam + + + align:start position:0% +increasing the stiffness of the foam +with the same amount of material okay + + align:start position:0% +with the same amount of material okay + + + align:start position:0% +with the same amount of material okay +that's the + + align:start position:0% +that's the + + + align:start position:0% +that's the +idea and you can do a similar kind of + + align:start position:0% +idea and you can do a similar kind of + + + align:start position:0% +idea and you can do a similar kind of +analysis for other + + align:start position:0% + + + + align:start position:0% + +properties so that's if we have hollow + + align:start position:0% +properties so that's if we have hollow + + + align:start position:0% +properties so that's if we have hollow +tubes so another option is we could have + + align:start position:0% +tubes so another option is we could have + + + align:start position:0% +tubes so another option is we could have +cell walls that are sandwich structures + + align:start position:0% +cell walls that are sandwich structures + + + align:start position:0% +cell walls that are sandwich structures +so imagine if the cell walls themselves + + align:start position:0% +so imagine if the cell walls themselves + + + align:start position:0% +so imagine if the cell walls themselves +were little tiny sandwich structures + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% + + + + align:start position:0% + +so when you have a sandwich + + align:start position:0% + + + + align:start position:0% + +beam what you have is two stiff strong + + align:start position:0% +beam what you have is two stiff strong + + + align:start position:0% +beam what you have is two stiff strong +faces that are separated by some sort of + + align:start position:0% +faces that are separated by some sort of + + + align:start position:0% +faces that are separated by some sort of +porous core like a honeycomb or a foam + + align:start position:0% +porous core like a honeycomb or a foam + + + align:start position:0% +porous core like a honeycomb or a foam +or bals of wood and the idea + + align:start position:0% +or bals of wood and the idea + + + align:start position:0% +or bals of wood and the idea +with the sandwich structure if I draw a + + align:start position:0% +with the sandwich structure if I draw a + + + align:start position:0% +with the sandwich structure if I draw a +little sort of sketch of the + + align:start position:0% + + + + align:start position:0% + +sandwich there's my faces so imagine + + align:start position:0% +sandwich there's my faces so imagine + + + align:start position:0% +sandwich there's my faces so imagine +those are solid so they might be + + align:start position:0% +those are solid so they might be + + + align:start position:0% +those are solid so they might be +aluminum sheets or they might be fiber + + align:start position:0% +aluminum sheets or they might be fiber + + + align:start position:0% +aluminum sheets or they might be fiber +reinforced Composites and then we have + + align:start position:0% +reinforced Composites and then we have + + + align:start position:0% +reinforced Composites and then we have +some sort of cellular thing + + align:start position:0% +some sort of cellular thing + + + align:start position:0% +some sort of cellular thing +here is the core and the idea is that's + + align:start position:0% +here is the core and the idea is that's + + + align:start position:0% +here is the core and the idea is that's +analogous to an I + + align:start position:0% +analogous to an I + + + align:start position:0% +analogous to an I +beam so in the sandwich beam we have two + + align:start position:0% + + + + align:start position:0% + +stiff strong + + align:start position:0% + + + + align:start position:0% + +faces separated by a lightweight + + align:start position:0% + + + + align:start position:0% + +core so the core is typically a + + align:start position:0% +core so the core is typically a + + + align:start position:0% +core so the core is typically a +honeycomb or a + + align:start position:0% +honeycomb or a + + + align:start position:0% +honeycomb or a +foam or Bala + + align:start position:0% + + + + align:start position:0% + +wood and the idea is you increase the + + align:start position:0% +wood and the idea is you increase the + + + align:start position:0% +wood and the idea is you increase the +moment of inertia of the cross-section + + align:start position:0% +moment of inertia of the cross-section + + + align:start position:0% +moment of inertia of the cross-section +with little increase in + + align:start position:0% + + + + align:start position:0% + +weight and if you think of an ibeam an + + align:start position:0% +weight and if you think of an ibeam an + + + align:start position:0% +weight and if you think of an ibeam an +ibeam has a large moment of inertia + + align:start position:0% +ibeam has a large moment of inertia + + + align:start position:0% +ibeam has a large moment of inertia +because you're separating the flanges by + + align:start position:0% +because you're separating the flanges by + + + align:start position:0% +because you're separating the flanges by +the web and the sandwich beam works in + + align:start position:0% +the web and the sandwich beam works in + + + align:start position:0% +the web and the sandwich beam works in +the same way you're separating the Faces + + align:start position:0% +the same way you're separating the Faces + + + align:start position:0% +the same way you're separating the Faces +by the core but the core doesn't weigh + + align:start position:0% +by the core but the core doesn't weigh + + + align:start position:0% +by the core but the core doesn't weigh +very much because it's a cellular + + align:start position:0% +very much because it's a cellular + + + align:start position:0% +very much because it's a cellular +thing so the faces of the sandwich are + + align:start position:0% +thing so the faces of the sandwich are + + + align:start position:0% +thing so the faces of the sandwich are +like the flanges in the + + align:start position:0% + + + + align:start position:0% + +ibeam and then the core is like the + + align:start position:0% + + + + align:start position:0% + +web okay so the idea is to make + + align:start position:0% +web okay so the idea is to make + + + align:start position:0% +web okay so the idea is to make +something called a micro sandwich foam + + align:start position:0% + + + + align:start position:0% + +so what you want to do is make the cell + + align:start position:0% +so what you want to do is make the cell + + + align:start position:0% +so what you want to do is make the cell +walls into sandwiches and one way to do + + align:start position:0% +walls into sandwiches and one way to do + + + align:start position:0% +walls into sandwiches and one way to do +that is to disperse a large volume + + align:start position:0% +that is to disperse a large volume + + + align:start position:0% +that is to disperse a large volume +fraction of thin walled spheres into the + + align:start position:0% + + + + align:start position:0% + +foam um and you have to get the geometry + + align:start position:0% +foam um and you have to get the geometry + + + align:start position:0% +foam um and you have to get the geometry +geometry right to make it work so let me + + align:start position:0% +geometry right to make it work so let me + + + align:start position:0% +geometry right to make it work so let me +draw a little kind of sketch here for + + align:start position:0% +draw a little kind of sketch here for + + + align:start position:0% +draw a little kind of sketch here for +how it + + align:start position:0% +how it + + + align:start position:0% +how it +works so here's our thin walled + + align:start position:0% + + + + align:start position:0% + +spheres and then you're going to + + align:start position:0% +spheres and then you're going to + + + align:start position:0% +spheres and then you're going to +distribute those in a foam so here's + + align:start position:0% +distribute those in a foam so here's + + + align:start position:0% +distribute those in a foam so here's +another sphere over here spheres are not + + align:start position:0% + + + + align:start position:0% + +perfect let's say there was another one + + align:start position:0% +perfect let's say there was another one + + + align:start position:0% +perfect let's say there was another one +in here + + align:start position:0% + + + + align:start position:0% + +and then the idea is this stuff in here + + align:start position:0% +and then the idea is this stuff in here + + + align:start position:0% +and then the idea is this stuff in here +would be the + + align:start position:0% + + + + align:start position:0% + +foam so these guys are Hollow + + align:start position:0% + + + + align:start position:0% + +spheres and say the Spheres have a + + align:start position:0% +spheres and say the Spheres have a + + + align:start position:0% +spheres and say the Spheres have a +diameter + + align:start position:0% +diameter + + + align:start position:0% +diameter +D and say they have a wall thickness + + align:start position:0% +D and say they have a wall thickness + + + align:start position:0% +D and say they have a wall thickness +here of T and say this the separation of + + align:start position:0% +here of T and say this the separation of + + + align:start position:0% +here of T and say this the separation of +the Spheres I'm going to call C + + align:start position:0% +the Spheres I'm going to call C + + + align:start position:0% +the Spheres I'm going to call C +if you can see that there and then the + + align:start position:0% +if you can see that there and then the + + + align:start position:0% +if you can see that there and then the +cell size of the + + align:start position:0% +cell size of the + + + align:start position:0% +cell size of the +foam I'm going to call Little + + align:start position:0% + + + + align:start position:0% + +D so there's a bunch of parameters you + + align:start position:0% +D so there's a bunch of parameters you + + + align:start position:0% +D so there's a bunch of parameters you +have to kind of play with to get this to + + align:start position:0% + + + + align:start position:0% + +work so you have to have thin walled + + align:start position:0% +work so you have to have thin walled + + + align:start position:0% +work so you have to have thin walled +spheres so that the faces are thin the + + align:start position:0% +spheres so that the faces are thin the + + + align:start position:0% +spheres so that the faces are thin the +sandwich panels work best when the faces + + align:start position:0% +sandwich panels work best when the faces + + + align:start position:0% +sandwich panels work best when the faces +are thin so you need the thickness of + + align:start position:0% +are thin so you need the thickness of + + + align:start position:0% +are thin so you need the thickness of +the sphere to be much less than D you + + align:start position:0% +the sphere to be much less than D you + + + align:start position:0% +the sphere to be much less than D you +you need the faces to be stiff relative + + align:start position:0% +you need the faces to be stiff relative + + + align:start position:0% +you need the faces to be stiff relative +to the foam so you need the modulus of + + align:start position:0% +to the foam so you need the modulus of + + + align:start position:0% +to the foam so you need the modulus of +the sphere material to be greater than + + align:start position:0% +the sphere material to be greater than + + + align:start position:0% +the sphere material to be greater than +the modulus of the + + align:start position:0% + + + + align:start position:0% + +foam and you need the volume fraction of + + align:start position:0% +foam and you need the volume fraction of + + + align:start position:0% +foam and you need the volume fraction of +the Spheres to be relatively High to get + + align:start position:0% +the Spheres to be relatively High to get + + + align:start position:0% +the Spheres to be relatively High to get +the Spheres close enough together for + + align:start position:0% +the Spheres close enough together for + + + align:start position:0% +the Spheres close enough together for +this to work so you want that volume + + align:start position:0% +this to work so you want that volume + + + align:start position:0% +this to work so you want that volume +fraction to be something like 50 to + + align:start position:0% +fraction to be something like 50 to + + + align:start position:0% +fraction to be something like 50 to +60% and for the foam you need to have + + align:start position:0% +60% and for the foam you need to have + + + align:start position:0% +60% and for the foam you need to have +the foam cell size less than the + + align:start position:0% +the foam cell size less than the + + + align:start position:0% +the foam cell size less than the +separation between the Spheres you need + + align:start position:0% +separation between the Spheres you need + + + align:start position:0% +separation between the Spheres you need +to have a number of you can't just have + + align:start position:0% +to have a number of you can't just have + + + align:start position:0% +to have a number of you can't just have +one pore in here it's not really like a + + align:start position:0% +one pore in here it's not really like a + + + align:start position:0% +one pore in here it's not really like a +foam you can't it won't behave like a + + align:start position:0% +foam you can't it won't behave like a + + + align:start position:0% +foam you can't it won't behave like a +foam as a Continuum so you need to have + + align:start position:0% +foam as a Continuum so you need to have + + + align:start position:0% +foam as a Continuum so you need to have +a number of different cell sizes in + + align:start position:0% +a number of different cell sizes in + + + align:start position:0% +a number of different cell sizes in +between each um between each sphere and + + align:start position:0% +between each um between each sphere and + + + align:start position:0% +between each um between each sphere and +so you need the cell size of the foam to + + align:start position:0% +so you need the cell size of the foam to + + + align:start position:0% +so you need the cell size of the foam to +be a lot less than the separation of the + + align:start position:0% +be a lot less than the separation of the + + + align:start position:0% +be a lot less than the separation of the +Spheres there C but if you can control + + align:start position:0% +Spheres there C but if you can control + + + align:start position:0% +Spheres there C but if you can control +this geometry you can get this sandwich + + align:start position:0% +this geometry you can get this sandwich + + + align:start position:0% +this geometry you can get this sandwich +effect and you can get uh improved + + align:start position:0% +effect and you can get uh improved + + + align:start position:0% +effect and you can get uh improved +Properties by doing that so there's ways + + align:start position:0% +Properties by doing that so there's ways + + + align:start position:0% +Properties by doing that so there's ways +you can play around with the structure + + align:start position:0% +you can play around with the structure + + + align:start position:0% +you can play around with the structure +of the Foams to improve their + + align:start position:0% +of the Foams to improve their + + + align:start position:0% +of the Foams to improve their +properties so that was one thing I + + align:start position:0% +properties so that was one thing I + + + align:start position:0% +properties so that was one thing I +wanted to say + + align:start position:0% + + + + align:start position:0% + +another way to improve the properties of + + align:start position:0% +another way to improve the properties of + + + align:start position:0% +another way to improve the properties of +a of a foam like material is to use one + + align:start position:0% +a of a foam like material is to use one + + + align:start position:0% +a of a foam like material is to use one +of those lattice materials so you know + + align:start position:0% +of those lattice materials so you know + + + align:start position:0% +of those lattice materials so you know +we've been talking about ways to improve + + align:start position:0% +we've been talking about ways to improve + + + align:start position:0% +we've been talking about ways to improve +the bending stiffness but if you could + + align:start position:0% +the bending stiffness but if you could + + + align:start position:0% +the bending stiffness but if you could +get rid of the bending all together and + + align:start position:0% +get rid of the bending all together and + + + align:start position:0% +get rid of the bending all together and +have axial deformation in the cell walls + + align:start position:0% +have axial deformation in the cell walls + + + align:start position:0% +have axial deformation in the cell walls +then it would be much stiffer and you + + align:start position:0% +then it would be much stiffer and you + + + align:start position:0% +then it would be much stiffer and you +can get axial deformation by having + + align:start position:0% +can get axial deformation by having + + + align:start position:0% +can get axial deformation by having +those uh 3D truss kind of materials so I + + align:start position:0% +those uh 3D truss kind of materials so I + + + align:start position:0% +those uh 3D truss kind of materials so I +just I think I have a picture of oops + + align:start position:0% +just I think I have a picture of oops + + + align:start position:0% +just I think I have a picture of oops +there we go so there's one of those 3D + + align:start position:0% +there we go so there's one of those 3D + + + align:start position:0% +there we go so there's one of those 3D +Trust materials so another alternative + + align:start position:0% +Trust materials so another alternative + + + align:start position:0% +Trust materials so another alternative +is to sort of get rid of the bending all + + align:start position:0% +is to sort of get rid of the bending all + + + align:start position:0% +is to sort of get rid of the bending all +together and to try to make a trust type + + align:start position:0% +together and to try to make a trust type + + + align:start position:0% +together and to try to make a trust type +material + + align:start position:0% + + + + align:start position:0% + +so there's various ways to make these I + + align:start position:0% +so there's various ways to make these I + + + align:start position:0% +so there's various ways to make these I +think we talked about a few of them + + align:start position:0% +think we talked about a few of them + + + align:start position:0% +think we talked about a few of them +earlier on and you can analyze them as + + align:start position:0% +earlier on and you can analyze them as + + + align:start position:0% +earlier on and you can analyze them as +as trust type structures and I can just + + align:start position:0% +as trust type structures and I can just + + + align:start position:0% +as trust type structures and I can just +run through a sort of little dimensional + + align:start position:0% +run through a sort of little dimensional + + + align:start position:0% +run through a sort of little dimensional +argument to get the modulus so the + + align:start position:0% +argument to get the modulus so the + + + align:start position:0% +argument to get the modulus so the +modulus is going to go as the stress + + align:start position:0% +modulus is going to go as the stress + + + align:start position:0% +modulus is going to go as the stress +over the strain the stress is going to + + align:start position:0% +over the strain the stress is going to + + + align:start position:0% +over the strain the stress is going to +go as a force over a length squared The + + align:start position:0% +go as a force over a length squared The + + + align:start position:0% +go as a force over a length squared The +Strain is going to go as a deformation + + align:start position:0% +Strain is going to go as a deformation + + + align:start position:0% +Strain is going to go as a deformation +over l so this is just like what we had + + align:start position:0% +over l so this is just like what we had + + + align:start position:0% +over l so this is just like what we had +before for the Foams but in this case + + align:start position:0% +before for the Foams but in this case + + + align:start position:0% +before for the Foams but in this case +the deformation is going to go as the + + align:start position:0% +the deformation is going to go as the + + + align:start position:0% +the deformation is going to go as the +force times the length over the area of + + align:start position:0% +force times the length over the area of + + + align:start position:0% +force times the length over the area of +the + + align:start position:0% +the + + + align:start position:0% +the +cross-section uh divided by es + + align:start position:0% +cross-section uh divided by es + + + align:start position:0% +cross-section uh divided by es +s uh because we're pulling it or pushing + + align:start position:0% +s uh because we're pulling it or pushing + + + align:start position:0% +s uh because we're pulling it or pushing +it ax and so that goes as FL L over t^2 + + align:start position:0% +it ax and so that goes as FL L over t^2 + + + align:start position:0% +it ax and so that goes as FL L over t^2 +es + + align:start position:0% +es + + + align:start position:0% +es +s and if I just put that back in the + + align:start position:0% +s and if I just put that back in the + + + align:start position:0% +s and if I just put that back in the +equation here for the modulus I get + + align:start position:0% +equation here for the modulus I get + + + align:start position:0% +equation here for the modulus I get +we've got F over L and then I've got + + align:start position:0% +we've got F over L and then I've got + + + align:start position:0% +we've got F over L and then I've got +Delta here so that's f l t^2 + + align:start position:0% +Delta here so that's f l t^2 + + + align:start position:0% +Delta here so that's f l t^2 +DS and you just get the modulus goes + + align:start position:0% +DS and you just get the modulus goes + + + align:start position:0% +DS and you just get the modulus goes +as the modulus of the solid time T l^ + + align:start position:0% +as the modulus of the solid time T l^ + + + align:start position:0% +as the modulus of the solid time T l^ +2 and that goes as the modulus of the + + align:start position:0% +2 and that goes as the modulus of the + + + align:start position:0% +2 and that goes as the modulus of the +solid + + align:start position:0% +solid + + + align:start position:0% +solid +times the relative density so for the + + align:start position:0% +times the relative density so for the + + + align:start position:0% +times the relative density so for the +open cell Foams the modulus went as the + + align:start position:0% +open cell Foams the modulus went as the + + + align:start position:0% +open cell Foams the modulus went as the +relative density squared so if it was + + align:start position:0% +relative density squared so if it was + + + align:start position:0% +relative density squared so if it was +10% solid the modulus would be 0.01 and + + align:start position:0% +10% solid the modulus would be 0.01 and + + + align:start position:0% +10% solid the modulus would be 0.01 and +this is saying if it's 10% solid the + + align:start position:0% +this is saying if it's 10% solid the + + + align:start position:0% +this is saying if it's 10% solid the +modulus is 0.1 so it's much bigger right + + align:start position:0% +modulus is 0.1 so it's much bigger right + + + align:start position:0% +modulus is 0.1 so it's much bigger right +so this is all sort of well and good uh + + align:start position:0% +so this is all sort of well and good uh + + + align:start position:0% +so this is all sort of well and good uh +the only difficulty is that uh in when + + align:start position:0% +the only difficulty is that uh in when + + + align:start position:0% +the only difficulty is that uh in when +you when you look at the modulus you can + + align:start position:0% +you when you look at the modulus you can + + + align:start position:0% +you when you look at the modulus you can +do reasonably well but when you look at + + align:start position:0% +do reasonably well but when you look at + + + align:start position:0% +do reasonably well but when you look at +the strength some of the members are + + align:start position:0% +the strength some of the members are + + + align:start position:0% +the strength some of the members are +going to be inevitably in compression + + align:start position:0% +going to be inevitably in compression + + + align:start position:0% +going to be inevitably in compression +when you have these trust materials some + + align:start position:0% +when you have these trust materials some + + + align:start position:0% +when you have these trust materials some +members are going to be in tension some + + align:start position:0% +members are going to be in tension some + + + align:start position:0% +members are going to be in tension some +members are going to be in compression + + align:start position:0% +members are going to be in compression + + + align:start position:0% +members are going to be in compression +and the compression members tend to + + align:start position:0% +and the compression members tend to + + + align:start position:0% +and the compression members tend to +buckle and once the compression members + + align:start position:0% +buckle and once the compression members + + + align:start position:0% +buckle and once the compression members +Buckle then you're back to the same kind + + align:start position:0% +Buckle then you're back to the same kind + + + align:start position:0% +Buckle then you're back to the same kind +of strength relationship that you have + + align:start position:0% +of strength relationship that you have + + + align:start position:0% +of strength relationship that you have +for the foam so that's um one of the + + align:start position:0% +for the foam so that's um one of the + + + align:start position:0% +for the foam so that's um one of the +difficulties of + + align:start position:0% +difficulties of + + + align:start position:0% +difficulties of +this so let me say that the + + align:start position:0% +this so let me say that the + + + align:start position:0% +this so let me say that the +strength so if the if it the strength + + align:start position:0% +strength so if the if it the strength + + + align:start position:0% +strength so if the if it the strength +failed if the strength was controlled by + + align:start position:0% +failed if the strength was controlled by + + + align:start position:0% +failed if the strength was controlled by +uni aial yield it would go linearly with + + align:start position:0% +uni aial yield it would go linearly with + + + align:start position:0% +uni aial yield it would go linearly with +relative density but if it goes as + + align:start position:0% +relative density but if it goes as + + + align:start position:0% +relative density but if it goes as +buckling it goes as the square + + align:start position:0% + + + + align:start position:0% + +so I'll just say the compression members + + align:start position:0% +so I'll just say the compression members + + + align:start position:0% +so I'll just say the compression members +can can buckle + + align:start position:0% + + + + align:start position:0% + +and say you had a + + align:start position:0% +and say you had a + + + align:start position:0% +and say you had a +metal um + + align:start position:0% +metal um + + + align:start position:0% +metal um +lattice then there's some interaction + + align:start position:0% +lattice then there's some interaction + + + align:start position:0% +lattice then there's some interaction +between the plastic Behavior and the + + align:start position:0% +between the plastic Behavior and the + + + align:start position:0% +between the plastic Behavior and the +buckling and you use What's called the + + align:start position:0% +buckling and you use What's called the + + + align:start position:0% +buckling and you use What's called the +tangent modulus instead of just the + + align:start position:0% +tangent modulus instead of just the + + + align:start position:0% +tangent modulus instead of just the +young modulus and the tangent meas + + align:start position:0% +young modulus and the tangent meas + + + align:start position:0% +young modulus and the tangent meas +modulus is lower and there's also what's + + align:start position:0% +modulus is lower and there's also what's + + + align:start position:0% +modulus is lower and there's also what's +called knockdown factors that can be + + align:start position:0% +called knockdown factors that can be + + + align:start position:0% +called knockdown factors that can be +large too + + align:start position:0% + + + + align:start position:0% + +so the knockdown Factor can be like + + align:start position:0% + + + + align:start position:0% + +50% so that the measured strength can be + + align:start position:0% +50% so that the measured strength can be + + + align:start position:0% +50% so that the measured strength can be +half of what you thought it was going to + + align:start position:0% +half of what you thought it was going to + + + align:start position:0% +half of what you thought it was going to +be so oops this should be a squared over + + align:start position:0% +be so oops this should be a squared over + + + align:start position:0% +be so oops this should be a squared over +here Sor + + align:start position:0% +here Sor + + + align:start position:0% +here Sor +right so that even though the the + + align:start position:0% +right so that even though the the + + + align:start position:0% +right so that even though the the +stiffness of these 3D trusses can be + + align:start position:0% +stiffness of these 3D trusses can be + + + align:start position:0% +stiffness of these 3D trusses can be +quite good uh the strength often isn't + + align:start position:0% +quite good uh the strength often isn't + + + align:start position:0% +quite good uh the strength often isn't +quite as good as one might hope so so + + align:start position:0% +quite as good as one might hope so so + + + align:start position:0% +quite as good as one might hope so so +that's one of the issues with + + align:start position:0% +that's one of the issues with + + + align:start position:0% +that's one of the issues with +them all + + align:start position:0% + + + + align:start position:0% + +right so do you see the idea though with + + align:start position:0% +right so do you see the idea though with + + + align:start position:0% +right so do you see the idea though with +all these different um micro structures + + align:start position:0% +all these different um micro structures + + + align:start position:0% +all these different um micro structures +is that you can control the structure in + + align:start position:0% +is that you can control the structure in + + + align:start position:0% +is that you can control the structure in +a way to try to increase the bending + + align:start position:0% +a way to try to increase the bending + + + align:start position:0% +a way to try to increase the bending +stiffness or get rid of the bending + + align:start position:0% +stiffness or get rid of the bending + + + align:start position:0% +stiffness or get rid of the bending +stiffness and increase the axial + + align:start position:0% +stiffness and increase the axial + + + align:start position:0% +stiffness and increase the axial +stiffness so there's things you can do + + align:start position:0% +stiffness so there's things you can do + + + align:start position:0% +stiffness so there's things you can do +to play around with that + + align:start position:0% + + + + align:start position:0% + +okay and I wanted to talk a bit today + + align:start position:0% +okay and I wanted to talk a bit today + + + align:start position:0% +okay and I wanted to talk a bit today +about material selection charts for + + align:start position:0% +about material selection charts for + + + align:start position:0% +about material selection charts for +Foams so when we talked about Woods we + + align:start position:0% +Foams so when we talked about Woods we + + + align:start position:0% +Foams so when we talked about Woods we +started talking about this remember I + + align:start position:0% +started talking about this remember I + + + align:start position:0% +started talking about this remember I +derived a little performance index we + + align:start position:0% +derived a little performance index we + + + align:start position:0% +derived a little performance index we +said if we had a a material and we + + align:start position:0% +said if we had a a material and we + + + align:start position:0% +said if we had a a material and we +wanted to have a given stiffness and we + + align:start position:0% +wanted to have a given stiffness and we + + + align:start position:0% +wanted to have a given stiffness and we +wanted to minimize the mass we had that + + align:start position:0% +wanted to minimize the mass we had that + + + align:start position:0% +wanted to minimize the mass we had that +performance index that was e to the 1/2 + + align:start position:0% +performance index that was e to the 1/2 + + + align:start position:0% +performance index that was e to the 1/2 +over row and we had a chart of modulus + + align:start position:0% +over row and we had a chart of modulus + + + align:start position:0% +over row and we had a chart of modulus +versus density and we saw that wood was + + align:start position:0% +versus density and we saw that wood was + + + align:start position:0% +versus density and we saw that wood was +really good you can do that for other + + align:start position:0% +really good you can do that for other + + + align:start position:0% +really good you can do that for other +sorts of properties not just modulus so + + align:start position:0% +sorts of properties not just modulus so + + + align:start position:0% +sorts of properties not just modulus so +you can you can make a a u depending on + + align:start position:0% +you can you can make a a u depending on + + + align:start position:0% +you can you can make a a u depending on +what the mechanical requirement is you + + align:start position:0% +what the mechanical requirement is you + + + align:start position:0% +what the mechanical requirement is you +can work out different performance + + align:start position:0% +can work out different performance + + + align:start position:0% +can work out different performance +indices so I wanted to go into that in a + + align:start position:0% +indices so I wanted to go into that in a + + + align:start position:0% +indices so I wanted to go into that in a +little bit more detail so so the + + align:start position:0% +little bit more detail so so the + + + align:start position:0% +little bit more detail so so the +question is how do we select the best + + align:start position:0% +question is how do we select the best + + + align:start position:0% +question is how do we select the best +material for some + + align:start position:0% +material for some + + + align:start position:0% +material for some +mechanical uh requirement + + align:start position:0% + + + + align:start position:0% + +so in the wood section we looked at the + + align:start position:0% +so in the wood section we looked at the + + + align:start position:0% +so in the wood section we looked at the +minimum mass of a beam of a given + + align:start position:0% + + + + align:start position:0% + +stiffness and we saw that the + + align:start position:0% +stiffness and we saw that the + + + align:start position:0% +stiffness and we saw that the +performance index was e to the2 over + + align:start position:0% +performance index was e to the2 over + + + align:start position:0% +performance index was e to the2 over +row so let me let me do another one of + + align:start position:0% +row so let me let me do another one of + + + align:start position:0% +row so let me let me do another one of +these little examples and then I'll show + + align:start position:0% +these little examples and then I'll show + + + align:start position:0% +these little examples and then I'll show +you some more of them so another example + + align:start position:0% +you some more of them so another example + + + align:start position:0% +you some more of them so another example +would be what material uh minimize the + + align:start position:0% +would be what material uh minimize the + + + align:start position:0% +would be what material uh minimize the +mass of of a beam of a given strength or + + align:start position:0% +mass of of a beam of a given strength or + + + align:start position:0% +mass of of a beam of a given strength or +given failure + + align:start position:0% + + + + align:start position:0% + +load so I'll call the failure load PF + + align:start position:0% +load so I'll call the failure load PF + + + align:start position:0% +load so I'll call the failure load PF +and we can say the maximum stress in the + + align:start position:0% +and we can say the maximum stress in the + + + align:start position:0% +and we can say the maximum stress in the +beam is going to be the moment in the + + align:start position:0% +beam is going to be the moment in the + + + align:start position:0% +beam is going to be the moment in the +beam times the distance from the neutral + + align:start position:0% +beam times the distance from the neutral + + + align:start position:0% +beam times the distance from the neutral +axis Y and divided by the moment of + + align:start position:0% +axis Y and divided by the moment of + + + align:start position:0% +axis Y and divided by the moment of +inertia so here m is the maximum moment + + align:start position:0% +inertia so here m is the maximum moment + + + align:start position:0% +inertia so here m is the maximum moment +in the + + align:start position:0% + + + + align:start position:0% + +beam and Y is the maximum distance from + + align:start position:0% +beam and Y is the maximum distance from + + + align:start position:0% +beam and Y is the maximum distance from +the neutral axis + + align:start position:0% + + + + align:start position:0% + +and I is the moment of inertia and I'm + + align:start position:0% +and I is the moment of inertia and I'm + + + align:start position:0% +and I is the moment of inertia and I'm +going to um say I goes as T 4th and I'm + + align:start position:0% +going to um say I goes as T 4th and I'm + + + align:start position:0% +going to um say I goes as T 4th and I'm +going to define a failure stress of the + + align:start position:0% +going to define a failure stress of the + + + align:start position:0% +going to define a failure stress of the +material Sigma + + align:start position:0% + + + + align:start position:0% + +F so Sigma + + align:start position:0% +F so Sigma + + + align:start position:0% +F so Sigma +Max is going to go as my failure load + + align:start position:0% +Max is going to go as my failure load + + + align:start position:0% +Max is going to go as my failure load +times the length that would be the + + align:start position:0% +times the length that would be the + + + align:start position:0% +times the length that would be the +moment the distance from the neutral + + align:start position:0% +moment the distance from the neutral + + + align:start position:0% +moment the distance from the neutral +axis is going to go as T and the moment + + align:start position:0% +axis is going to go as T and the moment + + + align:start position:0% +axis is going to go as T and the moment +of inertia is going to go as T + + align:start position:0% + + + + align:start position:0% + +4th and that's going to be the failure + + align:start position:0% +4th and that's going to be the failure + + + align:start position:0% +4th and that's going to be the failure +strength there so I can solve this for T + + align:start position:0% +strength there so I can solve this for T + + + align:start position:0% +strength there so I can solve this for T +and then I'm going to write the mass in + + align:start position:0% +and then I'm going to write the mass in + + + align:start position:0% +and then I'm going to write the mass in +terms of T and put that in there so here + + align:start position:0% +terms of T and put that in there so here + + + align:start position:0% +terms of T and put that in there so here +T goes + + align:start position:0% +T goes + + + align:start position:0% +T goes +as let's see p + + align:start position:0% +as let's see p + + + align:start position:0% +as let's see p +f Lo L / Sigma F and that's going to be + + align:start position:0% +f Lo L / Sigma F and that's going to be + + + align:start position:0% +f Lo L / Sigma F and that's going to be +to the 13 + + align:start position:0% + + + + align:start position:0% + +power let's see I guess I could scoot + + align:start position:0% +power let's see I guess I could scoot + + + align:start position:0% +power let's see I guess I could scoot +over here + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% + + + + align:start position:0% + +and we could say that the mass + + align:start position:0% +and we could say that the mass + + + align:start position:0% +and we could say that the mass +m goes as the density * T ^2 * + + align:start position:0% +m goes as the density * T ^2 * + + + align:start position:0% +m goes as the density * T ^2 * +l so the mass m is going to go as row * + + align:start position:0% +l so the mass m is going to go as row * + + + align:start position:0% +l so the mass m is going to go as row * +L * T + + align:start position:0% + + + + align:start position:0% + +cubed t^ squ + + align:start position:0% +cubed t^ squ + + + align:start position:0% +cubed t^ squ +rather so that whole thing goes to the + + align:start position:0% +rather so that whole thing goes to the + + + align:start position:0% +rather so that whole thing goes to the +2/3 + + align:start position:0% +2/3 + + + align:start position:0% +2/3 +power so if we look at the material + + align:start position:0% +power so if we look at the material + + + align:start position:0% +power so if we look at the material +properties the Mass goes as the density + + align:start position:0% +properties the Mass goes as the density + + + align:start position:0% +properties the Mass goes as the density +time the failure + + align:start position:0% +time the failure + + + align:start position:0% +time the failure +stress raised to the 2/3 power so if we + + align:start position:0% +stress raised to the 2/3 power so if we + + + align:start position:0% +stress raised to the 2/3 power so if we +want to minimize the mass we want to + + align:start position:0% +want to minimize the mass we want to + + + align:start position:0% +want to minimize the mass we want to +minimize row over Sigma F to the 2/3 or + + align:start position:0% +minimize row over Sigma F to the 2/3 or + + + align:start position:0% +minimize row over Sigma F to the 2/3 or +we want to maximize Sigma F to the 2/3 + + align:start position:0% +we want to maximize Sigma F to the 2/3 + + + align:start position:0% +we want to maximize Sigma F to the 2/3 +over + + align:start position:0% + + + + align:start position:0% + +row so that's the performance index for + + align:start position:0% +row so that's the performance index for + + + align:start position:0% +row so that's the performance index for +that case + + align:start position:0% + + + + align:start position:0% + +okay so we can obtain these performance + + align:start position:0% +okay so we can obtain these performance + + + align:start position:0% +okay so we can obtain these performance +indices for different loading + + align:start position:0% +indices for different loading + + + align:start position:0% +indices for different loading +configurations and different mechanical + + align:start position:0% +configurations and different mechanical + + + align:start position:0% +configurations and different mechanical +requirements and I don't want to go + + align:start position:0% +requirements and I don't want to go + + + align:start position:0% +requirements and I don't want to go +through a whole lot of them but I'm + + align:start position:0% +through a whole lot of them but I'm + + + align:start position:0% +through a whole lot of them but I'm +going to put this up with the notes so + + align:start position:0% +going to put this up with the notes so + + + align:start position:0% +going to put this up with the notes so +this is from Mike Ashby's book on + + align:start position:0% +this is from Mike Ashby's book on + + + align:start position:0% +this is from Mike Ashby's book on +material selection and mechanical design + + align:start position:0% +material selection and mechanical design + + + align:start position:0% +material selection and mechanical design +and this is a whole series of these + + align:start position:0% +and this is a whole series of these + + + align:start position:0% +and this is a whole series of these +performance indices for different + + align:start position:0% +performance indices for different + + + align:start position:0% +performance indices for different +situations for things loaded in torsion + + align:start position:0% +situations for things loaded in torsion + + + align:start position:0% +situations for things loaded in torsion +for columns and buckling for panels and + + align:start position:0% +for columns and buckling for panels and + + + align:start position:0% +for columns and buckling for panels and +bending uh so these ones are all for + + align:start position:0% +bending uh so these ones are all for + + + align:start position:0% +bending uh so these ones are all for +stiffness and they're all involve a + + align:start position:0% +stiffness and they're all involve a + + + align:start position:0% +stiffness and they're all involve a +modulus raised to some power divided by + + align:start position:0% +modulus raised to some power divided by + + + align:start position:0% +modulus raised to some power divided by +a density so a tie in tension it's e + + align:start position:0% +a density so a tie in tension it's e + + + align:start position:0% +a density so a tie in tension it's e +over row uh the beam in bending is e to + + align:start position:0% +over row uh the beam in bending is e to + + + align:start position:0% +over row uh the beam in bending is e to +the one half over row a plate and + + align:start position:0% +the one half over row a plate and + + + align:start position:0% +the one half over row a plate and +bending is e to 1/3 over row so you + + align:start position:0% +bending is e to 1/3 over row so you + + + align:start position:0% +bending is e to 1/3 over row so you +don't need to memorize those but you can + + align:start position:0% +don't need to memorize those but you can + + + align:start position:0% +don't need to memorize those but you can +see you can derive these for different + + align:start position:0% +see you can derive these for different + + + align:start position:0% +see you can derive these for different +situations and here's another one for + + align:start position:0% +situations and here's another one for + + + align:start position:0% +situations and here's another one for +strength limited design so the shaft is + + align:start position:0% +strength limited design so the shaft is + + + align:start position:0% +strength limited design so the shaft is +uh you know depending on what the + + align:start position:0% +uh you know depending on what the + + + align:start position:0% +uh you know depending on what the +specifications are it's a strength + + align:start position:0% +specifications are it's a strength + + + align:start position:0% +specifications are it's a strength +raised to the 2/3 power over row the + + align:start position:0% +raised to the 2/3 power over row the + + + align:start position:0% +raised to the 2/3 power over row the +beam loaded and bending the top one + + align:start position:0% +beam loaded and bending the top one + + + align:start position:0% +beam loaded and bending the top one +there Sigma F to the the 2/3 over row + + align:start position:0% +there Sigma F to the the 2/3 over row + + + align:start position:0% +there Sigma F to the the 2/3 over row +that's what we just did so there's all + + align:start position:0% +that's what we just did so there's all + + + align:start position:0% +that's what we just did so there's all +these different kind of performance + + align:start position:0% +these different kind of performance + + + align:start position:0% +these different kind of performance +indices so depending on what your + + align:start position:0% +indices so depending on what your + + + align:start position:0% +indices so depending on what your +situation is you would pick one of these + + align:start position:0% +situation is you would pick one of these + + + align:start position:0% +situation is you would pick one of these +indices and then what you can do is use + + align:start position:0% +indices and then what you can do is use + + + align:start position:0% +indices and then what you can do is use +these material selection charts which + + align:start position:0% +these material selection charts which + + + align:start position:0% +these material selection charts which +plot one property against another on log + + align:start position:0% +plot one property against another on log + + + align:start position:0% +plot one property against another on log +log scales and because all of these + + align:start position:0% +log scales and because all of these + + + align:start position:0% +log scales and because all of these +performance indices involve a power they + + align:start position:0% +performance indices involve a power they + + + align:start position:0% +performance indices involve a power they +always end up being a straight line on + + align:start position:0% +always end up being a straight line on + + + align:start position:0% +always end up being a straight line on +your log log plot and here this one I + + align:start position:0% +your log log plot and here this one I + + + align:start position:0% +your log log plot and here this one I +think is the same as what I showed you + + align:start position:0% +think is the same as what I showed you + + + align:start position:0% +think is the same as what I showed you +for the for the wood this one's the + + align:start position:0% +for the for the wood this one's the + + + align:start position:0% +for the for the wood this one's the +modulus here plotted against + + align:start position:0% +modulus here plotted against + + + align:start position:0% +modulus here plotted against +so Foams are down here and there's you + + align:start position:0% +so Foams are down here and there's you + + + align:start position:0% +so Foams are down here and there's you +know other engineering materials are + + align:start position:0% +know other engineering materials are + + + align:start position:0% +know other engineering materials are +over + + align:start position:0% + + + + align:start position:0% + +here and these guidelines here are the + + align:start position:0% +here and these guidelines here are the + + + align:start position:0% +here and these guidelines here are the +different performance indices so this + + align:start position:0% +different performance indices so this + + + align:start position:0% +different performance indices so this +one's e over row this one's e to the 1/2 + + align:start position:0% +one's e over row this one's e to the 1/2 + + + align:start position:0% +one's e over row this one's e to the 1/2 +over row this one's e to the 1/3 over + + align:start position:0% +over row this one's e to the 1/3 over + + + align:start position:0% +over row this one's e to the 1/3 over +row and for this case here is you move + + align:start position:0% +row and for this case here is you move + + + align:start position:0% +row and for this case here is you move +the lines up to the top leftand Corner + + align:start position:0% +the lines up to the top leftand Corner + + + align:start position:0% +the lines up to the top leftand Corner +E's getting bigger row is getting + + align:start position:0% +E's getting bigger row is getting + + + align:start position:0% +E's getting bigger row is getting +smaller and so the actual value of the + + align:start position:0% +smaller and so the actual value of the + + + align:start position:0% +smaller and so the actual value of the +performance index is getting bigger okay + + align:start position:0% +performance index is getting bigger okay + + + align:start position:0% +performance index is getting bigger okay +so you can use this to select the + + align:start position:0% +so you can use this to select the + + + align:start position:0% +so you can use this to select the +material so we've made these charts for + + align:start position:0% +material so we've made these charts for + + + align:start position:0% +material so we've made these charts for +Foams as well + + align:start position:0% +Foams as well + + + align:start position:0% +Foams as well +so here's a couple of charts for Foams + + align:start position:0% +so here's a couple of charts for Foams + + + align:start position:0% +so here's a couple of charts for Foams +and I think what I'm going to do is just + + align:start position:0% +and I think what I'm going to do is just + + + align:start position:0% +and I think what I'm going to do is just +go through them quickly and there aren't + + align:start position:0% +go through them quickly and there aren't + + + align:start position:0% +go through them quickly and there aren't +really that many notes I'll just put the + + align:start position:0% +really that many notes I'll just put the + + + align:start position:0% +really that many notes I'll just put the +notes on the website and you can I won't + + align:start position:0% +notes on the website and you can I won't + + + align:start position:0% +notes on the website and you can I won't +write all the notes down um and then we + + align:start position:0% +write all the notes down um and then we + + + align:start position:0% +write all the notes down um and then we +can finish this today um so this one + + align:start position:0% +can finish this today um so this one + + + align:start position:0% +can finish this today um so this one +here is the Young's modulus versus + + align:start position:0% +here is the Young's modulus versus + + + align:start position:0% +here is the Young's modulus versus +density and these are all sorts of + + align:start position:0% +density and these are all sorts of + + + align:start position:0% +density and these are all sorts of +different Foams so the low modulus ones + + align:start position:0% +different Foams so the low modulus ones + + + align:start position:0% +different Foams so the low modulus ones +tend to be flexible the higher modulus + + align:start position:0% +tend to be flexible the higher modulus + + + align:start position:0% +tend to be flexible the higher modulus +ones tend to be more rigid and you could + + align:start position:0% +ones tend to be more rigid and you could + + + align:start position:0% +ones tend to be more rigid and you could +use this to um select Foams if you + + align:start position:0% +use this to um select Foams if you + + + align:start position:0% +use this to um select Foams if you +wanted um you can also see what the + + align:start position:0% +wanted um you can also see what the + + + align:start position:0% +wanted um you can also see what the +range of values is so the values of the + + align:start position:0% +range of values is so the values of the + + + align:start position:0% +range of values is so the values of the +of the modulus here goes from uh a + + align:start position:0% +of the modulus here goes from uh a + + + align:start position:0% +of the modulus here goes from uh a +little less than 100 um because these + + align:start position:0% +little less than 100 um because these + + + align:start position:0% +little less than 100 um because these +this is two orders of magnitude here I + + align:start position:0% +this is two orders of magnitude here I + + + align:start position:0% +this is two orders of magnitude here I +think each one of these uh down to about + + align:start position:0% +think each one of these uh down to about + + + align:start position:0% +think each one of these uh down to about +10 Theus 4 a little less than that so + + align:start position:0% +10 Theus 4 a little less than that so + + + align:start position:0% +10 Theus 4 a little less than that so +there's a huge range there's almost a + + align:start position:0% +there's a huge range there's almost a + + + align:start position:0% +there's a huge range there's almost a +range of a factor of a million in those + + align:start position:0% +range of a factor of a million in those + + + align:start position:0% +range of a factor of a million in those +uh moduli and the same with the strength + + align:start position:0% +uh moduli and the same with the strength + + + align:start position:0% +uh moduli and the same with the strength +here the strengths go from uh 10us 3 + + align:start position:0% +here the strengths go from uh 10us 3 + + + align:start position:0% +here the strengths go from uh 10us 3 +megapascals up to about maybe 30 megap + + align:start position:0% +megapascals up to about maybe 30 megap + + + align:start position:0% +megapascals up to about maybe 30 megap +pascals something like that and you can + + align:start position:0% +pascals something like that and you can + + + align:start position:0% +pascals something like that and you can +see for the modul and the strength + + align:start position:0% +see for the modul and the strength + + + align:start position:0% +see for the modul and the strength +things like the metal Foams are good the + + align:start position:0% +things like the metal Foams are good the + + + align:start position:0% +things like the metal Foams are good the +bals is good here's the BSA up here + + align:start position:0% +bals is good here's the BSA up here + + + align:start position:0% +bals is good here's the BSA up here +metal Foams up there so you can kind of + + align:start position:0% +metal Foams up there so you can kind of + + + align:start position:0% +metal Foams up there so you can kind of +see the range + + align:start position:0% +see the range + + + align:start position:0% +see the range +of the range of properties that you + + align:start position:0% +of the range of properties that you + + + align:start position:0% +of the range of properties that you +could + + align:start position:0% +could + + + align:start position:0% +could +get and then you can + + align:start position:0% +get and then you can + + + align:start position:0% +get and then you can +also I need to drink hang + + align:start position:0% + + + + align:start position:0% + +on you can also plot the specific + + align:start position:0% +on you can also plot the specific + + + align:start position:0% +on you can also plot the specific +properties so here's the compressive + + align:start position:0% +properties so here's the compressive + + + align:start position:0% +properties so here's the compressive +strength of divided by the density + + align:start position:0% +strength of divided by the density + + + align:start position:0% +strength of divided by the density +plotted against the Young's modulus + + align:start position:0% +plotted against the Young's modulus + + + align:start position:0% +plotted against the Young's modulus +divided by the density and here you want + + align:start position:0% +divided by the density and here you want + + + align:start position:0% +divided by the density and here you want +to be up at this end so you would have a + + align:start position:0% +to be up at this end so you would have a + + + align:start position:0% +to be up at this end so you would have a +high strength and a high stiffness so + + align:start position:0% +high strength and a high stiffness so + + + align:start position:0% +high strength and a high stiffness so +the Balsa and the metal Foams are good + + align:start position:0% +the Balsa and the metal Foams are good + + + align:start position:0% +the Balsa and the metal Foams are good +up here uh this next plot this is the + + align:start position:0% +up here uh this next plot this is the + + + align:start position:0% +up here uh this next plot this is the +compressive stress at 25% strain and + + align:start position:0% +compressive stress at 25% strain and + + + align:start position:0% +compressive stress at 25% strain and +this is the densification strain and if + + align:start position:0% +this is the densification strain and if + + + align:start position:0% +this is the densification strain and if +you think of + + align:start position:0% +you think of + + + align:start position:0% +you think of +having um you know your stress strain + + align:start position:0% +having um you know your stress strain + + + align:start position:0% +having um you know your stress strain +curve looks like + + align:start position:0% +curve looks like + + + align:start position:0% +curve looks like +this something like that so you could + + align:start position:0% +this something like that so you could + + + align:start position:0% +this something like that so you could +say that's + + align:start position:0% +say that's + + + align:start position:0% +say that's +a strain of 0.25 and that's the stress + + align:start position:0% +a strain of 0.25 and that's the stress + + + align:start position:0% +a strain of 0.25 and that's the stress +that corresponds to that so that stress + + align:start position:0% +that corresponds to that so that stress + + + align:start position:0% +that corresponds to that so that stress +times The densification Strain which is + + align:start position:0% +times The densification Strain which is + + + align:start position:0% +times The densification Strain which is +out here some place is an estimate of + + align:start position:0% +out here some place is an estimate of + + + align:start position:0% +out here some place is an estimate of +the energy underneath the stress strain + + align:start position:0% +the energy underneath the stress strain + + + align:start position:0% +the energy underneath the stress strain +curve so you can think of this right + + align:start position:0% +curve so you can think of this right + + + align:start position:0% +curve so you can think of this right +hand plot here those dashed lines these + + align:start position:0% +hand plot here those dashed lines these + + + align:start position:0% +hand plot here those dashed lines these +lines like this and this and this each + + align:start position:0% +lines like this and this and this each + + + align:start position:0% +lines like this and this and this each +one of those corresponds to how much + + align:start position:0% +one of those corresponds to how much + + + align:start position:0% +one of those corresponds to how much +energy you would absorb under the stress + + align:start position:0% +energy you would absorb under the stress + + + align:start position:0% +energy you would absorb under the stress +strain curve so here's uh you know + + align:start position:0% +strain curve so here's uh you know + + + align:start position:0% +strain curve so here's uh you know +points that lie on here would have an + + align:start position:0% +points that lie on here would have an + + + align:start position:0% +points that lie on here would have an +energy of 0.001 Mega per cubic meter and + + align:start position:0% +energy of 0.001 Mega per cubic meter and + + + align:start position:0% +energy of 0.001 Mega per cubic meter and +over here we're at 10 Jew per cubic + + align:start position:0% +over here we're at 10 Jew per cubic + + + align:start position:0% +over here we're at 10 Jew per cubic +meter so again the Bala and the metal + + align:start position:0% +meter so again the Bala and the metal + + + align:start position:0% +meter so again the Bala and the metal +Foams are are good over here so you can + + align:start position:0% +Foams are are good over here so you can + + + align:start position:0% +Foams are are good over here so you can +use these plots to try to identify Foams + + align:start position:0% +use these plots to try to identify Foams + + + align:start position:0% +use these plots to try to identify Foams +for particular + + align:start position:0% +for particular + + + align:start position:0% +for particular +applications and I think there's a + + align:start position:0% +applications and I think there's a + + + align:start position:0% +applications and I think there's a +couple more doesn't have to be + + align:start position:0% +couple more doesn't have to be + + + align:start position:0% +couple more doesn't have to be +mechanical properties here's thermal + + align:start position:0% +mechanical properties here's thermal + + + align:start position:0% +mechanical properties here's thermal +conductivity versus compressive strength + + align:start position:0% +conductivity versus compressive strength + + + align:start position:0% +conductivity versus compressive strength +so you could imagine if you wanted some + + align:start position:0% +so you could imagine if you wanted some + + + align:start position:0% +so you could imagine if you wanted some +insulation you want to have a certain + + align:start position:0% +insulation you want to have a certain + + + align:start position:0% +insulation you want to have a certain +thermal conductivity value you probably + + align:start position:0% +thermal conductivity value you probably + + + align:start position:0% +thermal conductivity value you probably +also need at least some minimal + + align:start position:0% +also need at least some minimal + + + align:start position:0% +also need at least some minimal +compressive strength uh you could also + + align:start position:0% +compressive strength uh you could also + + + align:start position:0% +compressive strength uh you could also +have something like a maximum service + + align:start position:0% +have something like a maximum service + + + align:start position:0% +have something like a maximum service +temperature that you know maybe the + + align:start position:0% +temperature that you know maybe the + + + align:start position:0% +temperature that you know maybe the +foam's going to melt at some temperature + + align:start position:0% +foam's going to melt at some temperature + + + align:start position:0% +foam's going to melt at some temperature +you can't go beyond that so uh so + + align:start position:0% +you can't go beyond that so uh so + + + align:start position:0% +you can't go beyond that so uh so +there's some property there and I think + + align:start position:0% +there's some property there and I think + + + align:start position:0% +there's some property there and I think +I think there's one more here um you can + + align:start position:0% +I think there's one more here um you can + + + align:start position:0% +I think there's one more here um you can +look at things like the density in terms + + align:start position:0% +look at things like the density in terms + + + align:start position:0% +look at things like the density in terms +of the buoyancy of the foam if you had + + align:start position:0% +of the buoyancy of the foam if you had + + + align:start position:0% +of the buoyancy of the foam if you had +some buoyancy application and you can + + align:start position:0% +some buoyancy application and you can + + + align:start position:0% +some buoyancy application and you can +look at cell size on this one here uh + + align:start position:0% +look at cell size on this one here uh + + + align:start position:0% +look at cell size on this one here uh +and cell size can be important for + + align:start position:0% +and cell size can be important for + + + align:start position:0% +and cell size can be important for +things like filtration and catalysis so + + align:start position:0% +things like filtration and catalysis so + + + align:start position:0% +things like filtration and catalysis so +the amount of surface area goes as one + + align:start position:0% +the amount of surface area goes as one + + + align:start position:0% +the amount of surface area goes as one +over the cell size the surface area per + + align:start position:0% +over the cell size the surface area per + + + align:start position:0% +over the cell size the surface area per +unit volume and so the cell size can be + + align:start position:0% +unit volume and so the cell size can be + + + align:start position:0% +unit volume and so the cell size can be +important for those sorts of + + align:start position:0% +important for those sorts of + + + align:start position:0% +important for those sorts of +applications so the idea is you can make + + align:start position:0% +applications so the idea is you can make + + + align:start position:0% +applications so the idea is you can make +these material selection charts for foam + + align:start position:0% +these material selection charts for foam + + + align:start position:0% +these material selection charts for foam +and you can put data on there and you + + align:start position:0% +and you can put data on there and you + + + align:start position:0% +and you can put data on there and you +can compare Foams and you can use these + + align:start position:0% +can compare Foams and you can use these + + + align:start position:0% +can compare Foams and you can use these +performance indices okay so I'm going to + + align:start position:0% +performance indices okay so I'm going to + + + align:start position:0% +performance indices okay so I'm going to +leave it at that there were there's a + + align:start position:0% +leave it at that there were there's a + + + align:start position:0% +leave it at that there were there's a +little bit more notes but I'll just put + + align:start position:0% +little bit more notes but I'll just put + + + align:start position:0% +little bit more notes but I'll just put +them on the website and you can you can + + align:start position:0% +them on the website and you can you can + + + align:start position:0% +them on the website and you can you can +get them from there okay so I think + + align:start position:0% +get them from there okay so I think + + + align:start position:0% +get them from there okay so I think +we're good for today \ No newline at end of file diff --git a/WtOJN2TCD6o.txt b/WtOJN2TCD6o.txt new file mode 100644 index 0000000000000000000000000000000000000000..e32df320ad60161b575f540ee3af9a16664dd6e4 --- /dev/null +++ b/WtOJN2TCD6o.txt @@ -0,0 +1,13131 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT open courseware continue + + align:start position:0% +will help MIT open courseware continue + + + align:start position:0% +will help MIT open courseware continue +to offer highquality educational + + align:start position:0% +to offer highquality educational + + + align:start position:0% +to offer highquality educational +resources for free to make a donation or + + align:start position:0% +resources for free to make a donation or + + + align:start position:0% +resources for free to make a donation or +view additional materials from hundreds + + align:start position:0% +view additional materials from hundreds + + + align:start position:0% +view additional materials from hundreds +of MIT courses visit MIT opencourseware + + align:start position:0% +of MIT courses visit MIT opencourseware + + + align:start position:0% +of MIT courses visit MIT opencourseware +at + + align:start position:0% + + + + align:start position:0% + +ocw.mit.edu all right so where were we + + align:start position:0% +ocw.mit.edu all right so where were we + + + align:start position:0% +ocw.mit.edu all right so where were we +last time so we would had derived the + + align:start position:0% +last time so we would had derived the + + + align:start position:0% +last time so we would had derived the +fir on Lin which is at the top of the + + align:start position:0% +fir on Lin which is at the top of the + + + align:start position:0% +fir on Lin which is at the top of the +board and the really the only difference + + align:start position:0% +board and the really the only difference + + + align:start position:0% +board and the really the only difference +between this and what we talked about + + align:start position:0% +between this and what we talked about + + + align:start position:0% +between this and what we talked about +earlier is that we had performed the + + align:start position:0% +earlier is that we had performed the + + + align:start position:0% +earlier is that we had performed the +multiple expansion so we distinguished + + align:start position:0% +multiple expansion so we distinguished + + + align:start position:0% +multiple expansion so we distinguished +between cinear moment momenta that are + + align:start position:0% +between cinear moment momenta that are + + + align:start position:0% +between cinear moment momenta that are +scaling like a cinear momentum and + + align:start position:0% +scaling like a cinear momentum and + + + align:start position:0% +scaling like a cinear momentum and +momentum that are scaling like an Ultras + + align:start position:0% +momentum that are scaling like an Ultras + + + align:start position:0% +momentum that are scaling like an Ultras +soft and only the cinear pieces were + + align:start position:0% +soft and only the cinear pieces were + + + align:start position:0% +soft and only the cinear pieces were +showing up in here and same with the + + align:start position:0% +showing up in here and same with the + + + align:start position:0% +showing up in here and same with the +clinar gauge field it was only showing + + align:start position:0% +clinar gauge field it was only showing + + + align:start position:0% +clinar gauge field it was only showing +up in here whereas both were showing up + + align:start position:0% +up in here whereas both were showing up + + + align:start position:0% +up in here whereas both were showing up +in + + align:start position:0% +in + + + align:start position:0% +in +here there's only a single type of + + align:start position:0% +here there's only a single type of + + + align:start position:0% +here there's only a single type of +derivative here because ultr soft and + + align:start position:0% +derivative here because ultr soft and + + + align:start position:0% +derivative here because ultr soft and +cinear momentum are the same size in the + + align:start position:0% +cinear momentum are the same size in the + + + align:start position:0% +cinear momentum are the same size in the +N component but they're different in + + align:start position:0% +N component but they're different in + + + align:start position:0% +N component but they're different in +these other components so we had to we + + align:start position:0% +these other components so we had to we + + + align:start position:0% +these other components so we had to we +had these labels and this label operator + + align:start position:0% +had these labels and this label operator + + + align:start position:0% +had these labels and this label operator +that picked out the cinear momenta so we + + align:start position:0% +that picked out the cinear momenta so we + + + align:start position:0% +that picked out the cinear momenta so we +could Define cinear coant derivatives if + + align:start position:0% +could Define cinear coant derivatives if + + + align:start position:0% +could Define cinear coant derivatives if +you like with this subscript n whereas + + align:start position:0% +you like with this subscript n whereas + + + align:start position:0% +you like with this subscript n whereas +this D is kind of like a full derivative + + align:start position:0% +this D is kind of like a full derivative + + + align:start position:0% +this D is kind of like a full derivative +that involves both types of gauge field + + align:start position:0% +that involves both types of gauge field + + + align:start position:0% +that involves both types of gauge field +and then at the end of lecture it was + + align:start position:0% +and then at the end of lecture it was + + + align:start position:0% +and then at the end of lecture it was +kind of rush but I was talking about the + + align:start position:0% +kind of rush but I was talking about the + + + align:start position:0% +kind of rush but I was talking about the +colar gluon lrange and I said there's a + + align:start position:0% +colar gluon lrange and I said there's a + + + align:start position:0% +colar gluon lrange and I said there's a +set of replacement rules that we could + + align:start position:0% +set of replacement rules that we could + + + align:start position:0% +set of replacement rules that we could +make to effectively do the same thing + + align:start position:0% +make to effectively do the same thing + + + align:start position:0% +make to effectively do the same thing +that we did here and now I've just + + align:start position:0% +that we did here and now I've just + + + align:start position:0% +that we did here and now I've just +written out for you what that lran is + + align:start position:0% +written out for you what that lran is + + + align:start position:0% +written out for you what that lran is +with those replacement rules so curly D + + align:start position:0% +with those replacement rules so curly D + + + align:start position:0% +with those replacement rules so curly D +is is basically just taking all the + + align:start position:0% +is is basically just taking all the + + + align:start position:0% +is is basically just taking all the +derivatives and taking only the leading + + align:start position:0% +derivatives and taking only the leading + + + align:start position:0% +derivatives and taking only the leading +order pieces so we take the colinear + + align:start position:0% +order pieces so we take the colinear + + + align:start position:0% +order pieces so we take the colinear +pieces and the this component and this + + align:start position:0% +pieces and the this component and this + + + align:start position:0% +pieces and the this component and this +component we take the ultrasoft pieces + + align:start position:0% +component we take the ultrasoft pieces + + + align:start position:0% +component we take the ultrasoft pieces +in this component and then if you wrote + + align:start position:0% +in this component and then if you wrote + + + align:start position:0% +in this component and then if you wrote +the original lran as a commutator of two + + align:start position:0% +the original lran as a commutator of two + + + align:start position:0% +the original lran as a commutator of two +Co variant derivatives you just replace + + align:start position:0% +Co variant derivatives you just replace + + + align:start position:0% +Co variant derivatives you just replace +it by the leading order pieces and + + align:start position:0% +it by the leading order pieces and + + + align:start position:0% +it by the leading order pieces and +that's what the leading order action + + align:start position:0% +that's what the leading order action + + + align:start position:0% +that's what the leading order action +will be then we had to think about gauge + + align:start position:0% +will be then we had to think about gauge + + + align:start position:0% +will be then we had to think about gauge +fixing since this is the cinear gluon + + align:start position:0% +fixing since this is the cinear gluon + + + align:start position:0% +fixing since this is the cinear gluon +lran we should think about cinear gauge + + align:start position:0% +lran we should think about cinear gauge + + + align:start position:0% +lran we should think about cinear gauge +fixing this here is a general covariant + + align:start position:0% +fixing this here is a general covariant + + + align:start position:0% +fixing this here is a general covariant +gauge fixing the with parameter Tow and + + align:start position:0% +gauge fixing the with parameter Tow and + + + align:start position:0% +gauge fixing the with parameter Tow and +then there's a corresponding ghost term + + align:start position:0% +then there's a corresponding ghost term + + + align:start position:0% +then there's a corresponding ghost term +and in this lran the usual way it would + + align:start position:0% +and in this lran the usual way it would + + + align:start position:0% +and in this lran the usual way it would +look this would + + align:start position:0% +look this would + + + align:start position:0% +look this would +be I + + align:start position:0% +be I + + + align:start position:0% +be I +partial and then I said that because we + + align:start position:0% +partial and then I said that because we + + + align:start position:0% +partial and then I said that because we +don't want the colinear gauge fixing + + align:start position:0% +don't want the colinear gauge fixing + + + align:start position:0% +don't want the colinear gauge fixing +term to break ultrasoft gauge invariance + + align:start position:0% +term to break ultrasoft gauge invariance + + + align:start position:0% +term to break ultrasoft gauge invariance +we're going to turn that I partial into + + align:start position:0% +we're going to turn that I partial into + + + align:start position:0% +we're going to turn that I partial into +a variant derivative under under the + + align:start position:0% +a variant derivative under under the + + + align:start position:0% +a variant derivative under under the +under we're going to include this piece + + align:start position:0% +under we're going to include this piece + + + align:start position:0% +under we're going to include this piece +here with the N.A ultrasoft to make it + + align:start position:0% +here with the N.A ultrasoft to make it + + + align:start position:0% +here with the N.A ultrasoft to make it +colinear to make it ultrasoft gauge in + + align:start position:0% +colinear to make it ultrasoft gauge in + + + align:start position:0% +colinear to make it ultrasoft gauge in +variant at lowest order okay so that's + + align:start position:0% +variant at lowest order okay so that's + + + align:start position:0% +variant at lowest order okay so that's +really the only comp other than just + + align:start position:0% +really the only comp other than just + + + align:start position:0% +really the only comp other than just +doing the sort of most naive thing by + + align:start position:0% +doing the sort of most naive thing by + + + align:start position:0% +doing the sort of most naive thing by +just replacing derivatives by coant + + align:start position:0% +just replacing derivatives by coant + + + align:start position:0% +just replacing derivatives by coant +derivatives and you might think well + + align:start position:0% +derivatives and you might think well + + + align:start position:0% +derivatives and you might think well +I'll just keep this as a partial + + align:start position:0% +I'll just keep this as a partial + + + align:start position:0% +I'll just keep this as a partial +derivative since it's doing gauge fixing + + align:start position:0% +derivative since it's doing gauge fixing + + + align:start position:0% +derivative since it's doing gauge fixing +I don't need to make it covariant but we + + align:start position:0% +I don't need to make it covariant but we + + + align:start position:0% +I don't need to make it covariant but we +do want to make it coari under the + + align:start position:0% +do want to make it coari under the + + + align:start position:0% +do want to make it coari under the +ultrasofts and that's why I write this + + align:start position:0% +ultrasofts and that's why I write this + + + align:start position:0% +ultrasofts and that's why I write this +curly the Ultra + + align:start position:0% +curly the Ultra + + + align:start position:0% +curly the Ultra +Soft okay so that gives you the leading + + align:start position:0% +Soft okay so that gives you the leading + + + align:start position:0% +Soft okay so that gives you the leading +order + + align:start position:0% +order + + + align:start position:0% +order +lran once you put together this with + + align:start position:0% +lran once you put together this with + + + align:start position:0% +lran once you put together this with +what you want for the ultrasoft then you + + align:start position:0% +what you want for the ultrasoft then you + + + align:start position:0% +what you want for the ultrasoft then you +would have the full leading order lran + + align:start position:0% +would have the full leading order lran + + + align:start position:0% +would have the full leading order lran +and the ultrasoft part is actually very + + align:start position:0% + + + + align:start position:0% + +simple so for the ultrasoft + + align:start position:0% +simple so for the ultrasoft + + + align:start position:0% +simple so for the ultrasoft +part we just take a a full qcd action + + align:start position:0% +part we just take a a full qcd action + + + align:start position:0% +part we just take a a full qcd action +for the ultrasoft field so this is just + + align:start position:0% +for the ultrasoft field so this is just + + + align:start position:0% +for the ultrasoft field so this is just +s ultrasoft or Q ultrasoft Bar + + align:start position:0% +s ultrasoft or Q ultrasoft Bar + + + align:start position:0% +s ultrasoft or Q ultrasoft Bar +id/ ultrasoft q ultrasoft and likewise + + align:start position:0% +id/ ultrasoft q ultrasoft and likewise + + + align:start position:0% +id/ ultrasoft q ultrasoft and likewise +for the for the gluon + + align:start position:0% + + + + align:start position:0% + +piece it's just + + align:start position:0% +piece it's just + + + align:start position:0% +piece it's just +qcd and we would do the gauge + + align:start position:0% +qcd and we would do the gauge + + + align:start position:0% +qcd and we would do the gauge +fixing without without thinking about uh + + align:start position:0% +fixing without without thinking about uh + + + align:start position:0% +fixing without without thinking about uh +any any complications like these ones + + align:start position:0% +any any complications like these ones + + + align:start position:0% +any any complications like these ones +and these are just involving ultrasoft + + align:start position:0% +and these are just involving ultrasoft + + + align:start position:0% +and these are just involving ultrasoft +Fields so just QC just ultrasoft + + align:start position:0% + + + + align:start position:0% + +Fields okay so the only place when you + + align:start position:0% +Fields okay so the only place when you + + + align:start position:0% +Fields okay so the only place when you +take everything here together the only + + align:start position:0% +take everything here together the only + + + align:start position:0% +take everything here together the only +place that the ultrasoft and cinear + + align:start position:0% +place that the ultrasoft and cinear + + + align:start position:0% +place that the ultrasoft and cinear +Fields talk to each other in the garage + + align:start position:0% +Fields talk to each other in the garage + + + align:start position:0% +Fields talk to each other in the garage +in is in this single component n. + + align:start position:0% +in is in this single component n. + + + align:start position:0% +in is in this single component n. +partial n. a ultrasoft and that comes + + align:start position:0% +partial n. a ultrasoft and that comes + + + align:start position:0% +partial n. a ultrasoft and that comes +about basically because + + align:start position:0% +about basically because + + + align:start position:0% +about basically because +of because of the power counting that + + align:start position:0% +of because of the power counting that + + + align:start position:0% +of because of the power counting that +this is really the only place that these + + align:start position:0% +this is really the only place that these + + + align:start position:0% +this is really the only place that these +two things can interact we'll talk about + + align:start position:0% +two things can interact we'll talk about + + + align:start position:0% +two things can interact we'll talk about +the implications of that later on + + align:start position:0% +the implications of that later on + + + align:start position:0% +the implications of that later on +on okay but that's the leading order ly + + align:start position:0% +on okay but that's the leading order ly + + + align:start position:0% +on okay but that's the leading order ly +so once you have this piece then this + + align:start position:0% +so once you have this piece then this + + + align:start position:0% +so once you have this piece then this +piece is pretty straightforward with + + align:start position:0% +piece is pretty straightforward with + + + align:start position:0% +piece is pretty straightforward with +this additional complication of worrying + + align:start position:0% +this additional complication of worrying + + + align:start position:0% +this additional complication of worrying +about what gauge symmetry means which + + align:start position:0% +about what gauge symmetry means which + + + align:start position:0% +about what gauge symmetry means which +we'll talk more about later but we had + + align:start position:0% +we'll talk more about later but we had + + + align:start position:0% +we'll talk more about later but we had +to be careful not to break it when we + + align:start position:0% +to be careful not to break it when we + + + align:start position:0% +to be careful not to break it when we +introduce this term because we want to + + align:start position:0% +introduce this term because we want to + + + align:start position:0% +introduce this term because we want to +in some sense have a gauge fixing both + + align:start position:0% +in some sense have a gauge fixing both + + + align:start position:0% +in some sense have a gauge fixing both +for the clinar Glon and a separate gauge + + align:start position:0% +for the clinar Glon and a separate gauge + + + align:start position:0% +for the clinar Glon and a separate gauge +fixing for the ultrasoft Glon and that's + + align:start position:0% +fixing for the ultrasoft Glon and that's + + + align:start position:0% +fixing for the ultrasoft Glon and that's +why we we wanted to do this and then + + align:start position:0% +why we we wanted to do this and then + + + align:start position:0% +why we we wanted to do this and then +this piece here is simple it's just qcd + + align:start position:0% +this piece here is simple it's just qcd + + + align:start position:0% +this piece here is simple it's just qcd +because it's + + align:start position:0% +because it's + + + align:start position:0% +because it's +if you like it's the lowest energy mode + + align:start position:0% +if you like it's the lowest energy mode + + + align:start position:0% +if you like it's the lowest energy mode +and it doesn't know about any of the + + align:start position:0% +and it doesn't know about any of the + + + align:start position:0% +and it doesn't know about any of the +complications that we had for the cinear + + align:start position:0% +complications that we had for the cinear + + + align:start position:0% +complications that we had for the cinear +modes okay so any questions about this + + align:start position:0% +modes okay so any questions about this + + + align:start position:0% +modes okay so any questions about this +so + + align:start position:0% + + + + align:start position:0% + +far okay so everything that we did in + + align:start position:0% +far okay so everything that we did in + + + align:start position:0% +far okay so everything that we did in +deriving these actions is tree + + align:start position:0% +deriving these actions is tree + + + align:start position:0% +deriving these actions is tree +level all the steps that we did were + + align:start position:0% +level all the steps that we did were + + + align:start position:0% +level all the steps that we did were +tree level so you can ask if I start to + + align:start position:0% +tree level so you can ask if I start to + + + align:start position:0% +tree level so you can ask if I start to +do loops will there be some Wilson + + align:start position:0% +do loops will there be some Wilson + + + align:start position:0% +do loops will there be some Wilson +coefficient that shows up somewhere here + + align:start position:0% +coefficient that shows up somewhere here + + + align:start position:0% +coefficient that shows up somewhere here +will I generate some new operators that + + align:start position:0% +will I generate some new operators that + + + align:start position:0% +will I generate some new operators that +I don't don't see here those are are + + align:start position:0% +I don't don't see here those are are + + + align:start position:0% +I don't don't see here those are are +reasonable questions and that's what + + align:start position:0% +reasonable questions and that's what + + + align:start position:0% +reasonable questions and that's what +we're going to address + + align:start position:0% + + + + align:start position:0% + +next so to go further we'll use + + align:start position:0% + + + + align:start position:0% + +symmetries and we're actually going to + + align:start position:0% +symmetries and we're actually going to + + + align:start position:0% +symmetries and we're actually going to +consider + + align:start position:0% +consider + + + align:start position:0% +consider +three different symmetries gauge + + align:start position:0% +three different symmetries gauge + + + align:start position:0% +three different symmetries gauge +symmetry which I've been promising you + + align:start position:0% +symmetry which I've been promising you + + + align:start position:0% +symmetry which I've been promising you +for a + + align:start position:0% +for a + + + align:start position:0% +for a +while reparameterization + + align:start position:0% + + + + align:start position:0% + +invariance and spin symmetry + + align:start position:0% + + + + align:start position:0% + +or I'll put a question mark by this last + + align:start position:0% +or I'll put a question mark by this last + + + align:start position:0% +or I'll put a question mark by this last +one because we need to answer the + + align:start position:0% +one because we need to answer the + + + align:start position:0% +one because we need to answer the +question whether there even is a spin + + align:start position:0% +question whether there even is a spin + + + align:start position:0% +question whether there even is a spin +symmetry these two here this number one + + align:start position:0% +symmetry these two here this number one + + + align:start position:0% +symmetry these two here this number one +and number two will turn out to + + align:start position:0% +and number two will turn out to + + + align:start position:0% +and number two will turn out to +be quite important number three is not + + align:start position:0% +be quite important number three is not + + + align:start position:0% +be quite important number three is not +so + + align:start position:0% + + + + align:start position:0% + +important so reparameterization + + align:start position:0% +important so reparameterization + + + align:start position:0% +important so reparameterization +invariance here will be like + + align:start position:0% +invariance here will be like + + + align:start position:0% +invariance here will be like +reparameterization invariance in HQ + + align:start position:0% +reparameterization invariance in HQ + + + align:start position:0% +reparameterization invariance in HQ +except now it's different we've + + align:start position:0% +except now it's different we've + + + align:start position:0% +except now it's different we've +introduced parameters n and n Bar and + + align:start position:0% +introduced parameters n and n Bar and + + + align:start position:0% +introduced parameters n and n Bar and +we'll have to see what kind of + + align:start position:0% +we'll have to see what kind of + + + align:start position:0% +we'll have to see what kind of +symmetries we have with those with + + align:start position:0% +symmetries we have with those with + + + align:start position:0% +symmetries we have with those with +respect to that that choice of basis + + align:start position:0% +respect to that that choice of basis + + + align:start position:0% +respect to that that choice of basis +vectors that we made but it otherwise + + align:start position:0% +vectors that we made but it otherwise + + + align:start position:0% +vectors that we made but it otherwise +will be analogous to our discussion of + + align:start position:0% + + + + align:start position:0% + +HQ so let's actually first dispense with + + align:start position:0% +HQ so let's actually first dispense with + + + align:start position:0% +HQ so let's actually first dispense with +the one that in some sense is the least + + align:start position:0% +the one that in some sense is the least + + + align:start position:0% +the one that in some sense is the least +important is number + + align:start position:0% + + + + align:start position:0% + +three so first let's revisit our + + align:start position:0% +three so first let's revisit our + + + align:start position:0% +three so first let's revisit our +Spinners a little bit + + align:start position:0% + + + + align:start position:0% + +so if I put together the information + + align:start position:0% +so if I put together the information + + + align:start position:0% +so if I put together the information +that we talked about when we derived the + + align:start position:0% +that we talked about when we derived the + + + align:start position:0% +that we talked about when we derived the +equation at the top of the board there + + align:start position:0% +equation at the top of the board there + + + align:start position:0% +equation at the top of the board there +for the + + align:start position:0% +for the + + + align:start position:0% +for the +larian we worked out that at tree + + align:start position:0% +larian we worked out that at tree + + + align:start position:0% +larian we worked out that at tree +level we have this + + align:start position:0% +level we have this + + + align:start position:0% +level we have this +formula that relates the + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +fields so from that formula if we just + + align:start position:0% +fields so from that formula if we just + + + align:start position:0% +fields so from that formula if we just +project onto the spinner pieces we can + + align:start position:0% +project onto the spinner pieces we can + + + align:start position:0% +project onto the spinner pieces we can +write down a formula that relates the + + align:start position:0% +write down a formula that relates the + + + align:start position:0% +write down a formula that relates the +Spinners so throwing away the the gauge + + align:start position:0% +Spinners so throwing away the the gauge + + + align:start position:0% +Spinners so throwing away the the gauge +fields we have in momentum space that U + + align:start position:0% +fields we have in momentum space that U + + + align:start position:0% +fields we have in momentum space that U +of P the + + align:start position:0% + + + + align:start position:0% + +spinner would be related to whatever + + align:start position:0% +spinner would be related to whatever + + + align:start position:0% +spinner would be related to whatever +spinner we have for this CN field which + + align:start position:0% +spinner we have for this CN field which + + + align:start position:0% +spinner we have for this CN field which +I call Un by that + + align:start position:0% +I call Un by that + + + align:start position:0% +I call Un by that +formula and then if you take this + + align:start position:0% +formula and then if you take this + + + align:start position:0% +formula and then if you take this +formula you also see that if I hit it + + align:start position:0% +formula you also see that if I hit it + + + align:start position:0% +formula you also see that if I hit it +with a projector + + align:start position:0% +with a projector + + + align:start position:0% +with a projector +n/n bar SL + + align:start position:0% +n/n bar SL + + + align:start position:0% +n/n bar SL +over4 if I hit hit the U with a + + align:start position:0% +over4 if I hit hit the U with a + + + align:start position:0% +over4 if I hit hit the U with a +projector it's going to kill this piece + + align:start position:0% +projector it's going to kill this piece + + + align:start position:0% +projector it's going to kill this piece +because the n n slash and bar slash can + + align:start position:0% +because the n n slash and bar slash can + + + align:start position:0% +because the n n slash and bar slash can +be pushed through the P per slash and + + align:start position:0% +be pushed through the P per slash and + + + align:start position:0% +be pushed through the P per slash and +then n bar squar is zero so that kills + + align:start position:0% +then n bar squar is zero so that kills + + + align:start position:0% +then n bar squar is zero so that kills +that second piece so we also have this + + align:start position:0% +that second piece so we also have this + + + align:start position:0% +that second piece so we also have this +formula and then once you have this + + align:start position:0% +formula and then once you have this + + + align:start position:0% +formula and then once you have this +formula you + + align:start position:0% +formula you + + + align:start position:0% +formula you +have the formulas that we kind of wanted + + align:start position:0% +have the formulas that we kind of wanted + + + align:start position:0% +have the formulas that we kind of wanted +for that + + align:start position:0% + + + + align:start position:0% + +okay but this actually this spinner here + + align:start position:0% +okay but this actually this spinner here + + + align:start position:0% +okay but this actually this spinner here +this un is not exactly the same as the + + align:start position:0% +this un is not exactly the same as the + + + align:start position:0% +this un is not exactly the same as the +spinner that we talked about + + align:start position:0% +spinner that we talked about + + + align:start position:0% +spinner that we talked about +earlier uh so let me come back let me + + align:start position:0% +earlier uh so let me come back let me + + + align:start position:0% +earlier uh so let me come back let me +come to that in a + + align:start position:0% +come to that in a + + + align:start position:0% +come to that in a +minute so first thing you might consider + + align:start position:0% +minute so first thing you might consider + + + align:start position:0% +minute so first thing you might consider +is whether when I take this + + align:start position:0% +is whether when I take this + + + align:start position:0% +is whether when I take this +CN field and I take the lran up at the + + align:start position:0% +CN field and I take the lran up at the + + + align:start position:0% +CN field and I take the lran up at the +top of the board do I just get the + + align:start position:0% +top of the board do I just get the + + + align:start position:0% +top of the board do I just get the +clinar propagator that we talked about + + align:start position:0% +clinar propagator that we talked about + + + align:start position:0% +clinar propagator that we talked about +and indeed you do + + align:start position:0% +and indeed you do + + + align:start position:0% +and indeed you do +so if + + align:start position:0% +so if + + + align:start position:0% +so if +you if you consider it's kind of obvious + + align:start position:0% +you if you consider it's kind of obvious + + + align:start position:0% +you if you consider it's kind of obvious +for the momentum dependent parts and + + align:start position:0% +for the momentum dependent parts and + + + align:start position:0% +for the momentum dependent parts and +really you might only worry about the + + align:start position:0% +really you might only worry about the + + + align:start position:0% +really you might only worry about the +spin and so if you + + align:start position:0% +spin and so if you + + + align:start position:0% +spin and so if you +consider this formula and you consider + + align:start position:0% +consider this formula and you consider + + + align:start position:0% +consider this formula and you consider +the sum over + + align:start position:0% +the sum over + + + align:start position:0% +the sum over +spins of U Bar which is what's going to + + align:start position:0% +spins of U Bar which is what's going to + + + align:start position:0% +spins of U Bar which is what's going to +appear in the numerator of the + + align:start position:0% +appear in the numerator of the + + + align:start position:0% +appear in the numerator of the +propagator for the firon when you're + + align:start position:0% +propagator for the firon when you're + + + align:start position:0% +propagator for the firon when you're +deriving the firon propagator you get a + + align:start position:0% +deriving the firon propagator you get a + + + align:start position:0% +deriving the firon propagator you get a +sum over the physical + + align:start position:0% +sum over the physical + + + align:start position:0% +sum over the physical +spins then from this formula this is a + + align:start position:0% +spins then from this formula this is a + + + align:start position:0% +spins then from this formula this is a +projector + + align:start position:0% +projector + + + align:start position:0% +projector +on something you know how to do the spin + + align:start position:0% +on something you know how to do the spin + + + align:start position:0% +on something you know how to do the spin +sum + + align:start position:0% + + + + align:start position:0% + +for which is the full + + align:start position:0% +for which is the full + + + align:start position:0% +for which is the full +Theory + + align:start position:0% + + + + align:start position:0% + +spinner and that spin sum is just P + + align:start position:0% +spinner and that spin sum is just P + + + align:start position:0% +spinner and that spin sum is just P +slash so this is like P slash sandwiched + + align:start position:0% +slash so this is like P slash sandwiched + + + align:start position:0% +slash so this is like P slash sandwiched +between + + align:start position:0% + + + + align:start position:0% + +projectors and you can work out that + + align:start position:0% +projectors and you can work out that + + + align:start position:0% +projectors and you can work out that +that's + + align:start position:0% +that's + + + align:start position:0% +that's +exactly the numerator that we had + + align:start position:0% + + + + align:start position:0% + +before after a little bit of dra + + align:start position:0% + + + + align:start position:0% + +algebra so that part works as expected + + align:start position:0% +algebra so that part works as expected + + + align:start position:0% +algebra so that part works as expected +we if we take this lran and we work out + + align:start position:0% +we if we take this lran and we work out + + + align:start position:0% +we if we take this lran and we work out +what the propagator is we get exactly + + align:start position:0% +what the propagator is we get exactly + + + align:start position:0% +what the propagator is we get exactly +the propagator we got from expansion + + align:start position:0% + + + + align:start position:0% + +so quantizing LC c0 gives us that + + align:start position:0% + + + + align:start position:0% + +propagator but the situation is not + + align:start position:0% +propagator but the situation is not + + + align:start position:0% +propagator but the situation is not +quite the same for the spinner + + align:start position:0% + + + + align:start position:0% + +and in some sense this is not this this + + align:start position:0% +and in some sense this is not this this + + + align:start position:0% +and in some sense this is not this this +point is not absolutely crucial but + + align:start position:0% +point is not absolutely crucial but + + + align:start position:0% +point is not absolutely crucial but +actually because I there's a little + + align:start position:0% +actually because I there's a little + + + align:start position:0% +actually because I there's a little +simplification I want to do in order to + + align:start position:0% +simplification I want to do in order to + + + align:start position:0% +simplification I want to do in order to +discuss the spin Symmetry and in order + + align:start position:0% +discuss the spin Symmetry and in order + + + align:start position:0% +discuss the spin Symmetry and in order +to do that this point it it it's + + align:start position:0% +to do that this point it it it's + + + align:start position:0% +to do that this point it it it's +important to understand this point so + + align:start position:0% +important to understand this point so + + + align:start position:0% +important to understand this point so +that I'm going through this in some + + align:start position:0% +that I'm going through this in some + + + align:start position:0% +that I'm going through this in some +sense because then it'll be very easy to + + align:start position:0% +sense because then it'll be very easy to + + + align:start position:0% +sense because then it'll be very easy to +discuss what spin symmetry we have in + + align:start position:0% +discuss what spin symmetry we have in + + + align:start position:0% +discuss what spin symmetry we have in +the + + align:start position:0% + + + + align:start position:0% + +theory so this guy is actually not equal + + align:start position:0% +theory so this guy is actually not equal + + + align:start position:0% +theory so this guy is actually not equal +to our expanded + + align:start position:0% +to our expanded + + + align:start position:0% +to our expanded +spinner + + align:start position:0% +spinner + + + align:start position:0% +spinner +which putting in some + + align:start position:0% +which putting in some + + + align:start position:0% +which putting in some +normalization I could + + align:start position:0% +normalization I could + + + align:start position:0% +normalization I could +write like + + align:start position:0% +write like + + + align:start position:0% +write like +this which so this is what we got by + + align:start position:0% +this which so this is what we got by + + + align:start position:0% +this which so this is what we got by +expanding some thing like this which is + + align:start position:0% +expanding some thing like this which is + + + align:start position:0% +expanding some thing like this which is +very simple where this U was equal to 1 + + align:start position:0% +very simple where this U was equal to 1 + + + align:start position:0% +very simple where this U was equal to 1 +0 or 01 + + align:start position:0% +0 or 01 + + + align:start position:0% +0 or 01 +in the direct + + align:start position:0% +in the direct + + + align:start position:0% +in the direct +representation but that's actually not + + align:start position:0% +representation but that's actually not + + + align:start position:0% +representation but that's actually not +what we get if we just take the formula + + align:start position:0% +what we get if we just take the formula + + + align:start position:0% +what we get if we just take the formula +up + + align:start position:0% +up + + + align:start position:0% +up +here and use + + align:start position:0% + + + + align:start position:0% + +this so let's see what we do get + + align:start position:0% + + + + align:start position:0% + +so if you use the formula up + + align:start position:0% +so if you use the formula up + + + align:start position:0% +so if you use the formula up +there and you have the + + align:start position:0% + + + + align:start position:0% + +following so here's the F Theory spinner + + align:start position:0% +following so here's the F Theory spinner + + + align:start position:0% +following so here's the F Theory spinner +with sort of a conventional + + align:start position:0% + + + + align:start position:0% + +normalization this thing and this thing + + align:start position:0% +normalization this thing and this thing + + + align:start position:0% +normalization this thing and this thing +here is the + + align:start position:0% +here is the + + + align:start position:0% +here is the +projector okay + + align:start position:0% +projector okay + + + align:start position:0% +projector okay +so you could work out what that product + + align:start position:0% +so you could work out what that product + + + align:start position:0% +so you could work out what that product +is and it turns out that you can write + + align:start position:0% +is and it turns out that you can write + + + align:start position:0% +is and it turns out that you can write +it in the following way which + + align:start position:0% +it in the following way which + + + align:start position:0% +it in the following way which +is very closely related but not + + align:start position:0% +is very closely related but not + + + align:start position:0% +is very closely related but not +precisely the + + align:start position:0% +precisely the + + + align:start position:0% +precisely the +same as what we had + + align:start position:0% +same as what we had + + + align:start position:0% +same as what we had +before so you can write it in what looks + + align:start position:0% +before so you can write it in what looks + + + align:start position:0% +before so you can write it in what looks +like the same + + align:start position:0% +like the same + + + align:start position:0% +like the same +form as we have over here except this + + align:start position:0% +form as we have over here except this + + + align:start position:0% +form as we have over here except this +curly U curly capital + + align:start position:0% +curly U curly capital + + + align:start position:0% +curly U curly capital +u is a more complicated object + + align:start position:0% + + + + align:start position:0% + +and it's just whatever I get by + + align:start position:0% +and it's just whatever I get by + + + align:start position:0% +and it's just whatever I get by +multiplying these two things out which + + align:start position:0% +multiplying these two things out which + + + align:start position:0% +multiplying these two things out which +turns out to be something I can write in + + align:start position:0% +turns out to be something I can write in + + + align:start position:0% +turns out to be something I can write in +that + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% + + + + align:start position:0% + +form so it's some two compon + + align:start position:0% + + + + align:start position:0% + +spinner but it's got momentum dependence + + align:start position:0% +spinner but it's got momentum dependence + + + align:start position:0% +spinner but it's got momentum dependence +unlike our simple one + + align:start position:0% +unlike our simple one + + + align:start position:0% +unlike our simple one +Z and + + align:start position:0% + + + + align:start position:0% + +01 but everything we said about un + + align:start position:0% +01 but everything we said about un + + + align:start position:0% +01 but everything we said about un +really depended only on the fact that it + + align:start position:0% +really depended only on the fact that it + + + align:start position:0% +really depended only on the fact that it +could have be written in this form in + + align:start position:0% +could have be written in this form in + + + align:start position:0% +could have be written in this form in +terms of some two component spinner the + + align:start position:0% +terms of some two component spinner the + + + align:start position:0% +terms of some two component spinner the +fact that n slash on it was Zero the + + align:start position:0% +fact that n slash on it was Zero the + + + align:start position:0% +fact that n slash on it was Zero the +fact that it had projection relation so + + align:start position:0% +fact that it had projection relation so + + + align:start position:0% +fact that it had projection relation so +these formulas here once you have once + + align:start position:0% +these formulas here once you have once + + + align:start position:0% +these formulas here once you have once +you have you know if you have a formula + + align:start position:0% +you have you know if you have a formula + + + align:start position:0% +you have you know if you have a formula +like is these formulas here are + + align:start position:0% +like is these formulas here are + + + align:start position:0% +like is these formulas here are +true + + align:start position:0% +true + + + align:start position:0% +true +okay so actually it would be true + + align:start position:0% +okay so actually it would be true + + + align:start position:0% +okay so actually it would be true +whatever spinner we have there so why + + align:start position:0% +whatever spinner we have there so why + + + align:start position:0% +whatever spinner we have there so why +should I why should I want this U + + align:start position:0% +should I why should I want this U + + + align:start position:0% +should I why should I want this U +twiddle spinner rather than the U the U + + align:start position:0% + + + + align:start position:0% + +spinner that actually has to do with + + align:start position:0% +spinner that actually has to do with + + + align:start position:0% +spinner that actually has to do with +this reparameterization in variance so + + align:start position:0% +this reparameterization in variance so + + + align:start position:0% +this reparameterization in variance so +it'll + + align:start position:0% +it'll + + + align:start position:0% +it'll +become clear when we talk about + + align:start position:0% +become clear when we talk about + + + align:start position:0% +become clear when we talk about +that but these extra terms in + + align:start position:0% +that but these extra terms in + + + align:start position:0% +that but these extra terms in +u relative to those for the other guy + + align:start position:0% +u relative to those for the other guy + + + align:start position:0% +u relative to those for the other guy +the simple + + align:start position:0% + + + + align:start position:0% + +U actually inser the proper + + align:start position:0% +U actually inser the proper + + + align:start position:0% +U actually inser the proper +structure under + + align:start position:0% + + + + align:start position:0% + +reparametrizations and + + align:start position:0% +reparametrizations and + + + align:start position:0% +reparametrizations and +basically it'll come become clear at a + + align:start position:0% +basically it'll come become clear at a + + + align:start position:0% +basically it'll come become clear at a +moment but basically if we wanted to get + + align:start position:0% +moment but basically if we wanted to get + + + align:start position:0% +moment but basically if we wanted to get +this U spinner we should have a slightly + + align:start position:0% +this U spinner we should have a slightly + + + align:start position:0% +this U spinner we should have a slightly +different projector + + align:start position:0% + + + + align:start position:0% + +which I'll call PN + + align:start position:0% +which I'll call PN + + + align:start position:0% +which I'll call PN +Prime and + + align:start position:0% + + + + align:start position:0% + +it's so we could have used a different + + align:start position:0% +it's so we could have used a different + + + align:start position:0% +it's so we could have used a different +projector which is this + + align:start position:0% +projector which is this + + + align:start position:0% +projector which is this +one and then we could have come up with + + align:start position:0% +one and then we could have come up with + + + align:start position:0% +one and then we could have come up with +a another projector which was the PN bar + + align:start position:0% +a another projector which was the PN bar + + + align:start position:0% +a another projector which was the PN bar +projector which would satisfy that the + + align:start position:0% +projector which would satisfy that the + + + align:start position:0% +projector which would satisfy that the +sum is + + align:start position:0% + + + + align:start position:0% + +one if we wanted and this projector here + + align:start position:0% +one if we wanted and this projector here + + + align:start position:0% +one if we wanted and this projector here +when acting on the full Theory spinner + + align:start position:0% +when acting on the full Theory spinner + + + align:start position:0% +when acting on the full Theory spinner +would have the full Theory field would + + align:start position:0% +would have the full Theory field would + + + align:start position:0% +would have the full Theory field would +have given something that would have + + align:start position:0% +have given something that would have + + + align:start position:0% +have given something that would have +been proportional to this combination + + align:start position:0% +been proportional to this combination + + + align:start position:0% +been proportional to this combination +over here okay so you just have to + + align:start position:0% +over here okay so you just have to + + + align:start position:0% +over here okay so you just have to +believe me I don't want to go through + + align:start position:0% +believe me I don't want to go through + + + align:start position:0% +believe me I don't want to go through +the algebra or you can check it yourself + + align:start position:0% +the algebra or you can check it yourself + + + align:start position:0% +the algebra or you can check it yourself +but this projector here is not in + + align:start position:0% +but this projector here is not in + + + align:start position:0% +but this projector here is not in +invariant under that symmetry of + + align:start position:0% +invariant under that symmetry of + + + align:start position:0% +invariant under that symmetry of +reparameterization invariance + + align:start position:0% + + + + align:start position:0% + +so when we talk about RPI it'll be clear + + align:start position:0% +so when we talk about RPI it'll be clear + + + align:start position:0% +so when we talk about RPI it'll be clear +why we want a projector which is this + + align:start position:0% +why we want a projector which is this + + + align:start position:0% +why we want a projector which is this +projector and not the slightly different + + align:start position:0% +projector and not the slightly different + + + align:start position:0% +projector and not the slightly different +projector which is this extra has this + + align:start position:0% +projector which is this extra has this + + + align:start position:0% +projector which is this extra has this +extra in slash over + + align:start position:0% + + + + align:start position:0% + +two okay but nevertheless the important + + align:start position:0% +two okay but nevertheless the important + + + align:start position:0% +two okay but nevertheless the important +point that I wanted to emphasize + + align:start position:0% +point that I wanted to emphasize + + + align:start position:0% +point that I wanted to emphasize +is really that we have this kind of way + + align:start position:0% +is really that we have this kind of way + + + align:start position:0% +is really that we have this kind of way +of + + align:start position:0% +of + + + align:start position:0% +of +decomposing the spinner the true spinner + + align:start position:0% +decomposing the spinner the true spinner + + + align:start position:0% +decomposing the spinner the true spinner +for our field CN in terms of a two + + align:start position:0% +for our field CN in terms of a two + + + align:start position:0% +for our field CN in terms of a two +component object you + + align:start position:0% +component object you + + + align:start position:0% +component object you +twiddle okay so this + + align:start position:0% +twiddle okay so this + + + align:start position:0% +twiddle okay so this +is we are able to do that and if you + + align:start position:0% +is we are able to do that and if you + + + align:start position:0% +is we are able to do that and if you +want to talk about spin symmetry of the + + align:start position:0% +want to talk about spin symmetry of the + + + align:start position:0% +want to talk about spin symmetry of the +theory it's easier if you use a two + + align:start position:0% +theory it's easier if you use a two + + + align:start position:0% +theory it's easier if you use a two +component notation so the reason that I + + align:start position:0% +component notation so the reason that I + + + align:start position:0% +component notation so the reason that I +wanted to go through this is really to + + align:start position:0% +wanted to go through this is really to + + + align:start position:0% +wanted to go through this is really to +have on the board this equation which I + + align:start position:0% +have on the board this equation which I + + + align:start position:0% +have on the board this equation which I +can then use to motivate writing down a + + align:start position:0% +can then use to motivate writing down a + + + align:start position:0% +can then use to motivate writing down a +two component version of CN + + align:start position:0% +two component version of CN + + + align:start position:0% +two component version of CN +once I have a two component version of + + align:start position:0% +once I have a two component version of + + + align:start position:0% +once I have a two component version of +then it's very easy to see what the spin + + align:start position:0% +then it's very easy to see what the spin + + + align:start position:0% +then it's very easy to see what the spin +symmetry + + align:start position:0% + + + + align:start position:0% + +is so let's write down this two + + align:start position:0% +is so let's write down this two + + + align:start position:0% +is so let's write down this two +component version of our cleaner cork + + align:start position:0% + + + + align:start position:0% + +lran you can do the same thing of course + + align:start position:0% +lran you can do the same thing of course + + + align:start position:0% +lran you can do the same thing of course +in hqt right down a two component + + align:start position:0% +in hqt right down a two component + + + align:start position:0% +in hqt right down a two component +version rather than a four component + + align:start position:0% +version rather than a four component + + + align:start position:0% +version rather than a four component +version if you have a four component + + align:start position:0% +version if you have a four component + + + align:start position:0% +version if you have a four component +version has this projection relation if + + align:start position:0% +version has this projection relation if + + + align:start position:0% +version has this projection relation if +you have the two component version the + + align:start position:0% +you have the two component version the + + + align:start position:0% +you have the two component version the +projection relation is built + + align:start position:0% + + + + align:start position:0% + +in the reason to consider the four + + align:start position:0% +in the reason to consider the four + + + align:start position:0% +in the reason to consider the four +component version is if you want to + + align:start position:0% +component version is if you want to + + + align:start position:0% +component version is if you want to +couple four component this object to + + align:start position:0% +couple four component this object to + + + align:start position:0% +couple four component this object to +four component Fields like the ultrasoft + + align:start position:0% +four component Fields like the ultrasoft + + + align:start position:0% +four component Fields like the ultrasoft +field then it's of course a nice thing + + align:start position:0% +field then it's of course a nice thing + + + align:start position:0% +field then it's of course a nice thing +to have a four component + + align:start position:0% +to have a four component + + + align:start position:0% +to have a four component +version but some things are easier in + + align:start position:0% +version but some things are easier in + + + align:start position:0% +version but some things are easier in +two components + + align:start position:0% + + + + align:start position:0% + +so take + + align:start position:0% +so take + + + align:start position:0% +so take +CN and write + + align:start position:0% +CN and write + + + align:start position:0% +CN and write +it as + + align:start position:0% + + + + align:start position:0% + +follows with this F in is two components + + align:start position:0% +follows with this F in is two components + + + align:start position:0% +follows with this F in is two components +and I've set things up so the dimensions + + align:start position:0% +and I've set things up so the dimensions + + + align:start position:0% +and I've set things up so the dimensions +of CN are equal to the dimensions of + + align:start position:0% + + + + align:start position:0% + +f okay so I can take that formula plug + + align:start position:0% +f okay so I can take that formula plug + + + align:start position:0% +f okay so I can take that formula plug +it into our lran + + align:start position:0% + + + + align:start position:0% + +and then I can using the direct + + align:start position:0% +and then I can using the direct + + + align:start position:0% +and then I can using the direct +representation for the gamma + + align:start position:0% +representation for the gamma + + + align:start position:0% +representation for the gamma +matrices write out a lran for + + align:start position:0% +matrices write out a lran for + + + align:start position:0% +matrices write out a lran for +this + + align:start position:0% + + + + align:start position:0% + +F so that requires doing a bit of + + align:start position:0% +F so that requires doing a bit of + + + align:start position:0% +F so that requires doing a bit of +algebra which I + + align:start position:0% +algebra which I + + + align:start position:0% +algebra which I +will take you through + + align:start position:0% + + + + align:start position:0% + +and then we get an equivalent LR in but + + align:start position:0% +and then we get an equivalent LR in but + + + align:start position:0% +and then we get an equivalent LR in but +in terms of this field and it looks as + + align:start position:0% +in terms of this field and it looks as + + + align:start position:0% +in terms of this field and it looks as +follows + + align:start position:0% + + + + align:start position:0% + +okay so it's almost independent of spin + + align:start position:0% +okay so it's almost independent of spin + + + align:start position:0% +okay so it's almost independent of spin +but not quite there's this Sigma 3 + + align:start position:0% +but not quite there's this Sigma 3 + + + align:start position:0% +but not quite there's this Sigma 3 +sitting there if Sigma 3 wasn't there + + align:start position:0% +sitting there if Sigma 3 wasn't there + + + align:start position:0% +sitting there if Sigma 3 wasn't there +like hqt where you'd have an su2 + + align:start position:0% +like hqt where you'd have an su2 + + + align:start position:0% +like hqt where you'd have an su2 +symmetry the fact that Sigma 3 is there + + align:start position:0% +symmetry the fact that Sigma 3 is there + + + align:start position:0% +symmetry the fact that Sigma 3 is there +means you don't have an su3 su2 + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% + + + + align:start position:0% + +Symmetry and really all you have is a U1 + + align:start position:0% + + + + align:start position:0% + +Symmetry and that U1 corresponds just to + + align:start position:0% + + + + align:start position:0% + +helicity so in four component + + align:start position:0% +helicity so in four component + + + align:start position:0% +helicity so in four component +notation that U1 would be + + align:start position:0% + + + + align:start position:0% + +following projecting the spin operator + + align:start position:0% +following projecting the spin operator + + + align:start position:0% +following projecting the spin operator +onto perpendicular indices anti- + + align:start position:0% +onto perpendicular indices anti- + + + align:start position:0% +onto perpendicular indices anti- +symmetric in both of them and in the two + + align:start position:0% +symmetric in both of them and in the two + + + align:start position:0% +symmetric in both of them and in the two +component that just becomes a + + align:start position:0% +component that just becomes a + + + align:start position:0% +component that just becomes a +sigma3 so obviously if we do an + + align:start position:0% +sigma3 so obviously if we do an + + + align:start position:0% +sigma3 so obviously if we do an +exponential rotation with respect to + + align:start position:0% +exponential rotation with respect to + + + align:start position:0% +exponential rotation with respect to +Sigma 3 Sigma 3 commutes with Sigma 3 so + + align:start position:0% +Sigma 3 Sigma 3 commutes with Sigma 3 so + + + align:start position:0% +Sigma 3 Sigma 3 commutes with Sigma 3 so +does the identity and so we could have a + + align:start position:0% +does the identity and so we could have a + + + align:start position:0% +does the identity and so we could have a +rotation of this guy by + + align:start position:0% +rotation of this guy by + + + align:start position:0% +rotation of this guy by +that and that's the only that's the only + + align:start position:0% +that and that's the only that's the only + + + align:start position:0% +that and that's the only that's the only +spin symmetry that you have is the + + align:start position:0% + + + + align:start position:0% + +solcity and and so because of the + + align:start position:0% +solcity and and so because of the + + + align:start position:0% +solcity and and so because of the +coordinates we're using this corresponds + + align:start position:0% +coordinates we're using this corresponds + + + align:start position:0% +coordinates we're using this corresponds +to the spin along the direction of + + align:start position:0% +to the spin along the direction of + + + align:start position:0% +to the spin along the direction of +motion which is the three direction if + + align:start position:0% +motion which is the three direction if + + + align:start position:0% +motion which is the three direction if +you + + align:start position:0% +you + + + align:start position:0% +you +like which sometimes we denote by just + + align:start position:0% +like which sometimes we denote by just + + + align:start position:0% +like which sometimes we denote by just +saying it's along the direction n which + + align:start position:0% +saying it's along the direction n which + + + align:start position:0% +saying it's along the direction n which +is then more more independent of how we + + align:start position:0% +is then more more independent of how we + + + align:start position:0% +is then more more independent of how we +pick our + + align:start position:0% +pick our + + + align:start position:0% +pick our +axes so this is this symmetry here is + + align:start position:0% +axes so this is this symmetry here is + + + align:start position:0% +axes so this is this symmetry here is +actually related to what you would call + + align:start position:0% +actually related to what you would call + + + align:start position:0% +actually related to what you would call +the chirality in qcd so it's not + + align:start position:0% +the chirality in qcd so it's not + + + align:start position:0% +the chirality in qcd so it's not +really it's not really a new symmetry + + align:start position:0% +really it's not really a new symmetry + + + align:start position:0% +really it's not really a new symmetry +[Applause] + + align:start position:0% + + + + align:start position:0% + +so this is just related to the chyo + + align:start position:0% + + + + align:start position:0% + +rotation so if you look at Gamma 5 * + + align:start position:0% +rotation so if you look at Gamma 5 * + + + align:start position:0% +rotation so if you look at Gamma 5 * +C and Gamma 5 in our representation + + align:start position:0% +C and Gamma 5 in our representation + + + align:start position:0% +C and Gamma 5 in our representation +would be 0 1 1 + + align:start position:0% +would be 0 1 1 + + + align:start position:0% +would be 0 1 1 +0 and then if I write it + + align:start position:0% +0 and then if I write it + + + align:start position:0% +0 and then if I write it +out terms of this two component + + align:start position:0% + + + + align:start position:0% + +thing then that is just giving me 1/ < + + align:start position:0% +thing then that is just giving me 1/ < + + + align:start position:0% +thing then that is just giving me 1/ < +tk2 + + align:start position:0% + + + + align:start position:0% + +and it's swapping up and + + align:start position:0% +and it's swapping up and + + + align:start position:0% +and it's swapping up and +down and so that just means that FN has + + align:start position:0% +down and so that just means that FN has + + + align:start position:0% +down and so that just means that FN has +gone to Sigma 3 + + align:start position:0% +gone to Sigma 3 + + + align:start position:0% +gone to Sigma 3 +FN so multiplying by gamma 5 is actually + + align:start position:0% +FN so multiplying by gamma 5 is actually + + + align:start position:0% +FN so multiplying by gamma 5 is actually +the same as multiplying by Sigma 3 the + + align:start position:0% +the same as multiplying by Sigma 3 the + + + align:start position:0% +the same as multiplying by Sigma 3 the +two component notation okay so this SYM + + align:start position:0% +two component notation okay so this SYM + + + align:start position:0% +two component notation okay so this SYM +this is not really new Symmetry and + + align:start position:0% +this is not really new Symmetry and + + + align:start position:0% +this is not really new Symmetry and +actually all the usual things that you + + align:start position:0% +actually all the usual things that you + + + align:start position:0% +actually all the usual things that you +would say about kyl rotations in qcd + + align:start position:0% +would say about kyl rotations in qcd + + + align:start position:0% +would say about kyl rotations in qcd +would + + align:start position:0% +would + + + align:start position:0% +would +apply here too so kyl rotations of + + align:start position:0% +apply here too so kyl rotations of + + + align:start position:0% +apply here too so kyl rotations of +course are not exact col rotations are + + align:start position:0% +course are not exact col rotations are + + + align:start position:0% +course are not exact col rotations are +broken by masses col rotations are + + align:start position:0% +broken by masses col rotations are + + + align:start position:0% +broken by masses col rotations are +broken by non-perturbative + + align:start position:0% +broken by non-perturbative + + + align:start position:0% +broken by non-perturbative +effects there you can worry about + + align:start position:0% +effects there you can worry about + + + align:start position:0% +effects there you can worry about +anomalies they are useful in peration + + align:start position:0% +anomalies they are useful in peration + + + align:start position:0% +anomalies they are useful in peration +theory for quantifying operators and + + align:start position:0% +theory for quantifying operators and + + + align:start position:0% +theory for quantifying operators and +that remains true here but if the cinar + + align:start position:0% +that remains true here but if the cinar + + + align:start position:0% +that remains true here but if the cinar +fields were non-perturbative then you + + align:start position:0% +fields were non-perturbative then you + + + align:start position:0% +fields were non-perturbative then you +should worry about those other things as + + align:start position:0% + + + + align:start position:0% + +well okay so spin symmetry there's not + + align:start position:0% +well okay so spin symmetry there's not + + + align:start position:0% +well okay so spin symmetry there's not +really any new anything new there to + + align:start position:0% +really any new anything new there to + + + align:start position:0% +really any new anything new there to +talk + + align:start position:0% +talk + + + align:start position:0% +talk +about but along the way we saw we could + + align:start position:0% +about but along the way we saw we could + + + align:start position:0% +about but along the way we saw we could +write in two component form which is + + align:start position:0% +write in two component form which is + + + align:start position:0% +write in two component form which is +kind of + + align:start position:0% +kind of + + + align:start position:0% +kind of +nice so let's talk about something + + align:start position:0% +nice so let's talk about something + + + align:start position:0% +nice so let's talk about something +that's more important which is gauge + + align:start position:0% +that's more important which is gauge + + + align:start position:0% +that's more important which is gauge +symmetry is there any questions about + + align:start position:0% +symmetry is there any questions about + + + align:start position:0% +symmetry is there any questions about +the spins before we talk about gauge + + align:start position:0% + + + + align:start position:0% + +symmetry so is they actually turned off + + align:start position:0% +symmetry so is they actually turned off + + + align:start position:0% +symmetry so is they actually turned off +integrating out the + + align:start position:0% + + + + align:start position:0% + +that is why you had the minus SL + + align:start position:0% +that is why you had the minus SL + + + align:start position:0% +that is why you had the minus SL +projectors and why you don't have the + + align:start position:0% +projectors and why you don't have the + + + align:start position:0% +projectors and why you don't have the +full + + align:start position:0% +full + + + align:start position:0% +full +su2 like that + + align:start position:0% + + + + align:start position:0% + +um yeah + + align:start position:0% + + + + align:start position:0% + +um I looked at it once but it's hard for + + align:start position:0% +um I looked at it once but it's hard for + + + align:start position:0% +um I looked at it once but it's hard for +me to remember the answer I think not + + align:start position:0% +me to remember the answer I think not + + + align:start position:0% +me to remember the answer I think not +but I think if you do the other version + + align:start position:0% +but I think if you do the other version + + + align:start position:0% +but I think if you do the other version +then you just get something more + + align:start position:0% +then you just get something more + + + align:start position:0% +then you just get something more +complicated here but still breaks su2 + + align:start position:0% +complicated here but still breaks su2 + + + align:start position:0% +complicated here but still breaks su2 +like it okay + + align:start position:0% +like it okay + + + align:start position:0% +like it okay +yeah I'm just looking + + align:start position:0% +yeah I'm just looking + + + align:start position:0% +yeah I'm just looking +yeah so they're two two disconnected + + align:start position:0% +yeah so they're two two disconnected + + + align:start position:0% +yeah so they're two two disconnected +fact that other the thing that you know + + align:start position:0% +fact that other the thing that you know + + + align:start position:0% +fact that other the thing that you know +that I wanted to motivate that I could + + align:start position:0% +that I wanted to motivate that I could + + + align:start position:0% +that I wanted to motivate that I could +use this formula and I wanted to be + + align:start position:0% +use this formula and I wanted to be + + + align:start position:0% +use this formula and I wanted to be +honest with you about where that came + + align:start position:0% +honest with you about where that came + + + align:start position:0% +honest with you about where that came +from and that's why I told you this + + align:start position:0% +from and that's why I told you this + + + align:start position:0% +from and that's why I told you this +other fact but once but I could have + + align:start position:0% +other fact but once but I could have + + + align:start position:0% +other fact but once but I could have +jumped right here and said remember and + + align:start position:0% +jumped right here and said remember and + + + align:start position:0% +jumped right here and said remember and +glossed over it and that would have been + + align:start position:0% +glossed over it and that would have been + + + align:start position:0% +glossed over it and that would have been +fine for this discussion so they're in + + align:start position:0% +fine for this discussion so they're in + + + align:start position:0% +fine for this discussion so they're in +some sense two disconnected things at + + align:start position:0% +some sense two disconnected things at + + + align:start position:0% +some sense two disconnected things at +least in my mind + + align:start position:0% +least in my mind + + + align:start position:0% +least in my mind +do you have some intuition for what + + align:start position:0% +do you have some intuition for what + + + align:start position:0% +do you have some intuition for what +Theta n bar + + align:start position:0% +Theta n bar + + + align:start position:0% +Theta n bar +is for Theta n Bar the + + align:start position:0% +is for Theta n Bar the + + + align:start position:0% +is for Theta n Bar the +thing oh the yeah I mean it's it's + + align:start position:0% +thing oh the yeah I mean it's it's + + + align:start position:0% +thing oh the yeah I mean it's it's +really just saying the my intuition for + + align:start position:0% +really just saying the my intuition for + + + align:start position:0% +really just saying the my intuition for +it is really just that when you're + + align:start position:0% +it is really just that when you're + + + align:start position:0% +it is really just that when you're +producing energetic particles you you + + align:start position:0% +producing energetic particles you you + + + align:start position:0% +producing energetic particles you you +know it's what we did at the beginning + + align:start position:0% +know it's what we did at the beginning + + + align:start position:0% +know it's what we did at the beginning +when you're intro when you're when + + align:start position:0% +when you're intro when you're when + + + align:start position:0% +when you're intro when you're when +you're producing energetic particles + + align:start position:0% +you're producing energetic particles + + + align:start position:0% +you're producing energetic particles +these are the spin components that you + + align:start position:0% +these are the spin components that you + + + align:start position:0% +these are the spin components that you +have at lowest order and that leads to + + align:start position:0% +have at lowest order and that leads to + + + align:start position:0% +have at lowest order and that leads to +if you like that the fact that you have + + align:start position:0% +if you like that the fact that you have + + + align:start position:0% +if you like that the fact that you have +this form and you have this projection + + align:start position:0% +this form and you have this projection + + + align:start position:0% +this form and you have this projection +relation is is kind of non-trivial even + + align:start position:0% +relation is is kind of non-trivial even + + + align:start position:0% +relation is is kind of non-trivial even +though you don't have a spin symmetry I + + align:start position:0% +though you don't have a spin symmetry I + + + align:start position:0% +though you don't have a spin symmetry I +mean there is something to it it's not + + align:start position:0% +mean there is something to it it's not + + + align:start position:0% +mean there is something to it it's not +it's not like a su2 symmetry that of the + + align:start position:0% +it's not like a su2 symmetry that of the + + + align:start position:0% +it's not like a su2 symmetry that of the +spin but it does for example when you go + + align:start position:0% +spin but it does for example when you go + + + align:start position:0% +spin but it does for example when you go +and look at form factors it does lead to + + align:start position:0% +and look at form factors it does lead to + + + align:start position:0% +and look at form factors it does lead to +non-trivial relations for those form + + align:start position:0% +non-trivial relations for those form + + + align:start position:0% +non-trivial relations for those form +factors so that I don't call it a + + align:start position:0% +factors so that I don't call it a + + + align:start position:0% +factors so that I don't call it a +symmetry I don't think of it as a + + align:start position:0% +symmetry I don't think of it as a + + + align:start position:0% +symmetry I don't think of it as a +symmetry + + align:start position:0% +symmetry + + + align:start position:0% +symmetry +but because it's not a formal group + + align:start position:0% +but because it's not a formal group + + + align:start position:0% +but because it's not a formal group +theory state of larian but I think it's + + align:start position:0% +theory state of larian but I think it's + + + align:start position:0% +theory state of larian but I think it's +basically you know well okay let me not + + align:start position:0% +basically you know well okay let me not + + + align:start position:0% +basically you know well okay let me not +speculate any + + align:start position:0% + + + + align:start position:0% + +further caus some confusion in the + + align:start position:0% +further caus some confusion in the + + + align:start position:0% +further caus some confusion in the +literature actually as + + align:start position:0% +literature actually as + + + align:start position:0% +literature actually as +well all + + align:start position:0% +well all + + + align:start position:0% +well all +right so what about gauge + + align:start position:0% +right so what about gauge + + + align:start position:0% +right so what about gauge +symmetry so we're doing a nonan gauge + + align:start position:0% +symmetry so we're doing a nonan gauge + + + align:start position:0% +symmetry so we're doing a nonan gauge +Theory the gauge + + align:start position:0% + + + + align:start position:0% + +transformation is something like this + + align:start position:0% +transformation is something like this + + + align:start position:0% +transformation is something like this +and in order to talk about gauge + + align:start position:0% +and in order to talk about gauge + + + align:start position:0% +and in order to talk about gauge +symmetry what we need to do is we need + + align:start position:0% +symmetry what we need to do is we need + + + align:start position:0% +symmetry what we need to do is we need +to talk about the gauge symmetries that + + align:start position:0% +to talk about the gauge symmetries that + + + align:start position:0% +to talk about the gauge symmetries that +are related to the two type of gluons + + align:start position:0% +are related to the two type of gluons + + + align:start position:0% +are related to the two type of gluons +that we have we have a cinear gluon we + + align:start position:0% +that we have we have a cinear gluon we + + + align:start position:0% +that we have we have a cinear gluon we +have an ultrasoft gluon you know that + + align:start position:0% +have an ultrasoft gluon you know that + + + align:start position:0% +have an ultrasoft gluon you know that +the field is acting like the connection + + align:start position:0% +the field is acting like the connection + + + align:start position:0% +the field is acting like the connection +for that gauge symmetry so there should + + align:start position:0% +for that gauge symmetry so there should + + + align:start position:0% +for that gauge symmetry so there should +be in some sense a gauge symmetry + + align:start position:0% +be in some sense a gauge symmetry + + + align:start position:0% +be in some sense a gauge symmetry +Associated to the ultrasoft gluon and a + + align:start position:0% +Associated to the ultrasoft gluon and a + + + align:start position:0% +Associated to the ultrasoft gluon and a +separate one Associated to the cinar + + align:start position:0% +separate one Associated to the cinar + + + align:start position:0% +separate one Associated to the cinar +gluon if the meaning of these things as + + align:start position:0% +gluon if the meaning of these things as + + + align:start position:0% +gluon if the meaning of these things as +gauge Fields is going to have any sense + + align:start position:0% +gauge Fields is going to have any sense + + + align:start position:0% +gauge Fields is going to have any sense +to it so rather than have just sort of + + align:start position:0% +to it so rather than have just sort of + + + align:start position:0% +to it so rather than have just sort of +this set of gauge transformation that we + + align:start position:0% +this set of gauge transformation that we + + + align:start position:0% +this set of gauge transformation that we +can make in qcd we should have some more + + align:start position:0% +can make in qcd we should have some more + + + align:start position:0% +can make in qcd we should have some more +complicated structure of gauge symmetry + + align:start position:0% +complicated structure of gauge symmetry + + + align:start position:0% +complicated structure of gauge symmetry +in the effective Theory because we have + + align:start position:0% +in the effective Theory because we have + + + align:start position:0% +in the effective Theory because we have +more complicated structure of gauge + + align:start position:0% + + + + align:start position:0% + +Fields so in order to talk about use + + align:start position:0% +Fields so in order to talk about use + + + align:start position:0% +Fields so in order to talk about use +we're going to want to divide them into + + align:start position:0% +we're going to want to divide them into + + + align:start position:0% +we're going to want to divide them into +camps and a useful thing to think about + + align:start position:0% +camps and a useful thing to think about + + + align:start position:0% +camps and a useful thing to think about +is that you want to have use that first + + align:start position:0% +is that you want to have use that first + + + align:start position:0% +is that you want to have use that first +of all leave you inside the effective + + align:start position:0% +of all leave you inside the effective + + + align:start position:0% +of all leave you inside the effective +Theory + + align:start position:0% + + + + align:start position:0% + +and really what this means is that you + + align:start position:0% +and really what this means is that you + + + align:start position:0% +and really what this means is that you +want talking about gauge symmetry to + + align:start position:0% +want talking about gauge symmetry to + + + align:start position:0% +want talking about gauge symmetry to +commute with your discussion of talking + + align:start position:0% +commute with your discussion of talking + + + align:start position:0% +commute with your discussion of talking +about power + + align:start position:0% +about power + + + align:start position:0% +about power +counting so by way of example of + + align:start position:0% +counting so by way of example of + + + align:start position:0% +counting so by way of example of +this say you had a gauge transformation + + align:start position:0% +this say you had a gauge transformation + + + align:start position:0% +this say you had a gauge transformation +that it was + + align:start position:0% + + + + align:start position:0% + +large that had made a formula like that + + align:start position:0% +large that had made a formula like that + + + align:start position:0% +large that had made a formula like that +one that I partial on it was scaling + + align:start position:0% +one that I partial on it was scaling + + + align:start position:0% +one that I partial on it was scaling +like Q okay so this would be a very + + align:start position:0% +like Q okay so this would be a very + + + align:start position:0% +like Q okay so this would be a very +large momentum Associated to that space + + align:start position:0% +large momentum Associated to that space + + + align:start position:0% +large momentum Associated to that space +time + + align:start position:0% +time + + + align:start position:0% +time +dependence then if you talked about the + + align:start position:0% +dependence then if you talked about the + + + align:start position:0% +dependence then if you talked about the +gauge transformation which would + + align:start position:0% +gauge transformation which would + + + align:start position:0% +gauge transformation which would +be U * C even if this guy has colinear + + align:start position:0% +be U * C even if this guy has colinear + + + align:start position:0% +be U * C even if this guy has colinear +momentum scaling the new guy would not + + align:start position:0% +momentum scaling the new guy would not + + + align:start position:0% +momentum scaling the new guy would not +because of this fact + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% + + + + align:start position:0% + +okay so if we want to talk about gauge + + align:start position:0% +okay so if we want to talk about gauge + + + align:start position:0% +okay so if we want to talk about gauge +symmetries we want to talk about + + align:start position:0% +symmetries we want to talk about + + + align:start position:0% +symmetries we want to talk about +symmetries that take us to the fields + + align:start position:0% +symmetries that take us to the fields + + + align:start position:0% +symmetries that take us to the fields +that we've already decided have a + + align:start position:0% +that we've already decided have a + + + align:start position:0% +that we've already decided have a +certain power counting and we don't want + + align:start position:0% +certain power counting and we don't want + + + align:start position:0% +certain power counting and we don't want +the gauge symmetry to mess that up so + + align:start position:0% +the gauge symmetry to mess that up so + + + align:start position:0% +the gauge symmetry to mess that up so +we're going to demand that that's + + align:start position:0% +we're going to demand that that's + + + align:start position:0% +we're going to demand that that's +true and then we can divide so given + + align:start position:0% +true and then we can divide so given + + + align:start position:0% +true and then we can divide so given +that we can think about dividing up the + + align:start position:0% +that we can think about dividing up the + + + align:start position:0% +that we can think about dividing up the +gauge symmetry into pieces into pieces + + align:start position:0% +gauge symmetry into pieces into pieces + + + align:start position:0% +gauge symmetry into pieces into pieces +that have different scaling in terms of + + align:start position:0% +that have different scaling in terms of + + + align:start position:0% +that have different scaling in terms of +how big the the transformation are how + + align:start position:0% +how big the the transformation are how + + + align:start position:0% +how big the the transformation are how +the how the coordinates are behaving + + align:start position:0% +the how the coordinates are behaving + + + align:start position:0% +the how the coordinates are behaving +and it's convenient to for this + + align:start position:0% +and it's convenient to for this + + + align:start position:0% +and it's convenient to for this +discussion divide them into three parts + + align:start position:0% +discussion divide them into three parts + + + align:start position:0% +discussion divide them into three parts +a global + + align:start position:0% +a global + + + align:start position:0% +a global +transformation where this guy is not + + align:start position:0% +transformation where this guy is not + + + align:start position:0% +transformation where this guy is not +space- time + + align:start position:0% +space- time + + + align:start position:0% +space- time +dependent a cinear + + align:start position:0% +dependent a cinear + + + align:start position:0% +dependent a cinear +transformation which I'll call + + align:start position:0% + + + + align:start position:0% + +UC where I partial on + + align:start position:0% +UC where I partial on + + + align:start position:0% +UC where I partial on +U scales like a cinear momentum + + align:start position:0% + + + + align:start position:0% + +and then in + + align:start position:0% + + + + align:start position:0% + +ultrasoft U + + align:start position:0% +ultrasoft U + + + align:start position:0% +ultrasoft U +us where are the I + + align:start position:0% + + + + align:start position:0% + +partial scales like an ultrasoft + + align:start position:0% + + + + align:start position:0% + +momentum and basically what we want to + + align:start position:0% +momentum and basically what we want to + + + align:start position:0% +momentum and basically what we want to +do is we want to connect this gauge + + align:start position:0% +do is we want to connect this gauge + + + align:start position:0% +do is we want to connect this gauge +transformation to the gauge field for + + align:start position:0% +transformation to the gauge field for + + + align:start position:0% +transformation to the gauge field for +the cinear and this + + align:start position:0% +the cinear and this + + + align:start position:0% +the cinear and this +transformation to the gauge field for + + align:start position:0% +transformation to the gauge field for + + + align:start position:0% +transformation to the gauge field for +the + + align:start position:0% + + + + align:start position:0% + +softs + + align:start position:0% +softs + + + align:start position:0% +softs +okay so one complication that we have to + + align:start position:0% +okay so one complication that we have to + + + align:start position:0% +okay so one complication that we have to +deal with is this momentum labels that + + align:start position:0% +deal with is this momentum labels that + + + align:start position:0% +deal with is this momentum labels that +we were talking about because the way + + align:start position:0% +we were talking about because the way + + + align:start position:0% +we were talking about because the way +that we distinguish between these types + + align:start position:0% +that we distinguish between these types + + + align:start position:0% +that we distinguish between these types +of momenta and these types of momenta + + align:start position:0% +of momenta and these types of momenta + + + align:start position:0% +of momenta and these types of momenta +was dividing things into these labels + + align:start position:0% +was dividing things into these labels + + + align:start position:0% +was dividing things into these labels +and + + align:start position:0% + + + + align:start position:0% + +residuals gauge Transformations are + + align:start position:0% +residuals gauge Transformations are + + + align:start position:0% +residuals gauge Transformations are +something that's very nice in position + + align:start position:0% +something that's very nice in position + + + align:start position:0% +something that's very nice in position +space and not so nice in momentum + + align:start position:0% + + + + align:start position:0% + +space and that's because gauge + + align:start position:0% +space and that's because gauge + + + align:start position:0% +space and that's because gauge +Transformations are local + + align:start position:0% +Transformations are local + + + align:start position:0% +Transformations are local +Transformations right and local it means + + align:start position:0% +Transformations right and local it means + + + align:start position:0% +Transformations right and local it means +local in X not in P so what is what what + + align:start position:0% +local in X not in P so what is what what + + + align:start position:0% +local in X not in P so what is what what +is simple multiplication in position + + align:start position:0% +is simple multiplication in position + + + align:start position:0% +is simple multiplication in position +space becomes convolutions in momentum + + align:start position:0% + + + + align:start position:0% + +space so if you + + align:start position:0% +space so if you + + + align:start position:0% +space so if you +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +go over to this kind of hybrid notation + + align:start position:0% +go over to this kind of hybrid notation + + + align:start position:0% +go over to this kind of hybrid notation +that we + + align:start position:0% + + + + align:start position:0% + +developed then you would have the + + align:start position:0% + + + + align:start position:0% + +following that this field if I do it + + align:start position:0% +following that this field if I do it + + + align:start position:0% +following that this field if I do it +transformation + + align:start position:0% + + + + align:start position:0% + +goes into something like that where the + + align:start position:0% +goes into something like that where the + + + align:start position:0% +goes into something like that where the +way that you should think of what this + + align:start position:0% +way that you should think of what this + + + align:start position:0% +way that you should think of what this +sum over Q is is the is in the following + + align:start position:0% + + + + align:start position:0% + +way that if you have a transformation in + + align:start position:0% +way that if you have a transformation in + + + align:start position:0% +way that if you have a transformation in +position space that looks like + + align:start position:0% +position space that looks like + + + align:start position:0% +position space that looks like +that then in momentum + + align:start position:0% +that then in momentum + + + align:start position:0% +that then in momentum +space that simple product is convolution + + align:start position:0% + + + + align:start position:0% + +okay so this is one + + align:start position:0% + + + + align:start position:0% + +dimension and you'd have that + + align:start position:0% +dimension and you'd have that + + + align:start position:0% +dimension and you'd have that +correspondence and so this kind of + + align:start position:0% +correspondence and so this kind of + + + align:start position:0% +correspondence and so this kind of +complication that we have here just + + align:start position:0% +complication that we have here just + + + align:start position:0% +complication that we have here just +corresponds to the complication that + + align:start position:0% +corresponds to the complication that + + + align:start position:0% +corresponds to the complication that +you'd have for any gauge symmetry that + + align:start position:0% +you'd have for any gauge symmetry that + + + align:start position:0% +you'd have for any gauge symmetry that +you want to write a momentum + + align:start position:0% + + + + align:start position:0% + +space but we can be slick about this and + + align:start position:0% +space but we can be slick about this and + + + align:start position:0% +space but we can be slick about this and +introduce some notation and then + + align:start position:0% +introduce some notation and then + + + align:start position:0% +introduce some notation and then +dispense with it because it's really not + + align:start position:0% +dispense with it because it's really not + + + align:start position:0% +dispense with it because it's really not +a technical complication it's just an + + align:start position:0% +a technical complication it's just an + + + align:start position:0% +a technical complication it's just an +ational + + align:start position:0% +ational + + + align:start position:0% +ational +complication so let's do that in the + + align:start position:0% +complication so let's do that in the + + + align:start position:0% +complication so let's do that in the +following + + align:start position:0% +following + + + align:start position:0% +following +way let's let UC + + align:start position:0% +way let's let UC + + + align:start position:0% +way let's let UC +see which is a + + align:start position:0% +see which is a + + + align:start position:0% +see which is a +matrix with two + + align:start position:0% + + + + align:start position:0% + +indices be + + align:start position:0% +indices be + + + align:start position:0% +indices be +defined by this + + align:start position:0% +defined by this + + + align:start position:0% +defined by this +UC of PL minus + + align:start position:0% + + + + align:start position:0% + +ql so say Define a matrix + + align:start position:0% +ql so say Define a matrix + + + align:start position:0% +ql so say Define a matrix +then we can use a matrix notation for + + align:start position:0% +then we can use a matrix notation for + + + align:start position:0% +then we can use a matrix notation for +the + + align:start position:0% +the + + + align:start position:0% +the +convolutions where we sum over repeated + + align:start position:0% +convolutions where we sum over repeated + + + align:start position:0% +convolutions where we sum over repeated +indices and that takes care of this + + align:start position:0% +indices and that takes care of this + + + align:start position:0% +indices and that takes care of this +notational + + align:start position:0% + + + + align:start position:0% + +complication so the peak what what is + + align:start position:0% +complication so the peak what what is + + + align:start position:0% +complication so the peak what what is +meant by this is that the pl ql entry of + + align:start position:0% +meant by this is that the pl ql entry of + + + align:start position:0% +meant by this is that the pl ql entry of +this + + align:start position:0% +this + + + align:start position:0% +this +Matrix is a number and that number is + + align:start position:0% +Matrix is a number and that number is + + + align:start position:0% +Matrix is a number and that number is +given by this thing that we call + + align:start position:0% +given by this thing that we call + + + align:start position:0% +given by this thing that we call +UC PL minus ql + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% + + + + align:start position:0% + +okay so then the formula up here could + + align:start position:0% +okay so then the formula up here could + + + align:start position:0% +okay so then the formula up here could +just be written turns that Matrix as a + + align:start position:0% +just be written turns that Matrix as a + + + align:start position:0% +just be written turns that Matrix as a +kind of matrix + + align:start position:0% + + + + align:start position:0% + +multiplication okay so what are the + + align:start position:0% +multiplication okay so what are the + + + align:start position:0% +multiplication okay so what are the +Transformations if once we adopt + + align:start position:0% + + + + align:start position:0% + +that let me write them down and then + + align:start position:0% +that let me write them down and then + + + align:start position:0% +that let me write them down and then +talk about them + + align:start position:0% + + + + align:start position:0% + +so CN of X goes to U of X CN of X where + + align:start position:0% +so CN of X goes to U of X CN of X where + + + align:start position:0% +so CN of X goes to U of X CN of X where +you should understand this thing as a + + align:start position:0% +you should understand this thing as a + + + align:start position:0% +you should understand this thing as a +matrix that has two indices like + + align:start position:0% +matrix that has two indices like + + + align:start position:0% +matrix that has two indices like +this also depending on space + + align:start position:0% +this also depending on space + + + align:start position:0% +this also depending on space +time and I just dot over the repeated + + align:start position:0% +time and I just dot over the repeated + + + align:start position:0% +time and I just dot over the repeated +indices in this thing which is like a + + align:start position:0% +indices in this thing which is like a + + + align:start position:0% +indices in this thing which is like a +vector so this is like a + + align:start position:0% +vector so this is like a + + + align:start position:0% +vector so this is like a +matrix and this is + + align:start position:0% + + + + align:start position:0% + +Vector that makes it look like it's the + + align:start position:0% +Vector that makes it look like it's the + + + align:start position:0% +Vector that makes it look like it's the +usual kind of notation which was the + + align:start position:0% +usual kind of notation which was the + + + align:start position:0% +usual kind of notation which was the +point introducing this + + align:start position:0% + + + + align:start position:0% + +notation so for the colinear gaug guge + + align:start position:0% +notation so for the colinear gaug guge + + + align:start position:0% +notation so for the colinear gaug guge +field it's going to be basically that it + + align:start position:0% +field it's going to be basically that it + + + align:start position:0% +field it's going to be basically that it +as as we said over here that it's + + align:start position:0% +as as we said over here that it's + + + align:start position:0% +as as we said over here that it's +becomes the gauge field of that + + align:start position:0% +becomes the gauge field of that + + + align:start position:0% +becomes the gauge field of that +transformation and so that's what this + + align:start position:0% +transformation and so that's what this + + + align:start position:0% +transformation and so that's what this +would be that would be the standard + + align:start position:0% +would be that would be the standard + + + align:start position:0% +would be that would be the standard +gauge transformation and then there's + + align:start position:0% +gauge transformation and then there's + + + align:start position:0% +gauge transformation and then there's +one little complication here which is I + + align:start position:0% +one little complication here which is I + + + align:start position:0% +one little complication here which is I +wrote curly de ultrasoft the ultrasoft + + align:start position:0% +wrote curly de ultrasoft the ultrasoft + + + align:start position:0% +wrote curly de ultrasoft the ultrasoft +derivative the thing that has the N.A + + align:start position:0% +derivative the thing that has the N.A + + + align:start position:0% +derivative the thing that has the N.A +ultrasoft field in + + align:start position:0% + + + + align:start position:0% + +it so the reason that I wanted to do + + align:start position:0% +it so the reason that I wanted to do + + + align:start position:0% +it so the reason that I wanted to do +that is because I'm thinking here of the + + align:start position:0% +that is because I'm thinking here of the + + + align:start position:0% +that is because I'm thinking here of the +ultrasoft field when I'm thinking about + + align:start position:0% +ultrasoft field when I'm thinking about + + + align:start position:0% +ultrasoft field when I'm thinking about +cinear Fields I'm thinking of the + + align:start position:0% +cinear Fields I'm thinking of the + + + align:start position:0% +cinear Fields I'm thinking of the +ultrasoft field as a background field + + align:start position:0% +ultrasoft field as a background field + + + align:start position:0% +ultrasoft field as a background field +and if I was to do a background field + + align:start position:0% +and if I was to do a background field + + + align:start position:0% +and if I was to do a background field +gauge transformation then I would have a + + align:start position:0% +gauge transformation then I would have a + + + align:start position:0% +gauge transformation then I would have a +coant derivative here under the + + align:start position:0% + + + + align:start position:0% + +background so this n. a ultrasoft is + + align:start position:0% +background so this n. a ultrasoft is + + + align:start position:0% +background so this n. a ultrasoft is +like a background field to the cinear + + align:start position:0% +like a background field to the cinear + + + align:start position:0% +like a background field to the cinear +gauge + + align:start position:0% + + + + align:start position:0% + +field so + + align:start position:0% + + + + align:start position:0% + +this if you want to make an analogy of + + align:start position:0% +this if you want to make an analogy of + + + align:start position:0% +this if you want to make an analogy of +what this is + + align:start position:0% + + + + align:start position:0% + +like it's like the quantum gauge + + align:start position:0% +like it's like the quantum gauge + + + align:start position:0% +like it's like the quantum gauge +transformation of a field that has a + + align:start position:0% +transformation of a field that has a + + + align:start position:0% +transformation of a field that has a +background + + align:start position:0% + + + + align:start position:0% + +so if you look up how background field + + align:start position:0% +so if you look up how background field + + + align:start position:0% +so if you look up how background field +gauge works and background field + + align:start position:0% +gauge works and background field + + + align:start position:0% +gauge works and background field +Transformations that's how you'd have + + align:start position:0% +Transformations that's how you'd have + + + align:start position:0% +Transformations that's how you'd have +the same thing you'd have something + + align:start position:0% +the same thing you'd have something + + + align:start position:0% +the same thing you'd have something +covariant under the background and + + align:start position:0% +covariant under the background and + + + align:start position:0% +covariant under the background and +that's what we're going to do here as + + align:start position:0% +that's what we're going to do here as + + + align:start position:0% +that's what we're going to do here as +well yep kind of Sil question so UC of X + + align:start position:0% +well yep kind of Sil question so UC of X + + + align:start position:0% +well yep kind of Sil question so UC of X +is a matrix mhm so what exactly UC p + + align:start position:0% +is a matrix mhm so what exactly UC p + + + align:start position:0% +is a matrix mhm so what exactly UC p +that should be right well no this is + + align:start position:0% +that should be right well no this is + + + align:start position:0% +that should be right well no this is +just a number so these have some this is + + align:start position:0% +just a number so these have some this is + + + align:start position:0% +just a number so these have some this is +just think of this as like you know this + + align:start position:0% +just think of this as like you know this + + + align:start position:0% +just think of this as like you know this +is some Vector this is some other Vector + + align:start position:0% +is some Vector this is some other Vector + + + align:start position:0% +is some Vector this is some other Vector +the difference of these is some label on + + align:start position:0% +the difference of these is some label on + + + align:start position:0% +the difference of these is some label on +this thing right and for each value of + + align:start position:0% +this thing right and for each value of + + + align:start position:0% +this thing right and for each value of +this I get a different number and know + + align:start position:0% +this I get a different number and know + + + align:start position:0% +this I get a different number and know +for each value of space time I get a + + align:start position:0% +for each value of space time I get a + + + align:start position:0% +for each value of space time I get a +different number but this thing is just + + align:start position:0% +different number but this thing is just + + + align:start position:0% +different number but this thing is just +a number and I'm saying think of it like + + align:start position:0% +a number and I'm saying think of it like + + + align:start position:0% +a number and I'm saying think of it like +a matrix in the sense of because we're + + align:start position:0% +a matrix in the sense of because we're + + + align:start position:0% +a matrix in the sense of because we're +thinking of these as + + align:start position:0% +thinking of these as + + + align:start position:0% +thinking of these as +discret but right UC has + + align:start position:0% +discret but right UC has + + + align:start position:0% +discret but right UC has +oh yeah yeah yeah that's another matrix + + align:start position:0% +oh yeah yeah yeah that's another matrix + + + align:start position:0% +oh yeah yeah yeah that's another matrix +it's an orthogonal matrix it's also a + + align:start position:0% +it's an orthogonal matrix it's also a + + + align:start position:0% +it's an orthogonal matrix it's also a +matrix in that space yeah yeah yeah so + + align:start position:0% +matrix in that space yeah yeah yeah so + + + align:start position:0% +matrix in that space yeah yeah yeah so +here it's a matrix I'm defining a matrix + + align:start position:0% +here it's a matrix I'm defining a matrix + + + align:start position:0% +here it's a matrix I'm defining a matrix +in a new space which is this momentum + + align:start position:0% +in a new space which is this momentum + + + align:start position:0% +in a new space which is this momentum +space and that's just really my way of + + align:start position:0% +space and that's just really my way of + + + align:start position:0% +space and that's just really my way of +making transformations in momentum space + + align:start position:0% +making transformations in momentum space + + + align:start position:0% +making transformations in momentum space +look like as simple as simple as they do + + align:start position:0% +look like as simple as simple as they do + + + align:start position:0% +look like as simple as simple as they do +in position Space by just having sort of + + align:start position:0% +in position Space by just having sort of + + + align:start position:0% +in position Space by just having sort of +a matrix notation for the + + align:start position:0% +a matrix notation for the + + + align:start position:0% +a matrix notation for the +convolutions so that number is + + align:start position:0% +convolutions so that number is + + + align:start position:0% +convolutions so that number is +essentially a matrix it's a matrix yeah + + align:start position:0% +essentially a matrix it's a matrix yeah + + + align:start position:0% +essentially a matrix it's a matrix yeah +in that space good point + + align:start position:0% + + + + align:start position:0% + +what about the ultrasoft + + align:start position:0% +what about the ultrasoft + + + align:start position:0% +what about the ultrasoft +fields well ultrasoft Fields shouldn't + + align:start position:0% +fields well ultrasoft Fields shouldn't + + + align:start position:0% +fields well ultrasoft Fields shouldn't +transform under colinear gauge + + align:start position:0% +transform under colinear gauge + + + align:start position:0% +transform under colinear gauge +Transformations because of the exactly + + align:start position:0% +Transformations because of the exactly + + + align:start position:0% +Transformations because of the exactly +the same logic that I gave you a minute + + align:start position:0% +the same logic that I gave you a minute + + + align:start position:0% +the same logic that I gave you a minute +ago about why I shouldn't be able to + + align:start position:0% +ago about why I shouldn't be able to + + + align:start position:0% +ago about why I shouldn't be able to +inject a hard momentum like this one + + align:start position:0% +inject a hard momentum like this one + + + align:start position:0% +inject a hard momentum like this one +into into the effective theory if I want + + align:start position:0% +into into the effective theory if I want + + + align:start position:0% +into into the effective theory if I want +my ultrasoft fields to remain Ultra + + align:start position:0% +my ultrasoft fields to remain Ultra + + + align:start position:0% +my ultrasoft fields to remain Ultra +Soft then I can't let them transform + + align:start position:0% +Soft then I can't let them transform + + + align:start position:0% +Soft then I can't let them transform +because that would spoil their power + + align:start position:0% +because that would spoil their power + + + align:start position:0% +because that would spoil their power +Counting + + align:start position:0% + + + + align:start position:0% + +so Q + + align:start position:0% +so Q + + + align:start position:0% +so Q +ultrasoft under this UC + + align:start position:0% +ultrasoft under this UC + + + align:start position:0% +ultrasoft under this UC +transformation just goes to Q ultr + + align:start position:0% +transformation just goes to Q ultr + + + align:start position:0% +transformation just goes to Q ultr +soft and a + + align:start position:0% +soft and a + + + align:start position:0% +soft and a +ultrasoft has to go to a + + align:start position:0% +ultrasoft has to go to a + + + align:start position:0% +ultrasoft has to go to a +ultrasoft so these things should not be + + align:start position:0% +ultrasoft so these things should not be + + + align:start position:0% +ultrasoft so these things should not be +touched by that transformation why can I + + align:start position:0% +touched by that transformation why can I + + + align:start position:0% +touched by that transformation why can I +mean make the ultt ultt and through well + + align:start position:0% +mean make the ultt ultt and through well + + + align:start position:0% +mean make the ultt ultt and through well +we don't want that you could think of + + align:start position:0% +we don't want that you could think of + + + align:start position:0% +we don't want that you could think of +trying to De develop effective Theory + + align:start position:0% +trying to De develop effective Theory + + + align:start position:0% +trying to De develop effective Theory +where they would mix right but whenever + + align:start position:0% +where they would mix right but whenever + + + align:start position:0% +where they would mix right but whenever +you have a lran that mixes two Fields + + align:start position:0% +you have a lran that mixes two Fields + + + align:start position:0% +you have a lran that mixes two Fields +the first thing you try to do is to + + align:start position:0% +the first thing you try to do is to + + + align:start position:0% +the first thing you try to do is to +force them not to mix so it's better you + + align:start position:0% +force them not to mix so it's better you + + + align:start position:0% +force them not to mix so it's better you +know yeah say I set the theory up so + + align:start position:0% +know yeah say I set the theory up so + + + align:start position:0% +know yeah say I set the theory up so +that they mixed the first thing I would + + align:start position:0% +that they mixed the first thing I would + + + align:start position:0% +that they mixed the first thing I would +try to do that lran is make field + + align:start position:0% +try to do that lran is make field + + + align:start position:0% +try to do that lran is make field +redefinitions to go to some set form of + + align:start position:0% +redefinitions to go to some set form of + + + align:start position:0% +redefinitions to go to some set form of +the lran that wouldn't mix okay so I + + align:start position:0% +the lran that wouldn't mix okay so I + + + align:start position:0% +the lran that wouldn't mix okay so I +prefer if you like to to develop you + + align:start position:0% +prefer if you like to to develop you + + + align:start position:0% +prefer if you like to to develop you +know the one that doesn't mix right from + + align:start position:0% +know the one that doesn't mix right from + + + align:start position:0% +know the one that doesn't mix right from +the start and you could view it that + + align:start position:0% +the start and you could view it that + + + align:start position:0% +the start and you could view it that +way so you know you could always think + + align:start position:0% +way so you know you could always think + + + align:start position:0% +way so you know you could always think +of I'm going to tell you likes two sets + + align:start position:0% +of I'm going to tell you likes two sets + + + align:start position:0% +of I'm going to tell you likes two sets +of Transformations you could always + + align:start position:0% +of Transformations you could always + + + align:start position:0% +of Transformations you could always +think of formulating linear combinations + + align:start position:0% +think of formulating linear combinations + + + align:start position:0% +think of formulating linear combinations +of those Transformations say these are + + align:start position:0% +of those Transformations say these are + + + align:start position:0% +of those Transformations say these are +the fundamental ones not the ones you + + align:start position:0% +the fundamental ones not the ones you + + + align:start position:0% +the fundamental ones not the ones you +wrote down but these other ones right + + align:start position:0% +wrote down but these other ones right + + + align:start position:0% +wrote down but these other ones right +and then you know by some manipulations + + align:start position:0% +and then you know by some manipulations + + + align:start position:0% +and then you know by some manipulations +one could go to the ones I'm talking + + align:start position:0% +one could go to the ones I'm talking + + + align:start position:0% +one could go to the ones I'm talking +about + + align:start position:0% + + + + align:start position:0% + +all + + align:start position:0% + + + + align:start position:0% + +right so now the other set of + + align:start position:0% +right so now the other set of + + + align:start position:0% +right so now the other set of +Transformations that we + + align:start position:0% +Transformations that we + + + align:start position:0% +Transformations that we +want are these ultrasoft ones and for + + align:start position:0% +want are these ultrasoft ones and for + + + align:start position:0% +want are these ultrasoft ones and for +those for that type of trans + + align:start position:0% +those for that type of trans + + + align:start position:0% +those for that type of trans +transformation we don't have this same + + align:start position:0% +transformation we don't have this same + + + align:start position:0% +transformation we don't have this same +type of problem with the cinear we don't + + align:start position:0% +type of problem with the cinear we don't + + + align:start position:0% +type of problem with the cinear we don't +we can't say the cinear fields don't + + align:start position:0% +we can't say the cinear fields don't + + + align:start position:0% +we can't say the cinear fields don't +transform because that type of + + align:start position:0% +transform because that type of + + + align:start position:0% +transform because that type of +transformation it doesn't spoil the + + align:start position:0% +transformation it doesn't spoil the + + + align:start position:0% +transformation it doesn't spoil the +cinear field being cinear we can always + + align:start position:0% +cinear field being cinear we can always + + + align:start position:0% +cinear field being cinear we can always +add ultrasoft momentum to + + align:start position:0% +add ultrasoft momentum to + + + align:start position:0% +add ultrasoft momentum to +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +it so these fields CN and a an will + + align:start position:0% +it so these fields CN and a an will + + + align:start position:0% +it so these fields CN and a an will +transform like background + + align:start position:0% +transform like background + + + align:start position:0% +transform like background +Fields sorry like Quantum fields in a + + align:start position:0% +Fields sorry like Quantum fields in a + + + align:start position:0% +Fields sorry like Quantum fields in a +background + + align:start position:0% + + + + align:start position:0% + +so from the point of view of the CN + + align:start position:0% +so from the point of view of the CN + + + align:start position:0% +so from the point of view of the CN +fields which are the shorter distance + + align:start position:0% +fields which are the shorter distance + + + align:start position:0% +fields which are the shorter distance +Fields you can really think of like what + + align:start position:0% +Fields you can really think of like what + + + align:start position:0% +Fields you can really think of like what +we're doing here is exactly like what + + align:start position:0% +we're doing here is exactly like what + + + align:start position:0% +we're doing here is exactly like what +you would do if you had Quantum and + + align:start position:0% +you would do if you had Quantum and + + + align:start position:0% +you would do if you had Quantum and +background gauge + + align:start position:0% + + + + align:start position:0% + +Transformations and the physics of + + align:start position:0% +Transformations and the physics of + + + align:start position:0% +Transformations and the physics of +thinking of the background is a longer + + align:start position:0% +thinking of the background is a longer + + + align:start position:0% +thinking of the background is a longer +wavelength mode is exactly the right way + + align:start position:0% +wavelength mode is exactly the right way + + + align:start position:0% +wavelength mode is exactly the right way +of thinking about how these fields which + + align:start position:0% +of thinking about how these fields which + + + align:start position:0% +of thinking about how these fields which +are shorter w length think about the + + align:start position:0% +are shorter w length think about the + + + align:start position:0% +are shorter w length think about the +ultrasoft + + align:start position:0% + + + + align:start position:0% + +fields so what that means is that they + + align:start position:0% +fields so what that means is that they + + + align:start position:0% +fields so what that means is that they +transform like matter fields in the + + align:start position:0% +transform like matter fields in the + + + align:start position:0% +transform like matter fields in the +appropriate + + align:start position:0% +appropriate + + + align:start position:0% +appropriate +[Applause] + + align:start position:0% + + + + align:start position:0% + +representation okay so with that in hand + + align:start position:0% +representation okay so with that in hand + + + align:start position:0% +representation okay so with that in hand +then we can write down how things + + align:start position:0% +then we can write down how things + + + align:start position:0% +then we can write down how things +transform under the + + align:start position:0% + + + + align:start position:0% + +ultrasofts a fion just transforms like + + align:start position:0% +ultrasofts a fion just transforms like + + + align:start position:0% +ultrasofts a fion just transforms like +that on the left and this unlike our + + align:start position:0% +that on the left and this unlike our + + + align:start position:0% +that on the left and this unlike our +notation over there this is one number + + align:start position:0% +notation over there this is one number + + + align:start position:0% +notation over there this is one number +for all entries in the + + align:start position:0% + + + + align:start position:0% + +vector this guy doesn't have any indices + + align:start position:0% + + + + align:start position:0% + +okay so this is like transforming all + + align:start position:0% +okay so this is like transforming all + + + align:start position:0% +okay so this is like transforming all +the terms in the vector by the same + + align:start position:0% +the terms in the vector by the same + + + align:start position:0% +the terms in the vector by the same +overall Matrix overall color Matrix + + align:start position:0% +overall Matrix overall color Matrix + + + align:start position:0% +overall Matrix overall color Matrix +overall number in in the in the momentum + + align:start position:0% +overall number in in the in the momentum + + + align:start position:0% +overall number in in the in the momentum +Matrix + + align:start position:0% + + + + align:start position:0% + +space so this guy should transform like + + align:start position:0% +space so this guy should transform like + + + align:start position:0% +space so this guy should transform like +an + + align:start position:0% +an + + + align:start position:0% +an +adjoint and you can write the adjoint as + + align:start position:0% +adjoint and you can write the adjoint as + + + align:start position:0% +adjoint and you can write the adjoint as +a u each + + align:start position:0% +a u each + + + align:start position:0% +a u each +side so there's kind of two ways of + + align:start position:0% +side so there's kind of two ways of + + + align:start position:0% +side so there's kind of two ways of +writing the transformation here you + + align:start position:0% +writing the transformation here you + + + align:start position:0% +writing the transformation here you +could write it + + align:start position:0% +could write it + + + align:start position:0% +could write it +as like + + align:start position:0% +as like + + + align:start position:0% +as like +this if you wrote down an adjoint + + align:start position:0% +this if you wrote down an adjoint + + + align:start position:0% +this if you wrote down an adjoint +transformation then this guy would have + + align:start position:0% +transformation then this guy would have + + + align:start position:0% +transformation then this guy would have +two indices A and + + align:start position:0% + + + + align:start position:0% + +B and you'd have a transformation like + + align:start position:0% +B and you'd have a transformation like + + + align:start position:0% +B and you'd have a transformation like +that where this is an ad in the ad joint + + align:start position:0% +that where this is an ad in the ad joint + + + align:start position:0% +that where this is an ad in the ad joint +but if you want to write it in terms of + + align:start position:0% +but if you want to write it in terms of + + + align:start position:0% +but if you want to write it in terms of +the U ultrasoft that's e to the it which + + align:start position:0% +the U ultrasoft that's e to the it which + + + align:start position:0% +the U ultrasoft that's e to the it which +is in the fund fundamental then you + + align:start position:0% +is in the fund fundamental then you + + + align:start position:0% +is in the fund fundamental then you +write it like this + + align:start position:0% +write it like this + + + align:start position:0% +write it like this +and those are + + align:start position:0% + + + + align:start position:0% + +equivalent so why are they + + align:start position:0% +equivalent so why are they + + + align:start position:0% +equivalent so why are they +equivalent so they're equivalent because + + align:start position:0% +equivalent so they're equivalent because + + + align:start position:0% +equivalent so they're equivalent because +well okay maybe I'll tell you + + align:start position:0% +well okay maybe I'll tell you + + + align:start position:0% +well okay maybe I'll tell you +later yeah um I + + align:start position:0% +later yeah um I + + + align:start position:0% +later yeah um I +um I'm always confused about why + + align:start position:0% +um I'm always confused about why + + + align:start position:0% +um I'm always confused about why +n. is a background field um to a + + align:start position:0% +n. is a background field um to a + + + align:start position:0% +n. is a background field um to a +ultrasoft um it actually has the same + + align:start position:0% +ultrasoft um it actually has the same + + + align:start position:0% +ultrasoft um it actually has the same +size momentum so wavelength is the same + + align:start position:0% +size momentum so wavelength is the same + + + align:start position:0% +size momentum so wavelength is the same +size the wavelength is not the same size + + align:start position:0% +size the wavelength is not the same size + + + align:start position:0% +size the wavelength is not the same size +the component is the same the component + + align:start position:0% +the component is the same the component + + + align:start position:0% +the component is the same the component +power counting is the same size but the + + align:start position:0% +power counting is the same size but the + + + align:start position:0% +power counting is the same size but the +n. field carries momentum which have p^ + + align:start position:0% +n. field carries momentum which have p^ + + + align:start position:0% +n. field carries momentum which have p^ +squ which is much larger right P squ do + + align:start position:0% +squ which is much larger right P squ do + + + align:start position:0% +squ which is much larger right P squ do +the wavelength so I'm talking about the + + align:start position:0% +the wavelength so I'm talking about the + + + align:start position:0% +the wavelength so I'm talking about the +wavelength which is related to that P + + align:start position:0% +wavelength which is related to that P + + + align:start position:0% +wavelength which is related to that P +squ so you think about the n.n field + + align:start position:0% +squ so you think about the n.n field + + + align:start position:0% +squ so you think about the n.n field +carries a large P minus momentum still + + align:start position:0% +carries a large P minus momentum still + + + align:start position:0% +carries a large P minus momentum still +right even though it has a + + align:start position:0% +right even though it has a + + + align:start position:0% +right even though it has a +small it it carries in order one p minus + + align:start position:0% +small it it carries in order one p minus + + + align:start position:0% +small it it carries in order one p minus +momentum so just if it's confusing think + + align:start position:0% +momentum so just if it's confusing think + + + align:start position:0% +momentum so just if it's confusing think +about just the P minus momentum the n. + + align:start position:0% +about just the P minus momentum the n. + + + align:start position:0% +about just the P minus momentum the n. +field right has P minus which is a water + + align:start position:0% +field right has P minus which is a water + + + align:start position:0% +field right has P minus which is a water +Lambda the + + align:start position:0% +Lambda the + + + align:start position:0% +Lambda the +zero so just let's think about + + align:start position:0% +zero so just let's think about + + + align:start position:0% +zero so just let's think about +wavelength with respect to P minus + + align:start position:0% +wavelength with respect to P minus + + + align:start position:0% +wavelength with respect to P minus +that's definitely true right whereas the + + align:start position:0% +that's definitely true right whereas the + + + align:start position:0% +that's definitely true right whereas the +N.A ultrasoft + + align:start position:0% +N.A ultrasoft + + + align:start position:0% +N.A ultrasoft +field carries P minus which is water + + align:start position:0% +field carries P minus which is water + + + align:start position:0% +field carries P minus which is water +Lambda squar so just just thinking about + + align:start position:0% +Lambda squar so just just thinking about + + + align:start position:0% +Lambda squar so just just thinking about +those two say + + align:start position:0% +those two say + + + align:start position:0% +those two say +the moment component thei yeah + + align:start position:0% + + + + align:start position:0% + +yeah all right I have room here to + + align:start position:0% +yeah all right I have room here to + + + align:start position:0% +yeah all right I have room here to +squeeze final transformation so the the + + align:start position:0% +squeeze final transformation so the the + + + align:start position:0% +squeeze final transformation so the the +final Transformations are just what + + align:start position:0% +final Transformations are just what + + + align:start position:0% +final Transformations are just what +you'd expect that the ultrasoft fields + + align:start position:0% +you'd expect that the ultrasoft fields + + + align:start position:0% +you'd expect that the ultrasoft fields +transform as ultrasoft as regular gauge + + align:start position:0% +transform as ultrasoft as regular gauge + + + align:start position:0% +transform as ultrasoft as regular gauge +Fields so let me just squeeze that in + + align:start position:0% + + + + align:start position:0% + +all right so there's the regular + + align:start position:0% +all right so there's the regular + + + align:start position:0% +all right so there's the regular +Transformations that you'd have for a + + align:start position:0% +Transformations that you'd have for a + + + align:start position:0% +Transformations that you'd have for a +gauge + + align:start position:0% +gauge + + + align:start position:0% +gauge +field yeah so + + align:start position:0% +field yeah so + + + align:start position:0% +field yeah so +um I just want to clarify these two uh + + align:start position:0% +um I just want to clarify these two uh + + + align:start position:0% +um I just want to clarify these two uh +these two analogies to background + + align:start position:0% +these two analogies to background + + + align:start position:0% +these two analogies to background +transformation they are not disconnected + + align:start position:0% +transformation they are not disconnected + + + align:start position:0% +transformation they are not disconnected +right they're not disconnected in the + + align:start position:0% +right they're not disconnected in the + + + align:start position:0% +right they're not disconnected in the +sense that's right yeah so if you if you + + align:start position:0% +sense that's right yeah so if you if you + + + align:start position:0% +sense that's right yeah so if you if you +take the background field notation and + + align:start position:0% +take the background field notation and + + + align:start position:0% +take the background field notation and +you just really think about that then + + align:start position:0% +you just really think about that then + + + align:start position:0% +you just really think about that then +that's this is how you would transform + + align:start position:0% +that's this is how you would transform + + + align:start position:0% +that's this is how you would transform +the quantum field under the background + + align:start position:0% +the quantum field under the background + + + align:start position:0% +the quantum field under the background +gauge + + align:start position:0% +gauge + + + align:start position:0% +gauge +transformation and this is how you would + + align:start position:0% +transformation and this is how you would + + + align:start position:0% +transformation and this is how you would +transform the qu the quantum field under + + align:start position:0% +transform the qu the quantum field under + + + align:start position:0% +transform the qu the quantum field under +the quantum gaug transation yeah that's + + align:start position:0% +the quantum gaug transation yeah that's + + + align:start position:0% +the quantum gaug transation yeah that's +right yeah so even if you made this two + + align:start position:0% +right yeah so even if you made this two + + + align:start position:0% +right yeah so even if you made this two +separate guge transformation for they + + align:start position:0% +separate guge transformation for they + + + align:start position:0% +separate guge transformation for they +still have the same one numbers yeah + + align:start position:0% +still have the same one numbers yeah + + + align:start position:0% +still have the same one numbers yeah +that's right are they going to mix at + + align:start position:0% +that's right are they going to mix at + + + align:start position:0% +that's right are they going to mix at +some Loop level um we're going to make + + align:start position:0% +some Loop level um we're going to make + + + align:start position:0% +some Loop level um we're going to make +sure they don't + + align:start position:0% +sure they don't + + + align:start position:0% +sure they don't +okay yeah I mean in some sense we really + + align:start position:0% +okay yeah I mean in some sense we really + + + align:start position:0% +okay yeah I mean in some sense we really +want you know the picture is this one + + align:start position:0% +want you know the picture is this one + + + align:start position:0% +want you know the picture is this one +that we had + + align:start position:0% +that we had + + + align:start position:0% +that we had +earlier where we really want the cinear + + align:start position:0% +earlier where we really want the cinear + + + align:start position:0% +earlier where we really want the cinear +fields to live up + + align:start position:0% +fields to live up + + + align:start position:0% +fields to live up +here so we had these hyperbolas right we + + align:start position:0% +here so we had these hyperbolas right we + + + align:start position:0% +here so we had these hyperbolas right we +want this guy to live up here and this + + align:start position:0% +want this guy to live up here and this + + + align:start position:0% +want this guy to live up here and this +guy to live up down + + align:start position:0% +guy to live up down + + + align:start position:0% +guy to live up down +there in momentum space so this was P + + align:start position:0% +there in momentum space so this was P + + + align:start position:0% +there in momentum space so this was P +minus this is p+ so we want them to live + + align:start position:0% +minus this is p+ so we want them to live + + + align:start position:0% +minus this is p+ so we want them to live +in different places they have the same + + align:start position:0% +in different places they have the same + + + align:start position:0% +in different places they have the same +Quant quantum numbers except we want + + align:start position:0% +Quant quantum numbers except we want + + + align:start position:0% +Quant quantum numbers except we want +them in momentum space to live in + + align:start position:0% +them in momentum space to live in + + + align:start position:0% +them in momentum space to live in +different places and to describe + + align:start position:0% +different places and to describe + + + align:start position:0% +different places and to describe +different degrees of + + align:start position:0% +different degrees of + + + align:start position:0% +different degrees of +freedom right so everything that we did + + align:start position:0% +freedom right so everything that we did + + + align:start position:0% +freedom right so everything that we did +here is exactly related to this picture + + align:start position:0% +here is exactly related to this picture + + + align:start position:0% +here is exactly related to this picture +that we want to talk about this guy is + + align:start position:0% +that we want to talk about this guy is + + + align:start position:0% +that we want to talk about this guy is +having larger momentum talk about gauge + + align:start position:0% +having larger momentum talk about gauge + + + align:start position:0% +having larger momentum talk about gauge +Transformations that kind of Shuffle + + align:start position:0% +Transformations that kind of Shuffle + + + align:start position:0% +Transformations that kind of Shuffle +things around with components that have + + align:start position:0% +things around with components that have + + + align:start position:0% +things around with components that have +large momentum versus small momentum + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% + + + + align:start position:0% + +all + + align:start position:0% +all + + + align:start position:0% +all +right so we're going to hypothesize that + + align:start position:0% +right so we're going to hypothesize that + + + align:start position:0% +right so we're going to hypothesize that +these gauge Transformations are the + + align:start position:0% +these gauge Transformations are the + + + align:start position:0% +these gauge Transformations are the +fundamental symmetry of the effective + + align:start position:0% + + + + align:start position:0% + +Theory and I Tred to motivate fate them + + align:start position:0% +Theory and I Tred to motivate fate them + + + align:start position:0% +Theory and I Tred to motivate fate them +physically by this analogy with + + align:start position:0% +physically by this analogy with + + + align:start position:0% +physically by this analogy with +background field gauge and thinking + + align:start position:0% +background field gauge and thinking + + + align:start position:0% +background field gauge and thinking +about a longer wavelength mode with + + align:start position:0% +about a longer wavelength mode with + + + align:start position:0% +about a longer wavelength mode with +respect to a shorter wavelength mode + + align:start position:0% +respect to a shorter wavelength mode + + + align:start position:0% +respect to a shorter wavelength mode +which is in this picture exactly the + + align:start position:0% +which is in this picture exactly the + + + align:start position:0% +which is in this picture exactly the +fact that this hyperbola is higher than + + align:start position:0% +fact that this hyperbola is higher than + + + align:start position:0% +fact that this hyperbola is higher than +this + + align:start position:0% +this + + + align:start position:0% +this +one maybe the hyperbola should stay on + + align:start position:0% +one maybe the hyperbola should stay on + + + align:start position:0% +one maybe the hyperbola should stay on +the + + align:start position:0% +the + + + align:start position:0% +the +board okay so the kind of multipole or + + align:start position:0% +board okay so the kind of multipole or + + + align:start position:0% +board okay so the kind of multipole or +the the multipole expansion that we did + + align:start position:0% +the the multipole expansion that we did + + + align:start position:0% +the the multipole expansion that we did +between these fields and the sort of + + align:start position:0% +between these fields and the sort of + + + align:start position:0% +between these fields and the sort of +thing that the statement that this is a + + align:start position:0% +thing that the statement that this is a + + + align:start position:0% +thing that the statement that this is a +longer wavelength + + align:start position:0% +longer wavelength + + + align:start position:0% +longer wavelength +mode is exactly the fact that there's a + + align:start position:0% +mode is exactly the fact that there's a + + + align:start position:0% +mode is exactly the fact that there's a +separation between these guys + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +so we'll take these to be the + + align:start position:0% +so we'll take these to be the + + + align:start position:0% +so we'll take these to be the +fundamental + + align:start position:0% + + + + align:start position:0% + +Transformations that do not get + + align:start position:0% +Transformations that do not get + + + align:start position:0% +Transformations that do not get +corrected by power + + align:start position:0% + + + + align:start position:0% + +Corrections and I'm not claiming that + + align:start position:0% +Corrections and I'm not claiming that + + + align:start position:0% +Corrections and I'm not claiming that +that's necessarily unique way of getting + + align:start position:0% +that's necessarily unique way of getting + + + align:start position:0% +that's necessarily unique way of getting +to the effective Theory you could think + + align:start position:0% +to the effective Theory you could think + + + align:start position:0% +to the effective Theory you could think +of + + align:start position:0% +of + + + align:start position:0% +of +I there might be example in the + + align:start position:0% +I there might be example in the + + + align:start position:0% +I there might be example in the +literature where people were thinking of + + align:start position:0% +literature where people were thinking of + + + align:start position:0% +literature where people were thinking of +other gauge + + align:start position:0% +other gauge + + + align:start position:0% +other gauge +Transformations these are the ones that + + align:start position:0% +Transformations these are the ones that + + + align:start position:0% +Transformations these are the ones that +people talk about now but in the early + + align:start position:0% +people talk about now but in the early + + + align:start position:0% +people talk about now but in the early +days I think there's an example in the + + align:start position:0% +days I think there's an example in the + + + align:start position:0% +days I think there's an example in the +literature where people were thinking of + + align:start position:0% +literature where people were thinking of + + + align:start position:0% +literature where people were thinking of +other Transformations and you could + + align:start position:0% +other Transformations and you could + + + align:start position:0% +other Transformations and you could +prove that they could be connected to + + align:start position:0% +prove that they could be connected to + + + align:start position:0% +prove that they could be connected to +these + + align:start position:0% +these + + + align:start position:0% +these +ones um but we'll just take the the ones + + align:start position:0% +ones um but we'll just take the the ones + + + align:start position:0% +ones um but we'll just take the the ones +that are the most useful from the start + + align:start position:0% +that are the most useful from the start + + + align:start position:0% +that are the most useful from the start +and not worry about too much about what + + align:start position:0% +and not worry about too much about what + + + align:start position:0% +and not worry about too much about what +we could have done + + align:start position:0% + + + + align:start position:0% + +all right so there's no mixing in the + + align:start position:0% +all right so there's no mixing in the + + + align:start position:0% +all right so there's no mixing in the +power counting and that's something that + + align:start position:0% +power counting and that's something that + + + align:start position:0% +power counting and that's something that +we + + align:start position:0% +we + + + align:start position:0% +we +like set up that + + align:start position:0% + + + + align:start position:0% + +way if if there was a mixing if we + + align:start position:0% +way if if there was a mixing if we + + + align:start position:0% +way if if there was a mixing if we +connected things that were different + + align:start position:0% +connected things that were different + + + align:start position:0% +connected things that were different +sizes in Lambda then we would you know + + align:start position:0% +sizes in Lambda then we would you know + + + align:start position:0% +sizes in Lambda then we would you know +you could say well the power counting + + align:start position:0% +you could say well the power counting + + + align:start position:0% +you could say well the power counting +that the the gauge transformation + + align:start position:0% +that the the gauge transformation + + + align:start position:0% +that the the gauge transformation +induces power suppressed terms and you + + align:start position:0% +induces power suppressed terms and you + + + align:start position:0% +induces power suppressed terms and you +could end up with some situation where + + align:start position:0% +could end up with some situation where + + + align:start position:0% +could end up with some situation where +you're trying to connect things at + + align:start position:0% +you're trying to connect things at + + + align:start position:0% +you're trying to connect things at +different orders + + align:start position:0% +different orders + + + align:start position:0% +different orders +and we don't have that + + align:start position:0% + + + + align:start position:0% + +here and that's because if we want to + + align:start position:0% +here and that's because if we want to + + + align:start position:0% +here and that's because if we want to +think about this thing as a as a + + align:start position:0% +think about this thing as a as a + + + align:start position:0% +think about this thing as a as a +symmetry it should really be a symmetry + + align:start position:0% +symmetry it should really be a symmetry + + + align:start position:0% +symmetry it should really be a symmetry +of the leading order action that + + align:start position:0% +of the leading order action that + + + align:start position:0% +of the leading order action that +shouldn't require some other subleading + + align:start position:0% +shouldn't require some other subleading + + + align:start position:0% +shouldn't require some other subleading +terms uh necessarily to to compensate + + align:start position:0% +terms uh necessarily to to compensate + + + align:start position:0% +terms uh necessarily to to compensate +for it at least for a gauge symmetry + + align:start position:0% +for it at least for a gauge symmetry + + + align:start position:0% +for it at least for a gauge symmetry +like this that's we'd like to think that + + align:start position:0% +like this that's we'd like to think that + + + align:start position:0% +like this that's we'd like to think that +what the meaning of gauge symetry is and + + align:start position:0% +what the meaning of gauge symetry is and + + + align:start position:0% +what the meaning of gauge symetry is and +the redundancy encoded engage symmetry + + align:start position:0% +the redundancy encoded engage symmetry + + + align:start position:0% +the redundancy encoded engage symmetry +is all something that you're talking + + align:start position:0% +is all something that you're talking + + + align:start position:0% +is all something that you're talking +about at the order of the leading order + + align:start position:0% +about at the order of the leading order + + + align:start position:0% +about at the order of the leading order +action and you're not talking about + + align:start position:0% +action and you're not talking about + + + align:start position:0% +action and you're not talking about +redundancies and Fields that subleading + + align:start position:0% +redundancies and Fields that subleading + + + align:start position:0% +redundancies and Fields that subleading +order + + align:start position:0% + + + + align:start position:0% + +Etc okay so let's do an example now that + + align:start position:0% +Etc okay so let's do an example now that + + + align:start position:0% +Etc okay so let's do an example now that +we have + + align:start position:0% +we have + + + align:start position:0% +we have +this of sort of how it comes + + align:start position:0% +this of sort of how it comes + + + align:start position:0% +this of sort of how it comes +in and I want to come back to our + + align:start position:0% +in and I want to come back to our + + + align:start position:0% +in and I want to come back to our +example of our heavy Delight + + align:start position:0% + + + + align:start position:0% + +current talk about gauge symmetry there + + align:start position:0% + + + + align:start position:0% + +if you just took the tree level result + + align:start position:0% +if you just took the tree level result + + + align:start position:0% +if you just took the tree level result +that we had in that + + align:start position:0% + + + + align:start position:0% + +case then we had something that just + + align:start position:0% +case then we had something that just + + + align:start position:0% +case then we had something that just +involved these two guys and this HV + + align:start position:0% +involved these two guys and this HV + + + align:start position:0% +involved these two guys and this HV +field was Ultra + + align:start position:0% +field was Ultra + + + align:start position:0% +field was Ultra +Soft this guy's + + align:start position:0% +Soft this guy's + + + align:start position:0% +Soft this guy's +cinear so if you did a UC transformation + + align:start position:0% +cinear so if you did a UC transformation + + + align:start position:0% +cinear so if you did a UC transformation +then under our rules what you'd + + align:start position:0% +then under our rules what you'd + + + align:start position:0% +then under our rules what you'd +find is that the the CN transforms and + + align:start position:0% +find is that the the CN transforms and + + + align:start position:0% +find is that the the CN transforms and +this guy doesn't the H doesn't so that + + align:start position:0% +this guy doesn't the H doesn't so that + + + align:start position:0% +this guy doesn't the H doesn't so that +would not be gaug in + + align:start position:0% + + + + align:start position:0% + +variant but actually we saw that this + + align:start position:0% +variant but actually we saw that this + + + align:start position:0% +variant but actually we saw that this +also wasn't the the the lowest order + + align:start position:0% +also wasn't the the the lowest order + + + align:start position:0% +also wasn't the the the lowest order +current there was this additional thing + + align:start position:0% +current there was this additional thing + + + align:start position:0% +current there was this additional thing +the Wilson line that showed up and that + + align:start position:0% +the Wilson line that showed up and that + + + align:start position:0% +the Wilson line that showed up and that +Wilson line is going to fix this issue + + align:start position:0% +Wilson line is going to fix this issue + + + align:start position:0% +Wilson line is going to fix this issue +it's going to make it gaug + + align:start position:0% + + + + align:start position:0% + +invariant so we have to ask how the + + align:start position:0% +invariant so we have to ask how the + + + align:start position:0% +invariant so we have to ask how the +Wilson lines transform under G + + align:start position:0% + + + + align:start position:0% + +symmetries and that Wilson line in + + align:start position:0% +symmetries and that Wilson line in + + + align:start position:0% +symmetries and that Wilson line in +position + + align:start position:0% + + + + align:start position:0% + +space I called it something like + + align:start position:0% +space I called it something like + + + align:start position:0% +space I called it something like +this can't remember if I used a twiddle + + align:start position:0% +this can't remember if I used a twiddle + + + align:start position:0% +this can't remember if I used a twiddle +or a bar use a bar here for the position + + align:start position:0% +or a bar use a bar here for the position + + + align:start position:0% +or a bar use a bar here for the position +space Wilson + + align:start position:0% +space Wilson + + + align:start position:0% +space Wilson +line so in general in just a regular + + align:start position:0% +line so in general in just a regular + + + align:start position:0% +line so in general in just a regular +gauge Theory the Wilson line between two + + align:start position:0% +gauge Theory the Wilson line between two + + + align:start position:0% +gauge Theory the Wilson line between two +points transforms at the end points so + + align:start position:0% +points transforms at the end points so + + + align:start position:0% +points transforms at the end points so +you get U of + + align:start position:0% + + + + align:start position:0% + +X then you get a UD Dagger of + + align:start position:0% + + + + align:start position:0% + +Y so if you like what we would say for + + align:start position:0% +Y so if you like what we would say for + + + align:start position:0% +Y so if you like what we would say for +this Wilson line is that we have a a u + + align:start position:0% +this Wilson line is that we have a a u + + + align:start position:0% +this Wilson line is that we have a a u +of X on one side and a u Dagger of minus + + align:start position:0% +of X on one side and a u Dagger of minus + + + align:start position:0% +of X on one side and a u Dagger of minus +infinity on the other side + + align:start position:0% + + + + align:start position:0% + +minus infinity is really long wavelength + + align:start position:0% +minus infinity is really long wavelength + + + align:start position:0% +minus infinity is really long wavelength +physics and so we have to worry a little + + align:start position:0% +physics and so we have to worry a little + + + align:start position:0% +physics and so we have to worry a little +bit about the the overlap between our + + align:start position:0% +bit about the the overlap between our + + + align:start position:0% +bit about the the overlap between our +different types of gauge + + align:start position:0% + + + + align:start position:0% + +Transformations I divided them into + + align:start position:0% +Transformations I divided them into + + + align:start position:0% +Transformations I divided them into +three camps colinear ultrasoft and and + + align:start position:0% +three camps colinear ultrasoft and and + + + align:start position:0% +three camps colinear ultrasoft and and +the global so let me do the following + + align:start position:0% + + + + align:start position:0% + +to avoid some double counting with what + + align:start position:0% +to avoid some double counting with what + + + align:start position:0% +to avoid some double counting with what +I called UK Global let's just simply + + align:start position:0% +I called UK Global let's just simply + + + align:start position:0% +I called UK Global let's just simply +take Since U Global acts the same + + align:start position:0% +take Since U Global acts the same + + + align:start position:0% +take Since U Global acts the same +everywhere let's just simply take UC + + align:start position:0% +everywhere let's just simply take UC + + + align:start position:0% +everywhere let's just simply take UC +dagger at minus infinity to be + + align:start position:0% +dagger at minus infinity to be + + + align:start position:0% +dagger at minus infinity to be +one so this is at some particular + + align:start position:0% +one so this is at some particular + + + align:start position:0% +one so this is at some particular +SpaceTime point we take it to be one and + + align:start position:0% +SpaceTime point we take it to be one and + + + align:start position:0% +SpaceTime point we take it to be one and +that Since U Global will transform at + + align:start position:0% +that Since U Global will transform at + + + align:start position:0% +that Since U Global will transform at +that point we then know there's no + + align:start position:0% +that point we then know there's no + + + align:start position:0% +that point we then know there's no +overlap between UC and U global + + align:start position:0% + + + + align:start position:0% + +okay that that's enough to ensure + + align:start position:0% +okay that that's enough to ensure + + + align:start position:0% +okay that that's enough to ensure +that so with + + align:start position:0% +that so with + + + align:start position:0% +that so with +that our guy under a cinear gauge + + align:start position:0% +that our guy under a cinear gauge + + + align:start position:0% +that our guy under a cinear gauge +transformation just transforms on one + + align:start position:0% + + + + align:start position:0% + +side if you like what's happening is + + align:start position:0% +side if you like what's happening is + + + align:start position:0% +side if you like what's happening is +that the coordinate here corresponds to + + align:start position:0% +that the coordinate here corresponds to + + + align:start position:0% +that the coordinate here corresponds to +this very large + + align:start position:0% +this very large + + + align:start position:0% +this very large +momentum and we're stretching ourselves + + align:start position:0% +momentum and we're stretching ourselves + + + align:start position:0% +momentum and we're stretching ourselves +out to small to you know to longdistance + + align:start position:0% +out to small to you know to longdistance + + + align:start position:0% +out to small to you know to longdistance +physics which is corresponding to the + + align:start position:0% +physics which is corresponding to the + + + align:start position:0% +physics which is corresponding to the +smaller + + align:start position:0% +smaller + + + align:start position:0% +smaller +momentum so when I I think about + + align:start position:0% +momentum so when I I think about + + + align:start position:0% +momentum so when I I think about +Transformations that should be cinear I + + align:start position:0% +Transformations that should be cinear I + + + align:start position:0% +Transformations that should be cinear I +want them to be Associated to the X and + + align:start position:0% +want them to be Associated to the X and + + + align:start position:0% +want them to be Associated to the X and +I want to associate other types of + + align:start position:0% +I want to associate other types of + + + align:start position:0% +I want to associate other types of +transformations to what's going on in + + align:start position:0% +transformations to what's going on in + + + align:start position:0% +transformations to what's going on in +Infinity which is really A Spacetime of + + align:start position:0% +Infinity which is really A Spacetime of + + + align:start position:0% +Infinity which is really A Spacetime of +its own which is this ultrasoft space + + align:start position:0% +its own which is this ultrasoft space + + + align:start position:0% +its own which is this ultrasoft space +time that's sitting at sort of the + + align:start position:0% +time that's sitting at sort of the + + + align:start position:0% +time that's sitting at sort of the +cinear + + align:start position:0% +cinear + + + align:start position:0% +cinear +infinity so that's why I want actually + + align:start position:0% +infinity so that's why I want actually + + + align:start position:0% +infinity so that's why I want actually +it to look like + + align:start position:0% +it to look like + + + align:start position:0% +it to look like +this + + align:start position:0% +this + + + align:start position:0% +this +lines just with thear fields or yeah + + align:start position:0% +lines just with thear fields or yeah + + + align:start position:0% +lines just with thear fields or yeah +okay yeah so this guy here was a path + + align:start position:0% +okay yeah so this guy here was a path + + + align:start position:0% +okay yeah so this guy here was a path +exponential and it just invol called the + + align:start position:0% +exponential and it just invol called the + + + align:start position:0% +exponential and it just invol called the +Nar + + align:start position:0% +Nar + + + align:start position:0% +Nar +guy + + align:start position:0% +guy + + + align:start position:0% +guy +yeah so in momentum so that's what it + + align:start position:0% +yeah so in momentum so that's what it + + + align:start position:0% +yeah so in momentum so that's what it +was in position space and in momentum + + align:start position:0% +was in position space and in momentum + + + align:start position:0% +was in position space and in momentum +space we called it + + align:start position:0% +space we called it + + + align:start position:0% +space we called it +w and it you know was a sum over a bunch + + align:start position:0% +w and it you know was a sum over a bunch + + + align:start position:0% +w and it you know was a sum over a bunch +of + + align:start position:0% + + + + align:start position:0% + +things I'm not going + + align:start position:0% + + + + align:start position:0% + +we had this this + + align:start position:0% +we had this this + + + align:start position:0% +we had this this +formula let me not write it all out + + align:start position:0% +formula let me not write it all out + + + align:start position:0% + +[Applause] + + align:start position:0% + + + + align:start position:0% + +again as a kind of short form for that + + align:start position:0% +again as a kind of short form for that + + + align:start position:0% +again as a kind of short form for that +formula we can write the following + + align:start position:0% + + + + align:start position:0% + +formula which is given our notation that + + align:start position:0% +formula which is given our notation that + + + align:start position:0% +formula which is given our notation that +we've developed a useful + + align:start position:0% +we've developed a useful + + + align:start position:0% +we've developed a useful +wave thinking about it so if we formally + + align:start position:0% +wave thinking about it so if we formally + + + align:start position:0% +wave thinking about it so if we formally +expand out this + + align:start position:0% +expand out this + + + align:start position:0% +expand out this +exponential and we just just keep the + + align:start position:0% +exponential and we just just keep the + + + align:start position:0% +exponential and we just just keep the +order of that expansion where the P bar + + align:start position:0% +order of that expansion where the P bar + + + align:start position:0% +order of that expansion where the P bar +acts on all the fields to the right that + + align:start position:0% +acts on all the fields to the right that + + + align:start position:0% +acts on all the fields to the right that +will correctly reproduce this + + align:start position:0% +will correctly reproduce this + + + align:start position:0% +will correctly reproduce this +denominator the sum over perations is + + align:start position:0% +denominator the sum over perations is + + + align:start position:0% +denominator the sum over perations is +something that we still have to do there + + align:start position:0% +something that we still have to do there + + + align:start position:0% +something that we still have to do there +was a 1 over n factorial K factorial in + + align:start position:0% +was a 1 over n factorial K factorial in + + + align:start position:0% +was a 1 over n factorial K factorial in +here M factorial with this + + align:start position:0% +here M factorial with this + + + align:start position:0% +here M factorial with this +notation okay but this is like a little + + align:start position:0% +notation okay but this is like a little + + + align:start position:0% +notation okay but this is like a little +shorthand for that messy + + align:start position:0% + + + + align:start position:0% + +formula + + align:start position:0% +formula + + + align:start position:0% +formula +yeah to + + align:start position:0% +yeah to + + + align:start position:0% +yeah to +yeah how do you get + + align:start position:0% +yeah how do you get + + + align:start position:0% +yeah how do you get +thetion so yeah so that so that actually + + align:start position:0% +thetion so yeah so that so that actually + + + align:start position:0% +thetion so yeah so that so that actually +is related to the fact that when you + + align:start position:0% +is related to the fact that when you + + + align:start position:0% +is related to the fact that when you +look at the for the for this Wilson line + + align:start position:0% +look at the for the for this Wilson line + + + align:start position:0% +look at the for the for this Wilson line +with the iepsilon it's not it's not + + align:start position:0% +with the iepsilon it's not it's not + + + align:start position:0% +with the iepsilon it's not it's not +related to the gauge transformation + + align:start position:0% +related to the gauge transformation + + + align:start position:0% +related to the gauge transformation +Vanishing it want at Infinity but it's + + align:start position:0% +Vanishing it want at Infinity but it's + + + align:start position:0% +Vanishing it want at Infinity but it's +related to the fact that the path goes + + align:start position:0% +related to the fact that the path goes + + + align:start position:0% +related to the fact that the path goes +that way so that the when you do the 4E + + align:start position:0% +that way so that the when you do the 4E + + + align:start position:0% +that way so that the when you do the 4E +integral the fact that it goes from + + align:start position:0% +integral the fact that it goes from + + + align:start position:0% +integral the fact that it goes from +minus in Infinity to X will give the I + + align:start position:0% +minus in Infinity to X will give the I + + + align:start position:0% +minus in Infinity to X will give the I +zero okay but for these Wilson lines + + align:start position:0% +zero okay but for these Wilson lines + + + align:start position:0% +zero okay but for these Wilson lines +here + + align:start position:0% +here + + + align:start position:0% +here +if you think about what's happening at + + align:start position:0% +if you think about what's happening at + + + align:start position:0% +if you think about what's happening at +the place where the i z would actually + + align:start position:0% +the place where the i z would actually + + + align:start position:0% +the place where the i z would actually +matter that's exactly the zero + + align:start position:0% +matter that's exactly the zero + + + align:start position:0% +matter that's exactly the zero +bin so it's going to be a little more + + align:start position:0% +bin so it's going to be a little more + + + align:start position:0% +bin so it's going to be a little more +yeah so you don't really care + + align:start position:0% +yeah so you don't really care + + + align:start position:0% +yeah so you don't really care +but + + align:start position:0% + + + + align:start position:0% + +yeah I can only say that we'll explain + + align:start position:0% +yeah I can only say that we'll explain + + + align:start position:0% +yeah I can only say that we'll explain +what I just said to Il more when we come + + align:start position:0% +what I just said to Il more when we come + + + align:start position:0% +what I just said to Il more when we come +come to it later + + align:start position:0% + + + + align:start position:0% + +on okay so this is this field here has + + align:start position:0% +on okay so this is this field here has + + + align:start position:0% +on okay so this is this field here has +it I I said it's a momentum + + align:start position:0% +it I I said it's a momentum + + + align:start position:0% +it I I said it's a momentum +space but then I wrote X so really what + + align:start position:0% +space but then I wrote X so really what + + + align:start position:0% +space but then I wrote X so really what +I mean by momentum space is momentum is + + align:start position:0% +I mean by momentum space is momentum is + + + align:start position:0% +I mean by momentum space is momentum is +in the label momentum space there's some + + align:start position:0% +in the label momentum space there's some + + + align:start position:0% +in the label momentum space there's some +guy and the labels are these these + + align:start position:0% +guy and the labels are these these + + + align:start position:0% +guy and the labels are these these +labels on the fields here right so + + align:start position:0% +labels on the fields here right so + + + align:start position:0% +labels on the fields here right so +there's still an X and that X + + align:start position:0% +there's still an X and that X + + + align:start position:0% +there's still an X and that X +corresponds to the residual coordinate + + align:start position:0% +corresponds to the residual coordinate + + + align:start position:0% +corresponds to the residual coordinate +that we were using to do the multiple + + align:start position:0% +that we were using to do the multiple + + + align:start position:0% +that we were using to do the multiple +expansion so this is in some sense this + + align:start position:0% +expansion so this is in some sense this + + + align:start position:0% +expansion so this is in some sense this +isn't simply the for transform of that + + align:start position:0% +isn't simply the for transform of that + + + align:start position:0% +isn't simply the for transform of that +because of that it still knows about + + align:start position:0% +because of that it still knows about + + + align:start position:0% +because of that it still knows about +this separation between the large + + align:start position:0% +this separation between the large + + + align:start position:0% +this separation between the large +momentum and the soft momentum + + align:start position:0% +momentum and the soft momentum + + + align:start position:0% +momentum and the soft momentum +from that multipole + + align:start position:0% +from that multipole + + + align:start position:0% +from that multipole +expansion so this dependence on X allows + + align:start position:0% +expansion so this dependence on X allows + + + align:start position:0% +expansion so this dependence on X allows +us to think about the multiple expansion + + align:start position:0% +us to think about the multiple expansion + + + align:start position:0% +us to think about the multiple expansion +on these Wilson + + align:start position:0% +on these Wilson + + + align:start position:0% +on these Wilson +lines encodes all the residual residual + + align:start position:0% +lines encodes all the residual residual + + + align:start position:0% +lines encodes all the residual residual +momenta and the fields in the Wilson + + align:start position:0% +momenta and the fields in the Wilson + + + align:start position:0% +momenta and the fields in the Wilson +line carry residual + + align:start position:0% + + + + align:start position:0% + +momenta so we're just putting our + + align:start position:0% +momenta so we're just putting our + + + align:start position:0% +momenta so we're just putting our +notation to use + + align:start position:0% + + + + align:start position:0% + +here and if you you really strictly want + + align:start position:0% +here and if you you really strictly want + + + align:start position:0% +here and if you you really strictly want +to connect to that formula up there and + + align:start position:0% +to connect to that formula up there and + + + align:start position:0% +to connect to that formula up there and +you would take the residual momentum to + + align:start position:0% +you would take the residual momentum to + + + align:start position:0% +you would take the residual momentum to +be + + align:start position:0% +be + + + align:start position:0% +be +zero and + + align:start position:0% +zero and + + + align:start position:0% +zero and +then the 4 + + align:start position:0% +then the 4 + + + align:start position:0% +then the 4 +transform with respect to just the large + + align:start position:0% +transform with respect to just the large + + + align:start position:0% +transform with respect to just the large +momentum PL + + align:start position:0% + + + + align:start position:0% + +minus gives a + + align:start position:0% +minus gives a + + + align:start position:0% +minus gives a +line which is just depending on that one + + align:start position:0% +line which is just depending on that one + + + align:start position:0% +line which is just depending on that one +single coordinate + + align:start position:0% + + + + align:start position:0% + +so if we just had a coordinate which is + + align:start position:0% +so if we just had a coordinate which is + + + align:start position:0% +so if we just had a coordinate which is +conjugate to the large momenta which is + + align:start position:0% +conjugate to the large momenta which is + + + align:start position:0% +conjugate to the large momenta which is +the thing that's showing up here or the + + align:start position:0% +the thing that's showing up here or the + + + align:start position:0% +the thing that's showing up here or the +large + + align:start position:0% +large + + + align:start position:0% +large +momenta then that you know that would be + + align:start position:0% +momenta then that you know that would be + + + align:start position:0% +momenta then that you know that would be +the analog of what we were talking about + + align:start position:0% +the analog of what we were talking about + + + align:start position:0% +the analog of what we were talking about +up here where in general this thing also + + align:start position:0% +up here where in general this thing also + + + align:start position:0% +up here where in general this thing also +has a dependence on the residual X which + + align:start position:0% +has a dependence on the residual X which + + + align:start position:0% +has a dependence on the residual X which +we'll make use of in a + + align:start position:0% + + + + align:start position:0% + +minute okay so + + align:start position:0% + + + + align:start position:0% + +let's think about so I told you how this + + align:start position:0% +let's think about so I told you how this + + + align:start position:0% +let's think about so I told you how this +Wilson line transforms under UC how does + + align:start position:0% +Wilson line transforms under UC how does + + + align:start position:0% +Wilson line transforms under UC how does +it transform under U + + align:start position:0% +it transform under U + + + align:start position:0% +it transform under U +ultrasoft so under + + align:start position:0% + + + + align:start position:0% + +UC again using this kind of Matrix type + + align:start position:0% +UC again using this kind of Matrix type + + + align:start position:0% +UC again using this kind of Matrix type +notation just UC + + align:start position:0% + + + + align:start position:0% + +so this is a matrix multiplication in + + align:start position:0% +so this is a matrix multiplication in + + + align:start position:0% +so this is a matrix multiplication in +momentum + + align:start position:0% + + + + align:start position:0% + +space what about under a ultrasoft + + align:start position:0% +space what about under a ultrasoft + + + align:start position:0% +space what about under a ultrasoft +transformation well under an ultrasoft + + align:start position:0% +transformation well under an ultrasoft + + + align:start position:0% +transformation well under an ultrasoft +transformation this should be a derived + + align:start position:0% +transformation this should be a derived + + + align:start position:0% +transformation this should be a derived +in some sense under a cinear + + align:start position:0% +in some sense under a cinear + + + align:start position:0% +in some sense under a cinear +transformation it was a derived quantity + + align:start position:0% +transformation it was a derived quantity + + + align:start position:0% +transformation it was a derived quantity +because we knew how the gauge field + + align:start position:0% +because we knew how the gauge field + + + align:start position:0% +because we knew how the gauge field +transform the thing that gave us the + + align:start position:0% +transform the thing that gave us the + + + align:start position:0% +transform the thing that gave us the +transformation of the Wilson line is + + align:start position:0% +transformation of the Wilson line is + + + align:start position:0% +transformation of the Wilson line is +just the transformation of the gauge + + align:start position:0% +just the transformation of the gauge + + + align:start position:0% +just the transformation of the gauge +field okay okay so that's what led to + + align:start position:0% +field okay okay so that's what led to + + + align:start position:0% +field okay okay so that's what led to +that actual this form once we put in + + align:start position:0% +that actual this form once we put in + + + align:start position:0% +that actual this form once we put in +this fact so under the ultrasoft + + align:start position:0% +this fact so under the ultrasoft + + + align:start position:0% +this fact so under the ultrasoft +transformation we just take the + + align:start position:0% +transformation we just take the + + + align:start position:0% +transformation we just take the +transformation that we have for the + + align:start position:0% +transformation that we have for the + + + align:start position:0% +transformation that we have for the +ciner gauge field and then we derive how + + align:start position:0% +ciner gauge field and then we derive how + + + align:start position:0% +ciner gauge field and then we derive how +the ultrasoft GL how the ult how the + + align:start position:0% +the ultrasoft GL how the ult how the + + + align:start position:0% +the ultrasoft GL how the ult how the +Wilson line should transform under the + + align:start position:0% +Wilson line should transform under the + + + align:start position:0% +Wilson line should transform under the +ultrasoft gauge symmetry okay so how + + align:start position:0% +ultrasoft gauge symmetry okay so how + + + align:start position:0% +ultrasoft gauge symmetry okay so how +does this guy + + align:start position:0% +does this guy + + + align:start position:0% +does this guy +transform this guy transforms by putting + + align:start position:0% +transform this guy transforms by putting + + + align:start position:0% +transform this guy transforms by putting +u's on the left and the + + align:start position:0% + + + + align:start position:0% + +right okay that are at X + + align:start position:0% +right okay that are at X + + + align:start position:0% +right okay that are at X +but every field in this exponential has + + align:start position:0% +but every field in this exponential has + + + align:start position:0% +but every field in this exponential has +the same uu dagger multiply think about + + align:start position:0% +the same uu dagger multiply think about + + + align:start position:0% +the same uu dagger multiply think about +expanding that out all the uyu daggers + + align:start position:0% +expanding that out all the uyu daggers + + + align:start position:0% +expanding that out all the uyu daggers +that are next to each other cancel you + + align:start position:0% +that are next to each other cancel you + + + align:start position:0% +that are next to each other cancel you +just get an overall uu dagger that comes + + align:start position:0% +just get an overall uu dagger that comes + + + align:start position:0% +just get an overall uu dagger that comes +right outside the + + align:start position:0% +right outside the + + + align:start position:0% +right outside the +exponential so this + + align:start position:0% +exponential so this + + + align:start position:0% +exponential so this +guy so just transforming with U + + align:start position:0% +guy so just transforming with U + + + align:start position:0% +guy so just transforming with U +ultrasoft of X Wilson line back + + align:start position:0% + + + + align:start position:0% + +again U ultrasoft diag of X and that's + + align:start position:0% +again U ultrasoft diag of X and that's + + + align:start position:0% +again U ultrasoft diag of X and that's +because this Wilson line with our + + align:start position:0% +because this Wilson line with our + + + align:start position:0% +because this Wilson line with our +notation is really a local thing with + + align:start position:0% +notation is really a local thing with + + + align:start position:0% +notation is really a local thing with +respect to the coordinate X all the + + align:start position:0% +respect to the coordinate X all the + + + align:start position:0% +respect to the coordinate X all the +fields sit at + + align:start position:0% +fields sit at + + + align:start position:0% +fields sit at +X okay so it just transforms like that + + align:start position:0% +X okay so it just transforms like that + + + align:start position:0% +X okay so it just transforms like that +because that's how the the gauge field + + align:start position:0% +because that's how the the gauge field + + + align:start position:0% +because that's how the the gauge field +inside it + + align:start position:0% + + + + align:start position:0% + +transforms so in some sense both of + + align:start position:0% +transforms so in some sense both of + + + align:start position:0% +transforms so in some sense both of +these are derived from the + + align:start position:0% +these are derived from the + + + align:start position:0% +these are derived from the +transformation of a + + align:start position:0% +transformation of a + + + align:start position:0% +transformation of a +but it's easier to think about how + + align:start position:0% +but it's easier to think about how + + + align:start position:0% +but it's easier to think about how +Wilson line transforms and then think + + align:start position:0% +Wilson line transforms and then think + + + align:start position:0% +Wilson line transforms and then think +about how it should transform under + + align:start position:0% +about how it should transform under + + + align:start position:0% +about how it should transform under +cinear then just sort of go through the + + align:start position:0% +cinear then just sort of go through the + + + align:start position:0% +cinear then just sort of go through the +route and impose this + + align:start position:0% +route and impose this + + + align:start position:0% +route and impose this +condition okay so let's come back now to + + align:start position:0% +condition okay so let's come back now to + + + align:start position:0% +condition okay so let's come back now to +our our full current which was this that + + align:start position:0% +our our full current which was this that + + + align:start position:0% +our our full current which was this that +had the Wilson line in it and now if you + + align:start position:0% +had the Wilson line in it and now if you + + + align:start position:0% +had the Wilson line in it and now if you +ask how it transforms under UC you see + + align:start position:0% +ask how it transforms under UC you see + + + align:start position:0% +ask how it transforms under UC you see +what's going to + + align:start position:0% +what's going to + + + align:start position:0% +what's going to +happen you get UC + + align:start position:0% +happen you get UC + + + align:start position:0% +happen you get UC +dagger UC and the ultrasoft guy doesn't + + align:start position:0% +dagger UC and the ultrasoft guy doesn't + + + align:start position:0% +dagger UC and the ultrasoft guy doesn't +transform + + align:start position:0% +transform + + + align:start position:0% +transform +and then these cancel so it's invariant + + align:start position:0% +and then these cancel so it's invariant + + + align:start position:0% +and then these cancel so it's invariant +under the Transformations that have + + align:start position:0% +under the Transformations that have + + + align:start position:0% +under the Transformations that have +momenta of order the ultrasoft have + + align:start position:0% +momenta of order the ultrasoft have + + + align:start position:0% +momenta of order the ultrasoft have +momenta of order the cinear scale + + align:start position:0% +momenta of order the cinear scale + + + align:start position:0% +momenta of order the cinear scale +there's two objects in this thing that + + align:start position:0% +there's two objects in this thing that + + + align:start position:0% +there's two objects in this thing that +have momenta that can be of that size + + align:start position:0% +have momenta that can be of that size + + + align:start position:0% +have momenta that can be of that size +the gluons they're in W in this cinear + + align:start position:0% +the gluons they're in W in this cinear + + + align:start position:0% +the gluons they're in W in this cinear +Quark field both of those things + + align:start position:0% +Quark field both of those things + + + align:start position:0% +Quark field both of those things +transform but that transformation + + align:start position:0% +transform but that transformation + + + align:start position:0% +transform but that transformation +cancels between the two + + align:start position:0% + + + + align:start position:0% + +things whoops that's important thank you + + align:start position:0% +things whoops that's important thank you + + + align:start position:0% +things whoops that's important thank you +and then under an ultrasoft + + align:start position:0% +and then under an ultrasoft + + + align:start position:0% +and then under an ultrasoft +transformation we can also transform + + align:start position:0% +transformation we can also transform + + + align:start position:0% +transformation we can also transform +this guy and then everybody's + + align:start position:0% + + + + align:start position:0% + +transforming gamma of course is not got + + align:start position:0% +transforming gamma of course is not got + + + align:start position:0% +transforming gamma of course is not got +color + + align:start position:0% + + + + align:start position:0% + +indices and again it's gaug + + align:start position:0% +indices and again it's gaug + + + align:start position:0% +indices and again it's gaug +invariant okay + + align:start position:0% + + + + align:start position:0% + +missed the + + align:start position:0% + + + + align:start position:0% + +gamma gamma's not so + + align:start position:0% + + + + align:start position:0% + +important all right so this current that + + align:start position:0% +important all right so this current that + + + align:start position:0% +important all right so this current that +we derived earlier is actually in varing + + align:start position:0% +we derived earlier is actually in varing + + + align:start position:0% +we derived earlier is actually in varing +under two different types of symmetries + + align:start position:0% +under two different types of symmetries + + + align:start position:0% +under two different types of symmetries +which are really momentum SP splitting + + align:start position:0% +which are really momentum SP splitting + + + align:start position:0% +which are really momentum SP splitting +of a standard gauge symmetry into pieces + + align:start position:0% +of a standard gauge symmetry into pieces + + + align:start position:0% +of a standard gauge symmetry into pieces +where we have a large momenta and pieces + + align:start position:0% +where we have a large momenta and pieces + + + align:start position:0% +where we have a large momenta and pieces +where we have these Ultra larger momenta + + align:start position:0% +where we have these Ultra larger momenta + + + align:start position:0% +where we have these Ultra larger momenta +cinear momenta and pieces where we have + + align:start position:0% +cinear momenta and pieces where we have + + + align:start position:0% +cinear momenta and pieces where we have +a smaller momenta this ultrasoft momenta + + align:start position:0% +a smaller momenta this ultrasoft momenta + + + align:start position:0% +a smaller momenta this ultrasoft momenta +but both of these types of momenta are + + align:start position:0% +but both of these types of momenta are + + + align:start position:0% +but both of these types of momenta are +momenta that we're allowing inside the + + align:start position:0% +momenta that we're allowing inside the + + + align:start position:0% +momenta that we're allowing inside the +effective the + + align:start position:0% + + + + align:start position:0% + +yeah try to + + align:start position:0% +yeah try to + + + align:start position:0% +yeah try to +remember was + + align:start position:0% +remember was + + + align:start position:0% +remember was +for yeah yeah the the momentum of the + + align:start position:0% +for yeah yeah the the momentum of the + + + align:start position:0% +for yeah yeah the the momentum of the +ultrasoft the the the ultrasoft momentum + + align:start position:0% +ultrasoft the the the ultrasoft momentum + + + align:start position:0% +ultrasoft the the the ultrasoft momentum +of the cinear Quark you pulled out MV + + align:start position:0% +of the cinear Quark you pulled out MV + + + align:start position:0% +of the cinear Quark you pulled out MV +and then the remaining part was + + align:start position:0% +and then the remaining part was + + + align:start position:0% +and then the remaining part was +ultrasoft in the discussion for this + + align:start position:0% +ultrasoft in the discussion for this + + + align:start position:0% +ultrasoft in the discussion for this +particular + + align:start position:0% + + + + align:start position:0% + +thing all + + align:start position:0% + + + + align:start position:0% + +right so it's the Wilson line the moral + + align:start position:0% +right so it's the Wilson line the moral + + + align:start position:0% +right so it's the Wilson line the moral +of this is that what we were doing + + align:start position:0% +of this is that what we were doing + + + align:start position:0% +of this is that what we were doing +before where we're integrating out those + + align:start position:0% +before where we're integrating out those + + + align:start position:0% +before where we're integrating out those +cinear gluons is actually connected to + + align:start position:0% +cinear gluons is actually connected to + + + align:start position:0% +cinear gluons is actually connected to +gauge symmetry because without that + + align:start position:0% +gauge symmetry because without that + + + align:start position:0% +gauge symmetry because without that +Wilson line we wouldn't have a gauge a + + align:start position:0% +Wilson line we wouldn't have a gauge a + + + align:start position:0% +Wilson line we wouldn't have a gauge a +result that's invariant under the type + + align:start position:0% +result that's invariant under the type + + + align:start position:0% +result that's invariant under the type +of gauge simat we've been talking + + align:start position:0% + + + + align:start position:0% + +about so this Wilson line carries these + + align:start position:0% +about so this Wilson line carries these + + + align:start position:0% +about so this Wilson line carries these +n colinear + + align:start position:0% +n colinear + + + align:start position:0% +n colinear +gluons and those gluons would be the + + align:start position:0% +gluons and those gluons would be the + + + align:start position:0% +gluons and those gluons would be the +gluons that in the full Theory would + + align:start position:0% +gluons that in the full Theory would + + + align:start position:0% +gluons that in the full Theory would +give you a gauge symmetric result + + align:start position:0% + + + + align:start position:0% + +they would + + align:start position:0% +they would + + + align:start position:0% +they would +combine they would be the attachments to + + align:start position:0% +combine they would be the attachments to + + + align:start position:0% +combine they would be the attachments to +the heavy quk that attach that combine + + align:start position:0% +the heavy quk that attach that combine + + + align:start position:0% +the heavy quk that attach that combine +with attachments to the light Quark to + + align:start position:0% +with attachments to the light Quark to + + + align:start position:0% +with attachments to the light Quark to +give you sort of a result that's + + align:start position:0% +give you sort of a result that's + + + align:start position:0% +give you sort of a result that's +invariant if you looked at w identities + + align:start position:0% +invariant if you looked at w identities + + + align:start position:0% +invariant if you looked at w identities +for + + align:start position:0% + + + + align:start position:0% + +example but in the effective Theory + + align:start position:0% +example but in the effective Theory + + + align:start position:0% +example but in the effective Theory +these are just put into a Wilson line + + align:start position:0% +these are just put into a Wilson line + + + align:start position:0% +these are just put into a Wilson line +because that's the leading order way + + align:start position:0% +because that's the leading order way + + + align:start position:0% +because that's the leading order way +that they they can show up but still we + + align:start position:0% +that they they can show up but still we + + + align:start position:0% +that they they can show up but still we +have a gauge and variant + + align:start position:0% + + + + align:start position:0% + +answer so the Wilson line is really + + align:start position:0% +answer so the Wilson line is really + + + align:start position:0% +answer so the Wilson line is really +needed for the gauge + + align:start position:0% +needed for the gauge + + + align:start position:0% +needed for the gauge +Symmetry and finally the + + align:start position:0% +Symmetry and finally the + + + align:start position:0% +Symmetry and finally the +ultrasofts as kind of can be clear from + + align:start position:0% +ultrasofts as kind of can be clear from + + + align:start position:0% +ultrasofts as kind of can be clear from +the notation the ultrasofts can just as + + align:start position:0% +the notation the ultrasofts can just as + + + align:start position:0% +the notation the ultrasofts can just as +well include the global + + align:start position:0% +well include the global + + + align:start position:0% +well include the global +transformation if you + + align:start position:0% +transformation if you + + + align:start position:0% +transformation if you +like so we don't really need three we + + align:start position:0% +like so we don't really need three we + + + align:start position:0% +like so we don't really need three we +could put the global back with the + + align:start position:0% +could put the global back with the + + + align:start position:0% +could put the global back with the +ultrasofts + + align:start position:0% + + + + align:start position:0% + +then we just have + + align:start position:0% +then we just have + + + align:start position:0% +then we just have +two all right so that's our symmetry + + align:start position:0% +two all right so that's our symmetry + + + align:start position:0% +two all right so that's our symmetry +that's kind of an example of how it + + align:start position:0% +that's kind of an example of how it + + + align:start position:0% +that's kind of an example of how it +works now let's talk about covariant + + align:start position:0% +works now let's talk about covariant + + + align:start position:0% +works now let's talk about covariant +derivatives + + align:start position:0% + + + + align:start position:0% + +so gauge symmetry ties together regular + + align:start position:0% +so gauge symmetry ties together regular + + + align:start position:0% +so gauge symmetry ties together regular +derivatives with the gauge + + align:start position:0% +derivatives with the gauge + + + align:start position:0% +derivatives with the gauge +field and here what it ties together are + + align:start position:0% +field and here what it ties together are + + + align:start position:0% +field and here what it ties together are +the following + + align:start position:0% + + + + align:start position:0% + +things so because of the treatment of + + align:start position:0% +things so because of the treatment of + + + align:start position:0% +things so because of the treatment of +the a ultrasoft field as a background it + + align:start position:0% +the a ultrasoft field as a background it + + + align:start position:0% +the a ultrasoft field as a background it +actually ties together both of these + + align:start position:0% +actually ties together both of these + + + align:start position:0% +actually ties together both of these +things + + align:start position:0% + + + + align:start position:0% + +and then it kind of does what you expect + + align:start position:0% +and then it kind of does what you expect + + + align:start position:0% +and then it kind of does what you expect +in the cinear sector it ties together + + align:start position:0% +in the cinear sector it ties together + + + align:start position:0% +in the cinear sector it ties together +the derivative with the gauge + + align:start position:0% + + + + align:start position:0% + +field and if you're acting on ultrasoft + + align:start position:0% +field and if you're acting on ultrasoft + + + align:start position:0% +field and if you're acting on ultrasoft +fields then there's an ultrasoft coant + + align:start position:0% +fields then there's an ultrasoft coant + + + align:start position:0% +fields then there's an ultrasoft coant +derivative which is just + + align:start position:0% + + + + align:start position:0% + +like + + align:start position:0% + + + + align:start position:0% + +that so now you can ask the question if + + align:start position:0% +that so now you can ask the question if + + + align:start position:0% +that so now you can ask the question if +I just had this gauge symmetry which is + + align:start position:0% +I just had this gauge symmetry which is + + + align:start position:0% +I just had this gauge symmetry which is +going to force me to use covariant + + align:start position:0% +going to force me to use covariant + + + align:start position:0% +going to force me to use covariant +derivativ which I was already kind of + + align:start position:0% +derivativ which I was already kind of + + + align:start position:0% +derivativ which I was already kind of +thinking ahead to when I wrote down the + + align:start position:0% +thinking ahead to when I wrote down the + + + align:start position:0% +thinking ahead to when I wrote down the +line earlier right we already wrote it + + align:start position:0% +line earlier right we already wrote it + + + align:start position:0% +line earlier right we already wrote it +in terms of these kind of objects so it + + align:start position:0% +in terms of these kind of objects so it + + + align:start position:0% +in terms of these kind of objects so it +seems like we're good to go so you can + + align:start position:0% +seems like we're good to go so you can + + + align:start position:0% +seems like we're good to go so you can +ask the question if I just have power + + align:start position:0% +ask the question if I just have power + + + align:start position:0% +ask the question if I just have power +counting the CN that I we we decided + + align:start position:0% +counting the CN that I we we decided + + + align:start position:0% +counting the CN that I we we decided +work on EOS and and gauge symmetry is + + align:start position:0% +work on EOS and and gauge symmetry is + + + align:start position:0% +work on EOS and and gauge symmetry is +that enough am I done do I have + + align:start position:0% +that enough am I done do I have + + + align:start position:0% +that enough am I done do I have +everything I need for the leading order + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% + + + + align:start position:0% + +lran so power told us that we had this + + align:start position:0% +lran so power told us that we had this + + + align:start position:0% +lran so power told us that we had this +type of derivative and that we could + + align:start position:0% +type of derivative and that we could + + + align:start position:0% +type of derivative and that we could +have two of these per + + align:start position:0% + + + + align:start position:0% + +derivatives okay so those are the two + + align:start position:0% +derivatives okay so those are the two + + + align:start position:0% +derivatives okay so those are the two +type of terms we were getting and + + align:start position:0% +type of terms we were getting and + + + align:start position:0% +type of terms we were getting and +there's no other order Lambda + + align:start position:0% +there's no other order Lambda + + + align:start position:0% +there's no other order Lambda +operators or order Lambda squar other + + align:start position:0% +operators or order Lambda squar other + + + align:start position:0% +operators or order Lambda squar other +sorry there's no other order Lambda + + align:start position:0% +sorry there's no other order Lambda + + + align:start position:0% +sorry there's no other order Lambda +squared field + + align:start position:0% +squared field + + + align:start position:0% +squared field +structures that would be that would have + + align:start position:0% +structures that would be that would have + + + align:start position:0% +structures that would be that would have +the right + + align:start position:0% +the right + + + align:start position:0% +the right +dimensions and + + align:start position:0% +dimensions and + + + align:start position:0% +dimensions and +that could do the job so these are the + + align:start position:0% +that could do the job so these are the + + + align:start position:0% +that could do the job so these are the +really the only two that we have to + + align:start position:0% +really the only two that we have to + + + align:start position:0% +really the only two that we have to +think about so you could try to think + + align:start position:0% +think about so you could try to think + + + align:start position:0% +think about so you could try to think +about you know maybe I can have + + align:start position:0% +about you know maybe I can have + + + align:start position:0% +about you know maybe I can have +something with some additional n bars + + align:start position:0% +something with some additional n bars + + + align:start position:0% +something with some additional n bars +floating + + align:start position:0% +floating + + + align:start position:0% +floating +around but really it boils down since + + align:start position:0% +around but really it boils down since + + + align:start position:0% +around but really it boils down since +you need to get a Lambda squar you need + + align:start position:0% +you need to get a Lambda squar you need + + + align:start position:0% +you need to get a Lambda squar you need +either two per + + align:start position:0% +either two per + + + align:start position:0% +either two per +derivatives the per deriv you need two + + align:start position:0% +derivatives the per deriv you need two + + + align:start position:0% +derivatives the per deriv you need two +of them because of the you still have a + + align:start position:0% +of them because of the you still have a + + + align:start position:0% +of them because of the you still have a +rotation symmetry around the direction + + align:start position:0% +rotation symmetry around the direction + + + align:start position:0% +rotation symmetry around the direction +of motion and you need to or you could + + align:start position:0% +of motion and you need to or you could + + + align:start position:0% +of motion and you need to or you could +have an + + align:start position:0% +have an + + + align:start position:0% +have an +N.D but there is is one operator that is + + align:start position:0% +N.D but there is is one operator that is + + + align:start position:0% +N.D but there is is one operator that is +not rolled + + align:start position:0% + + + + align:start position:0% + +out by gauge symmetry + + align:start position:0% + + + + align:start position:0% + +alone and that isn't this + + align:start position:0% + + + + align:start position:0% + +operator when we wrote the + + align:start position:0% +operator when we wrote the + + + align:start position:0% +operator when we wrote the +operator we had d slash d slash but + + align:start position:0% +operator we had d slash d slash but + + + align:start position:0% +operator we had d slash d slash but +nothing stops me from doing something + + align:start position:0% +nothing stops me from doing something + + + align:start position:0% +nothing stops me from doing something +simpler in some way by just taking the D + + align:start position:0% +simpler in some way by just taking the D + + + align:start position:0% +simpler in some way by just taking the D +perss and Contracting + + align:start position:0% + + + + align:start position:0% + +them like that that's a different + + align:start position:0% +them like that that's a different + + + align:start position:0% +them like that that's a different +operator and the d/d SL operator that we + + align:start position:0% +operator and the d/d SL operator that we + + + align:start position:0% +operator and the d/d SL operator that we +got + + align:start position:0% +got + + + align:start position:0% +got +before whoops only one of + + align:start position:0% +before whoops only one of + + + align:start position:0% +before whoops only one of +those okay so this operator is a + + align:start position:0% +those okay so this operator is a + + + align:start position:0% +those okay so this operator is a +different operator in a priority you + + align:start position:0% +different operator in a priority you + + + align:start position:0% +different operator in a priority you +could say well do Loop Corrections + + align:start position:0% +could say well do Loop Corrections + + + align:start position:0% +could say well do Loop Corrections +generate this operator which is + + align:start position:0% +generate this operator which is + + + align:start position:0% +generate this operator which is +different than the d/d SL + + align:start position:0% +different than the d/d SL + + + align:start position:0% +different than the d/d SL +operator the answer is no + + align:start position:0% +operator the answer is no + + + align:start position:0% +operator the answer is no +actually but so far what we've done it's + + align:start position:0% +actually but so far what we've done it's + + + align:start position:0% +actually but so far what we've done it's +not enough to see + + align:start position:0% + + + + align:start position:0% + +that so we need actually this other + + align:start position:0% +that so we need actually this other + + + align:start position:0% +that so we need actually this other +symmetry that I alluded to the + + align:start position:0% +symmetry that I alluded to the + + + align:start position:0% +symmetry that I alluded to the +reparameterization + + align:start position:0% +reparameterization + + + align:start position:0% +reparameterization +invariance and that will actually rule + + align:start position:0% +invariance and that will actually rule + + + align:start position:0% +invariance and that will actually rule +out this + + align:start position:0% + + + + align:start position:0% + +guy so what's + + align:start position:0% +guy so what's + + + align:start position:0% +guy so what's +RPI well when we formulated this Theory + + align:start position:0% +RPI well when we formulated this Theory + + + align:start position:0% +RPI well when we formulated this Theory +we needed a direction for the cinear + + align:start position:0% +we needed a direction for the cinear + + + align:start position:0% +we needed a direction for the cinear +line for the cinear particles n and then + + align:start position:0% +line for the cinear particles n and then + + + align:start position:0% +line for the cinear particles n and then +we needed an auxiliary Vector n Bar and + + align:start position:0% +we needed an auxiliary Vector n Bar and + + + align:start position:0% +we needed an auxiliary Vector n Bar and +we formulated the whole setup in terms + + align:start position:0% +we formulated the whole setup in terms + + + align:start position:0% +we formulated the whole setup in terms +of this n and n bar but having vectors + + align:start position:0% +of this n and n bar but having vectors + + + align:start position:0% +of this n and n bar but having vectors +like that that we write down that breaks + + align:start position:0% +like that that we write down that breaks + + + align:start position:0% +like that that we write down that breaks +Loren in variance in the same way that + + align:start position:0% +Loren in variance in the same way that + + + align:start position:0% +Loren in variance in the same way that +specifying V mu in + + align:start position:0% +specifying V mu in + + + align:start position:0% +specifying V mu in +h2t breaks Loren inv + + align:start position:0% + + + + align:start position:0% + +variance so if you say that mu mu new is + + align:start position:0% +variance so if you say that mu mu new is + + + align:start position:0% +variance so if you say that mu mu new is +the set of Loren Transformations the + + align:start position:0% +the set of Loren Transformations the + + + align:start position:0% +the set of Loren Transformations the +usual six generators that are anti- + + align:start position:0% +usual six generators that are anti- + + + align:start position:0% +usual six generators that are anti- +symmetric then the ones that are broken + + align:start position:0% +symmetric then the ones that are broken + + + align:start position:0% +symmetric then the ones that are broken +are these + + align:start position:0% + + + + align:start position:0% + +ones and there's five of + + align:start position:0% +ones and there's five of + + + align:start position:0% +ones and there's five of +them and the one that's not + + align:start position:0% + + + + align:start position:0% + +broken is this + + align:start position:0% +broken is this + + + align:start position:0% +broken is this +one which corresponds to rotations about + + align:start position:0% +one which corresponds to rotations about + + + align:start position:0% +one which corresponds to rotations about +the three Axis or the axis specified by + + align:start position:0% +the three Axis or the axis specified by + + + align:start position:0% +the three Axis or the axis specified by +n + + align:start position:0% + + + + align:start position:0% + +okay so those rotations would would act + + align:start position:0% +okay so those rotations would would act + + + align:start position:0% +okay so those rotations would would act +in sort of the components of these guys + + align:start position:0% +in sort of the components of these guys + + + align:start position:0% +in sort of the components of these guys +that are zero if you like so there's no + + align:start position:0% +that are zero if you like so there's no + + + align:start position:0% +that are zero if you like so there's no +issue there and these guys are the guys + + align:start position:0% +issue there and these guys are the guys + + + align:start position:0% +issue there and these guys are the guys +that are are connected to the pieces + + align:start position:0% +that are are connected to the pieces + + + align:start position:0% +that are are connected to the pieces +that were nonzero in + + align:start position:0% +that were nonzero in + + + align:start position:0% +that were nonzero in +general so there's going to be a larger + + align:start position:0% +general so there's going to be a larger + + + align:start position:0% +general so there's going to be a larger +because there's sort of five things here + + align:start position:0% +because there's sort of five things here + + + align:start position:0% +because there's sort of five things here +and because there's there's two vectors + + align:start position:0% +and because there's there's two vectors + + + align:start position:0% +and because there's there's two vectors +it's going to be a larger set of + + align:start position:0% +it's going to be a larger set of + + + align:start position:0% +it's going to be a larger set of +reparameterization symmetries than + + align:start position:0% +reparameterization symmetries than + + + align:start position:0% +reparameterization symmetries than +HQ and there's + + align:start position:0% + + + + align:start position:0% + +actually first talk about just the n and + + align:start position:0% +actually first talk about just the n and + + + align:start position:0% +actually first talk about just the n and +n Bar themselves there's three types of + + align:start position:0% +n Bar themselves there's three types of + + + align:start position:0% +n Bar themselves there's three types of +reparametrization invariance that would + + align:start position:0% + + + + align:start position:0% + +leave n^2 equal 0 and bar^ S equal 0 and + + align:start position:0% +leave n^2 equal 0 and bar^ S equal 0 and + + + align:start position:0% +leave n^2 equal 0 and bar^ S equal 0 and +n. n Bar = 2 and those were the formulas + + align:start position:0% +n. n Bar = 2 and those were the formulas + + + align:start position:0% +n. n Bar = 2 and those were the formulas +that we using over and over again really + + align:start position:0% +that we using over and over again really + + + align:start position:0% +that we using over and over again really +everything else was just + + align:start position:0% +everything else was just + + + align:start position:0% +everything else was just +convention + + align:start position:0% +convention + + + align:start position:0% +convention +okay so what are those three + + align:start position:0% +okay so what are those three + + + align:start position:0% +okay so what are those three +types well we could take n and we could + + align:start position:0% +types well we could take n and we could + + + align:start position:0% +types well we could take n and we could +change it by some amount in the per + + align:start position:0% +change it by some amount in the per + + + align:start position:0% +change it by some amount in the per +Direction and leave n Bar unchanged and + + align:start position:0% +Direction and leave n Bar unchanged and + + + align:start position:0% +Direction and leave n Bar unchanged and +since Nar do something per is zero that + + align:start position:0% +since Nar do something per is zero that + + + align:start position:0% +since Nar do something per is zero that +would be + + align:start position:0% +would be + + + align:start position:0% +would be +a that would satisfy this or we could do + + align:start position:0% +a that would satisfy this or we could do + + + align:start position:0% +a that would satisfy this or we could do +the opposite that would be type + + align:start position:0% +the opposite that would be type + + + align:start position:0% +the opposite that would be type +two so it don't change n + + align:start position:0% +two so it don't change n + + + align:start position:0% +two so it don't change n +and change in + + align:start position:0% + + + + align:start position:0% + +bar and so this is two Transformations + + align:start position:0% +bar and so this is two Transformations + + + align:start position:0% +bar and so this is two Transformations +there's two things specified by this + + align:start position:0% +there's two things specified by this + + + align:start position:0% +there's two things specified by this +this per guy and two here and then + + align:start position:0% +this per guy and two here and then + + + align:start position:0% +this per guy and two here and then +there's one more which is called + + align:start position:0% +there's one more which is called + + + align:start position:0% +there's one more which is called +three and this + + align:start position:0% +three and this + + + align:start position:0% +three and this +one let me write like this it's a + + align:start position:0% +one let me write like this it's a + + + align:start position:0% +one let me write like this it's a +simultaneous transformation of these two + + align:start position:0% + + + + align:start position:0% + +guys where I just do a multip + + align:start position:0% +guys where I just do a multip + + + align:start position:0% +guys where I just do a multip +multiplicative Factor well + + align:start position:0% +multiplicative Factor well + + + align:start position:0% +multiplicative Factor well +multiplicative factor is not going to + + align:start position:0% +multiplicative factor is not going to + + + align:start position:0% +multiplicative factor is not going to +change the fact that's the square of + + align:start position:0% +change the fact that's the square of + + + align:start position:0% +change the fact that's the square of +something zero the place where they + + align:start position:0% +something zero the place where they + + + align:start position:0% +something zero the place where they +where the normalization comes in is this + + align:start position:0% +where the normalization comes in is this + + + align:start position:0% +where the normalization comes in is this +n.n bar and if I just rescale them both + + align:start position:0% +n.n bar and if I just rescale them both + + + align:start position:0% +n.n bar and if I just rescale them both +by an opposite amount then I remain that + + align:start position:0% +by an opposite amount then I remain that + + + align:start position:0% +by an opposite amount then I remain that +remains satisfied as + + align:start position:0% +remains satisfied as + + + align:start position:0% +remains satisfied as +well so I formulated this in terms of an + + align:start position:0% +well so I formulated this in terms of an + + + align:start position:0% +well so I formulated this in terms of an +INF I'm going to think about this as an + + align:start position:0% +INF I'm going to think about this as an + + + align:start position:0% +INF I'm going to think about this as an +infantes transformation for Delta per + + align:start position:0% +infantes transformation for Delta per + + + align:start position:0% +infantes transformation for Delta per +infantes for Epsilon per I could also + + align:start position:0% +infantes for Epsilon per I could also + + + align:start position:0% +infantes for Epsilon per I could also +expand this exponential and think of it + + align:start position:0% +expand this exponential and think of it + + + align:start position:0% +expand this exponential and think of it +as infal but it's even the finite ones + + align:start position:0% +as infal but it's even the finite ones + + + align:start position:0% +as infal but it's even the finite ones +easier so let's just think of the finite + + align:start position:0% +easier so let's just think of the finite + + + align:start position:0% +easier so let's just think of the finite +transformation in the last + + align:start position:0% + + + + align:start position:0% + +one now this is an effective Theory so + + align:start position:0% +one now this is an effective Theory so + + + align:start position:0% +one now this is an effective Theory so +whenever we think about Transformations + + align:start position:0% +whenever we think about Transformations + + + align:start position:0% +whenever we think about Transformations +we should think about power counting we + + align:start position:0% +we should think about power counting we + + + align:start position:0% +we should think about power counting we +just did to spend a lot of time thinking + + align:start position:0% +just did to spend a lot of time thinking + + + align:start position:0% +just did to spend a lot of time thinking +about that for gauge Symmetry and we + + align:start position:0% +about that for gauge Symmetry and we + + + align:start position:0% +about that for gauge Symmetry and we +should think about power counting here + + align:start position:0% +should think about power counting here + + + align:start position:0% +should think about power counting here +too did you have a question + + align:start position:0% + + + + align:start position:0% + +what yeah so well just about to talk + + align:start position:0% +what yeah so well just about to talk + + + align:start position:0% +what yeah so well just about to talk +about how how big the ACT how big things + + align:start position:0% +about how how big the ACT how big things + + + align:start position:0% +about how how big the ACT how big things +can be so + + align:start position:0% +can be so + + + align:start position:0% +can be so +the power counting that's the right + + align:start position:0% +the power counting that's the right + + + align:start position:0% +the power counting that's the right +power counting for these guys so these + + align:start position:0% +power counting for these guys so these + + + align:start position:0% +power counting for these guys so these +things are infal or finite but they also + + align:start position:0% +things are infal or finite but they also + + + align:start position:0% +things are infal or finite but they also +have some counting in a different space + + align:start position:0% +have some counting in a different space + + + align:start position:0% +have some counting in a different space +which is the power counting + + align:start position:0% + + + + align:start position:0% + +space and the right power counting for + + align:start position:0% +space and the right power counting for + + + align:start position:0% +space and the right power counting for +these guys is that is as follows so this + + align:start position:0% +these guys is that is as follows so this + + + align:start position:0% +these guys is that is as follows so this +means I can make arbitrarily large + + align:start position:0% +means I can make arbitrarily large + + + align:start position:0% +means I can make arbitrarily large +transformations in a power counting + + align:start position:0% +transformations in a power counting + + + align:start position:0% +transformations in a power counting +sense of type two and type three there's + + align:start position:0% +sense of type two and type three there's + + + align:start position:0% +sense of type two and type three there's +no constraint that's what this means so + + align:start position:0% +no constraint that's what this means so + + + align:start position:0% +no constraint that's what this means so +maybe that's easier to swallow this one + + align:start position:0% +maybe that's easier to swallow this one + + + align:start position:0% +maybe that's easier to swallow this one +there is a constraint and the reason + + align:start position:0% +there is a constraint and the reason + + + align:start position:0% +there is a constraint and the reason +that you can think of there being a + + align:start position:0% +that you can think of there being a + + + align:start position:0% +that you can think of there being a +constraint we can I can give you a + + align:start position:0% +constraint we can I can give you a + + + align:start position:0% +constraint we can I can give you a +simple + + align:start position:0% +simple + + + align:start position:0% +simple +example and then you'll see how you + + align:start position:0% +example and then you'll see how you + + + align:start position:0% +example and then you'll see how you +would derive the other things as well so + + align:start position:0% +would derive the other things as well so + + + align:start position:0% +would derive the other things as well so +think of n.p if you transform n.p that + + align:start position:0% +think of n.p if you transform n.p that + + + align:start position:0% +think of n.p if you transform n.p that +becomes n do think of this as n mu P + + align:start position:0% +becomes n do think of this as n mu P + + + align:start position:0% +becomes n do think of this as n mu P +mu that becomes n n mu P mu plus Delta + + align:start position:0% + + + + align:start position:0% + +p.p so this is order Lambda squ so this + + align:start position:0% +p.p so this is order Lambda squ so this + + + align:start position:0% +p.p so this is order Lambda squ so this +better be order Lambda squ but this + + align:start position:0% +better be order Lambda squ but this + + + align:start position:0% +better be order Lambda squ but this +momentum here is order Lambda so you + + align:start position:0% +momentum here is order Lambda so you + + + align:start position:0% +momentum here is order Lambda so you +need to have a power counting for the + + align:start position:0% +need to have a power counting for the + + + align:start position:0% +need to have a power counting for the +Delta per that makes it of order + + align:start position:0% +Delta per that makes it of order + + + align:start position:0% +Delta per that makes it of order +Lambda in order to keep the transform + + align:start position:0% +Lambda in order to keep the transform + + + align:start position:0% +Lambda in order to keep the transform +guy the same size as the guy you started + + align:start position:0% +guy the same size as the guy you started + + + align:start position:0% +guy the same size as the guy you started +with because I don't want to consider + + align:start position:0% +with because I don't want to consider + + + align:start position:0% +with because I don't want to consider +Transformations that would take me away + + align:start position:0% +Transformations that would take me away + + + align:start position:0% +Transformations that would take me away +from my power counting that would + + align:start position:0% +from my power counting that would + + + align:start position:0% +from my power counting that would +violate it so the imposing that this + + align:start position:0% +violate it so the imposing that this + + + align:start position:0% +violate it so the imposing that this +thing is a water Lambda + + align:start position:0% +thing is a water Lambda + + + align:start position:0% +thing is a water Lambda +squar says that this is true if you go + + align:start position:0% +squar says that this is true if you go + + + align:start position:0% +squar says that this is true if you go +through the same logic for The Other + + align:start position:0% +through the same logic for The Other + + + align:start position:0% +through the same logic for The Other +Guys well you know the Nar component was + + align:start position:0% +Guys well you know the Nar component was + + + align:start position:0% +Guys well you know the Nar component was +order Lambda 0er so you can make the + + align:start position:0% +order Lambda 0er so you can make the + + + align:start position:0% +order Lambda 0er so you can make the +Epsilon purple order Lambda 0o doesn't + + align:start position:0% +Epsilon purple order Lambda 0o doesn't + + + align:start position:0% +Epsilon purple order Lambda 0o doesn't +cost you anything because there's no + + align:start position:0% + + + + align:start position:0% + +constraint you're not making something + + align:start position:0% +constraint you're not making something + + + align:start position:0% +constraint you're not making something +that would mess up the power + + align:start position:0% + + + + align:start position:0% + +count all + + align:start position:0% +count all + + + align:start position:0% +count all +right so what does this correspond to + + align:start position:0% + + + + align:start position:0% + +physically so type three is actually + + align:start position:0% +physically so type three is actually + + + align:start position:0% +physically so type three is actually +pretty simple simple type three is like + + align:start position:0% +pretty simple simple type three is like + + + align:start position:0% +pretty simple simple type three is like +a boost along if you think about our + + align:start position:0% +a boost along if you think about our + + + align:start position:0% +a boost along if you think about our +backtack vectors type 3 is like the + + align:start position:0% +backtack vectors type 3 is like the + + + align:start position:0% +backtack vectors type 3 is like the +analog of a boost but you're + + align:start position:0% +analog of a boost but you're + + + align:start position:0% +analog of a boost but you're +transforming it in the passive sense of + + align:start position:0% +transforming it in the passive sense of + + + align:start position:0% +transforming it in the passive sense of +transforming the + + align:start position:0% + + + + align:start position:0% + +axis and what the outcome is is very + + align:start position:0% +axis and what the outcome is is very + + + align:start position:0% +axis and what the outcome is is very +simple it just implies that any + + align:start position:0% +simple it just implies that any + + + align:start position:0% +simple it just implies that any +operator that has an + + align:start position:0% + + + + align:start position:0% + +N must have a corresponding n Bar + + align:start position:0% +N must have a corresponding n Bar + + + align:start position:0% +N must have a corresponding n Bar +sitting next to + + align:start position:0% +sitting next to + + + align:start position:0% +sitting next to +it effective + + align:start position:0% + + + + align:start position:0% + +so I'll give you some + + align:start position:0% + + + + align:start position:0% + +examples so really if you have let's + + align:start position:0% +examples so really if you have let's + + + align:start position:0% +examples so really if you have let's +just say it this way if you have an Nar + + align:start position:0% +just say it this way if you have an Nar + + + align:start position:0% +just say it this way if you have an Nar +mu in the + + align:start position:0% + + + + align:start position:0% + +numerator then you either + + align:start position:0% +numerator then you either + + + align:start position:0% +numerator then you either +have a corresponding n in the + + align:start position:0% + + + + align:start position:0% + +numerator or + + align:start position:0% + + + + align:start position:0% + +or you have an Nar in the + + align:start position:0% +or you have an Nar in the + + + align:start position:0% +or you have an Nar in the +denominator since we could have n bars + + align:start position:0% +denominator since we could have n bars + + + align:start position:0% +denominator since we could have n bars +in the + + align:start position:0% +in the + + + align:start position:0% +in the +denominator that was showing up in some + + align:start position:0% +denominator that was showing up in some + + + align:start position:0% +denominator that was showing up in some +places those are the two possible ways + + align:start position:0% +places those are the two possible ways + + + align:start position:0% +places those are the two possible ways +of compensating for the transformation + + align:start position:0% +of compensating for the transformation + + + align:start position:0% +of compensating for the transformation +so it's just like a simple counting that + + align:start position:0% +so it's just like a simple counting that + + + align:start position:0% +so it's just like a simple counting that +you have so if you look at our + + align:start position:0% + + + + align:start position:0% + +lc0 we had various terms one of them was + + align:start position:0% +lc0 we had various terms one of them was + + + align:start position:0% +lc0 we had various terms one of them was +was + + align:start position:0% +was + + + align:start position:0% +was +nar1 over + + align:start position:0% +nar1 over + + + align:start position:0% +nar1 over +I.D so here we have an Nar in both the + + align:start position:0% +I.D so here we have an Nar in both the + + + align:start position:0% +I.D so here we have an Nar in both the +numerator and the denominator and that + + align:start position:0% +numerator and the denominator and that + + + align:start position:0% +numerator and the denominator and that +compensates for the transformation and + + align:start position:0% +compensates for the transformation and + + + align:start position:0% +compensates for the transformation and +then in another term we had an + + align:start position:0% +then in another term we had an + + + align:start position:0% +then in another term we had an +n/ + + align:start position:0% +n/ + + + align:start position:0% +n/ +N.D and then then that again is + + align:start position:0% +N.D and then then that again is + + + align:start position:0% +N.D and then then that again is +invariant to this type of + + align:start position:0% + + + + align:start position:0% + +transformation what about type one and + + align:start position:0% +transformation what about type one and + + + align:start position:0% +transformation what about type one and +two so + + align:start position:0% +two so + + + align:start position:0% +two so +type one is the following so think about + + align:start position:0% +type one is the following so think about + + + align:start position:0% +type one is the following so think about +these guys as in this kind of language + + align:start position:0% +these guys as in this kind of language + + + align:start position:0% +these guys as in this kind of language +they would be back to + + align:start position:0% +they would be back to + + + align:start position:0% +they would be back to +back we're trying to describe the + + align:start position:0% +back we're trying to describe the + + + align:start position:0% +back we're trying to describe the +physics in this cone for the cinear + + align:start position:0% +physics in this cone for the cinear + + + align:start position:0% +physics in this cone for the cinear +particles and N was the vector that was + + align:start position:0% +particles and N was the vector that was + + + align:start position:0% +particles and N was the vector that was +pointing inside that + + align:start position:0% +pointing inside that + + + align:start position:0% +pointing inside that +cone what this is saying type one is + + align:start position:0% +cone what this is saying type one is + + + align:start position:0% +cone what this is saying type one is +that I can rotate that guy and as long + + align:start position:0% +that I can rotate that guy and as long + + + align:start position:0% +that I can rotate that guy and as long +as I'm not rotating it by too much IE + + align:start position:0% +as I'm not rotating it by too much IE + + + align:start position:0% +as I'm not rotating it by too much IE +I'm rotating it by a small amount of + + align:start position:0% +I'm rotating it by a small amount of + + + align:start position:0% +I'm rotating it by a small amount of +order Lambda which you can think of as + + align:start position:0% +order Lambda which you can think of as + + + align:start position:0% +order Lambda which you can think of as +staying inside the + + align:start position:0% +staying inside the + + + align:start position:0% +staying inside the +then I can describe everything equally + + align:start position:0% +then I can describe everything equally + + + align:start position:0% +then I can describe everything equally +well by some other Vector that lives in + + align:start position:0% +well by some other Vector that lives in + + + align:start position:0% +well by some other Vector that lives in +that cone and I can decompose the + + align:start position:0% +that cone and I can decompose the + + + align:start position:0% +that cone and I can decompose the +momento and the modes in terms of that + + align:start position:0% +momento and the modes in terms of that + + + align:start position:0% +momento and the modes in terms of that +Vector it will work equally + + align:start position:0% +Vector it will work equally + + + align:start position:0% +Vector it will work equally +well okay so that's what type + + align:start position:0% +well okay so that's what type + + + align:start position:0% +well okay so that's what type +one is physically doing and so you're + + align:start position:0% +one is physically doing and so you're + + + align:start position:0% +one is physically doing and so you're +not making a large transformation here + + align:start position:0% +not making a large transformation here + + + align:start position:0% +not making a large transformation here +because you want to still be inside the + + align:start position:0% +because you want to still be inside the + + + align:start position:0% +because you want to still be inside the +cone you still want something that's + + align:start position:0% +cone you still want something that's + + + align:start position:0% +cone you still want something that's +pointing in the colinear direction type + + align:start position:0% +pointing in the colinear direction type + + + align:start position:0% +pointing in the colinear direction type +two is related to the fact that this Nar + + align:start position:0% +two is related to the fact that this Nar + + + align:start position:0% +two is related to the fact that this Nar +Vector was just an auxiliary Vector that + + align:start position:0% +Vector was just an auxiliary Vector that + + + align:start position:0% +Vector was just an auxiliary Vector that +we used to decompose things we didn't + + align:start position:0% +we used to decompose things we didn't + + + align:start position:0% +we used to decompose things we didn't +really care about it it didn't have + + align:start position:0% +really care about it it didn't have + + + align:start position:0% +really care about it it didn't have +a a strong + + align:start position:0% +a a strong + + + align:start position:0% +a a strong +physical motivation it was just needed + + align:start position:0% +physical motivation it was just needed + + + align:start position:0% +physical motivation it was just needed +because we're using light cone + + align:start position:0% +because we're using light cone + + + align:start position:0% +because we're using light cone +coordinates so I can make a very large + + align:start position:0% +coordinates so I can make a very large + + + align:start position:0% +coordinates so I can make a very large +transformation of that + + align:start position:0% +transformation of that + + + align:start position:0% +transformation of that +guy so here's a large + + align:start position:0% +guy so here's a large + + + align:start position:0% +guy so here's a large +transformation and I can use some other + + align:start position:0% +transformation and I can use some other + + + align:start position:0% +transformation and I can use some other +guy and we gave you an example earlier + + align:start position:0% +guy and we gave you an example earlier + + + align:start position:0% +guy and we gave you an example earlier +which was 3221 as a possible value for + + align:start position:0% +which was 3221 as a possible value for + + + align:start position:0% +which was 3221 as a possible value for +the Nar and that's you know something + + align:start position:0% +the Nar and that's you know something + + + align:start position:0% +the Nar and that's you know something +that you could think of getting to by a + + align:start position:0% +that you could think of getting to by a + + + align:start position:0% +that you could think of getting to by a +finite type two reparameterization + + align:start position:0% +finite type two reparameterization + + + align:start position:0% +finite type two reparameterization +transformation okay so that's the kind + + align:start position:0% +transformation okay so that's the kind + + + align:start position:0% +transformation okay so that's the kind +of picture for what these + + align:start position:0% +of picture for what these + + + align:start position:0% +of picture for what these +Transformations are and we will finish + + align:start position:0% +Transformations are and we will finish + + + align:start position:0% +Transformations are and we will finish +up talking about them next time and + + align:start position:0% +up talking about them next time and + + + align:start position:0% +up talking about them next time and +we'll show that actually this additional + + align:start position:0% +we'll show that actually this additional + + + align:start position:0% +we'll show that actually this additional +term that we could write down in the + + align:start position:0% +term that we could write down in the + + + align:start position:0% +term that we could write down in the +lran is actually ruled out by + + align:start position:0% +lran is actually ruled out by + + + align:start position:0% +lran is actually ruled out by +reparameterization symmetries \ No newline at end of file diff --git a/X8DlaW83HJc.txt b/X8DlaW83HJc.txt new file mode 100644 index 0000000000000000000000000000000000000000..b47a12afcbdd16898e94291c84887f49e371b0bb --- /dev/null +++ b/X8DlaW83HJc.txt @@ -0,0 +1,2395 @@ +align:start position:0% + +what's the fuel consumption of a car say + + align:start position:0% +what's the fuel consumption of a car say + + + align:start position:0% +what's the fuel consumption of a car say +on the highway moving at highway speeds + + align:start position:0% +on the highway moving at highway speeds + + + align:start position:0% +on the highway moving at highway speeds +we can look it up but can we understand + + align:start position:0% +we can look it up but can we understand + + + align:start position:0% +we can look it up but can we understand +those numbers can we predict them from + + align:start position:0% +those numbers can we predict them from + + + align:start position:0% +those numbers can we predict them from +our knowledge of Science and Engineering + + align:start position:0% +our knowledge of Science and Engineering + + + align:start position:0% +our knowledge of Science and Engineering +that's what we're going to do in this + + align:start position:0% +that's what we're going to do in this + + + align:start position:0% +that's what we're going to do in this +video this video is part of the problem + + align:start position:0% +video this video is part of the problem + + + align:start position:0% +video this video is part of the problem +solving video + + align:start position:0% +solving video + + + align:start position:0% +solving video +series problem solving skills in + + align:start position:0% +series problem solving skills in + + + align:start position:0% +series problem solving skills in +combination with an understanding of the + + align:start position:0% +combination with an understanding of the + + + align:start position:0% +combination with an understanding of the +natural and human-made world are + + align:start position:0% +natural and human-made world are + + + align:start position:0% +natural and human-made world are +critical to the design and optim ization + + align:start position:0% +critical to the design and optim ization + + + align:start position:0% +critical to the design and optim ization +of systems and + + align:start position:0% +of systems and + + + align:start position:0% +of systems and +processes hi my name is sanjoy Mahajan + + align:start position:0% +processes hi my name is sanjoy Mahajan + + + align:start position:0% +processes hi my name is sanjoy Mahajan +and I'm a professor of applied science + + align:start position:0% +and I'm a professor of applied science + + + align:start position:0% +and I'm a professor of applied science +and engineering at Doan college and I + + align:start position:0% +and engineering at Doan college and I + + + align:start position:0% +and engineering at Doan college and I +excel at street fighting mathematics + + align:start position:0% +excel at street fighting mathematics + + + align:start position:0% +excel at street fighting mathematics +before watching this video you should be + + align:start position:0% +before watching this video you should be + + + align:start position:0% +before watching this video you should be +familiar with free body diagrams and + + align:start position:0% +familiar with free body diagrams and + + + align:start position:0% +familiar with free body diagrams and +dimensional + + align:start position:0% +dimensional + + + align:start position:0% +dimensional +analysis after watching this video you + + align:start position:0% +analysis after watching this video you + + + align:start position:0% +analysis after watching this video you +will be able to model drag to predict + + align:start position:0% +will be able to model drag to predict + + + align:start position:0% +will be able to model drag to predict +terminal velocities and determine the + + align:start position:0% +terminal velocities and determine the + + + align:start position:0% +terminal velocities and determine the +fuel efficiency of a car + + align:start position:0% + + + + align:start position:0% + +fuel is consumed in fighting drag on the + + align:start position:0% +fuel is consumed in fighting drag on the + + + align:start position:0% +fuel is consumed in fighting drag on the +highway at least what's the force of + + align:start position:0% +highway at least what's the force of + + + align:start position:0% +highway at least what's the force of +drag on a car that's fluid mechanics we + + align:start position:0% +drag on a car that's fluid mechanics we + + + align:start position:0% +drag on a car that's fluid mechanics we +could try the hard way solving the + + align:start position:0% +could try the hard way solving the + + + align:start position:0% +could try the hard way solving the +navier Stokes equations of fluid + + align:start position:0% +navier Stokes equations of fluid + + + align:start position:0% +navier Stokes equations of fluid +mechanics now after 10 years of learning + + align:start position:0% +mechanics now after 10 years of learning + + + align:start position:0% +mechanics now after 10 years of learning +mathematics you'll discover that this is + + align:start position:0% +mathematics you'll discover that this is + + + align:start position:0% +mathematics you'll discover that this is +a really hard problem you can only Solve + + align:start position:0% +a really hard problem you can only Solve + + + align:start position:0% +a really hard problem you can only Solve +IT analytically in certain special cases + + align:start position:0% +IT analytically in certain special cases + + + align:start position:0% +IT analytically in certain special cases +like a sphere moving at really slow + + align:start position:0% +like a sphere moving at really slow + + + align:start position:0% +like a sphere moving at really slow +speeds and a car is not one of those + + align:start position:0% +speeds and a car is not one of those + + + align:start position:0% +speeds and a car is not one of those +special cases certainly not a car moving + + align:start position:0% +special cases certainly not a car moving + + + align:start position:0% +special cases certainly not a car moving +at any reasonable speed so we need + + align:start position:0% +at any reasonable speed so we need + + + align:start position:0% +at any reasonable speed so we need +another way by applying approximations + + align:start position:0% +another way by applying approximations + + + align:start position:0% +another way by applying approximations +artfully we're going to find the drag + + align:start position:0% +artfully we're going to find the drag + + + align:start position:0% +artfully we're going to find the drag +force and the fuel consumption of a car + + align:start position:0% +force and the fuel consumption of a car + + + align:start position:0% +force and the fuel consumption of a car +with a simple experiment and some + + align:start position:0% +with a simple experiment and some + + + align:start position:0% +with a simple experiment and some +scientific and Engineering + + align:start position:0% + + + + align:start position:0% + +reasoning first we need to model drag to + + align:start position:0% +reasoning first we need to model drag to + + + align:start position:0% +reasoning first we need to model drag to +do this we're going to figure out how + + align:start position:0% +do this we're going to figure out how + + + align:start position:0% +do this we're going to figure out how +the drag Force depends on the quantities + + align:start position:0% +the drag Force depends on the quantities + + + align:start position:0% +the drag Force depends on the quantities +that control it drag Force F depends on + + align:start position:0% +that control it drag Force F depends on + + + align:start position:0% +that control it drag Force F depends on +the density of the air to some power + + align:start position:0% +the density of the air to some power + + + align:start position:0% +the density of the air to some power +which we don't know yet times the speed + + align:start position:0% +which we don't know yet times the speed + + + align:start position:0% +which we don't know yet times the speed +of the car moving through the air to + + align:start position:0% +of the car moving through the air to + + + align:start position:0% +of the car moving through the air to +some power we don't know yet it depends + + align:start position:0% +some power we don't know yet it depends + + + align:start position:0% +some power we don't know yet it depends +on how big the car is which will + + align:start position:0% +on how big the car is which will + + + align:start position:0% +on how big the car is which will +represent by the area traditionally the + + align:start position:0% +represent by the area traditionally the + + + align:start position:0% +represent by the area traditionally the +cross-sectional area to some power and + + align:start position:0% +cross-sectional area to some power and + + + align:start position:0% +cross-sectional area to some power and +it also can depend on the viscosity here + + align:start position:0% +it also can depend on the viscosity here + + + align:start position:0% +it also can depend on the viscosity here +the kinematic viscosity of the air to + + align:start position:0% +the kinematic viscosity of the air to + + + align:start position:0% +the kinematic viscosity of the air to +some power and what those powers are we + + align:start position:0% +some power and what those powers are we + + + align:start position:0% +some power and what those powers are we +don't yet know to figure them out let's + + align:start position:0% +don't yet know to figure them out let's + + + align:start position:0% +don't yet know to figure them out let's +do an experiment for the experiment we + + align:start position:0% +do an experiment for the experiment we + + + align:start position:0% +do an experiment for the experiment we +make two cones first by making a large + + align:start position:0% +make two cones first by making a large + + + align:start position:0% +make two cones first by making a large +Circle and cutting out a quarter of it + + align:start position:0% +Circle and cutting out a quarter of it + + + align:start position:0% +Circle and cutting out a quarter of it +the large Circle has a radius of 7 cm + + align:start position:0% +the large Circle has a radius of 7 cm + + + align:start position:0% +the large Circle has a radius of 7 cm +and the small 3/4 Circle has half the + + align:start position:0% +and the small 3/4 Circle has half the + + + align:start position:0% +and the small 3/4 Circle has half the +radius cut them out and then tape this + + align:start position:0% +radius cut them out and then tape this + + + align:start position:0% +radius cut them out and then tape this +Edge to that edge and this Edge to that + + align:start position:0% +Edge to that edge and this Edge to that + + + align:start position:0% +Edge to that edge and this Edge to that +edge in order to make the two + + align:start position:0% +edge in order to make the two + + + align:start position:0% +edge in order to make the two +cones next we're going to rase them the + + align:start position:0% +cones next we're going to rase them the + + + align:start position:0% +cones next we're going to rase them the +big cone versus the small cone but first + + align:start position:0% +big cone versus the small cone but first + + + align:start position:0% +big cone versus the small cone but first +make a prediction the question is what + + align:start position:0% +make a prediction the question is what + + + align:start position:0% +make a prediction the question is what +is the ratio of fall speeds of the big + + align:start position:0% +is the ratio of fall speeds of the big + + + align:start position:0% +is the ratio of fall speeds of the big +cone and the small cone approximately is + + align:start position:0% +cone and the small cone approximately is + + + align:start position:0% +cone and the small cone approximately is +the big big cone roughly twice as fast + + align:start position:0% +the big big cone roughly twice as fast + + + align:start position:0% +the big big cone roughly twice as fast +is the small cone twice as fast or do + + align:start position:0% +is the small cone twice as fast or do + + + align:start position:0% +is the small cone twice as fast or do +they fall at roughly the same + + align:start position:0% +they fall at roughly the same + + + align:start position:0% +they fall at roughly the same +speed pause the video and make your best + + align:start position:0% +speed pause the video and make your best + + + align:start position:0% +speed pause the video and make your best +guess you may want to try the experiment + + align:start position:0% + + + + align:start position:0% + +yourself the experimental result is that + + align:start position:0% +yourself the experimental result is that + + + align:start position:0% +yourself the experimental result is that +they both fall at roughly the same speed + + align:start position:0% +they both fall at roughly the same speed + + + align:start position:0% +they both fall at roughly the same speed +now what does that mean for the + + align:start position:0% +now what does that mean for the + + + align:start position:0% +now what does that mean for the +exponents in the drag Force to decide + + align:start position:0% +exponents in the drag Force to decide + + + align:start position:0% +exponents in the drag Force to decide +use a free body diagram here is a free + + align:start position:0% +use a free body diagram here is a free + + + align:start position:0% +use a free body diagram here is a free +body diagram of a cone as it falls what + + align:start position:0% +body diagram of a cone as it falls what + + + align:start position:0% +body diagram of a cone as it falls what +are the forces on the cone pause and + + align:start position:0% +are the forces on the cone pause and + + + align:start position:0% +are the forces on the cone pause and +fill in the + + align:start position:0% + + + + align:start position:0% + +diagram there is drag and gravity + + align:start position:0% +diagram there is drag and gravity + + + align:start position:0% +diagram there is drag and gravity +because the cones are falling at their + + align:start position:0% +because the cones are falling at their + + + align:start position:0% +because the cones are falling at their +terminal speed in other words at the + + align:start position:0% +terminal speed in other words at the + + + align:start position:0% +terminal speed in other words at the +constant velocity that they reach pretty + + align:start position:0% +constant velocity that they reach pretty + + + align:start position:0% +constant velocity that they reach pretty +quickly the drag must equal the force + + align:start position:0% +quickly the drag must equal the force + + + align:start position:0% +quickly the drag must equal the force +due to + + align:start position:0% +due to + + + align:start position:0% +due to +gravity so the drag force can easily be + + align:start position:0% +gravity so the drag force can easily be + + + align:start position:0% +gravity so the drag force can easily be +measured just by sticking the cones on a + + align:start position:0% +measured just by sticking the cones on a + + + align:start position:0% +measured just by sticking the cones on a +scale we don't actually have to stick + + align:start position:0% +scale we don't actually have to stick + + + align:start position:0% +scale we don't actually have to stick +the cones on a scale because we know + + align:start position:0% +the cones on a scale because we know + + + align:start position:0% +the cones on a scale because we know +what their relative weights are and + + align:start position:0% +what their relative weights are and + + + align:start position:0% +what their relative weights are and +that's what we're going to use to figure + + align:start position:0% +that's what we're going to use to figure + + + align:start position:0% +that's what we're going to use to figure +out one of the exponents knowing that + + align:start position:0% +out one of the exponents knowing that + + + align:start position:0% +out one of the exponents knowing that +the drag Force equals the force due to + + align:start position:0% +the drag Force equals the force due to + + + align:start position:0% +the drag Force equals the force due to +gravity let's compare the drag forces + + align:start position:0% +gravity let's compare the drag forces + + + align:start position:0% +gravity let's compare the drag forces +which are the factors on the right side + + align:start position:0% +which are the factors on the right side + + + align:start position:0% +which are the factors on the right side +of the small and large + + align:start position:0% +of the small and large + + + align:start position:0% +of the small and large +cones the large cone was made out of a + + align:start position:0% +cones the large cone was made out of a + + + align:start position:0% +cones the large cone was made out of a +paper circle with twice the radius so it + + align:start position:0% +paper circle with twice the radius so it + + + align:start position:0% +paper circle with twice the radius so it +has four times the area four time the + + align:start position:0% +has four times the area four time the + + + align:start position:0% +has four times the area four time the +mass and four times the force due to + + align:start position:0% +mass and four times the force due to + + + align:start position:0% +mass and four times the force due to +gravity therefore four times the drag + + align:start position:0% +gravity therefore four times the drag + + + align:start position:0% +gravity therefore four times the drag +Force now let's look at the causes one + + align:start position:0% +Force now let's look at the causes one + + + align:start position:0% +Force now let's look at the causes one +by one this density here is the density + + align:start position:0% +by one this density here is the density + + + align:start position:0% +by one this density here is the density +of the air and both cones feel the same + + align:start position:0% +of the air and both cones feel the same + + + align:start position:0% +of the air and both cones feel the same +air so there's no difference here so + + align:start position:0% +air so there's no difference here so + + + align:start position:0% +air so there's no difference here so +that's times one no matter the exponent + + align:start position:0% +that's times one no matter the exponent + + + align:start position:0% +that's times one no matter the exponent +now what about the speed the speeds were + + align:start position:0% +now what about the speed the speeds were + + + align:start position:0% +now what about the speed the speeds were +the same that was the result of our + + align:start position:0% +the same that was the result of our + + + align:start position:0% +the same that was the result of our +experiment so no matter what the + + align:start position:0% +experiment so no matter what the + + + align:start position:0% +experiment so no matter what the +exponent here the speed contributes to + + align:start position:0% +exponent here the speed contributes to + + + align:start position:0% +exponent here the speed contributes to +the effect by a factor of one in other + + align:start position:0% +the effect by a factor of one in other + + + align:start position:0% +the effect by a factor of one in other +words + + align:start position:0% +words + + + align:start position:0% +words +nothing now the area this is + + align:start position:0% +nothing now the area this is + + + align:start position:0% +nothing now the area this is +traditionally the cross-sectional area + + align:start position:0% +traditionally the cross-sectional area + + + align:start position:0% +traditionally the cross-sectional area +the big cone has four times the + + align:start position:0% +the big cone has four times the + + + align:start position:0% +the big cone has four times the +cross-sectional area of the small cone + + align:start position:0% +cross-sectional area of the small cone + + + align:start position:0% +cross-sectional area of the small cone +so this area factor is times four and + + align:start position:0% +so this area factor is times four and + + + align:start position:0% +so this area factor is times four and +raised to the unknown + + align:start position:0% +raised to the unknown + + + align:start position:0% +raised to the unknown +exponent and here the kinematic + + align:start position:0% +exponent and here the kinematic + + + align:start position:0% +exponent and here the kinematic +viscosity that's the kinematic viscosity + + align:start position:0% +viscosity that's the kinematic viscosity + + + align:start position:0% +viscosity that's the kinematic viscosity +of air both cones feel the same + + align:start position:0% +of air both cones feel the same + + + align:start position:0% +of air both cones feel the same +kinematic viscosity therefore that + + align:start position:0% +kinematic viscosity therefore that + + + align:start position:0% +kinematic viscosity therefore that +contributes a factor of one just like + + align:start position:0% +contributes a factor of one just like + + + align:start position:0% +contributes a factor of one just like +the density + + align:start position:0% +the density + + + align:start position:0% +the density +does so now we know what the question + + align:start position:0% +does so now we know what the question + + + align:start position:0% +does so now we know what the question +mark here has to be the question mark + + align:start position:0% +mark here has to be the question mark + + + align:start position:0% +mark here has to be the question mark +here must be one so that this four to + + align:start position:0% +here must be one so that this four to + + + align:start position:0% +here must be one so that this four to +the question mark is equal to this + + align:start position:0% +the question mark is equal to this + + + align:start position:0% +the question mark is equal to this +four and so does this + + align:start position:0% + + + + align:start position:0% + +one now that we have found one exponent + + align:start position:0% +one now that we have found one exponent + + + align:start position:0% +one now that we have found one exponent +we can find the remaining three using + + align:start position:0% +we can find the remaining three using + + + align:start position:0% +we can find the remaining three using +dimensional + + align:start position:0% +dimensional + + + align:start position:0% +dimensional +analysis we make sure that the exponents + + align:start position:0% +analysis we make sure that the exponents + + + align:start position:0% +analysis we make sure that the exponents +chosen on the right side produce + + align:start position:0% +chosen on the right side produce + + + align:start position:0% +chosen on the right side produce +dimensions of force which are the + + align:start position:0% +dimensions of force which are the + + + align:start position:0% +dimensions of force which are the +dimensions on the left side a force has + + align:start position:0% +dimensions on the left side a force has + + + align:start position:0% +dimensions on the left side a force has +dimensions of mass length per time + + align:start position:0% +dimensions of mass length per time + + + align:start position:0% +dimensions of mass length per time +squared that's mass times acceleration + + align:start position:0% +squared that's mass times acceleration + + + align:start position:0% +squared that's mass times acceleration +density has dimensions of mass per + + align:start position:0% +density has dimensions of mass per + + + align:start position:0% +density has dimensions of mass per +length cubed raised to this unknown + + align:start position:0% +length cubed raised to this unknown + + + align:start position:0% +length cubed raised to this unknown +exponent velocity has dimensions of + + align:start position:0% +exponent velocity has dimensions of + + + align:start position:0% +exponent velocity has dimensions of +length per time raised to this unknown + + align:start position:0% +length per time raised to this unknown + + + align:start position:0% +length per time raised to this unknown +exponent area has dimensions of length + + align:start position:0% +exponent area has dimensions of length + + + align:start position:0% +exponent area has dimensions of length +squared raised to the power one we've + + align:start position:0% +squared raised to the power one we've + + + align:start position:0% +squared raised to the power one we've +already figured that + + align:start position:0% +already figured that + + + align:start position:0% +already figured that +out and kinematic viscosity now that's + + align:start position:0% +out and kinematic viscosity now that's + + + align:start position:0% +out and kinematic viscosity now that's +the regular viscosity divided by the + + align:start position:0% +the regular viscosity divided by the + + + align:start position:0% +the regular viscosity divided by the +density it has dimensions of length + + align:start position:0% +density it has dimensions of length + + + align:start position:0% +density it has dimensions of length +squared per time raised to this unknown + + align:start position:0% +squared per time raised to this unknown + + + align:start position:0% +squared per time raised to this unknown +exponent + + align:start position:0% + + + + align:start position:0% + +now let's solve for these unknown + + align:start position:0% +now let's solve for these unknown + + + align:start position:0% +now let's solve for these unknown +exponents one at a time looking first at + + align:start position:0% +exponents one at a time looking first at + + + align:start position:0% +exponents one at a time looking first at +the mass there is mass here and mass + + align:start position:0% +the mass there is mass here and mass + + + align:start position:0% +the mass there is mass here and mass +here on the left side but there is no + + align:start position:0% +here on the left side but there is no + + + align:start position:0% +here on the left side but there is no +other Mass so the only way to get the + + align:start position:0% +other Mass so the only way to get the + + + align:start position:0% +other Mass so the only way to get the +mass to work out is to make this + + align:start position:0% +mass to work out is to make this + + + align:start position:0% +mass to work out is to make this +exponent + + align:start position:0% + + + + align:start position:0% + +one now what do we have left we have to + + align:start position:0% +one now what do we have left we have to + + + align:start position:0% +one now what do we have left we have to +make sure the lengths and times work out + + align:start position:0% +make sure the lengths and times work out + + + align:start position:0% +make sure the lengths and times work out +and we have two unknowns this exponent + + align:start position:0% +and we have two unknowns this exponent + + + align:start position:0% +and we have two unknowns this exponent +and this + + align:start position:0% +and this + + + align:start position:0% +and this +exponent let's see how many more lengths + + align:start position:0% +exponent let's see how many more lengths + + + align:start position:0% +exponent let's see how many more lengths +we need given what we already have we + + align:start position:0% +we need given what we already have we + + + align:start position:0% +we need given what we already have we +have mass worked out we have two lengths + + align:start position:0% +have mass worked out we have two lengths + + + align:start position:0% +have mass worked out we have two lengths +here over three lengths so we have mass + + align:start position:0% +here over three lengths so we have mass + + + align:start position:0% +here over three lengths so we have mass +per length so we have length to the + + align:start position:0% +per length so we have length to the + + + align:start position:0% +per length so we have length to the +minus one so + + align:start position:0% +minus one so + + + align:start position:0% +minus one so +far and what about time well we have no + + align:start position:0% +far and what about time well we have no + + + align:start position:0% +far and what about time well we have no +times yet except in these question marks + + align:start position:0% +times yet except in these question marks + + + align:start position:0% +times yet except in these question marks +so we need to get two more times on the + + align:start position:0% +so we need to get two more times on the + + + align:start position:0% +so we need to get two more times on the +bottom two more lengths on the top so we + + align:start position:0% +bottom two more lengths on the top so we + + + align:start position:0% +bottom two more lengths on the top so we +need to multiply by length squar over + + align:start position:0% +need to multiply by length squar over + + + align:start position:0% +need to multiply by length squar over +time squar and the only way to do that + + align:start position:0% +time squar and the only way to do that + + + align:start position:0% +time squar and the only way to do that +is to make this exponent a two and this + + align:start position:0% +is to make this exponent a two and this + + + align:start position:0% +is to make this exponent a two and this +exponent here a + + align:start position:0% +exponent here a + + + align:start position:0% +exponent here a +zero you can pause the video and go + + align:start position:0% +zero you can pause the video and go + + + align:start position:0% +zero you can pause the video and go +ahead and try other combinations of + + align:start position:0% +ahead and try other combinations of + + + align:start position:0% +ahead and try other combinations of +exponents you'll find that none of them + + align:start position:0% +exponents you'll find that none of them + + + align:start position:0% +exponents you'll find that none of them +will get both length and time + + align:start position:0% + + + + align:start position:0% + +correct so now we have all the exponents + + align:start position:0% +correct so now we have all the exponents + + + align:start position:0% +correct so now we have all the exponents +we can actually enter that into our drag + + align:start position:0% +we can actually enter that into our drag + + + align:start position:0% +we can actually enter that into our drag +Force formula drag force is proportional + + align:start position:0% +Force formula drag force is proportional + + + align:start position:0% +Force formula drag force is proportional +to density to the first power to speed + + align:start position:0% +to density to the first power to speed + + + align:start position:0% +to density to the first power to speed +squared to area to the first Power which + + align:start position:0% +squared to area to the first Power which + + + align:start position:0% +squared to area to the first Power which +we got from our home EXP experiment and + + align:start position:0% +we got from our home EXP experiment and + + + align:start position:0% +we got from our home EXP experiment and +to viscosity here to the zeroth + + align:start position:0% +to viscosity here to the zeroth + + + align:start position:0% +to viscosity here to the zeroth +power now let's test our formula with a + + align:start position:0% +power now let's test our formula with a + + + align:start position:0% +power now let's test our formula with a +second demonstration and see if it + + align:start position:0% +second demonstration and see if it + + + align:start position:0% +second demonstration and see if it +predicts this new situation we're going + + align:start position:0% +predicts this new situation we're going + + + align:start position:0% +predicts this new situation we're going +to race four small cones stacked on top + + align:start position:0% +to race four small cones stacked on top + + + align:start position:0% +to race four small cones stacked on top +of each other 1 2 3 4 so we stack them + + align:start position:0% +of each other 1 2 3 4 so we stack them + + + align:start position:0% +of each other 1 2 3 4 so we stack them +to make one small cone that is four time + + align:start position:0% +to make one small cone that is four time + + + align:start position:0% +to make one small cone that is four time +the mass of the other small cone and + + align:start position:0% +the mass of the other small cone and + + + align:start position:0% +the mass of the other small cone and +then we're going to erase them but first + + align:start position:0% +then we're going to erase them but first + + + align:start position:0% +then we're going to erase them but first +what's the drag Force ratio between the + + align:start position:0% +what's the drag Force ratio between the + + + align:start position:0% +what's the drag Force ratio between the +four small cones stacked together and + + align:start position:0% +four small cones stacked together and + + + align:start position:0% +four small cones stacked together and +the single small cone pause the video + + align:start position:0% +the single small cone pause the video + + + align:start position:0% +the single small cone pause the video +and think about + + align:start position:0% + + + + align:start position:0% + +it the four cones weigh four times as + + align:start position:0% +it the four cones weigh four times as + + + align:start position:0% +it the four cones weigh four times as +much as one cone so that's times four on + + align:start position:0% +much as one cone so that's times four on + + + align:start position:0% +much as one cone so that's times four on +the left side what about the right side + + align:start position:0% +the left side what about the right side + + + align:start position:0% +the left side what about the right side +again both contestants feel the same air + + align:start position:0% +again both contestants feel the same air + + + align:start position:0% +again both contestants feel the same air +density the velocity ratio that's what + + align:start position:0% +density the velocity ratio that's what + + + align:start position:0% +density the velocity ratio that's what +we're trying to figure out and let's see + + align:start position:0% +we're trying to figure out and let's see + + + align:start position:0% +we're trying to figure out and let's see +what all the other pieces are the area + + align:start position:0% +what all the other pieces are the area + + + align:start position:0% +what all the other pieces are the area +well here in this case the stack of four + + align:start position:0% +well here in this case the stack of four + + + align:start position:0% +well here in this case the stack of four +has the same cross-sectional area as the + + align:start position:0% +has the same cross-sectional area as the + + + align:start position:0% +has the same cross-sectional area as the +one cone so that's just one and the + + align:start position:0% +one cone so that's just one and the + + + align:start position:0% +one cone so that's just one and the +viscosity doesn't B so this factor of + + align:start position:0% +viscosity doesn't B so this factor of + + + align:start position:0% +viscosity doesn't B so this factor of +four on the left side has to be produced + + align:start position:0% +four on the left side has to be produced + + + align:start position:0% +four on the left side has to be produced +by the v^ s in other words the V goes up + + align:start position:0% +by the v^ s in other words the V goes up + + + align:start position:0% +by the v^ s in other words the V goes up +by factor of two so that when it's + + align:start position:0% +by factor of two so that when it's + + + align:start position:0% +by factor of two so that when it's +squared you get a factor of four that + + align:start position:0% +squared you get a factor of four that + + + align:start position:0% +squared you get a factor of four that +means the correct answer should be 2: + + align:start position:0% +means the correct answer should be 2: + + + align:start position:0% +means the correct answer should be 2: +1 now let's test our prediction with a + + align:start position:0% +1 now let's test our prediction with a + + + align:start position:0% +1 now let's test our prediction with a +demonstration to check whether nature + + align:start position:0% +demonstration to check whether nature + + + align:start position:0% +demonstration to check whether nature +behaves as we + + align:start position:0% + + + + align:start position:0% + +predict it looks like our prediction was + + align:start position:0% +predict it looks like our prediction was + + + align:start position:0% +predict it looks like our prediction was +correct now we feel pretty confident + + align:start position:0% +correct now we feel pretty confident + + + align:start position:0% +correct now we feel pretty confident +that we can use this formula to try and + + align:start position:0% +that we can use this formula to try and + + + align:start position:0% +that we can use this formula to try and +F figure out the fuel consumption of a + + align:start position:0% + + + + align:start position:0% + +car let's clean up our formula here just + + align:start position:0% +car let's clean up our formula here just + + + align:start position:0% +car let's clean up our formula here just +a bit and erase the viscosity since it + + align:start position:0% +a bit and erase the viscosity since it + + + align:start position:0% +a bit and erase the viscosity since it +comes in with a zero exponent so it + + align:start position:0% +comes in with a zero exponent so it + + + align:start position:0% +comes in with a zero exponent so it +doesn't matter and this is our drag + + align:start position:0% +doesn't matter and this is our drag + + + align:start position:0% +doesn't matter and this is our drag +formula which we're going to use to + + align:start position:0% +formula which we're going to use to + + + align:start position:0% +formula which we're going to use to +estimate the fuel consumption of a car + + align:start position:0% +estimate the fuel consumption of a car + + + align:start position:0% +estimate the fuel consumption of a car +on the + + align:start position:0% +on the + + + align:start position:0% +on the +highway fuel efficiency is measured as a + + align:start position:0% +highway fuel efficiency is measured as a + + + align:start position:0% +highway fuel efficiency is measured as a +distance that the car travels on one + + align:start position:0% +distance that the car travels on one + + + align:start position:0% +distance that the car travels on one +gallon or liter of + + align:start position:0% +gallon or liter of + + + align:start position:0% +gallon or liter of +gasoline so it depends on how much + + align:start position:0% +gasoline so it depends on how much + + + align:start position:0% +gasoline so it depends on how much +energy you can get out of a gas G of + + align:start position:0% +energy you can get out of a gas G of + + + align:start position:0% +energy you can get out of a gas G of +gasoline divided by the drag Force which + + align:start position:0% +gasoline divided by the drag Force which + + + align:start position:0% +gasoline divided by the drag Force which +is the formula we've just + + align:start position:0% +is the formula we've just + + + align:start position:0% +is the formula we've just +found so let's put in some numbers + + align:start position:0% +found so let's put in some numbers + + + align:start position:0% +found so let's put in some numbers +what's the energy from a gallon of + + align:start position:0% +what's the energy from a gallon of + + + align:start position:0% +what's the energy from a gallon of +gasoline a gallon is roughly 4 lit and + + align:start position:0% +gasoline a gallon is roughly 4 lit and + + + align:start position:0% +gasoline a gallon is roughly 4 lit and +gasoline is roughly like water so there + + align:start position:0% +gasoline is roughly like water so there + + + align:start position:0% +gasoline is roughly like water so there +are th000 gr per + + align:start position:0% +are th000 gr per + + + align:start position:0% +are th000 gr per +liter how much energy do you get out of + + align:start position:0% +liter how much energy do you get out of + + + align:start position:0% +liter how much energy do you get out of +each gram of gasoline gasoline is like + + align:start position:0% +each gram of gasoline gasoline is like + + + align:start position:0% +each gram of gasoline gasoline is like +fat and from the side of a butter packet + + align:start position:0% +fat and from the side of a butter packet + + + align:start position:0% +fat and from the side of a butter packet +you can read that 100 kilo calories 10 + + align:start position:0% +you can read that 100 kilo calories 10 + + + align:start position:0% +you can read that 100 kilo calories 10 +to the 2 2 kilo calories come from 11 G + + align:start position:0% +to the 2 2 kilo calories come from 11 G + + + align:start position:0% +to the 2 2 kilo calories come from 11 G +of butter but now we want to convert + + align:start position:0% +of butter but now we want to convert + + + align:start position:0% +of butter but now we want to convert +kilo calories to some reasonable metric + + align:start position:0% +kilo calories to some reasonable metric + + + align:start position:0% +kilo calories to some reasonable metric +unit so that's 4 Jew per + + align:start position:0% +unit so that's 4 Jew per + + + align:start position:0% +unit so that's 4 Jew per +calorie or 4 K per kilo + + align:start position:0% +calorie or 4 K per kilo + + + align:start position:0% +calorie or 4 K per kilo +calorie and that is all divided by the + + align:start position:0% +calorie and that is all divided by the + + + align:start position:0% +calorie and that is all divided by the +drag Force so let's put in those terms + + align:start position:0% +drag Force so let's put in those terms + + + align:start position:0% +drag Force so let's put in those terms +one by + + align:start position:0% +one by + + + align:start position:0% +one by +one first the density here 1 kilg per + + align:start position:0% +one first the density here 1 kilg per + + + align:start position:0% +one first the density here 1 kilg per +meter cubed is a density of air roughly + + align:start position:0% +meter cubed is a density of air roughly + + + align:start position:0% +meter cubed is a density of air roughly +now V for highway speeds say 100 km an + + align:start position:0% +now V for highway speeds say 100 km an + + + align:start position:0% +now V for highway speeds say 100 km an +hour 65 M hour that's roughly 30 m/s + + align:start position:0% +hour 65 M hour that's roughly 30 m/s + + + align:start position:0% +hour 65 M hour that's roughly 30 m/s +don't forget to square it and then the + + align:start position:0% +don't forget to square it and then the + + + align:start position:0% +don't forget to square it and then the +area of a car well it's about 2 m wide + + align:start position:0% +area of a car well it's about 2 m wide + + + align:start position:0% +area of a car well it's about 2 m wide +by 1.5 M high now we have to work out + + align:start position:0% +by 1.5 M high now we have to work out + + + align:start position:0% +by 1.5 M high now we have to work out +all the + + align:start position:0% +all the + + + align:start position:0% +all the +numbers before you do that pause the + + align:start position:0% +numbers before you do that pause the + + + align:start position:0% +numbers before you do that pause the +video to check that the dimensions all + + align:start position:0% +video to check that the dimensions all + + + align:start position:0% +video to check that the dimensions all +cancel + + align:start position:0% + + + + align:start position:0% + +appropriately you should have found that + + align:start position:0% +appropriately you should have found that + + + align:start position:0% +appropriately you should have found that +the result has of meters which is good + + align:start position:0% +the result has of meters which is good + + + align:start position:0% +the result has of meters which is good +but how + + align:start position:0% +but how + + + align:start position:0% +but how +many a quick numerical approximation + + align:start position:0% +many a quick numerical approximation + + + align:start position:0% +many a quick numerical approximation +will tell you that you get 50 km which + + align:start position:0% +will tell you that you get 50 km which + + + align:start position:0% +will tell you that you get 50 km which +is 30 m + + align:start position:0% +is 30 m + + + align:start position:0% +is 30 m +roughly the fuel efficiency of a car on + + align:start position:0% +roughly the fuel efficiency of a car on + + + align:start position:0% +roughly the fuel efficiency of a car on +the highway should be about 30 m per + + align:start position:0% +the highway should be about 30 m per + + + align:start position:0% +the highway should be about 30 m per +gallon or 50 km per + + align:start position:0% +gallon or 50 km per + + + align:start position:0% +gallon or 50 km per +gallon in the units used in the European + + align:start position:0% +gallon in the units used in the European + + + align:start position:0% +gallon in the units used in the European +Union that's 8 L per 100 + + align:start position:0% + + + + align:start position:0% + +km with our approximation methods we've + + align:start position:0% +km with our approximation methods we've + + + align:start position:0% +km with our approximation methods we've +come to pretty reasonable numbers for + + align:start position:0% +come to pretty reasonable numbers for + + + align:start position:0% +come to pretty reasonable numbers for +the fuel efficiency of a car without + + align:start position:0% +the fuel efficiency of a car without + + + align:start position:0% +the fuel efficiency of a car without +having to solve any of the complicated + + align:start position:0% +having to solve any of the complicated + + + align:start position:0% +having to solve any of the complicated +equations of fluid mechanics instead we + + align:start position:0% +equations of fluid mechanics instead we + + + align:start position:0% +equations of fluid mechanics instead we +used one simple home experiment dropping + + align:start position:0% +used one simple home experiment dropping + + + align:start position:0% +used one simple home experiment dropping +the cones and the powerful principle of + + align:start position:0% +the cones and the powerful principle of + + + align:start position:0% +the cones and the powerful principle of +dimensional + + align:start position:0% +dimensional + + + align:start position:0% +dimensional +analysis from that we were able to find + + align:start position:0% +analysis from that we were able to find + + + align:start position:0% +analysis from that we were able to find +all the exponents here in the + + align:start position:0% +all the exponents here in the + + + align:start position:0% +all the exponents here in the +relationship between drag and density + + align:start position:0% +relationship between drag and density + + + align:start position:0% +relationship between drag and density +speed and cross-sectional + + align:start position:0% +speed and cross-sectional + + + align:start position:0% +speed and cross-sectional +area so the moral of this is that there + + align:start position:0% +area so the moral of this is that there + + + align:start position:0% +area so the moral of this is that there +is an art to + + align:start position:0% +is an art to + + + align:start position:0% +is an art to +approximations reasoning tools such as + + align:start position:0% +approximations reasoning tools such as + + + align:start position:0% +approximations reasoning tools such as +dimensional analysis give you an + + align:start position:0% +dimensional analysis give you an + + + align:start position:0% +dimensional analysis give you an +understanding of how systems behave + + align:start position:0% +understanding of how systems behave + + + align:start position:0% +understanding of how systems behave +without having to solve every single + + align:start position:0% +without having to solve every single + + + align:start position:0% +without having to solve every single +last bit of the detailed mathematics + + align:start position:0% +last bit of the detailed mathematics + + + align:start position:0% +last bit of the detailed mathematics +this understanding allows us to redesign + + align:start position:0% +this understanding allows us to redesign + + + align:start position:0% +this understanding allows us to redesign +the world + + align:start position:0% + + + + align:start position:0% + +[Music] \ No newline at end of file diff --git a/XKYpKYspe1w.txt b/XKYpKYspe1w.txt new file mode 100644 index 0000000000000000000000000000000000000000..077399b446eb26f3cd04ab88793d2b3d128b20b8 --- /dev/null +++ b/XKYpKYspe1w.txt @@ -0,0 +1,1315 @@ +align:start position:0% + +we are going to spend the rest of this + + align:start position:0% +we are going to spend the rest of this + + + align:start position:0% +we are going to spend the rest of this +lecture by looking into an interesting + + align:start position:0% +lecture by looking into an interesting + + + align:start position:0% +lecture by looking into an interesting +subclass of Markov chains for which + + align:start position:0% +subclass of Markov chains for which + + + align:start position:0% +subclass of Markov chains for which +steady-state convergent exists the class + + align:start position:0% +steady-state convergent exists the class + + + align:start position:0% +steady-state convergent exists the class +of birth and death processes so what is + + align:start position:0% +of birth and death processes so what is + + + align:start position:0% +of birth and death processes so what is +a birth and death process + + align:start position:0% +a birth and death process + + + align:start position:0% +a birth and death process +it's a Markov chain was diagram looks + + align:start position:0% +it's a Markov chain was diagram looks + + + align:start position:0% +it's a Markov chain was diagram looks +like this the states of the Markov chain + + align:start position:0% +like this the states of the Markov chain + + + align:start position:0% +like this the states of the Markov chain +start from zero and go up to some finite + + align:start position:0% +start from zero and go up to some finite + + + align:start position:0% +start from zero and go up to some finite +integer number M and if you are at a + + align:start position:0% +integer number M and if you are at a + + + align:start position:0% +integer number M and if you are at a +typical state in the middle say I then + + align:start position:0% +typical state in the middle say I then + + + align:start position:0% +typical state in the middle say I then +next you will either go to the right or + + align:start position:0% +next you will either go to the right or + + + align:start position:0% +next you will either go to the right or +up by one unit or you will go to the + + align:start position:0% +up by one unit or you will go to the + + + align:start position:0% +up by one unit or you will go to the +left or down by one unit or you will + + align:start position:0% +left or down by one unit or you will + + + align:start position:0% +left or down by one unit or you will +stay where you are + + align:start position:0% +stay where you are + + + align:start position:0% +stay where you are +and this will happen with the following + + align:start position:0% +and this will happen with the following + + + align:start position:0% +and this will happen with the following +transition probabilities here P I I + + align:start position:0% +transition probabilities here P I I + + + align:start position:0% +transition probabilities here P I I +function of the state here Q I and this + + align:start position:0% +function of the state here Q I and this + + + align:start position:0% +function of the state here Q I and this +one the remaining one minus P I minus Q + + align:start position:0% +one the remaining one minus P I minus Q + + + align:start position:0% +one the remaining one minus P I minus Q +I so it's like keeping track of some + + align:start position:0% +I so it's like keeping track of some + + + align:start position:0% +I so it's like keeping track of some +animal population animals get born they + + align:start position:0% +animal population animals get born they + + + align:start position:0% +animal population animals get born they +die the assumption here is that at any + + align:start position:0% +die the assumption here is that at any + + + align:start position:0% +die the assumption here is that at any +point in time either one animal gets + + align:start position:0% +point in time either one animal gets + + + align:start position:0% +point in time either one animal gets +born or one dies or nothing happens + + align:start position:0% +born or one dies or nothing happens + + + align:start position:0% +born or one dies or nothing happens +there are no multiple deaths no births + + align:start position:0% +there are no multiple deaths no births + + + align:start position:0% +there are no multiple deaths no births +happening at the same time there are + + align:start position:0% +happening at the same time there are + + + align:start position:0% +happening at the same time there are +many practical applications where the + + align:start position:0% +many practical applications where the + + + align:start position:0% +many practical applications where the +structure provides a basic first level + + align:start position:0% +structure provides a basic first level + + + align:start position:0% +structure provides a basic first level +Moll an example of a chain of this kind + + align:start position:0% +Moll an example of a chain of this kind + + + align:start position:0% +Moll an example of a chain of this kind +was the supermarket counter example that + + align:start position:0% +was the supermarket counter example that + + + align:start position:0% +was the supermarket counter example that +we discussed before where the states + + align:start position:0% +we discussed before where the states + + + align:start position:0% +we discussed before where the states +represented the number of customers in + + align:start position:0% +represented the number of customers in + + + align:start position:0% +represented the number of customers in +the queue a customer arrives and the + + align:start position:0% +the queue a customer arrives and the + + + align:start position:0% +the queue a customer arrives and the +queue increases by one a customer leaves + + align:start position:0% +queue increases by one a customer leaves + + + align:start position:0% +queue increases by one a customer leaves +and the queue decreases by one or + + align:start position:0% +and the queue decreases by one or + + + align:start position:0% +and the queue decreases by one or +nothing happens and the queue stay as it + + align:start position:0% +nothing happens and the queue stay as it + + + align:start position:0% +nothing happens and the queue stay as it +is now in this supermarket example the + + align:start position:0% +is now in this supermarket example the + + + align:start position:0% +is now in this supermarket example the +peas and the queues were all taken to be + + align:start position:0% +peas and the queues were all taken to be + + + align:start position:0% +peas and the queues were all taken to be +the same across the states but we can + + align:start position:0% +the same across the states but we can + + + align:start position:0% +the same across the states but we can +generalize for example the departure + + align:start position:0% +generalize for example the departure + + + align:start position:0% +generalize for example the departure +rate Q could be different from state to + + align:start position:0% +rate Q could be different from state to + + + align:start position:0% +rate Q could be different from state to +state for example with lots of customers + + align:start position:0% +state for example with lots of customers + + + align:start position:0% +state for example with lots of customers +in the queue perhaps the clerk will work + + align:start position:0% +in the queue perhaps the clerk will work + + + align:start position:0% +in the queue perhaps the clerk will work +faster such a chain can also be used to + + align:start position:0% +faster such a chain can also be used to + + + align:start position:0% +faster such a chain can also be used to +model the spread of disease in + + align:start position:0% +model the spread of disease in + + + align:start position:0% +model the spread of disease in +population for example the states could + + align:start position:0% +population for example the states could + + + align:start position:0% +population for example the states could +represent the number of people in a + + align:start position:0% +represent the number of people in a + + + align:start position:0% +represent the number of people in a +given population that have the flu one + + align:start position:0% +given population that have the flu one + + + align:start position:0% +given population that have the flu one +more person gets the flu the count goes + + align:start position:0% +more person gets the flu the count goes + + + align:start position:0% +more person gets the flu the count goes +up one more person gets healed the count + + align:start position:0% +up one more person gets healed the count + + + align:start position:0% +up one more person gets healed the count +goes down these probabilities in such an + + align:start position:0% +goes down these probabilities in such an + + + align:start position:0% +goes down these probabilities in such an +epidemic Mao would certainly depend on + + align:start position:0% +epidemic Mao would certainly depend on + + + align:start position:0% +epidemic Mao would certainly depend on +the current state if lots of people + + align:start position:0% +the current state if lots of people + + + align:start position:0% +the current state if lots of people +already have the flu the priority that + + align:start position:0% +already have the flu the priority that + + + align:start position:0% +already have the flu the priority that +another person catches it would be + + align:start position:0% +another person catches it would be + + + align:start position:0% +another person catches it would be +pretty high but if no one has the flu + + align:start position:0% +pretty high but if no one has the flu + + + align:start position:0% +pretty high but if no one has the flu +then the priority that one gets a + + align:start position:0% +then the priority that one gets a + + + align:start position:0% +then the priority that one gets a +transition where someone catches the flu + + align:start position:0% +transition where someone catches the flu + + + align:start position:0% +transition where someone catches the flu +would be pretty small the rate at which + + align:start position:0% +would be pretty small the rate at which + + + align:start position:0% +would be pretty small the rate at which +new people get the disease definitely + + align:start position:0% +new people get the disease definitely + + + align:start position:0% +new people get the disease definitely +depends on how many people already have + + align:start position:0% +depends on how many people already have + + + align:start position:0% +depends on how many people already have +it and that motivates cases were those + + align:start position:0% +it and that motivates cases were those + + + align:start position:0% +it and that motivates cases were those +bees here depend on the state of the + + align:start position:0% +bees here depend on the state of the + + + align:start position:0% +bees here depend on the state of the +chain there are lots of other + + align:start position:0% +chain there are lots of other + + + align:start position:0% +chain there are lots of other +applications for which these special + + align:start position:0% +applications for which these special + + + align:start position:0% +applications for which these special +Markov chains are useful so how do we + + align:start position:0% +Markov chains are useful so how do we + + + align:start position:0% +Markov chains are useful so how do we +study them such a chain consists of a + + align:start position:0% +study them such a chain consists of a + + + align:start position:0% +study them such a chain consists of a +single a periodic recurrent class and so + + align:start position:0% +single a periodic recurrent class and so + + + align:start position:0% +single a periodic recurrent class and so +as a well-defined to the state behavior + + align:start position:0% +as a well-defined to the state behavior + + + align:start position:0% +as a well-defined to the state behavior +to calculate the steady-state + + align:start position:0% +to calculate the steady-state + + + align:start position:0% +to calculate the steady-state +probability PI of I of a state I you can + + align:start position:0% +probability PI of I of a state I you can + + + align:start position:0% +probability PI of I of a state I you can +write the system of M linear equations + + align:start position:0% +write the system of M linear equations + + + align:start position:0% +write the system of M linear equations +in the PI's that we had discussed before + + align:start position:0% +in the PI's that we had discussed before + + + align:start position:0% +in the PI's that we had discussed before +but this may be cumbersome and in fact + + align:start position:0% +but this may be cumbersome and in fact + + + align:start position:0% +but this may be cumbersome and in fact +more work than one actually needs to do + + align:start position:0% +more work than one actually needs to do + + + align:start position:0% +more work than one actually needs to do +there is a very clever shortcut that + + align:start position:0% +there is a very clever shortcut that + + + align:start position:0% +there is a very clever shortcut that +applies to birth and death processes and + + align:start position:0% +applies to birth and death processes and + + + align:start position:0% +applies to birth and death processes and +it's based on the frequency + + align:start position:0% +it's based on the frequency + + + align:start position:0% +it's based on the frequency +interpretation that we discussed in the + + align:start position:0% +interpretation that we discussed in the + + + align:start position:0% +interpretation that we discussed in the +recent clip to see this let's draw a + + align:start position:0% +recent clip to see this let's draw a + + + align:start position:0% +recent clip to see this let's draw a +line somewhere in the middle of this + + align:start position:0% +line somewhere in the middle of this + + + align:start position:0% +line somewhere in the middle of this +chain and focus on the transitions + + align:start position:0% +chain and focus on the transitions + + + align:start position:0% +chain and focus on the transitions +between this left part and this right + + align:start position:0% +between this left part and this right + + + align:start position:0% +between this left part and this right +part assume that the line cut through + + align:start position:0% +part assume that the line cut through + + + align:start position:0% +part assume that the line cut through +the middle of two adjacent states I and + + align:start position:0% +the middle of two adjacent states I and + + + align:start position:0% +the middle of two adjacent states I and +I plus one like here and so then you + + align:start position:0% +I plus one like here and so then you + + + align:start position:0% +I plus one like here and so then you +zoom here and this is the picture of + + align:start position:0% +zoom here and this is the picture of + + + align:start position:0% +zoom here and this is the picture of +what you have here so what is the chain + + align:start position:0% +what you have here so what is the chain + + + align:start position:0% +what you have here so what is the chain +going to do let's say it starts on the + + align:start position:0% +going to do let's say it starts on the + + + align:start position:0% +going to do let's say it starts on the +left it's going to move around and at + + align:start position:0% +left it's going to move around and at + + + align:start position:0% +left it's going to move around and at +some point it makes a transition to the + + align:start position:0% +some point it makes a transition to the + + + align:start position:0% +some point it makes a transition to the +other side going here and that is a + + align:start position:0% +other side going here and that is a + + + align:start position:0% +other side going here and that is a +transition + + align:start position:0% +transition + + + align:start position:0% +transition +i to i plus one and now once it's on the + + align:start position:0% +i to i plus one and now once it's on the + + + align:start position:0% +i to i plus one and now once it's on the +right side it's going to move around as + + align:start position:0% +right side it's going to move around as + + + align:start position:0% +right side it's going to move around as +well and then at one point it will come + + align:start position:0% +well and then at one point it will come + + + align:start position:0% +well and then at one point it will come +back to that part again and this is a + + align:start position:0% +back to that part again and this is a + + + align:start position:0% +back to that part again and this is a +transition from i plus 1 to i and so on + + align:start position:0% +transition from i plus 1 to i and so on + + + align:start position:0% +transition from i plus 1 to i and so on +and so forth now there is a certain + + align:start position:0% +and so forth now there is a certain + + + align:start position:0% +and so forth now there is a certain +balance that must be obeyed here the + + align:start position:0% +balance that must be obeyed here the + + + align:start position:0% +balance that must be obeyed here the +number of upward transitions through + + align:start position:0% +number of upward transitions through + + + align:start position:0% +number of upward transitions through +this line cannot be very different from + + align:start position:0% +this line cannot be very different from + + + align:start position:0% +this line cannot be very different from +the number of downward transition from + + align:start position:0% +the number of downward transition from + + + align:start position:0% +the number of downward transition from +this line because if we cross this way + + align:start position:0% +this line because if we cross this way + + + align:start position:0% +this line because if we cross this way +then in order to cross again this way + + align:start position:0% +then in order to cross again this way + + + align:start position:0% +then in order to cross again this way +you will have first to cross down the + + align:start position:0% +you will have first to cross down the + + + align:start position:0% +you will have first to cross down the +other way + + align:start position:0% +other way + + + align:start position:0% +other way +you cannot go up one other times here in + + align:start position:0% +you cannot go up one other times here in + + + align:start position:0% +you cannot go up one other times here in +that direction and go down here 50 times + + align:start position:0% + + + + align:start position:0% + +if you have gone up one other times it + + align:start position:0% +if you have gone up one other times it + + + align:start position:0% +if you have gone up one other times it +means that you have gone down 99 100 or + + align:start position:0% +means that you have gone down 99 100 or + + + align:start position:0% +means that you have gone down 99 100 or +101 but nothing different from that so + + align:start position:0% +101 but nothing different from that so + + + align:start position:0% +101 but nothing different from that so +the long-term frequency with which + + align:start position:0% +the long-term frequency with which + + + align:start position:0% +the long-term frequency with which +transition of this kind occur has to be + + align:start position:0% +transition of this kind occur has to be + + + align:start position:0% +transition of this kind occur has to be +the same as the long-term frequency the + + align:start position:0% +the same as the long-term frequency the + + + align:start position:0% +the same as the long-term frequency the +transition of that kind occur or in this + + align:start position:0% +transition of that kind occur or in this + + + align:start position:0% +transition of that kind occur or in this +diagram the frequency of that kind has + + align:start position:0% +diagram the frequency of that kind has + + + align:start position:0% +diagram the frequency of that kind has +to be the same as the frequency of that + + align:start position:0% +to be the same as the frequency of that + + + align:start position:0% +to be the same as the frequency of that +kind so what are these frequencies we + + align:start position:0% +kind so what are these frequencies we + + + align:start position:0% +kind so what are these frequencies we +discussed that before the fraction of + + align:start position:0% +discussed that before the fraction of + + + align:start position:0% +discussed that before the fraction of +times at which transition of this kind + + align:start position:0% +times at which transition of this kind + + + align:start position:0% +times at which transition of this kind +are observed is the fraction of time + + align:start position:0% +are observed is the fraction of time + + + align:start position:0% +are observed is the fraction of time +that we happen to be at that state which + + align:start position:0% +that we happen to be at that state which + + + align:start position:0% +that we happen to be at that state which +is PI of I and out of the terms that we + + align:start position:0% +is PI of I and out of the terms that we + + + align:start position:0% +is PI of I and out of the terms that we +are in that state the fraction of time + + align:start position:0% +are in that state the fraction of time + + + align:start position:0% +are in that state the fraction of time +that transitions of that time happen is + + align:start position:0% +that transitions of that time happen is + + + align:start position:0% +that transitions of that time happen is +P of I so the overall frequency will be + + align:start position:0% +P of I so the overall frequency will be + + + align:start position:0% +P of I so the overall frequency will be +PI I times P of I and with the same + + align:start position:0% +PI I times P of I and with the same + + + align:start position:0% +PI I times P of I and with the same +argument this is the frequency with + + align:start position:0% +argument this is the frequency with + + + align:start position:0% +argument this is the frequency with +which transition of that kind our + + align:start position:0% +which transition of that kind our + + + align:start position:0% +which transition of that kind our +observed pie I plus 1 times Q I plus 1 + + align:start position:0% +observed pie I plus 1 times Q I plus 1 + + + align:start position:0% +observed pie I plus 1 times Q I plus 1 +since these two frequencies are the same + + align:start position:0% +since these two frequencies are the same + + + align:start position:0% +since these two frequencies are the same +we get an equation that relates PI of I + + align:start position:0% +we get an equation that relates PI of I + + + align:start position:0% +we get an equation that relates PI of I +to PI of I plus one like this so this is + + align:start position:0% +to PI of I plus one like this so this is + + + align:start position:0% +to PI of I plus one like this so this is +the frequency that we observed here of + + align:start position:0% +the frequency that we observed here of + + + align:start position:0% +the frequency that we observed here of +this transition and these are the + + align:start position:0% +this transition and these are the + + + align:start position:0% +this transition and these are the +frequency of these transitions and they + + align:start position:0% +frequency of these transitions and they + + + align:start position:0% +frequency of these transitions and they +had to be equal this has a nice form + + align:start position:0% +had to be equal this has a nice form + + + align:start position:0% +had to be equal this has a nice form +because it gives us a recursion + + align:start position:0% +because it gives us a recursion + + + align:start position:0% +because it gives us a recursion +if we knew PI I you can calculate pi I + + align:start position:0% +if we knew PI I you can calculate pi I + + + align:start position:0% +if we knew PI I you can calculate pi I +plus 1 a search + + align:start position:0% + + + + align:start position:0% + +so it's a system of equations that's + + align:start position:0% +so it's a system of equations that's + + + align:start position:0% +so it's a system of equations that's +easier to solve than the original system + + align:start position:0% +easier to solve than the original system + + + align:start position:0% +easier to solve than the original system +of linear equations which represent it + + align:start position:0% +of linear equations which represent it + + + align:start position:0% +of linear equations which represent it +before for a general Markov chain but + + align:start position:0% +before for a general Markov chain but + + + align:start position:0% +before for a general Markov chain but +how do we get started + + align:start position:0% +how do we get started + + + align:start position:0% +how do we get started +if we knew PI of 0 then we can use it to + + align:start position:0% +if we knew PI of 0 then we can use it to + + + align:start position:0% +if we knew PI of 0 then we can use it to +find PI of 1 then from PI of 1 you can + + align:start position:0% +find PI of 1 then from PI of 1 you can + + + align:start position:0% +find PI of 1 then from PI of 1 you can +get PI of 2 by oh 3 etc but we don't + + align:start position:0% +get PI of 2 by oh 3 etc but we don't + + + align:start position:0% +get PI of 2 by oh 3 etc but we don't +know PI of 0 it's one more unknown it's + + align:start position:0% +know PI of 0 it's one more unknown it's + + + align:start position:0% +know PI of 0 it's one more unknown it's +an unknown and we need to actually use + + align:start position:0% +an unknown and we need to actually use + + + align:start position:0% +an unknown and we need to actually use +the extra normalization conditions that + + align:start position:0% +the extra normalization conditions that + + + align:start position:0% +the extra normalization conditions that +the Sun of all the P I PI J has to be + + align:start position:0% +the Sun of all the P I PI J has to be + + + align:start position:0% +the Sun of all the P I PI J has to be +equal to 1 and after we use that + + align:start position:0% +equal to 1 and after we use that + + + align:start position:0% +equal to 1 and after we use that +normalization condition then we can find + + align:start position:0% +normalization condition then we can find + + + align:start position:0% +normalization condition then we can find +all of the PI by first solving for PI of + + align:start position:0% +all of the PI by first solving for PI of + + + align:start position:0% +all of the PI by first solving for PI of +0 how this can be written PI 0 plus PI 1 + + align:start position:0% +0 how this can be written PI 0 plus PI 1 + + + align:start position:0% +0 how this can be written PI 0 plus PI 1 +which is PI 0 times spiezio over Q 1 + + align:start position:0% +which is PI 0 times spiezio over Q 1 + + + align:start position:0% +which is PI 0 times spiezio over Q 1 +plus PI of 2 which is PI of 1 times P 1 + + align:start position:0% +plus PI of 2 which is PI of 1 times P 1 + + + align:start position:0% +plus PI of 2 which is PI of 1 times P 1 +over Q 2 PI of 0 times P 0 times P 1 + + align:start position:0% +over Q 2 PI of 0 times P 0 times P 1 + + + align:start position:0% +over Q 2 PI of 0 times P 0 times P 1 +over q1 times q2 which is PI 2 plus etc + + align:start position:0% +over q1 times q2 which is PI 2 plus etc + + + align:start position:0% +over q1 times q2 which is PI 2 plus etc +equals 1 so this equation allows us to + + align:start position:0% +equals 1 so this equation allows us to + + + align:start position:0% +equals 1 so this equation allows us to +find PI of 0 and then we use this + + align:start position:0% +find PI of 0 and then we use this + + + align:start position:0% +find PI of 0 and then we use this +recursion to find PI of 1 PI of 2 pi 3 + + align:start position:0% +recursion to find PI of 1 PI of 2 pi 3 + + + align:start position:0% +recursion to find PI of 1 PI of 2 pi 3 +etc \ No newline at end of file diff --git a/XSUjp-cDyeY.txt b/XSUjp-cDyeY.txt new file mode 100644 index 0000000000000000000000000000000000000000..647a60b3799b9b7a56fe66b9c14ca2f939ea07a4 --- /dev/null +++ b/XSUjp-cDyeY.txt @@ -0,0 +1,16347 @@ +align:start position:0% + +let's start with some announcements + + align:start position:0% +let's start with some announcements + + + align:start position:0% +let's start with some announcements +we've had three homework problems and + + align:start position:0% +we've had three homework problems and + + + align:start position:0% +we've had three homework problems and +we're + + align:start position:0% +we're + + + align:start position:0% +we're +ready for the first + + align:start position:0% +ready for the first + + + align:start position:0% +ready for the first +take-home quiz + + align:start position:0% +take-home quiz + + + align:start position:0% +take-home quiz +and the rules again are that it'll count + + align:start position:0% +and the rules again are that it'll count + + + align:start position:0% +and the rules again are that it'll count +twice as much as the homework problem + + align:start position:0% +twice as much as the homework problem + + + align:start position:0% +twice as much as the homework problem +and there's no collaboration unlike + + align:start position:0% +and there's no collaboration unlike + + + align:start position:0% +and there's no collaboration unlike +homework problems + + align:start position:0% +homework problems + + + align:start position:0% +homework problems +so that's uh + + align:start position:0% +so that's uh + + + align:start position:0% +so that's uh +next week + + align:start position:0% +next week + + + align:start position:0% +next week +and then + + align:start position:0% +and then + + + align:start position:0% +and then +those of you in 686 + + align:start position:0% +those of you in 686 + + + align:start position:0% +those of you in 686 +there's a proposal due on the 22nd + + align:start position:0% +there's a proposal due on the 22nd + + + align:start position:0% +there's a proposal due on the 22nd +and that's meant to be + + align:start position:0% + + + + align:start position:0% + +short + + align:start position:0% +short + + + align:start position:0% +short +and that's where you tell me uh what + + align:start position:0% +and that's where you tell me uh what + + + align:start position:0% +and that's where you tell me uh what +you'll be doing for the term project + + align:start position:0% +you'll be doing for the term project + + + align:start position:0% +you'll be doing for the term project +and so + + align:start position:0% +and so + + + align:start position:0% +and so +the idea of the term project is to take + + align:start position:0% +the idea of the term project is to take + + + align:start position:0% +the idea of the term project is to take +some machine vision + + align:start position:0% +some machine vision + + + align:start position:0% +some machine vision +problem uh preferably something we + + align:start position:0% +problem uh preferably something we + + + align:start position:0% +problem uh preferably something we +discussed in class + + align:start position:0% +discussed in class + + + align:start position:0% +discussed in class +and implement it in some way + + align:start position:0% +and implement it in some way + + + align:start position:0% +and implement it in some way +and your choice it could be + + align:start position:0% +and your choice it could be + + + align:start position:0% +and your choice it could be +i don't know windows matlab + + align:start position:0% +i don't know windows matlab + + + align:start position:0% +i don't know windows matlab +android + + align:start position:0% +android + + + align:start position:0% +android +whatever + + align:start position:0% +whatever + + + align:start position:0% +whatever +it could also be something + + align:start position:0% +it could also be something + + + align:start position:0% +it could also be something +more theoretical it could be + + align:start position:0% +more theoretical it could be + + + align:start position:0% +more theoretical it could be +some mathematical solution to some + + align:start position:0% +some mathematical solution to some + + + align:start position:0% +some mathematical solution to some +machine vision problem most people opt + + align:start position:0% +machine vision problem most people opt + + + align:start position:0% +machine vision problem most people opt +to do some kind of implementation + + align:start position:0% +to do some kind of implementation + + + align:start position:0% +to do some kind of implementation +and it's very flexible i mean if you + + align:start position:0% +and it's very flexible i mean if you + + + align:start position:0% +and it's very flexible i mean if you +find that + + align:start position:0% +find that + + + align:start position:0% +find that +you can use opencv + + align:start position:0% +you can use opencv + + + align:start position:0% +you can use opencv +to implement part of what you want to do + + align:start position:0% +to implement part of what you want to do + + + align:start position:0% +to implement part of what you want to do +go ahead and do that but of course then + + align:start position:0% +go ahead and do that but of course then + + + align:start position:0% +go ahead and do that but of course then +your contribution has to be on top of + + align:start position:0% +your contribution has to be on top of + + + align:start position:0% +your contribution has to be on top of +that not just using opencv but + + align:start position:0% +that not just using opencv but + + + align:start position:0% +that not just using opencv but +doing something useful with it + + align:start position:0% +doing something useful with it + + + align:start position:0% +doing something useful with it +and + + align:start position:0% +and + + + align:start position:0% +and +if you have problems coming up with + + align:start position:0% +if you have problems coming up with + + + align:start position:0% +if you have problems coming up with +ideas send me email + + align:start position:0% +ideas send me email + + + align:start position:0% +ideas send me email +what will happen with the proposal is + + align:start position:0% +what will happen with the proposal is + + + align:start position:0% +what will happen with the proposal is +i'll take a look at them and if i can + + align:start position:0% +i'll take a look at them and if i can + + + align:start position:0% +i'll take a look at them and if i can +point you to sources that might be + + align:start position:0% +point you to sources that might be + + + align:start position:0% +point you to sources that might be +helpful in implementing that project + + align:start position:0% +helpful in implementing that project + + + align:start position:0% +helpful in implementing that project +then then i will do so + + align:start position:0% +then then i will do so + + + align:start position:0% +then then i will do so +okay and + + align:start position:0% +okay and + + + align:start position:0% +okay and +we're + + align:start position:0% +we're + + + align:start position:0% +we're +just about to finish our discussion of + + align:start position:0% +just about to finish our discussion of + + + align:start position:0% +just about to finish our discussion of +how to extract stuff from image + + align:start position:0% +how to extract stuff from image + + + align:start position:0% +how to extract stuff from image +brightness + + align:start position:0% +brightness + + + align:start position:0% +brightness +and + + align:start position:0% +and + + + align:start position:0% +and +in particular shape from shading + + align:start position:0% +in particular shape from shading + + + align:start position:0% +in particular shape from shading +and it's a little bit abstract a little + + align:start position:0% +and it's a little bit abstract a little + + + align:start position:0% +and it's a little bit abstract a little +bit mathematical and would soon have a + + align:start position:0% +bit mathematical and would soon have a + + + align:start position:0% +bit mathematical and would soon have a +big change of pace + + align:start position:0% +big change of pace + + + align:start position:0% +big change of pace +when we start talking about industrial + + align:start position:0% +when we start talking about industrial + + + align:start position:0% +when we start talking about industrial +machine vision + + align:start position:0% +machine vision + + + align:start position:0% +machine vision +and of course we can't cover everything + + align:start position:0% +and of course we can't cover everything + + + align:start position:0% +and of course we can't cover everything +and we'll take a different approach to + + align:start position:0% +and we'll take a different approach to + + + align:start position:0% +and we'll take a different approach to +covering it so rather than use published + + align:start position:0% +covering it so rather than use published + + + align:start position:0% +covering it so rather than use published +papers + + align:start position:0% +papers + + + align:start position:0% +papers +or textbooks + + align:start position:0% +or textbooks + + + align:start position:0% +or textbooks +we'll look at patents and part of the + + align:start position:0% +we'll look at patents and part of the + + + align:start position:0% +we'll look at patents and part of the +reason for that is that you know in our + + align:start position:0% +reason for that is that you know in our + + + align:start position:0% +reason for that is that you know in our +world you publish papers that's what you + + align:start position:0% +world you publish papers that's what you + + + align:start position:0% +world you publish papers that's what you +get credit for + + align:start position:0% +get credit for + + + align:start position:0% +get credit for +in their world you don't publish that's + + align:start position:0% +in their world you don't publish that's + + + align:start position:0% +in their world you don't publish that's +what you get credit for so + + align:start position:0% +what you get credit for so + + + align:start position:0% +what you get credit for so +when you do see what they're doing + + align:start position:0% +when you do see what they're doing + + + align:start position:0% +when you do see what they're doing +it's in the patents where they're trying + + align:start position:0% +it's in the patents where they're trying + + + align:start position:0% +it's in the patents where they're trying +to cover themselves + + align:start position:0% +to cover themselves + + + align:start position:0% +to cover themselves +uh + + align:start position:0% +uh + + + align:start position:0% +uh +uh + + align:start position:0% +uh + + + align:start position:0% +uh +protect themselves from somebody else + + align:start position:0% +protect themselves from somebody else + + + align:start position:0% +protect themselves from somebody else +using that same idea so that'll be a big + + align:start position:0% +using that same idea so that'll be a big + + + align:start position:0% +using that same idea so that'll be a big +change of pace and in the process we'll + + align:start position:0% +change of pace and in the process we'll + + + align:start position:0% +change of pace and in the process we'll +learn a little bit about + + align:start position:0% +learn a little bit about + + + align:start position:0% +learn a little bit about +patents and patent language + + align:start position:0% +patents and patent language + + + align:start position:0% +patents and patent language +since you know that's a + + align:start position:0% +since you know that's a + + + align:start position:0% +since you know that's a +important topic if you're + + align:start position:0% +important topic if you're + + + align:start position:0% +important topic if you're +an entrepreneur + + align:start position:0% +an entrepreneur + + + align:start position:0% +an entrepreneur +involved in a startup or something of + + align:start position:0% +involved in a startup or something of + + + align:start position:0% +involved in a startup or something of +that sort so obviously that's going to + + align:start position:0% +that sort so obviously that's going to + + + align:start position:0% +that sort so obviously that's going to +be a little different from partial + + align:start position:0% +be a little different from partial + + + align:start position:0% +be a little different from partial +differential equations + + align:start position:0% +differential equations + + + align:start position:0% +differential equations +and some of you may be looking forward + + align:start position:0% +and some of you may be looking forward + + + align:start position:0% +and some of you may be looking forward +to that but but let's finish with the + + align:start position:0% +to that but but let's finish with the + + + align:start position:0% +to that but but let's finish with the +partial differential equations so where + + align:start position:0% +partial differential equations so where + + + align:start position:0% +partial differential equations so where +are we oh okay + + align:start position:0% +are we oh okay + + + align:start position:0% +are we oh okay +well + + align:start position:0% +well + + + align:start position:0% +well +for example you could implement time to + + align:start position:0% +for example you could implement time to + + + align:start position:0% +for example you could implement time to +contact on your android phone + + align:start position:0% +contact on your android phone + + + align:start position:0% +contact on your android phone +and + + align:start position:0% +and + + + align:start position:0% +and +in that case + + align:start position:0% +in that case + + + align:start position:0% +in that case +you'd use android studio + + align:start position:0% +you'd use android studio + + + align:start position:0% +you'd use android studio +and + + align:start position:0% +and + + + align:start position:0% +and +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +i could supply you with a dummy project + + align:start position:0% +i could supply you with a dummy project + + + align:start position:0% +i could supply you with a dummy project +that's just a shell + + align:start position:0% +that's just a shell + + + align:start position:0% +that's just a shell +so that you don't have to uh write all + + align:start position:0% +so that you don't have to uh write all + + + align:start position:0% +so that you don't have to uh write all +of those files for android studio so + + align:start position:0% +of those files for android studio so + + + align:start position:0% +of those files for android studio so +that's an example um + + align:start position:0% + + + + align:start position:0% + +you could uh implement some of the + + align:start position:0% +you could uh implement some of the + + + align:start position:0% +you could uh implement some of the +subpixel + + align:start position:0% +subpixel + + + align:start position:0% +subpixel +methods that we'll talk about + + align:start position:0% +methods that we'll talk about + + + align:start position:0% +methods that we'll talk about +for + + align:start position:0% +for + + + align:start position:0% +for +edge detection + + align:start position:0% +edge detection + + + align:start position:0% +edge detection +and use + + align:start position:0% +and use + + + align:start position:0% +and use +whatever matlab + + align:start position:0% +whatever matlab + + + align:start position:0% +whatever matlab +whatever is convenient + + align:start position:0% +whatever is convenient + + + align:start position:0% +whatever is convenient +um so + + align:start position:0% +um so + + + align:start position:0% +um so +that's an example project + + align:start position:0% +that's an example project + + + align:start position:0% +that's an example project +another example more theoretical would + + align:start position:0% +another example more theoretical would + + + align:start position:0% +another example more theoretical would +be + + align:start position:0% +be + + + align:start position:0% +be +you know we've talked about + + align:start position:0% +you know we've talked about + + + align:start position:0% +you know we've talked about +shape from shading in the context of + + align:start position:0% +shape from shading in the context of + + + align:start position:0% +shape from shading in the context of +particular types of reflectance maps + + align:start position:0% +particular types of reflectance maps + + + align:start position:0% +particular types of reflectance maps +like hapki + + align:start position:0% +like hapki + + + align:start position:0% +like hapki +and you could implement you could work + + align:start position:0% +and you could implement you could work + + + align:start position:0% +and you could implement you could work +out the details for a different type of + + align:start position:0% +out the details for a different type of + + + align:start position:0% +out the details for a different type of +reflectance map there would be a more + + align:start position:0% +reflectance map there would be a more + + + align:start position:0% +reflectance map there would be a more +abstract mathematical project + + align:start position:0% +abstract mathematical project + + + align:start position:0% +abstract mathematical project +and + + align:start position:0% +and + + + align:start position:0% +and +i think what i'll do is i'll pull + + align:start position:0% +i think what i'll do is i'll pull + + + align:start position:0% +i think what i'll do is i'll pull +together some of those and + + align:start position:0% +together some of those and + + + align:start position:0% +together some of those and +maybe say something about them on on the + + align:start position:0% +maybe say something about them on on the + + + align:start position:0% +maybe say something about them on on the +stella website + + align:start position:0% +stella website + + + align:start position:0% +stella website +so + + align:start position:0% + + + + align:start position:0% + +okay so uh + + align:start position:0% +okay so uh + + + align:start position:0% +okay so uh +the first part of the term we were + + align:start position:0% +the first part of the term we were + + + align:start position:0% +the first part of the term we were +focusing mostly on + + align:start position:0% +focusing mostly on + + + align:start position:0% +focusing mostly on +image projection perspective projection + + align:start position:0% +image projection perspective projection + + + align:start position:0% +image projection perspective projection +equation and derivatives motion + + align:start position:0% +equation and derivatives motion + + + align:start position:0% +equation and derivatives motion +motion in the world motion in the image + + align:start position:0% +motion in the world motion in the image + + + align:start position:0% +motion in the world motion in the image +and then we switch to + + align:start position:0% +and then we switch to + + + align:start position:0% +and then we switch to +one one thing that we can do with image + + align:start position:0% +one one thing that we can do with image + + + align:start position:0% +one one thing that we can do with image +brightness measurements which is the + + align:start position:0% +brightness measurements which is the + + + align:start position:0% +brightness measurements which is the +other half of image formation + + align:start position:0% +other half of image formation + + + align:start position:0% +other half of image formation +and in particular + + align:start position:0% +and in particular + + + align:start position:0% +and in particular +we're looking at shape from shading + + align:start position:0% +we're looking at shape from shading + + + align:start position:0% +we're looking at shape from shading +and so far we've + + align:start position:0% +and so far we've + + + align:start position:0% +and so far we've +solved the problem for very particular + + align:start position:0% +solved the problem for very particular + + + align:start position:0% +solved the problem for very particular +case + + align:start position:0% +case + + + align:start position:0% +case +which is the + + align:start position:0% + + + + align:start position:0% + +hapka model of surface reflectance + + align:start position:0% +hapka model of surface reflectance + + + align:start position:0% +hapka model of surface reflectance +and + + align:start position:0% + + + + align:start position:0% + +at the core of all of it is + + align:start position:0% +at the core of all of it is + + + align:start position:0% +at the core of all of it is +the image irradiance equation + + align:start position:0% + + + + align:start position:0% + +which basically says the + + align:start position:0% +which basically says the + + + align:start position:0% +which basically says the +brightness at some point in the image + + align:start position:0% +brightness at some point in the image + + + align:start position:0% +brightness at some point in the image +is the reflectance map + + align:start position:0% +is the reflectance map + + + align:start position:0% +is the reflectance map +corresponding to that surface + + align:start position:0% +corresponding to that surface + + + align:start position:0% +corresponding to that surface +orientation so here we're focusing on + + align:start position:0% +orientation so here we're focusing on + + + align:start position:0% +orientation so here we're focusing on +the + + align:start position:0% + + + + align:start position:0% + +dependence of brightness on surface + + align:start position:0% +dependence of brightness on surface + + + align:start position:0% +dependence of brightness on surface +orientation and as we mentioned it + + align:start position:0% +orientation and as we mentioned it + + + align:start position:0% +orientation and as we mentioned it +depends on illumination + + align:start position:0% +depends on illumination + + + align:start position:0% +depends on illumination +it depends on + + align:start position:0% +it depends on + + + align:start position:0% +it depends on +surface + + align:start position:0% +surface + + + align:start position:0% +surface +material that's where the reflectance + + align:start position:0% +material that's where the reflectance + + + align:start position:0% +material that's where the reflectance +map comes into it + + align:start position:0% +map comes into it + + + align:start position:0% +map comes into it +and it depends on + + align:start position:0% +and it depends on + + + align:start position:0% +and it depends on +the geometry in particular + + align:start position:0% + + + + align:start position:0% + +in particular surface orientation and + + align:start position:0% +in particular surface orientation and + + + align:start position:0% +in particular surface orientation and +it's a local thing so that's sort of + + align:start position:0% +it's a local thing so that's sort of + + + align:start position:0% +it's a local thing so that's sort of +good it means that the brightness + + align:start position:0% +good it means that the brightness + + + align:start position:0% +good it means that the brightness +measurement at a particular point in the + + align:start position:0% +measurement at a particular point in the + + + align:start position:0% +measurement at a particular point in the +image typically depends on what's + + align:start position:0% +image typically depends on what's + + + align:start position:0% +image typically depends on what's +happening at the corresponding point on + + align:start position:0% +happening at the corresponding point on + + + align:start position:0% +happening at the corresponding point on +on the object + + align:start position:0% +on the object + + + align:start position:0% +on the object +and the reflectance map was our way of + + align:start position:0% +and the reflectance map was our way of + + + align:start position:0% +and the reflectance map was our way of +sort of summarizing + + align:start position:0% +sort of summarizing + + + align:start position:0% +sort of summarizing +uh the detailed reflecting properties + + align:start position:0% +uh the detailed reflecting properties + + + align:start position:0% +uh the detailed reflecting properties +which in turn atomically + + align:start position:0% +which in turn atomically + + + align:start position:0% +which in turn atomically +are + + align:start position:0% +are + + + align:start position:0% +are +reflected in the brdf + + align:start position:0% +reflected in the brdf + + + align:start position:0% +reflected in the brdf +so we had the + + align:start position:0% +so we had the + + + align:start position:0% +so we had the +bi-directional reflectance distribution + + align:start position:0% +bi-directional reflectance distribution + + + align:start position:0% +bi-directional reflectance distribution +function + + align:start position:0% +function + + + align:start position:0% +function +but we pretty much + + align:start position:0% +but we pretty much + + + align:start position:0% +but we pretty much +built up on that to where we have a + + align:start position:0% +built up on that to where we have a + + + align:start position:0% +built up on that to where we have a +somewhat easier to manage + + align:start position:0% +somewhat easier to manage + + + align:start position:0% +somewhat easier to manage +reflectance map so the brdf depends on + + align:start position:0% +reflectance map so the brdf depends on + + + align:start position:0% +reflectance map so the brdf depends on +four parameters the reflectance map only + + align:start position:0% +four parameters the reflectance map only + + + align:start position:0% +four parameters the reflectance map only +depends on two but it's it's derived + + align:start position:0% +depends on two but it's it's derived + + + align:start position:0% +depends on two but it's it's derived +it's built on top of the the brdf + + align:start position:0% +it's built on top of the the brdf + + + align:start position:0% +it's built on top of the the brdf +okay um + + align:start position:0% +okay um + + + align:start position:0% +okay um +so + + align:start position:0% +so + + + align:start position:0% +so +we looked at a particular case + + align:start position:0% +we looked at a particular case + + + align:start position:0% +we looked at a particular case +which is that of + + align:start position:0% +which is that of + + + align:start position:0% +which is that of +reflecting properties of the + + align:start position:0% +reflecting properties of the + + + align:start position:0% +reflecting properties of the +moon the mara of mario of the moon and + + align:start position:0% +moon the mara of mario of the moon and + + + align:start position:0% +moon the mara of mario of the moon and +the + + align:start position:0% +the + + + align:start position:0% +the +rocky + + align:start position:0% +rocky + + + align:start position:0% +rocky +other rocky planets + + align:start position:0% +other rocky planets + + + align:start position:0% +other rocky planets +and in that case + + align:start position:0% +and in that case + + + align:start position:0% +and in that case +we found that we could solve this + + align:start position:0% +we found that we could solve this + + + align:start position:0% +we found that we could solve this +problem in a particular direction + + align:start position:0% + + + + align:start position:0% + +so in in + + align:start position:0% +so in in + + + align:start position:0% +so in in +case of the moon + + align:start position:0% +case of the moon + + + align:start position:0% +case of the moon +um + + align:start position:0% +um + + + align:start position:0% +um +if we take the ecliptic plane + + align:start position:0% +if we take the ecliptic plane + + + align:start position:0% +if we take the ecliptic plane +then that's the direction along which we + + align:start position:0% +then that's the direction along which we + + + align:start position:0% +then that's the direction along which we +can actually determine the surface + + align:start position:0% +can actually determine the surface + + + align:start position:0% +can actually determine the surface +orientation + + align:start position:0% +orientation + + + align:start position:0% +orientation +so + + align:start position:0% + + + + align:start position:0% + +we can integrate out + + align:start position:0% + + + + align:start position:0% + +in certain direction and we can't + + align:start position:0% +in certain direction and we can't + + + align:start position:0% +in certain direction and we can't +integrate at all + + align:start position:0% +integrate at all + + + align:start position:0% +integrate at all +in the direction at right angles and i + + align:start position:0% +in the direction at right angles and i + + + align:start position:0% +in the direction at right angles and i +mean typically we'd be looking at some + + align:start position:0% +mean typically we'd be looking at some + + + align:start position:0% +mean typically we'd be looking at some +small patch + + align:start position:0% +small patch + + + align:start position:0% +small patch +but this gives us the idea of what + + align:start position:0% +but this gives us the idea of what + + + align:start position:0% +but this gives us the idea of what +directions we can perform this in and + + align:start position:0% +directions we can perform this in and + + + align:start position:0% +directions we can perform this in and +whatnot + + align:start position:0% +whatnot + + + align:start position:0% +whatnot +okay and + + align:start position:0% +okay and + + + align:start position:0% +okay and +what we ended up with is a set of + + align:start position:0% +what we ended up with is a set of + + + align:start position:0% +what we ended up with is a set of +equations + + align:start position:0% + + + + align:start position:0% + +that + + align:start position:0% +that + + + align:start position:0% +that +take us from point to point on the + + align:start position:0% +take us from point to point on the + + + align:start position:0% +take us from point to point on the +surface and first of all um + + align:start position:0% +surface and first of all um + + + align:start position:0% +surface and first of all um +x and y are varying in this way and i + + align:start position:0% +x and y are varying in this way and i + + + align:start position:0% +x and y are varying in this way and i +have to apologize i think maybe last + + align:start position:0% +have to apologize i think maybe last + + + align:start position:0% +have to apologize i think maybe last +time i ended up with i was reversed + + align:start position:0% +time i ended up with i was reversed + + + align:start position:0% +time i ended up with i was reversed +i had the first one being qs and ps + + align:start position:0% +i had the first one being qs and ps + + + align:start position:0% +i had the first one being qs and ps +and this corresponds to that angle of + + align:start position:0% +and this corresponds to that angle of + + + align:start position:0% +and this corresponds to that angle of +rotation where we rotated one coordinate + + align:start position:0% +rotation where we rotated one coordinate + + + align:start position:0% +rotation where we rotated one coordinate +system to the other + + align:start position:0% +system to the other + + + align:start position:0% +system to the other +and then what's uh + + align:start position:0% +and then what's uh + + + align:start position:0% +and then what's uh +the change in height + + align:start position:0% +the change in height + + + align:start position:0% +the change in height +uh well according to you know chain rule + + align:start position:0% + + + + align:start position:0% + +which sort of looks intimidating but + + align:start position:0% +which sort of looks intimidating but + + + align:start position:0% +which sort of looks intimidating but +it's just uh + + align:start position:0% +it's just uh + + + align:start position:0% +it's just uh +p times + + align:start position:0% +p times + + + align:start position:0% +p times +the derivative up here so we got um + + align:start position:0% + + + + align:start position:0% + +just uh + + align:start position:0% +just uh + + + align:start position:0% +just uh +p times ps or ps plus + + align:start position:0% +p times ps or ps plus + + + align:start position:0% +p times ps or ps plus +qsq + + align:start position:0% +qsq + + + align:start position:0% +qsq +okay so this + + align:start position:0% +okay so this + + + align:start position:0% +okay so this +is the rule we can use to take a small + + align:start position:0% +is the rule we can use to take a small + + + align:start position:0% +is the rule we can use to take a small +step + + align:start position:0% +step + + + align:start position:0% +step +uh and we we take a small step + + align:start position:0% +uh and we we take a small step + + + align:start position:0% +uh and we we take a small step +in the image + + align:start position:0% +in the image + + + align:start position:0% +in the image +based on that and that corresponds to a + + align:start position:0% +based on that and that corresponds to a + + + align:start position:0% +based on that and that corresponds to a +small step in height + + align:start position:0% +small step in height + + + align:start position:0% +small step in height +and + + align:start position:0% +and + + + align:start position:0% +and +forgot to mention it here but + + align:start position:0% +forgot to mention it here but + + + align:start position:0% +forgot to mention it here but +we're now assuming orthographic + + align:start position:0% +we're now assuming orthographic + + + align:start position:0% +we're now assuming orthographic +projection + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +that's sort of a point + + align:start position:0% +that's sort of a point + + + align:start position:0% +that's sort of a point +that's important which is that + + align:start position:0% +that's important which is that + + + align:start position:0% +that's important which is that +once we switch to dealing with + + align:start position:0% +once we switch to dealing with + + + align:start position:0% +once we switch to dealing with +brightness we switch to orthographic + + align:start position:0% +brightness we switch to orthographic + + + align:start position:0% +brightness we switch to orthographic +projection + + align:start position:0% +projection + + + align:start position:0% +projection +why well because it makes everything + + align:start position:0% +why well because it makes everything + + + align:start position:0% +why well because it makes everything +much easier all of this can be done with + + align:start position:0% +much easier all of this can be done with + + + align:start position:0% +much easier all of this can be done with +perspective projection and it originally + + align:start position:0% +perspective projection and it originally + + + align:start position:0% +perspective projection and it originally +was but the math gets messy + + align:start position:0% +was but the math gets messy + + + align:start position:0% +was but the math gets messy +and so uh the thing to remember is that + + align:start position:0% +and so uh the thing to remember is that + + + align:start position:0% +and so uh the thing to remember is that +you know pretending we have a + + align:start position:0% +you know pretending we have a + + + align:start position:0% +you know pretending we have a +telecentric lens we talked about + + align:start position:0% +telecentric lens we talked about + + + align:start position:0% +telecentric lens we talked about +telecentric lenses and uh using a + + align:start position:0% +telecentric lenses and uh using a + + + align:start position:0% +telecentric lenses and uh using a +orthographic projection is it + + align:start position:0% +orthographic projection is it + + + align:start position:0% +orthographic projection is it +corresponds to being very far away + + align:start position:0% +corresponds to being very far away + + + align:start position:0% +corresponds to being very far away +as we are when we're looking at the moon + + align:start position:0% +as we are when we're looking at the moon + + + align:start position:0% +as we are when we're looking at the moon +and the light source is very far away + + align:start position:0% +and the light source is very far away + + + align:start position:0% +and the light source is very far away +and we have a very small visual angle + + align:start position:0% +and we have a very small visual angle + + + align:start position:0% +and we have a very small visual angle +and it simplifies things it's just like + + align:start position:0% +and it simplifies things it's just like + + + align:start position:0% +and it simplifies things it's just like +lambertian you know + + align:start position:0% +lambertian you know + + + align:start position:0% +lambertian you know +it's not that these methods are + + align:start position:0% +it's not that these methods are + + + align:start position:0% +it's not that these methods are +restricted to lambertian well in fact + + align:start position:0% +restricted to lambertian well in fact + + + align:start position:0% +restricted to lambertian well in fact +we're talking about non-laboration here + + align:start position:0% +we're talking about non-laboration here + + + align:start position:0% +we're talking about non-laboration here +um it's just that uh you can do some + + align:start position:0% +um it's just that uh you can do some + + + align:start position:0% +um it's just that uh you can do some +interesting things if you make that uh + + align:start position:0% +interesting things if you make that uh + + + align:start position:0% +interesting things if you make that uh +assumption + + align:start position:0% +assumption + + + align:start position:0% +assumption +and then generalize from there + + align:start position:0% + + + + align:start position:0% + +okay so + + align:start position:0% +okay so + + + align:start position:0% +okay so +that's the rule + + align:start position:0% +that's the rule + + + align:start position:0% +that's the rule +and basically we have three ordinary + + align:start position:0% +and basically we have three ordinary + + + align:start position:0% +and basically we have three ordinary +differential equations + + align:start position:0% + + + + align:start position:0% + +that we're going to solve numerically + + align:start position:0% +that we're going to solve numerically + + + align:start position:0% +that we're going to solve numerically +and we don't need very sophisticated + + align:start position:0% +and we don't need very sophisticated + + + align:start position:0% +and we don't need very sophisticated +methods like you know eighth order range + + align:start position:0% +methods like you know eighth order range + + + align:start position:0% +methods like you know eighth order range +cutter or something we're just going to + + align:start position:0% +cutter or something we're just going to + + + align:start position:0% +cutter or something we're just going to +do + + align:start position:0% +do + + + align:start position:0% +do +forward euler or in other words + + align:start position:0% +forward euler or in other words + + + align:start position:0% +forward euler or in other words +if you have the slope and you have a + + align:start position:0% +if you have the slope and you have a + + + align:start position:0% +if you have the slope and you have a +step size you just multiply the slope by + + align:start position:0% +step size you just multiply the slope by + + + align:start position:0% +step size you just multiply the slope by +the step size to see how much higher + + align:start position:0% +the step size to see how much higher + + + align:start position:0% +the step size to see how much higher +you've gone come so + + align:start position:0% +you've gone come so + + + align:start position:0% +you've gone come so +that that's the method we're going to + + align:start position:0% +that that's the method we're going to + + + align:start position:0% +that that's the method we're going to +use and of course it's not terribly + + align:start position:0% +use and of course it's not terribly + + + align:start position:0% +use and of course it's not terribly +accurate but + + align:start position:0% +accurate but + + + align:start position:0% +accurate but +if we make the steps small enough it's + + align:start position:0% +if we make the steps small enough it's + + + align:start position:0% +if we make the steps small enough it's +it's good enough + + align:start position:0% +it's good enough + + + align:start position:0% +it's good enough +and the measurements we're dealing with + + align:start position:0% +and the measurements we're dealing with + + + align:start position:0% +and the measurements we're dealing with +are themselves noisy so it doesn't make + + align:start position:0% +are themselves noisy so it doesn't make + + + align:start position:0% +are themselves noisy so it doesn't make +sense to you know apply a method that's + + align:start position:0% +sense to you know apply a method that's + + + align:start position:0% +sense to you know apply a method that's +good to + + align:start position:0% +good to + + + align:start position:0% +good to +12 decimal places when we start off with + + align:start position:0% +12 decimal places when we start off with + + + align:start position:0% +12 decimal places when we start off with +things based on image brightness + + align:start position:0% +things based on image brightness + + + align:start position:0% +things based on image brightness +measurements + + align:start position:0% +measurements + + + align:start position:0% +measurements +okay + + align:start position:0% +okay + + + align:start position:0% +okay +now + + align:start position:0% +now + + + align:start position:0% +now +how do we employ this well we need to + + align:start position:0% +how do we employ this well we need to + + + align:start position:0% +how do we employ this well we need to +tie it to brightness + + align:start position:0% +tie it to brightness + + + align:start position:0% +tie it to brightness +so somehow brightness has to feed into + + align:start position:0% +so somehow brightness has to feed into + + + align:start position:0% +so somehow brightness has to feed into +this this equation + + align:start position:0% +this this equation + + + align:start position:0% +this this equation +well + + align:start position:0% +well + + + align:start position:0% +well +for the hapka type surface we have + + align:start position:0% + + + + align:start position:0% + +we have this kind of dependence or + + align:start position:0% +we have this kind of dependence or + + + align:start position:0% +we have this kind of dependence or +actually it was cosine + + align:start position:0% +actually it was cosine + + + align:start position:0% +actually it was cosine +theta + + align:start position:0% + + + + align:start position:0% + +and + + align:start position:0% +and + + + align:start position:0% +and +in our + + align:start position:0% +in our + + + align:start position:0% +in our +arrangement for orthographic projection + + align:start position:0% +arrangement for orthographic projection + + + align:start position:0% +arrangement for orthographic projection +it's very convenient to have the viewer + + align:start position:0% +it's very convenient to have the viewer + + + align:start position:0% +it's very convenient to have the viewer +up along the z axis so + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and then we can plug in + + align:start position:0% +and then we can plug in + + + align:start position:0% +and then we can plug in +in terms of p and q + + align:start position:0% +in terms of p and q + + + align:start position:0% +in terms of p and q +so that's in terms of angles and in + + align:start position:0% +so that's in terms of angles and in + + + align:start position:0% +so that's in terms of angles and in +terms of + + align:start position:0% +terms of + + + align:start position:0% +terms of +unit normals + + align:start position:0% +unit normals + + + align:start position:0% +unit normals +but + + align:start position:0% +but + + + align:start position:0% +but +we we would like to express it in terms + + align:start position:0% +we we would like to express it in terms + + + align:start position:0% +we we would like to express it in terms +of p and q + + align:start position:0% +of p and q + + + align:start position:0% +of p and q +and then you remember that n dot s came + + align:start position:0% +and then you remember that n dot s came + + + align:start position:0% +and then you remember that n dot s came +out to be + + align:start position:0% + + + + align:start position:0% + +this thing + + align:start position:0% + + + + align:start position:0% + +and let's see we're going to take the + + align:start position:0% +and let's see we're going to take the + + + align:start position:0% +and let's see we're going to take the +square root of that + + align:start position:0% +square root of that + + + align:start position:0% +square root of that +and then we're going to divide it by + + align:start position:0% +and then we're going to divide it by + + + align:start position:0% +and then we're going to divide it by +n dot v or where v is the same as z so + + align:start position:0% +n dot v or where v is the same as z so + + + align:start position:0% +n dot v or where v is the same as z so +that's n dot z so that's one over + + align:start position:0% + + + + align:start position:0% + +and that conveniently cancels out + + align:start position:0% +and that conveniently cancels out + + + align:start position:0% +and that conveniently cancels out +so so we're in the end up with that so + + align:start position:0% +so so we're in the end up with that so + + + align:start position:0% +so so we're in the end up with that so +this is our r of p and q + + align:start position:0% + + + + align:start position:0% + +and by the um our assumption here about + + align:start position:0% +and by the um our assumption here about + + + align:start position:0% +and by the um our assumption here about +the image of radiance equation that's e + + align:start position:0% +the image of radiance equation that's e + + + align:start position:0% +the image of radiance equation that's e +of x and y + + align:start position:0% + + + + align:start position:0% + +so we can write + + align:start position:0% +so we can write + + + align:start position:0% +so we can write +e of x and y is this thing + + align:start position:0% +e of x and y is this thing + + + align:start position:0% +e of x and y is this thing +and + + align:start position:0% +and + + + align:start position:0% +and +you can see the term we're looking for + + align:start position:0% +you can see the term we're looking for + + + align:start position:0% +you can see the term we're looking for +is right in here p s p plus q qsq + + align:start position:0% +is right in here p s p plus q qsq + + + align:start position:0% +is right in here p s p plus q qsq +so we need to square + + align:start position:0% +so we need to square + + + align:start position:0% +so we need to square +the whole thing get rid of the square + + align:start position:0% +the whole thing get rid of the square + + + align:start position:0% +the whole thing get rid of the square +root and then multiply through by rs and + + align:start position:0% +root and then multiply through by rs and + + + align:start position:0% +root and then multiply through by rs and +subtract the 1. so we end up with um + + align:start position:0% + + + + align:start position:0% + +okay so for this particular surface + + align:start position:0% +okay so for this particular surface + + + align:start position:0% +okay so for this particular surface +there's a direct relationship between + + align:start position:0% +there's a direct relationship between + + + align:start position:0% +there's a direct relationship between +the quantity we can measure uh e + + align:start position:0% +the quantity we can measure uh e + + + align:start position:0% +the quantity we can measure uh e +and the thing we need + + align:start position:0% +and the thing we need + + + align:start position:0% +and the thing we need +to continue the solution + + align:start position:0% +to continue the solution + + + align:start position:0% +to continue the solution +right so + + align:start position:0% +right so + + + align:start position:0% +right so +we are what's r s well r s is just um + + align:start position:0% + + + + align:start position:0% + +dependent on the source position it's a + + align:start position:0% +dependent on the source position it's a + + + align:start position:0% +dependent on the source position it's a +constant + + align:start position:0% +constant + + + align:start position:0% +constant +and it just avoids having to write that + + align:start position:0% +and it just avoids having to write that + + + align:start position:0% +and it just avoids having to write that +all the time + + align:start position:0% +all the time + + + align:start position:0% +all the time +so we just take the brightness we square + + align:start position:0% +so we just take the brightness we square + + + align:start position:0% +so we just take the brightness we square +it we multiply it by rs we subtract one + + align:start position:0% +it we multiply it by rs we subtract one + + + align:start position:0% +it we multiply it by rs we subtract one +and there's the derivative in the z + + align:start position:0% +and there's the derivative in the z + + + align:start position:0% +and there's the derivative in the z +direction and that's it we just march + + align:start position:0% +direction and that's it we just march + + + align:start position:0% +direction and that's it we just march +along + + align:start position:0% +along + + + align:start position:0% +along +you know from one point to the next + + align:start position:0% +you know from one point to the next + + + align:start position:0% +you know from one point to the next +adjusting + + align:start position:0% +adjusting + + + align:start position:0% +adjusting +x y and z as we go and at each point we + + align:start position:0% +x y and z as we go and at each point we + + + align:start position:0% +x y and z as we go and at each point we +do we know the surface orientation + + align:start position:0% +do we know the surface orientation + + + align:start position:0% +do we know the surface orientation +wells a bit of it + + align:start position:0% +wells a bit of it + + + align:start position:0% +wells a bit of it +we know the slope in in that direction i + + align:start position:0% +we know the slope in in that direction i + + + align:start position:0% +we know the slope in in that direction i +mean that's what we're exploiting + + align:start position:0% +mean that's what we're exploiting + + + align:start position:0% +mean that's what we're exploiting +but as we indicated we don't know + + align:start position:0% +but as we indicated we don't know + + + align:start position:0% +but as we indicated we don't know +anything about the slope in the other + + align:start position:0% +anything about the slope in the other + + + align:start position:0% +anything about the slope in the other +direction so so no we don't don't know + + align:start position:0% +direction so so no we don't don't know + + + align:start position:0% +direction so so no we don't don't know +the + + align:start position:0% +the + + + align:start position:0% +the +surface orientation + + align:start position:0% +surface orientation + + + align:start position:0% +surface orientation +based on this and we need something else + + align:start position:0% +based on this and we need something else + + + align:start position:0% +based on this and we need something else +to do that + + align:start position:0% + + + + align:start position:0% + +now + + align:start position:0% +now + + + align:start position:0% +now +since each of these profiles is going to + + align:start position:0% +since each of these profiles is going to + + + align:start position:0% +since each of these profiles is going to +be independent + + align:start position:0% +be independent + + + align:start position:0% +be independent +to actually get z as a function of x and + + align:start position:0% +to actually get z as a function of x and + + + align:start position:0% +to actually get z as a function of x and +y in a real description of the surface + + align:start position:0% +y in a real description of the surface + + + align:start position:0% +y in a real description of the surface +we need to somehow have initial + + align:start position:0% +we need to somehow have initial + + + align:start position:0% +we need to somehow have initial +condition + + align:start position:0% +condition + + + align:start position:0% +condition +for these differential equations + + align:start position:0% +for these differential equations + + + align:start position:0% +for these differential equations +so you know x and y + + align:start position:0% +so you know x and y + + + align:start position:0% +so you know x and y +well we pick some point in the image to + + align:start position:0% +well we pick some point in the image to + + + align:start position:0% +well we pick some point in the image to +start + + align:start position:0% +start + + + align:start position:0% +start +but what about z + + align:start position:0% +but what about z + + + align:start position:0% +but what about z +well under our assumption of + + align:start position:0% +well under our assumption of + + + align:start position:0% +well under our assumption of +this + + align:start position:0% +this + + + align:start position:0% +this +image formation model + + align:start position:0% +image formation model + + + align:start position:0% +image formation model +there is no dependence on z the + + align:start position:0% +there is no dependence on z the + + + align:start position:0% +there is no dependence on z the +dependence is on the slope of z + + align:start position:0% +dependence is on the slope of z + + + align:start position:0% +dependence is on the slope of z +right so + + align:start position:0% +right so + + + align:start position:0% +right so +actually if we moved + + align:start position:0% +actually if we moved + + + align:start position:0% +actually if we moved +this + + align:start position:0% +this + + + align:start position:0% +this +object in the z direction its image + + align:start position:0% +object in the z direction its image + + + align:start position:0% +object in the z direction its image +wouldn't change well under perspective + + align:start position:0% +wouldn't change well under perspective + + + align:start position:0% +wouldn't change well under perspective +projection it would change in size + + align:start position:0% +projection it would change in size + + + align:start position:0% +projection it would change in size +but we're not + + align:start position:0% +but we're not + + + align:start position:0% +but we're not +dealing with perspective projection + + align:start position:0% +dealing with perspective projection + + + align:start position:0% +dealing with perspective projection +we're dealing with orthographic + + align:start position:0% +we're dealing with orthographic + + + align:start position:0% +we're dealing with orthographic +projection + + align:start position:0% +projection + + + align:start position:0% +projection +and so its size doesn't change so so + + align:start position:0% +and so its size doesn't change so so + + + align:start position:0% +and so its size doesn't change so so +there's an ambiguity + + align:start position:0% +there's an ambiguity + + + align:start position:0% +there's an ambiguity +so for each of those + + align:start position:0% +so for each of those + + + align:start position:0% +so for each of those +uh curves that we're computing + + align:start position:0% +uh curves that we're computing + + + align:start position:0% +uh curves that we're computing +we need an initial condition so actually + + align:start position:0% +we need an initial condition so actually + + + align:start position:0% +we need an initial condition so actually +we need an initial curve + + align:start position:0% + + + + align:start position:0% + +and so in 3d how do we do that well + + align:start position:0% +and so in 3d how do we do that well + + + align:start position:0% +and so in 3d how do we do that well +here's a way of + + align:start position:0% +here's a way of + + + align:start position:0% +here's a way of +defining a curve + + align:start position:0% +defining a curve + + + align:start position:0% +defining a curve +we have some parameter that varies along + + align:start position:0% +we have some parameter that varies along + + + align:start position:0% +we have some parameter that varies along +the curve could be arc length or some + + align:start position:0% +the curve could be arc length or some + + + align:start position:0% +the curve could be arc length or some +arbitrary parameter + + align:start position:0% +arbitrary parameter + + + align:start position:0% +arbitrary parameter +eta + + align:start position:0% +eta + + + align:start position:0% +eta +and for each eta we give a position in + + align:start position:0% +and for each eta we give a position in + + + align:start position:0% +and for each eta we give a position in +space x y and z + + align:start position:0% +space x y and z + + + align:start position:0% +space x y and z +and that's a curve and so that's our + + align:start position:0% +and that's a curve and so that's our + + + align:start position:0% +and that's a curve and so that's our +let's assume we have that initial curve + + align:start position:0% +let's assume we have that initial curve + + + align:start position:0% +let's assume we have that initial curve +so + + align:start position:0% +so + + + align:start position:0% +so +some sort of curve like this and then we + + align:start position:0% +some sort of curve like this and then we + + + align:start position:0% +some sort of curve like this and then we +can start at any point on that curve + + align:start position:0% +can start at any point on that curve + + + align:start position:0% +can start at any point on that curve +and integrate out those equations + + align:start position:0% +and integrate out those equations + + + align:start position:0% +and integrate out those equations +numerically + + align:start position:0% + + + + align:start position:0% + +and + + align:start position:0% + + + + align:start position:0% + +there's our surface + + align:start position:0% +there's our surface + + + align:start position:0% +there's our surface +and as we mentioned + + align:start position:0% +and as we mentioned + + + align:start position:0% +and as we mentioned +we can actually go in both directions + + align:start position:0% +we can actually go in both directions + + + align:start position:0% +we can actually go in both directions +from the initial curve + + align:start position:0% +from the initial curve + + + align:start position:0% +from the initial curve +and so + + align:start position:0% +and so + + + align:start position:0% +and so +we end up with + + align:start position:0% +we end up with + + + align:start position:0% +we end up with +z of x y or actually z of + + align:start position:0% +z of x y or actually z of + + + align:start position:0% +z of x y or actually z of +eta and psi + + align:start position:0% +eta and psi + + + align:start position:0% +eta and psi +right because the way we've + + align:start position:0% +right because the way we've + + + align:start position:0% +right because the way we've +parameterized it is + + align:start position:0% +parameterized it is + + + align:start position:0% +parameterized it is +one parameter + + align:start position:0% +one parameter + + + align:start position:0% +one parameter +goes along the + + align:start position:0% +goes along the + + + align:start position:0% +goes along the +curve + + align:start position:0% +curve + + + align:start position:0% +curve +the other parameter goes along the + + align:start position:0% +the other parameter goes along the + + + align:start position:0% +the other parameter goes along the +initial curve so + + align:start position:0% +initial curve so + + + align:start position:0% +initial curve so +so it's the surface in 3d and it takes + + align:start position:0% +so it's the surface in 3d and it takes + + + align:start position:0% +so it's the surface in 3d and it takes +two parameters to parameterize that so + + align:start position:0% +two parameters to parameterize that so + + + align:start position:0% +two parameters to parameterize that so +so that's + + align:start position:0% + + + + align:start position:0% + +straightforward i hope + + align:start position:0% +straightforward i hope + + + align:start position:0% +straightforward i hope +that in that particular case we + + align:start position:0% +that in that particular case we + + + align:start position:0% +that in that particular case we +have some very special properties one of + + align:start position:0% +have some very special properties one of + + + align:start position:0% +have some very special properties one of +them is that we can locally determine + + align:start position:0% +them is that we can locally determine + + + align:start position:0% +them is that we can locally determine +the slope in a particular direction and + + align:start position:0% +the slope in a particular direction and + + + align:start position:0% +the slope in a particular direction and +that means of course we can go in that + + align:start position:0% +that means of course we can go in that + + + align:start position:0% +that means of course we can go in that +direction and and build up a curve + + align:start position:0% +direction and and build up a curve + + + align:start position:0% +direction and and build up a curve +and that's + + align:start position:0% +and that's + + + align:start position:0% +and that's +not going to be true in the general case + + align:start position:0% +not going to be true in the general case + + + align:start position:0% +not going to be true in the general case +so + + align:start position:0% +so + + + align:start position:0% +so +what do we do about + + align:start position:0% +what do we do about + + + align:start position:0% +what do we do about +about the general case + + align:start position:0% + + + + align:start position:0% + +so we'll still start off with + + align:start position:0% + + + + align:start position:0% + +our image irradiance equation + + align:start position:0% + + + + align:start position:0% + +which says that the brightness at a + + align:start position:0% +which says that the brightness at a + + + align:start position:0% +which says that the brightness at a +particular point in the image + + align:start position:0% +particular point in the image + + + align:start position:0% +particular point in the image +is dependent on the surface orientation + + align:start position:0% +is dependent on the surface orientation + + + align:start position:0% +is dependent on the surface orientation +at the corresponding point point on the + + align:start position:0% +at the corresponding point point on the + + + align:start position:0% +at the corresponding point point on the +object and we'll sort of try and follow + + align:start position:0% +object and we'll sort of try and follow + + + align:start position:0% +object and we'll sort of try and follow +this model here so + + align:start position:0% +this model here so + + + align:start position:0% +this model here so +you know suppose we're at some + + align:start position:0% +you know suppose we're at some + + + align:start position:0% +you know suppose we're at some +particular point x y z + + align:start position:0% +particular point x y z + + + align:start position:0% +particular point x y z +and then we take a small step + + align:start position:0% + + + + align:start position:0% + +and in the image + + align:start position:0% + + + + align:start position:0% + +let's suppose the steps + + align:start position:0% +let's suppose the steps + + + align:start position:0% +let's suppose the steps +size is delta x delta y and + + align:start position:0% +size is delta x delta y and + + + align:start position:0% +size is delta x delta y and +for the moment we won't say which + + align:start position:0% +for the moment we won't say which + + + align:start position:0% +for the moment we won't say which +direction we're going we'll just + + align:start position:0% +direction we're going we'll just + + + align:start position:0% +direction we're going we'll just +leave that + + align:start position:0% +leave that + + + align:start position:0% +leave that +unknown + + align:start position:0% +unknown + + + align:start position:0% +unknown +and + + align:start position:0% +and + + + align:start position:0% +and +to construct the solution what we need + + align:start position:0% +to construct the solution what we need + + + align:start position:0% +to construct the solution what we need +to know is you know what's z how is z + + align:start position:0% +to know is you know what's z how is z + + + align:start position:0% +to know is you know what's z how is z +going to change + + align:start position:0% +going to change + + + align:start position:0% +going to change +and so of course + + align:start position:0% + + + + align:start position:0% + +um we have that relationship the change + + align:start position:0% +um we have that relationship the change + + + align:start position:0% +um we have that relationship the change +in z is dz dx times delta x plus dz dy + + align:start position:0% +in z is dz dx times delta x plus dz dy + + + align:start position:0% +in z is dz dx times delta x plus dz dy +times delta y + + align:start position:0% +times delta y + + + align:start position:0% +times delta y +and so + + align:start position:0% +and so + + + align:start position:0% +and so +we can calculate the change in height + + align:start position:0% +we can calculate the change in height + + + align:start position:0% +we can calculate the change in height +if we know p and q + + align:start position:0% + + + + align:start position:0% + +and suppose we know p and q then we're + + align:start position:0% +and suppose we know p and q then we're + + + align:start position:0% +and suppose we know p and q then we're +at a new point on the surface and we can + + align:start position:0% +at a new point on the surface and we can + + + align:start position:0% +at a new point on the surface and we can +repeat we + + align:start position:0% +repeat we + + + align:start position:0% +repeat we +take a small step in x and y and + + align:start position:0% +take a small step in x and y and + + + align:start position:0% +take a small step in x and y and +now over here we kept on going in in a + + align:start position:0% +now over here we kept on going in in a + + + align:start position:0% +now over here we kept on going in in a +certain direction that + + align:start position:0% +certain direction that + + + align:start position:0% +certain direction that +in this case we may need to + + align:start position:0% +in this case we may need to + + + align:start position:0% +in this case we may need to +choose a direction in some particular + + align:start position:0% +choose a direction in some particular + + + align:start position:0% +choose a direction in some particular +way but + + align:start position:0% +way but + + + align:start position:0% +way but +we need to know p and q + + align:start position:0% +we need to know p and q + + + align:start position:0% +we need to know p and q +okay well uh we can assume that we start + + align:start position:0% +okay well uh we can assume that we start + + + align:start position:0% +okay well uh we can assume that we start +off not only knowing x y and z but also + + align:start position:0% +off not only knowing x y and z but also + + + align:start position:0% +off not only knowing x y and z but also +the surface orientation + + align:start position:0% +the surface orientation + + + align:start position:0% +the surface orientation +so we could have + + align:start position:0% +so we could have + + + align:start position:0% +so we could have +you know x y and z and p and q + + align:start position:0% +you know x y and z and p and q + + + align:start position:0% +you know x y and z and p and q +but then how do we update every step we + + align:start position:0% +but then how do we update every step we + + + align:start position:0% +but then how do we update every step we +need to + + align:start position:0% +need to + + + align:start position:0% +need to +update p and q + + align:start position:0% + + + + align:start position:0% + +so here we have updates rules for x y + + align:start position:0% +so here we have updates rules for x y + + + align:start position:0% +so here we have updates rules for x y +and z for x and y you know we're the + + align:start position:0% +and z for x and y you know we're the + + + align:start position:0% +and z for x and y you know we're the +ones controlling the step + + align:start position:0% +ones controlling the step + + + align:start position:0% +ones controlling the step +and then z + + align:start position:0% +and then z + + + align:start position:0% +and then z +the change in z is given by this + + align:start position:0% +the change in z is given by this + + + align:start position:0% +the change in z is given by this +equation + + align:start position:0% +equation + + + align:start position:0% +equation +so um well we can use the same chain + + align:start position:0% +so um well we can use the same chain + + + align:start position:0% +so um well we can use the same chain +rule trick we can say that delta p is p + + align:start position:0% +rule trick we can say that delta p is p + + + align:start position:0% +rule trick we can say that delta p is p +sub x delta x plus + + align:start position:0% +sub x delta x plus + + + align:start position:0% +sub x delta x plus +p sub y delta y + + align:start position:0% +p sub y delta y + + + align:start position:0% +p sub y delta y +and delta q is q sub x delta x plus + + align:start position:0% +and delta q is q sub x delta x plus + + + align:start position:0% +and delta q is q sub x delta x plus +q sub y delta y + + align:start position:0% +q sub y delta y + + + align:start position:0% +q sub y delta y +so that + + align:start position:0% +so that + + + align:start position:0% +so that +we can update p and q as we go along so + + align:start position:0% +we can update p and q as we go along so + + + align:start position:0% +we can update p and q as we go along so +we're not only updating x y and z but + + align:start position:0% +we're not only updating x y and z but + + + align:start position:0% +we're not only updating x y and z but +we're also updating p and q so this is + + align:start position:0% +we're also updating p and q so this is + + + align:start position:0% +we're also updating p and q so this is +kind of interesting before we had a + + align:start position:0% +kind of interesting before we had a + + + align:start position:0% +kind of interesting before we had a +curve in space we were tracing out x y + + align:start position:0% +curve in space we were tracing out x y + + + align:start position:0% +curve in space we were tracing out x y +and z + + align:start position:0% +and z + + + align:start position:0% +and z +as we construct the solution now we've + + align:start position:0% +as we construct the solution now we've + + + align:start position:0% +as we construct the solution now we've +got more because at every point we know + + align:start position:0% +got more because at every point we know + + + align:start position:0% +got more because at every point we know +p and q + + align:start position:0% +p and q + + + align:start position:0% +p and q +which means we know the surface + + align:start position:0% +which means we know the surface + + + align:start position:0% +which means we know the surface +orientation + + align:start position:0% +orientation + + + align:start position:0% +orientation +so what we're really constructing now is + + align:start position:0% +so what we're really constructing now is + + + align:start position:0% +so what we're really constructing now is +a strip + + align:start position:0% + + + + align:start position:0% + +well not + + align:start position:0% +well not + + + align:start position:0% +well not +not very elegant + + align:start position:0% + + + + align:start position:0% + +and this is called a characteristic + + align:start position:0% +and this is called a characteristic + + + align:start position:0% +and this is called a characteristic +strip characteristic of that + + align:start position:0% +strip characteristic of that + + + align:start position:0% +strip characteristic of that +differential equation and + + align:start position:0% +differential equation and + + + align:start position:0% +differential equation and +that means that + + align:start position:0% +that means that + + + align:start position:0% +that means that +you know we're carrying a long surface + + align:start position:0% +you know we're carrying a long surface + + + align:start position:0% +you know we're carrying a long surface +orientation so if i wanted to i could + + align:start position:0% +orientation so if i wanted to i could + + + align:start position:0% +orientation so if i wanted to i could +erect + + align:start position:0% +erect + + + align:start position:0% +erect +surface normals as as i go along so + + align:start position:0% +surface normals as as i go along so + + + align:start position:0% +surface normals as as i go along so +that's obviously more information than + + align:start position:0% +that's obviously more information than + + + align:start position:0% +that's obviously more information than +just a curve + + align:start position:0% + + + + align:start position:0% + +okay so that's what we'll be doing we'll + + align:start position:0% +okay so that's what we'll be doing we'll + + + align:start position:0% +okay so that's what we'll be doing we'll +update not just x y and z but p and q + + align:start position:0% +update not just x y and z but p and q + + + align:start position:0% +update not just x y and z but p and q +which we didn't have to do over here + + align:start position:0% +which we didn't have to do over here + + + align:start position:0% +which we didn't have to do over here +because of the particular + + align:start position:0% +because of the particular + + + align:start position:0% +because of the particular +properties of of the hapka type model + + align:start position:0% +properties of of the hapka type model + + + align:start position:0% +properties of of the hapka type model +okay but + + align:start position:0% +okay but + + + align:start position:0% +okay but +how do we do this well in order to + + align:start position:0% +how do we do this well in order to + + + align:start position:0% +how do we do this well in order to +update we need to know p x p y + + align:start position:0% +update we need to know p x p y + + + align:start position:0% +update we need to know p x p y +q x and q y and + + align:start position:0% +q x and q y and + + + align:start position:0% +q x and q y and +we can write this another way + + align:start position:0% + + + + align:start position:0% + +in matrix form so the two two linear + + align:start position:0% +in matrix form so the two two linear + + + align:start position:0% +in matrix form so the two two linear +equations two unknowns we can write it + + align:start position:0% +equations two unknowns we can write it + + + align:start position:0% +equations two unknowns we can write it +with a two by two matrix + + align:start position:0% +with a two by two matrix + + + align:start position:0% +with a two by two matrix +and so what are these are are s and t so + + align:start position:0% +and so what are these are are s and t so + + + align:start position:0% +and so what are these are are s and t so +r + + align:start position:0% +r + + + align:start position:0% +r +is p sub x which is really uh + + align:start position:0% +is p sub x which is really uh + + + align:start position:0% +is p sub x which is really uh +you know the second derivative of z + + align:start position:0% +you know the second derivative of z + + + align:start position:0% +you know the second derivative of z +s is p sub y + + align:start position:0% +s is p sub y + + + align:start position:0% +s is p sub y +which is q sub x which is this one + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +the + + align:start position:0% +the + + + align:start position:0% +the +quantities we need in order to use this + + align:start position:0% +quantities we need in order to use this + + + align:start position:0% +quantities we need in order to use this +update rule are the second partial + + align:start position:0% +update rule are the second partial + + + align:start position:0% +update rule are the second partial +derivatives of + + align:start position:0% +derivatives of + + + align:start position:0% +derivatives of +height + + align:start position:0% +height + + + align:start position:0% +height +and those are interesting because they + + align:start position:0% +and those are interesting because they + + + align:start position:0% +and those are interesting because they +correspond to curvature so the first + + align:start position:0% +correspond to curvature so the first + + + align:start position:0% +correspond to curvature so the first +derivative have to do with surface + + align:start position:0% +derivative have to do with surface + + + align:start position:0% +derivative have to do with surface +orientation and the second derivatives + + align:start position:0% +orientation and the second derivatives + + + align:start position:0% +orientation and the second derivatives +have to do with how quickly the + + align:start position:0% +have to do with how quickly the + + + align:start position:0% +have to do with how quickly the +orientation is changing and that of + + align:start position:0% +orientation is changing and that of + + + align:start position:0% +orientation is changing and that of +course is curvature and for + + align:start position:0% +course is curvature and for + + + align:start position:0% +course is curvature and for +a 3d surface curvature is a little bit + + align:start position:0% +a 3d surface curvature is a little bit + + + align:start position:0% +a 3d surface curvature is a little bit +more complicated than it is for say a + + align:start position:0% +more complicated than it is for say a + + + align:start position:0% +more complicated than it is for say a +curve in the plane + + align:start position:0% +curve in the plane + + + align:start position:0% +curve in the plane +and you need + + align:start position:0% +and you need + + + align:start position:0% +and you need +three numbers to describe it so for a + + align:start position:0% +three numbers to describe it so for a + + + align:start position:0% +three numbers to describe it so for a +curve in the plane you can just give the + + align:start position:0% +curve in the plane you can just give the + + + align:start position:0% +curve in the plane you can just give the +radius of curvature + + align:start position:0% +radius of curvature + + + align:start position:0% +radius of curvature +or the inverse of that which is called + + align:start position:0% +or the inverse of that which is called + + + align:start position:0% +or the inverse of that which is called +curvature just one number but for 3d + + align:start position:0% +curvature just one number but for 3d + + + align:start position:0% +curvature just one number but for 3d +surface it's a little bit more + + align:start position:0% +surface it's a little bit more + + + align:start position:0% +surface it's a little bit more +complicated and you need this whole + + align:start position:0% +complicated and you need this whole + + + align:start position:0% +complicated and you need this whole +matrix of + + align:start position:0% +matrix of + + + align:start position:0% +matrix of +second order derivatives and it's called + + align:start position:0% +second order derivatives and it's called + + + align:start position:0% +second order derivatives and it's called +the hessian matrix + + align:start position:0% +the hessian matrix + + + align:start position:0% +the hessian matrix +and in here i assume that + + align:start position:0% +and in here i assume that + + + align:start position:0% +and in here i assume that +you know the order of differentiation + + align:start position:0% +you know the order of differentiation + + + align:start position:0% +you know the order of differentiation +doesn't matter that z of x y is z of y x + + align:start position:0% +doesn't matter that z of x y is z of y x + + + align:start position:0% +doesn't matter that z of x y is z of y x +and that will be true for some + + align:start position:0% +and that will be true for some + + + align:start position:0% +and that will be true for some +reasonable surface + + align:start position:0% +reasonable surface + + + align:start position:0% +reasonable surface +won't specify the exact conditions for + + align:start position:0% +won't specify the exact conditions for + + + align:start position:0% +won't specify the exact conditions for +that + + align:start position:0% +that + + + align:start position:0% +that +and of course you can construct + + align:start position:0% +and of course you can construct + + + align:start position:0% +and of course you can construct +pathological things + + align:start position:0% +pathological things + + + align:start position:0% +pathological things +that don't satisfy that but + + align:start position:0% +that don't satisfy that but + + + align:start position:0% +that don't satisfy that but +you know those are mathematical + + align:start position:0% +you know those are mathematical + + + align:start position:0% +you know those are mathematical +curiosities rather than + + align:start position:0% +curiosities rather than + + + align:start position:0% +curiosities rather than +real surfaces that will + + align:start position:0% +real surfaces that will + + + align:start position:0% +real surfaces that will +meet in machine vision + + align:start position:0% +meet in machine vision + + + align:start position:0% +meet in machine vision +okay so that's the + + align:start position:0% +okay so that's the + + + align:start position:0% +okay so that's the +curvature matrix and so + + align:start position:0% +curvature matrix and so + + + align:start position:0% +curvature matrix and so +uh we if we know the steps and we know + + align:start position:0% +uh we if we know the steps and we know + + + align:start position:0% +uh we if we know the steps and we know +that matrix we can + + align:start position:0% +that matrix we can + + + align:start position:0% +that matrix we can +calculate the change in p and q + + align:start position:0% +calculate the change in p and q + + + align:start position:0% +calculate the change in p and q +and we can continue the solution + + align:start position:0% + + + + align:start position:0% + +well that kind of means that we should + + align:start position:0% +well that kind of means that we should + + + align:start position:0% +well that kind of means that we should +add r s and t + + align:start position:0% +add r s and t + + + align:start position:0% +add r s and t +to our menagerie of variables so we're + + align:start position:0% +to our menagerie of variables so we're + + + align:start position:0% +to our menagerie of variables so we're +going to carry along x y and z + + align:start position:0% +going to carry along x y and z + + + align:start position:0% +going to carry along x y and z +p and q + + align:start position:0% +p and q + + + align:start position:0% +p and q +r s and t + + align:start position:0% +r s and t + + + align:start position:0% +r s and t +and yeah we can do that now how do we + + align:start position:0% +and yeah we can do that now how do we + + + align:start position:0% +and yeah we can do that now how do we +update our s and t + + align:start position:0% +update our s and t + + + align:start position:0% +update our s and t +second derivatives well we use the third + + align:start position:0% +second derivatives well we use the third + + + align:start position:0% +second derivatives well we use the third +derivatives + + align:start position:0% +derivatives + + + align:start position:0% +derivatives +so i think you can see where this is + + align:start position:0% +so i think you can see where this is + + + align:start position:0% +so i think you can see where this is +going this is kind of + + align:start position:0% +going this is kind of + + + align:start position:0% +going this is kind of +continuing ad nauseam using higher and + + align:start position:0% +continuing ad nauseam using higher and + + + align:start position:0% +continuing ad nauseam using higher and +higher higher order derivatives + + align:start position:0% +higher higher order derivatives + + + align:start position:0% +higher higher order derivatives +and so that's probably uh not going to + + align:start position:0% +and so that's probably uh not going to + + + align:start position:0% +and so that's probably uh not going to +work in fact + + align:start position:0% +work in fact + + + align:start position:0% +work in fact +we end up with more unknowns + + align:start position:0% +we end up with more unknowns + + + align:start position:0% +we end up with more unknowns +you know here we've got before we didn't + + align:start position:0% +you know here we've got before we didn't + + + align:start position:0% +you know here we've got before we didn't +know p and q + + align:start position:0% +know p and q + + + align:start position:0% +know p and q +two unknowns now we don't know r s and t + + align:start position:0% +two unknowns now we don't know r s and t + + + align:start position:0% +two unknowns now we don't know r s and t +three unknowns so it's it's not going in + + align:start position:0% +three unknowns so it's it's not going in + + + align:start position:0% +three unknowns so it's it's not going in +in a good direction + + align:start position:0% +in a good direction + + + align:start position:0% +in a good direction +but what's sort of neat is that + + align:start position:0% +but what's sort of neat is that + + + align:start position:0% +but what's sort of neat is that +we haven't yet even used our image + + align:start position:0% +we haven't yet even used our image + + + align:start position:0% +we haven't yet even used our image +irradiance equation + + align:start position:0% +irradiance equation + + + align:start position:0% +irradiance equation +you know we haven't looked at the image + + align:start position:0% +you know we haven't looked at the image + + + align:start position:0% +you know we haven't looked at the image +so far we're just playing with + + align:start position:0% +so far we're just playing with + + + align:start position:0% +so far we're just playing with +derivatives so that that's obviously + + align:start position:0% +derivatives so that that's obviously + + + align:start position:0% +derivatives so that that's obviously +uh + + align:start position:0% +uh + + + align:start position:0% +uh +a flaw in our reasoning here we're only + + align:start position:0% +a flaw in our reasoning here we're only + + + align:start position:0% +a flaw in our reasoning here we're only +looking at the derivatives of z we're + + align:start position:0% +looking at the derivatives of z we're + + + align:start position:0% +looking at the derivatives of z we're +not uh using image brightness + + align:start position:0% +not uh using image brightness + + + align:start position:0% +not uh using image brightness +measurements at all so that doesn't make + + align:start position:0% +measurements at all so that doesn't make + + + align:start position:0% +measurements at all so that doesn't make +any sense so let's see what we can do + + align:start position:0% +any sense so let's see what we can do + + + align:start position:0% +any sense so let's see what we can do +with the + + align:start position:0% +with the + + + align:start position:0% +with the +image irradiance equation and in + + align:start position:0% +image irradiance equation and in + + + align:start position:0% +image irradiance equation and in +particular we're often interested in the + + align:start position:0% +particular we're often interested in the + + + align:start position:0% +particular we're often interested in the +brightness gradient so let's look at the + + align:start position:0% +brightness gradient so let's look at the + + + align:start position:0% +brightness gradient so let's look at the +brightness gradient + + align:start position:0% +brightness gradient + + + align:start position:0% +brightness gradient +so + + align:start position:0% +so + + + align:start position:0% +so +which way do i want to write this + + align:start position:0% + + + + align:start position:0% + +again by the chain rule + + align:start position:0% +again by the chain rule + + + align:start position:0% +again by the chain rule +uh well i get the derivative r r with + + align:start position:0% +uh well i get the derivative r r with + + + align:start position:0% +uh well i get the derivative r r with +respect to p + + align:start position:0% +respect to p + + + align:start position:0% +respect to p +times the dp dx + + align:start position:0% +times the dp dx + + + align:start position:0% +times the dp dx +plus r with respect to q times dq dx and + + align:start position:0% + + + + align:start position:0% + +and of course these are the very + + align:start position:0% +and of course these are the very + + + align:start position:0% +and of course these are the very +quantities that we've run into over here + + align:start position:0% +quantities that we've run into over here + + + align:start position:0% +quantities that we've run into over here +so this is what we call r + + align:start position:0% +so this is what we call r + + + align:start position:0% +so this is what we call r +this is s + + align:start position:0% +this is s + + + align:start position:0% +this is s +that's s and that's t + + align:start position:0% +that's s and that's t + + + align:start position:0% +that's s and that's t +so that's sort of an interesting analogy + + align:start position:0% +so that's sort of an interesting analogy + + + align:start position:0% +so that's sort of an interesting analogy +with with this we can write this in + + align:start position:0% +with with this we can write this in + + + align:start position:0% +with with this we can write this in +matrix vector form + + align:start position:0% + + + + align:start position:0% + +that's the same matrix + + align:start position:0% + + + + align:start position:0% + +so that matrix is important + + align:start position:0% +so that matrix is important + + + align:start position:0% +so that matrix is important +and it makes sense okay if you have a + + align:start position:0% +and it makes sense okay if you have a + + + align:start position:0% +and it makes sense okay if you have a +surface with constant surface + + align:start position:0% +surface with constant surface + + + align:start position:0% +surface with constant surface +orientation the image will be constant + + align:start position:0% +orientation the image will be constant + + + align:start position:0% +orientation the image will be constant +brightness in this model where + + align:start position:0% +brightness in this model where + + + align:start position:0% +brightness in this model where +brightness depends only on surface + + align:start position:0% +brightness depends only on surface + + + align:start position:0% +brightness depends only on surface +orientation + + align:start position:0% +orientation + + + align:start position:0% +orientation +if we are looking for gradient we're + + align:start position:0% +if we are looking for gradient we're + + + align:start position:0% +if we are looking for gradient we're +looking for changes in brightness and + + align:start position:0% +looking for changes in brightness and + + + align:start position:0% +looking for changes in brightness and +those are only going to happen if there + + align:start position:0% +those are only going to happen if there + + + align:start position:0% +those are only going to happen if there +changes in surface orientation changes + + align:start position:0% +changes in surface orientation changes + + + align:start position:0% +changes in surface orientation changes +in surface orientation correspond to + + align:start position:0% +in surface orientation correspond to + + + align:start position:0% +in surface orientation correspond to +curvature right so at one place i'm + + align:start position:0% +curvature right so at one place i'm + + + align:start position:0% +curvature right so at one place i'm +going downhill and then it's flat and + + align:start position:0% +going downhill and then it's flat and + + + align:start position:0% +going downhill and then it's flat and +then it's going uphill + + align:start position:0% +then it's going uphill + + + align:start position:0% +then it's going uphill +second derivative is non-zero + + align:start position:0% +second derivative is non-zero + + + align:start position:0% +second derivative is non-zero +so and exactly the second + + align:start position:0% +so and exactly the second + + + align:start position:0% +so and exactly the second +derivative matrix controls that that's + + align:start position:0% +derivative matrix controls that that's + + + align:start position:0% +derivative matrix controls that that's +the precise statement of how that all + + align:start position:0% +the precise statement of how that all + + + align:start position:0% +the precise statement of how that all +works + + align:start position:0% +works + + + align:start position:0% +works +well + + align:start position:0% +well + + + align:start position:0% +well +if we look at these two + + align:start position:0% +if we look at these two + + + align:start position:0% +if we look at these two +things just a post + + align:start position:0% +things just a post + + + align:start position:0% +things just a post +you know there's that common matrix h + + align:start position:0% +you know there's that common matrix h + + + align:start position:0% +you know there's that common matrix h +now if we could somehow figure out what + + align:start position:0% +now if we could somehow figure out what + + + align:start position:0% +now if we could somehow figure out what +h was + + align:start position:0% +h was + + + align:start position:0% +h was +we could just plug it in here and we + + align:start position:0% +we could just plug it in here and we + + + align:start position:0% +we could just plug it in here and we +would be + + align:start position:0% +would be + + + align:start position:0% +would be +golden we know you know we can + + align:start position:0% +golden we know you know we can + + + align:start position:0% +golden we know you know we can +implement this method because + + align:start position:0% +implement this method because + + + align:start position:0% +implement this method because +we take a small step in the image delta + + align:start position:0% +we take a small step in the image delta + + + align:start position:0% +we take a small step in the image delta +x delta y multiply by this matrix h and + + align:start position:0% +x delta y multiply by this matrix h and + + + align:start position:0% +x delta y multiply by this matrix h and +out comes the small change in p and q so + + align:start position:0% +out comes the small change in p and q so + + + align:start position:0% +out comes the small change in p and q so +we can have update rules for x y z and p + + align:start position:0% +we can have update rules for x y z and p + + + align:start position:0% +we can have update rules for x y z and p +and q and you know we're done + + align:start position:0% +and q and you know we're done + + + align:start position:0% +and q and you know we're done +so i guess the question is how do you + + align:start position:0% +so i guess the question is how do you + + + align:start position:0% +so i guess the question is how do you +solve this thing for for h + + align:start position:0% + + + + align:start position:0% + +so what have we got so so this we can + + align:start position:0% +so what have we got so so this we can + + + align:start position:0% +so what have we got so so this we can +get from the image + + align:start position:0% +get from the image + + + align:start position:0% +get from the image +the brightness gradient + + align:start position:0% +the brightness gradient + + + align:start position:0% +the brightness gradient +so that's available + + align:start position:0% +so that's available + + + align:start position:0% +so that's available +and then this we get from our + + align:start position:0% +and then this we get from our + + + align:start position:0% +and then this we get from our +reflectance model + + align:start position:0% +reflectance model + + + align:start position:0% +reflectance model +so + + align:start position:0% +so + + + align:start position:0% +so +this is from the reflectance map + + align:start position:0% + + + + align:start position:0% + +um you know assuming we know p and q and + + align:start position:0% +um you know assuming we know p and q and + + + align:start position:0% +um you know assuming we know p and q and +we said we're carrying along x y z p and + + align:start position:0% +we said we're carrying along x y z p and + + + align:start position:0% +we said we're carrying along x y z p and +q + + align:start position:0% +q + + + align:start position:0% +q +and so uh + + align:start position:0% +and so uh + + + align:start position:0% +and so uh +if we have a model of how the surface + + align:start position:0% +if we have a model of how the surface + + + align:start position:0% +if we have a model of how the surface +reflects light we can we have a + + align:start position:0% +reflects light we can we have a + + + align:start position:0% +reflects light we can we have a +reflectance map we can just take the + + align:start position:0% +reflectance map we can just take the + + + align:start position:0% +reflectance map we can just take the +gradient in the reflectance map which is + + align:start position:0% +gradient in the reflectance map which is + + + align:start position:0% +gradient in the reflectance map which is +r sub p r sub q so so we have this + + align:start position:0% +r sub p r sub q so so we have this + + + align:start position:0% +r sub p r sub q so so we have this +vector and we have that vector can we + + align:start position:0% +vector and we have that vector can we + + + align:start position:0% +vector and we have that vector can we +solve for h + + align:start position:0% + + + + align:start position:0% + +so you know one of the things we use a + + align:start position:0% +so you know one of the things we use a + + + align:start position:0% +so you know one of the things we use a +lot is + + align:start position:0% +lot is + + + align:start position:0% +lot is +uh equation counting and constraint + + align:start position:0% +uh equation counting and constraint + + + align:start position:0% +uh equation counting and constraint +counting + + align:start position:0% +counting + + + align:start position:0% +counting +unknown counting + + align:start position:0% +unknown counting + + + align:start position:0% +unknown counting +so what do we got + + align:start position:0% +so what do we got + + + align:start position:0% +so what do we got +well these are two equations two linear + + align:start position:0% +well these are two equations two linear + + + align:start position:0% +well these are two equations two linear +equations so two equations how many + + align:start position:0% +equations so two equations how many + + + align:start position:0% +equations so two equations how many +unknowns + + align:start position:0% + + + + align:start position:0% + +ah three right we got r s and t + + align:start position:0% +ah three right we got r s and t + + + align:start position:0% +ah three right we got r s and t +so uh + + align:start position:0% +so uh + + + align:start position:0% +so uh +no + + align:start position:0% +no + + + align:start position:0% +no +we can't do that + + align:start position:0% +we can't do that + + + align:start position:0% +we can't do that +that that's too bad we had a very good + + align:start position:0% +that that's too bad we had a very good + + + align:start position:0% +that that's too bad we had a very good +thing going there + + align:start position:0% +thing going there + + + align:start position:0% +thing going there +you know because here we we can get this + + align:start position:0% +you know because here we we can get this + + + align:start position:0% +you know because here we we can get this +from the image we can get that from the + + align:start position:0% +from the image we can get that from the + + + align:start position:0% +from the image we can get that from the +reflectance map and if we could solve + + align:start position:0% +reflectance map and if we could solve + + + align:start position:0% +reflectance map and if we could solve +for h we could plug it in here and we + + align:start position:0% +for h we could plug it in here and we + + + align:start position:0% +for h we could plug it in here and we +would uh we'd be we'd be done + + align:start position:0% +would uh we'd be we'd be done + + + align:start position:0% +would uh we'd be we'd be done +okay so here's the the whole trick of + + align:start position:0% +okay so here's the the whole trick of + + + align:start position:0% +okay so here's the the whole trick of +the method + + align:start position:0% +the method + + + align:start position:0% +the method +which is + + align:start position:0% + + + + align:start position:0% + +that + + align:start position:0% +that + + + align:start position:0% +that +because h appears in both of these + + align:start position:0% +because h appears in both of these + + + align:start position:0% +because h appears in both of these +equations + + align:start position:0% +equations + + + align:start position:0% +equations +we can make some progress + + align:start position:0% +we can make some progress + + + align:start position:0% +we can make some progress +we won't be able to solve for h + + align:start position:0% +we won't be able to solve for h + + + align:start position:0% +we won't be able to solve for h +but uh + + align:start position:0% +but uh + + + align:start position:0% +but uh +that's not really our aim our aim is to + + align:start position:0% +that's not really our aim our aim is to + + + align:start position:0% +that's not really our aim our aim is to +get an increment p and q + + align:start position:0% +get an increment p and q + + + align:start position:0% +get an increment p and q +right the only reason we want h is + + align:start position:0% +right the only reason we want h is + + + align:start position:0% +right the only reason we want h is +because this is our formula for + + align:start position:0% +because this is our formula for + + + align:start position:0% +because this is our formula for +computing the change in p and q um + + align:start position:0% +computing the change in p and q um + + + align:start position:0% +computing the change in p and q um +well + + align:start position:0% +well + + + align:start position:0% +well +maybe we can't solve for h + + align:start position:0% +maybe we can't solve for h + + + align:start position:0% +maybe we can't solve for h +uh but maybe if we pick delta x delta y + + align:start position:0% +uh but maybe if we pick delta x delta y + + + align:start position:0% +uh but maybe if we pick delta x delta y +in a nice way + + align:start position:0% +in a nice way + + + align:start position:0% +in a nice way +we can use this formula right and so + + align:start position:0% +we can use this formula right and so + + + align:start position:0% +we can use this formula right and so +how would we pick it well we'd want to + + align:start position:0% +how would we pick it well we'd want to + + + align:start position:0% +how would we pick it well we'd want to +match you know pat and match these two + + align:start position:0% +match you know pat and match these two + + + align:start position:0% +match you know pat and match these two +things right + + align:start position:0% +things right + + + align:start position:0% +things right +so can you can you see what what's going + + align:start position:0% +so can you can you see what what's going + + + align:start position:0% +so can you can you see what what's going +to happen + + align:start position:0% +to happen + + + align:start position:0% +to happen +what's the direction that we're going to + + align:start position:0% +what's the direction that we're going to + + + align:start position:0% +what's the direction that we're going to +go what what del what delta x and delta + + align:start position:0% +go what what del what delta x and delta + + + align:start position:0% +go what what del what delta x and delta +y would you use + + align:start position:0% +y would you use + + + align:start position:0% +y would you use +so that we can actually compute delta p + + align:start position:0% +so that we can actually compute delta p + + + align:start position:0% +so that we can actually compute delta p +delta q using that formula + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +pattern match + + align:start position:0% +pattern match + + + align:start position:0% +pattern match +okay how about this + + align:start position:0% +okay how about this + + + align:start position:0% +okay how about this +equals that + + align:start position:0% +equals that + + + align:start position:0% +equals that +right so let's try + + align:start position:0% +right so let's try + + + align:start position:0% +right so let's try +um + + align:start position:0% + + + + align:start position:0% + +and just so we can control the step size + + align:start position:0% +and just so we can control the step size + + + align:start position:0% +and just so we can control the step size +let's do + + align:start position:0% +let's do + + + align:start position:0% +let's do +multiply it by some small quantity + + align:start position:0% +multiply it by some small quantity + + + align:start position:0% +multiply it by some small quantity +so so that's it i mean before um + + align:start position:0% + + + + align:start position:0% + +we had a direction that we had to pick + + align:start position:0% +we had a direction that we had to pick + + + align:start position:0% +we had a direction that we had to pick +and remember we couldn't + + align:start position:0% +and remember we couldn't + + + align:start position:0% +and remember we couldn't +compute the profile in any other + + align:start position:0% +compute the profile in any other + + + align:start position:0% +compute the profile in any other +direction the direction was given but + + align:start position:0% +direction the direction was given but + + + align:start position:0% +direction the direction was given but +what was special about hakker was that + + align:start position:0% +what was special about hakker was that + + + align:start position:0% +what was special about hakker was that +that direction was the same everywhere + + align:start position:0% +that direction was the same everywhere + + + align:start position:0% +that direction was the same everywhere +so it was like built into the whole + + align:start position:0% +so it was like built into the whole + + + align:start position:0% +so it was like built into the whole +solution well now maybe the direction is + + align:start position:0% +solution well now maybe the direction is + + + align:start position:0% +solution well now maybe the direction is +going to change as we explore + + align:start position:0% +going to change as we explore + + + align:start position:0% +going to change as we explore +the surface + + align:start position:0% +the surface + + + align:start position:0% +the surface +okay so what happens if we try this well + + align:start position:0% +okay so what happens if we try this well + + + align:start position:0% +okay so what happens if we try this well +then we plug that into + + align:start position:0% +then we plug that into + + + align:start position:0% +then we plug that into +that equation and we get this and we get + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +again there's a particular direction + + align:start position:0% +again there's a particular direction + + + align:start position:0% +again there's a particular direction +that we can make progress in and that's + + align:start position:0% +that we can make progress in and that's + + + align:start position:0% +that we can make progress in and that's +this direction + + align:start position:0% +this direction + + + align:start position:0% +this direction +and if we go in that direction we can + + align:start position:0% +and if we go in that direction we can + + + align:start position:0% +and if we go in that direction we can +figure out what how to change p and q + + align:start position:0% +figure out what how to change p and q + + + align:start position:0% +figure out what how to change p and q +and and that's it + + align:start position:0% +and and that's it + + + align:start position:0% +and and that's it +we're done + + align:start position:0% +we're done + + + align:start position:0% +we're done +so if we want to summarize all of this + + align:start position:0% +so if we want to summarize all of this + + + align:start position:0% +so if we want to summarize all of this +we have + + align:start position:0% + + + + align:start position:0% + +right that's just uh + + align:start position:0% +right that's just uh + + + align:start position:0% +right that's just uh +from here + + align:start position:0% +from here + + + align:start position:0% +from here +and then we've got let's leave out dz + + align:start position:0% +and then we've got let's leave out dz + + + align:start position:0% +and then we've got let's leave out dz +for the moment dpd + + align:start position:0% + + + + align:start position:0% + +and of course we're interested in z so + + align:start position:0% +and of course we're interested in z so + + + align:start position:0% +and of course we're interested in z so +we need to write that one as well + + align:start position:0% + + + + align:start position:0% + +so what we've got is five uh ordinary + + align:start position:0% +so what we've got is five uh ordinary + + + align:start position:0% +so what we've got is five uh ordinary +differential equations and they're you + + align:start position:0% +differential equations and they're you + + + align:start position:0% +differential equations and they're you +know particularly simple the first order + + align:start position:0% +know particularly simple the first order + + + align:start position:0% +know particularly simple the first order +equations and + + align:start position:0% +equations and + + + align:start position:0% +equations and +and so + + align:start position:0% +and so + + + align:start position:0% +and so +we explore the surface along these + + align:start position:0% +we explore the surface along these + + + align:start position:0% +we explore the surface along these +curves and actually along these strips + + align:start position:0% +curves and actually along these strips + + + align:start position:0% +curves and actually along these strips +and those are the equations that + + align:start position:0% +and those are the equations that + + + align:start position:0% +and those are the equations that +generate + + align:start position:0% +generate + + + align:start position:0% +generate +that strip + + align:start position:0% +that strip + + + align:start position:0% +that strip +so it's very simple we as we go along we + + align:start position:0% +so it's very simple we as we go along we + + + align:start position:0% +so it's very simple we as we go along we +have the image brightness we look at the + + align:start position:0% +have the image brightness we look at the + + + align:start position:0% +have the image brightness we look at the +brightness gradient and that's going to + + align:start position:0% +brightness gradient and that's going to + + + align:start position:0% +brightness gradient and that's going to +tell us how to update p and q + + align:start position:0% +tell us how to update p and q + + + align:start position:0% +tell us how to update p and q +since we're carrying along p and q we + + align:start position:0% +since we're carrying along p and q we + + + align:start position:0% +since we're carrying along p and q we +know where we are in the reflectance map + + align:start position:0% +know where we are in the reflectance map + + + align:start position:0% +know where we are in the reflectance map +so we can compute + + align:start position:0% +so we can compute + + + align:start position:0% +so we can compute +r sub p r sub q that tells us + + align:start position:0% +r sub p r sub q that tells us + + + align:start position:0% +r sub p r sub q that tells us +the step to take the update in x and y + + align:start position:0% +the step to take the update in x and y + + + align:start position:0% +the step to take the update in x and y +and then + + align:start position:0% +and then + + + align:start position:0% +and then +well there's also the this + + align:start position:0% +well there's also the this + + + align:start position:0% +well there's also the this +output rule so to speak + + align:start position:0% + + + + align:start position:0% + +which tells us how much the height is + + align:start position:0% +which tells us how much the height is + + + align:start position:0% +which tells us how much the height is +changing and that's just you know + + align:start position:0% +changing and that's just you know + + + align:start position:0% +changing and that's just you know +based on p delta x plus q delta y + + align:start position:0% +based on p delta x plus q delta y + + + align:start position:0% +based on p delta x plus q delta y +same old formula we've used all along + + align:start position:0% +same old formula we've used all along + + + align:start position:0% +same old formula we've used all along +i i separate this equation from the rest + + align:start position:0% +i i separate this equation from the rest + + + align:start position:0% +i i separate this equation from the rest +because the others sort of have are a + + align:start position:0% +because the others sort of have are a + + + align:start position:0% +because the others sort of have are a +dynamic system that where the first two + + align:start position:0% +dynamic system that where the first two + + + align:start position:0% +dynamic system that where the first two +feed into the second two and the second + + align:start position:0% +feed into the second two and the second + + + align:start position:0% +feed into the second two and the second +two feed into the first two so you know + + align:start position:0% +two feed into the first two so you know + + + align:start position:0% +two feed into the first two so you know +if you're sort of thinking control + + align:start position:0% +if you're sort of thinking control + + + align:start position:0% +if you're sort of thinking control +theory and stability and stuff like that + + align:start position:0% +theory and stability and stuff like that + + + align:start position:0% +theory and stability and stuff like that +that's the interesting part that they're + + align:start position:0% +that's the interesting part that they're + + + align:start position:0% +that's the interesting part that they're +these two systems that are feeding uh + + align:start position:0% +these two systems that are feeding uh + + + align:start position:0% +these two systems that are feeding uh +into each other + + align:start position:0% +into each other + + + align:start position:0% +into each other +and it's + + align:start position:0% +and it's + + + align:start position:0% +and it's +it's kind of weird but what happens is + + align:start position:0% +it's kind of weird but what happens is + + + align:start position:0% +it's kind of weird but what happens is +that + + align:start position:0% + + + + align:start position:0% + +in the image space + + align:start position:0% +in the image space + + + align:start position:0% +in the image space +and the gradient space + + align:start position:0% + + + + align:start position:0% + +we have this + + align:start position:0% +we have this + + + align:start position:0% +we have this +way of going in uh gradient directions + + align:start position:0% +way of going in uh gradient directions + + + align:start position:0% +way of going in uh gradient directions +and so uh let's plot the isophotes in + + align:start position:0% +and so uh let's plot the isophotes in + + + align:start position:0% +and so uh let's plot the isophotes in +just some random isophotes in those two + + align:start position:0% +just some random isophotes in those two + + + align:start position:0% +just some random isophotes in those two +spaces + + align:start position:0% +spaces + + + align:start position:0% +spaces +so i don't know + + align:start position:0% +so i don't know + + + align:start position:0% +so i don't know +this one here could be + + align:start position:0% +this one here could be + + + align:start position:0% +this one here could be +sort of lamborghini and i don't know + + align:start position:0% +sort of lamborghini and i don't know + + + align:start position:0% +sort of lamborghini and i don't know +this is some + + align:start position:0% +this is some + + + align:start position:0% +this is some +whatever that is these are the isophotes + + align:start position:0% +whatever that is these are the isophotes + + + align:start position:0% +whatever that is these are the isophotes +in the image + + align:start position:0% +in the image + + + align:start position:0% +in the image +and what this is saying if we're at a + + align:start position:0% +and what this is saying if we're at a + + + align:start position:0% +and what this is saying if we're at a +particular point suppose we're here + + align:start position:0% +particular point suppose we're here + + + align:start position:0% +particular point suppose we're here +in x and y and we're also carrying along + + align:start position:0% +in x and y and we're also carrying along + + + align:start position:0% +in x and y and we're also carrying along +p and q so we also somewhere + + align:start position:0% +p and q so we also somewhere + + + align:start position:0% +p and q so we also somewhere +in + + align:start position:0% +in + + + align:start position:0% +in +let's suppose we're here + + align:start position:0% +let's suppose we're here + + + align:start position:0% +let's suppose we're here +then the step we take is based on the + + align:start position:0% +then the step we take is based on the + + + align:start position:0% +then the step we take is based on the +gradient which is perpendicular to the + + align:start position:0% +gradient which is perpendicular to the + + + align:start position:0% +gradient which is perpendicular to the +iso + + align:start position:0% +iso + + + align:start position:0% +iso +lines + + align:start position:0% +lines + + + align:start position:0% +lines +and so the step we take here though + + align:start position:0% +and so the step we take here though + + + align:start position:0% +and so the step we take here though +weirdly is dependent on the gradient + + align:start position:0% +weirdly is dependent on the gradient + + + align:start position:0% +weirdly is dependent on the gradient +there so + + align:start position:0% + + + + align:start position:0% + +so this is the actual step we take + + align:start position:0% +so this is the actual step we take + + + align:start position:0% +so this is the actual step we take +and then the step we take in p and q + + align:start position:0% +and then the step we take in p and q + + + align:start position:0% +and then the step we take in p and q +is strangely dependent on the + + align:start position:0% +is strangely dependent on the + + + align:start position:0% +is strangely dependent on the +gradient there + + align:start position:0% +gradient there + + + align:start position:0% +gradient there +so we actually take a step in that + + align:start position:0% +so we actually take a step in that + + + align:start position:0% +so we actually take a step in that +direction + + align:start position:0% + + + + align:start position:0% + +so it's you know a little weird you're + + align:start position:0% +so it's you know a little weird you're + + + align:start position:0% +so it's you know a little weird you're +not going uphill you're not just doing + + align:start position:0% +not going uphill you're not just doing + + + align:start position:0% +not going uphill you're not just doing +gradient ascent or gradient descent + + align:start position:0% +gradient ascent or gradient descent + + + align:start position:0% +gradient ascent or gradient descent +but you're going in the gradient in in + + align:start position:0% +but you're going in the gradient in in + + + align:start position:0% +but you're going in the gradient in in +the other diagram anyway uh + + align:start position:0% +the other diagram anyway uh + + + align:start position:0% +the other diagram anyway uh +this makes it clear you know how to + + align:start position:0% +this makes it clear you know how to + + + align:start position:0% +this makes it clear you know how to +implement that you just have to have + + align:start position:0% +implement that you just have to have + + + align:start position:0% +implement that you just have to have +these two things + + align:start position:0% +these two things + + + align:start position:0% +these two things +the + + align:start position:0% +the + + + align:start position:0% +the +image + + align:start position:0% +image + + + align:start position:0% +image +e of x and y + + align:start position:0% +e of x and y + + + align:start position:0% +e of x and y +and the reflectance map r of p and q + + align:start position:0% +and the reflectance map r of p and q + + + align:start position:0% +and the reflectance map r of p and q +and once you're plonked down somewhere + + align:start position:0% +and once you're plonked down somewhere + + + align:start position:0% +and once you're plonked down somewhere +in there you just follow this rule + + align:start position:0% +in there you just follow this rule + + + align:start position:0% +in there you just follow this rule +and it'll trace out + + align:start position:0% +and it'll trace out + + + align:start position:0% +and it'll trace out +a curve in the image and indirectly + + align:start position:0% +a curve in the image and indirectly + + + align:start position:0% +a curve in the image and indirectly +it'll trace out a curve in 3d + + align:start position:0% +it'll trace out a curve in 3d + + + align:start position:0% +it'll trace out a curve in 3d +and actually it'll trace out a whole + + align:start position:0% +and actually it'll trace out a whole + + + align:start position:0% +and actually it'll trace out a whole +strip because all along we know the + + align:start position:0% +strip because all along we know the + + + align:start position:0% +strip because all along we know the +surface orientation + + align:start position:0% +surface orientation + + + align:start position:0% +surface orientation +and that's a little different from the + + align:start position:0% +and that's a little different from the + + + align:start position:0% +and that's a little different from the +hapka case + + align:start position:0% +hapka case + + + align:start position:0% +hapka case +where we don't know p and q as we go + + align:start position:0% +where we don't know p and q as we go + + + align:start position:0% +where we don't know p and q as we go +along we only know one component in a + + align:start position:0% +along we only know one component in a + + + align:start position:0% +along we only know one component in a +certain direction + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +we've reduced + + align:start position:0% +we've reduced + + + align:start position:0% +we've reduced +our image irradiance equation + + align:start position:0% + + + + align:start position:0% + +to those + + align:start position:0% +to those + + + align:start position:0% +to those +simple + + align:start position:0% +simple + + + align:start position:0% +simple +ordinary differential coupled ordinary + + align:start position:0% +ordinary differential coupled ordinary + + + align:start position:0% +ordinary differential coupled ordinary +differential equations and this is a + + align:start position:0% +differential equations and this is a + + + align:start position:0% +differential equations and this is a +partial differential equation + + align:start position:0% +partial differential equation + + + align:start position:0% +partial differential equation +why is that well because p is dz dx + + align:start position:0% +why is that well because p is dz dx + + + align:start position:0% +why is that well because p is dz dx +and q is dzby + + align:start position:0% +and q is dzby + + + align:start position:0% +and q is dzby +and we're just sort of making things + + align:start position:0% +and we're just sort of making things + + + align:start position:0% +and we're just sort of making things +look less intimidating by using these + + align:start position:0% +look less intimidating by using these + + + align:start position:0% +look less intimidating by using these +abbreviations p and q but this is really + + align:start position:0% +abbreviations p and q but this is really + + + align:start position:0% +abbreviations p and q but this is really +a first order non-linear partial + + align:start position:0% +a first order non-linear partial + + + align:start position:0% +a first order non-linear partial +differential equation and you know + + align:start position:0% +differential equation and you know + + + align:start position:0% +differential equation and you know +in physics you run into loads of partial + + align:start position:0% +in physics you run into loads of partial + + + align:start position:0% +in physics you run into loads of partial +differential equations + + align:start position:0% +differential equations + + + align:start position:0% +differential equations +but they're + + align:start position:0% +but they're + + + align:start position:0% +but they're +generally + + align:start position:0% +generally + + + align:start position:0% +generally +um + + align:start position:0% +um + + + align:start position:0% +um +second order those are the ones of + + align:start position:0% +second order those are the ones of + + + align:start position:0% +second order those are the ones of +interest you know heat flow + + align:start position:0% +interest you know heat flow + + + align:start position:0% +interest you know heat flow +wave propagation + + align:start position:0% +wave propagation + + + align:start position:0% +wave propagation +so they're typically second order and + + align:start position:0% +so they're typically second order and + + + align:start position:0% +so they're typically second order and +they're typically linear + + align:start position:0% +they're typically linear + + + align:start position:0% +they're typically linear +and here we've got something unusual we + + align:start position:0% +and here we've got something unusual we + + + align:start position:0% +and here we've got something unusual we +have first order which you think should + + align:start position:0% +have first order which you think should + + + align:start position:0% +have first order which you think should +be simpler + + align:start position:0% +be simpler + + + align:start position:0% +be simpler +and it's non-linear + + align:start position:0% +and it's non-linear + + + align:start position:0% +and it's non-linear +and so + + align:start position:0% + + + + align:start position:0% + +so you know + + align:start position:0% +so you know + + + align:start position:0% +so you know +if it wasn't for that i wouldn't have to + + align:start position:0% +if it wasn't for that i wouldn't have to + + + align:start position:0% +if it wasn't for that i wouldn't have to +explain all of this because you would + + align:start position:0% +explain all of this because you would + + + align:start position:0% +explain all of this because you would +have learned this in physics but physics + + align:start position:0% +have learned this in physics but physics + + + align:start position:0% +have learned this in physics but physics +does second order linear pdes and not + + align:start position:0% +does second order linear pdes and not + + + align:start position:0% +does second order linear pdes and not +first order non-linear pdes so + + align:start position:0% +first order non-linear pdes so + + + align:start position:0% +first order non-linear pdes so +we've just + + align:start position:0% +we've just + + + align:start position:0% +we've just +come up with a method for solving those + + align:start position:0% +come up with a method for solving those + + + align:start position:0% +come up with a method for solving those +and that that's what we need to do in + + align:start position:0% +and that that's what we need to do in + + + align:start position:0% +and that that's what we need to do in +shape from shading since the brightness + + align:start position:0% +shape from shading since the brightness + + + align:start position:0% +shape from shading since the brightness +depends on the first derivative so + + align:start position:0% +depends on the first derivative so + + + align:start position:0% +depends on the first derivative so +okay + + align:start position:0% +okay + + + align:start position:0% +okay +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +now this is general for any r of p and q + + align:start position:0% +now this is general for any r of p and q + + + align:start position:0% +now this is general for any r of p and q +let's just take a look at it for some + + align:start position:0% +let's just take a look at it for some + + + align:start position:0% +let's just take a look at it for some +particular + + align:start position:0% + + + + align:start position:0% + +surface properties that we've been + + align:start position:0% +surface properties that we've been + + + align:start position:0% +surface properties that we've been +studying so one of them of course is + + align:start position:0% +studying so one of them of course is + + + align:start position:0% +studying so one of them of course is +hapki and that's a special case we + + align:start position:0% +hapki and that's a special case we + + + align:start position:0% +hapki and that's a special case we +solved up there but let's just see how + + align:start position:0% +solved up there but let's just see how + + + align:start position:0% +solved up there but let's just see how +the general case reduces + + align:start position:0% +the general case reduces + + + align:start position:0% +the general case reduces +if + + align:start position:0% +if + + + align:start position:0% +if +we you assume this for the reflectance + + align:start position:0% +we you assume this for the reflectance + + + align:start position:0% +we you assume this for the reflectance +map + + align:start position:0% +map + + + align:start position:0% +map +okay so here + + align:start position:0% + + + + align:start position:0% + +so that's a reflectance map for for + + align:start position:0% +so that's a reflectance map for for + + + align:start position:0% +so that's a reflectance map for for +hopkins so what do we need we need r r + + align:start position:0% +hopkins so what do we need we need r r + + + align:start position:0% +hopkins so what do we need we need r r +sub p + + align:start position:0% +sub p + + + align:start position:0% +sub p +so we differentiate this with respect to + + align:start position:0% +so we differentiate this with respect to + + + align:start position:0% +so we differentiate this with respect to +p + + align:start position:0% +p + + + align:start position:0% +p +as square root so we're going to get a + + align:start position:0% +as square root so we're going to get a + + + align:start position:0% +as square root so we're going to get a +half + + align:start position:0% +half + + + align:start position:0% +half +divided by the square root let's take + + align:start position:0% +divided by the square root let's take + + + align:start position:0% +divided by the square root let's take +out the 1 over square root of r s first + + align:start position:0% +out the 1 over square root of r s first + + + align:start position:0% +out the 1 over square root of r s first +it's just a constant + + align:start position:0% +it's just a constant + + + align:start position:0% +it's just a constant +and then the rest is going to be 1 over + + align:start position:0% + + + + align:start position:0% + +right because um we have something + + align:start position:0% +right because um we have something + + + align:start position:0% +right because um we have something +raised to the half power so you + + align:start position:0% +raised to the half power so you + + + align:start position:0% +raised to the half power so you +differentiate that you get a half times + + align:start position:0% +differentiate that you get a half times + + + align:start position:0% +differentiate that you get a half times +that thing to the minus half power + + align:start position:0% +that thing to the minus half power + + + align:start position:0% +that thing to the minus half power +and then we have to differentiate what's + + align:start position:0% +and then we have to differentiate what's + + + align:start position:0% +and then we have to differentiate what's +this term inside with respect to p and + + align:start position:0% +this term inside with respect to p and + + + align:start position:0% +this term inside with respect to p and +we get ps + + align:start position:0% + + + + align:start position:0% + +and of course r sub q is very similar + + align:start position:0% + + + + align:start position:0% + +and then the other one we need is p r + + align:start position:0% +and then the other one we need is p r + + + align:start position:0% +and then the other one we need is p r +sub p plus q r sub q + + align:start position:0% +sub p plus q r sub q + + + align:start position:0% +sub p plus q r sub q +and that's just going to be the same + + align:start position:0% +and that's just going to be the same + + + align:start position:0% +and that's just going to be the same +thing + + align:start position:0% + + + + align:start position:0% + +now + + align:start position:0% + + + + align:start position:0% + +these three share this + + align:start position:0% + + + + align:start position:0% + +multiplier + + align:start position:0% +multiplier + + + align:start position:0% +multiplier +and that multiplier as you mentioned + + align:start position:0% +and that multiplier as you mentioned + + + align:start position:0% +and that multiplier as you mentioned +last time it's it's really just + + align:start position:0% +last time it's it's really just + + + align:start position:0% +last time it's it's really just +controlling how fast + + align:start position:0% +controlling how fast + + + align:start position:0% +controlling how fast +you go along the curve as you solve it + + align:start position:0% +you go along the curve as you solve it + + + align:start position:0% +you go along the curve as you solve it +so you could + + align:start position:0% +so you could + + + align:start position:0% +so you could +change that and + + align:start position:0% +change that and + + + align:start position:0% +change that and +i mean it would change numerical + + align:start position:0% +i mean it would change numerical + + + align:start position:0% +i mean it would change numerical +stability and you know how accurate the + + align:start position:0% +stability and you know how accurate the + + + align:start position:0% +stability and you know how accurate the +solution is but in the infinitesimal + + align:start position:0% +solution is but in the infinitesimal + + + align:start position:0% +solution is but in the infinitesimal +case it wouldn't change the solution so + + align:start position:0% +case it wouldn't change the solution so + + + align:start position:0% +case it wouldn't change the solution so +actually + + align:start position:0% +actually + + + align:start position:0% +actually +we could + + align:start position:0% +we could + + + align:start position:0% +we could +remove these three terms + + align:start position:0% +remove these three terms + + + align:start position:0% +remove these three terms +as long as we do it on all three + + align:start position:0% +as long as we do it on all three + + + align:start position:0% +as long as we do it on all three +equations and then we have rp is + + align:start position:0% +equations and then we have rp is + + + align:start position:0% +equations and then we have rp is +proportional to ps and rq is + + align:start position:0% +proportional to ps and rq is + + + align:start position:0% +proportional to ps and rq is +proportional to qs and so our update + + align:start position:0% +proportional to qs and so our update + + + align:start position:0% +proportional to qs and so our update +rules + + align:start position:0% + + + + align:start position:0% + +you know the update rule for x is just p + + align:start position:0% +you know the update rule for x is just p + + + align:start position:0% +you know the update rule for x is just p +s the update rule for y is q s and and + + align:start position:0% +s the update rule for y is q s and and + + + align:start position:0% +s the update rule for y is q s and and +that's what we had had up there so + + align:start position:0% +that's what we had had up there so + + + align:start position:0% +that's what we had had up there so +so the general case + + align:start position:0% +so the general case + + + align:start position:0% +so the general case +reduces down to + + align:start position:0% +reduces down to + + + align:start position:0% +reduces down to +this pretty easily particularly since i + + align:start position:0% +this pretty easily particularly since i + + + align:start position:0% +this pretty easily particularly since i +guess this is let's see r s e squared + + align:start position:0% +guess this is let's see r s e squared + + + align:start position:0% +guess this is let's see r s e squared +minus one + + align:start position:0% +minus one + + + align:start position:0% +minus one +as we showed + + align:start position:0% +as we showed + + + align:start position:0% +as we showed +up there somewhere + + align:start position:0% +up there somewhere + + + align:start position:0% +up there somewhere +okay so + + align:start position:0% +okay so + + + align:start position:0% +okay so +that's good the general case reduces + + align:start position:0% +that's good the general case reduces + + + align:start position:0% +that's good the general case reduces +correctly + + align:start position:0% +correctly + + + align:start position:0% +correctly +to that special case that + + align:start position:0% +to that special case that + + + align:start position:0% +to that special case that +we saw first + + align:start position:0% +we saw first + + + align:start position:0% +we saw first +um let's look at some + + align:start position:0% + + + + align:start position:0% + +other case + + align:start position:0% +other case + + + align:start position:0% +other case +so we said that in the scanning electron + + align:start position:0% +so we said that in the scanning electron + + + align:start position:0% +so we said that in the scanning electron +microscope + + align:start position:0% +microscope + + + align:start position:0% +microscope +we had dependence of + + align:start position:0% + + + + align:start position:0% + +slope uh right remember that + + align:start position:0% +slope uh right remember that + + + align:start position:0% +slope uh right remember that +you know unless you do something strange + + align:start position:0% +you know unless you do something strange + + + align:start position:0% +you know unless you do something strange +to your microscope it's rotationally + + align:start position:0% +to your microscope it's rotationally + + + align:start position:0% +to your microscope it's rotationally +symmetric + + align:start position:0% +symmetric + + + align:start position:0% +symmetric +in imaging and so if you look at a + + align:start position:0% +in imaging and so if you look at a + + + align:start position:0% +in imaging and so if you look at a +reflectance map for that instrument + + align:start position:0% +reflectance map for that instrument + + + align:start position:0% +reflectance map for that instrument +the brightness is only dependent on the + + align:start position:0% +the brightness is only dependent on the + + + align:start position:0% +the brightness is only dependent on the +slope + + align:start position:0% +slope + + + align:start position:0% +slope +not the you know the magnitude of the + + align:start position:0% +not the you know the magnitude of the + + + align:start position:0% +not the you know the magnitude of the +gradient not the gradient direction so + + align:start position:0% +gradient not the gradient direction so + + + align:start position:0% +gradient not the gradient direction so +okay so uh you know what's f well that + + align:start position:0% +okay so uh you know what's f well that + + + align:start position:0% +okay so uh you know what's f well that +depends on the instrument uh and it and + + align:start position:0% +depends on the instrument uh and it and + + + align:start position:0% +depends on the instrument uh and it and +also the material of the object and so + + align:start position:0% +also the material of the object and so + + + align:start position:0% +also the material of the object and so +you need to calibrate that but let's + + align:start position:0% +you need to calibrate that but let's + + + align:start position:0% +you need to calibrate that but let's +leave it general let's just leave it as + + align:start position:0% +leave it general let's just leave it as + + + align:start position:0% +leave it general let's just leave it as +as f + + align:start position:0% +as f + + + align:start position:0% +as f +okay then to use this method we need r + + align:start position:0% +okay then to use this method we need r + + + align:start position:0% +okay then to use this method we need r +sub p r sub q + + align:start position:0% + + + + align:start position:0% + +and we differentiate with respect to p + + align:start position:0% +and we differentiate with respect to p + + + align:start position:0% +and we differentiate with respect to p +and we get that + + align:start position:0% + + + + align:start position:0% + +and we differentiate with respect to q + + align:start position:0% +and we differentiate with respect to q + + + align:start position:0% +and we differentiate with respect to q +we get that and so this is going to tell + + align:start position:0% +we get that and so this is going to tell + + + align:start position:0% +we get that and so this is going to tell +us our update for + + align:start position:0% +us our update for + + + align:start position:0% +us our update for +x and this is going to tell us our + + align:start position:0% +x and this is going to tell us our + + + align:start position:0% +x and this is going to tell us our +update for y + + align:start position:0% +update for y + + + align:start position:0% +update for y +and we also need prp plus qrq + + align:start position:0% +and we also need prp plus qrq + + + align:start position:0% +and we also need prp plus qrq +which is going to be this constant times + + align:start position:0% + + + + align:start position:0% + +and this is our update for + + align:start position:0% +and this is our update for + + + align:start position:0% +and this is our update for +the height + + align:start position:0% + + + + align:start position:0% + +so we can certainly apply this method to + + align:start position:0% +so we can certainly apply this method to + + + align:start position:0% +so we can certainly apply this method to +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +scanning electron microscope images + + align:start position:0% +scanning electron microscope images + + + align:start position:0% +scanning electron microscope images +and again there's this constant + + align:start position:0% +and again there's this constant + + + align:start position:0% +and again there's this constant +multiplier here we'll talk about this + + align:start position:0% +multiplier here we'll talk about this + + + align:start position:0% +multiplier here we'll talk about this +some more + + align:start position:0% +some more + + + align:start position:0% +some more +but + + align:start position:0% +but + + + align:start position:0% +but +oh not the whole thing but that only + + align:start position:0% +oh not the whole thing but that only + + + align:start position:0% +oh not the whole thing but that only +affects how fast we move along the + + align:start position:0% +affects how fast we move along the + + + align:start position:0% +affects how fast we move along the +solution + + align:start position:0% +solution + + + align:start position:0% +solution +so we could actually simplify things + + align:start position:0% +so we could actually simplify things + + + align:start position:0% +so we could actually simplify things +by you know + + align:start position:0% +by you know + + + align:start position:0% +by you know +getting rid of that + + align:start position:0% +getting rid of that + + + align:start position:0% +getting rid of that +and then the equations are very simple + + align:start position:0% +and then the equations are very simple + + + align:start position:0% +and then the equations are very simple +what is it telling us it's telling us + + align:start position:0% +what is it telling us it's telling us + + + align:start position:0% +what is it telling us it's telling us +that the direction we're going is the + + align:start position:0% +that the direction we're going is the + + + align:start position:0% +that the direction we're going is the +gradient + + align:start position:0% +gradient + + + align:start position:0% +gradient +we're going + + align:start position:0% +we're going + + + align:start position:0% +we're going +uphill + + align:start position:0% +uphill + + + align:start position:0% +uphill +so the gradient + + align:start position:0% +so the gradient + + + align:start position:0% +so the gradient +is the direction of steepest descent + + align:start position:0% +is the direction of steepest descent + + + align:start position:0% +is the direction of steepest descent +so if i'm standing on the mountain + + align:start position:0% +so if i'm standing on the mountain + + + align:start position:0% +so if i'm standing on the mountain +you know you know what the gradient is + + align:start position:0% +you know you know what the gradient is + + + align:start position:0% +you know you know what the gradient is +so + + align:start position:0% +so + + + align:start position:0% +so +that's where we're going or or downhill + + align:start position:0% +that's where we're going or or downhill + + + align:start position:0% +that's where we're going or or downhill +we can as we said we can reverse the + + align:start position:0% +we can as we said we can reverse the + + + align:start position:0% +we can as we said we can reverse the +direction we can make uh delta uh chi + + align:start position:0% +direction we can make uh delta uh chi + + + align:start position:0% +direction we can make uh delta uh chi +chi be negative and go in minus p minus + + align:start position:0% +chi be negative and go in minus p minus + + + align:start position:0% +chi be negative and go in minus p minus +q direction so it's very simple and then + + align:start position:0% +q direction so it's very simple and then + + + align:start position:0% +q direction so it's very simple and then +here's the + + align:start position:0% +here's the + + + align:start position:0% +here's the +rule that tells us how much we're + + align:start position:0% +rule that tells us how much we're + + + align:start position:0% +rule that tells us how much we're +updating z so + + align:start position:0% +updating z so + + + align:start position:0% +updating z so +so scanning electron microscope is a + + align:start position:0% +so scanning electron microscope is a + + + align:start position:0% +so scanning electron microscope is a +little bit simpler than you know + + align:start position:0% +little bit simpler than you know + + + align:start position:0% +little bit simpler than you know +lambertian + + align:start position:0% +lambertian + + + align:start position:0% +lambertian +but it + + align:start position:0% +but it + + + align:start position:0% +but it +you know + + align:start position:0% +you know + + + align:start position:0% +you know +rather than solve this one + + align:start position:0% +rather than solve this one + + + align:start position:0% +rather than solve this one +separately + + align:start position:0% +separately + + + align:start position:0% +separately +after doing hapka we just went to the + + align:start position:0% +after doing hapka we just went to the + + + align:start position:0% +after doing hapka we just went to the +general case in general + + align:start position:0% +general case in general + + + align:start position:0% +general case in general +okay and you can do the same for + + align:start position:0% +okay and you can do the same for + + + align:start position:0% +okay and you can do the same for +lambertian unfortunately it gets messy + + align:start position:0% +lambertian unfortunately it gets messy + + + align:start position:0% +lambertian unfortunately it gets messy +because the lambertian has that square + + align:start position:0% +because the lambertian has that square + + + align:start position:0% +because the lambertian has that square +root and the 1 plus p squared plus q + + align:start position:0% +root and the 1 plus p squared plus q + + + align:start position:0% +root and the 1 plus p squared plus q +squared + + align:start position:0% +squared + + + align:start position:0% +squared +but of course you can you can't do it + + align:start position:0% + + + + align:start position:0% + +okay so a couple of things the one to + + align:start position:0% +okay so a couple of things the one to + + + align:start position:0% +okay so a couple of things the one to +remember is that we're dealing with a + + align:start position:0% +remember is that we're dealing with a + + + align:start position:0% +remember is that we're dealing with a +solution that generates + + align:start position:0% +solution that generates + + + align:start position:0% +solution that generates +characteristic strips + + align:start position:0% +characteristic strips + + + align:start position:0% +characteristic strips +so we're not just exploring the surface + + align:start position:0% +so we're not just exploring the surface + + + align:start position:0% +so we're not just exploring the surface +along curves + + align:start position:0% +along curves + + + align:start position:0% +along curves +but along the curve we also know the + + align:start position:0% +but along the curve we also know the + + + align:start position:0% +but along the curve we also know the +surface orientation + + align:start position:0% +surface orientation + + + align:start position:0% +surface orientation +and then um + + align:start position:0% +and then um + + + align:start position:0% +and then um +another related concept is that of a + + align:start position:0% +another related concept is that of a + + + align:start position:0% +another related concept is that of a +base characteristic + + align:start position:0% + + + + align:start position:0% + +okay so the characteristic strip has x y + + align:start position:0% +okay so the characteristic strip has x y + + + align:start position:0% +okay so the characteristic strip has x y +z uh p and q along the strip + + align:start position:0% +z uh p and q along the strip + + + align:start position:0% +z uh p and q along the strip +and the base characteristic is just + + align:start position:0% + + + + align:start position:0% + +let's see + + align:start position:0% + + + + align:start position:0% + +the projection into the image plane + + align:start position:0% +the projection into the image plane + + + align:start position:0% +the projection into the image plane +and to some extent that's of interest to + + align:start position:0% +and to some extent that's of interest to + + + align:start position:0% +and to some extent that's of interest to +us because + + align:start position:0% +us because + + + align:start position:0% +us because +uh you know that's what we have we have + + align:start position:0% +uh you know that's what we have we have + + + align:start position:0% +uh you know that's what we have we have +the image we're trying to explore it and + + align:start position:0% +the image we're trying to explore it and + + + align:start position:0% +the image we're trying to explore it and +uh for one thing we want to make sure + + align:start position:0% +uh for one thing we want to make sure + + + align:start position:0% +uh for one thing we want to make sure +that we sort of cover much of the image + + align:start position:0% +that we sort of cover much of the image + + + align:start position:0% +that we sort of cover much of the image +with these curves + + align:start position:0% +with these curves + + + align:start position:0% +with these curves +uh and of course the ultimate goal is + + align:start position:0% +uh and of course the ultimate goal is + + + align:start position:0% +uh and of course the ultimate goal is +the surface in 3d + + align:start position:0% +the surface in 3d + + + align:start position:0% +the surface in 3d +but we're also quite interested in in + + align:start position:0% +but we're also quite interested in in + + + align:start position:0% +but we're also quite interested in in +what happens in the image plane that + + align:start position:0% +what happens in the image plane that + + + align:start position:0% +what happens in the image plane that +we're actually covering uh covering that + + align:start position:0% + + + + align:start position:0% + +okay so + + align:start position:0% +okay so + + + align:start position:0% +okay so +how what might this look like these bass + + align:start position:0% +how what might this look like these bass + + + align:start position:0% +how what might this look like these bass +characteristic + + align:start position:0% +characteristic + + + align:start position:0% +characteristic +so here's our image and uh + + align:start position:0% +so here's our image and uh + + + align:start position:0% +so here's our image and uh +for the moment we're assuming we have + + align:start position:0% +for the moment we're assuming we have + + + align:start position:0% +for the moment we're assuming we have +some sort of initial curve and then + + align:start position:0% +some sort of initial curve and then + + + align:start position:0% +some sort of initial curve and then +these uh + + align:start position:0% +these uh + + + align:start position:0% +these uh +base characteristics you know go + + align:start position:0% +base characteristics you know go + + + align:start position:0% +base characteristics you know go +out from there + + align:start position:0% + + + + align:start position:0% + +and and maybe the other direction + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +as i mentioned one reason you might be + + align:start position:0% +as i mentioned one reason you might be + + + align:start position:0% +as i mentioned one reason you might be +interested in these base characteristics + + align:start position:0% +interested in these base characteristics + + + align:start position:0% +interested in these base characteristics +is because + + align:start position:0% +is because + + + align:start position:0% +is because +you want to make sure that you're + + align:start position:0% +you want to make sure that you're + + + align:start position:0% +you want to make sure that you're +exploring as much as possible of the + + align:start position:0% +exploring as much as possible of the + + + align:start position:0% +exploring as much as possible of the +image + + align:start position:0% +image + + + align:start position:0% +image +and not leaving out some areas and also + + align:start position:0% +and not leaving out some areas and also + + + align:start position:0% +and not leaving out some areas and also +you might say well + + align:start position:0% +you might say well + + + align:start position:0% +you might say well +you know this is sort of no man's land + + align:start position:0% +you know this is sort of no man's land + + + align:start position:0% +you know this is sort of no man's land +i should really be interpolating another + + align:start position:0% +i should really be interpolating another + + + align:start position:0% +i should really be interpolating another +one in here + + align:start position:0% +one in here + + + align:start position:0% +one in here +and in some other areas + + align:start position:0% +and in some other areas + + + align:start position:0% +and in some other areas +conversely + + align:start position:0% +conversely + + + align:start position:0% +conversely +the base characteristics might get close + + align:start position:0% +the base characteristics might get close + + + align:start position:0% +the base characteristics might get close +together + + align:start position:0% +together + + + align:start position:0% +together +and you might say well that's + + align:start position:0% +and you might say well that's + + + align:start position:0% +and you might say well that's +unreasonable + + align:start position:0% +unreasonable + + + align:start position:0% +unreasonable +i should really have the same pretty + + align:start position:0% +i should really have the same pretty + + + align:start position:0% +i should really have the same pretty +much the same height there so just drop + + align:start position:0% +much the same height there so just drop + + + align:start position:0% +much the same height there so just drop +one of them or merge them take their + + align:start position:0% +one of them or merge them take their + + + align:start position:0% +one of them or merge them take their +average + + align:start position:0% + + + + align:start position:0% + +so in terms of + + align:start position:0% +so in terms of + + + align:start position:0% +so in terms of +you know implementing this + + align:start position:0% +you know implementing this + + + align:start position:0% +you know implementing this +you'd be looking at these base + + align:start position:0% +you'd be looking at these base + + + align:start position:0% +you'd be looking at these base +characteristics + + align:start position:0% +characteristics + + + align:start position:0% +characteristics +and + + align:start position:0% +and + + + align:start position:0% +and +interpolating and removing as required + + align:start position:0% +interpolating and removing as required + + + align:start position:0% +interpolating and removing as required +so + + align:start position:0% + + + + align:start position:0% + +now another issue is + + align:start position:0% +now another issue is + + + align:start position:0% +now another issue is +you know it sounds very sequential which + + align:start position:0% +you know it sounds very sequential which + + + align:start position:0% +you know it sounds very sequential which +is + + align:start position:0% +is + + + align:start position:0% +is +unpleasant from the point of view of + + align:start position:0% +unpleasant from the point of view of + + + align:start position:0% +unpleasant from the point of view of +implementation + + align:start position:0% +implementation + + + align:start position:0% +implementation +because it could take a long time to do + + align:start position:0% +because it could take a long time to do + + + align:start position:0% +because it could take a long time to do +this + + align:start position:0% +this + + + align:start position:0% +this +and also + + align:start position:0% +and also + + + align:start position:0% +and also +unpleasant from the point of view of + + align:start position:0% +unpleasant from the point of view of + + + align:start position:0% +unpleasant from the point of view of +biological interpretation + + align:start position:0% +biological interpretation + + + align:start position:0% +biological interpretation +but it turns out that the solutions + + align:start position:0% +but it turns out that the solutions + + + align:start position:0% +but it turns out that the solutions +along these curves are independent i + + align:start position:0% +along these curves are independent i + + + align:start position:0% +along these curves are independent i +mean each of them satisfies + + align:start position:0% +mean each of them satisfies + + + align:start position:0% +mean each of them satisfies +a set of differential equations and the + + align:start position:0% +a set of differential equations and the + + + align:start position:0% +a set of differential equations and the +only way they interact is that well they + + align:start position:0% +only way they interact is that well they + + + align:start position:0% +only way they interact is that well they +all sprout from the initial curve + + align:start position:0% +all sprout from the initial curve + + + align:start position:0% +all sprout from the initial curve +so + + align:start position:0% +so + + + align:start position:0% +so +actually you could have a process + + align:start position:0% +actually you could have a process + + + align:start position:0% +actually you could have a process +running along each of these curves so it + + align:start position:0% +running along each of these curves so it + + + align:start position:0% +running along each of these curves so it +is parallelizable + + align:start position:0% +is parallelizable + + + align:start position:0% +is parallelizable +and + + align:start position:0% +and + + + align:start position:0% +and +that's actually kind of uh implied by + + align:start position:0% +that's actually kind of uh implied by + + + align:start position:0% +that's actually kind of uh implied by +what i said a minute ago because + + align:start position:0% +what i said a minute ago because + + + align:start position:0% +what i said a minute ago because +if you're going to interpolate new + + align:start position:0% +if you're going to interpolate new + + + align:start position:0% +if you're going to interpolate new +characteristics it's best that you do it + + align:start position:0% +characteristics it's best that you do it + + + align:start position:0% +characteristics it's best that you do it +as as you + + align:start position:0% +as as you + + + align:start position:0% +as as you +grow + + align:start position:0% +grow + + + align:start position:0% +grow +and say oh wait these two are getting + + align:start position:0% +and say oh wait these two are getting + + + align:start position:0% +and say oh wait these two are getting +too far apart so let me interpolate a + + align:start position:0% +too far apart so let me interpolate a + + + align:start position:0% +too far apart so let me interpolate a +new one there or if they get too close + + align:start position:0% +new one there or if they get too close + + + align:start position:0% +new one there or if they get too close +together let me merge them so + + align:start position:0% +together let me merge them so + + + align:start position:0% +together let me merge them so +so um + + align:start position:0% +so um + + + align:start position:0% +so um +it's not full parallelism it's not like + + align:start position:0% +it's not full parallelism it's not like + + + align:start position:0% +it's not full parallelism it's not like +you can + + align:start position:0% +you can + + + align:start position:0% +you can +do something at every pixel at the same + + align:start position:0% +do something at every pixel at the same + + + align:start position:0% +do something at every pixel at the same +time + + align:start position:0% +time + + + align:start position:0% +time +but it's a + + align:start position:0% +but it's a + + + align:start position:0% +but it's a +significant uh + + align:start position:0% +significant uh + + + align:start position:0% +significant uh +improvement over you know complete + + align:start position:0% +improvement over you know complete + + + align:start position:0% +improvement over you know complete +serial computation so + + align:start position:0% +serial computation so + + + align:start position:0% +serial computation so +so it's sort of like a + + align:start position:0% +so it's sort of like a + + + align:start position:0% +so it's sort of like a +a wave front that's + + align:start position:0% +a wave front that's + + + align:start position:0% +a wave front that's +propagating outward + + align:start position:0% + + + + align:start position:0% + +so if we have some sort of initial + + align:start position:0% +so if we have some sort of initial + + + align:start position:0% +so if we have some sort of initial +conditions you can imagine that as the + + align:start position:0% +conditions you can imagine that as the + + + align:start position:0% +conditions you can imagine that as the +solutions progress + + align:start position:0% +solutions progress + + + align:start position:0% +solutions progress +we could keep them + + align:start position:0% +we could keep them + + + align:start position:0% +we could keep them +moving at more or less the same speed + + align:start position:0% +moving at more or less the same speed + + + align:start position:0% +moving at more or less the same speed +and then + + align:start position:0% +and then + + + align:start position:0% +and then +look at neighboring ones in order to + + align:start position:0% +look at neighboring ones in order to + + + align:start position:0% +look at neighboring ones in order to +improve and interpolate and what have + + align:start position:0% +improve and interpolate and what have + + + align:start position:0% +improve and interpolate and what have +you + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +um + + align:start position:0% +um + + + align:start position:0% +um +that means that they ought to move sort + + align:start position:0% +that means that they ought to move sort + + + align:start position:0% +that means that they ought to move sort +of at similar speeds so that gets us to + + align:start position:0% +of at similar speeds so that gets us to + + + align:start position:0% +of at similar speeds so that gets us to +this question of + + align:start position:0% +this question of + + + align:start position:0% +this question of +speed + + align:start position:0% + + + + align:start position:0% + +and i mean in terms of the numerical + + align:start position:0% +and i mean in terms of the numerical + + + align:start position:0% +and i mean in terms of the numerical +solution of these equations is just the + + align:start position:0% +solution of these equations is just the + + + align:start position:0% +solution of these equations is just the +step size you know what step size well + + align:start position:0% +step size you know what step size well + + + align:start position:0% +step size you know what step size well +clearly if the step size is a hundredth + + align:start position:0% +clearly if the step size is a hundredth + + + align:start position:0% +clearly if the step size is a hundredth +of a pixel + + align:start position:0% +of a pixel + + + align:start position:0% +of a pixel +that's overkill that's not going to work + + align:start position:0% +that's overkill that's not going to work + + + align:start position:0% +that's overkill that's not going to work +very well because the brightness doesn't + + align:start position:0% +very well because the brightness doesn't + + + align:start position:0% +very well because the brightness doesn't +change much in the hundredth of a pixel + + align:start position:0% +change much in the hundredth of a pixel + + + align:start position:0% +change much in the hundredth of a pixel +conversely if the step size is 100 + + align:start position:0% +conversely if the step size is 100 + + + align:start position:0% +conversely if the step size is 100 +pixels that's probably completely wrong + + align:start position:0% +pixels that's probably completely wrong + + + align:start position:0% +pixels that's probably completely wrong +because you're missing all of the + + align:start position:0% +because you're missing all of the + + + align:start position:0% +because you're missing all of the +in-between brightness variations + + align:start position:0% +in-between brightness variations + + + align:start position:0% +in-between brightness variations +so + + align:start position:0% +so + + + align:start position:0% +so +you'd like to have a reasonable step + + align:start position:0% +you'd like to have a reasonable step + + + align:start position:0% +you'd like to have a reasonable step +size and so let's look at + + align:start position:0% +size and so let's look at + + + align:start position:0% +size and so let's look at +what we can do in terms of controlling + + align:start position:0% +what we can do in terms of controlling + + + align:start position:0% +what we can do in terms of controlling +the step size + + align:start position:0% + + + + align:start position:0% + +and as i mentioned + + align:start position:0% +and as i mentioned + + + align:start position:0% +and as i mentioned +you know all we need to do really is + + align:start position:0% +you know all we need to do really is + + + align:start position:0% +you know all we need to do really is +multiply all of our equations by the + + align:start position:0% +multiply all of our equations by the + + + align:start position:0% +multiply all of our equations by the +same quantity and + + align:start position:0% +same quantity and + + + align:start position:0% +same quantity and +all it does is it changes the + + align:start position:0% +all it does is it changes the + + + align:start position:0% +all it does is it changes the +increment + + align:start position:0% +increment + + + align:start position:0% +increment +and so let's look at some simple cases + + align:start position:0% +and so let's look at some simple cases + + + align:start position:0% +and so let's look at some simple cases +so + + align:start position:0% +so + + + align:start position:0% +so +constant + + align:start position:0% +constant + + + align:start position:0% +constant +step size + + align:start position:0% +step size + + + align:start position:0% +step size +in + + align:start position:0% +in + + + align:start position:0% +in +z + + align:start position:0% + + + + align:start position:0% + +so that's interesting because that means + + align:start position:0% +so that's interesting because that means + + + align:start position:0% +so that's interesting because that means +that you're kind of stepping from + + align:start position:0% +that you're kind of stepping from + + + align:start position:0% +that you're kind of stepping from +contour to contour think of a contour + + align:start position:0% +contour to contour think of a contour + + + align:start position:0% +contour to contour think of a contour +map + + align:start position:0% +map + + + align:start position:0% +map +uh in if we implement that then these + + align:start position:0% +uh in if we implement that then these + + + align:start position:0% +uh in if we implement that then these +would be contours of constant height on + + align:start position:0% +would be contours of constant height on + + + align:start position:0% +would be contours of constant height on +the surface + + align:start position:0% +the surface + + + align:start position:0% +the surface +and what we're doing is + + align:start position:0% +and what we're doing is + + + align:start position:0% +and what we're doing is +all of these solutions as they grow + + align:start position:0% +all of these solutions as they grow + + + align:start position:0% +all of these solutions as they grow +are going from you know the contour at a + + align:start position:0% +are going from you know the contour at a + + + align:start position:0% +are going from you know the contour at a +thousand meters to the contour at 990 + + align:start position:0% +thousand meters to the contour at 990 + + + align:start position:0% +thousand meters to the contour at 990 +meters to the contour at 980 meters and + + align:start position:0% +meters to the contour at 980 meters and + + + align:start position:0% +meters to the contour at 980 meters and +so on + + align:start position:0% +so on + + + align:start position:0% +so on +and so that's a + + align:start position:0% +and so that's a + + + align:start position:0% +and so that's a +interesting and useful way of + + align:start position:0% +interesting and useful way of + + + align:start position:0% +interesting and useful way of +controlling the step size and what do we + + align:start position:0% +controlling the step size and what do we + + + align:start position:0% +controlling the step size and what do we +need to do that well we've got + + align:start position:0% +need to do that well we've got + + + align:start position:0% +need to do that well we've got +p r p plus q r q + + align:start position:0% +p r p plus q r q + + + align:start position:0% +p r p plus q r q +in the equation for z which just + + align:start position:0% +in the equation for z which just + + + align:start position:0% +in the equation for z which just +disappeared + + align:start position:0% +disappeared + + + align:start position:0% +disappeared +and so we just divide by that + + align:start position:0% + + + + align:start position:0% + +uh why is that well because then dz d + + align:start position:0% +uh why is that well because then dz d + + + align:start position:0% +uh why is that well because then dz d +let's + + align:start position:0% +let's + + + align:start position:0% +let's +call it + + align:start position:0% +call it + + + align:start position:0% +call it +psi + + align:start position:0% +psi + + + align:start position:0% +psi +dash is one + + align:start position:0% +dash is one + + + align:start position:0% +dash is one +right so we had this equation over here + + align:start position:0% +right so we had this equation over here + + + align:start position:0% +right so we had this equation over here +d + + align:start position:0% +d + + + align:start position:0% +d +c d psi is + + align:start position:0% +c d psi is + + + align:start position:0% +c d psi is +p r p plus q r q + + align:start position:0% +p r p plus q r q + + + align:start position:0% +p r p plus q r q +now if we just divide by that then the + + align:start position:0% +now if we just divide by that then the + + + align:start position:0% +now if we just divide by that then the +rate of change is uh the derivative is + + align:start position:0% +rate of change is uh the derivative is + + + align:start position:0% +rate of change is uh the derivative is +one and that means that we have constant + + align:start position:0% +one and that means that we have constant + + + align:start position:0% +one and that means that we have constant +increments in the z direction of course + + align:start position:0% +increments in the z direction of course + + + align:start position:0% +increments in the z direction of course +we have to + + align:start position:0% +we have to + + + align:start position:0% +we have to +multiply or divide all of the other + + align:start position:0% +multiply or divide all of the other + + + align:start position:0% +multiply or divide all of the other +equations by the same factor so that's + + align:start position:0% +equations by the same factor so that's + + + align:start position:0% +equations by the same factor so that's +sort of an easy to visualize + + align:start position:0% +sort of an easy to visualize + + + align:start position:0% +sort of an easy to visualize +change that has potential benefits + + align:start position:0% +change that has potential benefits + + + align:start position:0% +change that has potential benefits +we just multiply all of the divide all + + align:start position:0% +we just multiply all of the divide all + + + align:start position:0% +we just multiply all of the divide all +of the equations by that and then we're + + align:start position:0% +of the equations by that and then we're + + + align:start position:0% +of the equations by that and then we're +stepping uh from contour to contour as + + align:start position:0% +stepping uh from contour to contour as + + + align:start position:0% +stepping uh from contour to contour as +we explore the surface + + align:start position:0% +we explore the surface + + + align:start position:0% +we explore the surface +and + + align:start position:0% +and + + + align:start position:0% +and +that sort of makes it + + align:start position:0% +that sort of makes it + + + align:start position:0% +that sort of makes it +a little clearer how + + align:start position:0% +a little clearer how + + + align:start position:0% +a little clearer how +how we're exploring the surface + + align:start position:0% +how we're exploring the surface + + + align:start position:0% +how we're exploring the surface +okay + + align:start position:0% + + + + align:start position:0% + +but we can + + align:start position:0% +but we can + + + align:start position:0% +but we can +pick something else + + align:start position:0% +pick something else + + + align:start position:0% +pick something else +for example + + align:start position:0% +for example + + + align:start position:0% +for example +we were talking about + + align:start position:0% +we were talking about + + + align:start position:0% +we were talking about +steps in terms of pixels so + + align:start position:0% +steps in terms of pixels so + + + align:start position:0% +steps in terms of pixels so +secondly we can look at + + align:start position:0% +secondly we can look at + + + align:start position:0% +secondly we can look at +constant + + align:start position:0% +constant + + + align:start position:0% +constant +step size in image + + align:start position:0% + + + + align:start position:0% + +so we want delta x squared plus delta y + + align:start position:0% +so we want delta x squared plus delta y + + + align:start position:0% +so we want delta x squared plus delta y +squared to be a constant and those are + + align:start position:0% +squared to be a constant and those are + + + align:start position:0% +squared to be a constant and those are +proportional to r p and r q + + align:start position:0% +proportional to r p and r q + + + align:start position:0% +proportional to r p and r q +so we divide by + + align:start position:0% + + + + align:start position:0% + +i shouldn't have wiped out these + + align:start position:0% +i shouldn't have wiped out these + + + align:start position:0% +i shouldn't have wiped out these +equations yet because + + align:start position:0% +equations yet because + + + align:start position:0% +equations yet because +it's handy to + + align:start position:0% +it's handy to + + + align:start position:0% +it's handy to +have them + + align:start position:0% +have them + + + align:start position:0% +have them +at this point dxt + + align:start position:0% + + + + align:start position:0% + +so that assures that um the square root + + align:start position:0% +so that assures that um the square root + + + align:start position:0% +so that assures that um the square root +of delta x squared plus delta y squared + + align:start position:0% +of delta x squared plus delta y squared + + + align:start position:0% +of delta x squared plus delta y squared +is going to be constant if you like make + + align:start position:0% +is going to be constant if you like make + + + align:start position:0% +is going to be constant if you like make +it one + + align:start position:0% +it one + + + align:start position:0% +it one +and + + align:start position:0% + + + + align:start position:0% + +oh + + align:start position:0% + + + + align:start position:0% + +okay so that's another way where instead + + align:start position:0% +okay so that's another way where instead + + + align:start position:0% +okay so that's another way where instead +of moving in constant increments in + + align:start position:0% +of moving in constant increments in + + + align:start position:0% +of moving in constant increments in +height + + align:start position:0% +height + + + align:start position:0% +height +uh the intervals in the image are uh + + align:start position:0% +uh the intervals in the image are uh + + + align:start position:0% +uh the intervals in the image are uh +fixed in size and and + + align:start position:0% +fixed in size and and + + + align:start position:0% +fixed in size and and +well a couple of issues with that one of + + align:start position:0% +well a couple of issues with that one of + + + align:start position:0% +well a couple of issues with that one of +them is + + align:start position:0% +them is + + + align:start position:0% +them is +that those + + align:start position:0% +that those + + + align:start position:0% +that those +curves + + align:start position:0% +curves + + + align:start position:0% +curves +may + + align:start position:0% +may + + + align:start position:0% +may +uh run at different rates so that one of + + align:start position:0% +uh run at different rates so that one of + + + align:start position:0% +uh run at different rates so that one of +the curves is sort of getting ahead of + + align:start position:0% +the curves is sort of getting ahead of + + + align:start position:0% +the curves is sort of getting ahead of +the other + + align:start position:0% +the other + + + align:start position:0% +the other +because we're not tying them together in + + align:start position:0% +because we're not tying them together in + + + align:start position:0% +because we're not tying them together in +height or anything we're only tying them + + align:start position:0% +height or anything we're only tying them + + + align:start position:0% +height or anything we're only tying them +together in how far are we from where we + + align:start position:0% +together in how far are we from where we + + + align:start position:0% +together in how far are we from where we +started + + align:start position:0% +started + + + align:start position:0% +started +so that's a problem and then another + + align:start position:0% +so that's a problem and then another + + + align:start position:0% +so that's a problem and then another +problem is + + align:start position:0% + + + + align:start position:0% + +um we're going to divide by that because + + align:start position:0% +um we're going to divide by that because + + + align:start position:0% +um we're going to divide by that because +if that's zero then + + align:start position:0% +if that's zero then + + + align:start position:0% +if that's zero then +we're out to lunch so and i make a note + + align:start position:0% +we're out to lunch so and i make a note + + + align:start position:0% +we're out to lunch so and i make a note +of that now because we'll need that in a + + align:start position:0% +of that now because we'll need that in a + + + align:start position:0% +of that now because we'll need that in a +minute + + align:start position:0% +minute + + + align:start position:0% +minute +okay constant size steps in the image + + align:start position:0% +okay constant size steps in the image + + + align:start position:0% +okay constant size steps in the image +how about constant size steps in 3d + + align:start position:0% + + + + align:start position:0% + +so that means we want + + align:start position:0% + + + + align:start position:0% + +that to be one + + align:start position:0% + + + + align:start position:0% + +and so that means we need to divide by + + align:start position:0% + + + + align:start position:0% + +by that quantity + + align:start position:0% +by that quantity + + + align:start position:0% +by that quantity +and so for that where's that come from + + align:start position:0% +and so for that where's that come from + + + align:start position:0% +and so for that where's that come from +uh that's that's this thing here so this + + align:start position:0% +uh that's that's this thing here so this + + + align:start position:0% +uh that's that's this thing here so this +gives us delta x this gives us delta y + + align:start position:0% +gives us delta x this gives us delta y + + + align:start position:0% +gives us delta x this gives us delta y +this gives us delta z + + align:start position:0% +this gives us delta z + + + align:start position:0% +this gives us delta z +and if we want + + align:start position:0% +and if we want + + + align:start position:0% +and if we want +the sum of the squares of those to be 1 + + align:start position:0% +the sum of the squares of those to be 1 + + + align:start position:0% +the sum of the squares of those to be 1 +then + + align:start position:0% +then + + + align:start position:0% +then +we divide by that and again this has the + + align:start position:0% +we divide by that and again this has the + + + align:start position:0% +we divide by that and again this has the +same + + align:start position:0% + + + + align:start position:0% + +problem or special case + + align:start position:0% + + + + align:start position:0% + +that if rp and rq are zero then that is + + align:start position:0% +that if rp and rq are zero then that is + + + align:start position:0% +that if rp and rq are zero then that is +zero and so on + + align:start position:0% + + + + align:start position:0% + +so how about + + align:start position:0% + + + + align:start position:0% + +if we step + + align:start position:0% +if we step + + + align:start position:0% +if we step +in isophodes in contours in the image of + + align:start position:0% +in isophodes in contours in the image of + + + align:start position:0% +in isophodes in contours in the image of +contrast of brightness so + + align:start position:0% +contrast of brightness so + + + align:start position:0% +contrast of brightness so +here we + + align:start position:0% +here we + + + align:start position:0% +here we +had contours on the surface + + align:start position:0% +had contours on the surface + + + align:start position:0% +had contours on the surface +z was the + + align:start position:0% +z was the + + + align:start position:0% +z was the +constant along each of those + + align:start position:0% +constant along each of those + + + align:start position:0% +constant along each of those +curves but it might be interesting to + + align:start position:0% +curves but it might be interesting to + + + align:start position:0% +curves but it might be interesting to +step in the image from one brightness + + align:start position:0% +step in the image from one brightness + + + align:start position:0% +step in the image from one brightness +level to another so + + align:start position:0% +level to another so + + + align:start position:0% +level to another so +um well + + align:start position:0% + + + + align:start position:0% + +i won't go + + align:start position:0% +i won't go + + + align:start position:0% +i won't go +too much into detail of that but + + align:start position:0% + + + + align:start position:0% + +we basically then have to divide by that + + align:start position:0% +we basically then have to divide by that + + + align:start position:0% +we basically then have to divide by that +quantity + + align:start position:0% +quantity + + + align:start position:0% +quantity +and + + align:start position:0% +and + + + align:start position:0% +and +that sort of + + align:start position:0% + + + + align:start position:0% + +remember the two gradients the one in + + align:start position:0% +remember the two gradients the one in + + + align:start position:0% +remember the two gradients the one in +the + + align:start position:0% +the + + + align:start position:0% +the +in the image and the other one in the + + align:start position:0% +in the image and the other one in the + + + align:start position:0% +in the image and the other one in the +reflectance map well that's the dot + + align:start position:0% +reflectance map well that's the dot + + + align:start position:0% +reflectance map well that's the dot +product of those two but + + align:start position:0% +product of those two but + + + align:start position:0% +product of those two but +i don't know if that means anything but + + align:start position:0% +i don't know if that means anything but + + + align:start position:0% +i don't know if that means anything but +it's just + + align:start position:0% +it's just + + + align:start position:0% +it's just +interesting to note and we won't go into + + align:start position:0% +interesting to note and we won't go into + + + align:start position:0% +interesting to note and we won't go into +too much detail but obviously that's + + align:start position:0% +too much detail but obviously that's + + + align:start position:0% +too much detail but obviously that's +another interesting uh + + align:start position:0% +another interesting uh + + + align:start position:0% +another interesting uh +speed control + + align:start position:0% +speed control + + + align:start position:0% +speed control +in that we're moving from contour to + + align:start position:0% +in that we're moving from contour to + + + align:start position:0% +in that we're moving from contour to +contour in the image and you know one + + align:start position:0% +contour in the image and you know one + + + align:start position:0% +contour in the image and you know one +advantage of some of these is that they + + align:start position:0% +advantage of some of these is that they + + + align:start position:0% +advantage of some of these is that they +tend to make it easier to tie together + + align:start position:0% +tend to make it easier to tie together + + + align:start position:0% +tend to make it easier to tie together +neighboring solutions so in this case + + align:start position:0% +neighboring solutions so in this case + + + align:start position:0% +neighboring solutions so in this case +these + + align:start position:0% +these + + + align:start position:0% +these +curves these wave fronts would be just + + align:start position:0% +curves these wave fronts would be just + + + align:start position:0% +curves these wave fronts would be just +isophodes in the image plane + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +and you know in terms of + + align:start position:0% +and you know in terms of + + + align:start position:0% +and you know in terms of +the + + align:start position:0% +the + + + align:start position:0% +the +numerical analysis aspect of it + + align:start position:0% +numerical analysis aspect of it + + + align:start position:0% +numerical analysis aspect of it +again we're not doing any fancy methods + + align:start position:0% +again we're not doing any fancy methods + + + align:start position:0% +again we're not doing any fancy methods +for solving ordinary differential + + align:start position:0% +for solving ordinary differential + + + align:start position:0% +for solving ordinary differential +equation we're just saying you know if + + align:start position:0% +equation we're just saying you know if + + + align:start position:0% +equation we're just saying you know if +the slope is m and we take a step delta + + align:start position:0% +the slope is m and we take a step delta + + + align:start position:0% +the slope is m and we take a step delta +then the change is m times delta + + align:start position:0% +then the change is m times delta + + + align:start position:0% +then the change is m times delta +which is you know the lowest order + + align:start position:0% +which is you know the lowest order + + + align:start position:0% +which is you know the lowest order +crudest thing you can do + + align:start position:0% +crudest thing you can do + + + align:start position:0% +crudest thing you can do +but + + align:start position:0% +but + + + align:start position:0% +but +as i mentioned we don't really + + align:start position:0% +as i mentioned we don't really + + + align:start position:0% +as i mentioned we don't really +expect to get much better by using + + align:start position:0% +expect to get much better by using + + + align:start position:0% +expect to get much better by using +something very sophisticated + + align:start position:0% + + + + align:start position:0% + +you may have heard that there's a + + align:start position:0% +you may have heard that there's a + + + align:start position:0% +you may have heard that there's a +result recently about three bodies so + + align:start position:0% +result recently about three bodies so + + + align:start position:0% +result recently about three bodies so +you all know that if you have two bodies + + align:start position:0% +you all know that if you have two bodies + + + align:start position:0% +you all know that if you have two bodies +then they orbit + + align:start position:0% +then they orbit + + + align:start position:0% +then they orbit +in elliptical fashion and the ellipses + + align:start position:0% +in elliptical fashion and the ellipses + + + align:start position:0% +in elliptical fashion and the ellipses +are stable and you know all that good + + align:start position:0% +are stable and you know all that good + + + align:start position:0% +are stable and you know all that good +stuff from + + align:start position:0% +stuff from + + + align:start position:0% +stuff from +starting from newton and kepler and + + align:start position:0% +starting from newton and kepler and + + + align:start position:0% +starting from newton and kepler and +copernicus and so on if you have three + + align:start position:0% +copernicus and so on if you have three + + + align:start position:0% +copernicus and so on if you have three +bodies + + align:start position:0% +bodies + + + align:start position:0% +bodies +uh + + align:start position:0% +uh + + + align:start position:0% +uh +chaos ensues + + align:start position:0% +chaos ensues + + + align:start position:0% +chaos ensues +uh all sorts of things can happen and + + align:start position:0% +uh all sorts of things can happen and + + + align:start position:0% +uh all sorts of things can happen and +mostly the orbits are not periodic and + + align:start position:0% +mostly the orbits are not periodic and + + + align:start position:0% +mostly the orbits are not periodic and +so even if you want to know suppose you + + align:start position:0% +so even if you want to know suppose you + + + align:start position:0% +so even if you want to know suppose you +live in a world with three suns and + + align:start position:0% +live in a world with three suns and + + + align:start position:0% +live in a world with three suns and +they're orbiting each other then suppose + + align:start position:0% +they're orbiting each other then suppose + + + align:start position:0% +they're orbiting each other then suppose +you want to know whether + + align:start position:0% +you want to know whether + + + align:start position:0% +you want to know whether +at some point one of them will run into + + align:start position:0% +at some point one of them will run into + + + align:start position:0% +at some point one of them will run into +another and blow up your world um + + align:start position:0% +another and blow up your world um + + + align:start position:0% +another and blow up your world um +it's uh + + align:start position:0% +it's uh + + + align:start position:0% +it's uh +there's no periodicity so you can't use + + align:start position:0% +there's no periodicity so you can't use + + + align:start position:0% +there's no periodicity so you can't use +simple method anyway there's a wonderful + + align:start position:0% +simple method anyway there's a wonderful + + + align:start position:0% +simple method anyway there's a wonderful +science fiction book called the + + align:start position:0% +science fiction book called the + + + align:start position:0% +science fiction book called the +three-body problem + + align:start position:0% +three-body problem + + + align:start position:0% +three-body problem +where people live on in such a place + + align:start position:0% +where people live on in such a place + + + align:start position:0% +where people live on in such a place +and + + align:start position:0% +and + + + align:start position:0% +and +curiously just recently someone has + + align:start position:0% +curiously just recently someone has + + + align:start position:0% +curiously just recently someone has +actually put to good use one of these + + align:start position:0% +actually put to good use one of these + + + align:start position:0% +actually put to good use one of these +gigantic super computers so you know + + align:start position:0% +gigantic super computers so you know + + + align:start position:0% +gigantic super computers so you know +nations compete with each other in + + align:start position:0% +nations compete with each other in + + + align:start position:0% +nations compete with each other in +various stupid ways and one of them is + + align:start position:0% +various stupid ways and one of them is + + + align:start position:0% +various stupid ways and one of them is +you know i can build a bigger computer + + align:start position:0% +you know i can build a bigger computer + + + align:start position:0% +you know i can build a bigger computer +than you + + align:start position:0% +than you + + + align:start position:0% +than you +and so periodically you know the us has + + align:start position:0% +and so periodically you know the us has + + + align:start position:0% +and so periodically you know the us has +the biggest and then i don't know japan + + align:start position:0% +the biggest and then i don't know japan + + + align:start position:0% +the biggest and then i don't know japan +and then china so i i think at this + + align:start position:0% +and then china so i i think at this + + + align:start position:0% +and then china so i i think at this +point it might be china anyway a lot of + + align:start position:0% +point it might be china anyway a lot of + + + align:start position:0% +point it might be china anyway a lot of +times then you ask well okay they got + + align:start position:0% +times then you ask well okay they got + + + align:start position:0% +times then you ask well okay they got +this fantastic computer + + align:start position:0% +this fantastic computer + + + align:start position:0% +this fantastic computer +what are they getting out of it and well + + align:start position:0% +what are they getting out of it and well + + + align:start position:0% +what are they getting out of it and well +you can do some things you can do + + align:start position:0% +you can do some things you can do + + + align:start position:0% +you can do some things you can do +weather simulations better than anyone + + align:start position:0% +weather simulations better than anyone + + + align:start position:0% +weather simulations better than anyone +else you can + + align:start position:0% +else you can + + + align:start position:0% +else you can +you can solve some quantum equations of + + align:start position:0% +you can solve some quantum equations of + + + align:start position:0% +you can solve some quantum equations of +you know more than one particle uh on it + + align:start position:0% +you know more than one particle uh on it + + + align:start position:0% +you know more than one particle uh on it +well what he did this person + + align:start position:0% +well what he did this person + + + align:start position:0% +well what he did this person +was the three-body problem + + align:start position:0% +was the three-body problem + + + align:start position:0% +was the three-body problem +and so he was interested in finding + + align:start position:0% +and so he was interested in finding + + + align:start position:0% +and so he was interested in finding +periodic solutions and for a hundred + + align:start position:0% +periodic solutions and for a hundred + + + align:start position:0% +periodic solutions and for a hundred +years + + align:start position:0% +years + + + align:start position:0% +years +uh it's been known that there's some + + align:start position:0% +uh it's been known that there's some + + + align:start position:0% +uh it's been known that there's some +periodic solutions but they were very + + align:start position:0% +periodic solutions but they were very + + + align:start position:0% +periodic solutions but they were very +special you know things go in particular + + align:start position:0% +special you know things go in particular + + + align:start position:0% +special you know things go in particular +figure eight patterns and s asteroid uh + + align:start position:0% +figure eight patterns and s asteroid uh + + + align:start position:0% +figure eight patterns and s asteroid uh +orbits + + align:start position:0% +orbits + + + align:start position:0% +orbits +and + + align:start position:0% +and + + + align:start position:0% +and +but there's a very small number of these + + align:start position:0% +but there's a very small number of these + + + align:start position:0% +but there's a very small number of these +solutions known i forget what i don't + + align:start position:0% +solutions known i forget what i don't + + + align:start position:0% +solutions known i forget what i don't +know six or something well he used this + + align:start position:0% +know six or something well he used this + + + align:start position:0% +know six or something well he used this +supercomputer to find uh i don't know 68 + + align:start position:0% +supercomputer to find uh i don't know 68 + + + align:start position:0% +supercomputer to find uh i don't know 68 +and you know it's amazing it's fantastic + + align:start position:0% +and you know it's amazing it's fantastic + + + align:start position:0% +and you know it's amazing it's fantastic +they're wonderful orbits + + align:start position:0% +they're wonderful orbits + + + align:start position:0% +they're wonderful orbits +and you might say well wait a minute uh + + align:start position:0% +and you might say well wait a minute uh + + + align:start position:0% +and you might say well wait a minute uh +this is really something that should be + + align:start position:0% +this is really something that should be + + + align:start position:0% +this is really something that should be +done analytically because + + align:start position:0% +done analytically because + + + align:start position:0% +done analytically because +you know you can do the numerical + + align:start position:0% +you know you can do the numerical + + + align:start position:0% +you know you can do the numerical +simulation but how do you know that it's + + align:start position:0% +simulation but how do you know that it's + + + align:start position:0% +simulation but how do you know that it's +really really periodic + + align:start position:0% +really really periodic + + + align:start position:0% +really really periodic +well + + align:start position:0% +well + + + align:start position:0% +well +having this supercomputer he is able to + + align:start position:0% +having this supercomputer he is able to + + + align:start position:0% +having this supercomputer he is able to +do things that mere mortals wouldn't + + align:start position:0% +do things that mere mortals wouldn't + + + align:start position:0% +do things that mere mortals wouldn't +normally do + + align:start position:0% +normally do + + + align:start position:0% +normally do +like you know approximate the taylor + + align:start position:0% +like you know approximate the taylor + + + align:start position:0% +like you know approximate the taylor +series to + + align:start position:0% +series to + + + align:start position:0% +series to +a thousand terms you know you'd usually + + align:start position:0% +a thousand terms you know you'd usually + + + align:start position:0% +a thousand terms you know you'd usually +stop at two or three + + align:start position:0% +stop at two or three + + + align:start position:0% +stop at two or three +and maybe if you on the computer you + + align:start position:0% +and maybe if you on the computer you + + + align:start position:0% +and maybe if you on the computer you +might do i don't know eight + + align:start position:0% +might do i don't know eight + + + align:start position:0% +might do i don't know eight +but he didn't stop at any particular + + align:start position:0% +but he didn't stop at any particular + + + align:start position:0% +but he didn't stop at any particular +point he simply kept on adding until he + + align:start position:0% +point he simply kept on adding until he + + + align:start position:0% +point he simply kept on adding until he +didn't need to go any further and the + + align:start position:0% +didn't need to go any further and the + + + align:start position:0% +didn't need to go any further and the +same with the calculations the uh you + + align:start position:0% +same with the calculations the uh you + + + align:start position:0% +same with the calculations the uh you +know eighth order range cutter that's a + + align:start position:0% +know eighth order range cutter that's a + + + align:start position:0% +know eighth order range cutter that's a +very sophisticated method for solving + + align:start position:0% +very sophisticated method for solving + + + align:start position:0% +very sophisticated method for solving +odes well he used thousand order + + align:start position:0% +odes well he used thousand order + + + align:start position:0% +odes well he used thousand order +and + + align:start position:0% +and + + + align:start position:0% +and +uh in the process + + align:start position:0% +uh in the process + + + align:start position:0% +uh in the process +he discovered uh these periodic orbits + + align:start position:0% +he discovered uh these periodic orbits + + + align:start position:0% +he discovered uh these periodic orbits +anyway + + align:start position:0% +anyway + + + align:start position:0% +anyway +where was it going with this well the + + align:start position:0% +where was it going with this well the + + + align:start position:0% +where was it going with this well the +point is that + + align:start position:0% +point is that + + + align:start position:0% +point is that +there are very sophisticated methods for + + align:start position:0% +there are very sophisticated methods for + + + align:start position:0% +there are very sophisticated methods for +numerically solving equations + + align:start position:0% +numerically solving equations + + + align:start position:0% +numerically solving equations +and if you're trying to say for example + + align:start position:0% +and if you're trying to say for example + + + align:start position:0% +and if you're trying to say for example +figure out how long our solar system is + + align:start position:0% +figure out how long our solar system is + + + align:start position:0% +figure out how long our solar system is +stable + + align:start position:0% +stable + + + align:start position:0% +stable +you it's very difficult you need to use + + align:start position:0% +you it's very difficult you need to use + + + align:start position:0% +you it's very difficult you need to use +much more sophisticated methods than we + + align:start position:0% +much more sophisticated methods than we + + + align:start position:0% +much more sophisticated methods than we +do + + align:start position:0% +do + + + align:start position:0% +do +and + + align:start position:0% +and + + + align:start position:0% +and +you know gerald sussman actually built a + + align:start position:0% +you know gerald sussman actually built a + + + align:start position:0% +you know gerald sussman actually built a +machine to do that + + align:start position:0% +machine to do that + + + align:start position:0% +machine to do that +but it's + + align:start position:0% +but it's + + + align:start position:0% +but it's +because it's chaotic you can't be sure + + align:start position:0% +because it's chaotic you can't be sure + + + align:start position:0% +because it's chaotic you can't be sure +but he can say that + + align:start position:0% +but he can say that + + + align:start position:0% +but he can say that +nothing bad is going to happen in the + + align:start position:0% +nothing bad is going to happen in the + + + align:start position:0% +nothing bad is going to happen in the +next 100 million years so you can rest + + align:start position:0% +next 100 million years so you can rest + + + align:start position:0% +next 100 million years so you can rest +assured that things will be fairly safe + + align:start position:0% +assured that things will be fairly safe + + + align:start position:0% +assured that things will be fairly safe +fortunately we have a case where we + + align:start position:0% +fortunately we have a case where we + + + align:start position:0% +fortunately we have a case where we +don't need to have anything like that + + align:start position:0% +don't need to have anything like that + + + align:start position:0% +don't need to have anything like that +kind of numerical precision + + align:start position:0% +kind of numerical precision + + + align:start position:0% +kind of numerical precision +okay um we do need an initial curve + + align:start position:0% +okay um we do need an initial curve + + + align:start position:0% +okay um we do need an initial curve +though so let's talk about which is a + + align:start position:0% +though so let's talk about which is a + + + align:start position:0% +though so let's talk about which is a +nuisance + + align:start position:0% +nuisance + + + align:start position:0% +nuisance +right because + + align:start position:0% + + + + align:start position:0% + +you know the whole point is to explore + + align:start position:0% +you know the whole point is to explore + + + align:start position:0% +you know the whole point is to explore +the surface using + + align:start position:0% +the surface using + + + align:start position:0% +the surface using +optical machine vision methods not + + align:start position:0% +optical machine vision methods not + + + align:start position:0% +optical machine vision methods not +not go there with a measuring tape and + + align:start position:0% +not go there with a measuring tape and + + + align:start position:0% +not go there with a measuring tape and +so having an initial curve + + align:start position:0% + + + + align:start position:0% + +is kind of not desirable i mean it's uh + + align:start position:0% +is kind of not desirable i mean it's uh + + + align:start position:0% +is kind of not desirable i mean it's uh +it's better than actually having to + + align:start position:0% +it's better than actually having to + + + align:start position:0% +it's better than actually having to +measure the whole surface because you're + + align:start position:0% +measure the whole surface because you're + + + align:start position:0% +measure the whole surface because you're +only measuring one curve on it and then + + align:start position:0% +only measuring one curve on it and then + + + align:start position:0% +only measuring one curve on it and then +the rest is filled in using the image + + align:start position:0% +the rest is filled in using the image + + + align:start position:0% +the rest is filled in using the image +but actually here we have an even worse + + align:start position:0% +but actually here we have an even worse + + + align:start position:0% +but actually here we have an even worse +problem + + align:start position:0% + + + + align:start position:0% + +which is we're carrying along not just x + + align:start position:0% +which is we're carrying along not just x + + + align:start position:0% +which is we're carrying along not just x +y and z but we're carrying along + + align:start position:0% +y and z but we're carrying along + + + align:start position:0% +y and z but we're carrying along +orientation as well so + + align:start position:0% +orientation as well so + + + align:start position:0% +orientation as well so +we get these characteristic strips so + + align:start position:0% +we get these characteristic strips so + + + align:start position:0% +we get these characteristic strips so +shouldn't it also be an initial strip + + align:start position:0% +shouldn't it also be an initial strip + + + align:start position:0% +shouldn't it also be an initial strip +in other words you know we're not just + + align:start position:0% +in other words you know we're not just + + + align:start position:0% +in other words you know we're not just +going to be forced to supply + + align:start position:0% +going to be forced to supply + + + align:start position:0% +going to be forced to supply +x + + align:start position:0% +x + + + align:start position:0% +x +y + + align:start position:0% +y + + + align:start position:0% +y +and z + + align:start position:0% +and z + + + align:start position:0% +and z +but + + align:start position:0% +but + + + align:start position:0% +but +you know that makes it even worse that + + align:start position:0% +you know that makes it even worse that + + + align:start position:0% +you know that makes it even worse that +means you have to measure that curve and + + align:start position:0% +means you have to measure that curve and + + + align:start position:0% +means you have to measure that curve and +also at every point on the curve + + align:start position:0% +also at every point on the curve + + + align:start position:0% +also at every point on the curve +measure the orientation + + align:start position:0% +measure the orientation + + + align:start position:0% +measure the orientation +well fortunately + + align:start position:0% +well fortunately + + + align:start position:0% +well fortunately +that's not + + align:start position:0% +that's not + + + align:start position:0% +that's not +necessary + + align:start position:0% +necessary + + + align:start position:0% +necessary +and there are two reasons for that one + + align:start position:0% +and there are two reasons for that one + + + align:start position:0% +and there are two reasons for that one +is + + align:start position:0% +is + + + align:start position:0% +is +that on the initial curve + + align:start position:0% +that on the initial curve + + + align:start position:0% +that on the initial curve +we have the image irradiance equation + + align:start position:0% +we have the image irradiance equation + + + align:start position:0% +we have the image irradiance equation +so we have e of x y + + align:start position:0% +so we have e of x y + + + align:start position:0% +so we have e of x y +is r of pq + + align:start position:0% + + + + align:start position:0% + +or you know + + align:start position:0% +or you know + + + align:start position:0% +or you know +you you're on the curve you look in the + + align:start position:0% +you you're on the curve you look in the + + + align:start position:0% +you you're on the curve you look in the +image what's the brightness there + + align:start position:0% +image what's the brightness there + + + align:start position:0% +image what's the brightness there +doesn't tell you the orientation but it + + align:start position:0% +doesn't tell you the orientation but it + + + align:start position:0% +doesn't tell you the orientation but it +gives you one constraint on the + + align:start position:0% +gives you one constraint on the + + + align:start position:0% +gives you one constraint on the +orientation + + align:start position:0% +orientation + + + align:start position:0% +orientation +and if we look at our reflectance map + + align:start position:0% +and if we look at our reflectance map + + + align:start position:0% +and if we look at our reflectance map +then it means we're you know we're on + + align:start position:0% +then it means we're you know we're on + + + align:start position:0% +then it means we're you know we're on +some curve + + align:start position:0% +some curve + + + align:start position:0% +some curve +so we have one constraint + + align:start position:0% +so we have one constraint + + + align:start position:0% +so we have one constraint +so we + + align:start position:0% +so we + + + align:start position:0% +so we +it's not like it could be any p and q it + + align:start position:0% +it's not like it could be any p and q it + + + align:start position:0% +it's not like it could be any p and q it +has to be one of those but then the + + align:start position:0% +has to be one of those but then the + + + align:start position:0% +has to be one of those but then the +other thing is that + + align:start position:0% +other thing is that + + + align:start position:0% +other thing is that +we have this curve and we're told that + + align:start position:0% +we have this curve and we're told that + + + align:start position:0% +we have this curve and we're told that +that curve's actually in the surface + + align:start position:0% +that curve's actually in the surface + + + align:start position:0% +that curve's actually in the surface +so that means that if i differentiate + + align:start position:0% + + + + align:start position:0% + +dz d theta should be + + align:start position:0% +dz d theta should be + + + align:start position:0% +dz d theta should be +p dx theta plus q + + align:start position:0% + + + + align:start position:0% + +right by the chain rule of course p is + + align:start position:0% +right by the chain rule of course p is + + + align:start position:0% +right by the chain rule of course p is +dz dx + + align:start position:0% +dz dx + + + align:start position:0% +dz dx +and q is dz dy + + align:start position:0% + + + + align:start position:0% + +and since i'm since someone magically + + align:start position:0% +and since i'm since someone magically + + + align:start position:0% +and since i'm since someone magically +gave me this initial curve i can compute + + align:start position:0% +gave me this initial curve i can compute + + + align:start position:0% +gave me this initial curve i can compute +these derivatives dx data dydata + + align:start position:0% +these derivatives dx data dydata + + + align:start position:0% +these derivatives dx data dydata +decediator and + + align:start position:0% +decediator and + + + align:start position:0% +decediator and +amazingly this is a linear equation + + align:start position:0% + + + + align:start position:0% + +so what's my job my job is to + + align:start position:0% +so what's my job my job is to + + + align:start position:0% +so what's my job my job is to +recover the unknowns p and q + + align:start position:0% +recover the unknowns p and q + + + align:start position:0% +recover the unknowns p and q +and i have two equations two unknowns + + align:start position:0% +and i have two equations two unknowns + + + align:start position:0% +and i have two equations two unknowns +and so there we are + + align:start position:0% +and so there we are + + + align:start position:0% +and so there we are +i can solve + + align:start position:0% +i can solve + + + align:start position:0% +i can solve +for p and q + + align:start position:0% +for p and q + + + align:start position:0% +for p and q +well you might say + + align:start position:0% +well you might say + + + align:start position:0% +well you might say +this first equation is likely to be + + align:start position:0% +this first equation is likely to be + + + align:start position:0% +this first equation is likely to be +non-linear you know you look at + + align:start position:0% +non-linear you know you look at + + + align:start position:0% +non-linear you know you look at +lambertian equation + + align:start position:0% +lambertian equation + + + align:start position:0% +lambertian equation +but there's one linear equation + + align:start position:0% +but there's one linear equation + + + align:start position:0% +but there's one linear equation +so then by bazoot's theorem + + align:start position:0% +so then by bazoot's theorem + + + align:start position:0% +so then by bazoot's theorem +what matters is you know what order is + + align:start position:0% +what matters is you know what order is + + + align:start position:0% +what matters is you know what order is +this equation and if it's second order + + align:start position:0% +this equation and if it's second order + + + align:start position:0% +this equation and if it's second order +that means you might have as many as two + + align:start position:0% +that means you might have as many as two + + + align:start position:0% +that means you might have as many as two +solutions but two solutions is better + + align:start position:0% +solutions but two solutions is better + + + align:start position:0% +solutions but two solutions is better +than an infinite number of solutions so + + align:start position:0% +than an infinite number of solutions so + + + align:start position:0% +than an infinite number of solutions so +okay so + + align:start position:0% +okay so + + + align:start position:0% +okay so +in practice we don't really need + + align:start position:0% +in practice we don't really need + + + align:start position:0% +in practice we don't really need +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +an initial strip we can get along with + + align:start position:0% +an initial strip we can get along with + + + align:start position:0% +an initial strip we can get along with +an initial curve because we can find the + + align:start position:0% +an initial curve because we can find the + + + align:start position:0% +an initial curve because we can find the +orientation using those two equations + + align:start position:0% + + + + align:start position:0% + +okay but we'd really like to get rid of + + align:start position:0% +okay but we'd really like to get rid of + + + align:start position:0% +okay but we'd really like to get rid of +this initial curve business it's really + + align:start position:0% +this initial curve business it's really + + + align:start position:0% +this initial curve business it's really +annoying + + align:start position:0% +annoying + + + align:start position:0% +annoying +and so + + align:start position:0% +and so + + + align:start position:0% +and so +what do we do well we great + + align:start position:0% +what do we do well we great + + + align:start position:0% +what do we do well we great +if there were some special points + + align:start position:0% +if there were some special points + + + align:start position:0% +if there were some special points +on the object where we know the + + align:start position:0% +on the object where we know the + + + align:start position:0% +on the object where we know the +shape orientation you know something + + align:start position:0% +shape orientation you know something + + + align:start position:0% +shape orientation you know something +uh so + + align:start position:0% +uh so + + + align:start position:0% +uh so +um + + align:start position:0% +um + + + align:start position:0% +um +you know so here's our prototypical + + align:start position:0% +you know so here's our prototypical + + + align:start position:0% +you know so here's our prototypical +object + + align:start position:0% +object + + + align:start position:0% +object +and that the image of this prototypical + + align:start position:0% +and that the image of this prototypical + + + align:start position:0% +and that the image of this prototypical +object and so you know question arises + + align:start position:0% +object and so you know question arises + + + align:start position:0% +object and so you know question arises +are there some + + align:start position:0% +are there some + + + align:start position:0% +are there some +so in most places we don't really know + + align:start position:0% +so in most places we don't really know + + + align:start position:0% +so in most places we don't really know +what the orientation is like we go here + + align:start position:0% +what the orientation is like we go here + + + align:start position:0% +what the orientation is like we go here +and we measure brightness + + align:start position:0% +and we measure brightness + + + align:start position:0% +and we measure brightness +e i don't know 23 and we go to the + + align:start position:0% +e i don't know 23 and we go to the + + + align:start position:0% +e i don't know 23 and we go to the +reflectance map and we get a contour + + align:start position:0% +reflectance map and we get a contour + + + align:start position:0% +reflectance map and we get a contour +there's a constraint but we don't know + + align:start position:0% +there's a constraint but we don't know + + + align:start position:0% +there's a constraint but we don't know +what the orientation is so are there any + + align:start position:0% +what the orientation is so are there any + + + align:start position:0% +what the orientation is so are there any +places here where you could tell me what + + align:start position:0% +places here where you could tell me what + + + align:start position:0% +places here where you could tell me what +the surface normal is + + align:start position:0% +the surface normal is + + + align:start position:0% +the surface normal is +the edge right so um + + align:start position:0% +the edge right so um + + + align:start position:0% +the edge right so um +the thing i draw here i guess the + + align:start position:0% +the thing i draw here i guess the + + + align:start position:0% +the thing i draw here i guess the +official word is occluding boundary + + align:start position:0% + + + + align:start position:0% + +sometimes + + align:start position:0% +sometimes + + + align:start position:0% +sometimes +the image version of it is called + + align:start position:0% +the image version of it is called + + + align:start position:0% +the image version of it is called +silhouette + + align:start position:0% +silhouette + + + align:start position:0% +silhouette +why well because that's where the object + + align:start position:0% +why well because that's where the object + + + align:start position:0% +why well because that's where the object +curls around and + + align:start position:0% +curls around and + + + align:start position:0% +curls around and +the part over here is visible and then + + align:start position:0% +the part over here is visible and then + + + align:start position:0% +the part over here is visible and then +the part where it curled around is not + + align:start position:0% +the part where it curled around is not + + + align:start position:0% +the part where it curled around is not +visible and the terminator that + + align:start position:0% +visible and the terminator that + + + align:start position:0% +visible and the terminator that +separates them + + align:start position:0% +separates them + + + align:start position:0% +separates them +i can draw + + align:start position:0% +i can draw + + + align:start position:0% +i can draw +a surface normal perpendicular + + align:start position:0% +a surface normal perpendicular + + + align:start position:0% +a surface normal perpendicular +to this curve and the + + align:start position:0% +to this curve and the + + + align:start position:0% +to this curve and the +surface normal at that point on the + + align:start position:0% +surface normal at that point on the + + + align:start position:0% +surface normal at that point on the +object + + align:start position:0% +object + + + align:start position:0% +object +will be + + align:start position:0% +will be + + + align:start position:0% +will be +parallel to that + + align:start position:0% +parallel to that + + + align:start position:0% +parallel to that +so what i'm saying is that + + align:start position:0% +so what i'm saying is that + + + align:start position:0% +so what i'm saying is that +if i go all along the occluding boundary + + align:start position:0% +if i go all along the occluding boundary + + + align:start position:0% +if i go all along the occluding boundary +i can construct a vector in the image + + align:start position:0% +i can construct a vector in the image + + + align:start position:0% +i can construct a vector in the image +plane + + align:start position:0% + + + + align:start position:0% + +and + + align:start position:0% +and + + + align:start position:0% +and +on the object the corresponding surface + + align:start position:0% +on the object the corresponding surface + + + align:start position:0% +on the object the corresponding surface +normal will be parallel to that + + align:start position:0% +normal will be parallel to that + + + align:start position:0% +normal will be parallel to that +so that's different from other places + + align:start position:0% +so that's different from other places + + + align:start position:0% +so that's different from other places +where + + align:start position:0% +where + + + align:start position:0% +where +you know i i don't have + + align:start position:0% +you know i i don't have + + + align:start position:0% +you know i i don't have +local information on surface orientation + + align:start position:0% + + + + align:start position:0% + +so and of course in perspective + + align:start position:0% +so and of course in perspective + + + align:start position:0% +so and of course in perspective +projection it's a little different but + + align:start position:0% +projection it's a little different but + + + align:start position:0% +projection it's a little different but +we're talking about orthographic + + align:start position:0% +we're talking about orthographic + + + align:start position:0% +we're talking about orthographic +projections so + + align:start position:0% +projections so + + + align:start position:0% +projections so +okay so um + + align:start position:0% +okay so um + + + align:start position:0% +okay so um +i could perhaps use those as starting + + align:start position:0% +i could perhaps use those as starting + + + align:start position:0% +i could perhaps use those as starting +conditions i could you know start my + + align:start position:0% +conditions i could you know start my + + + align:start position:0% +conditions i could you know start my +solutions there + + align:start position:0% +solutions there + + + align:start position:0% +solutions there +well the problem is that + + align:start position:0% + + + + align:start position:0% + +the slope is infinite there right if you + + align:start position:0% +the slope is infinite there right if you + + + align:start position:0% +the slope is infinite there right if you +think about approaching that edge + + align:start position:0% +think about approaching that edge + + + align:start position:0% +think about approaching that edge +uh you fall off dz dz dx and dz ddy + + align:start position:0% +uh you fall off dz dz dx and dz ddy + + + align:start position:0% +uh you fall off dz dz dx and dz ddy +become infinite the slope is infinite so + + align:start position:0% +become infinite the slope is infinite so + + + align:start position:0% +become infinite the slope is infinite so +that's obviously going to be a problem + + align:start position:0% +that's obviously going to be a problem + + + align:start position:0% +that's obviously going to be a problem +if we try to somehow incorporate that in + + align:start position:0% +if we try to somehow incorporate that in + + + align:start position:0% +if we try to somehow incorporate that in +in an equation so + + align:start position:0% +in an equation so + + + align:start position:0% +in an equation so +what's interesting is that the ratio is + + align:start position:0% +what's interesting is that the ratio is + + + align:start position:0% +what's interesting is that the ratio is +is known + + align:start position:0% + + + + align:start position:0% + +right because the ratio just defines + + align:start position:0% +right because the ratio just defines + + + align:start position:0% +right because the ratio just defines +this direction + + align:start position:0% + + + + align:start position:0% + +and so it's a funny sort of thing where + + align:start position:0% +and so it's a funny sort of thing where + + + align:start position:0% +and so it's a funny sort of thing where +you know p and q are infinite whatever + + align:start position:0% +you know p and q are infinite whatever + + + align:start position:0% +you know p and q are infinite whatever +that means but we know their ratio but + + align:start position:0% +that means but we know their ratio but + + + align:start position:0% +that means but we know their ratio but +unfortunately it turns out that we can't + + align:start position:0% +unfortunately it turns out that we can't + + + align:start position:0% +unfortunately it turns out that we can't +use that + + align:start position:0% +use that + + + align:start position:0% +use that +you know we have these equations that + + align:start position:0% +you know we have these equations that + + + align:start position:0% +you know we have these equations that +tell us + + align:start position:0% +tell us + + + align:start position:0% +tell us +how p and q are changing as we take a + + align:start position:0% +how p and q are changing as we take a + + + align:start position:0% +how p and q are changing as we take a +step + + align:start position:0% +step + + + align:start position:0% +step +but if the slope is infinite + + align:start position:0% +but if the slope is infinite + + + align:start position:0% +but if the slope is infinite +then that that doesn't work so + + align:start position:0% +then that that doesn't work so + + + align:start position:0% +then that that doesn't work so +the occluding boundary tells us + + align:start position:0% +the occluding boundary tells us + + + align:start position:0% +the occluding boundary tells us +something but we can't start the + + align:start position:0% +something but we can't start the + + + align:start position:0% +something but we can't start the +solution there and we get back to using + + align:start position:0% +solution there and we get back to using + + + align:start position:0% +solution there and we get back to using +the occluding boundary + + align:start position:0% +the occluding boundary + + + align:start position:0% +the occluding boundary +so + + align:start position:0% +so + + + align:start position:0% +so +that's number one + + align:start position:0% +that's number one + + + align:start position:0% +that's number one +now number two + + align:start position:0% +now number two + + + align:start position:0% +now number two +is + + align:start position:0% + + + + align:start position:0% + +if we look at uh + + align:start position:0% +if we look at uh + + + align:start position:0% +if we look at uh +imagine the + + align:start position:0% +imagine the + + + align:start position:0% +imagine the +beach ball painted white and the sun is + + align:start position:0% +beach ball painted white and the sun is + + + align:start position:0% +beach ball painted white and the sun is +behind you and you're looking at it + + align:start position:0% +behind you and you're looking at it + + + align:start position:0% +behind you and you're looking at it +there'll be some spot on it that's + + align:start position:0% +there'll be some spot on it that's + + + align:start position:0% +there'll be some spot on it that's +brighter than any other spot + + align:start position:0% +brighter than any other spot + + + align:start position:0% +brighter than any other spot +and + + align:start position:0% +and + + + align:start position:0% +and +you can + + align:start position:0% +you can + + + align:start position:0% +you can +from your knowledge of ambition surfaces + + align:start position:0% +from your knowledge of ambition surfaces + + + align:start position:0% +from your knowledge of ambition surfaces +say right away what the surface + + align:start position:0% +say right away what the surface + + + align:start position:0% +say right away what the surface +orientation there is + + align:start position:0% +orientation there is + + + align:start position:0% +orientation there is +right + + align:start position:0% + + + + align:start position:0% + +right because it's + + align:start position:0% +right because it's + + + align:start position:0% +right because it's +brightness is + + align:start position:0% +brightness is + + + align:start position:0% +brightness is +you know cosine of the incident angle + + align:start position:0% +you know cosine of the incident angle + + + align:start position:0% +you know cosine of the incident angle +and the cosine doesn't get bigger than + + align:start position:0% +and the cosine doesn't get bigger than + + + align:start position:0% +and the cosine doesn't get bigger than +one + + align:start position:0% +one + + + align:start position:0% +one +and it does so for zero angle so that's + + align:start position:0% +and it does so for zero angle so that's + + + align:start position:0% +and it does so for zero angle so that's +when the surface normal and the + + align:start position:0% +when the surface normal and the + + + align:start position:0% +when the surface normal and the +direction to the light source are the + + align:start position:0% +direction to the light source are the + + + align:start position:0% +direction to the light source are the +same + + align:start position:0% + + + + align:start position:0% + +so that's kind of a special thing + + align:start position:0% +so that's kind of a special thing + + + align:start position:0% +so that's kind of a special thing +and so unique i mean it doesn't happen + + align:start position:0% +and so unique i mean it doesn't happen + + + align:start position:0% +and so unique i mean it doesn't happen +anywhere else so let's see + + align:start position:0% +anywhere else so let's see + + + align:start position:0% +anywhere else so let's see +how to formalize this + + align:start position:0% +how to formalize this + + + align:start position:0% +how to formalize this +unique + + align:start position:0% +unique + + + align:start position:0% +unique +global + + align:start position:0% +global + + + align:start position:0% +global +isolated + + align:start position:0% +isolated + + + align:start position:0% +isolated +extremum + + align:start position:0% + + + + align:start position:0% + +so if i go back to + + align:start position:0% + + + + align:start position:0% + +you know for example inversion surface + + align:start position:0% +you know for example inversion surface + + + align:start position:0% +you know for example inversion surface +i have a reflectance map like this + + align:start position:0% +i have a reflectance map like this + + + align:start position:0% +i have a reflectance map like this +and here is my unique global isolated + + align:start position:0% +and here is my unique global isolated + + + align:start position:0% +and here is my unique global isolated +extremum + + align:start position:0% + + + + align:start position:0% + +right so most brightness measurements + + align:start position:0% +right so most brightness measurements + + + align:start position:0% +right so most brightness measurements +uh + + align:start position:0% +uh + + + align:start position:0% +uh +don't tell me the orientation that you + + align:start position:0% +don't tell me the orientation that you + + + align:start position:0% +don't tell me the orientation that you +know if i measure this brightness well + + align:start position:0% +know if i measure this brightness well + + + align:start position:0% +know if i measure this brightness well +it could be any one of those + + align:start position:0% +it could be any one of those + + + align:start position:0% +it could be any one of those +if i measure this brightness it could be + + align:start position:0% +if i measure this brightness it could be + + + align:start position:0% +if i measure this brightness it could be +any one of those + + align:start position:0% + + + + align:start position:0% + +but if i measure that brightness + + align:start position:0% +but if i measure that brightness + + + align:start position:0% +but if i measure that brightness +i have i have the surface orientation so + + align:start position:0% +i have i have the surface orientation so + + + align:start position:0% +i have i have the surface orientation so +that's very special and these things are + + align:start position:0% +that's very special and these things are + + + align:start position:0% +that's very special and these things are +called stationary points + + align:start position:0% + + + + align:start position:0% + +and why that well because + + align:start position:0% +and why that well because + + + align:start position:0% +and why that well because +places where the derivative is zero in + + align:start position:0% +places where the derivative is zero in + + + align:start position:0% +places where the derivative is zero in +the + + align:start position:0% + + + + align:start position:0% + +reflectance map and we'll see there's + + align:start position:0% +reflectance map and we'll see there's + + + align:start position:0% +reflectance map and we'll see there's +another reason for calling them + + align:start position:0% +another reason for calling them + + + align:start position:0% +another reason for calling them +stationary points so maybe we can start + + align:start position:0% +stationary points so maybe we can start + + + align:start position:0% +stationary points so maybe we can start +the solution there + + align:start position:0% +the solution there + + + align:start position:0% +the solution there +and get rid of this problem about + + align:start position:0% +and get rid of this problem about + + + align:start position:0% +and get rid of this problem about +needing + + align:start position:0% +needing + + + align:start position:0% +needing +an initial curve + + align:start position:0% + + + + align:start position:0% + +well + + align:start position:0% +well + + + align:start position:0% +well +if it's an extremum + + align:start position:0% +if it's an extremum + + + align:start position:0% +if it's an extremum +that means that uh r sub p + + align:start position:0% +that means that uh r sub p + + + align:start position:0% +that means that uh r sub p +and r sub q are zero + + align:start position:0% +and r sub q are zero + + + align:start position:0% +and r sub q are zero +well + + align:start position:0% +well + + + align:start position:0% +well +if it's smooth and and uh + + align:start position:0% +if it's smooth and and uh + + + align:start position:0% +if it's smooth and and uh +an extreme + + align:start position:0% +an extreme + + + align:start position:0% +an extreme +and um + + align:start position:0% +and um + + + align:start position:0% +and um +we could we could consider the case + + align:start position:0% +we could we could consider the case + + + align:start position:0% +we could we could consider the case +where + + align:start position:0% +where + + + align:start position:0% +where +we have some sort of + + align:start position:0% +we have some sort of + + + align:start position:0% +we have some sort of +non-differentiable + + align:start position:0% +non-differentiable + + + align:start position:0% +non-differentiable +r of p and q but + + align:start position:0% +r of p and q but + + + align:start position:0% +r of p and q but +let's let's not do that let's uh + + align:start position:0% +let's let's not do that let's uh + + + align:start position:0% +let's let's not do that let's uh +stay real + + align:start position:0% +stay real + + + align:start position:0% +stay real +okay + + align:start position:0% +okay + + + align:start position:0% +okay +fine + + align:start position:0% +fine + + + align:start position:0% +fine +what's the problem with that well the + + align:start position:0% +what's the problem with that well the + + + align:start position:0% +what's the problem with that well the +problem with that is that + + align:start position:0% +problem with that is that + + + align:start position:0% +problem with that is that +our five differential equations + + align:start position:0% +our five differential equations + + + align:start position:0% +our five differential equations +included + + align:start position:0% + + + + align:start position:0% + +these two + + align:start position:0% + + + + align:start position:0% + +right so + + align:start position:0% +right so + + + align:start position:0% +right so +um + + align:start position:0% +um + + + align:start position:0% +um +at this particular point suppose i put + + align:start position:0% +at this particular point suppose i put + + + align:start position:0% +at this particular point suppose i put +my solution my solver down at that point + + align:start position:0% +my solution my solver down at that point + + + align:start position:0% +my solution my solver down at that point +in the image + + align:start position:0% +in the image + + + align:start position:0% +in the image +corresponding point in the image + + align:start position:0% +corresponding point in the image + + + align:start position:0% +corresponding point in the image +it's not going to go anywhere + + align:start position:0% +it's not going to go anywhere + + + align:start position:0% +it's not going to go anywhere +because you know + + align:start position:0% +because you know + + + align:start position:0% +because you know +r sub p and r sub q are zero + + align:start position:0% +r sub p and r sub q are zero + + + align:start position:0% +r sub p and r sub q are zero +and actually + + align:start position:0% + + + + align:start position:0% + +also + + align:start position:0% +also + + + align:start position:0% +also +if we + + align:start position:0% +if we + + + align:start position:0% +if we +consider the image itself so that's the + + align:start position:0% +consider the image itself so that's the + + + align:start position:0% +consider the image itself so that's the +reflectance map + + align:start position:0% +reflectance map + + + align:start position:0% +reflectance map +and here's the image itself + + align:start position:0% +and here's the image itself + + + align:start position:0% +and here's the image itself +well + + align:start position:0% +well + + + align:start position:0% +well +corresponding to that point in the + + align:start position:0% +corresponding to that point in the + + + align:start position:0% +corresponding to that point in the +reflectance map you know i suppose + + align:start position:0% +reflectance map you know i suppose + + + align:start position:0% +reflectance map you know i suppose +here's my beach ball + + align:start position:0% + + + + align:start position:0% + +you know there's there's this point + + align:start position:0% +you know there's there's this point + + + align:start position:0% +you know there's there's this point +um + + align:start position:0% +um + + + align:start position:0% +um +well that's an extremum in the image and + + align:start position:0% +well that's an extremum in the image and + + + align:start position:0% +well that's an extremum in the image and +so here + + align:start position:0% + + + + align:start position:0% + +by the same argument if it's you know if + + align:start position:0% +by the same argument if it's you know if + + + align:start position:0% +by the same argument if it's you know if +e of x and y is smooth and uh it's + + align:start position:0% +e of x and y is smooth and uh it's + + + align:start position:0% +e of x and y is smooth and uh it's +that's supposed to be uh + + align:start position:0% +that's supposed to be uh + + + align:start position:0% +that's supposed to be uh +extremum then the derivatives there will + + align:start position:0% +extremum then the derivatives there will + + + align:start position:0% +extremum then the derivatives there will +be zero and so what does that mean well + + align:start position:0% +be zero and so what does that mean well + + + align:start position:0% +be zero and so what does that mean well +that means that uh dpd + + align:start position:0% +that means that uh dpd + + + align:start position:0% +that means that uh dpd +that these also don't change + + align:start position:0% + + + + align:start position:0% + +right and since z is dependent on those + + align:start position:0% +right and since z is dependent on those + + + align:start position:0% +right and since z is dependent on those +and nothing changes we're just stuck at + + align:start position:0% +and nothing changes we're just stuck at + + + align:start position:0% +and nothing changes we're just stuck at +that point i mean it would have been + + align:start position:0% +that point i mean it would have been + + + align:start position:0% +that point i mean it would have been +perhaps that well you're at that point + + align:start position:0% +perhaps that well you're at that point + + + align:start position:0% +perhaps that well you're at that point +but p and q change and after a while + + align:start position:0% +but p and q change and after a while + + + align:start position:0% +but p and q change and after a while +there'll be a change in x and y but no + + align:start position:0% +there'll be a change in x and y but no + + + align:start position:0% +there'll be a change in x and y but no +that doesn't work that way everything is + + align:start position:0% +that doesn't work that way everything is + + + align:start position:0% +that doesn't work that way everything is +is zero there + + align:start position:0% +is zero there + + + align:start position:0% +is zero there +so + + align:start position:0% +so + + + align:start position:0% +so +stationary points are + + align:start position:0% +stationary points are + + + align:start position:0% +stationary points are +very interesting because they give us + + align:start position:0% +very interesting because they give us + + + align:start position:0% +very interesting because they give us +local information about surface + + align:start position:0% +local information about surface + + + align:start position:0% +local information about surface +orientation but they don't sort of + + align:start position:0% +orientation but they don't sort of + + + align:start position:0% +orientation but they don't sort of +directly allow us to start start the + + align:start position:0% +directly allow us to start start the + + + align:start position:0% +directly allow us to start start the +solution + + align:start position:0% +solution + + + align:start position:0% +solution +we can go on with this i said extremum + + align:start position:0% +we can go on with this i said extremum + + + align:start position:0% +we can go on with this i said extremum +rather than maximum + + align:start position:0% +rather than maximum + + + align:start position:0% +rather than maximum +because for lambertian it's a maximum + + align:start position:0% +because for lambertian it's a maximum + + + align:start position:0% +because for lambertian it's a maximum +but for the scanning electron microscope + + align:start position:0% +but for the scanning electron microscope + + + align:start position:0% +but for the scanning electron microscope +it's not it's it's a minimum right for + + align:start position:0% +it's not it's it's a minimum right for + + + align:start position:0% +it's not it's it's a minimum right for +the scanning electron microscope we had + + align:start position:0% +the scanning electron microscope we had + + + align:start position:0% +the scanning electron microscope we had +reflectance map that looked like this + + align:start position:0% +reflectance map that looked like this + + + align:start position:0% +reflectance map that looked like this +and this this was the magic point and + + align:start position:0% +and this this was the magic point and + + + align:start position:0% +and this this was the magic point and +there uh the brightness is minimum + + align:start position:0% +there uh the brightness is minimum + + + align:start position:0% +there uh the brightness is minimum +right remember the objects were the + + align:start position:0% +right remember the objects were the + + + align:start position:0% +right remember the objects were the +edges the occluding boundaries were + + align:start position:0% +edges the occluding boundaries were + + + align:start position:0% +edges the occluding boundaries were +bright in the image + + align:start position:0% +bright in the image + + + align:start position:0% +bright in the image +and the + + align:start position:0% +and the + + + align:start position:0% +and the +part facing you was dark so in the case + + align:start position:0% +part facing you was dark so in the case + + + align:start position:0% +part facing you was dark so in the case +of a scanning electron microscope we do + + align:start position:0% +of a scanning electron microscope we do + + + align:start position:0% +of a scanning electron microscope we do +also have stationary points but they + + align:start position:0% +also have stationary points but they + + + align:start position:0% +also have stationary points but they +correspond to + + align:start position:0% +correspond to + + + align:start position:0% +correspond to +minima rather than maxima but anyway + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +so what to do well + + align:start position:0% +so what to do well + + + align:start position:0% +so what to do well +if we can get away + + align:start position:0% +if we can get away + + + align:start position:0% +if we can get away +if we can get a little bit away from + + align:start position:0% +if we can get a little bit away from + + + align:start position:0% +if we can get a little bit away from +this point + + align:start position:0% +this point + + + align:start position:0% +this point +then those conditions aren't + + align:start position:0% +then those conditions aren't + + + align:start position:0% +then those conditions aren't +going to be true anymore and those + + align:start position:0% +going to be true anymore and those + + + align:start position:0% +going to be true anymore and those +quantities may be small but at least we + + align:start position:0% +quantities may be small but at least we + + + align:start position:0% +quantities may be small but at least we +can move and of course we can control + + align:start position:0% +can move and of course we can control + + + align:start position:0% +can move and of course we can control +the speed so suppose the quantities are + + align:start position:0% +the speed so suppose the quantities are + + + align:start position:0% +the speed so suppose the quantities are +small big deal we just multiply the step + + align:start position:0% +small big deal we just multiply the step + + + align:start position:0% +small big deal we just multiply the step +size so so as long as we can get away + + align:start position:0% +size so so as long as we can get away + + + align:start position:0% +size so so as long as we can get away +from that point but + + align:start position:0% +from that point but + + + align:start position:0% +from that point but +you know how do we get away so here's + + align:start position:0% +you know how do we get away so here's + + + align:start position:0% +you know how do we get away so here's +our + + align:start position:0% +our + + + align:start position:0% +our +stationary point and one thing we can + + align:start position:0% +stationary point and one thing we can + + + align:start position:0% +stationary point and one thing we can +think of doing is + + align:start position:0% +think of doing is + + + align:start position:0% +think of doing is +sort of + + align:start position:0% +sort of + + + align:start position:0% +sort of +constructing a + + align:start position:0% +constructing a + + + align:start position:0% +constructing a +approximation of the surface + + align:start position:0% +approximation of the surface + + + align:start position:0% +approximation of the surface +let's suppose + + align:start position:0% + + + + align:start position:0% + +okay so here's the story we know + + align:start position:0% +okay so here's the story we know + + + align:start position:0% +okay so here's the story we know +uh we know the surface orientation there + + align:start position:0% +uh we know the surface orientation there + + + align:start position:0% +uh we know the surface orientation there +because it's one of those stationary + + align:start position:0% +because it's one of those stationary + + + align:start position:0% +because it's one of those stationary +points + + align:start position:0% +points + + + align:start position:0% +points +and now we want to get away from it a + + align:start position:0% +and now we want to get away from it a + + + align:start position:0% +and now we want to get away from it a +little bit so we can start the solution + + align:start position:0% +little bit so we can start the solution + + + align:start position:0% +little bit so we can start the solution +so the idea is we want to start the + + align:start position:0% +so the idea is we want to start the + + + align:start position:0% +so the idea is we want to start the +solution from from this curve + + align:start position:0% +solution from from this curve + + + align:start position:0% +solution from from this curve +so we know the orientation so we can + + align:start position:0% +so we know the orientation so we can + + + align:start position:0% +so we know the orientation so we can +construct a small plane + + align:start position:0% +construct a small plane + + + align:start position:0% +construct a small plane +and you know i don't know make a radius + + align:start position:0% +and you know i don't know make a radius + + + align:start position:0% +and you know i don't know make a radius +epsilon + + align:start position:0% +epsilon + + + align:start position:0% +epsilon +and + + align:start position:0% +and + + + align:start position:0% +and +then + + align:start position:0% +then + + + align:start position:0% +then +start the solutions there + + align:start position:0% + + + + align:start position:0% + +is that gonna work + + align:start position:0% + + + + align:start position:0% + +well if it's a plane + + align:start position:0% +well if it's a plane + + + align:start position:0% +well if it's a plane +then all parts of it have the same + + align:start position:0% +then all parts of it have the same + + + align:start position:0% +then all parts of it have the same +orientation they all have the same + + align:start position:0% +orientation they all have the same + + + align:start position:0% +orientation they all have the same +brightness + + align:start position:0% +brightness + + + align:start position:0% +brightness +and we're just exactly the same problem + + align:start position:0% +and we're just exactly the same problem + + + align:start position:0% +and we're just exactly the same problem +out here than we were there + + align:start position:0% +out here than we were there + + + align:start position:0% +out here than we were there +so that + + align:start position:0% +so that + + + align:start position:0% +so that +idea doesn't quite work + + align:start position:0% +idea doesn't quite work + + + align:start position:0% +idea doesn't quite work +so the answer is well let's have a + + align:start position:0% +so the answer is well let's have a + + + align:start position:0% +so the answer is well let's have a +curved surface so we still have that + + align:start position:0% +curved surface so we still have that + + + align:start position:0% +curved surface so we still have that +special point but now let's suppose that + + align:start position:0% +special point but now let's suppose that + + + align:start position:0% +special point but now let's suppose that +the surface is curved and we're going to + + align:start position:0% +the surface is curved and we're going to + + + align:start position:0% +the surface is curved and we're going to +construct + + align:start position:0% +construct + + + align:start position:0% +construct +a + + align:start position:0% +a + + + align:start position:0% +a +small + + align:start position:0% +small + + + align:start position:0% +small +you know curved shape around that point + + align:start position:0% +you know curved shape around that point + + + align:start position:0% +you know curved shape around that point +and we'll start the solution from there + + align:start position:0% + + + + align:start position:0% + +so you know this this sounds + + align:start position:0% +so you know this this sounds + + + align:start position:0% +so you know this this sounds +kind of um i don't know specialized + + align:start position:0% +kind of um i don't know specialized + + + align:start position:0% +kind of um i don't know specialized +weird um + + align:start position:0% +weird um + + + align:start position:0% +weird um +why these points and so on but actually + + align:start position:0% +why these points and so on but actually + + + align:start position:0% +why these points and so on but actually +these points are very important in human + + align:start position:0% +these points are very important in human + + + align:start position:0% +these points are very important in human +perception as well so you know you can + + align:start position:0% +perception as well so you know you can + + + align:start position:0% +perception as well so you know you can +do experiments where you + + align:start position:0% +do experiments where you + + + align:start position:0% +do experiments where you +show someone a picture of a vaz and i + + align:start position:0% +show someone a picture of a vaz and i + + + align:start position:0% +show someone a picture of a vaz and i +have a very good idea of what its shape + + align:start position:0% +have a very good idea of what its shape + + + align:start position:0% +have a very good idea of what its shape +is i mean not metrically accurate but + + align:start position:0% +is i mean not metrically accurate but + + + align:start position:0% +is i mean not metrically accurate but +generally pretty good + + align:start position:0% +generally pretty good + + + align:start position:0% +generally pretty good +and then you + + align:start position:0% +and then you + + + align:start position:0% +and then you +photoshop out the bright spot + + align:start position:0% +photoshop out the bright spot + + + align:start position:0% +photoshop out the bright spot +and + + align:start position:0% +and + + + align:start position:0% +and +they still have a shape in mind but it's + + align:start position:0% +they still have a shape in mind but it's + + + align:start position:0% +they still have a shape in mind but it's +changed and so actually + + align:start position:0% +changed and so actually + + + align:start position:0% +changed and so actually +it turns out that we use + + align:start position:0% +it turns out that we use + + + align:start position:0% +it turns out that we use +these stationary points as well + + align:start position:0% + + + + align:start position:0% + +another example is where you have + + align:start position:0% +another example is where you have + + + align:start position:0% +another example is where you have +cut out + + align:start position:0% +cut out + + + align:start position:0% +cut out +so you have some + + align:start position:0% +so you have some + + + align:start position:0% +so you have some +some blob in the world like like this + + align:start position:0% +some blob in the world like like this + + + align:start position:0% +some blob in the world like like this +but now you're showing someone a picture + + align:start position:0% +but now you're showing someone a picture + + + align:start position:0% +but now you're showing someone a picture +of only i don't know say that + + align:start position:0% +of only i don't know say that + + + align:start position:0% +of only i don't know say that +that doesn't include uh the bright point + + align:start position:0% +that doesn't include uh the bright point + + + align:start position:0% +that doesn't include uh the bright point +it turns out that this is much more + + align:start position:0% +it turns out that this is much more + + + align:start position:0% +it turns out that this is much more +ambiguous that + + align:start position:0% +ambiguous that + + + align:start position:0% +ambiguous that +then if you included that bright point + + align:start position:0% +then if you included that bright point + + + align:start position:0% +then if you included that bright point +so it's + + align:start position:0% +so it's + + + align:start position:0% +so it's +it's a real thing it's not just you know + + align:start position:0% +it's a real thing it's not just you know + + + align:start position:0% +it's a real thing it's not just you know +something that + + align:start position:0% +something that + + + align:start position:0% +something that +affects our particular method of + + align:start position:0% +affects our particular method of + + + align:start position:0% +affects our particular method of +solution it's uh important for there to + + align:start position:0% +solution it's uh important for there to + + + align:start position:0% +solution it's uh important for there to +be a unique solution + + align:start position:0% +be a unique solution + + + align:start position:0% +be a unique solution +or or a small number of solutions as + + align:start position:0% +or or a small number of solutions as + + + align:start position:0% +or or a small number of solutions as +opposed to an infinite number of + + align:start position:0% +opposed to an infinite number of + + + align:start position:0% +opposed to an infinite number of +solutions + + align:start position:0% +solutions + + + align:start position:0% +solutions +okay so um + + align:start position:0% +okay so um + + + align:start position:0% +okay so um +this is going to be some sort of uh + + align:start position:0% +this is going to be some sort of uh + + + align:start position:0% +this is going to be some sort of uh +curved uh surface + + align:start position:0% +curved uh surface + + + align:start position:0% +curved uh surface +and we need to find out + + align:start position:0% +and we need to find out + + + align:start position:0% +and we need to find out +what + + align:start position:0% +what + + + align:start position:0% +what +its curvature is + + align:start position:0% +its curvature is + + + align:start position:0% +its curvature is +in order to construct it right and sort + + align:start position:0% +in order to construct it right and sort + + + align:start position:0% +in order to construct it right and sort +of like oh my god now we not only need + + align:start position:0% +of like oh my god now we not only need + + + align:start position:0% +of like oh my god now we not only need +to guess at the surface but we need to + + align:start position:0% +to guess at the surface but we need to + + + align:start position:0% +to guess at the surface but we need to +know the curvature of the surface + + align:start position:0% +know the curvature of the surface + + + align:start position:0% +know the curvature of the surface +but actually it turns out that's uh + + align:start position:0% +but actually it turns out that's uh + + + align:start position:0% +but actually it turns out that's uh +possible and so let's see um + + align:start position:0% + + + + align:start position:0% + +let's see how that might work + + align:start position:0% + + + + align:start position:0% + +so the idea is that + + align:start position:0% + + + + align:start position:0% + +we are going to + + align:start position:0% +we are going to + + + align:start position:0% +we are going to +have a small patch and i'm going to make + + align:start position:0% +have a small patch and i'm going to make + + + align:start position:0% +have a small patch and i'm going to make +this + + align:start position:0% + + + + align:start position:0% + +as simple as it can be + + align:start position:0% +as simple as it can be + + + align:start position:0% +as simple as it can be +so we're going to assume first of all + + align:start position:0% +so we're going to assume first of all + + + align:start position:0% +so we're going to assume first of all +that we have an sem type of + + align:start position:0% +that we have an sem type of + + + align:start position:0% +that we have an sem type of +reflectance map just to make it really + + align:start position:0% +reflectance map just to make it really + + + align:start position:0% +reflectance map just to make it really +simple + + align:start position:0% +simple + + + align:start position:0% +simple +and then let's suppose we have a surface + + align:start position:0% +and then let's suppose we have a surface + + + align:start position:0% +and then let's suppose we have a surface +like this + + align:start position:0% + + + + align:start position:0% + +and + + align:start position:0% +and + + + align:start position:0% +and +this will have a + + align:start position:0% +this will have a + + + align:start position:0% +this will have a +stationary point at the origin + + align:start position:0% + + + + align:start position:0% + +and let's see so you've got p is dz dx + + align:start position:0% +and let's see so you've got p is dz dx + + + align:start position:0% +and let's see so you've got p is dz dx +is 2x + + align:start position:0% +is 2x + + + align:start position:0% +is 2x +q is dz dy + + align:start position:0% +q is dz dy + + + align:start position:0% +q is dz dy +is 4 + + align:start position:0% +is 4 + + + align:start position:0% +is 4 +y + + align:start position:0% +y + + + align:start position:0% +y +and then the reflectance map gives us p + + align:start position:0% +and then the reflectance map gives us p + + + align:start position:0% +and then the reflectance map gives us p +squared plus q squared is + + align:start position:0% +squared plus q squared is + + + align:start position:0% +squared plus q squared is +4x squared plus 16 + + align:start position:0% +4x squared plus 16 + + + align:start position:0% +4x squared plus 16 +y squared + + align:start position:0% +y squared + + + align:start position:0% +y squared +and by the image irradiance equation + + align:start position:0% +and by the image irradiance equation + + + align:start position:0% +and by the image irradiance equation +that's actually + + align:start position:0% +that's actually + + + align:start position:0% +that's actually +the image + + align:start position:0% +the image + + + align:start position:0% +the image +okay and i'm going to take the gradient + + align:start position:0% +okay and i'm going to take the gradient + + + align:start position:0% +okay and i'm going to take the gradient +of the image + + align:start position:0% +of the image + + + align:start position:0% +of the image +will be 8 x + + align:start position:0% + + + + align:start position:0% + +and not surprisingly the gradient is 0 + + align:start position:0% +and not surprisingly the gradient is 0 + + + align:start position:0% +and not surprisingly the gradient is 0 +at the origin + + align:start position:0% + + + + align:start position:0% + +and that corresponds to it being an + + align:start position:0% +and that corresponds to it being an + + + align:start position:0% +and that corresponds to it being an +extreme so + + align:start position:0% +extreme so + + + align:start position:0% +extreme so +that just confirms that we have in fact + + align:start position:0% +that just confirms that we have in fact + + + align:start position:0% +that just confirms that we have in fact +set it up so that we have an extremum at + + align:start position:0% +set it up so that we have an extremum at + + + align:start position:0% +set it up so that we have an extremum at +the origin + + align:start position:0% +the origin + + + align:start position:0% +the origin +okay now can i use the gradient to + + align:start position:0% +okay now can i use the gradient to + + + align:start position:0% +okay now can i use the gradient to +estimate the shape local local shape + + align:start position:0% +estimate the shape local local shape + + + align:start position:0% +estimate the shape local local shape +well no because the gradient is zero + + align:start position:0% +well no because the gradient is zero + + + align:start position:0% +well no because the gradient is zero +right at the origin + + align:start position:0% +right at the origin + + + align:start position:0% +right at the origin +and so + + align:start position:0% +and so + + + align:start position:0% +and so +let's take the second derivative + + align:start position:0% + + + + align:start position:0% + +so the plan is + + align:start position:0% +so the plan is + + + align:start position:0% +so the plan is +the gradient will be zero so that's + + align:start position:0% +the gradient will be zero so that's + + + align:start position:0% +the gradient will be zero so that's +useless brightness itself we've already + + align:start position:0% +useless brightness itself we've already + + + align:start position:0% +useless brightness itself we've already +used to determine that it's a stationary + + align:start position:0% +used to determine that it's a stationary + + + align:start position:0% +used to determine that it's a stationary +point but if we take the second partial + + align:start position:0% +point but if we take the second partial + + + align:start position:0% +point but if we take the second partial +derivatives of brightness + + align:start position:0% +derivatives of brightness + + + align:start position:0% +derivatives of brightness +we get some information about the shape + + align:start position:0% +we get some information about the shape + + + align:start position:0% +we get some information about the shape +and we're going to try and recover you + + align:start position:0% +and we're going to try and recover you + + + align:start position:0% +and we're going to try and recover you +know the x squared plus 2y squared from + + align:start position:0% +know the x squared plus 2y squared from + + + align:start position:0% +know the x squared plus 2y squared from +this + + align:start position:0% +this + + + align:start position:0% +this +so it might say well how can i measure + + align:start position:0% +so it might say well how can i measure + + + align:start position:0% +so it might say well how can i measure +the second derivative well of course + + align:start position:0% +the second derivative well of course + + + align:start position:0% +the second derivative well of course +let's just apply the first derivative + + align:start position:0% +let's just apply the first derivative + + + align:start position:0% +let's just apply the first derivative +twice and we also already talked about + + align:start position:0% +twice and we also already talked about + + + align:start position:0% +twice and we also already talked about +uh convenient uh + + align:start position:0% +uh convenient uh + + + align:start position:0% +uh convenient uh +computational molecules for doing that + + align:start position:0% +computational molecules for doing that + + + align:start position:0% +computational molecules for doing that +so there's you know one for ex + + align:start position:0% +so there's you know one for ex + + + align:start position:0% +so there's you know one for ex +exxx + + align:start position:0% +exxx + + + align:start position:0% +exxx +so the plan will be + + align:start position:0% +so the plan will be + + + align:start position:0% +so the plan will be +uh we find the stationary points we + + align:start position:0% +uh we find the stationary points we + + + align:start position:0% +uh we find the stationary points we +estimate the local shape by looking at + + align:start position:0% +estimate the local shape by looking at + + + align:start position:0% +estimate the local shape by looking at +the + + align:start position:0% +the + + + align:start position:0% +the +second not the gradient but the gradient + + align:start position:0% +second not the gradient but the gradient + + + align:start position:0% +second not the gradient but the gradient +of the gradient so to speak and + + align:start position:0% +of the gradient so to speak and + + + align:start position:0% +of the gradient so to speak and +construct a small cap of that shape + + align:start position:0% +construct a small cap of that shape + + + align:start position:0% +construct a small cap of that shape +around the stationary point and then + + align:start position:0% +around the stationary point and then + + + align:start position:0% +around the stationary point and then +start the solutions from there + + align:start position:0% +start the solutions from there + + + align:start position:0% +start the solutions from there +but that + + align:start position:0% +but that + + + align:start position:0% +but that +didn't quite get done with that so we'll + + align:start position:0% +didn't quite get done with that so we'll + + + align:start position:0% +didn't quite get done with that so we'll +finish that next time and then as i said + + align:start position:0% +finish that next time and then as i said + + + align:start position:0% +finish that next time and then as i said +then we'll + + align:start position:0% +then we'll + + + align:start position:0% +then we'll +have a real big change of pace and we + + align:start position:0% +have a real big change of pace and we + + + align:start position:0% +have a real big change of pace and we +start talking about some industrial + + align:start position:0% +start talking about some industrial + + + align:start position:0% +start talking about some industrial +machine vision methods + + align:start position:0% +machine vision methods + + + align:start position:0% +machine vision methods +and the patterns that + + align:start position:0% +and the patterns that + + + align:start position:0% +and the patterns that +describe them \ No newline at end of file diff --git a/Xa2jPbURTjQ.txt b/Xa2jPbURTjQ.txt new file mode 100644 index 0000000000000000000000000000000000000000..617e97e538f9e92cd44ef55ca2081daaf5579c10 --- /dev/null +++ b/Xa2jPbURTjQ.txt @@ -0,0 +1,6379 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT OpenCourseWare continue to + + align:start position:0% +will help MIT OpenCourseWare continue to + + + align:start position:0% +will help MIT OpenCourseWare continue to +offer high quality educational resources + + align:start position:0% +offer high quality educational resources + + + align:start position:0% +offer high quality educational resources +for free + + align:start position:0% +for free + + + align:start position:0% +for free +to make a donation or to view additional + + align:start position:0% +to make a donation or to view additional + + + align:start position:0% +to make a donation or to view additional +materials from hundreds of MIT courses + + align:start position:0% +materials from hundreds of MIT courses + + + align:start position:0% +materials from hundreds of MIT courses +visit MIT opencourseware at ocw.mit.edu + + align:start position:0% +visit MIT opencourseware at ocw.mit.edu + + + align:start position:0% +visit MIT opencourseware at ocw.mit.edu +so we're really moving along this review + + align:start position:0% +so we're really moving along this review + + + align:start position:0% +so we're really moving along this review +of highlights of linear algebra and + + align:start position:0% +of highlights of linear algebra and + + + align:start position:0% +of highlights of linear algebra and +today it's matrices Q they get that name + + align:start position:0% +today it's matrices Q they get that name + + + align:start position:0% +today it's matrices Q they get that name +there they have orthonormal columns so + + align:start position:0% +there they have orthonormal columns so + + + align:start position:0% +there they have orthonormal columns so +that's what one looks like and then the + + align:start position:0% +that's what one looks like and then the + + + align:start position:0% +that's what one looks like and then the +key fact orthonormal columns translates + + align:start position:0% +key fact orthonormal columns translates + + + align:start position:0% +key fact orthonormal columns translates +directly into that simple fact that you + + align:start position:0% +directly into that simple fact that you + + + align:start position:0% +directly into that simple fact that you +just keep remembering every time you see + + align:start position:0% +just keep remembering every time you see + + + align:start position:0% +just keep remembering every time you see +Q transpose Q you've got the identity + + align:start position:0% +Q transpose Q you've got the identity + + + align:start position:0% +Q transpose Q you've got the identity +matrix let's just see why so Q transpose + + align:start position:0% +matrix let's just see why so Q transpose + + + align:start position:0% +matrix let's just see why so Q transpose +would be I'll take those columns and + + align:start position:0% +would be I'll take those columns and + + + align:start position:0% +would be I'll take those columns and +make them into rows and then I multiply + + align:start position:0% +make them into rows and then I multiply + + + align:start position:0% +make them into rows and then I multiply +by Q with the columns and what do I get + + align:start position:0% +by Q with the columns and what do I get + + + align:start position:0% +by Q with the columns and what do I get +well hopefully I get the identity matrix + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +why because oh yeah the normal part + + align:start position:0% +why because oh yeah the normal part + + + align:start position:0% +why because oh yeah the normal part +tells me that the lengths of each vector + + align:start position:0% +tells me that the lengths of each vector + + + align:start position:0% +tells me that the lengths of each vector +that's the length squared Q transpose Q + + align:start position:0% +that's the length squared Q transpose Q + + + align:start position:0% +that's the length squared Q transpose Q +the length squared is 1 so that gives me + + align:start position:0% +the length squared is 1 so that gives me + + + align:start position:0% +the length squared is 1 so that gives me +the 1 in the identity matrix along the + + align:start position:0% +the 1 in the identity matrix along the + + + align:start position:0% +the 1 in the identity matrix along the +diagonal and then Q transpose times a + + align:start position:0% +diagonal and then Q transpose times a + + + align:start position:0% +diagonal and then Q transpose times a +different Q is 0 that's the ortho part + + align:start position:0% +different Q is 0 that's the ortho part + + + align:start position:0% +different Q is 0 that's the ortho part +so that gives me the zeros so that's a + + align:start position:0% +so that gives me the zeros so that's a + + + align:start position:0% +so that gives me the zeros so that's a +simple identity but it translates from a + + align:start position:0% +simple identity but it translates from a + + + align:start position:0% +simple identity but it translates from a +lot of words into a simple expression + + align:start position:0% +lot of words into a simple expression + + + align:start position:0% +lot of words into a simple expression +now does that mean that in the other + + align:start position:0% +now does that mean that in the other + + + align:start position:0% +now does that mean that in the other +order Q Q transpose is that the identity + + align:start position:0% +order Q Q transpose is that the identity + + + align:start position:0% +order Q Q transpose is that the identity +that's so that's a question to think + + align:start position:0% +that's so that's a question to think + + + align:start position:0% +that's so that's a question to think +about is QQ transpose equal the identity + + align:start position:0% +about is QQ transpose equal the identity + + + align:start position:0% +about is QQ transpose equal the identity +question + + align:start position:0% +question + + + align:start position:0% +question +sometimes yes sometimes no easy to tell + + align:start position:0% +sometimes yes sometimes no easy to tell + + + align:start position:0% +sometimes yes sometimes no easy to tell +which the answer is yes yes when Q is + + align:start position:0% +which the answer is yes yes when Q is + + + align:start position:0% +which the answer is yes yes when Q is +square the answer is yes if Q is a + + align:start position:0% +square the answer is yes if Q is a + + + align:start position:0% +square the answer is yes if Q is a +square matrix a square matrix a this is + + align:start position:0% +square matrix a square matrix a this is + + + align:start position:0% +square matrix a square matrix a this is +saying that the square matrix Q has that + + align:start position:0% +saying that the square matrix Q has that + + + align:start position:0% +saying that the square matrix Q has that +inverse on its left but for square + + align:start position:0% +inverse on its left but for square + + + align:start position:0% +inverse on its left but for square +matrices a left inverse Q transpose is + + align:start position:0% +matrices a left inverse Q transpose is + + + align:start position:0% +matrices a left inverse Q transpose is +also a right inverse so for a square + + align:start position:0% +also a right inverse so for a square + + + align:start position:0% +also a right inverse so for a square +matrix if you have an inverse that works + + align:start position:0% +matrix if you have an inverse that works + + + align:start position:0% +matrix if you have an inverse that works +on one side it will work on the other + + align:start position:0% +on one side it will work on the other + + + align:start position:0% +on one side it will work on the other +side so the answer is yes in that case + + align:start position:0% +side so the answer is yes in that case + + + align:start position:0% +side so the answer is yes in that case +and then in that case that's the case + + align:start position:0% +and then in that case that's the case + + + align:start position:0% +and then in that case that's the case +when we call Q is well we really don't + + align:start position:0% +when we call Q is well we really don't + + + align:start position:0% +when we call Q is well we really don't +know what the right name would be but + + align:start position:0% +know what the right name would be but + + + align:start position:0% +know what the right name would be but +here's the name everybody uses an + + align:start position:0% +here's the name everybody uses an + + + align:start position:0% +here's the name everybody uses an +orthogonal matrix and that's that's only + + align:start position:0% +orthogonal matrix and that's that's only + + + align:start position:0% +orthogonal matrix and that's that's only +in their square case square here is an + + align:start position:0% +in their square case square here is an + + + align:start position:0% +in their square case square here is an +orthogonal matrix right right do you - + + align:start position:0% +orthogonal matrix right right do you - + + + align:start position:0% +orthogonal matrix right right do you - +do you want to just see an example of + + align:start position:0% +do you want to just see an example of + + + align:start position:0% +do you want to just see an example of +how that works and it will not so if Q + + align:start position:0% +how that works and it will not so if Q + + + align:start position:0% +how that works and it will not so if Q +is rectangular let's let me do a + + align:start position:0% +is rectangular let's let me do a + + + align:start position:0% +is rectangular let's let me do a +rectangular Q and square Q okay square + + align:start position:0% + + + + align:start position:0% + +all right good to see some orthogonal + + align:start position:0% +all right good to see some orthogonal + + + align:start position:0% +all right good to see some orthogonal +matrices because my message is that + + align:start position:0% +matrices because my message is that + + + align:start position:0% +matrices because my message is that +they're really important in all kinds of + + align:start position:0% +they're really important in all kinds of + + + align:start position:0% +they're really important in all kinds of +applications let's start two-by-two I + + align:start position:0% +applications let's start two-by-two I + + + align:start position:0% +applications let's start two-by-two I +can think of two different ways to get + + align:start position:0% +can think of two different ways to get + + + align:start position:0% +can think of two different ways to get +an orthogonal matrix that's a 2 by 2 + + align:start position:0% +an orthogonal matrix that's a 2 by 2 + + + align:start position:0% +an orthogonal matrix that's a 2 by 2 +matrix and one of them you will know + + align:start position:0% +matrix and one of them you will know + + + align:start position:0% +matrix and one of them you will know +immediately cos theta sine theta so + + align:start position:0% +immediately cos theta sine theta so + + + align:start position:0% +immediately cos theta sine theta so +that's a unit vector it's normalized cos + + align:start position:0% +that's a unit vector it's normalized cos + + + align:start position:0% +that's a unit vector it's normalized cos +squared plus sine squared is 1 and this + + align:start position:0% +squared plus sine squared is 1 and this + + + align:start position:0% +squared plus sine squared is 1 and this +guy has to be orthogonal to it + + align:start position:0% +guy has to be orthogonal to it + + + align:start position:0% +guy has to be orthogonal to it +so I make that - sine theta and cos + + align:start position:0% +so I make that - sine theta and cos + + + align:start position:0% +so I make that - sine theta and cos +theta okay + + align:start position:0% +theta okay + + + align:start position:0% +theta okay +those are both links one they're + + align:start position:0% +those are both links one they're + + + align:start position:0% +those are both links one they're +orthogonal then this is my Q and the + + align:start position:0% +orthogonal then this is my Q and the + + + align:start position:0% +orthogonal then this is my Q and the +inverse of Q will be the transpose if I + + align:start position:0% +inverse of Q will be the transpose if I + + + align:start position:0% +inverse of Q will be the transpose if I +multiply the transpose would put the + + align:start position:0% +multiply the transpose would put the + + + align:start position:0% +multiply the transpose would put the +minus sign down here and would produce + + align:start position:0% +minus sign down here and would produce + + + align:start position:0% +minus sign down here and would produce +the inverse matrix and what is that + + align:start position:0% +the inverse matrix and what is that + + + align:start position:0% +the inverse matrix and what is that +particular matrix represent whoa why do + + align:start position:0% +particular matrix represent whoa why do + + + align:start position:0% +particular matrix represent whoa why do +geometrically why do we where do we see + + align:start position:0% +geometrically why do we where do we see + + + align:start position:0% +geometrically why do we where do we see +that matrix it's a rotation thank you + + align:start position:0% +that matrix it's a rotation thank you + + + align:start position:0% +that matrix it's a rotation thank you +it's a rotation of the whole plane by + + align:start position:0% +it's a rotation of the whole plane by + + + align:start position:0% +it's a rotation of the whole plane by +SATA + + align:start position:0% +SATA + + + align:start position:0% +SATA +yeah so so if I apply that to one zero + + align:start position:0% +yeah so so if I apply that to one zero + + + align:start position:0% +yeah so so if I apply that to one zero +for example I get the first column which + + align:start position:0% +for example I get the first column which + + + align:start position:0% +for example I get the first column which +is cos theta sine theta and that's just + + align:start position:0% +is cos theta sine theta and that's just + + + align:start position:0% +is cos theta sine theta and that's just +a rope let me draw a picture that vector + + align:start position:0% +a rope let me draw a picture that vector + + + align:start position:0% +a rope let me draw a picture that vector +1 0 has got rotated up - so there's the + + align:start position:0% +1 0 has got rotated up - so there's the + + + align:start position:0% +1 0 has got rotated up - so there's the +the 1 0 and there it got rotated through + + align:start position:0% +the 1 0 and there it got rotated through + + + align:start position:0% +the 1 0 and there it got rotated through +an angle theta and similarly 0 1 will + + align:start position:0% +an angle theta and similarly 0 1 will + + + align:start position:0% +an angle theta and similarly 0 1 will +get rotated through an angle theta 2 + + align:start position:0% +get rotated through an angle theta 2 + + + align:start position:0% +get rotated through an angle theta 2 +there so the whole plane rotates oh that + + align:start position:0% +there so the whole plane rotates oh that + + + align:start position:0% +there so the whole plane rotates oh that +makes me remember a highly important + + align:start position:0% +makes me remember a highly important + + + align:start position:0% +makes me remember a highly important +very important property of Q it doesn't + + align:start position:0% +very important property of Q it doesn't + + + align:start position:0% +very important property of Q it doesn't +change length the length of any vector + + align:start position:0% +change length the length of any vector + + + align:start position:0% +change length the length of any vector +is the same after you rotate it the + + align:start position:0% +is the same after you rotate it the + + + align:start position:0% +is the same after you rotate it the +length of any vector is the same after + + align:start position:0% +length of any vector is the same after + + + align:start position:0% +length of any vector is the same after +you multiply by Q can I just do that + + align:start position:0% +you multiply by Q can I just do that + + + align:start position:0% +you multiply by Q can I just do that +I claim any X any vector X I want to + + align:start position:0% +I claim any X any vector X I want to + + + align:start position:0% +I claim any X any vector X I want to +look at the length of Q X and I claim + + align:start position:0% +look at the length of Q X and I claim + + + align:start position:0% +look at the length of Q X and I claim +that it has the same length as X + + align:start position:0% +that it has the same length as X + + + align:start position:0% +that it has the same length as X +actually that's the reason in + + align:start position:0% +actually that's the reason in + + + align:start position:0% +actually that's the reason in +computations that orthogonal matrix are + + align:start position:0% +computations that orthogonal matrix are + + + align:start position:0% +computations that orthogonal matrix are +so much loved because no overflow can + + align:start position:0% +so much loved because no overflow can + + + align:start position:0% +so much loved because no overflow can +happen with orthogonal matrices lengths + + align:start position:0% +happen with orthogonal matrices lengths + + + align:start position:0% +happen with orthogonal matrices lengths +don't change I can multiply by any + + align:start position:0% +don't change I can multiply by any + + + align:start position:0% +don't change I can multiply by any +number of orthogonal matrices and the + + align:start position:0% +number of orthogonal matrices and the + + + align:start position:0% +number of orthogonal matrices and the +lengths don't change can we just see why + + align:start position:0% +lengths don't change can we just see why + + + align:start position:0% +lengths don't change can we just see why +that's true how would you so what do we + + align:start position:0% +that's true how would you so what do we + + + align:start position:0% +that's true how would you so what do we +have to go on we + + align:start position:0% +have to go on we + + + align:start position:0% +have to go on we +what we have to go on is Q transpose Q + + align:start position:0% +what we have to go on is Q transpose Q + + + align:start position:0% +what we have to go on is Q transpose Q +equal I whenever we're gonna prove it's + + align:start position:0% +equal I whenever we're gonna prove it's + + + align:start position:0% +equal I whenever we're gonna prove it's +got to come out of that because that's + + align:start position:0% +got to come out of that because that's + + + align:start position:0% +got to come out of that because that's +all we know so how do I use that to get + + align:start position:0% +all we know so how do I use that to get + + + align:start position:0% +all we know so how do I use that to get +that + + align:start position:0% +that + + + align:start position:0% +that +well we haven't said a whole lot about + + align:start position:0% +well we haven't said a whole lot about + + + align:start position:0% +well we haven't said a whole lot about +lengths but you'll see it all now it'll + + align:start position:0% +lengths but you'll see it all now it'll + + + align:start position:0% +lengths but you'll see it all now it'll +be easier to prove that the squares are + + align:start position:0% +be easier to prove that the squares are + + + align:start position:0% +be easier to prove that the squares are +the same so what's the what's the matrix + + align:start position:0% +the same so what's the what's the matrix + + + align:start position:0% +the same so what's the what's the matrix +expression for the length squared what's + + align:start position:0% +expression for the length squared what's + + + align:start position:0% +expression for the length squared what's +what's the right-hand side of that + + align:start position:0% +what's the right-hand side of that + + + align:start position:0% +what's the right-hand side of that +equation X transpose X right X transpose + + align:start position:0% +equation X transpose X right X transpose + + + align:start position:0% +equation X transpose X right X transpose +X gives me the sum of the squares + + align:start position:0% +X gives me the sum of the squares + + + align:start position:0% +X gives me the sum of the squares +Pythagoras says that's the length + + align:start position:0% +Pythagoras says that's the length + + + align:start position:0% +Pythagoras says that's the length +squared so that right hand side is X + + align:start position:0% +squared so that right hand side is X + + + align:start position:0% +squared so that right hand side is X +transpose X what's the left side + + align:start position:0% +transpose X what's the left side + + + align:start position:0% +transpose X what's the left side +it's a length squared of this of QX so + + align:start position:0% +it's a length squared of this of QX so + + + align:start position:0% +it's a length squared of this of QX so +it must be the same as hue X transpose + + align:start position:0% +it must be the same as hue X transpose + + + align:start position:0% +it must be the same as hue X transpose +QX and the claim is that that equation + + align:start position:0% +QX and the claim is that that equation + + + align:start position:0% +QX and the claim is that that equation +holds and do you see it + + align:start position:0% +holds and do you see it + + + align:start position:0% +holds and do you see it +whereís so any property if from Q is + + align:start position:0% +whereís so any property if from Q is + + + align:start position:0% +whereís so any property if from Q is +going to has to just come out directly + + align:start position:0% +going to has to just come out directly + + + align:start position:0% +going to has to just come out directly +from that where is it here do I just + + align:start position:0% +from that where is it here do I just + + + align:start position:0% +from that where is it here do I just +like push away a little bit at that left + + align:start position:0% +like push away a little bit at that left + + + align:start position:0% +like push away a little bit at that left +hand side and see it + + align:start position:0% +hand side and see it + + + align:start position:0% +hand side and see it +QX transpose is the same as X transpose + + align:start position:0% +QX transpose is the same as X transpose + + + align:start position:0% +QX transpose is the same as X transpose +Q transpose and QX is QX and now I'm + + align:start position:0% +Q transpose and QX is QX and now I'm + + + align:start position:0% +Q transpose and QX is QX and now I'm +seeing well you might say wait a minute + + align:start position:0% +seeing well you might say wait a minute + + + align:start position:0% +seeing well you might say wait a minute +the parentheses were there and there but + + align:start position:0% +the parentheses were there and there but + + + align:start position:0% +the parentheses were there and there but +I say the most important law for matrix + + align:start position:0% +I say the most important law for matrix + + + align:start position:0% +I say the most important law for matrix +multiplication is you can move + + align:start position:0% +multiplication is you can move + + + align:start position:0% +multiplication is you can move +parentheses or throw them away let's + + align:start position:0% +parentheses or throw them away let's + + + align:start position:0% +parentheses or throw them away let's +roam away so in here I'm seeing Q + + align:start position:0% +roam away so in here I'm seeing Q + + + align:start position:0% +roam away so in here I'm seeing Q +transpose Q which is the identity so + + align:start position:0% +transpose Q which is the identity so + + + align:start position:0% +transpose Q which is the identity so +it's it's true yeah so that means that + + align:start position:0% +it's it's true yeah so that means that + + + align:start position:0% +it's it's true yeah so that means that +you're never underflow or overflow when + + align:start position:0% +you're never underflow or overflow when + + + align:start position:0% +you're never underflow or overflow when +you're multiplying by Q every numerical + + align:start position:0% +you're multiplying by Q every numerical + + + align:start position:0% +you're multiplying by Q every numerical +algorithm is written to use orthogonal + + align:start position:0% +algorithm is written to use orthogonal + + + align:start position:0% +algorithm is written to use orthogonal +matrices if wherever it can can okay and + + align:start position:0% +matrices if wherever it can can okay and + + + align:start position:0% +matrices if wherever it can can okay and +here's the first example + + align:start position:0% + + + + align:start position:0% + +I think maybe good for me to think of + + align:start position:0% +I think maybe good for me to think of + + + align:start position:0% +I think maybe good for me to think of +other examples or for us to think of + + align:start position:0% +other examples or for us to think of + + + align:start position:0% +other examples or for us to think of +other examples of orthogonal matrices so + + align:start position:0% +other examples of orthogonal matrices so + + + align:start position:0% +other examples of orthogonal matrices so +I'm using that word orthogonal matrix I + + align:start position:0% +I'm using that word orthogonal matrix I + + + align:start position:0% +I'm using that word orthogonal matrix I +should it really should we should really + + align:start position:0% +should it really should we should really + + + align:start position:0% +should it really should we should really +be saying orthonormal and I'm really + + align:start position:0% +be saying orthonormal and I'm really + + + align:start position:0% +be saying orthonormal and I'm really +thinking mostly of square ones so so the + + align:start position:0% +thinking mostly of square ones so so the + + + align:start position:0% +thinking mostly of square ones so so the +so in the square case when Q transpose + + align:start position:0% +so in the square case when Q transpose + + + align:start position:0% +so in the square case when Q transpose +is Q inverse of course that fact makes + + align:start position:0% +is Q inverse of course that fact makes + + + align:start position:0% +is Q inverse of course that fact makes +it easy to solve all equations that have + + align:start position:0% +it easy to solve all equations that have + + + align:start position:0% +it easy to solve all equations that have +Q as a coefficient matrix because you + + align:start position:0% +Q as a coefficient matrix because you + + + align:start position:0% +Q as a coefficient matrix because you +want the inverse and you just use the + + align:start position:0% +want the inverse and you just use the + + + align:start position:0% +want the inverse and you just use the +transpose okay let's just take a some + + align:start position:0% +transpose okay let's just take a some + + + align:start position:0% +transpose okay let's just take a some +minutes to think of examples of Q's if + + align:start position:0% +minutes to think of examples of Q's if + + + align:start position:0% +minutes to think of examples of Q's if +they're so important there have to be + + align:start position:0% +they're so important there have to be + + + align:start position:0% +they're so important there have to be +interesting examples and that was a + + align:start position:0% +interesting examples and that was a + + + align:start position:0% +interesting examples and that was a +first one now there's one more + + align:start position:0% +first one now there's one more + + + align:start position:0% +first one now there's one more +two-by-two example that I that you + + align:start position:0% +two-by-two example that I that you + + + align:start position:0% +two-by-two example that I that you +should know do you know what that would + + align:start position:0% +should know do you know what that would + + + align:start position:0% +should know do you know what that would +be + + align:start position:0% +be + + + align:start position:0% +be +so another this will be example two and + + align:start position:0% +so another this will be example two and + + + align:start position:0% +so another this will be example two and +it's also going to be only two by two + + align:start position:0% +it's also going to be only two by two + + + align:start position:0% +it's also going to be only two by two +and real and what possibility have I got + + align:start position:0% +and real and what possibility have I got + + + align:start position:0% +and real and what possibility have I got +left here I'll use the same first column + + align:start position:0% +left here I'll use the same first column + + + align:start position:0% +left here I'll use the same first column +cos theta sine theta because that's more + + align:start position:0% +cos theta sine theta because that's more + + + align:start position:0% +cos theta sine theta because that's more +or less any any unit vector in two + + align:start position:0% +or less any any unit vector in two + + + align:start position:0% +or less any any unit vector in two +dimensions this has got that form so + + align:start position:0% +dimensions this has got that form so + + + align:start position:0% +dimensions this has got that form so +what do you propose for the second + + align:start position:0% +what do you propose for the second + + + align:start position:0% +what do you propose for the second +column + + align:start position:0% +column + + + align:start position:0% +column +yes yeah put the put the minus sign down + + align:start position:0% +yes yeah put the put the minus sign down + + + align:start position:0% +yes yeah put the put the minus sign down +here so you think does that make any + + align:start position:0% +here so you think does that make any + + + align:start position:0% +here so you think does that make any +difference so sine theta and minus cos + + align:start position:0% +difference so sine theta and minus cos + + + align:start position:0% +difference so sine theta and minus cos +theta I don't know if you've ever looked + + align:start position:0% +theta I don't know if you've ever looked + + + align:start position:0% +theta I don't know if you've ever looked +at that matrix you know we're trying to + + align:start position:0% +at that matrix you know we're trying to + + + align:start position:0% +at that matrix you know we're trying to +collect together a few matrices that are + + align:start position:0% +collect together a few matrices that are + + + align:start position:0% +collect together a few matrices that are +worth knowing are worth looking at okay + + align:start position:0% +worth knowing are worth looking at okay + + + align:start position:0% +worth knowing are worth looking at okay +now what kind of what's happened here + + align:start position:0% +now what kind of what's happened here + + + align:start position:0% +now what kind of what's happened here +you may say that was a trivial change + + align:start position:0% +you may say that was a trivial change + + + align:start position:0% +you may say that was a trivial change +which it kind of was but it's a + + align:start position:0% +which it kind of was but it's a + + + align:start position:0% +which it kind of was but it's a +different matrix now it's not a rotation + + align:start position:0% +different matrix now it's not a rotation + + + align:start position:0% +different matrix now it's not a rotation +anymore + + align:start position:0% +anymore + + + align:start position:0% +anymore +that's not a rote + + align:start position:0% +that's not a rote + + + align:start position:0% +that's not a rote +and yeah somehow now it's symmetric and + + align:start position:0% +and yeah somehow now it's symmetric and + + + align:start position:0% +and yeah somehow now it's symmetric and +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +yeah what its eigenvectors must be + + align:start position:0% +yeah what its eigenvectors must be + + + align:start position:0% +yeah what its eigenvectors must be +something or other we'll get to those + + align:start position:0% +something or other we'll get to those + + + align:start position:0% +something or other we'll get to those +but what did what does that matrix do I + + align:start position:0% +but what did what does that matrix do I + + + align:start position:0% +but what did what does that matrix do I +don't know I don't know if you've seen + + align:start position:0% +don't know I don't know if you've seen + + + align:start position:0% +don't know I don't know if you've seen +it if you haven't it's not it doesn't + + align:start position:0% +it if you haven't it's not it doesn't + + + align:start position:0% +it if you haven't it's not it doesn't +jump out but it's a important case this + + align:start position:0% +jump out but it's a important case this + + + align:start position:0% +jump out but it's a important case this +is a reflection matrix notice that it's + + align:start position:0% +is a reflection matrix notice that it's + + + align:start position:0% +is a reflection matrix notice that it's +determined it is minus 1 you have minus + + align:start position:0% +determined it is minus 1 you have minus + + + align:start position:0% +determined it is minus 1 you have minus +cos squared theta minus sine squared + + align:start position:0% +cos squared theta minus sine squared + + + align:start position:0% +cos squared theta minus sine squared +theta it's determinate is minus 1 + + align:start position:0% +theta it's determinate is minus 1 + + + align:start position:0% +theta it's determinate is minus 1 +there's some some some eigenvalue it + + align:start position:0% +there's some some some eigenvalue it + + + align:start position:0% +there's some some some eigenvalue it +coming up with that that's got a - yeah + + align:start position:0% +coming up with that that's got a - yeah + + + align:start position:0% +coming up with that that's got a - yeah +ok so what do I mean by a reflection + + align:start position:0% +ok so what do I mean by a reflection + + + align:start position:0% +ok so what do I mean by a reflection +matrix let me draw the plane and I think + + align:start position:0% +matrix let me draw the plane and I think + + + align:start position:0% +matrix let me draw the plane and I think +so so 1 0 let's follow it follow again 1 + + align:start position:0% +so so 1 0 let's follow it follow again 1 + + + align:start position:0% +so so 1 0 let's follow it follow again 1 +0 where does that go + + align:start position:0% +0 where does that go + + + align:start position:0% +0 where does that go +that gives me the first column so as + + align:start position:0% +that gives me the first column so as + + + align:start position:0% +that gives me the first column so as +before it goes to cos theta sine theta + + align:start position:0% + + + + align:start position:0% + +and when I say reflection let me put put + + align:start position:0% +and when I say reflection let me put put + + + align:start position:0% +and when I say reflection let me put put +the the mirror into the picture so you + + align:start position:0% +the the mirror into the picture so you + + + align:start position:0% +the the mirror into the picture so you +see what reflection it is the mirror is + + align:start position:0% +see what reflection it is the mirror is + + + align:start position:0% +see what reflection it is the mirror is +is along here at angle fate / - stayed + + align:start position:0% +is along here at angle fate / - stayed + + + align:start position:0% +is along here at angle fate / - stayed +over to live so sure enough 1 0 at angle + + align:start position:0% +over to live so sure enough 1 0 at angle + + + align:start position:0% +over to live so sure enough 1 0 at angle +0 got reflected into a unit vector at + + align:start position:0% +0 got reflected into a unit vector at + + + align:start position:0% +0 got reflected into a unit vector at +angle theta and halfway between was the + + align:start position:0% +angle theta and halfway between was the + + + align:start position:0% +angle theta and halfway between was the +saito virtu line that's that's not + + align:start position:0% +saito virtu line that's that's not + + + align:start position:0% +saito virtu line that's that's not +that's okay now what about the other guy + + align:start position:0% +that's okay now what about the other guy + + + align:start position:0% +that's okay now what about the other guy +0 1 + + align:start position:0% +0 1 + + + align:start position:0% +0 1 +here's 0 1 ok I multiply that can I put + + align:start position:0% +here's 0 1 ok I multiply that can I put + + + align:start position:0% +here's 0 1 ok I multiply that can I put +the 0 1 up here so you just your eye + + align:start position:0% +the 0 1 up here so you just your eye + + + align:start position:0% +the 0 1 up here so you just your eye +does the multiplication where is the + + align:start position:0% +does the multiplication where is the + + + align:start position:0% +does the multiplication where is the +result of 0 1 what's the output from + + align:start position:0% +result of 0 1 what's the output from + + + align:start position:0% +result of 0 1 what's the output from +from cue applied to zero one sine theta + + align:start position:0% +from cue applied to zero one sine theta + + + align:start position:0% +from cue applied to zero one sine theta +minus cos theta right it's the it's the + + align:start position:0% +minus cos theta right it's the it's the + + + align:start position:0% +minus cos theta right it's the it's the +second column and so where is that + + align:start position:0% +second column and so where is that + + + align:start position:0% +second column and so where is that +well it's perpendicular to that guy + + align:start position:0% +well it's perpendicular to that guy + + + align:start position:0% +well it's perpendicular to that guy +that's right I know right that was the + + align:start position:0% +that's right I know right that was the + + + align:start position:0% +that's right I know right that was the +point that the two columns are + + align:start position:0% +point that the two columns are + + + align:start position:0% +point that the two columns are +perpendicular so it's so it must go down + + align:start position:0% +perpendicular so it's so it must go down + + + align:start position:0% +perpendicular so it's so it must go down +this way right sine theta cos theta and + + align:start position:0% +this way right sine theta cos theta and + + + align:start position:0% +this way right sine theta cos theta and +it doesn't change lengths all these + + align:start position:0% +it doesn't change lengths all these + + + align:start position:0% +it doesn't change lengths all these +facts that we just learned are key so + + align:start position:0% +facts that we just learned are key so + + + align:start position:0% +facts that we just learned are key so +there's there's zero one and it goes to + + align:start position:0% +there's there's zero one and it goes to + + + align:start position:0% +there's there's zero one and it goes to +this guy which is whatever that second + + align:start position:0% +this guy which is whatever that second + + + align:start position:0% +this guy which is whatever that second +column is sine theta minus cos theta and + + align:start position:0% +column is sine theta minus cos theta and + + + align:start position:0% +column is sine theta minus cos theta and +if you check that actually like plain + + align:start position:0% +if you check that actually like plain + + + align:start position:0% +if you check that actually like plain +geometry I believe never occurred to me + + align:start position:0% +geometry I believe never occurred to me + + + align:start position:0% +geometry I believe never occurred to me +before but I believe it that that this + + align:start position:0% +before but I believe it that that this + + + align:start position:0% +before but I believe it that that this +angle going down to there that that goes + + align:start position:0% +angle going down to there that that goes + + + align:start position:0% +angle going down to there that that goes +straight through and that the halfway + + align:start position:0% +straight through and that the halfway + + + align:start position:0% +straight through and that the halfway +one is that line yeah I think that + + align:start position:0% +one is that line yeah I think that + + + align:start position:0% +one is that line yeah I think that +picture is got it and I think it's in + + align:start position:0% +picture is got it and I think it's in + + + align:start position:0% +picture is got it and I think it's in +the note so that's a reflection matrix + + align:start position:0% +the note so that's a reflection matrix + + + align:start position:0% +the note so that's a reflection matrix +well that's a two-by-two reflection + + align:start position:0% +well that's a two-by-two reflection + + + align:start position:0% +well that's a two-by-two reflection +matrix would you like to see some other + + align:start position:0% +matrix would you like to see some other + + + align:start position:0% +matrix would you like to see some other +matrices like this one but but larger + + align:start position:0% +matrices like this one but but larger + + + align:start position:0% +matrices like this one but but larger +they're named after a guy named + + align:start position:0% +they're named after a guy named + + + align:start position:0% +they're named after a guy named +householder so these are householder + + align:start position:0% +householder so these are householder + + + align:start position:0% +householder so these are householder +reflections what am I doing here I'm + + align:start position:0% +reflections what am I doing here I'm + + + align:start position:0% +reflections what am I doing here I'm +collecting together some orthogonal + + align:start position:0% +collecting together some orthogonal + + + align:start position:0% +collecting together some orthogonal +matrices that are useful and important + + align:start position:0% +matrices that are useful and important + + + align:start position:0% +matrices that are useful and important +and householder found a whole bunch of + + align:start position:0% +and householder found a whole bunch of + + + align:start position:0% +and householder found a whole bunch of +them and and his algorithm is a much + + align:start position:0% +them and and his algorithm is a much + + + align:start position:0% +them and and his algorithm is a much +used part of numerical linear algebra so + + align:start position:0% +used part of numerical linear algebra so + + + align:start position:0% +used part of numerical linear algebra so +he started with a unit vector start with + + align:start position:0% +he started with a unit vector start with + + + align:start position:0% +he started with a unit vector start with +a unit vector + + align:start position:0% +a unit vector + + + align:start position:0% +a unit vector +you transpose u equal 1 so the length of + + align:start position:0% +you transpose u equal 1 so the length of + + + align:start position:0% +you transpose u equal 1 so the length of +the vector is 1 and then he created + + align:start position:0% +the vector is 1 and then he created + + + align:start position:0% +the vector is 1 and then he created +let's name it after him H he created + + align:start position:0% +let's name it after him H he created + + + align:start position:0% +let's name it after him H he created +this matrix the identity minus 2 uu + + align:start position:0% +this matrix the identity minus 2 uu + + + align:start position:0% +this matrix the identity minus 2 uu +transpose and I believe that that's a + + align:start position:0% +transpose and I believe that that's a + + + align:start position:0% +transpose and I believe that that's a +really useful matrix so it's just like I + + align:start position:0% +really useful matrix so it's just like I + + + align:start position:0% +really useful matrix so it's just like I +think this review is like going beyond + + align:start position:0% +think this review is like going beyond + + + align:start position:0% +think this review is like going beyond +1806 into what is what ones are really + + align:start position:0% +1806 into what is what ones are really + + + align:start position:0% +1806 into what is what ones are really +worth knowing that worth knowing + + align:start position:0% +worth knowing that worth knowing + + + align:start position:0% +worth knowing that worth knowing +individually ok could we just check what + + align:start position:0% +individually ok could we just check what + + + align:start position:0% +individually ok could we just check what +are the properties of house holders + + align:start position:0% +are the properties of house holders + + + align:start position:0% +are the properties of house holders +reflection of that I - to you you + + align:start position:0% +reflection of that I - to you you + + + align:start position:0% +reflection of that I - to you you +recognize here column times a row so + + align:start position:0% +recognize here column times a row so + + + align:start position:0% +recognize here column times a row so +that's a matrix and what kind of what + + align:start position:0% +that's a matrix and what kind of what + + + align:start position:0% +that's a matrix and what kind of what +could you tell me about that matrix u u + + align:start position:0% +could you tell me about that matrix u u + + + align:start position:0% +could you tell me about that matrix u u +transpose it's yeah so uh or what what + + align:start position:0% +transpose it's yeah so uh or what what + + + align:start position:0% +transpose it's yeah so uh or what what +can we say about about about H so I + + align:start position:0% +can we say about about about H so I + + + align:start position:0% +can we say about about about H so I +guess I'm believing that H is a + + align:start position:0% +guess I'm believing that H is a + + + align:start position:0% +guess I'm believing that H is a +orthogonal matrix otherwise it wouldn't + + align:start position:0% +orthogonal matrix otherwise it wouldn't + + + align:start position:0% +orthogonal matrix otherwise it wouldn't +be here today + + align:start position:0% +be here today + + + align:start position:0% +be here today +so I believe that and that not only is + + align:start position:0% +so I believe that and that not only is + + + align:start position:0% +so I believe that and that not only is +it orthogonal it is also have a look at + + align:start position:0% +it orthogonal it is also have a look at + + + align:start position:0% +it orthogonal it is also have a look at +it symmetric it's also symmetric the + + align:start position:0% +it symmetric it's also symmetric the + + + align:start position:0% +it symmetric it's also symmetric the +identity symmetric uu transpose is + + align:start position:0% +identity symmetric uu transpose is + + + align:start position:0% +identity symmetric uu transpose is +symmetric so that this is a family of + + align:start position:0% +symmetric so that this is a family of + + + align:start position:0% +symmetric so that this is a family of +symmetric orthogonal matrices and that + + align:start position:0% +symmetric orthogonal matrices and that + + + align:start position:0% +symmetric orthogonal matrices and that +was one of them that's a symmetric + + align:start position:0% +was one of them that's a symmetric + + + align:start position:0% +was one of them that's a symmetric +orthogonal matrix these matrices are + + align:start position:0% +orthogonal matrix these matrices are + + + align:start position:0% +orthogonal matrix these matrices are +really great to have you just like in in + + align:start position:0% +really great to have you just like in in + + + align:start position:0% +really great to have you just like in in +using linear algebra it's you just get a + + align:start position:0% +using linear algebra it's you just get a + + + align:start position:0% +using linear algebra it's you just get a +collection of useful matrices that you + + align:start position:0% +collection of useful matrices that you + + + align:start position:0% +collection of useful matrices that you +can call on and these are definitely one + + align:start position:0% +can call on and these are definitely one + + + align:start position:0% +can call on and these are definitely one +family well it's obviously symmetric + + align:start position:0% +family well it's obviously symmetric + + + align:start position:0% +family well it's obviously symmetric +shall we check that it's orthogonal so + + align:start position:0% +shall we check that it's orthogonal so + + + align:start position:0% +shall we check that it's orthogonal so +to check that it's orthogonal I just so + + align:start position:0% +to check that it's orthogonal I just so + + + align:start position:0% +to check that it's orthogonal I just so +I'm going to check that H transpose H is + + align:start position:0% +I'm going to check that H transpose H is + + + align:start position:0% +I'm going to check that H transpose H is +the identity can I just check that + + align:start position:0% +the identity can I just check that + + + align:start position:0% +the identity can I just check that +well H transpose is the same as H + + align:start position:0% +well H transpose is the same as H + + + align:start position:0% +well H transpose is the same as H +because it was symmetric so I'm gonna + + align:start position:0% +because it was symmetric so I'm gonna + + + align:start position:0% +because it was symmetric so I'm gonna +square this guy this is really H times H + + align:start position:0% +square this guy this is really H times H + + + align:start position:0% +square this guy this is really H times H +I'm squaring it and what do I get if I + + align:start position:0% +I'm squaring it and what do I get if I + + + align:start position:0% +I'm squaring it and what do I get if I +square so so I get I hope I get the + + align:start position:0% +square so so I get I hope I get the + + + align:start position:0% +square so so I get I hope I get the +identity but let's see it what do I get + + align:start position:0% +identity but let's see it what do I get + + + align:start position:0% +identity but let's see it what do I get +when I Square this get little multiply + + align:start position:0% +when I Square this get little multiply + + + align:start position:0% +when I Square this get little multiply +it out + + align:start position:0% +it out + + + align:start position:0% +it out +so I times I is I and then I get some + + align:start position:0% +so I times I is I and then I get some + + + align:start position:0% +so I times I is I and then I get some +number of uu transpose this how many do + + align:start position:0% +number of uu transpose this how many do + + + align:start position:0% +number of uu transpose this how many do +I get for that from that so I'm squaring + + align:start position:0% +I get for that from that so I'm squaring + + + align:start position:0% +I get for that from that so I'm squaring +this thing because H transpose H is the + + align:start position:0% +this thing because H transpose H is the + + + align:start position:0% +this thing because H transpose H is the +same as H times H so I'm squaring it so + + align:start position:0% +same as H times H so I'm squaring it so + + + align:start position:0% +same as H times H so I'm squaring it so +how many what do I put here for thanks + + align:start position:0% +how many what do I put here for thanks + + + align:start position:0% +how many what do I put here for thanks +and now I've got this guy squared with a + + align:start position:0% +and now I've got this guy squared with a + + + align:start position:0% +and now I've got this guy squared with a +plus so that's four uu transpose uu + + align:start position:0% +plus so that's four uu transpose uu + + + align:start position:0% +plus so that's four uu transpose uu +transpose + + align:start position:0% + + + + align:start position:0% + +yeah I'm totally realizing I've + + align:start position:0% +yeah I'm totally realizing I've + + + align:start position:0% +yeah I'm totally realizing I've +practiced for a lifetime doing these + + align:start position:0% +practiced for a lifetime doing these + + + align:start position:0% +practiced for a lifetime doing these +dinky little calculations but they are + + align:start position:0% +dinky little calculations but they are + + + align:start position:0% +dinky little calculations but they are +dinky and you'll get the hang of it + + align:start position:0% +dinky and you'll get the hang of it + + + align:start position:0% +dinky and you'll get the hang of it +quickly now what am i hoping out of that + + align:start position:0% +quickly now what am i hoping out of that + + + align:start position:0% +quickly now what am i hoping out of that +bottom line that it is I hope you to get + + align:start position:0% +bottom line that it is I hope you to get + + + align:start position:0% +bottom line that it is I hope you to get +I do we get I yes we're who sees how to + + align:start position:0% +I do we get I yes we're who sees how to + + + align:start position:0% +I do we get I yes we're who sees how to +get eye out of that thing yeah u + + align:start position:0% +get eye out of that thing yeah u + + + align:start position:0% +get eye out of that thing yeah u +transpose u in here is a number that was + + align:start position:0% +transpose u in here is a number that was + + + align:start position:0% +transpose u in here is a number that was +you that was column times row times + + align:start position:0% +you that was column times row times + + + align:start position:0% +you that was column times row times +column times row and I look at the in + + align:start position:0% +column times row and I look at the in + + + align:start position:0% +column times row and I look at the in +the middle here is Rho times column and + + align:start position:0% +the middle here is Rho times column and + + + align:start position:0% +the middle here is Rho times column and +that's the number one right because it's + + align:start position:0% +that's the number one right because it's + + + align:start position:0% +that's the number one right because it's +there so that's one and then I have + + align:start position:0% +there so that's one and then I have + + + align:start position:0% +there so that's one and then I have +minus four of that plus four of that + + align:start position:0% +minus four of that plus four of that + + + align:start position:0% +minus four of that plus four of that +they cancel each other and I get I so + + align:start position:0% +they cancel each other and I get I so + + + align:start position:0% +they cancel each other and I get I so +those are good matrices we'll we'll use + + align:start position:0% +those are good matrices we'll we'll use + + + align:start position:0% +those are good matrices we'll we'll use +them we'll use them actually they're + + align:start position:0% +them we'll use them actually they're + + + align:start position:0% +them we'll use them actually they're +better than gram-schmidt so we'll use + + align:start position:0% +better than gram-schmidt so we'll use + + + align:start position:0% +better than gram-schmidt so we'll use +them in in making things orthogonal + + align:start position:0% +them in in making things orthogonal + + + align:start position:0% +them in in making things orthogonal +so what what other orthogonal matrices + + align:start position:0% +so what what other orthogonal matrices + + + align:start position:0% +so what what other orthogonal matrices +let's create some you know creating + + align:start position:0% +let's create some you know creating + + + align:start position:0% +let's create some you know creating +Gordo orthogonal matrices is you know + + align:start position:0% +Gordo orthogonal matrices is you know + + + align:start position:0% +Gordo orthogonal matrices is you know +it's it pays off let's think so there's + + align:start position:0% +it's it pays off let's think so there's + + + align:start position:0% +it's it pays off let's think so there's +a family named after this French guy who + + align:start position:0% +a family named after this French guy who + + + align:start position:0% +a family named after this French guy who +lived to a hundred he was a real old + + align:start position:0% +lived to a hundred he was a real old + + + align:start position:0% +lived to a hundred he was a real old +timer + + align:start position:0% +timer + + + align:start position:0% +timer +well MIT had a faculty member in math + + align:start position:0% +well MIT had a faculty member in math + + + align:start position:0% +well MIT had a faculty member in math +when I came professor strike who lived + + align:start position:0% +when I came professor strike who lived + + + align:start position:0% +when I came professor strike who lived +to a hundred and six and I heard him + + align:start position:0% +to a hundred and six and I heard him + + + align:start position:0% +to a hundred and six and I heard him +give a lecture at Brown University at + + align:start position:0% +give a lecture at Brown University at + + + align:start position:0% +give a lecture at Brown University at +age 100 and it was like perfect you + + align:start position:0% +age 100 and it was like perfect you + + + align:start position:0% +age 100 and it was like perfect you +could not have done it better so he's my + + align:start position:0% +could not have done it better so he's my + + + align:start position:0% +could not have done it better so he's my +inspiration I'm keep going I only have + + align:start position:0% +inspiration I'm keep going I only have + + + align:start position:0% +inspiration I'm keep going I only have +like 10 more years to get there well + + align:start position:0% +like 10 more years to get there well + + + align:start position:0% +like 10 more years to get there well +it's too many anyway okay Adam re all + + align:start position:0% +it's too many anyway okay Adam re all + + + align:start position:0% +it's too many anyway okay Adam re all +right + + align:start position:0% +right + + + align:start position:0% +right +so Adam art he created well that's the + + align:start position:0% +so Adam art he created well that's the + + + align:start position:0% +so Adam art he created well that's the +simplest the smallest now the next guy + + align:start position:0% +simplest the smallest now the next guy + + + align:start position:0% +simplest the smallest now the next guy +is gonna be four by four I'm going to + + align:start position:0% +is gonna be four by four I'm going to + + + align:start position:0% +is gonna be four by four I'm going to +put that so where I see a one I'm gonna + + align:start position:0% +put that so where I see a one I'm gonna + + + align:start position:0% +put that so where I see a one I'm gonna +put Adam artis 1 1 1 minus 1 1 1 1 minus + + align:start position:0% +put Adam artis 1 1 1 minus 1 1 1 1 minus + + + align:start position:0% +put Adam artis 1 1 1 minus 1 1 1 1 minus +1 and then when I see a minus I'm gonna + + align:start position:0% +1 and then when I see a minus I'm gonna + + + align:start position:0% +1 and then when I see a minus I'm gonna +put it in with a minus + + align:start position:0% + + + + align:start position:0% + +you saw that picture it was a picture of + + align:start position:0% +you saw that picture it was a picture of + + + align:start position:0% +you saw that picture it was a picture of +H 2 H 2 h 2 and minus H 2 that's what + + align:start position:0% +H 2 H 2 h 2 and minus H 2 that's what + + + align:start position:0% +H 2 H 2 h 2 and minus H 2 that's what +I've got there and I believe those + + align:start position:0% +I've got there and I believe those + + + align:start position:0% +I've got there and I believe those +columns are orthogonal right now what + + align:start position:0% +columns are orthogonal right now what + + + align:start position:0% +columns are orthogonal right now what +could I do + + align:start position:0% +could I do + + + align:start position:0% +could I do +well it's not quite an orthogonal matrix + + align:start position:0% +well it's not quite an orthogonal matrix + + + align:start position:0% +well it's not quite an orthogonal matrix +what do I have to do to make this isn't + + align:start position:0% +what do I have to do to make this isn't + + + align:start position:0% +what do I have to do to make this isn't +quite an orthogonal matrix either what + + align:start position:0% +quite an orthogonal matrix either what + + + align:start position:0% +quite an orthogonal matrix either what +what do I do to make that an orthogonal + + align:start position:0% +what do I do to make that an orthogonal + + + align:start position:0% +what do I do to make that an orthogonal +matrix / + + align:start position:0% +matrix / + + + align:start position:0% +matrix / +square root of two I need I need unit + + align:start position:0% +square root of two I need I need unit + + + align:start position:0% +square root of two I need I need unit +vectors there and here those lengths are + + align:start position:0% +vectors there and here those lengths are + + + align:start position:0% +vectors there and here those lengths are +1 squared 1 squared 4 square root of 4 + + align:start position:0% +1 squared 1 squared 4 square root of 4 + + + align:start position:0% +1 squared 1 squared 4 square root of 4 +is 2 so I better divided by the 2 there + + align:start position:0% +is 2 so I better divided by the 2 there + + + align:start position:0% +is 2 so I better divided by the 2 there +and now here I'm gonna here I'm up to + + align:start position:0% +and now here I'm gonna here I'm up to + + + align:start position:0% +and now here I'm gonna here I'm up to +yeah so that was that one don't tell me + + align:start position:0% +yeah so that was that one don't tell me + + + align:start position:0% +yeah so that was that one don't tell me +the next one up what's that going to be + + align:start position:0% +the next one up what's that going to be + + + align:start position:0% +the next one up what's that going to be +8 by 8 what's that so this is H 4 here + + align:start position:0% + + + + align:start position:0% + +oops 4 so tell me what I should do 4 8 + + align:start position:0% +oops 4 so tell me what I should do 4 8 + + + align:start position:0% +oops 4 so tell me what I should do 4 8 +by 8 you'll think this is like simple + + align:start position:0% +by 8 you'll think this is like simple + + + align:start position:0% +by 8 you'll think this is like simple +but that's that's a good thing to say + + align:start position:0% +but that's that's a good thing to say + + + align:start position:0% +but that's that's a good thing to say +about it you know they're in encoding + + align:start position:0% +about it you know they're in encoding + + + align:start position:0% +about it you know they're in encoding +theory all sorts of places you want + + align:start position:0% +theory all sorts of places you want + + + align:start position:0% +theory all sorts of places you want +matrices of ones and minus ones + + align:start position:0% +matrices of ones and minus ones + + + align:start position:0% +matrices of ones and minus ones +ok what's H 8 I'm gonna build it out of + + align:start position:0% +ok what's H 8 I'm gonna build it out of + + + align:start position:0% +ok what's H 8 I'm gonna build it out of +H 4 so what am I gonna what's it going + + align:start position:0% +H 4 so what am I gonna what's it going + + + align:start position:0% +H 4 so what am I gonna what's it going +to be I'm gonna put an H for there what + + align:start position:0% +to be I'm gonna put an H for there what + + + align:start position:0% +to be I'm gonna put an H for there what +am I going to put here another H 4 and + + align:start position:0% +am I going to put here another H 4 and + + + align:start position:0% +am I going to put here another H 4 and +up here another H 4 and finally here + + align:start position:0% +up here another H 4 and finally here + + + align:start position:0% +up here another H 4 and finally here +minus H and I think I've got orthogonal + + align:start position:0% +minus H and I think I've got orthogonal + + + align:start position:0% +minus H and I think I've got orthogonal +columns again right because the the + + align:start position:0% +columns again right because the the + + + align:start position:0% +columns again right because the the +columns within these dot products with + + align:start position:0% +columns within these dot products with + + + align:start position:0% +columns within these dot products with +themselves give 0 and 0 the dot products + + align:start position:0% +themselves give 0 and 0 the dot products + + + align:start position:0% +themselves give 0 and 0 the dot products +from these columns and these columns + + align:start position:0% +from these columns and these columns + + + align:start position:0% +from these columns and these columns +obviously have the minus and the dot + + align:start position:0% +obviously have the minus and the dot + + + align:start position:0% +obviously have the minus and the dot +products in here or 0 from that and 0 + + align:start position:0% +products in here or 0 from that and 0 + + + align:start position:0% +products in here or 0 from that and 0 +from that yeah it works and we could + + align:start position:0% +from that yeah it works and we could + + + align:start position:0% +from that yeah it works and we could +keep going to 16 and 32 and 64 but then + + align:start position:0% +keep going to 16 and 32 and 64 but then + + + align:start position:0% +keep going to 16 and 32 and 64 but then +up comes a question what about H 12 is + + align:start position:0% +up comes a question what about H 12 is + + + align:start position:0% +up comes a question what about H 12 is +there ones and minus ones matrix of size + + align:start position:0% +there ones and minus ones matrix of size + + + align:start position:0% +there ones and minus ones matrix of size +12 12 by 12 it + + align:start position:0% +12 12 by 12 it + + + align:start position:0% +12 12 by 12 it +it doesn't come directly from our little + + align:start position:0% +it doesn't come directly from our little + + + align:start position:0% +it doesn't come directly from our little +pattern which is doubling size every + + align:start position:0% +pattern which is doubling size every + + + align:start position:0% +pattern which is doubling size every +time but you could still hope and it + + align:start position:0% +time but you could still hope and it + + + align:start position:0% +time but you could still hope and it +works there is a I don't know what it is + + align:start position:0% +works there is a I don't know what it is + + + align:start position:0% +works there is a I don't know what it is +but there's a there's a matrix of ones + + align:start position:0% +but there's a there's a matrix of ones + + + align:start position:0% +but there's a there's a matrix of ones +and minus ones orthogonal twelve + + align:start position:0% +and minus ones orthogonal twelve + + + align:start position:0% +and minus ones orthogonal twelve +orthogonal columns so the answer is yes + + align:start position:0% +orthogonal columns so the answer is yes + + + align:start position:0% +orthogonal columns so the answer is yes +okay so we make an 1806 five conjecture + + align:start position:0% +okay so we make an 1806 five conjecture + + + align:start position:0% +okay so we make an 1806 five conjecture +every matrix every matrix size well not + + align:start position:0% +every matrix every matrix size well not + + + align:start position:0% +every matrix every matrix size well not +every matrix size because 3x3 is not + + align:start position:0% +every matrix size because 3x3 is not + + + align:start position:0% +every matrix size because 3x3 is not +going to work one by one is not going to + + align:start position:0% +going to work one by one is not going to + + + align:start position:0% +going to work one by one is not going to +work either but age twelve works + + align:start position:0% +work either but age twelve works + + + align:start position:0% +work either but age twelve works +h/h sixteen what's our conjecture we + + align:start position:0% +h/h sixteen what's our conjecture we + + + align:start position:0% +h/h sixteen what's our conjecture we +won't be the first conjecture --it that + + align:start position:0% +won't be the first conjecture --it that + + + align:start position:0% +won't be the first conjecture --it that +there is a ones and minus ones + + align:start position:0% +there is a ones and minus ones + + + align:start position:0% +there is a ones and minus ones +orthogonal matrix with orthogonal + + align:start position:0% +orthogonal matrix with orthogonal + + + align:start position:0% +orthogonal matrix with orthogonal +columns of every size n so always so so + + align:start position:0% +columns of every size n so always so so + + + align:start position:0% +columns of every size n so always so so +I'll start to conjecture always possible + + align:start position:0% + + + + align:start position:0% + +if and which is the size of the matrix + + align:start position:0% +if and which is the size of the matrix + + + align:start position:0% +if and which is the size of the matrix +let's say what would you guess just take + + align:start position:0% +let's say what would you guess just take + + + align:start position:0% +let's say what would you guess just take +a shot you won't be asked for a proof + + align:start position:0% +a shot you won't be asked for a proof + + + align:start position:0% +a shot you won't be asked for a proof +because nobody has the proof even well + + align:start position:0% +because nobody has the proof even well + + + align:start position:0% +because nobody has the proof even well +you could hope for even you could look + + align:start position:0% +you could hope for even you could look + + + align:start position:0% +you could hope for even you could look +for try six I guess would be the first + + align:start position:0% +for try six I guess would be the first + + + align:start position:0% +for try six I guess would be the first +guy there and I don't think it's + + align:start position:0% +guy there and I don't think it's + + + align:start position:0% +guy there and I don't think it's +possible I think six is not possible so + + align:start position:0% +possible I think six is not possible so + + + align:start position:0% +possible I think six is not possible so +every even sizes is I think not gonna + + align:start position:0% +every even sizes is I think not gonna + + + align:start position:0% +every even sizes is I think not gonna +work but it's natural idea to try what's + + align:start position:0% +work but it's natural idea to try what's + + + align:start position:0% +work but it's natural idea to try what's +the next thought every multiple of four + + align:start position:0% +the next thought every multiple of four + + + align:start position:0% +the next thought every multiple of four +if n over four is a whole number + + align:start position:0% + + + + align:start position:0% + +so but nobody has a way a systematic way + + align:start position:0% +so but nobody has a way a systematic way + + + align:start position:0% +so but nobody has a way a systematic way +to create these things so like some of + + align:start position:0% +to create these things so like some of + + + align:start position:0% +to create these things so like some of +them are we're at this point we're down + + align:start position:0% +them are we're at this point we're down + + + align:start position:0% +them are we're at this point we're down +to doing it one at a time and we're up + + align:start position:0% +to doing it one at a time and we're up + + + align:start position:0% +to doing it one at a time and we're up +to 668 but we haven't got that one yet + + align:start position:0% +to 668 but we haven't got that one yet + + + align:start position:0% +to 668 but we haven't got that one yet +isn't that crazy so all this is coming + + align:start position:0% +isn't that crazy so all this is coming + + + align:start position:0% +isn't that crazy so all this is coming +from Wikipedia my source of my short + + align:start position:0% +from Wikipedia my source of my short + + + align:start position:0% +from Wikipedia my source of my short +mice my source of all its good in + + align:start position:0% +mice my source of all its good in + + + align:start position:0% +mice my source of all its good in +mathematics is there on Wikipedia anyway + + align:start position:0% +mathematics is there on Wikipedia anyway + + + align:start position:0% +mathematics is there on Wikipedia anyway +this is the conjecture conjecture means + + align:start position:0% +this is the conjecture conjecture means + + + align:start position:0% +this is the conjecture conjecture means +you don't have any damn idea of whether + + align:start position:0% +you don't have any damn idea of whether + + + align:start position:0% +you don't have any damn idea of whether +it's true or not that every is that + + align:start position:0% +it's true or not that every is that + + + align:start position:0% +it's true or not that every is that +divisible by four yeah I guess it would + + align:start position:0% +divisible by four yeah I guess it would + + + align:start position:0% +divisible by four yeah I guess it would +be right 600 certainly is and 68 yeah + + align:start position:0% +be right 600 certainly is and 68 yeah + + + align:start position:0% +be right 600 certainly is and 68 yeah +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so I think that's the first one that's + + align:start position:0% +so I think that's the first one that's + + + align:start position:0% +so I think that's the first one that's +so anybody if if you find one of size + + align:start position:0% +so anybody if if you find one of size + + + align:start position:0% +so anybody if if you find one of size +six six you just skip the homework and + + align:start position:0% +six six you just skip the homework and + + + align:start position:0% +six six you just skip the homework and +tell us about that one but I don't think + + align:start position:0% +tell us about that one but I don't think + + + align:start position:0% +tell us about that one but I don't think +I'll assign them yeah I guess well yeah + + align:start position:0% +I'll assign them yeah I guess well yeah + + + align:start position:0% +I'll assign them yeah I guess well yeah +I must have searched for it online yeah + + align:start position:0% +I must have searched for it online yeah + + + align:start position:0% +I must have searched for it online yeah +anyway so those are the Adam are + + align:start position:0% +anyway so those are the Adam are + + + align:start position:0% +anyway so those are the Adam are +matrices now where else do I remember + + align:start position:0% +matrices now where else do I remember + + + align:start position:0% +matrices now where else do I remember +orthogonal matrices coming from well + + align:start position:0% +orthogonal matrices coming from well + + + align:start position:0% +orthogonal matrices coming from well +yeah really the biggest source of some + + align:start position:0% +yeah really the biggest source of some + + + align:start position:0% +yeah really the biggest source of some +what I'm looking for orthogonal matrices + + align:start position:0% +what I'm looking for orthogonal matrices + + + align:start position:0% +what I'm looking for orthogonal matrices +I'm looking for a basis of orthogonal + + align:start position:0% +I'm looking for a basis of orthogonal + + + align:start position:0% +I'm looking for a basis of orthogonal +vectors and we're in math am I going to + + align:start position:0% +vectors and we're in math am I going to + + + align:start position:0% +vectors and we're in math am I going to +find vectors that come out to be + + align:start position:0% +find vectors that come out to be + + + align:start position:0% +find vectors that come out to be +orthogonal we haven't seen that's the + + align:start position:0% +orthogonal we haven't seen that's the + + + align:start position:0% +orthogonal we haven't seen that's the +next section of the notes but maybe you + + align:start position:0% +next section of the notes but maybe you + + + align:start position:0% +next section of the notes but maybe you +were remembering where will we sort of + + align:start position:0% +were remembering where will we sort of + + + align:start position:0% +were remembering where will we sort of +like automatically show up with + + align:start position:0% +like automatically show up with + + + align:start position:0% +like automatically show up with +orthogonal vectors they could be the + + align:start position:0% +orthogonal vectors they could be the + + + align:start position:0% +orthogonal vectors they could be the +eigenvectors of symmetric matrix and + + align:start position:0% +eigenvectors of symmetric matrix and + + + align:start position:0% +eigenvectors of symmetric matrix and +that's where the most important ones + + align:start position:0% +that's where the most important ones + + + align:start position:0% +that's where the most important ones +come from oh I could tell you about + + align:start position:0% +come from oh I could tell you about + + + align:start position:0% +come from oh I could tell you about +wavelets though wavelets are more like + + align:start position:0% +wavelets though wavelets are more like + + + align:start position:0% +wavelets though wavelets are more like +this picture they're ones and minus ones + + align:start position:0% +this picture they're ones and minus ones + + + align:start position:0% +this picture they're ones and minus ones +or the simplest wavelets are ones + + align:start position:0% +or the simplest wavelets are ones + + + align:start position:0% +or the simplest wavelets are ones +- once can I cut it before I go on to + + align:start position:0% +- once can I cut it before I go on to + + + align:start position:0% +- once can I cut it before I go on to +the to the eigenvector business can I + + align:start position:0% +the to the eigenvector business can I + + + align:start position:0% +the to the eigenvector business can I +mention the wavelets matrices yeah these + + align:start position:0% +mention the wavelets matrices yeah these + + + align:start position:0% +mention the wavelets matrices yeah these +are these are really important simple + + align:start position:0% +are these are really important simple + + + align:start position:0% +are these are really important simple +and important constructions so wavelets + + align:start position:0% +and important constructions so wavelets + + + align:start position:0% +and important constructions so wavelets +let me yeah let me draw a picture of so + + align:start position:0% +let me yeah let me draw a picture of so + + + align:start position:0% +let me yeah let me draw a picture of so +so I'm going to come up with four-way + + align:start position:0% +so I'm going to come up with four-way + + + align:start position:0% +so I'm going to come up with four-way +I'll do the four by four case and and + + align:start position:0% +I'll do the four by four case and and + + + align:start position:0% +I'll do the four by four case and and +this is these these are the orthogonal + + align:start position:0% +this is these these are the orthogonal + + + align:start position:0% +this is these these are the orthogonal +guys and then the next one is up and + + align:start position:0% +guys and then the next one is up and + + + align:start position:0% +guys and then the next one is up and +down and 0 and the last one is 0 and up + + align:start position:0% +down and 0 and the last one is 0 and up + + + align:start position:0% +down and 0 and the last one is 0 and up +and down so that's that's for things but + + align:start position:0% +and down so that's that's for things but + + + align:start position:0% +and down so that's that's for things but +let me show you the matrix so I'll call + + align:start position:0% +let me show you the matrix so I'll call + + + align:start position:0% +let me show you the matrix so I'll call +it W for wavelets so that guy I'm + + align:start position:0% +it W for wavelets so that guy I'm + + + align:start position:0% +it W for wavelets so that guy I'm +thinking I was 1 1 1 1 this guy I'm + + align:start position:0% +thinking I was 1 1 1 1 this guy I'm + + + align:start position:0% +thinking I was 1 1 1 1 this guy I'm +thinking of as 1 1 minus 1 minus 1 it's + + align:start position:0% +thinking of as 1 1 minus 1 minus 1 it's + + + align:start position:0% +thinking of as 1 1 minus 1 minus 1 it's +looking sort of atom hard way but but + + align:start position:0% +looking sort of atom hard way but but + + + align:start position:0% +looking sort of atom hard way but but +there's a difference here this guy is 1 + + align:start position:0% +there's a difference here this guy is 1 + + + align:start position:0% +there's a difference here this guy is 1 +minus 1 0 0 so the wavelets rescale + + align:start position:0% +minus 1 0 0 so the wavelets rescale + + + align:start position:0% +minus 1 0 0 so the wavelets rescale +that's that's the difference between + + align:start position:0% +that's that's the difference between + + + align:start position:0% +that's that's the difference between +atom arden wavelets wavelets are scaling + + align:start position:0% +atom arden wavelets wavelets are scaling + + + align:start position:0% +atom arden wavelets wavelets are scaling +self scaling and what's the last guy + + align:start position:0% +self scaling and what's the last guy + + + align:start position:0% +self scaling and what's the last guy +here what's the fourth column from that + + align:start position:0% +here what's the fourth column from that + + + align:start position:0% +here what's the fourth column from that +fourth wavelet 0 0 1 minus 1 yeah so har + + align:start position:0% +fourth wavelet 0 0 1 minus 1 yeah so har + + + align:start position:0% +fourth wavelet 0 0 1 minus 1 yeah so har +came up with that this is the haar + + align:start position:0% +came up with that this is the haar + + + align:start position:0% +came up with that this is the haar +wavelet which was many years before the + + align:start position:0% +wavelet which was many years before the + + + align:start position:0% +wavelet which was many years before the +word wavelets was invented he came up + + align:start position:0% +word wavelets was invented he came up + + + align:start position:0% +word wavelets was invented he came up +with this construction the horror horror + + align:start position:0% +with this construction the horror horror + + + align:start position:0% +with this construction the horror horror +the horror matrix there are functions so + + align:start position:0% +the horror matrix there are functions so + + + align:start position:0% +the horror matrix there are functions so +they're very simple functions but you + + align:start position:0% +they're very simple functions but you + + + align:start position:0% +they're very simple functions but you +know you can + + align:start position:0% +know you can + + + align:start position:0% +know you can +that makes them usable that's the fact + + align:start position:0% +that makes them usable that's the fact + + + align:start position:0% +that makes them usable that's the fact +that they're so simple now I don't know + + align:start position:0% +that they're so simple now I don't know + + + align:start position:0% +that they're so simple now I don't know +if we want + + align:start position:0% +if we want + + + align:start position:0% +if we want +see the pattern an eight-by-eight but + + align:start position:0% +see the pattern an eight-by-eight but + + + align:start position:0% +see the pattern an eight-by-eight but +let me start the 8x8 so you you'll know + + align:start position:0% +let me start the 8x8 so you you'll know + + + align:start position:0% +let me start the 8x8 so you you'll know +what wavelets are about you'll know what + + align:start position:0% +what wavelets are about you'll know what + + + align:start position:0% +what wavelets are about you'll know what +these horror wavelets are about anyway + + align:start position:0% +these horror wavelets are about anyway + + + align:start position:0% +these horror wavelets are about anyway +they're they're the ones that were that + + align:start position:0% +they're they're the ones that were that + + + align:start position:0% +they're they're the ones that were that +we're kind of easy to visualize so let's + + align:start position:0% +we're kind of easy to visualize so let's + + + align:start position:0% +we're kind of easy to visualize so let's +this is if that's w-4 let's let's just + + align:start position:0% +this is if that's w-4 let's let's just + + + align:start position:0% +this is if that's w-4 let's let's just +take a minute + + align:start position:0% +take a minute + + + align:start position:0% +take a minute +it won't take long for WH okay so the + + align:start position:0% +it won't take long for WH okay so the + + + align:start position:0% +it won't take long for WH okay so the +first column is going to be eight ones + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and what's the next column gonna be four + + align:start position:0% +and what's the next column gonna be four + + + align:start position:0% +and what's the next column gonna be four +ones and four minus ones like so so four + + align:start position:0% +ones and four minus ones like so so four + + + align:start position:0% +ones and four minus ones like so so four +ones and four minus ones + + align:start position:0% +ones and four minus ones + + + align:start position:0% +ones and four minus ones +okay and now the next color - ones - - + + align:start position:0% +okay and now the next color - ones - - + + + align:start position:0% +okay and now the next color - ones - - +ones and zeros right 1 1 minus 1 minus 1 + + align:start position:0% +ones and zeros right 1 1 minus 1 minus 1 + + + align:start position:0% +ones and zeros right 1 1 minus 1 minus 1 +and 0 and the fourth will be zeros and + + align:start position:0% +and 0 and the fourth will be zeros and + + + align:start position:0% +and 0 and the fourth will be zeros and +two ones and two months we got half a + + align:start position:0% +two ones and two months we got half a + + + align:start position:0% +two ones and two months we got half a +matrix now now if we just tell me the + + align:start position:0% +matrix now now if we just tell me the + + + align:start position:0% +matrix now now if we just tell me the +fifth I'm what do you think what do I + + align:start position:0% +fifth I'm what do you think what do I + + + align:start position:0% +fifth I'm what do you think what do I +put in the fifth one so again it's gonna + + align:start position:0% +put in the fifth one so again it's gonna + + + align:start position:0% +put in the fifth one so again it's gonna +squeeze down and rescale and what's the + + align:start position:0% +squeeze down and rescale and what's the + + + align:start position:0% +squeeze down and rescale and what's the +fifth column up here that's gonna be + + align:start position:0% +fifth column up here that's gonna be + + + align:start position:0% +fifth column up here that's gonna be +ones and minus ones and zeros now so + + align:start position:0% +ones and minus ones and zeros now so + + + align:start position:0% +ones and minus ones and zeros now so +it's not at AMARG + + align:start position:0% +it's not at AMARG + + + align:start position:0% +it's not at AMARG +it's har and what should I put 1 1 how + + align:start position:0% +it's har and what should I put 1 1 how + + + align:start position:0% +it's har and what should I put 1 1 how +they start with 1 101 my yeah and then + + align:start position:0% +they start with 1 101 my yeah and then + + + align:start position:0% +they start with 1 101 my yeah and then +all those zeros oh yeah thanks perfect 1 + + align:start position:0% +all those zeros oh yeah thanks perfect 1 + + + align:start position:0% +all those zeros oh yeah thanks perfect 1 +minus 1 and they're all zeros and then + + align:start position:0% +minus 1 and they're all zeros and then + + + align:start position:0% +minus 1 and they're all zeros and then +the next three column says we'll have + + align:start position:0% +the next three column says we'll have + + + align:start position:0% +the next three column says we'll have +the 1 minus 1 here and the 1 minus 1 + + align:start position:0% +the 1 minus 1 here and the 1 minus 1 + + + align:start position:0% +the 1 minus 1 here and the 1 minus 1 +here and the 1 minus 1 here and I saw + + align:start position:0% +here and the 1 minus 1 here and I saw + + + align:start position:0% +here and the 1 minus 1 here and I saw +zeros yeah so you see the pattern it's + + align:start position:0% +zeros yeah so you see the pattern it's + + + align:start position:0% +zeros yeah so you see the pattern it's +scaling at every step + + align:start position:0% +scaling at every step + + + align:start position:0% +scaling at every step +and and the so that matrix has the + + align:start position:0% +and and the so that matrix has the + + + align:start position:0% +and and the so that matrix has the +advantage of being quite sparse sort of + + align:start position:0% +advantage of being quite sparse sort of + + + align:start position:0% +advantage of being quite sparse sort of +this this in my mind is a or but for + + align:start position:0% +this this in my mind is a or but for + + + align:start position:0% +this this in my mind is a or but for +ones that's involved with like taking + + align:start position:0% +ones that's involved with like taking + + + align:start position:0% +ones that's involved with like taking +the average then this guy is like taking + + align:start position:0% +the average then this guy is like taking + + + align:start position:0% +the average then this guy is like taking +the differences differences between + + align:start position:0% +the differences differences between + + + align:start position:0% +the differences differences between +those and those and then this is like + + align:start position:0% +those and those and then this is like + + + align:start position:0% +those and those and then this is like +taking the difference at a smaller scale + + align:start position:0% +taking the difference at a smaller scale + + + align:start position:0% +taking the difference at a smaller scale +I'm not also at a smaller scale so + + align:start position:0% +I'm not also at a smaller scale so + + + align:start position:0% +I'm not also at a smaller scale so +that's what we keep doing yeah yeah + + align:start position:0% +that's what we keep doing yeah yeah + + + align:start position:0% +that's what we keep doing yeah yeah +so that's wavelets it looks so simple + + align:start position:0% +so that's wavelets it looks so simple + + + align:start position:0% +so that's wavelets it looks so simple +right but at the just a one minute + + align:start position:0% +right but at the just a one minute + + + align:start position:0% +right but at the just a one minute +history of wavelet Sohar invented this + + align:start position:0% +history of wavelet Sohar invented this + + + align:start position:0% +history of wavelet Sohar invented this +in like 1910 I mean along forever but + + align:start position:0% +in like 1910 I mean along forever but + + + align:start position:0% +in like 1910 I mean along forever but +then you wanted wavelets that were a + + align:start position:0% +then you wanted wavelets that were a + + + align:start position:0% +then you wanted wavelets that were a +little better and not just ones and + + align:start position:0% +little better and not just ones and + + + align:start position:0% +little better and not just ones and +minus ones and zeros and it that took + + align:start position:0% +minus ones and zeros and it that took + + + align:start position:0% +minus ones and zeros and it that took +some some a lot of thinking a lot of + + align:start position:0% +some some a lot of thinking a lot of + + + align:start position:0% +some some a lot of thinking a lot of +people were searching for it and Ingrid + + align:start position:0% +people were searching for it and Ingrid + + + align:start position:0% +people were searching for it and Ingrid +dobashi + + align:start position:0% +dobashi + + + align:start position:0% +dobashi +so I'll just put her name became famous + + align:start position:0% +so I'll just put her name became famous + + + align:start position:0% +so I'll just put her name became famous +for finding them so in about 1988 she + + align:start position:0% +for finding them so in about 1988 she + + + align:start position:0% +for finding them so in about 1988 she +found a lot of families of wavelets and + + align:start position:0% +found a lot of families of wavelets and + + + align:start position:0% +found a lot of families of wavelets and +when I say wavelets she found a whole + + align:start position:0% +when I say wavelets she found a whole + + + align:start position:0% +when I say wavelets she found a whole +lot of orthogonal matrices that were + + align:start position:0% +lot of orthogonal matrices that were + + + align:start position:0% +lot of orthogonal matrices that were +that had good properties yep so that's + + align:start position:0% +that had good properties yep so that's + + + align:start position:0% +that had good properties yep so that's +that's the wave of a picture okay now to + + align:start position:0% +that's the wave of a picture okay now to + + + align:start position:0% +that's the wave of a picture okay now to +close today and to connect with the next + + align:start position:0% +close today and to connect with the next + + + align:start position:0% +close today and to connect with the next +lecture on eigenvalues eigenvectors + + align:start position:0% +lecture on eigenvalues eigenvectors + + + align:start position:0% +lecture on eigenvalues eigenvectors +positive definite matrices we're really + + align:start position:0% +positive definite matrices we're really + + + align:start position:0% +positive definite matrices we're really +getting to the heart of things here + + align:start position:0% +getting to the heart of things here + + + align:start position:0% +getting to the heart of things here +let me follow through on that idea + + align:start position:0% +let me follow through on that idea + + + align:start position:0% +let me follow through on that idea +so the eigenvectors of symmetric matrix + + align:start position:0% +so the eigenvectors of symmetric matrix + + + align:start position:0% +so the eigenvectors of symmetric matrix +but also of an orthogonal matrix are + + align:start position:0% +but also of an orthogonal matrix are + + + align:start position:0% +but also of an orthogonal matrix are +orthogonal and that is really where + + align:start position:0% +orthogonal and that is really where + + + align:start position:0% +orthogonal and that is really where +people where you can invent because you + + align:start position:0% +people where you can invent because you + + + align:start position:0% +people where you can invent because you +don't have to work hard you just find a + + align:start position:0% +don't have to work hard you just find a + + + align:start position:0% +don't have to work hard you just find a +symmetric matrix its eigenvectors are + + align:start position:0% +symmetric matrix its eigenvectors are + + + align:start position:0% +symmetric matrix its eigenvectors are +automatically orthogonal that doesn't + + align:start position:0% +automatically orthogonal that doesn't + + + align:start position:0% +automatically orthogonal that doesn't +mean they're great for for use but some + + align:start position:0% +mean they're great for for use but some + + + align:start position:0% +mean they're great for for use but some +of them are really important and that + + align:start position:0% +of them are really important and that + + + align:start position:0% +of them are really important and that +may be the most important of all is the + + align:start position:0% +may be the most important of all is the + + + align:start position:0% +may be the most important of all is the +fourier so you probably have seen + + align:start position:0% +fourier so you probably have seen + + + align:start position:0% +fourier so you probably have seen +Fourier series sines and cosines those + + align:start position:0% +Fourier series sines and cosines those + + + align:start position:0% +Fourier series sines and cosines those +guys are orthogonal functions but + + align:start position:0% +guys are orthogonal functions but + + + align:start position:0% +guys are orthogonal functions but +discrete Fourier series is what + + align:start position:0% +discrete Fourier series is what + + + align:start position:0% +discrete Fourier series is what +everybody computes and those are + + align:start position:0% +everybody computes and those are + + + align:start position:0% +everybody computes and those are +orthogonal vectors so the orthogonal + + align:start position:0% +orthogonal vectors so the orthogonal + + + align:start position:0% +orthogonal vectors so the orthogonal +vectors that go into the discrete + + align:start position:0% +vectors that go into the discrete + + + align:start position:0% +vectors that go into the discrete +Fourier transform and and then they're + + align:start position:0% +Fourier transform and and then they're + + + align:start position:0% +Fourier transform and and then they're +done at high speed by the fast Fourier + + align:start position:0% +done at high speed by the fast Fourier + + + align:start position:0% +done at high speed by the fast Fourier +transform + + align:start position:0% +transform + + + align:start position:0% +transform +those are eigenvectors of q eigenvectors + + align:start position:0% +those are eigenvectors of q eigenvectors + + + align:start position:0% +those are eigenvectors of q eigenvectors +of the right q so let me just invent the + + align:start position:0% +of the right q so let me just invent the + + + align:start position:0% +of the right q so let me just invent the +right tell you the right q that get + + align:start position:0% +right tell you the right q that get + + + align:start position:0% +right tell you the right q that get +whose eigenvectors so so i here we go + + align:start position:0% +whose eigenvectors so so i here we go + + + align:start position:0% +whose eigenvectors so so i here we go +I can vectors of Q let me you will just + + align:start position:0% +I can vectors of Q let me you will just + + + align:start position:0% +I can vectors of Q let me you will just +be amazed by how simple this matrix is + + align:start position:0% +be amazed by how simple this matrix is + + + align:start position:0% +be amazed by how simple this matrix is +it's just that matrix it's a called a + + align:start position:0% +it's just that matrix it's a called a + + + align:start position:0% +it's just that matrix it's a called a +permutation matrix it just puts the + + align:start position:0% +permutation matrix it just puts the + + + align:start position:0% +permutation matrix it just puts the +those are the four eight for Fourier + + align:start position:0% + + + + align:start position:0% + +discrete discrete let me put their word + + align:start position:0% +discrete discrete let me put their word + + + align:start position:0% +discrete discrete let me put their word +discrete up here transfer + + align:start position:0% + + + + align:start position:0% + +so I really meant to put discrete + + align:start position:0% +so I really meant to put discrete + + + align:start position:0% +so I really meant to put discrete +Fourier transform yeah + + align:start position:0% +Fourier transform yeah + + + align:start position:0% +Fourier transform yeah +the eigenvectors of that matrix first of + + align:start position:0% +the eigenvectors of that matrix first of + + + align:start position:0% +the eigenvectors of that matrix first of +all they are orthogonal and then second + + align:start position:0% +all they are orthogonal and then second + + + align:start position:0% +all they are orthogonal and then second +and more important they're they're + + align:start position:0% +and more important they're they're + + + align:start position:0% +and more important they're they're +tremendously useful they're the they're + + align:start position:0% +tremendously useful they're the they're + + + align:start position:0% +tremendously useful they're the they're +the heart of signal processing you know + + align:start position:0% +the heart of signal processing you know + + + align:start position:0% +the heart of signal processing you know +in in signal processing they just take + + align:start position:0% +in in signal processing they just take + + + align:start position:0% +in in signal processing they just take +the discrete Fourier transform of a + + align:start position:0% +the discrete Fourier transform of a + + + align:start position:0% +the discrete Fourier transform of a +vector before they even look at it I + + align:start position:0% +vector before they even look at it I + + + align:start position:0% +vector before they even look at it I +mean it's like that's the way to see it + + align:start position:0% +mean it's like that's the way to see it + + + align:start position:0% +mean it's like that's the way to see it +is split it into its frequencies and + + align:start position:0% +is split it into its frequencies and + + + align:start position:0% +is split it into its frequencies and +that's what the eigenvectors of this + + align:start position:0% +that's what the eigenvectors of this + + + align:start position:0% +that's what the eigenvectors of this +will do so we're going to see the + + align:start position:0% +will do so we're going to see the + + + align:start position:0% +will do so we're going to see the +discrete Fourier transform and but my + + align:start position:0% +discrete Fourier transform and but my + + + align:start position:0% +discrete Fourier transform and but my +point here is to know that they're + + align:start position:0% +point here is to know that they're + + + align:start position:0% +point here is to know that they're +orthogonal is just comes out of this + + align:start position:0% +orthogonal is just comes out of this + + + align:start position:0% +orthogonal is just comes out of this +fact that the eigenvectors are + + align:start position:0% +fact that the eigenvectors are + + + align:start position:0% +fact that the eigenvectors are +orthogonal for any Q and that is + + align:start position:0% +orthogonal for any Q and that is + + + align:start position:0% +orthogonal for any Q and that is +certainly a Q everybody can see that + + align:start position:0% +certainly a Q everybody can see that + + + align:start position:0% +certainly a Q everybody can see that +those columns are orthogonal the columns + + align:start position:0% +those columns are orthogonal the columns + + + align:start position:0% +those columns are orthogonal the columns +of a print that's a permutation matrix + + align:start position:0% +of a print that's a permutation matrix + + + align:start position:0% +of a print that's a permutation matrix +right it's a you've taken the columns of + + align:start position:0% +right it's a you've taken the columns of + + + align:start position:0% +right it's a you've taken the columns of +the identity which are totally + + align:start position:0% +the identity which are totally + + + align:start position:0% +the identity which are totally +orthogonal and you just put them in a + + align:start position:0% +orthogonal and you just put them in a + + + align:start position:0% +orthogonal and you just put them in a +different order so a permutation matrix + + align:start position:0% +different order so a permutation matrix + + + align:start position:0% +different order so a permutation matrix +is a reordering of the identity matrix + + align:start position:0% +is a reordering of the identity matrix + + + align:start position:0% +is a reordering of the identity matrix +it's got to be a q and therefore its + + align:start position:0% +it's got to be a q and therefore its + + + align:start position:0% +it's got to be a q and therefore its +eigenvectors are orthogonal and they're + + align:start position:0% +eigenvectors are orthogonal and they're + + + align:start position:0% +eigenvectors are orthogonal and they're +just the winners i mean that the the + + align:start position:0% +just the winners i mean that the the + + + align:start position:0% +just the winners i mean that the the +matrix of the fourier matrix with those + + align:start position:0% +matrix of the fourier matrix with those + + + align:start position:0% +matrix of the fourier matrix with those +four eigen vectors in it I'll show you + + align:start position:0% +four eigen vectors in it I'll show you + + + align:start position:0% +four eigen vectors in it I'll show you +now okay so this is really we're + + align:start position:0% +now okay so this is really we're + + + align:start position:0% +now okay so this is really we're +finishing today by leading into + + align:start position:0% +finishing today by leading into + + + align:start position:0% +finishing today by leading into +Wednesday + + align:start position:0% +Wednesday + + + align:start position:0% +Wednesday +I can vectors and eigen values and we + + align:start position:0% +I can vectors and eigen values and we + + + align:start position:0% +I can vectors and eigen values and we +happen to be doing eigen vectors and + + align:start position:0% +happen to be doing eigen vectors and + + + align:start position:0% +happen to be doing eigen vectors and +eigen values of a queue not today of an + + align:start position:0% +eigen values of a queue not today of an + + + align:start position:0% +eigen values of a queue not today of an +S well most of the time it's a symmetric + + align:start position:0% +S well most of the time it's a symmetric + + + align:start position:0% +S well most of the time it's a symmetric +matrix whose eigenvectors we take but + + align:start position:0% +matrix whose eigenvectors we take but + + + align:start position:0% +matrix whose eigenvectors we take but +here that happens to be a q can I show + + align:start position:0% +here that happens to be a q can I show + + + align:start position:0% +here that happens to be a q can I show +you the eigenvectors + + align:start position:0% +you the eigenvectors + + + align:start position:0% +you the eigenvectors +the four eigenvectors of that now oh the + + align:start position:0% +the four eigenvectors of that now oh the + + + align:start position:0% +the four eigenvectors of that now oh the +complex number I is going to come in you + + align:start position:0% +complex number I is going to come in you + + + align:start position:0% +complex number I is going to come in you +have to you have to let it in here yeah + + align:start position:0% +have to you have to let it in here yeah + + + align:start position:0% +have to you have to let it in here yeah +sorry ma if s if s is a real symmetric + + align:start position:0% +sorry ma if s if s is a real symmetric + + + align:start position:0% +sorry ma if s if s is a real symmetric +matrix its eigenvectors are real but if + + align:start position:0% +matrix its eigenvectors are real but if + + + align:start position:0% +matrix its eigenvectors are real but if +q is a orthogonal matrix its + + align:start position:0% +q is a orthogonal matrix its + + + align:start position:0% +q is a orthogonal matrix its +eigenvectors even though it's you know + + align:start position:0% +eigenvectors even though it's you know + + + align:start position:0% +eigenvectors even though it's you know +you couldn't ask for a more real matrix + + align:start position:0% +you couldn't ask for a more real matrix + + + align:start position:0% +you couldn't ask for a more real matrix +than that but its eigenvectors are at + + align:start position:0% +than that but its eigenvectors are at + + + align:start position:0% +than that but its eigenvectors are at +least yeah the one the good way are + + align:start position:0% +least yeah the one the good way are + + + align:start position:0% +least yeah the one the good way are +complex numbers so can I show you the + + align:start position:0% +complex numbers so can I show you the + + + align:start position:0% +complex numbers so can I show you the +eigenvectors of so again overall the + + align:start position:0% +eigenvectors of so again overall the + + + align:start position:0% +eigenvectors of so again overall the +point today is to see orthogonal + + align:start position:0% +point today is to see orthogonal + + + align:start position:0% +point today is to see orthogonal +matrices so I'll just repeat now while I + + align:start position:0% +matrices so I'll just repeat now while I + + + align:start position:0% +matrices so I'll just repeat now while I +can + + align:start position:0% +can + + + align:start position:0% +can +rotations here reflections wavelets the + + align:start position:0% +rotations here reflections wavelets the + + + align:start position:0% +rotations here reflections wavelets the +householder idea of reflections of big + + align:start position:0% +householder idea of reflections of big + + + align:start position:0% +householder idea of reflections of big +large matrices that have this form I + + align:start position:0% +large matrices that have this form I + + + align:start position:0% +large matrices that have this form I +minus 2 uu transpose orthogonal and now + + align:start position:0% +minus 2 uu transpose orthogonal and now + + + align:start position:0% +minus 2 uu transpose orthogonal and now +we're going to see the big guys the the + + align:start position:0% +we're going to see the big guys the the + + + align:start position:0% +we're going to see the big guys the the +eigenvectors of q right yes oh yeah we + + align:start position:0% +eigenvectors of q right yes oh yeah we + + + align:start position:0% +eigenvectors of q right yes oh yeah we +don't have orthonormal that's right we + + align:start position:0% +don't have orthonormal that's right we + + + align:start position:0% +don't have orthonormal that's right we +don't have orthonormal I better divide + + align:start position:0% +don't have orthonormal I better divide + + + align:start position:0% +don't have orthonormal I better divide +by square root of 8 right oh yeah so + + align:start position:0% +by square root of 8 right oh yeah so + + + align:start position:0% +by square root of 8 right oh yeah so +you're right sorry I thought I'd get + + align:start position:0% +you're right sorry I thought I'd get + + + align:start position:0% +you're right sorry I thought I'd get +away with that but I didn't yeah so + + align:start position:0% +away with that but I didn't yeah so + + + align:start position:0% +away with that but I didn't yeah so +these guys are screws of 8 so are these + + align:start position:0% +these guys are screws of 8 so are these + + + align:start position:0% +these guys are screws of 8 so are these +but these guys are fruits of 4 and these + + align:start position:0% +but these guys are fruits of 4 and these + + + align:start position:0% +but these guys are fruits of 4 and these +guys are screw to - thank you absolutely + + align:start position:0% +guys are screw to - thank you absolutely + + + align:start position:0% +guys are screw to - thank you absolutely +right absolutely yeah + + align:start position:0% +right absolutely yeah + + + align:start position:0% +right absolutely yeah +okay so what are the eigenvectors of a + + align:start position:0% +okay so what are the eigenvectors of a + + + align:start position:0% +okay so what are the eigenvectors of a +of a permutation this is going to be + + align:start position:0% +of a permutation this is going to be + + + align:start position:0% +of a permutation this is going to be +nice to see and I'll use the matrix F + + align:start position:0% +nice to see and I'll use the matrix F + + + align:start position:0% +nice to see and I'll use the matrix F +for the eigenvector matrix of that of + + align:start position:0% +for the eigenvector matrix of that of + + + align:start position:0% +for the eigenvector matrix of that of +that of that queue up there and F is for + + align:start position:0% +that of that queue up there and F is for + + + align:start position:0% +that of that queue up there and F is for +for you and it be the four by four for a + + align:start position:0% +for you and it be the four by four for a + + + align:start position:0% +for you and it be the four by four for a +matrix okay what are the eigenvectors of + + align:start position:0% +matrix okay what are the eigenvectors of + + + align:start position:0% +matrix okay what are the eigenvectors of +Q okay so Q is a permutation so like I'm + + align:start position:0% +Q okay so Q is a permutation so like I'm + + + align:start position:0% +Q okay so Q is a permutation so like I'm +gonna ask you for one eigenvector of + + align:start position:0% +gonna ask you for one eigenvector of + + + align:start position:0% +gonna ask you for one eigenvector of +every permutation matrix what what + + align:start position:0% +every permutation matrix what what + + + align:start position:0% +every permutation matrix what what +vector can you tell me that it actually + + align:start position:0% +vector can you tell me that it actually + + + align:start position:0% +vector can you tell me that it actually +the eigenvalue will be one what vector + + align:start position:0% +the eigenvalue will be one what vector + + + align:start position:0% +the eigenvalue will be one what vector +can you tell me where if i permute it I + + align:start position:0% +can you tell me where if i permute it I + + + align:start position:0% +can you tell me where if i permute it I +don't change it one one one one it's + + align:start position:0% +don't change it one one one one it's + + + align:start position:0% +don't change it one one one one it's +like it's everywhere here one one one + + align:start position:0% +like it's everywhere here one one one + + + align:start position:0% +like it's everywhere here one one one +one so that's the zero frequency Fourier + + align:start position:0% +one so that's the zero frequency Fourier + + + align:start position:0% +one so that's the zero frequency Fourier +vector + + align:start position:0% +vector + + + align:start position:0% +vector +the constant vector all ones everybody + + align:start position:0% +the constant vector all ones everybody + + + align:start position:0% +the constant vector all ones everybody +sees that if I I multiply by Q it + + align:start position:0% +sees that if I I multiply by Q it + + + align:start position:0% +sees that if I I multiply by Q it +doesn't change okay now the next one + + align:start position:0% +doesn't change okay now the next one + + + align:start position:0% +doesn't change okay now the next one +I'll show you the for now the next one + + align:start position:0% +I'll show you the for now the next one + + + align:start position:0% +I'll show you the for now the next one +will be one I I squared and I cubed + + align:start position:0% + + + + align:start position:0% + +of course I squared I don't know how + + align:start position:0% +of course I squared I don't know how + + + align:start position:0% +of course I squared I don't know how +many course 6j people are in this + + align:start position:0% +many course 6j people are in this + + + align:start position:0% +many course 6j people are in this +audience but this is a math building we + + align:start position:0% +audience but this is a math building we + + + align:start position:0% +audience but this is a math building we +pay for it it's to 190 and it's I in + + align:start position:0% +pay for it it's to 190 and it's I in + + + align:start position:0% +pay for it it's to 190 and it's I in +this room yeah + + align:start position:0% +this room yeah + + + align:start position:0% +this room yeah +so anyway I is the first letter in in + + align:start position:0% +so anyway I is the first letter in in + + + align:start position:0% +so anyway I is the first letter in in +what imaginary thank you the first + + align:start position:0% +what imaginary thank you the first + + + align:start position:0% +what imaginary thank you the first +letter in imaginary you can't say + + align:start position:0% +letter in imaginary you can't say + + + align:start position:0% +letter in imaginary you can't say +imaginary so so so that's it okay and + + align:start position:0% +imaginary so so so that's it okay and + + + align:start position:0% +imaginary so so so that's it okay and +then the next one is one I squared I + + align:start position:0% +then the next one is one I squared I + + + align:start position:0% +then the next one is one I squared I +fourth I six and the next one is one I + + align:start position:0% +fourth I six and the next one is one I + + + align:start position:0% +fourth I six and the next one is one I +cubed I six an i-9 + + align:start position:0% +cubed I six an i-9 + + + align:start position:0% +cubed I six an i-9 +that's isn't that just beautiful and you + + align:start position:0% +that's isn't that just beautiful and you + + + align:start position:0% +that's isn't that just beautiful and you +could + + align:start position:0% +could + + + align:start position:0% +could +show that every one of those four + + align:start position:0% +show that every one of those four + + + align:start position:0% +show that every one of those four +columns if you multiply them by Q you + + align:start position:0% +columns if you multiply them by Q you + + + align:start position:0% +columns if you multiply them by Q you +would get the eigenvalues and you would + + align:start position:0% +would get the eigenvalues and you would + + + align:start position:0% +would get the eigenvalues and you would +see that it's an eigenvector and this is + + align:start position:0% +see that it's an eigenvector and this is + + + align:start position:0% +see that it's an eigenvector and this is +just sort of like a discrete fourier + + align:start position:0% +just sort of like a discrete fourier + + + align:start position:0% +just sort of like a discrete fourier +stuff and you know instead of e to the I + + align:start position:0% +stuff and you know instead of e to the I + + + align:start position:0% +stuff and you know instead of e to the I +II to the IX e to the 2i X e to the 3 IX + + align:start position:0% +II to the IX e to the 2i X e to the 3 IX + + + align:start position:0% +II to the IX e to the 2i X e to the 3 IX +and so on we just have vectors but I so + + align:start position:0% +and so on we just have vectors but I so + + + align:start position:0% +and so on we just have vectors but I so +those are the four eigenvectors of the + + align:start position:0% +those are the four eigenvectors of the + + + align:start position:0% +those are the four eigenvectors of the +of that of that permutation and those + + align:start position:0% +of that of that permutation and those + + + align:start position:0% +of that of that permutation and those +are orthogonal because I just check that + + align:start position:0% +are orthogonal because I just check that + + + align:start position:0% +are orthogonal because I just check that +how do you know that this first column + + align:start position:0% +how do you know that this first column + + + align:start position:0% +how do you know that this first column +in the second well I should really say + + align:start position:0% +in the second well I should really say + + + align:start position:0% +in the second well I should really say +0th column and first column if I'm if + + align:start position:0% +0th column and first column if I'm if + + + align:start position:0% +0th column and first column if I'm if +I'm talking frequencies do you see that + + align:start position:0% +I'm talking frequencies do you see that + + + align:start position:0% +I'm talking frequencies do you see that +that's orthogonal to that well Y is one + + align:start position:0% +that's orthogonal to that well Y is one + + + align:start position:0% +that's orthogonal to that well Y is one +plus I plus I squared plus I cube equal + + align:start position:0% +plus I plus I squared plus I cube equal + + + align:start position:0% +plus I plus I squared plus I cube equal +zero that's the dot product this is + + align:start position:0% +zero that's the dot product this is + + + align:start position:0% +zero that's the dot product this is +column 1 dot column 2 yeah yeah you're + + align:start position:0% +column 1 dot column 2 yeah yeah you're + + + align:start position:0% +column 1 dot column 2 yeah yeah you're +right + + align:start position:0% +right + + + align:start position:0% +right +this happens to come out 0 is that right + + align:start position:0% + + + + align:start position:0% + +that'll come out 0 but somebody + + align:start position:0% +that'll come out 0 but somebody + + + align:start position:0% +that'll come out 0 but somebody +mentioned that this isn't right this is + + align:start position:0% +mentioned that this isn't right this is + + + align:start position:0% +mentioned that this isn't right this is +I mean that it's true that that came out + + align:start position:0% +I mean that it's true that that came out + + + align:start position:0% +I mean that it's true that that came out +0 but when I have imaginary vector + + align:start position:0% +0 but when I have imaginary vector + + + align:start position:0% +0 but when I have imaginary vector +imaginary numbers so anywhere around + + align:start position:0% +imaginary numbers so anywhere around + + + align:start position:0% +imaginary numbers so anywhere around +this isn't the correct dot product to + + align:start position:0% +this isn't the correct dot product to + + + align:start position:0% +this isn't the correct dot product to +test orthogonal if I have imaginary + + align:start position:0% +test orthogonal if I have imaginary + + + align:start position:0% +test orthogonal if I have imaginary +complex vectors if I have complex + + align:start position:0% +complex vectors if I have complex + + + align:start position:0% +complex vectors if I have complex +numbers complex vectors I should test + + align:start position:0% +numbers complex vectors I should test + + + align:start position:0% +numbers complex vectors I should test +column 1 conjugate dotted with column 2 + + align:start position:0% +column 1 conjugate dotted with column 2 + + + align:start position:0% +column 1 conjugate dotted with column 2 +column I conjugate well let me take + + align:start position:0% +column I conjugate well let me take + + + align:start position:0% +column I conjugate well let me take +column C what which one shall I take + + align:start position:0% +column C what which one shall I take + + + align:start position:0% +column C what which one shall I take +maybe that guy in that guy many of them + + align:start position:0% +maybe that guy in that guy many of them + + + align:start position:0% +maybe that guy in that guy many of them +you luck out here but but really I + + align:start position:0% +you luck out here but but really I + + + align:start position:0% +you luck out here but but really I +should be + + align:start position:0% +should be + + + align:start position:0% +should be +taking their conjugate so so so these + + align:start position:0% +taking their conjugate so so so these + + + align:start position:0% +taking their conjugate so so so these +ones but the thing is the country the + + align:start position:0% +ones but the thing is the country the + + + align:start position:0% +ones but the thing is the country the +complex conjugate of one is one so that + + align:start position:0% +complex conjugate of one is one so that + + + align:start position:0% +complex conjugate of one is one so that +was that was okay but in general if I + + align:start position:0% +was that was okay but in general if I + + + align:start position:0% +was that was okay but in general if I +wanted to take column two dotted with + + align:start position:0% +wanted to take column two dotted with + + + align:start position:0% +wanted to take column two dotted with +column I don't know maybe four would be + + align:start position:0% +column I don't know maybe four would be + + + align:start position:0% +column I don't know maybe four would be +a little dodgy yeah look look what + + align:start position:0% +a little dodgy yeah look look what + + + align:start position:0% +a little dodgy yeah look look what +happens + + align:start position:0% +happens + + + align:start position:0% +happens +take that column and that column take + + align:start position:0% +take that column and that column take + + + align:start position:0% +take that column and that column take +their dot product do it the wrong way so + + align:start position:0% +their dot product do it the wrong way so + + + align:start position:0% +their dot product do it the wrong way so +what's the wrong way + + align:start position:0% +what's the wrong way + + + align:start position:0% +what's the wrong way +forget about the complex conjugate and + + align:start position:0% +forget about the complex conjugate and + + + align:start position:0% +forget about the complex conjugate and +just do it the usual way so one times + + align:start position:0% +just do it the usual way so one times + + + align:start position:0% +just do it the usual way so one times +one is one I times I cube is 1 I squared + + align:start position:0% +one is one I times I cube is 1 I squared + + + align:start position:0% +one is one I times I cube is 1 I squared +times I six is one I'm getting all ones + + align:start position:0% +times I six is one I'm getting all ones + + + align:start position:0% +times I six is one I'm getting all ones +I'm not getting a orthogonality there + + align:start position:0% +I'm not getting a orthogonality there + + + align:start position:0% +I'm not getting a orthogonality there +and that's because I forgot that I + + align:start position:0% +and that's because I forgot that I + + + align:start position:0% +and that's because I forgot that I +should take the complex conjugate well + + align:start position:0% +should take the complex conjugate well + + + align:start position:0% +should take the complex conjugate well +of these guys one I should take minus I + + align:start position:0% +of these guys one I should take minus I + + + align:start position:0% +of these guys one I should take minus I +minus I square minus i well that's real + + align:start position:0% +minus I square minus i well that's real + + + align:start position:0% +minus I square minus i well that's real +so it's okay - they're so so minus I + + align:start position:0% +so it's okay - they're so so minus I + + + align:start position:0% +so it's okay - they're so so minus I +squared is still minus one so now if I + + align:start position:0% +squared is still minus one so now if I + + + align:start position:0% +squared is still minus one so now if I +do it it comes out zero so so let me + + align:start position:0% +do it it comes out zero so so let me + + + align:start position:0% +do it it comes out zero so so let me +repeat again let me just make this + + align:start position:0% +repeat again let me just make this + + + align:start position:0% +repeat again let me just make this +statement if Q transpose Q is I and Q X + + align:start position:0% +statement if Q transpose Q is I and Q X + + + align:start position:0% +statement if Q transpose Q is I and Q X +is lambda X and Q Y is a different eigen + + align:start position:0% +is lambda X and Q Y is a different eigen + + + align:start position:0% +is lambda X and Q Y is a different eigen +value Y okay so I'm I'm setting up the + + align:start position:0% +value Y okay so I'm I'm setting up the + + + align:start position:0% +value Y okay so I'm I'm setting up the +main fact that in the last minute I'm + + align:start position:0% +main fact that in the last minute I'm + + + align:start position:0% +main fact that in the last minute I'm +just gonna write down so I have an + + align:start position:0% +just gonna write down so I have an + + + align:start position:0% +just gonna write down so I have an +orthogonal matrix I have an eigenvector + + align:start position:0% +orthogonal matrix I have an eigenvector + + + align:start position:0% +orthogonal matrix I have an eigenvector +with eigenvalue lambda I have another + + align:start position:0% +with eigenvalue lambda I have another + + + align:start position:0% +with eigenvalue lambda I have another +eigenvector with a different eigen value + + align:start position:0% +eigenvector with a different eigen value + + + align:start position:0% +eigenvector with a different eigen value +mu then the claim is that what is the + + align:start position:0% +mu then the claim is that what is the + + + align:start position:0% +mu then the claim is that what is the +claim about the eigenvectors so here's + + align:start position:0% +claim about the eigenvectors so here's + + + align:start position:0% +claim about the eigenvectors so here's +has one eigen this has an eigen value + + align:start position:0% +has one eigen this has an eigen value + + + align:start position:0% +has one eigen this has an eigen value +this has a different eigen value + + align:start position:0% +this has a different eigen value + + + align:start position:0% +this has a different eigen value +I need them to be different to really + + align:start position:0% +I need them to be different to really + + + align:start position:0% +I need them to be different to really +know that they're the XS and the Y's + + align:start position:0% +know that they're the XS and the Y's + + + align:start position:0% +know that they're the XS and the Y's +can't be the same so what is it that I + + align:start position:0% +can't be the same so what is it that I + + + align:start position:0% +can't be the same so what is it that I +want to show yes that X I have to + + align:start position:0% +want to show yes that X I have to + + + align:start position:0% +want to show yes that X I have to +remember to do that X transpose Y is 0 + + align:start position:0% +remember to do that X transpose Y is 0 + + + align:start position:0% +remember to do that X transpose Y is 0 +that's orthogonality that's + + align:start position:0% +that's orthogonality that's + + + align:start position:0% +that's orthogonality that's +orthogonality for complex vectors I have + + align:start position:0% +orthogonality for complex vectors I have + + + align:start position:0% +orthogonality for complex vectors I have +to remember to take the to change every + + align:start position:0% +to remember to take the to change every + + + align:start position:0% +to remember to take the to change every +I to a minus I in one of the vectors and + + align:start position:0% +I to a minus I in one of the vectors and + + + align:start position:0% +I to a minus I in one of the vectors and +I can prove that fact by playing with + + align:start position:0% +I can prove that fact by playing with + + + align:start position:0% +I can prove that fact by playing with +these these by playing with starting + + align:start position:0% +these these by playing with starting + + + align:start position:0% +these these by playing with starting +from here I can get to that ok that's it + + align:start position:0% +from here I can get to that ok that's it + + + align:start position:0% +from here I can get to that ok that's it +we've done a lot today a lot of stuff + + align:start position:0% +we've done a lot today a lot of stuff + + + align:start position:0% +we've done a lot today a lot of stuff +about orthogonal matrices important ones + + align:start position:0% +about orthogonal matrices important ones + + + align:start position:0% +about orthogonal matrices important ones +and the sources of important ones I ghen + + align:start position:0% +and the sources of important ones I ghen + + + align:start position:0% +and the sources of important ones I ghen +vectors and so it'll be eigenvectors on + + align:start position:0% +vectors and so it'll be eigenvectors on + + + align:start position:0% +vectors and so it'll be eigenvectors on +Wednesday \ No newline at end of file diff --git a/Y6J8I056Ffw.txt b/Y6J8I056Ffw.txt new file mode 100644 index 0000000000000000000000000000000000000000..1da7d6d93877beab7e26c2229489dff3bb012412 --- /dev/null +++ b/Y6J8I056Ffw.txt @@ -0,0 +1,251 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT open courseware continue + + align:start position:0% +will help MIT open courseware continue + + + align:start position:0% +will help MIT open courseware continue +to offer highquality educational + + align:start position:0% +to offer highquality educational + + + align:start position:0% +to offer highquality educational +resources for free to make a donation or + + align:start position:0% +resources for free to make a donation or + + + align:start position:0% +resources for free to make a donation or +view additional materials from hundreds + + align:start position:0% +view additional materials from hundreds + + + align:start position:0% +view additional materials from hundreds +of MIT courses visit MIT opencourseware + + align:start position:0% +of MIT courses visit MIT opencourseware + + + align:start position:0% +of MIT courses visit MIT opencourseware +at + + align:start position:0% + + + + align:start position:0% + +ocw.mit.edu so the question was if you + + align:start position:0% +ocw.mit.edu so the question was if you + + + align:start position:0% +ocw.mit.edu so the question was if you +have this these two um these two lines + + align:start position:0% +have this these two um these two lines + + + align:start position:0% +have this these two um these two lines +right here which I'll just put them up + + align:start position:0% +right here which I'll just put them up + + + align:start position:0% +right here which I'll just put them up +here just so what's bigger type five + + align:start position:0% +here just so what's bigger type five + + + align:start position:0% +here just so what's bigger type five +print 3.0 minus1 what is going to be the + + align:start position:0% +print 3.0 minus1 what is going to be the + + + align:start position:0% +print 3.0 minus1 what is going to be the +output so if I run this in the editor so + + align:start position:0% +output so if I run this in the editor so + + + align:start position:0% +output so if I run this in the editor so +for these types of problems you can + + align:start position:0% +for these types of problems you can + + + align:start position:0% +for these types of problems you can +always check yourself and this comes + + align:start position:0% +always check yourself and this comes + + + align:start position:0% +always check yourself and this comes +back to if you're new to programming + + align:start position:0% +back to if you're new to programming + + + align:start position:0% +back to if you're new to programming +don't be afraid to try it out don't ask + + align:start position:0% +don't be afraid to try it out don't ask + + + align:start position:0% +don't be afraid to try it out don't ask +me don't ask your your neighbor just + + align:start position:0% +me don't ask your your neighbor just + + + align:start position:0% +me don't ask your your neighbor just +type it into the into the shell and hit + + align:start position:0% +type it into the into the shell and hit + + + align:start position:0% +type it into the into the shell and hit +run and and then you get to see what the + + align:start position:0% +run and and then you get to see what the + + + align:start position:0% +run and and then you get to see what the +answer is so the answer to this question + + align:start position:0% +answer is so the answer to this question + + + align:start position:0% +answer is so the answer to this question +is going to be 2.0 right and let's see + + align:start position:0% +is going to be 2.0 right and let's see + + + align:start position:0% +is going to be 2.0 right and let's see +are we right yeah great 75% of the + + align:start position:0% +are we right yeah great 75% of the + + + align:start position:0% +are we right yeah great 75% of the +people got it right + + align:start position:0% +people got it right + + + align:start position:0% +people got it right +perfect um so if you didn't get it right + + align:start position:0% +perfect um so if you didn't get it right + + + align:start position:0% +perfect um so if you didn't get it right +just to explain again the reason why + + align:start position:0% +just to explain again the reason why + + + align:start position:0% +just to explain again the reason why +this doesn't get printed out is because + + align:start position:0% +this doesn't get printed out is because + + + align:start position:0% +this doesn't get printed out is because +we never actually had a print statement + + align:start position:0% +we never actually had a print statement + + + align:start position:0% +we never actually had a print statement +okay so if you want to show something to + + align:start position:0% +okay so if you want to show something to + + + align:start position:0% +okay so if you want to show something to +the the console you need to use a print + + align:start position:0% +the the console you need to use a print + + + align:start position:0% +the the console you need to use a print +statement \ No newline at end of file diff --git a/YLp8RziRbpg.txt b/YLp8RziRbpg.txt new file mode 100644 index 0000000000000000000000000000000000000000..6bd0b07a9fb39ae85043cea482dd41f0ce461ee0 --- /dev/null +++ b/YLp8RziRbpg.txt @@ -0,0 +1,8643 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT OpenCourseWare continue to + + align:start position:0% +will help MIT OpenCourseWare continue to + + + align:start position:0% +will help MIT OpenCourseWare continue to +offer high quality educational resources + + align:start position:0% +offer high quality educational resources + + + align:start position:0% +offer high quality educational resources +for free + + align:start position:0% +for free + + + align:start position:0% +for free +to make a donation or to view additional + + align:start position:0% +to make a donation or to view additional + + + align:start position:0% +to make a donation or to view additional +materials from hundreds of MIT courses + + align:start position:0% +materials from hundreds of MIT courses + + + align:start position:0% +materials from hundreds of MIT courses +visit MIT opencourseware at ocw.mit.edu + + align:start position:0% + + + + align:start position:0% + +today we launched into radioactive decay + + align:start position:0% +today we launched into radioactive decay + + + align:start position:0% +today we launched into radioactive decay +and so this is you know kind of what + + align:start position:0% +and so this is you know kind of what + + + align:start position:0% +and so this is you know kind of what +makes us us in this field right now that + + align:start position:0% +makes us us in this field right now that + + + align:start position:0% +makes us us in this field right now that +you've learned the general q equation + + align:start position:0% +you've learned the general q equation + + + align:start position:0% +you've learned the general q equation +we're going to look at some very simple + + align:start position:0% +we're going to look at some very simple + + + align:start position:0% +we're going to look at some very simple +specific cases and specifically all the + + align:start position:0% +specific cases and specifically all the + + + align:start position:0% +specific cases and specifically all the +different things that can come flying + + align:start position:0% +different things that can come flying + + + align:start position:0% +different things that can come flying +out of nuclei and the orbiting electrons + + align:start position:0% +out of nuclei and the orbiting electrons + + + align:start position:0% +out of nuclei and the orbiting electrons +around them first I'd like to try and + + align:start position:0% +around them first I'd like to try and + + + align:start position:0% +around them first I'd like to try and +develop a generalized decayed diagram + + align:start position:0% +develop a generalized decayed diagram + + + align:start position:0% +develop a generalized decayed diagram +what are all the different ways that + + align:start position:0% +what are all the different ways that + + + align:start position:0% +what are all the different ways that +nuclei can decay and I had written one + + align:start position:0% +nuclei can decay and I had written one + + + align:start position:0% +nuclei can decay and I had written one +of these up to show on the slides and my + + align:start position:0% +of these up to show on the slides and my + + + align:start position:0% +of these up to show on the slides and my +one-year-old son fixed it with a bunch + + align:start position:0% +one-year-old son fixed it with a bunch + + + align:start position:0% +one-year-old son fixed it with a bunch +of markers and crayons so I think we're + + align:start position:0% +of markers and crayons so I think we're + + + align:start position:0% +of markers and crayons so I think we're +gonna have to redo this from scratch so + + align:start position:0% +gonna have to redo this from scratch so + + + align:start position:0% +gonna have to redo this from scratch so +let's say you had a generalized unstable + + align:start position:0% +let's say you had a generalized unstable + + + align:start position:0% +let's say you had a generalized unstable +nucleus over here and we're gonna start + + align:start position:0% +nucleus over here and we're gonna start + + + align:start position:0% +nucleus over here and we're gonna start +drawing a generalize decay diagram + + align:start position:0% +drawing a generalize decay diagram + + + align:start position:0% +drawing a generalize decay diagram +you'll see decay diagrams well much like + + align:start position:0% +you'll see decay diagrams well much like + + + align:start position:0% +you'll see decay diagrams well much like +these I've already shown you a couple of + + align:start position:0% +these I've already shown you a couple of + + + align:start position:0% +these I've already shown you a couple of +these like these decay diagrams for + + align:start position:0% +these like these decay diagrams for + + + align:start position:0% +these like these decay diagrams for +uranium-235 as soon as I clone my screen + + align:start position:0% +uranium-235 as soon as I clone my screen + + + align:start position:0% +uranium-235 as soon as I clone my screen +so you can see it there are a couple of + + align:start position:0% +so you can see it there are a couple of + + + align:start position:0% +so you can see it there are a couple of +axes that aren't drawn on these decay + + align:start position:0% +axes that aren't drawn on these decay + + + align:start position:0% +axes that aren't drawn on these decay +diagrams that'll help you interpret them + + align:start position:0% +diagrams that'll help you interpret them + + + align:start position:0% +diagrams that'll help you interpret them +and the first one the imaginary y axis + + align:start position:0% +and the first one the imaginary y axis + + + align:start position:0% +and the first one the imaginary y axis +is an order of increasing energy and the + + align:start position:0% +is an order of increasing energy and the + + + align:start position:0% +is an order of increasing energy and the +second imaginary y axis is Z atomic + + align:start position:0% +second imaginary y axis is Z atomic + + + align:start position:0% +second imaginary y axis is Z atomic +number so this will help you determine + + align:start position:0% +number so this will help you determine + + + align:start position:0% +number so this will help you determine +how we read these and how to actually + + align:start position:0% +how we read these and how to actually + + + align:start position:0% +how we read these and how to actually +write them now what are some of the + + align:start position:0% +write them now what are some of the + + + align:start position:0% +write them now what are some of the +different ways you've heard of things + + align:start position:0% +different ways you've heard of things + + + align:start position:0% +different ways you've heard of things +that can radioactively decay or that you + + align:start position:0% +that can radioactively decay or that you + + + align:start position:0% +that can radioactively decay or that you +might have read from the reading this + + align:start position:0% +might have read from the reading this + + + align:start position:0% +might have read from the reading this +yellow mout alpha decay so in alpha + + align:start position:0% +yellow mout alpha decay so in alpha + + + align:start position:0% +yellow mout alpha decay so in alpha +decay what actually happens let's say + + align:start position:0% +decay what actually happens let's say + + + align:start position:0% +decay what actually happens let's say +that we had a parent nucleus with atomic + + align:start position:0% +that we had a parent nucleus with atomic + + + align:start position:0% +that we had a parent nucleus with atomic +number Z and mass number a what does it + + align:start position:0% +number Z and mass number a what does it + + + align:start position:0% +number Z and mass number a what does it +change into + + align:start position:0% + + + + align:start position:0% + +anyone know what an alpha particle + + align:start position:0% +anyone know what an alpha particle + + + align:start position:0% +anyone know what an alpha particle +consists of yeah a helium nucleus so + + align:start position:0% +consists of yeah a helium nucleus so + + + align:start position:0% +consists of yeah a helium nucleus so +let's just say helium well this will be + + align:start position:0% +let's just say helium well this will be + + + align:start position:0% +let's just say helium well this will be +a 4 and a 2 and there's going to be some + + align:start position:0% +a 4 and a 2 and there's going to be some + + + align:start position:0% +a 4 and a 2 and there's going to be some +daughter nucleus we don't know what with + + align:start position:0% +daughter nucleus we don't know what with + + + align:start position:0% +daughter nucleus we don't know what with +Z minus 2 protons and a minus for total + + align:start position:0% +Z minus 2 protons and a minus for total + + + align:start position:0% +Z minus 2 protons and a minus for total +nucleons so if we were to describe alpha + + align:start position:0% +nucleons so if we were to describe alpha + + + align:start position:0% +nucleons so if we were to describe alpha +decay on a decay diagram where would we + + align:start position:0% +decay on a decay diagram where would we + + + align:start position:0% +decay on a decay diagram where would we +write the final state of this alpha + + align:start position:0% +write the final state of this alpha + + + align:start position:0% +write the final state of this alpha +decay new alpha decayed daughter nucleus + + align:start position:0% +decay new alpha decayed daughter nucleus + + + align:start position:0% +decay new alpha decayed daughter nucleus +to the left or to the right I know it's + + align:start position:0% +to the left or to the right I know it's + + + align:start position:0% +to the left or to the right I know it's +like 9 a.m. but someone just shout it + + align:start position:0% +like 9 a.m. but someone just shout it + + + align:start position:0% +like 9 a.m. but someone just shout it +out you'd have to raise your hand to the + + align:start position:0% +out you'd have to raise your hand to the + + + align:start position:0% +out you'd have to raise your hand to the +left yep something that's decreasing in + + align:start position:0% +left yep something that's decreasing in + + + align:start position:0% +left yep something that's decreasing in +Z and also decreasing in energy we would + + align:start position:0% +Z and also decreasing in energy we would + + + align:start position:0% +Z and also decreasing in energy we would +draw an alpha decay like this to the + + align:start position:0% +draw an alpha decay like this to the + + + align:start position:0% +draw an alpha decay like this to the +left so let's say this would be + + align:start position:0% +left so let's say this would be + + + align:start position:0% +left so let's say this would be +something more stable with a Z - to make + + align:start position:0% +something more stable with a Z - to make + + + align:start position:0% +something more stable with a Z - to make +that clear and then a minus 4 what are + + align:start position:0% +that clear and then a minus 4 what are + + + align:start position:0% +that clear and then a minus 4 what are +some other ways things can decay I heard + + align:start position:0% +some other ways things can decay I heard + + + align:start position:0% +some other ways things can decay I heard +a whisper beta decay so what happens in + + align:start position:0% +a whisper beta decay so what happens in + + + align:start position:0% +a whisper beta decay so what happens in +usually by beta decay we're referring to + + align:start position:0% +usually by beta decay we're referring to + + + align:start position:0% +usually by beta decay we're referring to +beta minus decay which would be the + + align:start position:0% +beta minus decay which would be the + + + align:start position:0% +beta minus decay which would be the +emission of an electron from the nucleus + + align:start position:0% +emission of an electron from the nucleus + + + align:start position:0% +emission of an electron from the nucleus +again the differ what's the difference + + align:start position:0% +again the differ what's the difference + + + align:start position:0% +again the differ what's the difference +what's the physical difference between a + + align:start position:0% +what's the physical difference between a + + + align:start position:0% +what's the physical difference between a +beta particle and an electron nothing + + align:start position:0% +beta particle and an electron nothing + + + align:start position:0% +beta particle and an electron nothing +what's the nomenclature difference the + + align:start position:0% +what's the nomenclature difference the + + + align:start position:0% +what's the nomenclature difference the +beta comes from the nucleus otherwise + + align:start position:0% +beta comes from the nucleus otherwise + + + align:start position:0% +beta comes from the nucleus otherwise +when they come out they're kind of + + align:start position:0% +when they come out they're kind of + + + align:start position:0% +when they come out they're kind of +indistinguishable so what happens in + + align:start position:0% +indistinguishable so what happens in + + + align:start position:0% +indistinguishable so what happens in +beta decay let's say we have the same + + align:start position:0% +beta decay let's say we have the same + + + align:start position:0% +beta decay let's say we have the same +parent nucleus starting with Z a we know + + align:start position:0% +parent nucleus starting with Z a we know + + + align:start position:0% +parent nucleus starting with Z a we know +it emits an electron with no mass and + + align:start position:0% +it emits an electron with no mass and + + + align:start position:0% +it emits an electron with no mass and +what else this is just a matter of + + align:start position:0% +what else this is just a matter of + + + align:start position:0% +what else this is just a matter of +conservation of things here yep + + align:start position:0% +conservation of things here yep + + + align:start position:0% +conservation of things here yep +there is an anti-neutrino which has + + align:start position:0% +there is an anti-neutrino which has + + + align:start position:0% +there is an anti-neutrino which has +pretty close to no mass and no charge + + align:start position:0% +pretty close to no mass and no charge + + + align:start position:0% +pretty close to no mass and no charge +and what about this daughter nucleus how + + align:start position:0% +and what about this daughter nucleus how + + + align:start position:0% +and what about this daughter nucleus how +many protons and total nucleons would it + + align:start position:0% +many protons and total nucleons would it + + + align:start position:0% +many protons and total nucleons would it +have yeah should have one more proton + + align:start position:0% +have yeah should have one more proton + + + align:start position:0% +have yeah should have one more proton +and how many more total nucleons the + + align:start position:0% +and how many more total nucleons the + + + align:start position:0% +and how many more total nucleons the +same yep like that and so how would we + + align:start position:0% +same yep like that and so how would we + + + align:start position:0% +same yep like that and so how would we +draw a beta decay on this generalized + + align:start position:0% +draw a beta decay on this generalized + + + align:start position:0% +draw a beta decay on this generalized +diagram to the left or to the right to + + align:start position:0% +diagram to the left or to the right to + + + align:start position:0% +diagram to the left or to the right to +the right it's increasing in Z I haven't + + align:start position:0% +the right it's increasing in Z I haven't + + + align:start position:0% +the right it's increasing in Z I haven't +defined any scale so let's just say + + align:start position:0% +defined any scale so let's just say + + + align:start position:0% +defined any scale so let's just say +that's a change of 0 that's 1 that's 2 + + align:start position:0% +that's a change of 0 that's 1 that's 2 + + + align:start position:0% +that's a change of 0 that's 1 that's 2 +and that's plus 1 that's plus 2 + + align:start position:0% +and that's plus 1 that's plus 2 + + + align:start position:0% +and that's plus 1 that's plus 2 +hopefully we won't get to today so a + + align:start position:0% +hopefully we won't get to today so a + + + align:start position:0% +hopefully we won't get to today so a +beta decay would proceed thusly so you'd + + align:start position:0% +beta decay would proceed thusly so you'd + + + align:start position:0% +beta decay would proceed thusly so you'd +have some other stable nucleus with Z + + align:start position:0% +have some other stable nucleus with Z + + + align:start position:0% +have some other stable nucleus with Z +plus 1 and mass number 8 + + align:start position:0% +plus 1 and mass number 8 + + + align:start position:0% +plus 1 and mass number 8 +what are some other decays you might + + align:start position:0% +what are some other decays you might + + + align:start position:0% +what are some other decays you might +have heard of before electron capture so + + align:start position:0% +have heard of before electron capture so + + + align:start position:0% +have heard of before electron capture so +in electron capture what actually + + align:start position:0% +in electron capture what actually + + + align:start position:0% +in electron capture what actually +happens start with the same parent + + align:start position:0% +happens start with the same parent + + + align:start position:0% +happens start with the same parent +nucleus in this case the nucleus + + align:start position:0% +nucleus in this case the nucleus + + + align:start position:0% +nucleus in this case the nucleus +actually captures an electron from one + + align:start position:0% +actually captures an electron from one + + + align:start position:0% +actually captures an electron from one +of the inner orbitals and so that in + + align:start position:0% +of the inner orbitals and so that in + + + align:start position:0% +of the inner orbitals and so that in +effect like neutralizes a proton right + + align:start position:0% +effect like neutralizes a proton right + + + align:start position:0% +effect like neutralizes a proton right +in terms of charge so what do we end up + + align:start position:0% +in terms of charge so what do we end up + + + align:start position:0% +in terms of charge so what do we end up +with + + align:start position:0% + + + + align:start position:0% + +yep so we'd have some daughter nucleus + + align:start position:0% +yep so we'd have some daughter nucleus + + + align:start position:0% +yep so we'd have some daughter nucleus +if it neutralizes a proton we'd have one + + align:start position:0% +if it neutralizes a proton we'd have one + + + align:start position:0% +if it neutralizes a proton we'd have one +fewer protons and then how many total + + align:start position:0% +fewer protons and then how many total + + + align:start position:0% +fewer protons and then how many total +nucleons the same yep there we go and so + + align:start position:0% +nucleons the same yep there we go and so + + + align:start position:0% +nucleons the same yep there we go and so +if we were to draw electron capture on + + align:start position:0% +if we were to draw electron capture on + + + align:start position:0% +if we were to draw electron capture on +this map we would have one fewer proton + + align:start position:0% +this map we would have one fewer proton + + + align:start position:0% +this map we would have one fewer proton +so we could have some sort of decay by + + align:start position:0% +so we could have some sort of decay by + + + align:start position:0% +so we could have some sort of decay by +electron capture anything else what + + align:start position:0% +electron capture anything else what + + + align:start position:0% +electron capture anything else what +other particles can be emitted from a + + align:start position:0% +other particles can be emitted from a + + + align:start position:0% +other particles can be emitted from a +nucleus yeah positrons so let's get this + + align:start position:0% +nucleus yeah positrons so let's get this + + + align:start position:0% +nucleus yeah positrons so let's get this +list going up yeah so if we start off + + align:start position:0% +list going up yeah so if we start off + + + align:start position:0% +list going up yeah so if we start off +with a parent Z and a we know we emit a + + align:start position:0% +with a parent Z and a we know we emit a + + + align:start position:0% +with a parent Z and a we know we emit a +positron which is the antimatter + + align:start position:0% +positron which is the antimatter + + + align:start position:0% +positron which is the antimatter +equivalent of an electron so same + + align:start position:0% +equivalent of an electron so same + + + align:start position:0% +equivalent of an electron so same +general characteristics except opposite + + align:start position:0% +general characteristics except opposite + + + align:start position:0% +general characteristics except opposite +charge in this case we'll give it a zero + + align:start position:0% +charge in this case we'll give it a zero + + + align:start position:0% +charge in this case we'll give it a zero +protons and zero neutrons and we end up + + align:start position:0% +protons and zero neutrons and we end up + + + align:start position:0% +protons and zero neutrons and we end up +with well the same daughter nucleus so + + align:start position:0% +with well the same daughter nucleus so + + + align:start position:0% +with well the same daughter nucleus so +we could say that this precedes by + + align:start position:0% +we could say that this precedes by + + + align:start position:0% +we could say that this precedes by +positron creation or electron capture + + align:start position:0% +positron creation or electron capture + + + align:start position:0% +positron creation or electron capture +it's the same process or the same ending + + align:start position:0% +it's the same process or the same ending + + + align:start position:0% +it's the same process or the same ending +state but can you have positrons in any + + align:start position:0% +state but can you have positrons in any + + + align:start position:0% +state but can you have positrons in any +possible decay we actually went over + + align:start position:0% +possible decay we actually went over + + + align:start position:0% +possible decay we actually went over +this once + + align:start position:0% +this once + + + align:start position:0% +this once +anyone remember yeah so you're saying + + align:start position:0% +anyone remember yeah so you're saying + + + align:start position:0% +anyone remember yeah so you're saying +your head no + + align:start position:0% + + + + align:start position:0% + +we'll get back into that you're right so + + align:start position:0% +we'll get back into that you're right so + + + align:start position:0% +we'll get back into that you're right so +we'll put a little box around this + + align:start position:0% +we'll put a little box around this + + + align:start position:0% +we'll put a little box around this +because you have to have a certain + + align:start position:0% +because you have to have a certain + + + align:start position:0% +because you have to have a certain +amount of energy in order to create the + + align:start position:0% +amount of energy in order to create the + + + align:start position:0% +amount of energy in order to create the +positron and what else what about the + + align:start position:0% +positron and what else what about the + + + align:start position:0% +positron and what else what about the +the easiest one what else can be emitted + + align:start position:0% +the easiest one what else can be emitted + + + align:start position:0% +the easiest one what else can be emitted +from a nucleus I heard a couple things + + align:start position:0% +from a nucleus I heard a couple things + + + align:start position:0% +from a nucleus I heard a couple things +neutrons so certainly if you emit a + + align:start position:0% +neutrons so certainly if you emit a + + + align:start position:0% +neutrons so certainly if you emit a +neutron there are some very unstable + + align:start position:0% +neutron there are some very unstable + + + align:start position:0% +neutron there are some very unstable +nuclei like helium five which exists for + + align:start position:0% +nuclei like helium five which exists for + + + align:start position:0% +nuclei like helium five which exists for +what ten to the minus twenty six seconds + + align:start position:0% +what ten to the minus twenty six seconds + + + align:start position:0% +what ten to the minus twenty six seconds +or something that could have been a + + align:start position:0% +or something that could have been a + + + align:start position:0% +or something that could have been a +neutron if we start off with Z an a then + + align:start position:0% +neutron if we start off with Z an a then + + + align:start position:0% +neutron if we start off with Z an a then +we'll start off with a neutron and a + + align:start position:0% +we'll start off with a neutron and a + + + align:start position:0% +we'll start off with a neutron and a +daughter with the same Z and a minus one + + align:start position:0% +daughter with the same Z and a minus one + + + align:start position:0% +daughter with the same Z and a minus one +total so what would that look like on a + + align:start position:0% +total so what would that look like on a + + + align:start position:0% +total so what would that look like on a +decay chain you don't usually see this + + align:start position:0% +decay chain you don't usually see this + + + align:start position:0% +decay chain you don't usually see this +but we're draw it anyway it would go + + align:start position:0% +but we're draw it anyway it would go + + + align:start position:0% +but we're draw it anyway it would go +straight down right so it'll be some + + align:start position:0% +straight down right so it'll be some + + + align:start position:0% +straight down right so it'll be some +other nucleus so the same Z but an a + + align:start position:0% +other nucleus so the same Z but an a + + + align:start position:0% +other nucleus so the same Z but an a +minus one and it could decay by Neutron + + align:start position:0% +minus one and it could decay by Neutron + + + align:start position:0% +minus one and it could decay by Neutron +emission yeah that totally happens if + + align:start position:0% +emission yeah that totally happens if + + + align:start position:0% +emission yeah that totally happens if +you look at the very very right edge of + + align:start position:0% +you look at the very very right edge of + + + align:start position:0% +you look at the very very right edge of +the table of nuclides let's go back to + + align:start position:0% +the table of nuclides let's go back to + + + align:start position:0% +the table of nuclides let's go back to +the home page for that and look at the + + align:start position:0% +the home page for that and look at the + + + align:start position:0% +the home page for that and look at the +super Neutron rich like helium ten who's + + align:start position:0% +super Neutron rich like helium ten who's + + + align:start position:0% +super Neutron rich like helium ten who's +ever heard of this right doesn't even + + align:start position:0% +ever heard of this right doesn't even + + + align:start position:0% +ever heard of this right doesn't even +say let's say two neutrons so this is so + + align:start position:0% +say let's say two neutrons so this is so + + + align:start position:0% +say let's say two neutrons so this is so +unstable that it just immediately spits + + align:start position:0% +unstable that it just immediately spits + + + align:start position:0% +unstable that it just immediately spits +out two neutrons so yeah these things + + align:start position:0% +out two neutrons so yeah these things + + + align:start position:0% +out two neutrons so yeah these things +happen you won't tend to see this decay + + align:start position:0% +happen you won't tend to see this decay + + + align:start position:0% +happen you won't tend to see this decay +in textbooks because it only happens for + + align:start position:0% +in textbooks because it only happens for + + + align:start position:0% +in textbooks because it only happens for +exceptionally unstable nuclei but yeah + + align:start position:0% +exceptionally unstable nuclei but yeah + + + align:start position:0% +exceptionally unstable nuclei but yeah +that's true + + align:start position:0% +that's true + + + align:start position:0% +that's true +it does happen what else could happen + + align:start position:0% + + + + align:start position:0% + +remember we've been talking about yeah + + align:start position:0% +remember we've been talking about yeah + + + align:start position:0% +remember we've been talking about yeah +right + + align:start position:0% +right + + + align:start position:0% +right +it could be gammas and so I'll make one + + align:start position:0% +it could be gammas and so I'll make one + + + align:start position:0% +it could be gammas and so I'll make one +little extra piece here for a gamma + + align:start position:0% +little extra piece here for a gamma + + + align:start position:0% +little extra piece here for a gamma +decay which is nothing more than a + + align:start position:0% +decay which is nothing more than a + + + align:start position:0% +decay which is nothing more than a +photon emitted from the nucleus we start + + align:start position:0% +photon emitted from the nucleus we start + + + align:start position:0% +photon emitted from the nucleus we start +off with a parent Z and a + + align:start position:0% +off with a parent Z and a + + + align:start position:0% +off with a parent Z and a +and this becomes well what should I even + + align:start position:0% +and this becomes well what should I even + + + align:start position:0% +and this becomes well what should I even +write daughter nucleus I see some people + + align:start position:0% +write daughter nucleus I see some people + + + align:start position:0% +write daughter nucleus I see some people +shaking their heads no why not yep + + align:start position:0% + + + + align:start position:0% + +yep so very close you have the same atom + + align:start position:0% +yep so very close you have the same atom + + + align:start position:0% +yep so very close you have the same atom +so let's say the same parent with the + + align:start position:0% +so let's say the same parent with the + + + align:start position:0% +so let's say the same parent with the +same number of protons same number of + + align:start position:0% +same number of protons same number of + + + align:start position:0% +same number of protons same number of +total nucleons and I'll just correct + + align:start position:0% +total nucleons and I'll just correct + + + align:start position:0% +total nucleons and I'll just correct +that to say one of its nuclei is at a + + align:start position:0% +that to say one of its nuclei is at a + + + align:start position:0% +that to say one of its nuclei is at a +lower energy state but otherwise + + align:start position:0% +lower energy state but otherwise + + + align:start position:0% +lower energy state but otherwise +everything is completely correct so why + + align:start position:0% +everything is completely correct so why + + + align:start position:0% +everything is completely correct so why +don't we put a little star here to say + + align:start position:0% +don't we put a little star here to say + + + align:start position:0% +don't we put a little star here to say +that that was at an excited state just + + align:start position:0% +that that was at an excited state just + + + align:start position:0% +that that was at an excited state just +like electrons can be promoted to outer + + align:start position:0% +like electrons can be promoted to outer + + + align:start position:0% +like electrons can be promoted to outer +shells pick up a little bit of energy so + + align:start position:0% +shells pick up a little bit of energy so + + + align:start position:0% +shells pick up a little bit of energy so +can nucleon so can protons and neutrons + + align:start position:0% +can nucleon so can protons and neutrons + + + align:start position:0% +can nucleon so can protons and neutrons +and this is so going to be a subject of + + align:start position:0% +and this is so going to be a subject of + + + align:start position:0% +and this is so going to be a subject of +well great discussion in 22:02 + + align:start position:0% +well great discussion in 22:02 + + + align:start position:0% +well great discussion in 22:02 +for now all you have to know is that + + align:start position:0% +for now all you have to know is that + + + align:start position:0% +for now all you have to know is that +nucleons like electrons can occupy + + align:start position:0% +nucleons like electrons can occupy + + + align:start position:0% +nucleons like electrons can occupy +higher energy states and when they fall + + align:start position:0% +higher energy states and when they fall + + + align:start position:0% +higher energy states and when they fall +down to lower energy state they can + + align:start position:0% +down to lower energy state they can + + + align:start position:0% +down to lower energy state they can +release that energy in the form of a + + align:start position:0% +release that energy in the form of a + + + align:start position:0% +release that energy in the form of a +gamma ray so you could also have let's + + align:start position:0% +gamma ray so you could also have let's + + + align:start position:0% +gamma ray so you could also have let's +say squiggly line gamma decay to + + align:start position:0% +say squiggly line gamma decay to + + + align:start position:0% +say squiggly line gamma decay to +something stable and so this right here + + align:start position:0% +something stable and so this right here + + + align:start position:0% +something stable and so this right here +would be the generalized decay diagram + + align:start position:0% + + + + align:start position:0% + +anyone ever heard of one isotope that + + align:start position:0% +anyone ever heard of one isotope that + + + align:start position:0% +anyone ever heard of one isotope that +undergoes all these possible decay + + align:start position:0% +undergoes all these possible decay + + + align:start position:0% +undergoes all these possible decay +mechanisms glad no one's saying anything + + align:start position:0% +mechanisms glad no one's saying anything + + + align:start position:0% +mechanisms glad no one's saying anything +because neither have I there's one that + + align:start position:0% +because neither have I there's one that + + + align:start position:0% +because neither have I there's one that +comes close actually if you look at no + + align:start position:0% +comes close actually if you look at no + + + align:start position:0% +comes close actually if you look at no +that's not this part I want to show you + + align:start position:0% +that's not this part I want to show you + + + align:start position:0% +that's not this part I want to show you +I want to show you the big one if you + + align:start position:0% +I want to show you the big one if you + + + align:start position:0% +I want to show you the big one if you +look at potassium-40 the nuclide we've + + align:start position:0% +look at potassium-40 the nuclide we've + + + align:start position:0% +look at potassium-40 the nuclide we've +probably talked about the most so far it + + align:start position:0% +probably talked about the most so far it + + + align:start position:0% +probably talked about the most so far it +covers most of the space of this + + align:start position:0% +covers most of the space of this + + + align:start position:0% +covers most of the space of this +generalized a.k diagram and there was a + + align:start position:0% +generalized a.k diagram and there was a + + + align:start position:0% +generalized a.k diagram and there was a +question that came through at least I + + align:start position:0% +question that came through at least I + + + align:start position:0% +question that came through at least I +think or non-anonymous email what is it + + align:start position:0% +think or non-anonymous email what is it + + + align:start position:0% +think or non-anonymous email what is it +that makes these even even versus + + align:start position:0% +that makes these even even versus + + + align:start position:0% +that makes these even even versus +odd-odd nuclei less or more stable + + align:start position:0% +odd-odd nuclei less or more stable + + + align:start position:0% +odd-odd nuclei less or more stable +anytime you have an odd odd nucleus both + + align:start position:0% +anytime you have an odd odd nucleus both + + + align:start position:0% +anytime you have an odd odd nucleus both +the number of protons the number of + + align:start position:0% +the number of protons the number of + + + align:start position:0% +the number of protons the number of +neutrons these nuclear shells are not + + align:start position:0% +neutrons these nuclear shells are not + + + align:start position:0% +neutrons these nuclear shells are not +fully occupied and they're not that + + align:start position:0% +fully occupied and they're not that + + + align:start position:0% +fully occupied and they're not that +stable compared to an even even nucleus + + align:start position:0% +stable compared to an even even nucleus + + + align:start position:0% +stable compared to an even even nucleus +that has an even number of Z and an even + + align:start position:0% +that has an even number of Z and an even + + + align:start position:0% +that has an even number of Z and an even +number of n just kind of like electrons + + align:start position:0% +number of n just kind of like electrons + + + align:start position:0% +number of n just kind of like electrons +these things tend to travel in pairs and + + align:start position:0% +these things tend to travel in pairs and + + + align:start position:0% +these things tend to travel in pairs and +not fully occupied energy levels will be + + align:start position:0% +not fully occupied energy levels will be + + + align:start position:0% +not fully occupied energy levels will be +less stable potassium-40 happens to be + + align:start position:0% +less stable potassium-40 happens to be + + + align:start position:0% +less stable potassium-40 happens to be +one of those odd-odd nuclei that is + + align:start position:0% +one of those odd-odd nuclei that is + + + align:start position:0% +one of those odd-odd nuclei that is +relatively unstable and it can go either + + align:start position:0% +relatively unstable and it can go either + + + align:start position:0% +relatively unstable and it can go either +way either you can lose a proton or you + + align:start position:0% +way either you can lose a proton or you + + + align:start position:0% +way either you can lose a proton or you +can gain a proton by competing + + align:start position:0% +can gain a proton by competing + + + align:start position:0% +can gain a proton by competing +mechanisms like positron or electron + + align:start position:0% +mechanisms like positron or electron + + + align:start position:0% +mechanisms like positron or electron +capture + + align:start position:0% +capture + + + align:start position:0% +capture +or beta emission so this one I like a + + align:start position:0% +or beta emission so this one I like a + + + align:start position:0% +or beta emission so this one I like a +lot because it gives you almost every + + align:start position:0% +lot because it gives you almost every + + + align:start position:0% +lot because it gives you almost every +possible decay with the exception of + + align:start position:0% +possible decay with the exception of + + + align:start position:0% +possible decay with the exception of +alpha decay and spontaneous Neutron + + align:start position:0% +alpha decay and spontaneous Neutron + + + align:start position:0% +alpha decay and spontaneous Neutron +emission it's not that unstable and you + + align:start position:0% +emission it's not that unstable and you + + + align:start position:0% +emission it's not that unstable and you +know only one really missing from here I + + align:start position:0% +know only one really missing from here I + + + align:start position:0% +know only one really missing from here I +found what I think is the simplest to K + + align:start position:0% +found what I think is the simplest to K + + + align:start position:0% +found what I think is the simplest to K +diagram ever just prozium 151 there's + + align:start position:0% +diagram ever just prozium 151 there's + + + align:start position:0% +diagram ever just prozium 151 there's +only one thing it can do is it can decay + + align:start position:0% +only one thing it can do is it can decay + + + align:start position:0% +only one thing it can do is it can decay +via alpha decay to its ground state I + + align:start position:0% +via alpha decay to its ground state I + + + align:start position:0% +via alpha decay to its ground state I +want to point out a few of the features + + align:start position:0% +want to point out a few of the features + + + align:start position:0% +want to point out a few of the features +of these decay diagrams so you know what + + align:start position:0% +of these decay diagrams so you know what + + + align:start position:0% +of these decay diagrams so you know what +to look for up here is the parent + + align:start position:0% +to look for up here is the parent + + + align:start position:0% +to look for up here is the parent +nucleus down there's the daughter + + align:start position:0% +nucleus down there's the daughter + + + align:start position:0% +nucleus down there's the daughter +nucleus and these energies are not + + align:start position:0% +nucleus and these energies are not + + + align:start position:0% +nucleus and these energies are not +absolute they're relative to the ground + + align:start position:0% +absolute they're relative to the ground + + + align:start position:0% +absolute they're relative to the ground +state of whatever the daughter nucleus + + align:start position:0% +state of whatever the daughter nucleus + + + align:start position:0% +state of whatever the daughter nucleus +is so this is a simple example who helps + + align:start position:0% +is so this is a simple example who helps + + + align:start position:0% +is so this is a simple example who helps +show you that Galilean 147 doesn't have + + align:start position:0% +show you that Galilean 147 doesn't have + + + align:start position:0% +show you that Galilean 147 doesn't have +a binding energy of zero this is + + align:start position:0% +a binding energy of zero this is + + + align:start position:0% +a binding energy of zero this is +relative to the ground state of Gadd 147 + + align:start position:0% +relative to the ground state of Gadd 147 + + + align:start position:0% +relative to the ground state of Gadd 147 +and that will tell you that the Q value + + align:start position:0% +and that will tell you that the Q value + + + align:start position:0% +and that will tell you that the Q value +for this reaction is 4.1 796 MeV these + + align:start position:0% +for this reaction is 4.1 796 MeV these + + + align:start position:0% +for this reaction is 4.1 796 MeV these +things are usually listed in MeV unless + + align:start position:0% +things are usually listed in MeV unless + + + align:start position:0% +things are usually listed in MeV unless +said otherwise you also might notice a + + align:start position:0% +said otherwise you also might notice a + + + align:start position:0% +said otherwise you also might notice a +pattern that most alpha particles tend + + align:start position:0% +pattern that most alpha particles tend + + + align:start position:0% +pattern that most alpha particles tend +to come out around 4 MeV or larger the + + align:start position:0% +to come out around 4 MeV or larger the + + + align:start position:0% +to come out around 4 MeV or larger the +answer to y is going to be given in 2202 + + align:start position:0% +answer to y is going to be given in 2202 + + + align:start position:0% +answer to y is going to be given in 2202 +yep these percentages tell you the + + align:start position:0% +yep these percentages tell you the + + + align:start position:0% +yep these percentages tell you the +probability that each decay will happen + + align:start position:0% + + + + align:start position:0% + +these are usually measured because it + + align:start position:0% +these are usually measured because it + + + align:start position:0% +these are usually measured because it +can be let's say let's say things get + + align:start position:0% +can be let's say let's say things get + + + align:start position:0% +can be let's say let's say things get +quantum and difficult in terms of + + align:start position:0% +quantum and difficult in terms of + + + align:start position:0% +quantum and difficult in terms of +calculating these and our knowledge of + + align:start position:0% +calculating these and our knowledge of + + + align:start position:0% +calculating these and our knowledge of +wave functions of well higher and higher + + align:start position:0% +wave functions of well higher and higher + + + align:start position:0% +wave functions of well higher and higher +a or Z nuclei gets a little less time a + + align:start position:0% +a or Z nuclei gets a little less time a + + + align:start position:0% +a or Z nuclei gets a little less time a +little more tenuous so a lot of these + + align:start position:0% +little more tenuous so a lot of these + + + align:start position:0% +little more tenuous so a lot of these +would be measured you can look at the + + align:start position:0% +would be measured you can look at the + + + align:start position:0% +would be measured you can look at the +number of alpha particles of each energy + + align:start position:0% +number of alpha particles of each energy + + + align:start position:0% +number of alpha particles of each energy +that you observe and then you get the + + align:start position:0% +that you observe and then you get the + + + align:start position:0% +that you observe and then you get the +average probabilities for this one it's + + align:start position:0% +average probabilities for this one it's + + + align:start position:0% +average probabilities for this one it's +simple there's a hundred percent + + align:start position:0% +simple there's a hundred percent + + + align:start position:0% +simple there's a hundred percent +probability that this is the only thing + + align:start position:0% +probability that this is the only thing + + + align:start position:0% +probability that this is the only thing +that exists the other things to note the + + align:start position:0% +that exists the other things to note the + + + align:start position:0% +that exists the other things to note the +half-life will be given up here in this + + align:start position:0% +half-life will be given up here in this + + + align:start position:0% +half-life will be given up here in this +case at seventeen point nine minutes so + + align:start position:0% +case at seventeen point nine minutes so + + + align:start position:0% +case at seventeen point nine minutes so +relatively long half-life compared to + + align:start position:0% +relatively long half-life compared to + + + align:start position:0% +relatively long half-life compared to +helium five and we'll be going over what + + align:start position:0% +helium five and we'll be going over what + + + align:start position:0% +helium five and we'll be going over what +half-life is and what they are on Friday + + align:start position:0% +half-life is and what they are on Friday + + + align:start position:0% +half-life is and what they are on Friday +and then the last thing are the spin + + align:start position:0% +and then the last thing are the spin + + + align:start position:0% +and then the last thing are the spin +states of the initial and final nuclei + + align:start position:0% +states of the initial and final nuclei + + + align:start position:0% +states of the initial and final nuclei +which we will not cover in this class + + align:start position:0% +which we will not cover in this class + + + align:start position:0% +which we will not cover in this class +but you will cover in 22:02 so + + align:start position:0% +but you will cover in 22:02 so + + + align:start position:0% +but you will cover in 22:02 so +don't worry about those now but do know + + align:start position:0% +don't worry about those now but do know + + + align:start position:0% +don't worry about those now but do know +that when you need to go find the spin + + align:start position:0% +that when you need to go find the spin + + + align:start position:0% +that when you need to go find the spin +states of the initial and final nuclei + + align:start position:0% +states of the initial and final nuclei + + + align:start position:0% +states of the initial and final nuclei +to see if certain transitions are + + align:start position:0% +to see if certain transitions are + + + align:start position:0% +to see if certain transitions are +allowed this is where you're going to go + + align:start position:0% +allowed this is where you're going to go + + + align:start position:0% +allowed this is where you're going to go +any questions on what you see here on + + align:start position:0% +any questions on what you see here on + + + align:start position:0% +any questions on what you see here on +how to read these decay diagrams okay + + align:start position:0% +how to read these decay diagrams okay + + + align:start position:0% +how to read these decay diagrams okay +then let's move on to some the simplest + + align:start position:0% +then let's move on to some the simplest + + + align:start position:0% +then let's move on to some the simplest +of them which in the table can look the + + align:start position:0% +of them which in the table can look the + + + align:start position:0% +of them which in the table can look the +most complicated so here you can see + + align:start position:0% +most complicated so here you can see + + + align:start position:0% +most complicated so here you can see +that there's a whole bunch of different + + align:start position:0% +that there's a whole bunch of different + + + align:start position:0% +that there's a whole bunch of different +probabilities for different alpha decay + + align:start position:0% +probabilities for different alpha decay + + + align:start position:0% +probabilities for different alpha decay +nuclear this is one of those more + + align:start position:0% +nuclear this is one of those more + + + align:start position:0% +nuclear this is one of those more +complex examples where the easiest thing + + align:start position:0% +complex examples where the easiest thing + + + align:start position:0% +complex examples where the easiest thing +to do is just measure see how many + + align:start position:0% +to do is just measure see how many + + + align:start position:0% +to do is just measure see how many +alphas you get at each energy and this + + align:start position:0% +alphas you get at each energy and this + + + align:start position:0% +alphas you get at each energy and this +will give you the approximate + + align:start position:0% +will give you the approximate + + + align:start position:0% +will give you the approximate +probabilities that each decay happens + + align:start position:0% +probabilities that each decay happens + + + align:start position:0% +probabilities that each decay happens +and you'll notice here that the final + + align:start position:0% +and you'll notice here that the final + + + align:start position:0% +and you'll notice here that the final +energy states for each of these alphas + + align:start position:0% +energy states for each of these alphas + + + align:start position:0% +energy states for each of these alphas +is not necessarily zero this will tell + + align:start position:0% +is not necessarily zero this will tell + + + align:start position:0% +is not necessarily zero this will tell +you what they are relative to the ground + + align:start position:0% +you what they are relative to the ground + + + align:start position:0% +you what they are relative to the ground +state of in this case thorium 231 so you + + align:start position:0% +state of in this case thorium 231 so you + + + align:start position:0% +state of in this case thorium 231 so you +can emit an alpha from from any + + align:start position:0% +can emit an alpha from from any + + + align:start position:0% +can emit an alpha from from any +combination of nuclear shell levels + + align:start position:0% +combination of nuclear shell levels + + + align:start position:0% +combination of nuclear shell levels +inside this nucleus and you might end up + + align:start position:0% +inside this nucleus and you might end up + + + align:start position:0% +inside this nucleus and you might end up +with a new daughter nucleus whose + + align:start position:0% +with a new daughter nucleus whose + + + align:start position:0% +with a new daughter nucleus whose +protons or neutrons are in excited + + align:start position:0% +protons or neutrons are in excited + + + align:start position:0% +protons or neutrons are in excited +States and the way you remove those + + align:start position:0% +States and the way you remove those + + + align:start position:0% +States and the way you remove those +excited States is gamma decay like we + + align:start position:0% +excited States is gamma decay like we + + + align:start position:0% +excited States is gamma decay like we +talked about here so a lot of alpha + + align:start position:0% +talked about here so a lot of alpha + + + align:start position:0% +talked about here so a lot of alpha +decays are immediately followed by a + + align:start position:0% +decays are immediately followed by a + + + align:start position:0% +decays are immediately followed by a +chain of gamma decays or what we call I + + align:start position:0% +chain of gamma decays or what we call I + + + align:start position:0% +chain of gamma decays or what we call I +teased or isomeric transitions so you'll + + align:start position:0% +teased or isomeric transitions so you'll + + + align:start position:0% +teased or isomeric transitions so you'll +see a couple bits of notation for + + align:start position:0% +see a couple bits of notation for + + + align:start position:0% +see a couple bits of notation for +example you make here called gamma decay + + align:start position:0% +example you make here called gamma decay + + + align:start position:0% +example you make here called gamma decay +you may hear it called isomeric + + align:start position:0% +you may hear it called isomeric + + + align:start position:0% +you may hear it called isomeric +transition we'll try to give them all so + + align:start position:0% +transition we'll try to give them all so + + + align:start position:0% +transition we'll try to give them all so +that in the various readings you have + + align:start position:0% +that in the various readings you have + + + align:start position:0% +that in the various readings you have +you know what's what so notice here you + + align:start position:0% +you know what's what so notice here you + + + align:start position:0% +you know what's what so notice here you +can have with the probability still + + align:start position:0% +can have with the probability still + + + align:start position:0% +can have with the probability still +small that they didn't bother to draw it + + align:start position:0% +small that they didn't bother to draw it + + + align:start position:0% +small that they didn't bother to draw it +an alpha decay to 0.6 3 4 MeV and then + + align:start position:0% +an alpha decay to 0.6 3 4 MeV and then + + + align:start position:0% +an alpha decay to 0.6 3 4 MeV and then +any series of gammas from let's say from + + align:start position:0% +any series of gammas from let's say from + + + align:start position:0% +any series of gammas from let's say from +this state to that state and then from + + align:start position:0% +this state to that state and then from + + + align:start position:0% +this state to that state and then from +this state to one of those or one of + + align:start position:0% +this state to one of those or one of + + + align:start position:0% +this state to one of those or one of +those and then another one down there so + + align:start position:0% +those and then another one down there so + + + align:start position:0% +those and then another one down there so +an alpha decay may be followed by a + + align:start position:0% +an alpha decay may be followed by a + + + align:start position:0% +an alpha decay may be followed by a +whole bunch of gamma transitions or as + + align:start position:0% +whole bunch of gamma transitions or as + + + align:start position:0% +whole bunch of gamma transitions or as +few as none if you want to see what the + + align:start position:0% +few as none if you want to see what the + + + align:start position:0% +few as none if you want to see what the +Alpha energies are well let's head to + + align:start position:0% +Alpha energies are well let's head to + + + align:start position:0% +Alpha energies are well let's head to +the table of nuclides and look at + + align:start position:0% +the table of nuclides and look at + + + align:start position:0% +the table of nuclides and look at +uranium-235 + + align:start position:0% + + + + align:start position:0% + +so if we look up u-235 you can see that + + align:start position:0% +so if we look up u-235 you can see that + + + align:start position:0% +so if we look up u-235 you can see that +at alpha decays to thorium 231 and I'll + + align:start position:0% +at alpha decays to thorium 231 and I'll + + + align:start position:0% +at alpha decays to thorium 231 and I'll +show you the part of the table that I + + align:start position:0% +show you the part of the table that I + + + align:start position:0% +show you the part of the table that I +didn't show you in the slides which is + + align:start position:0% +didn't show you in the slides which is + + + align:start position:0% +didn't show you in the slides which is +then you've got a table of alpha decay + + align:start position:0% +then you've got a table of alpha decay + + + align:start position:0% +then you've got a table of alpha decay +energies as well as relative intensities + + align:start position:0% +energies as well as relative intensities + + + align:start position:0% +energies as well as relative intensities +and what's called a hindrance this stuff + + align:start position:0% +and what's called a hindrance this stuff + + + align:start position:0% +and what's called a hindrance this stuff +right here comes from the fact that + + align:start position:0% +right here comes from the fact that + + + align:start position:0% +right here comes from the fact that +different alpha decay energies can + + align:start position:0% +different alpha decay energies can + + + align:start position:0% +different alpha decay energies can +happen with different probabilities at + + align:start position:0% +happen with different probabilities at + + + align:start position:0% +happen with different probabilities at +different times so the half-life of a + + align:start position:0% +different times so the half-life of a + + + align:start position:0% +different times so the half-life of a +particular alpha decay can be slightly + + align:start position:0% +particular alpha decay can be slightly + + + align:start position:0% +particular alpha decay can be slightly +different and this is another one of + + align:start position:0% +different and this is another one of + + + align:start position:0% +different and this is another one of +those really kooky things where certain + + align:start position:0% +those really kooky things where certain + + + align:start position:0% +those really kooky things where certain +energy alpha transitions will happen a + + align:start position:0% +energy alpha transitions will happen a + + + align:start position:0% +energy alpha transitions will happen a +little more often initially then finally + + align:start position:0% +little more often initially then finally + + + align:start position:0% +little more often initially then finally +but we don't have to worry about that + + align:start position:0% +but we don't have to worry about that + + + align:start position:0% +but we don't have to worry about that +yet I just want you to know that's why + + align:start position:0% +yet I just want you to know that's why + + + align:start position:0% +yet I just want you to know that's why +the hindrance is there and so you can + + align:start position:0% +the hindrance is there and so you can + + + align:start position:0% +the hindrance is there and so you can +look from this table what's the + + align:start position:0% +look from this table what's the + + + align:start position:0% +look from this table what's the +probability that each of these alphas + + align:start position:0% +probability that each of these alphas + + + align:start position:0% +probability that each of these alphas +will come out and there's going to be + + align:start position:0% +will come out and there's going to be + + + align:start position:0% +will come out and there's going to be +some uncertainty associated with these + + align:start position:0% +some uncertainty associated with these + + + align:start position:0% +some uncertainty associated with these +this is going to usually be some sort of + + align:start position:0% +this is going to usually be some sort of + + + align:start position:0% +this is going to usually be some sort of +measurement uncertainty then you might + + align:start position:0% +measurement uncertainty then you might + + + align:start position:0% +measurement uncertainty then you might +also ask why is it that the highest + + align:start position:0% +also ask why is it that the highest + + + align:start position:0% +also ask why is it that the highest +energy alpha ray is not the same energy + + align:start position:0% +energy alpha ray is not the same energy + + + align:start position:0% +energy alpha ray is not the same energy +as the Q value so for this + + align:start position:0% +as the Q value so for this + + + align:start position:0% +as the Q value so for this +it's a greatly simplified application of + + align:start position:0% +it's a greatly simplified application of + + + align:start position:0% +it's a greatly simplified application of +the Q equation that we learned last time + + align:start position:0% +the Q equation that we learned last time + + + align:start position:0% +the Q equation that we learned last time +so for here what are the two equations + + align:start position:0% +so for here what are the two equations + + + align:start position:0% +so for here what are the two equations +that we need to conserve if we have a + + align:start position:0% +that we need to conserve if we have a + + + align:start position:0% +that we need to conserve if we have a +system consisting of we have our initial + + align:start position:0% +system consisting of we have our initial + + + align:start position:0% +system consisting of we have our initial +nuclei going into our final nuclei and + + align:start position:0% +nuclei going into our final nuclei and + + + align:start position:0% +nuclei going into our final nuclei and +they go off in equal and opposite + + align:start position:0% +they go off in equal and opposite + + + align:start position:0% +they go off in equal and opposite +directions if it's alpha decay then we + + align:start position:0% +directions if it's alpha decay then we + + + align:start position:0% +directions if it's alpha decay then we +have no little initial nucleus we just + + align:start position:0% +have no little initial nucleus we just + + + align:start position:0% +have no little initial nucleus we just +had a large initial nucleus at last at + + align:start position:0% +had a large initial nucleus at last at + + + align:start position:0% +had a large initial nucleus at last at +rest and afterwards you've got a small + + align:start position:0% +rest and afterwards you've got a small + + + align:start position:0% +rest and afterwards you've got a small +final nucleus which we know is the alpha + + align:start position:0% +final nucleus which we know is the alpha + + + align:start position:0% +final nucleus which we know is the alpha +particle and a large final nucleus which + + align:start position:0% +particle and a large final nucleus which + + + align:start position:0% +particle and a large final nucleus which +we'll call the daughter product and + + align:start position:0% +we'll call the daughter product and + + + align:start position:0% +we'll call the daughter product and +let's say this is the parent it's a much + + align:start position:0% +let's say this is the parent it's a much + + + align:start position:0% +let's say this is the parent it's a much +much simpler system than the general one + + align:start position:0% +much simpler system than the general one + + + align:start position:0% +much simpler system than the general one +we analyzed last week so what are the + + align:start position:0% +we analyzed last week so what are the + + + align:start position:0% +we analyzed last week so what are the +equations that will use to conserve to + + align:start position:0% +equations that will use to conserve to + + + align:start position:0% +equations that will use to conserve to +find out what's the energy of this alpha + + align:start position:0% +find out what's the energy of this alpha + + + align:start position:0% +find out what's the energy of this alpha +particle anyone same three answers as + + align:start position:0% +particle anyone same three answers as + + + align:start position:0% +particle anyone same three answers as +always yep yep mass energy and momentum + + align:start position:0% + + + + align:start position:0% + +I'm gonna lump these two together + + align:start position:0% +I'm gonna lump these two together + + + align:start position:0% +I'm gonna lump these two together +because they're kind of the same thing + + align:start position:0% +because they're kind of the same thing + + + align:start position:0% +because they're kind of the same thing +so let's just go with energy and + + align:start position:0% +so let's just go with energy and + + + align:start position:0% +so let's just go with energy and +momentum so what is the initial kinetic + + align:start position:0% +momentum so what is the initial kinetic + + + align:start position:0% +momentum so what is the initial kinetic +energy or let's say the initial kinetic + + align:start position:0% +energy or let's say the initial kinetic + + + align:start position:0% +energy or let's say the initial kinetic +energy of this parent nucleus we can + + align:start position:0% +energy of this parent nucleus we can + + + align:start position:0% +energy of this parent nucleus we can +assume to be zero + + align:start position:0% +assume to be zero + + + align:start position:0% +assume to be zero +what about the final kinetic energy of + + align:start position:0% +what about the final kinetic energy of + + + align:start position:0% +what about the final kinetic energy of +the system well there's only two + + align:start position:0% +the system well there's only two + + + align:start position:0% +the system well there's only two +particles there's going to be some + + align:start position:0% +particles there's going to be some + + + align:start position:0% +particles there's going to be some +kinetic energy of the alpha particle + + align:start position:0% +kinetic energy of the alpha particle + + + align:start position:0% +kinetic energy of the alpha particle +plus the recoiled kinetic energy because + + align:start position:0% +plus the recoiled kinetic energy because + + + align:start position:0% +plus the recoiled kinetic energy because +if the alpha goes in one direction the + + align:start position:0% +if the alpha goes in one direction the + + + align:start position:0% +if the alpha goes in one direction the +daughter nucleus has to go off in the + + align:start position:0% +daughter nucleus has to go off in the + + + align:start position:0% +daughter nucleus has to go off in the +other direction and the total energy + + align:start position:0% +other direction and the total energy + + + align:start position:0% +other direction and the total energy +comes out to Q this Q value you can get + + align:start position:0% +comes out to Q this Q value you can get + + + align:start position:0% +comes out to Q this Q value you can get +by conserving Nath's where we can say + + align:start position:0% +by conserving Nath's where we can say + + + align:start position:0% +by conserving Nath's where we can say +that the mass of the parent has to equal + + align:start position:0% +that the mass of the parent has to equal + + + align:start position:0% +that the mass of the parent has to equal +the mass of the Alpha plus the mass of + + align:start position:0% +the mass of the Alpha plus the mass of + + + align:start position:0% +the mass of the Alpha plus the mass of +the daughter plus Q + + align:start position:0% + + + + align:start position:0% + +so that's where we can get cute if we + + align:start position:0% +so that's where we can get cute if we + + + align:start position:0% +so that's where we can get cute if we +don't know it already luckily we know it + + align:start position:0% +don't know it already luckily we know it + + + align:start position:0% +don't know it already luckily we know it +already so there we've used mass there + + align:start position:0% +already so there we've used mass there + + + align:start position:0% +already so there we've used mass there +we've used energy and now what are the + + align:start position:0% +we've used energy and now what are the + + + align:start position:0% +we've used energy and now what are the +momentum of the initial and final states + + align:start position:0% +momentum of the initial and final states + + + align:start position:0% +momentum of the initial and final states +here anyone just shout it out what's the + + align:start position:0% +here anyone just shout it out what's the + + + align:start position:0% +here anyone just shout it out what's the +initial momentum of the parent nucleus + + align:start position:0% +initial momentum of the parent nucleus + + + align:start position:0% +initial momentum of the parent nucleus +zero equals what's the momentum of the + + align:start position:0% +zero equals what's the momentum of the + + + align:start position:0% +zero equals what's the momentum of the +Alpha and then remember that trick if we + + align:start position:0% +Alpha and then remember that trick if we + + + align:start position:0% +Alpha and then remember that trick if we +want to say p equals MV equals what more + + align:start position:0% +want to say p equals MV equals what more + + + align:start position:0% +want to say p equals MV equals what more +convenient form that contains the energy + + align:start position:0% + + + + align:start position:0% + +square root of 2m t so let's go with + + align:start position:0% +square root of 2m t so let's go with + + + align:start position:0% +square root of 2m t so let's go with +that so there'll be the square root of + + align:start position:0% +that so there'll be the square root of + + + align:start position:0% +that so there'll be the square root of +two mass of the Alpha kinetic energy of + + align:start position:0% +two mass of the Alpha kinetic energy of + + + align:start position:0% +two mass of the Alpha kinetic energy of +the Alpha minus the square root of two + + align:start position:0% +the Alpha minus the square root of two + + + align:start position:0% +the Alpha minus the square root of two +times the mass of the daughter times the + + align:start position:0% +times the mass of the daughter times the + + + align:start position:0% +times the mass of the daughter times the +kinetic energy of the daughter because + + align:start position:0% +kinetic energy of the daughter because + + + align:start position:0% +kinetic energy of the daughter because +these have to have equal and opposite + + align:start position:0% +these have to have equal and opposite + + + align:start position:0% +these have to have equal and opposite +momentum so all we have to do is move + + align:start position:0% +momentum so all we have to do is move + + + align:start position:0% +momentum so all we have to do is move +that one over here this makes that + + align:start position:0% +that one over here this makes that + + + align:start position:0% +that one over here this makes that +equation easy everything's got a square + + align:start position:0% +equation easy everything's got a square + + + align:start position:0% +equation easy everything's got a square +root of two we can square both sides and + + align:start position:0% +root of two we can square both sides and + + + align:start position:0% +root of two we can square both sides and +we end up with a pretty simple relation + + align:start position:0% +we end up with a pretty simple relation + + + align:start position:0% +we end up with a pretty simple relation +mass of the alpha times the kinetic + + align:start position:0% +mass of the alpha times the kinetic + + + align:start position:0% +mass of the alpha times the kinetic +energy of the Alpha is the mass of the + + align:start position:0% +energy of the Alpha is the mass of the + + + align:start position:0% +energy of the Alpha is the mass of the +daughter times the kinetic energy of the + + align:start position:0% +daughter times the kinetic energy of the + + + align:start position:0% +daughter times the kinetic energy of the +daughter we don't usually care about the + + align:start position:0% +daughter we don't usually care about the + + + align:start position:0% +daughter we don't usually care about the +kinetic energy of the recoil nucleus or + + align:start position:0% +kinetic energy of the recoil nucleus or + + + align:start position:0% +kinetic energy of the recoil nucleus or +the daughter because the range is so + + align:start position:0% +the daughter because the range is so + + + align:start position:0% +the daughter because the range is so +small that we usually don't get to + + align:start position:0% +small that we usually don't get to + + + align:start position:0% +small that we usually don't get to +measure it but we are trying to measure + + align:start position:0% +measure it but we are trying to measure + + + align:start position:0% +measure it but we are trying to measure +what are the actual alpha particle + + align:start position:0% +what are the actual alpha particle + + + align:start position:0% +what are the actual alpha particle +energies so that we can reconstruct oops + + align:start position:0% +energies so that we can reconstruct oops + + + align:start position:0% +energies so that we can reconstruct oops +this table down here so we can take our + + align:start position:0% +this table down here so we can take our + + + align:start position:0% +this table down here so we can take our +energy conservation equation and + + align:start position:0% +energy conservation equation and + + + align:start position:0% +energy conservation equation and +rearrange it to isolate TD the kinetic + + align:start position:0% +rearrange it to isolate TD the kinetic + + + align:start position:0% +rearrange it to isolate TD the kinetic +energy of the daughter and say TD equals + + align:start position:0% +energy of the daughter and say TD equals + + + align:start position:0% +energy of the daughter and say TD equals +Q minus T alpha substitute that in here + + align:start position:0% +Q minus T alpha substitute that in here + + + align:start position:0% +Q minus T alpha substitute that in here +and let's rewrite what we've got mass of + + align:start position:0% +and let's rewrite what we've got mass of + + + align:start position:0% +and let's rewrite what we've got mass of +the alpha T alpha equals mass of the + + align:start position:0% +the alpha T alpha equals mass of the + + + align:start position:0% +the alpha T alpha equals mass of the +daughter times + + align:start position:0% +daughter times + + + align:start position:0% +daughter times +Q minus T alpha if we multiply each term + + align:start position:0% +Q minus T alpha if we multiply each term + + + align:start position:0% +Q minus T alpha if we multiply each term +in here by M D we get M DQ minus M D T + + align:start position:0% +in here by M D we get M DQ minus M D T + + + align:start position:0% +in here by M D we get M DQ minus M D T +alpha then we can take all of the T + + align:start position:0% +alpha then we can take all of the T + + + align:start position:0% +alpha then we can take all of the T +alphas on one side so we'll just add T I + + align:start position:0% +alphas on one side so we'll just add T I + + + align:start position:0% +alphas on one side so we'll just add T I +add M DT alpha to each side so we have M + + align:start position:0% +add M DT alpha to each side so we have M + + + align:start position:0% +add M DT alpha to each side so we have M +alpha T alpha plus M DT alpha equals M + + align:start position:0% +alpha T alpha plus M DT alpha equals M + + + align:start position:0% +alpha T alpha plus M DT alpha equals M +DQ we can factor out the T alpha here + + align:start position:0% +DQ we can factor out the T alpha here + + + align:start position:0% +DQ we can factor out the T alpha here +and then we can divide each side by M + + align:start position:0% +and then we can divide each side by M + + + align:start position:0% +and then we can divide each side by M +alpha plus M daughter cancel out the MA + + align:start position:0% +alpha plus M daughter cancel out the MA + + + align:start position:0% +alpha plus M daughter cancel out the MA +plus M D and there we have the answer + + align:start position:0% +plus M D and there we have the answer + + + align:start position:0% +plus M D and there we have the answer +the kinetic energy alpha is just the Q + + align:start position:0% +the kinetic energy alpha is just the Q + + + align:start position:0% +the kinetic energy alpha is just the Q +value times the ratio of the daughter + + align:start position:0% +value times the ratio of the daughter + + + align:start position:0% +value times the ratio of the daughter +mass to the total mass this should look + + align:start position:0% +mass to the total mass this should look + + + align:start position:0% +mass to the total mass this should look +awfully familiar when we did this in the + + align:start position:0% +awfully familiar when we did this in the + + + align:start position:0% +awfully familiar when we did this in the +frame of Neutron elastic scattering or + + align:start position:0% +frame of Neutron elastic scattering or + + + align:start position:0% +frame of Neutron elastic scattering or +any other reaction we had the same + + align:start position:0% +any other reaction we had the same + + + align:start position:0% +any other reaction we had the same +equation with just different notation so + + align:start position:0% +equation with just different notation so + + + align:start position:0% +equation with just different notation so +do you guys recognize this firmware we + + align:start position:0% +do you guys recognize this firmware we + + + align:start position:0% +do you guys recognize this firmware we +had t3 equals Q times M 4 over m 3 plus + + align:start position:0% +had t3 equals Q times M 4 over m 3 plus + + + align:start position:0% +had t3 equals Q times M 4 over m 3 plus +M 4 it's the exact same result just + + align:start position:0% +M 4 it's the exact same result just + + + align:start position:0% +M 4 it's the exact same result just +different notation last time we did it + + align:start position:0% +different notation last time we did it + + + align:start position:0% +different notation last time we did it +in the most complex way possible this + + align:start position:0% +in the most complex way possible this + + + align:start position:0% +in the most complex way possible this +time we started off with the simplest + + align:start position:0% +time we started off with the simplest + + + align:start position:0% +time we started off with the simplest +possible equations for alpha decay in + + align:start position:0% +possible equations for alpha decay in + + + align:start position:0% +possible equations for alpha decay in +the end it's the same q equation we just + + align:start position:0% +the end it's the same q equation we just + + + align:start position:0% +the end it's the same q equation we just +didn't bother what all the other terms + + align:start position:0% +didn't bother what all the other terms + + + align:start position:0% +didn't bother what all the other terms +and angles and things that we don't need + + align:start position:0% +and angles and things that we don't need + + + align:start position:0% +and angles and things that we don't need +so is everyone clear where this came + + align:start position:0% +so is everyone clear where this came + + + align:start position:0% +so is everyone clear where this came +from cool and that's why you're never + + align:start position:0% +from cool and that's why you're never + + + align:start position:0% +from cool and that's why you're never +going to see an alpha particle that's + + align:start position:0% +going to see an alpha particle that's + + + align:start position:0% +going to see an alpha particle that's +got the same energy as the initial minus + + align:start position:0% +got the same energy as the initial minus + + + align:start position:0% +got the same energy as the initial minus +the final energy because the recoil + + align:start position:0% +the final energy because the recoil + + + align:start position:0% +the final energy because the recoil +nucleus or the daughter nucleus takes + + align:start position:0% +nucleus or the daughter nucleus takes + + + align:start position:0% +nucleus or the daughter nucleus takes +away some of that kinetic energy in + + align:start position:0% +away some of that kinetic energy in + + + align:start position:0% +away some of that kinetic energy in +order to conserve the momentum of the + + align:start position:0% +order to conserve the momentum of the + + + align:start position:0% +order to conserve the momentum of the +system that was initially at rest + + align:start position:0% +system that was initially at rest + + + align:start position:0% +system that was initially at rest +another way to say this for those who + + align:start position:0% +another way to say this for those who + + + align:start position:0% +another way to say this for those who +like center of mass coordinates is the + + align:start position:0% +like center of mass coordinates is the + + + align:start position:0% +like center of mass coordinates is the +center of mass of this system was + + align:start position:0% +center of mass of this system was + + + align:start position:0% +center of mass of this system was +the parent nucleus it was at rest the + + align:start position:0% +the parent nucleus it was at rest the + + + align:start position:0% +the parent nucleus it was at rest the +center of mass of the final system has + + align:start position:0% +center of mass of the final system has + + + align:start position:0% +center of mass of the final system has +to remain at rest to conserve momentum + + align:start position:0% +to remain at rest to conserve momentum + + + align:start position:0% +to remain at rest to conserve momentum +but again I won't go into much into + + align:start position:0% +but again I won't go into much into + + + align:start position:0% +but again I won't go into much into +center of mass because I find it a + + align:start position:0% +center of mass because I find it a + + + align:start position:0% +center of mass because I find it a +little unintuitive + + align:start position:0% +little unintuitive + + + align:start position:0% +little unintuitive +I'll stick with a laboratory frame of + + align:start position:0% +I'll stick with a laboratory frame of + + + align:start position:0% +I'll stick with a laboratory frame of +reference so any questions before I move + + align:start position:0% +reference so any questions before I move + + + align:start position:0% +reference so any questions before I move +on alpha I think is the simplest case of + + align:start position:0% +on alpha I think is the simplest case of + + + align:start position:0% +on alpha I think is the simplest case of +radioactive decay and think now you know + + align:start position:0% +radioactive decay and think now you know + + + align:start position:0% +radioactive decay and think now you know +all you need to know about it yes they + + align:start position:0% +all you need to know about it yes they + + + align:start position:0% +all you need to know about it yes they +were not not MA and MD but TA and TD + + align:start position:0% +were not not MA and MD but TA and TD + + + align:start position:0% +were not not MA and MD but TA and TD +would change yep so in this case for a + + align:start position:0% +would change yep so in this case for a + + + align:start position:0% +would change yep so in this case for a +different alpha decays they'll have + + align:start position:0% +different alpha decays they'll have + + + align:start position:0% +different alpha decays they'll have +different Q values so the Q value of + + align:start position:0% +different Q values so the Q value of + + + align:start position:0% +different Q values so the Q value of +let's say this top alpha decay is this + + align:start position:0% +let's say this top alpha decay is this + + + align:start position:0% +let's say this top alpha decay is this +energy here four point six seven six MeV + + align:start position:0% +energy here four point six seven six MeV + + + align:start position:0% +energy here four point six seven six MeV +minus 0.63 four so use a different Q and + + align:start position:0% +minus 0.63 four so use a different Q and + + + align:start position:0% +minus 0.63 four so use a different Q and +you'll get different TAS and T DS yep so + + align:start position:0% +you'll get different TAS and T DS yep so + + + align:start position:0% +you'll get different TAS and T DS yep so +don't worry you'll get chances to try + + align:start position:0% +don't worry you'll get chances to try + + + align:start position:0% +don't worry you'll get chances to try +out these calculations on the homework + + align:start position:0% +out these calculations on the homework + + + align:start position:0% +out these calculations on the homework +well I'll actually ask you to verify + + align:start position:0% +well I'll actually ask you to verify + + + align:start position:0% +well I'll actually ask you to verify +some of these you know calculate some of + + align:start position:0% +some of these you know calculate some of + + + align:start position:0% +some of these you know calculate some of +these from this equation make sure you + + align:start position:0% +these from this equation make sure you + + + align:start position:0% +these from this equation make sure you +get the same values as the table any + + align:start position:0% +get the same values as the table any + + + align:start position:0% +get the same values as the table any +other questions on alpha decay before + + align:start position:0% +other questions on alpha decay before + + + align:start position:0% +other questions on alpha decay before +moving on to beta we're just going an + + align:start position:0% +moving on to beta we're just going an + + + align:start position:0% +moving on to beta we're just going an +order of the Greek alphabet so beta + + align:start position:0% +order of the Greek alphabet so beta + + + align:start position:0% +order of the Greek alphabet so beta +decay is a kind of funny one you don't + + align:start position:0% +decay is a kind of funny one you don't + + + align:start position:0% +decay is a kind of funny one you don't +tend to get a beta particle out at the + + align:start position:0% +tend to get a beta particle out at the + + + align:start position:0% +tend to get a beta particle out at the +energy of this Q value you actually end + + align:start position:0% +energy of this Q value you actually end + + + align:start position:0% +energy of this Q value you actually end +up getting a spectrum and this measured + + align:start position:0% +up getting a spectrum and this measured + + + align:start position:0% +up getting a spectrum and this measured +spectrum of different beta kinetic + + align:start position:0% +spectrum of different beta kinetic + + + align:start position:0% +spectrum of different beta kinetic +energies is what led to the thoughts + + align:start position:0% +energies is what led to the thoughts + + + align:start position:0% +energies is what led to the thoughts +that there must be something else + + align:start position:0% +that there must be something else + + + align:start position:0% +that there must be something else +carrying away some of that extra mass of + + align:start position:0% +carrying away some of that extra mass of + + + align:start position:0% +carrying away some of that extra mass of +some of that extra energy I say that + + align:start position:0% +some of that extra energy I say that + + + align:start position:0% +some of that extra energy I say that +like it's the same thing because yeah it + + align:start position:0% +like it's the same thing because yeah it + + + align:start position:0% +like it's the same thing because yeah it +totally is and this is what led to the + + align:start position:0% +totally is and this is what led to the + + + align:start position:0% +totally is and this is what led to the +thinking that there's got to be some + + align:start position:0% +thinking that there's got to be some + + + align:start position:0% +thinking that there's got to be some +other very difficult to detect particle + + align:start position:0% +other very difficult to detect particle + + + align:start position:0% +other very difficult to detect particle +so the theorists here we're saying if we + + align:start position:0% +so the theorists here we're saying if we + + + align:start position:0% +so the theorists here we're saying if we +take we know the initial and final + + align:start position:0% +take we know the initial and final + + + align:start position:0% +take we know the initial and final +energies from beta decay and we know + + align:start position:0% +energies from beta decay and we know + + + align:start position:0% +energies from beta decay and we know +that we get a spectrum of different beta + + align:start position:0% +that we get a spectrum of different beta + + + align:start position:0% +that we get a spectrum of different beta +energies and the probability of finding + + align:start position:0% +energies and the probability of finding + + + align:start position:0% +energies and the probability of finding +a beta particle at energy Q drops to + + align:start position:0% +a beta particle at energy Q drops to + + + align:start position:0% +a beta particle at energy Q drops to +like zero you'll almost never see it + + align:start position:0% +like zero you'll almost never see it + + + align:start position:0% +like zero you'll almost never see it +there's + + align:start position:0% +there's + + + align:start position:0% +there's +ought to be something else carrying away + + align:start position:0% +ought to be something else carrying away + + + align:start position:0% +ought to be something else carrying away +the energy so this idea of the neutrino + + align:start position:0% +the energy so this idea of the neutrino + + + align:start position:0% +the energy so this idea of the neutrino +or in this case the anti neutrino was + + align:start position:0% +or in this case the anti neutrino was + + + align:start position:0% +or in this case the anti neutrino was +proposed a long time before it was + + align:start position:0% +proposed a long time before it was + + + align:start position:0% +proposed a long time before it was +confirmed and finally we know why and + + align:start position:0% +confirmed and finally we know why and + + + align:start position:0% +confirmed and finally we know why and +one of the questions I want you to think + + align:start position:0% +one of the questions I want you to think + + + align:start position:0% +one of the questions I want you to think +about because it might be on an exam in + + align:start position:0% +about because it might be on an exam in + + + align:start position:0% +about because it might be on an exam in +exactly two weeks is if this is the + + align:start position:0% +exactly two weeks is if this is the + + + align:start position:0% +exactly two weeks is if this is the +relative number of electrons from beta + + align:start position:0% +relative number of electrons from beta + + + align:start position:0% +relative number of electrons from beta +decay as a function of energy what does + + align:start position:0% +decay as a function of energy what does + + + align:start position:0% +decay as a function of energy what does +the number of anti neutrinos versus + + align:start position:0% +the number of anti neutrinos versus + + + align:start position:0% +the number of anti neutrinos versus +energy look like in order to maintain + + align:start position:0% +energy look like in order to maintain + + + align:start position:0% +energy look like in order to maintain +conservation of energy so it's something + + align:start position:0% +conservation of energy so it's something + + + align:start position:0% +conservation of energy so it's something +I want you guys to think about but I'm + + align:start position:0% +I want you guys to think about but I'm + + + align:start position:0% +I want you guys to think about but I'm +not going to tell you what it is until + + align:start position:0% +not going to tell you what it is until + + + align:start position:0% +not going to tell you what it is until +the solutions for an exam in the + + align:start position:0% +the solutions for an exam in the + + + align:start position:0% +the solutions for an exam in the +meantime what another thing to note is + + align:start position:0% +meantime what another thing to note is + + + align:start position:0% +meantime what another thing to note is +that these beta decays can also be + + align:start position:0% +that these beta decays can also be + + + align:start position:0% +that these beta decays can also be +followed by any number of gamma + + align:start position:0% +followed by any number of gamma + + + align:start position:0% +followed by any number of gamma +transitions I've given you a simple one + + align:start position:0% +transitions I've given you a simple one + + + align:start position:0% +transitions I've given you a simple one +if you want to look up simple ones to + + align:start position:0% +if you want to look up simple ones to + + + align:start position:0% +if you want to look up simple ones to +test your knowledge go with the light + + align:start position:0% +test your knowledge go with the light + + + align:start position:0% +test your knowledge go with the light +elements they don't have that many + + align:start position:0% +elements they don't have that many + + + align:start position:0% +elements they don't have that many +nucleons and they won't have that many + + align:start position:0% +nucleons and they won't have that many + + + align:start position:0% +nucleons and they won't have that many +transitions for example if we pick a + + align:start position:0% +transitions for example if we pick a + + + align:start position:0% +transitions for example if we pick a +beta decay nucleus something simple + + align:start position:0% +beta decay nucleus something simple + + + align:start position:0% +beta decay nucleus something simple +let's go with lithium which typically + + align:start position:0% +let's go with lithium which typically + + + align:start position:0% +let's go with lithium which typically +has the stable isotopes are lithium six + + align:start position:0% +has the stable isotopes are lithium six + + + align:start position:0% +has the stable isotopes are lithium six +or lithium seven so do you think that + + align:start position:0% +or lithium seven so do you think that + + + align:start position:0% +or lithium seven so do you think that +higher or lower mass number lithium will + + align:start position:0% +higher or lower mass number lithium will + + + align:start position:0% +higher or lower mass number lithium will +tend to go by beta decay based on this + + align:start position:0% +tend to go by beta decay based on this + + + align:start position:0% +tend to go by beta decay based on this +generalized decay diagram it's what + + align:start position:0% + + + + align:start position:0% + +lower lower proton number well we got to + + align:start position:0% +lower lower proton number well we got to + + + align:start position:0% +lower lower proton number well we got to +stick with no number of protons because + + align:start position:0% +stick with no number of protons because + + + align:start position:0% +stick with no number of protons because +we need to remain lithium so in other + + align:start position:0% +we need to remain lithium so in other + + + align:start position:0% +we need to remain lithium so in other +words do you expect lithium four and + + align:start position:0% +words do you expect lithium four and + + + align:start position:0% +words do you expect lithium four and +lithium five or lithium eight lithium + + align:start position:0% +lithium five or lithium eight lithium + + + align:start position:0% +lithium five or lithium eight lithium +nine to go by beta decay + + align:start position:0% + + + + align:start position:0% + +the higher ones okay if you guys + + align:start position:0% +the higher ones okay if you guys + + + align:start position:0% +the higher ones okay if you guys +remember the math parabolas from a + + align:start position:0% +remember the math parabolas from a + + + align:start position:0% +remember the math parabolas from a +couple weeks ago we delineated where + + align:start position:0% +couple weeks ago we delineated where + + + align:start position:0% +couple weeks ago we delineated where +you'd expect beta decay in order to + + align:start position:0% +you'd expect beta decay in order to + + + align:start position:0% +you'd expect beta decay in order to +reduce the proton number and positron + + align:start position:0% +reduce the proton number and positron + + + align:start position:0% +reduce the proton number and positron +decay in order I'm sorry beta decay in + + align:start position:0% +decay in order I'm sorry beta decay in + + + align:start position:0% +decay in order I'm sorry beta decay in +order to increase the proton number so + + align:start position:0% +order to increase the proton number so + + + align:start position:0% +order to increase the proton number so +if you've got too many neutrons and not + + align:start position:0% +if you've got too many neutrons and not + + + align:start position:0% +if you've got too many neutrons and not +enough protons chances are beta decay + + align:start position:0% +enough protons chances are beta decay + + + align:start position:0% +enough protons chances are beta decay +will help equalize you out so that's a + + align:start position:0% +will help equalize you out so that's a + + + align:start position:0% +will help equalize you out so that's a +guess I haven't even tried this at home + + align:start position:0% +guess I haven't even tried this at home + + + align:start position:0% +guess I haven't even tried this at home +let's see let's see what happens with + + align:start position:0% +let's see let's see what happens with + + + align:start position:0% +let's see let's see what happens with +lithium eight oh look at that + + align:start position:0% +lithium eight oh look at that + + + align:start position:0% +lithium eight oh look at that +beta decay can also decay by beta plus + + align:start position:0% +beta decay can also decay by beta plus + + + align:start position:0% +beta decay can also decay by beta plus +two alpha which is another word for the + + align:start position:0% +two alpha which is another word for the + + + align:start position:0% +two alpha which is another word for the +nucleus just blows apart it's + + align:start position:0% +nucleus just blows apart it's + + + align:start position:0% +nucleus just blows apart it's +interesting too if you read Chadwicks + + align:start position:0% +interesting too if you read Chadwicks + + + align:start position:0% +interesting too if you read Chadwicks +paper again the way he described a + + align:start position:0% +paper again the way he described a + + + align:start position:0% +paper again the way he described a +beryllium nucleus is consisting of a + + align:start position:0% +beryllium nucleus is consisting of a + + + align:start position:0% +beryllium nucleus is consisting of a +neutron plus two alpha particles + + align:start position:0% +neutron plus two alpha particles + + + align:start position:0% +neutron plus two alpha particles +interesting huh + + align:start position:0% +interesting huh + + + align:start position:0% +interesting huh +lithium nine could decay by or let's say + + align:start position:0% +lithium nine could decay by or let's say + + + align:start position:0% +lithium nine could decay by or let's say +lithium eight what do we have beta plus + + align:start position:0% +lithium eight what do we have beta plus + + + align:start position:0% +lithium eight what do we have beta plus +2 alpha yeah so Chadwick described any + + align:start position:0% +2 alpha yeah so Chadwick described any + + + align:start position:0% +2 alpha yeah so Chadwick described any +nucleus as consisting of these + + align:start position:0% +nucleus as consisting of these + + + align:start position:0% +nucleus as consisting of these +elementary ish particles that you could + + align:start position:0% +elementary ish particles that you could + + + align:start position:0% +elementary ish particles that you could +measure and in this case you kind of see + + align:start position:0% +measure and in this case you kind of see + + + align:start position:0% +measure and in this case you kind of see +a physical example when this nucleus + + align:start position:0% +a physical example when this nucleus + + + align:start position:0% +a physical example when this nucleus +blows apart it just becomes two alphas + + align:start position:0% +blows apart it just becomes two alphas + + + align:start position:0% +blows apart it just becomes two alphas +and a beta interesting but let's look at + + align:start position:0% +and a beta interesting but let's look at + + + align:start position:0% +and a beta interesting but let's look at +the beta decay two beryllium eight + + align:start position:0% +the beta decay two beryllium eight + + + align:start position:0% +the beta decay two beryllium eight +pretty simple you may ask why can't you + + align:start position:0% +pretty simple you may ask why can't you + + + align:start position:0% +pretty simple you may ask why can't you +have beta decay for directly from the + + align:start position:0% +have beta decay for directly from the + + + align:start position:0% +have beta decay for directly from the +highest energy to the ground state + + align:start position:0% +highest energy to the ground state + + + align:start position:0% +highest energy to the ground state +energy that is a 2202 question that I'll + + align:start position:0% +energy that is a 2202 question that I'll + + + align:start position:0% +energy that is a 2202 question that I'll +mention there are allowed and + + align:start position:0% +mention there are allowed and + + + align:start position:0% +mention there are allowed and +unallowable in and energy states so if + + align:start position:0% +unallowable in and energy states so if + + + align:start position:0% +unallowable in and energy states so if +you're wondering why isn't every line + + align:start position:0% +you're wondering why isn't every line + + + align:start position:0% +you're wondering why isn't every line +drawn in the case of really complex + + align:start position:0% +drawn in the case of really complex + + + align:start position:0% +drawn in the case of really complex +nuclei there aren't enough pixels on the + + align:start position:0% +nuclei there aren't enough pixels on the + + + align:start position:0% +nuclei there aren't enough pixels on the +screen sometimes but for the simple + + align:start position:0% +screen sometimes but for the simple + + + align:start position:0% +screen sometimes but for the simple +nuclei there are actually rules of + + align:start position:0% +nuclei there are actually rules of + + + align:start position:0% +nuclei there are actually rules of +selection to decide when you can make + + align:start position:0% +selection to decide when you can make + + + align:start position:0% +selection to decide when you can make +this transition but a lot of beta decays + + align:start position:0% +this transition but a lot of beta decays + + + align:start position:0% +this transition but a lot of beta decays +will usually be something like a beta + + align:start position:0% +will usually be something like a beta + + + align:start position:0% +will usually be something like a beta +decay followed by a gamma so let's see a + + align:start position:0% +decay followed by a gamma so let's see a + + + align:start position:0% +decay followed by a gamma so let's see a +couple of well-known examples for + + align:start position:0% +couple of well-known examples for + + + align:start position:0% +couple of well-known examples for +example carbon-14 this is the basis + + align:start position:0% +example carbon-14 this is the basis + + + align:start position:0% +example carbon-14 this is the basis +behind carbon dating one of those rare + + align:start position:0% +behind carbon dating one of those rare + + + align:start position:0% +behind carbon dating one of those rare +instances when you have a beta decay + + align:start position:0% +instances when you have a beta decay + + + align:start position:0% +instances when you have a beta decay +directly to the ground state it's about + + align:start position:0% +directly to the ground state it's about + + + align:start position:0% +directly to the ground state it's about +as simple as it gets + + align:start position:0% +as simple as it gets + + + align:start position:0% +as simple as it gets +and because the half-life is 5730 years + + align:start position:0% +and because the half-life is 5730 years + + + align:start position:0% +and because the half-life is 5730 years +it's really useful for dating when did + + align:start position:0% +it's really useful for dating when did + + + align:start position:0% +it's really useful for dating when did +an organism or a piece of material die + + align:start position:0% +an organism or a piece of material die + + + align:start position:0% +an organism or a piece of material die +on the timescale of let's say 10 + + align:start position:0% +on the timescale of let's say 10 + + + align:start position:0% +on the timescale of let's say 10 +to tens of thousands of years once + + align:start position:0% +to tens of thousands of years once + + + align:start position:0% +to tens of thousands of years once +you've gone past a few half-lives and + + align:start position:0% +you've gone past a few half-lives and + + + align:start position:0% +you've gone past a few half-lives and +there's very little carbon-14 left there + + align:start position:0% +there's very little carbon-14 left there + + + align:start position:0% +there's very little carbon-14 left there +aren't a lot of decays left and your + + align:start position:0% +aren't a lot of decays left and your + + + align:start position:0% +aren't a lot of decays left and your +counting statistics get crappy and it + + align:start position:0% +counting statistics get crappy and it + + + align:start position:0% +counting statistics get crappy and it +gets harder and harder to carbon-date + + align:start position:0% +gets harder and harder to carbon-date + + + align:start position:0% +gets harder and harder to carbon-date +things the basis behind this is that all + + align:start position:0% +things the basis behind this is that all + + + align:start position:0% +things the basis behind this is that all +living organisms that are in taking an + + align:start position:0% +living organisms that are in taking an + + + align:start position:0% +living organisms that are in taking an +exhaling carbon by some means remain an + + align:start position:0% +exhaling carbon by some means remain an + + + align:start position:0% +exhaling carbon by some means remain an +isotopic equilibrium with the carbon + + align:start position:0% +isotopic equilibrium with the carbon + + + align:start position:0% +isotopic equilibrium with the carbon +surrounding them and while most carbon + + align:start position:0% +surrounding them and while most carbon + + + align:start position:0% +surrounding them and while most carbon +is co2 and sand food and whatever is + + align:start position:0% +is co2 and sand food and whatever is + + + align:start position:0% +is co2 and sand food and whatever is +carbon-12 you're going to have a little + + align:start position:0% +carbon-12 you're going to have a little + + + align:start position:0% +carbon-12 you're going to have a little +bit of carbon-14 production from the + + align:start position:0% +bit of carbon-14 production from the + + + align:start position:0% +bit of carbon-14 production from the +upper atmosphere this is usually a + + align:start position:0% +upper atmosphere this is usually a + + + align:start position:0% +upper atmosphere this is usually a +cosmic ray phenomenon which we'll get + + align:start position:0% +cosmic ray phenomenon which we'll get + + + align:start position:0% +cosmic ray phenomenon which we'll get +into when we get into cosmic rays the + + align:start position:0% +into when we get into cosmic rays the + + + align:start position:0% +into when we get into cosmic rays the +moment you die you stop in taking carbon + + align:start position:0% +moment you die you stop in taking carbon + + + align:start position:0% +moment you die you stop in taking carbon +and the little bit of carbon-14 in the + + align:start position:0% +and the little bit of carbon-14 in the + + + align:start position:0% +and the little bit of carbon-14 in the +cloth and the food and your body + + align:start position:0% +cloth and the food and your body + + + align:start position:0% +cloth and the food and your body +whatever starts to decay naturally with + + align:start position:0% +whatever starts to decay naturally with + + + align:start position:0% +whatever starts to decay naturally with +a very regular decay curve and so this + + align:start position:0% +a very regular decay curve and so this + + + align:start position:0% +a very regular decay curve and so this +is the whole basis behind carbon dating + + align:start position:0% +is the whole basis behind carbon dating + + + align:start position:0% +is the whole basis behind carbon dating +and in the next pset you'll actually see + + align:start position:0% +and in the next pset you'll actually see + + + align:start position:0% +and in the next pset you'll actually see +how this was used to debunk the Shroud + + align:start position:0% +how this was used to debunk the Shroud + + + align:start position:0% +how this was used to debunk the Shroud +of Turin or the supposed burial cloth of + + align:start position:0% +of Turin or the supposed burial cloth of + + + align:start position:0% +of Turin or the supposed burial cloth of +Jesus of Nazareth because the carbon + + align:start position:0% +Jesus of Nazareth because the carbon + + + align:start position:0% +Jesus of Nazareth because the carbon +dating data just didn't check out as + + align:start position:0% +dating data just didn't check out as + + + align:start position:0% +dating data just didn't check out as +much as people really wanted to feel + + align:start position:0% +much as people really wanted to feel + + + align:start position:0% +much as people really wanted to feel +like we found it no science that's the + + align:start position:0% +like we found it no science that's the + + + align:start position:0% +like we found it no science that's the +answer no another well-known one we've + + align:start position:0% +answer no another well-known one we've + + + align:start position:0% +answer no another well-known one we've +talked about before is molybdenum-99 + + align:start position:0% +talked about before is molybdenum-99 + + + align:start position:0% +talked about before is molybdenum-99 +decaying to technetium-99 metastable + + align:start position:0% +decaying to technetium-99 metastable + + + align:start position:0% +decaying to technetium-99 metastable +notice how here any number of beta + + align:start position:0% +notice how here any number of beta + + + align:start position:0% +notice how here any number of beta +decays and any cascade of very fast + + align:start position:0% +decays and any cascade of very fast + + + align:start position:0% +decays and any cascade of very fast +gamma transitions they almost all end + + align:start position:0% +gamma transitions they almost all end + + + align:start position:0% +gamma transitions they almost all end +right here at this state of about C + + align:start position:0% +right here at this state of about C + + + align:start position:0% +right here at this state of about C +there's two numbers written over each + + align:start position:0% +there's two numbers written over each + + + align:start position:0% +there's two numbers written over each +other but it's about a hundred and forty + + align:start position:0% +other but it's about a hundred and forty + + + align:start position:0% +other but it's about a hundred and forty +ke V or 0.14 MeV this transition from + + align:start position:0% +ke V or 0.14 MeV this transition from + + + align:start position:0% +ke V or 0.14 MeV this transition from +this state to the ground state is a slow + + align:start position:0% +this state to the ground state is a slow + + + align:start position:0% +this state to the ground state is a slow +transition so you can actually build up + + align:start position:0% +transition so you can actually build up + + + align:start position:0% +transition so you can actually build up +technetium-99 in what's called series + + align:start position:0% +technetium-99 in what's called series + + + align:start position:0% +technetium-99 in what's called series +decay which were going to cover on + + align:start position:0% +decay which were going to cover on + + + align:start position:0% +decay which were going to cover on +Friday and then you can use these 140 ke + + align:start position:0% +Friday and then you can use these 140 ke + + + align:start position:0% +Friday and then you can use these 140 ke +V gamma rays to do medical imaging so + + align:start position:0% +V gamma rays to do medical imaging so + + + align:start position:0% +V gamma rays to do medical imaging so +when you get a medical imaging procedure + + align:start position:0% +when you get a medical imaging procedure + + + align:start position:0% +when you get a medical imaging procedure +done chances are this is how it's done + + align:start position:0% +done chances are this is how it's done + + + align:start position:0% +done chances are this is how it's done +you get Molly 99 out of a reactor or an + + align:start position:0% +you get Molly 99 out of a reactor or an + + + align:start position:0% +you get Molly 99 out of a reactor or an +accelerator Technic a toda that + + align:start position:0% +accelerator Technic a toda that + + + align:start position:0% +accelerator Technic a toda that +chemically isolate the technetium-99 + + align:start position:0% +chemically isolate the technetium-99 + + + align:start position:0% +chemically isolate the technetium-99 +metastable which lasts on the order of + + align:start position:0% +metastable which lasts on the order of + + + align:start position:0% +metastable which lasts on the order of +six days or so very quickly get it to + + align:start position:0% +six days or so very quickly get it to + + + align:start position:0% +six days or so very quickly get it to +someone inject it an image where do the + + align:start position:0% +someone inject it an image where do the + + + align:start position:0% +someone inject it an image where do the +gamma rays go + + align:start position:0% +gamma rays go + + + align:start position:0% +gamma rays go +or what are the gamma rays come from one + + align:start position:0% +or what are the gamma rays come from one + + + align:start position:0% +or what are the gamma rays come from one +last notable one is responsible for a + + align:start position:0% +last notable one is responsible for a + + + align:start position:0% +last notable one is responsible for a +lot of well problems when folks go urban + + align:start position:0% +lot of well problems when folks go urban + + + align:start position:0% +lot of well problems when folks go urban +exploring an old dentists offices + + align:start position:0% +exploring an old dentists offices + + + align:start position:0% +exploring an old dentists offices +nowadays they have electrostatic x-ray + + align:start position:0% +nowadays they have electrostatic x-ray + + + align:start position:0% +nowadays they have electrostatic x-ray +machines at dentists offices but back in + + align:start position:0% +machines at dentists offices but back in + + + align:start position:0% +machines at dentists offices but back in +the day you could get a little button of + + align:start position:0% +the day you could get a little button of + + + align:start position:0% +the day you could get a little button of +cobalt-60 which would emit two very + + align:start position:0% +cobalt-60 which would emit two very + + + align:start position:0% +cobalt-60 which would emit two very +characteristic gamma rays in addition to + + align:start position:0% +characteristic gamma rays in addition to + + + align:start position:0% +characteristic gamma rays in addition to +its beta decays so normally what happens + + align:start position:0% +its beta decays so normally what happens + + + align:start position:0% +its beta decays so normally what happens +is cobalt-60 decays quickly to an + + align:start position:0% +is cobalt-60 decays quickly to an + + + align:start position:0% +is cobalt-60 decays quickly to an +excited state and gives off two gamma + + align:start position:0% +excited state and gives off two gamma + + + align:start position:0% +excited state and gives off two gamma +rays an accession succession which would + + align:start position:0% +rays an accession succession which would + + + align:start position:0% +rays an accession succession which would +be used for imaging problem is that's a + + align:start position:0% +be used for imaging problem is that's a + + + align:start position:0% +be used for imaging problem is that's a +radioactive cobalt source and if you + + align:start position:0% +radioactive cobalt source and if you + + + align:start position:0% +radioactive cobalt source and if you +don't know what it is and you're like oh + + align:start position:0% +don't know what it is and you're like oh + + + align:start position:0% +don't know what it is and you're like oh +cool what's this blue thing I think I'll + + align:start position:0% +cool what's this blue thing I think I'll + + + align:start position:0% +cool what's this blue thing I think I'll +put it in my pocket and keep it that has + + align:start position:0% +put it in my pocket and keep it that has + + + align:start position:0% +put it in my pocket and keep it that has +been responsible for some injuries from + + align:start position:0% +been responsible for some injuries from + + + align:start position:0% +been responsible for some injuries from +some folks that didn't know any better + + align:start position:0% +some folks that didn't know any better + + + align:start position:0% +some folks that didn't know any better +then how do you detect the neutrinos we + + align:start position:0% +then how do you detect the neutrinos we + + + align:start position:0% +then how do you detect the neutrinos we +talked about the theoretical reason why + + align:start position:0% +talked about the theoretical reason why + + + align:start position:0% +talked about the theoretical reason why +they exist let's actually see how + + align:start position:0% +they exist let's actually see how + + + align:start position:0% +they exist let's actually see how +they're measured there's a hollowed-out + + align:start position:0% +they're measured there's a hollowed-out + + + align:start position:0% +they're measured there's a hollowed-out +salt mine of some sort called kamiokande + + align:start position:0% +salt mine of some sort called kamiokande + + + align:start position:0% +salt mine of some sort called kamiokande +in Japan it's a humongous Hall in the + + align:start position:0% +in Japan it's a humongous Hall in the + + + align:start position:0% +in Japan it's a humongous Hall in the +ground filled with water for a reason + + align:start position:0% +ground filled with water for a reason + + + align:start position:0% +ground filled with water for a reason +and lined with tens of thousands of + + align:start position:0% +and lined with tens of thousands of + + + align:start position:0% +and lined with tens of thousands of +highly sensitive photo tubes that can + + align:start position:0% +highly sensitive photo tubes that can + + + align:start position:0% +highly sensitive photo tubes that can +pick up tiny tiny amounts of light the + + align:start position:0% +pick up tiny tiny amounts of light the + + + align:start position:0% +pick up tiny tiny amounts of light the +reason for this is because neutrinos as + + align:start position:0% +reason for this is because neutrinos as + + + align:start position:0% +reason for this is because neutrinos as +you saw in problem set 1 are always + + align:start position:0% +you saw in problem set 1 are always + + + align:start position:0% +you saw in problem set 1 are always +traveling near the speed of light in a + + align:start position:0% +traveling near the speed of light in a + + + align:start position:0% +traveling near the speed of light in a +vacuum so if the speed of light in a + + align:start position:0% +vacuum so if the speed of light in a + + + align:start position:0% +vacuum so if the speed of light in a +vacuum let's call that one and the + + align:start position:0% +vacuum let's call that one and the + + + align:start position:0% +vacuum let's call that one and the +velocity of the neutrino wasn't it + + align:start position:0% +velocity of the neutrino wasn't it + + + align:start position:0% +velocity of the neutrino wasn't it +something like 0.999 C or something like + + align:start position:0% +something like 0.999 C or something like + + + align:start position:0% +something like 0.999 C or something like +that it was pretty high the speed of + + align:start position:0% +that it was pretty high the speed of + + + align:start position:0% +that it was pretty high the speed of +light and water is significantly less + + align:start position:0% +light and water is significantly less + + + align:start position:0% +light and water is significantly less +than the speed of light in a vacuum when + + align:start position:0% +than the speed of light in a vacuum when + + + align:start position:0% +than the speed of light in a vacuum when +you have a material or a particle that + + align:start position:0% +you have a material or a particle that + + + align:start position:0% +you have a material or a particle that +goes faster than the speed of light in + + align:start position:0% +goes faster than the speed of light in + + + align:start position:0% +goes faster than the speed of light in +the medium that it's traveling in then + + align:start position:0% +the medium that it's traveling in then + + + align:start position:0% +the medium that it's traveling in then +you can produce what's called Cherenkov + + align:start position:0% +you can produce what's called Cherenkov + + + align:start position:0% +you can produce what's called Cherenkov +radiation which I think I've mentioned + + align:start position:0% +radiation which I think I've mentioned + + + align:start position:0% +radiation which I think I've mentioned +once before it's kind of like a sonic + + align:start position:0% +once before it's kind of like a sonic + + + align:start position:0% +once before it's kind of like a sonic +boom in that you get a conical shock + + align:start position:0% +boom in that you get a conical shock + + + align:start position:0% +boom in that you get a conical shock +wave of energy radiated from that + + align:start position:0% +wave of energy radiated from that + + + align:start position:0% +wave of energy radiated from that +particle that tells you which direction + + align:start position:0% +particle that tells you which direction + + + align:start position:0% +particle that tells you which direction +it's coming from but instead of a sound + + align:start position:0% +it's coming from but instead of a sound + + + align:start position:0% +it's coming from but instead of a sound +wave you get light and this whole + + align:start position:0% +wave you get light and this whole + + + align:start position:0% +wave you get light and this whole +detector is designed to look at the + + align:start position:0% +detector is designed to look at the + + + align:start position:0% +detector is designed to look at the +ellipses of Cherenkov radiation released + + align:start position:0% +ellipses of Cherenkov radiation released + + + align:start position:0% +ellipses of Cherenkov radiation released +by neutrinos and antineutrinos so what + + align:start position:0% +by neutrinos and antineutrinos so what + + + align:start position:0% +by neutrinos and antineutrinos so what +happens is if a neutrino happens to + + align:start position:0% +happens is if a neutrino happens to + + + align:start position:0% +happens is if a neutrino happens to +interact with the water here it produces + + align:start position:0% +interact with the water here it produces + + + align:start position:0% +interact with the water here it produces +Cherenkov radiation lighting up a ring + + align:start position:0% +Cherenkov radiation lighting up a ring + + + align:start position:0% +Cherenkov radiation lighting up a ring +of these detectors so you can tell it's + + align:start position:0% +of these detectors so you can tell it's + + + align:start position:0% +of these detectors so you can tell it's +energy and you can tell where it came + + align:start position:0% +energy and you can tell where it came + + + align:start position:0% +energy and you can tell where it came +from so if you let's say cone correlate + + align:start position:0% +from so if you let's say cone correlate + + + align:start position:0% +from so if you let's say cone correlate +a supernova or some sort of crazy + + align:start position:0% +a supernova or some sort of crazy + + + align:start position:0% +a supernova or some sort of crazy +galactic whatever with a slight burst of + + align:start position:0% +galactic whatever with a slight burst of + + + align:start position:0% +galactic whatever with a slight burst of +neutrinos then you've got a pretty + + align:start position:0% +neutrinos then you've got a pretty + + + align:start position:0% +neutrinos then you've got a pretty +significant astronomical event it also + + align:start position:0% +significant astronomical event it also + + + align:start position:0% +significant astronomical event it also +led to my favorite BBC headline ever + + align:start position:0% +led to my favorite BBC headline ever + + + align:start position:0% +led to my favorite BBC headline ever +particle physics telescope explodes + + align:start position:0% +particle physics telescope explodes + + + align:start position:0% +particle physics telescope explodes +you'd see this on like fox news or + + align:start position:0% +you'd see this on like fox news or + + + align:start position:0% +you'd see this on like fox news or +something no this was the BBC what + + align:start position:0% +something no this was the BBC what + + + align:start position:0% +something no this was the BBC what +happened here is one of these 30,000 or + + align:start position:0% +happened here is one of these 30,000 or + + + align:start position:0% +happened here is one of these 30,000 or +so tubes was slightly defective couldn't + + align:start position:0% +so tubes was slightly defective couldn't + + + align:start position:0% +so tubes was slightly defective couldn't +hold the pressure and it burst and the + + align:start position:0% +hold the pressure and it burst and the + + + align:start position:0% +hold the pressure and it burst and the +resulting sound shockwave from one photo + + align:start position:0% +resulting sound shockwave from one photo + + + align:start position:0% +resulting sound shockwave from one photo +- bursting blew up about 11,000 of them + + align:start position:0% +- bursting blew up about 11,000 of them + + + align:start position:0% +- bursting blew up about 11,000 of them +so yeah the particle physics telescope + + align:start position:0% +so yeah the particle physics telescope + + + align:start position:0% +so yeah the particle physics telescope +kind of did explode they did rebuild it + + align:start position:0% +kind of did explode they did rebuild it + + + align:start position:0% +kind of did explode they did rebuild it +and it's still going it was an expensive + + align:start position:0% +and it's still going it was an expensive + + + align:start position:0% +and it's still going it was an expensive +repair cuz all eleven thousand three + + align:start position:0% +repair cuz all eleven thousand three + + + align:start position:0% +repair cuz all eleven thousand three +hundred something tubes had to be + + align:start position:0% +hundred something tubes had to be + + + align:start position:0% +hundred something tubes had to be +rebuilt and if you noticed there was a + + align:start position:0% +rebuilt and if you noticed there was a + + + align:start position:0% +rebuilt and if you noticed there was a +guy on a boat there how do you install + + align:start position:0% +guy on a boat there how do you install + + + align:start position:0% +guy on a boat there how do you install +them well you float on a boat quietly + + align:start position:0% +them well you float on a boat quietly + + + align:start position:0% +them well you float on a boat quietly +and put the photo tubes in and raise the + + align:start position:0% +and put the photo tubes in and raise the + + + align:start position:0% +and put the photo tubes in and raise the +water level and float to another part of + + align:start position:0% +water level and float to another part of + + + align:start position:0% +water level and float to another part of +the Tector quietly and continue + + align:start position:0% +the Tector quietly and continue + + + align:start position:0% +the Tector quietly and continue +installing the photo tubes until you're + + align:start position:0% +installing the photo tubes until you're + + + align:start position:0% +installing the photo tubes until you're +done yeah you don't ya don't sneeze so + + align:start position:0% +done yeah you don't ya don't sneeze so + + + align:start position:0% +done yeah you don't ya don't sneeze so +ya favorite BBC headline ever thanks + + align:start position:0% +ya favorite BBC headline ever thanks + + + align:start position:0% +ya favorite BBC headline ever thanks +again science for a positron decay okay + + align:start position:0% +again science for a positron decay okay + + + align:start position:0% +again science for a positron decay okay +we've got about 10 minutes left for + + align:start position:0% +we've got about 10 minutes left for + + + align:start position:0% +we've got about 10 minutes left for +positron decay this is the energy that + + align:start position:0% +positron decay this is the energy that + + + align:start position:0% +positron decay this is the energy that +you need in order to make a positron it + + align:start position:0% +you need in order to make a positron it + + + align:start position:0% +you need in order to make a positron it +is approximately exactly double the MER + + align:start position:0% +is approximately exactly double the MER + + + align:start position:0% +is approximately exactly double the MER +rest mass of an electron and the + + align:start position:0% +rest mass of an electron and the + + + align:start position:0% +rest mass of an electron and the +question usually comes up well a + + align:start position:0% +question usually comes up well a + + + align:start position:0% +question usually comes up well a +positron has a rest mass energy of 0.5 1 + + align:start position:0% +positron has a rest mass energy of 0.5 1 + + + align:start position:0% +positron has a rest mass energy of 0.5 1 +1 MeV why do you need double that to + + align:start position:0% +1 MeV why do you need double that to + + + align:start position:0% +1 MeV why do you need double that to +make the positron because in order to + + align:start position:0% +make the positron because in order to + + + align:start position:0% +make the positron because in order to +conserve the charge of the system you + + align:start position:0% +conserve the charge of the system you + + + align:start position:0% +conserve the charge of the system you +have to shed an orbital electron so the + + align:start position:0% +have to shed an orbital electron so the + + + align:start position:0% +have to shed an orbital electron so the +system has got to be able to lose two + + align:start position:0% +system has got to be able to lose two + + + align:start position:0% +system has got to be able to lose two +electrons in the process of one + + align:start position:0% +electrons in the process of one + + + align:start position:0% +electrons in the process of one +positively charged and one negatively + + align:start position:0% +positively charged and one negatively + + + align:start position:0% +positively charged and one negatively +charged and so that's why the + + align:start position:0% +charged and so that's why the + + + align:start position:0% +charged and so that's why the +q for positron decay is just gonna be + + align:start position:0% +q for positron decay is just gonna be + + + align:start position:0% +q for positron decay is just gonna be +remember the symbols the excess mass + + align:start position:0% +remember the symbols the excess mass + + + align:start position:0% +remember the symbols the excess mass +here excess mass of the parent - SS mass + + align:start position:0% +here excess mass of the parent - SS mass + + + align:start position:0% +here excess mass of the parent - SS mass +of the daughter - two times the rest + + align:start position:0% +of the daughter - two times the rest + + + align:start position:0% +of the daughter - two times the rest +mass of the electrons squared to refresh + + align:start position:0% +mass of the electrons squared to refresh + + + align:start position:0% +mass of the electrons squared to refresh +your memories a bit find some empty + + align:start position:0% +your memories a bit find some empty + + + align:start position:0% +your memories a bit find some empty +space the excess mass is nothing more + + align:start position:0% +space the excess mass is nothing more + + + align:start position:0% +space the excess mass is nothing more +than the mass - the horrible + + align:start position:0% +than the mass - the horrible + + + align:start position:0% +than the mass - the horrible +approximation of the mass so the excess + + align:start position:0% +approximation of the mass so the excess + + + align:start position:0% +approximation of the mass so the excess +mass and the real mass are directly + + align:start position:0% +mass and the real mass are directly + + + align:start position:0% +mass and the real mass are directly +related and these are things that you + + align:start position:0% +related and these are things that you + + + align:start position:0% +related and these are things that you +can look up just to remind you guys that + + align:start position:0% +can look up just to remind you guys that + + + align:start position:0% +can look up just to remind you guys that +excess mass and mass and binding energy + + align:start position:0% +excess mass and mass and binding energy + + + align:start position:0% +excess mass and mass and binding energy +and kinetic energy are all related again + + align:start position:0% +and kinetic energy are all related again + + + align:start position:0% +and kinetic energy are all related again +by the Q equation it's probably the last + + align:start position:0% +by the Q equation it's probably the last + + + align:start position:0% +by the Q equation it's probably the last +time I'll say it cuz I think that's + + align:start position:0% +time I'll say it cuz I think that's + + + align:start position:0% +time I'll say it cuz I think that's +about a hundred by my count positrons + + align:start position:0% +about a hundred by my count positrons + + + align:start position:0% +about a hundred by my count positrons +can be used for some pretty awesome + + align:start position:0% +can be used for some pretty awesome + + + align:start position:0% +can be used for some pretty awesome +things and I will in the last five + + align:start position:0% +things and I will in the last five + + + align:start position:0% +things and I will in the last five +minutes of show I want to show you some + + align:start position:0% +minutes of show I want to show you some + + + align:start position:0% +minutes of show I want to show you some +work done by Professor Brian Werth at + + align:start position:0% +work done by Professor Brian Werth at + + + align:start position:0% +work done by Professor Brian Werth at +the University of Tennessee Knoxville on + + align:start position:0% +the University of Tennessee Knoxville on + + + align:start position:0% +the University of Tennessee Knoxville on +positron annihilation spectroscopy using + + align:start position:0% +positron annihilation spectroscopy using + + + align:start position:0% +positron annihilation spectroscopy using +antimatter to probe matter and find out + + align:start position:0% +antimatter to probe matter and find out + + + align:start position:0% +antimatter to probe matter and find out +what sort of defects exist and as a + + align:start position:0% +what sort of defects exist and as a + + + align:start position:0% +what sort of defects exist and as a +nuclear material scientist I'd be well + + align:start position:0% +nuclear material scientist I'd be well + + + align:start position:0% +nuclear material scientist I'd be well +terrible if I didn't inject a little bit + + align:start position:0% +terrible if I didn't inject a little bit + + + align:start position:0% +terrible if I didn't inject a little bit +of materials and how we use nuclear + + align:start position:0% +of materials and how we use nuclear + + + align:start position:0% +of materials and how we use nuclear +stuff in 2201 in order to probe that + + align:start position:0% +stuff in 2201 in order to probe that + + + align:start position:0% +stuff in 2201 in order to probe that +thing so the way that positron + + align:start position:0% +thing so the way that positron + + + align:start position:0% +thing so the way that positron +annihilation spectroscopy works is that + + align:start position:0% +annihilation spectroscopy works is that + + + align:start position:0% +annihilation spectroscopy works is that +well matters mostly empty space and in a + + align:start position:0% +well matters mostly empty space and in a + + + align:start position:0% +well matters mostly empty space and in a +in a regular crystal lattice where the + + align:start position:0% +in a regular crystal lattice where the + + + align:start position:0% +in a regular crystal lattice where the +atoms are arranged in a very regular + + align:start position:0% +atoms are arranged in a very regular + + + align:start position:0% +atoms are arranged in a very regular +array let's say these atoms have their + + align:start position:0% +array let's say these atoms have their + + + align:start position:0% +array let's say these atoms have their +orbital electrons the empty space + + align:start position:0% +orbital electrons the empty space + + + align:start position:0% +orbital electrons the empty space +between is also arranged in a very + + align:start position:0% +between is also arranged in a very + + + align:start position:0% +between is also arranged in a very +regular array and positrons annihilated + + align:start position:0% +regular array and positrons annihilated + + + align:start position:0% +regular array and positrons annihilated +electrons to produce well we'll find out + + align:start position:0% +electrons to produce well we'll find out + + + align:start position:0% +electrons to produce well we'll find out +in a second but we're in matter would + + align:start position:0% +in a second but we're in matter would + + + align:start position:0% +in a second but we're in matter would +they want to live or where were they + + align:start position:0% +they want to live or where were they + + + align:start position:0% +they want to live or where were they +last longer not near an atom but near + + align:start position:0% +last longer not near an atom but near + + + align:start position:0% +last longer not near an atom but near +the space in between so you can map out + + align:start position:0% +the space in between so you can map out + + + align:start position:0% +the space in between so you can map out +the empty spaces in matter in a regular + + align:start position:0% +the empty spaces in matter in a regular + + + align:start position:0% +the empty spaces in matter in a regular +crystal and calculate an average + + align:start position:0% +crystal and calculate an average + + + align:start position:0% +crystal and calculate an average +positron lifetime if you were to fire a + + align:start position:0% +positron lifetime if you were to fire a + + + align:start position:0% +positron lifetime if you were to fire a +positron into this matter how long would + + align:start position:0% +positron into this matter how long would + + + align:start position:0% +positron into this matter how long would +it sit and bounce around before + + align:start position:0% +it sit and bounce around before + + + align:start position:0% +it sit and bounce around before +colliding with an electron and releasing + + align:start position:0% +colliding with an electron and releasing + + + align:start position:0% +colliding with an electron and releasing +that extra rest mass energy it turns out + + align:start position:0% +that extra rest mass energy it turns out + + + align:start position:0% +that extra rest mass energy it turns out +if you have crystalline defects but + + align:start position:0% +if you have crystalline defects but + + + align:start position:0% +if you have crystalline defects but +positrons tend to last a little longer + + align:start position:0% +positrons tend to last a little longer + + + align:start position:0% +positrons tend to last a little longer +there's a little more empty space which + + align:start position:0% +there's a little more empty space which + + + align:start position:0% +there's a little more empty space which +is to say there are more places with a + + align:start position:0% +is to say there are more places with a + + + align:start position:0% +is to say there are more places with a +slightly less probability of finding an + + align:start position:0% +slightly less probability of finding an + + + align:start position:0% +slightly less probability of finding an +electron and so they last longer and you + + align:start position:0% +electron and so they last longer and you + + + align:start position:0% +electron and so they last longer and you +can measure the lifetime of positrons as + + align:start position:0% +can measure the lifetime of positrons as + + + align:start position:0% +can measure the lifetime of positrons as +they before they enter the material and + + align:start position:0% +they before they enter the material and + + + align:start position:0% +they before they enter the material and +then how long before they produce their + + align:start position:0% +then how long before they produce their + + + align:start position:0% +then how long before they produce their +characteristic destruction gamma rays so + + align:start position:0% +characteristic destruction gamma rays so + + + align:start position:0% +characteristic destruction gamma rays so +if you think about it you have a + + align:start position:0% +if you think about it you have a + + + align:start position:0% +if you think about it you have a +positron coming in with a rest mass 0.51 + + align:start position:0% +positron coming in with a rest mass 0.51 + + + align:start position:0% +positron coming in with a rest mass 0.51 +one MeV and it collides with an electron + + align:start position:0% +one MeV and it collides with an electron + + + align:start position:0% +one MeV and it collides with an electron +from some orbital nucleus that has the + + align:start position:0% +from some orbital nucleus that has the + + + align:start position:0% +from some orbital nucleus that has the +same rest mass the positron and the + + align:start position:0% +same rest mass the positron and the + + + align:start position:0% +same rest mass the positron and the +electron annihilate sending off gamma + + align:start position:0% +electron annihilate sending off gamma + + + align:start position:0% +electron annihilate sending off gamma +rays in opposite directions where the + + align:start position:0% +rays in opposite directions where the + + + align:start position:0% +rays in opposite directions where the +energy of this gamma is the same thing + + align:start position:0% +energy of this gamma is the same thing + + + align:start position:0% +energy of this gamma is the same thing +point five one one MeV so you can tell + + align:start position:0% +point five one one MeV so you can tell + + + align:start position:0% +point five one one MeV so you can tell +when a positron was destroyed because + + align:start position:0% +when a positron was destroyed because + + + align:start position:0% +when a positron was destroyed because +you instantly get a half MeV gamma ray + + align:start position:0% +you instantly get a half MeV gamma ray + + + align:start position:0% +you instantly get a half MeV gamma ray +or actually you get two half MeV gamma + + align:start position:0% +or actually you get two half MeV gamma + + + align:start position:0% +or actually you get two half MeV gamma +rays then the question is how do you + + align:start position:0% +rays then the question is how do you + + + align:start position:0% +rays then the question is how do you +tell its lifetime let's go back to + + align:start position:0% +tell its lifetime let's go back to + + + align:start position:0% +tell its lifetime let's go back to +something that I didn't quite point out + + align:start position:0% +something that I didn't quite point out + + + align:start position:0% +something that I didn't quite point out +but I want to show you now is this + + align:start position:0% +but I want to show you now is this + + + align:start position:0% +but I want to show you now is this +positron decay is immediately followed + + align:start position:0% +positron decay is immediately followed + + + align:start position:0% +positron decay is immediately followed +by a one point two seven MeV gamma ray + + align:start position:0% +by a one point two seven MeV gamma ray + + + align:start position:0% +by a one point two seven MeV gamma ray +which is in pas or positron annihilation + + align:start position:0% +which is in pas or positron annihilation + + + align:start position:0% +which is in pas or positron annihilation +spectroscopy we call this the birth + + align:start position:0% +spectroscopy we call this the birth + + + align:start position:0% +spectroscopy we call this the birth +gamma ray this gamma ray is emitted the + + align:start position:0% +gamma ray this gamma ray is emitted the + + + align:start position:0% +gamma ray this gamma ray is emitted the +instant this nucleus is born and the + + align:start position:0% +instant this nucleus is born and the + + + align:start position:0% +instant this nucleus is born and the +positron takes a little bit of time to + + align:start position:0% +positron takes a little bit of time to + + + align:start position:0% +positron takes a little bit of time to +get destroyed + + align:start position:0% +get destroyed + + + align:start position:0% +get destroyed +so you actually look at the difference + + align:start position:0% +so you actually look at the difference + + + align:start position:0% +so you actually look at the difference +in time between sensing the 1.27 MeV + + align:start position:0% +in time between sensing the 1.27 MeV + + + align:start position:0% +in time between sensing the 1.27 MeV +gamma ray and the 0.5 one 1 MeV + + align:start position:0% +gamma ray and the 0.5 one 1 MeV + + + align:start position:0% +gamma ray and the 0.5 one 1 MeV +annihilation photons and that is + + align:start position:0% +annihilation photons and that is + + + align:start position:0% +annihilation photons and that is +measured in let's say hundreds of Pico + + align:start position:0% +measured in let's say hundreds of Pico + + + align:start position:0% +measured in let's say hundreds of Pico +seconds with resolution of around 5 Pico + + align:start position:0% +seconds with resolution of around 5 Pico + + + align:start position:0% +seconds with resolution of around 5 Pico +seconds and you can then tell from the + + align:start position:0% +seconds and you can then tell from the + + + align:start position:0% +seconds and you can then tell from the +lifetime at how many survived what sort + + align:start position:0% +lifetime at how many survived what sort + + + align:start position:0% +lifetime at how many survived what sort +of atomic defects might exist in the + + align:start position:0% +of atomic defects might exist in the + + + align:start position:0% +of atomic defects might exist in the +material so if you want to count the + + align:start position:0% +material so if you want to count the + + + align:start position:0% +material so if you want to count the +number of missing atoms or vacancies in + + align:start position:0% +number of missing atoms or vacancies in + + + align:start position:0% +number of missing atoms or vacancies in +a material which is extremely important + + align:start position:0% +a material which is extremely important + + + align:start position:0% +a material which is extremely important +to those of us in radiation damage you + + align:start position:0% +to those of us in radiation damage you + + + align:start position:0% +to those of us in radiation damage you +can do so with positron annihilation + + align:start position:0% +can do so with positron annihilation + + + align:start position:0% +can do so with positron annihilation +spectroscopy so I think I wanted to show + + align:start position:0% +spectroscopy so I think I wanted to show + + + align:start position:0% +spectroscopy so I think I wanted to show +you a little bit about how this works + + align:start position:0% +you a little bit about how this works + + + align:start position:0% +you a little bit about how this works +you start off by making a radioactive + + align:start position:0% +you start off by making a radioactive + + + align:start position:0% +you start off by making a radioactive +salt sandwich you take some sodium + + align:start position:0% +salt sandwich you take some sodium + + + align:start position:0% +salt sandwich you take some sodium +chloride specifically of the isotope + + align:start position:0% +chloride specifically of the isotope + + + align:start position:0% +chloride specifically of the isotope +sodium 22 which is giving off positrons + + align:start position:0% +sodium 22 which is giving off positrons + + + align:start position:0% +sodium 22 which is giving off positrons +all the time and you sandwich that + + align:start position:0% +all the time and you sandwich that + + + align:start position:0% +all the time and you sandwich that +radioactive jelly between the two slices + + align:start position:0% +radioactive jelly between the two slices + + + align:start position:0% +radioactive jelly between the two slices +of bread better known as your sample + + align:start position:0% +of bread better known as your sample + + + align:start position:0% +of bread better known as your sample +that way you catch every positron that + + align:start position:0% +that way you catch every positron that + + + align:start position:0% +that way you catch every positron that +gets out so you don't lose half of them + + align:start position:0% +gets out so you don't lose half of them + + + align:start position:0% +gets out so you don't lose half of them +to one side you've got two detectors on + + align:start position:0% +to one side you've got two detectors on + + + align:start position:0% +to one side you've got two detectors on +either side waiting so that that's + + align:start position:0% +either side waiting so that that's + + + align:start position:0% +either side waiting so that that's +there's some probability that the + + align:start position:0% +there's some probability that the + + + align:start position:0% +there's some probability that the +photons emitted are going to go in the + + align:start position:0% +photons emitted are going to go in the + + + align:start position:0% +photons emitted are going to go in the +direction of the detectors so you miss + + align:start position:0% +direction of the detectors so you miss + + + align:start position:0% +direction of the detectors so you miss +most of the signal but so what + + align:start position:0% +most of the signal but so what + + + align:start position:0% +most of the signal but so what +whenever you actually sense a 1.27 MeV + + align:start position:0% +whenever you actually sense a 1.27 MeV + + + align:start position:0% +whenever you actually sense a 1.27 MeV +gamma ray followed by to 511 K V's here + + align:start position:0% +gamma ray followed by to 511 K V's here + + + align:start position:0% +gamma ray followed by to 511 K V's here +then you know you've had a positron + + align:start position:0% +then you know you've had a positron + + + align:start position:0% +then you know you've had a positron +annihilation event and you can actually + + align:start position:0% +annihilation event and you can actually + + + align:start position:0% +annihilation event and you can actually +count the time between when those things + + align:start position:0% +count the time between when those things + + + align:start position:0% +count the time between when those things +happened and you can see the number of + + align:start position:0% +happened and you can see the number of + + + align:start position:0% +happened and you can see the number of +counts and get the average positron + + align:start position:0% +counts and get the average positron + + + align:start position:0% +counts and get the average positron +lifetime from finding out how many + + align:start position:0% +lifetime from finding out how many + + + align:start position:0% +lifetime from finding out how many +counts you get every five Pico seconds + + align:start position:0% +counts you get every five Pico seconds + + + align:start position:0% +counts you get every five Pico seconds +for example there's something to note + + align:start position:0% +for example there's something to note + + + align:start position:0% +for example there's something to note +about these counting spectra anybody + + align:start position:0% +about these counting spectra anybody + + + align:start position:0% +about these counting spectra anybody +know why they're so smooth up here and + + align:start position:0% +know why they're so smooth up here and + + + align:start position:0% +know why they're so smooth up here and +then they're so delineating down here + + align:start position:0% +then they're so delineating down here + + + align:start position:0% +then they're so delineating down here +anyone have an idea you're gonna see + + align:start position:0% +anyone have an idea you're gonna see + + + align:start position:0% +anyone have an idea you're gonna see +this a lot in 2209 when you actually + + align:start position:0% +this a lot in 2209 when you actually + + + align:start position:0% +this a lot in 2209 when you actually +count beta particles or alpha particles + + align:start position:0% +count beta particles or alpha particles + + + align:start position:0% +count beta particles or alpha particles +and you're counting statistics get a + + align:start position:0% +and you're counting statistics get a + + + align:start position:0% +and you're counting statistics get a +little crappier this is a log scale of + + align:start position:0% +little crappier this is a log scale of + + + align:start position:0% +little crappier this is a log scale of +counts or in this case counts per 5 Pico + + align:start position:0% +counts or in this case counts per 5 Pico + + + align:start position:0% +counts or in this case counts per 5 Pico +seconds 10 to the 0 is better known as 1 + + align:start position:0% +seconds 10 to the 0 is better known as 1 + + + align:start position:0% +seconds 10 to the 0 is better known as 1 +so you're looking at one count or two or + + align:start position:0% +so you're looking at one count or two or + + + align:start position:0% +so you're looking at one count or two or +three you're looking at the discrete + + align:start position:0% +three you're looking at the discrete + + + align:start position:0% +three you're looking at the discrete +events you can't have one-and-a-half + + align:start position:0% +events you can't have one-and-a-half + + + align:start position:0% +events you can't have one-and-a-half +counts so you're gonna see this kind of + + align:start position:0% +counts so you're gonna see this kind of + + + align:start position:0% +counts so you're gonna see this kind of +thing quite a lot when you're trying to + + align:start position:0% +thing quite a lot when you're trying to + + + align:start position:0% +thing quite a lot when you're trying to +count very rare events and if you're + + align:start position:0% +count very rare events and if you're + + + align:start position:0% +count very rare events and if you're +down in that down in the weeds like this + + align:start position:0% +down in that down in the weeds like this + + + align:start position:0% +down in that down in the weeds like this +let's just say your statistics aren't + + align:start position:0% +let's just say your statistics aren't + + + align:start position:0% +let's just say your statistics aren't +that good but since this is a + + align:start position:0% +that good but since this is a + + + align:start position:0% +that good but since this is a +logarithmic scale 10 to the fourth is + + align:start position:0% +logarithmic scale 10 to the fourth is + + + align:start position:0% +logarithmic scale 10 to the fourth is +better known as 10,000 that's enough to + + align:start position:0% +better known as 10,000 that's enough to + + + align:start position:0% +better known as 10,000 that's enough to +get good statistics and fit a nice curve + + align:start position:0% +get good statistics and fit a nice curve + + + align:start position:0% +get good statistics and fit a nice curve +to this positron lifetime thing this is + + align:start position:0% +to this positron lifetime thing this is + + + align:start position:0% +to this positron lifetime thing this is +what one of them actually looks like and + + align:start position:0% +what one of them actually looks like and + + + align:start position:0% +what one of them actually looks like and +you can kind of tell right there's the + + align:start position:0% +you can kind of tell right there's the + + + align:start position:0% +you can kind of tell right there's the +big inside there is where all the + + align:start position:0% +big inside there is where all the + + + align:start position:0% +big inside there is where all the +positrons are coming out so that's + + align:start position:0% +positrons are coming out so that's + + + align:start position:0% +positrons are coming out so that's +probably lead shielding here's two + + align:start position:0% +probably lead shielding here's two + + + align:start position:0% +probably lead shielding here's two +detectors on either side and here's + + align:start position:0% +detectors on either side and here's + + + align:start position:0% +detectors on either side and here's +another detector to detect that + + align:start position:0% +another detector to detect that + + + align:start position:0% +another detector to detect that +1.27 mev birth gamma-ray so if you get + + align:start position:0% +1.27 mev birth gamma-ray so if you get + + + align:start position:0% +1.27 mev birth gamma-ray so if you get +those three events happening all in the + + align:start position:0% +those three events happening all in the + + + align:start position:0% +those three events happening all in the +right time you've got a positive event + + align:start position:0% +right time you've got a positive event + + + align:start position:0% +right time you've got a positive event +that you can count and last thing I'll + + align:start position:0% +that you can count and last thing I'll + + + align:start position:0% +that you can count and last thing I'll +mention is you can actually use this + + align:start position:0% +mention is you can actually use this + + + align:start position:0% +mention is you can actually use this +like I said to gut not just a number of + + align:start position:0% +like I said to gut not just a number of + + + align:start position:0% +like I said to gut not just a number of +vacancies but the number of different + + align:start position:0% +vacancies but the number of different + + + align:start position:0% +vacancies but the number of different +size defects you might have two or three + + align:start position:0% +size defects you might have two or three + + + align:start position:0% +size defects you might have two or three +missing atoms next to each other + + align:start position:0% +missing atoms next to each other + + + align:start position:0% +missing atoms next to each other +which will have different positron + + align:start position:0% +which will have different positron + + + align:start position:0% +which will have different positron +lifetimes and you can actually count the + + align:start position:0% +lifetimes and you can actually count the + + + align:start position:0% +lifetimes and you can actually count the +number of each of these to get the + + align:start position:0% +number of each of these to get the + + + align:start position:0% +number of each of these to get the +diameter or the size of these atomic + + align:start position:0% +diameter or the size of these atomic + + + align:start position:0% +diameter or the size of these atomic +defects and this is one of the ways of + + align:start position:0% +defects and this is one of the ways of + + + align:start position:0% +defects and this is one of the ways of +confirming our models of radiation + + align:start position:0% +confirming our models of radiation + + + align:start position:0% +confirming our models of radiation +damage which is like all I do that's + + align:start position:0% +damage which is like all I do that's + + + align:start position:0% +damage which is like all I do that's +half of our group if you want to read + + align:start position:0% +half of our group if you want to read + + + align:start position:0% +half of our group if you want to read +anything more about positron + + align:start position:0% +anything more about positron + + + align:start position:0% +anything more about positron +annihilation spectroscopy all the stuff + + align:start position:0% +annihilation spectroscopy all the stuff + + + align:start position:0% +annihilation spectroscopy all the stuff +in these slides were from these + + align:start position:0% +in these slides were from these + + + align:start position:0% +in these slides were from these +references which you can look up easily + + align:start position:0% +references which you can look up easily + + + align:start position:0% +references which you can look up easily +on the MIT libraries we have access to + + align:start position:0% +on the MIT libraries we have access to + + + align:start position:0% +on the MIT libraries we have access to +everything because that's MIT we just + + align:start position:0% +everything because that's MIT we just + + + align:start position:0% +everything because that's MIT we just +buy everything there is so I'd encourage + + align:start position:0% +buy everything there is so I'd encourage + + + align:start position:0% +buy everything there is so I'd encourage +you to look here if you want to see more + + align:start position:0% +you to look here if you want to see more + + + align:start position:0% +you to look here if you want to see more +details on how this works and why it + + align:start position:0% +details on how this works and why it + + + align:start position:0% +details on how this works and why it +works so because it's exactly ten of + + align:start position:0% +works so because it's exactly ten of + + + align:start position:0% +works so because it's exactly ten of +tenna + + align:start position:0% +tenna + + + align:start position:0% +tenna +or five of five of I want to open it up + + align:start position:0% +or five of five of I want to open it up + + + align:start position:0% +or five of five of I want to open it up +to any questions on alpha decay beta + + align:start position:0% +to any questions on alpha decay beta + + + align:start position:0% +to any questions on alpha decay beta +decay positron decay or the decay + + align:start position:0% +decay positron decay or the decay + + + align:start position:0% +decay positron decay or the decay +diagrams that we've developed today yes + + align:start position:0% +diagrams that we've developed today yes + + + align:start position:0% +diagrams that we've developed today yes +what is the most dangerous kind of decay + + align:start position:0% +what is the most dangerous kind of decay + + + align:start position:0% +what is the most dangerous kind of decay +to be exposed to so in this case you'd + + align:start position:0% +to be exposed to so in this case you'd + + + align:start position:0% +to be exposed to so in this case you'd +want to say the energy of the particle + + align:start position:0% +want to say the energy of the particle + + + align:start position:0% +want to say the energy of the particle +is held constant and the number of those + + align:start position:0% +is held constant and the number of those + + + align:start position:0% +is held constant and the number of those +particles is held constant and actually + + align:start position:0% +particles is held constant and actually + + + align:start position:0% +particles is held constant and actually +we're going to answer this question when + + align:start position:0% +we're going to answer this question when + + + align:start position:0% +we're going to answer this question when +we get to medical and biological effects + + align:start position:0% +we get to medical and biological effects + + + align:start position:0% +we get to medical and biological effects +but let's do a little flash board now + + align:start position:0% +but let's do a little flash board now + + + align:start position:0% +but let's do a little flash board now +let's assume if you want to see which + + align:start position:0% +let's assume if you want to see which + + + align:start position:0% +let's assume if you want to see which +one of these decays is most dangerous + + align:start position:0% +one of these decays is most dangerous + + + align:start position:0% +one of these decays is most dangerous +we'll have to say constant constant + + align:start position:0% +we'll have to say constant constant + + + align:start position:0% +we'll have to say constant constant +energy of decay constant activity and + + align:start position:0% +energy of decay constant activity and + + + align:start position:0% +energy of decay constant activity and +what else can we hold constant well + + align:start position:0% +what else can we hold constant well + + + align:start position:0% +what else can we hold constant well +constant you let's say the same number + + align:start position:0% +constant you let's say the same number + + + align:start position:0% +constant you let's say the same number +of particles end up hitting you that + + align:start position:0% +of particles end up hitting you that + + + align:start position:0% +of particles end up hitting you that +depends on whether they're inside or + + align:start position:0% +depends on whether they're inside or + + + align:start position:0% +depends on whether they're inside or +outside your body if you were to ingest + + align:start position:0% +outside your body if you were to ingest + + + align:start position:0% +outside your body if you were to ingest +material then alphas would be your worst + + align:start position:0% +material then alphas would be your worst + + + align:start position:0% +material then alphas would be your worst +because alpha particles are massive and + + align:start position:0% +because alpha particles are massive and + + + align:start position:0% +because alpha particles are massive and +charged nuclei which means they interact + + align:start position:0% +charged nuclei which means they interact + + + align:start position:0% +charged nuclei which means they interact +very strong + + align:start position:0% +very strong + + + align:start position:0% +very strong +with matter around them so if you ingest + + align:start position:0% +with matter around them so if you ingest + + + align:start position:0% +with matter around them so if you ingest +them and they end up incorporating into + + align:start position:0% +them and they end up incorporating into + + + align:start position:0% +them and they end up incorporating into +your cells where they can just get next + + align:start position:0% +your cells where they can just get next + + + align:start position:0% +your cells where they can just get next +to DNA they can just blast it apart + + align:start position:0% +to DNA they can just blast it apart + + + align:start position:0% +to DNA they can just blast it apart +however an alpha source of equal + + align:start position:0% +however an alpha source of equal + + + align:start position:0% +however an alpha source of equal +strength held in your hand would do + + align:start position:0% +strength held in your hand would do + + + align:start position:0% +strength held in your hand would do +nothing the dead skin cells are enough + + align:start position:0% +nothing the dead skin cells are enough + + + align:start position:0% +nothing the dead skin cells are enough +to stop alpha particles and we're gonna + + align:start position:0% +to stop alpha particles and we're gonna + + + align:start position:0% +to stop alpha particles and we're gonna +find out exactly why when we look at the + + align:start position:0% +find out exactly why when we look at the + + + align:start position:0% +find out exactly why when we look at the +range and stopping power of different + + align:start position:0% +range and stopping power of different + + + align:start position:0% +range and stopping power of different +particles and matter from the outside + + align:start position:0% +particles and matter from the outside + + + align:start position:0% +particles and matter from the outside +alphas won't really get through your + + align:start position:0% +alphas won't really get through your + + + align:start position:0% +alphas won't really get through your +skin betas might get through a little + + align:start position:0% +skin betas might get through a little + + + align:start position:0% +skin betas might get through a little +bit of your skin but not much gamma rays + + align:start position:0% +bit of your skin but not much gamma rays + + + align:start position:0% +bit of your skin but not much gamma rays +will mostly go right through you it's + + align:start position:0% +will mostly go right through you it's + + + align:start position:0% +will mostly go right through you it's +neutrons that are the real killers says + + align:start position:0% +neutrons that are the real killers says + + + align:start position:0% +neutrons that are the real killers says +neutrons are heavy but uncharged so they + + align:start position:0% +neutrons are heavy but uncharged so they + + + align:start position:0% +neutrons are heavy but uncharged so they +interact kind of strongly when they do + + align:start position:0% +interact kind of strongly when they do + + + align:start position:0% +interact kind of strongly when they do +hit they pack a wallop and they do a lot + + align:start position:0% +hit they pack a wallop and they do a lot + + + align:start position:0% +hit they pack a wallop and they do a lot +of damage and they're mean free path and + + align:start position:0% +of damage and they're mean free path and + + + align:start position:0% +of damage and they're mean free path and +you is on the order of 10 centimeters so + + align:start position:0% +you is on the order of 10 centimeters so + + + align:start position:0% +you is on the order of 10 centimeters so +a neutron source from the outside can do + + align:start position:0% +a neutron source from the outside can do + + + align:start position:0% +a neutron source from the outside can do +a lot of damage from the outside the + + align:start position:0% +a lot of damage from the outside the + + + align:start position:0% +a lot of damage from the outside the +alphas and the beta's would be stopped + + align:start position:0% +alphas and the beta's would be stopped + + + align:start position:0% +alphas and the beta's would be stopped +by your skin and clothes the gamma rays + + align:start position:0% +by your skin and clothes the gamma rays + + + align:start position:0% +by your skin and clothes the gamma rays +almost all of them will go right through + + align:start position:0% +almost all of them will go right through + + + align:start position:0% +almost all of them will go right through +you and you guys will actually have to + + align:start position:0% +you and you guys will actually have to + + + align:start position:0% +you and you guys will actually have to +do this calculation to find out how many + + align:start position:0% +do this calculation to find out how many + + + align:start position:0% +do this calculation to find out how many +gamma rays would you absorb from a gamma + + align:start position:0% +gamma rays would you absorb from a gamma + + + align:start position:0% +gamma rays would you absorb from a gamma +ray emission and how many go right + + align:start position:0% +ray emission and how many go right + + + align:start position:0% +ray emission and how many go right +through you the hint is most of them get + + align:start position:0% +through you the hint is most of them get + + + align:start position:0% +through you the hint is most of them get +out so there's a there's an exam + + align:start position:0% +out so there's a there's an exam + + + align:start position:0% +out so there's a there's an exam +question we used to ask in 2201 that I + + align:start position:0% +question we used to ask in 2201 that I + + + align:start position:0% +question we used to ask in 2201 that I +was asked during the first exam is + + align:start position:0% +was asked during the first exam is + + + align:start position:0% +was asked during the first exam is +you've got four cookies an alpha emitter + + align:start position:0% +you've got four cookies an alpha emitter + + + align:start position:0% +you've got four cookies an alpha emitter +a beta emitter a gamma emitter and a + + align:start position:0% +a beta emitter a gamma emitter and a + + + align:start position:0% +a beta emitter a gamma emitter and a +neutron emitter of constant energy and + + align:start position:0% +neutron emitter of constant energy and + + + align:start position:0% +neutron emitter of constant energy and +activity you must do one of the + + align:start position:0% +activity you must do one of the + + + align:start position:0% +activity you must do one of the +following you have to hold one in your + + align:start position:0% +following you have to hold one in your + + + align:start position:0% +following you have to hold one in your +hand at arm's length you have to put one + + align:start position:0% +hand at arm's length you have to put one + + + align:start position:0% +hand at arm's length you have to put one +in your pocket you have to eat one and + + align:start position:0% +in your pocket you have to eat one and + + + align:start position:0% +in your pocket you have to eat one and +you have to give one to a friend what do + + align:start position:0% +you have to give one to a friend what do + + + align:start position:0% +you have to give one to a friend what do +you do and why anyone have an idea + + align:start position:0% + + + + align:start position:0% + +pop quiz yeah + + align:start position:0% + + + + align:start position:0% + +that's right I can tell this is the West + + align:start position:0% +that's right I can tell this is the West + + + align:start position:0% +that's right I can tell this is the West +because when I asked a group of + + align:start position:0% +because when I asked a group of + + + align:start position:0% +because when I asked a group of +Singaporean students the same question + + align:start position:0% +Singaporean students the same question + + + align:start position:0% +Singaporean students the same question +they would eat the neutron to save the + + align:start position:0% +they would eat the neutron to save the + + + align:start position:0% +they would eat the neutron to save the +friend because of Confucian ethics yeah + + align:start position:0% +friend because of Confucian ethics yeah + + + align:start position:0% +friend because of Confucian ethics yeah +I doesn't fly here your answer is + + align:start position:0% +I doesn't fly here your answer is + + + align:start position:0% +I doesn't fly here your answer is +correct because this is America what + + align:start position:0% +correct because this is America what + + + align:start position:0% +correct because this is America what +would you do with the other three eat + + align:start position:0% +would you do with the other three eat + + + align:start position:0% +would you do with the other three eat +the gamma because most of the gammas + + align:start position:0% +the gamma because most of the gammas + + + align:start position:0% +the gamma because most of the gammas +will just get to the friend right what + + align:start position:0% +will just get to the friend right what + + + align:start position:0% +will just get to the friend right what +about the Alpha and the beta yep hold + + align:start position:0% +about the Alpha and the beta yep hold + + + align:start position:0% +about the Alpha and the beta yep hold +the beta at arm's length because there's + + align:start position:0% +the beta at arm's length because there's + + + align:start position:0% +the beta at arm's length because there's +another aspect of shielding betas that + + align:start position:0% +another aspect of shielding betas that + + + align:start position:0% +another aspect of shielding betas that +we'll get into when betas stop in + + align:start position:0% +we'll get into when betas stop in + + + align:start position:0% +we'll get into when betas stop in +material they produce some low energy + + align:start position:0% +material they produce some low energy + + + align:start position:0% +material they produce some low energy +x-rays called bremsstrahlung so you'd + + align:start position:0% +x-rays called bremsstrahlung so you'd + + + align:start position:0% +x-rays called bremsstrahlung so you'd +want to get those far from you and the + + align:start position:0% +want to get those far from you and the + + + align:start position:0% +want to get those far from you and the +Alpha in your pocket we'll just be + + align:start position:0% +Alpha in your pocket we'll just be + + + align:start position:0% +Alpha in your pocket we'll just be +absorbed by the pocket yeah so that's + + align:start position:0% +absorbed by the pocket yeah so that's + + + align:start position:0% +absorbed by the pocket yeah so that's +the right question so you're not gonna + + align:start position:0% +the right question so you're not gonna + + + align:start position:0% +the right question so you're not gonna +see that on the exam but good news is + + align:start position:0% +see that on the exam but good news is + + + align:start position:0% +see that on the exam but good news is +you've pretty much got the right answer + + align:start position:0% +you've pretty much got the right answer + + + align:start position:0% +you've pretty much got the right answer +because this is America probably time + + align:start position:0% +because this is America probably time + + + align:start position:0% +because this is America probably time +for one more question if anyone has one + + align:start position:0% + + + + align:start position:0% + +cool if not then I want to remind you + + align:start position:0% +cool if not then I want to remind you + + + align:start position:0% +cool if not then I want to remind you +Amelia + + align:start position:0% +Amelia + + + align:start position:0% +Amelia +we'll see you on Thursday so do come to + + align:start position:0% +we'll see you on Thursday so do come to + + + align:start position:0% +we'll see you on Thursday so do come to +class Thursday I'm gonna change the + + align:start position:0% +class Thursday I'm gonna change the + + + align:start position:0% +class Thursday I'm gonna change the +syllabus to reflect that and we'll have + + align:start position:0% +syllabus to reflect that and we'll have + + + align:start position:0% +syllabus to reflect that and we'll have +two hours of class on Friday to get + + align:start position:0% +two hours of class on Friday to get + + + align:start position:0% +two hours of class on Friday to get +through decay and activity in half-life + + align:start position:0% +through decay and activity in half-life + + + align:start position:0% +through decay and activity in half-life +followed by an hour of recitation so I + + align:start position:0% +followed by an hour of recitation so I + + + align:start position:0% +followed by an hour of recitation so I +will see you guys Friday and we'll see + + align:start position:0% +will see you guys Friday and we'll see + + + align:start position:0% +will see you guys Friday and we'll see +what mood I'm in depending on how the + + align:start position:0% +what mood I'm in depending on how the + + + align:start position:0% +what mood I'm in depending on how the +nano caliber entry goes could be a fun + + align:start position:0% +nano caliber entry goes could be a fun + + + align:start position:0% +nano caliber entry goes could be a fun +measurement + + align:start position:0% + + + + align:start position:0% + +you \ No newline at end of file diff --git a/YWxY6mZwRSQ.txt b/YWxY6mZwRSQ.txt new file mode 100644 index 0000000000000000000000000000000000000000..8dcd943d4cd646e3b8f3c954a2caa05b13bd4dc4 --- /dev/null +++ b/YWxY6mZwRSQ.txt @@ -0,0 +1,2963 @@ +align:start position:0% + +two particles is interesting many cases + + align:start position:0% +two particles is interesting many cases + + + align:start position:0% +two particles is interesting many cases +but in order to see what really is + + align:start position:0% +but in order to see what really is + + + align:start position:0% +but in order to see what really is +happening and how much structure you + + align:start position:0% +happening and how much structure you + + + align:start position:0% +happening and how much structure you +have to go to more than two particles to + + align:start position:0% +have to go to more than two particles to + + + align:start position:0% +have to go to more than two particles to +party this is a little too special it's + + align:start position:0% +party this is a little too special it's + + + align:start position:0% +party this is a little too special it's +so we need to go beyond two particles + + align:start position:0% +so we need to go beyond two particles + + + align:start position:0% +so we need to go beyond two particles +and see what happens with this operator + + align:start position:0% +and see what happens with this operator + + + align:start position:0% +and see what happens with this operator +so I'll do that so we'll add more + + align:start position:0% +so I'll do that so we'll add more + + + align:start position:0% +so I'll do that so we'll add more +particles so let's do that so if you + + align:start position:0% +particles so let's do that so if you + + + align:start position:0% +particles so let's do that so if you +have n particles and particles capital n + + align:start position:0% +have n particles and particles capital n + + + align:start position:0% +have n particles and particles capital n +we can consider also permutations and + + align:start position:0% +we can consider also permutations and + + + align:start position:0% +we can consider also permutations and +how many permutations are you gonna have + + align:start position:0% +how many permutations are you gonna have + + + align:start position:0% +how many permutations are you gonna have +you're gonna have n factorial + + align:start position:0% +you're gonna have n factorial + + + align:start position:0% +you're gonna have n factorial +permutations in notation of Hilbert + + align:start position:0% +permutations in notation of Hilbert + + + align:start position:0% +permutations in notation of Hilbert +space n factorial permutations operators + + align:start position:0% +space n factorial permutations operators + + + align:start position:0% +space n factorial permutations operators +so why is n factorial because a + + align:start position:0% +so why is n factorial because a + + + align:start position:0% +so why is n factorial because a +permutation is a reordering of your n + + align:start position:0% +permutation is a reordering of your n + + + align:start position:0% +permutation is a reordering of your n +objects and therefore in order to define + + align:start position:0% +objects and therefore in order to define + + + align:start position:0% +objects and therefore in order to define +a reordering you must decide which + + align:start position:0% +a reordering you must decide which + + + align:start position:0% +a reordering you must decide which +object is going to be the new first you + + align:start position:0% +object is going to be the new first you + + + align:start position:0% +object is going to be the new first you +have your n objects there so you have n + + align:start position:0% +have your n objects there so you have n + + + align:start position:0% +have your n objects there so you have n +choices to pick a first and n minus 1 + + align:start position:0% +choices to pick a first and n minus 1 + + + align:start position:0% +choices to pick a first and n minus 1 +choices to pick a second and minus 2 so + + align:start position:0% +choices to pick a second and minus 2 so + + + align:start position:0% +choices to pick a second and minus 2 so +n factorial is the number of + + align:start position:0% +n factorial is the number of + + + align:start position:0% +n factorial is the number of +permutations the permutations form a + + align:start position:0% +permutations the permutations form a + + + align:start position:0% +permutations the permutations form a +group so the permutations of n objects + + align:start position:0% + + + + align:start position:0% + +form the symmetric group group s capital + + align:start position:0% +form the symmetric group group s capital + + + align:start position:0% +form the symmetric group group s capital +n with + + align:start position:0% +n with + + + align:start position:0% +n with +n-factorial elements just like you study + + align:start position:0% +n-factorial elements just like you study + + + align:start position:0% +n-factorial elements just like you study +the group su 2 of two-by-two unitary + + align:start position:0% +the group su 2 of two-by-two unitary + + + align:start position:0% +the group su 2 of two-by-two unitary +matrices or the group so3 of + + align:start position:0% +matrices or the group so3 of + + + align:start position:0% +matrices or the group so3 of +3-dimensional rotations in space the + + align:start position:0% +3-dimensional rotations in space the + + + align:start position:0% +3-dimensional rotations in space the +permutation group is a group that + + align:start position:0% +permutation group is a group that + + + align:start position:0% +permutation group is a group that +deserves a lot of study it's a finite + + align:start position:0% +deserves a lot of study it's a finite + + + align:start position:0% +deserves a lot of study it's a finite +discrete group is not a continuous group + + align:start position:0% +discrete group is not a continuous group + + + align:start position:0% +discrete group is not a continuous group +of transformations is discrete + + align:start position:0% +of transformations is discrete + + + align:start position:0% +of transformations is discrete +transformations and they do funny things + + align:start position:0% +transformations and they do funny things + + + align:start position:0% +transformations and they do funny things +so we need to understand this group so + + align:start position:0% +so we need to understand this group so + + + align:start position:0% +so we need to understand this group so +let's describe the notation of what is a + + align:start position:0% +let's describe the notation of what is a + + + align:start position:0% +let's describe the notation of what is a +permutation suppose you have n equal 4 4 + + align:start position:0% +permutation suppose you have n equal 4 4 + + + align:start position:0% +permutation suppose you have n equal 4 4 +particles so a given state is + + align:start position:0% +particles so a given state is + + + align:start position:0% +particles so a given state is +represented by a b c d and you could say + + align:start position:0% +represented by a b c d and you could say + + + align:start position:0% +represented by a b c d and you could say +this is the first particle 2nd 3rd and + + align:start position:0% +this is the first particle 2nd 3rd and + + + align:start position:0% +this is the first particle 2nd 3rd and +4th and these are the states and now + + align:start position:0% +4th and these are the states and now + + + align:start position:0% +4th and these are the states and now +we're gonna write the perturbation the + + align:start position:0% +we're gonna write the perturbation the + + + align:start position:0% +we're gonna write the perturbation the +best thing I think is just doing example + + align:start position:0% +best thing I think is just doing example + + + align:start position:0% +best thing I think is just doing example +3 3 1 4 2 so a permutation now has + + align:start position:0% +3 3 1 4 2 so a permutation now has + + + align:start position:0% +3 3 1 4 2 so a permutation now has +capital n labels so for labels and this + + align:start position:0% +capital n labels so for labels and this + + + align:start position:0% +capital n labels so for labels and this +is a permutation acting on this state + + align:start position:0% +is a permutation acting on this state + + + align:start position:0% +is a permutation acting on this state +remember the to one permutation exchange + + align:start position:0% +remember the to one permutation exchange + + + align:start position:0% +remember the to one permutation exchange +the state in two was put in 1 the state + + align:start position:0% +the state in two was put in 1 the state + + + align:start position:0% +the state in two was put in 1 the state +in one was put in to here is the + + align:start position:0% +in one was put in to here is the + + + align:start position:0% +in one was put in to here is the +instruction so the instruction is put in + + align:start position:0% +instruction so the instruction is put in + + + align:start position:0% +instruction so the instruction is put in +position 1 the third state so here it + + align:start position:0% +position 1 the third state so here it + + + align:start position:0% +position 1 the third state so here it +says 3 so the third state goes into the + + align:start position:0% +says 3 so the third state goes into the + + + align:start position:0% +says 3 so the third state goes into the +first position so that's the first + + align:start position:0% +first position so that's the first + + + align:start position:0% +first position so that's the first +position + + align:start position:0% + + + + align:start position:0% + +the first date goes into the second + + align:start position:0% +the first date goes into the second + + + align:start position:0% +the first date goes into the second +position the fourth state goes into the + + align:start position:0% +position the fourth state goes into the + + + align:start position:0% +position the fourth state goes into the +third position the third in that's here + + align:start position:0% +third position the third in that's here + + + align:start position:0% +third position the third in that's here +so the third position is now occupied by + + align:start position:0% +so the third position is now occupied by + + + align:start position:0% +so the third position is now occupied by +the fourth state D and the second state + + align:start position:0% +the fourth state D and the second state + + + align:start position:0% +the fourth state D and the second state +goes into the fourth position so this is + + align:start position:0% +goes into the fourth position so this is + + + align:start position:0% +goes into the fourth position so this is +the way we are going to define + + align:start position:0% +the way we are going to define + + + align:start position:0% +the way we are going to define +perturbation permutations people define + + align:start position:0% +perturbation permutations people define + + + align:start position:0% +perturbation permutations people define +them in different ways and you have to + + align:start position:0% +them in different ways and you have to + + + align:start position:0% +them in different ways and you have to +be sure you know what it means but I'll + + align:start position:0% +be sure you know what it means but I'll + + + align:start position:0% +be sure you know what it means but I'll +write this this means put third object + + align:start position:0% +write this this means put third object + + + align:start position:0% +write this this means put third object +in first position here the second one + + align:start position:0% +in first position here the second one + + + align:start position:0% +in first position here the second one +let's write put first object in second + + align:start position:0% +let's write put first object in second + + + align:start position:0% +let's write put first object in second +position + + align:start position:0% + + + + align:start position:0% + +so it's it's nice to have this notation + + align:start position:0% +so it's it's nice to have this notation + + + align:start position:0% +so it's it's nice to have this notation +because now you can understand how the + + align:start position:0% +because now you can understand how the + + + align:start position:0% +because now you can understand how the +group works a group of transformations + + align:start position:0% +group works a group of transformations + + + align:start position:0% +group works a group of transformations +this is a set of elements that can be + + align:start position:0% +this is a set of elements that can be + + + align:start position:0% +this is a set of elements that can be +multiplied there is an identity and + + align:start position:0% +multiplied there is an identity and + + + align:start position:0% +multiplied there is an identity and +things have inverses as well so + + align:start position:0% +things have inverses as well so + + + align:start position:0% +things have inverses as well so +permutations have inverses if you + + align:start position:0% +permutations have inverses if you + + + align:start position:0% +permutations have inverses if you +rearrange the objects in one way you can + + align:start position:0% +rearrange the objects in one way you can + + + align:start position:0% +rearrange the objects in one way you can +rearrange them back so for example what + + align:start position:0% +rearrange them back so for example what + + + align:start position:0% +rearrange them back so for example what +would be the inverse of this permutation + + align:start position:0% +would be the inverse of this permutation + + + align:start position:0% +would be the inverse of this permutation +I try to figure out what is the inverse + + align:start position:0% +I try to figure out what is the inverse + + + align:start position:0% +I try to figure out what is the inverse +inverse of P 3 1 4 2 so I look at this + + align:start position:0% +inverse of P 3 1 4 2 so I look at this + + + align:start position:0% +inverse of P 3 1 4 2 so I look at this +thing and I think of what is the + + align:start position:0% +thing and I think of what is the + + + align:start position:0% +thing and I think of what is the +instruction that I must put in order to + + align:start position:0% +instruction that I must put in order to + + + align:start position:0% +instruction that I must put in order to +rearrange back this series and I say + + align:start position:0% +rearrange back this series and I say + + + align:start position:0% +rearrange back this series and I say +well I must put the 2nd back in position + + align:start position:0% +well I must put the 2nd back in position + + + align:start position:0% +well I must put the 2nd back in position +1 so there should be a p2 here I should + + align:start position:0% +1 so there should be a p2 here I should + + + align:start position:0% +1 so there should be a p2 here I should +put the 4th in position 2 and then I + + align:start position:0% +put the 4th in position 2 and then I + + + align:start position:0% +put the 4th in position 2 and then I +should put the first in position 3 first + + align:start position:0% +should put the first in position 3 first + + + align:start position:0% +should put the first in position 3 first +in position 3 and I should put the 3rd + + align:start position:0% +in position 3 and I should put the 3rd + + + align:start position:0% +in position 3 and I should put the 3rd +in position 4 so I claim that is the + + align:start position:0% +in position 4 so I claim that is the + + + align:start position:0% +in position 4 so I claim that is the +inverse of this operator P 2 1 3 is the + + align:start position:0% +inverse of this operator P 2 1 3 is the + + + align:start position:0% +inverse of this operator P 2 1 3 is the +inverse of this is so you can check it + + align:start position:0% +inverse of this is so you can check it + + + align:start position:0% +inverse of this is so you can check it +again P 2 2 + + align:start position:0% +again P 2 2 + + + align:start position:0% +again P 2 2 +for 1/3 times p3 1 for 2 you just do it + + align:start position:0% +for 1/3 times p3 1 for 2 you just do it + + + align:start position:0% +for 1/3 times p3 1 for 2 you just do it +on a b c b well the first one you + + align:start position:0% +on a b c b well the first one you + + + align:start position:0% +on a b c b well the first one you +already know is 2 for 1 3 is put the + + align:start position:0% +already know is 2 for 1 3 is put the + + + align:start position:0% +already know is 2 for 1 3 is put the +third in 1 put the first in to put the + + align:start position:0% +third in 1 put the first in to put the + + + align:start position:0% +third in 1 put the first in to put the +fourth in 3 and put the second in fourth + + align:start position:0% +fourth in 3 and put the second in fourth + + + align:start position:0% +fourth in 3 and put the second in fourth +B and then it says put the second first + + align:start position:0% +B and then it says put the second first + + + align:start position:0% +B and then it says put the second first +so that's an a put the fourth second B + + align:start position:0% +so that's an a put the fourth second B + + + align:start position:0% +so that's an a put the fourth second B +put the first third C and put the third + + align:start position:0% +put the first third C and put the third + + + align:start position:0% +put the first third C and put the third +fourth B so it's back to the original + + align:start position:0% +fourth B so it's back to the original + + + align:start position:0% +fourth B so it's back to the original +one so indeed it is the inverse so you + + align:start position:0% +one so indeed it is the inverse so you + + + align:start position:0% +one so indeed it is the inverse so you +can ride your permutations and play with + + align:start position:0% +can ride your permutations and play with + + + align:start position:0% +can ride your permutations and play with +them and figure out how to multiply any + + align:start position:0% +them and figure out how to multiply any + + + align:start position:0% +them and figure out how to multiply any +two permutations more generally we write + + align:start position:0% +two permutations more generally we write + + + align:start position:0% +two permutations more generally we write +the permutation as follows suppose you + + align:start position:0% +the permutation as follows suppose you + + + align:start position:0% +the permutation as follows suppose you +have more generally a permutation is + + align:start position:0% +have more generally a permutation is + + + align:start position:0% +have more generally a permutation is +written with some index alpha collective + + align:start position:0% +written with some index alpha collective + + + align:start position:0% +written with some index alpha collective +index alpha that says how the integers 1 + + align:start position:0% +index alpha that says how the integers 1 + + + align:start position:0% +index alpha that says how the integers 1 +up to end our rearranged into alpha of 1 + + align:start position:0% +up to end our rearranged into alpha of 1 + + + align:start position:0% +up to end our rearranged into alpha of 1 +alpha of 2 up to alpha of M so think of + + align:start position:0% +alpha of 2 up to alpha of M so think of + + + align:start position:0% +alpha of 2 up to alpha of M so think of +a permutation taking n integers and + + align:start position:0% +a permutation taking n integers and + + + align:start position:0% +a permutation taking n integers and +rearranging them so the first one the + + align:start position:0% +rearranging them so the first one the + + + align:start position:0% +rearranging them so the first one the +new first index is going to be alpha of + + align:start position:0% +new first index is going to be alpha of + + + align:start position:0% +new first index is going to be alpha of +1 out of 2 and alpha is a rule that + + align:start position:0% +1 out of 2 and alpha is a rule that + + + align:start position:0% +1 out of 2 and alpha is a rule that +takings takes the n integers from 1 + + align:start position:0% +takings takes the n integers from 1 + + + align:start position:0% +takings takes the n integers from 1 +to end and reshuffle them so if you have + + align:start position:0% +to end and reshuffle them so if you have + + + align:start position:0% +to end and reshuffle them so if you have +a state so this is a simple thing + + align:start position:0% +a state so this is a simple thing + + + align:start position:0% +a state so this is a simple thing +because then if you have a P alpha this + + align:start position:0% +because then if you have a P alpha this + + + align:start position:0% +because then if you have a P alpha this +alpha means really P alpha 1 alpha 2 all + + align:start position:0% +alpha means really P alpha 1 alpha 2 all + + + align:start position:0% +alpha means really P alpha 1 alpha 2 all +these things be are for 1 or 2 or 3 or 4 + + align:start position:0% +these things be are for 1 or 2 or 3 or 4 + + + align:start position:0% +these things be are for 1 or 2 or 3 or 4 +if those act on u 1 1 u 2 2 up to u and + + align:start position:0% +if those act on u 1 1 u 2 2 up to u and + + + align:start position:0% +if those act on u 1 1 u 2 2 up to u and +capital m and what does it give you well + + align:start position:0% +capital m and what does it give you well + + + align:start position:0% +capital m and what does it give you well +it says here that you should put the one + + align:start position:0% +it says here that you should put the one + + + align:start position:0% +it says here that you should put the one +that has alpha 1 here on the first + + align:start position:0% +that has alpha 1 here on the first + + + align:start position:0% +that has alpha 1 here on the first +position so you should put first the u + + align:start position:0% +position so you should put first the u + + + align:start position:0% +position so you should put first the u +alpha 1 and then you should put next the + + align:start position:0% +alpha 1 and then you should put next the + + + align:start position:0% +alpha 1 and then you should put next the +u alpha 2 and all the way up to the u + + align:start position:0% +u alpha 2 and all the way up to the u + + + align:start position:0% +u alpha 2 and all the way up to the u +alpha m that's in formulas the rule that + + align:start position:0% +alpha m that's in formulas the rule that + + + align:start position:0% +alpha m that's in formulas the rule that +I was giving you above it tells you how + + align:start position:0% +I was giving you above it tells you how + + + align:start position:0% +I was giving you above it tells you how +to move the state from one to the other + + align:start position:0% + + + + align:start position:0% + +you see if alpha 1 was three it would + + align:start position:0% +you see if alpha 1 was three it would + + + align:start position:0% +you see if alpha 1 was three it would +correspond to take the state u3 and + + align:start position:0% +correspond to take the state u3 and + + + align:start position:0% +correspond to take the state u3 and +putting it first so it's like that + + align:start position:0% +putting it first so it's like that + + + align:start position:0% +putting it first so it's like that +so whatever alpha 1 is whatever number + + align:start position:0% +so whatever alpha 1 is whatever number + + + align:start position:0% +so whatever alpha 1 is whatever number +that state must be pulled into the first + + align:start position:0% +that state must be pulled into the first + + + align:start position:0% +that state must be pulled into the first +kit okay so let's just think a little + + align:start position:0% +kit okay so let's just think a little + + + align:start position:0% +kit okay so let's just think a little +about an example because if it starts + + align:start position:0% +about an example because if it starts + + + align:start position:0% +about an example because if it starts +getting out interesting so let's do + + align:start position:0% +getting out interesting so let's do + + + align:start position:0% +getting out interesting so let's do +three particles for for a little while + + align:start position:0% +three particles for for a little while + + + align:start position:0% +three particles for for a little while +just to see what it is + + align:start position:0% + + + + align:start position:0% + +so three particles and equal three so + + align:start position:0% +so three particles and equal three so + + + align:start position:0% +so three particles and equal three so +what are the permutation operators you + + align:start position:0% +what are the permutation operators you + + + align:start position:0% +what are the permutation operators you +would say P 1 2 3 is what put the first + + align:start position:0% +would say P 1 2 3 is what put the first + + + align:start position:0% +would say P 1 2 3 is what put the first +particle first the second particle + + align:start position:0% +particle first the second particle + + + align:start position:0% +particle first the second particle +second the third particle third doesn't + + align:start position:0% +second the third particle third doesn't + + + align:start position:0% +second the third particle third doesn't +do anything that is the identity so + + align:start position:0% +do anything that is the identity so + + + align:start position:0% +do anything that is the identity so +that's the identity element but then you + + align:start position:0% +that's the identity element but then you + + + align:start position:0% +that's the identity element but then you +could cycle them P 3 2 1 P 2 3 1 these + + align:start position:0% +could cycle them P 3 2 1 P 2 3 1 these + + + align:start position:0% +could cycle them P 3 2 1 P 2 3 1 these +are two more elements this should have + + align:start position:0% +are two more elements this should have + + + align:start position:0% +are two more elements this should have +six elements because it's 3 factorial + + align:start position:0% +six elements because it's 3 factorial + + + align:start position:0% +six elements because it's 3 factorial +and now you have the following 1 P 1 3 2 + + align:start position:0% +and now you have the following 1 P 1 3 2 + + + align:start position:0% +and now you have the following 1 P 1 3 2 +for example that was not in the list you + + align:start position:0% +for example that was not in the list you + + + align:start position:0% +for example that was not in the list you +had the P 1 2 3 now you flip this to be + + align:start position:0% +had the P 1 2 3 now you flip this to be + + + align:start position:0% +had the P 1 2 3 now you flip this to be +1 3 2 if I cycle them P 3 2 1 and P 2 1 + + align:start position:0% +1 3 2 if I cycle them P 3 2 1 and P 2 1 + + + align:start position:0% +1 3 2 if I cycle them P 3 2 1 and P 2 1 +3 these are it + + align:start position:0% +3 these are it + + + align:start position:0% +3 these are it +the middle 1 3 1 2 + + align:start position:0% +the middle 1 3 1 2 + + + align:start position:0% +the middle 1 3 1 2 +yes I was supposed to be cycling them 3 + + align:start position:0% +yes I was supposed to be cycling them 3 + + + align:start position:0% +yes I was supposed to be cycling them 3 +1 2 & 2 3 1 yes + + align:start position:0% +1 2 & 2 3 1 yes + + + align:start position:0% +1 2 & 2 3 1 yes +otherwise I would have repeated that + + align:start position:0% +otherwise I would have repeated that + + + align:start position:0% +otherwise I would have repeated that +good right okay so these are our + + align:start position:0% +good right okay so these are our + + + align:start position:0% +good right okay so these are our +operators and this ones are kind of + + align:start position:0% +operators and this ones are kind of + + + align:start position:0% +operators and this ones are kind of +funny there are simpler ones + + align:start position:0% +funny there are simpler ones + + + align:start position:0% +funny there are simpler ones +please look at them this operator says + + align:start position:0% +please look at them this operator says + + + align:start position:0% +please look at them this operator says +put the first particle in the first + + align:start position:0% +put the first particle in the first + + + align:start position:0% +put the first particle in the first +position so the first particle is left + + align:start position:0% +position so the first particle is left + + + align:start position:0% +position so the first particle is left +unchanged that the 3 & 2 are permuted + + align:start position:0% +unchanged that the 3 & 2 are permuted + + + align:start position:0% +unchanged that the 3 & 2 are permuted +so people sometimes write this they say + + align:start position:0% +so people sometimes write this they say + + + align:start position:0% +so people sometimes write this they say +this permutation operator is just as + + align:start position:0% +this permutation operator is just as + + + align:start position:0% +this permutation operator is just as +transposition 3 2 or 2 3 + + align:start position:0% +transposition 3 2 or 2 3 + + + align:start position:0% +transposition 3 2 or 2 3 +these two are transposed and the first + + align:start position:0% +these two are transposed and the first + + + align:start position:0% +these two are transposed and the first +is left invariant so this can be written + + align:start position:0% +is left invariant so this can be written + + + align:start position:0% +is left invariant so this can be written +as a single transposition in this + + align:start position:0% +as a single transposition in this + + + align:start position:0% +as a single transposition in this +permutation operator a 2 is left + + align:start position:0% +permutation operator a 2 is left + + + align:start position:0% +permutation operator a 2 is left +invariant the second state is copied to + + align:start position:0% +invariant the second state is copied to + + + align:start position:0% +invariant the second state is copied to +the second position but the 1 & 3 are + + align:start position:0% +the second position but the 1 & 3 are + + + align:start position:0% +the second position but the 1 & 3 are +exchanged so this is a transposition of + + align:start position:0% +exchanged so this is a transposition of + + + align:start position:0% +exchanged so this is a transposition of +1 & 3 and in this last permutation + + align:start position:0% +1 & 3 and in this last permutation + + + align:start position:0% +1 & 3 and in this last permutation +operator the third state is left + + align:start position:0% +operator the third state is left + + + align:start position:0% +operator the third state is left +invariant on the third position never + + align:start position:0% +invariant on the third position never + + + align:start position:0% +invariant on the third position never +that as the second is put in first and + + align:start position:0% +that as the second is put in first and + + + align:start position:0% +that as the second is put in first and +the first is put in second so it's a 1 - + + align:start position:0% +the first is put in second so it's a 1 - + + + align:start position:0% +the first is put in second so it's a 1 - +transposition okay so the group has + + align:start position:0% +transposition okay so the group has + + + align:start position:0% +transposition okay so the group has +broken into things that are + + align:start position:0% +broken into things that are + + + align:start position:0% +broken into things that are +transpositions + + align:start position:0% +transpositions + + + align:start position:0% +transpositions +and slightly more complicated things now + + align:start position:0% +and slightly more complicated things now + + + align:start position:0% +and slightly more complicated things now +let's look at the transpositions so + + align:start position:0% +let's look at the transpositions so + + + align:start position:0% +let's look at the transpositions so +these are trans positions and positions + + align:start position:0% + + + + align:start position:0% + +okay what about the transpositions + + align:start position:0% + + + + align:start position:0% + +transpositions are like the permutation + + align:start position:0% +transpositions are like the permutation + + + align:start position:0% +transpositions are like the permutation +operators who were doing before of two + + align:start position:0% +operators who were doing before of two + + + align:start position:0% +operators who were doing before of two +particles you're just changing two + + align:start position:0% +particles you're just changing two + + + align:start position:0% +particles you're just changing two +particles you're leaving the other ones + + align:start position:0% +particles you're leaving the other ones + + + align:start position:0% +particles you're leaving the other ones +unchanged + + align:start position:0% +unchanged + + + align:start position:0% +unchanged +so these transpositions are hermitian + + align:start position:0% +so these transpositions are hermitian + + + align:start position:0% +so these transpositions are hermitian +and unitary positions are hermitian and + + align:start position:0% +and unitary positions are hermitian and + + + align:start position:0% +and unitary positions are hermitian and +unitary just like we had p21 before + + align:start position:0% + + + + align:start position:0% + +now here comes the first statement that + + align:start position:0% +now here comes the first statement that + + + align:start position:0% +now here comes the first statement that +is quite remarkable about this + + align:start position:0% +is quite remarkable about this + + + align:start position:0% +is quite remarkable about this +permutation group any permutation now a + + align:start position:0% +permutation group any permutation now a + + + align:start position:0% +permutation group any permutation now a +claim is the product of some + + align:start position:0% +claim is the product of some + + + align:start position:0% +claim is the product of some +transpositions you see if somebody gives + + align:start position:0% +transpositions you see if somebody gives + + + align:start position:0% +transpositions you see if somebody gives +you a permutation of n integers I think + + align:start position:0% +you a permutation of n integers I think + + + align:start position:0% +you a permutation of n integers I think +you're convinced that by changing two at + + align:start position:0% +you're convinced that by changing two at + + + align:start position:0% +you're convinced that by changing two at +a time you can reach that so that means + + align:start position:0% +a time you can reach that so that means + + + align:start position:0% +a time you can reach that so that means +that with transpositions + + align:start position:0% +that with transpositions + + + align:start position:0% +that with transpositions +you can reach every possible element so + + align:start position:0% +you can reach every possible element so + + + align:start position:0% +you can reach every possible element so +any this is very important any + + align:start position:0% +any this is very important any + + + align:start position:0% +any this is very important any +permutation is the product of + + align:start position:0% + + + + align:start position:0% + +transpositions + + align:start position:0% + + + + align:start position:0% + +and that implies in a sense the main + + align:start position:0% +and that implies in a sense the main + + + align:start position:0% +and that implies in a sense the main +result that you want from operators in + + align:start position:0% +result that you want from operators in + + + align:start position:0% +result that you want from operators in +this Hilbert space since transpositions + + align:start position:0% +this Hilbert space since transpositions + + + align:start position:0% +this Hilbert space since transpositions +are unitary and any permutation is a + + align:start position:0% +are unitary and any permutation is a + + + align:start position:0% +are unitary and any permutation is a +product of transpositions + + align:start position:0% +product of transpositions + + + align:start position:0% +product of transpositions +any permutation is unitary + + align:start position:0% +any permutation is unitary + + + align:start position:0% +any permutation is unitary +so all permutations are unitary + + align:start position:0% + + + + align:start position:0% + +it's not true that all permutations are + + align:start position:0% +it's not true that all permutations are + + + align:start position:0% +it's not true that all permutations are +hermitian you see when you have the + + align:start position:0% +hermitian you see when you have the + + + align:start position:0% +hermitian you see when you have the +product of hermitian operators the + + align:start position:0% +product of hermitian operators the + + + align:start position:0% +product of hermitian operators the +product of hermitian operators is not + + align:start position:0% +product of hermitian operators is not + + + align:start position:0% +product of hermitian operators is not +necessarily hermitian you've seen that + + align:start position:0% +necessarily hermitian you've seen that + + + align:start position:0% +necessarily hermitian you've seen that +if you have two operator hermitian the + + align:start position:0% +if you have two operator hermitian the + + + align:start position:0% +if you have two operator hermitian the +border changes and and the product is + + align:start position:0% +border changes and and the product is + + + align:start position:0% +border changes and and the product is +not hermitian X and P hermitian + + align:start position:0% +not hermitian X and P hermitian + + + align:start position:0% +not hermitian X and P hermitian +operators the product is not hermitian + + align:start position:0% +operators the product is not hermitian + + + align:start position:0% +operators the product is not hermitian +so all permutations are unitary but are + + align:start position:0% +so all permutations are unitary but are + + + align:start position:0% +so all permutations are unitary but are +not hermitian and the third concept that + + align:start position:0% +not hermitian and the third concept that + + + align:start position:0% +not hermitian and the third concept that +comes here Illustrated all in s3 is also + + align:start position:0% +comes here Illustrated all in s3 is also + + + align:start position:0% +comes here Illustrated all in s3 is also +a very fundamental concept we said that + + align:start position:0% +a very fundamental concept we said that + + + align:start position:0% +a very fundamental concept we said that +any permutation is a product of + + align:start position:0% +any permutation is a product of + + + align:start position:0% +any permutation is a product of +transpositions + + align:start position:0% + + + + align:start position:0% + +but it's not a unique product of + + align:start position:0% +but it's not a unique product of + + + align:start position:0% +but it's not a unique product of +transposition in fact you could if you + + align:start position:0% +transposition in fact you could if you + + + align:start position:0% +transposition in fact you could if you +are given some order of objects and + + align:start position:0% +are given some order of objects and + + + align:start position:0% +are given some order of objects and +you're asked to rearrange them by + + align:start position:0% +you're asked to rearrange them by + + + align:start position:0% +you're asked to rearrange them by +transposition you may do them in + + align:start position:0% +transposition you may do them in + + + align:start position:0% +transposition you may do them in +different order so the product is not + + align:start position:0% +different order so the product is not + + + align:start position:0% +different order so the product is not +uniquely determined the product is in + + align:start position:0% +uniquely determined the product is in + + + align:start position:0% +uniquely determined the product is in +fact you could find somebody that does a + + align:start position:0% +fact you could find somebody that does a + + + align:start position:0% +fact you could find somebody that does a +permutation with some number of + + align:start position:0% +permutation with some number of + + + align:start position:0% +permutation with some number of +transpositions + + align:start position:0% +transpositions + + + align:start position:0% +transpositions +and another person with another set of + + align:start position:0% +and another person with another set of + + + align:start position:0% +and another person with another set of +transpositions but one thing that has to + + align:start position:0% +transpositions but one thing that has to + + + align:start position:0% +transpositions but one thing that has to +happen and it's always the same is that + + align:start position:0% +happen and it's always the same is that + + + align:start position:0% +happen and it's always the same is that +the number of transpositions + + align:start position:0% +the number of transpositions + + + align:start position:0% +the number of transpositions +is the same mod 2 that is if you find + + align:start position:0% +is the same mod 2 that is if you find + + + align:start position:0% +is the same mod 2 that is if you find +that to get a permutation you need an + + align:start position:0% +that to get a permutation you need an + + + align:start position:0% +that to get a permutation you need an +even number of transpositions everybody + + align:start position:0% +even number of transpositions everybody + + + align:start position:0% +even number of transpositions everybody +else will need also an even number of + + align:start position:0% +else will need also an even number of + + + align:start position:0% +else will need also an even number of +transpositions if you find an odd number + + align:start position:0% +transpositions if you find an odd number + + + align:start position:0% +transpositions if you find an odd number +of transpositions everybody will find an + + align:start position:0% +of transpositions everybody will find an + + + align:start position:0% +of transpositions everybody will find an +odd + + align:start position:0% +odd + + + align:start position:0% +odd +number of transpositions and that's kind + + align:start position:0% +number of transpositions and that's kind + + + align:start position:0% +number of transpositions and that's kind +of clear if you have if you've achieved + + align:start position:0% +of clear if you have if you've achieved + + + align:start position:0% +of clear if you have if you've achieved +the desired order by doing some number + + align:start position:0% +the desired order by doing some number + + + align:start position:0% +the desired order by doing some number +of trans positions you can add two more + + align:start position:0% +of trans positions you can add two more + + + align:start position:0% +of trans positions you can add two more +trans positions and not change anything + + align:start position:0% +trans positions and not change anything + + + align:start position:0% +trans positions and not change anything +you can flip two objects and flip them + + align:start position:0% +you can flip two objects and flip them + + + align:start position:0% +you can flip two objects and flip them +back so this is a pretty important + + align:start position:0% +back so this is a pretty important + + + align:start position:0% +back so this is a pretty important +result as well so it means that + + align:start position:0% +result as well so it means that + + + align:start position:0% +result as well so it means that +permutations are either even or are odd + + align:start position:0% +permutations are either even or are odd + + + align:start position:0% +permutations are either even or are odd +so permutations are even if built built + + align:start position:0% +so permutations are even if built built + + + align:start position:0% +so permutations are even if built built +built with an even number of trans + + align:start position:0% +built with an even number of trans + + + align:start position:0% +built with an even number of trans +positions and are or odd if built with + + align:start position:0% +positions and are or odd if built with + + + align:start position:0% +positions and are or odd if built with +an odd number of trans positions + + align:start position:0% +an odd number of trans positions + + + align:start position:0% +an odd number of trans positions +so two kinds of permutations even + + align:start position:0% +so two kinds of permutations even + + + align:start position:0% +so two kinds of permutations even +permutations or odd permutations so all + + align:start position:0% +permutations or odd permutations so all + + + align:start position:0% +permutations or odd permutations so all +these things we've kind of seen with the + + align:start position:0% +these things we've kind of seen with the + + + align:start position:0% +these things we've kind of seen with the +this permutation group there's one more + + align:start position:0% +this permutation group there's one more + + + align:start position:0% +this permutation group there's one more +thing that is + + align:start position:0% + + + + align:start position:0% + +necessary to note something that may + + align:start position:0% +necessary to note something that may + + + align:start position:0% +necessary to note something that may +have seemed the coincidence there in + + align:start position:0% +have seemed the coincidence there in + + + align:start position:0% +have seemed the coincidence there in +fact the three on the right are trans + + align:start position:0% +fact the three on the right are trans + + + align:start position:0% +fact the three on the right are trans +positions and they're a single trans + + align:start position:0% +positions and they're a single trans + + + align:start position:0% +positions and they're a single trans +position each so each one of those on + + align:start position:0% +position each so each one of those on + + + align:start position:0% +position each so each one of those on +the right is + + align:start position:0% +the right is + + + align:start position:0% + +an odd permutation it's built with one + + align:start position:0% +an odd permutation it's built with one + + + align:start position:0% +an odd permutation it's built with one +transposition on the other hand the + + align:start position:0% +transposition on the other hand the + + + align:start position:0% +transposition on the other hand the +other ones are even transpositions the + + align:start position:0% +other ones are even transpositions the + + + align:start position:0% +other ones are even transpositions the +first three they the first one is built + + align:start position:0% +first three they the first one is built + + + align:start position:0% +first three they the first one is built +with zero trans positions but the others + + align:start position:0% +with zero trans positions but the others + + + align:start position:0% +with zero trans positions but the others +are built with two trans positions it's + + align:start position:0% +are built with two trans positions it's + + + align:start position:0% +are built with two trans positions it's +something you could just see in detail + + align:start position:0% +something you could just see in detail + + + align:start position:0% +something you could just see in detail +in fact I would say it's worth doing the + + align:start position:0% +in fact I would say it's worth doing the + + + align:start position:0% +in fact I would say it's worth doing the +table of multiplication of this group + + align:start position:0% +table of multiplication of this group + + + align:start position:0% +table of multiplication of this group +but that coincidence is in fact true in + + align:start position:0% +but that coincidence is in fact true in + + + align:start position:0% +but that coincidence is in fact true in +any in SM in the group SM the number of + + align:start position:0% +any in SM in the group SM the number of + + + align:start position:0% +any in SM in the group SM the number of +even permutations is equal to the number + + align:start position:0% +even permutations is equal to the number + + + align:start position:0% +even permutations is equal to the number +of odd permutations some pretty nice + + align:start position:0% +of odd permutations some pretty nice + + + align:start position:0% +of odd permutations some pretty nice +result there's equal numbers of even and + + align:start position:0% +result there's equal numbers of even and + + + align:start position:0% +result there's equal numbers of even and +not permutations in any permutation + + align:start position:0% +not permutations in any permutation + + + align:start position:0% +not permutations in any permutation +group actually it's surprisingly simple + + align:start position:0% +group actually it's surprisingly simple + + + align:start position:0% +group actually it's surprisingly simple +to show that you think of the even + + align:start position:0% +to show that you think of the even + + + align:start position:0% +to show that you think of the even +permutations here here are the even + + align:start position:0% +permutations here here are the even + + + align:start position:0% +permutations here here are the even +permutations and here are the odds + + align:start position:0% +permutations and here are the odds + + + align:start position:0% +permutations and here are the odds +permutations and you can easily show + + align:start position:0% +permutations and you can easily show + + + align:start position:0% +permutations and you can easily show +that there's equal number on this one so + + align:start position:0% +that there's equal number on this one so + + + align:start position:0% +that there's equal number on this one so +let's do it one way is to take the + + align:start position:0% +let's do it one way is to take the + + + align:start position:0% +let's do it one way is to take the +permutation element so suppose you have + + align:start position:0% +permutation element so suppose you have + + + align:start position:0% +permutation element so suppose you have +a permutation how should I call it + + align:start position:0% +a permutation how should I call it + + + align:start position:0% +a permutation how should I call it +p21 you leave everything the same but + + align:start position:0% +p21 you leave everything the same but + + + align:start position:0% +p21 you leave everything the same but +you have p21 that permutes of + + align:start position:0% +you have p21 that permutes of + + + align:start position:0% +you have p21 that permutes of +second and first labels since it's an n + + align:start position:0% +second and first labels since it's an n + + + align:start position:0% +second and first labels since it's an n +group the rest are left in variance of 3 + + align:start position:0% +group the rest are left in variance of 3 + + + align:start position:0% +group the rest are left in variance of 3 +4 5 6 7 8 9 10 and you say this maps any + + align:start position:0% +4 5 6 7 8 9 10 and you say this maps any + + + align:start position:0% +4 5 6 7 8 9 10 and you say this maps any +permutation here into a permutation + + align:start position:0% +permutation here into a permutation + + + align:start position:0% +permutation here into a permutation +there why because if you have an even + + align:start position:0% +there why because if you have an even + + + align:start position:0% +there why because if you have an even +permutation here any element here has an + + align:start position:0% +permutation here any element here has an + + + align:start position:0% +permutation here any element here has an +even number of transmutations of + + align:start position:0% +even number of transmutations of + + + align:start position:0% +even number of transmutations of +transpositions so this is another + + align:start position:0% +transpositions so this is another + + + align:start position:0% +transpositions so this is another +transposition it transposes 2 and 1 so + + align:start position:0% +transposition it transposes 2 and 1 so + + + align:start position:0% +transposition it transposes 2 and 1 so +when you multiply an element here by p21 + + align:start position:0% +when you multiply an element here by p21 + + + align:start position:0% +when you multiply an element here by p21 +if it has an even number of + + align:start position:0% +if it has an even number of + + + align:start position:0% +if it has an even number of +transpositions now it has an odd one so + + align:start position:0% +transpositions now it has an odd one so + + + align:start position:0% +transpositions now it has an odd one so +it must land somewhere here so any this + + align:start position:0% +it must land somewhere here so any this + + + align:start position:0% +it must land somewhere here so any this +ptoo 1 maps the even the even + + align:start position:0% +ptoo 1 maps the even the even + + + align:start position:0% +ptoo 1 maps the even the even +permutations to the odd permutations + + align:start position:0% + + + + align:start position:0% + +moreover it maps them well in what's + + align:start position:0% +moreover it maps them well in what's + + + align:start position:0% +moreover it maps them well in what's +called one-to-one fashion if you have + + align:start position:0% +called one-to-one fashion if you have + + + align:start position:0% +called one-to-one fashion if you have +two permutations here that are different + + align:start position:0% +two permutations here that are different + + + align:start position:0% +two permutations here that are different +it will map to two permutations here + + align:start position:0% +it will map to two permutations here + + + align:start position:0% +it will map to two permutations here +that are different + + align:start position:0% +that are different + + + align:start position:0% +that are different +why because suppose you have here P I + + align:start position:0% +why because suppose you have here P I + + + align:start position:0% +why because suppose you have here P I +and PJ two permutations one is mapped to + + align:start position:0% +and PJ two permutations one is mapped to + + + align:start position:0% +and PJ two permutations one is mapped to +p2 one P I and the other is mapped to p2 + + align:start position:0% +p2 one P I and the other is mapped to p2 + + + align:start position:0% +p2 one P I and the other is mapped to p2 +one PJ but if P I and PJ are different + + align:start position:0% +one PJ but if P I and PJ are different + + + align:start position:0% +one PJ but if P I and PJ are different +to permutations here i and j p i and pj + + align:start position:0% +to permutations here i and j p i and pj + + + align:start position:0% +to permutations here i and j p i and pj +and if they are different then it + + align:start position:0% +and if they are different then it + + + align:start position:0% +and if they are different then it +follows that these two are different as + + align:start position:0% +follows that these two are different as + + + align:start position:0% +follows that these two are different as +well after you multiply them by p21 why + + align:start position:0% +well after you multiply them by p21 why + + + align:start position:0% +well after you multiply them by p21 why +because if they were equal p21 has an + + align:start position:0% +because if they were equal p21 has an + + + align:start position:0% +because if they were equal p21 has an +inverse is itself p21 so you could + + align:start position:0% +inverse is itself p21 so you could + + + align:start position:0% +inverse is itself p21 so you could +multiply them in and then you would show + + align:start position:0% +multiply them in and then you would show + + + align:start position:0% +multiply them in and then you would show +that p is equal to pj and that can't + + align:start position:0% +that p is equal to pj and that can't + + + align:start position:0% +that p is equal to pj and that can't +happen so two different elements here + + align:start position:0% +happen so two different elements here + + + align:start position:0% +happen so two different elements here +will go to two different elements there + + align:start position:0% +will go to two different elements there + + + align:start position:0% +will go to two different elements there +so if you think of your all your + + align:start position:0% +so if you think of your all your + + + align:start position:0% +so if you think of your all your +elements here go if you have 20 elements + + align:start position:0% +elements here go if you have 20 elements + + + align:start position:0% +elements here go if you have 20 elements +here they go to 20 elements here the + + align:start position:0% +here they go to 20 elements here the + + + align:start position:0% +here they go to 20 elements here the +only thing that can happen is that some + + align:start position:0% +only thing that can happen is that some + + + align:start position:0% +only thing that can happen is that some +elements are not reached here that would + + align:start position:0% +elements are not reached here that would + + + align:start position:0% +elements are not reached here that would +mean that these two sets are not the + + align:start position:0% +mean that these two sets are not the + + + align:start position:0% +mean that these two sets are not the +same so you need to show that this map + + align:start position:0% +same so you need to show that this map + + + align:start position:0% +same so you need to show that this map +reaches everybody so this shows it's a + + align:start position:0% +reaches everybody so this shows it's a + + + align:start position:0% +reaches everybody so this shows it's a +one to one to one map and in fact it's + + align:start position:0% +one to one to one map and in fact it's + + + align:start position:0% +one to one to one map and in fact it's +kind of a joke but in a way to think of + + align:start position:0% +kind of a joke but in a way to think of + + + align:start position:0% +kind of a joke but in a way to think of +this one to one really means to to two + + align:start position:0% +this one to one really means to to two + + + align:start position:0% +this one to one really means to to two +in the sense that two things go to two + + align:start position:0% +in the sense that two things go to two + + + align:start position:0% +in the sense that two things go to two +things so it's kind of a funny name + + align:start position:0% +things so it's kind of a funny name + + + align:start position:0% +things so it's kind of a funny name +one to one so the other thing is that + + align:start position:0% +one to one so the other thing is that + + + align:start position:0% +one to one so the other thing is that +you need to show that everybody reaches + + align:start position:0% +you need to show that everybody reaches + + + align:start position:0% +you need to show that everybody reaches +so the map is + + align:start position:0% +so the map is + + + align:start position:0% +so the map is +cause surjective everybody reaches so + + align:start position:0% +cause surjective everybody reaches so + + + align:start position:0% +cause surjective everybody reaches so +it's clear that everybody reaches + + align:start position:0% +it's clear that everybody reaches + + + align:start position:0% +it's clear that everybody reaches +because if you have a P K in here + + align:start position:0% +because if you have a P K in here + + + align:start position:0% +because if you have a P K in here +permutation P K this P K can be written + + align:start position:0% +permutation P K this P K can be written + + + align:start position:0% +permutation P K this P K can be written +as P - 1 times P - 1 x PK plus P - 1 + + align:start position:0% +as P - 1 times P - 1 x PK plus P - 1 + + + align:start position:0% +as P - 1 times P - 1 x PK plus P - 1 +times P - 1 is 1 and this B K since this + + align:start position:0% +times P - 1 is 1 and this B K since this + + + align:start position:0% +times P - 1 is 1 and this B K since this +was an odd permutation this is an even 1 + + align:start position:0% +was an odd permutation this is an even 1 + + + align:start position:0% +was an odd permutation this is an even 1 +and then you've shown that PK is + + align:start position:0% +and then you've shown that PK is + + + align:start position:0% +and then you've shown that PK is +obtained by acting with P - 1 on some + + align:start position:0% +obtained by acting with P - 1 on some + + + align:start position:0% +obtained by acting with P - 1 on some +even permutation so you reach so the map + + align:start position:0% +even permutation so you reach so the map + + + align:start position:0% +even permutation so you reach so the map +is surjective directive and therefore + + align:start position:0% +is surjective directive and therefore + + + align:start position:0% +is surjective directive and therefore +these two things are the same they're + + align:start position:0% +these two things are the same they're + + + align:start position:0% +these two things are the same they're +identical numbers of even and odd + + align:start position:0% +identical numbers of even and odd + + + align:start position:0% +identical numbers of even and odd +permutations a very nice fact about + + align:start position:0% +permutations a very nice fact about + + + align:start position:0% +permutations a very nice fact about +these groups \ No newline at end of file diff --git a/YiqIkSHSmyc.txt b/YiqIkSHSmyc.txt new file mode 100644 index 0000000000000000000000000000000000000000..caa13ac6cd1b5ee06538d54bc9ca9b7db6486055 --- /dev/null +++ b/YiqIkSHSmyc.txt @@ -0,0 +1,6794 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT OpenCourseWare continue to + + align:start position:0% +will help MIT OpenCourseWare continue to + + + align:start position:0% +will help MIT OpenCourseWare continue to +offer high quality educational resources + + align:start position:0% +offer high quality educational resources + + + align:start position:0% +offer high quality educational resources +for free + + align:start position:0% +for free + + + align:start position:0% +for free +to make a donation or to view additional + + align:start position:0% +to make a donation or to view additional + + + align:start position:0% +to make a donation or to view additional +materials from hundreds of MIT courses + + align:start position:0% +materials from hundreds of MIT courses + + + align:start position:0% +materials from hundreds of MIT courses +visit MIT opencourseware at ocw.mit.edu + + align:start position:0% + + + + align:start position:0% + +shall we start let me just say this is a + + align:start position:0% +shall we start let me just say this is a + + + align:start position:0% +shall we start let me just say this is a +great adventure for me to be here all on + + align:start position:0% +great adventure for me to be here all on + + + align:start position:0% +great adventure for me to be here all on +my own teaching a course that involves + + align:start position:0% +my own teaching a course that involves + + + align:start position:0% +my own teaching a course that involves +learning from data so it's exciting + + align:start position:0% +learning from data so it's exciting + + + align:start position:0% +learning from data so it's exciting +subject and a lot of linear algebra goes + + align:start position:0% +subject and a lot of linear algebra goes + + + align:start position:0% +subject and a lot of linear algebra goes +into it so it's sort of a second course + + align:start position:0% +into it so it's sort of a second course + + + align:start position:0% +into it so it's sort of a second course +in linear algebra can I just + + align:start position:0% +in linear algebra can I just + + + align:start position:0% +in linear algebra can I just +you'll know what so there is a stellar + + align:start position:0% +you'll know what so there is a stellar + + + align:start position:0% +you'll know what so there is a stellar +site established and that will be the + + align:start position:0% +site established and that will be the + + + align:start position:0% +site established and that will be the +basic thing that we use this is a public + + align:start position:0% +basic thing that we use this is a public + + + align:start position:0% +basic thing that we use this is a public +site method mit.edu + + align:start position:0% +site method mit.edu + + + align:start position:0% +site method mit.edu +learning from data and so a book is + + align:start position:0% +learning from data and so a book is + + + align:start position:0% +learning from data and so a book is +coming pretty quickly as we speak or + + align:start position:0% +coming pretty quickly as we speak or + + + align:start position:0% +coming pretty quickly as we speak or +after we speak and that site has the + + align:start position:0% +after we speak and that site has the + + + align:start position:0% +after we speak and that site has the +table of contents of the book which + + align:start position:0% +table of contents of the book which + + + align:start position:0% +table of contents of the book which +would give you an idea of what could be + + align:start position:0% +would give you an idea of what could be + + + align:start position:0% +would give you an idea of what could be +in the course and I and I printed out a + + align:start position:0% +in the course and I and I printed out a + + + align:start position:0% +in the course and I and I printed out a +copy for everybody just of that one page + + align:start position:0% +copy for everybody just of that one page + + + align:start position:0% +copy for everybody just of that one page +that's probably the final first and last + + align:start position:0% +that's probably the final first and last + + + align:start position:0% +that's probably the final first and last +handout maybe with with the table of + + align:start position:0% +handout maybe with with the table of + + + align:start position:0% +handout maybe with with the table of +contents which you'll see there and also + + align:start position:0% +contents which you'll see there and also + + + align:start position:0% +contents which you'll see there and also +you'll see there the first two sections + + align:start position:0% +you'll see there the first two sections + + + align:start position:0% +you'll see there the first two sections +of the book which is what I'll talk + + align:start position:0% +of the book which is what I'll talk + + + align:start position:0% +of the book which is what I'll talk +about today and and on a little bit in + + align:start position:0% +about today and and on a little bit in + + + align:start position:0% +about today and and on a little bit in +to Friday so that's that's linear + + align:start position:0% +to Friday so that's that's linear + + + align:start position:0% +to Friday so that's that's linear +algebra of course because the course + + align:start position:0% +algebra of course because the course + + + align:start position:0% +algebra of course because the course +sort of begins with linear algebra + + align:start position:0% +sort of begins with linear algebra + + + align:start position:0% +sort of begins with linear algebra +actually things that you would know from + + align:start position:0% +actually things that you would know from + + + align:start position:0% +actually things that you would know from +1806 but you but this is a way to say + + align:start position:0% +1806 but you but this is a way to say + + + align:start position:0% +1806 but you but this is a way to say +this is really important stuff so that's + + align:start position:0% +this is really important stuff so that's + + + align:start position:0% +this is really important stuff so that's +what I'll do today I'd like to do some + + align:start position:0% +what I'll do today I'd like to do some + + + align:start position:0% +what I'll do today I'd like to do some +start on the linear algebra today + + align:start position:0% +start on the linear algebra today + + + align:start position:0% +start on the linear algebra today +and here's the great facts about the + + align:start position:0% +and here's the great facts about the + + + align:start position:0% +and here's the great facts about the +course at least we knew there were so we + + align:start position:0% +course at least we knew there were so we + + + align:start position:0% +course at least we knew there were so we +taught it last year several of us + + align:start position:0% +taught it last year several of us + + + align:start position:0% +taught it last year several of us +together and we knew there wouldn't be a + + align:start position:0% +together and we knew there wouldn't be a + + + align:start position:0% +together and we knew there wouldn't be a +final exam but we imagined there might + + align:start position:0% +final exam but we imagined there might + + + align:start position:0% +final exam but we imagined there might +be quizzes along the way but then we + + align:start position:0% +be quizzes along the way but then we + + + align:start position:0% +be quizzes along the way but then we +couldn't think of anything to put on the + + align:start position:0% +couldn't think of anything to put on the + + + align:start position:0% +couldn't think of anything to put on the +quizzes so we canceled those but you do + + align:start position:0% +quizzes so we canceled those but you do + + + align:start position:0% +quizzes so we canceled those but you do +learn a lot nevertheless and so I guess + + align:start position:0% +learn a lot nevertheless and so I guess + + + align:start position:0% +learn a lot nevertheless and so I guess +we base the grades on the homeworks so + + align:start position:0% +we base the grades on the homeworks so + + + align:start position:0% +we base the grades on the homeworks so +the homeworks will be partly linear + + align:start position:0% +the homeworks will be partly linear + + + align:start position:0% +the homeworks will be partly linear +algebra questions and partly online you + + align:start position:0% +algebra questions and partly online you + + + align:start position:0% +algebra questions and partly online you +know like recognizing handwriting + + align:start position:0% +know like recognizing handwriting + + + align:start position:0% +know like recognizing handwriting +stitching images together many other + + align:start position:0% +stitching images together many other + + + align:start position:0% +stitching images together many other +things and I'll talk about those as we + + align:start position:0% +things and I'll talk about those as we + + + align:start position:0% +things and I'll talk about those as we +go right good yeah + + align:start position:0% +go right good yeah + + + align:start position:0% +go right good yeah +so this that's the general picture and + + align:start position:0% +so this that's the general picture and + + + align:start position:0% +so this that's the general picture and +I'll say more about it today and I could + + align:start position:0% +I'll say more about it today and I could + + + align:start position:0% +I'll say more about it today and I could +answer any question about it so we're + + align:start position:0% +answer any question about it so we're + + + align:start position:0% +answer any question about it so we're +getting videotaped so if anybody's + + align:start position:0% +getting videotaped so if anybody's + + + align:start position:0% +getting videotaped so if anybody's +bashful sit at the far back but it'll be + + align:start position:0% +bashful sit at the far back but it'll be + + + align:start position:0% +bashful sit at the far back but it'll be +fun yeah you may know the videos for + + align:start position:0% +fun yeah you may know the videos for + + + align:start position:0% +fun yeah you may know the videos for +1806 so this is like the next step 1806 + + align:start position:0% +1806 so this is like the next step 1806 + + + align:start position:0% +1806 so this is like the next step 1806 +five that's pretty exciting for me so + + align:start position:0% +five that's pretty exciting for me so + + + align:start position:0% +five that's pretty exciting for me so +any question or shall I do a little math + + align:start position:0% +any question or shall I do a little math + + + align:start position:0% +any question or shall I do a little math +why not and then and then I'll say a + + align:start position:0% +why not and then and then I'll say a + + + align:start position:0% +why not and then and then I'll say a +little more about the course just so you + + align:start position:0% +little more about the course just so you + + + align:start position:0% +little more about the course just so you +have an idea of what what's ahead yeah + + align:start position:0% +have an idea of what what's ahead yeah + + + align:start position:0% +have an idea of what what's ahead yeah +and it looks like this room is exactly + + align:start position:0% +and it looks like this room is exactly + + + align:start position:0% +and it looks like this room is exactly +the right size to me so I'm pleased okay + + align:start position:0% +the right size to me so I'm pleased okay + + + align:start position:0% +the right size to me so I'm pleased okay +so so what's the deal in linear algebra + + align:start position:0% +so so what's the deal in linear algebra + + + align:start position:0% +so so what's the deal in linear algebra +let me I'll start forgive me if I start + + align:start position:0% +let me I'll start forgive me if I start + + + align:start position:0% +let me I'll start forgive me if I start +with what I do the very first day in + + align:start position:0% +with what I do the very first day in + + + align:start position:0% +with what I do the very first day in +1806 which is multiply a matrix by a + + align:start position:0% +1806 which is multiply a matrix by a + + + align:start position:0% +1806 which is multiply a matrix by a +vector and then I'll graduate to + + align:start position:0% +vector and then I'll graduate to + + + align:start position:0% +vector and then I'll graduate to +multiplying a matrix by a May + + align:start position:0% +multiplying a matrix by a May + + + align:start position:0% +multiplying a matrix by a May +tricks so that and you will say I know + + align:start position:0% +tricks so that and you will say I know + + + align:start position:0% +tricks so that and you will say I know +that stuff but do you know it the right + + align:start position:0% +that stuff but do you know it the right + + + align:start position:0% +that stuff but do you know it the right +way do you think of the multiplication + + align:start position:0% +way do you think of the multiplication + + + align:start position:0% +way do you think of the multiplication +the right way so let me tell you what I + + align:start position:0% +the right way so let me tell you what I + + + align:start position:0% +the right way so let me tell you what I +believe to be the right way so let me + + align:start position:0% +believe to be the right way so let me + + + align:start position:0% +believe to be the right way so let me +take a matrix say two three five one one + + align:start position:0% +take a matrix say two three five one one + + + align:start position:0% +take a matrix say two three five one one +seven and three four twelve okay and + + align:start position:0% +seven and three four twelve okay and + + + align:start position:0% +seven and three four twelve okay and +I'll always call matrices a okay so + + align:start position:0% +I'll always call matrices a okay so + + + align:start position:0% +I'll always call matrices a okay so +first step is just a times X a times a + + align:start position:0% +first step is just a times X a times a + + + align:start position:0% +first step is just a times X a times a +vector so I multiply a a by let's say x1 + + align:start position:0% +vector so I multiply a a by let's say x1 + + + align:start position:0% +vector so I multiply a a by let's say x1 +x2 x3 and how do I look at that answer + + align:start position:0% +x2 x3 and how do I look at that answer + + + align:start position:0% +x2 x3 and how do I look at that answer +so the choice is think of the rows of + + align:start position:0% +so the choice is think of the rows of + + + align:start position:0% +so the choice is think of the rows of +the matrix or think of the columns and + + align:start position:0% +the matrix or think of the columns and + + + align:start position:0% +the matrix or think of the columns and +if you think of the rows which is the + + align:start position:0% +if you think of the rows which is the + + + align:start position:0% +if you think of the rows which is the +standard way to multiply you would take + + align:start position:0% +standard way to multiply you would take + + + align:start position:0% +standard way to multiply you would take +the dot product so the first way is the + + align:start position:0% +the dot product so the first way is the + + + align:start position:0% +the dot product so the first way is the +first way is dot product of Row Row + + align:start position:0% +first way is dot product of Row Row + + + align:start position:0% +first way is dot product of Row Row +dotted with X right 2 X 1 plus X 2 plus + + align:start position:0% +dotted with X right 2 X 1 plus X 2 plus + + + align:start position:0% +dotted with X right 2 X 1 plus X 2 plus +3 X 3 it gives you the answer a + + align:start position:0% +3 X 3 it gives you the answer a + + + align:start position:0% +3 X 3 it gives you the answer a +component at a time that's the low level + + align:start position:0% +component at a time that's the low level + + + align:start position:0% +component at a time that's the low level +way the good way to see it is vector + + align:start position:0% +way the good way to see it is vector + + + align:start position:0% +way the good way to see it is vector +wise see this as X 1 multiplies that + + align:start position:0% +wise see this as X 1 multiplies that + + + align:start position:0% +wise see this as X 1 multiplies that +first column X 2 times the second column + + align:start position:0% +first column X 2 times the second column + + + align:start position:0% +first column X 2 times the second column +1 1 7 and X 3 times the third column 3 4 + + align:start position:0% +1 1 7 and X 3 times the third column 3 4 + + + align:start position:0% +1 1 7 and X 3 times the third column 3 4 + + align:start position:0% + + + + align:start position:0% + +good so it's a combination of vectors + + align:start position:0% +good so it's a combination of vectors + + + align:start position:0% +good so it's a combination of vectors +and of course it produces a vector and + + align:start position:0% +and of course it produces a vector and + + + align:start position:0% +and of course it produces a vector and +here we have a three by three matrix and + + align:start position:0% +here we have a three by three matrix and + + + align:start position:0% +here we have a three by three matrix and +our vectors are in r3 and most vectors + + align:start position:0% +our vectors are in r3 and most vectors + + + align:start position:0% +our vectors are in r3 and most vectors +will be in r3 or RN for this course so + + align:start position:0% +will be in r3 or RN for this course so + + + align:start position:0% +will be in r3 or RN for this course so +that's the right answer and of course + + align:start position:0% +that's the right answer and of course + + + align:start position:0% +that's the right answer and of course +the first component is 2 X 1 + 1 X 2 + 3 + + align:start position:0% +the first component is 2 X 1 + 1 X 2 + 3 + + + align:start position:0% +the first component is 2 X 1 + 1 X 2 + 3 +X 3 the same 2 1 3 the same dot product + + align:start position:0% +X 3 the same 2 1 3 the same dot product + + + align:start position:0% +X 3 the same 2 1 3 the same dot product +comes out right but you see it like sort + + align:start position:0% +comes out right but you see it like sort + + + align:start position:0% +comes out right but you see it like sort +of all at once instead of piecemeal so + + align:start position:0% +of all at once instead of piecemeal so + + + align:start position:0% +of all at once instead of piecemeal so +that's you know part of the course I + + align:start position:0% +that's you know part of the course I + + + align:start position:0% +that's you know part of the course I +guess part of what I hope to get across + + align:start position:0% +guess part of what I hope to get across + + + align:start position:0% +guess part of what I hope to get across +is thinking of a matrix of a matrix as a + + align:start position:0% +is thinking of a matrix of a matrix as a + + + align:start position:0% +is thinking of a matrix of a matrix as a +whole thing not just a bunch of 9 or or + + align:start position:0% +whole thing not just a bunch of 9 or or + + + align:start position:0% +whole thing not just a bunch of 9 or or +M times n numbers but thinking of it as + + align:start position:0% +M times n numbers but thinking of it as + + + align:start position:0% +M times n numbers but thinking of it as +a as a thing a matrix multiplies a + + align:start position:0% +a as a thing a matrix multiplies a + + + align:start position:0% +a as a thing a matrix multiplies a +vector to give another vector yeah think + + align:start position:0% +vector to give another vector yeah think + + + align:start position:0% +vector to give another vector yeah think +so that when I say ax that you + + align:start position:0% +so that when I say ax that you + + + align:start position:0% +so that when I say ax that you +immediately think that you immediately + + align:start position:0% +immediately think that you immediately + + + align:start position:0% +immediately think that you immediately +think okay ax has a clear meaning it's a + + align:start position:0% +think okay ax has a clear meaning it's a + + + align:start position:0% +think okay ax has a clear meaning it's a +combination of the columns of a so now + + align:start position:0% +combination of the columns of a so now + + + align:start position:0% +combination of the columns of a so now +let me take that next step and the next + + align:start position:0% +let me take that next step and the next + + + align:start position:0% +let me take that next step and the next +step is think about all combinations of + + align:start position:0% +step is think about all combinations of + + + align:start position:0% +step is think about all combinations of +the columns of a we take the matrix a + + align:start position:0% +the columns of a we take the matrix a + + + align:start position:0% +the columns of a we take the matrix a +and we take all X's and we imagine all + + align:start position:0% +and we take all X's and we imagine all + + + align:start position:0% +and we take all X's and we imagine all +the outputs and what I want to ask you + + align:start position:0% +the outputs and what I want to ask you + + + align:start position:0% +the outputs and what I want to ask you +is what does that look like if I just + + align:start position:0% +is what does that look like if I just + + + align:start position:0% +is what does that look like if I just +take 1 X 1 vector X I get a vector + + align:start position:0% +take 1 X 1 vector X I get a vector + + + align:start position:0% +take 1 X 1 vector X I get a vector +output takes a vector to a vector but + + align:start position:0% +output takes a vector to a vector but + + + align:start position:0% +output takes a vector to a vector but +now I take all X's the hole all of + + align:start position:0% +now I take all X's the hole all of + + + align:start position:0% +now I take all X's the hole all of +vectors X in or in 3d and I get all + + align:start position:0% +vectors X in or in 3d and I get all + + + align:start position:0% +vectors X in or in 3d and I get all +these answers and I think of them all + + align:start position:0% +these answers and I think of them all + + + align:start position:0% +these answers and I think of them all +together and so I've got a bunch of + + align:start position:0% +together and so I've got a bunch of + + + align:start position:0% +together and so I've got a bunch of +vectors infinitely many vectors actually + + align:start position:0% +vectors infinitely many vectors actually + + + align:start position:0% +vectors infinitely many vectors actually +and the question is what if I plot those + + align:start position:0% +and the question is what if I plot those + + + align:start position:0% +and the question is what if I plot those +infinitely many vectors what do I have + + align:start position:0% +infinitely many vectors what do I have + + + align:start position:0% +infinitely many vectors what do I have +and the beauty of linear algebra is that + + align:start position:0% +and the beauty of linear algebra is that + + + align:start position:0% +and the beauty of linear algebra is that +questions like this + + align:start position:0% +questions like this + + + align:start position:0% +questions like this +you can answer them and they you + + align:start position:0% +you can answer them and they you + + + align:start position:0% +you can answer them and they you +intuitively see it you certainly see it + + align:start position:0% +intuitively see it you certainly see it + + + align:start position:0% +intuitively see it you certainly see it +in 3d and you kind of have the right and + + align:start position:0% +in 3d and you kind of have the right and + + + align:start position:0% +in 3d and you kind of have the right and +the right idea in ten dimensions even + + align:start position:0% +the right idea in ten dimensions even + + + align:start position:0% +the right idea in ten dimensions even +though most of us don't see too well in + + align:start position:0% +though most of us don't see too well in + + + align:start position:0% +though most of us don't see too well in +10 D in our 10 but here we got three + + align:start position:0% +10 D in our 10 but here we got three + + + align:start position:0% +10 D in our 10 but here we got three +okay so so do you see what I'm saying + + align:start position:0% +okay so so do you see what I'm saying + + + align:start position:0% +okay so so do you see what I'm saying +I'm taking all X's so now so all a X + + align:start position:0% + + + + align:start position:0% + +gives us a big bunch of vectors and that + + align:start position:0% +gives us a big bunch of vectors and that + + + align:start position:0% +gives us a big bunch of vectors and that +collection of vectors is called the + + align:start position:0% +collection of vectors is called the + + + align:start position:0% +collection of vectors is called the +column space of a it's a space in other + + align:start position:0% +column space of a it's a space in other + + + align:start position:0% +column space of a it's a space in other +words that that's the keyword there the + + align:start position:0% +words that that's the keyword there the + + + align:start position:0% +words that that's the keyword there the +column space of a and I'll just write it + + align:start position:0% +column space of a and I'll just write it + + + align:start position:0% +column space of a and I'll just write it +as C of a when I need a letters for it + + align:start position:0% +as C of a when I need a letters for it + + + align:start position:0% +as C of a when I need a letters for it +okay so I'm going to ask you what does + + align:start position:0% +okay so I'm going to ask you what does + + + align:start position:0% +okay so I'm going to ask you what does +this column space look like and that + + align:start position:0% +this column space look like and that + + + align:start position:0% +this column space look like and that +depends on the matrix sometimes the + + align:start position:0% +depends on the matrix sometimes the + + + align:start position:0% +depends on the matrix sometimes the +column space would be the whole of r3 + + align:start position:0% +column space would be the whole of r3 + + + align:start position:0% +column space would be the whole of r3 +sometimes it's a smaller set in r3 or + + align:start position:0% +sometimes it's a smaller set in r3 or + + + align:start position:0% +sometimes it's a smaller set in r3 or +space + + align:start position:0% +space + + + align:start position:0% +space +do you know what it is in this case do I + + align:start position:0% +do you know what it is in this case do I + + + align:start position:0% +do you know what it is in this case do I +get do I get all of 3d out of these guys + + align:start position:0% +get do I get all of 3d out of these guys + + + align:start position:0% +get do I get all of 3d out of these guys +by choosing all X 1 and X 2 and X 3 it + + align:start position:0% +by choosing all X 1 and X 2 and X 3 it + + + align:start position:0% +by choosing all X 1 and X 2 and X 3 it +seemed like if it was a random matrix + + align:start position:0% +seemed like if it was a random matrix + + + align:start position:0% +seemed like if it was a random matrix +the answer would be surely yes if the + + align:start position:0% +the answer would be surely yes if the + + + align:start position:0% +the answer would be surely yes if the +random 3x3 matrix is its column space is + + align:start position:0% +random 3x3 matrix is its column space is + + + align:start position:0% +random 3x3 matrix is its column space is +going to be all of our three its columns + + align:start position:0% +going to be all of our three its columns + + + align:start position:0% +going to be all of our three its columns +are going to be independent its rows are + + align:start position:0% +are going to be independent its rows are + + + align:start position:0% +are going to be independent its rows are +going to be independent it's going to be + + align:start position:0% +going to be independent it's going to be + + + align:start position:0% +going to be independent it's going to be +invertible it's going to be great but is + + align:start position:0% +invertible it's going to be great but is + + + align:start position:0% +invertible it's going to be great but is +this matrix what's up with that matrix + + align:start position:0% +this matrix what's up with that matrix + + + align:start position:0% +this matrix what's up with that matrix +no it's not right + + align:start position:0% +no it's not right + + + align:start position:0% +no it's not right +so what do I get instead of all of our + + align:start position:0% +so what do I get instead of all of our + + + align:start position:0% +so what do I get instead of all of our +three I get a plane yeah if you get that + + align:start position:0% +three I get a plane yeah if you get that + + + align:start position:0% +three I get a plane yeah if you get that +in sight so by taking all X's + + align:start position:0% +in sight so by taking all X's + + + align:start position:0% +in sight so by taking all X's +everybody's with me all X's here so so + + align:start position:0% +everybody's with me all X's here so so + + + align:start position:0% +everybody's with me all X's here so so +that means that like it fills in + + align:start position:0% +that means that like it fills in + + + align:start position:0% +that means that like it fills in +whatever and well because it's linear + + align:start position:0% +whatever and well because it's linear + + + align:start position:0% +whatever and well because it's linear +algebra it's gonna be likely all of our + + align:start position:0% +algebra it's gonna be likely all of our + + + align:start position:0% +algebra it's gonna be likely all of our +three + + align:start position:0% +three + + + align:start position:0% +three +or a plane or even a line what let me + + align:start position:0% +or a plane or even a line what let me + + + align:start position:0% +or a plane or even a line what let me +just bat over here for a moment + + align:start position:0% +just bat over here for a moment + + + align:start position:0% +just bat over here for a moment +give me a matrix which would whose + + align:start position:0% +give me a matrix which would whose + + + align:start position:0% +give me a matrix which would whose +column space would only be a line all + + align:start position:0% +column space would only be a line all + + + align:start position:0% +column space would only be a line all +one's okay wow that's a let me liven it + + align:start position:0% +one's okay wow that's a let me liven it + + + align:start position:0% +one's okay wow that's a let me liven it +up a little three three three eight + + align:start position:0% +up a little three three three eight + + + align:start position:0% +up a little three three three eight +eight eight I think okay so I think that + + align:start position:0% +eight eight I think okay so I think that + + + align:start position:0% +eight eight I think okay so I think that +the combinations of those columns are + + align:start position:0% +the combinations of those columns are + + + align:start position:0% +the combinations of those columns are +all on the same line look that says that + + align:start position:0% +all on the same line look that says that + + + align:start position:0% +all on the same line look that says that +the column space is just a line and I + + align:start position:0% +the column space is just a line and I + + + align:start position:0% +the column space is just a line and I +would say then that the matrix so a + + align:start position:0% +would say then that the matrix so a + + + align:start position:0% +would say then that the matrix so a +column space of this a is a line another + + align:start position:0% +column space of this a is a line another + + + align:start position:0% +column space of this a is a line another +way I could say this is that the rank of + + align:start position:0% +way I could say this is that the rank of + + + align:start position:0% +way I could say this is that the rank of +the matrix is one the rank is sort of + + align:start position:0% +the matrix is one the rank is sort of + + + align:start position:0% +the matrix is one the rank is sort of +the dimension of the column space well + + align:start position:0% +the dimension of the column space well + + + align:start position:0% +the dimension of the column space well +not sort of that's what it is the rank + + align:start position:0% +not sort of that's what it is the rank + + + align:start position:0% +not sort of that's what it is the rank +is the dimension of the column see + + align:start position:0% +is the dimension of the column see + + + align:start position:0% +is the dimension of the column see +everybody sees that you get a line + + align:start position:0% +everybody sees that you get a line + + + align:start position:0% +everybody sees that you get a line +because any combination x1 of that plus + + align:start position:0% +because any combination x1 of that plus + + + align:start position:0% +because any combination x1 of that plus +x2 of that plus x3 of that is is going + + align:start position:0% +x2 of that plus x3 of that is is going + + + align:start position:0% +x2 of that plus x3 of that is is going +to go in in along that line here's the + + align:start position:0% +to go in in along that line here's the + + + align:start position:0% +to go in in along that line here's the +first column here's the second column + + align:start position:0% +first column here's the second column + + + align:start position:0% +first column here's the second column +they're all on a line so I'll never get + + align:start position:0% +they're all on a line so I'll never get + + + align:start position:0% +they're all on a line so I'll never get +off that line if I allow all X's I'll + + align:start position:0% +off that line if I allow all X's I'll + + + align:start position:0% +off that line if I allow all X's I'll +get the whole line + + align:start position:0% +get the whole line + + + align:start position:0% +get the whole line +now here you said not a line right what + + align:start position:0% +now here you said not a line right what + + + align:start position:0% +now here you said not a line right what +was what was the column space for this + + align:start position:0% +was what was the column space for this + + + align:start position:0% +was what was the column space for this +guy plain now why isn't it all of our + + align:start position:0% +guy plain now why isn't it all of our + + + align:start position:0% +guy plain now why isn't it all of our +three what what is what do you see that + + align:start position:0% +three what what is what do you see that + + + align:start position:0% +three what what is what do you see that +special there because it is special + + align:start position:0% +special there because it is special + + + align:start position:0% +special there because it is special +that's making the column space sort of + + align:start position:0% +that's making the column space sort of + + + align:start position:0% +that's making the column space sort of +special a plane instead of the whole + + align:start position:0% +special a plane instead of the whole + + + align:start position:0% +special a plane instead of the whole +thing yeah what's up with these three + + align:start position:0% +thing yeah what's up with these three + + + align:start position:0% +thing yeah what's up with these three +columns the third column is the sum of + + align:start position:0% +columns the third column is the sum of + + + align:start position:0% +columns the third column is the sum of +these two so the first column is fine to + + align:start position:0% +these two so the first column is fine to + + + align:start position:0% +these two so the first column is fine to +3/5 second column is in a different + + align:start position:0% +3/5 second column is in a different + + + align:start position:0% +3/5 second column is in a different +direction and when I take combinations + + align:start position:0% +direction and when I take combinations + + + align:start position:0% +direction and when I take combinations +of the first two columns what will I get + + align:start position:0% +of the first two columns what will I get + + + align:start position:0% +of the first two columns what will I get +sorry to keep asking your questions but + + align:start position:0% +sorry to keep asking your questions but + + + align:start position:0% +sorry to keep asking your questions but +that's that's + + align:start position:0% + + + + align:start position:0% + +anyway that's what I always do so so so + + align:start position:0% +anyway that's what I always do so so so + + + align:start position:0% +anyway that's what I always do so so so +the fur the combinations of those first + + align:start position:0% +the fur the combinations of those first + + + align:start position:0% +the fur the combinations of those first +two columns are a plane because they're + + align:start position:0% +two columns are a plane because they're + + + align:start position:0% +two columns are a plane because they're +in different everybody kind of sees that + + align:start position:0% +in different everybody kind of sees that + + + align:start position:0% +in different everybody kind of sees that +picture we've got one column one going + + align:start position:0% +picture we've got one column one going + + + align:start position:0% +picture we've got one column one going +that way and call them to go in that way + + align:start position:0% +that way and call them to go in that way + + + align:start position:0% +that way and call them to go in that way +and then if I take any multiple of + + align:start position:0% +and then if I take any multiple of + + + align:start position:0% +and then if I take any multiple of +column one I've got a whole line any + + align:start position:0% +column one I've got a whole line any + + + align:start position:0% +column one I've got a whole line any +multiple of column two and then when I + + align:start position:0% +multiple of column two and then when I + + + align:start position:0% +multiple of column two and then when I +put the two together it fills in the + + align:start position:0% +put the two together it fills in the + + + align:start position:0% +put the two together it fills in the +fills in the plane yeah yeah our ear + + align:start position:0% +fills in the plane yeah yeah our ear + + + align:start position:0% +fills in the plane yeah yeah our ear +intuition says that's right so this is a + + align:start position:0% +intuition says that's right so this is a + + + align:start position:0% +intuition says that's right so this is a +matrix of rank what's the rank of this + + align:start position:0% +matrix of rank what's the rank of this + + + align:start position:0% +matrix of rank what's the rank of this +matrix two because it's got two + + align:start position:0% +matrix two because it's got two + + + align:start position:0% +matrix two because it's got two +independent columns but the third column + + align:start position:0% +independent columns but the third column + + + align:start position:0% +independent columns but the third column +is dependent the third column is a + + align:start position:0% +is dependent the third column is a + + + align:start position:0% +is dependent the third column is a +combination of the others so this is + + align:start position:0% +combination of the others so this is + + + align:start position:0% +combination of the others so this is +matrices like this are really the + + align:start position:0% +matrices like this are really the + + + align:start position:0% +matrices like this are really the +building blocks of linear algebra + + align:start position:0% +building blocks of linear algebra + + + align:start position:0% +building blocks of linear algebra +they're the building blocks of data + + align:start position:0% +they're the building blocks of data + + + align:start position:0% +they're the building blocks of data +science they're rank one matrices and + + align:start position:0% +science they're rank one matrices and + + + align:start position:0% +science they're rank one matrices and +let me show you a special way to think + + align:start position:0% +let me show you a special way to think + + + align:start position:0% +let me show you a special way to think +write those rank one matrices I think of + + align:start position:0% +write those rank one matrices I think of + + + align:start position:0% +write those rank one matrices I think of +this matrix as column vector 1 1 1 times + + align:start position:0% +this matrix as column vector 1 1 1 times + + + align:start position:0% +this matrix as column vector 1 1 1 times +the row vector 1 3 8 so it's a column + + align:start position:0% +the row vector 1 3 8 so it's a column + + + align:start position:0% +the row vector 1 3 8 so it's a column +times a row that's a rank one matrix do + + align:start position:0% +times a row that's a rank one matrix do + + + align:start position:0% +times a row that's a rank one matrix do +you see that it's a that's a true + + align:start position:0% +you see that it's a that's a true + + + align:start position:0% +you see that it's a that's a true +multiplication there it looks a little + + align:start position:0% +multiplication there it looks a little + + + align:start position:0% +multiplication there it looks a little +weird but it's a three by one matrix + + align:start position:0% +weird but it's a three by one matrix + + + align:start position:0% +weird but it's a three by one matrix +times a 1 by 3 matrix these numbers have + + align:start position:0% +times a 1 by 3 matrix these numbers have + + + align:start position:0% +times a 1 by 3 matrix these numbers have +to be the same and then the output is 3 + + align:start position:0% +to be the same and then the output is 3 + + + align:start position:0% +to be the same and then the output is 3 +by 3 and it's that and you see that it + + align:start position:0% +by 3 and it's that and you see that it + + + align:start position:0% +by 3 and it's that and you see that it +factors so I'm going to move on to that + + align:start position:0% +factors so I'm going to move on to that + + + align:start position:0% +factors so I'm going to move on to that +idea the next idea coming up will be + + align:start position:0% +idea the next idea coming up will be + + + align:start position:0% +idea the next idea coming up will be +that that we we can see well that's + + align:start position:0% +that that we we can see well that's + + + align:start position:0% +that that we we can see well that's +coming that we're going to see matrices + + align:start position:0% +coming that we're going to see matrices + + + align:start position:0% +coming that we're going to see matrices +in with two factors okay let me let me + + align:start position:0% +in with two factors okay let me let me + + + align:start position:0% +in with two factors okay let me let me +move to that but but they're back for + + align:start position:0% +move to that but but they're back for + + + align:start position:0% +move to that but but they're back for +this original matrix + + align:start position:0% +this original matrix + + + align:start position:0% +this original matrix +okay so what's with this the column + + align:start position:0% +okay so what's with this the column + + + align:start position:0% +okay so what's with this the column +space is a plane so if I think about now + + align:start position:0% +space is a plane so if I think about now + + + align:start position:0% +space is a plane so if I think about now +the key idea of independent columns how + + align:start position:0% +the key idea of independent columns how + + + align:start position:0% +the key idea of independent columns how +many independent columns have I got here + + align:start position:0% +many independent columns have I got here + + + align:start position:0% +many independent columns have I got here +to correct to the third column if I want + + align:start position:0% +to correct to the third column if I want + + + align:start position:0% +to correct to the third column if I want +to especially pick on that one so I + + align:start position:0% +to especially pick on that one so I + + + align:start position:0% +to especially pick on that one so I +often go left to right so I'll say the + + align:start position:0% +often go left to right so I'll say the + + + align:start position:0% +often go left to right so I'll say the +first guy's good second guy's good the + + align:start position:0% +first guy's good second guy's good the + + + align:start position:0% +first guy's good second guy's good the +third guy not is not independent of the + + align:start position:0% +third guy not is not independent of the + + + align:start position:0% +third guy not is not independent of the +others so I just have two independent + + align:start position:0% +others so I just have two independent + + + align:start position:0% +others so I just have two independent +columns and those are those two columns + + align:start position:0% +columns and those are those two columns + + + align:start position:0% +columns and those are those two columns +would be a basis for the column space so + + align:start position:0% +would be a basis for the column space so + + + align:start position:0% +would be a basis for the column space so +that's the like the critical idea of + + align:start position:0% +that's the like the critical idea of + + + align:start position:0% +that's the like the critical idea of +linear algebra that's what you compute + + align:start position:0% +linear algebra that's what you compute + + + align:start position:0% +linear algebra that's what you compute +with you find a basis and and every + + align:start position:0% +with you find a basis and and every + + + align:start position:0% +with you find a basis and and every +thing in the column space is a + + align:start position:0% +thing in the column space is a + + + align:start position:0% +thing in the column space is a +combination of these including that is + + align:start position:0% +combination of these including that is + + + align:start position:0% +combination of these including that is +also that's already a combination of + + align:start position:0% +also that's already a combination of + + + align:start position:0% +also that's already a combination of +those but everything else in the column + + align:start position:0% +those but everything else in the column + + + align:start position:0% +those but everything else in the column +space is a combination of those two so + + align:start position:0% +space is a combination of those two so + + + align:start position:0% +space is a combination of those two so +so there a basis for it okay so you have + + align:start position:0% +so there a basis for it okay so you have + + + align:start position:0% +so there a basis for it okay so you have +the idea of a times X you have the idea + + align:start position:0% +the idea of a times X you have the idea + + + align:start position:0% +the idea of a times X you have the idea +of column space of a which allows all XS + + align:start position:0% +of column space of a which allows all XS + + + align:start position:0% +of column space of a which allows all XS +then now we're moving into the idea of + + align:start position:0% +then now we're moving into the idea of + + + align:start position:0% +then now we're moving into the idea of +independent columns and the number of + + align:start position:0% +independent columns and the number of + + + align:start position:0% +independent columns and the number of +independent columns is is the rank so + + align:start position:0% +independent columns is is the rank so + + + align:start position:0% +independent columns is is the rank so +the rank shall I write that somewhere + + align:start position:0% +the rank shall I write that somewhere + + + align:start position:0% +the rank shall I write that somewhere +maybe here the rank is the number of + + align:start position:0% +maybe here the rank is the number of + + + align:start position:0% +maybe here the rank is the number of +independent columns + + align:start position:0% + + + + align:start position:0% + +and right now what do I mean by + + align:start position:0% +and right now what do I mean by + + + align:start position:0% +and right now what do I mean by +independent columns well let's just see + + align:start position:0% +independent columns well let's just see + + + align:start position:0% +independent columns well let's just see +what that means by by using it are we + + align:start position:0% +what that means by by using it are we + + + align:start position:0% +what that means by by using it are we +good I'm I know I'm reviewing here but + + align:start position:0% +good I'm I know I'm reviewing here but + + + align:start position:0% +good I'm I know I'm reviewing here but +allow me for this first class and part + + align:start position:0% +allow me for this first class and part + + + align:start position:0% +allow me for this first class and part +of next time also to review but you'll + + align:start position:0% +of next time also to review but you'll + + + align:start position:0% +of next time also to review but you'll +see something new fact why don't we see + + align:start position:0% +see something new fact why don't we see + + + align:start position:0% +see something new fact why don't we see +something new right away let me follow + + align:start position:0% +something new right away let me follow + + + align:start position:0% +something new right away let me follow +up on the idea of Independence in a + + align:start position:0% +up on the idea of Independence in a + + + align:start position:0% +up on the idea of Independence in a +systematic way so here's my matrix a can + + align:start position:0% + + + + align:start position:0% + +I write that again two three five one + + align:start position:0% +I write that again two three five one + + + align:start position:0% +I write that again two three five one +one seven and this guy was the sum of + + align:start position:0% +one seven and this guy was the sum of + + + align:start position:0% +one seven and this guy was the sum of +those okay so that's my matrix a ok so + + align:start position:0% +those okay so that's my matrix a ok so + + + align:start position:0% +those okay so that's my matrix a ok so +let's start from scratch and find a + + align:start position:0% +let's start from scratch and find a + + + align:start position:0% +let's start from scratch and find a +basis for the column space in in the + + align:start position:0% +basis for the column space in in the + + + align:start position:0% +basis for the column space in in the +most natural way so I'm going to take a + + align:start position:0% +most natural way so I'm going to take a + + + align:start position:0% +most natural way so I'm going to take a +basis I'm going to what's a basis a + + align:start position:0% +basis I'm going to what's a basis a + + + align:start position:0% +basis I'm going to what's a basis a +basis is independent columns so all + + align:start position:0% +basis is independent columns so all + + + align:start position:0% +basis is independent columns so all +three together would not be a basis but + + align:start position:0% +three together would not be a basis but + + + align:start position:0% +three together would not be a basis but +there have to be not just independent + + align:start position:0% +there have to be not just independent + + + align:start position:0% +there have to be not just independent +but but they have to fill the space + + align:start position:0% +but but they have to fill the space + + + align:start position:0% +but but they have to fill the space +their combinations have to fill the + + align:start position:0% +their combinations have to fill the + + + align:start position:0% +their combinations have to fill the +space so so two three five can let's say + + align:start position:0% +space so so two three five can let's say + + + align:start position:0% +space so so two three five can let's say +I want to create a basis I'll call the + + align:start position:0% +I want to create a basis I'll call the + + + align:start position:0% +I want to create a basis I'll call the +matrix C column a basis for the column + + align:start position:0% +matrix C column a basis for the column + + + align:start position:0% +matrix C column a basis for the column +space so here's a natural way to do it I + + align:start position:0% +space so here's a natural way to do it I + + + align:start position:0% +space so here's a natural way to do it I +look at the first column it's not zeros + + align:start position:0% +look at the first column it's not zeros + + + align:start position:0% +look at the first column it's not zeros +if it was all zeros I wouldn't want that + + align:start position:0% +if it was all zeros I wouldn't want that + + + align:start position:0% +if it was all zeros I wouldn't want that +in a basis but it's not so I put it in + + align:start position:0% +in a basis but it's not so I put it in + + + align:start position:0% +in a basis but it's not so I put it in +so that's the first vector in my basis + + align:start position:0% +so that's the first vector in my basis + + + align:start position:0% +so that's the first vector in my basis +then I go on to the second column if + + align:start position:0% +then I go on to the second column if + + + align:start position:0% +then I go on to the second column if +that column was four six ten what would + + align:start position:0% +that column was four six ten what would + + + align:start position:0% +that column was four six ten what would +I do if that second column was four six + + align:start position:0% +I do if that second column was four six + + + align:start position:0% +I do if that second column was four six +ten would I put it in the basis no but + + align:start position:0% +ten would I put it in the basis no but + + + align:start position:0% +ten would I put it in the basis no but +one one seven is okay right one one + + align:start position:0% +one one seven is okay right one one + + + align:start position:0% +one one seven is okay right one one +seven is + + align:start position:0% +seven is + + + align:start position:0% +seven is +different direction it's not a + + align:start position:0% +different direction it's not a + + + align:start position:0% +different direction it's not a +combination of what we've already got so + + align:start position:0% +combination of what we've already got so + + + align:start position:0% +combination of what we've already got so +I say okay that adds something new put + + align:start position:0% +I say okay that adds something new put + + + align:start position:0% +I say okay that adds something new put +it in then I move on to the third column + + align:start position:0% +it in then I move on to the third column + + + align:start position:0% +it in then I move on to the third column +do I put that into a basis you know the + + align:start position:0% +do I put that into a basis you know the + + + align:start position:0% +do I put that into a basis you know the +answer by now no because I'm looking to + + align:start position:0% +answer by now no because I'm looking to + + + align:start position:0% +answer by now no because I'm looking to +see is it a combination of these guys + + align:start position:0% +see is it a combination of these guys + + + align:start position:0% +see is it a combination of these guys +and it is it's one of that plus one of + + align:start position:0% +and it is it's one of that plus one of + + + align:start position:0% +and it is it's one of that plus one of +that so it's not independent so I've + + align:start position:0% +that so it's not independent so I've + + + align:start position:0% +that so it's not independent so I've +I've finished now I've got a matrix C + + align:start position:0% +I've finished now I've got a matrix C + + + align:start position:0% +I've finished now I've got a matrix C +which was like taken directly from a and + + align:start position:0% +which was like taken directly from a and + + + align:start position:0% +which was like taken directly from a and +I kept only independent columns and I + + align:start position:0% +I kept only independent columns and I + + + align:start position:0% +I kept only independent columns and I +worked from left to right and I can see + + align:start position:0% +worked from left to right and I can see + + + align:start position:0% +worked from left to right and I can see +that right away now that the rank is to + + align:start position:0% +that right away now that the rank is to + + + align:start position:0% +that right away now that the rank is to +the column rank I should say the column + + align:start position:0% +the column rank I should say the column + + + align:start position:0% +the column rank I should say the column +rank a number of independent columns is + + align:start position:0% +rank a number of independent columns is + + + align:start position:0% +rank a number of independent columns is +too good now comes a key step I'm gonna + + align:start position:0% +too good now comes a key step I'm gonna + + + align:start position:0% +too good now comes a key step I'm gonna +produce a third matrix R which is going + + align:start position:0% +produce a third matrix R which is going + + + align:start position:0% +produce a third matrix R which is going +to tell me how to get these columns from + + align:start position:0% +to tell me how to get these columns from + + + align:start position:0% +to tell me how to get these columns from +these columns and its shape is going to + + align:start position:0% +these columns and its shape is going to + + + align:start position:0% +these columns and its shape is going to +be well its shape I don't have any + + align:start position:0% +be well its shape I don't have any + + + align:start position:0% +be well its shape I don't have any +choice this is 3 by 2 so R has to be to + + align:start position:0% +choice this is 3 by 2 so R has to be to + + + align:start position:0% +choice this is 3 by 2 so R has to be to +buy something so so so I'm like so I + + align:start position:0% +buy something so so so I'm like so I + + + align:start position:0% +buy something so so so I'm like so I +guess it has to be 2 by 3 because I want + + align:start position:0% +guess it has to be 2 by 3 because I want + + + align:start position:0% +guess it has to be 2 by 3 because I want +to come out this way 2 by 3 what am I + + align:start position:0% +to come out this way 2 by 3 what am I + + + align:start position:0% +to come out this way 2 by 3 what am I +gonna do here I'm just going to put in + + align:start position:0% +gonna do here I'm just going to put in + + + align:start position:0% +gonna do here I'm just going to put in +the numbers are that make this correct + + align:start position:0% + + + + align:start position:0% + +so this is a first matrix factorization + + align:start position:0% +so this is a first matrix factorization + + + align:start position:0% +so this is a first matrix factorization +it's not well it is a famous one + + align:start position:0% +it's not well it is a famous one + + + align:start position:0% +it's not well it is a famous one +actually when we see it we'll recognize + + align:start position:0% +actually when we see it we'll recognize + + + align:start position:0% +actually when we see it we'll recognize +what it is it's but it's famous in + + align:start position:0% +what it is it's but it's famous in + + + align:start position:0% +what it is it's but it's famous in +teaching the near algebra but now + + align:start position:0% +teaching the near algebra but now + + + align:start position:0% +teaching the near algebra but now +actually see times are columns times + + align:start position:0% +actually see times are columns times + + + align:start position:0% +actually see times are columns times +rows has become very very important in + + align:start position:0% +rows has become very very important in + + + align:start position:0% +rows has become very very important in +large scale numerical linear algebra + + align:start position:0% +large scale numerical linear algebra + + + align:start position:0% +large scale numerical linear algebra +yeah so let's figure out what goes into + + align:start position:0% +yeah so let's figure out what goes into + + + align:start position:0% +yeah so let's figure out what goes into +our okay so what's going in what am I + + align:start position:0% +our okay so what's going in what am I + + + align:start position:0% +our okay so what's going in what am I +thinking here I'm putting in our that + + align:start position:0% +thinking here I'm putting in our that + + + align:start position:0% +thinking here I'm putting in our that +tel so every one of these columns is a + + align:start position:0% +tel so every one of these columns is a + + + align:start position:0% +tel so every one of these columns is a +combination of these that's the whole + + align:start position:0% +combination of these that's the whole + + + align:start position:0% +combination of these that's the whole +point and I'm just going to put in the + + align:start position:0% +point and I'm just going to put in the + + + align:start position:0% +point and I'm just going to put in the +numbers that you need so what goes in + + align:start position:0% +numbers that you need so what goes in + + + align:start position:0% +numbers that you need so what goes in +the first column of our what goes in the + + align:start position:0% +the first column of our what goes in the + + + align:start position:0% +the first column of our what goes in the +first column of our so I want to look + + align:start position:0% +first column of our so I want to look + + + align:start position:0% +first column of our so I want to look +what combination of that column and that + + align:start position:0% +what combination of that column and that + + + align:start position:0% +what combination of that column and that +column gives me this one yeah one zero + + align:start position:0% +column gives me this one yeah one zero + + + align:start position:0% +column gives me this one yeah one zero +one zero because you remember how we + + align:start position:0% +one zero because you remember how we + + + align:start position:0% +one zero because you remember how we +multiply a matrix by a vector when I + + align:start position:0% +multiply a matrix by a vector when I + + + align:start position:0% +multiply a matrix by a vector when I +multiply that matrix by that vector I + + align:start position:0% +multiply that matrix by that vector I + + + align:start position:0% +multiply that matrix by that vector I +take one of this plus zero of that I see + + align:start position:0% +take one of this plus zero of that I see + + + align:start position:0% +take one of this plus zero of that I see +it vector wise and of course I get it + + align:start position:0% +it vector wise and of course I get it + + + align:start position:0% +it vector wise and of course I get it +right and what about the second column + + align:start position:0% +right and what about the second column + + + align:start position:0% +right and what about the second column +of R so the second column should be the + + align:start position:0% +of R so the second column should be the + + + align:start position:0% +of R so the second column should be the +combination that produces the second + + align:start position:0% +combination that produces the second + + + align:start position:0% +combination that produces the second +column of a correctly what will that be + + align:start position:0% +column of a correctly what will that be + + + align:start position:0% +column of a correctly what will that be +zero one thanks and finally the third + + align:start position:0% +zero one thanks and finally the third + + + align:start position:0% +zero one thanks and finally the third +column one one yes right because one of + + align:start position:0% +column one one yes right because one of + + + align:start position:0% +column one one yes right because one of +this plus one of this produces the third + + align:start position:0% +this plus one of this produces the third + + + align:start position:0% +this plus one of this produces the third +column so so all I did was put in the + + align:start position:0% +column so so all I did was put in the + + + align:start position:0% +column so so all I did was put in the +right numbers there really right and + + align:start position:0% +right numbers there really right and + + + align:start position:0% +right numbers there really right and +this is correct now a SC times R and so + + align:start position:0% +this is correct now a SC times R and so + + + align:start position:0% +this is correct now a SC times R and so +that's this is like what I've done here + + align:start position:0% +that's this is like what I've done here + + + align:start position:0% +that's this is like what I've done here +is like the first two pages of section + + align:start position:0% +is like the first two pages of section + + + align:start position:0% +is like the first two pages of section +1.1 in these notes so 1.1 and actually + + align:start position:0% +1.1 in these notes so 1.1 and actually + + + align:start position:0% +1.1 in these notes so 1.1 and actually +so I tell you literally what happened + + align:start position:0% +so I tell you literally what happened + + + align:start position:0% +so I tell you literally what happened +earlier this year I wish this I wrote I + + align:start position:0% +earlier this year I wish this I wrote I + + + align:start position:0% +earlier this year I wish this I wrote I +wrote this down with a different example + + align:start position:0% +wrote this down with a different example + + + align:start position:0% +wrote this down with a different example +and then I realized something that that + + align:start position:0% +and then I realized something that that + + + align:start position:0% +and then I realized something that that +sitting here in front of me was the + + align:start position:0% +sitting here in front of me was the + + + align:start position:0% +sitting here in front of me was the +first great theorem in linear algebra + + align:start position:0% +first great theorem in linear algebra + + + align:start position:0% +first great theorem in linear algebra +the fact that the column rank equals the + + align:start position:0% +the fact that the column rank equals the + + + align:start position:0% +the fact that the column rank equals the +row rank the fact that if I have a + + align:start position:0% +row rank the fact that if I have a + + + align:start position:0% +row rank the fact that if I have a +matrix where that column plus that + + align:start position:0% +matrix where that column plus that + + + align:start position:0% +matrix where that column plus that +column gives that one oh so what am I + + align:start position:0% +column gives that one oh so what am I + + + align:start position:0% +column gives that one oh so what am I +going to say here I'm getting nervous + + align:start position:0% +going to say here I'm getting nervous + + + align:start position:0% +going to say here I'm getting nervous +about it I believe that a combination of + + align:start position:0% +about it I believe that a combination of + + + align:start position:0% +about it I believe that a combination of +the rows gives 0 do you believe that I + + align:start position:0% +the rows gives 0 do you believe that I + + + align:start position:0% +the rows gives 0 do you believe that I +mean you got to believe it this is like + + align:start position:0% +mean you got to believe it this is like + + + align:start position:0% +mean you got to believe it this is like +a linear algebra the matrix is not + + align:start position:0% +a linear algebra the matrix is not + + + align:start position:0% +a linear algebra the matrix is not +invertible it's square but the columns + + align:start position:0% +invertible it's square but the columns + + + align:start position:0% +invertible it's square but the columns +are dependent so the rows have to be + + align:start position:0% +are dependent so the rows have to be + + + align:start position:0% +are dependent so the rows have to be +dependent and I don't exactly see I + + align:start position:0% +dependent and I don't exactly see I + + + align:start position:0% +dependent and I don't exactly see I +there's some combination of that row and + + align:start position:0% +there's some combination of that row and + + + align:start position:0% +there's some combination of that row and +that row that gives that one and when I + + align:start position:0% +that row that gives that one and when I + + + align:start position:0% +that row that gives that one and when I +of course when I looked at the first + + align:start position:0% +of course when I looked at the first + + + align:start position:0% +of course when I looked at the first +column I thought ok it's going to be + + align:start position:0% +column I thought ok it's going to be + + + align:start position:0% +column I thought ok it's going to be +it's going to be too easy one of that + + align:start position:0% +it's going to be too easy one of that + + + align:start position:0% +it's going to be too easy one of that +and one of that gives that but then my I + + align:start position:0% +and one of that gives that but then my I + + + align:start position:0% +and one of that gives that but then my I +went over to the second column and I + + align:start position:0% +went over to the second column and I + + + align:start position:0% +went over to the second column and I +realize it's not easy at all so you're + + align:start position:0% +realize it's not easy at all so you're + + + align:start position:0% +realize it's not easy at all so you're +entitled to pull out a your phone and + + align:start position:0% +entitled to pull out a your phone and + + + align:start position:0% +entitled to pull out a your phone and +figure this out but there is some damn + + align:start position:0% +figure this out but there is some damn + + + align:start position:0% +figure this out but there is some damn +combination of those of those two rows + + align:start position:0% +combination of those of those two rows + + + align:start position:0% +combination of those of those two rows +it gives the third row it's otherwise + + align:start position:0% +it gives the third row it's otherwise + + + align:start position:0% +it gives the third row it's otherwise +like the course is over we stop but well + + align:start position:0% +like the course is over we stop but well + + + align:start position:0% +like the course is over we stop but well +maybe we're gonna find it or somehow + + align:start position:0% +maybe we're gonna find it or somehow + + + align:start position:0% +maybe we're gonna find it or somehow +yeah yeah so so that's this is the + + align:start position:0% +yeah yeah so so that's this is the + + + align:start position:0% +yeah yeah so so that's this is the +theorem so I so I have to tell you I + + align:start position:0% +theorem so I so I have to tell you I + + + align:start position:0% +theorem so I so I have to tell you I +mean you know I was like really pleased + + align:start position:0% +mean you know I was like really pleased + + + align:start position:0% +mean you know I was like really pleased +so the first two pages got two more + + align:start position:0% +so the first two pages got two more + + + align:start position:0% +so the first two pages got two more +pages to follow up on that idea that + + align:start position:0% +pages to follow up on that idea that + + + align:start position:0% +pages to follow up on that idea that +here we were seeing something that I + + align:start position:0% +here we were seeing something that I + + + align:start position:0% +here we were seeing something that I +sort of proved in 1806 but not you know + + align:start position:0% +sort of proved in 1806 but not you know + + + align:start position:0% +sort of proved in 1806 but not you know +not in the first lecture that's for sure + + align:start position:0% +not in the first lecture that's for sure + + + align:start position:0% +not in the first lecture that's for sure +and I'm not not maybe so clearly but now + + align:start position:0% +and I'm not not maybe so clearly but now + + + align:start position:0% +and I'm not not maybe so clearly but now +I can I try to prove it + + align:start position:0% +I can I try to prove it + + + align:start position:0% +I can I try to prove it +so and so here's the there won't be a + + align:start position:0% +so and so here's the there won't be a + + + align:start position:0% +so and so here's the there won't be a +lot of proofs in this class but this is + + align:start position:0% +lot of proofs in this class but this is + + + align:start position:0% +lot of proofs in this class but this is +such an important fact a equals CR is + + align:start position:0% +such an important fact a equals CR is + + + align:start position:0% +such an important fact a equals CR is +important factorization and and out of + + align:start position:0% +important factorization and and out of + + + align:start position:0% +important factorization and and out of +it we can connect them so what am I + + align:start position:0% +it we can connect them so what am I + + + align:start position:0% +it we can connect them so what am I +saying I'm saying that all that that + + align:start position:0% +saying I'm saying that all that that + + + align:start position:0% +saying I'm saying that all that that +that the row so what's the row rank yeah + + align:start position:0% +that the row so what's the row rank yeah + + + align:start position:0% +that the row so what's the row rank yeah +I could go back up here what's the row + + align:start position:0% +I could go back up here what's the row + + + align:start position:0% +I could go back up here what's the row +rank what's the row space so the row + + align:start position:0% +rank what's the row space so the row + + + align:start position:0% +rank what's the row space so the row +rank is going to be the definite the + + align:start position:0% +rank is going to be the definite the + + + align:start position:0% +rank is going to be the definite the +dimension of that space so so I look at + + align:start position:0% +dimension of that space so so I look at + + + align:start position:0% +dimension of that space so so I look at +my matrix a what's the row space of a + + align:start position:0% + + + + align:start position:0% + +I'm gonna look at its rows now maybe + + align:start position:0% +I'm gonna look at its rows now maybe + + + align:start position:0% +I'm gonna look at its rows now maybe +just so we don't get a whole new letters + + align:start position:0% +just so we don't get a whole new letters + + + align:start position:0% +just so we don't get a whole new letters +for the row space there I'm for me the + + align:start position:0% +for the row space there I'm for me the + + + align:start position:0% +for the row space there I'm for me the +row space of a of a matrix so so first + + align:start position:0% +row space of a of a matrix so so first + + + align:start position:0% +row space of a of a matrix so so first +of all tell me in words what it is + + align:start position:0% +of all tell me in words what it is + + + align:start position:0% +of all tell me in words what it is +what's the row space of the matrix all + + align:start position:0% +what's the row space of the matrix all + + + align:start position:0% +what's the row space of the matrix all +combinations of the rows all + + align:start position:0% +combinations of the rows all + + + align:start position:0% +combinations of the rows all +combinations of the rows that's the + + align:start position:0% +combinations of the rows that's the + + + align:start position:0% +combinations of the rows that's the +space so I would take all combinations + + align:start position:0% +space so I would take all combinations + + + align:start position:0% +space so I would take all combinations +of those rows to get combinations of the + + align:start position:0% +of those rows to get combinations of the + + + align:start position:0% +of those rows to get combinations of the +rows I well two ways I can get + + align:start position:0% +rows I well two ways I can get + + + align:start position:0% +rows I well two ways I can get +combinations of the rows and the way + + align:start position:0% +combinations of the rows and the way + + + align:start position:0% +combinations of the rows and the way +I'll do it is + + align:start position:0% +I'll do it is + + + align:start position:0% +I'll do it is +I'll just transpose the matrix so those + + align:start position:0% +I'll just transpose the matrix so those + + + align:start position:0% +I'll just transpose the matrix so those +rows become columns and then I'm back to + + align:start position:0% +rows become columns and then I'm back to + + + align:start position:0% +rows become columns and then I'm back to +what I did so the row space of a is the + + align:start position:0% +what I did so the row space of a is the + + + align:start position:0% +what I did so the row space of a is the +column space of a transpose and and this + + align:start position:0% +column space of a transpose and and this + + + align:start position:0% +column space of a transpose and and this +has the advantage that we don't + + align:start position:0% +has the advantage that we don't + + + align:start position:0% +has the advantage that we don't +introduce a new letter so it's it'll be + + align:start position:0% +introduce a new letter so it's it'll be + + + align:start position:0% +introduce a new letter so it's it'll be +the column space of a transpose so we + + align:start position:0% +the column space of a transpose so we + + + align:start position:0% +the column space of a transpose so we +don't introduce a new letter we keep the + + align:start position:0% +don't introduce a new letter we keep the + + + align:start position:0% +don't introduce a new letter we keep the +convention that vectors are column + + align:start position:0% +convention that vectors are column + + + align:start position:0% +convention that vectors are column +vectors which would be the MATLAB and + + align:start position:0% +vectors which would be the MATLAB and + + + align:start position:0% +vectors which would be the MATLAB and +and Julia and Python convention so is + + align:start position:0% +and Julia and Python convention so is + + + align:start position:0% +and Julia and Python convention so is +that okay + + align:start position:0% +that okay + + + align:start position:0% +that okay +the row space is the combination of + + align:start position:0% +the row space is the combination of + + + align:start position:0% +the row space is the combination of +these rows but I'll flip i'll make them + + align:start position:0% +these rows but I'll flip i'll make them + + + align:start position:0% +these rows but I'll flip i'll make them +stand up 2 1 3 2 2 B column vectors so + + align:start position:0% +stand up 2 1 3 2 2 B column vectors so + + + align:start position:0% +stand up 2 1 3 2 2 B column vectors so +it's a totally different space and + + align:start position:0% +it's a totally different space and + + + align:start position:0% +it's a totally different space and +actually in my I happen to take a 3 by 3 + + align:start position:0% +actually in my I happen to take a 3 by 3 + + + align:start position:0% +actually in my I happen to take a 3 by 3 +example so that the column space is part + + align:start position:0% +example so that the column space is part + + + align:start position:0% +example so that the column space is part +of our three and the row space is also + + align:start position:0% +of our three and the row space is also + + + align:start position:0% +of our three and the row space is also +part of our three because my matrix is + + align:start position:0% +part of our three because my matrix is + + + align:start position:0% +part of our three because my matrix is +three by three a better example I mean + + align:start position:0% +three by three a better example I mean + + + align:start position:0% +three by three a better example I mean +and the whole point of data data doesn't + + align:start position:0% +and the whole point of data data doesn't + + + align:start position:0% +and the whole point of data data doesn't +come in square matrices fortunately for + + align:start position:0% +come in square matrices fortunately for + + + align:start position:0% +come in square matrices fortunately for +us data very very often comes in + + align:start position:0% +us data very very often comes in + + + align:start position:0% +us data very very often comes in +matrices but the to the columns might be + + align:start position:0% +matrices but the to the columns might be + + + align:start position:0% +matrices but the to the columns might be +sampled might be patients and the rows + + align:start position:0% +sampled might be patients and the rows + + + align:start position:0% +sampled might be patients and the rows +might be diseases or something I mean + + align:start position:0% +might be diseases or something I mean + + + align:start position:0% +might be diseases or something I mean +they're they're different spaces so + + align:start position:0% +they're they're different spaces so + + + align:start position:0% +they're they're different spaces so +matrices are not likely to be square but + + align:start position:0% +matrices are not likely to be square but + + + align:start position:0% +matrices are not likely to be square but +anyway we're good here okay okay so the + + align:start position:0% +anyway we're good here okay okay so the + + + align:start position:0% +anyway we're good here okay okay so the +row space + + align:start position:0% +row space + + + align:start position:0% +row space +now now can I come back to the proof + + align:start position:0% +now now can I come back to the proof + + + align:start position:0% +now now can I come back to the proof +because we what I want to say is that + + align:start position:0% +because we what I want to say is that + + + align:start position:0% +because we what I want to say is that +the proof of this fundamental fact is + + align:start position:0% +the proof of this fundamental fact is + + + align:start position:0% +the proof of this fundamental fact is +staring at us but we don't quite see it + + align:start position:0% +staring at us but we don't quite see it + + + align:start position:0% +staring at us but we don't quite see it +yet and I want to see it so I claim that + + align:start position:0% + + + + align:start position:0% + +these rows are a basis for the row space + + align:start position:0% +these rows are a basis for the row space + + + align:start position:0% +these rows are a basis for the row space +and we already saw that these columns + + align:start position:0% +and we already saw that these columns + + + align:start position:0% +and we already saw that these columns +our basis for the column space and two + + align:start position:0% +our basis for the column space and two + + + align:start position:0% +our basis for the column space and two +equals two right two vectors here or a + + align:start position:0% +equals two right two vectors here or a + + + align:start position:0% +equals two right two vectors here or a +basis for the column space now if I can + + align:start position:0% +basis for the column space now if I can + + + align:start position:0% +basis for the column space now if I can +see why this shows me that these two + + align:start position:0% +see why this shows me that these two + + + align:start position:0% +see why this shows me that these two +vectors are a basis for the row space + + align:start position:0% +vectors are a basis for the row space + + + align:start position:0% +vectors are a basis for the row space +then then I have my example is right + + align:start position:0% +then then I have my example is right + + + align:start position:0% +then then I have my example is right +both both of these will give to the + + align:start position:0% +both both of these will give to the + + + align:start position:0% +both both of these will give to the +column rank is to two columns the row + + align:start position:0% +column rank is to two columns the row + + + align:start position:0% +column rank is to two columns the row +rank is to two rows so + + align:start position:0% +rank is to two rows so + + + align:start position:0% +rank is to two rows so +I have to explain why I believe that + + align:start position:0% +I have to explain why I believe that + + + align:start position:0% +I have to explain why I believe that +these two rows are a basis for the row + + align:start position:0% +these two rows are a basis for the row + + + align:start position:0% +these two rows are a basis for the row +space right with me I have to prove to + + align:start position:0% +space right with me I have to prove to + + + align:start position:0% +space right with me I have to prove to +see why first are there so when I say + + align:start position:0% +see why first are there so when I say + + + align:start position:0% +see why first are there so when I say +basis what do I have to check basis is + + align:start position:0% +basis what do I have to check basis is + + + align:start position:0% +basis what do I have to check basis is +is just is the critical idea it I have + + align:start position:0% +is just is the critical idea it I have + + + align:start position:0% +is just is the critical idea it I have +to check that they're independent so I + + align:start position:0% +to check that they're independent so I + + + align:start position:0% +to check that they're independent so I +haven't got too many vectors I've got + + align:start position:0% +haven't got too many vectors I've got + + + align:start position:0% +haven't got too many vectors I've got +any extra vectors in there and I also + + align:start position:0% +any extra vectors in there and I also + + + align:start position:0% +any extra vectors in there and I also +have to check that their combinations + + align:start position:0% +have to check that their combinations + + + align:start position:0% +have to check that their combinations +produce all the rows should I say that + + align:start position:0% +produce all the rows should I say that + + + align:start position:0% +produce all the rows should I say that +again that's because that's what I'm + + align:start position:0% +again that's because that's what I'm + + + align:start position:0% +again that's because that's what I'm +going to check I'm gonna check that + + align:start position:0% +going to check I'm gonna check that + + + align:start position:0% +going to check I'm gonna check that +those guys are independent well you can + + align:start position:0% +those guys are independent well you can + + + align:start position:0% +those guys are independent well you can +see that they're independent and I'm + + align:start position:0% +see that they're independent and I'm + + + align:start position:0% +see that they're independent and I'm +going to check that the that their + + align:start position:0% +going to check that the that their + + + align:start position:0% +going to check that the that their +combinations produce all three of these + + align:start position:0% +combinations produce all three of these + + + align:start position:0% +combinations produce all three of these +rows if we didn't create those numbers + + align:start position:0% +rows if we didn't create those numbers + + + align:start position:0% +rows if we didn't create those numbers +for this purpose but what I'm saying is + + align:start position:0% +for this purpose but what I'm saying is + + + align:start position:0% +for this purpose but what I'm saying is +they work so I claim that this is a + + align:start position:0% +they work so I claim that this is a + + + align:start position:0% +they work so I claim that this is a +basis because what what combination of + + align:start position:0% +basis because what what combination of + + + align:start position:0% +basis because what what combination of +those two rows would produce this this + + align:start position:0% +those two rows would produce this this + + + align:start position:0% +those two rows would produce this this +first row yeah let me just ask you that + + align:start position:0% +first row yeah let me just ask you that + + + align:start position:0% +first row yeah let me just ask you that +what combination what numbers should I + + align:start position:0% +what combination what numbers should I + + + align:start position:0% +what combination what numbers should I +multiply these two rows by to get the + + align:start position:0% +multiply these two rows by to get the + + + align:start position:0% +multiply these two rows by to get the +first row of any two and one and where + + align:start position:0% +first row of any two and one and where + + + align:start position:0% +first row of any two and one and where +do you find two and one + + align:start position:0% +do you find two and one + + + align:start position:0% +do you find two and one +it's sitting there in see what I'm and + + align:start position:0% +it's sitting there in see what I'm and + + + align:start position:0% +it's sitting there in see what I'm and +will it work again does three of this + + align:start position:0% +will it work again does three of this + + + align:start position:0% +will it work again does three of this +plus one of that give three one four yes + + align:start position:0% +plus one of that give three one four yes + + + align:start position:0% +plus one of that give three one four yes +so far so good + + align:start position:0% +so far so good + + + align:start position:0% +so far so good +does five of this and seven of that see + + align:start position:0% +does five of this and seven of that see + + + align:start position:0% +does five of this and seven of that see +I'm multiplying I guess I'm doing matrix + + align:start position:0% +I'm multiplying I guess I'm doing matrix + + + align:start position:0% +I'm multiplying I guess I'm doing matrix +multiplication a sort of backward wait + + align:start position:0% +multiplication a sort of backward wait + + + align:start position:0% +multiplication a sort of backward wait +or a different different way I'm taking + + align:start position:0% +or a different different way I'm taking + + + align:start position:0% +or a different different way I'm taking +combinations of the rows of the second + + align:start position:0% +combinations of the rows of the second + + + align:start position:0% +combinations of the rows of the second +guy that's another way that one + + align:start position:0% +guy that's another way that one + + + align:start position:0% +guy that's another way that one +careful thing about matrix + + align:start position:0% +careful thing about matrix + + + align:start position:0% +careful thing about matrix +multiplication is you can do it a lot of + + align:start position:0% +multiplication is you can do it a lot of + + + align:start position:0% +multiplication is you can do it a lot of +ways it comes out the same every way and + + align:start position:0% +ways it comes out the same every way and + + + align:start position:0% +ways it comes out the same every way and +each way tells you something so 5 of + + align:start position:0% +each way tells you something so 5 of + + + align:start position:0% +each way tells you something so 5 of +that row plus 7 of that row sure enough + + align:start position:0% +that row plus 7 of that row sure enough + + + align:start position:0% +that row plus 7 of that row sure enough +is here do you see that that is not like + + align:start position:0% +is here do you see that that is not like + + + align:start position:0% +is here do you see that that is not like +accident that that the proof is really + + align:start position:0% +accident that that the proof is really + + + align:start position:0% +accident that that the proof is really +to look at this multiplication C times + + align:start position:0% +to look at this multiplication C times + + + align:start position:0% +to look at this multiplication C times +are two ways look at it first as + + align:start position:0% +are two ways look at it first as + + + align:start position:0% +are two ways look at it first as +combinations of columns of C to give the + + align:start position:0% +combinations of columns of C to give the + + + align:start position:0% +combinations of columns of C to give the +columns look at it second to get as + + align:start position:0% +columns look at it second to get as + + + align:start position:0% +columns look at it second to get as +combinations of the rows of R and that + + align:start position:0% +combinations of the rows of R and that + + + align:start position:0% +combinations of the rows of R and that +produces the rows so that factorization + + align:start position:0% +produces the rows so that factorization + + + align:start position:0% +produces the rows so that factorization +a equals C R was what's the key idea and + + align:start position:0% +a equals C R was what's the key idea and + + + align:start position:0% +a equals C R was what's the key idea and +actually this R that we've come up with + + align:start position:0% + + + + align:start position:0% + +has a name + + align:start position:0% +has a name + + + align:start position:0% +has a name +anybody remember enough 1806 here's a + + align:start position:0% +anybody remember enough 1806 here's a + + + align:start position:0% +anybody remember enough 1806 here's a +like have you all taken 1806 I'm no I + + align:start position:0% +like have you all taken 1806 I'm no I + + + align:start position:0% +like have you all taken 1806 I'm no I +see us how many have let's yes okay good + + align:start position:0% + + + + align:start position:0% + +for a while 1806 was taught in a very + + align:start position:0% +for a while 1806 was taught in a very + + + align:start position:0% +for a while 1806 was taught in a very +abstract way I said what's going on but + + align:start position:0% +abstract way I said what's going on but + + + align:start position:0% +abstract way I said what's going on but +anyway so if you took it that semester + + align:start position:0% +anyway so if you took it that semester + + + align:start position:0% +anyway so if you took it that semester +you maybe never heard of the column + + align:start position:0% +you maybe never heard of the column + + + align:start position:0% +you maybe never heard of the column +space I'm not sure or by a different + + align:start position:0% +space I'm not sure or by a different + + + align:start position:0% +space I'm not sure or by a different +name it has another name + + align:start position:0% +name it has another name + + + align:start position:0% +name it has another name +what's its other name the column space + + align:start position:0% +what's its other name the column space + + + align:start position:0% +what's its other name the column space +of a matrix range I think it's the range + + align:start position:0% +of a matrix range I think it's the range + + + align:start position:0% +of a matrix range I think it's the range +yeah right right yep yep and of course + + align:start position:0% +yeah right right yep yep and of course + + + align:start position:0% +yeah right right yep yep and of course +it's all this is fundamental in + + align:start position:0% +it's all this is fundamental in + + + align:start position:0% +it's all this is fundamental in +mathematics so of course it everything + + align:start position:0% +mathematics so of course it everything + + + align:start position:0% +mathematics so of course it everything +here is is has different languages and + + align:start position:0% +here is is has different languages and + + + align:start position:0% +here is is has different languages and +different emphasis but you see what the + + align:start position:0% +different emphasis but you see what the + + + align:start position:0% +different emphasis but you see what the +emphasis is here okay so you see the + + align:start position:0% +emphasis is here okay so you see the + + + align:start position:0% +emphasis is here okay so you see the +proof that a equals C R is just reveals + + align:start position:0% +proof that a equals C R is just reveals + + + align:start position:0% +proof that a equals C R is just reveals +everything so it's a first idea of a + + align:start position:0% +everything so it's a first idea of a + + + align:start position:0% +everything so it's a first idea of a +factorization of a matrix + + align:start position:0% +factorization of a matrix + + + align:start position:0% +factorization of a matrix +and and we've multiplied see times are + + align:start position:0% +and and we've multiplied see times are + + + align:start position:0% +and and we've multiplied see times are +now I could just say cuz so that's + + align:start position:0% +now I could just say cuz so that's + + + align:start position:0% +now I could just say cuz so that's +really you've seen the now the main + + align:start position:0% +really you've seen the now the main + + + align:start position:0% +really you've seen the now the main +point of section 1.1 of the notes to + + align:start position:0% +point of section 1.1 of the notes to + + + align:start position:0% +point of section 1.1 of the notes to +come up with that factorization and that + + align:start position:0% +come up with that factorization and that + + + align:start position:0% +come up with that factorization and that +conclusion and and and you see why C has + + align:start position:0% +conclusion and and and you see why C has + + + align:start position:0% +conclusion and and and you see why C has +the same number of the number of columns + + align:start position:0% +the same number of the number of columns + + + align:start position:0% +the same number of the number of columns +of C will the number of rows of our and + + align:start position:0% +of C will the number of rows of our and + + + align:start position:0% +of C will the number of rows of our and +those are the column rank and the row + + align:start position:0% +those are the column rank and the row + + + align:start position:0% +those are the column rank and the row +rank yeah it's just pretty neat and here + + align:start position:0% +rank yeah it's just pretty neat and here + + + align:start position:0% +rank yeah it's just pretty neat and here +was the special case where those column + + align:start position:0% +was the special case where those column + + + align:start position:0% +was the special case where those column +space the column space is all multiples + + align:start position:0% +space the column space is all multiples + + + align:start position:0% +space the column space is all multiples +of you it's a line through you the row + + align:start position:0% +of you it's a line through you the row + + + align:start position:0% +of you it's a line through you the row +space is all multiples of V it's a line + + align:start position:0% +space is all multiples of V it's a line + + + align:start position:0% +space is all multiples of V it's a line +through V and that's the basic building + + align:start position:0% +through V and that's the basic building + + + align:start position:0% +through V and that's the basic building +block yeah can I just say another little + + align:start position:0% +block yeah can I just say another little + + + align:start position:0% +block yeah can I just say another little +word before I push on beyond CR that + + align:start position:0% +word before I push on beyond CR that + + + align:start position:0% +word before I push on beyond CR that +that this has become if you have a giant + + align:start position:0% +that this has become if you have a giant + + + align:start position:0% +that this has become if you have a giant +matrix like size 10 to the fifth that's + + align:start position:0% +matrix like size 10 to the fifth that's + + + align:start position:0% +matrix like size 10 to the fifth that's +that you know you can't put that into + + align:start position:0% +that you know you can't put that into + + + align:start position:0% +that you know you can't put that into +fast memory you it's it's it's a mess + + align:start position:0% +fast memory you it's it's it's a mess + + + align:start position:0% +fast memory you it's it's it's a mess +how do you deal with a matrix of size 10 + + align:start position:0% +how do you deal with a matrix of size 10 + + + align:start position:0% +how do you deal with a matrix of size 10 +to the fifth when you cannot deal with + + align:start position:0% +to the fifth when you cannot deal with + + + align:start position:0% +to the fifth when you cannot deal with +all the entries that that's just not + + align:start position:0% +all the entries that that's just not + + + align:start position:0% +all the entries that that's just not +possible + + align:start position:0% +possible + + + align:start position:0% +possible +will you sample it so later in the + + align:start position:0% +will you sample it so later in the + + + align:start position:0% +will you sample it so later in the +course we'll be doing random sampling of + + align:start position:0% +course we'll be doing random sampling of + + + align:start position:0% +course we'll be doing random sampling of +a matrix so how could your sample a + + align:start position:0% +a matrix so how could your sample a + + + align:start position:0% +a matrix so how could your sample a +matrix so you have a matrix of course + + align:start position:0% +matrix so you have a matrix of course + + + align:start position:0% +matrix so you have a matrix of course +you're not looking at it because but + + align:start position:0% +you're not looking at it because but + + + align:start position:0% +you're not looking at it because but +it's and you want to get some typical + + align:start position:0% +it's and you want to get some typical + + + align:start position:0% +it's and you want to get some typical +columns okay here's the natural idea you + + align:start position:0% +columns okay here's the natural idea you + + + align:start position:0% +columns okay here's the natural idea you +just look at any x x when you take let X + + align:start position:0% +just look at any x x when you take let X + + + align:start position:0% +just look at any x x when you take let X +be a random vector random vector R and R + + align:start position:0% +be a random vector random vector R and R + + + align:start position:0% +be a random vector random vector R and R +and of so it's got M rows and one column + + align:start position:0% +and of so it's got M rows and one column + + + align:start position:0% +and of so it's got M rows and one column +it's a vector and what can I say about + + align:start position:0% +it's a vector and what can I say about + + + align:start position:0% +it's a vector and what can I say about +ax + + align:start position:0% +ax + + + align:start position:0% +ax +it's in what spaces it in column space + + align:start position:0% +it's in what spaces it in column space + + + align:start position:0% +it's in what spaces it in column space +thanks that was the first idea in this + + align:start position:0% +thanks that was the first idea in this + + + align:start position:0% +thanks that was the first idea in this +in this lecture ax is in the column + + align:start position:0% +in this lecture ax is in the column + + + align:start position:0% +in this lecture ax is in the column +space so if you want a random vector in + + align:start position:0% +space so if you want a random vector in + + + align:start position:0% +space so if you want a random vector in +the column space I wouldn't suggest it + + align:start position:0% +the column space I wouldn't suggest it + + + align:start position:0% +the column space I wouldn't suggest it +just randomly pick one of the columns + + align:start position:0% +just randomly pick one of the columns + + + align:start position:0% +just randomly pick one of the columns +better to take a mixture of columns by + + align:start position:0% +better to take a mixture of columns by + + + align:start position:0% +better to take a mixture of columns by +taking a random vector X and looking at + + align:start position:0% +taking a random vector X and looking at + + + align:start position:0% +taking a random vector X and looking at +looking at ax and if you wanted a + + align:start position:0% +looking at ax and if you wanted a + + + align:start position:0% +looking at ax and if you wanted a +hundred random vectors you take a + + align:start position:0% +hundred random vectors you take a + + + align:start position:0% +hundred random vectors you take a +hundred random X's and that would give + + align:start position:0% +hundred random X's and that would give + + + align:start position:0% +hundred random X's and that would give +you a pretty good idea in many cases of + + align:start position:0% +you a pretty good idea in many cases of + + + align:start position:0% +you a pretty good idea in many cases of +what what the column space looks like + + align:start position:0% +what what the column space looks like + + + align:start position:0% +what what the column space looks like +that would be enough to work with often + + align:start position:0% +that would be enough to work with often + + + align:start position:0% +that would be enough to work with often +yeah okay okay can I just throw in + + align:start position:0% +yeah okay okay can I just throw in + + + align:start position:0% +yeah okay okay can I just throw in +another question so so ax is in the + + align:start position:0% +another question so so ax is in the + + + align:start position:0% +another question so so ax is in the +column space of a let me just ask you + + align:start position:0% +column space of a let me just ask you + + + align:start position:0% +column space of a let me just ask you +this question is is ABC X is that in the + + align:start position:0% +this question is is ABC X is that in the + + + align:start position:0% +this question is is ABC X is that in the +column space of a suppose I have + + align:start position:0% +column space of a suppose I have + + + align:start position:0% +column space of a suppose I have +matrices a B and C and a vector X and I + + align:start position:0% +matrices a B and C and a vector X and I + + + align:start position:0% +matrices a B and C and a vector X and I +take their product does that give me + + align:start position:0% +take their product does that give me + + + align:start position:0% +take their product does that give me +something in the column space of a yes + + align:start position:0% +something in the column space of a yes + + + align:start position:0% +something in the column space of a yes +good for you why how do you know that + + align:start position:0% + + + + align:start position:0% + +yeah it's a time something right putting + + align:start position:0% +yeah it's a time something right putting + + + align:start position:0% +yeah it's a time something right putting +parentheses in the right place is the + + align:start position:0% +parentheses in the right place is the + + + align:start position:0% +parentheses in the right place is the +key to linear algebra and they're okay + + align:start position:0% +key to linear algebra and they're okay + + + align:start position:0% +key to linear algebra and they're okay +it's a question just occurred to me and + + align:start position:0% +it's a question just occurred to me and + + + align:start position:0% +it's a question just occurred to me and +I thought well I wonder if you'd do it + + align:start position:0% +I thought well I wonder if you'd do it + + + align:start position:0% +I thought well I wonder if you'd do it +okay so we have still time to multiply + + align:start position:0% +okay so we have still time to multiply + + + align:start position:0% +okay so we have still time to multiply +matrices oh I was going to say about C + + align:start position:0% +matrices oh I was going to say about C + + + align:start position:0% +matrices oh I was going to say about C +and R so these are real columns from a + + align:start position:0% +and R so these are real columns from a + + + align:start position:0% +and R so these are real columns from a +but R is the rows are not taken directly + + align:start position:0% +but R is the rows are not taken directly + + + align:start position:0% +but R is the rows are not taken directly +from the rows of a actually there's a + + align:start position:0% +from the rows of a actually there's a + + + align:start position:0% +from the rows of a actually there's a +name for this it's called the row + + align:start position:0% +name for this it's called the row + + + align:start position:0% +name for this it's called the row +reduced echelon form of the matrix and + + align:start position:0% +reduced echelon form of the matrix and + + + align:start position:0% +reduced echelon form of the matrix and +it's a big goal in in 1806 it has the + + align:start position:0% +it's a big goal in in 1806 it has the + + + align:start position:0% +it's a big goal in in 1806 it has the +identity there and then the other + + align:start position:0% +identity there and then the other + + + align:start position:0% +identity there and then the other +columns are tell you the right + + align:start position:0% +columns are tell you the right + + + align:start position:0% +columns are tell you the right +combinations yep yep another big + + align:start position:0% +combinations yep yep another big + + + align:start position:0% +combinations yep yep another big +factorization would be to take columns + + align:start position:0% +factorization would be to take columns + + + align:start position:0% +factorization would be to take columns +from from a so this is another so I'll + + align:start position:0% +from from a so this is another so I'll + + + align:start position:0% +from from a so this is another so I'll +put maybe or and we won't be doing this + + align:start position:0% +put maybe or and we won't be doing this + + + align:start position:0% +put maybe or and we won't be doing this +for a month + + align:start position:0% +for a month + + + align:start position:0% +for a month +we could start take columns of columns + + align:start position:0% +we could start take columns of columns + + + align:start position:0% +we could start take columns of columns +of a and put them in to see if they were + + align:start position:0% +of a and put them in to see if they were + + + align:start position:0% +of a and put them in to see if they were +independent and suppose I took rows of a + + align:start position:0% +independent and suppose I took rows of a + + + align:start position:0% +independent and suppose I took rows of a +now I'm going to take literally rows of + + align:start position:0% +now I'm going to take literally rows of + + + align:start position:0% +now I'm going to take literally rows of +a and put them into or well so I call it + + align:start position:0% +a and put them into or well so I call it + + + align:start position:0% +a and put them into or well so I call it +our twiddle or something cuz it'll be a + + align:start position:0% +our twiddle or something cuz it'll be a + + + align:start position:0% +our twiddle or something cuz it'll be a +different R I'm gonna use actually not + + align:start position:0% +different R I'm gonna use actually not + + + align:start position:0% +different R I'm gonna use actually not +I'm not going to use those rows but I'm + + align:start position:0% +I'm not going to use those rows but I'm + + + align:start position:0% +I'm not going to use those rows but I'm +gonna take two actual rows of a then + + align:start position:0% +gonna take two actual rows of a then + + + align:start position:0% +gonna take two actual rows of a then +what so that's important factorization + + align:start position:0% +what so that's important factorization + + + align:start position:0% +what so that's important factorization +but it's not correct I wouldn't if I + + align:start position:0% +but it's not correct I wouldn't if I + + + align:start position:0% +but it's not correct I wouldn't if I +took two other rows of our it wouldn't + + align:start position:0% +took two other rows of our it wouldn't + + + align:start position:0% +took two other rows of our it wouldn't +work so you have to put in the middle + + align:start position:0% +work so you have to put in the middle + + + align:start position:0% +work so you have to put in the middle +some two-by-two matrix you that makes it + + align:start position:0% +some two-by-two matrix you that makes it + + + align:start position:0% +some two-by-two matrix you that makes it +correct just you'll see on the in the in + + align:start position:0% +correct just you'll see on the in the in + + + align:start position:0% +correct just you'll see on the in the in +that section 1.1 that I got excited and + + align:start position:0% +that section 1.1 that I got excited and + + + align:start position:0% +that section 1.1 that I got excited and +wrote a page about seeing you are yep + + align:start position:0% +wrote a page about seeing you are yep + + + align:start position:0% +wrote a page about seeing you are yep +solid just mention that okay so now I'm + + align:start position:0% +solid just mention that okay so now I'm + + + align:start position:0% +solid just mention that okay so now I'm +ready oh I wanted to say something about + + align:start position:0% +ready oh I wanted to say something about + + + align:start position:0% +ready oh I wanted to say something about +the course decided thing about mass but + + align:start position:0% +the course decided thing about mass but + + + align:start position:0% +the course decided thing about mass but +there is this course so what's up so + + align:start position:0% +there is this course so what's up so + + + align:start position:0% +there is this course so what's up so +there be linear algebra problems but but + + align:start position:0% +there be linear algebra problems but but + + + align:start position:0% +there be linear algebra problems but but +what makes this course special is the + + align:start position:0% +what makes this course special is the + + + align:start position:0% +what makes this course special is the +other homeworks which are online and you + + align:start position:0% +other homeworks which are online and you + + + align:start position:0% +other homeworks which are online and you +would use let's see in principle you + + align:start position:0% +would use let's see in principle you + + + align:start position:0% +would use let's see in principle you +could use any of the languages + + align:start position:0% +could use any of the languages + + + align:start position:0% +could use any of the languages +MATLAB Python which has become the + + align:start position:0% +MATLAB Python which has become the + + + align:start position:0% +MATLAB Python which has become the +biggest most used for deep learning or + + align:start position:0% +biggest most used for deep learning or + + + align:start position:0% +biggest most used for deep learning or +Julia which is the hot + + align:start position:0% +Julia which is the hot + + + align:start position:0% +Julia which is the hot +new language and so last semester the + + align:start position:0% +new language and so last semester the + + + align:start position:0% +new language and so last semester the +problems oh so what happened last year + + align:start position:0% +problems oh so what happened last year + + + align:start position:0% +problems oh so what happened last year +well everything in this course is ode to + + align:start position:0% +well everything in this course is ode to + + + align:start position:0% +well everything in this course is ode to +a professor who visited from University + + align:start position:0% +a professor who visited from University + + + align:start position:0% +a professor who visited from University +of Michigan professor rah-rahs Rao + + align:start position:0% +of Michigan professor rah-rahs Rao + + + align:start position:0% +of Michigan professor rah-rahs Rao +who taught gave most of the lectures a + + align:start position:0% +who taught gave most of the lectures a + + + align:start position:0% +who taught gave most of the lectures a +year ago brought these homework problems + + align:start position:0% +year ago brought these homework problems + + + align:start position:0% +year ago brought these homework problems +online homework problems so that people + + align:start position:0% +online homework problems so that people + + + align:start position:0% +online homework problems so that people +brought laptops to class and we did + + align:start position:0% +brought laptops to class and we did + + + align:start position:0% +brought laptops to class and we did +things in class and so he had had and + + align:start position:0% +things in class and so he had had and + + + align:start position:0% +things in class and so he had had and +has very successful course in EE in + + align:start position:0% +has very successful course in EE in + + + align:start position:0% +has very successful course in EE in +Michigan and but he was a PhD from here + + align:start position:0% +Michigan and but he was a PhD from here + + + align:start position:0% +Michigan and but he was a PhD from here +and he came back on a sabbatical and he + + align:start position:0% +and he came back on a sabbatical and he + + + align:start position:0% +and he came back on a sabbatical and he +created this got us started and we + + align:start position:0% +created this got us started and we + + + align:start position:0% +created this got us started and we +really owe a lot to him + + align:start position:0% + + + + align:start position:0% + +also professor Adelman was involved with + + align:start position:0% +also professor Adelman was involved with + + + align:start position:0% +also professor Adelman was involved with +this course and you may be know that he + + align:start position:0% +this course and you may be know that he + + + align:start position:0% +this course and you may be know that he +created julia how many like know what + + align:start position:0% +created julia how many like know what + + + align:start position:0% +created julia how many like know what +julia is Oh wonderful + + align:start position:0% +julia is Oh wonderful + + + align:start position:0% +julia is Oh wonderful +that will make his day he tells me every + + align:start position:0% +that will make his day he tells me every + + + align:start position:0% +that will make his day he tells me every +time I see him Julia's good and I tell + + align:start position:0% +time I see him Julia's good and I tell + + + align:start position:0% +time I see him Julia's good and I tell +him I believe it ok anyway and it's + + align:start position:0% +him I believe it ok anyway and it's + + + align:start position:0% +him I believe it ok anyway and it's +become the professor Johnson in 1806 has + + align:start position:0% +become the professor Johnson in 1806 has + + + align:start position:0% +become the professor Johnson in 1806 has +used Julia and every semester Stephen + + align:start position:0% +used Julia and every semester Stephen + + + align:start position:0% +used Julia and every semester Stephen +Johnson gives in the first week a + + align:start position:0% +Johnson gives in the first week a + + + align:start position:0% +Johnson gives in the first week a +tutorial on Julia and so he's that's + + align:start position:0% +tutorial on Julia and so he's that's + + + align:start position:0% +tutorial on Julia and so he's that's +arranged and I promised to tell you + + align:start position:0% +arranged and I promised to tell you + + + align:start position:0% +arranged and I promised to tell you +where where when that is so I think if + + align:start position:0% +where where when that is so I think if + + + align:start position:0% +where where when that is so I think if +you don't know anything about Julia try + + align:start position:0% +you don't know anything about Julia try + + + align:start position:0% +you don't know anything about Julia try +to go it's in Stata it's on Friday at + + align:start position:0% +to go it's in Stata it's on Friday at + + + align:start position:0% +to go it's in Stata it's on Friday at +5:00 5:00 to 7:00 so Julia from + + align:start position:0% +5:00 5:00 to 7:00 so Julia from + + + align:start position:0% +5:00 5:00 to 7:00 so Julia from +professor Johnson + + align:start position:0% +professor Johnson + + + align:start position:0% +professor Johnson +so he's done this multiple times he's + + align:start position:0% +so he's done this multiple times he's + + + align:start position:0% +so he's done this multiple times he's +good at it + + align:start position:0% +good at it + + + align:start position:0% +good at it +so that's McQueen Oh yet what I I guess + + align:start position:0% +so that's McQueen Oh yet what I I guess + + + align:start position:0% +so that's McQueen Oh yet what I I guess +I'm hoping that you'll have an option to + + align:start position:0% +I'm hoping that you'll have an option to + + + align:start position:0% +I'm hoping that you'll have an option to +use all any of the three languages but + + align:start position:0% +use all any of the three languages but + + + align:start position:0% +use all any of the three languages but +the the the online thing that we give + + align:start position:0% +the the the online thing that we give + + + align:start position:0% +the the the online thing that we give +you was created in Julia so professor + + align:start position:0% +you was created in Julia so professor + + + align:start position:0% +you was created in Julia so professor +Rao had to learn Julia last spring and + + align:start position:0% +Rao had to learn Julia last spring and + + + align:start position:0% +Rao had to learn Julia last spring and +though their class did too and there was + + align:start position:0% +though their class did too and there was + + + align:start position:0% +though their class did too and there was +a certain amount of bitching about it + + align:start position:0% +a certain amount of bitching about it + + + align:start position:0% +a certain amount of bitching about it +but I think with maybe one exception who + + align:start position:0% +but I think with maybe one exception who + + + align:start position:0% +but I think with maybe one exception who +still got an A we everybody was kind of + + align:start position:0% +still got an A we everybody was kind of + + + align:start position:0% +still got an A we everybody was kind of +okay and was glad to learn Julia and + + align:start position:0% +okay and was glad to learn Julia and + + + align:start position:0% +okay and was glad to learn Julia and +professor Rao now uses Julia entirely + + align:start position:0% +professor Rao now uses Julia entirely + + + align:start position:0% +professor Rao now uses Julia entirely +like so he's creating a new on-ramp with + + align:start position:0% +like so he's creating a new on-ramp with + + + align:start position:0% +like so he's creating a new on-ramp with +Julia + + align:start position:0% +Julia + + + align:start position:0% +Julia +MATLAB by the way has just issued an + + align:start position:0% +MATLAB by the way has just issued an + + + align:start position:0% +MATLAB by the way has just issued an +on-ramp to deep learning that I'll tell + + align:start position:0% +on-ramp to deep learning that I'll tell + + + align:start position:0% +on-ramp to deep learning that I'll tell +you about and probably get a MATLAB + + align:start position:0% +you about and probably get a MATLAB + + + align:start position:0% +you about and probably get a MATLAB +somebody from math works to to say + + align:start position:0% +somebody from math works to to say + + + align:start position:0% +somebody from math works to to say +something about it yeah so that's what's + + align:start position:0% +something about it yeah so that's what's + + + align:start position:0% +something about it yeah so that's what's +coming that we don't quite know exactly + + align:start position:0% +coming that we don't quite know exactly + + + align:start position:0% +coming that we don't quite know exactly +how we'll organize those homeworks would + + align:start position:0% +how we'll organize those homeworks would + + + align:start position:0% +how we'll organize those homeworks would +just take the first one and see see what + + align:start position:0% +just take the first one and see see what + + + align:start position:0% +just take the first one and see see what +happens + + align:start position:0% +happens + + + align:start position:0% +happens +so I'll certainly say more about + + align:start position:0% +so I'll certainly say more about + + + align:start position:0% +so I'll certainly say more about +homeworks when when the maybe even + + align:start position:0% +homeworks when when the maybe even + + + align:start position:0% +homeworks when when the maybe even +Friday but are there other questions + + align:start position:0% +Friday but are there other questions + + + align:start position:0% +Friday but are there other questions +that I should answer so because some + + align:start position:0% +that I should answer so because some + + + align:start position:0% +that I should answer so because some +people will be thinking okay am I going + + align:start position:0% +people will be thinking okay am I going + + + align:start position:0% +people will be thinking okay am I going +to do this or am I gonna sit in six oh + + align:start position:0% +to do this or am I gonna sit in six oh + + + align:start position:0% +to do this or am I gonna sit in six oh +three six or some other course in deep + + align:start position:0% +three six or some other course in deep + + + align:start position:0% +three six or some other course in deep +learning anything on your mind and you + + align:start position:0% +learning anything on your mind and you + + + align:start position:0% +learning anything on your mind and you +can email me so we will have a stellar + + align:start position:0% +can email me so we will have a stellar + + + align:start position:0% +can email me so we will have a stellar +site and you'll see all the the TAS are + + align:start position:0% +site and you'll see all the the TAS are + + + align:start position:0% +site and you'll see all the the TAS are +still to be named but the wonderful + + align:start position:0% +still to be named but the wonderful + + + align:start position:0% +still to be named but the wonderful +thing is that undergraduates who took + + align:start position:0% +thing is that undergraduates who took + + + align:start position:0% +thing is that undergraduates who took +this course last year are volunteering + + align:start position:0% +this course last year are volunteering + + + align:start position:0% +this course last year are volunteering +to be graders for you guys so they will + + align:start position:0% +to be graders for you guys so they will + + + align:start position:0% +to be graders for you guys so they will +know what those online homeworks were + + align:start position:0% +know what those online homeworks were + + + align:start position:0% +know what those online homeworks were +about it okay so that's what's it's a + + align:start position:0% +about it okay so that's what's it's a + + + align:start position:0% +about it okay so that's what's it's a +sort of first word about what's coming + + align:start position:0% +sort of first word about what's coming + + + align:start position:0% +sort of first word about what's coming +about about the language okay + + align:start position:0% +about about the language okay + + + align:start position:0% +about about the language okay +I'm gonna finish by a very important + + align:start position:0% +I'm gonna finish by a very important + + + align:start position:0% +I'm gonna finish by a very important +topic multiplying a times B oh look + + align:start position:0% +topic multiplying a times B oh look + + + align:start position:0% +topic multiplying a times B oh look +cleaning board so I know I want multiply + + align:start position:0% +cleaning board so I know I want multiply + + + align:start position:0% +cleaning board so I know I want multiply +multiply a matrix by a vector + + align:start position:0% +multiply a matrix by a vector + + + align:start position:0% +multiply a matrix by a vector +okay everybody knows how to do it you + + align:start position:0% +okay everybody knows how to do it you + + + align:start position:0% +okay everybody knows how to do it you +take a row of a so you take a row of a + + align:start position:0% +take a row of a so you take a row of a + + + align:start position:0% +take a row of a so you take a row of a +and you take a column of B and you take + + align:start position:0% +and you take a column of B and you take + + + align:start position:0% +and you take a column of B and you take +that dot product so you get dot product + + align:start position:0% +that dot product so you get dot product + + + align:start position:0% +that dot product so you get dot product +row row got column row dot that's again + + align:start position:0% +row row got column row dot that's again + + + align:start position:0% +row row got column row dot that's again +low level like okay for beginners but we + + align:start position:0% +low level like okay for beginners but we + + + align:start position:0% +low level like okay for beginners but we +want to see that matrix multiplication a + + align:start position:0% +want to see that matrix multiplication a + + + align:start position:0% +want to see that matrix multiplication a +B in a deeper way and the deeper way is + + align:start position:0% +B in a deeper way and the deeper way is + + + align:start position:0% +B in a deeper way and the deeper way is +columns times rows columns of a rows of + + align:start position:0% +columns times rows columns of a rows of + + + align:start position:0% +columns times rows columns of a rows of +B columns times rows well we had a + + align:start position:0% +B columns times rows well we had a + + + align:start position:0% +B columns times rows well we had a +column times a row right that was this + + align:start position:0% +column times a row right that was this + + + align:start position:0% +column times a row right that was this +rank one example we had our column times + + align:start position:0% +rank one example we had our column times + + + align:start position:0% +rank one example we had our column times +a row and it produced a matrix and + + align:start position:0% +a row and it produced a matrix and + + + align:start position:0% +a row and it produced a matrix and +that's what it looks like and it's rank + + align:start position:0% +that's what it looks like and it's rank + + + align:start position:0% +that's what it looks like and it's rank +was one so those are what + + align:start position:0% + + + + align:start position:0% + +we have a good so it's a combination of + + align:start position:0% + + + + align:start position:0% + +it's very like ax I'm really just + + align:start position:0% +it's very like ax I'm really just + + + align:start position:0% +it's very like ax I'm really just +extending the ax idea to a B so so this + + align:start position:0% +extending the ax idea to a B so so this + + + align:start position:0% +extending the ax idea to a B so so this +this is the old way a new way is columns + + align:start position:0% +this is the old way a new way is columns + + + align:start position:0% +this is the old way a new way is columns +so there's column K it will multiply + + align:start position:0% +so there's column K it will multiply + + + align:start position:0% +so there's column K it will multiply +sure enough it multiplies r okay + + align:start position:0% +sure enough it multiplies r okay + + + align:start position:0% +sure enough it multiplies r okay +everybody sees that it will happen that + + align:start position:0% +everybody sees that it will happen that + + + align:start position:0% +everybody sees that it will happen that +way if you do it the old way when you do + + align:start position:0% +way if you do it the old way when you do + + + align:start position:0% +way if you do it the old way when you do +a dot product of something here + + align:start position:0% +a dot product of something here + + + align:start position:0% +a dot product of something here +something here you're doing these + + align:start position:0% +something here you're doing these + + + align:start position:0% +something here you're doing these +multiplications and when you hit column + + align:start position:0% +multiplications and when you hit column + + + align:start position:0% +multiplications and when you hit column +K here you hit row K there so so these + + align:start position:0% +K here you hit row K there so so these + + + align:start position:0% +K here you hit row K there so so these +are connected so so I get things like + + align:start position:0% +are connected so so I get things like + + + align:start position:0% +are connected so so I get things like +column K of a times R okay of B and I + + align:start position:0% +column K of a times R okay of B and I + + + align:start position:0% +column K of a times R okay of B and I +don't know what notation to you so I + + align:start position:0% +don't know what notation to you so I + + + align:start position:0% +don't know what notation to you so I +just wrote them wrote the words okay + + align:start position:0% +just wrote them wrote the words okay + + + align:start position:0% +just wrote them wrote the words okay +but now that's one piece of the of the + + align:start position:0% +but now that's one piece of the of the + + + align:start position:0% +but now that's one piece of the of the +fun of the final answer a B that's a + + align:start position:0% +fun of the final answer a B that's a + + + align:start position:0% +fun of the final answer a B that's a +rank one piece that's a like a building + + align:start position:0% +rank one piece that's a like a building + + + align:start position:0% +rank one piece that's a like a building +block so I add from k equal 1 tom 1 + + align:start position:0% +block so I add from k equal 1 tom 1 + + + align:start position:0% +block so I add from k equal 1 tom 1 +times Row one column one of a times Row + + align:start position:0% +times Row one column one of a times Row + + + align:start position:0% +times Row one column one of a times Row +one of B plus da plus column K plus and + + align:start position:0% +one of B plus da plus column K plus and + + + align:start position:0% +one of B plus da plus column K plus and +of course I stop it column in of a times + + align:start position:0% +of course I stop it column in of a times + + + align:start position:0% +of course I stop it column in of a times +row in so it's a sum of outer products + + align:start position:0% +row in so it's a sum of outer products + + + align:start position:0% +row in so it's a sum of outer products +some of so everybody sees a sum because + + align:start position:0% +some of so everybody sees a sum because + + + align:start position:0% +some of so everybody sees a sum because +I I have column 1 times Row 1 column K + + align:start position:0% +I I have column 1 times Row 1 column K + + + align:start position:0% +I I have column 1 times Row 1 column K +times R ok call them n times row in and + + align:start position:0% +times R ok call them n times row in and + + + align:start position:0% +times R ok call them n times row in and +then I add those pieces it's just the + + align:start position:0% +then I add those pieces it's just the + + + align:start position:0% +then I add those pieces it's just the +generalization of a X 2 matrix B there + + align:start position:0% +generalization of a X 2 matrix B there + + + align:start position:0% +generalization of a X 2 matrix B there +so it's the sum of + + align:start position:0% + + + + align:start position:0% + +m'kay rogue of a Roque of B and maybe we + + align:start position:0% +m'kay rogue of a Roque of B and maybe we + + + align:start position:0% +m'kay rogue of a Roque of B and maybe we +should we check that that gives us the + + align:start position:0% +should we check that that gives us the + + + align:start position:0% +should we check that that gives us the +right answer or maybe I won't do that + + align:start position:0% +right answer or maybe I won't do that + + + align:start position:0% +right answer or maybe I won't do that +here but it it's it's all we're doing is + + align:start position:0% +here but it it's it's all we're doing is + + + align:start position:0% +here but it it's it's all we're doing is +the same multiplications in a different + + align:start position:0% +the same multiplications in a different + + + align:start position:0% +the same multiplications in a different +order actually let's just quit with one + + align:start position:0% +order actually let's just quit with one + + + align:start position:0% +order actually let's just quit with one +minute we can figure out how many + + align:start position:0% +minute we can figure out how many + + + align:start position:0% +minute we can figure out how many +multiplications are there how many + + align:start position:0% +multiplications are there how many + + + align:start position:0% +multiplications are there how many +multiplications to do a M by n matrix a + + align:start position:0% +multiplications to do a M by n matrix a + + + align:start position:0% +multiplications to do a M by n matrix a +time's the end by P matrix B so that's a + + align:start position:0% +time's the end by P matrix B so that's a + + + align:start position:0% +time's the end by P matrix B so that's a +times B how many individual numbers + + align:start position:0% +times B how many individual numbers + + + align:start position:0% +times B how many individual numbers +because this is determine the cost of it + + align:start position:0% +because this is determine the cost of it + + + align:start position:0% +because this is determine the cost of it +how many numbers would we need well + + align:start position:0% +how many numbers would we need well + + + align:start position:0% +how many numbers would we need well +suppose we do it the old way by in inner + + align:start position:0% +suppose we do it the old way by in inner + + + align:start position:0% +suppose we do it the old way by in inner +product row x column so how many how + + align:start position:0% +product row x column so how many how + + + align:start position:0% +product row x column so how many how +many multiplications to do a row times I + + align:start position:0% +many multiplications to do a row times I + + + align:start position:0% +many multiplications to do a row times I +call them and get one entry in the + + align:start position:0% +call them and get one entry in the + + + align:start position:0% +call them and get one entry in the +answer n right the row has length in the + + align:start position:0% +answer n right the row has length in the + + + align:start position:0% +answer n right the row has length in the +column has length in n multiplications + + align:start position:0% +column has length in n multiplications + + + align:start position:0% +column has length in n multiplications +so that's N and now how many of those do + + align:start position:0% +so that's N and now how many of those do + + + align:start position:0% +so that's N and now how many of those do +I have to do MP because what's the size + + align:start position:0% +I have to do MP because what's the size + + + align:start position:0% +I have to do MP because what's the size +of this answer the size of this answer + + align:start position:0% +of this answer the size of this answer + + + align:start position:0% +of this answer the size of this answer +is n by P okay so if I do they do it in + + align:start position:0% +is n by P okay so if I do they do it in + + + align:start position:0% +is n by P okay so if I do they do it in +that old order like n multiplications to + + align:start position:0% +that old order like n multiplications to + + + align:start position:0% +that old order like n multiplications to +do a dot product and I've got this many + + align:start position:0% +do a dot product and I've got this many + + + align:start position:0% +do a dot product and I've got this many +dot products in the answer so I've got M + + align:start position:0% +dot products in the answer so I've got M + + + align:start position:0% +dot products in the answer so I've got M +and P multiple multiplies now suppose I + + align:start position:0% +and P multiple multiplies now suppose I + + + align:start position:0% +and P multiple multiplies now suppose I +do it this way + + align:start position:0% + + + + align:start position:0% + +how many multiplications to do one of + + align:start position:0% +how many multiplications to do one of + + + align:start position:0% +how many multiplications to do one of +those guys to multiply a column by a row + + align:start position:0% +those guys to multiply a column by a row + + + align:start position:0% +those guys to multiply a column by a row +to multiply a column by a row this this + + align:start position:0% +to multiply a column by a row this this + + + align:start position:0% +to multiply a column by a row this this +is an M by one and this is a 1 by P one + + align:start position:0% +is an M by one and this is a 1 by P one + + + align:start position:0% +is an M by one and this is a 1 by P one +column one row + + align:start position:0% +column one row + + + align:start position:0% +column one row +how many multiplications for that guy in + + align:start position:0% +how many multiplications for that guy in + + + align:start position:0% +how many multiplications for that guy in +P and how many of those ranked ones do I + + align:start position:0% +P and how many of those ranked ones do I + + + align:start position:0% +P and how many of those ranked ones do I +have to do you got it it's MP times in + + align:start position:0% +have to do you got it it's MP times in + + + align:start position:0% +have to do you got it it's MP times in +now it's the other way was was n times + + align:start position:0% +now it's the other way was was n times + + + align:start position:0% +now it's the other way was was n times +MP so it gives the same answer MN p + + align:start position:0% +MP so it gives the same answer MN p + + + align:start position:0% +MP so it gives the same answer MN p +mostly in fact they're exactly the same + + align:start position:0% +mostly in fact they're exactly the same + + + align:start position:0% +mostly in fact they're exactly the same +multiplications just a different order + + align:start position:0% +multiplications just a different order + + + align:start position:0% +multiplications just a different order +okay we're at 155 thanks for coming + + align:start position:0% +okay we're at 155 thanks for coming + + + align:start position:0% +okay we're at 155 thanks for coming +today I'll talk more about the class and + + align:start position:0% +today I'll talk more about the class and + + + align:start position:0% +today I'll talk more about the class and +about linear algebra on Friday thank you \ No newline at end of file diff --git a/ZBlHexE8m6A.txt b/ZBlHexE8m6A.txt new file mode 100644 index 0000000000000000000000000000000000000000..2c481974f0fdedaa601fa6cc902dd774c21b7dbd --- /dev/null +++ b/ZBlHexE8m6A.txt @@ -0,0 +1,1107 @@ +align:start position:0% + +let's review what we've done this week + + align:start position:0% +let's review what we've done this week + + + align:start position:0% +let's review what we've done this week +we've seen that the work done by a force + + align:start position:0% +we've seen that the work done by a force + + + align:start position:0% +we've seen that the work done by a force +along a trajectory from point A to point + + align:start position:0% +along a trajectory from point A to point + + + align:start position:0% +along a trajectory from point A to point +B can be written as the integral of the + + align:start position:0% +B can be written as the integral of the + + + align:start position:0% +B can be written as the integral of the +dot product of that force with the + + align:start position:0% +dot product of that force with the + + + align:start position:0% +dot product of that force with the +displacement going from point A to point + + align:start position:0% +displacement going from point A to point + + + align:start position:0% +displacement going from point A to point +B well we note that this integral in + + align:start position:0% +B well we note that this integral in + + + align:start position:0% +B well we note that this integral in +general must be evaluated over the + + align:start position:0% +general must be evaluated over the + + + align:start position:0% +general must be evaluated over the +particular path taken from point A to + + align:start position:0% +particular path taken from point A to + + + align:start position:0% +particular path taken from point A to +point B this is called a line integral + + align:start position:0% +point B this is called a line integral + + + align:start position:0% +point B this is called a line integral +or a path integral and again I want to + + align:start position:0% +or a path integral and again I want to + + + align:start position:0% +or a path integral and again I want to +emphasize the value of this integral + + align:start position:0% +emphasize the value of this integral + + + align:start position:0% +emphasize the value of this integral +depends in general on the path taken + + align:start position:0% +depends in general on the path taken + + + align:start position:0% +depends in general on the path taken +from point A to point B and you can + + align:start position:0% +from point A to point B and you can + + + align:start position:0% +from point A to point B and you can +understand that if you consider the fact + + align:start position:0% +understand that if you consider the fact + + + align:start position:0% +understand that if you consider the fact +that in general the force is a function + + align:start position:0% +that in general the force is a function + + + align:start position:0% +that in general the force is a function +of position and so if you go along + + align:start position:0% +of position and so if you go along + + + align:start position:0% +of position and so if you go along +different paths the dot product of the + + align:start position:0% +different paths the dot product of the + + + align:start position:0% +different paths the dot product of the +force with a particular path may be + + align:start position:0% +force with a particular path may be + + + align:start position:0% +force with a particular path may be +different even though you're going + + align:start position:0% +different even though you're going + + + align:start position:0% +different even though you're going +between the same end points now the + + align:start position:0% +between the same end points now the + + + align:start position:0% +between the same end points now the +reason that the work is a useful concept + + align:start position:0% +reason that the work is a useful concept + + + align:start position:0% +reason that the work is a useful concept +is that it allows us to understand how + + align:start position:0% +is that it allows us to understand how + + + align:start position:0% +is that it allows us to understand how +the kinetic energy of an object so the + + align:start position:0% +the kinetic energy of an object so the + + + align:start position:0% +the kinetic energy of an object so the +kinetic energy is one-half MV squared + + align:start position:0% +kinetic energy is one-half MV squared + + + align:start position:0% +kinetic energy is one-half MV squared +the work allows us to understand how the + + align:start position:0% +the work allows us to understand how the + + + align:start position:0% +the work allows us to understand how the +kinetic energy evolves under the action + + align:start position:0% +kinetic energy evolves under the action + + + align:start position:0% +kinetic energy evolves under the action +of the force and we see that through + + align:start position:0% +of the force and we see that through + + + align:start position:0% +of the force and we see that through +what's called the work kinetic energy + + align:start position:0% +what's called the work kinetic energy + + + align:start position:0% +what's called the work kinetic energy +theorem which states that the work done + + align:start position:0% +theorem which states that the work done + + + align:start position:0% +theorem which states that the work done +so again the integral of F dot d s from + + align:start position:0% +so again the integral of F dot d s from + + + align:start position:0% +so again the integral of F dot d s from +point A to point B evaluated along the + + align:start position:0% +point A to point B evaluated along the + + + align:start position:0% +point A to point B evaluated along the +specific path is equal to the change in + + align:start position:0% +specific path is equal to the change in + + + align:start position:0% +specific path is equal to the change in +the kinetic energy so that's one-half + + align:start position:0% +the kinetic energy so that's one-half + + + align:start position:0% +the kinetic energy so that's one-half +and the B squared since B is the final + + align:start position:0% +and the B squared since B is the final + + + align:start position:0% +and the B squared since B is the final +point minus one-half M VA squared where + + align:start position:0% +point minus one-half M VA squared where + + + align:start position:0% +point minus one-half M VA squared where +a is the initial point and this is equal + + align:start position:0% +a is the initial point and this is equal + + + align:start position:0% +a is the initial point and this is equal +to the change + + align:start position:0% + + + + align:start position:0% + +in the kinetic energy and we derived + + align:start position:0% +in the kinetic energy and we derived + + + align:start position:0% +in the kinetic energy and we derived +this theorem from Newton's second law F + + align:start position:0% +this theorem from Newton's second law F + + + align:start position:0% +this theorem from Newton's second law F +equals MA so this is essentially just a + + align:start position:0% +equals MA so this is essentially just a + + + align:start position:0% +equals MA so this is essentially just a +restatement of Newton's second law now + + align:start position:0% +restatement of Newton's second law now + + + align:start position:0% +restatement of Newton's second law now +two things to note about the work and + + align:start position:0% +two things to note about the work and + + + align:start position:0% +two things to note about the work and +this work integral the first is that the + + align:start position:0% +this work integral the first is that the + + + align:start position:0% +this work integral the first is that the +work integral when evaluated can it just + + align:start position:0% +work integral when evaluated can it just + + + align:start position:0% +work integral when evaluated can it just +gives a number right because the dot + + align:start position:0% +gives a number right because the dot + + + align:start position:0% +gives a number right because the dot +product is a scalar and that number can + + align:start position:0% +product is a scalar and that number can + + + align:start position:0% +product is a scalar and that number can +be either positive or negative or even + + align:start position:0% +be either positive or negative or even + + + align:start position:0% +be either positive or negative or even +zero depending upon whether the velocity + + align:start position:0% +zero depending upon whether the velocity + + + align:start position:0% +zero depending upon whether the velocity +increases decreases or stays the same + + align:start position:0% +increases decreases or stays the same + + + align:start position:0% +increases decreases or stays the same +under the action of the force as you go + + align:start position:0% +under the action of the force as you go + + + align:start position:0% +under the action of the force as you go +from point A to point B the second point + + align:start position:0% +from point A to point B the second point + + + align:start position:0% +from point A to point B the second point +to emphasize is that again this integral + + align:start position:0% +to emphasize is that again this integral + + + align:start position:0% +to emphasize is that again this integral +in general must be evaluated along the + + align:start position:0% +in general must be evaluated along the + + + align:start position:0% +in general must be evaluated along the +specific path taken from point A to + + align:start position:0% +specific path taken from point A to + + + align:start position:0% +specific path taken from point A to +point B which means that in order to + + align:start position:0% +point B which means that in order to + + + align:start position:0% +point B which means that in order to +evaluate the integral we need to know + + align:start position:0% +evaluate the integral we need to know + + + align:start position:0% +evaluate the integral we need to know +what that path is now if we have a + + align:start position:0% +what that path is now if we have a + + + align:start position:0% +what that path is now if we have a +situation where we don't know in advance + + align:start position:0% +situation where we don't know in advance + + + align:start position:0% +situation where we don't know in advance +what the path is then we can't evaluate + + align:start position:0% +what the path is then we can't evaluate + + + align:start position:0% +what the path is then we can't evaluate +the integral so in a way it might seem + + align:start position:0% +the integral so in a way it might seem + + + align:start position:0% +the integral so in a way it might seem +like a not very useful concept that we + + align:start position:0% +like a not very useful concept that we + + + align:start position:0% +like a not very useful concept that we +haven't really made progress because we + + align:start position:0% +haven't really made progress because we + + + align:start position:0% +haven't really made progress because we +need to know the answer about what the + + align:start position:0% +need to know the answer about what the + + + align:start position:0% +need to know the answer about what the +trajectory is before we can calculate + + align:start position:0% +trajectory is before we can calculate + + + align:start position:0% +trajectory is before we can calculate +the work done and it's not clear why + + align:start position:0% +the work done and it's not clear why + + + align:start position:0% +the work done and it's not clear why +that's useful however what I want to + + align:start position:0% +that's useful however what I want to + + + align:start position:0% +that's useful however what I want to +point out is that there are two special + + align:start position:0% +point out is that there are two special + + + align:start position:0% +point out is that there are two special +cases that are particularly useful + + align:start position:0% + + + + align:start position:0% + +the first special case is that of + + align:start position:0% +the first special case is that of + + + align:start position:0% +the first special case is that of +constrained motion sometimes we know in + + align:start position:0% +constrained motion sometimes we know in + + + align:start position:0% +constrained motion sometimes we know in +advance sometimes we know in advance + + align:start position:0% +advance sometimes we know in advance + + + align:start position:0% +advance sometimes we know in advance +what the path is going to be because + + align:start position:0% +what the path is going to be because + + + align:start position:0% +what the path is going to be because +it's because the motion is constrained + + align:start position:0% +it's because the motion is constrained + + + align:start position:0% +it's because the motion is constrained +we know that it's going to be moving + + align:start position:0% +we know that it's going to be moving + + + align:start position:0% +we know that it's going to be moving +along the other going to be moving along + + align:start position:0% +along the other going to be moving along + + + align:start position:0% +along the other going to be moving along +a circular path or along some particular + + align:start position:0% +a circular path or along some particular + + + align:start position:0% +a circular path or along some particular +track of some particular shape and as + + align:start position:0% +track of some particular shape and as + + + align:start position:0% +track of some particular shape and as +long as we can describe that trajectory + + align:start position:0% +long as we can describe that trajectory + + + align:start position:0% +long as we can describe that trajectory +we can evaluate our work integral along + + align:start position:0% +we can evaluate our work integral along + + + align:start position:0% +we can evaluate our work integral along +that trajectory so that's a case where + + align:start position:0% +that trajectory so that's a case where + + + align:start position:0% +that trajectory so that's a case where +even though the work is a path dependent + + align:start position:0% +even though the work is a path dependent + + + align:start position:0% +even though the work is a path dependent +integral we know the path and so we can + + align:start position:0% +integral we know the path and so we can + + + align:start position:0% +integral we know the path and so we can +evaluate the integral the second special + + align:start position:0% +evaluate the integral the second special + + + align:start position:0% +evaluate the integral the second special +case we've seen is that there is a + + align:start position:0% +case we've seen is that there is a + + + align:start position:0% +case we've seen is that there is a +special class of forces called + + align:start position:0% +special class of forces called + + + align:start position:0% +special class of forces called +conservative forces and conservative + + align:start position:0% +conservative forces and conservative + + + align:start position:0% +conservative forces and conservative +forces have the property that the work + + align:start position:0% +forces have the property that the work + + + align:start position:0% +forces have the property that the work +integral is independent of the path so + + align:start position:0% +integral is independent of the path so + + + align:start position:0% +integral is independent of the path so +for a work integral all that Matt sorry + + align:start position:0% +for a work integral all that Matt sorry + + + align:start position:0% +for a work integral all that Matt sorry +for for a conservative force the work + + align:start position:0% +for for a conservative force the work + + + align:start position:0% +for for a conservative force the work +integral only depends upon the endpoints + + align:start position:0% +integral only depends upon the endpoints + + + align:start position:0% +integral only depends upon the endpoints +a and B and not upon the path you take + + align:start position:0% +a and B and not upon the path you take + + + align:start position:0% +a and B and not upon the path you take +to get from A to B so for any path + + align:start position:0% +to get from A to B so for any path + + + align:start position:0% +to get from A to B so for any path +you'll always get the same value of the + + align:start position:0% +you'll always get the same value of the + + + align:start position:0% +you'll always get the same value of the +work integral if the force is + + align:start position:0% +work integral if the force is + + + align:start position:0% +work integral if the force is +conservative and so those are the two + + align:start position:0% +conservative and so those are the two + + + align:start position:0% +conservative and so those are the two +cases in which we can usefully apply + + align:start position:0% +cases in which we can usefully apply + + + align:start position:0% +cases in which we can usefully apply +work and the work-energy theorem now in + + align:start position:0% +work and the work-energy theorem now in + + + align:start position:0% +work and the work-energy theorem now in +general one might have a combination of + + align:start position:0% +general one might have a combination of + + + align:start position:0% +general one might have a combination of +conservative and non-conservative forces + + align:start position:0% +conservative and non-conservative forces + + + align:start position:0% +conservative and non-conservative forces +acting on a system and in that case we + + align:start position:0% +acting on a system and in that case we + + + align:start position:0% +acting on a system and in that case we +can actually write the work as + + align:start position:0% +can actually write the work as + + + align:start position:0% +can actually write the work as +consisting of two separate terms the + + align:start position:0% +consisting of two separate terms the + + + align:start position:0% +consisting of two separate terms the +work done by conservative forces what + + align:start position:0% +work done by conservative forces what + + + align:start position:0% +work done by conservative forces what +I'll write is w sze plus the work done + + align:start position:0% +I'll write is w sze plus the work done + + + align:start position:0% +I'll write is w sze plus the work done +by the non-conservative forces WNC and + + align:start position:0% +by the non-conservative forces WNC and + + + align:start position:0% +by the non-conservative forces WNC and +so the conservative work is just the + + align:start position:0% +so the conservative work is just the + + + align:start position:0% +so the conservative work is just the +work integral evaluated for the + + align:start position:0% +work integral evaluated for the + + + align:start position:0% +work integral evaluated for the +conservative forces + + align:start position:0% +conservative forces + + + align:start position:0% +conservative forces +so f c for conservative force dot d s + + align:start position:0% +so f c for conservative force dot d s + + + align:start position:0% +so f c for conservative force dot d s +going from a to b and because this force + + align:start position:0% +going from a to b and because this force + + + align:start position:0% +going from a to b and because this force +is conservative + + align:start position:0% +is conservative + + + align:start position:0% +is conservative +this integral is path independent let me + + align:start position:0% +this integral is path independent let me + + + align:start position:0% +this integral is path independent let me +emphasize that here this is a path + + align:start position:0% +emphasize that here this is a path + + + align:start position:0% +emphasize that here this is a path +independent integral it's not a line + + align:start position:0% +independent integral it's not a line + + + align:start position:0% +independent integral it's not a line +integral it only depends upon the + + align:start position:0% +integral it only depends upon the + + + align:start position:0% +integral it only depends upon the +endpoints because the force is + + align:start position:0% +endpoints because the force is + + + align:start position:0% +endpoints because the force is +conservative the second term is the non + + align:start position:0% +conservative the second term is the non + + + align:start position:0% +conservative the second term is the non +conservative work and that is the work + + align:start position:0% +conservative work and that is the work + + + align:start position:0% +conservative work and that is the work +done by the non-conservative force F sub + + align:start position:0% +done by the non-conservative force F sub + + + align:start position:0% +done by the non-conservative force F sub +n C dotted with D s between the same + + align:start position:0% +n C dotted with D s between the same + + + align:start position:0% +n C dotted with D s between the same +endpoints a and B but this integral does + + align:start position:0% +endpoints a and B but this integral does + + + align:start position:0% +endpoints a and B but this integral does +depend upon the specific path the path + + align:start position:0% +depend upon the specific path the path + + + align:start position:0% +depend upon the specific path the path +matters for this term because there the + + align:start position:0% +matters for this term because there the + + + align:start position:0% +matters for this term because there the +force is non conservative so in general + + align:start position:0% +force is non conservative so in general + + + align:start position:0% +force is non conservative so in general +you can compute the work by separating + + align:start position:0% +you can compute the work by separating + + + align:start position:0% +you can compute the work by separating +out the conservative force and the non + + align:start position:0% +out the conservative force and the non + + + align:start position:0% +out the conservative force and the non +conservative force acting on the system + + align:start position:0% +conservative force acting on the system + + + align:start position:0% +conservative force acting on the system +if both are acting if the force is only + + align:start position:0% +if both are acting if the force is only + + + align:start position:0% +if both are acting if the force is only +conservative then you only have to worry + + align:start position:0% +conservative then you only have to worry + + + align:start position:0% +conservative then you only have to worry +about the path independent integral + + align:start position:0% +about the path independent integral + + + align:start position:0% +about the path independent integral +which in general is much simpler to + + align:start position:0% +which in general is much simpler to + + + align:start position:0% +which in general is much simpler to +evaluate if the force is non + + align:start position:0% +evaluate if the force is non + + + align:start position:0% +evaluate if the force is non +conservative then you need to specify + + align:start position:0% +conservative then you need to specify + + + align:start position:0% +conservative then you need to specify +the path in order to evaluate the + + align:start position:0% +the path in order to evaluate the + + + align:start position:0% +the path in order to evaluate the +integral again a path dependent integral + + align:start position:0% +integral again a path dependent integral + + + align:start position:0% +integral again a path dependent integral +is often called a path integral or a + + align:start position:0% +is often called a path integral or a + + + align:start position:0% +is often called a path integral or a +line integral \ No newline at end of file diff --git a/ZTNip78TUvA.txt b/ZTNip78TUvA.txt new file mode 100644 index 0000000000000000000000000000000000000000..87f9a915e329f041607be3c5f1cb74ace1f11bf9 --- /dev/null +++ b/ZTNip78TUvA.txt @@ -0,0 +1,3054 @@ +The following +content is provided + +under a Creative +Commons license. + +Your support will help MIT +OpenCourseWare continue + +to offer high quality +educational resources for free. + +To make a donation or to +view additional materials + +from hundreds of MIT courses, +visit MIT OpenCourseWare + +at ocs.mit.edu. + +PROFESSOR: Today we +have plenty to do. + +We really begin +in all generality + +the addition of +angular momentum. + +But we will do it in the set +up of a physical problem. + +The problem of +computing the spin + +orbit interactions of +electrons with the nucleus. + +So this is a rather interesting +and complicated interaction. + +So we'll spend a +little time telling you + +about the physics +of this interaction. + +And then once the +physics is clear, + +it will become +more obvious why we + +have to do these mathematical +contortions of adding angular + +momentum in order to solve +this physical problem. + +So it's a sophisticated problem +that requires several steps. + +The first step is +something that is + +a result in perturbation theory. + +Feynman Hellman Theorem +of perturbation theory. + +And that's where we begin. + +So it's called Feynman +Hellman Theorem. + +It's a very simple result. + +Theorem. + +And we'll need it in +order to understand + +how a small perturbation +to the Hamiltonian + +changes the energy spectrum. + +So we have H of lambda be a +Hamiltonian with a parameter + +in lambda. + +Lambda. + +And psi n of lambda +being normalized energy + +eigenstate with +energy, En of lambda. + +So that's the whole +assumption of the theorem. + +We have a Hamiltonian. + +It depends on some parameter +that we're going to vary. + +And suppose we consider now an +eigenstate of this Hamiltonian + +that depends on lambda, +so the eigenstate also + +depends on lambda. + +And it has an +energy, En of lambda. + +So the purpose of +this theorem is + +to relate these +various quantities. + +And the claim is that +the rate of change + +of the energy with +respect to lambda + +can be computed pretty much by +evaluating the rate of change + +of the Hamiltonian on +the relevant states. + +So that's the claim. + +And it's a pretty nice result. + +It's useful in +many circumstances. + +And for us will be a way to +discuss a little perturbation + +theory. + +Perturbation theory is the +subject of 806 in all details. + +And it's a very +sophisticated subject. + +Even today we were going +to be finding that it's not + +all that easy to carry it out. + +So how does this begin? + +Well, proof. + +You begin by saying +that En of lambda + +is the energy eigenstate, +is nothing else + +but psi n of lambda. + +H of lambda. + +Psi n of lambda. + +And the reason is, of +course, that H and psi n + +is En of lambda times +psi n of lambda. + +And this is a number goes out. + +And the inner product +of this things + +is 1, because the +state is normalized. + +So this is a good +starting point. + +And the funny thing that you see +already is that, in some sense, + +you just get the +middle term when + +you take the derivative +with respect to lambda. + +You don't get anything +from these two. + +And it's simple in fact. + +So let me just do it. + +V, En, V lambda +would be the term + +that Feynman and Hellman gave. + +V, H, V lambda, psi n of lambda. + +Plus one term in which we +differentiate this one. + +V, d lambda of the +state psi n of lambda. + +Times H of lambda, +psi n of lambda. + +Plus the other term in which +you differentiate the ket. + +So psi n of lambda, H of lambda, +d, d lambda of psi n of lambda. + +And the reason these +terms are going to vanish + +is that you can now act +with H again on psi n. + +H is supposed to be Hermitian, +so it can act on the left. + +And therefore, these two +terms give you En of lambda, + +times d d lambda of psi n of +lambda-- psi n of lambda-- + +plus the other term, which +would be psi n of lambda, + +the bra times the +derivative of the ket. + +But this is nothing +else than the derivative + +of the inner product. + +In the inner product +to differentiate-- + +the inner product +differentiates the bra, + +it differentiates the ket. + +And do it. + +And this thing is equal to +1, because it's normalized. + +So this is 0. + +End of proof. + +These two terms vanish. + +And the result holds. + +Yes? + +AUDIENCE: How do you +know it stays normalized + +when you vary lambda? + +PROFESSOR: It's an assumption. + +The state is normalized +for all values of n. + +So if you have a state +that you've constructed, + +that is normalized, you +can have this result. + +So it's an assumption. + +You have to keep the +state normalized. + +Now this is a baby version +of perturbation theory. + +It's a result I think that +Feynman did as an undergrad. + +And as you can see, +it's very simple. + +Calling it a theorem +is a little too much. + +But still, the fact +is that it's useful. + +And so we'll just +go ahead and use it. + +Now I want to rewrite +it in another way. + +So, suppose you have +a Hamiltonian, H, + +which has a term +H0, plus lambda, H1. + +So, the parameter lambda, H of +lambda, is given in this way. + +And that's a +reasonable H of lambda. + +Sometimes, this could be +written as H0 plus something + +that we will call the +change in the Hamiltonian. + +And we usually think +of it as a small thing. + +So what do we have +from this theorem? + +From this here we would +have the d, En, d lambda + +is equal to psi n of +lambda, H1, psi n of lambda. + +Now, we can be +particularly interested + +in the evaluation of this +thing at lambda equals 0. + +So what is d En of lambda? + +d lambda at lambda equals +0 would be psi n at zero, + +H1, psi n at 0. + +And therefore, you would say +that the En of lambda energies + +would be the energies +at 0, plus lambda, d En + +of lambda, d lambda +at lambda equals 0, + +plus order lambda squared. + +I'm doing just the +Taylor expansion + +of En's of lambda +from lambda equals 0. + +So this thing tells you that +En of lambda is equal En of 0, + +plus-- this derivative you can +write it as psi n, lambda, H1, + +psi n, all at 0. + +Like that. + +Plus order lambda squared. + +So in this step, I just use the +evaluation that we did here. + +I substituted that +and put the lambda in. + +So that I recognize now that En +of lambda is equal to En of 0, + +plus psi n of 0-- and I can +write this as delta H-- psi + +n of 0, plus order +delta H squared. + +It's nice to write it this +way, because you appreciate + +more the power of the theorem. + +The theorem here doesn't assume +which value of lambda you have. + +And you have to have +normalized eigenstates. + +And you wonder what is +it helping you with, + +if finding the states for every +value of lambda is complicated. + +Well, it certainly +helps you to figure out + +how the energy of the state +varies by a simple calculation. + +Suppose you know the states +of the simple Hamiltonian. + +Those are the psi's, n, 0. + +So if you have the +psi n 0 over here, + +you can do the following step. + +If you want to figure out +how it's energy has varied, + +use this formula in which +you compute the expectation + +value of the change in the +Hamiltonian on that state. + +And that is the first correction +to the energy of the state. + +So you have this state. + +You compute the +expectation value + +of the extra piece +in the Hamiltonian. + +And that's the +correction to the energy. + +It's a little more +complicated of course + +to compute the +correction to the state. + +But that's a subject +of perturbation theory. + +And that's not what we +care about right now. + +So the reason we're doing this +is because actually whatever + +we're going to have +with spin orbit coupling + +represents an addition +to the hydrogen + +Hamiltonian of a new term. + +Therefore, you want to know what +happens to the energy levels. + +And the best thing +to think about them + +is to-- if you know the +energy levels of this one, + +well, a formula of +this type can let + +you know what happens +to the energy levels + +after the perturbation. + +There will be an +extra complication + +in that the energy levels +that we're going to deal with + +are going to be degenerate. + +But let's wait for that +complication until it appears. + +So any questions? + +Yes? + +AUDIENCE: So I would +imagine that this + +would work just +as well for time. + +Because time [INAUDIBLE] a +parameter in quantum mechanics. + +So [INAUDIBLE] + +PROFESSOR: Time dependent +perturbation theory + +is a bit more complicated. + +I'd rather not get into it now. + +So let's leave it here, in +which we don't have time. + +And the Schrodinger +equation is something + +like H psi equal [INAUDIBLE] +psi, that's all we care. + +And leave it for that moment. + +Other questions? + +OK. + +So let's proceed with +addition of angular momentum. + +So first, let me give you +the fundamental result + +of addition of angular momentum. + +It's a little abstract, +but it's what we really + +mean by addition of +angular momentum. + +Of angular momentum. + +And the main result +is the following. + +Suppose you have a set +of operators, J, i, + +1, that have the algebra +of angular momentum. + +Of angular momentum. + +Which is to say +Ji1, JJ1, is equal + +i, h bar, epsilon iJK, JK1. + +And this algebra is realized +on some state space. + +On some vector space, V1. + +And suppose you have +another operator, + +J-- set of operators actually. + +Ji2, which have the algebra +of angular momentum. + +I will not write that. + +On some V2. + +OK. + +Angular momentum, +some sets of states. + +Angular momentum on some +other set of states. + +Here comes the thing. + +There is a new angular +momentum, which + +is the sum Ji defined +as Ji1, added with Ji2. + +Now, soon enough you will +just write Ji1, plus Ji2. + +But let me be a little +more careful now. + +This sum is Ji1, +plus 1, tensor Ji2. + +So i is the same index. + +But here, we're +having this operator + +that we're being defined +that we call it the sum. + +Now how do you sum two operators +that act in different spaces? + +Well, the only thing +that you can actually do + +is sum them in the +tensor product. + +So the claim is that this is an +angular momentum in V1 tensor + +V2. + +That is an operator. + +You see, you have to sum them. + +So you have to create a +space where both can act, + +and you can sum them. + +You cannot sum a thing, an +operator that acts on one + +vector space to an operator that +acts on another vector space. + +You have to create one +vector space where both act. + +And then you can define +the sum of the operators. + +Sum of operators +is a simple thing. + +So you form the tensor product. + +In here, this +operator gets upgraded + +in this way, in which in the +tensor product it has a 1 + +for the second input. + +This one gets +upgrade to this way. + +And this is the sum. + +So this is a claim-- +this is a definition. + +And this is a claim. + +So this has to be proven. + +So let me prove it. + +Ji, JJ. + +I compute this commutator. + +So I don't have to +do the following. + +I have to do Ji1, tensor +1, plus 1 tensor Ji2. + +And then the JJ would be JJ1, +tensor 1, plus 1, tensor JJ2. + +Have to compute this commutator. + +Now, an important +fact about this + +result that I'm not +trying to generalize, + +if you had put a minus +here, it wouldn't work out. + +If you would have put a 2 +here, it wouldn't work out. + +If you would have put a 1/2 +here, it won't work out. + +This is pretty much +the only way you + +can have two angular momenta, +and create a third angular + +momentum. + +So look at this. + +It looks like we're going +to have to work hard, + +but that's not true. + +Consider this commutator. + +The commutator of this +term with this term. + +That's 0 actually. + +Because if you multiply them +in this order, this times that, + +you get Ji1 times Ji2, +because the ones do nothing. + +You multiply them in +the reverse order, + +you get again, Ji1 times Ji2. + +This is to say that the +operators that originally lived + +in the different +vector spaces commute. + +Yes? + +AUDIENCE: Since the cross +terms between those two + +are 0-- like you just said, +the cross terms are 0. + +And if you put a minus sign +in there, it will cancel. + +But when you do +the multiplications + +with the second ones, why can't +you put a minus sign in there? + +[INAUDIBLE] + +PROFESSOR: In the whole thing? + +In this definition, +a minus sign? + +AUDIENCE: Yeah. + +PROFESSOR: Well, here +if I put a minus-- + +it's like I'm going to +prove that this works. + +So if-- I'm going to +get an angular momentum. + +If I put a minus sign +to angular momentum, + +I ruin the algebra here. + +I put a minus minus, it cancels. + +But then I get a +minus sign here. + +So I cannot really +even change a sign. + +So any way, these are operators +acting on different spaces. + +They commute. + +It's clear they commute. + +You just multiply +them, and see that. + +These one's commute as well. + +The only ones that don't +commute are this with this. + +And that with that. + +So let me just write them. + +Ji1, tensor 1, +with JJ1, tensor 1. + +Plus this one, 1 tensor +Ji2, 1 tensor JJ2. + +OK, next step is to +realize that actually + +the 1 is a spectator here. + +Therefore, this +commutator is nothing + +but the commutator Ji1 +with JJ1, tensor 1. + +You can do it. + +If you prefer to +write it, write it. + +This product is Ji +times JJ, tensor 1. + +And the other product +is JJ, Ji, tensor 1. + +So the tensor 1 factors out. + +Here the tensor 1 +also factors out. + +And you get an honest +commutator, Ji2, JJ2. + +So one last step. + +This is i, h bar, epsilon, iJK. + +I'll put a big parentheses. + +JK1, tensor 1, +for the first one. + +Because J1 forms an +angular momentum algebra. + +And here, 1 tensor JK2. + +And this thing is i, +h bar, epsilon, iJK. + +The total angular +momentum, K. And you've + +shown the algebra works out. + +Now most people after +a little practice, + +they just say, oh, Ji is +J1 plus J2, J1 plus J2. + +J1 and J2 don't commute. + +J2 and J1-- I'm sorry. + +J1 and J2 commute. + +J2 and J1 commute. + +Therefore you get +this 2, like that. + +And this gives you-- +J1 and J1 gives you J1. + +J2 and J2 gives you J2, +so the sum works out. + +So most people after +a little practice + +just don't put all +these tensor things. + +But at the beginning it's +nice to just make sure + +that you understand what +these tensor things do. + +All right. + +So that's our main +theorem-- that you + +start with one angular +momentum on a state space. + +Another angular momentum that +has nothing to do perhaps + +with the first on +another vector space. + +And on the tensor product you +have another angular momentum, + +which is the sum. + +All right. + +So now, we do spin +orbit coupling + +to try to apply these ideas. + +So for spin orbit coupling, we +will consider the hydrogen atom + +coupling. + +And the new term in the +Hamiltonian, mu dot B. + +The kind of term that we've +done so much in this semester. + +We've looked over magnetic ones. + +So which magnetic +moment at which B? + +There was no B in +the hydrogen atom. + +Well, there's no +B to begin with. + +But here is one where you can +think there is a B. First, + +this will be the +electron dipole moment. + +Magnetic dipole moment. + +So we have a formula for it. + +The formula for it is the mu of +the electron is minus E over m, + +times the spin of the electron. + +And I actually will use a +little different formula + +that is valued in +Gaussian units. + +ge over mC, S, in +Gaussian units. + +And g is the g factor of +the electron, which is 2. + +I'm sorry. + +There's a 2 here. + +OK. + +So look what I've written. + +I don't want to distract +you with this too much. + +But you know that the magnetic +dipole of the electron + +is given by this quantity. + +Now, you could put a +2 up, and a 2 down. + +And that's why people +actually classically + +there seems to be a 2 down. + +But there's a 2 up, because +it's an effect of the electron. + +And you have this formula. + +The only thing I've +added in that formula + +is a factor of C that is +because of Gaussian units. + +And it allows you to estimate +terms a little more easily. + +So that's the mu +of the electron. + +But the electron apparently +would feel no magnetic field. + +You didn't put an +external magnetic field. + +Except that here +you go in this way + +of thinking-- you think +suppose you are the electron. + +You see a proton, which is +a nucleus going around you. + +And a proton going around you +is a current going around you. + +It generates a magnetic field. + +And therefore, you +see a magnetic field + +created by the proton +going around you. + +So there is a magnetic field. + +And there's a magnetic +field experienced + +by the electron-- +felt by electron. + +So you can think of +this, the electron. + +Here is the proton +with the plus charge, + +and here's the electron. + +And the electron is +going around the proton. + +Now, from the viewpoint +of the electron, + +the proton is going around him. + +So here is the proton. + +Here is the electron +going like that. + +From the viewpoint +of the electron, + +the proton is going like this. + +Also, from the viewpoint +of the electron, + +the proton would be +going in this direction + +and creating a +magnetic field up. + +And the magnetic field +up corresponds actually + +to the idea that the angular +momentum of the electron + +is also up-- L of the +electron is also up. + +So the whole point +of this thing is + +that somehow this magnetic field +is proportional to the angular + +momentum. + +And then, L will come here. + +And here, you have +S. So you have + +L dot S. That's the +fine structure coupling. + +Now let me do a little +of this so that we just + +get a bit more feeling, +although it's unfortunately + +a somewhat frustrating exercise. + +So let me tell you +what's going on. + +So consider the electron. + +At some point, look at +it and draw a plane. + +So the electron-- let's +assume it's going down. + +Here is the proton. + +It's going around in circles. + +So here, it's going down. + +The electron is going down. + +Electron, its velocity of +the electron is going down. + +The proton is over here. + +And the electron is +going around like that. + +The proton would produce an +electric field of this form. + +Now, in relativity, the +electric and magnetic fields + +seen by different +observers are different. + +So there is this electric +field that we see. + +We sit here, and we +see in our rest frame + +this proton creates +an electric field. + +And then, from the +viewpoint of the electron, + +the electron is moving. + +And there is an electric field. + +But whenever you are moving +inside an electric field, + +you also see a magnetic field +generated by the motion, + +by relativistic effects. + +The magnetic field +that you see is roughly + +given to first order in +relativity by V cross E over c. + +So V cross E, VE +V cross E over c + +up-- change sign +because of this. + +And the magnetic +field consistently, + +as we would expect, +goes in this direction. + +So it's consistent +with the picture + +that we developed that if you +were the electron, the proton, + +would be going around +in circles like that + +and the magnetic +field would be up. + +Now here I can change the sign +by doing E cross V over c. + +So this is the magnetic +field seen by the electron. + +OK, so we need a little more +work on that magnetic field + +by calculating the +electric field. + +Now, what is the electric field? + +Well, the scalar potential +for the hydrogen atom, + +we write it as minus +e squared over r. + +It's actually not quite +the scalar potential. + +But it is the potential energy. + +It has one factor of e more than +what the scalar potential is. + +Remember, the scalar +potential in electromagnetism + +is charge divided by r. + +So it has one factor of e more. + +What is the derivative +of this potential? + +With respect to r, it's +e squared over r squared. + +So the electric field goes +like e over r squared. + +So the electric field is +equal to dV dr divided by e. + +That's the magnitude +of the electric field. + +And its direction is radial from +the viewpoint of the proton. + +The electric field is here. + +So this can be written +as r vector divided by r. + +Therefore, the magnetic field +will-- [INAUDIBLE] this. + +The magnetic field +now can be calculated. + +And we'll see what +we claimed was + +the relation with +angular momentum. + +Because B prime +is now E cross V. + +So you have 1 over +ec 1 over r dV dr. + +I've taken care of this. + +And now I just have +r cross V. Well, + +r cross V is your angular +momentum if you had p here. + +So we borrow a factor of +the mass of the electron, + +ecm 1 over r dV dr +L, L of the electron. + +p equals mv. + +So we have a nice formula +for B. And then, we + +can go and calculate delta +H. Delta H would then + +be minus mu dot B. And that +would be ge over 2mc spin + +dot L-- mu was given here-- +S dot L 1 over r dV dr. + +And that is the split +spin orbit interaction. + +Now, the downside +of this derivation + +is that it has a +relativistic error. + +There's a phenomenon +called Thomas precession + +that affects this result. + +We didn't waste our time. + +The true result is that you +must subtract from this g 1. + +So g must really be +replaced by g minus 1. + +Since g is approximately +2 for the electron, + +the true result is +really 1/2 of this thing. + +So this should not +be in parentheses, + +but true result is this. + +And the mistake that is done +in calculating this spin orbit + +coupling is that this +spin orbit coupling + +affects precession rates. + +All these interactions +of magnetic dipoles + +with magnetic fields +affect precession rates. + +And you have to be a +little more careful here + +that the system where you've +worked, the electron rest frame + +is not quite an inertial system. + +Because it's doing +circular motion. + +So there's an extra correction +that has to be done. + +Thomas precession or Thomas +correction it's called. + +And it would be a +detour of about one hour + +in special relativity +to do it right. + +So Griffiths doesn't do it. + +I don't think Shankar does it. + +Pretty much graduate +books do it. + +So we will not try to do better. + +I mentioned that +fact that this really + +should be reduced to +one half of its value. + +And it's an interesting +system to analyze. + +So Thomas precession is +that relativistic correction + +to precession rates when the +object that is precessing + +is in an accelerated frame. + +And any rotating +frame is accelerated. + +So this result needs correction. + +OK, but let's take this result +as it is-- instead of g, + +g minus 1. + +Let's not worry +too much about it. + +And let's just estimate +how big this effect is. + +It's the last thing I want +to do as a way of motivating + +this subject. + +So delta H is this. + +Let's estimate it. + +Now for estimates, a couple of +things are useful to remember, + +that Bohr radius is h +squared over me squared. + +We did that last time. + +And there's this constant +that is very useful, + +the fine structure constant, +which is e squared over hc. + +And it's about 1 over 137. + +And it helps you estimate +all kinds of things. + +Because it's a rather +complicated number to evaluate, + +you need all kinds of +units and things like that. + +So the charge of the electron +divided by hc being 1 over 137 + +is quite nice. + +So let's estimate +delta H. Well, g + +we won't worry-- 2, +1, doesn't matter. + +e mc-- so far, that +is kind of simple. + +Then we have S dot L. Well, +how do I estimate S dot L? + +I don't do too much. + +S spin is multiples of h bar. + +L for an atomic state will be +1, 2, 3, so multiples of h bar. + +So h bar squared, +that's it for S dot L. + +1 over r is 1 over r. + +dV dr is e squared +over r squared. + +And that's it. + +But here, instead of r, I +should put the typical length + +of the hydrogen +atom, which is a0. + +So what do I get? + +I'm sorry, I made +a mistake here. + +AUDIENCE: Yeah, it's up there. + +PROFESSOR: Oh, I +made a mistake here + +in that I didn't put +this factor, 1 over ecm. + +So the e cancels. + +And this is the result +here-- g over 2m + +squared c squared S dot L 1 over +r dV dr. So let me start again. + +1 over m squared c squared h +bar squared 1 over r dV dr-- + +that much I got right. + +So this is roughly +1 over [INAUDIBLE] + +of the electron +squared c squared e + +squared over a0 cubed +h squared-- still quite + +messy, but not that terrible. + +So in order to get an +idea of how big this is, + +the ground state energy +of the hydrogen atom + +was e squared over 2a0. + +So let's divide delta H over +the ground state energy. + +And that's how much? + +Well, we have all this +quantity, 1 over m + +squared c squared e +squared a0 cubed h squared. + +And now, we must divide by +e squared over a0 like this. + +Well, the e squareds cancel. + +And we get h squared over m +squared c squared a0 squared. + +You need to know what a0 is. + +Let's just boil it down +to the simplest thing, + +so h squared m +squared c squared. + +a0 squared would be h to +the fourth m squared e + +to the fourth. + +So this is actually e +to the fourth over h + +squared c squared, or e squared +over hc squared, which is alpha + +squared. + +Whew-- lots of work to +get something very nice. + +The ratio of the spin orbit +coupling to the ground state + +energy is 1 over alpha squared. + +It's alpha squared, which +is 1 over 137 squared. + +So it's a pretty small thing. + +It's about 1 over 19,000. + +So when this is called fine +structure of the hydrogen atom, + +it means that it's in +the level in your page + +that you use a few inches +to plot the 13.6 electron + +volts-- well, you're talking +about 20,000 times smaller, + +something that you don't see. + +But of course, it's a +pretty important thing. + +So all in all, in the +conventions of-- this + +is done in Gaussian units. + +In SI units, which is +what Griffiths uses, + +delta H is e squared over +8 pi epsilon 0 1 over m + +squared c squared r cubed S +dot L. That's for reference. + +This is Griffiths. + +But this is correct as well. + +This is the correct value. + +This is the correct +value already taking + +into account the +relativistic correction. + +So here, you're supposed +to let g go to g minus 1. + +So you can put the 1 there, +and it's pretty accurate. + +All right, so what is +the physics question + +we want to answer with +this spin orbit coupling? + +So here it comes. + +You have the hydrogen +atom spectrum. + +And that spectrum you know. + +At L equals 0, you +have one state here. + +Then, that's n +equals 1, n equals 2. + +You have one state here and +one state here at L equals 1. + +Then n equals 3, they start +getting very close together. + +n equals 4 is like that. + +Let's consider if you want +to have spin orbit coupling, + +we must have angular momentum. + +And that's L. And therefore, +let's consider this state here. + +l equals 1, n equals 1-- +n equals 2, I'm sorry. + +What happens to those +states, is the question. + +First, how many states +do you have there + +and how should +you think of them? + +Well actually, we know that +an l equals 1 corresponds + +to three states. + +So you'd have lm +with l equals 1. + +And then m can be +1, 0, or minus 1. + +So you have three states. + +But there's not +really three states. + +Because the electron +can have spin. + +So here it is, a tensor product +that appears in your face + +because there is +more than angular + +momentum to the electron. + +There's spin. + +And it's a totally different +vector space, the same particle + +but another vector +space, the spin space. + +So here, you have the possible +spins of the electron. + +So that's another +angular momentum. + +And well, you could have the +plus/minus states, for example. + +So you have three states +here and two states here. + +So this is really six +states, so six states + +whose fate we would +like to understand + +due to this spin orbit coupling. + +So to use the language +of angular momentum, + +instead of writing +plus/minus, you + +could write Smz, if you will-- +ms I will call, spin of s. + +You have here spin of 1/2 +and states 1/2 or minus 1/2. + +This is the up. + +When the z component of the spin +that we always call m-- m now + +corresponds to the z +component of angular momentum. + +So in general, even +for spin, we use m. + +And we have that our two +spin states of the electron + +are spin 1/2 particle with +plus spin in the z direction, + +spin 1/2 particle with minus +spin in the z direction. + +We usually never +put this 1/2 here. + +But now you have here +really three states-- + +1, 1, 1, 0, 1, minus 1, +the first telling you + +about the total +angular momentum. + +Here, the total spin is 1/2. + +But it happens to be +either up or down. + +Here, the total +angular momentum is 1. + +But it happens to be plus +1, 0, or minus 1 here. + +So these are our six states. + +You can combine this with this, +this with that, this with this, + +this with that. + +You make all the products. + +And these are the six +states of the hydrogen + +atom at this level. + +And we wish to know +what happens to them. + +Now, this correction is small. + +So it fits our understanding +of the perturbation theory + +of Feynman-Hellman +in which we try + +to find the corrections +to these things. + +Our difficulty now is a +little serious, however. + +It's the fact that +Feynman-Hellman + +assumed that you had a state. + +And it was an eigenstate of +the corrected Hamiltonian + +as you moved along. + +And then, you could compute +how its energy changes. + +Here, unfortunately, we have a +much more difficult situation. + +These six states that +I'm not listing yet, + +but I will list very soon, +are not obviously eigenstates + +of delta H. In fact, they are +not eigenstates of delta H. + +They're degenerate states, +six degenerate states, + +that are not eigenstates +of delta H. Therefore, + +I cannot use the Feynman-Hellman +theorem until I find what are + +the combinations that +are eigenstates of this + +perturbation. + +So we are a little +bit in trouble. + +Because we have a perturbation +for which these product + +states-- we call them uncoupled +bases-- are not eigenstates. + +Now, we've written this +operator a little naively. + +What does this operator +really mean, S dot L? + +In our tensor products, +it means S1 tensor L1. + +Actually, I'll use +L dot S. I'll always + +put the L information first and +the S information afterward. + +So L dot S is clearly +an operator that + +must be thought to act +on the tensor product. + +Because both have to act. + +S has to act and L has to act. + +So it only lives in +the tensor product. + +So what does it mean? + +It means this-- S2 L2 plus S3 +L3, or sum over i Si tensor Li. + +So this is the kind of thing +that you need to understand-- + +how do you find for this +operator's eigenstates here? + +So that is our difficulty. + +And that's what +we have to solve. + +We're going to solve it +in the next half hour. + +So it's a complicated operator, +L dot S. But on the other hand, + +we have to use our ideas +that we've learned already + +about summing angular momenta. + +What if I define +J to be L plus S, + +which really means L +tensor 1 plus 1 tensor S? + +So this is what I really +mean by this operator. + +J, as we've demonstrated, +will be an angular momentum, + +because this satisfies the +algebra of angular momentum + +and this satisfies the +algebra of angular momentum. + +So this thing satisfies the +algebra of angular momentum. + +And why do we look at that term? + +Because of the following reason. + +We can square it-- JiJi. + +Now we would have to +square this thing. + +How do you square this thing? + +Well, there's two ways. + +Naively-- L squared +plus L squared plus 2L + +dot S-- basically correct. + +But you can do it a +little more slowly. + +If you square this term, +you get L squared tensor 1. + +If you square this term, +you get 1 tensor S squared. + +But when you do +the mixed products, + +you just must take the +i's here and the i's here + +and multiply them. + +So actually, you do get two i's, +the sum over i Li tensor Si. + +This is sum over i. + +This is J squared. + +So basically, what I'm saying +is that J squared naively + +is L squared plus S squared +plus our interaction + +2L dot S defined property. + +So L dot S is equal to 1/2 +of J squared minus L squared + +minus S squared. + +And that tells you all kinds of +interesting things about L dot + +S. + +Basically, we can trade +L dot S for J squared, + +L squared, and S squared. + +L squared is very +simple, and S squared + +is extremely simple as well. + +Remember, L squared +commutes with any Li. + +So L squared with +any Li is equal to 0. + +S squared with any +Si is equal to 0. + +And Li's and Si's commute. + +They live in different worlds. + +So L squared and Si's commute. + +S squareds and Li's commute. + +These things are +pretty nice and simple. + +So let's think now +of our Hamiltonian + +and what is happening to it. + +Whenever we had +the hydrogen atom, + +we had a set of commuting +observables H, L squared, + +and Lz. + +It's a complete set of +commuting observables. + +Now, in the hydrogen +atom, you could add to it + +S squared and Sz. + +We didn't talk about +spin at the beginning, + +because we just considered +a particle going + +around the hydrogen atom. + +But if you have spin, the +hydrogen atom Hamiltonian, + +the original one, doesn't +involve spin in any way. + +So certainly, Hamiltonian +commutes with spin, + +with spin z. + +L and S don't talk, so +this is the complete set + +of commuting observables. + +But what happens to this list? + +This is our problem for +H0, the hydrogen atom, + +plus delta H that +has the S dot L. + +Well, what are complete set +of commuting observables? + +This is a very +important question. + +Because this is +what tells you how + +you're going to try to +organize the spectrum. + +So we could have H, +the total, H total. + +And what else? + +Well, can I still +have L squared here? + +Can I include L squared and say +it commutes with the total H? + +A little worrisome, +but actually, + +you know that L squared commutes +with the original Hamiltonian. + +Now, the question is +whether L squared commutes + +with this extra piece. + +Well, but L squared +commutes with any Li. + +And it doesn't even talk +to S. So L squared is safe. + +L squared we can keep. + +OK, S squared-- can +we keep S squared? + +Well, S squared was here. + +So it commuted with the +Hamiltonian, and that was good. + +S squared commutes with any +Si, and it doesn't talk to L. + +So S squared can stay. + +But that's not good enough. + +We won't be able to solve +the problem with this still. + +We need more. + +How about Lz? + +It was here, so +let's try our luck. + +Any opinions on Lz-- +can we keep it or not? + +Yes. + +AUDIENCE: I don't think so. + +Because in the J term, we +have Lx's and Ly's, which + +don't commute with Lz. + +PROFESSOR: Right, +it can't be kept. + +Here, this term has SxLx +plus SyLy plus SzLz. + +And Lz doesn't +commute with this one. + +So no, you can't +keep Lz-- no good. + +On the other hand, let's +think about J squared. + +J squared is here. + +And J squared commutes with +L squared and with S squared. + +J squared, therefore, is-- +well, let me say it this way. + +Here is L dot S, which +is our extra interaction. + +Here we have this thing. + +I would like to say +on behalf of J squared + +that we can include +it here, J squared, + +because J squared is +really pretty much the same + +as L dot S up to this L +squared and S squared. + +But J squared commutes with +L squared and S squared. + +I should probably +write it there. + +J squared commutes +with L squared. + +And J squared communicates with +S squared that we have here. + +And moreover, we have over +here that J squared therefore + +will commute, or it's +pretty much the same, + +as L dot S. J squared +with L dot S would + +be J squared times +this thing, which is 0. + +So J squared commutes +with this term. + +And it commutes with +the Hamiltonian, + +your original +hydrogen Hamiltonian. + +So J squared can be added here. + +J square is a good +operator to have. + +And now we can get one more +kind of free from here. + +It's Jz. + +Z + +Because Jz commutes +with J squared. + +Jz commutes with these things. + +And Jz, which is a symmetry +of the original Hamiltonian, + +also commutes with our new +interaction, the L dot S, + +which is proportional +to J squared. + +So you have to go +through this yourselves + +probably even a little +more slowly than I've gone. + +Just check that +everything that I'm + +saying about whatever +commutes commutes. + +So for example, when I say +that J squared commutes + +with L dot S, it's +because I can put + +instead of L dot S all of this. + +And go slowly through this. + +So this is actually the complete +set of committing observables. + +And it's basically +saying to us, try + +to diagonalize this thing +with total angular momentum. + +So it's about time +to really do it. + +We haven't done it yet. + +But now the part that +we have to do now, + +it's kind of a nice exercise. + +And it's fun. + +Now, there's one problem +in the homework set + +that sort of uses +this kind of thing. + +And I will suggest there to +Will and Aram that tomorrow, + +they spend some time discussing +it and helping you with it. + +The last problem +in the homework set + +would've been better if you +had a little more time for it + +and you had more time to +digest what I'm doing today. + +But nevertheless, +go to recitation, + +learn more about the problem. + +It will not be all +that difficult. + +OK, so we're trying +now to finally form + +another basis of states. + +We had these six states. + +And we're going to +try to organize them + +in a better way-- as eigenstates +of the total angular momentum L + +plus S. So I'm going to +write them here in this way. + +Here is one of the +states of this L equals + +1 electron, the 1, 1 +coupled to the 1/2, 1/2. + +Here are two more states- 1, 0, +1/2, 1/2, 1, 1, 1/2, minus 1/2, + +so the 1, 0 with the top, +the 1, 1 with the bottom. + +Here are two more +states-- 1, 0 with 1/2, + +minus 1/2 and 1, +minus 1 with 1/2, 1/2. + +And here is the last state-- +1, minus 1 with 1/2, minus 1. + +These are our six states. + +And I've organized them +in a nice way actually. + +I've organized +them in such a way + +that you can read what is +the value of Jz over h bar. + +Remember, Jz is 1 +over h bar Lz plus Sz. + +So what is it? + +These are, I claim, +eigenstates of Jz. + +Why? + +Because let's act on them. + +Suppose I act with +Jz on this state. + +The Lz comes here and says, 1. + +The Sz comes here and says, 1/2. + +So the sum of them give you +Jz over h bar equal to 3/2. + +And that's why I organized +these states in such a way + +that these second things add up +to the same value-- 0 and 1/2, + +1 and minus 1/2. + +So if you act with +Jz on this state, + +it's an eigenstate with Jz. + +Here, 0 contribution, here 1/2. + +So this is with plus 1/2. + +Here, you have 0 and minus 1/2, +minus 1, and that is minus 1/2. + +And here you have minus 3/2. + +OK, questions. + +We've written the states. + +And I'm evaluating the total z +component of angular momentum. + +And these two states +are like that. + +So what does our theorem +guarantee for us? + +Our theorem guarantees that we +have-- in this tensor product, + +there is an algebra of angular +momentum of the Jz operators. + +And the states have to +fall into representations + +of those operators. + +So you must have angular +momentum multiplets. + +So at this moment, +you can figure out + +what angular momentum you're +going to get for the result. + +Here we obtained a +maximum Jz of 3/2. + +So we must get a J +equals 3/2 multiplet. + +Because a J equaling +3/2 multiplets + +has Jz 3/2, 1/2, +minus 1/2, and 0. + +So actually, this state must be +the top state of the multiplet. + +This state must be the bottom +state of the multiplet. + +I don't know which one is the +middle state of the multiplet + +and which one is here. + +But we have four states +here, four states. + +So one linear combination +of these two states + +must be, then, that Jz equals +1/2 state of the multiplet. + +And one inner combination +of these two states + +must be that Jz equals minus +1/2 state of the multiplet. + +Which one is it? + +I don't know. + +But we can figure it out. + +We'll figure it out in a second. + +Once you get this +J 3/2 multiplet, + +there will be one linear +combination here left over + +and one linear combination +here left over. + +Those are two state, one with +Jz plus 1/2 and one with Jz + +equals minus 1/2. + +So you also get a J +equals 1/2 multiplet. + +So the whole tensor +product of six + +states-- it was the +tensor product of a spin 1 + +with a spin 1/2. + +So we write it like this. + +The tensor product of a +spin 1 with a spin 1/2 + +will give you a total +spin 3/2 plus total spin + +1/2-- funny formula. + +Here is the tensor +product, the tensor + +product of these three +states with these two states. + +This can be written as 3 +times 2 is equal to 4 plus 2 + +in terms of number of states. + +The tensor product of +this spin 1 and spin 1/2 + +gives you a spin 3/2 +multiplet with four states + +and a spin 1/2 multiplet +with two states. + +So how do you calculate what +are the states themselves? + +So the states themselves +are the following. + +All right, here I have them. + +I claim that the J +equals 3/2 states, + +m equals 3/2 states, the +top state of that multiplet + +can only be the state here, +the 1, 1 tensor 1/2, 1/2. + +And there's no way any other +state can be put on the right. + +Because there's no other +state with total z component + +of angular momentum equals 3/2. + +So that must be the state. + +Similarly, the J +equals 3/2, m equals + +minus 3/2 state must be the +bottom one-- 1, minus 1, 1/2, + +minus 1/2. + +The one that we +wish to figure out + +is the next state here, which is +the J equals 3/2, m equals 1/2. + +It's a linear +combination of these two. + +But which one? + +That is kind of the last +thing we want to do. + +Because it will pretty much +solve the rest of the problem. + +So how do we solve for this? + +Well, we had this +basic relation that we + +know how to lower or raise +states of angular momentum-- + +m times m plus/minus 1 J-- +I should have written it + +J plus/minus Jm equals +h bar square root. + +More space for everybody +to see this-- J times + +J plus 1 minus m +times m plus/minus 1. + +Close the square +root-- Jm plus/minus 1. + +So what I should try to +do is lower this state, + +try to find this state +by acting with J minus. + +So let me try to +lower the state, so + +J minus on this state, on +J equals 3/2, m equals 3/2. + +I can go to that formula and +write it as h bar square root. + +J is 3/2, so 3/2 times +5/2 minus m, which is 3/2, + +times m minus 1, 1/2. + +We're doing the minus-- +times the state 3/2, 1/2. + +So the state we want is here. + +And it's obtained by +doing J minus on that. + +But we want the number here. + +So that's why I did +all these square roots. + +And that just gives h bar +square root of 3, 3/2, 1/2. + +Well, that still doesn't +calculate it for me. + +But it comes very close. + +So you have it there. + +Now I want to do this but +using the right hand side. + +So look at the right hand side. + +We want to do J minus, but +on 1, 1 tensor 1/2, 1/2. + +So I applied J minus +to the left hand side. + +Now we have to apply J minus +to the right hand side. + +But J minus is L minus plus S +minus on 1, 1 tensor 1/2, 1/2. + +When this acts, it +acts on the first. + +So you get L minus on +1, 1 tensor 1/2, 1/2. + +And in the second term, +you get plus 1, 1 tensor S + +minus on 1/2, 1/2. + +Now, what is L minus on 1, 1? + +You can use the same formula. + +It's 1, 1. + +And it's an angular momentum. + +So it just goes on and +gives you h bar square + +root of 1 times 2 +minus 1 times 0. + +1, 0-- it lowers +it-- times 1/2, 1/2. + +Let me go here-- plus 1, 1. + +And what is S minus on this? + +Use the formula +with J equals 1/2. + +So this is h bar square root of +1/2 times 3/2 minus 1/2 times + +minus 1/2 times 1/2 minus 1/2. + +Whew-- well not too difficult. + +But this gives you h over square +root of 2, 1, 0 tensor 1/2, + +1/2 plus just h bar. + +This whole thing is 1-- 1, +1 tensor 1/2, minus 1/2. + +OK, stop a second to +see what's happened. + +We had this equality. + +And we acted with J minus. + +Acting on the left, +it gives us a number + +times the state we want. + +Acting on the +right, we got this. + +So actually, equating this +to that, or left hand side + +to right hand side, we finally +found the state 3/2, 1/2. + +So the state 3/2, +1/2 is as follows. + +3/2, 1/2 is-- you must +divide by that square root. + +So you get the square +root of 3 down. + +The h bars cancel. + +So here it is, a very nice +little formula-- 2 over 3, + +1, 0 tensor 1/2, 1/2 plus +1 over square root of 3, + +1, 1 tensor 1/2, minus 1/2. + +So we have the top +state of the multiplet. + +We have the next state +of the multiplet. + +We have-- I'm sorry, the +top state of the multiplet + +was this. + +You have the bottom +state of the multiplet, + +the middle state +of the multiplet. + +What you're missing is the +bottom and the middle term. + +And this one can be +obtained in many ways. + +One way would be to +raise this state. + +The minus 3/2 could +be raised by one unit + +and do exactly the same thing. + +Well, the result is square root +of 2 over 3, 1, 0 tensor 1/2, + +minus 1/2 plus 1 over +square root of 3. + +That square root of 2 +doesn't look right to me now. + +I must have copied it wrong. + +It's 1 over square root of +3-- 1 over square root of 3, + +1, minus 1 tensor 1/2, 1/2. + +So you've built that +whole multiplet. + +And this state, as we said, +was a linear combination + +of the two possible states. + +This 3 minus 1/2 was +a linear combination + +of these two possible states. + +So the other states +that are left over, + +the other linear +combinations, form + +the J equals 1/2 multiplet. + +So basically, every state must +be orthogonal to each other. + +So the other state, the 1/2, 1/2 +and the 1/2, minus 1/2 of the J + +equals 1/2 multiplet must +be this orthogonal to this. + +And this must be +orthogonal to that. + +So those formulas are easily +found by orthogonality. + +So I'll conclude by +writing them-- minus 1 + +over square root of +3, 1, 0, 1/2, 1/2 + +plus the square root of 2 +over 3, 1, 1, 1/2, minus 1/2. + +And here, you get 1 over +square root of 3, 1, 0, 1/2, + +minus 1/2 minus 2 over +square root of 3, 1, minus 1 + +tensor 1/2, 1/2. + +So lots of terms, a little +hard to read-- I apologize. + +Now, the punchline here is +that you've found these states. + +And the claim is +that these are states + +in which L dot S is diagonal. + +And it's kind of obvious +that that should be the case. + +Because what was L dot S? + +So one last formula-- +L dot S equals + +1/2 of J squared minus L +squared minus S squared. + +Now, in terms of +eigenvalues, this + +is 1/2 h squared J times +J plus 1 minus L times L + +plus 1 minus S times S plus 1. + +Now, all the states +that we built + +have definite +values of J squared, + +definite values of S squared. + +Because L was 1. + +And S is 1/2. + +So here you go h squared over 2 +J times J plus 1 minus 1 times + +2 is 2 minus 1/2 +times 3/2 is 3/4. + +And that's the whole story. + +The whole story in a sense +has been summarized by this. + +We have four states +with J equals 3/2 + +and two states +with J equals 1/2. + +So these six states +that you have here-- + +split because of +this interaction + +into four states that have +J equal to 3/2 and two + +states that have J equal to 1/2. + +And you plug the numbers here. + +And that gives you the +amount of splitting. + +So actually, this height +that this goes up here + +is h squared over 2. + +And this is minus h +squared by the time you + +put the numbers J, 3/2, and 1/2. + +So all our work was because +the Hamiltonian at the end + +was simple in J squared. + +And therefore, we +needed J multiplets. + +J multiplets are the addition +of angular momentum multiplets. + +In a sense, we don't have +to construct these things + +if you don't want to calculate +very explicit details. + +Once you have that, +you have everything. + +This product of angular +momentum 1, angular momentum 1/2 + +gave you total +angular momentum 3/2 + +and 1/2-- four +states, two states. + +So four states split one way, +two states split the other way, + +and that's the end of the story. + +So more of this in recitation +and more of this all + +of next week. + +We'll see you then. \ No newline at end of file diff --git a/ZyDUHHfPBZI.txt b/ZyDUHHfPBZI.txt new file mode 100644 index 0000000000000000000000000000000000000000..87dc5f141cbfaf82c2d0ce5a13bddc67a92f724a --- /dev/null +++ b/ZyDUHHfPBZI.txt @@ -0,0 +1,7835 @@ +align:start position:0% + +all right this is what we were talking + + align:start position:0% +all right this is what we were talking + + + align:start position:0% +all right this is what we were talking +about last time and we're going to + + align:start position:0% +about last time and we're going to + + + align:start position:0% +about last time and we're going to +continue today + + align:start position:0% + + + + align:start position:0% + +the recurring goals that people trying + + align:start position:0% +the recurring goals that people trying + + + align:start position:0% +the recurring goals that people trying +to relate brain and behavior have + + align:start position:0% +to relate brain and behavior have + + + align:start position:0% +to relate brain and behavior have +pursued + + align:start position:0% +pursued + + + align:start position:0% +pursued +we talked last time mainly about the + + align:start position:0% +we talked last time mainly about the + + + align:start position:0% +we talked last time mainly about the +first one specific neural circuits which + + align:start position:0% +first one specific neural circuits which + + + align:start position:0% +first one specific neural circuits which +underlie behavior + + align:start position:0% +underlie behavior + + + align:start position:0% +underlie behavior +another prime example was + + align:start position:0% +another prime example was + + + align:start position:0% +another prime example was +the concept and discovery of the reflex + + align:start position:0% +the concept and discovery of the reflex + + + align:start position:0% +the concept and discovery of the reflex +arc + + align:start position:0% +arc + + + align:start position:0% +arc +which led to the + + align:start position:0% +which led to the + + + align:start position:0% +which led to the +philosophy of life called reflexology + + align:start position:0% + + + + align:start position:0% + +i mentioned that many even the discovery + + align:start position:0% +i mentioned that many even the discovery + + + align:start position:0% +i mentioned that many even the discovery +of reflexes was probably inspired by + + align:start position:0% +of reflexes was probably inspired by + + + align:start position:0% +of reflexes was probably inspired by +human machines + + align:start position:0% +human machines + + + align:start position:0% +human machines +and + + align:start position:0% +and + + + align:start position:0% +and +theory in this field has been influenced + + align:start position:0% +theory in this field has been influenced + + + align:start position:0% +theory in this field has been influenced +by machines for a long time + + align:start position:0% + + + + align:start position:0% + +for example when homeostatic governors + + align:start position:0% +for example when homeostatic governors + + + align:start position:0% +for example when homeostatic governors +were developed + + align:start position:0% +were developed + + + align:start position:0% +were developed +it + + align:start position:0% + + + + align:start position:0% + +it seemed like machines were showing + + align:start position:0% +it seemed like machines were showing + + + align:start position:0% +it seemed like machines were showing +purpose of behavior and that actually + + align:start position:0% +purpose of behavior and that actually + + + align:start position:0% +purpose of behavior and that actually +was a big surprise to many people at + + align:start position:0% +was a big surprise to many people at + + + align:start position:0% +was a big surprise to many people at +that time + + align:start position:0% +that time + + + align:start position:0% +that time +they didn't think a machine could + + align:start position:0% +they didn't think a machine could + + + align:start position:0% +they didn't think a machine could +possibly show purpose and behavior but + + align:start position:0% +possibly show purpose and behavior but + + + align:start position:0% +possibly show purpose and behavior but +of course + + align:start position:0% +of course + + + align:start position:0% +of course +homeostatic governors and servo + + align:start position:0% +homeostatic governors and servo + + + align:start position:0% +homeostatic governors and servo +mechanisms + + align:start position:0% +mechanisms + + + align:start position:0% +mechanisms +and homing devices + + align:start position:0% +and homing devices + + + align:start position:0% +and homing devices +which you're all very familiar with + + align:start position:0% +which you're all very familiar with + + + align:start position:0% +which you're all very familiar with +because you grew up with them but it + + align:start position:0% +because you grew up with them but it + + + align:start position:0% +because you grew up with them but it +wasn't always so obvious to people that + + align:start position:0% +wasn't always so obvious to people that + + + align:start position:0% +wasn't always so obvious to people that +these machines could show purposive + + align:start position:0% +these machines could show purposive + + + align:start position:0% +these machines could show purposive +behavior + + align:start position:0% +behavior + + + align:start position:0% +behavior +homeostatic governors are still a model + + align:start position:0% +homeostatic governors are still a model + + + align:start position:0% +homeostatic governors are still a model +for homeostatic control of visceral + + align:start position:0% +for homeostatic control of visceral + + + align:start position:0% +for homeostatic control of visceral +states physiologists + + align:start position:0% +states physiologists + + + align:start position:0% +states physiologists +now of course the major machine that + + align:start position:0% +now of course the major machine that + + + align:start position:0% +now of course the major machine that +serves as an inspiration to models + + align:start position:0% +serves as an inspiration to models + + + align:start position:0% +serves as an inspiration to models +the computer + + align:start position:0% + + + + align:start position:0% + +and + + align:start position:0% + + + + align:start position:0% + +you'll see that as we + + align:start position:0% +you'll see that as we + + + align:start position:0% +you'll see that as we +come to some simple models for + + align:start position:0% +come to some simple models for + + + align:start position:0% +come to some simple models for +explaining behavior in this class + + align:start position:0% +explaining behavior in this class + + + align:start position:0% +explaining behavior in this class +flow diagrams information flow diagrams + + align:start position:0% +flow diagrams information flow diagrams + + + align:start position:0% +flow diagrams information flow diagrams +are similar to what engineers use + + align:start position:0% + + + + align:start position:0% + +okay now i mentioned descartes and + + align:start position:0% +okay now i mentioned descartes and + + + align:start position:0% +okay now i mentioned descartes and +showed his picture + + align:start position:0% +showed his picture + + + align:start position:0% +showed his picture +i didn't read anything from him + + align:start position:0% + + + + align:start position:0% + +i won't read you the whole quote but the + + align:start position:0% +i won't read you the whole quote but the + + + align:start position:0% +i won't read you the whole quote but the +he talks about these as + + align:start position:0% +he talks about these as + + + align:start position:0% +he talks about these as +little filaments in tubes connected to + + align:start position:0% +little filaments in tubes connected to + + + align:start position:0% +little filaments in tubes connected to +tubes + + align:start position:0% +tubes + + + align:start position:0% +tubes +and + + align:start position:0% + + + + align:start position:0% + +he ends with an analogy after he + + align:start position:0% +he ends with an analogy after he + + + align:start position:0% +he ends with an analogy after he +describes the circuit which as you know + + align:start position:0% +describes the circuit which as you know + + + align:start position:0% +describes the circuit which as you know +wasn't completely accurate anatomically + + align:start position:0% +wasn't completely accurate anatomically + + + align:start position:0% +wasn't completely accurate anatomically +but his concept of the reflex was + + align:start position:0% +but his concept of the reflex was + + + align:start position:0% +but his concept of the reflex was +accurate + + align:start position:0% +accurate + + + align:start position:0% +accurate +he said + + align:start position:0% +he said + + + align:start position:0% +he said +this happens just as by pulling one end + + align:start position:0% +this happens just as by pulling one end + + + align:start position:0% +this happens just as by pulling one end +of the cord + + align:start position:0% +of the cord + + + align:start position:0% +of the cord +one of the ends of the cord you cause a + + align:start position:0% +one of the ends of the cord you cause a + + + align:start position:0% +one of the ends of the cord you cause a +bell attached to the other end to ring + + align:start position:0% +bell attached to the other end to ring + + + align:start position:0% +bell attached to the other end to ring +at the same time + + align:start position:0% +at the same time + + + align:start position:0% +at the same time +so that's the basic idea of a reflex a + + align:start position:0% +so that's the basic idea of a reflex a + + + align:start position:0% +so that's the basic idea of a reflex a +simple stimulus leads in inevitably to a + + align:start position:0% +simple stimulus leads in inevitably to a + + + align:start position:0% +simple stimulus leads in inevitably to a +certain response and it's a fixed + + align:start position:0% +certain response and it's a fixed + + + align:start position:0% +certain response and it's a fixed +relationship + + align:start position:0% + + + + align:start position:0% + +it didn't say anything about the anatomy + + align:start position:0% +it didn't say anything about the anatomy + + + align:start position:0% +it didn't say anything about the anatomy +and the beginnings of understanding the + + align:start position:0% +and the beginnings of understanding the + + + align:start position:0% +and the beginnings of understanding the +anatomy of reflex was the discovery of + + align:start position:0% +anatomy of reflex was the discovery of + + + align:start position:0% +anatomy of reflex was the discovery of +the law of roots + + align:start position:0% +the law of roots + + + align:start position:0% +the law of roots +somebody asked me at the end of the + + align:start position:0% +somebody asked me at the end of the + + + align:start position:0% +somebody asked me at the end of the +class what exactly is the law of roots + + align:start position:0% +class what exactly is the law of roots + + + align:start position:0% +class what exactly is the law of roots +how can you remember that + + align:start position:0% +how can you remember that + + + align:start position:0% +how can you remember that +every spinal nerve as it approaches the + + align:start position:0% +every spinal nerve as it approaches the + + + align:start position:0% +every spinal nerve as it approaches the +cord separates into two major divisions + + align:start position:0% +cord separates into two major divisions + + + align:start position:0% +cord separates into two major divisions +one entering the cord dorsally + + align:start position:0% +one entering the cord dorsally + + + align:start position:0% +one entering the cord dorsally +and the other ventrally + + align:start position:0% +and the other ventrally + + + align:start position:0% +and the other ventrally +okay the dorsal root + + align:start position:0% +okay the dorsal root + + + align:start position:0% +okay the dorsal root +is sensory the ventral root is motor + + align:start position:0% +is sensory the ventral root is motor + + + align:start position:0% +is sensory the ventral root is motor +input dorsally output ventrally how can + + align:start position:0% +input dorsally output ventrally how can + + + align:start position:0% +input dorsally output ventrally how can +you remember that think of a pain in the + + align:start position:0% +you remember that think of a pain in the + + + align:start position:0% +you remember that think of a pain in the +back + + align:start position:0% +back + + + align:start position:0% +back +the pain is towards the back this is + + align:start position:0% +the pain is towards the back this is + + + align:start position:0% +the pain is towards the back this is +dorsal okay this is ventral + + align:start position:0% + + + + align:start position:0% + +pain in the back summarizes what the law + + align:start position:0% +pain in the back summarizes what the law + + + align:start position:0% +pain in the back summarizes what the law +of roots is + + align:start position:0% + + + + align:start position:0% + +and these were the people that + + align:start position:0% +and these were the people that + + + align:start position:0% +and these were the people that +first discovered it + + align:start position:0% + + + + align:start position:0% + +then i talked a little bit about + + align:start position:0% +then i talked a little bit about + + + align:start position:0% +then i talked a little bit about +reflexology and how it originated with + + align:start position:0% +reflexology and how it originated with + + + align:start position:0% +reflexology and how it originated with +people reading the writings of sechinoff + + align:start position:0% +people reading the writings of sechinoff + + + align:start position:0% +people reading the writings of sechinoff +ivan sechenov + + align:start position:0% +ivan sechenov + + + align:start position:0% +ivan sechenov +in russia + + align:start position:0% + + + + align:start position:0% + +and uh + + align:start position:0% + + + + align:start position:0% + +now before that let me describe them a + + align:start position:0% +now before that let me describe them a + + + align:start position:0% +now before that let me describe them a +tree + + align:start position:0% +tree + + + align:start position:0% +tree +what was + + align:start position:0% +what was + + + align:start position:0% +what was +what did i say that + + align:start position:0% +what did i say that + + + align:start position:0% +what did i say that +llama tree's concept of the uniqueness + + align:start position:0% +llama tree's concept of the uniqueness + + + align:start position:0% +llama tree's concept of the uniqueness +of + + align:start position:0% +of + + + align:start position:0% +of +the human laws + + align:start position:0% + + + + align:start position:0% + +right differ from other animals simply + + align:start position:0% +right differ from other animals simply + + + align:start position:0% +right differ from other animals simply +in the complexity of the reflexes + + align:start position:0% +in the complexity of the reflexes + + + align:start position:0% +in the complexity of the reflexes +underlying his behavior + + align:start position:0% + + + + align:start position:0% + +he's well known for a phrase + + align:start position:0% +he's well known for a phrase + + + align:start position:0% +he's well known for a phrase +that is in the following quote + + align:start position:0% +that is in the following quote + + + align:start position:0% +that is in the following quote +let me just read you + + align:start position:0% +let me just read you + + + align:start position:0% +let me just read you +one sentence from a tree translated of + + align:start position:0% +one sentence from a tree translated of + + + align:start position:0% +one sentence from a tree translated of +course + + align:start position:0% +course + + + align:start position:0% +course +since all the faculties of the soul + + align:start position:0% +since all the faculties of the soul + + + align:start position:0% +since all the faculties of the soul +depend with such a degree on the proper + + align:start position:0% +depend with such a degree on the proper + + + align:start position:0% +depend with such a degree on the proper +organization of the brain + + align:start position:0% +organization of the brain + + + align:start position:0% +organization of the brain +and of the whole body + + align:start position:0% +and of the whole body + + + align:start position:0% +and of the whole body +that apparently they are but this + + align:start position:0% +that apparently they are but this + + + align:start position:0% +that apparently they are but this +organization itself the soul is clearly + + align:start position:0% +organization itself the soul is clearly + + + align:start position:0% +organization itself the soul is clearly +an enlightened machine + + align:start position:0% +an enlightened machine + + + align:start position:0% +an enlightened machine +and that phrase the enlightened machine + + align:start position:0% +and that phrase the enlightened machine + + + align:start position:0% +and that phrase the enlightened machine +has been repeated many times even in + + align:start position:0% +has been repeated many times even in + + + align:start position:0% +has been repeated many times even in +modern + + align:start position:0% +modern + + + align:start position:0% +modern +neuroscience + + align:start position:0% +neuroscience + + + align:start position:0% +neuroscience +he can he continued by saying the soul + + align:start position:0% +he can he continued by saying the soul + + + align:start position:0% +he can he continued by saying the soul +is therefore but an empty word + + align:start position:0% + + + + align:start position:0% + +i don't agree with that but that is the + + align:start position:0% +i don't agree with that but that is the + + + align:start position:0% +i don't agree with that but that is the +view of some people + + align:start position:0% + + + + align:start position:0% + +will say a little more about that in a + + align:start position:0% +will say a little more about that in a + + + align:start position:0% +will say a little more about that in a +minute + + align:start position:0% + + + + align:start position:0% + +how did pavlov change that whole picture + + align:start position:0% +how did pavlov change that whole picture + + + align:start position:0% +how did pavlov change that whole picture +and bring + + align:start position:0% +and bring + + + align:start position:0% +and bring +make the influence of reflexology + + align:start position:0% +make the influence of reflexology + + + align:start position:0% +make the influence of reflexology +much more marked in america especially + + align:start position:0% +much more marked in america especially + + + align:start position:0% +much more marked in america especially +the american educational system which + + align:start position:0% +the american educational system which + + + align:start position:0% +the american educational system which +was based on the the idea + + align:start position:0% + + + + align:start position:0% + +plasticity changeability of the reflexes + + align:start position:0% +plasticity changeability of the reflexes + + + align:start position:0% +plasticity changeability of the reflexes +that is the stimulus response model was + + align:start position:0% +that is the stimulus response model was + + + align:start position:0% +that is the stimulus response model was +accepted + + align:start position:0% +accepted + + + align:start position:0% +accepted +often we think of the stimulus response + + align:start position:0% +often we think of the stimulus response + + + align:start position:0% +often we think of the stimulus response +model is sort of a generalization of the + + align:start position:0% +model is sort of a generalization of the + + + align:start position:0% +model is sort of a generalization of the +reflex idea + + align:start position:0% +reflex idea + + + align:start position:0% +reflex idea +that all behavior can be explained by + + align:start position:0% +that all behavior can be explained by + + + align:start position:0% +that all behavior can be explained by +stimuli leading to responses + + align:start position:0% +stimuli leading to responses + + + align:start position:0% +stimuli leading to responses +but the idea that they could be plastic + + align:start position:0% +but the idea that they could be plastic + + + align:start position:0% +but the idea that they could be plastic +but in other words learning could occur + + align:start position:0% + + + + align:start position:0% + +became very important in educational + + align:start position:0% +became very important in educational + + + align:start position:0% +became very important in educational +theory in america where it was believed + + align:start position:0% +theory in america where it was believed + + + align:start position:0% +theory in america where it was believed +that + + align:start position:0% +that + + + align:start position:0% +that +okay animals have instincts but people + + align:start position:0% +okay animals have instincts but people + + + align:start position:0% +okay animals have instincts but people +are plastic + + align:start position:0% +are plastic + + + align:start position:0% +are plastic +and everything can be changed by + + align:start position:0% +and everything can be changed by + + + align:start position:0% +and everything can be changed by +learning + + align:start position:0% + + + + align:start position:0% + +it's not actually + + align:start position:0% +it's not actually + + + align:start position:0% +it's not actually +completely true most things are + + align:start position:0% +completely true most things are + + + align:start position:0% +completely true most things are +is a large instinctive component + + align:start position:0% +is a large instinctive component + + + align:start position:0% +is a large instinctive component +and some of those aspects of the + + align:start position:0% +and some of those aspects of the + + + align:start position:0% +and some of those aspects of the +instincts are not very changeable but in + + align:start position:0% +instincts are not very changeable but in + + + align:start position:0% +instincts are not very changeable but in +fact most behaviors there's some + + align:start position:0% +fact most behaviors there's some + + + align:start position:0% +fact most behaviors there's some +influence of experience as well as of + + align:start position:0% +influence of experience as well as of + + + align:start position:0% +influence of experience as well as of +built-in connections + + align:start position:0% + + + + align:start position:0% + +i mentioned makai + + align:start position:0% +i mentioned makai + + + align:start position:0% +i mentioned makai +and i posted his reading one one paper + + align:start position:0% +and i posted his reading one one paper + + + align:start position:0% +and i posted his reading one one paper +by him on the web + + align:start position:0% +by him on the web + + + align:start position:0% +by him on the web +who argued that a strict determinism + + align:start position:0% + + + + align:start position:0% + +determinism he could accept but then he + + align:start position:0% +determinism he could accept but then he + + + align:start position:0% +determinism he could accept but then he +said + + align:start position:0% +said + + + align:start position:0% +said +in the strict sense + + align:start position:0% +in the strict sense + + + align:start position:0% +in the strict sense +it's logically impossible because + + align:start position:0% +it's logically impossible because + + + align:start position:0% +it's logically impossible because +it doesn't allow you to say a person is + + align:start position:0% +it doesn't allow you to say a person is + + + align:start position:0% +it doesn't allow you to say a person is +responsible for his actions and so i'm + + align:start position:0% +responsible for his actions and so i'm + + + align:start position:0% +responsible for his actions and so i'm +asking you some questions about that + + align:start position:0% +asking you some questions about that + + + align:start position:0% +asking you some questions about that +here that i've added + + align:start position:0% + + + + align:start position:0% + +does this mean that some things are not + + align:start position:0% +does this mean that some things are not + + + align:start position:0% +does this mean that some things are not +determined by awful cause effect + + align:start position:0% +determined by awful cause effect + + + align:start position:0% +determined by awful cause effect +relationships no that's not what he + + align:start position:0% +relationships no that's not what he + + + align:start position:0% +relationships no that's not what he +means + + align:start position:0% +means + + + align:start position:0% +means +okay + + align:start position:0% +okay + + + align:start position:0% +okay +well then why should a person be held + + align:start position:0% +well then why should a person be held + + + align:start position:0% +well then why should a person be held +responsible for something that + + align:start position:0% +responsible for something that + + + align:start position:0% +responsible for something that +necessarily had to occur once the + + align:start position:0% +necessarily had to occur once the + + + align:start position:0% +necessarily had to occur once the +conditions were there once the stage was + + align:start position:0% +conditions were there once the stage was + + + align:start position:0% +conditions were there once the stage was +set + + align:start position:0% +set + + + align:start position:0% +set +this is a question in forensic + + align:start position:0% +this is a question in forensic + + + align:start position:0% +this is a question in forensic +psychiatry + + align:start position:0% +psychiatry + + + align:start position:0% +psychiatry +it's why psychiatrists + + align:start position:0% +it's why psychiatrists + + + align:start position:0% +it's why psychiatrists +are asked to come in the courtroom + + align:start position:0% +are asked to come in the courtroom + + + align:start position:0% +are asked to come in the courtroom +sometimes + + align:start position:0% +sometimes + + + align:start position:0% +sometimes +testify that someone was + + align:start position:0% +testify that someone was + + + align:start position:0% +testify that someone was +too crazy to be responsible for his + + align:start position:0% +too crazy to be responsible for his + + + align:start position:0% +too crazy to be responsible for his +actions + + align:start position:0% +actions + + + align:start position:0% +actions +or some other + + align:start position:0% +or some other + + + align:start position:0% +or some other +problem he had some other problem + + align:start position:0% +problem he had some other problem + + + align:start position:0% +problem he had some other problem +but i would argue that + + align:start position:0% + + + + align:start position:0% + +if everything is determined then the + + align:start position:0% +if everything is determined then the + + + align:start position:0% +if everything is determined then the +culpability and the punishments are also + + align:start position:0% +culpability and the punishments are also + + + align:start position:0% +culpability and the punishments are also +determined + + align:start position:0% +determined + + + align:start position:0% +determined +and they also must necessarily occur by + + align:start position:0% +and they also must necessarily occur by + + + align:start position:0% +and they also must necessarily occur by +the same kind of deterministic laws + + align:start position:0% +the same kind of deterministic laws + + + align:start position:0% +the same kind of deterministic laws +so you can't have part of one + + align:start position:0% +so you can't have part of one + + + align:start position:0% +so you can't have part of one +you see + + align:start position:0% +you see + + + align:start position:0% +you see +without the other so + + align:start position:0% +without the other so + + + align:start position:0% +without the other so +i like makai's argument + + align:start position:0% +i like makai's argument + + + align:start position:0% +i like makai's argument +even though some people + + align:start position:0% +even though some people + + + align:start position:0% +even though some people +don't i think it helps us it points out + + align:start position:0% +don't i think it helps us it points out + + + align:start position:0% +don't i think it helps us it points out +a logical conundrum that we are always + + align:start position:0% +a logical conundrum that we are always + + + align:start position:0% +a logical conundrum that we are always +faced with in this field + + align:start position:0% +faced with in this field + + + align:start position:0% +faced with in this field +okay + + align:start position:0% + + + + align:start position:0% + +why did people move to a different kind + + align:start position:0% +why did people move to a different kind + + + align:start position:0% +why did people move to a different kind +of goal giving up the idea of specific + + align:start position:0% +of goal giving up the idea of specific + + + align:start position:0% +of goal giving up the idea of specific +neural circuits underlying behavior + + align:start position:0% + + + + align:start position:0% + +it's because they thought the first goal + + align:start position:0% +it's because they thought the first goal + + + align:start position:0% +it's because they thought the first goal +was a pipe dream it was impossible + + align:start position:0% +was a pipe dream it was impossible + + + align:start position:0% +was a pipe dream it was impossible +how could we ever trace these + + align:start position:0% +how could we ever trace these + + + align:start position:0% +how could we ever trace these +connections between + + align:start position:0% +connections between + + + align:start position:0% +connections between +the input and the output stimulus and + + align:start position:0% +the input and the output stimulus and + + + align:start position:0% +the input and the output stimulus and +response + + align:start position:0% +response + + + align:start position:0% +response +in the human brain where there's 10 + + align:start position:0% +in the human brain where there's 10 + + + align:start position:0% +in the human brain where there's 10 +billion + + align:start position:0% +billion + + + align:start position:0% +billion +nerve cells at least + + align:start position:0% + + + + align:start position:0% + +there's actually many more than that it + + align:start position:0% +there's actually many more than that it + + + align:start position:0% +there's actually many more than that it +was once that was the number always + + align:start position:0% +was once that was the number always + + + align:start position:0% +was once that was the number always +given then they discovered there were + + align:start position:0% +given then they discovered there were + + + align:start position:0% +given then they discovered there were +more than that just in the cerebellum + + align:start position:0% + + + + align:start position:0% + +and that says + + align:start position:0% +and that says + + + align:start position:0% +and that says +the number of connections is much much + + align:start position:0% +the number of connections is much much + + + align:start position:0% +the number of connections is much much +greater + + align:start position:0% +greater + + + align:start position:0% +greater +one study was done some years ago with + + align:start position:0% +one study was done some years ago with + + + align:start position:0% +one study was done some years ago with +the electron microscope looking at the + + align:start position:0% +the electron microscope looking at the + + + align:start position:0% +the electron microscope looking at the +monkey neocortex + + align:start position:0% +monkey neocortex + + + align:start position:0% +monkey neocortex +it should say motor cortex + + align:start position:0% +it should say motor cortex + + + align:start position:0% +it should say motor cortex +in the monkey motor cortex where it was + + align:start position:0% +in the monkey motor cortex where it was + + + align:start position:0% +in the monkey motor cortex where it was +found we'll mention motor cortex in a + + align:start position:0% +found we'll mention motor cortex in a + + + align:start position:0% +found we'll mention motor cortex in a +few minutes + + align:start position:0% +few minutes + + + align:start position:0% +few minutes +it was found that on the average one + + align:start position:0% +it was found that on the average one + + + align:start position:0% +it was found that on the average one +neuron had 60 000 inputs that is 60 000 + + align:start position:0% +neuron had 60 000 inputs that is 60 000 + + + align:start position:0% +neuron had 60 000 inputs that is 60 000 +synapses on its surfaces + + align:start position:0% +synapses on its surfaces + + + align:start position:0% +synapses on its surfaces +in the monkey visual cortex it was four + + align:start position:0% +in the monkey visual cortex it was four + + + align:start position:0% +in the monkey visual cortex it was four +thousand + + align:start position:0% +thousand + + + align:start position:0% +thousand +but if you take + + align:start position:0% +but if you take + + + align:start position:0% +but if you take +those are probably the extremes in the + + align:start position:0% +those are probably the extremes in the + + + align:start position:0% +those are probably the extremes in the +neocortex but it gives you an idea + + align:start position:0% +neocortex but it gives you an idea + + + align:start position:0% +neocortex but it gives you an idea +enormous numbers and connections + + align:start position:0% + + + + align:start position:0% + +the task of specifying circuitry + + align:start position:0% +the task of specifying circuitry + + + align:start position:0% +the task of specifying circuitry +is pretty formidable even in the spinal + + align:start position:0% +is pretty formidable even in the spinal + + + align:start position:0% +is pretty formidable even in the spinal +cord + + align:start position:0% +cord + + + align:start position:0% +cord +but their reflex ideas can explain many + + align:start position:0% +but their reflex ideas can explain many + + + align:start position:0% +but their reflex ideas can explain many +reactions and that's been known since + + align:start position:0% +reactions and that's been known since + + + align:start position:0% +reactions and that's been known since +the detailed studies of + + align:start position:0% +the detailed studies of + + + align:start position:0% +the detailed studies of +charles scott sherrington around the + + align:start position:0% +charles scott sherrington around the + + + align:start position:0% +charles scott sherrington around the +turn of the + + align:start position:0% +turn of the + + + align:start position:0% +turn of the +previous century 1900 + + align:start position:0% +previous century 1900 + + + align:start position:0% +previous century 1900 +the man that coined the term synapse + + align:start position:0% + + + + align:start position:0% + +so what else can we do if it's so + + align:start position:0% +so what else can we do if it's so + + + align:start position:0% +so what else can we do if it's so +difficult to trace connections + + align:start position:0% +difficult to trace connections + + + align:start position:0% +difficult to trace connections +from s to r + + align:start position:0% +from s to r + + + align:start position:0% +from s to r +connections that underlie behavior well + + align:start position:0% +connections that underlie behavior well + + + align:start position:0% +connections that underlie behavior well +many people have simply pursued a very + + align:start position:0% +many people have simply pursued a very + + + align:start position:0% +many people have simply pursued a very +different kind of goal localizing + + align:start position:0% +different kind of goal localizing + + + align:start position:0% +different kind of goal localizing +function in specific parts of the + + align:start position:0% +function in specific parts of the + + + align:start position:0% +function in specific parts of the +central nervous system brain and spinal + + align:start position:0% +central nervous system brain and spinal + + + align:start position:0% +central nervous system brain and spinal +cord + + align:start position:0% +cord + + + align:start position:0% +cord +without necessarily any + + align:start position:0% +without necessarily any + + + align:start position:0% +without necessarily any +specification of circuitry within + + align:start position:0% +specification of circuitry within + + + align:start position:0% +specification of circuitry within +a functional subdivision or even be + + align:start position:0% +a functional subdivision or even be + + + align:start position:0% +a functional subdivision or even be +sometimes not even between them + + align:start position:0% +sometimes not even between them + + + align:start position:0% +sometimes not even between them +although the modern + + align:start position:0% +although the modern + + + align:start position:0% +although the modern +synthesis often tries to at least + + align:start position:0% +synthesis often tries to at least + + + align:start position:0% +synthesis often tries to at least +specify connections between the major + + align:start position:0% +specify connections between the major + + + align:start position:0% +specify connections between the major +functional divisions of the brain + + align:start position:0% + + + + align:start position:0% + +this kind of goal + + align:start position:0% +this kind of goal + + + align:start position:0% +this kind of goal +started out with simple arguments about + + align:start position:0% +started out with simple arguments about + + + align:start position:0% +started out with simple arguments about +where the seed of the soul was + + align:start position:0% +where the seed of the soul was + + + align:start position:0% +where the seed of the soul was +but then + + align:start position:0% +but then + + + align:start position:0% +but then +we'll see how localization + + align:start position:0% +we'll see how localization + + + align:start position:0% +we'll see how localization +took on a very different form and + + align:start position:0% +took on a very different form and + + + align:start position:0% +took on a very different form and +detailed mosaic maps the brain were + + align:start position:0% +detailed mosaic maps the brain were + + + align:start position:0% +detailed mosaic maps the brain were +developed + + align:start position:0% +developed + + + align:start position:0% +developed +but there was an opposing type of idea + + align:start position:0% +but there was an opposing type of idea + + + align:start position:0% +but there was an opposing type of idea +that we'll cover also i don't know if + + align:start position:0% +that we'll cover also i don't know if + + + align:start position:0% +that we'll cover also i don't know if +we'll get to it today we call it it's + + align:start position:0% +we'll get to it today we call it it's + + + align:start position:0% +we'll get to it today we call it it's +sometimes called anti-localization + + align:start position:0% +sometimes called anti-localization + + + align:start position:0% +sometimes called anti-localization +because they didn't believe that you + + align:start position:0% +because they didn't believe that you + + + align:start position:0% +because they didn't believe that you +could localize functions so easily in + + align:start position:0% +could localize functions so easily in + + + align:start position:0% +could localize functions so easily in +different parts of the brain but they + + align:start position:0% +different parts of the brain but they + + + align:start position:0% +different parts of the brain but they +did have a kind of general localization + + align:start position:0% +did have a kind of general localization + + + align:start position:0% +did have a kind of general localization +and i'll explain what that means + + align:start position:0% + + + + align:start position:0% + +the seed of the + + align:start position:0% +the seed of the + + + align:start position:0% +the seed of the +soul is exemplified by a quote from + + align:start position:0% +soul is exemplified by a quote from + + + align:start position:0% +soul is exemplified by a quote from +shakespeare and the merchant of venice + + align:start position:0% +shakespeare and the merchant of venice + + + align:start position:0% +shakespeare and the merchant of venice +who asked tell me where is fancy bread + + align:start position:0% +who asked tell me where is fancy bread + + + align:start position:0% +who asked tell me where is fancy bread +in the heart or in the head + + align:start position:0% +in the heart or in the head + + + align:start position:0% +in the heart or in the head +but the ideal as well + + align:start position:0% +but the ideal as well + + + align:start position:0% +but the ideal as well +is it in the brain or is it in the heart + + align:start position:0% +is it in the brain or is it in the heart + + + align:start position:0% +is it in the brain or is it in the heart +that we have feeling or that we have + + align:start position:0% +that we have feeling or that we have + + + align:start position:0% +that we have feeling or that we have +imagination or whatever it wasn't always + + align:start position:0% +imagination or whatever it wasn't always + + + align:start position:0% +imagination or whatever it wasn't always +so clear to people + + align:start position:0% + + + + align:start position:0% + +although there were many + + align:start position:0% +although there were many + + + align:start position:0% +although there were many +many people that correctly assumed it + + align:start position:0% +many people that correctly assumed it + + + align:start position:0% +many people that correctly assumed it +was in something in the head + + align:start position:0% +was in something in the head + + + align:start position:0% +was in something in the head +in many different cultures + + align:start position:0% + + + + align:start position:0% + +but there were many arguments because we + + align:start position:0% +but there were many arguments because we + + + align:start position:0% +but there were many arguments because we +seem to feel + + align:start position:0% +seem to feel + + + align:start position:0% +seem to feel +feelings in particular + + align:start position:0% +feelings in particular + + + align:start position:0% +feelings in particular +not here but here or throughout our body + + align:start position:0% +not here but here or throughout our body + + + align:start position:0% +not here but here or throughout our body +okay + + align:start position:0% + + + + align:start position:0% + +this is a picture from leonardo leonardo + + align:start position:0% +this is a picture from leonardo leonardo + + + align:start position:0% +this is a picture from leonardo leonardo +da vinci + + align:start position:0% +da vinci + + + align:start position:0% +da vinci +who + + align:start position:0% +who + + + align:start position:0% +who +has this picture an outline of the brain + + align:start position:0% +has this picture an outline of the brain + + + align:start position:0% +has this picture an outline of the brain +very large but he's stressing the + + align:start position:0% +very large but he's stressing the + + + align:start position:0% +very large but he's stressing the +ventricles + + align:start position:0% +ventricles + + + align:start position:0% +ventricles +the ventricles are the fluid filled + + align:start position:0% +the ventricles are the fluid filled + + + align:start position:0% +the ventricles are the fluid filled +cavities + + align:start position:0% +cavities + + + align:start position:0% +cavities +in the central center part of the brain + + align:start position:0% +in the central center part of the brain + + + align:start position:0% +in the central center part of the brain +and spinal cord + + align:start position:0% +and spinal cord + + + align:start position:0% +and spinal cord +and to many people + + align:start position:0% +and to many people + + + align:start position:0% +and to many people +it seemed appropriate that they didn't + + align:start position:0% +it seemed appropriate that they didn't + + + align:start position:0% +it seemed appropriate that they didn't +know they were filled with fluid they + + align:start position:0% +know they were filled with fluid they + + + align:start position:0% +know they were filled with fluid they +thought like they might be filled with a + + align:start position:0% +thought like they might be filled with a + + + align:start position:0% +thought like they might be filled with a +kind of gas and they thought that was + + align:start position:0% +kind of gas and they thought that was + + + align:start position:0% +kind of gas and they thought that was +very appropriate for the soul + + align:start position:0% +very appropriate for the soul + + + align:start position:0% +very appropriate for the soul +you see it wasn't + + align:start position:0% +you see it wasn't + + + align:start position:0% +you see it wasn't +didn't seem so physical + + align:start position:0% + + + + align:start position:0% + +in fact descartes was influenced by that + + align:start position:0% +in fact descartes was influenced by that + + + align:start position:0% +in fact descartes was influenced by that +kind of idea + + align:start position:0% + + + + align:start position:0% + +the idea of localizing functions and + + align:start position:0% +the idea of localizing functions and + + + align:start position:0% +the idea of localizing functions and +specifically in different parts of the + + align:start position:0% +specifically in different parts of the + + + align:start position:0% +specifically in different parts of the +brain really got its first strong + + align:start position:0% +brain really got its first strong + + + align:start position:0% +brain really got its first strong +impetus from + + align:start position:0% +impetus from + + + align:start position:0% +impetus from +what we now would call a false science + + align:start position:0% +what we now would call a false science + + + align:start position:0% +what we now would call a false science +the science called phrenology + + align:start position:0% +the science called phrenology + + + align:start position:0% +the science called phrenology +prince joseph gaul was a neuroanatomist + + align:start position:0% +prince joseph gaul was a neuroanatomist + + + align:start position:0% +prince joseph gaul was a neuroanatomist +well let's say an anatomist he wasn't + + align:start position:0% +well let's say an anatomist he wasn't + + + align:start position:0% +well let's say an anatomist he wasn't +really a neuroanatomist but he's known + + align:start position:0% +really a neuroanatomist but he's known + + + align:start position:0% +really a neuroanatomist but he's known +for + + align:start position:0% +for + + + align:start position:0% +for +being the first one to separate gray and + + align:start position:0% +being the first one to separate gray and + + + align:start position:0% +being the first one to separate gray and +white matter + + align:start position:0% +white matter + + + align:start position:0% +white matter +in his dissections of the brain + + align:start position:0% +in his dissections of the brain + + + align:start position:0% +in his dissections of the brain +and a follower of his in america + + align:start position:0% +and a follower of his in america + + + align:start position:0% +and a follower of his in america +spurtzheim helped to popularize + + align:start position:0% +spurtzheim helped to popularize + + + align:start position:0% +spurtzheim helped to popularize +the ideas + + align:start position:0% +the ideas + + + align:start position:0% +the ideas +that + + align:start position:0% + + + + align:start position:0% + +the shape of the skull somehow + + align:start position:0% +the shape of the skull somehow + + + align:start position:0% +the shape of the skull somehow +represents character because it + + align:start position:0% +represents character because it + + + align:start position:0% +represents character because it +corresponds to different parts the + + align:start position:0% +corresponds to different parts the + + + align:start position:0% +corresponds to different parts the +underlying brain + + align:start position:0% + + + + align:start position:0% + +and here's one of their maps this became + + align:start position:0% +and here's one of their maps this became + + + align:start position:0% +and here's one of their maps this became +very popular + + align:start position:0% +very popular + + + align:start position:0% +very popular +and + + align:start position:0% + + + + align:start position:0% + +not just in the 19th century but it + + align:start position:0% +not just in the 19th century but it + + + align:start position:0% +not just in the 19th century but it +continued into the 20th century and + + align:start position:0% +continued into the 20th century and + + + align:start position:0% +continued into the 20th century and +you'll find books of phrenology + + align:start position:0% +you'll find books of phrenology + + + align:start position:0% +you'll find books of phrenology +on some of your parents or grandparents + + align:start position:0% +on some of your parents or grandparents + + + align:start position:0% +on some of your parents or grandparents +shelves + + align:start position:0% +shelves + + + align:start position:0% +shelves +and they also sold these little models + + align:start position:0% +and they also sold these little models + + + align:start position:0% +and they also sold these little models +like + + align:start position:0% +like + + + align:start position:0% +like +that look something like this + + align:start position:0% + + + + align:start position:0% + +with the skull divided up they what they + + align:start position:0% +with the skull divided up they what they + + + align:start position:0% +with the skull divided up they what they +claimed was that simply by feeling the + + align:start position:0% +claimed was that simply by feeling the + + + align:start position:0% +claimed was that simply by feeling the +prominences and the bumps on your skull + + align:start position:0% +prominences and the bumps on your skull + + + align:start position:0% +prominences and the bumps on your skull +you could say something about character + + align:start position:0% + + + + align:start position:0% + +what on earth was that based on + + align:start position:0% + + + + align:start position:0% + +this is another one of the pictures + + align:start position:0% +this is another one of the pictures + + + align:start position:0% +this is another one of the pictures +where they're depicting the various + + align:start position:0% +where they're depicting the various + + + align:start position:0% +where they're depicting the various +functions + + align:start position:0% + + + + align:start position:0% + +in this graphical format + + align:start position:0% + + + + align:start position:0% + +well they made certain assumptions + + align:start position:0% +well they made certain assumptions + + + align:start position:0% +well they made certain assumptions +and we don't argue with all of those + + align:start position:0% +and we don't argue with all of those + + + align:start position:0% +and we don't argue with all of those +assumptions now + + align:start position:0% +assumptions now + + + align:start position:0% +assumptions now +they said the brain is the sole organ of + + align:start position:0% +they said the brain is the sole organ of + + + align:start position:0% +they said the brain is the sole organ of +the mind it's not in the heart it's not + + align:start position:0% +the mind it's not in the heart it's not + + + align:start position:0% +the mind it's not in the heart it's not +elsewhere it's all in the brain + + align:start position:0% +elsewhere it's all in the brain + + + align:start position:0% +elsewhere it's all in the brain +and we don't argue with that now for the + + align:start position:0% +and we don't argue with that now for the + + + align:start position:0% +and we don't argue with that now for the +most part + + align:start position:0% +most part + + + align:start position:0% +most part +they also argued that basic character + + align:start position:0% +they also argued that basic character + + + align:start position:0% +they also argued that basic character +traits were innate + + align:start position:0% +traits were innate + + + align:start position:0% +traits were innate +something we're born with + + align:start position:0% +something we're born with + + + align:start position:0% +something we're born with +well + + align:start position:0% +well + + + align:start position:0% +well +there's a large degree of truth to that + + align:start position:0% +there's a large degree of truth to that + + + align:start position:0% +there's a large degree of truth to that +too + + align:start position:0% +too + + + align:start position:0% +too +we may be shaped by experience but in + + align:start position:0% +we may be shaped by experience but in + + + align:start position:0% +we may be shaped by experience but in +fact + + align:start position:0% +fact + + + align:start position:0% +fact +basic character traits are built-in + + align:start position:0% +basic character traits are built-in + + + align:start position:0% +basic character traits are built-in +they're genetic + + align:start position:0% +they're genetic + + + align:start position:0% +they're genetic +because the brain structure the basic + + align:start position:0% +because the brain structure the basic + + + align:start position:0% +because the brain structure the basic +structure of the brain is inherited + + align:start position:0% + + + + align:start position:0% + +the third assumption was the differences + + align:start position:0% +the third assumption was the differences + + + align:start position:0% +the third assumption was the differences +in characters and ability imply + + align:start position:0% +in characters and ability imply + + + align:start position:0% +in characters and ability imply +differences in structure + + align:start position:0% + + + + align:start position:0% + +and just going that far + + align:start position:0% +and just going that far + + + align:start position:0% +and just going that far +i think many people would in + + align:start position:0% +i think many people would in + + + align:start position:0% +i think many people would in +neuroscience would still agree with that + + align:start position:0% +neuroscience would still agree with that + + + align:start position:0% +neuroscience would still agree with that +but then they said that that was + + align:start position:0% +but then they said that that was + + + align:start position:0% +but then they said that that was +manifest mainly as differences in size + + align:start position:0% +manifest mainly as differences in size + + + align:start position:0% +manifest mainly as differences in size +well there are a number of examples + + align:start position:0% +well there are a number of examples + + + align:start position:0% +well there are a number of examples +where functional differences are + + align:start position:0% +where functional differences are + + + align:start position:0% +where functional differences are +correlated with differences in size + + align:start position:0% +correlated with differences in size + + + align:start position:0% +correlated with differences in size +and i talk about a few of those later in + + align:start position:0% +and i talk about a few of those later in + + + align:start position:0% +and i talk about a few of those later in +the class and in the second term also + + align:start position:0% +the class and in the second term also + + + align:start position:0% +the class and in the second term also +but there are so many exceptions to that + + align:start position:0% +but there are so many exceptions to that + + + align:start position:0% +but there are so many exceptions to that +also + + align:start position:0% +also + + + align:start position:0% +also +the final + + align:start position:0% +the final + + + align:start position:0% +the final +assumption and this is the one + + align:start position:0% +assumption and this is the one + + + align:start position:0% +assumption and this is the one +that was the most wrong that shaped the + + align:start position:0% +that was the most wrong that shaped the + + + align:start position:0% +that was the most wrong that shaped the +shape the brains correlated with the + + align:start position:0% +shape the brains correlated with the + + + align:start position:0% +shape the brains correlated with the +shape of the skull but wait a minute i + + align:start position:0% +shape of the skull but wait a minute i + + + align:start position:0% +shape of the skull but wait a minute i +mean our brain is shaped pretty much + + align:start position:0% +mean our brain is shaped pretty much + + + align:start position:0% +mean our brain is shaped pretty much +like our skull + + align:start position:0% +like our skull + + + align:start position:0% +like our skull +but what about details + + align:start position:0% +but what about details + + + align:start position:0% +but what about details +well + + align:start position:0% +well + + + align:start position:0% +well +we're very thick skulled species + + align:start position:0% +we're very thick skulled species + + + align:start position:0% +we're very thick skulled species +and + + align:start position:0% +and + + + align:start position:0% +and +we can't tell too much about details of + + align:start position:0% +we can't tell too much about details of + + + align:start position:0% +we can't tell too much about details of +shape + + align:start position:0% +shape + + + align:start position:0% +shape +by looking in the outside of the brain + + align:start position:0% +by looking in the outside of the brain + + + align:start position:0% +by looking in the outside of the brain +if we look at the inside of the outside + + align:start position:0% +if we look at the inside of the outside + + + align:start position:0% +if we look at the inside of the outside +of the skull but if we look at the + + align:start position:0% +of the skull but if we look at the + + + align:start position:0% +of the skull but if we look at the +inside of the skull + + align:start position:0% +inside of the skull + + + align:start position:0% +inside of the skull +and people in anthropology use that of + + align:start position:0% +and people in anthropology use that of + + + align:start position:0% +and people in anthropology use that of +this method of making what they call an + + align:start position:0% +this method of making what they call an + + + align:start position:0% +this method of making what they call an +endocranial cast + + align:start position:0% +endocranial cast + + + align:start position:0% +endocranial cast +the cast made from the inside of a skull + + align:start position:0% +the cast made from the inside of a skull + + + align:start position:0% +the cast made from the inside of a skull +you can actually see quite a bit about + + align:start position:0% +you can actually see quite a bit about + + + align:start position:0% +you can actually see quite a bit about +major features of the external surface + + align:start position:0% +major features of the external surface + + + align:start position:0% +major features of the external surface +of the brain we can tell where certain + + align:start position:0% +of the brain we can tell where certain + + + align:start position:0% +of the brain we can tell where certain +major vessels were located major + + align:start position:0% +major vessels were located major + + + align:start position:0% +major vessels were located major +fissures in + + align:start position:0% +fissures in + + + align:start position:0% +fissures in +people who have not existed for many + + align:start position:0% +people who have not existed for many + + + align:start position:0% +people who have not existed for many +thousands of years + + align:start position:0% + + + + align:start position:0% + +well + + align:start position:0% +well + + + align:start position:0% +well +so their assumptions were + + align:start position:0% +so their assumptions were + + + align:start position:0% +so their assumptions were +true or partially true + + align:start position:0% +true or partially true + + + align:start position:0% +true or partially true +but their methods + + align:start position:0% +but their methods + + + align:start position:0% +but their methods +were not what we would call scientific + + align:start position:0% + + + + align:start position:0% + +there + + align:start position:0% + + + + align:start position:0% + +they practiced what i suppose you could + + align:start position:0% +they practiced what i suppose you could + + + align:start position:0% +they practiced what i suppose you could +call newspaper science + + align:start position:0% +call newspaper science + + + align:start position:0% +call newspaper science +they collected anecdotes and then used + + align:start position:0% +they collected anecdotes and then used + + + align:start position:0% +they collected anecdotes and then used +it to argue immediately for + + align:start position:0% + + + + align:start position:0% + +the generality of the phenomenon + + align:start position:0% +the generality of the phenomenon + + + align:start position:0% +the generality of the phenomenon +for example + + align:start position:0% +for example + + + align:start position:0% +for example +you would read in their book about + + align:start position:0% +you would read in their book about + + + align:start position:0% +you would read in their book about +a student who is + + align:start position:0% +a student who is + + + align:start position:0% +a student who is +discovered to be torturing animals and + + align:start position:0% +discovered to be torturing animals and + + + align:start position:0% +discovered to be torturing animals and +he was found to have + + align:start position:0% +he was found to have + + + align:start position:0% +he was found to have +you know to have prominence above his + + align:start position:0% +you know to have prominence above his + + + align:start position:0% +you know to have prominence above his +ears so they concluded that that area + + align:start position:0% +ears so they concluded that that area + + + align:start position:0% +ears so they concluded that that area +if it's prominent corresponds to + + align:start position:0% +if it's prominent corresponds to + + + align:start position:0% +if it's prominent corresponds to +that character trait + + align:start position:0% +that character trait + + + align:start position:0% +that character trait +that's an anecdote and of course there's + + align:start position:0% +that's an anecdote and of course there's + + + align:start position:0% +that's an anecdote and of course there's +nothing general about it they didn't do + + align:start position:0% +nothing general about it they didn't do + + + align:start position:0% +nothing general about it they didn't do +the statistics you would need i'm not + + align:start position:0% +the statistics you would need i'm not + + + align:start position:0% +the statistics you would need i'm not +saying that there might not be some + + align:start position:0% +saying that there might not be some + + + align:start position:0% +saying that there might not be some +correlates that could be found like that + + align:start position:0% +correlates that could be found like that + + + align:start position:0% +correlates that could be found like that +and there are people that still pursue + + align:start position:0% +and there are people that still pursue + + + align:start position:0% +and there are people that still pursue +that kind of thing + + align:start position:0% +that kind of thing + + + align:start position:0% +that kind of thing +but their methods were simply anecdotal + + align:start position:0% +but their methods were simply anecdotal + + + align:start position:0% +but their methods were simply anecdotal +and can't be dependent on + + align:start position:0% +and can't be dependent on + + + align:start position:0% +and can't be dependent on +so why do we talk about it then + + align:start position:0% +so why do we talk about it then + + + align:start position:0% +so why do we talk about it then +it was very important in the history of + + align:start position:0% +it was very important in the history of + + + align:start position:0% +it was very important in the history of +the field because it drew attention to + + align:start position:0% +the field because it drew attention to + + + align:start position:0% +the field because it drew attention to +brain behavior relationships + + align:start position:0% +brain behavior relationships + + + align:start position:0% +brain behavior relationships +and it + + align:start position:0% +and it + + + align:start position:0% +and it +it made successors + + align:start position:0% +it made successors + + + align:start position:0% +it made successors +who talked about + + align:start position:0% + + + + align:start position:0% + +more believable data + + align:start position:0% +more believable data + + + align:start position:0% +more believable data +correlating structure and function it + + align:start position:0% +correlating structure and function it + + + align:start position:0% +correlating structure and function it +made them seem more made them + + align:start position:0% +made them seem more made them + + + align:start position:0% +made them seem more made them +conservative and made it easier to + + align:start position:0% +conservative and made it easier to + + + align:start position:0% +conservative and made it easier to +believe + + align:start position:0% + + + + align:start position:0% + +so it was a popular thing that called + + align:start position:0% +so it was a popular thing that called + + + align:start position:0% +so it was a popular thing that called +attention + + align:start position:0% +attention + + + align:start position:0% +attention +to brain behavior relationships and lynn + + align:start position:0% +to brain behavior relationships and lynn + + + align:start position:0% +to brain behavior relationships and lynn +made it easier for what followed + + align:start position:0% +made it easier for what followed + + + align:start position:0% +made it easier for what followed +let's talk about some of the later + + align:start position:0% +let's talk about some of the later + + + align:start position:0% +let's talk about some of the later +discoveries beginning with the speech + + align:start position:0% +discoveries beginning with the speech + + + align:start position:0% +discoveries beginning with the speech +areas paul broca + + align:start position:0% +areas paul broca + + + align:start position:0% +areas paul broca +in 1861 published cases and i'm not + + align:start position:0% +in 1861 published cases and i'm not + + + align:start position:0% +in 1861 published cases and i'm not +showing his cases + + align:start position:0% +showing his cases + + + align:start position:0% +showing his cases +but what broca said was + + align:start position:0% +but what broca said was + + + align:start position:0% +but what broca said was +he had certain he was a neurologist he + + align:start position:0% +he had certain he was a neurologist he + + + align:start position:0% +he had certain he was a neurologist he +said i had certain patients that + + align:start position:0% +said i had certain patients that + + + align:start position:0% +said i had certain patients that +could not speak after suffering brain + + align:start position:0% +could not speak after suffering brain + + + align:start position:0% +could not speak after suffering brain +damage + + align:start position:0% +damage + + + align:start position:0% +damage +okay they had strokes + + align:start position:0% +okay they had strokes + + + align:start position:0% +okay they had strokes +and they were rendered + + align:start position:0% +and they were rendered + + + align:start position:0% +and they were rendered +speechless they couldn't get any words + + align:start position:0% +speechless they couldn't get any words + + + align:start position:0% +speechless they couldn't get any words +out + + align:start position:0% +out + + + align:start position:0% +out +and yet they seemed to be able to + + align:start position:0% +and yet they seemed to be able to + + + align:start position:0% +and yet they seemed to be able to +understand speech + + align:start position:0% +understand speech + + + align:start position:0% +understand speech +but they couldn't speak + + align:start position:0% + + + + align:start position:0% + +he found that there was some consistency + + align:start position:0% +he found that there was some consistency + + + align:start position:0% +he found that there was some consistency +in + + align:start position:0% +in + + + align:start position:0% +in +the more than one patient that he looked + + align:start position:0% +the more than one patient that he looked + + + align:start position:0% +the more than one patient that he looked +at they had damage in the left + + align:start position:0% +at they had damage in the left + + + align:start position:0% +at they had damage in the left +hemisphere + + align:start position:0% +hemisphere + + + align:start position:0% +hemisphere +in the frontal lobe in the ventral part + + align:start position:0% +in the frontal lobe in the ventral part + + + align:start position:0% +in the frontal lobe in the ventral part +and you can see here in these more + + align:start position:0% +and you can see here in these more + + + align:start position:0% +and you can see here in these more +recently done + + align:start position:0% +recently done + + + align:start position:0% +recently done +these are about well i don't know 20 + + align:start position:0% +these are about well i don't know 20 + + + align:start position:0% +these are about well i don't know 20 +years old now + + align:start position:0% +years old now + + + align:start position:0% +years old now +when functional imaging first began + + align:start position:0% +when functional imaging first began + + + align:start position:0% +when functional imaging first began +to become popular + + align:start position:0% + + + + align:start position:0% + +and + + align:start position:0% +and + + + align:start position:0% +and +marcus directly was one of the universe + + align:start position:0% +marcus directly was one of the universe + + + align:start position:0% +marcus directly was one of the universe +universe st louis university + + align:start position:0% +universe st louis university + + + align:start position:0% +universe st louis university +was one of the people that pioneered in + + align:start position:0% +was one of the people that pioneered in + + + align:start position:0% +was one of the people that pioneered in +this area + + align:start position:0% +this area + + + align:start position:0% +this area +he noted that + + align:start position:0% + + + + align:start position:0% + +when a person + + align:start position:0% + + + + align:start position:0% + +spoke + + align:start position:0% +spoke + + + align:start position:0% +spoke +and here he had them generating verbs + + align:start position:0% +and here he had them generating verbs + + + align:start position:0% +and here he had them generating verbs +this area became more showed more + + align:start position:0% +this area became more showed more + + + align:start position:0% +this area became more showed more +tissue oxygenation or blood flow + + align:start position:0% +tissue oxygenation or blood flow + + + align:start position:0% +tissue oxygenation or blood flow +different methods for imaging + + align:start position:0% +different methods for imaging + + + align:start position:0% +different methods for imaging +based on one of those two things + + align:start position:0% +based on one of those two things + + + align:start position:0% +based on one of those two things +the imaging people will say it's + + align:start position:0% +the imaging people will say it's + + + align:start position:0% +the imaging people will say it's +activated this area in the frontal lobe + + align:start position:0% +activated this area in the frontal lobe + + + align:start position:0% +activated this area in the frontal lobe +on the left side the lower part of the + + align:start position:0% +on the left side the lower part of the + + + align:start position:0% +on the left side the lower part of the +left side + + align:start position:0% +left side + + + align:start position:0% +left side +well that was the area where boca found + + align:start position:0% +well that was the area where boca found + + + align:start position:0% +well that was the area where boca found +the damage to be centered there was + + align:start position:0% +the damage to be centered there was + + + align:start position:0% +the damage to be centered there was +variability in patient patient but there + + align:start position:0% +variability in patient patient but there + + + align:start position:0% +variability in patient patient but there +was some + + align:start position:0% +was some + + + align:start position:0% +was some +that was the area that was consistently + + align:start position:0% +that was the area that was consistently + + + align:start position:0% +that was the area that was consistently +damaged in the people with + + align:start position:0% +damaged in the people with + + + align:start position:0% +damaged in the people with +aphasia that's the word for the lack of + + align:start position:0% +aphasia that's the word for the lack of + + + align:start position:0% +aphasia that's the word for the lack of +speech after brain damage + + align:start position:0% +speech after brain damage + + + align:start position:0% +speech after brain damage +aphasia or dysphagia + + align:start position:0% + + + + align:start position:0% + +you can see that other aspects of + + align:start position:0% +you can see that other aspects of + + + align:start position:0% +you can see that other aspects of +language were differently localized + + align:start position:0% +language were differently localized + + + align:start position:0% +language were differently localized +hearing + + align:start position:0% +hearing + + + align:start position:0% +hearing +verbs + + align:start position:0% +verbs + + + align:start position:0% +verbs +activated + + align:start position:0% +activated + + + align:start position:0% +activated +an area there that we know to be + + align:start position:0% +an area there that we know to be + + + align:start position:0% +an area there that we know to be +auditory in function + + align:start position:0% +auditory in function + + + align:start position:0% +auditory in function +here + + align:start position:0% + + + + align:start position:0% + +i think this one stopped working there + + align:start position:0% +i think this one stopped working there + + + align:start position:0% +i think this one stopped working there +just + + align:start position:0% +just + + + align:start position:0% +just +here + + align:start position:0% + + + + align:start position:0% + +okay so it's not going to work + + align:start position:0% +okay so it's not going to work + + + align:start position:0% +okay so it's not going to work +just seeing the words not hearing them + + align:start position:0% +just seeing the words not hearing them + + + align:start position:0% +just seeing the words not hearing them +in the upper right there activated an + + align:start position:0% +in the upper right there activated an + + + align:start position:0% +in the upper right there activated an +area we now know to be concerned with + + align:start position:0% +area we now know to be concerned with + + + align:start position:0% +area we now know to be concerned with +vision + + align:start position:0% + + + + align:start position:0% + +and reading + + align:start position:0% +and reading + + + align:start position:0% +and reading +of course involves not only seeing the + + align:start position:0% +of course involves not only seeing the + + + align:start position:0% +of course involves not only seeing the +words but + + align:start position:0% +words but + + + align:start position:0% +words but +also + + align:start position:0% +also + + + align:start position:0% +also +uttering them speaking them + + align:start position:0% +uttering them speaking them + + + align:start position:0% +uttering them speaking them +and that activated sensory motor cortex + + align:start position:0% +and that activated sensory motor cortex + + + align:start position:0% +and that activated sensory motor cortex +now you say well if he's seeing the + + align:start position:0% +now you say well if he's seeing the + + + align:start position:0% +now you say well if he's seeing the +words why isn't it activating the visual + + align:start position:0% +words why isn't it activating the visual + + + align:start position:0% +words why isn't it activating the visual +system also is in the upper right there + + align:start position:0% +system also is in the upper right there + + + align:start position:0% +system also is in the upper right there +and that points out something that's + + align:start position:0% +and that points out something that's + + + align:start position:0% +and that points out something that's +very important about these imaging that + + align:start position:0% +very important about these imaging that + + + align:start position:0% +very important about these imaging that +they're always using thresholding + + align:start position:0% +they're always using thresholding + + + align:start position:0% +they're always using thresholding +techniques okay so the engineers and the + + align:start position:0% +techniques okay so the engineers and the + + + align:start position:0% +techniques okay so the engineers and the +mathematicians + + align:start position:0% +mathematicians + + + align:start position:0% +mathematicians +are in between the data + + align:start position:0% +are in between the data + + + align:start position:0% +are in between the data +and + + align:start position:0% +and + + + align:start position:0% +and +the people that are getting the data and + + align:start position:0% +the people that are getting the data and + + + align:start position:0% +the people that are getting the data and +interpreting it + + align:start position:0% +interpreting it + + + align:start position:0% +interpreting it +okay and they have to choose a cut off + + align:start position:0% +okay and they have to choose a cut off + + + align:start position:0% +okay and they have to choose a cut off +so all it means is the + + align:start position:0% +so all it means is the + + + align:start position:0% +so all it means is the +area with the greatest tissue + + align:start position:0% +area with the greatest tissue + + + align:start position:0% +area with the greatest tissue +oxygenation or the greatest blood blood + + align:start position:0% +oxygenation or the greatest blood blood + + + align:start position:0% +oxygenation or the greatest blood blood +flow + + align:start position:0% +flow + + + align:start position:0% +flow +or sometimes it's even a temperature + + align:start position:0% +or sometimes it's even a temperature + + + align:start position:0% +or sometimes it's even a temperature +change they're looking at + + align:start position:0% +change they're looking at + + + align:start position:0% +change they're looking at +that's what they're showing + + align:start position:0% +that's what they're showing + + + align:start position:0% +that's what they're showing +okay so you're not seeing all the data + + align:start position:0% +okay so you're not seeing all the data + + + align:start position:0% +okay so you're not seeing all the data +in these imaging pictures + + align:start position:0% + + + + align:start position:0% + +and that method + + align:start position:0% +and that method + + + align:start position:0% +and that method +often is not discussed adequately and + + align:start position:0% +often is not discussed adequately and + + + align:start position:0% +often is not discussed adequately and +there's not enough variety in my view of + + align:start position:0% +there's not enough variety in my view of + + + align:start position:0% +there's not enough variety in my view of +the methods being used + + align:start position:0% + + + + align:start position:0% + +let's talk about another discovery that + + align:start position:0% +let's talk about another discovery that + + + align:start position:0% +let's talk about another discovery that +came not that long afterwards + + align:start position:0% +came not that long afterwards + + + align:start position:0% +came not that long afterwards +the discovery of the motor cortex + + align:start position:0% +the discovery of the motor cortex + + + align:start position:0% +the discovery of the motor cortex +fridge and hidsick were two german + + align:start position:0% +fridge and hidsick were two german + + + align:start position:0% +fridge and hidsick were two german +physiologists + + align:start position:0% +physiologists + + + align:start position:0% +physiologists +who + + align:start position:0% +who + + + align:start position:0% +who +did studies of dogs initially using + + align:start position:0% +did studies of dogs initially using + + + align:start position:0% +did studies of dogs initially using +what at that time was fairly new + + align:start position:0% +what at that time was fairly new + + + align:start position:0% +what at that time was fairly new +newly + + align:start position:0% +newly + + + align:start position:0% +newly +developing methods for studying the + + align:start position:0% +developing methods for studying the + + + align:start position:0% +developing methods for studying the +brain electrical stimulation + + align:start position:0% +brain electrical stimulation + + + align:start position:0% +brain electrical stimulation +and they systematically studied + + align:start position:0% +and they systematically studied + + + align:start position:0% +and they systematically studied +the exposed surface of dog brains + + align:start position:0% + + + + align:start position:0% + +trying to put out of our minds for the + + align:start position:0% +trying to put out of our minds for the + + + align:start position:0% +trying to put out of our minds for the +moment that they + + align:start position:0% +moment that they + + + align:start position:0% +moment that they +didn't have anesthetics at that time + + align:start position:0% +didn't have anesthetics at that time + + + align:start position:0% +didn't have anesthetics at that time +they found that they could get movements + + align:start position:0% +they found that they could get movements + + + align:start position:0% +they found that they could get movements +from many different parts of the brain + + align:start position:0% +from many different parts of the brain + + + align:start position:0% +from many different parts of the brain +but there was one region + + align:start position:0% +but there was one region + + + align:start position:0% +but there was one region +where they could get the movement at the + + align:start position:0% +where they could get the movement at the + + + align:start position:0% +where they could get the movement at the +lowest thresholds + + align:start position:0% +lowest thresholds + + + align:start position:0% +lowest thresholds +the least amount of current and they + + align:start position:0% +the least amount of current and they + + + align:start position:0% +the least amount of current and they +call that the motor cortex + + align:start position:0% +call that the motor cortex + + + align:start position:0% +call that the motor cortex +and they found that when they stimulated + + align:start position:0% +and they found that when they stimulated + + + align:start position:0% +and they found that when they stimulated +different parts of the strip of tissue + + align:start position:0% +different parts of the strip of tissue + + + align:start position:0% +different parts of the strip of tissue +different parts of the body moved and it + + align:start position:0% +different parts of the body moved and it + + + align:start position:0% +different parts of the body moved and it +was very systematic + + align:start position:0% + + + + align:start position:0% + +in the uh + + align:start position:0% + + + + align:start position:0% + +the area they were talking about + + align:start position:0% + + + + align:start position:0% + +is called in this picture of the human + + align:start position:0% +is called in this picture of the human + + + align:start position:0% +is called in this picture of the human +brain primary motor cortex + + align:start position:0% + + + + align:start position:0% + +okay the strip of cortex + + align:start position:0% + + + + align:start position:0% + +right in front of the central fissure + + align:start position:0% +right in front of the central fissure + + + align:start position:0% +right in front of the central fissure +okay other parts that are called + + align:start position:0% +okay other parts that are called + + + align:start position:0% +okay other parts that are called +pre-motor + + align:start position:0% +pre-motor + + + align:start position:0% +pre-motor +where you also get movements but they're + + align:start position:0% +where you also get movements but they're + + + align:start position:0% +where you also get movements but they're +a little involving larger parts of the + + align:start position:0% +a little involving larger parts of the + + + align:start position:0% +a little involving larger parts of the +body more organized movements + + align:start position:0% + + + + align:start position:0% + +and that the topography of that + + align:start position:0% +and that the topography of that + + + align:start position:0% +and that the topography of that +system is expressed in this kind of + + align:start position:0% +system is expressed in this kind of + + + align:start position:0% +system is expressed in this kind of +there's many different versions of that + + align:start position:0% +there's many different versions of that + + + align:start position:0% +there's many different versions of that +this is one for the motor cortex + + align:start position:0% +this is one for the motor cortex + + + align:start position:0% +this is one for the motor cortex +the term homunculus means little man + + align:start position:0% +the term homunculus means little man + + + align:start position:0% +the term homunculus means little man +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so this is the little man in the head + + align:start position:0% + + + + align:start position:0% + +so there you see the map + + align:start position:0% +so there you see the map + + + align:start position:0% +so there you see the map +of movements + + align:start position:0% +of movements + + + align:start position:0% +of movements +laid out in a + + align:start position:0% +laid out in a + + + align:start position:0% +laid out in a +more or less frontal section of the + + align:start position:0% +more or less frontal section of the + + + align:start position:0% +more or less frontal section of the +human brain that goes through + + align:start position:0% +human brain that goes through + + + align:start position:0% +human brain that goes through +cuts through that precentral gyrus in + + align:start position:0% +cuts through that precentral gyrus in + + + align:start position:0% +cuts through that precentral gyrus in +front of that the central fissure in the + + align:start position:0% +front of that the central fissure in the + + + align:start position:0% +front of that the central fissure in the +brain + + align:start position:0% +brain + + + align:start position:0% +brain +and they're simply depicting + + align:start position:0% +and they're simply depicting + + + align:start position:0% +and they're simply depicting +both with words and then with pictures + + align:start position:0% +both with words and then with pictures + + + align:start position:0% +both with words and then with pictures +how + + align:start position:0% + + + + align:start position:0% + +different parts of the body are will + + align:start position:0% +different parts of the body are will + + + align:start position:0% +different parts of the body are will +move when you stimulate different parts + + align:start position:0% +move when you stimulate different parts + + + align:start position:0% +move when you stimulate different parts +and you find a much greater + + align:start position:0% +and you find a much greater + + + align:start position:0% +and you find a much greater +representation much more tissue + + align:start position:0% +representation much more tissue + + + align:start position:0% +representation much more tissue +representing say the hands + + align:start position:0% +representing say the hands + + + align:start position:0% +representing say the hands +the lips and the tongue + + align:start position:0% +the lips and the tongue + + + align:start position:0% +the lips and the tongue +than other parts of the body + + align:start position:0% + + + + align:start position:0% + +notice in the motor cortex + + align:start position:0% +notice in the motor cortex + + + align:start position:0% +notice in the motor cortex +some things don't appear to be + + align:start position:0% +some things don't appear to be + + + align:start position:0% +some things don't appear to be +represented at all + + align:start position:0% + + + + align:start position:0% + +this is another + + align:start position:0% +this is another + + + align:start position:0% +this is another +a picture of the area + + align:start position:0% +a picture of the area + + + align:start position:0% +a picture of the area +the gyrus just behind the motor cortex + + align:start position:0% +the gyrus just behind the motor cortex + + + align:start position:0% +the gyrus just behind the motor cortex +which responds to sensory input now that + + align:start position:0% +which responds to sensory input now that + + + align:start position:0% +which responds to sensory input now that +was discovered later if you stimulate + + align:start position:0% +was discovered later if you stimulate + + + align:start position:0% +was discovered later if you stimulate +the surface of different parts of the + + align:start position:0% +the surface of different parts of the + + + align:start position:0% +the surface of different parts of the +body you will activate + + align:start position:0% +body you will activate + + + align:start position:0% +body you will activate +certain areas much more than others in + + align:start position:0% +certain areas much more than others in + + + align:start position:0% +certain areas much more than others in +the brain + + align:start position:0% +the brain + + + align:start position:0% +the brain +and you'll see that it pretty much + + align:start position:0% +and you'll see that it pretty much + + + align:start position:0% +and you'll see that it pretty much +matches the motor cortex right in front + + align:start position:0% +matches the motor cortex right in front + + + align:start position:0% +matches the motor cortex right in front +of it again much larger + + align:start position:0% +of it again much larger + + + align:start position:0% +of it again much larger +area representing lips + + align:start position:0% +area representing lips + + + align:start position:0% +area representing lips +and face and fingers and hands + + align:start position:0% +and face and fingers and hands + + + align:start position:0% +and face and fingers and hands +than other parts + + align:start position:0% + + + + align:start position:0% + +and you always find the face + + align:start position:0% +and you always find the face + + + align:start position:0% +and you always find the face +tongue + + align:start position:0% +tongue + + + align:start position:0% +tongue +and throat + + align:start position:0% +and throat + + + align:start position:0% +and throat +located more ventrally as you go up on + + align:start position:0% +located more ventrally as you go up on + + + align:start position:0% +located more ventrally as you go up on +top + + align:start position:0% +top + + + align:start position:0% +top +you find + + align:start position:0% +you find + + + align:start position:0% +you find +first the hands + + align:start position:0% +first the hands + + + align:start position:0% +first the hands +and then + + align:start position:0% +and then + + + align:start position:0% +and then +more parts of the body and the feet + + align:start position:0% + + + + align:start position:0% + +there's another way they represent it + + align:start position:0% +there's another way they represent it + + + align:start position:0% +there's another way they represent it +you get all varieties of these pictures + + align:start position:0% + + + + align:start position:0% + +this is another common way to show the + + align:start position:0% +this is another common way to show the + + + align:start position:0% +this is another common way to show the +homunculus to emphasize the + + align:start position:0% +homunculus to emphasize the + + + align:start position:0% +homunculus to emphasize the +distortions + + align:start position:0% +distortions + + + align:start position:0% +distortions +now remember + + align:start position:0% + + + + align:start position:0% + +if you actually look at the tissue + + align:start position:0% +if you actually look at the tissue + + + align:start position:0% +if you actually look at the tissue +you're not + + align:start position:0% +you're not + + + align:start position:0% +you're not +seeing anything like that this is just a + + align:start position:0% +seeing anything like that this is just a + + + align:start position:0% +seeing anything like that this is just a +way to represent it + + align:start position:0% +way to represent it + + + align:start position:0% +way to represent it +okay + + align:start position:0% +okay + + + align:start position:0% +okay +way to represent + + align:start position:0% +way to represent + + + align:start position:0% +way to represent +something when we're talking about + + align:start position:0% +something when we're talking about + + + align:start position:0% +something when we're talking about +sensory cortex we call the relative + + align:start position:0% +sensory cortex we call the relative + + + align:start position:0% +sensory cortex we call the relative +magnification + + align:start position:0% +magnification + + + align:start position:0% +magnification +of the sensory surfaces + + align:start position:0% +of the sensory surfaces + + + align:start position:0% +of the sensory surfaces +okay + + align:start position:0% +okay + + + align:start position:0% +okay +but there's a corresponding concept for + + align:start position:0% +but there's a corresponding concept for + + + align:start position:0% +but there's a corresponding concept for +the motor + + align:start position:0% +the motor + + + align:start position:0% +the motor +here + + align:start position:0% + + + + align:start position:0% + +there's more there's a greater area of + + align:start position:0% +there's more there's a greater area of + + + align:start position:0% +there's more there's a greater area of +cortex representing + + align:start position:0% +cortex representing + + + align:start position:0% +cortex representing +a square centimeter of your the skin on + + align:start position:0% +a square centimeter of your the skin on + + + align:start position:0% +a square centimeter of your the skin on +your finger than there is the skin on + + align:start position:0% +your finger than there is the skin on + + + align:start position:0% +your finger than there is the skin on +your back + + align:start position:0% +your back + + + align:start position:0% +your back +okay + + align:start position:0% + + + + align:start position:0% + +not if it's sensory area + + align:start position:0% +not if it's sensory area + + + align:start position:0% +not if it's sensory area +it means for the motor cortex that you + + align:start position:0% +it means for the motor cortex that you + + + align:start position:0% +it means for the motor cortex that you +will get a response + + align:start position:0% +will get a response + + + align:start position:0% +will get a response +say of the finger over a bigger area of + + align:start position:0% +say of the finger over a bigger area of + + + align:start position:0% +say of the finger over a bigger area of +cortex then you will get say the twitch + + align:start position:0% +cortex then you will get say the twitch + + + align:start position:0% +cortex then you will get say the twitch +of a muscle in your back + + align:start position:0% +of a muscle in your back + + + align:start position:0% +of a muscle in your back +okay + + align:start position:0% + + + + align:start position:0% + +well + + align:start position:0% +well + + + align:start position:0% +well +shortly after the motor cortex had been + + align:start position:0% +shortly after the motor cortex had been + + + align:start position:0% +shortly after the motor cortex had been +mapped by fritz and hitzig + + align:start position:0% + + + + align:start position:0% + +a german anatomist named bets + + align:start position:0% +a german anatomist named bets + + + align:start position:0% +a german anatomist named bets +was doing separate independent studies + + align:start position:0% +was doing separate independent studies + + + align:start position:0% +was doing separate independent studies +and he noticed a very large + + align:start position:0% +and he noticed a very large + + + align:start position:0% +and he noticed a very large +neuron + + align:start position:0% +neuron + + + align:start position:0% +neuron +was consistently located in one part of + + align:start position:0% +was consistently located in one part of + + + align:start position:0% +was consistently located in one part of +the cortex and it turns out that that + + align:start position:0% +the cortex and it turns out that that + + + align:start position:0% +the cortex and it turns out that that +cortex where this very large pyramidal + + align:start position:0% +cortex where this very large pyramidal + + + align:start position:0% +cortex where this very large pyramidal +cell was located in the fifth layer of + + align:start position:0% +cell was located in the fifth layer of + + + align:start position:0% +cell was located in the fifth layer of +the cortex + + align:start position:0% +the cortex + + + align:start position:0% +the cortex +was what was in the motor cortex + + align:start position:0% +was what was in the motor cortex + + + align:start position:0% +was what was in the motor cortex +and that's remained true uh + + align:start position:0% +and that's remained true uh + + + align:start position:0% +and that's remained true uh +ever since that time it was never + + align:start position:0% +ever since that time it was never + + + align:start position:0% +ever since that time it was never +it's it was a finding that was very real + + align:start position:0% +it's it was a finding that was very real + + + align:start position:0% +it's it was a finding that was very real +and we always find these largest + + align:start position:0% +and we always find these largest + + + align:start position:0% +and we always find these largest +pyramidal cells the largest cells in the + + align:start position:0% +pyramidal cells the largest cells in the + + + align:start position:0% +pyramidal cells the largest cells in the +neocortex + + align:start position:0% +neocortex + + + align:start position:0% +neocortex +located in the + + align:start position:0% +located in the + + + align:start position:0% +located in the +precentral gyrus the motor cortex + + align:start position:0% +precentral gyrus the motor cortex + + + align:start position:0% +precentral gyrus the motor cortex +okay we find them there in rats we find + + align:start position:0% +okay we find them there in rats we find + + + align:start position:0% +okay we find them there in rats we find +them there in dogs we find them there in + + align:start position:0% +them there in dogs we find them there in + + + align:start position:0% +them there in dogs we find them there in +humans + + align:start position:0% +humans + + + align:start position:0% +humans +okay there was a question over here + + align:start position:0% + + + + align:start position:0% + +very good question does the does the + + align:start position:0% +very good question does the does the + + + align:start position:0% +very good question does the does the +size correspond to sensitivity well + + align:start position:0% +size correspond to sensitivity well + + + align:start position:0% +size correspond to sensitivity well +in fact there's a very good correlation + + align:start position:0% +in fact there's a very good correlation + + + align:start position:0% +in fact there's a very good correlation +between sensory acuity and the area of + + align:start position:0% +between sensory acuity and the area of + + + align:start position:0% +between sensory acuity and the area of +cortex + + align:start position:0% +cortex + + + align:start position:0% +cortex +concerned with that part of the body + + align:start position:0% +concerned with that part of the body + + + align:start position:0% +concerned with that part of the body +okay now how do you measure sensory + + align:start position:0% +okay now how do you measure sensory + + + align:start position:0% +okay now how do you measure sensory +acuity + + align:start position:0% +acuity + + + align:start position:0% +acuity +well one + + align:start position:0% +well one + + + align:start position:0% +well one +method would be what's called two-point + + align:start position:0% +method would be what's called two-point + + + align:start position:0% +method would be what's called two-point +discrimination you take you know two + + align:start position:0% +discrimination you take you know two + + + align:start position:0% +discrimination you take you know two +little needles + + align:start position:0% +little needles + + + align:start position:0% +little needles +and you + + align:start position:0% +and you + + + align:start position:0% +and you +if you put them very close together and + + align:start position:0% +if you put them very close together and + + + align:start position:0% +if you put them very close together and +touch the back of my hand + + align:start position:0% +touch the back of my hand + + + align:start position:0% +touch the back of my hand +they will i won't be able to tell that + + align:start position:0% +they will i won't be able to tell that + + + align:start position:0% +they will i won't be able to tell that +there's two but if you make them further + + align:start position:0% +there's two but if you make them further + + + align:start position:0% +there's two but if you make them further +and further apart + + align:start position:0% +and further apart + + + align:start position:0% +and further apart +you know you'll reach a point where i'll + + align:start position:0% +you know you'll reach a point where i'll + + + align:start position:0% +you know you'll reach a point where i'll +say there's two of them + + align:start position:0% +say there's two of them + + + align:start position:0% +say there's two of them +that's two-point discrimination it's a + + align:start position:0% +that's two-point discrimination it's a + + + align:start position:0% +that's two-point discrimination it's a +measure of acuity + + align:start position:0% +measure of acuity + + + align:start position:0% +measure of acuity +well your you will be able to tell + + align:start position:0% +well your you will be able to tell + + + align:start position:0% +well your you will be able to tell +there's two and those two needles are + + align:start position:0% +there's two and those two needles are + + + align:start position:0% +there's two and those two needles are +much closer to each other on the tip of + + align:start position:0% +much closer to each other on the tip of + + + align:start position:0% +much closer to each other on the tip of +your finger + + align:start position:0% +your finger + + + align:start position:0% +your finger +than the back of your hand + + align:start position:0% +than the back of your hand + + + align:start position:0% +than the back of your hand +and either of those will you'll have + + align:start position:0% +and either of those will you'll have + + + align:start position:0% +and either of those will you'll have +much higher acuity than say on the thigh + + align:start position:0% +much higher acuity than say on the thigh + + + align:start position:0% +much higher acuity than say on the thigh +on the back + + align:start position:0% +on the back + + + align:start position:0% +on the back +and that we use that method as a measure + + align:start position:0% +and that we use that method as a measure + + + align:start position:0% +and that we use that method as a measure +of acuity and the correspondence to the + + align:start position:0% +of acuity and the correspondence to the + + + align:start position:0% +of acuity and the correspondence to the +homunculus + + align:start position:0% +homunculus + + + align:start position:0% +homunculus +is very good + + align:start position:0% +is very good + + + align:start position:0% +is very good +yes + + align:start position:0% + + + + align:start position:0% + +does the tissue look different + + align:start position:0% +does the tissue look different + + + align:start position:0% +does the tissue look different +no it basically looks the same + + align:start position:0% +no it basically looks the same + + + align:start position:0% +no it basically looks the same +uh throughout but + + align:start position:0% +uh throughout but + + + align:start position:0% +uh throughout but +it's very interesting question because + + align:start position:0% + + + + align:start position:0% + +the relative growth of brain does affect + + align:start position:0% +the relative growth of brain does affect + + + align:start position:0% +the relative growth of brain does affect +the shape of the gyri the way it folds + + align:start position:0% +the shape of the gyri the way it folds + + + align:start position:0% +the shape of the gyri the way it folds +and uh + + align:start position:0% + + + + align:start position:0% + +in animals that have developed large + + align:start position:0% +in animals that have developed large + + + align:start position:0% +in animals that have developed large +representation of certain parts of their + + align:start position:0% +representation of certain parts of their + + + align:start position:0% +representation of certain parts of their +body sometimes they develop separate + + align:start position:0% +body sometimes they develop separate + + + align:start position:0% +body sometimes they develop separate +gyry for each part like the raccoon's + + align:start position:0% +gyry for each part like the raccoon's + + + align:start position:0% +gyry for each part like the raccoon's +hand their separate diary for each + + align:start position:0% +hand their separate diary for each + + + align:start position:0% +hand their separate diary for each +finger he also has a large magnification + + align:start position:0% +finger he also has a large magnification + + + align:start position:0% +finger he also has a large magnification +of the representation of his fingers + + align:start position:0% +of the representation of his fingers + + + align:start position:0% +of the representation of his fingers +yes + + align:start position:0% + + + + align:start position:0% + +then why + + align:start position:0% + + + + align:start position:0% + +that's very good question okay why are + + align:start position:0% +that's very good question okay why are + + + align:start position:0% +that's very good question okay why are +the genitals so small in the picture + + align:start position:0% +the genitals so small in the picture + + + align:start position:0% +the genitals so small in the picture +well + + align:start position:0% +well + + + align:start position:0% +well +in fact our two-point discrimination + + align:start position:0% +in fact our two-point discrimination + + + align:start position:0% +in fact our two-point discrimination +the the same kind of sensory ability we + + align:start position:0% +the the same kind of sensory ability we + + + align:start position:0% +the the same kind of sensory ability we +measure in fingers or hands + + align:start position:0% +measure in fingers or hands + + + align:start position:0% +measure in fingers or hands +are not that good + + align:start position:0% +are not that good + + + align:start position:0% +are not that good +genitals + + align:start position:0% +genitals + + + align:start position:0% +genitals +but they're very sensitive because + + align:start position:0% +but they're very sensitive because + + + align:start position:0% +but they're very sensitive because +there's another representation + + align:start position:0% +there's another representation + + + align:start position:0% +there's another representation +for these areas in what in an area more + + align:start position:0% +for these areas in what in an area more + + + align:start position:0% +for these areas in what in an area more +concerned with emotion and motivation + + align:start position:0% +concerned with emotion and motivation + + + align:start position:0% +concerned with emotion and motivation +limbic system okay + + align:start position:0% +limbic system okay + + + align:start position:0% +limbic system okay +that's separate from these sensory areas + + align:start position:0% +that's separate from these sensory areas + + + align:start position:0% +that's separate from these sensory areas +okay + + align:start position:0% +okay + + + align:start position:0% +okay +thank you for giving me an opportunity + + align:start position:0% +thank you for giving me an opportunity + + + align:start position:0% +thank you for giving me an opportunity +to introduce the limbic system so early + + align:start position:0% +to introduce the limbic system so early + + + align:start position:0% +to introduce the limbic system so early +in the class yes + + align:start position:0% + + + + align:start position:0% + +say that again + + align:start position:0% + + + + align:start position:0% + +there are some differences between males + + align:start position:0% +there are some differences between males + + + align:start position:0% +there are some differences between males +and females but not in these kinds of + + align:start position:0% +and females but not in these kinds of + + + align:start position:0% +and females but not in these kinds of +things except the real the size of + + align:start position:0% +things except the real the size of + + + align:start position:0% +things except the real the size of +the brain tends to correspond to body + + align:start position:0% +the brain tends to correspond to body + + + align:start position:0% +the brain tends to correspond to body +weight there's a very good correlation + + align:start position:0% +weight there's a very good correlation + + + align:start position:0% +weight there's a very good correlation +so male brains tend to be a little + + align:start position:0% +so male brains tend to be a little + + + align:start position:0% +so male brains tend to be a little +bigger but only because of the + + align:start position:0% +bigger but only because of the + + + align:start position:0% +bigger but only because of the +correlation with body size and body + + align:start position:0% +correlation with body size and body + + + align:start position:0% +correlation with body size and body +weight and size + + align:start position:0% +weight and size + + + align:start position:0% +weight and size +okay + + align:start position:0% +okay + + + align:start position:0% +okay +there are some other sex differences in + + align:start position:0% +there are some other sex differences in + + + align:start position:0% +there are some other sex differences in +the brain + + align:start position:0% +the brain + + + align:start position:0% +the brain +that i talk about more of the second + + align:start position:0% +that i talk about more of the second + + + align:start position:0% +that i talk about more of the second +term but we will you will read a little + + align:start position:0% +term but we will you will read a little + + + align:start position:0% +term but we will you will read a little +bit about that + + align:start position:0% +bit about that + + + align:start position:0% +bit about that +later in the class + + align:start position:0% +later in the class + + + align:start position:0% +later in the class +these are all very good questions + + align:start position:0% + + + + align:start position:0% + +okay one more + + align:start position:0% +okay one more + + + align:start position:0% +okay one more +of the early localization is carl + + align:start position:0% +of the early localization is carl + + + align:start position:0% +of the early localization is carl +wernicke who was the most modern of + + align:start position:0% +wernicke who was the most modern of + + + align:start position:0% +wernicke who was the most modern of +these people in the way he thought about + + align:start position:0% +these people in the way he thought about + + + align:start position:0% +these people in the way he thought about +brain function + + align:start position:0% +brain function + + + align:start position:0% +brain function +wernicke + + align:start position:0% +wernicke + + + align:start position:0% +wernicke +whose + + align:start position:0% +whose + + + align:start position:0% +whose +theory was taken up again + + align:start position:0% +theory was taken up again + + + align:start position:0% +theory was taken up again +in the last century + + align:start position:0% +in the last century + + + align:start position:0% +in the last century +by + + align:start position:0% +by + + + align:start position:0% +by +norman geschwind so we now call this the + + align:start position:0% +norman geschwind so we now call this the + + + align:start position:0% +norman geschwind so we now call this the +wernicke geshwant connections model of + + align:start position:0% +wernicke geshwant connections model of + + + align:start position:0% +wernicke geshwant connections model of +speech + + align:start position:0% +speech + + + align:start position:0% +speech +yeshuan was really the founder of the + + align:start position:0% +yeshuan was really the founder of the + + + align:start position:0% +yeshuan was really the founder of the +boston behavioral neurologist school + + align:start position:0% +boston behavioral neurologist school + + + align:start position:0% +boston behavioral neurologist school +and his students still are very + + align:start position:0% +and his students still are very + + + align:start position:0% +and his students still are very +prominent in behavioral neurology + + align:start position:0% + + + + align:start position:0% + +he used to teach with me here at mit i'm + + align:start position:0% +he used to teach with me here at mit i'm + + + align:start position:0% +he used to teach with me here at mit i'm +proud to say + + align:start position:0% +proud to say + + + align:start position:0% +proud to say +but he died a number of years ago + + align:start position:0% +but he died a number of years ago + + + align:start position:0% +but he died a number of years ago +okay so here is broca's area + + align:start position:0% +okay so here is broca's area + + + align:start position:0% +okay so here is broca's area +that we know is concerned with speech + + align:start position:0% +that we know is concerned with speech + + + align:start position:0% +that we know is concerned with speech +output + + align:start position:0% +output + + + align:start position:0% +output +here's the auditory + + align:start position:0% +here's the auditory + + + align:start position:0% +here's the auditory +area shown in purple there + + align:start position:0% +area shown in purple there + + + align:start position:0% +area shown in purple there +here's visual cortex here + + align:start position:0% + + + + align:start position:0% + +wernicke discovered that there was an + + align:start position:0% +wernicke discovered that there was an + + + align:start position:0% +wernicke discovered that there was an +area + + align:start position:0% +area + + + align:start position:0% +area +in the posterior dorsal temporal region + + align:start position:0% +in the posterior dorsal temporal region + + + align:start position:0% +in the posterior dorsal temporal region +of the brain of the left hemisphere in + + align:start position:0% +of the brain of the left hemisphere in + + + align:start position:0% +of the brain of the left hemisphere in +most people that when damaged cause a + + align:start position:0% +most people that when damaged cause a + + + align:start position:0% +most people that when damaged cause a +different kind of disturbance + + align:start position:0% +different kind of disturbance + + + align:start position:0% +different kind of disturbance +of language + + align:start position:0% +of language + + + align:start position:0% +of language +they could still talk + + align:start position:0% +they could still talk + + + align:start position:0% +they could still talk +but they didn't understand + + align:start position:0% + + + + align:start position:0% + +nor could they read + + align:start position:0% + + + + align:start position:0% + +we call that arie wernicke's area + + align:start position:0% +we call that arie wernicke's area + + + align:start position:0% +we call that arie wernicke's area +and + + align:start position:0% +and + + + align:start position:0% +and +wernicke + + align:start position:0% +wernicke + + + align:start position:0% +wernicke +showed + + align:start position:0% +showed + + + align:start position:0% +showed +a a kind of connectionist model of + + align:start position:0% +a a kind of connectionist model of + + + align:start position:0% +a a kind of connectionist model of +speech that is still held to by many + + align:start position:0% +speech that is still held to by many + + + align:start position:0% +speech that is still held to by many +people + + align:start position:0% +people + + + align:start position:0% +people +although there are arguments about it + + align:start position:0% +although there are arguments about it + + + align:start position:0% +although there are arguments about it +so when you hear a word and you hear the + + align:start position:0% +so when you hear a word and you hear the + + + align:start position:0% +so when you hear a word and you hear the +word and then speak it + + align:start position:0% + + + + align:start position:0% + +the input comes into the auditory area + + align:start position:0% +the input comes into the auditory area + + + align:start position:0% +the input comes into the auditory area +of cortex now it comes into subcortical + + align:start position:0% +of cortex now it comes into subcortical + + + align:start position:0% +of cortex now it comes into subcortical +areas first but it does reach the cortex + + align:start position:0% +areas first but it does reach the cortex + + + align:start position:0% +areas first but it does reach the cortex +first in this region + + align:start position:0% +first in this region + + + align:start position:0% +first in this region +the upper part of the temporal lobe + + align:start position:0% +the upper part of the temporal lobe + + + align:start position:0% +the upper part of the temporal lobe +the information he said passes from + + align:start position:0% +the information he said passes from + + + align:start position:0% +the information he said passes from +there + + align:start position:0% +there + + + align:start position:0% +there +to wernicke's area + + align:start position:0% + + + + align:start position:0% + +not necessarily with a single synapse it + + align:start position:0% +not necessarily with a single synapse it + + + align:start position:0% +not necessarily with a single synapse it +might take a couple + + align:start position:0% +might take a couple + + + align:start position:0% +might take a couple +okay and the information then to + + align:start position:0% +okay and the information then to + + + align:start position:0% +okay and the information then to +actually speak the word has to go from + + align:start position:0% +actually speak the word has to go from + + + align:start position:0% +actually speak the word has to go from +there + + align:start position:0% +there + + + align:start position:0% +there +through long accents that go to broca's + + align:start position:0% +through long accents that go to broca's + + + align:start position:0% +through long accents that go to broca's +area and then to the motor cortex + + align:start position:0% +area and then to the motor cortex + + + align:start position:0% +area and then to the motor cortex +that model is and then he said for + + align:start position:0% +that model is and then he said for + + + align:start position:0% +that model is and then he said for +reading + + align:start position:0% +reading + + + align:start position:0% +reading +if you have a written word you see it + + align:start position:0% +if you have a written word you see it + + + align:start position:0% +if you have a written word you see it +and speak the word the information comes + + align:start position:0% +and speak the word the information comes + + + align:start position:0% +and speak the word the information comes +into the visual cortex and has to go + + align:start position:0% +into the visual cortex and has to go + + + align:start position:0% +into the visual cortex and has to go +from there + + align:start position:0% +from there + + + align:start position:0% +from there +to an association area which connects to + + align:start position:0% +to an association area which connects to + + + align:start position:0% +to an association area which connects to +wernicke's area + + align:start position:0% +wernicke's area + + + align:start position:0% +wernicke's area +and then again the rest of it's the same + + align:start position:0% +and then again the rest of it's the same + + + align:start position:0% +and then again the rest of it's the same +goes to broca's area and then to the + + align:start position:0% +goes to broca's area and then to the + + + align:start position:0% +goes to broca's area and then to the +motor cortex okay + + align:start position:0% +motor cortex okay + + + align:start position:0% +motor cortex okay +now that model has been supported + + align:start position:0% +now that model has been supported + + + align:start position:0% +now that model has been supported +by a number of lesion studies including + + align:start position:0% +by a number of lesion studies including + + + align:start position:0% +by a number of lesion studies including +studies where people have suffered a + + align:start position:0% +studies where people have suffered a + + + align:start position:0% +studies where people have suffered a +disconnection of one of those pathways + + align:start position:0% +disconnection of one of those pathways + + + align:start position:0% +disconnection of one of those pathways +so for example if people + + align:start position:0% +so for example if people + + + align:start position:0% +so for example if people +lose the connections between the posture + + align:start position:0% +lose the connections between the posture + + + align:start position:0% +lose the connections between the posture +temporal region and the frontal cortex + + align:start position:0% +temporal region and the frontal cortex + + + align:start position:0% +temporal region and the frontal cortex +some + + align:start position:0% +some + + + align:start position:0% +some +brain damage that sever is what we call + + align:start position:0% +brain damage that sever is what we call + + + align:start position:0% +brain damage that sever is what we call +the arcuate fasciculus + + align:start position:0% +the arcuate fasciculus + + + align:start position:0% +the arcuate fasciculus +they can understand speech and they can + + align:start position:0% +they can understand speech and they can + + + align:start position:0% +they can understand speech and they can +speak but when they speak + + align:start position:0% +speak but when they speak + + + align:start position:0% +speak but when they speak +they speak sort of a word salad + + align:start position:0% +they speak sort of a word salad + + + align:start position:0% +they speak sort of a word salad +it doesn't make sense because they don't + + align:start position:0% +it doesn't make sense because they don't + + + align:start position:0% +it doesn't make sense because they don't +have the normal connection between the + + align:start position:0% +have the normal connection between the + + + align:start position:0% +have the normal connection between the +areas comprehension and the area needed + + align:start position:0% +areas comprehension and the area needed + + + align:start position:0% +areas comprehension and the area needed +for + + align:start position:0% +for + + + align:start position:0% +for +producing the utterance utterances + + align:start position:0% + + + + align:start position:0% + +now these people use different words for + + align:start position:0% +now these people use different words for + + + align:start position:0% +now these people use different words for +talking about these than we do + + align:start position:0% +talking about these than we do + + + align:start position:0% +talking about these than we do +especially bronco he talked about this + + align:start position:0% +especially bronco he talked about this + + + align:start position:0% +especially bronco he talked about this +area being sort of a depot of + + align:start position:0% +area being sort of a depot of + + + align:start position:0% +area being sort of a depot of +representations for + + align:start position:0% +representations for + + + align:start position:0% +representations for +speech articulation + + align:start position:0% +speech articulation + + + align:start position:0% +speech articulation +but what happened afterwards was very + + align:start position:0% +but what happened afterwards was very + + + align:start position:0% +but what happened afterwards was very +interesting + + align:start position:0% +interesting + + + align:start position:0% +interesting +now a neurologist every time they had a + + align:start position:0% +now a neurologist every time they had a + + + align:start position:0% +now a neurologist every time they had a +patient + + align:start position:0% +patient + + + align:start position:0% +patient +with a specific brain damage that could + + align:start position:0% +with a specific brain damage that could + + + align:start position:0% +with a specific brain damage that could +be localized they tried to specify the + + align:start position:0% +be localized they tried to specify the + + + align:start position:0% +be localized they tried to specify the +function that was disturbed and these + + align:start position:0% +function that was disturbed and these + + + align:start position:0% +function that was disturbed and these +maps of + + align:start position:0% +maps of + + + align:start position:0% +maps of +functional maps of the brain got more + + align:start position:0% +functional maps of the brain got more + + + align:start position:0% +functional maps of the brain got more +and more elaborate this is a little + + align:start position:0% +and more elaborate this is a little + + + align:start position:0% +and more elaborate this is a little +yellow because i took it out of a + + align:start position:0% +yellow because i took it out of a + + + align:start position:0% +yellow because i took it out of a +book of alexander luria a russian + + align:start position:0% +book of alexander luria a russian + + + align:start position:0% +book of alexander luria a russian +neuropsychologist + + align:start position:0% +neuropsychologist + + + align:start position:0% +neuropsychologist +is the only place i could find this map + + align:start position:0% +is the only place i could find this map + + + align:start position:0% +is the only place i could find this map +it shows many many different details and + + align:start position:0% +it shows many many different details and + + + align:start position:0% +it shows many many different details and +the details + + align:start position:0% +the details + + + align:start position:0% +the details +the functions are sometimes do + + align:start position:0% +the functions are sometimes do + + + align:start position:0% +the functions are sometimes do +correspond to physiological functions + + align:start position:0% +correspond to physiological functions + + + align:start position:0% +correspond to physiological functions +and sometimes they're more psychological + + align:start position:0% +and sometimes they're more psychological + + + align:start position:0% +and sometimes they're more psychological +functions + + align:start position:0% +functions + + + align:start position:0% +functions +and that sometimes raised some + + align:start position:0% +and that sometimes raised some + + + align:start position:0% +and that sometimes raised some +difficulties but what the maps did is + + align:start position:0% +difficulties but what the maps did is + + + align:start position:0% +difficulties but what the maps did is +simply summarize neurological findings + + align:start position:0% +simply summarize neurological findings + + + align:start position:0% +simply summarize neurological findings +so if you knew that + + align:start position:0% +so if you knew that + + + align:start position:0% +so if you knew that +if you look at this map then you'll know + + align:start position:0% +if you look at this map then you'll know + + + align:start position:0% +if you look at this map then you'll know +that okay somebody that suffered the + + align:start position:0% +that okay somebody that suffered the + + + align:start position:0% +that okay somebody that suffered the +damage in that area + + align:start position:0% +damage in that area + + + align:start position:0% +damage in that area +had that + + align:start position:0% +had that + + + align:start position:0% +had that +disturbance of that function one problem + + align:start position:0% +disturbance of that function one problem + + + align:start position:0% +disturbance of that function one problem +is is that lesions are often not very + + align:start position:0% +is is that lesions are often not very + + + align:start position:0% +is is that lesions are often not very +precisely localized they could easily + + align:start position:0% +precisely localized they could easily + + + align:start position:0% +precisely localized they could easily +make mistakes and sometimes the lesions + + align:start position:0% +make mistakes and sometimes the lesions + + + align:start position:0% +make mistakes and sometimes the lesions +would disturb connections between areas + + align:start position:0% +would disturb connections between areas + + + align:start position:0% +would disturb connections between areas +and not just the + + align:start position:0% +and not just the + + + align:start position:0% +and not just the +the cells in that region + + align:start position:0% +the cells in that region + + + align:start position:0% +the cells in that region +and by the time the first textbook in + + align:start position:0% +and by the time the first textbook in + + + align:start position:0% +and by the time the first textbook in +physiological psychology came out + + align:start position:0% +physiological psychology came out + + + align:start position:0% +physiological psychology came out +that's the + + align:start position:0% +that's the + + + align:start position:0% +that's the +word that was used for the field that + + align:start position:0% +word that was used for the field that + + + align:start position:0% +word that was used for the field that +now we just call neuroscience or + + align:start position:0% +now we just call neuroscience or + + + align:start position:0% +now we just call neuroscience or +behavioral + + align:start position:0% + + + + align:start position:0% + +neuroscience was a book by morgan and + + align:start position:0% +neuroscience was a book by morgan and + + + align:start position:0% +neuroscience was a book by morgan and +stellar it came out in 1950 their maps + + align:start position:0% +stellar it came out in 1950 their maps + + + align:start position:0% +stellar it came out in 1950 their maps +were much much simpler than the kleist + + align:start position:0% +were much much simpler than the kleist + + + align:start position:0% +were much much simpler than the kleist +map so just between 1935 and 1950 there + + align:start position:0% +map so just between 1935 and 1950 there + + + align:start position:0% +map so just between 1935 and 1950 there +was this regress people became more + + align:start position:0% +was this regress people became more + + + align:start position:0% +was this regress people became more +critical + + align:start position:0% +critical + + + align:start position:0% +critical +and weren't so willing to accept + + align:start position:0% +and weren't so willing to accept + + + align:start position:0% +and weren't so willing to accept +these localizations + + align:start position:0% +these localizations + + + align:start position:0% +these localizations +because + + align:start position:0% +because + + + align:start position:0% +because +by that time many contradictions had + + align:start position:0% +by that time many contradictions had + + + align:start position:0% +by that time many contradictions had +appeared in the literature so morgan and + + align:start position:0% +appeared in the literature so morgan and + + + align:start position:0% +appeared in the literature so morgan and +stella weren't they felt that if you + + align:start position:0% +stella weren't they felt that if you + + + align:start position:0% +stella weren't they felt that if you +didn't do precise experiments with many + + align:start position:0% +didn't do precise experiments with many + + + align:start position:0% +didn't do precise experiments with many +cases especially if it were backed up by + + align:start position:0% +cases especially if it were backed up by + + + align:start position:0% +cases especially if it were backed up by +animal studies you couldn't really + + align:start position:0% +animal studies you couldn't really + + + align:start position:0% +animal studies you couldn't really +believe it + + align:start position:0% + + + + align:start position:0% + +okay now next time we're going to deal + + align:start position:0% +okay now next time we're going to deal + + + align:start position:0% +okay now next time we're going to deal +with this issue + + align:start position:0% +with this issue + + + align:start position:0% +with this issue +how can you carve up the soul like this + + align:start position:0% +how can you carve up the soul like this + + + align:start position:0% +how can you carve up the soul like this +aren't we unified beings + + align:start position:0% +aren't we unified beings + + + align:start position:0% +aren't we unified beings +are we really just this + + align:start position:0% +are we really just this + + + align:start position:0% +are we really just this +but a collection of functions + + align:start position:0% +but a collection of functions + + + align:start position:0% +but a collection of functions +represented in different parts of the + + align:start position:0% +represented in different parts of the + + + align:start position:0% +represented in different parts of the +brain + + align:start position:0% + + + + align:start position:0% + +read this + + align:start position:0% +read this + + + align:start position:0% +read this +bring your notes to class next time and + + align:start position:0% +bring your notes to class next time and + + + align:start position:0% +bring your notes to class next time and +we'll continue with the discussion then \ No newline at end of file diff --git a/_0LtZx6epcg.txt b/_0LtZx6epcg.txt new file mode 100644 index 0000000000000000000000000000000000000000..b0999e4ead62bdd8cd68b6d875f88aa90d2f909b --- /dev/null +++ b/_0LtZx6epcg.txt @@ -0,0 +1,827 @@ +align:start position:0% + +skin effect describes the tendency for + + align:start position:0% +skin effect describes the tendency for + + + align:start position:0% +skin effect describes the tendency for +highfrequency currents to be near + + align:start position:0% +highfrequency currents to be near + + + align:start position:0% +highfrequency currents to be near +surfaces of + + align:start position:0% + + + + align:start position:0% + +conductors here's the + + align:start position:0% + + + + align:start position:0% + +experiment the section where essentially + + align:start position:0% +experiment the section where essentially + + + align:start position:0% +experiment the section where essentially +onedimensional magnetic diffusion occurs + + align:start position:0% +onedimensional magnetic diffusion occurs + + + align:start position:0% +onedimensional magnetic diffusion occurs +is + + align:start position:0% + + + + align:start position:0% + +here by making the conductor long in the + + align:start position:0% +here by making the conductor long in the + + + align:start position:0% +here by making the conductor long in the +y + + align:start position:0% +y + + + align:start position:0% +y +direction we provide enough length for + + align:start position:0% +direction we provide enough length for + + + align:start position:0% +direction we provide enough length for +the current distribution to become + + align:start position:0% +the current distribution to become + + + align:start position:0% +the current distribution to become +primarily dependent on X over the middle + + align:start position:0% + + + + align:start position:0% + +cross-section to avoid an influence of + + align:start position:0% +cross-section to avoid an influence of + + + align:start position:0% +cross-section to avoid an influence of +the magnetic core on the field + + align:start position:0% +the magnetic core on the field + + + align:start position:0% +the magnetic core on the field +distribution here at the + + align:start position:0% +distribution here at the + + + align:start position:0% +distribution here at the +center we've placed it to one end + + align:start position:0% + + + + align:start position:0% + +this transverse probe can be inserted so + + align:start position:0% +this transverse probe can be inserted so + + + align:start position:0% +this transverse probe can be inserted so +that it samples the vertical magnetic + + align:start position:0% +that it samples the vertical magnetic + + + align:start position:0% +that it samples the vertical magnetic +field intensity over the span of the + + align:start position:0% + + + + align:start position:0% + +conductor the field component normal to + + align:start position:0% +conductor the field component normal to + + + align:start position:0% +conductor the field component normal to +the flat phase is + + align:start position:0% + + + + align:start position:0% + +measured the slit is little more than + + align:start position:0% +measured the slit is little more than + + + align:start position:0% +measured the slit is little more than +large enough enough for the + + align:start position:0% + + + + align:start position:0% + +probe the top Trace is the current in + + align:start position:0% +probe the top Trace is the current in + + + align:start position:0% +probe the top Trace is the current in +the primary of the Transformer the + + align:start position:0% +the primary of the Transformer the + + + align:start position:0% +the primary of the Transformer the +driving + + align:start position:0% +driving + + + align:start position:0% +driving +current the bottom Trace is the probe + + align:start position:0% +current the bottom Trace is the probe + + + align:start position:0% +current the bottom Trace is the probe +signal the magnetic flux + + align:start position:0% +signal the magnetic flux + + + align:start position:0% +signal the magnetic flux +density as we pull the probe + + align:start position:0% +density as we pull the probe + + + align:start position:0% +density as we pull the probe +out we see the field distribution with x + + align:start position:0% + + + + align:start position:0% + +the frequency is 60 + + align:start position:0% +the frequency is 60 + + + align:start position:0% +the frequency is 60 +hertz here we're at 3 cm half the slab + + align:start position:0% +hertz here we're at 3 cm half the slab + + + align:start position:0% +hertz here we're at 3 cm half the slab +thickness it appears that the Decay is + + align:start position:0% +thickness it appears that the Decay is + + + align:start position:0% +thickness it appears that the Decay is +somewhat more rapid than + + align:start position:0% +somewhat more rapid than + + + align:start position:0% +somewhat more rapid than +linear so it looks like the skin depth + + align:start position:0% +linear so it looks like the skin depth + + + align:start position:0% +linear so it looks like the skin depth +at 60 HZ is less than the thickness of + + align:start position:0% +at 60 HZ is less than the thickness of + + + align:start position:0% +at 60 HZ is less than the thickness of +the + + align:start position:0% + + + + align:start position:0% + +aluminum here's a prediction of the + + align:start position:0% +aluminum here's a prediction of the + + + align:start position:0% +aluminum here's a prediction of the +field Decay with distance from the left + + align:start position:0% +field Decay with distance from the left + + + align:start position:0% +field Decay with distance from the left +edge of the conductor + + align:start position:0% +edge of the conductor + + + align:start position:0% +edge of the conductor +this curve is for 60 + + align:start position:0% + + + + align:start position:0% + +hertz in going from 0 to 1 cm here on + + align:start position:0% +hertz in going from 0 to 1 cm here on + + + align:start position:0% +hertz in going from 0 to 1 cm here on +the 60 Herz curve we should see the + + align:start position:0% +the 60 Herz curve we should see the + + + align:start position:0% +the 60 Herz curve we should see the +field Decay by + + align:start position:0% + + + + align:start position:0% + +40% what we measure decays to about 50% + + align:start position:0% +40% what we measure decays to about 50% + + + align:start position:0% +40% what we measure decays to about 50% +of its original value + + align:start position:0% + + + + align:start position:0% + +value remember the skin depth is + + align:start position:0% +value remember the skin depth is + + + align:start position:0% +value remember the skin depth is +inversely proportional to the square + + align:start position:0% +inversely proportional to the square + + + align:start position:0% +inversely proportional to the square +root of the + + align:start position:0% +root of the + + + align:start position:0% +root of the +frequency so if we increase the + + align:start position:0% +frequency so if we increase the + + + align:start position:0% +frequency so if we increase the +frequency to 240 Herz four times the + + align:start position:0% +frequency to 240 Herz four times the + + + align:start position:0% +frequency to 240 Herz four times the +frequency the skin depth is half as much + + align:start position:0% +frequency the skin depth is half as much + + + align:start position:0% +frequency the skin depth is half as much +and the Decay should be more rapid + + align:start position:0% + + + + align:start position:0% + +this is the Decay at 60 + + align:start position:0% + + + + align:start position:0% + +HZ here we're at 1 + + align:start position:0% + + + + align:start position:0% + +cm here we're at 3 + + align:start position:0% + + + + align:start position:0% + +cm now we raise the frequency to 240 + + align:start position:0% + + + + align:start position:0% + +Herz this is the Decay at 240 + + align:start position:0% +Herz this is the Decay at 240 + + + align:start position:0% +Herz this is the Decay at 240 +hertz 1 + + align:start position:0% +hertz 1 + + + align:start position:0% +hertz 1 +cm 3 + + align:start position:0% + + + + align:start position:0% + +cm the Decay at 1 cm and 240 HZ plots + + align:start position:0% +cm the Decay at 1 cm and 240 HZ plots + + + align:start position:0% +cm the Decay at 1 cm and 240 HZ plots +like + + align:start position:0% + + + + align:start position:0% + +this these are additional data + + align:start position:0% +this these are additional data + + + align:start position:0% +this these are additional data +points here's the measured Decay at 2 40 + + align:start position:0% +points here's the measured Decay at 2 40 + + + align:start position:0% +points here's the measured Decay at 2 40 +HZ here at 60 + + align:start position:0% + + + + align:start position:0% + +HZ the discrepancy is probably due to + + align:start position:0% +HZ the discrepancy is probably due to + + + align:start position:0% +HZ the discrepancy is probably due to +the finite length of the aluminum in the + + align:start position:0% +the finite length of the aluminum in the + + + align:start position:0% +the finite length of the aluminum in the +direction of current + + align:start position:0% +direction of current + + + align:start position:0% +direction of current +circulation our one-dimensional Theory + + align:start position:0% +circulation our one-dimensional Theory + + + align:start position:0% +circulation our one-dimensional Theory +strictly applies only where the currents + + align:start position:0% +strictly applies only where the currents + + + align:start position:0% +strictly applies only where the currents +have had sufficient development length + + align:start position:0% + + + + align:start position:0% + +when the skin depth is short compared to + + align:start position:0% +when the skin depth is short compared to + + + align:start position:0% +when the skin depth is short compared to +the conductor thickness the current + + align:start position:0% +the conductor thickness the current + + + align:start position:0% +the conductor thickness the current +distribution takes the form of a + + align:start position:0% +distribution takes the form of a + + + align:start position:0% +distribution takes the form of a +wave we've been observing the decay of + + align:start position:0% +wave we've been observing the decay of + + + align:start position:0% +wave we've been observing the decay of +this + + align:start position:0% +this + + + align:start position:0% +this +wave there's also a phase shift with X + + align:start position:0% +wave there's also a phase shift with X + + + align:start position:0% +wave there's also a phase shift with X +caused by the propagation of this + + align:start position:0% +caused by the propagation of this + + + align:start position:0% +caused by the propagation of this +diffusion wave into the + + align:start position:0% + + + + align:start position:0% + +conductor by looking at the probe signal + + align:start position:0% +conductor by looking at the probe signal + + + align:start position:0% +conductor by looking at the probe signal +on an oscilloscope we can see this phase + + align:start position:0% +on an oscilloscope we can see this phase + + + align:start position:0% +on an oscilloscope we can see this phase +shift as the probe is + + align:start position:0% +shift as the probe is + + + align:start position:0% +shift as the probe is +withdrawn the top Trace is the exitation + + align:start position:0% +withdrawn the top Trace is the exitation + + + align:start position:0% +withdrawn the top Trace is the exitation +current the bottom one probe current + + align:start position:0% +current the bottom one probe current + + + align:start position:0% +current the bottom one probe current +sync to the exitation + + align:start position:0% +sync to the exitation + + + align:start position:0% +sync to the exitation +current the frequency is 240 Herz so as + + align:start position:0% +current the frequency is 240 Herz so as + + + align:start position:0% +current the frequency is 240 Herz so as +the probe is withdrawn the field decays + + align:start position:0% + + + + align:start position:0% + +rapidly to see the phase shift + + align:start position:0% +rapidly to see the phase shift + + + align:start position:0% +rapidly to see the phase shift +associated with the propagation let's + + align:start position:0% +associated with the propagation let's + + + align:start position:0% +associated with the propagation let's +put the probe signal on top of the + + align:start position:0% +put the probe signal on top of the + + + align:start position:0% +put the probe signal on top of the +driving + + align:start position:0% + + + + align:start position:0% + +signal watch the position of a peak in + + align:start position:0% +signal watch the position of a peak in + + + align:start position:0% +signal watch the position of a peak in +the probe signal relative to that of the + + align:start position:0% +the probe signal relative to that of the + + + align:start position:0% +the probe signal relative to that of the +driving current as the probe is + + align:start position:0% + + + + align:start position:0% + +withdrawn as the probe is pulled into + + align:start position:0% +withdrawn as the probe is pulled into + + + align:start position:0% +withdrawn as the probe is pulled into +the conductor it measures a field that + + align:start position:0% +the conductor it measures a field that + + + align:start position:0% +the conductor it measures a field that +is increasingly delayed in phase + + align:start position:0% + + + + align:start position:0% + +the magnitude of the magnetic diffusion + + align:start position:0% +the magnitude of the magnetic diffusion + + + align:start position:0% +the magnitude of the magnetic diffusion +wave decays exponentially into the + + align:start position:0% +wave decays exponentially into the + + + align:start position:0% +wave decays exponentially into the +conductor with a Decay length that is + + align:start position:0% +conductor with a Decay length that is + + + align:start position:0% +conductor with a Decay length that is +the skin + + align:start position:0% + + + + align:start position:0% + +depth the phase shift shows that the + + align:start position:0% +depth the phase shift shows that the + + + align:start position:0% +depth the phase shift shows that the +wave has phases that propagate into the + + align:start position:0% +wave has phases that propagate into the + + + align:start position:0% +wave has phases that propagate into the +conductor for \ No newline at end of file diff --git a/_CdoRiNSrqI.txt b/_CdoRiNSrqI.txt new file mode 100644 index 0000000000000000000000000000000000000000..67263acc897d50f6ea0d76f9bcf33f4a853a2155 --- /dev/null +++ b/_CdoRiNSrqI.txt @@ -0,0 +1,7563 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT open courseware continue + + align:start position:0% +will help MIT open courseware continue + + + align:start position:0% +will help MIT open courseware continue +to offer highquality educational + + align:start position:0% +to offer highquality educational + + + align:start position:0% +to offer highquality educational +resources for free to make a donation or + + align:start position:0% +resources for free to make a donation or + + + align:start position:0% +resources for free to make a donation or +to view additional materials from + + align:start position:0% +to view additional materials from + + + align:start position:0% +to view additional materials from +hundreds of MIT courses visit MIT open + + align:start position:0% +hundreds of MIT courses visit MIT open + + + align:start position:0% +hundreds of MIT courses visit MIT open +courseware at + + align:start position:0% + + + + align:start position:0% + +ocw.mit.edu today I'm going to tell you + + align:start position:0% +ocw.mit.edu today I'm going to tell you + + + align:start position:0% +ocw.mit.edu today I'm going to tell you +about + + align:start position:0% + + + + align:start position:0% + +flux of uh vector bu through a curve + + align:start position:0% +flux of uh vector bu through a curve + + + align:start position:0% +flux of uh vector bu through a curve +so you know in case you've seen flux in + + align:start position:0% +so you know in case you've seen flux in + + + align:start position:0% +so you know in case you've seen flux in +physics probably you've seen flux in + + align:start position:0% +physics probably you've seen flux in + + + align:start position:0% +physics probably you've seen flux in +space and we're going to come to that in + + align:start position:0% +space and we're going to come to that in + + + align:start position:0% +space and we're going to come to that in +a couple of weeks but for now we still + + align:start position:0% +a couple of weeks but for now we still + + + align:start position:0% +a couple of weeks but for now we still +doing everything in the plane so you + + align:start position:0% +doing everything in the plane so you + + + align:start position:0% +doing everything in the plane so you +know bear with me if you've seen a more + + align:start position:0% +know bear with me if you've seen a more + + + align:start position:0% +know bear with me if you've seen a more +complicated version of flux we're going + + align:start position:0% +complicated version of flux we're going + + + align:start position:0% +complicated version of flux we're going +to do the easy one + + align:start position:0% +to do the easy one + + + align:start position:0% +to do the easy one +first uh so what is flux well flux it's + + align:start position:0% +first uh so what is flux well flux it's + + + align:start position:0% +first uh so what is flux well flux it's +actually another kind of line ingal + + align:start position:0% + + + + align:start position:0% + +so let's say that I have a plain + + align:start position:0% + + + + align:start position:0% + +curve and a vector fied in the + + align:start position:0% + + + + align:start position:0% + +plane then the + + align:start position:0% +plane then the + + + align:start position:0% +plane then the +flux of + + align:start position:0% +flux of + + + align:start position:0% +flux of +f across a curve + + align:start position:0% +f across a curve + + + align:start position:0% +f across a curve +C is by definition it's a line integral + + align:start position:0% +C is by definition it's a line integral + + + align:start position:0% +C is by definition it's a line integral +but I will use I will use notation f. n + + align:start position:0% +but I will use I will use notation f. n + + + align:start position:0% +but I will use I will use notation f. n +DS so I have to explain to you what it + + align:start position:0% + + + + align:start position:0% + +means but let me first box that because + + align:start position:0% +means but let me first box that because + + + align:start position:0% +means but let me first box that because +that's the important formula to remember + + align:start position:0% +that's the important formula to remember + + + align:start position:0% +that's the important formula to remember +that's the + + align:start position:0% + + + + align:start position:0% + +definition so what does that + + align:start position:0% +definition so what does that + + + align:start position:0% +definition so what does that +mean so first I mean I have mostly I + + align:start position:0% +mean so first I mean I have mostly I + + + align:start position:0% +mean so first I mean I have mostly I +have to tell you what is this little n + + align:start position:0% +have to tell you what is this little n + + + align:start position:0% +have to tell you what is this little n +so n the notation suggests you know it's + + align:start position:0% +so n the notation suggests you know it's + + + align:start position:0% +so n the notation suggests you know it's +a normal Vector so what does what does + + align:start position:0% +a normal Vector so what does what does + + + align:start position:0% +a normal Vector so what does what does +that + + align:start position:0% + + + + align:start position:0% + +mean so I have a curve in the + + align:start position:0% +mean so I have a curve in the + + + align:start position:0% +mean so I have a curve in the +plane and I have a vector + + align:start position:0% + + + + align:start position:0% + +field let's see my Vector field will be + + align:start position:0% +field let's see my Vector field will be + + + align:start position:0% +field let's see my Vector field will be +yellow + + align:start position:0% + + + + align:start position:0% + +today and I will want to integrate along + + align:start position:0% +today and I will want to integrate along + + + align:start position:0% +today and I will want to integrate along +the Curve + + align:start position:0% +the Curve + + + align:start position:0% +the Curve +the dot product of f with the normal + + align:start position:0% +the dot product of f with the normal + + + align:start position:0% +the dot product of f with the normal +Vector to the curve the unit normal + + align:start position:0% +Vector to the curve the unit normal + + + align:start position:0% +Vector to the curve the unit normal +Vector to the curve so that means a + + align:start position:0% +Vector to the curve so that means a + + + align:start position:0% +Vector to the curve so that means a +vector that's at every point of the + + align:start position:0% +vector that's at every point of the + + + align:start position:0% +vector that's at every point of the +curve + + align:start position:0% +curve + + + align:start position:0% +curve +perpendicular to the curve and of length + + align:start position:0% +perpendicular to the curve and of length + + + align:start position:0% +perpendicular to the curve and of length +one + + align:start position:0% + + + + align:start position:0% + +so n + + align:start position:0% +so n + + + align:start position:0% +so n +everywhere will + + align:start position:0% + + + + align:start position:0% + +be the unit + + align:start position:0% +be the unit + + + align:start position:0% +be the unit +normal + + align:start position:0% + + + + align:start position:0% + +Vector to the curve + + align:start position:0% +Vector to the curve + + + align:start position:0% +Vector to the curve +C pointing 90° + + align:start position:0% +C pointing 90° + + + align:start position:0% +C pointing 90° +clockwise from + + align:start position:0% + + + + align:start position:0% + +T so what does that mean that means you + + align:start position:0% +T so what does that mean that means you + + + align:start position:0% +T so what does that mean that means you +know I have two normal vectors one + + align:start position:0% +know I have two normal vectors one + + + align:start position:0% +know I have two normal vectors one +that's pointing this way one that's + + align:start position:0% +that's pointing this way one that's + + + align:start position:0% +that's pointing this way one that's +pointing that way I have to choose a + + align:start position:0% +pointing that way I have to choose a + + + align:start position:0% +pointing that way I have to choose a +convention and the convention is that + + align:start position:0% +convention and the convention is that + + + align:start position:0% +convention and the convention is that +the normal Vector that I take goes to + + align:start position:0% +the normal Vector that I take goes to + + + align:start position:0% +the normal Vector that I take goes to +the right of the Curve as I'm traveling + + align:start position:0% +the right of the Curve as I'm traveling + + + align:start position:0% +the right of the Curve as I'm traveling +along the curve so see imagine that + + align:start position:0% +along the curve so see imagine that + + + align:start position:0% +along the curve so see imagine that +you're walking along this curve then you + + align:start position:0% +you're walking along this curve then you + + + align:start position:0% +you're walking along this curve then you +look to your right that's that + + align:start position:0% +look to your right that's that + + + align:start position:0% +look to your right that's that +direction + + align:start position:0% +direction + + + align:start position:0% +direction +okay so what we will do is we'll just at + + align:start position:0% +okay so what we will do is we'll just at + + + align:start position:0% +okay so what we will do is we'll just at +every point along the curve we'll do the + + align:start position:0% +every point along the curve we'll do the + + + align:start position:0% +every point along the curve we'll do the +dot product between the vector field and + + align:start position:0% +dot product between the vector field and + + + align:start position:0% +dot product between the vector field and +the normal vector and we sum that along + + align:start position:0% +the normal vector and we sum that along + + + align:start position:0% +the normal vector and we sum that along +the various pieces of the + + align:start position:0% +the various pieces of the + + + align:start position:0% +the various pieces of the +curve so what this notation + + align:start position:0% +curve so what this notation + + + align:start position:0% +curve so what this notation +means is that if we actually break C + + align:start position:0% +means is that if we actually break C + + + align:start position:0% +means is that if we actually break C +into small + + align:start position:0% + + + + align:start position:0% + +pieces of length Delta + + align:start position:0% +pieces of length Delta + + + align:start position:0% +pieces of length Delta +s then the + + align:start position:0% +s then the + + + align:start position:0% +s then the +flux will be the + + align:start position:0% +flux will be the + + + align:start position:0% +flux will be the +limit as the pieces become smaller and + + align:start position:0% +limit as the pieces become smaller and + + + align:start position:0% +limit as the pieces become smaller and +smaller of the sum of f.n Delta s where + + align:start position:0% +smaller of the sum of f.n Delta s where + + + align:start position:0% +smaller of the sum of f.n Delta s where +you know so I take each small piece of + + align:start position:0% +you know so I take each small piece of + + + align:start position:0% +you know so I take each small piece of +my curve I do the dot product between F + + align:start position:0% +my curve I do the dot product between F + + + align:start position:0% +my curve I do the dot product between F +and N and I multiply by the length of + + align:start position:0% +and N and I multiply by the length of + + + align:start position:0% +and N and I multiply by the length of +the piece and then I add these together + + align:start position:0% +the piece and then I add these together + + + align:start position:0% +the piece and then I add these together +that's what the line integral means of + + align:start position:0% +that's what the line integral means of + + + align:start position:0% +that's what the line integral means of +course that's again not how I will + + align:start position:0% +course that's again not how I will + + + align:start position:0% +course that's again not how I will +compute + + align:start position:0% + + + + align:start position:0% + +it so just to compare this with work see + + align:start position:0% +it so just to compare this with work see + + + align:start position:0% +it so just to compare this with work see +conceptually it's similar to the line + + align:start position:0% +conceptually it's similar to the line + + + align:start position:0% +conceptually it's similar to the line +integral we did for work + + align:start position:0% + + + + align:start position:0% + +except well the line integral for work + + align:start position:0% + + + + align:start position:0% + +so sorry + + align:start position:0% + + + + align:start position:0% + +work is the line inte of + + align:start position:0% +work is the line inte of + + + align:start position:0% +work is the line inte of +f.d which is also the line integral of f + + align:start position:0% +f.d which is also the line integral of f + + + align:start position:0% +f.d which is also the line integral of f +do TDS that's how we formulated it that + + align:start position:0% +do TDS that's how we formulated it that + + + align:start position:0% +do TDS that's how we formulated it that +means you know we take our curve and we + + align:start position:0% +means you know we take our curve and we + + + align:start position:0% +means you know we take our curve and we +figure out at each + + align:start position:0% + + + + align:start position:0% + +point how big the tangent + + align:start position:0% +point how big the tangent + + + align:start position:0% +point how big the tangent +component I guess I should probably take + + align:start position:0% +component I guess I should probably take + + + align:start position:0% +component I guess I should probably take +the same Vector field as before so let's + + align:start position:0% +the same Vector field as before so let's + + + align:start position:0% +the same Vector field as before so let's +see my field was pointing mik that + + align:start position:0% +see my field was pointing mik that + + + align:start position:0% +see my field was pointing mik that +way so what I do at any point is I + + align:start position:0% +way so what I do at any point is I + + + align:start position:0% +way so what I do at any point is I +project F to the tangent Direction and I + + align:start position:0% +project F to the tangent Direction and I + + + align:start position:0% +project F to the tangent Direction and I +figure out how much f is going along my + + align:start position:0% +figure out how much f is going along my + + + align:start position:0% +figure out how much f is going along my +curve and then I sum these things + + align:start position:0% +curve and then I sum these things + + + align:start position:0% +curve and then I sum these things +together + + align:start position:0% +together + + + align:start position:0% +together +so you know I'm actually + + align:start position:0% +so you know I'm actually + + + align:start position:0% +so you know I'm actually +summing oh + + align:start position:0% + + + + align:start position:0% + +the tangential + + align:start position:0% + + + + align:start position:0% + +component of my field + + align:start position:0% +component of my field + + + align:start position:0% +component of my field +F okay + + align:start position:0% +F okay + + + align:start position:0% +F okay +so roughly speaking the work measures + + align:start position:0% +so roughly speaking the work measures + + + align:start position:0% +so roughly speaking the work measures +you know when I move along my curve how + + align:start position:0% +you know when I move along my curve how + + + align:start position:0% +you know when I move along my curve how +much I'm going with or against + + align:start position:0% +much I'm going with or against + + + align:start position:0% +much I'm going with or against +F flux on the other hand measures when I + + align:start position:0% +F flux on the other hand measures when I + + + align:start position:0% +F flux on the other hand measures when I +go along the curve roughly how much the + + align:start position:0% +go along the curve roughly how much the + + + align:start position:0% +go along the curve roughly how much the +field is going across the curve counting + + align:start position:0% +field is going across the curve counting + + + align:start position:0% +field is going across the curve counting +positively what goes to the right + + align:start position:0% +positively what goes to the right + + + align:start position:0% +positively what goes to the right +negatively what goes to the left okay so + + align:start position:0% +negatively what goes to the left okay so + + + align:start position:0% +negatively what goes to the left okay so +flux is integral of f. n + + align:start position:0% +flux is integral of f. n + + + align:start position:0% +flux is integral of f. n +DS and that one corresponds + + align:start position:0% +DS and that one corresponds + + + align:start position:0% +DS and that one corresponds +to summing the + + align:start position:0% + + + + align:start position:0% + +normal component of a vector + + align:start position:0% + + + + align:start position:0% + +field okay but apart from that + + align:start position:0% +field okay but apart from that + + + align:start position:0% +field okay but apart from that +conceptually it's the same kind of thing + + align:start position:0% +conceptually it's the same kind of thing + + + align:start position:0% +conceptually it's the same kind of thing +just the physical interpretations will + + align:start position:0% +just the physical interpretations will + + + align:start position:0% +just the physical interpretations will +be very different but for a + + align:start position:0% +be very different but for a + + + align:start position:0% +be very different but for a +mathematician these are two line + + align:start position:0% +mathematician these are two line + + + align:start position:0% +mathematician these are two line +integrals that you set up compute pretty + + align:start position:0% +integrals that you set up compute pretty + + + align:start position:0% +integrals that you set up compute pretty +much in the same + + align:start position:0% + + + + align:start position:0% + +way + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so let's see I should probably tell you + + align:start position:0% +so let's see I should probably tell you + + + align:start position:0% +so let's see I should probably tell you +what it means you know why do we make + + align:start position:0% +what it means you know why do we make + + + align:start position:0% +what it means you know why do we make +this definition what does it correspond + + align:start position:0% +this definition what does it correspond + + + align:start position:0% +this definition what does it correspond +to so the interpretation for work made a + + align:start position:0% +to so the interpretation for work made a + + + align:start position:0% +to so the interpretation for work made a +lot of sense when f was representing a + + align:start position:0% +lot of sense when f was representing a + + + align:start position:0% +lot of sense when f was representing a +force then the L integral was actually + + align:start position:0% +force then the L integral was actually + + + align:start position:0% +force then the L integral was actually +the work done by the force the + + align:start position:0% +the work done by the force the + + + align:start position:0% +the work done by the force the +interpretation for flux makes more sense + + align:start position:0% +interpretation for flux makes more sense + + + align:start position:0% +interpretation for flux makes more sense +if you think of f as a velocity field + + align:start position:0% +if you think of f as a velocity field + + + align:start position:0% +if you think of f as a velocity field +okay so what's the + + align:start position:0% + + + + align:start position:0% + +interpretation let's say that + + align:start position:0% +interpretation let's say that + + + align:start position:0% +interpretation let's say that +f for f a velocity field so that means + + align:start position:0% +f for f a velocity field so that means + + + align:start position:0% +f for f a velocity field so that means +you know + + align:start position:0% +you know + + + align:start position:0% +you know +I'm thinking of some fluid that's moving + + align:start position:0% +I'm thinking of some fluid that's moving + + + align:start position:0% +I'm thinking of some fluid that's moving +maybe water or something and it's moving + + align:start position:0% +maybe water or something and it's moving + + + align:start position:0% +maybe water or something and it's moving +at a certain speed and my Vector field + + align:start position:0% +at a certain speed and my Vector field + + + align:start position:0% +at a certain speed and my Vector field +represents how things are moving at + + align:start position:0% +represents how things are moving at + + + align:start position:0% +represents how things are moving at +every point of the + + align:start position:0% +every point of the + + + align:start position:0% +every point of the +plane + + align:start position:0% +plane + + + align:start position:0% +plane +so I claim that flux + + align:start position:0% + + + + align:start position:0% + +measures how much fluid passes + + align:start position:0% + + + + align:start position:0% + +through through a curve C per unit + + align:start position:0% + + + + align:start position:0% + +time so if you imagine that you know + + align:start position:0% +time so if you imagine that you know + + + align:start position:0% +time so if you imagine that you know +maybe you have a river and you're + + align:start position:0% +maybe you have a river and you're + + + align:start position:0% +maybe you have a river and you're +somehow building a dam here but you know + + align:start position:0% +somehow building a dam here but you know + + + align:start position:0% +somehow building a dam here but you know +a dam with holes in it so that the water + + align:start position:0% +a dam with holes in it so that the water + + + align:start position:0% +a dam with holes in it so that the water +still passes through then this measures + + align:start position:0% +still passes through then this measures + + + align:start position:0% +still passes through then this measures +how much water passes through your + + align:start position:0% +how much water passes through your + + + align:start position:0% +how much water passes through your +membrane per unit + + align:start position:0% +membrane per unit + + + align:start position:0% +membrane per unit +time okay let's try to figure out why + + align:start position:0% +time okay let's try to figure out why + + + align:start position:0% +time okay let's try to figure out why +this is true you know why does this make + + align:start position:0% +this is true you know why does this make + + + align:start position:0% +this is true you know why does this make +sense + + align:start position:0% +sense + + + align:start position:0% +sense +so let's look at what happens on a small + + align:start position:0% +so let's look at what happens on a small + + + align:start position:0% +so let's look at what happens on a small +portion of our curve + + align:start position:0% +portion of our curve + + + align:start position:0% +portion of our curve +C so I'm zooming in on make of C sorry + + align:start position:0% + + + + align:start position:0% + +to guess I need to zoom further + + align:start position:0% +to guess I need to zoom further + + + align:start position:0% +to guess I need to zoom further +okay so you know that's a little piece + + align:start position:0% +okay so you know that's a little piece + + + align:start position:0% +okay so you know that's a little piece +of my curve of length Delta s and + + align:start position:0% +of my curve of length Delta s and + + + align:start position:0% +of my curve of length Delta s and +there's a fluid flow so on my picture + + align:start position:0% +there's a fluid flow so on my picture + + + align:start position:0% +there's a fluid flow so on my picture +things are flowing to the + + align:start position:0% +things are flowing to the + + + align:start position:0% +things are flowing to the +right so here I'm drawing a constant + + align:start position:0% +right so here I'm drawing a constant + + + align:start position:0% +right so here I'm drawing a constant +Vector field because you know if you + + align:start position:0% +Vector field because you know if you + + + align:start position:0% +Vector field because you know if you +zoom in enough then your vectors will + + align:start position:0% +zoom in enough then your vectors will + + + align:start position:0% +zoom in enough then your vectors will +pretty much be the same + + align:start position:0% +pretty much be the same + + + align:start position:0% +pretty much be the same +everywhere right if you you know enlarge + + align:start position:0% +everywhere right if you you know enlarge + + + align:start position:0% +everywhere right if you you know enlarge +the picture enough then things will be + + align:start position:0% +the picture enough then things will be + + + align:start position:0% +the picture enough then things will be +pretty much a uniform flow so now how + + align:start position:0% +pretty much a uniform flow so now how + + + align:start position:0% +pretty much a uniform flow so now how +much stuff goes through this little + + align:start position:0% +much stuff goes through this little + + + align:start position:0% +much stuff goes through this little +piece of curve per unit time well what + + align:start position:0% +piece of curve per unit time well what + + + align:start position:0% +piece of curve per unit time well what +happens over time the fluid is moving + + align:start position:0% +happens over time the fluid is moving + + + align:start position:0% +happens over time the fluid is moving +while my curve is staying in the same + + align:start position:0% +while my curve is staying in the same + + + align:start position:0% +while my curve is staying in the same +place so corresponds to something like + + align:start position:0% +place so corresponds to something like + + + align:start position:0% +place so corresponds to something like +this + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so I claim that what goes through C in + + align:start position:0% +so I claim that what goes through C in + + + align:start position:0% +so I claim that what goes through C in +unit time is actually going to + + align:start position:0% + + + + align:start position:0% + +be is actually going to be a + + align:start position:0% +be is actually going to be a + + + align:start position:0% +be is actually going to be a +parallelogram okay so here's a better + + align:start position:0% +parallelogram okay so here's a better + + + align:start position:0% +parallelogram okay so here's a better +picture I claim that what we'll be going + + align:start position:0% +picture I claim that what we'll be going + + + align:start position:0% +picture I claim that what we'll be going +through C is this shaded parallelogram + + align:start position:0% +through C is this shaded parallelogram + + + align:start position:0% +through C is this shaded parallelogram +to the left of C well let's see if I + + align:start position:0% +to the left of C well let's see if I + + + align:start position:0% +to the left of C well let's see if I +move for unit time + + align:start position:0% + + + + align:start position:0% + +okay it + + align:start position:0% +okay it + + + align:start position:0% +okay it +works okay so that's the stuff that goes + + align:start position:0% +works okay so that's the stuff that goes + + + align:start position:0% +works okay so that's the stuff that goes +through my curve in a unit time for a + + align:start position:0% +through my curve in a unit time for a + + + align:start position:0% +through my curve in a unit time for a +small portion of curve and of course I + + align:start position:0% +small portion of curve and of course I + + + align:start position:0% +small portion of curve and of course I +would need to add all of these together + + align:start position:0% +would need to add all of these together + + + align:start position:0% +would need to add all of these together +to get the entire curve so let's try to + + align:start position:0% +to get the entire curve so let's try to + + + align:start position:0% +to get the entire curve so let's try to +understand how big is this + + align:start position:0% +understand how big is this + + + align:start position:0% +understand how big is this +parallelogram so you know to know how + + align:start position:0% +parallelogram so you know to know how + + + align:start position:0% +parallelogram so you know to know how +big this parogram is I would like to use + + align:start position:0% +big this parogram is I would like to use + + + align:start position:0% +big this parogram is I would like to use +base time height or something like that + + align:start position:0% +base time height or something like that + + + align:start position:0% +base time height or something like that +and maybe I want to actually flip my + + align:start position:0% +and maybe I want to actually flip my + + + align:start position:0% +and maybe I want to actually flip my +picture so that the base and the height + + align:start position:0% +picture so that the base and the height + + + align:start position:0% +picture so that the base and the height +make more sense to me so let me actually + + align:start position:0% +make more sense to me so let me actually + + + align:start position:0% +make more sense to me so let me actually +turn it to + + align:start position:0% + + + + align:start position:0% + +this okay and in case you have trouble + + align:start position:0% +this okay and in case you have trouble + + + align:start position:0% +this okay and in case you have trouble +reading the rotated picture let me redo + + align:start position:0% +reading the rotated picture let me redo + + + align:start position:0% +reading the rotated picture let me redo +it on the + + align:start position:0% + + + + align:start position:0% + +board + + align:start position:0% + + + + align:start position:0% + +so what passes + + align:start position:0% +so what passes + + + align:start position:0% +so what passes +through a + + align:start position:0% +through a + + + align:start position:0% +through a +portion of C in unit time + + align:start position:0% + + + + align:start position:0% + +time is the contents of a parallelogram + + align:start position:0% +time is the contents of a parallelogram + + + align:start position:0% +time is the contents of a parallelogram +whose base is on C so it has length + + align:start position:0% +whose base is on C so it has length + + + align:start position:0% +whose base is on C so it has length +Delta s okay that's that's a piece + + align:start position:0% +Delta s okay that's that's a piece + + + align:start position:0% +Delta s okay that's that's a piece +of + + align:start position:0% + + + + align:start position:0% + +c + + align:start position:0% +c + + + align:start position:0% +c +and the other + + align:start position:0% +and the other + + + align:start position:0% +and the other +side is going to + + align:start position:0% +side is going to + + + align:start position:0% +side is going to +be given by my velocity Vector f + + align:start position:0% + + + + align:start position:0% + +and to find the height of this thing I + + align:start position:0% +and to find the height of this thing I + + + align:start position:0% +and to find the height of this thing I +need to know well what is actually the + + align:start position:0% +need to know well what is actually the + + + align:start position:0% +need to know well what is actually the +normal component of this + + align:start position:0% +normal component of this + + + align:start position:0% +normal component of this +Vector right so if I call n the the unit + + align:start position:0% +Vector right so if I call n the the unit + + + align:start position:0% +Vector right so if I call n the the unit +normal + + align:start position:0% +normal + + + align:start position:0% +normal +Vector to the curve then the area + + align:start position:0% +Vector to the curve then the area + + + align:start position:0% +Vector to the curve then the area +is base time + + align:start position:0% +is base time + + + align:start position:0% +is base time +height is just so the base is Delta s + + align:start position:0% +height is just so the base is Delta s + + + align:start position:0% +height is just so the base is Delta s +and the height is the normal component + + align:start position:0% +and the height is the normal component + + + align:start position:0% +and the height is the normal component +of f so it's + + align:start position:0% + + + + align:start position:0% + +f.n and so you see that when you sum + + align:start position:0% +f.n and so you see that when you sum + + + align:start position:0% +f.n and so you see that when you sum +these things together you get what I + + align:start position:0% +these things together you get what I + + + align:start position:0% +these things together you get what I +said you get + + align:start position:0% + + + + align:start position:0% + +flux now if you're worried about the + + align:start position:0% +flux now if you're worried about the + + + align:start position:0% +flux now if you're worried about the +fact that actually you know if your unit + + align:start position:0% +fact that actually you know if your unit + + + align:start position:0% +fact that actually you know if your unit +time is too long then of course things + + align:start position:0% +time is too long then of course things + + + align:start position:0% +time is too long then of course things +might start changing you know as the + + align:start position:0% +might start changing you know as the + + + align:start position:0% +might start changing you know as the +fluid flows I mean it might so you have + + align:start position:0% +fluid flows I mean it might so you have + + + align:start position:0% +fluid flows I mean it might so you have +to take a Time unit and a length unit + + align:start position:0% +to take a Time unit and a length unit + + + align:start position:0% +to take a Time unit and a length unit +that are sufficiently small so that + + align:start position:0% +that are sufficiently small so that + + + align:start position:0% +that are sufficiently small so that +really this approximation where C is a + + align:start position:0% +really this approximation where C is a + + + align:start position:0% +really this approximation where C is a +straight line and the flow is at + + align:start position:0% +straight line and the flow is at + + + align:start position:0% +straight line and the flow is at +constant speed are valid so you know you + + align:start position:0% +constant speed are valid so you know you + + + align:start position:0% +constant speed are valid so you know you +want to take maybe a segment here that's + + align:start position:0% +want to take maybe a segment here that's + + + align:start position:0% +want to take maybe a segment here that's +like a few micrometers and you know the + + align:start position:0% +like a few micrometers and you know the + + + align:start position:0% +like a few micrometers and you know the +time unit might be a few NS or whatever + + align:start position:0% +time unit might be a few NS or whatever + + + align:start position:0% +time unit might be a few NS or whatever +and then it's a good + + align:start position:0% +and then it's a good + + + align:start position:0% +and then it's a good +approximation um so what I mean by per + + align:start position:0% +approximation um so what I mean by per + + + align:start position:0% +approximation um so what I mean by per +unit time actually it's V you + + align:start position:0% +unit time actually it's V you + + + align:start position:0% +unit time actually it's V you +know well yeah actually that works but + + align:start position:0% +know well yeah actually that works but + + + align:start position:0% +know well yeah actually that works but +you know you want to think of a really + + align:start position:0% +you know you want to think of a really + + + align:start position:0% +you know you want to think of a really +really small time and then the amount of + + align:start position:0% +really small time and then the amount of + + + align:start position:0% +really small time and then the amount of +matter that passes in that really really + + align:start position:0% +matter that passes in that really really + + + align:start position:0% +matter that passes in that really really +small time + + align:start position:0% +small time + + + align:start position:0% +small time +is the flux times the amount of + + align:start position:0% +is the flux times the amount of + + + align:start position:0% +is the flux times the amount of +time okay um let's be a tiny bit more + + align:start position:0% +time okay um let's be a tiny bit more + + + align:start position:0% +time okay um let's be a tiny bit more +careful when I'm saying it's the amount + + align:start position:0% +careful when I'm saying it's the amount + + + align:start position:0% +careful when I'm saying it's the amount +of stuff that passes through C well it + + align:start position:0% +of stuff that passes through C well it + + + align:start position:0% +of stuff that passes through C well it +depends actually on whether n is going + + align:start position:0% +depends actually on whether n is going + + + align:start position:0% +depends actually on whether n is going +this way or the or the opposite way so + + align:start position:0% +this way or the or the opposite way so + + + align:start position:0% +this way or the or the opposite way so +actually you know what's implicit in + + align:start position:0% +actually you know what's implicit in + + + align:start position:0% +actually you know what's implicit in +this + + align:start position:0% +this + + + align:start position:0% +this +explanation is that I'm counting + + align:start position:0% +explanation is that I'm counting + + + align:start position:0% +explanation is that I'm counting +positively all the stuff that flows + + align:start position:0% +positively all the stuff that flows + + + align:start position:0% +positively all the stuff that flows +across C in the direction of N and + + align:start position:0% +across C in the direction of N and + + + align:start position:0% +across C in the direction of N and +negatively What flows in the opposite + + align:start position:0% + + + + align:start position:0% + +direction okay so what + + align:start position:0% + + + + align:start position:0% + +flows to the right of C + + align:start position:0% +flows to the right of C + + + align:start position:0% +flows to the right of C +towards well across + + align:start position:0% + + + + align:start position:0% + +C from left to right + + align:start position:0% + + + + align:start position:0% + +is counted + + align:start position:0% + + + + align:start position:0% + +positively while What flows right to + + align:start position:0% + + + + align:start position:0% + +left is counted + + align:start position:0% + + + + align:start position:0% + +negatively okay so in fact it's the net + + align:start position:0% +negatively okay so in fact it's the net + + + align:start position:0% +negatively okay so in fact it's the net +flow through C per unit time + + align:start position:0% + + + + align:start position:0% + +okay any questions about the definition + + align:start position:0% +okay any questions about the definition + + + align:start position:0% +okay any questions about the definition +or the + + align:start position:0% +or the + + + align:start position:0% +or the +interpretation or things like + + align:start position:0% + + + + align:start position:0% + +that + + align:start position:0% + + + + align:start position:0% + +yes how do you + + align:start position:0% + + + + align:start position:0% + +sorry ah well you can have both not in + + align:start position:0% +sorry ah well you can have both not in + + + align:start position:0% +sorry ah well you can have both not in +the same small segment but you know it + + align:start position:0% +the same small segment but you know it + + + align:start position:0% +the same small segment but you know it +could be that well imagine that you know + + align:start position:0% +could be that well imagine that you know + + + align:start position:0% +could be that well imagine that you know +my Vector field you know here suddenly + + align:start position:0% +my Vector field you know here suddenly + + + align:start position:0% +my Vector field you know here suddenly +you know goes in the opposite direction + + align:start position:0% +you know goes in the opposite direction + + + align:start position:0% +you know goes in the opposite direction +then this part of the curve while things + + align:start position:0% +then this part of the curve while things + + + align:start position:0% +then this part of the curve while things +are flowing to the left so this part of + + align:start position:0% +are flowing to the left so this part of + + + align:start position:0% +are flowing to the left so this part of +the curve contributes negatively to flux + + align:start position:0% +the curve contributes negatively to flux + + + align:start position:0% +the curve contributes negatively to flux +and here you know maybe a field is + + align:start position:0% +and here you know maybe a field is + + + align:start position:0% +and here you know maybe a field is +tangent so the normal component becomes + + align:start position:0% +tangent so the normal component becomes + + + align:start position:0% +tangent so the normal component becomes +zero and then it becomes positive and + + align:start position:0% +zero and then it becomes positive and + + + align:start position:0% +zero and then it becomes positive and +this part of the curve contributes + + align:start position:0% + + + + align:start position:0% + +positively you know for example you know + + align:start position:0% +positively you know for example you know + + + align:start position:0% +positively you know for example you know +if you imagine that you have a round + + align:start position:0% +if you imagine that you have a round + + + align:start position:0% +if you imagine that you have a round +tank in which the fluid is rotating and + + align:start position:0% +tank in which the fluid is rotating and + + + align:start position:0% +tank in which the fluid is rotating and +you put your Dam you know just on a + + align:start position:0% +you put your Dam you know just on a + + + align:start position:0% +you put your Dam you know just on a +diameter across then things are going + + align:start position:0% +diameter across then things are going + + + align:start position:0% +diameter across then things are going +one way on one side the have way on the + + align:start position:0% +one way on one side the have way on the + + + align:start position:0% +one way on one side the have way on the +other side and actually it just evens + + align:start position:0% +other side and actually it just evens + + + align:start position:0% +other side and actually it just evens +out + + align:start position:0% +out + + + align:start position:0% +out +um yeah so we don't have complete + + align:start position:0% +um yeah so we don't have complete + + + align:start position:0% +um yeah so we don't have complete +information it's just the total net + + align:start position:0% + + + + align:start position:0% + +flux okay so if there's no other + + align:start position:0% +flux okay so if there's no other + + + align:start position:0% +flux okay so if there's no other +questions then I guess we'll need to + + align:start position:0% +questions then I guess we'll need to + + + align:start position:0% +questions then I guess we'll need to +figure out how to compute this guy and + + align:start position:0% +figure out how to compute this guy and + + + align:start position:0% +figure out how to compute this guy and +you know how to actually do this line + + align:start position:0% +you know how to actually do this line + + + align:start position:0% +you know how to actually do this line +integral + + align:start position:0% + + + + align:start position:0% + +so well let's start with a couple of + + align:start position:0% +so well let's start with a couple of + + + align:start position:0% +so well let's start with a couple of +easy examples + + align:start position:0% + + + + align:start position:0% + +okay so let's say that + + align:start position:0% +okay so let's say that + + + align:start position:0% +okay so let's say that +c is a + + align:start position:0% +c is a + + + align:start position:0% +c is a +circle of radius + + align:start position:0% +circle of radius + + + align:start position:0% +circle of radius +a centered at the + + align:start position:0% + + + + align:start position:0% + +origin going + + align:start position:0% + + + + align:start position:0% + +counterclockwise and let's say that our + + align:start position:0% +counterclockwise and let's say that our + + + align:start position:0% +counterclockwise and let's say that our +Vector field + + align:start position:0% +Vector field + + + align:start position:0% +Vector field +is x i + y + + align:start position:0% +is x i + y + + + align:start position:0% +is x i + y +j so what does that look + + align:start position:0% + + + + align:start position:0% + +like so remember x i + y j is a vector + + align:start position:0% +like so remember x i + y j is a vector + + + align:start position:0% +like so remember x i + y j is a vector +field that's pointing radially away from + + align:start position:0% +field that's pointing radially away from + + + align:start position:0% +field that's pointing radially away from +the + + align:start position:0% +the + + + align:start position:0% +the +origin right because at every point it's + + align:start position:0% +origin right because at every point it's + + + align:start position:0% +origin right because at every point it's +equal to the vector from the origin to + + align:start position:0% +equal to the vector from the origin to + + + align:start position:0% +equal to the vector from the origin to +that + + align:start position:0% +that + + + align:start position:0% +that +point so now if we + + align:start position:0% +point so now if we + + + align:start position:0% +point so now if we +have a + + align:start position:0% + + + + align:start position:0% + +circle and let's say we're going + + align:start position:0% +circle and let's say we're going + + + align:start position:0% +circle and let's say we're going +counterclock + + align:start position:0% +counterclock + + + align:start position:0% +counterclock +so I have a nicer picture so let me do + + align:start position:0% +so I have a nicer picture so let me do + + + align:start position:0% +so I have a nicer picture so let me do +it + + align:start position:0% + + + + align:start position:0% + +here okay so + + align:start position:0% +here okay so + + + align:start position:0% +here okay so +that's my curve and my Vector + + align:start position:0% + + + + align:start position:0% + +field + + align:start position:0% +field + + + align:start position:0% +field +and well so the normal Vector C when you + + align:start position:0% +and well so the normal Vector C when you + + + align:start position:0% +and well so the normal Vector C when you +go counterclockwise on a closed curve + + align:start position:0% +go counterclockwise on a closed curve + + + align:start position:0% +go counterclockwise on a closed curve +this convention that the normal vector + + align:start position:0% +this convention that the normal vector + + + align:start position:0% +this convention that the normal vector +points to the right of a curve makes it + + align:start position:0% +points to the right of a curve makes it + + + align:start position:0% +points to the right of a curve makes it +point out so the usual convention when + + align:start position:0% +point out so the usual convention when + + + align:start position:0% +point out so the usual convention when +you take flux through a closed curve is + + align:start position:0% +you take flux through a closed curve is + + + align:start position:0% +you take flux through a closed curve is +that you're counting the flux going out + + align:start position:0% +that you're counting the flux going out + + + align:start position:0% +that you're counting the flux going out +of the region enclosed by the + + align:start position:0% +of the region enclosed by the + + + align:start position:0% +of the region enclosed by the +curve and of course if you went + + align:start position:0% +curve and of course if you went + + + align:start position:0% +curve and of course if you went +clockwise it would be the other way + + align:start position:0% +clockwise it would be the other way + + + align:start position:0% +clockwise it would be the other way +around you choose to do it the way you + + align:start position:0% +around you choose to do it the way you + + + align:start position:0% +around you choose to do it the way you +want but the usual the most common one + + align:start position:0% +want but the usual the most common one + + + align:start position:0% +want but the usual the most common one +is to count flux going out of a + + align:start position:0% + + + + align:start position:0% + +region so + + align:start position:0% +region so + + + align:start position:0% +region so +let's see what happens well if I'm + + align:start position:0% +let's see what happens well if I'm + + + align:start position:0% +let's see what happens well if I'm +anywhere on my + + align:start position:0% +anywhere on my + + + align:start position:0% +anywhere on my +circle see the normal Vector is sticking + + align:start position:0% +circle see the normal Vector is sticking + + + align:start position:0% +circle see the normal Vector is sticking +straight out of a circle right that's a + + align:start position:0% +straight out of a circle right that's a + + + align:start position:0% +straight out of a circle right that's a +property of a circle that the radial + + align:start position:0% +property of a circle that the radial + + + align:start position:0% +property of a circle that the radial +direction is perpendicular to the circle + + align:start position:0% +direction is perpendicular to the circle + + + align:start position:0% +direction is perpendicular to the circle +so actually let me complete a withit + + align:start position:0% +so actually let me complete a withit + + + align:start position:0% +so actually let me complete a withit +this picture if I take a point on the + + align:start position:0% +this picture if I take a point on the + + + align:start position:0% +this picture if I take a point on the +circle I have my normal + + align:start position:0% +circle I have my normal + + + align:start position:0% +circle I have my normal +Vector that's pointing straight out so + + align:start position:0% +Vector that's pointing straight out so + + + align:start position:0% +Vector that's pointing straight out so +it's parallel to f + + align:start position:0% +it's parallel to f + + + align:start position:0% +it's parallel to f +okay so along + + align:start position:0% +okay so along + + + align:start position:0% +okay so along +c we know that f is parallel to n so + + align:start position:0% +c we know that f is parallel to n so + + + align:start position:0% +c we know that f is parallel to n so +f.n will be equal to the length the + + align:start position:0% +f.n will be equal to the length the + + + align:start position:0% +f.n will be equal to the length the +magnitude of f times well the magnitude + + align:start position:0% +magnitude of f times well the magnitude + + + align:start position:0% +magnitude of f times well the magnitude +of n but that's one let me put it anyway + + align:start position:0% +of n but that's one let me put it anyway + + + align:start position:0% +of n but that's one let me put it anyway +but that's a unit normal + + align:start position:0% +but that's a unit normal + + + align:start position:0% +but that's a unit normal +Vector now What's the magnitude of this + + align:start position:0% +Vector now What's the magnitude of this + + + align:start position:0% +Vector now What's the magnitude of this +Vector field if I'm at a point x y well + + align:start position:0% +Vector field if I'm at a point x y well + + + align:start position:0% +Vector field if I'm at a point x y well +it's Square OT of x + y^2 that's the + + align:start position:0% +it's Square OT of x + y^2 that's the + + + align:start position:0% +it's Square OT of x + y^2 that's the +same as the distance from the origin + + align:start position:0% +same as the distance from the origin + + + align:start position:0% +same as the distance from the origin +okay so if this + + align:start position:0% + + + + align:start position:0% + +distance if this radius is a then the + + align:start position:0% +distance if this radius is a then the + + + align:start position:0% +distance if this radius is a then the +magnitude of f will just be + + align:start position:0% +magnitude of f will just be + + + align:start position:0% +magnitude of f will just be +a + + align:start position:0% +a + + + align:start position:0% +a +right so in + + align:start position:0% +right so in + + + align:start position:0% +right so in +fact f.n is constant always equal to a + + align:start position:0% +fact f.n is constant always equal to a + + + align:start position:0% +fact f.n is constant always equal to a +so the line integral will be pretty easy + + align:start position:0% +so the line integral will be pretty easy + + + align:start position:0% +so the line integral will be pretty easy +because all I have to + + align:start position:0% +because all I have to + + + align:start position:0% +because all I have to +do is the integral + + align:start position:0% +do is the integral + + + align:start position:0% +do is the integral +of f. n DS becomes the integral of a DS + + align:start position:0% +of f. n DS becomes the integral of a DS + + + align:start position:0% +of f. n DS becomes the integral of a DS +a is a constant so I can take it out and + + align:start position:0% +a is a constant so I can take it out and + + + align:start position:0% +a is a constant so I can take it out and +integral DS is just the length of + + align:start position:0% +integral DS is just the length of + + + align:start position:0% +integral DS is just the length of +C which is 2 pi a so I will get 2 pi a + + align:start position:0% + + + + align:start position:0% + +2 okay and that is positive as we + + align:start position:0% +2 okay and that is positive as we + + + align:start position:0% +2 okay and that is positive as we +expected because stuff is Flowing out of + + align:start position:0% +expected because stuff is Flowing out of + + + align:start position:0% +expected because stuff is Flowing out of +a circle + + align:start position:0% + + + + align:start position:0% + +okay any questions about + + align:start position:0% + + + + align:start position:0% + +that + + align:start position:0% + + + + align:start position:0% + +no okay just out of curiosity let's say + + align:start position:0% +no okay just out of curiosity let's say + + + align:start position:0% +no okay just out of curiosity let's say +that we had taken our other favorite + + align:start position:0% +that we had taken our other favorite + + + align:start position:0% +that we had taken our other favorite +Vector + + align:start position:0% +Vector + + + align:start position:0% +Vector +field so let's say that we had the same + + align:start position:0% +field so let's say that we had the same + + + align:start position:0% +field so let's say that we had the same +C but + + align:start position:0% +C but + + + align:start position:0% +C but +now the vector field negative y comma X + + align:start position:0% +now the vector field negative y comma X + + + align:start position:0% +now the vector field negative y comma X +so remember that one + + align:start position:0% +so remember that one + + + align:start position:0% +so remember that one +goes + + align:start position:0% +goes + + + align:start position:0% +goes +counterclockwise around the + + align:start position:0% +counterclockwise around the + + + align:start position:0% +counterclockwise around the +origin + + align:start position:0% +origin + + + align:start position:0% +origin +okay so if you remember what we did + + align:start position:0% +okay so if you remember what we did + + + align:start position:0% +okay so if you remember what we did +several times Well along the circle that + + align:start position:0% +several times Well along the circle that + + + align:start position:0% +several times Well along the circle that +Vector field now is tangent to the + + align:start position:0% + + + + align:start position:0% + +circle so if it's tangent to the circle + + align:start position:0% +circle so if it's tangent to the circle + + + align:start position:0% +circle so if it's tangent to the circle +it doesn't have any normal component the + + align:start position:0% +it doesn't have any normal component the + + + align:start position:0% +it doesn't have any normal component the +normal component is + + align:start position:0% +normal component is + + + align:start position:0% +normal component is +zero right things are not flowing into + + align:start position:0% +zero right things are not flowing into + + + align:start position:0% +zero right things are not flowing into +the circle or out of it they're just + + align:start position:0% +the circle or out of it they're just + + + align:start position:0% +the circle or out of it they're just +flowing along the circle around and + + align:start position:0% +flowing along the circle around and + + + align:start position:0% +flowing along the circle around and +around so the flux will be + + align:start position:0% +around so the flux will be + + + align:start position:0% +around so the flux will be +zero okay F now is tangent to + + align:start position:0% + + + + align:start position:0% + +C so + + align:start position:0% +C so + + + align:start position:0% +C so +f.n is zero and therefore the flux will + + align:start position:0% +f.n is zero and therefore the flux will + + + align:start position:0% +f.n is zero and therefore the flux will +be + + align:start position:0% + + + + align:start position:0% + +zero okay so these are examples where + + align:start position:0% +zero okay so these are examples where + + + align:start position:0% +zero okay so these are examples where +you can compute things + + align:start position:0% +you can compute things + + + align:start position:0% +you can compute things +geometrically and I would say generally + + align:start position:0% +geometrically and I would say generally + + + align:start position:0% +geometrically and I would say generally +speaking + + align:start position:0% +speaking + + + align:start position:0% +speaking +with + + align:start position:0% +with + + + align:start position:0% +with +flux you you know well if it's a very + + align:start position:0% +flux you you know well if it's a very + + + align:start position:0% +flux you you know well if it's a very +complicated field then you can't but if + + align:start position:0% +complicated field then you can't but if + + + align:start position:0% +complicated field then you can't but if +a field is fairly simple you should be + + align:start position:0% +a field is fairly simple you should be + + + align:start position:0% +a field is fairly simple you should be +able to get some general feeling for + + align:start position:0% +able to get some general feeling for + + + align:start position:0% +able to get some general feeling for +whether your answer at least should be + + align:start position:0% +whether your answer at least should be + + + align:start position:0% +whether your answer at least should be +positive negative or zero just by + + align:start position:0% +positive negative or zero just by + + + align:start position:0% +positive negative or zero just by +thinking about which way is my flow + + align:start position:0% +thinking about which way is my flow + + + align:start position:0% +thinking about which way is my flow +going is it going across the curve one + + align:start position:0% +going is it going across the curve one + + + align:start position:0% +going is it going across the curve one +way or the other + + align:start position:0% + + + + align:start position:0% + +way okay still no questions about these + + align:start position:0% +way okay still no questions about these + + + align:start position:0% +way okay still no questions about these +examples + + align:start position:0% + + + + align:start position:0% + +no okay so next thing we need to know is + + align:start position:0% +no okay so next thing we need to know is + + + align:start position:0% +no okay so next thing we need to know is +how we actually compute these things you + + align:start position:0% +how we actually compute these things you + + + align:start position:0% +how we actually compute these things you +know because yeah here it works pretty + + align:start position:0% +know because yeah here it works pretty + + + align:start position:0% +know because yeah here it works pretty +well but what if you don't have a simple + + align:start position:0% +well but what if you don't have a simple + + + align:start position:0% +well but what if you don't have a simple +geometric interpretation what if I give + + align:start position:0% +geometric interpretation what if I give + + + align:start position:0% +geometric interpretation what if I give +you a really complicated + + align:start position:0% +you a really complicated + + + align:start position:0% +you a really complicated +curve and you know then you have trouble + + align:start position:0% +curve and you know then you have trouble + + + align:start position:0% +curve and you know then you have trouble +finding the normal Vector it's going to + + align:start position:0% +finding the normal Vector it's going to + + + align:start position:0% +finding the normal Vector it's going to +be annoying to set up things this way so + + align:start position:0% +be annoying to set up things this way so + + + align:start position:0% +be annoying to set up things this way so +actually there's a better way to do it + + align:start position:0% +actually there's a better way to do it + + + align:start position:0% +actually there's a better way to do it +in + + align:start position:0% +in + + + align:start position:0% +in +coordinates just as you know when we do + + align:start position:0% +coordinates just as you know when we do + + + align:start position:0% +coordinates just as you know when we do +work when we compute this line integral + + align:start position:0% +work when we compute this line integral + + + align:start position:0% +work when we compute this line integral +usually we don't do it geometrically + + align:start position:0% +usually we don't do it geometrically + + + align:start position:0% +usually we don't do it geometrically +like this most of the time we just + + align:start position:0% +like this most of the time we just + + + align:start position:0% +like this most of the time we just +integrate MDX plus n Dy in + + align:start position:0% +integrate MDX plus n Dy in + + + align:start position:0% +integrate MDX plus n Dy in +coordinates so there's a similar way to + + align:start position:0% +coordinates so there's a similar way to + + + align:start position:0% +coordinates so there's a similar way to +do it because it's again a line integral + + align:start position:0% +do it because it's again a line integral + + + align:start position:0% +do it because it's again a line integral +so it should work the same + + align:start position:0% + + + + align:start position:0% + +way so let's try to figure that + + align:start position:0% + + + + align:start position:0% + +out for + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so how do we do the + + align:start position:0% + + + + align:start position:0% + +calculation in + + align:start position:0% +calculation in + + + align:start position:0% +calculation in +coordinates or I should say maybe using + + align:start position:0% + + + + align:start position:0% + +components so you know that's General + + align:start position:0% +components so you know that's General + + + align:start position:0% +components so you know that's General +method of calculation when we don't have + + align:start position:0% +method of calculation when we don't have + + + align:start position:0% +method of calculation when we don't have +something geometric to do so + + align:start position:0% + + + + align:start position:0% + +remember when we were doing things for + + align:start position:0% +remember when we were doing things for + + + align:start position:0% +remember when we were doing things for +work we said this Vector Dr or if you + + align:start position:0% +work we said this Vector Dr or if you + + + align:start position:0% +work we said this Vector Dr or if you +prefer + + align:start position:0% +prefer + + + align:start position:0% +prefer +TDS we said just becomes symbolically DX + + align:start position:0% +TDS we said just becomes symbolically DX + + + align:start position:0% +TDS we said just becomes symbolically DX +and + + align:start position:0% +and + + + align:start position:0% +and +Dy so that you know when you do the line + + align:start position:0% +Dy so that you know when you do the line + + + align:start position:0% +Dy so that you know when you do the line +integral of f. Dr you get line integral + + align:start position:0% +integral of f. Dr you get line integral + + + align:start position:0% +integral of f. Dr you get line integral +of MD X Plus n + + align:start position:0% +of MD X Plus n + + + align:start position:0% +of MD X Plus n +Dy so now let's think for a second about + + align:start position:0% +Dy so now let's think for a second about + + + align:start position:0% +Dy so now let's think for a second about +how we would Express n + + align:start position:0% +how we would Express n + + + align:start position:0% +how we would Express n +DS well what is NDS compared to + + align:start position:0% +DS well what is NDS compared to + + + align:start position:0% +DS well what is NDS compared to +TDs well n is just T rotated by 90 Dees + + align:start position:0% +TDs well n is just T rotated by 90 Dees + + + align:start position:0% +TDs well n is just T rotated by 90 Dees +so NDS is TDS rotated by 90° you know + + align:start position:0% +so NDS is TDS rotated by 90° you know + + + align:start position:0% +so NDS is TDS rotated by 90° you know +that might sound a little bit outrageous + + align:start position:0% +that might sound a little bit outrageous + + + align:start position:0% +that might sound a little bit outrageous +because you know these are really + + align:start position:0% +because you know these are really + + + align:start position:0% +because you know these are really +symbolic notations but it + + align:start position:0% +symbolic notations but it + + + align:start position:0% +symbolic notations but it +works so probably I'm not going to spend + + align:start position:0% +works so probably I'm not going to spend + + + align:start position:0% +works so probably I'm not going to spend +too much time trying to convince you + + align:start position:0% +too much time trying to convince you + + + align:start position:0% +too much time trying to convince you +carefully but + + align:start position:0% +carefully but + + + align:start position:0% +carefully but +really if you go back to you know where + + align:start position:0% +really if you go back to you know where + + + align:start position:0% +really if you go back to you know where +we wrote this and how we try to justify + + align:start position:0% +we wrote this and how we try to justify + + + align:start position:0% +we wrote this and how we try to justify +this and you work your way through it + + align:start position:0% +this and you work your way through it + + + align:start position:0% +this and you work your way through it +you will see that NDS can be analyzed + + align:start position:0% +you will see that NDS can be analyzed + + + align:start position:0% +you will see that NDS can be analyzed +the same way + + align:start position:0% +the same way + + + align:start position:0% +the same way +so n is + + align:start position:0% +so n is + + + align:start position:0% +so n is +T rotated 90° + + align:start position:0% + + + + align:start position:0% + +clockwise so that tells us that + + align:start position:0% +clockwise so that tells us that + + + align:start position:0% +clockwise so that tells us that +NDS is so how do we rotate a vector by + + align:start position:0% +NDS is so how do we rotate a vector by + + + align:start position:0% +NDS is so how do we rotate a vector by +90° well we swap the two components and + + align:start position:0% +90° well we swap the two components and + + + align:start position:0% +90° well we swap the two components and +we put a minus sign so swap them you + + align:start position:0% +we put a minus sign so swap them you + + + align:start position:0% +we put a minus sign so swap them you +have Dy and DX and you have to be + + align:start position:0% +have Dy and DX and you have to be + + + align:start position:0% +have Dy and DX and you have to be +careful where to put the minus sign well + + align:start position:0% +careful where to put the minus sign well + + + align:start position:0% +careful where to put the minus sign well +it's if you're doing it clockwise it's + + align:start position:0% +it's if you're doing it clockwise it's + + + align:start position:0% +it's if you're doing it clockwise it's +in front of + + align:start position:0% + + + + align:start position:0% + +DX well actually let me just convince + + align:start position:0% +DX well actually let me just convince + + + align:start position:0% +DX well actually let me just convince +you quickly by you know let's say we + + align:start position:0% +you quickly by you know let's say we + + + align:start position:0% +you quickly by you know let's say we +have a small piece of + + align:start position:0% +have a small piece of + + + align:start position:0% +have a small piece of +C so if we do T Delta s okay T Delta s + + align:start position:0% +C so if we do T Delta s okay T Delta s + + + align:start position:0% +C so if we do T Delta s okay T Delta s +that's also Vector Dr if you Delta R + + align:start position:0% +that's also Vector Dr if you Delta R + + + align:start position:0% +that's also Vector Dr if you Delta R +sorry that's going to be just you know + + align:start position:0% +sorry that's going to be just you know + + + align:start position:0% +sorry that's going to be just you know +the vector that goes along the + + align:start position:0% +the vector that goes along the + + + align:start position:0% +the vector that goes along the +curve it's given by this so its + + align:start position:0% +curve it's given by this so its + + + align:start position:0% +curve it's given by this so its +components will be indeed the change in + + align:start position:0% +components will be indeed the change in + + + align:start position:0% +components will be indeed the change in +X Delta X and the change in y Delta y + + align:start position:0% + + + + align:start position:0% + +and now if I want to get n Delta + + align:start position:0% +and now if I want to get n Delta + + + align:start position:0% +and now if I want to get n Delta +s well I claim now it's perfectly valid + + align:start position:0% +s well I claim now it's perfectly valid + + + align:start position:0% +s well I claim now it's perfectly valid +and rigorous to just rotate that by 90° + + align:start position:0% +and rigorous to just rotate that by 90° + + + align:start position:0% +and rigorous to just rotate that by 90° +so I lost my red + + align:start position:0% +so I lost my red + + + align:start position:0% +so I lost my red +choke here it + + align:start position:0% + + + + align:start position:0% + +is so if I want to rotate this by 90 + + align:start position:0% +is so if I want to rotate this by 90 + + + align:start position:0% +is so if I want to rotate this by 90 +degrees + + align:start position:0% + + + + align:start position:0% + +clockwise then the X component will + + align:start position:0% +clockwise then the X component will + + + align:start position:0% +clockwise then the X component will +become the same as the old y + + align:start position:0% +become the same as the old y + + + align:start position:0% +become the same as the old y +component and the Y component will be + + align:start position:0% +component and the Y component will be + + + align:start position:0% +component and the Y component will be +minus Delta X and then you take the + + align:start position:0% +minus Delta X and then you take the + + + align:start position:0% +minus Delta X and then you take the +limit when the segment becomes shorter + + align:start position:0% +limit when the segment becomes shorter + + + align:start position:0% +limit when the segment becomes shorter +and shorter and that's how you can + + align:start position:0% +and shorter and that's how you can + + + align:start position:0% +and shorter and that's how you can +justify + + align:start position:0% +justify + + + align:start position:0% +justify +this + + align:start position:0% +this + + + align:start position:0% +this +okay so that's the key to Computing + + align:start position:0% +okay so that's the key to Computing + + + align:start position:0% +okay so that's the key to Computing +things in practice it means actually you + + align:start position:0% +things in practice it means actually you + + + align:start position:0% +things in practice it means actually you +already know how to compute line + + align:start position:0% +already know how to compute line + + + align:start position:0% +already know how to compute line +integrals for + + align:start position:0% + + + + align:start position:0% + +flux let me just + + align:start position:0% +flux let me just + + + align:start position:0% +flux let me just +write it + + align:start position:0% + + + + align:start position:0% + +explicitly so let's say that our Vector + + align:start position:0% +explicitly so let's say that our Vector + + + align:start position:0% +explicitly so let's say that our Vector +field has two components so let me just + + align:start position:0% +field has two components so let me just + + + align:start position:0% +field has two components so let me just +confuse you a little bit and not call + + align:start position:0% +confuse you a little bit and not call + + + align:start position:0% +confuse you a little bit and not call +them M and N for this time just to + + align:start position:0% +them M and N for this time just to + + + align:start position:0% +them M and N for this time just to +stress out you know just to stress the + + align:start position:0% +stress out you know just to stress the + + + align:start position:0% +stress out you know just to stress the +fact that we doing a different line + + align:start position:0% +fact that we doing a different line + + + align:start position:0% +fact that we doing a different line +integral so let me call them p and Q for + + align:start position:0% + + + + align:start position:0% + +now then the line + + align:start position:0% +now then the line + + + align:start position:0% +now then the line +integral of f. n + + align:start position:0% +integral of f. n + + + align:start position:0% +integral of f. n +DS will be the line integral of well + + align:start position:0% +DS will be the line integral of well + + + align:start position:0% +DS will be the line integral of well +PQ + + align:start position:0% +PQ + + + align:start position:0% +PQ +product uh where is it + + align:start position:0% +product uh where is it + + + align:start position:0% +product uh where is it +Dy netive + + align:start position:0% +Dy netive + + + align:start position:0% +Dy netive +DX so that will be the integral of + + align:start position:0% +DX so that will be the integral of + + + align:start position:0% +DX so that will be the integral of +qdx plus P well I'm running out of space + + align:start position:0% +qdx plus P well I'm running out of space + + + align:start position:0% +qdx plus P well I'm running out of space +here it's integral along c of Q DX Plus + + align:start position:0% +here it's integral along c of Q DX Plus + + + align:start position:0% +here it's integral along c of Q DX Plus +pdy + + align:start position:0% + + + + align:start position:0% + +okay and from that point onwards you + + align:start position:0% +okay and from that point onwards you + + + align:start position:0% +okay and from that point onwards you +just do it the usual way namely you you + + align:start position:0% +just do it the usual way namely you you + + + align:start position:0% +just do it the usual way namely you you +know remember here you have two + + align:start position:0% +know remember here you have two + + + align:start position:0% +know remember here you have two +variables X and Y but you're integrating + + align:start position:0% +variables X and Y but you're integrating + + + align:start position:0% +variables X and Y but you're integrating +along a curve so if you're integrating + + align:start position:0% +along a curve so if you're integrating + + + align:start position:0% +along a curve so if you're integrating +along a curve X and Y are related they + + align:start position:0% +along a curve X and Y are related they + + + align:start position:0% +along a curve X and Y are related they +depend on each other or maybe on some + + align:start position:0% +depend on each other or maybe on some + + + align:start position:0% +depend on each other or maybe on some +other parameter like T or Theta or + + align:start position:0% +other parameter like T or Theta or + + + align:start position:0% +other parameter like T or Theta or +whatever so you express everything in + + align:start position:0% +whatever so you express everything in + + + align:start position:0% +whatever so you express everything in +terms of a single variable and then you + + align:start position:0% +terms of a single variable and then you + + + align:start position:0% +terms of a single variable and then you +do a usual single integral + + align:start position:0% + + + + align:start position:0% + +okay any questions about + + align:start position:0% + + + + align:start position:0% + +that I see a lot of confused faces so + + align:start position:0% +that I see a lot of confused faces so + + + align:start position:0% +that I see a lot of confused faces so +maybe I shouldn't have called my + + align:start position:0% +maybe I shouldn't have called my + + + align:start position:0% +maybe I shouldn't have called my +components p and Q so + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so if you + + align:start position:0% + + + + align:start position:0% + +prefer okay so if you if you you know if + + align:start position:0% +prefer okay so if you if you you know if + + + align:start position:0% +prefer okay so if you if you you know if +you're really sentimentally attached to + + align:start position:0% +you're really sentimentally attached to + + + align:start position:0% +you're really sentimentally attached to +M and N + + align:start position:0% +M and N + + + align:start position:0% +M and N +then this new line + + align:start position:0% +then this new line + + + align:start position:0% +then this new line +integral becomes the integral of minus n + + align:start position:0% +integral becomes the integral of minus n + + + align:start position:0% +integral becomes the integral of minus n +DX + + align:start position:0% +DX + + + align:start position:0% +DX +plus + + align:start position:0% + + + + align:start position:0% + +mdy okay so you know if a problem tells + + align:start position:0% +mdy okay so you know if a problem tells + + + align:start position:0% +mdy okay so you know if a problem tells +you compute flux instead of saying + + align:start position:0% +you compute flux instead of saying + + + align:start position:0% +you compute flux instead of saying +compute work the only thing you change + + align:start position:0% +compute work the only thing you change + + + align:start position:0% +compute work the only thing you change +is instead of doing MDX plus n d y you + + align:start position:0% +is instead of doing MDX plus n d y you + + + align:start position:0% +is instead of doing MDX plus n d y you +do minus ndx plus + + align:start position:0% +do minus ndx plus + + + align:start position:0% +do minus ndx plus +mdy and I'm sorry to say I don't have + + align:start position:0% +mdy and I'm sorry to say I don't have + + + align:start position:0% +mdy and I'm sorry to say I don't have +any good way of helping you remember + + align:start position:0% +any good way of helping you remember + + + align:start position:0% +any good way of helping you remember +which one of the two gets the minus sign + + align:start position:0% +which one of the two gets the minus sign + + + align:start position:0% +which one of the two gets the minus sign +so you know you just have to remember + + align:start position:0% +so you know you just have to remember + + + align:start position:0% +so you know you just have to remember +this formula by heart that's the only + + align:start position:0% +this formula by heart that's the only + + + align:start position:0% +this formula by heart that's the only +way I + + align:start position:0% + + + + align:start position:0% + +know well I mean can try to you know go + + align:start position:0% +know well I mean can try to you know go + + + align:start position:0% +know well I mean can try to you know go +through this argument again but it's I + + align:start position:0% +through this argument again but it's I + + + align:start position:0% +through this argument again but it's I +mean it's really best if you just + + align:start position:0% +mean it's really best if you just + + + align:start position:0% +mean it's really best if you just +remember that + + align:start position:0% + + + + align:start position:0% + +formula + + align:start position:0% +formula + + + align:start position:0% +formula +okay so I'm not going to do an example + + align:start position:0% +okay so I'm not going to do an example + + + align:start position:0% +okay so I'm not going to do an example +because we already know how to do line + + align:start position:0% +because we already know how to do line + + + align:start position:0% +because we already know how to do line +integrals okay but hopefully you will + + align:start position:0% +integrals okay but hopefully you will + + + align:start position:0% +integrals okay but hopefully you will +get to see one at least in recitation on + + align:start position:0% + + + + align:start position:0% + +Monday okay so that's all pretty good + + align:start position:0% +Monday okay so that's all pretty good + + + align:start position:0% +Monday okay so that's all pretty good +let me tell you now what if I have to + + align:start position:0% +let me tell you now what if I have to + + + align:start position:0% +let me tell you now what if I have to +compute flux along a closed curve and I + + align:start position:0% +compute flux along a closed curve and I + + + align:start position:0% +compute flux along a closed curve and I +don't want to compute + + align:start position:0% + + + + align:start position:0% + +it + + align:start position:0% +it + + + align:start position:0% +it +so well remember in the case of work we + + align:start position:0% +so well remember in the case of work we + + + align:start position:0% +so well remember in the case of work we +had grein theorum we saw yesterday grein + + align:start position:0% +had grein theorum we saw yesterday grein + + + align:start position:0% +had grein theorum we saw yesterday grein +theorum Let's us replace a line integral + + align:start position:0% +theorum Let's us replace a line integral + + + align:start position:0% +theorum Let's us replace a line integral +along a closed curve by a double + + align:start position:0% +along a closed curve by a double + + + align:start position:0% +along a closed curve by a double +integral well here it's the same we have + + align:start position:0% +integral well here it's the same we have + + + align:start position:0% +integral well here it's the same we have +a line integral along a curve we should + + align:start position:0% +a line integral along a curve we should + + + align:start position:0% +a line integral along a curve we should +be able if it's a closed curve we should + + align:start position:0% +be able if it's a closed curve we should + + + align:start position:0% +be able if it's a closed curve we should +be able to replace it by a double + + align:start position:0% +be able to replace it by a double + + + align:start position:0% +be able to replace it by a double +integral so there is a vers of green + + align:start position:0% +integral so there is a vers of green + + + align:start position:0% +integral so there is a vers of green +theorem for + + align:start position:0% + + + + align:start position:0% + +flux and you'll see it's not more scary + + align:start position:0% +flux and you'll see it's not more scary + + + align:start position:0% +flux and you'll see it's not more scary +than the other one + + align:start position:0% +than the other one + + + align:start position:0% +than the other one +it's perhaps less scary or perhaps just + + align:start position:0% +it's perhaps less scary or perhaps just + + + align:start position:0% +it's perhaps less scary or perhaps just +as scary or just as not scary depending + + align:start position:0% +as scary or just as not scary depending + + + align:start position:0% +as scary or just as not scary depending +on how you feel about it but + + align:start position:0% +on how you feel about it but + + + align:start position:0% +on how you feel about it but +it's it works pretty much the same + + align:start position:0% +it's it works pretty much the same + + + align:start position:0% +it's it works pretty much the same +way okay so what does green spor for + + align:start position:0% +way okay so what does green spor for + + + align:start position:0% +way okay so what does green spor for +C so it says if C is a curve that + + align:start position:0% +C so it says if C is a curve that + + + align:start position:0% +C so it says if C is a curve that +encloses or region + + align:start position:0% + + + + align:start position:0% + +R + + align:start position:0% + + + + align:start position:0% + +counterclockwise and if I have a vector + + align:start position:0% +counterclockwise and if I have a vector + + + align:start position:0% +counterclockwise and if I have a vector +field that's defined everywhere not just + + align:start position:0% +field that's defined everywhere not just + + + align:start position:0% +field that's defined everywhere not just +on C but also inside so also on r + + align:start position:0% + + + + align:start position:0% + +defined well and differentiable and so + + align:start position:0% +defined well and differentiable and so + + + align:start position:0% +defined well and differentiable and so +on in R well maybe I should give names + + align:start position:0% +on in R well maybe I should give names + + + align:start position:0% +on in R well maybe I should give names +to the + + align:start position:0% +to the + + + align:start position:0% +to the +components so if you'll forgive me for a + + align:start position:0% +components so if you'll forgive me for a + + + align:start position:0% +components so if you'll forgive me for a +second I will still use p and Q for now + + align:start position:0% +second I will still use p and Q for now + + + align:start position:0% +second I will still use p and Q for now +you'll see why + + align:start position:0% +you'll see why + + + align:start position:0% +you'll see why +um is defined and differentiable in + + align:start position:0% + + + + align:start position:0% + +R then I can + + align:start position:0% + + + + align:start position:0% + +actually replace the line integral for + + align:start position:0% +actually replace the line integral for + + + align:start position:0% +actually replace the line integral for +flux by a double integral over R of some + + align:start position:0% +flux by a double integral over R of some + + + align:start position:0% +flux by a double integral over R of some +function and that function is called the + + align:start position:0% +function and that function is called the + + + align:start position:0% +function and that function is called the +Divergence of + + align:start position:0% +Divergence of + + + align:start position:0% +Divergence of +f + + align:start position:0% +f + + + align:start position:0% +f +da okay + + align:start position:0% +da okay + + + align:start position:0% +da okay +so this is the + + align:start position:0% + + + + align:start position:0% + +Divergence of f + + align:start position:0% +Divergence of f + + + align:start position:0% +Divergence of f +and I have to Define for you what this + + align:start position:0% +and I have to Define for you what this + + + align:start position:0% +and I have to Define for you what this +guy + + align:start position:0% + + + + align:start position:0% + +is so the Divergence of a vector field + + align:start position:0% +is so the Divergence of a vector field + + + align:start position:0% +is so the Divergence of a vector field +with components p and Q is just P subx + + align:start position:0% +with components p and Q is just P subx + + + align:start position:0% +with components p and Q is just P subx +plus Q sub + + align:start position:0% +plus Q sub + + + align:start position:0% +plus Q sub +y so this one is actually easier to + + align:start position:0% +y so this one is actually easier to + + + align:start position:0% +y so this one is actually easier to +remember than Cur right because you just + + align:start position:0% +remember than Cur right because you just + + + align:start position:0% +remember than Cur right because you just +take the X component take it special + + align:start position:0% +take the X component take it special + + + align:start position:0% +take the X component take it special +with respect to X take the Y component + + align:start position:0% +with respect to X take the Y component + + + align:start position:0% +with respect to X take the Y component +take it special respect to Y and add + + align:start position:0% +take it special respect to Y and add + + + align:start position:0% +take it special respect to Y and add +them together no signs no switching + + align:start position:0% +them together no signs no switching + + + align:start position:0% +them together no signs no switching +things + + align:start position:0% +things + + + align:start position:0% +things +around this one is pretty + + align:start position:0% +around this one is pretty + + + align:start position:0% +around this one is pretty +straightforward okay so the picture + + align:start position:0% +straightforward okay so the picture + + + align:start position:0% +straightforward okay so the picture +again is if I have my curve C going + + align:start position:0% +again is if I have my curve C going + + + align:start position:0% +again is if I have my curve C going +counterclockwise around the Orion + + align:start position:0% +counterclockwise around the Orion + + + align:start position:0% +counterclockwise around the Orion +R and I want to find the flux of some + + align:start position:0% +R and I want to find the flux of some + + + align:start position:0% +R and I want to find the flux of some +Vector field + + align:start position:0% +Vector field + + + align:start position:0% +Vector field +F that you know is everywhere in here + + align:start position:0% + + + + align:start position:0% + +so maybe some parts of C will contribute + + align:start position:0% +so maybe some parts of C will contribute + + + align:start position:0% +so maybe some parts of C will contribute +positively some parts will contribute + + align:start position:0% +positively some parts will contribute + + + align:start position:0% +positively some parts will contribute +negatively way just to reiterate what I + + align:start position:0% +negatively way just to reiterate what I + + + align:start position:0% +negatively way just to reiterate what I +said positively here means because we + + align:start position:0% +said positively here means because we + + + align:start position:0% +said positively here means because we +going counterclockwise the normal Vector + + align:start position:0% +going counterclockwise the normal Vector + + + align:start position:0% +going counterclockwise the normal Vector +points out of the + + align:start position:0% +points out of the + + + align:start position:0% +points out of the +region okay so this guy here is the + + align:start position:0% +region okay so this guy here is the + + + align:start position:0% +region okay so this guy here is the +flux + + align:start position:0% +flux + + + align:start position:0% +flux +out of R through C + + align:start position:0% + + + + align:start position:0% + +okay so that's the formula any questions + + align:start position:0% +okay so that's the formula any questions + + + align:start position:0% +okay so that's the formula any questions +about what the statement says or how to + + align:start position:0% +about what the statement says or how to + + + align:start position:0% +about what the statement says or how to +use it + + align:start position:0% + + + + align:start position:0% + +concretely + + align:start position:0% +concretely + + + align:start position:0% +concretely +no okay so it's pretty similar to Green + + align:start position:0% +no okay so it's pretty similar to Green + + + align:start position:0% +no okay so it's pretty similar to Green +theorem for work so actually I should + + align:start position:0% + + + + align:start position:0% + +say so maybe I should see this is green + + align:start position:0% +say so maybe I should see this is green + + + align:start position:0% +say so maybe I should see this is green +this is called Green + + align:start position:0% +this is called Green + + + align:start position:0% +this is called Green +sporum in normal form also so not that + + align:start position:0% +sporum in normal form also so not that + + + align:start position:0% +sporum in normal form also so not that +the other one is abnormal but just that + + align:start position:0% +the other one is abnormal but just that + + + align:start position:0% +the other one is abnormal but just that +you + + align:start position:0% +you + + + align:start position:0% +you +know the old + + align:start position:0% +know the old + + + align:start position:0% +know the old +one for work was you could say in + + align:start position:0% +one for work was you could say in + + + align:start position:0% +one for work was you could say in +tangential + + align:start position:0% + + + + align:start position:0% + +form that just means well green theorem + + align:start position:0% +form that just means well green theorem + + + align:start position:0% +form that just means well green theorem +as seen yesterday was for the line + + align:start position:0% +as seen yesterday was for the line + + + align:start position:0% +as seen yesterday was for the line +integral F.T DS integrating the tangent + + align:start position:0% +integral F.T DS integrating the tangent + + + align:start position:0% +integral F.T DS integrating the tangent +component of T of f + + align:start position:0% +component of T of f + + + align:start position:0% +component of T of f +sorry um the one today is for + + align:start position:0% +sorry um the one today is for + + + align:start position:0% +sorry um the one today is for +integrating the normal component of + + align:start position:0% +integrating the normal component of + + + align:start position:0% +integrating the normal component of +f okay let's prove this + + align:start position:0% +f okay let's prove this + + + align:start position:0% +f okay let's prove this +so good news it's much easier to prove + + align:start position:0% +so good news it's much easier to prove + + + align:start position:0% +so good news it's much easier to prove +than the one we did yesterday because + + align:start position:0% +than the one we did yesterday because + + + align:start position:0% +than the one we did yesterday because +we're just going to show that it's the + + align:start position:0% +we're just going to show that it's the + + + align:start position:0% +we're just going to show that it's the +same thing just using different + + align:start position:0% +same thing just using different + + + align:start position:0% +same thing just using different +notations + + align:start position:0% + + + + align:start position:0% + +okay so how do I prove + + align:start position:0% +okay so how do I prove + + + align:start position:0% +okay so how do I prove +it well maybe actually it would help if + + align:start position:0% +it well maybe actually it would help if + + + align:start position:0% +it well maybe actually it would help if +first before proving it I actually + + align:start position:0% +first before proving it I actually + + + align:start position:0% +first before proving it I actually +rewrite what it means in + + align:start position:0% +rewrite what it means in + + + align:start position:0% +rewrite what it means in +components + + align:start position:0% + + + + align:start position:0% + +okay so we said the line integral of f. + + align:start position:0% +okay so we said the line integral of f. + + + align:start position:0% +okay so we said the line integral of f. +n DS is actually the line integral + + align:start position:0% +n DS is actually the line integral + + + align:start position:0% +n DS is actually the line integral +of Q DX plus P + + align:start position:0% +of Q DX plus P + + + align:start position:0% +of Q DX plus P +Dy right and we want to show that this + + align:start position:0% +Dy right and we want to show that this + + + align:start position:0% +Dy right and we want to show that this +is equal to the double integral of p + + align:start position:0% +is equal to the double integral of p + + + align:start position:0% +is equal to the double integral of p +subx plus Q sub y + + align:start position:0% + + + + align:start position:0% + +da so this looks a lot like you know + + align:start position:0% +da so this looks a lot like you know + + + align:start position:0% +da so this looks a lot like you know +this is really one of the features of + + align:start position:0% +this is really one of the features of + + + align:start position:0% +this is really one of the features of +green theorum no matter which form it's + + align:start position:0% +green theorum no matter which form it's + + + align:start position:0% +green theorum no matter which form it's +in it relates a line integral to a + + align:start position:0% +in it relates a line integral to a + + + align:start position:0% +in it relates a line integral to a +double + + align:start position:0% +double + + + align:start position:0% +double +integral so let's just try to see if we + + align:start position:0% +integral so let's just try to see if we + + + align:start position:0% +integral so let's just try to see if we +can reduce it to the one we had + + align:start position:0% +can reduce it to the one we had + + + align:start position:0% +can reduce it to the one we had +yesterday + + align:start position:0% +yesterday + + + align:start position:0% +yesterday +so you know let me + + align:start position:0% +so you know let me + + + align:start position:0% +so you know let me +forget what these things mean physically + + align:start position:0% +forget what these things mean physically + + + align:start position:0% +forget what these things mean physically +and just focus on the math on the math + + align:start position:0% +and just focus on the math on the math + + + align:start position:0% +and just focus on the math on the math +it's a line integral of something DX + + align:start position:0% +it's a line integral of something DX + + + align:start position:0% +it's a line integral of something DX +Plus something Dy so let's call this guy + + align:start position:0% +Plus something Dy so let's call this guy + + + align:start position:0% +Plus something Dy so let's call this guy +M and let's call this guy + + align:start position:0% +M and let's call this guy + + + align:start position:0% +M and let's call this guy +n okay so let m = q and N equal + + align:start position:0% +n okay so let m = q and N equal + + + align:start position:0% +n okay so let m = q and N equal +p + + align:start position:0% +p + + + align:start position:0% +p +then I know well this guy here + + align:start position:0% +then I know well this guy here + + + align:start position:0% +then I know well this guy here +becomes integral of M DX plus n + + align:start position:0% +becomes integral of M DX plus n + + + align:start position:0% +becomes integral of M DX plus n +Dy and I know from + + align:start position:0% +Dy and I know from + + + align:start position:0% +Dy and I know from +yesterday what this is equal to namely + + align:start position:0% +yesterday what this is equal to namely + + + align:start position:0% +yesterday what this is equal to namely +using the tangential form of green + + align:start position:0% +using the tangential form of green + + + align:start position:0% +using the tangential form of green +theoren for work this is the double + + align:start position:0% +theoren for work this is the double + + + align:start position:0% +theoren for work this is the double +integral of Cur of this guy so that's NX + + align:start position:0% +integral of Cur of this guy so that's NX + + + align:start position:0% +integral of Cur of this guy so that's NX +minus n y + + align:start position:0% +minus n y + + + align:start position:0% +minus n y +da but now let's think about what this + + align:start position:0% +da but now let's think about what this + + + align:start position:0% +da but now let's think about what this +is in terms of M and N well we + + align:start position:0% +is in terms of M and N well we + + + align:start position:0% +is in terms of M and N well we +said that m is negative Q so this is + + align:start position:0% +said that m is negative Q so this is + + + align:start position:0% +said that m is negative Q so this is +negative m + + align:start position:0% +negative m + + + align:start position:0% +negative m +y and we say p is the same as n so this + + align:start position:0% +y and we say p is the same as n so this + + + align:start position:0% +y and we say p is the same as n so this +is n + + align:start position:0% +is n + + + align:start position:0% +is n +x so C just by renaming the + + align:start position:0% +x so C just by renaming the + + + align:start position:0% +x so C just by renaming the +components I go from one form to the + + align:start position:0% +components I go from one form to the + + + align:start position:0% +components I go from one form to the +other one so it's really the same + + align:start position:0% +other one so it's really the same + + + align:start position:0% +other one so it's really the same +theorem that's why it's also called + + align:start position:0% +theorem that's why it's also called + + + align:start position:0% +theorem that's why it's also called +Green theorem but the way we think about + + align:start position:0% +Green theorem but the way we think about + + + align:start position:0% +Green theorem but the way we think about +it when we use it is different because + + align:start position:0% +it when we use it is different because + + + align:start position:0% +it when we use it is different because +one of them computes the work done by a + + align:start position:0% +one of them computes the work done by a + + + align:start position:0% +one of them computes the work done by a +force along a closed curve the other one + + align:start position:0% +force along a closed curve the other one + + + align:start position:0% +force along a closed curve the other one +computes the flux maybe of a velocity + + align:start position:0% +computes the flux maybe of a velocity + + + align:start position:0% +computes the flux maybe of a velocity +field out of a closed region out of out + + align:start position:0% +field out of a closed region out of out + + + align:start position:0% +field out of a closed region out of out +of a region + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +questions yes so + + align:start position:0% + + + + align:start position:0% + +we yeah that's correct so if you're + + align:start position:0% +we yeah that's correct so if you're + + + align:start position:0% +we yeah that's correct so if you're +trying to compute you know a line + + align:start position:0% +trying to compute you know a line + + + align:start position:0% +trying to compute you know a line +integral for flux you see it just + + align:start position:0% +integral for flux you see it just + + + align:start position:0% +integral for flux you see it just +becomes wait where did I put it so the + + align:start position:0% +becomes wait where did I put it so the + + + align:start position:0% +becomes wait where did I put it so the +line integral for flux just becomes this + + align:start position:0% +line integral for flux just becomes this + + + align:start position:0% +line integral for flux just becomes this +and once you're here you know how to + + align:start position:0% +and once you're here you know how to + + + align:start position:0% +and once you're here you know how to +compute that kind of + + align:start position:0% +compute that kind of + + + align:start position:0% +compute that kind of +thing um you know the double integral + + align:start position:0% +thing um you know the double integral + + + align:start position:0% +thing um you know the double integral +side there's no even there's not even + + align:start position:0% +side there's no even there's not even + + + align:start position:0% +side there's no even there's not even +any kind of renaming to do you know how + + align:start position:0% +any kind of renaming to do you know how + + + align:start position:0% +any kind of renaming to do you know how +to compute a double integral of a + + align:start position:0% +to compute a double integral of a + + + align:start position:0% +to compute a double integral of a +function and this is just a particular + + align:start position:0% +function and this is just a particular + + + align:start position:0% +function and this is just a particular +kind of function that you get out of a + + align:start position:0% +kind of function that you get out of a + + + align:start position:0% +kind of function that you get out of a +vector field but it's any fun you know + + align:start position:0% +vector field but it's any fun you know + + + align:start position:0% +vector field but it's any fun you know +it's like any function the way you would + + align:start position:0% +it's like any function the way you would + + + align:start position:0% +it's like any function the way you would +evaluate these double integrals is just + + align:start position:0% +evaluate these double integrals is just + + + align:start position:0% +evaluate these double integrals is just +the usual way you have a function of X + + align:start position:0% +the usual way you have a function of X + + + align:start position:0% +the usual way you have a function of X +and Y you have a region and you set up + + align:start position:0% +and Y you have a region and you set up + + + align:start position:0% +and Y you have a region and you set up +the bounds for the iterated + + align:start position:0% +the bounds for the iterated + + + align:start position:0% +the bounds for the iterated +integral quiet please there's a lot of + + align:start position:0% +integral quiet please there's a lot of + + + align:start position:0% +integral quiet please there's a lot of +people talking + + align:start position:0% +people talking + + + align:start position:0% +people talking +but + + align:start position:0% +but + + + align:start position:0% +but +okay so the way you would evaluate the + + align:start position:0% +okay so the way you would evaluate the + + + align:start position:0% +okay so the way you would evaluate the +double integrals is really the usual Way + + align:start position:0% +double integrals is really the usual Way + + + align:start position:0% +double integrals is really the usual Way +by slicing the region and setting up the + + align:start position:0% +by slicing the region and setting up the + + + align:start position:0% +by slicing the region and setting up the +bounds for iterated integrals in you + + align:start position:0% +bounds for iterated integrals in you + + + align:start position:0% +bounds for iterated integrals in you +know DX Dy or dydx or maybe Rd Rd Theta + + align:start position:0% +know DX Dy or dydx or maybe Rd Rd Theta + + + align:start position:0% +know DX Dy or dydx or maybe Rd Rd Theta +or whatever you + + align:start position:0% +or whatever you + + + align:start position:0% +or whatever you +want um so in fact in terms of computing + + align:start position:0% +want um so in fact in terms of computing + + + align:start position:0% +want um so in fact in terms of computing +integrals we just have two sets of + + align:start position:0% +integrals we just have two sets of + + + align:start position:0% +integrals we just have two sets of +skills one is setting up evaluating + + align:start position:0% +skills one is setting up evaluating + + + align:start position:0% +skills one is setting up evaluating +double integrals the other one is + + align:start position:0% +double integrals the other one is + + + align:start position:0% +double integrals the other one is +setting up evaluating line integrals and + + align:start position:0% +setting up evaluating line integrals and + + + align:start position:0% +setting up evaluating line integrals and +whether these line integrals or double + + align:start position:0% +whether these line integrals or double + + + align:start position:0% +whether these line integrals or double +integrals are representing a work a flux + + align:start position:0% +integrals are representing a work a flux + + + align:start position:0% +integrals are representing a work a flux +integral of a curl whatever the way that + + align:start position:0% +integral of a curl whatever the way that + + + align:start position:0% +integral of a curl whatever the way that +we actually compute them is the + + align:start position:0% +we actually compute them is the + + + align:start position:0% +we actually compute them is the +same + + align:start position:0% +same + + + align:start position:0% +same +okay okay let's do an + + align:start position:0% +okay okay let's do an + + + align:start position:0% +okay okay let's do an +example oh by the way no so first + + align:start position:0% + + + + align:start position:0% + +sorry so this renaming here see that's + + align:start position:0% +sorry so this renaming here see that's + + + align:start position:0% +sorry so this renaming here see that's +why actually I called my components p + + align:start position:0% +why actually I called my components p + + + align:start position:0% +why actually I called my components p +and Q because the argument would have + + align:start position:0% +and Q because the argument would have + + + align:start position:0% +and Q because the argument would have +gotten very messy if I had told you oh + + align:start position:0% +gotten very messy if I had told you oh + + + align:start position:0% +gotten very messy if I had told you oh +well now I call m n and I call n minus M + + align:start position:0% +well now I call m n and I call n minus M + + + align:start position:0% +well now I call m n and I call n minus M +and so on uh but now that we're done you + + align:start position:0% +and so on uh but now that we're done you + + + align:start position:0% +and so on uh but now that we're done you +now that we're full with this if you + + align:start position:0% +now that we're full with this if you + + + align:start position:0% +now that we're full with this if you +still like m&n + + align:start position:0% +still like m&n + + + align:start position:0% +still like m&n +better you know then what this + + align:start position:0% + + + + align:start position:0% + +says then the form you know the + + align:start position:0% +says then the form you know the + + + align:start position:0% +says then the form you know the +formulation of green theorem in this + + align:start position:0% +formulation of green theorem in this + + + align:start position:0% +formulation of green theorem in this +language is just integral of minus n DX + + align:start position:0% +language is just integral of minus n DX + + + align:start position:0% +language is just integral of minus n DX +plus + + align:start position:0% +plus + + + align:start position:0% +plus +mdy is double integral over R of MX plus + + align:start position:0% +mdy is double integral over R of MX plus + + + align:start position:0% +mdy is double integral over R of MX plus +NY + + align:start position:0% + + + + align:start position:0% + +da + + align:start position:0% +da + + + align:start position:0% +da +okay okay so now let's do an example + + align:start position:0% +okay okay so now let's do an example + + + align:start position:0% +okay okay so now let's do an example +let's look at this picture again you + + align:start position:0% +let's look at this picture again you + + + align:start position:0% +let's look at this picture again you +know the Flux Of x i + y j out of a + + align:start position:0% +know the Flux Of x i + y j out of a + + + align:start position:0% +know the Flux Of x i + y j out of a +circle of radius + + align:start position:0% + + + + align:start position:0% + +a so we did the calculation directly + + align:start position:0% +a so we did the calculation directly + + + align:start position:0% +a so we did the calculation directly +using geometry and it wasn't all that + + align:start position:0% +using geometry and it wasn't all that + + + align:start position:0% +using geometry and it wasn't all that +bad but let's see what green does for us + + align:start position:0% + + + + align:start position:0% + +here okay so example let's take the same + + align:start position:0% +here okay so example let's take the same + + + align:start position:0% +here okay so example let's take the same +example as last time um so x i + y j + + align:start position:0% +example as last time um so x i + y j + + + align:start position:0% +example as last time um so x i + y j +through C the + + align:start position:0% +through C the + + + align:start position:0% +through C the +circle of radius a + + align:start position:0% + + + + align:start position:0% + +counterclockwise okay so how do we do + + align:start position:0% +counterclockwise okay so how do we do + + + align:start position:0% +counterclockwise okay so how do we do +how do we set up grein theorum well + + align:start position:0% +how do we set up grein theorum well + + + align:start position:0% +how do we set up grein theorum well +let's first figure + + align:start position:0% +let's first figure + + + align:start position:0% +let's first figure +out the Divergence of + + align:start position:0% +out the Divergence of + + + align:start position:0% +out the Divergence of +f that's you + + align:start position:0% +f that's you + + + align:start position:0% +f that's you +so so the Divergence of this field I + + align:start position:0% +so so the Divergence of this field I + + + align:start position:0% +so so the Divergence of this field I +take the X component which is X and I + + align:start position:0% +take the X component which is X and I + + + align:start position:0% +take the X component which is X and I +take it special respect to X and then I + + align:start position:0% +take it special respect to X and then I + + + align:start position:0% +take it special respect to X and then I +do the same with the Y + + align:start position:0% +do the same with the Y + + + align:start position:0% +do the same with the Y +component and I will get 1 + 1 equals 2 + + align:start position:0% +component and I will get 1 + 1 equals 2 + + + align:start position:0% +component and I will get 1 + 1 equals 2 +okay so the diverence of this field is + + align:start position:0% +okay so the diverence of this field is + + + align:start position:0% +okay so the diverence of this field is +two now green theorem tells us that the + + align:start position:0% +two now green theorem tells us that the + + + align:start position:0% +two now green theorem tells us that the +flux out of this region is going to be + + align:start position:0% +flux out of this region is going to be + + + align:start position:0% +flux out of this region is going to be +the double + + align:start position:0% +the double + + + align:start position:0% +the double +integral of 2 Da + + align:start position:0% +integral of 2 Da + + + align:start position:0% +integral of 2 Da +where what is r now well R is the region + + align:start position:0% +where what is r now well R is the region + + + align:start position:0% +where what is r now well R is the region +enclosed by C so if C is the circle R is + + align:start position:0% +enclosed by C so if C is the circle R is + + + align:start position:0% +enclosed by C so if C is the circle R is +the dis of radius + + align:start position:0% +the dis of radius + + + align:start position:0% +the dis of radius +a so of course we can compute it but we + + align:start position:0% +a so of course we can compute it but we + + + align:start position:0% +a so of course we can compute it but we +don't have to because double integral of + + align:start position:0% +don't have to because double integral of + + + align:start position:0% +don't have to because double integral of +2 Da is just twice the double integral + + align:start position:0% +2 Da is just twice the double integral + + + align:start position:0% +2 Da is just twice the double integral +of Da so it's twice the + + align:start position:0% +of Da so it's twice the + + + align:start position:0% +of Da so it's twice the +area of R and we know the area of a + + align:start position:0% +area of R and we know the area of a + + + align:start position:0% +area of R and we know the area of a +circle of radius a that's Pi a s so + + align:start position:0% +circle of radius a that's Pi a s so + + + align:start position:0% +circle of radius a that's Pi a s so +that's 2 pi a s + + align:start position:0% +that's 2 pi a s + + + align:start position:0% +that's 2 pi a s +here that's the same answer that we got + + align:start position:0% +here that's the same answer that we got + + + align:start position:0% +here that's the same answer that we got +directly which is good + + align:start position:0% +directly which is good + + + align:start position:0% +directly which is good +news so now we can even do better let's + + align:start position:0% +news so now we can even do better let's + + + align:start position:0% +news so now we can even do better let's +say that my circle is not at the origin + + align:start position:0% +say that my circle is not at the origin + + + align:start position:0% +say that my circle is not at the origin +you know let's say that it's out + + align:start position:0% +you know let's say that it's out + + + align:start position:0% +you know let's say that it's out +here well then it becomes harder to + + align:start position:0% +here well then it becomes harder to + + + align:start position:0% +here well then it becomes harder to +calculate the flux directly you know and + + align:start position:0% +calculate the flux directly you know and + + + align:start position:0% +calculate the flux directly you know and +it's harder even to guess exactly what + + align:start position:0% +it's harder even to guess exactly what + + + align:start position:0% +it's harder even to guess exactly what +will happen because on this side here + + align:start position:0% +will happen because on this side here + + + align:start position:0% +will happen because on this side here +well the vector field will go into the + + align:start position:0% +well the vector field will go into the + + + align:start position:0% +well the vector field will go into the +region so the contribution to flux will + + align:start position:0% +region so the contribution to flux will + + + align:start position:0% +region so the contribution to flux will +be negative here + + align:start position:0% +be negative here + + + align:start position:0% +be negative here +well here it will be positive because + + align:start position:0% +well here it will be positive because + + + align:start position:0% +well here it will be positive because +it's going out of the region so there's + + align:start position:0% +it's going out of the region so there's + + + align:start position:0% +it's going out of the region so there's +positive there's negative terms well it + + align:start position:0% +positive there's negative terms well it + + + align:start position:0% +positive there's negative terms well it +looks like positive should win because + + align:start position:0% +looks like positive should win because + + + align:start position:0% +looks like positive should win because +here the vector field is much larger + + align:start position:0% +here the vector field is much larger + + + align:start position:0% +here the vector field is much larger +than over + + align:start position:0% +than over + + + align:start position:0% +than over +there um but you know + + align:start position:0% +there um but you know + + + align:start position:0% +there um but you know +Computing short of computing it we won't + + align:start position:0% +Computing short of computing it we won't + + + align:start position:0% +Computing short of computing it we won't +actually know what it is so if you want + + align:start position:0% +actually know what it is so if you want + + + align:start position:0% +actually know what it is so if you want +to do it by direct calculation then you + + align:start position:0% +to do it by direct calculation then you + + + align:start position:0% +to do it by direct calculation then you +have to parameterize this circle and + + align:start position:0% +have to parameterize this circle and + + + align:start position:0% +have to parameterize this circle and +figure out you know what the line + + align:start position:0% +figure out you know what the line + + + align:start position:0% +figure out you know what the line +integral will be but if you use green + + align:start position:0% +integral will be but if you use green + + + align:start position:0% +integral will be but if you use green +theorem well we never used the fact it's + + align:start position:0% +theorem well we never used the fact it's + + + align:start position:0% +theorem well we never used the fact it's +the circle of radius a at the + + align:start position:0% +the circle of radius a at the + + + align:start position:0% +the circle of radius a at the +origin right it's true actually for any + + align:start position:0% +origin right it's true actually for any + + + align:start position:0% +origin right it's true actually for any +closed curve that the flux out of it is + + align:start position:0% +closed curve that the flux out of it is + + + align:start position:0% +closed curve that the flux out of it is +going to be twice the area of the region + + align:start position:0% +going to be twice the area of the region + + + align:start position:0% +going to be twice the area of the region +inside so it will still be 2 pi a s even + + align:start position:0% +inside so it will still be 2 pi a s even + + + align:start position:0% +inside so it will still be 2 pi a s even +if my circle is anywhere else in the + + align:start position:0% +if my circle is anywhere else in the + + + align:start position:0% +if my circle is anywhere else in the +plane so you know if I had asked you the + + align:start position:0% +plane so you know if I had asked you the + + + align:start position:0% +plane so you know if I had asked you the +TR question where do you want to place + + align:start position:0% +TR question where do you want to place + + + align:start position:0% +TR question where do you want to place +this circle so that the flux is the + + align:start position:0% +this circle so that the flux is the + + + align:start position:0% +this circle so that the flux is the +largest well the answer is actually it + + align:start position:0% +largest well the answer is actually it + + + align:start position:0% +largest well the answer is actually it +doesn't + + align:start position:0% +doesn't + + + align:start position:0% +doesn't +matter okay + + align:start position:0% + + + + align:start position:0% + +now + + align:start position:0% +now + + + align:start position:0% +now +let's just finish quickly by answering a + + align:start position:0% +let's just finish quickly by answering a + + + align:start position:0% +let's just finish quickly by answering a +question that some of you I'm sure must + + align:start position:0% +question that some of you I'm sure must + + + align:start position:0% +question that some of you I'm sure must +have which is what does Divergence mean + + align:start position:0% +have which is what does Divergence mean + + + align:start position:0% +have which is what does Divergence mean +what does it measure right I mean we say + + align:start position:0% +what does it measure right I mean we say + + + align:start position:0% +what does it measure right I mean we say +it for curl curl measures how much + + align:start position:0% +it for curl curl measures how much + + + align:start position:0% +it for curl curl measures how much +things are rotating somehow so what does + + align:start position:0% +things are rotating somehow so what does + + + align:start position:0% +things are rotating somehow so what does +the Divergence + + align:start position:0% +the Divergence + + + align:start position:0% +the Divergence +mean well the answer is Divergence mean + + align:start position:0% +mean well the answer is Divergence mean + + + align:start position:0% +mean well the answer is Divergence mean +Divergence measures how much things are + + align:start position:0% +Divergence measures how much things are + + + align:start position:0% +Divergence measures how much things are +diverging okay + + align:start position:0% +diverging okay + + + align:start position:0% +diverging okay +that's uh let's be + + align:start position:0% +that's uh let's be + + + align:start position:0% +that's uh let's be +more explicit + + align:start position:0% + + + + align:start position:0% + +so so interpretation of + + align:start position:0% + + + + align:start position:0% + +Divergence actually you can think of it + + align:start position:0% +Divergence actually you can think of it + + + align:start position:0% +Divergence actually you can think of it +you know imagine that so what do I want + + align:start position:0% +you know imagine that so what do I want + + + align:start position:0% +you know imagine that so what do I want +to say first so if you take a vector + + align:start position:0% +to say first so if you take a vector + + + align:start position:0% +to say first so if you take a vector +field that just like maybe you know + + align:start position:0% +field that just like maybe you know + + + align:start position:0% +field that just like maybe you know +that's a constant Vector field where + + align:start position:0% +that's a constant Vector field where + + + align:start position:0% +that's a constant Vector field where +everything just translates then there's + + align:start position:0% +everything just translates then there's + + + align:start position:0% +everything just translates then there's +no Divergence involved because the + + align:start position:0% +no Divergence involved because the + + + align:start position:0% +no Divergence involved because the +derivatives will be zero if you take the + + align:start position:0% +derivatives will be zero if you take the + + + align:start position:0% +derivatives will be zero if you take the +guy that rotates things around you'll + + align:start position:0% +guy that rotates things around you'll + + + align:start position:0% +guy that rotates things around you'll +also compute and find zero for + + align:start position:0% +also compute and find zero for + + + align:start position:0% +also compute and find zero for +Divergence so this is not sensitive to + + align:start position:0% +Divergence so this is not sensitive to + + + align:start position:0% +Divergence so this is not sensitive to +translation motions where everything + + align:start position:0% +translation motions where everything + + + align:start position:0% +translation motions where everything +moves together or to rotation motions + + align:start position:0% +moves together or to rotation motions + + + align:start position:0% +moves together or to rotation motions +but instead it's sensitive to expanding + + align:start position:0% +but instead it's sensitive to expanding + + + align:start position:0% +but instead it's sensitive to expanding +motions so possible answer is that it + + align:start position:0% +motions so possible answer is that it + + + align:start position:0% +motions so possible answer is that it +measures how much + + align:start position:0% + + + + align:start position:0% + +the + + align:start position:0% +the + + + align:start position:0% +the +flow is + + align:start position:0% + + + + align:start position:0% + +expanding areas okay so if you you know + + align:start position:0% +expanding areas okay so if you you know + + + align:start position:0% +expanding areas okay so if you you know +if you imagine this flow that we have + + align:start position:0% +if you imagine this flow that we have + + + align:start position:0% +if you imagine this flow that we have +here on that picture things are moving + + align:start position:0% +here on that picture things are moving + + + align:start position:0% +here on that picture things are moving +away from the origin and they you know + + align:start position:0% +away from the origin and they you know + + + align:start position:0% +away from the origin and they you know +fill out the plane if you imagine this + + align:start position:0% +fill out the plane if you imagine this + + + align:start position:0% +fill out the plane if you imagine this +fluid flowing out there it's occupying + + align:start position:0% +fluid flowing out there it's occupying + + + align:start position:0% +fluid flowing out there it's occupying +more and more + + align:start position:0% +more and more + + + align:start position:0% +more and more +space and so that's what it means to + + align:start position:0% +space and so that's what it means to + + + align:start position:0% +space and so that's what it means to +have positive Divergence if you took the + + align:start position:0% +have positive Divergence if you took the + + + align:start position:0% +have positive Divergence if you took the +opposite Vector field that contracts + + align:start position:0% +opposite Vector field that contracts + + + align:start position:0% +opposite Vector field that contracts +everything to the + + align:start position:0% +everything to the + + + align:start position:0% +everything to the +origin that would have negative + + align:start position:0% +origin that would have negative + + + align:start position:0% +origin that would have negative +diverence so that's a good way to think + + align:start position:0% +diverence so that's a good way to think + + + align:start position:0% +diverence so that's a good way to think +about it if you're thinking of a gas + + align:start position:0% +about it if you're thinking of a gas + + + align:start position:0% +about it if you're thinking of a gas +maybe that can expand to fill out more + + align:start position:0% +maybe that can expand to fill out more + + + align:start position:0% +maybe that can expand to fill out more +volume if you're thinking of water well + + align:start position:0% +volume if you're thinking of water well + + + align:start position:0% +volume if you're thinking of water well +water doesn't really shrink or expand so + + align:start position:0% +water doesn't really shrink or expand so + + + align:start position:0% +water doesn't really shrink or expand so +the fact that it's taking more and more + + align:start position:0% +the fact that it's taking more and more + + + align:start position:0% +the fact that it's taking more and more +space actually means that there's more + + align:start position:0% +space actually means that there's more + + + align:start position:0% +space actually means that there's more +and more water so the other way to think + + align:start position:0% +and more water so the other way to think + + + align:start position:0% +and more water so the other way to think +about it is Divergence is the source + + align:start position:0% + + + + align:start position:0% + +rate so it's the amount of fluid that's + + align:start position:0% +rate so it's the amount of fluid that's + + + align:start position:0% +rate so it's the amount of fluid that's +being inserted into the system that's + + align:start position:0% +being inserted into the system that's + + + align:start position:0% +being inserted into the system that's +being pumped into the system per unit + + align:start position:0% +being pumped into the system per unit + + + align:start position:0% +being pumped into the system per unit +time per unit + + align:start position:0% + + + + align:start position:0% + +area per unit time and per unit area so + + align:start position:0% +area per unit time and per unit area so + + + align:start position:0% +area per unit time and per unit area so +what div f equals 2 here means is that + + align:start position:0% +what div f equals 2 here means is that + + + align:start position:0% +what div f equals 2 here means is that +here you have actually matter being + + align:start position:0% +here you have actually matter being + + + align:start position:0% +here you have actually matter being +created or being pumped into the system + + align:start position:0% +created or being pumped into the system + + + align:start position:0% +created or being pumped into the system +so that you know you have more and more + + align:start position:0% +so that you know you have more and more + + + align:start position:0% +so that you know you have more and more +water filling more and more space as it + + align:start position:0% +water filling more and more space as it + + + align:start position:0% +water filling more and more space as it +flows but actually diverence is not too + + align:start position:0% +flows but actually diverence is not too + + + align:start position:0% +flows but actually diverence is not too +just at the origin it's two everywhere + + align:start position:0% +just at the origin it's two everywhere + + + align:start position:0% +just at the origin it's two everywhere +so in fact to have this you need to have + + align:start position:0% +so in fact to have this you need to have + + + align:start position:0% +so in fact to have this you need to have +a system of pumps that actually is + + align:start position:0% +a system of pumps that actually is + + + align:start position:0% +a system of pumps that actually is +inserting water absolutely everywhere + + align:start position:0% +inserting water absolutely everywhere + + + align:start position:0% +inserting water absolutely everywhere +uniformly that's the only way to do this + + align:start position:0% +uniformly that's the only way to do this + + + align:start position:0% +uniformly that's the only way to do this +I mean if you imagine that you just have + + align:start position:0% +I mean if you imagine that you just have + + + align:start position:0% +I mean if you imagine that you just have +one you know spring at the origin then + + align:start position:0% +one you know spring at the origin then + + + align:start position:0% +one you know spring at the origin then +sure water will flow out but as you go + + align:start position:0% +sure water will flow out but as you go + + + align:start position:0% +sure water will flow out but as you go +further and further away it will do so + + align:start position:0% +further and further away it will do so + + + align:start position:0% +further and further away it will do so +more and more slowly while here it's + + align:start position:0% +more and more slowly while here it's + + + align:start position:0% +more and more slowly while here it's +flowing away faster and faster and that + + align:start position:0% +flowing away faster and faster and that + + + align:start position:0% +flowing away faster and faster and that +means you know everywhere actually + + align:start position:0% +means you know everywhere actually + + + align:start position:0% +means you know everywhere actually +you're still pumping more water into + + align:start position:0% +you're still pumping more water into + + + align:start position:0% +you're still pumping more water into +it um so that's what Divergence measures \ No newline at end of file diff --git a/_bTZbn7M2Hc.txt b/_bTZbn7M2Hc.txt new file mode 100644 index 0000000000000000000000000000000000000000..b02ce9b05b41f2d25115b4d468867acfd9da71d5 --- /dev/null +++ b/_bTZbn7M2Hc.txt @@ -0,0 +1,1394 @@ +align:start position:0% + +all right so let's get now the state and + + align:start position:0% +all right so let's get now the state and + + + align:start position:0% +all right so let's get now the state and +one so I want to make a general remark + + align:start position:0% +one so I want to make a general remark + + + align:start position:0% +one so I want to make a general remark +you have an equation like this and we + + align:start position:0% +you have an equation like this and we + + + align:start position:0% +you have an equation like this and we +want to solve it it's a vector equation + + align:start position:0% +want to solve it it's a vector equation + + + align:start position:0% +want to solve it it's a vector equation +operator and a vector equal number and a + + align:start position:0% +operator and a vector equal number and a + + + align:start position:0% +operator and a vector equal number and a +vector am or operator and a vector to + + align:start position:0% +vector am or operator and a vector to + + + align:start position:0% +vector am or operator and a vector to +make sure you have solved it when you + + align:start position:0% +make sure you have solved it when you + + + align:start position:0% +make sure you have solved it when you +have a vector equation you must make + + align:start position:0% +have a vector equation you must make + + + align:start position:0% +have a vector equation you must make +sure that every component you can write + + align:start position:0% +sure that every component you can write + + + align:start position:0% +sure that every component you can write +a vector in equation in the firm vector + + align:start position:0% +a vector in equation in the firm vector + + + align:start position:0% +a vector in equation in the firm vector +equals zero and then you must make sure + + align:start position:0% +equals zero and then you must make sure + + + align:start position:0% +equals zero and then you must make sure +that every component of the vector is + + align:start position:0% +that every component of the vector is + + + align:start position:0% +that every component of the vector is +zero what we did here is we found what + + align:start position:0% +zero what we did here is we found what + + + align:start position:0% +zero what we did here is we found what +happens when I look at the component + + align:start position:0% +happens when I look at the component + + + align:start position:0% +happens when I look at the component +along and zero and I figure out that + + align:start position:0% +along and zero and I figure out that + + + align:start position:0% +along and zero and I figure out that +whoops this equation when I look at the + + align:start position:0% +whoops this equation when I look at the + + + align:start position:0% +whoops this equation when I look at the +component along and zero tells me what + + align:start position:0% +component along and zero tells me what + + + align:start position:0% +component along and zero tells me what +the energy is so the rest of the + + align:start position:0% +the energy is so the rest of the + + + align:start position:0% +the energy is so the rest of the +information of this equation arises when + + align:start position:0% +information of this equation arises when + + + align:start position:0% +information of this equation arises when +I look at it along the components on the + + align:start position:0% +I look at it along the components on the + + + align:start position:0% +I look at it along the components on the +other states not in zero but the K + + align:start position:0% +other states not in zero but the K + + + align:start position:0% +other states not in zero but the K +states that we introduced from the + + align:start position:0% +states that we introduced from the + + + align:start position:0% +states that we introduced from the +beginning the KZ rows that run with from + + align:start position:0% +beginning the KZ rows that run with from + + + align:start position:0% +beginning the KZ rows that run with from +1 to infinity so what we're gonna do is + + align:start position:0% +1 to infinity so what we're gonna do is + + + align:start position:0% +1 to infinity so what we're gonna do is +take that original this second equation + + align:start position:0% +take that original this second equation + + + align:start position:0% +take that original this second equation +and form K 0 H 0 minus e + 0 + 1 is + + align:start position:0% +and form K 0 H 0 minus e + 0 + 1 is + + + align:start position:0% +and form K 0 H 0 minus e + 0 + 1 is +equal to K 0 e n1 minus Delta H + 0 so I + + align:start position:0% +equal to K 0 e n1 minus Delta H + 0 so I + + + align:start position:0% +equal to K 0 e n1 minus Delta H + 0 so I +now took the same equation and I put an + + align:start position:0% +now took the same equation and I put an + + + align:start position:0% +now took the same equation and I put an +inner product with K 0 and I say look K + + align:start position:0% +inner product with K 0 and I say look K + + + align:start position:0% +inner product with K 0 and I say look K +will be different from n because when we + + align:start position:0% +will be different from n because when we + + + align:start position:0% +will be different from n because when we +put k equal to n that already we've done + + align:start position:0% +put k equal to n that already we've done + + + align:start position:0% +put k equal to n that already we've done +and we've learned all about it and in + + align:start position:0% +and we've learned all about it and in + + + align:start position:0% +and we've learned all about it and in +fact and one didn't appear the state + + align:start position:0% +fact and one didn't appear the state + + + align:start position:0% +fact and one didn't appear the state +that we wanted didn't appear at all so + + align:start position:0% +that we wanted didn't appear at all so + + + align:start position:0% +that we wanted didn't appear at all so +now we do this with arbitrary K and we + + align:start position:0% +now we do this with arbitrary K and we + + + align:start position:0% +now we do this with arbitrary K and we +need to figure out what this gives so so + + align:start position:0% +need to figure out what this gives so so + + + align:start position:0% +need to figure out what this gives so so +you have to look at these things and try + + align:start position:0% +you have to look at these things and try + + + align:start position:0% +you have to look at these things and try +to remember a little the definitions + + align:start position:0% +to remember a little the definitions + + + align:start position:0% +to remember a little the definitions +we've put so H 0 we know what it gives + + align:start position:0% +we've put so H 0 we know what it gives + + + align:start position:0% +we've put so H 0 we know what it gives +them K 0 it gives you a number the + + align:start position:0% +them K 0 it gives you a number the + + + align:start position:0% +them K 0 it gives you a number the +energy of that state so this is another + + align:start position:0% +energy of that state so this is another + + + align:start position:0% +energy of that state so this is another +number so that's great this simplifies + + align:start position:0% +number so that's great this simplifies + + + align:start position:0% +number so that's great this simplifies +this to e K 0 minus e and 0 times the + + align:start position:0% +this to e K 0 minus e and 0 times the + + + align:start position:0% +this to e K 0 minus e and 0 times the +overlap of K is 0 with N 1 that's the + + align:start position:0% +overlap of K is 0 with N 1 that's the + + + align:start position:0% +overlap of K is 0 with N 1 that's the +left-hand side how about the right-hand + + align:start position:0% +left-hand side how about the right-hand + + + align:start position:0% +left-hand side how about the right-hand +side all right let's see what this is + + align:start position:0% +side all right let's see what this is + + + align:start position:0% +side all right let's see what this is +first term the Ian 1 is a number so I + + align:start position:0% +first term the Ian 1 is a number so I + + + align:start position:0% +first term the Ian 1 is a number so I +must ask myself is what happens when K 0 + + align:start position:0% +must ask myself is what happens when K 0 + + + align:start position:0% +must ask myself is what happens when K 0 +meets n 0 well those are our original or + + align:start position:0% +meets n 0 well those are our original or + + + align:start position:0% +meets n 0 well those are our original or +third normal States and we said that K + + align:start position:0% +third normal States and we said that K + + + align:start position:0% +third normal States and we said that K +is different from n so this term is 0 + + align:start position:0% +is different from n so this term is 0 + + + align:start position:0% +is different from n so this term is 0 +with the en 1 this is a number and these + + align:start position:0% +with the en 1 this is a number and these + + + align:start position:0% +with the en 1 this is a number and these +two states are orthogonal so this term + + align:start position:0% +two states are orthogonal so this term + + + align:start position:0% +two states are orthogonal so this term +gives you a 0 not because this number is + + align:start position:0% +gives you a 0 not because this number is + + + align:start position:0% +gives you a 0 not because this number is +0 but because the overlap is 0 and I get + + align:start position:0% +0 but because the overlap is 0 and I get + + + align:start position:0% +0 but because the overlap is 0 and I get +here minus K 0 Delta H and 0 and it's a + + align:start position:0% +here minus K 0 Delta H and 0 and it's a + + + align:start position:0% +here minus K 0 Delta H and 0 and it's a +good notation to call this to save + + align:start position:0% +good notation to call this to save + + + align:start position:0% +good notation to call this to save +writing Delta H K and + + align:start position:0% + + + + align:start position:0% + +it's a good name for it it's the matrix + + align:start position:0% +it's a good name for it it's the matrix + + + align:start position:0% +it's a good name for it it's the matrix +k KN 'the element of the matrix Delta H + + align:start position:0% +k KN 'the element of the matrix Delta H + + + align:start position:0% +k KN 'the element of the matrix Delta H +and this is a number so I can solve k 0 + + align:start position:0% +and this is a number so I can solve k 0 + + + align:start position:0% +and this is a number so I can solve k 0 +and 1 is equal to minus Delta H K and / + + align:start position:0% +and 1 is equal to minus Delta H K and / + + + align:start position:0% +and 1 is equal to minus Delta H K and / +EK 0 minus e n 0 and this is true for + + align:start position:0% +EK 0 minus e n 0 and this is true for + + + align:start position:0% +EK 0 minus e n 0 and this is true for +every k different from n and here we + + align:start position:0% +every k different from n and here we + + + align:start position:0% +every k different from n and here we +find for the first time our energy + + align:start position:0% +find for the first time our energy + + + align:start position:0% +find for the first time our energy +denominators these energy denominators + + align:start position:0% +denominators these energy denominators + + + align:start position:0% +denominators these energy denominators +are the things that are gonna make life + + align:start position:0% +are the things that are gonna make life + + + align:start position:0% +are the things that are gonna make life +interesting and difficult and it answers + + align:start position:0% +interesting and difficult and it answers + + + align:start position:0% +interesting and difficult and it answers +the question already that if you had the + + align:start position:0% +the question already that if you had the + + + align:start position:0% +the question already that if you had the +generate states there would be some K + + align:start position:0% +generate states there would be some K + + + align:start position:0% +generate states there would be some K +states that have the same energy as this + + align:start position:0% +states that have the same energy as this + + + align:start position:0% +states that have the same energy as this +one and this blows up and this is + + align:start position:0% +one and this blows up and this is + + + align:start position:0% +one and this blows up and this is +unsolvable for this component so you + + align:start position:0% +unsolvable for this component so you + + + align:start position:0% +unsolvable for this component so you +start getting difficult ease if you have + + align:start position:0% +start getting difficult ease if you have + + + align:start position:0% +start getting difficult ease if you have +degeneracies as long as every K state + + align:start position:0% +degeneracies as long as every K state + + + align:start position:0% +degeneracies as long as every K state +all the other states of the spectrum + + align:start position:0% +all the other states of the spectrum + + + align:start position:0% +all the other states of the spectrum +have different energy from en never mind + + align:start position:0% +have different energy from en never mind + + + align:start position:0% +have different energy from en never mind +if the other states are degenerate + + align:start position:0% +if the other states are degenerate + + + align:start position:0% +if the other states are degenerate +they're not degenerate with a state you + + align:start position:0% +they're not degenerate with a state you + + + align:start position:0% +they're not degenerate with a state you +care you care just about one state now + + align:start position:0% +care you care just about one state now + + + align:start position:0% +care you care just about one state now +the nth state and if that's non + + align:start position:0% +the nth state and if that's non + + + align:start position:0% +the nth state and if that's non +degenerate all these denominators are + + align:start position:0% +degenerate all these denominators are + + + align:start position:0% +degenerate all these denominators are +non zero and you're okay so here is the + + align:start position:0% +non zero and you're okay so here is the + + + align:start position:0% +non zero and you're okay so here is the +solution for this thing now I can write + + align:start position:0% + + + + align:start position:0% + +the expressions + + align:start position:0% +the expressions + + + align:start position:0% +the expressions +for the state and the energy so let me + + align:start position:0% +for the state and the energy so let me + + + align:start position:0% +for the state and the energy so let me +do it so I have this n1 like that you + + align:start position:0% +do it so I have this n1 like that you + + + align:start position:0% +do it so I have this n1 like that you +can say the following let me do this + + align:start position:0% +can say the following let me do this + + + align:start position:0% +can say the following let me do this +very deliberately first and one is equal + + align:start position:0% +very deliberately first and one is equal + + + align:start position:0% +very deliberately first and one is equal +to the sum over all K of K naught K + + align:start position:0% +to the sum over all K of K naught K + + + align:start position:0% +to the sum over all K of K naught K +naught and 1 this is the resolution of + + align:start position:0% +naught and 1 this is the resolution of + + + align:start position:0% +naught and 1 this is the resolution of +the identity formula that's the unit + + align:start position:0% +the identity formula that's the unit + + + align:start position:0% +the identity formula that's the unit +operator you can always do that and now + + align:start position:0% +operator you can always do that and now + + + align:start position:0% +operator you can always do that and now +you know that the state N 1 is + + align:start position:0% +you know that the state N 1 is + + + align:start position:0% +you know that the state N 1 is +orthogonal to n 0 so this becomes the + + align:start position:0% +orthogonal to n 0 so this becomes the + + + align:start position:0% +orthogonal to n 0 so this becomes the +sum over K different from n because for + + align:start position:0% +sum over K different from n because for + + + align:start position:0% +sum over K different from n because for +k equal to n these are orthogonal of K + + align:start position:0% +k equal to n these are orthogonal of K + + + align:start position:0% +k equal to n these are orthogonal of K +naught K naught and 1 and that's what we + + align:start position:0% +naught K naught and 1 and that's what we + + + align:start position:0% +naught K naught and 1 and that's what we +calculated here so so what did we get + + align:start position:0% +calculated here so so what did we get + + + align:start position:0% +calculated here so so what did we get +there for the state and 1 I can + + align:start position:0% +there for the state and 1 I can + + + align:start position:0% +there for the state and 1 I can +substitute what we had there it's the + + align:start position:0% +substitute what we had there it's the + + + align:start position:0% +substitute what we had there it's the +sum from k different from n of K naught + + align:start position:0% + + + + align:start position:0% + +Delta H and K over e K naught minus E + + align:start position:0% +Delta H and K over e K naught minus E + + + align:start position:0% +Delta H and K over e K naught minus E +and not that's N 1 I should have a minus + + align:start position:0% +and not that's N 1 I should have a minus + + + align:start position:0% +and not that's N 1 I should have a minus +sign the minus sign is there at state N + + align:start position:0% +sign the minus sign is there at state N + + + align:start position:0% +sign the minus sign is there at state N + + align:start position:0% + + + + align:start position:0% + +so the state and one is gets it is a + + align:start position:0% +so the state and one is gets it is a + + + align:start position:0% +so the state and one is gets it is a +complicated correction it gets a little + + align:start position:0% +complicated correction it gets a little + + + align:start position:0% +complicated correction it gets a little +component from every other state of the + + align:start position:0% +component from every other state of the + + + align:start position:0% +component from every other state of the +spectrum and the coefficient depends on + + align:start position:0% +spectrum and the coefficient depends on + + + align:start position:0% +spectrum and the coefficient depends on +the matrix element of your state with + + align:start position:0% +the matrix element of your state with + + + align:start position:0% +the matrix element of your state with +the state you're contributing with so + + align:start position:0% +the state you're contributing with so + + + align:start position:0% +the state you're contributing with so +you have the state n here and all the + + align:start position:0% +you have the state n here and all the + + + align:start position:0% +you have the state n here and all the +other states here the amount of this + + align:start position:0% +other states here the amount of this + + + align:start position:0% +other states here the amount of this +state K that enters into the correction + + align:start position:0% +state K that enters into the correction + + + align:start position:0% +state K that enters into the correction +is proportional to the matrix element + + align:start position:0% +is proportional to the matrix element + + + align:start position:0% +is proportional to the matrix element +between m and K if the matrix element is + + align:start position:0% +between m and K if the matrix element is + + + align:start position:0% +between m and K if the matrix element is +zero that state does not contribute here + + align:start position:0% +zero that state does not contribute here + + + align:start position:0% +zero that state does not contribute here +and then there is the energy denominator + + align:start position:0% +and then there is the energy denominator + + + align:start position:0% +and then there is the energy denominator +as well so we're getting to the end of + + align:start position:0% +as well so we're getting to the end of + + + align:start position:0% +as well so we're getting to the end of +this calculation there's one more thing + + align:start position:0% +this calculation there's one more thing + + + align:start position:0% +this calculation there's one more thing +one can do which is to find and so I'm + + align:start position:0% +one can do which is to find and so I'm + + + align:start position:0% +one can do which is to find and so I'm +starting to wrap up this but still an + + align:start position:0% +starting to wrap up this but still an + + + align:start position:0% +starting to wrap up this but still an +important step what we have to do I'll + + align:start position:0% +important step what we have to do I'll + + + align:start position:0% +important step what we have to do I'll +get the second order energy correction + + align:start position:0% +get the second order energy correction + + + align:start position:0% +get the second order energy correction +what is our second order energy + + align:start position:0% +what is our second order energy + + + align:start position:0% +what is our second order energy +correction our second order energy + + align:start position:0% +correction our second order energy + + + align:start position:0% +correction our second order energy +correction can be found from the formula + + align:start position:0% +correction can be found from the formula + + + align:start position:0% +correction can be found from the formula +on that blackboard e + 2 we already + + align:start position:0% +on that blackboard e + 2 we already + + + align:start position:0% +on that blackboard e + 2 we already +found the first order energy correction + + align:start position:0% +found the first order energy correction + + + align:start position:0% +found the first order energy correction +which I happen to have erased it right + + align:start position:0% +which I happen to have erased it right + + + align:start position:0% +which I happen to have erased it right +now it was there en 2 is obtained by + + align:start position:0% +now it was there en 2 is obtained by + + + align:start position:0% +now it was there en 2 is obtained by +doing n 0 Delta H times N 1 which we + + align:start position:0% +doing n 0 Delta H times N 1 which we + + + align:start position:0% +doing n 0 Delta H times N 1 which we +already know so I must do n 0 Delta H on + + align:start position:0% +already know so I must do n 0 Delta H on + + + align:start position:0% +already know so I must do n 0 Delta H on +that so look what you get you get minus + + align:start position:0% +that so look what you get you get minus + + + align:start position:0% +that so look what you get you get minus +the sum over K different from n think of + + align:start position:0% +the sum over K different from n think of + + + align:start position:0% +the sum over K different from n think of +booting the N 0 and the Delta H they're + + align:start position:0% +booting the N 0 and the Delta H they're + + + align:start position:0% +booting the N 0 and the Delta H they're +all together it's a bra so far it's a + + align:start position:0% +all together it's a bra so far it's a + + + align:start position:0% +all together it's a bra so far it's a +Delta H and 0 it should go into N 1 but + + align:start position:0% +Delta H and 0 it should go into N 1 but + + + align:start position:0% +Delta H and 0 it should go into N 1 but +the only state in and 1 is K 0 so here + + align:start position:0% +the only state in and 1 is K 0 so here + + + align:start position:0% +the only state in and 1 is K 0 so here +half k0 and then we have delta h MK / EK + + align:start position:0% +half k0 and then we have delta h MK / EK + + + align:start position:0% +half k0 and then we have delta h MK / EK +0 minus e and 0 okay a little bit of + + align:start position:0% +0 minus e and 0 okay a little bit of + + + align:start position:0% +0 minus e and 0 okay a little bit of +work so what is this this is another + + align:start position:0% + + + + align:start position:0% + +matrix element this is the matrix I'm + + align:start position:0% +matrix element this is the matrix I'm + + + align:start position:0% +matrix element this is the matrix I'm +sorry here do I have a mistake yes I + + align:start position:0% +sorry here do I have a mistake yes I + + + align:start position:0% +sorry here do I have a mistake yes I +have KNI I copied it wrong it's K and + + align:start position:0% +have KNI I copied it wrong it's K and + + + align:start position:0% +have KNI I copied it wrong it's K and +yes yes so here I have Delta 8mk but + + align:start position:0% +yes yes so here I have Delta 8mk but + + + align:start position:0% +yes yes so here I have Delta 8mk but +Delta H and K is this + + align:start position:0% +Delta H and K is this + + + align:start position:0% +Delta H and K is this +if you complex conjugate if you complex + + align:start position:0% +if you complex conjugate if you complex + + + align:start position:0% +if you complex conjugate if you complex +on the Delta 8k and complex conjugate is + + align:start position:0% +on the Delta 8k and complex conjugate is + + + align:start position:0% +on the Delta 8k and complex conjugate is +K Delta H and complex conjugate which + + align:start position:0% +K Delta H and complex conjugate which + + + align:start position:0% +K Delta H and complex conjugate which +changes the order and Delta H which is + + align:start position:0% +changes the order and Delta H which is + + + align:start position:0% +changes the order and Delta H which is +hermitian K and that's Delta H and K so + + align:start position:0% +hermitian K and that's Delta H and K so + + + align:start position:0% +hermitian K and that's Delta H and K so +Delta H NK is equal to Delta H K and + + align:start position:0% +Delta H NK is equal to Delta H K and + + + align:start position:0% +Delta H NK is equal to Delta H K and +star and therefore the second order + + align:start position:0% +star and therefore the second order + + + align:start position:0% +star and therefore the second order +energy correction has a nice formula e + + align:start position:0% +energy correction has a nice formula e + + + align:start position:0% +energy correction has a nice formula e +n2 is equal to minus the sum over K + + align:start position:0% +n2 is equal to minus the sum over K + + + align:start position:0% +n2 is equal to minus the sum over K +different from n Delta H and K which is + + align:start position:0% +different from n Delta H and K which is + + + align:start position:0% +different from n Delta H and K which is +the star of that times this one so you + + align:start position:0% +the star of that times this one so you + + + align:start position:0% +the star of that times this one so you +get Delta H and K absolute value squared + + align:start position:0% +get Delta H and K absolute value squared + + + align:start position:0% +get Delta H and K absolute value squared +divided by e m EK n equals zero minus E + + align:start position:0% +divided by e m EK n equals zero minus E + + + align:start position:0% +divided by e m EK n equals zero minus E +and + + align:start position:0% + + + + align:start position:0% + +so we've done a lot of work with written + + align:start position:0% +so we've done a lot of work with written + + + align:start position:0% +so we've done a lot of work with written +the perturbation here is an answer so + + align:start position:0% +the perturbation here is an answer so + + + align:start position:0% +the perturbation here is an answer so +far we have n of lambda equal n 0 plus + + align:start position:0% +far we have n of lambda equal n 0 plus + + + align:start position:0% +far we have n of lambda equal n 0 plus +lambda N 1 and 1 has been calculated + + align:start position:0% +lambda N 1 and 1 has been calculated + + + align:start position:0% +lambda N 1 and 1 has been calculated +energies a and 0 plus lambda e in one + + align:start position:0% +energies a and 0 plus lambda e in one + + + align:start position:0% +energies a and 0 plus lambda e in one +that was calculated what was just Delta + + align:start position:0% +that was calculated what was just Delta + + + align:start position:0% +that was calculated what was just Delta +H in this state plus lambda squared e n2 + + align:start position:0% +H in this state plus lambda squared e n2 + + + align:start position:0% +H in this state plus lambda squared e n2 +which we have calculated so this is as + + align:start position:0% +which we have calculated so this is as + + + align:start position:0% +which we have calculated so this is as +far as we will do for non degenerate + + align:start position:0% +far as we will do for non degenerate + + + align:start position:0% +far as we will do for non degenerate +perturbation theory but we have found + + align:start position:0% +perturbation theory but we have found + + + align:start position:0% +perturbation theory but we have found +rather interesting formulas and we're + + align:start position:0% +rather interesting formulas and we're + + + align:start position:0% +rather interesting formulas and we're +going to spend half of next lecture + + align:start position:0% +going to spend half of next lecture + + + align:start position:0% +going to spend half of next lecture +trying to understand them better \ No newline at end of file diff --git a/_fWt9yHslDo.txt b/_fWt9yHslDo.txt new file mode 100644 index 0000000000000000000000000000000000000000..541c24914e45bf1b8385a6a60326238343002e5d --- /dev/null +++ b/_fWt9yHslDo.txt @@ -0,0 +1,4571 @@ +align:start position:0% + +so to start out I just wanted to mention + + align:start position:0% +so to start out I just wanted to mention + + + align:start position:0% +so to start out I just wanted to mention +we talk a lot about dogma + + align:start position:0% +we talk a lot about dogma + + + align:start position:0% +we talk a lot about dogma +in the lab so we talked about dogma + + align:start position:0% +in the lab so we talked about dogma + + + align:start position:0% +in the lab so we talked about dogma +right there's the central dogma which is + + align:start position:0% +right there's the central dogma which is + + + align:start position:0% +right there's the central dogma which is +DNA information flows from DNA to RNA to + + align:start position:0% +DNA information flows from DNA to RNA to + + + align:start position:0% +DNA information flows from DNA to RNA to +protein I'm gonna describe another dogma + + align:start position:0% +protein I'm gonna describe another dogma + + + align:start position:0% +protein I'm gonna describe another dogma +if you will which is that life starts as + + align:start position:0% +if you will which is that life starts as + + + align:start position:0% +if you will which is that life starts as +sort of a fertilized egg so you're get a + + align:start position:0% +sort of a fertilized egg so you're get a + + + align:start position:0% +sort of a fertilized egg so you're get a +fertilized egg and this fertilized egg + + align:start position:0% +fertilized egg and this fertilized egg + + + align:start position:0% +fertilized egg and this fertilized egg +which you see in the video up here + + align:start position:0% +which you see in the video up here + + + align:start position:0% +which you see in the video up here +undergoes development and as part of + + align:start position:0% +undergoes development and as part of + + + align:start position:0% +undergoes development and as part of +that development there is what is known + + align:start position:0% +that development there is what is known + + + align:start position:0% +that development there is what is known +as differentiation where cells acquire + + align:start position:0% +as differentiation where cells acquire + + + align:start position:0% +as differentiation where cells acquire +more specialized cell types so there's + + align:start position:0% +more specialized cell types so there's + + + align:start position:0% +more specialized cell types so there's +development and differentiation and this + + align:start position:0% +development and differentiation and this + + + align:start position:0% +development and differentiation and this +results in adult cell types that are + + align:start position:0% +results in adult cell types that are + + + align:start position:0% +results in adult cell types that are +known as differentiated so that results + + align:start position:0% +known as differentiated so that results + + + align:start position:0% +known as differentiated so that results +in differentiated / adult cell types + + align:start position:0% +in differentiated / adult cell types + + + align:start position:0% +in differentiated / adult cell types +with specialized functions and you see + + align:start position:0% +with specialized functions and you see + + + align:start position:0% +with specialized functions and you see +just a few of them up on the slide above + + align:start position:0% +just a few of them up on the slide above + + + align:start position:0% +just a few of them up on the slide above +there are in fact thousands of different + + align:start position:0% +there are in fact thousands of different + + + align:start position:0% +there are in fact thousands of different +sort of cell types that humans have but + + align:start position:0% +sort of cell types that humans have but + + + align:start position:0% +sort of cell types that humans have but +the dogma at least up until fairly + + align:start position:0% +the dogma at least up until fairly + + + align:start position:0% +the dogma at least up until fairly +recently in the past couple decades or + + align:start position:0% +recently in the past couple decades or + + + align:start position:0% +recently in the past couple decades or +so or at least before 1960 1950s is that + + align:start position:0% +so or at least before 1960 1950s is that + + + align:start position:0% +so or at least before 1960 1950s is that +this is unidirectional that you + + align:start position:0% +this is unidirectional that you + + + align:start position:0% +this is unidirectional that you +basically the development goes in one + + align:start position:0% +basically the development goes in one + + + align:start position:0% +basically the development goes in one +direction where you go from the + + align:start position:0% +direction where you go from the + + + align:start position:0% +direction where you go from the +fertilized egg to the differentiated + + align:start position:0% +fertilized egg to the differentiated + + + align:start position:0% +fertilized egg to the differentiated +adult cell types and so this state down + + align:start position:0% +adult cell types and so this state down + + + align:start position:0% +adult cell types and so this state down +here the differentiated adult cell types + + align:start position:0% +here the differentiated adult cell types + + + align:start position:0% +here the differentiated adult cell types +are fairly stable right + + align:start position:0% +are fairly stable right + + + align:start position:0% +are fairly stable right +I mean if you look at your neighbor you + + align:start position:0% +I mean if you look at your neighbor you + + + align:start position:0% +I mean if you look at your neighbor you +see they don't have muscle growing on + + align:start position:0% +see they don't have muscle growing on + + + align:start position:0% +see they don't have muscle growing on +the outside of their bodies right their + + align:start position:0% +the outside of their bodies right their + + + align:start position:0% +the outside of their bodies right their +skin cells taste skin cells and that is + + align:start position:0% +skin cells taste skin cells and that is + + + align:start position:0% +skin cells taste skin cells and that is +a relatively stable state okay now last + + align:start position:0% +a relatively stable state okay now last + + + align:start position:0% +a relatively stable state okay now last +week you learned about sort of a + + align:start position:0% +week you learned about sort of a + + + align:start position:0% +week you learned about sort of a +contradiction to the central dogma which + + align:start position:0% +contradiction to the central dogma which + + + align:start position:0% +contradiction to the central dogma which +is the behavior of retroviruses which + + align:start position:0% +is the behavior of retroviruses which + + + align:start position:0% +is the behavior of retroviruses which +which have reverse transcriptase which + + align:start position:0% +which have reverse transcriptase which + + + align:start position:0% +which have reverse transcriptase which +can sort of go backwards up this pathway + + align:start position:0% +can sort of go backwards up this pathway + + + align:start position:0% +can sort of go backwards up this pathway +where you can get DNA from RNA okay and + + align:start position:0% +where you can get DNA from RNA okay and + + + align:start position:0% +where you can get DNA from RNA okay and +today we're going to talk about how you + + align:start position:0% +today we're going to talk about how you + + + align:start position:0% +today we're going to talk about how you +can sort of overcome sort of this + + align:start position:0% +can sort of overcome sort of this + + + align:start position:0% +can sort of overcome sort of this +uni-directional path here and this is + + align:start position:0% +uni-directional path here and this is + + + align:start position:0% +uni-directional path here and this is +going to be what we will call + + align:start position:0% +going to be what we will call + + + align:start position:0% +going to be what we will call +reprogramming but first I want to talk + + align:start position:0% +reprogramming but first I want to talk + + + align:start position:0% +reprogramming but first I want to talk +about this differentiation process + + align:start position:0% +about this differentiation process + + + align:start position:0% +about this differentiation process +because it's important for us to + + align:start position:0% +because it's important for us to + + + align:start position:0% +because it's important for us to +understand this before we get into the + + align:start position:0% +understand this before we get into the + + + align:start position:0% +understand this before we get into the +reprogramming event and so the + + align:start position:0% +reprogramming event and so the + + + align:start position:0% +reprogramming event and so the +fertilized egg is capable of producing + + align:start position:0% +fertilized egg is capable of producing + + + align:start position:0% +fertilized egg is capable of producing +all of these different cell types okay + + align:start position:0% +all of these different cell types okay + + + align:start position:0% +all of these different cell types okay +so the fertilized egg will be known as + + align:start position:0% +so the fertilized egg will be known as + + + align:start position:0% +so the fertilized egg will be known as +totipotent meeting and has the potential + + align:start position:0% +totipotent meeting and has the potential + + + align:start position:0% +totipotent meeting and has the potential +to form all cell types and in over + + align:start position:0% +to form all cell types and in over + + + align:start position:0% +to form all cell types and in over +development this potency goes down such + + align:start position:0% +development this potency goes down such + + + align:start position:0% +development this potency goes down such +that when cells differentiate into their + + align:start position:0% +that when cells differentiate into their + + + align:start position:0% +that when cells differentiate into their +final adult form there's a much more + + align:start position:0% +final adult form there's a much more + + + align:start position:0% +final adult form there's a much more +limited repertoire of cell types that + + align:start position:0% +limited repertoire of cell types that + + + align:start position:0% +limited repertoire of cell types that +the cell can go into and one way of + + align:start position:0% +the cell can go into and one way of + + + align:start position:0% +the cell can go into and one way of +thinking about this is that if you think + + align:start position:0% +thinking about this is that if you think + + + align:start position:0% +thinking about this is that if you think +of this marble run here right the + + align:start position:0% +of this marble run here right the + + + align:start position:0% +of this marble run here right the +totipotent state is right at the top + + align:start position:0% +totipotent state is right at the top + + + align:start position:0% +totipotent state is right at the top +here right if I put a marble on the top + + align:start position:0% +here right if I put a marble on the top + + + align:start position:0% +here right if I put a marble on the top +here it has the potential of going into + + align:start position:0% +here it has the potential of going into + + + align:start position:0% +here it has the potential of going into +any of these three sort of different + + align:start position:0% +any of these three sort of different + + + align:start position:0% +any of these three sort of different +fates okay so this is the toady + + align:start position:0% +fates okay so this is the toady + + + align:start position:0% +fates okay so this is the toady +and state up at the top and you'll see + + align:start position:0% +and state up at the top and you'll see + + + align:start position:0% +and state up at the top and you'll see +these marbles will be able to go into + + align:start position:0% +these marbles will be able to go into + + + align:start position:0% +these marbles will be able to go into +any of these three different states here + + align:start position:0% +any of these three different states here + + + align:start position:0% +any of these three different states here +okay but you see how that marble went + + align:start position:0% +okay but you see how that marble went + + + align:start position:0% +okay but you see how that marble went +down on this path some marbles go down + + align:start position:0% +down on this path some marbles go down + + + align:start position:0% +down on this path some marbles go down +in this path and so you can think of + + align:start position:0% +in this path and so you can think of + + + align:start position:0% +in this path and so you can think of +cells going through development is sort + + align:start position:0% +cells going through development is sort + + + align:start position:0% +cells going through development is sort +of getting funneled into these distinct + + align:start position:0% +of getting funneled into these distinct + + + align:start position:0% +of getting funneled into these distinct +paths in in this case it's kind of + + align:start position:0% +paths in in this case it's kind of + + + align:start position:0% +paths in in this case it's kind of +random but in development it relies on + + align:start position:0% +random but in development it relies on + + + align:start position:0% +random but in development it relies on +signaling between cells and interaction + + align:start position:0% +signaling between cells and interaction + + + align:start position:0% +signaling between cells and interaction +between cells and the multicellular + + align:start position:0% +between cells and the multicellular + + + align:start position:0% +between cells and the multicellular +organism okay okay so as an example I + + align:start position:0% +organism okay okay so as an example I + + + align:start position:0% +organism okay okay so as an example I +want to tell you about early mammalian + + align:start position:0% +want to tell you about early mammalian + + + align:start position:0% +want to tell you about early mammalian +development in the differentiation of + + align:start position:0% +development in the differentiation of + + + align:start position:0% +development in the differentiation of +cell types in the early mammalian embryo + + align:start position:0% + + + + align:start position:0% + +okay so we start with an oocyte it's the + + align:start position:0% +okay so we start with an oocyte it's the + + + align:start position:0% +okay so we start with an oocyte it's the +female gamete and the male gamete the + + align:start position:0% +female gamete and the male gamete the + + + align:start position:0% +female gamete and the male gamete the +sperm so these can come together to form + + align:start position:0% +sperm so these can come together to form + + + align:start position:0% +sperm so these can come together to form +the zygote if I draw a little circle in + + align:start position:0% +the zygote if I draw a little circle in + + + align:start position:0% +the zygote if I draw a little circle in +the middle it's a nucleus okay in this + + align:start position:0% +the middle it's a nucleus okay in this + + + align:start position:0% +the middle it's a nucleus okay in this +is I goat is totipotent and the embryo + + align:start position:0% +is I goat is totipotent and the embryo + + + align:start position:0% +is I goat is totipotent and the embryo +undergoes cleavage divisions which I'll + + align:start position:0% +undergoes cleavage divisions which I'll + + + align:start position:0% +undergoes cleavage divisions which I'll +show here you see how that zygote + + align:start position:0% +show here you see how that zygote + + + align:start position:0% +show here you see how that zygote +divided into two cells now it's going to + + align:start position:0% +divided into two cells now it's going to + + + align:start position:0% +divided into two cells now it's going to +divide into four and it'll keep dividing + + align:start position:0% +divide into four and it'll keep dividing + + + align:start position:0% +divide into four and it'll keep dividing +until it's 16 probably so you get + + align:start position:0% +until it's 16 probably so you get + + + align:start position:0% +until it's 16 probably so you get +cleavage divisions that generate more + + align:start position:0% +cleavage divisions that generate more + + + align:start position:0% +cleavage divisions that generate more +than one cell you start with a single + + align:start position:0% +than one cell you start with a single + + + align:start position:0% +than one cell you start with a single +cell the cleavage divisions give you + + align:start position:0% +cell the cleavage divisions give you + + + align:start position:0% +cell the cleavage divisions give you +more than one cell and what you see up + + align:start position:0% +more than one cell and what you see up + + + align:start position:0% +more than one cell and what you see up +here now is a stage known as the blast + + align:start position:0% +here now is a stage known as the blast + + + align:start position:0% +here now is a stage known as the blast +of blastocyst or the blastula you can + + align:start position:0% +of blastocyst or the blastula you can + + + align:start position:0% +of blastocyst or the blastula you can +see there's a hollow sort of inner + + align:start position:0% +see there's a hollow sort of inner + + + align:start position:0% +see there's a hollow sort of inner +fluid-filled area here and you see their + + align:start position:0% +fluid-filled area here and you see their + + + align:start position:0% +fluid-filled area here and you see their +cells around + + align:start position:0% +cells around + + + align:start position:0% +cells around +that fluid-filled cavity and there's a + + align:start position:0% +that fluid-filled cavity and there's a + + + align:start position:0% +that fluid-filled cavity and there's a +thickening on one side of the embryo + + align:start position:0% +thickening on one side of the embryo + + + align:start position:0% +thickening on one side of the embryo +okay so I'm gonna draw that out here + + align:start position:0% + + + + align:start position:0% + +sorry mine is a little flat up here + + align:start position:0% +sorry mine is a little flat up here + + + align:start position:0% +sorry mine is a little flat up here +should be perfectly spherical okay and + + align:start position:0% +should be perfectly spherical okay and + + + align:start position:0% +should be perfectly spherical okay and +there there's this thickening on one + + align:start position:0% +there there's this thickening on one + + + align:start position:0% +there there's this thickening on one +side of the blastula which is a bunch of + + align:start position:0% +side of the blastula which is a bunch of + + + align:start position:0% +side of the blastula which is a bunch of +cells that are kind of interior and on + + align:start position:0% +cells that are kind of interior and on + + + align:start position:0% +cells that are kind of interior and on +the inside of the embryo + + align:start position:0% +the inside of the embryo + + + align:start position:0% +the inside of the embryo +okay these cells on the interior are + + align:start position:0% +okay these cells on the interior are + + + align:start position:0% +okay these cells on the interior are +known as the inner cell mass and these + + align:start position:0% +known as the inner cell mass and these + + + align:start position:0% +known as the inner cell mass and these +cells are now restricted in what they + + align:start position:0% +cells are now restricted in what they + + + align:start position:0% +cells are now restricted in what they +can become + + align:start position:0% +can become + + + align:start position:0% +can become +these cells will become the embryo + + align:start position:0% +these cells will become the embryo + + + align:start position:0% +these cells will become the embryo +proper okay so they'll become the cell + + align:start position:0% +proper okay so they'll become the cell + + + align:start position:0% +proper okay so they'll become the cell +types that'll be a part of the fetus + + align:start position:0% +types that'll be a part of the fetus + + + align:start position:0% +types that'll be a part of the fetus +this these cells on the outside are + + align:start position:0% +this these cells on the outside are + + + align:start position:0% +this these cells on the outside are +known as the trophoblast cells and these + + align:start position:0% +known as the trophoblast cells and these + + + align:start position:0% +known as the trophoblast cells and these +are these cells will form part of the + + align:start position:0% +are these cells will form part of the + + + align:start position:0% +are these cells will form part of the +placenta the embryonic portion of the + + align:start position:0% +placenta the embryonic portion of the + + + align:start position:0% +placenta the embryonic portion of the +placenta so they form part of the + + align:start position:0% +placenta so they form part of the + + + align:start position:0% +placenta so they form part of the +placenta and they're important for this + + align:start position:0% +placenta and they're important for this + + + align:start position:0% +placenta and they're important for this +embryo being able to implant into the + + align:start position:0% +embryo being able to implant into the + + + align:start position:0% +embryo being able to implant into the +uterine wall okay so if we think about + + align:start position:0% +uterine wall okay so if we think about + + + align:start position:0% +uterine wall okay so if we think about +this is the first example of + + align:start position:0% +this is the first example of + + + align:start position:0% +this is the first example of +differentiation in the early mammalian + + align:start position:0% +differentiation in the early mammalian + + + align:start position:0% +differentiation in the early mammalian +embryo B as you can see based on what I + + align:start position:0% +embryo B as you can see based on what I + + + align:start position:0% +embryo B as you can see based on what I +said here + + align:start position:0% +said here + + + align:start position:0% +said here +these cells are becoming restricted and + + align:start position:0% +these cells are becoming restricted and + + + align:start position:0% +these cells are becoming restricted and +what they can become okay so this is + + align:start position:0% +what they can become okay so this is + + + align:start position:0% +what they can become okay so this is +kind of like the first branch point in + + align:start position:0% +kind of like the first branch point in + + + align:start position:0% +kind of like the first branch point in +differentiation so we get some more sort + + align:start position:0% +differentiation so we get some more sort + + + align:start position:0% +differentiation so we get some more sort +of marbles going down here alright so + + align:start position:0% +of marbles going down here alright so + + + align:start position:0% +of marbles going down here alright so +this would be the sort of stage right + + align:start position:0% +this would be the sort of stage right + + + align:start position:0% +this would be the sort of stage right +before the blastula before + + align:start position:0% +before the blastula before + + + align:start position:0% +before the blastula before +differentiation and you can see these + + align:start position:0% +differentiation and you can see these + + + align:start position:0% +differentiation and you can see these +marbles when I let them they will have + + align:start position:0% +marbles when I let them they will have + + + align:start position:0% +marbles when I let them they will have +it they will either go this way and + + align:start position:0% +it they will either go this way and + + + align:start position:0% +it they will either go this way and +become one fate or they'll go the other + + align:start position:0% +become one fate or they'll go the other + + + align:start position:0% +become one fate or they'll go the other +way and be sort of direct + + align:start position:0% +way and be sort of direct + + + align:start position:0% +way and be sort of direct +down on another sort of potential fates + + align:start position:0% +down on another sort of potential fates + + + align:start position:0% +down on another sort of potential fates +yep + + align:start position:0% +yep + + + align:start position:0% +yep +there we go so this is the first sort of + + align:start position:0% +there we go so this is the first sort of + + + align:start position:0% +there we go so this is the first sort of +branch point if you will in fake + + align:start position:0% +branch point if you will in fake + + + align:start position:0% +branch point if you will in fake +determination for the mammalian embryo + + align:start position:0% +determination for the mammalian embryo + + + align:start position:0% +determination for the mammalian embryo +and so this branch point here right is + + align:start position:0% +and so this branch point here right is + + + align:start position:0% +and so this branch point here right is +different from this because once the + + align:start position:0% +different from this because once the + + + align:start position:0% +different from this because once the +marble goes one way or the other it's + + align:start position:0% +marble goes one way or the other it's + + + align:start position:0% +marble goes one way or the other it's +restricted in what fate it can become + + align:start position:0% +restricted in what fate it can become + + + align:start position:0% +restricted in what fate it can become +okay so this is the so this these cells + + align:start position:0% +okay so this is the so this these cells + + + align:start position:0% +okay so this is the so this these cells +here are not totipotent because they + + align:start position:0% +here are not totipotent because they + + + align:start position:0% +here are not totipotent because they +can't form the trophoblast they can't + + align:start position:0% +can't form the trophoblast they can't + + + align:start position:0% +can't form the trophoblast they can't +form the part of the placenta needed by + + align:start position:0% +form the part of the placenta needed by + + + align:start position:0% +form the part of the placenta needed by +the embryo but they do form the embryo + + align:start position:0% +the embryo but they do form the embryo + + + align:start position:0% +the embryo but they do form the embryo +proper so they are still capable of many + + align:start position:0% +proper so they are still capable of many + + + align:start position:0% +proper so they are still capable of many +faiths and so these cells are known as + + align:start position:0% +faiths and so these cells are known as + + + align:start position:0% +faiths and so these cells are known as +pluripotent which means capable of many + + align:start position:0% +pluripotent which means capable of many + + + align:start position:0% +pluripotent which means capable of many +things okay and so a type of cell type + + align:start position:0% +things okay and so a type of cell type + + + align:start position:0% +things okay and so a type of cell type +which I'm sure you've heard about is + + align:start position:0% +which I'm sure you've heard about is + + + align:start position:0% +which I'm sure you've heard about is +called embryonic stem cells or ES cells + + align:start position:0% + + + + align:start position:0% + +these ES cells are derived from the + + align:start position:0% +these ES cells are derived from the + + + align:start position:0% +these ES cells are derived from the +inner cell mass okay so these would be + + align:start position:0% +inner cell mass okay so these would be + + + align:start position:0% +inner cell mass okay so these would be +if they were taken out of the blastula + + align:start position:0% +if they were taken out of the blastula + + + align:start position:0% +if they were taken out of the blastula +sorry this is called the blastula if + + align:start position:0% +sorry this is called the blastula if + + + align:start position:0% +sorry this is called the blastula if +they're are taken from the blastula + + align:start position:0% +they're are taken from the blastula + + + align:start position:0% +they're are taken from the blastula +and cultured in vitro that these would + + align:start position:0% +and cultured in vitro that these would + + + align:start position:0% +and cultured in vitro that these would +be sort of embryonic stem cells that can + + align:start position:0% +be sort of embryonic stem cells that can + + + align:start position:0% +be sort of embryonic stem cells that can +be propagated okay so and they form the + + align:start position:0% +be propagated okay so and they form the + + + align:start position:0% +be propagated okay so and they form the +embryo proper right so these are + + align:start position:0% +embryo proper right so these are + + + align:start position:0% +embryo proper right so these are +pluripotent stem cells that can + + align:start position:0% +pluripotent stem cells that can + + + align:start position:0% +pluripotent stem cells that can +basically they are still capable of + + align:start position:0% +basically they are still capable of + + + align:start position:0% +basically they are still capable of +forming sort of any of the cell types in + + align:start position:0% +forming sort of any of the cell types in + + + align:start position:0% +forming sort of any of the cell types in +the embryo capable of forming + + align:start position:0% +the embryo capable of forming + + + align:start position:0% +the embryo capable of forming +embryonic cell types + + align:start position:0% + + + + align:start position:0% + +okay now let's look at the next slide so + + align:start position:0% +okay now let's look at the next slide so + + + align:start position:0% +okay now let's look at the next slide so +this this branch point right this first + + align:start position:0% +this this branch point right this first + + + align:start position:0% +this this branch point right this first +branch point sort of in development is + + align:start position:0% +branch point sort of in development is + + + align:start position:0% +branch point sort of in development is +associated with changes in gene + + align:start position:0% +associated with changes in gene + + + align:start position:0% +associated with changes in gene +expression okay so there are changes in + + align:start position:0% +expression okay so there are changes in + + + align:start position:0% +expression okay so there are changes in +gene expression and you're seeing one up + + align:start position:0% +gene expression and you're seeing one up + + + align:start position:0% +gene expression and you're seeing one up +on the slide above the slide above is a + + align:start position:0% +on the slide above the slide above is a + + + align:start position:0% +on the slide above the slide above is a +fixed blastula and all of the nuclei and + + align:start position:0% +fixed blastula and all of the nuclei and + + + align:start position:0% +fixed blastula and all of the nuclei and +the blastula are stained with green but + + align:start position:0% +the blastula are stained with green but + + + align:start position:0% +the blastula are stained with green but +there's one gene that's stained in red + + align:start position:0% +there's one gene that's stained in red + + + align:start position:0% +there's one gene that's stained in red +that's called act four and this is a + + align:start position:0% +that's called act four and this is a + + + align:start position:0% +that's called act four and this is a +transcription factor that marks sort of + + align:start position:0% +transcription factor that marks sort of + + + align:start position:0% +transcription factor that marks sort of +pluripotency and you can see how it's + + align:start position:0% +pluripotency and you can see how it's + + + align:start position:0% +pluripotency and you can see how it's +expressed specifically in these cells of + + align:start position:0% +expressed specifically in these cells of + + + align:start position:0% +expressed specifically in these cells of +the inner cell mass which are the what + + align:start position:0% +the inner cell mass which are the what + + + align:start position:0% +the inner cell mass which are the what +the embryonic stem cells are derived + + align:start position:0% +the embryonic stem cells are derived + + + align:start position:0% +the embryonic stem cells are derived +from okay so they're clearly changes in + + align:start position:0% +from okay so they're clearly changes in + + + align:start position:0% +from okay so they're clearly changes in +gene expression and one question you + + align:start position:0% +gene expression and one question you + + + align:start position:0% +gene expression and one question you +might have is whether or not these cells + + align:start position:0% +might have is whether or not these cells + + + align:start position:0% +might have is whether or not these cells +that that are going to form the embryo + + align:start position:0% +that that are going to form the embryo + + + align:start position:0% +that that are going to form the embryo +proper whether they have lost + + align:start position:0% +proper whether they have lost + + + align:start position:0% +proper whether they have lost +information such that they're unable to + + align:start position:0% +information such that they're unable to + + + align:start position:0% +information such that they're unable to +form the part of the placenta okay and + + align:start position:0% +form the part of the placenta okay and + + + align:start position:0% +form the part of the placenta okay and +you can also ask this for an adult cell + + align:start position:0% +you can also ask this for an adult cell + + + align:start position:0% +you can also ask this for an adult cell +right has an adult cell in your body + + align:start position:0% +right has an adult cell in your body + + + align:start position:0% +right has an adult cell in your body +hasn't lost gene content such that it's + + align:start position:0% +hasn't lost gene content such that it's + + + align:start position:0% +hasn't lost gene content such that it's +unable to make an entire organism okay + + align:start position:0% +unable to make an entire organism okay + + + align:start position:0% +unable to make an entire organism okay +I'm gonna tell you the answer I want you + + align:start position:0% +I'm gonna tell you the answer I want you + + + align:start position:0% +I'm gonna tell you the answer I want you +to think about what experiment would + + align:start position:0% +to think about what experiment would + + + align:start position:0% +to think about what experiment would +allow you to sort of determine the + + align:start position:0% +allow you to sort of determine the + + + align:start position:0% +allow you to sort of determine the +answer but I'm gonna tell you the answer + + align:start position:0% +answer but I'm gonna tell you the answer + + + align:start position:0% +answer but I'm gonna tell you the answer +is that there is not a loss of gene + + align:start position:0% +is that there is not a loss of gene + + + align:start position:0% +is that there is not a loss of gene +content but this differentiation process + + align:start position:0% +content but this differentiation process + + + align:start position:0% +content but this differentiation process +is due to changes in gene expression for + + align:start position:0% +is due to changes in gene expression for + + + align:start position:0% +is due to changes in gene expression for +the vast majority of our cell types okay + + align:start position:0% +the vast majority of our cell types okay + + + align:start position:0% +the vast majority of our cell types okay +so let's say you wanted to determine + + align:start position:0% +so let's say you wanted to determine + + + align:start position:0% +so let's say you wanted to determine +whether or not a differentiated cell had + + align:start position:0% +whether or not a differentiated cell had + + + align:start position:0% +whether or not a differentiated cell had +lost some sort of capability to + + align:start position:0% +lost some sort of capability to + + + align:start position:0% +lost some sort of capability to +regenerate an entire organism what might + + align:start position:0% +regenerate an entire organism what might + + + align:start position:0% +regenerate an entire organism what might +be some type of experiment you could do + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +to see it alright great so Brett had two + + align:start position:0% +to see it alright great so Brett had two + + + align:start position:0% +to see it alright great so Brett had two +really good points I think the first is + + align:start position:0% +really good points I think the first is + + + align:start position:0% +really good points I think the first is +to try to sort of reproduce conditions + + align:start position:0% +to try to sort of reproduce conditions + + + align:start position:0% +to try to sort of reproduce conditions +of pluripotency or you could even try to + + align:start position:0% +of pluripotency or you could even try to + + + align:start position:0% +of pluripotency or you could even try to +reproduce conditions of totipotency + + align:start position:0% +reproduce conditions of totipotency + + + align:start position:0% +reproduce conditions of totipotency +right in which case you'd want to sort + + align:start position:0% +right in which case you'd want to sort + + + align:start position:0% +right in which case you'd want to sort +of like take the genetic material of the + + align:start position:0% +of like take the genetic material of the + + + align:start position:0% +of like take the genetic material of the +somatic cell and sort of put it back in + + align:start position:0% +somatic cell and sort of put it back in + + + align:start position:0% +somatic cell and sort of put it back in +this situation where its present sort of + + align:start position:0% +this situation where its present sort of + + + align:start position:0% +this situation where its present sort of +in the cytoplasm of a zygote okay and + + align:start position:0% +in the cytoplasm of a zygote okay and + + + align:start position:0% +in the cytoplasm of a zygote okay and +the other point that Brett's made is to + + align:start position:0% +the other point that Brett's made is to + + + align:start position:0% +the other point that Brett's made is to +try to maybe like express something that + + align:start position:0% +try to maybe like express something that + + + align:start position:0% +try to maybe like express something that +would induce this type of pluripotent + + align:start position:0% +would induce this type of pluripotent + + + align:start position:0% +would induce this type of pluripotent +state if we knew exactly what the genes + + align:start position:0% +state if we knew exactly what the genes + + + align:start position:0% +state if we knew exactly what the genes +were that sort of like create this + + align:start position:0% +were that sort of like create this + + + align:start position:0% +were that sort of like create this +pluripotent state maybe we could just + + align:start position:0% +pluripotent state maybe we could just + + + align:start position:0% +pluripotent state maybe we could just +Express those genes and regenerate sort + + align:start position:0% +Express those genes and regenerate sort + + + align:start position:0% +Express those genes and regenerate sort +of a cell that sort of moves from like + + align:start position:0% +of a cell that sort of moves from like + + + align:start position:0% +of a cell that sort of moves from like +way down here all the way up to the top + + align:start position:0% +way down here all the way up to the top + + + align:start position:0% +way down here all the way up to the top +again okay and actually what Brett + + align:start position:0% +again okay and actually what Brett + + + align:start position:0% +again okay and actually what Brett +suggested were the two experiments that + + align:start position:0% +suggested were the two experiments that + + + align:start position:0% +suggested were the two experiments that +won these two folks the Nobel Prize in + + align:start position:0% +won these two folks the Nobel Prize in + + + align:start position:0% +won these two folks the Nobel Prize in +2012 so in 2012 the Nobel Prize was + + align:start position:0% +2012 so in 2012 the Nobel Prize was + + + align:start position:0% +2012 so in 2012 the Nobel Prize was +awarded jointly to Sir John Gurdon right + + align:start position:0% +awarded jointly to Sir John Gurdon right + + + align:start position:0% +awarded jointly to Sir John Gurdon right +here + + align:start position:0% +here + + + align:start position:0% +here +who incidentally has the best hair of + + align:start position:0% +who incidentally has the best hair of + + + align:start position:0% +who incidentally has the best hair of +all Nobel laureates and also Shinya + + align:start position:0% +all Nobel laureates and also Shinya + + + align:start position:0% +all Nobel laureates and also Shinya +Yamanaka okay and so these two folks + + align:start position:0% +Yamanaka okay and so these two folks + + + align:start position:0% +Yamanaka okay and so these two folks +were awarded the Nobel Prize for being + + align:start position:0% +were awarded the Nobel Prize for being + + + align:start position:0% +were awarded the Nobel Prize for being +able to show that mature differentiated + + align:start position:0% +able to show that mature differentiated + + + align:start position:0% +able to show that mature differentiated +cells can be reprogrammed to be to + + align:start position:0% +cells can be reprogrammed to be to + + + align:start position:0% +cells can be reprogrammed to be to +become pluripotent again okay which + + align:start position:0% +become pluripotent again okay which + + + align:start position:0% +become pluripotent again okay which +basically gives us the conclusion that + + align:start position:0% +basically gives us the conclusion that + + + align:start position:0% +basically gives us the conclusion that +there's not a loss of gene content + + align:start position:0% +there's not a loss of gene content + + + align:start position:0% +there's not a loss of gene content +during the differentiation process and + + align:start position:0% +during the differentiation process and + + + align:start position:0% +during the differentiation process and +the work from Yamanaka showed us + + align:start position:0% +the work from Yamanaka showed us + + + align:start position:0% +the work from Yamanaka showed us +of all genes whose expression is + + align:start position:0% +of all genes whose expression is + + + align:start position:0% +of all genes whose expression is +critical to induce this type of + + align:start position:0% +critical to induce this type of + + + align:start position:0% +critical to induce this type of +reprogramming okay and their work + + align:start position:0% +reprogramming okay and their work + + + align:start position:0% +reprogramming okay and their work +spanned from frogs so John Gurdon worked + + align:start position:0% +spanned from frogs so John Gurdon worked + + + align:start position:0% +spanned from frogs so John Gurdon worked +on development of frogs specifically + + align:start position:0% +on development of frogs specifically + + + align:start position:0% +on development of frogs specifically +xenakis Lavis which you've seen before + + align:start position:0% +xenakis Lavis which you've seen before + + + align:start position:0% +xenakis Lavis which you've seen before +Shinya Yamanaka is work involved mice + + align:start position:0% +Shinya Yamanaka is work involved mice + + + align:start position:0% +Shinya Yamanaka is work involved mice +and also human cell lines okay so I'm + + align:start position:0% +and also human cell lines okay so I'm + + + align:start position:0% +and also human cell lines okay so I'm +going to tell you about their + + align:start position:0% +going to tell you about their + + + align:start position:0% +going to tell you about their +experiments and how this sort of + + align:start position:0% +experiments and how this sort of + + + align:start position:0% +experiments and how this sort of +demonstrated this conclusion here and + + align:start position:0% +demonstrated this conclusion here and + + + align:start position:0% +demonstrated this conclusion here and +the first thing I want to show you is an + + align:start position:0% +the first thing I want to show you is an + + + align:start position:0% +the first thing I want to show you is an +experiment which is very simple + + align:start position:0% +experiment which is very simple + + + align:start position:0% +experiment which is very simple +conceptually technically it's very + + align:start position:0% +conceptually technically it's very + + + align:start position:0% +conceptually technically it's very +complicated which is if you are able to + + align:start position:0% +complicated which is if you are able to + + + align:start position:0% +complicated which is if you are able to +take a nucleus from an adult cell that's + + align:start position:0% +take a nucleus from an adult cell that's + + + align:start position:0% +take a nucleus from an adult cell that's +differentiated could you get it to + + align:start position:0% +differentiated could you get it to + + + align:start position:0% +differentiated could you get it to +change by introducing it back into the + + align:start position:0% +change by introducing it back into the + + + align:start position:0% +change by introducing it back into the +egg cell or a zygote cell okay so this + + align:start position:0% +egg cell or a zygote cell okay so this + + + align:start position:0% +egg cell or a zygote cell okay so this +experiment involves having an oocyte but + + align:start position:0% +experiment involves having an oocyte but + + + align:start position:0% +experiment involves having an oocyte but +in this case an oocyte where the nucleus + + align:start position:0% +in this case an oocyte where the nucleus + + + align:start position:0% +in this case an oocyte where the nucleus +has been removed okay so you're taking + + align:start position:0% +has been removed okay so you're taking + + + align:start position:0% +has been removed okay so you're taking +enucleated + + align:start position:0% +enucleated + + + align:start position:0% +enucleated +a site and you want to know if the + + align:start position:0% +a site and you want to know if the + + + align:start position:0% +a site and you want to know if the +cytoplasm of this Oh site is somehow + + align:start position:0% +cytoplasm of this Oh site is somehow + + + align:start position:0% +cytoplasm of this Oh site is somehow +special that would allow it to reprogram + + align:start position:0% +special that would allow it to reprogram + + + align:start position:0% +special that would allow it to reprogram +the nucleus of a differentiated cell and + + align:start position:0% +the nucleus of a differentiated cell and + + + align:start position:0% +the nucleus of a differentiated cell and +so you could suck up the nucleus of a + + align:start position:0% +so you could suck up the nucleus of a + + + align:start position:0% +so you could suck up the nucleus of a +differentiated cell so somatic cells + + align:start position:0% +differentiated cell so somatic cells + + + align:start position:0% +differentiated cell so somatic cells +another way to say differentiated the + + align:start position:0% +another way to say differentiated the + + + align:start position:0% +another way to say differentiated the +somatic cell nucleus and the experiment + + align:start position:0% +somatic cell nucleus and the experiment + + + align:start position:0% +somatic cell nucleus and the experiment +conceptually then is to just take this + + align:start position:0% +conceptually then is to just take this + + + align:start position:0% +conceptually then is to just take this +somatic cell nucleus that you've sucked + + align:start position:0% +somatic cell nucleus that you've sucked + + + align:start position:0% +somatic cell nucleus that you've sucked +up and inject it into an oocyte without + + align:start position:0% +up and inject it into an oocyte without + + + align:start position:0% +up and inject it into an oocyte without +a nucleus and see if the cytoplasm of + + align:start position:0% +a nucleus and see if the cytoplasm of + + + align:start position:0% +a nucleus and see if the cytoplasm of +this Oh site is somehow able to sort of + + align:start position:0% +this Oh site is somehow able to sort of + + + align:start position:0% +this Oh site is somehow able to sort of +change the properties of the nucleus + + align:start position:0% +change the properties of the nucleus + + + align:start position:0% +change the properties of the nucleus +such that it now is in an + + align:start position:0% +such that it now is in an + + + align:start position:0% +such that it now is in an +undifferentiated state so you generate a + + align:start position:0% +undifferentiated state so you generate a + + + align:start position:0% +undifferentiated state so you generate a +site now + + align:start position:0% + + + + align:start position:0% + +with the somatic cell nucleus and the + + align:start position:0% +with the somatic cell nucleus and the + + + align:start position:0% +with the somatic cell nucleus and the +question is whether this somatic cell + + align:start position:0% +question is whether this somatic cell + + + align:start position:0% +question is whether this somatic cell +nucleus is capable of generating the + + align:start position:0% +nucleus is capable of generating the + + + align:start position:0% +nucleus is capable of generating the +diversity of cell types that are + + align:start position:0% +diversity of cell types that are + + + align:start position:0% +diversity of cell types that are +normally present in an organism so you + + align:start position:0% +normally present in an organism so you + + + align:start position:0% +normally present in an organism so you +could then let this go and develop you + + align:start position:0% +could then let this go and develop you + + + align:start position:0% +could then let this go and develop you +can let it develop into a blast do + + align:start position:0% +can let it develop into a blast do + + + align:start position:0% +can let it develop into a blast do +blastula which I'm drawing here so you + + align:start position:0% +blastula which I'm drawing here so you + + + align:start position:0% +blastula which I'm drawing here so you +could generate a blastula and this will + + align:start position:0% +could generate a blastula and this will + + + align:start position:0% +could generate a blastula and this will +be a way to get embryonic stem cells + + align:start position:0% +be a way to get embryonic stem cells + + + align:start position:0% +be a way to get embryonic stem cells +derived from sort of this type of + + align:start position:0% +derived from sort of this type of + + + align:start position:0% +derived from sort of this type of +nucleus but you can also let it grow + + align:start position:0% +nucleus but you can also let it grow + + + align:start position:0% +nucleus but you can also let it grow +into an entire organism but this + + align:start position:0% +into an entire organism but this + + + align:start position:0% +into an entire organism but this +organism would be genetically identical + + align:start position:0% +organism would be genetically identical + + + align:start position:0% +organism would be genetically identical +to whatever organism donated this + + align:start position:0% +to whatever organism donated this + + + align:start position:0% +to whatever organism donated this +nucleus okay so because you're + + align:start position:0% +nucleus okay so because you're + + + align:start position:0% +nucleus okay so because you're +duplicating an organism that is known as + + align:start position:0% +duplicating an organism that is known as + + + align:start position:0% +duplicating an organism that is known as +reproductive cloning + + align:start position:0% +reproductive cloning + + + align:start position:0% +reproductive cloning +this is reproductive cloning if you go + + align:start position:0% +this is reproductive cloning if you go + + + align:start position:0% +this is reproductive cloning if you go +all the way to the organism I'll show + + align:start position:0% +all the way to the organism I'll show + + + align:start position:0% +all the way to the organism I'll show +you just a little video on the nuclear + + align:start position:0% +you just a little video on the nuclear + + + align:start position:0% +you just a little video on the nuclear +transfer you see now that this drilling + + align:start position:0% +transfer you see now that this drilling + + + align:start position:0% +transfer you see now that this drilling +pipette is going to suck it drill a + + align:start position:0% +pipette is going to suck it drill a + + + align:start position:0% +pipette is going to suck it drill a +little hole into the membrane you can + + align:start position:0% +little hole into the membrane you can + + + align:start position:0% +little hole into the membrane you can +maybe see a little bit of the hole right + + align:start position:0% +maybe see a little bit of the hole right + + + align:start position:0% +maybe see a little bit of the hole right +here at the next part it's talking about + + align:start position:0% +here at the next part it's talking about + + + align:start position:0% +here at the next part it's talking about +this pipette here you can see a bit of + + align:start position:0% +this pipette here you can see a bit of + + + align:start position:0% +this pipette here you can see a bit of +the hole and now the pipette is gonna go + + align:start position:0% +the hole and now the pipette is gonna go + + + align:start position:0% +the hole and now the pipette is gonna go +in and remove the nucleus and if you + + align:start position:0% +in and remove the nucleus and if you + + + align:start position:0% +in and remove the nucleus and if you +look carefully in the pipette you'll see + + align:start position:0% +look carefully in the pipette you'll see + + + align:start position:0% +look carefully in the pipette you'll see +a line in the nucleus which are all the + + align:start position:0% +a line in the nucleus which are all the + + + align:start position:0% +a line in the nucleus which are all the +chromosomes lined up so their nucleus is + + align:start position:0% +chromosomes lined up so their nucleus is + + + align:start position:0% +chromosomes lined up so their nucleus is +going to be squirted out now because we + + align:start position:0% +going to be squirted out now because we + + + align:start position:0% +going to be squirted out now because we +don't need it anymore + + align:start position:0% +don't need it anymore + + + align:start position:0% +don't need it anymore +and there we have an enucleated egg now + + align:start position:0% +and there we have an enucleated egg now + + + align:start position:0% +and there we have an enucleated egg now +the next step is to take a set of eggs + + align:start position:0% +the next step is to take a set of eggs + + + align:start position:0% +the next step is to take a set of eggs +like that and I'll show you - and then + + align:start position:0% +like that and I'll show you - and then + + + align:start position:0% +like that and I'll show you - and then +transfer into them and nucleus from + + align:start position:0% +transfer into them and nucleus from + + + align:start position:0% +transfer into them and nucleus from +another kind of cell a fully + + align:start position:0% +another kind of cell a fully + + + align:start position:0% +another kind of cell a fully +differentiated cymatics + + align:start position:0% +differentiated cymatics + + + align:start position:0% +differentiated cymatics +so here the enucleated egg is set on the + + align:start position:0% +so here the enucleated egg is set on the + + + align:start position:0% +so here the enucleated egg is set on the +side then it's held by this holding + + align:start position:0% +side then it's held by this holding + + + align:start position:0% +side then it's held by this holding +pipette on the Left there's drilling the + + align:start position:0% +pipette on the Left there's drilling the + + + align:start position:0% +pipette on the Left there's drilling the +little hole in the membrane here we go + + align:start position:0% +little hole in the membrane here we go + + + align:start position:0% +little hole in the membrane here we go +in here comes the nucleus from the rice + + align:start position:0% +in here comes the nucleus from the rice + + + align:start position:0% +in here comes the nucleus from the rice +these pipettes are operated with a piezo + + align:start position:0% +these pipettes are operated with a piezo + + + align:start position:0% +these pipettes are operated with a piezo +electric device so you can't see it here + + align:start position:0% +electric device so you can't see it here + + + align:start position:0% +electric device so you can't see it here +but it's like a little jackhammer going + + align:start position:0% +but it's like a little jackhammer going + + + align:start position:0% +but it's like a little jackhammer going +very quickly like woody the woodpecker + + align:start position:0% +very quickly like woody the woodpecker + + + align:start position:0% +very quickly like woody the woodpecker +getting in there - I don't know if I + + align:start position:0% +getting in there - I don't know if I + + + align:start position:0% +getting in there - I don't know if I +would have used woody the woodpecker as + + align:start position:0% +would have used woody the woodpecker as + + + align:start position:0% +would have used woody the woodpecker as +an analogy but that's basically the idea + + align:start position:0% +an analogy but that's basically the idea + + + align:start position:0% +an analogy but that's basically the idea +okay so you can take a nucleus from a + + align:start position:0% +okay so you can take a nucleus from a + + + align:start position:0% +okay so you can take a nucleus from a +somatic cell and Transplant it if you + + align:start position:0% +somatic cell and Transplant it if you + + + align:start position:0% +somatic cell and Transplant it if you +will into an oocyte and then determine + + align:start position:0% +will into an oocyte and then determine + + + align:start position:0% +will into an oocyte and then determine +whether you can get either a blastula or + + align:start position:0% +whether you can get either a blastula or + + + align:start position:0% +whether you can get either a blastula or +an entire organism from that + + align:start position:0% +an entire organism from that + + + align:start position:0% +an entire organism from that +differentiated cells nucleus so this is + + align:start position:0% +differentiated cells nucleus so this is + + + align:start position:0% +differentiated cells nucleus so this is +one result from Sir John Gurdon and what + + align:start position:0% +one result from Sir John Gurdon and what + + + align:start position:0% +one result from Sir John Gurdon and what +the experiment was in this case was to + + align:start position:0% +the experiment was in this case was to + + + align:start position:0% +the experiment was in this case was to +take a sites or eggs from this wild-type + + align:start position:0% +take a sites or eggs from this wild-type + + + align:start position:0% +take a sites or eggs from this wild-type +lavis frog and a transplant nuclei from + + align:start position:0% +lavis frog and a transplant nuclei from + + + align:start position:0% +lavis frog and a transplant nuclei from +donor frogs that are ID by albino so you + + align:start position:0% +donor frogs that are ID by albino so you + + + align:start position:0% +donor frogs that are ID by albino so you +can see this is an elegant experiment in + + align:start position:0% +can see this is an elegant experiment in + + + align:start position:0% +can see this is an elegant experiment in +that you can sort of track the origin of + + align:start position:0% +that you can sort of track the origin of + + + align:start position:0% +that you can sort of track the origin of +the nucleus because it's genetically + + align:start position:0% +the nucleus because it's genetically + + + align:start position:0% +the nucleus because it's genetically +marked with this albino sort of + + align:start position:0% +marked with this albino sort of + + + align:start position:0% +marked with this albino sort of +phenotype so that you're getting a + + align:start position:0% +phenotype so that you're getting a + + + align:start position:0% +phenotype so that you're getting a +nuclei from you're getting some nuclei + + align:start position:0% +nuclei from you're getting some nuclei + + + align:start position:0% +nuclei from you're getting some nuclei +from albino tadpoles so these are + + align:start position:0% +from albino tadpoles so these are + + + align:start position:0% +from albino tadpoles so these are +differentiated cell nuclei and they're + + align:start position:0% +differentiated cell nuclei and they're + + + align:start position:0% +differentiated cell nuclei and they're +transplanted into wild-type donor eggs + + align:start position:0% +transplanted into wild-type donor eggs + + + align:start position:0% +transplanted into wild-type donor eggs +right so normally the wild-type frog + + align:start position:0% +right so normally the wild-type frog + + + align:start position:0% +right so normally the wild-type frog +would reproduce frogs that look like it + + align:start position:0% +would reproduce frogs that look like it + + + align:start position:0% +would reproduce frogs that look like it +that are non albino but in this + + align:start position:0% +that are non albino but in this + + + align:start position:0% +that are non albino but in this +experiment our Gurdon and his lab were + + align:start position:0% +experiment our Gurdon and his lab were + + + align:start position:0% +experiment our Gurdon and his lab were +able to get frogs that were albino okay + + align:start position:0% +able to get frogs that were albino okay + + + align:start position:0% +able to get frogs that were albino okay +so these would be sort of clones of + + align:start position:0% +so these would be sort of clones of + + + align:start position:0% +so these would be sort of clones of +whatever albino tadpoles they got the + + align:start position:0% +whatever albino tadpoles they got the + + + align:start position:0% +whatever albino tadpoles they got the +nuclei from okay so you see in this case + + align:start position:0% +nuclei from okay so you see in this case + + + align:start position:0% +nuclei from okay so you see in this case +it's the origin + + align:start position:0% +it's the origin + + + align:start position:0% +it's the origin +the nucleus that is determining sort of + + align:start position:0% +the nucleus that is determining sort of + + + align:start position:0% +the nucleus that is determining sort of +the the phenotype of these frogs so that + + align:start position:0% +the the phenotype of these frogs so that + + + align:start position:0% +the the phenotype of these frogs so that +allowed them to show that the nucleus is + + align:start position:0% +allowed them to show that the nucleus is + + + align:start position:0% +allowed them to show that the nucleus is +getting reprogrammed from this albino + + align:start position:0% +getting reprogrammed from this albino + + + align:start position:0% +getting reprogrammed from this albino +tadpole and is able to still generate + + align:start position:0% +tadpole and is able to still generate + + + align:start position:0% +tadpole and is able to still generate +all of the cell types present in a + + align:start position:0% +all of the cell types present in a + + + align:start position:0% +all of the cell types present in a +normal organism yes Brett yes yeah yeah + + align:start position:0% +normal organism yes Brett yes yeah yeah + + + align:start position:0% +normal organism yes Brett yes yeah yeah +so yeah and actually it was taking + + align:start position:0% +so yeah and actually it was taking + + + align:start position:0% +so yeah and actually it was taking +unfertilized eggs which is the biggest + + align:start position:0% +unfertilized eggs which is the biggest + + + align:start position:0% +unfertilized eggs which is the biggest +trick i think people had tried to do + + align:start position:0% +trick i think people had tried to do + + + align:start position:0% +trick i think people had tried to do +this in frogs before and it failed + + align:start position:0% +this in frogs before and it failed + + + align:start position:0% +this in frogs before and it failed +because they were using fertilized eggs + + align:start position:0% +because they were using fertilized eggs + + + align:start position:0% +because they were using fertilized eggs +and there's something about sort of the + + align:start position:0% +and there's something about sort of the + + + align:start position:0% +and there's something about sort of the +the state the oocyte development that + + align:start position:0% +the state the oocyte development that + + + align:start position:0% +the state the oocyte development that +makes it better at reprogramming the + + align:start position:0% +makes it better at reprogramming the + + + align:start position:0% +makes it better at reprogramming the +nucleus okay so that's with frogs so + + align:start position:0% +nucleus okay so that's with frogs so + + + align:start position:0% +nucleus okay so that's with frogs so +that that experiment was actually done + + align:start position:0% +that that experiment was actually done + + + align:start position:0% +that that experiment was actually done +in the late nineteen fifties published + + align:start position:0% +in the late nineteen fifties published + + + align:start position:0% +in the late nineteen fifties published +in the early 1960s and so it took + + align:start position:0% +in the early 1960s and so it took + + + align:start position:0% +in the early 1960s and so it took +another forty years or so for the first + + align:start position:0% +another forty years or so for the first + + + align:start position:0% +another forty years or so for the first +mammal to be cloned and you guys + + align:start position:0% +mammal to be cloned and you guys + + + align:start position:0% +mammal to be cloned and you guys +probably weren't even born yet but for + + align:start position:0% +probably weren't even born yet but for + + + align:start position:0% +probably weren't even born yet but for +those of us who are older we remember + + align:start position:0% +those of us who are older we remember + + + align:start position:0% +those of us who are older we remember +this because there was a big brouhaha + + align:start position:0% +this because there was a big brouhaha + + + align:start position:0% +this because there was a big brouhaha +over Dolly the sheep which was the first + + align:start position:0% +over Dolly the sheep which was the first + + + align:start position:0% +over Dolly the sheep which was the first +cloned mammal + + align:start position:0% +cloned mammal + + + align:start position:0% +cloned mammal +I believe that's Dolly there so this is + + align:start position:0% +I believe that's Dolly there so this is + + + align:start position:0% +I believe that's Dolly there so this is +I'm not sure which one is Dolly that + + align:start position:0% +I'm not sure which one is Dolly that + + + align:start position:0% +I'm not sure which one is Dolly that +they're both the same type of sheep so + + align:start position:0% +they're both the same type of sheep so + + + align:start position:0% +they're both the same type of sheep so +this was done by ian wilmut and his + + align:start position:0% +this was done by ian wilmut and his + + + align:start position:0% +this was done by ian wilmut and his +group one thing i want to point out + + align:start position:0% +group one thing i want to point out + + + align:start position:0% +group one thing i want to point out +about this is it's incredibly + + align:start position:0% +about this is it's incredibly + + + align:start position:0% +about this is it's incredibly +inefficient okay if you look over here + + align:start position:0% +inefficient okay if you look over here + + + align:start position:0% +inefficient okay if you look over here +right this dolly resulted from for over + + align:start position:0% +right this dolly resulted from for over + + + align:start position:0% +right this dolly resulted from for over +400 sites having this sort of nuclear + + align:start position:0% +400 sites having this sort of nuclear + + + align:start position:0% +400 sites having this sort of nuclear +transplant take place okay so it's not a + + align:start position:0% +transplant take place okay so it's not a + + + align:start position:0% +transplant take place okay so it's not a +very efficient process and so that lack + + align:start position:0% +very efficient process and so that lack + + + align:start position:0% +very efficient process and so that lack +of efficiency is due to the fact that + + align:start position:0% +of efficiency is due to the fact that + + + align:start position:0% +of efficiency is due to the fact that +the nucleus is resisting getting + + align:start position:0% +the nucleus is resisting getting + + + align:start position:0% +the nucleus is resisting getting +reprogrammed okay + + align:start position:0% +reprogrammed okay + + + align:start position:0% +reprogrammed okay +this is a graph from one of John Gurdon + + align:start position:0% +this is a graph from one of John Gurdon + + + align:start position:0% +this is a graph from one of John Gurdon +z' sort of he wrote a review article on + + align:start position:0% +z' sort of he wrote a review article on + + + align:start position:0% +z' sort of he wrote a review article on +sort of reprogramming after he won the + + align:start position:0% +sort of reprogramming after he won the + + + align:start position:0% +sort of reprogramming after he won the +Nobel Prize this is from that and what's + + align:start position:0% +Nobel Prize this is from that and what's + + + align:start position:0% +Nobel Prize this is from that and what's +plotted is sort of the the frequency in + + align:start position:0% +plotted is sort of the the frequency in + + + align:start position:0% +plotted is sort of the the frequency in +which transfers results in sort of a + + align:start position:0% +which transfers results in sort of a + + + align:start position:0% +which transfers results in sort of a +differentiated organism and what's on + + align:start position:0% +differentiated organism and what's on + + + align:start position:0% +differentiated organism and what's on +the x-axis is the stage of the cell + + align:start position:0% +the x-axis is the stage of the cell + + + align:start position:0% +the x-axis is the stage of the cell +that's used to transplant okay and so + + align:start position:0% +that's used to transplant okay and so + + + align:start position:0% +that's used to transplant okay and so +what you see is that over the course of + + align:start position:0% +what you see is that over the course of + + + align:start position:0% +what you see is that over the course of +differentiation it gets harder and + + align:start position:0% +differentiation it gets harder and + + + align:start position:0% +differentiation it gets harder and +harder for the nucleus to get + + align:start position:0% +harder for the nucleus to get + + + align:start position:0% +harder for the nucleus to get +reprogrammed to create a sort of all the + + align:start position:0% +reprogrammed to create a sort of all the + + + align:start position:0% +reprogrammed to create a sort of all the +cell types that are normally present in + + align:start position:0% +cell types that are normally present in + + + align:start position:0% +cell types that are normally present in +an adult animal + + align:start position:0% +an adult animal + + + align:start position:0% +an adult animal +okay so nuclei do become more restricted + + align:start position:0% +okay so nuclei do become more restricted + + + align:start position:0% +okay so nuclei do become more restricted +in their ability to be reprogrammed over + + align:start position:0% +in their ability to be reprogrammed over + + + align:start position:0% +in their ability to be reprogrammed over +development but the fact that any of + + align:start position:0% +development but the fact that any of + + + align:start position:0% +development but the fact that any of +them are able to be reprogrammed + + align:start position:0% +them are able to be reprogrammed + + + align:start position:0% +them are able to be reprogrammed +suggests that when they're we that + + align:start position:0% +suggests that when they're we that + + + align:start position:0% +suggests that when they're we that +during differentiation there's not a + + align:start position:0% +during differentiation there's not a + + + align:start position:0% +during differentiation there's not a +loss of gene content okay and John + + align:start position:0% +loss of gene content okay and John + + + align:start position:0% +loss of gene content okay and John +Gurdon has done a lot to characterize + + align:start position:0% +Gurdon has done a lot to characterize + + + align:start position:0% +Gurdon has done a lot to characterize +sort of the changes in the nucleus that + + align:start position:0% +sort of the changes in the nucleus that + + + align:start position:0% +sort of the changes in the nucleus that +happened during differentiation which + + align:start position:0% +happened during differentiation which + + + align:start position:0% +happened during differentiation which +sort of resist this reprogramming by the + + align:start position:0% +sort of resist this reprogramming by the + + + align:start position:0% +sort of resist this reprogramming by the +no site cytoplasm + + align:start position:0% + + + + align:start position:0% + +alright so mechanistically what's + + align:start position:0% +alright so mechanistically what's + + + align:start position:0% +alright so mechanistically what's +happening well one big one of the people + + align:start position:0% +happening well one big one of the people + + + align:start position:0% +happening well one big one of the people +who really showed what's going on there + + align:start position:0% +who really showed what's going on there + + + align:start position:0% +who really showed what's going on there +is Shinya Yamanaka and what his work + + align:start position:0% +is Shinya Yamanaka and what his work + + + align:start position:0% +is Shinya Yamanaka and what his work +shows is that you can take just a few + + align:start position:0% +shows is that you can take just a few + + + align:start position:0% +shows is that you can take just a few +genes it turns out is four and you can + + align:start position:0% +genes it turns out is four and you can + + + align:start position:0% +genes it turns out is four and you can +induce reprogramming by just expressing + + align:start position:0% +induce reprogramming by just expressing + + + align:start position:0% +induce reprogramming by just expressing +these four genes in an adult + + align:start position:0% +these four genes in an adult + + + align:start position:0% +these four genes in an adult +differentiated cell okay so in this case + + align:start position:0% + + + + align:start position:0% + +in this case you have a differentiated + + align:start position:0% +in this case you have a differentiated + + + align:start position:0% +in this case you have a differentiated +cell and what T initially used were + + align:start position:0% +cell and what T initially used were + + + align:start position:0% +cell and what T initially used were +fibroblasts which are a type of + + align:start position:0% +fibroblasts which are a type of + + + align:start position:0% +fibroblasts which are a type of +differentiated cell and what Yamanaka + + align:start position:0% +differentiated cell and what Yamanaka + + + align:start position:0% +differentiated cell and what Yamanaka +showed is that you can express four + + align:start position:0% +showed is that you can express four + + + align:start position:0% +showed is that you can express four +transcription factors one of them being + + align:start position:0% +transcription factors one of them being + + + align:start position:0% +transcription factors one of them being +this factor here acht 4 which is + + align:start position:0% +this factor here acht 4 which is + + + align:start position:0% +this factor here acht 4 which is +expressed in the inner cell mass and was + + align:start position:0% +expressed in the inner cell mass and was + + + align:start position:0% +expressed in the inner cell mass and was +shown to be involved involved in sort of + + align:start position:0% +shown to be involved involved in sort of + + + align:start position:0% +shown to be involved involved in sort of +maintaining pluripotency of these inner + + align:start position:0% +maintaining pluripotency of these inner + + + align:start position:0% +maintaining pluripotency of these inner +mass inner cell mass cells so you could + + align:start position:0% +mass inner cell mass cells so you could + + + align:start position:0% +mass inner cell mass cells so you could +take out 4 plus another transcription + + align:start position:0% +take out 4 plus another transcription + + + align:start position:0% +take out 4 plus another transcription +factor which is important for + + align:start position:0% +factor which is important for + + + align:start position:0% +factor which is important for +pluripotency plus 2 others and scénic + + align:start position:0% +pluripotency plus 2 others and scénic + + + align:start position:0% +pluripotency plus 2 others and scénic +these are the 4 so these are all + + align:start position:0% +these are the 4 so these are all + + + align:start position:0% +these are the 4 so these are all +transcription factors and what they + + align:start position:0% +transcription factors and what they + + + align:start position:0% +transcription factors and what they +found is if you express these four + + align:start position:0% +found is if you express these four + + + align:start position:0% +found is if you express these four +transcription factors in a + + align:start position:0% +transcription factors in a + + + align:start position:0% +transcription factors in a +differentiated cell you could get it + + align:start position:0% +differentiated cell you could get it + + + align:start position:0% +differentiated cell you could get it +revert to revert to a more pluripotent + + align:start position:0% +revert to revert to a more pluripotent + + + align:start position:0% +revert to revert to a more pluripotent +state ok so this results in what is + + align:start position:0% +state ok so this results in what is + + + align:start position:0% +state ok so this results in what is +known as induced pluripotent stem cells + + align:start position:0% +known as induced pluripotent stem cells + + + align:start position:0% +known as induced pluripotent stem cells +or iPS cells for short okay and then + + align:start position:0% +or iPS cells for short okay and then + + + align:start position:0% +or iPS cells for short okay and then +like embryonic stem cells all right here + + align:start position:0% +like embryonic stem cells all right here + + + align:start position:0% +like embryonic stem cells all right here +these cells can give rise to different + + align:start position:0% +these cells can give rise to different + + + align:start position:0% +these cells can give rise to different +cell types okay and so one of the goals + + align:start position:0% +cell types okay and so one of the goals + + + align:start position:0% +cell types okay and so one of the goals +of this field of developmental biology + + align:start position:0% +of this field of developmental biology + + + align:start position:0% +of this field of developmental biology +and and cell reprogramming is to use + + align:start position:0% +and and cell reprogramming is to use + + + align:start position:0% +and and cell reprogramming is to use +this technology to replace cells that + + align:start position:0% +this technology to replace cells that + + + align:start position:0% +this technology to replace cells that +are lost in patients so this is known as + + align:start position:0% +are lost in patients so this is known as + + + align:start position:0% +are lost in patients so this is known as +regenerative medicine + + align:start position:0% + + + + align:start position:0% + +and the idea of regenerator the theory + + align:start position:0% +and the idea of regenerator the theory + + + align:start position:0% +and the idea of regenerator the theory +of regenerative medicine is to take ES + + align:start position:0% +of regenerative medicine is to take ES + + + align:start position:0% +of regenerative medicine is to take ES +cells or induced pluripotent stem cells + + align:start position:0% + + + + align:start position:0% + +from patients and to be able to culture + + align:start position:0% +from patients and to be able to culture + + + align:start position:0% +from patients and to be able to culture +them in vitro so culture in vitro and + + align:start position:0% +them in vitro so culture in vitro and + + + align:start position:0% +them in vitro so culture in vitro and +then to be able to direct these cultured + + align:start position:0% +then to be able to direct these cultured + + + align:start position:0% +then to be able to direct these cultured +cells into different cell fates in order + + align:start position:0% +cells into different cell fates in order + + + align:start position:0% +cells into different cell fates in order +to use these cells possibly to + + align:start position:0% +to use these cells possibly to + + + align:start position:0% +to use these cells possibly to +transplant them back into an individual + + align:start position:0% +transplant them back into an individual + + + align:start position:0% +transplant them back into an individual +where maybe these cell types are dying + + align:start position:0% +where maybe these cell types are dying + + + align:start position:0% +where maybe these cell types are dying +okay so you could then differentiate + + align:start position:0% +okay so you could then differentiate + + + align:start position:0% +okay so you could then differentiate +these cells using certain biochemical + + align:start position:0% +these cells using certain biochemical + + + align:start position:0% +these cells using certain biochemical +signals that you can add to the media in + + align:start position:0% +signals that you can add to the media in + + + align:start position:0% +signals that you can add to the media in +order to create different cell types + + align:start position:0% +order to create different cell types + + + align:start position:0% +order to create different cell types +like neurons muscle babies skin okay one + + align:start position:0% +like neurons muscle babies skin okay one + + + align:start position:0% +like neurons muscle babies skin okay one +example of this was shown by Shinya + + align:start position:0% +example of this was shown by Shinya + + + align:start position:0% +example of this was shown by Shinya +Yamanaka where what they did was to take + + align:start position:0% +Yamanaka where what they did was to take + + + align:start position:0% +Yamanaka where what they did was to take +human human fibroblast cells put them + + align:start position:0% +human human fibroblast cells put them + + + align:start position:0% +human human fibroblast cells put them +back in the pluripotent state by + + align:start position:0% +back in the pluripotent state by + + + align:start position:0% +back in the pluripotent state by +expressing those four factors and then + + align:start position:0% +expressing those four factors and then + + + align:start position:0% +expressing those four factors and then +get these cells to differentiate into + + align:start position:0% +get these cells to differentiate into + + + align:start position:0% +get these cells to differentiate into +cardio cardiac tissue so cardiac cells + + align:start position:0% +cardio cardiac tissue so cardiac cells + + + align:start position:0% +cardio cardiac tissue so cardiac cells +here's a movie so these are from from + + align:start position:0% +here's a movie so these are from from + + + align:start position:0% +here's a movie so these are from from +adult fibroblast cells but now you can + + align:start position:0% +adult fibroblast cells but now you can + + + align:start position:0% +adult fibroblast cells but now you can +see they're beating like sort of like a + + align:start position:0% +see they're beating like sort of like a + + + align:start position:0% +see they're beating like sort of like a +cardiac tissue would okay so these were + + align:start position:0% +cardiac tissue would okay so these were + + + align:start position:0% +cardiac tissue would okay so these were +made into IPS stem cells cultured in + + align:start position:0% +made into IPS stem cells cultured in + + + align:start position:0% +made into IPS stem cells cultured in +vitro and then directed into a cardiac + + align:start position:0% +vitro and then directed into a cardiac + + + align:start position:0% +vitro and then directed into a cardiac +muscle fate okay so the goal would then + + align:start position:0% +muscle fate okay so the goal would then + + + align:start position:0% +muscle fate okay so the goal would then +to be used these + + align:start position:0% +to be used these + + + align:start position:0% +to be used these +and to transplant them back into back + + align:start position:0% +and to transplant them back into back + + + align:start position:0% +and to transplant them back into back +into a patient such that if a patient + + align:start position:0% +into a patient such that if a patient + + + align:start position:0% +into a patient such that if a patient +had let's say a neurodegenerative + + align:start position:0% +had let's say a neurodegenerative + + + align:start position:0% +had let's say a neurodegenerative +disease and was lacking a certain type + + align:start position:0% +disease and was lacking a certain type + + + align:start position:0% +disease and was lacking a certain type +of neuron you could then take cells + + align:start position:0% +of neuron you could then take cells + + + align:start position:0% +of neuron you could then take cells +start them on the path to neuronal + + align:start position:0% +start them on the path to neuronal + + + align:start position:0% +start them on the path to neuronal +development and then Transplant them + + align:start position:0% +development and then Transplant them + + + align:start position:0% +development and then Transplant them +back into that patient and if these + + align:start position:0% +back into that patient and if these + + + align:start position:0% +back into that patient and if these +cells are derived from the DNA of that + + align:start position:0% +cells are derived from the DNA of that + + + align:start position:0% +cells are derived from the DNA of that +patient then there won't be transplant + + align:start position:0% +patient then there won't be transplant + + + align:start position:0% +patient then there won't be transplant +rejection because what regulates + + align:start position:0% +rejection because what regulates + + + align:start position:0% +rejection because what regulates +transplant rejection is the major + + align:start position:0% +transplant rejection is the major + + + align:start position:0% +transplant rejection is the major +histocompatibility a complex locus and + + align:start position:0% +histocompatibility a complex locus and + + + align:start position:0% +histocompatibility a complex locus and +it's polymorphic but if you're taking a + + align:start position:0% +it's polymorphic but if you're taking a + + + align:start position:0% +it's polymorphic but if you're taking a +nucleus from the patient and then + + align:start position:0% +nucleus from the patient and then + + + align:start position:0% +nucleus from the patient and then +causing the cells to differentiate in + + align:start position:0% +causing the cells to differentiate in + + + align:start position:0% +causing the cells to differentiate in +vitro you're taking the exact same + + align:start position:0% +vitro you're taking the exact same + + + align:start position:0% +vitro you're taking the exact same +you're taking clonal cells and putting + + align:start position:0% +you're taking clonal cells and putting + + + align:start position:0% +you're taking clonal cells and putting +them back in the same patient such that + + align:start position:0% +them back in the same patient such that + + + align:start position:0% +them back in the same patient such that +they won't be rejected + + align:start position:0% +they won't be rejected + + + align:start position:0% +they won't be rejected +ideally all right now we want to try + + align:start position:0% +ideally all right now we want to try + + + align:start position:0% +ideally all right now we want to try +something with the remainder of our time + + align:start position:0% +something with the remainder of our time + + + align:start position:0% +something with the remainder of our time +I want a group all right everyone on + + align:start position:0% +I want a group all right everyone on + + + align:start position:0% +I want a group all right everyone on +this side of the room over I want you + + align:start position:0% +this side of the room over I want you + + + align:start position:0% +this side of the room over I want you +over here and everyone on this side of + + align:start position:0% +over here and everyone on this side of + + + align:start position:0% +over here and everyone on this side of +the room I want you on this side over + + align:start position:0% +the room I want you on this side over + + + align:start position:0% +the room I want you on this side over +here okay + + align:start position:0% +here okay + + + align:start position:0% +here okay +maybe maybe you guys could go over here + + align:start position:0% +maybe maybe you guys could go over here + + + align:start position:0% +maybe maybe you guys could go over here +so that we're more balanced we're gonna + + align:start position:0% +so that we're more balanced we're gonna + + + align:start position:0% +so that we're more balanced we're gonna +have a little debate + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% + + + + align:start position:0% + +you can sit down it's okay be in a + + align:start position:0% +you can sit down it's okay be in a + + + align:start position:0% +you can sit down it's okay be in a +position to talk to each other I want + + align:start position:0% +position to talk to each other I want + + + align:start position:0% +position to talk to each other I want +you guys talking to each other that's + + align:start position:0% +you guys talking to each other that's + + + align:start position:0% +you guys talking to each other that's +that's that was the goal of putting you + + align:start position:0% +that's that was the goal of putting you + + + align:start position:0% +that's that was the goal of putting you +close together okay okay so in the past + + align:start position:0% +close together okay okay so in the past + + + align:start position:0% +close together okay okay so in the past +couple weeks there has been a little bit + + align:start position:0% +couple weeks there has been a little bit + + + align:start position:0% +couple weeks there has been a little bit +of a stir because researcher there's a + + align:start position:0% +of a stir because researcher there's a + + + align:start position:0% +of a stir because researcher there's a +researcher in China who has claimed to + + align:start position:0% +researcher in China who has claimed to + + + align:start position:0% +researcher in China who has claimed to +have made the first Jean edited baby + + align:start position:0% +have made the first Jean edited baby + + + align:start position:0% +have made the first Jean edited baby +perhaps you have heard of this you + + align:start position:0% +perhaps you have heard of this you + + + align:start position:0% +perhaps you have heard of this you +probably have because it's been all over + + align:start position:0% +probably have because it's been all over + + + align:start position:0% +probably have because it's been all over +the news so I want you guys let's see I + + align:start position:0% +the news so I want you guys let's see I + + + align:start position:0% +the news so I want you guys let's see I +want us to debate whether we should + + align:start position:0% +want us to debate whether we should + + + align:start position:0% +want us to debate whether we should +whether sort of what are the advantages + + align:start position:0% +whether sort of what are the advantages + + + align:start position:0% +whether sort of what are the advantages +or disadvantages of gene editing or + + align:start position:0% +or disadvantages of gene editing or + + + align:start position:0% +or disadvantages of gene editing or +human cloning you could talk about both + + align:start position:0% +human cloning you could talk about both + + + align:start position:0% +human cloning you could talk about both +and then I want you guys to be able to + + align:start position:0% +and then I want you guys to be able to + + + align:start position:0% +and then I want you guys to be able to +kind of like present them to me I'll + + align:start position:0% +kind of like present them to me I'll + + + align:start position:0% +kind of like present them to me I'll +write them down and we'll have a + + align:start position:0% +write them down and we'll have a + + + align:start position:0% +write them down and we'll have a +discussion about it + + align:start position:0% + + + + align:start position:0% + +near this discussion sort of outside + + align:start position:0% +near this discussion sort of outside + + + align:start position:0% +near this discussion sort of outside +class I think it's really interesting + + align:start position:0% +class I think it's really interesting + + + align:start position:0% +class I think it's really interesting +and it's going to be something that + + align:start position:0% +and it's going to be something that + + + align:start position:0% +and it's going to be something that +you're gonna hear a lot about in the + + align:start position:0% +you're gonna hear a lot about in the + + + align:start position:0% +you're gonna hear a lot about in the +coming year as I'm sure + + align:start position:0% + + + + align:start position:0% + +you \ No newline at end of file diff --git a/aeQA5d3gZTI.txt b/aeQA5d3gZTI.txt new file mode 100644 index 0000000000000000000000000000000000000000..0ce6298ecbb626a4ae44a772273c357ee9e36761 --- /dev/null +++ b/aeQA5d3gZTI.txt @@ -0,0 +1,1339 @@ +align:start position:0% + +welcome back to recitation in this video + + align:start position:0% +welcome back to recitation in this video + + + align:start position:0% +welcome back to recitation in this video +segment we're going to look at the chain + + align:start position:0% +segment we're going to look at the chain + + + align:start position:0% +segment we're going to look at the chain +Rule and specifically we're going to + + align:start position:0% +Rule and specifically we're going to + + + align:start position:0% +Rule and specifically we're going to +answer a question that I've placed on + + align:start position:0% +answer a question that I've placed on + + + align:start position:0% +answer a question that I've placed on +the board I want you to find two values + + align:start position:0% +the board I want you to find two values + + + align:start position:0% +the board I want you to find two values +for Theta so that DD Theta of the + + align:start position:0% +for Theta so that DD Theta of the + + + align:start position:0% +for Theta so that DD Theta of the +function cosine 2 Theta 4th equals z at + + align:start position:0% +function cosine 2 Theta 4th equals z at + + + align:start position:0% +function cosine 2 Theta 4th equals z at +this point I should also point out a few + + align:start position:0% +this point I should also point out a few + + + align:start position:0% +this point I should also point out a few +things one Theta is is a variable in + + align:start position:0% +things one Theta is is a variable in + + + align:start position:0% +things one Theta is is a variable in +this case and if you haven't seen it + + align:start position:0% +this case and if you haven't seen it + + + align:start position:0% +this case and if you haven't seen it +before frequently we use it when we're + + align:start position:0% +before frequently we use it when we're + + + align:start position:0% +before frequently we use it when we're +dealing with trigonometric functions + + align:start position:0% +dealing with trigonometric functions + + + align:start position:0% +dealing with trigonometric functions +Theta often represents the variable + + align:start position:0% +Theta often represents the variable + + + align:start position:0% +Theta often represents the variable +that's that measures angle so if you + + align:start position:0% +that's that measures angle so if you + + + align:start position:0% +that's that measures angle so if you +haven't seen Theta before this is what + + align:start position:0% +haven't seen Theta before this is what + + + align:start position:0% +haven't seen Theta before this is what +it looks like that's how you say it and + + align:start position:0% +it looks like that's how you say it and + + + align:start position:0% +it looks like that's how you say it and +I'm actually doing the same things we've + + align:start position:0% +I'm actually doing the same things we've + + + align:start position:0% +I'm actually doing the same things we've +done before I'm taking the derivative + + align:start position:0% +done before I'm taking the derivative + + + align:start position:0% +done before I'm taking the derivative +with respect to the variable Theta of a + + align:start position:0% +with respect to the variable Theta of a + + + align:start position:0% +with respect to the variable Theta of a +function of theta the other thing I want + + align:start position:0% +function of theta the other thing I want + + + align:start position:0% +function of theta the other thing I want +to point out which I think we know + + align:start position:0% +to point out which I think we know + + + align:start position:0% +to point out which I think we know +already but just to be sure is that this + + align:start position:0% +already but just to be sure is that this + + + align:start position:0% +already but just to be sure is that this +squar here cosine squ Theta to 4 + + align:start position:0% +squar here cosine squ Theta to 4 + + + align:start position:0% +squar here cosine squ Theta to 4 +means I'm taking cosine OFA 4 and I'm + + align:start position:0% +means I'm taking cosine OFA 4 and I'm + + + align:start position:0% +means I'm taking cosine OFA 4 and I'm +actually squaring it so with that + + align:start position:0% +actually squaring it so with that + + + align:start position:0% +actually squaring it so with that +knowledge I would like us to use the + + align:start position:0% +knowledge I would like us to use the + + + align:start position:0% +knowledge I would like us to use the +chain rule to find two values for Theta + + align:start position:0% +chain rule to find two values for Theta + + + align:start position:0% +chain rule to find two values for Theta +where this derivative is equal to zero + + align:start position:0% +where this derivative is equal to zero + + + align:start position:0% +where this derivative is equal to zero +so I'll give you a moment to to take a + + align:start position:0% +so I'll give you a moment to to take a + + + align:start position:0% +so I'll give you a moment to to take a +stab at finding the derivative uh + + align:start position:0% +stab at finding the derivative uh + + + align:start position:0% +stab at finding the derivative uh +setting it equal to zero and finding + + align:start position:0% +setting it equal to zero and finding + + + align:start position:0% +setting it equal to zero and finding +some values for Theta uh that make this + + align:start position:0% +some values for Theta uh that make this + + + align:start position:0% +some values for Theta uh that make this +that make this equation this uh the + + align:start position:0% +that make this equation this uh the + + + align:start position:0% +that make this equation this uh the +derivative equals zero and um and we'll + + align:start position:0% +derivative equals zero and um and we'll + + + align:start position:0% +derivative equals zero and um and we'll +come back and then I'll work it out as + + align:start position:0% +come back and then I'll work it out as + + + align:start position:0% +come back and then I'll work it out as +well okay so the first thing we + + align:start position:0% +well okay so the first thing we + + + align:start position:0% +well okay so the first thing we +obviously need to do is be able to take + + align:start position:0% +obviously need to do is be able to take + + + align:start position:0% +obviously need to do is be able to take +the derivative of this function on the + + align:start position:0% +the derivative of this function on the + + + align:start position:0% +the derivative of this function on the +left hand side and I should say it's a + + align:start position:0% +left hand side and I should say it's a + + + align:start position:0% +left hand side and I should say it's a +little more complicated than than an + + align:start position:0% +little more complicated than than an + + + align:start position:0% +little more complicated than than an +example you saw in the lecture because + + align:start position:0% +example you saw in the lecture because + + + align:start position:0% +example you saw in the lecture because +in the lecture you were given an example + + align:start position:0% +in the lecture you were given an example + + + align:start position:0% +in the lecture you were given an example +with just two functions so I want to + + align:start position:0% +with just two functions so I want to + + + align:start position:0% +with just two functions so I want to +write it a little differently just to + + align:start position:0% +write it a little differently just to + + + align:start position:0% +write it a little differently just to +show very obviously what the three + + align:start position:0% +show very obviously what the three + + + align:start position:0% +show very obviously what the three +functions are we're composing so this + + align:start position:0% +functions are we're composing so this + + + align:start position:0% +functions are we're composing so this +function I can rewrite it as cosine of + + align:start position:0% +function I can rewrite it as cosine of + + + align:start position:0% +function I can rewrite it as cosine of +theta to the + + align:start position:0% +theta to the + + + align:start position:0% +theta to the +4th does that look like a four there we + + align:start position:0% +4th does that look like a four there we + + + align:start position:0% +4th does that look like a four there we +we + + align:start position:0% +we + + + align:start position:0% +we +go and then I square that whole thing + + align:start position:0% +go and then I square that whole thing + + + align:start position:0% +go and then I square that whole thing +that's really what the function is okay + + align:start position:0% +that's really what the function is okay + + + align:start position:0% +that's really what the function is okay +so we can see what is the outermost + + align:start position:0% +so we can see what is the outermost + + + align:start position:0% +so we can see what is the outermost +function here the outermost function is + + align:start position:0% +function here the outermost function is + + + align:start position:0% +function here the outermost function is +actually the quantity of something + + align:start position:0% +actually the quantity of something + + + align:start position:0% +actually the quantity of something +squared so the outermost function is x s + + align:start position:0% +squared so the outermost function is x s + + + align:start position:0% +squared so the outermost function is x s +what's the next function in in this + + align:start position:0% +what's the next function in in this + + + align:start position:0% +what's the next function in in this +composition the next function in is the + + align:start position:0% +composition the next function in is the + + + align:start position:0% +composition the next function in is the +cosine function and then the last + + align:start position:0% +cosine function and then the last + + + align:start position:0% +cosine function and then the last +function in is the function taking + + align:start position:0% +function in is the function taking + + + align:start position:0% +function in is the function taking +something raising it to the fourth so + + align:start position:0% +something raising it to the fourth so + + + align:start position:0% +something raising it to the fourth so +it's it's very you understand sort of + + align:start position:0% +it's it's very you understand sort of + + + align:start position:0% +it's it's very you understand sort of +the composition which is the outermost + + align:start position:0% +the composition which is the outermost + + + align:start position:0% +the composition which is the outermost +function which is the innermost function + + align:start position:0% +function which is the innermost function + + + align:start position:0% +function which is the innermost function +um in order to do this this chain Rule + + align:start position:0% +um in order to do this this chain Rule + + + align:start position:0% +um in order to do this this chain Rule +now as you saw in recitation um you were + + align:start position:0% +now as you saw in recitation um you were + + + align:start position:0% +now as you saw in recitation um you were +given the example uh do y you had Y is a + + align:start position:0% +given the example uh do y you had Y is a + + + align:start position:0% +given the example uh do y you had Y is a +function of T sorry not in recitation in + + align:start position:0% +function of T sorry not in recitation in + + + align:start position:0% +function of T sorry not in recitation in +the lecture you were given um you were + + align:start position:0% +the lecture you were given um you were + + + align:start position:0% +the lecture you were given um you were +given y as a function of t or a function + + align:start position:0% +given y as a function of t or a function + + + align:start position:0% +given y as a function of t or a function +of X and then you had to put one other + + align:start position:0% +of X and then you had to put one other + + + align:start position:0% +of X and then you had to put one other +variable in the middle here we're going + + align:start position:0% +variable in the middle here we're going + + + align:start position:0% +variable in the middle here we're going +to have a composition of three functions + + align:start position:0% +to have a composition of three functions + + + align:start position:0% +to have a composition of three functions +so we need to have two other things sort + + align:start position:0% +so we need to have two other things sort + + + align:start position:0% +so we need to have two other things sort +of in the middle so let's let's write + + align:start position:0% +of in the middle so let's let's write + + + align:start position:0% +of in the middle so let's let's write +this out first the outermost function we + + align:start position:0% +this out first the outermost function we + + + align:start position:0% +this out first the outermost function we +we'll call the whole thing y so Y is + + align:start position:0% +we'll call the whole thing y so Y is + + + align:start position:0% +we'll call the whole thing y so Y is +equal to X2 is the outermost function so + + align:start position:0% +equal to X2 is the outermost function so + + + align:start position:0% +equal to X2 is the outermost function so +then this whole thing is X now so then + + align:start position:0% +then this whole thing is X now so then + + + align:start position:0% +then this whole thing is X now so then +we'll write X is equal to cosine of + + align:start position:0% +we'll write X is equal to cosine of + + + align:start position:0% +we'll write X is equal to cosine of +w okay and then + + align:start position:0% +w okay and then + + + align:start position:0% +w okay and then +W is equal to Theta to the 4th okay + + align:start position:0% +W is equal to Theta to the 4th okay + + + align:start position:0% +W is equal to Theta to the 4th okay +again this is this this is what you saw + + align:start position:0% +again this is this this is what you saw + + + align:start position:0% +again this is this this is what you saw +before um in the lecture so you write + + align:start position:0% +before um in the lecture so you write + + + align:start position:0% +before um in the lecture so you write +the outermost function and then that + + align:start position:0% +the outermost function and then that + + + align:start position:0% +the outermost function and then that +function is a function of cosine of + + align:start position:0% +function is a function of cosine of + + + align:start position:0% +function is a function of cosine of +another one cosine of w and W is a + + align:start position:0% +another one cosine of w and W is a + + + align:start position:0% +another one cosine of w and W is a +function of theta the 4 so if I put all + + align:start position:0% +function of theta the 4 so if I put all + + + align:start position:0% +function of theta the 4 so if I put all +these back together I have Theta to the + + align:start position:0% +these back together I have Theta to the + + + align:start position:0% +these back together I have Theta to the +4th in here and then I square that and I + + align:start position:0% +4th in here and then I square that and I + + + align:start position:0% +4th in here and then I square that and I +come back to the to the function I + + align:start position:0% +come back to the to the function I + + + align:start position:0% +come back to the to the function I +wanted now we know from the lecture what + + align:start position:0% +wanted now we know from the lecture what + + + align:start position:0% +wanted now we know from the lecture what +we need to do to find essentially Dy D + + align:start position:0% +we need to do to find essentially Dy D + + + align:start position:0% +we need to do to find essentially Dy D +Theta that's what we're looking + + align:start position:0% + + + + align:start position:0% + +for okay so Dy D Theta you'll see you + + align:start position:0% +for okay so Dy D Theta you'll see you + + + align:start position:0% +for okay so Dy D Theta you'll see you +remember from the lecture it should be + + align:start position:0% +remember from the lecture it should be + + + align:start position:0% +remember from the lecture it should be +Dy DX time DX + + align:start position:0% +Dy DX time DX + + + align:start position:0% +Dy DX time DX +DW time + + align:start position:0% +DW time + + + align:start position:0% +DW time +DW D + + align:start position:0% +DW D + + + align:start position:0% +DW D +Theta okay so it's slightly more + + align:start position:0% +Theta okay so it's slightly more + + + align:start position:0% +Theta okay so it's slightly more +complicated than we saw before because + + align:start position:0% +complicated than we saw before because + + + align:start position:0% +complicated than we saw before because +there's one more term okay so now let's + + align:start position:0% +there's one more term okay so now let's + + + align:start position:0% +there's one more term okay so now let's +work out what these are well dydx is + + align:start position:0% +work out what these are well dydx is + + + align:start position:0% +work out what these are well dydx is +fairly straightforward dydx is just + + align:start position:0% + + + + align:start position:0% + +2X and then DX DW well what's the + + align:start position:0% +2X and then DX DW well what's the + + + align:start position:0% +2X and then DX DW well what's the +derivative of the cosine function the + + align:start position:0% +derivative of the cosine function the + + + align:start position:0% +derivative of the cosine function the +derivative of cosine is negative sign so + + align:start position:0% +derivative of cosine is negative sign so + + + align:start position:0% +derivative of cosine is negative sign so +this is times negative s of + + align:start position:0% +this is times negative s of + + + align:start position:0% +this is times negative s of +w times and what's DW D Theta so w is + + align:start position:0% +w times and what's DW D Theta so w is + + + align:start position:0% +w times and what's DW D Theta so w is +the function Theta to the 4th so DW D + + align:start position:0% +the function Theta to the 4th so DW D + + + align:start position:0% +the function Theta to the 4th so DW D +Theta is 4 Theta to the thir now when + + align:start position:0% +Theta is 4 Theta to the thir now when + + + align:start position:0% +Theta is 4 Theta to the thir now when +you look at this you should + + align:start position:0% +you look at this you should + + + align:start position:0% +you look at this you should +remember X we sort of inserted into the + + align:start position:0% +remember X we sort of inserted into the + + + align:start position:0% +remember X we sort of inserted into the +problem to make the problem easier and W + + align:start position:0% +problem to make the problem easier and W + + + align:start position:0% +problem to make the problem easier and W +we inserted into the problem to make the + + align:start position:0% +we inserted into the problem to make the + + + align:start position:0% +we inserted into the problem to make the +problem easier for us to follow so we + + align:start position:0% +problem easier for us to follow so we + + + align:start position:0% +problem easier for us to follow so we +don't want all these x's and W's we want + + align:start position:0% +don't want all these x's and W's we want + + + align:start position:0% +don't want all these x's and W's we want +everything in terms of in terms of theta + + align:start position:0% +everything in terms of in terms of theta + + + align:start position:0% +everything in terms of in terms of theta +right but what is w Well w is Theta to + + align:start position:0% +right but what is w Well w is Theta to + + + align:start position:0% +right but what is w Well w is Theta to +the 4th so I can replace that by Theta + + align:start position:0% +the 4th so I can replace that by Theta + + + align:start position:0% +the 4th so I can replace that by Theta +to the 4th and what is X x is cosine W + + align:start position:0% +to the 4th and what is X x is cosine W + + + align:start position:0% +to the 4th and what is X x is cosine W +but W is Theta to the 4th so X is + + align:start position:0% +but W is Theta to the 4th so X is + + + align:start position:0% +but W is Theta to the 4th so X is +actually cosine of theta to 4th okay so + + align:start position:0% +actually cosine of theta to 4th okay so + + + align:start position:0% +actually cosine of theta to 4th okay so +I get 2 cosine of + + align:start position:0% + + + + align:start position:0% + +4 Time s w again iset 4th of theta to + + align:start position:0% +4 Time s w again iset 4th of theta to + + + align:start position:0% +4 Time s w again iset 4th of theta to +4th Time 4 Theta to the 3 and let's make + + align:start position:0% +4th Time 4 Theta to the 3 and let's make + + + align:start position:0% +4th Time 4 Theta to the 3 and let's make +this nicer I'll bring the coefficient + + align:start position:0% +this nicer I'll bring the coefficient + + + align:start position:0% +this nicer I'll bring the coefficient +and the Theta to the 3 in front and this + + align:start position:0% +and the Theta to the 3 in front and this + + + align:start position:0% +and the Theta to the 3 in front and this +minus sign in front I get -8 Theta to + + align:start position:0% +minus sign in front I get -8 Theta to + + + align:start position:0% +minus sign in front I get -8 Theta to +the + + align:start position:0% +the + + + align:start position:0% +the +3 cosine of theta to + + align:start position:0% +3 cosine of theta to + + + align:start position:0% +3 cosine of theta to +4th s of theta to 4th + + align:start position:0% +4th s of theta to 4th + + + align:start position:0% +4th s of theta to 4th +okay and then the problem asked to find + + align:start position:0% +okay and then the problem asked to find + + + align:start position:0% +okay and then the problem asked to find +where the derivative is equal to zero + + align:start position:0% +where the derivative is equal to zero + + + align:start position:0% +where the derivative is equal to zero +find two values now why did I ask you to + + align:start position:0% +find two values now why did I ask you to + + + align:start position:0% +find two values now why did I ask you to +find two values because one is very easy + + align:start position:0% +find two values because one is very easy + + + align:start position:0% +find two values because one is very easy +if this thing is set equal to zero one + + align:start position:0% +if this thing is set equal to zero one + + + align:start position:0% +if this thing is set equal to zero one +value should stand out right away for + + align:start position:0% +value should stand out right away for + + + align:start position:0% +value should stand out right away for +Theta that makes uh makes this this + + align:start position:0% +Theta that makes uh makes this this + + + align:start position:0% +Theta that makes uh makes this this +product Zer and that is theta equals z + + align:start position:0% +product Zer and that is theta equals z + + + align:start position:0% +product Zer and that is theta equals z +so theta equals z is our EAS easiest + + align:start position:0% + + + + align:start position:0% + +answer okay so if you didn't do that + + align:start position:0% +answer okay so if you didn't do that + + + align:start position:0% +answer okay so if you didn't do that +then you wanted the more challenging you + + align:start position:0% +then you wanted the more challenging you + + + align:start position:0% +then you wanted the more challenging you +could have done it done the other things + + align:start position:0% +could have done it done the other things + + + align:start position:0% +could have done it done the other things +also so what about cosine Theta 4th if + + align:start position:0% +also so what about cosine Theta 4th if + + + align:start position:0% +also so what about cosine Theta 4th if +we want a product of three things to be + + align:start position:0% +we want a product of three things to be + + + align:start position:0% +we want a product of three things to be +zero then at least one of them has to be + + align:start position:0% +zero then at least one of them has to be + + + align:start position:0% +zero then at least one of them has to be +zero so I could have set cosine Theta to + + align:start position:0% +zero so I could have set cosine Theta to + + + align:start position:0% +zero so I could have set cosine Theta to +4th equal to + + align:start position:0% + + + + align:start position:0% + +zero and for what values of of an angle + + align:start position:0% +zero and for what values of of an angle + + + align:start position:0% +zero and for what values of of an angle +I should just say for what values of + + align:start position:0% +I should just say for what values of + + + align:start position:0% +I should just say for what values of +theta to 4th is this going to be zero + + align:start position:0% +theta to 4th is this going to be zero + + + align:start position:0% +theta to 4th is this going to be zero +well this means that Theta the 4 + + align:start position:0% +well this means that Theta the 4 + + + align:start position:0% +well this means that Theta the 4 +4 is equal + + align:start position:0% +4 is equal + + + align:start position:0% +4 is equal +to either maybe pi/ 2 or you could add + + align:start position:0% +to either maybe pi/ 2 or you could add + + + align:start position:0% +to either maybe pi/ 2 or you could add +another Pi okay so we could say Pi well + + align:start position:0% +another Pi okay so we could say Pi well + + + align:start position:0% +another Pi okay so we could say Pi well +let's let's just say that's one example + + align:start position:0% +let's let's just say that's one example + + + align:start position:0% +let's let's just say that's one example +Theta to 4 equals pi over 2 would work + + align:start position:0% +Theta to 4 equals pi over 2 would work + + + align:start position:0% +Theta to 4 equals pi over 2 would work +right because cosine of pi/ 2 is equal + + align:start position:0% +right because cosine of pi/ 2 is equal + + + align:start position:0% +right because cosine of pi/ 2 is equal +to zero okay and so then we could have + + align:start position:0% +to zero okay and so then we could have + + + align:start position:0% +to zero okay and so then we could have +said Theta is equal to pi over + + align:start position:0% +said Theta is equal to pi over + + + align:start position:0% +said Theta is equal to pi over +2 to the + + align:start position:0% +2 to the + + + align:start position:0% +2 to the +1/4 okay that's another that's another + + align:start position:0% +1/4 okay that's another that's another + + + align:start position:0% +1/4 okay that's another that's another +example there we could have also done um + + align:start position:0% +example there we could have also done um + + + align:start position:0% +example there we could have also done um +we could have added pi to this and + + align:start position:0% +we could have added pi to this and + + + align:start position:0% +we could have added pi to this and +gotten another answer but I only asked + + align:start position:0% +gotten another answer but I only asked + + + align:start position:0% +gotten another answer but I only asked +for two so I guess that I'm allowed to + + align:start position:0% +for two so I guess that I'm allowed to + + + align:start position:0% +for two so I guess that I'm allowed to +stop there \ No newline at end of file diff --git a/ajXDBKIJsJ8.txt b/ajXDBKIJsJ8.txt new file mode 100644 index 0000000000000000000000000000000000000000..70573b2e3ef1eb1fc4229ff6c58881c7021c3337 --- /dev/null +++ b/ajXDBKIJsJ8.txt @@ -0,0 +1,3189 @@ +The following content is +provided under a Creative + +Commons license. + +Your support will help MIT +OpenCourseWare continue to + +offer high quality educational +resources for free. + +To make a donation or view +additional materials from + +hundreds of MIT courses, visit +MIT OpenCourseWare at + +ocw.mit.edu. + +PROFESSOR: All right. + +Can everyone hear me? + +So I guess it's 2:35, and we +might as well get started. + +So the calendar, I think, still +says that we have a + +guest lecture today but sorry to +disappoint you, there is no + +guest lecture. + +Instead we have a quiz for +you on Thursday, which is + +so much more fun. + +Not really. + +But I do realize that everybody +has a lot to do, + +even just for this class. + +You guys have your final +project and so on. + +So hopefully this +will be helpful. + +It won't take the entire 1 and +1/2 hours, I don't think. + +And the remaining time will be +up in office hours, answering + +questions about stuff. + +So the first thing is I decided +to run some stats that + +we haven't run before +for this class. + +These are your Project 42 +4.2 final submissions. + +And in the red are your beta +submission run times. + +And in the blue are your +corresponding final + +submission run times. + +I thought it was just +interesting to see some groups + +did massive improvements, while +others didn't really + +change their programs much. + +And just to give you an idea, +a 90% for your performance + +grade is indicated by that +green line and below. + +So the majority of the class +did really well. + +All right. + +So the thing that everybody's +concerned about. + +So Quiz 2 will be in lecture +on Thursday. + +It'll be an 80 minute quiz, +similar in format to the + +previous one. + +And you guys once again are +allowed a one-page handwritten + +crib sheet. + +And it covers everything that +has been done since Quiz 1. + +It's not designed to be +cumulative, but unfortunately + +due to the nature of the class, +there's going to be + +some things from the previous +part of the class that you + +would need to know or it would +be helpful to know. + +Unlike last time, we didn't +post a practice quiz on + +Stellar, because it turns out +that the material and the + +order of the material gets +shuffled around quite a bit + +every year. + +And we have different focuses. + +So posting a practice quiz would +actually be pretty mean, + +because it would cause +you guys to study the + +wrong things instead. + +Instead I try to extract the +most useful things from our + +discussions of what the quiz +is going to be this time. + +So hopefully all this +information is helpful. + +Feel free to interrupt +me at any + +time if you have questions. + +So the first part, I would +roughly call analyzing and + +possibly writing parallel +programs. + +And to start off, is everybody +familiar with what one of + +these graphs represents? + +So you have work and then +each circle is a + +unit amount of work. + +And then the graph shows the +dependencies of the things. + +So just to start off with a +really simple question, what + +is the total amount of +work represented? + +AUDIENCE: [LAUGHTER] + +PROFESSOR: Uh oh. + +I heard 17, which is not what I +got when I counted this last + +night at 2:00. + +AUDIENCE: 26. + +AUDIENCE: 24. + +PROFESSOR: I like 24. + +AUDIENCE: [LAUGHTER] + +PROFESSOR: And I'm going to +assume it's 24, and not + +embarrass myself by trying +to count it. + +Now what is the span? + +AUDIENCE: 8. + +AUDIENCE: 8. + +AUDIENCE: 8. + +PROFESSOR: 8 sounds right. + +So the longest path-- there's +actually a couple different + +paths that end up being 8, but +I think 8's the right answer. + +So then parallelism? + +AUDIENCE: 3. + +PROFESSOR: Cool. + +All right. + +So now that we're done with +that, how about a little bit + +of background on caches. + +So when you run programs in +parallel, it causes some more + +interesting things to happen in +cache that did not happen + +with serial execution. + +One of those things +is true sharing-- + +cache misses-- which are +caused when multiple + +processors, like multiple +threads, are trying to operate + +on the same piece of +data in memory. + +So as a result, your cache would +be forced to synchronize + +that cache line and +move it across-- + +copy it from the freshest +processor to the other ones + +every time that it's +requested. + +And you end up with a lot +of overhead generated by + +continually doing +these copies. + +So ideally you don't +want to do this. + +But it's a lot easier +said than done. + +False sharing is a little bit +trickier because it's not + +immediately apparent from +looking at your program that + +you're having multiple +threads do the-- + +operate on the same data. + +Instead with false sharing, you +have multiple processors + +that want to operate on +different locations in memory. + +But due to the way that your +computer's cache is organized, + +they just happen to be in +the same cache line. + +As a result, you end up with +the same memory, the same + +overhead, that you would +see with true sharing. + +But when you look at the code +itself, you don't think that + +you're doing anything that +involves multiple threads + +operating on the same data. + +And so with that, here's +a piece of code. + +And my question is this true +sharing or false sharing? + +Let's take a vote. + +How many people think +it's true sharing? + +Nobody. + +Well, how many people think +it's false sharing? + +Come on. + +You have to vote one +way or another. + +Let's try this again. + +True sharing? + +False sharing? + +That's better. + +All right, so it is indeed +false sharing. + +And can someone propose +a solution to fix it? + +Yes? + +AUDIENCE: Separate A +and B, and put them + +in different shelves. + +PROFESSOR: Would that +be sufficient? + +Putting them in different +trucks? + +AUDIENCE: Then, padding +the trucks. + +PROFESSOR: Yeah. + +Maybe with a little +bit of padding, + +depending on your system. + +But sure, I'll accept that. + +But on the quiz, you might be +asked to propose solutions to + +problems that you find. + +And hopefully those +will be easier. + +Now on to a more fun topic-- + +synchronization. + +Yes? + +AUDIENCE: I have a question +on sharing. + +So if two programs only access +data, does that still count ? + +PROFESSOR: If you only access +the data and nothing in the + +cache line is being modified, +then you're safe, because + +every processor can +independently read from their + +own copy of that. + +AUDIENCE: So that +doesn't count. + +PROFESSOR: That doesn't +count, correct. + +But the problem is if your cache +line is 64 kilobytes, + +and any thread on any processor +changes one piece of + +data inside that cache, +then everybody + +has to pull new copies. + +So the classic example to +demonstrate synchronization + +correctness is the dining +philosophers problem, where + +you have n-- + +I believe five in this case-- + +philosophers, and +five chopsticks. + +And each philosopher +has to eat. + +So they use mutexes to-- + +well, generally you need-- + +each philosopher's code would be +pick up two chopsticks and + +then eat and then put down +their two chopsticks. + +It's somewhat of a contrived +example, but it actually comes + +up in a lot of cases. + +And one of the cases where it +comes up is in the system that + +I use to grade your +unit tests. + +So I got impatient about +running 200 or so + +unit test in series. + +And since I had about 200 cores +altogether on the cloud + +machines, I figured, why not +do them in parallel? + +But the problem is I need to +run-- if I have students A and + +B, I need to run student A's +test against student B's + +implementation. + +So the rough way that I did that +was I grabbed a lock on + +student A's repository, grabbed +a lock on student B's + +repository, and then +modified-- + +swapped in their test files, did +all my testing, and then + +returned the files to the +original conditions, and then + +let go of the locks. + +Unfortunately, when you do that, +you run into much of the + +same problem as the dining +philosophers problems. + +So the naive strategy is for +each philosopher, you grab a + +lock on your left chopstick. + +You grab a lock on your right +one, with respect to you. + +And then you eat and then you +unlock them in the same order. + +So this has a bug. + +Can anyone point +out what it is? + +AUDIENCE: You want to unlock +in a certain order. + +PROFESSOR: Actually, it doesn't +matter which order you + +unlock in in in this case. + +So bad things happen if +everybody starts at + +the exact same time. + +So everybody grabs their left +chopstick. there's five + +people, five chopsticks, +so that works fine. + +Now everybody wants to +grab their right one, + +but it's not there. + +Because the person to the right +already grabbed it as + +their left. + +So they wait forever for the +right chopstick to appear and + +it never does. + +So the situation is +called a deadlock. + +And it's obvious to spot, +because all of your threads + +are going to be stuck doing +absolutely nothing. + +Your CPU is not doing +anything. + +And you're just sitting there. + +So a very common work-around +that people like for this is + +to use what's called +a try lock pattern. + +So what you do is you grab a +lock on one of them, like, + +say, your left one. + +And then for the right one, +instead of directly going and + +trying to grab the +lock, you ask-- + +you basically do-- + +if the thing is unlocked, +grab it. + +Otherwise, don't grab it. + +So it's a non-blocking +approach to + +trying to get a lock. + +So it either succeeds and +you have the lock, or + +it instantly fails. + +And if it fails, then you switch +the order of which-- + +you put down the chopstick that +you grabbed, and then you + +try the next one. + +Maybe you wait a little +bit before then. + +This is more or less than what +I did for your beta test, for + +your unit test tester. + +When it fails to-- + +if first grabs one student's +directory's locks. + +And then it tries to grab +the second one. + +If that fails, then it puts down +both locks, and then it + +waits a little bit, and +then it tries again. + +So what's the problem +with this approach? + +Yes? + +AUDIENCE: It can +still hold up. + +PROFESSOR: What's that? + +AUDIENCE: It can keep waiting +and grabbing, and sometimes it + +will contend. + +PROFESSOR: Yeah, pretty much, +the same problem happens. + +Only now you have the case where +everybody grabs their + +left, and now the right +one's gone. + +So they put down +their left one. + +And then they all go to +grab the right one. + +Now they have the right +one, and now they + +want the left one. + +But the left one not there. + +So in theory, they can end +up doing this for a + +very, very long time. + +But in practice what happens +is because of scheduling + +overhead, and the phase of the +moon and whatever else affects + +computing, you'll end up after +a while, this become distinct + +from this pattern and eventually +all the locks go + +through, and you're OK. + +But in the meantime, you spent a +lot of time spinning, trying + +to grab locks. + +And so this situation is +called a livelock. + +And it's a lot more +annoying than a + +deadlock because it happens-- + +it tends to be less +reproducible. + +And it's harder to diagnose, +because if you're looking at + +top or your favorite CPU +monitor, you see that the + +program seems to be +making progress. + +Maybe some of them actually get +the lock and go through. + +But the rest of them don't. + +So it's hard to argue +whether or not + +there's correctness issue. + +Now there's various classes +of solutions to the dining + +philosophers problem, but you +guys can go look that up. + +I'm not going to go over them. + +So another issue with +synchronization is suppose you + +have two threads. + +Let's say this is a Mars Rover, +and it's on Mars. + +And the two things that the +programmer wanted to do are + +send back its debugging log, so +that the nerdier people at + +NASA, I suppose, can read +them over, or whatever + +they do with logs. + +And the high priority, what +everybody actually wants, is + +for the Rover to send +back pictures. + +Now both of these things require +access to the radio + +that's supposed to transfer +something. + +And only one thing can +transmit at time. + +Otherwise, the transmission +is garbled. + +So a reasonable approach might +be to just lock the radio in + +each thread before you transmit, +and then unlock + +after you transmit. + +So what could be a potential +issue with this? + +AUDIENCE: One might +get all the time. + +PROFESSOR: Let's say, the +scheduler interrupts every 10 + +milliseconds, and then 1 out of +the 10 times, it allows 10 + +logs to run. + +And then 9 out of the 10 times, +it will allow some + +pictures to run. + +So everybody gets +time scheduled. + +So I guess the easiest way to +illustrate this is what + +happens if it's currently +running said logs, and it + +grabs this lock. + +And then while it's +transmitting, let's say on the + +second megabyte, the scheduler +says your time is up. + +And then it swaps in this +program, and it tries to run. + +So now when this program runs, +it tries to lock the radio, + +but the radio's already +locked. + +And the one that locked +the radio is + +the send locks thread. + +And so it could sit there and +spin for a while waiting for + +the lock to be available. + +But that's not going +to happen. + +Because the guy that's holding +the lock is a bug. + +So in general, this is called +starvation, where in the + +process of having a shared +resource, you end up unfairly + +depriving someone else of +a resource when you're + +not truly using it. + +Well, I guess that's not the-- + +I guess you are using it, but +you're using it for longer + +than is fair for you. + +Like in the scheduler you wanted +90% to one process and + +10% to the other, but in reality +you end up with a + +completely different +set of priorities. + +And this inversion of priorities +is commonly called + +priority inversion. + +Does that make sense? + +Cool. + +So on a completely +different topic. + +So Cilk hyperobjects +were covered + +extensively in lecture. + +You guys had a problem set on +it, although it was not + +received very warmly from +what I see in the + +problems sets write ups. + +But I think all of the basic +material for what a Cilk + +hyperobjects is and what it +does can be found in the + +lecture material. + +But more interesting, let's +explore what you can do with + +hyperobjects that aren't +in the documentation. + +So I'm going to define +a piece of code here. + +And it's C++ or Cilk++ code. + +And the first part of it +defines a very simple + +structure called a point. + +And it has three members. + +Or actually it has two members, +x and y, and it has + +three methods for setting the +values of x and y and also + +getting the values of x and y. + +Question? + +No? + +OK. + +And then there's also a +hyperpoint class which + +contains some extra Cilk junk. + +And it also implements the +same three methods. + +Set, get x, and get y. + +And if you look at the monoid +that it contains the point + +monoid it implements a +reduce function that + +just doesn't do anything. + +And for the public methods, the +setters and getters, they + +grab the point represented by +the local view to the reducer + +that it contains. + +And it calls the method that +you called on that point. + +So the question is what +does this thing do, + +the hyperpoint object? + +Anybody have any wild guesses +at this point? + +That's a no. + +So OK. + +Let's try using this code. + +So to put the example +into perspective. + +Suppose I have this artificially +contrived + +function that takes an array of +100 points, and it tries to + +do an in place reversal +of its elements. + +So one way that it can +do that is you have a + +global temporary point. + +And you, at every step of the +iteration, first you step + +through half of the list. + +And then at every step of the +iteration, you copy the ith + +element into the temporary +variable. + +And then you set the ith from +the other end to the-- + +you swap the two. + +And then you-- + +yeah, so if it is a +three-variable swap, I guess + +is the simplest way +of explaining it. + +It's a swap using a using +a temporary variable. + +Anyone not get what that code +does, despite my attempts to + +confuse you? + +So as far as this space +complexity of this procedure, + +really what it needs at minimum +is enough memory to + +store the temporary point, and +then one register to use to + +put in the temporary values. + +You can think of a solution that +uses only one register to + +update values within your +point structure. + +And so let's suppose I want +to do this in parallel. + +And so what I do is I call it +parallel reverse, and I + +replace for with Cilk for. + +So am I done? + +What's wrong with my code? + +AUDIENCE: Race. + +PROFESSOR: Yes. + +Well first it takes that much-- +it takes the same + +amount of space. + +But there is a data race on +temp, because multiple threads + +could be updating temp. + +So now what I do is I replace +my point with a hyperpoint. + +So now what does the +hyperpoint do? + +So within each iteration of the +Cilk for loop, so if that + +iteration has been-- if the +work of that iteration has + +been stolen or spawned off. + +Then the hyperobject, because +it has a reducer within it, + +it'll get a new local +view which is a new + +point object to use. + +And if it's not still in that +it continues running in the + +same thread, then it actually +just continues using the local + +view that was previously +instantiated. + +So no matter what Cilk does +in the background, you're + +guaranteed to not have any data +races on temp, because + +whenever you spawn off a new +thread, the hyperobject will + +instantiate a new temp object +for you to use. + +And this is an example of what's +called thread local + +storage, so like a temporary +storage space for each thread. + +Any questions? + +Cool. + +So on the quiz, you might be +asked about various abusing of + +various other novel hyperobjects +that don't do the + +typical thing, which +is take a left and + +right and reduce them. + +They might do something +a little bit quirky. + +And you might be asked to +explain what they do. + +AUDIENCE: Maybe? + +PROFESSOR: Yes? + +Maybe. + +Maybe. + +AUDIENCE: But this is purely for +illustrating that you can + +do such a thing with +hyperobjects. + +Because you can always create +a temporary variable there. + +PROFESSOR: But suppose point +was a much larger object. + +Sure, this is a contrived +example. + +But yes. + +Anyone? + +Everyone gets this? + +So, in that case, why would that +problem be more efficient + +than creating a new copy of +it, say another point? + +PROFESSOR: Because if you think +about the case where + +this code runs on a single +processor with no work + +stealing, this version does the +exact same thing as the + +single threaded version. + +No extra objects are +being created. + +And if you're running on however +many processors and + +Cilk decides what to do in the +background as far as how many + +threads to allocate for you, and +your code doesn't have to + +know anything about that. + +AUDIENCE: What's the +monoid again? + +PROFESSOR: The monoid is the +associative operator that has + +an identity and a reduce +operation and some other + +things that I forgot. + +Any more questions? + +Cool. + +So switching gears, and this +time I actually have a + +placeholder slide for it, next +part is more about like the + +types of things that you might +have learned from doing or + +experience you might +have gained + +from doing your projects. + +And it primarily pertains to lab +oriented, like in practice + +hands on things, as opposed +to theoretical concepts. + +So just as a fun warm up, +everybody has hopefully at + +this point used some +STL data structure. + +Vectors should definitely +look familiar. + +So let's compare some operations +on these three. + +Because, as far as the API +is concerned, both list-- + +all three of them support +almost the same set of + +functions, as far as Insert, +at pushback, pop front. + +All those operations are +supported by these things. + +So it's kind of-- + +You might ask why would you +use one over the other? + +Well, it turns out that they +have slightly different + +performance characteristics +that are useful in noting. + +So anyone want to compare and +contrast like what data + +structure a list corresponds +to compared to a vector? + +So which one would be +like a linked list? + +List, yep. + +And then vector obviously is a +dynamically growing array. + +And a deque-- + +how many people have +used the deque? + +Cool. + +One. + +How many people know what +deque does even if they + +haven't used it? + +Three? + +Four? + +OK. + +So a deque is actually +implemented similar to a + +vector, but it's dynamically +growing on both ends. + +OK, so let's start with +filling in the + +table for the list. + +So inserting and removing +at the end of a list. + +Constant time? + +Linear time? + +How many people say +constant time? + +Linear? + +Half and half, wow. + +Don't rely on your neighbor +during the test. + +So it's actually +constant time. + +If you think about appending to +the end of a linked list, + +it's just a matter of couple +pointer operations. + +How about inserting and +removing at the front? + +Constant? + +Cool. + +Linear? + +OK. + +I'll stop picking +on people now. + +So next is inserting and +removing an arbitrary offset. + +So what I mean by that is you +have an iterator to a + +particular point inside +the list. + +Now I say insert this element +five or n elements away from + +that iterator. + +How long does that +operation take? + +How many people say +constant time? + +Three people. + +How many people say some +sort of linear time? + +I agree with you guys. + +It is indeed a linear +time thing, + +because you have to traverse-- + +you have to actually fall the +next pointers to the location + +or the previous pointers +to the location + +that you want to insert. + +So although list might appear +to support randomish axis, + +like you can add numbers to +the iterator, it doesn't + +actually support that operation +efficiently in the + +background. + +Now the next one is also +kind of tricky. + +Checking the size. + +Like checking how many elements +are calling the dot + +size method of a +standard list. + +How many people think +that's constant? + +Cool. + +About four or five. + +How many people think +that's linear? + +One. + +How many people think it's +possible to have a linked list + +data structure that's forced +constant time? + +There we go. + +Well, unfortunately, the STL +only requires you to have a + +big O of n time for this. + +In fact, I peeked inside the +code for glibc the lib + +standard C++ that is used +on the cloud machines. + +And in fact, what they do is +they actually walk through + +everything from start to +end, and they count up + +the number of times. + +So in fact, it is a linear time +operation, although I'm + +sure somewhere out in the +world, there exists a C + +library, C++ library that does +linear time, or constant time, + +size look ups. + +So you might want to be careful +about that one. + +On a different note, there's +actually a dot empty method + +for checking whether or not a +list is empty, and for any + +type of STL collection +that is guaranteed + +to be constant time. + +So if you just want to know +whether something's empty, + +don't use dot size equals 0. + +What about reversing a +linked list in place? + +Linear? + +More than linear? + +It's not a technical term, and +Charles is probably going to + +hurt me now. + +Linear? + +Yes. + +Linear. + +What about in place sorting +of a linked list? + +How many people think +it's N log(N)? + +One or two daring souls. + +Three daring souls. + +A well informed daring soul. + +How many people think it's +more than N log(N)? + +One. + +OK. + +So actually it is N log(N). + +And that's actually not +specified by the specs. + +But it happens to be. + +And it turns out that there is +a variant merge sort that + +works on link list +that is N log(N). + +I didn't know that, +but anyway. + +So how about let's fill this +in for the vector. + +Inserting and removing an +element at the end-- + +constant time? + +Linear time? + +Nobody says linear time. + +So it's amortized constant +time, I guess. + +I'll just call it +constant time. + +What about inserting +or removing at + +the front of a vector-- + +constant time? + +Linear time? + +Come on, guys. + +I'm getting like three hands for +linear time and zero for + +constant time. + +I guess that's reasonable. + +So it does, in fact, +insert one element. + +It puts the element in and then +it grows the vector in. + +It copies everything in. + +So don't insert at the front, +don't insert or remove at the + +front of a vector. + +It's a very bad idea if +you do that a lot. + +What about inserting or removing +at an arbitrary + +location inside a vector? + +Well, that one's fairly obvious +to be some sort of + +linear time too, because it +has to shift all of the + +elements after it. + +Checking the size +of the vector? + +Some people are getting +pessimistic about the STL. + +That's my personal opinion, +but I won't + +transfer that onto you. + +So it turns out that for a +vector, yes, it is constant + +time to check the size. + +So that's OK. + +In place reversal, +linear time. + +And sorting is N log(N), +which is not + +surprising by any means. + +So a deque? + +Inserting or removing +at the end-- + +constant? + +Sure, constant. + +And inserting or removing +at the front? + +Cool. + +Constant. + +So that's the primary +difference between + +a deque and a vector. + +And for everything else, it +behaves exactly like a vector. + +Does that makes sense? + +Yes. + +AUDIENCE: So is list like +a doubly linked list? + +PROFESSOR: A standard list is in +fact a doubly linked list. + +So it supports both forward +and reverse traversal. + +There's a standard S list, which +is a singly linked list, + +and it only supports +forward traversal. + +Any other questions? + +Moving on to a slightly +different topic, can anyone + +point out what is bad +about this code? + +And I mean from a performance +standpoint. + +AUDIENCE: It's O of n. + +PROFESSOR: All right. + +Someone said it, +so it's O of n. + +So the vector that's passed in +here is passed in by value, + +which means whenever you call +this function, it'll actually + +make a brand new copy +of the vector and + +copy all of the elements. + +So it's linear time with respect +to the number of + +elements in the vector. + +PROFESSOR: So how +do you fix that? + +AUDIENCE: You can pass +in a pointer. + +PROFESSOR: So there's +two ways. + +So on the left is the original +code, and on the right are two + +different ways to pass in just +a pointer to the same thing. + +So you can do a reference +pass, which is the first + +version above. + +And then you can use a dot +to access the methods. + +Or you can pass in by pointer +which everyone is already + +familiar with. + +And that's where you +have to use arrows + +to access the elements. + +And then you also have to change +the way that you call + +the function. + +So oftentimes if you just catch +something in code, like + +say the final project where +something is passed by value, + +where it should be passed by +reference, oftentimes the + +easiest way to modify the code +is to just change it to use a + +reference rather +than a pointer. + +So the next thing that I want +to cover is a question type + +that will be on the final, +will be on the quiz. + +And I'll give some examples +of problems of this form. + +But most importantly, I want +everybody to be familiar with + +the form of the question, the +rules involving the question, + +so nobody accidentally loses +points for not reading the + +instructions, which nobody +seems to do on quizzes. + +So you are given two versions +of the same function written + +in C or C++. + +And you are to assume +that your compiler-- + +well, the compiler, as far as +like what the CPU is executing + +is a literal interpretation +of the code you + +see before and after. + +By this point, everybody is +probably familiar with some of + +the simple tricks a compiler +does, like if you say int x + +equals 1 plus 1 there is no +circumstance in which the + +compiler actually puts two 1s in +two different registers and + +tells it to add it and +then put it in x. + +So you are assuming that your +compiler is doing a literal + +translation. + +And then you are asked to +determine three properties + +about the optimization, +so going from the + +before to the after. + +So the first thing is +whether or not the + +optimization is legal. + +And when we define legal, we +mean that the optimized + +version always has the same-- + +preserves the same behavior +as the other version. + +It should be relatively simple +to infer from the code + +snippets that we give you, what +the intended purpose of a + +function is. + +And you are to determine whether +or not the optimized + +version acts like the +unoptimized version, as far as + +the correctness of the result. + +Second, you are asked to +determine whether or not this + +optimized version is faster +than the previous version. + +And by faster, we mean faster +in most conceivable cases. + +It's a short answer question so +you might want to explain + +what you mean. + +But we do expect a yes +or no answer to + +start off the question. + +And it should be pretty +clear whether the + +answer is yes or no. + +And then finally, I'm sure by +this point everybody knows + +that when you compile with gcc +-02 or -03, the compiler does + +a lot of things for you. + +So there's oftentimes no point +in writing certain + +optimizations by hand, when +you know when you hit the + +compile button, the compiler's +going to do it in the + +background anyway. + +So this question asks whether +or not you can reasonably + +assume that the optimizing +compilers, like the ones that + +you're using for your projects, +would do this + +optimization for you or should +you take the effort to + +actually do this optimization +by hand. + +And then, legalese, if the +optimization is illegal, let's + +not answer whether or not it's +faster or automatic. + +And if the optimization actually +makes things slower, + +then let's not answer whether +the compiler does it for you. + +Some of us have more cynical +views of the + +compiler than others. + +So we'll just disregard that. + +Any question on the rules? + +AUDIENCE: How are we supposed +to know what types of things + +the compiler's going to do, +can we just read the + +documentation? + +PROFESSOR: So there was a +lecture that Samaan gave + +called What Compilers +Can and Cannot Do. + +AUDIENCE: So it's just stuff +from that lecture? + +PROFESSOR: I would say most +of it is that lecture. + +And then other things-- we might +throw in a thing or two + +that you guys hopefully +learn from. + +So throughout the term, we've +been misguiding you on those + +walk through P-sets, suggesting +you to do things + +that actually don't help. + +And you guys have gotten +pretty pissed at + +us about that probably. + +But there was a method +to the madness. + +I mean, there was something to +be learned from that, whether + +or not we actually +meant to do it. + +So hopefully some level of +intuition would answer it, and + +you would get the bulk of the +points for just understanding + +the points raised +in the lecture. + +Any other questions +about the rules? + +All right. + +So I have a couple of examples +of these types of questions. + +So the first one is this. + +So it should be fairly obvious +what the code does. + +It takes your input, and it +wants to mod it by 256. + +So first question is this +a legal optimization? + +How many people say yes? + +A lot of people. + +Anybody say no? + +Reed almost scared me +for a moment there. + +He had his hand up. + +So yes, it is indeed legal. + +And it's a standard bit hack +for doing a modulo + +by a power of two. + +AUDIENCE: What if it's 257? + +PROFESSOR: I was fortunate +enough to make it a uint64. + +So next question is given that +it's legal, is it faster to do + +the and instead of the mod? + +How many people say yes? + +How many people say no? + +So a majority of the +class says yes, and + +some people say no. + +So what would be a reason why +you think it's not faster? + +AUDIENCE: Well, I didn't say +it's not faster faster. + +It's probably the same time, +because I assume the + +instruction for modding is not +actually dividing by it. + +PROFESSOR: So for the other +people who said no, how many + +people agree with that +line of reasoning? + +All right. + +Seems like everybody. + +So unfortunately, +it is faster. + +And it turns out, I compiled +down both of these pieces of + +code under-- well, actually, +the compiler-- + +but anyway, I'll get +to that next. + +Not giving away any answers. + +But so I executed the assembly +instructions corresponding to + +both of these operations. + +And it does turn out that the +compiler, the CPU, when you + +ask it to take the mod of an +arbitrary number, usually it's + +an instruction called div mod. + +And what that does is that it +does a divided by b, and it + +puts the dividend in one +register and it puts the + +modulo in another register. + +And we do that for, let's say, +2 to the 63rd modulo 256, + +because it actually goes through +all the clock cycles + +for doing that division +process. + +And then it dumps out the +modulo at the end. + +So yes, this actually does +tend to be a lot faster. + +Now next question is will the +compiler do this for you? + +How many people say yes? + +Most of the class. + +Anybody say no? + +Good. + +We all trust the compiler +to some extent. + +So yeah, it turns out that gcc, +starting from 01, will do + +this for you. + +Any questions? + +All right. + +Next question. + +So you have a list. + +And you pushed in. + +You pushed at the end. + +It's 42, twice. + +And then you returned the result +of popping the front + +element and then popping the +back element, subtracted. + +So first of all, is this +a legal operation? + +Let me give everybody +a chance to think. + +AUDIENCE: Legal optimization +as opposed to an operation. + +PROFESSOR: Yeah. + +How many people vote yes, +this is going legal? + +Roughly half the class. + +How many people say no, +this is not legal? + +Two people. + +OK, so why would it +not be legal? + +You can't do that. + +Yes? + +AUDIENCE: There happens to be +wastefulness on some problems. + +PROFESSOR: Well, that could +certainly happen. + +But for the purpose of +these problems-- + +see this is why I'm bringing up +these problems-- so for the + +purpose of these problems, +assume there's no man behind + +the curtain doing things. + +For any given problem, you +could say that's someone + +attaching a debugger to your +program and changing the + +memory between instructions. + +So let's just assume +that's happening. + +AUDIENCE: Also, who's +local, right? + +PROFESSOR: Yeah. + +Yea, Foo is actually local, +so if anybody else's doing + +anything to it, they're +a very bad person. + +So fine. + +It's a legal optimization. + +Now. + +is it faster? + +How many people think that +returning zero is slower than + +pushing two things up? + +AUDIENCE: [LAUGHTER] + +AUDIENCE: Depends upon +how big zero is. + +PROFESSOR: That's true. + +So OK, so yes, obviously, +it's faster to just + +directly return zero. + +And finally, is this an +automatic optimization? + +How many people say yes? + +Cool. + +Nobody said yes. + +How many people say no? + +People who say yes, if you +could work for compiler + +companies, I would appreciate +that a lot. + +So unfortunately, the compiler +does not make-- + +cannot reason through how an +STL list works, and realize + +that what you're doing +is an no op. + +It turns out that for a related +set of questions, like + +have any of your mentors said +anything to-- so my mentor + +said this to me last year. + +And I was pretty interested +when I tried it out. + +Have you ever used a for loop to +set everything in an array + +to equals 0? + +Most people seem to +have done that. + +Who has used the memset or heard +of the memset set API + +call before? + +A good portion of the class. + +OK, so some people. + +So a little bit of +background then. + +Mem set instruction takes in an +array or a pointer rather, + +and a constant, and the +size of the array. + +And it sets that many elements +of the array to that constant. + +So it turns out that depending +on the machine that you're + +using, there is more efficient +and less efficient ways of + +setting all the elements +of an array to 0. + +And functions like mem set are +actually are several pages + +long of hand optimized assembly +to be optimal for + +your architecture. + +So it's always tempting to take +a for loop that iterates + +through an array, setting +everything to 0, and changing + +it to a single mem +set instruction. + +And it turns out that for both +gcc and icc, Intel C compiler, + +when you compile at sufficient +optimization level, the + +compiler actually does +this for you. + +It actually looks through +the arrays. + +It actually realizes that you're +setting all the members + +in the array to a constant, and +it does that optimization + +for you by replacing it +with a memset call. + +So just as a general question, +why could it be advantageous + +for you to write the four loop +as is, and have the compiler + +do the optimization for you? + +AUDIENCE: Because you later +might add code in the loop. + +PROFESSOR: True. + +Any other reasons? + +PROFESSOR: I didn't +hear question. + +PROFESSOR: You might want to +add code that changes the + +behavior inside the loop. + +AUDIENCE: It's much more +readable to have a for loop + +and you just read it, and I get +that's what he's doing. + +PROFESSOR: Yes, indeed. + +Looking over some of your code +submissions, it seems to be a + +non-trivial task of figuring out +the size of something when + +you call malloc or memset. + +And actually, it sometimes is +a non-trivial operation to + +figure out how big something +is in bytes, especially for + +structs and things like that. + +So it actually is easier to +let the compiler do the + +optimization for you, and you +don't make any embarrassing + +mistakes in the process. + +So next question. + +So here you have a +helper function. + +And in the after version, +seems to do the + +same thing, does it? + +So who thinks this is a +legal optimization? + +Half the class. + +Anyone think it's illegal? + +So yeah, it is legal. + +The only thing that I've done +is that I've copy pasted + +basically the function body +in the bottom example. + +And it's relatively easy to +prove that or infer that the + +two do the same thing. + +So is it faster? + +How many people say yes? + +How many people say no? + +One person said no. + +Why is it not faster? + +AUDIENCE: I mean, I've said +that it is the same speed, + +because so the only thing that +would make it slower would be + +the-- you need to actually +do like a compass switch. + +Because you need to call that +function every time. + +But I think it could provide +the concept for you-- like + +basically, it's a +static function. + +It would inline it even though +you don't have to declare it. + +PROFESSOR: OK. + +So if you recall the rules for +the question, so basically we + +want you to interpret the +code, as is, like a very + +literal interpretation as in-- + +the point was raised that for +this function call, what you + +actually want to do is assume +that the compiler is setting + +up a function called by putting +the arguments in the + +right register and jumping +to the address of + +that function above. + +So for the case of this-- for +the matter-- for the purpose + +of this question, yes, it's +much faster to just do a + +multiply compared to setting up +a call stack and tearing it + +down after the function +is done. + +Now the next question is is this +automatic, which was more + +or less answered. + +And that's yes. + +So at a sufficient optimization +level which is + +-03 or -02 with dash f inline +functions, the compiler will + +actually use a heuristic that it +has for determining whether + +or not a function is a good +candidate for inlining. + +And for good candidates, it'll +do the inlining for you. + +Now the specific +heuristics vary + +from compiler to compiler. + +But for this specific problem +that we gave you, it's a prime + +candidate for inlining, because +it's declared as + +static, which means it's +local to this C file. + +And it does a very simple +task, a one-liner, so it + +almost certainly will +be inline for you. + +Any questions? + +Cool. + +So this one. + +Question? + +AUDIENCE: I don't get it. + +Could you explain again? + +I know I've asked this +before, like what's + +static, the static function? + +And it's different +than in Java? + +PROFESSOR: OK. + +So the question was what's a +static function in C. And so + +in C, a static function means +when you declare a function as + +static, it means that the +function is local to the + +current file that you're work-- +the current module, the + +dot-o file, which is almost +always your dot-c file. + +So like the function only exists +within this dot-c file. + +A function in another +dot-c file + +cannot call this function. + +So it basically allows the +compiler to assume that + +there's no external effects on +this function that are not + +within this file. + +Remember the compiler compiles +object files one by one, and + +then the linker is the one that +brings it all together. + +AUDIENCE: So the important thing +is that it knows that it + +can just delete helper after +it's gotten rid of it. + +PROFESSOR: Right, right. + +That's another good point. + +So in this case, after inlining, +the compiler + +actually won't bother to put in +the function helper inside + +the actual object file. + +So you save on my code space. + +Because the compiler knows +that nowhere else this + +function can be called. + +AUDIENCE: What about +static in C++? + +PROFESSOR: Static in C++ when +used inside a class means that + +the function is a static +member function. + +So it's a function that's tied +to the class itself, rather + +than an object, and instance +of the class. + +AUDIENCE: Just like Java. + +PROFESSOR: Just like Java. + +More questions? + +Cool. + +So back to this code. + +First of all, is anyone not +familiar with the syntax or + +wants the syntax explained? + +OK, cool. + +So first question, +is it legal? + +How may people say yes? + +Half the class. + +How many people say no. + +Roughly half the class. + +Well, I and the people grading +the quiz will side with the + +people who say no, because down +here when you're doing-- + +this is the correct version +of the XOR swap. + +I'm not trying to trick +anyone there. + +But it turns out-- + +well, I'd rather not assume +that t, the arbitrary type + +name, has an operator XOR +defined for it that has all + +the properties that you need +in order for it to do this. + +Like the simplest example is +if I pass in a double, this + +would not work. + +Double does not have an operator +XOR defined for it. + +Some people look upset. + +AUDIENCE: [LAUGHTER] + +PROFESSOR: A list too +would not have an + +XOR defined for it. + +Anyone disagree with me? + +That's not a challenge. + +So yeah, some of these questions +require you to do a + +little bit of reasoning, like +reasonable reasoning, as far + +as what to assume for the +purposes of the question. + +So watch out for that. + +So in this case, it's not legal, +so you don't have to + +answer the next two questions. + +So OK. + +So let's fix this. + +And by fix it, I mean +not use templates. + +So now we're just operating +on ints. + +And ints do have the proper +operator XOR that has all the + +good properties that you want. + +Yes? + +AUDIENCE: What's the and +notation of the variable. + +PROFESSOR: It's a reference. + +So it's a reference to it. + +Because you need references, +because you actually want to + +swap the two items that +are being called in. + +Right? + +AUDIENCE: Can you use +like pointeres? + +PROFESSOR: Yes, so you can also +use a pointer for it. + +Pointers and references, C +will treat this use of + +references the same way as +if you use pointers. + +So references are +syntactic sugar. + +And what it basically allows you +to do is write code that + +looks like you're operating on +standard intervals, standard + +integers, but in fact that it's +a pointer to the value + +that the name of the variable +that's passed in here. + +Otherwise this code would be +riddled with a bunch of stars. + +Now is this legal? + +How many people say yes? + +Most of the class. + +How many people say no? + +One person. + +Yes? + +AUDIENCE: If A and B are +the same variable, + +you set it to zero. + +PROFESSOR: Yes, exactly. + +The XOR law has a nasty side +effect where you want to make + +sure that A and B are not +the same variable. + +Not they don't contain the +same-- they can contain the + +same value in different +variables, but they can't be + +the same variable or the +same register or + +the same memory location. + +Otherwise, when you do A equals +Ax or B, that's 0. + +And now both A and +B point to 0. + +And there's nothing you can do +to get your old value back. + +AUDIENCE: Can you check +for equivalence of + +recordkeeping in C++. + +PROFESSOR: Indeed, you can. + +If you take the address of the +reference, it gives you the + +address of the original value. + +So this would be the proper +way, I guess, of + +doing an XOR swap. + +So now that we've gotten over +all the trick questions, is + +this actually faster? + +How many people say yes? + +One, two, three, four. + +How many people say no? + +Cool. + +Most of the class. + +So this is another example +of a gray area question. + +So in this class, we primarily +talk about the cloud machines, + +as far as the performance +analysis that we've done. + +So on the cloud machines, and +this was mentioned in + +Charles's bit hacks lecture +which was, well, the second + +lecture in the course. + +This trick is not faster +on the cloud machines. + +Because what you end up doing +is you create a lot of + +dependencies between these +operands, so that the pipeline + +must execute these one +by one serially. + +So you introduce a lot +of delays by that. + +And plus now that we actually +want you to write a correct + +program, you have to +do this check, and + +that's an extra branch. + +And finally these XORs have to +be done by the ALU, and up to + +five execution ports. + +Only three of them are ALUs. + +The other two can do memory +operations just fine. + +So it turns out that for a +combination of these reasons, + +this version indeed with the +temporary register actually + +does run faster. + +Any questions? + +Yes. + +AUDIENCE: For branches, we +assume advanced features, like + +it will preload the exceptions +and only invalidates the thing + +when certain branches fail. + +PROFESSOR: Sure, you can assume +cool properties about + +the chip, such as speculative +execution, + +prefetching, and so on. + +But the problem is those tricks +are fine when you're + +doing things sparsely as in +you're sometimes doing work + +and other times not +doing work. + +But like speculative execution, +like when you + +execute both sides of a branch, +you're using more or + +less double your execution +or resources. + +And if you have all processors +running some intense piece of + +code that's doing swapping, +you don't have any extra + +resources to dedicate towards +running code that + +might not be useful. + +Any other questions? + +Cool. + +So finally, I got tired +of making slides. + +Well, actually that's +not true. + +It's more I'd rather concentrate +the slides on + +things that I think are more +useful than other things, as + +far as per preparation +for your quiz. + +All your time is valuable. + +And so there's other topics +that are fair game for the + +quiz, because they've been +mentioned in lectures up to + +this point. + +But I haven't prepared +any slides on them. + +And the fractal trees were +covered by the guest lecture + +by Bradley. + +And the slides are up. + +I suggest familiarizing yourself +with the basic + +workings of how the data +structure that + +he described works. + +And lock free data structures +were covered on your take home + +P set, and also in a lecture. + +So be prepared to +answer potential + +questions about that. + +And then finally the mechanism +behind the Cilk runtime, the + +work stealing scheduler, how +it's implemented on the Linux + +side, and also the basics of +what a Cilk hyperobject is, + +what a Cilk hyperobject +has to have. + +Advantages and disadvantages +of using them and so on. + +Yes. + +AUDIENCE: Are the grades +for the P-set out? + +PROFESSOR: No, they +are not out yet. + +AUDIENCE: Are there solutions +for the P-set? + +PROFESSOR: Not yet. + +But I believe we have something + +prepared for that, right? + +Somewhat? + +Yeah, it's somewhat prepared. + +If you have any questions about +like questions on the + +pset that you want answer to, +feel free to stop by office + +hours or email us and +we can help you. + +Yeah, apologies for not +getting that P set + +back to you in time. + +Any other questions relating +to the quiz. + +It's really all the material +I have as far as reviewing. + +Yes? + +AUDIENCE: Are you going to +put these slides up? + +AUDIENCE: Yeah, I'll +put these slides up + +right after the lecture. + +So as far as a general notes, +I guess you guys turned in + +your finals yesterday, and you +guys have a design report that + +you also turned in. + +Your POSSE members should have +contacted you by now, as far + +as scheduling a design +review session. + +Since this project is actually +due on next Thursday, it might + +be a good idea to get this done +by the end of the week. + +Otherwise, the design +review won't be + +a very useful process. + +AUDIENCE: There are a couple of +students without a mentor + +right now here. + +We are fixing that. + +PROFESSOR: Right. + +There's a couple of students +caught in limbo right now. + +Sorry about that. + +PROFESSOR: If you were-- +previously dropped on Stellar, + +send us an email. + +If you haven't been to drop +through this course, there are + +no longer drops allowed. + +Yeah, + +AUDIENCE: So it's your +responsibility. + +I'm going to put +on my mean hat. + +It's your responsibility to +schedule a meeting with your + +POSSE member, and make sure +that it happens by + +the end of the week. + +And if it doesn't look like +it's going to happen, or + +you're having difficulties +getting in touch with your + +mentor, or you don't have one +yet, please drop us an email + +or come by office hours and +make sure that we know. + +All right. + +That's it. \ No newline at end of file diff --git a/bEF_PpP6eCM.txt b/bEF_PpP6eCM.txt new file mode 100644 index 0000000000000000000000000000000000000000..9b43b437e9043e1c008d0786bb037c46faf337d5 --- /dev/null +++ b/bEF_PpP6eCM.txt @@ -0,0 +1,1835 @@ +align:start position:0% + +now + + align:start position:0% +now + + + align:start position:0% +now +given that you have a valuation model + + align:start position:0% +given that you have a valuation model + + + align:start position:0% +given that you have a valuation model +given that you have uncertainties + + align:start position:0% +given that you have uncertainties + + + align:start position:0% +given that you have uncertainties +you can see what the outcome the + + align:start position:0% +you can see what the outcome the + + + align:start position:0% +you can see what the outcome the +performance of your system is + + align:start position:0% +performance of your system is + + + align:start position:0% +performance of your system is +when there's no flexibility simply + + align:start position:0% +when there's no flexibility simply + + + align:start position:0% +when there's no flexibility simply +saying okay if we build this plant + + align:start position:0% +saying okay if we build this plant + + + align:start position:0% +saying okay if we build this plant +and + + align:start position:0% +and + + + align:start position:0% +and +then see what the revenues are + + align:start position:0% +then see what the revenues are + + + align:start position:0% +then see what the revenues are +we can think about well our production + + align:start position:0% +we can think about well our production + + + align:start position:0% +we can think about well our production +may go up and down because of mechanical + + align:start position:0% +may go up and down because of mechanical + + + align:start position:0% +may go up and down because of mechanical +problems or whatever the demand may go + + align:start position:0% +problems or whatever the demand may go + + + align:start position:0% +problems or whatever the demand may go +up and down + + align:start position:0% +up and down + + + align:start position:0% +up and down +depending upon competition or whatever + + align:start position:0% +depending upon competition or whatever + + + align:start position:0% +depending upon competition or whatever +and all together we may have the + + align:start position:0% +and all together we may have the + + + align:start position:0% +and all together we may have the +following results in terms of benefits + + align:start position:0% +following results in terms of benefits + + + align:start position:0% +following results in terms of benefits +and costs + + align:start position:0% +and costs + + + align:start position:0% +and costs +so + + align:start position:0% +so + + + align:start position:0% +so +you will to do this you generate a + + align:start position:0% +you will to do this you generate a + + + align:start position:0% +you will to do this you generate a +dynamic scenario and apply it to the + + align:start position:0% +dynamic scenario and apply it to the + + + align:start position:0% +dynamic scenario and apply it to the +model + + align:start position:0% +model + + + align:start position:0% +model +period by period that is the demand + + align:start position:0% +period by period that is the demand + + + align:start position:0% +period by period that is the demand +starts at one level goes up goes up goes + + align:start position:0% +starts at one level goes up goes up goes + + + align:start position:0% +starts at one level goes up goes up goes +down up down whatever and you do that + + align:start position:0% +down up down whatever and you do that + + + align:start position:0% +down up down whatever and you do that +for all the different demand + + align:start position:0% +for all the different demand + + + align:start position:0% +for all the different demand +possibilities that you simulate and then + + align:start position:0% +possibilities that you simulate and then + + + align:start position:0% +possibilities that you simulate and then +you can think about that would also + + align:start position:0% +you can think about that would also + + + align:start position:0% +you can think about that would also +happen in terms of production + + align:start position:0% +happen in terms of production + + + align:start position:0% +happen in terms of production +possibilities + + align:start position:0% +possibilities + + + align:start position:0% +possibilities +and + + align:start position:0% +and + + + align:start position:0% +and +for each of those scenarios + + align:start position:0% +for each of those scenarios + + + align:start position:0% +for each of those scenarios +combination of the variables you'll get + + align:start position:0% +combination of the variables you'll get + + + align:start position:0% +combination of the variables you'll get +a performance measure for example the + + align:start position:0% +a performance measure for example the + + + align:start position:0% +a performance measure for example the +net present value for that + + align:start position:0% +net present value for that + + + align:start position:0% +net present value for that +you go through the simulation we'll go + + align:start position:0% +you go through the simulation we'll go + + + align:start position:0% +you go through the simulation we'll go +through this process + + align:start position:0% +through this process + + + align:start position:0% +through this process +2 000 examples is a standard number so a + + align:start position:0% +2 000 examples is a standard number so a + + + align:start position:0% +2 000 examples is a standard number so a +lot of people use there's a way of + + align:start position:0% +lot of people use there's a way of + + + align:start position:0% +lot of people use there's a way of +saying of determining whether you think + + align:start position:0% +saying of determining whether you think + + + align:start position:0% +saying of determining whether you think +2 000 is better than 1 000 or better + + align:start position:0% +2 000 is better than 1 000 or better + + + align:start position:0% +2 000 is better than 1 000 or better +than 10 000 or what's the right balance + + align:start position:0% +than 10 000 or what's the right balance + + + align:start position:0% +than 10 000 or what's the right balance +we won't get into that for the moment + + align:start position:0% +we won't get into that for the moment + + + align:start position:0% +we won't get into that for the moment +but what i'm saying is + + align:start position:0% +but what i'm saying is + + + align:start position:0% +but what i'm saying is +that doing 2000 is a + + align:start position:0% +that doing 2000 is a + + + align:start position:0% +that doing 2000 is a +reasonable first order approximation at + + align:start position:0% +reasonable first order approximation at + + + align:start position:0% +reasonable first order approximation at +least + + align:start position:0% +least + + + align:start position:0% +least +so that you have 2 000 + + align:start position:0% +so that you have 2 000 + + + align:start position:0% +so that you have 2 000 +measures of performance such as the + + align:start position:0% +measures of performance such as the + + + align:start position:0% +measures of performance such as the +present value + + align:start position:0% +present value + + + align:start position:0% +present value +and you can calculate the averages + + align:start position:0% +and you can calculate the averages + + + align:start position:0% +and you can calculate the averages +the in particular the e and b the + + align:start position:0% +the in particular the e and b the + + + align:start position:0% +the in particular the e and b the +expected + + align:start position:0% +expected + + + align:start position:0% +expected +the average and you could then think + + align:start position:0% +the average and you could then think + + + align:start position:0% +the average and you could then think +about what the extremes are and so on + + align:start position:0% +about what the extremes are and so on + + + align:start position:0% +about what the extremes are and so on +you can plot the distribution so that's + + align:start position:0% +you can plot the distribution so that's + + + align:start position:0% +you can plot the distribution so that's +the + + align:start position:0% +the + + + align:start position:0% +the +um + + align:start position:0% +um + + + align:start position:0% +um +the basic result of a simulation + + align:start position:0% +the basic result of a simulation + + + align:start position:0% +the basic result of a simulation +now + + align:start position:0% +now + + + align:start position:0% +now +it's important to recognize + + align:start position:0% +it's important to recognize + + + align:start position:0% +it's important to recognize +the nature of the product from the + + align:start position:0% +the nature of the product from the + + + align:start position:0% +the nature of the product from the +simulation analysis + + align:start position:0% +simulation analysis + + + align:start position:0% +simulation analysis +a traditional discount cash flow + + align:start position:0% +a traditional discount cash flow + + + align:start position:0% +a traditional discount cash flow +spreadsheet analysis + + align:start position:0% +spreadsheet analysis + + + align:start position:0% +spreadsheet analysis +for the use for net present value is + + align:start position:0% +for the use for net present value is + + + align:start position:0% +for the use for net present value is +numbers in and numbers out + + align:start position:0% +numbers in and numbers out + + + align:start position:0% +numbers in and numbers out +you use your best estimate for + + align:start position:0% +you use your best estimate for + + + align:start position:0% +you use your best estimate for +investment cost production sales etc + + align:start position:0% +investment cost production sales etc + + + align:start position:0% +investment cost production sales etc +you put the numbers in you run the + + align:start position:0% +you put the numbers in you run the + + + align:start position:0% +you put the numbers in you run the +machine you get a number the net present + + align:start position:0% +machine you get a number the net present + + + align:start position:0% +machine you get a number the net present +value is such they're turning on + + align:start position:0% +value is such they're turning on + + + align:start position:0% +value is such they're turning on +investment it's such + + align:start position:0% +investment it's such + + + align:start position:0% +investment it's such +in a simulation and uncertainty analysis + + align:start position:0% +in a simulation and uncertainty analysis + + + align:start position:0% +in a simulation and uncertainty analysis +you don't put a number in you put in a + + align:start position:0% +you don't put a number in you put in a + + + align:start position:0% +you don't put a number in you put in a +shape and a distribution + + align:start position:0% +shape and a distribution + + + align:start position:0% +shape and a distribution +and you get a distribution out + + align:start position:0% +and you get a distribution out + + + align:start position:0% +and you get a distribution out +and + + align:start position:0% +and + + + align:start position:0% +and +the target curve is a generic name to + + align:start position:0% +the target curve is a generic name to + + + align:start position:0% +the target curve is a generic name to +describe what that distribution is + + align:start position:0% +describe what that distribution is + + + align:start position:0% +describe what that distribution is +typically it's either of two shapes + + align:start position:0% +typically it's either of two shapes + + + align:start position:0% +typically it's either of two shapes +one is the one i personally prefer but + + align:start position:0% +one is the one i personally prefer but + + + align:start position:0% +one is the one i personally prefer but +it's a matter of choice + + align:start position:0% +it's a matter of choice + + + align:start position:0% +it's a matter of choice +uh is a cumulative distribution + + align:start position:0% +uh is a cumulative distribution + + + align:start position:0% +uh is a cumulative distribution +it shows from + + align:start position:0% +it shows from + + + align:start position:0% +it shows from +there may be some chances things are + + align:start position:0% +there may be some chances things are + + + align:start position:0% +there may be some chances things are +really bad + + align:start position:0% +really bad + + + align:start position:0% +really bad +more chances of things are better and + + align:start position:0% +more chances of things are better and + + + align:start position:0% +more chances of things are better and +etc it goes on up a cumulative + + align:start position:0% +etc it goes on up a cumulative + + + align:start position:0% +etc it goes on up a cumulative +distribution to + + align:start position:0% +distribution to + + + align:start position:0% +distribution to +uh there's nothing that's not likely to + + align:start position:0% +uh there's nothing that's not likely to + + + align:start position:0% +uh there's nothing that's not likely to +be any better than a particular maxim + + align:start position:0% +be any better than a particular maxim + + + align:start position:0% +be any better than a particular maxim +and but you could also show it as a + + align:start position:0% +and but you could also show it as a + + + align:start position:0% +and but you could also show it as a +distribution sort of think of it as a + + align:start position:0% +distribution sort of think of it as a + + + align:start position:0% +distribution sort of think of it as a +normal shape or something + + align:start position:0% +normal shape or something + + + align:start position:0% +normal shape or something +it could be or it could be bimodal but + + align:start position:0% +it could be or it could be bimodal but + + + align:start position:0% +it could be or it could be bimodal but +the shape of a frequency or the + + align:start position:0% +the shape of a frequency or the + + + align:start position:0% +the shape of a frequency or the +cumulative + + align:start position:0% + + + + align:start position:0% + +um how do you create the target curve or + + align:start position:0% +um how do you create the target curve or + + + align:start position:0% +um how do you create the target curve or +how does the process create the target + + align:start position:0% +how does the process create the target + + + align:start position:0% +how does the process create the target +first + + align:start position:0% + + + + align:start position:0% + +so the simulation produces many trials + + align:start position:0% +so the simulation produces many trials + + + align:start position:0% +so the simulation produces many trials +now the probability of each scenario + + align:start position:0% +now the probability of each scenario + + + align:start position:0% +now the probability of each scenario +when you've done the simulation + + align:start position:0% +when you've done the simulation + + + align:start position:0% +when you've done the simulation +correctly the way it should be done + + align:start position:0% +correctly the way it should be done + + + align:start position:0% +correctly the way it should be done +is that each one is equally probable why + + align:start position:0% +is that each one is equally probable why + + + align:start position:0% +is that each one is equally probable why +because you sampled from the underlying + + align:start position:0% +because you sampled from the underlying + + + align:start position:0% +because you sampled from the underlying +distribution according to their + + align:start position:0% +distribution according to their + + + align:start position:0% +distribution according to their +probability + + align:start position:0% +probability + + + align:start position:0% +probability +if + + align:start position:0% +if + + + align:start position:0% +if +the + + align:start position:0% +the + + + align:start position:0% +the +high value was four times more probable + + align:start position:0% +high value was four times more probable + + + align:start position:0% +high value was four times more probable +than the low value you sampled the high + + align:start position:0% +than the low value you sampled the high + + + align:start position:0% +than the low value you sampled the high +value four times and the low value one + + align:start position:0% +value four times and the low value one + + + align:start position:0% +value four times and the low value one +time + + align:start position:0% +time + + + align:start position:0% +time +so that + + align:start position:0% +so that + + + align:start position:0% +so that +you've sampled it from the uh + + align:start position:0% +you've sampled it from the uh + + + align:start position:0% +you've sampled it from the uh +according to the distribution so the + + align:start position:0% +according to the distribution so the + + + align:start position:0% +according to the distribution so the +consequence is that each of your 2000 or + + align:start position:0% +consequence is that each of your 2000 or + + + align:start position:0% +consequence is that each of your 2000 or +however many + + align:start position:0% +however many + + + align:start position:0% +however many +simulations have the same probability + + align:start position:0% +simulations have the same probability + + + align:start position:0% +simulations have the same probability +given that giving you 2000 results the + + align:start position:0% +given that giving you 2000 results the + + + align:start position:0% +given that giving you 2000 results the +way that + + align:start position:0% +way that + + + align:start position:0% +way that +it proceeded mechanically is to bend the + + align:start position:0% +it proceeded mechanically is to bend the + + + align:start position:0% +it proceeded mechanically is to bend the +results but as you look at outcome + + align:start position:0% +results but as you look at outcome + + + align:start position:0% +results but as you look at outcome +ranges the first one percent two percent + + align:start position:0% +ranges the first one percent two percent + + + align:start position:0% +ranges the first one percent two percent +three you know maybe a hundred times 100 + + align:start position:0% +three you know maybe a hundred times 100 + + + align:start position:0% +three you know maybe a hundred times 100 +bins + + align:start position:0% +bins + + + align:start position:0% +bins +and + + align:start position:0% +and + + + align:start position:0% +and +that there so the number of samples in + + align:start position:0% +that there so the number of samples in + + + align:start position:0% +that there so the number of samples in +each bin is that frequency and that + + align:start position:0% +each bin is that frequency and that + + + align:start position:0% +each bin is that frequency and that +creates a histogram if you want or if + + align:start position:0% +creates a histogram if you want or if + + + align:start position:0% +creates a histogram if you want or if +it's if you have enough ones + + align:start position:0% +it's if you have enough ones + + + align:start position:0% +it's if you have enough ones +it is no longer a bar chart but it's a + + align:start position:0% +it is no longer a bar chart but it's a + + + align:start position:0% +it is no longer a bar chart but it's a +and that can easily be + + align:start position:0% +and that can easily be + + + align:start position:0% +and that can easily be +calculated into a cumulative + + align:start position:0% +calculated into a cumulative + + + align:start position:0% +calculated into a cumulative +distribution so this entire process is + + align:start position:0% +distribution so this entire process is + + + align:start position:0% +distribution so this entire process is +easily automated and the garage case + + align:start position:0% +easily automated and the garage case + + + align:start position:0% +easily automated and the garage case +template which is a very + + align:start position:0% +template which is a very + + + align:start position:0% +template which is a very +trivial um spreadsheet but it does that + + align:start position:0% +trivial um spreadsheet but it does that + + + align:start position:0% +trivial um spreadsheet but it does that +for you so if you wanted to do it + + align:start position:0% +for you so if you wanted to do it + + + align:start position:0% +for you so if you wanted to do it +yourself you can do it but it's not + + align:start position:0% +yourself you can do it but it's not + + + align:start position:0% +yourself you can do it but it's not +particularly unnecessary it's all done + + align:start position:0% +particularly unnecessary it's all done + + + align:start position:0% +particularly unnecessary it's all done +for you for your projects if you're + + align:start position:0% +for you for your projects if you're + + + align:start position:0% +for you for your projects if you're +using it or + + align:start position:0% +using it or + + + align:start position:0% +using it or +after class or + + align:start position:0% +after class or + + + align:start position:0% +after class or +later times + + align:start position:0% + + + + align:start position:0% + +so here is an example for of it that + + align:start position:0% +so here is an example for of it that + + + align:start position:0% +so here is an example for of it that +there's a + + align:start position:0% +there's a + + + align:start position:0% +there's a +all these uh individual bins have been + + align:start position:0% +all these uh individual bins have been + + + align:start position:0% +all these uh individual bins have been +put together and here is the + + align:start position:0% +put together and here is the + + + align:start position:0% +put together and here is the +on their probability of each and here is + + align:start position:0% +on their probability of each and here is + + + align:start position:0% +on their probability of each and here is +the cumulative distribution the target + + align:start position:0% +the cumulative distribution the target + + + align:start position:0% +the cumulative distribution the target +curve a target curve + + align:start position:0% +curve a target curve + + + align:start position:0% +curve a target curve +um by the way just to make it clear here + + align:start position:0% +um by the way just to make it clear here + + + align:start position:0% +um by the way just to make it clear here +so this is the + + align:start position:0% +so this is the + + + align:start position:0% +so this is the +um + + align:start position:0% +um + + + align:start position:0% +um +uh + + align:start position:0% +uh + + + align:start position:0% +uh +going from 0 to a hundred percent so + + align:start position:0% +going from 0 to a hundred percent so + + + align:start position:0% +going from 0 to a hundred percent so +there's nothing worse than this + + align:start position:0% +there's nothing worse than this + + + align:start position:0% +there's nothing worse than this +particular number in your distribution + + align:start position:0% +particular number in your distribution + + + align:start position:0% +particular number in your distribution +that's the lowest one this is the + + align:start position:0% +that's the lowest one this is the + + + align:start position:0% +that's the lowest one this is the +highest 100 + + align:start position:0% +highest 100 + + + align:start position:0% +highest 100 +and this one for example here is + + align:start position:0% +and this one for example here is + + + align:start position:0% +and this one for example here is +that at the zero level for some reason + + align:start position:0% +that at the zero level for some reason + + + align:start position:0% +that at the zero level for some reason +uh it's 50 + + align:start position:0% +uh it's 50 + + + align:start position:0% +uh it's 50 +but it doesn't have to be that way but + + align:start position:0% +but it doesn't have to be that way but + + + align:start position:0% +but it doesn't have to be that way but +uh it is in this in this particular case + + align:start position:0% +uh it is in this in this particular case + + + align:start position:0% +uh it is in this in this particular case +so this is an example of a cumulative + + align:start position:0% +so this is an example of a cumulative + + + align:start position:0% +so this is an example of a cumulative +distribution + + align:start position:0% + + + + align:start position:0% + +now the interesting aspect is how do you + + align:start position:0% +now the interesting aspect is how do you + + + align:start position:0% +now the interesting aspect is how do you +look at flexibility + + align:start position:0% +look at flexibility + + + align:start position:0% +look at flexibility +so the first question is of course well + + align:start position:0% +so the first question is of course well + + + align:start position:0% +so the first question is of course well +what flexibility what are we talking + + align:start position:0% +what flexibility what are we talking + + + align:start position:0% +what flexibility what are we talking +about + + align:start position:0% +about + + + align:start position:0% +about +and the answer to that in general is the + + align:start position:0% +and the answer to that in general is the + + + align:start position:0% +and the answer to that in general is the +flexibility + + align:start position:0% +flexibility + + + align:start position:0% +flexibility +that is + + align:start position:0% +that is + + + align:start position:0% +that is +has the most impact regarding the + + align:start position:0% +has the most impact regarding the + + + align:start position:0% +has the most impact regarding the +uncertainties and how if you had a + + align:start position:0% +uncertainties and how if you had a + + + align:start position:0% +uncertainties and how if you had a +really bad case uh what would you do + + align:start position:0% +really bad case uh what would you do + + + align:start position:0% +really bad case uh what would you do +about it and what kind of flexibility + + align:start position:0% +about it and what kind of flexibility + + + align:start position:0% +about it and what kind of flexibility +would help you in the would be most + + align:start position:0% +would help you in the would be most + + + align:start position:0% +would help you in the would be most +impactful + + align:start position:0% +impactful + + + align:start position:0% +impactful +in the case of the garage case + + align:start position:0% +in the case of the garage case + + + align:start position:0% +in the case of the garage case +the uncertainty is in the demand so what + + align:start position:0% +the uncertainty is in the demand so what + + + align:start position:0% +the uncertainty is in the demand so what +kind of flexibility is the capacity meat + + align:start position:0% +kind of flexibility is the capacity meat + + + align:start position:0% +kind of flexibility is the capacity meat +to demand so it's the number of levels + + align:start position:0% +to demand so it's the number of levels + + + align:start position:0% +to demand so it's the number of levels +in the garage + + align:start position:0% +in the garage + + + align:start position:0% +in the garage +in a particular case you'd have to think + + align:start position:0% +in a particular case you'd have to think + + + align:start position:0% +in a particular case you'd have to think +about that for your problem of what kind + + align:start position:0% +about that for your problem of what kind + + + align:start position:0% +about that for your problem of what kind +of flexibility might be most impactful + + align:start position:0% +of flexibility might be most impactful + + + align:start position:0% +of flexibility might be most impactful +and for those of you who are doing + + align:start position:0% +and for those of you who are doing + + + align:start position:0% +and for those of you who are doing +projects we'll look at that uh in detail + + align:start position:0% +projects we'll look at that uh in detail + + + align:start position:0% +projects we'll look at that uh in detail +that is one of the questions that you'll + + align:start position:0% +that is one of the questions that you'll + + + align:start position:0% +that is one of the questions that you'll +want to wrestle with + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +then the thing is okay i have this + + align:start position:0% +then the thing is okay i have this + + + align:start position:0% +then the thing is okay i have this +flexibility for example of building an + + align:start position:0% +flexibility for example of building an + + + align:start position:0% +flexibility for example of building an +extra floor on my garage + + align:start position:0% +extra floor on my garage + + + align:start position:0% +extra floor on my garage +when should i exercise it should i do it + + align:start position:0% +when should i exercise it should i do it + + + align:start position:0% +when should i exercise it should i do it +right away should i do an anticipation + + align:start position:0% +right away should i do an anticipation + + + align:start position:0% +right away should i do an anticipation +of future demand should i wait until + + align:start position:0% +of future demand should i wait until + + + align:start position:0% +of future demand should i wait until +demand is there + + align:start position:0% +demand is there + + + align:start position:0% +demand is there +um + + align:start position:0% +um + + + align:start position:0% +um +in simulation we can't do this we don't + + align:start position:0% +in simulation we can't do this we don't + + + align:start position:0% +in simulation we can't do this we don't +have a way of calculating when's the + + align:start position:0% +have a way of calculating when's the + + + align:start position:0% +have a way of calculating when's the +optimal time + + align:start position:0% +optimal time + + + align:start position:0% +optimal time +there are some methods for dealing with + + align:start position:0% +there are some methods for dealing with + + + align:start position:0% +there are some methods for dealing with +that such as dynamic programming + + align:start position:0% +that such as dynamic programming + + + align:start position:0% +that such as dynamic programming +but it implies dynamic programming + + align:start position:0% +but it implies dynamic programming + + + align:start position:0% +but it implies dynamic programming +implies there's nothing you can do about + + align:start position:0% +implies there's nothing you can do about + + + align:start position:0% +implies there's nothing you can do about +it to affect future aspects this is the + + align:start position:0% +it to affect future aspects this is the + + + align:start position:0% +it to affect future aspects this is the +so-called path independence function and + + align:start position:0% +so-called path independence function and + + + align:start position:0% +so-called path independence function and +the whole point of having flexibility is + + align:start position:0% +the whole point of having flexibility is + + + align:start position:0% +the whole point of having flexibility is +precisely that you can do things so that + + align:start position:0% +precisely that you can do things so that + + + align:start position:0% +precisely that you can do things so that +um + + align:start position:0% +um + + + align:start position:0% +um +that + + align:start position:0% +that + + + align:start position:0% +that +powerful method + + align:start position:0% +powerful method + + + align:start position:0% +powerful method +does not work for for us so + + align:start position:0% +does not work for for us so + + + align:start position:0% +does not work for for us so +and there's so many paths i mean if we + + align:start position:0% +and there's so many paths i mean if we + + + align:start position:0% +and there's so many paths i mean if we +think about 2 000 samples of what may + + align:start position:0% +think about 2 000 samples of what may + + + align:start position:0% +think about 2 000 samples of what may +happen that's only 2 000 samples of what + + align:start position:0% +happen that's only 2 000 samples of what + + + align:start position:0% +happen that's only 2 000 samples of what +may be a million possibility of past as + + align:start position:0% +may be a million possibility of past as + + + align:start position:0% +may be a million possibility of past as +a combination of the different + + align:start position:0% +a combination of the different + + + align:start position:0% +a combination of the different +probabilities at different times uh + + align:start position:0% +probabilities at different times uh + + + align:start position:0% +probabilities at different times uh +of prices and quantities and so forth + + align:start position:0% +of prices and quantities and so forth + + + align:start position:0% +of prices and quantities and so forth +it's much too large to be searched + + align:start position:0% +it's much too large to be searched + + + align:start position:0% +it's much too large to be searched +so the procedure is to define + + align:start position:0% +so the procedure is to define + + + align:start position:0% +so the procedure is to define +what we know as decision rules + + align:start position:0% + + + + align:start position:0% + +you \ No newline at end of file diff --git a/d4skxu7MpFI.txt b/d4skxu7MpFI.txt new file mode 100644 index 0000000000000000000000000000000000000000..3bbd9d9d7e7db240afc743cde5fa149bc15ec7fc --- /dev/null +++ b/d4skxu7MpFI.txt @@ -0,0 +1,1971 @@ +align:start position:0% + +we were faced last time with the + + align:start position:0% +we were faced last time with the + + + align:start position:0% +we were faced last time with the +question of interpretation of the + + align:start position:0% +question of interpretation of the + + + align:start position:0% +question of interpretation of the +shrenger wavefunction and so to recap or + + align:start position:0% +shrenger wavefunction and so to recap or + + + align:start position:0% +shrenger wavefunction and so to recap or +the main ideas that were looking at we + + align:start position:0% +the main ideas that were looking at we + + + align:start position:0% +the main ideas that were looking at we +derived the Schrodinger equation + + align:start position:0% +derived the Schrodinger equation + + + align:start position:0% +derived the Schrodinger equation +basically derived it from simple ideas + + align:start position:0% +basically derived it from simple ideas + + + align:start position:0% +basically derived it from simple ideas +having operators energy operator + + align:start position:0% +having operators energy operator + + + align:start position:0% +having operators energy operator +momentum operator and exploring how the + + align:start position:0% +momentum operator and exploring how the + + + align:start position:0% +momentum operator and exploring how the +de Broglie wavelength associated to a + + align:start position:0% +de Broglie wavelength associated to a + + + align:start position:0% +de Broglie wavelength associated to a +particle would be a wave that would + + align:start position:0% +particle would be a wave that would + + + align:start position:0% +particle would be a wave that would +solve the equation and the equation was + + align:start position:0% +solve the equation and the equation was + + + align:start position:0% +solve the equation and the equation was +the Schrodinger equation a free shown in + + align:start position:0% +the Schrodinger equation a free shown in + + + align:start position:0% +the Schrodinger equation a free shown in +the equation and then we added a + + align:start position:0% +the equation and then we added a + + + align:start position:0% +the equation and then we added a +potential to make it interacting and + + align:start position:0% +potential to make it interacting and + + + align:start position:0% +potential to make it interacting and +that way we motivated the Schrodinger + + align:start position:0% +that way we motivated the Schrodinger + + + align:start position:0% +that way we motivated the Schrodinger +equation and took this form side effects + + align:start position:0% +equation and took this form side effects + + + align:start position:0% +equation and took this form side effects +on T and this is the dynamical equation + + align:start position:0% +on T and this is the dynamical equation + + + align:start position:0% +on T and this is the dynamical equation +that governs the wave function but the + + align:start position:0% +that governs the wave function but the + + + align:start position:0% +that governs the wave function but the +interpretation that we had for the wave + + align:start position:0% +interpretation that we had for the wave + + + align:start position:0% +interpretation that we had for the wave +function we discuss what Bourne said was + + align:start position:0% +function we discuss what Bourne said was + + + align:start position:0% +function we discuss what Bourne said was +that it's related to probabilities and + + align:start position:0% +that it's related to probabilities and + + + align:start position:0% +that it's related to probabilities and +size squared multiplied by a little DX + + align:start position:0% +size squared multiplied by a little DX + + + align:start position:0% +size squared multiplied by a little DX +would give you the probability to find + + align:start position:0% +would give you the probability to find + + + align:start position:0% +would give you the probability to find +the particle in that little DX at some + + align:start position:0% +the particle in that little DX at some + + + align:start position:0% +the particle in that little DX at some +particular time so sine of X and T + + align:start position:0% +particular time so sine of X and T + + + align:start position:0% +particular time so sine of X and T +squared DX + + align:start position:0% +squared DX + + + align:start position:0% +squared DX +would be the probability to find the + + align:start position:0% +would be the probability to find the + + + align:start position:0% +would be the probability to find the +particle at that interval DX around X + + align:start position:0% +particle at that interval DX around X + + + align:start position:0% +particle at that interval DX around X +and if you're describing the physics of + + align:start position:0% +and if you're describing the physics of + + + align:start position:0% +and if you're describing the physics of +your Schrodinger equation is that the + + align:start position:0% +your Schrodinger equation is that the + + + align:start position:0% +your Schrodinger equation is that the +single particle which is the case here + + align:start position:0% +single particle which is the case here + + + align:start position:0% +single particle which is the case here +one coordinate the coordinate of the + + align:start position:0% +one coordinate the coordinate of the + + + align:start position:0% +one coordinate the coordinate of the +particle this integral if you integrate + + align:start position:0% +particle this integral if you integrate + + + align:start position:0% +particle this integral if you integrate +this all over us + + align:start position:0% +this all over us + + + align:start position:0% +this all over us +must be one for the probability to make + + align:start position:0% +must be one for the probability to make + + + align:start position:0% +must be one for the probability to make +sense so the total probability of + + align:start position:0% +sense so the total probability of + + + align:start position:0% +sense so the total probability of +finding the particle must be 1 must be + + align:start position:0% +finding the particle must be 1 must be + + + align:start position:0% +finding the particle must be 1 must be +somewhere if it's in one part or another + + align:start position:0% +somewhere if it's in one part or another + + + align:start position:0% +somewhere if it's in one part or another +part or another part is probabilities + + align:start position:0% +part or another part is probabilities + + + align:start position:0% +part or another part is probabilities +for this to be a probability + + align:start position:0% +for this to be a probability + + + align:start position:0% +for this to be a probability +distribution has to be well normalized + + align:start position:0% +distribution has to be well normalized + + + align:start position:0% +distribution has to be well normalized +which means 1 and we said that this + + align:start position:0% +which means 1 and we said that this + + + align:start position:0% +which means 1 and we said that this +equation was interesting but somewhat + + align:start position:0% +equation was interesting but somewhat + + + align:start position:0% +equation was interesting but somewhat +worrisome because if the normalization + + align:start position:0% +worrisome because if the normalization + + + align:start position:0% +worrisome because if the normalization +of the wave function satisfies if this + + align:start position:0% +of the wave function satisfies if this + + + align:start position:0% +of the wave function satisfies if this +holds for a T equal T naught then the + + align:start position:0% +holds for a T equal T naught then the + + + align:start position:0% +holds for a T equal T naught then the +Schrodinger equation if you know the + + align:start position:0% +Schrodinger equation if you know the + + + align:start position:0% +Schrodinger equation if you know the +wave function all over space for T equal + + align:start position:0% +wave function all over space for T equal + + + align:start position:0% +wave function all over space for T equal +to naught which is what you would need + + align:start position:0% +to naught which is what you would need + + + align:start position:0% +to naught which is what you would need +to know in order to check that this is + + align:start position:0% +to know in order to check that this is + + + align:start position:0% +to know in order to check that this is +working at time equal T naught you take + + align:start position:0% +working at time equal T naught you take + + + align:start position:0% +working at time equal T naught you take +the sy of X and T naught integrate it + + align:start position:0% +the sy of X and T naught integrate it + + + align:start position:0% +the sy of X and T naught integrate it +but if you know sy of X and T naught for + + align:start position:0% +but if you know sy of X and T naught for + + + align:start position:0% +but if you know sy of X and T naught for +all X then the Schrodinger equation + + align:start position:0% +all X then the Schrodinger equation + + + align:start position:0% +all X then the Schrodinger equation +tells you what the wave function is at a + + align:start position:0% +tells you what the wave function is at a + + + align:start position:0% +tells you what the wave function is at a +later time because it gives you the time + + align:start position:0% +later time because it gives you the time + + + align:start position:0% +later time because it gives you the time +derivative of the wave function in terms + + align:start position:0% +derivative of the wave function in terms + + + align:start position:0% +derivative of the wave function in terms +of beta about the wave function all over + + align:start position:0% +of beta about the wave function all over + + + align:start position:0% +of beta about the wave function all over +space so automatically the Schrodinger + + align:start position:0% +space so automatically the Schrodinger + + + align:start position:0% +space so automatically the Schrodinger +equation must make it true that this + + align:start position:0% +equation must make it true that this + + + align:start position:0% +equation must make it true that this +will hold at later times you cannot + + align:start position:0% +will hold at later times you cannot + + + align:start position:0% +will hold at later times you cannot +force the wave function to satisfy this + + align:start position:0% +force the wave function to satisfy this + + + align:start position:0% +force the wave function to satisfy this +at all times you can force it maybe to + + align:start position:0% +at all times you can force it maybe to + + + align:start position:0% +at all times you can force it maybe to +satisfy it at one time but once it + + align:start position:0% +satisfy it at one time but once it + + + align:start position:0% +satisfy it at one time but once it +satisfies it at this time then it will + + align:start position:0% +satisfies it at this time then it will + + + align:start position:0% +satisfies it at this time then it will +evolve and it better be that at every + + align:start position:0% +evolve and it better be that at every + + + align:start position:0% +evolve and it better be that at every +time later it still satisfies this + + align:start position:0% +time later it still satisfies this + + + align:start position:0% +time later it still satisfies this +equation so this is a very + + align:start position:0% +equation so this is a very + + + align:start position:0% +equation so this is a very +important constraint so we'll basically + + align:start position:0% +important constraint so we'll basically + + + align:start position:0% +important constraint so we'll basically +develop this throughout the lecture + + align:start position:0% +develop this throughout the lecture + + + align:start position:0% +develop this throughout the lecture +today we're going to make a big point of + + align:start position:0% +today we're going to make a big point of + + + align:start position:0% +today we're going to make a big point of +this trying to explain why the + + align:start position:0% +this trying to explain why the + + + align:start position:0% +this trying to explain why the +conditions that we're going to impose on + + align:start position:0% +conditions that we're going to impose on + + + align:start position:0% +conditions that we're going to impose on +the wavefunction are necessary what it + + align:start position:0% +the wavefunction are necessary what it + + + align:start position:0% +the wavefunction are necessary what it +teaches you about the Hamiltonian will + + align:start position:0% +teaches you about the Hamiltonian will + + + align:start position:0% +teaches you about the Hamiltonian will +teach you that it's a hermitian operator + + align:start position:0% +teach you that it's a hermitian operator + + + align:start position:0% +teach you that it's a hermitian operator +what do you learn about probability you + + align:start position:0% +what do you learn about probability you + + + align:start position:0% +what do you learn about probability you +will learn that there's a probability + + align:start position:0% +will learn that there's a probability + + + align:start position:0% +will learn that there's a probability +current and all kinds of things is will + + align:start position:0% +current and all kinds of things is will + + + align:start position:0% +current and all kinds of things is will +come out of taking seriously the + + align:start position:0% +come out of taking seriously the + + + align:start position:0% +come out of taking seriously the +interpretation of it as probability the + + align:start position:0% +interpretation of it as probability the + + + align:start position:0% +interpretation of it as probability the +main point being that we can be sure it + + align:start position:0% +main point being that we can be sure it + + + align:start position:0% +main point being that we can be sure it +behaves as a probability at one time but + + align:start position:0% +behaves as a probability at one time but + + + align:start position:0% +behaves as a probability at one time but +then for later times to behave as a + + align:start position:0% +then for later times to behave as a + + + align:start position:0% +then for later times to behave as a +probability the Schrodinger equation + + align:start position:0% +probability the Schrodinger equation + + + align:start position:0% +probability the Schrodinger equation +must help must somehow be part of the + + align:start position:0% +must help must somehow be part of the + + + align:start position:0% +must help must somehow be part of the +reason this works out so that's what + + align:start position:0% +reason this works out so that's what + + + align:start position:0% +reason this works out so that's what +we're going to try to do now when we + + align:start position:0% +we're going to try to do now when we + + + align:start position:0% +we're going to try to do now when we +write an equation like this and more + + align:start position:0% +write an equation like this and more + + + align:start position:0% +write an equation like this and more +explicitly this means integral of size + + align:start position:0% +explicitly this means integral of size + + + align:start position:0% +explicitly this means integral of size +star of X and T Phi of X and T the X + + align:start position:0% +star of X and T Phi of X and T the X + + + align:start position:0% +star of X and T Phi of X and T the X +equal one you can imagine that not all + + align:start position:0% +equal one you can imagine that not all + + + align:start position:0% +equal one you can imagine that not all +kind of wave functions will satisfy it + + align:start position:0% +kind of wave functions will satisfy it + + + align:start position:0% +kind of wave functions will satisfy it +in particular any wave function for + + align:start position:0% +in particular any wave function for + + + align:start position:0% +in particular any wave function for +example that at infinity approaches a + + align:start position:0% +example that at infinity approaches a + + + align:start position:0% +example that at infinity approaches a +constant will never satisfy this because + + align:start position:0% +constant will never satisfy this because + + + align:start position:0% +constant will never satisfy this because +if at infinity you approach a constant + + align:start position:0% +if at infinity you approach a constant + + + align:start position:0% +if at infinity you approach a constant +then the integral is going to be + + align:start position:0% +then the integral is going to be + + + align:start position:0% +then the integral is going to be +infinite and it's just not gonna work + + align:start position:0% +infinite and it's just not gonna work + + + align:start position:0% +infinite and it's just not gonna work +out so you cannot the wave function + + align:start position:0% +out so you cannot the wave function + + + align:start position:0% +out so you cannot the wave function +cannot approach a finite number a finite + + align:start position:0% +cannot approach a finite number a finite + + + align:start position:0% +cannot approach a finite number a finite +constant as X goes to infinity so in + + align:start position:0% +constant as X goes to infinity so in + + + align:start position:0% +constant as X goes to infinity so in +order for this to hold + + align:start position:0% + + + + align:start position:0% + +order to warranty + + align:start position:0% + + + + align:start position:0% + +this can even hold can conceivably hold + + align:start position:0% + + + + align:start position:0% + +hold will require a bit of boundary + + align:start position:0% +hold will require a bit of boundary + + + align:start position:0% +hold will require a bit of boundary +conditions and will say that the limit + + align:start position:0% +conditions and will say that the limit + + + align:start position:0% +conditions and will say that the limit +as X goes to infinity or minus infinity + + align:start position:0% +as X goes to infinity or minus infinity + + + align:start position:0% +as X goes to infinity or minus infinity +plus minus infinity of sigh of X and T + + align:start position:0% +plus minus infinity of sigh of X and T + + + align:start position:0% +plus minus infinity of sigh of X and T +will be equal to zero it better be true + + align:start position:0% +will be equal to zero it better be true + + + align:start position:0% +will be equal to zero it better be true +and we'll ask a little more now you + + align:start position:0% +and we'll ask a little more now you + + + align:start position:0% +and we'll ask a little more now you +could say look certainly the limit of + + align:start position:0% +could say look certainly the limit of + + + align:start position:0% +could say look certainly the limit of +this function could not be a number + + align:start position:0% +this function could not be a number + + + align:start position:0% +this function could not be a number +because if it would be a nonzero number + + align:start position:0% +because if it would be a nonzero number + + + align:start position:0% +because if it would be a nonzero number +the integral will diverge but maybe + + align:start position:0% +the integral will diverge but maybe + + + align:start position:0% +the integral will diverge but maybe +there's no limit the wave function is so + + align:start position:0% +there's no limit the wave function is so + + + align:start position:0% +there's no limit the wave function is so +crazy that it can be integrated but + + align:start position:0% +crazy that it can be integrated but + + + align:start position:0% +crazy that it can be integrated but +suddenly it has a little spike and it + + align:start position:0% +suddenly it has a little spike and it + + + align:start position:0% +suddenly it has a little spike and it +just doesn't have a normal limit that + + align:start position:0% +just doesn't have a normal limit that + + + align:start position:0% +just doesn't have a normal limit that +could conceivably be the case + + align:start position:0% +could conceivably be the case + + + align:start position:0% +could conceivably be the case +nevertheless it doesn't seem to happen + + align:start position:0% +nevertheless it doesn't seem to happen + + + align:start position:0% +nevertheless it doesn't seem to happen +in any example that is of relevance so + + align:start position:0% +in any example that is of relevance so + + + align:start position:0% +in any example that is of relevance so +we will assume that the situations are + + align:start position:0% +we will assume that the situations are + + + align:start position:0% +we will assume that the situations are +not that crazy that this happens so + + align:start position:0% +not that crazy that this happens so + + + align:start position:0% +not that crazy that this happens so +we'll take wave functions that + + align:start position:0% +we'll take wave functions that + + + align:start position:0% +we'll take wave functions that +necessarily go to zero at infinity and + + align:start position:0% +necessarily go to zero at infinity and + + + align:start position:0% +necessarily go to zero at infinity and +that certainly is good it's a it's you + + align:start position:0% +that certainly is good it's a it's you + + + align:start position:0% +that certainly is good it's a it's you +cannot prove it's a necessary condition + + align:start position:0% +cannot prove it's a necessary condition + + + align:start position:0% +cannot prove it's a necessary condition +but if it holds it simplifies many many + + align:start position:0% +but if it holds it simplifies many many + + + align:start position:0% +but if it holds it simplifies many many +things and essentially if the wave + + align:start position:0% +things and essentially if the wave + + + align:start position:0% +things and essentially if the wave +function is good enough to have a limit + + align:start position:0% +function is good enough to have a limit + + + align:start position:0% +function is good enough to have a limit +then the limit must be zero the other + + align:start position:0% +then the limit must be zero the other + + + align:start position:0% +then the limit must be zero the other +thing that we will want is that + + align:start position:0% +thing that we will want is that + + + align:start position:0% +thing that we will want is that +sigh the X the limit as X goes to plus + + align:start position:0% +sigh the X the limit as X goes to plus + + + align:start position:0% +sigh the X the limit as X goes to plus +minus infinity is bounded that is yes + + align:start position:0% +minus infinity is bounded that is yes + + + align:start position:0% +minus infinity is bounded that is yes +the limit may exist and it may be a + + align:start position:0% +the limit may exist and it may be a + + + align:start position:0% +the limit may exist and it may be a +number but is not infinite and in every + + align:start position:0% +number but is not infinite and in every + + + align:start position:0% +number but is not infinite and in every +example that I know in front when this + + align:start position:0% +example that I know in front when this + + + align:start position:0% +example that I know in front when this +goes to zero this goes to zero as well + + align:start position:0% +goes to zero this goes to zero as well + + + align:start position:0% +goes to zero this goes to zero as well +but this is basically all you will ever + + align:start position:0% +but this is basically all you will ever + + + align:start position:0% +but this is basically all you will ever +need in order to make sense of the wave + + align:start position:0% +need in order to make sense of the wave + + + align:start position:0% +need in order to make sense of the wave +functions and their integrals that we're + + align:start position:0% +functions and their integrals that we're + + + align:start position:0% +functions and their integrals that we're +going to be doing now you shouldn't be + + align:start position:0% +going to be doing now you shouldn't be + + + align:start position:0% +going to be doing now you shouldn't be +too surprised that you need to say + + align:start position:0% +too surprised that you need to say + + + align:start position:0% +too surprised that you need to say +something about this wave function in + + align:start position:0% +something about this wave function in + + + align:start position:0% +something about this wave function in +the analysis that will follow because + + align:start position:0% +the analysis that will follow because + + + align:start position:0% +the analysis that will follow because +the derivative you have the wave + + align:start position:0% +the derivative you have the wave + + + align:start position:0% +the derivative you have the wave +function its derivative because + + align:start position:0% +function its derivative because + + + align:start position:0% +function its derivative because +certainly there are two derivatives here + + align:start position:0% +certainly there are two derivatives here + + + align:start position:0% +certainly there are two derivatives here +so it's when we manipulate this + + align:start position:0% +so it's when we manipulate this + + + align:start position:0% +so it's when we manipulate this +quantities inside an integrals you will + + align:start position:0% +quantities inside an integrals you will + + + align:start position:0% +quantities inside an integrals you will +see very soon single derivatives will + + align:start position:0% +see very soon single derivatives will + + + align:start position:0% +see very soon single derivatives will +show up and we will have to control them + + align:start position:0% +show up and we will have to control them + + + align:start position:0% +show up and we will have to control them +so so the only thing that I'm saying is + + align:start position:0% +so so the only thing that I'm saying is + + + align:start position:0% +so so the only thing that I'm saying is +that when you see a wave function that + + align:start position:0% +that when you see a wave function that + + + align:start position:0% +that when you see a wave function that +satisfies this property you know that + + align:start position:0% +satisfies this property you know that + + + align:start position:0% +satisfies this property you know that +unless the function is extremely crazy + + align:start position:0% +unless the function is extremely crazy + + + align:start position:0% +unless the function is extremely crazy +it's a function that goes to zero at + + align:start position:0% +it's a function that goes to zero at + + + align:start position:0% +it's a function that goes to zero at +plus minus infinity and it's derivative + + align:start position:0% +plus minus infinity and it's derivative + + + align:start position:0% +plus minus infinity and it's derivative +presumably also goes to zero but it will + + align:start position:0% +presumably also goes to zero but it will + + + align:start position:0% +presumably also goes to zero but it will +be enough to say that it maybe goes to a + + align:start position:0% +be enough to say that it maybe goes to a + + + align:start position:0% +be enough to say that it maybe goes to a +number now there is another possibility + + align:start position:0% +number now there is another possibility + + + align:start position:0% +number now there is another possibility +I think for confusion here with things + + align:start position:0% +I think for confusion here with things + + + align:start position:0% +I think for confusion here with things +that we've been saying before we've said + + align:start position:0% +that we've been saying before we've said + + + align:start position:0% +that we've been saying before we've said +before that the physics of a wave + + align:start position:0% +before that the physics of a wave + + + align:start position:0% +before that the physics of a wave +function + + align:start position:0% +function + + + align:start position:0% +function +is not altered by multiplying the + + align:start position:0% +is not altered by multiplying the + + + align:start position:0% +is not altered by multiplying the +wavefunction by a number we said that + + align:start position:0% +wavefunction by a number we said that + + + align:start position:0% +wavefunction by a number we said that +psy added oops I is the same state size + + align:start position:0% +psy added oops I is the same state size + + + align:start position:0% +psy added oops I is the same state size +the same state at square root of tube + + align:start position:0% +the same state at square root of tube + + + align:start position:0% +the same state at square root of tube +sigh all this is the same physics but + + align:start position:0% +sigh all this is the same physics but + + + align:start position:0% +sigh all this is the same physics but +here it looks a little surprising if you + + align:start position:0% +here it looks a little surprising if you + + + align:start position:0% +here it looks a little surprising if you +wish because if I have a pie and I got + + align:start position:0% +wish because if I have a pie and I got + + + align:start position:0% +wish because if I have a pie and I got +this already working out if I multiply + + align:start position:0% +this already working out if I multiply + + + align:start position:0% +this already working out if I multiply +psi by square root of two it will not + + align:start position:0% +psi by square root of two it will not + + + align:start position:0% +psi by square root of two it will not +hold so there seems to be a little maybe + + align:start position:0% +hold so there seems to be a little maybe + + + align:start position:0% +hold so there seems to be a little maybe +something with the words that we've been + + align:start position:0% +something with the words that we've been + + + align:start position:0% +something with the words that we've been +using it's not exactly right and I want + + align:start position:0% +using it's not exactly right and I want + + + align:start position:0% +using it's not exactly right and I want +to make sure there's no room for + + align:start position:0% +to make sure there's no room for + + + align:start position:0% +to make sure there's no room for +confusion here and it's it's the + + align:start position:0% +confusion here and it's it's the + + + align:start position:0% +confusion here and it's it's the +following fact here this wavefunction + + align:start position:0% +following fact here this wavefunction + + + align:start position:0% +following fact here this wavefunction +has been normalized so there's two kinds + + align:start position:0% +has been normalized so there's two kinds + + + align:start position:0% +has been normalized so there's two kinds +of wave functions that you can have we + + align:start position:0% +of wave functions that you can have we + + + align:start position:0% +of wave functions that you can have we +functions that can be normalized and we + + align:start position:0% +functions that can be normalized and we + + + align:start position:0% +functions that can be normalized and we +functions cannot be normal I suppose + + align:start position:0% +functions cannot be normal I suppose + + + align:start position:0% +functions cannot be normal I suppose +somebody comes to you and gives you up + + align:start position:0% +somebody comes to you and gives you up + + + align:start position:0% +somebody comes to you and gives you up +size of X and T or let's assume we give + + align:start position:0% +size of X and T or let's assume we give + + + align:start position:0% +size of X and T or let's assume we give +subside an output X and T no problem now + + align:start position:0% +subside an output X and T no problem now + + + align:start position:0% +subside an output X and T no problem now +suppose you go and start doing this + + align:start position:0% +suppose you go and start doing this + + + align:start position:0% +suppose you go and start doing this +integral integral of Phi squared DX and + + align:start position:0% +integral integral of Phi squared DX and + + + align:start position:0% +integral integral of Phi squared DX and +then you find that it's not equal to 1 + + align:start position:0% +then you find that it's not equal to 1 + + + align:start position:0% +then you find that it's not equal to 1 +but is equal to some value n which is + + align:start position:0% +but is equal to some value n which is + + + align:start position:0% +but is equal to some value n which is +different from woman maybe if this + + align:start position:0% +different from woman maybe if this + + + align:start position:0% +different from woman maybe if this +happens we say that psy is normalizable + + align:start position:0% + + + + align:start position:0% + +which means it can be normalized and + + align:start position:0% +which means it can be normalized and + + + align:start position:0% +which means it can be normalized and +using this idea that changing the value + + align:start position:0% +using this idea that changing the value + + + align:start position:0% +using this idea that changing the value +the coefficient of the function doesn't + + align:start position:0% +the coefficient of the function doesn't + + + align:start position:0% +the coefficient of the function doesn't +change it too much we simply say use + + align:start position:0% +change it too much we simply say use + + + align:start position:0% +change it too much we simply say use +instead + + align:start position:0% + + + + align:start position:0% + +oops I prime which is equal to psi over + + align:start position:0% +oops I prime which is equal to psi over + + + align:start position:0% +oops I prime which is equal to psi over +square root of N and look what the nice + + align:start position:0% +square root of N and look what the nice + + + align:start position:0% +square root of N and look what the nice +property this side Prime has if you + + align:start position:0% +property this side Prime has if you + + + align:start position:0% +property this side Prime has if you +integrate sie prime squared it would be + + align:start position:0% +integrate sie prime squared it would be + + + align:start position:0% +integrate sie prime squared it would be +equal because you have side prime here + + align:start position:0% +equal because you have side prime here + + + align:start position:0% +equal because you have side prime here +squared would be equal to the integral + + align:start position:0% +squared would be equal to the integral + + + align:start position:0% +squared would be equal to the integral +of size squared divided by the number n + + align:start position:0% +of size squared divided by the number n + + + align:start position:0% +of size squared divided by the number n +because it's two of them DX and that's + + align:start position:0% +because it's two of them DX and that's + + + align:start position:0% +because it's two of them DX and that's +the number goes out and you have the + + align:start position:0% +the number goes out and you have the + + + align:start position:0% +the number goes out and you have the +integral of size squared DX + + align:start position:0% +integral of size squared DX + + + align:start position:0% +integral of size squared DX +but that integral was exactly in so + + align:start position:0% +but that integral was exactly in so + + + align:start position:0% +but that integral was exactly in so +that's one so if your wave function has + + align:start position:0% +that's one so if your wave function has + + + align:start position:0% +that's one so if your wave function has +a finite integral in this sense a number + + align:start position:0% +a finite integral in this sense a number + + + align:start position:0% +a finite integral in this sense a number +that is less than infinity then sigh can + + align:start position:0% +that is less than infinity then sigh can + + + align:start position:0% +that is less than infinity then sigh can +be normalized and if you're gonna work + + align:start position:0% +be normalized and if you're gonna work + + + align:start position:0% +be normalized and if you're gonna work +with probabilities you should use + + align:start position:0% +with probabilities you should use + + + align:start position:0% +with probabilities you should use +instead this wave function which is the + + align:start position:0% +instead this wave function which is the + + + align:start position:0% +instead this wave function which is the +original wave function divided by a + + align:start position:0% +original wave function divided by a + + + align:start position:0% +original wave function divided by a +number so the idea is that in some sense + + align:start position:0% +number so the idea is that in some sense + + + align:start position:0% +number so the idea is that in some sense +you can be lay all of this and you can + + align:start position:0% +you can be lay all of this and you can + + + align:start position:0% +you can be lay all of this and you can +always work with wave functions that + + align:start position:0% +always work with wave functions that + + + align:start position:0% +always work with wave functions that +our normalizable but only when you're + + align:start position:0% +our normalizable but only when you're + + + align:start position:0% +our normalizable but only when you're +going to calculate your probabilities + + align:start position:0% +going to calculate your probabilities + + + align:start position:0% +going to calculate your probabilities +you can take the trouble to actually + + align:start position:0% +you can take the trouble to actually + + + align:start position:0% +you can take the trouble to actually +normalize them and those are the ones + + align:start position:0% +normalize them and those are the ones + + + align:start position:0% +normalize them and those are the ones +you use in this formulas so so the idea + + align:start position:0% +you use in this formulas so so the idea + + + align:start position:0% +you use in this formulas so so the idea +remains that we work flexibly with wave + + align:start position:0% +remains that we work flexibly with wave + + + align:start position:0% +remains that we work flexibly with wave +functions and multiply them by numbers + + align:start position:0% +functions and multiply them by numbers + + + align:start position:0% +functions and multiply them by numbers +and nothing changes as long as you + + align:start position:0% +and nothing changes as long as you + + + align:start position:0% +and nothing changes as long as you +realize that you cannot change the fact + + align:start position:0% +realize that you cannot change the fact + + + align:start position:0% +realize that you cannot change the fact +that the wave function is normalizable + + align:start position:0% +that the wave function is normalizable + + + align:start position:0% +that the wave function is normalizable +by multiplying it by any finite number + + align:start position:0% +by multiplying it by any finite number + + + align:start position:0% +by multiplying it by any finite number +it will still be normalizable and if + + align:start position:0% +it will still be normalizable and if + + + align:start position:0% +it will still be normalizable and if +it's normalizable it's equivalent to a + + align:start position:0% +it's normalizable it's equivalent to a + + + align:start position:0% +it's normalizable it's equivalent to a +normalized wave function so those two + + align:start position:0% +normalized wave function so those two + + + align:start position:0% +normalized wave function so those two +words sound very similar but they're a + + align:start position:0% +words sound very similar but they're a + + + align:start position:0% +words sound very similar but they're a +little different + + align:start position:0% +little different + + + align:start position:0% +little different +one is normalizable which means it has + + align:start position:0% +one is normalizable which means it has + + + align:start position:0% +one is normalizable which means it has +into a sigh squared + + align:start position:0% +into a sigh squared + + + align:start position:0% +into a sigh squared +finite and normalize is one that already + + align:start position:0% +finite and normalize is one that already + + + align:start position:0% +finite and normalize is one that already +has been adjusted to do this and can be + + align:start position:0% +has been adjusted to do this and can be + + + align:start position:0% +has been adjusted to do this and can be +used to define a probability + + align:start position:0% +used to define a probability + + + align:start position:0% +used to define a probability +distribution okay so that's in a way of + + align:start position:0% +distribution okay so that's in a way of + + + align:start position:0% +distribution okay so that's in a way of +introduction to the problem that we have + + align:start position:0% +introduction to the problem that we have + + + align:start position:0% +introduction to the problem that we have +to do our serious problem is indeed + + align:start position:0% +to do our serious problem is indeed + + + align:start position:0% +to do our serious problem is indeed +justifying that the time evolution + + align:start position:0% +justifying that the time evolution + + + align:start position:0% +justifying that the time evolution +doesn't mess up the normalization and + + align:start position:0% +doesn't mess up the normalization and + + + align:start position:0% +doesn't mess up the normalization and +how does it do that \ No newline at end of file diff --git a/dCw-x9ZOljY.txt b/dCw-x9ZOljY.txt new file mode 100644 index 0000000000000000000000000000000000000000..14de998cf4f94f7c4993f145ec5fd1428d263750 --- /dev/null +++ b/dCw-x9ZOljY.txt @@ -0,0 +1,11667 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT OpenCourseWare continue to + + align:start position:0% +will help MIT OpenCourseWare continue to + + + align:start position:0% +will help MIT OpenCourseWare continue to +offer high quality educational resources + + align:start position:0% +offer high quality educational resources + + + align:start position:0% +offer high quality educational resources +for free + + align:start position:0% +for free + + + align:start position:0% +for free +to make a donation or to view additional + + align:start position:0% +to make a donation or to view additional + + + align:start position:0% +to make a donation or to view additional +materials from hundreds of MIT courses + + align:start position:0% +materials from hundreds of MIT courses + + + align:start position:0% +materials from hundreds of MIT courses +visit MIT opencourseware at ocw.mit.edu + + align:start position:0% + + + + align:start position:0% + +the founding of Ghent a little bit about + + align:start position:0% +the founding of Ghent a little bit about + + + align:start position:0% +the founding of Ghent a little bit about +the old Herbert Boyer ms4 1936 he was a + + align:start position:0% +the old Herbert Boyer ms4 1936 he was a + + + align:start position:0% +the old Herbert Boyer ms4 1936 he was a +biochemist from Pennsylvania in Orgeon + + align:start position:0% +biochemist from Pennsylvania in Orgeon + + + align:start position:0% +biochemist from Pennsylvania in Orgeon +Pennsylvania and then worked at the + + align:start position:0% +Pennsylvania and then worked at the + + + align:start position:0% +Pennsylvania and then worked at the +University of California in San + + align:start position:0% +University of California in San + + + align:start position:0% +University of California in San +Francisco and he's sort of considered + + align:start position:0% +Francisco and he's sort of considered + + + align:start position:0% +Francisco and he's sort of considered +one of the first pioneers in the field + + align:start position:0% +one of the first pioneers in the field + + + align:start position:0% +one of the first pioneers in the field +of molecular genetics and they also have + + align:start position:0% +of molecular genetics and they also have + + + align:start position:0% +of molecular genetics and they also have +Roberts Wednesday who was born in 1947 + + align:start position:0% +Roberts Wednesday who was born in 1947 + + + align:start position:0% +Roberts Wednesday who was born in 1947 +and died 1999 he was from Brooklyn went + + align:start position:0% +and died 1999 he was from Brooklyn went + + + align:start position:0% +and died 1999 he was from Brooklyn went +to MIT and then eventually got into + + align:start position:0% +to MIT and then eventually got into + + + align:start position:0% +to MIT and then eventually got into +venture capital and he was instrumental + + align:start position:0% +venture capital and he was instrumental + + + align:start position:0% +venture capital and he was instrumental +in finding that finding denatech and + + align:start position:0% +in finding that finding denatech and + + + align:start position:0% +in finding that finding denatech and +kind of developing the financing + + align:start position:0% +kind of developing the financing + + + align:start position:0% +kind of developing the financing +structure for that + + align:start position:0% +structure for that + + + align:start position:0% +structure for that +so he's enlisted some other players that + + align:start position:0% +so he's enlisted some other players that + + + align:start position:0% +so he's enlisted some other players that +were involved they kind of came in + + align:start position:0% +were involved they kind of came in + + + align:start position:0% +were involved they kind of came in +through out the process of various + + align:start position:0% +through out the process of various + + + align:start position:0% +through out the process of various +talents that were recruited both + + align:start position:0% +talents that were recruited both + + + align:start position:0% +talents that were recruited both +nationally and internationally + + align:start position:0% +nationally and internationally + + + align:start position:0% +nationally and internationally +Boyer worked with Arthur Riggs and he + + align:start position:0% +Boyer worked with Arthur Riggs and he + + + align:start position:0% +Boyer worked with Arthur Riggs and he +took it Akua from the Beckman Research + + align:start position:0% +took it Akua from the Beckman Research + + + align:start position:0% +took it Akua from the Beckman Research +Institute and the group had become the + + align:start position:0% +Institute and the group had become the + + + align:start position:0% +Institute and the group had become the +first to successfully express a human + + align:start position:0% +first to successfully express a human + + + align:start position:0% +first to successfully express a human +gene in bacteria when they produced when + + align:start position:0% +gene in bacteria when they produced when + + + align:start position:0% +gene in bacteria when they produced when +they produce somatostatin in 1977 and + + align:start position:0% +they produce somatostatin in 1977 and + + + align:start position:0% +they produce somatostatin in 1977 and +then David god--all and Dennis quite as + + align:start position:0% +then David god--all and Dennis quite as + + + align:start position:0% +then David god--all and Dennis quite as +well were brought on later on in 1978 I + + align:start position:0% +well were brought on later on in 1978 I + + + align:start position:0% +well were brought on later on in 1978 I +believe yeah and they were they went on + + align:start position:0% +believe yeah and they were they went on + + + align:start position:0% +believe yeah and they were they went on +to be instrumental figures in the + + align:start position:0% +to be instrumental figures in the + + + align:start position:0% +to be instrumental figures in the +company as well so I'll go into a little + + align:start position:0% +company as well so I'll go into a little + + + align:start position:0% +company as well so I'll go into a little +bit about what they what they + + align:start position:0% +bit about what they what they + + + align:start position:0% +bit about what they what they +accomplished just sort of the early + + align:start position:0% +accomplished just sort of the early + + + align:start position:0% +accomplished just sort of the early +history of the company there really were + + align:start position:0% +history of the company there really were + + + align:start position:0% +history of the company there really were +the first kind of kick-started the + + align:start position:0% +the first kind of kick-started the + + + align:start position:0% +the first kind of kick-started the +American biotech industry and you know + + align:start position:0% +American biotech industry and you know + + + align:start position:0% +American biotech industry and you know +it all started when the two of them kind + + align:start position:0% +it all started when the two of them kind + + + align:start position:0% +it all started when the two of them kind +of met Bob Bob Blair and Swanson met + + align:start position:0% +of met Bob Bob Blair and Swanson met + + + align:start position:0% +of met Bob Bob Blair and Swanson met +over beer and they've done $500 to + + align:start position:0% +over beer and they've done $500 to + + + align:start position:0% +over beer and they've done $500 to +stretch his pharmaceutical company that + + align:start position:0% +stretch his pharmaceutical company that + + + align:start position:0% +stretch his pharmaceutical company that +would explore proteins a bacterial + + align:start position:0% +would explore proteins a bacterial + + + align:start position:0% +would explore proteins a bacterial +engineer + + align:start position:0% +engineer + + + align:start position:0% +engineer +and the first targeted human the first + + align:start position:0% +and the first targeted human the first + + + align:start position:0% +and the first targeted human the first +targeted human insulin because you know + + align:start position:0% +targeted human insulin because you know + + + align:start position:0% +targeted human insulin because you know +that was kind of a competitive area at + + align:start position:0% +that was kind of a competitive area at + + + align:start position:0% +that was kind of a competitive area at +the time and there was a lot of demand + + align:start position:0% +the time and there was a lot of demand + + + align:start position:0% +the time and there was a lot of demand +for treatments but there was a worry + + align:start position:0% +for treatments but there was a worry + + + align:start position:0% +for treatments but there was a worry +that there wasn't enough and people have + + align:start position:0% +that there wasn't enough and people have + + + align:start position:0% +that there wasn't enough and people have +animal until inter meet those rising + + align:start position:0% +animal until inter meet those rising + + + align:start position:0% +animal until inter meet those rising +demand so they've kind of decided + + align:start position:0% +demand so they've kind of decided + + + align:start position:0% +demand so they've kind of decided +working to make synthetic insulin up to + + align:start position:0% +working to make synthetic insulin up to + + + align:start position:0% +working to make synthetic insulin up to +scratch and be competitive with what was + + align:start position:0% +scratch and be competitive with what was + + + align:start position:0% +scratch and be competitive with what was +previously used and they targeted + + align:start position:0% +previously used and they targeted + + + align:start position:0% +previously used and they targeted +meeting the requirements of Eli Lilly + + align:start position:0% +meeting the requirements of Eli Lilly + + + align:start position:0% +meeting the requirements of Eli Lilly +who they could have wanted to get his + + align:start position:0% +who they could have wanted to get his + + + align:start position:0% +who they could have wanted to get his +business to be they targeted his + + align:start position:0% +business to be they targeted his + + + align:start position:0% +business to be they targeted his +requirements they could get his business + + align:start position:0% +requirements they could get his business + + + align:start position:0% +requirements they could get his business +eventually and get the company going + + align:start position:0% +eventually and get the company going + + + align:start position:0% +eventually and get the company going +so getting money and was kind of a tough + + align:start position:0% +so getting money and was kind of a tough + + + align:start position:0% +so getting money and was kind of a tough +process for the you know throughout the + + align:start position:0% +process for the you know throughout the + + + align:start position:0% +process for the you know throughout the +entire time they both some really staked + + align:start position:0% +entire time they both some really staked + + + align:start position:0% +entire time they both some really staked +a lot of their career on this endeavor + + align:start position:0% +a lot of their career on this endeavor + + + align:start position:0% +a lot of their career on this endeavor +and Swanson + + align:start position:0% +and Swanson + + + align:start position:0% +and Swanson +at the time was very young and went + + align:start position:0% +at the time was very young and went + + + align:start position:0% +at the time was very young and went +through many periods of unemployment as + + align:start position:0% +through many periods of unemployment as + + + align:start position:0% +through many periods of unemployment as +he was trying to you know get the money + + align:start position:0% +he was trying to you know get the money + + + align:start position:0% +he was trying to you know get the money +for financing this man-boy continuing + + align:start position:0% +for financing this man-boy continuing + + + align:start position:0% +for financing this man-boy continuing +his his day job teaching so eventually + + align:start position:0% + + + + align:start position:0% + +so the they branded to many obstacles + + align:start position:0% +so the they branded to many obstacles + + + align:start position:0% +so the they branded to many obstacles +financially but they also at the time + + align:start position:0% +financially but they also at the time + + + align:start position:0% +financially but they also at the time +when they decided to bank target humans + + align:start position:0% +when they decided to bank target humans + + + align:start position:0% +when they decided to bank target humans +in the first place that kind of + + align:start position:0% +in the first place that kind of + + + align:start position:0% +in the first place that kind of +kick-started a nationwide race to do + + align:start position:0% +kick-started a nationwide race to do + + + align:start position:0% +kick-started a nationwide race to do +this and so there was a group at Harvard + + align:start position:0% +this and so there was a group at Harvard + + + align:start position:0% +this and so there was a group at Harvard +and another group at some another + + align:start position:0% +and another group at some another + + + align:start position:0% +and another group at some another +university in California blanking on the + + align:start position:0% +university in California blanking on the + + + align:start position:0% +university in California blanking on the +name but yeah they it was a they're + + align:start position:0% +name but yeah they it was a they're + + + align:start position:0% +name but yeah they it was a they're +particularly formidable rivals and they + + align:start position:0% +particularly formidable rivals and they + + + align:start position:0% +particularly formidable rivals and they +had those other two groups were kind of + + align:start position:0% +had those other two groups were kind of + + + align:start position:0% +had those other two groups were kind of +entrenched in academia and they had all + + align:start position:0% +entrenched in academia and they had all + + + align:start position:0% +entrenched in academia and they had all +the resources that you brought them + + align:start position:0% +the resources that you brought them + + + align:start position:0% +the resources that you brought them +whereas Boyer influence and were + + align:start position:0% +whereas Boyer influence and were + + + align:start position:0% +whereas Boyer influence and were +relatively resource poor but they had + + align:start position:0% +relatively resource poor but they had + + + align:start position:0% +relatively resource poor but they had +one advantage that he was working for I + + align:start position:0% +one advantage that he was working for I + + + align:start position:0% +one advantage that he was working for I +was working with synthetic DNA which + + align:start position:0% +was working with synthetic DNA which + + + align:start position:0% +was working with synthetic DNA which +would allow him to get around + + align:start position:0% +would allow him to get around + + + align:start position:0% +would allow him to get around +regulations at the NIH put on natural + + align:start position:0% +regulations at the NIH put on natural + + + align:start position:0% +regulations at the NIH put on natural +DNA during this process so they faced a + + align:start position:0% +DNA during this process so they faced a + + + align:start position:0% +DNA during this process so they faced a +lot of other obstacles and but they + + align:start position:0% +lot of other obstacles and but they + + + align:start position:0% +lot of other obstacles and but they +still had advantages other teams still + + align:start position:0% +still had advantages other teams still + + + align:start position:0% +still had advantages other teams still +advantages of scale and sales ability + + align:start position:0% +advantages of scale and sales ability + + + align:start position:0% +advantages of scale and sales ability +Swanson goal was to make Genentech a + + align:start position:0% +Swanson goal was to make Genentech a + + + align:start position:0% +Swanson goal was to make Genentech a +fully integrated pharmaceutical company + + align:start position:0% +fully integrated pharmaceutical company + + + align:start position:0% +fully integrated pharmaceutical company +and they wanted the eventual goal is to + + align:start position:0% +and they wanted the eventual goal is to + + + align:start position:0% +and they wanted the eventual goal is to +be able to produce and sell a wide range + + align:start position:0% +be able to produce and sell a wide range + + + align:start position:0% +be able to produce and sell a wide range +of drugs + + align:start position:0% +of drugs + + + align:start position:0% +of drugs +and they believe that if they were the + + align:start position:0% +and they believe that if they were the + + + align:start position:0% +and they believe that if they were the +first to make the issue and that we will + + align:start position:0% +first to make the issue and that we will + + + align:start position:0% +first to make the issue and that we will +that would give them the lift up in the + + align:start position:0% +that would give them the lift up in the + + + align:start position:0% +that would give them the lift up in the +industry that they needed so Swanson + + align:start position:0% +industry that they needed so Swanson + + + align:start position:0% +industry that they needed so Swanson +wanted a hiring spree and recruited + + align:start position:0% +wanted a hiring spree and recruited + + + align:start position:0% +wanted a hiring spree and recruited +talent they were able to evoke open up + + align:start position:0% +talent they were able to evoke open up + + + align:start position:0% +talent they were able to evoke open up +their own lab eventually he was able to + + align:start position:0% +their own lab eventually he was able to + + + align:start position:0% +their own lab eventually he was able to +get a hundred K from various sources for + + align:start position:0% +get a hundred K from various sources for + + + align:start position:0% +get a hundred K from various sources for +that initial push so eventually by + + align:start position:0% +that initial push so eventually by + + + align:start position:0% +that initial push so eventually by +August of 1978 we were able to make the + + align:start position:0% +August of 1978 we were able to make the + + + align:start position:0% +August of 1978 we were able to make the +first 20 nanograms of these and they + + align:start position:0% +first 20 nanograms of these and they + + + align:start position:0% +first 20 nanograms of these and they +immediately contacted UI Lilly and + + align:start position:0% +immediately contacted UI Lilly and + + + align:start position:0% +immediately contacted UI Lilly and +sponson kind of went against Convention + + align:start position:0% +sponson kind of went against Convention + + + align:start position:0% +sponson kind of went against Convention +and how does this huge televised press + + align:start position:0% +and how does this huge televised press + + + align:start position:0% +and how does this huge televised press +conference where he announced that the + + align:start position:0% +conference where he announced that the + + + align:start position:0% +conference where he announced that the +achieve what they wanted to achieve and + + align:start position:0% +achieve what they wanted to achieve and + + + align:start position:0% +achieve what they wanted to achieve and +that kind of do it he attended and quit + + align:start position:0% +that kind of do it he attended and quit + + + align:start position:0% +that kind of do it he attended and quit +Genentech really put it on the map and + + align:start position:0% +Genentech really put it on the map and + + + align:start position:0% +Genentech really put it on the map and +in the public eye and eventually you + + align:start position:0% +in the public eye and eventually you + + + align:start position:0% +in the public eye and eventually you +know Eli ladies company came forward + + align:start position:0% +know Eli ladies company came forward + + + align:start position:0% +know Eli ladies company came forward +with ten million dollars for genetic and + + align:start position:0% +with ten million dollars for genetic and + + + align:start position:0% +with ten million dollars for genetic and +they were eventually able to pass track + + align:start position:0% +they were eventually able to pass track + + + align:start position:0% +they were eventually able to pass track +it for industrial production and in 1980 + + align:start position:0% +it for industrial production and in 1980 + + + align:start position:0% +it for industrial production and in 1980 +they had their IPO it was one of the + + align:start position:0% +they had their IPO it was one of the + + + align:start position:0% +they had their IPO it was one of the +most protected IPOs seen from this + + align:start position:0% +most protected IPOs seen from this + + + align:start position:0% +most protected IPOs seen from this +industry and they were eventually able + + align:start position:0% +industry and they were eventually able + + + align:start position:0% +industry and they were eventually able +to in 1985 they were able to release a + + align:start position:0% +to in 1985 they were able to release a + + + align:start position:0% +to in 1985 they were able to release a +second drug and these are some of the + + align:start position:0% +second drug and these are some of the + + + align:start position:0% +second drug and these are some of the +early products + + align:start position:0% + + + + align:start position:0% + +yeah so going on to the types of + + align:start position:0% +yeah so going on to the types of + + + align:start position:0% +yeah so going on to the types of +qualities of great groups that we've + + align:start position:0% +qualities of great groups that we've + + + align:start position:0% +qualities of great groups that we've +been talking about so I think one of the + + align:start position:0% +been talking about so I think one of the + + + align:start position:0% +been talking about so I think one of the +main things was Swanson's leadership so + + align:start position:0% +main things was Swanson's leadership so + + + align:start position:0% +main things was Swanson's leadership so +the article mentioned that he had a very + + align:start position:0% +the article mentioned that he had a very + + + align:start position:0% +the article mentioned that he had a very +down-to-earth style and was the look + + align:start position:0% +down-to-earth style and was the look + + + align:start position:0% +down-to-earth style and was the look +that connected with everyone who was + + align:start position:0% +that connected with everyone who was + + + align:start position:0% +that connected with everyone who was +involved as well as a great generosity + + align:start position:0% +involved as well as a great generosity + + + align:start position:0% +involved as well as a great generosity +towards everybody and so he was he + + align:start position:0% +towards everybody and so he was he + + + align:start position:0% +towards everybody and so he was he +offered basically everyone from the top + + align:start position:0% +offered basically everyone from the top + + + align:start position:0% +offered basically everyone from the top +scientists to the custodians a share of + + align:start position:0% +scientists to the custodians a share of + + + align:start position:0% +scientists to the custodians a share of +a company at one point and you had a + + align:start position:0% +a company at one point and you had a + + + align:start position:0% +a company at one point and you had a +really great effective recruitment of + + align:start position:0% +really great effective recruitment of + + + align:start position:0% +really great effective recruitment of +talent he was able to see where they + + align:start position:0% +talent he was able to see where they + + + align:start position:0% +talent he was able to see where they +needed people and had that good for that + + align:start position:0% +needed people and had that good for that + + + align:start position:0% +needed people and had that good for that +those positions another really important + + align:start position:0% +those positions another really important + + + align:start position:0% +those positions another really important +one for an element is that there was a + + align:start position:0% +one for an element is that there was a + + + align:start position:0% +one for an element is that there was a +real conviction of cause so Boyer + + align:start position:0% +real conviction of cause so Boyer + + + align:start position:0% +real conviction of cause so Boyer +initially wanted to get into + + align:start position:0% +initially wanted to get into + + + align:start position:0% +initially wanted to get into +commercialization because he felt that + + align:start position:0% +commercialization because he felt that + + + align:start position:0% +commercialization because he felt that +university research and + + align:start position:0% +university research and + + + align:start position:0% +university research and +government-funded research wouldn't + + align:start position:0% +government-funded research wouldn't + + + align:start position:0% +government-funded research wouldn't +allow him to see the real benefits + + align:start position:0% +allow him to see the real benefits + + + align:start position:0% +allow him to see the real benefits +practical benefits of this work so it's + + align:start position:0% +practical benefits of this work so it's + + + align:start position:0% +practical benefits of this work so it's +kind of a really altruistic goal of his + + align:start position:0% +kind of a really altruistic goal of his + + + align:start position:0% +kind of a really altruistic goal of his +and that mission kind of carried them + + align:start position:0% +and that mission kind of carried them + + + align:start position:0% +and that mission kind of carried them +out okay I think throughout this process + + align:start position:0% +out okay I think throughout this process + + + align:start position:0% +out okay I think throughout this process +that they were going to be making + + align:start position:0% +that they were going to be making + + + align:start position:0% +that they were going to be making +something that would better people's + + align:start position:0% +something that would better people's + + + align:start position:0% +something that would better people's +lives save lives another important + + align:start position:0% +lives save lives another important + + + align:start position:0% +lives save lives another important +element is that they were working + + align:start position:0% +element is that they were working + + + align:start position:0% +element is that they were working +against a common enemy so it wasn't + + align:start position:0% +against a common enemy so it wasn't + + + align:start position:0% +against a common enemy so it wasn't +exactly an enemy but they were there + + align:start position:0% +exactly an enemy but they were there + + + align:start position:0% +exactly an enemy but they were there +were those other teams that they were + + align:start position:0% +were those other teams that they were + + + align:start position:0% +were those other teams that they were +working against and that competition + + align:start position:0% +working against and that competition + + + align:start position:0% +working against and that competition +really filled them and going along with + + align:start position:0% +really filled them and going along with + + + align:start position:0% +really filled them and going along with +that they were kind of like the + + align:start position:0% +that they were kind of like the + + + align:start position:0% +that they were kind of like the +underdogs and the young company that + + align:start position:0% +underdogs and the young company that + + + align:start position:0% +underdogs and the young company that +didn't have the resources and didn't + + align:start position:0% +didn't have the resources and didn't + + + align:start position:0% +didn't have the resources and didn't +have the funding so that really was + + align:start position:0% +have the funding so that really was + + + align:start position:0% +have the funding so that really was +another motivating factor as well yeah + + align:start position:0% +another motivating factor as well yeah + + + align:start position:0% +another motivating factor as well yeah +another one is optimism and a degree of + + align:start position:0% +another one is optimism and a degree of + + + align:start position:0% +another one is optimism and a degree of +naivete so that kind of came in to play + + align:start position:0% +naivete so that kind of came in to play + + + align:start position:0% +naivete so that kind of came in to play +when they first made insulin but Eli + + align:start position:0% +when they first made insulin but Eli + + + align:start position:0% +when they first made insulin but Eli +Lilly said that they needed had put + + align:start position:0% +Lilly said that they needed had put + + + align:start position:0% +Lilly said that they needed had put +really strict timeline on them for + + align:start position:0% +really strict timeline on them for + + + align:start position:0% +really strict timeline on them for +developing it for industrial production + + align:start position:0% +developing it for industrial production + + + align:start position:0% +developing it for industrial production +and most people would have said that + + align:start position:0% +and most people would have said that + + + align:start position:0% +and most people would have said that +that was impossible and that they + + align:start position:0% +that was impossible and that they + + + align:start position:0% +that was impossible and that they +couldn't do that in that timeframe but + + align:start position:0% +couldn't do that in that timeframe but + + + align:start position:0% +couldn't do that in that timeframe but +they were none the wiser and kind of + + align:start position:0% +they were none the wiser and kind of + + + align:start position:0% +they were none the wiser and kind of +went for it anyways and + + align:start position:0% +went for it anyways and + + + align:start position:0% +went for it anyways and +it end up working out working out for + + align:start position:0% +it end up working out working out for + + + align:start position:0% +it end up working out working out for +them another thing is that the people + + align:start position:0% +them another thing is that the people + + + align:start position:0% +them another thing is that the people +were not interchangeable so like I said + + align:start position:0% +were not interchangeable so like I said + + + align:start position:0% +were not interchangeable so like I said +before they read there were that list of + + align:start position:0% +before they read there were that list of + + + align:start position:0% +before they read there were that list of +places that I showed you were very + + align:start position:0% +places that I showed you were very + + + align:start position:0% +places that I showed you were very +instrumental and they weren't specific + + align:start position:0% +instrumental and they weren't specific + + + align:start position:0% +instrumental and they weren't specific +expertise that they brought to the + + align:start position:0% +expertise that they brought to the + + + align:start position:0% +expertise that they brought to the +project also but there was there was + + align:start position:0% +project also but there was there was + + + align:start position:0% +project also but there was there was +relative freedom for a lot of the + + align:start position:0% +relative freedom for a lot of the + + + align:start position:0% +relative freedom for a lot of the +scientists involved in denatech so one + + align:start position:0% +scientists involved in denatech so one + + + align:start position:0% +scientists involved in denatech so one +of the things that Swanson did to get + + align:start position:0% +of the things that Swanson did to get + + + align:start position:0% +of the things that Swanson did to get +people on board especially David Coto + + align:start position:0% +people on board especially David Coto + + + align:start position:0% +people on board especially David Coto +he said that they could still have the + + align:start position:0% +he said that they could still have the + + + align:start position:0% +he said that they could still have the +freedom to publish under their own name + + align:start position:0% +freedom to publish under their own name + + + align:start position:0% +freedom to publish under their own name +even though they were contracted to + + align:start position:0% +even though they were contracted to + + + align:start position:0% +even though they were contracted to +genitive so that was a real incentive + + align:start position:0% +genitive so that was a real incentive + + + align:start position:0% +genitive so that was a real incentive +for people to join them and lastly there + + align:start position:0% +for people to join them and lastly there + + + align:start position:0% +for people to join them and lastly there +was a really casual environment in the + + align:start position:0% +was a really casual environment in the + + + align:start position:0% +was a really casual environment in the +office teacher attire and you know there + + align:start position:0% +office teacher attire and you know there + + + align:start position:0% +office teacher attire and you know there +wasn't any you know strict rules or a + + align:start position:0% +wasn't any you know strict rules or a + + + align:start position:0% +wasn't any you know strict rules or a +sense of top-down management so um some + + align:start position:0% +sense of top-down management so um some + + + align:start position:0% +sense of top-down management so um some +other dynamics that I think they're + + align:start position:0% +other dynamics that I think they're + + + align:start position:0% +other dynamics that I think they're +important this was an interesting case + + align:start position:0% +important this was an interesting case + + + align:start position:0% +important this was an interesting case +of a great group because it came at a + + align:start position:0% +of a great group because it came at a + + + align:start position:0% +of a great group because it came at a +time when there was kind of a changing + + align:start position:0% +time when there was kind of a changing + + + align:start position:0% +time when there was kind of a changing +relationship between science and + + align:start position:0% +relationship between science and + + + align:start position:0% +relationship between science and +business and academia and the commercial + + align:start position:0% +business and academia and the commercial + + + align:start position:0% +business and academia and the commercial +sector and Boyer's journey was pretty + + align:start position:0% +sector and Boyer's journey was pretty + + + align:start position:0% +sector and Boyer's journey was pretty +interesting he started out firmly in + + align:start position:0% +interesting he started out firmly in + + + align:start position:0% +interesting he started out firmly in +academia but he chose to look beyond + + align:start position:0% +academia but he chose to look beyond + + + align:start position:0% +academia but he chose to look beyond +that his words like I said it with his + + align:start position:0% +that his words like I said it with his + + + align:start position:0% +that his words like I said it with his +words at the initial meeting with + + align:start position:0% +words at the initial meeting with + + + align:start position:0% +words at the initial meeting with +Swanson about wanting to see the real + + align:start position:0% +Swanson about wanting to see the real + + + align:start position:0% +Swanson about wanting to see the real +practical benefits of his work kind of + + align:start position:0% +practical benefits of his work kind of + + + align:start position:0% +practical benefits of his work kind of +carry them carried the whole team + + align:start position:0% +carry them carried the whole team + + + align:start position:0% +carry them carried the whole team +throughout but you know the flip side of + + align:start position:0% +throughout but you know the flip side of + + + align:start position:0% +throughout but you know the flip side of +that was that in the early history of + + align:start position:0% +that was that in the early history of + + + align:start position:0% +that was that in the early history of +Genentech he was a target for academic + + align:start position:0% +Genentech he was a target for academic + + + align:start position:0% +Genentech he was a target for academic +scientists who dismissed the idea that + + align:start position:0% +scientists who dismissed the idea that + + + align:start position:0% +scientists who dismissed the idea that +parking signs would ever be able to + + align:start position:0% +parking signs would ever be able to + + + align:start position:0% +parking signs would ever be able to +achieve the kind of things that they + + align:start position:0% +achieve the kind of things that they + + + align:start position:0% +achieve the kind of things that they +would be able to achieve and his move to + + align:start position:0% +would be able to achieve and his move to + + + align:start position:0% +would be able to achieve and his move to +commercialization really drew the + + align:start position:0% +commercialization really drew the + + + align:start position:0% +commercialization really drew the +animosity of academia because he was one + + align:start position:0% +animosity of academia because he was one + + + align:start position:0% +animosity of academia because he was one +of the first of many scientists at the + + align:start position:0% +of the first of many scientists at the + + + align:start position:0% +of the first of many scientists at the +frontier of molecular biology who were + + align:start position:0% +frontier of molecular biology who were + + + align:start position:0% +frontier of molecular biology who were +who sought to capitalize on the + + align:start position:0% +who sought to capitalize on the + + + align:start position:0% +who sought to capitalize on the +commercial opportunities + + align:start position:0% + + + + align:start position:0% + +and one of Swanson's and boys to some + + align:start position:0% +and one of Swanson's and boys to some + + + align:start position:0% +and one of Swanson's and boys to some +extent strength was their ability to + + align:start position:0% +extent strength was their ability to + + + align:start position:0% +extent strength was their ability to +recognize the exact moment in in the in + + align:start position:0% +recognize the exact moment in in the in + + + align:start position:0% +recognize the exact moment in in the in +basic research in molecular + + align:start position:0% +basic research in molecular + + + align:start position:0% +basic research in molecular +biotechnology that was most beneficial + + align:start position:0% +biotechnology that was most beneficial + + + align:start position:0% +biotechnology that was most beneficial +to open up to it to open it up to a + + align:start position:0% +to open up to it to open it up to a + + + align:start position:0% +to open up to it to open it up to a +commercial endeavor so they were able to + + align:start position:0% +commercial endeavor so they were able to + + + align:start position:0% +commercial endeavor so they were able to +combine an extensive knowledge of the + + align:start position:0% +combine an extensive knowledge of the + + + align:start position:0% +combine an extensive knowledge of the +science moment they were trying to do + + align:start position:0% +science moment they were trying to do + + + align:start position:0% +science moment they were trying to do +and also the business acumen needed to + + align:start position:0% +and also the business acumen needed to + + + align:start position:0% +and also the business acumen needed to +move it forward and this really set them + + align:start position:0% +move it forward and this really set them + + + align:start position:0% +move it forward and this really set them +apart from other big drunk drug + + align:start position:0% +apart from other big drunk drug + + + align:start position:0% +apart from other big drunk drug +companies at the time and I think + + align:start position:0% +companies at the time and I think + + + align:start position:0% +companies at the time and I think +ultimately contributed to their great + + align:start position:0% +ultimately contributed to their great + + + align:start position:0% +ultimately contributed to their great +success as well yeah so this is a quote + + align:start position:0% +success as well yeah so this is a quote + + + align:start position:0% +success as well yeah so this is a quote +about Swanson who was really kind of one + + align:start position:0% +about Swanson who was really kind of one + + + align:start position:0% +about Swanson who was really kind of one +of the first figures who was able to + + align:start position:0% +of the first figures who was able to + + + align:start position:0% +of the first figures who was able to +really bridge that the partnership + + align:start position:0% +really bridge that the partnership + + + align:start position:0% +really bridge that the partnership +between science and business so in a way + + align:start position:0% +between science and business so in a way + + + align:start position:0% +between science and business so in a way +you can kind of think of him as like an + + align:start position:0% +you can kind of think of him as like an + + + align:start position:0% +you can kind of think of him as like an +advocate before the scientists that he + + align:start position:0% +advocate before the scientists that he + + + align:start position:0% +advocate before the scientists that he +was representing and people like Jenna + + align:start position:0% +was representing and people like Jenna + + + align:start position:0% +was representing and people like Jenna +fact who were looking to really advance + + align:start position:0% +fact who were looking to really advance + + + align:start position:0% +fact who were looking to really advance +in this field that was quite new so I + + align:start position:0% +in this field that was quite new so I + + + align:start position:0% +in this field that was quite new so I +guess one of going into sort of + + align:start position:0% +guess one of going into sort of + + + align:start position:0% +guess one of going into sort of +discussion questions one of my main + + align:start position:0% +discussion questions one of my main + + + align:start position:0% +discussion questions one of my main +questions was did the relative newness + + align:start position:0% +questions was did the relative newness + + + align:start position:0% +questions was did the relative newness +of this field in this industry really + + align:start position:0% +of this field in this industry really + + + align:start position:0% +of this field in this industry really +help them I mean did that offer their + + align:start position:0% +help them I mean did that offer their + + + align:start position:0% +help them I mean did that offer their +opportunities to Swanson to worry that + + align:start position:0% +opportunities to Swanson to worry that + + + align:start position:0% +opportunities to Swanson to worry that +maybe more established industry or field + + align:start position:0% +maybe more established industry or field + + + align:start position:0% +maybe more established industry or field +would not have did that allow so I'm + + align:start position:0% +would not have did that allow so I'm + + + align:start position:0% +would not have did that allow so I'm +gonna put that on hold for just a second + + align:start position:0% +gonna put that on hold for just a second + + + align:start position:0% +gonna put that on hold for just a second +because through a couple of kind of + + align:start position:0% +because through a couple of kind of + + + align:start position:0% +because through a couple of kind of +framing points out but that's I think + + align:start position:0% +framing points out but that's I think + + + align:start position:0% +framing points out but that's I think +that's a key question and I'll lead up + + align:start position:0% +that's a key question and I'll lead up + + + align:start position:0% +that's a key question and I'll lead up +to that to them this is the first + + align:start position:0% +to that to them this is the first + + + align:start position:0% +to that to them this is the first +biotech right this creates the model and + + align:start position:0% +biotech right this creates the model and + + + align:start position:0% +biotech right this creates the model and +you know as you point out this + + align:start position:0% +you know as you point out this + + + align:start position:0% +you know as you point out this +combination of Boyer and Swanson is a + + align:start position:0% +combination of Boyer and Swanson is a + + + align:start position:0% +combination of Boyer and Swanson is a +fascinating combination because they are + + align:start position:0% +fascinating combination because they are + + + align:start position:0% +fascinating combination because they are +as you put it able to kind of bridge + + align:start position:0% +as you put it able to kind of bridge + + + align:start position:0% +as you put it able to kind of bridge +this divide between business and science + + align:start position:0% +this divide between business and science + + + align:start position:0% +this divide between business and science +and that is the inherent you know + + align:start position:0% +and that is the inherent you know + + + align:start position:0% +and that is the inherent you know +brilliance of the biotech model and + + align:start position:0% +brilliance of the biotech model and + + + align:start position:0% +brilliance of the biotech model and +these folks really figure out how to do + + align:start position:0% +these folks really figure out how to do + + + align:start position:0% +these folks really figure out how to do +it and genatech to this day is an + + align:start position:0% +it and genatech to this day is an + + + align:start position:0% +it and genatech to this day is an +extremely successful company so it has + + align:start position:0% +extremely successful company so it has + + + align:start position:0% +extremely successful company so it has +been able to keep on that innovation + + align:start position:0% +been able to keep on that innovation + + + align:start position:0% +been able to keep on that innovation +pathway which means to the culture that + + align:start position:0% +pathway which means to the culture that + + + align:start position:0% +pathway which means to the culture that +they set up here has been able to keep + + align:start position:0% +they set up here has been able to keep + + + align:start position:0% +they set up here has been able to keep +you know innovation occurring on a kind + + align:start position:0% +you know innovation occurring on a kind + + + align:start position:0% +you know innovation occurring on a kind +of ongoing basis and some of the points + + align:start position:0% +of ongoing basis and some of the points + + + align:start position:0% +of ongoing basis and some of the points +you made sand them just to emphasize + + align:start position:0% +you made sand them just to emphasize + + + align:start position:0% +you made sand them just to emphasize +some of the points you made the fact + + align:start position:0% +some of the points you made the fact + + + align:start position:0% +some of the points you made the fact +that Boyer and Swanson allowed their + + align:start position:0% +that Boyer and Swanson allowed their + + + align:start position:0% +that Boyer and Swanson allowed their +researchers to do their own publishing + + align:start position:0% +researchers to do their own publishing + + + align:start position:0% +researchers to do their own publishing +right that they didn't treat what they + + align:start position:0% +right that they didn't treat what they + + + align:start position:0% +right that they didn't treat what they +were working on is a complete trade + + align:start position:0% +were working on is a complete trade + + + align:start position:0% +were working on is a complete trade +secret that was a huge enabler in + + align:start position:0% +secret that was a huge enabler in + + + align:start position:0% +secret that was a huge enabler in +enabling the academic community to kind + + align:start position:0% +enabling the academic community to kind + + + align:start position:0% +enabling the academic community to kind +of enter into these biotech so in other + + align:start position:0% +of enter into these biotech so in other + + + align:start position:0% +of enter into these biotech so in other +words their academic role was going to + + align:start position:0% +words their academic role was going to + + + align:start position:0% +words their academic role was going to +be respected their role as researchers + + align:start position:0% +be respected their role as researchers + + + align:start position:0% +be respected their role as researchers +and scientists and contributing to + + align:start position:0% +and scientists and contributing to + + + align:start position:0% +and scientists and contributing to +general knowledge was going to have + + align:start position:0% +general knowledge was going to have + + + align:start position:0% +general knowledge was going to have +respect it here and that created a rule + + align:start position:0% +respect it here and that created a rule + + + align:start position:0% +respect it here and that created a rule +in this biotech that you know prevails + + align:start position:0% +in this biotech that you know prevails + + + align:start position:0% +in this biotech that you know prevails +this to this day and yet it very much + + align:start position:0% +this to this day and yet it very much + + + align:start position:0% +this to this day and yet it very much +influenced the kind of model but the + + align:start position:0% +influenced the kind of model but the + + + align:start position:0% +influenced the kind of model but the +ability so in the biotech model and + + align:start position:0% +ability so in the biotech model and + + + align:start position:0% +ability so in the biotech model and +Swenson and Swanson and and and Boyer + + align:start position:0% +Swenson and Swanson and and and Boyer + + + align:start position:0% +Swenson and Swanson and and and Boyer +pioneer this they create this revolving + + align:start position:0% +pioneer this they create this revolving + + + align:start position:0% +pioneer this they create this revolving +door capability so in other words + + align:start position:0% +door capability so in other words + + + align:start position:0% +door capability so in other words +scientists at universities now in the + + align:start position:0% +scientists at universities now in the + + + align:start position:0% +scientists at universities now in the +United States that work in in life + + align:start position:0% +United States that work in in life + + + align:start position:0% +United States that work in in life +science areas and related areas are able + + align:start position:0% +science areas and related areas are able + + + align:start position:0% +science areas and related areas are able +to have careers whether in the Academy + + align:start position:0% +to have careers whether in the Academy + + + align:start position:0% +to have careers whether in the Academy +they moved to a biotech you know as a + + align:start position:0% +they moved to a biotech you know as a + + + align:start position:0% +they moved to a biotech you know as a +scientist for a period of time they can + + align:start position:0% +scientist for a period of time they can + + + align:start position:0% +scientist for a period of time they can +move back to the Academy right taking + + align:start position:0% +move back to the Academy right taking + + + align:start position:0% +move back to the Academy right taking +their advances with them in other words + + align:start position:0% +their advances with them in other words + + + align:start position:0% +their advances with them in other words +they can move between these sectors so + + align:start position:0% +they can move between these sectors so + + + align:start position:0% +they can move between these sectors so +there was in European science and + + align:start position:0% +there was in European science and + + + align:start position:0% +there was in European science and +historical Upstairs Downstairs treatment + + align:start position:0% +historical Upstairs Downstairs treatment + + + align:start position:0% +historical Upstairs Downstairs treatment +right the academic scientists thought + + align:start position:0% +right the academic scientists thought + + + align:start position:0% +right the academic scientists thought +they were in curiosity-driven basic + + align:start position:0% +they were in curiosity-driven basic + + + align:start position:0% +they were in curiosity-driven basic +research and should have nothing to do + + align:start position:0% +research and should have nothing to do + + + align:start position:0% +research and should have nothing to do +with the kind of ugliness and kind of + + align:start position:0% +with the kind of ugliness and kind of + + + align:start position:0% +with the kind of ugliness and kind of +downstairs of commercialization of + + align:start position:0% +downstairs of commercialization of + + + align:start position:0% +downstairs of commercialization of +products and that these worlds ought to + + align:start position:0% +products and that these worlds ought to + + + align:start position:0% +products and that these worlds ought to +be kept separate and biotech is the + + align:start position:0% +be kept separate and biotech is the + + + align:start position:0% +be kept separate and biotech is the +first really serious attempt in the in + + align:start position:0% +first really serious attempt in the in + + + align:start position:0% +first really serious attempt in the in +the Academy in America to kind of bridge + + align:start position:0% +the Academy in America to kind of bridge + + + align:start position:0% +the Academy in America to kind of bridge +these worlds effectively and they do + + align:start position:0% +these worlds effectively and they do + + + align:start position:0% +these worlds effectively and they do +brilliantly and part of it is as you + + align:start position:0% +brilliantly and part of it is as you + + + align:start position:0% +brilliantly and part of it is as you +point out you know Swanson is a + + align:start position:0% +point out you know Swanson is a + + + align:start position:0% +point out you know Swanson is a +chemistry major at MIT so he is not + + align:start position:0% +chemistry major at MIT so he is not + + + align:start position:0% +chemistry major at MIT so he is not +afraid of science just as you suggest + + align:start position:0% +afraid of science just as you suggest + + + align:start position:0% +afraid of science just as you suggest +that he understands what it is he has he + + align:start position:0% +that he understands what it is he has he + + + align:start position:0% +that he understands what it is he has he +has the ability to be in the room + + align:start position:0% +has the ability to be in the room + + + align:start position:0% +has the ability to be in the room +with these academic scientists and be in + + align:start position:0% +with these academic scientists and be in + + + align:start position:0% +with these academic scientists and be in +the game but he also comes to this with + + align:start position:0% +the game but he also comes to this with + + + align:start position:0% +the game but he also comes to this with +early venture capital experience so he + + align:start position:0% +early venture capital experience so he + + + align:start position:0% +early venture capital experience so he +first goes to work on Sand Hill Road you + + align:start position:0% +first goes to work on Sand Hill Road you + + + align:start position:0% +first goes to work on Sand Hill Road you +know out outside outside in silicon + + align:start position:0% +know out outside outside in silicon + + + align:start position:0% +know out outside outside in silicon +valley outside Stanford and they're only + + align:start position:0% +valley outside Stanford and they're only + + + align:start position:0% +valley outside Stanford and they're only +in Reston to doing IT they have no idea + + align:start position:0% +in Reston to doing IT they have no idea + + + align:start position:0% +in Reston to doing IT they have no idea +about this biotech stuff so he has to + + align:start position:0% +about this biotech stuff so he has to + + + align:start position:0% +about this biotech stuff so he has to +leave this major event early venture + + align:start position:0% +leave this major event early venture + + + align:start position:0% +leave this major event early venture +capital for him that he's with and + + align:start position:0% +capital for him that he's with and + + + align:start position:0% +capital for him that he's with and +essentially starve you know eat hot dogs + + align:start position:0% +essentially starve you know eat hot dogs + + + align:start position:0% +essentially starve you know eat hot dogs +for months at a time as he tries to + + align:start position:0% +for months at a time as he tries to + + + align:start position:0% +for months at a time as he tries to +figure out how is he going to work in + + align:start position:0% +figure out how is he going to work in + + + align:start position:0% +figure out how is he going to work in +this biotech area and famously he as + + align:start position:0% +this biotech area and famously he as + + + align:start position:0% +this biotech area and famously he as +Sonam suggested famously he starts cold + + align:start position:0% +Sonam suggested famously he starts cold + + + align:start position:0% +Sonam suggested famously he starts cold +calling he has this idea that + + align:start position:0% +calling he has this idea that + + + align:start position:0% +calling he has this idea that +bioengineering is going to be this + + align:start position:0% +bioengineering is going to be this + + + align:start position:0% +bioengineering is going to be this +incredibly creative new field he's aware + + align:start position:0% +incredibly creative new field he's aware + + + align:start position:0% +incredibly creative new field he's aware +of it from his own training so he starts + + align:start position:0% +of it from his own training so he starts + + + align:start position:0% +of it from his own training so he starts +cold calling scientists that are working + + align:start position:0% +cold calling scientists that are working + + + align:start position:0% +cold calling scientists that are working +in this bioengineering field he only has + + align:start position:0% +in this bioengineering field he only has + + + align:start position:0% +in this bioengineering field he only has +to get to the bees right to Boyer and + + align:start position:0% +to get to the bees right to Boyer and + + + align:start position:0% +to get to the bees right to Boyer and +then they have this famous meeting at + + align:start position:0% +then they have this famous meeting at + + + align:start position:0% +then they have this famous meeting at +Churchill's pub where they actually so + + align:start position:0% +Churchill's pub where they actually so + + + align:start position:0% +Churchill's pub where they actually so +much hit it off exactly as Sonam + + align:start position:0% +much hit it off exactly as Sonam + + + align:start position:0% +much hit it off exactly as Sonam +described Boyer is concerned that if he + + align:start position:0% +described Boyer is concerned that if he + + + align:start position:0% +described Boyer is concerned that if he +just stays in the Academy nothing he + + align:start position:0% +just stays in the Academy nothing he + + + align:start position:0% +just stays in the Academy nothing he +works on is ever gonna get out right and + + align:start position:0% +works on is ever gonna get out right and + + + align:start position:0% +works on is ever gonna get out right and +he wants to get his stuff out he truly + + align:start position:0% +he wants to get his stuff out he truly + + + align:start position:0% +he wants to get his stuff out he truly +believes this this is not like this he + + align:start position:0% +believes this this is not like this he + + + align:start position:0% +believes this this is not like this he +is not out to get rich here he is really + + align:start position:0% +is not out to get rich here he is really + + + align:start position:0% +is not out to get rich here he is really +out to get to save people and get the + + align:start position:0% +out to get to save people and get the + + + align:start position:0% +out to get to save people and get the +technology out the door so in there's a + + align:start position:0% +technology out the door so in there's a + + + align:start position:0% +technology out the door so in there's a +statue in front of Genentech to this day + + align:start position:0% +statue in front of Genentech to this day + + + align:start position:0% +statue in front of Genentech to this day +that pictures Boyer and Swanson sitting + + align:start position:0% +that pictures Boyer and Swanson sitting + + + align:start position:0% +that pictures Boyer and Swanson sitting +at the bar each pointing the hundred + + align:start position:0% +at the bar each pointing the hundred + + + align:start position:0% +at the bar each pointing the hundred +dollars down on the table as they toast + + align:start position:0% +dollars down on the table as they toast + + + align:start position:0% +dollars down on the table as they toast +each other with beers that that's what + + align:start position:0% +each other with beers that that's what + + + align:start position:0% +each other with beers that that's what +you see when you drive in and see the + + align:start position:0% +you see when you drive in and see the + + + align:start position:0% +you see when you drive in and see the +company headquarters and genatech and + + align:start position:0% +company headquarters and genatech and + + + align:start position:0% +company headquarters and genatech and +that's symbolic think of what's + + align:start position:0% +that's symbolic think of what's + + + align:start position:0% +that's symbolic think of what's +happening here + + align:start position:0% +happening here + + + align:start position:0% +happening here +these folks figure out how to make a + + align:start position:0% +these folks figure out how to make a + + + align:start position:0% +these folks figure out how to make a +really workable marriage between + + align:start position:0% +really workable marriage between + + + align:start position:0% +really workable marriage between +business and science that's you know + + align:start position:0% +business and science that's you know + + + align:start position:0% +business and science that's you know +remarkably productive on both sides of + + align:start position:0% +remarkably productive on both sides of + + + align:start position:0% +remarkably productive on both sides of +the world Boyer is totally ostracized + + align:start position:0% +the world Boyer is totally ostracized + + + align:start position:0% +the world Boyer is totally ostracized +for doing this right + + align:start position:0% +for doing this right + + + align:start position:0% +for doing this right +he faces tremendous recrimination at + + align:start position:0% +he faces tremendous recrimination at + + + align:start position:0% +he faces tremendous recrimination at +UCSF + + align:start position:0% +UCSF + + + align:start position:0% +UCSF +for having gone this commercial roof and + + align:start position:0% +for having gone this commercial roof and + + + align:start position:0% +for having gone this commercial roof and +it's only when they come up with these + + align:start position:0% +it's only when they come up with these + + + align:start position:0% +it's only when they come up with these +stunning successes that the scientific + + align:start position:0% +stunning successes that the scientific + + + align:start position:0% +stunning successes that the scientific +community really has to rethink the kind + + align:start position:0% +community really has to rethink the kind + + + align:start position:0% +community really has to rethink the kind +of way that it went after him so this + + align:start position:0% +of way that it went after him so this + + + align:start position:0% +of way that it went after him so this +was not easy for either of these players + + align:start position:0% +was not easy for either of these players + + + align:start position:0% +was not easy for either of these players +but it's really it's a fascinating + + align:start position:0% +but it's really it's a fascinating + + + align:start position:0% +but it's really it's a fascinating +moment and our way creates a culture + + align:start position:0% +moment and our way creates a culture + + + align:start position:0% +moment and our way creates a culture +that to this day kind of still dominates + + align:start position:0% +that to this day kind of still dominates + + + align:start position:0% +that to this day kind of still dominates +that whole sector that's a fair summary + + align:start position:0% +that whole sector that's a fair summary + + + align:start position:0% +that whole sector that's a fair summary +now let's come back to your great + + align:start position:0% +now let's come back to your great + + + align:start position:0% +now let's come back to your great +question why don't you just pose it + + align:start position:0% +question why don't you just pose it + + + align:start position:0% +question why don't you just pose it +again quickly cinnamon wondering what's + + align:start position:0% +again quickly cinnamon wondering what's + + + align:start position:0% +again quickly cinnamon wondering what's +there you had mentioned the ability to + + align:start position:0% +there you had mentioned the ability to + + + align:start position:0% +there you had mentioned the ability to +publish under their own name was there + + align:start position:0% +publish under their own name was there + + + align:start position:0% +publish under their own name was there +anything else that might have spurred + + align:start position:0% +anything else that might have spurred + + + align:start position:0% +anything else that might have spurred +their success or that might have spurred + + align:start position:0% +their success or that might have spurred + + + align:start position:0% +their success or that might have spurred +the success of this marriage as you put + + align:start position:0% +the success of this marriage as you put + + + align:start position:0% +the success of this marriage as you put +it between I could even have business + + align:start position:0% +it between I could even have business + + + align:start position:0% +it between I could even have business +well that's recruitment tool in other + + align:start position:0% +well that's recruitment tool in other + + + align:start position:0% +well that's recruitment tool in other +words if you leave academic research you + + align:start position:0% +words if you leave academic research you + + + align:start position:0% +words if you leave academic research you +know University labs and come to work + + align:start position:0% +know University labs and come to work + + + align:start position:0% +know University labs and come to work +for Genentech you don't have to abandon + + align:start position:0% +for Genentech you don't have to abandon + + + align:start position:0% +for Genentech you don't have to abandon +your academic career you can still keep + + align:start position:0% +your academic career you can still keep + + + align:start position:0% +your academic career you can still keep +doing your research work and building + + align:start position:0% +doing your research work and building + + + align:start position:0% +doing your research work and building +your research reputation while you're + + align:start position:0% +your research reputation while you're + + + align:start position:0% +your research reputation while you're +working at a company and that's what + + align:start position:0% +working at a company and that's what + + + align:start position:0% +working at a company and that's what +that enabled so what enabled academic + + align:start position:0% +that enabled so what enabled academic + + + align:start position:0% +that enabled so what enabled academic +researchers to feel that they weren't + + align:start position:0% +researchers to feel that they weren't + + + align:start position:0% +researchers to feel that they weren't +leaving the universe that they had that + + align:start position:0% +leaving the universe that they had that + + + align:start position:0% +leaving the universe that they had that +had nurtured them they could continue + + align:start position:0% +had nurtured them they could continue + + + align:start position:0% +had nurtured them they could continue +doing terrific academic work as well as + + align:start position:0% +doing terrific academic work as well as + + + align:start position:0% +doing terrific academic work as well as +practical work in this kind of company + + align:start position:0% +practical work in this kind of company + + + align:start position:0% +practical work in this kind of company +setting and that was very reassuring and + + align:start position:0% +setting and that was very reassuring and + + + align:start position:0% +setting and that was very reassuring and +it was a great it was a great it broke + + align:start position:0% +it was a great it was a great it broke + + + align:start position:0% +it was a great it was a great it broke +down a whole divide between the worlds + + align:start position:0% +down a whole divide between the worlds + + + align:start position:0% +down a whole divide between the worlds +because previously in in pharmaceutical + + align:start position:0% +because previously in in pharmaceutical + + + align:start position:0% +because previously in in pharmaceutical +companies everything was secret right + + align:start position:0% +companies everything was secret right + + + align:start position:0% +companies everything was secret right +everything was treated as a trade secret + + align:start position:0% +everything was treated as a trade secret + + + align:start position:0% +everything was treated as a trade secret +so there was no outside discussion + + align:start position:0% +so there was no outside discussion + + + align:start position:0% +so there was no outside discussion +allowed until patents occurred this + + align:start position:0% +allowed until patents occurred this + + + align:start position:0% +allowed until patents occurred this +really changed that culture but soon I + + align:start position:0% +really changed that culture but soon I + + + align:start position:0% +really changed that culture but soon I +restate your question because it was a + + align:start position:0% +restate your question because it was a + + + align:start position:0% +restate your question because it was a +very good one let's go back to it yeah + + align:start position:0% +very good one let's go back to it yeah + + + align:start position:0% +very good one let's go back to it yeah +so my question was do you think that the + + align:start position:0% +so my question was do you think that the + + + align:start position:0% +so my question was do you think that the +the fact that the skill and the field + + align:start position:0% +the fact that the skill and the field + + + align:start position:0% +the fact that the skill and the field +this field was so new and so starting + + align:start position:0% +this field was so new and so starting + + + align:start position:0% +this field was so new and so starting +you know very few years before that we + + align:start position:0% +you know very few years before that we + + + align:start position:0% +you know very few years before that we +help them or afforded them certain + + align:start position:0% +help them or afforded them certain + + + align:start position:0% +help them or afforded them certain +opportunities that they might not have + + align:start position:0% +opportunities that they might not have + + + align:start position:0% +opportunities that they might not have +been able to have any more establish + + align:start position:0% +been able to have any more establish + + + align:start position:0% +been able to have any more establish +entrenched the older industry absolutely + + align:start position:0% +entrenched the older industry absolutely + + + align:start position:0% +entrenched the older industry absolutely +because there was a previous + + align:start position:0% +because there was a previous + + + align:start position:0% +because there was a previous +infrastructure there was no + + align:start position:0% +infrastructure there was no + + + align:start position:0% +infrastructure there was no +establishment to fight that was just the + + align:start position:0% +establishment to fight that was just the + + + align:start position:0% +establishment to fight that was just the +scientific challenge and then trying to + + align:start position:0% +scientific challenge and then trying to + + + align:start position:0% +scientific challenge and then trying to +commercialize it of course I mean there + + align:start position:0% +commercialize it of course I mean there + + + align:start position:0% +commercialize it of course I mean there +were other there were other companies + + align:start position:0% +were other there were other companies + + + align:start position:0% +were other there were other companies +that were trying to do these things but + + align:start position:0% +that were trying to do these things but + + + align:start position:0% +that were trying to do these things but +because it wasn't as established its I'm + + align:start position:0% +because it wasn't as established its I'm + + + align:start position:0% +because it wasn't as established its I'm +no coal or the railroad industries and + + align:start position:0% +no coal or the railroad industries and + + + align:start position:0% +no coal or the railroad industries and +like that it it's I think it certainly + + align:start position:0% +like that it it's I think it certainly + + + align:start position:0% +like that it it's I think it certainly +made things a lot easier + + align:start position:0% +made things a lot easier + + + align:start position:0% +made things a lot easier +the market was a lot more fluid and they + + align:start position:0% +the market was a lot more fluid and they + + + align:start position:0% +the market was a lot more fluid and they +had a lot more areas to expand into I + + align:start position:0% +had a lot more areas to expand into I + + + align:start position:0% +had a lot more areas to expand into I +think not only that sorry there is also + + align:start position:0% +think not only that sorry there is also + + + align:start position:0% +think not only that sorry there is also +a lot more room for error especially as + + align:start position:0% +a lot more room for error especially as + + + align:start position:0% +a lot more room for error especially as +they're getting started initially + + align:start position:0% +they're getting started initially + + + align:start position:0% +they're getting started initially +they're able to like experiment they + + align:start position:0% +they're able to like experiment they + + + align:start position:0% +they're able to like experiment they +more leeway in the way they can mark it + + align:start position:0% +more leeway in the way they can mark it + + + align:start position:0% +more leeway in the way they can mark it +and present their product because there + + align:start position:0% +and present their product because there + + + align:start position:0% +and present their product because there +is no established market doesn't mean if + + align:start position:0% +is no established market doesn't mean if + + + align:start position:0% +is no established market doesn't mean if +someone could share maybe what they + + align:start position:0% +someone could share maybe what they + + + align:start position:0% +someone could share maybe what they +thought the regulatory challenges that + + align:start position:0% +thought the regulatory challenges that + + + align:start position:0% +thought the regulatory challenges that +they didn't face were I think it was + + align:start position:0% +they didn't face were I think it was + + + align:start position:0% +they didn't face were I think it was +mentioned that they pretty much use the + + align:start position:0% +mentioned that they pretty much use the + + + align:start position:0% +mentioned that they pretty much use the +ability to use synthetic DNA in order to + + align:start position:0% +ability to use synthetic DNA in order to + + + align:start position:0% +ability to use synthetic DNA in order to +get over a lot of regulations also is + + align:start position:0% +get over a lot of regulations also is + + + align:start position:0% +get over a lot of regulations also is +relatively early nowadays it's a lot + + align:start position:0% +relatively early nowadays it's a lot + + + align:start position:0% +relatively early nowadays it's a lot +harder I didn't like the price point to + + align:start position:0% +harder I didn't like the price point to + + + align:start position:0% +harder I didn't like the price point to +make a drug it's over a billion back + + align:start position:0% +make a drug it's over a billion back + + + align:start position:0% +make a drug it's over a billion back +then I really don't know what it was so + + align:start position:0% +then I really don't know what it was so + + + align:start position:0% +then I really don't know what it was so +really was a great opportunity also + + align:start position:0% +really was a great opportunity also + + + align:start position:0% +really was a great opportunity also +their investors were kleiner perkins + + align:start position:0% +their investors were kleiner perkins + + + align:start position:0% +their investors were kleiner perkins +also one of those purchases attended + + align:start position:0% +also one of those purchases attended + + + align:start position:0% +also one of those purchases attended +swanson had originally worked for + + align:start position:0% +swanson had originally worked for + + + align:start position:0% +swanson had originally worked for +had to leave because they didn't want to + + align:start position:0% +had to leave because they didn't want to + + + align:start position:0% +had to leave because they didn't want to +do biotech but he went back to them with + + align:start position:0% +do biotech but he went back to them with + + + align:start position:0% +do biotech but he went back to them with +this advance and they you know gave him + + align:start position:0% +this advance and they you know gave him + + + align:start position:0% +this advance and they you know gave him +some money but the investors were + + align:start position:0% +some money but the investors were + + + align:start position:0% +some money but the investors were +adequate and what about Chris do you + + align:start position:0% +adequate and what about Chris do you + + + align:start position:0% +adequate and what about Chris do you +have any thoughts on the regulatory + + align:start position:0% +have any thoughts on the regulatory + + + align:start position:0% +have any thoughts on the regulatory +challenge yeah so definitely using + + align:start position:0% +challenge yeah so definitely using + + + align:start position:0% +challenge yeah so definitely using +synthetic kinds of molecules in an + + align:start position:0% +synthetic kinds of molecules in an + + + align:start position:0% +synthetic kinds of molecules in an +approach definitely helps because you + + align:start position:0% +approach definitely helps because you + + + align:start position:0% +approach definitely helps because you +can surpass that whole and clinical + + align:start position:0% +can surpass that whole and clinical + + + align:start position:0% +can surpass that whole and clinical +challenge which not only is like hard to + + align:start position:0% +challenge which not only is like hard to + + + align:start position:0% +challenge which not only is like hard to +pass but it also takes a long time right + + align:start position:0% +pass but it also takes a long time right + + + align:start position:0% +pass but it also takes a long time right +especially they were mentioning there's + + align:start position:0% +especially they were mentioning there's + + + align:start position:0% +especially they were mentioning there's +a real time crunch a lot of groups were + + align:start position:0% +a real time crunch a lot of groups were + + + align:start position:0% +a real time crunch a lot of groups were +doing this that's kind of approaching + + align:start position:0% +doing this that's kind of approaching + + + align:start position:0% +doing this that's kind of approaching +research in this field they really had + + align:start position:0% +research in this field they really had + + + align:start position:0% +research in this field they really had +to be the first ones out there so they + + align:start position:0% +to be the first ones out there so they + + + align:start position:0% +to be the first ones out there so they +could establish themselves as leader and + + align:start position:0% +could establish themselves as leader and + + + align:start position:0% +could establish themselves as leader and +the real innovators and kind of this new + + align:start position:0% +the real innovators and kind of this new + + + align:start position:0% +the real innovators and kind of this new +biotech field so I think their approach + + align:start position:0% +biotech field so I think their approach + + + align:start position:0% +biotech field so I think their approach +is smart right I mean this is a moment + + align:start position:0% +is smart right I mean this is a moment + + + align:start position:0% +is smart right I mean this is a moment +where there's a deep concern that comes + + align:start position:0% +where there's a deep concern that comes + + + align:start position:0% +where there's a deep concern that comes +up from the public but also in the + + align:start position:0% +up from the public but also in the + + + align:start position:0% +up from the public but also in the +academic community itself about the + + align:start position:0% +academic community itself about the + + + align:start position:0% +academic community itself about the +implications of this genetic engineering + + align:start position:0% +implications of this genetic engineering + + + align:start position:0% +implications of this genetic engineering +right I mean that's what Genentech + + align:start position:0% +right I mean that's what Genentech + + + align:start position:0% +right I mean that's what Genentech +stands for genetic engineering right + + align:start position:0% +stands for genetic engineering right + + + align:start position:0% +stands for genetic engineering right +that's what they're all about and + + align:start position:0% +that's what they're all about and + + + align:start position:0% +that's what they're all about and +there's a major effort to put this whole + + align:start position:0% +there's a major effort to put this whole + + + align:start position:0% +there's a major effort to put this whole +movement on pause right and there is an + + align:start position:0% +movement on pause right and there is an + + + align:start position:0% +movement on pause right and there is an +outcry in the City Council that that in + + align:start position:0% +outcry in the City Council that that in + + + align:start position:0% +outcry in the City Council that that in +Cambridge here you know a wild hearing + + align:start position:0% +Cambridge here you know a wild hearing + + + align:start position:0% +Cambridge here you know a wild hearing +by the City Council trying to shut down + + align:start position:0% +by the City Council trying to shut down + + + align:start position:0% +by the City Council trying to shut down +related research at Harvard and MIT + + align:start position:0% +related research at Harvard and MIT + + + align:start position:0% +related research at Harvard and MIT +because they're very worried about the + + align:start position:0% +because they're very worried about the + + + align:start position:0% +because they're very worried about the +implications of what's going to be + + align:start position:0% +implications of what's going to be + + + align:start position:0% +implications of what's going to be +happening here so then there's an effort + + align:start position:0% +happening here so then there's an effort + + + align:start position:0% +happening here so then there's an effort +by the scientific community in this + + align:start position:0% +by the scientific community in this + + + align:start position:0% +by the scientific community in this +famous conference called simmilar out in + + align:start position:0% +famous conference called simmilar out in + + + align:start position:0% +famous conference called simmilar out in +California where the whole community + + align:start position:0% +California where the whole community + + + align:start position:0% +California where the whole community +comes together there and kind of really + + align:start position:0% +comes together there and kind of really + + + align:start position:0% +comes together there and kind of really +begins to work through the ethics but + + align:start position:0% +begins to work through the ethics but + + + align:start position:0% +begins to work through the ethics but +their principal competitor Wally Gilbert + + align:start position:0% +their principal competitor Wally Gilbert + + + align:start position:0% +their principal competitor Wally Gilbert +at Harvard is forced because of this + + align:start position:0% +at Harvard is forced because of this + + + align:start position:0% +at Harvard is forced because of this +limit on genetic engineering the ability + + align:start position:0% +limit on genetic engineering the ability + + + align:start position:0% +limit on genetic engineering the ability +to use genetic DNA he has to go to + + align:start position:0% +to use genetic DNA he has to go to + + + align:start position:0% +to use genetic DNA he has to go to +England where they're still allowing + + align:start position:0% +England where they're still allowing + + + align:start position:0% +England where they're still allowing +that research and enlist the whole group + + align:start position:0% +that research and enlist the whole group + + + align:start position:0% +that research and enlist the whole group +of British scientists done to take his + + align:start position:0% +of British scientists done to take his + + + align:start position:0% +of British scientists done to take his +research but Swanson and Bohr get around + + align:start position:0% +research but Swanson and Bohr get around + + + align:start position:0% +research but Swanson and Bohr get around +that by using synthetic DNA and they + + align:start position:0% +that by using synthetic DNA and they + + + align:start position:0% +that by using synthetic DNA and they +avoid the whole outcry so it's a very + + align:start position:0% +avoid the whole outcry so it's a very + + + align:start position:0% +avoid the whole outcry so it's a very +interesting development it's slowed down + + align:start position:0% +interesting development it's slowed down + + + align:start position:0% +interesting development it's slowed down +they're competitors you know pretty + + align:start position:0% +they're competitors you know pretty + + + align:start position:0% +they're competitors you know pretty +considerably and Wally Gilbert was a + + align:start position:0% +considerably and Wally Gilbert was a + + + align:start position:0% +considerably and Wally Gilbert was a +great talent to be up against I mean a + + align:start position:0% +great talent to be up against I mean a + + + align:start position:0% +great talent to be up against I mean a +famous scientific leader and researcher + + align:start position:0% +famous scientific leader and researcher + + + align:start position:0% +famous scientific leader and researcher +I didn't do this reading or know that + + align:start position:0% +I didn't do this reading or know that + + + align:start position:0% +I didn't do this reading or know that +much about the genetic backgrounds at + + align:start position:0% +much about the genetic backgrounds at + + + align:start position:0% +much about the genetic backgrounds at +all but where the pharmaceutical + + align:start position:0% +all but where the pharmaceutical + + + align:start position:0% +all but where the pharmaceutical +companies at all their competitors are + + align:start position:0% +companies at all their competitors are + + + align:start position:0% +companies at all their competitors are +they very much so focused on just + + align:start position:0% +they very much so focused on just + + + align:start position:0% +they very much so focused on just +chemical stuff right I think boy I + + align:start position:0% +chemical stuff right I think boy I + + + align:start position:0% +chemical stuff right I think boy I +really came you saw that drawing with + + align:start position:0% +really came you saw that drawing with + + + align:start position:0% +really came you saw that drawing with +the pseudo that's a bacterial plasmid + + align:start position:0% +the pseudo that's a bacterial plasmid + + + align:start position:0% +the pseudo that's a bacterial plasmid +what's go back to this and then that + + align:start position:0% +what's go back to this and then that + + + align:start position:0% +what's go back to this and then that +original insert your synthetic gene into + + align:start position:0% +original insert your synthetic gene into + + + align:start position:0% +original insert your synthetic gene into +it loose that ya rectangle like he + + align:start position:0% +it loose that ya rectangle like he + + + align:start position:0% +it loose that ya rectangle like he +basically came up with that wasn't exist + + align:start position:0% +basically came up with that wasn't exist + + + align:start position:0% +basically came up with that wasn't exist +before and now it's used every day and + + align:start position:0% +before and now it's used every day and + + + align:start position:0% +before and now it's used every day and +almost everything like of the biology + + align:start position:0% +almost everything like of the biology + + + align:start position:0% +almost everything like of the biology +lab yeah so I don't think that the + + align:start position:0% +lab yeah so I don't think that the + + + align:start position:0% +lab yeah so I don't think that the +pharmaceuticals wrong to this okay yeah + + align:start position:0% +pharmaceuticals wrong to this okay yeah + + + align:start position:0% +pharmaceuticals wrong to this okay yeah +looking at that you can try and guess + + align:start position:0% +looking at that you can try and guess + + + align:start position:0% +looking at that you can try and guess +which one went to the Sloan School Boyer + + align:start position:0% +which one went to the Sloan School Boyer + + + align:start position:0% +which one went to the Sloan School Boyer +almost never looked that good let me do + + align:start position:0% + + + + align:start position:0% + +and masters right how about another good + + align:start position:0% +and masters right how about another good + + + align:start position:0% +and masters right how about another good +question cement so something that of + + align:start position:0% +question cement so something that of + + + align:start position:0% +question cement so something that of +some of you who had read this kind of + + align:start position:0% +some of you who had read this kind of + + + align:start position:0% +some of you who had read this kind of +raised and I was curious about as well + + align:start position:0% +raised and I was curious about as well + + + align:start position:0% +raised and I was curious about as well +it was so the initial years because it + + align:start position:0% +it was so the initial years because it + + + align:start position:0% +it was so the initial years because it +was so new and because they were doing + + align:start position:0% +was so new and because they were doing + + + align:start position:0% +was so new and because they were doing +something that hadn't been done before + + align:start position:0% +something that hadn't been done before + + + align:start position:0% +something that hadn't been done before +there was an increased amount of + + align:start position:0% +there was an increased amount of + + + align:start position:0% +there was an increased amount of +risk-taking that was needed and you know + + align:start position:0% +risk-taking that was needed and you know + + + align:start position:0% +risk-taking that was needed and you know +they both really staked their careers on + + align:start position:0% +they both really staked their careers on + + + align:start position:0% +they both really staked their careers on +it especially Swanson who ended up + + align:start position:0% +it especially Swanson who ended up + + + align:start position:0% +it especially Swanson who ended up +having to check himself at the hospital + + align:start position:0% +having to check himself at the hospital + + + align:start position:0% +having to check himself at the hospital +when they had sat back so I wonder if + + align:start position:0% +when they had sat back so I wonder if + + + align:start position:0% +when they had sat back so I wonder if +there's kind of a way to encourage more + + align:start position:0% +there's kind of a way to encourage more + + + align:start position:0% +there's kind of a way to encourage more +sustainable risk-taking in people who + + align:start position:0% +sustainable risk-taking in people who + + + align:start position:0% +sustainable risk-taking in people who +have the visions like Swanson and people + + align:start position:0% +have the visions like Swanson and people + + + align:start position:0% +have the visions like Swanson and people +who you know people who are we were + + align:start position:0% +who you know people who are we were + + + align:start position:0% +who you know people who are we were +starting up endeavors like this there + + align:start position:0% +starting up endeavors like this there + + + align:start position:0% +starting up endeavors like this there +was a way to make that they are + + align:start position:0% +was a way to make that they are + + + align:start position:0% +was a way to make that they are +incentive to artists advice to take + + align:start position:0% +incentive to artists advice to take + + + align:start position:0% +incentive to artists advice to take +these risks that are necessary to + + align:start position:0% +these risks that are necessary to + + + align:start position:0% +these risks that are necessary to +further their careers but also maybe not + + align:start position:0% +further their careers but also maybe not + + + align:start position:0% +further their careers but also maybe not +to the point that's what's a good when + + align:start position:0% +to the point that's what's a good when + + + align:start position:0% +to the point that's what's a good when +I've led three innovation groups where I + + align:start position:0% +I've led three innovation groups where I + + + align:start position:0% +I've led three innovation groups where I +teach certain people not just students + + align:start position:0% +teach certain people not just students + + + align:start position:0% +teach certain people not just students +for people the engineering design cycle + + align:start position:0% +for people the engineering design cycle + + + align:start position:0% +for people the engineering design cycle +and I think one of my big takeaway is + + align:start position:0% +and I think one of my big takeaway is + + + align:start position:0% +and I think one of my big takeaway is +you know having taught students as young + + align:start position:0% +you know having taught students as young + + + align:start position:0% +you know having taught students as young +as five years old to you know + + align:start position:0% +as five years old to you know + + + align:start position:0% +as five years old to you know +individuals is all missing and their + + align:start position:0% +individuals is all missing and their + + + align:start position:0% +individuals is all missing and their +50th eighteen sixties is that there + + align:start position:0% +50th eighteen sixties is that there + + + align:start position:0% +50th eighteen sixties is that there +really needs to be a sense of safety and + + align:start position:0% +really needs to be a sense of safety and + + + align:start position:0% +really needs to be a sense of safety and +security which is something that was + + align:start position:0% +security which is something that was + + + align:start position:0% +security which is something that was +brought up I think is a Biederman + + align:start position:0% +brought up I think is a Biederman + + + align:start position:0% +brought up I think is a Biederman +reading which is I think one of the + + align:start position:0% +reading which is I think one of the + + + align:start position:0% +reading which is I think one of the +reasons why there's that sort of a big + + align:start position:0% +reasons why there's that sort of a big + + + align:start position:0% +reasons why there's that sort of a big +paradigm of founding a company out of + + align:start position:0% +paradigm of founding a company out of + + + align:start position:0% +paradigm of founding a company out of +your dorm room because there's something + + align:start position:0% +your dorm room because there's something + + + align:start position:0% +your dorm room because there's something +that's implied there which is that you + + align:start position:0% +that's implied there which is that you + + + align:start position:0% +that's implied there which is that you +have a place to live and then if you you + + align:start position:0% +have a place to live and then if you you + + + align:start position:0% +have a place to live and then if you you +know attend an institution where you + + align:start position:0% +know attend an institution where you + + + align:start position:0% +know attend an institution where you +have a dorm you also have access to food + + align:start position:0% +have a dorm you also have access to food + + + align:start position:0% +have a dorm you also have access to food +and you're also not super concerned + + align:start position:0% +and you're also not super concerned + + + align:start position:0% +and you're also not super concerned +about getting a paycheck and so I think + + align:start position:0% +about getting a paycheck and so I think + + + align:start position:0% +about getting a paycheck and so I think +that sense of security sort of both + + align:start position:0% +that sense of security sort of both + + + align:start position:0% +that sense of security sort of both +mentally to sort of take a step back and + + align:start position:0% +mentally to sort of take a step back and + + + align:start position:0% +mentally to sort of take a step back and +explore your dreams is really important + + align:start position:0% +explore your dreams is really important + + + align:start position:0% +explore your dreams is really important +in to the sense of stability + + align:start position:0% +in to the sense of stability + + + align:start position:0% +in to the sense of stability +like literally access to shelter access + + align:start position:0% +like literally access to shelter access + + + align:start position:0% +like literally access to shelter access +to food access to health care becomes + + align:start position:0% +to food access to health care becomes + + + align:start position:0% +to food access to health care becomes +really important so in those + + align:start position:0% +really important so in those + + + align:start position:0% +really important so in those +circumstances I feel like universities + + align:start position:0% +circumstances I feel like universities + + + align:start position:0% +circumstances I feel like universities +not just maybe their undergraduate + + align:start position:0% +not just maybe their undergraduate + + + align:start position:0% +not just maybe their undergraduate +programs but maybe universities + + align:start position:0% +programs but maybe universities + + + align:start position:0% +programs but maybe universities +generally provide really interesting + + align:start position:0% +generally provide really interesting + + + align:start position:0% +generally provide really interesting +opportunities to innovate for these + + align:start position:0% +opportunities to innovate for these + + + align:start position:0% +opportunities to innovate for these +kinds of you know very disruptive + + align:start position:0% +kinds of you know very disruptive + + + align:start position:0% +kinds of you know very disruptive +innovations because they do provide that + + align:start position:0% +innovations because they do provide that + + + align:start position:0% +innovations because they do provide that +sort of holistic support to an + + align:start position:0% +sort of holistic support to an + + + align:start position:0% +sort of holistic support to an +individual but that's still a theory + + align:start position:0% +individual but that's still a theory + + + align:start position:0% +individual but that's still a theory +that I'm working under and you know sort + + align:start position:0% +that I'm working under and you know sort + + + align:start position:0% +that I'm working under and you know sort +of hope to continue exploring over maybe + + align:start position:0% +of hope to continue exploring over maybe + + + align:start position:0% +of hope to continue exploring over maybe +master's thesis or a PhD but I think the + + align:start position:0% +master's thesis or a PhD but I think the + + + align:start position:0% +master's thesis or a PhD but I think the +other really big point about mental + + align:start position:0% +other really big point about mental + + + align:start position:0% +other really big point about mental +health is something that was also + + align:start position:0% +health is something that was also + + + align:start position:0% +health is something that was also +addressed in the Biederman reading and + + align:start position:0% +addressed in the Biederman reading and + + + align:start position:0% +addressed in the Biederman reading and +he goes back to that sense of safety and + + align:start position:0% +he goes back to that sense of safety and + + + align:start position:0% +he goes back to that sense of safety and +security that a lot of times individuals + + align:start position:0% +security that a lot of times individuals + + + align:start position:0% +security that a lot of times individuals +who don't feel comfortable in their sort + + align:start position:0% +who don't feel comfortable in their sort + + + align:start position:0% +who don't feel comfortable in their sort +of organic or natural ecosystem feel + + align:start position:0% +of organic or natural ecosystem feel + + + align:start position:0% +of organic or natural ecosystem feel +more stressed and thus that prevents + + align:start position:0% +more stressed and thus that prevents + + + align:start position:0% +more stressed and thus that prevents +them from being productive and so I + + align:start position:0% +them from being productive and so I + + + align:start position:0% +them from being productive and so I +think about that in the context of the + + align:start position:0% +think about that in the context of the + + + align:start position:0% +think about that in the context of the +current political situation and the ways + + align:start position:0% +current political situation and the ways + + + align:start position:0% +current political situation and the ways +in which maybe some people who might be + + align:start position:0% +in which maybe some people who might be + + + align:start position:0% +in which maybe some people who might be +interested in innovating or pursuing + + align:start position:0% +interested in innovating or pursuing + + + align:start position:0% +interested in innovating or pursuing +innovative projects may not be able to + + align:start position:0% +innovative projects may not be able to + + + align:start position:0% +innovative projects may not be able to +do so effectively because of the ways in + + align:start position:0% +do so effectively because of the ways in + + + align:start position:0% +do so effectively because of the ways in +which the political situation is you + + align:start position:0% +which the political situation is you + + + align:start position:0% +which the political situation is you +know literally motivating stress in + + align:start position:0% +know literally motivating stress in + + + align:start position:0% +know literally motivating stress in +their lives and is preventing them from + + align:start position:0% +their lives and is preventing them from + + + align:start position:0% +their lives and is preventing them from +innovating so those are some thoughts I + + align:start position:0% +innovating so those are some thoughts I + + + align:start position:0% +innovating so those are some thoughts I +have a lot of them you should share + + align:start position:0% +have a lot of them you should share + + + align:start position:0% +have a lot of them you should share +those to this aspect of having stress + + align:start position:0% +those to this aspect of having stress + + + align:start position:0% +those to this aspect of having stress +like a necessary stress is important + + align:start position:0% +like a necessary stress is important + + + align:start position:0% +like a necessary stress is important +like I think with the Manhattan Project + + align:start position:0% +like I think with the Manhattan Project + + + align:start position:0% +like I think with the Manhattan Project +like there's no safety and security and + + align:start position:0% +like there's no safety and security and + + + align:start position:0% +like there's no safety and security and +measurements are gonna give the + + align:start position:0% +measurements are gonna give the + + + align:start position:0% +measurements are gonna give the +conference and I mean I couldn't think + + align:start position:0% +conference and I mean I couldn't think + + + align:start position:0% +conference and I mean I couldn't think +of a better impetus that you know this + + align:start position:0% +of a better impetus that you know this + + + align:start position:0% +of a better impetus that you know this +has to work for I don't have a house to + + align:start position:0% +has to work for I don't have a house to + + + align:start position:0% +has to work for I don't have a house to +live in or if we D + + align:start position:0% + + + + align:start position:0% + +that's actually not what they had to + + align:start position:0% +that's actually not what they had to + + + align:start position:0% +that's actually not what they had to +deal with it all I mean like they might + + align:start position:0% +deal with it all I mean like they might + + + align:start position:0% +deal with it all I mean like they might +say like yeah oh we don't have any flies + + align:start position:0% +say like yeah oh we don't have any flies + + + align:start position:0% +say like yeah oh we don't have any flies +but so I kind of agree but I mean + + align:start position:0% +but so I kind of agree but I mean + + + align:start position:0% +but so I kind of agree but I mean +Oppenheimer didn't mention in that paper + + align:start position:0% +Oppenheimer didn't mention in that paper + + + align:start position:0% +Oppenheimer didn't mention in that paper +like he went six months and he didn't + + align:start position:0% +like he went six months and he didn't + + + align:start position:0% +like he went six months and he didn't +even realize he had a pro paycheck yet + + align:start position:0% +even realize he had a pro paycheck yet + + + align:start position:0% +even realize he had a pro paycheck yet +he hadn't received one and I saw that + + align:start position:0% +he hadn't received one and I saw that + + + align:start position:0% +he hadn't received one and I saw that +and I just thought that was such + + align:start position:0% +and I just thought that was such + + + align:start position:0% +and I just thought that was such +privilege so the fact that someone could + + align:start position:0% +privilege so the fact that someone could + + + align:start position:0% +privilege so the fact that someone could +have that that sense of okay well if + + align:start position:0% +have that that sense of okay well if + + + align:start position:0% +have that that sense of okay well if +this ignoring the implications of + + align:start position:0% +this ignoring the implications of + + + align:start position:0% +this ignoring the implications of +obviously failing on this project + + align:start position:0% +obviously failing on this project + + + align:start position:0% +obviously failing on this project +outside of the Manhattan Project any + + align:start position:0% +outside of the Manhattan Project any + + + align:start position:0% +outside of the Manhattan Project any +other technological pursuit I think that + + align:start position:0% +other technological pursuit I think that + + + align:start position:0% +other technological pursuit I think that +definitely helps with Korea think more + + align:start position:0% +definitely helps with Korea think more + + + align:start position:0% +definitely helps with Korea think more +creatively when you have to think about + + align:start position:0% +creatively when you have to think about + + + align:start position:0% +creatively when you have to think about +oh how am I gonna pay for my car or how + + align:start position:0% +oh how am I gonna pay for my car or how + + + align:start position:0% +oh how am I gonna pay for my car or how +am I gonna get to work or whatever so + + align:start position:0% +am I gonna get to work or whatever so + + + align:start position:0% +am I gonna get to work or whatever so +one of the important rules I think here + + align:start position:0% +one of the important rules I think here + + + align:start position:0% +one of the important rules I think here +is that the group needs to be on a + + align:start position:0% +is that the group needs to be on a + + + align:start position:0% +is that the group needs to be on a +protected island and the point you're + + align:start position:0% +protected island and the point you're + + + align:start position:0% +protected island and the point you're +adding stuff I think is a significant + + align:start position:0% +adding stuff I think is a significant + + + align:start position:0% +adding stuff I think is a significant +one it needs to feel secure in itself + + align:start position:0% +one it needs to feel secure in itself + + + align:start position:0% +one it needs to feel secure in itself +right people have to be comfortable in + + align:start position:0% +right people have to be comfortable in + + + align:start position:0% +right people have to be comfortable in +this group to be willing to be creative + + align:start position:0% +this group to be willing to be creative + + + align:start position:0% +this group to be willing to be creative +together and contribute to each other I + + align:start position:0% +together and contribute to each other I + + + align:start position:0% +together and contribute to each other I +think that's an important perception + + align:start position:0% +think that's an important perception + + + align:start position:0% +think that's an important perception +here that probably applies to a lot of + + align:start position:0% +here that probably applies to a lot of + + + align:start position:0% +here that probably applies to a lot of +these groups but why having too little + + align:start position:0% +these groups but why having too little + + + align:start position:0% +these groups but why having too little +means so much you don't have your full + + align:start position:0% +means so much you don't have your full + + + align:start position:0% +means so much you don't have your full +band widths if you're worried about what + + align:start position:0% +band widths if you're worried about what + + + align:start position:0% +band widths if you're worried about what +you don't have and what you need to work + + align:start position:0% +you don't have and what you need to work + + + align:start position:0% +you don't have and what you need to work +on so and that's front up for you to do + + align:start position:0% +on so and that's front up for you to do + + + align:start position:0% +on so and that's front up for you to do +so then did this group have that sense + + align:start position:0% +so then did this group have that sense + + + align:start position:0% +so then did this group have that sense +of security from what I read here they + + align:start position:0% +of security from what I read here they + + + align:start position:0% +of security from what I read here they +definitely did I mean a lot of them were + + align:start position:0% +definitely did I mean a lot of them were + + + align:start position:0% +definitely did I mean a lot of them were +and you don't see in this picture the + + align:start position:0% +and you don't see in this picture the + + + align:start position:0% +and you don't see in this picture the +whole team it is a whole team that's + + align:start position:0% +whole team it is a whole team that's + + + align:start position:0% +whole team it is a whole team that's +very collaborative with these with this + + align:start position:0% +very collaborative with these with this + + + align:start position:0% +very collaborative with these with this +duo yeah and I think that that was an + + align:start position:0% +duo yeah and I think that that was an + + + align:start position:0% +duo yeah and I think that that was an +interesting point about I did kind of + + align:start position:0% +interesting point about I did kind of + + + align:start position:0% +interesting point about I did kind of +get a sense that like class 10 came into + + align:start position:0% +get a sense that like class 10 came into + + + align:start position:0% +get a sense that like class 10 came into +this in a way that you know really + + align:start position:0% +this in a way that you know really + + + align:start position:0% +this in a way that you know really +benefited you know Boyer had this he + + align:start position:0% +benefited you know Boyer had this he + + + align:start position:0% +benefited you know Boyer had this he +went into a commercial I think because + + align:start position:0% +went into a commercial I think because + + + align:start position:0% +went into a commercial I think because +he had an altruistic vision or just + + align:start position:0% +he had an altruistic vision or just + + + align:start position:0% +he had an altruistic vision or just +interesting but he also you know he had + + align:start position:0% +interesting but he also you know he had + + + align:start position:0% +interesting but he also you know he had +that ability to not have to worry about + + align:start position:0% +that ability to not have to worry about + + + align:start position:0% +that ability to not have to worry about +making money and things like that so I + + align:start position:0% +making money and things like that so I + + + align:start position:0% +making money and things like that so I +think that's a really interesting point + + align:start position:0% +think that's a really interesting point + + + align:start position:0% +think that's a really interesting point +that you all raised and yeah we were + + align:start position:0% +that you all raised and yeah we were + + + align:start position:0% +that you all raised and yeah we were +saying about how people who feel like + + align:start position:0% +saying about how people who feel like + + + align:start position:0% +saying about how people who feel like +they are actively under threat or to + + align:start position:0% +they are actively under threat or to + + + align:start position:0% +they are actively under threat or to +actively don't have you know the basic + + align:start position:0% +actively don't have you know the basic + + + align:start position:0% +actively don't have you know the basic +necessity necessity is taken care of + + align:start position:0% +necessity necessity is taken care of + + + align:start position:0% +necessity necessity is taken care of +would not be able to function maybe the + + align:start position:0% +would not be able to function maybe the + + + align:start position:0% +would not be able to function maybe the +way that you make those innovations in + + align:start position:0% +way that you make those innovations in + + + align:start position:0% +way that you make those innovations in +right during an island then I was + + align:start position:0% +right during an island then I was + + + align:start position:0% +right during an island then I was +starving book by Paul Corning you did he + + align:start position:0% +starving book by Paul Corning you did he + + + align:start position:0% +starving book by Paul Corning you did he +was a neuroscientist who was a resident + + align:start position:0% +was a neuroscientist who was a resident + + + align:start position:0% +was a neuroscientist who was a resident +I believe at Stanford you're a surgeon + + align:start position:0% +I believe at Stanford you're a surgeon + + + align:start position:0% +I believe at Stanford you're a surgeon +oh he was a medical resident at Stanford + + align:start position:0% +oh he was a medical resident at Stanford + + + align:start position:0% +oh he was a medical resident at Stanford +who's just about to complete his new + + align:start position:0% +who's just about to complete his new + + + align:start position:0% +who's just about to complete his new +science residency and he was diagnosed + + align:start position:0% +science residency and he was diagnosed + + + align:start position:0% +science residency and he was diagnosed +with brain cancer and he ended up + + align:start position:0% +with brain cancer and he ended up + + + align:start position:0% +with brain cancer and he ended up +passing away just shy of you know + + align:start position:0% +passing away just shy of you know + + + align:start position:0% +passing away just shy of you know +completing his residency but there is a + + align:start position:0% +completing his residency but there is a + + + align:start position:0% +completing his residency but there is a +really incredible portion in his memoir + + align:start position:0% +really incredible portion in his memoir + + + align:start position:0% +really incredible portion in his memoir +where he talks about what he had to do + + align:start position:0% +where he talks about what he had to do + + + align:start position:0% +where he talks about what he had to do +in order to be able to achieve what he + + align:start position:0% +in order to be able to achieve what he + + + align:start position:0% +in order to be able to achieve what he +did which is essentially after going to + + align:start position:0% +did which is essentially after going to + + + align:start position:0% +did which is essentially after going to +Stanford undergrad he spent a year + + align:start position:0% +Stanford undergrad he spent a year + + + align:start position:0% +Stanford undergrad he spent a year +essentially being homeless living in an + + align:start position:0% +essentially being homeless living in an + + + align:start position:0% +essentially being homeless living in an +abandoned home and taking classes at + + align:start position:0% +abandoned home and taking classes at + + + align:start position:0% +abandoned home and taking classes at +Stanford while studying for the MCAT and + + align:start position:0% +Stanford while studying for the MCAT and + + + align:start position:0% +Stanford while studying for the MCAT and +I think there's a really other reason I + + align:start position:0% +I think there's a really other reason I + + + align:start position:0% +I think there's a really other reason I +recommend everyone read this book if + + align:start position:0% +recommend everyone read this book if + + + align:start position:0% +recommend everyone read this book if +they're interested in becoming + + align:start position:0% +they're interested in becoming + + + align:start position:0% +they're interested in becoming +innovators or entrepreneurs or you know + + align:start position:0% +innovators or entrepreneurs or you know + + + align:start position:0% +innovators or entrepreneurs or you know +people who change the world is that he + + align:start position:0% +people who change the world is that he + + + align:start position:0% +people who change the world is that he +elicits a really great point about not + + align:start position:0% +elicits a really great point about not + + + align:start position:0% +elicits a really great point about not +necessarily just couldn't go up the male + + align:start position:0% +necessarily just couldn't go up the male + + + align:start position:0% +necessarily just couldn't go up the male +privilege but just privilege generally + + align:start position:0% +privilege but just privilege generally + + + align:start position:0% +privilege but just privilege generally +because he was able to sort of an opt + + align:start position:0% +because he was able to sort of an opt + + + align:start position:0% +because he was able to sort of an opt +out of being alive and utilize whatever + + align:start position:0% +out of being alive and utilize whatever + + + align:start position:0% +out of being alive and utilize whatever +money his parents were sending him or + + align:start position:0% +money his parents were sending him or + + + align:start position:0% +money his parents were sending him or +whatever money he had saved job in order + + align:start position:0% +whatever money he had saved job in order + + + align:start position:0% +whatever money he had saved job in order +to take these classes in order to study + + align:start position:0% +to take these classes in order to study + + + align:start position:0% +to take these classes in order to study +for the MCAT and and go on you know to + + align:start position:0% +for the MCAT and and go on you know to + + + align:start position:0% +for the MCAT and and go on you know to +do incredible work in medical school + + align:start position:0% +do incredible work in medical school + + + align:start position:0% +do incredible work in medical school +women in residency and I feel like + + align:start position:0% +women in residency and I feel like + + + align:start position:0% +women in residency and I feel like +that's a sort of close as you get and + + align:start position:0% +that's a sort of close as you get and + + + align:start position:0% +that's a sort of close as you get and +the clearest sort of articulation of the + + align:start position:0% +the clearest sort of articulation of the + + + align:start position:0% +the clearest sort of articulation of the +process of giving up your whole life in + + align:start position:0% +process of giving up your whole life in + + + align:start position:0% +process of giving up your whole life in +order to pursue this big dream that you + + align:start position:0% +order to pursue this big dream that you + + + align:start position:0% +order to pursue this big dream that you +have + + align:start position:0% +have + + + align:start position:0% +have +and so Paul clinic's book I think is a + + align:start position:0% +and so Paul clinic's book I think is a + + + align:start position:0% +and so Paul clinic's book I think is a +really really great study not just of a + + align:start position:0% +really really great study not just of a + + + align:start position:0% +really really great study not just of a +great group of a great individual and a + + align:start position:0% +great group of a great individual and a + + + align:start position:0% +great group of a great individual and a +person who's sort of a risk-taker and + + align:start position:0% +person who's sort of a risk-taker and + + + align:start position:0% +person who's sort of a risk-taker and +willing to give up their life for their + + align:start position:0% +willing to give up their life for their + + + align:start position:0% +willing to give up their life for their +work and then ultimately obviously you + + align:start position:0% +work and then ultimately obviously you + + + align:start position:0% +work and then ultimately obviously you +know the conclusion of it is you know + + align:start position:0% +know the conclusion of it is you know + + + align:start position:0% +know the conclusion of it is you know +quite rude + + align:start position:0% +quite rude + + + align:start position:0% +quite rude +near any markets there but these folks + + align:start position:0% +near any markets there but these folks + + + align:start position:0% +near any markets there but these folks +are giving up you know a tremendous + + align:start position:0% +are giving up you know a tremendous + + + align:start position:0% +are giving up you know a tremendous +amount to pursue a dream only linking of + + align:start position:0% +amount to pursue a dream only linking of + + + align:start position:0% +amount to pursue a dream only linking of +the winners right I would say that + + align:start position:0% +the winners right I would say that + + + align:start position:0% +the winners right I would say that +pretty much every biotech entrepreneur + + align:start position:0% +pretty much every biotech entrepreneur + + + align:start position:0% +pretty much every biotech entrepreneur +ends up with all servers of high blood + + align:start position:0% +ends up with all servers of high blood + + + align:start position:0% +ends up with all servers of high blood +pressure that's just they do she only + + align:start position:0% +pressure that's just they do she only + + + align:start position:0% +pressure that's just they do she only +said biotech with the biotech side but I + + align:start position:0% +said biotech with the biotech side but I + + + align:start position:0% +said biotech with the biotech side but I +think that because these I think that's + + align:start position:0% +think that because these I think that's + + + align:start position:0% +think that because these I think that's +also a characteristic of the great group + + align:start position:0% +also a characteristic of the great group + + + align:start position:0% +also a characteristic of the great group +leaders that they're able to take risks + + align:start position:0% +leaders that they're able to take risks + + + align:start position:0% +leaders that they're able to take risks +and get ulcers so that the rest of their + + align:start position:0% +and get ulcers so that the rest of their + + + align:start position:0% +and get ulcers so that the rest of their +team can feel the insulation and as + + align:start position:0% +team can feel the insulation and as + + + align:start position:0% +team can feel the insulation and as +though they have the opportunity for + + align:start position:0% +though they have the opportunity for + + + align:start position:0% +though they have the opportunity for +success resources and security so I + + align:start position:0% +success resources and security so I + + + align:start position:0% +success resources and security so I +think that's an aspect of this yeah + + align:start position:0% +think that's an aspect of this yeah + + + align:start position:0% +think that's an aspect of this yeah +there are some others of quote in the + + align:start position:0% +there are some others of quote in the + + + align:start position:0% +there are some others of quote in the +paper that was the scientist at + + align:start position:0% +paper that was the scientist at + + + align:start position:0% +paper that was the scientist at +Genentech had a new boss other than this + + align:start position:0% +Genentech had a new boss other than this + + + align:start position:0% +Genentech had a new boss other than this +one thens nervous vigilance so that + + align:start position:0% +one thens nervous vigilance so that + + + align:start position:0% +one thens nervous vigilance so that +really like that's a great line so yeah + + align:start position:0% +really like that's a great line so yeah + + + align:start position:0% +really like that's a great line so yeah +it's good + + align:start position:0% +it's good + + + align:start position:0% +it's good +all right let's do Venter Lily so I'm + + align:start position:0% +all right let's do Venter Lily so I'm + + + align:start position:0% +all right let's do Venter Lily so I'm +going over the craig venter great group + + align:start position:0% +going over the craig venter great group + + + align:start position:0% +going over the craig venter great group +today a few of you have heard of him + + align:start position:0% +today a few of you have heard of him + + + align:start position:0% +today a few of you have heard of him +most have not the leader of the great + + align:start position:0% +most have not the leader of the great + + + align:start position:0% +most have not the leader of the great +group of course was craig Venter and + + align:start position:0% +group of course was craig Venter and + + + align:start position:0% +group of course was craig Venter and +just going through some of the venison + + align:start position:0% +just going through some of the venison + + + align:start position:0% +just going through some of the venison +Biederman necessities of great Brutus or + + align:start position:0% +Biederman necessities of great Brutus or + + + align:start position:0% +Biederman necessities of great Brutus or +greatness in a group his mission from + + align:start position:0% +greatness in a group his mission from + + + align:start position:0% +greatness in a group his mission from +God was to sequence and decode the human + + align:start position:0% +God was to sequence and decode the human + + + align:start position:0% +God was to sequence and decode the human +genome so check we have a mission from + + align:start position:0% +genome so check we have a mission from + + + align:start position:0% +genome so check we have a mission from +God the island in this particular case + + align:start position:0% +God the island in this particular case + + + align:start position:0% +God the island in this particular case +study while they were decoding + + align:start position:0% +study while they were decoding + + + align:start position:0% +study while they were decoding +sequencing and decoding human genome + + align:start position:0% +sequencing and decoding human genome + + + align:start position:0% +sequencing and decoding human genome +their island was Solera which was a + + align:start position:0% +their island was Solera which was a + + + align:start position:0% +their island was Solera which was a +biotech that was it's complicated I'm + + align:start position:0% +biotech that was it's complicated I'm + + + align:start position:0% +biotech that was it's complicated I'm +gonna try to keep it as simple as + + align:start position:0% +gonna try to keep it as simple as + + + align:start position:0% +gonna try to keep it as simple as +possible for the purposes of this + + align:start position:0% +possible for the purposes of this + + + align:start position:0% +possible for the purposes of this +presentation + + align:start position:0% +presentation + + + align:start position:0% +presentation +just know that craig Venter had like + + align:start position:0% +just know that craig Venter had like + + + align:start position:0% +just know that craig Venter had like +many many for profits and non for + + align:start position:0% +many many for profits and non for + + + align:start position:0% +many many for profits and non for +profits institutions all running at the + + align:start position:0% +profits institutions all running at the + + + align:start position:0% +profits institutions all running at the +same time he has net he has + + align:start position:0% +same time he has net he has + + + align:start position:0% +same time he has net he has +now more than used to so I'm just really + + align:start position:0% +now more than used to so I'm just really + + + align:start position:0% +now more than used to so I'm just really +gonna talk about Solera for the purposes + + align:start position:0% +gonna talk about Solera for the purposes + + + align:start position:0% +gonna talk about Solera for the purposes +of this presentation and then the + + align:start position:0% +of this presentation and then the + + + align:start position:0% +of this presentation and then the +mainland he has connections with the + + align:start position:0% +mainland he has connections with the + + + align:start position:0% +mainland he has connections with the +public there's a lot of publicity going + + align:start position:0% +public there's a lot of publicity going + + + align:start position:0% +public there's a lot of publicity going +on for at this time over the Human + + align:start position:0% +on for at this time over the Human + + + align:start position:0% +on for at this time over the Human +Genome Project so that's sort of their + + align:start position:0% +Genome Project so that's sort of their + + + align:start position:0% +Genome Project so that's sort of their +their highway to the the public or the + + align:start position:0% +their highway to the the public or the + + + align:start position:0% +their highway to the the public or the +mainland + + align:start position:0% +mainland + + + align:start position:0% +mainland +annie has contacts still at the NIH and + + align:start position:0% +annie has contacts still at the NIH and + + + align:start position:0% +annie has contacts still at the NIH and +adversaries at the NIH as well and they + + align:start position:0% +adversaries at the NIH as well and they + + + align:start position:0% +adversaries at the NIH as well and they +are indeed the underdog Craig Venters + + align:start position:0% +are indeed the underdog Craig Venters + + + align:start position:0% +are indeed the underdog Craig Venters +great group defect from the NIH and + + align:start position:0% +great group defect from the NIH and + + + align:start position:0% +great group defect from the NIH and +they're up against funding from the US + + align:start position:0% +they're up against funding from the US + + + align:start position:0% +they're up against funding from the US +government and actually international + + align:start position:0% +government and actually international + + + align:start position:0% +government and actually international +collaboration especially with the + + align:start position:0% +collaboration especially with the + + + align:start position:0% +collaboration especially with the +British government and the anyway I + + align:start position:0% +British government and the anyway I + + + align:start position:0% +British government and the anyway I +think it's actually wants and rather + + align:start position:0% +think it's actually wants and rather + + + align:start position:0% +think it's actually wants and rather +than Crick right oh yeah yeah yeah sorry + + align:start position:0% + + + + align:start position:0% + +no Branson's Kirk had nothing to do with + + align:start position:0% +no Branson's Kirk had nothing to do with + + + align:start position:0% +no Branson's Kirk had nothing to do with +this it was a lot and Watson was heading + + align:start position:0% +this it was a lot and Watson was heading + + + align:start position:0% +this it was a lot and Watson was heading +the genome project at NIH at the time + + align:start position:0% +the genome project at NIH at the time + + + align:start position:0% +the genome project at NIH at the time +yeah yeah drives men to rev it so an + + align:start position:0% +yeah yeah drives men to rev it so an + + + align:start position:0% +yeah yeah drives men to rev it so an +inventor and and Watson begin as a very + + align:start position:0% +inventor and and Watson begin as a very + + + align:start position:0% +inventor and and Watson begin as a very +powerful duo and ventur'd thinks that + + align:start position:0% +powerful duo and ventur'd thinks that + + + align:start position:0% +powerful duo and ventur'd thinks that +the genome needs to be sequenced in a + + align:start position:0% +the genome needs to be sequenced in a + + + align:start position:0% +the genome needs to be sequenced in a +slightly different way and Watson is not + + align:start position:0% +slightly different way and Watson is not + + + align:start position:0% +slightly different way and Watson is not +okay with that because so much money and + + align:start position:0% +okay with that because so much money and + + + align:start position:0% +okay with that because so much money and +so much effort has been put into it the + + align:start position:0% +so much effort has been put into it the + + + align:start position:0% +so much effort has been put into it the +sort of outdated way and he completely + + align:start position:0% +sort of outdated way and he completely + + + align:start position:0% +sort of outdated way and he completely +undermines mentor in front of US + + align:start position:0% +undermines mentor in front of US + + + align:start position:0% +undermines mentor in front of US +Congress etcetera I'll get into that a + + align:start position:0% +Congress etcetera I'll get into that a + + + align:start position:0% +Congress etcetera I'll get into that a +little more but yeah basically the enemy + + align:start position:0% +little more but yeah basically the enemy + + + align:start position:0% +little more but yeah basically the enemy +is anyone who pisses off Venter which + + align:start position:0% +is anyone who pisses off Venter which + + + align:start position:0% +is anyone who pisses off Venter which +turns out to be quite a lot of people + + align:start position:0% +turns out to be quite a lot of people + + + align:start position:0% +turns out to be quite a lot of people +over here she's Venter Craig mentor I + + align:start position:0% +over here she's Venter Craig mentor I + + + align:start position:0% +over here she's Venter Craig mentor I +think is one of them more one of the + + align:start position:0% +think is one of them more one of the + + + align:start position:0% +think is one of them more one of the +most controversial scientists in biotech + + align:start position:0% +most controversial scientists in biotech + + + align:start position:0% +most controversial scientists in biotech +in our time + + align:start position:0% +in our time + + + align:start position:0% +in our time +he's a very little bit of a hothead + + align:start position:0% +he's a very little bit of a hothead + + + align:start position:0% +he's a very little bit of a hothead +and he people in science either love him + + align:start position:0% +and he people in science either love him + + + align:start position:0% +and he people in science either love him +or hate him so a little bit of + + align:start position:0% +or hate him so a little bit of + + + align:start position:0% +or hate him so a little bit of +background his early life he's sort of + + align:start position:0% +background his early life he's sort of + + + align:start position:0% +background his early life he's sort of +he was reminiscent for me of Thomas + + align:start position:0% +he was reminiscent for me of Thomas + + + align:start position:0% +he was reminiscent for me of Thomas +Edison he has some severe learning + + align:start position:0% +Edison he has some severe learning + + + align:start position:0% +Edison he has some severe learning +issues almost flunked out of high school + + align:start position:0% +issues almost flunked out of high school + + + align:start position:0% +issues almost flunked out of high school +does not go to college he ends up a + + align:start position:0% +does not go to college he ends up a + + + align:start position:0% +does not go to college he ends up a +surfer bum in Southern California on + + align:start position:0% +surfer bum in Southern California on + + + align:start position:0% +surfer bum in Southern California on +Redondo Beach I want to add one fact not + + align:start position:0% +Redondo Beach I want to add one fact not + + + align:start position:0% +Redondo Beach I want to add one fact not +just one parent but both his parents + + align:start position:0% +just one parent but both his parents + + + align:start position:0% +just one parent but both his parents +were Marine sergeants yeah you can only + + align:start position:0% +were Marine sergeants yeah you can only + + + align:start position:0% +were Marine sergeants yeah you can only +imagine what that does to you from this + + align:start position:0% +imagine what that does to you from this + + + align:start position:0% +imagine what that does to you from this +militant household and besides that as + + align:start position:0% +militant household and besides that as + + + align:start position:0% +militant household and besides that as +soon as he's I think used like 17 when + + align:start position:0% +soon as he's I think used like 17 when + + + align:start position:0% +soon as he's I think used like 17 when +he graduates from high school he decides + + align:start position:0% +he graduates from high school he decides + + + align:start position:0% +he graduates from high school he decides +I'm getting out of here I'm gonna live + + align:start position:0% +I'm getting out of here I'm gonna live + + + align:start position:0% +I'm getting out of here I'm gonna live +in Redondo Beach in a surf shack and + + align:start position:0% +in Redondo Beach in a surf shack and + + + align:start position:0% +in Redondo Beach in a surf shack and +grow my hair out long and wear cut-offs + + align:start position:0% +grow my hair out long and wear cut-offs + + + align:start position:0% +grow my hair out long and wear cut-offs +so that was his I think rebellion + + align:start position:0% +so that was his I think rebellion + + + align:start position:0% +so that was his I think rebellion +against his parents this is during the + + align:start position:0% +against his parents this is during the + + + align:start position:0% +against his parents this is during the +time of Vietnam vinter realizes he comes + + align:start position:0% +time of Vietnam vinter realizes he comes + + + align:start position:0% +time of Vietnam vinter realizes he comes +from a military family first of all so I + + align:start position:0% +from a military family first of all so I + + + align:start position:0% +from a military family first of all so I +think he has a somewhat a sense of duty + + align:start position:0% +think he has a somewhat a sense of duty + + + align:start position:0% +think he has a somewhat a sense of duty +but he also realizes that he's probably + + align:start position:0% +but he also realizes that he's probably + + + align:start position:0% +but he also realizes that he's probably +going to get drafted and it's better for + + align:start position:0% +going to get drafted and it's better for + + + align:start position:0% +going to get drafted and it's better for +him if he joins the Navy voluntarily + + align:start position:0% +him if he joins the Navy voluntarily + + + align:start position:0% +him if he joins the Navy voluntarily +he's actually an extremely good + + align:start position:0% +he's actually an extremely good + + + align:start position:0% +he's actually an extremely good +competitive swimmer possibly Olympic + + align:start position:0% +competitive swimmer possibly Olympic + + + align:start position:0% +competitive swimmer possibly Olympic +quality so he joins the Navy thinking + + align:start position:0% +quality so he joins the Navy thinking + + + align:start position:0% +quality so he joins the Navy thinking +that he's going to be on the swim team + + align:start position:0% +that he's going to be on the swim team + + + align:start position:0% +that he's going to be on the swim team +and that actually is the active duty and + + align:start position:0% +and that actually is the active duty and + + + align:start position:0% +and that actually is the active duty and +this turns out to be couldn't be farther + + align:start position:0% +this turns out to be couldn't be farther + + + align:start position:0% +this turns out to be couldn't be farther +from the truth + + align:start position:0% +from the truth + + + align:start position:0% +from the truth +we Vietnam ramps up and he is trained as + + align:start position:0% +we Vietnam ramps up and he is trained as + + + align:start position:0% +we Vietnam ramps up and he is trained as +an EMT and deployed to Da Nang and he + + align:start position:0% +an EMT and deployed to Da Nang and he + + + align:start position:0% +an EMT and deployed to Da Nang and he +actually has two active deployments in + + align:start position:0% +actually has two active deployments in + + + align:start position:0% +actually has two active deployments in +Vietnam these see some things that I + + align:start position:0% +Vietnam these see some things that I + + + align:start position:0% +Vietnam these see some things that I +think changed his life forever in the + + align:start position:0% +think changed his life forever in the + + + align:start position:0% +think changed his life forever in the +interview he talks about how he's the + + align:start position:0% +interview he talks about how he's the + + + align:start position:0% +interview he talks about how he's the +person he is because of his time in + + align:start position:0% +person he is because of his time in + + + align:start position:0% +person he is because of his time in +Vietnam he survives and attends + + align:start position:0% +Vietnam he survives and attends + + + align:start position:0% +Vietnam he survives and attends +Community College in California + + align:start position:0% +Community College in California + + + align:start position:0% +Community College in California +transfers to UCSD which is the + + align:start position:0% +transfers to UCSD which is the + + + align:start position:0% +transfers to UCSD which is the +University of California San Diego gets + + align:start position:0% +University of California San Diego gets + + + align:start position:0% +University of California San Diego gets +a BS and then a PhD there I think he + + align:start position:0% +a BS and then a PhD there I think he + + + align:start position:0% +a BS and then a PhD there I think he +completed his PhD in three years the + + align:start position:0% +completed his PhD in three years the + + + align:start position:0% +completed his PhD in three years the +fastest at that time it was the fastest + + align:start position:0% +fastest at that time it was the fastest + + + align:start position:0% +fastest at that time it was the fastest +biochem PhD in in UCSD history he goes + + align:start position:0% +biochem PhD in in UCSD history he goes + + + align:start position:0% +biochem PhD in in UCSD history he goes +immediately to a faculty position at + + align:start position:0% +immediately to a faculty position at + + + align:start position:0% +immediately to a faculty position at +Buffalo and the + + align:start position:0% +Buffalo and the + + + align:start position:0% +Buffalo and the +or interesting transition for him + + align:start position:0% +or interesting transition for him + + + align:start position:0% +or interesting transition for him +yeah there's that's part of the the + + align:start position:0% +yeah there's that's part of the the + + + align:start position:0% +yeah there's that's part of the the +interview he talks about how he's this + + align:start position:0% +interview he talks about how he's this + + + align:start position:0% +interview he talks about how he's this +Californian with long hair and then goes + + align:start position:0% +Californian with long hair and then goes + + + align:start position:0% +Californian with long hair and then goes +to goes to puffle oh where he begins to + + align:start position:0% +to goes to puffle oh where he begins to + + + align:start position:0% +to goes to puffle oh where he begins to +make people angry actually so he starts + + align:start position:0% +make people angry actually so he starts + + + align:start position:0% +make people angry actually so he starts +young his fat so he marries his PhD + + align:start position:0% +young his fat so he marries his PhD + + + align:start position:0% +young his fat so he marries his PhD +student Claire Fraser he's very clear + + align:start position:0% +student Claire Fraser he's very clear + + + align:start position:0% +student Claire Fraser he's very clear +that they get married after she + + align:start position:0% +that they get married after she + + + align:start position:0% +that they get married after she +graduates so there's nothing wrong with + + align:start position:0% +graduates so there's nothing wrong with + + + align:start position:0% +graduates so there's nothing wrong with +that at all and in 1984 he leaves + + align:start position:0% +that at all and in 1984 he leaves + + + align:start position:0% +that at all and in 1984 he leaves +Buffalo pretty much so that she can + + align:start position:0% +Buffalo pretty much so that she can + + + align:start position:0% +Buffalo pretty much so that she can +start her prove herself as her own + + align:start position:0% +start her prove herself as her own + + + align:start position:0% +start her prove herself as her own +scientist at the end age and I think + + align:start position:0% +scientist at the end age and I think + + + align:start position:0% +scientist at the end age and I think +this is where the the great group really + + align:start position:0% +this is where the the great group really + + + align:start position:0% +this is where the the great group really +starts to coalesce and starts to deform + + align:start position:0% + + + + align:start position:0% + +so the sequence of events at the NIF so + + align:start position:0% +so the sequence of events at the NIF so + + + align:start position:0% +so the sequence of events at the NIF so +while at the NIH Venter is traditionally + + align:start position:0% +while at the NIH Venter is traditionally + + + align:start position:0% +while at the NIH Venter is traditionally +trained as a neuroscientist working in + + align:start position:0% +trained as a neuroscientist working in + + + align:start position:0% +trained as a neuroscientist working in +receptors so is Claire Fraser they have + + align:start position:0% +receptors so is Claire Fraser they have + + + align:start position:0% +receptors so is Claire Fraser they have +separate left labs at the NIH but + + align:start position:0% +separate left labs at the NIH but + + + align:start position:0% +separate left labs at the NIH but +something that Venter gets really + + align:start position:0% +something that Venter gets really + + + align:start position:0% +something that Venter gets really +interested in is molecular biology he + + align:start position:0% +interested in is molecular biology he + + + align:start position:0% +interested in is molecular biology he +sees that it's this field that's going + + align:start position:0% +sees that it's this field that's going + + + align:start position:0% +sees that it's this field that's going +to explode is extremely important and + + align:start position:0% +to explode is extremely important and + + + align:start position:0% +to explode is extremely important and +it's basically our path to future + + align:start position:0% +it's basically our path to future + + + align:start position:0% +it's basically our path to future +medicine so he starts to try to get + + align:start position:0% +medicine so he starts to try to get + + + align:start position:0% +medicine so he starts to try to get +funding to do molecular biology + + align:start position:0% +funding to do molecular biology + + + align:start position:0% +funding to do molecular biology +experiments and get into this field by + + align:start position:0% +experiments and get into this field by + + + align:start position:0% +experiments and get into this field by +the machines necessary and he's totally + + align:start position:0% +the machines necessary and he's totally + + + align:start position:0% +the machines necessary and he's totally +stoned all that the NIH she's basically + + align:start position:0% +stoned all that the NIH she's basically + + + align:start position:0% +stoned all that the NIH she's basically +told no you're a neuroscientist you + + align:start position:0% +told no you're a neuroscientist you + + + align:start position:0% +told no you're a neuroscientist you +can't work in this other stovepipe at + + align:start position:0% +can't work in this other stovepipe at + + + align:start position:0% +can't work in this other stovepipe at +the NIH that's just not done it won't + + align:start position:0% +the NIH that's just not done it won't + + + align:start position:0% +the NIH that's just not done it won't +work so he becomes increasingly and + + align:start position:0% +work so he becomes increasingly and + + + align:start position:0% +work so he becomes increasingly and +increasingly frustrated with the with + + align:start position:0% +increasingly frustrated with the with + + + align:start position:0% +increasingly frustrated with the with +the bureaucracy basically and he says + + align:start position:0% +the bureaucracy basically and he says + + + align:start position:0% +the bureaucracy basically and he says +that he looks around and he sees people + + align:start position:0% +that he looks around and he sees people + + + align:start position:0% +that he looks around and he sees people +who are lifers at the NIH who just go + + align:start position:0% +who are lifers at the NIH who just go + + + align:start position:0% +who are lifers at the NIH who just go +through the motions of being a scientist + + align:start position:0% +through the motions of being a scientist + + + align:start position:0% +through the motions of being a scientist +who couldn't really compete in the + + align:start position:0% +who couldn't really compete in the + + + align:start position:0% +who couldn't really compete in the +academic or the outside world so + + align:start position:0% +academic or the outside world so + + + align:start position:0% +academic or the outside world so +he does something a little maverick he + + align:start position:0% +he does something a little maverick he + + + align:start position:0% +he does something a little maverick he +creates this he he's reading about and + + align:start position:0% +creates this he he's reading about and + + + align:start position:0% +creates this he he's reading about and +hearing about the Human Genome Project + + align:start position:0% +hearing about the Human Genome Project + + + align:start position:0% +hearing about the Human Genome Project +because it's a big initiative at NIH and + + align:start position:0% +because it's a big initiative at NIH and + + + align:start position:0% +because it's a big initiative at NIH and +he decides well if they're not going to + + align:start position:0% +he decides well if they're not going to + + + align:start position:0% +he decides well if they're not going to +let me get into molecular biology and + + align:start position:0% +let me get into molecular biology and + + + align:start position:0% +let me get into molecular biology and +and sequencing the human genome then I'm + + align:start position:0% +and sequencing the human genome then I'm + + + align:start position:0% +and sequencing the human genome then I'm +going to sneak in by basically + + align:start position:0% +going to sneak in by basically + + + align:start position:0% +going to sneak in by basically +sequencing a gene involved in in in + + align:start position:0% +sequencing a gene involved in in in + + + align:start position:0% +sequencing a gene involved in in in +neurobiology so he does that and he + + align:start position:0% +neurobiology so he does that and he + + + align:start position:0% +neurobiology so he does that and he +invents this thing called est I'm not + + align:start position:0% +invents this thing called est I'm not + + + align:start position:0% +invents this thing called est I'm not +gonna get into it honestly it's such an + + align:start position:0% +gonna get into it honestly it's such an + + + align:start position:0% +gonna get into it honestly it's such an +outdated thing that I didn't even learn + + align:start position:0% +outdated thing that I didn't even learn + + + align:start position:0% +outdated thing that I didn't even learn +about it during my during my studies and + + align:start position:0% +about it during my during my studies and + + + align:start position:0% +about it during my during my studies and +then Watson and vendor have met so + + align:start position:0% +then Watson and vendor have met so + + + align:start position:0% +then Watson and vendor have met so +Watson is running the UNAM Human Genome + + align:start position:0% +Watson is running the UNAM Human Genome + + + align:start position:0% +Watson is running the UNAM Human Genome +Project at NIH right Venter comes up he + + align:start position:0% +Project at NIH right Venter comes up he + + + align:start position:0% +Project at NIH right Venter comes up he +has the sequence at this gene he he's + + align:start position:0% +has the sequence at this gene he he's + + + align:start position:0% +has the sequence at this gene he he's +made some pretty cool breakthroughs and + + align:start position:0% +made some pretty cool breakthroughs and + + + align:start position:0% +made some pretty cool breakthroughs and +goes in and meets with Watson and Watson + + align:start position:0% +goes in and meets with Watson and Watson + + + align:start position:0% +goes in and meets with Watson and Watson +gets excited about it at first but then + + align:start position:0% +gets excited about it at first but then + + + align:start position:0% +gets excited about it at first but then +craig venter goes off and kind of + + align:start position:0% +craig venter goes off and kind of + + + align:start position:0% +craig venter goes off and kind of +procures a machine sort of behind + + align:start position:0% +procures a machine sort of behind + + + align:start position:0% +procures a machine sort of behind +Watson's back because what Watson thinks + + align:start position:0% +Watson's back because what Watson thinks + + + align:start position:0% +Watson's back because what Watson thinks +and makes Watson really mad so he + + align:start position:0% +and makes Watson really mad so he + + + align:start position:0% +and makes Watson really mad so he +totally undermines and vilifies Venter + + align:start position:0% +totally undermines and vilifies Venter + + + align:start position:0% +totally undermines and vilifies Venter +in front of Congress and the US public + + align:start position:0% +in front of Congress and the US public + + + align:start position:0% +in front of Congress and the US public +because this is a huge this is a huge + + align:start position:0% +because this is a huge this is a huge + + + align:start position:0% +because this is a huge this is a huge +initiative this is like people are + + align:start position:0% +initiative this is like people are + + + align:start position:0% +initiative this is like people are +talking about it the dinner table it's a + + align:start position:0% +talking about it the dinner table it's a + + + align:start position:0% +talking about it the dinner table it's a +big deal back in the mid 1990s I would + + align:start position:0% +big deal back in the mid 1990s I would + + + align:start position:0% +big deal back in the mid 1990s I would +say so + + align:start position:0% +say so + + + align:start position:0% +say so +Watson basically doesn't like to wait + + align:start position:0% +Watson basically doesn't like to wait + + + align:start position:0% +Watson basically doesn't like to wait +Craig's doing things so let me just add + + align:start position:0% +Craig's doing things so let me just add + + + align:start position:0% +Craig's doing things so let me just add +one quick detail lilies so there's an + + align:start position:0% +one quick detail lilies so there's an + + + align:start position:0% +one quick detail lilies so there's an +issue here on what gets patented on a + + align:start position:0% +issue here on what gets patented on a + + + align:start position:0% +issue here on what gets patented on a +project like the human genome can you + + align:start position:0% +project like the human genome can you + + + align:start position:0% +project like the human genome can you +patent the genome right so this this + + align:start position:0% +patent the genome right so this this + + + align:start position:0% +patent the genome right so this this +whole issue is coming up the general + + align:start position:0% +whole issue is coming up the general + + + align:start position:0% +whole issue is coming up the general +counsel at NIH advises Venter that yes + + align:start position:0% +counsel at NIH advises Venter that yes + + + align:start position:0% +counsel at NIH advises Venter that yes +we are going to be able to patent a lot + + align:start position:0% +we are going to be able to patent a lot + + + align:start position:0% +we are going to be able to patent a lot +of this emerging genetics fields so + + align:start position:0% +of this emerging genetics fields so + + + align:start position:0% +of this emerging genetics fields so +let's protect he's a researcher for NIH + + align:start position:0% +let's protect he's a researcher for NIH + + + align:start position:0% +let's protect he's a researcher for NIH +so he's intramural researcher at NIH + + align:start position:0% +so he's intramural researcher at NIH + + + align:start position:0% +so he's intramural researcher at NIH +let's protect NIH by filing a lot + + align:start position:0% +let's protect NIH by filing a lot + + + align:start position:0% +let's protect NIH by filing a lot +the patents ourselves and the + + align:start position:0% +the patents ourselves and the + + + align:start position:0% +the patents ourselves and the +confrontation with Congress is where + + align:start position:0% +confrontation with Congress is where + + + align:start position:0% +confrontation with Congress is where +Watson attacks Venter for patenting you + + align:start position:0% +Watson attacks Venter for patenting you + + + align:start position:0% +Watson attacks Venter for patenting you +know genome technologies in other words + + align:start position:0% +know genome technologies in other words + + + align:start position:0% +know genome technologies in other words +it's not going to be available to the + + align:start position:0% +it's not going to be available to the + + + align:start position:0% +it's not going to be available to the +scientific world it's not going to be + + align:start position:0% +scientific world it's not going to be + + + align:start position:0% +scientific world it's not going to be +open based it's not going to be in the + + align:start position:0% +open based it's not going to be in the + + + align:start position:0% +open based it's not going to be in the +comments even though Venter had receipt + + align:start position:0% +comments even though Venter had receipt + + + align:start position:0% +comments even though Venter had receipt +we had been told by the General + + align:start position:0% +we had been told by the General + + + align:start position:0% +we had been told by the General +Counsel's office in NIH that that's what + + align:start position:0% +Counsel's office in NIH that that's what + + + align:start position:0% +Counsel's office in NIH that that's what +he had to do so that leads to this + + align:start position:0% +he had to do so that leads to this + + + align:start position:0% +he had to do so that leads to this +explosion of anger by Venter is that a + + align:start position:0% +explosion of anger by Venter is that a + + + align:start position:0% +explosion of anger by Venter is that a +fair summary definitely yeah from + + align:start position:0% +fair summary definitely yeah from + + + align:start position:0% +fair summary definitely yeah from +venture side of the story he says I + + align:start position:0% +venture side of the story he says I + + + align:start position:0% +venture side of the story he says I +didn't necessarily want to patent these + + align:start position:0% +didn't necessarily want to patent these + + + align:start position:0% +didn't necessarily want to patent these +genes the NIH advised me to it was their + + align:start position:0% +genes the NIH advised me to it was their + + + align:start position:0% +genes the NIH advised me to it was their +initiative and Watson used it as a way + + align:start position:0% +initiative and Watson used it as a way + + + align:start position:0% +initiative and Watson used it as a way +to undermine me in front of the American + + align:start position:0% +to undermine me in front of the American + + + align:start position:0% +to undermine me in front of the American +public because he didn't want me to use + + align:start position:0% +public because he didn't want me to use + + + align:start position:0% +public because he didn't want me to use +my technology that I had come up with so + + align:start position:0% +my technology that I had come up with so + + + align:start position:0% +my technology that I had come up with so +that's the sort of the back story Venter + + align:start position:0% +that's the sort of the back story Venter + + + align:start position:0% +that's the sort of the back story Venter +is insanely angry and he and his wife + + align:start position:0% +is insanely angry and he and his wife + + + align:start position:0% +is insanely angry and he and his wife +defect from the NIH and form Solera with + + align:start position:0% +defect from the NIH and form Solera with + + + align:start position:0% +defect from the NIH and form Solera with +the help of venture capitalists who + + align:start position:0% +the help of venture capitalists who + + + align:start position:0% +the help of venture capitalists who +later also anger Venter and that + + align:start position:0% +later also anger Venter and that + + + align:start position:0% +later also anger Venter and that +explodes and they take with them 12 men + + align:start position:0% +explodes and they take with them 12 men + + + align:start position:0% +explodes and they take with them 12 men +of their lab members from the NIH so the + + align:start position:0% +of their lab members from the NIH so the + + + align:start position:0% +of their lab members from the NIH so the +team and I think that craig Venter + + align:start position:0% +team and I think that craig Venter + + + align:start position:0% +team and I think that craig Venter +really exemplifies a great great group + + align:start position:0% +really exemplifies a great great group + + + align:start position:0% +really exemplifies a great great group +leader in that he seems able to identify + + align:start position:0% +leader in that he seems able to identify + + + align:start position:0% +leader in that he seems able to identify +talent and others so they start out with + + align:start position:0% +talent and others so they start out with + + + align:start position:0% +talent and others so they start out with +the 12 from NIH they have their island + + align:start position:0% +the 12 from NIH they have their island + + + align:start position:0% +the 12 from NIH they have their island +of Solera and the team that they start + + align:start position:0% +of Solera and the team that they start + + + align:start position:0% +of Solera and the team that they start +to form this is not including like the + + align:start position:0% +to form this is not including like the + + + align:start position:0% +to form this is not including like the +board of directors and such which also + + align:start position:0% +board of directors and such which also + + + align:start position:0% +board of directors and such which also +seem to be pretty amazing people but + + align:start position:0% +seem to be pretty amazing people but + + + align:start position:0% +seem to be pretty amazing people but +they recruit Hamiltons actually I think + + align:start position:0% +they recruit Hamiltons actually I think + + + align:start position:0% +they recruit Hamiltons actually I think +well Hamilton Smith comes on to the + + align:start position:0% +well Hamilton Smith comes on to the + + + align:start position:0% +well Hamilton Smith comes on to the +scene and he's their premier molecular + + align:start position:0% +scene and he's their premier molecular + + + align:start position:0% +scene and he's their premier molecular +biologist and he's a Nobel Prize well + + align:start position:0% +biologist and he's a Nobel Prize well + + + align:start position:0% +biologist and he's a Nobel Prize well +did he + + align:start position:0% + + + + align:start position:0% + +prior yeah yeah so I don't think any of + + align:start position:0% +prior yeah yeah so I don't think any of + + + align:start position:0% +prior yeah yeah so I don't think any of +this is actually a question I'm going to + + align:start position:0% +this is actually a question I'm going to + + + align:start position:0% +this is actually a question I'm going to +pose to the class at the end of my + + align:start position:0% +pose to the class at the end of my + + + align:start position:0% +pose to the class at the end of my +presentation I don't think anyone in + + align:start position:0% +presentation I don't think anyone in + + + align:start position:0% +presentation I don't think anyone in +this great group has one of the Nobel + + align:start position:0% +this great group has one of the Nobel + + + align:start position:0% +this great group has one of the Nobel +Prize except + + align:start position:0% +Prize except + + + align:start position:0% +Prize except +for this previously ham Smith wrote so + + align:start position:0% +for this previously ham Smith wrote so + + + align:start position:0% +for this previously ham Smith wrote so +Marshall Peterson is this computer geek + + align:start position:0% +Marshall Peterson is this computer geek + + + align:start position:0% +Marshall Peterson is this computer geek +because not only is Hamilton Smith + + align:start position:0% +because not only is Hamilton Smith + + + align:start position:0% +because not only is Hamilton Smith +literally coming up with the sequencing + + align:start position:0% +literally coming up with the sequencing + + + align:start position:0% +literally coming up with the sequencing +technology to do this this is a this is + + align:start position:0% +technology to do this this is a this is + + + align:start position:0% +technology to do this this is a this is +like 30 billion base pairs of DNA the + + align:start position:0% +like 30 billion base pairs of DNA the + + + align:start position:0% +like 30 billion base pairs of DNA the +most anyone has sequenced at this point + + align:start position:0% +most anyone has sequenced at this point + + + align:start position:0% +most anyone has sequenced at this point +is like C elegans or like a worm like + + align:start position:0% +is like C elegans or like a worm like + + + align:start position:0% +is like C elegans or like a worm like +tiny tiny genome this is a huge deal + + align:start position:0% +tiny tiny genome this is a huge deal + + + align:start position:0% +tiny tiny genome this is a huge deal +they have to come up with new sequencing + + align:start position:0% +they have to come up with new sequencing + + + align:start position:0% +they have to come up with new sequencing +technologies new ways to decode the + + align:start position:0% +technologies new ways to decode the + + + align:start position:0% +technologies new ways to decode the +sequence and new computing so they + + align:start position:0% +sequence and new computing so they + + + align:start position:0% +sequence and new computing so they +literally build the third largest + + align:start position:0% +literally build the third largest + + + align:start position:0% +literally build the third largest +computer on the planet I think the do-e + + align:start position:0% +computer on the planet I think the do-e + + + align:start position:0% +computer on the planet I think the do-e +has a larger computer and there's + + align:start position:0% +has a larger computer and there's + + + align:start position:0% +has a larger computer and there's +someone somewhere else in the world and + + align:start position:0% +someone somewhere else in the world and + + + align:start position:0% +someone somewhere else in the world and +they build this massive computing + + align:start position:0% +they build this massive computing + + + align:start position:0% +they build this massive computing +facility and then bring on gene Myers as + + align:start position:0% +facility and then bring on gene Myers as + + + align:start position:0% +facility and then bring on gene Myers as +this coder who's coming up with the + + align:start position:0% +this coder who's coming up with the + + + align:start position:0% +this coder who's coming up with the +algorithms to try to piece together all + + align:start position:0% +algorithms to try to piece together all + + + align:start position:0% +algorithms to try to piece together all +these little pieces of DNA and build up + + align:start position:0% +these little pieces of DNA and build up + + + align:start position:0% +these little pieces of DNA and build up +30 billion base sequence so in the + + align:start position:0% +30 billion base sequence so in the + + + align:start position:0% +30 billion base sequence so in the +meantime the public sector academia the + + align:start position:0% +meantime the public sector academia the + + + align:start position:0% +meantime the public sector academia the +NIH are becoming increasingly angry with + + align:start position:0% +NIH are becoming increasingly angry with + + + align:start position:0% +NIH are becoming increasingly angry with +craig Venter saying that he's he's + + align:start position:0% +craig Venter saying that he's he's + + + align:start position:0% +craig Venter saying that he's he's +defecting to the private sector and he's + + align:start position:0% +defecting to the private sector and he's + + + align:start position:0% +defecting to the private sector and he's +going after the human genome for profit + + align:start position:0% +going after the human genome for profit + + + align:start position:0% +going after the human genome for profit +Craig is saying I don't I'm not in this + + align:start position:0% +Craig is saying I don't I'm not in this + + + align:start position:0% +Craig is saying I don't I'm not in this +for profit I'm in this because we need a + + align:start position:0% +for profit I'm in this because we need a + + + align:start position:0% +for profit I'm in this because we need a +human genome so that we can promote + + align:start position:0% +human genome so that we can promote + + + align:start position:0% +human genome so that we can promote +human you know molecular biology based + + align:start position:0% +human you know molecular biology based + + + align:start position:0% +human you know molecular biology based +medicine in the meantime he sequences + + align:start position:0% +medicine in the meantime he sequences + + + align:start position:0% +medicine in the meantime he sequences +the drosophila genome and gives it its + + align:start position:0% +the drosophila genome and gives it its + + + align:start position:0% +the drosophila genome and gives it its +publishes it in science gets rich Laurie + + align:start position:0% +publishes it in science gets rich Laurie + + + align:start position:0% +publishes it in science gets rich Laurie +yeah the fruit fly genome which people + + align:start position:0% +yeah the fruit fly genome which people + + + align:start position:0% +yeah the fruit fly genome which people +have been trying to figure out what + + align:start position:0% +have been trying to figure out what + + + align:start position:0% +have been trying to figure out what +genes and fruit fly do for decades and + + align:start position:0% +genes and fruit fly do for decades and + + + align:start position:0% +genes and fruit fly do for decades and +decades and decades and so there's this + + align:start position:0% +decades and decades and so there's this + + + align:start position:0% +decades and decades and so there's this +really cool part in the interview where + + align:start position:0% +really cool part in the interview where + + + align:start position:0% +really cool part in the interview where +he talks about this community of fruit + + align:start position:0% +he talks about this community of fruit + + + align:start position:0% +he talks about this community of fruit +fly researchers who I think are kind of + + align:start position:0% +fly researchers who I think are kind of + + + align:start position:0% +fly researchers who I think are kind of +like the physics community they're + + align:start position:0% +like the physics community they're + + + align:start position:0% +like the physics community they're +pretty close-knit they have their + + align:start position:0% +pretty close-knit they have their + + + align:start position:0% +pretty close-knit they have their +conferences and they they write try to + + align:start position:0% +conferences and they they write try to + + + align:start position:0% +conferences and they they write try to +get together and and decode the fruit + + align:start position:0% +get together and and decode the fruit + + + align:start position:0% +get together and and decode the fruit +fly which they don't have the bases or + + align:start position:0% +fly which they don't have the bases or + + + align:start position:0% +fly which they don't have the bases or +the knowledge to do that yes they're + + align:start position:0% +the knowledge to do that yes they're + + + align:start position:0% +the knowledge to do that yes they're +doing it like gene by gene + + align:start position:0% +doing it like gene by gene + + + align:start position:0% +doing it like gene by gene +by Jeanne over many years and Craig + + align:start position:0% +by Jeanne over many years and Craig + + + align:start position:0% +by Jeanne over many years and Craig +decodes the the fruit fly genome and + + align:start position:0% +decodes the the fruit fly genome and + + + align:start position:0% +decodes the the fruit fly genome and +says come to Solara I have all of the + + align:start position:0% +says come to Solara I have all of the + + + align:start position:0% +says come to Solara I have all of the +information that you've been looking for + + align:start position:0% +information that you've been looking for + + + align:start position:0% +information that you've been looking for +for the past few decades and you can + + align:start position:0% +for the past few decades and you can + + + align:start position:0% +for the past few decades and you can +have it it's here so a couple says um + + align:start position:0% +have it it's here so a couple says um + + + align:start position:0% +have it it's here so a couple says um +maybe on the order of a hundred or so + + align:start position:0% +maybe on the order of a hundred or so + + + align:start position:0% +maybe on the order of a hundred or so +fruit fly researchers come and they're + + align:start position:0% +fruit fly researchers come and they're + + + align:start position:0% +fruit fly researchers come and they're +just like kids in a candy shop they stay + + align:start position:0% +just like kids in a candy shop they stay + + + align:start position:0% +just like kids in a candy shop they stay +up all hours of the night and like + + align:start position:0% +up all hours of the night and like + + + align:start position:0% +up all hours of the night and like +making these breakthroughs that they've + + align:start position:0% +making these breakthroughs that they've + + + align:start position:0% +making these breakthroughs that they've +been that they've been looking for for + + align:start position:0% +been that they've been looking for for + + + align:start position:0% +been that they've been looking for for +decades so that's pretty fun pretty cool + + align:start position:0% +decades so that's pretty fun pretty cool + + + align:start position:0% +decades so that's pretty fun pretty cool +so fruit flying sequenced NIH you would + + align:start position:0% +so fruit flying sequenced NIH you would + + + align:start position:0% +so fruit flying sequenced NIH you would +probably know more about the the + + align:start position:0% +probably know more about the the + + + align:start position:0% +probably know more about the the +interplay between Francis Collins and + + align:start position:0% +interplay between Francis Collins and + + + align:start position:0% +interplay between Francis Collins and +vinter because that I don't I'm not it's + + align:start position:0% +vinter because that I don't I'm not it's + + + align:start position:0% +vinter because that I don't I'm not it's +a little fuzzy for me I can never figure + + align:start position:0% +a little fuzzy for me I can never figure + + + align:start position:0% +a little fuzzy for me I can never figure +out if they're working together or + + align:start position:0% +out if they're working together or + + + align:start position:0% +out if they're working together or +against each other but eventually what + + align:start position:0% +against each other but eventually what + + + align:start position:0% +against each other but eventually what +happens in 2001 the NIH and the public + + align:start position:0% +happens in 2001 the NIH and the public + + + align:start position:0% +happens in 2001 the NIH and the public +like academia so people from different + + align:start position:0% +like academia so people from different + + + align:start position:0% +like academia so people from different +universities come together and publish + + align:start position:0% +universities come together and publish + + + align:start position:0% +universities come together and publish +the human genome in the journal Nature + + align:start position:0% +the human genome in the journal Nature + + + align:start position:0% +the human genome in the journal Nature +and it's like two days later salera + + align:start position:0% +and it's like two days later salera + + + align:start position:0% +and it's like two days later salera +announces same day oh it is the same day + + align:start position:0% +announces same day oh it is the same day + + + align:start position:0% +announces same day oh it is the same day +comes out in science so this is yes so + + align:start position:0% +comes out in science so this is yes so + + + align:start position:0% +comes out in science so this is yes so +there had to be I mean it's a + + align:start position:0% +there had to be I mean it's a + + + align:start position:0% +there had to be I mean it's a +fascinating story right and there's rich + + align:start position:0% +fascinating story right and there's rich + + + align:start position:0% +fascinating story right and there's rich +MIT history which MIT was on the side of + + align:start position:0% +MIT history which MIT was on the side of + + + align:start position:0% +MIT history which MIT was on the side of +NIH to see you know so Venter through + + align:start position:0% +NIH to see you know so Venter through + + + align:start position:0% +NIH to see you know so Venter through +you know a research model that was + + align:start position:0% +you know a research model that was + + + align:start position:0% +you know a research model that was +extremely focused on getting this + + align:start position:0% +extremely focused on getting this + + + align:start position:0% +extremely focused on getting this +project done right everything was to be + + align:start position:0% +project done right everything was to be + + + align:start position:0% +project done right everything was to be +organized for the project NIH is on a + + align:start position:0% +organized for the project NIH is on a + + + align:start position:0% +organized for the project NIH is on a +research model that could be described + + align:start position:0% +research model that could be described + + + align:start position:0% +research model that could be described +as let's let a thousand flowers bloom + + align:start position:0% +as let's let a thousand flowers bloom + + + align:start position:0% +as let's let a thousand flowers bloom +we'll have a lot of ro1 researchers out + + align:start position:0% +we'll have a lot of ro1 researchers out + + + align:start position:0% +we'll have a lot of ro1 researchers out +there you know eventually that will turn + + align:start position:0% +there you know eventually that will turn + + + align:start position:0% +there you know eventually that will turn +into the Human Genome Project someone + + align:start position:0% +into the Human Genome Project someone + + + align:start position:0% +into the Human Genome Project someone +made the analogy to that research model + + align:start position:0% +made the analogy to that research model + + + align:start position:0% +made the analogy to that research model +as okay if you put a whole lot of + + align:start position:0% +as okay if you put a whole lot of + + + align:start position:0% +as okay if you put a whole lot of +monkeys into a room and give them + + align:start position:0% +monkeys into a room and give them + + + align:start position:0% +monkeys into a room and give them +typewriters eventually we'll get + + align:start position:0% +typewriters eventually we'll get + + + align:start position:0% +typewriters eventually we'll get +Shakespeare right it's obviously exact + + align:start position:0% +Shakespeare right it's obviously exact + + + align:start position:0% +Shakespeare right it's obviously exact +exaggeration here but + + align:start position:0% +exaggeration here but + + + align:start position:0% +exaggeration here but +Venter with his very focused research + + align:start position:0% +Venter with his very focused research + + + align:start position:0% +Venter with his very focused research +project than these computer scientists + + align:start position:0% +project than these computer scientists + + + align:start position:0% +project than these computer scientists +and Venter himself becomes a master of + + align:start position:0% +and Venter himself becomes a master of + + + align:start position:0% +and Venter himself becomes a master of +the computers that he's working on + + align:start position:0% +the computers that he's working on + + + align:start position:0% +the computers that he's working on +building and est technology is from that + + align:start position:0% +building and est technology is from that + + + align:start position:0% +building and est technology is from that +versus a much more decentralized + + align:start position:0% +versus a much more decentralized + + + align:start position:0% +versus a much more decentralized +research operation so slowly Inayat + + align:start position:0% +research operation so slowly Inayat + + + align:start position:0% +research operation so slowly Inayat +relies it's gonna lose the race unless + + align:start position:0% +relies it's gonna lose the race unless + + + align:start position:0% +relies it's gonna lose the race unless +against its act together so they begin + + align:start position:0% +against its act together so they begin + + + align:start position:0% +against its act together so they begin +to focus on you know getting rid of the + + align:start position:0% +to focus on you know getting rid of the + + + align:start position:0% +to focus on you know getting rid of the +thousand flowers let's get down to a + + align:start position:0% +thousand flowers let's get down to a + + + align:start position:0% +thousand flowers let's get down to a +small number of focused research centers + + align:start position:0% +small number of focused research centers + + + align:start position:0% +small number of focused research centers +and it's you know it's a race really + + align:start position:0% +and it's you know it's a race really + + + align:start position:0% +and it's you know it's a race really +between who's the broad institute and + + align:start position:0% +between who's the broad institute and + + + align:start position:0% +between who's the broad institute and +head what's his name + + align:start position:0% +head what's his name + + + align:start position:0% +head what's his name +you know how can I forget Eric Lander + + align:start position:0% +you know how can I forget Eric Lander + + + align:start position:0% +you know how can I forget Eric Lander +yeah of course sorry excuse me + + align:start position:0% +yeah of course sorry excuse me + + + align:start position:0% +yeah of course sorry excuse me +so Eric Erickson mathematician he's not + + align:start position:0% +so Eric Erickson mathematician he's not + + + align:start position:0% +so Eric Erickson mathematician he's not +a life scientist right and he becomes + + align:start position:0% +a life scientist right and he becomes + + + align:start position:0% +a life scientist right and he becomes +the leader of the human Human Genome + + align:start position:0% +the leader of the human Human Genome + + + align:start position:0% +the leader of the human Human Genome +Project for NIH Collins is heading it + + align:start position:0% +Project for NIH Collins is heading it + + + align:start position:0% +Project for NIH Collins is heading it +but Eric is the one who's carrying out + + align:start position:0% +but Eric is the one who's carrying out + + + align:start position:0% +but Eric is the one who's carrying out +the computational parts of it right and + + align:start position:0% +the computational parts of it right and + + + align:start position:0% +the computational parts of it right and +they do it in cooperation with the + + align:start position:0% +they do it in cooperation with the + + + align:start position:0% +they do it in cooperation with the +Department of Energy super computer labs + + align:start position:0% +Department of Energy super computer labs + + + align:start position:0% +Department of Energy super computer labs +because they need their own + + align:start position:0% +because they need their own + + + align:start position:0% +because they need their own +supercomputing capability ventures built + + align:start position:0% +supercomputing capability ventures built + + + align:start position:0% +supercomputing capability ventures built +is NIH uses do e so this race is ongoing + + align:start position:0% +is NIH uses do e so this race is ongoing + + + align:start position:0% +is NIH uses do e so this race is ongoing +the NIH crowd is attacking Venter + + align:start position:0% +the NIH crowd is attacking Venter + + + align:start position:0% +the NIH crowd is attacking Venter +constantly for essentially trying to + + align:start position:0% +constantly for essentially trying to + + + align:start position:0% +constantly for essentially trying to +profit from patenting the genome that's + + align:start position:0% +profit from patenting the genome that's + + + align:start position:0% +profit from patenting the genome that's +the complaint that he's gonna take this + + align:start position:0% +the complaint that he's gonna take this + + + align:start position:0% +the complaint that he's gonna take this +critical scientific advance few critical + + align:start position:0% +critical scientific advance few critical + + + align:start position:0% +critical scientific advance few critical +to the future of medicine and take it + + align:start position:0% +to the future of medicine and take it + + + align:start position:0% +to the future of medicine and take it +out of circulation and access to science + + align:start position:0% +out of circulation and access to science + + + align:start position:0% +out of circulation and access to science +and patent it and prevent anybody from + + align:start position:0% +and patent it and prevent anybody from + + + align:start position:0% +and patent it and prevent anybody from +using it that's the case being made + + align:start position:0% +using it that's the case being made + + + align:start position:0% +using it that's the case being made +against him it's pretty far in reality + + align:start position:0% +against him it's pretty far in reality + + + align:start position:0% +against him it's pretty far in reality +from what the truth is but that's the + + align:start position:0% +from what the truth is but that's the + + + align:start position:0% +from what the truth is but that's the +case being made and + + align:start position:0% + + + + align:start position:0% + +Eric and the NIH team are gradually they + + align:start position:0% +Eric and the NIH team are gradually they + + + align:start position:0% +Eric and the NIH team are gradually they +are using some Avengers technology the + + align:start position:0% +are using some Avengers technology the + + + align:start position:0% +are using some Avengers technology the +originating certainly many of their own + + align:start position:0% +originating certainly many of their own + + + align:start position:0% +originating certainly many of their own +they're within range so at that point a + + align:start position:0% +they're within range so at that point a + + + align:start position:0% +they're within range so at that point a +negotiated truth is arranged so that + + align:start position:0% +negotiated truth is arranged so that + + + align:start position:0% +negotiated truth is arranged so that +nobody gets embarrassed here right and + + align:start position:0% +nobody gets embarrassed here right and + + + align:start position:0% +nobody gets embarrassed here right and +the real worry was that NIH would lose + + align:start position:0% +the real worry was that NIH would lose + + + align:start position:0% +the real worry was that NIH would lose +the race right so eventually Venter has + + align:start position:0% +the race right so eventually Venter has + + + align:start position:0% +the race right so eventually Venter has +prevailed on to declare a tie and each + + align:start position:0% +prevailed on to declare a tie and each + + + align:start position:0% +prevailed on to declare a tie and each +side will publish in the two major + + align:start position:0% +side will publish in the two major + + + align:start position:0% +side will publish in the two major +scientific publications their version of + + align:start position:0% +scientific publications their version of + + + align:start position:0% +scientific publications their version of +the genome and that's in fact what + + align:start position:0% +the genome and that's in fact what + + + align:start position:0% +the genome and that's in fact what +occurs it's go ahead one is that in this + + align:start position:0% +occurs it's go ahead one is that in this + + + align:start position:0% +occurs it's go ahead one is that in this +interview Venter says that he finds out + + align:start position:0% +interview Venter says that he finds out + + + align:start position:0% +interview Venter says that he finds out +that Francis Collins the head of the NIH + + align:start position:0% +that Francis Collins the head of the NIH + + + align:start position:0% +that Francis Collins the head of the NIH +has not has budgeted less than half of + + align:start position:0% +has not has budgeted less than half of + + + align:start position:0% +has not has budgeted less than half of +what it's going to take at their current + + align:start position:0% +what it's going to take at their current + + + align:start position:0% +what it's going to take at their current +rate to complete the human genome so in + + align:start position:0% +rate to complete the human genome so in + + + align:start position:0% +rate to complete the human genome so in +his mind Collins has no intention of + + align:start position:0% +his mind Collins has no intention of + + + align:start position:0% +his mind Collins has no intention of +really completing it and they can't as + + align:start position:0% +really completing it and they can't as + + + align:start position:0% +really completing it and they can't as +the way things stood the other point I + + align:start position:0% +the way things stood the other point I + + + align:start position:0% +the way things stood the other point I +wanted to make is that the niña like + + align:start position:0% +wanted to make is that the niña like + + + align:start position:0% +wanted to make is that the niña like +Venters enemies and adversaries keep on + + align:start position:0% +Venters enemies and adversaries keep on + + + align:start position:0% +Venters enemies and adversaries keep on +barding him and the public by saying + + align:start position:0% +barding him and the public by saying + + + align:start position:0% +barding him and the public by saying +he's gonna profit off the human genome + + align:start position:0% +he's gonna profit off the human genome + + + align:start position:0% +he's gonna profit off the human genome +and there is a little there's actually a + + align:start position:0% +and there is a little there's actually a + + + align:start position:0% +and there is a little there's actually a +lot of friction between + + align:start position:0% +lot of friction between + + + align:start position:0% +lot of friction between +vinter and has been sure capitalists + + align:start position:0% +vinter and has been sure capitalists + + + align:start position:0% +vinter and has been sure capitalists +because he wants to publish publish + + align:start position:0% +because he wants to publish publish + + + align:start position:0% +because he wants to publish publish +publish publish the findings that + + align:start position:0% +publish publish the findings that + + + align:start position:0% +publish publish the findings that +they're making so that other people can + + align:start position:0% +they're making so that other people can + + + align:start position:0% +they're making so that other people can +utilize them and the venture capitalists + + align:start position:0% +utilize them and the venture capitalists + + + align:start position:0% +utilize them and the venture capitalists +keep saying no we don't want you can't + + align:start position:0% +keep saying no we don't want you can't + + + align:start position:0% +keep saying no we don't want you can't +do that you can't do that it's private + + align:start position:0% +do that you can't do that it's private + + + align:start position:0% +do that you can't do that it's private +we we want to patent etc so there's that + + align:start position:0% +we we want to patent etc so there's that + + + align:start position:0% +we we want to patent etc so there's that +friction going on so yes eventually + + align:start position:0% +friction going on so yes eventually + + + align:start position:0% +friction going on so yes eventually +published at the same time salera + + align:start position:0% +published at the same time salera + + + align:start position:0% +published at the same time salera +actually Venter is both quits and is + + align:start position:0% +actually Venter is both quits and is + + + align:start position:0% +actually Venter is both quits and is +fired from Solera + + align:start position:0% +fired from Solera + + + align:start position:0% +fired from Solera +at the same time inventors mind he was + + align:start position:0% +at the same time inventors mind he was + + + align:start position:0% +at the same time inventors mind he was +about to quit anyway + + align:start position:0% +about to quit anyway + + + align:start position:0% +about to quit anyway +but yeah he was basically asked to leave + + align:start position:0% +but yeah he was basically asked to leave + + + align:start position:0% +but yeah he was basically asked to leave +on a Monday morning yeah yeah there are + + align:start position:0% +on a Monday morning yeah yeah there are + + + align:start position:0% +on a Monday morning yeah yeah there are +a lot of parallels but Martine he's + + align:start position:0% +a lot of parallels but Martine he's + + + align:start position:0% +a lot of parallels but Martine he's +different right he creates this group + + align:start position:0% +different right he creates this group + + + align:start position:0% +different right he creates this group +originally at his NIH lab it's basically + + align:start position:0% +originally at his NIH lab it's basically + + + align:start position:0% +originally at his NIH lab it's basically +still with him right right this is not + + align:start position:0% +still with him right right this is not + + + align:start position:0% +still with him right right this is not +Joe + + align:start position:0% +Joe + + + align:start position:0% +Joe +abrasiveness right and screaming this is + + align:start position:0% +abrasiveness right and screaming this is + + + align:start position:0% +abrasiveness right and screaming this is +somebody who is really he's a pretty + + align:start position:0% +somebody who is really he's a pretty + + + align:start position:0% +somebody who is really he's a pretty +charismatic figure I've spent a little + + align:start position:0% +charismatic figure I've spent a little + + + align:start position:0% +charismatic figure I've spent a little +time with him and you know he is able to + + align:start position:0% +time with him and you know he is able to + + + align:start position:0% +time with him and you know he is able to +keep over absolutely remarkable team + + align:start position:0% +keep over absolutely remarkable team + + + align:start position:0% +keep over absolutely remarkable team +together for a remarkably long period of + + align:start position:0% +together for a remarkably long period of + + + align:start position:0% +together for a remarkably long period of +time so it's a different personal + + align:start position:0% +time so it's a different personal + + + align:start position:0% +time so it's a different personal +atmosphere a different kind of + + align:start position:0% +atmosphere a different kind of + + + align:start position:0% +atmosphere a different kind of +leadership style but you know remember + + align:start position:0% +leadership style but you know remember + + + align:start position:0% +leadership style but you know remember +what it must have been like I mean he + + align:start position:0% +what it must have been like I mean he + + + align:start position:0% +what it must have been like I mean he +comes back from you know the Vietnam War + + align:start position:0% +comes back from you know the Vietnam War + + + align:start position:0% +comes back from you know the Vietnam War +full of you know Navy and Marine Corps + + align:start position:0% +full of you know Navy and Marine Corps + + + align:start position:0% +full of you know Navy and Marine Corps +tattoos right he's you know a veteran of + + align:start position:0% +tattoos right he's you know a veteran of + + + align:start position:0% +tattoos right he's you know a veteran of +this you know ghastly war and he's been + + align:start position:0% +this you know ghastly war and he's been + + + align:start position:0% +this you know ghastly war and he's been +he's seen some of the worst outcomes + + align:start position:0% +he's seen some of the worst outcomes + + + align:start position:0% +he's seen some of the worst outcomes +running a whole hospital wing virtually + + align:start position:0% +running a whole hospital wing virtually + + + align:start position:0% +running a whole hospital wing virtually +on his own and Danang and sees two men + + align:start position:0% +on his own and Danang and sees two men + + + align:start position:0% +on his own and Danang and sees two men +you know death and loss of life and + + align:start position:0% +you know death and loss of life and + + + align:start position:0% +you know death and loss of life and +trying to save life firsthand in a very + + align:start position:0% +trying to save life firsthand in a very + + + align:start position:0% +trying to save life firsthand in a very +personal kind of way he's completely + + align:start position:0% +personal kind of way he's completely + + + align:start position:0% +personal kind of way he's completely +different than the kind of culture of + + align:start position:0% +different than the kind of culture of + + + align:start position:0% +different than the kind of culture of +NIH you know he's up from a + + align:start position:0% +NIH you know he's up from a + + + align:start position:0% +NIH you know he's up from a +working-class military family and it's + + align:start position:0% +working-class military family and it's + + + align:start position:0% +working-class military family and it's +just a different world that he's been + + align:start position:0% +just a different world that he's been + + + align:start position:0% +just a different world that he's been +exposed to and he doesn't get along with + + align:start position:0% +exposed to and he doesn't get along with + + + align:start position:0% +exposed to and he doesn't get along with +this kind of you know established + + align:start position:0% +this kind of you know established + + + align:start position:0% +this kind of you know established +liberal community of scientists and NIH + + align:start position:0% +liberal community of scientists and NIH + + + align:start position:0% +liberal community of scientists and NIH +so that's part of what's going on here I + + align:start position:0% +so that's part of what's going on here I + + + align:start position:0% +so that's part of what's going on here I +think Willie it just he's just a really + + align:start position:0% +think Willie it just he's just a really + + + align:start position:0% +think Willie it just he's just a really +different character pushing him at the + + align:start position:0% +different character pushing him at the + + + align:start position:0% +different character pushing him at the +NIH is and through that throughout the + + align:start position:0% +NIH is and through that throughout the + + + align:start position:0% +NIH is and through that throughout the +human genome project is decode the human + + align:start position:0% +human genome project is decode the human + + + align:start position:0% +human genome project is decode the human +genome so we don't see the situation or + + align:start position:0% +genome so we don't see the situation or + + + align:start position:0% +genome so we don't see the situation or +the things that he saw in the hospital + + align:start position:0% +the things that he saw in the hospital + + + align:start position:0% +the things that he saw in the hospital +at done it doesn't he thinks that modern + + align:start position:0% +at done it doesn't he thinks that modern + + + align:start position:0% +at done it doesn't he thinks that modern +medicine should eradicate those sorts of + + align:start position:0% +medicine should eradicate those sorts of + + + align:start position:0% +medicine should eradicate those sorts of +injuries and really his vision is + + align:start position:0% +injuries and really his vision is + + + align:start position:0% +injuries and really his vision is +synthetic biology we regrow we grow + + align:start position:0% +synthetic biology we regrow we grow + + + align:start position:0% +synthetic biology we regrow we grow +everything synthetically we grow human + + align:start position:0% +everything synthetically we grow human + + + align:start position:0% +everything synthetically we grow human +limbs become you know he's very + + align:start position:0% +limbs become you know he's very + + + align:start position:0% +limbs become you know he's very +forward-thinking as far as the medical + + align:start position:0% +forward-thinking as far as the medical + + + align:start position:0% +forward-thinking as far as the medical +uses of knowing genetics I just question + + align:start position:0% +uses of knowing genetics I just question + + + align:start position:0% +uses of knowing genetics I just question +like so what exactly were they trying to + + align:start position:0% +like so what exactly were they trying to + + + align:start position:0% +like so what exactly were they trying to +kind underside + + align:start position:0% +kind underside + + + align:start position:0% +kind underside +lots of things so I think that one worry + + align:start position:0% +lots of things so I think that one worry + + + align:start position:0% +lots of things so I think that one worry +was that his invention his Craig's + + align:start position:0% +was that his invention his Craig's + + + align:start position:0% +was that his invention his Craig's +method of est would be patented itself + + align:start position:0% +method of est would be patented itself + + + align:start position:0% +method of est would be patented itself +and it's an extremely it was for well + + align:start position:0% +and it's an extremely it was for well + + + align:start position:0% +and it's an extremely it was for well +some areas of biology still use it not + + align:start position:0% +some areas of biology still use it not + + + align:start position:0% +some areas of biology still use it not +my particular field but a lot of areas + + align:start position:0% +my particular field but a lot of areas + + + align:start position:0% +my particular field but a lot of areas +in biology still use it and if it were + + align:start position:0% +in biology still use it and if it were + + + align:start position:0% +in biology still use it and if it were +that they wouldn't be able to obviously + + align:start position:0% +that they wouldn't be able to obviously + + + align:start position:0% +that they wouldn't be able to obviously +so it's an it's widely applicable its + + align:start position:0% +so it's an it's widely applicable its + + + align:start position:0% +so it's an it's widely applicable its +technique and there was there was + + align:start position:0% +technique and there was there was + + + align:start position:0% +technique and there was there was +worried that he would try to patent EST + + align:start position:0% +worried that he would try to patent EST + + + align:start position:0% +worried that he would try to patent EST +or there might have I think there was a + + align:start position:0% +or there might have I think there was a + + + align:start position:0% +or there might have I think there was a +patent in and the NIH pulled it or + + align:start position:0% +patent in and the NIH pulled it or + + + align:start position:0% +patent in and the NIH pulled it or +something like that with so much + + align:start position:0% +something like that with so much + + + align:start position:0% +something like that with so much +negative press there were a couple of + + align:start position:0% +negative press there were a couple of + + + align:start position:0% +negative press there were a couple of +other things up for patent maybe but I + + align:start position:0% +other things up for patent maybe but I + + + align:start position:0% +other things up for patent maybe but I +don't know the specifics why don't we + + align:start position:0% +don't know the specifics why don't we + + + align:start position:0% +don't know the specifics why don't we +get into some questions okay oh yeah so + + align:start position:0% +get into some questions okay oh yeah so + + + align:start position:0% +get into some questions okay oh yeah so +what does he do + + align:start position:0% +what does he do + + + align:start position:0% +what does he do +so Solera goes boom with the dot-com + + align:start position:0% +so Solera goes boom with the dot-com + + + align:start position:0% +so Solera goes boom with the dot-com +bubbles like worth fifteen billion + + align:start position:0% +bubbles like worth fifteen billion + + + align:start position:0% +bubbles like worth fifteen billion +dollars in an inflating the stock goes + + align:start position:0% +dollars in an inflating the stock goes + + + align:start position:0% +dollars in an inflating the stock goes +from five hundred bucks to six dollars + + align:start position:0% +from five hundred bucks to six dollars + + + align:start position:0% +from five hundred bucks to six dollars +at that point Craig had already left one + + align:start position:0% +at that point Craig had already left one + + + align:start position:0% +at that point Craig had already left one +of the reasons that the stock dropped so + + align:start position:0% +of the reasons that the stock dropped so + + + align:start position:0% +of the reasons that the stock dropped so +drastically was because people found out + + align:start position:0% +drastically was because people found out + + + align:start position:0% +drastically was because people found out +that Craig left so now well not now but + + align:start position:0% +that Craig left so now well not now but + + + align:start position:0% +that Craig left so now well not now but +then he decides well I'm gonna do my own + + align:start position:0% +then he decides well I'm gonna do my own + + + align:start position:0% +then he decides well I'm gonna do my own +science and I'm gonna sequence the + + align:start position:0% +science and I'm gonna sequence the + + + align:start position:0% +science and I'm gonna sequence the +entire ocean I'm done with the human + + align:start position:0% +entire ocean I'm done with the human + + + align:start position:0% +entire ocean I'm done with the human +genome now I'm gonna go to the ocean so + + align:start position:0% +genome now I'm gonna go to the ocean so + + + align:start position:0% +genome now I'm gonna go to the ocean so +he gets on this 100-foot yacht the + + align:start position:0% +he gets on this 100-foot yacht the + + + align:start position:0% +he gets on this 100-foot yacht the +sorcerer or two and a couple of people I + + align:start position:0% +sorcerer or two and a couple of people I + + + align:start position:0% +sorcerer or two and a couple of people I +talk with a with a woman who's a + + align:start position:0% +talk with a with a woman who's a + + + align:start position:0% +talk with a with a woman who's a +professor at USC who was on some of the + + align:start position:0% +professor at USC who was on some of the + + + align:start position:0% +professor at USC who was on some of the +sorcerer legs of the journey and then + + align:start position:0% +sorcerer legs of the journey and then + + + align:start position:0% +sorcerer legs of the journey and then +her husband John Heidelberg is on he was + + align:start position:0% +her husband John Heidelberg is on he was + + + align:start position:0% +her husband John Heidelberg is on he was +on my thesis committee so he's the third + + align:start position:0% +on my thesis committee so he's the third + + + align:start position:0% +on my thesis committee so he's the third +author on this paper and they have lots + + align:start position:0% +author on this paper and they have lots + + + align:start position:0% +author on this paper and they have lots +of fun craig stories as well and one of + + align:start position:0% +of fun craig stories as well and one of + + + align:start position:0% +of fun craig stories as well and one of +the i think one of the themes throughout + + align:start position:0% +the i think one of the themes throughout + + + align:start position:0% +the i think one of the themes throughout +the great groups is that there are a lot + + align:start position:0% +the great groups is that there are a lot + + + align:start position:0% +the great groups is that there are a lot +of partiers like if they're not doing + + align:start position:0% +of partiers like if they're not doing + + + align:start position:0% +of partiers like if they're not doing +really crazy good science they're + + align:start position:0% +really crazy good science they're + + + align:start position:0% +really crazy good science they're +partying hey doc and they just have a + + align:start position:0% +partying hey doc and they just have a + + + align:start position:0% +partying hey doc and they just have a +huge party so then he finishes sailing + + align:start position:0% +huge party so then he finishes sailing + + + align:start position:0% +huge party so then he finishes sailing +around the world a couple of times in + + align:start position:0% +around the world a couple of times in + + + align:start position:0% +around the world a couple of times in +sequencing all the bacteria in the ocean + + align:start position:0% +sequencing all the bacteria in the ocean + + + align:start position:0% +sequencing all the bacteria in the ocean +and sets up the JCB i which is located + + align:start position:0% +and sets up the JCB i which is located + + + align:start position:0% +and sets up the JCB i which is located +in la jolla right next to his alma mater + + align:start position:0% +in la jolla right next to his alma mater + + + align:start position:0% +in la jolla right next to his alma mater +UCSD + + align:start position:0% +UCSD + + + align:start position:0% +UCSD +that's a picture Craig from a few years + + align:start position:0% +that's a picture Craig from a few years + + + align:start position:0% +that's a picture Craig from a few years +ago so to conclude a few Joyce quotes + + align:start position:0% +ago so to conclude a few Joyce quotes + + + align:start position:0% +ago so to conclude a few Joyce quotes +from Craig I've gotten some pretty nice + + align:start position:0% +from Craig I've gotten some pretty nice + + + align:start position:0% +from Craig I've gotten some pretty nice +awards and I'm having trouble finding + + align:start position:0% +awards and I'm having trouble finding + + + align:start position:0% +awards and I'm having trouble finding +places to put them all and then one + + align:start position:0% +places to put them all and then one + + + align:start position:0% +places to put them all and then one +that's more pertinent to this class is + + align:start position:0% +that's more pertinent to this class is + + + align:start position:0% +that's more pertinent to this class is +the environment has fallen to the + + align:start position:0% +the environment has fallen to the + + + align:start position:0% +the environment has fallen to the +wayside in politics + + align:start position:0% +wayside in politics + + + align:start position:0% +wayside in politics +lastly oh I wanted to go over Venters + + align:start position:0% +lastly oh I wanted to go over Venters + + + align:start position:0% +lastly oh I wanted to go over Venters +thoughts on innovation but that's not + + align:start position:0% +thoughts on innovation but that's not + + + align:start position:0% +thoughts on innovation but that's not +we're getting quotes on time so that's + + align:start position:0% +we're getting quotes on time so that's + + + align:start position:0% +we're getting quotes on time so that's +not really necessary these are better + + align:start position:0% +not really necessary these are better + + + align:start position:0% +not really necessary these are better +how about some questions okay + + align:start position:0% +how about some questions okay + + + align:start position:0% +how about some questions okay +um so show up I wanted to see in the + + align:start position:0% +um so show up I wanted to see in the + + + align:start position:0% +um so show up I wanted to see in the +class by show of hands who thinks that + + align:start position:0% +class by show of hands who thinks that + + + align:start position:0% +class by show of hands who thinks that +Venter or maybe a couple of people + + align:start position:0% +Venter or maybe a couple of people + + + align:start position:0% +Venter or maybe a couple of people +within his group I mean they decoded the + + align:start position:0% +within his group I mean they decoded the + + + align:start position:0% +within his group I mean they decoded the +human genome which was just the amount + + align:start position:0% +human genome which was just the amount + + + align:start position:0% +human genome which was just the amount +of new technologies that they came up + + align:start position:0% +of new technologies that they came up + + + align:start position:0% +of new technologies that they came up +with both in computing and molecular + + align:start position:0% +with both in computing and molecular + + + align:start position:0% +with both in computing and molecular +biology in order to do that are + + align:start position:0% +biology in order to do that are + + + align:start position:0% +biology in order to do that are +astounding so who in here would say like + + align:start position:0% +astounding so who in here would say like + + + align:start position:0% +astounding so who in here would say like +he should be a Nobel Prize winner for + + align:start position:0% +he should be a Nobel Prize winner for + + + align:start position:0% +he should be a Nobel Prize winner for +people in his group + + align:start position:0% +people in his group + + + align:start position:0% +people in his group +I'm sure there's got to be some other + + align:start position:0% +I'm sure there's got to be some other + + + align:start position:0% +I'm sure there's got to be some other +equivalent biology centered award + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% + + + + align:start position:0% + +there's like a watson-crick award and he + + align:start position:0% +there's like a watson-crick award and he + + + align:start position:0% +there's like a watson-crick award and he +wins what we started oh other stuff was + + align:start position:0% +wins what we started oh other stuff was + + + align:start position:0% +wins what we started oh other stuff was +based off of shrinkers what his life + + align:start position:0% +based off of shrinkers what his life + + + align:start position:0% +based off of shrinkers what his life +[Music] + + align:start position:0% + + + + align:start position:0% + +question where do they call it decoding + + align:start position:0% +question where do they call it decoding + + + align:start position:0% +question where do they call it decoding +and not encoding the human genome mmm I + + align:start position:0% +and not encoding the human genome mmm I + + + align:start position:0% +and not encoding the human genome mmm I +think it would be called decoding + + align:start position:0% +think it would be called decoding + + + align:start position:0% +think it would be called decoding +because what this looks like when you + + align:start position:0% +because what this looks like when you + + + align:start position:0% +because what this looks like when you +actually read the basis is fluorescent + + align:start position:0% +actually read the basis is fluorescent + + + align:start position:0% +actually read the basis is fluorescent +dye so you have to read you have to + + align:start position:0% +dye so you have to read you have to + + + align:start position:0% +dye so you have to read you have to +decode the fluorescent signature in + + align:start position:0% +decode the fluorescent signature in + + + align:start position:0% +decode the fluorescent signature in +order to get the base pairs so it's not + + align:start position:0% +order to get the base pairs so it's not + + + align:start position:0% +order to get the base pairs so it's not +about it's about we're so evaluating the + + align:start position:0% +about it's about we're so evaluating the + + + align:start position:0% +about it's about we're so evaluating the +results than it is about sort of + + align:start position:0% +results than it is about sort of + + + align:start position:0% +results than it is about sort of +expressing the results yeah + + align:start position:0% + + + + align:start position:0% + +one thing about this effort here at me + + align:start position:0% +one thing about this effort here at me + + + align:start position:0% +one thing about this effort here at me +you have to get a sense of how + + align:start position:0% +you have to get a sense of how + + + align:start position:0% +you have to get a sense of how +transformational this seemed in the + + align:start position:0% +transformational this seemed in the + + + align:start position:0% +transformational this seemed in the +nineteen nineties it was really quite + + align:start position:0% +nineteen nineties it was really quite + + + align:start position:0% +nineteen nineties it was really quite +amazing but this was one of the great + + align:start position:0% +amazing but this was one of the great + + + align:start position:0% +amazing but this was one of the great +scientific competitions of all time + + align:start position:0% +scientific competitions of all time + + + align:start position:0% +scientific competitions of all time +right this incredible race to do that to + + align:start position:0% +right this incredible race to do that to + + + align:start position:0% +right this incredible race to do that to +decode the genome and this is being you + + align:start position:0% +decode the genome and this is being you + + + align:start position:0% +decode the genome and this is being you +know this is a major news story right + + align:start position:0% +know this is a major news story right + + + align:start position:0% +know this is a major news story right +and Francis Collins has a Harley + + align:start position:0% +and Francis Collins has a Harley + + + align:start position:0% +and Francis Collins has a Harley +motorcycle and sings on a blues band and + + align:start position:0% +motorcycle and sings on a blues band and + + + align:start position:0% +motorcycle and sings on a blues band and +you know he has his own you know fast he + + align:start position:0% +you know he has his own you know fast he + + + align:start position:0% +you know he has his own you know fast he +still rides his motorcycle into work in + + align:start position:0% +still rides his motorcycle into work in + + + align:start position:0% +still rides his motorcycle into work in +nih Venter is a yachtsman who buys these + + align:start position:0% +nih Venter is a yachtsman who buys these + + + align:start position:0% +nih Venter is a yachtsman who buys these +wild incredibly dangerous you know + + align:start position:0% +wild incredibly dangerous you know + + + align:start position:0% +wild incredibly dangerous you know +sailboats and loves that the kind of + + align:start position:0% +sailboats and loves that the kind of + + + align:start position:0% +sailboats and loves that the kind of +wild adventure of you know being you + + align:start position:0% +wild adventure of you know being you + + + align:start position:0% +wild adventure of you know being you +know tempestuous sea close to the wind + + align:start position:0% +know tempestuous sea close to the wind + + + align:start position:0% +know tempestuous sea close to the wind +and near capsized danger with these you + + align:start position:0% +and near capsized danger with these you + + + align:start position:0% +and near capsized danger with these you +know monsters sailboats so both of them + + align:start position:0% +know monsters sailboats so both of them + + + align:start position:0% +know monsters sailboats so both of them +have their kind of wild side here + + align:start position:0% +have their kind of wild side here + + + align:start position:0% +have their kind of wild side here +there's no question about it but this + + align:start position:0% +there's no question about it but this + + + align:start position:0% +there's no question about it but this +competition captures the public + + align:start position:0% +competition captures the public + + + align:start position:0% +competition captures the public +imagination and it's a very important + + align:start position:0% +imagination and it's a very important + + + align:start position:0% +imagination and it's a very important +race because the race forces incredible + + align:start position:0% +race because the race forces incredible + + + align:start position:0% +race because the race forces incredible +speed in the project so what had I + + align:start position:0% +speed in the project so what had I + + + align:start position:0% +speed in the project so what had I +probably been originally viewed as a 40 + + align:start position:0% +probably been originally viewed as a 40 + + + align:start position:0% +probably been originally viewed as a 40 +year project gets you know knocked down + + align:start position:0% +year project gets you know knocked down + + + align:start position:0% +year project gets you know knocked down +to well less than a decade by the time + + align:start position:0% +to well less than a decade by the time + + + align:start position:0% +to well less than a decade by the time +these characters you know kind of + + align:start position:0% +these characters you know kind of + + + align:start position:0% +these characters you know kind of +complete the race and agree to a truce + + align:start position:0% +complete the race and agree to a truce + + + align:start position:0% +complete the race and agree to a truce +by publishing on the same day and in + + align:start position:0% +by publishing on the same day and in + + + align:start position:0% +by publishing on the same day and in +turn I was working on in the Senate you + + align:start position:0% +turn I was working on in the Senate you + + + align:start position:0% +turn I was working on in the Senate you +know while this is all going on and you + + align:start position:0% +know while this is all going on and you + + + align:start position:0% +know while this is all going on and you +know the public is getting a sense gee + + align:start position:0% +know the public is getting a sense gee + + + align:start position:0% +know the public is getting a sense gee +we really are getting fairly close to + + align:start position:0% +we really are getting fairly close to + + + align:start position:0% +we really are getting fairly close to +this one obviously fundamental answers + + align:start position:0% +this one obviously fundamental answers + + + align:start position:0% +this one obviously fundamental answers +here and when two US senators senator + + align:start position:0% +here and when two US senators senator + + + align:start position:0% +here and when two US senators senator +Specter and Senator Harkin from + + align:start position:0% +Specter and Senator Harkin from + + + align:start position:0% +Specter and Senator Harkin from +Pennsylvania in Iowa respectively were + + align:start position:0% +Pennsylvania in Iowa respectively were + + + align:start position:0% +Pennsylvania in Iowa respectively were +cheran ranking on the Appropriations + + align:start position:0% +cheran ranking on the Appropriations + + + align:start position:0% +cheran ranking on the Appropriations +Subcommittee that handles NIH they + + align:start position:0% +Subcommittee that handles NIH they + + + align:start position:0% +Subcommittee that handles NIH they +actually there's a in the Clinton years + + align:start position:0% +actually there's a in the Clinton years + + + align:start position:0% +actually there's a in the Clinton years +because the IT revolution is creating a + + align:start position:0% +because the IT revolution is creating a + + + align:start position:0% +because the IT revolution is creating a +lot of extra tax revenue we're balancing + + align:start position:0% +lot of extra tax revenue we're balancing + + + align:start position:0% +lot of extra tax revenue we're balancing +the budget so there's revenue on one of + + align:start position:0% +the budget so there's revenue on one of + + + align:start position:0% +the budget so there's revenue on one of +those rare moments there's revenue in + + align:start position:0% +those rare moments there's revenue in + + + align:start position:0% +those rare moments there's revenue in +the federal government + + align:start position:0% +the federal government + + + align:start position:0% +the federal government +Spectre and heart can go down and take + + align:start position:0% +Spectre and heart can go down and take + + + align:start position:0% +Spectre and heart can go down and take +the revenue and that's what doubles NIH + + align:start position:0% +the revenue and that's what doubles NIH + + + align:start position:0% +the revenue and that's what doubles NIH +and nobody says they're wrong because of + + align:start position:0% +and nobody says they're wrong because of + + + align:start position:0% +and nobody says they're wrong because of +the excitement that this race to get to + + align:start position:0% +the excitement that this race to get to + + + align:start position:0% +the excitement that this race to get to +the genome is created and what it's what + + align:start position:0% +the genome is created and what it's what + + + align:start position:0% +the genome is created and what it's what +its scientific possibilities are so sure + + align:start position:0% +its scientific possibilities are so sure + + + align:start position:0% +its scientific possibilities are so sure +there's a whole political effort to + + align:start position:0% +there's a whole political effort to + + + align:start position:0% +there's a whole political effort to +radically increase NIH funding but the + + align:start position:0% +radically increase NIH funding but the + + + align:start position:0% +radically increase NIH funding but the +enabler here is the public excitement + + align:start position:0% +enabler here is the public excitement + + + align:start position:0% +enabler here is the public excitement +around the genome race and what its + + align:start position:0% +around the genome race and what its + + + align:start position:0% +around the genome race and what its +possibilities might be to accomplish so + + align:start position:0% +possibilities might be to accomplish so + + + align:start position:0% +possibilities might be to accomplish so +this has enduring kind of lasting + + align:start position:0% +this has enduring kind of lasting + + + align:start position:0% +this has enduring kind of lasting +effects that spill over in many kind of + + align:start position:0% +effects that spill over in many kind of + + + align:start position:0% +effects that spill over in many kind of +ways into the into the life science + + align:start position:0% +ways into the into the life science + + + align:start position:0% +ways into the into the life science +arena next question now but you want to + + align:start position:0% +arena next question now but you want to + + + align:start position:0% +arena next question now but you want to +pose a couple of questions and one then + + align:start position:0% +pose a couple of questions and one then + + + align:start position:0% +pose a couple of questions and one then +we'll wrap things up yeah one of the + + align:start position:0% +we'll wrap things up yeah one of the + + + align:start position:0% +we'll wrap things up yeah one of the +things I was thinking about while + + align:start position:0% +things I was thinking about while + + + align:start position:0% +things I was thinking about while +reading this and the other readings in + + align:start position:0% +reading this and the other readings in + + + align:start position:0% +reading this and the other readings in +the class is that Venter seems to form + + align:start position:0% +the class is that Venter seems to form + + + align:start position:0% +the class is that Venter seems to form +and dissolve and reform multiple great + + align:start position:0% +and dissolve and reform multiple great + + + align:start position:0% +and dissolve and reform multiple great +groups throughout his lifetime like from + + align:start position:0% +groups throughout his lifetime like from + + + align:start position:0% +groups throughout his lifetime like from +the 80s to present day and in thinking + + align:start position:0% +the 80s to present day and in thinking + + + align:start position:0% +the 80s to present day and in thinking +about other great lilies only changing + + align:start position:0% +about other great lilies only changing + + + align:start position:0% +about other great lilies only changing +the formal structure the team really + + align:start position:0% +the formal structure the team really + + + align:start position:0% +the formal structure the team really +follows him from one organizational + + align:start position:0% +follows him from one organizational + + + align:start position:0% +follows him from one organizational +model to another + + align:start position:0% +model to another + + + align:start position:0% +model to another +that's true anyway so do we think that + + align:start position:0% +that's true anyway so do we think that + + + align:start position:0% +that's true anyway so do we think that +most great group leaders have a great + + align:start position:0% +most great group leaders have a great + + + align:start position:0% +most great group leaders have a great +one great group and then that's their + + align:start position:0% +one great group and then that's their + + + align:start position:0% +one great group and then that's their +like their opus they don't go on and + + align:start position:0% +like their opus they don't go on and + + + align:start position:0% +like their opus they don't go on and +they have one mission like Apple because + + align:start position:0% +they have one mission like Apple because + + + align:start position:0% +they have one mission like Apple because +there is the Mac team so that's a + + align:start position:0% +there is the Mac team so that's a + + + align:start position:0% +there is the Mac team so that's a +certain product so if it's a once + + align:start position:0% +certain product so if it's a once + + + align:start position:0% +certain product so if it's a once +particular problem you have a group and + + align:start position:0% +particular problem you have a group and + + + align:start position:0% +particular problem you have a group and +then you can choose to take a belief + + align:start position:0% +then you can choose to take a belief + + + align:start position:0% +then you can choose to take a belief +after + + align:start position:0% +after + + + align:start position:0% +after +the Apple is remarkable for its ability + + align:start position:0% +the Apple is remarkable for its ability + + + align:start position:0% +the Apple is remarkable for its ability +to go from one major technology launch + + align:start position:0% +to go from one major technology launch + + + align:start position:0% +to go from one major technology launch +to another in sequence it's really very + + align:start position:0% +to another in sequence it's really very + + + align:start position:0% +to another in sequence it's really very +hard and very difficult and + + align:start position:0% +hard and very difficult and + + + align:start position:0% +hard and very difficult and +interestingly it hasn't happened since + + align:start position:0% +interestingly it hasn't happened since + + + align:start position:0% +interestingly it hasn't happened since +Jobs type that we know + + align:start position:0% + + + + align:start position:0% + +the hybrid apples kind of sorry to die + + align:start position:0% +the hybrid apples kind of sorry to die + + + align:start position:0% +the hybrid apples kind of sorry to die +down there's there's a model industry I + + align:start position:0% +down there's there's a model industry I + + + align:start position:0% +down there's there's a model industry I +mean how does a big company innovate + + align:start position:0% +mean how does a big company innovate + + + align:start position:0% +mean how does a big company innovate +it's a terribly difficult problem right + + align:start position:0% +it's a terribly difficult problem right + + + align:start position:0% +it's a terribly difficult problem right +there this suits the other bureaucracy + + align:start position:0% +there this suits the other bureaucracy + + + align:start position:0% +there this suits the other bureaucracy +Lockheed is kind of noted as the + + align:start position:0% +Lockheed is kind of noted as the + + + align:start position:0% +Lockheed is kind of noted as the +experimenter here they they set up + + align:start position:0% +experimenter here they they set up + + + align:start position:0% +experimenter here they they set up +something called the skunk works as a + + align:start position:0% +something called the skunk works as a + + + align:start position:0% +something called the skunk works as a +completely side separate organization on + + align:start position:0% +completely side separate organization on + + + align:start position:0% +completely side separate organization on +a protected island with a bridge back to + + align:start position:0% +a protected island with a bridge back to + + + align:start position:0% +a protected island with a bridge back to +the Lockheed management and they do + + align:start position:0% +the Lockheed management and they do + + + align:start position:0% +the Lockheed management and they do +remarkable advances in in Aeronautics + + align:start position:0% +remarkable advances in in Aeronautics + + + align:start position:0% +remarkable advances in in Aeronautics +and aerospace so they do the they do the + + align:start position:0% +and aerospace so they do the they do the + + + align:start position:0% +and aerospace so they do the they do the +u2 they do the sr-71 blackbird which + + align:start position:0% +u2 they do the sr-71 blackbird which + + + align:start position:0% +u2 they do the sr-71 blackbird which +many people who this day think is the + + align:start position:0% +many people who this day think is the + + + align:start position:0% +many people who this day think is the +most remarkable plane ever built but + + align:start position:0% +most remarkable plane ever built but + + + align:start position:0% +most remarkable plane ever built but +then a whole sequence of other aircraft + + align:start position:0% +then a whole sequence of other aircraft + + + align:start position:0% +then a whole sequence of other aircraft +and they do stealth right they're the + + align:start position:0% +and they do stealth right they're the + + + align:start position:0% +and they do stealth right they're the +implementers of a lot of the stealth + + align:start position:0% +implementers of a lot of the stealth + + + align:start position:0% +implementers of a lot of the stealth +technology so that's an example of how a + + align:start position:0% +technology so that's an example of how a + + + align:start position:0% +technology so that's an example of how a +corporation is able to create an entity + + align:start position:0% +corporation is able to create an entity + + + align:start position:0% +corporation is able to create an entity +that can move through a series of great + + align:start position:0% +that can move through a series of great + + + align:start position:0% +that can move through a series of great +groups and keep innovating that's kind + + align:start position:0% +groups and keep innovating that's kind + + + align:start position:0% +groups and keep innovating that's kind +of held up as a kind of iconic model so + + align:start position:0% +of held up as a kind of iconic model so + + + align:start position:0% +of held up as a kind of iconic model so +it is possible so when you're the small + + align:start position:0% +it is possible so when you're the small + + + align:start position:0% +it is possible so when you're the small +companies that you all set up become + + align:start position:0% +companies that you all set up become + + + align:start position:0% +companies that you all set up become +major corporations you know read read + + align:start position:0% +major corporations you know read read + + + align:start position:0% +major corporations you know read read +about skunk works because that'll be + + align:start position:0% +about skunk works because that'll be + + + align:start position:0% +about skunk works because that'll be +your clue to continue to survival it + + align:start position:0% +your clue to continue to survival it + + + align:start position:0% +your clue to continue to survival it +wasn't fun + + align:start position:0% +wasn't fun + + + align:start position:0% +wasn't fun +fights analog devices just up the street + + align:start position:0% + + + + align:start position:0% + +we how about a closing thought for us + + align:start position:0% +we how about a closing thought for us + + + align:start position:0% +we how about a closing thought for us +about this amazing crowd let's see I + + align:start position:0% +about this amazing crowd let's see I + + + align:start position:0% +about this amazing crowd let's see I +think that Craig is right when he says + + align:start position:0% +think that Craig is right when he says + + + align:start position:0% +think that Craig is right when he says +you have to take risks you have to take + + align:start position:0% +you have to take risks you have to take + + + align:start position:0% +you have to take risks you have to take +risks or else you're not gonna do + + align:start position:0% +risks or else you're not gonna do + + + align:start position:0% +risks or else you're not gonna do +anything worth writing about and that's + + align:start position:0% +anything worth writing about and that's + + + align:start position:0% +anything worth writing about and that's +a great way to close \ No newline at end of file diff --git a/dFF2DuEv-2c.txt b/dFF2DuEv-2c.txt new file mode 100644 index 0000000000000000000000000000000000000000..7d991036fb1fb7cee4031e0b322142dceb423315 --- /dev/null +++ b/dFF2DuEv-2c.txt @@ -0,0 +1,16891 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT open courseware continue + + align:start position:0% +will help MIT open courseware continue + + + align:start position:0% +will help MIT open courseware continue +to offer highquality educational + + align:start position:0% +to offer highquality educational + + + align:start position:0% +to offer highquality educational +resources for free to make a donation or + + align:start position:0% +resources for free to make a donation or + + + align:start position:0% +resources for free to make a donation or +view additional materials from hundreds + + align:start position:0% +view additional materials from hundreds + + + align:start position:0% +view additional materials from hundreds +of MIT courses visit MIT opencourseware + + align:start position:0% +of MIT courses visit MIT opencourseware + + + align:start position:0% +of MIT courses visit MIT opencourseware +at + + align:start position:0% + + + + align:start position:0% + +ocw.mit.edu what we're going to be doing + + align:start position:0% +ocw.mit.edu what we're going to be doing + + + align:start position:0% +ocw.mit.edu what we're going to be doing +over the next few days um uh today and + + align:start position:0% +over the next few days um uh today and + + + align:start position:0% +over the next few days um uh today and +on Tuesday is really diving into the uh + + align:start position:0% +on Tuesday is really diving into the uh + + + align:start position:0% +on Tuesday is really diving into the uh +device fundamentals and then on Tuesday + + align:start position:0% +device fundamentals and then on Tuesday + + + align:start position:0% +device fundamentals and then on Tuesday +the materials fundamentals of how a + + align:start position:0% +the materials fundamentals of how a + + + align:start position:0% +the materials fundamentals of how a +solar cell device really works and uh + + align:start position:0% +solar cell device really works and uh + + + align:start position:0% +solar cell device really works and uh +what we've done so far is uh skimmed + + align:start position:0% +what we've done so far is uh skimmed + + + align:start position:0% +what we've done so far is uh skimmed +along at a very high level um + + align:start position:0% +along at a very high level um + + + align:start position:0% +along at a very high level um +using only the necessary physics and + + align:start position:0% +using only the necessary physics and + + + align:start position:0% +using only the necessary physics and +nothing more to describe how a solar + + align:start position:0% +nothing more to describe how a solar + + + align:start position:0% +nothing more to describe how a solar +cell works uh because we want to give + + align:start position:0% +cell works uh because we want to give + + + align:start position:0% +cell works uh because we want to give +you an intuition about solar cell device + + align:start position:0% +you an intuition about solar cell device + + + align:start position:0% +you an intuition about solar cell device +operation uh the alternative way of + + align:start position:0% +operation uh the alternative way of + + + align:start position:0% +operation uh the alternative way of +teaching PV is that we go heavy on the + + align:start position:0% +teaching PV is that we go heavy on the + + + align:start position:0% +teaching PV is that we go heavy on the +device physics up front front uh you're + + align:start position:0% +device physics up front front uh you're + + + align:start position:0% +device physics up front front uh you're +completely overloaded your RAM is is is + + align:start position:0% +completely overloaded your RAM is is is + + + align:start position:0% +completely overloaded your RAM is is is +completely full uh and by the time we + + align:start position:0% +completely full uh and by the time we + + + align:start position:0% +completely full uh and by the time we +actually get to IV curves you you're + + align:start position:0% +actually get to IV curves you you're + + + align:start position:0% +actually get to IV curves you you're +completely lost so hopefully you have + + align:start position:0% +completely lost so hopefully you have + + + align:start position:0% +completely lost so hopefully you have +some intuitive sense now about how a PV + + align:start position:0% +some intuitive sense now about how a PV + + + align:start position:0% +some intuitive sense now about how a PV +device works now we're going to be doing + + align:start position:0% +device works now we're going to be doing + + + align:start position:0% +device works now we're going to be doing +some deep dives into some advanced + + align:start position:0% +some deep dives into some advanced + + + align:start position:0% +some deep dives into some advanced +concepts so that we really uh have a + + align:start position:0% +concepts so that we really uh have a + + + align:start position:0% +concepts so that we really uh have a +sophisticated understanding of how a + + align:start position:0% +sophisticated understanding of how a + + + align:start position:0% +sophisticated understanding of how a +solar cell works so uh let's dive into + + align:start position:0% +solar cell works so uh let's dive into + + + align:start position:0% +solar cell works so uh let's dive into +uh the lecture material toward a 1D + + align:start position:0% +uh the lecture material toward a 1D + + + align:start position:0% +uh the lecture material toward a 1D +device model we want to be able to + + align:start position:0% +device model we want to be able to + + + align:start position:0% +device model we want to be able to +create a one-dimensional model that + + align:start position:0% +create a one-dimensional model that + + + align:start position:0% +create a one-dimensional model that +describes how a solar cell operates so + + align:start position:0% +describes how a solar cell operates so + + + align:start position:0% +describes how a solar cell operates so +we want to capture all of the necessary + + align:start position:0% +we want to capture all of the necessary + + + align:start position:0% +we want to capture all of the necessary +physics uh from the from the materials + + align:start position:0% +physics uh from the from the materials + + + align:start position:0% +physics uh from the from the materials +and the device uh to describe the IV + + align:start position:0% +and the device uh to describe the IV + + + align:start position:0% +and the device uh to describe the IV +characteristics of a solar cell so what + + align:start position:0% +characteristics of a solar cell so what + + + align:start position:0% +characteristics of a solar cell so what +we'll do at the very beginning is start + + align:start position:0% +we'll do at the very beginning is start + + + align:start position:0% +we'll do at the very beginning is start +with a little bit of nomenclature so + + align:start position:0% +with a little bit of nomenclature so + + + align:start position:0% +with a little bit of nomenclature so +that we understand what we're talking + + align:start position:0% +that we understand what we're talking + + + align:start position:0% +that we understand what we're talking +about in terms of energy conversion + + align:start position:0% +about in terms of energy conversion + + + align:start position:0% +about in terms of energy conversion +efficiency and Quantum efficiency and + + align:start position:0% +efficiency and Quantum efficiency and + + + align:start position:0% +efficiency and Quantum efficiency and +then we'll start describing the + + align:start position:0% +then we'll start describing the + + + align:start position:0% +then we'll start describing the +different parameters that affect uh + + align:start position:0% +different parameters that affect uh + + + align:start position:0% +different parameters that affect uh +energy conversion efficiency and Quantum + + align:start position:0% +energy conversion efficiency and Quantum + + + align:start position:0% +energy conversion efficiency and Quantum +efficiency here so one of the first key + + align:start position:0% +efficiency here so one of the first key + + + align:start position:0% +efficiency here so one of the first key +Concepts that's very very important to + + align:start position:0% +Concepts that's very very important to + + + align:start position:0% +Concepts that's very very important to +understand is that energy conversion + + align:start position:0% +understand is that energy conversion + + + align:start position:0% +understand is that energy conversion +efficiency is not the same thing as + + align:start position:0% +efficiency is not the same thing as + + + align:start position:0% +efficiency is not the same thing as +quantum efficiency you'll hear these two + + align:start position:0% +quantum efficiency you'll hear these two + + + align:start position:0% +quantum efficiency you'll hear these two +terms used quite frequently in the PB + + align:start position:0% +terms used quite frequently in the PB + + + align:start position:0% +terms used quite frequently in the PB +Community uh now I would say we're we're + + align:start position:0% +Community uh now I would say we're we're + + + align:start position:0% +Community uh now I would say we're we're +really starting to get sophisticated + + align:start position:0% +really starting to get sophisticated + + + align:start position:0% +really starting to get sophisticated +about their use in the very beginning of + + align:start position:0% +about their use in the very beginning of + + + align:start position:0% +about their use in the very beginning of +the of the field well let's put it this + + align:start position:0% +the of the field well let's put it this + + + align:start position:0% +the of the field well let's put it this +way in the third wave of PV which began + + align:start position:0% +way in the third wave of PV which began + + + align:start position:0% +way in the third wave of PV which began +at around late 1990s early 2000s um + + align:start position:0% +at around late 1990s early 2000s um + + + align:start position:0% +at around late 1990s early 2000s um +which was uh really when say some of the + + align:start position:0% +which was uh really when say some of the + + + align:start position:0% +which was uh really when say some of the +novel materials uh Quantum dot-based + + align:start position:0% +novel materials uh Quantum dot-based + + + align:start position:0% +novel materials uh Quantum dot-based +solar cells uh some Modern organic + + align:start position:0% +solar cells uh some Modern organic + + + align:start position:0% +solar cells uh some Modern organic +material-based solar cells really + + align:start position:0% +material-based solar cells really + + + align:start position:0% +material-based solar cells really +started to take off there wasn't that + + align:start position:0% +started to take off there wasn't that + + + align:start position:0% +started to take off there wasn't that +sophistic at of of understanding of of + + align:start position:0% +sophistic at of of understanding of of + + + align:start position:0% +sophistic at of of understanding of of +some of the nomenclature in PV and so + + align:start position:0% +some of the nomenclature in PV and so + + + align:start position:0% +some of the nomenclature in PV and so +terms were used in a confusing way when + + align:start position:0% +terms were used in a confusing way when + + + align:start position:0% +terms were used in a confusing way when +you read some of the papers back from + + align:start position:0% +you read some of the papers back from + + + align:start position:0% +you read some of the papers back from +the early 2000s you might pick up on + + align:start position:0% +the early 2000s you might pick up on + + + align:start position:0% +the early 2000s you might pick up on +some of this uh and so that's why I have + + align:start position:0% +some of this uh and so that's why I have + + + align:start position:0% +some of this uh and so that's why I have +this slide right here describing very + + align:start position:0% +this slide right here describing very + + + align:start position:0% +this slide right here describing very +clearly what is quantum efficiency and + + align:start position:0% +clearly what is quantum efficiency and + + + align:start position:0% +clearly what is quantum efficiency and +what is energy conversion efficiency um + + align:start position:0% +what is energy conversion efficiency um + + + align:start position:0% +what is energy conversion efficiency um +so energy conversion efficiency is + + align:start position:0% +so energy conversion efficiency is + + + align:start position:0% +so energy conversion efficiency is +pretty easy to understand we've been + + align:start position:0% +pretty easy to understand we've been + + + align:start position:0% +pretty easy to understand we've been +talking about that all class we've been + + align:start position:0% +talking about that all class we've been + + + align:start position:0% +talking about that all class we've been +talking about how a photon comes in with + + align:start position:0% +talking about how a photon comes in with + + + align:start position:0% +talking about how a photon comes in with +a certain amount of energy and you + + align:start position:0% +a certain amount of energy and you + + + align:start position:0% +a certain amount of energy and you +extract electrons from your solar cell + + align:start position:0% +extract electrons from your solar cell + + + align:start position:0% +extract electrons from your solar cell +device that have a certain amount of + + align:start position:0% +device that have a certain amount of + + + align:start position:0% +device that have a certain amount of +energy and that ratio would be the + + align:start position:0% +energy and that ratio would be the + + + align:start position:0% +energy and that ratio would be the +energy conversion efficiency is + + align:start position:0% +energy conversion efficiency is + + + align:start position:0% +energy conversion efficiency is +essentially uh the energy coming out + + align:start position:0% +essentially uh the energy coming out + + + align:start position:0% +essentially uh the energy coming out +divided by the energy going in so if for + + align:start position:0% +divided by the energy going in so if for + + + align:start position:0% +divided by the energy going in so if for +example one Photon comes in with three + + align:start position:0% +example one Photon comes in with three + + + align:start position:0% +example one Photon comes in with three +EV and generates an electron whole pair + + align:start position:0% +EV and generates an electron whole pair + + + align:start position:0% +EV and generates an electron whole pair +which is then extracted from the device + + align:start position:0% +which is then extracted from the device + + + align:start position:0% +which is then extracted from the device +with a voltage of say uh6 volts uh we + + align:start position:0% +with a voltage of say uh6 volts uh we + + + align:start position:0% +with a voltage of say uh6 volts uh we +would have an energy conversion + + align:start position:0% +would have an energy conversion + + + align:start position:0% +would have an energy conversion +efficiency less than one somewhere + + align:start position:0% +efficiency less than one somewhere + + + align:start position:0% +efficiency less than one somewhere +around 15% or so whereas if we uh if we + + align:start position:0% +around 15% or so whereas if we uh if we + + + align:start position:0% +around 15% or so whereas if we uh if we +uh looked at Quantum efficiency and + + align:start position:0% +uh looked at Quantum efficiency and + + + align:start position:0% +uh looked at Quantum efficiency and +Define quantum efficiency as the number + + align:start position:0% +Define quantum efficiency as the number + + + align:start position:0% +Define quantum efficiency as the number +of electrons out per incident Photon + + align:start position:0% +of electrons out per incident Photon + + + align:start position:0% +of electrons out per incident Photon +that means if we have one Photon coming + + align:start position:0% +that means if we have one Photon coming + + + align:start position:0% +that means if we have one Photon coming +in and one electron coming out of our + + align:start position:0% +in and one electron coming out of our + + + align:start position:0% +in and one electron coming out of our +device we have a Quantum efficiency of + + align:start position:0% +device we have a Quantum efficiency of + + + align:start position:0% +device we have a Quantum efficiency of +one or 100% so Quantum efficiency can be + + align:start position:0% +one or 100% so Quantum efficiency can be + + + align:start position:0% +one or 100% so Quantum efficiency can be +thought of as collection efficiency it + + align:start position:0% +thought of as collection efficiency it + + + align:start position:0% +thought of as collection efficiency it +means how many electron whole pairs were + + align:start position:0% +means how many electron whole pairs were + + + align:start position:0% +means how many electron whole pairs were +generated inside of the device and how + + align:start position:0% +generated inside of the device and how + + + align:start position:0% +generated inside of the device and how +many were collected coming out of the + + align:start position:0% +many were collected coming out of the + + + align:start position:0% +many were collected coming out of the +device um there's a little bit more T in + + align:start position:0% +device um there's a little bit more T in + + + align:start position:0% +device um there's a little bit more T in +that dealing with reflectivity off the + + align:start position:0% +that dealing with reflectivity off the + + + align:start position:0% +that dealing with reflectivity off the +surface I'll get to that in a slide or + + align:start position:0% +surface I'll get to that in a slide or + + + align:start position:0% +surface I'll get to that in a slide or +two but it can be thought of roughly as + + align:start position:0% +two but it can be thought of roughly as + + + align:start position:0% +two but it can be thought of roughly as +collection efficiency as whereas energy + + align:start position:0% +collection efficiency as whereas energy + + + align:start position:0% +collection efficiency as whereas energy +conversion efficiency is really what you + + align:start position:0% +conversion efficiency is really what you + + + align:start position:0% +conversion efficiency is really what you +think of in terms of thermodynamic + + align:start position:0% +think of in terms of thermodynamic + + + align:start position:0% +think of in terms of thermodynamic +efficiency of a device + + align:start position:0% +efficiency of a device + + + align:start position:0% +efficiency of a device +why is this important well uh there are + + align:start position:0% +why is this important well uh there are + + + align:start position:0% +why is this important well uh there are +papers out there this is an old one I + + align:start position:0% +papers out there this is an old one I + + + align:start position:0% +papers out there this is an old one I +think in in in nature materials if I'm + + align:start position:0% +think in in in nature materials if I'm + + + align:start position:0% +think in in in nature materials if I'm +not mistaken um that that uh started + + align:start position:0% +not mistaken um that that uh started + + + align:start position:0% +not mistaken um that that uh started +using a bunch of terms right so under 0 + + align:start position:0% +using a bunch of terms right so under 0 + + + align:start position:0% +using a bunch of terms right so under 0 +or under five volts bias an illumination + + align:start position:0% +or under five volts bias an illumination + + + align:start position:0% +or under five volts bias an illumination +from a 975 nanometer laser so nothing + + align:start position:0% +from a 975 nanometer laser so nothing + + + align:start position:0% +from a 975 nanometer laser so nothing +like a polychromatic solar Spectrum this + + align:start position:0% +like a polychromatic solar Spectrum this + + + align:start position:0% +like a polychromatic solar Spectrum this +is a monochromatic light source our + + align:start position:0% +is a monochromatic light source our + + + align:start position:0% +is a monochromatic light source our +detectors show an internal Quantum + + align:start position:0% +detectors show an internal Quantum + + + align:start position:0% +detectors show an internal Quantum +efficiency of + + align:start position:0% +efficiency of + + + align:start position:0% +efficiency of +3% the photovoltaic response under this + + align:start position:0% +3% the photovoltaic response under this + + + align:start position:0% +3% the photovoltaic response under this +monochromatic light results in a maximum + + align:start position:0% +monochromatic light results in a maximum + + + align:start position:0% +monochromatic light results in a maximum +open circuit voltage of so and so a + + align:start position:0% +open circuit voltage of so and so a + + + align:start position:0% +open circuit voltage of so and so a +short circuit current of 350 nanoamps + + align:start position:0% +short circuit current of 350 nanoamps + + + align:start position:0% +short circuit current of 350 nanoamps +very very tiny and a short circuit + + align:start position:0% +very very tiny and a short circuit + + + align:start position:0% +very very tiny and a short circuit +current internal Quantum efficiency of + + align:start position:0% + + + + align:start position:0% + +0.006% so what they're talking about + + align:start position:0% +0.006% so what they're talking about + + + align:start position:0% +0.006% so what they're talking about +here is a a Quantum efficiency right of + + align:start position:0% +here is a a Quantum efficiency right of + + + align:start position:0% +here is a a Quantum efficiency right of +0.06% as we've already done just by the + + align:start position:0% +0.06% as we've already done just by the + + + align:start position:0% +0.06% as we've already done just by the +simple example of the 3v photon coming + + align:start position:0% +simple example of the 3v photon coming + + + align:start position:0% +simple example of the 3v photon coming +in exciting electron whole pair um + + align:start position:0% +in exciting electron whole pair um + + + align:start position:0% +in exciting electron whole pair um +Quantum efficiency of one but energy + + align:start position:0% +Quantum efficiency of one but energy + + + align:start position:0% +Quantum efficiency of one but energy +conversion efficiency below 20% we can + + align:start position:0% +conversion efficiency below 20% we can + + + align:start position:0% +conversion efficiency below 20% we can +already guess that the energy conversion + + align:start position:0% +already guess that the energy conversion + + + align:start position:0% +already guess that the energy conversion +efficiency of a device like this even + + align:start position:0% +efficiency of a device like this even + + + align:start position:0% +efficiency of a device like this even +for monochromatic light is going to be + + align:start position:0% +for monochromatic light is going to be + + + align:start position:0% +for monochromatic light is going to be +very low right so what what the reason + + align:start position:0% +very low right so what what the reason + + + align:start position:0% +very low right so what what the reason +I'm I'm highlighting this abstract right + + align:start position:0% +I'm I'm highlighting this abstract right + + + align:start position:0% +I'm I'm highlighting this abstract right +here is because it's a great example of + + align:start position:0% +here is because it's a great example of + + + align:start position:0% +here is because it's a great example of +um the uh plethora of different terms + + align:start position:0% +um the uh plethora of different terms + + + align:start position:0% +um the uh plethora of different terms +that you could find in reading a paper + + align:start position:0% +that you could find in reading a paper + + + align:start position:0% +that you could find in reading a paper +right and if you focus on just a few of + + align:start position:0% +right and if you focus on just a few of + + + align:start position:0% +right and if you focus on just a few of +them uh like oh uh 3% wow that's awesome + + align:start position:0% +them uh like oh uh 3% wow that's awesome + + + align:start position:0% +them uh like oh uh 3% wow that's awesome +3% device efficiency no it's not energy + + align:start position:0% +3% device efficiency no it's not energy + + + align:start position:0% +3% device efficiency no it's not energy +conversion efficiency that's the uh + + align:start position:0% +conversion efficiency that's the uh + + + align:start position:0% +conversion efficiency that's the uh +Quantum efficiency under a very specific + + align:start position:0% +Quantum efficiency under a very specific + + + align:start position:0% +Quantum efficiency under a very specific +bias condition reverse bias it's like a + + align:start position:0% +bias condition reverse bias it's like a + + + align:start position:0% +bias condition reverse bias it's like a +photod detector not a not a solar cell + + align:start position:0% +photod detector not a not a solar cell + + + align:start position:0% +photod detector not a not a solar cell +not under forward bias conditions okay + + align:start position:0% +not under forward bias conditions okay + + + align:start position:0% +not under forward bias conditions okay +so what does this really mean this + + align:start position:0% +so what does this really mean this + + + align:start position:0% +so what does this really mean this +0.006% uh shortcircuit internal Quantum + + align:start position:0% +0.006% uh shortcircuit internal Quantum + + + align:start position:0% +0.006% uh shortcircuit internal Quantum +efficiency well we defined our energy + + align:start position:0% +efficiency well we defined our energy + + + align:start position:0% +efficiency well we defined our energy +conversion efficiency or solar + + align:start position:0% +conversion efficiency or solar + + + align:start position:0% +conversion efficiency or solar +conversion efficiency as power out + + align:start position:0% +conversion efficiency as power out + + + align:start position:0% +conversion efficiency as power out +divided by power in uh that was done in + + align:start position:0% +divided by power in uh that was done in + + + align:start position:0% +divided by power in uh that was done in +the previous lectures um the power out + + align:start position:0% +the previous lectures um the power out + + + align:start position:0% +the previous lectures um the power out +would be the power and the uh the the + + align:start position:0% +would be the power and the uh the the + + + align:start position:0% +would be the power and the uh the the +current and the voltage product at the + + align:start position:0% +current and the voltage product at the + + + align:start position:0% +current and the voltage product at the +maximum power point divided by the solar + + align:start position:0% +maximum power point divided by the solar + + + align:start position:0% +maximum power point divided by the solar +flux coming in um and that would be + + align:start position:0% +flux coming in um and that would be + + + align:start position:0% +flux coming in um and that would be +equivalent to the fill Factor times the + + align:start position:0% +equivalent to the fill Factor times the + + + align:start position:0% +equivalent to the fill Factor times the +short circuit current times the open + + align:start position:0% +short circuit current times the open + + + align:start position:0% +short circuit current times the open +circuit voltage and typical values for + + align:start position:0% +circuit voltage and typical values for + + + align:start position:0% +circuit voltage and typical values for +energy conversion efficiency are in the + + align:start position:0% +energy conversion efficiency are in the + + + align:start position:0% +energy conversion efficiency are in the +12 to 20% range I would say uh maybe + + align:start position:0% +12 to 20% range I would say uh maybe + + + align:start position:0% +12 to 20% range I would say uh maybe +less than 10% for emerging Technologies + + align:start position:0% +less than 10% for emerging Technologies + + + align:start position:0% +less than 10% for emerging Technologies +but but these are are typical values and + + align:start position:0% +but but these are are typical values and + + + align:start position:0% +but but these are are typical values and +um the uh solar flux the illumination + + align:start position:0% +um the uh solar flux the illumination + + + align:start position:0% +um the uh solar flux the illumination +intensity might vary as well but + + align:start position:0% +intensity might vary as well but + + + align:start position:0% +intensity might vary as well but +typically we talk about one sun or am + + align:start position:0% +typically we talk about one sun or am + + + align:start position:0% +typically we talk about one sun or am +1.5 uh illumination condition right so + + align:start position:0% +1.5 uh illumination condition right so + + + align:start position:0% +1.5 uh illumination condition right so +that's our our Spectrum at at am 1.5 + + align:start position:0% +that's our our Spectrum at at am 1.5 + + + align:start position:0% +that's our our Spectrum at at am 1.5 +conditions what we did on homework + + align:start position:0% +conditions what we did on homework + + + align:start position:0% +conditions what we did on homework +number one now the quantum efficiency uh + + align:start position:0% +number one now the quantum efficiency uh + + + align:start position:0% +number one now the quantum efficiency uh +has two flavors one we'll call external + + align:start position:0% +has two flavors one we'll call external + + + align:start position:0% +has two flavors one we'll call external +Quantum efficiency and the other + + align:start position:0% +Quantum efficiency and the other + + + align:start position:0% +Quantum efficiency and the other +internal Quantum efficiency and they're + + align:start position:0% +internal Quantum efficiency and they're + + + align:start position:0% +internal Quantum efficiency and they're +basically the difference between them is + + align:start position:0% +basically the difference between them is + + + align:start position:0% +basically the difference between them is +the reflectance off the front surface of + + align:start position:0% +the reflectance off the front surface of + + + align:start position:0% +the reflectance off the front surface of +the device the internal Quantum + + align:start position:0% +the device the internal Quantum + + + align:start position:0% +the device the internal Quantum +efficiency um uh essentially factors out + + align:start position:0% +efficiency um uh essentially factors out + + + align:start position:0% +efficiency um uh essentially factors out +the reflectance the external Quantum + + align:start position:0% +the reflectance the external Quantum + + + align:start position:0% +the reflectance the external Quantum +efficiency is really um taking + + align:start position:0% +efficiency is really um taking + + + align:start position:0% +efficiency is really um taking +reflectance into account as well so + + align:start position:0% +reflectance into account as well so + + + align:start position:0% +reflectance into account as well so +external Quantum efficiency is defined + + align:start position:0% +external Quantum efficiency is defined + + + align:start position:0% +external Quantum efficiency is defined +as electrons out per photons toward the + + align:start position:0% +as electrons out per photons toward the + + + align:start position:0% +as electrons out per photons toward the +device we say photons in but this is + + align:start position:0% +device we say photons in but this is + + + align:start position:0% +device we say photons in but this is +really how many photons are impingent + + align:start position:0% +really how many photons are impingent + + + align:start position:0% +really how many photons are impingent +upon the device itself some of those + + align:start position:0% +upon the device itself some of those + + + align:start position:0% +upon the device itself some of those +photons will be reflected off the front + + align:start position:0% +photons will be reflected off the front + + + align:start position:0% +photons will be reflected off the front +surface other photons will go into the + + align:start position:0% +surface other photons will go into the + + + align:start position:0% +surface other photons will go into the +device and generate electron hold pairs + + align:start position:0% +device and generate electron hold pairs + + + align:start position:0% +device and generate electron hold pairs +or some will go straight through the + + align:start position:0% +or some will go straight through the + + + align:start position:0% +or some will go straight through the +device and be absorbed in the back + + align:start position:0% +device and be absorbed in the back + + + align:start position:0% +device and be absorbed in the back +surface or so forth so the eqe external + + align:start position:0% +surface or so forth so the eqe external + + + align:start position:0% +surface or so forth so the eqe external +Quantum efficiency typical Peak values + + align:start position:0% +Quantum efficiency typical Peak values + + + align:start position:0% +Quantum efficiency typical Peak values +range between 60 and 90% depending on + + align:start position:0% +range between 60 and 90% depending on + + + align:start position:0% +range between 60 and 90% depending on +the reflectivity uh for moderate + + align:start position:0% +the reflectivity uh for moderate + + + align:start position:0% +the reflectivity uh for moderate +efficiency devices + + align:start position:0% +efficiency devices + + + align:start position:0% +efficiency devices +right so the reason Peak values range + + align:start position:0% +right so the reason Peak values range + + + align:start position:0% +right so the reason Peak values range +from 60 to 90 is because there's going + + align:start position:0% +from 60 to 90 is because there's going + + + align:start position:0% +from 60 to 90 is because there's going +to be some band of wavelengths at which + + align:start position:0% +to be some band of wavelengths at which + + + align:start position:0% +to be some band of wavelengths at which +the solar cell really responds well it's + + align:start position:0% +the solar cell really responds well it's + + + align:start position:0% +the solar cell really responds well it's +really efficient at converting that + + align:start position:0% +really efficient at converting that + + + align:start position:0% +really efficient at converting that +those photons into electron hole Pairs + + align:start position:0% +those photons into electron hole Pairs + + + align:start position:0% +those photons into electron hole Pairs +and where the Sun instead of a beautiful + + align:start position:0% +and where the Sun instead of a beautiful + + + align:start position:0% +and where the Sun instead of a beautiful +polychromatic black body emission Source + + align:start position:0% +polychromatic black body emission Source + + + align:start position:0% +polychromatic black body emission Source +if the sun were a monochromatic light + + align:start position:0% +if the sun were a monochromatic light + + + align:start position:0% +if the sun were a monochromatic light +source tuned to that particular + + align:start position:0% +source tuned to that particular + + + align:start position:0% +source tuned to that particular +wavelength the solar cell would be + + align:start position:0% +wavelength the solar cell would be + + + align:start position:0% +wavelength the solar cell would be +Wicked efficient but it's not so um this + + align:start position:0% +Wicked efficient but it's not so um this + + + align:start position:0% +Wicked efficient but it's not so um this +is this is why e Q is is an interesting + + align:start position:0% +is this is why e Q is is an interesting + + + align:start position:0% +is this is why e Q is is an interesting +parameter because it tells you the + + align:start position:0% +parameter because it tells you the + + + align:start position:0% +parameter because it tells you the +response of the solar cell to different + + align:start position:0% +response of the solar cell to different + + + align:start position:0% +response of the solar cell to different +spectral conditions and that's why we + + align:start position:0% +spectral conditions and that's why we + + + align:start position:0% +spectral conditions and that's why we +sometimes call it spectral response of a + + align:start position:0% +sometimes call it spectral response of a + + + align:start position:0% +sometimes call it spectral response of a +solar cell device by the way those who + + align:start position:0% +solar cell device by the way those who + + + align:start position:0% +solar cell device by the way those who +need notes um if you would be so kind as + + align:start position:0% +need notes um if you would be so kind as + + + align:start position:0% +need notes um if you would be so kind as +to raise your hand Joe will uh pass them + + align:start position:0% +to raise your hand Joe will uh pass them + + + align:start position:0% +to raise your hand Joe will uh pass them +around as well so we can have uh enough + + align:start position:0% +around as well so we can have uh enough + + + align:start position:0% +around as well so we can have uh enough +for everybody to write + + align:start position:0% + + + + align:start position:0% + +down any questions as far on uh eqe + + align:start position:0% +down any questions as far on uh eqe + + + align:start position:0% +down any questions as far on uh eqe +external Quantum efficiency the + + align:start position:0% +external Quantum efficiency the + + + align:start position:0% +external Quantum efficiency the +difference between QE and the difference + + align:start position:0% +difference between QE and the difference + + + align:start position:0% +difference between QE and the difference +between uh ECE or um shall we say the + + align:start position:0% +between uh ECE or um shall we say the + + + align:start position:0% +between uh ECE or um shall we say the +energy conversion + + align:start position:0% +energy conversion + + + align:start position:0% +energy conversion +efficiency okay efficiencies they uh + + align:start position:0% +efficiency okay efficiencies they uh + + + align:start position:0% +efficiency okay efficiencies they uh +also include the subb photons right or + + align:start position:0% +also include the subb photons right or + + + align:start position:0% +also include the subb photons right or +do they just include photons which have + + align:start position:0% +do they just include photons which have + + + align:start position:0% +do they just include photons which have +the potential to make an electronal pair + + align:start position:0% +the potential to make an electronal pair + + + align:start position:0% +the potential to make an electronal pair +in principle QE um or sorry eqe should + + align:start position:0% +in principle QE um or sorry eqe should + + + align:start position:0% +in principle QE um or sorry eqe should +have eqe as a function of Lambda really + + align:start position:0% +have eqe as a function of Lambda really + + + align:start position:0% +have eqe as a function of Lambda really +and uh the photon in uh is going to be + + align:start position:0% +and uh the photon in uh is going to be + + + align:start position:0% +and uh the photon in uh is going to be +obviously uh at a certain wavelength + + align:start position:0% +obviously uh at a certain wavelength + + + align:start position:0% +obviously uh at a certain wavelength +usually uh I've rarely heard + + align:start position:0% +usually uh I've rarely heard + + + align:start position:0% +usually uh I've rarely heard +eqe uh given in a polychromatic sense + + align:start position:0% +eqe uh given in a polychromatic sense + + + align:start position:0% +eqe uh given in a polychromatic sense +where they take an entire solar spectrum + + align:start position:0% +where they take an entire solar spectrum + + + align:start position:0% +where they take an entire solar spectrum +and measure the quantum efficiency + + align:start position:0% +and measure the quantum efficiency + + + align:start position:0% +and measure the quantum efficiency +average usually Quantum efficiency is is + + align:start position:0% +average usually Quantum efficiency is is + + + align:start position:0% +average usually Quantum efficiency is is +is measured wavelength by wavelength and + + align:start position:0% +is measured wavelength by wavelength and + + + align:start position:0% +is measured wavelength by wavelength and +so you might uh change your your your + + align:start position:0% +so you might uh change your your your + + + align:start position:0% +so you might uh change your your your +monochrometer settings 20 or 30 times + + align:start position:0% +monochrometer settings 20 or 30 times + + + align:start position:0% +monochrometer settings 20 or 30 times +over or even more over a Quantum + + align:start position:0% +over or even more over a Quantum + + + align:start position:0% +over or even more over a Quantum +efficiency measurement to really map out + + align:start position:0% +efficiency measurement to really map out + + + align:start position:0% +efficiency measurement to really map out +the entire solar Spectrum from short + + align:start position:0% +the entire solar Spectrum from short + + + align:start position:0% +the entire solar Spectrum from short +wavelength in the ultraviolet all the + + align:start position:0% +wavelength in the ultraviolet all the + + + align:start position:0% +wavelength in the ultraviolet all the +way to longer wavelength in the infrared + + align:start position:0% +way to longer wavelength in the infrared + + + align:start position:0% +way to longer wavelength in the infrared +and you're absolutely right some of + + align:start position:0% +and you're absolutely right some of + + + align:start position:0% +and you're absolutely right some of +those wavelengths the photo response of + + align:start position:0% +those wavelengths the photo response of + + + align:start position:0% +those wavelengths the photo response of +the solar cell will be very close to + + align:start position:0% +the solar cell will be very close to + + + align:start position:0% +the solar cell will be very close to +zero because it just doesn't respond + + align:start position:0% +zero because it just doesn't respond + + + align:start position:0% +zero because it just doesn't respond +well at that wavelength maybe the + + align:start position:0% +well at that wavelength maybe the + + + align:start position:0% +well at that wavelength maybe the +wavelength is too short and it's being + + align:start position:0% +wavelength is too short and it's being + + + align:start position:0% +wavelength is too short and it's being +absorbed by some surface layer or maybe + + align:start position:0% +absorbed by some surface layer or maybe + + + align:start position:0% +absorbed by some surface layer or maybe +the wavelength is too long and it's just + + align:start position:0% +the wavelength is too long and it's just + + + align:start position:0% +the wavelength is too long and it's just +going straight through uh sub Bap Photon + + align:start position:0% +going straight through uh sub Bap Photon + + + align:start position:0% +going straight through uh sub Bap Photon +whereas energy conversion efficiency is + + align:start position:0% +whereas energy conversion efficiency is + + + align:start position:0% +whereas energy conversion efficiency is +really taking the entire solar spectrum + + align:start position:0% +really taking the entire solar spectrum + + + align:start position:0% +really taking the entire solar spectrum +and uh matching uh or or testing the uh + + align:start position:0% +and uh matching uh or or testing the uh + + + align:start position:0% +and uh matching uh or or testing the uh +the energy the the power coming out of + + align:start position:0% +the energy the the power coming out of + + + align:start position:0% +the energy the the power coming out of +the solar cell versus the power going in + + align:start position:0% +the solar cell versus the power going in + + + align:start position:0% +the solar cell versus the power going in +so a typical Quantum efficiency curve + + align:start position:0% +so a typical Quantum efficiency curve + + + align:start position:0% +so a typical Quantum efficiency curve +might look something like this let's + + align:start position:0% +might look something like this let's + + + align:start position:0% +might look something like this let's +walk through the axes first and then + + align:start position:0% +walk through the axes first and then + + + align:start position:0% +walk through the axes first and then +talk about the curve so the axes we have + + align:start position:0% +talk about the curve so the axes we have + + + align:start position:0% +talk about the curve so the axes we have +wavelength on the x-axis on the obsa and + + align:start position:0% +wavelength on the x-axis on the obsa and + + + align:start position:0% +wavelength on the x-axis on the obsa and +on the ordinate we have Quantum + + align:start position:0% +on the ordinate we have Quantum + + + align:start position:0% +on the ordinate we have Quantum +efficiency wavelength is varying from + + align:start position:0% +efficiency wavelength is varying from + + + align:start position:0% +efficiency wavelength is varying from +let's say the uh ultraviolet to the + + align:start position:0% +let's say the uh ultraviolet to the + + + align:start position:0% +let's say the uh ultraviolet to the +infrared and Beyond uh well beyond the + + align:start position:0% +infrared and Beyond uh well beyond the + + + align:start position:0% +infrared and Beyond uh well beyond the +red uh into the near infrared and + + align:start position:0% +red uh into the near infrared and + + + align:start position:0% +red uh into the near infrared and +probably ending somewhere around the mid + + align:start position:0% +probably ending somewhere around the mid + + + align:start position:0% +probably ending somewhere around the mid +infrared and Quantum efficiency extends + + align:start position:0% +infrared and Quantum efficiency extends + + + align:start position:0% +infrared and Quantum efficiency extends +from uh 0 to one in other words from 0% + + align:start position:0% +from uh 0 to one in other words from 0% + + + align:start position:0% +from uh 0 to one in other words from 0% +to + + align:start position:0% +to + + + align:start position:0% +to +100% And we have this box that's + + align:start position:0% +100% And we have this box that's + + + align:start position:0% +100% And we have this box that's +represented by this uh maroon line right + + align:start position:0% +represented by this uh maroon line right + + + align:start position:0% +represented by this uh maroon line right +here uh entitled ideal Quantum + + align:start position:0% +here uh entitled ideal Quantum + + + align:start position:0% +here uh entitled ideal Quantum +efficiency + + align:start position:0% +efficiency + + + align:start position:0% +efficiency +and this would be if uh at the band Gap + + align:start position:0% +and this would be if uh at the band Gap + + + align:start position:0% +and this would be if uh at the band Gap +energy all of a sudden our Quantum + + align:start position:0% +energy all of a sudden our Quantum + + + align:start position:0% +energy all of a sudden our Quantum +efficiency turned on Boop to 100% and + + align:start position:0% +efficiency turned on Boop to 100% and + + + align:start position:0% +efficiency turned on Boop to 100% and +cut across and this was the assumption + + align:start position:0% +cut across and this was the assumption + + + align:start position:0% +cut across and this was the assumption +that we made in our homework that the + + align:start position:0% +that we made in our homework that the + + + align:start position:0% +that we made in our homework that the +solar cell device would respond in this + + align:start position:0% +solar cell device would respond in this + + + align:start position:0% +solar cell device would respond in this +ideal manner in reality uh at longer + + align:start position:0% +ideal manner in reality uh at longer + + + align:start position:0% +ideal manner in reality uh at longer +wavelengths here what's going on why + + align:start position:0% +wavelengths here what's going on why + + + align:start position:0% +wavelengths here what's going on why +would there be a decrease of the quantum + + align:start position:0% +would there be a decrease of the quantum + + + align:start position:0% +would there be a decrease of the quantum +efficiency at longer + + align:start position:0% +efficiency at longer + + + align:start position:0% +efficiency at longer +wavelengths what what effect is + + align:start position:0% +wavelengths what what effect is + + + align:start position:0% +wavelengths what what effect is +happening there AB yeah the absorption + + align:start position:0% +happening there AB yeah the absorption + + + align:start position:0% +happening there AB yeah the absorption +coefficient is dropping uh and and this + + align:start position:0% +coefficient is dropping uh and and this + + + align:start position:0% +coefficient is dropping uh and and this +light is starting to go straight through + + align:start position:0% +light is starting to go straight through + + + align:start position:0% +light is starting to go straight through +the device there is a growing fraction + + align:start position:0% +the device there is a growing fraction + + + align:start position:0% +the device there is a growing fraction +of photons that are not being absorbed + + align:start position:0% +of photons that are not being absorbed + + + align:start position:0% +of photons that are not being absorbed +by the solar cell device in the very + + align:start position:0% +by the solar cell device in the very + + + align:start position:0% +by the solar cell device in the very +short wavelengths right here as I said + + align:start position:0% +short wavelengths right here as I said + + + align:start position:0% +short wavelengths right here as I said +before uh often times there's a dead + + align:start position:0% +before uh often times there's a dead + + + align:start position:0% +before uh often times there's a dead +layer right near the surface of the + + align:start position:0% +layer right near the surface of the + + + align:start position:0% +layer right near the surface of the +device that's impeding uh good uh + + align:start position:0% +device that's impeding uh good uh + + + align:start position:0% +device that's impeding uh good uh +electron whole pair charge separation + + align:start position:0% +electron whole pair charge separation + + + align:start position:0% +electron whole pair charge separation +and eventually collection and right here + + align:start position:0% +and eventually collection and right here + + + align:start position:0% +and eventually collection and right here +in the middle there's a slow but steady + + align:start position:0% +in the middle there's a slow but steady + + + align:start position:0% +in the middle there's a slow but steady +decrease of the quantum efficiency + + align:start position:0% +decrease of the quantum efficiency + + + align:start position:0% +decrease of the quantum efficiency +typically these are photons that are + + align:start position:0% +typically these are photons that are + + + align:start position:0% +typically these are photons that are +being absorbed in the absorber layer and + + align:start position:0% +being absorbed in the absorber layer and + + + align:start position:0% +being absorbed in the absorber layer and +if you think about your solar cell and + + align:start position:0% +if you think about your solar cell and + + + align:start position:0% +if you think about your solar cell and +cross-section here's your solar cell and + + align:start position:0% +cross-section here's your solar cell and + + + align:start position:0% +cross-section here's your solar cell and +cross-section these are photons being + + align:start position:0% +cross-section these are photons being + + + align:start position:0% +cross-section these are photons being +absorbed in the absorber layer + + align:start position:0% +absorbed in the absorber layer + + + align:start position:0% +absorbed in the absorber layer +generating electron whole paars which + + align:start position:0% +generating electron whole paars which + + + align:start position:0% +generating electron whole paars which +are then being separated by The Junction + + align:start position:0% +are then being separated by The Junction + + + align:start position:0% +are then being separated by The Junction +right and as we go to longer and longer + + align:start position:0% +right and as we go to longer and longer + + + align:start position:0% +right and as we go to longer and longer +wavelengths if you remember your Optical + + align:start position:0% +wavelengths if you remember your Optical + + + align:start position:0% +wavelengths if you remember your Optical +absorption coefficient begins dropping + + align:start position:0% +absorption coefficient begins dropping + + + align:start position:0% +absorption coefficient begins dropping +that means that the penetration depth of + + align:start position:0% +that means that the penetration depth of + + + align:start position:0% +that means that the penetration depth of +the light the average penetration depth + + align:start position:0% +the light the average penetration depth + + + align:start position:0% +the light the average penetration depth +of the light is increasing and so the + + align:start position:0% +of the light is increasing and so the + + + align:start position:0% +of the light is increasing and so the +average distance that the electron hold + + align:start position:0% +average distance that the electron hold + + + align:start position:0% +average distance that the electron hold +pairs are being generated from The + + align:start position:0% +pairs are being generated from The + + + align:start position:0% +pairs are being generated from The +Junction is increasing so in other words + + align:start position:0% +Junction is increasing so in other words + + + align:start position:0% +Junction is increasing so in other words +as we go from short wavelengths to + + align:start position:0% +as we go from short wavelengths to + + + align:start position:0% +as we go from short wavelengths to +longer wavelengths the distance from + + align:start position:0% +longer wavelengths the distance from + + + align:start position:0% +longer wavelengths the distance from +which the electron hole pairs are being + + align:start position:0% +which the electron hole pairs are being + + + align:start position:0% +which the electron hole pairs are being +generated from The Junction is + + align:start position:0% +generated from The Junction is + + + align:start position:0% +generated from The Junction is +increasing that means that the electron + + align:start position:0% +increasing that means that the electron + + + align:start position:0% +increasing that means that the electron +hole pairs generated at these + + align:start position:0% +hole pairs generated at these + + + align:start position:0% +hole pairs generated at these +wavelengths have further to travel to + + align:start position:0% +wavelengths have further to travel to + + + align:start position:0% +wavelengths have further to travel to +reach the junction than those electron + + align:start position:0% +reach the junction than those electron + + + align:start position:0% +reach the junction than those electron +hole pairs generated at these + + align:start position:0% +hole pairs generated at these + + + align:start position:0% +hole pairs generated at these +wavelengths closer to the front surface + + align:start position:0% +wavelengths closer to the front surface + + + align:start position:0% +wavelengths closer to the front surface +and since there's a finite probability + + align:start position:0% +and since there's a finite probability + + + align:start position:0% +and since there's a finite probability +that the electron whole pair will + + align:start position:0% +that the electron whole pair will + + + align:start position:0% +that the electron whole pair will +recombine as it travels through the + + align:start position:0% +recombine as it travels through the + + + align:start position:0% +recombine as it travels through the +material that's why you get this very + + align:start position:0% +material that's why you get this very + + + align:start position:0% +material that's why you get this very +slow uh but steady uh increase of + + align:start position:0% +slow uh but steady uh increase of + + + align:start position:0% +slow uh but steady uh increase of +quantum efficiency over the mid uh + + align:start position:0% +quantum efficiency over the mid uh + + + align:start position:0% +quantum efficiency over the mid uh +wavelength range and uh on Tuesday we'll + + align:start position:0% +wavelength range and uh on Tuesday we'll + + + align:start position:0% +wavelength range and uh on Tuesday we'll +talk more about + + align:start position:0% + + + + align:start position:0% + +that internal Quantum efficiency so for + + align:start position:0% +that internal Quantum efficiency so for + + + align:start position:0% +that internal Quantum efficiency so for +those who say well you know um there's + + align:start position:0% +those who say well you know um there's + + + align:start position:0% +those who say well you know um there's +this there's a certain Delta right here + + align:start position:0% +this there's a certain Delta right here + + + align:start position:0% +this there's a certain Delta right here +between one and my maximum uh uh + + align:start position:0% +between one and my maximum uh uh + + + align:start position:0% +between one and my maximum uh uh +response here my maximum Quantum + + align:start position:0% +response here my maximum Quantum + + + align:start position:0% +response here my maximum Quantum +efficiency and I suspect that's really + + align:start position:0% +efficiency and I suspect that's really + + + align:start position:0% +efficiency and I suspect that's really +due to the fact that a certain uh + + align:start position:0% +due to the fact that a certain uh + + + align:start position:0% +due to the fact that a certain uh +percentage of my photons are being + + align:start position:0% +percentage of my photons are being + + + align:start position:0% +percentage of my photons are being +reflected off the front surface I I know + + align:start position:0% +reflected off the front surface I I know + + + align:start position:0% +reflected off the front surface I I know +how to calculate reflectance we did that + + align:start position:0% +how to calculate reflectance we did that + + + align:start position:0% +how to calculate reflectance we did that +in uh lecture number two or three I + + align:start position:0% +in uh lecture number two or three I + + + align:start position:0% +in uh lecture number two or three I +believe uh so we know how to calculate + + align:start position:0% +believe uh so we know how to calculate + + + align:start position:0% +believe uh so we know how to calculate +reflectance off the front surface we can + + align:start position:0% +reflectance off the front surface we can + + + align:start position:0% +reflectance off the front surface we can +also measure reflectance using a spectr + + align:start position:0% +also measure reflectance using a spectr + + + align:start position:0% +also measure reflectance using a spectr +photometer and what we can do is + + align:start position:0% +photometer and what we can do is + + + align:start position:0% +photometer and what we can do is +normalize the effect of reflectance out + + align:start position:0% +normalize the effect of reflectance out + + + align:start position:0% +normalize the effect of reflectance out +by dividing our external Quantum + + align:start position:0% +by dividing our external Quantum + + + align:start position:0% +by dividing our external Quantum +efficiency by 1 minus r what in effect + + align:start position:0% +efficiency by 1 minus r what in effect + + + align:start position:0% +efficiency by 1 minus r what in effect +we're doing is we're normalizing the + + align:start position:0% +we're doing is we're normalizing the + + + align:start position:0% +we're doing is we're normalizing the +effect of reflectance out of our + + align:start position:0% +effect of reflectance out of our + + + align:start position:0% +effect of reflectance out of our +measurement so now we're only + + align:start position:0% +measurement so now we're only + + + align:start position:0% +measurement so now we're only +considering those photons that get into + + align:start position:0% +considering those photons that get into + + + align:start position:0% +considering those photons that get into +the + + align:start position:0% +the + + + align:start position:0% +the +device if you want you can think about + + align:start position:0% +device if you want you can think about + + + align:start position:0% +device if you want you can think about +the cases there if reflectance is zero + + align:start position:0% +the cases there if reflectance is zero + + + align:start position:0% +the cases there if reflectance is zero +that means your EQ is equal to your iqe + + align:start position:0% +that means your EQ is equal to your iqe + + + align:start position:0% +that means your EQ is equal to your iqe +your internal Quantum efficiency is + + align:start position:0% +your internal Quantum efficiency is + + + align:start position:0% +your internal Quantum efficiency is +equal to the external Quantum efficiency + + align:start position:0% +equal to the external Quantum efficiency + + + align:start position:0% +equal to the external Quantum efficiency +but if reflectance is say 50% if 50% of + + align:start position:0% +but if reflectance is say 50% if 50% of + + + align:start position:0% +but if reflectance is say 50% if 50% of +your photons are being reflected off the + + align:start position:0% +your photons are being reflected off the + + + align:start position:0% +your photons are being reflected off the +front surface of your device now your + + align:start position:0% +front surface of your device now your + + + align:start position:0% +front surface of your device now your +iqe is probably going to be double your + + align:start position:0% +iqe is probably going to be double your + + + align:start position:0% +iqe is probably going to be double your +external Quantum + + align:start position:0% +external Quantum + + + align:start position:0% +external Quantum +efficiency and so now uh this is an + + align:start position:0% +efficiency and so now uh this is an + + + align:start position:0% +efficiency and so now uh this is an +interesting um uh parameter because for + + align:start position:0% +interesting um uh parameter because for + + + align:start position:0% +interesting um uh parameter because for +example in our lab scale devices when + + align:start position:0% +example in our lab scale devices when + + + align:start position:0% +example in our lab scale devices when +we're testing them often times we don't + + align:start position:0% +we're testing them often times we don't + + + align:start position:0% +we're testing them often times we don't +optimize for optical properties + + align:start position:0% +optimize for optical properties + + + align:start position:0% +optimize for optical properties +sometimes we do but many times we're + + align:start position:0% +sometimes we do but many times we're + + + align:start position:0% +sometimes we do but many times we're +we're focused on the material we're + + align:start position:0% +we're focused on the material we're + + + align:start position:0% +we're focused on the material we're +focused on the junction and we don't + + align:start position:0% +focused on the junction and we don't + + + align:start position:0% +focused on the junction and we don't +bother to put the perfect anti + + align:start position:0% +bother to put the perfect anti + + + align:start position:0% +bother to put the perfect anti +reflective cating on it would take too + + align:start position:0% +reflective cating on it would take too + + + align:start position:0% +reflective cating on it would take too +long to fabricate it and so iqe gives us + + align:start position:0% +long to fabricate it and so iqe gives us + + + align:start position:0% +long to fabricate it and so iqe gives us +a good metric of how the solar cell is + + align:start position:0% +a good metric of how the solar cell is + + + align:start position:0% +a good metric of how the solar cell is +responding if we were to go through all + + align:start position:0% +responding if we were to go through all + + + align:start position:0% +responding if we were to go through all +the effort to make the light capture + + align:start position:0% +the effort to make the light capture + + + align:start position:0% +the effort to make the light capture +ideal for our + + align:start position:0% +ideal for our + + + align:start position:0% +ideal for our +device okay and that's why we sometimes + + align:start position:0% +device okay and that's why we sometimes + + + align:start position:0% +device okay and that's why we sometimes +use or report iqe in uh in studies and + + align:start position:0% +use or report iqe in uh in studies and + + + align:start position:0% +use or report iqe in uh in studies and +typical Peak values are between 80 and + + align:start position:0% +typical Peak values are between 80 and + + + align:start position:0% +typical Peak values are between 80 and +98% for moderate efficiency devices uh + + align:start position:0% +98% for moderate efficiency devices uh + + + align:start position:0% +98% for moderate efficiency devices uh +so uh it would essentially the curve + + align:start position:0% +so uh it would essentially the curve + + + align:start position:0% +so uh it would essentially the curve +would look very much like the eqe curve + + align:start position:0% +would look very much like the eqe curve + + + align:start position:0% +would look very much like the eqe curve +it just be boosted up by 1 over 1us + + align:start position:0% +it just be boosted up by 1 over 1us + + + align:start position:0% +it just be boosted up by 1 over 1us +R + + align:start position:0% +R + + + align:start position:0% +R +okay so um so so any questions so far + + align:start position:0% +okay so um so so any questions so far + + + align:start position:0% +okay so um so so any questions so far +make sure we're on the same page + + align:start position:0% +make sure we're on the same page + + + align:start position:0% +make sure we're on the same page +here + + align:start position:0% + + + + align:start position:0% + +yeah + + align:start position:0% +yeah + + + align:start position:0% +yeah +and absolutely so uh iqe is a function + + align:start position:0% +and absolutely so uh iqe is a function + + + align:start position:0% +and absolutely so uh iqe is a function +of wavelength uh our reflectivity is + + align:start position:0% +of wavelength uh our reflectivity is + + + align:start position:0% +of wavelength uh our reflectivity is +also going to be a strong function of + + align:start position:0% +also going to be a strong function of + + + align:start position:0% +also going to be a strong function of +wavelength because the real component of + + align:start position:0% +wavelength because the real component of + + + align:start position:0% +wavelength because the real component of +the refractive index is changing as a + + align:start position:0% +the refractive index is changing as a + + + align:start position:0% +the refractive index is changing as a +function of wavelength yep + + align:start position:0% +function of wavelength yep + + + align:start position:0% +function of wavelength yep +absolutely okay so this gives you a a + + align:start position:0% +absolutely okay so this gives you a a + + + align:start position:0% +absolutely okay so this gives you a a +sense sorry for the uh poor choice of + + align:start position:0% +sense sorry for the uh poor choice of + + + align:start position:0% +sense sorry for the uh poor choice of +the reflectivity colors right here this + + align:start position:0% +the reflectivity colors right here this + + + align:start position:0% +the reflectivity colors right here this +baby blue which is almost impossible to + + align:start position:0% +baby blue which is almost impossible to + + + align:start position:0% +baby blue which is almost impossible to +see but I've just traced it out with my + + align:start position:0% +see but I've just traced it out with my + + + align:start position:0% +see but I've just traced it out with my +finger that denotes the reflectivity as + + align:start position:0% +finger that denotes the reflectivity as + + + align:start position:0% +finger that denotes the reflectivity as +a function of wavelength from some data + + align:start position:0% +a function of wavelength from some data + + + align:start position:0% +a function of wavelength from some data +that I took as a graduate student so um + + align:start position:0% +that I took as a graduate student so um + + + align:start position:0% +that I took as a graduate student so um +you have some typical um uh uh Quantum + + align:start position:0% +you have some typical um uh uh Quantum + + + align:start position:0% +you have some typical um uh uh Quantum +efficiency curves right here and in the + + align:start position:0% +efficiency curves right here and in the + + + align:start position:0% +efficiency curves right here and in the +the quantum efficiency curves that are + + align:start position:0% +the quantum efficiency curves that are + + + align:start position:0% +the quantum efficiency curves that are +shown are for a pretty poor quality + + align:start position:0% +shown are for a pretty poor quality + + + align:start position:0% +shown are for a pretty poor quality +device and um in this particular case I + + align:start position:0% +device and um in this particular case I + + + align:start position:0% +device and um in this particular case I +I measured Quantum efficiency under + + align:start position:0% +I measured Quantum efficiency under + + + align:start position:0% +I measured Quantum efficiency under +short circuit conditions but with + + align:start position:0% +short circuit conditions but with + + + align:start position:0% +short circuit conditions but with +different illumination intensities so + + align:start position:0% +different illumination intensities so + + + align:start position:0% +different illumination intensities so +going from zero Sun illumination all the + + align:start position:0% +going from zero Sun illumination all the + + + align:start position:0% +going from zero Sun illumination all the +way up to one Sun illumination but this + + align:start position:0% +way up to one Sun illumination but this + + + align:start position:0% +way up to one Sun illumination but this +the device was still in short circuit + + align:start position:0% +the device was still in short circuit + + + align:start position:0% +the device was still in short circuit +conditions so what I was doing in effect + + align:start position:0% +conditions so what I was doing in effect + + + align:start position:0% +conditions so what I was doing in effect +was flooding the device with more and + + align:start position:0% +was flooding the device with more and + + + align:start position:0% +was flooding the device with more and +more and more carriers and I got this + + align:start position:0% +more and more carriers and I got this + + + align:start position:0% +more and more carriers and I got this +boost here in the middle wavelength uh + + align:start position:0% +boost here in the middle wavelength uh + + + align:start position:0% +boost here in the middle wavelength uh +range I still was limited by my surface + + align:start position:0% +range I still was limited by my surface + + + align:start position:0% +range I still was limited by my surface +I was still limited by my band Gap and + + align:start position:0% +I was still limited by my band Gap and + + + align:start position:0% +I was still limited by my band Gap and +non-absorption effects over here but in + + align:start position:0% +non-absorption effects over here but in + + + align:start position:0% +non-absorption effects over here but in +the middle I was was able to get this + + align:start position:0% +the middle I was was able to get this + + + align:start position:0% +the middle I was was able to get this +boost in performance uh simply because I + + align:start position:0% +boost in performance uh simply because I + + + align:start position:0% +boost in performance uh simply because I +was filling in uh trap States inside of + + align:start position:0% +was filling in uh trap States inside of + + + align:start position:0% +was filling in uh trap States inside of +the material this is an advanced concept + + align:start position:0% +the material this is an advanced concept + + + align:start position:0% +the material this is an advanced concept +that we're going to get to uh over the + + align:start position:0% +that we're going to get to uh over the + + + align:start position:0% +that we're going to get to uh over the +next few lectures but it gives you a + + align:start position:0% +next few lectures but it gives you a + + + align:start position:0% +next few lectures but it gives you a +sense of what a QE curve might look like + + align:start position:0% +sense of what a QE curve might look like + + + align:start position:0% +sense of what a QE curve might look like +for a device what the reflectivity might + + align:start position:0% +for a device what the reflectivity might + + + align:start position:0% +for a device what the reflectivity might +look like um and and these curves right + + align:start position:0% +look like um and and these curves right + + + align:start position:0% +look like um and and these curves right +here were iqe or internal Quantum + + align:start position:0% +here were iqe or internal Quantum + + + align:start position:0% +here were iqe or internal Quantum +efficiency okay so um you know take + + align:start position:0% +efficiency okay so um you know take + + + align:start position:0% +efficiency okay so um you know take +efficiency with a grain of Sal when you + + align:start position:0% +efficiency with a grain of Sal when you + + + align:start position:0% +efficiency with a grain of Sal when you +hear somebody reporting an efficiency + + align:start position:0% +hear somebody reporting an efficiency + + + align:start position:0% +hear somebody reporting an efficiency +value uh ask think about what efficiency + + align:start position:0% +value uh ask think about what efficiency + + + align:start position:0% +value uh ask think about what efficiency +is being measured is it uh energy + + align:start position:0% +is being measured is it uh energy + + + align:start position:0% +is being measured is it uh energy +conversion efficiency is it quantum + + align:start position:0% +conversion efficiency is it quantum + + + align:start position:0% +conversion efficiency is it quantum +efficiency internal external what + + align:start position:0% +efficiency internal external what + + + align:start position:0% +efficiency internal external what +wavelengths uh what is the nature of the + + align:start position:0% +wavelengths uh what is the nature of the + + + align:start position:0% +wavelengths uh what is the nature of the +light being used right is it is it a one + + align:start position:0% +light being used right is it is it a one + + + align:start position:0% +light being used right is it is it a one +Sun uh illumination source that has been + + align:start position:0% +Sun uh illumination source that has been + + + align:start position:0% +Sun uh illumination source that has been +well calibrated to within 2% spectral + + align:start position:0% +well calibrated to within 2% spectral + + + align:start position:0% +well calibrated to within 2% spectral +Fidelity uh spatial uniformity temporal + + align:start position:0% +Fidelity uh spatial uniformity temporal + + + align:start position:0% +Fidelity uh spatial uniformity temporal +stability is it a really bonafit good + + align:start position:0% +stability is it a really bonafit good + + + align:start position:0% +stability is it a really bonafit good +light source or is this uh some + + align:start position:0% +light source or is this uh some + + + align:start position:0% +light source or is this uh some +monochromatic light source that somebody + + align:start position:0% +monochromatic light source that somebody + + + align:start position:0% +monochromatic light source that somebody +set up because they knew aha my solar + + align:start position:0% +set up because they knew aha my solar + + + align:start position:0% +set up because they knew aha my solar +cell really responds well to say 500 + + align:start position:0% +cell really responds well to say 500 + + + align:start position:0% +cell really responds well to say 500 +nanometers light right so I'm going to + + align:start position:0% +nanometers light right so I'm going to + + + align:start position:0% +nanometers light right so I'm going to +test my I'm going to report my values + + align:start position:0% +test my I'm going to report my values + + + align:start position:0% +test my I'm going to report my values +right at that wavelength you have to + + align:start position:0% +right at that wavelength you have to + + + align:start position:0% +right at that wavelength you have to +take it with a grain of salt um and uh + + align:start position:0% +take it with a grain of salt um and uh + + + align:start position:0% +take it with a grain of salt um and uh +yeah exactly what is the intensity of + + align:start position:0% +yeah exactly what is the intensity of + + + align:start position:0% +yeah exactly what is the intensity of +the light that's being used as well + + align:start position:0% +the light that's being used as well + + + align:start position:0% +the light that's being used as well +that's very important as we just saw + + align:start position:0% +that's very important as we just saw + + + align:start position:0% +that's very important as we just saw +right over here because the bulk + + align:start position:0% +right over here because the bulk + + + align:start position:0% +right over here because the bulk +material uh is going to respond + + align:start position:0% +material uh is going to respond + + + align:start position:0% +material uh is going to respond +differently there are certain trap + + align:start position:0% +differently there are certain trap + + + align:start position:0% +differently there are certain trap +States for electrons inside of the + + align:start position:0% +States for electrons inside of the + + + align:start position:0% +States for electrons inside of the +material and as you add more and more + + align:start position:0% +material and as you add more and more + + + align:start position:0% +material and as you add more and more +light you're flooding those traps they + + align:start position:0% +light you're flooding those traps they + + + align:start position:0% +light you're flooding those traps they +become filled and the electrons can move + + align:start position:0% +become filled and the electrons can move + + + align:start position:0% +become filled and the electrons can move +through the material more easily right + + align:start position:0% +through the material more easily right + + + align:start position:0% +through the material more easily right +that's why you get this boost of + + align:start position:0% +that's why you get this boost of + + + align:start position:0% +that's why you get this boost of +response as you increase the + + align:start position:0% +response as you increase the + + + align:start position:0% +response as you increase the +illumination intensity in this + + align:start position:0% +illumination intensity in this + + + align:start position:0% +illumination intensity in this +particular + + align:start position:0% +particular + + + align:start position:0% +particular +experiment so these are all questions + + align:start position:0% +experiment so these are all questions + + + align:start position:0% +experiment so these are all questions +that you should ask yourselves when you + + align:start position:0% +that you should ask yourselves when you + + + align:start position:0% +that you should ask yourselves when you +see Quantum efficiency uh internal + + align:start position:0% +see Quantum efficiency uh internal + + + align:start position:0% +see Quantum efficiency uh internal +Quantum uh external Quantum efficiency + + align:start position:0% +Quantum uh external Quantum efficiency + + + align:start position:0% +Quantum uh external Quantum efficiency +values reported and or energy conversion + + align:start position:0% +values reported and or energy conversion + + + align:start position:0% +values reported and or energy conversion +efficiencies is what is what is really + + align:start position:0% +efficiencies is what is what is really + + + align:start position:0% +efficiencies is what is what is really +happening what are they majoring this + + align:start position:0% +happening what are they majoring this + + + align:start position:0% +happening what are they majoring this +right here a paper out of Paul lotus' + + align:start position:0% +right here a paper out of Paul lotus' + + + align:start position:0% +right here a paper out of Paul lotus' +lab from 2002 was in my humble opinion + + align:start position:0% +lab from 2002 was in my humble opinion + + + align:start position:0% +lab from 2002 was in my humble opinion +an excellent example of honest + + align:start position:0% +an excellent example of honest + + + align:start position:0% +an excellent example of honest +efficiency reporting um first off they + + align:start position:0% +efficiency reporting um first off they + + + align:start position:0% +efficiency reporting um first off they +uh you know they they picked their + + align:start position:0% +uh you know they they picked their + + + align:start position:0% +uh you know they they picked their +highest values and and put their best + + align:start position:0% +highest values and and put their best + + + align:start position:0% +highest values and and put their best +foot forward and said look we have a + + align:start position:0% +foot forward and said look we have a + + + align:start position:0% +foot forward and said look we have a +Quantum efficiency over 54% uh and a + + align:start position:0% +Quantum efficiency over 54% uh and a + + + align:start position:0% +Quantum efficiency over 54% uh and a +monochromatic power conversion + + align:start position:0% +monochromatic power conversion + + + align:start position:0% +monochromatic power conversion +efficiency of 6.9% under very low + + align:start position:0% +efficiency of 6.9% under very low + + + align:start position:0% +efficiency of 6.9% under very low +intensity light um uh at 55 nmet right + + align:start position:0% +intensity light um uh at 55 nmet right + + + align:start position:0% +intensity light um uh at 55 nmet right +so first off they put their best foot + + align:start position:0% +so first off they put their best foot + + + align:start position:0% +so first off they put their best foot +forward and said under optimal + + align:start position:0% +forward and said under optimal + + + align:start position:0% +forward and said under optimal +conditions monochromatic light that's + + align:start position:0% +conditions monochromatic light that's + + + align:start position:0% +conditions monochromatic light that's +what we get but also under air mass 1.5 + + align:start position:0% +what we get but also under air mass 1.5 + + + align:start position:0% +what we get but also under air mass 1.5 +Global solar conditions under the + + align:start position:0% +Global solar conditions under the + + + align:start position:0% +Global solar conditions under the +standard solar Spectrum we obtained an + + align:start position:0% +standard solar Spectrum we obtained an + + + align:start position:0% +standard solar Spectrum we obtained an +energy conversion effic or a power + + align:start position:0% +energy conversion effic or a power + + + align:start position:0% +energy conversion effic or a power +conversion efficiency of + + align:start position:0% +conversion efficiency of + + + align:start position:0% +conversion efficiency of +1.7% so both values are put there out on + + align:start position:0% +1.7% so both values are put there out on + + + align:start position:0% +1.7% so both values are put there out on +the table and they say look here's + + align:start position:0% +the table and they say look here's + + + align:start position:0% +the table and they say look here's +here's a characterization of our device + + align:start position:0% +here's a characterization of our device + + + align:start position:0% +here's a characterization of our device +so I I really like this pay-per-view it + + align:start position:0% +so I I really like this pay-per-view it + + + align:start position:0% +so I I really like this pay-per-view it +was back in 2002 right at the beginning + + align:start position:0% +was back in 2002 right at the beginning + + + align:start position:0% +was back in 2002 right at the beginning +of the the new wave of of of new + + align:start position:0% +of the the new wave of of of new + + + align:start position:0% +of the the new wave of of of new +materials in PV uh so to speak this this + + align:start position:0% +materials in PV uh so to speak this this + + + align:start position:0% +materials in PV uh so to speak this this +third wave of PV uh in in the United + + align:start position:0% +third wave of PV uh in in the United + + + align:start position:0% +third wave of PV uh in in the United +States and it was a beautiful example of + + align:start position:0% +States and it was a beautiful example of + + + align:start position:0% +States and it was a beautiful example of +a really well reported uh carefully + + align:start position:0% +a really well reported uh carefully + + + align:start position:0% +a really well reported uh carefully +described uh + + align:start position:0% +described uh + + + align:start position:0% +described uh +efficiency any further uh thoughts or + + align:start position:0% +efficiency any further uh thoughts or + + + align:start position:0% +efficiency any further uh thoughts or +comments before we jump on to the next + + align:start position:0% +comments before we jump on to the next + + + align:start position:0% +comments before we jump on to the next +uh topics of the day how do you have a + + align:start position:0% +uh topics of the day how do you have a + + + align:start position:0% +uh topics of the day how do you have a +QE curve for zero Suns I noticed on your + + align:start position:0% +QE curve for zero Suns I noticed on your + + + align:start position:0% +QE curve for zero Suns I noticed on your +PL or is that kind of an extrap yeah so + + align:start position:0% +PL or is that kind of an extrap yeah so + + + align:start position:0% +PL or is that kind of an extrap yeah so +these are this is the bias condition uh + + align:start position:0% +these are this is the bias condition uh + + + align:start position:0% +these are this is the bias condition uh +sorry the bias lighting condition not + + align:start position:0% +sorry the bias lighting condition not + + + align:start position:0% +sorry the bias lighting condition not +the bias voltage as in uh battery but + + align:start position:0% +the bias voltage as in uh battery but + + + align:start position:0% +the bias voltage as in uh battery but +bias lighting is in I I shine a a a + + align:start position:0% +bias lighting is in I I shine a a a + + + align:start position:0% +bias lighting is in I I shine a a a +light source a polychromatic light + + align:start position:0% +light source a polychromatic light + + + align:start position:0% +light source a polychromatic light +source at at my material I believe in + + align:start position:0% +source at at my material I believe in + + + align:start position:0% +source at at my material I believe in +that case it was a hen lamp with a + + align:start position:0% +that case it was a hen lamp with a + + + align:start position:0% +that case it was a hen lamp with a +series of filters to simulate the the + + align:start position:0% +series of filters to simulate the the + + + align:start position:0% +series of filters to simulate the the +solar spectrum and um obviously you you + + align:start position:0% +solar spectrum and um obviously you you + + + align:start position:0% +solar spectrum and um obviously you you +you can't measure a Quantum efficiency + + align:start position:0% +you can't measure a Quantum efficiency + + + align:start position:0% +you can't measure a Quantum efficiency +without having some light involved um + + align:start position:0% +without having some light involved um + + + align:start position:0% +without having some light involved um +and so the light that was being + + align:start position:0% +and so the light that was being + + + align:start position:0% +and so the light that was being +generated by the monochrometer was much + + align:start position:0% +generated by the monochrometer was much + + + align:start position:0% +generated by the monochrometer was much +lower in intensity than uh these uh + + align:start position:0% +lower in intensity than uh these uh + + + align:start position:0% +lower in intensity than uh these uh +illumination intensities here and so it + + align:start position:0% +illumination intensities here and so it + + + align:start position:0% +illumination intensities here and so it +was more of a pertubation on top of a + + align:start position:0% +was more of a pertubation on top of a + + + align:start position:0% +was more of a pertubation on top of a +steadystate background and we ran the + + align:start position:0% +steadystate background and we ran the + + + align:start position:0% +steadystate background and we ran the +measurement in exactly those conditions + + align:start position:0% +measurement in exactly those conditions + + + align:start position:0% +measurement in exactly those conditions +we had a steady state background light + + align:start position:0% +we had a steady state background light + + + align:start position:0% +we had a steady state background light +and then we chopped uh the monochrometer + + align:start position:0% +and then we chopped uh the monochrometer + + + align:start position:0% +and then we chopped uh the monochrometer +light coming in uh and used the lock and + + align:start position:0% +light coming in uh and used the lock and + + + align:start position:0% +light coming in uh and used the lock and +amplifier to track that particular + + align:start position:0% +amplifier to track that particular + + + align:start position:0% +amplifier to track that particular +frequency so we're able to detect the + + align:start position:0% +frequency so we're able to detect the + + + align:start position:0% +frequency so we're able to detect the +small perturbation due to the + + align:start position:0% +small perturbation due to the + + + align:start position:0% +small perturbation due to the +monochromatic light coming in on top of + + align:start position:0% +monochromatic light coming in on top of + + + align:start position:0% +monochromatic light coming in on top of +the study + + align:start position:0% +the study + + + align:start position:0% +the study +background yeah there's no International + + align:start position:0% +background yeah there's no International + + + align:start position:0% +background yeah there's no International +standard to report efficiency or + + align:start position:0% +standard to report efficiency or + + + align:start position:0% +standard to report efficiency or +convention uh there are uh there are + + align:start position:0% +convention uh there are uh there are + + + align:start position:0% +convention uh there are uh there are +conventions International conventions to + + align:start position:0% +conventions International conventions to + + + align:start position:0% +conventions International conventions to +report uh energy conversion efficiencies + + align:start position:0% +report uh energy conversion efficiencies + + + align:start position:0% +report uh energy conversion efficiencies +and I believe there might also be for uh + + align:start position:0% +and I believe there might also be for uh + + + align:start position:0% +and I believe there might also be for uh +Quantum efficiencies as well let me look + + align:start position:0% +Quantum efficiencies as well let me look + + + align:start position:0% +Quantum efficiencies as well let me look +into that um why don't we take note of + + align:start position:0% +into that um why don't we take note of + + + align:start position:0% +into that um why don't we take note of +that and bring back the precise ASM + + align:start position:0% +that and bring back the precise ASM + + + align:start position:0% +that and bring back the precise ASM +standards next time uh and I believe + + align:start position:0% +standards next time uh and I believe + + + align:start position:0% +standards next time uh and I believe +also there are uh other entities like + + align:start position:0% +also there are uh other entities like + + + align:start position:0% +also there are uh other entities like +IEC uh that have their own systems for + + align:start position:0% +IEC uh that have their own systems for + + + align:start position:0% +IEC uh that have their own systems for +it um there are about four four + + align:start position:0% +it um there are about four four + + + align:start position:0% +it um there are about four four +Laboratories worldwide that + + align:start position:0% +Laboratories worldwide that + + + align:start position:0% +Laboratories worldwide that +are authorized to give uh standard + + align:start position:0% +are authorized to give uh standard + + + align:start position:0% +are authorized to give uh standard +efficiency measurements so they have + + align:start position:0% +efficiency measurements so they have + + + align:start position:0% +efficiency measurements so they have +very carefully calibrated uh um Quantum + + align:start position:0% +very carefully calibrated uh um Quantum + + + align:start position:0% +very carefully calibrated uh um Quantum +efficiency measurement devices very + + align:start position:0% +efficiency measurement devices very + + + align:start position:0% +efficiency measurement devices very +carefully calibrated solar simulators + + align:start position:0% +carefully calibrated solar simulators + + + align:start position:0% +carefully calibrated solar simulators +and um if you really think you have a + + align:start position:0% +and um if you really think you have a + + + align:start position:0% +and um if you really think you have a +record efficiency cell you should get it + + align:start position:0% +record efficiency cell you should get it + + + align:start position:0% +record efficiency cell you should get it +checked at one of those Laboratories you + + align:start position:0% +checked at one of those Laboratories you + + + align:start position:0% +checked at one of those Laboratories you +shouldn't just uh report what you have + + align:start position:0% +shouldn't just uh report what you have + + + align:start position:0% +shouldn't just uh report what you have +coming off of your lab-based system or + + align:start position:0% +coming off of your lab-based system or + + + align:start position:0% +coming off of your lab-based system or +you may even want to go around to a few + + align:start position:0% +you may even want to go around to a few + + + align:start position:0% +you may even want to go around to a few +different Labs here at MIT first yeah + + align:start position:0% +different Labs here at MIT first yeah + + + align:start position:0% +different Labs here at MIT first yeah +one might have a better better + + align:start position:0% +one might have a better better + + + align:start position:0% +one might have a better better +calibrated solar simulator than another + + align:start position:0% +calibrated solar simulator than another + + + align:start position:0% +calibrated solar simulator than another +what we're going to do now is dive into + + align:start position:0% +what we're going to do now is dive into + + + align:start position:0% +what we're going to do now is dive into +uh some of the common factors that cause + + align:start position:0% +uh some of the common factors that cause + + + align:start position:0% +uh some of the common factors that cause +solar cell IV curves to deviate from + + align:start position:0% +solar cell IV curves to deviate from + + + align:start position:0% +solar cell IV curves to deviate from +normal ideal diode model we're going to + + align:start position:0% +normal ideal diode model we're going to + + + align:start position:0% +normal ideal diode model we're going to +talk about shun and series resistance uh + + align:start position:0% +talk about shun and series resistance uh + + + align:start position:0% +talk about shun and series resistance uh +recombination currents um maybe we'll + + align:start position:0% +recombination currents um maybe we'll + + + align:start position:0% +recombination currents um maybe we'll +get to current crowding some other + + align:start position:0% +get to current crowding some other + + + align:start position:0% +get to current crowding some other +effects uh basically what we're doing + + align:start position:0% +effects uh basically what we're doing + + + align:start position:0% +effects uh basically what we're doing +now in number two is we're beginning to + + align:start position:0% +now in number two is we're beginning to + + + align:start position:0% +now in number two is we're beginning to +say okay now that we understand an ideal + + align:start position:0% +say okay now that we understand an ideal + + + align:start position:0% +say okay now that we understand an ideal +di now that we have an ideal picture of + + align:start position:0% +di now that we have an ideal picture of + + + align:start position:0% +di now that we have an ideal picture of +how our solar cell works let's bring it + + align:start position:0% +how our solar cell works let's bring it + + + align:start position:0% +how our solar cell works let's bring it +down to real life and talk about all the + + align:start position:0% +down to real life and talk about all the + + + align:start position:0% +down to real life and talk about all the +things that can go wrong because when + + align:start position:0% +things that can go wrong because when + + + align:start position:0% +things that can go wrong because when +you try to make a solar cell in the lab + + align:start position:0% +you try to make a solar cell in the lab + + + align:start position:0% +you try to make a solar cell in the lab +these are the things that are going to + + align:start position:0% +these are the things that are going to + + + align:start position:0% +these are the things that are going to +start um nipping at your heels so to + + align:start position:0% +start um nipping at your heels so to + + + align:start position:0% +start um nipping at your heels so to +speak so we'll start out with an + + align:start position:0% +speak so we'll start out with an + + + align:start position:0% +speak so we'll start out with an +equivalent circuit diagram of a solar + + align:start position:0% +equivalent circuit diagram of a solar + + + align:start position:0% +equivalent circuit diagram of a solar +cell device and this might be new to + + align:start position:0% +cell device and this might be new to + + + align:start position:0% +cell device and this might be new to +some folks um but it's it's all stuff + + align:start position:0% +some folks um but it's it's all stuff + + + align:start position:0% +some folks um but it's it's all stuff +you've seen so far what we have over + + align:start position:0% +you've seen so far what we have over + + + align:start position:0% +you've seen so far what we have over +here is the current generation source of + + align:start position:0% +here is the current generation source of + + + align:start position:0% +here is the current generation source of +the it's the solar cell operating under + + align:start position:0% +the it's the solar cell operating under + + + align:start position:0% +the it's the solar cell operating under +forward bias conditions under + + align:start position:0% +forward bias conditions under + + + align:start position:0% +forward bias conditions under +illumination generating a voltage in a + + align:start position:0% +illumination generating a voltage in a + + + align:start position:0% +illumination generating a voltage in a +current we have a diode here that + + align:start position:0% +current we have a diode here that + + + align:start position:0% +current we have a diode here that +prevents the backflow of current and + + align:start position:0% +prevents the backflow of current and + + + align:start position:0% +prevents the backflow of current and +forces the current to go out through the + + align:start position:0% +forces the current to go out through the + + + align:start position:0% +forces the current to go out through the +external circuit Loop right and it + + align:start position:0% +external circuit Loop right and it + + + align:start position:0% +external circuit Loop right and it +forces it to drive the external load + + align:start position:0% +forces it to drive the external load + + + align:start position:0% +forces it to drive the external load +which would be attached to that little + + align:start position:0% +which would be attached to that little + + + align:start position:0% +which would be attached to that little +circle over there and that other little + + align:start position:0% +circle over there and that other little + + + align:start position:0% +circle over there and that other little +circle over there so you can imagine an + + align:start position:0% +circle over there so you can imagine an + + + align:start position:0% +circle over there so you can imagine an +external circuit attaching itself right + + align:start position:0% +external circuit attaching itself right + + + align:start position:0% +external circuit attaching itself right +there so uh the diode if the diode + + align:start position:0% +there so uh the diode if the diode + + + align:start position:0% +there so uh the diode if the diode +quality is high if it's good it will + + align:start position:0% +quality is high if it's good it will + + + align:start position:0% +quality is high if it's good it will +prevent the backflow of current if the + + align:start position:0% +prevent the backflow of current if the + + + align:start position:0% +prevent the backflow of current if the +diode quality is poor uh you will have + + align:start position:0% +diode quality is poor uh you will have + + + align:start position:0% +diode quality is poor uh you will have +so-called leakage current current + + align:start position:0% +so-called leakage current current + + + align:start position:0% +so-called leakage current current +leaking into the diode uh back if you + + align:start position:0% +leaking into the diode uh back if you + + + align:start position:0% +leaking into the diode uh back if you +want to think about it in forward bias + + align:start position:0% +want to think about it in forward bias + + + align:start position:0% +want to think about it in forward bias +conditions here's your solar cell + + align:start position:0% +conditions here's your solar cell + + + align:start position:0% +conditions here's your solar cell +forward bias you have light electrons + + align:start position:0% +forward bias you have light electrons + + + align:start position:0% +forward bias you have light electrons +coming in separated by the electron by + + align:start position:0% +coming in separated by the electron by + + + align:start position:0% +coming in separated by the electron by +the electric field instead of powering + + align:start position:0% +the electric field instead of powering + + + align:start position:0% +the electric field instead of powering +the external load and coming back into + + align:start position:0% +the external load and coming back into + + + align:start position:0% +the external load and coming back into +the device through the back leakage + + align:start position:0% +the device through the back leakage + + + align:start position:0% +the device through the back leakage +current would be the electrons going + + align:start position:0% +current would be the electrons going + + + align:start position:0% +current would be the electrons going +back up the barrier right going back + + align:start position:0% +back up the barrier right going back + + + align:start position:0% +back up the barrier right going back +into the base of the device uh the + + align:start position:0% +into the base of the device uh the + + + align:start position:0% +into the base of the device uh the +so-called diffusion current so this is + + align:start position:0% +so-called diffusion current so this is + + + align:start position:0% +so-called diffusion current so this is +that diode right here representing the + + align:start position:0% +that diode right here representing the + + + align:start position:0% +that diode right here representing the +diffusion current or the uh the in that + + align:start position:0% +diffusion current or the uh the in that + + + align:start position:0% +diffusion current or the uh the in that +particular case inal uh the equivalent + + align:start position:0% +particular case inal uh the equivalent + + + align:start position:0% +particular case inal uh the equivalent +circuit diagram this is representing the + + align:start position:0% +circuit diagram this is representing the + + + align:start position:0% +circuit diagram this is representing the +resistance to diffusion if you will so + + align:start position:0% +resistance to diffusion if you will so + + + align:start position:0% +resistance to diffusion if you will so +we have this uh voltage and and current + + align:start position:0% +we have this uh voltage and and current + + + align:start position:0% +we have this uh voltage and and current +being generated by the solar cell and + + align:start position:0% +being generated by the solar cell and + + + align:start position:0% +being generated by the solar cell and +that would be described by the ideal + + align:start position:0% +that would be described by the ideal + + + align:start position:0% +that would be described by the ideal +diode equation my apologies there should + + align:start position:0% +diode equation my apologies there should + + + align:start position:0% +diode equation my apologies there should +be actually X of this minus one right + + align:start position:0% +be actually X of this minus one right + + + align:start position:0% +be actually X of this minus one right +there we should take note of that and + + align:start position:0% +there we should take note of that and + + + align:start position:0% +there we should take note of that and +corrected I just happen to notice that + + align:start position:0% +corrected I just happen to notice that + + + align:start position:0% +corrected I just happen to notice that +um okay so the ideal diode equation is + + align:start position:0% +um okay so the ideal diode equation is + + + align:start position:0% +um okay so the ideal diode equation is +right here and uh this is the current + + align:start position:0% +right here and uh this is the current + + + align:start position:0% +right here and uh this is the current +density versus voltage so we have uh in + + align:start position:0% +density versus voltage so we have uh in + + + align:start position:0% +density versus voltage so we have uh in +uh uh linear log scale or or or or axis + + align:start position:0% +uh uh linear log scale or or or or axis + + + align:start position:0% +uh uh linear log scale or or or or axis +we have a straight line uh that would on + + align:start position:0% +we have a straight line uh that would on + + + align:start position:0% +we have a straight line uh that would on +a linear linear scale we would have an + + align:start position:0% +a linear linear scale we would have an + + + align:start position:0% +a linear linear scale we would have an +exponential curve right so an + + align:start position:0% +exponential curve right so an + + + align:start position:0% +exponential curve right so an +exponential function exponential curve + + align:start position:0% +exponential function exponential curve + + + align:start position:0% +exponential function exponential curve +up here and a straight line in linear + + align:start position:0% +up here and a straight line in linear + + + align:start position:0% +up here and a straight line in linear +log uh scale I'm trying to sensitize you + + align:start position:0% +log uh scale I'm trying to sensitize you + + + align:start position:0% +log uh scale I'm trying to sensitize you +to the two ways of looking at this both + + align:start position:0% +to the two ways of looking at this both + + + align:start position:0% +to the two ways of looking at this both +uh a linear scale and a log scale of + + align:start position:0% +uh a linear scale and a log scale of + + + align:start position:0% +uh a linear scale and a log scale of +current in the y- AIS because both will + + align:start position:0% +current in the y- AIS because both will + + + align:start position:0% +current in the y- AIS because both will +tell us something from the linear scale + + align:start position:0% +tell us something from the linear scale + + + align:start position:0% +tell us something from the linear scale +up here on the upper right it will be + + align:start position:0% +up here on the upper right it will be + + + align:start position:0% +up here on the upper right it will be +very easy for us to see the fill Factor + + align:start position:0% +very easy for us to see the fill Factor + + + align:start position:0% +very easy for us to see the fill Factor +we can just glance at that curve and see + + align:start position:0% +we can just glance at that curve and see + + + align:start position:0% +we can just glance at that curve and see +oh it looks really box-like it must have + + align:start position:0% +oh it looks really box-like it must have + + + align:start position:0% +oh it looks really box-like it must have +a large fill factor from this curve down + + align:start position:0% +a large fill factor from this curve down + + + align:start position:0% +a large fill factor from this curve down +here we can begin to see deviations from + + align:start position:0% +here we can begin to see deviations from + + + align:start position:0% +here we can begin to see deviations from +ideality if anything causes this curve + + align:start position:0% +ideality if anything causes this curve + + + align:start position:0% +ideality if anything causes this curve +to bend up or down either down here or + + align:start position:0% +to bend up or down either down here or + + + align:start position:0% +to bend up or down either down here or +up here we're going to see it really + + align:start position:0% +up here we're going to see it really + + + align:start position:0% +up here we're going to see it really +quick on the linear on the log scale and + + align:start position:0% +quick on the linear on the log scale and + + + align:start position:0% +quick on the linear on the log scale and +that's why looking at the IV curve in + + align:start position:0% +that's why looking at the IV curve in + + + align:start position:0% +that's why looking at the IV curve in +both ways is helpful it's uh a method of + + align:start position:0% +both ways is helpful it's uh a method of + + + align:start position:0% +both ways is helpful it's uh a method of +diagnosing the problem + + align:start position:0% +diagnosing the problem + + + align:start position:0% +diagnosing the problem +quickly so what we're going to do now is + + align:start position:0% +quickly so what we're going to do now is + + + align:start position:0% +quickly so what we're going to do now is +to take our equivalent circuit and begin + + align:start position:0% +to take our equivalent circuit and begin + + + align:start position:0% +to take our equivalent circuit and begin +adding a few things to it that represent + + align:start position:0% +adding a few things to it that represent + + + align:start position:0% +adding a few things to it that represent +realistic uh effects that we might see + + align:start position:0% +realistic uh effects that we might see + + + align:start position:0% +realistic uh effects that we might see +in in a real device so the first thing + + align:start position:0% +in in a real device so the first thing + + + align:start position:0% +in in a real device so the first thing +that we might do is say well listen a + + align:start position:0% +that we might do is say well listen a + + + align:start position:0% +that we might do is say well listen a +real device has a finite series + + align:start position:0% +real device has a finite series + + + align:start position:0% +real device has a finite series +resistance and that can come from a + + align:start position:0% +resistance and that can come from a + + + align:start position:0% +resistance and that can come from a +variety of sources we'll talk about + + align:start position:0% +variety of sources we'll talk about + + + align:start position:0% +variety of sources we'll talk about +those in a few minutes but we might add + + align:start position:0% +those in a few minutes but we might add + + + align:start position:0% +those in a few minutes but we might add +a series resistance component right up + + align:start position:0% +a series resistance component right up + + + align:start position:0% +a series resistance component right up +there so let's look back I'm going to + + align:start position:0% +there so let's look back I'm going to + + + align:start position:0% +there so let's look back I'm going to +flip back and forth between the two + + align:start position:0% +flip back and forth between the two + + + align:start position:0% +flip back and forth between the two +slides just so folks can really see what + + align:start position:0% +slides just so folks can really see what + + + align:start position:0% +slides just so folks can really see what +the difference is this was the ideal + + align:start position:0% +the difference is this was the ideal + + + align:start position:0% +the difference is this was the ideal +case that's the with series resistance + + align:start position:0% +case that's the with series resistance + + + align:start position:0% +case that's the with series resistance +again ideal with series resistance up + + align:start position:0% +again ideal with series resistance up + + + align:start position:0% +again ideal with series resistance up +there in the equivalent circuit great so + + align:start position:0% +there in the equivalent circuit great so + + + align:start position:0% +there in the equivalent circuit great so +what have we done well we've added a + + align:start position:0% +what have we done well we've added a + + + align:start position:0% +what have we done well we've added a +series resistance component which is + + align:start position:0% +series resistance component which is + + + align:start position:0% +series resistance component which is +essentially dropping the voltage output + + align:start position:0% +essentially dropping the voltage output + + + align:start position:0% +essentially dropping the voltage output +of our solar cell and notice what else + + align:start position:0% +of our solar cell and notice what else + + + align:start position:0% +of our solar cell and notice what else +happened now we have a nonlinear + + align:start position:0% +happened now we have a nonlinear + + + align:start position:0% +happened now we have a nonlinear +equation our current density is a + + align:start position:0% +equation our current density is a + + + align:start position:0% +equation our current density is a +function of our current + + align:start position:0% +function of our current + + + align:start position:0% +function of our current +density right so this is becoming more + + align:start position:0% +density right so this is becoming more + + + align:start position:0% +density right so this is becoming more +difficult to uh uh uh to solve um + + align:start position:0% +difficult to uh uh uh to solve um + + + align:start position:0% +difficult to uh uh uh to solve um +analytically uh and what is happening to + + align:start position:0% +analytically uh and what is happening to + + + align:start position:0% +analytically uh and what is happening to +RV characteristics well let's uh look uh + + align:start position:0% +RV characteristics well let's uh look uh + + + align:start position:0% +RV characteristics well let's uh look uh +we'll go back once again to our ideal + + align:start position:0% +we'll go back once again to our ideal + + + align:start position:0% +we'll go back once again to our ideal +diod equation right here we have a very + + align:start position:0% +diod equation right here we have a very + + + align:start position:0% +diod equation right here we have a very +sharp box- like IV curve under the ideal + + align:start position:0% +sharp box- like IV curve under the ideal + + + align:start position:0% +sharp box- like IV curve under the ideal +conditions now when we introduced the + + align:start position:0% +conditions now when we introduced the + + + align:start position:0% +conditions now when we introduced the +series resistance component we begun + + align:start position:0% +series resistance component we begun + + + align:start position:0% +series resistance component we begun +smoothing out that IV curve the fill + + align:start position:0% +smoothing out that IV curve the fill + + + align:start position:0% +smoothing out that IV curve the fill +Factor has dropped take a look ideal + + align:start position:0% +Factor has dropped take a look ideal + + + align:start position:0% +Factor has dropped take a look ideal +conditions sharp very large fill Factor + + align:start position:0% +conditions sharp very large fill Factor + + + align:start position:0% +conditions sharp very large fill Factor +now we've added the series resistance + + align:start position:0% +now we've added the series resistance + + + align:start position:0% +now we've added the series resistance +component The Fill Factor has begun + + align:start position:0% +component The Fill Factor has begun + + + align:start position:0% +component The Fill Factor has begun +dropping if we look at it in log scale + + align:start position:0% +dropping if we look at it in log scale + + + align:start position:0% +dropping if we look at it in log scale +it's very easy to detect that series + + align:start position:0% +it's very easy to detect that series + + + align:start position:0% +it's very easy to detect that series +resistance we can see it right here this + + align:start position:0% +resistance we can see it right here this + + + align:start position:0% +resistance we can see it right here this +used to be our curve right so again this + + align:start position:0% +used to be our curve right so again this + + + align:start position:0% +used to be our curve right so again this +was the ideal case straight line again + + align:start position:0% +was the ideal case straight line again + + + align:start position:0% +was the ideal case straight line again +again this is log of current versus + + align:start position:0% +again this is log of current versus + + + align:start position:0% +again this is log of current versus +linear voltage so the x- axis of the two + + align:start position:0% +linear voltage so the x- axis of the two + + + align:start position:0% +linear voltage so the x- axis of the two +plots here are the same I'm only + + align:start position:0% +plots here are the same I'm only + + + align:start position:0% +plots here are the same I'm only +changing the y- axis from linear scale + + align:start position:0% +changing the y- axis from linear scale + + + align:start position:0% +changing the y- axis from linear scale +up there to log scale down here and + + align:start position:0% +up there to log scale down here and + + + align:start position:0% +up there to log scale down here and +notice what happens if I add the series + + align:start position:0% +notice what happens if I add the series + + + align:start position:0% +notice what happens if I add the series +resistance component now I begin + + align:start position:0% +resistance component now I begin + + + align:start position:0% +resistance component now I begin +dropping + + align:start position:0% +dropping + + + align:start position:0% +dropping +off so this is a Telltale sign when you + + align:start position:0% +off so this is a Telltale sign when you + + + align:start position:0% +off so this is a Telltale sign when you +take an IV curve and you see that that + + align:start position:0% +take an IV curve and you see that that + + + align:start position:0% +take an IV curve and you see that that +you know you have some series resistance + + align:start position:0% +you know you have some series resistance + + + align:start position:0% +you know you have some series resistance +effect inside of your external circuit + + align:start position:0% +effect inside of your external circuit + + + align:start position:0% +effect inside of your external circuit +or your solar cell from combination of + + align:start position:0% +or your solar cell from combination of + + + align:start position:0% +or your solar cell from combination of +of the two yes Ashley so the this curve + + align:start position:0% +of the two yes Ashley so the this curve + + + align:start position:0% +of the two yes Ashley so the this curve +it looks like the Ser resistance really + + align:start position:0% +it looks like the Ser resistance really + + + align:start position:0% +it looks like the Ser resistance really +only starts to have an effect once you + + align:start position:0% +only starts to have an effect once you + + + align:start position:0% +only starts to have an effect once you +have a higher voltage absolutely and + + align:start position:0% +have a higher voltage absolutely and + + + align:start position:0% +have a higher voltage absolutely and +that you can begin to see directly from + + align:start position:0% +that you can begin to see directly from + + + align:start position:0% +that you can begin to see directly from +the equation right here as well uh take + + align:start position:0% +the equation right here as well uh take + + + align:start position:0% +the equation right here as well uh take +the limit of of low voltage and the + + align:start position:0% +the limit of of low voltage and the + + + align:start position:0% +the limit of of low voltage and the +limit of high voltage or another way to + + align:start position:0% +limit of high voltage or another way to + + + align:start position:0% +limit of high voltage or another way to +put it would be the high current really + + align:start position:0% +put it would be the high current really + + + align:start position:0% +put it would be the high current really +um and and that uh the high current to + + align:start position:0% +um and and that uh the high current to + + + align:start position:0% +um and and that uh the high current to +voltage ratio only begins to take on up + + align:start position:0% +voltage ratio only begins to take on up + + + align:start position:0% +voltage ratio only begins to take on up +at higher voltages because of the + + align:start position:0% +at higher voltages because of the + + + align:start position:0% +at higher voltages because of the +exponential function of that + + align:start position:0% +exponential function of that + + + align:start position:0% +exponential function of that +curve so that's a very very important + + align:start position:0% +curve so that's a very very important + + + align:start position:0% +curve so that's a very very important +and astute observation that the series + + align:start position:0% +and astute observation that the series + + + align:start position:0% +and astute observation that the series +resistance begins to kill you at High + + align:start position:0% +resistance begins to kill you at High + + + align:start position:0% +resistance begins to kill you at High +forward bias voltage conditions you hope + + align:start position:0% +forward bias voltage conditions you hope + + + align:start position:0% +forward bias voltage conditions you hope +that you design your solar cell in such + + align:start position:0% +that you design your solar cell in such + + + align:start position:0% +that you design your solar cell in such +a way that the series resistance only + + align:start position:0% +a way that the series resistance only + + + align:start position:0% +a way that the series resistance only +really begins to kick in above the + + align:start position:0% +really begins to kick in above the + + + align:start position:0% +really begins to kick in above the +maximum PowerPoint + + align:start position:0% +maximum PowerPoint + + + align:start position:0% +maximum PowerPoint +voltage that's the goal and this is this + + align:start position:0% +voltage that's the goal and this is this + + + align:start position:0% +voltage that's the goal and this is this +is not voltage out this is voltage + + align:start position:0% +is not voltage out this is voltage + + + align:start position:0% +is not voltage out this is voltage +applied to the battery uh no this is + + align:start position:0% +applied to the battery uh no this is + + + align:start position:0% +applied to the battery uh no this is +this is the voltage uh that is is is + + align:start position:0% +this is the voltage uh that is is is + + + align:start position:0% +this is the voltage uh that is is is +being measured across the solar cell + + align:start position:0% +being measured across the solar cell + + + align:start position:0% +being measured across the solar cell +outut the output voltage yeah mhm or the + + align:start position:0% +outut the output voltage yeah mhm or the + + + align:start position:0% +outut the output voltage yeah mhm or the +yes the the the um + + align:start position:0% +yes the the the um + + + align:start position:0% +yes the the the um +you can think of this as as the uh the + + align:start position:0% +you can think of this as as the uh the + + + align:start position:0% +you can think of this as as the uh the +biasing condition of your solar cell + + align:start position:0% +biasing condition of your solar cell + + + align:start position:0% +biasing condition of your solar cell +device the two are almost equivalent the + + align:start position:0% +device the two are almost equivalent the + + + align:start position:0% +device the two are almost equivalent the +only difference is you have that series + + align:start position:0% +only difference is you have that series + + + align:start position:0% +only difference is you have that series +resistance in series there so you have + + align:start position:0% +resistance in series there so you have + + + align:start position:0% +resistance in series there so you have +to be careful whether you're talking + + align:start position:0% +to be careful whether you're talking + + + align:start position:0% +to be careful whether you're talking +about the uh voltage here at the solar + + align:start position:0% +about the uh voltage here at the solar + + + align:start position:0% +about the uh voltage here at the solar +cell itself across a junction uh or the + + align:start position:0% +cell itself across a junction uh or the + + + align:start position:0% +cell itself across a junction uh or the +voltage coming out of your device uh + + align:start position:0% +voltage coming out of your device uh + + + align:start position:0% +voltage coming out of your device uh +that is affected by that series + + align:start position:0% +that is affected by that series + + + align:start position:0% +that is affected by that series +resistance as + + align:start position:0% +resistance as + + + align:start position:0% +resistance as +well so think of it as uh doing that IV + + align:start position:0% +well so think of it as uh doing that IV + + + align:start position:0% +well so think of it as uh doing that IV +sweep that we did in class the other day + + align:start position:0% +sweep that we did in class the other day + + + align:start position:0% +sweep that we did in class the other day +right so you're taking the IV sweep of + + align:start position:0% +right so you're taking the IV sweep of + + + align:start position:0% +right so you're taking the IV sweep of +your device and you're seeing the impact + + align:start position:0% +your device and you're seeing the impact + + + align:start position:0% +your device and you're seeing the impact +of the series resistance in the output + + align:start position:0% +of the series resistance in the output + + + align:start position:0% +of the series resistance in the output +voltage that you're measuring of your + + align:start position:0% +voltage that you're measuring of your + + + align:start position:0% +voltage that you're measuring of your +solar cell device just like we did in + + align:start position:0% +solar cell device just like we did in + + + align:start position:0% +solar cell device just like we did in +class so again uh series resistance will + + align:start position:0% +class so again uh series resistance will + + + align:start position:0% +class so again uh series resistance will +affect you at some point it is almost + + align:start position:0% +affect you at some point it is almost + + + align:start position:0% +affect you at some point it is almost +inevitable but you have to design your + + align:start position:0% +inevitable but you have to design your + + + align:start position:0% +inevitable but you have to design your +solar cell such that it affects you only + + align:start position:0% +solar cell such that it affects you only + + + align:start position:0% +solar cell such that it affects you only +after the maximum power + + align:start position:0% +after the maximum power + + + align:start position:0% +after the maximum power +point likewise we're going to introduce + + align:start position:0% +point likewise we're going to introduce + + + align:start position:0% +point likewise we're going to introduce +another resistance term inside of our + + align:start position:0% +another resistance term inside of our + + + align:start position:0% +another resistance term inside of our +equivalent circuit diagram what we call + + align:start position:0% +equivalent circuit diagram what we call + + + align:start position:0% +equivalent circuit diagram what we call +a shunt resistance let me back up one + + align:start position:0% +a shunt resistance let me back up one + + + align:start position:0% +a shunt resistance let me back up one +step here this was just with series + + align:start position:0% +step here this was just with series + + + align:start position:0% +step here this was just with series +resistance now I've added a shunt + + align:start position:0% +resistance now I've added a shunt + + + align:start position:0% +resistance now I've added a shunt +resistance term here as well + + align:start position:0% +resistance term here as well + + + align:start position:0% +resistance term here as well +and whereas we wanted our our series + + align:start position:0% +and whereas we wanted our our series + + + align:start position:0% +and whereas we wanted our our series +resistance to be small right the smaller + + align:start position:0% +resistance to be small right the smaller + + + align:start position:0% +resistance to be small right the smaller +our series resistance the smaller our + + align:start position:0% +our series resistance the smaller our + + + align:start position:0% +our series resistance the smaller our +series resistance the less this effect + + align:start position:0% +series resistance the less this effect + + + align:start position:0% +series resistance the less this effect +would be the more ideal this curve would + + align:start position:0% +would be the more ideal this curve would + + + align:start position:0% +would be the more ideal this curve would +be we want our shunt resistance to be + + align:start position:0% +be we want our shunt resistance to be + + + align:start position:0% +be we want our shunt resistance to be +large because we want to prevent the + + align:start position:0% +large because we want to prevent the + + + align:start position:0% +large because we want to prevent the +current from flowing inside of the + + align:start position:0% +current from flowing inside of the + + + align:start position:0% +current from flowing inside of the +device and back to uh back to the the + + align:start position:0% +device and back to uh back to the the + + + align:start position:0% +device and back to uh back to the the +base instead we want the current to flow + + align:start position:0% +base instead we want the current to flow + + + align:start position:0% +base instead we want the current to flow +through the external circuit so we want + + align:start position:0% +through the external circuit so we want + + + align:start position:0% +through the external circuit so we want +the shunt resistance to be large in + + align:start position:0% +the shunt resistance to be large in + + + align:start position:0% +the shunt resistance to be large in +other words we don't want our solar cell + + align:start position:0% +other words we don't want our solar cell + + + align:start position:0% +other words we don't want our solar cell +device to be full of shunts that's + + align:start position:0% +device to be full of shunts that's + + + align:start position:0% +device to be full of shunts that's +pretty obvious okay so what does shunt + + align:start position:0% +pretty obvious okay so what does shunt + + + align:start position:0% +pretty obvious okay so what does shunt +resistance do to you well if we compare + + align:start position:0% +resistance do to you well if we compare + + + align:start position:0% +resistance do to you well if we compare +the IV curves once again uh between the + + align:start position:0% +the IV curves once again uh between the + + + align:start position:0% +the IV curves once again uh between the +solar cell just with the series + + align:start position:0% +solar cell just with the series + + + align:start position:0% +solar cell just with the series +resistance we had a very uh low uh uh + + align:start position:0% +resistance we had a very uh low uh uh + + + align:start position:0% +resistance we had a very uh low uh uh +forward current here under under low + + align:start position:0% +forward current here under under low + + + align:start position:0% +forward current here under under low +forward bias conditions if we have a a + + align:start position:0% +forward bias conditions if we have a a + + + align:start position:0% +forward bias conditions if we have a a +very poor shunt uh if we have a plethora + + align:start position:0% +very poor shunt uh if we have a plethora + + + align:start position:0% +very poor shunt uh if we have a plethora +of shunt Pathways in our device we're + + align:start position:0% +of shunt Pathways in our device we're + + + align:start position:0% +of shunt Pathways in our device we're +going to get current flowing through our + + align:start position:0% +going to get current flowing through our + + + align:start position:0% +going to get current flowing through our +device even at low uh bias conditions + + align:start position:0% +device even at low uh bias conditions + + + align:start position:0% +device even at low uh bias conditions +that's because the p injunction is weak + + align:start position:0% +that's because the p injunction is weak + + + align:start position:0% +that's because the p injunction is weak +and even though we have a very large + + align:start position:0% +and even though we have a very large + + + align:start position:0% +and even though we have a very large +field in there there are some regions + + align:start position:0% +field in there there are some regions + + + align:start position:0% +field in there there are some regions +where the field is much smaller because + + align:start position:0% +where the field is much smaller because + + + align:start position:0% +where the field is much smaller because +of the shunt pathway and current is + + align:start position:0% +of the shunt pathway and current is + + + align:start position:0% +of the shunt pathway and current is +going to be flowing through there + + align:start position:0% +going to be flowing through there + + + align:start position:0% +going to be flowing through there +diffusion current will be flowing + + align:start position:0% +diffusion current will be flowing + + + align:start position:0% +diffusion current will be flowing +through that shunt pathway so think of + + align:start position:0% +through that shunt pathway so think of + + + align:start position:0% +through that shunt pathway so think of +this as being a very strong diode right + + align:start position:0% +this as being a very strong diode right + + + align:start position:0% +this as being a very strong diode right +in the absence of shunt resistance you + + align:start position:0% +in the absence of shunt resistance you + + + align:start position:0% +in the absence of shunt resistance you +have a very strong diode you have uh in + + align:start position:0% +have a very strong diode you have uh in + + + align:start position:0% +have a very strong diode you have uh in +your p p type region in your n and that + + align:start position:0% +your p p type region in your n and that + + + align:start position:0% +your p p type region in your n and that +large barrier is preventing the + + align:start position:0% +large barrier is preventing the + + + align:start position:0% +large barrier is preventing the +diffusion of electrons back into the + + align:start position:0% +diffusion of electrons back into the + + + align:start position:0% +diffusion of electrons back into the +device it's preventing this from rising + + align:start position:0% +device it's preventing this from rising + + + align:start position:0% +device it's preventing this from rising +keeping it low and and that can only + + align:start position:0% +keeping it low and and that can only + + + align:start position:0% +keeping it low and and that can only +happen when the p and Junction uh + + align:start position:0% +happen when the p and Junction uh + + + align:start position:0% +happen when the p and Junction uh +barrier is uniform throughout your + + align:start position:0% +barrier is uniform throughout your + + + align:start position:0% +barrier is uniform throughout your +entire device if you have one region of + + align:start position:0% +entire device if you have one region of + + + align:start position:0% +entire device if you have one region of +your device that is poor that has a + + align:start position:0% +your device that is poor that has a + + + align:start position:0% +your device that is poor that has a +shunt pathway maybe you have a piece of + + align:start position:0% +shunt pathway maybe you have a piece of + + + align:start position:0% +shunt pathway maybe you have a piece of +metal that fired through the junction + + align:start position:0% +metal that fired through the junction + + + align:start position:0% +metal that fired through the junction +and is making good omic contact to both + + align:start position:0% +and is making good omic contact to both + + + align:start position:0% +and is making good omic contact to both +sides if you have a shunt pathway now + + align:start position:0% +sides if you have a shunt pathway now + + + align:start position:0% +sides if you have a shunt pathway now +the current can flow even under small + + align:start position:0% +the current can flow even under small + + + align:start position:0% +the current can flow even under small +bias conditions the diffusion current + + align:start position:0% +bias conditions the diffusion current + + + align:start position:0% +bias conditions the diffusion current +can flow into your device and that of + + align:start position:0% +can flow into your device and that of + + + align:start position:0% +can flow into your device and that of +course uh drops on on on on the linear + + align:start position:0% +course uh drops on on on on the linear + + + align:start position:0% +course uh drops on on on on the linear +log scale right up here you hardly + + align:start position:0% +log scale right up here you hardly + + + align:start position:0% +log scale right up here you hardly +detect it notice if we go back and forth + + align:start position:0% +detect it notice if we go back and forth + + + align:start position:0% +detect it notice if we go back and forth +between with and without shunt + + align:start position:0% +between with and without shunt + + + align:start position:0% +between with and without shunt +resistance you can hardly detect it + + align:start position:0% +resistance you can hardly detect it + + + align:start position:0% +resistance you can hardly detect it +right here until you start getting to + + align:start position:0% +right here until you start getting to + + + align:start position:0% +right here until you start getting to +some really leaky diodes in which case + + align:start position:0% +some really leaky diodes in which case + + + align:start position:0% +some really leaky diodes in which case +you begin to impact your fill Factor as + + align:start position:0% +you begin to impact your fill Factor as + + + align:start position:0% +you begin to impact your fill Factor as +well so shunt resistance is is important + + align:start position:0% +well so shunt resistance is is important + + + align:start position:0% +well so shunt resistance is is important +for a solar cell device that it not be + + align:start position:0% +for a solar cell device that it not be + + + align:start position:0% +for a solar cell device that it not be +too too high um because at some point it + + align:start position:0% +too too high um because at some point it + + + align:start position:0% +too too high um because at some point it +does begin impacting your fill factor + + align:start position:0% +does begin impacting your fill factor + + + align:start position:0% +does begin impacting your fill factor +sorry the shunt resistance not be too + + align:start position:0% +sorry the shunt resistance not be too + + + align:start position:0% +sorry the shunt resistance not be too +too too low yes uh your shun resistance + + align:start position:0% +too too low yes uh your shun resistance + + + align:start position:0% +too too low yes uh your shun resistance +can't be too too low because at some + + align:start position:0% +can't be too too low because at some + + + align:start position:0% +can't be too too low because at some +point it will begin impacting your fill + + align:start position:0% +point it will begin impacting your fill + + + align:start position:0% +point it will begin impacting your fill +Factor but more importantly shunt + + align:start position:0% +Factor but more importantly shunt + + + align:start position:0% +Factor but more importantly shunt +resistance is usually indicative of some + + align:start position:0% +resistance is usually indicative of some + + + align:start position:0% +resistance is usually indicative of some +localized failure in your PN Jun it's + + align:start position:0% +localized failure in your PN Jun it's + + + align:start position:0% +localized failure in your PN Jun it's +usually not homogeneously distributed + + align:start position:0% +usually not homogeneously distributed + + + align:start position:0% +usually not homogeneously distributed +throughout the entire pan Junction maybe + + align:start position:0% +throughout the entire pan Junction maybe + + + align:start position:0% +throughout the entire pan Junction maybe +your first solar cell device you ever + + align:start position:0% +your first solar cell device you ever + + + align:start position:0% +your first solar cell device you ever +make might be affected by that but as + + align:start position:0% +make might be affected by that but as + + + align:start position:0% +make might be affected by that but as +you get better and better you'll you'll + + align:start position:0% +you get better and better you'll you'll + + + align:start position:0% +you get better and better you'll you'll +you'll start making higher quality + + align:start position:0% +you'll start making higher quality + + + align:start position:0% +you'll start making higher quality +Junctions and usually the shunt + + align:start position:0% +Junctions and usually the shunt + + + align:start position:0% +Junctions and usually the shunt +resistance is indicative of of one + + align:start position:0% +resistance is indicative of of one + + + align:start position:0% +resistance is indicative of of one +little spot and what happens at that one + + align:start position:0% +little spot and what happens at that one + + + align:start position:0% +little spot and what happens at that one +little spot well current is flowing in + + align:start position:0% +little spot well current is flowing in + + + align:start position:0% +little spot well current is flowing in +from the entire emitter region into that + + align:start position:0% +from the entire emitter region into that + + + align:start position:0% +from the entire emitter region into that +one little shunt and locally heating up + + align:start position:0% +one little shunt and locally heating up + + + align:start position:0% +one little shunt and locally heating up +your device and so that's why people + + align:start position:0% +your device and so that's why people + + + align:start position:0% +your device and so that's why people +worry about shunts in industry is + + align:start position:0% +worry about shunts in industry is + + + align:start position:0% +worry about shunts in industry is +because if you have current crowding + + align:start position:0% +because if you have current crowding + + + align:start position:0% +because if you have current crowding +into that one little spot it's heating + + align:start position:0% +into that one little spot it's heating + + + align:start position:0% +into that one little spot it's heating +up it's becoming a hot spot and it can + + align:start position:0% +up it's becoming a hot spot and it can + + + align:start position:0% +up it's becoming a hot spot and it can +even melt the encapsulate materials in + + align:start position:0% +even melt the encapsulate materials in + + + align:start position:0% +even melt the encapsulate materials in +your module perhaps even uh create a a + + align:start position:0% +your module perhaps even uh create a a + + + align:start position:0% +your module perhaps even uh create a a +fire in extreme conditions and so uh + + align:start position:0% +fire in extreme conditions and so uh + + + align:start position:0% +fire in extreme conditions and so uh +when you test the solar cell devices um + + align:start position:0% +when you test the solar cell devices um + + + align:start position:0% +when you test the solar cell devices um +typically the IV tester will throw out + + align:start position:0% +typically the IV tester will throw out + + + align:start position:0% +typically the IV tester will throw out +uh well will will measure the shunt + + align:start position:0% +uh well will will measure the shunt + + + align:start position:0% +uh well will will measure the shunt +resistance in a solar cell by looking at + + align:start position:0% +resistance in a solar cell by looking at + + + align:start position:0% +resistance in a solar cell by looking at +what's happening under very small bias + + align:start position:0% +what's happening under very small bias + + + align:start position:0% +what's happening under very small bias +conditions right here and comparing it + + align:start position:0% +conditions right here and comparing it + + + align:start position:0% +conditions right here and comparing it +against the healthy cell that it would + + align:start position:0% +against the healthy cell that it would + + + align:start position:0% +against the healthy cell that it would +expect and if it finds cells with high + + align:start position:0% +expect and if it finds cells with high + + + align:start position:0% +expect and if it finds cells with high +uh shunt leakage current in other words + + align:start position:0% +uh shunt leakage current in other words + + + align:start position:0% +uh shunt leakage current in other words +low shunt resistance it will advise the + + align:start position:0% +low shunt resistance it will advise the + + + align:start position:0% +low shunt resistance it will advise the +the the tester and sorder to throw out + + align:start position:0% +the the tester and sorder to throw out + + + align:start position:0% +the the tester and sorder to throw out +those cells and so they'll be put into + + align:start position:0% +those cells and so they'll be put into + + + align:start position:0% +those cells and so they'll be put into +the scrap + + align:start position:0% +the scrap + + + align:start position:0% +the scrap +pile and so the shunt resistance + + align:start position:0% +pile and so the shunt resistance + + + align:start position:0% +pile and so the shunt resistance +manifests itself right here in the ideal + + align:start position:0% +manifests itself right here in the ideal + + + align:start position:0% +manifests itself right here in the ideal +diode equation uh in this term right + + align:start position:0% +diode equation uh in this term right + + + align:start position:0% +diode equation uh in this term right +there so it's essentially in add- on + + align:start position:0% +there so it's essentially in add- on + + + align:start position:0% +there so it's essentially in add- on +term after your exponential uh looking + + align:start position:0% +term after your exponential uh looking + + + align:start position:0% +term after your exponential uh looking +something like this essentially at uh + + align:start position:0% +something like this essentially at uh + + + align:start position:0% +something like this essentially at uh +low bias conditions you can extrapolate + + align:start position:0% +low bias conditions you can extrapolate + + + align:start position:0% +low bias conditions you can extrapolate +this point right here determine the + + align:start position:0% +this point right here determine the + + + align:start position:0% +this point right here determine the +slope of that point and find uh the + + align:start position:0% +slope of that point and find uh the + + + align:start position:0% +slope of that point and find uh the +shunt + + align:start position:0% + + + + align:start position:0% + +resistance and uh likewise you'll notice + + align:start position:0% +resistance and uh likewise you'll notice + + + align:start position:0% +resistance and uh likewise you'll notice +that the shunt resistance really isn't + + align:start position:0% +that the shunt resistance really isn't + + + align:start position:0% +that the shunt resistance really isn't +impacting you up + + align:start position:0% +impacting you up + + + align:start position:0% +impacting you up +here uh the the shunt resistance really + + align:start position:0% +here uh the the shunt resistance really + + + align:start position:0% +here uh the the shunt resistance really +isn't impacting you at higher forward + + align:start position:0% +isn't impacting you at higher forward + + + align:start position:0% +isn't impacting you at higher forward +bias conditions uh that's mostly series + + align:start position:0% +bias conditions uh that's mostly series + + + align:start position:0% +bias conditions uh that's mostly series +resistance and the illumination current + + align:start position:0% +resistance and the illumination current + + + align:start position:0% +resistance and the illumination current +that's overwhelming uh any shun pathway + + align:start position:0% +that's overwhelming uh any shun pathway + + + align:start position:0% +that's overwhelming uh any shun pathway +Ashley yeah do you know for for I don't + + align:start position:0% +Ashley yeah do you know for for I don't + + + align:start position:0% +Ashley yeah do you know for for I don't +know a high quality manufacturer how + + align:start position:0% +know a high quality manufacturer how + + + align:start position:0% +know a high quality manufacturer how +what percentage of produced cells get + + align:start position:0% +what percentage of produced cells get + + + align:start position:0% +what percentage of produced cells get +tossed because of very low the uh + + align:start position:0% +tossed because of very low the uh + + + align:start position:0% +tossed because of very low the uh +manufacturing yields of um a well oiled + + align:start position:0% +manufacturing yields of um a well oiled + + + align:start position:0% +manufacturing yields of um a well oiled +manufacturing line I I say oiled in a + + align:start position:0% +manufacturing line I I say oiled in a + + + align:start position:0% +manufacturing line I I say oiled in a +figurative sense we're not typically + + align:start position:0% +figurative sense we're not typically + + + align:start position:0% +figurative sense we're not typically +yeah some of the parts I suppose use oil + + align:start position:0% +yeah some of the parts I suppose use oil + + + align:start position:0% +yeah some of the parts I suppose use oil +um we in in a well functioning + + align:start position:0% +um we in in a well functioning + + + align:start position:0% +um we in in a well functioning +manufacuring line uh the yields are + + align:start position:0% +manufacuring line uh the yields are + + + align:start position:0% +manufacuring line uh the yields are +upwards of 95% for sell fabrication so + + align:start position:0% +upwards of 95% for sell fabrication so + + + align:start position:0% +upwards of 95% for sell fabrication so +it's a very small percentage uh you + + align:start position:0% +it's a very small percentage uh you + + + align:start position:0% +it's a very small percentage uh you +typically see this when you're + + align:start position:0% +typically see this when you're + + + align:start position:0% +typically see this when you're +developing a new process and that's why + + align:start position:0% +developing a new process and that's why + + + align:start position:0% +developing a new process and that's why +I'm informing all of you about this is + + align:start position:0% +I'm informing all of you about this is + + + align:start position:0% +I'm informing all of you about this is +because we're all developing new + + align:start position:0% +because we're all developing new + + + align:start position:0% +because we're all developing new +processes here right we're all working + + align:start position:0% +processes here right we're all working + + + align:start position:0% +processes here right we're all working +on new solar cell devices and it's it's + + align:start position:0% +on new solar cell devices and it's it's + + + align:start position:0% +on new solar cell devices and it's it's +very important to be aware of of of + + align:start position:0% +very important to be aware of of of + + + align:start position:0% +very important to be aware of of of +what's going wrong in your device not + + align:start position:0% +what's going wrong in your device not + + + align:start position:0% +what's going wrong in your device not +just that you're getting a low + + align:start position:0% +just that you're getting a low + + + align:start position:0% +just that you're getting a low +efficiency because this is a first step + + align:start position:0% +efficiency because this is a first step + + + align:start position:0% +efficiency because this is a first step +to troubleshooting y this why is it bad + + align:start position:0% +to troubleshooting y this why is it bad + + + align:start position:0% +to troubleshooting y this why is it bad +that we have a high current density is + + align:start position:0% +that we have a high current density is + + + align:start position:0% +that we have a high current density is +not the current density going AC uh why + + align:start position:0% +not the current density going AC uh why + + + align:start position:0% +not the current density going AC uh why +is it bad that we have a high current + + align:start position:0% +is it bad that we have a high current + + + align:start position:0% +is it bad that we have a high current +density why don't we go back to a simple + + align:start position:0% +density why don't we go back to a simple + + + align:start position:0% +density why don't we go back to a simple +case right here where we have uh series + + align:start position:0% +case right here where we have uh series + + + align:start position:0% +case right here where we have uh series +resistance for instance right and so at + + align:start position:0% +resistance for instance right and so at + + + align:start position:0% +resistance for instance right and so at +at say 0.5 volts forward bias we now + + align:start position:0% +at say 0.5 volts forward bias we now + + + align:start position:0% +at say 0.5 volts forward bias we now +have with the series resistance a higher + + align:start position:0% +have with the series resistance a higher + + + align:start position:0% +have with the series resistance a higher +uh forward current we'll call it a dark + + align:start position:0% +uh forward current we'll call it a dark + + + align:start position:0% +uh forward current we'll call it a dark +forward current because we're measuring + + align:start position:0% +forward current because we're measuring + + + align:start position:0% +forward current because we're measuring +this in the dark that's why we have zero + + align:start position:0% +this in the dark that's why we have zero + + + align:start position:0% +this in the dark that's why we have zero +here and it's forward current meaning + + align:start position:0% +here and it's forward current meaning + + + align:start position:0% +here and it's forward current meaning +it's going it's like a diffusion current + + align:start position:0% +it's going it's like a diffusion current + + + align:start position:0% +it's going it's like a diffusion current +going from the emitter back into the + + align:start position:0% +going from the emitter back into the + + + align:start position:0% +going from the emitter back into the +base um and so we have a higher dark + + align:start position:0% +base um and so we have a higher dark + + + align:start position:0% +base um and so we have a higher dark +forward current here in the dark with + + align:start position:0% +forward current here in the dark with + + + align:start position:0% +forward current here in the dark with +the series resistance than if we didn't + + align:start position:0% +the series resistance than if we didn't + + + align:start position:0% +the series resistance than if we didn't +have the series resistance right so let + + align:start position:0% +have the series resistance right so let + + + align:start position:0% +have the series resistance right so let +me do that again we're up here at say uh + + align:start position:0% +me do that again we're up here at say uh + + + align:start position:0% +me do that again we're up here at say uh +1 * 10us 2 milliamps per CM whereas + + align:start position:0% +1 * 10us 2 milliamps per CM whereas + + + align:start position:0% +1 * 10us 2 milliamps per CM whereas +before we were down at around maybe a + + align:start position:0% +before we were down at around maybe a + + + align:start position:0% +before we were down at around maybe a +quarter right so why is that bad that's + + align:start position:0% +quarter right so why is that bad that's + + + align:start position:0% +quarter right so why is that bad that's +bad because when we illuminate our solar + + align:start position:0% +bad because when we illuminate our solar + + + align:start position:0% +bad because when we illuminate our solar +cell device we are going to be shifting + + align:start position:0% +cell device we are going to be shifting + + + align:start position:0% +cell device we are going to be shifting +that curve down and that's going to + + align:start position:0% +that curve down and that's going to + + + align:start position:0% +that curve down and that's going to +reduce the total current output at the + + align:start position:0% +reduce the total current output at the + + + align:start position:0% +reduce the total current output at the +maximum power point so anything that + + align:start position:0% +maximum power point so anything that + + + align:start position:0% +maximum power point so anything that +goes up here when it's shifted or + + align:start position:0% +goes up here when it's shifted or + + + align:start position:0% +goes up here when it's shifted or +transposed by a finite fixed amount it + + align:start position:0% +transposed by a finite fixed amount it + + + align:start position:0% +transposed by a finite fixed amount it +will be closer to the zero point of + + align:start position:0% +will be closer to the zero point of + + + align:start position:0% +will be closer to the zero point of +current than it used to be that's why + + align:start position:0% +current than it used to be that's why + + + align:start position:0% +current than it used to be that's why +it's bad so anything anything that + + align:start position:0% +it's bad so anything anything that + + + align:start position:0% +it's bad so anything anything that +increases um that blue curve and shifts + + align:start position:0% +increases um that blue curve and shifts + + + align:start position:0% +increases um that blue curve and shifts +it up in the dark is going to be bad for + + align:start position:0% +it up in the dark is going to be bad for + + + align:start position:0% +it up in the dark is going to be bad for +our solar cell in an ideal case we want + + align:start position:0% +our solar cell in an ideal case we want + + + align:start position:0% +our solar cell in an ideal case we want +our dark forward current to be as small + + align:start position:0% +our dark forward current to be as small + + + align:start position:0% +our dark forward current to be as small +as possible we want our J knot to be as + + align:start position:0% +as possible we want our J knot to be as + + + align:start position:0% +as possible we want our J knot to be as +Tiny as + + align:start position:0% +Tiny as + + + align:start position:0% +Tiny as +possible for a good solar cell + + align:start position:0% + + + + align:start position:0% + +device + + align:start position:0% + + + + align:start position:0% + +okay good let me uh show you dynamically + + align:start position:0% +okay good let me uh show you dynamically + + + align:start position:0% +okay good let me uh show you dynamically +what happens um in a solar cell oopsie + + align:start position:0% +what happens um in a solar cell oopsie + + + align:start position:0% +what happens um in a solar cell oopsie +sorry about that here we go so this is + + align:start position:0% +sorry about that here we go so this is + + + align:start position:0% +sorry about that here we go so this is +uh pbcd Raman uh and a beautiful example + + align:start position:0% +uh pbcd Raman uh and a beautiful example + + + align:start position:0% +uh pbcd Raman uh and a beautiful example +of in this particular case looks like + + align:start position:0% +of in this particular case looks like + + + align:start position:0% +of in this particular case looks like +series resistance so now we're at 1 ohm + + align:start position:0% +series resistance so now we're at 1 ohm + + + align:start position:0% +series resistance so now we're at 1 ohm +series resistance for the entire device + + align:start position:0% +series resistance for the entire device + + + align:start position:0% +series resistance for the entire device +the ideal solar cell is shown in red the + + align:start position:0% +the ideal solar cell is shown in red the + + + align:start position:0% +the ideal solar cell is shown in red the +IV curve for the ideal solar cell is + + align:start position:0% +IV curve for the ideal solar cell is + + + align:start position:0% +IV curve for the ideal solar cell is +shown in red uh it would be a short + + align:start position:0% +shown in red uh it would be a short + + + align:start position:0% +shown in red uh it would be a short +circuit current of 35 milliamps per + + align:start position:0% +circuit current of 35 milliamps per + + + align:start position:0% +circuit current of 35 milliamps per +square cimeter an open circuit voltage + + align:start position:0% +square cimeter an open circuit voltage + + + align:start position:0% +square cimeter an open circuit voltage +of 624 molts and a fill factor of 83% + + align:start position:0% +of 624 molts and a fill factor of 83% + + + align:start position:0% +of 624 molts and a fill factor of 83% +ideal solar cell the real solar cell now + + align:start position:0% +ideal solar cell the real solar cell now + + + align:start position:0% +ideal solar cell the real solar cell now +with 1 ohm series resistance The Fill + + align:start position:0% +with 1 ohm series resistance The Fill + + + align:start position:0% +with 1 ohm series resistance The Fill +Factor has dropped by 5% down absolute + + align:start position:0% +Factor has dropped by 5% down absolute + + + align:start position:0% +Factor has dropped by 5% down absolute +down to + + align:start position:0% +down to + + + align:start position:0% +down to +78% and now I'm going to increase the + + align:start position:0% +78% and now I'm going to increase the + + + align:start position:0% +78% and now I'm going to increase the +fill Factor what would you expect to + + align:start position:0% +fill Factor what would you expect to + + + align:start position:0% +fill Factor what would you expect to +happen to that + + align:start position:0% + + + + align:start position:0% + +curve flattens right the fill Factor + + align:start position:0% +curve flattens right the fill Factor + + + align:start position:0% +curve flattens right the fill Factor +drops so let me start increasing the + + align:start position:0% +drops so let me start increasing the + + + align:start position:0% +drops so let me start increasing the +series resistance by manually dragging + + align:start position:0% +series resistance by manually dragging + + + align:start position:0% +series resistance by manually dragging +this forward so now we're at around + + align:start position:0% +this forward so now we're at around + + + align:start position:0% +this forward so now we're at around +two 3 4 five 7 8 9 10 so now we're at 10 + + align:start position:0% +two 3 4 five 7 8 9 10 so now we're at 10 + + + align:start position:0% +two 3 4 five 7 8 9 10 so now we're at 10 +ohms series resistance that means we + + align:start position:0% +ohms series resistance that means we + + + align:start position:0% +ohms series resistance that means we +have a large resistance across inside of + + align:start position:0% +have a large resistance across inside of + + + align:start position:0% +have a large resistance across inside of +our solar cell device at some point and + + align:start position:0% +our solar cell device at some point and + + + align:start position:0% +our solar cell device at some point and +our fill Factor has now dropped uh + + align:start position:0% +our fill Factor has now dropped uh + + + align:start position:0% +our fill Factor has now dropped uh +precipitously and if you remember that + + align:start position:0% +precipitously and if you remember that + + + align:start position:0% +precipitously and if you remember that +efficiency is proportional to fill + + align:start position:0% +efficiency is proportional to fill + + + align:start position:0% +efficiency is proportional to fill +factor that means we have a problem with + + align:start position:0% +factor that means we have a problem with + + + align:start position:0% +factor that means we have a problem with +our device we're really dropping the + + align:start position:0% +our device we're really dropping the + + + align:start position:0% +our device we're really dropping the +maximum power point we're really + + align:start position:0% +maximum power point we're really + + + align:start position:0% +maximum power point we're really +dropping the uh operating point of our + + align:start position:0% +dropping the uh operating point of our + + + align:start position:0% +dropping the uh operating point of our +solar cell so the if you were to do an + + align:start position:0% +solar cell so the if you were to do an + + + align:start position:0% +solar cell so the if you were to do an +extreme condition um you know you you + + align:start position:0% +extreme condition um you know you you + + + align:start position:0% +extreme condition um you know you you +you might have so much serious + + align:start position:0% +you might have so much serious + + + align:start position:0% +you might have so much serious +resistance that your IV curve looks like + + align:start position:0% +resistance that your IV curve looks like + + + align:start position:0% +resistance that your IV curve looks like +a straight line you have an omic + + align:start position:0% +a straight line you have an omic + + + align:start position:0% +a straight line you have an omic +resistor now + + align:start position:0% +resistor now + + + align:start position:0% +resistor now +the uh resistance component is swamping + + align:start position:0% +the uh resistance component is swamping + + + align:start position:0% +the uh resistance component is swamping +out any diod likee behavior of a solar + + align:start position:0% +out any diod likee behavior of a solar + + + align:start position:0% +out any diod likee behavior of a solar +cell and that's why you have a line + + align:start position:0% +cell and that's why you have a line + + + align:start position:0% +cell and that's why you have a line +likewise you're dropping the total + + align:start position:0% +likewise you're dropping the total + + + align:start position:0% +likewise you're dropping the total +current output of your device right + + align:start position:0% +current output of your device right + + + align:start position:0% +current output of your device right +because you have a resistor in series + + align:start position:0% +because you have a resistor in series + + + align:start position:0% +because you have a resistor in series +now is preventing the current flow okay + + align:start position:0% +now is preventing the current flow okay + + + align:start position:0% +now is preventing the current flow okay +so that's um again an extreme case of + + align:start position:0% +so that's um again an extreme case of + + + align:start position:0% +so that's um again an extreme case of +what can happen in a shunt resistance uh + + align:start position:0% +what can happen in a shunt resistance uh + + + align:start position:0% +what can happen in a shunt resistance uh +let me show you that as well so we have + + align:start position:0% +let me show you that as well so we have + + + align:start position:0% +let me show you that as well so we have +another beautiful uh example of shunt + + align:start position:0% +another beautiful uh example of shunt + + + align:start position:0% +another beautiful uh example of shunt +resistance um here now we start out with + + align:start position:0% +resistance um here now we start out with + + + align:start position:0% +resistance um here now we start out with +a very high shunt resistance because in + + align:start position:0% +a very high shunt resistance because in + + + align:start position:0% +a very high shunt resistance because in +our equivalent circuit diagram if we go + + align:start position:0% +our equivalent circuit diagram if we go + + + align:start position:0% +our equivalent circuit diagram if we go +back up here we have a large barrier + + align:start position:0% +back up here we have a large barrier + + + align:start position:0% +back up here we have a large barrier +that prevents the current from flowing + + align:start position:0% +that prevents the current from flowing + + + align:start position:0% +that prevents the current from flowing +back internally inside of the device the + + align:start position:0% +back internally inside of the device the + + + align:start position:0% +back internally inside of the device the +current is forced to go outside through + + align:start position:0% +current is forced to go outside through + + + align:start position:0% +current is forced to go outside through +the external circuit but as we drop that + + align:start position:0% +the external circuit but as we drop that + + + align:start position:0% +the external circuit but as we drop that +red shunt resistance component right + + align:start position:0% +red shunt resistance component right + + + align:start position:0% +red shunt resistance component right +there as we uh decrease the magnitude of + + align:start position:0% +there as we uh decrease the magnitude of + + + align:start position:0% +there as we uh decrease the magnitude of +the shunt resistance we will allow the + + align:start position:0% +the shunt resistance we will allow the + + + align:start position:0% +the shunt resistance we will allow the +current to flow inside of the device now + + align:start position:0% +current to flow inside of the device now + + + align:start position:0% +current to flow inside of the device now +we have internal current loops and that + + align:start position:0% +we have internal current loops and that + + + align:start position:0% +we have internal current loops and that +means that we no longer are forcing the + + align:start position:0% +means that we no longer are forcing the + + + align:start position:0% +means that we no longer are forcing the +current to go outside through the + + align:start position:0% +current to go outside through the + + + align:start position:0% +current to go outside through the +external circuit and somewhere around uh + + align:start position:0% +external circuit and somewhere around uh + + + align:start position:0% +external circuit and somewhere around uh +between a th000 + + align:start position:0% +between a th000 + + + align:start position:0% +between a th000 +100 ohms for our shunt resistance we + + align:start position:0% +100 ohms for our shunt resistance we + + + align:start position:0% +100 ohms for our shunt resistance we +really begin to see that drop in fill + + align:start position:0% +really begin to see that drop in fill + + + align:start position:0% +really begin to see that drop in fill +factor and as expected it's really + + align:start position:0% +factor and as expected it's really + + + align:start position:0% +factor and as expected it's really +beginning to impact us at the lower bias + + align:start position:0% +beginning to impact us at the lower bias + + + align:start position:0% +beginning to impact us at the lower bias +voltages down here like we saw and at + + align:start position:0% +voltages down here like we saw and at + + + align:start position:0% +voltages down here like we saw and at +some point we dropped the shunt + + align:start position:0% +some point we dropped the shunt + + + align:start position:0% +some point we dropped the shunt +resistance so much that uh now the + + align:start position:0% +resistance so much that uh now the + + + align:start position:0% +resistance so much that uh now the +voltage across our solar cell is even + + align:start position:0% +voltage across our solar cell is even + + + align:start position:0% +voltage across our solar cell is even +suffering because there's uh not enough + + align:start position:0% +suffering because there's uh not enough + + + align:start position:0% +suffering because there's uh not enough +separation of charge sustained uh to + + align:start position:0% +separation of charge sustained uh to + + + align:start position:0% +separation of charge sustained uh to +make that voltage uh large because the + + align:start position:0% +make that voltage uh large because the + + + align:start position:0% +make that voltage uh large because the +current is being shunted back inside the + + align:start position:0% +current is being shunted back inside the + + + align:start position:0% +current is being shunted back inside the +device + + align:start position:0% +device + + + align:start position:0% +device +and again we we have what appears to be + + align:start position:0% +and again we we have what appears to be + + + align:start position:0% +and again we we have what appears to be +a very a linear IV curve so you can see + + align:start position:0% +a very a linear IV curve so you can see + + + align:start position:0% +a very a linear IV curve so you can see +when you when you measure your solar + + align:start position:0% +when you when you measure your solar + + + align:start position:0% +when you when you measure your solar +cell and you test it and you get a + + align:start position:0% +cell and you test it and you get a + + + align:start position:0% +cell and you test it and you get a +linear IV curve instead of that nice + + align:start position:0% +linear IV curve instead of that nice + + + align:start position:0% +linear IV curve instead of that nice +exponential you have to do a little bit + + align:start position:0% +exponential you have to do a little bit + + + align:start position:0% +exponential you have to do a little bit +of troubleshooting to figure out what + + align:start position:0% +of troubleshooting to figure out what + + + align:start position:0% +of troubleshooting to figure out what +exactly is going on + + align:start position:0% +exactly is going on + + + align:start position:0% +exactly is going on +okay + + align:start position:0% +okay + + + align:start position:0% +okay +good so uh key concept so far um we can + + align:start position:0% +good so uh key concept so far um we can + + + align:start position:0% +good so uh key concept so far um we can +add the effects of parallel resistance + + align:start position:0% +add the effects of parallel resistance + + + align:start position:0% +add the effects of parallel resistance +um what we typically refer to as shunt + + align:start position:0% +um what we typically refer to as shunt + + + align:start position:0% +um what we typically refer to as shunt +resistance is also called parallel + + align:start position:0% +resistance is also called parallel + + + align:start position:0% +resistance is also called parallel +resistance because uh it appears in + + align:start position:0% +resistance because uh it appears in + + + align:start position:0% +resistance because uh it appears in +parallel with our uh the diode inside of + + align:start position:0% +parallel with our uh the diode inside of + + + align:start position:0% +parallel with our uh the diode inside of +the device right so um we can have a + + align:start position:0% +the device right so um we can have a + + + align:start position:0% +the device right so um we can have a +parallel or shunt resistance and series + + align:start position:0% +parallel or shunt resistance and series + + + align:start position:0% +parallel or shunt resistance and series +resistance in our devices and as an + + align:start position:0% +resistance in our devices and as an + + + align:start position:0% +resistance in our devices and as an +advanced concept I really wanted to + + align:start position:0% +advanced concept I really wanted to + + + align:start position:0% +advanced concept I really wanted to +expose you once uh and we can talk more + + align:start position:0% +expose you once uh and we can talk more + + + align:start position:0% +expose you once uh and we can talk more +about this in in office hours um to the + + align:start position:0% +about this in in office hours um to the + + + align:start position:0% +about this in in office hours um to the +notion that in addition to uh just + + align:start position:0% +notion that in addition to uh just + + + align:start position:0% +notion that in addition to uh just +having one saturation current you could + + align:start position:0% +having one saturation current you could + + + align:start position:0% +having one saturation current you could +Envision different saturation currents + + align:start position:0% +Envision different saturation currents + + + align:start position:0% +Envision different saturation currents +coming from different regions of your + + align:start position:0% +coming from different regions of your + + + align:start position:0% +coming from different regions of your +solar cell device let me walk you + + align:start position:0% +solar cell device let me walk you + + + align:start position:0% +solar cell device let me walk you +through that under low bias conditions + + align:start position:0% +through that under low bias conditions + + + align:start position:0% +through that under low bias conditions +where we have a large uh uh uh built-in + + align:start position:0% +where we have a large uh uh uh built-in + + + align:start position:0% +where we have a large uh uh uh built-in +uh uh field and we have very low bias + + align:start position:0% +uh uh field and we have very low bias + + + align:start position:0% +uh uh field and we have very low bias +conditions as we for bias obviously the + + align:start position:0% +conditions as we for bias obviously the + + + align:start position:0% +conditions as we for bias obviously the +field is going to be decreasing the + + align:start position:0% +field is going to be decreasing the + + + align:start position:0% +field is going to be decreasing the +barrier height is going to be decreasing + + align:start position:0% +barrier height is going to be decreasing + + + align:start position:0% +barrier height is going to be decreasing +as well so under low forward bias + + align:start position:0% +as well so under low forward bias + + + align:start position:0% +as well so under low forward bias +conditions current is going to have a + + align:start position:0% +conditions current is going to have a + + + align:start position:0% +conditions current is going to have a +hard time getting all the way up into + + align:start position:0% +hard time getting all the way up into + + + align:start position:0% +hard time getting all the way up into +the base and recombining inside of the + + align:start position:0% +the base and recombining inside of the + + + align:start position:0% +the base and recombining inside of the +base but some of the current could + + align:start position:0% +base but some of the current could + + + align:start position:0% +base but some of the current could +recombine in the space charge region of + + align:start position:0% +recombine in the space charge region of + + + align:start position:0% +recombine in the space charge region of +our device and that's why under low + + align:start position:0% +our device and that's why under low + + + align:start position:0% +our device and that's why under low +forward bias conditions we might have + + align:start position:0% +forward bias conditions we might have + + + align:start position:0% +forward bias conditions we might have +what is called the jot2 current or + + align:start position:0% +what is called the jot2 current or + + + align:start position:0% +what is called the jot2 current or +recombination current in the space + + align:start position:0% +recombination current in the space + + + align:start position:0% +recombination current in the space +charge region and then the are high + + align:start position:0% +charge region and then the are high + + + align:start position:0% +charge region and then the are high +forward bias conditions when a lot of + + align:start position:0% +forward bias conditions when a lot of + + + align:start position:0% +forward bias conditions when a lot of +the carriers can diffuse into the bulk + + align:start position:0% +the carriers can diffuse into the bulk + + + align:start position:0% +the carriers can diffuse into the bulk +and recombine inside of the bulk we + + align:start position:0% +and recombine inside of the bulk we + + + align:start position:0% +and recombine inside of the bulk we +might be driven by different + + align:start position:0% +might be driven by different + + + align:start position:0% +might be driven by different +recombination mechanisms uh bulk + + align:start position:0% +recombination mechanisms uh bulk + + + align:start position:0% +recombination mechanisms uh bulk +recombination mechanisms so that's + + align:start position:0% +recombination mechanisms so that's + + + align:start position:0% +recombination mechanisms so that's +sometimes where you see uh what is + + align:start position:0% +sometimes where you see uh what is + + + align:start position:0% +sometimes where you see uh what is +called a two diode model for a solar + + align:start position:0% +called a two diode model for a solar + + + align:start position:0% +called a two diode model for a solar +cell and the two diode model for a solar + + align:start position:0% +cell and the two diode model for a solar + + + align:start position:0% +cell and the two diode model for a solar +cell would look very much like this + + align:start position:0% +cell would look very much like this + + + align:start position:0% +cell would look very much like this +except you'd have two two diodes uh one + + align:start position:0% +except you'd have two two diodes uh one + + + align:start position:0% +except you'd have two two diodes uh one +right next to the other um one that + + align:start position:0% +right next to the other um one that + + + align:start position:0% +right next to the other um one that +would affect you at low bias conditions + + align:start position:0% +would affect you at low bias conditions + + + align:start position:0% +would affect you at low bias conditions +the other one at large bias conditions + + align:start position:0% +the other one at large bias conditions + + + align:start position:0% +the other one at large bias conditions +you might see this in your research it's + + align:start position:0% +you might see this in your research it's + + + align:start position:0% +you might see this in your research it's +really an advanced concept more targeted + + align:start position:0% +really an advanced concept more targeted + + + align:start position:0% +really an advanced concept more targeted +toward the The Graduate students here + + align:start position:0% +toward the The Graduate students here + + + align:start position:0% +toward the The Graduate students here +another thing you might see Pop Up is + + align:start position:0% +another thing you might see Pop Up is + + + align:start position:0% +another thing you might see Pop Up is +this ideality Factor showing up right + + align:start position:0% +this ideality Factor showing up right + + + align:start position:0% +this ideality Factor showing up right +down here the ideality factor is a slope + + align:start position:0% +down here the ideality factor is a slope + + + align:start position:0% +down here the ideality factor is a slope +Factor what that means is um here if we + + align:start position:0% +Factor what that means is um here if we + + + align:start position:0% +Factor what that means is um here if we +go back to this if you change your + + align:start position:0% +go back to this if you change your + + + align:start position:0% +go back to this if you change your +ideality Factor you're changing the + + align:start position:0% +ideality Factor you're changing the + + + align:start position:0% +ideality Factor you're changing the +slope in log scale it still be a + + align:start position:0% +slope in log scale it still be a + + + align:start position:0% +slope in log scale it still be a +straight line but if your ideality + + align:start position:0% +straight line but if your ideality + + + align:start position:0% +straight line but if your ideality +Factor increases you would get something + + align:start position:0% +Factor increases you would get something + + + align:start position:0% +Factor increases you would get something +like this if it decreases the slope + + align:start position:0% +like this if it decreases the slope + + + align:start position:0% +like this if it decreases the slope +would uh increase right because you have + + align:start position:0% +would uh increase right because you have + + + align:start position:0% +would uh increase right because you have +the equation dependent on one over uh + + align:start position:0% +the equation dependent on one over uh + + + align:start position:0% +the equation dependent on one over uh +this parameter okay so um the ideality + + align:start position:0% +this parameter okay so um the ideality + + + align:start position:0% +this parameter okay so um the ideality +factor is important as well because it + + align:start position:0% +factor is important as well because it + + + align:start position:0% +factor is important as well because it +indicates the type of recombination + + align:start position:0% +indicates the type of recombination + + + align:start position:0% +indicates the type of recombination +mechanism that's driving the current + + align:start position:0% +mechanism that's driving the current + + + align:start position:0% +mechanism that's driving the current +inside of that region of the device and + + align:start position:0% +inside of that region of the device and + + + align:start position:0% +inside of that region of the device and +if anybody ever comes across this in + + align:start position:0% +if anybody ever comes across this in + + + align:start position:0% +if anybody ever comes across this in +their research come talk to me I'd be + + align:start position:0% +their research come talk to me I'd be + + + align:start position:0% +their research come talk to me I'd be +happy to uh to point you in the right + + align:start position:0% +happy to uh to point you in the right + + + align:start position:0% +happy to uh to point you in the right +directions or you could look up the + + align:start position:0% +directions or you could look up the + + + align:start position:0% +directions or you could look up the +thesis of Keith Macintosh from + + align:start position:0% +thesis of Keith Macintosh from + + + align:start position:0% +thesis of Keith Macintosh from +University of New South Wales um + + align:start position:0% +University of New South Wales um + + + align:start position:0% +University of New South Wales um +excellent excellent thesis entitled + + align:start position:0% +excellent excellent thesis entitled + + + align:start position:0% +excellent excellent thesis entitled +humps lumps and bumps um a + + align:start position:0% +humps lumps and bumps um a + + + align:start position:0% +humps lumps and bumps um a +threedimensional threedimensional + + align:start position:0% +threedimensional threedimensional + + + align:start position:0% +threedimensional threedimensional +effects of the current voltage curve of + + align:start position:0% +effects of the current voltage curve of + + + align:start position:0% +effects of the current voltage curve of +silicon solar cells some of which might + + align:start position:0% +silicon solar cells some of which might + + + align:start position:0% +silicon solar cells some of which might +apply as well to other material systems + + align:start position:0% +apply as well to other material systems + + + align:start position:0% +apply as well to other material systems +as well and you can tell where the lumps + + align:start position:0% +as well and you can tell where the lumps + + + align:start position:0% +as well and you can tell where the lumps +humps and bumps comes from it's really + + align:start position:0% +humps and bumps comes from it's really + + + align:start position:0% +humps and bumps comes from it's really +these uh lumps humps and bumps in the IV + + align:start position:0% +these uh lumps humps and bumps in the IV + + + align:start position:0% +these uh lumps humps and bumps in the IV +curve that he's talking about excellent + + align:start position:0% +curve that he's talking about excellent + + + align:start position:0% +curve that he's talking about excellent +read very good thesis um highly + + align:start position:0% +read very good thesis um highly + + + align:start position:0% +read very good thesis um highly +recommended for those who want to look + + align:start position:0% +recommended for those who want to look + + + align:start position:0% +recommended for those who want to look +into their IV curves a little bit more + + align:start position:0% +into their IV curves a little bit more + + + align:start position:0% +into their IV curves a little bit more +it's kind of like looking into the tea + + align:start position:0% +it's kind of like looking into the tea + + + align:start position:0% +it's kind of like looking into the tea +leaves right because there are a number + + align:start position:0% +leaves right because there are a number + + + align:start position:0% +leaves right because there are a number +of things that can be affecting the IV + + align:start position:0% +of things that can be affecting the IV + + + align:start position:0% +of things that can be affecting the IV +curves we'll get to some of those uh on + + align:start position:0% +curves we'll get to some of those uh on + + + align:start position:0% +curves we'll get to some of those uh on +on Tuesday as well these are um IV + + align:start position:0% +on Tuesday as well these are um IV + + + align:start position:0% +on Tuesday as well these are um IV +curves again in in in log scale on the + + align:start position:0% +curves again in in in log scale on the + + + align:start position:0% +curves again in in in log scale on the +ordinate linear scale on the abscissa + + align:start position:0% +ordinate linear scale on the abscissa + + + align:start position:0% +ordinate linear scale on the abscissa +you notice there's little commas here + + align:start position:0% +you notice there's little commas here + + + align:start position:0% +you notice there's little commas here +because I took this data in Germany so + + align:start position:0% +because I took this data in Germany so + + + align:start position:0% +because I took this data in Germany so +the decimal place is written as a comma + + align:start position:0% +the decimal place is written as a comma + + + align:start position:0% +the decimal place is written as a comma +uh the um the IV curves uh vary in in in + + align:start position:0% +uh the um the IV curves uh vary in in in + + + align:start position:0% +uh the um the IV curves uh vary in in in +shape and in style let's look at this + + align:start position:0% +shape and in style let's look at this + + + align:start position:0% +shape and in style let's look at this +one right here this black one um it + + align:start position:0% +one right here this black one um it + + + align:start position:0% +one right here this black one um it +starts up like this and then it goes + + align:start position:0% +starts up like this and then it goes + + + align:start position:0% +starts up like this and then it goes +flat for a while and then it becomes + + align:start position:0% +flat for a while and then it becomes + + + align:start position:0% +flat for a while and then it becomes +series it's dominated way up at higher + + align:start position:0% +series it's dominated way up at higher + + + align:start position:0% +series it's dominated way up at higher +bias voltages whereas uh this blue curve + + align:start position:0% +bias voltages whereas uh this blue curve + + + align:start position:0% +bias voltages whereas uh this blue curve +right here this one uh again you have + + align:start position:0% +right here this one uh again you have + + + align:start position:0% +right here this one uh again you have +the effect of shunt resistance at lower + + align:start position:0% +the effect of shunt resistance at lower + + + align:start position:0% +the effect of shunt resistance at lower +bias voltages then you have one diode + + align:start position:0% +bias voltages then you have one diode + + + align:start position:0% +bias voltages then you have one diode +two diodes and eventually the series + + align:start position:0% +two diodes and eventually the series + + + align:start position:0% +two diodes and eventually the series +resistance component coming in as well + + align:start position:0% +resistance component coming in as well + + + align:start position:0% +resistance component coming in as well +or perhaps it's a large shunt as well + + align:start position:0% +or perhaps it's a large shunt as well + + + align:start position:0% +or perhaps it's a large shunt as well +you don't really know until you start + + align:start position:0% +you don't really know until you start + + + align:start position:0% +you don't really know until you start +fitting it and modeling it and maybe + + align:start position:0% +fitting it and modeling it and maybe + + + align:start position:0% +fitting it and modeling it and maybe +measuring the temperature dependence and + + align:start position:0% +measuring the temperature dependence and + + + align:start position:0% +measuring the temperature dependence and +so forth so this gives you a sense of + + align:start position:0% +so forth so this gives you a sense of + + + align:start position:0% +so forth so this gives you a sense of +the the real life uh uh diod IV curves + + align:start position:0% +the the real life uh uh diod IV curves + + + align:start position:0% +the the real life uh uh diod IV curves +that you might get over the course of + + align:start position:0% +that you might get over the course of + + + align:start position:0% +that you might get over the course of +your research and uh gives you some + + align:start position:0% +your research and uh gives you some + + + align:start position:0% +your research and uh gives you some +tools uh to use to begin parsing through + + align:start position:0% +tools uh to use to begin parsing through + + + align:start position:0% +tools uh to use to begin parsing through +and figuring out what's going wrong + + align:start position:0% +and figuring out what's going wrong + + + align:start position:0% +and figuring out what's going wrong +let's talk about that let's talk about + + align:start position:0% +let's talk about that let's talk about + + + align:start position:0% +let's talk about that let's talk about +solving problems so fill Factor what can + + align:start position:0% +solving problems so fill Factor what can + + + align:start position:0% +solving problems so fill Factor what can +impact the fill Factor well we talked + + align:start position:0% +impact the fill Factor well we talked + + + align:start position:0% +impact the fill Factor well we talked +about uh the need for a high fill factor + + align:start position:0% +about uh the need for a high fill factor + + + align:start position:0% +about uh the need for a high fill factor +to produce a high power cell very easy + + align:start position:0% +to produce a high power cell very easy + + + align:start position:0% +to produce a high power cell very easy +to understand the larger the fill Factor + + align:start position:0% +to understand the larger the fill Factor + + + align:start position:0% +to understand the larger the fill Factor +the larger the maximum + + align:start position:0% +the larger the maximum + + + align:start position:0% +the larger the maximum +PowerPoint if you have a low fill Factor + + align:start position:0% +PowerPoint if you have a low fill Factor + + + align:start position:0% +PowerPoint if you have a low fill Factor +your maximum PowerPoint is going to drop + + align:start position:0% +your maximum PowerPoint is going to drop + + + align:start position:0% +your maximum PowerPoint is going to drop +let me show you back and forth Good + + align:start position:0% +let me show you back and forth Good + + + align:start position:0% +let me show you back and forth Good +device bad device large fill Factor low + + align:start position:0% +device bad device large fill Factor low + + + align:start position:0% +device bad device large fill Factor low +fill Factor High maximum power point + + align:start position:0% +fill Factor High maximum power point + + + align:start position:0% +fill Factor High maximum power point +lower maximum power + + align:start position:0% +lower maximum power + + + align:start position:0% +lower maximum power +point okay we talked about this okay so + + align:start position:0% +point okay we talked about this okay so + + + align:start position:0% +point okay we talked about this okay so +causes of shun resistance physical + + align:start position:0% +causes of shun resistance physical + + + align:start position:0% +causes of shun resistance physical +causes I alluded to this earlier but + + align:start position:0% +causes I alluded to this earlier but + + + align:start position:0% +causes I alluded to this earlier but +let's imagine you have that weak spot in + + align:start position:0% +let's imagine you have that weak spot in + + + align:start position:0% +let's imagine you have that weak spot in +your P injunction this is meant to + + align:start position:0% +your P injunction this is meant to + + + align:start position:0% +your P injunction this is meant to +represent the P Junction in two + + align:start position:0% +represent the P Junction in two + + + align:start position:0% +represent the P Junction in two +Dimensions now right so so far we've + + align:start position:0% +Dimensions now right so so far we've + + + align:start position:0% +Dimensions now right so so far we've +only taken a cross-section like this now + + align:start position:0% +only taken a cross-section like this now + + + align:start position:0% +only taken a cross-section like this now +you have a real device in 2D and what + + align:start position:0% +you have a real device in 2D and what + + + align:start position:0% +you have a real device in 2D and what +this is meant to represent is some local + + align:start position:0% +this is meant to represent is some local + + + align:start position:0% +this is meant to represent is some local +weakness in the P Junction and the + + align:start position:0% +weakness in the P Junction and the + + + align:start position:0% +weakness in the P Junction and the +current is now flowing through that + + align:start position:0% +current is now flowing through that + + + align:start position:0% +current is now flowing through that +local weakness weakness so that's uh a + + align:start position:0% +local weakness weakness so that's uh a + + + align:start position:0% +local weakness weakness so that's uh a +representation uh in a in a 2d energy + + align:start position:0% +representation uh in a in a 2d energy + + + align:start position:0% +representation uh in a in a 2d energy +band diagram E versus X versus y right + + align:start position:0% +band diagram E versus X versus y right + + + align:start position:0% +band diagram E versus X versus y right +of uh of of a shunt in realistic + + align:start position:0% +of uh of of a shunt in realistic + + + align:start position:0% +of uh of of a shunt in realistic +conditions so uh shunt uh series + + align:start position:0% +conditions so uh shunt uh series + + + align:start position:0% +conditions so uh shunt uh series +resistance on the other uh hand we we + + align:start position:0% +resistance on the other uh hand we we + + + align:start position:0% +resistance on the other uh hand we we +talked about the effect of High series + + align:start position:0% +talked about the effect of High series + + + align:start position:0% +talked about the effect of High series +resistance and we're going to calculate + + align:start position:0% +resistance and we're going to calculate + + + align:start position:0% +resistance and we're going to calculate +the series resistance for a solar cell + + align:start position:0% +the series resistance for a solar cell + + + align:start position:0% +the series resistance for a solar cell +in part because this is asked for you on + + align:start position:0% +in part because this is asked for you on + + + align:start position:0% +in part because this is asked for you on +your homework assignment at least The + + align:start position:0% +your homework assignment at least The + + + align:start position:0% +your homework assignment at least The +Graduate students have a problem uh + + align:start position:0% +Graduate students have a problem uh + + + align:start position:0% +Graduate students have a problem uh +pertaining to this so let's talk about + + align:start position:0% +pertaining to this so let's talk about + + + align:start position:0% +pertaining to this so let's talk about +the different uh components of series + + align:start position:0% +the different uh components of series + + + align:start position:0% +the different uh components of series +resistance we have a bulk current and an + + align:start position:0% +resistance we have a bulk current and an + + + align:start position:0% +resistance we have a bulk current and an +lateral current inside of a typical + + align:start position:0% +lateral current inside of a typical + + + align:start position:0% +lateral current inside of a typical +solar cell device so sunlight comes in + + align:start position:0% +solar cell device so sunlight comes in + + + align:start position:0% +solar cell device so sunlight comes in +shines generates electron whole pairs + + align:start position:0% +shines generates electron whole pairs + + + align:start position:0% +shines generates electron whole pairs +these electrons will diffuse to the the + + align:start position:0% +these electrons will diffuse to the the + + + align:start position:0% +these electrons will diffuse to the the +the the junction region and then they'll + + align:start position:0% +the the junction region and then they'll + + + align:start position:0% +the the junction region and then they'll +drift Across The Junction wind up in in + + align:start position:0% +drift Across The Junction wind up in in + + + align:start position:0% +drift Across The Junction wind up in in +the submitter uh front surface region + + align:start position:0% +the submitter uh front surface region + + + align:start position:0% +the submitter uh front surface region +and eventually through lateral uh uh + + align:start position:0% +and eventually through lateral uh uh + + + align:start position:0% +and eventually through lateral uh uh +diffusion reach the contacts and be + + align:start position:0% +diffusion reach the contacts and be + + + align:start position:0% +diffusion reach the contacts and be +pulled out of the device so uh we have + + align:start position:0% +pulled out of the device so uh we have + + + align:start position:0% +pulled out of the device so uh we have +to consider these two different + + align:start position:0% +to consider these two different + + + align:start position:0% +to consider these two different +components uh and pretty much the + + align:start position:0% +components uh and pretty much the + + + align:start position:0% +components uh and pretty much the +current all the way from the back + + align:start position:0% +current all the way from the back + + + align:start position:0% +current all the way from the back +contact to the front contact any one of + + align:start position:0% +contact to the front contact any one of + + + align:start position:0% +contact to the front contact any one of +those things could contribute to series + + align:start position:0% +those things could contribute to series + + + align:start position:0% +those things could contribute to series +resistance in an additive sense so to + + align:start position:0% +resistance in an additive sense so to + + + align:start position:0% +resistance in an additive sense so to +put that pictorially we have bulk + + align:start position:0% +put that pictorially we have bulk + + + align:start position:0% +put that pictorially we have bulk +resistance AIT sheet resistance the + + align:start position:0% +resistance AIT sheet resistance the + + + align:start position:0% +resistance AIT sheet resistance the +contact resistance and then line losses + + align:start position:0% +contact resistance and then line losses + + + align:start position:0% +contact resistance and then line losses +uh out of plane as we travel along those + + align:start position:0% +uh out of plane as we travel along those + + + align:start position:0% +uh out of plane as we travel along those +uh front contact + + align:start position:0% +uh front contact + + + align:start position:0% +uh front contact +metalization so bulk resistance this is + + align:start position:0% +metalization so bulk resistance this is + + + align:start position:0% +metalization so bulk resistance this is +another way to State how to choose an + + align:start position:0% +another way to State how to choose an + + + align:start position:0% +another way to State how to choose an +absorber thickness so we've talked about + + align:start position:0% +absorber thickness so we've talked about + + + align:start position:0% +absorber thickness so we've talked about +choosing absorber thicknesses in other + + align:start position:0% +choosing absorber thicknesses in other + + + align:start position:0% +choosing absorber thicknesses in other +words we've talked about choosing the + + align:start position:0% +words we've talked about choosing the + + + align:start position:0% +words we've talked about choosing the +thickness of our solar cell device based + + align:start position:0% +thickness of our solar cell device based + + + align:start position:0% +thickness of our solar cell device based +on how much light we want to capture + + align:start position:0% +on how much light we want to capture + + + align:start position:0% +on how much light we want to capture +based on the optical absorption + + align:start position:0% +based on the optical absorption + + + align:start position:0% +based on the optical absorption +coefficients well guess what this is a + + align:start position:0% +coefficients well guess what this is a + + + align:start position:0% +coefficients well guess what this is a +co-optimization problem we also have to + + align:start position:0% +co-optimization problem we also have to + + + align:start position:0% +co-optimization problem we also have to +worry about the finite resistance of the + + align:start position:0% +worry about the finite resistance of the + + + align:start position:0% +worry about the finite resistance of the +bulk material and we have to spec the + + align:start position:0% +bulk material and we have to spec the + + + align:start position:0% +bulk material and we have to spec the +thickness accordingly so that we don't + + align:start position:0% +thickness accordingly so that we don't + + + align:start position:0% +thickness accordingly so that we don't +wind up with too thick of a bulk + + align:start position:0% +wind up with too thick of a bulk + + + align:start position:0% +wind up with too thick of a bulk +material and the series resistance + + align:start position:0% +material and the series resistance + + + align:start position:0% +material and the series resistance +component will be too large so how to + + align:start position:0% +component will be too large so how to + + + align:start position:0% +component will be too large so how to +choose the appropriate absorber + + align:start position:0% +choose the appropriate absorber + + + align:start position:0% +choose the appropriate absorber +thickness let's talk about that for a + + align:start position:0% +thickness let's talk about that for a + + + align:start position:0% +thickness let's talk about that for a +minute so you can measure a parameter in + + align:start position:0% +minute so you can measure a parameter in + + + align:start position:0% +minute so you can measure a parameter in +the bulk called + + align:start position:0% +the bulk called + + + align:start position:0% +the bulk called +resistivity resistivity will be given as + + align:start position:0% +resistivity resistivity will be given as + + + align:start position:0% +resistivity resistivity will be given as +a function of of Q which is the charge + + align:start position:0% +a function of of Q which is the charge + + + align:start position:0% +a function of of Q which is the charge +mu which is the carrier Mobility which + + align:start position:0% +mu which is the carrier Mobility which + + + align:start position:0% +mu which is the carrier Mobility which +means how easy is it for that carrier to + + align:start position:0% +means how easy is it for that carrier to + + + align:start position:0% +means how easy is it for that carrier to +move around the lce and N being the + + align:start position:0% +move around the lce and N being the + + + align:start position:0% +move around the lce and N being the +carrier density so let's think that + + align:start position:0% +carrier density so let's think that + + + align:start position:0% +carrier density so let's think that +through resistivity if our carrier + + align:start position:0% +through resistivity if our carrier + + + align:start position:0% +through resistivity if our carrier +density goes up if we have more carriers + + align:start position:0% +density goes up if we have more carriers + + + align:start position:0% +density goes up if we have more carriers +to transport the charge the resistivity + + align:start position:0% +to transport the charge the resistivity + + + align:start position:0% +to transport the charge the resistivity +should go down that makes sense check if + + align:start position:0% +should go down that makes sense check if + + + align:start position:0% +should go down that makes sense check if +the mobility goes up meaning it's easier + + align:start position:0% +the mobility goes up meaning it's easier + + + align:start position:0% +the mobility goes up meaning it's easier +for the carriers to move around the + + align:start position:0% +for the carriers to move around the + + + align:start position:0% +for the carriers to move around the +lattice then the resistivity should go + + align:start position:0% +lattice then the resistivity should go + + + align:start position:0% +lattice then the resistivity should go +down check okay so that makes good + + align:start position:0% +down check okay so that makes good + + + align:start position:0% +down check okay so that makes good +intuitive sense now the base resistance + + align:start position:0% +intuitive sense now the base resistance + + + align:start position:0% +intuitive sense now the base resistance +in other words the resistance that we + + align:start position:0% +in other words the resistance that we + + + align:start position:0% +in other words the resistance that we +should have as current travels across + + align:start position:0% +should have as current travels across + + + align:start position:0% +should have as current travels across +the base across the the absorber of our + + align:start position:0% +the base across the the absorber of our + + + align:start position:0% +the base across the the absorber of our +material which we also call the base of + + align:start position:0% +material which we also call the base of + + + align:start position:0% +material which we also call the base of +our solar cell so as the total + + align:start position:0% +our solar cell so as the total + + + align:start position:0% +our solar cell so as the total +resistance as current goes across the + + align:start position:0% +resistance as current goes across the + + + align:start position:0% +resistance as current goes across the +base should be given as row which is a + + align:start position:0% +base should be given as row which is a + + + align:start position:0% +base should be given as row which is a +fundamental material + + align:start position:0% +fundamental material + + + align:start position:0% +fundamental material +parameter combined with some geometric + + align:start position:0% +parameter combined with some geometric + + + align:start position:0% +parameter combined with some geometric +parameters that Define the size of our + + align:start position:0% +parameters that Define the size of our + + + align:start position:0% +parameters that Define the size of our +solar cell so L is going to be the + + align:start position:0% +solar cell so L is going to be the + + + align:start position:0% +solar cell so L is going to be the +length of the conductive path which + + align:start position:0% +length of the conductive path which + + + align:start position:0% +length of the conductive path which +typically would be given as the + + align:start position:0% +typically would be given as the + + + align:start position:0% +typically would be given as the +thickness of the device and a is the + + align:start position:0% +thickness of the device and a is the + + + align:start position:0% +thickness of the device and a is the +area of current flow in other words the + + align:start position:0% +area of current flow in other words the + + + align:start position:0% +area of current flow in other words the +Dimension or size of our solar cell + + align:start position:0% +Dimension or size of our solar cell + + + align:start position:0% +Dimension or size of our solar cell +device so to minimize base resistance we + + align:start position:0% +device so to minimize base resistance we + + + align:start position:0% +device so to minimize base resistance we +want to have a very thin solar cell + + align:start position:0% +want to have a very thin solar cell + + + align:start position:0% +want to have a very thin solar cell +device but wait a second if we make it + + align:start position:0% +device but wait a second if we make it + + + align:start position:0% +device but wait a second if we make it +very thin then what + + align:start position:0% +very thin then what + + + align:start position:0% +very thin then what +happens a less absorption so we have to + + align:start position:0% +happens a less absorption so we have to + + + align:start position:0% +happens a less absorption so we have to +make it a certain thickness to get a + + align:start position:0% +make it a certain thickness to get a + + + align:start position:0% +make it a certain thickness to get a +good enough absorption then we can + + align:start position:0% +good enough absorption then we can + + + align:start position:0% +good enough absorption then we can +compensate if we still need to drop the + + align:start position:0% +compensate if we still need to drop the + + + align:start position:0% +compensate if we still need to drop the +base resistance we can increase the area + + align:start position:0% +base resistance we can increase the area + + + align:start position:0% +base resistance we can increase the area +of the base right and so far um that + + align:start position:0% +of the base right and so far um that + + + align:start position:0% +of the base right and so far um that +makes good sense there's nothing else uh + + align:start position:0% +makes good sense there's nothing else uh + + + align:start position:0% +makes good sense there's nothing else uh +tugging uh for the area to be in the the + + align:start position:0% +tugging uh for the area to be in the the + + + align:start position:0% +tugging uh for the area to be in the the +other direction right so we can make + + align:start position:0% +other direction right so we can make + + + align:start position:0% +other direction right so we can make +this solar cell infinitely large um + + align:start position:0% +this solar cell infinitely large um + + + align:start position:0% +this solar cell infinitely large um +thick as we want it to be to absorb all + + align:start position:0% +thick as we want it to be to absorb all + + + align:start position:0% +thick as we want it to be to absorb all +the light great okay hold on to that + + align:start position:0% +the light great okay hold on to that + + + align:start position:0% +the light great okay hold on to that +thought because we're going to have + + align:start position:0% +thought because we're going to have + + + align:start position:0% +thought because we're going to have +another constraining parameter that + + align:start position:0% +another constraining parameter that + + + align:start position:0% +another constraining parameter that +pushes Us in the opposite way in a few + + align:start position:0% +pushes Us in the opposite way in a few + + + align:start position:0% +pushes Us in the opposite way in a few +slides all right so the emitter sheet + + align:start position:0% +slides all right so the emitter sheet + + + align:start position:0% +slides all right so the emitter sheet +resistance um in other words how to + + align:start position:0% +resistance um in other words how to + + + align:start position:0% +resistance um in other words how to +design front contact metalization + + align:start position:0% +design front contact metalization + + + align:start position:0% +design front contact metalization +emitter sheet resistance refers to the + + align:start position:0% +emitter sheet resistance refers to the + + + align:start position:0% +emitter sheet resistance refers to the +resistance of lateral current that the + + align:start position:0% +resistance of lateral current that the + + + align:start position:0% +resistance of lateral current that the +carriers will experience as they move + + align:start position:0% +carriers will experience as they move + + + align:start position:0% +carriers will experience as they move +laterally to reach the front contacts + + align:start position:0% +laterally to reach the front contacts + + + align:start position:0% +laterally to reach the front contacts +and again we go back to this fundamental + + align:start position:0% +and again we go back to this fundamental + + + align:start position:0% +and again we go back to this fundamental +material parameter uh where we have uh + + align:start position:0% +material parameter uh where we have uh + + + align:start position:0% +material parameter uh where we have uh +resistivity as a function of mobility + + align:start position:0% +resistivity as a function of mobility + + + align:start position:0% +resistivity as a function of mobility +and total dopent concentration sorry for + + align:start position:0% +and total dopent concentration sorry for + + + align:start position:0% +and total dopent concentration sorry for +some reason I used the big n here in a + + align:start position:0% +some reason I used the big n here in a + + + align:start position:0% +some reason I used the big n here in a +little end on the previous slide but + + align:start position:0% +little end on the previous slide but + + + align:start position:0% +little end on the previous slide but +it's the same thing it's carrier density + + align:start position:0% +it's the same thing it's carrier density + + + align:start position:0% +it's the same thing it's carrier density +so again our resistivity is a function + + align:start position:0% +so again our resistivity is a function + + + align:start position:0% +so again our resistivity is a function +of carrier mobility and carrier + + align:start position:0% +of carrier mobility and carrier + + + align:start position:0% +of carrier mobility and carrier +concentration how easy it is for the + + align:start position:0% +concentration how easy it is for the + + + align:start position:0% +concentration how easy it is for the +carriers to move and how many of them + + align:start position:0% +carriers to move and how many of them + + + align:start position:0% +carriers to move and how many of them +are there for a thin layer a sheet + + align:start position:0% +are there for a thin layer a sheet + + + align:start position:0% +are there for a thin layer a sheet +resistance can be described as the + + align:start position:0% +resistance can be described as the + + + align:start position:0% +resistance can be described as the +integral of the resistivity by the + + align:start position:0% +integral of the resistivity by the + + + align:start position:0% +integral of the resistivity by the +thickness of that layer or to put it + + align:start position:0% +thickness of that layer or to put it + + + align:start position:0% +thickness of that layer or to put it +more simply if you have a uniform layer + + align:start position:0% +more simply if you have a uniform layer + + + align:start position:0% +more simply if you have a uniform layer +you simply multiply the the denominator + + align:start position:0% +you simply multiply the the denominator + + + align:start position:0% +you simply multiply the the denominator +here by thickness so this this can be + + align:start position:0% +here by thickness so this this can be + + + align:start position:0% +here by thickness so this this can be +thought of in the following way if we + + align:start position:0% +thought of in the following way if we + + + align:start position:0% +thought of in the following way if we +have a thicker uh emitter thicker + + align:start position:0% +have a thicker uh emitter thicker + + + align:start position:0% +have a thicker uh emitter thicker +emitter right we will be dropping the + + align:start position:0% +emitter right we will be dropping the + + + align:start position:0% +emitter right we will be dropping the +emitter sheet resistance we will be + + align:start position:0% +emitter sheet resistance we will be + + + align:start position:0% +emitter sheet resistance we will be +dropping the uh resistance component uh + + align:start position:0% +dropping the uh resistance component uh + + + align:start position:0% +dropping the uh resistance component uh +that carriers uh experience as they + + align:start position:0% +that carriers uh experience as they + + + align:start position:0% +that carriers uh experience as they +travel laterally through this and that + + align:start position:0% +travel laterally through this and that + + + align:start position:0% +travel laterally through this and that +makes sense because in effect as we + + align:start position:0% +makes sense because in effect as we + + + align:start position:0% +makes sense because in effect as we +increase the thickness of this emitter + + align:start position:0% +increase the thickness of this emitter + + + align:start position:0% +increase the thickness of this emitter +region we're increasing the total + + align:start position:0% +region we're increasing the total + + + align:start position:0% +region we're increasing the total +cross-sectional area for the charges to + + align:start position:0% +cross-sectional area for the charges to + + + align:start position:0% +cross-sectional area for the charges to +travel through right + + align:start position:0% +travel through right + + + align:start position:0% +travel through right +so folks with me so far for the emitter + + align:start position:0% +so folks with me so far for the emitter + + + align:start position:0% +so folks with me so far for the emitter +sheet resistance to be uh low we need + + align:start position:0% +sheet resistance to be uh low we need + + + align:start position:0% +sheet resistance to be uh low we need +the thickness to be good enough uh the + + align:start position:0% +the thickness to be good enough uh the + + + align:start position:0% +the thickness to be good enough uh the +thickness to be thick enough the carrier + + align:start position:0% +thickness to be thick enough the carrier + + + align:start position:0% +thickness to be thick enough the carrier +density to be high enough and the + + align:start position:0% +density to be high enough and the + + + align:start position:0% +density to be high enough and the +mobility to be large enough and often + + align:start position:0% +mobility to be large enough and often + + + align:start position:0% +mobility to be large enough and often +times uh the resistivity of a material + + align:start position:0% +times uh the resistivity of a material + + + align:start position:0% +times uh the resistivity of a material +you might spend months trying to + + align:start position:0% +you might spend months trying to + + + align:start position:0% +you might spend months trying to +optimize the resistivity of your emitter + + align:start position:0% +optimize the resistivity of your emitter + + + align:start position:0% +optimize the resistivity of your emitter +region for those doing thinfilm + + align:start position:0% +region for those doing thinfilm + + + align:start position:0% +region for those doing thinfilm +materials you might be working on zinc + + align:start position:0% +materials you might be working on zinc + + + align:start position:0% +materials you might be working on zinc +oxide uh aluminum doped or Florine doped + + align:start position:0% +oxide uh aluminum doped or Florine doped + + + align:start position:0% +oxide uh aluminum doped or Florine doped +zinc oxide for instance and after months + + align:start position:0% +zinc oxide for instance and after months + + + align:start position:0% +zinc oxide for instance and after months +of tuning the temperature and the oxygen + + align:start position:0% +of tuning the temperature and the oxygen + + + align:start position:0% +of tuning the temperature and the oxygen +partial pressure during the deposition + + align:start position:0% +partial pressure during the deposition + + + align:start position:0% +partial pressure during the deposition +process you're there and you have what + + align:start position:0% +process you're there and you have what + + + align:start position:0% +process you're there and you have what +you have you have a certain carry + + align:start position:0% +you have you have a certain carry + + + align:start position:0% +you have you have a certain carry +density and a certain mobility and you + + align:start position:0% +density and a certain mobility and you + + + align:start position:0% +density and a certain mobility and you +can't do much more than vary the + + align:start position:0% +can't do much more than vary the + + + align:start position:0% +can't do much more than vary the +geometric parameter varying the + + align:start position:0% +geometric parameter varying the + + + align:start position:0% +geometric parameter varying the +thickness so what next if my thickness + + align:start position:0% +thickness so what next if my thickness + + + align:start position:0% +thickness so what next if my thickness +is too big on my emitter if my thickness + + align:start position:0% +is too big on my emitter if my thickness + + + align:start position:0% +is too big on my emitter if my thickness +is too big I'm going to be absorbing all + + align:start position:0% +is too big I'm going to be absorbing all + + + align:start position:0% +is too big I'm going to be absorbing all +of my short wavelength photons in the + + align:start position:0% +of my short wavelength photons in the + + + align:start position:0% +of my short wavelength photons in the +front surface of my + + align:start position:0% +front surface of my + + + align:start position:0% +front surface of my +device and maybe the current collection + + align:start position:0% +device and maybe the current collection + + + align:start position:0% +device and maybe the current collection +probability from that layer up here that + + align:start position:0% +probability from that layer up here that + + + align:start position:0% +probability from that layer up here that +has a very high uh uh uh uh uh carrier + + align:start position:0% +has a very high uh uh uh uh uh carrier + + + align:start position:0% +has a very high uh uh uh uh uh carrier +density is not going to be as large in + + align:start position:0% +density is not going to be as large in + + + align:start position:0% +density is not going to be as large in +other words the current collection + + align:start position:0% +other words the current collection + + + align:start position:0% +other words the current collection +efficiency won't be as large as if I + + align:start position:0% +efficiency won't be as large as if I + + + align:start position:0% +efficiency won't be as large as if I +generated the carriers here in the bulk + + align:start position:0% +generated the carriers here in the bulk + + + align:start position:0% +generated the carriers here in the bulk +because of an effect called a Rec + + align:start position:0% +because of an effect called a Rec + + + align:start position:0% +because of an effect called a Rec +combination which we get to in a few + + align:start position:0% +combination which we get to in a few + + + align:start position:0% +combination which we get to in a few +lectures so this uh front surface region + + align:start position:0% +lectures so this uh front surface region + + + align:start position:0% +lectures so this uh front surface region +here often times is considered a dead + + align:start position:0% +here often times is considered a dead + + + align:start position:0% +here often times is considered a dead +layer to a solar cell its electrical + + align:start position:0% +layer to a solar cell its electrical + + + align:start position:0% +layer to a solar cell its electrical +properties are very very poor so if I + + align:start position:0% +properties are very very poor so if I + + + align:start position:0% +properties are very very poor so if I +make this layer too thick sure I get rid + + align:start position:0% +make this layer too thick sure I get rid + + + align:start position:0% +make this layer too thick sure I get rid +of my emitter sheet resistance term but + + align:start position:0% +of my emitter sheet resistance term but + + + align:start position:0% +of my emitter sheet resistance term but +at the same time I'm killing my Quantum + + align:start position:0% +at the same time I'm killing my Quantum + + + align:start position:0% +at the same time I'm killing my Quantum +efficiency in the short + + align:start position:0% +efficiency in the short + + + align:start position:0% +efficiency in the short +wavelengths because I'm not able to + + align:start position:0% +wavelengths because I'm not able to + + + align:start position:0% +wavelengths because I'm not able to +absorb those short wavelength photons + + align:start position:0% +absorb those short wavelength photons + + + align:start position:0% +absorb those short wavelength photons +and convert them efficiency efficiently + + align:start position:0% +and convert them efficiency efficiently + + + align:start position:0% +and convert them efficiency efficiently +into electron hole + + align:start position:0% +into electron hole + + + align:start position:0% +into electron hole +pairs so this is a story about + + align:start position:0% +pairs so this is a story about + + + align:start position:0% +pairs so this is a story about +co-optimization of different device + + align:start position:0% +co-optimization of different device + + + align:start position:0% +co-optimization of different device +parameters so let's let's keep this + + align:start position:0% +parameters so let's let's keep this + + + align:start position:0% +parameters so let's let's keep this +thought for a minute and let's now try + + align:start position:0% +thought for a minute and let's now try + + + align:start position:0% +thought for a minute and let's now try +to calculate the total power loss due to + + align:start position:0% +to calculate the total power loss due to + + + align:start position:0% +to calculate the total power loss due to +the emitter sheet resistance because now + + align:start position:0% +the emitter sheet resistance because now + + + align:start position:0% +the emitter sheet resistance because now +we have this weird unit of ohms per + + align:start position:0% +we have this weird unit of ohms per + + + align:start position:0% +we have this weird unit of ohms per +square in reality it's ohms but when we + + align:start position:0% +square in reality it's ohms but when we + + + align:start position:0% +square in reality it's ohms but when we +take think about emitter sheet + + align:start position:0% +take think about emitter sheet + + + align:start position:0% +take think about emitter sheet +resistance since we're thinking about a + + align:start position:0% +resistance since we're thinking about a + + + align:start position:0% +resistance since we're thinking about a +square of the material um we have units + + align:start position:0% +square of the material um we have units + + + align:start position:0% +square of the material um we have units +of ohms per square square being a + + align:start position:0% +of ohms per square square being a + + + align:start position:0% +of ohms per square square being a +unitless parameter uh so it has uh let's + + align:start position:0% +unitless parameter uh so it has uh let's + + + align:start position:0% +unitless parameter uh so it has uh let's +see resistivity had units of ohm + + align:start position:0% +see resistivity had units of ohm + + + align:start position:0% +see resistivity had units of ohm +centimeter we divided our resistivity by + + align:start position:0% +centimeter we divided our resistivity by + + + align:start position:0% +centimeter we divided our resistivity by +our thickness of that emitter region so + + align:start position:0% +our thickness of that emitter region so + + + align:start position:0% +our thickness of that emitter region so +our units became ohms and and ohms per + + align:start position:0% +our units became ohms and and ohms per + + + align:start position:0% +our units became ohms and and ohms per +square here is the the units typically + + align:start position:0% +square here is the the units typically + + + align:start position:0% +square here is the the units typically +given for meter sheet resistance and um + + align:start position:0% +given for meter sheet resistance and um + + + align:start position:0% +given for meter sheet resistance and um +and now we have to convert this into + + align:start position:0% +and now we have to convert this into + + + align:start position:0% +and now we have to convert this into +some meaningful parameter uh for actual + + align:start position:0% +some meaningful parameter uh for actual + + + align:start position:0% +some meaningful parameter uh for actual +solar cell device so if you want to + + align:start position:0% +solar cell device so if you want to + + + align:start position:0% +solar cell device so if you want to +calculate the fraction of power lost due + + align:start position:0% +calculate the fraction of power lost due + + + align:start position:0% +calculate the fraction of power lost due +to this emitter sheet resistance it's + + align:start position:0% +to this emitter sheet resistance it's + + + align:start position:0% +to this emitter sheet resistance it's +fairly straightforward we would have to + + align:start position:0% +fairly straightforward we would have to + + + align:start position:0% +fairly straightforward we would have to +think about the current uh since power + + align:start position:0% +think about the current uh since power + + + align:start position:0% +think about the current uh since power +is i^ s r we have to think about the + + align:start position:0% +is i^ s r we have to think about the + + + align:start position:0% +is i^ s r we have to think about the +current as a function of the resistance + + align:start position:0% +current as a function of the resistance + + + align:start position:0% +current as a function of the resistance +right as a function of the position here + + align:start position:0% +right as a function of the position here + + + align:start position:0% +right as a function of the position here +we're integrating over uh y y being uh + + align:start position:0% +we're integrating over uh y y being uh + + + align:start position:0% +we're integrating over uh y y being uh +the lateral Dimension and we're + + align:start position:0% +the lateral Dimension and we're + + + align:start position:0% +the lateral Dimension and we're +integrating imagine the separation + + align:start position:0% +integrating imagine the separation + + + align:start position:0% +integrating imagine the separation +between contacts is s so here's one + + align:start position:0% +between contacts is s so here's one + + + align:start position:0% +between contacts is s so here's one +contact metal finger here's the next + + align:start position:0% +contact metal finger here's the next + + + align:start position:0% +contact metal finger here's the next +contact metal finger it's extracting + + align:start position:0% +contact metal finger it's extracting + + + align:start position:0% +contact metal finger it's extracting +charge from the material and we have a a + + align:start position:0% +charge from the material and we have a a + + + align:start position:0% +charge from the material and we have a a +certain distance s right here between + + align:start position:0% +certain distance s right here between + + + align:start position:0% +certain distance s right here between +them so the maximum distance that the + + align:start position:0% +them so the maximum distance that the + + + align:start position:0% +them so the maximum distance that the +current would travel in principle would + + align:start position:0% +current would travel in principle would + + + align:start position:0% +current would travel in principle would +be S / 2 since any current that reaches + + align:start position:0% +be S / 2 since any current that reaches + + + align:start position:0% +be S / 2 since any current that reaches +the emitter over here will be collected + + align:start position:0% +the emitter over here will be collected + + + align:start position:0% +the emitter over here will be collected +by this contact grid and any electrons + + align:start position:0% +by this contact grid and any electrons + + + align:start position:0% +by this contact grid and any electrons +reaching the emitter over here will be + + align:start position:0% +reaching the emitter over here will be + + + align:start position:0% +reaching the emitter over here will be +collected by that contact grid + + align:start position:0% +collected by that contact grid + + + align:start position:0% +collected by that contact grid +finger okay so now we have our current + + align:start position:0% +finger okay so now we have our current + + + align:start position:0% +finger okay so now we have our current +uh we can translate that into here where + + align:start position:0% +uh we can translate that into here where + + + align:start position:0% +uh we can translate that into here where +we have our b b being the uh vertical + + align:start position:0% +we have our b b being the uh vertical + + + align:start position:0% +we have our b b being the uh vertical +Dimension um y being the horizontal + + align:start position:0% +Dimension um y being the horizontal + + + align:start position:0% +Dimension um y being the horizontal +Dimension here um and we would get uh + + align:start position:0% +Dimension here um and we would get uh + + + align:start position:0% +Dimension here um and we would get uh +this equation coming out right on the + + align:start position:0% +this equation coming out right on the + + + align:start position:0% +this equation coming out right on the +other side which is a function of the + + align:start position:0% +other side which is a function of the + + + align:start position:0% +other side which is a function of the +separation of our contact metalization + + align:start position:0% +separation of our contact metalization + + + align:start position:0% +separation of our contact metalization +fingers to the cube to the third power + + align:start position:0% +fingers to the cube to the third power + + + align:start position:0% +fingers to the cube to the third power +so the power loss coming from the solar + + align:start position:0% +so the power loss coming from the solar + + + align:start position:0% +so the power loss coming from the solar +cell device as we separate our contact + + align:start position:0% +cell device as we separate our contact + + + align:start position:0% +cell device as we separate our contact +metalization by a small amount this + + align:start position:0% +metalization by a small amount this + + + align:start position:0% +metalization by a small amount this +power loss is going to go up very + + align:start position:0% +power loss is going to go up very + + + align:start position:0% +power loss is going to go up very +quickly that's a really deep point to to + + align:start position:0% +quickly that's a really deep point to to + + + align:start position:0% +quickly that's a really deep point to to +to recognize here because what this + + align:start position:0% +to recognize here because what this + + + align:start position:0% +to recognize here because what this +means in effect is that we can lose a + + align:start position:0% +means in effect is that we can lose a + + + align:start position:0% +means in effect is that we can lose a +lot of power very quickly in our solar + + align:start position:0% +lot of power very quickly in our solar + + + align:start position:0% +lot of power very quickly in our solar +cell device if we place our contact + + align:start position:0% +cell device if we place our contact + + + align:start position:0% +cell device if we place our contact +fingers too far apart due to this + + align:start position:0% +fingers too far apart due to this + + + align:start position:0% +fingers too far apart due to this +emitter sheet resistance effect due to + + align:start position:0% +emitter sheet resistance effect due to + + + align:start position:0% +emitter sheet resistance effect due to +the row Subs which is our emitter sheet + + align:start position:0% +the row Subs which is our emitter sheet + + + align:start position:0% +the row Subs which is our emitter sheet +resistance or emitter sheet resistance + + align:start position:0% +resistance or emitter sheet resistance + + + align:start position:0% +resistance or emitter sheet resistance +right here okay so then if we uh divide + + align:start position:0% +right here okay so then if we uh divide + + + align:start position:0% +right here okay so then if we uh divide +the power loss by the maximum power + + align:start position:0% +the power loss by the maximum power + + + align:start position:0% +the power loss by the maximum power +point we essentially get a normalized + + align:start position:0% +point we essentially get a normalized + + + align:start position:0% +point we essentially get a normalized +power loss um and so if you want to say + + align:start position:0% +power loss um and so if you want to say + + + align:start position:0% +power loss um and so if you want to say +limit this ratio to a certain fraction + + align:start position:0% +limit this ratio to a certain fraction + + + align:start position:0% +limit this ratio to a certain fraction +say 4% of total power is lost due to M + + align:start position:0% +say 4% of total power is lost due to M + + + align:start position:0% +say 4% of total power is lost due to M +sheet resistance now we can Define the + + align:start position:0% +sheet resistance now we can Define the + + + align:start position:0% +sheet resistance now we can Define the +geometric parameter the distance between + + align:start position:0% +geometric parameter the distance between + + + align:start position:0% +geometric parameter the distance between +the contact metal that we need to do to + + align:start position:0% +the contact metal that we need to do to + + + align:start position:0% +the contact metal that we need to do to +do in an actual solar cell and if you + + align:start position:0% +do in an actual solar cell and if you + + + align:start position:0% +do in an actual solar cell and if you +run through the + + align:start position:0% +run through the + + + align:start position:0% +run through the +calculations uh with a typical uh set of + + align:start position:0% +calculations uh with a typical uh set of + + + align:start position:0% +calculations uh with a typical uh set of +parameters for a silicon based solar + + align:start position:0% +parameters for a silicon based solar + + + align:start position:0% +parameters for a silicon based solar +cell you'll find up find out that your + + align:start position:0% +cell you'll find up find out that your + + + align:start position:0% +cell you'll find up find out that your +uh uh metalization finger should be + + align:start position:0% +uh uh metalization finger should be + + + align:start position:0% +uh uh metalization finger should be +separated on the order of 4 mm and if + + align:start position:0% +separated on the order of 4 mm and if + + + align:start position:0% +separated on the order of 4 mm and if +you remember the real solar cell devices + + align:start position:0% +you remember the real solar cell devices + + + align:start position:0% +you remember the real solar cell devices +that you saw embedded in that module the + + align:start position:0% +that you saw embedded in that module the + + + align:start position:0% +that you saw embedded in that module the +separation of the fingers is just about + + align:start position:0% +separation of the fingers is just about + + + align:start position:0% +separation of the fingers is just about +4 millim so this is where that finger + + align:start position:0% +4 millim so this is where that finger + + + align:start position:0% +4 millim so this is where that finger +separation comes from in one case you'd + + align:start position:0% +separation comes from in one case you'd + + + align:start position:0% +separation comes from in one case you'd +want to have your fingers spaced really + + align:start position:0% +want to have your fingers spaced really + + + align:start position:0% +want to have your fingers spaced really +really close together to minimize the + + align:start position:0% +really close together to minimize the + + + align:start position:0% +really close together to minimize the +emitter sheet resistance but on the + + align:start position:0% +emitter sheet resistance but on the + + + align:start position:0% +emitter sheet resistance but on the +other hand if you place your fingers too + + align:start position:0% +other hand if you place your fingers too + + + align:start position:0% +other hand if you place your fingers too +close together you're shading the front + + align:start position:0% +close together you're shading the front + + + align:start position:0% +close together you're shading the front +surface of your solar cell with metal + + align:start position:0% +surface of your solar cell with metal + + + align:start position:0% +surface of your solar cell with metal +and light's not going to get in to + + align:start position:0% +and light's not going to get in to + + + align:start position:0% +and light's not going to get in to +generate electron hole pairs so that's + + align:start position:0% +generate electron hole pairs so that's + + + align:start position:0% +generate electron hole pairs so that's +the optimization function that's run + + align:start position:0% +the optimization function that's run + + + align:start position:0% +the optimization function that's run +right there wow so far we I'm counting + + align:start position:0% +right there wow so far we I'm counting + + + align:start position:0% +right there wow so far we I'm counting +three or four of these different + + align:start position:0% +three or four of these different + + + align:start position:0% +three or four of these different +parameters tugging in different + + align:start position:0% +parameters tugging in different + + + align:start position:0% +parameters tugging in different +directions right so you can begin to + + align:start position:0% +directions right so you can begin to + + + align:start position:0% +directions right so you can begin to +sense how constrained the solar cell + + align:start position:0% +sense how constrained the solar cell + + + align:start position:0% +sense how constrained the solar cell +device is in terms of optimization of + + align:start position:0% +device is in terms of optimization of + + + align:start position:0% +device is in terms of optimization of +all these parameters and how easy it is + + align:start position:0% +all these parameters and how easy it is + + + align:start position:0% +all these parameters and how easy it is +to make a very low efficiency device as + + align:start position:0% +to make a very low efficiency device as + + + align:start position:0% +to make a very low efficiency device as +a result how difficult it is to make a + + align:start position:0% +a result how difficult it is to make a + + + align:start position:0% +a result how difficult it is to make a +high efficiency device so um this is + + align:start position:0% +high efficiency device so um this is + + + align:start position:0% +high efficiency device so um this is +interesting um so we have now the + + align:start position:0% +interesting um so we have now the + + + align:start position:0% +interesting um so we have now the +spacing the appropriate spacing between + + align:start position:0% +spacing the appropriate spacing between + + + align:start position:0% +spacing the appropriate spacing between +uh uh fingers it's about 4 mm which + + align:start position:0% +uh uh fingers it's about 4 mm which + + + align:start position:0% +uh uh fingers it's about 4 mm which +means if we're going to be making a + + align:start position:0% +means if we're going to be making a + + + align:start position:0% +means if we're going to be making a +solar cell device say a thin film solar + + align:start position:0% +solar cell device say a thin film solar + + + align:start position:0% +solar cell device say a thin film solar +cell device on a sheet of glass with + + align:start position:0% +cell device on a sheet of glass with + + + align:start position:0% +cell device on a sheet of glass with +some transparent conducting uh material + + align:start position:0% +some transparent conducting uh material + + + align:start position:0% +some transparent conducting uh material +some transparent conducting oxy now we + + align:start position:0% +some transparent conducting oxy now we + + + align:start position:0% +some transparent conducting oxy now we +have our solar cell device we have their + + align:start position:0% +have our solar cell device we have their + + + align:start position:0% +have our solar cell device we have their +front surface here and we have let's say + + align:start position:0% +front surface here and we have let's say + + + align:start position:0% +front surface here and we have let's say +something else on top um we have to + + align:start position:0% +something else on top um we have to + + + align:start position:0% +something else on top um we have to +limit how wide we make that device + + align:start position:0% +limit how wide we make that device + + + align:start position:0% +limit how wide we make that device +otherwise we could be limited by our uh + + align:start position:0% +otherwise we could be limited by our uh + + + align:start position:0% +otherwise we could be limited by our uh +emitter sheet our sheet resistance in + + align:start position:0% +emitter sheet our sheet resistance in + + + align:start position:0% +emitter sheet our sheet resistance in +say the zinc oxide layer of our device + + align:start position:0% +say the zinc oxide layer of our device + + + align:start position:0% +say the zinc oxide layer of our device +and this is interesting now + + align:start position:0% +and this is interesting now + + + align:start position:0% +and this is interesting now +because uh previously for the bulk + + align:start position:0% +because uh previously for the bulk + + + align:start position:0% +because uh previously for the bulk +resistance let's think back over to our + + align:start position:0% +resistance let's think back over to our + + + align:start position:0% +resistance let's think back over to our +bulk resistance we wanted our area to be + + align:start position:0% +bulk resistance we wanted our area to be + + + align:start position:0% +bulk resistance we wanted our area to be +large because we wanted to minimize the + + align:start position:0% +large because we wanted to minimize the + + + align:start position:0% +large because we wanted to minimize the +bulk resistance now we want the area to + + align:start position:0% +bulk resistance now we want the area to + + + align:start position:0% +bulk resistance now we want the area to +be small so that we minimize our M sheet + + align:start position:0% +be small so that we minimize our M sheet + + + align:start position:0% +be small so that we minimize our M sheet +resistance so you can see how the the + + align:start position:0% +resistance so you can see how the the + + + align:start position:0% +resistance so you can see how the the +the current traveling in two orthogonal + + align:start position:0% +the current traveling in two orthogonal + + + align:start position:0% +the current traveling in two orthogonal +directions inside of our device is + + align:start position:0% +directions inside of our device is + + + align:start position:0% +directions inside of our device is +really causing us problems because we're + + align:start position:0% +really causing us problems because we're + + + align:start position:0% +really causing us problems because we're +having to optimize the same parameter in + + align:start position:0% +having to optimize the same parameter in + + + align:start position:0% +having to optimize the same parameter in +different directions for + + align:start position:0% +different directions for + + + align:start position:0% +different directions for +each It's Tricky uh and I'm providing + + align:start position:0% +each It's Tricky uh and I'm providing + + + align:start position:0% +each It's Tricky uh and I'm providing +you the tools here to be able to sit + + align:start position:0% +you the tools here to be able to sit + + + align:start position:0% +you the tools here to be able to sit +down and calculate out uh what is the + + align:start position:0% +down and calculate out uh what is the + + + align:start position:0% +down and calculate out uh what is the +optimal thickness what is the optimal uh + + align:start position:0% +optimal thickness what is the optimal uh + + + align:start position:0% +optimal thickness what is the optimal uh +thickness of your emitter uh of your + + align:start position:0% +thickness of your emitter uh of your + + + align:start position:0% +thickness of your emitter uh of your +base and what is the optimal lateral + + align:start position:0% +base and what is the optimal lateral + + + align:start position:0% +base and what is the optimal lateral +dimensions of your solar cell device to + + align:start position:0% +dimensions of your solar cell device to + + + align:start position:0% +dimensions of your solar cell device to +simultaneously minimize your bulk + + align:start position:0% +simultaneously minimize your bulk + + + align:start position:0% +simultaneously minimize your bulk +resistance and your emitter uh + + align:start position:0% +resistance and your emitter uh + + + align:start position:0% +resistance and your emitter uh +resistance inside of a device and you + + align:start position:0% +resistance inside of a device and you + + + align:start position:0% +resistance inside of a device and you +can do it all now with equations that I + + align:start position:0% +can do it all now with equations that I + + + align:start position:0% +can do it all now with equations that I +just gave you so it's pretty cool at + + align:start position:0% +just gave you so it's pretty cool at + + + align:start position:0% +just gave you so it's pretty cool at +least the first + + align:start position:0% +least the first + + + align:start position:0% +least the first +order how did you define again yeah + + align:start position:0% +order how did you define again yeah + + + align:start position:0% +order how did you define again yeah +absolutely so B was a lateral a vertical + + align:start position:0% +absolutely so B was a lateral a vertical + + + align:start position:0% +absolutely so B was a lateral a vertical +Dimension B is just given as the + + align:start position:0% +Dimension B is just given as the + + + align:start position:0% +Dimension B is just given as the +distance here + + align:start position:0% +distance here + + + align:start position:0% +distance here +yeah that's that's going across if you + + align:start position:0% +yeah that's that's going across if you + + + align:start position:0% +yeah that's that's going across if you +look down your you're looking down on + + align:start position:0% +look down your you're looking down on + + + align:start position:0% +look down your you're looking down on +your on your solar cell so the p and + + align:start position:0% +your on your solar cell so the p and + + + align:start position:0% +your on your solar cell so the p and +Junction would be planer uh to this view + + align:start position:0% +Junction would be planer uh to this view + + + align:start position:0% +Junction would be planer uh to this view +right here y some to the board + + align:start position:0% +right here y some to the board + + + align:start position:0% +right here y some to the board +yep so bird's eye view on the solar cell + + align:start position:0% + + + + align:start position:0% + +any other + + align:start position:0% +any other + + + align:start position:0% +any other +questions okay so um contact resistance + + align:start position:0% +questions okay so um contact resistance + + + align:start position:0% +questions okay so um contact resistance +this is the next thing that can kill a + + align:start position:0% +this is the next thing that can kill a + + + align:start position:0% +this is the next thing that can kill a +solar cell device uh contact resistance + + align:start position:0% +solar cell device uh contact resistance + + + align:start position:0% +solar cell device uh contact resistance +we want to minimize the contact + + align:start position:0% +we want to minimize the contact + + + align:start position:0% +we want to minimize the contact +resistance but the first step to + + align:start position:0% +resistance but the first step to + + + align:start position:0% +resistance but the first step to +minimizing is to measure to know what + + align:start position:0% +minimizing is to measure to know what + + + align:start position:0% +minimizing is to measure to know what +your contact resistance really is and uh + + align:start position:0% +your contact resistance really is and uh + + + align:start position:0% +your contact resistance really is and uh +one simple way to measure contact + + align:start position:0% +one simple way to measure contact + + + align:start position:0% +one simple way to measure contact +resistance is to take a cross-section of + + align:start position:0% +resistance is to take a cross-section of + + + align:start position:0% +resistance is to take a cross-section of +your solar cell device where you've + + align:start position:0% +your solar cell device where you've + + + align:start position:0% +your solar cell device where you've +deposited say four metal fingers on it + + align:start position:0% +deposited say four metal fingers on it + + + align:start position:0% +deposited say four metal fingers on it +and they're appropriately spaced by how + + align:start position:0% +and they're appropriately spaced by how + + + align:start position:0% +and they're appropriately spaced by how +many millimeters or so um so you have a + + align:start position:0% +many millimeters or so um so you have a + + + align:start position:0% +many millimeters or so um so you have a +certain contact resistance right here uh + + align:start position:0% +certain contact resistance right here uh + + + align:start position:0% +certain contact resistance right here uh +between the uh the metal and your U + + align:start position:0% +between the uh the metal and your U + + + align:start position:0% +between the uh the metal and your U +semiconductor material that's denoted as + + align:start position:0% +semiconductor material that's denoted as + + + align:start position:0% +semiconductor material that's denoted as +R subc and then there's a certain uh + + align:start position:0% +R subc and then there's a certain uh + + + align:start position:0% +R subc and then there's a certain uh +emitter resistance that we just talked + + align:start position:0% +emitter resistance that we just talked + + + align:start position:0% +emitter resistance that we just talked +about R subm right here um and if you + + align:start position:0% +about R subm right here um and if you + + + align:start position:0% +about R subm right here um and if you +were to measure the um the current + + align:start position:0% +were to measure the um the current + + + align:start position:0% +were to measure the um the current +passing through uh here to here or + + align:start position:0% +passing through uh here to here or + + + align:start position:0% +passing through uh here to here or +another way to say it is the resistance + + align:start position:0% +another way to say it is the resistance + + + align:start position:0% +another way to say it is the resistance +for current to pass from this point to + + align:start position:0% +for current to pass from this point to + + + align:start position:0% +for current to pass from this point to +that point you might get um let's say + + align:start position:0% +that point you might get um let's say + + + align:start position:0% +that point you might get um let's say +this data point right here a total + + align:start position:0% +this data point right here a total + + + align:start position:0% +this data point right here a total +resistance value of some value and a + + align:start position:0% +resistance value of some value and a + + + align:start position:0% +resistance value of some value and a +distance between uh the two probes of + + align:start position:0% +distance between uh the two probes of + + + align:start position:0% +distance between uh the two probes of +say one times uh D subf where D subf is + + align:start position:0% +say one times uh D subf where D subf is + + + align:start position:0% +say one times uh D subf where D subf is +the unit distance between two adjacent + + align:start position:0% +the unit distance between two adjacent + + + align:start position:0% +the unit distance between two adjacent +uh contact metalization fingers now if + + align:start position:0% +uh contact metalization fingers now if + + + align:start position:0% +uh contact metalization fingers now if +we measure the resistance between this + + align:start position:0% +we measure the resistance between this + + + align:start position:0% +we measure the resistance between this +point and that point we might wind up + + align:start position:0% +point and that point we might wind up + + + align:start position:0% +point and that point we might wind up +with that data point right here + + align:start position:0% +with that data point right here + + + align:start position:0% +with that data point right here +and if we measure the resistance between + + align:start position:0% +and if we measure the resistance between + + + align:start position:0% +and if we measure the resistance between +this point and that point we already did + + align:start position:0% +this point and that point we already did + + + align:start position:0% +this point and that point we already did +that this point and that point we might + + align:start position:0% +that this point and that point we might + + + align:start position:0% +that this point and that point we might +wind up with that data point right here + + align:start position:0% +wind up with that data point right here + + + align:start position:0% +wind up with that data point right here +and so forth and what's happening well + + align:start position:0% +and so forth and what's happening well + + + align:start position:0% +and so forth and what's happening well +as the current goes into the device it + + align:start position:0% +as the current goes into the device it + + + align:start position:0% +as the current goes into the device it +passes once through the contact + + align:start position:0% +passes once through the contact + + + align:start position:0% +passes once through the contact +resistance a certain n * R sub em n + + align:start position:0% +resistance a certain n * R sub em n + + + align:start position:0% +resistance a certain n * R sub em n +being the number of uh metalization + + align:start position:0% +being the number of uh metalization + + + align:start position:0% +being the number of uh metalization +number of hops the number of times we + + align:start position:0% +number of hops the number of times we + + + align:start position:0% +number of hops the number of times we +travel a distance DF and then it goes + + align:start position:0% +travel a distance DF and then it goes + + + align:start position:0% +travel a distance DF and then it goes +out the other side again traveling + + align:start position:0% +out the other side again traveling + + + align:start position:0% +out the other side again traveling +through uh the contact resistance so the + + align:start position:0% +through uh the contact resistance so the + + + align:start position:0% +through uh the contact resistance so the +slope of this line here should be equal + + align:start position:0% +slope of this line here should be equal + + + align:start position:0% +slope of this line here should be equal +to the emitter + + align:start position:0% +to the emitter + + + align:start position:0% +to the emitter +resistance and the offset The Intercept + + align:start position:0% +resistance and the offset The Intercept + + + align:start position:0% +resistance and the offset The Intercept +at uh x equals 0 here The Intercept + + align:start position:0% +at uh x equals 0 here The Intercept + + + align:start position:0% +at uh x equals 0 here The Intercept +should be two times the contact + + align:start position:0% +should be two times the contact + + + align:start position:0% +should be two times the contact +resistance because in principle that + + align:start position:0% +resistance because in principle that + + + align:start position:0% +resistance because in principle that +would be the equivalent of current going + + align:start position:0% +would be the equivalent of current going + + + align:start position:0% +would be the equivalent of current going +in and going back out through this + + align:start position:0% +in and going back out through this + + + align:start position:0% +in and going back out through this +contact resistance right here through + + align:start position:0% +contact resistance right here through + + + align:start position:0% +contact resistance right here through +the same one not traveling at all + + align:start position:0% +the same one not traveling at all + + + align:start position:0% +the same one not traveling at all +through the emitter obviously since + + align:start position:0% +through the emitter obviously since + + + align:start position:0% +through the emitter obviously since +that's impossible to measure we have to + + align:start position:0% +that's impossible to measure we have to + + + align:start position:0% +that's impossible to measure we have to +determine that through extrapolation + + align:start position:0% +determine that through extrapolation + + + align:start position:0% +determine that through extrapolation +back to the the y- axis so this + + align:start position:0% +back to the the y- axis so this + + + align:start position:0% +back to the the y- axis so this +so-called tlm method the transmission + + align:start position:0% +so-called tlm method the transmission + + + align:start position:0% +so-called tlm method the transmission +line method is a method that is used to + + align:start position:0% +line method is a method that is used to + + + align:start position:0% +line method is a method that is used to +determine the contact resistance of a + + align:start position:0% +determine the contact resistance of a + + + align:start position:0% +determine the contact resistance of a +solar cell device um you could either + + align:start position:0% +solar cell device um you could either + + + align:start position:0% +solar cell device um you could either +perform it linearly in this fashion + + align:start position:0% +perform it linearly in this fashion + + + align:start position:0% +perform it linearly in this fashion +right here or using a circular uh uh + + align:start position:0% +right here or using a circular uh uh + + + align:start position:0% +right here or using a circular uh uh +essentially an array of concentric + + align:start position:0% +essentially an array of concentric + + + align:start position:0% +essentially an array of concentric +circles and the latter method is + + align:start position:0% +circles and the latter method is + + + align:start position:0% +circles and the latter method is +typically preferred uh especially in + + align:start position:0% +typically preferred uh especially in + + + align:start position:0% +typically preferred uh especially in +thin film + + align:start position:0% +thin film + + + align:start position:0% +thin film +devices so this is how you measure the + + align:start position:0% +devices so this is how you measure the + + + align:start position:0% +devices so this is how you measure the +contact resistance um and then there are + + align:start position:0% +contact resistance um and then there are + + + align:start position:0% +contact resistance um and then there are +line losses so what can oh let me back + + align:start position:0% +line losses so what can oh let me back + + + align:start position:0% +line losses so what can oh let me back +up one step what can affect the contact + + align:start position:0% +up one step what can affect the contact + + + align:start position:0% +up one step what can affect the contact +resistance typically what affects + + align:start position:0% +resistance typically what affects + + + align:start position:0% +resistance typically what affects +contact resistance is the uh uh Atomic + + align:start position:0% +contact resistance is the uh uh Atomic + + + align:start position:0% +contact resistance is the uh uh Atomic +interface between your metal and your + + align:start position:0% +interface between your metal and your + + + align:start position:0% +interface between your metal and your +semiconductor whether it's an organic or + + align:start position:0% +semiconductor whether it's an organic or + + + align:start position:0% +semiconductor whether it's an organic or +an inorganic semiconductor bless you so + + align:start position:0% +an inorganic semiconductor bless you so + + + align:start position:0% +an inorganic semiconductor bless you so +the uh the the interface here is what + + align:start position:0% +the uh the the interface here is what + + + align:start position:0% +the uh the the interface here is what +determines uh the contact resistance + + align:start position:0% +determines uh the contact resistance + + + align:start position:0% +determines uh the contact resistance +typically and of course the dopent + + align:start position:0% +typically and of course the dopent + + + align:start position:0% +typically and of course the dopent +density uh within your uh + + align:start position:0% +density uh within your uh + + + align:start position:0% +density uh within your uh +semiconductor so components of the + + align:start position:0% +semiconductor so components of the + + + align:start position:0% +semiconductor so components of the +series resistance and the line losses so + + align:start position:0% +series resistance and the line losses so + + + align:start position:0% +series resistance and the line losses so +line losses are essentially the uh + + align:start position:0% +line losses are essentially the uh + + + align:start position:0% +line losses are essentially the uh +losses + + align:start position:0% +losses + + + align:start position:0% +losses +um in the contact metalization lines out + + align:start position:0% +um in the contact metalization lines out + + + align:start position:0% +um in the contact metalization lines out +of plane uh what can cause uh a + + align:start position:0% +of plane uh what can cause uh a + + + align:start position:0% +of plane uh what can cause uh a +resistance in the contact metalization + + align:start position:0% +resistance in the contact metalization + + + align:start position:0% +resistance in the contact metalization +line well intuitively we know that okay + + align:start position:0% +line well intuitively we know that okay + + + align:start position:0% +line well intuitively we know that okay +if the line is too small if the + + align:start position:0% +if the line is too small if the + + + align:start position:0% +if the line is too small if the +cross-section of that line is too tiny + + align:start position:0% +cross-section of that line is too tiny + + + align:start position:0% +cross-section of that line is too tiny +then there's going to be uh High + + align:start position:0% +then there's going to be uh High + + + align:start position:0% +then there's going to be uh High +Resistance uh to current travel along + + align:start position:0% +Resistance uh to current travel along + + + align:start position:0% +Resistance uh to current travel along +that line and indeed that's the case who + + align:start position:0% +that line and indeed that's the case who + + + align:start position:0% +that line and indeed that's the case who +we have the same exact equation as we + + align:start position:0% +we have the same exact equation as we + + + align:start position:0% +we have the same exact equation as we +had for our base resistance now it's + + align:start position:0% +had for our base resistance now it's + + + align:start position:0% +had for our base resistance now it's +applied to the line because in principle + + align:start position:0% +applied to the line because in principle + + + align:start position:0% +applied to the line because in principle +it's the same thing we have current + + align:start position:0% +it's the same thing we have current + + + align:start position:0% +it's the same thing we have current +traveling through uh in in One Direction + + align:start position:0% +traveling through uh in in One Direction + + + align:start position:0% +traveling through uh in in One Direction +along a a constrained uh um + + align:start position:0% +along a a constrained uh um + + + align:start position:0% +along a a constrained uh um +cross-sectional area a certain distance + + align:start position:0% +cross-sectional area a certain distance + + + align:start position:0% +cross-sectional area a certain distance +a certain length so we have now our + + align:start position:0% +a certain length so we have now our + + + align:start position:0% +a certain length so we have now our +resistivity given by the metal obviously + + align:start position:0% +resistivity given by the metal obviously + + + align:start position:0% +resistivity given by the metal obviously +because now we're talking about the + + align:start position:0% +because now we're talking about the + + + align:start position:0% +because now we're talking about the +metal itself not the semiconductor + + align:start position:0% +metal itself not the semiconductor + + + align:start position:0% +metal itself not the semiconductor +anymore current traveling along the + + align:start position:0% +anymore current traveling along the + + + align:start position:0% +anymore current traveling along the +contact metal so the the row becomes the + + align:start position:0% +contact metal so the the row becomes the + + + align:start position:0% +contact metal so the the row becomes the +resistivity of the metal the a becomes + + align:start position:0% +resistivity of the metal the a becomes + + + align:start position:0% +resistivity of the metal the a becomes +the cross-sectional area of the contact + + align:start position:0% +the cross-sectional area of the contact + + + align:start position:0% +the cross-sectional area of the contact +finger and the L is the length of the + + align:start position:0% +finger and the L is the length of the + + + align:start position:0% +finger and the L is the length of the +conductive path in other words how long + + align:start position:0% +conductive path in other words how long + + + align:start position:0% +conductive path in other words how long +how long does the current have to travel + + align:start position:0% +how long does the current have to travel + + + align:start position:0% +how long does the current have to travel +along that contact metal before it + + align:start position:0% +along that contact metal before it + + + align:start position:0% +along that contact metal before it +reaches a highway a bus bar one of those + + align:start position:0% +reaches a highway a bus bar one of those + + + align:start position:0% +reaches a highway a bus bar one of those +really thick uh strips of metal on our + + align:start position:0% +really thick uh strips of metal on our + + + align:start position:0% +really thick uh strips of metal on our +solar cell device + + align:start position:0% +solar cell device + + + align:start position:0% +solar cell device +um in which case it's Home Free so the r + + align:start position:0% +um in which case it's Home Free so the r + + + align:start position:0% +um in which case it's Home Free so the r +the the the the the row rather the uh + + align:start position:0% +the the the the the row rather the uh + + + align:start position:0% +the the the the the row rather the uh +metal resistivity resistivities of + + align:start position:0% +metal resistivity resistivities of + + + align:start position:0% +metal resistivity resistivities of +several uh uh metals and non-metal + + align:start position:0% +several uh uh metals and non-metal + + + align:start position:0% +several uh uh metals and non-metal +materials are given here um that's + + align:start position:0% +materials are given here um that's + + + align:start position:0% +materials are given here um that's +typically why you see silver contact + + align:start position:0% +typically why you see silver contact + + + align:start position:0% +typically why you see silver contact +metalization used for uh solar cells + + align:start position:0% +metalization used for uh solar cells + + + align:start position:0% +metalization used for uh solar cells +it's because it has a very low + + align:start position:0% +it's because it has a very low + + + align:start position:0% +it's because it has a very low +resistivity which means that the + + align:start position:0% +resistivity which means that the + + + align:start position:0% +resistivity which means that the +resistance line losses will be + + align:start position:0% +resistance line losses will be + + + align:start position:0% +resistance line losses will be +small now what is the problem with + + align:start position:0% +small now what is the problem with + + + align:start position:0% +small now what is the problem with +silver does anybody know what percentage + + align:start position:0% +silver does anybody know what percentage + + + align:start position:0% +silver does anybody know what percentage +of the world's silver right now + + align:start position:0% +of the world's silver right now + + + align:start position:0% +of the world's silver right now +manufactured each year is currently + + align:start position:0% +manufactured each year is currently + + + align:start position:0% +manufactured each year is currently +being used for contact metalization on + + align:start position:0% +being used for contact metalization on + + + align:start position:0% +being used for contact metalization on +solar + + align:start position:0% +solar + + + align:start position:0% +solar +cells take a number guess a little lower + + align:start position:0% +cells take a number guess a little lower + + + align:start position:0% +cells take a number guess a little lower +um but but in that order of magnitude so + + align:start position:0% +um but but in that order of magnitude so + + + align:start position:0% +um but but in that order of magnitude so +he said 30 uh somewhere upwards of 10% + + align:start position:0% +he said 30 uh somewhere upwards of 10% + + + align:start position:0% +he said 30 uh somewhere upwards of 10% +right it be your guess so around 10% um + + align:start position:0% +right it be your guess so around 10% um + + + align:start position:0% +right it be your guess so around 10% um +and of course PV is growing at + + align:start position:0% +and of course PV is growing at + + + align:start position:0% +and of course PV is growing at +accumulative annual growth rates in the + + align:start position:0% +accumulative annual growth rates in the + + + align:start position:0% +accumulative annual growth rates in the +several tens of percents per year so + + align:start position:0% +several tens of percents per year so + + + align:start position:0% +several tens of percents per year so +silver utilization is expected to + + align:start position:0% +silver utilization is expected to + + + align:start position:0% +silver utilization is expected to +continue to increase so either we mine + + align:start position:0% +continue to increase so either we mine + + + align:start position:0% +continue to increase so either we mine +more silver or we mer we we venture to + + align:start position:0% +more silver or we mer we we venture to + + + align:start position:0% +more silver or we mer we we venture to +another contact metal uh material and + + align:start position:0% +another contact metal uh material and + + + align:start position:0% +another contact metal uh material and +that's why you see folks looking at the + + align:start position:0% +that's why you see folks looking at the + + + align:start position:0% +that's why you see folks looking at the +copper nickel which is similar in + + align:start position:0% +copper nickel which is similar in + + + align:start position:0% +copper nickel which is similar in +electronic structure it's one uh element + + align:start position:0% +electronic structure it's one uh element + + + align:start position:0% +electronic structure it's one uh element +to the left of copper on the periodic + + align:start position:0% +to the left of copper on the periodic + + + align:start position:0% +to the left of copper on the periodic +table and and other uh metal + + align:start position:0% +table and and other uh metal + + + align:start position:0% +table and and other uh metal +Alternatives yes yeah where does Nickel + + align:start position:0% +Alternatives yes yeah where does Nickel + + + align:start position:0% +Alternatives yes yeah where does Nickel +fall on this res resistivity chart I + + align:start position:0% +fall on this res resistivity chart I + + + align:start position:0% +fall on this res resistivity chart I +have to give you the exact number but if + + align:start position:0% +have to give you the exact number but if + + + align:start position:0% +have to give you the exact number but if +I were to venture a guess what you're + + align:start position:0% +I were to venture a guess what you're + + + align:start position:0% +I were to venture a guess what you're +noticing over here um are several of the + + align:start position:0% +noticing over here um are several of the + + + align:start position:0% +noticing over here um are several of the +um metals that fall in the noble metal + + align:start position:0% +um metals that fall in the noble metal + + + align:start position:0% +um metals that fall in the noble metal +category uh these are far to the right + + align:start position:0% +category uh these are far to the right + + + align:start position:0% +category uh these are far to the right +on the 3D series uh so if you pict the + + align:start position:0% +on the 3D series uh so if you pict the + + + align:start position:0% +on the 3D series uh so if you pict the +periodic table again far in the 3D + + align:start position:0% +periodic table again far in the 3D + + + align:start position:0% +periodic table again far in the 3D +series you have that Dell uh orbital + + align:start position:0% +series you have that Dell uh orbital + + + align:start position:0% +series you have that Dell uh orbital +completely filled and those outermost + + align:start position:0% +completely filled and those outermost + + + align:start position:0% +completely filled and those outermost +electrons are then screened by all the + + align:start position:0% +electrons are then screened by all the + + + align:start position:0% +electrons are then screened by all the +other electrons in the system and very + + align:start position:0% +other electrons in the system and very + + + align:start position:0% +other electrons in the system and very +Loosely bound so you can remove the + + align:start position:0% +Loosely bound so you can remove the + + + align:start position:0% +Loosely bound so you can remove the +electrons fairly easily um it's one of + + align:start position:0% +electrons fairly easily um it's one of + + + align:start position:0% +electrons fairly easily um it's one of +the reasons why these uh these these + + align:start position:0% +the reasons why these uh these these + + + align:start position:0% +the reasons why these uh these these +elements in that class have a higher + + align:start position:0% +elements in that class have a higher + + + align:start position:0% +elements in that class have a higher +conductivity a lower resistivity yep + + align:start position:0% +conductivity a lower resistivity yep + + + align:start position:0% +conductivity a lower resistivity yep +question copper doesn't seem that much + + align:start position:0% +question copper doesn't seem that much + + + align:start position:0% +question copper doesn't seem that much +worse than Sil reason so um yes + + align:start position:0% +worse than Sil reason so um yes + + + align:start position:0% +worse than Sil reason so um yes +absolutely uh copper doesn't seem so + + align:start position:0% +absolutely uh copper doesn't seem so + + + align:start position:0% +absolutely uh copper doesn't seem so +much worse than silver uh so uh the uh + + align:start position:0% +much worse than silver uh so uh the uh + + + align:start position:0% +much worse than silver uh so uh the uh +contact metallization pastes to date + + align:start position:0% +contact metallization pastes to date + + + align:start position:0% +contact metallization pastes to date +have mostly been using silver uh copper + + align:start position:0% +have mostly been using silver uh copper + + + align:start position:0% +have mostly been using silver uh copper +uh can oxidized fairly easily um so + + align:start position:0% +uh can oxidized fairly easily um so + + + align:start position:0% +uh can oxidized fairly easily um so +that's one one downside of copper uh + + align:start position:0% +that's one one downside of copper uh + + + align:start position:0% +that's one one downside of copper uh +another uh problem with copper is that + + align:start position:0% +another uh problem with copper is that + + + align:start position:0% +another uh problem with copper is that +it's a very fast diffuser uh it's very + + align:start position:0% +it's a very fast diffuser uh it's very + + + align:start position:0% +it's a very fast diffuser uh it's very +tiny uh and so the elastic strain energy + + align:start position:0% +tiny uh and so the elastic strain energy + + + align:start position:0% +tiny uh and so the elastic strain energy +term as it tries to move through a + + align:start position:0% +term as it tries to move through a + + + align:start position:0% +term as it tries to move through a +lattice is very small uh and as a result + + align:start position:0% +lattice is very small uh and as a result + + + align:start position:0% +lattice is very small uh and as a result +it goes deep so when you fire your + + align:start position:0% +it goes deep so when you fire your + + + align:start position:0% +it goes deep so when you fire your +contact metalization when you create the + + align:start position:0% +contact metalization when you create the + + + align:start position:0% +contact metalization when you create the +contact between your metal and your + + align:start position:0% +contact between your metal and your + + + align:start position:0% +contact between your metal and your +semiconductor underneath you run the + + align:start position:0% +semiconductor underneath you run the + + + align:start position:0% +semiconductor underneath you run the +risk of having atoms diffuse into your + + align:start position:0% +risk of having atoms diffuse into your + + + align:start position:0% +risk of having atoms diffuse into your +device and uh hurting the efficiency uh + + align:start position:0% +device and uh hurting the efficiency uh + + + align:start position:0% +device and uh hurting the efficiency uh +hurting the uh ability of the solar cell + + align:start position:0% +hurting the uh ability of the solar cell + + + align:start position:0% +hurting the uh ability of the solar cell +to collect carriers we'll hear more + + align:start position:0% +to collect carriers we'll hear more + + + align:start position:0% +to collect carriers we'll hear more +about that on Tuesday so it becomes an + + align:start position:0% +about that on Tuesday so it becomes an + + + align:start position:0% +about that on Tuesday so it becomes an +impurity yeah exactly it becomes an + + align:start position:0% +impurity yeah exactly it becomes an + + + align:start position:0% +impurity yeah exactly it becomes an +impurity in this case unintentional so + + align:start position:0% +impurity in this case unintentional so + + + align:start position:0% +impurity in this case unintentional so +uh just remember where the contact is + + align:start position:0% +uh just remember where the contact is + + + align:start position:0% +uh just remember where the contact is +right here in the emitter okay if it + + align:start position:0% +right here in the emitter okay if it + + + align:start position:0% +right here in the emitter okay if it +diffuses into the emitter it's okay the + + align:start position:0% +diffuses into the emitter it's okay the + + + align:start position:0% +diffuses into the emitter it's okay the +electrons at this point are the majority + + align:start position:0% +electrons at this point are the majority + + + align:start position:0% +electrons at this point are the majority +carriers but if the metal diffuses all + + align:start position:0% +carriers but if the metal diffuses all + + + align:start position:0% +carriers but if the metal diffuses all +the way into the bulk the electrons + + align:start position:0% +the way into the bulk the electrons + + + align:start position:0% +the way into the bulk the electrons +inside of the bulk and here are minority + + align:start position:0% +inside of the bulk and here are minority + + + align:start position:0% +inside of the bulk and here are minority +carriers and they can be impacted by the + + align:start position:0% +carriers and they can be impacted by the + + + align:start position:0% +carriers and they can be impacted by the +presence of of that copper + + align:start position:0% + + + + align:start position:0% + +there all right so um I wanted to get + + align:start position:0% +there all right so um I wanted to get + + + align:start position:0% +there all right so um I wanted to get +through at least one more uh point to + + align:start position:0% +through at least one more uh point to + + + align:start position:0% +through at least one more uh point to +really set us up well uh on Tuesday we + + align:start position:0% +really set us up well uh on Tuesday we + + + align:start position:0% +really set us up well uh on Tuesday we +want to be able to calculate the firmy + + align:start position:0% +want to be able to calculate the firmy + + + align:start position:0% +want to be able to calculate the firmy +energy of a solar cell as a function of + + align:start position:0% +energy of a solar cell as a function of + + + align:start position:0% +energy of a solar cell as a function of +dopen concentration illumination + + align:start position:0% +dopen concentration illumination + + + align:start position:0% +dopen concentration illumination +condition and temperature so so far + + align:start position:0% +condition and temperature so so far + + + align:start position:0% +condition and temperature so so far +we've really talked about the fmy energy + + align:start position:0% +we've really talked about the fmy energy + + + align:start position:0% +we've really talked about the fmy energy +the chemical potential inside of a solar + + align:start position:0% +the chemical potential inside of a solar + + + align:start position:0% +the chemical potential inside of a solar +cell in handwavy terms we've talked + + align:start position:0% +cell in handwavy terms we've talked + + + align:start position:0% +cell in handwavy terms we've talked +about General Trends about how as we add + + align:start position:0% +about General Trends about how as we add + + + align:start position:0% +about General Trends about how as we add +more electrons to our system Say by + + align:start position:0% +more electrons to our system Say by + + + align:start position:0% +more electrons to our system Say by +doping we shift The Firm energy up + + align:start position:0% +doping we shift The Firm energy up + + + align:start position:0% +doping we shift The Firm energy up +because the average Ensemble energy of + + align:start position:0% +because the average Ensemble energy of + + + align:start position:0% +because the average Ensemble energy of +the electrons is increasing um but now + + align:start position:0% +the electrons is increasing um but now + + + align:start position:0% +the electrons is increasing um but now +we're going to be calculating it and + + align:start position:0% +we're going to be calculating it and + + + align:start position:0% +we're going to be calculating it and +determining how to calculate it so the + + align:start position:0% +determining how to calculate it so the + + + align:start position:0% +determining how to calculate it so the +question is um you know calculating fir + + align:start position:0% +question is um you know calculating fir + + + align:start position:0% +question is um you know calculating fir +energy so let's introduce A New Concept + + align:start position:0% +energy so let's introduce A New Concept + + + align:start position:0% +energy so let's introduce A New Concept +here so far we've talked about an energy + + align:start position:0% +here so far we've talked about an energy + + + align:start position:0% +here so far we've talked about an energy +band diagram and drawn our veence band + + align:start position:0% +band diagram and drawn our veence band + + + align:start position:0% +band diagram and drawn our veence band +and drawn our conduction band and of + + align:start position:0% +and drawn our conduction band and of + + + align:start position:0% +and drawn our conduction band and of +course the band Gap in between them + + align:start position:0% +course the band Gap in between them + + + align:start position:0% +course the band Gap in between them +we've drawn the veence band and + + align:start position:0% +we've drawn the veence band and + + + align:start position:0% +we've drawn the veence band and +conduction bands as if they were just + + align:start position:0% +conduction bands as if they were just + + + align:start position:0% +conduction bands as if they were just +Continuum uh density of States as if + + align:start position:0% +Continuum uh density of States as if + + + align:start position:0% +Continuum uh density of States as if +they were just these blocks where + + align:start position:0% +they were just these blocks where + + + align:start position:0% +they were just these blocks where +electrons could Pile in + + align:start position:0% +electrons could Pile in + + + align:start position:0% +electrons could Pile in +um in reality we have what's called a + + align:start position:0% +um in reality we have what's called a + + + align:start position:0% +um in reality we have what's called a +density of States um in the veilance + + align:start position:0% +density of States um in the veilance + + + align:start position:0% +density of States um in the veilance +band and a density of states in the + + align:start position:0% +band and a density of states in the + + + align:start position:0% +band and a density of states in the +conduction band uh if you want to think + + align:start position:0% +conduction band uh if you want to think + + + align:start position:0% +conduction band uh if you want to think +about electrons as cars the density of + + align:start position:0% +about electrons as cars the density of + + + align:start position:0% +about electrons as cars the density of +States could be considered the uh number + + align:start position:0% +States could be considered the uh number + + + align:start position:0% +States could be considered the uh number +of uh parking spaces there are per floor + + align:start position:0% +of uh parking spaces there are per floor + + + align:start position:0% +of uh parking spaces there are per floor +in a parking garage right as you + + align:start position:0% +in a parking garage right as you + + + align:start position:0% +in a parking garage right as you +increase the energy and in the case of a + + align:start position:0% +increase the energy and in the case of a + + + align:start position:0% +increase the energy and in the case of a +parking garage you increase your + + align:start position:0% +parking garage you increase your + + + align:start position:0% +parking garage you increase your +potential energy as you move your car + + align:start position:0% +potential energy as you move your car + + + align:start position:0% +potential energy as you move your car +higher and higher um and here you would + + align:start position:0% +higher and higher um and here you would + + + align:start position:0% +higher and higher um and here you would +be increasing the energy of the + + align:start position:0% +be increasing the energy of the + + + align:start position:0% +be increasing the energy of the +electrons as you go higher and higher + + align:start position:0% +electrons as you go higher and higher + + + align:start position:0% +electrons as you go higher and higher +the increase in the energy of holes as + + align:start position:0% +the increase in the energy of holes as + + + align:start position:0% +the increase in the energy of holes as +they go lower and lower so we have a + + align:start position:0% +they go lower and lower so we have a + + + align:start position:0% +they go lower and lower so we have a +certain density of states that is + + align:start position:0% +certain density of states that is + + + align:start position:0% +certain density of states that is +allowed uh inside of our semiconductor + + align:start position:0% +allowed uh inside of our semiconductor + + + align:start position:0% +allowed uh inside of our semiconductor +and there is a very small density of + + align:start position:0% +and there is a very small density of + + + align:start position:0% +and there is a very small density of +states right at the band Edge and that + + align:start position:0% +states right at the band Edge and that + + + align:start position:0% +states right at the band Edge and that +density of States typically increases as + + align:start position:0% +density of States typically increases as + + + align:start position:0% +density of States typically increases as +you go deeper and deeper into the + + align:start position:0% +you go deeper and deeper into the + + + align:start position:0% +you go deeper and deeper into the +bands so now um in at at at room temp at + + align:start position:0% +bands so now um in at at at room temp at + + + align:start position:0% +bands so now um in at at at room temp at +absolute zero and the person who + + align:start position:0% +absolute zero and the person who + + + align:start position:0% +absolute zero and the person who +probably knows more about absolute zero + + align:start position:0% +probably knows more about absolute zero + + + align:start position:0% +probably knows more about absolute zero +than anybody else here in this room is + + align:start position:0% +than anybody else here in this room is + + + align:start position:0% +than anybody else here in this room is +Christy Simmons in the back who for her + + align:start position:0% +Christy Simmons in the back who for her + + + align:start position:0% +Christy Simmons in the back who for her +PhD uh would work on very low + + align:start position:0% +PhD uh would work on very low + + + align:start position:0% +PhD uh would work on very low +temperature experiments down into the + + align:start position:0% +temperature experiments down into the + + + align:start position:0% +temperature experiments down into the +what tens of Melvin range tens of Melvin + + align:start position:0% +what tens of Melvin range tens of Melvin + + + align:start position:0% +what tens of Melvin range tens of Melvin +range it's very very cold um and if you + + align:start position:0% +range it's very very cold um and if you + + + align:start position:0% +range it's very very cold um and if you +cool things down if you cool things down + + align:start position:0% +cool things down if you cool things down + + + align:start position:0% +cool things down if you cool things down +a lot uh all the electrons that were + + align:start position:0% +a lot uh all the electrons that were + + + align:start position:0% +a lot uh all the electrons that were +excited will drop down say into the + + align:start position:0% +excited will drop down say into the + + + align:start position:0% +excited will drop down say into the +valence band right here and what this is + + align:start position:0% +valence band right here and what this is + + + align:start position:0% +valence band right here and what this is +represented is is a fil filled veence + + align:start position:0% +represented is is a fil filled veence + + + align:start position:0% +represented is is a fil filled veence +band right there and as you begin + + align:start position:0% +band right there and as you begin + + + align:start position:0% +band right there and as you begin +heating uh your system up some of the + + align:start position:0% +heating uh your system up some of the + + + align:start position:0% +heating uh your system up some of the +electrons will have the thermal energy + + align:start position:0% +electrons will have the thermal energy + + + align:start position:0% +electrons will have the thermal energy +to be excited across the bandap so + + align:start position:0% +to be excited across the bandap so + + + align:start position:0% +to be excited across the bandap so +thermally excited electrons here + + align:start position:0% +thermally excited electrons here + + + align:start position:0% +thermally excited electrons here +represented um in your conduction band + + align:start position:0% +represented um in your conduction band + + + align:start position:0% +represented um in your conduction band +so we have a certain number of thermally + + align:start position:0% +so we have a certain number of thermally + + + align:start position:0% +so we have a certain number of thermally +excited electrons here uh up into the uh + + align:start position:0% +excited electrons here uh up into the uh + + + align:start position:0% +excited electrons here uh up into the uh +up into the conduction + + align:start position:0% +up into the conduction + + + align:start position:0% +up into the conduction +band oh and um these carriers these + + align:start position:0% +band oh and um these carriers these + + + align:start position:0% +band oh and um these carriers these +carriers will call intrinsic carriers + + align:start position:0% +carriers will call intrinsic carriers + + + align:start position:0% +carriers will call intrinsic carriers +because they're not added by dopin we're + + align:start position:0% +because they're not added by dopin we're + + + align:start position:0% +because they're not added by dopin we're +not adding anything to the semiconductor + + align:start position:0% +not adding anything to the semiconductor + + + align:start position:0% +not adding anything to the semiconductor +to create dopin to uh generate new + + align:start position:0% +to create dopin to uh generate new + + + align:start position:0% +to create dopin to uh generate new +carriers these are intrinsic carriers + + align:start position:0% +carriers these are intrinsic carriers + + + align:start position:0% +carriers these are intrinsic carriers +because they came from the veence band + + align:start position:0% +because they came from the veence band + + + align:start position:0% +because they came from the veence band +went up to the conduction band so if we + + align:start position:0% +went up to the conduction band so if we + + + align:start position:0% +went up to the conduction band so if we +plot intrinsic carrier concentration as + + align:start position:0% +plot intrinsic carrier concentration as + + + align:start position:0% +plot intrinsic carrier concentration as +a function of temperature we see a curve + + align:start position:0% +a function of temperature we see a curve + + + align:start position:0% +a function of temperature we see a curve +that looks like this and it follows this + + align:start position:0% +that looks like this and it follows this + + + align:start position:0% +that looks like this and it follows this +expression right here which is called an + + align:start position:0% +expression right here which is called an + + + align:start position:0% +expression right here which is called an +uranous equation in a generic form um in + + align:start position:0% +uranous equation in a generic form um in + + + align:start position:0% +uranous equation in a generic form um in +this case it would be intrinsic carrier + + align:start position:0% +this case it would be intrinsic carrier + + + align:start position:0% +this case it would be intrinsic carrier +concentration as a function of + + align:start position:0% +concentration as a function of + + + align:start position:0% +concentration as a function of +temperature we'd have to substitute this + + align:start position:0% +temperature we'd have to substitute this + + + align:start position:0% +temperature we'd have to substitute this +big n here for intrinsic carrier + + align:start position:0% +big n here for intrinsic carrier + + + align:start position:0% +big n here for intrinsic carrier +concentration some exponential preactor + + align:start position:0% +concentration some exponential preactor + + + align:start position:0% +concentration some exponential preactor +and in an activation energy the + + align:start position:0% +and in an activation energy the + + + align:start position:0% +and in an activation energy the +activation energy being the energy + + align:start position:0% +activation energy being the energy + + + align:start position:0% +activation energy being the energy +needed to create that free carrier right + + align:start position:0% +needed to create that free carrier right + + + align:start position:0% +needed to create that free carrier right +the bang Gap energy in this case the + + align:start position:0% +the bang Gap energy in this case the + + + align:start position:0% +the bang Gap energy in this case the +activation energy divided by KBT the um + + align:start position:0% +activation energy divided by KBT the um + + + align:start position:0% +activation energy divided by KBT the um +KBT being boltzman's constant time + + align:start position:0% +KBT being boltzman's constant time + + + align:start position:0% +KBT being boltzman's constant time +temperature in Calvin now if we plot the + + align:start position:0% +temperature in Calvin now if we plot the + + + align:start position:0% +temperature in Calvin now if we plot the +the same functions that we just saw in + + align:start position:0% +the same functions that we just saw in + + + align:start position:0% +the same functions that we just saw in +the previous slide a little differently + + align:start position:0% +the previous slide a little differently + + + align:start position:0% +the previous slide a little differently +we plot 1/ T say 1 over T right there + + align:start position:0% +we plot 1/ T say 1 over T right there + + + align:start position:0% +we plot 1/ T say 1 over T right there +and we plot the log of this value so + + align:start position:0% +and we plot the log of this value so + + + align:start position:0% +and we plot the log of this value so +again log of this value we can read the + + align:start position:0% +again log of this value we can read the + + + align:start position:0% +again log of this value we can read the +activation energy off of the slope of + + align:start position:0% +activation energy off of the slope of + + + align:start position:0% +activation energy off of the slope of +this graph so that's why you typically + + align:start position:0% +this graph so that's why you typically + + + align:start position:0% +this graph so that's why you typically +see uranous plots plotted in this way 1 + + align:start position:0% +see uranous plots plotted in this way 1 + + + align:start position:0% +see uranous plots plotted in this way 1 +overt versus log of parameter because + + align:start position:0% +overt versus log of parameter because + + + align:start position:0% +overt versus log of parameter because +you can read the activation energy + + align:start position:0% +you can read the activation energy + + + align:start position:0% +you can read the activation energy +straight off of the graph it becomes + + align:start position:0% +straight off of the graph it becomes + + + align:start position:0% +straight off of the graph it becomes +very easy to see the carrier + + align:start position:0% +very easy to see the carrier + + + align:start position:0% +very easy to see the carrier +concentration so again at Absolute Zero + + align:start position:0% +concentration so again at Absolute Zero + + + align:start position:0% +concentration so again at Absolute Zero +at Absolute Zero we have um uh uh here + + align:start position:0% +at Absolute Zero we have um uh uh here + + + align:start position:0% +at Absolute Zero we have um uh uh here +the veilance band completely filled the + + align:start position:0% +the veilance band completely filled the + + + align:start position:0% +the veilance band completely filled the +conduction band completely empty in our + + align:start position:0% +conduction band completely empty in our + + + align:start position:0% +conduction band completely empty in our +semiconductor and the probability of + + align:start position:0% +semiconductor and the probability of + + + align:start position:0% +semiconductor and the probability of +occupancy of a state inside of our + + align:start position:0% +occupancy of a state inside of our + + + align:start position:0% +occupancy of a state inside of our +semiconductor is given by this box + + align:start position:0% +semiconductor is given by this box + + + align:start position:0% +semiconductor is given by this box +function right here now let's look at + + align:start position:0% +function right here now let's look at + + + align:start position:0% +function right here now let's look at +what happens when we Heat this up when + + align:start position:0% +what happens when we Heat this up when + + + align:start position:0% +what happens when we Heat this up when +we heat the sample up some of the + + align:start position:0% +we heat the sample up some of the + + + align:start position:0% +we heat the sample up some of the +electrons that were in the higher energy + + align:start position:0% +electrons that were in the higher energy + + + align:start position:0% +electrons that were in the higher energy +states are going to be excited so they + + align:start position:0% +states are going to be excited so they + + + align:start position:0% +states are going to be excited so they +used to be here in lower energy States + + align:start position:0% +used to be here in lower energy States + + + align:start position:0% +used to be here in lower energy States +they're going to be excited the higher + + align:start position:0% +they're going to be excited the higher + + + align:start position:0% +they're going to be excited the higher +energy states + + align:start position:0% +energy states + + + align:start position:0% +energy states +and the area of this little shape right + + align:start position:0% +and the area of this little shape right + + + align:start position:0% +and the area of this little shape right +here is equal to the area of that little + + align:start position:0% +here is equal to the area of that little + + + align:start position:0% +here is equal to the area of that little +shape right here because we have + + align:start position:0% +shape right here because we have + + + align:start position:0% +shape right here because we have +conservation of number of electrons in + + align:start position:0% +conservation of number of electrons in + + + align:start position:0% +conservation of number of electrons in +our + + align:start position:0% +our + + + align:start position:0% +our +system if we multiply this by the + + align:start position:0% +system if we multiply this by the + + + align:start position:0% +system if we multiply this by the +density of States this is the density of + + align:start position:0% +density of States this is the density of + + + align:start position:0% +density of States this is the density of +states in the veilance band minimized + + align:start position:0% +states in the veilance band minimized + + + align:start position:0% +states in the veilance band minimized +here at the band edges uh and and + + align:start position:0% +here at the band edges uh and and + + + align:start position:0% +here at the band edges uh and and +increasing as we go deeper into the + + align:start position:0% +increasing as we go deeper into the + + + align:start position:0% +increasing as we go deeper into the +bands for the valance band and the + + align:start position:0% +bands for the valance band and the + + + align:start position:0% +bands for the valance band and the +conduction band so we take our + + align:start position:0% +conduction band so we take our + + + align:start position:0% +conduction band so we take our +probability distribution function + + align:start position:0% +probability distribution function + + + align:start position:0% +probability distribution function +multiply it by the density of states and + + align:start position:0% +multiply it by the density of states and + + + align:start position:0% +multiply it by the density of states and +we get the occupied density of states in + + align:start position:0% +we get the occupied density of states in + + + align:start position:0% +we get the occupied density of states in +our semiconductor so now we see that + + align:start position:0% +our semiconductor so now we see that + + + align:start position:0% +our semiconductor so now we see that +there's some uh number of missing + + align:start position:0% +there's some uh number of missing + + + align:start position:0% +there's some uh number of missing +electrons that are now in the conduction + + align:start position:0% +electrons that are now in the conduction + + + align:start position:0% +electrons that are now in the conduction +band they used to be in the valence band + + align:start position:0% +band they used to be in the valence band + + + align:start position:0% +band they used to be in the valence band +at very low temperature but now as we + + align:start position:0% +at very low temperature but now as we + + + align:start position:0% +at very low temperature but now as we +increase the temperature they've had the + + align:start position:0% +increase the temperature they've had the + + + align:start position:0% +increase the temperature they've had the +thermal energy to excite across given + + align:start position:0% +thermal energy to excite across given + + + align:start position:0% +thermal energy to excite across given +this probability distribution + + align:start position:0% +this probability distribution + + + align:start position:0% +this probability distribution +function and these carriers are now free + + align:start position:0% +function and these carriers are now free + + + align:start position:0% +function and these carriers are now free +to conduct charge inside of our + + align:start position:0% +to conduct charge inside of our + + + align:start position:0% +to conduct charge inside of our +system so what can we do with this + + align:start position:0% +system so what can we do with this + + + align:start position:0% +system so what can we do with this +framework with this understanding well + + align:start position:0% +framework with this understanding well + + + align:start position:0% +framework with this understanding well +um we can uh we can look at this uh + + align:start position:0% +um we can uh we can look at this uh + + + align:start position:0% +um we can uh we can look at this uh +function here and ask ourselves what is + + align:start position:0% +function here and ask ourselves what is + + + align:start position:0% +function here and ask ourselves what is +the name of that function it's called + + align:start position:0% +the name of that function it's called + + + align:start position:0% +the name of that function it's called +the firir distribution and it's given by + + align:start position:0% +the firir distribution and it's given by + + + align:start position:0% +the firir distribution and it's given by +this equation right here we'll notice in + + align:start position:0% +this equation right here we'll notice in + + + align:start position:0% +this equation right here we'll notice in +the firir distribution we'll notice that + + align:start position:0% +the firir distribution we'll notice that + + + align:start position:0% +the firir distribution we'll notice that +this + + align:start position:0% +this + + + align:start position:0% +this +equation um approximates to an + + align:start position:0% +equation um approximates to an + + + align:start position:0% +equation um approximates to an +exponential equation as we M move + + align:start position:0% +exponential equation as we M move + + + align:start position:0% +exponential equation as we M move +further and further away from the firm + + align:start position:0% +further and further away from the firm + + + align:start position:0% +further and further away from the firm +energy The Firm energy being defined as + + align:start position:0% +energy The Firm energy being defined as + + + align:start position:0% +energy The Firm energy being defined as +this energy right here if we move + + align:start position:0% +this energy right here if we move + + + align:start position:0% +this energy right here if we move +further way down here or further way up + + align:start position:0% +further way down here or further way up + + + align:start position:0% +further way down here or further way up +here this starts looking awful lot like + + align:start position:0% +here this starts looking awful lot like + + + align:start position:0% +here this starts looking awful lot like +an exponential meaning this right here + + align:start position:0% +an exponential meaning this right here + + + align:start position:0% +an exponential meaning this right here +and this right here start looking like + + align:start position:0% +and this right here start looking like + + + align:start position:0% +and this right here start looking like +exponential + + align:start position:0% +exponential + + + align:start position:0% +exponential +functions okay so let's um do a quick + + align:start position:0% +functions okay so let's um do a quick + + + align:start position:0% +functions okay so let's um do a quick +little gunan experiment a quick little + + align:start position:0% +little gunan experiment a quick little + + + align:start position:0% +little gunan experiment a quick little +thought experiment about what happens + + align:start position:0% +thought experiment about what happens + + + align:start position:0% +thought experiment about what happens +when we heat up a semiconductor and how + + align:start position:0% +when we heat up a semiconductor and how + + + align:start position:0% +when we heat up a semiconductor and how +would this impact how would these free + + align:start position:0% +would this impact how would these free + + + align:start position:0% +would this impact how would these free +carriers right here impact um the uh the + + align:start position:0% +carriers right here impact um the uh the + + + align:start position:0% +carriers right here impact um the uh the +noise say in in in a camera a a CCD + + align:start position:0% +noise say in in in a camera a a CCD + + + align:start position:0% +noise say in in in a camera a a CCD +based camera a charge couple display + + align:start position:0% +based camera a charge couple display + + + align:start position:0% +based camera a charge couple display +camera which functions not so different + + align:start position:0% +camera which functions not so different + + + align:start position:0% +camera which functions not so different +from a solar cell device except that + + align:start position:0% +from a solar cell device except that + + + align:start position:0% +from a solar cell device except that +it's biased a little differently than + + align:start position:0% +it's biased a little differently than + + + align:start position:0% +it's biased a little differently than +actual solar cell device but it could be + + align:start position:0% +actual solar cell device but it could be + + + align:start position:0% +actual solar cell device but it could be +like a PN Junction uh P to be more + + align:start position:0% +like a PN Junction uh P to be more + + + align:start position:0% +like a PN Junction uh P to be more +precise so we have um + + align:start position:0% +precise so we have um + + + align:start position:0% +precise so we have um +our little camera right here and inside + + align:start position:0% +our little camera right here and inside + + + align:start position:0% +our little camera right here and inside +of + + align:start position:0% +of + + + align:start position:0% +of +a the camera is typically placed inside + + align:start position:0% +a the camera is typically placed inside + + + align:start position:0% +a the camera is typically placed inside +of a liquid nitrogen Durer if we want + + align:start position:0% +of a liquid nitrogen Durer if we want + + + align:start position:0% +of a liquid nitrogen Durer if we want +very high performance uh these are not + + align:start position:0% +very high performance uh these are not + + + align:start position:0% +very high performance uh these are not +your typical handheld cameras that you + + align:start position:0% +your typical handheld cameras that you + + + align:start position:0% +your typical handheld cameras that you +would use for shots in the street these + + align:start position:0% +would use for shots in the street these + + + align:start position:0% +would use for shots in the street these +are cameras that we use in the + + align:start position:0% +are cameras that we use in the + + + align:start position:0% +are cameras that we use in the +laboratory for detecting very faint + + align:start position:0% +laboratory for detecting very faint + + + align:start position:0% +laboratory for detecting very faint +signals inside of our uh semiconductor + + align:start position:0% +signals inside of our uh semiconductor + + + align:start position:0% +signals inside of our uh semiconductor +systems and we typically cool our + + align:start position:0% +systems and we typically cool our + + + align:start position:0% +systems and we typically cool our +cameras down why because we want to + + align:start position:0% +cameras down why because we want to + + + align:start position:0% +cameras down why because we want to +minimize the density of these intrinsic + + align:start position:0% +minimize the density of these intrinsic + + + align:start position:0% +minimize the density of these intrinsic +carriers + + align:start position:0% +carriers + + + align:start position:0% +carriers +because any Photon that comes into our + + align:start position:0% +because any Photon that comes into our + + + align:start position:0% +because any Photon that comes into our +system we want to be able to count it + + align:start position:0% +system we want to be able to count it + + + align:start position:0% +system we want to be able to count it +and to detect it and not have to detect + + align:start position:0% +and to detect it and not have to detect + + + align:start position:0% +and to detect it and not have to detect +a very small signal on top of a large + + align:start position:0% +a very small signal on top of a large + + + align:start position:0% +a very small signal on top of a large +background noise of thermally excited + + align:start position:0% +background noise of thermally excited + + + align:start position:0% +background noise of thermally excited +carriers in a solar cell device um the + + align:start position:0% +carriers in a solar cell device um the + + + align:start position:0% +carriers in a solar cell device um the +intrinsic carrier concentration is + + align:start position:0% +intrinsic carrier concentration is + + + align:start position:0% +intrinsic carrier concentration is +typically much much less than the uh + + align:start position:0% +typically much much less than the uh + + + align:start position:0% +typically much much less than the uh +dopent concentration so the intrinsic + + align:start position:0% +dopent concentration so the intrinsic + + + align:start position:0% +dopent concentration so the intrinsic +carrier concentration matters less for + + align:start position:0% +carrier concentration matters less for + + + align:start position:0% +carrier concentration matters less for +our semiconductors than it does for a + + align:start position:0% +our semiconductors than it does for a + + + align:start position:0% +our semiconductors than it does for a +photo detector uh like this and that's + + align:start position:0% +photo detector uh like this and that's + + + align:start position:0% +photo detector uh like this and that's +why thankfully we don't have to cool our + + align:start position:0% +why thankfully we don't have to cool our + + + align:start position:0% +why thankfully we don't have to cool our +solar cells with li nitrogen + + align:start position:0% +solar cells with li nitrogen + + + align:start position:0% +solar cells with li nitrogen +so um in terms of of of uh intrinsic + + align:start position:0% +so um in terms of of of uh intrinsic + + + align:start position:0% +so um in terms of of of uh intrinsic +carriers let's dwell there just a little + + align:start position:0% +carriers let's dwell there just a little + + + align:start position:0% +carriers let's dwell there just a little +bit longer transistors are made of what + + align:start position:0% +bit longer transistors are made of what + + + align:start position:0% +bit longer transistors are made of what +semiconductor material to uh have uh + + align:start position:0% +semiconductor material to uh have uh + + + align:start position:0% +semiconductor material to uh have uh +less electronic noise uh to experience + + align:start position:0% +less electronic noise uh to experience + + + align:start position:0% +less electronic noise uh to experience +okay so what semiconductor material + + align:start position:0% +okay so what semiconductor material + + + align:start position:0% +okay so what semiconductor material +geranium or silicon would experience + + align:start position:0% +geranium or silicon would experience + + + align:start position:0% +geranium or silicon would experience +less electronic noise at room + + align:start position:0% +less electronic noise at room + + + align:start position:0% +less electronic noise at room +temperature and let me give you a hint + + align:start position:0% +temperature and let me give you a hint + + + align:start position:0% +temperature and let me give you a hint +silicon has a band gap of 1.1 EV + + align:start position:0% +silicon has a band gap of 1.1 EV + + + align:start position:0% +silicon has a band gap of 1.1 EV +germanium has a band gap of 0.67 EV + + align:start position:0% +germanium has a band gap of 0.67 EV + + + align:start position:0% +germanium has a band gap of 0.67 EV +which of the two is going to have + + align:start position:0% +which of the two is going to have + + + align:start position:0% +which of the two is going to have +greater electronic noise at room + + align:start position:0% +greater electronic noise at room + + + align:start position:0% +greater electronic noise at room +temperature germanium because as a + + align:start position:0% +temperature germanium because as a + + + align:start position:0% +temperature germanium because as a +smaller band Gap it's going to be easier + + align:start position:0% +smaller band Gap it's going to be easier + + + align:start position:0% +smaller band Gap it's going to be easier +for the carriers where you go all the + + align:start position:0% +for the carriers where you go all the + + + align:start position:0% +for the carriers where you go all the +way back here it's going to be easier + + align:start position:0% +way back here it's going to be easier + + + align:start position:0% +way back here it's going to be easier +for carriers to hop across because the + + align:start position:0% +for carriers to hop across because the + + + align:start position:0% +for carriers to hop across because the +band Gap is smaller another way to look + + align:start position:0% +band Gap is smaller another way to look + + + align:start position:0% +band Gap is smaller another way to look +at it is on the uranous plot you'll have + + align:start position:0% +at it is on the uranous plot you'll have + + + align:start position:0% +at it is on the uranous plot you'll have +a higher carrier concentration because + + align:start position:0% +a higher carrier concentration because + + + align:start position:0% +a higher carrier concentration because +your slope is smaller your activation + + align:start position:0% +your slope is smaller your activation + + + align:start position:0% +your slope is smaller your activation +energy is smaller and as a result you'll + + align:start position:0% +energy is smaller and as a result you'll + + + align:start position:0% +energy is smaller and as a result you'll +have a higher uh if the band Gap shrinks + + align:start position:0% +have a higher uh if the band Gap shrinks + + + align:start position:0% +have a higher uh if the band Gap shrinks +you'll have a higher carrier density + + align:start position:0% +you'll have a higher carrier density + + + align:start position:0% +you'll have a higher carrier density +here in the conduction band let me show + + align:start position:0% +here in the conduction band let me show + + + align:start position:0% +here in the conduction band let me show +you that in pictoral form so this is the + + align:start position:0% +you that in pictoral form so this is the + + + align:start position:0% +you that in pictoral form so this is the +Silicon band Gap this is the density of + + align:start position:0% +Silicon band Gap this is the density of + + + align:start position:0% +Silicon band Gap this is the density of +thermally excited carriers for silicon + + align:start position:0% +thermally excited carriers for silicon + + + align:start position:0% +thermally excited carriers for silicon +now we shrink the band Gap boom We + + align:start position:0% +now we shrink the band Gap boom We + + + align:start position:0% +now we shrink the band Gap boom We +Shrunk it same probability distribution + + align:start position:0% +Shrunk it same probability distribution + + + align:start position:0% +Shrunk it same probability distribution +function because we're at the same + + align:start position:0% +function because we're at the same + + + align:start position:0% +function because we're at the same +temperature but now we have a smaller + + align:start position:0% +temperature but now we have a smaller + + + align:start position:0% +temperature but now we have a smaller +band Gap so we have a higher density of + + align:start position:0% +band Gap so we have a higher density of + + + align:start position:0% +band Gap so we have a higher density of +free carriers and true story geranium + + align:start position:0% +free carriers and true story geranium + + + align:start position:0% +free carriers and true story geranium +was one of the first crystals to be uh + + align:start position:0% +was one of the first crystals to be uh + + + align:start position:0% +was one of the first crystals to be uh +purified uh during the early days of + + align:start position:0% +purified uh during the early days of + + + align:start position:0% +purified uh during the early days of +semiconductors and silicon was following + + align:start position:0% +semiconductors and silicon was following + + + align:start position:0% +semiconductors and silicon was following +germanium uh and silicon was ultimately + + align:start position:0% +germanium uh and silicon was ultimately + + + align:start position:0% +germanium uh and silicon was ultimately +chosen as the uh material of choice for + + align:start position:0% +chosen as the uh material of choice for + + + align:start position:0% +chosen as the uh material of choice for +transistors because the intrinsic + + align:start position:0% +transistors because the intrinsic + + + align:start position:0% +transistors because the intrinsic +carrier concentration of geranium was + + align:start position:0% +carrier concentration of geranium was + + + align:start position:0% +carrier concentration of geranium was +just too high for most uh applications + + align:start position:0% +just too high for most uh applications + + + align:start position:0% +just too high for most uh applications +and so you can see the intrinsic carrier + + align:start position:0% +and so you can see the intrinsic carrier + + + align:start position:0% +and so you can see the intrinsic carrier +concentration at room temperature of + + align:start position:0% +concentration at room temperature of + + + align:start position:0% +concentration at room temperature of +silicon is around 10 10 whereas for + + align:start position:0% +silicon is around 10 10 whereas for + + + align:start position:0% +silicon is around 10 10 whereas for +geranium is around 10^ 13 uh three + + align:start position:0% +geranium is around 10^ 13 uh three + + + align:start position:0% +geranium is around 10^ 13 uh three +orders of magnitude higher so yes + + align:start position:0% +orders of magnitude higher so yes + + + align:start position:0% +orders of magnitude higher so yes +question last + + align:start position:0% + + + + align:start position:0% + +wey + + align:start position:0% +wey + + + align:start position:0% +wey +cells would be a much better choice than + + align:start position:0% +cells would be a much better choice than + + + align:start position:0% +cells would be a much better choice than +I'm just assuming is that more like a + + align:start position:0% +I'm just assuming is that more like a + + + align:start position:0% +I'm just assuming is that more like a +cost thing it would be mostly a cost + + align:start position:0% +cost thing it would be mostly a cost + + + align:start position:0% +cost thing it would be mostly a cost +thing absolutely um and so you do see + + align:start position:0% +thing absolutely um and so you do see + + + align:start position:0% +thing absolutely um and so you do see +solar cells like concentric is one + + align:start position:0% +solar cells like concentric is one + + + align:start position:0% +solar cells like concentric is one +company that's commercializing Gallum + + align:start position:0% +company that's commercializing Gallum + + + align:start position:0% +company that's commercializing Gallum +aride based solar cells but they have to + + align:start position:0% +aride based solar cells but they have to + + + align:start position:0% +aride based solar cells but they have to +uh concentrate the sunlight into very + + align:start position:0% +uh concentrate the sunlight into very + + + align:start position:0% +uh concentrate the sunlight into very +small area devices because the devices + + align:start position:0% +small area devices because the devices + + + align:start position:0% +small area devices because the devices +cost so much to make per unit area so + + align:start position:0% +cost so much to make per unit area so + + + align:start position:0% +cost so much to make per unit area so +they take cheap plastic and and + + align:start position:0% +they take cheap plastic and and + + + align:start position:0% +they take cheap plastic and and +concentrate the sunlight + + align:start position:0% +concentrate the sunlight + + + align:start position:0% +concentrate the sunlight +down yeah and here's Gallum arsenide the + + align:start position:0% +down yeah and here's Gallum arsenide the + + + align:start position:0% +down yeah and here's Gallum arsenide the +intrinsic carrier concentration is even + + align:start position:0% +intrinsic carrier concentration is even + + + align:start position:0% +intrinsic carrier concentration is even +less than that of silicon because the + + align:start position:0% +less than that of silicon because the + + + align:start position:0% +less than that of silicon because the +band Gap is 1.4 EV instead of + + align:start position:0% +band Gap is 1.4 EV instead of + + + align:start position:0% +band Gap is 1.4 EV instead of +1.1 okay so I think this is a good place + + align:start position:0% +1.1 okay so I think this is a good place + + + align:start position:0% +1.1 okay so I think this is a good place +to stop I'm still not through all the + + align:start position:0% +to stop I'm still not through all the + + + align:start position:0% +to stop I'm still not through all the +material um oh we wanted to do one demo + + align:start position:0% +material um oh we wanted to do one demo + + + align:start position:0% +material um oh we wanted to do one demo +yeah uh do you want to do it first thing + + align:start position:0% +yeah uh do you want to do it first thing + + + align:start position:0% +yeah uh do you want to do it first thing +next lecture that's fine got ah we we do + + align:start position:0% +next lecture that's fine got ah we we do + + + align:start position:0% +next lecture that's fine got ah we we do +have five more minutes before 10 after + + align:start position:0% +have five more minutes before 10 after + + + align:start position:0% +have five more minutes before 10 after +okay why don't we do a quick demo then + + align:start position:0% +okay why don't we do a quick demo then + + + align:start position:0% +okay why don't we do a quick demo then +um so what we're going to do is Joe sets + + align:start position:0% +um so what we're going to do is Joe sets + + + align:start position:0% +um so what we're going to do is Joe sets +us up is I'll I'll I'll verly describe + + align:start position:0% +us up is I'll I'll I'll verly describe + + + align:start position:0% +us up is I'll I'll I'll verly describe +what's going to happen here um we are + + align:start position:0% +what's going to happen here um we are + + + align:start position:0% +what's going to happen here um we are +going to take uh this actually let me go + + align:start position:0% +going to take uh this actually let me go + + + align:start position:0% +going to take uh this actually let me go +back to the affir distribution function + + align:start position:0% +back to the affir distribution function + + + align:start position:0% +back to the affir distribution function +this function right here as we increase + + align:start position:0% +this function right here as we increase + + + align:start position:0% +this function right here as we increase +temperature what happens to this this + + align:start position:0% +temperature what happens to this this + + + align:start position:0% +temperature what happens to this this +will look more and more + + align:start position:0% +will look more and more + + + align:start position:0% +will look more and more +uh shall we say uh flat it won't + + align:start position:0% +uh shall we say uh flat it won't + + + align:start position:0% +uh shall we say uh flat it won't +actually go flat but it'll become more + + align:start position:0% +actually go flat but it'll become more + + + align:start position:0% +actually go flat but it'll become more +and more diagonal as opposed to box like + + align:start position:0% +and more diagonal as opposed to box like + + + align:start position:0% +and more diagonal as opposed to box like +in function what that means is the + + align:start position:0% +in function what that means is the + + + align:start position:0% +in function what that means is the +density of carriers the density of free + + align:start position:0% +density of carriers the density of free + + + align:start position:0% +density of carriers the density of free +carriers will increase with temperature + + align:start position:0% +carriers will increase with temperature + + + align:start position:0% +carriers will increase with temperature +and because of the uranous dependence + + align:start position:0% +and because of the uranous dependence + + + align:start position:0% +and because of the uranous dependence +here we have an exponential increase of + + align:start position:0% +here we have an exponential increase of + + + align:start position:0% +here we have an exponential increase of +the number of free carriers with + + align:start position:0% +the number of free carriers with + + + align:start position:0% +the number of free carriers with +temperature uh because the function + + align:start position:0% +temperature uh because the function + + + align:start position:0% +temperature uh because the function +right around this region right here + + align:start position:0% +right around this region right here + + + align:start position:0% +right around this region right here +which impacts the uh electron + + align:start position:0% +which impacts the uh electron + + + align:start position:0% +which impacts the uh electron +concentration the conduction band uh + + align:start position:0% +concentration the conduction band uh + + + align:start position:0% +concentration the conduction band uh +this small portion of the fidi equation + + align:start position:0% +this small portion of the fidi equation + + + align:start position:0% +this small portion of the fidi equation +can be approximated by an exponential if + + align:start position:0% +can be approximated by an exponential if + + + align:start position:0% +can be approximated by an exponential if +we have an increasing temperature we + + align:start position:0% +we have an increasing temperature we + + + align:start position:0% +we have an increasing temperature we +should have a drastically increasing + + align:start position:0% +should have a drastically increasing + + + align:start position:0% +should have a drastically increasing +carrier density and let's see if that's + + align:start position:0% +carrier density and let's see if that's + + + align:start position:0% +carrier density and let's see if that's +indeed the case what we have is a piece + + align:start position:0% +indeed the case what we have is a piece + + + align:start position:0% +indeed the case what we have is a piece +of intrinsic silicon uh just with a a + + align:start position:0% +of intrinsic silicon uh just with a a + + + align:start position:0% +of intrinsic silicon uh just with a a +battery pack attached so we have a a + + align:start position:0% +battery pack attached so we have a a + + + align:start position:0% +battery pack attached so we have a a +field across that piece of intrinsic + + align:start position:0% +field across that piece of intrinsic + + + align:start position:0% +field across that piece of intrinsic +silicon oops here we go and we are going + + align:start position:0% +silicon oops here we go and we are going + + + align:start position:0% +silicon oops here we go and we are going +to apply again that field across the + + align:start position:0% +to apply again that field across the + + + align:start position:0% +to apply again that field across the +intrinsic piece of silicon a certain + + align:start position:0% +intrinsic piece of silicon a certain + + + align:start position:0% +intrinsic piece of silicon a certain +current will flow through it um and then + + align:start position:0% +current will flow through it um and then + + + align:start position:0% +current will flow through it um and then +Joe has a heat gun so he's going to heat + + align:start position:0% +Joe has a heat gun so he's going to heat + + + align:start position:0% +Joe has a heat gun so he's going to heat +up the Silicon + + align:start position:0% +up the Silicon + + + align:start position:0% +up the Silicon +uh and see what happens as the fidra uh + + align:start position:0% +uh and see what happens as the fidra uh + + + align:start position:0% +uh and see what happens as the fidra uh +equation here is affected by temperature + + align:start position:0% +equation here is affected by temperature + + + align:start position:0% +equation here is affected by temperature +we should have an increasing density of + + align:start position:0% +we should have an increasing density of + + + align:start position:0% +we should have an increasing density of +carriers in the conduction band uh so + + align:start position:0% +carriers in the conduction band uh so + + + align:start position:0% +carriers in the conduction band uh so +let's see if that's indeed the case can + + align:start position:0% +let's see if that's indeed the case can + + + align:start position:0% +let's see if that's indeed the case can +somebody read off what the uh current is + + align:start position:0% +somebody read off what the uh current is + + + align:start position:0% +somebody read off what the uh current is +currently measuring there on our current + + align:start position:0% +currently measuring there on our current + + + align:start position:0% +currently measuring there on our current +meter it's about 9.8 microamps right now + + align:start position:0% +meter it's about 9.8 microamps right now + + + align:start position:0% +meter it's about 9.8 microamps right now +9.8 microamps so this battery pack of 3 + + align:start position:0% +9.8 microamps so this battery pack of 3 + + + align:start position:0% +9.8 microamps so this battery pack of 3 +volts right here is um is forcing a + + align:start position:0% +volts right here is um is forcing a + + + align:start position:0% +volts right here is um is forcing a +current of 9.8 microamps across that + + align:start position:0% +current of 9.8 microamps across that + + + align:start position:0% +current of 9.8 microamps across that +little slab of silicon + + align:start position:0% +little slab of silicon + + + align:start position:0% +little slab of silicon +uh that is SED right here and so Joe is + + align:start position:0% +uh that is SED right here and so Joe is + + + align:start position:0% +uh that is SED right here and so Joe is +going to apply the heat gun and if none + + align:start position:0% +going to apply the heat gun and if none + + + align:start position:0% +going to apply the heat gun and if none +of the contacts pop off uh let's see + + align:start position:0% +of the contacts pop off uh let's see + + + align:start position:0% +of the contacts pop off uh let's see +what uh let's see what will happen so we + + align:start position:0% +what uh let's see what will happen so we + + + align:start position:0% +what uh let's see what will happen so we +expect the resistivity uh to go what + + align:start position:0% +expect the resistivity uh to go what + + + align:start position:0% +expect the resistivity uh to go what +down and the conductivity to go up all + + align:start position:0% +down and the conductivity to go up all + + + align:start position:0% +down and the conductivity to go up all +right so let's see + + align:start position:0% + + + + align:start position:0% + +here so what's happening there + + align:start position:0% +here so what's happening there + + + align:start position:0% +here so what's happening there +folks it's going up so that's the + + align:start position:0% +folks it's going up so that's the + + + align:start position:0% +folks it's going up so that's the +uh so it went up to around 50 microG and + + align:start position:0% +uh so it went up to around 50 microG and + + + align:start position:0% +uh so it went up to around 50 microG and +you can see it's dropping R + + align:start position:0% +you can see it's dropping R + + + align:start position:0% +you can see it's dropping R +dramatically so the current that the + + align:start position:0% +dramatically so the current that the + + + align:start position:0% +dramatically so the current that the +material is able to pass through is + + align:start position:0% +material is able to pass through is + + + align:start position:0% +material is able to pass through is +increasing as a result of uh the + + align:start position:0% +increasing as a result of uh the + + + align:start position:0% +increasing as a result of uh the +increasing temperature because you're + + align:start position:0% +increasing temperature because you're + + + align:start position:0% +increasing temperature because you're +exciting more carriers into the + + align:start position:0% +exciting more carriers into the + + + align:start position:0% +exciting more carriers into the +conduction band leaving more holes in + + align:start position:0% +conduction band leaving more holes in + + + align:start position:0% +conduction band leaving more holes in +the veilance band and these are free + + align:start position:0% +the veilance band and these are free + + + align:start position:0% +the veilance band and these are free +charge carriers that are able to conduct + + align:start position:0% +charge carriers that are able to conduct + + + align:start position:0% +charge carriers that are able to conduct +charge through the + + align:start position:0% +charge through the + + + align:start position:0% +charge through the +material cool okay so uh with that I + + align:start position:0% +material cool okay so uh with that I + + + align:start position:0% +material cool okay so uh with that I +will leave you and we'll return Tuesday + + align:start position:0% +will leave you and we'll return Tuesday + + + align:start position:0% +will leave you and we'll return Tuesday +and Joe will give a fantastic lecture on + + align:start position:0% +and Joe will give a fantastic lecture on + + + align:start position:0% +and Joe will give a fantastic lecture on +uh device physics as well uh since will + + align:start position:0% +uh device physics as well uh since will + + + align:start position:0% +uh device physics as well uh since will +be at a kickoff meeting at for a big NSF + + align:start position:0% +be at a kickoff meeting at for a big NSF + + + align:start position:0% +be at a kickoff meeting at for a big NSF +related Center in Phoenix Arizona but it + + align:start position:0% +related Center in Phoenix Arizona but it + + + align:start position:0% +related Center in Phoenix Arizona but it +will be a great lecture uh you won't + + align:start position:0% +will be a great lecture uh you won't + + + align:start position:0% +will be a great lecture uh you won't +want to miss it and uh look forward to + + align:start position:0% +want to miss it and uh look forward to + + + align:start position:0% +want to miss it and uh look forward to +seeing you on + + align:start position:0% + + + + align:start position:0% + +Tuesday \ No newline at end of file diff --git a/dgSFOyxFHW8.txt b/dgSFOyxFHW8.txt new file mode 100644 index 0000000000000000000000000000000000000000..51a1dbd5047c18db27d95041b8afbdebbf71ad79 --- /dev/null +++ b/dgSFOyxFHW8.txt @@ -0,0 +1,1731 @@ +align:start position:0% + +And uh our our last um speaker for this + + align:start position:0% +And uh our our last um speaker for this + + + align:start position:0% +And uh our our last um speaker for this +session is Jonathan + + align:start position:0% +session is Jonathan + + + align:start position:0% +session is Jonathan +>> Buunor. + + align:start position:0% +>> Buunor. + + + align:start position:0% +>> Buunor. +I'm looking for a + + align:start position:0% +I'm looking for a + + + align:start position:0% +I'm looking for a +>> slide changer. This one + + align:start position:0% +>> slide changer. This one + + + align:start position:0% +>> slide changer. This one +>> is this the slide flipper? + + align:start position:0% +>> is this the slide flipper? + + + align:start position:0% +>> is this the slide flipper? +>> Yes. Okay, + + align:start position:0% +>> Yes. Okay, + + + align:start position:0% +>> Yes. Okay, +>> you got it. + + align:start position:0% +>> you got it. + + + align:start position:0% +>> you got it. +>> All right. Yeah. So, my my name is + + align:start position:0% +>> All right. Yeah. So, my my name is + + + align:start position:0% +>> All right. Yeah. So, my my name is +Jonathan Municore. I'm a assistant + + align:start position:0% +Jonathan Municore. I'm a assistant + + + align:start position:0% +Jonathan Municore. I'm a assistant +professor at Boston University School of + + align:start position:0% +professor at Boston University School of + + + align:start position:0% +professor at Boston University School of +Public Health. And uh my my goal in the + + align:start position:0% +Public Health. And uh my my goal in the + + + align:start position:0% +Public Health. And uh my my goal in the +next 10 minutes is to not only uh + + align:start position:0% +next 10 minutes is to not only uh + + + align:start position:0% +next 10 minutes is to not only uh +convince you that a person from public + + align:start position:0% +convince you that a person from public + + + align:start position:0% +convince you that a person from public +health belongs in the room, but also to + + align:start position:0% +health belongs in the room, but also to + + + align:start position:0% +health belongs in the room, but also to +uh convince you that you all are + + align:start position:0% +uh convince you that you all are + + + align:start position:0% +uh convince you that you all are +secretly um going to be public health + + align:start position:0% +secretly um going to be public health + + + align:start position:0% +secretly um going to be public health +professionals. Um so uh where I wanted + + align:start position:0% +professionals. Um so uh where I wanted + + + align:start position:0% +professionals. Um so uh where I wanted +to start was to look at this um process. + + align:start position:0% +to start was to look at this um process. + + + align:start position:0% +to start was to look at this um process. +This is how like uh EPA other + + align:start position:0% +This is how like uh EPA other + + + align:start position:0% +This is how like uh EPA other +environmental agencies um like help + + align:start position:0% +environmental agencies um like help + + + align:start position:0% +environmental agencies um like help +public health environmental health + + align:start position:0% +public health environmental health + + + align:start position:0% +public health environmental health +professionals look at um just hazards in + + align:start position:0% +professionals look at um just hazards in + + + align:start position:0% +professionals look at um just hazards in +the world. Um we do a lot of very fancy + + align:start position:0% +the world. Um we do a lot of very fancy + + + align:start position:0% +the world. Um we do a lot of very fancy +stuff but very often it breaks down into + + align:start position:0% +stuff but very often it breaks down into + + + align:start position:0% +stuff but very often it breaks down into +these four basic steps which is to start + + align:start position:0% +these four basic steps which is to start + + + align:start position:0% +these four basic steps which is to start +it start on the left to ask like is + + align:start position:0% +it start on the left to ask like is + + + align:start position:0% +it start on the left to ask like is +there some kind of pollutant a stressor + + align:start position:0% +there some kind of pollutant a stressor + + + align:start position:0% +there some kind of pollutant a stressor +something like that that people are + + align:start position:0% +something like that that people are + + + align:start position:0% +something like that that people are +being exposed to that might cause a + + align:start position:0% +being exposed to that might cause a + + + align:start position:0% +being exposed to that might cause a +problem could be you know air pollutant + + align:start position:0% +problem could be you know air pollutant + + + align:start position:0% +problem could be you know air pollutant +uh water pollutant heat um a safety + + align:start position:0% +uh water pollutant heat um a safety + + + align:start position:0% +uh water pollutant heat um a safety +issue um anything like anything that + + align:start position:0% +issue um anything like anything that + + + align:start position:0% +issue um anything like anything that +could harm people should go in that box. + + align:start position:0% +could harm people should go in that box. + + + align:start position:0% +could harm people should go in that box. +Um, next up is this dose response + + align:start position:0% +Um, next up is this dose response + + + align:start position:0% +Um, next up is this dose response +assessment. Um, where this is really + + align:start position:0% +assessment. Um, where this is really + + + align:start position:0% +assessment. Um, where this is really +just a process of asking like if there's + + align:start position:0% +just a process of asking like if there's + + + align:start position:0% +just a process of asking like if there's +a certain amount of this thing in the + + align:start position:0% +a certain amount of this thing in the + + + align:start position:0% +a certain amount of this thing in the +environment, what are the health + + align:start position:0% +environment, what are the health + + + align:start position:0% +environment, what are the health +problems at different levels of + + align:start position:0% +problems at different levels of + + + align:start position:0% +problems at different levels of +exposures? So like air high levels of + + align:start position:0% +exposures? So like air high levels of + + + align:start position:0% +exposures? So like air high levels of +air pollution or worse than uh lower + + align:start position:0% +air pollution or worse than uh lower + + + align:start position:0% +air pollution or worse than uh lower +levels of air pollution. Same goes for + + align:start position:0% +levels of air pollution. Same goes for + + + align:start position:0% +levels of air pollution. Same goes for +water pollution um and that kind of + + align:start position:0% +water pollution um and that kind of + + + align:start position:0% +water pollution um and that kind of +thing. The uh third step that goes in + + align:start position:0% +thing. The uh third step that goes in + + + align:start position:0% +thing. The uh third step that goes in +parallel with that is this exposure + + align:start position:0% +parallel with that is this exposure + + + align:start position:0% +parallel with that is this exposure +assessment step that asks um okay so we + + align:start position:0% +assessment step that asks um okay so we + + + align:start position:0% +assessment step that asks um okay so we +know that there's a thing that is bad. + + align:start position:0% +know that there's a thing that is bad. + + + align:start position:0% +know that there's a thing that is bad. +um how many people are exposed to it? + + align:start position:0% +um how many people are exposed to it? + + + align:start position:0% +um how many people are exposed to it? +How long are they exposed to it? Are + + align:start position:0% +How long are they exposed to it? Are + + + align:start position:0% +How long are they exposed to it? Are +there certain like um susceptible + + align:start position:0% +there certain like um susceptible + + + align:start position:0% +there certain like um susceptible +windows or susceptible populations like + + align:start position:0% +windows or susceptible populations like + + + align:start position:0% +windows or susceptible populations like +infants or um marginalized communities + + align:start position:0% +infants or um marginalized communities + + + align:start position:0% +infants or um marginalized communities +that are um exposed to this? And then in + + align:start position:0% +that are um exposed to this? And then in + + + align:start position:0% +that are um exposed to this? And then in +the end we have this fourth step called + + align:start position:0% +the end we have this fourth step called + + + align:start position:0% +the end we have this fourth step called +risk characterization which um basically + + align:start position:0% +risk characterization which um basically + + + align:start position:0% +risk characterization which um basically +just asks like how big of a deal is this + + align:start position:0% +just asks like how big of a deal is this + + + align:start position:0% +just asks like how big of a deal is this +anyway? Um, so what I've done and do + + align:start position:0% +anyway? Um, so what I've done and do + + + align:start position:0% +anyway? Um, so what I've done and do +occasionally is I put this uh flip these + + align:start position:0% +occasionally is I put this uh flip these + + + align:start position:0% +occasionally is I put this uh flip these +these four steps to look like one of + + align:start position:0% +these four steps to look like one of + + + align:start position:0% +these four steps to look like one of +these hazmat placards that you'll see on + + align:start position:0% +these hazmat placards that you'll see on + + + align:start position:0% +these hazmat placards that you'll see on +um like the the trucks going down the + + align:start position:0% +um like the the trucks going down the + + + align:start position:0% +um like the the trucks going down the +highway or whatever. Um and then um + + align:start position:0% +highway or whatever. Um and then um + + + align:start position:0% +highway or whatever. Um and then um +again here's a simple versions. Is there + + align:start position:0% +again here's a simple versions. Is there + + + align:start position:0% +again here's a simple versions. Is there +some is there something that might be + + align:start position:0% +some is there something that might be + + + align:start position:0% +some is there something that might be +harmful? How harmful is it if you're + + align:start position:0% +harmful? How harmful is it if you're + + + align:start position:0% +harmful? How harmful is it if you're +exposed? Uh how many people are exposed + + align:start position:0% +exposed? Uh how many people are exposed + + + align:start position:0% +exposed? Uh how many people are exposed +to it? And how big of a deal is this + + align:start position:0% +to it? And how big of a deal is this + + + align:start position:0% +to it? And how big of a deal is this +really? So four basic questions. Um now + + align:start position:0% +really? So four basic questions. Um now + + + align:start position:0% +really? So four basic questions. Um now +uh you can overlay this look at the full + + align:start position:0% +uh you can overlay this look at the full + + + align:start position:0% +uh you can overlay this look at the full +life cycle. This is supply chain of + + align:start position:0% +life cycle. This is supply chain of + + + align:start position:0% +life cycle. This is supply chain of +natural gas starting from your wells and + + align:start position:0% +natural gas starting from your wells and + + + align:start position:0% +natural gas starting from your wells and +everything on the left over to the + + align:start position:0% +everything on the left over to the + + + align:start position:0% +everything on the left over to the +right. Um all the gas consumers like + + align:start position:0% +right. Um all the gas consumers like + + + align:start position:0% +right. Um all the gas consumers like +your commercial buildings, your um + + align:start position:0% +your commercial buildings, your um + + + align:start position:0% +your commercial buildings, your um +residences, uh the use of gas and power + + align:start position:0% +residences, uh the use of gas and power + + + align:start position:0% +residences, uh the use of gas and power +plants and all the pipelines, storage + + align:start position:0% +plants and all the pipelines, storage + + + align:start position:0% +plants and all the pipelines, storage +facilities, compressor stations, um + + align:start position:0% +facilities, compressor stations, um + + + align:start position:0% +facilities, compressor stations, um +processing stations, LG terminals, + + align:start position:0% +processing stations, LG terminals, + + + align:start position:0% +processing stations, LG terminals, +whatever else it is that is in between a + + align:start position:0% +whatever else it is that is in between a + + + align:start position:0% +whatever else it is that is in between a +well and your stove or your furnace. And + + align:start position:0% +well and your stove or your furnace. And + + + align:start position:0% +well and your stove or your furnace. And +uh we take our little hazmat placard and + + align:start position:0% +uh we take our little hazmat placard and + + + align:start position:0% +uh we take our little hazmat placard and +say, okay, how bad is all this anyway? + + align:start position:0% +say, okay, how bad is all this anyway? + + + align:start position:0% +say, okay, how bad is all this anyway? +Um + + align:start position:0% +Um + + + align:start position:0% +Um +and I'll argue to you that uh there are + + align:start position:0% +and I'll argue to you that uh there are + + + align:start position:0% +and I'll argue to you that uh there are +hazards present across the entire supply + + align:start position:0% +hazards present across the entire supply + + + align:start position:0% +hazards present across the entire supply +chain. Um we know very little about most + + align:start position:0% +chain. Um we know very little about most + + + align:start position:0% +chain. Um we know very little about most +of these. Um which is, you know, this + + align:start position:0% +of these. Um which is, you know, this + + + align:start position:0% +of these. Um which is, you know, this +could potentially be my whole research + + align:start position:0% +could potentially be my whole research + + + align:start position:0% +could potentially be my whole research +career as a public health professional. + + align:start position:0% +career as a public health professional. + + + align:start position:0% +career as a public health professional. +Um and but uh I'm going to talk in + + align:start position:0% +Um and but uh I'm going to talk in + + + align:start position:0% +Um and but uh I'm going to talk in +detail about a couple of these different + + align:start position:0% +detail about a couple of these different + + + align:start position:0% +detail about a couple of these different +end points just to explain that um what + + align:start position:0% +end points just to explain that um what + + + align:start position:0% +end points just to explain that um what +you all are doing like you know all + + align:start position:0% +you all are doing like you know all + + + align:start position:0% +you all are doing like you know all +about the climate hazards. Um you're + + align:start position:0% +about the climate hazards. Um you're + + + align:start position:0% +about the climate hazards. Um you're +also doing a lot for uh for public + + align:start position:0% +also doing a lot for uh for public + + + align:start position:0% +also doing a lot for uh for public +health. So I'm going to start on the + + align:start position:0% +health. So I'm going to start on the + + + align:start position:0% +health. So I'm going to start on the +production side of things. Uh this is a + + align:start position:0% +production side of things. Uh this is a + + + align:start position:0% +production side of things. Uh this is a +map of every single uh oil and gas well + + align:start position:0% +map of every single uh oil and gas well + + + align:start position:0% +map of every single uh oil and gas well +in the United States. Um you may have + + align:start position:0% +in the United States. Um you may have + + + align:start position:0% +in the United States. Um you may have +noticed that there's a lot of them. Um, + + align:start position:0% +noticed that there's a lot of them. Um, + + + align:start position:0% +noticed that there's a lot of them. Um, +and a natural question that you should + + align:start position:0% +and a natural question that you should + + + align:start position:0% +and a natural question that you should +be asking yourself is, okay, so how big + + align:start position:0% +be asking yourself is, okay, so how big + + + align:start position:0% +be asking yourself is, okay, so how big +of a deal is this really? Um, going + + align:start position:0% +of a deal is this really? Um, going + + + align:start position:0% +of a deal is this really? Um, going +through a hazard assessment, there's + + align:start position:0% +through a hazard assessment, there's + + + align:start position:0% +through a hazard assessment, there's +like a lot of things that could be you + + align:start position:0% +like a lot of things that could be you + + + align:start position:0% +like a lot of things that could be you +could potentially be exposed to. Um, + + align:start position:0% +could potentially be exposed to. Um, + + + align:start position:0% +could potentially be exposed to. Um, +being I mostly focus on sort of regional + + align:start position:0% +being I mostly focus on sort of regional + + + align:start position:0% +being I mostly focus on sort of regional +air pollution. Um so I did a study that + + align:start position:0% +air pollution. Um so I did a study that + + + align:start position:0% +air pollution. Um so I did a study that +was focusing on the regional air + + align:start position:0% +was focusing on the regional air + + + align:start position:0% +was focusing on the regional air +pollution aspects of this and basically + + align:start position:0% +pollution aspects of this and basically + + + align:start position:0% +pollution aspects of this and basically +found that there are um a lot of uh + + align:start position:0% +found that there are um a lot of uh + + + align:start position:0% +found that there are um a lot of uh +violations of the national ambient air + + align:start position:0% +violations of the national ambient air + + + align:start position:0% +violations of the national ambient air +quality standards in the US that are due + + align:start position:0% +quality standards in the US that are due + + + align:start position:0% +quality standards in the US that are due +to the air pollution from oil and gas + + align:start position:0% +to the air pollution from oil and gas + + + align:start position:0% +to the air pollution from oil and gas +extraction. Um there's a big kind of + + align:start position:0% +extraction. Um there's a big kind of + + + align:start position:0% +extraction. Um there's a big kind of +plume of ozone in the middle of the + + align:start position:0% +plume of ozone in the middle of the + + + align:start position:0% +plume of ozone in the middle of the +country over the oil and gas um + + align:start position:0% +country over the oil and gas um + + + align:start position:0% +country over the oil and gas um +production there. Um there's NO2 which + + align:start position:0% +production there. Um there's NO2 which + + + align:start position:0% +production there. Um there's NO2 which +we're concerned about from a respiratory + + align:start position:0% +we're concerned about from a respiratory + + + align:start position:0% +we're concerned about from a respiratory +health standpoint. um this tends to be + + align:start position:0% +health standpoint. um this tends to be + + + align:start position:0% +health standpoint. um this tends to be +more concentrated in production areas + + align:start position:0% +more concentrated in production areas + + + align:start position:0% +more concentrated in production areas +and then PM2.5 which is our standard um + + align:start position:0% +and then PM2.5 which is our standard um + + + align:start position:0% +and then PM2.5 which is our standard um +aerosol um somewhere in between. So + + align:start position:0% +aerosol um somewhere in between. So + + + align:start position:0% +aerosol um somewhere in between. So +that's great. Um and then running it + + align:start position:0% +that's great. Um and then running it + + + align:start position:0% +that's great. Um and then running it +running it through all the science that + + align:start position:0% +running it through all the science that + + + align:start position:0% +running it through all the science that +we have about who lives where and what + + align:start position:0% +we have about who lives where and what + + + align:start position:0% +we have about who lives where and what +the health impacts of these different + + align:start position:0% +the health impacts of these different + + + align:start position:0% +the health impacts of these different +pollutants are. Um we have about 7,500 + + align:start position:0% +pollutants are. Um we have about 7,500 + + + align:start position:0% +pollutants are. Um we have about 7,500 +deaths per year in the United States due + + align:start position:0% +deaths per year in the United States due + + + align:start position:0% +deaths per year in the United States due +to air pollution from oil and gas + + align:start position:0% +to air pollution from oil and gas + + + align:start position:0% +to air pollution from oil and gas +production. um about 410,000 asthma + + align:start position:0% +production. um about 410,000 asthma + + + align:start position:0% +production. um about 410,000 asthma +attacks and 220 uh these are children + + align:start position:0% +attacks and 220 uh these are children + + + align:start position:0% +attacks and 220 uh these are children +that are newly diagnosed with asthma per + + align:start position:0% +that are newly diagnosed with asthma per + + + align:start position:0% +that are newly diagnosed with asthma per +year due to oil and gas just the + + align:start position:0% +year due to oil and gas just the + + + align:start position:0% +year due to oil and gas just the +production side pollution in the US. Um + + align:start position:0% +production side pollution in the US. Um + + + align:start position:0% +production side pollution in the US. Um +so toting up all the health damages um + + align:start position:0% +so toting up all the health damages um + + + align:start position:0% +so toting up all the health damages um +on top of this there's like emergency + + align:start position:0% +on top of this there's like emergency + + + align:start position:0% +on top of this there's like emergency +department visits, hospitalizations, + + align:start position:0% +department visits, hospitalizations, + + + align:start position:0% +department visits, hospitalizations, +heart attacks, strokes um a whole + + align:start position:0% +heart attacks, strokes um a whole + + + align:start position:0% +heart attacks, strokes um a whole +growing menu of health outcomes that are + + align:start position:0% +growing menu of health outcomes that are + + + align:start position:0% +growing menu of health outcomes that are +related to um air pollution. And uh we + + align:start position:0% +related to um air pollution. And uh we + + + align:start position:0% +related to um air pollution. And uh we +can put a price tag on this of about 77 + + align:start position:0% +can put a price tag on this of about 77 + + + align:start position:0% +can put a price tag on this of about 77 +billion with a B dollars yearly due to + + align:start position:0% +billion with a B dollars yearly due to + + + align:start position:0% +billion with a B dollars yearly due to +production of oil and gas. Um and as + + align:start position:0% +production of oil and gas. Um and as + + + align:start position:0% +production of oil and gas. Um and as +you've heard um geothermal will be able + + align:start position:0% +you've heard um geothermal will be able + + + align:start position:0% +you've heard um geothermal will be able +to kind of put a dent in that. So that's + + align:start position:0% +to kind of put a dent in that. So that's + + + align:start position:0% +to kind of put a dent in that. So that's +just the production side. Um and I'm + + align:start position:0% +just the production side. Um and I'm + + + align:start position:0% +just the production side. Um and I'm +going to move over to the other end of + + align:start position:0% +going to move over to the other end of + + + align:start position:0% +going to move over to the other end of +this which is the stove. Um they do emit + + align:start position:0% +this which is the stove. Um they do emit + + + align:start position:0% +this which is the stove. Um they do emit +air pollution. Um there's benzene which + + align:start position:0% +air pollution. Um there's benzene which + + + align:start position:0% +air pollution. Um there's benzene which +is a carcinogen so it causes cancer. + + align:start position:0% +is a carcinogen so it causes cancer. + + + align:start position:0% +is a carcinogen so it causes cancer. +There's a whole lot of volatile organic + + align:start position:0% +There's a whole lot of volatile organic + + + align:start position:0% +There's a whole lot of volatile organic +compounds that come along with that. + + align:start position:0% +compounds that come along with that. + + + align:start position:0% +compounds that come along with that. +there's NO2 when you burn it again and + + align:start position:0% +there's NO2 when you burn it again and + + + align:start position:0% +there's NO2 when you burn it again and +methane which is the greenhouse gas that + + align:start position:0% +methane which is the greenhouse gas that + + + align:start position:0% +methane which is the greenhouse gas that +we're all worried about from a climate + + align:start position:0% +we're all worried about from a climate + + + align:start position:0% +we're all worried about from a climate +standpoint. Um so Zand, myself and maybe + + align:start position:0% +standpoint. Um so Zand, myself and maybe + + + align:start position:0% +standpoint. Um so Zand, myself and maybe +a few other people in the room, Nathan + + align:start position:0% +a few other people in the room, Nathan + + + align:start position:0% +a few other people in the room, Nathan +um were involved in a study that um + + align:start position:0% +um were involved in a study that um + + + align:start position:0% +um were involved in a study that um +basically sampled gas around Boston. So + + align:start position:0% +basically sampled gas around Boston. So + + + align:start position:0% +basically sampled gas around Boston. So +we put it in a canister, sent it to a + + align:start position:0% +we put it in a canister, sent it to a + + + align:start position:0% +we put it in a canister, sent it to a +lab and they told us what was in it. Um + + align:start position:0% +lab and they told us what was in it. Um + + + align:start position:0% +lab and they told us what was in it. Um +and uh it looked like an organic + + align:start position:0% +and uh it looked like an organic + + + align:start position:0% +and uh it looked like an organic +chemistry textbook. Um there was uh a + + align:start position:0% +chemistry textbook. Um there was uh a + + + align:start position:0% +chemistry textbook. Um there was uh a +lot of methane as expected, a lot of + + align:start position:0% +lot of methane as expected, a lot of + + + align:start position:0% +lot of methane as expected, a lot of +ethane as expected, but a whole lot of + + align:start position:0% +ethane as expected, but a whole lot of + + + align:start position:0% +ethane as expected, but a whole lot of +things that were not methane and they + + align:start position:0% +things that were not methane and they + + + align:start position:0% +things that were not methane and they +were not ethane. Um we got hexane, + + align:start position:0% +were not ethane. Um we got hexane, + + + align:start position:0% +were not ethane. Um we got hexane, +benzene, taluine and heptine, + + align:start position:0% +benzene, taluine and heptine, + + + align:start position:0% +benzene, taluine and heptine, +carcinogenic, uh MPY, carcinogenic, + + align:start position:0% +carcinogenic, uh MPY, carcinogenic, + + + align:start position:0% +carcinogenic, uh MPY, carcinogenic, +carcinogenic xylene, and then all these + + align:start position:0% +carcinogenic xylene, and then all these + + + align:start position:0% +carcinogenic xylene, and then all these +other things that are also uh + + align:start position:0% +other things that are also uh + + + align:start position:0% +other things that are also uh +carcinogenic. Um so they went on to keep + + align:start position:0% +carcinogenic. Um so they went on to keep + + + align:start position:0% +carcinogenic. Um so they went on to keep +doing this kind of research. Uh turns + + align:start position:0% +doing this kind of research. Uh turns + + + align:start position:0% +doing this kind of research. Uh turns +out that Boston is not the only place + + align:start position:0% +out that Boston is not the only place + + + align:start position:0% +out that Boston is not the only place +that has a problem. Um it's uh there's + + align:start position:0% +that has a problem. Um it's uh there's + + + align:start position:0% +that has a problem. Um it's uh there's +also issues related to these odorants um + + align:start position:0% +also issues related to these odorants um + + + align:start position:0% +also issues related to these odorants um +which is the chemical that is uh + + align:start position:0% +which is the chemical that is uh + + + align:start position:0% +which is the chemical that is uh +intentionally added to the gas stream so + + align:start position:0% +intentionally added to the gas stream so + + + align:start position:0% +intentionally added to the gas stream so +we can smell it when it leaks. Um turns + + align:start position:0% +we can smell it when it leaks. Um turns + + + align:start position:0% +we can smell it when it leaks. Um turns +out that humans don't like how it smells + + align:start position:0% +out that humans don't like how it smells + + + align:start position:0% +out that humans don't like how it smells +because it is a respiratory irritant. + + align:start position:0% +because it is a respiratory irritant. + + + align:start position:0% +because it is a respiratory irritant. +It's harmful. Um and potentially there's + + align:start position:0% +It's harmful. Um and potentially there's + + + align:start position:0% +It's harmful. Um and potentially there's +other health issues related to it. Um + + align:start position:0% +other health issues related to it. Um + + + align:start position:0% +other health issues related to it. Um +but it is uh present in all the gas + + align:start position:0% +but it is uh present in all the gas + + + align:start position:0% +but it is uh present in all the gas +everywhere. Um and again looking at just + + align:start position:0% +everywhere. Um and again looking at just + + + align:start position:0% +everywhere. Um and again looking at just +benzene again um basically every single + + align:start position:0% +benzene again um basically every single + + + align:start position:0% +benzene again um basically every single +canister they sent to a lab had some + + align:start position:0% +canister they sent to a lab had some + + + align:start position:0% +canister they sent to a lab had some +amount of benzene in it. Um Boston is + + align:start position:0% +amount of benzene in it. Um Boston is + + + align:start position:0% +amount of benzene in it. Um Boston is +actually on the lowest end of the + + align:start position:0% +actually on the lowest end of the + + + align:start position:0% +actually on the lowest end of the +spectrum as far as um benzene + + align:start position:0% +spectrum as far as um benzene + + + align:start position:0% +spectrum as far as um benzene +concentrations. The highest in the US is + + align:start position:0% +concentrations. The highest in the US is + + + align:start position:0% +concentrations. The highest in the US is +Los Angeles and the highest of places in + + align:start position:0% +Los Angeles and the highest of places in + + + align:start position:0% +Los Angeles and the highest of places in +the uh in North America that they + + align:start position:0% +the uh in North America that they + + + align:start position:0% +the uh in North America that they +sampled was uh Vancouver and Los + + align:start position:0% +sampled was uh Vancouver and Los + + + align:start position:0% +sampled was uh Vancouver and Los +Angeles. So, um, + + align:start position:0% +Angeles. So, um, + + + align:start position:0% +Angeles. So, um, +you know, I could go on for hours about + + align:start position:0% +you know, I could go on for hours about + + + align:start position:0% +you know, I could go on for hours about +every single one of these spots, but, + + align:start position:0% +every single one of these spots, but, + + + align:start position:0% +every single one of these spots, but, +um, I I just wanted to give folks kind + + align:start position:0% +um, I I just wanted to give folks kind + + + align:start position:0% +um, I I just wanted to give folks kind +of a small snapshot of the types of + + align:start position:0% +of a small snapshot of the types of + + + align:start position:0% +of a small snapshot of the types of +health hazards that you all are helping + + align:start position:0% +health hazards that you all are helping + + + align:start position:0% +health hazards that you all are helping +to prevent by switching over to + + align:start position:0% +to prevent by switching over to + + + align:start position:0% +to prevent by switching over to +geothermal. Um because if you uh change + + align:start position:0% +geothermal. Um because if you uh change + + + align:start position:0% +geothermal. Um because if you uh change +what's going on on the right side of the + + align:start position:0% +what's going on on the right side of the + + + align:start position:0% +what's going on on the right side of the +supply chain, you're having ripple + + align:start position:0% +supply chain, you're having ripple + + + align:start position:0% +supply chain, you're having ripple +effects all the way across the supply + + align:start position:0% +effects all the way across the supply + + + align:start position:0% +effects all the way across the supply +chain and reducing air pollution, + + align:start position:0% +chain and reducing air pollution, + + + align:start position:0% +chain and reducing air pollution, +reducing safety hazards due to gas + + align:start position:0% +reducing safety hazards due to gas + + + align:start position:0% +reducing safety hazards due to gas +storage, which I could talk for hours + + align:start position:0% +storage, which I could talk for hours + + + align:start position:0% +storage, which I could talk for hours +about. Um reducing use of pipelines, + + align:start position:0% +about. Um reducing use of pipelines, + + + align:start position:0% +about. Um reducing use of pipelines, +reducing compressor station pollution, + + align:start position:0% +reducing compressor station pollution, + + + align:start position:0% +reducing compressor station pollution, +um and you know, really being a public + + align:start position:0% +um and you know, really being a public + + + align:start position:0% +um and you know, really being a public +health resource. So that's it. + + align:start position:0% + + + + align:start position:0% + +>> Thank you so much. I am feeling really + + align:start position:0% +>> Thank you so much. I am feeling really + + + align:start position:0% +>> Thank you so much. I am feeling really +grateful for those three amazing talks + + align:start position:0% +grateful for those three amazing talks + + + align:start position:0% +grateful for those three amazing talks +to start our day. \ No newline at end of file diff --git a/e10dswn-grA.txt b/e10dswn-grA.txt new file mode 100644 index 0000000000000000000000000000000000000000..31cc6bea7cc318448536f61be2fdcdff87222347 --- /dev/null +++ b/e10dswn-grA.txt @@ -0,0 +1,16097 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT open courseware continue + + align:start position:0% +will help MIT open courseware continue + + + align:start position:0% +will help MIT open courseware continue +to offer highquality educational + + align:start position:0% +to offer highquality educational + + + align:start position:0% +to offer highquality educational +resources for free to make a donation or + + align:start position:0% +resources for free to make a donation or + + + align:start position:0% +resources for free to make a donation or +to view additional materials from + + align:start position:0% +to view additional materials from + + + align:start position:0% +to view additional materials from +hundreds of MIT courses visit MIT open + + align:start position:0% +hundreds of MIT courses visit MIT open + + + align:start position:0% +hundreds of MIT courses visit MIT open +courseware at + + align:start position:0% + + + + align:start position:0% + +ocw.mit.edu welcome back to 6890 uh + + align:start position:0% +ocw.mit.edu welcome back to 6890 uh + + + align:start position:0% +ocw.mit.edu welcome back to 6890 uh +today we will do many more hardness + + align:start position:0% +today we will do many more hardness + + + align:start position:0% +today we will do many more hardness +proofs uh mostly of games and puzzles uh + + align:start position:0% +proofs uh mostly of games and puzzles uh + + + align:start position:0% +proofs uh mostly of games and puzzles uh +and some graph theoretic problems uh all + + align:start position:0% +and some graph theoretic problems uh all + + + align:start position:0% +and some graph theoretic problems uh all +reducing from three Set uh we're going + + align:start position:0% +reducing from three Set uh we're going + + + align:start position:0% +reducing from three Set uh we're going +to continue where we left off last time + + align:start position:0% +to continue where we left off last time + + + align:start position:0% +to continue where we left off last time +which was with this picture which also + + align:start position:0% +which was with this picture which also + + + align:start position:0% +which was with this picture which also +comes from lecture one uh which is how + + align:start position:0% +comes from lecture one uh which is how + + + align:start position:0% +comes from lecture one uh which is how +to prove Super Mario Brothers is NP hard + + align:start position:0% +to prove Super Mario Brothers is NP hard + + + align:start position:0% +to prove Super Mario Brothers is NP hard +we had two main gadgets the variable + + align:start position:0% +we had two main gadgets the variable + + + align:start position:0% +we had two main gadgets the variable +Gadget which uh forces your player to + + align:start position:0% +Gadget which uh forces your player to + + + align:start position:0% +Gadget which uh forces your player to +choose going left or right and the + + align:start position:0% +choose going left or right and the + + + align:start position:0% +choose going left or right and the +Clause Gadget which uh could be visited + + align:start position:0% +Clause Gadget which uh could be visited + + + align:start position:0% +Clause Gadget which uh could be visited +in three three different ways in order + + align:start position:0% +in three three different ways in order + + + align:start position:0% +in three three different ways in order +to enable it these each contained an + + align:start position:0% +to enable it these each contained an + + + align:start position:0% +to enable it these each contained an +invincibility star so if later you come + + align:start position:0% +invincibility star so if later you come + + + align:start position:0% +invincibility star so if later you come +through to Traverse the gadget you can + + align:start position:0% +through to Traverse the gadget you can + + + align:start position:0% +through to Traverse the gadget you can +get through all these fireb bars if and + + align:start position:0% +get through all these fireb bars if and + + + align:start position:0% +get through all these fireb bars if and +only if there was at least one star + + align:start position:0% +only if there was at least one star + + + align:start position:0% +only if there was at least one star +there so that was a regular three set + + align:start position:0% +there so that was a regular three set + + + align:start position:0% +there so that was a regular three set +clause and then there's the connectivity + + align:start position:0% +clause and then there's the connectivity + + + align:start position:0% +clause and then there's the connectivity +in between and so in particular you need + + align:start position:0% +in between and so in particular you need + + + align:start position:0% +in between and so in particular you need +a crossover Gadget with this setup but + + align:start position:0% +a crossover Gadget with this setup but + + + align:start position:0% +a crossover Gadget with this setup but +the general idea is you visit variable + + align:start position:0% +the general idea is you visit variable + + + align:start position:0% +the general idea is you visit variable +visit all the Clauses that are in it uh + + align:start position:0% +visit all the Clauses that are in it uh + + + align:start position:0% +visit all the Clauses that are in it uh +that include that literal the one you + + align:start position:0% +that include that literal the one you + + + align:start position:0% +that include that literal the one you +you get to choose only one then you go + + align:start position:0% +you get to choose only one then you go + + + align:start position:0% +you get to choose only one then you go +to the next variable next variable and + + align:start position:0% +to the next variable next variable and + + + align:start position:0% +to the next variable next variable and +then you Trav all the Clauses that you + + align:start position:0% +then you Trav all the Clauses that you + + + align:start position:0% +then you Trav all the Clauses that you +can get to finish if and only if uh the + + align:start position:0% +can get to finish if and only if uh the + + + align:start position:0% +can get to finish if and only if uh the +three step formula was satisfiable this + + align:start position:0% +three step formula was satisfiable this + + + align:start position:0% +three step formula was satisfiable this +is a general uh construction or approach + + align:start position:0% +is a general uh construction or approach + + + align:start position:0% +is a general uh construction or approach +for platform video games that's what we + + align:start position:0% +for platform video games that's what we + + + align:start position:0% +for platform video games that's what we +uh were presenting it as in a recent + + align:start position:0% +uh were presenting it as in a recent + + + align:start position:0% +uh were presenting it as in a recent +paper uh I thought I'd show you a few + + align:start position:0% +paper uh I thought I'd show you a few + + + align:start position:0% +paper uh I thought I'd show you a few +other uh Nintendo games you can prove + + align:start position:0% +other uh Nintendo games you can prove + + + align:start position:0% +other uh Nintendo games you can prove +hard with this technique uh this is the + + align:start position:0% +hard with this technique uh this is the + + + align:start position:0% +hard with this technique uh this is the +Clause gadget for Super Mario World uh + + align:start position:0% +Clause gadget for Super Mario World uh + + + align:start position:0% +Clause gadget for Super Mario World uh +so in Super Mario World there are these + + align:start position:0% +so in Super Mario World there are these + + + align:start position:0% +so in Super Mario World there are these +great uh question mark blocks and in + + align:start position:0% +great uh question mark blocks and in + + + align:start position:0% +great uh question mark blocks and in +particular uh pow blocks which go back + + align:start position:0% +particular uh pow blocks which go back + + + align:start position:0% +particular uh pow blocks which go back +to the original uh Mario Brothers + + align:start position:0% +to the original uh Mario Brothers + + + align:start position:0% +to the original uh Mario Brothers +without the super how many people played + + align:start position:0% +without the super how many people played + + + align:start position:0% +without the super how many people played +Mario Brothers kind of old really old + + align:start position:0% +Mario Brothers kind of old really old + + + align:start position:0% +Mario Brothers kind of old really old +school pre Super Mario and uh anyway it + + align:start position:0% +school pre Super Mario and uh anyway it + + + align:start position:0% +school pre Super Mario and uh anyway it +doesn't matter exactly where it comes + + align:start position:0% +doesn't matter exactly where it comes + + + align:start position:0% +doesn't matter exactly where it comes +from it does something completely + + align:start position:0% +from it does something completely + + + align:start position:0% +from it does something completely +different in Super Mario World um which + + align:start position:0% +different in Super Mario World um which + + + align:start position:0% +different in Super Mario World um which +is turns all coins into walkable things + + align:start position:0% +is turns all coins into walkable things + + + align:start position:0% +is turns all coins into walkable things +you can walk on for like 10 seconds uh + + align:start position:0% +you can walk on for like 10 seconds uh + + + align:start position:0% +you can walk on for like 10 seconds uh +but you can't normally hit a question + + align:start position:0% +but you can't normally hit a question + + + align:start position:0% +but you can't normally hit a question +mark block except from the bottom + + align:start position:0% +mark block except from the bottom + + + align:start position:0% +mark block except from the bottom +there's no way to do that here but if + + align:start position:0% +there's no way to do that here but if + + + align:start position:0% +there's no way to do that here but if +you can visit one of these three places + + align:start position:0% +you can visit one of these three places + + + align:start position:0% +you can visit one of these three places +you can send one of these turtle shells + + align:start position:0% +you can send one of these turtle shells + + + align:start position:0% +you can send one of these turtle shells +flying and it will hit this and bring + + align:start position:0% +flying and it will hit this and bring + + + align:start position:0% +flying and it will hit this and bring +the PO block off and then disappear so + + align:start position:0% +the PO block off and then disappear so + + + align:start position:0% +the PO block off and then disappear so +that later when you try to Traverse this + + align:start position:0% +that later when you try to Traverse this + + + align:start position:0% +that later when you try to Traverse this +Clause Gadget if there's a PO block you + + align:start position:0% +Clause Gadget if there's a PO block you + + + align:start position:0% +Clause Gadget if there's a PO block you +can turn these into Sol solid things for + + align:start position:0% +can turn these into Sol solid things for + + + align:start position:0% +can turn these into Sol solid things for +long enough you can get a cross but no + + align:start position:0% +long enough you can get a cross but no + + + align:start position:0% +long enough you can get a cross but no +longer than that so in the next Gadget + + align:start position:0% +longer than that so in the next Gadget + + + align:start position:0% +longer than that so in the next Gadget +you need another po block and so on so + + align:start position:0% +you need another po block and so on so + + + align:start position:0% +you need another po block and so on so +that's Claus gadget for Super Mario + + align:start position:0% +that's Claus gadget for Super Mario + + + align:start position:0% +that's Claus gadget for Super Mario +World um the other gadgets are pretty + + align:start position:0% +World um the other gadgets are pretty + + + align:start position:0% +World um the other gadgets are pretty +similar so I'll just show you that one + + align:start position:0% +similar so I'll just show you that one + + + align:start position:0% +similar so I'll just show you that one +does the Star Trek not work uh + + align:start position:0% +does the Star Trek not work uh + + + align:start position:0% +does the Star Trek not work uh +I guess you could also do the Star trick + + align:start position:0% +I guess you could also do the Star trick + + + align:start position:0% +I guess you could also do the Star trick +but I think we drew this figure before + + align:start position:0% +but I think we drew this figure before + + + align:start position:0% +but I think we drew this figure before +we did the Star trick so we thought oh + + align:start position:0% +we did the Star trick so we thought oh + + + align:start position:0% +we did the Star trick so we thought oh +this is + + align:start position:0% +this is + + + align:start position:0% +this is +cooler + + align:start position:0% +cooler + + + align:start position:0% +cooler +yeah um now one thing I I thought I'd + + align:start position:0% +yeah um now one thing I I thought I'd + + + align:start position:0% +yeah um now one thing I I thought I'd +mention uh briefly is uh some fun + + align:start position:0% +mention uh briefly is uh some fun + + + align:start position:0% +mention uh briefly is uh some fun +glitches you can do in real Super Mario + + align:start position:0% +glitches you can do in real Super Mario + + + align:start position:0% +glitches you can do in real Super Mario +Brothers as implemented on the ROMs um + + align:start position:0% +Brothers as implemented on the ROMs um + + + align:start position:0% +Brothers as implemented on the ROMs um +you can do these crazy things like jump + + align:start position:0% +you can do these crazy things like jump + + + align:start position:0% +you can do these crazy things like jump +off of walls you're not supposed to be + + align:start position:0% +off of walls you're not supposed to be + + + align:start position:0% +off of walls you're not supposed to be +able to do this and this level would be + + align:start position:0% +able to do this and this level would be + + + align:start position:0% +able to do this and this level would be +unsolvable in the way you normally think + + align:start position:0% +unsolvable in the way you normally think + + + align:start position:0% +unsolvable in the way you normally think +about uh Super Mario Brothers but there + + align:start position:0% +about uh Super Mario Brothers but there + + + align:start position:0% +about uh Super Mario Brothers but there +happens to be this fun sub pixel + + align:start position:0% +happens to be this fun sub pixel + + + align:start position:0% +happens to be this fun sub pixel +resolution I think this is usually done + + align:start position:0% +resolution I think this is usually done + + + align:start position:0% +resolution I think this is usually done +very hard to do with a real controller + + align:start position:0% +very hard to do with a real controller + + + align:start position:0% +very hard to do with a real controller +but much easier to do when you can slow + + align:start position:0% +but much easier to do when you can slow + + + align:start position:0% +but much easier to do when you can slow +things down a 100 times and every frame + + align:start position:0% +things down a 100 times and every frame + + + align:start position:0% +things down a 100 times and every frame +you have a choice of whether to push a + + align:start position:0% +you have a choice of whether to push a + + + align:start position:0% +you have a choice of whether to push a +particular button that's called to Tool + + align:start position:0% +particular button that's called to Tool + + + align:start position:0% +particular button that's called to Tool +assisted speedruns usually um and so you + + align:start position:0% +assisted speedruns usually um and so you + + + align:start position:0% +assisted speedruns usually um and so you +might I don't know if you consider this + + align:start position:0% +might I don't know if you consider this + + + align:start position:0% +might I don't know if you consider this +real Super Mario Brothers or not it + + align:start position:0% +real Super Mario Brothers or not it + + + align:start position:0% +real Super Mario Brothers or not it +depends on your notion of reality + + align:start position:0% +depends on your notion of reality + + + align:start position:0% +depends on your notion of reality +whether you more a mathematician or a + + align:start position:0% +whether you more a mathematician or a + + + align:start position:0% +whether you more a mathematician or a +gamer I guess uh but you can try to + + align:start position:0% +gamer I guess uh but you can try to + + + align:start position:0% +gamer I guess uh but you can try to +modify the gadgets so that uh wall + + align:start position:0% +modify the gadgets so that uh wall + + + align:start position:0% +modify the gadgets so that uh wall +jumping doesn't help you uh so you could + + align:start position:0% +jumping doesn't help you uh so you could + + + align:start position:0% +jumping doesn't help you uh so you could +imagine trying to jump up these walls + + align:start position:0% +imagine trying to jump up these walls + + + align:start position:0% +imagine trying to jump up these walls +but if there's things in the way + + align:start position:0% +but if there's things in the way + + + align:start position:0% +but if there's things in the way +prevents it so if you just add that to + + align:start position:0% +prevents it so if you just add that to + + + align:start position:0% +prevents it so if you just add that to +every vertical tunnel that will uh + + align:start position:0% +every vertical tunnel that will uh + + + align:start position:0% +every vertical tunnel that will uh +prevent going back up the tunnels which + + align:start position:0% +prevent going back up the tunnels which + + + align:start position:0% +prevent going back up the tunnels which +is important for the variable gadgets we + + align:start position:0% +is important for the variable gadgets we + + + align:start position:0% +is important for the variable gadgets we +don't want to be able to reverse our + + align:start position:0% +don't want to be able to reverse our + + + align:start position:0% +don't want to be able to reverse our +decision and later choose the opposite + + align:start position:0% +decision and later choose the opposite + + + align:start position:0% +decision and later choose the opposite +variable setting here's another fun set + + align:start position:0% +variable setting here's another fun set + + + align:start position:0% +variable setting here's another fun set +of uh um cheats where you you jump + + align:start position:0% +of uh um cheats where you you jump + + + align:start position:0% +of uh um cheats where you you jump +through the walls this one is apparently + + align:start position:0% +through the walls this one is apparently + + + align:start position:0% +through the walls this one is apparently +somewhat doable on a real controller uh + + align:start position:0% +somewhat doable on a real controller uh + + + align:start position:0% +somewhat doable on a real controller uh +but still quite challenging um I think + + align:start position:0% +but still quite challenging um I think + + + align:start position:0% +but still quite challenging um I think +the one of the general ideas is the + + align:start position:0% +the one of the general ideas is the + + + align:start position:0% +the one of the general ideas is the +Collision detection is not super good in + + align:start position:0% +Collision detection is not super good in + + + align:start position:0% +Collision detection is not super good in +the game as implemented uh so if you + + align:start position:0% +the game as implemented uh so if you + + + align:start position:0% +the game as implemented uh so if you +time if you get just the right geometry + + align:start position:0% +time if you get just the right geometry + + + align:start position:0% +time if you get just the right geometry +you can walk through the walls there's + + align:start position:0% +you can walk through the walls there's + + + align:start position:0% +you can walk through the walls there's +instructions + + align:start position:0% +instructions + + + align:start position:0% +instructions +for um so this is obviously problematic + + align:start position:0% +for um so this is obviously problematic + + + align:start position:0% +for um so this is obviously problematic +because all of our gadgets involve walls + + align:start position:0% +because all of our gadgets involve walls + + + align:start position:0% +because all of our gadgets involve walls +so if you can walk through them + + align:start position:0% +so if you can walk through them + + + align:start position:0% +so if you can walk through them +not very uh interesting so a general + + align:start position:0% +not very uh interesting so a general + + + align:start position:0% +not very uh interesting so a general +approach is to just add lots of + + align:start position:0% +approach is to just add lots of + + + align:start position:0% +approach is to just add lots of +monsters into the walls so even if you + + align:start position:0% +monsters into the walls so even if you + + + align:start position:0% +monsters into the walls so even if you +could walk through you become small + + align:start position:0% +could walk through you become small + + + align:start position:0% +could walk through you become small +Mario and then that's not an option um I + + align:start position:0% +Mario and then that's not an option um I + + + align:start position:0% +Mario and then that's not an option um I +should say these have not been + + align:start position:0% +should say these have not been + + + align:start position:0% +should say these have not been +thoroughly tested so it's plausible you + + align:start position:0% +thoroughly tested so it's plausible you + + + align:start position:0% +thoroughly tested so it's plausible you +can walk through the wall in such a way + + align:start position:0% +can walk through the wall in such a way + + + align:start position:0% +can walk through the wall in such a way +that maybe you kill the monster or there + + align:start position:0% +that maybe you kill the monster or there + + + align:start position:0% +that maybe you kill the monster or there +may be other glitches that we don't know + + align:start position:0% +may be other glitches that we don't know + + + align:start position:0% +may be other glitches that we don't know +about and so uh you might consider this + + align:start position:0% +about and so uh you might consider this + + + align:start position:0% +about and so uh you might consider this +a work in progress but generally I would + + align:start position:0% +a work in progress but generally I would + + + align:start position:0% +a work in progress but generally I would +believe you can modify the proof to work + + align:start position:0% +believe you can modify the proof to work + + + align:start position:0% +believe you can modify the proof to work +on + + align:start position:0% +on + + + align:start position:0% +on +real Super Mario Brothers as implemented + + align:start position:0% +real Super Mario Brothers as implemented + + + align:start position:0% +real Super Mario Brothers as implemented +in real physics of course generalized to + + align:start position:0% +in real physics of course generalized to + + + align:start position:0% +in real physics of course generalized to +an end byend screen and so on so uh what + + align:start position:0% +an end byend screen and so on so uh what + + + align:start position:0% +an end byend screen and so on so uh what +exactly you call real is uh is + + align:start position:0% +exactly you call real is uh is + + + align:start position:0% +exactly you call real is uh is +challenging there uh but that's Super + + align:start position:0% +challenging there uh but that's Super + + + align:start position:0% +challenging there uh but that's Super +Mario Brothers just uh some more fun + + align:start position:0% +Mario Brothers just uh some more fun + + + align:start position:0% +Mario Brothers just uh some more fun +stuff in the + + align:start position:0% +stuff in the + + + align:start position:0% +stuff in the +paper um let me talk a little bit about + + align:start position:0% +paper um let me talk a little bit about + + + align:start position:0% +paper um let me talk a little bit about +Legend of Zelda uh this is what it looks + + align:start position:0% +Legend of Zelda uh this is what it looks + + + align:start position:0% +Legend of Zelda uh this is what it looks +like in case you've never seen it and uh + + align:start position:0% +like in case you've never seen it and uh + + + align:start position:0% +like in case you've never seen it and uh +this is the original Legend of Zelda + + align:start position:0% +this is the original Legend of Zelda + + + align:start position:0% +this is the original Legend of Zelda +you're a little character you can walk + + align:start position:0% +you're a little character you can walk + + + align:start position:0% +you're a little character you can walk +around and this is what I would say is a + + align:start position:0% +around and this is what I would say is a + + + align:start position:0% +around and this is what I would say is a +typical block pushing puzzle in Legend + + align:start position:0% +typical block pushing puzzle in Legend + + + align:start position:0% +typical block pushing puzzle in Legend +of Sala which is try all the blocks and + + align:start position:0% +of Sala which is try all the blocks and + + + align:start position:0% +of Sala which is try all the blocks and +hope that one of them pushes + + align:start position:0% +hope that one of them pushes + + + align:start position:0% +hope that one of them pushes +and um I I have to say I watched an + + align:start position:0% +and um I I have to say I watched an + + + align:start position:0% +and um I I have to say I watched an +entire I don't know how long it was five + + align:start position:0% +entire I don't know how long it was five + + + align:start position:0% +entire I don't know how long it was five +hours of walk through Legend of Zelda + + align:start position:0% +hours of walk through Legend of Zelda + + + align:start position:0% +hours of walk through Legend of Zelda +one to find whether there are any more + + align:start position:0% +one to find whether there are any more + + + align:start position:0% +one to find whether there are any more +complicated block pushing puzzles I + + align:start position:0% +complicated block pushing puzzles I + + + align:start position:0% +complicated block pushing puzzles I +swear I remember a slightly more + + align:start position:0% +swear I remember a slightly more + + + align:start position:0% +swear I remember a slightly more +complicated one but I could not find it + + align:start position:0% +complicated one but I could not find it + + + align:start position:0% +complicated one but I could not find it +it's possible skipped in this particular + + align:start position:0% +it's possible skipped in this particular + + + align:start position:0% +it's possible skipped in this particular +walkth through um this well okay it just + + align:start position:0% +walkth through um this well okay it just + + + align:start position:0% +walkth through um this well okay it just +takes a long time but you get all right + + align:start position:0% +takes a long time but you get all right + + + align:start position:0% +takes a long time but you get all right +we're almost done you get an idea of how + + align:start position:0% +we're almost done you get an idea of how + + + align:start position:0% +we're almost done you get an idea of how +uh of what the game is like you've got a + + align:start position:0% +uh of what the game is like you've got a + + + align:start position:0% +uh of what the game is like you've got a +sword whatever that won't be + + align:start position:0% +sword whatever that won't be + + + align:start position:0% +sword whatever that won't be +particularly relevant to our reductions + + align:start position:0% +particularly relevant to our reductions + + + align:start position:0% +particularly relevant to our reductions +there will be no monsters in our + + align:start position:0% +there will be no monsters in our + + + align:start position:0% +there will be no monsters in our +reductions in this case I think you just + + align:start position:0% +reductions in this case I think you just + + + align:start position:0% +reductions in this case I think you just +have to wait a really long time or + + align:start position:0% +have to wait a really long time or + + + align:start position:0% +have to wait a really long time or +possibly kill the the hand that comes + + align:start position:0% +possibly kill the the hand that comes + + + align:start position:0% +possibly kill the the hand that comes +out then you can push that block he + + align:start position:0% +out then you can push that block he + + + align:start position:0% +out then you can push that block he +actually tried to push in the beginning + + align:start position:0% +actually tried to push in the beginning + + + align:start position:0% +actually tried to push in the beginning +but it wouldn't move anyway that's + + align:start position:0% +but it wouldn't move anyway that's + + + align:start position:0% +but it wouldn't move anyway that's +Legend of Zelda uh the the uh here's a + + align:start position:0% +Legend of Zelda uh the the uh here's a + + + align:start position:0% +Legend of Zelda uh the the uh here's a +slightly more interesting one this is + + align:start position:0% +slightly more interesting one this is + + + align:start position:0% +slightly more interesting one this is +what I remember normally you push one + + align:start position:0% +what I remember normally you push one + + + align:start position:0% +what I remember normally you push one +two three and then you push this to the + + align:start position:0% +two three and then you push this to the + + + align:start position:0% +two three and then you push this to the +side in this particular particular case + + align:start position:0% +side in this particular particular case + + + align:start position:0% +side in this particular particular case +blocks are not pushable sideways which + + align:start position:0% +blocks are not pushable sideways which + + + align:start position:0% +blocks are not pushable sideways which +is really annoying so you actually have + + align:start position:0% +is really annoying so you actually have + + + align:start position:0% +is really annoying so you actually have +to solve it a different way if you watch + + align:start position:0% +to solve it a different way if you watch + + + align:start position:0% +to solve it a different way if you watch +this video at this point he's like oh my + + align:start position:0% +this video at this point he's like oh my + + + align:start position:0% +this video at this point he's like oh my +God this was the simplest blocking push + + align:start position:0% +God this was the simplest blocking push + + + align:start position:0% +God this was the simplest blocking push +block pushing puzzle ever and I solved + + align:start position:0% +block pushing puzzle ever and I solved + + + align:start position:0% +block pushing puzzle ever and I solved +it + + align:start position:0% +it + + + align:start position:0% +it +yay it's like after half an hour of + + align:start position:0% +yay it's like after half an hour of + + + align:start position:0% +yay it's like after half an hour of +trying other things um that's the the + + align:start position:0% +trying other things um that's the the + + + align:start position:0% +trying other things um that's the the +joy of Legend of Zelda very fun puzzles + + align:start position:0% +joy of Legend of Zelda very fun puzzles + + + align:start position:0% +joy of Legend of Zelda very fun puzzles +so to speak uh so the point is you have + + align:start position:0% +so to speak uh so the point is you have + + + align:start position:0% +so to speak uh so the point is you have +block pushing puzzles we already know uh + + align:start position:0% +block pushing puzzles we already know uh + + + align:start position:0% +block pushing puzzles we already know uh +oh sorry here's one more I guess this + + align:start position:0% +oh sorry here's one more I guess this + + + align:start position:0% +oh sorry here's one more I guess this +these are in Legend of Zelda linked to + + align:start position:0% +these are in Legend of Zelda linked to + + + align:start position:0% +these are in Legend of Zelda linked to +the Past uh so it has a slightly more + + align:start position:0% +the Past uh so it has a slightly more + + + align:start position:0% +the Past uh so it has a slightly more +comp There's an actual slightly + + align:start position:0% +comp There's an actual slightly + + + align:start position:0% +comp There's an actual slightly +non-trivial block pushing puzzle um but + + align:start position:0% +non-trivial block pushing puzzle um but + + + align:start position:0% +non-trivial block pushing puzzle um but +in general we know push one is hard uh + + align:start position:0% +in general we know push one is hard uh + + + align:start position:0% +in general we know push one is hard uh +most versions of Legend of Zelda are + + align:start position:0% +most versions of Legend of Zelda are + + + align:start position:0% +most versions of Legend of Zelda are +slightly more restrictive than uh push + + align:start position:0% +slightly more restrictive than uh push + + + align:start position:0% +slightly more restrictive than uh push +one I would call them push once blocks + + align:start position:0% +one I would call them push once blocks + + + align:start position:0% +one I would call them push once blocks +where uh you can only push one uh at a + + align:start position:0% +where uh you can only push one uh at a + + + align:start position:0% +where uh you can only push one uh at a +time that's your strength but also you + + align:start position:0% +time that's your strength but also you + + + align:start position:0% +time that's your strength but also you +can only push a block once you can never + + align:start position:0% +can only push a block once you can never + + + align:start position:0% +can only push a block once you can never +push it a second time or push it back or + + align:start position:0% +push it a second time or push it back or + + + align:start position:0% +push it a second time or push it back or +do anything like that and uh with some + + align:start position:0% +do anything like that and uh with some + + + align:start position:0% +do anything like that and uh with some +slight this is the gadget we saw before + + align:start position:0% +slight this is the gadget we saw before + + + align:start position:0% +slight this is the gadget we saw before +with some slight tweaks you can make the + + align:start position:0% +with some slight tweaks you can make the + + + align:start position:0% +with some slight tweaks you can make the +lock still work when you only allowed to + + align:start position:0% +lock still work when you only allowed to + + + align:start position:0% +lock still work when you only allowed to +push each block once so um that proves + + align:start position:0% +push each block once so um that proves + + + align:start position:0% +push each block once so um that proves +that most versions of Legends of Zelda + + align:start position:0% +that most versions of Legends of Zelda + + + align:start position:0% +that most versions of Legends of Zelda +are at least MP hard uh because they + + align:start position:0% +are at least MP hard uh because they + + + align:start position:0% +are at least MP hard uh because they +include block pushing um but it would be + + align:start position:0% +include block pushing um but it would be + + + align:start position:0% +include block pushing um but it would be +nice to uh understand other senses in + + align:start position:0% +nice to uh understand other senses in + + + align:start position:0% +nice to uh understand other senses in +which these kinds of games are hard + + align:start position:0% +which these kinds of games are hard + + + align:start position:0% +which these kinds of games are hard +without using block pushing so here's + + align:start position:0% +without using block pushing so here's + + + align:start position:0% +without using block pushing so here's +another feature called the um the hook + + align:start position:0% +another feature called the um the hook + + + align:start position:0% +another feature called the um the hook +shot so you select it then if there's a + + align:start position:0% +shot so you select it then if there's a + + + align:start position:0% +shot so you select it then if there's a +object on the other side you can hook + + align:start position:0% +object on the other side you can hook + + + align:start position:0% +object on the other side you can hook +shot to that side so in you can't walk + + align:start position:0% +shot to that side so in you can't walk + + + align:start position:0% +shot to that side so in you can't walk +over the cavern but you can hook shot + + align:start position:0% +over the cavern but you can hook shot + + + align:start position:0% +over the cavern but you can hook shot +across here here it is again as long as + + align:start position:0% +across here here it is again as long as + + + align:start position:0% +across here here it is again as long as +there's an object over there you can + + align:start position:0% +there's an object over there you can + + + align:start position:0% +there's an object over there you can +also pick up objects and Destroy them uh + + align:start position:0% +also pick up objects and Destroy them uh + + + align:start position:0% +also pick up objects and Destroy them uh +so does that make it hard with no + + align:start position:0% +so does that make it hard with no + + + align:start position:0% +so does that make it hard with no +pushing blocks well little bit of + + align:start position:0% +pushing blocks well little bit of + + + align:start position:0% +pushing blocks well little bit of +pushing blocks here's a simple proof + + align:start position:0% +pushing blocks here's a simple proof + + + align:start position:0% +pushing blocks here's a simple proof +using that uh structure so here's a + + align:start position:0% +using that uh structure so here's a + + + align:start position:0% +using that uh structure so here's a +variable uh you go from top to bottom so + + align:start position:0% +variable uh you go from top to bottom so + + + align:start position:0% +variable uh you go from top to bottom so +you're over here uh treasure chests are + + align:start position:0% +you're over here uh treasure chests are + + + align:start position:0% +you're over here uh treasure chests are +something that you can hook shot onto to + + align:start position:0% +something that you can hook shot onto to + + + align:start position:0% +something that you can hook shot onto to +go over the cavern and here you have a + + align:start position:0% +go over the cavern and here you have a + + + align:start position:0% +go over the cavern and here you have a +choice you can go left or you can go + + align:start position:0% +choice you can go left or you can go + + + align:start position:0% +choice you can go left or you can go +right but then you can't back up because + + align:start position:0% +right but then you can't back up because + + + align:start position:0% +right but then you can't back up because +there's no object here to hook shot onto + + align:start position:0% +there's no object here to hook shot onto + + + align:start position:0% +there's no object here to hook shot onto +you can only do it + + align:start position:0% +you can only do it + + + align:start position:0% +you can only do it +orthogonally um here's a clause if you + + align:start position:0% +orthogonally um here's a clause if you + + + align:start position:0% +orthogonally um here's a clause if you +come down any one of these paths then + + align:start position:0% +come down any one of these paths then + + + align:start position:0% +come down any one of these paths then +you can push this block One Step um and + + align:start position:0% +you can push this block One Step um and + + + align:start position:0% +you can push this block One Step um and +then you'll be able to hook shot from + + align:start position:0% +then you'll be able to hook shot from + + + align:start position:0% +then you'll be able to hook shot from +the right uh to get onto this platform + + align:start position:0% +the right uh to get onto this platform + + + align:start position:0% +the right uh to get onto this platform +and then continue to the left uh and a + + align:start position:0% +and then continue to the left uh and a + + + align:start position:0% +and then continue to the left uh and a +crossover is really easy in this world + + align:start position:0% +crossover is really easy in this world + + + align:start position:0% +crossover is really easy in this world +so this there's you could come up with + + align:start position:0% +so this there's you could come up with + + + align:start position:0% +so this there's you could come up with +lots of different NP hardness proofs so + + align:start position:0% +lots of different NP hardness proofs so + + + align:start position:0% +lots of different NP hardness proofs so +this was a a fun one for a link to the + + align:start position:0% +this was a a fun one for a link to the + + + align:start position:0% +this was a a fun one for a link to the +past which is the first one first game + + align:start position:0% +past which is the first one first game + + + align:start position:0% +past which is the first one first game +that has that hook shot this is Metroid + + align:start position:0% +that has that hook shot this is Metroid + + + align:start position:0% +that has that hook shot this is Metroid +if you've never played most of the time + + align:start position:0% +if you've never played most of the time + + + align:start position:0% +if you've never played most of the time +you spend going up and down elevator + + align:start position:0% +you spend going up and down elevator + + + align:start position:0% +you spend going up and down elevator +shafts and there are these monsters + + align:start position:0% +shafts and there are these monsters + + + align:start position:0% +shafts and there are these monsters +which you can shoot um and then there's + + align:start position:0% +which you can shoot um and then there's + + + align:start position:0% +which you can shoot um and then there's +also this ability to become a one by one + + align:start position:0% +also this ability to become a one by one + + + align:start position:0% +also this ability to become a one by one +block instead of a 2 by one block and + + align:start position:0% +block instead of a 2 by one block and + + + align:start position:0% +block instead of a 2 by one block and +roll through small things when you're in + + align:start position:0% +roll through small things when you're in + + + align:start position:0% +roll through small things when you're in +that position uh in a certain part of + + align:start position:0% +that position uh in a certain part of + + + align:start position:0% +that position uh in a certain part of +the game you're not allowed to shoot + + align:start position:0% +the game you're not allowed to shoot + + + align:start position:0% +the game you're not allowed to shoot +okay so that's the situation we're going + + align:start position:0% +okay so that's the situation we're going + + + align:start position:0% +okay so that's the situation we're going +to imagine um um so here is a clause and + + align:start position:0% +to imagine um um so here is a clause and + + + align:start position:0% +to imagine um um so here is a clause and +a crossover I mean the the variable + + align:start position:0% +a crossover I mean the the variable + + + align:start position:0% +a crossover I mean the the variable +Gadget is the same as Mario you fall + + align:start position:0% +Gadget is the same as Mario you fall + + + align:start position:0% +Gadget is the same as Mario you fall +left or fall right you can't go back up + + align:start position:0% +left or fall right you can't go back up + + + align:start position:0% +left or fall right you can't go back up +uh because you have a limited jump + + align:start position:0% +uh because you have a limited jump + + + align:start position:0% +uh because you have a limited jump +height so let's do the Clause first um + + align:start position:0% +height so let's do the Clause first um + + + align:start position:0% +height so let's do the Clause first um +there are three different ways to visit + + align:start position:0% +there are three different ways to visit + + + align:start position:0% +there are three different ways to visit +it uh when you're setting your variables + + align:start position:0% +it uh when you're setting your variables + + + align:start position:0% +it uh when you're setting your variables +if you can get here you can aim upwards + + align:start position:0% +if you can get here you can aim upwards + + + align:start position:0% +if you can get here you can aim upwards +and just shoot all of these things it + + align:start position:0% +and just shoot all of these things it + + + align:start position:0% +and just shoot all of these things it +would take a few minutes but you get rid + + align:start position:0% +would take a few minutes but you get rid + + + align:start position:0% +would take a few minutes but you get rid +of All These Guys these guys just walk + + align:start position:0% +of All These Guys these guys just walk + + + align:start position:0% +of All These Guys these guys just walk +around + + align:start position:0% +around + + + align:start position:0% +around +constantly and then to Traverse you're + + align:start position:0% +constantly and then to Traverse you're + + + align:start position:0% +constantly and then to Traverse you're +going to be coming through here in ball + + align:start position:0% +going to be coming through here in ball + + + align:start position:0% +going to be coming through here in ball +mode there no way to I guess here you + + align:start position:0% +mode there no way to I guess here you + + + align:start position:0% +mode there no way to I guess here you +could briefly stand up but you can't + + align:start position:0% +could briefly stand up but you can't + + + align:start position:0% +could briefly stand up but you can't +shoot down in original Metroid so you + + align:start position:0% +shoot down in original Metroid so you + + + align:start position:0% +shoot down in original Metroid so you +want to roll over here but you would + + align:start position:0% +want to roll over here but you would + + + align:start position:0% +want to roll over here but you would +take too much damage uh maybe you only + + align:start position:0% +take too much damage uh maybe you only + + + align:start position:0% +take too much damage uh maybe you only +have one hit point left so if there's + + align:start position:0% +have one hit point left so if there's + + + align:start position:0% +have one hit point left so if there's +any of these guys left you have to visit + + align:start position:0% +any of these guys left you have to visit + + + align:start position:0% +any of these guys left you have to visit +at least one of these to kill all the + + align:start position:0% +at least one of these to kill all the + + + align:start position:0% +at least one of these to kill all the +monsters and then get through okay + + align:start position:0% +monsters and then get through okay + + + align:start position:0% +monsters and then get through okay +that's Clause crossover is a little more + + align:start position:0% +that's Clause crossover is a little more + + + align:start position:0% +that's Clause crossover is a little more +challenging um in this case we set + + align:start position:0% +challenging um in this case we set + + + align:start position:0% +challenging um in this case we set +things up the idea is you come in here + + align:start position:0% +things up the idea is you come in here + + + align:start position:0% +things up the idea is you come in here +and you want to leave out there uh so + + align:start position:0% +and you want to leave out there uh so + + + align:start position:0% +and you want to leave out there uh so +it's unidirectional you can't go up in + + align:start position:0% +it's unidirectional you can't go up in + + + align:start position:0% +it's unidirectional you can't go up in +this gadget and the idea is there's a + + align:start position:0% +this gadget and the idea is there's a + + + align:start position:0% +this gadget and the idea is there's a +little Gap uh and it's moving this way + + align:start position:0% +little Gap uh and it's moving this way + + + align:start position:0% +little Gap uh and it's moving this way +as the monsters move around so you wait + + align:start position:0% +as the monsters move around so you wait + + + align:start position:0% +as the monsters move around so you wait +for the Gap to come here then you go + + align:start position:0% +for the Gap to come here then you go + + + align:start position:0% +for the Gap to come here then you go +down and then you basically forced in + + align:start position:0% +down and then you basically forced in + + + align:start position:0% +down and then you basically forced in +timing when you fall down this + + align:start position:0% +timing when you fall down this + + + align:start position:0% +timing when you fall down this +Cavern and it's set up so that by the + + align:start position:0% +Cavern and it's set up so that by the + + + align:start position:0% +Cavern and it's set up so that by the +time that hap by this time this thing + + align:start position:0% +time that hap by this time this thing + + + align:start position:0% +time that hap by this time this thing +gets to here uh these guys will have + + align:start position:0% +gets to here uh these guys will have + + + align:start position:0% +gets to here uh these guys will have +come to the other side and then you have + + align:start position:0% +come to the other side and then you have + + + align:start position:0% +come to the other side and then you have +to roll to the right in order to avoid + + align:start position:0% +to roll to the right in order to avoid + + + align:start position:0% +to roll to the right in order to avoid +taking damage from these guys who are + + align:start position:0% +taking damage from these guys who are + + + align:start position:0% +taking damage from these guys who are +going around the other way and similarly + + align:start position:0% +going around the other way and similarly + + + align:start position:0% +going around the other way and similarly +in the other direction + + align:start position:0% +in the other direction + + + align:start position:0% +in the other direction +uh so you have to get the timing right + + align:start position:0% +uh so you have to get the timing right + + + align:start position:0% +uh so you have to get the timing right +and we haven't exactly tested this yet + + align:start position:0% +and we haven't exactly tested this yet + + + align:start position:0% +and we haven't exactly tested this yet +but it should be approximately correct + + align:start position:0% +but it should be approximately correct + + + align:start position:0% +but it should be approximately correct +um and that will force a crossover + + align:start position:0% +um and that will force a crossover + + + align:start position:0% +um and that will force a crossover +should be a simpler way but that's the + + align:start position:0% +should be a simpler way but that's the + + + align:start position:0% +should be a simpler way but that's the +best crossover we have + + align:start position:0% +best crossover we have + + + align:start position:0% +best crossover we have +currently uh so Metroid is NP here we + + align:start position:0% +currently uh so Metroid is NP here we + + + align:start position:0% +currently uh so Metroid is NP here we +actually claim mp completeness uh + + align:start position:0% +actually claim mp completeness uh + + + align:start position:0% +actually claim mp completeness uh +because there isn't too much state to + + align:start position:0% +because there isn't too much state to + + + align:start position:0% +because there isn't too much state to +the game um uh so the the issue here is + + align:start position:0% +the game um uh so the the issue here is + + + align:start position:0% +the game um uh so the the issue here is +is the length of a solution polinomial + + align:start position:0% +is the length of a solution polinomial + + + align:start position:0% +is the length of a solution polinomial +length if it is then we know it's NP + + align:start position:0% +length if it is then we know it's NP + + + align:start position:0% +length if it is then we know it's NP +then it's in NP and NP complete um and + + align:start position:0% +then it's in NP and NP complete um and + + + align:start position:0% +then it's in NP and NP complete um and +here you can kill each monster only once + + align:start position:0% +here you can kill each monster only once + + + align:start position:0% +here you can kill each monster only once +uh so that's that's the idea uh for and + + align:start position:0% +uh so that's that's the idea uh for and + + + align:start position:0% +uh so that's that's the idea uh for and +the amount of State you have is just + + align:start position:0% +the amount of State you have is just + + + align:start position:0% +the amount of State you have is just +your position and what items you + + align:start position:0% +your position and what items you + + + align:start position:0% +your position and what items you +currently have so you should be able to + + align:start position:0% +currently have so you should be able to + + + align:start position:0% +currently have so you should be able to +solve this in NP and that sort of + + align:start position:0% +solve this in NP and that sort of + + + align:start position:0% +solve this in NP and that sort of +settles the complexity most of these + + align:start position:0% +settles the complexity most of these + + + align:start position:0% +settles the complexity most of these +other problems could potentially be + + align:start position:0% +other problems could potentially be + + + align:start position:0% +other problems could potentially be +harder than NP and we have some other + + align:start position:0% +harder than NP and we have some other + + + align:start position:0% +harder than NP and we have some other +results like that which we may get to + + align:start position:0% +results like that which we may get to + + + align:start position:0% +results like that which we may get to +when we're talking about ppace but today + + align:start position:0% +when we're talking about ppace but today + + + align:start position:0% +when we're talking about ppace but today +is about + + align:start position:0% +is about + + + align:start position:0% +is about +NP uh here's Donkey Kong Country if you + + align:start position:0% +NP uh here's Donkey Kong Country if you + + + align:start position:0% +NP uh here's Donkey Kong Country if you +haven't played I this is a speedrun + + align:start position:0% +haven't played I this is a speedrun + + + align:start position:0% +haven't played I this is a speedrun +uh and uh you can kill monsters by + + align:start position:0% +uh and uh you can kill monsters by + + + align:start position:0% +uh and uh you can kill monsters by +Rolling most of the time you're jumping + + align:start position:0% +Rolling most of the time you're jumping + + + align:start position:0% +Rolling most of the time you're jumping +um and collecting bananas uh there are + + align:start position:0% +um and collecting bananas uh there are + + + align:start position:0% +um and collecting bananas uh there are +these bees that if you touch them you + + align:start position:0% +these bees that if you touch them you + + + align:start position:0% +these bees that if you touch them you +die or uh you sort of have two hit + + align:start position:0% +die or uh you sort of have two hit + + + align:start position:0% +die or uh you sort of have two hit +points and then there are these barrels + + align:start position:0% +points and then there are these barrels + + + align:start position:0% +points and then there are these barrels +you can pick up that's a giant bee you + + align:start position:0% +you can pick up that's a giant bee you + + + align:start position:0% +you can pick up that's a giant bee you +can pick up some certain barrels and + + align:start position:0% +can pick up some certain barrels and + + + align:start position:0% +can pick up some certain barrels and +then throw them at a monster and in this + + align:start position:0% +then throw them at a monster and in this + + + align:start position:0% +then throw them at a monster and in this +case damage usually kill them then there + + align:start position:0% +case damage usually kill them then there + + + align:start position:0% +case damage usually kill them then there +are these other types of barrels that + + align:start position:0% +are these other types of barrels that + + + align:start position:0% +are these other types of barrels that +when you touch them they shoot you in a + + align:start position:0% +when you touch them they shoot you in a + + + align:start position:0% +when you touch them they shoot you in a +predefined direction and let you collect + + align:start position:0% +predefined direction and let you collect + + + align:start position:0% +predefined direction and let you collect +lots of bananas + + align:start position:0% +lots of bananas + + + align:start position:0% +lots of bananas +okay so that's those are the rules of + + align:start position:0% +okay so that's those are the rules of + + + align:start position:0% +okay so that's those are the rules of +Donkey Kong in a nutshell um in a banana + + align:start position:0% +Donkey Kong in a nutshell um in a banana + + + align:start position:0% +Donkey Kong in a nutshell um in a banana +shell + + align:start position:0% +shell + + + align:start position:0% +shell +I so in a banana peel thank you um so + + align:start position:0% +I so in a banana peel thank you um so + + + align:start position:0% +I so in a banana peel thank you um so +here's a simple Crossover with that + + align:start position:0% +here's a simple Crossover with that + + + align:start position:0% +here's a simple Crossover with that +setup uh you just have these barrels + + align:start position:0% +setup uh you just have these barrels + + + align:start position:0% +setup uh you just have these barrels +that shoot you in a predefined direction + + align:start position:0% +that shoot you in a predefined direction + + + align:start position:0% +that shoot you in a predefined direction +and force you to go through this + + align:start position:0% +and force you to go through this + + + align:start position:0% +and force you to go through this +intersection without any choice when + + align:start position:0% +intersection without any choice when + + + align:start position:0% +intersection without any choice when +you're when you're being shot you cannot + + align:start position:0% +you're when you're being shot you cannot + + + align:start position:0% +you're when you're being shot you cannot +move uh so that's easy uh again + + align:start position:0% +move uh so that's easy uh again + + + align:start position:0% +move uh so that's easy uh again +variables the same as Mario you fall + + align:start position:0% +variables the same as Mario you fall + + + align:start position:0% +variables the same as Mario you fall +left or fall right and a clause uh it's + + align:start position:0% +left or fall right and a clause uh it's + + + align:start position:0% +left or fall right and a clause uh it's +a little hard to see with the background + + align:start position:0% +a little hard to see with the background + + + align:start position:0% +a little hard to see with the background +here but um there's a little ledge here + + align:start position:0% +here but um there's a little ledge here + + + align:start position:0% +here but um there's a little ledge here +and you can come down this way pick up + + align:start position:0% +and you can come down this way pick up + + + align:start position:0% +and you can come down this way pick up +this barrel and throw it over here and + + align:start position:0% +this barrel and throw it over here and + + + align:start position:0% +this barrel and throw it over here and +it will eventually hit this uh B so that + + align:start position:0% +it will eventually hit this uh B so that + + + align:start position:0% +it will eventually hit this uh B so that +later you can Traverse this gadget + + align:start position:0% +later you can Traverse this gadget + + + align:start position:0% +later you can Traverse this gadget +without dying from the B so not drawn is + + align:start position:0% +without dying from the B so not drawn is + + + align:start position:0% +without dying from the B so not drawn is +uh a platform that you need to or maybe + + align:start position:0% +uh a platform that you need to or maybe + + + align:start position:0% +uh a platform that you need to or maybe +you're falling all the way through these + + align:start position:0% +you're falling all the way through these + + + align:start position:0% +you're falling all the way through these +things uh if you set up all the Clauses + + align:start position:0% +things uh if you set up all the Clauses + + + align:start position:0% +things uh if you set up all the Clauses +vertically if there's any B left you + + align:start position:0% +vertically if there's any B left you + + + align:start position:0% +vertically if there's any B left you +will die otherwise not and so you have + + align:start position:0% +will die otherwise not and so you have + + + align:start position:0% +will die otherwise not and so you have +to visit at at least one of these three + + align:start position:0% +to visit at at least one of these three + + + align:start position:0% +to visit at at least one of these three +barrels to kill the + + align:start position:0% +barrels to kill the + + + align:start position:0% +barrels to kill the +bee so uh and I think this is a + + align:start position:0% +bee so uh and I think this is a + + + align:start position:0% +bee so uh and I think this is a +mechanism to prevent you from carrying + + align:start position:0% +mechanism to prevent you from carrying + + + align:start position:0% +mechanism to prevent you from carrying +this Barrel anywhere else uh like + + align:start position:0% +this Barrel anywhere else uh like + + + align:start position:0% +this Barrel anywhere else uh like +climbing up or + + align:start position:0% +climbing up or + + + align:start position:0% +climbing up or +something anyway that's Donkey Kong + + align:start position:0% +something anyway that's Donkey Kong + + + align:start position:0% +something anyway that's Donkey Kong +Country I think there's one more + + align:start position:0% +Country I think there's one more + + + align:start position:0% +Country I think there's one more +Pokemon uh I'm kind of embarrassed I've + + align:start position:0% +Pokemon uh I'm kind of embarrassed I've + + + align:start position:0% +Pokemon uh I'm kind of embarrassed I've +never actually played a Pokemon game I + + align:start position:0% +never actually played a Pokemon game I + + + align:start position:0% +never actually played a Pokemon game I +don't know if I should admit this but I + + align:start position:0% +don't know if I should admit this but I + + + align:start position:0% +don't know if I should admit this but I +need to sit down and play them all some + + align:start position:0% +need to sit down and play them all some + + + align:start position:0% +need to sit down and play them all some +some weekend um I did watch Twitch play + + align:start position:0% +some weekend um I did watch Twitch play + + + align:start position:0% +some weekend um I did watch Twitch play +it for a + + align:start position:0% +it for a + + + align:start position:0% +it for a +while going back to the previous slide + + align:start position:0% +while going back to the previous slide + + + align:start position:0% +while going back to the previous slide +in in some of the other + + align:start position:0% +in in some of the other + + + align:start position:0% +in in some of the other +gadgets uh if we satisfied a clause + + align:start position:0% +gadgets uh if we satisfied a clause + + + align:start position:0% +gadgets uh if we satisfied a clause +there was no way to uh you there was a + + align:start position:0% +there was no way to uh you there was a + + + align:start position:0% +there was no way to uh you there was a +barrier between uh setting the clause + + align:start position:0% +barrier between uh setting the clause + + + align:start position:0% +barrier between uh setting the clause +and going through the rest of that thing + + align:start position:0% +and going through the rest of that thing + + + align:start position:0% +and going through the rest of that thing +right so potentially you could get to + + align:start position:0% +right so potentially you could get to + + + align:start position:0% +right so potentially you could get to +the last Clause here kill the bee and + + align:start position:0% +the last Clause here kill the bee and + + + align:start position:0% +the last Clause here kill the bee and +just walk forward without killing the + + align:start position:0% +just walk forward without killing the + + + align:start position:0% +just walk forward without killing the +rest of the stuff + + align:start position:0% +rest of the stuff + + + align:start position:0% +rest of the stuff +uh good question okay yeah I think + + align:start position:0% +uh good question okay yeah I think + + + align:start position:0% +uh good question okay yeah I think +probably the right way to set this up uh + + align:start position:0% +probably the right way to set this up uh + + + align:start position:0% +probably the right way to set this up uh +I'm not quite sure how to do it directly + + align:start position:0% +I'm not quite sure how to do it directly + + + align:start position:0% +I'm not quite sure how to do it directly +from the drawing but an easy way to do + + align:start position:0% +from the drawing but an easy way to do + + + align:start position:0% +from the drawing but an easy way to do +it would be there's there's no floor + + align:start position:0% +it would be there's there's no floor + + + align:start position:0% +it would be there's there's no floor +below here uh and at the end when you + + align:start position:0% +below here uh and at the end when you + + + align:start position:0% +below here uh and at the end when you +solved all the things there is one of + + align:start position:0% +solved all the things there is one of + + + align:start position:0% +solved all the things there is one of +these barrels that shoots you straight + + align:start position:0% +these barrels that shoots you straight + + + align:start position:0% +these barrels that shoots you straight +to the left until you get to the + + align:start position:0% +to the left until you get to the + + + align:start position:0% +to the left until you get to the +finish uh so you if you tried to exit + + align:start position:0% +finish uh so you if you tried to exit + + + align:start position:0% +finish uh so you if you tried to exit +the claws early you would just fall to + + align:start position:0% +the claws early you would just fall to + + + align:start position:0% +the claws early you would just fall to +your death because there's only one + + align:start position:0% +your death because there's only one + + + align:start position:0% +your death because there's only one +barrel shooting way over on the right + + align:start position:0% +barrel shooting way over on the right + + + align:start position:0% +barrel shooting way over on the right +that be one solution I forget exactly + + align:start position:0% +that be one solution I forget exactly + + + align:start position:0% +that be one solution I forget exactly +what's in the paper but wouldn't + + align:start position:0% +what's in the paper but wouldn't + + + align:start position:0% +what's in the paper but wouldn't +surprise me if it's that yeah good + + align:start position:0% +surprise me if it's that yeah good + + + align:start position:0% +surprise me if it's that yeah good +question you definitely don't want to be + + align:start position:0% +question you definitely don't want to be + + + align:start position:0% +question you definitely don't want to be +able to just visit the last Clause kill + + align:start position:0% +able to just visit the last Clause kill + + + align:start position:0% +able to just visit the last Clause kill +the guy and then exit that would be that + + align:start position:0% +the guy and then exit that would be that + + + align:start position:0% +the guy and then exit that would be that +would be cheating but in these proofs + + align:start position:0% +would be cheating but in these proofs + + + align:start position:0% +would be cheating but in these proofs +that's always what you have to worry + + align:start position:0% +that's always what you have to worry + + + align:start position:0% +that's always what you have to worry +about is this type of cheating other + + align:start position:0% +about is this type of cheating other + + + align:start position:0% +about is this type of cheating other +questions + + align:start position:0% +questions + + + align:start position:0% +questions +cool uh Pokemon time um so + + align:start position:0% +cool uh Pokemon time um so + + + align:start position:0% +cool uh Pokemon time um so +uh Pokemon is a somewhat complicated + + align:start position:0% +uh Pokemon is a somewhat complicated + + + align:start position:0% +uh Pokemon is a somewhat complicated +game um a lot of different abilities and + + align:start position:0% +game um a lot of different abilities and + + + align:start position:0% +game um a lot of different abilities and +so on so we had to abstract things away + + align:start position:0% +so on so we had to abstract things away + + + align:start position:0% +so on so we had to abstract things away +and in these pictures there are two + + align:start position:0% +and in these pictures there are two + + + align:start position:0% +and in these pictures there are two +types of uh I haven't defined any of the + + align:start position:0% +types of uh I haven't defined any of the + + + align:start position:0% +types of uh I haven't defined any of the +rules yet you are a little uh person + + align:start position:0% +rules yet you are a little uh person + + + align:start position:0% +rules yet you are a little uh person +walking around here uh you're carrying + + align:start position:0% +walking around here uh you're carrying + + + align:start position:0% +walking around here uh you're carrying +Pokemon whatever uh and there are these + + align:start position:0% +Pokemon whatever uh and there are these + + + align:start position:0% +Pokemon whatever uh and there are these +these characters called trainers and uh + + align:start position:0% +these characters called trainers and uh + + + align:start position:0% +these characters called trainers and uh +the the red trainers are called weak + + align:start position:0% +the the red trainers are called weak + + + align:start position:0% +the the red trainers are called weak +trainers these are people that when you + + align:start position:0% +trainers these are people that when you + + + align:start position:0% +trainers these are people that when you +visit they just sort of deactivate you + + align:start position:0% +visit they just sort of deactivate you + + + align:start position:0% +visit they just sort of deactivate you +beat them and then there's blue trainers + + align:start position:0% +beat them and then there's blue trainers + + + align:start position:0% +beat them and then there's blue trainers +we'll call them strong trainers those + + align:start position:0% +we'll call them strong trainers those + + + align:start position:0% +we'll call them strong trainers those +are ones that no matter how no matter + + align:start position:0% +are ones that no matter how no matter + + + align:start position:0% +are ones that no matter how no matter +when or how you try to play them you + + align:start position:0% +when or how you try to play them you + + + align:start position:0% +when or how you try to play them you +always die and so you fail so you never + + align:start position:0% +always die and so you fail so you never + + + align:start position:0% +always die and so you fail so you never +want to visit blue trainer uh now + + align:start position:0% +want to visit blue trainer uh now + + + align:start position:0% +want to visit blue trainer uh now +trainers have two kinds of uh let's talk + + align:start position:0% +trainers have two kinds of uh let's talk + + + align:start position:0% +trainers have two kinds of uh let's talk +about variables maybe this is an easy + + align:start position:0% +about variables maybe this is an easy + + + align:start position:0% +about variables maybe this is an easy +situation uh so variable you want to + + align:start position:0% +situation uh so variable you want to + + + align:start position:0% +situation uh so variable you want to +come in the in and either leave in the + + align:start position:0% +come in the in and either leave in the + + + align:start position:0% +come in the in and either leave in the +false or leave in the true and there are + + align:start position:0% +false or leave in the true and there are + + + align:start position:0% +false or leave in the true and there are +two ways to activate a trainer one is to + + align:start position:0% +two ways to activate a trainer one is to + + + align:start position:0% +two ways to activate a trainer one is to +walk into their field of view so when + + align:start position:0% +walk into their field of view so when + + + align:start position:0% +walk into their field of view so when +you which are drawn with these + + align:start position:0% +you which are drawn with these + + + align:start position:0% +you which are drawn with these +rectangles if you walk to this position + + align:start position:0% +rectangles if you walk to this position + + + align:start position:0% +rectangles if you walk to this position +the trainer will walk to you + + align:start position:0% +the trainer will walk to you + + + align:start position:0% +the trainer will walk to you +and then you fight the trainer okay and + + align:start position:0% +and then you fight the trainer okay and + + + align:start position:0% +and then you fight the trainer okay and +because it's red you'll win and so in + + align:start position:0% +because it's red you'll win and so in + + + align:start position:0% +because it's red you'll win and so in +that case the trainer has moved here + + align:start position:0% +that case the trainer has moved here + + + align:start position:0% +that case the trainer has moved here +trainers are obstacles so you can uh you + + align:start position:0% +trainers are obstacles so you can uh you + + + align:start position:0% +trainers are obstacles so you can uh you +can't get to the true anymore you have + + align:start position:0% +can't get to the true anymore you have + + + align:start position:0% +can't get to the true anymore you have +to go around to false the other way you + + align:start position:0% +to go around to false the other way you + + + align:start position:0% +to go around to false the other way you +can visit a trainer is to talk to them + + align:start position:0% +can visit a trainer is to talk to them + + + align:start position:0% +can visit a trainer is to talk to them +from the side or from behind so you can + + align:start position:0% +from the side or from behind so you can + + + align:start position:0% +from the side or from behind so you can +walk here talk to the trainer beat them + + align:start position:0% +walk here talk to the trainer beat them + + + align:start position:0% +walk here talk to the trainer beat them +then they deactivate then you can walk + + align:start position:0% +then they deactivate then you can walk + + + align:start position:0% +then they deactivate then you can walk +this way and you can only fight them + + align:start position:0% +this way and you can only fight them + + + align:start position:0% +this way and you can only fight them +once then it's it's they won't move + + align:start position:0% +once then it's it's they won't move + + + align:start position:0% +once then it's it's they won't move +anymore so uh that forces you to do true + + align:start position:0% +anymore so uh that forces you to do true + + + align:start position:0% +anymore so uh that forces you to do true +or false and then commit to that + + align:start position:0% +or false and then commit to that + + + align:start position:0% +or false and then commit to that +decision + + align:start position:0% + + + + align:start position:0% + +okay um and these are obviously + + align:start position:0% +okay um and these are obviously + + + align:start position:0% +okay um and these are obviously +obstacles they're immovable all right so + + align:start position:0% +obstacles they're immovable all right so + + + align:start position:0% +obstacles they're immovable all right so +the idea with a clause + + align:start position:0% +the idea with a clause + + + align:start position:0% +the idea with a clause +is uh the following you're when you're + + align:start position:0% +is uh the following you're when you're + + + align:start position:0% +is uh the following you're when you're +TR traversing the Clause at the end you + + align:start position:0% +TR traversing the Clause at the end you + + + align:start position:0% +TR traversing the Clause at the end you +want to walk through here and leave and + + align:start position:0% +want to walk through here and leave and + + + align:start position:0% +want to walk through here and leave and +the worry is this position if this + + align:start position:0% +the worry is this position if this + + + align:start position:0% +the worry is this position if this +trainer uh can come to you you will + + align:start position:0% +trainer uh can come to you you will + + + align:start position:0% +trainer uh can come to you you will +die okay + + align:start position:0% +die okay + + + align:start position:0% +die okay +so uh that will be possible exactly when + + align:start position:0% +so uh that will be possible exactly when + + + align:start position:0% +so uh that will be possible exactly when +all of these guys are out of the way + + align:start position:0% +all of these guys are out of the way + + + align:start position:0% +all of these guys are out of the way +when will they come out of the way when + + align:start position:0% +when will they come out of the way when + + + align:start position:0% +when will they come out of the way when +you walk through them and none of them + + align:start position:0% +you walk through them and none of them + + + align:start position:0% +you walk through them and none of them +have been activated yet so then they + + align:start position:0% +have been activated yet so then they + + + align:start position:0% +have been activated yet so then they +will walk one space to you you'll win + + align:start position:0% +will walk one space to you you'll win + + + align:start position:0% +will walk one space to you you'll win +but uh it's + + align:start position:0% +but uh it's + + + align:start position:0% +but uh it's +temporary you win the battle lose the + + align:start position:0% +temporary you win the battle lose the + + + align:start position:0% +temporary you win the battle lose the +war because when you get here then this + + align:start position:0% +war because when you get here then this + + + align:start position:0% +war because when you get here then this +guy can walk through uh but these serve + + align:start position:0% +guy can walk through uh but these serve + + + align:start position:0% +guy can walk through uh but these serve +as obstacles otherwise so um if you can + + align:start position:0% +as obstacles otherwise so um if you can + + + align:start position:0% +as obstacles otherwise so um if you can +come down one of these paths and visit + + align:start position:0% +come down one of these paths and visit + + + align:start position:0% +come down one of these paths and visit +the trainer early then later when you + + align:start position:0% +the trainer early then later when you + + + align:start position:0% +the trainer early then later when you +come through they will not move towards + + align:start position:0% +come through they will not move towards + + + align:start position:0% +come through they will not move towards +you they will stay an obstacle for this + + align:start position:0% +you they will stay an obstacle for this + + + align:start position:0% +you they will stay an obstacle for this +guy and so this I cannot walk to you + + align:start position:0% +guy and so this I cannot walk to you + + + align:start position:0% +guy and so this I cannot walk to you +this is just to make a barrier uh and + + align:start position:0% +this is just to make a barrier uh and + + + align:start position:0% +this is just to make a barrier uh and +then then you can get through okay + + align:start position:0% +then then you can get through okay + + + align:start position:0% +then then you can get through okay +crossover you get the idea right uh we + + align:start position:0% +crossover you get the idea right uh we + + + align:start position:0% +crossover you get the idea right uh we +could try to walk through it but it's + + align:start position:0% +could try to walk through it but it's + + + align:start position:0% +could try to walk through it but it's +definitely complicated General we want + + align:start position:0% +definitely complicated General we want + + + align:start position:0% +definitely complicated General we want +to go from X to X prime or Y to Y Prime + + align:start position:0% +to go from X to X prime or Y to Y Prime + + + align:start position:0% +to go from X to X prime or Y to Y Prime +again it's + + align:start position:0% +again it's + + + align:start position:0% +again it's +directional uh and now that I know the + + align:start position:0% +directional uh and now that I know the + + + align:start position:0% +directional uh and now that I know the +right color assignment red is weak I + + align:start position:0% +right color assignment red is weak I + + + align:start position:0% +right color assignment red is weak I +would guess + + align:start position:0% +would guess + + + align:start position:0% +would guess +uh yeah this guy has an obstacle but as + + align:start position:0% +uh yeah this guy has an obstacle but as + + + align:start position:0% +uh yeah this guy has an obstacle but as +soon as you go this way this guy moves + + align:start position:0% +soon as you go this way this guy moves + + + align:start position:0% +soon as you go this way this guy moves +out of the way so it kind of closes off + + align:start position:0% +out of the way so it kind of closes off + + + align:start position:0% +out of the way so it kind of closes off +trying to return this way so once you + + align:start position:0% +trying to return this way so once you + + + align:start position:0% +trying to return this way so once you +come through here this uh would be a + + align:start position:0% +come through here this uh would be a + + + align:start position:0% +come through here this uh would be a +problem to come back so that kind of + + align:start position:0% +problem to come back so that kind of + + + align:start position:0% +problem to come back so that kind of +cuts you off from going back and uh it's + + align:start position:0% +cuts you off from going back and uh it's + + + align:start position:0% +cuts you off from going back and uh it's +kind of like the crossover we saw with + + align:start position:0% +kind of like the crossover we saw with + + + align:start position:0% +kind of like the crossover we saw with +push one 2D I + + align:start position:0% +push one 2D I + + + align:start position:0% +push one 2D I +believe uh then you probably go here + + align:start position:0% +believe uh then you probably go here + + + align:start position:0% +believe uh then you probably go here +similar thing happens go this guy will + + align:start position:0% +similar thing happens go this guy will + + + align:start position:0% +similar thing happens go this guy will +approach come to you uh and then you can + + align:start position:0% +approach come to you uh and then you can + + + align:start position:0% +approach come to you uh and then you can +escape when you get here this guy will + + align:start position:0% +escape when you get here this guy will + + + align:start position:0% +escape when you get here this guy will +come all the way down oh that looks bad + + align:start position:0% +come all the way down oh that looks bad + + + align:start position:0% +come all the way down oh that looks bad +can yeah so probably we should have + + align:start position:0% +can yeah so probably we should have + + + align:start position:0% +can yeah so probably we should have +talked to him early so then we can come + + align:start position:0% +talked to him early so then we can come + + + align:start position:0% +talked to him early so then we can come +through here without any trouble + + align:start position:0% +through here without any trouble + + + align:start position:0% +through here without any trouble +succeeded in getting down to Y Prime you + + align:start position:0% +succeeded in getting down to Y Prime you + + + align:start position:0% +succeeded in getting down to Y Prime you +have to check that you can't get to X + + align:start position:0% +have to check that you can't get to X + + + align:start position:0% +have to check that you can't get to X +Prime this looks like a impossible Nexus + + align:start position:0% +Prime this looks like a impossible Nexus + + + align:start position:0% +Prime this looks like a impossible Nexus +to get through but these guys can walk + + align:start position:0% +to get through but these guys can walk + + + align:start position:0% +to get through but these guys can walk +through that's the reason they're there + + align:start position:0% +through that's the reason they're there + + + align:start position:0% +through that's the reason they're there +instead of just being + + align:start position:0% +instead of just being + + + align:start position:0% +instead of just being +obstacles uh left left to right should + + align:start position:0% +obstacles uh left left to right should + + + align:start position:0% +obstacles uh left left to right should +be sorry they can only see you like five + + align:start position:0% +be sorry they can only see you like five + + + align:start position:0% +be sorry they can only see you like five +or six piles away this is a generalized + + align:start position:0% +or six piles away this is a generalized + + + align:start position:0% +or six piles away this is a generalized +Pokemon yeah it would be nice I mean + + align:start position:0% +Pokemon yeah it would be nice I mean + + + align:start position:0% +Pokemon yeah it would be nice I mean +obviously this is a bounded visibility + + align:start position:0% +obviously this is a bounded visibility + + + align:start position:0% +obviously this is a bounded visibility +it would be nice to get it to get that + + align:start position:0% +it would be nice to get it to get that + + + align:start position:0% +it would be nice to get it to get that +bound smaller uh but at least this shows + + align:start position:0% +bound smaller uh but at least this shows + + + align:start position:0% +bound smaller uh but at least this shows +constant visibility is enough these + + align:start position:0% +constant visibility is enough these + + + align:start position:0% +constant visibility is enough these +gadgets are all + + align:start position:0% +gadgets are all + + + align:start position:0% +gadgets are all +local uh it would maybe also be nice are + + align:start position:0% +local uh it would maybe also be nice are + + + align:start position:0% +local uh it would maybe also be nice are +they all the + + align:start position:0% +they all the + + + align:start position:0% +they all the +same it's just some fix so it would be + + align:start position:0% +same it's just some fix so it would be + + + align:start position:0% +same it's just some fix so it would be +nice if they were also all the same uh + + align:start position:0% +nice if they were also all the same uh + + + align:start position:0% +nice if they were also all the same uh +that + + align:start position:0% +that + + + align:start position:0% +that +does not currently hold but wouldn't + + align:start position:0% +does not currently hold but wouldn't + + + align:start position:0% +does not currently hold but wouldn't +surprise me if that well yeah + + align:start position:0% +surprise me if that well yeah + + + align:start position:0% +surprise me if that well yeah +tricky all right uh I'll just mention uh + + align:start position:0% +tricky all right uh I'll just mention uh + + + align:start position:0% +tricky all right uh I'll just mention uh +for a little bit of Pokemon cred this is + + align:start position:0% +for a little bit of Pokemon cred this is + + + align:start position:0% +for a little bit of Pokemon cred this is +one uh paragraph of our paper uh where + + align:start position:0% +one uh paragraph of our paper uh where + + + align:start position:0% +one uh paragraph of our paper uh where +we con + + align:start position:0% +we con + + + align:start position:0% +we con +construct construct the weak and the + + align:start position:0% +construct construct the weak and the + + + align:start position:0% +construct construct the weak and the +strong trainers um to use using exactly + + align:start position:0% +strong trainers um to use using exactly + + + align:start position:0% +strong trainers um to use using exactly +the setup that's available in various + + align:start position:0% +the setup that's available in various + + + align:start position:0% +the setup that's available in various +Pokemon games I I I believe in every + + align:start position:0% +Pokemon games I I I believe in every + + + align:start position:0% +Pokemon games I I I believe in every +single game there are enough uh + + align:start position:0% +single game there are enough uh + + + align:start position:0% +single game there are enough uh +abilities that you can set up uh so that + + align:start position:0% +abilities that you can set up uh so that + + + align:start position:0% +abilities that you can set up uh so that +you either Force the bad guy to all he + + align:start position:0% +you either Force the bad guy to all he + + + align:start position:0% +you either Force the bad guy to all he +can do is self-destruct or uh all he can + + align:start position:0% +can do is self-destruct or uh all he can + + + align:start position:0% +can do is self-destruct or uh all he can +do is kill you and you lose that sort of + + align:start position:0% +do is kill you and you lose that sort of + + + align:start position:0% +do is kill you and you lose that sort of +thing uh but it take requires some + + align:start position:0% +thing uh but it take requires some + + + align:start position:0% +thing uh but it take requires some +Pokemon expertise with which uh uh Alan + + align:start position:0% +Pokemon expertise with which uh uh Alan + + + align:start position:0% +Pokemon expertise with which uh uh Alan +guo had in this case he's a PhD student + + align:start position:0% +guo had in this case he's a PhD student + + + align:start position:0% +guo had in this case he's a PhD student +in Cale + + align:start position:0% +in Cale + + + align:start position:0% +in Cale +here okay um any other questions about + + align:start position:0% +here okay um any other questions about + + + align:start position:0% +here okay um any other questions about +uh Nintendo games before we move on yeah + + align:start position:0% +uh Nintendo games before we move on yeah + + + align:start position:0% +uh Nintendo games before we move on yeah +uh this is a common sort of fork + + align:start position:0% +uh this is a common sort of fork + + + align:start position:0% +uh this is a common sort of fork +specific in generation one can miss with + + align:start position:0% +specific in generation one can miss with + + + align:start position:0% +specific in generation one can miss with +a one and 255 CH yeah chess even if + + align:start position:0% +a one and 255 CH yeah chess even if + + + align:start position:0% +a one and 255 CH yeah chess even if +their accuracy is 100% uh how do you + + align:start position:0% +their accuracy is 100% uh how do you + + + align:start position:0% +their accuracy is 100% uh how do you +deal with + + align:start position:0% + + + + align:start position:0% + +this + + align:start position:0% + + + + align:start position:0% + +sestru SRU miss it doesn't die no but + + align:start position:0% +sestru SRU miss it doesn't die no but + + + align:start position:0% +sestru SRU miss it doesn't die no but +self-destruct doesn't matter whether it + + align:start position:0% +self-destruct doesn't matter whether it + + + align:start position:0% +self-destruct doesn't matter whether it +does damage right it's just kind of you + + align:start position:0% +does damage right it's just kind of you + + + align:start position:0% +does damage right it's just kind of you +self-destruct you die yeah I think I + + align:start position:0% +self-destruct you die yeah I think I + + + align:start position:0% +self-destruct you die yeah I think I +think self-destruct but the death + + align:start position:0% +think self-destruct but the death + + + align:start position:0% +think self-destruct but the death +doesn't actually happen if the attack + + align:start position:0% +doesn't actually happen if the attack + + + align:start position:0% +doesn't actually happen if the attack +misses can you no it does does really + + align:start position:0% +misses can you no it does does really + + + align:start position:0% +misses can you no it does does really +okay yeah it + + align:start position:0% +okay yeah it + + + align:start position:0% +okay yeah it +does we'll have to go + + align:start position:0% + + + + align:start position:0% + +play all right um the next game I'm + + align:start position:0% +play all right um the next game I'm + + + align:start position:0% +play all right um the next game I'm +going to talk about is a sort of + + align:start position:0% +going to talk about is a sort of + + + align:start position:0% +going to talk about is a sort of +physical game that you play on usually a + + align:start position:0% +physical game that you play on usually a + + + align:start position:0% +physical game that you play on usually a +go board with go Stones uh so there are + + align:start position:0% +go board with go Stones uh so there are + + + align:start position:0% +go board with go Stones uh so there are +white stones and black Stones this is is + + align:start position:0% +white stones and black Stones this is is + + + align:start position:0% +white stones and black Stones this is is +invented by this guy John Conway um as + + align:start position:0% +invented by this guy John Conway um as + + + align:start position:0% +invented by this guy John Conway um as +if you've ever played Conway's Game of + + align:start position:0% +if you've ever played Conway's Game of + + + align:start position:0% +if you've ever played Conway's Game of +Life it's not that's a zero player game + + align:start position:0% +Life it's not that's a zero player game + + + align:start position:0% +Life it's not that's a zero player game +this is an actual two-player game and + + align:start position:0% +this is an actual two-player game and + + + align:start position:0% +this is an actual two-player game and +quite challenging in here's the the + + align:start position:0% +quite challenging in here's the the + + + align:start position:0% +quite challenging in here's the the +general idea there's a right player + + align:start position:0% +general idea there's a right player + + + align:start position:0% +general idea there's a right player +trying to get the white ball that's the + + align:start position:0% +trying to get the white ball that's the + + + align:start position:0% +trying to get the white ball that's the +football this is philosopher football if + + align:start position:0% +football this is philosopher football if + + + align:start position:0% +football this is philosopher football if +you will um you're trying to get this + + align:start position:0% +you will um you're trying to get this + + + align:start position:0% +you will um you're trying to get this +ball over to that goal and the left + + align:start position:0% +ball over to that goal and the left + + + align:start position:0% +ball over to that goal and the left +player is trying to get the ball to the + + align:start position:0% +player is trying to get the ball to the + + + align:start position:0% +player is trying to get the ball to the +right goal then there are these uh black + + align:start position:0% +right goal then there are these uh black + + + align:start position:0% +right goal then there are these uh black +pieces which are called men those are + + align:start position:0% +pieces which are called men those are + + + align:start position:0% +pieces which are called men those are +the players of the game so to speak um + + align:start position:0% +the players of the game so to speak um + + + align:start position:0% +the players of the game so to speak um +and there are two types of move in this + + align:start position:0% +and there are two types of move in this + + + align:start position:0% +and there are two types of move in this +game one move you can do is just place a + + align:start position:0% +game one move you can do is just place a + + + align:start position:0% +game one move you can do is just place a +black stone anywhere on the board that's + + align:start position:0% +black stone anywhere on the board that's + + + align:start position:0% +black stone anywhere on the board that's +currently empty and the other type of + + align:start position:0% +currently empty and the other type of + + + align:start position:0% +currently empty and the other type of +move is the more complicated one this is + + align:start position:0% +move is the more complicated one this is + + + align:start position:0% +move is the more complicated one this is +called kicking the ball you can take the + + align:start position:0% +called kicking the ball you can take the + + + align:start position:0% +called kicking the ball you can take the +white piece and you can jump it over a + + align:start position:0% +white piece and you can jump it over a + + + align:start position:0% +white piece and you can jump it over a +string of black of consecutive black + + align:start position:0% +string of black of consecutive black + + + align:start position:0% +string of black of consecutive black +pieces those pieces are immediately + + align:start position:0% +pieces those pieces are immediately + + + align:start position:0% +pieces those pieces are immediately +removed so the these gray shading means + + align:start position:0% +removed so the these gray shading means + + + align:start position:0% +removed so the these gray shading means +they've been removed from the board uh + + align:start position:0% +they've been removed from the board uh + + + align:start position:0% +they've been removed from the board uh +but in the same move you can do several + + align:start position:0% +but in the same move you can do several + + + align:start position:0% +but in the same move you can do several +such jumps so I can jump here then I can + + align:start position:0% +such jumps so I can jump here then I can + + + align:start position:0% +such jumps so I can jump here then I can +jump here uh then I can jump here uh + + align:start position:0% +jump here uh then I can jump here uh + + + align:start position:0% +jump here uh then I can jump here uh +then I can jump here and everything I + + align:start position:0% +then I can jump here and everything I + + + align:start position:0% +then I can jump here and everything I +jump over in this case I won uh if I'm + + align:start position:0% +jump over in this case I won uh if I'm + + + align:start position:0% +jump over in this case I won uh if I'm +the right player I got to that position + + align:start position:0% +the right player I got to that position + + + align:start position:0% +the right player I got to that position +so this is why the right player from the + + align:start position:0% +so this is why the right player from the + + + align:start position:0% +so this is why the right player from the +original position maybe they wanted to + + align:start position:0% +original position maybe they wanted to + + + align:start position:0% +original position maybe they wanted to +place this Stone uh because that would + + align:start position:0% +place this Stone uh because that would + + + align:start position:0% +place this Stone uh because that would +enable in their next move you can't + + align:start position:0% +enable in their next move you can't + + + align:start position:0% +enable in their next move you can't +place a black stone and then jump you + + align:start position:0% +place a black stone and then jump you + + + align:start position:0% +place a black stone and then jump you +can do one or the other so you could try + + align:start position:0% +can do one or the other so you could try + + + align:start position:0% +can do one or the other so you could try +to place this position place the stone + + align:start position:0% +to place this position place the stone + + + align:start position:0% +to place this position place the stone +hoping that in your next turn you'll be + + align:start position:0% +hoping that in your next turn you'll be + + + align:start position:0% +hoping that in your next turn you'll be +able to do this jump and win uh but uh + + align:start position:0% +able to do this jump and win uh but uh + + + align:start position:0% +able to do this jump and win uh but uh +instead from this position the left + + align:start position:0% +instead from this position the left + + + align:start position:0% +instead from this position the left +player could say oh I'll just add this + + align:start position:0% +player could say oh I'll just add this + + + align:start position:0% +player could say oh I'll just add this +Stone and then I in my next move I'll be + + align:start position:0% +Stone and then I in my next move I'll be + + + align:start position:0% +Stone and then I in my next move I'll be +able to jump to the right right side U + + align:start position:0% +able to jump to the right right side U + + + align:start position:0% +able to jump to the right right side U +that's I think unblockable so left wins + + align:start position:0% +that's I think unblockable so left wins + + + align:start position:0% +that's I think unblockable so left wins +yay um so that's that's a setup uh now + + align:start position:0% +yay um so that's that's a setup uh now + + + align:start position:0% +yay um so that's that's a setup uh now +this is a fairly complicated game uh you + + align:start position:0% +this is a fairly complicated game uh you + + + align:start position:0% +this is a fairly complicated game uh you +can get to the same position multiple + + align:start position:0% +can get to the same position multiple + + + align:start position:0% +can get to the same position multiple +times uh and so it's actually open how + + align:start position:0% +times uh and so it's actually open how + + + align:start position:0% +times uh and so it's actually open how +hard this game is I think there's an + + align:start position:0% +hard this game is I think there's an + + + align:start position:0% +hard this game is I think there's an +upper bound of it being solvable in + + align:start position:0% +upper bound of it being solvable in + + + align:start position:0% +upper bound of it being solvable in +exponential time so it's in exp what Sol + + align:start position:0% +exponential time so it's in exp what Sol + + + align:start position:0% +exponential time so it's in exp what Sol +so you given a position you want to know + + align:start position:0% +so you given a position you want to know + + + align:start position:0% +so you given a position you want to know +whether left or right will win from this + + align:start position:0% +whether left or right will win from this + + + align:start position:0% +whether left or right will win from this +position is it possible that it doesn't + + align:start position:0% +position is it possible that it doesn't + + + align:start position:0% +position is it possible that it doesn't +terminate uh it could be Tai is the + + align:start position:0% +terminate uh it could be Tai is the + + + align:start position:0% +terminate uh it could be Tai is the +right answer y so that's tricky uh it + + align:start position:0% +right answer y so that's tricky uh it + + + align:start position:0% +right answer y so that's tricky uh it +there is a PE Bas hardness result + + align:start position:0% +there is a PE Bas hardness result + + + align:start position:0% +there is a PE Bas hardness result +relatively recent uh but an old result + + align:start position:0% +relatively recent uh but an old result + + + align:start position:0% +relatively recent uh but an old result +of ours uh with David Epstein uh is that + + align:start position:0% +of ours uh with David Epstein uh is that + + + align:start position:0% +of ours uh with David Epstein uh is that +just determining whether you can win in + + align:start position:0% +just determining whether you can win in + + + align:start position:0% +just determining whether you can win in +one move is NP complete so that that's a + + align:start position:0% +one move is NP complete so that that's a + + + align:start position:0% +one move is NP complete so that that's a +relatively clean thing you don't have to + + align:start position:0% +relatively clean thing you don't have to + + + align:start position:0% +relatively clean thing you don't have to +worry about non-termination or that sort + + align:start position:0% +worry about non-termination or that sort + + + align:start position:0% +worry about non-termination or that sort +of thing it's just one player's move + + align:start position:0% +of thing it's just one player's move + + + align:start position:0% +of thing it's just one player's move +uh here everything is uh reversed we + + align:start position:0% +uh here everything is uh reversed we + + + align:start position:0% +uh here everything is uh reversed we +have the black uh the ball is black in + + align:start position:0% +have the black uh the ball is black in + + + align:start position:0% +have the black uh the ball is black in +this case I'm not sure if there's a + + align:start position:0% +this case I'm not sure if there's a + + + align:start position:0% +this case I'm not sure if there's a +consistent uh notion anyway uh and this + + align:start position:0% +consistent uh notion anyway uh and this + + + align:start position:0% +consistent uh notion anyway uh and this +is actually our reduction all in one + + align:start position:0% +is actually our reduction all in one + + + align:start position:0% +is actually our reduction all in one +slide um it's pretty simple so this is + + align:start position:0% +slide um it's pretty simple so this is + + + align:start position:0% +slide um it's pretty simple so this is +what we call the mate in one problem and + + align:start position:0% +what we call the mate in one problem and + + + align:start position:0% +what we call the mate in one problem and +you can take lots of different games and + + align:start position:0% +you can take lots of different games and + + + align:start position:0% +you can take lots of different games and +make them really clean well-defined + + align:start position:0% +make them really clean well-defined + + + align:start position:0% +make them really clean well-defined +puzzles if you just ask can I win in one + + align:start position:0% +puzzles if you just ask can I win in one + + + align:start position:0% +puzzles if you just ask can I win in one +move even games that involve cards and + + align:start position:0% +move even games that involve cards and + + + align:start position:0% +move even games that involve cards and +Randomness and weird stuff uh in one + + align:start position:0% +Randomness and weird stuff uh in one + + + align:start position:0% +Randomness and weird stuff uh in one +move usually doesn't involve those at + + align:start position:0% +move usually doesn't involve those at + + + align:start position:0% +move usually doesn't involve those at +all anyway here we're getting rid of uh + + align:start position:0% +all anyway here we're getting rid of uh + + + align:start position:0% +all anyway here we're getting rid of uh +the loopiness of the game and not having + + align:start position:0% +the loopiness of the game and not having + + + align:start position:0% +the loopiness of the game and not having +to worry about that so um there's sort + + align:start position:0% +to worry about that so um there's sort + + + align:start position:0% +to worry about that so um there's sort +of two parts to this proof the variable + + align:start position:0% +of two parts to this proof the variable + + + align:start position:0% +of two parts to this proof the variable +traversal and the Clause traversal but + + align:start position:0% +traversal and the Clause traversal but + + + align:start position:0% +traversal and the Clause traversal but +here we have a kind of very different + + align:start position:0% +here we have a kind of very different + + + align:start position:0% +here we have a kind of very different +way of connecting things together we + + align:start position:0% +way of connecting things together we + + + align:start position:0% +way of connecting things together we +have a giant Matrix if you will um we're + + align:start position:0% +have a giant Matrix if you will um we're + + + align:start position:0% +have a giant Matrix if you will um we're +starting up here and we have a choice + + align:start position:0% +starting up here and we have a choice + + + align:start position:0% +starting up here and we have a choice +whether we if we want to set X1 to true + + align:start position:0% +whether we if we want to set X1 to true + + + align:start position:0% +whether we if we want to set X1 to true +we're just going to go to the right uh + + align:start position:0% +we're just going to go to the right uh + + + align:start position:0% +we're just going to go to the right uh +by sequence of jumps we jump here then + + align:start position:0% +by sequence of jumps we jump here then + + + align:start position:0% +by sequence of jumps we jump here then +here then here every time we stop we + + align:start position:0% +here then here every time we stop we + + + align:start position:0% +here then here every time we stop we +have no choice if we want to keep going + + align:start position:0% +have no choice if we want to keep going + + + align:start position:0% +have no choice if we want to keep going +our goal is to get to + + align:start position:0% +our goal is to get to + + + align:start position:0% +our goal is to get to +somewhere one of the edges of the board + + align:start position:0% +somewhere one of the edges of the board + + + align:start position:0% +somewhere one of the edges of the board +I think the bottom Edge yeah bottom Edge + + align:start position:0% +I think the bottom Edge yeah bottom Edge + + + align:start position:0% +I think the bottom Edge yeah bottom Edge +is the one that's hard to get + + align:start position:0% +is the one that's hard to get + + + align:start position:0% +is the one that's hard to get +to uh so every time we jump to the right + + align:start position:0% +to uh so every time we jump to the right + + + align:start position:0% +to uh so every time we jump to the right +here we don't have a choice we have to + + align:start position:0% +here we don't have a choice we have to + + + align:start position:0% +here we don't have a choice we have to +keep jumping to the right uh but over + + align:start position:0% +keep jumping to the right uh but over + + + align:start position:0% +keep jumping to the right uh but over +here we have a choice we could go down + + align:start position:0% +here we have a choice we could go down + + + align:start position:0% +here we have a choice we could go down +and then jump to the right and get over + + align:start position:0% +and then jump to the right and get over + + + align:start position:0% +and then jump to the right and get over +here and that will do different things + + align:start position:0% +here and that will do different things + + + align:start position:0% +here and that will do different things +in the middle in general that is our + + align:start position:0% +in the middle in general that is our + + + align:start position:0% +in the middle in general that is our +setting of X1 then we're going to do the + + align:start position:0% +setting of X1 then we're going to do the + + + align:start position:0% +setting of X1 then we're going to do the +same thing coming back for X2 of two + + align:start position:0% +same thing coming back for X2 of two + + + align:start position:0% +same thing coming back for X2 of two +choices then the same thing going back + + align:start position:0% +choices then the same thing going back + + + align:start position:0% +choices then the same thing going back +for X3 uh and then we get to this corner + + align:start position:0% +for X3 uh and then we get to this corner + + + align:start position:0% +for X3 uh and then we get to this corner +so that's forced other than these + + align:start position:0% +so that's forced other than these + + + align:start position:0% +so that's forced other than these +choices binary + + align:start position:0% +choices binary + + + align:start position:0% +choices binary +choices uh now uh we have our first + + align:start position:0% +choices uh now uh we have our first + + + align:start position:0% +choices uh now uh we have our first +Clause let's say X1 negated or X2 + + align:start position:0% +Clause let's say X1 negated or X2 + + + align:start position:0% +Clause let's say X1 negated or X2 +negated or X3 negated we want one of + + align:start position:0% +negated or X3 negated we want one of + + + align:start position:0% +negated or X3 negated we want one of +those things to be true and uh so the + + align:start position:0% +those things to be true and uh so the + + + align:start position:0% +those things to be true and uh so the +idea is we're going to choose whichever + + align:start position:0% +idea is we're going to choose whichever + + + align:start position:0% +idea is we're going to choose whichever +one uh has been set correctly and then + + align:start position:0% +one uh has been set correctly and then + + + align:start position:0% +one uh has been set correctly and then +we will go up that channel and get to + + align:start position:0% +we will go up that channel and get to + + + align:start position:0% +we will go up that channel and get to +the top again it's pretty much symmetric + + align:start position:0% +the top again it's pretty much symmetric + + + align:start position:0% +the top again it's pretty much symmetric +so every time we jump over a bunch of + + align:start position:0% +so every time we jump over a bunch of + + + align:start position:0% +so every time we jump over a bunch of +pieces whenever we stop we can't go left + + align:start position:0% +pieces whenever we stop we can't go left + + + align:start position:0% +pieces whenever we stop we can't go left +or right we have to keep going up so we + + align:start position:0% +or right we have to keep going up so we + + + align:start position:0% +or right we have to keep going up so we +have to make it all the + + align:start position:0% +have to make it all the + + + align:start position:0% +have to make it all the +way in fact uh each of these columns + + align:start position:0% +way in fact uh each of these columns + + + align:start position:0% +way in fact uh each of these columns +will be completely filled except for one + + align:start position:0% +will be completely filled except for one + + + align:start position:0% +will be completely filled except for one +intersection which is the thing that + + align:start position:0% +intersection which is the thing that + + + align:start position:0% +intersection which is the thing that +makes it false so here we want X2 to be + + align:start position:0% +makes it false so here we want X2 to be + + + align:start position:0% +makes it false so here we want X2 to be +false so if we happen to follow the true + + align:start position:0% +false so if we happen to follow the true + + + align:start position:0% +false so if we happen to follow the true +path where X2 is true we won't make it + + align:start position:0% +path where X2 is true we won't make it + + + align:start position:0% +path where X2 is true we won't make it +because this uh piece will already have + + align:start position:0% +because this uh piece will already have + + + align:start position:0% +because this uh piece will already have +been removed when we came through here + + align:start position:0% +been removed when we came through here + + + align:start position:0% +been removed when we came through here +and so if we try to take this path we'll + + align:start position:0% +and so if we try to take this path we'll + + + align:start position:0% +and so if we try to take this path we'll +get stuck here there won't be any piece + + align:start position:0% +get stuck here there won't be any piece + + + align:start position:0% +get stuck here there won't be any piece +above us okay as long as that didn't + + align:start position:0% +above us okay as long as that didn't + + + align:start position:0% +above us okay as long as that didn't +happen as long as this this row was not + + align:start position:0% +happen as long as this this row was not + + + align:start position:0% +happen as long as this this row was not +chosen then we can take this column and + + align:start position:0% +chosen then we can take this column and + + + align:start position:0% +chosen then we can take this column and +just make it all the way up to the top + + align:start position:0% +just make it all the way up to the top + + + align:start position:0% +just make it all the way up to the top +so we're going to be able to take one of + + align:start position:0% +so we're going to be able to take one of + + + align:start position:0% +so we're going to be able to take one of +these three paths if and only if at + + align:start position:0% +these three paths if and only if at + + + align:start position:0% +these three paths if and only if at +least one of these things is true that's + + align:start position:0% +least one of these things is true that's + + + align:start position:0% +least one of these things is true that's +the first Clause uh then we do the same + + align:start position:0% +the first Clause uh then we do the same + + + align:start position:0% +the first Clause uh then we do the same +thing for the second clause and if all + + align:start position:0% +thing for the second clause and if all + + + align:start position:0% +thing for the second clause and if all +the Clauses are true we will be able to + + align:start position:0% +the Clauses are true we will be able to + + + align:start position:0% +the Clauses are true we will be able to +get here and then we can jump down and + + align:start position:0% +get here and then we can jump down and + + + align:start position:0% +get here and then we can jump down and +get to the Finish Line and win in one + + align:start position:0% +get to the Finish Line and win in one + + + align:start position:0% +get to the Finish Line and win in one +move one + + align:start position:0% +move one + + + align:start position:0% +move one +move okay so that's uh m one is MP + + align:start position:0% +move okay so that's uh m one is MP + + + align:start position:0% +move okay so that's uh m one is MP +complete uh I have one other example of + + align:start position:0% +complete uh I have one other example of + + + align:start position:0% +complete uh I have one other example of +a mate one result it's actually not a + + align:start position:0% +a mate one result it's actually not a + + + align:start position:0% +a mate one result it's actually not a +hardness result but it's kind of fun so + + align:start position:0% +hardness result but it's kind of fun so + + + align:start position:0% +hardness result but it's kind of fun so +I thought I would talk about a non + + align:start position:0% +I thought I would talk about a non + + + align:start position:0% +I thought I would talk about a non +hardness result for once which is + + align:start position:0% +hardness result for once which is + + + align:start position:0% +hardness result for once which is +Checkers Checkers is another game where + + align:start position:0% +Checkers Checkers is another game where + + + align:start position:0% +Checkers Checkers is another game where +in one move you can do a lot of jumps + + align:start position:0% +in one move you can do a lot of jumps + + + align:start position:0% +in one move you can do a lot of jumps +especially if you have a king uh then + + align:start position:0% +especially if you have a king uh then + + + align:start position:0% +especially if you have a king uh then +you can potentially win and by killing a + + align:start position:0% +you can potentially win and by killing a + + + align:start position:0% +you can potentially win and by killing a +lot of pieces all at once and this is + + align:start position:0% +lot of pieces all at once and this is + + + align:start position:0% +lot of pieces all at once and this is +considered back in 1978 this is the same + + align:start position:0% +considered back in 1978 this is the same + + + align:start position:0% +considered back in 1978 this is the same +paper that proves Checkers is X time + + align:start position:0% +paper that proves Checkers is X time + + + align:start position:0% +paper that proves Checkers is X time +complete which we will get to at some + + align:start position:0% +complete which we will get to at some + + + align:start position:0% +complete which we will get to at some +point uh but for now let's think about + + align:start position:0% +point uh but for now let's think about + + + align:start position:0% +point uh but for now let's think about +the main one problem this turns out to + + align:start position:0% +the main one problem this turns out to + + + align:start position:0% +the main one problem this turns out to +be easy unlike + + align:start position:0% +be easy unlike + + + align:start position:0% +be easy unlike +football so uh Checkers I assume you've + + align:start position:0% +football so uh Checkers I assume you've + + + align:start position:0% +football so uh Checkers I assume you've +all played Checkers you can only move + + align:start position:0% +all played Checkers you can only move + + + align:start position:0% +all played Checkers you can only move +diagonally on the black squares um so + + align:start position:0% +diagonally on the black squares um so + + + align:start position:0% +diagonally on the black squares um so +you can recast that into an orthogonal + + align:start position:0% +you can recast that into an orthogonal + + + align:start position:0% +you can recast that into an orthogonal +problem where the pieces can only move + + align:start position:0% +problem where the pieces can only move + + + align:start position:0% +problem where the pieces can only move +orthogonally up uh or or right or vice + + align:start position:0% +orthogonally up uh or or right or vice + + + align:start position:0% +orthogonally up uh or or right or vice +versa except King pieces they can just + + align:start position:0% +versa except King pieces they can just + + + align:start position:0% +versa except King pieces they can just +move orthogonally and the interesting + + align:start position:0% +move orthogonally and the interesting + + + align:start position:0% +move orthogonally and the interesting +part is when you can jump over a piece + + align:start position:0% +part is when you can jump over a piece + + + align:start position:0% +part is when you can jump over a piece +of another color so if there was a black + + align:start position:0% +of another color so if there was a black + + + align:start position:0% +of another color so if there was a black +piece here this one can jump over um and + + align:start position:0% +piece here this one can jump over um and + + + align:start position:0% +piece here this one can jump over um and +in general if you have a sequence of + + align:start position:0% +in general if you have a sequence of + + + align:start position:0% +in general if you have a sequence of +jumps you can make then you can do all + + align:start position:0% +jumps you can make then you can do all + + + align:start position:0% +jumps you can make then you can do all +of them at once so the problem looks + + align:start position:0% +of them at once so the problem looks + + + align:start position:0% +of them at once so the problem looks +something like this if you have a black + + align:start position:0% +something like this if you have a black + + + align:start position:0% +something like this if you have a black +piece and let's say black to move uh if + + align:start position:0% +piece and let's say black to move uh if + + + align:start position:0% +piece and let's say black to move uh if +there are a bunch of white pieces you + + align:start position:0% +there are a bunch of white pieces you + + + align:start position:0% +there are a bunch of white pieces you +can jump over them um and the key thing + + align:start position:0% +can jump over them um and the key thing + + + align:start position:0% +can jump over them um and the key thing +to notice again as soon as you jump over + + align:start position:0% +to notice again as soon as you jump over + + + align:start position:0% +to notice again as soon as you jump over +a piece it disappears so you can't reuse + + align:start position:0% +a piece it disappears so you can't reuse + + + align:start position:0% +a piece it disappears so you can't reuse +it in the same move or I guess you can't + + align:start position:0% +it in the same move or I guess you can't + + + align:start position:0% +it in the same move or I guess you can't +reuse it in general um the key thing is + + align:start position:0% +reuse it in general um the key thing is + + + align:start position:0% +reuse it in general um the key thing is +that the jumps preserve the parity the + + align:start position:0% +that the jumps preserve the parity the + + + align:start position:0% +that the jumps preserve the parity the +even or oddness of of both your x + + align:start position:0% +even or oddness of of both your x + + + align:start position:0% +even or oddness of of both your x +coordinate and your y-coordinate so + + align:start position:0% +coordinate and your y-coordinate so + + + align:start position:0% +coordinate and your y-coordinate so +you're moving around on this reduced + + align:start position:0% +you're moving around on this reduced + + + align:start position:0% +you're moving around on this reduced +grid and so you can take a picture like + + align:start position:0% +grid and so you can take a picture like + + + align:start position:0% +grid and so you can take a picture like +this and turn it into a graph where the + + align:start position:0% +this and turn it into a graph where the + + + align:start position:0% +this and turn it into a graph where the +potential positions for you uh which are + + align:start position:0% +potential positions for you uh which are + + + align:start position:0% +potential positions for you uh which are +drawn with this kind of pattern even + + align:start position:0% +drawn with this kind of pattern even + + + align:start position:0% +drawn with this kind of pattern even +same uh par of of uh rows and columns uh + + align:start position:0% +same uh par of of uh rows and columns uh + + + align:start position:0% +same uh par of of uh rows and columns uh +you can make those the vertices of your + + align:start position:0% +you can make those the vertices of your + + + align:start position:0% +you can make those the vertices of your +graph and then there's an edge between + + align:start position:0% +graph and then there's an edge between + + + align:start position:0% +graph and then there's an edge between +them if there's a white uh Stone in + + align:start position:0% +them if there's a white uh Stone in + + + align:start position:0% +them if there's a white uh Stone in +between that you could jump + + align:start position:0% +between that you could jump + + + align:start position:0% +between that you could jump +over so then given this graph the + + align:start position:0% +over so then given this graph the + + + align:start position:0% +over so then given this graph the +question is can you visit all of the + + align:start position:0% +question is can you visit all of the + + + align:start position:0% +question is can you visit all of the +edges of the graph with a single path + + align:start position:0% +edges of the graph with a single path + + + align:start position:0% +edges of the graph with a single path +and that is the oiler tour problem or + + align:start position:0% +and that is the oiler tour problem or + + + align:start position:0% +and that is the oiler tour problem or +the oiler path problem and it's easy to + + align:start position:0% +the oiler path problem and it's easy to + + + align:start position:0% +the oiler path problem and it's easy to +solve that in polinomial time you look + + align:start position:0% +solve that in polinomial time you look + + + align:start position:0% +solve that in polinomial time you look +for odd degree vertices there should be + + align:start position:0% +for odd degree vertices there should be + + + align:start position:0% +for odd degree vertices there should be +at most two of them and you better be at + + align:start position:0% +at most two of them and you better be at + + + align:start position:0% +at most two of them and you better be at +one of + + align:start position:0% +one of + + + align:start position:0% +one of +them uh or there's zero of them then + + align:start position:0% +them uh or there's zero of them then + + + align:start position:0% +them uh or there's zero of them then +you're happy so that's how to solve mate + + align:start position:0% +you're happy so that's how to solve mate + + + align:start position:0% +you're happy so that's how to solve mate +and one and Checkers in case you ever + + align:start position:0% +and one and Checkers in case you ever + + + align:start position:0% +and one and Checkers in case you ever +get to those difficult Checkers end + + align:start position:0% +get to those difficult Checkers end + + + align:start position:0% +get to those difficult Checkers end +games then now you can decide how to win + + align:start position:0% +games then now you can decide how to win + + + align:start position:0% +games then now you can decide how to win +or not in one move two moves is left to + + align:start position:0% +or not in one move two moves is left to + + + align:start position:0% +or not in one move two moves is left to +you all right um so next topic is uh + + align:start position:0% +you all right um so next topic is uh + + + align:start position:0% +you all right um so next topic is uh +called Crypt rhythms this is comes from + + align:start position:0% +called Crypt rhythms this is comes from + + + align:start position:0% +called Crypt rhythms this is comes from +the recreational math world and they're + + align:start position:0% +the recreational math world and they're + + + align:start position:0% +the recreational math world and they're +kind of fun you've probably seen this + + align:start position:0% +kind of fun you've probably seen this + + + align:start position:0% +kind of fun you've probably seen this +you may have seen this one if you've + + align:start position:0% +you may have seen this one if you've + + + align:start position:0% +you may have seen this one if you've +seen any Crypt Rhythm uh it's a classic + + align:start position:0% +seen any Crypt Rhythm uh it's a classic + + + align:start position:0% +seen any Crypt Rhythm uh it's a classic +goes back to 1979 from this book by + + align:start position:0% +goes back to 1979 from this book by + + + align:start position:0% +goes back to 1979 from this book by +madaki + + align:start position:0% +madaki + + + align:start position:0% +madaki +uh and the idea is this is an arithmetic + + align:start position:0% +uh and the idea is this is an arithmetic + + + align:start position:0% +uh and the idea is this is an arithmetic +formula Send Plus more equals money and + + align:start position:0% +formula Send Plus more equals money and + + + align:start position:0% +formula Send Plus more equals money and +each of these letters represents a digit + + align:start position:0% +each of these letters represents a digit + + + align:start position:0% +each of these letters represents a digit +0 through N9 and so the two M's + + align:start position:0% +0 through N9 and so the two M's + + + align:start position:0% +0 through N9 and so the two M's +represent the same digit and so on the + + align:start position:0% +represent the same digit and so on the + + + align:start position:0% +represent the same digit and so on the +two n's represent the same digit the two + + align:start position:0% +two n's represent the same digit the two + + + align:start position:0% +two n's represent the same digit the two +o's represent the same digit and + + align:start position:0% +o's represent the same digit and + + + align:start position:0% +o's represent the same digit and +furthermore m is different from o is + + align:start position:0% +furthermore m is different from o is + + + align:start position:0% +furthermore m is different from o is +different from R so it's it's a bje + + align:start position:0% +different from R so it's it's a bje + + + align:start position:0% +different from R so it's it's a bje +between the letters that appear in this + + align:start position:0% +between the letters that appear in this + + + align:start position:0% +between the letters that appear in this +puzzle and some subset of 0 through 9 + + align:start position:0% +puzzle and some subset of 0 through 9 + + + align:start position:0% +puzzle and some subset of 0 through 9 +and actually has a unique solution uh + + align:start position:0% +and actually has a unique solution uh + + + align:start position:0% +and actually has a unique solution uh +this is it you could verify it but I'll + + align:start position:0% +this is it you could verify it but I'll + + + align:start position:0% +this is it you could verify it but I'll +leave it as a puzzle so don't look at + + align:start position:0% +leave it as a puzzle so don't look at + + + align:start position:0% +leave it as a puzzle so don't look at +that too long in case you want to solve + + align:start position:0% +that too long in case you want to solve + + + align:start position:0% +that too long in case you want to solve +it um it is doable but you know the + + align:start position:0% +it um it is doable but you know the + + + align:start position:0% +it um it is doable but you know the +tricky part of things like the carries + + align:start position:0% +tricky part of things like the carries + + + align:start position:0% +tricky part of things like the carries +in the addition which make it not just a + + align:start position:0% +in the addition which make it not just a + + + align:start position:0% +in the addition which make it not just a +a simple linear system to solve and in + + align:start position:0% +a simple linear system to solve and in + + + align:start position:0% +a simple linear system to solve and in +fact these puzzles uh generalize to an + + align:start position:0% +fact these puzzles uh generalize to an + + + align:start position:0% +fact these puzzles uh generalize to an +arbitrary base are and be complete if + + align:start position:0% +arbitrary base are and be complete if + + + align:start position:0% +arbitrary base are and be complete if +you do it in uh base 10 then there's + + align:start position:0% +you do it in uh base 10 then there's + + + align:start position:0% +you do it in uh base 10 then there's +only at most 10 factorial possible + + align:start position:0% +only at most 10 factorial possible + + + align:start position:0% +only at most 10 factorial possible +solutions so that's constant and that's + + align:start position:0% +solutions so that's constant and that's + + + align:start position:0% +solutions so that's constant and that's +considered fast and indeed in real + + align:start position:0% +considered fast and indeed in real + + + align:start position:0% +considered fast and indeed in real +computers you can solve 10 factorial + + align:start position:0% +computers you can solve 10 factorial + + + align:start position:0% +computers you can solve 10 factorial +reasonably um so uh for generalized base + + align:start position:0% +reasonably um so uh for generalized base + + + align:start position:0% +reasonably um so uh for generalized base +here is a proof this is actually David + + align:start position:0% +here is a proof this is actually David + + + align:start position:0% +here is a proof this is actually David +Epstein who was a co-author in the + + align:start position:0% +Epstein who was a co-author in the + + + align:start position:0% +Epstein who was a co-author in the +previous result this is his first Theory + + align:start position:0% +previous result this is his first Theory + + + align:start position:0% +previous result this is his first Theory +paper on cak + + align:start position:0% +paper on cak + + + align:start position:0% +paper on cak +news and uh proved that it's strongly NP + + align:start position:0% +news and uh proved that it's strongly NP + + + align:start position:0% +news and uh proved that it's strongly NP +complete meaning even if the base is + + align:start position:0% +complete meaning even if the base is + + + align:start position:0% +complete meaning even if the base is +polinomial the problem is NP hard and it + + align:start position:0% +polinomial the problem is NP hard and it + + + align:start position:0% +polinomial the problem is NP hard and it +looks really + + align:start position:0% +looks really + + + align:start position:0% +looks really +messy uh but actually it's fairly simple + + align:start position:0% +messy uh but actually it's fairly simple + + + align:start position:0% +messy uh but actually it's fairly simple +so so + + align:start position:0% +so so + + + align:start position:0% +so so +um let me start with this gadget this is + + align:start position:0% +um let me start with this gadget this is + + + align:start position:0% +um let me start with this gadget this is +an easy one uh so there's no notion of + + align:start position:0% +an easy one uh so there's no notion of + + + align:start position:0% +an easy one uh so there's no notion of +zero or one in this gadget but uh zero + + align:start position:0% +zero or one in this gadget but uh zero + + + align:start position:0% +zero or one in this gadget but uh zero +is just a letter and one is just a + + align:start position:0% +is just a letter and one is just a + + + align:start position:0% +is just a letter and one is just a +letter but at with this gadget in place + + align:start position:0% +letter but at with this gadget in place + + + align:start position:0% +letter but at with this gadget in place +Z is zero and one is one because zero is + + align:start position:0% +Z is zero and one is one because zero is + + + align:start position:0% +Z is zero and one is one because zero is +the only possible digit when you add it + + align:start position:0% +the only possible digit when you add it + + + align:start position:0% +the only possible digit when you add it +with yourself you get it again okay it + + align:start position:0% +with yourself you get it again okay it + + + align:start position:0% +with yourself you get it again okay it +is the identity in in additive ring so + + align:start position:0% +is the identity in in additive ring so + + + align:start position:0% +is the identity in in additive ring so +that force is Zer to be zero and and + + align:start position:0% +that force is Zer to be zero and and + + + align:start position:0% +that force is Zer to be zero and and +then here um we're adding p with p p are + + align:start position:0% +then here um we're adding p with p p are + + + align:start position:0% +then here um we're adding p with p p are +just arbitrary things sort of don't care + + align:start position:0% +just arbitrary things sort of don't care + + + align:start position:0% +just arbitrary things sort of don't care +what they are we get something q and + + align:start position:0% +what they are we get something q and + + + align:start position:0% +what they are we get something q and +over here we add Z to zero and we get + + align:start position:0% +over here we add Z to zero and we get + + + align:start position:0% +over here we add Z to zero and we get +one that's only going to be possible if + + align:start position:0% +one that's only going to be possible if + + + align:start position:0% +one that's only going to be possible if +there's a carry in this column and + + align:start position:0% +there's a carry in this column and + + + align:start position:0% +there's a carry in this column and +Carries can be only one they can be zero + + align:start position:0% +Carries can be only one they can be zero + + + align:start position:0% +Carries can be only one they can be zero +or one so that forces we know it's not + + align:start position:0% +or one so that forces we know it's not + + + align:start position:0% +or one so that forces we know it's not +zero because one is different from zero + + align:start position:0% +zero because one is different from zero + + + align:start position:0% +zero because one is different from zero +therefore one is one okay symbol one is + + align:start position:0% +therefore one is one okay symbol one is + + + align:start position:0% +therefore one is one okay symbol one is +the value one the number one all right + + align:start position:0% +the value one the number one all right + + + align:start position:0% +the value one the number one all right +so that gives us some infrastructure and + + align:start position:0% +so that gives us some infrastructure and + + + align:start position:0% +so that gives us some infrastructure and +the zeros are really helpful CU it lets + + align:start position:0% +the zeros are really helpful CU it lets + + + align:start position:0% +the zeros are really helpful CU it lets +us space out gadgets and guarantee that + + align:start position:0% +us space out gadgets and guarantee that + + + align:start position:0% +us space out gadgets and guarantee that +there's no carry between them this is + + align:start position:0% +there's no carry between them this is + + + align:start position:0% +there's no carry between them this is +supposed to be a variable Gadget there's + + align:start position:0% +supposed to be a variable Gadget there's + + + align:start position:0% +supposed to be a variable Gadget there's +uh + + align:start position:0% +uh + + + align:start position:0% +uh +VI and there's VI bar so let's see what + + align:start position:0% +VI and there's VI bar so let's see what + + + align:start position:0% +VI and there's VI bar so let's see what +what happens let's do the VI Part first + + align:start position:0% +what happens let's do the VI Part first + + + align:start position:0% +what happens let's do the VI Part first +so this this formula says that bi equals + + align:start position:0% +so this this formula says that bi equals + + + align:start position:0% +so this this formula says that bi equals +twice Ai and there's guaranteed to be no + + align:start position:0% +twice Ai and there's guaranteed to be no + + + align:start position:0% +twice Ai and there's guaranteed to be no +carry because of this this is a little + + align:start position:0% +carry because of this this is a little + + + align:start position:0% +carry because of this this is a little +tricky we add Yi to Yi we get zi so + + align:start position:0% +tricky we add Yi to Yi we get zi so + + + align:start position:0% +tricky we add Yi to Yi we get zi so +there may be a carry or not + + align:start position:0% +there may be a carry or not + + + align:start position:0% +there may be a carry or not +here then we add bi to bi and we get VI + + align:start position:0% +here then we add bi to bi and we get VI + + + align:start position:0% +here then we add bi to bi and we get VI +so VI is going to be 2 * bi Plus either + + align:start position:0% +so VI is going to be 2 * bi Plus either + + + align:start position:0% +so VI is going to be 2 * bi Plus either +zero or one that's going to be our + + align:start position:0% +zero or one that's going to be our + + + align:start position:0% +zero or one that's going to be our +binary choice we can set up the Yi to + + align:start position:0% +binary choice we can set up the Yi to + + + align:start position:0% +binary choice we can set up the Yi to +either carry or not we'll call that c c + + align:start position:0% +either carry or not we'll call that c c + + + align:start position:0% +either carry or not we'll call that c c +in this formulation C is the carry in + + align:start position:0% +in this formulation C is the carry in + + + align:start position:0% +in this formulation C is the carry in +that + + align:start position:0% +that + + + align:start position:0% +that +operation + + align:start position:0% +operation + + + align:start position:0% +operation +uh okay and bi is 2 * AI so this is four + + align:start position:0% +uh okay and bi is 2 * AI so this is four + + + align:start position:0% +uh okay and bi is 2 * AI so this is four +time AI plus + + align:start position:0% +time AI plus + + + align:start position:0% +time AI plus +C which is01 and what we're going to + + align:start position:0% +C which is01 and what we're going to + + + align:start position:0% +C which is01 and what we're going to +think about is uh modulo 4 this is + + align:start position:0% +think about is uh modulo 4 this is + + + align:start position:0% +think about is uh modulo 4 this is +congruent to + + align:start position:0% +congruent to + + + align:start position:0% +congruent to +C so we're going to treat all of our + + align:start position:0% +C so we're going to treat all of our + + + align:start position:0% +C so we're going to treat all of our +variable assignments modu of 4 and + + align:start position:0% +variable assignments modu of 4 and + + + align:start position:0% +variable assignments modu of 4 and +they're always going to be Z or one the + + align:start position:0% +they're always going to be Z or one the + + + align:start position:0% +they're always going to be Z or one the +claim is VI became this and the claim is + + align:start position:0% +claim is VI became this and the claim is + + + align:start position:0% +claim is VI became this and the claim is +that this part makes VI bar the + + align:start position:0% +that this part makes VI bar the + + + align:start position:0% +that this part makes VI bar the +opposite and you can work through the + + align:start position:0% +opposite and you can work through the + + + align:start position:0% +opposite and you can work through the +arithmetic uh as I did in the notes um + + align:start position:0% +arithmetic uh as I did in the notes um + + + align:start position:0% +arithmetic uh as I did in the notes um +you end up VI bar has to be um 4 * + + align:start position:0% +you end up VI bar has to be um 4 * + + + align:start position:0% +you end up VI bar has to be um 4 * +something which is CI so we don't sort + + align:start position:0% +something which is CI so we don't sort + + + align:start position:0% +something which is CI so we don't sort +of don't care what that is uh we'll set + + align:start position:0% +of don't care what that is uh we'll set + + + align:start position:0% +of don't care what that is uh we'll set +it at the very end uh plus 3 C + 1 if C + + align:start position:0% +it at the very end uh plus 3 C + 1 if C + + + align:start position:0% +it at the very end uh plus 3 C + 1 if C +is 1 this is four and this becomes zero + + align:start position:0% +is 1 this is four and this becomes zero + + + align:start position:0% +is 1 this is four and this becomes zero +uh if C is zero this becomes one mod 4 + + align:start position:0% +uh if C is zero this becomes one mod 4 + + + align:start position:0% +uh if C is zero this becomes one mod 4 +so uh in general it's 1 minus C it's the + + align:start position:0% +so uh in general it's 1 minus C it's the + + + align:start position:0% +so uh in general it's 1 minus C it's the +opposite Choice from what VI was uh that + + align:start position:0% +opposite Choice from what VI was uh that + + + align:start position:0% +opposite Choice from what VI was uh that +becomes VI bar so that's cool we've got + + align:start position:0% +becomes VI bar so that's cool we've got + + + align:start position:0% +becomes VI bar so that's cool we've got +VI and we've got VI bar we can duplicate + + align:start position:0% +VI and we've got VI bar we can duplicate + + + align:start position:0% +VI and we've got VI bar we can duplicate +our variables for free because we can + + align:start position:0% +our variables for free because we can + + + align:start position:0% +our variables for free because we can +just use that same letter VI in many + + align:start position:0% +just use that same letter VI in many + + + align:start position:0% +just use that same letter VI in many +different places and then we just need a + + align:start position:0% +different places and then we just need a + + + align:start position:0% +different places and then we just need a +clause + + align:start position:0% +clause + + + align:start position:0% +clause +Gadget um + + align:start position:0% +Gadget um + + + align:start position:0% +Gadget um +and so uh the work is kind of similar + + align:start position:0% +and so uh the work is kind of similar + + + align:start position:0% +and so uh the work is kind of similar +similar kind of tricks we add VI fi to + + align:start position:0% +similar kind of tricks we add VI fi to + + + align:start position:0% +similar kind of tricks we add VI fi to +itself we get GI we add GI to itself we + + align:start position:0% +itself we get GI we add GI to itself we + + + align:start position:0% +itself we get GI we add GI to itself we +get hi so at this point we have four + + align:start position:0% +get hi so at this point we have four + + + align:start position:0% +get hi so at this point we have four +times + + align:start position:0% +times + + + align:start position:0% +times +fi uh plus possibly one carry this wi + + align:start position:0% +fi uh plus possibly one carry this wi + + + align:start position:0% +fi uh plus possibly one carry this wi +might carry or not so uh we get + + align:start position:0% + + + + align:start position:0% + +hi is 4 * + + align:start position:0% +hi is 4 * + + + align:start position:0% +hi is 4 * +fi plus + + align:start position:0% +fi plus + + + align:start position:0% +fi plus +01 then we add hi to one and we get TI + + align:start position:0% +01 then we add hi to one and we get TI + + + align:start position:0% +01 then we add hi to one and we get TI +plus there might be a carry from this + + align:start position:0% +plus there might be a carry from this + + + align:start position:0% +plus there might be a carry from this +column so that's + + align:start position:0% +column so that's + + + align:start position:0% +column so that's +TI is going to be hi + 1 plus a + + align:start position:0% +TI is going to be hi + 1 plus a + + + align:start position:0% +TI is going to be hi + 1 plus a +potential + + align:start position:0% +potential + + + align:start position:0% +potential +carry hi is this thing so we end up with + + align:start position:0% +carry hi is this thing so we end up with + + + align:start position:0% +carry hi is this thing so we end up with +4 * + + align:start position:0% +4 * + + + align:start position:0% +4 * +fi + + + align:start position:0% +fi + + + + align:start position:0% +fi + +1+ uh 0 or one or two depending on how + + align:start position:0% +1+ uh 0 or one or two depending on how + + + align:start position:0% +1+ uh 0 or one or two depending on how +many carries we've had total which is 4 + + align:start position:0% +many carries we've had total which is 4 + + + align:start position:0% +many carries we've had total which is 4 +* fi plus one or 2 or + + align:start position:0% +* fi plus one or 2 or + + + align:start position:0% +* fi plus one or 2 or +three and modul of 4 that is one or two + + align:start position:0% +three and modul of 4 that is one or two + + + align:start position:0% +three and modul of 4 that is one or two +or three this is going to be the number + + align:start position:0% +or three this is going to be the number + + + align:start position:0% +or three this is going to be the number +of true variables in our Clause cuz in + + align:start position:0% +of true variables in our Clause cuz in + + + align:start position:0% +of true variables in our Clause cuz in +the end we just add VI plus VB we get + + align:start position:0% +the end we just add VI plus VB we get + + + align:start position:0% +the end we just add VI plus VB we get +this thing we add add VC for our three + + align:start position:0% +this thing we add add VC for our three + + + align:start position:0% +this thing we add add VC for our three +variables VA a b and c we get + + align:start position:0% +variables VA a b and c we get + + + align:start position:0% +variables VA a b and c we get +TI and TI was that + + align:start position:0% +TI and TI was that + + + align:start position:0% +TI and TI was that +thing so if we just think about things + + align:start position:0% +thing so if we just think about things + + + align:start position:0% +thing so if we just think about things +modul 4 that means V VA plus VB plus VC + + align:start position:0% +modul 4 that means V VA plus VB plus VC + + + align:start position:0% +modul 4 that means V VA plus VB plus VC +should be one two or three mod + + align:start position:0% +should be one two or three mod + + + align:start position:0% +should be one two or three mod +four okay now the reason we have this + + align:start position:0% +four okay now the reason we have this + + + align:start position:0% +four okay now the reason we have this +junk and the + + align:start position:0% +junk and the + + + align:start position:0% +junk and the +junks uh well okay there's there's the + + align:start position:0% +junks uh well okay there's there's the + + + align:start position:0% +junks uh well okay there's there's the +not modulo 4 part the part when you + + align:start position:0% +not modulo 4 part the part when you + + + align:start position:0% +not modulo 4 part the part when you +divide by four that's sort of tricky uh + + align:start position:0% +divide by four that's sort of tricky uh + + + align:start position:0% +divide by four that's sort of tricky uh +but at this point at least you should be + + align:start position:0% +but at this point at least you should be + + + align:start position:0% +but at this point at least you should be +convinced that um if there's a solution + + align:start position:0% +convinced that um if there's a solution + + + align:start position:0% +convinced that um if there's a solution +to this problem then there must be a + + align:start position:0% +to this problem then there must be a + + + align:start position:0% +to this problem then there must be a +solution to the original Three side + + align:start position:0% +solution to the original Three side + + + align:start position:0% +solution to the original Three side +instance the reverse is less clear if + + align:start position:0% +instance the reverse is less clear if + + + align:start position:0% +instance the reverse is less clear if +you have a solution to the three side + + align:start position:0% +you have a solution to the three side + + + align:start position:0% +you have a solution to the three side +instance you have to be able to set all + + align:start position:0% +instance you have to be able to set all + + + align:start position:0% +instance you have to be able to set all +these variables to make everything work + + align:start position:0% +these variables to make everything work + + + align:start position:0% +these variables to make everything work +out that's a little more tedious um for + + align:start position:0% +out that's a little more tedious um for + + + align:start position:0% +out that's a little more tedious um for +fun I mean this is an old proof 1987 uh + + align:start position:0% +fun I mean this is an old proof 1987 uh + + + align:start position:0% +fun I mean this is an old proof 1987 uh +and I was just looking at it uh again + + align:start position:0% +and I was just looking at it uh again + + + align:start position:0% +and I was just looking at it uh again +today I think and or I think this is + + align:start position:0% +today I think and or I think this is + + + align:start position:0% +today I think and or I think this is +yesterday I think I can simplify it a + + align:start position:0% +yesterday I think I can simplify it a + + + align:start position:0% +yesterday I think I can simplify it a +little bit instead of using regular + + align:start position:0% +little bit instead of using regular + + + align:start position:0% +little bit instead of using regular +three set where you have all these + + align:start position:0% +three set where you have all these + + + align:start position:0% +three set where you have all these +choices one two or three things are true + + align:start position:0% +choices one two or three things are true + + + align:start position:0% +choices one two or three things are true +if you use exactly one three set one and + + align:start position:0% +if you use exactly one three set one and + + + align:start position:0% +if you use exactly one three set one and +three Set uh it should be a lot easier + + align:start position:0% +three Set uh it should be a lot easier + + + align:start position:0% +three Set uh it should be a lot easier +so gadgets are smaller uh with one and + + align:start position:0% +so gadgets are smaller uh with one and + + + align:start position:0% +so gadgets are smaller uh with one and +three set we don't need negation so I + + align:start position:0% +three set we don't need negation so I + + + align:start position:0% +three set we don't need negation so I +just need the VI Part which we did + + align:start position:0% +just need the VI Part which we did + + + align:start position:0% +just need the VI Part which we did +explicitly over here so that's kind of + + align:start position:0% +explicitly over here so that's kind of + + + align:start position:0% +explicitly over here so that's kind of +nifty um and for exactly one threat we + + align:start position:0% +nifty um and for exactly one threat we + + + align:start position:0% +nifty um and for exactly one threat we +we don't need to have all those carries + + align:start position:0% +we don't need to have all those carries + + + align:start position:0% +we don't need to have all those carries +we just need to build four time + + align:start position:0% +we just need to build four time + + + align:start position:0% +we just need to build four time +something + + align:start position:0% +something + + + align:start position:0% +something +sorry that should be fi here uh we add + + align:start position:0% +sorry that should be fi here uh we add + + + align:start position:0% +sorry that should be fi here uh we add +fi to itself we add GI to itself so we + + align:start position:0% +fi to itself we add GI to itself so we + + + align:start position:0% +fi to itself we add GI to itself so we +here we have four * fi um and then we + + align:start position:0% +here we have four * fi um and then we + + + align:start position:0% +here we have four * fi um and then we +add one so this will be This Ti will be + + align:start position:0% +add one so this will be This Ti will be + + + align:start position:0% +add one so this will be This Ti will be +one mod 4 and then we add the variables + + align:start position:0% +one mod 4 and then we add the variables + + + align:start position:0% +one mod 4 and then we add the variables +up and we should get exactly one mod 4 + + align:start position:0% +up and we should get exactly one mod 4 + + + align:start position:0% +up and we should get exactly one mod 4 +now admittedly I haven't checked the + + align:start position:0% +now admittedly I haven't checked the + + + align:start position:0% +now admittedly I haven't checked the +second half of the proof with this + + align:start position:0% +second half of the proof with this + + + align:start position:0% +second half of the proof with this +construction but seems plausible this + + align:start position:0% +construction but seems plausible this + + + align:start position:0% +construction but seems plausible this +would be a somewhat simpler proof so + + align:start position:0% +would be a somewhat simpler proof so + + + align:start position:0% +would be a somewhat simpler proof so +shows you the power of all the different + + align:start position:0% +shows you the power of all the different + + + align:start position:0% +shows you the power of all the different +versions of threat we saw last + + align:start position:0% +versions of threat we saw last + + + align:start position:0% +versions of threat we saw last +class + + align:start position:0% +class + + + align:start position:0% +class +um now I can tell you a little bit about + + align:start position:0% +um now I can tell you a little bit about + + + align:start position:0% +um now I can tell you a little bit about +the other + + align:start position:0% + + + + align:start position:0% + +direction + + align:start position:0% +direction + + + align:start position:0% +direction +um I have some of the details written + + align:start position:0% +um I have some of the details written + + + align:start position:0% +um I have some of the details written +down here so the other direction is we + + align:start position:0% +down here so the other direction is we + + + align:start position:0% +down here so the other direction is we +need to check that if there's a + + align:start position:0% +need to check that if there's a + + + align:start position:0% +need to check that if there's a +satisfying assignment to threat or one + + align:start position:0% +satisfying assignment to threat or one + + + align:start position:0% +satisfying assignment to threat or one +and threat that we can actually + + align:start position:0% +and threat that we can actually + + + align:start position:0% +and threat that we can actually +construct these numbers uh that the base + + align:start position:0% +construct these numbers uh that the base + + + align:start position:0% +construct these numbers uh that the base +is only + + align:start position:0% +is only + + + align:start position:0% +is only +polinomial uh the trickiest part part is + + align:start position:0% +polinomial uh the trickiest part part is + + + align:start position:0% +polinomial uh the trickiest part part is +to get all of these numbers to be + + align:start position:0% +to get all of these numbers to be + + + align:start position:0% +to get all of these numbers to be +distinct from each + + align:start position:0% +distinct from each + + + align:start position:0% +distinct from each +other + + align:start position:0% +other + + + align:start position:0% +other +um what Bas you the base will be + + align:start position:0% +um what Bas you the base will be + + + align:start position:0% +um what Bas you the base will be +something like n + + align:start position:0% +something like n + + + align:start position:0% +something like n +cubed it turns out and uh I'll tell you + + align:start position:0% +cubed it turns out and uh I'll tell you + + + align:start position:0% +cubed it turns out and uh I'll tell you +one trick is we have all these AI b i + + align:start position:0% +one trick is we have all these AI b i + + + align:start position:0% +one trick is we have all these AI b i +and CIS we can guarantee they are all + + align:start position:0% +and CIS we can guarantee they are all + + + align:start position:0% +and CIS we can guarantee they are all +different from each other that all the + + align:start position:0% +different from each other that all the + + + align:start position:0% +different from each other that all the +A's are different from all the B's or + + align:start position:0% +A's are different from all the B's or + + + align:start position:0% +A's are different from all the B's or +different from all the C's uh by + + align:start position:0% +different from all the C's uh by + + + align:start position:0% +different from all the C's uh by +distinguishing by saying all A's get + + align:start position:0% +distinguishing by saying all A's get + + + align:start position:0% +distinguishing by saying all A's get +this right all A's will be 2 34 66 or 98 + + align:start position:0% +this right all A's will be 2 34 66 or 98 + + + align:start position:0% +this right all A's will be 2 34 66 or 98 +mod + + align:start position:0% +mod + + + align:start position:0% +mod +128 and in general uh those are + + align:start position:0% +128 and in general uh those are + + + align:start position:0% +128 and in general uh those are +particular numbers set up to make this + + align:start position:0% +particular numbers set up to make this + + + align:start position:0% +particular numbers set up to make this +construction work out I didn't check + + align:start position:0% +construction work out I didn't check + + + align:start position:0% +construction work out I didn't check +them all but I believe them um in + + align:start position:0% +them all but I believe them um in + + + align:start position:0% +them all but I believe them um in +general we're going to distinguish all + + align:start position:0% +general we're going to distinguish all + + + align:start position:0% +general we're going to distinguish all +the letters by how they be how what they + + align:start position:0% +the letters by how they be how what they + + + align:start position:0% +the letters by how they be how what they +are mod 128 so given a number between 0 + + align:start position:0% +are mod 128 so given a number between 0 + + + align:start position:0% +are mod 128 so given a number between 0 +and 127 there's a unique letter of the + + align:start position:0% +and 127 there's a unique letter of the + + + align:start position:0% +and 127 there's a unique letter of the +regular English letter alphabet the A's + + align:start position:0% +regular English letter alphabet the A's + + + align:start position:0% +regular English letter alphabet the A's +the B's the Y's the Z's and so on uh + + align:start position:0% +the B's the Y's the Z's and so on uh + + + align:start position:0% +the B's the Y's the Z's and so on uh +that it is assigned to and I'll tell you + + align:start position:0% +that it is assigned to and I'll tell you + + + align:start position:0% +that it is assigned to and I'll tell you +in particular the + + align:start position:0% +in particular the + + + align:start position:0% +in particular the +vi and the vi bars are going to be I + + align:start position:0% +vi and the vi bars are going to be I + + + align:start position:0% +vi and the vi bars are going to be I +think eight or + + align:start position:0% +think eight or + + + align:start position:0% +think eight or +nine mod + + align:start position:0% + + + + align:start position:0% + +128 uh and the eight is if it's + + align:start position:0% +128 uh and the eight is if it's + + + align:start position:0% +128 uh and the eight is if it's +false and the nine is if it's true + + align:start position:0% +false and the nine is if it's true + + + align:start position:0% +false and the nine is if it's true +because remember modulo 4 we want this + + align:start position:0% +because remember modulo 4 we want this + + + align:start position:0% +because remember modulo 4 we want this +to be zero and we want this to be one so + + align:start position:0% +to be zero and we want this to be one so + + + align:start position:0% +to be zero and we want this to be one so +there's a bunch of choices like that + + align:start position:0% +there's a bunch of choices like that + + + align:start position:0% +there's a bunch of choices like that +some of them are unique we can always + + align:start position:0% +some of them are unique we can always + + + align:start position:0% +some of them are unique we can always +guarantee forget which ones the CIS are + + align:start position:0% +guarantee forget which ones the CIS are + + + align:start position:0% +guarantee forget which ones the CIS are +all something mod 128 so the mod 128 + + align:start position:0% +all something mod 128 so the mod 128 + + + align:start position:0% +all something mod 128 so the mod 128 +will tell you sort of what letter of the + + align:start position:0% +will tell you sort of what letter of the + + + align:start position:0% +will tell you sort of what letter of the +English alphabet it is and then it's a + + align:start position:0% +English alphabet it is and then it's a + + + align:start position:0% +English alphabet it is and then it's a +matter of deciding the high order bits + + align:start position:0% +matter of deciding the high order bits + + + align:start position:0% +matter of deciding the high order bits +uh your number divided by 128 and take + + align:start position:0% +uh your number divided by 128 and take + + + align:start position:0% +uh your number divided by 128 and take +the floor uh what that is we set to make + + align:start position:0% +the floor uh what that is we set to make + + + align:start position:0% +the floor uh what that is we set to make +everybody + + align:start position:0% +everybody + + + align:start position:0% +everybody +distinct and um the heart of the proof I + + align:start position:0% +distinct and um the heart of the proof I + + + align:start position:0% +distinct and um the heart of the proof I +will say is to make sure that the uh + + align:start position:0% +will say is to make sure that the uh + + + align:start position:0% +will say is to make sure that the uh +VIIs are all + + align:start position:0% +VIIs are all + + + align:start position:0% +VIIs are all +different um + + align:start position:0% +different um + + + align:start position:0% +different um +um or let's say that the ti are + + align:start position:0% +um or let's say that the ti are + + + align:start position:0% +um or let's say that the ti are +different so we have we have the + + align:start position:0% +different so we have we have the + + + align:start position:0% +different so we have we have the +variables here we're adding them up and + + align:start position:0% +variables here we're adding them up and + + + align:start position:0% +variables here we're adding them up and +we get TI and we need those all of the + + align:start position:0% +we get TI and we need those all of the + + + align:start position:0% +we get TI and we need those all of the +ti there's one TI per Clause we need + + align:start position:0% +ti there's one TI per Clause we need + + + align:start position:0% +ti there's one TI per Clause we need +them all to be different which means no + + align:start position:0% +them all to be different which means no + + + align:start position:0% +them all to be different which means no +matter which triple of VI we get we + + align:start position:0% +matter which triple of VI we get we + + + align:start position:0% +matter which triple of VI we get we +should get a different sum of the + + align:start position:0% +should get a different sum of the + + + align:start position:0% +should get a different sum of the +triples so this is a problem of uh set + + align:start position:0% +triples so this is a problem of uh set + + + align:start position:0% +triples so this is a problem of uh set +VI and VI Prime uh divided by + + align:start position:0% + + + + align:start position:0% + +128 so + + align:start position:0% +128 so + + + align:start position:0% +128 so +that VI plus + + align:start position:0% +that VI plus + + + align:start position:0% +that VI plus +VJ plus + + align:start position:0% +VJ plus + + + align:start position:0% +VJ plus +VK uh are all + + align:start position:0% + + + + align:start position:0% + +distinct and at this point epin says oh + + align:start position:0% +distinct and at this point epin says oh + + + align:start position:0% +distinct and at this point epin says oh +there's a result by Bose and Chala from + + align:start position:0% +there's a result by Bose and Chala from + + + align:start position:0% +there's a result by Bose and Chala from +1959 that says you can always choose + + align:start position:0% +1959 that says you can always choose + + + align:start position:0% +1959 that says you can always choose +these guys um if there's n of them that + + align:start position:0% +these guys um if there's n of them that + + + align:start position:0% +these guys um if there's n of them that +you need to choose then n cubed + + align:start position:0% +you need to choose then n cubed + + + align:start position:0% +you need to choose then n cubed +different integers suffice to make this + + align:start position:0% +different integers suffice to make this + + + align:start position:0% +different integers suffice to make this +true uh that's if you know the + + align:start position:0% +true uh that's if you know the + + + align:start position:0% +true uh that's if you know the +literature super well but there's an + + align:start position:0% +literature super well but there's an + + + align:start position:0% +literature super well but there's an +easy proof uh that polinomial is enough + + align:start position:0% +easy proof uh that polinomial is enough + + + align:start position:0% +easy proof uh that polinomial is enough +here and those of you who are in + + align:start position:0% +here and those of you who are in + + + align:start position:0% +here and those of you who are in +6851 should be able to construct one + + align:start position:0% +6851 should be able to construct one + + + align:start position:0% +6851 should be able to construct one +because this is essentially Fusion trees + + align:start position:0% +because this is essentially Fusion trees + + + align:start position:0% +because this is essentially Fusion trees +uh but in general imagine that you've + + align:start position:0% +uh but in general imagine that you've + + + align:start position:0% +uh but in general imagine that you've +chosen um by + + align:start position:0% + + + + align:start position:0% + +induction I'll call them V less than I + + align:start position:0% +induction I'll call them V less than I + + + align:start position:0% +induction I'll call them V less than I +and Let's ignore the primes let's just + + align:start position:0% +and Let's ignore the primes let's just + + + align:start position:0% +and Let's ignore the primes let's just +say we've constructed all the things up + + align:start position:0% +say we've constructed all the things up + + + align:start position:0% +say we've constructed all the things up +to vus one and now we want to + + align:start position:0% +to vus one and now we want to + + + align:start position:0% +to vus one and now we want to +choose + + align:start position:0% +choose + + + align:start position:0% +choose +VI uh and it needs to + + align:start position:0% +VI uh and it needs to + + + align:start position:0% +VI uh and it needs to +avoid uh certain values I think if it + + align:start position:0% +avoid uh certain values I think if it + + + align:start position:0% +avoid uh certain values I think if it +avoids VJ plus + + align:start position:0% +avoids VJ plus + + + align:start position:0% +avoids VJ plus +VK minus v l minus VM minus + + align:start position:0% +VK minus v l minus VM minus + + + align:start position:0% +VK minus v l minus VM minus +VP for all j k l m p less than + + align:start position:0% +VP for all j k l m p less than + + + align:start position:0% +VP for all j k l m p less than +I then no triple should sum to any other + + align:start position:0% +I then no triple should sum to any other + + + align:start position:0% +I then no triple should sum to any other +triple because if we add uh I think I + + align:start position:0% +triple because if we add uh I think I + + + align:start position:0% +triple because if we add uh I think I +maybe I have those signs slightly off so + + align:start position:0% +maybe I have those signs slightly off so + + + align:start position:0% +maybe I have those signs slightly off so +I wanted + + align:start position:0% +I wanted + + + align:start position:0% +I wanted +to do + + align:start position:0% +to do + + + align:start position:0% +to do +this yeah so let's do one more plus okay + + align:start position:0% +this yeah so let's do one more plus okay + + + align:start position:0% +this yeah so let's do one more plus okay +so suppose I had an equation like this + + align:start position:0% +so suppose I had an equation like this + + + align:start position:0% +so suppose I had an equation like this +um I claim that's bad because if I move + + align:start position:0% +um I claim that's bad because if I move + + + align:start position:0% +um I claim that's bad because if I move +these guys over to the left left hand + + align:start position:0% +these guys over to the left left hand + + + align:start position:0% +these guys over to the left left hand +side that's a triple of V's that sums to + + align:start position:0% +side that's a triple of V's that sums to + + + align:start position:0% +side that's a triple of V's that sums to +another triple of V's so as long as I + + align:start position:0% +another triple of V's so as long as I + + + align:start position:0% +another triple of V's so as long as I +choose my new value V uh sorry this + + align:start position:0% +choose my new value V uh sorry this + + + align:start position:0% +choose my new value V uh sorry this +should be + + align:start position:0% +should be + + + align:start position:0% +should be +VI is the one I'm choosing as long as I + + align:start position:0% +VI is the one I'm choosing as long as I + + + align:start position:0% +VI is the one I'm choosing as long as I +choose VI to be + + align:start position:0% +choose VI to be + + + align:start position:0% +choose VI to be +different uh from all all such sums and + + align:start position:0% +different uh from all all such sums and + + + align:start position:0% +different uh from all all such sums and +they're only like less than n the 5th + + align:start position:0% +they're only like less than n the 5th + + + align:start position:0% +they're only like less than n the 5th +such + + align:start position:0% +such + + + align:start position:0% +such +sums because there're only n of these + + align:start position:0% +sums because there're only n of these + + + align:start position:0% +sums because there're only n of these +different things then uh I'm okay and so + + align:start position:0% +different things then uh I'm okay and so + + + align:start position:0% +different things then uh I'm okay and so +by pigeon hle Principle as long as I + + align:start position:0% +by pigeon hle Principle as long as I + + + align:start position:0% +by pigeon hle Principle as long as I +have a range that is at least n the 5th + + align:start position:0% +have a range that is at least n the 5th + + + align:start position:0% +have a range that is at least n the 5th +in size then I can always choose VI to + + align:start position:0% +in size then I can always choose VI to + + + align:start position:0% +in size then I can always choose VI to +avoid all those conflicts okay so that's + + align:start position:0% +avoid all those conflicts okay so that's + + + align:start position:0% +avoid all those conflicts okay so that's +a really easy proof that n the 5th is + + align:start position:0% +a really easy proof that n the 5th is + + + align:start position:0% +a really easy proof that n the 5th is +enough in fact n cubed is enough but + + align:start position:0% +enough in fact n cubed is enough but + + + align:start position:0% +enough in fact n cubed is enough but +this is a hardness proof all we need is + + align:start position:0% +this is a hardness proof all we need is + + + align:start position:0% +this is a hardness proof all we need is +strong hardness we just need n cubed + + align:start position:0% +strong hardness we just need n cubed + + + align:start position:0% +strong hardness we just need n cubed +that's just fine or n to the fifth any + + align:start position:0% +that's just fine or n to the fifth any + + + align:start position:0% +that's just fine or n to the fifth any +polinomial would be + + align:start position:0% +polinomial would be + + + align:start position:0% +polinomial would be +okay so that's a sketch of the reverse + + align:start position:0% +okay so that's a sketch of the reverse + + + align:start position:0% +okay so that's a sketch of the reverse +direction for this proof there are some + + align:start position:0% +direction for this proof there are some + + + align:start position:0% +direction for this proof there are some +more details to make sure everything + + align:start position:0% +more details to make sure everything + + + align:start position:0% +more details to make sure everything +adds up right mod 128 and that you can + + align:start position:0% +adds up right mod 128 and that you can + + + align:start position:0% +adds up right mod 128 and that you can +make all the AIS different and so on but + + align:start position:0% +make all the AIS different and so on but + + + align:start position:0% +make all the AIS different and so on but +the hard part is the vi seems + + align:start position:0% +the hard part is the vi seems + + + align:start position:0% +the hard part is the vi seems +believable questions about Cryptor + + align:start position:0% + + + + align:start position:0% + +rhythms okay + + align:start position:0% +rhythms okay + + + align:start position:0% +rhythms okay +uh cool next uh is an origami proof so + + align:start position:0% +uh cool next uh is an origami proof so + + + align:start position:0% +uh cool next uh is an origami proof so +uh here's sort of the motivating problem + + align:start position:0% +uh here's sort of the motivating problem + + + align:start position:0% +uh here's sort of the motivating problem +I give you some crease pattern which is + + align:start position:0% +I give you some crease pattern which is + + + align:start position:0% +I give you some crease pattern which is +just a graph drawn in the plane no + + align:start position:0% +just a graph drawn in the plane no + + + align:start position:0% +just a graph drawn in the plane no +Crossings and all the edges are straight + + align:start position:0% +Crossings and all the edges are straight + + + align:start position:0% +Crossings and all the edges are straight +segments and you want to fold it into a + + align:start position:0% +segments and you want to fold it into a + + + align:start position:0% +segments and you want to fold it into a +flat + + align:start position:0% +flat + + + align:start position:0% +flat +origami or flat folded state would be + + align:start position:0% +origami or flat folded state would be + + + align:start position:0% +origami or flat folded state would be +the more technical term so this is an + + align:start position:0% +the more technical term so this is an + + + align:start position:0% +the more technical term so this is an +example of what's called an origami + + align:start position:0% +example of what's called an origami + + + align:start position:0% +example of what's called an origami +tessellation but in general what you're + + align:start position:0% +tessellation but in general what you're + + + align:start position:0% +tessellation but in general what you're +allowed to do uh the red lines here mean + + align:start position:0% +allowed to do uh the red lines here mean + + + align:start position:0% +allowed to do uh the red lines here mean +that you fold as a mountain by 180 uh + + align:start position:0% +that you fold as a mountain by 180 uh + + + align:start position:0% +that you fold as a mountain by 180 uh +180° and the blue lines mean you fold a + + align:start position:0% +180° and the blue lines mean you fold a + + + align:start position:0% +180° and the blue lines mean you fold a +valley 180° so they're specifying the + + align:start position:0% +valley 180° so they're specifying the + + + align:start position:0% +valley 180° so they're specifying the +relative orientation but in flat folding + + align:start position:0% +relative orientation but in flat folding + + + align:start position:0% +relative orientation but in flat folding +you're only allowed to go plus or minus + + align:start position:0% +you're only allowed to go plus or minus + + + align:start position:0% +you're only allowed to go plus or minus +180 and then it has to exist now the + + align:start position:0% +180 and then it has to exist now the + + + align:start position:0% +180 and then it has to exist now the +rules for paper are twofold one is that + + align:start position:0% +rules for paper are twofold one is that + + + align:start position:0% +rules for paper are twofold one is that +it doesn't stretch it's an isometric + + align:start position:0% +it doesn't stretch it's an isometric + + + align:start position:0% +it doesn't stretch it's an isometric +mapping of the piece of paper each of + + align:start position:0% +mapping of the piece of paper each of + + + align:start position:0% +mapping of the piece of paper each of +these little polygons is just uh rotated + + align:start position:0% +these little polygons is just uh rotated + + + align:start position:0% +these little polygons is just uh rotated +translated reflected possibly over here + + align:start position:0% +translated reflected possibly over here + + + align:start position:0% +translated reflected possibly over here +they fit together so you don't tear the + + align:start position:0% +they fit together so you don't tear the + + + align:start position:0% +they fit together so you don't tear the +paper they fit together at all the + + align:start position:0% +paper they fit together at all the + + + align:start position:0% +paper they fit together at all the +creases um and there are no Crossings + + align:start position:0% +creases um and there are no Crossings + + + align:start position:0% +creases um and there are no Crossings +because paper can't intersect itself so + + align:start position:0% +because paper can't intersect itself so + + + align:start position:0% +because paper can't intersect itself so +um the geometry is basically determined + + align:start position:0% +um the geometry is basically determined + + + align:start position:0% +um the geometry is basically determined +if you if you say okay I'm going to view + + align:start position:0% +if you if you say okay I'm going to view + + + align:start position:0% +if you if you say okay I'm going to view +this panel as being fixed it doesn't + + align:start position:0% +this panel as being fixed it doesn't + + + align:start position:0% +this panel as being fixed it doesn't +move then this one is going to be a + + align:start position:0% +move then this one is going to be a + + + align:start position:0% +move then this one is going to be a +reflection through this line flipped + + align:start position:0% +reflection through this line flipped + + + align:start position:0% +reflection through this line flipped +over and in general all of these other + + align:start position:0% +over and in general all of these other + + + align:start position:0% +over and in general all of these other +polygons just have to be Reflections + + align:start position:0% +polygons just have to be Reflections + + + align:start position:0% +polygons just have to be Reflections +because every time you fold on a line + + align:start position:0% +because every time you fold on a line + + + align:start position:0% +because every time you fold on a line +and the rules of the game here is you + + align:start position:0% +and the rules of the game here is you + + + align:start position:0% +and the rules of the game here is you +have to fold everywhere there is a + + align:start position:0% +have to fold everywhere there is a + + + align:start position:0% +have to fold everywhere there is a +crease um you can figure out this + + align:start position:0% +crease um you can figure out this + + + align:start position:0% +crease um you can figure out this +polygon will end up here uh relative to + + align:start position:0% +polygon will end up here uh relative to + + + align:start position:0% +polygon will end up here uh relative to +some original polygon so you can figure + + align:start position:0% +some original polygon so you can figure + + + align:start position:0% +some original polygon so you can figure +out pretty much what this looks like as + + align:start position:0% +out pretty much what this looks like as + + + align:start position:0% +out pretty much what this looks like as +an x-ray diagram and the hard part + + align:start position:0% +an x-ray diagram and the hard part + + + align:start position:0% +an x-ray diagram and the hard part +becomes how are how are layers stacked + + align:start position:0% +becomes how are how are layers stacked + + + align:start position:0% +becomes how are how are layers stacked +is this one on top of this one or is + + align:start position:0% +is this one on top of this one or is + + + align:start position:0% +is this one on top of this one or is +this one on top of that one + + align:start position:0% +this one on top of that one + + + align:start position:0% +this one on top of that one +that's why the problem is empty complete + + align:start position:0% +that's why the problem is empty complete + + + align:start position:0% +that's why the problem is empty complete +is that last step deciding which layers + + align:start position:0% +is that last step deciding which layers + + + align:start position:0% +is that last step deciding which layers +are on top of the other in general + + align:start position:0% +are on top of the other in general + + + align:start position:0% +are on top of the other in general +Whenever two layers of paper partially + + align:start position:0% +Whenever two layers of paper partially + + + align:start position:0% +Whenever two layers of paper partially +overlap you have to decide which is on + + align:start position:0% +overlap you have to decide which is on + + + align:start position:0% +overlap you have to decide which is on +top of the other and then there's some + + align:start position:0% +top of the other and then there's some + + + align:start position:0% +top of the other and then there's some +obvious constraints like um get my hands + + align:start position:0% +obvious constraints like um get my hands + + + align:start position:0% +obvious constraints like um get my hands +oriented this is okay but this is not + + align:start position:0% +oriented this is okay but this is not + + + align:start position:0% +oriented this is okay but this is not +okay right if there's one crease of + + align:start position:0% +okay right if there's one crease of + + + align:start position:0% +okay right if there's one crease of +paper here and another crease of paper + + align:start position:0% +paper here and another crease of paper + + + align:start position:0% +paper here and another crease of paper +here then these locally intersect so + + align:start position:0% +here then these locally intersect so + + + align:start position:0% +here then these locally intersect so +this is okay this is okay this is not + + align:start position:0% +this is okay this is okay this is not + + + align:start position:0% +this is okay this is okay this is not +okay that's the rules uh we don't need + + align:start position:0% +okay that's the rules uh we don't need + + + align:start position:0% +okay that's the rules uh we don't need +to know those rules super precisely to + + align:start position:0% +to know those rules super precisely to + + + align:start position:0% +to know those rules super precisely to +understand this proof fairly intuitively + + align:start position:0% +understand this proof fairly intuitively + + + align:start position:0% +understand this proof fairly intuitively +because everything's going to be small + + align:start position:0% +because everything's going to be small + + + align:start position:0% +because everything's going to be small +and quite local uh the basic idea is the + + align:start position:0% +and quite local uh the basic idea is the + + + align:start position:0% +and quite local uh the basic idea is the +following you take um a piece of + + align:start position:0% +following you take um a piece of + + + align:start position:0% +following you take um a piece of +paper and you fold it along two parallel + + align:start position:0% +paper and you fold it along two parallel + + + align:start position:0% +paper and you fold it along two parallel +lines so fold along this line and then + + align:start position:0% +lines so fold along this line and then + + + align:start position:0% +lines so fold along this line and then +along this + + align:start position:0% +along this + + + align:start position:0% +along this +line okay and this is called a pleat and + + align:start position:0% +line okay and this is called a pleat and + + + align:start position:0% +line okay and this is called a pleat and +there are two ways to do it you could do + + align:start position:0% +there are two ways to do it you could do + + + align:start position:0% +there are two ways to do it you could do +one mountain one Valley or you could do + + align:start position:0% +one mountain one Valley or you could do + + + align:start position:0% +one mountain one Valley or you could do +the other one mountain and the other one + + align:start position:0% +the other one mountain and the other one + + + align:start position:0% +the other one mountain and the other one +Valley you can't make them both + + align:start position:0% +Valley you can't make them both + + + align:start position:0% +Valley you can't make them both +mountains because then you'd locally + + align:start position:0% +mountains because then you'd locally + + + align:start position:0% +mountains because then you'd locally +intersect + + align:start position:0% +intersect + + + align:start position:0% +intersect +yourself okay so it could be this way or + + align:start position:0% +yourself okay so it could be this way or + + + align:start position:0% +yourself okay so it could be this way or +it could be the other way I just had it + + align:start position:0% +it could be the other way I just had it + + + align:start position:0% +it could be the other way I just had it +uh little + + align:start position:0% +uh little + + + align:start position:0% +uh little +tedious um and so you have to make that + + align:start position:0% +tedious um and so you have to make that + + + align:start position:0% +tedious um and so you have to make that +choice which one is a mountain which one + + align:start position:0% +choice which one is a mountain which one + + + align:start position:0% +choice which one is a mountain which one +is a + + align:start position:0% +is a + + + align:start position:0% +is a +valley uh that's going to be our truth + + align:start position:0% +valley uh that's going to be our truth + + + align:start position:0% +valley uh that's going to be our truth +signal one we're going to consider one + + align:start position:0% +signal one we're going to consider one + + + align:start position:0% +signal one we're going to consider one +option true the other option false + + align:start position:0% +option true the other option false + + + align:start position:0% +option true the other option false +and as a point of notation we're going + + align:start position:0% +and as a point of notation we're going + + + align:start position:0% +and as a point of notation we're going +to have an arrow in every one of these + + align:start position:0% +to have an arrow in every one of these + + + align:start position:0% +to have an arrow in every one of these +uh we call them wire gadgets and general + + align:start position:0% +uh we call them wire gadgets and general + + + align:start position:0% +uh we call them wire gadgets and general +wires are how we have truth segments + + align:start position:0% +wires are how we have truth segments + + + align:start position:0% +wires are how we have truth segments +truth settings um and so relative to the + + align:start position:0% +truth settings um and so relative to the + + + align:start position:0% +truth settings um and so relative to the +orientation of this Arrow if it's Valley + + align:start position:0% +orientation of this Arrow if it's Valley + + + align:start position:0% +orientation of this Arrow if it's Valley +on the left blue is Valley uh because I + + align:start position:0% +on the left blue is Valley uh because I + + + align:start position:0% +on the left blue is Valley uh because I +guess rivers are in valleys then we'll + + align:start position:0% +guess rivers are in valleys then we'll + + + align:start position:0% +guess rivers are in valleys then we'll +consider it true if there's blue on the + + align:start position:0% +consider it true if there's blue on the + + + align:start position:0% +consider it true if there's blue on the +right we'll consider it false question + + align:start position:0% +right we'll consider it false question + + + align:start position:0% +right we'll consider it false question +just a question about the setup like + + align:start position:0% +just a question about the setup like + + + align:start position:0% +just a question about the setup like +once you draw all the red and blue lines + + align:start position:0% +once you draw all the red and blue lines + + + align:start position:0% +once you draw all the red and blue lines +if there's just one unique answer uh no + + align:start position:0% +if there's just one unique answer uh no + + + align:start position:0% +if there's just one unique answer uh no +the answer is not necessarily unique but + + align:start position:0% +the answer is not necessarily unique but + + + align:start position:0% +the answer is not necessarily unique but +there will be a unique yes or no answer + + align:start position:0% +there will be a unique yes or no answer + + + align:start position:0% +there will be a unique yes or no answer +either it will be flat foldable or not + + align:start position:0% +either it will be flat foldable or not + + + align:start position:0% +either it will be flat foldable or not +but there actually may be many flat + + align:start position:0% +but there actually may be many flat + + + align:start position:0% +but there actually may be many flat +foldings consistent with a given + + align:start position:0% +foldings consistent with a given + + + align:start position:0% +foldings consistent with a given +Mountain Valley assignment in general so + + align:start position:0% +Mountain Valley assignment in general so + + + align:start position:0% +Mountain Valley assignment in general so +we're not worrying about that too much + + align:start position:0% +we're not worrying about that too much + + + align:start position:0% +we're not worrying about that too much +here um we're just worrying about + + align:start position:0% +here um we're just worrying about + + + align:start position:0% +here um we're just worrying about +whether it is feasible whether there's + + align:start position:0% +whether it is feasible whether there's + + + align:start position:0% +whether it is feasible whether there's +some ordering that makes things work + + align:start position:0% +some ordering that makes things work + + + align:start position:0% +some ordering that makes things work +out okay so the idea is this could be + + align:start position:0% +out okay so the idea is this could be + + + align:start position:0% +out okay so the idea is this could be +your variable + + align:start position:0% +your variable + + + align:start position:0% +your variable +some reductions have variable gadgets + + align:start position:0% +some reductions have variable gadgets + + + align:start position:0% +some reductions have variable gadgets +some don't this one is just going to + + align:start position:0% +some don't this one is just going to + + + align:start position:0% +some don't this one is just going to +have a wire the idea is if you say well + + align:start position:0% +have a wire the idea is if you say well + + + align:start position:0% +have a wire the idea is if you say well +there's a plead over here in the paper + + align:start position:0% +there's a plead over here in the paper + + + align:start position:0% +there's a plead over here in the paper +then it could be pleaded one way or the + + align:start position:0% +then it could be pleaded one way or the + + + align:start position:0% +then it could be pleaded one way or the +other and um that serves as a variable + + align:start position:0% +other and um that serves as a variable + + + align:start position:0% +other and um that serves as a variable +that you choose make one choice the + + align:start position:0% +that you choose make one choice the + + + align:start position:0% +that you choose make one choice the +other what we'd like is to make take + + align:start position:0% +other what we'd like is to make take + + + align:start position:0% +other what we'd like is to make take +that truth value and duplicate it make + + align:start position:0% +that truth value and duplicate it make + + + align:start position:0% +that truth value and duplicate it make +many copies but that's not the next + + align:start position:0% +many copies but that's not the next + + + align:start position:0% +many copies but that's not the next +Gadget the next Gadget is a not all + + align:start position:0% +Gadget the next Gadget is a not all + + + align:start position:0% +Gadget the next Gadget is a not all +equal Clause Gadget so this is going to + + align:start position:0% +equal Clause Gadget so this is going to + + + align:start position:0% +equal Clause Gadget so this is going to +be a reduction from not all equal three + + align:start position:0% +be a reduction from not all equal three + + + align:start position:0% +be a reduction from not all equal three +set and I have the gadget pre-old fold + + align:start position:0% +set and I have the gadget pre-old fold + + + align:start position:0% +set and I have the gadget pre-old fold +it here um so this is uh what in origami + + align:start position:0% +it here um so this is uh what in origami + + + align:start position:0% +it here um so this is uh what in origami +world is called a triangular twist it's + + align:start position:0% +world is called a triangular twist it's + + + align:start position:0% +world is called a triangular twist it's +a slightly weird triangular twist in + + align:start position:0% +a slightly weird triangular twist in + + + align:start position:0% +a slightly weird triangular twist in +that this is 35° instead + + align:start position:0% +that this is 35° instead + + + align:start position:0% +that this is 35° instead +of 30 be the usual one uh and that is so + + align:start position:0% +of 30 be the usual one uh and that is so + + + align:start position:0% +of 30 be the usual one uh and that is so +it's just a little bit larger and that + + align:start position:0% +it's just a little bit larger and that + + + align:start position:0% +it's just a little bit larger and that +causes a problem so this is an example + + align:start position:0% +causes a problem so this is an example + + + align:start position:0% +causes a problem so this is an example +of a valid flat folding of that Gadget + + align:start position:0% +of a valid flat folding of that Gadget + + + align:start position:0% +of a valid flat folding of that Gadget +and if you look at the three ple the + + align:start position:0% +and if you look at the three ple the + + + align:start position:0% +and if you look at the three ple the +three pleats that are coming in notice + + align:start position:0% +three pleats that are coming in notice + + + align:start position:0% +three pleats that are coming in notice +the arrows are all pointing in so it's + + align:start position:0% +the arrows are all pointing in so it's + + + align:start position:0% +the arrows are all pointing in so it's +sort of symmetric uh it's going to be + + align:start position:0% +sort of symmetric uh it's going to be + + + align:start position:0% +sort of symmetric uh it's going to be +one of the valid ones um so I guess it's + + align:start position:0% +one of the valid ones um so I guess it's + + + align:start position:0% +one of the valid ones um so I guess it's +actually written on the diagram here + + align:start position:0% +actually written on the diagram here + + + align:start position:0% +actually written on the diagram here +this one is considered true uh because + + align:start position:0% +this one is considered true uh because + + + align:start position:0% +this one is considered true uh because +there's a valley on your right this one + + align:start position:0% +there's a valley on your right this one + + + align:start position:0% +there's a valley on your right this one +is + + align:start position:0% +is + + + align:start position:0% +is +considered false because there's a + + align:start position:0% +considered false because there's a + + + align:start position:0% +considered false because there's a +valley on your oh I'm so + + align:start position:0% +valley on your oh I'm so + + + align:start position:0% +valley on your oh I'm so +confused uh on your right yeah and this + + align:start position:0% +confused uh on your right yeah and this + + + align:start position:0% +confused uh on your right yeah and this +one is considered true because there's a + + align:start position:0% +one is considered true because there's a + + + align:start position:0% +one is considered true because there's a +valley on your left sorry false cuz + + align:start position:0% +valley on your left sorry false cuz + + + align:start position:0% +valley on your left sorry false cuz +because there's a valley on your right + + align:start position:0% +because there's a valley on your right + + + align:start position:0% +because there's a valley on your right +if you're walking down the arrow then + + align:start position:0% +if you're walking down the arrow then + + + align:start position:0% +if you're walking down the arrow then +the right hand side has a valley uh and + + align:start position:0% +the right hand side has a valley uh and + + + align:start position:0% +the right hand side has a valley uh and +so this happens to fold because they're + + align:start position:0% +so this happens to fold because they're + + + align:start position:0% +so this happens to fold because they're +not all the same if you tried to make + + align:start position:0% +not all the same if you tried to make + + + align:start position:0% +not all the same if you tried to make +them all the same which would be like + + align:start position:0% +them all the same which would be like + + + align:start position:0% +them all the same which would be like +reversing the + + align:start position:0% +reversing the + + + align:start position:0% +reversing the +true uh it's going to look something + + align:start position:0% +true uh it's going to look something + + + align:start position:0% +true uh it's going to look something +like + + align:start position:0% + + + + align:start position:0% + +this okay which it's actually easier to + + align:start position:0% +this okay which it's actually easier to + + + align:start position:0% +this okay which it's actually easier to +see back here so now they're all trying + + align:start position:0% +see back here so now they're all trying + + + align:start position:0% +see back here so now they're all trying +to fold the same way uh but the problem + + align:start position:0% +to fold the same way uh but the problem + + + align:start position:0% +to fold the same way uh but the problem +is on this side sorry these guys will + + align:start position:0% +is on this side sorry these guys will + + + align:start position:0% +is on this side sorry these guys will +all come and intersect in the center and + + align:start position:0% +all come and intersect in the center and + + + align:start position:0% +all come and intersect in the center and +it's uh I think we have a diagram here + + align:start position:0% +it's uh I think we have a diagram here + + + align:start position:0% +it's uh I think we have a diagram here +and sort of in x-ray this is what must + + align:start position:0% +and sort of in x-ray this is what must + + + align:start position:0% +and sort of in x-ray this is what must +happen and there's this little area of + + align:start position:0% +happen and there's this little area of + + + align:start position:0% +happen and there's this little area of +intersection where you cannot resolve + + align:start position:0% +intersection where you cannot resolve + + + align:start position:0% +intersection where you cannot resolve +which of these three things are on top + + align:start position:0% +which of these three things are on top + + + align:start position:0% +which of these three things are on top +of each other because this one wants to + + align:start position:0% +of each other because this one wants to + + + align:start position:0% +of each other because this one wants to +be on top of this one wants to be on top + + align:start position:0% +be on top of this one wants to be on top + + + align:start position:0% +be on top of this one wants to be on top +of this one wants to be on top of this + + align:start position:0% +of this one wants to be on top of this + + + align:start position:0% +of this one wants to be on top of this +one so there's a cycle of constraints no + + align:start position:0% +one so there's a cycle of constraints no + + + align:start position:0% +one so there's a cycle of constraints no +one can be on top of each other at in + + align:start position:0% +one can be on top of each other at in + + + align:start position:0% +one can be on top of each other at in +this little region in the regular + + align:start position:0% +this little region in the regular + + + align:start position:0% +this little region in the regular +triangle twist this is a point and + + align:start position:0% +triangle twist this is a point and + + + align:start position:0% +triangle twist this is a point and +everything's fine but but the way these + + align:start position:0% +everything's fine but but the way these + + + align:start position:0% +everything's fine but but the way these +angles are set up there's this area of + + align:start position:0% +angles are set up there's this area of + + + align:start position:0% +angles are set up there's this area of +overlap and in that one situation you're + + align:start position:0% +overlap and in that one situation you're + + + align:start position:0% +overlap and in that one situation you're +toast so if they're all true but of + + align:start position:0% +toast so if they're all true but of + + + align:start position:0% +toast so if they're all true but of +course everything's symmetric if you + + align:start position:0% +course everything's symmetric if you + + + align:start position:0% +course everything's symmetric if you +flip it over then it's the same if + + align:start position:0% +flip it over then it's the same if + + + align:start position:0% +flip it over then it's the same if +they're all false so you forbid all true + + align:start position:0% +they're all false so you forbid all true + + + align:start position:0% +they're all false so you forbid all true +you forbid all false everything else + + align:start position:0% +you forbid all false everything else + + + align:start position:0% +you forbid all false everything else +will work so this is not all equal this + + align:start position:0% +will work so this is not all equal this + + + align:start position:0% +will work so this is not all equal this +will be flat foldable locally if and + + align:start position:0% +will be flat foldable locally if and + + + align:start position:0% +will be flat foldable locally if and +only if uh those those variable + + align:start position:0% +only if uh those those variable + + + align:start position:0% +only if uh those those variable +assignments are not all + + align:start position:0% +assignments are not all + + + align:start position:0% +assignments are not all +equal okay now uh we need a couple more + + align:start position:0% +equal okay now uh we need a couple more + + + align:start position:0% +equal okay now uh we need a couple more +gadgets for this to work one is the + + align:start position:0% +gadgets for this to work one is the + + + align:start position:0% +gadgets for this to work one is the +ability to duplicate a signal and the + + align:start position:0% +ability to duplicate a signal and the + + + align:start position:0% +ability to duplicate a signal and the +other is a + + align:start position:0% +other is a + + + align:start position:0% +other is a +crossover so here is uh this is a proof + + align:start position:0% +crossover so here is uh this is a proof + + + align:start position:0% +crossover so here is uh this is a proof +by burn and hay by the way this is I + + align:start position:0% +by burn and hay by the way this is I + + + align:start position:0% +by burn and hay by the way this is I +think the first or second paper in + + align:start position:0% +think the first or second paper in + + + align:start position:0% +think the first or second paper in +computational origami so got things off + + align:start position:0% +computational origami so got things off + + + align:start position:0% +computational origami so got things off +to an exciting start uh this is a uh + + align:start position:0% +to an exciting start uh this is a uh + + + align:start position:0% +to an exciting start uh this is a uh +splitter negation Gadget uh this is what + + align:start position:0% +splitter negation Gadget uh this is what + + + align:start position:0% +splitter negation Gadget uh this is what +it folds like it looks a little bit + + align:start position:0% +it folds like it looks a little bit + + + align:start position:0% +it folds like it looks a little bit +weird uh cuz my paper is a little bit + + align:start position:0% +weird uh cuz my paper is a little bit + + + align:start position:0% +weird uh cuz my paper is a little bit +small but uh the point is there's + + align:start position:0% +small but uh the point is there's + + + align:start position:0% +small but uh the point is there's +essentially only one way to fold this + + align:start position:0% +essentially only one way to fold this + + + align:start position:0% +essentially only one way to fold this +and if you take 6849 you'll know this + + align:start position:0% +and if you take 6849 you'll know this + + + align:start position:0% +and if you take 6849 you'll know this +little local analysis that forces + + align:start position:0% +little local analysis that forces + + + align:start position:0% +little local analysis that forces +different mountains and valleys to be + + align:start position:0% +different mountains and valleys to be + + + align:start position:0% +different mountains and valleys to be +the same for example these two have to + + align:start position:0% +the same for example these two have to + + + align:start position:0% +the same for example these two have to +be opposite which forces if this is a + + align:start position:0% +be opposite which forces if this is a + + + align:start position:0% +be opposite which forces if this is a +true this one must be a false uh so + + align:start position:0% +true this one must be a false uh so + + + align:start position:0% +true this one must be a false uh so +that's your negation and also uh from a + + align:start position:0% +that's your negation and also uh from a + + + align:start position:0% +that's your negation and also uh from a +local analysis of this vertex if this + + align:start position:0% +local analysis of this vertex if this + + + align:start position:0% +local analysis of this vertex if this +one is true this one must be + + align:start position:0% +one is true this one must be + + + align:start position:0% +one is true this one must be +true and it works and it also works in + + align:start position:0% +true and it works and it also works in + + + align:start position:0% +true and it works and it also works in +the inverse setup that's always going to + + align:start position:0% +the inverse setup that's always going to + + + align:start position:0% +the inverse setup that's always going to +be true uh a natural reason for us to be + + align:start position:0% +be true uh a natural reason for us to be + + + align:start position:0% +be true uh a natural reason for us to be +using not all equal three side here is + + align:start position:0% +using not all equal three side here is + + + align:start position:0% +using not all equal three side here is +there's really no preference between + + align:start position:0% +there's really no preference between + + + align:start position:0% +there's really no preference between +true and false there sort of there not + + align:start position:0% +true and false there sort of there not + + + align:start position:0% +true and false there sort of there not +really a logical notion it's more like + + align:start position:0% +really a logical notion it's more like + + + align:start position:0% +really a logical notion it's more like +red and blue literally red and blue um + + align:start position:0% +red and blue literally red and blue um + + + align:start position:0% +red and blue literally red and blue um +so notal equal is the one that's nice + + align:start position:0% +so notal equal is the one that's nice + + + align:start position:0% +so notal equal is the one that's nice +and symmetric it has no preference + + align:start position:0% +and symmetric it has no preference + + + align:start position:0% +and symmetric it has no preference +between red and blue and so we're seeing + + align:start position:0% +between red and blue and so we're seeing + + + align:start position:0% +between red and blue and so we're seeing +that here because everything's + + align:start position:0% +that here because everything's + + + align:start position:0% +that here because everything's +invertible we want that symmetry between + + align:start position:0% +invertible we want that symmetry between + + + align:start position:0% +invertible we want that symmetry between +red and blue so that would be one reason + + align:start position:0% +red and blue so that would be one reason + + + align:start position:0% +red and blue so that would be one reason +to guess not all equal 3at is a good + + align:start position:0% +to guess not all equal 3at is a good + + + align:start position:0% +to guess not all equal 3at is a good +choice here at least for that wire uh so + + align:start position:0% +choice here at least for that wire uh so + + + align:start position:0% +choice here at least for that wire uh so +cool if we have a signal we can make a + + align:start position:0% +cool if we have a signal we can make a + + + align:start position:0% +cool if we have a signal we can make a +copy we also uh well we sort of get two + + align:start position:0% +copy we also uh well we sort of get two + + + align:start position:0% +copy we also uh well we sort of get two +copies one of them happens to be negated + + align:start position:0% +copies one of them happens to be negated + + + align:start position:0% +copies one of them happens to be negated +with this particular choice of Arrow + + align:start position:0% +with this particular choice of Arrow + + + align:start position:0% +with this particular choice of Arrow +orientation um if we oriented the arrow + + align:start position:0% +orientation um if we oriented the arrow + + + align:start position:0% +orientation um if we oriented the arrow +the other way you could call that a copy + + align:start position:0% +the other way you could call that a copy + + + align:start position:0% +the other way you could call that a copy +but we don't want to take a wire that's + + align:start position:0% +but we don't want to take a wire that's + + + align:start position:0% +but we don't want to take a wire that's +pointing backwards so because we need to + + align:start position:0% +pointing backwards so because we need to + + + align:start position:0% +pointing backwards so because we need to +attach this to something else uh these + + align:start position:0% +attach this to something else uh these + + + align:start position:0% +attach this to something else uh these +all have very particular angles but it + + align:start position:0% +all have very particular angles but it + + + align:start position:0% +all have very particular angles but it +turns out that will be okay one more + + align:start position:0% +turns out that will be okay one more + + + align:start position:0% +turns out that will be okay one more +Gadget is a crossover Gadget this is + + align:start position:0% +Gadget is a crossover Gadget this is + + + align:start position:0% +Gadget is a crossover Gadget this is +very simple it is just one oh this is uh + + align:start position:0% +very simple it is just one oh this is uh + + + align:start position:0% +very simple it is just one oh this is uh +not the pre-folded one you do one pleat + + align:start position:0% +not the pre-folded one you do one pleat + + + align:start position:0% +not the pre-folded one you do one pleat +and then you do the other pleet uh and + + align:start position:0% +and then you do the other pleet uh and + + + align:start position:0% +and then you do the other pleet uh and +you can see from the crease pattern you + + align:start position:0% +you can see from the crease pattern you + + + align:start position:0% +you can see from the crease pattern you +have to do this pleet and then do this + + align:start position:0% +have to do this pleet and then do this + + + align:start position:0% +have to do this pleet and then do this +ple but it's completely independent I + + align:start position:0% +ple but it's completely independent I + + + align:start position:0% +ple but it's completely independent I +could do each ple either way it doesn't + + align:start position:0% +could do each ple either way it doesn't + + + align:start position:0% +could do each ple either way it doesn't +affect the other one so that's crossover + + align:start position:0% +affect the other one so that's crossover + + + align:start position:0% +affect the other one so that's crossover +done easy this works with pretty much + + align:start position:0% +done easy this works with pretty much + + + align:start position:0% +done easy this works with pretty much +any + + align:start position:0% +any + + + align:start position:0% +any +angles uh and then it's just a matter of + + align:start position:0% +angles uh and then it's just a matter of + + + align:start position:0% +angles uh and then it's just a matter of +checking that you can fit all the + + align:start position:0% +checking that you can fit all the + + + align:start position:0% +checking that you can fit all the +gadgets together um this is something we + + align:start position:0% +gadgets together um this is something we + + + align:start position:0% +gadgets together um this is something we +did in our book to get a picture of how + + align:start position:0% +did in our book to get a picture of how + + + align:start position:0% +did in our book to get a picture of how +everything works but in general the idea + + align:start position:0% +everything works but in general the idea + + + align:start position:0% +everything works but in general the idea +is on the left side of the page we have + + align:start position:0% +is on the left side of the page we have + + + align:start position:0% +is on the left side of the page we have +all of our variables those are just + + align:start position:0% +all of our variables those are just + + + align:start position:0% +all of our variables those are just +wires so they can go one way or the + + align:start position:0% +wires so they can go one way or the + + + align:start position:0% +wires so they can go one way or the +other so the idea is uh here is X2 we + + align:start position:0% +other so the idea is uh here is X2 we + + + align:start position:0% +other so the idea is uh here is X2 we +just I just want to bend it so it's + + align:start position:0% +just I just want to bend it so it's + + + align:start position:0% +just I just want to bend it so it's +pointing down Wards so I'm going to use + + align:start position:0% +pointing down Wards so I'm going to use + + + align:start position:0% +pointing down Wards so I'm going to use +the splitter SL negation Gadget so we + + align:start position:0% +the splitter SL negation Gadget so we + + + align:start position:0% +the splitter SL negation Gadget so we +get this copy of X2 just going off it's + + align:start position:0% +get this copy of X2 just going off it's + + + align:start position:0% +get this copy of X2 just going off it's +going to go up to the top of the page no + + align:start position:0% +going to go up to the top of the page no + + + align:start position:0% +going to go up to the top of the page no +big deal just throw it away then we're + + align:start position:0% +big deal just throw it away then we're + + + align:start position:0% +big deal just throw it away then we're +going to go over here something happens + + align:start position:0% +going to go over here something happens + + + align:start position:0% +going to go over here something happens +to cross us but we don't care uh now + + align:start position:0% +to cross us but we don't care uh now + + + align:start position:0% +to cross us but we don't care uh now +what I would like to do looks like this + + align:start position:0% +what I would like to do looks like this + + + align:start position:0% +what I would like to do looks like this +Clause involves X2 so I'm going to do + + align:start position:0% +Clause involves X2 so I'm going to do + + + align:start position:0% +Clause involves X2 so I'm going to do +this funny kind of turnaround + + align:start position:0% +this funny kind of turnaround + + + align:start position:0% +this funny kind of turnaround +thingy uh which will end up making a + + align:start position:0% +thingy uh which will end up making a + + + align:start position:0% +thingy uh which will end up making a +copy of this variable pointing straight + + align:start position:0% +copy of this variable pointing straight + + + align:start position:0% +copy of this variable pointing straight +up and also we'll make a copy of the + + align:start position:0% +up and also we'll make a copy of the + + + align:start position:0% +up and also we'll make a copy of the +variable pointing in this direction and + + align:start position:0% +variable pointing in this direction and + + + align:start position:0% +variable pointing in this direction and +so in general I'm going to keep doing + + align:start position:0% +so in general I'm going to keep doing + + + align:start position:0% +so in general I'm going to keep doing +that uh and whenever I need a copy I'll + + align:start position:0% +that uh and whenever I need a copy I'll + + + align:start position:0% +that uh and whenever I need a copy I'll +just use an appropriate parity of turns + + align:start position:0% +just use an appropriate parity of turns + + + align:start position:0% +just use an appropriate parity of turns +to get a positive copy uh so this is + + align:start position:0% +to get a positive copy uh so this is + + + align:start position:0% +to get a positive copy uh so this is +negated uh and then this is a copy of + + align:start position:0% +negated uh and then this is a copy of + + + align:start position:0% +negated uh and then this is a copy of +the negation and then we flip it one two + + align:start position:0% +the negation and then we flip it one two + + + align:start position:0% +the negation and then we flip it one two +three times so in the end it should be + + align:start position:0% +three times so in the end it should be + + + align:start position:0% +three times so in the end it should be +positive this is the tricky part to + + align:start position:0% +positive this is the tricky part to + + + align:start position:0% +positive this is the tricky part to +check here we have uh a not all equal + + align:start position:0% +check here we have uh a not all equal + + + align:start position:0% +check here we have uh a not all equal +threat Clause where three things come + + align:start position:0% +threat Clause where three things come + + + align:start position:0% +threat Clause where three things come +together and that's going to be foldable + + align:start position:0% +together and that's going to be foldable + + + align:start position:0% +together and that's going to be foldable +if and only if the three variables that + + align:start position:0% +if and only if the three variables that + + + align:start position:0% +if and only if the three variables that +that we're combining have a reasonable + + align:start position:0% +that we're combining have a reasonable + + + align:start position:0% +that we're combining have a reasonable +assignment and then we just have to copy + + align:start position:0% +assignment and then we just have to copy + + + align:start position:0% +assignment and then we just have to copy +all these things and get them to meet + + align:start position:0% +all these things and get them to meet + + + align:start position:0% +all these things and get them to meet +all at the those nexuses at the top so + + align:start position:0% +all at the those nexuses at the top so + + + align:start position:0% +all at the those nexuses at the top so +definitely tricky to make sure this + + align:start position:0% +definitely tricky to make sure this + + + align:start position:0% +definitely tricky to make sure this +works to guarantee all of the + + align:start position:0% +works to guarantee all of the + + + align:start position:0% +works to guarantee all of the +coordinates can be encoded with a + + align:start position:0% +coordinates can be encoded with a + + + align:start position:0% +coordinates can be encoded with a +polinomial number of bits and therefore + + align:start position:0% +polinomial number of bits and therefore + + + align:start position:0% +polinomial number of bits and therefore +this is a strongly NP hard proof but I'm + + align:start position:0% +this is a strongly NP hard proof but I'm + + + align:start position:0% +this is a strongly NP hard proof but I'm +going to wave my hands at those + + align:start position:0% + + + + align:start position:0% + +details + + align:start position:0% +details + + + align:start position:0% +details +questions the if it's any constellation + + align:start position:0% +questions the if it's any constellation + + + align:start position:0% +questions the if it's any constellation +the original proof also alwayss it + + align:start position:0% +the original proof also alwayss it + + + align:start position:0% +the original proof also alwayss it +handed these details but if you have a + + align:start position:0% +handed these details but if you have a + + + align:start position:0% +handed these details but if you have a +fold pattern like this can you tell what + + align:start position:0% +fold pattern like this can you tell what + + + align:start position:0% +fold pattern like this can you tell what +order you would need to do the folds in + + align:start position:0% +order you would need to do the folds in + + + align:start position:0% +order you would need to do the folds in +there's no such thing as order of the + + align:start position:0% +there's no such thing as order of the + + + align:start position:0% +there's no such thing as order of the +folds here all of the folds would be + + align:start position:0% +folds here all of the folds would be + + + align:start position:0% +folds here all of the folds would be +folded simultaneously more or less + + align:start position:0% +folded simultaneously more or less + + + align:start position:0% +folded simultaneously more or less +instantaneously instantaneously to make + + align:start position:0% +instantaneously instantaneously to make + + + align:start position:0% +instantaneously instantaneously to make +it even more precise so here was really + + align:start position:0% +it even more precise so here was really + + + align:start position:0% +it even more precise so here was really +a question of whether there is a flat + + align:start position:0% +a question of whether there is a flat + + + align:start position:0% +a question of whether there is a flat +folded State we're not worried about the + + align:start position:0% +folded State we're not worried about the + + + align:start position:0% +folded State we're not worried about the +motion to get there that's another topic + + align:start position:0% +motion to get there that's another topic + + + align:start position:0% +motion to get there that's another topic +which you should take a49 if you're + + align:start position:0% +which you should take a49 if you're + + + align:start position:0% +which you should take a49 if you're +curious about um but these kinds of + + align:start position:0% +curious about um but these kinds of + + + align:start position:0% +curious about um but these kinds of +patterns there you can't do one thing + + align:start position:0% +patterns there you can't do one thing + + + align:start position:0% +patterns there you can't do one thing +because there's no pleat that goes all + + align:start position:0% +because there's no pleat that goes all + + + align:start position:0% +because there's no pleat that goes all +the way so that's life unlike the + + align:start position:0% +the way so that's life unlike the + + + align:start position:0% +the way so that's life unlike the +folding problem we saw two classes ago + + align:start position:0% +folding problem we saw two classes ago + + + align:start position:0% +folding problem we saw two classes ago +the map folding where we're were doing + + align:start position:0% +the map folding where we're were doing + + + align:start position:0% +the map folding where we're were doing +one then the other there in the notion + + align:start position:0% +one then the other there in the notion + + + align:start position:0% +one then the other there in the notion +of simple folds there's an ordering but + + align:start position:0% +of simple folds there's an ordering but + + + align:start position:0% +of simple folds there's an ordering but +in general origami there is no + + align:start position:0% +in general origami there is no + + + align:start position:0% +in general origami there is no +ordering + + align:start position:0% +ordering + + + align:start position:0% +ordering +cool good that is origami stuff um the + + align:start position:0% +cool good that is origami stuff um the + + + align:start position:0% +cool good that is origami stuff um the +next topic is a more kind of graph + + align:start position:0% +next topic is a more kind of graph + + + align:start position:0% +next topic is a more kind of graph +theoretic basic question uh but it will + + align:start position:0% +theoretic basic question uh but it will + + + align:start position:0% +theoretic basic question uh but it will +also relate to a puzzle um and this the + + align:start position:0% +also relate to a puzzle um and this the + + + align:start position:0% +also relate to a puzzle um and this the +idea of vertex disjoint paths this is in + + align:start position:0% +idea of vertex disjoint paths this is in + + + align:start position:0% +idea of vertex disjoint paths this is in +uh Jason Lynch's early work before he + + align:start position:0% +uh Jason Lynch's early work before he + + + align:start position:0% +uh Jason Lynch's early work before he +was + + align:start position:0% +was + + + align:start position:0% +was +born I assume no relation um 1975 uh so + + align:start position:0% +born I assume no relation um 1975 uh so + + + align:start position:0% +born I assume no relation um 1975 uh so +early days of NP completeness uh this + + align:start position:0% +early days of NP completeness uh this + + + align:start position:0% +early days of NP completeness uh this +problem vertex disjoint paths uh in a + + align:start position:0% +problem vertex disjoint paths uh in a + + + align:start position:0% +problem vertex disjoint paths uh in a +graph As proved and be complete so uh + + align:start position:0% +graph As proved and be complete so uh + + + align:start position:0% +graph As proved and be complete so uh +the problem is I give you a bunch of + + align:start position:0% +the problem is I give you a bunch of + + + align:start position:0% +the problem is I give you a bunch of +terminal pairs via V1 V1 Prime V2 V2 + + align:start position:0% +terminal pairs via V1 V1 Prime V2 V2 + + + align:start position:0% +terminal pairs via V1 V1 Prime V2 V2 +Prime and so on C1 C1 prime a bunch ofir + + align:start position:0% +Prime and so on C1 C1 prime a bunch ofir + + + align:start position:0% +Prime and so on C1 C1 prime a bunch ofir +pairs of vertices and I want to connect + + align:start position:0% +pairs of vertices and I want to connect + + + align:start position:0% +pairs of vertices and I want to connect +the pairs by paths so I want to find a + + align:start position:0% +the pairs by paths so I want to find a + + + align:start position:0% +the pairs by paths so I want to find a +path from V1 to V1 Prime and so on so + + align:start position:0% +path from V1 to V1 Prime and so on so + + + align:start position:0% +path from V1 to V1 Prime and so on so +that those paths are all vertex + + align:start position:0% +that those paths are all vertex + + + align:start position:0% +that those paths are all vertex +disjoint here's the hardness proof super + + align:start position:0% +disjoint here's the hardness proof super + + + align:start position:0% +disjoint here's the hardness proof super +simple this is like one of the easiest + + align:start position:0% +simple this is like one of the easiest + + + align:start position:0% +simple this is like one of the easiest +thre Set uh reductions this is not the + + align:start position:0% +thre Set uh reductions this is not the + + + align:start position:0% +thre Set uh reductions this is not the +end of their paper they do more + + align:start position:0% +end of their paper they do more + + + align:start position:0% +end of their paper they do more +interesting things which I will get to + + align:start position:0% +interesting things which I will get to + + + align:start position:0% +interesting things which I will get to +but first let's understand this one so + + align:start position:0% +but first let's understand this one so + + + align:start position:0% +but first let's understand this one so +uh this is a graph and I've drawn it in + + align:start position:0% +uh this is a graph and I've drawn it in + + + align:start position:0% +uh this is a graph and I've drawn it in +a funny way uh these are vertices these + + align:start position:0% +a funny way uh these are vertices these + + + align:start position:0% +a funny way uh these are vertices these +are vertices these are not vertices + + align:start position:0% +are vertices these are not vertices + + + align:start position:0% +are vertices these are not vertices +those are just in the plane they happen + + align:start position:0% +those are just in the plane they happen + + + align:start position:0% +those are just in the plane they happen +to cross but there's no vertex there so + + align:start position:0% +to cross but there's no vertex there so + + + align:start position:0% +to cross but there's no vertex there so +it's just a straight path all the way + + align:start position:0% +it's just a straight path all the way + + + align:start position:0% +it's just a straight path all the way +through um kind of similar to what we + + align:start position:0% +through um kind of similar to what we + + + align:start position:0% +through um kind of similar to what we +did with football the idea is that if + + align:start position:0% +did with football the idea is that if + + + align:start position:0% +did with football the idea is that if +from V1 to V1 Prime there are two paths + + align:start position:0% +from V1 to V1 Prime there are two paths + + + align:start position:0% +from V1 to V1 Prime there are two paths +at least that stay here you could try to + + align:start position:0% +at least that stay here you could try to + + + align:start position:0% +at least that stay here you could try to +go into a clause path and wreck havoc + + align:start position:0% +go into a clause path and wreck havoc + + + align:start position:0% +go into a clause path and wreck havoc +but I think you will be doomed I hope so + + align:start position:0% +but I think you will be doomed I hope so + + + align:start position:0% +but I think you will be doomed I hope so +the idea is V1 uh maybe you choose the + + align:start position:0% +the idea is V1 uh maybe you choose the + + + align:start position:0% +the idea is V1 uh maybe you choose the +blue path that will prevent C3 from + + align:start position:0% +blue path that will prevent C3 from + + + align:start position:0% +blue path that will prevent C3 from +using that path because there's an + + align:start position:0% +using that path because there's an + + + align:start position:0% +using that path because there's an +intersection here it won't prevent + + align:start position:0% +intersection here it won't prevent + + + align:start position:0% +intersection here it won't prevent +anybody else because there's no other + + align:start position:0% +anybody else because there's no other + + + align:start position:0% +anybody else because there's no other +vertices here so I use the blue path C3 + + align:start position:0% +vertices here so I use the blue path C3 + + + align:start position:0% +vertices here so I use the blue path C3 +cannot use that path if I use the red + + align:start position:0% +cannot use that path if I use the red + + + align:start position:0% +cannot use that path if I use the red +path C1 can't use this one C2 can't use + + align:start position:0% +path C1 can't use this one C2 can't use + + + align:start position:0% +path C1 can't use this one C2 can't use +this one so again we are blocking the + + align:start position:0% +this one so again we are blocking the + + + align:start position:0% +this one so again we are blocking the +thing that it would be setting false so + + align:start position:0% +thing that it would be setting false so + + + align:start position:0% +thing that it would be setting false so +that means uh let's say red I forget in + + align:start position:0% +that means uh let's say red I forget in + + + align:start position:0% +that means uh let's say red I forget in +this picture let's say red is + + align:start position:0% +this picture let's say red is + + + align:start position:0% +this picture let's say red is +true uh then C1 has a V1 bar in it uh C1 + + align:start position:0% +true uh then C1 has a V1 bar in it uh C1 + + + align:start position:0% +true uh then C1 has a V1 bar in it uh C1 +is happy if you choose the blue path but + + align:start position:0% +is happy if you choose the blue path but + + + align:start position:0% +is happy if you choose the blue path but +it's not happy if you choose the red + + align:start position:0% +it's not happy if you choose the red + + + align:start position:0% +it's not happy if you choose the red +path now C1 to C1 Prime only has to be + + align:start position:0% +path now C1 to C1 Prime only has to be + + + align:start position:0% +path now C1 to C1 Prime only has to be +happy uh if one of these three things + + align:start position:0% +happy uh if one of these three things + + + align:start position:0% +happy uh if one of these three things +are happy that's three set at least one + + align:start position:0% +are happy that's three set at least one + + + align:start position:0% +are happy that's three set at least one +of the things should be set correctly + + align:start position:0% +of the things should be set correctly + + + align:start position:0% +of the things should be set correctly +then there is a path from C1 to C1 prime + + align:start position:0% +then there is a path from C1 to C1 prime + + + align:start position:0% +then there is a path from C1 to C1 prime +otherwise there'll be vertex + + align:start position:0% +otherwise there'll be vertex + + + align:start position:0% +otherwise there'll be vertex +intersections you won't have vertex + + align:start position:0% +intersections you won't have vertex + + + align:start position:0% +intersections you won't have vertex +distrain paths okay so in a graph done + + align:start position:0% +distrain paths okay so in a graph done + + + align:start position:0% +distrain paths okay so in a graph done +now let's make it a planer graph where + + align:start position:0% +now let's make it a planer graph where + + + align:start position:0% +now let's make it a planer graph where +things get fun so this is the original + + align:start position:0% +things get fun so this is the original + + + align:start position:0% +things get fun so this is the original +Gadget I've stared at it for many hours + + align:start position:0% +Gadget I've stared at it for many hours + + + align:start position:0% +Gadget I've stared at it for many hours +but it's it's actually pretty simple + + align:start position:0% +but it's it's actually pretty simple + + + align:start position:0% +but it's it's actually pretty simple +after you stare at it for enough hours + + align:start position:0% +after you stare at it for enough hours + + + align:start position:0% +after you stare at it for enough hours +let me try to convince you of that uh so + + align:start position:0% +let me try to convince you of that uh so + + + align:start position:0% +let me try to convince you of that uh so +we're going to follow I'm going to + + align:start position:0% +we're going to follow I'm going to + + + align:start position:0% +we're going to follow I'm going to +follow the same kind of outline + + align:start position:0% +follow the same kind of outline + + + align:start position:0% +follow the same kind of outline +here uh but we have to get rid of these + + align:start position:0% +here uh but we have to get rid of these + + + align:start position:0% +here uh but we have to get rid of these +These are fine those are intersections + + align:start position:0% +These are fine those are intersections + + + align:start position:0% +These are fine those are intersections +okay but these crossovers we need to + + align:start position:0% +okay but these crossovers we need to + + + align:start position:0% +okay but these crossovers we need to +build a crossover Gadget so the idea is + + align:start position:0% +build a crossover Gadget so the idea is + + + align:start position:0% +build a crossover Gadget so the idea is +instead of V1 to V1 Prime being a single + + align:start position:0% +instead of V1 to V1 Prime being a single + + + align:start position:0% +instead of V1 to V1 Prime being a single +path that's that's going to be a problem + + align:start position:0% +path that's that's going to be a problem + + + align:start position:0% +path that's that's going to be a problem +instead of that I'm going to have it be + + align:start position:0% +instead of that I'm going to have it be + + + align:start position:0% +instead of that I'm going to have it be +several paths and they are going to be + + align:start position:0% +several paths and they are going to be + + + align:start position:0% +several paths and they are going to be +uh nested + + align:start position:0% + + + + align:start position:0% + +brackets + + align:start position:0% +brackets + + + align:start position:0% +brackets +CH + + align:start position:0% + + + + align:start position:0% + +uh okay this is the kind of um thing + + align:start position:0% +uh okay this is the kind of um thing + + + align:start position:0% +uh okay this is the kind of um thing +we're imagining we have some vertex + + align:start position:0% +we're imagining we have some vertex + + + align:start position:0% +we're imagining we have some vertex +pairs which can connect like + + align:start position:0% +pairs which can connect like + + + align:start position:0% +pairs which can connect like +this and there are two ways to connect + + align:start position:0% +this and there are two ways to connect + + + align:start position:0% +this and there are two ways to connect +them in this in what we'll end up being + + align:start position:0% +them in this in what we'll end up being + + + align:start position:0% +them in this in what we'll end up being +the diagram we could connect + + align:start position:0% +the diagram we could connect + + + align:start position:0% +the diagram we could connect +them uh like + + align:start position:0% + + + + align:start position:0% + +this notice I'm still connecting the + + align:start position:0% +this notice I'm still connecting the + + + align:start position:0% +this notice I'm still connecting the +same pairs if I do it + + align:start position:0% + + + + align:start position:0% + +right and the whites do not intersect + + align:start position:0% +right and the whites do not intersect + + + align:start position:0% +right and the whites do not intersect +each other their vertex is joint the + + align:start position:0% +each other their vertex is joint the + + + align:start position:0% +each other their vertex is joint the +Reds do not intersect each other their + + align:start position:0% +Reds do not intersect each other their + + + align:start position:0% +Reds do not intersect each other their +vertex is joint but if you tried to + + align:start position:0% +vertex is joint but if you tried to + + + align:start position:0% +vertex is joint but if you tried to +switch from right to Red you'd get + + align:start position:0% +switch from right to Red you'd get + + + align:start position:0% +switch from right to Red you'd get +intersections right so with the same + + align:start position:0% +intersections right so with the same + + + align:start position:0% +intersections right so with the same +there's exactly two settings here so + + align:start position:0% +there's exactly two settings here so + + + align:start position:0% +there's exactly two settings here so +this is a wire once I choose over here + + align:start position:0% +this is a wire once I choose over here + + + align:start position:0% +this is a wire once I choose over here +white or red all the others are forced + + align:start position:0% +white or red all the others are forced + + + align:start position:0% +white or red all the others are forced +to + + align:start position:0% +to + + + align:start position:0% +to +alternate uh sorry once I choose up or + + align:start position:0% +alternate uh sorry once I choose up or + + + align:start position:0% +alternate uh sorry once I choose up or +down the rest are forced to alternate up + + align:start position:0% +down the rest are forced to alternate up + + + align:start position:0% +down the rest are forced to alternate up +or down if I choose white here they're + + align:start position:0% +or down if I choose white here they're + + + align:start position:0% +or down if I choose white here they're +all white I choose red they're all red + + align:start position:0% +all white I choose red they're all red + + + align:start position:0% +all white I choose red they're all red +this is independent for each variable so + + align:start position:0% +this is independent for each variable so + + + align:start position:0% +this is independent for each variable so +independent for each wire so that's + + align:start position:0% +independent for each wire so that's + + + align:start position:0% +independent for each wire so that's +what's going on here and if you look + + align:start position:0% +what's going on here and if you look + + + align:start position:0% +what's going on here and if you look +closely at the Bold lines you've got a + + align:start position:0% +closely at the Bold lines you've got a + + + align:start position:0% +closely at the Bold lines you've got a +bracket here from V1 to X1 then you've + + align:start position:0% +bracket here from V1 to X1 then you've + + + align:start position:0% +bracket here from V1 to X1 then you've +got a bracket here from X2 to X3 then a + + align:start position:0% +got a bracket here from X2 to X3 then a + + + align:start position:0% +got a bracket here from X2 to X3 then a +bracket here from X4 but in general + + align:start position:0% +bracket here from X4 but in general + + + align:start position:0% +bracket here from X4 but in general +there would be lots of those + + align:start position:0% +there would be lots of those + + + align:start position:0% +there would be lots of those +brackets going all the way down the the + + align:start position:0% +brackets going all the way down the the + + + align:start position:0% +brackets going all the way down the the +picture and the cool thing about this is + + align:start position:0% +picture and the cool thing about this is + + + align:start position:0% +picture and the cool thing about this is +you get uh the ability to cross over + + align:start position:0% +you get uh the ability to cross over + + + align:start position:0% +you get uh the ability to cross over +because now if I just restrict this + + align:start position:0% +because now if I just restrict this + + + align:start position:0% +because now if I just restrict this +picture it's hard to see if I just + + align:start position:0% +picture it's hard to see if I just + + + align:start position:0% +picture it's hard to see if I just +restrict to the white + + align:start position:0% +restrict to the white + + + align:start position:0% +restrict to the white +part uh you can go from top to bottom + + align:start position:0% +part uh you can go from top to bottom + + + align:start position:0% +part uh you can go from top to bottom +you just need an appropriate kind of + + align:start position:0% +you just need an appropriate kind of + + + align:start position:0% +you just need an appropriate kind of +zigzag that will let you go from up here + + align:start position:0% +zigzag that will let you go from up here + + + align:start position:0% +zigzag that will let you go from up here +to down there without intersections and + + align:start position:0% +to down there without intersections and + + + align:start position:0% +to down there without intersections and +that's what's happening with this line + + align:start position:0% +that's what's happening with this line + + + align:start position:0% +that's what's happening with this line +it's going over around the brackets and + + align:start position:0% +it's going over around the brackets and + + + align:start position:0% +it's going over around the brackets and +down and so the C1 to C1 Prime can + + align:start position:0% +down and so the C1 to C1 Prime can + + + align:start position:0% +down and so the C1 to C1 Prime can +remain a single path it can always get + + align:start position:0% +remain a single path it can always get + + + align:start position:0% +remain a single path it can always get +through uh if you have this gadget then + + align:start position:0% +through uh if you have this gadget then + + + align:start position:0% +through uh if you have this gadget then +you can have an intersection with no + + align:start position:0% +you can have an intersection with no + + + align:start position:0% +you can have an intersection with no +trouble um but V1 is still communicating + + align:start position:0% +trouble um but V1 is still communicating + + + align:start position:0% +trouble um but V1 is still communicating +information down the line of one setting + + align:start position:0% +information down the line of one setting + + + align:start position:0% +information down the line of one setting +or the other zero or + + align:start position:0% +or the other zero or + + + align:start position:0% +or the other zero or +one okay that's there's some details to + + align:start position:0% +one okay that's there's some details to + + + align:start position:0% +one okay that's there's some details to +check there but uh that's the idea okay + + align:start position:0% +check there but uh that's the idea okay + + + align:start position:0% +check there but uh that's the idea okay +and that's the end of the Lynch paper + + align:start position:0% +and that's the end of the Lynch paper + + + align:start position:0% +and that's the end of the Lynch paper +now uh we were looking at this earlier + + align:start position:0% +now uh we were looking at this earlier + + + align:start position:0% +now uh we were looking at this earlier +this year and we can prove an even + + align:start position:0% +this year and we can prove an even + + + align:start position:0% +this year and we can prove an even +stronger result which is what you might + + align:start position:0% +stronger result which is what you might + + + align:start position:0% +stronger result which is what you might +call planer vertex disjoint paths in a + + align:start position:0% +call planer vertex disjoint paths in a + + + align:start position:0% +call planer vertex disjoint paths in a +rectangle uh but it's not so the idea is + + align:start position:0% +rectangle uh but it's not so the idea is + + + align:start position:0% +rectangle uh but it's not so the idea is +you have a rectangle of 1x one squares + + align:start position:0% +you have a rectangle of 1x one squares + + + align:start position:0% +you have a rectangle of 1x one squares +each 1X one square could be a terminal + + align:start position:0% +each 1X one square could be a terminal + + + align:start position:0% +each 1X one square could be a terminal +and a teral pair or it could just be a + + align:start position:0% +and a teral pair or it could just be a + + + align:start position:0% +and a teral pair or it could just be a +blank space that you can R paths through + + align:start position:0% +blank space that you can R paths through + + + align:start position:0% +blank space that you can R paths through +and my + + align:start position:0% +and my + + + align:start position:0% +and my +goal uh is to find vertex D joint paths + + align:start position:0% +goal uh is to find vertex D joint paths + + + align:start position:0% +goal uh is to find vertex D joint paths +connecting all the terminal pairs but + + align:start position:0% +connecting all the terminal pairs but + + + align:start position:0% +connecting all the terminal pairs but +furthermore I want every square of the + + align:start position:0% +furthermore I want every square of the + + + align:start position:0% +furthermore I want every square of the +grid to be occupied by a path so it's + + align:start position:0% +grid to be occupied by a path so it's + + + align:start position:0% +grid to be occupied by a path so it's +sort of it's not quite hamiltonian path + + align:start position:0% +sort of it's not quite hamiltonian path + + + align:start position:0% +sort of it's not quite hamiltonian path +it's like you have a bunch of paths + + align:start position:0% +it's like you have a bunch of paths + + + align:start position:0% +it's like you have a bunch of paths +where uh that collectively fill the + + align:start position:0% +where uh that collectively fill the + + + align:start position:0% +where uh that collectively fill the +entire + + align:start position:0% +entire + + + align:start position:0% +entire +grid why uh it's motivated by a puzzle + + align:start position:0% +grid why uh it's motivated by a puzzle + + + align:start position:0% +grid why uh it's motivated by a puzzle +but it's natural enough this is a more + + align:start position:0% +but it's natural enough this is a more + + + align:start position:0% +but it's natural enough this is a more +specialized version + + align:start position:0% +specialized version + + + align:start position:0% +specialized version +um so this is also EMP hard and we're + + align:start position:0% +um so this is also EMP hard and we're + + + align:start position:0% +um so this is also EMP hard and we're +going to mimic the same proof and this + + align:start position:0% +going to mimic the same proof and this + + + align:start position:0% +going to mimic the same proof and this +for example is a gadget to do say this + + align:start position:0% +for example is a gadget to do say this + + + align:start position:0% +for example is a gadget to do say this +little picture where you have two + + align:start position:0% +little picture where you have two + + + align:start position:0% +little picture where you have two +choices so maybe uh the V1 dot is + + align:start position:0% +choices so maybe uh the V1 dot is + + + align:start position:0% +choices so maybe uh the V1 dot is +actually here and the idea is you could + + align:start position:0% +actually here and the idea is you could + + + align:start position:0% +actually here and the idea is you could +either follow this path or you could + + align:start position:0% +either follow this path or you could + + + align:start position:0% +either follow this path or you could +follow this path and uh what's also + + align:start position:0% +follow this path and uh what's also + + + align:start position:0% +follow this path and uh what's also +drawn here are lots of other terminal + + align:start position:0% +drawn here are lots of other terminal + + + align:start position:0% +drawn here are lots of other terminal +pairs these are what you might call + + align:start position:0% +pairs these are what you might call + + + align:start position:0% +pairs these are what you might call +adjacent terminal pairs what you might + + align:start position:0% +adjacent terminal pairs what you might + + + align:start position:0% +adjacent terminal pairs what you might +also call obstacles because the paths + + align:start position:0% +also call obstacles because the paths + + + align:start position:0% +also call obstacles because the paths +have to be vertex joint no path can go + + align:start position:0% +have to be vertex joint no path can go + + + align:start position:0% +have to be vertex joint no path can go +through a + + align:start position:0% +through a + + + align:start position:0% +through a +terminal any of these dots serve as + + align:start position:0% +terminal any of these dots serve as + + + align:start position:0% +terminal any of these dots serve as +obstacles so we effectively simulate + + align:start position:0% +obstacles so we effectively simulate + + + align:start position:0% +obstacles so we effectively simulate +this blank space that you're not allowed + + align:start position:0% +this blank space that you're not allowed + + + align:start position:0% +this blank space that you're not allowed +to + + align:start position:0% +to + + + align:start position:0% +to +touch okay uh now the fun part is now + + align:start position:0% +touch okay uh now the fun part is now + + + align:start position:0% +touch okay uh now the fun part is now +maybe those terminal pairs are connected + + align:start position:0% +maybe those terminal pairs are connected + + + align:start position:0% +maybe those terminal pairs are connected +by the single edge that joins them and + + align:start position:0% +by the single edge that joins them and + + + align:start position:0% +by the single edge that joins them and +so doesn't get in the way but there are + + align:start position:0% +so doesn't get in the way but there are + + + align:start position:0% +so doesn't get in the way but there are +other possibilities drawn with these + + align:start position:0% +other possibilities drawn with these + + + align:start position:0% +other possibilities drawn with these +blue lines so instead of going here I + + align:start position:0% +blue lines so instead of going here I + + + align:start position:0% +blue lines so instead of going here I +could do this instead of going here I + + align:start position:0% +could do this instead of going here I + + + align:start position:0% +could do this instead of going here I +could do this and this and then if you + + align:start position:0% +could do this and this and then if you + + + align:start position:0% +could do this and this and then if you +look at this pict picture every pixel + + align:start position:0% +look at this pict picture every pixel + + + align:start position:0% +look at this pict picture every pixel +has a path through + + align:start position:0% +has a path through + + + align:start position:0% +has a path through +it in this case and then here's the + + align:start position:0% +it in this case and then here's the + + + align:start position:0% +it in this case and then here's the +other case again and now I'll fill this + + align:start position:0% +other case again and now I'll fill this + + + align:start position:0% +other case again and now I'll fill this +this these two pixels with this pair and + + align:start position:0% +this these two pixels with this pair and + + + align:start position:0% +this these two pixels with this pair and +now every pixel has a path through it + + align:start position:0% +now every pixel has a path through it + + + align:start position:0% +now every pixel has a path through it +that's my goal is to make sure every + + align:start position:0% +that's my goal is to make sure every + + + align:start position:0% +that's my goal is to make sure every +pixel has a path through it so we're + + align:start position:0% +pixel has a path through it so we're + + + align:start position:0% +pixel has a path through it so we're +just trying to preserve all the + + align:start position:0% +just trying to preserve all the + + + align:start position:0% +just trying to preserve all the +solutions we have here but with the + + align:start position:0% +solutions we have here but with the + + + align:start position:0% +solutions we have here but with the +additional constraint that all of the + + align:start position:0% +additional constraint that all of the + + + align:start position:0% +additional constraint that all of the +because we already know this is + + align:start position:0% +because we already know this is + + + align:start position:0% +because we already know this is +simulating uh three sets we already know + + align:start position:0% +simulating uh three sets we already know + + + align:start position:0% +simulating uh three sets we already know +it's hard uh we just now want to have + + align:start position:0% +it's hard uh we just now want to have + + + align:start position:0% +it's hard uh we just now want to have +this extra constraint that every pixel + + align:start position:0% +this extra constraint that every pixel + + + align:start position:0% +this extra constraint that every pixel +has a path through it and that we live + + align:start position:0% +has a path through it and that we live + + + align:start position:0% +has a path through it and that we live +in a + + align:start position:0% +in a + + + align:start position:0% +in a +rectangle so this looks good um as you + + align:start position:0% +rectangle so this looks good um as you + + + align:start position:0% +rectangle so this looks good um as you +might imagine there's a little bit of + + align:start position:0% +might imagine there's a little bit of + + + align:start position:0% +might imagine there's a little bit of +finesse to make these gadgets work uh + + align:start position:0% +finesse to make these gadgets work uh + + + align:start position:0% +finesse to make these gadgets work uh +you notice some of these guys are + + align:start position:0% +you notice some of these guys are + + + align:start position:0% +you notice some of these guys are +oriented horizontally some of them are + + align:start position:0% +oriented horizontally some of them are + + + align:start position:0% +oriented horizontally some of them are +oriented vertically that's to make it + + align:start position:0% +oriented vertically that's to make it + + + align:start position:0% +oriented vertically that's to make it +work uh but this was easy uh what you're + + align:start position:0% +work uh but this was easy uh what you're + + + align:start position:0% +work uh but this was easy uh what you're +about to see is less easy so let's do + + align:start position:0% +about to see is less easy so let's do + + + align:start position:0% +about to see is less easy so let's do +the crossover Gadget because that's like + + align:start position:0% +the crossover Gadget because that's like + + + align:start position:0% +the crossover Gadget because that's like +the heart of everything and when we were + + align:start position:0% +the heart of everything and when we were + + + align:start position:0% +the heart of everything and when we were +starting on this uh I think this is in + + align:start position:0% +starting on this uh I think this is in + + + align:start position:0% +starting on this uh I think this is in +May uh I was very happy when I could + + align:start position:0% +May uh I was very happy when I could + + + align:start position:0% +May uh I was very happy when I could +finally draw this picture uh sorry this + + align:start position:0% +finally draw this picture uh sorry this + + + align:start position:0% +finally draw this picture uh sorry this +is actually the final Gadget which works + + align:start position:0% +is actually the final Gadget which works + + + align:start position:0% +is actually the final Gadget which works +um but you can see the same kind of + + align:start position:0% +um but you can see the same kind of + + + align:start position:0% +um but you can see the same kind of +picture uh we've got a bracket here that + + align:start position:0% +picture uh we've got a bracket here that + + + align:start position:0% +picture uh we've got a bracket here that +corresponds to this bracket here as + + align:start position:0% +corresponds to this bracket here as + + + align:start position:0% +corresponds to this bracket here as +another bracket here I've just sort of + + align:start position:0% +another bracket here I've just sort of + + + align:start position:0% +another bracket here I've just sort of +rounded it to integer coordinates and + + align:start position:0% +rounded it to integer coordinates and + + + align:start position:0% +rounded it to integer coordinates and +made sure that everything else can be + + align:start position:0% +made sure that everything else can be + + + align:start position:0% +made sure that everything else can be +filled in Easy right uh as a to uh in + + align:start position:0% +filled in Easy right uh as a to uh in + + + align:start position:0% +filled in Easy right uh as a to uh in +the sake of Education let me show you + + align:start position:0% +the sake of Education let me show you + + + align:start position:0% +the sake of Education let me show you +all the things that went wrong in this + + align:start position:0% +all the things that went wrong in this + + + align:start position:0% +all the things that went wrong in this +proof and because it was only a few + + align:start position:0% +proof and because it was only a few + + + align:start position:0% +proof and because it was only a few +months ago I mostly remember everything + + align:start position:0% +months ago I mostly remember everything + + + align:start position:0% +months ago I mostly remember everything +that went wrong which was a lot um so + + align:start position:0% +that went wrong which was a lot um so + + + align:start position:0% +that went wrong which was a lot um so +this was an early version of the gadget + + align:start position:0% +this was an early version of the gadget + + + align:start position:0% +this was an early version of the gadget +not actually the first one but it serves + + align:start position:0% +not actually the first one but it serves + + + align:start position:0% +not actually the first one but it serves +its purpose uh so here we have the two + + align:start position:0% +its purpose uh so here we have the two + + + align:start position:0% +its purpose uh so here we have the two +settings corresponding to these two + + align:start position:0% +settings corresponding to these two + + + align:start position:0% +settings corresponding to these two +settings the up and the down setting the + + align:start position:0% +settings the up and the down setting the + + + align:start position:0% +settings the up and the down setting the +true and the false setting we've got + + align:start position:0% +true and the false setting we've got + + + align:start position:0% +true and the false setting we've got +this path coming through in both cases + + align:start position:0% +this path coming through in both cases + + + align:start position:0% +this path coming through in both cases +it takes a slightly different path over + + align:start position:0% +it takes a slightly different path over + + + align:start position:0% +it takes a slightly different path over +here uh but the and the brackets are + + align:start position:0% +here uh but the and the brackets are + + + align:start position:0% +here uh but the and the brackets are +flipped + + align:start position:0% +flipped + + + align:start position:0% +flipped +uh so the first thing I want to point + + align:start position:0% +uh so the first thing I want to point + + + align:start position:0% +uh so the first thing I want to point +out are these circled nodes um the + + align:start position:0% +out are these circled nodes um the + + + align:start position:0% +out are these circled nodes um the +obvious way to draw this picture is with + + align:start position:0% +obvious way to draw this picture is with + + + align:start position:0% +obvious way to draw this picture is with +all of the terminals in the center row + + align:start position:0% +all of the terminals in the center row + + + align:start position:0% +all of the terminals in the center row +that would be reasonable they're not + + align:start position:0% +that would be reasonable they're not + + + align:start position:0% +that would be reasonable they're not +drawn that way here because imagine at + + align:start position:0% +drawn that way here because imagine at + + + align:start position:0% +drawn that way here because imagine at +this point we're down here and we have + + align:start position:0% +this point we're down here and we have + + + align:start position:0% +this point we're down here and we have +this big path over here then there'll be + + align:start position:0% +this big path over here then there'll be + + + align:start position:0% +this big path over here then there'll be +three pixels here which somehow have to + + align:start position:0% +three pixels here which somehow have to + + + align:start position:0% +three pixels here which somehow have to +be filled and that is trouble because + + align:start position:0% +be filled and that is trouble because + + + align:start position:0% +be filled and that is trouble because +three is odd okay so this is what you + + align:start position:0% +three is odd okay so this is what you + + + align:start position:0% +three is odd okay so this is what you +might call issue one the empty space + + align:start position:0% +might call issue one the empty space + + + align:start position:0% +might call issue one the empty space +wherever you have empty space any group + + align:start position:0% +wherever you have empty space any group + + + align:start position:0% +wherever you have empty space any group +should have even area uh because if you + + align:start position:0% +should have even area uh because if you + + + align:start position:0% +should have even area uh because if you +look at two guys that say are adjacent + + align:start position:0% +look at two guys that say are adjacent + + + align:start position:0% +look at two guys that say are adjacent +and you uh replace them with some other + + align:start position:0% +and you uh replace them with some other + + + align:start position:0% +and you uh replace them with some other +path together that forms a polygon and + + align:start position:0% +path together that forms a polygon and + + + align:start position:0% +path together that forms a polygon and +in the Square grid every polygon has + + align:start position:0% +in the Square grid every polygon has + + + align:start position:0% +in the Square grid every polygon has +even + + align:start position:0% +even + + + align:start position:0% +even +area so you will never fill exactly + + align:start position:0% +area so you will never fill exactly + + + align:start position:0% +area so you will never fill exactly +three spaces and so the the major + + align:start position:0% +three spaces and so the the major + + + align:start position:0% +three spaces and so the the major +Revolution which I spent many hours + + align:start position:0% +Revolution which I spent many hours + + + align:start position:0% +Revolution which I spent many hours +figuring out is if I just move these + + align:start position:0% +figuring out is if I just move these + + + align:start position:0% +figuring out is if I just move these +points up one spot everything just works + + align:start position:0% +points up one spot everything just works + + + align:start position:0% +points up one spot everything just works +uh so happy uh so I figure okay proof's + + align:start position:0% +uh so happy uh so I figure okay proof's + + + align:start position:0% +uh so happy uh so I figure okay proof's +done I drew these two figures and uh + + align:start position:0% +done I drew these two figures and uh + + + align:start position:0% +done I drew these two figures and uh +forgot about it then uh a couple months + + align:start position:0% +forgot about it then uh a couple months + + + align:start position:0% +forgot about it then uh a couple months +later we went to write the paper uh and + + align:start position:0% +later we went to write the paper uh and + + + align:start position:0% +later we went to write the paper uh and +then we get to issue two so issue two is + + align:start position:0% +then we get to issue two so issue two is + + + align:start position:0% +then we get to issue two so issue two is +well this was great this this works fine + + align:start position:0% +well this was great this this works fine + + + align:start position:0% +well this was great this this works fine +if + + align:start position:0% +if + + + align:start position:0% +if +um the Clause path is present if the + + align:start position:0% +um the Clause path is present if the + + + align:start position:0% +um the Clause path is present if the +Clause chooses this vertical path this + + align:start position:0% +Clause chooses this vertical path this + + + align:start position:0% +Clause chooses this vertical path this +will fill everything this will F fill + + align:start position:0% +will fill everything this will F fill + + + align:start position:0% +will fill everything this will F fill +everything but what if the Clause path + + align:start position:0% +everything but what if the Clause path + + + align:start position:0% +everything but what if the Clause path +is absent Clause has three choices it + + align:start position:0% +is absent Clause has three choices it + + + align:start position:0% +is absent Clause has three choices it +may not choose this vertical path so + + align:start position:0% +may not choose this vertical path so + + + align:start position:0% +may not choose this vertical path so +then somehow this stuff has to be + + align:start position:0% +then somehow this stuff has to be + + + align:start position:0% +then somehow this stuff has to be +covered using all the extra filler + + align:start position:0% +covered using all the extra filler + + + align:start position:0% +covered using all the extra filler +stuff okay and uh here I couldn't quite + + align:start position:0% +stuff okay and uh here I couldn't quite + + + align:start position:0% +stuff okay and uh here I couldn't quite +figure out how to fill these things like + + align:start position:0% +figure out how to fill these things like + + + align:start position:0% +figure out how to fill these things like +well maybe I should add a couple more + + align:start position:0% +well maybe I should add a couple more + + + align:start position:0% +well maybe I should add a couple more +rows in the middle that didn't seem to + + align:start position:0% +rows in the middle that didn't seem to + + + align:start position:0% +rows in the middle that didn't seem to +help uh I would I thought this one was + + align:start position:0% +help uh I would I thought this one was + + + align:start position:0% +help uh I would I thought this one was +okay it looks fine until I noticed that + + align:start position:0% +okay it looks fine until I noticed that + + + align:start position:0% +okay it looks fine until I noticed that +well either I connect these two dots by + + align:start position:0% +well either I connect these two dots by + + + align:start position:0% +well either I connect these two dots by +a length to path or I connect it by this + + align:start position:0% +a length to path or I connect it by this + + + align:start position:0% +a length to path or I connect it by this +path but in that case this pixel is + + align:start position:0% +path but in that case this pixel is + + + align:start position:0% +path but in that case this pixel is +uncovered by + + align:start position:0% +uncovered by + + + align:start position:0% +uncovered by +paths so uh and this is bad because + + align:start position:0% +paths so uh and this is bad because + + + align:start position:0% +paths so uh and this is bad because +there's exactly one such pixel which + + align:start position:0% +there's exactly one such pixel which + + + align:start position:0% +there's exactly one such pixel which +means I have another parody problem + + align:start position:0% +means I have another parody problem + + + align:start position:0% +means I have another parody problem +again so uh I think what we ended up + + align:start position:0% +again so uh I think what we ended up + + + align:start position:0% +again so uh I think what we ended up +doing um and you know when you're really + + align:start position:0% +doing um and you know when you're really + + + align:start position:0% +doing um and you know when you're really +doing it you don't immediately realize + + align:start position:0% +doing it you don't immediately realize + + + align:start position:0% +doing it you don't immediately realize +it's a parody problem you have to like I + + align:start position:0% +it's a parody problem you have to like I + + + align:start position:0% +it's a parody problem you have to like I +I've tried trying to fix this many many + + align:start position:0% +I've tried trying to fix this many many + + + align:start position:0% +I've tried trying to fix this many many +times and every single time I have like + + align:start position:0% +times and every single time I have like + + + align:start position:0% +times and every single time I have like +one pixel on covered they like H bet + + align:start position:0% +one pixel on covered they like H bet + + + align:start position:0% +one pixel on covered they like H bet +there's a theorem here and then I proved + + align:start position:0% +there's a theorem here and then I proved + + + align:start position:0% +there's a theorem here and then I proved +oh yeah it's got to change parody so + + align:start position:0% +oh yeah it's got to change parody so + + + align:start position:0% +oh yeah it's got to change parody so +what we ended up doing was adding a row + + align:start position:0% +what we ended up doing was adding a row + + + align:start position:0% +what we ended up doing was adding a row +down here uh make this path slightly + + align:start position:0% +down here uh make this path slightly + + + align:start position:0% +down here uh make this path slightly +longer that that adds exactly one + + align:start position:0% +longer that that adds exactly one + + + align:start position:0% +longer that that adds exactly one +uncovered pixel so it should fix the + + align:start position:0% +uncovered pixel so it should fix the + + + align:start position:0% +uncovered pixel so it should fix the +parody problem uh many hours later we + + align:start position:0% +parody problem uh many hours later we + + + align:start position:0% +parody problem uh many hours later we +came up with this um so this is good + + align:start position:0% +came up with this um so this is good + + + align:start position:0% +came up with this um so this is good +every pixel is covered in all four cases + + align:start position:0% +every pixel is covered in all four cases + + + align:start position:0% +every pixel is covered in all four cases +so we have the bottom row is that the + + align:start position:0% +so we have the bottom row is that the + + + align:start position:0% +so we have the bottom row is that the +top the CLA path is in and the top row + + align:start position:0% +top the CLA path is in and the top row + + + align:start position:0% +top the CLA path is in and the top row +is the CLA path is out and as you can + + align:start position:0% +is the CLA path is out and as you can + + + align:start position:0% +is the CLA path is out and as you can +see lots of careful orientations of + + align:start position:0% +see lots of careful orientations of + + + align:start position:0% +see lots of careful orientations of +these little terminal pairs to make sure + + align:start position:0% +these little terminal pairs to make sure + + + align:start position:0% +these little terminal pairs to make sure +in all cases you can cover everything + + align:start position:0% +in all cases you can cover everything + + + align:start position:0% +in all cases you can cover everything +this is frustrating because you fixed + + align:start position:0% +this is frustrating because you fixed + + + align:start position:0% +this is frustrating because you fixed +one and then you switch to the other + + align:start position:0% +one and then you switch to the other + + + align:start position:0% +one and then you switch to the other +layer and say oh I broke this other one + + align:start position:0% +layer and say oh I broke this other one + + + align:start position:0% +layer and say oh I broke this other one +I rotated these guys and now it's not + + align:start position:0% +I rotated these guys and now it's not + + + align:start position:0% +I rotated these guys and now it's not +possible to do this so you better and it + + align:start position:0% +possible to do this so you better and it + + + align:start position:0% +possible to do this so you better and it +would be like you rotate this and then + + align:start position:0% +would be like you rotate this and then + + + align:start position:0% +would be like you rotate this and then +rotate that and rotate this and you + + align:start position:0% +rotate that and rotate this and you + + + align:start position:0% +rotate that and rotate this and you +luckily no bad Cycles happen you could + + align:start position:0% +luckily no bad Cycles happen you could + + + align:start position:0% +luckily no bad Cycles happen you could +always resolve it and so finally we got + + align:start position:0% +always resolve it and so finally we got + + + align:start position:0% +always resolve it and so finally we got +this + + align:start position:0% +this + + + align:start position:0% +this +picture except for issue three uh which + + align:start position:0% +picture except for issue three uh which + + + align:start position:0% +picture except for issue three uh which +is another parody problem it's blown + + align:start position:0% +is another parody problem it's blown + + + align:start position:0% +is another parody problem it's blown +away it's like every day uh there was + + align:start position:0% +away it's like every day uh there was + + + align:start position:0% +away it's like every day uh there was +another parody problem wri of course the + + align:start position:0% +another parody problem wri of course the + + + align:start position:0% +another parody problem wri of course the +deadline is like tomorrow at this point + + align:start position:0% +deadline is like tomorrow at this point + + + align:start position:0% +deadline is like tomorrow at this point +luckily I started three days ahead + + align:start position:0% +luckily I started three days ahead + + + align:start position:0% +luckily I started three days ahead +so there were exactly three + + align:start position:0% +so there were exactly three + + + align:start position:0% +so there were exactly three +issues so uh remember this gadget which + + align:start position:0% +issues so uh remember this gadget which + + + align:start position:0% +issues so uh remember this gadget which +was the choice uh I didn't say this is + + align:start position:0% +was the choice uh I didn't say this is + + + align:start position:0% +was the choice uh I didn't say this is +like a variable choice you have two + + align:start position:0% +like a variable choice you have two + + + align:start position:0% +like a variable choice you have two +choices if you want a clause choice you + + align:start position:0% +choices if you want a clause choice you + + + align:start position:0% +choices if you want a clause choice you +connect two of these gadgets together + + align:start position:0% +connect two of these gadgets together + + + align:start position:0% +connect two of these gadgets together +and then you have three different paths + + align:start position:0% +and then you have three different paths + + + align:start position:0% +and then you have three different paths +you might follow if you stare at this + + align:start position:0% +you might follow if you stare at this + + + align:start position:0% +you might follow if you stare at this +enough and I just wanted to make sure + + align:start position:0% +enough and I just wanted to make sure + + + align:start position:0% +enough and I just wanted to make sure +okay can I plug these together I thought + + align:start position:0% +okay can I plug these together I thought + + + align:start position:0% +okay can I plug these together I thought +okay I'll just copy the paste and lay + + align:start position:0% +okay I'll just copy the paste and lay + + + align:start position:0% +okay I'll just copy the paste and lay +things out and I had a parity problem + + align:start position:0% +things out and I had a parity problem + + + align:start position:0% +things out and I had a parity problem +it's like oh man what's going on well if + + align:start position:0% +it's like oh man what's going on well if + + + align:start position:0% +it's like oh man what's going on well if +you look here uh this is at one column + + align:start position:0% +you look here uh this is at one column + + + align:start position:0% +you look here uh this is at one column +and this is a column uh four positions + + align:start position:0% +and this is a column uh four positions + + + align:start position:0% +and this is a column uh four positions +over so in particular the two choices + + align:start position:0% +over so in particular the two choices + + + align:start position:0% +over so in particular the two choices +here uh have the same parody I don't I + + align:start position:0% +here uh have the same parody I don't I + + + align:start position:0% +here uh have the same parody I don't I +think it's mod two not mod four but + + align:start position:0% +think it's mod two not mod four but + + + align:start position:0% +think it's mod two not mod four but +could double check uh and you just + + align:start position:0% +could double check uh and you just + + + align:start position:0% +could double check uh and you just +cannot build this if you want these + + align:start position:0% +cannot build this if you want these + + + align:start position:0% +cannot build this if you want these +things to be in odd distance apart + + align:start position:0% +things to be in odd distance apart + + + align:start position:0% +things to be in odd distance apart +um cuz parody so and then you look at + + align:start position:0% +um cuz parody so and then you look at + + + align:start position:0% +um cuz parody so and then you look at +this gadget and you realize it has an + + align:start position:0% +this gadget and you realize it has an + + + align:start position:0% +this gadget and you realize it has an +odd number of columns we made it an even + + align:start position:0% +odd number of columns we made it an even + + + align:start position:0% +odd number of columns we made it an even +number of rows when we added that last + + align:start position:0% +number of rows when we added that last + + + align:start position:0% +number of rows when we added that last +row uh but now it has an odd number of + + align:start position:0% +row uh but now it has an odd number of + + + align:start position:0% +row uh but now it has an odd number of +columns which is kind of weird but + + align:start position:0% +columns which is kind of weird but + + + align:start position:0% +columns which is kind of weird but +that's life so uh we need to make it + + align:start position:0% +that's life so uh we need to make it + + + align:start position:0% +that's life so uh we need to make it +even and so I think if you focus right + + align:start position:0% +even and so I think if you focus right + + + align:start position:0% +even and so I think if you focus right +here we add another column sorry it's + + align:start position:0% +here we add another column sorry it's + + + align:start position:0% +here we add another column sorry it's +now right here so there used to be two + + align:start position:0% +now right here so there used to be two + + + align:start position:0% +now right here so there used to be two +now now there are three we have this + + align:start position:0% +now now there are three we have this + + + align:start position:0% +now now there are three we have this +little trick to kind of fill things in + + align:start position:0% +little trick to kind of fill things in + + + align:start position:0% +little trick to kind of fill things in +and not too much changed I think I also + + align:start position:0% +and not too much changed I think I also + + + align:start position:0% +and not too much changed I think I also +cleaned up the gadget I removed a couple + + align:start position:0% +cleaned up the gadget I removed a couple + + + align:start position:0% +cleaned up the gadget I removed a couple +extra columns on the right but the key + + align:start position:0% +extra columns on the right but the key + + + align:start position:0% +extra columns on the right but the key +thing was to add a new column uh that + + align:start position:0% +thing was to add a new column uh that + + + align:start position:0% +thing was to add a new column uh that +fixed the par now the number of columns + + align:start position:0% +fixed the par now the number of columns + + + align:start position:0% +fixed the par now the number of columns +is even and now you have to prove this + + align:start position:0% +is even and now you have to prove this + + + align:start position:0% +is even and now you have to prove this +but it's pretty easy to check you can + + align:start position:0% +but it's pretty easy to check you can + + + align:start position:0% +but it's pretty easy to check you can +plug it into you can combine these + + align:start position:0% +plug it into you can combine these + + + align:start position:0% +plug it into you can combine these +gadgets together and uh they match up + + align:start position:0% +gadgets together and uh they match up + + + align:start position:0% +gadgets together and uh they match up +and then if you have blank space it's + + align:start position:0% +and then if you have blank space it's + + + align:start position:0% +and then if you have blank space it's +also even by even and so you it always + + align:start position:0% +also even by even and so you it always + + + align:start position:0% +also even by even and so you it always +has a perfect matching and so you can + + align:start position:0% +has a perfect matching and so you can + + + align:start position:0% +has a perfect matching and so you can +fill in any blank space with extra + + align:start position:0% + + + + align:start position:0% + +pairs those are the + + align:start position:0% +pairs those are the + + + align:start position:0% +pairs those are the +gadgets + + align:start position:0% +gadgets + + + align:start position:0% +gadgets +except uh there's one more issue I + + align:start position:0% +except uh there's one more issue I + + + align:start position:0% +except uh there's one more issue I +haven't mentioned yeah there's a parody + + align:start position:0% +haven't mentioned yeah there's a parody + + + align:start position:0% +haven't mentioned yeah there's a parody +problem with your parody problems + + align:start position:0% +problem with your parody problems + + + align:start position:0% +problem with your parody problems +there's only an odd number of only an + + align:start position:0% +there's only an odd number of only an + + + align:start position:0% +there's only an odd number of only an +odd number of parody problems luckily + + align:start position:0% +odd number of parody problems luckily + + + align:start position:0% +odd number of parody problems luckily +the next problem is not a parody problem + + align:start position:0% +the next problem is not a parody problem + + + align:start position:0% +the next problem is not a parody problem +or unluck I don't know yeah um and this + + align:start position:0% +or unluck I don't know yeah um and this + + + align:start position:0% +or unluck I don't know yeah um and this +it wasn't really a problem I knew it was + + align:start position:0% +it wasn't really a problem I knew it was + + + align:start position:0% +it wasn't really a problem I knew it was +going to happen I just had to draw the + + align:start position:0% +going to happen I just had to draw the + + + align:start position:0% +going to happen I just had to draw the +figure uh but it's good for exercise + + align:start position:0% +figure uh but it's good for exercise + + + align:start position:0% +figure uh but it's good for exercise +think about what what could possibly be + + align:start position:0% +think about what what could possibly be + + + align:start position:0% +think about what what could possibly be +missing we've spent all this time doing + + align:start position:0% +missing we've spent all this time doing + + + align:start position:0% +missing we've spent all this time doing +crossover gadgets but there's also the + + align:start position:0% +crossover gadgets but there's also the + + + align:start position:0% +crossover gadgets but there's also the +case where the wires cross and we + + align:start position:0% +case where the wires cross and we + + + align:start position:0% +case where the wires cross and we +actually want the vertical wire to block + + align:start position:0% +actually want the vertical wire to block + + + align:start position:0% +actually want the vertical wire to block +the horizontal wire in a particular + + align:start position:0% +the horizontal wire in a particular + + + align:start position:0% +the horizontal wire in a particular +choice this is actually really easy to + + align:start position:0% +choice this is actually really easy to + + + align:start position:0% +choice this is actually really easy to +do so here's the the gadget I was just + + align:start position:0% +do so here's the the gadget I was just + + + align:start position:0% +do so here's the the gadget I was just +showing you without all the stuff filled + + align:start position:0% +showing you without all the stuff filled + + + align:start position:0% +showing you without all the stuff filled +in those are just the terminal Pairs and + + align:start position:0% +in those are just the terminal Pairs and + + + align:start position:0% +in those are just the terminal Pairs and +you know this guy goes to the left this + + align:start position:0% +you know this guy goes to the left this + + + align:start position:0% +you know this guy goes to the left this +guy goes to here this guy goes to the + + align:start position:0% +guy goes to here this guy goes to the + + + align:start position:0% +guy goes to here this guy goes to the +right um if you just add in an extra + + align:start position:0% +right um if you just add in an extra + + + align:start position:0% +right um if you just add in an extra +pair here or an extra pair here you will + + align:start position:0% +pair here or an extra pair here you will + + + align:start position:0% +pair here or an extra pair here you will +block blue or red correspondingly so if + + align:start position:0% +block blue or red correspondingly so if + + + align:start position:0% +block blue or red correspondingly so if +we go to the previous slide here blue + + align:start position:0% +we go to the previous slide here blue + + + align:start position:0% +we go to the previous slide here blue +goes through this position but red does + + align:start position:0% +goes through this position but red does + + + align:start position:0% +goes through this position but red does +not and uh down here uh blue does not go + + align:start position:0% +not and uh down here uh blue does not go + + + align:start position:0% +not and uh down here uh blue does not go +through this position but red does and + + align:start position:0% +through this position but red does and + + + align:start position:0% +through this position but red does and +so if you add in this extra little pair + + align:start position:0% +so if you add in this extra little pair + + + align:start position:0% +so if you add in this extra little pair +you will force red or blue at that + + align:start position:0% +you will force red or blue at that + + + align:start position:0% +you will force red or blue at that +intersection and that was the little + + align:start position:0% +intersection and that was the little + + + align:start position:0% +intersection and that was the little +squares in the overall diagram so if you + + align:start position:0% +squares in the overall diagram so if you + + + align:start position:0% +squares in the overall diagram so if you +choose this vertical path you force the + + align:start position:0% +choose this vertical path you force the + + + align:start position:0% +choose this vertical path you force the +horizontal path to be the other + + align:start position:0% +horizontal path to be the other + + + align:start position:0% +horizontal path to be the other +thing that's the + + align:start position:0% +thing that's the + + + align:start position:0% +thing that's the +proof I hope there are no more + + align:start position:0% +proof I hope there are no more + + + align:start position:0% +proof I hope there are no more +issues uh but it was it was exciting so + + align:start position:0% +issues uh but it was it was exciting so + + + align:start position:0% +issues uh but it was it was exciting so +just to give you a flavor for parody + + align:start position:0% +just to give you a flavor for parody + + + align:start position:0% +just to give you a flavor for parody +issues they are all over the place + + align:start position:0% +issues they are all over the place + + + align:start position:0% +issues they are all over the place +especially when you're on a grid be + + align:start position:0% +especially when you're on a grid be + + + align:start position:0% +especially when you're on a grid be +careful of them that's the life lesson + + align:start position:0% +careful of them that's the life lesson + + + align:start position:0% +careful of them that's the life lesson +um I'll tell you a little bit about + + align:start position:0% +um I'll tell you a little bit about + + + align:start position:0% +um I'll tell you a little bit about +where this kind of problem comes from + + align:start position:0% +where this kind of problem comes from + + + align:start position:0% +where this kind of problem comes from +the earliest reference we know is by Sam + + align:start position:0% +the earliest reference we know is by Sam + + + align:start position:0% +the earliest reference we know is by Sam +Lloyd famous puzzle designer in 1897 he + + align:start position:0% +Lloyd famous puzzle designer in 1897 he + + + align:start position:0% +Lloyd famous puzzle designer in 1897 he +he posed this puzzle incredibly + + align:start position:0% +he posed this puzzle incredibly + + + align:start position:0% +he posed this puzzle incredibly +complicated puzzle I mean lots of stuff + + align:start position:0% +complicated puzzle I mean lots of stuff + + + align:start position:0% +complicated puzzle I mean lots of stuff +in it um and then I think the next issue + + align:start position:0% +in it um and then I think the next issue + + + align:start position:0% +in it um and then I think the next issue +he published the solution which is this + + align:start position:0% +he published the solution which is this + + + align:start position:0% +he published the solution which is this +um hopefully I remember the problem so + + align:start position:0% +um hopefully I remember the problem so + + + align:start position:0% +um hopefully I remember the problem so +you have these houses and you'll notice + + align:start position:0% +you have these houses and you'll notice + + + align:start position:0% +you have these houses and you'll notice +each house faces an + + align:start position:0% +each house faces an + + + align:start position:0% +each house faces an +exit and uh what you'd like is for each + + align:start position:0% +exit and uh what you'd like is for each + + + align:start position:0% +exit and uh what you'd like is for each +house to be connected via Pathway to the + + align:start position:0% +house to be connected via Pathway to the + + + align:start position:0% +house to be connected via Pathway to the +exit um but if you just did that that + + align:start position:0% +exit um but if you just did that that + + + align:start position:0% +exit um but if you just did that that +they would intersect each other so you + + align:start position:0% +they would intersect each other so you + + + align:start position:0% +they would intersect each other so you +want vertex disjoint paths in the grid + + align:start position:0% +want vertex disjoint paths in the grid + + + align:start position:0% +want vertex disjoint paths in the grid +from the houses to the exit that they + + align:start position:0% +from the houses to the exit that they + + + align:start position:0% +from the houses to the exit that they +face so that is a terminal pair vertex + + align:start position:0% +face so that is a terminal pair vertex + + + align:start position:0% +face so that is a terminal pair vertex +dis joint path problem now he didn't + + align:start position:0% +dis joint path problem now he didn't + + + align:start position:0% +dis joint path problem now he didn't +specify that those paths should fill the + + align:start position:0% +specify that those paths should fill the + + + align:start position:0% +specify that those paths should fill the +entire grid but they almost do other + + align:start position:0% +entire grid but they almost do other + + + align:start position:0% +entire grid but they almost do other +than this little corner uh they do and + + align:start position:0% +than this little corner uh they do and + + + align:start position:0% +than this little corner uh they do and +this you know a few little Corners at + + align:start position:0% +this you know a few little Corners at + + + align:start position:0% +this you know a few little Corners at +the extremes and you can fix it instead + + align:start position:0% +the extremes and you can fix it instead + + + align:start position:0% +the extremes and you can fix it instead +of going like this you can go Zig Zig + + align:start position:0% +of going like this you can go Zig Zig + + + align:start position:0% +of going like this you can go Zig Zig +Zig Zig and Zig Zig Zig Zig Zig and uh + + align:start position:0% +Zig Zig and Zig Zig Zig Zig Zig and uh + + + align:start position:0% +Zig Zig and Zig Zig Zig Zig Zig and uh +make it into a solution to the problem I + + align:start position:0% +make it into a solution to the problem I + + + align:start position:0% +make it into a solution to the problem I +just + + align:start position:0% +just + + + align:start position:0% +just +said okay so that's + + align:start position:0% +said okay so that's + + + align:start position:0% +said okay so that's +1897 um in modern terms this is known as + + align:start position:0% +1897 um in modern terms this is known as + + + align:start position:0% +1897 um in modern terms this is known as +the number link puzzle uh nickoli is a + + align:start position:0% +the number link puzzle uh nickoli is a + + + align:start position:0% +the number link puzzle uh nickoli is a +famous uh Japanese puzzle publisher + + align:start position:0% +famous uh Japanese puzzle publisher + + + align:start position:0% +famous uh Japanese puzzle publisher +these are two nickoli books that uh we + + align:start position:0% +these are two nickoli books that uh we + + + align:start position:0% +these are two nickoli books that uh we +got in our last trip to Japan a couple + + align:start position:0% +got in our last trip to Japan a couple + + + align:start position:0% +got in our last trip to Japan a couple +of months ago uh these are both for the + + align:start position:0% +of months ago uh these are both for the + + + align:start position:0% +of months ago uh these are both for the +number link puzzle so you turn to an + + align:start position:0% +number link puzzle so you turn to an + + + align:start position:0% +number link puzzle so you turn to an +arbitrary + + align:start position:0% +arbitrary + + + align:start position:0% +arbitrary +page and you have some + + align:start position:0% +page and you have some + + + align:start position:0% +page and you have some +uh picture like this which uh here's an + + align:start position:0% +uh picture like this which uh here's an + + + align:start position:0% +uh picture like this which uh here's an +example you have pairs you have a bunch + + align:start position:0% +example you have pairs you have a bunch + + + align:start position:0% +example you have pairs you have a bunch +of numbers and blank spaces the idea is + + align:start position:0% +of numbers and blank spaces the idea is + + + align:start position:0% +of numbers and blank spaces the idea is +that there's exactly two of each number + + align:start position:0% +that there's exactly two of each number + + + align:start position:0% +that there's exactly two of each number +those are your terminal pairs you want + + align:start position:0% +those are your terminal pairs you want + + + align:start position:0% +those are your terminal pairs you want +to find vertex dis joint paths that + + align:start position:0% +to find vertex dis joint paths that + + + align:start position:0% +to find vertex dis joint paths that +connect them and yeah in the back + + align:start position:0% +connect them and yeah in the back + + + align:start position:0% +connect them and yeah in the back +there's Solutions so if you can't solve + + align:start position:0% +there's Solutions so if you can't solve + + + align:start position:0% +there's Solutions so if you can't solve +one um they have easy ones medium ones + + align:start position:0% +one um they have easy ones medium ones + + + align:start position:0% +one um they have easy ones medium ones +hard ones uh so how hard is it and P + + align:start position:0% +hard ones uh so how hard is it and P + + + align:start position:0% +hard ones uh so how hard is it and P +hard uh because this is exactly the + + align:start position:0% +hard uh because this is exactly the + + + align:start position:0% +hard uh because this is exactly the +problem we were just solving if you want + + align:start position:0% +problem we were just solving if you want + + + align:start position:0% +problem we were just solving if you want +to find ver + + align:start position:0% +to find ver + + + align:start position:0% +to find ver +just trint paths in the grid um there is + + align:start position:0% +just trint paths in the grid um there is + + + align:start position:0% +just trint paths in the grid um there is +this issue of whether you are specified + + align:start position:0% +this issue of whether you are specified + + + align:start position:0% +this issue of whether you are specified +as one of the constraints that you must + + align:start position:0% +as one of the constraints that you must + + + align:start position:0% +as one of the constraints that you must +um visit every square + + align:start position:0% +um visit every square + + + align:start position:0% +um visit every square +but do a quick quick visual scan here + + align:start position:0% +but do a quick quick visual scan here + + + align:start position:0% +but do a quick quick visual scan here +and every solution that I see every + + align:start position:0% +and every solution that I see every + + + align:start position:0% +and every solution that I see every +Square happens to be + + align:start position:0% +Square happens to be + + + align:start position:0% +Square happens to be +filled okay now that might be the way + + align:start position:0% +filled okay now that might be the way + + + align:start position:0% +filled okay now that might be the way +that they design the puzzles the only + + align:start position:0% +that they design the puzzles the only + + + align:start position:0% +that they design the puzzles the only +way to solve them is for the every + + align:start position:0% +way to solve them is for the every + + + align:start position:0% +way to solve them is for the every +Square squ to be filled or it might be + + align:start position:0% +Square squ to be filled or it might be + + + align:start position:0% +Square squ to be filled or it might be +that's a constraint to the puzzle and + + align:start position:0% +that's a constraint to the puzzle and + + + align:start position:0% +that's a constraint to the puzzle and +different writeups suggest different + + align:start position:0% +different writeups suggest different + + + align:start position:0% +different writeups suggest different +ways but what we proved is both ways + + align:start position:0% +ways but what we proved is both ways + + + align:start position:0% +ways but what we proved is both ways +it's hard whether you give that as a + + align:start position:0% +it's hard whether you give that as a + + + align:start position:0% +it's hard whether you give that as a +specification or you make it possible to + + align:start position:0% +specification or you make it possible to + + + align:start position:0% +specification or you make it possible to +do uh it it is NP hard because we + + align:start position:0% +do uh it it is NP hard because we + + + align:start position:0% +do uh it it is NP hard because we +started from a reduction that didn't + + align:start position:0% +started from a reduction that didn't + + + align:start position:0% +started from a reduction that didn't +have to fill every pixel and we turn it + + align:start position:0% +have to fill every pixel and we turn it + + + align:start position:0% +have to fill every pixel and we turn it +into one that could fill every pixel if + + align:start position:0% +into one that could fill every pixel if + + + align:start position:0% +into one that could fill every pixel if +you wanted so yeah there's a sense in + + align:start position:0% +you wanted so yeah there's a sense in + + + align:start position:0% +you wanted so yeah there's a sense in +which these puzzles are sparer in terms + + align:start position:0% +which these puzzles are sparer in terms + + + align:start position:0% +which these puzzles are sparer in terms +of the number of vertices than your + + align:start position:0% +of the number of vertices than your + + + align:start position:0% +of the number of vertices than your +reduction is it possible that you could + + align:start position:0% +reduction is it possible that you could + + + align:start position:0% +reduction is it possible that you could +Define it in such a way that these are + + align:start position:0% +Define it in such a way that these are + + + align:start position:0% +Define it in such a way that these are +polom solvable it's an interesting + + align:start position:0% +polom solvable it's an interesting + + + align:start position:0% +polom solvable it's an interesting +question um so our our reduction has + + align:start position:0% +question um so our our reduction has + + + align:start position:0% +question um so our our reduction has +most of the cells filled with terminal + + align:start position:0% +most of the cells filled with terminal + + + align:start position:0% +most of the cells filled with terminal +filled with numbers um these you could + + align:start position:0% +filled with numbers um these you could + + + align:start position:0% +filled with numbers um these you could +say if you have an N byn grid maybe + + align:start position:0% +say if you have an N byn grid maybe + + + align:start position:0% +say if you have an N byn grid maybe +these only have order n numbers whereas + + align:start position:0% +these only have order n numbers whereas + + + align:start position:0% +these only have order n numbers whereas +we have order n squ numbers that would + + align:start position:0% +we have order n squ numbers that would + + + align:start position:0% +we have order n squ numbers that would +be interesting I don't know the + + align:start position:0% +be interesting I don't know the + + + align:start position:0% +be interesting I don't know the +complexity the one thing that's known as + + align:start position:0% +complexity the one thing that's known as + + + align:start position:0% +complexity the one thing that's known as +for one terminal pair it's polinomial + + align:start position:0% +for one terminal pair it's polinomial + + + align:start position:0% +for one terminal pair it's polinomial +time I think even two terminal pairs is + + align:start position:0% +time I think even two terminal pairs is + + + align:start position:0% +time I think even two terminal pairs is +an open problem so that would be you + + align:start position:0% +an open problem so that would be you + + + align:start position:0% +an open problem so that would be you +need to solve that before you could + + align:start position:0% +need to solve that before you could + + + align:start position:0% +need to solve that before you could +solve n terminal pairs SP an N + + align:start position:0% +solve n terminal pairs SP an N + + + align:start position:0% +solve n terminal pairs SP an N +byn uh so I don't know how many people + + align:start position:0% +byn uh so I don't know how many people + + + align:start position:0% +byn uh so I don't know how many people +worked on Tu terminal pairs I thought + + align:start position:0% +worked on Tu terminal pairs I thought + + + align:start position:0% +worked on Tu terminal pairs I thought +about a little bit it seems very + + align:start position:0% +about a little bit it seems very + + + align:start position:0% +about a little bit it seems very +difficult uh anyway little more to this + + align:start position:0% +difficult uh anyway little more to this + + + align:start position:0% +difficult uh anyway little more to this +story um we first in fact we first + + align:start position:0% +story um we first in fact we first + + + align:start position:0% +story um we first in fact we first +encountered number Link in the form of + + align:start position:0% +encountered number Link in the form of + + + align:start position:0% +encountered number Link in the form of +an Android game called Flow Free which + + align:start position:0% +an Android game called Flow Free which + + + align:start position:0% +an Android game called Flow Free which +some of you may have played it was it + + align:start position:0% +some of you may have played it was it + + + align:start position:0% +some of you may have played it was it +became popular for a few months there um + + align:start position:0% +became popular for a few months there um + + + align:start position:0% +became popular for a few months there um +and but it is exactly number link as + + align:start position:0% +and but it is exactly number link as + + + align:start position:0% +and but it is exactly number link as +I've defined it and once you know that + + align:start position:0% +I've defined it and once you know that + + + align:start position:0% +I've defined it and once you know that +uh then you there's also number link and + + align:start position:0% +uh then you there's also number link and + + + align:start position:0% +uh then you there's also number link and +a zillion other clones and I don't think + + align:start position:0% +a zillion other clones and I don't think + + + align:start position:0% +a zillion other clones and I don't think +nickol Le publishes any of these so but + + align:start position:0% +nickol Le publishes any of these so but + + + align:start position:0% +nickol Le publishes any of these so but +it's all from 1897 so unclear what the + + align:start position:0% +it's all from 1897 so unclear what the + + + align:start position:0% +it's all from 1897 so unclear what the +copyright is here um uh but in + + align:start position:0% +copyright is here um uh but in + + + align:start position:0% +copyright is here um uh but in +particular number link I like it has the + + align:start position:0% +particular number link I like it has the + + + align:start position:0% +particular number link I like it has the +nicest gooey uh but in the beginning + + align:start position:0% +nicest gooey uh but in the beginning + + + align:start position:0% +nicest gooey uh but in the beginning +tutorial it says well there's actually + + align:start position:0% +tutorial it says well there's actually + + + align:start position:0% +tutorial it says well there's actually +two modes you can play there's zigzag + + align:start position:0% +two modes you can play there's zigzag + + + align:start position:0% +two modes you can play there's zigzag +mode where you can draw pads however you + + align:start position:0% +mode where you can draw pads however you + + + align:start position:0% +mode where you can draw pads however you +want that's what I've been talking about + + align:start position:0% +want that's what I've been talking about + + + align:start position:0% +want that's what I've been talking about +CU graph theoretically that's the + + align:start position:0% +CU graph theoretically that's the + + + align:start position:0% +CU graph theoretically that's the +natural thing thing then there's this + + align:start position:0% +natural thing thing then there's this + + + align:start position:0% +natural thing thing then there's this +other Mode called classic mode where uh + + align:start position:0% +other Mode called classic mode where uh + + + align:start position:0% +other Mode called classic mode where uh +whenever if you draw a complicated path + + align:start position:0% +whenever if you draw a complicated path + + + align:start position:0% +whenever if you draw a complicated path +it gets short Auto shrinked is the + + align:start position:0% +it gets short Auto shrinked is the + + + align:start position:0% +it gets short Auto shrinked is the +technical term uh now again it's hard to + + align:start position:0% +technical term uh now again it's hard to + + + align:start position:0% +technical term uh now again it's hard to +have an authority here on like what are + + align:start position:0% +have an authority here on like what are + + + align:start position:0% +have an authority here on like what are +the rules of number link uh but one + + align:start position:0% +the rules of number link uh but one + + + align:start position:0% +the rules of number link uh but one +definition is you consider all possible + + align:start position:0% +definition is you consider all possible + + + align:start position:0% +definition is you consider all possible +paths uh between these pairs that have + + align:start position:0% +paths uh between these pairs that have + + + align:start position:0% +paths uh between these pairs that have +the same topology like you could try to + + align:start position:0% +the same topology like you could try to + + + align:start position:0% +the same topology like you could try to +go you can try to go this way or you + + align:start position:0% +go you can try to go this way or you + + + align:start position:0% +go you can try to go this way or you +could try to go this way here you have + + align:start position:0% +could try to go this way here you have + + + align:start position:0% +could try to go this way here you have +these two guys on your right hand side + + align:start position:0% +these two guys on your right hand side + + + align:start position:0% +these two guys on your right hand side +here you have them on the left hand side + + align:start position:0% +here you have them on the left hand side + + + align:start position:0% +here you have them on the left hand side +in general that's called the homotopy + + align:start position:0% +in general that's called the homotopy + + + align:start position:0% +in general that's called the homotopy +type of that path consider all paths + + align:start position:0% +type of that path consider all paths + + + align:start position:0% +type of that path consider all paths +with the same homotopy path homotopy + + align:start position:0% +with the same homotopy path homotopy + + + align:start position:0% +with the same homotopy path homotopy +type your path should be shortest among + + align:start position:0% +type your path should be shortest among + + + align:start position:0% +type your path should be shortest among +all such paths that is one notion of + + align:start position:0% +all such paths that is one notion of + + + align:start position:0% +all such paths that is one notion of +Auto shrink I don't know if that's the + + align:start position:0% +Auto shrink I don't know if that's the + + + align:start position:0% +Auto shrink I don't know if that's the +official one but it is a that has to do + + align:start position:0% +official one but it is a that has to do + + + align:start position:0% +official one but it is a that has to do +the order in which you set the things + + align:start position:0% +the order in which you set the things + + + align:start position:0% +the order in which you set the things +this description suggests a particular + + align:start position:0% +this description suggests a particular + + + align:start position:0% +this description suggests a particular +order yeah uh so you'd also maybe need a + + align:start position:0% +order yeah uh so you'd also maybe need a + + + align:start position:0% +order yeah uh so you'd also maybe need a +proper ordering yeah so there's the one + + align:start position:0% +proper ordering yeah so there's the one + + + align:start position:0% +proper ordering yeah so there's the one +to the one here there's + + align:start position:0% +to the one here there's + + + align:start position:0% +to the one here there's +multiple ways to well the other way + + align:start position:0% +multiple ways to well the other way + + + align:start position:0% +multiple ways to well the other way +there's multiple ways to get through + + align:start position:0% +there's multiple ways to get through + + + align:start position:0% +there's multiple ways to get through +that square grid I think you can go down + + align:start position:0% +that square grid I think you can go down + + + align:start position:0% +that square grid I think you can go down +and all the way around or you can go + + align:start position:0% +and all the way around or you can go + + + align:start position:0% +and all the way around or you can go +right these would both be the same + + align:start position:0% +right these would both be the same + + + align:start position:0% +right these would both be the same +length and I think those are both + + align:start position:0% +length and I think those are both + + + align:start position:0% +length and I think those are both +considered valid although you have to + + align:start position:0% +considered valid although you have to + + + align:start position:0% +considered valid although you have to +play this particular wouldn't either of + + align:start position:0% +play this particular wouldn't either of + + + align:start position:0% +play this particular wouldn't either of +those it would take the one you chose + + align:start position:0% +those it would take the one you chose + + + align:start position:0% +those it would take the one you chose +right okay so you have still have some + + align:start position:0% +right okay so you have still have some + + + align:start position:0% +right okay so you have still have some +flexibility there are multiple shortest + + align:start position:0% +flexibility there are multiple shortest + + + align:start position:0% +flexibility there are multiple shortest +paths in this world because we're + + align:start position:0% +paths in this world because we're + + + align:start position:0% +paths in this world because we're +Manhattan + + align:start position:0% +Manhattan + + + align:start position:0% +Manhattan +metric uh so this raises the issue of Cl + + align:start position:0% +metric uh so this raises the issue of Cl + + + align:start position:0% +metric uh so this raises the issue of Cl +classic number link and most of the + + align:start position:0% +classic number link and most of the + + + align:start position:0% +classic number link and most of the +puzzles I think all the puzzles I + + align:start position:0% +puzzles I think all the puzzles I + + + align:start position:0% +puzzles I think all the puzzles I +haven't checked every single one + + align:start position:0% +haven't checked every single one + + + align:start position:0% +haven't checked every single one +actually follow these rules uh but again + + align:start position:0% +actually follow these rules uh but again + + + align:start position:0% +actually follow these rules uh but again +I I'm not clear what the rules actually + + align:start position:0% +I I'm not clear what the rules actually + + + align:start position:0% +I I'm not clear what the rules actually +are whether they require this or this uh + + align:start position:0% +are whether they require this or this uh + + + align:start position:0% +are whether they require this or this uh +but luckily there's another paper that + + align:start position:0% +but luckily there's another paper that + + + align:start position:0% +but luckily there's another paper that +covers that case uh it's in Japanese but + + align:start position:0% +covers that case uh it's in Japanese but + + + align:start position:0% +covers that case uh it's in Japanese but +it uh sets up uh the ru + + align:start position:0% +it uh sets up uh the ru + + + align:start position:0% +it uh sets up uh the ru +a it considers the model where you the + + align:start position:0% +a it considers the model where you the + + + align:start position:0% +a it considers the model where you the +classic mode where you have to uh do + + align:start position:0% +classic mode where you have to uh do + + + align:start position:0% +classic mode where you have to uh do +some kind of locally shortest paths and + + align:start position:0% +some kind of locally shortest paths and + + + align:start position:0% +some kind of locally shortest paths and +the gadgets critically exploit that + + align:start position:0% +the gadgets critically exploit that + + + align:start position:0% +the gadgets critically exploit that +feature uh it's a reduction from planer + + align:start position:0% +feature uh it's a reduction from planer + + + align:start position:0% +feature uh it's a reduction from planer +3at we might look at it when we get to + + align:start position:0% +3at we might look at it when we get to + + + align:start position:0% +3at we might look at it when we get to +planer 3at which is the next class or + + align:start position:0% +planer 3at which is the next class or + + + align:start position:0% +planer 3at which is the next class or +two uh or not there's a ton of planer + + align:start position:0% +two uh or not there's a ton of planer + + + align:start position:0% +two uh or not there's a ton of planer +threat proofs but anyway that's been + + align:start position:0% +threat proofs but anyway that's been + + + align:start position:0% +threat proofs but anyway that's been +covered already the actual order of + + align:start position:0% +covered already the actual order of + + + align:start position:0% +covered already the actual order of +events is we proved our result and then + + align:start position:0% +events is we proved our result and then + + + align:start position:0% +events is we proved our result and then +we're like uh oh this is number link uh + + align:start position:0% +we're like uh oh this is number link uh + + + align:start position:0% +we're like uh oh this is number link uh +oh number link is MP complete and that + + align:start position:0% +oh number link is MP complete and that + + + align:start position:0% +oh number link is MP complete and that +was known a few years ago oh good thing + + align:start position:0% +was known a few years ago oh good thing + + + align:start position:0% +was known a few years ago oh good thing +it's a different game that we studed uh + + align:start position:0% +it's a different game that we studed uh + + + align:start position:0% +it's a different game that we studed uh +so there are two versions of number link + + align:start position:0% +so there are two versions of number link + + + align:start position:0% +so there are two versions of number link +now they're both heart so that's the + + align:start position:0% +now they're both heart so that's the + + + align:start position:0% +now they're both heart so that's the +good news and that's all for + + align:start position:0% +good news and that's all for + + + align:start position:0% +good news and that's all for +today this is the Super Mario Brothers + + align:start position:0% +today this is the Super Mario Brothers + + + align:start position:0% +today this is the Super Mario Brothers +edition of + + align:start position:0% + + + + align:start position:0% \ No newline at end of file diff --git a/eO3RNUAFtDE.txt b/eO3RNUAFtDE.txt new file mode 100644 index 0000000000000000000000000000000000000000..3e7afc03a02d2b273d387ad8e1bb4b2afd03ec18 --- /dev/null +++ b/eO3RNUAFtDE.txt @@ -0,0 +1,10595 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT open courseware continue + + align:start position:0% +will help MIT open courseware continue + + + align:start position:0% +will help MIT open courseware continue +to offer highquality educational + + align:start position:0% +to offer highquality educational + + + align:start position:0% +to offer highquality educational +resources for free to make a donation or + + align:start position:0% +resources for free to make a donation or + + + align:start position:0% +resources for free to make a donation or +view additional materials from hundreds + + align:start position:0% +view additional materials from hundreds + + + align:start position:0% +view additional materials from hundreds +of MIT courses visit MIT open courseware + + align:start position:0% +of MIT courses visit MIT open courseware + + + align:start position:0% +of MIT courses visit MIT open courseware +at + + align:start position:0% + + + + align:start position:0% + +ocw.mit.edu good evening people I've + + align:start position:0% +ocw.mit.edu good evening people I've + + + align:start position:0% +ocw.mit.edu good evening people I've +I've placed so much emphasis on + + align:start position:0% +I've placed so much emphasis on + + + align:start position:0% +I've placed so much emphasis on +Renard's camera because I think it so uh + + align:start position:0% +Renard's camera because I think it so uh + + + align:start position:0% +Renard's camera because I think it so uh +fundamentally expresses uh his sense of + + align:start position:0% +fundamentally expresses uh his sense of + + + align:start position:0% +fundamentally expresses uh his sense of +experience and if you become attentive + + align:start position:0% +experience and if you become attentive + + + align:start position:0% +experience and if you become attentive +to the really quiet and subtle ways in + + align:start position:0% +to the really quiet and subtle ways in + + + align:start position:0% +to the really quiet and subtle ways in +which renoir's camera is almost always + + align:start position:0% +which renoir's camera is almost always + + + align:start position:0% +which renoir's camera is almost always +in action is a part of the story in some + + align:start position:0% +in action is a part of the story in some + + + align:start position:0% +in action is a part of the story in some +sense uh you can begin to capture + + align:start position:0% +sense uh you can begin to capture + + + align:start position:0% +sense uh you can begin to capture +something of his importance in the + + align:start position:0% +something of his importance in the + + + align:start position:0% +something of his importance in the +history of Cinema uh because no director + + align:start position:0% +history of Cinema uh because no director + + + align:start position:0% +history of Cinema uh because no director +uh or Apprentice director who ever uh + + align:start position:0% +uh or Apprentice director who ever uh + + + align:start position:0% +uh or Apprentice director who ever uh +studied or looked at that uh renoir's + + align:start position:0% +studied or looked at that uh renoir's + + + align:start position:0% +studied or looked at that uh renoir's +films came away from it the same uh and + + align:start position:0% +films came away from it the same uh and + + + align:start position:0% +films came away from it the same uh and +his influence is almost impossible to + + align:start position:0% +his influence is almost impossible to + + + align:start position:0% +his influence is almost impossible to +fully measure there there are there are + + align:start position:0% +fully measure there there are there are + + + align:start position:0% +fully measure there there are there are +no uh cinematic Traditions after Renoir + + align:start position:0% +no uh cinematic Traditions after Renoir + + + align:start position:0% +no uh cinematic Traditions after Renoir +that haven't at least in some degree + + align:start position:0% +that haven't at least in some degree + + + align:start position:0% +that haven't at least in some degree +even if not directly then indirectly + + align:start position:0% +even if not directly then indirectly + + + align:start position:0% +even if not directly then indirectly +through other people who have been + + align:start position:0% +through other people who have been + + + align:start position:0% +through other people who have been +influenced by him uh um U been shaped by + + align:start position:0% +influenced by him uh um U been shaped by + + + align:start position:0% +influenced by him uh um U been shaped by +renoir's uh example and I wanted to give + + align:start position:0% +renoir's uh example and I wanted to give + + + align:start position:0% +renoir's uh example and I wanted to give +you one more instance of renoir's camera + + align:start position:0% +you one more instance of renoir's camera + + + align:start position:0% +you one more instance of renoir's camera +this from a film I've mentioned but not + + align:start position:0% +this from a film I've mentioned but not + + + align:start position:0% +this from a film I've mentioned but not +shown you it's from the last of his + + align:start position:0% +shown you it's from the last of his + + + align:start position:0% +shown you it's from the last of his +great French films some people many + + align:start position:0% +great French films some people many + + + align:start position:0% +great French films some people many +people would say it's his greatest film + + align:start position:0% +people would say it's his greatest film + + + align:start position:0% +people would say it's his greatest film +one of the great masterpieces in the + + align:start position:0% +one of the great masterpieces in the + + + align:start position:0% +one of the great masterpieces in the +history of movies the rules of the game + + align:start position:0% +history of movies the rules of the game + + + align:start position:0% +history of movies the rules of the game +the only reason I don't show it in our + + align:start position:0% +the only reason I don't show it in our + + + align:start position:0% +the only reason I don't show it in our +course is that it's in many ways a more + + align:start position:0% +course is that it's in many ways a more + + + align:start position:0% +course is that it's in many ways a more +difficult a more complex film than Grand + + align:start position:0% +difficult a more complex film than Grand + + + align:start position:0% +difficult a more complex film than Grand +Illusion and there's a there's a there's + + align:start position:0% +Illusion and there's a there's a there's + + + align:start position:0% +Illusion and there's a there's a there's +a grand Clarity or Simplicity of a + + align:start position:0% +a grand Clarity or Simplicity of a + + + align:start position:0% +a grand Clarity or Simplicity of a +certain kind not a Simplicity of + + align:start position:0% +certain kind not a Simplicity of + + + align:start position:0% +certain kind not a Simplicity of +character or of vision or of theme but a + + align:start position:0% +character or of vision or of theme but a + + + align:start position:0% +character or of vision or of theme but a +Simplicity of intention + + align:start position:0% +Simplicity of intention + + + align:start position:0% +Simplicity of intention +that becomes clear at least after the + + align:start position:0% +that becomes clear at least after the + + + align:start position:0% +that becomes clear at least after the +fact in Grand delusion it's a more + + align:start position:0% +fact in Grand delusion it's a more + + + align:start position:0% +fact in Grand delusion it's a more +accessible film especially for Americans + + align:start position:0% +accessible film especially for Americans + + + align:start position:0% +accessible film especially for Americans +I think uh the the uh the the rules of + + align:start position:0% +I think uh the the uh the the rules of + + + align:start position:0% +I think uh the the uh the the rules of +the game much more profoundly uh is + + align:start position:0% +the game much more profoundly uh is + + + align:start position:0% +the game much more profoundly uh is +a a meditation on the a theme that is + + align:start position:0% +a a meditation on the a theme that is + + + align:start position:0% +a a meditation on the a theme that is +also present in Grand Illusion as you'll + + align:start position:0% +also present in Grand Illusion as you'll + + + align:start position:0% +also present in Grand Illusion as you'll +see this evening uh the theme of + + align:start position:0% +see this evening uh the theme of + + + align:start position:0% +see this evening uh the theme of +historical transition but it's a much + + align:start position:0% +historical transition but it's a much + + + align:start position:0% +historical transition but it's a much +more complex and and uh extended medit + + align:start position:0% +more complex and and uh extended medit + + + align:start position:0% +more complex and and uh extended medit +on what was happening to French society + + align:start position:0% +on what was happening to French society + + + align:start position:0% +on what was happening to French society +uh in the in this in this immense + + align:start position:0% +uh in the in this in this immense + + + align:start position:0% +uh in the in this in this immense +transition that took place at the + + align:start position:0% +transition that took place at the + + + align:start position:0% +transition that took place at the +beginning of the 20th century + + align:start position:0% +beginning of the 20th century + + + align:start position:0% +beginning of the 20th century +essentially it's a transition as you'll + + align:start position:0% +essentially it's a transition as you'll + + + align:start position:0% +essentially it's a transition as you'll +see dramatized in um the film we're + + align:start position:0% +see dramatized in um the film we're + + + align:start position:0% +see dramatized in um the film we're +showing tonight um Grand delusion it's a + + align:start position:0% +showing tonight um Grand delusion it's a + + + align:start position:0% +showing tonight um Grand delusion it's a +it's a transition from an aristocratic + + align:start position:0% +it's a transition from an aristocratic + + + align:start position:0% +it's a transition from an aristocratic +to a middle class culture from from from + + align:start position:0% +to a middle class culture from from from + + + align:start position:0% +to a middle class culture from from from +a from from a from an aristocratic + + align:start position:0% +a from from a from an aristocratic + + + align:start position:0% +a from from a from an aristocratic +dispensation to a quasi Democratic or + + align:start position:0% +dispensation to a quasi Democratic or + + + align:start position:0% +dispensation to a quasi Democratic or +more democratic dispens ens ation uh and + + align:start position:0% +more democratic dispens ens ation uh and + + + align:start position:0% +more democratic dispens ens ation uh and +and uh this was a topic uh which which + + align:start position:0% +and uh this was a topic uh which which + + + align:start position:0% +and uh this was a topic uh which which +preoccupied many directors Renoir + + align:start position:0% +preoccupied many directors Renoir + + + align:start position:0% +preoccupied many directors Renoir +especially and is a kind of central + + align:start position:0% +especially and is a kind of central + + + align:start position:0% +especially and is a kind of central +Topic in both rules of the game and + + align:start position:0% +Topic in both rules of the game and + + + align:start position:0% +Topic in both rules of the game and +Grand Illusion this scene from uh rules + + align:start position:0% +Grand Illusion this scene from uh rules + + + align:start position:0% +Grand Illusion this scene from uh rules +of the game is maybe his least subtle in + + align:start position:0% +of the game is maybe his least subtle in + + + align:start position:0% +of the game is maybe his least subtle in +some ways or rather the subtlety is + + align:start position:0% +some ways or rather the subtlety is + + + align:start position:0% +some ways or rather the subtlety is +harder to see if you're just looking at + + align:start position:0% +harder to see if you're just looking at + + + align:start position:0% +harder to see if you're just looking at +a clip the subtlety in is involved in + + align:start position:0% +a clip the subtlety in is involved in + + + align:start position:0% +a clip the subtlety in is involved in +the characters themselves who have + + align:start position:0% +the characters themselves who have + + + align:start position:0% +the characters themselves who have +already in some degree been established + + align:start position:0% +already in some degree been established + + + align:start position:0% +already in some degree been established +in a kind of individ uality which then + + align:start position:0% +in a kind of individ uality which then + + + align:start position:0% +in a kind of individ uality which then +further expresses itself in the scene + + align:start position:0% +further expresses itself in the scene + + + align:start position:0% +further expresses itself in the scene +you're going to see uh the basic + + align:start position:0% +you're going to see uh the basic + + + align:start position:0% +you're going to see uh the basic +situation of uh uh the rules of the game + + align:start position:0% +situation of uh uh the rules of the game + + + align:start position:0% +situation of uh uh the rules of the game +is a is a classically uh uh powerful one + + align:start position:0% +is a is a classically uh uh powerful one + + + align:start position:0% +is a is a classically uh uh powerful one +uh uh + + align:start position:0% +uh uh + + + align:start position:0% +uh uh +it it's essentially a weekend of + + align:start position:0% +it it's essentially a weekend of + + + align:start position:0% +it it's essentially a weekend of +festivities a a marquee a grand figure + + align:start position:0% +festivities a a marquee a grand figure + + + align:start position:0% +festivities a a marquee a grand figure +at U presumably who owns a uh a + + align:start position:0% +at U presumably who owns a uh a + + + align:start position:0% +at U presumably who owns a uh a +remarkable Chateau invites a group many + + align:start position:0% +remarkable Chateau invites a group many + + + align:start position:0% +remarkable Chateau invites a group many +invites some friends for a weekend of + + align:start position:0% +invites some friends for a weekend of + + + align:start position:0% +invites some friends for a weekend of +games and shooting of hunting uh at his + + align:start position:0% +games and shooting of hunting uh at his + + + align:start position:0% +games and shooting of hunting uh at his +great Chateau in the country and uh uh + + align:start position:0% +great Chateau in the country and uh uh + + + align:start position:0% +great Chateau in the country and uh uh +the the the film is a kind of series of + + align:start position:0% +the the the film is a kind of series of + + + align:start position:0% +the the the film is a kind of series of +Tableau or a series of festivities all + + align:start position:0% +Tableau or a series of festivities all + + + align:start position:0% +Tableau or a series of festivities all +of which are cankered or damaged in some + + align:start position:0% +of which are cankered or damaged in some + + + align:start position:0% +of which are cankered or damaged in some +way it's as if we have a sense that each + + align:start position:0% +way it's as if we have a sense that each + + + align:start position:0% +way it's as if we have a sense that each +of the festivities or festivals that are + + align:start position:0% +of the festivities or festivals that are + + + align:start position:0% +of the festivities or festivals that are +dramatized in the rules of the game are + + align:start position:0% +dramatized in the rules of the game are + + + align:start position:0% +dramatized in the rules of the game are +diminished versions of something that in + + align:start position:0% +diminished versions of something that in + + + align:start position:0% +diminished versions of something that in +the past had great Authority power and + + align:start position:0% +the past had great Authority power and + + + align:start position:0% +the past had great Authority power and +cultural centrality but has but have + + align:start position:0% +cultural centrality but has but have + + + align:start position:0% +cultural centrality but has but have +become now diminished and even and even + + align:start position:0% +become now diminished and even and even + + + align:start position:0% +become now diminished and even and even +parodically uh uh reduced versions of + + align:start position:0% +parodically uh uh reduced versions of + + + align:start position:0% +parodically uh uh reduced versions of +what they had been when they were part + + align:start position:0% +what they had been when they were part + + + align:start position:0% +what they had been when they were part +of a coherent culture it's almost as if + + align:start position:0% +of a coherent culture it's almost as if + + + align:start position:0% +of a coherent culture it's almost as if +these festivals and rituals have become + + align:start position:0% +these festivals and rituals have become + + + align:start position:0% +these festivals and rituals have become +have been Rec are recognized by the film + + align:start position:0% +have been Rec are recognized by the film + + + align:start position:0% +have been Rec are recognized by the film +although not necessarily by the + + align:start position:0% +although not necessarily by the + + + align:start position:0% +although not necessarily by the +characters inside the film as vestiges + + align:start position:0% +characters inside the film as vestiges + + + align:start position:0% +characters inside the film as vestiges +of a time that has now passed and the + + align:start position:0% +of a time that has now passed and the + + + align:start position:0% +of a time that has now passed and the +most dramatic instance of this subject + + align:start position:0% +most dramatic instance of this subject + + + align:start position:0% +most dramatic instance of this subject +of the of the or embodiment of this + + align:start position:0% +of the of the or embodiment of this + + + align:start position:0% +of the of the or embodiment of this +theme is the senior going to see it's + + align:start position:0% +theme is the senior going to see it's + + + align:start position:0% +theme is the senior going to see it's +the hunting scene uh and uh I I I I I + + align:start position:0% +the hunting scene uh and uh I I I I I + + + align:start position:0% +the hunting scene uh and uh I I I I I +don't I I want you to sort of at least + + align:start position:0% +don't I I want you to sort of at least + + + align:start position:0% +don't I I want you to sort of at least +get a sense of it not not only because + + align:start position:0% +get a sense of it not not only because + + + align:start position:0% +get a sense of it not not only because +it's an important film and I'd like to + + align:start position:0% +it's an important film and I'd like to + + + align:start position:0% +it's an important film and I'd like to +fix it in your mind maybe give you a + + align:start position:0% +fix it in your mind maybe give you a + + + align:start position:0% +fix it in your mind maybe give you a +taste of it so you'll go out and look at + + align:start position:0% +taste of it so you'll go out and look at + + + align:start position:0% +taste of it so you'll go out and look at +the film yourself uh these two these two + + align:start position:0% +the film yourself uh these two these two + + + align:start position:0% +the film yourself uh these two these two +films Grand Illusion and and uh rules of + + align:start position:0% +films Grand Illusion and and uh rules of + + + align:start position:0% +films Grand Illusion and and uh rules of +the game are certainly the Pinnacle of + + align:start position:0% +the game are certainly the Pinnacle of + + + align:start position:0% +the game are certainly the Pinnacle of +renoir's Art and people who know these + + align:start position:0% +renoir's Art and people who know these + + + align:start position:0% +renoir's Art and people who know these +films deeply know something important + + align:start position:0% +films deeply know something important + + + align:start position:0% +films deeply know something important +about film know something important + + align:start position:0% +about film know something important + + + align:start position:0% +about film know something important +about what works of art are + + align:start position:0% +about what works of art are + + + align:start position:0% +about what works of art are +so I want you to see it for that reason + + align:start position:0% +so I want you to see it for that reason + + + align:start position:0% +so I want you to see it for that reason +but I also want you to see it to get one + + align:start position:0% +but I also want you to see it to get one + + + align:start position:0% +but I also want you to see it to get one +more experience outside of grand + + align:start position:0% +more experience outside of grand + + + align:start position:0% +more experience outside of grand +delusion of the way renoir's camera + + align:start position:0% +delusion of the way renoir's camera + + + align:start position:0% +delusion of the way renoir's camera +behaves and especially the way it + + align:start position:0% +behaves and especially the way it + + + align:start position:0% +behaves and especially the way it +establishes a relationship between + + align:start position:0% +establishes a relationship between + + + align:start position:0% +establishes a relationship between +character and and ground between + + align:start position:0% +character and and ground between + + + align:start position:0% +character and and ground between +character and environment and here of + + align:start position:0% +character and environment and here of + + + align:start position:0% +character and environment and here of +course the camera's job is not only to + + align:start position:0% +course the camera's job is not only to + + + align:start position:0% +course the camera's job is not only to +tell us something about the relations + + align:start position:0% +tell us something about the relations + + + align:start position:0% +tell us something about the relations +among the characters and to show us + + align:start position:0% +among the characters and to show us + + + align:start position:0% +among the characters and to show us +their interactions uh in in as + + align:start position:0% +their interactions uh in in as + + + align:start position:0% +their interactions uh in in as +economically powerful a way as possible + + align:start position:0% +economically powerful a way as possible + + + align:start position:0% +economically powerful a way as possible +but also to give us a sense of this of + + align:start position:0% +but also to give us a sense of this of + + + align:start position:0% +but also to give us a sense of this of +this Grand ritual gone bad + + align:start position:0% + + + + align:start position:0% + +okay all freeze it one second this the + + align:start position:0% +okay all freeze it one second this the + + + align:start position:0% +okay all freeze it one second this the +character who that little character + + align:start position:0% +character who that little character + + + align:start position:0% +character who that little character +who's giving instructions you will + + align:start position:0% +who's giving instructions you will + + + align:start position:0% +who's giving instructions you will +recognize him his the actor's name is + + align:start position:0% +recognize him his the actor's name is + + + align:start position:0% +recognize him his the actor's name is +Dalo and he's the one who plays rosenal + + align:start position:0% +Dalo and he's the one who plays rosenal + + + align:start position:0% +Dalo and he's the one who plays rosenal +in Grand Illusion in this film he plays + + align:start position:0% +in Grand Illusion in this film he plays + + + align:start position:0% +in Grand Illusion in this film he plays +the + + align:start position:0% + + + + align:start position:0% + +Marquee + + align:start position:0% + + + + align:start position:0% + +spe + + align:start position:0% + + + + align:start position:0% + +you see how powerful it is not to have + + align:start position:0% +you see how powerful it is not to have + + + align:start position:0% +you see how powerful it is not to have +fake + + align:start position:0% +fake + + + align:start position:0% +fake +music what just the effect of that is on + + align:start position:0% +music what just the effect of that is on + + + align:start position:0% +music what just the effect of that is on +the + + align:start position:0% + + + + align:start position:0% + +film I shouldn't say fake music non- + + align:start position:0% +film I shouldn't say fake music non- + + + align:start position:0% +film I shouldn't say fake music non- +diagetic music music That's not part of + + align:start position:0% +diagetic music music That's not part of + + + align:start position:0% +diagetic music music That's not part of +the scene + + align:start position:0% + + + + align:start position:0% + +itself there's + + align:start position:0% + + + + align:start position:0% + +Doo + + align:start position:0% + + + + align:start position:0% + +Ricky + + align:start position:0% + + + + align:start position:0% + +we + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% + + + + align:start position:0% + +freeze it for a second I wish we had + + align:start position:0% +freeze it for a second I wish we had + + + align:start position:0% +freeze it for a second I wish we had +time to dwell on this and I won't do + + align:start position:0% +time to dwell on this and I won't do + + + align:start position:0% +time to dwell on this and I won't do +this too much because I'll run out of + + align:start position:0% +this too much because I'll run out of + + + align:start position:0% +this too much because I'll run out of +time for what I need to tell you but + + align:start position:0% +time for what I need to tell you but + + + align:start position:0% +time for what I need to tell you but +tell me what you see here quickly make + + align:start position:0% +tell me what you see here quickly make + + + align:start position:0% +tell me what you see here quickly make +some conclusions about what what about + + align:start position:0% +some conclusions about what what about + + + align:start position:0% +some conclusions about what what about +this great ritual immediately what would + + align:start position:0% +this great ritual immediately what would + + + align:start position:0% +this great ritual immediately what would +we think if we watching if we're + + align:start position:0% +we think if we watching if we're + + + align:start position:0% +we think if we watching if we're +watching this what's one conclusion you + + align:start position:0% +watching this what's one conclusion you + + + align:start position:0% +watching this what's one conclusion you +draw from this + + align:start position:0% +draw from this + + + align:start position:0% +draw from this +is this uh is this is this hunting uh uh + + align:start position:0% +is this uh is this is this hunting uh uh + + + align:start position:0% +is this uh is this is this hunting uh uh +the the the activity of of of brave + + align:start position:0% +the the the activity of of of brave + + + align:start position:0% +the the the activity of of of brave +pionering souls who are confronting the + + align:start position:0% +pionering souls who are confronting the + + + align:start position:0% +pionering souls who are confronting the +dangers of the + + align:start position:0% +dangers of the + + + align:start position:0% +dangers of the +Wilderness right it's it's an + + align:start position:0% +Wilderness right it's it's an + + + align:start position:0% +Wilderness right it's it's an +unbelievably uh controlled and in many + + align:start position:0% +unbelievably uh controlled and in many + + + align:start position:0% +unbelievably uh controlled and in many +ways murderous environment isn't it what + + align:start position:0% +ways murderous environment isn't it what + + + align:start position:0% +ways murderous environment isn't it what +have we begun to feel about these about + + align:start position:0% +have we begun to feel about these about + + + align:start position:0% +have we begun to feel about these about +these creatures that are being flushed + + align:start position:0% +these creatures that are being flushed + + + align:start position:0% +these creatures that are being flushed +out tremendous sympathy for them right + + align:start position:0% +out tremendous sympathy for them right + + + align:start position:0% +out tremendous sympathy for them right +we're hostile to the adults right were + + align:start position:0% +we're hostile to the adults right were + + + align:start position:0% +we're hostile to the adults right were +hostile to the human beings in the scene + + align:start position:0% +hostile to the human beings in the scene + + + align:start position:0% +hostile to the human beings in the scene +we think there's something to matter + + align:start position:0% +we think there's something to matter + + + align:start position:0% +we think there's something to matter +with this and of course it's not in the + + align:start position:0% +with this and of course it's not in the + + + align:start position:0% +with this and of course it's not in the +olden days in the day in the presumably + + align:start position:0% +olden days in the day in the presumably + + + align:start position:0% +olden days in the day in the presumably +in the days when when such hunts + + align:start position:0% +in the days when when such hunts + + + align:start position:0% +in the days when when such hunts +occurred in a more in a more coherent + + align:start position:0% +occurred in a more in a more coherent + + + align:start position:0% +occurred in a more in a more coherent +and less and and less forced way you + + align:start position:0% +and less and and less forced way you + + + align:start position:0% +and less and and less forced way you +didn't need beaters to go around in the + + align:start position:0% +didn't need beaters to go around in the + + + align:start position:0% +didn't need beaters to go around in the +woods making noise to scare the few re + + align:start position:0% +woods making noise to scare the few re + + + align:start position:0% +woods making noise to scare the few re +the few vestiges of rabbits and other + + align:start position:0% +the few vestiges of rabbits and other + + + align:start position:0% +the few vestiges of rabbits and other +game out into the open so people with + + align:start position:0% +game out into the open so people with + + + align:start position:0% +game out into the open so people with +giant guns could kill them right because + + align:start position:0% +giant guns could kill them right because + + + align:start position:0% +giant guns could kill them right because +the place was teaming with in the 16th + + align:start position:0% +the place was teaming with in the 16th + + + align:start position:0% +the place was teaming with in the 16th +or the 15th century or the 18 Century + + align:start position:0% +or the 15th century or the 18 Century + + + align:start position:0% +or the 15th century or the 18 Century +the these fields were teaming with game + + align:start position:0% +the these fields were teaming with game + + + align:start position:0% +the these fields were teaming with game +now in the 20th century you have to beat + + align:start position:0% +now in the 20th century you have to beat + + + align:start position:0% +now in the 20th century you have to beat +the sticks to get them to come out what + + align:start position:0% +the sticks to get them to come out what + + + align:start position:0% +the sticks to get them to come out what +a parody of what an actual hunt would be + + align:start position:0% +a parody of what an actual hunt would be + + + align:start position:0% +a parody of what an actual hunt would be +go + + align:start position:0% + + + + align:start position:0% + +ahead when this film was made I forgot + + align:start position:0% +ahead when this film was made I forgot + + + align:start position:0% +ahead when this film was made I forgot +the number I have it in my notes but I + + align:start position:0% +the number I have it in my notes but I + + + align:start position:0% +the number I have it in my notes but I +couldn't find them there I left them in + + align:start position:0% +couldn't find them there I left them in + + + align:start position:0% +couldn't find them there I left them in +my office a a certain number of these + + align:start position:0% +my office a a certain number of these + + + align:start position:0% +my office a a certain number of these +animals were actually killed in the in + + align:start position:0% +animals were actually killed in the in + + + align:start position:0% +animals were actually killed in the in +the in the of the film I forgot the + + align:start position:0% +the in the of the film I forgot the + + + align:start position:0% +the in the of the film I forgot the +number but it's a significant + + align:start position:0% +number but it's a significant + + + align:start position:0% +number but it's a significant +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +number today they when they made such a + + align:start position:0% +number today they when they made such a + + + align:start position:0% +number today they when they made such a +film There are rules that don't allow + + align:start position:0% +film There are rules that don't allow + + + align:start position:0% +film There are rules that don't allow +them to kill + + align:start position:0% +them to kill + + + align:start position:0% +them to kill +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +[Applause] + + align:start position:0% + + + + align:start position:0% + +animals + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +[Music] + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +he + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% + + + + align:start position:0% + +okay you get some sense of how powerful + + align:start position:0% +okay you get some sense of how powerful + + + align:start position:0% +okay you get some sense of how powerful +a saturnist but also how quiet a + + align:start position:0% +a saturnist but also how quiet a + + + align:start position:0% +a saturnist but also how quiet a +saturnist he can be it's not as if the + + align:start position:0% +saturnist he can be it's not as if the + + + align:start position:0% +saturnist he can be it's not as if the +film it's not as if there's someone + + align:start position:0% +film it's not as if there's someone + + + align:start position:0% +film it's not as if there's someone +there saying isn't this horrible he's + + align:start position:0% +there saying isn't this horrible he's + + + align:start position:0% +there saying isn't this horrible he's +leaving it to the audience to figure out + + align:start position:0% +leaving it to the audience to figure out + + + align:start position:0% +leaving it to the audience to figure out +although it doesn't take too much to + + align:start position:0% +although it doesn't take too much to + + + align:start position:0% +although it doesn't take too much to +figure it out does it what what what you + + align:start position:0% +figure it out does it what what what you + + + align:start position:0% +figure it out does it what what what you +can't pick up from this it makes maybe + + align:start position:0% +can't pick up from this it makes maybe + + + align:start position:0% +can't pick up from this it makes maybe +the scene that I've shown you may make + + align:start position:0% +the scene that I've shown you may make + + + align:start position:0% +the scene that I've shown you may make +the scene seem cruder than it is + + align:start position:0% +the scene seem cruder than it is + + + align:start position:0% +the scene seem cruder than it is +virtually all the characters faces that + + align:start position:0% +virtually all the characters faces that + + + align:start position:0% +virtually all the characters faces that +you've seen many most of them anyway are + + align:start position:0% +you've seen many most of them anyway are + + + align:start position:0% +you've seen many most of them anyway are +major characters in the film and even by + + align:start position:0% +major characters in the film and even by + + + align:start position:0% +major characters in the film and even by +this time in the film you've gotten to + + align:start position:0% +this time in the film you've gotten to + + + align:start position:0% +this time in the film you've gotten to +know some of them quite well so they've + + align:start position:0% +know some of them quite well so they've + + + align:start position:0% +know some of them quite well so they've +been humanized and individual ated and + + align:start position:0% +been humanized and individual ated and + + + align:start position:0% +been humanized and individual ated and +that makes the brutality to which they + + align:start position:0% +that makes the brutality to which they + + + align:start position:0% +that makes the brutality to which they +are mostly oblivious of what's Happening + + align:start position:0% +are mostly oblivious of what's Happening + + + align:start position:0% +are mostly oblivious of what's Happening +even more powerful you don't hate the + + align:start position:0% +even more powerful you don't hate the + + + align:start position:0% +even more powerful you don't hate the +characters who are doing this shooting + + align:start position:0% +characters who are doing this shooting + + + align:start position:0% +characters who are doing this shooting +you know them for the comic and and + + align:start position:0% +you know them for the comic and and + + + align:start position:0% +you know them for the comic and and +damaged and ambitious and idealistic and + + align:start position:0% +damaged and ambitious and idealistic and + + + align:start position:0% +damaged and ambitious and idealistic and +and foolish characters they've already + + align:start position:0% +and foolish characters they've already + + + align:start position:0% +and foolish characters they've already +shown themselves to be by the time they + + align:start position:0% +shown themselves to be by the time they + + + align:start position:0% +shown themselves to be by the time they +get into this scene it's almost as if + + align:start position:0% +get into this scene it's almost as if + + + align:start position:0% +get into this scene it's almost as if +they themselves are also victims of this + + align:start position:0% +they themselves are also victims of this + + + align:start position:0% +they themselves are also victims of this +ritual they're part of so there's a kind + + align:start position:0% +ritual they're part of so there's a kind + + + align:start position:0% +ritual they're part of so there's a kind +of subtlety that you can't pick up on + + align:start position:0% +of subtlety that you can't pick up on + + + align:start position:0% +of subtlety that you can't pick up on +just watching the clip that that uh is + + align:start position:0% +just watching the clip that that uh is + + + align:start position:0% +just watching the clip that that uh is +present for any for any audience member + + align:start position:0% +present for any for any audience member + + + align:start position:0% +present for any for any audience member +but I wanted you to see the this scene + + align:start position:0% +but I wanted you to see the this scene + + + align:start position:0% +but I wanted you to see the this scene +also in part again to show you how + + align:start position:0% +also in part again to show you how + + + align:start position:0% +also in part again to show you how +powerfully uh Ren War's camera is able + + align:start position:0% +powerfully uh Ren War's camera is able + + + align:start position:0% +powerfully uh Ren War's camera is able +to uh create emotional and intellectual + + align:start position:0% +to uh create emotional and intellectual + + + align:start position:0% +to uh create emotional and intellectual +responses in the audience in a way that + + align:start position:0% +responses in the audience in a way that + + + align:start position:0% +responses in the audience in a way that +is in some sense diametrically opposed + + align:start position:0% +is in some sense diametrically opposed + + + align:start position:0% +is in some sense diametrically opposed +to what we might call expressionist + + align:start position:0% +to what we might call expressionist + + + align:start position:0% +to what we might call expressionist +directors like Hitchcock or eisenstein + + align:start position:0% +directors like Hitchcock or eisenstein + + + align:start position:0% +directors like Hitchcock or eisenstein +might do by manipulating our our our + + align:start position:0% +might do by manipulating our our our + + + align:start position:0% +might do by manipulating our our our +attitudes by uh constant by very rapid + + align:start position:0% +attitudes by uh constant by very rapid + + + align:start position:0% +attitudes by uh constant by very rapid +edit and and by giving us high or low + + align:start position:0% +edit and and by giving us high or low + + + align:start position:0% +edit and and by giving us high or low +angle shots that control our emotional + + align:start position:0% +angle shots that control our emotional + + + align:start position:0% +angle shots that control our emotional +response because of the way we're seeing + + align:start position:0% +response because of the way we're seeing + + + align:start position:0% +response because of the way we're seeing +things uh uh renoir's strategies can be + + align:start position:0% +things uh uh renoir's strategies can be + + + align:start position:0% +things uh uh renoir's strategies can be +just as powerful in terms of emotional + + align:start position:0% +just as powerful in terms of emotional + + + align:start position:0% +just as powerful in terms of emotional +and moral reaction but Renoir Renoir + + align:start position:0% +and moral reaction but Renoir Renoir + + + align:start position:0% +and moral reaction but Renoir Renoir +strategy is quite different present the + + align:start position:0% +strategy is quite different present the + + + align:start position:0% +strategy is quite different present the +evidence in some sense to the to the + + align:start position:0% +evidence in some sense to the to the + + + align:start position:0% +evidence in some sense to the to the +audience keep keep the keep the camera + + align:start position:0% +audience keep keep the keep the camera + + + align:start position:0% +audience keep keep the keep the camera +at at a level that allows the full + + align:start position:0% +at at a level that allows the full + + + align:start position:0% +at at a level that allows the full +action to be taken in I I hope you + + align:start position:0% +action to be taken in I I hope you + + + align:start position:0% +action to be taken in I I hope you +realize that there were relatively few + + align:start position:0% +realize that there were relatively few + + + align:start position:0% +realize that there were relatively few +Cuts in that scene and in in most of uh + + align:start position:0% +Cuts in that scene and in in most of uh + + + align:start position:0% +Cuts in that scene and in in most of uh +renoir's work the number of edits is + + align:start position:0% +renoir's work the number of edits is + + + align:start position:0% +renoir's work the number of edits is +relatively small compared to the number + + align:start position:0% +relatively small compared to the number + + + align:start position:0% +relatively small compared to the number +of scenes that are extended the number + + align:start position:0% +of scenes that are extended the number + + + align:start position:0% +of scenes that are extended the number +the the the long the amount of long + + align:start position:0% +the the the long the amount of long + + + align:start position:0% +the the the long the amount of long +takes that we have and there are certain + + align:start position:0% +takes that we have and there are certain + + + align:start position:0% +takes that we have and there are certain +moments in the in the film where he will + + align:start position:0% +moments in the in the film where he will + + + align:start position:0% +moments in the in the film where he will +vary this strategy for example and you + + align:start position:0% +vary this strategy for example and you + + + align:start position:0% +vary this strategy for example and you +might want to watch for this in + + align:start position:0% +might want to watch for this in + + + align:start position:0% +might want to watch for this in +tonight's film there's one moment in + + align:start position:0% +tonight's film there's one moment in + + + align:start position:0% +tonight's film there's one moment in +tonight's film + + align:start position:0% +tonight's film + + + align:start position:0% +tonight's film +uh where uh an interview between two of + + align:start position:0% +uh where uh an interview between two of + + + align:start position:0% +uh where uh an interview between two of +the central characters the the German + + align:start position:0% +the central characters the the German + + + align:start position:0% +the central characters the the German +prison Warden uh + + align:start position:0% +prison Warden uh + + + align:start position:0% +prison Warden uh +played by Eric Von scheim uh and the the + + align:start position:0% +played by Eric Von scheim uh and the the + + + align:start position:0% +played by Eric Von scheim uh and the the +the French Aristocrat um named dubu + + align:start position:0% +the French Aristocrat um named dubu + + + align:start position:0% +the French Aristocrat um named dubu +played by an actor named defres defr and + + align:start position:0% +played by an actor named defres defr and + + + align:start position:0% +played by an actor named defres defr and +and U uh in this scene between the + + align:start position:0% +and U uh in this scene between the + + + align:start position:0% +and U uh in this scene between the +German and the Frenchman one of the + + align:start position:0% +German and the Frenchman one of the + + + align:start position:0% +German and the Frenchman one of the +things we recognize is because they + + align:start position:0% +things we recognize is because they + + + align:start position:0% +things we recognize is because they +belong to the aristocratic class they + + align:start position:0% +belong to the aristocratic class they + + + align:start position:0% +belong to the aristocratic class they +have a lot in common what they speak + + align:start position:0% +have a lot in common what they speak + + + align:start position:0% +have a lot in common what they speak +English for example they because they + + align:start position:0% +English for example they because they + + + align:start position:0% +English for example they because they +both know English right even though + + align:start position:0% +both know English right even though + + + align:start position:0% +both know English right even though +one's a German and one's a Frenchman and + + align:start position:0% +one's a German and one's a Frenchman and + + + align:start position:0% +one's a German and one's a Frenchman and +there is a sense in the film of a very + + align:start position:0% +there is a sense in the film of a very + + + align:start position:0% +there is a sense in the film of a very +powerful one that's established that + + align:start position:0% +powerful one that's established that + + + align:start position:0% +powerful one that's established that +they have in in some sense a greater + + align:start position:0% +they have in in some sense a greater + + + align:start position:0% +they have in in some sense a greater +connection to each other than they have + + align:start position:0% +connection to each other than they have + + + align:start position:0% +connection to each other than they have +with their own uh uh uh with other + + align:start position:0% +with their own uh uh uh with other + + + align:start position:0% +with their own uh uh uh with other +soldiers of of in in their own armies uh + + align:start position:0% +soldiers of of in in their own armies uh + + + align:start position:0% +soldiers of of in in their own armies uh +and the film is the film meditates on + + align:start position:0% +and the film is the film meditates on + + + align:start position:0% +and the film is the film meditates on +these distinctions and especially on + + align:start position:0% +these distinctions and especially on + + + align:start position:0% +these distinctions and especially on +this uh conundrum of social class in + + align:start position:0% +this uh conundrum of social class in + + + align:start position:0% +this uh conundrum of social class in +rather a complex way as as I'll suggest + + align:start position:0% +rather a complex way as as I'll suggest + + + align:start position:0% +rather a complex way as as I'll suggest +well in the very first scene between um + + align:start position:0% +well in the very first scene between um + + + align:start position:0% +well in the very first scene between um +uh uh Balu and ralen Stein the German + + align:start position:0% +uh uh Balu and ralen Stein the German + + + align:start position:0% +uh uh Balu and ralen Stein the German +and the Frenchmen um um + + align:start position:0% +and the Frenchmen um um + + + align:start position:0% +and the Frenchmen um um +Renoir uses a fairly standard procedure + + align:start position:0% +Renoir uses a fairly standard procedure + + + align:start position:0% +Renoir uses a fairly standard procedure +much more common to other directors it's + + align:start position:0% +much more common to other directors it's + + + align:start position:0% +much more common to other directors it's +sometimes called a shot counter shot + + align:start position:0% +sometimes called a shot counter shot + + + align:start position:0% +sometimes called a shot counter shot +style so that when you're it's + + align:start position:0% +style so that when you're it's + + + align:start position:0% +style so that when you're it's +especially common on American television + + align:start position:0% +especially common on American television + + + align:start position:0% +especially common on American television +but it was it's common in the movies too + + align:start position:0% +but it was it's common in the movies too + + + align:start position:0% +but it was it's common in the movies too +in which when you see characters in + + align:start position:0% +in which when you see characters in + + + align:start position:0% +in which when you see characters in +conversation uh you'll get relatively + + align:start position:0% +conversation uh you'll get relatively + + + align:start position:0% +conversation uh you'll get relatively +rapid cutting and you look at one face + + align:start position:0% +rapid cutting and you look at one face + + + align:start position:0% +rapid cutting and you look at one face +then then the camera will shift and you + + align:start position:0% +then then the camera will shift and you + + + align:start position:0% +then then the camera will shift and you +look back at the other face there'll be + + align:start position:0% +look back at the other face there'll be + + + align:start position:0% +look back at the other face there'll be +a cut and you'll look at right and you + + align:start position:0% +a cut and you'll look at right and you + + + align:start position:0% +a cut and you'll look at right and you +you'll constantly shift back and forth + + align:start position:0% +you'll constantly shift back and forth + + + align:start position:0% +you'll constantly shift back and forth +this shot counter shot style uh but he + + align:start position:0% +this shot counter shot style uh but he + + + align:start position:0% +this shot counter shot style uh but he +renir uses this kind of style rarely + + align:start position:0% +renir uses this kind of style rarely + + + align:start position:0% +renir uses this kind of style rarely +because it involves the first of all it + + align:start position:0% +because it involves the first of all it + + + align:start position:0% +because it involves the first of all it +involves the idea of cutting it involves + + align:start position:0% +involves the idea of cutting it involves + + + align:start position:0% +involves the idea of cutting it involves +the idea of separation why use shot + + align:start position:0% +the idea of separation why use shot + + + align:start position:0% +the idea of separation why use shot +counter shot Renoir would say when I can + + align:start position:0% +counter shot Renoir would say when I can + + + align:start position:0% +counter shot Renoir would say when I can +move my camera like this and show the + + align:start position:0% +move my camera like this and show the + + + align:start position:0% +move my camera like this and show the +two characters together and move it and + + align:start position:0% +two characters together and move it and + + + align:start position:0% +two characters together and move it and +move it around in another way and show + + align:start position:0% +move it around in another way and show + + + align:start position:0% +move it around in another way and show +the back of one character's head and the + + align:start position:0% +the back of one character's head and the + + + align:start position:0% +the back of one character's head and the +way the other is re in other words if + + align:start position:0% +way the other is re in other words if + + + align:start position:0% +way the other is re in other words if +the camera if the camera's part of the + + align:start position:0% +the camera if the camera's part of the + + + align:start position:0% +the camera if the camera's part of the +action a fluid part of the action + + align:start position:0% +action a fluid part of the action + + + align:start position:0% +action a fluid part of the action +there's more I can show you more about + + align:start position:0% +there's more I can show you more about + + + align:start position:0% +there's more I can show you more about +character renmore would say but in that + + align:start position:0% +character renmore would say but in that + + + align:start position:0% +character renmore would say but in that +particular scene he doesn't do it in + + align:start position:0% +particular scene he doesn't do it in + + + align:start position:0% +particular scene he doesn't do it in +this first interview extended interview + + align:start position:0% +this first interview extended interview + + + align:start position:0% +this first interview extended interview +it lasts about 2 minutes and 45 seconds + + align:start position:0% +it lasts about 2 minutes and 45 seconds + + + align:start position:0% +it lasts about 2 minutes and 45 seconds +and it uses 21 shots 21 separate shots + + align:start position:0% +and it uses 21 shots 21 separate shots + + + align:start position:0% +and it uses 21 shots 21 separate shots +in 2 minutes and 45 seconds for Renoir + + align:start position:0% +in 2 minutes and 45 seconds for Renoir + + + align:start position:0% +in 2 minutes and 45 seconds for Renoir +that's a tremendous number of edits + + align:start position:0% +that's a tremendous number of edits + + + align:start position:0% +that's a tremendous number of edits +right and one way you can tell that this + + align:start position:0% +right and one way you can tell that this + + + align:start position:0% +right and one way you can tell that this +is a and what what why would he do it + + align:start position:0% +is a and what what why would he do it + + + align:start position:0% +is a and what what why would he do it +there because it's very unusual for him + + align:start position:0% +there because it's very unusual for him + + + align:start position:0% +there because it's very unusual for him +to use this shot counter shot style in + + align:start position:0% +to use this shot counter shot style in + + + align:start position:0% +to use this shot counter shot style in +the film why would he do it he wants to + + align:start position:0% +the film why would he do it he wants to + + + align:start position:0% +the film why would he do it he wants to +emphasize their separation their + + align:start position:0% +emphasize their separation their + + + align:start position:0% +emphasize their separation their +isolation from each other their distance + + align:start position:0% +isolation from each other their distance + + + align:start position:0% +isolation from each other their distance +from each other right and and there is a + + align:start position:0% +from each other right and and there is a + + + align:start position:0% +from each other right and and there is a +later scene in the film uh near the very + + align:start position:0% +later scene in the film uh near the very + + + align:start position:0% +later scene in the film uh near the very +end the film uh again between du and uh + + align:start position:0% +end the film uh again between du and uh + + + align:start position:0% +end the film uh again between du and uh +uh uh uh uh and another character uh but + + align:start position:0% +uh uh uh uh and another character uh but + + + align:start position:0% +uh uh uh uh and another character uh but +this one between du and marel the French + + align:start position:0% +this one between du and marel the French + + + align:start position:0% +this one between du and marel the French +working man who working class figure + + align:start position:0% +working man who working class figure + + + align:start position:0% +working man who working class figure +who's who's on the French side just + + align:start position:0% +who's who's on the French side just + + + align:start position:0% +who's who's on the French side just +before there's an attempted escape and + + align:start position:0% +before there's an attempted escape and + + + align:start position:0% +before there's an attempted escape and +that scene is almost as long it's 2 + + align:start position:0% +that scene is almost as long it's 2 + + + align:start position:0% +that scene is almost as long it's 2 +minutes and and 20 seconds long but that + + align:start position:0% +minutes and and 20 seconds long but that + + + align:start position:0% +minutes and and 20 seconds long but that +scene only has three separate edits in + + align:start position:0% +scene only has three separate edits in + + + align:start position:0% +scene only has three separate edits in +it and you might compare it the farewell + + align:start position:0% +it and you might compare it the farewell + + + align:start position:0% +it and you might compare it the farewell +scene is a very obvious one and you'll + + align:start position:0% +scene is a very obvious one and you'll + + + align:start position:0% +scene is a very obvious one and you'll +you'll recognize it when you see it and + + align:start position:0% +you'll recognize it when you see it and + + + align:start position:0% +you'll recognize it when you see it and +and and of course the reason is that he + + align:start position:0% +and and of course the reason is that he + + + align:start position:0% +and and of course the reason is that he +wants to emphasize in so far as it's + + align:start position:0% +wants to emphasize in so far as it's + + + align:start position:0% +wants to emphasize in so far as it's +possible that they are together he wants + + align:start position:0% +possible that they are together he wants + + + align:start position:0% +possible that they are together he wants +to minimize the sense of isolation uh in + + align:start position:0% +to minimize the sense of isolation uh in + + + align:start position:0% +to minimize the sense of isolation uh in +that sequence again I mention this + + align:start position:0% +that sequence again I mention this + + + align:start position:0% +that sequence again I mention this +because I want you to become as + + align:start position:0% +because I want you to become as + + + align:start position:0% +because I want you to become as +attentive as possible without destroying + + align:start position:0% +attentive as possible without destroying + + + align:start position:0% +attentive as possible without destroying +your enjoyment of the film to the + + align:start position:0% +your enjoyment of the film to the + + + align:start position:0% +your enjoyment of the film to the +camera's way of Behaving uh so U one of + + align:start position:0% +camera's way of Behaving uh so U one of + + + align:start position:0% +camera's way of Behaving uh so U one of +the ways to summarize what I'm trying to + + align:start position:0% +the ways to summarize what I'm trying to + + + align:start position:0% +the ways to summarize what I'm trying to +say about the way the camera Works in + + align:start position:0% +say about the way the camera Works in + + + align:start position:0% +say about the way the camera Works in +Renoir I want to remind you that even in + + align:start position:0% +Renoir I want to remind you that even in + + + align:start position:0% +Renoir I want to remind you that even in +his darkest films uh um the his his + + align:start position:0% +his darkest films uh um the his his + + + align:start position:0% +his darkest films uh um the his his +camera work carries an undercurrent of + + align:start position:0% +camera work carries an undercurrent of + + + align:start position:0% +camera work carries an undercurrent of +excitement even sometimes a kind of Joy + + align:start position:0% +excitement even sometimes a kind of Joy + + + align:start position:0% +excitement even sometimes a kind of Joy +at the sheer particular the + + align:start position:0% +at the sheer particular the + + + align:start position:0% +at the sheer particular the +particularity of the world um uh you can + + align:start position:0% +particularity of the world um uh you can + + + align:start position:0% +particularity of the world um uh you can +you can sense his his awareness of + + align:start position:0% +you can sense his his awareness of + + + align:start position:0% +you can sense his his awareness of +ambigu of human ambiguity and his Wonder + + align:start position:0% +ambigu of human ambiguity and his Wonder + + + align:start position:0% +ambigu of human ambiguity and his Wonder +at the texture of the visible world uh + + align:start position:0% +at the texture of the visible world uh + + + align:start position:0% +at the texture of the visible world uh +all through his films of the French of + + align:start position:0% +all through his films of the French of + + + align:start position:0% +all through his films of the French of +his of his so-called French period and + + align:start position:0% +his of his so-called French period and + + + align:start position:0% +his of his so-called French period and +especially in the film you're going to + + align:start position:0% +especially in the film you're going to + + + align:start position:0% +especially in the film you're going to +see tonight which is in many ways in + + align:start position:0% +see tonight which is in many ways in + + + align:start position:0% +see tonight which is in many ways in +environments that are very un poetic + + align:start position:0% +environments that are very un poetic + + + align:start position:0% +environments that are very un poetic +right there the entire film takes place + + align:start position:0% +right there the entire film takes place + + + align:start position:0% +right there the entire film takes place +in a series of prison camps the entire + + align:start position:0% +in a series of prison camps the entire + + + align:start position:0% +in a series of prison camps the entire +film is about these French prisoners of + + align:start position:0% +film is about these French prisoners of + + + align:start position:0% +film is about these French prisoners of +War there's an introduction or prologue + + align:start position:0% +War there's an introduction or prologue + + + align:start position:0% +War there's an introduction or prologue +before they're captured and then after + + align:start position:0% +before they're captured and then after + + + align:start position:0% +before they're captured and then after +they're captured we see them in a series + + align:start position:0% +they're captured we see them in a series + + + align:start position:0% +they're captured we see them in a series +of prison camps uh um and and uh uh it's + + align:start position:0% +of prison camps uh um and and uh uh it's + + + align:start position:0% +of prison camps uh um and and uh uh it's +quite an + + align:start position:0% +quite an + + + align:start position:0% +quite an +amazing experience in some ways to watch + + align:start position:0% +amazing experience in some ways to watch + + + align:start position:0% +amazing experience in some ways to watch +renoir's camera discover the complexity + + align:start position:0% +renoir's camera discover the complexity + + + align:start position:0% +renoir's camera discover the complexity +of even the uh of of of of a of of of a + + align:start position:0% +of even the uh of of of of a of of of a + + + align:start position:0% +of even the uh of of of of a of of of a +of a world that seems in on the surface + + align:start position:0% +of a world that seems in on the surface + + + align:start position:0% +of a world that seems in on the surface +to be so un promising uh and so + + align:start position:0% +to be so un promising uh and so + + + align:start position:0% +to be so un promising uh and so +uninteresting so lacking in texture uh + + align:start position:0% +uninteresting so lacking in texture uh + + + align:start position:0% +uninteresting so lacking in texture uh +we we can think of U we can think of + + align:start position:0% +we we can think of U we can think of + + + align:start position:0% +we we can think of U we can think of +renoir's camera as shy timid in a sense + + align:start position:0% +renoir's camera as shy timid in a sense + + + align:start position:0% +renoir's camera as shy timid in a sense +capable of embarrassment even there's + + align:start position:0% +capable of embarrassment even there's + + + align:start position:0% +capable of embarrassment even there's +one moment in the rules of the game + + align:start position:0% +one moment in the rules of the game + + + align:start position:0% +one moment in the rules of the game +which partly involves a a kind of it has + + align:start position:0% +which partly involves a a kind of it has + + + align:start position:0% +which partly involves a a kind of it has +a farce Dimension so that they when the + + align:start position:0% +a farce Dimension so that they when the + + + align:start position:0% +a farce Dimension so that they when the +when all the guests in the in the great + + align:start position:0% +when all the guests in the in the great + + + align:start position:0% +when all the guests in the in the great +state the in the great um uh estate or + + align:start position:0% +state the in the great um uh estate or + + + align:start position:0% +state the in the great um uh estate or +Castle uh go to sleep at night they + + align:start position:0% +Castle uh go to sleep at night they + + + align:start position:0% +Castle uh go to sleep at night they +there there's a they sort of come out of + + align:start position:0% +there there's a they sort of come out of + + + align:start position:0% +there there's a they sort of come out of +their rooms and start you know changing + + align:start position:0% +their rooms and start you know changing + + + align:start position:0% +their rooms and start you know changing +bed partners and things like that they + + align:start position:0% +bed partners and things like that they + + + align:start position:0% +bed partners and things like that they +they have various liaison and there's a + + align:start position:0% +they have various liaison and there's a + + + align:start position:0% +they have various liaison and there's a +moment when the camera is in the this + + align:start position:0% +moment when the camera is in the this + + + align:start position:0% +moment when the camera is in the this +long hallway and one of the lovers comes + + align:start position:0% +long hallway and one of the lovers comes + + + align:start position:0% +long hallway and one of the lovers comes +out to meet another lover and the C it + + align:start position:0% +out to meet another lover and the C it + + + align:start position:0% +out to meet another lover and the C it +looks as if the camera actually backs + + align:start position:0% +looks as if the camera actually backs + + + align:start position:0% +looks as if the camera actually backs +away in embarrassment and looks away as + + align:start position:0% +away in embarrassment and looks away as + + + align:start position:0% +away in embarrassment and looks away as +if it says oh that's inappropriate for + + align:start position:0% +if it says oh that's inappropriate for + + + align:start position:0% +if it says oh that's inappropriate for +me to be looking at so there's the + + align:start position:0% +me to be looking at so there's the + + + align:start position:0% +me to be looking at so there's the +camera is humanized in a very uh uh + + align:start position:0% +camera is humanized in a very uh uh + + + align:start position:0% +camera is humanized in a very uh uh +subtle quiet way all the way through + + align:start position:0% +subtle quiet way all the way through + + + align:start position:0% +subtle quiet way all the way through +renoir's uh uh work uh so we can think + + align:start position:0% +renoir's uh uh work uh so we can think + + + align:start position:0% +renoir's uh uh work uh so we can think +of his camera as shy as embarrassed + + align:start position:0% +of his camera as shy as embarrassed + + + align:start position:0% +of his camera as shy as embarrassed +reluctant to overhear or to intrude um + + align:start position:0% +reluctant to overhear or to intrude um + + + align:start position:0% +reluctant to overhear or to intrude um +there are even moments when it is + + align:start position:0% +there are even moments when it is + + + align:start position:0% +there are even moments when it is +distracted or drawn to an apparently + + align:start position:0% +distracted or drawn to an apparently + + + align:start position:0% +distracted or drawn to an apparently +irrelevant element uh times when the + + align:start position:0% +irrelevant element uh times when the + + + align:start position:0% +irrelevant element uh times when the +camera hesitates or even appears to + + align:start position:0% +camera hesitates or even appears to + + + align:start position:0% +camera hesitates or even appears to +change its mind an uncertain camera then + + align:start position:0% +change its mind an uncertain camera then + + + align:start position:0% +change its mind an uncertain camera then +always adjusting to a world that is + + align:start position:0% +always adjusting to a world that is + + + align:start position:0% +always adjusting to a world that is +itself always shifting and changing and + + align:start position:0% +itself always shifting and changing and + + + align:start position:0% +itself always shifting and changing and +of course that's the deepest argument + + align:start position:0% +of course that's the deepest argument + + + align:start position:0% +of course that's the deepest argument +for why this the camera is so Restless + + align:start position:0% +for why this the camera is so Restless + + + align:start position:0% +for why this the camera is so Restless +remember it's not obtrusive it's not + + align:start position:0% +remember it's not obtrusive it's not + + + align:start position:0% +remember it's not obtrusive it's not +like you feel the camera swinging wildly + + align:start position:0% +like you feel the camera swinging wildly + + + align:start position:0% +like you feel the camera swinging wildly +not at all you have to pay attention + + align:start position:0% +not at all you have to pay attention + + + align:start position:0% +not at all you have to pay attention +sometime you won't even be aware of the + + align:start position:0% +sometime you won't even be aware of the + + + align:start position:0% +sometime you won't even be aware of the +fact of how quietly and subtly the + + align:start position:0% +fact of how quietly and subtly the + + + align:start position:0% +fact of how quietly and subtly the +camera but it's as if the camera is + + align:start position:0% +camera but it's as if the camera is + + + align:start position:0% +camera but it's as if the camera is +always making adjustments as if it's + + align:start position:0% +always making adjustments as if it's + + + align:start position:0% +always making adjustments as if it's +always alive to the changing character + + align:start position:0% +always alive to the changing character + + + align:start position:0% +always alive to the changing character +of what it's looking at and that very + + align:start position:0% +of what it's looking at and that very + + + align:start position:0% +of what it's looking at and that very +aliveness reminds you of how complex + + align:start position:0% +aliveness reminds you of how complex + + + align:start position:0% +aliveness reminds you of how complex +reality is because reality itself is + + align:start position:0% +reality is because reality itself is + + + align:start position:0% +reality is because reality itself is +always shifting and changing um + + align:start position:0% + + + + align:start position:0% + +um this describes I think something of + + align:start position:0% +um this describes I think something of + + + align:start position:0% +um this describes I think something of +what is meant by renoir's realism but + + align:start position:0% +what is meant by renoir's realism but + + + align:start position:0% +what is meant by renoir's realism but +there's a kind of lyric element as I've + + align:start position:0% +there's a kind of lyric element as I've + + + align:start position:0% +there's a kind of lyric element as I've +mentioned a kind of even a kind of + + align:start position:0% +mentioned a kind of even a kind of + + + align:start position:0% +mentioned a kind of even a kind of +Tranquility or pleasure or Joy + + align:start position:0% +Tranquility or pleasure or Joy + + + align:start position:0% +Tranquility or pleasure or Joy +celebratory impulse in his camera's gaze + + align:start position:0% +celebratory impulse in his camera's gaze + + + align:start position:0% +celebratory impulse in his camera's gaze +that qualifies or sweetens his realism + + align:start position:0% +that qualifies or sweetens his realism + + + align:start position:0% +that qualifies or sweetens his realism +of space and character and we need to be + + align:start position:0% +of space and character and we need to be + + + align:start position:0% +of space and character and we need to be +aware of that too one way to crystallize + + align:start position:0% +aware of that too one way to crystallize + + + align:start position:0% +aware of that too one way to crystallize +this is to suggest that once we become + + align:start position:0% +this is to suggest that once we become + + + align:start position:0% +this is to suggest that once we become +attuned to the camera's forms of + + align:start position:0% +attuned to the camera's forms of + + + align:start position:0% +attuned to the camera's forms of +attention that's a good phrase the + + align:start position:0% +attention that's a good phrase the + + + align:start position:0% +attention that's a good phrase the +camera's forms of attention uh there a + + align:start position:0% +camera's forms of attention uh there a + + + align:start position:0% +camera's forms of attention uh there a +wonderful book about poetry called forms + + align:start position:0% +wonderful book about poetry called forms + + + align:start position:0% +wonderful book about poetry called forms +of attention right lyric poetry is + + align:start position:0% +of attention right lyric poetry is + + + align:start position:0% +of attention right lyric poetry is +constit it's a special kind of attention + + align:start position:0% +constit it's a special kind of attention + + + align:start position:0% +constit it's a special kind of attention +we can say that that renoir's + + align:start position:0% +we can say that that renoir's + + + align:start position:0% +we can say that that renoir's +camera is is engaged constantly in these + + align:start position:0% +camera is is engaged constantly in these + + + align:start position:0% +camera is is engaged constantly in these +forms of attention um um once we become + + align:start position:0% +forms of attention um um once we become + + + align:start position:0% +forms of attention um um once we become +aware of that of that of the camera's + + align:start position:0% +aware of that of that of the camera's + + + align:start position:0% +aware of that of that of the camera's +interest in that uh we become aware of a + + align:start position:0% +interest in that uh we become aware of a + + + align:start position:0% +interest in that uh we become aware of a +quiet continuous struggle a loving + + align:start position:0% +quiet continuous struggle a loving + + + align:start position:0% +quiet continuous struggle a loving +contest almost between the multiple + + align:start position:0% +contest almost between the multiple + + + align:start position:0% +contest almost between the multiple +points of interest in the scene and the + + align:start position:0% +points of interest in the scene and the + + + align:start position:0% +points of interest in the scene and the +camera's reluctant gently hesitant + + align:start position:0% +camera's reluctant gently hesitant + + + align:start position:0% +camera's reluctant gently hesitant +choices the menu of things to see and + + align:start position:0% +choices the menu of things to see and + + + align:start position:0% +choices the menu of things to see and +hear R Wars films keep telling + + align:start position:0% +hear R Wars films keep telling + + + align:start position:0% +hear R Wars films keep telling +us is too rich to be fully captured even + + align:start position:0% +us is too rich to be fully captured even + + + align:start position:0% +us is too rich to be fully captured even +by the most generous eye and that's what + + align:start position:0% +by the most generous eye and that's what + + + align:start position:0% +by the most generous eye and that's what +I mean when I say that visual style can + + align:start position:0% +I mean when I say that visual style can + + + align:start position:0% +I mean when I say that visual style can +be understood as a form of moral style + + align:start position:0% +be understood as a form of moral style + + + align:start position:0% +be understood as a form of moral style +right uh I want to say a few more words + + align:start position:0% +right uh I want to say a few more words + + + align:start position:0% +right uh I want to say a few more words +about uh Grand delusion itself to help + + align:start position:0% +about uh Grand delusion itself to help + + + align:start position:0% +about uh Grand delusion itself to help +frame your uh experience of it uh it's + + align:start position:0% +frame your uh experience of it uh it's + + + align:start position:0% +frame your uh experience of it uh it's +not a complex film but it's a deep and + + align:start position:0% +not a complex film but it's a deep and + + + align:start position:0% +not a complex film but it's a deep and +beautiful one and I think you'll all + + align:start position:0% +beautiful one and I think you'll all + + + align:start position:0% +beautiful one and I think you'll all +find it very memorable first a word + + align:start position:0% +find it very memorable first a word + + + align:start position:0% +find it very memorable first a word +about the actors um or or maybe I should + + align:start position:0% +about the actors um or or maybe I should + + + align:start position:0% +about the actors um or or maybe I should +say one other word about about Renoir + + align:start position:0% +say one other word about about Renoir + + + align:start position:0% +say one other word about about Renoir +himself because it Bears on his actors + + align:start position:0% +himself because it Bears on his actors + + + align:start position:0% +himself because it Bears on his actors +as I implied or I think suggested this + + align:start position:0% +as I implied or I think suggested this + + + align:start position:0% +as I implied or I think suggested this +afternoon one of the most distinctive + + align:start position:0% +afternoon one of the most distinctive + + + align:start position:0% +afternoon one of the most distinctive +features of renoir's practice and follow + + align:start position:0% +features of renoir's practice and follow + + + align:start position:0% +features of renoir's practice and follow +if you think about the way his camera + + align:start position:0% +if you think about the way his camera + + + align:start position:0% +if you think about the way his camera +behaves you can see how logically + + align:start position:0% +behaves you can see how logically + + + align:start position:0% +behaves you can see how logically +connected these elements are was that he + + align:start position:0% +connected these elements are was that he + + + align:start position:0% +connected these elements are was that he +was an improvisational director he + + align:start position:0% +was an improvisational director he + + + align:start position:0% +was an improvisational director he +collaborated with his actors with his + + align:start position:0% +collaborated with his actors with his + + + align:start position:0% +collaborated with his actors with his +performers he didn't come in with an + + align:start position:0% +performers he didn't come in with an + + + align:start position:0% +performers he didn't come in with an +absolutely fixed script he's he's like + + align:start position:0% +absolutely fixed script he's he's like + + + align:start position:0% +absolutely fixed script he's he's like +the anti- Hitchcock + + align:start position:0% +the anti- Hitchcock + + + align:start position:0% +the anti- Hitchcock +Hitchcock has solved all his problems + + align:start position:0% +Hitchcock has solved all his problems + + + align:start position:0% +Hitchcock has solved all his problems +before he's come in to do his shooting + + align:start position:0% +before he's come in to do his shooting + + + align:start position:0% +before he's come in to do his shooting +Renoir has just begun the process of + + align:start position:0% +Renoir has just begun the process of + + + align:start position:0% +Renoir has just begun the process of +making his movie when he he has an idea + + align:start position:0% +making his movie when he he has an idea + + + align:start position:0% +making his movie when he he has an idea +of his subject matter he knows what he's + + align:start position:0% +of his subject matter he knows what he's + + + align:start position:0% +of his subject matter he knows what he's +doing he knows he I don't mean that he's + + align:start position:0% +doing he knows he I don't mean that he's + + + align:start position:0% +doing he knows he I don't mean that he's +working completely blind but he + + align:start position:0% +working completely blind but he + + + align:start position:0% +working completely blind but he +allows Discovery to take place in the + + align:start position:0% +allows Discovery to take place in the + + + align:start position:0% +allows Discovery to take place in the +course of the making of the movies of + + align:start position:0% +course of the making of the movies of + + + align:start position:0% +course of the making of the movies of +his movies and he's very deeply involved + + align:start position:0% +his movies and he's very deeply involved + + + align:start position:0% +his movies and he's very deeply involved +in collaborating with his performers so + + align:start position:0% +in collaborating with his performers so + + + align:start position:0% +in collaborating with his performers so +that for example um when he had already + + align:start position:0% +that for example um when he had already + + + align:start position:0% +that for example um when he had already +begun working on the movie I I don't + + align:start position:0% +begun working on the movie I I don't + + + align:start position:0% +begun working on the movie I I don't +think they they hadn't beun I don't + + align:start position:0% +think they they hadn't beun I don't + + + align:start position:0% +think they they hadn't beun I don't +think they'd begun shooting it yet but + + align:start position:0% +think they'd begun shooting it yet but + + + align:start position:0% +think they'd begun shooting it yet but +they were very far along in creating the + + align:start position:0% +they were very far along in creating the + + + align:start position:0% +they were very far along in creating the +movie and in casting the movie when they + + align:start position:0% +movie and in casting the movie when they + + + align:start position:0% +movie and in casting the movie when they +discovered that Eric Von stroheim who + + align:start position:0% +discovered that Eric Von stroheim who + + + align:start position:0% +discovered that Eric Von stroheim who +was all already by then by the time this + + align:start position:0% +was all already by then by the time this + + + align:start position:0% +was all already by then by the time this +film was made a very well-known actor + + align:start position:0% +film was made a very well-known actor + + + align:start position:0% +film was made a very well-known actor +and director much in fact incredibly + + align:start position:0% +and director much in fact incredibly + + + align:start position:0% +and director much in fact incredibly +admired director uh both both an actor + + align:start position:0% +admired director uh both both an actor + + + align:start position:0% +admired director uh both both an actor +and a director uh uh agreed to join the + + align:start position:0% +and a director uh uh agreed to join the + + + align:start position:0% +and a director uh uh agreed to join the +film and when he agreed to join the film + + align:start position:0% +film and when he agreed to join the film + + + align:start position:0% +film and when he agreed to join the film +he and Renoir began to collaborate on + + align:start position:0% +he and Renoir began to collaborate on + + + align:start position:0% +he and Renoir began to collaborate on +expanding the role that on scheim plays + + align:start position:0% +expanding the role that on scheim plays + + + align:start position:0% +expanding the role that on scheim plays +and you'll understand what an what what + + align:start position:0% +and you'll understand what an what what + + + align:start position:0% +and you'll understand what an what what +an immensely helpful contribution to the + + align:start position:0% +an immensely helpful contribution to the + + + align:start position:0% +an immensely helpful contribution to the +what what could we call it to the + + align:start position:0% +what what could we call it to the + + + align:start position:0% +what what could we call it to the +Ecology of the movie to the sense of the + + align:start position:0% +Ecology of the movie to the sense of the + + + align:start position:0% +Ecology of the movie to the sense of the +movie uh uh Von stroheim May because his + + align:start position:0% +movie uh uh Von stroheim May because his + + + align:start position:0% +movie uh uh Von stroheim May because his +because he's one of the dominant + + align:start position:0% +because he's one of the dominant + + + align:start position:0% +because he's one of the dominant +characters his his if if we if we if we + + align:start position:0% +characters his his if if we if we if we + + + align:start position:0% +characters his his if if we if we if we +try to imagine Grand Illusion with a + + align:start position:0% +try to imagine Grand Illusion with a + + + align:start position:0% +try to imagine Grand Illusion with a +much reduced role for the Von stroheim + + align:start position:0% +much reduced role for the Von stroheim + + + align:start position:0% +much reduced role for the Von stroheim +character it's a much lesser film you + + align:start position:0% +character it's a much lesser film you + + + align:start position:0% +character it's a much lesser film you +could so you can recognize what an and + + align:start position:0% +could so you can recognize what an and + + + align:start position:0% +could so you can recognize what an and +uh what an extraordinary contribution V + + align:start position:0% +uh what an extraordinary contribution V + + + align:start position:0% +uh what an extraordinary contribution V +strohi made now he not only made + + align:start position:0% +strohi made now he not only made + + + align:start position:0% +strohi made now he not only made +contributions to questions about the + + align:start position:0% +contributions to questions about the + + + align:start position:0% +contributions to questions about the +dialogue what the character would say + + align:start position:0% +dialogue what the character would say + + + align:start position:0% +dialogue what the character would say +expanded the role but even made + + align:start position:0% +expanded the role but even made + + + align:start position:0% +expanded the role but even made +suggestions about how the character + + align:start position:0% +suggestions about how the character + + + align:start position:0% +suggestions about how the character +would look what what what uh cut how the + + align:start position:0% +would look what what what uh cut how the + + + align:start position:0% +would look what what what uh cut how the +character would be customed and I think + + align:start position:0% +character would be customed and I think + + + align:start position:0% +character would be customed and I think +it was Von stroheim who emphasi who who + + align:start position:0% +it was Von stroheim who emphasi who who + + + align:start position:0% +it was Von stroheim who emphasi who who +who emphasized even more fully than + + align:start position:0% +who emphasized even more fully than + + + align:start position:0% +who emphasized even more fully than +Renoir had originally intended that the + + align:start position:0% +Renoir had originally intended that the + + + align:start position:0% +Renoir had originally intended that the +Von stroheim character is a war Casualty + + align:start position:0% +Von stroheim character is a war Casualty + + + align:start position:0% +Von stroheim character is a war Casualty +that he has a ram rod up his back that + + align:start position:0% +that he has a ram rod up his back that + + + align:start position:0% +that he has a ram rod up his back that +he can he has to wear gloves because his + + align:start position:0% +he can he has to wear gloves because his + + + align:start position:0% +he can he has to wear gloves because his +hands are horribly burned he's a + + align:start position:0% +hands are horribly burned he's a + + + align:start position:0% +hands are horribly burned he's a +and that's why he's now running prison + + align:start position:0% +and that's why he's now running prison + + + align:start position:0% +and that's why he's now running prison +camps because he's not useful for + + align:start position:0% +camps because he's not useful for + + + align:start position:0% +camps because he's not useful for +anything else right and there's the + + align:start position:0% +anything else right and there's the + + + align:start position:0% +anything else right and there's the +sense that he's a damaged U uh uh um + + align:start position:0% +sense that he's a damaged U uh uh um + + + align:start position:0% +sense that he's a damaged U uh uh um +wounded figure even from the very + + align:start position:0% +wounded figure even from the very + + + align:start position:0% +wounded figure even from the very +beginning of the film when we when we + + align:start position:0% +beginning of the film when we when we + + + align:start position:0% +beginning of the film when we when we +first meet him uh but one of so that's + + align:start position:0% +first meet him uh but one of so that's + + + align:start position:0% +first meet him uh but one of so that's +important in itself but there's a second + + align:start position:0% +important in itself but there's a second + + + align:start position:0% +important in itself but there's a second +thing about F stran that I want to + + align:start position:0% +thing about F stran that I want to + + + align:start position:0% +thing about F stran that I want to +emphasize to you to it shows you how uh + + align:start position:0% +emphasize to you to it shows you how uh + + + align:start position:0% +emphasize to you to it shows you how uh +subtly Renoir was aware of how he could + + align:start position:0% +subtly Renoir was aware of how he could + + + align:start position:0% +subtly Renoir was aware of how he could +utilize all the elements available to + + align:start position:0% +utilize all the elements available to + + + align:start position:0% +utilize all the elements available to +him as a filmmaker Von stroheim was + + align:start position:0% +him as a filmmaker Von stroheim was + + + align:start position:0% +him as a filmmaker Von stroheim was +especially well known as an actor for + + align:start position:0% +especially well known as an actor for + + + align:start position:0% +especially well known as an actor for +roles in which he would play this was + + align:start position:0% +roles in which he would play this was + + + align:start position:0% +roles in which he would play this was +especially true in roles he played in + + align:start position:0% +especially true in roles he played in + + + align:start position:0% +especially true in roles he played in +the United States in which he would play + + align:start position:0% +the United States in which he would play + + + align:start position:0% +the United States in which he would play +a dangerous scary martinet a kind of a + + align:start position:0% +a dangerous scary martinet a kind of a + + + align:start position:0% +a dangerous scary martinet a kind of a +kind of uh there there were even hints + + align:start position:0% +kind of uh there there were even hints + + + align:start position:0% +kind of uh there there were even hints +of s masochism about the role sometime + + align:start position:0% +of s masochism about the role sometime + + + align:start position:0% +of s masochism about the role sometime +so he would play he would play uh uh + + align:start position:0% +so he would play he would play uh uh + + + align:start position:0% +so he would play he would play uh uh +brutal brutal prison camp wardens right + + align:start position:0% +brutal brutal prison camp wardens right + + + align:start position:0% +brutal brutal prison camp wardens right +or brutal police types brutal BR + + align:start position:0% +or brutal police types brutal BR + + + align:start position:0% +or brutal police types brutal BR +militarist types right uh violent + + align:start position:0% +militarist types right uh violent + + + align:start position:0% +militarist types right uh violent +husbands right uh he became and and in + + align:start position:0% +husbands right uh he became and and in + + + align:start position:0% +husbands right uh he became and and in +fact he he was understood also as a + + align:start position:0% +fact he he was understood also as a + + + align:start position:0% +fact he he was understood also as a +villain he often played roles that were + + align:start position:0% +villain he often played roles that were + + + align:start position:0% +villain he often played roles that were +recognizably evil roles he came to be + + align:start position:0% +recognizably evil roles he came to be + + + align:start position:0% +recognizably evil roles he came to be +known as the man you love to hate that + + align:start position:0% +known as the man you love to hate that + + + align:start position:0% +known as the man you love to hate that +was like his sort of it was a sort of + + align:start position:0% +was like his sort of it was a sort of + + + align:start position:0% +was like his sort of it was a sort of +motto that was attached to his to his + + align:start position:0% +motto that was attached to his to his + + + align:start position:0% +motto that was attached to his to his +name and when you watch Grand Illusion + + align:start position:0% +name and when you watch Grand Illusion + + + align:start position:0% +name and when you watch Grand Illusion +one of the things I hope you'll think + + align:start position:0% +one of the things I hope you'll think + + + align:start position:0% +one of the things I hope you'll think +about is the comple the complex way in + + align:start position:0% +about is the comple the complex way in + + + align:start position:0% +about is the comple the complex way in +which that inherited idea of the Von + + align:start position:0% +which that inherited idea of the Von + + + align:start position:0% +which that inherited idea of the Von +stroheim character is complicated + + align:start position:0% +stroheim character is complicated + + + align:start position:0% +stroheim character is complicated +undermined and humanized because in many + + align:start position:0% +undermined and humanized because in many + + + align:start position:0% +undermined and humanized because in many +ways he still is the villain in the + + align:start position:0% +ways he still is the villain in the + + + align:start position:0% +ways he still is the villain in the +piece but he's a humanized villain he's + + align:start position:0% +piece but he's a humanized villain he's + + + align:start position:0% +piece but he's a humanized villain he's +a he becomes a complex character as much + + align:start position:0% +a he becomes a complex character as much + + + align:start position:0% +a he becomes a complex character as much +a victim of what's Happening happening + + align:start position:0% +a victim of what's Happening happening + + + align:start position:0% +a victim of what's Happening happening +of his as much a victim of history as + + align:start position:0% +of his as much a victim of history as + + + align:start position:0% +of his as much a victim of history as +any of the other characters in the film + + align:start position:0% +any of the other characters in the film + + + align:start position:0% +any of the other characters in the film +so uh there's a sense in which this in + + align:start position:0% +so uh there's a sense in which this in + + + align:start position:0% +so uh there's a sense in which this in +which what what Renoir and Von stroheim + + align:start position:0% +which what what Renoir and Von stroheim + + + align:start position:0% +which what what Renoir and Von stroheim +together are doing is taking the Persona + + align:start position:0% +together are doing is taking the Persona + + + align:start position:0% +together are doing is taking the Persona +that Von stroheim had established and + + align:start position:0% +that Von stroheim had established and + + + align:start position:0% +that Von stroheim had established and +undercutting it undermining it in some + + align:start position:0% +undercutting it undermining it in some + + + align:start position:0% +undercutting it undermining it in some +in some slight way creating a much + + align:start position:0% +in some slight way creating a much + + + align:start position:0% +in some slight way creating a much +greater resonance for the character + + align:start position:0% +greater resonance for the character + + + align:start position:0% +greater resonance for the character +exactly because of the ways in which he + + align:start position:0% +exactly because of the ways in which he + + + align:start position:0% +exactly because of the ways in which he +first that appears to fulfill the + + align:start position:0% +first that appears to fulfill the + + + align:start position:0% +first that appears to fulfill the +expectations that he's an evil villain + + align:start position:0% +expectations that he's an evil villain + + + align:start position:0% +expectations that he's an evil villain +and then as the film goes on this sense + + align:start position:0% +and then as the film goes on this sense + + + align:start position:0% +and then as the film goes on this sense +is undermined complicated and you + + align:start position:0% +is undermined complicated and you + + + align:start position:0% +is undermined complicated and you +realize that he's a he's a human being + + align:start position:0% +realize that he's a he's a human being + + + align:start position:0% +realize that he's a he's a human being +with W with with with powers of + + align:start position:0% +with W with with with powers of + + + align:start position:0% +with W with with with powers of +generosity although also certain + + align:start position:0% +generosity although also certain + + + align:start position:0% +generosity although also certain +limitations uh he's pre he's a German + + align:start position:0% +limitations uh he's pre he's a German + + + align:start position:0% +limitations uh he's pre he's a German +he's a Prejudice he has he doesn't + + align:start position:0% +he's a Prejudice he has he doesn't + + + align:start position:0% +he's a Prejudice he has he doesn't +really like the French especially + + align:start position:0% +really like the French especially + + + align:start position:0% +really like the French especially +doesn't like workingclass people most + + align:start position:0% +doesn't like workingclass people most + + + align:start position:0% +doesn't like workingclass people most +especially doesn't like Jews right I + + align:start position:0% +especially doesn't like Jews right I + + + align:start position:0% +especially doesn't like Jews right I +mean it's not he's an imperfect + + align:start position:0% +mean it's not he's an imperfect + + + align:start position:0% +mean it's not he's an imperfect +character but you see that he's deeply + + align:start position:0% +character but you see that he's deeply + + + align:start position:0% +character but you see that he's deeply +humanized and something of the same kind + + align:start position:0% +humanized and something of the same kind + + + align:start position:0% +humanized and something of the same kind +of thing happens in the film's treatment + + align:start position:0% +of thing happens in the film's treatment + + + align:start position:0% +of thing happens in the film's treatment +of the Jeong gabang character the the + + align:start position:0% +of the Jeong gabang character the the + + + align:start position:0% +of the Jeong gabang character the the +really he he's the character who plays + + align:start position:0% +really he he's the character who plays + + + align:start position:0% +really he he's the character who plays +marishal the actor who plays marishal + + align:start position:0% +marishal the actor who plays marishal + + + align:start position:0% +marishal the actor who plays marishal +the workingclass um um Frenchman who + + align:start position:0% +the workingclass um um Frenchman who + + + align:start position:0% +the workingclass um um Frenchman who +along with du and and uh the uh the Jew + + align:start position:0% +along with du and and uh the uh the Jew + + + align:start position:0% +along with du and and uh the uh the Jew +played by the Jew played by + + align:start position:0% +played by the Jew played by + + + align:start position:0% +played by the Jew played by +Dalo character called rosental these + + align:start position:0% +Dalo character called rosental these + + + align:start position:0% +Dalo character called rosental these +three are the central uh French + + align:start position:0% +three are the central uh French + + + align:start position:0% +three are the central uh French +characters and we see them moving from + + align:start position:0% +characters and we see them moving from + + + align:start position:0% +characters and we see them moving from +prison camp to prison camp through the + + align:start position:0% +prison camp to prison camp through the + + + align:start position:0% +prison camp to prison camp through the +film that that group is the central uh + + align:start position:0% +film that that group is the central uh + + + align:start position:0% +film that that group is the central uh +group of the film and we follow them as + + align:start position:0% +group of the film and we follow them as + + + align:start position:0% +group of the film and we follow them as +the film goes on uh the gabang character + + align:start position:0% +the film goes on uh the gabang character + + + align:start position:0% +the film goes on uh the gabang character +too was the in many ways the most famous + + align:start position:0% +too was the in many ways the most famous + + + align:start position:0% +too was the in many ways the most famous +actor of of if not in Europe certainly + + align:start position:0% +actor of of if not in Europe certainly + + + align:start position:0% +actor of of if not in Europe certainly +in France of the late 20s and 30s major + + align:start position:0% +in France of the late 20s and 30s major + + + align:start position:0% +in France of the late 20s and 30s major +major figure uh and he he was especially + + align:start position:0% +major figure uh and he he was especially + + + align:start position:0% +major figure uh and he he was especially +associated with workingclass roles and + + align:start position:0% +associated with workingclass roles and + + + align:start position:0% +associated with workingclass roles and +most especially associated with roles he + + align:start position:0% +most especially associated with roles he + + + align:start position:0% +most especially associated with roles he +was like an early Jack Nicholson an even + + align:start position:0% +was like an early Jack Nicholson an even + + + align:start position:0% +was like an early Jack Nicholson an even +more powerful version of it because he + + align:start position:0% +more powerful version of it because he + + + align:start position:0% +more powerful version of it because he +became famous for these moments in the + + align:start position:0% +became famous for these moments in the + + + align:start position:0% +became famous for these moments in the +films when he would go nuts when he + + align:start position:0% +films when he would go nuts when he + + + align:start position:0% +films when he would go nuts when he +would have a fit when he would start + + align:start position:0% +would have a fit when he would start + + + align:start position:0% +would have a fit when he would start +screaming or he would lose it right he + + align:start position:0% +screaming or he would lose it right he + + + align:start position:0% +screaming or he would lose it right he +would he would rant or Rave or and and + + align:start position:0% +would he would rant or Rave or and and + + + align:start position:0% +would he would rant or Rave or and and +in some of the films in some films he + + align:start position:0% +in some of the films in some films he + + + align:start position:0% +in some of the films in some films he +was in he would have a a climactic scene + + align:start position:0% +was in he would have a a climactic scene + + + align:start position:0% +was in he would have a a climactic scene +this may be in fact where the uh uh + + align:start position:0% +this may be in fact where the uh uh + + + align:start position:0% +this may be in fact where the uh uh +stereotype began he would have a + + align:start position:0% +stereotype began he would have a + + + align:start position:0% +stereotype began he would have a +climactic scene often he was like he + + align:start position:0% +climactic scene often he was like he + + + align:start position:0% +climactic scene often he was like he +would be a suicidal proletarian right a + + align:start position:0% +would be a suicidal proletarian right a + + + align:start position:0% +would be a suicidal proletarian right a +suicidal worker up against the forces of + + align:start position:0% +suicidal worker up against the forces of + + + align:start position:0% +suicidal worker up against the forces of +capitalism or the forces of the police + + align:start position:0% +capitalism or the forces of the police + + + align:start position:0% +capitalism or the forces of the police +right the gabang character had frequent + + align:start position:0% +right the gabang character had frequent + + + align:start position:0% +right the gabang character had frequent +roles like this uh in which he would in + + align:start position:0% +roles like this uh in which he would in + + + align:start position:0% +roles like this uh in which he would in +which he would U uh essentially Lo lose + + align:start position:0% +which he would U uh essentially Lo lose + + + align:start position:0% +which he would U uh essentially Lo lose +all rational control and rant and Rave + + align:start position:0% +all rational control and rant and Rave + + + align:start position:0% +all rational control and rant and Rave +and scream sometimes die right uh and he + + align:start position:0% +and scream sometimes die right uh and he + + + align:start position:0% +and scream sometimes die right uh and he +he was so famous for this and this was + + align:start position:0% +he was so famous for this and this was + + + align:start position:0% +he was so famous for this and this was +such a fundamental part of his Persona + + align:start position:0% +such a fundamental part of his Persona + + + align:start position:0% +such a fundamental part of his Persona +that he uh had written into most of his + + align:start position:0% +that he uh had written into most of his + + + align:start position:0% +that he uh had written into most of his +contracts that he had to have a scene in + + align:start position:0% +contracts that he had to have a scene in + + + align:start position:0% +contracts that he had to have a scene in +which he did this he had to have at + + align:start position:0% +which he did this he had to have at + + + align:start position:0% +which he did this he had to have at +least one scene in the film in which he + + align:start position:0% +least one scene in the film in which he + + + align:start position:0% +least one scene in the film in which he +sort of went kukamonga in which he in + + align:start position:0% +sort of went kukamonga in which he in + + + align:start position:0% +sort of went kukamonga in which he in +which he lost it right now one of the + + align:start position:0% +which he lost it right now one of the + + + align:start position:0% +which he lost it right now one of the +most subtle things about this film is + + align:start position:0% +most subtle things about this film is + + + align:start position:0% +most subtle things about this film is +there is such a moment in this film + + align:start position:0% +there is such a moment in this film + + + align:start position:0% +there is such a moment in this film +watch for youan because it's so quiet + + align:start position:0% +watch for youan because it's so quiet + + + align:start position:0% +watch for youan because it's so quiet +compared to what you might expect that + + align:start position:0% +compared to what you might expect that + + + align:start position:0% +compared to what you might expect that +you might miss it but it's really there + + align:start position:0% +you might miss it but it's really there + + + align:start position:0% +you might miss it but it's really there +and in fact the way in which it both + + align:start position:0% +and in fact the way in which it both + + + align:start position:0% +and in fact the way in which it both +fulfills but also undermines our + + align:start position:0% +fulfills but also undermines our + + + align:start position:0% +fulfills but also undermines our +expectations about this character again + + align:start position:0% +expectations about this character again + + + align:start position:0% +expectations about this character again +tells us something about the way in + + align:start position:0% +tells us something about the way in + + + align:start position:0% +tells us something about the way in +which Renoir and his collaborating + + align:start position:0% +which Renoir and his collaborating + + + align:start position:0% +which Renoir and his collaborating +actors were able to create immensely + + align:start position:0% +actors were able to create immensely + + + align:start position:0% +actors were able to create immensely +nuanced meanings uh possibilities out of + + align:start position:0% +nuanced meanings uh possibilities out of + + + align:start position:0% +nuanced meanings uh possibilities out of +the raw material of their of not only of + + align:start position:0% +the raw material of their of not only of + + + align:start position:0% +the raw material of their of not only of +the story of the film and of the setting + + align:start position:0% +the story of the film and of the setting + + + align:start position:0% +the story of the film and of the setting +of the film but even the past history of + + align:start position:0% +of the film but even the past history of + + + align:start position:0% +of the film but even the past history of +the + + align:start position:0% +the + + + align:start position:0% +the +performers I want to say just a couple + + align:start position:0% +performers I want to say just a couple + + + align:start position:0% +performers I want to say just a couple +of things about some of the dominant um + + align:start position:0% +of things about some of the dominant um + + + align:start position:0% +of things about some of the dominant um +uh themes in the film to help uh + + align:start position:0% +uh themes in the film to help uh + + + align:start position:0% +uh themes in the film to help uh +organize your experience of it and I'm + + align:start position:0% +organize your experience of it and I'm + + + align:start position:0% +organize your experience of it and I'm +borrowing here or deeply influenced here + + align:start position:0% +borrowing here or deeply influenced here + + + align:start position:0% +borrowing here or deeply influenced here +by two critics especially although I + + align:start position:0% +by two critics especially although I + + + align:start position:0% +by two critics especially although I +mean I I perhaps I should say + + align:start position:0% +mean I I perhaps I should say + + + align:start position:0% +mean I I perhaps I should say +parenthetically uh you should probably + + align:start position:0% +parenthetically uh you should probably + + + align:start position:0% +parenthetically uh you should probably +uh uh assume that almost anything I say + + align:start position:0% +uh uh assume that almost anything I say + + + align:start position:0% +uh uh assume that almost anything I say +has been said by someone else somewhere + + align:start position:0% +has been said by someone else somewhere + + + align:start position:0% +has been said by someone else somewhere +some at some time in the past and words + + align:start position:0% +some at some time in the past and words + + + align:start position:0% +some at some time in the past and words +the job of a teacher as I conceive it is + + align:start position:0% +the job of a teacher as I conceive it is + + + align:start position:0% +the job of a teacher as I conceive it is +not to come up with totally original + + align:start position:0% +not to come up with totally original + + + align:start position:0% +not to come up with totally original +arguments every time because no one can + + align:start position:0% +arguments every time because no one can + + + align:start position:0% +arguments every time because no one can +be so original as to say everything + + align:start position:0% +be so original as to say everything + + + align:start position:0% +be so original as to say everything +that's wonderful about particular text + + align:start position:0% +that's wonderful about particular text + + + align:start position:0% +that's wonderful about particular text +or about a whole phenomenon like the + + align:start position:0% +or about a whole phenomenon like the + + + align:start position:0% +or about a whole phenomenon like the +movies right so a good teacher draws on + + align:start position:0% +movies right so a good teacher draws on + + + align:start position:0% +movies right so a good teacher draws on +that and I I when I really am drawing on + + align:start position:0% +that and I I when I really am drawing on + + + align:start position:0% +that and I I when I really am drawing on +a on a prior scholar who I know has uh + + align:start position:0% +a on a prior scholar who I know has uh + + + align:start position:0% +a on a prior scholar who I know has uh +shaped the arguments I'm making or has + + align:start position:0% +shaped the arguments I'm making or has + + + align:start position:0% +shaped the arguments I'm making or has +given me the the categories I'm using I + + align:start position:0% +given me the the categories I'm using I + + + align:start position:0% +given me the the categories I'm using I +mention them by name but of course I've + + align:start position:0% +mention them by name but of course I've + + + align:start position:0% +mention them by name but of course I've +been teaching for so long that much of + + align:start position:0% +been teaching for so long that much of + + + align:start position:0% +been teaching for so long that much of +this must now be uh U and unconsciously + + align:start position:0% +this must now be uh U and unconsciously + + + align:start position:0% +this must now be uh U and unconsciously +absorbed into my into my psyche and I + + align:start position:0% +absorbed into my into my psyche and I + + + align:start position:0% +absorbed into my into my psyche and I +don't always know this so I I'm not + + align:start position:0% +don't always know this so I I'm not + + + align:start position:0% +don't always know this so I I'm not +saying that those moments where I + + align:start position:0% +saying that those moments where I + + + align:start position:0% +saying that those moments where I +haven't made this acknowledgement are + + align:start position:0% +haven't made this acknowledgement are + + + align:start position:0% +haven't made this acknowledgement are +free of such influence quite the + + align:start position:0% +free of such influence quite the + + + align:start position:0% +free of such influence quite the +opposite but I do want to mention two + + align:start position:0% +opposite but I do want to mention two + + + align:start position:0% +opposite but I do want to mention two +Scholars who have especially influenced + + align:start position:0% +Scholars who have especially influenced + + + align:start position:0% +Scholars who have especially influenced +me on on uh Renoir uh because virtually + + align:start position:0% +me on on uh Renoir uh because virtually + + + align:start position:0% +me on on uh Renoir uh because virtually +all the things I've told you about + + align:start position:0% +all the things I've told you about + + + align:start position:0% +all the things I've told you about +Renoir although I've made the ideas my + + align:start position:0% +Renoir although I've made the ideas my + + + align:start position:0% +Renoir although I've made the ideas my +own come from these one is a a Frenchman + + align:start position:0% +own come from these one is a a Frenchman + + + align:start position:0% +own come from these one is a a Frenchman +named Alexander + + align:start position:0% +named Alexander + + + align:start position:0% +named Alexander +sansi uh and wrote a wonderful book on + + align:start position:0% +sansi uh and wrote a wonderful book on + + + align:start position:0% +sansi uh and wrote a wonderful book on +on I think it's several volume book on + + align:start position:0% +on I think it's several volume book on + + + align:start position:0% +on I think it's several volume book on +on Renoir that taught me a tremendous + + align:start position:0% +on Renoir that taught me a tremendous + + + align:start position:0% +on Renoir that taught me a tremendous +amount of especially about his French uh + + align:start position:0% +amount of especially about his French uh + + + align:start position:0% +amount of especially about his French uh +period and the other is the is the uh uh + + align:start position:0% +period and the other is the is the uh uh + + + align:start position:0% +period and the other is the is the uh uh +California scholar now California + + align:start position:0% +California scholar now California + + + align:start position:0% +California scholar now California +scholar Leo Brody one of whose essays + + align:start position:0% +scholar Leo Brody one of whose essays + + + align:start position:0% +scholar Leo Brody one of whose essays +I've asked you to read in this course + + align:start position:0% +I've asked you to read in this course + + + align:start position:0% +I've asked you to read in this course +and he's written a wonderful book on + + align:start position:0% +and he's written a wonderful book on + + + align:start position:0% +and he's written a wonderful book on +Renoir uh and uh although I have read + + align:start position:0% +Renoir uh and uh although I have read + + + align:start position:0% +Renoir uh and uh although I have read +the book I learned more about Renoir + + align:start position:0% +the book I learned more about Renoir + + + align:start position:0% +the book I learned more about Renoir +from Brody in conversation because he + + align:start position:0% +from Brody in conversation because he + + + align:start position:0% +from Brody in conversation because he +was my colleague many years ago when we + + align:start position:0% +was my colleague many years ago when we + + + align:start position:0% +was my colleague many years ago when we +were teaching together in the English + + align:start position:0% +were teaching together in the English + + + align:start position:0% +were teaching together in the English +Department at Yale and he's one of the + + align:start position:0% +Department at Yale and he's one of the + + + align:start position:0% +Department at Yale and he's one of the +people who turned me into a person + + align:start position:0% +people who turned me into a person + + + align:start position:0% +people who turned me into a person +interested in movies interested in film + + align:start position:0% +interested in movies interested in film + + + align:start position:0% +interested in movies interested in film +so Leo Brody b r a u d y Alexander sansi + + align:start position:0% +so Leo Brody b r a u d y Alexander sansi + + + align:start position:0% +so Leo Brody b r a u d y Alexander sansi +s s o n + + align:start position:0% +s s o n + + + align:start position:0% +s s o n +ke the two + + align:start position:0% +ke the two + + + align:start position:0% +ke the two +principal Scholars and critics behind + + align:start position:0% +principal Scholars and critics behind + + + align:start position:0% +principal Scholars and critics behind +what I've been saying both this + + align:start position:0% +what I've been saying both this + + + align:start position:0% +what I've been saying both this +afternoon and this + + align:start position:0% +afternoon and this + + + align:start position:0% +afternoon and this +evening dominant themes one the prison + + align:start position:0% +evening dominant themes one the prison + + + align:start position:0% +evening dominant themes one the prison +camp as a microcosm right uh there's a + + align:start position:0% +camp as a microcosm right uh there's a + + + align:start position:0% +camp as a microcosm right uh there's a +wonderful passage at one point in the in + + align:start position:0% +wonderful passage at one point in the in + + + align:start position:0% +wonderful passage at one point in the in +the movie where one of the characters + + align:start position:0% +the movie where one of the characters + + + align:start position:0% +the movie where one of the characters +said everyone would die of the disease + + align:start position:0% +said everyone would die of the disease + + + align:start position:0% +said everyone would die of the disease +of his class if the war did not + + align:start position:0% +of his class if the war did not + + + align:start position:0% +of his class if the war did not +reconcile all + + align:start position:0% +reconcile all + + + align:start position:0% +reconcile all +microbes and think about the + + align:start position:0% +microbes and think about the + + + align:start position:0% +microbes and think about the +implications of that words the idea is + + align:start position:0% +implications of that words the idea is + + + align:start position:0% +implications of that words the idea is +that what the what one of the things + + align:start position:0% +that what the what one of the things + + + align:start position:0% +that what the what one of the things +that makes this prison camp such a + + align:start position:0% +that makes this prison camp such a + + + align:start position:0% +that makes this prison camp such a +fascinating place is that it is in some + + align:start position:0% +fascinating place is that it is in some + + + align:start position:0% +fascinating place is that it is in some +sense a microcosm of the larger + + align:start position:0% +sense a microcosm of the larger + + + align:start position:0% +sense a microcosm of the larger +world and and in especially if you if + + align:start position:0% +world and and in especially if you if + + + align:start position:0% +world and and in especially if you if +you think of the prison camp Beyond just + + align:start position:0% +you think of the prison camp Beyond just + + + align:start position:0% +you think of the prison camp Beyond just +the the the uh grouping of the French + + align:start position:0% +the the the uh grouping of the French + + + align:start position:0% +the the the uh grouping of the French +soldiers whom the French prisoners whom + + align:start position:0% +soldiers whom the French prisoners whom + + + align:start position:0% +soldiers whom the French prisoners whom +we follow primarily what you can + + align:start position:0% +we follow primarily what you can + + + align:start position:0% +we follow primarily what you can +recognize this you back away because we + + align:start position:0% +recognize this you back away because we + + + align:start position:0% +recognize this you back away because we +we are told about and we meet and we see + + align:start position:0% +we are told about and we meet and we see + + + align:start position:0% +we are told about and we meet and we see +briefly some of the other prisoners + + align:start position:0% +briefly some of the other prisoners + + + align:start position:0% +briefly some of the other prisoners +there are there are Russian prisoners + + align:start position:0% +there are there are Russian prisoners + + + align:start position:0% +there are there are Russian prisoners +and other kinds of prisoners as well + + align:start position:0% +and other kinds of prisoners as well + + + align:start position:0% +and other kinds of prisoners as well +there uh other kinds of prisoners as + + align:start position:0% +there uh other kinds of prisoners as + + + align:start position:0% +there uh other kinds of prisoners as +well there's a there's a sense that that + + align:start position:0% +well there's a there's a sense that that + + + align:start position:0% +well there's a there's a sense that that +that the prison camp is a kind of + + align:start position:0% +that the prison camp is a kind of + + + align:start position:0% +that the prison camp is a kind of +microcosm at least of Europe if not of + + align:start position:0% +microcosm at least of Europe if not of + + + align:start position:0% +microcosm at least of Europe if not of +if not of the world as a whole and more + + align:start position:0% +if not of the world as a whole and more + + + align:start position:0% +if not of the world as a whole and more +specifically the way in which the prison + + align:start position:0% +specifically the way in which the prison + + + align:start position:0% +specifically the way in which the prison +camp is a microcosm for the social + + align:start position:0% +camp is a microcosm for the social + + + align:start position:0% +camp is a microcosm for the social +striations that organize outer Society + + align:start position:0% +striations that organize outer Society + + + align:start position:0% +striations that organize outer Society +there's a working class there's a + + align:start position:0% +there's a working class there's a + + + align:start position:0% +there's a working class there's a +there's it seems to be a middle class + + align:start position:0% +there's it seems to be a middle class + + + align:start position:0% +there's it seems to be a middle class +you'll notice that there's a scholar who + + align:start position:0% +you'll notice that there's a scholar who + + + align:start position:0% +you'll notice that there's a scholar who +right who who who has a copy of pindar + + align:start position:0% +right who who who has a copy of pindar + + + align:start position:0% +right who who who has a copy of pindar +the the the great ancient uh uh poet uh + + align:start position:0% +the the the great ancient uh uh poet uh + + + align:start position:0% +the the the great ancient uh uh poet uh +who think and who who who Treasures his + + align:start position:0% +who think and who who who Treasures his + + + align:start position:0% +who think and who who who Treasures his +work on pin he's one of my favorite + + align:start position:0% +work on pin he's one of my favorite + + + align:start position:0% +work on pin he's one of my favorite +minor characters in the film because of + + align:start position:0% +minor characters in the film because of + + + align:start position:0% +minor characters in the film because of +his commitment to literature despite the + + align:start position:0% +his commitment to literature despite the + + + align:start position:0% +his commitment to literature despite the +war and despite the miseries of prison + + align:start position:0% +war and despite the miseries of prison + + + align:start position:0% +war and despite the miseries of prison +camp right uh uh and what you what you + + align:start position:0% +camp right uh uh and what you what you + + + align:start position:0% +camp right uh uh and what you what you +can see is in a certain sense is that + + align:start position:0% +can see is in a certain sense is that + + + align:start position:0% +can see is in a certain sense is that +Renoir is delighted by the idea that a + + align:start position:0% +Renoir is delighted by the idea that a + + + align:start position:0% +Renoir is delighted by the idea that a +that a that a kind of microcosm is + + align:start position:0% +that a that a kind of microcosm is + + + align:start position:0% +that a that a kind of microcosm is +created and if you watch variations + + align:start position:0% +created and if you watch variations + + + align:start position:0% +created and if you watch variations +amongst the Frenchmen and again if you + + align:start position:0% +amongst the Frenchmen and again if you + + + align:start position:0% +amongst the Frenchmen and again if you +think about that fragment of a scene I + + align:start position:0% +think about that fragment of a scene I + + + align:start position:0% +think about that fragment of a scene I +showed you this afternoon of these + + align:start position:0% +showed you this afternoon of these + + + align:start position:0% +showed you this afternoon of these +characters at dinner table in the in uh + + align:start position:0% +characters at dinner table in the in uh + + + align:start position:0% +characters at dinner table in the in uh +in the uh in the prison camp you'll + + align:start position:0% +in the uh in the prison camp you'll + + + align:start position:0% +in the uh in the prison camp you'll +begin to see more fully how powerfully + + align:start position:0% +begin to see more fully how powerfully + + + align:start position:0% +begin to see more fully how powerfully +and interestingly complexly he + + align:start position:0% +and interestingly complexly he + + + align:start position:0% +and interestingly complexly he +differentiates his characters from each + + align:start position:0% +differentiates his characters from each + + + align:start position:0% +differentiates his characters from each +other uh uh that fragment that you saw I + + align:start position:0% +other uh uh that fragment that you saw I + + + align:start position:0% +other uh uh that fragment that you saw I +hope you realized one of the characters + + align:start position:0% +hope you realized one of the characters + + + align:start position:0% +hope you realized one of the characters +was an actor and you could tell that you + + align:start position:0% +was an actor and you could tell that you + + + align:start position:0% +was an actor and you could tell that you +it becomes clearer if you watch the + + align:start position:0% +it becomes clearer if you watch the + + + align:start position:0% +it becomes clearer if you watch the +whole scene but he's a he's a very + + align:start position:0% +whole scene but he's a he's a very + + + align:start position:0% +whole scene but he's a he's a very +histrionic and Theatrical character he + + align:start position:0% +histrionic and Theatrical character he + + + align:start position:0% +histrionic and Theatrical character he +bursts into to song all the time right + + align:start position:0% +bursts into to song all the time right + + + align:start position:0% +bursts into to song all the time right +uh and then there's the Aristocrat who's + + align:start position:0% +uh and then there's the Aristocrat who's + + + align:start position:0% +uh and then there's the Aristocrat who's +looking down his monacle very very uh uh + + align:start position:0% +looking down his monacle very very uh uh + + + align:start position:0% +looking down his monacle very very uh uh +uh austerely and it seems his lip seems + + align:start position:0% +uh austerely and it seems his lip seems + + + align:start position:0% +uh austerely and it seems his lip seems +curled in a permanent uh gesture of + + align:start position:0% +curled in a permanent uh gesture of + + + align:start position:0% +curled in a permanent uh gesture of +condescension uh uh and so forth uh + + align:start position:0% +condescension uh uh and so forth uh + + + align:start position:0% +condescension uh uh and so forth uh +watch how how how richly how complexly + + align:start position:0% +watch how how how richly how complexly + + + align:start position:0% +watch how how how richly how complexly +the characters are distinguished from + + align:start position:0% +the characters are distinguished from + + + align:start position:0% +the characters are distinguished from +each other by social class by profession + + align:start position:0% +each other by social class by profession + + + align:start position:0% +each other by social class by profession +by uh and so and so forth I don't want + + align:start position:0% +by uh and so and so forth I don't want + + + align:start position:0% +by uh and so and so forth I don't want +to romanticize or idealize what I'm this + + align:start position:0% +to romanticize or idealize what I'm this + + + align:start position:0% +to romanticize or idealize what I'm this +argument because I'm not suggesting that + + align:start position:0% +argument because I'm not suggesting that + + + align:start position:0% +argument because I'm not suggesting that +when he says it's a microcosm of the + + align:start position:0% +when he says it's a microcosm of the + + + align:start position:0% +when he says it's a microcosm of the +world he wants to celebrate that + + align:start position:0% +world he wants to celebrate that + + + align:start position:0% +world he wants to celebrate that +microcosm although he he's interested in + + align:start position:0% +microcosm although he he's interested in + + + align:start position:0% +microcosm although he he's interested in +it uh Renoir is also aware of the + + align:start position:0% +it uh Renoir is also aware of the + + + align:start position:0% +it uh Renoir is also aware of the +limitations that it's not as if he's + + align:start position:0% +limitations that it's not as if he's + + + align:start position:0% +limitations that it's not as if he's +suggesting that this is a perfect + + align:start position:0% +suggesting that this is a perfect + + + align:start position:0% +suggesting that this is a perfect +community at all one reason is they're + + align:start position:0% +community at all one reason is they're + + + align:start position:0% +community at all one reason is they're +forced together but they're being forced + + align:start position:0% +forced together but they're being forced + + + align:start position:0% +forced together but they're being forced +together uh makes them share forces them + + align:start position:0% +together uh makes them share forces them + + + align:start position:0% +together uh makes them share forces them +to come out of their limitations in + + align:start position:0% +to come out of their limitations in + + + align:start position:0% +to come out of their limitations in +certain way to overcome certain of their + + align:start position:0% +certain way to overcome certain of their + + + align:start position:0% +certain way to overcome certain of their +prejudices although never fully right + + align:start position:0% +prejudices although never fully right + + + align:start position:0% +prejudices although never fully right +but what it also does is reveal them and + + align:start position:0% +but what it also does is reveal them and + + + align:start position:0% +but what it also does is reveal them and +we can and we can see how both processes + + align:start position:0% +we can and we can see how both processes + + + align:start position:0% +we can and we can see how both processes +the the the the process of sort of + + align:start position:0% +the the the the process of sort of + + + align:start position:0% +the the the the process of sort of +adjusting uh to people different from + + align:start position:0% +adjusting uh to people different from + + + align:start position:0% +adjusting uh to people different from +yourself and maybe overcoming some of + + align:start position:0% +yourself and maybe overcoming some of + + + align:start position:0% +yourself and maybe overcoming some of +your class or racial prejudices is a + + align:start position:0% +your class or racial prejudices is a + + + align:start position:0% +your class or racial prejudices is a +part of the experience that the + + align:start position:0% +part of the experience that the + + + align:start position:0% +part of the experience that the +characters in the film have but another + + align:start position:0% +characters in the film have but another + + + align:start position:0% +characters in the film have but another +part of the experiences that they come + + align:start position:0% +part of the experiences that they come + + + align:start position:0% +part of the experiences that they come +up against the differences between them + + align:start position:0% +up against the differences between them + + + align:start position:0% +up against the differences between them +some of which can never be breached let + + align:start position:0% +some of which can never be breached let + + + align:start position:0% +some of which can never be breached let +me mention one scene which dramatizes + + align:start position:0% +me mention one scene which dramatizes + + + align:start position:0% +me mention one scene which dramatizes +this ambig ambiguity very deeply there's + + align:start position:0% +this ambig ambiguity very deeply there's + + + align:start position:0% +this ambig ambiguity very deeply there's +one moment in the film very powerful + + align:start position:0% +one moment in the film very powerful + + + align:start position:0% +one moment in the film very powerful +moment I think uh in which one charact + + align:start position:0% +moment I think uh in which one charact + + + align:start position:0% +moment I think uh in which one charact +in which the mar the the character + + align:start position:0% +in which the mar the the character + + + align:start position:0% +in which the mar the the character +played by um uh gabah the marelle + + align:start position:0% +played by um uh gabah the marelle + + + align:start position:0% +played by um uh gabah the marelle +character is wounded in a good part of + + align:start position:0% +character is wounded in a good part of + + + align:start position:0% +character is wounded in a good part of +the early part of the film and in fact + + align:start position:0% +the early part of the film and in fact + + + align:start position:0% +the early part of the film and in fact +in in the dinner scene that I showed you + + align:start position:0% +in in the dinner scene that I showed you + + + align:start position:0% +in in the dinner scene that I showed you +this afternoon uh you'll see that at a + + align:start position:0% +this afternoon uh you'll see that at a + + + align:start position:0% +this afternoon uh you'll see that at a +certain point his comrade sitting at the + + align:start position:0% +certain point his comrade sitting at the + + + align:start position:0% +certain point his comrade sitting at the +table cuts his meat for him because his + + align:start position:0% +table cuts his meat for him because his + + + align:start position:0% +table cuts his meat for him because his +hand is injured and uh I don't know if + + align:start position:0% +hand is injured and uh I don't know if + + + align:start position:0% +hand is injured and uh I don't know if +it's in this scene or a subsequent scene + + align:start position:0% +it's in this scene or a subsequent scene + + + align:start position:0% +it's in this scene or a subsequent scene +there's a moment when another character + + align:start position:0% +there's a moment when another character + + + align:start position:0% +there's a moment when another character +in the film washes marelle's feet why is + + align:start position:0% +in the film washes marelle's feet why is + + + align:start position:0% +in the film washes marelle's feet why is +foot + + align:start position:0% +foot + + + align:start position:0% +foot +washing uh instantly a symbolic thing + + align:start position:0% +washing uh instantly a symbolic thing + + + align:start position:0% +washing uh instantly a symbolic thing +who knows the + + align:start position:0% +who knows the + + + align:start position:0% +who knows the +answer likey all right there's a scene + + align:start position:0% +answer likey all right there's a scene + + + align:start position:0% +answer likey all right there's a scene +in the Bible in in in the 12th chapter + + align:start position:0% +in the Bible in in in the 12th chapter + + + align:start position:0% +in the Bible in in in the 12th chapter +of John uh in which in which in which + + align:start position:0% +of John uh in which in which in which + + + align:start position:0% +of John uh in which in which in which +Mary or Martha I can't remember which + + align:start position:0% +Mary or Martha I can't remember which + + + align:start position:0% +Mary or Martha I can't remember which +washes Christ's feet and then in the + + align:start position:0% +washes Christ's feet and then in the + + + align:start position:0% +washes Christ's feet and then in the +very next chapter and uh in the very + + align:start position:0% +very next chapter and uh in the very + + + align:start position:0% +very next chapter and uh in the very +next chapter it at the Last Supper + + align:start position:0% +next chapter it at the Last Supper + + + align:start position:0% +next chapter it at the Last Supper +Christ himself washes the feet of his + + align:start position:0% +Christ himself washes the feet of his + + + align:start position:0% +Christ himself washes the feet of his +disciples and in fact the washing of + + align:start position:0% +disciples and in fact the washing of + + + align:start position:0% +disciples and in fact the washing of +feet uh is is in Catholic and in certain + + align:start position:0% +feet uh is is in Catholic and in certain + + + align:start position:0% +feet uh is is in Catholic and in certain +other Christian uh um rituals uh an + + align:start position:0% +other Christian uh um rituals uh an + + + align:start position:0% +other Christian uh um rituals uh an +actual official ritual it used to be + + align:start position:0% +actual official ritual it used to be + + + align:start position:0% +actual official ritual it used to be +much more common than it is today but + + align:start position:0% +much more common than it is today but + + + align:start position:0% +much more common than it is today but +it's still done in certain Catholic + + align:start position:0% +it's still done in certain Catholic + + + align:start position:0% +it's still done in certain Catholic +countries uh uh at the at the Advent of + + align:start position:0% +countries uh uh at the at the Advent of + + + align:start position:0% +countries uh uh at the at the Advent of +the holy of Holy Week uh uh so it's a + + align:start position:0% +the holy of Holy Week uh uh so it's a + + + align:start position:0% +the holy of Holy Week uh uh so it's a +deeply symbolic act in which in which + + align:start position:0% +deeply symbolic act in which in which + + + align:start position:0% +deeply symbolic act in which in which +Christ himself is washing the feet of + + align:start position:0% +Christ himself is washing the feet of + + + align:start position:0% +Christ himself is washing the feet of +his disciples and and he and the message + + align:start position:0% +his disciples and and he and the message + + + align:start position:0% +his disciples and and he and the message +he gives is everyone uh uh you should + + align:start position:0% +he gives is everyone uh uh you should + + + align:start position:0% +he gives is everyone uh uh you should +now do this to your to your fellows uh + + align:start position:0% +now do this to your to your fellows uh + + + align:start position:0% +now do this to your to your fellows uh +uh the implication being no one is + + align:start position:0% +uh the implication being no one is + + + align:start position:0% +uh the implication being no one is +better than anyone else the implication + + align:start position:0% +better than anyone else the implication + + + align:start position:0% +better than anyone else the implication +a radical a radically democratic Vision + + align:start position:0% +a radical a radically democratic Vision + + + align:start position:0% +a radical a radically democratic Vision +in some sense of of of uh of God's love + + align:start position:0% +in some sense of of of uh of God's love + + + align:start position:0% +in some sense of of of uh of God's love +uh and uh where has this practice been + + align:start position:0% +uh and uh where has this practice been + + + align:start position:0% +uh and uh where has this practice been +recently very dramatically and publicly + + align:start position:0% +recently very dramatically and publicly + + + align:start position:0% +recently very dramatically and publicly +revived who's been doing it the Pope the + + align:start position:0% +revived who's been doing it the Pope the + + + align:start position:0% +revived who's been doing it the Pope the +new pope haven't you read about this the + + align:start position:0% +new pope haven't you read about this the + + + align:start position:0% +new pope haven't you read about this the +new pope has been doing this he's uh uh + + align:start position:0% +new pope has been doing this he's uh uh + + + align:start position:0% +new pope has been doing this he's uh uh +uh washing the feet of + + align:start position:0% +uh washing the feet of + + + align:start position:0% +uh washing the feet of +parishioners a symbolic gesture in which + + align:start position:0% +parishioners a symbolic gesture in which + + + align:start position:0% +parishioners a symbolic gesture in which +in which God's Emissary on Earth is + + align:start position:0% +in which God's Emissary on Earth is + + + align:start position:0% +in which God's Emissary on Earth is +behaving with the humility that Jesus + + align:start position:0% +behaving with the humility that Jesus + + + align:start position:0% +behaving with the humility that Jesus +Christ himself so what so the foot + + align:start position:0% +Christ himself so what so the foot + + + align:start position:0% +Christ himself so what so the foot +washing scene in in uh in in in uh U our + + align:start position:0% +washing scene in in uh in in in uh U our + + + align:start position:0% +washing scene in in uh in in in uh U our +film has this sort of resonance to it + + align:start position:0% +film has this sort of resonance to it + + + align:start position:0% +film has this sort of resonance to it +even though there's no there's no openly + + align:start position:0% +even though there's no there's no openly + + + align:start position:0% +even though there's no there's no openly +religious reference but of but it has a + + align:start position:0% +religious reference but of but it has a + + + align:start position:0% +religious reference but of but it has a +similar kind of significance and and and + + align:start position:0% +similar kind of significance and and and + + + align:start position:0% +similar kind of significance and and and +they're carrying on a kind of + + align:start position:0% +they're carrying on a kind of + + + align:start position:0% +they're carrying on a kind of +conversation as the as the feet are + + align:start position:0% +conversation as the as the feet are + + + align:start position:0% +conversation as the as the feet are +being washed and what you feel is boy + + align:start position:0% +being washed and what you feel is boy + + + align:start position:0% +being washed and what you feel is boy +what a moving scene uh nobody is in the + + align:start position:0% +what a moving scene uh nobody is in the + + + align:start position:0% +what a moving scene uh nobody is in the +man who's doing the washing doesn't feel + + align:start position:0% +man who's doing the washing doesn't feel + + + align:start position:0% +man who's doing the washing doesn't feel +that he's being condescended to or that + + align:start position:0% +that he's being condescended to or that + + + align:start position:0% +that he's being condescended to or that +he's being diminished in any way by + + align:start position:0% +he's being diminished in any way by + + + align:start position:0% +he's being diminished in any way by +doing it the man whose feet are being + + align:start position:0% +doing it the man whose feet are being + + + align:start position:0% +doing it the man whose feet are being +washed is not embarrassed to have it + + align:start position:0% +washed is not embarrassed to have it + + + align:start position:0% +washed is not embarrassed to have it +happen what a scene of solidarity and + + align:start position:0% +happen what a scene of solidarity and + + + align:start position:0% +happen what a scene of solidarity and +Community uh and and you could turn this + + align:start position:0% +Community uh and and you could turn this + + + align:start position:0% +Community uh and and you could turn this +you could become very you could you + + align:start position:0% +you could become very you could you + + + align:start position:0% +you could become very you could you +could wax very poetic about what a scene + + align:start position:0% +could wax very poetic about what a scene + + + align:start position:0% +could wax very poetic about what a scene +of community and yet watch how the scene + + align:start position:0% +of community and yet watch how the scene + + + align:start position:0% +of community and yet watch how the scene +ends there's a moment at which after + + align:start position:0% +ends there's a moment at which after + + + align:start position:0% +ends there's a moment at which after +they as he's drying his feet uh the the + + align:start position:0% +they as he's drying his feet uh the the + + + align:start position:0% +they as he's drying his feet uh the the +uh the foot washer uh marelle asked the + + align:start position:0% +uh the foot washer uh marelle asked the + + + align:start position:0% +uh the foot washer uh marelle asked the +foot washer what do you do for a living + + align:start position:0% +foot washer what do you do for a living + + + align:start position:0% +foot washer what do you do for a living +and at some point during their + + align:start position:0% +and at some point during their + + + align:start position:0% +and at some point during their +conversation he says oh I I he says I am + + align:start position:0% +conversation he says oh I I he says I am + + + align:start position:0% +conversation he says oh I I he says I am +a I I I am a cadas what that means is + + align:start position:0% +a I I I am a cadas what that means is + + + align:start position:0% +a I I I am a cadas what that means is +something like City Planning he's a city + + align:start position:0% +something like City Planning he's a city + + + align:start position:0% +something like City Planning he's a city +planner and so the Marell character + + align:start position:0% +planner and so the Marell character + + + align:start position:0% +planner and so the Marell character +hears this and they go on that at the + + align:start position:0% +hears this and they go on that at the + + + align:start position:0% +hears this and they go on that at the +very end of the scene marichelle turns + + align:start position:0% +very end of the scene marichelle turns + + + align:start position:0% +very end of the scene marichelle turns +to his foot washer and he says what does + + align:start position:0% +to his foot washer and he says what does + + + align:start position:0% +to his foot washer and he says what does +that mean + + align:start position:0% +that mean + + + align:start position:0% +that mean +kadas the implication being that their + + align:start position:0% +kadas the implication being that their + + + align:start position:0% +kadas the implication being that their +vocabularies aren't even the same that + + align:start position:0% +vocabularies aren't even the same that + + + align:start position:0% +vocabularies aren't even the same that +they what it what it dramatizes is the + + align:start position:0% +they what it what it dramatizes is the + + + align:start position:0% +they what it what it dramatizes is the +distance between them he's been sitting + + align:start position:0% +distance between them he's been sitting + + + align:start position:0% +distance between them he's been sitting +there having this conversation with him + + align:start position:0% +there having this conversation with him + + + align:start position:0% +there having this conversation with him +but he didn't even say GE I have no idea + + align:start position:0% +but he didn't even say GE I have no idea + + + align:start position:0% +but he didn't even say GE I have no idea +what that word means I certainly have no + + align:start position:0% +what that word means I certainly have no + + + align:start position:0% +what that word means I certainly have no +idea what you do for a living it's a way + + align:start position:0% +idea what you do for a living it's a way + + + align:start position:0% +idea what you do for a living it's a way +of reminding us yes they've come + + align:start position:0% +of reminding us yes they've come + + + align:start position:0% +of reminding us yes they've come +together yes they're sharing space yes + + align:start position:0% +together yes they're sharing space yes + + + align:start position:0% +together yes they're sharing space yes +they they're doing something very uh um + + align:start position:0% +they they're doing something very uh um + + + align:start position:0% +they they're doing something very uh um +that dramatizes human solidarity and yet + + align:start position:0% +that dramatizes human solidarity and yet + + + align:start position:0% +that dramatizes human solidarity and yet +all also how separated they are again + + align:start position:0% +all also how separated they are again + + + align:start position:0% +all also how separated they are again +and again in the film we have this sort + + align:start position:0% +and again in the film we have this sort + + + align:start position:0% +and again in the film we have this sort +of double experience in which we see + + align:start position:0% +of double experience in which we see + + + align:start position:0% +of double experience in which we see +characters uh um make contact with each + + align:start position:0% +characters uh um make contact with each + + + align:start position:0% +characters uh um make contact with each +other or even sacrifice for each other + + align:start position:0% +other or even sacrifice for each other + + + align:start position:0% +other or even sacrifice for each other +and at the same time we're aware of + + align:start position:0% +and at the same time we're aware of + + + align:start position:0% +and at the same time we're aware of +their differences watch for this it's + + align:start position:0% +their differences watch for this it's + + + align:start position:0% +their differences watch for this it's +very powerful and moving in words it's a + + align:start position:0% +very powerful and moving in words it's a + + + align:start position:0% +very powerful and moving in words it's a +form of moral realism in which the film + + align:start position:0% +form of moral realism in which the film + + + align:start position:0% +form of moral realism in which the film +refuses to simplify what it wants to say + + align:start position:0% +refuses to simplify what it wants to say + + + align:start position:0% +refuses to simplify what it wants to say +about Human Experience very powerful + + align:start position:0% +about Human Experience very powerful + + + align:start position:0% +about Human Experience very powerful +example of this in the relationship + + align:start position:0% +example of this in the relationship + + + align:start position:0% +example of this in the relationship +between the Jew rosental who of his + + align:start position:0% +between the Jew rosental who of his + + + align:start position:0% +between the Jew rosental who of his +wealth he's the heir of a department + + align:start position:0% +wealth he's the heir of a department + + + align:start position:0% +wealth he's the heir of a department +store Fortune right uh but because he's + + align:start position:0% +store Fortune right uh but because he's + + + align:start position:0% +store Fortune right uh but because he's +a Jew he and and because he's nvo reach + + align:start position:0% +a Jew he and and because he's nvo reach + + + align:start position:0% +a Jew he and and because he's nvo reach +he can never be part of the aristocracy + + align:start position:0% +he can never be part of the aristocracy + + + align:start position:0% +he can never be part of the aristocracy +uh uh his relation to the marishal + + align:start position:0% +uh uh his relation to the marishal + + + align:start position:0% +uh uh his relation to the marishal +character is very complex marelle as I + + align:start position:0% +character is very complex marelle as I + + + align:start position:0% +character is very complex marelle as I +mentioned this afternoon retains a kind + + align:start position:0% +mentioned this afternoon retains a kind + + + align:start position:0% +mentioned this afternoon retains a kind +of working class French workingclass + + align:start position:0% +of working class French workingclass + + + align:start position:0% +of working class French workingclass +characteristic anti-Semitism and and + + align:start position:0% +characteristic anti-Semitism and and + + + align:start position:0% +characteristic anti-Semitism and and +there are moments when you can feel the + + align:start position:0% +there are moments when you can feel the + + + align:start position:0% +there are moments when you can feel the +hostility between them when the two of + + align:start position:0% +hostility between them when the two of + + + align:start position:0% +hostility between them when the two of +them finally try to make an escape from + + align:start position:0% +them finally try to make an escape from + + + align:start position:0% +them finally try to make an escape from +the prison and they actually are away + + align:start position:0% +the prison and they actually are away + + + align:start position:0% +the prison and they actually are away +from one of the prisons for a while and + + align:start position:0% +from one of the prisons for a while and + + + align:start position:0% +from one of the prisons for a while and +you see the the the rosentel character + + align:start position:0% +you see the the the rosentel character + + + align:start position:0% +you see the the the rosentel character +hurts his foot and there's a moment in + + align:start position:0% +hurts his foot and there's a moment in + + + align:start position:0% +hurts his foot and there's a moment in +which it looks like gee if if the + + align:start position:0% +which it looks like gee if if the + + + align:start position:0% +which it looks like gee if if the +marelle character stays with him he's + + align:start position:0% +marelle character stays with him he's + + + align:start position:0% +marelle character stays with him he's +putting himself in danger as well and + + align:start position:0% +putting himself in danger as well and + + + align:start position:0% +putting himself in danger as well and +they get into a fight and one of them + + align:start position:0% +they get into a fight and one of them + + + align:start position:0% +they get into a fight and one of them +said the Roso says go away leave me + + align:start position:0% +said the Roso says go away leave me + + + align:start position:0% +said the Roso says go away leave me +alone leave and marelle says all right I + + align:start position:0% +alone leave and marelle says all right I + + + align:start position:0% +alone leave and marelle says all right I +will and it's a very wonderful scene + + align:start position:0% +will and it's a very wonderful scene + + + align:start position:0% +will and it's a very wonderful scene +because they start singing at each other + + align:start position:0% +because they start singing at each other + + + align:start position:0% +because they start singing at each other +and it's a form of singing hostility so + + align:start position:0% +and it's a form of singing hostility so + + + align:start position:0% +and it's a form of singing hostility so +there's a comic Dimension to it too it's + + align:start position:0% +there's a comic Dimension to it too it's + + + align:start position:0% +there's a comic Dimension to it too it's +really rich but what is also being + + align:start position:0% +really rich but what is also being + + + align:start position:0% +really rich but what is also being +dramatized there are the limitations of + + align:start position:0% +dramatized there are the limitations of + + + align:start position:0% +dramatized there are the limitations of +the characters are marelle's + + align:start position:0% +the characters are marelle's + + + align:start position:0% +the characters are marelle's +anti-Semitism Rises come comes to the + + align:start position:0% +anti-Semitism Rises come comes to the + + + align:start position:0% +anti-Semitism Rises come comes to the +surface their hostility toward each + + align:start position:0% +surface their hostility toward each + + + align:start position:0% +surface their hostility toward each +other comes to the surface at that + + align:start position:0% +other comes to the surface at that + + + align:start position:0% +other comes to the surface at that +moment although of course they also + + align:start position:0% +moment although of course they also + + + align:start position:0% +moment although of course they also +overcome it and there are many other + + align:start position:0% +overcome it and there are many other + + + align:start position:0% +overcome it and there are many other +such moments in the film uh the + + align:start position:0% +such moments in the film uh the + + + align:start position:0% +such moments in the film uh the +relationship between de and his German + + align:start position:0% +relationship between de and his German + + + align:start position:0% +relationship between de and his German +counterpart the + + align:start position:0% +counterpart the + + + align:start position:0% +counterpart the +Aristocrat um uh um the aristocratic + + align:start position:0% +Aristocrat um uh um the aristocratic + + + align:start position:0% +Aristocrat um uh um the aristocratic +German uh uh is also a version of this + + align:start position:0% +German uh uh is also a version of this + + + align:start position:0% +German uh uh is also a version of this +of this kind of thing so a as I've + + align:start position:0% +of this kind of thing so a as I've + + + align:start position:0% +of this kind of thing so a as I've +already implied a second central theme + + align:start position:0% +already implied a second central theme + + + align:start position:0% +already implied a second central theme +of the film has to do with what we met + + align:start position:0% +of the film has to do with what we met + + + align:start position:0% +of the film has to do with what we met +my might call uh barriers and boundaries + + align:start position:0% +my might call uh barriers and boundaries + + + align:start position:0% +my might call uh barriers and boundaries +there's the barrier of social class + + align:start position:0% +there's the barrier of social class + + + align:start position:0% +there's the barrier of social class +which I've mentioned already there's the + + align:start position:0% +which I've mentioned already there's the + + + align:start position:0% +which I've mentioned already there's the +barrier of of language and culture right + + align:start position:0% +barrier of of language and culture right + + + align:start position:0% +barrier of of language and culture right +the Germans and the French are at War + + align:start position:0% +the Germans and the French are at War + + + align:start position:0% +the Germans and the French are at War +right uh the Russians don't speak the + + align:start position:0% +right uh the Russians don't speak the + + + align:start position:0% +right uh the Russians don't speak the +same language as the Germans the English + + align:start position:0% +same language as the Germans the English + + + align:start position:0% +same language as the Germans the English +don't speak the same language as the + + align:start position:0% +don't speak the same language as the + + + align:start position:0% +don't speak the same language as the +French and again and again the what + + align:start position:0% +French and again and again the what + + + align:start position:0% +French and again and again the what +separates people is dramatized for us + + align:start position:0% +separates people is dramatized for us + + + align:start position:0% +separates people is dramatized for us +although there's also a longing in the + + align:start position:0% +although there's also a longing in the + + + align:start position:0% +although there's also a longing in the +film to transcend these boundaries they + + align:start position:0% +film to transcend these boundaries they + + + align:start position:0% +film to transcend these boundaries they +always they don't can't always be + + align:start position:0% +always they don't can't always be + + + align:start position:0% +always they don't can't always be +transcended sometimes these boundaries + + align:start position:0% +transcended sometimes these boundaries + + + align:start position:0% +transcended sometimes these boundaries +are shown to be foolish and trivial or + + align:start position:0% +are shown to be foolish and trivial or + + + align:start position:0% +are shown to be foolish and trivial or +or or or at best unhelpful right uh uh + + align:start position:0% +or or or at best unhelpful right uh uh + + + align:start position:0% +or or or at best unhelpful right uh uh +and we can think of many there are many + + align:start position:0% +and we can think of many there are many + + + align:start position:0% +and we can think of many there are many +examples in the film uh both of language + + align:start position:0% +examples in the film uh both of language + + + align:start position:0% +examples in the film uh both of language +and of geography as well as of social + + align:start position:0% +and of geography as well as of social + + + align:start position:0% +and of geography as well as of social +class but let me mention just U two of + + align:start position:0% +class but let me mention just U two of + + + align:start position:0% +class but let me mention just U two of +them there's one wonderful moment in the + + align:start position:0% +them there's one wonderful moment in the + + + align:start position:0% +them there's one wonderful moment in the +film The French prisoners have been + + align:start position:0% +film The French prisoners have been + + + align:start position:0% +film The French prisoners have been +digging a tunnel an escape tunnel uh and + + align:start position:0% +digging a tunnel an escape tunnel uh and + + + align:start position:0% +digging a tunnel an escape tunnel uh and +they've almost completed the tunnel when + + align:start position:0% +they've almost completed the tunnel when + + + align:start position:0% +they've almost completed the tunnel when +the Germans come and say all right we're + + align:start position:0% +the Germans come and say all right we're + + + align:start position:0% +the Germans come and say all right we're +moving you out of your barracks and + + align:start position:0% +moving you out of your barracks and + + + align:start position:0% +moving you out of your barracks and +we're putting these English prisoners in + + align:start position:0% +we're putting these English prisoners in + + + align:start position:0% +we're putting these English prisoners in +it's very so the French are very unhappy + + align:start position:0% +it's very so the French are very unhappy + + + align:start position:0% +it's very so the French are very unhappy +about this because they've almost + + align:start position:0% +about this because they've almost + + + align:start position:0% +about this because they've almost +completed their tunnel so at Great + + align:start position:0% +completed their tunnel so at Great + + + align:start position:0% +completed their tunnel so at Great +danger to himself the marishal character + + align:start position:0% +danger to himself the marishal character + + + align:start position:0% +danger to himself the marishal character +breaks + + align:start position:0% +breaks + + + align:start position:0% +breaks +ranks drop try he does it kind of trick + + align:start position:0% +ranks drop try he does it kind of trick + + + align:start position:0% +ranks drop try he does it kind of trick +where he drops his suitcase I think or + + align:start position:0% +where he drops his suitcase I think or + + + align:start position:0% +where he drops his suitcase I think or +someone and he bends over to try to pick + + align:start position:0% +someone and he bends over to try to pick + + + align:start position:0% +someone and he bends over to try to pick +it up to give him an excuse to talk to + + align:start position:0% +it up to give him an excuse to talk to + + + align:start position:0% +it up to give him an excuse to talk to +the English prisoners who are going to + + align:start position:0% +the English prisoners who are going to + + + align:start position:0% +the English prisoners who are going to +change places with them he wants to tell + + align:start position:0% +change places with them he wants to tell + + + align:start position:0% +change places with them he wants to tell +the English prisoners there's a tunnel + + align:start position:0% +the English prisoners there's a tunnel + + + align:start position:0% +the English prisoners there's a tunnel +you can escape right uh but it turns out + + align:start position:0% +you can escape right uh but it turns out + + + align:start position:0% +you can escape right uh but it turns out +he's not able to give him the message + + align:start position:0% +he's not able to give him the message + + + align:start position:0% +he's not able to give him the message +because the English don't understand + + align:start position:0% +because the English don't understand + + + align:start position:0% +because the English don't understand +French and he can't speak English so so + + align:start position:0% +French and he can't speak English so so + + + align:start position:0% +French and he can't speak English so so +they the English prisoners end up going + + align:start position:0% +they the English prisoners end up going + + + align:start position:0% +they the English prisoners end up going +into them but without ever knowing that + + align:start position:0% +into them but without ever knowing that + + + align:start position:0% +into them but without ever knowing that +there's a tunnel waiting for them that + + align:start position:0% +there's a tunnel waiting for them that + + + align:start position:0% +there's a tunnel waiting for them that +it's almost ready ready to be completed + + align:start position:0% +it's almost ready ready to be completed + + + align:start position:0% +it's almost ready ready to be completed +an example of the barrier that language + + align:start position:0% +an example of the barrier that language + + + align:start position:0% +an example of the barrier that language +uh the the way language separates people + + align:start position:0% +uh the the way language separates people + + + align:start position:0% +uh the the way language separates people +and in many in many ways can be said to + + align:start position:0% +and in many in many ways can be said to + + + align:start position:0% +and in many in many ways can be said to +be frustrating uh one more example at + + align:start position:0% +be frustrating uh one more example at + + + align:start position:0% +be frustrating uh one more example at +the very end of the film there's a + + align:start position:0% +the very end of the film there's a + + + align:start position:0% +the very end of the film there's a +moment when the two the two characters + + align:start position:0% +moment when the two the two characters + + + align:start position:0% +moment when the two the two characters +marishal and rosenal are making their + + align:start position:0% +marishal and rosenal are making their + + + align:start position:0% +marishal and rosenal are making their +escape across a great field a Great + + align:start position:0% +escape across a great field a Great + + + align:start position:0% +escape across a great field a Great +White Field of snow uh and they're + + align:start position:0% +White Field of snow uh and they're + + + align:start position:0% +White Field of snow uh and they're +running across the field and so and the + + align:start position:0% +running across the field and so and the + + + align:start position:0% +running across the field and so and the +camera backs up and we see them being + + align:start position:0% +camera backs up and we see them being + + + align:start position:0% +camera backs up and we see them being +watched by German soldiers one of the + + align:start position:0% +watched by German soldiers one of the + + + align:start position:0% +watched by German soldiers one of the +soldiers picks up his rifle he says + + align:start position:0% +soldiers picks up his rifle he says + + + align:start position:0% +soldiers picks up his rifle he says +they're making an escape and he starts + + align:start position:0% +they're making an escape and he starts + + + align:start position:0% +they're making an escape and he starts +to aim at him then all of a sudden he + + align:start position:0% +to aim at him then all of a sudden he + + + align:start position:0% +to aim at him then all of a sudden he +stops I think I can't remember the ex + + align:start position:0% +stops I think I can't remember the ex + + + align:start position:0% +stops I think I can't remember the ex +watch for this how it happens I think + + align:start position:0% +watch for this how it happens I think + + + align:start position:0% +watch for this how it happens I think +his partner says wait a minute hold off + + align:start position:0% +his partner says wait a minute hold off + + + align:start position:0% +his partner says wait a minute hold off +why doesn't he shoot and then we see + + align:start position:0% +why doesn't he shoot and then we see + + + align:start position:0% +why doesn't he shoot and then we see +marelle and rosental could disappear or + + align:start position:0% +marelle and rosental could disappear or + + + align:start position:0% +marelle and rosental could disappear or +cross the cross an invisible boundary + + align:start position:0% +cross the cross an invisible boundary + + + align:start position:0% +cross the cross an invisible boundary +and the and the Germans says well + + align:start position:0% +and the and the Germans says well + + + align:start position:0% +and the and the Germans says well +they've crossed the border they're no + + align:start position:0% +they've crossed the border they're no + + + align:start position:0% +they've crossed the border they're no +longer in Germany I can't shoot them + + align:start position:0% +longer in Germany I can't shoot them + + + align:start position:0% +longer in Germany I can't shoot them +they're in they're now in Belgium but + + align:start position:0% +they're in they're now in Belgium but + + + align:start position:0% +they're in they're now in Belgium but +the fact is there's no boundary there + + align:start position:0% +the fact is there's no boundary there + + + align:start position:0% +the fact is there's no boundary there +it's all snow it's a snowy field right + + align:start position:0% +it's all snow it's a snowy field right + + + align:start position:0% +it's all snow it's a snowy field right +how arbitrary that boundary is well + + align:start position:0% +how arbitrary that boundary is well + + + align:start position:0% +how arbitrary that boundary is well +again and again in the film we have this + + align:start position:0% +again and again in the film we have this + + + align:start position:0% +again and again in the film we have this +theme of barriers and boundaries what + + align:start position:0% +theme of barriers and boundaries what + + + align:start position:0% +theme of barriers and boundaries what +separates us uh and also one last thing + + align:start position:0% +separates us uh and also one last thing + + + align:start position:0% +separates us uh and also one last thing +about the question of social class maybe + + align:start position:0% +about the question of social class maybe + + + align:start position:0% +about the question of social class maybe +the most disturbing and Powerful Insight + + align:start position:0% +the most disturbing and Powerful Insight + + + align:start position:0% +the most disturbing and Powerful Insight +that the film has about social class one + + align:start position:0% +that the film has about social class one + + + align:start position:0% +that the film has about social class one +that Americans tend to resist but I + + align:start position:0% +that Americans tend to resist but I + + + align:start position:0% +that Americans tend to resist but I +encourage you not to resist it those of + + align:start position:0% +encourage you not to resist it those of + + + align:start position:0% +encourage you not to resist it those of +you not from the United States will + + align:start position:0% +you not from the United States will + + + align:start position:0% +you not from the United States will +perhaps understand this more easily + + align:start position:0% +perhaps understand this more easily + + + align:start position:0% +perhaps understand this more easily +although Americans need to understand it + + align:start position:0% +although Americans need to understand it + + + align:start position:0% +although Americans need to understand it +is the extent to which one social class + + align:start position:0% +is the extent to which one social class + + + align:start position:0% +is the extent to which one social class +shapes one's identity that is to say one + + align:start position:0% +shapes one's identity that is to say one + + + align:start position:0% +shapes one's identity that is to say one +of the things we feel in this film is + + align:start position:0% +of the things we feel in this film is + + + align:start position:0% +of the things we feel in this film is +that well Jew's nature is a function of + + align:start position:0% +that well Jew's nature is a function of + + + align:start position:0% +that well Jew's nature is a function of +his having been raised as an aristocrat + + align:start position:0% +his having been raised as an aristocrat + + + align:start position:0% +his having been raised as an aristocrat +there are wonderful scenes between du + + align:start position:0% +there are wonderful scenes between du + + + align:start position:0% +there are wonderful scenes between du +and marel where marel says to him + + align:start position:0% +and marel where marel says to him + + + align:start position:0% +and marel where marel says to him +there's a wall between us uh and uh + + align:start position:0% +there's a wall between us uh and uh + + + align:start position:0% +there's a wall between us uh and uh +you're so undemonstrative and you + + align:start position:0% +you're so undemonstrative and you + + + align:start position:0% +you're so undemonstrative and you +marelle doesn't trust him because he + + align:start position:0% +marelle doesn't trust him because he + + + align:start position:0% +marelle doesn't trust him because he +because he belongs to belongs to a + + align:start position:0% +because he belongs to belongs to a + + + align:start position:0% +because he belongs to belongs to a +different class even though of course + + align:start position:0% +different class even though of course + + + align:start position:0% +different class even though of course +they're Frenchmen after all and in the + + align:start position:0% +they're Frenchmen after all and in the + + + align:start position:0% +they're Frenchmen after all and in the +end nationality Trump's class in this in + + align:start position:0% +end nationality Trump's class in this in + + + align:start position:0% +end nationality Trump's class in this in +this film uh as you'll as you'll see uh + + align:start position:0% +this film uh as you'll as you'll see uh + + + align:start position:0% +this film uh as you'll as you'll see uh +but in this kind in this in this sort of + + align:start position:0% +but in this kind in this in this sort of + + + align:start position:0% +but in this kind in this in this sort of +uh distinction or difference between + + align:start position:0% +uh distinction or difference between + + + align:start position:0% +uh distinction or difference between +marelle and duio we have another + + align:start position:0% +marelle and duio we have another + + + align:start position:0% +marelle and duio we have another +expression of this of this sense of of + + align:start position:0% +expression of this of this sense of of + + + align:start position:0% +expression of this of this sense of of +of this idea or this recognition that + + align:start position:0% +of this idea or this recognition that + + + align:start position:0% +of this idea or this recognition that +one's personality + + align:start position:0% +one's personality + + + align:start position:0% +one's personality +itself what one likes and dislikes one's + + align:start position:0% +itself what one likes and dislikes one's + + + align:start position:0% +itself what one likes and dislikes one's +fundamental nature is in part shaped by + + align:start position:0% +fundamental nature is in part shaped by + + + align:start position:0% +fundamental nature is in part shaped by +the class into which one is born we're + + align:start position:0% +the class into which one is born we're + + + align:start position:0% +the class into which one is born we're +not born utterly free we don't have + + align:start position:0% +not born utterly free we don't have + + + align:start position:0% +not born utterly free we don't have +absolute choice in what we are or what + + align:start position:0% +absolute choice in what we are or what + + + align:start position:0% +absolute choice in what we are or what +we become our characters are shaped + + align:start position:0% +we become our characters are shaped + + + align:start position:0% +we become our characters are shaped +controlled by the circumstances in which + + align:start position:0% +controlled by the circumstances in which + + + align:start position:0% +controlled by the circumstances in which +we uh live and the film profoundly + + align:start position:0% +we uh live and the film profoundly + + + align:start position:0% +we uh live and the film profoundly +understands that it understands our + + align:start position:0% +understands that it understands our + + + align:start position:0% +understands that it understands our +desire to breach those limitations to to + + align:start position:0% +desire to breach those limitations to to + + + align:start position:0% +desire to breach those limitations to to +go beyond them and it celebrates our + + align:start position:0% +go beyond them and it celebrates our + + + align:start position:0% +go beyond them and it celebrates our +impulse to do so but it also recognizes + + align:start position:0% +impulse to do so but it also recognizes + + + align:start position:0% +impulse to do so but it also recognizes +the degree to which we remain confined + + align:start position:0% +the degree to which we remain confined + + + align:start position:0% +the degree to which we remain confined +within personalities that are partly + + align:start position:0% +within personalities that are partly + + + align:start position:0% +within personalities that are partly +controlled or shaped by forces far + + align:start position:0% +controlled or shaped by forces far + + + align:start position:0% +controlled or shaped by forces far +beyond our individual control and that + + align:start position:0% +beyond our individual control and that + + + align:start position:0% +beyond our individual control and that +are especially located in the social + + align:start position:0% +are especially located in the social + + + align:start position:0% +are especially located in the social +class to which we belong finally as I + + align:start position:0% +class to which we belong finally as I + + + align:start position:0% +class to which we belong finally as I +mentioned this afternoon the theme of + + align:start position:0% +mentioned this afternoon the theme of + + + align:start position:0% +mentioned this afternoon the theme of +historical transition is at the heart of + + align:start position:0% +historical transition is at the heart of + + + align:start position:0% +historical transition is at the heart of +this remarkable film and you'll + + align:start position:0% +this remarkable film and you'll + + + align:start position:0% +this remarkable film and you'll +understand very clearly what is going on + + align:start position:0% +understand very clearly what is going on + + + align:start position:0% +understand very clearly what is going on +there again dramatized even more + + align:start position:0% +there again dramatized even more + + + align:start position:0% +there again dramatized even more +complexly and fully in rules of the game + + align:start position:0% +complexly and fully in rules of the game + + + align:start position:0% +complexly and fully in rules of the game +it's a central topic here the an arist + + align:start position:0% +it's a central topic here the an arist + + + align:start position:0% +it's a central topic here the an arist +an aristocratic Traditions are giving + + align:start position:0% +an aristocratic Traditions are giving + + + align:start position:0% +an aristocratic Traditions are giving +way to modernity in this + + align:start position:0% +way to modernity in this + + + align:start position:0% +way to modernity in this +film and we're aware of them in all + + align:start position:0% +film and we're aware of them in all + + + align:start position:0% +film and we're aware of them in all +kinds of ways even in the nostalgic way + + align:start position:0% +kinds of ways even in the nostalgic way + + + align:start position:0% +kinds of ways even in the nostalgic way +in which du + + align:start position:0% +in which du + + + align:start position:0% +in which du +and ralen Stein carry on their + + align:start position:0% +and ralen Stein carry on their + + + align:start position:0% +and ralen Stein carry on their +conversations they talk about they know + + align:start position:0% +conversations they talk about they know + + + align:start position:0% +conversations they talk about they know +they have they have experiences in + + align:start position:0% +they have they have experiences in + + + align:start position:0% +they have they have experiences in +common because they belong to the + + align:start position:0% +common because they belong to the + + + align:start position:0% +common because they belong to the +aristocracy a a a class that transcended + + align:start position:0% +aristocracy a a a class that transcended + + + align:start position:0% +aristocracy a a a class that transcended +in some sense or at least in part + + align:start position:0% +in some sense or at least in part + + + align:start position:0% +in some sense or at least in part +transcended National Origins that + + align:start position:0% +transcended National Origins that + + + align:start position:0% +transcended National Origins that +aristocratic dispensation is + + align:start position:0% +aristocratic dispensation is + + + align:start position:0% +aristocratic dispensation is +disappearing in fact this first world + + align:start position:0% +disappearing in fact this first world + + + align:start position:0% +disappearing in fact this first world +war completely obliterated it and Renoir + + align:start position:0% +war completely obliterated it and Renoir + + + align:start position:0% +war completely obliterated it and Renoir +is not the only one who have said this + + align:start position:0% +is not the only one who have said this + + + align:start position:0% +is not the only one who have said this +there are number of wonderful uh U uh + + align:start position:0% +there are number of wonderful uh U uh + + + align:start position:0% +there are number of wonderful uh U uh +apart from scholarship there are number + + align:start position:0% +apart from scholarship there are number + + + align:start position:0% +apart from scholarship there are number +of wonderful novels for example that + + align:start position:0% +of wonderful novels for example that + + + align:start position:0% +of wonderful novels for example that +deal with this with the with the + + align:start position:0% +deal with this with the with the + + + align:start position:0% +deal with this with the with the +transformation of European Society + + align:start position:0% +transformation of European Society + + + align:start position:0% +transformation of European Society +because of the uh because of the first + + align:start position:0% +because of the uh because of the first + + + align:start position:0% +because of the uh because of the first +world war and renoir's film is is uh is + + align:start position:0% +world war and renoir's film is is uh is + + + align:start position:0% +world war and renoir's film is is uh is +one such is one such + + align:start position:0% + + + + align:start position:0% + +text renoir's + + align:start position:0% +text renoir's + + + align:start position:0% +text renoir's +maturity this is another way of talking + + align:start position:0% +maturity this is another way of talking + + + align:start position:0% +maturity this is another way of talking +about the complexity or the richness of + + align:start position:0% +about the complexity or the richness of + + + align:start position:0% +about the complexity or the richness of +his films but it's a I simply want to + + align:start position:0% +his films but it's a I simply want to + + + align:start position:0% +his films but it's a I simply want to +remind you at the end that one one way + + align:start position:0% +remind you at the end that one one way + + + align:start position:0% +remind you at the end that one one way +to think about what Renoir is doing is + + align:start position:0% +to think about what Renoir is doing is + + + align:start position:0% +to think about what Renoir is doing is +is to recognize that his his visual + + align:start position:0% +is to recognize that his his visual + + + align:start position:0% +is to recognize that his his visual +style is in some sense an embodiment of + + align:start position:0% +style is in some sense an embodiment of + + + align:start position:0% +style is in some sense an embodiment of +the ambition not to simplify right to be + + align:start position:0% +the ambition not to simplify right to be + + + align:start position:0% +the ambition not to simplify right to be +as fluid and as attentive to the world + + align:start position:0% +as fluid and as attentive to the world + + + align:start position:0% +as fluid and as attentive to the world +as it's possible to be and one can see + + align:start position:0% +as it's possible to be and one can see + + + align:start position:0% +as it's possible to be and one can see +that that one could say that that visual + + align:start position:0% +that that one could say that that visual + + + align:start position:0% +that that one could say that that visual +that that that commitment to that + + align:start position:0% +that that that commitment to that + + + align:start position:0% +that that that commitment to that +commitment to the way the camera acts + + align:start position:0% +commitment to the way the camera acts + + + align:start position:0% +commitment to the way the camera acts +toward the world is a version of a + + align:start position:0% +toward the world is a version of a + + + align:start position:0% +toward the world is a version of a +larger kind of U maturity or complexity + + align:start position:0% +larger kind of U maturity or complexity + + + align:start position:0% +larger kind of U maturity or complexity +that's revealed in the content of his + + align:start position:0% +that's revealed in the content of his + + + align:start position:0% +that's revealed in the content of his +work as well take the characters I've + + align:start position:0% +work as well take the characters I've + + + align:start position:0% +work as well take the characters I've +already mentioned the key Point here the + + align:start position:0% +already mentioned the key Point here the + + + align:start position:0% +already mentioned the key Point here the +way in which the characters are both + + align:start position:0% +way in which the characters are both + + + align:start position:0% +way in which the characters are both +flawed full of weaknesses but also + + align:start position:0% +flawed full of weaknesses but also + + + align:start position:0% +flawed full of weaknesses but also +attractive in certain ways the way in + + align:start position:0% +attractive in certain ways the way in + + + align:start position:0% +attractive in certain ways the way in +which rosenal is marred by his pride in + + align:start position:0% +which rosenal is marred by his pride in + + + align:start position:0% +which rosenal is marred by his pride in +his family's wealth uh the way in which + + align:start position:0% +his family's wealth uh the way in which + + + align:start position:0% +his family's wealth uh the way in which +the gabang character is marred by his + + align:start position:0% +the gabang character is marred by his + + + align:start position:0% +the gabang character is marred by his +anti-Semitism and his lack of Education + + align:start position:0% +anti-Semitism and his lack of Education + + + align:start position:0% +anti-Semitism and his lack of Education +the way in which the Dadu character is + + align:start position:0% +the way in which the Dadu character is + + + align:start position:0% +the way in which the Dadu character is +damaged or limited by the by his by his + + align:start position:0% +damaged or limited by the by his by his + + + align:start position:0% +damaged or limited by the by his by his +aristocratic reserve and his impulse + + align:start position:0% +aristocratic reserve and his impulse + + + align:start position:0% +aristocratic reserve and his impulse +toward a kind of descending superiority + + align:start position:0% +toward a kind of descending superiority + + + align:start position:0% +toward a kind of descending superiority +which you can see articulated in the + + align:start position:0% +which you can see articulated in the + + + align:start position:0% +which you can see articulated in the +very first moment you see him at the + + align:start position:0% +very first moment you see him at the + + + align:start position:0% +very first moment you see him at the +very beginning of the film where he's + + align:start position:0% +very beginning of the film where he's + + + align:start position:0% +very beginning of the film where he's +tisk tisking about the incompetence of + + align:start position:0% +tisk tisking about the incompetence of + + + align:start position:0% +tisk tisking about the incompetence of +his own troops um so there's a + + align:start position:0% +his own troops um so there's a + + + align:start position:0% +his own troops um so there's a +complexity of character that reflects + + align:start position:0% +complexity of character that reflects + + + align:start position:0% +complexity of character that reflects +the maturity of the film's vision of + + align:start position:0% +the maturity of the film's vision of + + + align:start position:0% +the maturity of the film's vision of +life and there's a complexity in the + + align:start position:0% +life and there's a complexity in the + + + align:start position:0% +life and there's a complexity in the +story because think of it for a minute + + align:start position:0% +story because think of it for a minute + + + align:start position:0% +story because think of it for a minute +this is a war story but it's a war story + + align:start position:0% +this is a war story but it's a war story + + + align:start position:0% +this is a war story but it's a war story +without battles some people have said + + align:start position:0% +without battles some people have said + + + align:start position:0% +without battles some people have said +it's the happiest War Story they ever + + align:start position:0% +it's the happiest War Story they ever + + + align:start position:0% +it's the happiest War Story they ever +saw one way of organizing the film is to + + align:start position:0% +saw one way of organizing the film is to + + + align:start position:0% +saw one way of organizing the film is to +see it as a series of meals uh in which + + align:start position:0% +see it as a series of meals uh in which + + + align:start position:0% +see it as a series of meals uh in which +in which characters sit down at table + + align:start position:0% +in which characters sit down at table + + + align:start position:0% +in which characters sit down at table +and share convivial thoughts right it's + + align:start position:0% +and share convivial thoughts right it's + + + align:start position:0% +and share convivial thoughts right it's +not only not a sufficient way of + + align:start position:0% +not only not a sufficient way of + + + align:start position:0% +not only not a sufficient way of +thinking about the F but it's a partial + + align:start position:0% +thinking about the F but it's a partial + + + align:start position:0% +thinking about the F but it's a partial +way of thinking about it so so although + + align:start position:0% +way of thinking about it so so although + + + align:start position:0% +way of thinking about it so so although +it's a a film about war about the + + align:start position:0% +it's a a film about war about the + + + align:start position:0% +it's a a film about war about the +consequences of War it doesn't show + + align:start position:0% +consequences of War it doesn't show + + + align:start position:0% +consequences of War it doesn't show +shooting and in fact although it's a war + + align:start position:0% +shooting and in fact although it's a war + + + align:start position:0% +shooting and in fact although it's a war +story it's about most deeply human + + align:start position:0% +story it's about most deeply human + + + align:start position:0% +story it's about most deeply human +community and human solidarity and about + + align:start position:0% +community and human solidarity and about + + + align:start position:0% +community and human solidarity and about +historical transition well one way to + + align:start position:0% +historical transition well one way to + + + align:start position:0% +historical transition well one way to +crystallize all of this or to summarize + + align:start position:0% +crystallize all of this or to summarize + + + align:start position:0% +crystallize all of this or to summarize +it is to remind you of the complexity of + + align:start position:0% +it is to remind you of the complexity of + + + align:start position:0% +it is to remind you of the complexity of +the title Grand Illusion what could the + + align:start position:0% +the title Grand Illusion what could the + + + align:start position:0% +the title Grand Illusion what could the +the title seems to me to have at least + + align:start position:0% +the title seems to me to have at least + + + align:start position:0% +the title seems to me to have at least +four separate implications or four + + align:start position:0% +four separate implications or four + + + align:start position:0% +four separate implications or four +separate ways of understanding and the + + align:start position:0% +separate ways of understanding and the + + + align:start position:0% +separate ways of understanding and the +fact that it's it's a measure of what + + align:start position:0% +fact that it's it's a measure of what + + + align:start position:0% +fact that it's it's a measure of what +I've called multiplicity or complexity + + align:start position:0% +I've called multiplicity or complexity + + + align:start position:0% +I've called multiplicity or complexity +right how what would what what would the + + align:start position:0% +right how what would what what would the + + + align:start position:0% +right how what would what what would the +title mean what what is the Grand + + align:start position:0% +title mean what what is the Grand + + + align:start position:0% +title mean what what is the Grand +Illusion to which the title refers well + + align:start position:0% +Illusion to which the title refers well + + + align:start position:0% +Illusion to which the title refers well +one is surely this uh remember the film + + align:start position:0% +one is surely this uh remember the film + + + align:start position:0% +one is surely this uh remember the film +was made on the eve of World War II even + + align:start position:0% +was made on the eve of World War II even + + + align:start position:0% +was made on the eve of World War II even +though it is ostensibly set in World War + + align:start position:0% +though it is ostensibly set in World War + + + align:start position:0% +though it is ostensibly set in World War +I and in fact it was recognized as an + + align:start position:0% +I and in fact it was recognized as an + + + align:start position:0% +I and in fact it was recognized as an +anti-war film it was banned in Germany + + align:start position:0% +anti-war film it was banned in Germany + + + align:start position:0% +anti-war film it was banned in Germany +and in Italy President Roosevelt in the + + align:start position:0% +and in Italy President Roosevelt in the + + + align:start position:0% +and in Italy President Roosevelt in the +United States said anyone who loves + + align:start position:0% +United States said anyone who loves + + + align:start position:0% +United States said anyone who loves +Freedom should see this film I think he + + align:start position:0% +Freedom should see this film I think he + + + align:start position:0% +Freedom should see this film I think he +was + + align:start position:0% +was + + + align:start position:0% +was +right the title one of the things about + + align:start position:0% +right the title one of the things about + + + align:start position:0% +right the title one of the things about +that War uh that first world war as some + + align:start position:0% +that War uh that first world war as some + + + align:start position:0% +that War uh that first world war as some +of you will know was it was identified + + align:start position:0% +of you will know was it was identified + + + align:start position:0% +of you will know was it was identified +especially by the American president + + align:start position:0% +especially by the American president + + + align:start position:0% +especially by the American president +woodro Wilson as the war to end Wars so + + align:start position:0% +woodro Wilson as the war to end Wars so + + + align:start position:0% +woodro Wilson as the war to end Wars so +one deep Grand but horrible illusion is + + align:start position:0% +one deep Grand but horrible illusion is + + + align:start position:0% +one deep Grand but horrible illusion is +that this is the war to end Wars that + + align:start position:0% +that this is the war to end Wars that + + + align:start position:0% +that this is the war to end Wars that +there won't be any more war Wars after + + align:start position:0% +there won't be any more war Wars after + + + align:start position:0% +there won't be any more war Wars after +this one right uh a second possible + + align:start position:0% +this one right uh a second possible + + + align:start position:0% +this one right uh a second possible +meaning of the title is this um uh + + align:start position:0% +meaning of the title is this um uh + + + align:start position:0% +meaning of the title is this um uh +there's a one of the central events in + + align:start position:0% +there's a one of the central events in + + + align:start position:0% +there's a one of the central events in +the film I haven't mentioned yet and + + align:start position:0% +the film I haven't mentioned yet and + + + align:start position:0% +the film I haven't mentioned yet and +it's it's maybe the most memorable + + align:start position:0% +it's it's maybe the most memorable + + + align:start position:0% +it's it's maybe the most memorable +interlude in the film is after marishal + + align:start position:0% +interlude in the film is after marishal + + + align:start position:0% +interlude in the film is after marishal +and Rosenthal make their escape from one + + align:start position:0% +and Rosenthal make their escape from one + + + align:start position:0% +and Rosenthal make their escape from one +of the prison camps they're on the Run + + align:start position:0% +of the prison camps they're on the Run + + + align:start position:0% +of the prison camps they're on the Run +they can't be they they but they're in + + align:start position:0% +they can't be they they but they're in + + + align:start position:0% +they can't be they they but they're in +Germany and they're it's the middle of + + align:start position:0% +Germany and they're it's the middle of + + + align:start position:0% +Germany and they're it's the middle of +winter and they managed to find uh uh uh + + align:start position:0% +winter and they managed to find uh uh uh + + + align:start position:0% +winter and they managed to find uh uh uh +safety in the home of a of of a German + + align:start position:0% +safety in the home of a of of a German + + + align:start position:0% +safety in the home of a of of a German +woman who is whose husband is away at + + align:start position:0% +woman who is whose husband is away at + + + align:start position:0% +woman who is whose husband is away at +the war uh perhaps dead and uh she she + + align:start position:0% +the war uh perhaps dead and uh she she + + + align:start position:0% +the war uh perhaps dead and uh she she +is there trying to manage a farm with + + align:start position:0% +is there trying to manage a farm with + + + align:start position:0% +is there trying to manage a farm with +her young daughter Elsie and Elsa and + + align:start position:0% +her young daughter Elsie and Elsa and + + + align:start position:0% +her young daughter Elsie and Elsa and +and marishal and rosenal spend the + + align:start position:0% +and marishal and rosenal spend the + + + align:start position:0% +and marishal and rosenal spend the +winter with them and and they get and + + align:start position:0% +winter with them and and they get and + + + align:start position:0% +winter with them and and they get and +it's it's an idol in the winter so think + + align:start position:0% +it's it's an idol in the winter so think + + + align:start position:0% +it's it's an idol in the winter so think +about what and F is very moving and + + align:start position:0% +about what and F is very moving and + + + align:start position:0% +about what and F is very moving and +again the barriers of language are + + align:start position:0% +again the barriers of language are + + + align:start position:0% +again the barriers of language are +present there at the very end of the of + + align:start position:0% +present there at the very end of the of + + + align:start position:0% +present there at the very end of the of +their Idol in the woods we have marishal + + align:start position:0% +their Idol in the woods we have marishal + + + align:start position:0% +their Idol in the woods we have marishal +say to to the child I think her name is + + align:start position:0% +say to to the child I think her name is + + + align:start position:0% +say to to the child I think her name is +I I called her Elsa I think it's LTI um + + align:start position:0% +I I called her Elsa I think it's LTI um + + + align:start position:0% +I I called her Elsa I think it's LTI um +he says he looks at the girl he says + + align:start position:0% +he says he looks at the girl he says + + + align:start position:0% +he says he looks at the girl he says +says he he tried in bad German he says + + align:start position:0% +says he he tried in bad German he says + + + align:start position:0% +says he he tried in bad German he says +LTI has blow he says blue eyes but he's + + align:start position:0% +LTI has blow he says blue eyes but he's + + + align:start position:0% +LTI has blow he says blue eyes but he's +very proud of himself for having been + + align:start position:0% +very proud of himself for having been + + + align:start position:0% +very proud of himself for having been +able to articulate two German words but + + align:start position:0% +able to articulate two German words but + + + align:start position:0% +able to articulate two German words but +the fact that he's done that is a mark + + align:start position:0% +the fact that he's done that is a mark + + + align:start position:0% +the fact that he's done that is a mark +of his having you reached out and and + + align:start position:0% +of his having you reached out and and + + + align:start position:0% +of his having you reached out and and +the implication more than an implication + + align:start position:0% +the implication more than an implication + + + align:start position:0% +the implication more than an implication +is he becomes the woman's lover uh uh uh + + align:start position:0% +is he becomes the woman's lover uh uh uh + + + align:start position:0% +is he becomes the woman's lover uh uh uh +uh while they're while they spend the + + align:start position:0% +uh while they're while they spend the + + + align:start position:0% +uh while they're while they spend the +winter in this and and the German woman + + align:start position:0% +winter in this and and the German woman + + + align:start position:0% +winter in this and and the German woman +uh at a certain point when they first + + align:start position:0% +uh at a certain point when they first + + + align:start position:0% +uh at a certain point when they first +take refuge in her place the door a + + align:start position:0% +take refuge in her place the door a + + + align:start position:0% +take refuge in her place the door a +German Soldier searching for these guys + + align:start position:0% +German Soldier searching for these guys + + + align:start position:0% +German Soldier searching for these guys +comes to the comes to the door comes to + + align:start position:0% +comes to the comes to the door comes to + + + align:start position:0% +comes to the comes to the door comes to +the window and speaks to the Widow and + + align:start position:0% +the window and speaks to the Widow and + + + align:start position:0% +the window and speaks to the Widow and +the Widow protects them right so so a + + align:start position:0% +the Widow protects them right so so a + + + align:start position:0% +the Widow protects them right so so a +second Grand Illusion may very well be + + align:start position:0% +second Grand Illusion may very well be + + + align:start position:0% +second Grand Illusion may very well be +look this is a very lovely story but how + + align:start position:0% +look this is a very lovely story but how + + + align:start position:0% +look this is a very lovely story but how +believable is it Germans French soldiers + + align:start position:0% +believable is it Germans French soldiers + + + align:start position:0% +believable is it Germans French soldiers +on the run from a prison camp find find + + align:start position:0% +on the run from a prison camp find find + + + align:start position:0% +on the run from a prison camp find find +a a farmhouse in which a German Widow + + align:start position:0% +a a farmhouse in which a German Widow + + + align:start position:0% +a a farmhouse in which a German Widow +takes them in and protects them from the + + align:start position:0% +takes them in and protects them from the + + + align:start position:0% +takes them in and protects them from the +German soldiers that would be it's a + + align:start position:0% +German soldiers that would be it's a + + + align:start position:0% +German soldiers that would be it's a +nice story but is it a grand ill if it + + align:start position:0% +nice story but is it a grand ill if it + + + align:start position:0% +nice story but is it a grand ill if it +is an illusion maybe it's a grand one a + + align:start position:0% +is an illusion maybe it's a grand one a + + + align:start position:0% +is an illusion maybe it's a grand one a +wonderful one not just a large one but a + + align:start position:0% +wonderful one not just a large one but a + + + align:start position:0% +wonderful one not just a large one but a +valuable one right so that's a second + + align:start position:0% +valuable one right so that's a second + + + align:start position:0% +valuable one right so that's a second +way in which the the uh title resonates + + align:start position:0% +way in which the the uh title resonates + + + align:start position:0% +way in which the the uh title resonates +for me um um uh the third Grand Illusion + + align:start position:0% +for me um um uh the third Grand Illusion + + + align:start position:0% +for me um um uh the third Grand Illusion +has to do with the community of the + + align:start position:0% +has to do with the community of the + + + align:start position:0% +has to do with the community of the +Prisoners the solidarity and Community + + align:start position:0% +Prisoners the solidarity and Community + + + align:start position:0% +Prisoners the solidarity and Community +that's dramatized in the film in the end + + align:start position:0% +that's dramatized in the film in the end + + + align:start position:0% +that's dramatized in the film in the end +the duj character sacrifices himself for + + align:start position:0% +the duj character sacrifices himself for + + + align:start position:0% +the duj character sacrifices himself for +the good of the others something that we + + align:start position:0% +the good of the others something that we + + + align:start position:0% +the good of the others something that we +might find surprising at first given his + + align:start position:0% +might find surprising at first given his + + + align:start position:0% +might find surprising at first given his +distance from the other characters um um + + align:start position:0% +distance from the other characters um um + + + align:start position:0% +distance from the other characters um um +and uh there is a sense all the way + + align:start position:0% +and uh there is a sense all the way + + + align:start position:0% +and uh there is a sense all the way +through the film that the that that a + + align:start position:0% +through the film that the that that a + + + align:start position:0% +through the film that the that that a +kind of Comm + + align:start position:0% +kind of Comm + + + align:start position:0% +kind of Comm +or solidarity has been established + + align:start position:0% +or solidarity has been established + + + align:start position:0% +or solidarity has been established +amongst the men especially amongst the + + align:start position:0% +amongst the men especially amongst the + + + align:start position:0% +amongst the men especially amongst the +Frenchmen uh and especially that a kind + + align:start position:0% +Frenchmen uh and especially that a kind + + + align:start position:0% +Frenchmen uh and especially that a kind +of friendship between uh between + + align:start position:0% +of friendship between uh between + + + align:start position:0% +of friendship between uh between +rosental and Marell has been forged well + + align:start position:0% +rosental and Marell has been forged well + + + align:start position:0% +rosental and Marell has been forged well +again maybe that's a Grand Illusion the + + align:start position:0% +again maybe that's a Grand Illusion the + + + align:start position:0% +again maybe that's a Grand Illusion the +idea that you can transcend social class + + align:start position:0% +idea that you can transcend social class + + + align:start position:0% +idea that you can transcend social class +that you can transcend the uh ethnic uh + + align:start position:0% +that you can transcend the uh ethnic uh + + + align:start position:0% +that you can transcend the uh ethnic uh +prejudices into which you are born and + + align:start position:0% +prejudices into which you are born and + + + align:start position:0% +prejudices into which you are born and +and to which you've been uh um + + align:start position:0% +and to which you've been uh um + + + align:start position:0% +and to which you've been uh um +U with which you've been brainwashed so + + align:start position:0% +U with which you've been brainwashed so + + + align:start position:0% +U with which you've been brainwashed so +that's another kind kind of potential + + align:start position:0% +that's another kind kind of potential + + + align:start position:0% +that's another kind kind of potential +Grand Illusion and then finally the + + align:start position:0% +Grand Illusion and then finally the + + + align:start position:0% +Grand Illusion and then finally the +fourth example I would give the F the + + align:start position:0% +fourth example I would give the F the + + + align:start position:0% +fourth example I would give the F the +fourth Nuance that one could add to the + + align:start position:0% +fourth Nuance that one could add to the + + + align:start position:0% +fourth Nuance that one could add to the +title The Grand Illusion of movies + + align:start position:0% +title The Grand Illusion of movies + + + align:start position:0% +title The Grand Illusion of movies +themselves what are movies but Grand + + align:start position:0% +themselves what are movies but Grand + + + align:start position:0% +themselves what are movies but Grand +Illusions right they're + + align:start position:0% +Illusions right they're + + + align:start position:0% +Illusions right they're +two-dimensional not threedimensional but + + align:start position:0% +two-dimensional not threedimensional but + + + align:start position:0% +two-dimensional not threedimensional but +when we watch them we feel we've entered + + align:start position:0% +when we watch them we feel we've entered + + + align:start position:0% +when we watch them we feel we've entered +into a real world the Grand Illusion of + + align:start position:0% +into a real world the Grand Illusion of + + + align:start position:0% +into a real world the Grand Illusion of +movies themselves is part of what the + + align:start position:0% +movies themselves is part of what the + + + align:start position:0% +movies themselves is part of what the +title alludes to well something of the + + align:start position:0% +title alludes to well something of the + + + align:start position:0% +title alludes to well something of the +complexity and maturity of Renard vision + + align:start position:0% +complexity and maturity of Renard vision + + + align:start position:0% +complexity and maturity of Renard vision +of experience sense of human character + + align:start position:0% +of experience sense of human character + + + align:start position:0% +of experience sense of human character +and sense of history is embodied then in + + align:start position:0% +and sense of history is embodied then in + + + align:start position:0% +and sense of history is embodied then in +the complexity of the title of his + + align:start position:0% + + + + align:start position:0% + +movie \ No newline at end of file diff --git a/eRCN3daFCmU.txt b/eRCN3daFCmU.txt new file mode 100644 index 0000000000000000000000000000000000000000..5df605a054ed5374553f73fbf5a646db925ef447 --- /dev/null +++ b/eRCN3daFCmU.txt @@ -0,0 +1,2369 @@ +The following content is +provided under a Creative + +Commons license. + +Your support will help MIT +OpenCourseWare continue to + +offer high quality educational +resources for free. + +To make a donation or to view +additional materials from + +hundreds of MIT courses, visit +MIT OpenCourseWare at + +ocw.mit.edu. + +PROF. + +JERISON: So, we're ready to +begin Lecture 10, and what I'm + +going to begin with is +by finishing up some + +things from last time. + +We'll talk about approximations, +and I want to + +fill in a number of comments and +get you a little bit more + +oriented in the point of view +that I'm trying to express + +about approximations. + +So, first of all, I want to +remind you of the actual + +applied example that I +wrote down last time. + +So that was this +business here. + +There was something from +special relativity. + +And the approximation that +we used was the linear + +approximation, with a - 1/2 +power that comes out to be t( + +1 1/2 v^2 / C^2). + +I want to reiterate why +this is a useful way + +of thinking of things. + +And why this is that this +comes up in real life. + +Why this is maybe more important +than everything that + +I've taught you about +technically so far. + +So, first of all, what this is +telling us is the change in t + +/ t, if you do the arithmetic +here and subtract t that's + +using the change in +t is t' - t here. + +If you work that out, this is +approximately the same as 1/2 + +(v^2 / C^2). + +So what is this saying? + +This is saying that if you have +this satellite, which is + +going at speed v, and little c +is the speed of light, then + +the change in the watch down +here on earth, relative to the + +time on the satellite, is going +to be proportional to + +this ratio here. + +So, physically, this +makes sense. + +This is time divided by time. + +And this is velocity squared +divided by velocity squared. + +So, in each case, the +units divide out. + +So this is a dimensionless +quantity. + +And this is a dimensionless +quantity. + +And the only point here that +we're trying to make is just + +this notion of proportionality. + +So I want to write this down. + +Just, in summary. + +So the error fraction, if you +like, which is sort of the + +number of significant digits +that we have in our + +measurement, is proportional, +in this + +case, to this quantity. + +It happens to be proportional +to this quantity here. + +And the factor is, happens +to be, 1/2. + +So these proportionality +factors are what + +we're looking for. + +Their rates of change. + +Their rates of change of +something with respect to + +something else. + +Now, on your homework, +you have something + +rather similar to this. + +So in Problem, on Part 2b, Part +II, Problem 1, there's + +the speed of a pitch, right? + +And the speed of the pitch is +changing depending on how high + +the mound is. + +And the point here is that +that's approximately + +proportional to the change in +the height of the mound. + +In that problem, we had this +delta h, that was the x + +variable in that problem. + +And what you're trying to +figure out is what the + +constant of proportionality +is. + +That's what you're aiming +for in this problem. + +So there's a linear +relationship, approximately, + +to all intents and purposes +this is an equality. + +Because the lower +order terms are + +unimportant for the problem. + +Just as over here, this function +is a little bit + +complicated. + +This function is a little +more simple. + +For the purposes of this +problem, they are the same. + +Because the errors are +negligible for the particular + +problem that we're working on. + +So we might as well work with +the simpler relationship. + +And similarly, over here, so +you could do this with, in + +this case with square roots, +it's not so hard here with + +reciprocals of square roots. + +It's also not terribly hard +to do it numerically. + +And the reason why we're not +doing it numerically is that, + +as I say, this is something +that happens all across + +engineering. + +People are looking for these +linear relationships between + +the change in some input and +the change in the output. + +And if you don't make these +simplifications, then when you + +get, say, a dozen of them +together, you can't figure out + +what's going on. + +In this case the design of the + +satellite, it's very important. + +The speed actually isn't +just one speed. + +Because it's the relative speed +of u to the satellite. + +And you might be, it depends +on your angle of sight with + +the satellite what +the speed is. + +So it varies quite a bit. + +So you really need this +rule of thumb. + +Then there are all +kinds of other + +considerations in this question. + +Like, for example, there's the +fact that we're sitting on + +Earth and so we're rotating +around on what's called a + +non-inertial frame. + +So there's the question +of that acceleration. + +There's the question that the +gravity that I experience here + +on Earth is not the same +as up at the satellite. + +And that also creates a +difference in time, as a + +result of general relativity. + +So all of these considerations +come down to formulas which + +are this complicated or +maybe a tiny bit more. + +Not really that much. + +And then people simplify them +enormously to these very + +simple-minded rules. + +And they don't keep track +of what's going on. + +So in order to design the +system, you must make these + +simplifications, otherwise you +can't even think about + +what's going on. + +This comes up in everything. + +In weather forecasting, +economic forecasting. + +Figuring out whether there's +going to be an asteroid that's + +going to hit the Earth. + +Every single one of these things +involves dozens of + +these considerations. + +OK, there was a question +that I saw, here. + +Yes. + +STUDENT: [INAUDIBLE] + +PROF. + +JERISON: Yeah. + +Basically, any problem where +you have a derivative, the + +rate of change also depends upon +what the base point is. + +That's the question. + +You're saying, doesn't this +delta v also depend, I had a + +base point in that problem. + +I happened to decide that +pitchers pitch on average + +about 90 miles an hour. + +Whereas, in fact, some pitchers +pitch at 100 miles an + +hour, some pitch at 80 miles +an hour, and of course they + +vary the speed of the pitch. + +And so, this varies +a little bit. + +In fact, that's sort of +a second order effect. + +It does change the constant +of proportionality. + +It's a rate of change at +a different base point. + +Which we're considering fixed. + +In fact, that's sort of +a second order effect. + +When you actually do the +computations, what you + +discover is that it doesn't +make that much difference. + +To the a. + +And that's something that +you get from experience. + +That it turns out, which +things matter and + +which things don't. + +And yet again, that's exactly +the same sort of consideration + +but at the next order of what +I'm talking about here is. + +You have to have enough +experience with numbers to + +know that if you take, if you +vary something a little bit + +it's not going to change +the answer that you're + +looking for very much. + +And that's exactly the point +that I'm making. + +So I can't make them all at +once, all such points. + +So that's my pitch for +understanding things from this + +point of view. + +Now, we're going to go +on, now, to quadratic + +approximations, which are a +little more complicated. + +So, we talked a little bit about +this last time but I + +didn't finish. + +So I want to finish this up. + +And the first thing that I +should say is that you use the + +when the linear approximation +is not enough. + +OK, so, that's something that +you really need to get a + +little experience with. + +In economics, I told you they +use logarithms. So sometimes + +they use log linear functions. + +Sometimes they use log quadratic +functions when the + +log linear ones don't work. + +So most modeling in +economics is with + +log quadratic functions. + +And if you've made it +any more complicated + +than that, it's useless. + +And it's a mess. + +And people don't do it. + +So they stick with the quadratic +ones, typically. + +So the basic formula here, and +I'm going to take the base + +point to be 0, is that f ( +x ) is approximately f + +( 0 ) f' ( 0 )x. + +That's the linear part. + +Plus this extra term. + +Which is f'' ( 0 ) / 2x^2. + +And this is supposed to +work for x near 0. + +So it shows in the base point +as simply as possible. + +So here's more or less where +we left off last time. + +And one thing that I said I was +going to explain, which I + +will now, is why it's +(1/2) f'' ( 0 ). + +So we need to know that. + +So let's work that out +here first of all. + +So I'm just going to +do it by example. + +So if you like, the answer is +just, well, what happens when + +you have a parabola? + +A parabola's a quadratic. + +It had better, its quadratic +approximation + +had better be itself. + +It's got to be the best one. + +So it's got to be itself. + +So this formula, if it's +going to work, has + +to work on the nose. + +For quadratic functions. + +So, let's take a look. + +If I differentiate, +I get b 2cx. + +If I differentiate a second +time, I get 2c. + +And now let's plug it in. + +Well, we can recover, what is +it that we want to recover? + +We want to recover these numbers +a, b and c using the + +derivatives evaluated at 0. + +So let's see. + +It's pretty easy, actually. +f ( 0 ) = a. + +That's on the nose. + +If you plug in x = 0 here, +these terms drop + +out and you get a. + +And now, f' ( 0 ), whoops +that was wrong. + +So I wrote f' but what +I meant was f. + +So f ( 0 ) is a. + +Let's back up. f ( 0 ) is a, so +if I plug in x = 0 I get a. + +Now, f' ( 0 ), that's this next +formula here, f' ( 0 ), I + +plug in 0 here, and I get b. + +That's also good. + +And that's exactly what the +linear approximation is + +supposed to be. + +But now you notice, f'' is 2c. + +So to recover c, I better +take half of it. + +And that's it. + +That's the reason. + +There's no chance that any +other formula could work. + +And this one does. + +So that's the explanation +for the formula. + +And now I remind you that I +had a collection of basic + +formulas written on the board. + +And I want to just make sure +we know all of them again. + +So, first of all, there was +sine x is approximately x. + +Cosine x is approximately +1 - 1/2 x^2. + +And e ^ x is approximately +1 x 1/2 x^2. + +So those were three that +I mentioned last time. + +And, again, this is +all for x near 0. + +All for x near 0 only. + +These are wildly wrong, Far +away, but near 0 they're nice, + +good, quadratic approximations. + +Now, the other two +approximations that I want to + +mention are the logarithm and we +use the base point shifted. + +So we can put it at x near 0. + +And this one - sorry, +this is an + +approximately equals sign there. + +Turns out to be x - 1/2 x^2. + +And the last one is one (1 x) +^ r, which turns out to be 1 + +rx r ( r - 1) / 2x^2. + +Now, eventually, your mind will +converge on all of these + +and you'll find them relatively +easy to memorize. + +But it'll take some +getting used to. + +And I'm not claiming that you +should recognize them and + +understand them all now. + +But I'm going to put a giant +box around this. + +STUDENT: [INAUDIBLE] + +PROF. + +JERISON: Yes. + +So the question was, you get all +of these if you use that + +equation there. + +That's exactly what are you +going to do. so I already did + +it actually for these +three, last time. + +But I didn't do it yet +for these two. + +But I will do it in +about two minutes. + +Well, maybe five minutes. + +But first I want to explain just +a few things about these. + +They all follow from +the basic formula. + +In fact, that one deserves a +pink box too, doesn't it. + +That one's pretty important. + +Alright. + +Yeah. + +Maybe even some little +sparkles. + +Alright. + +OK. + +So that's pretty important. + +Almost as important as +the more basic one + +without this term here. + +So now, let me just tell you +a little bit more about the + +significance. + +Again, this is just to reinforce +something that we've + +already done. + +But it's closely related to +what you're doing on your + +problem set. + +So it's worth your while +to recall this. + +So, there's this expression +that we were dealing with. + +And we talked about +it in lecture. + +And we showed that this tends +to e as k goes to infinity. + +So that's what we showed +in lecture. + +And the way that we did that +was, we took the logarithm and + +we wrote it as k times, sorry, +the ln of 1 (1 / k). + +And then we evaluated +the limit of this. + +And I want to do this limit +again, using linear + +approximation. + +To show you how easy it is. + +If you just remember the +linear approximation. + +And then we'll explain +where the quadratic + +approximation comes in. + +So I claim that this +is approximately + +equal to k ( 1 / k). + +Now, why is that? + +Well, that's just this +linear approximation. + +So what did I use here? + +I used ln of 1 x is +approximately x. + +For x = 1 / k. + +That's what I used in this +approximation here. + +And that's the linear +approximation + +to the natural logarithm. + +And this number is relatively +easy to evaluate. + +I know how to do it. + +It's equal to 1. + +That's the same, well, so +where does this work? + +This works where this +thing is near 0. + +Which is when k is going +to infinity. + +This thing is working only when +k is going to infinity. + +So what it's really saying, this +approximation formula, + +it's really saying that as we +go to infinity, in k, this + +thing is going to 1. + +As k goes to infinity. + +So that's what it's saying. + +That's the substance there. + +And that's how we want to use +it, in many instances. + +Just to evaluate limits. + +We also want to realize that +it's nearby when k is pretty + +large, like 100 or something +like that. + +Now, so that's the idea of +the linear approximation. + +Now, if you want to get the rate +of convergence here, so + +the rate of what's called +convergence. + +So convergence means how fast +this is going towards that. + +What I have to do is take +the difference. + +I have to take ln ak, and I have +to subtract 1 from it. + +And I know that this is going to +0, and the question is how + +big is this. + +We want it to be very small. + +And the answer we're going to +get, so the answer just uses + +the quadratic approximation. + +So if I just have a little bit +more detail, then this + +expression here, in other words, +I have the next higher + +order term. + +This is like 1 / k, this +is like 1 / k^2. + +Then I can understand how big +the difference is between the + +expression that I've +got and its limit. + +And so that's what's +on your homework. + +This is on your problem set. + +OK, so that is more or less an +explanation for one of the + +things that quadratic +approximations are good for. + +And I'm going to give you +one more illustration. + +One more illustration. + +And then we'll actually +check these formulas. + +Yeah, another question. + +STUDENT: [INAUDIBLE] + +PROF. + +JERISON: That's a very +good question here. + +When they, which in this case +means maybe, me, when I give + +you a question, does one specify +whether you want to + +use a linear or a quadratic +approximation. + +The answer is, in real life +when you're faced with a + +problem like this, where some +satellite is orbiting and you + +want to know the effects of +gravity or something like + +that, nobody is going to +tell you anything. + +They're not even going to tell +you whether a linear + +approximation is relevant, or +a quadratic or anything. + +So you're on your own. + +When I give you a question, at +least for right now, I'm + +always going to tell you. + +But as time goes on I'd like you +to get used to when it's + +enough to get away with a +linear approximation. + +And you should only use a +quadratic approximation if + +somebody forces you to. + +You should always start trying +with a linear one. + +Because the quadratic ones are +much more complicated as + +you'll see in this +next example. + +OK, so the example that I want +to use is, you're going to be + +stuck with it because I'm asking +for the quadratic. + +So we're going to find the +quadratic approximation near, + +for x near 0. + +To what? + +Well, this is the same function +that we used in the + +last lecture. + +I think this was it. e +^ - 3x (1 x) ^ - 1/2. + +OK. + +So, unfortunately, I stuck it in +the wrong place to be able + +to fit this very long +formula here. + +So I'm going to switch it. + +I'm just going to +write it here. + +And we're going to just +do the approximation. + +So we're going to say quadratic, +in parentheses. + +And we'll say x near 0. + +So that's what I want. + +So now, here's what +I have to do. + +Well, I have to write in the +quadratic approximation for e + +^ - 3x, and I'm going to use +this formula right here. + +And so that's (1 (- +3x) (- 3x)^2 / 2). + +And the other factor, I'm going +to have to use this + +formula down here. because +r is - 1/2. + +And so that's (1 - 1/2 x 1/2 +( - 1/2)( - 3/2)x^2). + +So this is the r term, and +this is the r - 1 term. + +And now I'm going to do +something which is the only + +good thing about quadratic +approximations. + +They're messy, they're long, +there's nothing particularly + +good about them. + +But there is one good +thing about them. + +Which is that you always get +to ignore the higher order + +terms. So even though this +looks like a very ugly + +multiplication, I can +do it in my head. + +Just watching it. + +Because I get a 1 * 1, I'm +forced with that term here. + +And then I get the cross terms +which are linear, which is - + +3x - 1/2 x. + +We already did that when we +calculated the linear + +approximation, so that's +this times the 1 and + +this times that 1. + +And now I have three + +cross-terms which are quadratic. + +So one of them is these two +linear terms are multiplying. + +So that's plus 3/2 x^2. + +That's (- 3)( - 1/2). + +And then there's this term, +multiplying the 1, + +that's plus 9/2 x^2. + +And then there's one +last term, which is + +this monster here. + +Multiplying 1, and +that is - 3/8. + +So the great thing is, we drop +x^3, x ^ 4, etc., terms. Yeah? + +STUDENT: [INAUDIBLE] + +PROF. + +JERISON: OK, well +so copy it down. + +And you work it out as +I'm doing it now. + +So what I did is, I +multiplied 1 by 1. + +I'm using the distributive +law here. + +That was this one. + +I multiplied this 3x by this +one, that was that term. + +I multiplied this by this, +that's that term. + +And then I multiplied +this by this. + +In other words, 2 x terms +that gave me an x^2 + +and a (- 3)( - 1/2). + +And I'm going to stop +at that point. + +Because the point is it's +just all the rest of the + +terms that come up. + +Now, the reason, the only reason +why it's easy is that I + +only have to go up to +x squared term. + +I don't have to do +the higher ones. + +Another question, +way back here. + +Yeah, right there. + +STUDENT: [INAUDIBLE] + +PROF. + +JERISON: OK. + +So somebody can check +my arithmetic, too. + +Good. + +STUDENT: [INAUDIBLE] + +PROF. + +JERISON: Why do I get to drop +all the higher-order terms. + +So, that's because the situation +where I'm going to + +apply this is the situation +in which x is, say, 1/100. + +So if here's about 1/100. + +Here's something which is +on the order of 100. + +This is on the order +of 1/100^2. + +1/100^2, all of these terms. +Now, these cubic and quartic + +terms are of the order +of 1/100^3. + +That's 10 ^ - 6. + +And the point is that I'm +not claiming that I + +have an exact answer. + +And I'm going to drop things +of that order of magnitude. + +So I'm saving everything +up to 4 decimal places. + +I'm throwing away things which +are 6 decimal places out. + +Does that answer +your question? + +STUDENT: [INAUDIBLE] + +PROF. + +JERISON: So. + +That's the situation, and now +you can combine the terms. I + +mean, it's not very +impressive here. + +This is equal to 1 - 7/2 +x, maybe 51/8 x^2. + +If I've made that, if those +minus signs hadn't canceled, I + +would have gotten the +wrong answer here. + +Anyway. + +So, this is a 2 here, sorry. + +7/2. + +This is the linear approximation +we got last time + +and here's the extra information +that we got from + +this calculation. + +Which is this 51/8 term. + +Right, you have to accept that +there's a certain degree of + +complexity to this problem and +the answer is sufficiently + +complicated so it can't be less +arithmetic because we get + +this peculiar 51/8 +there, right. + +So one of the things to realize +is that these kinds of + +problems, because they involve +many, many terms are always + +going to involve a little bit +of complicated arithmetic. + +Last little bit, I did promise +you that I was going to derive + +these two relations, +as I said. + +Did the ones in the +left column. + +So let's carry that out. + +And as someone just pointed out, +it all comes from this + +formula here. + +So let's just check it. + +So we'll start with +the ln function. + +This is the function, f, +and then f' is 1/1 x. + +And f'', so this is f', this +is f'', is - 1/1 x^2. + +And now I have to +plug in x = 0. + +So at x = 0 this is +ln 1, which is 0. + +So this is at x = 0. + +I'm getting 0 here, I plug +in 0 and I get 1. + +And here, I plug in +0 and I get - 1. + +So now I go and I look up at +that formula, which is way in + +that upper corner there. + +And I see that the coefficient +on the constant is 0. + +The coefficient on x is 1. + +And then the other coefficient, +the very last + +one, is - 1/2. + +So this is the - 1 here. + +And then in the formula, +there's a 2 in the + +denominator. + +So it's half of whatever +I get for this second + +derivative, at 0. + +So this is the approximation +formula, which is way up in + +that corner there. + +Similarly, if I do it for +(1 x) ^ r, I have to + +differentiate that I get r( 1 +x) ^ r - 1, and then r ( r - + +1( x 1) ^ r - 2. + +So here are the derivatives. + +And so if I evaluate them +at x = 0, I get 1. + +That's 1 ^ r = 1. + +And here I get r. +(1 ^ r - 1)r. + +And here, I plug in x = 0 +and I get r ( r - 1). + +So again, the pattern is +right above it here. + +The 1 is there, the +r is there. + +And then instead of r ( r +- 1), I have half that. + +For the coefficient. + +So these are just examples. + +Obviously if we had a more +complicated functional, we + +might carry this out. + +But as a practical matter, we +try to stick with the ones in + +the pink box and just use +algebra to get other formulas. + +So I want to shift gears now and +treat the subject that was + +supposed to be this lecture. + +And we're not quite caught up, +but we will try to do our best + +to do as much as we can today. + +So the next topic is +curve sketching. + +And so let's get started +with that. + +So now, happily in this subject, +there are more + +pictures and it's a little +bit more geometric. + +And there's relatively +little computation. + +So let's hope we can do this. + +So I want to, so here +we go, we'll + +start with curve sketching. + +And the goal here + +STUDENT: [INAUDIBLE] + +PROF. + +JERISON: So that's like, +liner, the last time. + +That's kind of sketchy +spelling, isn't it? + +Yeah, there are certain kinds of +things which I can't spell. + +But, alright. + +Sketching. + +Alright. + +So here's our goal. + +Our goal is to draw the graph +of f, using f' and f''. + +Whether they're positive +or negative. + +So that's it. + +This is the goal here. + +However, there is a +big warning that I + +want to give you. + +And this is one that +unfortunately I now have to + +make you unlearn, especially +those that you that have + +actually had a little bit of +calculus before, I want to + +make you unlearn some of your +instincts that you developed. + +So this will be harder for those +of you who have actually + +done this before. + +But for the rest of you, it +will be relatively easy. + +Which is, don't abandon your +precalculus skills. + +And common sense. + +So there's a great deal of +common sense in this. + +And it actually trumps +some of the calculus. + +The calculus just fills +in what you + +didn't quite know yet. + +So I will try to illustrate +this. + +And because we're running a bit +late, I won't get to the + +some of the main punchlines +until next lecture. + +But I want you to do it. + +So for now, I'm just going to +tell you about the general + +principles. + +And in the process I'm going to +introduce the terminology. + +Just, the words that we need +to use to describe what is + +that we're doing. + +And there's also a certain +amount of carelessness with + +that in many of the treatments +that you'll see. + +And a lot of hastiness. + +So just be a little patient +and we will do this. + +So, the first principle +is the following. + +If f' is positive, then +f is increasing. + +That's a straightforward idea, +and it's closely related to + +this tangent line approximation +or the linear + +approximation that I just did. + +You can just imagine. + +Here's the tangent line, +here's the function. + +And if the tangent line is +pointing up, then the function + +is also going up, too. + +So that's all that's +going on here. + +Similarly, if f' is negative, +then f is decreasing. + +And that's the basic idea. + +Now, the second step is also +fairly straightforward. + +It's just a second order effect +of the same type. + +If you have f'' as positive, +then that means that f' is + +increasing. + +That's the same principle +applied one step up. + +Right? + +Because if f'' is positive, +that means it's the + +derivative of f'. + +So it's the same principle +just repeated. + +And now I just want to draw +a picture of this. + +Here's a picture +of it, I claim. + +And it looks like something's +going down. + +And I did that on purpose. + +But there is something that's +increasing here. + +Which is, the slope is very +steep negative here. + +And it's less steep negative +over here. + +So we have the slope which +is some negative + +number, say, - 4. + +And here it's - 3. + +So it's increasing. + +It's getting less negative, +and maybe eventually it'll + +curve up the other way. + +And this is a picture of what +I'm talking about here. + +That's what it means to say +that f' is increasing. + +The slope is getting larger. + +And the way to describe a curve +like this is that it's + +concave. So f is concave up. + +And similarly, f'' negative is +going to be the same thing as + +f concave, or implies +f concave down. + +So those are the ways in which +derivatives will help us + +qualitatively to draw graphs. + +But as I said before, we still +have to use a little bit of + +common sense when we +draw the graphs. + +These are just the additional +bits of help that + +we have from calculus. + +In drawing pictures. + +So I'm going to go through +one example to + +introduce all the notations. + +And then eventually, so probably +at the beginning of + +next time, I'll give you a +systematic strategy that's + +going to work when what I'm +describing now goes wrong, or + +a little bit wrong. + +So let's begin with a +straightforward example. + +So, the first example that I'll +give you is the function + +f (x) = 3x - x^3. + +Just, as I said, to be able to +introduce all the notations. + +Now, if you differentiate +it, you get 3 - 3x^2. + +And I can factor that. + +This is 3 ( 1 - x)( 1 x). + +OK? + +And so, I can decide whether +the derivative + +is positive or negative. + +Easily enough. + +Namely, just staring at this, +I can see that when -1 < x < + +1, in that range there, both +these numbers, both these + +factors, are positive. + +1 - x is a positive number and +1 x is a positive number. + +So, in this range, f' +( x ) is positive. + +So this thing is, so +f is increasing. + +And similarly, in the other +ranges, if x is very, very + +large, this becomes, if it +crosses 1, in fact, this + +becomes, this factor becomes +negative and + +this one stays positive. + +So when x > 1, we have that +f ' (x) is negative. + +And so f is decreasing. + +And the same thing goes +for the other side. + +When it's less than - 1, that +also works this way. + +Because when it's less +than - 1, this + +number factors positive. + +But the other one is negative. + +So in both of these cases, we +get that it's decreasing. + +So now, here's the schematic +picture of this function. + +So here's - 1, here's 1. + +It's going to go +down, up, down. + +That's what it's doing. + +Maybe I'll just leave +it alone like this. + +That's what it looks like. + +So, this is the kind of +information we can get right + +off the bat. + +And you notice immediately that +it's very important, from + +the features of the function, +the sort of key features of + +the function that we see here, +are these two places. + +Maybe I'll even mark them +in a, like this. + +And these things are +turning points. + +So what are they? + +Well, they're just the +points where the + +derivative changes sign. + +Where it's negative here and +it's positive there, so there + +it must be 0. + +So we have a definition, and +this is the most important + +definition in this subject, +which is that is if f' (x0) = + +0, we call x0 a critical +point. + +The word 'turning point' is +not used just because, in + +fact, it doesn't have to turn +around at those points. + +But certainly, if it turns +around then this will happen. + +And we also have another +notation, which is the number + +y0 which is f ( x0 ) is called +a critical value. + +So these are the key numbers +that we're going to have to + +work out in order to understand +what the function + +looks like. + +So what I'm going to do +is just plot them. + +We're going to plot +the critical + +points and the values. + +Well, we found the critical +points relatively easily. + +I didn't write it down here +but it's pretty obvious. + +If you set f(x) = 0, that +implies that (1 - x)( 1 x) = + +0, which implies that +x is or - 1. + +So those are known as +the critical points. + +And now, in order to get the +critical values here, I have + +to plug in f (1), for instance, +the function is 3x - + +x^2, so there's this 3 * +1 - 1^3, which is 2. + +And f ( - 1), which is 3 ( - +1) - (- 1)^3, which is - 2. + +And so I can plot the +function here. + +So here's the point - 1 and +here's, up here, is 2. + +So this is - whoops, +which one is it? + +Yeah. + +This is - 1, so it's +down here. + +So it's (- 1, - 2). + +And then over here, I have +the point (1, 2). + +Alright, now, what information +do I get from - so I've now + +plotted two, I claim, very +interesting points. + +What information do +I get from this? + +The answer is, I know something +very nearby. + +Because I've already checked +that the thing is coming down + +from the left, and +coming back up. + +And so it must be shaped +like this. + +Over here. + +The tangent line is 0, it's +going to be level there. + +And similarly over here, +it's going to do that. + +So this is what we know +so far, based + +on what we've computed. + +Question. + +STUDENT: [INAUDIBLE] + +PROF. + +JERISON: The question +is, what happens if + +there's a sharp corner. + +The answer is, calculus, it's +not called a critical point. + +It's a something else. + +And it's a very important +point, too. + +And we will be discussing +those kinds of points. + +There are much more dramatic +instances of that. + +That's part of what we're +going to say. + +But I just want to save +that, alright. + +We will be discussing. + +Yeah. + +Question. + +STUDENT: [INAUDIBLE] + +PROF. + +JERISON: The question that was +asked was, how did I know at + +the critical point that it's +concave down over here and + +concave up over here. + +The answer is that I actually +did not use the second + +derivative yet. + +What I used is another +piece of information. + +I used the information that +I derived over here. + +That f' is positive, where +f' is positive + +and where it's negative. + +So what I know is that the graph +is going down to the + +left of - 1. + +It's going up to the +right, here. + +It's going up here and it's +going down there. + +I did not use the second +derivative. + +I used the first derivative. + +OK, but I didn't just use the +fact that there was a turning + +point here. + +So, actually, I was using +the fact that it + +was a turning point. + +I wasn't using the fact +that it had the + +second derivative, though. + +OK. + +For now. + +You can also see it by the +second derivative as well. + +So now, the next thing that +I'd like to do, I need to + +finish off this graph. + +And I just want to do it a +little bit carefully here. + +In the order that +is reasonable. + +Now, you might happen to notice, +and there's nothing + +wrong with this, so let's +even fill in a guess. + +In order to fill in a guess, +though, and have it be even + +vaguely right, I do have to +notice that this thing + +crosses, this function +crosses the origin. + +The function f(x) = 3x - x^3 +happens also have the property + +that f ( 0 ) = 0. + +Again, common sense. + +You're allowed to use +your common sense. + +You're allowed to notice +a value of the + +function and put it in. + +So there's nothing +wrong with that. + +If you happen to have +such a value. + +So, now we can guess what +our function is + +going to look like. + +It's going to maybe come +down like this. + +Come up like this. + +And come down like this. + +That could be what +it looks like. + +But, you know, another +possibility is it sort of + +comes along here and +goes out that way. + +Comes along here and goes +out that way, who knows? + +It happens, by the way, that +it's an odd function. + +Right? + +Those are all odd powers. + +So, actually, it's symmetric +on the right half + +and the left half. + +And crosses at 0. + +So everything that we do on the +right is going to be the + +same as what happens +on the left. + +That's another piece +of common sense. + +You want to make use of that as +much as possible, whenever + +you're drawing anything. + +Don't want to throw +out information. + +So this function happens +to be odd. + +Odd, and f ( 0 ) = 0. + +I'm considering those to be +kinds of precalculus skills + +that I want you to use +as much as you can. + +So now, here's the first feature +which is unfortunately + +ignored in most discussions +of functions. + +And it's strange, because +nowadays we + +have graphing things. + +And it's really the only part +of the exercise that you + +couldn't do, at least on this +relatively simpleminded level, + +with a graphing calculator. + +And that is what I would call +the ends of the problem. + +So what happens off the screen, +is the question. + +And that basically is the +theoretical part of the + +problem that you have +to address. + +You can program this. + +You can draw all the pictures +that you want. + +But what you won't see is +what's off the screen. + +You need to know something +to figure out + +what's off the screen. + +So, in this case, I'm talking +about what's off the screen + +going to the right, or +going to the left. + +So let's check the ends. + +So here, let's just +take a look. + +We have the function f(x), which +is, sorry, 3x - x^3. + +Again this is a precalculus +sort of thing. + +And we're imagining now, +let's just do x + +goes to plus infinity. + +So what happens here. + +When x is gigantic, this term +is completely negligible. + +And it just behaves like - +x^3, which goes to minus + +infinity as x goes +to plus infinity. + +And similarly, f (x) goes to +plus infinity if x goes to + +minus infinity. + +Now let me pull down this +picture again, and show you + +what piece of the information +we've got. + +We now know that it is +heading up this way. + +It doesn't go like this, +it goes up like that. + +And I'm going to put an +arrow for it, And it's + +going down like this. + +Heading down to minus infinity +as x goes out + +farther to the right. + +And going out to plus infinity +as x goes farther to the left. + +So now there's hardly +anything left of + +this function to describe. + +There's really nothing left +except maybe decoration. + +And we kind of like that +decoration, so we will pay + +attention to it. + +And to do that, we'll have to +check the second derivative. + +So if we differentiate a +second time, the first + +derivative was, remember, +3 - 3x^2. + +So the second derivative +is - 6x. + +So now we notice that f'' (x) is +negative if x is positive. + +And f'' ( x) is positive +if x is negative. + +And so in this part +it's concave down. + +And in this part it's +concave up. + +And now I'm going to switch +the boards so that + +you'll, and draw it. + +And you see that it was begging +to be this way. + +So we'll fill in the +rest of it here. + +Maybe in a nice color here. + +So this is the whole graph and +this is the correct graph. + +It comes down in one swoop down +here, and comes up here. + +And then it changes to concave +down right at the origin. + +So this point is of interest, +not only because it's the + +place where it crosses the axis, +but it's also what's + +called an inflection point. + +Inflection point, that's a point +where because f'' at + +that place is equal to 0. + +So it's a place where the +second derivative is 0. + +We also consider those to +be interesting points. + +Now, so let me just making +one closing remark here. + +Which is that all of this +information fits together. + +And we're going to have much, +much harder examples of this + +where you'll actually have to +think about what's going on. + +But there's a lot of stuff +protecting you. + +And functions will behave +themselves and turn around + +appropriately. + +Anyway, we'll talk about +it next time. \ No newline at end of file diff --git a/ekgSqnLd0Ls.txt b/ekgSqnLd0Ls.txt new file mode 100644 index 0000000000000000000000000000000000000000..714303ae50fc3815d6784591c81cd01a108af550 --- /dev/null +++ b/ekgSqnLd0Ls.txt @@ -0,0 +1,11264 @@ +align:start position:0% + +hello everybody we're going to be + + align:start position:0% +hello everybody we're going to be + + + align:start position:0% +hello everybody we're going to be +looking today at how we can use machine + + align:start position:0% +looking today at how we can use machine + + + align:start position:0% +looking today at how we can use machine +learning and artificial intelligence in + + align:start position:0% +learning and artificial intelligence in + + + align:start position:0% +learning and artificial intelligence in +order to learn more about musical + + align:start position:0% +order to learn more about musical + + + align:start position:0% +order to learn more about musical +behavior and music theory and just music + + align:start position:0% +behavior and music theory and just music + + + align:start position:0% +behavior and music theory and just music +in general our first task is going to be + + align:start position:0% +in general our first task is going to be + + + align:start position:0% +in general our first task is going to be +how do we transform music into formats + + align:start position:0% +how do we transform music into formats + + + align:start position:0% +how do we transform music into formats +that computers can learn from because a + + align:start position:0% +that computers can learn from because a + + + align:start position:0% +that computers can learn from because a +score alone is not something that can be + + align:start position:0% +score alone is not something that can be + + + align:start position:0% +score alone is not something that can be +used for artificial intelligence and so + + align:start position:0% +used for artificial intelligence and so + + + align:start position:0% +used for artificial intelligence and so +our first task is going to be + + align:start position:0% +our first task is going to be + + + align:start position:0% +our first task is going to be +understanding how feature extraction the + + align:start position:0% +understanding how feature extraction the + + + align:start position:0% +understanding how feature extraction the +conversion of musical scores into + + align:start position:0% +conversion of musical scores into + + + align:start position:0% +conversion of musical scores into +intelligent numerical data how feature + + align:start position:0% +intelligent numerical data how feature + + + align:start position:0% +intelligent numerical data how feature +extraction is able to make machine + + align:start position:0% +extraction is able to make machine + + + align:start position:0% +extraction is able to make machine +learning possible so go ahead and load + + align:start position:0% +learning possible so go ahead and load + + + align:start position:0% +learning possible so go ahead and load +up juper notebook and follow along as we + + align:start position:0% +up juper notebook and follow along as we + + + align:start position:0% +up juper notebook and follow along as we +do some work with music 21 first + + align:start position:0% +do some work with music 21 first + + + align:start position:0% +do some work with music 21 first +separate from the music 21 machine + + align:start position:0% +separate from the music 21 machine + + + align:start position:0% +separate from the music 21 machine +learning tool kit and then with music 21 + + align:start position:0% +learning tool kit and then with music 21 + + + align:start position:0% +learning tool kit and then with music 21 +features in order to learn more about + + align:start position:0% +features in order to learn more about + + + align:start position:0% +features in order to learn more about +some genres and other ways of + + align:start position:0% +some genres and other ways of + + + align:start position:0% +some genres and other ways of +classifying + + align:start position:0% +classifying + + + align:start position:0% +classifying +music so go ahead and start Jupiter + + align:start position:0% +music so go ahead and start Jupiter + + + align:start position:0% +music so go ahead and start Jupiter +notebook and we're going to create uh + + align:start position:0% +notebook and we're going to create uh + + + align:start position:0% +notebook and we're going to create uh +the first step which is to understand + + align:start position:0% +the first step which is to understand + + + align:start position:0% +the first step which is to understand +what features are so I'll I know why we + + align:start position:0% +what features are so I'll I know why we + + + align:start position:0% +what features are so I'll I know why we +might want to extract them so what is a + + align:start position:0% +might want to extract them so what is a + + + align:start position:0% +might want to extract them so what is a +feature that's the first thing we're + + align:start position:0% +feature that's the first thing we're + + + align:start position:0% +feature that's the first thing we're +going to work on feature is something + + align:start position:0% +going to work on feature is something + + + align:start position:0% +going to work on feature is something +really really really basic let's say + + align:start position:0% +really really really basic let's say + + + align:start position:0% +really really really basic let's say +that we have a piece um will load from + + align:start position:0% +that we have a piece um will load from + + + align:start position:0% +that we have a piece um will load from +music 21 Corpus our favorite B Corral so + + align:start position:0% +music 21 Corpus our favorite B Corral so + + + align:start position:0% +music 21 Corpus our favorite B Corral so +you don't even need to know what comes + + align:start position:0% +you don't even need to know what comes + + + align:start position:0% +you don't even need to know what comes +up from this Corpus pars BL bwv 66. + + align:start position:0% +up from this Corpus pars BL bwv 66. + + + align:start position:0% +up from this Corpus pars BL bwv 66. +six and just to remind yourselves how it + + align:start position:0% +six and just to remind yourselves how it + + + align:start position:0% +six and just to remind yourselves how it +goes here's the + + align:start position:0% +goes here's the + + + align:start position:0% +goes here's the +buck so great let's go ahead + + align:start position:0% +buck so great let's go ahead + + + align:start position:0% +buck so great let's go ahead +and choose a feature from the this um + + align:start position:0% +and choose a feature from the this um + + + align:start position:0% +and choose a feature from the this um +from this let's do the parts feature and + + align:start position:0% +from this let's do the parts feature and + + + align:start position:0% +from this let's do the parts feature and +we'll call it num Parts equals 4 and + + align:start position:0% +we'll call it num Parts equals 4 and + + + align:start position:0% +we'll call it num Parts equals 4 and +let's do the time + + align:start position:0% +let's do the time + + + align:start position:0% +let's do the time +signature numerator + + align:start position:0% +signature numerator + + + align:start position:0% +signature numerator +feature equal + + align:start position:0% +feature equal + + + align:start position:0% +feature equal +4 there we've now extracted manually two + + align:start position:0% +4 there we've now extracted manually two + + + align:start position:0% +4 there we've now extracted manually two +features from this + + align:start position:0% +features from this + + + align:start position:0% +features from this +Coral feature extraction is the + + align:start position:0% +Coral feature extraction is the + + + align:start position:0% +Coral feature extraction is the +conversion of musical elements or any + + align:start position:0% +conversion of musical elements or any + + + align:start position:0% +conversion of musical elements or any +element but musical feature extraction + + align:start position:0% +element but musical feature extraction + + + align:start position:0% +element but musical feature extraction +is a conversion of musical elements into + + align:start position:0% +is a conversion of musical elements into + + + align:start position:0% +is a conversion of musical elements into +single numbers or lists arays vectors of + + align:start position:0% +single numbers or lists arays vectors of + + + align:start position:0% +single numbers or lists arays vectors of +numbers it is thus the most boring thing + + align:start position:0% +numbers it is thus the most boring thing + + + align:start position:0% +numbers it is thus the most boring thing +in the world as you've just + + align:start position:0% +in the world as you've just + + + align:start position:0% +in the world as you've just +seen it is just a bunch of numbers + + align:start position:0% +seen it is just a bunch of numbers + + + align:start position:0% +seen it is just a bunch of numbers +feature extraction sucks out the + + align:start position:0% +feature extraction sucks out the + + + align:start position:0% +feature extraction sucks out the +lifeblood of Music it takes everything + + align:start position:0% +lifeblood of Music it takes everything + + + align:start position:0% +lifeblood of Music it takes everything +that's beautiful in music and turns it + + align:start position:0% +that's beautiful in music and turns it + + + align:start position:0% +that's beautiful in music and turns it +into a bunch of numbers it is the life + + align:start position:0% +into a bunch of numbers it is the life + + + align:start position:0% +into a bunch of numbers it is the life +sucker it is the zombie of the musical + + align:start position:0% +sucker it is the zombie of the musical + + + align:start position:0% +sucker it is the zombie of the musical +world + + align:start position:0% +world + + + align:start position:0% +world +but but there are tons of amazing + + align:start position:0% +but but there are tons of amazing + + + align:start position:0% +but but there are tons of amazing +machine learning and artificial + + align:start position:0% +machine learning and artificial + + + align:start position:0% +machine learning and artificial +intelligence and deep learning + + align:start position:0% +intelligence and deep learning + + + align:start position:0% +intelligence and deep learning +algorithms in the world as far as I know + + align:start position:0% +algorithms in the world as far as I know + + + align:start position:0% +algorithms in the world as far as I know +they all have one thing in common they + + align:start position:0% +they all have one thing in common they + + + align:start position:0% +they all have one thing in common they +only work on collections of single + + align:start position:0% +only work on collections of single + + + align:start position:0% +only work on collections of single +numbers or vectors of + + align:start position:0% +numbers or vectors of + + + align:start position:0% +numbers or vectors of +numbers I'm not a machine learning + + align:start position:0% +numbers I'm not a machine learning + + + align:start position:0% +numbers I'm not a machine learning +expert so maybe there are algorithms + + align:start position:0% +expert so maybe there are algorithms + + + align:start position:0% +expert so maybe there are algorithms +that work on two or multi-dimensional + + align:start position:0% +that work on two or multi-dimensional + + + align:start position:0% +that work on two or multi-dimensional +arrays of numbers that would be amazing + + align:start position:0% +arrays of numbers that would be amazing + + + align:start position:0% +arrays of numbers that would be amazing +for Machine Vision or what we do but + + align:start position:0% +for Machine Vision or what we do but + + + align:start position:0% +for Machine Vision or what we do but +nothing as far as I know in the + + align:start position:0% +nothing as far as I know in the + + + align:start position:0% +nothing as far as I know in the +artificial intelligence World works on + + align:start position:0% +artificial intelligence World works on + + + align:start position:0% +artificial intelligence World works on +things + + align:start position:0% +things + + + align:start position:0% +things +like this + + align:start position:0% +like this + + + align:start position:0% +like this +notation or + + align:start position:0% +notation or + + + align:start position:0% +notation or +[Music] + + align:start position:0% + + + + align:start position:0% + +sound so if we're going to work on doing + + align:start position:0% +sound so if we're going to work on doing + + + align:start position:0% +sound so if we're going to work on doing +artificial intelligence or predictions + + align:start position:0% +artificial intelligence or predictions + + + align:start position:0% +artificial intelligence or predictions +or anything super amazing on music + + align:start position:0% +or anything super amazing on music + + + align:start position:0% +or anything super amazing on music +notation at least at present we need to + + align:start position:0% +notation at least at present we need to + + + align:start position:0% +notation at least at present we need to +convert music to + + align:start position:0% +convert music to + + + align:start position:0% +convert music to +numbers so that's what feature + + align:start position:0% +numbers so that's what feature + + + align:start position:0% +numbers so that's what feature +extraction is basic feature extraction + + align:start position:0% +extraction is basic feature extraction + + + align:start position:0% +extraction is basic feature extraction +is pretty + + align:start position:0% +is pretty + + + align:start position:0% +is pretty +simple so in this case let's just + + align:start position:0% +simple so in this case let's just + + + align:start position:0% +simple so in this case let's just +extract + + align:start position:0% +extract + + + align:start position:0% +extract +automatically the meter from this piece + + align:start position:0% +automatically the meter from this piece + + + align:start position:0% +automatically the meter from this piece +so we'll uh write something that does it + + align:start position:0% +so we'll uh write something that does it + + + align:start position:0% +so we'll uh write something that does it +we'll import from the typing module + + align:start position:0% +we'll import from the typing module + + + align:start position:0% +we'll import from the typing module +because we like to do things like this + + align:start position:0% +because we like to do things like this + + + align:start position:0% +because we like to do things like this +turn python which is a weakly typed + + align:start position:0% +turn python which is a weakly typed + + + align:start position:0% +turn python which is a weakly typed +language into slightly stronger typed so + + align:start position:0% +language into slightly stronger typed so + + + align:start position:0% +language into slightly stronger typed so +that we can um understand a little bit + + align:start position:0% +that we can um understand a little bit + + + align:start position:0% +that we can um understand a little bit +better um what's going to go on so we'll + + align:start position:0% +better um what's going to go on so we'll + + + align:start position:0% +better um what's going to go on so we'll +also import from music 21 the meter and + + align:start position:0% +also import from music 21 the meter and + + + align:start position:0% +also import from music 21 the meter and +stream modules now let's write something + + align:start position:0% +stream modules now let's write something + + + align:start position:0% +stream modules now let's write something +called + + align:start position:0% +called + + + align:start position:0% +called +extract extract meter which takes in a + + align:start position:0% +extract extract meter which takes in a + + + align:start position:0% +extract extract meter which takes in a +variable score which is a + + align:start position:0% +variable score which is a + + + align:start position:0% +variable score which is a +stream. stream object maybe it should be + + align:start position:0% +stream. stream object maybe it should be + + + align:start position:0% +stream. stream object maybe it should be +a stream. score object but let's keep it + + align:start position:0% +a stream. score object but let's keep it + + + align:start position:0% +a stream. score object but let's keep it +flexible and it returns a tupple of two + + align:start position:0% +flexible and it returns a tupple of two + + + align:start position:0% +flexible and it returns a tupple of two +integers and we'll say here that returns + + align:start position:0% +integers and we'll say here that returns + + + align:start position:0% +integers and we'll say here that returns +a two tle of the + + align:start position:0% +a two tle of the + + + align:start position:0% +a two tle of the +numerator and + + align:start position:0% +numerator and + + + align:start position:0% +numerator and +the + + align:start position:0% +the + + + align:start position:0% +the +denominator of the first time + + align:start position:0% + + + + align:start position:0% + +signature + + align:start position:0% +signature + + + align:start position:0% +signature +siger found in a + + align:start position:0% +siger found in a + + + align:start position:0% +siger found in a +score returns 0 comma 0 if the score has + + align:start position:0% +score returns 0 comma 0 if the score has + + + align:start position:0% +score returns 0 comma 0 if the score has +no meter why do we return 0 comma 0 if + + align:start position:0% +no meter why do we return 0 comma 0 if + + + align:start position:0% +no meter why do we return 0 comma 0 if +there's no meter in feature extraction + + align:start position:0% +there's no meter in feature extraction + + + align:start position:0% +there's no meter in feature extraction +it's generally assumed that we want to + + align:start position:0% +it's generally assumed that we want to + + + align:start position:0% +it's generally assumed that we want to +return out of bound number rather than + + align:start position:0% +return out of bound number rather than + + + align:start position:0% +return out of bound number rather than +raising exception if there's a + + align:start position:0% +raising exception if there's a + + + align:start position:0% +raising exception if there's a +mistake and the reason is you'd hate to + + align:start position:0% +mistake and the reason is you'd hate to + + + align:start position:0% +mistake and the reason is you'd hate to +be running extract meter on hundreds or + + align:start position:0% +be running extract meter on hundreds or + + + align:start position:0% +be running extract meter on hundreds or +thousands of pieces and you're always + + align:start position:0% +thousands of pieces and you're always + + + align:start position:0% +thousands of pieces and you're always +getting 4 comma 4 or 3 comma 4 or 6 + + align:start position:0% +getting 4 comma 4 or 3 comma 4 or 6 + + + align:start position:0% +getting 4 comma 4 or 3 comma 4 or 6 +comma 8 or even something wacky like 11 + + align:start position:0% +comma 8 or even something wacky like 11 + + + align:start position:0% +comma 8 or even something wacky like 11 +comma 32 and you it's all working + + align:start position:0% +comma 32 and you it's all working + + + align:start position:0% +comma 32 and you it's all working +successfully only to have your entire + + align:start position:0% +successfully only to have your entire + + + align:start position:0% +successfully only to have your entire +feature construction artificial + + align:start position:0% +feature construction artificial + + + align:start position:0% +feature construction artificial +intelligence pipeline fail if there's + + align:start position:0% +intelligence pipeline fail if there's + + + align:start position:0% +intelligence pipeline fail if there's +one piece that doesn't have a time + + align:start position:0% +one piece that doesn't have a time + + + align:start position:0% +one piece that doesn't have a time +signature like let's say it's Gregorian + + align:start position:0% +signature like let's say it's Gregorian + + + align:start position:0% +signature like let's say it's Gregorian +chant or some kind of trans + + align:start position:0% +chant or some kind of trans + + + align:start position:0% +chant or some kind of trans +meditation so that's why we're going to + + align:start position:0% +meditation so that's why we're going to + + + align:start position:0% +meditation so that's why we're going to +be putting returning 0 comma 0 on the + + align:start position:0% +be putting returning 0 comma 0 on the + + + align:start position:0% +be putting returning 0 comma 0 on the +other hand maybe it's a bad assumption + + align:start position:0% +other hand maybe it's a bad assumption + + + align:start position:0% +other hand maybe it's a bad assumption +and we should raise exceptions when + + align:start position:0% +and we should raise exceptions when + + + align:start position:0% +and we should raise exceptions when +something's not right and then we should + + align:start position:0% +something's not right and then we should + + + align:start position:0% +something's not right and then we should +fix our work rather than hiding + + align:start position:0% + + + + align:start position:0% + +errors but we'll get to that in just a + + align:start position:0% +errors but we'll get to that in just a + + + align:start position:0% +errors but we'll get to that in just a +bit first meter but first let's see how + + align:start position:0% +bit first meter but first let's see how + + + align:start position:0% +bit first meter but first let's see how +we do this so let's just remind + + align:start position:0% +we do this so let's just remind + + + align:start position:0% +we do this so let's just remind +ourselves we can take from anything get + + align:start position:0% +ourselves we can take from anything get + + + align:start position:0% +ourselves we can take from anything get +Elements by class meter. time + + align:start position:0% + + + + align:start position:0% + +signature and if we do not have the any + + align:start position:0% +signature and if we do not have the any + + + align:start position:0% +signature and if we do not have the any +the first meter will + + align:start position:0% +the first meter will + + + align:start position:0% +the first meter will +return 0 comma + + align:start position:0% +return 0 comma + + + align:start position:0% +return 0 comma +0 and otherwise we'll return the first + + align:start position:0% +0 and otherwise we'll return the first + + + align:start position:0% +0 and otherwise we'll return the first +meters numerator and the first + + align:start position:0% +meters numerator and the first + + + align:start position:0% +meters numerator and the first +meters + + align:start position:0% + + + + align:start position:0% + +denominator we're kind of hiding an + + align:start position:0% +denominator we're kind of hiding an + + + align:start position:0% +denominator we're kind of hiding an +error in our encoding um is that the + + align:start position:0% +error in our encoding um is that the + + + align:start position:0% +error in our encoding um is that the +right thing to do and I think this is + + align:start position:0% +right thing to do and I think this is + + + align:start position:0% +right thing to do and I think this is +something that when we're talking about + + align:start position:0% +something that when we're talking about + + + align:start position:0% +something that when we're talking about +it and I would love to talk to anybody + + align:start position:0% +it and I would love to talk to anybody + + + align:start position:0% +it and I would love to talk to anybody +directly about about ethics and morality + + align:start position:0% +directly about about ethics and morality + + + align:start position:0% +directly about about ethics and morality +and sort of what who artificial + + align:start position:0% +and sort of what who artificial + + + align:start position:0% +and sort of what who artificial +intelligence is working for because I + + align:start position:0% +intelligence is working for because I + + + align:start position:0% +intelligence is working for because I +think there are often important + + align:start position:0% +think there are often important + + + align:start position:0% +think there are often important +considerations of artificial + + align:start position:0% +considerations of artificial + + + align:start position:0% +considerations of artificial +intelligence with moral and ethical + + align:start position:0% +intelligence with moral and ethical + + + align:start position:0% +intelligence with moral and ethical +consequences when we hide things that it + + align:start position:0% +consequences when we hide things that it + + + align:start position:0% +consequences when we hide things that it +can't do and so I want you if you're + + align:start position:0% +can't do and so I want you if you're + + + align:start position:0% +can't do and so I want you if you're +going to be somebody who's going to be + + align:start position:0% +going to be somebody who's going to be + + + align:start position:0% +going to be somebody who's going to be +working with artificial intelligence and + + align:start position:0% +working with artificial intelligence and + + + align:start position:0% +working with artificial intelligence and +the rest of your life and Technology to + + align:start position:0% +the rest of your life and Technology to + + + align:start position:0% +the rest of your life and Technology to +think about such things maybe we + + align:start position:0% +think about such things maybe we + + + align:start position:0% +think about such things maybe we +shouldn't be hiding our error so + + align:start position:0% +shouldn't be hiding our error so + + + align:start position:0% +shouldn't be hiding our error so +much okay so we have this extract meter + + align:start position:0% +much okay so we have this extract meter + + + align:start position:0% +much okay so we have this extract meter +to get back to this whoops um doesn't + + align:start position:0% +to get back to this whoops um doesn't + + + align:start position:0% +to get back to this whoops um doesn't +matter if you put a parenthesis around a + + align:start position:0% +matter if you put a parenthesis around a + + + align:start position:0% +matter if you put a parenthesis around a +tupple when you return it but if you + + align:start position:0% +tupple when you return it but if you + + + align:start position:0% +tupple when you return it but if you +start with one you have to do the other + + align:start position:0% +start with one you have to do the other + + + align:start position:0% +start with one you have to do the other +okay so let's take this B Corral and + + align:start position:0% +okay so let's take this B Corral and + + + align:start position:0% +okay so let's take this B Corral and +let's run extract + + align:start position:0% +let's run extract + + + align:start position:0% +let's run extract +meter on the B + + align:start position:0% +meter on the B + + + align:start position:0% +meter on the B +oh0 comma 0 oh I know why because we + + align:start position:0% +oh0 comma 0 oh I know why because we + + + align:start position:0% +oh0 comma 0 oh I know why because we +forgot to do + + align:start position:0% +forgot to do + + + align:start position:0% +forgot to do +recurse you know flat would do just as + + align:start position:0% +recurse you know flat would do just as + + + align:start position:0% +recurse you know flat would do just as +well but recurse is a little bit faster + + align:start position:0% +well but recurse is a little bit faster + + + align:start position:0% +well but recurse is a little bit faster +and oh by the way something I didn't + + align:start position:0% +and oh by the way something I didn't + + + align:start position:0% +and oh by the way something I didn't +mention uh you might have seen that + + align:start position:0% +mention uh you might have seen that + + + align:start position:0% +mention uh you might have seen that +we're sending in the class actual class + + align:start position:0% +we're sending in the class actual class + + + align:start position:0% +we're sending in the class actual class +meter. time signature we could also put + + align:start position:0% +meter. time signature we could also put + + + align:start position:0% +meter. time signature we could also put +in the um strin time signature doesn't + + align:start position:0% +in the um strin time signature doesn't + + + align:start position:0% +in the um strin time signature doesn't +matter either way there um but this + + align:start position:0% +matter either way there um but this + + + align:start position:0% +matter either way there um but this +actually doesn't get us the first meter + + align:start position:0% +actually doesn't get us the first meter + + + align:start position:0% +actually doesn't get us the first meter +this gets us all the meters and so if + + align:start position:0% +this gets us all the meters and so if + + + align:start position:0% +this gets us all the meters and so if +there are no + + align:start position:0% +there are no + + + align:start position:0% +there are no +meters that says if there's not a single + + align:start position:0% +meters that says if there's not a single + + + align:start position:0% +meters that says if there's not a single +one return that we'll call First + + align:start position:0% +one return that we'll call First + + + align:start position:0% +one return that we'll call First +meter the first of all meters so of + + align:start position:0% +meter the first of all meters so of + + + align:start position:0% +meter the first of all meters so of +course it's number zero now that's + + align:start position:0% +course it's number zero now that's + + + align:start position:0% +course it's number zero now that's +should be there now extract meter Bo + + align:start position:0% +should be there now extract meter Bo + + + align:start position:0% +should be there now extract meter Bo +fantastic returns four comma + + align:start position:0% +fantastic returns four comma + + + align:start position:0% +fantastic returns four comma +4 so why would we want to extract the + + align:start position:0% +4 so why would we want to extract the + + + align:start position:0% +4 so why would we want to extract the +meter as two numbers as part of future + + align:start position:0% +meter as two numbers as part of future + + + align:start position:0% +meter as two numbers as part of future +extraction we might do it as part of a + + align:start position:0% +extraction we might do it as part of a + + + align:start position:0% +extraction we might do it as part of a +series of features in order to make a + + align:start position:0% +series of features in order to make a + + + align:start position:0% +series of features in order to make a +prediction about a piece let's say we + + align:start position:0% +prediction about a piece let's say we + + + align:start position:0% +prediction about a piece let's say we +wanted to predict if a piece of music is + + align:start position:0% +wanted to predict if a piece of music is + + + align:start position:0% +wanted to predict if a piece of music is +a waltz or not so we might first think + + align:start position:0% +a waltz or not so we might first think + + + align:start position:0% +a waltz or not so we might first think +is this a + + align:start position:0% + + + + align:start position:0% + +waltz or is this a Walts + + align:start position:0% +waltz or is this a Walts + + + align:start position:0% +waltz or is this a Walts +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +is this a + + align:start position:0% + + + + align:start position:0% + +Walts so what makes something a Walts + + align:start position:0% +Walts so what makes something a Walts + + + align:start position:0% +Walts so what makes something a Walts +well it probably has something to do + + align:start position:0% +well it probably has something to do + + + align:start position:0% +well it probably has something to do +with a meter we fortunately already have + + align:start position:0% +with a meter we fortunately already have + + + align:start position:0% +with a meter we fortunately already have +a meter extraction for types cure for + + align:start position:0% +a meter extraction for types cure for + + + align:start position:0% +a meter extraction for types cure for +the piece and now we can use this to try + + align:start position:0% +the piece and now we can use this to try + + + align:start position:0% +the piece and now we can use this to try +to figure out if something is a Walter + + align:start position:0% +to figure out if something is a Walter + + + align:start position:0% +to figure out if something is a Walter +not so we would assume that the + + align:start position:0% +not so we would assume that the + + + align:start position:0% +not so we would assume that the +prevailing time signature in a piece and + + align:start position:0% +prevailing time signature in a piece and + + + align:start position:0% +prevailing time signature in a piece and +the opening time signature in a piece if + + align:start position:0% +the opening time signature in a piece if + + + align:start position:0% +the opening time signature in a piece if +it's a Walt would be 34 and therefore + + align:start position:0% +it's a Walt would be 34 and therefore + + + align:start position:0% +it's a Walt would be 34 and therefore +our extraction should be 3 comma + + align:start position:0% +our extraction should be 3 comma + + + align:start position:0% +our extraction should be 3 comma +4 that is the worst assumption ever the + + align:start position:0% +4 that is the worst assumption ever the + + + align:start position:0% +4 that is the worst assumption ever the +most famous Walts of all time Johan + + align:start position:0% +most famous Walts of all time Johan + + + align:start position:0% +most famous Walts of all time Johan +truss's blue Dan Waltz which you just + + align:start position:0% +truss's blue Dan Waltz which you just + + + align:start position:0% +truss's blue Dan Waltz which you just +heard doesn't start in 34 it starts with + + align:start position:0% +heard doesn't start in 34 it starts with + + + align:start position:0% +heard doesn't start in 34 it starts with +a slow introduction in 68 + + align:start position:0% + + + + align:start position:0% + +time I happen to have a random Waltz on + + align:start position:0% +time I happen to have a random Waltz on + + + align:start position:0% +time I happen to have a random Waltz on +my computer it's Yan strauss's Waltz + + align:start position:0% +my computer it's Yan strauss's Waltz + + + align:start position:0% +my computer it's Yan strauss's Waltz +called on the blue denu it's not in the + + align:start position:0% +called on the blue denu it's not in the + + + align:start position:0% +called on the blue denu it's not in the +music 21 Corpus but it's instead on my + + align:start position:0% +music 21 Corpus but it's instead on my + + + align:start position:0% +music 21 Corpus but it's instead on my +hard drive on my desktop so I'll need to + + align:start position:0% +hard drive on my desktop so I'll need to + + + align:start position:0% +hard drive on my desktop so I'll need to +import the converter module from music + + align:start position:0% +import the converter module from music + + + align:start position:0% +import the converter module from music +21 I mean it's just a wrapper around + + align:start position:0% +21 I mean it's just a wrapper around + + + align:start position:0% +21 I mean it's just a wrapper around +loading things and stuff and now instead + + align:start position:0% +loading things and stuff and now instead + + + align:start position:0% +loading things and stuff and now instead +of using Corpus parse I'll use converter + + align:start position:0% +of using Corpus parse I'll use converter + + + align:start position:0% +of using Corpus parse I'll use converter +dopar I'll give um the full file name to + + align:start position:0% +dopar I'll give um the full file name to + + + align:start position:0% +dopar I'll give um the full file name to +file path to my um to my + + align:start position:0% +file path to my um to my + + + align:start position:0% +file path to my um to my +Walts it's a music XML + + align:start position:0% + + + + align:start position:0% + +file oh great so the guy who's making + + align:start position:0% +file oh great so the guy who's making + + + align:start position:0% +file oh great so the guy who's making +this recording just goes online grabs a + + align:start position:0% +this recording just goes online grabs a + + + align:start position:0% +this recording just goes online grabs a +random music XML copy of the blue danu + + align:start position:0% +random music XML copy of the blue danu + + + align:start position:0% +random music XML copy of the blue danu +from the + + align:start position:0% +from the + + + align:start position:0% +from the +internet and this version skips the + + align:start position:0% +internet and this version skips the + + + align:start position:0% +internet and this version skips the +introduction completely so it has 34 + + align:start position:0% +introduction completely so it has 34 + + + align:start position:0% +introduction completely so it has 34 +when it should have gotten 68 so it's + + align:start position:0% +when it should have gotten 68 so it's + + + align:start position:0% +when it should have gotten 68 so it's +going to get the right answer but for + + align:start position:0% +going to get the right answer but for + + + align:start position:0% +going to get the right answer but for +all the wrong reasons have you ever + + align:start position:0% +all the wrong reasons have you ever + + + align:start position:0% +all the wrong reasons have you ever +heard the expression goo garbage in + + align:start position:0% +heard the expression goo garbage in + + + align:start position:0% +heard the expression goo garbage in +equals garbage + + align:start position:0% +equals garbage + + + align:start position:0% +equals garbage +out let's not do that in our own work + + align:start position:0% +out let's not do that in our own work + + + align:start position:0% +out let's not do that in our own work +what we're learning from in this + + align:start position:0% +what we're learning from in this + + + align:start position:0% +what we're learning from in this +tutorial let's instead make the world of + + align:start position:0% +tutorial let's instead make the world of + + + align:start position:0% +tutorial let's instead make the world of +artificial intelligence a better place + + align:start position:0% +artificial intelligence a better place + + + align:start position:0% +artificial intelligence a better place +and always check whether our training + + align:start position:0% +and always check whether our training + + + align:start position:0% +and always check whether our training +data is correct whether this is actually + + align:start position:0% +data is correct whether this is actually + + + align:start position:0% +data is correct whether this is actually +a score of the Blue danu rather than + + align:start position:0% +a score of the Blue danu rather than + + + align:start position:0% +a score of the Blue danu rather than +just the main theme of it let's check + + align:start position:0% +just the main theme of it let's check + + + align:start position:0% +just the main theme of it let's check +things like this before we use + + align:start position:0% + + + + align:start position:0% + +it great so it's in 34 so our extract + + align:start position:0% +it great so it's in 34 so our extract + + + align:start position:0% +it great so it's in 34 so our extract +meter function is going to return 34 + + align:start position:0% +meter function is going to return 34 + + + align:start position:0% +meter function is going to return 34 +let's try that + + align:start position:0% + + + + align:start position:0% + +oops sorry don't give the answer give + + align:start position:0% +oops sorry don't give the answer give + + + align:start position:0% +oops sorry don't give the answer give +the question there we go so now we have + + align:start position:0% +the question there we go so now we have + + + align:start position:0% +the question there we go so now we have +our first feature that might help + + align:start position:0% +our first feature that might help + + + align:start position:0% +our first feature that might help +identify a Walt it's Tim + + align:start position:0% +identify a Walt it's Tim + + + align:start position:0% +identify a Walt it's Tim +signature now let's do something a + + align:start position:0% +signature now let's do something a + + + align:start position:0% +signature now let's do something a +little bit more advanced and let's let's + + align:start position:0% +little bit more advanced and let's let's + + + align:start position:0% +little bit more advanced and let's let's +look at this piece and see H is there + + align:start position:0% +look at this piece and see H is there + + + align:start position:0% +look at this piece and see H is there +anything that seems to happen pretty + + align:start position:0% +anything that seems to happen pretty + + + align:start position:0% +anything that seems to happen pretty +often well it looks like the last beat + + align:start position:0% +often well it looks like the last beat + + + align:start position:0% +often well it looks like the last beat +beat three of the piece or offset two is + + align:start position:0% +beat three of the piece or offset two is + + + align:start position:0% +beat three of the piece or offset two is +more often higher than offset one I + + align:start position:0% +more often higher than offset one I + + + align:start position:0% +more often higher than offset one I +don't know if that's true but that that + + align:start position:0% +don't know if that's true but that that + + + align:start position:0% +don't know if that's true but that that +looks like something that's a + + align:start position:0% +looks like something that's a + + + align:start position:0% +looks like something that's a +possibility so we'll create sort of a + + align:start position:0% +possibility so we'll create sort of a + + + align:start position:0% +possibility so we'll create sort of a +more sophisticated feature extractor + + align:start position:0% +more sophisticated feature extractor + + + align:start position:0% +more sophisticated feature extractor +which uh Returns the proportion of all + + align:start position:0% +which uh Returns the proportion of all + + + align:start position:0% +which uh Returns the proportion of all +the measures where beat 3 is above beat + + align:start position:0% +the measures where beat 3 is above beat + + + align:start position:0% +the measures where beat 3 is above beat +1 first we'll make the assumption that + + align:start position:0% +1 first we'll make the assumption that + + + align:start position:0% +1 first we'll make the assumption that +beat 1 is always at offset zero and beat + + align:start position:0% +beat 1 is always at offset zero and beat + + + align:start position:0% +beat 1 is always at offset zero and beat +3 is at offset to these aren't very good + + align:start position:0% +3 is at offset to these aren't very good + + + align:start position:0% +3 is at offset to these aren't very good +assumptions uh but maybe together with + + align:start position:0% +assumptions uh but maybe together with + + + align:start position:0% +assumptions uh but maybe together with +searching for meter they'll too will + + align:start position:0% +searching for meter they'll too will + + + align:start position:0% +searching for meter they'll too will +make a good case for whether something + + align:start position:0% +make a good case for whether something + + + align:start position:0% +make a good case for whether something +is a waltz or not so here we go uh if + + align:start position:0% +is a waltz or not so here we go uh if + + + align:start position:0% +is a waltz or not so here we go uh if +we're going to we're going to eventually + + align:start position:0% +we're going to we're going to eventually + + + align:start position:0% +we're going to we're going to eventually +write something uh proportion uh prop + + align:start position:0% +write something uh proportion uh prop + + + align:start position:0% +write something uh proportion uh prop +proportion of + + align:start position:0% + + + + align:start position:0% + +bat3 above beat one which is going to + + align:start position:0% +bat3 above beat one which is going to + + + align:start position:0% +bat3 above beat one which is going to +take a score stream stream and it's + + align:start position:0% +take a score stream stream and it's + + + align:start position:0% +take a score stream stream and it's +going to return a float because it's a + + align:start position:0% +going to return a float because it's a + + + align:start position:0% +going to return a float because it's a +proportion and I'll just say pass now + + align:start position:0% +proportion and I'll just say pass now + + + align:start position:0% +proportion and I'll just say pass now +because in order to write this of of + + align:start position:0% +because in order to write this of of + + + align:start position:0% +because in order to write this of of +course uh we're going to need something + + align:start position:0% +course uh we're going to need something + + + align:start position:0% +course uh we're going to need something +that figures out for any given measure + + align:start position:0% +that figures out for any given measure + + + align:start position:0% +that figures out for any given measure +if beat 3 is above beat + + align:start position:0% +if beat 3 is above beat + + + align:start position:0% +if beat 3 is above beat +one for a single measure for one measure + + align:start position:0% +one for a single measure for one measure + + + align:start position:0% +one for a single measure for one measure +so we'll take an M which will be a + + align:start position:0% +so we'll take an M which will be a + + + align:start position:0% +so we'll take an M which will be a +stream. measure and this is going to + + align:start position:0% +stream. measure and this is going to + + + align:start position:0% +stream. measure and this is going to +return true or false oops it's going to + + align:start position:0% +return true or false oops it's going to + + + align:start position:0% +return true or false oops it's going to +return true or false someday we going to + + align:start position:0% +return true or false someday we going to + + + align:start position:0% +return true or false someday we going to +have an incredible production crew + + align:start position:0% +have an incredible production crew + + + align:start position:0% +have an incredible production crew +that's going to edit out all these + + align:start position:0% +that's going to edit out all these + + + align:start position:0% +that's going to edit out all these +mistakes but I don't have that yet so + + align:start position:0% +mistakes but I don't have that yet so + + + align:start position:0% +mistakes but I don't have that yet so +we'll say that measures notes are get + + align:start position:0% +we'll say that measures notes are get + + + align:start position:0% +we'll say that measures notes are get +all the elements by class note and that + + align:start position:0% +all the elements by class note and that + + + align:start position:0% +all the elements by class note and that +returns this stream iterator for now I'm + + align:start position:0% +returns this stream iterator for now I'm + + + align:start position:0% +returns this stream iterator for now I'm +going to say recast that stream iterator + + align:start position:0% +going to say recast that stream iterator + + + align:start position:0% +going to say recast that stream iterator +as another stream uh you can do this + + align:start position:0% +as another stream uh you can do this + + + align:start position:0% +as another stream uh you can do this +with any of the get something bu + + align:start position:0% +with any of the get something bu + + + align:start position:0% +with any of the get something bu +something uh classes in music 21 great + + align:start position:0% +something uh classes in music 21 great + + + align:start position:0% +something uh classes in music 21 great +so within this is now a stream of just + + align:start position:0% +so within this is now a stream of just + + + align:start position:0% +so within this is now a stream of just +nothing but notes and so I can say the + + align:start position:0% +nothing but notes and so I can say the + + + align:start position:0% +nothing but notes and so I can say the +first notes are those notes + + align:start position:0% +first notes are those notes + + + align:start position:0% +first notes are those notes +that appear at an offset + + align:start position:0% +that appear at an offset + + + align:start position:0% +that appear at an offset +zero and if there's no note there return + + align:start position:0% +zero and if there's no note there return + + + align:start position:0% +zero and if there's no note there return +fulse great now we'll check bat3 notes + + align:start position:0% +fulse great now we'll check bat3 notes + + + align:start position:0% +fulse great now we'll check bat3 notes +are those + + align:start position:0% +are those + + + align:start position:0% +are those +notes + + align:start position:0% +notes + + + align:start position:0% +notes +that are at offset 2 and that began at + + align:start position:0% +that are at offset 2 and that began at + + + align:start position:0% +that are at offset 2 and that began at +offset 2 so that should work pretty well + + align:start position:0% +offset 2 so that should work pretty well + + + align:start position:0% +offset 2 so that should work pretty well +and if there's no note + + align:start position:0% +and if there's no note + + + align:start position:0% +and if there's no note +that satisfies that + + align:start position:0% + + + + align:start position:0% + +condition we're going to return false + + align:start position:0% +condition we're going to return false + + + align:start position:0% +condition we're going to return false +again but what if there is more than one + + align:start position:0% +again but what if there is more than one + + + align:start position:0% +again but what if there is more than one +note at the beginning of the measure or + + align:start position:0% +note at the beginning of the measure or + + + align:start position:0% +note at the beginning of the measure or +at + + align:start position:0% +at + + + align:start position:0% +at +bat3 so we have to make sure that first + + align:start position:0% +bat3 so we have to make sure that first + + + align:start position:0% +bat3 so we have to make sure that first +note is the first of the beat3 + + align:start position:0% +note is the first of the beat3 + + + align:start position:0% +note is the first of the beat3 +notes and the beat3 note not is the + + align:start position:0% +notes and the beat3 note not is the + + + align:start position:0% +notes and the beat3 note not is the +first of the beat3 notes not the third + + align:start position:0% +first of the beat3 notes not the third + + + align:start position:0% +first of the beat3 notes not the third +the first now we'll go ahead and say if + + align:start position:0% +the first now we'll go ahead and say if + + + align:start position:0% +the first now we'll go ahead and say if +the first note pitch is lower and we're + + align:start position:0% +the first note pitch is lower and we're + + + align:start position:0% +the first note pitch is lower and we're +going to measure the pitch by pitch + + align:start position:0% +going to measure the pitch by pitch + + + align:start position:0% +going to measure the pitch by pitch +space or midi number uh is less than the + + align:start position:0% +space or midi number uh is less than the + + + align:start position:0% +space or midi number uh is less than the +beat3 + + align:start position:0% +beat3 + + + align:start position:0% +beat3 +notes pit space will return false + + align:start position:0% +notes pit space will return false + + + align:start position:0% +notes pit space will return false +otherwise we're going to return true + + align:start position:0% +otherwise we're going to return true + + + align:start position:0% +otherwise we're going to return true +um great we'll let's be good we'll make + + align:start position:0% +um great we'll let's be good we'll make + + + align:start position:0% +um great we'll let's be good we'll make +this a second thing we'll put cut and + + align:start position:0% +this a second thing we'll put cut and + + + align:start position:0% +this a second thing we'll put cut and +paste that there Meanwhile we're going + + align:start position:0% +paste that there Meanwhile we're going + + + align:start position:0% +paste that there Meanwhile we're going +to um let's write a little test on this + + align:start position:0% +to um let's write a little test on this + + + align:start position:0% +to um let's write a little test on this +so we have blue um let's get measure + + align:start position:0% +so we have blue um let's get measure + + + align:start position:0% +so we have blue um let's get measure +zero so + + align:start position:0% +zero so + + + align:start position:0% +zero so +m0 actually it's measure one so blue. + + align:start position:0% +m0 actually it's measure one so blue. + + + align:start position:0% +m0 actually it's measure one so blue. +measure one and we'll + + align:start position:0% +measure one and we'll + + + align:start position:0% +measure one and we'll +see is + + align:start position:0% +see is + + + align:start position:0% +see is +beat3 above beat 1 + + align:start position:0% + + + + align:start position:0% + +oops + + align:start position:0% + + + + align:start position:0% + +little elements + + align:start position:0% +little elements + + + align:start position:0% +little elements +you so this + + align:start position:0% +you so this + + + align:start position:0% +you so this +fight this is why we test things great + + align:start position:0% +fight this is why we test things great + + + align:start position:0% +fight this is why we test things great +is beat three above beat one in + + align:start position:0% +is beat three above beat one in + + + align:start position:0% +is beat three above beat one in +measure one actually is + + align:start position:0% +measure one actually is + + + align:start position:0% +measure one actually is +huh oh I know what it is we have a + + align:start position:0% +huh oh I know what it is we have a + + + align:start position:0% +huh oh I know what it is we have a +reverse of a sign it if this pitch is + + align:start position:0% +reverse of a sign it if this pitch is + + + align:start position:0% +reverse of a sign it if this pitch is +greater than or equal then we returned + + align:start position:0% +greater than or equal then we returned + + + align:start position:0% +greater than or equal then we returned +false actually if it's yeah the equal + + align:start position:0% +false actually if it's yeah the equal + + + align:start position:0% +false actually if it's yeah the equal +sign there and now that's working + + align:start position:0% +sign there and now that's working + + + align:start position:0% +sign there and now that's working +measure two should be true also measure + + align:start position:0% +measure two should be true also measure + + + align:start position:0% +measure two should be true also measure +three should be false let's make sure + + align:start position:0% +three should be false let's make sure + + + align:start position:0% +three should be false let's make sure +that + + align:start position:0% +that + + + align:start position:0% +that +works yep and false great so that seems + + align:start position:0% +works yep and false great so that seems + + + align:start position:0% +works yep and false great so that seems +to be working um here's the irony uh + + align:start position:0% +to be working um here's the irony uh + + + align:start position:0% +to be working um here's the irony uh +actually except for the fact that our + + align:start position:0% +actually except for the fact that our + + + align:start position:0% +actually except for the fact that our +label would be completely wrong uh + + align:start position:0% +label would be completely wrong uh + + + align:start position:0% +label would be completely wrong uh +having every single thing that should be + + align:start position:0% +having every single thing that should be + + + align:start position:0% +having every single thing that should be +false be true and true be false probably + + align:start position:0% +false be true and true be false probably + + + align:start position:0% +false be true and true be false probably +wouldn't change our answers very much + + align:start position:0% +wouldn't change our answers very much + + + align:start position:0% +wouldn't change our answers very much +but who knows we call this is beat three + + align:start position:0% +but who knows we call this is beat three + + + align:start position:0% +but who knows we call this is beat three +above beat one in one + + align:start position:0% +above beat one in one + + + align:start position:0% +above beat one in one +measure it better do what it says okay + + align:start position:0% +measure it better do what it says okay + + + align:start position:0% +measure it better do what it says okay +great now we're going to get the + + align:start position:0% +great now we're going to get the + + + align:start position:0% +great now we're going to get the +proportion that is U the proportion of + + align:start position:0% +proportion that is U the proportion of + + + align:start position:0% +proportion that is U the proportion of +measures in this piece where B3 is above + + align:start position:0% +measures in this piece where B3 is above + + + align:start position:0% +measures in this piece where B3 is above +B1 so + + align:start position:0% +B1 so + + + align:start position:0% +B1 so +we'll keep track of the total number of + + align:start position:0% +we'll keep track of the total number of + + + align:start position:0% +we'll keep track of the total number of +measures equals z the total we'll call + + align:start position:0% +measures equals z the total we'll call + + + align:start position:0% +measures equals z the total we'll call +them Walts like measures those where + + align:start position:0% +them Walts like measures those where + + + align:start position:0% +them Walts like measures those where +beat 3 is above beat one we'll call it + + align:start position:0% +beat 3 is above beat one we'll call it + + + align:start position:0% +beat 3 is above beat one we'll call it +zero for every measure in the score + + align:start position:0% +zero for every measure in the score + + + align:start position:0% +zero for every measure in the score +recurse get Elements by class + + align:start position:0% +recurse get Elements by class + + + align:start position:0% +recurse get Elements by class +measure um there's a reason why we'll + + align:start position:0% +measure um there's a reason why we'll + + + align:start position:0% +measure um there's a reason why we'll +use get Elements by class measure + + align:start position:0% +use get Elements by class measure + + + align:start position:0% +use get Elements by class measure +instead of measure 0 1 2 3 so mostly to + + align:start position:0% +instead of measure 0 1 2 3 so mostly to + + + align:start position:0% +instead of measure 0 1 2 3 so mostly to +do with the fact that sometimes there's + + align:start position:0% +do with the fact that sometimes there's + + + align:start position:0% +do with the fact that sometimes there's +two measure 3es or they're missing + + align:start position:0% +two measure 3es or they're missing + + + align:start position:0% +two measure 3es or they're missing +Measure 11 or something like that with + + align:start position:0% +Measure 11 or something like that with + + + align:start position:0% +Measure 11 or something like that with +there's measure 5 a and 5B if there's a + + align:start position:0% +there's measure 5 a and 5B if there's a + + + align:start position:0% +there's measure 5 a and 5B if there's a +first ending or something like that + + align:start position:0% +first ending or something like that + + + align:start position:0% +first ending or something like that +anyhow so we're going for every measure + + align:start position:0% +anyhow so we're going for every measure + + + align:start position:0% +anyhow so we're going for every measure +we increment the total number of + + align:start position:0% +we increment the total number of + + + align:start position:0% +we increment the total number of +measures by one and now um we look at + + align:start position:0% +measures by one and now um we look at + + + align:start position:0% +measures by one and now um we look at +one + + align:start position:0% + + + + align:start position:0% + +measure and we say if that's true then + + align:start position:0% +measure and we say if that's true then + + + align:start position:0% +measure and we say if that's true then +the total Walts + + align:start position:0% +the total Walts + + + align:start position:0% +the total Walts +like measures plus equal one and we're + + align:start position:0% +like measures plus equal one and we're + + + align:start position:0% +like measures plus equal one and we're +going to return the + + align:start position:0% +going to return the + + + align:start position:0% +going to return the +total WTS like measures divided by the + + align:start position:0% +total WTS like measures divided by the + + + align:start position:0% +total WTS like measures divided by the +total measures + + align:start position:0% +total measures + + + align:start position:0% +total measures +uh we're coding pretty fast so we'll + + align:start position:0% +uh we're coding pretty fast so we'll + + + align:start position:0% +uh we're coding pretty fast so we'll +just put as a to-do later um what if + + align:start position:0% +just put as a to-do later um what if + + + align:start position:0% +just put as a to-do later um what if +there are no total measures always make + + align:start position:0% +there are no total measures always make + + + align:start position:0% +there are no total measures always make +sure that we don't do a division by zero + + align:start position:0% +sure that we don't do a division by zero + + + align:start position:0% +sure that we don't do a division by zero +measure uh error but that can be a later + + align:start position:0% +measure uh error but that can be a later + + + align:start position:0% +measure uh error but that can be a later +thing so let's check this um + + align:start position:0% +thing so let's check this um + + + align:start position:0% +thing so let's check this um +proportion of beat 3 + + align:start position:0% +proportion of beat 3 + + + align:start position:0% +proportion of beat 3 +above beat one in the blue danu + + align:start position:0% + + + + align:start position:0% + +26% not really true seems a little bit + + align:start position:0% + + + + align:start position:0% + +low one two + + align:start position:0% +low one two + + + align:start position:0% +low one two +down well we'll check that later turns + + align:start position:0% +down well we'll check that later turns + + + align:start position:0% +down well we'll check that later turns +out it's not not that bad and BWB U + + align:start position:0% +out it's not not that bad and BWB U + + + align:start position:0% +out it's not not that bad and BWB U +sorry Buck CL this time it's actually + + align:start position:0% +sorry Buck CL this time it's actually + + + align:start position:0% +sorry Buck CL this time it's actually +even a little bit more interesting okay + + align:start position:0% +even a little bit more interesting okay + + + align:start position:0% +even a little bit more interesting okay +so in any case this is a feature we've + + align:start position:0% +so in any case this is a feature we've + + + align:start position:0% +so in any case this is a feature we've +just defined this particular feature + + align:start position:0% +just defined this particular feature + + + align:start position:0% +just defined this particular feature +figures out how often beat 3 is above + + align:start position:0% +figures out how often beat 3 is above + + + align:start position:0% +figures out how often beat 3 is above +beat one great what we can do now is + + align:start position:0% +beat one great what we can do now is + + + align:start position:0% +beat one great what we can do now is +these are individual features let's + + align:start position:0% +these are individual features let's + + + align:start position:0% +these are individual features let's +create something that does chains a + + align:start position:0% +create something that does chains a + + + align:start position:0% +create something that does chains a +whole bunch of features together well + + align:start position:0% +whole bunch of features together well + + + align:start position:0% +whole bunch of features together well +not this one whole bunch of features + + align:start position:0% +not this one whole bunch of features + + + align:start position:0% +not this one whole bunch of features +we'll + + align:start position:0% +we'll + + + align:start position:0% +we'll +get four features so we'll + + align:start position:0% +get four features so we'll + + + align:start position:0% +get four features so we'll +say our feature + + align:start position:0% +say our feature + + + align:start position:0% +say our feature +extractor will take in a + + align:start position:0% +extractor will take in a + + + align:start position:0% +extractor will take in a +score and it's going to return a tupple + + align:start position:0% +score and it's going to return a tupple + + + align:start position:0% +score and it's going to return a tupple +of a string an INT an INT a float and a + + align:start position:0% +of a string an INT an INT a float and a + + + align:start position:0% +of a string an INT an INT a float and a +b end okay what the heck what are these + + align:start position:0% +b end okay what the heck what are these + + + align:start position:0% +b end okay what the heck what are these +things going to be so first what we're + + align:start position:0% +things going to be so first what we're + + + align:start position:0% +things going to be so first what we're +going to do is we're going to take in + + align:start position:0% +going to do is we're going to take in + + + align:start position:0% +going to do is we're going to take in +score and we're going to + + align:start position:0% +score and we're going to + + + align:start position:0% +score and we're going to +um well we're going to say the file + + align:start position:0% +um well we're going to say the file + + + align:start position:0% +um well we're going to say the file +name of the score is going to be that + + align:start position:0% +name of the score is going to be that + + + align:start position:0% +name of the score is going to be that +first string um and you can get the file + + align:start position:0% +first string um and you can get the file + + + align:start position:0% +first string um and you can get the file +name from any music 21 core by getting + + align:start position:0% +name from any music 21 core by getting + + + align:start position:0% +name from any music 21 core by getting +his file path which is a path lip and + + align:start position:0% +his file path which is a path lip and + + + align:start position:0% +his file path which is a path lip and +getting the name which gets rid of all + + align:start position:0% +getting the name which gets rid of all + + + align:start position:0% +getting the name which gets rid of all +the directories and stuff great so we'll + + align:start position:0% +the directories and stuff great so we'll + + + align:start position:0% +the directories and stuff great so we'll +get the file name of something and we'll + + align:start position:0% +get the file name of something and we'll + + + align:start position:0% +get the file name of something and we'll +get the next thing we're going to get + + align:start position:0% +get the next thing we're going to get + + + align:start position:0% +get the next thing we're going to get +these two ins which are going to be the + + align:start position:0% +these two ins which are going to be the + + + align:start position:0% +these two ins which are going to be the +meter so we'll say the meter + + align:start position:0% +meter so we'll say the meter + + + align:start position:0% +meter so we'll say the meter +feature is where I get that from + + align:start position:0% +feature is where I get that from + + + align:start position:0% +feature is where I get that from +extract extract meter on that + + align:start position:0% +extract extract meter on that + + + align:start position:0% +extract extract meter on that +score next we're going to get this float + + align:start position:0% +score next we're going to get this float + + + align:start position:0% +score next we're going to get this float +which is going to be the beat 3 + + align:start position:0% +which is going to be the beat 3 + + + align:start position:0% +which is going to be the beat 3 +feature so we'll get the beat3 + + align:start position:0% +feature so we'll get the beat3 + + + align:start position:0% +feature so we'll get the beat3 +feature is the proportion propor sh why + + align:start position:0% +feature is the proportion propor sh why + + + align:start position:0% +feature is the proportion propor sh why +do I keep doing this beat three above + + align:start position:0% +do I keep doing this beat three above + + + align:start position:0% +do I keep doing this beat three above +beat one for that score great super oops + + align:start position:0% +beat one for that score great super oops + + + align:start position:0% +beat one for that score great super oops +I hit shift enter then we want to get + + align:start position:0% +I hit shift enter then we want to get + + + align:start position:0% +I hit shift enter then we want to get +the Boolean what we're going to do is if + + align:start position:0% +the Boolean what we're going to do is if + + + align:start position:0% +the Boolean what we're going to do is if +we're training a data set we're going to + + align:start position:0% +we're training a data set we're going to + + + align:start position:0% +we're training a data set we're going to +know whether or not something is a waltz + + align:start position:0% +know whether or not something is a waltz + + + align:start position:0% +know whether or not something is a waltz +so we'll say that Boolean is going to be + + align:start position:0% +so we'll say that Boolean is going to be + + + align:start position:0% +so we'll say that Boolean is going to be +true or false on whether something is a + + align:start position:0% +true or false on whether something is a + + + align:start position:0% +true or false on whether something is a +waltz and so we could say is + + align:start position:0% +waltz and so we could say is + + + align:start position:0% +waltz and so we could say is +Waltz + + align:start position:0% +Waltz + + + align:start position:0% +Waltz +equals if true if Waltz is in the file + + align:start position:0% +equals if true if Waltz is in the file + + + align:start position:0% +equals if true if Waltz is in the file +name or if lowercase vaults is in the + + align:start position:0% +name or if lowercase vaults is in the + + + align:start position:0% +name or if lowercase vaults is in the +file + + align:start position:0% +file + + + align:start position:0% +file +name file name so then we know the file + + align:start position:0% +name file name so then we know the file + + + align:start position:0% +name file name so then we know the file +name numerator and + + align:start position:0% +name numerator and + + + align:start position:0% +name numerator and +denominator a float of the proportion + + align:start position:0% +denominator a float of the proportion + + + align:start position:0% +denominator a float of the proportion +beat3 and whether or not science Walts + + align:start position:0% +beat3 and whether or not science Walts + + + align:start position:0% +beat3 and whether or not science Walts +this last particular um thing we'll some + + align:start position:0% +this last particular um thing we'll some + + + align:start position:0% +this last particular um thing we'll some +call this instead of is Walter sign + + align:start position:0% +call this instead of is Walter sign + + + align:start position:0% +call this instead of is Walter sign +we'll use generic term ground truth + + align:start position:0% +we'll use generic term ground truth + + + align:start position:0% +we'll use generic term ground truth +we'll also see it called the class so + + align:start position:0% +we'll also see it called the class so + + + align:start position:0% +we'll also see it called the class so +whether it's belongs to the waltz class + + align:start position:0% +whether it's belongs to the waltz class + + + align:start position:0% +whether it's belongs to the waltz class +or not so we can call it Walt or non- + + align:start position:0% +or not so we can call it Walt or non- + + + align:start position:0% +or not so we can call it Walt or non- +waltz or true false something like that + + align:start position:0% +waltz or true false something like that + + + align:start position:0% +waltz or true false something like that +now we want to return all these things + + align:start position:0% +now we want to return all these things + + + align:start position:0% +now we want to return all these things +as a tupple so tuples are created + + align:start position:0% +as a tupple so tuples are created + + + align:start position:0% +as a tupple so tuples are created +with a comma or with a parenthesis so + + align:start position:0% +with a comma or with a parenthesis so + + + align:start position:0% +with a comma or with a parenthesis so +we'll use the parenthesis the file name + + align:start position:0% +we'll use the parenthesis the file name + + + align:start position:0% +we'll use the parenthesis the file name +the meter features first argument which + + align:start position:0% +the meter features first argument which + + + align:start position:0% +the meter features first argument which +is the numerator meter + + align:start position:0% +is the numerator meter + + + align:start position:0% +is the numerator meter +features second argument which is the + + align:start position:0% +features second argument which is the + + + align:start position:0% +features second argument which is the +denominator the beat3 + + align:start position:0% +denominator the beat3 + + + align:start position:0% +denominator the beat3 +feature and the ground + + align:start position:0% +feature and the ground + + + align:start position:0% +feature and the ground +truth so let's see we'll run this + + align:start position:0% +truth so let's see we'll run this + + + align:start position:0% +truth so let's see we'll run this +feature ex let's call extractor let's + + align:start position:0% +feature ex let's call extractor let's + + + align:start position:0% +feature ex let's call extractor let's +call + + align:start position:0% +call + + + align:start position:0% +call +snap it properly F feature extractor on + + align:start position:0% +snap it properly F feature extractor on + + + align:start position:0% +snap it properly F feature extractor on +the blue denu + + align:start position:0% +the blue denu + + + align:start position:0% +the blue denu +and uh I still didn't spell it right why + + align:start position:0% +and uh I still didn't spell it right why + + + align:start position:0% +and uh I still didn't spell it right why +do I copy and paste there we + + align:start position:0% +do I copy and paste there we + + + align:start position:0% +do I copy and paste there we +go oh we can see blue Denny Waltz was in + + align:start position:0% +go oh we can see blue Denny Waltz was in + + + align:start position:0% +go oh we can see blue Denny Waltz was in +three + + align:start position:0% +three + + + align:start position:0% +three +four 26% has this beat proportion and + + align:start position:0% +four 26% has this beat proportion and + + + align:start position:0% +four 26% has this beat proportion and +true it is a Walt let's run our feature + + align:start position:0% +true it is a Walt let's run our feature + + + align:start position:0% +true it is a Walt let's run our feature +extract + + align:start position:0% +extract + + + align:start position:0% +extract +Tour on BW on + + align:start position:0% +Tour on BW on + + + align:start position:0% +Tour on BW on +B we'll see file name 44 35 false + + align:start position:0% +B we'll see file name 44 35 false + + + align:start position:0% +B we'll see file name 44 35 false +great So eventually we would want to + + align:start position:0% +great So eventually we would want to + + + align:start position:0% +great So eventually we would want to +have a computer system that can + + align:start position:0% +have a computer system that can + + + align:start position:0% +have a computer system that can +distinguish between one up between a + + align:start position:0% +distinguish between one up between a + + + align:start position:0% +distinguish between one up between a +waltz and not by learning all this + + align:start position:0% +waltz and not by learning all this + + + align:start position:0% +waltz and not by learning all this +information + + align:start position:0% +information + + + align:start position:0% +information +unfortunately I don't have enough waltes + + align:start position:0% +unfortunately I don't have enough waltes + + + align:start position:0% +unfortunately I don't have enough waltes +in my data set to do this so we're going + + align:start position:0% +in my data set to do this so we're going + + + align:start position:0% +in my data set to do this so we're going +to move to the next best thing we're + + align:start position:0% +to move to the next best thing we're + + + align:start position:0% +to move to the next best thing we're +going to get a jig so let's go ahead and + + align:start position:0% +going to get a jig so let's go ahead and + + + align:start position:0% +going to get a jig so let's go ahead and +um and grab a particular jig we have all + + align:start position:0% +um and grab a particular jig we have all + + + align:start position:0% +um and grab a particular jig we have all +of these jigs in this um in this data + + align:start position:0% +of these jigs in this um in this data + + + align:start position:0% +of these jigs in this um in this data +set which is really useful for people to + + align:start position:0% +set which is really useful for people to + + + align:start position:0% +set which is really useful for people to +know it's called + + align:start position:0% +know it's called + + + align:start position:0% +know it's called +Ryan's uh + + align:start position:0% +Ryan's uh + + + align:start position:0% +Ryan's uh +Mammoth + + align:start position:0% +Mammoth + + + align:start position:0% +Mammoth +collection it's for 19th century thing + + align:start position:0% +collection it's for 19th century thing + + + align:start position:0% +collection it's for 19th century thing +you can look it up it's very famous hi I + + align:start position:0% +you can look it up it's very famous hi I + + + align:start position:0% +you can look it up it's very famous hi I +wanted to jump in for a second and say + + align:start position:0% +wanted to jump in for a second and say + + + align:start position:0% +wanted to jump in for a second and say +something about this collection I'm + + align:start position:0% +something about this collection I'm + + + align:start position:0% +something about this collection I'm +planning on not using it again soon + + align:start position:0% +planning on not using it again soon + + + align:start position:0% +planning on not using it again soon +since I made this video I've realized + + align:start position:0% +since I made this video I've realized + + + align:start position:0% +since I made this video I've realized +that within Ryan's Mammoth collection + + align:start position:0% +that within Ryan's Mammoth collection + + + align:start position:0% +that within Ryan's Mammoth collection +there is a lot of what are called + + align:start position:0% +there is a lot of what are called + + + align:start position:0% +there is a lot of what are called +minstral songs that is songs that were + + align:start position:0% +minstral songs that is songs that were + + + align:start position:0% +minstral songs that is songs that were +performed um in the style of negro + + align:start position:0% +performed um in the style of negro + + + align:start position:0% +performed um in the style of negro +Melodies but by uh by white performers + + align:start position:0% +Melodies but by uh by white performers + + + align:start position:0% +Melodies but by uh by white performers +often in blackace and with texts which + + align:start position:0% +often in blackace and with texts which + + + align:start position:0% +often in blackace and with texts which +are not included in this collection + + align:start position:0% +are not included in this collection + + + align:start position:0% +are not included in this collection +thank goodness but with texts that uh + + align:start position:0% +thank goodness but with texts that uh + + + align:start position:0% +thank goodness but with texts that uh +denigrated uh Black Americans and black + + align:start position:0% +denigrated uh Black Americans and black + + + align:start position:0% +denigrated uh Black Americans and black +experience so I'm going to try to uh + + align:start position:0% +experience so I'm going to try to uh + + + align:start position:0% +experience so I'm going to try to uh +change this example as soon as I can and + + align:start position:0% +change this example as soon as I can and + + + align:start position:0% +change this example as soon as I can and +my apologies + + align:start position:0% +my apologies + + + align:start position:0% +my apologies +for what I didn't know then and what I + + align:start position:0% +for what I didn't know then and what I + + + align:start position:0% +for what I didn't know then and what I +know now and what I plan to continue to + + align:start position:0% +know now and what I plan to continue to + + + align:start position:0% +know now and what I plan to continue to +do to make computational musicology a + + align:start position:0% +do to make computational musicology a + + + align:start position:0% +do to make computational musicology a +more welcoming + + align:start position:0% +more welcoming + + + align:start position:0% +more welcoming +place we're going to be looking at the + + align:start position:0% +place we're going to be looking at the + + + align:start position:0% +place we're going to be looking at the +blooming Meadows Chi so um let's just + + align:start position:0% +blooming Meadows Chi so um let's just + + + align:start position:0% +blooming Meadows Chi so um let's just +we'll load that um + + align:start position:0% +we'll load that um + + + align:start position:0% +we'll load that um +blooming Corpus + + align:start position:0% +blooming Corpus + + + align:start position:0% +blooming Corpus +pars blo Meadow jig don't need the ABC + + align:start position:0% +pars blo Meadow jig don't need the ABC + + + align:start position:0% +pars blo Meadow jig don't need the ABC +you can leave it in however you want + + align:start position:0% +you can leave it in however you want + + + align:start position:0% +you can leave it in however you want +let's look at + + align:start position:0% +let's look at + + + align:start position:0% +let's look at +this in case you haven't seen a jig in a + + align:start position:0% +this in case you haven't seen a jig in a + + + align:start position:0% +this in case you haven't seen a jig in a +while it's kind of helpful for + + align:start position:0% +while it's kind of helpful for + + + align:start position:0% +while it's kind of helpful for +understanding so + + align:start position:0% +understanding so + + + align:start position:0% +understanding so +jig we speaking of 68 we got these + + align:start position:0% +jig we speaking of 68 we got these + + + align:start position:0% +jig we speaking of 68 we got these +violin bow marks we could use that as a + + align:start position:0% +violin bow marks we could use that as a + + + align:start position:0% +violin bow marks we could use that as a +feature extractor if it has violin + + align:start position:0% +feature extractor if it has violin + + + align:start position:0% +feature extractor if it has violin +markings it's more likely to be a jig if + + align:start position:0% +markings it's more likely to be a jig if + + + align:start position:0% +markings it's more likely to be a jig if +it doesn't it's less likely lots of Bo + + align:start position:0% +it doesn't it's less likely lots of Bo + + + align:start position:0% +it doesn't it's less likely lots of Bo +pieces of violin bow marks the boach + + align:start position:0% +pieces of violin bow marks the boach + + + align:start position:0% +pieces of violin bow marks the boach +violin part just they're not all jigs + + align:start position:0% +violin part just they're not all jigs + + + align:start position:0% +violin part just they're not all jigs +but you know so it's not going to be + + align:start position:0% +but you know so it's not going to be + + + align:start position:0% +but you know so it's not going to be +perfect but all these things kind of + + align:start position:0% +perfect but all these things kind of + + + align:start position:0% +perfect but all these things kind of +help but maybe that meter extractor 68 + + align:start position:0% +help but maybe that meter extractor 68 + + + align:start position:0% +help but maybe that meter extractor 68 +is going to be a little bit + + align:start position:0% +is going to be a little bit + + + align:start position:0% +is going to be a little bit +helpful so I happen to know that this + + align:start position:0% +helpful so I happen to know that this + + + align:start position:0% +helpful so I happen to know that this +little piece is a jig it's kind of nice + + align:start position:0% +little piece is a jig it's kind of nice + + + align:start position:0% +little piece is a jig it's kind of nice +short piece but there's a whole bunch of + + align:start position:0% +short piece but there's a whole bunch of + + + align:start position:0% +short piece but there's a whole bunch of +things so we're going to get from Ryan + + align:start position:0% +things so we're going to get from Ryan + + + align:start position:0% +things so we're going to get from Ryan +MTH collection and we'll use a different + + align:start position:0% +MTH collection and we'll use a different + + + align:start position:0% +MTH collection and we'll use a different +thing uh that we've used before into + + align:start position:0% +thing uh that we've used before into + + + align:start position:0% +thing uh that we've used before into +Corpus pars we're going to search + + align:start position:0% +Corpus pars we're going to search + + + align:start position:0% +Corpus pars we're going to search +everything for Ryan um I think + + align:start position:0% +everything for Ryan um I think + + + align:start position:0% +everything for Ryan um I think +everything in there is uh is part of + + align:start position:0% +everything in there is uh is part of + + + align:start position:0% +everything in there is uh is part of +this Ryan's mavi collection and we'll + + align:start position:0% +this Ryan's mavi collection and we'll + + + align:start position:0% +this Ryan's mavi collection and we'll +see that within Ryan there's going to be + + align:start position:0% +see that within Ryan there's going to be + + + align:start position:0% +see that within Ryan there's going to be +quite a number of pieces + + align:start position:0% +quite a number of pieces + + + align:start position:0% +quite a number of pieces +1,63 you'll see the first time you use + + align:start position:0% +1,63 you'll see the first time you use + + + align:start position:0% +1,63 you'll see the first time you use +Corpus search you um it takes some time + + align:start position:0% +Corpus search you um it takes some time + + + align:start position:0% +Corpus search you um it takes some time +but you can um you can use after the + + align:start position:0% +but you can um you can use after the + + + align:start position:0% +but you can um you can use after the +after you do it once it's often quite a + + align:start position:0% +after you do it once it's often quite a + + + align:start position:0% +after you do it once it's often quite a +bit faster super + + align:start position:0% +bit faster super + + + align:start position:0% +bit faster super +fast there we go okay so we're going to + + align:start position:0% +fast there we go okay so we're going to + + + align:start position:0% +fast there we go okay so we're going to +um have use that beat3 feature why not I + + align:start position:0% +um have use that beat3 feature why not I + + + align:start position:0% +um have use that beat3 feature why not I +mean we already have a feature and we're + + align:start position:0% +mean we already have a feature and we're + + + align:start position:0% +mean we already have a feature and we're +going to use the meter feature but let's + + align:start position:0% +going to use the meter feature but let's + + + align:start position:0% +going to use the meter feature but let's +use one more thing I've heard that jigs + + align:start position:0% +use one more thing I've heard that jigs + + + align:start position:0% +use one more thing I've heard that jigs +tend to come in a + + align:start position:0% +tend to come in a + + + align:start position:0% +tend to come in a +few in a few Keys a few key signatures + + align:start position:0% +few in a few Keys a few key signatures + + + align:start position:0% +few in a few Keys a few key signatures +um maybe one flat one sharp you know + + align:start position:0% +um maybe one flat one sharp you know + + + align:start position:0% +um maybe one flat one sharp you know +they don't tend to come in five flats + + align:start position:0% +they don't tend to come in five flats + + + align:start position:0% +they don't tend to come in five flats +that's kind of a hard thing for violin + + align:start position:0% +that's kind of a hard thing for violin + + + align:start position:0% +that's kind of a hard thing for violin +so let's go ahead and create um a sharp + + align:start position:0% +so let's go ahead and create um a sharp + + + align:start position:0% +so let's go ahead and create um a sharp +extractor so we'll call it uh we just + + align:start position:0% +extractor so we'll call it uh we just + + + align:start position:0% +extractor so we'll call it uh we just +called get + + align:start position:0% +called get + + + align:start position:0% +called get +Sharps because we'll just remind + + align:start position:0% +Sharps because we'll just remind + + + align:start position:0% +Sharps because we'll just remind +ourselves that feature extractor is + + align:start position:0% +ourselves that feature extractor is + + + align:start position:0% +ourselves that feature extractor is +nothing more than something that takes + + align:start position:0% +nothing more than something that takes + + + align:start position:0% +nothing more than something that takes +in a score some other piece of data and + + align:start position:0% +in a score some other piece of data and + + + align:start position:0% +in a score some other piece of data and +returns numbers in this case an integer + + align:start position:0% +returns numbers in this case an integer + + + align:start position:0% +returns numbers in this case an integer +uh we'll just TR put a try thing we'll + + align:start position:0% +uh we'll just TR put a try thing we'll + + + align:start position:0% +uh we'll just TR put a try thing we'll +return the score we're going to go + + align:start position:0% +return the score we're going to go + + + align:start position:0% +return the score we're going to go +through + + align:start position:0% +through + + + align:start position:0% +through +it + + align:start position:0% +it + + + align:start position:0% +it +recurse get all the elements okay use + + align:start position:0% +recurse get all the elements okay use + + + align:start position:0% +recurse get all the elements okay use +plural This Time by class key + + align:start position:0% +plural This Time by class key + + + align:start position:0% +plural This Time by class key +signature get the first one and return + + align:start position:0% +signature get the first one and return + + + align:start position:0% +signature get the first one and return +the number of Sharps remember if it's + + align:start position:0% +the number of Sharps remember if it's + + + align:start position:0% +the number of Sharps remember if it's +two Flats Sharps will be -2 and in case + + align:start position:0% +two Flats Sharps will be -2 and in case + + + align:start position:0% +two Flats Sharps will be -2 and in case +we can't find it uh might be an index + + align:start position:0% +we can't find it uh might be an index + + + align:start position:0% +we can't find it uh might be an index +error because uh there's zero um you can + + align:start position:0% +error because uh there's zero um you can + + + align:start position:0% +error because uh there's zero um you can +always in your own code that you don't + + align:start position:0% +always in your own code that you don't + + + align:start position:0% +always in your own code that you don't +turn in um and you don't put sign there + + align:start position:0% +turn in um and you don't put sign there + + + align:start position:0% +turn in um and you don't put sign there +you can just say except all + + align:start position:0% +you can just say except all + + + align:start position:0% +you can just say except all +errors return zero let's double check + + align:start position:0% +errors return zero let's double check + + + align:start position:0% +errors return zero let's double check +this um do we call it yeah + + align:start position:0% +this um do we call it yeah + + + align:start position:0% +this um do we call it yeah +blooming + + align:start position:0% +blooming + + + align:start position:0% +blooming +Sharps + + align:start position:0% +Sharps + + + align:start position:0% +Sharps +blooming get one let's remind ourselves + + align:start position:0% +blooming get one let's remind ourselves + + + align:start position:0% +blooming get one let's remind ourselves +blue denu should also be one + + align:start position:0% + + + + align:start position:0% + +great and that Bo piece should be + + align:start position:0% + + + + align:start position:0% + +three super okay so that seems to work a + + align:start position:0% +three super okay so that seems to work a + + + align:start position:0% +three super okay so that seems to work a +little bit now let's write our feature + + align:start position:0% + + + + align:start position:0% + +extractor or our multifeature extractor + + align:start position:0% +extractor or our multifeature extractor + + + align:start position:0% +extractor or our multifeature extractor +never really sure if our if feature + + align:start position:0% +never really sure if our if feature + + + align:start position:0% +never really sure if our if feature +extractor just refers to sign that gets + + align:start position:0% +extractor just refers to sign that gets + + + align:start position:0% +extractor just refers to sign that gets +one feature like get sharps or sign that + + align:start position:0% +one feature like get sharps or sign that + + + align:start position:0% +one feature like get sharps or sign that +gets a whole bunch features people + + align:start position:0% +gets a whole bunch features people + + + align:start position:0% +gets a whole bunch features people +aren't really clear on that so we're + + align:start position:0% +aren't really clear on that so we're + + + align:start position:0% +aren't really clear on that so we're +going to return again the string it's + + align:start position:0% +going to return again the string it's + + + align:start position:0% +going to return again the string it's +going to be the file name uh two + + align:start position:0% +going to be the file name uh two + + + align:start position:0% +going to be the file name uh two +integers for the metered mearian + + align:start position:0% +integers for the metered mearian + + + align:start position:0% +integers for the metered mearian +denominator pretty important float for + + align:start position:0% +denominator pretty important float for + + + align:start position:0% +denominator pretty important float for +that kind of silly uh beat3 thing but + + align:start position:0% +that kind of silly uh beat3 thing but + + + align:start position:0% +that kind of silly uh beat3 thing but +we'll add one more integer on + + align:start position:0% +we'll add one more integer on + + + align:start position:0% +we'll add one more integer on +um whether or not um yeah on the number + + align:start position:0% +um whether or not um yeah on the number + + + align:start position:0% +um whether or not um yeah on the number +of Sharps and instead returning a + + align:start position:0% +of Sharps and instead returning a + + + align:start position:0% +of Sharps and instead returning a +Boolean at the end we're going to switch + + align:start position:0% +Boolean at the end we're going to switch + + + align:start position:0% +Boolean at the end we're going to switch +this last little thing to returning an + + align:start position:0% +this last little thing to returning an + + + align:start position:0% +this last little thing to returning an +integer for whether or not something is + + align:start position:0% +integer for whether or not something is + + + align:start position:0% +integer for whether or not something is +a jig the ground truth and it's because + + align:start position:0% +a jig the ground truth and it's because + + + align:start position:0% +a jig the ground truth and it's because +most of the machine learning toolkits + + align:start position:0% +most of the machine learning toolkits + + + align:start position:0% +most of the machine learning toolkits +really + + align:start position:0% +really + + + align:start position:0% +really +um like working with numbers so might as + + align:start position:0% +um like working with numbers so might as + + + align:start position:0% +um like working with numbers so might as +well make our ground truth a number uh + + align:start position:0% +well make our ground truth a number uh + + + align:start position:0% +well make our ground truth a number uh +make a file name the file path name + + align:start position:0% +make a file name the file path name + + + align:start position:0% +make a file name the file path name +again as before you don't really need + + align:start position:0% +again as before you don't really need + + + align:start position:0% +again as before you don't really need +that there but it's going to be really + + align:start position:0% +that there but it's going to be really + + + align:start position:0% +that there but it's going to be really +helpful for figuring out why something's + + align:start position:0% +helpful for figuring out why something's + + + align:start position:0% +helpful for figuring out why something's +working or what particular pieces are + + align:start position:0% +working or what particular pieces are + + + align:start position:0% +working or what particular pieces are +wrong or right IOP I still had propor + + align:start position:0% +wrong or right IOP I still had propor + + + align:start position:0% +wrong or right IOP I still had propor +shot in my uh we in my clip board but + + align:start position:0% +shot in my uh we in my clip board but + + + align:start position:0% +shot in my uh we in my clip board but +okay so proportion B3 above B1 I always + + align:start position:0% +okay so proportion B3 above B1 I always + + + align:start position:0% +okay so proportion B3 above B1 I always +hit shift enter too early Sharps feature + + align:start position:0% +hit shift enter too early Sharps feature + + + align:start position:0% +hit shift enter too early Sharps feature +is better be get Sharps from score add + + align:start position:0% +is better be get Sharps from score add + + + align:start position:0% +is better be get Sharps from score add +our ground truth this case we said it's + + align:start position:0% +our ground truth this case we said it's + + + align:start position:0% +our ground truth this case we said it's +going to be an integer so we'll say int + + align:start position:0% +going to be an integer so we'll say int + + + align:start position:0% +going to be an integer so we'll say int +jig in file name or jig in file name two + + align:start position:0% +jig in file name or jig in file name two + + + align:start position:0% +jig in file name or jig in file name two +things to know one python int on true on + + align:start position:0% +things to know one python int on true on + + + align:start position:0% +things to know one python int on true on +int on true returns one int on false + + align:start position:0% +int on true returns one int on false + + + align:start position:0% +int on true returns one int on false +returns zero in fact uh in earlier + + align:start position:0% +returns zero in fact uh in earlier + + + align:start position:0% +returns zero in fact uh in earlier +versions of python true and false were + + align:start position:0% +versions of python true and false were + + + align:start position:0% +versions of python true and false were +just kind of aliases for one and zero + + align:start position:0% +just kind of aliases for one and zero + + + align:start position:0% +just kind of aliases for one and zero +thankfully that's a little bit better uh + + align:start position:0% +thankfully that's a little bit better uh + + + align:start position:0% +thankfully that's a little bit better uh +the other thing is again this what we've + + align:start position:0% +the other thing is again this what we've + + + align:start position:0% +the other thing is again this what we've +learned about garbage in garbage out I + + align:start position:0% +learned about garbage in garbage out I + + + align:start position:0% +learned about garbage in garbage out I +don't actually know if every single + + align:start position:0% +don't actually know if every single + + + align:start position:0% +don't actually know if every single +thing in uh this collection that has a + + align:start position:0% +thing in uh this collection that has a + + + align:start position:0% +thing in uh this collection that has a +word jig in its title is a jig and I + + align:start position:0% +word jig in its title is a jig and I + + + align:start position:0% +word jig in its title is a jig and I +definitely don't know that there's every + + align:start position:0% +definitely don't know that there's every + + + align:start position:0% +definitely don't know that there's every +piece in this collection that isn't a + + align:start position:0% +piece in this collection that isn't a + + + align:start position:0% +piece in this collection that isn't a +jig or that is a jig has jig in the + + align:start position:0% +jig or that is a jig has jig in the + + + align:start position:0% +jig or that is a jig has jig in the +title or that yeah that there might be + + align:start position:0% +title or that yeah that there might be + + + align:start position:0% +title or that yeah that there might be +jigs that don't have jig in the the + + align:start position:0% +jigs that don't have jig in the the + + + align:start position:0% +jigs that don't have jig in the the +title just as most rag rags in rag time + + align:start position:0% +title just as most rag rags in rag time + + + align:start position:0% +title just as most rag rags in rag time +in Scott Joplin have rag in their title + + align:start position:0% +in Scott Joplin have rag in their title + + + align:start position:0% +in Scott Joplin have rag in their title +Maple Leaf Rag so on but some of them + + align:start position:0% +Maple Leaf Rag so on but some of them + + + align:start position:0% +Maple Leaf Rag so on but some of them +don't the Entertainer is a rag it + + align:start position:0% +don't the Entertainer is a rag it + + + align:start position:0% +don't the Entertainer is a rag it +doesn't have rag in his title so so our + + align:start position:0% +doesn't have rag in his title so so our + + + align:start position:0% +doesn't have rag in his title so so our +ground truth isn't exactly the world's + + align:start position:0% +ground truth isn't exactly the world's + + + align:start position:0% +ground truth isn't exactly the world's +gospel truth this is something that that + + align:start position:0% +gospel truth this is something that that + + + align:start position:0% +gospel truth this is something that that +people neglect all the time in machine + + align:start position:0% +people neglect all the time in machine + + + align:start position:0% +people neglect all the time in machine +learning they keep training the computer + + align:start position:0% +learning they keep training the computer + + + align:start position:0% +learning they keep training the computer +to replicate + + align:start position:0% +to replicate + + + align:start position:0% +to replicate +truths that aren't necessarily true and + + align:start position:0% +truths that aren't necessarily true and + + + align:start position:0% +truths that aren't necessarily true and +you'll see this all over the place I was + + align:start position:0% +you'll see this all over the place I was + + + align:start position:0% +you'll see this all over the place I was +just working with uh Master student on a + + align:start position:0% +just working with uh Master student on a + + + align:start position:0% +just working with uh Master student on a +project where we're trying to train + + align:start position:0% +project where we're trying to train + + + align:start position:0% +project where we're trying to train +Optical music recognition to produce the + + align:start position:0% +Optical music recognition to produce the + + + align:start position:0% +Optical music recognition to produce the +exact ground truth that we had found + + align:start position:0% +exact ground truth that we had found + + + align:start position:0% +exact ground truth that we had found +encoded the thing is the ground truth + + align:start position:0% +encoded the thing is the ground truth + + + align:start position:0% +encoded the thing is the ground truth +had lots of Errors too so that's theci + + align:start position:0% +had lots of Errors too so that's theci + + + align:start position:0% +had lots of Errors too so that's theci +to know anyhow getting back to what are + + align:start position:0% +to know anyhow getting back to what are + + + align:start position:0% +to know anyhow getting back to what are +we going to return take a second see if + + align:start position:0% +we going to return take a second see if + + + align:start position:0% +we going to return take a second see if +you can figure this out based on what + + align:start position:0% +you can figure this out based on what + + + align:start position:0% +you can figure this out based on what +we've said return value is and what + + align:start position:0% +we've said return value is and what + + + align:start position:0% +we've said return value is and what +we've defined here great so we're going + + align:start position:0% +we've defined here great so we're going + + + align:start position:0% +we've defined here great so we're going +to return the file name meter + + align:start position:0% +to return the file name meter + + + align:start position:0% +to return the file name meter +feature zero meter feature one P3 + + align:start position:0% +feature zero meter feature one P3 + + + align:start position:0% +feature zero meter feature one P3 +feature Sharps feature and the ground + + align:start position:0% +feature Sharps feature and the ground + + + align:start position:0% +feature Sharps feature and the ground +truth + + align:start position:0% +truth + + + align:start position:0% +truth +great okay so now we just need to + + align:start position:0% +great okay so now we just need to + + + align:start position:0% +great okay so now we just need to +iterate over everything I want to show + + align:start position:0% +iterate over everything I want to show + + + align:start position:0% +iterate over everything I want to show +something when you iterate over a corpus + + align:start position:0% +something when you iterate over a corpus + + + align:start position:0% +something when you iterate over a corpus +search object object there's this thing + + align:start position:0% +search object object there's this thing + + + align:start position:0% +search object object there's this thing +called a metadata bundle that is to say + + align:start position:0% +called a metadata bundle that is to say + + + align:start position:0% +called a metadata bundle that is to say +you haven't actually parsed 1,63 pieces + + align:start position:0% +you haven't actually parsed 1,63 pieces + + + align:start position:0% +you haven't actually parsed 1,63 pieces +it just knows about the existence of + + align:start position:0% +it just knows about the existence of + + + align:start position:0% +it just knows about the existence of +1,63 pieces so when we say for um bundle + + align:start position:0% +1,63 pieces so when we say for um bundle + + + align:start position:0% +1,63 pieces so when we say for um bundle +in + + align:start position:0% +in + + + align:start position:0% +in +Ryan we can print the + + align:start position:0% +Ryan we can print the + + + align:start position:0% +Ryan we can print the +bundle and we can see that we have all + + align:start position:0% +bundle and we can see that we have all + + + align:start position:0% +bundle and we can see that we have all +of these um different Ines for + + align:start position:0% +of these um different Ines for + + + align:start position:0% +of these um different Ines for +pieces so what we'll do go ahead and do + + align:start position:0% +pieces so what we'll do go ahead and do + + + align:start position:0% +pieces so what we'll do go ahead and do +is instead of um getting but not actual + + align:start position:0% +is instead of um getting but not actual + + + align:start position:0% +is instead of um getting but not actual +pieces so to get the pieces we can say + + align:start position:0% +pieces so to get the pieces we can say + + + align:start position:0% +pieces so to get the pieces we can say +um piece pars equals bundle actually we + + align:start position:0% +um piece pars equals bundle actually we + + + align:start position:0% +um piece pars equals bundle actually we +call it to bundle say metadata + + align:start position:0% +call it to bundle say metadata + + + align:start position:0% +call it to bundle say metadata +entry since out in there metadata entry + + align:start position:0% +entry since out in there metadata entry + + + align:start position:0% +entry since out in there metadata entry +in Ryan + + align:start position:0% +in Ryan + + + align:start position:0% +in Ryan +entry piece pars is the metadata entry. + + align:start position:0% +entry piece pars is the metadata entry. + + + align:start position:0% +entry piece pars is the metadata entry. +parse that's going to take some + + align:start position:0% +parse that's going to take some + + + align:start position:0% +parse that's going to take some +time then we're going to print out the + + align:start position:0% +time then we're going to print out the + + + align:start position:0% +time then we're going to print out the +feature extraction + + align:start position:0% +feature extraction + + + align:start position:0% +feature extraction +on the piece + + align:start position:0% +on the piece + + + align:start position:0% +on the piece +pars you're going to learn to use this + + align:start position:0% +pars you're going to learn to use this + + + align:start position:0% +pars you're going to learn to use this +little button in a second because the + + align:start position:0% +little button in a second because the + + + align:start position:0% +little button in a second because the +stop button because it's going to take + + align:start position:0% +stop button because it's going to take + + + align:start position:0% +stop button because it's going to take +some time if you hit run but you're + + align:start position:0% +some time if you hit run but you're + + + align:start position:0% +some time if you hit run but you're +going to have to do it in a little bit + + align:start position:0% +going to have to do it in a little bit + + + align:start position:0% +going to have to do it in a little bit +oops feature extractor used to call it + + align:start position:0% +oops feature extractor used to call it + + + align:start position:0% +oops feature extractor used to call it +feature extraction but that + + align:start position:0% +feature extraction but that + + + align:start position:0% +feature extraction but that +and extract meter exact meter extract + + align:start position:0% +and extract meter exact meter extract + + + align:start position:0% +and extract meter exact meter extract +meter here we go so we're going to put + + align:start position:0% +meter here we go so we're going to put + + + align:start position:0% +meter here we go so we're going to put +this back here and uh let's go ahead and + + align:start position:0% +this back here and uh let's go ahead and + + + align:start position:0% +this back here and uh let's go ahead and +run this + + align:start position:0% +run this + + + align:start position:0% +run this +oops oh my goodness I cannot spell + + align:start position:0% +oops oh my goodness I cannot spell + + + align:start position:0% +oops oh my goodness I cannot spell +anything today okay here we go let's go + + align:start position:0% +anything today okay here we go let's go + + + align:start position:0% +anything today okay here we go let's go +ahead and runting this it shows that + + align:start position:0% +ahead and runting this it shows that + + + align:start position:0% +ahead and runting this it shows that +adil's hornpipe is I don't know this + + align:start position:0% +adil's hornpipe is I don't know this + + + align:start position:0% +adil's hornpipe is I don't know this +piece but it's in + + align:start position:0% +piece but it's in + + + align:start position:0% +piece but it's in +22 really seldom does beat three um is + + align:start position:0% +22 really seldom does beat three um is + + + align:start position:0% +22 really seldom does beat three um is +uh was offset two higher than offset one + + align:start position:0% +uh was offset two higher than offset one + + + align:start position:0% +uh was offset two higher than offset one +wow that is really really low and um + + align:start position:0% +wow that is really really low and um + + + align:start position:0% +wow that is really really low and um +it's in one sharp oh good Flats do work + + align:start position:0% +it's in one sharp oh good Flats do work + + + align:start position:0% +it's in one sharp oh good Flats do work +and it is zero it is not a jig it is a + + align:start position:0% +and it is zero it is not a jig it is a + + + align:start position:0% +and it is zero it is not a jig it is a +hornpipe I know we all know these + + align:start position:0% +hornpipe I know we all know these + + + align:start position:0% +hornpipe I know we all know these +differences between reels and hornpipes + + align:start position:0% +differences between reels and hornpipes + + + align:start position:0% +differences between reels and hornpipes +and Jigs and all these things um well + + align:start position:0% +and Jigs and all these things um well + + + align:start position:0% +and Jigs and all these things um well +maybe some of us got our Pirates like + + align:start position:0% +maybe some of us got our Pirates like + + + align:start position:0% +maybe some of us got our Pirates like +okay we can see here Bano o barley meal + + align:start position:0% +okay we can see here Bano o barley meal + + + align:start position:0% +okay we can see here Bano o barley meal +jig uh which is in + + align:start position:0% +jig uh which is in + + + align:start position:0% +jig uh which is in +68 has this feature it's in two sharps + + align:start position:0% +68 has this feature it's in two sharps + + + align:start position:0% +68 has this feature it's in two sharps +and there's a one here so is a jig so + + align:start position:0% +and there's a one here so is a jig so + + + align:start position:0% +and there's a one here so is a jig so +that works pretty well and we can scroll + + align:start position:0% +that works pretty well and we can scroll + + + align:start position:0% +that works pretty well and we can scroll +all the way through wow there's a lot of + + align:start position:0% +all the way through wow there's a lot of + + + align:start position:0% +all the way through wow there's a lot of +pieces okay great and some of them are + + align:start position:0% +pieces okay great and some of them are + + + align:start position:0% +pieces okay great and some of them are +jigs some of them are + + align:start position:0% + + + + align:start position:0% + +not okay so now we've extracted all this + + align:start position:0% +not okay so now we've extracted all this + + + align:start position:0% +not okay so now we've extracted all this +data if we put all of this into some + + align:start position:0% +data if we put all of this into some + + + align:start position:0% +data if we put all of this into some +sort of file somewhere um we will have + + align:start position:0% +sort of file somewhere um we will have + + + align:start position:0% +sort of file somewhere um we will have +it all done so I'm going to take a two + + align:start position:0% +it all done so I'm going to take a two + + + align:start position:0% +it all done so I'm going to take a two +second break and show how we move from + + align:start position:0% +second break and show how we move from + + + align:start position:0% +second break and show how we move from +feature abstraction to machine + + align:start position:0% +feature abstraction to machine + + + align:start position:0% +feature abstraction to machine +learning okay one of the most important + + align:start position:0% +learning okay one of the most important + + + align:start position:0% +learning okay one of the most important +things we're going to be thinking about + + align:start position:0% +things we're going to be thinking about + + + align:start position:0% +things we're going to be thinking about +when we think about machine learning is + + align:start position:0% +when we think about machine learning is + + + align:start position:0% +when we think about machine learning is +that we're going to be training the + + align:start position:0% +that we're going to be training the + + + align:start position:0% +that we're going to be training the +computer on a certain set of data + + align:start position:0% +computer on a certain set of data + + + align:start position:0% +computer on a certain set of data +training our algorithms training our + + align:start position:0% +training our algorithms training our + + + align:start position:0% +training our algorithms training our +neural networks or whatever artificial + + align:start position:0% +neural networks or whatever artificial + + + align:start position:0% +neural networks or whatever artificial +intelligence and machine learning + + align:start position:0% +intelligence and machine learning + + + align:start position:0% +intelligence and machine learning +algorithm we choose to use on some + + align:start position:0% +algorithm we choose to use on some + + + align:start position:0% +algorithm we choose to use on some +portion of the data and then we want to + + align:start position:0% +portion of the data and then we want to + + + align:start position:0% +portion of the data and then we want to +see how good is the computer doing so + + align:start position:0% +see how good is the computer doing so + + + align:start position:0% +see how good is the computer doing so +we're going to hold out some portion of + + align:start position:0% +we're going to hold out some portion of + + + align:start position:0% +we're going to hold out some portion of +the data to be our test to see well if + + align:start position:0% +the data to be our test to see well if + + + align:start position:0% +the data to be our test to see well if +the training data is somewhat like the + + align:start position:0% +the training data is somewhat like the + + + align:start position:0% +the training data is somewhat like the +test data but the computer seen the + + align:start position:0% +test data but the computer seen the + + + align:start position:0% +test data but the computer seen the +training data and it hasn't seen the + + align:start position:0% +training data and it hasn't seen the + + + align:start position:0% +training data and it hasn't seen the +test data how well does it learn from + + align:start position:0% +test data how well does it learn from + + + align:start position:0% +test data how well does it learn from +the training data in order to make um + + align:start position:0% +the training data in order to make um + + + align:start position:0% +the training data in order to make um +identifications in the test data and + + align:start position:0% +identifications in the test data and + + + align:start position:0% +identifications in the test data and +there are lots of different ways of + + align:start position:0% +there are lots of different ways of + + + align:start position:0% +there are lots of different ways of +doing this please take a machine + + align:start position:0% +doing this please take a machine + + + align:start position:0% +doing this please take a machine +learning class take an artificial + + align:start position:0% +learning class take an artificial + + + align:start position:0% +learning class take an artificial +intelligence class so you can learn + + align:start position:0% +intelligence class so you can learn + + + align:start position:0% +intelligence class so you can learn +about one hold out out cross validation + + align:start position:0% +about one hold out out cross validation + + + align:start position:0% +about one hold out out cross validation +or on10th uh hold out lots of different + + align:start position:0% +or on10th uh hold out lots of different + + + align:start position:0% +or on10th uh hold out lots of different +ways that we can do this better than + + align:start position:0% +ways that we can do this better than + + + align:start position:0% +ways that we can do this better than +what we're going to do but instead for + + align:start position:0% +what we're going to do but instead for + + + align:start position:0% +what we're going to do but instead for +now to make things very simple for those + + align:start position:0% +now to make things very simple for those + + + align:start position:0% +now to make things very simple for those +who for whom this is going to be your + + align:start position:0% +who for whom this is going to be your + + + align:start position:0% +who for whom this is going to be your +first introduction to artificial + + align:start position:0% +first introduction to artificial + + + align:start position:0% +first introduction to artificial +intelligence and machine learning what + + align:start position:0% +intelligence and machine learning what + + + align:start position:0% +intelligence and machine learning what +we're going to do is we're going to + + align:start position:0% +we're going to do is we're going to + + + align:start position:0% +we're going to do is we're going to +divide all of our training data into two + + align:start position:0% +divide all of our training data into two + + + align:start position:0% +divide all of our training data into two +parts all of our data into half of it as + + align:start position:0% +parts all of our data into half of it as + + + align:start position:0% +parts all of our data into half of it as +the test data and half of it as the + + align:start position:0% +the test data and half of it as the + + + align:start position:0% +the test data and half of it as the +training data and I'm just going to go + + align:start position:0% +training data and I'm just going to go + + + align:start position:0% +training data and I'm just going to go +through and almost always do everything + + align:start position:0% +through and almost always do everything + + + align:start position:0% +through and almost always do everything +in up this one to test this one training + + align:start position:0% +in up this one to test this one training + + + align:start position:0% +in up this one to test this one training +this one test this one training it's + + align:start position:0% +this one test this one training it's + + + align:start position:0% +this one test this one training it's +just going to make things easier but + + align:start position:0% +just going to make things easier but + + + align:start position:0% +just going to make things easier but +there are better ways to do + + align:start position:0% +there are better ways to do + + + align:start position:0% +there are better ways to do +it not for now let's get to some + + align:start position:0% +it not for now let's get to some + + + align:start position:0% +it not for now let's get to some +artificial intelligence and machine + + align:start position:0% +artificial intelligence and machine + + + align:start position:0% +artificial intelligence and machine +learning okay let's go ahead and and + + align:start position:0% +learning okay let's go ahead and and + + + align:start position:0% +learning okay let's go ahead and and +open up two files for writing I'm going + + align:start position:0% +open up two files for writing I'm going + + + align:start position:0% +open up two files for writing I'm going +to call + + align:start position:0% +to call + + + align:start position:0% +to call +them uh they're on my desktop o now you + + align:start position:0% +them uh they're on my desktop o now you + + + align:start position:0% +them uh they're on my desktop o now you +know my secret secret path um we'll call + + align:start position:0% +know my secret secret path um we'll call + + + align:start position:0% +know my secret secret path um we'll call +it train data. tab we're going to open + + align:start position:0% +it train data. tab we're going to open + + + align:start position:0% +it train data. tab we're going to open +this for writing and we'll call it as + + align:start position:0% +this for writing and we'll call it as + + + align:start position:0% +this for writing and we'll call it as +training if you're not familiar with + + align:start position:0% +training if you're not familiar with + + + align:start position:0% +training if you're not familiar with +python um file handles please take a + + align:start position:0% +python um file handles please take a + + + align:start position:0% +python um file handles please take a +second to look this up because otherwise + + align:start position:0% +second to look this up because otherwise + + + align:start position:0% +second to look this up because otherwise +this won't make much sense but + + align:start position:0% +this won't make much sense but + + + align:start position:0% +this won't make much sense but +essentially we're going to have um two + + align:start position:0% +essentially we're going to have um two + + + align:start position:0% +essentially we're going to have um two +files so we're going to be able to write + + align:start position:0% +files so we're going to be able to write + + + align:start position:0% +files so we're going to be able to write +two going back and forth one versus the + + align:start position:0% +two going back and forth one versus the + + + align:start position:0% +two going back and forth one versus the +other there's going to be better ways of + + align:start position:0% +other there's going to be better ways of + + + align:start position:0% +other there's going to be better ways of +doing this but this how we're going to + + align:start position:0% +doing this but this how we're going to + + + align:start position:0% +doing this but this how we're going to +do it first okay we're going to need to + + align:start position:0% +do it first okay we're going to need to + + + align:start position:0% +do it first okay we're going to need to +say uh for a lot of various algorithms + + align:start position:0% +say uh for a lot of various algorithms + + + align:start position:0% +say uh for a lot of various algorithms +we're going to need to be able to say + + align:start position:0% +we're going to need to be able to say + + + align:start position:0% +we're going to need to be able to say +what our column names are so we'll say + + align:start position:0% +what our column names are so we'll say + + + align:start position:0% +what our column names are so we'll say +our columns are going to be a series of + + align:start position:0% +our columns are going to be a series of + + + align:start position:0% +our columns are going to be a series of +tab separated values so that's what + + align:start position:0% +tab separated values so that's what + + + align:start position:0% +tab separated values so that's what +these tab files are going to be series + + align:start position:0% +these tab files are going to be series + + + align:start position:0% +these tab files are going to be series +of tab separated values that join these + + align:start position:0% +of tab separated values that join these + + + align:start position:0% +of tab separated values that join these +um titles file + + align:start position:0% +um titles file + + + align:start position:0% +um titles file +name numerator doesn't matter what these + + align:start position:0% +name numerator doesn't matter what these + + + align:start position:0% +name numerator doesn't matter what these +are called + + align:start position:0% +are called + + + align:start position:0% +are called +denominator beat3 proportion I'm not + + align:start position:0% +denominator beat3 proportion I'm not + + + align:start position:0% +denominator beat3 proportion I'm not +going to make myself type that again and + + align:start position:0% +going to make myself type that again and + + + align:start position:0% +going to make myself type that again and +we'll say is jig at the end for a ground + + align:start position:0% +we'll say is jig at the end for a ground + + + align:start position:0% +we'll say is jig at the end for a ground +truth fantastic okay those are columns + + align:start position:0% +truth fantastic okay those are columns + + + align:start position:0% +truth fantastic okay those are columns +and first I'm going to do is write to + + align:start position:0% +and first I'm going to do is write to + + + align:start position:0% +and first I'm going to do is write to +each of our + + align:start position:0% +each of our + + + align:start position:0% +each of our +different + + align:start position:0% +different + + + align:start position:0% +different +files write our columns with a line + + align:start position:0% +files write our columns with a line + + + align:start position:0% +files write our columns with a line +break at the + + align:start position:0% +break at the + + + align:start position:0% +break at the +end go testing is going to write columns + + align:start position:0% +end go testing is going to write columns + + + align:start position:0% +end go testing is going to write columns +with a line break at the end great now + + align:start position:0% +with a line break at the end great now + + + align:start position:0% +with a line break at the end great now +we want to describe what kind of value + + align:start position:0% +we want to describe what kind of value + + + align:start position:0% +we want to describe what kind of value +what kind of value um will a machine + + align:start position:0% +what kind of value um will a machine + + + align:start position:0% +what kind of value um will a machine +learning toolkit expect to get from file + + align:start position:0% +learning toolkit expect to get from file + + + align:start position:0% +learning toolkit expect to get from file +name uh stram numerator integer beat3 + + align:start position:0% +name uh stram numerator integer beat3 + + + align:start position:0% +name uh stram numerator integer beat3 +float things like that so we'll say our + + align:start position:0% +float things like that so we'll say our + + + align:start position:0% +float things like that so we'll say our +descriptions are going to be and these + + align:start position:0% +descriptions are going to be and these + + + align:start position:0% +descriptions are going to be and these +are pretty standard formats but they're + + align:start position:0% +are pretty standard formats but they're + + + align:start position:0% +are pretty standard formats but they're +not python so look at this it's not Str + + align:start position:0% +not python so look at this it's not Str + + + align:start position:0% +not python so look at this it's not Str +it's string and we'll say that our + + align:start position:0% +it's string and we'll say that our + + + align:start position:0% +it's string and we'll say that our +integers are discrete data with a I not + + align:start position:0% +integers are discrete data with a I not + + + align:start position:0% +integers are discrete data with a I not +discrete like indiscrete + + align:start position:0% +discrete like indiscrete + + + align:start position:0% +discrete like indiscrete +but okay I won't make a joke but discret + + align:start position:0% +but okay I won't make a joke but discret + + + align:start position:0% +but okay I won't make a joke but discret +like integer values uh but beat3 data + + align:start position:0% +like integer values uh but beat3 data + + + align:start position:0% +like integer values uh but beat3 data +can be continuous it can be 1.2 1.21 so + + align:start position:0% +can be continuous it can be 1.2 1.21 so + + + align:start position:0% +can be continuous it can be 1.2 1.21 so +on and then another discrete data for + + align:start position:0% +on and then another discrete data for + + + align:start position:0% +on and then another discrete data for +the number Sharps and then for is J it's + + align:start position:0% +the number Sharps and then for is J it's + + + align:start position:0% +the number Sharps and then for is J it's +also it's 01 so it's going to be + + align:start position:0% +also it's 01 so it's going to be + + + align:start position:0% +also it's 01 so it's going to be +discrete data fantastic we're going to + + align:start position:0% +discrete data fantastic we're going to + + + align:start position:0% +discrete data fantastic we're going to +write + + align:start position:0% +write + + + align:start position:0% +write +these to these files the descriptions + + align:start position:0% +these to these files the descriptions + + + align:start position:0% +these to these files the descriptions +also boom okay + + align:start position:0% +also boom okay + + + align:start position:0% +also boom okay +great this um we also tend to put these + + align:start position:0% +great this um we also tend to put these + + + align:start position:0% +great this um we also tend to put these +meta variables in and they say um if + + align:start position:0% +meta variables in and they say um if + + + align:start position:0% +meta variables in and they say um if +anything is special if anything is + + align:start position:0% +anything is special if anything is + + + align:start position:0% +anything is special if anything is +unlike the rest well the ones that are + + align:start position:0% +unlike the rest well the ones that are + + + align:start position:0% +unlike the rest well the ones that are +special is the first thing string is + + align:start position:0% +special is the first thing string is + + + align:start position:0% +special is the first thing string is +just a meta data that is to say it just + + align:start position:0% +just a meta data that is to say it just + + + align:start position:0% +just a meta data that is to say it just +means um something so that we can more + + align:start position:0% +means um something so that we can more + + + align:start position:0% +means um something so that we can more +easily diagnose uh problems and look + + align:start position:0% +easily diagnose uh problems and look + + + align:start position:0% +easily diagnose uh problems and look +things up later we don't actually need + + align:start position:0% +things up later we don't actually need + + + align:start position:0% +things up later we don't actually need +it we're not going to study the file + + align:start position:0% +it we're not going to study the file + + + align:start position:0% +it we're not going to study the file +name um and then these are just normal + + align:start position:0% +name um and then these are just normal + + + align:start position:0% +name um and then these are just normal +things numerator denominator beat three + + align:start position:0% +things numerator denominator beat three + + + align:start position:0% +things numerator denominator beat three +number of Sharps and then at the very + + align:start position:0% +number of Sharps and then at the very + + + align:start position:0% +number of Sharps and then at the very +end the final thing is our class the + + align:start position:0% +end the final thing is our class the + + + align:start position:0% +end the final thing is our class the +thing that's we're trying to learn we're + + align:start position:0% +thing that's we're trying to learn we're + + + align:start position:0% +thing that's we're trying to learn we're +trying to learn does this + + align:start position:0% +trying to learn does this + + + align:start position:0% +trying to learn does this +information + + align:start position:0% +information + + + align:start position:0% +information +98.1 + + align:start position:0% +98.1 + + + align:start position:0% +98.1 +11112 describe a jig or not the class of + + align:start position:0% +11112 describe a jig or not the class of + + + align:start position:0% +11112 describe a jig or not the class of +objects that is a jig great so these are + + align:start position:0% +objects that is a jig great so these are + + + align:start position:0% +objects that is a jig great so these are +our meta variables and we're going to + + align:start position:0% +our meta variables and we're going to + + + align:start position:0% +our meta variables and we're going to +write them to again our see do I still + + align:start position:0% +write them to again our see do I still + + + align:start position:0% +write them to again our see do I still +have that + + align:start position:0% +have that + + + align:start position:0% +have that +no going to write that to our training + + align:start position:0% +no going to write that to our training + + + align:start position:0% +no going to write that to our training +and to our testing + + align:start position:0% +and to our testing + + + align:start position:0% +and to our testing +great um here I can kind of do this + + align:start position:0% +great um here I can kind of do this + + + align:start position:0% +great um here I can kind of do this +anyhow we can + + align:start position:0% +anyhow we can + + + align:start position:0% +anyhow we can +cat that file this is a um these magic + + align:start position:0% +cat that file this is a um these magic + + + align:start position:0% +cat that file this is a um these magic +things are stuff you can do in Jupiter + + align:start position:0% +things are stuff you can do in Jupiter + + + align:start position:0% +things are stuff you can do in Jupiter +that you can't in normal python um but + + align:start position:0% +that you can't in normal python um but + + + align:start position:0% +that you can't in normal python um but +it'll see train + + align:start position:0% +it'll see train + + + align:start position:0% +it'll see train +data tab yep we can kind of see what + + align:start position:0% +data tab yep we can kind of see what + + + align:start position:0% +data tab yep we can kind of see what +we've written out there okay great now + + align:start position:0% +we've written out there okay great now + + + align:start position:0% +we've written out there okay great now +we're going to take this and we're going + + align:start position:0% +we're going to take this and we're going + + + align:start position:0% +we're going to take this and we're going +to write more things it we're going to + + align:start position:0% +to write more things it we're going to + + + align:start position:0% +to write more things it we're going to +write to um these into these two files + + align:start position:0% +write to um these into these two files + + + align:start position:0% +write to um these into these two files +information about from our feature + + align:start position:0% +information about from our feature + + + align:start position:0% +information about from our feature +extractions so we're going to go back + + align:start position:0% +extractions so we're going to go back + + + align:start position:0% +extractions so we're going to go back +for each piece in ryion um + + align:start position:0% +for each piece in ryion um + + + align:start position:0% +for each piece in ryion um +enumerate Ryan um and enumerate says our + + align:start position:0% +enumerate Ryan um and enumerate says our + + + align:start position:0% +enumerate Ryan um and enumerate says our +first thing goes into piece and we'll + + align:start position:0% +first thing goes into piece and we'll + + + align:start position:0% +first thing goes into piece and we'll +call it I actually we'll not call it + + align:start position:0% +call it I actually we'll not call it + + + align:start position:0% +call it I actually we'll not call it +piece we'll call it uh metad data entry + + align:start position:0% +piece we'll call it uh metad data entry + + + align:start position:0% +piece we'll call it uh metad data entry +great + + align:start position:0% +great + + + align:start position:0% +great +uh we'll say piece pars is our + + align:start position:0% +uh we'll say piece pars is our + + + align:start position:0% +uh we'll say piece pars is our +metadata entry + + align:start position:0% +metadata entry + + + align:start position:0% +metadata entry +parse great and our + + align:start position:0% +parse great and our + + + align:start position:0% +parse great and our +features are our featured + + align:start position:0% +features are our featured + + + align:start position:0% +features are our featured +extractor on pie + + align:start position:0% + + + + align:start position:0% + +pars pie pars and now we're going to uh + + align:start position:0% +pars pie pars and now we're going to uh + + + align:start position:0% +pars pie pars and now we're going to uh +create make a string out of that feature + + align:start position:0% +create make a string out of that feature + + + align:start position:0% +create make a string out of that feature +string equals tab separated version of + + align:start position:0% +string equals tab separated version of + + + align:start position:0% +string equals tab separated version of +the string value of each element for the + + align:start position:0% +the string value of each element for the + + + align:start position:0% +the string value of each element for the +element in features okay yeah we should + + align:start position:0% +element in features okay yeah we should + + + align:start position:0% +element in features okay yeah we should +call it + + align:start position:0% +call it + + + align:start position:0% +call it +f + + align:start position:0% +f + + + align:start position:0% +f +fantastic and if I is + + align:start position:0% +fantastic and if I is + + + align:start position:0% +fantastic and if I is +even no if I is odd uh we'll write it to + + align:start position:0% +even no if I is odd uh we'll write it to + + + align:start position:0% +even no if I is odd uh we'll write it to +the training + + align:start position:0% + + + + align:start position:0% + +data with uh new + + align:start position:0% +data with uh new + + + align:start position:0% +data with uh new +line and + + align:start position:0% +line and + + + align:start position:0% +line and +otherwise we'll write it to the testing + + align:start position:0% + + + + align:start position:0% + +data with a new line great hopefully I + + align:start position:0% +data with a new line great hopefully I + + + align:start position:0% +data with a new line great hopefully I +didn't type anything wrong we'll find + + align:start position:0% +didn't type anything wrong we'll find + + + align:start position:0% +didn't type anything wrong we'll find +out in a + + align:start position:0% + + + + align:start position:0% + +second great it seems to be working it's + + align:start position:0% +second great it seems to be working it's + + + align:start position:0% +second great it seems to be working it's +slow one of the things I'm going to + + align:start position:0% +slow one of the things I'm going to + + + align:start position:0% +slow one of the things I'm going to +eventually learn is that everything's + + align:start position:0% +eventually learn is that everything's + + + align:start position:0% +eventually learn is that everything's +slower when I'm screen recording so uh + + align:start position:0% +slower when I'm screen recording so uh + + + align:start position:0% +slower when I'm screen recording so uh +we could see that yep there's a bunch of + + align:start position:0% +we could see that yep there's a bunch of + + + align:start position:0% +we could see that yep there's a bunch of +of things in here most important one can + + align:start position:0% +of things in here most important one can + + + align:start position:0% +of things in here most important one can +we get a jig good it has a one at the + + align:start position:0% +we get a jig good it has a one at the + + + align:start position:0% +we get a jig good it has a one at the +end if it's a jig zero at the end if + + align:start position:0% +end if it's a jig zero at the end if + + + align:start position:0% +end if it's a jig zero at the end if +it's something else oh these jigs are 68 + + align:start position:0% +it's something else oh these jigs are 68 + + + align:start position:0% +it's something else oh these jigs are 68 +oh look there's a jig it begins in 98 so + + align:start position:0% +oh look there's a jig it begins in 98 so + + + align:start position:0% +oh look there's a jig it begins in 98 so +maybe it's the eight that's more + + align:start position:0% +maybe it's the eight that's more + + + align:start position:0% +maybe it's the eight that's more +important I don't know we'll see if the + + align:start position:0% +important I don't know we'll see if the + + + align:start position:0% +important I don't know we'll see if the +computer can figure this out uh we don't + + align:start position:0% +computer can figure this out uh we don't + + + align:start position:0% +computer can figure this out uh we don't +need to look at all 1,000 entries + + align:start position:0% +need to look at all 1,000 entries + + + align:start position:0% +need to look at all 1,000 entries +Jupiter does a nice way of not putting + + align:start position:0% +Jupiter does a nice way of not putting + + + align:start position:0% +Jupiter does a nice way of not putting +that all together okay great so now we + + align:start position:0% +that all together okay great so now we + + + align:start position:0% +that all together okay great so now we +have something that we can feed into an + + align:start position:0% +have something that we can feed into an + + + align:start position:0% +have something that we can feed into an +artificial intelligence classification + + align:start position:0% +artificial intelligence classification + + + align:start position:0% +artificial intelligence classification +program so we don't have one so we're + + align:start position:0% +program so we don't have one so we're + + + align:start position:0% +program so we don't have one so we're +going to write one of our own so we're + + align:start position:0% +going to write one of our own so we're + + + align:start position:0% +going to write one of our own so we're +going to say neural network ah just + + align:start position:0% +going to say neural network ah just + + + align:start position:0% +going to say neural network ah just +kidding no that's not what this class is + + align:start position:0% +kidding no that's not what this class is + + + align:start position:0% +kidding no that's not what this class is +about that's other classes we're going + + align:start position:0% +about that's other classes we're going + + + align:start position:0% +about that's other classes we're going +to install one so go ahead and install + + align:start position:0% +to install one so go ahead and install + + + align:start position:0% +to install one so go ahead and install +Orange 3 which is a really great pass + + align:start position:0% +Orange 3 which is a really great pass + + + align:start position:0% +Orange 3 which is a really great pass +package oh hey I already have installed + + align:start position:0% +package oh hey I already have installed + + + align:start position:0% +package oh hey I already have installed +yours probably takes a little bit longer + + align:start position:0% +yours probably takes a little bit longer + + + align:start position:0% +yours probably takes a little bit longer +than that great + + align:start position:0% +than that great + + + align:start position:0% +than that great +super so now I have orange 3 um orange 3 + + align:start position:0% +super so now I have orange 3 um orange 3 + + + align:start position:0% +super so now I have orange 3 um orange 3 +names it stuff kind of funny um so I + + align:start position:0% +names it stuff kind of funny um so I + + + align:start position:0% +names it stuff kind of funny um so I +always because I've been using it for a + + align:start position:0% +always because I've been using it for a + + + align:start position:0% +always because I've been using it for a +long time I just imported it it's not + + align:start position:0% +long time I just imported it it's not + + + align:start position:0% +long time I just imported it it's not +Orange 3 let's call it orange great now + + align:start position:0% +Orange 3 let's call it orange great now + + + align:start position:0% +Orange 3 let's call it orange great now +what we're going to do is we're going to + + align:start position:0% +what we're going to do is we're going to + + + align:start position:0% +what we're going to do is we're going to +load in our training + + align:start position:0% +load in our training + + + align:start position:0% +load in our training +data from an orange data table based on + + align:start position:0% +data from an orange data table based on + + + align:start position:0% +data from an orange data table based on +that information + + align:start position:0% + + + + align:start position:0% + +so train data. + + align:start position:0% +so train data. + + + align:start position:0% +so train data. +tab uh I reverted myself to using camel + + align:start position:0% +tab uh I reverted myself to using camel + + + align:start position:0% +tab uh I reverted myself to using camel +case things I probably shouldn't but I'm + + align:start position:0% +case things I probably shouldn't but I'm + + + align:start position:0% +case things I probably shouldn't but I'm +not going to + + align:start position:0% +not going to + + + align:start position:0% +not going to +rewrite everything now though it doesn't + + align:start position:0% +rewrite everything now though it doesn't + + + align:start position:0% +rewrite everything now though it doesn't +look like much but I have a lot in my + + align:start position:0% +look like much but I have a lot in my + + + align:start position:0% +look like much but I have a lot in my +sleeve okay so we're going to load those + + align:start position:0% +sleeve okay so we're going to load those + + + align:start position:0% +sleeve okay so we're going to load those +two great um we can look at train data + + align:start position:0% +two great um we can look at train data + + + align:start position:0% +two great um we can look at train data +little bit yep whole bunch of stuff uh + + align:start position:0% +little bit yep whole bunch of stuff uh + + + align:start position:0% +little bit yep whole bunch of stuff uh +these are I think map plot live is type + + align:start position:0% +these are I think map plot live is type + + + align:start position:0% +these are I think map plot live is type +things okay great so what we want to do + + align:start position:0% +things okay great so what we want to do + + + align:start position:0% +things okay great so what we want to do +is um create a bunch of Learners things + + align:start position:0% +is um create a bunch of Learners things + + + align:start position:0% +is um create a bunch of Learners things +that can classify and understand data + + align:start position:0% +that can classify and understand data + + + align:start position:0% +that can classify and understand data +and try to make guesses about things our + + align:start position:0% +and try to make guesses about things our + + + align:start position:0% +and try to make guesses about things our +first learner is kind of like the + + align:start position:0% +first learner is kind of like the + + + align:start position:0% +first learner is kind of like the +placebo of Learners uh it's called the + + align:start position:0% +placebo of Learners uh it's called the + + + align:start position:0% +placebo of Learners uh it's called the +majority learner uh and there's other + + align:start position:0% +majority learner uh and there's other + + + align:start position:0% +majority learner uh and there's other +ways of doing this but we'll use this + + align:start position:0% +ways of doing this but we'll use this + + + align:start position:0% +ways of doing this but we'll use this +one + + align:start position:0% +one + + + align:start position:0% +one +and the majority learner is um is is + + align:start position:0% +and the majority learner is um is is + + + align:start position:0% +and the majority learner is um is is +pretty cool it just looks at the data it + + align:start position:0% +pretty cool it just looks at the data it + + + align:start position:0% +pretty cool it just looks at the data it +um it looks at what we put in the + + align:start position:0% +um it looks at what we put in the + + + align:start position:0% +um it looks at what we put in the +training data and it says you know what + + align:start position:0% +training data and it says you know what + + + align:start position:0% +training data and it says you know what +there's about three times as many things + + align:start position:0% +there's about three times as many things + + + align:start position:0% +there's about three times as many things +that are not jigs as there are jigs so I + + align:start position:0% +that are not jigs as there are jigs so I + + + align:start position:0% +that are not jigs as there are jigs so I +can get three out of four right if I + + align:start position:0% +can get three out of four right if I + + + align:start position:0% +can get three out of four right if I +just learn to always vote with majority + + align:start position:0% +just learn to always vote with majority + + + align:start position:0% +just learn to always vote with majority +I don't know anything about music but + + align:start position:0% +I don't know anything about music but + + + align:start position:0% +I don't know anything about music but +I'll just say I'll always say that's not + + align:start position:0% +I'll just say I'll always say that's not + + + align:start position:0% +I'll just say I'll always say that's not +a jig and you know what I'll usually be + + align:start position:0% +a jig and you know what I'll usually be + + + align:start position:0% +a jig and you know what I'll usually be +right um so never classify things + + align:start position:0% +right um so never classify things + + + align:start position:0% +right um so never classify things +according to hey uh is this right or + + align:start position:0% +according to hey uh is this right or + + + align:start position:0% +according to hey uh is this right or +wrong you know did did it get it right + + align:start position:0% +wrong you know did did it get it right + + + align:start position:0% +wrong you know did did it get it right +more than half the time no classify how + + align:start position:0% +more than half the time no classify how + + + align:start position:0% +more than half the time no classify how +you're doing against did it do did it do + + align:start position:0% +you're doing against did it do did it do + + + align:start position:0% +you're doing against did it do did it do +better than the majority learner + + align:start position:0% +better than the majority learner + + + align:start position:0% +better than the majority learner +correct um you're going to now if you + + align:start position:0% +correct um you're going to now if you + + + align:start position:0% +correct um you're going to now if you +don't know what this is we're going to + + align:start position:0% +don't know what this is we're going to + + + align:start position:0% +don't know what this is we're going to +learn what um in uh uh K nearest + + align:start position:0% +learn what um in uh uh K nearest + + + align:start position:0% +learn what um in uh uh K nearest +neighbors is KNN learner uh + + align:start position:0% +neighbors is KNN learner uh + + + align:start position:0% +neighbors is KNN learner uh +classification + + align:start position:0% +classification + + + align:start position:0% +classification +classification + + align:start position:0% +classification + + + align:start position:0% +classification +KNN learner and this is a pretty + + align:start position:0% +KNN learner and this is a pretty + + + align:start position:0% +KNN learner and this is a pretty +standard artificial intelligence + + align:start position:0% +standard artificial intelligence + + + align:start position:0% +standard artificial intelligence +learning algorithm um and so I'm not + + align:start position:0% +learning algorithm um and so I'm not + + + align:start position:0% +learning algorithm um and so I'm not +going to say too much about that so we + + align:start position:0% +going to say too much about that so we + + + align:start position:0% +going to say too much about that so we +have we create a kind of learner thing + + align:start position:0% +have we create a kind of learner thing + + + align:start position:0% +have we create a kind of learner thing +and our classifier is a learner that's + + align:start position:0% +and our classifier is a learner that's + + + align:start position:0% +and our classifier is a learner that's +been that's going to work on a + + align:start position:0% +been that's going to work on a + + + align:start position:0% +been that's going to work on a +particular set of data our training data + + align:start position:0% +particular set of data our training data + + + align:start position:0% +particular set of data our training data +okay good so we create a learner create + + align:start position:0% +okay good so we create a learner create + + + align:start position:0% +okay good so we create a learner create +a classifier hasn't actually learned + + align:start position:0% +a classifier hasn't actually learned + + + align:start position:0% +a classifier hasn't actually learned +anything yet but it's going to be ready + + align:start position:0% +anything yet but it's going to be ready + + + align:start position:0% +anything yet but it's going to be ready +for for doing that okay + + align:start position:0% +for for doing that okay + + + align:start position:0% +for for doing that okay +um now we're going to check how often + + align:start position:0% +um now we're going to check how often + + + align:start position:0% +um now we're going to check how often +does the majority learner get things uh + + align:start position:0% +does the majority learner get things uh + + + align:start position:0% +does the majority learner get things uh +how many times does it get it correct + + align:start position:0% +how many times does it get it correct + + + align:start position:0% +how many times does it get it correct +and how many times does um the kers + + align:start position:0% +and how many times does um the kers + + + align:start position:0% +and how many times does um the kers +neighbors learner get things + + align:start position:0% +neighbors learner get things + + + align:start position:0% +neighbors learner get things +correct and how many total things are + + align:start position:0% +correct and how many total things are + + + align:start position:0% +correct and how many total things are +there + + align:start position:0% +there + + + align:start position:0% +there +uh we get that as I need floats still + + align:start position:0% +uh we get that as I need floats still + + + align:start position:0% +uh we get that as I need floats still +thinking too much how to think like + + align:start position:0% +thinking too much how to think like + + + align:start position:0% +thinking too much how to think like +python + + align:start position:0% +python + + + align:start position:0% +python +Tu so how many test data there + + align:start position:0% +Tu so how many test data there + + + align:start position:0% +Tu so how many test data there +are go ah and see okay 532 in the test + + align:start position:0% + + + + align:start position:0% + +data the training data does not need to + + align:start position:0% +data the training data does not need to + + + align:start position:0% +data the training data does not need to +be exactly the same size or even close + + align:start position:0% +be exactly the same size or even close + + + align:start position:0% +be exactly the same size or even close +the same size as the test data + + align:start position:0% +the same size as the test data + + + align:start position:0% +the same size as the test data +but in this case they are great so now + + align:start position:0% +but in this case they are great so now + + + align:start position:0% +but in this case they are great so now +we're going to iterate through each of + + align:start position:0% +we're going to iterate through each of + + + align:start position:0% +we're going to iterate through each of +the rows + + align:start position:0% +the rows + + + align:start position:0% +the rows +um of um of our test data not our + + align:start position:0% +um of um of our test data not our + + + align:start position:0% +um of um of our test data not our +training + + align:start position:0% +training + + + align:start position:0% +training +data so we're going to know what row + + align:start position:0% +data so we're going to know what row + + + align:start position:0% +data so we're going to know what row +number we are on I and then test row and + + align:start position:0% +number we are on I and then test row and + + + align:start position:0% +number we are on I and then test row and +then the majority learner is going to + + align:start position:0% +then the majority learner is going to + + + align:start position:0% +then the majority learner is going to +make a guess based on the data in the + + align:start position:0% +make a guess based on the data in the + + + align:start position:0% +make a guess based on the data in the +test row wh the majority learner is + + align:start position:0% +test row wh the majority learner is + + + align:start position:0% +test row wh the majority learner is +really stupid so its guess is always + + align:start position:0% +really stupid so its guess is always + + + align:start position:0% +really stupid so its guess is always +going to be it's not a jig then Ker's + + align:start position:0% +going to be it's not a jig then Ker's + + + align:start position:0% +going to be it's not a jig then Ker's +neighbor is going to make a guess and + + align:start position:0% +neighbor is going to make a guess and + + + align:start position:0% +neighbor is going to make a guess and +we're hope that K's neighbor is making a + + align:start position:0% +we're hope that K's neighbor is making a + + + align:start position:0% +we're hope that K's neighbor is making a +guess based on some intelligence that it + + align:start position:0% +guess based on some intelligence that it + + + align:start position:0% +guess based on some intelligence that it +has or fake intelligence I mean it's + + align:start position:0% +has or fake intelligence I mean it's + + + align:start position:0% +has or fake intelligence I mean it's +called artificial intelligence for a + + align:start position:0% +called artificial intelligence for a + + + align:start position:0% +called artificial intelligence for a +reason and then we get to see in this + + align:start position:0% +reason and then we get to see in this + + + align:start position:0% +reason and then we get to see in this +case what the actual answer is with the + + align:start position:0% +case what the actual answer is with the + + + align:start position:0% +case what the actual answer is with the +class whether it's a jig or not so + + align:start position:0% +class whether it's a jig or not so + + + align:start position:0% +class whether it's a jig or not so +that's our real answer so we know this + + align:start position:0% +that's our real answer so we know this + + + align:start position:0% +that's our real answer so we know this +but K nearest neighbor is not allowed to + + align:start position:0% +but K nearest neighbor is not allowed to + + + align:start position:0% +but K nearest neighbor is not allowed to +look at this we really hope the + + align:start position:0% +look at this we really hope the + + + align:start position:0% +look at this we really hope the +computer's not peing uh otherwise all + + align:start position:0% +computer's not peing uh otherwise all + + + align:start position:0% +computer's not peing uh otherwise all +artificial intelligence is kind of + + align:start position:0% +artificial intelligence is kind of + + + align:start position:0% +artificial intelligence is kind of +screwed okay we'll just print out some + + align:start position:0% +screwed okay we'll just print out some + + + align:start position:0% +screwed okay we'll just print out some +test data that um the + + align:start position:0% +test data that um the + + + align:start position:0% +test data that um the +row I is + + align:start position:0% +row I is + + + align:start position:0% +row I is +uh a little bit of the information about + + align:start position:0% +uh a little bit of the information about + + + align:start position:0% +uh a little bit of the information about +our set that should be good gri will'll + + align:start position:0% +our set that should be good gri will'll + + + align:start position:0% +our set that should be good gri will'll +print out that the answer to row I + + align:start position:0% +print out that the answer to row I + + + align:start position:0% +print out that the answer to row I +is + + align:start position:0% + + + + align:start position:0% + +jig + + align:start position:0% +jig + + + align:start position:0% +jig +give whe + + align:start position:0% + + + + align:start position:0% + +answer I think that works else not + + align:start position:0% + + + + align:start position:0% + +check + + align:start position:0% + + + + align:start position:0% + +and and then we'll put in a tab we'll + + align:start position:0% +and and then we'll put in a tab we'll + + + align:start position:0% +and and then we'll put in a tab we'll +say k neighbor got it right or wrong + + align:start position:0% +say k neighbor got it right or wrong + + + align:start position:0% +say k neighbor got it right or wrong +correct right if k&n's if the K nearest + + align:start position:0% +correct right if k&n's if the K nearest + + + align:start position:0% +correct right if k&n's if the K nearest +neighbor's guess is the same as the real + + align:start position:0% +neighbor's guess is the same as the real + + + align:start position:0% +neighbor's guess is the same as the real +answer else + + align:start position:0% +answer else + + + align:start position:0% +answer else +wrong that's some pretty tough stuff + + align:start position:0% +wrong that's some pretty tough stuff + + + align:start position:0% +wrong that's some pretty tough stuff +Oran can't even get that right good + + align:start position:0% +Oran can't even get that right good + + + align:start position:0% +Oran can't even get that right good +okay um we'll print a blank line after + + align:start position:0% +okay um we'll print a blank line after + + + align:start position:0% +okay um we'll print a blank line after +that if the majority guesss if the + + align:start position:0% +that if the majority guesss if the + + + align:start position:0% +that if the majority guesss if the +majority guessed + + align:start position:0% +majority guessed + + + align:start position:0% +majority guessed +right then the majority correct + + align:start position:0% + + + + align:start position:0% + +INR if k n + + align:start position:0% +INR if k n + + + align:start position:0% +INR if k n +neighbors guess is + + align:start position:0% +neighbors guess is + + + align:start position:0% +neighbors guess is +right so we're just checking at this + + align:start position:0% +right so we're just checking at this + + + align:start position:0% +right so we're just checking at this +point how how good is this cares + + align:start position:0% +point how how good is this cares + + + align:start position:0% +point how how good is this cares +neighbors correct okay this going to be + + align:start position:0% +neighbors correct okay this going to be + + + align:start position:0% +neighbors correct okay this going to be +one + + align:start position:0% +one + + + align:start position:0% +one +bigger + + align:start position:0% +bigger + + + align:start position:0% +bigger +great so we'll go ahead and let that run + + align:start position:0% +great so we'll go ahead and let that run + + + align:start position:0% +great so we'll go ahead and let that run +oops uh claes are very nice oops they + + align:start position:0% +oops uh claes are very nice oops they + + + align:start position:0% +oops uh claes are very nice oops they +screw siging up + + align:start position:0% + + + + align:start position:0% + +um oops there we go uh I have to cast + + align:start position:0% +um oops there we go uh I have to cast + + + align:start position:0% +um oops there we go uh I have to cast +this as a list because where is it this + + align:start position:0% +this as a list because where is it this + + + align:start position:0% +this as a list because where is it this +data can't be sliced but lists can okay + + align:start position:0% +data can't be sliced but lists can okay + + + align:start position:0% +data can't be sliced but lists can okay +so that going on you know I probably + + align:start position:0% +so that going on you know I probably + + + align:start position:0% +so that going on you know I probably +need to reset my data so let's go ahead + + align:start position:0% +need to reset my data so let's go ahead + + + align:start position:0% +need to reset my data so let's go ahead +and do that it's going to be printing + + align:start position:0% +and do that it's going to be printing + + + align:start position:0% +and do that it's going to be printing +cool not jig K neighbors got it wrong + + align:start position:0% +cool not jig K neighbors got it wrong + + + align:start position:0% +cool not jig K neighbors got it wrong +not jig Kors got it right good good so + + align:start position:0% +not jig Kors got it right good good so + + + align:start position:0% +not jig Kors got it right good good so +hey see a lot of got it right I like + + align:start position:0% +hey see a lot of got it right I like + + + align:start position:0% +hey see a lot of got it right I like +that I like that okay here's the Moment + + align:start position:0% +that I like that okay here's the Moment + + + align:start position:0% +that I like that okay here's the Moment +of Truth um without machine + + align:start position:0% +of Truth um without machine + + + align:start position:0% +of Truth um without machine +learning there's a majority learner + + align:start position:0% +learning there's a majority learner + + + align:start position:0% +learning there's a majority learner +majority + + align:start position:0% +majority + + + align:start position:0% +majority +correct always put things into um into + + align:start position:0% +correct always put things into um into + + + align:start position:0% +correct always put things into um into +uh percentages always round your + + align:start position:0% +uh percentages always round your + + + align:start position:0% +uh percentages always round your +percentages toci reasonable nobody wants + + align:start position:0% +percentages toci reasonable nobody wants + + + align:start position:0% +percentages toci reasonable nobody wants +to see all those dangling digits okay so + + align:start position:0% +to see all those dangling digits okay so + + + align:start position:0% +to see all those dangling digits okay so +it got that number right and we'll say + + align:start position:0% +it got that number right and we'll say + + + align:start position:0% +it got that number right and we'll say +with K andn Machine learning we got the + + align:start position:0% +with K andn Machine learning we got the + + + align:start position:0% +with K andn Machine learning we got the +KNN correct how well do we + + align:start position:0% +KNN correct how well do we + + + align:start position:0% +KNN correct how well do we +do without machine learning got it 77% + + align:start position:0% +do without machine learning got it 77% + + + align:start position:0% +do without machine learning got it 77% +right K nearest neighbors got it 95% + + align:start position:0% +right K nearest neighbors got it 95% + + + align:start position:0% +right K nearest neighbors got it 95% +right wow okay that's pretty awesome + + align:start position:0% +right wow okay that's pretty awesome + + + align:start position:0% +right wow okay that's pretty awesome +that's a lot better than I thought when + + align:start position:0% +that's a lot better than I thought when + + + align:start position:0% +that's a lot better than I thought when +I um when I thought I would do this um + + align:start position:0% +I um when I thought I would do this um + + + align:start position:0% +I um when I thought I would do this um +by the way one of the things we can do + + align:start position:0% +by the way one of the things we can do + + + align:start position:0% +by the way one of the things we can do +you you probably want to keep track of + + align:start position:0% +you you probably want to keep track of + + + align:start position:0% +you you probably want to keep track of +your uh of your data and don't um don't + + align:start position:0% +your uh of your data and don't um don't + + + align:start position:0% +your uh of your data and don't um don't +do this but we'll just go ahead and + + align:start position:0% +do this but we'll just go ahead and + + + align:start position:0% +do this but we'll just go ahead and +check does it make a difference if we + + align:start position:0% +check does it make a difference if we + + + align:start position:0% +check does it make a difference if we +swap the training and the test + + align:start position:0% + + + + align:start position:0% + +data oops not training data training + + align:start position:0% + + + + align:start position:0% + +data do we get a fluke + + align:start position:0% +data do we get a fluke + + + align:start position:0% +data do we get a fluke +and we can go ahead and + + align:start position:0% +and we can go ahead and + + + align:start position:0% +and we can go ahead and +run 72 and 94 so yeah still pretty good + + align:start position:0% +run 72 and 94 so yeah still pretty good + + + align:start position:0% +run 72 and 94 so yeah still pretty good +doesn't matter which one we do I'm going + + align:start position:0% +doesn't matter which one we do I'm going + + + align:start position:0% +doesn't matter which one we do I'm going +to switch that back because I will + + align:start position:0% +to switch that back because I will + + + align:start position:0% +to switch that back because I will +totally uh make that mistake but yeah so + + align:start position:0% +totally uh make that mistake but yeah so + + + align:start position:0% +totally uh make that mistake but yeah so +we're doing really well with this so + + align:start position:0% +we're doing really well with this so + + + align:start position:0% +we're doing really well with this so +this is how you can do artificial + + align:start position:0% +this is how you can do artificial + + + align:start position:0% +this is how you can do artificial +intelligence with machine + + align:start position:0% + + + + align:start position:0% + +learning but that's been a little bit + + align:start position:0% +learning but that's been a little bit + + + align:start position:0% +learning but that's been a little bit +hard so + + align:start position:0% +hard so + + + align:start position:0% +hard so +fortunately music 21 has some tools to + + align:start position:0% +fortunately music 21 has some tools to + + + align:start position:0% +fortunately music 21 has some tools to +make a lot of these things even easier + + align:start position:0% +make a lot of these things even easier + + + align:start position:0% +make a lot of these things even easier +here so music 21 feature extraction will + + align:start position:0% +here so music 21 feature extraction will + + + align:start position:0% +here so music 21 feature extraction will +be the last topic that we're going to + + align:start position:0% +be the last topic that we're going to + + + align:start position:0% +be the last topic that we're going to +talk about + + align:start position:0% +talk about + + + align:start position:0% +talk about +today so we can go ahead and import from + + align:start position:0% +today so we can go ahead and import from + + + align:start position:0% +today so we can go ahead and import from +music 21 the features + + align:start position:0% + + + + align:start position:0% + +module great so within the features + + align:start position:0% +module great so within the features + + + align:start position:0% +module great so within the features +module there are things called data sets + + align:start position:0% +module there are things called data sets + + + align:start position:0% +module there are things called data sets +so let's create um um training + + align:start position:0% +so let's create um um training + + + align:start position:0% +so let's create um um training +set which will be a data set um with a + + align:start position:0% +set which will be a data set um with a + + + align:start position:0% +set which will be a data set um with a +class label of is jig we call ground + + align:start position:0% +class label of is jig we call ground + + + align:start position:0% +class label of is jig we call ground +trth or whatever and we'll create an + + align:start position:0% +trth or whatever and we'll create an + + + align:start position:0% +trth or whatever and we'll create an +identical one U for our test + + align:start position:0% +identical one U for our test + + + align:start position:0% +identical one U for our test +set testing set great so these are just + + align:start position:0% +set testing set great so these are just + + + align:start position:0% +set testing set great so these are just +um things that are ready to + + align:start position:0% +um things that are ready to + + + align:start position:0% +um things that are ready to +add two important things a set of data + + align:start position:0% +add two important things a set of data + + + align:start position:0% +add two important things a set of data +that is Stream So a whole bunch of + + align:start position:0% +that is Stream So a whole bunch of + + + align:start position:0% +that is Stream So a whole bunch of +streams uh will be added to both the + + align:start position:0% +streams uh will be added to both the + + + align:start position:0% +streams uh will be added to both the +training and the test set and also a set + + align:start position:0% +training and the test set and also a set + + + align:start position:0% +training and the test set and also a set +of feature + + align:start position:0% +of feature + + + align:start position:0% +of feature +extractors I'm not going to explain + + align:start position:0% +extractors I'm not going to explain + + + align:start position:0% +extractors I'm not going to explain +today how to write new feature + + align:start position:0% +today how to write new feature + + + align:start position:0% +today how to write new feature +extractors in the way music 21 expects + + align:start position:0% +extractors in the way music 21 expects + + + align:start position:0% +extractors in the way music 21 expects +them but they're basically pretty + + align:start position:0% +them but they're basically pretty + + + align:start position:0% +them but they're basically pretty +similar to what we've just been writing + + align:start position:0% +similar to what we've just been writing + + + align:start position:0% +similar to what we've just been writing +with functions except they're kind of + + align:start position:0% +with functions except they're kind of + + + align:start position:0% +with functions except they're kind of +expected to be + + align:start position:0% +expected to be + + + align:start position:0% +expected to be +classes but we don't really have to + + align:start position:0% +classes but we don't really have to + + + align:start position:0% +classes but we don't really have to +because music 21 has a whole bunch of + + align:start position:0% +because music 21 has a whole bunch of + + + align:start position:0% +because music 21 has a whole bunch of +features + + align:start position:0% +features + + + align:start position:0% +features +extractors some of them come from this + + align:start position:0% +extractors some of them come from this + + + align:start position:0% +extractors some of them come from this +amazing toolkit called J symbolic or the + + align:start position:0% +amazing toolkit called J symbolic or the + + + align:start position:0% +amazing toolkit called J symbolic or the +reinterpretations of Corey McKay's J + + align:start position:0% +reinterpretations of Corey McKay's J + + + align:start position:0% +reinterpretations of Corey McKay's J +symbolic toolkit which is in Java and um + + align:start position:0% +symbolic toolkit which is in Java and um + + + align:start position:0% +symbolic toolkit which is in Java and um +they have numbers like D1 is the overall + + align:start position:0% +they have numbers like D1 is the overall + + + align:start position:0% +they have numbers like D1 is the overall +dynamic range features not all of them + + align:start position:0% +dynamic range features not all of them + + + align:start position:0% +dynamic range features not all of them +have been implemented um eyes are + + align:start position:0% +have been implemented um eyes are + + + align:start position:0% +have been implemented um eyes are +instrument features you can probably see + + align:start position:0% +instrument features you can probably see + + + align:start position:0% +instrument features you can probably see +that um the percentage of all notes + + align:start position:0% +that um the percentage of all notes + + + align:start position:0% +that um the percentage of all notes +being played by electric guitars + + align:start position:0% +being played by electric guitars + + + align:start position:0% +being played by electric guitars +if you know something about jigs is + + align:start position:0% +if you know something about jigs is + + + align:start position:0% +if you know something about jigs is +probably not going to be very helpful to + + align:start position:0% +probably not going to be very helpful to + + + align:start position:0% +probably not going to be very helpful to +um to classifying whether or not + + align:start position:0% +um to classifying whether or not + + + align:start position:0% +um to classifying whether or not +something is a jig but maybe the average + + align:start position:0% +something is a jig but maybe the average + + + align:start position:0% +something is a jig but maybe the average +melodic interval will tell you something + + align:start position:0% +melodic interval will tell you something + + + align:start position:0% +melodic interval will tell you something +like that or how often there are melodic + + align:start position:0% +like that or how often there are melodic + + + align:start position:0% +like that or how often there are melodic +thirds or melodic fifths or maybe you + + align:start position:0% +thirds or melodic fifths or maybe you + + + align:start position:0% +thirds or melodic fifths or maybe you +know other things might tell sign so + + align:start position:0% +know other things might tell sign so + + + align:start position:0% +know other things might tell sign so +these are Melody features pitch features + + align:start position:0% +these are Melody features pitch features + + + align:start position:0% +these are Melody features pitch features +and so on um there's Rhythm features + + align:start position:0% +and so on um there's Rhythm features + + + align:start position:0% +and so on um there's Rhythm features +that's going to be pretty important um + + align:start position:0% +that's going to be pretty important um + + + align:start position:0% +that's going to be pretty important um +uh where do we have r31 initial time + + align:start position:0% +uh where do we have r31 initial time + + + align:start position:0% +uh where do we have r31 initial time +signature feature R32 compound or simple + + align:start position:0% +signature feature R32 compound or simple + + + align:start position:0% +signature feature R32 compound or simple +meure features and so on so we could add + + align:start position:0% +meure features and so on so we could add + + + align:start position:0% +meure features and so on so we could add +a bunch of these features in and we + + align:start position:0% +a bunch of these features in and we + + + align:start position:0% +a bunch of these features in and we +remember the names and within the music + + align:start position:0% +remember the names and within the music + + + align:start position:0% +remember the names and within the music +21 documentation there will be um + + align:start position:0% +21 documentation there will be um + + + align:start position:0% +21 documentation there will be um +certain things that will tell you you + + align:start position:0% +certain things that will tell you you + + + align:start position:0% +certain things that will tell you you +know uh triple meter features set to one + + align:start position:0% +know uh triple meter features set to one + + + align:start position:0% +know uh triple meter features set to one +if the numerator of the initial time + + align:start position:0% +if the numerator of the initial time + + + align:start position:0% +if the numerator of the initial time +signature is three or zero otherwise and + + align:start position:0% +signature is three or zero otherwise and + + + align:start position:0% +signature is three or zero otherwise and +this shows you how how it can work um so + + align:start position:0% +this shows you how how it can work um so + + + align:start position:0% +this shows you how how it can work um so +we can give a particular piece and it + + align:start position:0% +we can give a particular piece and it + + + align:start position:0% +we can give a particular piece and it +will tell us that BWB 66.6 is zero not + + align:start position:0% +will tell us that BWB 66.6 is zero not + + + align:start position:0% +will tell us that BWB 66.6 is zero not +in triple meter okay um we've already + + align:start position:0% +in triple meter okay um we've already + + + align:start position:0% +in triple meter okay um we've already +done something really really great um + + align:start position:0% +done something really really great um + + + align:start position:0% +done something really really great um +and so I will tell you that if we use + + align:start position:0% +and so I will tell you that if we use + + + align:start position:0% +and so I will tell you that if we use +this very similar feature extractors the + + align:start position:0% +this very similar feature extractors the + + + align:start position:0% +this very similar feature extractors the +ones we did before we're going to get + + align:start position:0% +ones we did before we're going to get + + + align:start position:0% +ones we did before we're going to get +the same um the same results but one of + + align:start position:0% +the same um the same results but one of + + + align:start position:0% +the same um the same results but one of +the other things we can do is we can + + align:start position:0% +the other things we can do is we can + + + align:start position:0% +the other things we can do is we can +just use a whole bunch of pretty random + + align:start position:0% +just use a whole bunch of pretty random + + + align:start position:0% +just use a whole bunch of pretty random +ones so we'll get um these features by + + align:start position:0% +ones so we'll get um these features by + + + align:start position:0% +ones so we'll get um these features by +ID and these are a bunch of features + + align:start position:0% +ID and these are a bunch of features + + + align:start position:0% +ID and these are a bunch of features +that I used to classify um various + + align:start position:0% +that I used to classify um various + + + align:start position:0% +that I used to classify um various +pieces of I think it was 16th 15th + + align:start position:0% +pieces of I think it was 16th 15th + + + align:start position:0% +pieces of I think it was 16th 15th +century music no 16th century music so + + align:start position:0% +century music no 16th century music so + + + align:start position:0% +century music no 16th century music so +they're not exactly super tuned for what + + align:start position:0% +they're not exactly super tuned for what + + + align:start position:0% +they're not exactly super tuned for what +we're going to do um um a lot of them + + align:start position:0% +we're going to do um um a lot of them + + + align:start position:0% +we're going to do um um a lot of them +are melodic features and so on uh well + + align:start position:0% +are melodic features and so on uh well + + + align:start position:0% +are melodic features and so on uh well +you see scroll over see which ones + + align:start position:0% +you see scroll over see which ones + + + align:start position:0% +you see scroll over see which ones +haven't done pitch features pitch + + align:start position:0% +haven't done pitch features pitch + + + align:start position:0% +haven't done pitch features pitch +feature + + align:start position:0% +feature + + + align:start position:0% +feature + + align:start position:0% + + + align:start position:0% +10 R up + + align:start position:0% + + + + align:start position:0% + +feature wa we guys see what they + + align:start position:0% +feature wa we guys see what they + + + align:start position:0% +feature wa we guys see what they +are I'm already going to tell you uh no + + align:start position:0% +are I'm already going to tell you uh no + + + align:start position:0% +are I'm already going to tell you uh no +surprise these aren't going to work + + align:start position:0% +surprise these aren't going to work + + + align:start position:0% +surprise these aren't going to work +nearly as well as the ones we just made + + align:start position:0% +nearly as well as the ones we just made + + + align:start position:0% +nearly as well as the ones we just made +um note dens feature isn't going to help + + align:start position:0% +um note dens feature isn't going to help + + + align:start position:0% +um note dens feature isn't going to help +us very much I would have thought range + + align:start position:0% +us very much I would have thought range + + + align:start position:0% +us very much I would have thought range +might have told us something about a jig + + align:start position:0% +might have told us something about a jig + + + align:start position:0% +might have told us something about a jig +but maybe it's not um some people will + + align:start position:0% +but maybe it's not um some people will + + + align:start position:0% +but maybe it's not um some people will +tell you hey just throw lots of feature + + align:start position:0% +tell you hey just throw lots of feature + + + align:start position:0% +tell you hey just throw lots of feature +extractors in um it can't hurt it kind + + align:start position:0% +extractors in um it can't hurt it kind + + + align:start position:0% +extractors in um it can't hurt it kind +of can but because we often don't have + + align:start position:0% +of can but because we often don't have + + + align:start position:0% +of can but because we often don't have +enough data to make use of all these + + align:start position:0% +enough data to make use of all these + + + align:start position:0% +enough data to make use of all these +features but let's give it a shot we're + + align:start position:0% +features but let's give it a shot we're + + + align:start position:0% +features but let's give it a shot we're +going to add these feature + + align:start position:0% +going to add these feature + + + align:start position:0% +going to add these feature +extractors to um our training set and to + + align:start position:0% +extractors to um our training set and to + + + align:start position:0% +extractors to um our training set and to +to our testing + + align:start position:0% + + + + align:start position:0% + +set okay so our training set and testing + + align:start position:0% +set okay so our training set and testing + + + align:start position:0% +set okay so our training set and testing +set any uh is now ready to go where any + + align:start position:0% +set any uh is now ready to go where any + + + align:start position:0% +set any uh is now ready to go where any +stream we add to these sets we're going + + align:start position:0% +stream we add to these sets we're going + + + align:start position:0% +stream we add to these sets we're going +to um going to have these feature + + align:start position:0% +to um going to have these feature + + + align:start position:0% +to um going to have these feature +extractors added to them so we'll say is + + align:start position:0% +extractors added to them so we'll say is + + + align:start position:0% +extractors added to them so we'll say is +for I add metad dat entry in a + + align:start position:0% +for I add metad dat entry in a + + + align:start position:0% +for I add metad dat entry in a +numerate + + align:start position:0% +numerate + + + align:start position:0% +numerate +uh Ryan again P's part + + align:start position:0% +uh Ryan again P's part + + + align:start position:0% +uh Ryan again P's part +equals metad dat + + align:start position:0% +equals metad dat + + + align:start position:0% +equals metad dat +entry. + + align:start position:0% +entry. + + + align:start position:0% +entry. +parse if I is odd then training or test + + align:start position:0% +parse if I is odd then training or test + + + align:start position:0% +parse if I is odd then training or test +will be we'll we'll set um so we only + + align:start position:0% +will be we'll we'll set um so we only + + + align:start position:0% +will be we'll we'll set um so we only +have to write things once we'll set our + + align:start position:0% +have to write things once we'll set our + + + align:start position:0% +have to write things once we'll set our +training or test set will be the + + align:start position:0% +training or test set will be the + + + align:start position:0% +training or test set will be the +training set in this case otherwise our + + align:start position:0% +training set in this case otherwise our + + + align:start position:0% +training set in this case otherwise our +training or test will be our testing + + align:start position:0% +training or test will be our testing + + + align:start position:0% +training or test will be our testing +set great uh file name is the pie PAR + + align:start position:0% +set great uh file name is the pie PAR + + + align:start position:0% +set great uh file name is the pie PAR +file path name is jig same thing we were + + align:start position:0% +file path name is jig same thing we were + + + align:start position:0% +file path name is jig same thing we were +doing + + align:start position:0% +doing + + + align:start position:0% +doing +before here we're not going to um music + + align:start position:0% +before here we're not going to um music + + + align:start position:0% +before here we're not going to um music +21 smart enough it doesn't need us to + + align:start position:0% +21 smart enough it doesn't need us to + + + align:start position:0% +21 smart enough it doesn't need us to +cast this to an integer that'll figure + + align:start position:0% +cast this to an integer that'll figure + + + align:start position:0% +cast this to an integer that'll figure +out what to do itself + + align:start position:0% +out what to do itself + + + align:start position:0% +out what to do itself +okay we going say what row are we is + + align:start position:0% +okay we going say what row are we is + + + align:start position:0% +okay we going say what row are we is +this a jig and what's its file name + + align:start position:0% +this a jig and what's its file name + + + align:start position:0% +this a jig and what's its file name +that's easy part and then whatever + + align:start position:0% +that's easy part and then whatever + + + align:start position:0% +that's easy part and then whatever +dating data set we're working with + + align:start position:0% +dating data set we're working with + + + align:start position:0% +dating data set we're working with +training or test we're going to add + + align:start position:0% +training or test we're going to add + + + align:start position:0% +training or test we're going to add +the data from the here's a stream our + + align:start position:0% +the data from the here's a stream our + + + align:start position:0% +the data from the here's a stream our +score whatever you call it class value + + align:start position:0% +score whatever you call it class value + + + align:start position:0% +score whatever you call it class value +what is what is the right answer it's + + align:start position:0% +what is what is the right answer it's + + + align:start position:0% +what is what is the right answer it's +whether or not this is a jig and then + + align:start position:0% +whether or not this is a jig and then + + + align:start position:0% +whether or not this is a jig and then +the identification for this will be the + + align:start position:0% +the identification for this will be the + + + align:start position:0% +the identification for this will be the +file name okay boom it's going to go + + align:start position:0% +file name okay boom it's going to go + + + align:start position:0% +file name okay boom it's going to go +through it has 1,000 of these to run so + + align:start position:0% +through it has 1,000 of these to run so + + + align:start position:0% +through it has 1,000 of these to run so +I'm not going to wait for all of it to + + align:start position:0% +I'm not going to wait for all of it to + + + align:start position:0% +I'm not going to wait for all of it to +um happen I'm going to stop for a second + + align:start position:0% +um happen I'm going to stop for a second + + + align:start position:0% +um happen I'm going to stop for a second +um + + align:start position:0% +um + + + align:start position:0% +um +because we don't have all that time in + + align:start position:0% +because we don't have all that time in + + + align:start position:0% +because we don't have all that time in +the world um that's part of the reason + + align:start position:0% +the world um that's part of the reason + + + align:start position:0% +the world um that's part of the reason +why we also don't want to do everything + + align:start position:0% +why we also don't want to do everything + + + align:start position:0% +why we also don't want to do everything +but our that small training set we're + + align:start position:0% +but our that small training set we're + + + align:start position:0% +but our that small training set we're +going to process and we're going to take + + align:start position:0% +going to process and we're going to take + + + align:start position:0% +going to process and we're going to take +that training set and write it out to + + align:start position:0% +that training set and write it out to + + + align:start position:0% +that training set and write it out to +train + + align:start position:0% +train + + + align:start position:0% +train +to. no we're not you should do that + + align:start position:0% +to. no we're not you should do that + + + align:start position:0% +to. no we're not you should do that +because you have time to wait but uh + + align:start position:0% +because you have time to wait but uh + + + align:start position:0% +because you have time to wait but uh +nobody wants us do that we'll do the + + align:start position:0% +nobody wants us do that we'll do the + + + align:start position:0% +nobody wants us do that we'll do the +same thing with the testing set process + + align:start position:0% +same thing with the testing set process + + + align:start position:0% +same thing with the testing set process +and then testing set + + align:start position:0% +and then testing set + + + align:start position:0% +and then testing set +we're going to write that to test + + align:start position:0% +we're going to write that to test + + + align:start position:0% +we're going to write that to test +2.tap I'm not doing that right now + + align:start position:0% +2.tap I'm not doing that right now + + + align:start position:0% +2.tap I'm not doing that right now +because like they do in those old + + align:start position:0% +because like they do in those old + + + align:start position:0% +because like they do in those old +cooking shows um I've already done all + + align:start position:0% +cooking shows um I've already done all + + + align:start position:0% +cooking shows um I've already done all +this and I'm going to uh load it from + + align:start position:0% +this and I'm going to uh load it from + + + align:start position:0% +this and I'm going to uh load it from +what I've already done + + align:start position:0% +what I've already done + + + align:start position:0% +what I've already done +so um you know what I mean the old + + align:start position:0% +so um you know what I mean the old + + + align:start position:0% +so um you know what I mean the old +cooking shows where they put they put + + align:start position:0% +cooking shows where they put they put + + + align:start position:0% +cooking shows where they put they put +the turkey raw turkey in the oven and + + align:start position:0% +the turkey raw turkey in the oven and + + + align:start position:0% +the turkey raw turkey in the oven and +then they just immediately go to the + + align:start position:0% +then they just immediately go to the + + + align:start position:0% +then they just immediately go to the +other oven and the turkey son. sorry all + + align:start position:0% +other oven and the turkey son. sorry all + + + align:start position:0% +other oven and the turkey son. sorry all +right I you know you all can read my + + align:start position:0% +right I you know you all can read my + + + align:start position:0% +right I you know you all can read my +mind right that's that's + + align:start position:0% +mind right that's that's + + + align:start position:0% +mind right that's that's +what that's what you pay me to do make + + align:start position:0% +what that's what you pay me to do make + + + align:start position:0% +what that's what you pay me to do make +you read my mind to not actually + + align:start position:0% +you read my mind to not actually + + + align:start position:0% +you read my mind to not actually +teach that's fantastic um okay a no + + align:start position:0% +teach that's fantastic um okay a no + + + align:start position:0% +teach that's fantastic um okay a no +enough I'll make this line up so I + + align:start position:0% +enough I'll make this line up so I + + + align:start position:0% +enough I'll make this line up so I +don't so I don't make any + + align:start position:0% +don't so I don't make any + + + align:start position:0% +don't so I don't make any +typos on my + + align:start position:0% +typos on my + + + align:start position:0% +typos on my +desktop test 2.tap that's why it broke + + align:start position:0% +desktop test 2.tap that's why it broke + + + align:start position:0% +desktop test 2.tap that's why it broke +okay so again we're going to do + + align:start position:0% +okay so again we're going to do + + + align:start position:0% +okay so again we're going to do +everything as before why do everything + + align:start position:0% +everything as before why do everything + + + align:start position:0% +everything as before why do everything +as before when you can't just copy + + align:start position:0% + + + + align:start position:0% + +and because now we've already written + + align:start position:0% +and because now we've already written + + + align:start position:0% +and because now we've already written +everything out for um yeah this this + + align:start position:0% +everything out for um yeah this this + + + align:start position:0% +everything out for um yeah this this +whole process and right thing takes care + + align:start position:0% +whole process and right thing takes care + + + align:start position:0% +whole process and right thing takes care +of everything we did before where we + + align:start position:0% +of everything we did before where we + + + align:start position:0% +of everything we did before where we +where is that where we had to Define we + + align:start position:0% +where is that where we had to Define we + + + align:start position:0% +where is that where we had to Define we +had to open our datas we had to Define + + align:start position:0% +had to open our datas we had to Define + + + align:start position:0% +had to open our datas we had to Define +our columns we had to write that out + + align:start position:0% +our columns we had to write that out + + + align:start position:0% +our columns we had to write that out +Define our description write out all our + + align:start position:0% +Define our description write out all our + + + align:start position:0% +Define our description write out all our +meta things um extract write our feature + + align:start position:0% +meta things um extract write our feature + + + align:start position:0% +meta things um extract write our feature +extractors do all that + + align:start position:0% +extractors do all that + + + align:start position:0% +extractors do all that +stuff these little um process and then + + align:start position:0% +stuff these little um process and then + + + align:start position:0% +stuff these little um process and then +write did all that for us so now we're + + align:start position:0% +write did all that for us so now we're + + + align:start position:0% +write did all that for us so now we're +we're actually back on to + + align:start position:0% +we're actually back on to + + + align:start position:0% +we're actually back on to +uh uh feature extraction is + + align:start position:0% + + + + align:start position:0% + +done let's do machine learning anybody + + align:start position:0% +done let's do machine learning anybody + + + align:start position:0% +done let's do machine learning anybody +who tells you that the machine learn + + align:start position:0% +who tells you that the machine learn + + + align:start position:0% +who tells you that the machine learn +learning is the only hard part and that + + align:start position:0% +learning is the only hard part and that + + + align:start position:0% +learning is the only hard part and that +feature extraction uh is easy stuff uh + + align:start position:0% +feature extraction uh is easy stuff uh + + + align:start position:0% +feature extraction uh is easy stuff uh +is lying to you or is doesn't know what + + align:start position:0% +is lying to you or is doesn't know what + + + align:start position:0% +is lying to you or is doesn't know what +they're talking about or whatever + + align:start position:0% +they're talking about or whatever + + + align:start position:0% +they're talking about or whatever +because um feature extraction and doing + + align:start position:0% +because um feature extraction and doing + + + align:start position:0% +because um feature extraction and doing +it right is really really hard okay so + + align:start position:0% +it right is really really hard okay so + + + align:start position:0% +it right is really really hard okay so +we're going to cop basically copy and + + align:start position:0% +we're going to cop basically copy and + + + align:start position:0% +we're going to cop basically copy and +paste everything that um that we did + + align:start position:0% +paste everything that um that we did + + + align:start position:0% +paste everything that um that we did +before totals something like + + align:start position:0% +before totals something like + + + align:start position:0% +before totals something like +that great we're going to run this + + align:start position:0% +that great we're going to run this + + + align:start position:0% +that great we're going to run this +again and then we're going + + align:start position:0% +again and then we're going + + + align:start position:0% +again and then we're going +to print everything + + align:start position:0% + + + + align:start position:0% + +afterwards great and that's going to go + + align:start position:0% +afterwards great and that's going to go + + + align:start position:0% +afterwards great and that's going to go +through and uh it's going to print a + + align:start position:0% +through and uh it's going to print a + + + align:start position:0% +through and uh it's going to print a +couple things what are we + + align:start position:0% +couple things what are we + + + align:start position:0% +couple things what are we +doing oh has to we giving it a lot more + + align:start position:0% +doing oh has to we giving it a lot more + + + align:start position:0% +doing oh has to we giving it a lot more +things to train on so a lot more data + + align:start position:0% +things to train on so a lot more data + + + align:start position:0% +things to train on so a lot more data +these are much bigger files because of + + align:start position:0% +these are much bigger files because of + + + align:start position:0% +these are much bigger files because of +all the different feature extractors so + + align:start position:0% +all the different feature extractors so + + + align:start position:0% +all the different feature extractors so +it takes a while you can see in all this + + align:start position:0% +it takes a while you can see in all this + + + align:start position:0% +it takes a while you can see in all this +time it's just done one + + align:start position:0% +time it's just done one + + + align:start position:0% +time it's just done one +row and two rows are we going to wait + + align:start position:0% +row and two rows are we going to wait + + + align:start position:0% +row and two rows are we going to wait +for + + align:start position:0% +for + + + align:start position:0% +for +uh you know oh I think it's like an hour + + align:start position:0% +uh you know oh I think it's like an hour + + + align:start position:0% +uh you know oh I think it's like an hour +and a half and I ran this at like 2 in + + align:start position:0% +and a half and I ran this at like 2 in + + + align:start position:0% +and a half and I ran this at like 2 in +the morning are we going to wait an hour + + align:start position:0% +the morning are we going to wait an hour + + + align:start position:0% +the morning are we going to wait an hour +and a half we can all do that no I'm + + align:start position:0% +and a half we can all do that no I'm + + + align:start position:0% +and a half we can all do that no I'm +going to hit stop for a second on the + + align:start position:0% +going to hit stop for a second on the + + + align:start position:0% +going to hit stop for a second on the +recording and then I'm going to load up + + align:start position:0% +recording and then I'm going to load up + + + align:start position:0% +recording and then I'm going to load up +our + + align:start position:0% +our + + + align:start position:0% +our +results okay here are the results I + + align:start position:0% +results okay here are the results I + + + align:start position:0% +results okay here are the results I +got again our majority learner got 77% + + align:start position:0% +got again our majority learner got 77% + + + align:start position:0% +got again our majority learner got 77% +right and our K nearest neighbors super + + align:start position:0% +right and our K nearest neighbors super + + + align:start position:0% +right and our K nearest neighbors super +intelligent artificial + + align:start position:0% +intelligent artificial + + + align:start position:0% +intelligent artificial +intelligence only got 4% better I mean I + + align:start position:0% +intelligence only got 4% better I mean I + + + align:start position:0% +intelligence only got 4% better I mean I +don't even know if that meets the margin + + align:start position:0% +don't even know if that meets the margin + + + align:start position:0% +don't even know if that meets the margin +of error in a political poll or + + align:start position:0% +of error in a political poll or + + + align:start position:0% +of error in a political poll or +something so all that extra time didn't + + align:start position:0% +something so all that extra time didn't + + + align:start position:0% +something so all that extra time didn't +actually improve anything what's + + align:start position:0% +actually improve anything what's + + + align:start position:0% +actually improve anything what's +important is always to choose your um + + align:start position:0% +important is always to choose your um + + + align:start position:0% +important is always to choose your um +choose your + + align:start position:0% +choose your + + + align:start position:0% +choose your +feature extractors well the fact that I + + align:start position:0% +feature extractors well the fact that I + + + align:start position:0% +feature extractors well the fact that I +didn't include that one simple extractor + + align:start position:0% +didn't include that one simple extractor + + + align:start position:0% +didn't include that one simple extractor +about the time signature made all the + + align:start position:0% +about the time signature made all the + + + align:start position:0% +about the time signature made all the +difference in the world I think um okay + + align:start position:0% +difference in the world I think um okay + + + align:start position:0% +difference in the world I think um okay +I just want to show that there's um you + + align:start position:0% +I just want to show that there's um you + + + align:start position:0% +I just want to show that there's um you +can uh you can print all of the + + align:start position:0% +can uh you can print all of the + + + align:start position:0% +can uh you can print all of the +different features onto various charts + + align:start position:0% +different features onto various charts + + + align:start position:0% +different features onto various charts +and zoom in and stuff like that if + + align:start position:0% +and zoom in and stuff like that if + + + align:start position:0% +and zoom in and stuff like that if +people want to do that but that'll be + + align:start position:0% +people want to do that but that'll be + + + align:start position:0% +people want to do that but that'll be +something for another + + align:start position:0% +something for another + + + align:start position:0% +something for another +time this is what is available to you + + align:start position:0% +time this is what is available to you + + + align:start position:0% +time this is what is available to you +now um maybe not this kind of low-level + + align:start position:0% +now um maybe not this kind of low-level + + + align:start position:0% +now um maybe not this kind of low-level +one but using the these feature + + align:start position:0% +one but using the these feature + + + align:start position:0% +one but using the these feature +extractors simple ones like Sharps and + + align:start position:0% +extractors simple ones like Sharps and + + + align:start position:0% +extractors simple ones like Sharps and +meter and uh what was that percentage of + + align:start position:0% +meter and uh what was that percentage of + + + align:start position:0% +meter and uh what was that percentage of +compound time range features things like + + align:start position:0% +compound time range features things like + + + align:start position:0% +compound time range features things like +that in order to classify pieces is + + align:start position:0% +that in order to classify pieces is + + + align:start position:0% +that in order to classify pieces is +incredibly powerful and when put + + align:start position:0% +incredibly powerful and when put + + + align:start position:0% +incredibly powerful and when put +together with the right machine learning + + align:start position:0% +together with the right machine learning + + + align:start position:0% +together with the right machine learning +and artificial intelligence algorithm + + align:start position:0% +and artificial intelligence algorithm + + + align:start position:0% +and artificial intelligence algorithm +there's a lot of possibilities for the + + align:start position:0% +there's a lot of possibilities for the + + + align:start position:0% +there's a lot of possibilities for the +future of computational Music + + align:start position:0% +future of computational Music + + + align:start position:0% +future of computational Music +analysis this lecture is run pretty darn + + align:start position:0% +analysis this lecture is run pretty darn + + + align:start position:0% +analysis this lecture is run pretty darn +long so I'm going to say for a second + + align:start position:0% +long so I'm going to say for a second + + + align:start position:0% +long so I'm going to say for a second +little supplement on what are some of + + align:start position:0% +little supplement on what are some of + + + align:start position:0% +little supplement on what are some of +the things that I have learned through + + align:start position:0% +the things that I have learned through + + + align:start position:0% +the things that I have learned through +using computational artificial + + align:start position:0% +using computational artificial + + + align:start position:0% +using computational artificial +intelligence what are some of the + + align:start position:0% +intelligence what are some of the + + + align:start position:0% +intelligence what are some of the +projects other people have done and why + + align:start position:0% +projects other people have done and why + + + align:start position:0% +projects other people have done and why +the world of the-art blackbox deep + + align:start position:0% +the world of the-art blackbox deep + + + align:start position:0% +the world of the-art blackbox deep +learning or um other sophisticated + + align:start position:0% +learning or um other sophisticated + + + align:start position:0% +learning or um other sophisticated +algorithms might not always be the best + + align:start position:0% +algorithms might not always be the best + + + align:start position:0% +algorithms might not always be the best +ones that we want to use when we're + + align:start position:0% +ones that we want to use when we're + + + align:start position:0% +ones that we want to use when we're +doing artificial intelligence and + + align:start position:0% +doing artificial intelligence and + + + align:start position:0% +doing artificial intelligence and +machine learning techniques on musical + + align:start position:0% +machine learning techniques on musical + + + align:start position:0% +machine learning techniques on musical +scores but we'll leave that for another + + align:start position:0% +scores but we'll leave that for another + + + align:start position:0% +scores but we'll leave that for another +time thank you so much for listening go + + align:start position:0% +time thank you so much for listening go + + + align:start position:0% +time thank you so much for listening go +ahead and play around with some data + + align:start position:0% +ahead and play around with some data + + + align:start position:0% +ahead and play around with some data +sets you've learned how to use Corpus + + align:start position:0% +sets you've learned how to use Corpus + + + align:start position:0% +sets you've learned how to use Corpus +search to be able to find various pieces + + align:start position:0% +search to be able to find various pieces + + + align:start position:0% +search to be able to find various pieces +on there's a music 21 uh I think chapter + + align:start position:0% +on there's a music 21 uh I think chapter + + + align:start position:0% +on there's a music 21 uh I think chapter +users guide chapter and tutorial on how + + align:start position:0% +users guide chapter and tutorial on how + + + align:start position:0% +users guide chapter and tutorial on how +to do more interesting things with that + + align:start position:0% +to do more interesting things with that + + + align:start position:0% +to do more interesting things with that +there's the paper written with Chris ARA + + align:start position:0% +there's the paper written with Chris ARA + + + align:start position:0% +there's the paper written with Chris ARA +and Lisa Friedland on using feature + + align:start position:0% +and Lisa Friedland on using feature + + + align:start position:0% +and Lisa Friedland on using feature +extractors with music 21 and there's + + align:start position:0% +extractors with music 21 and there's + + + align:start position:0% +extractors with music 21 and there's +also some other um music 21 feature + + align:start position:0% +also some other um music 21 feature + + + align:start position:0% +also some other um music 21 feature +extractor papers that were written with + + align:start position:0% +extractor papers that were written with + + + align:start position:0% +extractor papers that were written with +MIT undergraduate europs on how we can + + align:start position:0% +MIT undergraduate europs on how we can + + + align:start position:0% +MIT undergraduate europs on how we can +use feature extraction to go beyond what + + align:start position:0% +use feature extraction to go beyond what + + + align:start position:0% +use feature extraction to go beyond what +we can do with midi to really look at + + align:start position:0% +we can do with midi to really look at + + + align:start position:0% +we can do with midi to really look at +the Nuance of musical scores in feature + + align:start position:0% +the Nuance of musical scores in feature + + + align:start position:0% +the Nuance of musical scores in feature +extraction I'll be sending all those + + align:start position:0% +extraction I'll be sending all those + + + align:start position:0% +extraction I'll be sending all those +around the meantime please go back + + align:start position:0% +around the meantime please go back + + + align:start position:0% +around the meantime please go back +through your the most interesting parts + + align:start position:0% +through your the most interesting parts + + + align:start position:0% +through your the most interesting parts +of this lecture to you hit pause and + + align:start position:0% +of this lecture to you hit pause and + + + align:start position:0% +of this lecture to you hit pause and +play around with your own data + + align:start position:0% +play around with your own data + + + align:start position:0% +play around with your own data +sense good luck in applying this to + + align:start position:0% +sense good luck in applying this to + + + align:start position:0% +sense good luck in applying this to +Future projects \ No newline at end of file diff --git a/fGUaxrIejr4.txt b/fGUaxrIejr4.txt new file mode 100644 index 0000000000000000000000000000000000000000..5452112480f79f2ca48ee1703714487bd4a73e39 --- /dev/null +++ b/fGUaxrIejr4.txt @@ -0,0 +1,2802 @@ +The following +content is provided + +under a Creative +Commons license. + +Your support will help MIT +OpenCourseWare continue + +to offer high quality +educational resources for free. + +To make a donation or +view additional materials + +from hundreds of MIT courses, +visit MIT OpenCourseWare + +at ocw.mit.edu. + +PROFESSOR: OK, let's start. + +So we've been trying to +understand critical points. + +And this refers to the +experimental observation + +that in a number +of systems we can + +be changing some parameters, +such as temperature, + +and you encounter a transition +to some other type of behavior + +at some point. + +So the temperature, let's +say, in this behavior + +is the control parameter. + +And you have to +see, for example, + +this will be normal to +superfluid transition. + +You have one now [INAUDIBLE] +change temperature and going + +through this point. + +For other systems, +such as magnets, + +you actually have two knobs. + +There is also the +magnetic field. + +And there, you have +to turn two knobs + +in order to end at +this critical point, + +also in the case of the liquid +gas system in the pressure + +temperature plane, you +have to tune two things + +to get this point. + +And the interesting thing +was that in the vicinity + +of his point, the singular +parts of various thermodynamic + +quantities are interestingly +independent of the type + +of material. + +So if we, for example, establish +a coordinate at t and h + +describing deviations +from this critical point, + +we have, let's say, +the singular part + +of free energy as a +function of t and h + +has a form like t to +the 2 minus alpha, + +some scaling function +ht to the delta, + +and these exponents, alpha +and delta, other things + +that are universe. + +For example, we +could get from that + +by taking two derivatives with +respect to h, the singularity + +and the divergence of +the susceptibility. + +And we said that the +diverging susceptibility also + +immediately tells you that +there is a correlation then + +that diverges, and +in particular, we + +indicated its divergence +to an exponent u. + +WE could for that also +establish a scaling form + +on how the correlation +then diverges + +on approaching this point +generally in the ht plane. + +So this was the general picture. + +And building on that, we made +one observation last time, + +which is that any point when +you are away from h and t + +equals to 0, you have +a correlation length. + +And then we concluded that if +you are at t and h equals to 0, + +you have a form of +scaling vertices. + +And basically what +that means is that when + +you are at that point, +you look at your system, + +it's a fluctuating system, +and the fluctuations are + +such that you can't +associate a scale with them. + +The scale has already +gone into the correlation + +length that is infinite. + +And we said that +therefore, if I were + +to look at some kind of +a correlation function, + +such as a magnetization +in the case of a magnet, + +that the only way that +it became its separation + +is as a power of a distance. + +And this clearly has +a property that if we + +were to rescale x and +y by a certain amount, + +this correlation function +nearly gets multiplied + +by a factor that is +dependent on this rescale. + +And this is after +we do the averaging, + +so it's a kind of +statistical self-singularity, + +as opposed to some factor such +as Sierpinkski gasket, which + +are identically and +deterministically + +self-similar in that each +piece, if you blow it up, + +looks like the entire thing. + +So what we have in our system +is that if we have, let's say, + +a box which could be +containing our liquid gas + +system at its critical +point, or maybe a magnet + +at its critical point, will +have a statistical field, + +this m of x. + +And it will fluctuate +across the system. + +So maybe this would be a picture +of the density fluctuation. + +What I can do is to take a scan +along some particular axis-- + +let's call it x-- and plot +what the fluctuations are + +of this magnetization. + +Let's say m of x. + +Now the average +will be 0, but it + +will have fluctuations +around the average. + +And so maybe it +will look something + +like this-- kind of like +a picture of a mountain, + +for example. + +Now one thing that +we should remember + +is that this object would +be piece of iron or nickle, + +and clearly I don't +really mean that this + +is what is going on at +the scale of a single atom + +or molecule of my substance. + +I had to do some kind +of averaging in order + +to get the statistical field +that I'm presenting here. + +So let's keep in +mind that there is, + +in fact, some implicit +analog of lattice size + +or some implicit +shortest distance, + +shortest wavelength that I +allow for my frustrations. + +Now I can sort of make this +idea of scale invariance + +of a set of pictures, such +as this one, more precise, + +as follows, by going +through a procedure + +that I will call renormalization +that has the following three + +steps. + +So the first step, what I will +do is to coarse-grain further. + +And by this, I mean averaging +m of x over a scale ta. + +So previously, I had done my +averaging of whatever means, + +et cetera. + +We're giving contribution +to the overall magnetization + +over some number, +let's 100 by 100 by 100 + +spins and a was my +scaling distance. + +Why should I choose 100? + +Why not choose 200, some factor +of what I had originally? + +So coarse-graining means +increasing this minimum length + +scale from a to ba. + +And then I define a +coarse-grained version + +of my field. + +So previously, I had m of x. + +Now I have m tilda of x, which +is obtained by averaging, + +let's say, over volume around +the point x that I had before. + +And this volume is a box +of dimension ba to the d. + +And then I basically +average over that. + +I guess let's call it +original distance a equals 1, + +so I don't really have to bother +by the dimensionality of y, + +et cetera. + +OK? + +So if I were to apply +that to the picture + +that I have up +there, what do I get? + +I will get an m tilda +as a function of x. + +And essentially, +let's say if I were + +to choose a factor +of b that was like 2, + +I would take the average +of the fluctuations + +that they have over 2 of +those of those intervals. + +And so the picture +that I would get it + +would be kind of a +smoothened out version + +of what I have +before over there. + +I will still have +some fluctuations, + +but kind of ironed out. + +And basically, +essentially, it means + +that if you were to imagine +having taken a photograph, + +previously you had the +pixel size that was 1. + +Now your pixel size is larger. + +It is factor of b. + +So it's this kind of +detuning and averaging + +of the fluctuations +that has gone. + +And so you have here now b. + +Now if I were to give you +a photograph like that + +and a photograph +like this, you would + +say that they are not identical. + +One of them is clearly much +grainier than the other. + +So I say, OK, I can restore +some amount of similarity + +between them by +doing a rescaling. + +So I call a new variable x prime +to be my old variable x divided + +by a factor of b. + +So when I do that +to this picture, + +I will get m tilda as +a function of x prime. + +x prime can go in further +less, because all I do + +is I take this and squeeze +it by a factor of b. + +So I will get a +picture that maybe + +looks something like this. + +Now if I were to look at this +picture and this picture, + +you would also see a difference. + +That is, there is a contrast. + +So here, there would be, +let's say, black and white. + +And as you scan the +picture, you sort of see + +some variation of +black and white. + +If you look at this, you say +the contrast is just too big. + +You have big fluctuations +as you go across + +compared to what +I had over there. + +So there's another step, which +is called renormalize, which + +is that you define +m prime to be m + +by a change of +contrast factor zeta. + +So you take a knob that +corresponds to contrast + +and you reduce it +until you see pictures + +that kind of statistically look +like what you started with. + +So in order to sort of generate +pictures that are self-similar, + +you have this one knob. + +Basically, scaling variance +means the change of size. + +But there is associated +with change of size + +a change of contrast +for whatever variable + +you are looking at. + +It turns out that that +change of contrast + +would eventually map to +one of these exponents + +that we have over there. + +Yes. + +STUDENT: Are you +using m or n tilda? + +PROFESSOR: m tilda, thank you. + +So I guess the green +is m tilda of x prime, + +and the pink is m +prime of x prime. + +So what I have done +mathematically is as follows. + +I have defined an +m prime of x prime, + +which is 1 over zeta, +this contrast factor + +b to the d because of the +averaging over a volume + +that involved b to the d pixels +of the original field centered + +at a location that +was bx prime plus y. + +So in principle, I +can go and generate + +lots and lots of configurations +of my magnetization, + +or lots and lots of pictures +of a system at the liquid gas + +critical point, or +magnetic systems + +at their critical point. + +I can generate lots and +lots of these pictures + +and construct this +transformation. + +And associated with +this transformation + +is a change of +probability, because there + +was some probability-- +let's call it P old, + +that was describing my +original configurations m of x. + +Let's forget the vector +notation for the time being. + +Then there will be, after this +transformation, probability + +that describes these +configurations m + +prime of x prime. + +Now you know that +averaging is not something + +that you can reverse. + +So this transformation +going from here and here, + +I cannot go back. + +There are many +configurations over here + +that would correspond +to the same average, + +like up, down or down, +up would give you + +the same average, right? + +So a number of +possibilities here + +have to be summed up to +generate for you this object. + +Now the statement of +self-similarity presumably + +is that this weight is +the same as this weight. + +You can't tell apart that +you generated configurations + +before or after that scaling. + +So this is same +at critical point. + +I've not constructed +either weight, + +so it really doesn't +amount to much. + +But Kadanoff +introduced this concept + +of doing this and thinking of +it as a kind of group operation + +called renormalization +group that I + +describe a little bit better +and evolve the description as we + +go along. + +So if I look at my +original system, + +I said that +self-similarity occurs, + +let's say, exactly at this +point that corresponds to t + +and h equals to 0. + +Now presumably, I +can, in some sense, + +force these things, if I were +to take its log, for example. + +I can construct some +kind of a weight that + +is associated with +m, and this would + +be a new weight that is +associated with m prime. + +Presumably, right at +the critical point, + +these two would be +the same weight, + +and it would be the +same Hamiltonian. + +What happens, if I +do this procedure, + +to a system that is initially +away from the critical point? + +So my initial system is +characterized by deviations t + +and h from this scale +in variant ways, which + +means that over here I +have a correlation length. + +Now I go through all of +these transformations. + +I can do those +transformations also + +for a point that is not +at the critical point. + +But at the end of +the day, I certainly + +will not get back +my original weight, + +because I look at the picture +after this transformation. + +Before the transformation, I +had a long correlation length, + +let's say a mile. + +When I do this transformation, +that correlation length + +is reduced by a factor of b. + +So the new system has deviated +more from the critical point. + +Because the further you go +away from the critical point, + +you have a larger +correlation length. + +So the idea is that right +at the critical point, + +the two weights are the same. + +Deviation from +the critical point + +is described by these +two parameters, t and h. + +And if you do the +renormalization procedure + +on a Hamiltonian +that deviates, you + +will get a Hamiltonian +that more deviates, still + +describable by parameters +t and h that have changed. + +So again, this says +that c was, in fact, + +b times c of t +prime and h prime, + +and t prime and h +prime are further away. + +Now the next thing that Kadanoff +said was, OK, therefore there + +is a transformation +that tells me + +after I do a rescaling +by a factor of b how + +the new t and the new h depend +on the old t and the old h. + +So there is a mapping +in this space. + +So a point that was +here will go over there. + +Maybe a point that is +here will map over there. + +A point that is here +will map over here. + +So there is a mapping +that tells you + +how th get transformed +under this procedure. + +Actually the reason this is +called a renormalization group, + +groups we are really +thinking usually + +in terms of operations +that are invertible. + +This transformation +is not invertible. + +But this is a mapping. + +So potentially this +mapping is invertible. + +You can say that if this +point came from this point + +under inversion, it will go +back to the original point, + +and so forth. + +The next part of the argument +is what did we do over here? + +We got rid of some short +wavelength fluctuations. + +Now one of the things that I +said right at the beginning + +was that as long as you are +getting rid of short scale + +fluctuations, you are summing +over a cube that his 100 + +square, 200 cube. + +It doesn't matter, +100 cube, 200 cube-- + +you are doing some +analytical function. + +So the transformation +that relates these + +to these, the old to new, +should be analytical, + +and hence you should be able to +write a Taylor series for it. + +So let's try to make a +Taylor series for this. + +Taylor series start +with a constant. + +But we know that the constant +has to be 0 in both cases + +because the starting +point was the point that + +was scale invariant and +was mapping onto itself. + +So the first thing that I can +write down are linear terms. + +So there could be a term +that is proportional to t. + +There could be a term +that is proportional to h. + +There could be a term here +that is proportional to h. + +There could be a term +that is proportional-- + +well, let's call this t. + +Let's call this h. + +And then there +will be terms that + +will be order of t +squared and higher. + +So I just did an +analytical expansion, + +justified by this summing over +just finite degrees of freedom + +at short scale. + +Now if I have a structure, +such as the one that I + +have over there, I +also know some things + +on the basis of symmetry. + +Like if I'm on the line that +corresponds to h equals to 0, + +there is no difference +between up and down. + +Under rescaling, I still +don't know the difference + +between up and down. + +So I should not generate +an h if h was originally 0 + +just because t deviated from 0. + +So by symmetry, that +has to be absent. + +And similarly, by +symmetry, there + +is no difference between +h positive and h negative. + +As far as t is concerned, h and +minus h should behave the same. + +So this series should start at +order of h squared and not h, + +so that term should be absent. + +So at this level, we have a nice +separation into t prime is at + +and h Prime. + +Is dh. + +Now we know +something more, which + +is that the procedure +that we are doing + +has some kind of a group +character, in that if I, + +let's say, originally +transform by some factor b1, + +change by a factor of 2, +then change by a factor of 3, + +the answer is equivalent to +changing by a factor of 2 + +times 3, or 3 times 2. + +Doesn't matter in +which order I do them. + +So also, I would get, +if I were to do b1 first + +and b2 later, it would +be the same thing. + +So what does that imply? + +That if I do two of +these transformation, + +I find that my new t is obtained +in one case by the product, + +in the other case by the +product of the two a's. + +So that's, again, some +kind of a group character. + +And furthermore, if I don't +change the length scale, + +everything should +stay where it is. + +So you glance at +those, and you find + +that there is only +one possibility, + +that a as a function of b +should be b to some power. + +So you know therefore +that at the lowest + +order under rescaling +by a factor of b, + +t prime should be b +to some y-- I called + +it yt-- times t +plus higher orders, + +while h prime is b to some other +power of yh times h plus higher + +orders. + +And you say, OK, fine. + +What's this good for? + +Well, let's take a look +at what we did over there. + +We said that I take some bunch +of initial configurations, + +sum their weights +to get the weight + +of the new configuration. + +What happens if I sum over +all initial configurations? + +Well, if I sum over all +initial configuration, + +I will get the +partition function. + +Now essentially, +all the original + +configurations I +regrouped and put + +into these coarse-grained +configurations that + +are weighted this way. + +So there could be +an overall constant + +that emerges from this. + +But this really implies that +the singular part of log z, + +and presumably this +depends on how far + +away I am from the +critical point, + +is the same as log z that +singular after I do this t + +prime and h prime. + +Now there is one other +issue, which is extensivity. + +Up to signs, factors +of beta, et cetera, + +this is b times an +intensive free energy, + +which is a function of t and h. + +So this is the same as v prime, +because the volume shrunk. + +I took all of my scales and +shrunk it by a factor of v, + +v prime, f of t +prime and h prime. + +So now let's go this way. + +Note that v prime is +the original v divided + +by b to the d scaling factor. + +So you do the +divisions here, and you + +find that f as a +function of t and h + +is the ratio of v prime to +v, which is b to the minus d, + +f as a function of +t prime and h prime. + +But t prime we said to lowest +order is b to the yt t. + +h prime is b to the yh h. + +This is actually the +more correct form + +of writing a +homogeneous function. + +So previously in +last lecture, we + +assumed that the free energy +had a homogeneous form. + +Now subject to these +conditions and assumptions + +of renormalization +group, we have + +concluded that it should +have that homogeneous form. + +Now you say this +homogeneous form does not + +look like the +homogeneous forms that I + +had written for you before. + +I say, OK. + +Presumably this is true +for any factor of b + +that I want to choose. + +Let me choose a b, a rescaling +factor such that v to the yt t + +is of the order of 1. + +Could be 1, could be pi. + +I don't care. + +Which means that +I chose a factor + +of b that will scale with t +as t to the minus 1 over yt. + +I put this b-- this expression +is true for all choices of b. + +If I chose that particular +value, what I get + +is t to the d over +yt, some function. + +First argument has now +become 1 or some constant. + +Really it only depends +on the second argument + +in the combination h and t +to the power of yh over yt. + +So you can see that +this is, in fact, + +the same as the first +line that I have above. + +And I have identified +that 2 minus alpha + +would be related to +this factor of yt, which + +is how you would scale +under renormalization, + +the parameters t and h. + +And the gap exponent is related +to the ratio of yh over yt. + +Similarly, we had that +the correlation length-- + +I have a line there. + +Psi of t and h is b psi +of t prime and h prime. + +So I have that psi as +a function of t and h + +is b times psi as a function of +b to the yt t, b to the yh h. + +So that's also correct. + +I can again choose this value +of v, substitute it over there. + +What do I get? + +I get that psi as a +function of t and h + +would be t to the +minus 1 over yt, + +some scaling function-- let's +call it g psi-- of, again, h + +to the power of yh over yt. + +So I have got an answer +that nu should be 1 over yt. + +I can get the scaling form +for the correlation length. + +I identify the divergence +of correlation length + +with inverse of this. + +And by the way, I get, if I +substitute nu as 1 over yt + +here, the Josephson hyperscale +in relation to minus alpha + +equals to b. + +I can go further if I want. + +I can calculate magnetization +as a function of t and h, + +would correspond to +basically the behaviors + +that we identify with exponents +beta or delta as d log z. + +Yeah, let's say f by dh. + +If I take a +derivative over there, + +you can immediately +see that what + +that gives me is b to the +power of yh minus d, and then + +some scaling function which is +the derivative of this scaling + +function b the yt +t, b to the yh h. + +And again, if I +make this choice, + +then this goes over to t to the +power of d minus yh over yt, + +and then some scaling +function of h t to the delta. + +So I can continue with my table. + +And for example, +I will have beta + +to be d minus yh divided by yt. + +I can go and calculate +delta, et cetera. + +Actually I was a +little bit careless + +with this factor +zeta, which presumably + +is implicit in all of these +transformations that I have. + +And I have to do special +things to figure out + +what zeta is so that I will +get self-similarity right + +at the critical point. + +But we can see that +already we have + +the analog of a rescaling for m. + +And so it is easy to sort of +look at those two equations + +and identify that my zeta +should be precisely this one. + +So the zeta is not +independent of the relevance + +of the magnetic field. + +And if you think about it, the +field and the magnetization + +are conjugate variables in the +sense that in the weight here, + +I will have a term that is like +hm-- integrated, of course. + +And so hm integrated, +you can see + +that up to a factor of b +to the d from integration, + +the dimensionality that I assign +to h and the dimensionality + +that I assign to m +should be related. + +And not only for +the magnetization, + +but for any pair of variables +that are so conjugate-- + +there's some f, and +there's some x-- + +there will be a corresponding +relation between what + +would happen to this x at the +critical point and this factor + +f when I deviate from +the critical point. + +So all of this is +kind of nice, but it's + +a little bit hand waving. + +I essentially traded one set of +assumptions about homogeneity + +and scaling of free +energy correlation length + +to some other set of assumptions +about two parameters moving + +away from a scale +invariant critical point. + +I didn't calculate anything +about what the scale invariant + +probability is. + +I didn't show that, indeed, +two parameters are sufficient, + +that this kind of scaling +takes place, et cetera. + +So we need to be +much more precise + +if we want to do, ultimately, +calculations that give us + +what these numbers +yt and yh are. + +So let's try to put +this hand waving + +on a little bit +more firm setting. + +So let's see how +we should proceed. + +We start with some experimental +system, critical point. + +So I tell you that somebody in +the experiment, the liquid gas + +system, they saw a diverging +correlation length, + +critical opalescence, et cetera. + +So then I associate +with that some kind + +of a statistical field. + +And let's kind of +stick with the notation + +that we have for the magnet. + +Let's call it m of x. + +And in general, this +would be the part + +where one needs to put +in a lot of thinking. + +That is, the experimentalist +comes and tells you + +that I see a system that +undergoes a phase transition. + +There are some +response functions + +that are divergent, et cetera. + +You have to put in some +thinking to think about what + +the appropriate +order parameter is. + +And based on that order +parameter or statistical field, + +you construct the most +general weight consistent + +with symmetries, with +not only asymmetries + +but the kind of assumptions that +we have been putting in play. + +So we put in assumptions +about locality, symmetry. + +Stability is, of +course, paramount. + +But there is a list of things +that you have to think about. + +So once you do +that you say, OK, I + +associate with my +configurations m of x some set + +of probabilities. + +Probabilities are +certainly positive. + +So I can take its log, call its +minus its log to be some kind + +of a weight, beta h, that +governs these m of x's. + +If I say that I'm +obeying locality, + +then I would write the answer, +for example, like this. + +But it doesn't have to be. + +I have to write some +particular example. + +But you may construct +your example + +depending on the +system of interest. + +And let's say we are looking +at something like a superfluid, + +maybe, that we don't even have +the analog of magnetic field, + +and we go and +construct terms that + +are symmetric and made +for a two component m. + +And I will write a +few of these terms + +to emphasize that this is, +in principle, a long list. + +There's coefficient +of m to the sixth. + +We saw that the gradient +terms could start with this k. + +But maybe there's a +higher order gradient, + +and there's essentially +and infinity of terms + +that you can write down that +are consistent with these + +assumptions that you +have made so far. + +So you say, OK. + +Now I take this, and implicit +in all of these calculations + +is, indeed, some kind +of a short scale cutoff. + +To construct the +statistical field, + +I do apply the three steps of +RG-- renormalization group, + +as I described before. + +And this will give me +a new configuration + +for each of the +old configurations + +through the formula that +I gave you over there. + +So in principle, this is just +a transformation from one + +set of variables to a +new set of variables. + +So if I do this +transformation, I + +can calculate the weight +of the new configurations, + +m prime of x prime. + +I can take minus +the log of that. + +And again, up to +some constant, it + +will be the same +as a probability. + +So there could be, +in this procedure, + +some set of constants +that are generated + +that don't depend on m. + +And then there +will be a function + +that depends on m +prime of x prime. + +Now the statement +is that since I + +wrote the most general function +over here, whatever I put here + +will have to have exactly +the same form, because I said + +put anything that +you can think of that + +is consistent with +symmetries over here. + +So you put everything there. + +What I put here should have +exactly the same functional + +form, but with coefficients +that have changed. + +So you basically +prime everything, + +but you have this whole thing. + +Now this may seem like +truly difficult thing. + +But we will actually do this. + +We will carry out this +transformation explicitly + +in particular cases. + +And we will show that this +transformation amounts + +to constructing a rescaling of +each one of these parameters-- + +t prime, u prime, v prime, k +prime, l prime, and so forth-- + +as functions of +the old parameters. + +So this is, if you +like, a mapping. + +You take some set of +parameters-- t, u, v, k, l, + +blah, blah, blah-- and +you construct a mapping, + +s prime, which is some +function of the original set + +of parameters. + +So this is a huge +dimensional space. + +Any points that you start +on the transformation + +will go to another point. + +But the key is that we +wrote the most general form + +that we could, so we had +to stay within this space. + +So why are you doing this? + +Well, I started by saying that +the key to this whole thing + +is have to having a handle as +to what this self-similar scale + +invariant probability is. + +I can't construct +that just by guessing. + +But I can do what we +usually do, let's say, + +in constructing wave functions +in quantum mechanics that + +have some particular symmetry. + +Maybe you start with +some wave function that + +doesn't have the full +symmetry, and then + +you rotate it and +rotate it again, + +and you average +over all of them, + +and you end up with +some function that + +has the right symmetry. + +So we start with a +weight that I don't + +know whether it has the +property that I want. + +And I apply the action +of the group, which + +is this scaling +variance, to see what + +happens to it under +that transformation. + +But the point that +I am interested, + +or the behavior that +I am interested, + +is where I basically get +the same probability back. + +So I'm very interested +at the point where, + +under the transformation, +I go back to myself. + +And that's called a fixed point. + +So S is a shorthand for this +infinite vector of parameters. + +I want to find the point s +star in this parameter space. + +Actually, let me call +this transformation R + +and indicate that I'm +renormalizing by a scale b, + +such that, when I +renormalize by a scale + +b, my original +set of parameters, + +if I am at this fixed point, +I will end up at that point. + +So clearly, this +is a system that + +has exactly these properties +that I was harping in + +at the beginning. + +This is the point that +is truly scale invariant. + +That's the point that +I want to get at. + +So again, once we have +done this transformation + +in a specific case, we'll figure +out what this fixed point is. + +But for the time being, +let's think a little bit away + +from this and deviate +from fixed point. + +So I start with +an initial point S + +that is, let's write it, S +star plus a little bit away. + +Just like in the +picture that I have + +here, I started +with a fixed point, + +and I said I go +away by an amount + +that I had parameterized +by t and h. + +Now I have essentially +a whole line + +of deviations forming a vector. + +I act with Rb on this, and I +note that if delta S goes to 0, + +then I should go back to S star. + +But if delta S is +small, maybe I can + +look at the delta +S prime, which is + +a linearized version of +these transformations. + +So basically these +transformations + +are highly nonlinear just as +the transformation over here, + +in principle, would have +been highly nonlinear. + +But then I expanded it around +the point t and h equals to 0. + +Similarly, I'm assuming +that this delta S is small, + +and therefore delta S prime +can be related to delta S + +through the action of a matrix +that is a linearized version. + +Let's call it here RL of b. + +So this is a linearized +transformation, + +which means that +it's really a matrix. + +In this particular case, in +principle, I started with a 2 + +by 2 matrix. + +The off diagonal +terms were 0, so it + +was only the diagonal +terms that mattered. + +But in general, it +would be a matrix, + +which would be the +square of whatever + +the size of the parameter +space is that I am looking at. + +Now then you have +a matrix, it's good + +always to think in terms of its +eigenvalues and eigendirection. + +In this problem that +I had over here, + +symmetries had already +diagonalized the matrix. + +I didn't have off +diagonal terms. + +But I don't know here. + +It could be all kinds +of off diagonal terms. + +So the properties are +captured by diagonalize, RL, + +which means that I find a set +of vectors in this space-- + +let's call them Oi-- such +that under action of this, + +I will get lambda Oi, lambda i. + +Of course, the transformation +depends on the rescaling + +parameter, so there +should be a b here. + +Now of course, you will get +a totally different matrix + +for each b. + +So is it really hopeless that +for each b I have to look + +at a new matrix, new +diagonalization, et cetera? + +Well, exactly this thing +that we had over here + +now comes into +play, because I know + +that if I make a +transformation size b1 followed + +by a transformation size b2, +the answer is a transformation + +size b1, b2. + +And it doesn't matter +in which order I do it. + +AUDIENCE: Can't you just mix +notation, because L used to be + +[INAUDIBLE]? + +PROFESSOR: Sorry. + +So in particular, I see +that these linearized + +matrices commute with each +other for different values of b. + +And again, from your +quantum mechanics, + +you probably know that +if matrices commute then + +they have the same eigenvectors. + +So essentially, I was correct +here in putting no index b + +on these eigenvectors, +because it's + +independent of eigenvector, +whereas the eigenvalues, + +in principle, depend on b. + +And how they depend on +b is also determined + +by this transformation, that is +lambda i of b1, lambda i of b2 + +should be the same +thing as lambda b1, b2. + +And of course, lambda +i of 1 should be 1. + +If you don't change scale, +nothing should change. + +And this is exactly the +same set of conditions + +as we have over +here, which means + +that we know that the +eigenvalue's lambda i can + +be written as b to the +power of some set of yi. + +So we just generalized +what we had done before, + +now to this space that +includes many parameters. + +So the story is now +something like this. + +There is this +multi-dimensional space + +with lots and lots +of parameters-- + +t, u, v, blah, blah, +blah, many of them. + +And somewhere in this space +of parameters, presumably + +there is a fixed point, S star. + +Now in the vicinity +of that S star, + +I have established that there +are some particular directions + +that I can obtain by +diagonalizing this. + +So let's imagine that +this is one direction, + +this is another direction, +this is a third direction. + +And that if I start +with a beta h-- well, + +actually, let's do this. + +That is, if I start with an S +that is S star plus whatever + +is a projection of +my components are + +along these different +dimensions, so let's call them, + +let's say, ai along +these Oi hat-- just + +make sure we kind of +think of them as vectors-- + +that under rescaling, +I will go to S + +prime, which is S star plus +sum over i, ai b to the yi Oi. + +That is, some of +these directions, + +the component will get +stretched if yi is positive. + +It will get diminished +if yi is negative. + +And so now some notation +comes into play. + +If yi is positive, the +corresponding direction + +is called relevant. + +Eigendirection is relevant. + +If yi is negative, the +corresponding eigendirection + +is irrelevant. + +And very occasionally, +we may run into the case + +where yi is 0. + +And there is a terminology. + +The corresponding +eigendirection is marginal. + +And what that means is that I +need to resort to higher order + +terms to see whether it +is attracted or repelled + +by the fixed point. + +So we need higher orders. + +After all, so far I have only +linearized the transformation. + +Now the set of irrelevant +directions to this particular S + +fixed point, S star, defines +basing of attraction of S star. + +So let me go back to the +picture that I have over here + +and be precise and use the arrow +going away as an indication + +that the corresponding +b is positive, + +and I'm forced out +along this direction. + +Let me choose going +in as an indicator + +that the corresponding +y is negative. + +And as I make b +larger and larger, + +I shrink along this axis. + +So in this three +dimensional representation + +that I have over there, I have +one relevant direction and two + +irrelevant directions. + +The two irrelevant directions +will define the plane + +in this three +dimensional space, which + +is the basing of attraction. + +So basically these +two define a surface, + +and presumably any point that +is in this surface in the three + +dimensional picture +under looking + +at larger and larger +things will get + +attracted to the fixed point. + +If you are away +from the surface, + +maybe you will approach +here, and then you + +will be pushed out. + +All right, fine. + +Now let's go and look +at the following. + +We have a formula, +psi of t and h. + +Or quite generally, +psi under rescaling + +is b times the new psi. + +Or the new psi under any one +of these transformation, psi + +prime, is the old psi divided +by the old correlation + +length divided by a factor of b. + +So if I look at +the fixed point-- + +so if I ask what is psi +at the fixed point-- + +then under the transformation, +I have the same parameters. + +So psi at the fixed +point should be + +the psi of the fixed +point divided by b. + +There are only two +solutions to this. + +Either psi of S star is 0 or +psi of S star is infinite. + +Now we introduce physics. + +Psi being 0 means +that I have units + +that are completely +uncorrelated to each other. + +Each one of them does +whatever it wants. + +So this describes +essentially, let's say, + +a system of infinite +temperature. + +Every degree of freedom +does whatever it wants. + +Well, I should say this +corresponds to disordered + +or ordered phases. + +Because after all, +we said that when + +we go to the +ordered states also, + +there is an overall +magnetization, + +but fluctuations around +the overall magnetization + +have only a finite +correlation length. + +And as you go further and +further into the ordered phase, + +that correlation +length shrinks to 0. + +So there is a similarity +between what goes on + +at very high +temperature and what + +goes on at very +low temperature as + +far as the correlation of +fluctuations is concerned. + +There is, of course, +a long range order + +in one case that is +absent in the other. + +But the correlation +of fluctuations + +in both of those cases +basically becomes + +finite, and under rescaling, +goes all the way to 0. + +And clearly this is +the interesting case, + +where it corresponds +to critical point. + +So we've established that, +once we found this fixed point, + +that those set of parameters +are what can give us the scale + +invariant behavioral +that we want. + +Now this list is +hundreds of parameters. + +So this point corresponds +to a very special point + +in this hundreds +of parameter space. + +So let's say there is one +point somewhere there which + +is the fixed point. + +And then you take +your magnet and you + +change your critical +temperature, + +are we going to hit that point? + +The answer is, no. + +Generically, you are not +going to hit that point. + +But that's no problem. + +Why? + +Because if this +basing of attraction. + +Because for any point on basing +of attraction, I do rescaling, + +and I find that psi +prime is psi over b. + +It becomes smaller. + +So you generically +tend to become smaller. + +But ultimately, you +end up at this point. + +And this point, the +correlation length is infinite. + +So any point on this basing +of attraction, in fact, + +has infinite correlation length. + +So every point on the basis +of psi prime equals to psi, + +and hence psi has +to be infinite. + +Yes. + +AUDIENCE: Question. + +Why should there be +only one fixed point? + +PROFESSOR: There is no reason. + +AUDIENCE: OK. + +So this is just an example? + +PROFESSOR: Yeah. + +So locally, let's say that +we found such a fixed point. + +Maybe globally, there +is hundreds of them. + +I don't know. + +So that will always be +a question in our minds. + +So if I just write down for +you the most general set + +of transformations, who +knows what's happening? + +Ultimately, we have to +be guided by physics. + +We have to say that, if in the +space of all parametrization, + +there are some that have +no physical correspondence, + +we throw them out, +we seek things + +that can be matched to +our physical system. + +Yes? + +AUDIENCE: If there are +multiple fixed points, + +do the planes of the +basing of attraction + +have to be parallel +to each other? + +PROFESSOR: They may have +to have some conditions + +on non-intersecting or whatever. + +These are only linear in the +vicinity of the fixed point. + +So in principle, they could +be highly curved surfaces + +with all kinds of structures +and things that I don't know. + +Yes? + +AUDIENCE: Is there any reason +why you might or might not + +have attracting point +that is actually + +a more complicated +structure, like say, + +a limit cycle or +even a [INAUDIBLE]? + +PROFESSOR: Yeah. + +So again, we are governed +ultimately by physics. + +When I write these +equations, they + +are as general as equations as +the people in dynamical systems + +use that also includes +cycles, chaotic attractors, + +all kinds of strange things. + +And we have to hope that +when we apply this procedure + +to an appropriate +physical system, + +the kind of +equations that we get + +are such that their behavior +is indicative of the physics. + +So there is one case I know +where people sort of found + +chaotic renormalization +group trajectories + +for some kind of a +[INAUDIBLE] system. + +But always, again, this is +a very general procedure. + +We have to limit +mathematics, ultimately, + +by what the physical process is. + +So it's good that you know +that these equations can + +do all kinds of strange things. + +But then we take a +particular physical system, + +we have to beat on them +until they behave properly. + +So let's imagine that we have +a situation, such as this, + +where we have three parameters. + +Two of them are irrelevant. + +One of them is relevant. + +Then presumably, I +take my physical system + +at some temperature +and it would correspond + +to being on some point +in this phase diagram. + +Some color that we don't have. + +Let's say over here. + +And I change the temperature. + +And I will take +some trajectory-- + +in this case, three +dimensional space. + +And this is a line in this +three dimensional space. + +And experimentally, I've +been told that if I take, + +let's say, my piece of iron +and I change temperature, + +at some point I go +through a point that + +has infinite correlations. + +So I have to conclude that +my trajectory for iron + +will intersect with +surface at some point. + +And I'll say, OK, I take nickel. + +Nickel would be something else. + +And I change +temperature of nickel, + +and I will be doing something +completely different. + +But that experimentalist +also has a point + +where you have +ferromagnetic transition, + +so it must hit this surface. + +Then you do cobalt, where +some other trajectory + +comes and hits off the surface. + +Now what we now +know is that when + +we rescale the system +sufficiently, all of them + +ultimately are described +at the point where + +they have infinite +correlation length by what + +is going on over here. + +So if I take iron, +nickel, cobalt, clearly + +at the level of +atoms and molecules, + +they are very different +from each other. + +And the difference between +ironness, nickelness, + +cobaltness is really in all of +these irrelevant parameters. + +And as I go and look at +larger and larger scale, + +they all diminish and go away. + +And at large scale, +I see the same thing, + +where all of the individual +details has been washed out. + +So this is able to capture +the idea of universality. + +But there is a very +important caveat + +to this, which is that +the experimental system, + +whether you take iron or +cobalt or some mixture + +of these different elements, +you change one parameter + +temperature, and you always see +a transition from, let's say, + +paramagnetic to +ferromagnetic behavior. + +Now if I have, say, a line +here in three dimensional space + +and I draw another +line that corresponds + +to change in temperature, +I will not intersect it. + +I have to do something very +special to intersect that line. + +So in order that genetically I +have a phase transition-- which + +is what my experimentalist +friends tell me-- + +I know that I can only have +one relevant direction, + +because the dimensionality +of the basing of attraction + +is the dimensionality of +the space minus however + +many relevant directions I have. + +And I've been told +by experimentalists + +that they exchange +one parameters, + +and generically they +hit the surface. + +So that's part of the story. + +I better find a theory that, +at the end of the day, when + +I do all of this, I +find a fixed point that + +not only is well-behaved +and is not a limit cycle, + +but also a fixed point +that has one and only one + +relevant direction, if +that's the physical system + +that I'm describing. + +Now of course, maybe that +was for the superfluid, where + +they could only +change temperature, + +and you have a situation where +the magnet comes into play + +and they say, oh, actually we +also have the magnetic field. + +And we really have to go +to the space of zero field. + +And then if I expand +my space of parameters + +here to include terms +that break the symmetry, + +in that generalized +space, I should only + +have two relevant directions. + +So it is kind of strange story, +that all we are doing here + +is mathematics. + +But at the end of +the day, we have + +to get the mathematics to have +very specific properties that + +are dictated by very rough +things about experiments. + +So this was kind of +conceptually rich. + +So I'll let you digest +that for a while. + +And next lecture, we will start +actually doing this procedure + +and finding these kinds +of [INAUDIBLE] relations. \ No newline at end of file diff --git a/fW9ZyXvdCwE.txt b/fW9ZyXvdCwE.txt new file mode 100644 index 0000000000000000000000000000000000000000..9e5001342e44c28066a65bb828969955e6b94418 --- /dev/null +++ b/fW9ZyXvdCwE.txt @@ -0,0 +1,1747 @@ +align:start position:0% + +welcome back to ag20 special relativity + + align:start position:0% +welcome back to ag20 special relativity + + + align:start position:0% +welcome back to ag20 special relativity +in this short video we look at the + + align:start position:0% +in this short video we look at the + + + align:start position:0% +in this short video we look at the +historic backdrop the time in which + + align:start position:0% +historic backdrop the time in which + + + align:start position:0% +historic backdrop the time in which +Einstein was able to develop the theory + + align:start position:0% +Einstein was able to develop the theory + + + align:start position:0% +Einstein was able to develop the theory +of special relativity what were people + + align:start position:0% +of special relativity what were people + + + align:start position:0% +of special relativity what were people +thinking what was you know the physics + + align:start position:0% +thinking what was you know the physics + + + align:start position:0% +thinking what was you know the physics +landscape of the time + + align:start position:0% +landscape of the time + + + align:start position:0% +landscape of the time +how was technology developed and and how + + align:start position:0% +how was technology developed and and how + + + align:start position:0% +how was technology developed and and how +did all those things come together for + + align:start position:0% +did all those things come together for + + + align:start position:0% +did all those things come together for +Ein to thrive and come forward with + + align:start position:0% +Ein to thrive and come forward with + + + align:start position:0% +Ein to thrive and come forward with +those important discoveries in + + align:start position:0% +those important discoveries in + + + align:start position:0% +those important discoveries in +physics we have to go back to 1900 + + align:start position:0% +physics we have to go back to 1900 + + + align:start position:0% +physics we have to go back to 1900 +around that time in which Einstein was + + align:start position:0% +around that time in which Einstein was + + + align:start position:0% +around that time in which Einstein was +able to you + + align:start position:0% +able to you + + + align:start position:0% +able to you +know break through break out um and come + + align:start position:0% +know break through break out um and come + + + align:start position:0% +know break through break out um and come +up with completely new ideas and and pH + + align:start position:0% +up with completely new ideas and and pH + + + align:start position:0% +up with completely new ideas and and pH +um before we go into the discussion of + + align:start position:0% +um before we go into the discussion of + + + align:start position:0% +um before we go into the discussion of +of the + + align:start position:0% +of the + + + align:start position:0% +of the +timelines um I'd like you to be invited + + align:start position:0% +timelines um I'd like you to be invited + + + align:start position:0% +timelines um I'd like you to be invited +to come to Geneva to Switzerland to burn + + align:start position:0% +to come to Geneva to Switzerland to burn + + + align:start position:0% +to come to Geneva to Switzerland to burn +to Zurich to the places in which this + + align:start position:0% +to Zurich to the places in which this + + + align:start position:0% +to Zurich to the places in which this +all happened um especially burn is a is + + align:start position:0% +all happened um especially burn is a is + + + align:start position:0% +all happened um especially burn is a is +a historic town wasn't destroyed in the + + align:start position:0% +a historic town wasn't destroyed in the + + + align:start position:0% +a historic town wasn't destroyed in the +second world war and if you walk down + + align:start position:0% +second world war and if you walk down + + + align:start position:0% +second world war and if you walk down +the streets um here is a picture of me + + align:start position:0% +the streets um here is a picture of me + + + align:start position:0% +the streets um here is a picture of me +two years ago in front of the Einstein + + align:start position:0% +two years ago in front of the Einstein + + + align:start position:0% +two years ago in front of the Einstein +house you know the streets are basically + + align:start position:0% +house you know the streets are basically + + + align:start position:0% +house you know the streets are basically +unchanged for the last 100 150 years so + + align:start position:0% +unchanged for the last 100 150 years so + + + align:start position:0% +unchanged for the last 100 150 years so +you look up into the window and you see + + align:start position:0% +you look up into the window and you see + + + align:start position:0% +you look up into the window and you see +Einstein looking down at + + align:start position:0% +Einstein looking down at + + + align:start position:0% +Einstein looking down at +you um so if you go back 200 years um in + + align:start position:0% +you um so if you go back 200 years um in + + + align:start position:0% +you um so if you go back 200 years um in +Italy people like VTA and others started + + align:start position:0% +Italy people like VTA and others started + + + align:start position:0% +Italy people like VTA and others started +to make use of electromagnetic effects + + align:start position:0% +to make use of electromagnetic effects + + + align:start position:0% +to make use of electromagnetic effects +the first batteries were developed and a + + align:start position:0% +the first batteries were developed and a + + + align:start position:0% +the first batteries were developed and a +theory of wave a wave theory of light + + align:start position:0% +theory of wave a wave theory of light + + + align:start position:0% +theory of wave a wave theory of light +was developed that then LED you know in + + align:start position:0% +was developed that then LED you know in + + + align:start position:0% +was developed that then LED you know in +the you know slowly developed into a Ser + + align:start position:0% +the you know slowly developed into a Ser + + + align:start position:0% +the you know slowly developed into a Ser +of electromagnetism and the + + align:start position:0% +of electromagnetism and the + + + align:start position:0% +of electromagnetism and the +understanding of those phenomena in the + + align:start position:0% +understanding of those phenomena in the + + + align:start position:0% +understanding of those phenomena in the +very same time in Europe the first + + align:start position:0% +very same time in Europe the first + + + align:start position:0% +very same time in Europe the first +railroad systems were developed um + + align:start position:0% +railroad systems were developed um + + + align:start position:0% +railroad systems were developed um +electromagnetic induction was understood + + align:start position:0% +electromagnetic induction was understood + + + align:start position:0% +electromagnetic induction was understood +and then in 1860s in the 1860s Maxwell + + align:start position:0% +and then in 1860s in the 1860s Maxwell + + + align:start position:0% +and then in 1860s in the 1860s Maxwell +was able to put all of those Concepts + + align:start position:0% +was able to put all of those Concepts + + + align:start position:0% +was able to put all of those Concepts +together in his famous Maxville + + align:start position:0% +together in his famous Maxville + + + align:start position:0% +together in his famous Maxville +equations which are discuss discussed at + + align:start position:0% +equations which are discuss discussed at + + + align:start position:0% +equations which are discuss discussed at +length in + + align:start position:0% +length in + + + align:start position:0% +length in +802 people were then because of the + + align:start position:0% +802 people were then because of the + + + align:start position:0% +802 people were then because of the +railroads um but also because of graphic + + align:start position:0% +railroads um but also because of graphic + + + align:start position:0% +railroads um but also because of graphic +cables able to communicate and move over + + align:start position:0% +cables able to communicate and move over + + + align:start position:0% +cables able to communicate and move over +larger distance in shorter amount of + + align:start position:0% +larger distance in shorter amount of + + + align:start position:0% +larger distance in shorter amount of +time and that led to the need of + + align:start position:0% +time and that led to the need of + + + align:start position:0% +time and that led to the need of +synchronizing clocks uh to that point in + + align:start position:0% +synchronizing clocks uh to that point in + + + align:start position:0% +synchronizing clocks uh to that point in +each Town had one or few clock towers + + align:start position:0% +each Town had one or few clock towers + + + align:start position:0% +each Town had one or few clock towers +and you just read off the time and + + align:start position:0% +and you just read off the time and + + + align:start position:0% +and you just read off the time and +that's the time of day there was no need + + align:start position:0% +that's the time of day there was no need + + + align:start position:0% +that's the time of day there was no need +to be able to tell what time is it in + + align:start position:0% +to be able to tell what time is it in + + + align:start position:0% +to be able to tell what time is it in +London when you have your breakfast in + + align:start position:0% +London when you have your breakfast in + + + align:start position:0% +London when you have your breakfast in +Munich or uh what time you know the + + align:start position:0% +Munich or uh what time you know the + + + align:start position:0% +Munich or uh what time you know the +store opens in a different city there + + align:start position:0% +store opens in a different city there + + + align:start position:0% +store opens in a different city there +was no need for this kind of + + align:start position:0% +was no need for this kind of + + + align:start position:0% +was no need for this kind of +synchronization but with the expansion + + align:start position:0% +synchronization but with the expansion + + + align:start position:0% +synchronization but with the expansion +of railroad specifically there was a + + align:start position:0% +of railroad specifically there was a + + + align:start position:0% +of railroad specifically there was a +need to understand when a train when a + + align:start position:0% +need to understand when a train when a + + + align:start position:0% +need to understand when a train when a +when a uh train is on a track and such + + align:start position:0% +when a uh train is on a track and such + + + align:start position:0% +when a uh train is on a track and such +that it doesn't intersect with another + + align:start position:0% +that it doesn't intersect with another + + + align:start position:0% +that it doesn't intersect with another +train and you know avoiding collisions + + align:start position:0% +train and you know avoiding collisions + + + align:start position:0% +train and you know avoiding collisions +you also want to know when you have to + + align:start position:0% +you also want to know when you have to + + + align:start position:0% +you also want to know when you have to +be at a train station in order to catch + + align:start position:0% +be at a train station in order to catch + + + align:start position:0% +be at a train station in order to catch +the train uh those things became + + align:start position:0% +the train uh those things became + + + align:start position:0% +the train uh those things became +important and they led to patents filed + + align:start position:0% +important and they led to patents filed + + + align:start position:0% +important and they led to patents filed +around the this time and also later on + + align:start position:0% +around the this time and also later on + + + align:start position:0% +around the this time and also later on +on the theory of light people developed + + align:start position:0% +on the theory of light people developed + + + align:start position:0% +on the theory of light people developed +all kinds of ideas and conflicting ideas + + align:start position:0% +all kinds of ideas and conflicting ideas + + + align:start position:0% +all kinds of ideas and conflicting ideas +for example mechanical models of Light + + align:start position:0% +for example mechanical models of Light + + + align:start position:0% +for example mechanical models of Light +which relied on the existence of the + + align:start position:0% +which relied on the existence of the + + + align:start position:0% +which relied on the existence of the +medium in which light travels and we'll + + align:start position:0% +medium in which light travels and we'll + + + align:start position:0% +medium in which light travels and we'll +discuss this at length in the + + align:start position:0% +discuss this at length in the + + + align:start position:0% +discuss this at length in the +1818 um there's a new phenomena in the + + align:start position:0% +1818 um there's a new phenomena in the + + + align:start position:0% +1818 um there's a new phenomena in the +structure of physics after this point + + align:start position:0% +structure of physics after this point + + + align:start position:0% +structure of physics after this point +there was a professor of physics at an + + align:start position:0% +there was a professor of physics at an + + + align:start position:0% +there was a professor of physics at an +Institute he had a share and everybody + + align:start position:0% +Institute he had a share and everybody + + + align:start position:0% +Institute he had a share and everybody +was working for them um but then you + + align:start position:0% +was working for them um but then you + + + align:start position:0% +was working for them um but then you +know there was a a change in in in the + + align:start position:0% +know there was a a change in in in the + + + align:start position:0% +know there was a a change in in in the +way physics research was conducted such + + align:start position:0% +way physics research was conducted such + + + align:start position:0% +way physics research was conducted such +that started to be a division of labor + + align:start position:0% +that started to be a division of labor + + + align:start position:0% +that started to be a division of labor +between experimental physicist and + + align:start position:0% +between experimental physicist and + + + align:start position:0% +between experimental physicist and +theoretical + + align:start position:0% +theoretical + + + align:start position:0% +theoretical +physicist around this time Thomas Edison + + align:start position:0% +physicist around this time Thomas Edison + + + align:start position:0% +physicist around this time Thomas Edison +uh developed light bulbs uh meaning that + + align:start position:0% +uh developed light bulbs uh meaning that + + + align:start position:0% +uh developed light bulbs uh meaning that +light and electricity those two things + + align:start position:0% +light and electricity those two things + + + align:start position:0% +light and electricity those two things +became more woven together um + + align:start position:0% +became more woven together um + + + align:start position:0% +became more woven together um +electromagnetic waves were discovered + + align:start position:0% +electromagnetic waves were discovered + + + align:start position:0% +electromagnetic waves were discovered +and Michaelson and moley conducted the + + align:start position:0% +and Michaelson and moley conducted the + + + align:start position:0% +and Michaelson and moley conducted the +experiment and they did find they did + + align:start position:0% +experiment and they did find they did + + + align:start position:0% +experiment and they did find they did +not find a medium which carried light + + align:start position:0% +not find a medium which carried light + + + align:start position:0% +not find a medium which carried light +waves and we'll discuss the Michaels and + + align:start position:0% +waves and we'll discuss the Michaels and + + + align:start position:0% +waves and we'll discuss the Michaels and +mole experiment in much more depth um + + align:start position:0% +mole experiment in much more depth um + + + align:start position:0% +mole experiment in much more depth um +but this was basically the backdrop you + + align:start position:0% +but this was basically the backdrop you + + + align:start position:0% +but this was basically the backdrop you +know Michaelson and moley uh the idea of + + align:start position:0% +know Michaelson and moley uh the idea of + + + align:start position:0% +know Michaelson and moley uh the idea of +electromagnetic waves how do they + + align:start position:0% +electromagnetic waves how do they + + + align:start position:0% +electromagnetic waves how do they +actually travel uh what is the speed in + + align:start position:0% +actually travel uh what is the speed in + + + align:start position:0% +actually travel uh what is the speed in +which they travel what are the medium + + align:start position:0% +which they travel what are the medium + + + align:start position:0% +which they travel what are the medium +and how does this all interact + + align:start position:0% + + + + align:start position:0% + +so Einstein was born into this he was + + align:start position:0% +so Einstein was born into this he was + + + align:start position:0% +so Einstein was born into this he was +born in ol a German Town a small German + + align:start position:0% +born in ol a German Town a small German + + + align:start position:0% +born in ol a German Town a small German +Town on March 14th + + align:start position:0% +Town on March 14th + + + align:start position:0% +Town on March 14th +1879 on P day um he spent his youth in + + align:start position:0% +1879 on P day um he spent his youth in + + + align:start position:0% +1879 on P day um he spent his youth in +Munich where his father he was um he had + + align:start position:0% +Munich where his father he was um he had + + + align:start position:0% +Munich where his father he was um he had +an electrical company a company which uh + + align:start position:0% +an electrical company a company which uh + + + align:start position:0% +an electrical company a company which uh +provided electrical services for example + + align:start position:0% +provided electrical services for example + + + align:start position:0% +provided electrical services for example +for the octob October Fest in Munich um + + align:start position:0% +for the octob October Fest in Munich um + + + align:start position:0% +for the octob October Fest in Munich um +and his business went up and down and + + align:start position:0% +and his business went up and down and + + + align:start position:0% +and his business went up and down and +had to be located later into Italy um + + align:start position:0% +had to be located later into Italy um + + + align:start position:0% +had to be located later into Italy um +was difficult and interesting time so + + align:start position:0% +was difficult and interesting time so + + + align:start position:0% +was difficult and interesting time so +Einstein went to school in Munich in a + + align:start position:0% +Einstein went to school in Munich in a + + + align:start position:0% +Einstein went to school in Munich in a +gymnasium in in Munich uh and at some + + align:start position:0% +gymnasium in in Munich uh and at some + + + align:start position:0% +gymnasium in in Munich uh and at some +point it was time for him to go to + + align:start position:0% +point it was time for him to go to + + + align:start position:0% +point it was time for him to go to +military service and he avoided this by + + align:start position:0% +military service and he avoided this by + + + align:start position:0% +military service and he avoided this by +becoming stateless uh he then wanted to + + align:start position:0% +becoming stateless uh he then wanted to + + + align:start position:0% +becoming stateless uh he then wanted to +enroll in uh in University uh in + + align:start position:0% +enroll in uh in University uh in + + + align:start position:0% +enroll in uh in University uh in +Switzerland poly + + align:start position:0% +Switzerland poly + + + align:start position:0% +Switzerland poly +technique in um but he wasn't quite + + align:start position:0% +technique in um but he wasn't quite + + + align:start position:0% +technique in um but he wasn't quite +admitted uh + + align:start position:0% +admitted uh + + + align:start position:0% +admitted uh +mainly because his French wasn't quite + + align:start position:0% +mainly because his French wasn't quite + + + align:start position:0% +mainly because his French wasn't quite +sufficient so he had to go an extra + + align:start position:0% +sufficient so he had to go an extra + + + align:start position:0% +sufficient so he had to go an extra +round of studying in order to be then + + align:start position:0% +round of studying in order to be then + + + align:start position:0% +round of studying in order to be then +admitted to as a poly Technic one of his + + align:start position:0% +admitted to as a poly Technic one of his + + + align:start position:0% +admitted to as a poly Technic one of his +mentors at the time was hair Professor + + align:start position:0% +mentors at the time was hair Professor + + + align:start position:0% +mentors at the time was hair Professor +vber uh he was a leading physicist there + + align:start position:0% +vber uh he was a leading physicist there + + + align:start position:0% +vber uh he was a leading physicist there +and they had an interesting relationship + + align:start position:0% +and they had an interesting relationship + + + align:start position:0% +and they had an interesting relationship +which I come back to in a little while + + align:start position:0% +which I come back to in a little while + + + align:start position:0% +which I come back to in a little while +while studying in um in uh in in + + align:start position:0% +while studying in um in uh in in + + + align:start position:0% +while studying in um in uh in in +in in Zurich + + align:start position:0% +in in Zurich + + + align:start position:0% +in in Zurich +um Einstein met his wife miva + + align:start position:0% +um Einstein met his wife miva + + + align:start position:0% +um Einstein met his wife miva +marage um she was also a physics student + + align:start position:0% +marage um she was also a physics student + + + align:start position:0% +marage um she was also a physics student +one of the few female physics students + + align:start position:0% +one of the few female physics students + + + align:start position:0% +one of the few female physics students +there and they fell in love and they uh + + align:start position:0% +there and they fell in love and they uh + + + align:start position:0% +there and they fell in love and they uh +married and they had had a child + + align:start position:0% +married and they had had a child + + + align:start position:0% +married and they had had a child +together or children together in 1900 um + + align:start position:0% +together or children together in 1900 um + + + align:start position:0% +together or children together in 1900 um +Einstein graduated um he wasn't the best + + align:start position:0% +Einstein graduated um he wasn't the best + + + align:start position:0% +Einstein graduated um he wasn't the best +student in class um neither was miva + + align:start position:0% +student in class um neither was miva + + + align:start position:0% +student in class um neither was miva +marriage and he had a hard time finding + + align:start position:0% +marriage and he had a hard time finding + + + align:start position:0% +marriage and he had a hard time finding +a career so he wanted to stay at the UN + + align:start position:0% +a career so he wanted to stay at the UN + + + align:start position:0% +a career so he wanted to stay at the UN +University and enter an academic career + + align:start position:0% +University and enter an academic career + + + align:start position:0% +University and enter an academic career +and that required the mentors to be uh + + align:start position:0% +and that required the mentors to be uh + + + align:start position:0% +and that required the mentors to be uh +in favor of this and since Einstein + + align:start position:0% +in favor of this and since Einstein + + + align:start position:0% +in favor of this and since Einstein +didn't quite develop a good relationship + + align:start position:0% +didn't quite develop a good relationship + + + align:start position:0% +didn't quite develop a good relationship +with professor wber and the other um + + align:start position:0% +with professor wber and the other um + + + align:start position:0% +with professor wber and the other um +professors around uh they didn't want + + align:start position:0% +professors around uh they didn't want + + + align:start position:0% +professors around uh they didn't want +him there they didn't promote his career + + align:start position:0% +him there they didn't promote his career + + + align:start position:0% +him there they didn't promote his career +so he didn't know quite what to do um + + align:start position:0% +so he didn't know quite what to do um + + + align:start position:0% +so he didn't know quite what to do um +went back to his parents to Italy and + + align:start position:0% +went back to his parents to Italy and + + + align:start position:0% +went back to his parents to Italy and +and + + align:start position:0% +and + + + align:start position:0% +and +and this didn't get any traction from + + align:start position:0% +and this didn't get any traction from + + + align:start position:0% +and this didn't get any traction from +where he was and he was quite anxious + + align:start position:0% +where he was and he was quite anxious + + + align:start position:0% +where he was and he was quite anxious +about this and it just visible in + + align:start position:0% +about this and it just visible in + + + align:start position:0% +about this and it just visible in +letters he but he had good friends there + + align:start position:0% +letters he but he had good friends there + + + align:start position:0% +letters he but he had good friends there +um he had a good friend Marcel Crossman + + align:start position:0% +um he had a good friend Marcel Crossman + + + align:start position:0% +um he had a good friend Marcel Crossman +specifically who helped him get into + + align:start position:0% +specifically who helped him get into + + + align:start position:0% +specifically who helped him get into +after some back and forth a position as + + align:start position:0% +after some back and forth a position as + + + align:start position:0% +after some back and forth a position as +a lower level patent clerk um in a patn + + align:start position:0% +a lower level patent clerk um in a patn + + + align:start position:0% +a lower level patent clerk um in a patn +office in burn and so this was a + + align:start position:0% +office in burn and so this was a + + + align:start position:0% +office in burn and so this was a +starting point for career so he had this + + align:start position:0% +starting point for career so he had this + + + align:start position:0% +starting point for career so he had this +you know was a pattern clerk he had a + + align:start position:0% +you know was a pattern clerk he had a + + + align:start position:0% +you know was a pattern clerk he had a +lot of time on his hand Beyond say and + + align:start position:0% +lot of time on his hand Beyond say and + + + align:start position:0% +lot of time on his hand Beyond say and +they started something which was called + + align:start position:0% +they started something which was called + + + align:start position:0% +they started something which was called +the um um Olympia Academy which uh you + + align:start position:0% +the um um Olympia Academy which uh you + + + align:start position:0% +the um um Olympia Academy which uh you +know consisted of a group of people who + + align:start position:0% +know consisted of a group of people who + + + align:start position:0% +know consisted of a group of people who +studied with and Friends of Einstein + + align:start position:0% +studied with and Friends of Einstein + + + align:start position:0% +studied with and Friends of Einstein +including um Marcel Crosman and they + + align:start position:0% +including um Marcel Crosman and they + + + align:start position:0% +including um Marcel Crosman and they +talked and spent time took long walks uh + + align:start position:0% +talked and spent time took long walks uh + + + align:start position:0% +talked and spent time took long walks uh +you know spend time drinking partying if + + align:start position:0% +you know spend time drinking partying if + + + align:start position:0% +you know spend time drinking partying if +you want um and but specifically talking + + align:start position:0% +you want um and but specifically talking + + + align:start position:0% +you want um and but specifically talking +about physics um and in this framework + + align:start position:0% +about physics um and in this framework + + + align:start position:0% +about physics um and in this framework +Einstein was able to develop his + + align:start position:0% +Einstein was able to develop his + + + align:start position:0% +Einstein was able to develop his +ideas and then 1905 came uh not in a + + align:start position:0% +ideas and then 1905 came uh not in a + + + align:start position:0% +ideas and then 1905 came uh not in a +sudden but in 1905 he was able out of + + align:start position:0% +sudden but in 1905 he was able out of + + + align:start position:0% +sudden but in 1905 he was able out of +this context to develop develop five + + align:start position:0% +this context to develop develop five + + + align:start position:0% +this context to develop develop five +very very important paper the first one + + align:start position:0% +very very important paper the first one + + + align:start position:0% +very very important paper the first one +was on light Quantum um he was able to + + align:start position:0% +was on light Quantum um he was able to + + + align:start position:0% +was on light Quantum um he was able to +describe the emission and absorption of + + align:start position:0% +describe the emission and absorption of + + + align:start position:0% +describe the emission and absorption of +light in April then which was part of + + align:start position:0% +light in April then which was part of + + + align:start position:0% +light in April then which was part of +his PhD seases he was able to uh + + align:start position:0% +his PhD seases he was able to uh + + + align:start position:0% +his PhD seases he was able to uh +characterize the size of molecules and + + align:start position:0% +characterize the size of molecules and + + + align:start position:0% +characterize the size of molecules and +in may he was able to show the existence + + align:start position:0% +in may he was able to show the existence + + + align:start position:0% +in may he was able to show the existence +of atoms he was basically demonstrating + + align:start position:0% +of atoms he was basically demonstrating + + + align:start position:0% +of atoms he was basically demonstrating +this by following Browning random motion + + align:start position:0% +this by following Browning random motion + + + align:start position:0% +this by following Browning random motion +of + + align:start position:0% +of + + + align:start position:0% +of +atoms and then in June he wrote a paper + + align:start position:0% +atoms and then in June he wrote a paper + + + align:start position:0% +atoms and then in June he wrote a paper +named electrodynamics of moving bodies + + align:start position:0% +named electrodynamics of moving bodies + + + align:start position:0% +named electrodynamics of moving bodies +and that is the paper in which he + + align:start position:0% +and that is the paper in which he + + + align:start position:0% +and that is the paper in which he +discovers or describes special + + align:start position:0% +discovers or describes special + + + align:start position:0% +discovers or describes special +relativity on further review he + + align:start position:0% +relativity on further review he + + + align:start position:0% +relativity on further review he +discovered that there's a consequent of + + align:start position:0% +discovered that there's a consequent of + + + align:start position:0% +discovered that there's a consequent of +special relative ity that energy and + + align:start position:0% +special relative ity that energy and + + + align:start position:0% +special relative ity that energy and +mass are equivalent in this famous + + align:start position:0% +mass are equivalent in this famous + + + align:start position:0% +mass are equivalent in this famous +equation eal mc² and we'll come to this + + align:start position:0% +equation eal mc² and we'll come to this + + + align:start position:0% +equation eal mc² and we'll come to this +as well so this is basically the + + align:start position:0% +as well so this is basically the + + + align:start position:0% +as well so this is basically the +framework of of this lecture um if you + + align:start position:0% +framework of of this lecture um if you + + + align:start position:0% +framework of of this lecture um if you +then move forward into general + + align:start position:0% +then move forward into general + + + align:start position:0% +then move forward into general +relativity which was developed by + + align:start position:0% +relativity which was developed by + + + align:start position:0% +relativity which was developed by +Einstein in + + align:start position:0% +Einstein in + + + align:start position:0% +Einstein in +1915 um you can then again follow the + + align:start position:0% +1915 um you can then again follow the + + + align:start position:0% +1915 um you can then again follow the +developments of Science of quantum + + align:start position:0% +developments of Science of quantum + + + align:start position:0% +developments of Science of quantum +mechanics of general relativity and the + + align:start position:0% +mechanics of general relativity and the + + + align:start position:0% +mechanics of general relativity and the +conundrum of describing those two + + align:start position:0% +conundrum of describing those two + + + align:start position:0% +conundrum of describing those two +concepts at the very same time in which + + align:start position:0% +concepts at the very same time in which + + + align:start position:0% +concepts at the very same time in which +then Einstein lived and moved his career + + align:start position:0% +then Einstein lived and moved his career + + + align:start position:0% +then Einstein lived and moved his career +developed then from there + + align:start position:0% +developed then from there + + + align:start position:0% +developed then from there +on not instantly but systematically he + + align:start position:0% +on not instantly but systematically he + + + align:start position:0% +on not instantly but systematically he +had a call as a professor in uh in + + align:start position:0% +had a call as a professor in uh in + + + align:start position:0% +had a call as a professor in uh in +Berlin later on and uh after the Nazis + + align:start position:0% +Berlin later on and uh after the Nazis + + + align:start position:0% +Berlin later on and uh after the Nazis +took over in Germany decided to free + + align:start position:0% +took over in Germany decided to free + + + align:start position:0% +took over in Germany decided to free +Germany and he went moved to the United + + align:start position:0% +Germany and he went moved to the United + + + align:start position:0% +Germany and he went moved to the United +States where he took on a position in + + align:start position:0% +States where he took on a position in + + + align:start position:0% +States where he took on a position in +Princeton um the rest is history as you + + align:start position:0% +Princeton um the rest is history as you + + + align:start position:0% +Princeton um the rest is history as you +want and we'll hear more about this uh + + align:start position:0% +want and we'll hear more about this uh + + + align:start position:0% +want and we'll hear more about this uh +tomorrow \ No newline at end of file diff --git a/fXlzY2l1-4w.txt b/fXlzY2l1-4w.txt new file mode 100644 index 0000000000000000000000000000000000000000..ed2dd1dacffb67990c08f2b5c5ef2730689ca1ae --- /dev/null +++ b/fXlzY2l1-4w.txt @@ -0,0 +1,2531 @@ +align:start position:0% + +we spoke about the hydrogen atom and in + + align:start position:0% +we spoke about the hydrogen atom and in + + + align:start position:0% +we spoke about the hydrogen atom and in +the hydrogen atom we drew the spectrum + + align:start position:0% +the hydrogen atom we drew the spectrum + + + align:start position:0% +the hydrogen atom we drew the spectrum +so the table the data of spectrum of a + + align:start position:0% +so the table the data of spectrum of a + + + align:start position:0% +so the table the data of spectrum of a +quantum system so this is a question + + align:start position:0% +quantum system so this is a question + + + align:start position:0% +quantum system so this is a question +that they want you in general to be + + align:start position:0% +that they want you in general to be + + + align:start position:0% +that they want you in general to be +aware of what do we mean by a diagram of + + align:start position:0% +aware of what do we mean by a diagram of + + + align:start position:0% +aware of what do we mean by a diagram of +the energy levels in a central potential + + align:start position:0% +the energy levels in a central potential + + + align:start position:0% +the energy levels in a central potential +so this is something we did for the + + align:start position:0% +so this is something we did for the + + + align:start position:0% +so this is something we did for the +hydrogen atom but in general the diagram + + align:start position:0% +hydrogen atom but in general the diagram + + + align:start position:0% +hydrogen atom but in general the diagram +of energy eigenstates in a central + + align:start position:0% +of energy eigenstates in a central + + + align:start position:0% +of energy eigenstates in a central +potential looks like this you put the + + align:start position:0% +potential looks like this you put the + + + align:start position:0% +potential looks like this you put the +energies here and they could be bound + + align:start position:0% +energies here and they could be bound + + + align:start position:0% +energies here and they could be bound +states that have negative energy they + + align:start position:0% +states that have negative energy they + + + align:start position:0% +states that have negative energy they +could be even bound States with positive + + align:start position:0% +could be even bound States with positive + + + align:start position:0% +could be even bound States with positive +energy depending on the system you are + + align:start position:0% +energy depending on the system you are + + + align:start position:0% +energy depending on the system you are +discussing like you remember the + + align:start position:0% +discussing like you remember the + + + align:start position:0% +discussing like you remember the +harmonic oscillator the potential is + + align:start position:0% +harmonic oscillator the potential is + + + align:start position:0% +harmonic oscillator the potential is +naturally defined to be positive and all + + align:start position:0% +naturally defined to be positive and all + + + align:start position:0% +naturally defined to be positive and all +these energy states that harmonic + + align:start position:0% +these energy states that harmonic + + + align:start position:0% +these energy states that harmonic +oscillator has represent bound States + + align:start position:0% +oscillator has represent bound States + + + align:start position:0% +oscillator has represent bound States +there normalizable wave function in fact + + align:start position:0% +there normalizable wave function in fact + + + align:start position:0% +there normalizable wave function in fact +you don't have scattering States because + + align:start position:0% +you don't have scattering States because + + + align:start position:0% +you don't have scattering States because +the potential just reaches forever so in + + align:start position:0% +the potential just reaches forever so in + + + align:start position:0% +the potential just reaches forever so in +general for a central potential however + + align:start position:0% +general for a central potential however + + + align:start position:0% +general for a central potential however +of the the system is shown like that and + + align:start position:0% +of the the system is shown like that and + + + align:start position:0% +of the the system is shown like that and +we plot here L but L is not a continuous + + align:start position:0% +we plot here L but L is not a continuous + + + align:start position:0% +we plot here L but L is not a continuous +variable so we'll put like l equals 0 + + align:start position:0% +variable so we'll put like l equals 0 + + + align:start position:0% +variable so we'll put like l equals 0 +here l equals 1 l equals 2 l equals 3 + + align:start position:0% +here l equals 1 l equals 2 l equals 3 + + + align:start position:0% +here l equals 1 l equals 2 l equals 3 +and then you start plotting the energy + + align:start position:0% +and then you start plotting the energy + + + align:start position:0% +and then you start plotting the energy +levels you solve the radial equation + + align:start position:0% +levels you solve the radial equation + + + align:start position:0% +levels you solve the radial equation +remember the radial equation is a + + align:start position:0% +remember the radial equation is a + + + align:start position:0% +remember the radial equation is a +Schrodinger equation minus h squared + + align:start position:0% +Schrodinger equation minus h squared + + + align:start position:0% +Schrodinger equation minus h squared +over 2m these second you the R squared + + align:start position:0% +over 2m these second you the R squared + + + align:start position:0% +over 2m these second you the R squared +plus V effective of R u equals EU and V + + align:start position:0% +plus V effective of R u equals EU and V + + + align:start position:0% +plus V effective of R u equals EU and V +effective of R is the V of R that your + + align:start position:0% +effective of R is the V of R that your + + + align:start position:0% +effective of R is the V of R that your +system had plus a contribution for + + align:start position:0% +system had plus a contribution for + + + align:start position:0% +system had plus a contribution for +angular momentum to sew up this radial + + align:start position:0% +angular momentum to sew up this radial + + + align:start position:0% +angular momentum to sew up this radial +equation is a collection of radial + + align:start position:0% +equation is a collection of radial + + + align:start position:0% +equation is a collection of radial +equations with try to emphasize that + + align:start position:0% +equations with try to emphasize that + + + align:start position:0% +equations with try to emphasize that +many times already and you solve it + + align:start position:0% +many times already and you solve it + + + align:start position:0% +many times already and you solve it +first for l equals 0 and for a liquid + + align:start position:0% +first for l equals 0 and for a liquid + + + align:start position:0% +first for l equals 0 and for a liquid +one for L equal 2 you go on and on + + align:start position:0% +one for L equal 2 you go on and on + + + align:start position:0% +one for L equal 2 you go on and on +so you solve it for l equals 0 as an as + + align:start position:0% +so you solve it for l equals 0 as an as + + + align:start position:0% +so you solve it for l equals 0 as an as +and just like us in any one dimensional + + align:start position:0% +and just like us in any one dimensional + + + align:start position:0% +and just like us in any one dimensional +problem for l equals 0 you solve this + + align:start position:0% +problem for l equals 0 you solve this + + + align:start position:0% +problem for l equals 0 you solve this +equation and you find energy levels so + + align:start position:0% +equation and you find energy levels so + + + align:start position:0% +equation and you find energy levels so +you sketch them like that those are the + + align:start position:0% +you sketch them like that those are the + + + align:start position:0% +you sketch them like that those are the +energy levels for l equals 0 this is the + + align:start position:0% +energy levels for l equals 0 this is the + + + align:start position:0% +energy levels for l equals 0 this is the +ground state of the l equals 0 radial + + align:start position:0% +ground state of the l equals 0 radial + + + align:start position:0% +ground state of the l equals 0 radial +equation now just to remind you this is + + align:start position:0% +equation now just to remind you this is + + + align:start position:0% +equation now just to remind you this is +the hard part of solving the Schrodinger + + align:start position:0% +the hard part of solving the Schrodinger + + + align:start position:0% +the hard part of solving the Schrodinger +equation because at the end of the day + + align:start position:0% +equation because at the end of the day + + + align:start position:0% +equation because at the end of the day +the PSI is U of R over R times some ylm + + align:start position:0% + + + + align:start position:0% + +so the L that you have here determines + + align:start position:0% +so the L that you have here determines + + + align:start position:0% +so the L that you have here determines +the Y and the M is arbitrary in fact the + + align:start position:0% +the Y and the M is arbitrary in fact the + + + align:start position:0% +the Y and the M is arbitrary in fact the +you doesn't know about the M value so + + align:start position:0% +you doesn't know about the M value so + + + align:start position:0% +you doesn't know about the M value so +here you have this energy levels and + + align:start position:0% +here you have this energy levels and + + + align:start position:0% +here you have this energy levels and +then what happened with the with this + + align:start position:0% +then what happened with the with this + + + align:start position:0% +then what happened with the with this +hydrogen atom is you keep solving of + + align:start position:0% +hydrogen atom is you keep solving of + + + align:start position:0% +hydrogen atom is you keep solving of +course for all the else and in general + + align:start position:0% +course for all the else and in general + + + align:start position:0% +course for all the else and in general +when you solve for L equal 1 you may + + align:start position:0% +when you solve for L equal 1 you may + + + align:start position:0% +when you solve for L equal 1 you may +find some levels like this it's a + + align:start position:0% +find some levels like this it's a + + + align:start position:0% +find some levels like this it's a +miracle + + align:start position:0% +miracle + + + align:start position:0% +miracle +when the levels coincide there's no + + align:start position:0% +when the levels coincide there's no + + + align:start position:0% +when the levels coincide there's no +reason why they should coincide they + + align:start position:0% +reason why they should coincide they + + + align:start position:0% +reason why they should coincide they +happen to coincide for the hydrogen atom + + align:start position:0% +happen to coincide for the hydrogen atom + + + align:start position:0% +happen to coincide for the hydrogen atom +and that's because of a very special + + align:start position:0% +and that's because of a very special + + + align:start position:0% +and that's because of a very special +symmetry of the 1 over R potential orbit + + align:start position:0% +symmetry of the 1 over R potential orbit + + + align:start position:0% +symmetry of the 1 over R potential orbit +then for L equal to you solve it and for + + align:start position:0% +then for L equal to you solve it and for + + + align:start position:0% +then for L equal to you solve it and for +L equal 3 you solve and you find the + + align:start position:0% +L equal 3 you solve and you find the + + + align:start position:0% +L equal 3 you solve and you find the +station that's the diagram of states of + + align:start position:0% +station that's the diagram of states of + + + align:start position:0% +station that's the diagram of states of +a central potential for the hydrogen + + align:start position:0% +a central potential for the hydrogen + + + align:start position:0% +a central potential for the hydrogen +atom of course they first all the + + align:start position:0% +atom of course they first all the + + + align:start position:0% +atom of course they first all the +energies were negative and the energy + + align:start position:0% +energies were negative and the energy + + + align:start position:0% +energies were negative and the energy +levels coincide so + + align:start position:0% +levels coincide so + + + align:start position:0% +levels coincide so +this is the ground state of the l equals + + align:start position:0% +this is the ground state of the l equals + + + align:start position:0% +this is the ground state of the l equals +0 radio equation this is the ground + + align:start position:0% +0 radio equation this is the ground + + + align:start position:0% +0 radio equation this is the ground +state of the L equal 1 radial equation + + align:start position:0% +state of the L equal 1 radial equation + + + align:start position:0% +state of the L equal 1 radial equation +this is a grunt sense of the L equal to + + align:start position:0% +this is a grunt sense of the L equal to + + + align:start position:0% +this is a grunt sense of the L equal to +radial equation this is the ground state + + align:start position:0% +radial equation this is the ground state + + + align:start position:0% +radial equation this is the ground state +of the whole system so this is what we + + align:start position:0% +of the whole system so this is what we + + + align:start position:0% +of the whole system so this is what we +call plotting the spectrum in a in a + + align:start position:0% +call plotting the spectrum in a in a + + + align:start position:0% +call plotting the spectrum in a in a +radial potential problem and it's a + + align:start position:0% +radial potential problem and it's a + + + align:start position:0% +radial potential problem and it's a +generic form so we were doing this for + + align:start position:0% +generic form so we were doing this for + + + align:start position:0% +generic form so we were doing this for +the hydrogen atom last time to try to + + align:start position:0% +the hydrogen atom last time to try to + + + align:start position:0% +the hydrogen atom last time to try to +understand the various orbits and we had + + align:start position:0% + + + + align:start position:0% + +for the hydrogen atom V of R was a + + align:start position:0% +for the hydrogen atom V of R was a + + + align:start position:0% +for the hydrogen atom V of R was a +potential like this minus e squared over + + align:start position:0% +potential like this minus e squared over + + + align:start position:0% +potential like this minus e squared over +R and then you have sometimes the L + + align:start position:0% +R and then you have sometimes the L + + + align:start position:0% +R and then you have sometimes the L +contribution that this function diverges + + align:start position:0% +contribution that this function diverges + + + align:start position:0% +contribution that this function diverges +towards the origin 1 over R squared and + + align:start position:0% +towards the origin 1 over R squared and + + + align:start position:0% +towards the origin 1 over R squared and +by the time you add them together this + + align:start position:0% +by the time you add them together this + + + align:start position:0% +by the time you add them together this +is the original potential so this could + + align:start position:0% +is the original potential so this could + + + align:start position:0% +is the original potential so this could +be thought as L equals 0 case then when + + align:start position:0% +be thought as L equals 0 case then when + + + align:start position:0% +be thought as L equals 0 case then when +if you have L sub L over here and some + + align:start position:0% +if you have L sub L over here and some + + + align:start position:0% +if you have L sub L over here and some +other L maybe like that these are the + + align:start position:0% +other L maybe like that these are the + + + align:start position:0% +other L maybe like that these are the +various potentials that you get and in + + align:start position:0% +various potentials that you get and in + + + align:start position:0% +various potentials that you get and in +general you may want to figure out for + + align:start position:0% +general you may want to figure out for + + + align:start position:0% +general you may want to figure out for +example if you have an energy level some + + align:start position:0% +example if you have an energy level some + + + align:start position:0% +example if you have an energy level some +particular energy what are the turning + + align:start position:0% +particular energy what are the turning + + + align:start position:0% +particular energy what are the turning +point so let's consider for that case + + align:start position:0% +point so let's consider for that case + + + align:start position:0% +point so let's consider for that case +it's just one curve that we care about + + align:start position:0% + + + + align:start position:0% + +and the electron will be going from some + + align:start position:0% +and the electron will be going from some + + + align:start position:0% +and the electron will be going from some +value of the radius so this is the plot + + align:start position:0% +value of the radius so this is the plot + + + align:start position:0% +value of the radius so this is the plot +of the effective potential as a function + + align:start position:0% +of the effective potential as a function + + + align:start position:0% +of the effective potential as a function +of radius it will go from one to another + + align:start position:0% +of radius it will go from one to another + + + align:start position:0% +of radius it will go from one to another +they could be called R minus 2r plus and + + align:start position:0% +they could be called R minus 2r plus and + + + align:start position:0% +they could be called R minus 2r plus and +our semi classical interpretation which + + align:start position:0% +our semi classical interpretation which + + + align:start position:0% +our semi classical interpretation which +is roughly good if you're talking about + + align:start position:0% +is roughly good if you're talking about + + + align:start position:0% +is roughly good if you're talking about +high quantum + + align:start position:0% +high quantum + + + align:start position:0% +high quantum +numbers hi principal quantum numbers + + align:start position:0% +numbers hi principal quantum numbers + + + align:start position:0% +numbers hi principal quantum numbers +high l quantum numbers is that you have + + align:start position:0% +high l quantum numbers is that you have + + + align:start position:0% +high l quantum numbers is that you have +an ellipse on the radial distance to the + + align:start position:0% +an ellipse on the radial distance to the + + + align:start position:0% +an ellipse on the radial distance to the +center where the proton is located go + + align:start position:0% +center where the proton is located go + + + align:start position:0% +center where the proton is located go +from our plus to our minus the electron + + align:start position:0% +from our plus to our minus the electron + + + align:start position:0% +from our plus to our minus the electron +is bouncing back and forth that is the + + align:start position:0% +is bouncing back and forth that is the + + + align:start position:0% +is bouncing back and forth that is the +classical picture in the quantum + + align:start position:0% +classical picture in the quantum + + + align:start position:0% +classical picture in the quantum +mechanical picture you expect something + + align:start position:0% +mechanical picture you expect something + + + align:start position:0% +mechanical picture you expect something +somewhat similar there's going to be a + + align:start position:0% +somewhat similar there's going to be a + + + align:start position:0% +somewhat similar there's going to be a +wave function maybe a wave function here + + align:start position:0% +wave function maybe a wave function here + + + align:start position:0% +wave function maybe a wave function here +sy squared and it's it's going to be + + align:start position:0% +sy squared and it's it's going to be + + + align:start position:0% +sy squared and it's it's going to be +vanishing Li small before this point and + + align:start position:0% +vanishing Li small before this point and + + + align:start position:0% +vanishing Li small before this point and +then by the time you get here it's going + + align:start position:0% +then by the time you get here it's going + + + align:start position:0% +then by the time you get here it's going +to be very fast or and then decay again + + align:start position:0% +to be very fast or and then decay again + + + align:start position:0% +to be very fast or and then decay again +so the probability distribution will + + align:start position:0% +so the probability distribution will + + + align:start position:0% +so the probability distribution will +sort of mimic the time spent by the + + align:start position:0% +sort of mimic the time spent by the + + + align:start position:0% +sort of mimic the time spent by the +particles we used to argue before so + + align:start position:0% +particles we used to argue before so + + + align:start position:0% +particles we used to argue before so +let's do a little exercise of + + align:start position:0% +let's do a little exercise of + + + align:start position:0% +let's do a little exercise of +calculating the the turning points so + + align:start position:0% +calculating the the turning points so + + + align:start position:0% +calculating the the turning points so +how do we do that well we set H squared + + align:start position:0% +how do we do that well we set H squared + + + align:start position:0% +how do we do that well we set H squared +L times L plus 1 over 2m R squared minus + + align:start position:0% +L times L plus 1 over 2m R squared minus + + + align:start position:0% +L times L plus 1 over 2m R squared minus +e squared over R that's the effective + + align:start position:0% +e squared over R that's the effective + + + align:start position:0% +e squared over R that's the effective +potential equal to the energy of some + + align:start position:0% +potential equal to the energy of some + + + align:start position:0% +potential equal to the energy of some +level and principal quantum number n so + + align:start position:0% +level and principal quantum number n so + + + align:start position:0% +level and principal quantum number n so +it will be minus e squared over 2 a 0 1 + + align:start position:0% +it will be minus e squared over 2 a 0 1 + + + align:start position:0% +it will be minus e squared over 2 a 0 1 +over m squared that's the value of the + + align:start position:0% +over m squared that's the value of the + + + align:start position:0% +over m squared that's the value of the +energy M and the solutions of this + + align:start position:0% +energy M and the solutions of this + + + align:start position:0% +energy M and the solutions of this +quadratic equation are going to give us + + align:start position:0% +quadratic equation are going to give us + + + align:start position:0% +quadratic equation are going to give us +the R plus and the R minus of the orbit + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% + + + + align:start position:0% + +it's probably worthwhile to do a little + + align:start position:0% +it's probably worthwhile to do a little + + + align:start position:0% +it's probably worthwhile to do a little +transformation and to say are equal 0 + + align:start position:0% +transformation and to say are equal 0 + + + align:start position:0% +transformation and to say are equal 0 +times X where X is unit 3 and then the + + align:start position:0% +times X where X is unit 3 and then the + + + align:start position:0% +times X where X is unit 3 and then the +equation becomes H squared L times L + + align:start position:0% +equation becomes H squared L times L + + + align:start position:0% +equation becomes H squared L times L +plus 1 over 2m a squared is 0 squared + + align:start position:0% +plus 1 over 2m a squared is 0 squared + + + align:start position:0% +plus 1 over 2m a squared is 0 squared +times L times L plus 1 over x squared + + align:start position:0% + + + + align:start position:0% + +minus y squared over a not X is equal to + + align:start position:0% +minus y squared over a not X is equal to + + + align:start position:0% +minus y squared over a not X is equal to +minus e squared over 2a not 1 over m + + align:start position:0% +minus e squared over 2a not 1 over m + + + align:start position:0% +minus e squared over 2a not 1 over m +squared so we unit should work out we + + align:start position:0% +squared so we unit should work out we + + + align:start position:0% +squared so we unit should work out we +should get a nice equation without unit + + align:start position:0% +should get a nice equation without unit + + + align:start position:0% +should get a nice equation without unit +so what must be happening is that the + + align:start position:0% +so what must be happening is that the + + + align:start position:0% +so what must be happening is that the +coefficient in front of here H squared + + align:start position:0% +coefficient in front of here H squared + + + align:start position:0% +coefficient in front of here H squared +2m a 0 squared let's take the other a 0 + + align:start position:0% +2m a 0 squared let's take the other a 0 + + + align:start position:0% +2m a 0 squared let's take the other a 0 +and separate it out and transform this + + align:start position:0% +and separate it out and transform this + + + align:start position:0% +and separate it out and transform this +remember a 0 was H squared over m e + + align:start position:0% +remember a 0 was H squared over m e + + + align:start position:0% +remember a 0 was H squared over m e +squared so so here we get h squared over + + align:start position:0% +squared so so here we get h squared over + + + align:start position:0% +squared so so here we get h squared over +2m a 0 and that is 0 now has an H + + align:start position:0% +2m a 0 and that is 0 now has an H + + + align:start position:0% +2m a 0 and that is 0 now has an H +squared and there's M e squared so the + + align:start position:0% +squared and there's M e squared so the + + + align:start position:0% +squared and there's M e squared so the +h-word cancels the M cancels this is e + + align:start position:0% +h-word cancels the M cancels this is e + + + align:start position:0% +h-word cancels the M cancels this is e +squared over 2a 0 so this whole + + align:start position:0% +squared over 2a 0 so this whole + + + align:start position:0% +squared over 2a 0 so this whole +coefficient is e squared over 2a 0 which + + align:start position:0% +coefficient is e squared over 2a 0 which + + + align:start position:0% +coefficient is e squared over 2a 0 which +is nice because now the e squared over a + + align:start position:0% +is nice because now the e squared over a + + + align:start position:0% +is nice because now the e squared over a +0 the e squared over 2a squared over + + align:start position:0% +0 the e squared over 2a squared over + + + align:start position:0% +0 the e squared over 2a squared over +easy + + align:start position:0% +easy + + + align:start position:0% +easy +your counsel and we get a L times L plus + + align:start position:0% +your counsel and we get a L times L plus + + + align:start position:0% +your counsel and we get a L times L plus +one over x squared I've cancelled all + + align:start position:0% +one over x squared I've cancelled all + + + align:start position:0% +one over x squared I've cancelled all +this factor -2 over X is equal to minus + + align:start position:0% +this factor -2 over X is equal to minus + + + align:start position:0% +this factor -2 over X is equal to minus +1 over N squared so I multiplied by the + + align:start position:0% +1 over N squared so I multiplied by the + + + align:start position:0% +1 over N squared so I multiplied by the +inverse of this quantity it clears up + + align:start position:0% +inverse of this quantity it clears up + + + align:start position:0% +inverse of this quantity it clears up +the factor in the first term it produces + + align:start position:0% +the factor in the first term it produces + + + align:start position:0% +the factor in the first term it produces +an extra factor of 2 in the second term + + align:start position:0% +an extra factor of 2 in the second term + + + align:start position:0% +an extra factor of 2 in the second term +and you've got a nice simple quadratic + + align:start position:0% +and you've got a nice simple quadratic + + + align:start position:0% +and you've got a nice simple quadratic +equation yes um oh there's no no such + + align:start position:0% +equation yes um oh there's no no such + + + align:start position:0% +equation yes um oh there's no no such +thing there's too many of them thank you + + align:start position:0% +thing there's too many of them thank you + + + align:start position:0% +thing there's too many of them thank you +very much yes too many 1 over x squared + + align:start position:0% +very much yes too many 1 over x squared + + + align:start position:0% +very much yes too many 1 over x squared +thank you so let's move this to the + + align:start position:0% +thank you so let's move this to the + + + align:start position:0% +thank you so let's move this to the +other side plus 1 over N squared equals + + align:start position:0% +other side plus 1 over N squared equals + + + align:start position:0% +other side plus 1 over N squared equals +0 so you have this is the main equation + + align:start position:0% +0 so you have this is the main equation + + + align:start position:0% +0 so you have this is the main equation +and we can write this up well the + + align:start position:0% +and we can write this up well the + + + align:start position:0% +and we can write this up well the +solution for 1 over X is a quadratic + + align:start position:0% +solution for 1 over X is a quadratic + + + align:start position:0% +solution for 1 over X is a quadratic +equation in 1 over X so it's some I'll + + align:start position:0% +equation in 1 over X so it's some I'll + + + align:start position:0% +equation in 1 over X so it's some I'll +write it here 1 plus minus square root + + align:start position:0% +write it here 1 plus minus square root + + + align:start position:0% +write it here 1 plus minus square root +of 1 minus L times L plus 1 over N + + align:start position:0% +of 1 minus L times L plus 1 over N + + + align:start position:0% +of 1 minus L times L plus 1 over N +squared divided by L times L plus 1 + + align:start position:0% + + + + align:start position:0% + +that's just from the quadratic formula + + align:start position:0% +that's just from the quadratic formula + + + align:start position:0% +that's just from the quadratic formula +so then you invert it so X is now L + + align:start position:0% +so then you invert it so X is now L + + + align:start position:0% +so then you invert it so X is now L +times L plus 1 over 1 plus minus square + + align:start position:0% +times L plus 1 over 1 plus minus square + + + align:start position:0% +times L plus 1 over 1 plus minus square +root of 1 minus L L plus 1 over N + + align:start position:0% +root of 1 minus L L plus 1 over N + + + align:start position:0% +root of 1 minus L L plus 1 over N +squared and we multiplied by the + + align:start position:0% +squared and we multiplied by the + + + align:start position:0% +squared and we multiplied by the +opposite factor to clear the square root + + align:start position:0% +opposite factor to clear the square root + + + align:start position:0% +opposite factor to clear the square root +so 1 minus plus square root of 1 minus L + + align:start position:0% +so 1 minus plus square root of 1 minus L + + + align:start position:0% +so 1 minus plus square root of 1 minus L +times L plus 1 over N squared and the + + align:start position:0% +times L plus 1 over N squared and the + + + align:start position:0% +times L plus 1 over N squared and the +same factor here 1 minus plus square + + align:start position:0% +same factor here 1 minus plus square + + + align:start position:0% +same factor here 1 minus plus square +root of 1 minus ll plus 1 over N squared + + align:start position:0% +root of 1 minus ll plus 1 over N squared + + + align:start position:0% +root of 1 minus ll plus 1 over N squared +all these things but that's not so bad + + align:start position:0% +all these things but that's not so bad + + + align:start position:0% +all these things but that's not so bad +you get L times L plus 1 times this + + align:start position:0% +you get L times L plus 1 times this + + + align:start position:0% +you get L times L plus 1 times this +factor that you had in the numerator + + align:start position:0% +factor that you had in the numerator + + + align:start position:0% +factor that you had in the numerator +that still is the same 1 minus L L plus + + align:start position:0% +that still is the same 1 minus L L plus + + + align:start position:0% +that still is the same 1 minus L L plus +1 over N squared + + align:start position:0% +1 over N squared + + + align:start position:0% +1 over N squared +now we're after a kind of an interesting + + align:start position:0% +now we're after a kind of an interesting + + + align:start position:0% +now we're after a kind of an interesting +piece of information the to the sizes of + + align:start position:0% +piece of information the to the sizes of + + + align:start position:0% +piece of information the to the sizes of +the lip so it's worth simplifying what + + align:start position:0% +the lip so it's worth simplifying what + + + align:start position:0% +the lip so it's worth simplifying what +you got this this equation is not nice + + align:start position:0% +you got this this equation is not nice + + + align:start position:0% +you got this this equation is not nice +enough so we're simplifying and in the + + align:start position:0% +enough so we're simplifying and in the + + + align:start position:0% +enough so we're simplifying and in the +denominator you have a plus B times a + + align:start position:0% +denominator you have a plus B times a + + + align:start position:0% +denominator you have a plus B times a +minus B so it's 1 minus 1 minus L L plus + + align:start position:0% +minus B so it's 1 minus 1 minus L L plus + + + align:start position:0% +minus B so it's 1 minus 1 minus L L plus +1 over m squared and the good thing is + + align:start position:0% +1 over m squared and the good thing is + + + align:start position:0% +1 over m squared and the good thing is +that the denominator the 1 cancels and + + align:start position:0% +that the denominator the 1 cancels and + + + align:start position:0% +that the denominator the 1 cancels and +you get the plus L times L plus 1 over N + + align:start position:0% +you get the plus L times L plus 1 over N + + + align:start position:0% +you get the plus L times L plus 1 over N +squared that cancels that one so that at + + align:start position:0% +squared that cancels that one so that at + + + align:start position:0% +squared that cancels that one so that at +the end of the day we get a pretty nice + + align:start position:0% +the end of the day we get a pretty nice + + + align:start position:0% +the end of the day we get a pretty nice +formula + + align:start position:0% + + + + align:start position:0% + +the formulas X is equal to N squared 1 + + align:start position:0% +the formulas X is equal to N squared 1 + + + align:start position:0% +the formulas X is equal to N squared 1 +minus plus 1 minus L times L plus 1 over + + align:start position:0% +minus plus 1 minus L times L plus 1 over + + + align:start position:0% +minus plus 1 minus L times L plus 1 over +N squared like that so if we wish it so + + align:start position:0% +N squared like that so if we wish it so + + + align:start position:0% +N squared like that so if we wish it so +our plus/minus is X multiplied by a + + align:start position:0% +our plus/minus is X multiplied by a + + + align:start position:0% +our plus/minus is X multiplied by a +naught so it's N squared a naught 1 + + align:start position:0% +naught so it's N squared a naught 1 + + + align:start position:0% +naught so it's N squared a naught 1 +minus plus square root of 1 minus L + + align:start position:0% +minus plus square root of 1 minus L + + + align:start position:0% +minus plus square root of 1 minus L +times L plus 1 over N squared okay so + + align:start position:0% +times L plus 1 over N squared okay so + + + align:start position:0% +times L plus 1 over N squared okay so +the ellipse is defined by those two + + align:start position:0% +the ellipse is defined by those two + + + align:start position:0% +the ellipse is defined by those two +values that we have here but the + + align:start position:0% +values that we have here but the + + + align:start position:0% +values that we have here but the +surprising thing is that the some old + + align:start position:0% +surprising thing is that the some old + + + align:start position:0% +surprising thing is that the some old +ellipse and its eccentricity is + + align:start position:0% +ellipse and its eccentricity is + + + align:start position:0% +ellipse and its eccentricity is +dramatically affected by the values of L + + align:start position:0% +dramatically affected by the values of L + + + align:start position:0% +dramatically affected by the values of L +in fact for L equal largest L will be + + align:start position:0% +in fact for L equal largest L will be + + + align:start position:0% +in fact for L equal largest L will be +comparable to n remember L can go up to + + align:start position:0% +comparable to n remember L can go up to + + + align:start position:0% +comparable to n remember L can go up to +n minus 1 so at that point this is + + align:start position:0% +n minus 1 so at that point this is + + + align:start position:0% +n minus 1 so at that point this is +essentially 1 you cancel this and + + align:start position:0% +essentially 1 you cancel this and + + + align:start position:0% +essentially 1 you cancel this and +there's nothing here so there so our + + align:start position:0% +there's nothing here so there so our + + + align:start position:0% +there's nothing here so there so our +plus in our mind has become about the + + align:start position:0% +plus in our mind has become about the + + + align:start position:0% +plus in our mind has become about the +same for l equals n minus 1 our plus is + + align:start position:0% +same for l equals n minus 1 our plus is + + + align:start position:0% +same for l equals n minus 1 our plus is +almost the same as our minus on the + + align:start position:0% +almost the same as our minus on the + + + align:start position:0% +almost the same as our minus on the +orbit is circular completely circular on + + align:start position:0% +orbit is circular completely circular on + + + align:start position:0% +orbit is circular completely circular on +the other hand for l equals 0 the orbit + + align:start position:0% +the other hand for l equals 0 the orbit + + + align:start position:0% +the other hand for l equals 0 the orbit +is completely elliptical in that the + + align:start position:0% +is completely elliptical in that the + + + align:start position:0% +is completely elliptical in that the +radius for l equals 0 this is 0 1 plus + + align:start position:0% +radius for l equals 0 this is 0 1 plus + + + align:start position:0% +radius for l equals 0 this is 0 1 plus +minus 1 so some times is twice this + + align:start position:0% +minus 1 so some times is twice this + + + align:start position:0% +minus 1 so some times is twice this +value sometimes it's 0 + + align:start position:0% +value sometimes it's 0 + + + align:start position:0% +value sometimes it's 0 +so you have the case where our minus can + + align:start position:0% +so you have the case where our minus can + + + align:start position:0% +so you have the case where our minus can +be 0 and you have just an orbit that + + align:start position:0% +be 0 and you have just an orbit that + + + align:start position:0% +be 0 and you have just an orbit that +this like that our minus 0 so extremely + + align:start position:0% +this like that our minus 0 so extremely + + + align:start position:0% +this like that our minus 0 so extremely +elliptical of course that is the semi + + align:start position:0% +elliptical of course that is the semi + + + align:start position:0% +elliptical of course that is the semi +classical approximation so it's more + + align:start position:0% +classical approximation so it's more + + + align:start position:0% +classical approximation so it's more +reliable when you have a reasonable L + + align:start position:0% +reliable when you have a reasonable L + + + align:start position:0% +reliable when you have a reasonable L +undone and finally we can say here for + + align:start position:0% +undone and finally we can say here for + + + align:start position:0% +undone and finally we can say here for +example one interesting thing that our + + align:start position:0% +example one interesting thing that our + + + align:start position:0% +example one interesting thing that our +plus plus our - over 2 which is this our + + align:start position:0% +plus plus our - over 2 which is this our + + + align:start position:0% +plus plus our - over 2 which is this our +plus plus or minus is the total longest + + align:start position:0% +plus plus or minus is the total longest + + + align:start position:0% +plus plus or minus is the total longest +axis of the lips / to the center of the + + align:start position:0% +axis of the lips / to the center of the + + + align:start position:0% +axis of the lips / to the center of the +lips not the focus that distance is + + align:start position:0% +lips not the focus that distance is + + + align:start position:0% +lips not the focus that distance is +independent of L so you'll have N + + align:start position:0% +independent of L so you'll have N + + + align:start position:0% +independent of L so you'll have N +squared a 0 so a typical red burg atom + + align:start position:0% +squared a 0 so a typical red burg atom + + + align:start position:0% +squared a 0 so a typical red burg atom +will have n equal 100 so this is an + + align:start position:0% +will have n equal 100 so this is an + + + align:start position:0% +will have n equal 100 so this is an +example n equal 100 l equals 60 in which + + align:start position:0% +example n equal 100 l equals 60 in which + + + align:start position:0% +example n equal 100 l equals 60 in which +case of the ARP for n equal 100 are plus + + align:start position:0% +case of the ARP for n equal 100 are plus + + + align:start position:0% +case of the ARP for n equal 100 are plus +minus is equal to 10,000 a 0 M squared a + + align:start position:0% +minus is equal to 10,000 a 0 M squared a + + + align:start position:0% +minus is equal to 10,000 a 0 M squared a +0 times this factor which in one case is + + align:start position:0% +0 times this factor which in one case is + + + align:start position:0% +0 times this factor which in one case is +1.8 and in the other case is 0.2 that's + + align:start position:0% +1.8 and in the other case is 0.2 that's + + + align:start position:0% +1.8 and in the other case is 0.2 that's +what you get for L equal 60 and n equal + + align:start position:0% +what you get for L equal 60 and n equal + + + align:start position:0% +what you get for L equal 60 and n equal +100 so this this orbit we have our plus + + align:start position:0% +100 so this this orbit we have our plus + + + align:start position:0% +100 so this this orbit we have our plus +about 18,000 a 0 on arm + + align:start position:0% +about 18,000 a 0 on arm + + + align:start position:0% +about 18,000 a 0 on arm +- about two thousand zero and all of our + + align:start position:0% +- about two thousand zero and all of our + + + align:start position:0% +- about two thousand zero and all of our +orbits satisfy this property that if you + + align:start position:0% +orbits satisfy this property that if you + + + align:start position:0% +orbits satisfy this property that if you +have this hour - an hour plus all of the + + align:start position:0% +have this hour - an hour plus all of the + + + align:start position:0% +have this hour - an hour plus all of the +orbits with different L have the same + + align:start position:0% +orbits with different L have the same + + + align:start position:0% +orbits with different L have the same +hour plus plus or minus so if this is + + align:start position:0% +hour plus plus or minus so if this is + + + align:start position:0% +hour plus plus or minus so if this is +the total length of the major axis when + + align:start position:0% +the total length of the major axis when + + + align:start position:0% +the total length of the major axis when +the orbit becomes circular it's the same + + align:start position:0% +the orbit becomes circular it's the same + + + align:start position:0% +the orbit becomes circular it's the same +and this distance when the orbit becomes + + align:start position:0% +and this distance when the orbit becomes + + + align:start position:0% +and this distance when the orbit becomes +very elliptical is the same as well I + + align:start position:0% +very elliptical is the same as well I + + + align:start position:0% +very elliptical is the same as well I +mentioned last time that this nice + + align:start position:0% +mentioned last time that this nice + + + align:start position:0% +mentioned last time that this nice +property is degeneracy we're here if + + align:start position:0% +property is degeneracy we're here if + + + align:start position:0% +property is degeneracy we're here if +you're keeping em fixed but changing L + + align:start position:0% +you're keeping em fixed but changing L + + + align:start position:0% +you're keeping em fixed but changing L +you're going from all these ellipses + + align:start position:0% +you're going from all these ellipses + + + align:start position:0% +you're going from all these ellipses +this is for l equals n minus 1 and this + + align:start position:0% +this is for l equals n minus 1 and this + + + align:start position:0% +this is for l equals n minus 1 and this +one is for l equals 0 on all these + + align:start position:0% +one is for l equals 0 on all these + + + align:start position:0% +one is for l equals 0 on all these +ellipses are here and they all those are + + align:start position:0% +ellipses are here and they all those are + + + align:start position:0% +ellipses are here and they all those are +all the semi-classical picture of those + + align:start position:0% +all the semi-classical picture of those + + + align:start position:0% +all the semi-classical picture of those +degenerate states in the diagram of the + + align:start position:0% +degenerate states in the diagram of the + + + align:start position:0% +degenerate states in the diagram of the +hydrogen atom the diagram of the + + align:start position:0% +hydrogen atom the diagram of the + + + align:start position:0% +hydrogen atom the diagram of the +hydrogen atom was something like this + + align:start position:0% +hydrogen atom was something like this + + + align:start position:0% +hydrogen atom was something like this +and and you're looking at all the + + align:start position:0% +and and you're looking at all the + + + align:start position:0% +and and you're looking at all the +degenerate states that you have there + + align:start position:0% +degenerate states that you have there + + + align:start position:0% +degenerate states that you have there +and they are degenerate and you would + + align:start position:0% +and they are degenerate and you would + + + align:start position:0% +and they are degenerate and you would +say well why are ellipses that look like + + align:start position:0% +say well why are ellipses that look like + + + align:start position:0% +say well why are ellipses that look like +that the generate well even Kepler + + align:start position:0% +that the generate well even Kepler + + + align:start position:0% +that the generate well even Kepler +apparently knew that in Kepler's laws + + align:start position:0% +apparently knew that in Kepler's laws + + + align:start position:0% +apparently knew that in Kepler's laws +that he observed that the period of + + align:start position:0% +that he observed that the period of + + + align:start position:0% +that he observed that the period of +motion of an orbit just depended on the + + align:start position:0% +motion of an orbit just depended on the + + + align:start position:0% +motion of an orbit just depended on the +semi-major axis so periods are related + + align:start position:0% +semi-major axis so periods are related + + + align:start position:0% +semi-major axis so periods are related +to energy + + align:start position:0% +to energy + + + align:start position:0% +to energy +and it's reasonable the wigs have this + + align:start position:0% +and it's reasonable the wigs have this + + + align:start position:0% +and it's reasonable the wigs have this +thing in quantum mechanics + + align:start position:0% +thing in quantum mechanics + + + align:start position:0% +thing in quantum mechanics +now these degeneracies I want to just + + align:start position:0% +now these degeneracies I want to just + + + align:start position:0% +now these degeneracies I want to just +finish up by emphasizing what you have + + align:start position:0% +finish up by emphasizing what you have + + + align:start position:0% +finish up by emphasizing what you have +here when somebody asks what is the + + align:start position:0% +here when somebody asks what is the + + + align:start position:0% +here when somebody asks what is the +number of states you have here well you + + align:start position:0% +number of states you have here well you + + + align:start position:0% +number of states you have here well you +have to be a little precise on what + + align:start position:0% +have to be a little precise on what + + + align:start position:0% +have to be a little precise on what +you're counting the number of full + + align:start position:0% +you're counting the number of full + + + align:start position:0% +you're counting the number of full +physical states of the quantum system is + + align:start position:0% +physical states of the quantum system is + + + align:start position:0% +physical states of the quantum system is +one here one here one here but each one + + align:start position:0% +one here one here one here but each one + + + align:start position:0% +one here one here one here but each one +of these corresponds to l equals one so + + align:start position:0% +of these corresponds to l equals one so + + + align:start position:0% +of these corresponds to l equals one so +each one of this is triply degenerate + + align:start position:0% +each one of this is triply degenerate + + + align:start position:0% +each one of this is triply degenerate +because M can be minus 1 0 & 1 so here + + align:start position:0% +because M can be minus 1 0 & 1 so here + + + align:start position:0% +because M can be minus 1 0 & 1 so here +three states three stage three states + + align:start position:0% +three states three stage three states + + + align:start position:0% +three states three stage three states +here this is five states five states + + align:start position:0% +here this is five states five states + + + align:start position:0% +here this is five states five states +five stages they'll all have L equal to + + align:start position:0% +five stages they'll all have L equal to + + + align:start position:0% +five stages they'll all have L equal to +and L equal to goes M from minus 2 to + + align:start position:0% +and L equal to goes M from minus 2 to + + + align:start position:0% +and L equal to goes M from minus 2 to +plus 2 so you know we don't actually put + + align:start position:0% +plus 2 so you know we don't actually put + + + align:start position:0% +plus 2 so you know we don't actually put +three things here I think that would be + + align:start position:0% +three things here I think that would be + + + align:start position:0% +three things here I think that would be +confusing we could not put five and we + + align:start position:0% +confusing we could not put five and we + + + align:start position:0% +confusing we could not put five and we +cannot see but it should be remembered + + align:start position:0% +cannot see but it should be remembered + + + align:start position:0% +cannot see but it should be remembered +that this there's the implicit extra + + align:start position:0% +that this there's the implicit extra + + + align:start position:0% +that this there's the implicit extra +degeneracy here associated with the + + align:start position:0% +degeneracy here associated with the + + + align:start position:0% +degeneracy here associated with the +azimuthal quantum number that we + + align:start position:0% +azimuthal quantum number that we + + + align:start position:0% +azimuthal quantum number that we +sometimes just don't represent it in a + + align:start position:0% +sometimes just don't represent it in a + + + align:start position:0% +sometimes just don't represent it in a +figure \ No newline at end of file diff --git a/fn2UGyk5DP4.txt b/fn2UGyk5DP4.txt new file mode 100644 index 0000000000000000000000000000000000000000..e0a6df6256dd77fdbe3a69053b8f7b38bbdc962e --- /dev/null +++ b/fn2UGyk5DP4.txt @@ -0,0 +1,9683 @@ +align:start position:0% + +hi last time we had looked at how we + + align:start position:0% +hi last time we had looked at how we + + + align:start position:0% +hi last time we had looked at how we +might select the compensation for an + + align:start position:0% +might select the compensation for an + + + align:start position:0% +might select the compensation for an +externally compensated operational + + align:start position:0% +externally compensated operational + + + align:start position:0% +externally compensated operational +amplifier as a function of its + + align:start position:0% +amplifier as a function of its + + + align:start position:0% +amplifier as a function of its +application we were using an available + + align:start position:0% +application we were using an available + + + align:start position:0% +application we were using an available +integrated circuit operational amplifier + + align:start position:0% +integrated circuit operational amplifier + + + align:start position:0% +integrated circuit operational amplifier +the type 101 a that is compensated by + + align:start position:0% +the type 101 a that is compensated by + + + align:start position:0% +the type 101 a that is compensated by +means of a minor loop and we discussed + + align:start position:0% +means of a minor loop and we discussed + + + align:start position:0% +means of a minor loop and we discussed +how that minor loop worked and in fact + + align:start position:0% +how that minor loop worked and in fact + + + align:start position:0% +how that minor loop worked and in fact +how we chose compensating in admittances + + align:start position:0% +how we chose compensating in admittances + + + align:start position:0% +how we chose compensating in admittances +or compensating two-port networks as a + + align:start position:0% +or compensating two-port networks as a + + + align:start position:0% +or compensating two-port networks as a +function of the desired closed loop or + + align:start position:0% +function of the desired closed loop or + + + align:start position:0% +function of the desired closed loop or +as a function of the desired open-loop + + align:start position:0% +as a function of the desired open-loop + + + align:start position:0% +as a function of the desired open-loop +transfer function of the amplifier today + + align:start position:0% +transfer function of the amplifier today + + + align:start position:0% +transfer function of the amplifier today +I'd like to continue and look at several + + align:start position:0% +I'd like to continue and look at several + + + align:start position:0% +I'd like to continue and look at several +other types of compensation that we're + + align:start position:0% +other types of compensation that we're + + + align:start position:0% +other types of compensation that we're +able to use if you recall the comparison + + align:start position:0% +able to use if you recall the comparison + + + align:start position:0% +able to use if you recall the comparison +that we were going against was an + + align:start position:0% +that we were going against was an + + + align:start position:0% +that we were going against was an +amplifier that had fixed compensation + + align:start position:0% +amplifier that had fixed compensation + + + align:start position:0% +amplifier that had fixed compensation +something like a 741 type operational + + align:start position:0% +something like a 741 type operational + + + align:start position:0% +something like a 741 type operational +amplifier normally when a manufacturer + + align:start position:0% +amplifier normally when a manufacturer + + + align:start position:0% +amplifier normally when a manufacturer +designs an operational amplifier with + + align:start position:0% +designs an operational amplifier with + + + align:start position:0% +designs an operational amplifier with +fixed compensation he chooses to use + + align:start position:0% +fixed compensation he chooses to use + + + align:start position:0% +fixed compensation he chooses to use +single pole compensation and normally + + align:start position:0% +single pole compensation and normally + + + align:start position:0% +single pole compensation and normally +the constant associated with that single + + align:start position:0% +the constant associated with that single + + + align:start position:0% +the constant associated with that single +pole compensation will be selected so + + align:start position:0% +pole compensation will be selected so + + + align:start position:0% +pole compensation will be selected so +that the amplifier goes through unity + + align:start position:0% +that the amplifier goes through unity + + + align:start position:0% +that the amplifier goes through unity +gain with adequate phase margin as a + + align:start position:0% +gain with adequate phase margin as a + + + align:start position:0% +gain with adequate phase margin as a +consequence when you have such a single + + align:start position:0% +consequence when you have such a single + + + align:start position:0% +consequence when you have such a single +pole Titan amplifier its unity gains + + align:start position:0% +pole Titan amplifier its unity gains + + + align:start position:0% +pole Titan amplifier its unity gains +stable you can use it in the connection + + align:start position:0% +stable you can use it in the connection + + + align:start position:0% +stable you can use it in the connection +that where the output is connected + + align:start position:0% +that where the output is connected + + + align:start position:0% +that where the output is connected +directly back to the inverting input and + + align:start position:0% +directly back to the inverting input and + + + align:start position:0% +directly back to the inverting input and +it will remain stable and that's a + + align:start position:0% +it will remain stable and that's a + + + align:start position:0% +it will remain stable and that's a +perfectly acceptable general + + align:start position:0% +perfectly acceptable general + + + align:start position:0% +perfectly acceptable general +purpose compensation for many + + align:start position:0% +purpose compensation for many + + + align:start position:0% +purpose compensation for many +applications however the difficulty is + + align:start position:0% +applications however the difficulty is + + + align:start position:0% +applications however the difficulty is +that it's really overly conservative for + + align:start position:0% +that it's really overly conservative for + + + align:start position:0% +that it's really overly conservative for +many other and more demanding types of + + align:start position:0% +many other and more demanding types of + + + align:start position:0% +many other and more demanding types of +applications we saw that one of the + + align:start position:0% +applications we saw that one of the + + + align:start position:0% +applications we saw that one of the +things we can do is stay with single + + align:start position:0% +things we can do is stay with single + + + align:start position:0% +things we can do is stay with single +pole compensation that is used a single + + align:start position:0% +pole compensation that is used a single + + + align:start position:0% +pole compensation that is used a single +capacitor to compensate the amplifier + + align:start position:0% +capacitor to compensate the amplifier + + + align:start position:0% +capacitor to compensate the amplifier +but change the magnitude of the + + align:start position:0% +but change the magnitude of the + + + align:start position:0% +but change the magnitude of the +capacitor we found that if we did that + + align:start position:0% +capacitor we found that if we did that + + + align:start position:0% +capacitor we found that if we did that +and in fact changed the capacitor size + + align:start position:0% +and in fact changed the capacitor size + + + align:start position:0% +and in fact changed the capacitor size +as we change the desired closed-loop + + align:start position:0% +as we change the desired closed-loop + + + align:start position:0% +as we change the desired closed-loop +gain we were able to get very dramatic + + align:start position:0% +gain we were able to get very dramatic + + + align:start position:0% +gain we were able to get very dramatic +improvements in the band width of our + + align:start position:0% +improvements in the band width of our + + + align:start position:0% +improvements in the band width of our +externally compensated amplifier + + align:start position:0% +externally compensated amplifier + + + align:start position:0% +externally compensated amplifier +compared to that of a 741 we then looked + + align:start position:0% +compared to that of a 741 we then looked + + + align:start position:0% +compared to that of a 741 we then looked +at another type of compensation to Cole + + align:start position:0% +at another type of compensation to Cole + + + align:start position:0% +at another type of compensation to Cole +compensation where the amplifier + + align:start position:0% +compensation where the amplifier + + + align:start position:0% +compensation where the amplifier +roll-off goes as 1 over s squared at + + align:start position:0% +roll-off goes as 1 over s squared at + + + align:start position:0% +roll-off goes as 1 over s squared at +frequencies well below crossover and + + align:start position:0% +frequencies well below crossover and + + + align:start position:0% +frequencies well below crossover and +then we add a 0 so that crossover is + + align:start position:0% +then we add a 0 so that crossover is + + + align:start position:0% +then we add a 0 so that crossover is +accomplished with a slope of 1 over s + + align:start position:0% +accomplished with a slope of 1 over s + + + align:start position:0% +accomplished with a slope of 1 over s +and again we found out that that sort of + + align:start position:0% +and again we found out that that sort of + + + align:start position:0% +and again we found out that that sort of +compensation could yield very greatly + + align:start position:0% +compensation could yield very greatly + + + align:start position:0% +compensation could yield very greatly +improved the sensitivity over a wide + + align:start position:0% +improved the sensitivity over a wide + + + align:start position:0% +improved the sensitivity over a wide +range of frequencies compared to that + + align:start position:0% +range of frequencies compared to that + + + align:start position:0% +range of frequencies compared to that +which we could achieve with single pole + + align:start position:0% +which we could achieve with single pole + + + align:start position:0% +which we could achieve with single pole +compensation let's consider another + + align:start position:0% +compensation let's consider another + + + align:start position:0% +compensation let's consider another +possible situation suppose we have our + + align:start position:0% +possible situation suppose we have our + + + align:start position:0% +possible situation suppose we have our +operational amplifier and in fact + + align:start position:0% +operational amplifier and in fact + + + align:start position:0% +operational amplifier and in fact +compensated to have a single pole + + align:start position:0% +compensated to have a single pole + + + align:start position:0% +compensated to have a single pole +roll-off so that gets us a 1 over s kind + + align:start position:0% +roll-off so that gets us a 1 over s kind + + + align:start position:0% +roll-off so that gets us a 1 over s kind +of roll-off in our loop and to the + + align:start position:0% +of roll-off in our loop and to the + + + align:start position:0% +of roll-off in our loop and to the +extent that we can ignore other energy + + align:start position:0% +extent that we can ignore other energy + + + align:start position:0% +extent that we can ignore other energy +storage mechanisms in the amplifier + + align:start position:0% +storage mechanisms in the amplifier + + + align:start position:0% +storage mechanisms in the amplifier +while we get approximately 90 degrees of + + align:start position:0% +while we get approximately 90 degrees of + + + align:start position:0% +while we get approximately 90 degrees of +phase margin with this kind of + + align:start position:0% +phase margin with this kind of + + + align:start position:0% +phase margin with this kind of +compensation if we use purely resistive + + align:start position:0% +compensation if we use purely resistive + + + align:start position:0% +compensation if we use purely resistive +feedback however consider what happens + + align:start position:0% +feedback however consider what happens + + + align:start position:0% +feedback however consider what happens +if we load the amplifier with a + + align:start position:0% +if we load the amplifier with a + + + align:start position:0% +if we load the amplifier with a +capacitor and that's a fairly frequently + + align:start position:0% +capacitor and that's a fairly frequently + + + align:start position:0% +capacitor and that's a fairly frequently +occurring situation we can certainly + + align:start position:0% +occurring situation we can certainly + + + align:start position:0% +occurring situation we can certainly +think for example of power supplies + + align:start position:0% +think for example of power supplies + + + align:start position:0% +think for example of power supplies +where a capacitive load is used + + align:start position:0% +where a capacitive load is used + + + align:start position:0% +where a capacitive load is used +routinely we've already looked at one + + align:start position:0% +routinely we've already looked at one + + + align:start position:0% +routinely we've already looked at one +aspect of that problem but if we're not + + align:start position:0% +aspect of that problem but if we're not + + + align:start position:0% +aspect of that problem but if we're not +able to force a dominant pole at the + + align:start position:0% +able to force a dominant pole at the + + + align:start position:0% +able to force a dominant pole at the +output as we suggested earlier why here + + align:start position:0% +output as we suggested earlier why here + + + align:start position:0% +output as we suggested earlier why here +we have a situation where we have the + + align:start position:0% +we have a situation where we have the + + + align:start position:0% +we have a situation where we have the +passive load another possibility is a + + align:start position:0% +passive load another possibility is a + + + align:start position:0% +passive load another possibility is a +circuit known as a sample-and-hold + + align:start position:0% +circuit known as a sample-and-hold + + + align:start position:0% +circuit known as a sample-and-hold +where one takes an amplifier connects a + + align:start position:0% +where one takes an amplifier connects a + + + align:start position:0% +where one takes an amplifier connects a +capacitor to it so that the capacitor + + align:start position:0% +capacitor to it so that the capacitor + + + align:start position:0% +capacitor to it so that the capacitor +can be charged to some input voltage + + align:start position:0% +can be charged to some input voltage + + + align:start position:0% +can be charged to some input voltage +applied to the amplifier and then at + + align:start position:0% +applied to the amplifier and then at + + + align:start position:0% +applied to the amplifier and then at +some later time removes the + + align:start position:0% +some later time removes the + + + align:start position:0% +some later time removes the +passenger so that the value of the + + align:start position:0% +passenger so that the value of the + + + align:start position:0% +passenger so that the value of the +voltage is maintained that sort of a + + align:start position:0% +voltage is maintained that sort of a + + + align:start position:0% +voltage is maintained that sort of a +circuit is called the sample-and-hold + + align:start position:0% +circuit is called the sample-and-hold + + + align:start position:0% +circuit is called the sample-and-hold +but again it involves a capacitive load + + align:start position:0% +but again it involves a capacitive load + + + align:start position:0% +but again it involves a capacitive load +on an operational amplifier the + + align:start position:0% +on an operational amplifier the + + + align:start position:0% +on an operational amplifier the +operational amplifier has finite output + + align:start position:0% +operational amplifier has finite output + + + align:start position:0% +operational amplifier has finite output +resistance and consequently adding a + + align:start position:0% +resistance and consequently adding a + + + align:start position:0% +resistance and consequently adding a +capacitor to its output gives us an + + align:start position:0% +capacitor to its output gives us an + + + align:start position:0% +capacitor to its output gives us an +additional pole and so now we have a two + + align:start position:0% +additional pole and so now we have a two + + + align:start position:0% +additional pole and so now we have a two +pole kind of loop transmission and + + align:start position:0% +pole kind of loop transmission and + + + align:start position:0% +pole kind of loop transmission and +certainly if the additional pole that we + + align:start position:0% +certainly if the additional pole that we + + + align:start position:0% +certainly if the additional pole that we +add occurs well below crossover the + + align:start position:0% +add occurs well below crossover the + + + align:start position:0% +add occurs well below crossover the +stability of the amplifier is very + + align:start position:0% +stability of the amplifier is very + + + align:start position:0% +stability of the amplifier is very +severely compromised I'd like to look at + + align:start position:0% +severely compromised I'd like to look at + + + align:start position:0% +severely compromised I'd like to look at +that we have the same demonstration + + align:start position:0% +that we have the same demonstration + + + align:start position:0% +that we have the same demonstration +setup that we used last time just a + + align:start position:0% +setup that we used last time just a + + + align:start position:0% +setup that we used last time just a +power supply a signal generator which in + + align:start position:0% +power supply a signal generator which in + + + align:start position:0% +power supply a signal generator which in +this case will be applying a square wave + + align:start position:0% +this case will be applying a square wave + + + align:start position:0% +this case will be applying a square wave +to the amplifier we're testing an + + align:start position:0% +to the amplifier we're testing an + + + align:start position:0% +to the amplifier we're testing an +oscilloscope to look at the output of + + align:start position:0% +oscilloscope to look at the output of + + + align:start position:0% +oscilloscope to look at the output of +the amplifier and this time we're using + + align:start position:0% +the amplifier and this time we're using + + + align:start position:0% +the amplifier and this time we're using +this particular amplifier and have it + + align:start position:0% +this particular amplifier and have it + + + align:start position:0% +this particular amplifier and have it +connected simply as a unity gain + + align:start position:0% +connected simply as a unity gain + + + align:start position:0% +connected simply as a unity gain +follower in other words we apply the + + align:start position:0% +follower in other words we apply the + + + align:start position:0% +follower in other words we apply the +input signal to the non-inverting input + + align:start position:0% +input signal to the non-inverting input + + + align:start position:0% +input signal to the non-inverting input +terminal of the operational amplifier we + + align:start position:0% +terminal of the operational amplifier we + + + align:start position:0% +terminal of the operational amplifier we +take the output and bring it directly + + align:start position:0% +take the output and bring it directly + + + align:start position:0% +take the output and bring it directly +back to the inverting input terminal and + + align:start position:0% +back to the inverting input terminal and + + + align:start position:0% +back to the inverting input terminal and +at present we have the amplifier + + align:start position:0% +at present we have the amplifier + + + align:start position:0% +at present we have the amplifier +compensated for single pole operation + + align:start position:0% +compensated for single pole operation + + + align:start position:0% +compensated for single pole operation +and we see the resultant step response + + align:start position:0% +and we see the resultant step response + + + align:start position:0% +and we see the resultant step response +on the oscilloscope we're using about a + + align:start position:0% +on the oscilloscope we're using about a + + + align:start position:0% +on the oscilloscope we're using about a +twenty Pico farad capacitor with this + + align:start position:0% +twenty Pico farad capacitor with this + + + align:start position:0% +twenty Pico farad capacitor with this +particular amplifier which is the same + + align:start position:0% +particular amplifier which is the same + + + align:start position:0% +particular amplifier which is the same +one we used in the last series of + + align:start position:0% +one we used in the last series of + + + align:start position:0% +one we used in the last series of +demonstrations we get a rise time ten to + + align:start position:0% +demonstrations we get a rise time ten to + + + align:start position:0% +demonstrations we get a rise time ten to +90 percent rise time of about 200 + + align:start position:0% +90 percent rise time of about 200 + + + align:start position:0% +90 percent rise time of about 200 +nanoseconds with that single pole with + + align:start position:0% +nanoseconds with that single pole with + + + align:start position:0% +nanoseconds with that single pole with +that value for single pole compensation + + align:start position:0% +that value for single pole compensation + + + align:start position:0% +that value for single pole compensation +implying with the crossover frequency + + align:start position:0% +implying with the crossover frequency + + + align:start position:0% +implying with the crossover frequency +for this configuration is somewhere in + + align:start position:0% +for this configuration is somewhere in + + + align:start position:0% +for this configuration is somewhere in +the order of two megahertz and this is + + align:start position:0% +the order of two megahertz and this is + + + align:start position:0% +the order of two megahertz and this is +operating without any capacitive load + + align:start position:0% +operating without any capacitive load + + + align:start position:0% +operating without any capacitive load +now let's see what happens when I throw + + align:start position:0% +now let's see what happens when I throw + + + align:start position:0% +now let's see what happens when I throw +this switch and first we'll connect 0.01 + + align:start position:0% +this switch and first we'll connect 0.01 + + + align:start position:0% +this switch and first we'll connect 0.01 +micro farad capacitor to the output of + + align:start position:0% +micro farad capacitor to the output of + + + align:start position:0% +micro farad capacitor to the output of +the amplifier and we notice that in + + align:start position:0% +the amplifier and we notice that in + + + align:start position:0% +the amplifier and we notice that in +addition to the we get a tremendous + + align:start position:0% +addition to the we get a tremendous + + + align:start position:0% +addition to the we get a tremendous +amount of overshoot we get a very much + + align:start position:0% +amount of overshoot we get a very much + + + align:start position:0% +amount of overshoot we get a very much +more poorly damped system than we had + + align:start position:0% +more poorly damped system than we had + + + align:start position:0% +more poorly damped system than we had +before comparing again these two cases + + align:start position:0% +before comparing again these two cases + + + align:start position:0% +before comparing again these two cases +here's no capacitive load here's a no 1 + + align:start position:0% +here's no capacitive load here's a no 1 + + + align:start position:0% +here's no capacitive load here's a no 1 +microfarad capacitive load applied to + + align:start position:0% +microfarad capacitive load applied to + + + align:start position:0% +microfarad capacitive load applied to +the amplifier we get a considerable + + align:start position:0% +the amplifier we get a considerable + + + align:start position:0% +the amplifier we get a considerable +overshoot quite a poorly damped response + + align:start position:0% +overshoot quite a poorly damped response + + + align:start position:0% +overshoot quite a poorly damped response +and the settling time is of course very + + align:start position:0% +and the settling time is of course very + + + align:start position:0% +and the settling time is of course very +very dramatically increased before + + align:start position:0% +very dramatically increased before + + + align:start position:0% +very dramatically increased before +settling time was with several hundred + + align:start position:0% +settling time was with several hundred + + + align:start position:0% +settling time was with several hundred +nano seconds here we see that the + + align:start position:0% +nano seconds here we see that the + + + align:start position:0% +nano seconds here we see that the +amplifier is still ringing at ten + + align:start position:0% +amplifier is still ringing at ten + + + align:start position:0% +amplifier is still ringing at ten +microseconds the horizontal division one + + align:start position:0% +microseconds the horizontal division one + + + align:start position:0% +microseconds the horizontal division one +horizontal division corresponds to two + + align:start position:0% +horizontal division corresponds to two + + + align:start position:0% +horizontal division corresponds to two +microseconds so we see that the + + align:start position:0% +microseconds so we see that the + + + align:start position:0% +microseconds so we see that the +amplifier is ringing for at least ten + + align:start position:0% +amplifier is ringing for at least ten + + + align:start position:0% +amplifier is ringing for at least ten +microseconds we can make matters even + + align:start position:0% +microseconds we can make matters even + + + align:start position:0% +microseconds we can make matters even +worse let me load the amplifier with a + + align:start position:0% +worse let me load the amplifier with a + + + align:start position:0% +worse let me load the amplifier with a +tenth of a micro farad capacitor and we + + align:start position:0% +tenth of a micro farad capacitor and we + + + align:start position:0% +tenth of a micro farad capacitor and we +do that we'll have to slow down the + + align:start position:0% +do that we'll have to slow down the + + + align:start position:0% +do that we'll have to slow down the +signal generator just a bit here again + + align:start position:0% +signal generator just a bit here again + + + align:start position:0% +signal generator just a bit here again +we notice a further deterioration of + + align:start position:0% +we notice a further deterioration of + + + align:start position:0% +we notice a further deterioration of +relative stability considerable + + align:start position:0% +relative stability considerable + + + align:start position:0% +relative stability considerable +overshoot we're now at ten microseconds + + align:start position:0% +overshoot we're now at ten microseconds + + + align:start position:0% +overshoot we're now at ten microseconds +per division and we notice that the + + align:start position:0% +per division and we notice that the + + + align:start position:0% +per division and we notice that the +response still is wiggling a hundred + + align:start position:0% +response still is wiggling a hundred + + + align:start position:0% +response still is wiggling a hundred +microseconds later so the settling time + + align:start position:0% +microseconds later so the settling time + + + align:start position:0% +microseconds later so the settling time +of this amplifier has been deteriorated + + align:start position:0% +of this amplifier has been deteriorated + + + align:start position:0% +of this amplifier has been deteriorated +to more than one hundred microseconds + + align:start position:0% +to more than one hundred microseconds + + + align:start position:0% +to more than one hundred microseconds +with the addition of the tenth micro + + align:start position:0% +with the addition of the tenth micro + + + align:start position:0% +with the addition of the tenth micro +farad load capacitor we can also notice + + align:start position:0% +farad load capacitor we can also notice + + + align:start position:0% +farad load capacitor we can also notice +the ring frequency we're now at at two + + align:start position:0% +the ring frequency we're now at at two + + + align:start position:0% +the ring frequency we're now at at two +microseconds per division so the ring + + align:start position:0% +microseconds per division so the ring + + + align:start position:0% +microseconds per division so the ring +frequency is somewhere in the order of + + align:start position:0% +frequency is somewhere in the order of + + + align:start position:0% +frequency is somewhere in the order of +200 kilohertz for this particular + + align:start position:0% +200 kilohertz for this particular + + + align:start position:0% +200 kilohertz for this particular +amplifier we can explain why that + + align:start position:0% +amplifier we can explain why that + + + align:start position:0% +amplifier we can explain why that +happens let's look at the amplifier + + align:start position:0% +happens let's look at the amplifier + + + align:start position:0% +happens let's look at the amplifier +open-loop transfer function in the + + align:start position:0% +open-loop transfer function in the + + + align:start position:0% +open-loop transfer function in the +absence of a capacitive load here we we + + align:start position:0% +absence of a capacitive load here we we + + + align:start position:0% +absence of a capacitive load here we we +have chosen single pole compensation for + + align:start position:0% +have chosen single pole compensation for + + + align:start position:0% +have chosen single pole compensation for +this particular amplifier with the + + align:start position:0% +this particular amplifier with the + + + align:start position:0% +this particular amplifier with the +twenty Pico farad compensating capacitor + + align:start position:0% +twenty Pico farad compensating capacitor + + + align:start position:0% +twenty Pico farad compensating capacitor +that we're using crossover occurs at + + align:start position:0% +that we're using crossover occurs at + + + align:start position:0% +that we're using crossover occurs at +about two megahertz or 1.2 times 10 to + + align:start position:0% +about two megahertz or 1.2 times 10 to + + + align:start position:0% +about two megahertz or 1.2 times 10 to +the seventh radians per second so this + + align:start position:0% +the seventh radians per second so this + + + align:start position:0% +the seventh radians per second so this +is the open-loop transfer function of + + align:start position:0% +is the open-loop transfer function of + + + align:start position:0% +is the open-loop transfer function of +the amplifier a single pole roll-off + + align:start position:0% +the amplifier a single pole roll-off + + + align:start position:0% +the amplifier a single pole roll-off +over a wide range of frequencies when we + + align:start position:0% +over a wide range of frequencies when we + + + align:start position:0% +over a wide range of frequencies when we +have no capacitive load the output + + align:start position:0% +have no capacitive load the output + + + align:start position:0% +have no capacitive load the output +resistance of the amplifier is somewhere + + align:start position:0% +resistance of the amplifier is somewhere + + + align:start position:0% +resistance of the amplifier is somewhere +on the order of a hundred ohms and + + align:start position:0% +on the order of a hundred ohms and + + + align:start position:0% +on the order of a hundred ohms and +consequently when we load the amplifier + + align:start position:0% +consequently when we load the amplifier + + + align:start position:0% +consequently when we load the amplifier +with a tenth of a micro farad capacitor + + align:start position:0% +with a tenth of a micro farad capacitor + + + align:start position:0% +with a tenth of a micro farad capacitor +we'll put in another poll with a time + + align:start position:0% +we'll put in another poll with a time + + + align:start position:0% +we'll put in another poll with a time +constant of 10 microseconds in other + + align:start position:0% +constant of 10 microseconds in other + + + align:start position:0% +constant of 10 microseconds in other +words we'll add a poll at 10 to the + + align:start position:0% +words we'll add a poll at 10 to the + + + align:start position:0% +words we'll add a poll at 10 to the +fifth radians per second back about in + + align:start position:0% +fifth radians per second back about in + + + align:start position:0% +fifth radians per second back about in +here if we add one additional poll to + + align:start position:0% +here if we add one additional poll to + + + align:start position:0% +here if we add one additional poll to +the open-loop transfer function of the + + align:start position:0% +the open-loop transfer function of the + + + align:start position:0% +the open-loop transfer function of the +amplifier our resultant a of s will be + + align:start position:0% +amplifier our resultant a of s will be + + + align:start position:0% +amplifier our resultant a of s will be +this we notice that the magnitude of the + + align:start position:0% +this we notice that the magnitude of the + + + align:start position:0% +this we notice that the magnitude of the +open-loop gain at the frequency where + + align:start position:0% +open-loop gain at the frequency where + + + align:start position:0% +open-loop gain at the frequency where +the pole is located is about 120 it's + + align:start position:0% +the pole is located is about 120 it's + + + align:start position:0% +the pole is located is about 120 it's +back a factor of 120 from the unity gain + + align:start position:0% +back a factor of 120 from the unity gain + + + align:start position:0% +back a factor of 120 from the unity gain +frequency that results with sing it with + + align:start position:0% +frequency that results with sing it with + + + align:start position:0% +frequency that results with sing it with +a single pole roll-off we cross over at + + align:start position:0% +a single pole roll-off we cross over at + + + align:start position:0% +a single pole roll-off we cross over at +the geometric mean between this + + align:start position:0% +the geometric mean between this + + + align:start position:0% +the geometric mean between this +frequency and the original frequency + + align:start position:0% +frequency and the original frequency + + + align:start position:0% +frequency and the original frequency +since where the original crossover + + align:start position:0% +since where the original crossover + + + align:start position:0% +since where the original crossover +frequency since we're falling off as 1 + + align:start position:0% +frequency since we're falling off as 1 + + + align:start position:0% +frequency since we're falling off as 1 +over s squared and so we cross over + + align:start position:0% +over s squared and so we cross over + + + align:start position:0% +over s squared and so we cross over +somewhere on the order of 10 to the 6th + + align:start position:0% +somewhere on the order of 10 to the 6th + + + align:start position:0% +somewhere on the order of 10 to the 6th +radians per second or maybe a little bit + + align:start position:0% +radians per second or maybe a little bit + + + align:start position:0% +radians per second or maybe a little bit +higher than that and that corresponds to + + align:start position:0% +higher than that and that corresponds to + + + align:start position:0% +higher than that and that corresponds to +the roughly 200 kilohertz ring frequency + + align:start position:0% +the roughly 200 kilohertz ring frequency + + + align:start position:0% +the roughly 200 kilohertz ring frequency +that we saw on the oscilloscope trace + + align:start position:0% +that we saw on the oscilloscope trace + + + align:start position:0% +that we saw on the oscilloscope trace +furthermore notice that we cross over + + align:start position:0% +furthermore notice that we cross over + + + align:start position:0% +furthermore notice that we cross over +after we've been rolling off as 1 over s + + align:start position:0% +after we've been rolling off as 1 over s + + + align:start position:0% +after we've been rolling off as 1 over s +squared for about a factor of 10 from + + align:start position:0% +squared for about a factor of 10 from + + + align:start position:0% +squared for about a factor of 10 from +this frequency to this one there's been + + align:start position:0% +this frequency to this one there's been + + + align:start position:0% +this frequency to this one there's been +a long one over s squared region and if + + align:start position:0% +a long one over s squared region and if + + + align:start position:0% +a long one over s squared region and if +you consider the implications of that + + align:start position:0% +you consider the implications of that + + + align:start position:0% +you consider the implications of that +why we would anticipate a phase margin + + align:start position:0% +why we would anticipate a phase margin + + + align:start position:0% +why we would anticipate a phase margin +of somewhere in the order of a tenth of + + align:start position:0% +of somewhere in the order of a tenth of + + + align:start position:0% +of somewhere in the order of a tenth of +a Radian roughly 5 degrees because we're + + align:start position:0% +a Radian roughly 5 degrees because we're + + + align:start position:0% +a Radian roughly 5 degrees because we're +crossing over a factor of 10 beyond the + + align:start position:0% +crossing over a factor of 10 beyond the + + + align:start position:0% +crossing over a factor of 10 beyond the +second pole we'd certainly expect that + + align:start position:0% +second pole we'd certainly expect that + + + align:start position:0% +second pole we'd certainly expect that +that sort of phase margin would result + + align:start position:0% +that sort of phase margin would result + + + align:start position:0% +that sort of phase margin would result +in very marginally stable performance + + align:start position:0% +in very marginally stable performance + + + align:start position:0% +in very marginally stable performance +and that's what we see in the step + + align:start position:0% +and that's what we see in the step + + + align:start position:0% +and that's what we see in the step +response + + align:start position:0% +response + + + align:start position:0% +response +well how might we improve the situation + + align:start position:0% +well how might we improve the situation + + + align:start position:0% +well how might we improve the situation +the thing to do is to attempt to make + + align:start position:0% +the thing to do is to attempt to make + + + align:start position:0% +the thing to do is to attempt to make +the open-loop transfer function of the + + align:start position:0% +the open-loop transfer function of the + + + align:start position:0% +the open-loop transfer function of the +amplifier in the absence of load include + + align:start position:0% +amplifier in the absence of load include + + + align:start position:0% +amplifier in the absence of load include +a 0 in other words start out with an + + align:start position:0% +a 0 in other words start out with an + + + align:start position:0% +a 0 in other words start out with an +open-loop transfer function that rolls + + align:start position:0% +open-loop transfer function that rolls + + + align:start position:0% +open-loop transfer function that rolls +off is 1 over s at low frequencies but + + align:start position:0% +off is 1 over s at low frequencies but + + + align:start position:0% +off is 1 over s at low frequencies but +then at some higher frequency flattens + + align:start position:0% +then at some higher frequency flattens + + + align:start position:0% +then at some higher frequency flattens +out if we can do that if we can add a 0 + + align:start position:0% +out if we can do that if we can add a 0 + + + align:start position:0% +out if we can do that if we can add a 0 +we presumably could use that 0 to + + align:start position:0% +we presumably could use that 0 to + + + align:start position:0% +we presumably could use that 0 to +somehow + + align:start position:0% +somehow + + + align:start position:0% +somehow +offset the effects of the pole that we + + align:start position:0% +offset the effects of the pole that we + + + align:start position:0% +offset the effects of the pole that we +get when we add capacitive loading we + + align:start position:0% +get when we add capacitive loading we + + + align:start position:0% +get when we add capacitive loading we +might for example attempt to line up the + + align:start position:0% +might for example attempt to line up the + + + align:start position:0% +might for example attempt to line up the +zero in the unloaded open-loop transfer + + align:start position:0% +zero in the unloaded open-loop transfer + + + align:start position:0% +zero in the unloaded open-loop transfer +function with the pole actually we find + + align:start position:0% +function with the pole actually we find + + + align:start position:0% +function with the pole actually we find +out that there may be a little better + + align:start position:0% +out that there may be a little better + + + align:start position:0% +out that there may be a little better +thing to do than that but but + + align:start position:0% +thing to do than that but but + + + align:start position:0% +thing to do than that but but +effectively what we can do is use this + + align:start position:0% +effectively what we can do is use this + + + align:start position:0% +effectively what we can do is use this +zero in an attempt to offset the effect + + align:start position:0% +zero in an attempt to offset the effect + + + align:start position:0% +zero in an attempt to offset the effect +of the pole that results from capacitive + + align:start position:0% +of the pole that results from capacitive + + + align:start position:0% +of the pole that results from capacitive +loading if we can choose compensating + + align:start position:0% +loading if we can choose compensating + + + align:start position:0% +loading if we can choose compensating +admittance or a compensating network to + + align:start position:0% +admittance or a compensating network to + + + align:start position:0% +admittance or a compensating network to +give us this sort of ideal open-loop + + align:start position:0% +give us this sort of ideal open-loop + + + align:start position:0% +give us this sort of ideal open-loop +transfer function we can look at the + + align:start position:0% +transfer function we can look at the + + + align:start position:0% +transfer function we can look at the +result in a little bit more detail here + + align:start position:0% +result in a little bit more detail here + + + align:start position:0% +result in a little bit more detail here +here again we have the assumed + + align:start position:0% +here again we have the assumed + + + align:start position:0% +here again we have the assumed +uncompensated transfer function of the + + align:start position:0% +uncompensated transfer function of the + + + align:start position:0% +uncompensated transfer function of the +amplifier we have the approximation the + + align:start position:0% +amplifier we have the approximation the + + + align:start position:0% +amplifier we have the approximation the +ideal open-loop transfer function that's + + align:start position:0% +ideal open-loop transfer function that's + + + align:start position:0% +ideal open-loop transfer function that's +simply related to the transconductance + + align:start position:0% +simply related to the transconductance + + + align:start position:0% +simply related to the transconductance +of the first stage and the compensating + + align:start position:0% +of the first stage and the compensating + + + align:start position:0% +of the first stage and the compensating +admittance or the short-circuit transfer + + align:start position:0% +admittance or the short-circuit transfer + + + align:start position:0% +admittance or the short-circuit transfer +admittance of the compensating Network + + align:start position:0% +admittance of the compensating Network + + + align:start position:0% +admittance of the compensating Network +that approximation where we'd like to + + align:start position:0% +that approximation where we'd like to + + + align:start position:0% +that approximation where we'd like to +have have a 1 over s roll-off at low + + align:start position:0% +have have a 1 over s roll-off at low + + + align:start position:0% +have have a 1 over s roll-off at low +frequencies and then flattened out at + + align:start position:0% +frequencies and then flattened out at + + + align:start position:0% +frequencies and then flattened out at +higher frequencies the intersection of + + align:start position:0% +higher frequencies the intersection of + + + align:start position:0% +higher frequencies the intersection of +that with the uncompensated curve + + align:start position:0% +that with the uncompensated curve + + + align:start position:0% +that with the uncompensated curve +choosing the lower of the curves at all + + align:start position:0% +choosing the lower of the curves at all + + + align:start position:0% +choosing the lower of the curves at all +frequencies gives us a good estimation + + align:start position:0% +frequencies gives us a good estimation + + + align:start position:0% +frequencies gives us a good estimation +of the actual open-loop gain of the + + align:start position:0% +of the actual open-loop gain of the + + + align:start position:0% +of the actual open-loop gain of the +amplifier and so between possibly this + + align:start position:0% +amplifier and so between possibly this + + + align:start position:0% +amplifier and so between possibly this +frequency and this frequency we find out + + align:start position:0% +frequency and this frequency we find out + + + align:start position:0% +frequency and this frequency we find out +that we are able to control the transfer + + align:start position:0% +that we are able to control the transfer + + + align:start position:0% +that we are able to control the transfer +function of the amplifier by the + + align:start position:0% +function of the amplifier by the + + + align:start position:0% +function of the amplifier by the +compensating Network we get the single + + align:start position:0% +compensating Network we get the single + + + align:start position:0% +compensating Network we get the single +pole roll-off at low frequencies the + + align:start position:0% +pole roll-off at low frequencies the + + + align:start position:0% +pole roll-off at low frequencies the +zero that we hope to use to compensate + + align:start position:0% +zero that we hope to use to compensate + + + align:start position:0% +zero that we hope to use to compensate +the pole resulting from capacitive + + align:start position:0% +the pole resulting from capacitive + + + align:start position:0% +the pole resulting from capacitive +loading again we see the effect on on + + align:start position:0% +loading again we see the effect on on + + + align:start position:0% +loading again we see the effect on on +phase the uncompensated phase of course + + align:start position:0% +phase the uncompensated phase of course + + + align:start position:0% +phase the uncompensated phase of course +rolling off are the approximation + + align:start position:0% +rolling off are the approximation + + + align:start position:0% +rolling off are the approximation +indicating we'd have minus 90 degrees a + + align:start position:0% +indicating we'd have minus 90 degrees a + + + align:start position:0% +indicating we'd have minus 90 degrees a +phase shift at low frequencies + + align:start position:0% +phase shift at low frequencies + + + align:start position:0% +phase shift at low frequencies +corresponding to the 1 over s roll-off + + align:start position:0% +corresponding to the 1 over s roll-off + + + align:start position:0% +corresponding to the 1 over s roll-off +and increasing actually to 0 degrees in + + align:start position:0% +and increasing actually to 0 degrees in + + + align:start position:0% +and increasing actually to 0 degrees in +reality we don't achieve that but we get + + align:start position:0% +reality we don't achieve that but we get + + + align:start position:0% +reality we don't achieve that but we get +a an actual compensated phase curve that + + align:start position:0% +a an actual compensated phase curve that + + + align:start position:0% +a an actual compensated phase curve that +looks something like Slyke so at very + + align:start position:0% +looks something like Slyke so at very + + + align:start position:0% +looks something like Slyke so at very +low frequencies at 0 it then dips down + + align:start position:0% +low frequencies at 0 it then dips down + + + align:start position:0% +low frequencies at 0 it then dips down +close to minus 90 + + align:start position:0% +close to minus 90 + + + align:start position:0% +close to minus 90 +agrees over a wide range of frequencies + + align:start position:0% +agrees over a wide range of frequencies + + + align:start position:0% +agrees over a wide range of frequencies +heads back more positive in the vicinity + + align:start position:0% +heads back more positive in the vicinity + + + align:start position:0% +heads back more positive in the vicinity +of the zero and eventually falls off + + align:start position:0% +of the zero and eventually falls off + + + align:start position:0% +of the zero and eventually falls off +again at higher frequencies so this then + + align:start position:0% +again at higher frequencies so this then + + + align:start position:0% +again at higher frequencies so this then +is the kind of an open-loop transfer + + align:start position:0% +is the kind of an open-loop transfer + + + align:start position:0% +is the kind of an open-loop transfer +function we'd expect from the amplifier + + align:start position:0% +function we'd expect from the amplifier + + + align:start position:0% +function we'd expect from the amplifier +if we could select a compensating or a + + align:start position:0% +if we could select a compensating or a + + + align:start position:0% +if we could select a compensating or a +compensating network that had a + + align:start position:0% +compensating network that had a + + + align:start position:0% +compensating network that had a +short-circuit transfer admittance such + + align:start position:0% +short-circuit transfer admittance such + + + align:start position:0% +short-circuit transfer admittance such +the G sub M over to YC had this form how + + align:start position:0% +the G sub M over to YC had this form how + + + align:start position:0% +the G sub M over to YC had this form how +do we accomplish that well let's see + + align:start position:0% +do we accomplish that well let's see + + + align:start position:0% +do we accomplish that well let's see +we'd like to have G M over to YC of s + + align:start position:0% +we'd like to have G M over to YC of s + + + align:start position:0% +we'd like to have G M over to YC of s +have the general form K over s times a0 + + align:start position:0% +have the general form K over s times a0 + + + align:start position:0% +have the general form K over s times a0 +we can do that without even resorting to + + align:start position:0% +we can do that without even resorting to + + + align:start position:0% +we can do that without even resorting to +a true two-port we can do it is simply a + + align:start position:0% +a true two-port we can do it is simply a + + + align:start position:0% +a true two-port we can do it is simply a +series combination of a resistor and a + + align:start position:0% +series combination of a resistor and a + + + align:start position:0% +series combination of a resistor and a +capacitor if we look at the simple RC + + align:start position:0% +capacitor if we look at the simple RC + + + align:start position:0% +capacitor if we look at the simple RC +connection and write its admittance we + + align:start position:0% +connection and write its admittance we + + + align:start position:0% +connection and write its admittance we +find that the admittance of that network + + align:start position:0% +find that the admittance of that network + + + align:start position:0% +find that the admittance of that network +is simply CS over RCS plus 1 + + align:start position:0% +is simply CS over RCS plus 1 + + + align:start position:0% +is simply CS over RCS plus 1 +consequently G sub M over 2 YC has the + + align:start position:0% +consequently G sub M over 2 YC has the + + + align:start position:0% +consequently G sub M over 2 YC has the +general form that we'd like and what we + + align:start position:0% +general form that we'd like and what we + + + align:start position:0% +general form that we'd like and what we +might do then is for example choose a 0 + + align:start position:0% +might do then is for example choose a 0 + + + align:start position:0% +might do then is for example choose a 0 +location as I've shown it somewhere out + + align:start position:0% +location as I've shown it somewhere out + + + align:start position:0% +location as I've shown it somewhere out +in here if we did that we'd use that + + align:start position:0% +in here if we did that we'd use that + + + align:start position:0% +in here if we did that we'd use that +zero from the compensated amplifier + + align:start position:0% +zero from the compensated amplifier + + + align:start position:0% +zero from the compensated amplifier +open-loop transfer function in the + + align:start position:0% +open-loop transfer function in the + + + align:start position:0% +open-loop transfer function in the +absence of load we use that zero to + + align:start position:0% +absence of load we use that zero to + + + align:start position:0% +absence of load we use that zero to +offset the effects of the pole that + + align:start position:0% +offset the effects of the pole that + + + align:start position:0% +offset the effects of the pole that +resulted from capacitive loading as a + + align:start position:0% +resulted from capacitive loading as a + + + align:start position:0% +resulted from capacitive loading as a +result R over overall loop transmission + + align:start position:0% +result R over overall loop transmission + + + align:start position:0% +result R over overall loop transmission +or the negative of the loop transmission + + align:start position:0% +or the negative of the loop transmission + + + align:start position:0% +or the negative of the loop transmission +might look something like that the hope + + align:start position:0% +might look something like that the hope + + + align:start position:0% +might look something like that the hope +is that of course we greatly improve the + + align:start position:0% +is that of course we greatly improve the + + + align:start position:0% +is that of course we greatly improve the +phase margin by virtue of having added + + align:start position:0% +phase margin by virtue of having added + + + align:start position:0% +phase margin by virtue of having added +this zero to the loop transmission let's + + align:start position:0% +this zero to the loop transmission let's + + + align:start position:0% +this zero to the loop transmission let's +see how that works + + align:start position:0% + + + + align:start position:0% + +here again we have the amplifier as we + + align:start position:0% +here again we have the amplifier as we + + + align:start position:0% +here again we have the amplifier as we +left it with the tenth micro farad + + align:start position:0% +left it with the tenth micro farad + + + align:start position:0% +left it with the tenth micro farad +capacitor load and considerable ringing + + align:start position:0% +capacitor load and considerable ringing + + + align:start position:0% +capacitor load and considerable ringing +and what I'm going to do is add a + + align:start position:0% +and what I'm going to do is add a + + + align:start position:0% +and what I'm going to do is add a +network that consists of a series + + align:start position:0% +network that consists of a series + + + align:start position:0% +network that consists of a series +connection of a resistor and a capacitor + + align:start position:0% +connection of a resistor and a capacitor + + + align:start position:0% +connection of a resistor and a capacitor +actually there's a third little + + align:start position:0% +actually there's a third little + + + align:start position:0% +actually there's a third little +capacitor here and I'll apologize for + + align:start position:0% +capacitor here and I'll apologize for + + + align:start position:0% +capacitor here and I'll apologize for +that we'll see in a moment why we want + + align:start position:0% +that we'll see in a moment why we want + + + align:start position:0% +that we'll see in a moment why we want +to have that that third element to the + + align:start position:0% +to have that that third element to the + + + align:start position:0% +to have that that third element to the +the second capacitor woman we'll see + + align:start position:0% +the second capacitor woman we'll see + + + align:start position:0% +the second capacitor woman we'll see +what we do with that in a moment but + + align:start position:0% +what we do with that in a moment but + + + align:start position:0% +what we do with that in a moment but +starting out we simply have the series + + align:start position:0% +starting out we simply have the series + + + align:start position:0% +starting out we simply have the series +resistor capacitor combination that I + + align:start position:0% +resistor capacitor combination that I + + + align:start position:0% +resistor capacitor combination that I +mentioned and what I'd like to do is + + align:start position:0% +mentioned and what I'd like to do is + + + align:start position:0% +mentioned and what I'd like to do is +look back at the oscilloscope trace and + + align:start position:0% +look back at the oscilloscope trace and + + + align:start position:0% +look back at the oscilloscope trace and +recall that the settling time with one + + align:start position:0% +recall that the settling time with one + + + align:start position:0% +recall that the settling time with one +over s compensation is about or is in + + align:start position:0% +over s compensation is about or is in + + + align:start position:0% +over s compensation is about or is in +excess of 100 microseconds and now let's + + align:start position:0% +excess of 100 microseconds and now let's + + + align:start position:0% +excess of 100 microseconds and now let's +go to the compensation that includes a + + align:start position:0% +go to the compensation that includes a + + + align:start position:0% +go to the compensation that includes a +zero I'll remove the single capacitor + + align:start position:0% +zero I'll remove the single capacitor + + + align:start position:0% +zero I'll remove the single capacitor +that was doing the compensation before + + align:start position:0% +that was doing the compensation before + + + align:start position:0% +that was doing the compensation before +and I'll put in the series RC connection + + align:start position:0% +and I'll put in the series RC connection + + + align:start position:0% +and I'll put in the series RC connection +and when we do that we notice a very + + align:start position:0% +and when we do that we notice a very + + + align:start position:0% +and when we do that we notice a very +dramatic improvement in performance + + align:start position:0% + + + + align:start position:0% + +we're now able to go to a much faster + + align:start position:0% +we're now able to go to a much faster + + + align:start position:0% +we're now able to go to a much faster +time scale and we notice for example + + align:start position:0% +time scale and we notice for example + + + align:start position:0% +time scale and we notice for example +that the trace has certainly virtually + + align:start position:0% +that the trace has certainly virtually + + + align:start position:0% +that the trace has certainly virtually +completely settled three or four + + align:start position:0% +completely settled three or four + + + align:start position:0% +completely settled three or four +divisions after the start of the + + align:start position:0% +divisions after the start of the + + + align:start position:0% +divisions after the start of the +transient we're two microseconds per + + align:start position:0% +transient we're two microseconds per + + + align:start position:0% +transient we're two microseconds per +division this time and consequently + + align:start position:0% +division this time and consequently + + + align:start position:0% +division this time and consequently +we're settling in in somewhere on the + + align:start position:0% +we're settling in in somewhere on the + + + align:start position:0% +we're settling in in somewhere on the +order of six to eight microseconds the + + align:start position:0% +order of six to eight microseconds the + + + align:start position:0% +order of six to eight microseconds the +basic transient is a very good one a + + align:start position:0% +basic transient is a very good one a + + + align:start position:0% +basic transient is a very good one a +very pleasant one the overshoot is oh I + + align:start position:0% +very pleasant one the overshoot is oh I + + + align:start position:0% +very pleasant one the overshoot is oh I +don't know 20 percent possibly of the + + align:start position:0% +don't know 20 percent possibly of the + + + align:start position:0% +don't know 20 percent possibly of the +amplitude of the step or something like + + align:start position:0% +amplitude of the step or something like + + + align:start position:0% +amplitude of the step or something like +that so we've very dramatically improved + + align:start position:0% +that so we've very dramatically improved + + + align:start position:0% +that so we've very dramatically improved +the phase margin of the system is + + align:start position:0% +the phase margin of the system is + + + align:start position:0% +the phase margin of the system is +evidenced at least by its step response + + align:start position:0% +evidenced at least by its step response + + + align:start position:0% +evidenced at least by its step response +but there's one bad thing remaining we + + align:start position:0% +but there's one bad thing remaining we + + + align:start position:0% +but there's one bad thing remaining we +notice that there's a series of little + + align:start position:0% +notice that there's a series of little + + + align:start position:0% +notice that there's a series of little +teeth on the trailing edge of the + + align:start position:0% +teeth on the trailing edge of the + + + align:start position:0% +teeth on the trailing edge of the +transient actually they exist on the + + align:start position:0% +transient actually they exist on the + + + align:start position:0% +transient actually they exist on the +leading edge too if you look at it + + align:start position:0% +leading edge too if you look at it + + + align:start position:0% +leading edge too if you look at it +carefully and so the the transient + + align:start position:0% +carefully and so the the transient + + + align:start position:0% +carefully and so the the transient +response of this setup or this + + align:start position:0% +response of this setup or this + + + align:start position:0% +response of this setup or this +configuration is almost + + align:start position:0% +configuration is almost + + + align:start position:0% +configuration is almost +right just doesn't quite make it and I'd + + align:start position:0% +right just doesn't quite make it and I'd + + + align:start position:0% +right just doesn't quite make it and I'd +like to think a little bit about why we + + align:start position:0% +like to think a little bit about why we + + + align:start position:0% +like to think a little bit about why we +might have that problem why do we get + + align:start position:0% +might have that problem why do we get + + + align:start position:0% +might have that problem why do we get +the teeth in this kind of compensation + + align:start position:0% +the teeth in this kind of compensation + + + align:start position:0% +the teeth in this kind of compensation +well what we're doing is using a network + + align:start position:0% +well what we're doing is using a network + + + align:start position:0% +well what we're doing is using a network +of the general type shown of course and + + align:start position:0% +of the general type shown of course and + + + align:start position:0% +of the general type shown of course and +the important part of this network is + + align:start position:0% +the important part of this network is + + + align:start position:0% +the important part of this network is +that at high frequencies or at least as + + align:start position:0% +that at high frequencies or at least as + + + align:start position:0% +that at high frequencies or at least as +far as the teeth are concerned at high + + align:start position:0% +far as the teeth are concerned at high + + + align:start position:0% +far as the teeth are concerned at high +frequencies this network looks resistive + + align:start position:0% +frequencies this network looks resistive + + + align:start position:0% +frequencies this network looks resistive +in contrast to either of the two other + + align:start position:0% +in contrast to either of the two other + + + align:start position:0% +in contrast to either of the two other +kinds of compensating networks we've + + align:start position:0% +kinds of compensating networks we've + + + align:start position:0% +kinds of compensating networks we've +looked at either the single capacitor or + + align:start position:0% +looked at either the single capacitor or + + + align:start position:0% +looked at either the single capacitor or +the t network that had two capacitors + + align:start position:0% +the t network that had two capacitors + + + align:start position:0% +the t network that had two capacitors +across the top of the T both of those + + align:start position:0% +across the top of the T both of those + + + align:start position:0% +across the top of the T both of those +networks look capacitive at high + + align:start position:0% +networks look capacitive at high + + + align:start position:0% +networks look capacitive at high +frequencies this one looks resistive + + align:start position:0% +frequencies this one looks resistive + + + align:start position:0% +frequencies this one looks resistive +between the terminals in other words + + align:start position:0% +between the terminals in other words + + + align:start position:0% +between the terminals in other words +when we use this for compensation around + + align:start position:0% +when we use this for compensation around + + + align:start position:0% +when we use this for compensation around +the second stage that local feedback + + align:start position:0% +the second stage that local feedback + + + align:start position:0% +the second stage that local feedback +path the minor loop feedback path looks + + align:start position:0% +path the minor loop feedback path looks + + + align:start position:0% +path the minor loop feedback path looks +resistive at high frequencies let's see + + align:start position:0% +resistive at high frequencies let's see + + + align:start position:0% +resistive at high frequencies let's see +what that does + + align:start position:0% + + + + align:start position:0% + +here I've showed a simplified model for + + align:start position:0% +here I've showed a simplified model for + + + align:start position:0% +here I've showed a simplified model for +the second stage of our operational + + align:start position:0% +the second stage of our operational + + + align:start position:0% +the second stage of our operational +amplifier the input of the second stage + + align:start position:0% +amplifier the input of the second stage + + + align:start position:0% +amplifier the input of the second stage +which if you recall is driven by a + + align:start position:0% +which if you recall is driven by a + + + align:start position:0% +which if you recall is driven by a +differential first stage in the + + align:start position:0% +differential first stage in the + + + align:start position:0% +differential first stage in the +operational amplifier generally looks + + align:start position:0% +operational amplifier generally looks + + + align:start position:0% +operational amplifier generally looks +like a parallel combination of an input + + align:start position:0% +like a parallel combination of an input + + + align:start position:0% +like a parallel combination of an input +resistance and an input capacitance and + + align:start position:0% +resistance and an input capacitance and + + + align:start position:0% +resistance and an input capacitance and +then we have a generator that gives us + + align:start position:0% +then we have a generator that gives us + + + align:start position:0% +then we have a generator that gives us +an output voltage from the second stage + + align:start position:0% +an output voltage from the second stage + + + align:start position:0% +an output voltage from the second stage +proportional to the voltage at the input + + align:start position:0% +proportional to the voltage at the input + + + align:start position:0% +proportional to the voltage at the input +to the second stage but there's also + + align:start position:0% +to the second stage but there's also + + + align:start position:0% +to the second stage but there's also +typically a single pole associated with + + align:start position:0% +typically a single pole associated with + + + align:start position:0% +typically a single pole associated with +that transfer function + + align:start position:0% +that transfer function + + + align:start position:0% +that transfer function +the physical reason for this pole is + + align:start position:0% +the physical reason for this pole is + + + align:start position:0% +the physical reason for this pole is +normally capacitive loading or at least + + align:start position:0% +normally capacitive loading or at least + + + align:start position:0% +normally capacitive loading or at least +one possibility is capacitive loading at + + align:start position:0% +one possibility is capacitive loading at + + + align:start position:0% +one possibility is capacitive loading at +the output of the second stage itself + + align:start position:0% +the output of the second stage itself + + + align:start position:0% +the output of the second stage itself +not at the output of the overall + + align:start position:0% +not at the output of the overall + + + align:start position:0% +not at the output of the overall +operational amplifier but rather at the + + align:start position:0% +operational amplifier but rather at the + + + align:start position:0% +operational amplifier but rather at the +output of the second stage itself and so + + align:start position:0% +output of the second stage itself and so + + + align:start position:0% +output of the second stage itself and so +that gives us a pole and now we put a + + align:start position:0% +that gives us a pole and now we put a + + + align:start position:0% +that gives us a pole and now we put a +minor loop from the output of the second + + align:start position:0% +minor loop from the output of the second + + + align:start position:0% +minor loop from the output of the second +stage back to its input well if at + + align:start position:0% +stage back to its input well if at + + + align:start position:0% +stage back to its input well if at +crossover in the minor loop this network + + align:start position:0% +crossover in the minor loop this network + + + align:start position:0% +crossover in the minor loop this network +looks principally capacitive from here + + align:start position:0% +looks principally capacitive from here + + + align:start position:0% +looks principally capacitive from here +to here in other words if it looks like + + align:start position:0% +to here in other words if it looks like + + + align:start position:0% +to here in other words if it looks like +a single capacitor or if it looks like a + + align:start position:0% +a single capacitor or if it looks like a + + + align:start position:0% +a single capacitor or if it looks like a +tea that has two capacitors across the + + align:start position:0% +tea that has two capacitors across the + + + align:start position:0% +tea that has two capacitors across the +top and a single resistor down on the + + align:start position:0% +top and a single resistor down on the + + + align:start position:0% +top and a single resistor down on the +the vertical portion of the tea then at + + align:start position:0% +the vertical portion of the tea then at + + + align:start position:0% +the vertical portion of the tea then at +high frequencies we get simply an + + align:start position:0% +high frequencies we get simply an + + + align:start position:0% +high frequencies we get simply an +attenuation between this voltage and + + align:start position:0% +attenuation between this voltage and + + + align:start position:0% +attenuation between this voltage and +this one we basically have a capacitive + + align:start position:0% +this one we basically have a capacitive + + + align:start position:0% +this one we basically have a capacitive +divider at high frequencies that + + align:start position:0% +divider at high frequencies that + + + align:start position:0% +divider at high frequencies that +involves the effective capacitance from + + align:start position:0% +involves the effective capacitance from + + + align:start position:0% +involves the effective capacitance from +this point to this point in the + + align:start position:0% +this point to this point in the + + + align:start position:0% +this point to this point in the +compensating Network working with the + + align:start position:0% +compensating Network working with the + + + align:start position:0% +compensating Network working with the +input capacitance to the second stage so + + align:start position:0% +input capacitance to the second stage so + + + align:start position:0% +input capacitance to the second stage so +we get simply some fraction of the + + align:start position:0% +we get simply some fraction of the + + + align:start position:0% +we get simply some fraction of the +voltage at the output of the second + + align:start position:0% +voltage at the output of the second + + + align:start position:0% +voltage at the output of the second +stage applied back to its input that's + + align:start position:0% +stage applied back to its input that's + + + align:start position:0% +stage applied back to its input that's +fine if we look at the minor loop the + + align:start position:0% +fine if we look at the minor loop the + + + align:start position:0% +fine if we look at the minor loop the +minor loop is quite well behaved under + + align:start position:0% +minor loop is quite well behaved under + + + align:start position:0% +minor loop is quite well behaved under +those conditions because we have + + align:start position:0% +those conditions because we have + + + align:start position:0% +those conditions because we have +effectively a single pole roll-off this + + align:start position:0% +effectively a single pole roll-off this + + + align:start position:0% +effectively a single pole roll-off this +pole in the minor loop in the vicinity + + align:start position:0% +pole in the minor loop in the vicinity + + + align:start position:0% +pole in the minor loop in the vicinity +of the minor loop crossover however + + align:start position:0% +of the minor loop crossover however + + + align:start position:0% +of the minor loop crossover however +consider what happens if at the + + align:start position:0% +consider what happens if at the + + + align:start position:0% +consider what happens if at the +crossover frequency of the minor loop + + align:start position:0% +crossover frequency of the minor loop + + + align:start position:0% +crossover frequency of the minor loop +this network looks basically resistive + + align:start position:0% +this network looks basically resistive + + + align:start position:0% +this network looks basically resistive +if it looks effectively like a resistor + + align:start position:0% +if it looks effectively like a resistor + + + align:start position:0% +if it looks effectively like a resistor +between here and here then it's entirely + + align:start position:0% +between here and here then it's entirely + + + align:start position:0% +between here and here then it's entirely +possible that we get an additional pole + + align:start position:0% +possible that we get an additional pole + + + align:start position:0% +possible that we get an additional pole +in the Meyer loop transponder leuk leuk + + align:start position:0% +in the Meyer loop transponder leuk leuk + + + align:start position:0% +in the Meyer loop transponder leuk leuk +transmission that reflects the loading + + align:start position:0% +transmission that reflects the loading + + + align:start position:0% +transmission that reflects the loading +of the input capacitance of the second + + align:start position:0% +of the input capacitance of the second + + + align:start position:0% +of the input capacitance of the second +stage working on that resistance we'd + + align:start position:0% +stage working on that resistance we'd + + + align:start position:0% +stage working on that resistance we'd +simply get an RC transfer function from + + align:start position:0% +simply get an RC transfer function from + + + align:start position:0% +simply get an RC transfer function from +here to here we combine that with one + + align:start position:0% +here to here we combine that with one + + + align:start position:0% +here to here we combine that with one +additional pole in the open-loop + + align:start position:0% +additional pole in the open-loop + + + align:start position:0% +additional pole in the open-loop +transfer function of the second stage + + align:start position:0% +transfer function of the second stage + + + align:start position:0% +transfer function of the second stage +and we find out that that we end up with + + align:start position:0% +and we find out that that we end up with + + + align:start position:0% +and we find out that that we end up with +a two pole roll-off if that two pole + + align:start position:0% +a two pole roll-off if that two pole + + + align:start position:0% +a two pole roll-off if that two pole +roll-off occurs or is in in progress in + + align:start position:0% +roll-off occurs or is in in progress in + + + align:start position:0% +roll-off occurs or is in in progress in +the vicinity of the monitor loop + + align:start position:0% +the vicinity of the monitor loop + + + align:start position:0% +the vicinity of the monitor loop +crossover why we can have very low phase + + align:start position:0% +crossover why we can have very low phase + + + align:start position:0% +crossover why we can have very low phase +margin in the minor loop and I think + + align:start position:0% +margin in the minor loop and I think + + + align:start position:0% +margin in the minor loop and I think +that's what gives us the T that we see + + align:start position:0% +that's what gives us the T that we see + + + align:start position:0% +that's what gives us the T that we see +in the transient response I think that's + + align:start position:0% +in the transient response I think that's + + + align:start position:0% +in the transient response I think that's +sign of impending minor loop instability + + align:start position:0% +sign of impending minor loop instability + + + align:start position:0% +sign of impending minor loop instability +I think that what's happening is that if + + align:start position:0% +I think that what's happening is that if + + + align:start position:0% +I think that what's happening is that if +we could physically reach into the + + align:start position:0% +we could physically reach into the + + + align:start position:0% +we could physically reach into the +amplifier and look at the actual output + + align:start position:0% +amplifier and look at the actual output + + + align:start position:0% +amplifier and look at the actual output +of the second stage it'd be isolating + + align:start position:0% +of the second stage it'd be isolating + + + align:start position:0% +of the second stage it'd be isolating +quite violently an awful lot of + + align:start position:0% +quite violently an awful lot of + + + align:start position:0% +quite violently an awful lot of +overshoot and so forth we see some + + align:start position:0% +overshoot and so forth we see some + + + align:start position:0% +overshoot and so forth we see some +remain of that because we're looking at + + align:start position:0% +remain of that because we're looking at + + + align:start position:0% +remain of that because we're looking at +this through a low pass filter we go + + align:start position:0% +this through a low pass filter we go + + + align:start position:0% +this through a low pass filter we go +ahead and remember we have a tenth of a + + align:start position:0% +ahead and remember we have a tenth of a + + + align:start position:0% +ahead and remember we have a tenth of a +micro farad capacity of the Ring + + align:start position:0% +micro farad capacity of the Ring + + + align:start position:0% +micro farad capacity of the Ring +frequency at present is several + + align:start position:0% +frequency at present is several + + + align:start position:0% +frequency at present is several +megahertz were at at two microseconds + + align:start position:0% +megahertz were at at two microseconds + + + align:start position:0% +megahertz were at at two microseconds +per division the frequency of the teeth + + align:start position:0% +per division the frequency of the teeth + + + align:start position:0% +per division the frequency of the teeth +is is several megahertz and we're + + align:start position:0% +is is several megahertz and we're + + + align:start position:0% +is is several megahertz and we're +looking at that through a very low pass + + align:start position:0% +looking at that through a very low pass + + + align:start position:0% +looking at that through a very low pass +filter because of the output resistance + + align:start position:0% +filter because of the output resistance + + + align:start position:0% +filter because of the output resistance +of the operational amplifier and and the + + align:start position:0% +of the operational amplifier and and the + + + align:start position:0% +of the operational amplifier and and the +tenth micro farad capacitor flowed that + + align:start position:0% +tenth micro farad capacitor flowed that + + + align:start position:0% +tenth micro farad capacitor flowed that +we've seen and so we see just a little + + align:start position:0% +we've seen and so we see just a little + + + align:start position:0% +we've seen and so we see just a little +remnant of this large oscillation that's + + align:start position:0% +remnant of this large oscillation that's + + + align:start position:0% +remnant of this large oscillation that's +occurring at the actual output of the + + align:start position:0% +occurring at the actual output of the + + + align:start position:0% +occurring at the actual output of the +second stage before the final buffer + + align:start position:0% +second stage before the final buffer + + + align:start position:0% +second stage before the final buffer +amplifier associated with the op-amp and + + align:start position:0% +amplifier associated with the op-amp and + + + align:start position:0% +amplifier associated with the op-amp and +there's some non-linearity to some + + align:start position:0% +there's some non-linearity to some + + + align:start position:0% +there's some non-linearity to some +crossover problems and so forth but I + + align:start position:0% +crossover problems and so forth but I + + + align:start position:0% +crossover problems and so forth but I +believe that the teeth reflect an + + align:start position:0% +believe that the teeth reflect an + + + align:start position:0% +believe that the teeth reflect an +impending minor loop instability the way + + align:start position:0% +impending minor loop instability the way + + + align:start position:0% +impending minor loop instability the way +to get around that the way to improve + + align:start position:0% +to get around that the way to improve + + + align:start position:0% +to get around that the way to improve +the situation is to consider what would + + align:start position:0% +the situation is to consider what would + + + align:start position:0% +the situation is to consider what would +happen if we added one more capacitor + + align:start position:0% +happen if we added one more capacitor + + + align:start position:0% +happen if we added one more capacitor +here now what we'd like to do is + + align:start position:0% +here now what we'd like to do is + + + align:start position:0% +here now what we'd like to do is +maintain the general feature associated + + align:start position:0% +maintain the general feature associated + + + align:start position:0% +maintain the general feature associated +with the transfer function we had + + align:start position:0% +with the transfer function we had + + + align:start position:0% +with the transfer function we had +mentioned earlier and what that + + align:start position:0% +mentioned earlier and what that + + + align:start position:0% +mentioned earlier and what that +means is that this capacitor must be + + align:start position:0% +means is that this capacitor must be + + + align:start position:0% +means is that this capacitor must be +much smaller than our original capacitor + + align:start position:0% +much smaller than our original capacitor + + + align:start position:0% +much smaller than our original capacitor +so we might call this some big capacitor + + align:start position:0% +so we might call this some big capacitor + + + align:start position:0% +so we might call this some big capacitor +and this some small or s is probably a + + align:start position:0% +and this some small or s is probably a + + + align:start position:0% +and this some small or s is probably a +poor choice see little and the ratio + + align:start position:0% +poor choice see little and the ratio + + + align:start position:0% +poor choice see little and the ratio +between C big and C little should be + + align:start position:0% +between C big and C little should be + + + align:start position:0% +between C big and C little should be +quite great the reason being that when + + align:start position:0% +quite great the reason being that when + + + align:start position:0% +quite great the reason being that when +we add C little the effect on the ideal + + align:start position:0% +we add C little the effect on the ideal + + + align:start position:0% +we add C little the effect on the ideal +open-loop transfer function of the + + align:start position:0% +open-loop transfer function of the + + + align:start position:0% +open-loop transfer function of the +operational amplifier is to add an + + align:start position:0% +operational amplifier is to add an + + + align:start position:0% +operational amplifier is to add an +additional pole maybe out here we'd like + + align:start position:0% +additional pole maybe out here we'd like + + + align:start position:0% +additional pole maybe out here we'd like +to make sure that that pole occurs well + + align:start position:0% +to make sure that that pole occurs well + + + align:start position:0% +to make sure that that pole occurs well +after crossover in the overall loop so + + align:start position:0% +after crossover in the overall loop so + + + align:start position:0% +after crossover in the overall loop so +that we don't compromise the stability + + align:start position:0% +that we don't compromise the stability + + + align:start position:0% +that we don't compromise the stability +of the overall loop we only want to use + + align:start position:0% +of the overall loop we only want to use + + + align:start position:0% +of the overall loop we only want to use +this capacitor to improve the stability + + align:start position:0% +this capacitor to improve the stability + + + align:start position:0% +this capacitor to improve the stability +of the minor loop and in this particular + + align:start position:0% +of the minor loop and in this particular + + + align:start position:0% +of the minor loop and in this particular +setup we've chosen our small capacitor + + align:start position:0% +setup we've chosen our small capacitor + + + align:start position:0% +setup we've chosen our small capacitor +here to be roughly 1/10 of the value of + + align:start position:0% +here to be roughly 1/10 of the value of + + + align:start position:0% +here to be roughly 1/10 of the value of +the big capacitor and that results in a + + align:start position:0% +the big capacitor and that results in a + + + align:start position:0% +the big capacitor and that results in a +very good compromise between maintaining + + align:start position:0% +very good compromise between maintaining + + + align:start position:0% +very good compromise between maintaining +stability in the minor loop and yet not + + align:start position:0% +stability in the minor loop and yet not + + + align:start position:0% +stability in the minor loop and yet not +compromising the stability of the + + align:start position:0% +compromising the stability of the + + + align:start position:0% +compromising the stability of the +overall loop so let's now add that + + align:start position:0% +overall loop so let's now add that + + + align:start position:0% +overall loop so let's now add that +capacitor when we do that we notice the + + align:start position:0% +capacitor when we do that we notice the + + + align:start position:0% +capacitor when we do that we notice the +basic transient response remains the + + align:start position:0% +basic transient response remains the + + + align:start position:0% +basic transient response remains the +same + + align:start position:0% +same + + + align:start position:0% +same +we have about the 20% overshoot or there + + align:start position:0% +we have about the 20% overshoot or there + + + align:start position:0% +we have about the 20% overshoot or there +abouts but the teeth have completely + + align:start position:0% +abouts but the teeth have completely + + + align:start position:0% +abouts but the teeth have completely +gone away we've we've eliminated the + + align:start position:0% +gone away we've we've eliminated the + + + align:start position:0% +gone away we've we've eliminated the +minor loop problem by making the + + align:start position:0% +minor loop problem by making the + + + align:start position:0% +minor loop problem by making the +compensating Network look capacitive at + + align:start position:0% +compensating Network look capacitive at + + + align:start position:0% +compensating Network look capacitive at +the crossover frequency of the minor + + align:start position:0% +the crossover frequency of the minor + + + align:start position:0% +the crossover frequency of the minor +loop that frequency of course is much + + align:start position:0% +loop that frequency of course is much + + + align:start position:0% +loop that frequency of course is much +higher than the overall crossover + + align:start position:0% +higher than the overall crossover + + + align:start position:0% +higher than the overall crossover +frequency let's doing once more let's + + align:start position:0% +frequency let's doing once more let's + + + align:start position:0% +frequency let's doing once more let's +take out that capacitor the teeth come + + align:start position:0% +take out that capacitor the teeth come + + + align:start position:0% +take out that capacitor the teeth come +we add the capacitor back in simply move + + align:start position:0% +we add the capacitor back in simply move + + + align:start position:0% +we add the capacitor back in simply move +this lead over the minor loop whoops + + align:start position:0% + + + + align:start position:0% + +well + + align:start position:0% + + + + align:start position:0% + +it's really a matter of placement the + + align:start position:0% +it's really a matter of placement the + + + align:start position:0% +it's really a matter of placement the +minor loop gets much better behaved and + + align:start position:0% +minor loop gets much better behaved and + + + align:start position:0% +minor loop gets much better behaved and +we really haven't significantly changed + + align:start position:0% +we really haven't significantly changed + + + align:start position:0% +we really haven't significantly changed +the overall features we haven't changed + + align:start position:0% +the overall features we haven't changed + + + align:start position:0% +the overall features we haven't changed +things significantly in the vicinity of + + align:start position:0% +things significantly in the vicinity of + + + align:start position:0% +things significantly in the vicinity of +the major loop crossover what's the + + align:start position:0% +the major loop crossover what's the + + + align:start position:0% +the major loop crossover what's the +difficulty with this kind of + + align:start position:0% +difficulty with this kind of + + + align:start position:0% +difficulty with this kind of +compensation well one of the things is + + align:start position:0% +compensation well one of the things is + + + align:start position:0% +compensation well one of the things is +it's very very special purpose we have + + align:start position:0% +it's very very special purpose we have + + + align:start position:0% +it's very very special purpose we have +already looked at one over s squared + + align:start position:0% +already looked at one over s squared + + + align:start position:0% +already looked at one over s squared +compensation and found out that it was + + align:start position:0% +compensation and found out that it was + + + align:start position:0% +compensation and found out that it was +somewhat special purpose here we're + + align:start position:0% +somewhat special purpose here we're + + + align:start position:0% +somewhat special purpose here we're +tailoring compensation to a specific + + align:start position:0% +tailoring compensation to a specific + + + align:start position:0% +tailoring compensation to a specific +load in particular a capacitive load and + + align:start position:0% +load in particular a capacitive load and + + + align:start position:0% +load in particular a capacitive load and +we're choosing the zero associated with + + align:start position:0% +we're choosing the zero associated with + + + align:start position:0% +we're choosing the zero associated with +this form of compensation to bear some + + align:start position:0% +this form of compensation to bear some + + + align:start position:0% +this form of compensation to bear some +relationship to the pole caused by the + + align:start position:0% +relationship to the pole caused by the + + + align:start position:0% +relationship to the pole caused by the +capacitive load what happens if we take + + align:start position:0% +capacitive load what happens if we take + + + align:start position:0% +capacitive load what happens if we take +the capacitive load away well the system + + align:start position:0% +the capacitive load away well the system + + + align:start position:0% +the capacitive load away well the system +goes unstable we can see that let me go + + align:start position:0% +goes unstable we can see that let me go + + + align:start position:0% +goes unstable we can see that let me go +back to zero capacitive load and we + + align:start position:0% +back to zero capacitive load and we + + + align:start position:0% +back to zero capacitive load and we +notice even if we eliminate the input Y + + align:start position:0% +notice even if we eliminate the input Y + + + align:start position:0% +notice even if we eliminate the input Y +the amplifier is oscillating + + align:start position:0% +the amplifier is oscillating + + + align:start position:0% +the amplifier is oscillating +I'm sure whether we can sync on that or + + align:start position:0% +I'm sure whether we can sync on that or + + + align:start position:0% +I'm sure whether we can sync on that or +not sure here the amplifier is + + align:start position:0% +not sure here the amplifier is + + + align:start position:0% +not sure here the amplifier is +oscillating at quite a high frequency + + align:start position:0% +oscillating at quite a high frequency + + + align:start position:0% +oscillating at quite a high frequency +several megahertz reflecting the fact + + align:start position:0% +several megahertz reflecting the fact + + + align:start position:0% +several megahertz reflecting the fact +that we've taken away the capacitive + + align:start position:0% +that we've taken away the capacitive + + + align:start position:0% +that we've taken away the capacitive +load which in Canessa Cerie for + + align:start position:0% +load which in Canessa Cerie for + + + align:start position:0% +load which in Canessa Cerie for +stabilization when we use this sort of + + align:start position:0% +stabilization when we use this sort of + + + align:start position:0% +stabilization when we use this sort of +compensation let's put the capacitive + + align:start position:0% +compensation let's put the capacitive + + + align:start position:0% +compensation let's put the capacitive +load back on that the amplifier is now + + align:start position:0% +load back on that the amplifier is now + + + align:start position:0% +load back on that the amplifier is now +well-behaved and we can + + align:start position:0% + + + + align:start position:0% + +get our well damped response back the + + align:start position:0% +get our well damped response back the + + + align:start position:0% +get our well damped response back the +amplifier will oscillate even if we load + + align:start position:0% +amplifier will oscillate even if we load + + + align:start position:0% +amplifier will oscillate even if we load +it with a capacitor other than the + + align:start position:0% +it with a capacitor other than the + + + align:start position:0% +it with a capacitor other than the +intended one if we go to the O one micro + + align:start position:0% +intended one if we go to the O one micro + + + align:start position:0% +intended one if we go to the O one micro +farad capacitor load once again the + + align:start position:0% +farad capacitor load once again the + + + align:start position:0% +farad capacitor load once again the +amplifier is oscillating presumably at a + + align:start position:0% +amplifier is oscillating presumably at a + + + align:start position:0% +amplifier is oscillating presumably at a +different frequency + + align:start position:0% +different frequency + + + align:start position:0% +different frequency +but once again oscillating so if we go + + align:start position:0% +but once again oscillating so if we go + + + align:start position:0% +but once again oscillating so if we go +back to the capacitive load we designed + + align:start position:0% +back to the capacitive load we designed + + + align:start position:0% +back to the capacitive load we designed +the compensation for things are fine but + + align:start position:0% +the compensation for things are fine but + + + align:start position:0% +the compensation for things are fine but +if we change the magnitude of that + + align:start position:0% +if we change the magnitude of that + + + align:start position:0% +if we change the magnitude of that +capacitive load or if we eliminate it + + align:start position:0% +capacitive load or if we eliminate it + + + align:start position:0% +capacitive load or if we eliminate it +entirely things get much worse so that's + + align:start position:0% +entirely things get much worse so that's + + + align:start position:0% +entirely things get much worse so that's +one of the problems with this form of + + align:start position:0% +one of the problems with this form of + + + align:start position:0% +one of the problems with this form of +compensation I'd like to look at one + + align:start position:0% +compensation I'd like to look at one + + + align:start position:0% +compensation I'd like to look at one +final form of compensation we found out + + align:start position:0% +final form of compensation we found out + + + align:start position:0% +final form of compensation we found out +that one way to offset the effects of an + + align:start position:0% +that one way to offset the effects of an + + + align:start position:0% +that one way to offset the effects of an +additional pole in the loop is to add a + + align:start position:0% +additional pole in the loop is to add a + + + align:start position:0% +additional pole in the loop is to add a +zero that's what we were doing here but + + align:start position:0% +zero that's what we were doing here but + + + align:start position:0% +zero that's what we were doing here but +now let me pose a different problem + + align:start position:0% +now let me pose a different problem + + + align:start position:0% +now let me pose a different problem +suppose we anticipate an additional pole + + align:start position:0% +suppose we anticipate an additional pole + + + align:start position:0% +suppose we anticipate an additional pole +in our loop transmission but we don't + + align:start position:0% +in our loop transmission but we don't + + + align:start position:0% +in our loop transmission but we don't +know the frequency at which that pole + + align:start position:0% +know the frequency at which that pole + + + align:start position:0% +know the frequency at which that pole +will be located so what we're looking + + align:start position:0% +will be located so what we're looking + + + align:start position:0% +will be located so what we're looking +here for now is really compensation for + + align:start position:0% +here for now is really compensation for + + + align:start position:0% +here for now is really compensation for +those who don't know what they're doing + + align:start position:0% +those who don't know what they're doing + + + align:start position:0% +those who don't know what they're doing +possibly or something where we have a + + align:start position:0% +possibly or something where we have a + + + align:start position:0% +possibly or something where we have a +system that has certain uncertain + + align:start position:0% +system that has certain uncertain + + + align:start position:0% +system that has certain uncertain +parameters some uncertain parameters how + + align:start position:0% +parameters some uncertain parameters how + + + align:start position:0% +parameters some uncertain parameters how +might we compensate in that case it's + + align:start position:0% +might we compensate in that case it's + + + align:start position:0% +might we compensate in that case it's +not but this is a more than academic + + align:start position:0% +not but this is a more than academic + + + align:start position:0% +not but this is a more than academic +interest there are certain elements + + align:start position:0% +interest there are certain elements + + + align:start position:0% +interest there are certain elements +which in fact have dynamics that vary as + + align:start position:0% +which in fact have dynamics that vary as + + + align:start position:0% +which in fact have dynamics that vary as +a function of conditions for example a + + align:start position:0% +a function of conditions for example a + + + align:start position:0% +a function of conditions for example a +very simple example is that of a power + + align:start position:0% +very simple example is that of a power + + + align:start position:0% +very simple example is that of a power +supply again if you build a power supply + + align:start position:0% +supply again if you build a power supply + + + align:start position:0% +supply again if you build a power supply +into some system why people go ahead and + + align:start position:0% +into some system why people go ahead and + + + align:start position:0% +into some system why people go ahead and +connect loads to the power supply very + + align:start position:0% +connect loads to the power supply very + + + align:start position:0% +connect loads to the power supply very +frequently those loads include their own + + align:start position:0% +frequently those loads include their own + + + align:start position:0% +frequently those loads include their own +decoupling capacitors consequently you + + align:start position:0% +decoupling capacitors consequently you + + + align:start position:0% +decoupling capacitors consequently you +can add a great deal of capacitance to + + align:start position:0% +can add a great deal of capacitance to + + + align:start position:0% +can add a great deal of capacitance to +the output of the power supply you don't + + align:start position:0% +the output of the power supply you don't + + + align:start position:0% +the output of the power supply you don't +necessarily know the exact amount you + + align:start position:0% +necessarily know the exact amount you + + + align:start position:0% +necessarily know the exact amount you +can bound put a lower bound on it by by + + align:start position:0% +can bound put a lower bound on it by by + + + align:start position:0% +can bound put a lower bound on it by by +including some capacitance internally + + align:start position:0% +including some capacitance internally + + + align:start position:0% +including some capacitance internally +but you're never sure what the total + + align:start position:0% +but you're never sure what the total + + + align:start position:0% +but you're never sure what the total +amount + + align:start position:0% +amount + + + align:start position:0% +amount +capacitance how large the load capacitor + + align:start position:0% +capacitance how large the load capacitor + + + align:start position:0% +capacitance how large the load capacitor +can be there's another possibility + + align:start position:0% +can be there's another possibility + + + align:start position:0% +can be there's another possibility +there's an element that's quite + + align:start position:0% +there's an element that's quite + + + align:start position:0% +there's an element that's quite +frequently used as a gain control + + align:start position:0% +frequently used as a gain control + + + align:start position:0% +frequently used as a gain control +element that consists of a photo + + align:start position:0% +element that consists of a photo + + + align:start position:0% +element that consists of a photo +resistor illuminated by a lamp and by + + align:start position:0% +resistor illuminated by a lamp and by + + + align:start position:0% +resistor illuminated by a lamp and by +changing the illumination you change the + + align:start position:0% +changing the illumination you change the + + + align:start position:0% +changing the illumination you change the +value of the resistor you're able to use + + align:start position:0% +value of the resistor you're able to use + + + align:start position:0% +value of the resistor you're able to use +that as some sort of a gain control + + align:start position:0% +that as some sort of a gain control + + + align:start position:0% +that as some sort of a gain control +mechanism build a feedback loop that + + align:start position:0% +mechanism build a feedback loop that + + + align:start position:0% +mechanism build a feedback loop that +adjusts lamp intensity in order to get a + + align:start position:0% +adjusts lamp intensity in order to get a + + + align:start position:0% +adjusts lamp intensity in order to get a +desired signal level out of an overall + + align:start position:0% +desired signal level out of an overall + + + align:start position:0% +desired signal level out of an overall +system for example well the nature of + + align:start position:0% +system for example well the nature of + + + align:start position:0% +system for example well the nature of +the photo resistors used in those + + align:start position:0% +the photo resistors used in those + + + align:start position:0% +the photo resistors used in those +devices is such that as you change + + align:start position:0% +devices is such that as you change + + + align:start position:0% +devices is such that as you change +illumination the time constant the pole + + align:start position:0% +illumination the time constant the pole + + + align:start position:0% +illumination the time constant the pole +associated with that transfer function + + align:start position:0% +associated with that transfer function + + + align:start position:0% +associated with that transfer function +the transfer function relating light to + + align:start position:0% +the transfer function relating light to + + + align:start position:0% +the transfer function relating light to +resistance value changes that the time + + align:start position:0% +resistance value changes that the time + + + align:start position:0% +resistance value changes that the time +constant is actually lower at low + + align:start position:0% +constant is actually lower at low + + + align:start position:0% +constant is actually lower at low +illumination levels than it is at high + + align:start position:0% +illumination levels than it is at high + + + align:start position:0% +illumination levels than it is at high +lumen illumination levels another + + align:start position:0% +lumen illumination levels another + + + align:start position:0% +lumen illumination levels another +problem exists in that kind of a loop in + + align:start position:0% +problem exists in that kind of a loop in + + + align:start position:0% +problem exists in that kind of a loop in +that the gain the loop transmission in + + align:start position:0% +that the gain the loop transmission in + + + align:start position:0% +that the gain the loop transmission in +these sort of gain control loops is + + align:start position:0% +these sort of gain control loops is + + + align:start position:0% +these sort of gain control loops is +always a function of operating + + align:start position:0% +always a function of operating + + + align:start position:0% +always a function of operating +conditions it's a function of the amount + + align:start position:0% +conditions it's a function of the amount + + + align:start position:0% +conditions it's a function of the amount +of gain control that's that's present at + + align:start position:0% +of gain control that's that's present at + + + align:start position:0% +of gain control that's that's present at +a given moment and so here you have a + + align:start position:0% +a given moment and so here you have a + + + align:start position:0% +a given moment and so here you have a +loop that has to on certain variables + + align:start position:0% +loop that has to on certain variables + + + align:start position:0% +loop that has to on certain variables +one the location of a pole another one + + align:start position:0% +one the location of a pole another one + + + align:start position:0% +one the location of a pole another one +being the loop transmission magnitude + + align:start position:0% +being the loop transmission magnitude + + + align:start position:0% +being the loop transmission magnitude +and what I'd like to look at now is a + + align:start position:0% +and what I'd like to look at now is a + + + align:start position:0% +and what I'd like to look at now is a +fourth and final form of compensation + + align:start position:0% +fourth and final form of compensation + + + align:start position:0% +fourth and final form of compensation +that will allow us to maintain a good + + align:start position:0% +that will allow us to maintain a good + + + align:start position:0% +that will allow us to maintain a good +degree of stability in view of these + + align:start position:0% +degree of stability in view of these + + + align:start position:0% +degree of stability in view of these +sorts of uncertain parameters the the + + align:start position:0% +sorts of uncertain parameters the the + + + align:start position:0% +sorts of uncertain parameters the the +test configuration that we're going to + + align:start position:0% +test configuration that we're going to + + + align:start position:0% +test configuration that we're going to +look at is as follows + + align:start position:0% + + + + align:start position:0% + +here we build up a loop that allows us + + align:start position:0% +here we build up a loop that allows us + + + align:start position:0% +here we build up a loop that allows us +to very easily add a pole to the + + align:start position:0% +to very easily add a pole to the + + + align:start position:0% +to very easily add a pole to the +open-loop transfer function of the + + align:start position:0% +open-loop transfer function of the + + + align:start position:0% +open-loop transfer function of the +operational amplifier that's used and + + align:start position:0% +operational amplifier that's used and + + + align:start position:0% +operational amplifier that's used and +furthermore vary its location over a + + align:start position:0% +furthermore vary its location over a + + + align:start position:0% +furthermore vary its location over a +very wide range of frequencies here we + + align:start position:0% +very wide range of frequencies here we + + + align:start position:0% +very wide range of frequencies here we +have the operational amplifier that + + align:start position:0% +have the operational amplifier that + + + align:start position:0% +have the operational amplifier that +we're using with its compensating + + align:start position:0% +we're using with its compensating + + + align:start position:0% +we're using with its compensating +network at its output we add an R and C + + align:start position:0% +network at its output we add an R and C + + + align:start position:0% +network at its output we add an R and C +and we're able to adjust the values of + + align:start position:0% +and we're able to adjust the values of + + + align:start position:0% +and we're able to adjust the values of +the R and C change the values so that we + + align:start position:0% +the R and C change the values so that we + + + align:start position:0% +the R and C change the values so that we +can add an additional pole to the loop + + align:start position:0% +can add an additional pole to the loop + + + align:start position:0% +can add an additional pole to the loop +transmission at over a very wide range + + align:start position:0% +transmission at over a very wide range + + + align:start position:0% +transmission at over a very wide range +of frequencies by appropriately + + align:start position:0% +of frequencies by appropriately + + + align:start position:0% +of frequencies by appropriately +selecting the R 1 C 1 product we then + + align:start position:0% +selecting the R 1 C 1 product we then + + + align:start position:0% +selecting the R 1 C 1 product we then +have a buffer amplifier a little unity + + align:start position:0% +have a buffer amplifier a little unity + + + align:start position:0% +have a buffer amplifier a little unity +gain follower that has a bandwidth much + + align:start position:0% +gain follower that has a bandwidth much + + + align:start position:0% +gain follower that has a bandwidth much +much greater than the actual operational + + align:start position:0% +much greater than the actual operational + + + align:start position:0% +much greater than the actual operational +amplifier we're using and we just use + + align:start position:0% +amplifier we're using and we just use + + + align:start position:0% +amplifier we're using and we just use +this to prevent any loading on the RC + + align:start position:0% +this to prevent any loading on the RC + + + align:start position:0% +this to prevent any loading on the RC +network a little resistor that's + + align:start position:0% +network a little resistor that's + + + align:start position:0% +network a little resistor that's +recommended by the manufacturer when one + + align:start position:0% +recommended by the manufacturer when one + + + align:start position:0% +recommended by the manufacturer when one +uses this amplifier and then we close + + align:start position:0% +uses this amplifier and then we close + + + align:start position:0% +uses this amplifier and then we close +the overall feedback loop so we have the + + align:start position:0% +the overall feedback loop so we have the + + + align:start position:0% +the overall feedback loop so we have the +dynamics of this amplifier is such that + + align:start position:0% +dynamics of this amplifier is such that + + + align:start position:0% +dynamics of this amplifier is such that +it's basically transparent consequently + + align:start position:0% +it's basically transparent consequently + + + align:start position:0% +it's basically transparent consequently +we have a loop transmission in this loop + + align:start position:0% +we have a loop transmission in this loop + + + align:start position:0% +we have a loop transmission in this loop +that's that of the operational amplifier + + align:start position:0% +that's that of the operational amplifier + + + align:start position:0% +that's that of the operational amplifier +times 1 over R 1 C 1 s plus 1 the + + align:start position:0% +times 1 over R 1 C 1 s plus 1 the + + + align:start position:0% +times 1 over R 1 C 1 s plus 1 the +low-pass characteristic of this network + + align:start position:0% +low-pass characteristic of this network + + + align:start position:0% +low-pass characteristic of this network +and say what we're going to do is + + align:start position:0% +and say what we're going to do is + + + align:start position:0% +and say what we're going to do is +attempt to come up with a compensation + + align:start position:0% +attempt to come up with a compensation + + + align:start position:0% +attempt to come up with a compensation +where we maintain adequate stability + + align:start position:0% +where we maintain adequate stability + + + align:start position:0% +where we maintain adequate stability +over a very wide range of R 1 C 1 + + align:start position:0% +over a very wide range of R 1 C 1 + + + align:start position:0% +over a very wide range of R 1 C 1 +products the difficulty of course is + + align:start position:0% +products the difficulty of course is + + + align:start position:0% +products the difficulty of course is +that if we use a single pole + + align:start position:0% +that if we use a single pole + + + align:start position:0% +that if we use a single pole +compensation with a fixed value of + + align:start position:0% +compensation with a fixed value of + + + align:start position:0% +compensation with a fixed value of +capacitor why certain values of the R 1 + + align:start position:0% +capacitor why certain values of the R 1 + + + align:start position:0% +capacitor why certain values of the R 1 +C 1 product will cause us to crossover + + align:start position:0% +C 1 product will cause us to crossover + + + align:start position:0% +C 1 product will cause us to crossover +in a 1 over s squared region in fact + + align:start position:0% +in a 1 over s squared region in fact + + + align:start position:0% +in a 1 over s squared region in fact +it's certainly possible to have very + + align:start position:0% +it's certainly possible to have very + + + align:start position:0% +it's certainly possible to have very +very long regions of 1 over s squared + + align:start position:0% +very long regions of 1 over s squared + + + align:start position:0% +very long regions of 1 over s squared +roll-off with appropriate choices of the + + align:start position:0% +roll-off with appropriate choices of the + + + align:start position:0% +roll-off with appropriate choices of the +R 1 C 1 product and so we can get very + + align:start position:0% +R 1 C 1 product and so we can get very + + + align:start position:0% +R 1 C 1 product and so we can get very +very low phase margins in that sort of a + + align:start position:0% +very low phase margins in that sort of a + + + align:start position:0% +very low phase margins in that sort of a +system if we choose compensation that + + align:start position:0% +system if we choose compensation that + + + align:start position:0% +system if we choose compensation that +includes a zero we're again in trouble + + align:start position:0% +includes a zero we're again in trouble + + + align:start position:0% +includes a zero we're again in trouble +because we saw in last demonstration + + align:start position:0% +because we saw in last demonstration + + + align:start position:0% +because we saw in last demonstration +that we have to tailor the location of a + + align:start position:0% +that we have to tailor the location of a + + + align:start position:0% +that we have to tailor the location of a +zero in that kind of compensation + + align:start position:0% +zero in that kind of compensation + + + align:start position:0% +zero in that kind of compensation +civically the load capacitance we're + + align:start position:0% +civically the load capacitance we're + + + align:start position:0% +civically the load capacitance we're +going to have and if we used it in this + + align:start position:0% +going to have and if we used it in this + + + align:start position:0% +going to have and if we used it in this +configuration why what we'd have to do + + align:start position:0% +configuration why what we'd have to do + + + align:start position:0% +configuration why what we'd have to do +is is tailor the zero location to the + + align:start position:0% +is is tailor the zero location to the + + + align:start position:0% +is is tailor the zero location to the +precise value of the r1 c1 product that + + align:start position:0% +precise value of the r1 c1 product that + + + align:start position:0% +precise value of the r1 c1 product that +used at least within a factor of two or + + align:start position:0% +used at least within a factor of two or + + + align:start position:0% +used at least within a factor of two or +three and if we state is one of the + + align:start position:0% +three and if we state is one of the + + + align:start position:0% +three and if we state is one of the +rules of the game or one of the + + align:start position:0% +rules of the game or one of the + + + align:start position:0% +rules of the game or one of the +uncertainties here that that the we + + align:start position:0% +uncertainties here that that the we + + + align:start position:0% +uncertainties here that that the we +don't know the r1 c1 product beforehand + + align:start position:0% +don't know the r1 c1 product beforehand + + + align:start position:0% +don't know the r1 c1 product beforehand +while we're not able to use that sort of + + align:start position:0% +while we're not able to use that sort of + + + align:start position:0% +while we're not able to use that sort of +compensation let me suggest another + + align:start position:0% +compensation let me suggest another + + + align:start position:0% +compensation let me suggest another +approach suppose we could come up with + + align:start position:0% +approach suppose we could come up with + + + align:start position:0% +approach suppose we could come up with +way of compensating the amplifier such + + align:start position:0% +way of compensating the amplifier such + + + align:start position:0% +way of compensating the amplifier such +that it's open loop transfer function + + align:start position:0% +that it's open loop transfer function + + + align:start position:0% +that it's open loop transfer function +rolled off proportional to 1 over the + + align:start position:0% +rolled off proportional to 1 over the + + + align:start position:0% +rolled off proportional to 1 over the +square root of s if we did that let's + + align:start position:0% +square root of s if we did that let's + + + align:start position:0% +square root of s if we did that let's +see what's the characteristics that are + + align:start position:0% +see what's the characteristics that are + + + align:start position:0% +see what's the characteristics that are +that's associated with a 1 over the + + align:start position:0% +that's associated with a 1 over the + + + align:start position:0% +that's associated with a 1 over the +square root of s roll off + + align:start position:0% +square root of s roll off + + + align:start position:0% +square root of s roll off +well the phase shift associated with the + + align:start position:0% +well the phase shift associated with the + + + align:start position:0% +well the phase shift associated with the +amplifier itself with its open-loop + + align:start position:0% +amplifier itself with its open-loop + + + align:start position:0% +amplifier itself with its open-loop +transfer function would always be minus + + align:start position:0% +transfer function would always be minus + + + align:start position:0% +transfer function would always be minus +45 degrees that's the angle associated + + align:start position:0% +45 degrees that's the angle associated + + + align:start position:0% +45 degrees that's the angle associated +with a 1 over radical S transfer + + align:start position:0% +with a 1 over radical S transfer + + + align:start position:0% +with a 1 over radical S transfer +function however the magnitude would + + align:start position:0% +function however the magnitude would + + + align:start position:0% +function however the magnitude would +drop off and and that means that if we + + align:start position:0% +drop off and and that means that if we + + + align:start position:0% +drop off and and that means that if we +designed our 1 over radical s amplifier + + align:start position:0% +designed our 1 over radical s amplifier + + + align:start position:0% +designed our 1 over radical s amplifier +properly we could arrange to have it go + + align:start position:0% +properly we could arrange to have it go + + + align:start position:0% +properly we could arrange to have it go +through unity gain at a sufficiently low + + align:start position:0% +through unity gain at a sufficiently low + + + align:start position:0% +through unity gain at a sufficiently low +frequency so that it would be stable + + align:start position:0% +frequency so that it would be stable + + + align:start position:0% +frequency so that it would be stable +without an additional pole added to its + + align:start position:0% +without an additional pole added to its + + + align:start position:0% +without an additional pole added to its +loop transmission yet if we added + + align:start position:0% +loop transmission yet if we added + + + align:start position:0% +loop transmission yet if we added +another pole to the loop transmission in + + align:start position:0% +another pole to the loop transmission in + + + align:start position:0% +another pole to the loop transmission in +addition to the 1 over s roll radical S + + align:start position:0% +addition to the 1 over s roll radical S + + + align:start position:0% +addition to the 1 over s roll radical S +roll-off Y we could be assured of at + + align:start position:0% +roll-off Y we could be assured of at + + + align:start position:0% +roll-off Y we could be assured of at +least 45 degrees of phase margin + + align:start position:0% +least 45 degrees of phase margin + + + align:start position:0% +least 45 degrees of phase margin +regardless of the location of the + + align:start position:0% +regardless of the location of the + + + align:start position:0% +regardless of the location of the +additional pole the the pole could give + + align:start position:0% +additional pole the the pole could give + + + align:start position:0% +additional pole the the pole could give +us at most minus 90 degrees a phase + + align:start position:0% +us at most minus 90 degrees a phase + + + align:start position:0% +us at most minus 90 degrees a phase +shift that combined with the 45 degrees + + align:start position:0% +shift that combined with the 45 degrees + + + align:start position:0% +shift that combined with the 45 degrees +of negative phase shift associated with + + align:start position:0% +of negative phase shift associated with + + + align:start position:0% +of negative phase shift associated with +the 1 over radical S roll-off would give + + align:start position:0% +the 1 over radical S roll-off would give + + + align:start position:0% +the 1 over radical S roll-off would give +us at most 135 degrees of negative phase + + align:start position:0% +us at most 135 degrees of negative phase + + + align:start position:0% +us at most 135 degrees of negative phase +shift associated with the AF product and + + align:start position:0% +shift associated with the AF product and + + + align:start position:0% +shift associated with the AF product and +so we have at least 45 degrees of phase + + align:start position:0% +so we have at least 45 degrees of phase + + + align:start position:0% +so we have at least 45 degrees of phase +margin we could have more depending on + + align:start position:0% +margin we could have more depending on + + + align:start position:0% +margin we could have more depending on +the exact value of the R 1 C 1 product + + align:start position:0% +the exact value of the R 1 C 1 product + + + align:start position:0% +the exact value of the R 1 C 1 product +but we're guaranteed to have at least 45 + + align:start position:0% +but we're guaranteed to have at least 45 + + + align:start position:0% +but we're guaranteed to have at least 45 +degrees of phase margin well that's fine + + align:start position:0% +degrees of phase margin well that's fine + + + align:start position:0% +degrees of phase margin well that's fine +the only bad news is that one can't + + align:start position:0% +the only bad news is that one can't + + + align:start position:0% +the only bad news is that one can't +realize a radical s Condor 1 over + + align:start position:0% +realize a radical s Condor 1 over + + + align:start position:0% +realize a radical s Condor 1 over +radical s kind of roll + + align:start position:0% +radical s kind of roll + + + align:start position:0% +radical s kind of roll +as a collection of lumped elements there + + align:start position:0% +as a collection of lumped elements there + + + align:start position:0% +as a collection of lumped elements there +are distributed systems that can give us + + align:start position:0% +are distributed systems that can give us + + + align:start position:0% +are distributed systems that can give us +that sort of a transfer function or + + align:start position:0% +that sort of a transfer function or + + + align:start position:0% +that sort of a transfer function or +transfer admittance but you can't do + + align:start position:0% +transfer admittance but you can't do + + + align:start position:0% +transfer admittance but you can't do +that as a as a collection of lumped + + align:start position:0% +that as a as a collection of lumped + + + align:start position:0% +that as a as a collection of lumped +elements but you can approximate it + + align:start position:0% +elements but you can approximate it + + + align:start position:0% +elements but you can approximate it +quite well and the way you do the + + align:start position:0% +quite well and the way you do the + + + align:start position:0% +quite well and the way you do the +approximation is as follows we've + + align:start position:0% +approximation is as follows we've + + + align:start position:0% +approximation is as follows we've +already looked at what happens if you + + align:start position:0% +already looked at what happens if you + + + align:start position:0% +already looked at what happens if you +take a single RC and we found out that + + align:start position:0% +take a single RC and we found out that + + + align:start position:0% +take a single RC and we found out that +in that case one over Y sub C looks + + align:start position:0% +in that case one over Y sub C looks + + + align:start position:0% +in that case one over Y sub C looks +something like so + + align:start position:0% +something like so + + + align:start position:0% +something like so +well now what I can do is add another + + align:start position:0% +well now what I can do is add another + + + align:start position:0% +well now what I can do is add another +parallel branch we might start out with + + align:start position:0% +parallel branch we might start out with + + + align:start position:0% +parallel branch we might start out with +this being a relatively large capacitor + + align:start position:0% +this being a relatively large capacitor + + + align:start position:0% +this being a relatively large capacitor +that gives us the 1 over s roll-off here + + align:start position:0% +that gives us the 1 over s roll-off here + + + align:start position:0% +that gives us the 1 over s roll-off here +we then get to a point the frequency + + align:start position:0% +we then get to a point the frequency + + + align:start position:0% +we then get to a point the frequency +where the admittance of the capacitor + + align:start position:0% +where the admittance of the capacitor + + + align:start position:0% +where the admittance of the capacitor +equals the conductance of this element + + align:start position:0% +equals the conductance of this element + + + align:start position:0% +equals the conductance of this element +and then things fall on a level off the + + align:start position:0% +and then things fall on a level off the + + + align:start position:0% +and then things fall on a level off the +admittance gets no lower we mine now + + align:start position:0% +admittance gets no lower we mine now + + + align:start position:0% +admittance gets no lower we mine now +could add a smaller capacitor and maybe + + align:start position:0% +could add a smaller capacitor and maybe + + + align:start position:0% +could add a smaller capacitor and maybe +another resistor and now what would + + align:start position:0% +another resistor and now what would + + + align:start position:0% +another resistor and now what would +happen is that that at some higher + + align:start position:0% +happen is that that at some higher + + + align:start position:0% +happen is that that at some higher +frequency this capacitor would become + + align:start position:0% +frequency this capacitor would become + + + align:start position:0% +frequency this capacitor would become +important it would now shunt this path + + align:start position:0% +important it would now shunt this path + + + align:start position:0% +important it would now shunt this path +both this capacitor and this resistor + + align:start position:0% +both this capacitor and this resistor + + + align:start position:0% +both this capacitor and this resistor +are smaller in value than their the + + align:start position:0% +are smaller in value than their the + + + align:start position:0% +are smaller in value than their the +corresponding elements in the top rung + + align:start position:0% +corresponding elements in the top rung + + + align:start position:0% +corresponding elements in the top rung +and the net result there might be to + + align:start position:0% +and the net result there might be to + + + align:start position:0% +and the net result there might be to +give us another region of one over s + + align:start position:0% +give us another region of one over s + + + align:start position:0% +give us another region of one over s +roll-off and then another flat region + + align:start position:0% +roll-off and then another flat region + + + align:start position:0% +roll-off and then another flat region +and I think now you can see what we + + align:start position:0% +and I think now you can see what we + + + align:start position:0% +and I think now you can see what we +might do we continue to build up our + + align:start position:0% +might do we continue to build up our + + + align:start position:0% +might do we continue to build up our +network with parallel RC chunks and the + + align:start position:0% +network with parallel RC chunks and the + + + align:start position:0% +network with parallel RC chunks and the +result on one over YC is to have a 1 + + align:start position:0% +result on one over YC is to have a 1 + + + align:start position:0% +result on one over YC is to have a 1 +over s roll-off a flat region a 1 over s + + align:start position:0% +over s roll-off a flat region a 1 over s + + + align:start position:0% +over s roll-off a flat region a 1 over s +roll-off a flat region and so forth and + + align:start position:0% +roll-off a flat region and so forth and + + + align:start position:0% +roll-off a flat region and so forth and +if we space the poles and zeros + + align:start position:0% +if we space the poles and zeros + + + align:start position:0% +if we space the poles and zeros +associated with this transfer function + + align:start position:0% +associated with this transfer function + + + align:start position:0% +associated with this transfer function +closely enough we'd begin to approximate + + align:start position:0% +closely enough we'd begin to approximate + + + align:start position:0% +closely enough we'd begin to approximate +a 1 over radical S roll-off we'd roll + + align:start position:0% +a 1 over radical S roll-off we'd roll + + + align:start position:0% +a 1 over radical S roll-off we'd roll +off as 1 over s half the time on + + align:start position:0% +off as 1 over s half the time on + + + align:start position:0% +off as 1 over s half the time on +logarithmic coordinates B flat half the + + align:start position:0% +logarithmic coordinates B flat half the + + + align:start position:0% +logarithmic coordinates B flat half the +time 1 + + align:start position:0% +time 1 + + + align:start position:0% +time 1 +erratic of one over s and so forth and + + align:start position:0% +erratic of one over s and so forth and + + + align:start position:0% +erratic of one over s and so forth and +begin to approximate a one over radical + + align:start position:0% +begin to approximate a one over radical + + + align:start position:0% +begin to approximate a one over radical +s roll-off so what we would choose to do + + align:start position:0% + + + + align:start position:0% + +is use a network it looks something like + + align:start position:0% +is use a network it looks something like + + + align:start position:0% +is use a network it looks something like +this if alphas a number larger than one + + align:start position:0% +this if alphas a number larger than one + + + align:start position:0% +this if alphas a number larger than one +if we start in the middle for example + + align:start position:0% +if we start in the middle for example + + + align:start position:0% +if we start in the middle for example +both resistors and capacitors get larger + + align:start position:0% +both resistors and capacitors get larger + + + align:start position:0% +both resistors and capacitors get larger +as we go this way in the ladder as we go + + align:start position:0% +as we go this way in the ladder as we go + + + align:start position:0% +as we go this way in the ladder as we go +to higher rungs and the ladder resistors + + align:start position:0% +to higher rungs and the ladder resistors + + + align:start position:0% +to higher rungs and the ladder resistors +and capacitors get smaller and you can + + align:start position:0% +and capacitors get smaller and you can + + + align:start position:0% +and capacitors get smaller and you can +chase that through and analyze that sort + + align:start position:0% +chase that through and analyze that sort + + + align:start position:0% +chase that through and analyze that sort +of a network the thing we're really + + align:start position:0% +of a network the thing we're really + + + align:start position:0% +of a network the thing we're really +interested in getting out of this + + align:start position:0% +interested in getting out of this + + + align:start position:0% +interested in getting out of this +network is 45 degrees of phase margin in + + align:start position:0% +network is 45 degrees of phase margin in + + + align:start position:0% +network is 45 degrees of phase margin in +our eventual system in other words we + + align:start position:0% +our eventual system in other words we + + + align:start position:0% +our eventual system in other words we +want the transfer admittance of that + + align:start position:0% +want the transfer admittance of that + + + align:start position:0% +want the transfer admittance of that +thing to have 45 degrees of actually + + align:start position:0% +thing to have 45 degrees of actually + + + align:start position:0% +thing to have 45 degrees of actually +positive phase shift if you look at the + + align:start position:0% +positive phase shift if you look at the + + + align:start position:0% +positive phase shift if you look at the +actual phase shift associated with the + + align:start position:0% +actual phase shift associated with the + + + align:start position:0% +actual phase shift associated with the +transfer admittance of course it ripples + + align:start position:0% +transfer admittance of course it ripples + + + align:start position:0% +transfer admittance of course it ripples +when you're when the transfer admittance + + align:start position:0% +when you're when the transfer admittance + + + align:start position:0% +when you're when the transfer admittance +is going as radical as asks why you have + + align:start position:0% +is going as radical as asks why you have + + + align:start position:0% +is going as radical as asks why you have +90 degrees of phase shift or approaching + + align:start position:0% +90 degrees of phase shift or approaching + + + align:start position:0% +90 degrees of phase shift or approaching +90 degrees of phase shift when the + + align:start position:0% +90 degrees of phase shift when the + + + align:start position:0% +90 degrees of phase shift when the +transfer admittance is constant with + + align:start position:0% +transfer admittance is constant with + + + align:start position:0% +transfer admittance is constant with +frequency you're approaching zero + + align:start position:0% +frequency you're approaching zero + + + align:start position:0% +frequency you're approaching zero +degrees of phase shift and in general + + align:start position:0% +degrees of phase shift and in general + + + align:start position:0% +degrees of phase shift and in general +just as the roll-off of that Network + + align:start position:0% +just as the roll-off of that Network + + + align:start position:0% +just as the roll-off of that Network +ripples so does the phase and you can + + align:start position:0% +ripples so does the phase and you can + + + align:start position:0% +ripples so does the phase and you can +control the amount of ripple really by + + align:start position:0% +control the amount of ripple really by + + + align:start position:0% +control the amount of ripple really by +the closeness of spacing a pole and zero + + align:start position:0% +the closeness of spacing a pole and zero + + + align:start position:0% +the closeness of spacing a pole and zero +pairs or equivalently by the choice of + + align:start position:0% +pairs or equivalently by the choice of + + + align:start position:0% +pairs or equivalently by the choice of +the quantity alpha in this network well + + align:start position:0% +the quantity alpha in this network well + + + align:start position:0% +the quantity alpha in this network well +it turns out that if you use only one + + align:start position:0% +it turns out that if you use only one + + + align:start position:0% +it turns out that if you use only one +pole and one zero per decade you get a + + align:start position:0% +pole and one zero per decade you get a + + + align:start position:0% +pole and one zero per decade you get a +very very good approximation to 45 + + align:start position:0% +very very good approximation to 45 + + + align:start position:0% +very very good approximation to 45 +degrees of phase shift associated with + + align:start position:0% +degrees of phase shift associated with + + + align:start position:0% +degrees of phase shift associated with +the transfer admittance you can choose + + align:start position:0% +the transfer admittance you can choose + + + align:start position:0% +the transfer admittance you can choose +that or you can can look at that + + align:start position:0% +that or you can can look at that + + + align:start position:0% +that or you can can look at that +situation users say a value of alpha + + align:start position:0% +situation users say a value of alpha + + + align:start position:0% +situation users say a value of alpha +that's the square root of 10 which gives + + align:start position:0% +that's the square root of 10 which gives + + + align:start position:0% +that's the square root of 10 which gives +you one pole and one zero in the + + align:start position:0% +you one pole and one zero in the + + + align:start position:0% +you one pole and one zero in the +transfer admittance of the network per + + align:start position:0% +transfer admittance of the network per + + + align:start position:0% +transfer admittance of the network per +decade and frequency and you find out + + align:start position:0% +decade and frequency and you find out + + + align:start position:0% +decade and frequency and you find out +that the peak to peak ripple associated + + align:start position:0% +that the peak to peak ripple associated + + + align:start position:0% +that the peak to peak ripple associated +with the phase shift of that network is + + align:start position:0% +with the phase shift of that network is + + + align:start position:0% +with the phase shift of that network is +only three degrees + + align:start position:0% +only three degrees + + + align:start position:0% +only three degrees +so we can approximate 45 degrees the + + align:start position:0% +so we can approximate 45 degrees the + + + align:start position:0% +so we can approximate 45 degrees the +desired value and the peak to peak + + align:start position:0% +desired value and the peak to peak + + + align:start position:0% +desired value and the peak to peak +ripple associated without approximation + + align:start position:0% +ripple associated without approximation + + + align:start position:0% +ripple associated without approximation +assuming that all of the elements had + + align:start position:0% +assuming that all of the elements had + + + align:start position:0% +assuming that all of the elements had +had the specified values there's no + + align:start position:0% +had the specified values there's no + + + align:start position:0% +had the specified values there's no +component tolerance would only be 3 + + align:start position:0% +component tolerance would only be 3 + + + align:start position:0% +component tolerance would only be 3 +degrees well in order to see how that + + align:start position:0% +degrees well in order to see how that + + + align:start position:0% +degrees well in order to see how that +works we've built up such a network and + + align:start position:0% +works we've built up such a network and + + + align:start position:0% +works we've built up such a network and +and here we have they look a little bit + + align:start position:0% +and here we have they look a little bit + + + align:start position:0% +and here we have they look a little bit +unwieldy this happens to be an 11 wrong + + align:start position:0% +unwieldy this happens to be an 11 wrong + + + align:start position:0% +unwieldy this happens to be an 11 wrong +ladder and what we have are of course + + align:start position:0% +ladder and what we have are of course + + + align:start position:0% +ladder and what we have are of course +simply 11 parallel RC sections this + + align:start position:0% +simply 11 parallel RC sections this + + + align:start position:0% +simply 11 parallel RC sections this +network gives us a 1 over radical s + + align:start position:0% +network gives us a 1 over radical s + + + align:start position:0% +network gives us a 1 over radical s +roll-off from several megahertz to + + align:start position:0% +roll-off from several megahertz to + + + align:start position:0% +roll-off from several megahertz to +fractions of a Hertz again using one RC + + align:start position:0% +fractions of a Hertz again using one RC + + + align:start position:0% +fractions of a Hertz again using one RC +section per decade we get that sort of + + align:start position:0% +section per decade we get that sort of + + + align:start position:0% +section per decade we get that sort of +performance with this kind of a network + + align:start position:0% +performance with this kind of a network + + + align:start position:0% +performance with this kind of a network +what I'd like to do is is investigate + + align:start position:0% +what I'd like to do is is investigate + + + align:start position:0% +what I'd like to do is is investigate +how that sort of a network stabilizes a + + align:start position:0% +how that sort of a network stabilizes a + + + align:start position:0% +how that sort of a network stabilizes a +system pretty much independent of where + + align:start position:0% +system pretty much independent of where + + + align:start position:0% +system pretty much independent of where +we locate an additional pole in the loop + + align:start position:0% +we locate an additional pole in the loop + + + align:start position:0% +we locate an additional pole in the loop +here we have our experimental setup this + + align:start position:0% +here we have our experimental setup this + + + align:start position:0% +here we have our experimental setup this +is a little bit different from the the + + align:start position:0% +is a little bit different from the the + + + align:start position:0% +is a little bit different from the the +past one what I have once again is is + + align:start position:0% +past one what I have once again is is + + + align:start position:0% +past one what I have once again is is +the power supply powering everything a + + align:start position:0% +the power supply powering everything a + + + align:start position:0% +the power supply powering everything a +generator that lets us put steps into + + align:start position:0% +generator that lets us put steps into + + + align:start position:0% +generator that lets us put steps into +our circuit we've changed the board in + + align:start position:0% +our circuit we've changed the board in + + + align:start position:0% +our circuit we've changed the board in +this case here's the circuit itself we + + align:start position:0% +this case here's the circuit itself we + + + align:start position:0% +this case here's the circuit itself we +have the 301 a or the 101 a type app + + align:start position:0% +have the 301 a or the 101 a type app + + + align:start position:0% +have the 301 a or the 101 a type app +let's buffer amplifier and a series of + + align:start position:0% +let's buffer amplifier and a series of + + + align:start position:0% +let's buffer amplifier and a series of +switches on the front the first of all + + align:start position:0% +switches on the front the first of all + + + align:start position:0% +switches on the front the first of all +let us select from various types of + + align:start position:0% +let us select from various types of + + + align:start position:0% +let us select from various types of +compensation also let us select the R 1 + + align:start position:0% +compensation also let us select the R 1 + + + align:start position:0% +compensation also let us select the R 1 +C 1 product so that's what these three + + align:start position:0% +C 1 product so that's what these three + + + align:start position:0% +C 1 product so that's what these three +switches do and what I'd like to + + align:start position:0% +switches do and what I'd like to + + + align:start position:0% +switches do and what I'd like to +initially look at is the behavior of the + + align:start position:0% +initially look at is the behavior of the + + + align:start position:0% +initially look at is the behavior of the +system when we have a single pole + + align:start position:0% +system when we have a single pole + + + align:start position:0% +system when we have a single pole +roll-off associated with the amplifier + + align:start position:0% +roll-off associated with the amplifier + + + align:start position:0% +roll-off associated with the amplifier +and we get that by moving the right hat + + align:start position:0% +and we get that by moving the right hat + + + align:start position:0% +and we get that by moving the right hat +or having the right hand switch in the + + align:start position:0% +or having the right hand switch in the + + + align:start position:0% +or having the right hand switch in the +upward position and we now have removed + + align:start position:0% +upward position and we now have removed + + + align:start position:0% +upward position and we now have removed +the additional pole in the loop the R is + + align:start position:0% +the additional pole in the loop the R is + + + align:start position:0% +the additional pole in the loop the R is +quite small in the seasoned open circuit + + align:start position:0% +quite small in the seasoned open circuit + + + align:start position:0% +quite small in the seasoned open circuit +so we've now removed the additional pole + + align:start position:0% +so we've now removed the additional pole + + + align:start position:0% +so we've now removed the additional pole +and the result of that of course is to + + align:start position:0% +and the result of that of course is to + + + align:start position:0% +and the result of that of course is to +give us effectively an exponential kind + + align:start position:0% +give us effectively an exponential kind + + + align:start position:0% +give us effectively an exponential kind +of response we'd expect when when our + + align:start position:0% +of response we'd expect when when our + + + align:start position:0% +of response we'd expect when when our +blue + + align:start position:0% +blue + + + align:start position:0% +blue +was rolling off as one over s or + + align:start position:0% +was rolling off as one over s or + + + align:start position:0% +was rolling off as one over s or +proportional to 1 over s we get a have a + + align:start position:0% +proportional to 1 over s we get a have a + + + align:start position:0% +proportional to 1 over s we get a have a +first-order system we've chosen numbers + + align:start position:0% +first-order system we've chosen numbers + + + align:start position:0% +first-order system we've chosen numbers +so the crossover in the loop occurs well + + align:start position:0% +so the crossover in the loop occurs well + + + align:start position:0% +so the crossover in the loop occurs well +below any additional phase shifts + + align:start position:0% +below any additional phase shifts + + + align:start position:0% +below any additional phase shifts +associated with the amplifier itself so + + align:start position:0% +associated with the amplifier itself so + + + align:start position:0% +associated with the amplifier itself so +we get a response that looks very very + + align:start position:0% +we get a response that looks very very + + + align:start position:0% +we get a response that looks very very +nearly first-order now let's begin to + + align:start position:0% +nearly first-order now let's begin to + + + align:start position:0% +nearly first-order now let's begin to +add additional poles let me start out + + align:start position:0% +add additional poles let me start out + + + align:start position:0% +add additional poles let me start out +putting in a pole at a megahertz well + + align:start position:0% +putting in a pole at a megahertz well + + + align:start position:0% +putting in a pole at a megahertz well +that doesn't really have much effect on + + align:start position:0% +that doesn't really have much effect on + + + align:start position:0% +that doesn't really have much effect on +the response and say here's a pole going + + align:start position:0% +the response and say here's a pole going + + + align:start position:0% +the response and say here's a pole going +into the megahertz that's actually + + align:start position:0% +into the megahertz that's actually + + + align:start position:0% +into the megahertz that's actually +beyond crossover in this loop and so + + align:start position:0% +beyond crossover in this loop and so + + + align:start position:0% +beyond crossover in this loop and so +there's very little change and there's + + align:start position:0% +there's very little change and there's + + + align:start position:0% +there's very little change and there's +the response we see just a hint of + + align:start position:0% +the response we see just a hint of + + + align:start position:0% +the response we see just a hint of +overshoot but really nothing very + + align:start position:0% +overshoot but really nothing very + + + align:start position:0% +overshoot but really nothing very +dramatic let me move the additional pole + + align:start position:0% +dramatic let me move the additional pole + + + align:start position:0% +dramatic let me move the additional pole +back to a hundred kilohertz by + + align:start position:0% +back to a hundred kilohertz by + + + align:start position:0% +back to a hundred kilohertz by +appropriate choice of the r1 c1 product + + align:start position:0% +appropriate choice of the r1 c1 product + + + align:start position:0% +appropriate choice of the r1 c1 product +I do that by throwing this middle switch + + align:start position:0% +I do that by throwing this middle switch + + + align:start position:0% +I do that by throwing this middle switch +down well now things are getting worse + + align:start position:0% +down well now things are getting worse + + + align:start position:0% +down well now things are getting worse +now the pole actually is occurring in + + align:start position:0% +now the pole actually is occurring in + + + align:start position:0% +now the pole actually is occurring in +the vicinity of crossover in the overall + + align:start position:0% +the vicinity of crossover in the overall + + + align:start position:0% +the vicinity of crossover in the overall +loop and so now we're down to something + + align:start position:0% +loop and so now we're down to something + + + align:start position:0% +loop and so now we're down to something +on the order of 40 degrees 30 degrees of + + align:start position:0% +on the order of 40 degrees 30 degrees of + + + align:start position:0% +on the order of 40 degrees 30 degrees of +phase margin possibly as I say the pole + + align:start position:0% +phase margin possibly as I say the pole + + + align:start position:0% +phase margin possibly as I say the pole +is probably actually a little bit above + + align:start position:0% +is probably actually a little bit above + + + align:start position:0% +is probably actually a little bit above +crossover and so we we get some + + align:start position:0% +crossover and so we we get some + + + align:start position:0% +crossover and so we we get some +significant overshoot let me move the + + align:start position:0% +significant overshoot let me move the + + + align:start position:0% +significant overshoot let me move the +pole down another decade to 10 kilohertz + + align:start position:0% +pole down another decade to 10 kilohertz + + + align:start position:0% +pole down another decade to 10 kilohertz +this is again lowering or increasing the + + align:start position:0% +this is again lowering or increasing the + + + align:start position:0% +this is again lowering or increasing the +value of the r1 c1 product things get + + align:start position:0% +value of the r1 c1 product things get + + + align:start position:0% +value of the r1 c1 product things get +much worse now we're not settling by the + + align:start position:0% +much worse now we're not settling by the + + + align:start position:0% +much worse now we're not settling by the +time the square wave comes along let me + + align:start position:0% +time the square wave comes along let me + + + align:start position:0% +time the square wave comes along let me +slow the generator but now we have + + align:start position:0% +slow the generator but now we have + + + align:start position:0% +slow the generator but now we have +considerable overshoot we're putting in + + align:start position:0% +considerable overshoot we're putting in + + + align:start position:0% +considerable overshoot we're putting in +a three division step and we're getting + + align:start position:0% +a three division step and we're getting + + + align:start position:0% +a three division step and we're getting +60% overshoot or something like that + + align:start position:0% +60% overshoot or something like that + + + align:start position:0% +60% overshoot or something like that +very prolonged transient very poorly + + align:start position:0% +very prolonged transient very poorly + + + align:start position:0% +very prolonged transient very poorly +damn let's try it just one more time + + align:start position:0% +damn let's try it just one more time + + + align:start position:0% +damn let's try it just one more time +that was it with a 10 kilohertz pole + + align:start position:0% +that was it with a 10 kilohertz pole + + + align:start position:0% +that was it with a 10 kilohertz pole +location here's one at 1 kilohertz again + + align:start position:0% +location here's one at 1 kilohertz again + + + align:start position:0% +location here's one at 1 kilohertz again +things haven't quite settled out let me + + align:start position:0% +things haven't quite settled out let me + + + align:start position:0% +things haven't quite settled out let me +slow the generator even further we can + + align:start position:0% +slow the generator even further we can + + + align:start position:0% +slow the generator even further we can +see once again very very nearly a + + align:start position:0% +see once again very very nearly a + + + align:start position:0% +see once again very very nearly a +hundred percent overshoot something like + + align:start position:0% +hundred percent overshoot something like + + + align:start position:0% +hundred percent overshoot something like +90 percent overshoot a very very + + align:start position:0% +90 percent overshoot a very very + + + align:start position:0% +90 percent overshoot a very very +prolonged settling + + align:start position:0% +prolonged settling + + + align:start position:0% +prolonged settling +let's see if we can do it just one more + + align:start position:0% +let's see if we can do it just one more + + + align:start position:0% +let's see if we can do it just one more +time move the pole down to a hundred + + align:start position:0% +time move the pole down to a hundred + + + align:start position:0% +time move the pole down to a hundred +Hertz and I don't know whether we can + + align:start position:0% +Hertz and I don't know whether we can + + + align:start position:0% +Hertz and I don't know whether we can +slow things enough to observe that or + + align:start position:0% +slow things enough to observe that or + + + align:start position:0% +slow things enough to observe that or +not but I'm just going to lower drive + + align:start position:0% +not but I'm just going to lower drive + + + align:start position:0% +not but I'm just going to lower drive +frequencies at present and here we see a + + align:start position:0% +frequencies at present and here we see a + + + align:start position:0% +frequencies at present and here we see a +very very poorly damped transient let's + + align:start position:0% +very very poorly damped transient let's + + + align:start position:0% +very very poorly damped transient let's +go back to one that's a little bit + + align:start position:0% +go back to one that's a little bit + + + align:start position:0% +go back to one that's a little bit +easier to observe here we are again with + + align:start position:0% +easier to observe here we are again with + + + align:start position:0% +easier to observe here we are again with +a transient response that corresponds to + + align:start position:0% +a transient response that corresponds to + + + align:start position:0% +a transient response that corresponds to +a 1 kilohertz pole location associated + + align:start position:0% +a 1 kilohertz pole location associated + + + align:start position:0% +a 1 kilohertz pole location associated +with R 1 C 1 so we see that when we use + + align:start position:0% +with R 1 C 1 so we see that when we use + + + align:start position:0% +with R 1 C 1 so we see that when we use +that sort of compensation the one over s + + align:start position:0% +that sort of compensation the one over s + + + align:start position:0% +that sort of compensation the one over s +compensation in the loop where we can + + align:start position:0% +compensation in the loop where we can + + + align:start position:0% +compensation in the loop where we can +add an additional pole we're able to get + + align:start position:0% +add an additional pole we're able to get + + + align:start position:0% +add an additional pole we're able to get +into very very severe stability problems + + align:start position:0% +into very very severe stability problems + + + align:start position:0% +into very very severe stability problems +we have another version of the one over + + align:start position:0% +we have another version of the one over + + + align:start position:0% +we have another version of the one over +radical S Network here somewhat better + + align:start position:0% +radical S Network here somewhat better + + + align:start position:0% +radical S Network here somewhat better +behaved Network or at least easier to + + align:start position:0% +behaved Network or at least easier to + + + align:start position:0% +behaved Network or at least easier to +use rather than have it spread out and + + align:start position:0% +use rather than have it spread out and + + + align:start position:0% +use rather than have it spread out and +in the Jacob's Ladder kind of + + align:start position:0% +in the Jacob's Ladder kind of + + + align:start position:0% +in the Jacob's Ladder kind of +configuration this is a little bit + + align:start position:0% +configuration this is a little bit + + + align:start position:0% +configuration this is a little bit +easier to use in our test setup let's go + + align:start position:0% +easier to use in our test setup let's go + + + align:start position:0% +easier to use in our test setup let's go +back to the situation where we have the + + align:start position:0% +back to the situation where we have the + + + align:start position:0% +back to the situation where we have the +the actual the R 1 C 1 pole located at + + align:start position:0% +the actual the R 1 C 1 pole located at + + + align:start position:0% +the actual the R 1 C 1 pole located at +very high frequencies and then let me + + align:start position:0% +very high frequencies and then let me + + + align:start position:0% +very high frequencies and then let me +add the network that compensates our + + align:start position:0% +add the network that compensates our + + + align:start position:0% +add the network that compensates our +loop for one over radical s behavior and + + align:start position:0% +loop for one over radical s behavior and + + + align:start position:0% +loop for one over radical s behavior and +let's look at at that response + + align:start position:0% + + + + align:start position:0% + +what happens here is that we get a very + + align:start position:0% +what happens here is that we get a very + + + align:start position:0% +what happens here is that we get a very +long tail if you will we spoke a little + + align:start position:0% +long tail if you will we spoke a little + + + align:start position:0% +long tail if you will we spoke a little +bit about this prolonged settling + + align:start position:0% +bit about this prolonged settling + + + align:start position:0% +bit about this prolonged settling +transient that results when we have a + + align:start position:0% +transient that results when we have a + + + align:start position:0% +transient that results when we have a +pole 0 doublet we looked at that in + + align:start position:0% +pole 0 doublet we looked at that in + + + align:start position:0% +pole 0 doublet we looked at that in +conjunction with the one over s squared + + align:start position:0% +conjunction with the one over s squared + + + align:start position:0% +conjunction with the one over s squared +compensation last time I mentioned the + + align:start position:0% +compensation last time I mentioned the + + + align:start position:0% +compensation last time I mentioned the +same kind of thing happens with a lag + + align:start position:0% +same kind of thing happens with a lag + + + align:start position:0% +same kind of thing happens with a lag +Network well here we have an extreme + + align:start position:0% +Network well here we have an extreme + + + align:start position:0% +Network well here we have an extreme +example of this kind of thing the effect + + align:start position:0% +example of this kind of thing the effect + + + align:start position:0% +example of this kind of thing the effect +of using the one over the approximation + + align:start position:0% +of using the one over the approximation + + + align:start position:0% +of using the one over the approximation +to the 1 over radical s roll-off is that + + align:start position:0% +to the 1 over radical s roll-off is that + + + align:start position:0% +to the 1 over radical s roll-off is that +we end up with an open-loop transfer + + align:start position:0% +we end up with an open-loop transfer + + + align:start position:0% +we end up with an open-loop transfer +function that has a poles and zeros + + align:start position:0% +function that has a poles and zeros + + + align:start position:0% +function that has a poles and zeros +alternated along the negative real axis + + align:start position:0% +alternated along the negative real axis + + + align:start position:0% +alternated along the negative real axis +and if we draw a root locus diagram for + + align:start position:0% +and if we draw a root locus diagram for + + + align:start position:0% +and if we draw a root locus diagram for +that we end up with a very large + + align:start position:0% +that we end up with a very large + + + align:start position:0% +that we end up with a very large +collection of pole 0 doublets in this + + align:start position:0% +collection of pole 0 doublets in this + + + align:start position:0% +collection of pole 0 doublets in this +case 11 and we get a very very long + + align:start position:0% +case 11 and we get a very very long + + + align:start position:0% +case 11 and we get a very very long +tortured settling to final value and we + + align:start position:0% +tortured settling to final value and we + + + align:start position:0% +tortured settling to final value and we +can see that final value is is has not + + align:start position:0% +can see that final value is is has not + + + align:start position:0% +can see that final value is is has not +even been reached here yet we go half + + align:start position:0% +even been reached here yet we go half + + + align:start position:0% +even been reached here yet we go half +way or so to final value quite quickly + + align:start position:0% +way or so to final value quite quickly + + + align:start position:0% +way or so to final value quite quickly +we go half way in a few microseconds + + align:start position:0% +we go half way in a few microseconds + + + align:start position:0% +we go half way in a few microseconds +we're 5 microseconds per division one + + align:start position:0% +we're 5 microseconds per division one + + + align:start position:0% +we're 5 microseconds per division one +and a half divisions vertically is half + + align:start position:0% +and a half divisions vertically is half + + + align:start position:0% +and a half divisions vertically is half +a final value but 500 microseconds later + + align:start position:0% +a final value but 500 microseconds later + + + align:start position:0% +a final value but 500 microseconds later +we're still settling and in fact if we + + align:start position:0% +we're still settling and in fact if we + + + align:start position:0% +we're still settling and in fact if we +examine things very carefully half a + + align:start position:0% +examine things very carefully half a + + + align:start position:0% +examine things very carefully half a +millisecond there are 5 milliseconds + + align:start position:0% +millisecond there are 5 milliseconds + + + align:start position:0% +millisecond there are 5 milliseconds +later the transient response is still + + align:start position:0% +later the transient response is still + + + align:start position:0% +later the transient response is still +settling and that reflects the + + align:start position:0% +settling and that reflects the + + + align:start position:0% +settling and that reflects the +collection of closely spaced called zero + + align:start position:0% +collection of closely spaced called zero + + + align:start position:0% +collection of closely spaced called zero +doublets that result when this sort of + + align:start position:0% +doublets that result when this sort of + + + align:start position:0% +doublets that result when this sort of +compensation is used the good news is + + align:start position:0% +compensation is used the good news is + + + align:start position:0% +compensation is used the good news is +that we get very dramatically improved + + align:start position:0% +that we get very dramatically improved + + + align:start position:0% +that we get very dramatically improved +stability as we add capacitive loads or + + align:start position:0% +stability as we add capacitive loads or + + + align:start position:0% +stability as we add capacitive loads or +an additional pole in the loop + + align:start position:0% +an additional pole in the loop + + + align:start position:0% +an additional pole in the loop +transmission let me first of all add the + + align:start position:0% +transmission let me first of all add the + + + align:start position:0% +transmission let me first of all add the +pole at at a hundred or at one megahertz + + align:start position:0% +pole at at a hundred or at one megahertz + + + align:start position:0% +pole at at a hundred or at one megahertz +again not much happens that is a + + align:start position:0% +again not much happens that is a + + + align:start position:0% +again not much happens that is a +sufficiently high frequency so that not + + align:start position:0% +sufficiently high frequency so that not + + + align:start position:0% +sufficiently high frequency so that not +much changes but now let's go to 100 + + align:start position:0% +much changes but now let's go to 100 + + + align:start position:0% +much changes but now let's go to 100 +kilohertz and this was a case where we + + align:start position:0% +kilohertz and this was a case where we + + + align:start position:0% +kilohertz and this was a case where we +were beginning to get measurable + + align:start position:0% +were beginning to get measurable + + + align:start position:0% +were beginning to get measurable +significant overshoot when we used one + + align:start position:0% +significant overshoot when we used one + + + align:start position:0% +significant overshoot when we used one +over s compensation + + align:start position:0% +over s compensation + + + align:start position:0% +over s compensation +here things are still very well-behaved + + align:start position:0% +here things are still very well-behaved + + + align:start position:0% +here things are still very well-behaved +in fact we really can't discern any + + align:start position:0% +in fact we really can't discern any + + + align:start position:0% +in fact we really can't discern any +overshoot a little ripple but but we + + align:start position:0% +overshoot a little ripple but but we + + + align:start position:0% +overshoot a little ripple but but we +really don't see any overshoot + + align:start position:0% +really don't see any overshoot + + + align:start position:0% +really don't see any overshoot +let's move the pole back to 10 kilohertz + + align:start position:0% +let's move the pole back to 10 kilohertz + + + align:start position:0% +let's move the pole back to 10 kilohertz +getting a little bit of overshoot but + + align:start position:0% +getting a little bit of overshoot but + + + align:start position:0% +getting a little bit of overshoot but +very very well-behaved response now + + align:start position:0% +very very well-behaved response now + + + align:start position:0% +very very well-behaved response now +let's go to a kilohertz rather than 10 + + align:start position:0% +let's go to a kilohertz rather than 10 + + + align:start position:0% +let's go to a kilohertz rather than 10 +kilohertz do this okay there we are with + + align:start position:0% +kilohertz do this okay there we are with + + + align:start position:0% +kilohertz do this okay there we are with +the network giving us a pole at at one + + align:start position:0% +the network giving us a pole at at one + + + align:start position:0% +the network giving us a pole at at one +kilohertz very well behaved response + + align:start position:0% +kilohertz very well behaved response + + + align:start position:0% +kilohertz very well behaved response +reflecting the approximately 45 degrees + + align:start position:0% +reflecting the approximately 45 degrees + + + align:start position:0% +reflecting the approximately 45 degrees +of phase margin let's go to a hundred + + align:start position:0% +of phase margin let's go to a hundred + + + align:start position:0% +of phase margin let's go to a hundred +Hertz things get slower fact much slower + + align:start position:0% +Hertz things get slower fact much slower + + + align:start position:0% +Hertz things get slower fact much slower +but the basic shape of the response now + + align:start position:0% +but the basic shape of the response now + + + align:start position:0% +but the basic shape of the response now +remains almost invariant here's the + + align:start position:0% +remains almost invariant here's the + + + align:start position:0% +remains almost invariant here's the +response with the RC pole located at a + + align:start position:0% +response with the RC pole located at a + + + align:start position:0% +response with the RC pole located at a +hundred Hertz here's the response with + + align:start position:0% +hundred Hertz here's the response with + + + align:start position:0% +hundred Hertz here's the response with +it located to the kilohertz comparable + + align:start position:0% +it located to the kilohertz comparable + + + align:start position:0% +it located to the kilohertz comparable +kinds of responses in terms of stability + + align:start position:0% +kinds of responses in terms of stability + + + align:start position:0% +kinds of responses in terms of stability +a little bit more overshoot here I think + + align:start position:0% +a little bit more overshoot here I think + + + align:start position:0% +a little bit more overshoot here I think +that reflects the ripple in the phase + + align:start position:0% +that reflects the ripple in the phase + + + align:start position:0% +that reflects the ripple in the phase +curve and probably the ripple is more + + align:start position:0% +curve and probably the ripple is more + + + align:start position:0% +curve and probably the ripple is more +than three degrees peak to peak because + + align:start position:0% +than three degrees peak to peak because + + + align:start position:0% +than three degrees peak to peak because +of component tolerances let's locate the + + align:start position:0% +of component tolerances let's locate the + + + align:start position:0% +of component tolerances let's locate the +pole at ten Hertz we weren't even able + + align:start position:0% +pole at ten Hertz we weren't even able + + + align:start position:0% +pole at ten Hertz we weren't even able +to do that with one over s compensation + + align:start position:0% +to do that with one over s compensation + + + align:start position:0% +to do that with one over s compensation +things do get slower but we have a still + + align:start position:0% +things do get slower but we have a still + + + align:start position:0% +things do get slower but we have a still +a very well behaved response not + + align:start position:0% +a very well behaved response not + + + align:start position:0% +a very well behaved response not +excessive overshoot and so we're able to + + align:start position:0% +excessive overshoot and so we're able to + + + align:start position:0% +excessive overshoot and so we're able to +stabilize the system notice that as we + + align:start position:0% +stabilize the system notice that as we + + + align:start position:0% +stabilize the system notice that as we +did this I've been moving the pole over + + align:start position:0% +did this I've been moving the pole over + + + align:start position:0% +did this I've been moving the pole over +five decades I started at a megahertz + + align:start position:0% +five decades I started at a megahertz + + + align:start position:0% +five decades I started at a megahertz +got all the way down to ten Hertz and we + + align:start position:0% +got all the way down to ten Hertz and we + + + align:start position:0% +got all the way down to ten Hertz and we +still get very very acceptable transient + + align:start position:0% +still get very very acceptable transient + + + align:start position:0% +still get very very acceptable transient +response so as the pole moves over in + + align:start position:0% +response so as the pole moves over in + + + align:start position:0% +response so as the pole moves over in +this case ten decades in frequency we + + align:start position:0% +this case ten decades in frequency we + + + align:start position:0% +this case ten decades in frequency we +still get very acceptable performance + + align:start position:0% + + + + align:start position:0% + +well one may question the practicality + + align:start position:0% +well one may question the practicality + + + align:start position:0% +well one may question the practicality +of using this sort of a network to + + align:start position:0% +of using this sort of a network to + + + align:start position:0% +of using this sort of a network to +compensate an operational amplifier + + align:start position:0% +compensate an operational amplifier + + + align:start position:0% +compensate an operational amplifier +fortunately there's a middle ground we + + align:start position:0% +fortunately there's a middle ground we + + + align:start position:0% +fortunately there's a middle ground we +found out that an approximation that + + align:start position:0% +found out that an approximation that + + + align:start position:0% +found out that an approximation that +uses one pole in one zero per decade did + + align:start position:0% +uses one pole in one zero per decade did + + + align:start position:0% +uses one pole in one zero per decade did +a pretty good job let's consider a very + + align:start position:0% +a pretty good job let's consider a very + + + align:start position:0% +a pretty good job let's consider a very +crude approximation to the ladder just a + + align:start position:0% +crude approximation to the ladder just a + + + align:start position:0% +crude approximation to the ladder just a +two wrong ladder and in fact let's + + align:start position:0% +two wrong ladder and in fact let's + + + align:start position:0% +two wrong ladder and in fact let's +choose things such that the capacitors + + align:start position:0% +choose things such that the capacitors + + + align:start position:0% +choose things such that the capacitors +have a ratio of ten to one by doing that + + align:start position:0% +have a ratio of ten to one by doing that + + + align:start position:0% +have a ratio of ten to one by doing that +we can end up with a very crude + + align:start position:0% +we can end up with a very crude + + + align:start position:0% +we can end up with a very crude +approximation to the one over radical s + + align:start position:0% +approximation to the one over radical s + + + align:start position:0% +approximation to the one over radical s +roll-off let's see what I've shown here + + align:start position:0% +roll-off let's see what I've shown here + + + align:start position:0% +roll-off let's see what I've shown here +normalized to attend to the sixth Radian + + align:start position:0% +normalized to attend to the sixth Radian + + + align:start position:0% +normalized to attend to the sixth Radian +per second crossover frequency is first + + align:start position:0% +per second crossover frequency is first + + + align:start position:0% +per second crossover frequency is first +of all a transfer function that's + + align:start position:0% +of all a transfer function that's + + + align:start position:0% +of all a transfer function that's +falling off as 1 over s that has minus + + align:start position:0% +falling off as 1 over s that has minus + + + align:start position:0% +falling off as 1 over s that has minus +90 degrees a phase shift at all + + align:start position:0% +90 degrees a phase shift at all + + + align:start position:0% +90 degrees a phase shift at all +frequencies I then show a network or an + + align:start position:0% +frequencies I then show a network or an + + + align:start position:0% +frequencies I then show a network or an +amplifier that's rolling off as 1 over + + align:start position:0% +amplifier that's rolling off as 1 over + + + align:start position:0% +amplifier that's rolling off as 1 over +radical s that has minus 45 degrees a + + align:start position:0% +radical s that has minus 45 degrees a + + + align:start position:0% +radical s that has minus 45 degrees a +phase shift at all frequencies here I + + align:start position:0% +phase shift at all frequencies here I + + + align:start position:0% +phase shift at all frequencies here I +show a transfer function that rolls off + + align:start position:0% +show a transfer function that rolls off + + + align:start position:0% +show a transfer function that rolls off +as 1 over s from the unity gain + + align:start position:0% +as 1 over s from the unity gain + + + align:start position:0% +as 1 over s from the unity gain +frequency back to a decade below the + + align:start position:0% +frequency back to a decade below the + + + align:start position:0% +frequency back to a decade below the +unity gain frequency it then flattens + + align:start position:0% +unity gain frequency it then flattens + + + align:start position:0% +unity gain frequency it then flattens +out for another decade from here to here + + align:start position:0% +out for another decade from here to here + + + align:start position:0% +out for another decade from here to here +and then once again rolls off as 1 over + + align:start position:0% +and then once again rolls off as 1 over + + + align:start position:0% +and then once again rolls off as 1 over +s below that so this is a very crude + + align:start position:0% +s below that so this is a very crude + + + align:start position:0% +s below that so this is a very crude +approximation to the 1 over radical s + + align:start position:0% +approximation to the 1 over radical s + + + align:start position:0% +approximation to the 1 over radical s +kind of roll off the corresponding phase + + align:start position:0% +kind of roll off the corresponding phase + + + align:start position:0% +kind of roll off the corresponding phase +characteristics are like this but that's + + align:start position:0% +characteristics are like this but that's + + + align:start position:0% +characteristics are like this but that's +a very achievable Network we can do that + + align:start position:0% +a very achievable Network we can do that + + + align:start position:0% +a very achievable Network we can do that +as a say with with just two capacitors + + align:start position:0% +as a say with with just two capacitors + + + align:start position:0% +as a say with with just two capacitors +and a resistor as I've shown and let's + + align:start position:0% +and a resistor as I've shown and let's + + + align:start position:0% +and a resistor as I've shown and let's +look at the results of that let me + + align:start position:0% +look at the results of that let me + + + align:start position:0% +look at the results of that let me +remove the one over radical s kind of + + align:start position:0% +remove the one over radical s kind of + + + align:start position:0% +remove the one over radical s kind of +Network this one let's go back to the + + align:start position:0% +Network this one let's go back to the + + + align:start position:0% +Network this one let's go back to the +very high frequency location for the RC + + align:start position:0% +very high frequency location for the RC + + + align:start position:0% +very high frequency location for the RC +pole + + align:start position:0% +pole + + + align:start position:0% +pole +and let's speed up things now + + align:start position:0% + + + + align:start position:0% + +well what we find is again a delayed + + align:start position:0% +well what we find is again a delayed + + + align:start position:0% +well what we find is again a delayed +settling time this sort of compensation + + align:start position:0% +settling time this sort of compensation + + + align:start position:0% +settling time this sort of compensation +again gives us a pole-zero doublet if we + + align:start position:0% +again gives us a pole-zero doublet if we + + + align:start position:0% +again gives us a pole-zero doublet if we +look at it we get to about 90% of final + + align:start position:0% +look at it we get to about 90% of final + + + align:start position:0% +look at it we get to about 90% of final +value very quickly on the leading edge + + align:start position:0% +value very quickly on the leading edge + + + align:start position:0% +value very quickly on the leading edge +but it takes us much much longer the + + align:start position:0% +but it takes us much much longer the + + + align:start position:0% +but it takes us much much longer the +response is basically two Exponential's + + align:start position:0% +response is basically two Exponential's + + + align:start position:0% +response is basically two Exponential's +one of which has a much longer time + + align:start position:0% +one of which has a much longer time + + + align:start position:0% +one of which has a much longer time +constant than the other one and we see + + align:start position:0% +constant than the other one and we see + + + align:start position:0% +constant than the other one and we see +the quite prolonged settling to final + + align:start position:0% +the quite prolonged settling to final + + + align:start position:0% +the quite prolonged settling to final +value let's begin to add the pole this + + align:start position:0% +value let's begin to add the pole this + + + align:start position:0% +value let's begin to add the pole this +is with the additional pole loop at + + align:start position:0% +is with the additional pole loop at + + + align:start position:0% +is with the additional pole loop at +infinite frequency effectively now let's + + align:start position:0% +infinite frequency effectively now let's + + + align:start position:0% +infinite frequency effectively now let's +go ahead and add the pole at one + + align:start position:0% +go ahead and add the pole at one + + + align:start position:0% +go ahead and add the pole at one +megahertz again not much effect we see + + align:start position:0% +megahertz again not much effect we see + + + align:start position:0% +megahertz again not much effect we see +just a little peaking we can begin to + + align:start position:0% +just a little peaking we can begin to + + + align:start position:0% +just a little peaking we can begin to +lower the location of the additional + + align:start position:0% +lower the location of the additional + + + align:start position:0% +lower the location of the additional +pole in the loop here's 100 kilohertz + + align:start position:0% +pole in the loop here's 100 kilohertz + + + align:start position:0% +pole in the loop here's 100 kilohertz +well behaved 10 kilohertz notice this is + + align:start position:0% +well behaved 10 kilohertz notice this is + + + align:start position:0% +well behaved 10 kilohertz notice this is +actually better damped than the one + + align:start position:0% +actually better damped than the one + + + align:start position:0% +actually better damped than the one +corresponding to the pole location at + + align:start position:0% +corresponding to the pole location at + + + align:start position:0% +corresponding to the pole location at +100 kilohertz that's not surprising the + + align:start position:0% +100 kilohertz that's not surprising the + + + align:start position:0% +100 kilohertz that's not surprising the +phase of this network this very simple + + align:start position:0% +phase of this network this very simple + + + align:start position:0% +phase of this network this very simple +approximation to a 1 over radical S + + align:start position:0% +approximation to a 1 over radical S + + + align:start position:0% +approximation to a 1 over radical S +network change is far more violently as + + align:start position:0% +network change is far more violently as + + + align:start position:0% +network change is far more violently as +a function of frequency then does the + + align:start position:0% +a function of frequency then does the + + + align:start position:0% +a function of frequency then does the +one over radical s approximation using + + align:start position:0% +one over radical s approximation using + + + align:start position:0% +one over radical s approximation using +the much better + + align:start position:0% +the much better + + + align:start position:0% +the much better +ladder with considerably more and larger + + align:start position:0% +ladder with considerably more and larger + + + align:start position:0% +ladder with considerably more and larger +number of rungs so it's not surprising + + align:start position:0% +number of rungs so it's not surprising + + + align:start position:0% +number of rungs so it's not surprising +that relative stability is is more + + align:start position:0% +that relative stability is is more + + + align:start position:0% +that relative stability is is more +dependent on the exact location of the + + align:start position:0% +dependent on the exact location of the + + + align:start position:0% +dependent on the exact location of the +additional pole here's one of the + + align:start position:0% +additional pole here's one of the + + + align:start position:0% +additional pole here's one of the +kilohertz have to slow things down again + + align:start position:0% +kilohertz have to slow things down again + + + align:start position:0% +kilohertz have to slow things down again +relative to the pole location at 10 + + align:start position:0% +relative to the pole location at 10 + + + align:start position:0% +relative to the pole location at 10 +kilohertz we have poor stability at a + + align:start position:0% +kilohertz we have poor stability at a + + + align:start position:0% +kilohertz we have poor stability at a +hundred Hertz considerably poor + + align:start position:0% +hundred Hertz considerably poor + + + align:start position:0% +hundred Hertz considerably poor +stability once again and beyond this we + + align:start position:0% +stability once again and beyond this we + + + align:start position:0% +stability once again and beyond this we +begin to lose things quite dramatically + + align:start position:0% +begin to lose things quite dramatically + + + align:start position:0% +begin to lose things quite dramatically +but again at this point the one over s + + align:start position:0% +but again at this point the one over s + + + align:start position:0% +but again at this point the one over s +compensation was had just completely + + align:start position:0% +compensation was had just completely + + + align:start position:0% +compensation was had just completely +lost in fact we had a lot of trouble + + align:start position:0% +lost in fact we had a lot of trouble + + + align:start position:0% +lost in fact we had a lot of trouble +with one over s compensation when we + + align:start position:0% +with one over s compensation when we + + + align:start position:0% +with one over s compensation when we +located the pole at one kilohertz here + + align:start position:0% +located the pole at one kilohertz here + + + align:start position:0% +located the pole at one kilohertz here +the thing I hear the + + align:start position:0% +the thing I hear the + + + align:start position:0% +the thing I hear the +system is very well behaved with this + + align:start position:0% +system is very well behaved with this + + + align:start position:0% +system is very well behaved with this +very simple compensating network when + + align:start position:0% +very simple compensating network when + + + align:start position:0% +very simple compensating network when +the poles of 1 kilohertz if you look at + + align:start position:0% +the poles of 1 kilohertz if you look at + + + align:start position:0% +the poles of 1 kilohertz if you look at +at this in in detail you find that you + + align:start position:0% +at this in in detail you find that you + + + align:start position:0% +at this in in detail you find that you +can maintain something like 30 degrees + + align:start position:0% +can maintain something like 30 degrees + + + align:start position:0% +can maintain something like 30 degrees +of phase margin as a minimum until you + + align:start position:0% +of phase margin as a minimum until you + + + align:start position:0% +of phase margin as a minimum until you +move the additional pole back to + + align:start position:0% +move the additional pole back to + + + align:start position:0% +move the additional pole back to +somewhere on the order of a kilohertz or + + align:start position:0% +somewhere on the order of a kilohertz or + + + align:start position:0% +somewhere on the order of a kilohertz or +actually below that so you're able to + + align:start position:0% +actually below that so you're able to + + + align:start position:0% +actually below that so you're able to +move the pole from crossover back by + + align:start position:0% +move the pole from crossover back by + + + align:start position:0% +move the pole from crossover back by +approximately three decades before you + + align:start position:0% +approximately three decades before you + + + align:start position:0% +approximately three decades before you +begin to get into serious stability + + align:start position:0% +begin to get into serious stability + + + align:start position:0% +begin to get into serious stability +problems the implication is that we can + + align:start position:0% +problems the implication is that we can + + + align:start position:0% +problems the implication is that we can +design for a system with an uncertain + + align:start position:0% +design for a system with an uncertain + + + align:start position:0% +design for a system with an uncertain +pole location where the pole location + + align:start position:0% +pole location where the pole location + + + align:start position:0% +pole location where the pole location +varies over as much as three decades and + + align:start position:0% +varies over as much as three decades and + + + align:start position:0% +varies over as much as three decades and +still get acceptable stability with a + + align:start position:0% +still get acceptable stability with a + + + align:start position:0% +still get acceptable stability with a +very very simple compensating Network + + align:start position:0% +very very simple compensating Network + + + align:start position:0% +very very simple compensating Network +independent of the actual location of + + align:start position:0% +independent of the actual location of + + + align:start position:0% +independent of the actual location of +the pole to summarize very quickly we've + + align:start position:0% +the pole to summarize very quickly we've + + + align:start position:0% +the pole to summarize very quickly we've +compared special-purpose compensation + + align:start position:0% +compared special-purpose compensation + + + align:start position:0% +compared special-purpose compensation +compensation tailored to the specific + + align:start position:0% +compensation tailored to the specific + + + align:start position:0% +compensation tailored to the specific +application and we've we've compared + + align:start position:0% +application and we've we've compared + + + align:start position:0% +application and we've we've compared +that with what happens when we live with + + align:start position:0% +that with what happens when we live with + + + align:start position:0% +that with what happens when we live with +sort of the manufacturers recommendation + + align:start position:0% +sort of the manufacturers recommendation + + + align:start position:0% +sort of the manufacturers recommendation +in an internally compensated operational + + align:start position:0% +in an internally compensated operational + + + align:start position:0% +in an internally compensated operational +amplifier we found that we can either + + align:start position:0% +amplifier we found that we can either + + + align:start position:0% +amplifier we found that we can either +use single pole compensation where we + + align:start position:0% +use single pole compensation where we + + + align:start position:0% +use single pole compensation where we +tailor the constant associated with the + + align:start position:0% +tailor the constant associated with the + + + align:start position:0% +tailor the constant associated with the +compensation to the specific feedback + + align:start position:0% +compensation to the specific feedback + + + align:start position:0% +compensation to the specific feedback +attenuation used we improve performance + + align:start position:0% +attenuation used we improve performance + + + align:start position:0% +attenuation used we improve performance +compared to fixed single pole + + align:start position:0% +compared to fixed single pole + + + align:start position:0% +compared to fixed single pole +compensation we can use two pole + + align:start position:0% +compensation we can use two pole + + + align:start position:0% +compensation we can use two pole +compensation which gets us greatly + + align:start position:0% +compensation which gets us greatly + + + align:start position:0% +compensation which gets us greatly +improved these sensitivity compared to + + align:start position:0% +improved these sensitivity compared to + + + align:start position:0% +improved these sensitivity compared to +single pole compensation over a wide + + align:start position:0% +single pole compensation over a wide + + + align:start position:0% +single pole compensation over a wide +range of frequencies we can use + + align:start position:0% +range of frequencies we can use + + + align:start position:0% +range of frequencies we can use +compensation that includes a zero and + + align:start position:0% +compensation that includes a zero and + + + align:start position:0% +compensation that includes a zero and +that allows us to make up for one + + align:start position:0% +that allows us to make up for one + + + align:start position:0% +that allows us to make up for one +additional pole in the loop but it's + + align:start position:0% +additional pole in the loop but it's + + + align:start position:0% +additional pole in the loop but it's +dependent on our a good knowledge of + + align:start position:0% +dependent on our a good knowledge of + + + align:start position:0% +dependent on our a good knowledge of +where the additional pole is located and + + align:start position:0% +where the additional pole is located and + + + align:start position:0% +where the additional pole is located and +finally we're able to use a slow roll + + align:start position:0% +finally we're able to use a slow roll + + + align:start position:0% +finally we're able to use a slow roll +off kind of compensation that rolls off + + align:start position:0% +off kind of compensation that rolls off + + + align:start position:0% +off kind of compensation that rolls off +somewhere between 1 / s + and 0 and with + + align:start position:0% +somewhere between 1 / s + and 0 and with + + + align:start position:0% +somewhere between 1 / s + and 0 and with +that we're able to tolerate an + + align:start position:0% +that we're able to tolerate an + + + align:start position:0% +that we're able to tolerate an +additional pole added to the loop + + align:start position:0% +additional pole added to the loop + + + align:start position:0% +additional pole added to the loop +transmission over a very very wide range + + align:start position:0% +transmission over a very very wide range + + + align:start position:0% +transmission over a very very wide range +frequency's and still maintain + + align:start position:0% +frequency's and still maintain + + + align:start position:0% +frequency's and still maintain +acceptable stability that concludes this + + align:start position:0% +acceptable stability that concludes this + + + align:start position:0% +acceptable stability that concludes this +series of examples compensating the LM + + align:start position:0% +series of examples compensating the LM + + + align:start position:0% +series of examples compensating the LM +101 a type operational amplifier thank + + align:start position:0% +101 a type operational amplifier thank + + + align:start position:0% +101 a type operational amplifier thank +you \ No newline at end of file diff --git a/fnodeNO6gaQ.txt b/fnodeNO6gaQ.txt new file mode 100644 index 0000000000000000000000000000000000000000..3cd98e97a0468d612402351d3d6925f1179e2d5e --- /dev/null +++ b/fnodeNO6gaQ.txt @@ -0,0 +1,8387 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT open courseware continue + + align:start position:0% +will help MIT open courseware continue + + + align:start position:0% +will help MIT open courseware continue +to offer highquality educational + + align:start position:0% +to offer highquality educational + + + align:start position:0% +to offer highquality educational +resources for free to make a donation or + + align:start position:0% +resources for free to make a donation or + + + align:start position:0% +resources for free to make a donation or +view additional materials from hundreds + + align:start position:0% +view additional materials from hundreds + + + align:start position:0% +view additional materials from hundreds +of MIT courses visit MIT opencourseware + + align:start position:0% +of MIT courses visit MIT opencourseware + + + align:start position:0% +of MIT courses visit MIT opencourseware +at + + align:start position:0% + + + + align:start position:0% + +ocw.mit.edu what are tool activities and + + align:start position:0% +ocw.mit.edu what are tool activities and + + + align:start position:0% +ocw.mit.edu what are tool activities and +why does Lawrence call them tool + + align:start position:0% + + + + align:start position:0% + +activities this should be an easy + + align:start position:0% +activities this should be an easy + + + align:start position:0% +activities this should be an easy +question if you're doing any + + align:start position:0% + + + + align:start position:0% + +reading what does he mean by Tool + + align:start position:0% + + + + align:start position:0% + +activities I know some of you + + align:start position:0% +activities I know some of you + + + align:start position:0% +activities I know some of you +know you know you don't + + align:start position:0% +know you know you don't + + + align:start position:0% +know you know you don't +remember I guess you were doing homework + + align:start position:0% +remember I guess you were doing homework + + + align:start position:0% +remember I guess you were doing homework +instead of + + align:start position:0% +instead of + + + align:start position:0% +instead of +reading all right tool activities mean + + align:start position:0% +reading all right tool activities mean + + + align:start position:0% +reading all right tool activities mean +multi-purpose actions they're + + align:start position:0% +multi-purpose actions they're + + + align:start position:0% +multi-purpose actions they're +instinctive action + + align:start position:0% +instinctive action + + + align:start position:0% +instinctive action +patterns they do have a motivational + + align:start position:0% +patterns they do have a motivational + + + align:start position:0% +patterns they do have a motivational +component so they're classified as fixed + + align:start position:0% +component so they're classified as fixed + + + align:start position:0% +component so they're classified as fixed +action patterns rather than reflexes but + + align:start position:0% +action patterns rather than reflexes but + + + align:start position:0% +action patterns rather than reflexes but +they refer to multi-purpose actions that + + align:start position:0% +they refer to multi-purpose actions that + + + align:start position:0% +they refer to multi-purpose actions that +the very same they're components of many + + align:start position:0% +the very same they're components of many + + + align:start position:0% +the very same they're components of many +different fixed action + + align:start position:0% +different fixed action + + + align:start position:0% +different fixed action +patterns but they're also fixed action + + align:start position:0% +patterns but they're also fixed action + + + align:start position:0% +patterns but they're also fixed action +patterns of their own like + + align:start position:0% +patterns of their own like + + + align:start position:0% +patterns of their own like +Locomotion you know we use locomotion as + + align:start position:0% +Locomotion you know we use locomotion as + + + align:start position:0% +Locomotion you know we use locomotion as +part of the repetitive Behavior behind + + align:start position:0% +part of the repetitive Behavior behind + + + align:start position:0% +part of the repetitive Behavior behind +any almost very many other fixed + + align:start position:0% +any almost very many other fixed + + + align:start position:0% +any almost very many other fixed +action and the same is true of + + align:start position:0% +action and the same is true of + + + align:start position:0% +action and the same is true of +the orienting + + align:start position:0% + + + + align:start position:0% + +movements we'd make orienting + + align:start position:0% +movements we'd make orienting + + + align:start position:0% +movements we'd make orienting +movements in response to stimuli it's + + align:start position:0% +movements in response to stimuli it's + + + align:start position:0% +movements in response to stimuli it's +true and that makes them seem like + + align:start position:0% +true and that makes them seem like + + + align:start position:0% +true and that makes them seem like +reflexes but in fact they're part of + + align:start position:0% +reflexes but in fact they're part of + + + align:start position:0% +reflexes but in fact they're part of +many fixed action + + align:start position:0% + + + + align:start position:0% + +patterns and we don't just fit without + + align:start position:0% +patterns and we don't just fit without + + + align:start position:0% +patterns and we don't just fit without +even + + align:start position:0% +even + + + align:start position:0% +even +stimuli you know even if none of you are + + align:start position:0% +stimuli you know even if none of you are + + + align:start position:0% +stimuli you know even if none of you are +moving and I'm I don't just stare at + + align:start position:0% +moving and I'm I don't just stare at + + + align:start position:0% +moving and I'm I don't just stare at +one's place my eyes are always roaming + + align:start position:0% +one's place my eyes are always roaming + + + align:start position:0% +one's place my eyes are always roaming +around I'm making orienting + + align:start position:0% +around I'm making orienting + + + align:start position:0% +around I'm making orienting +movements grasping with the hands is the + + align:start position:0% +movements grasping with the hands is the + + + align:start position:0% +movements grasping with the hands is the +same so each of + + align:start position:0% +same so each of + + + align:start position:0% +same so each of +these major types of activities are tool + + align:start position:0% +these major types of activities are tool + + + align:start position:0% +these major types of activities are tool +activities and there's actually many + + align:start position:0% +activities and there's actually many + + + align:start position:0% +activities and there's actually many +variet ities of each one for a + + align:start position:0% +variet ities of each one for a + + + align:start position:0% +variet ities of each one for a +Locomotion is easiest to talk about + + align:start position:0% +Locomotion is easiest to talk about + + + align:start position:0% +Locomotion is easiest to talk about +there because we Define the various + + align:start position:0% +there because we Define the various + + + align:start position:0% +there because we Define the various +Gates especially in four-legged animals + + align:start position:0% +Gates especially in four-legged animals + + + align:start position:0% +Gates especially in four-legged animals +but humans still have various types of + + align:start position:0% +but humans still have various types of + + + align:start position:0% +but humans still have various types of +walking and running various speeds of + + align:start position:0% +walking and running various speeds of + + + align:start position:0% +walking and running various speeds of +running okay now what about the action + + align:start position:0% +running okay now what about the action + + + align:start position:0% +running okay now what about the action +specific + + align:start position:0% +specific + + + align:start position:0% +specific +potential Behind These and + + align:start position:0% +potential Behind These and + + + align:start position:0% +potential Behind These and +other exaction + + align:start position:0% +other exaction + + + align:start position:0% +other exaction +patterns + + align:start position:0% +patterns + + + align:start position:0% +patterns +we know + + align:start position:0% +we know + + + align:start position:0% +we know +that if they're like most fixed action + + align:start position:0% +that if they're like most fixed action + + + align:start position:0% +that if they're like most fixed action +patterns the the action specific + + align:start position:0% +patterns the the action specific + + + align:start position:0% +patterns the the action specific +potential meaning the level of + + align:start position:0% +potential meaning the level of + + + align:start position:0% +potential meaning the level of +motivation builds up over time well it + + align:start position:0% +motivation builds up over time well it + + + align:start position:0% +motivation builds up over time well it +doesn't build up at the same rate for + + align:start position:0% +doesn't build up at the same rate for + + + align:start position:0% +doesn't build up at the same rate for +different fix action + + align:start position:0% + + + + align:start position:0% + +patterns it tends to build up at a rate + + align:start position:0% +patterns it tends to build up at a rate + + + align:start position:0% +patterns it tends to build up at a rate +proportional to how often the pattern + + align:start position:0% +proportional to how often the pattern + + + align:start position:0% +proportional to how often the pattern +the the movement is + + align:start position:0% +the the movement is + + + align:start position:0% +the the movement is +needed + + align:start position:0% + + + + align:start position:0% + +and we know that many of these fixed + + align:start position:0% +and we know that many of these fixed + + + align:start position:0% +and we know that many of these fixed +action patterns like predatory behavior + + align:start position:0% +action patterns like predatory behavior + + + align:start position:0% +action patterns like predatory behavior +in the cat are actually a series of + + align:start position:0% +in the cat are actually a series of + + + align:start position:0% +in the cat are actually a series of +fixed they're inherited as a s as a + + align:start position:0% +fixed they're inherited as a s as a + + + align:start position:0% +fixed they're inherited as a s as a +series of different fixed action + + align:start position:0% +series of different fixed action + + + align:start position:0% +series of different fixed action +patterns but they become linked during + + align:start position:0% + + + + align:start position:0% + +development that is habits form + + align:start position:0% +development that is habits form + + + align:start position:0% +development that is habits form +depending on the experience of the + + align:start position:0% +depending on the experience of the + + + align:start position:0% +depending on the experience of the +animal usually with the mother in the + + align:start position:0% +animal usually with the mother in the + + + align:start position:0% +animal usually with the mother in the +case of predatory + + align:start position:0% +case of predatory + + + align:start position:0% +case of predatory +cats + + align:start position:0% +cats + + + align:start position:0% +cats +uh and the the various patterns become + + align:start position:0% +uh and the the various patterns become + + + align:start position:0% +uh and the the various patterns become +linked so then they're normally doing + + align:start position:0% +linked so then they're normally doing + + + align:start position:0% +linked so then they're normally doing +them the searching Locomotion and + + align:start position:0% +them the searching Locomotion and + + + align:start position:0% +them the searching Locomotion and +searching then stalking then bouncing + + align:start position:0% +searching then stalking then bouncing + + + align:start position:0% +searching then stalking then bouncing +and then the killing bite usually in + + align:start position:0% +and then the killing bite usually in + + + align:start position:0% +and then the killing bite usually in +that + + align:start position:0% +that + + + align:start position:0% +that +order + + align:start position:0% + + + + align:start position:0% + +so how frequently does the + + align:start position:0% +so how frequently does the + + + align:start position:0% +so how frequently does the +cat + + align:start position:0% +cat + + + align:start position:0% +cat +perform each of these + + align:start position:0% +perform each of these + + + align:start position:0% +perform each of these +behaviors + + align:start position:0% +behaviors + + + align:start position:0% +behaviors +well they perform stalking a lot more + + align:start position:0% +well they perform stalking a lot more + + + align:start position:0% +well they perform stalking a lot more +than they pounce because they have to + + align:start position:0% +than they pounce because they have to + + + align:start position:0% +than they pounce because they have to +stalk they have to search for prey the + + align:start position:0% +stalk they have to search for prey the + + + align:start position:0% +stalk they have to search for prey the +most before they find it so they're + + align:start position:0% +most before they find it so they're + + + align:start position:0% +most before they find it so they're +going to spend the most time doing that + + align:start position:0% +going to spend the most time doing that + + + align:start position:0% +going to spend the most time doing that +and then when when they see them they + + align:start position:0% +and then when when they see them they + + + align:start position:0% +and then when when they see them they +have to stalk them and they're going to + + align:start position:0% +have to stalk them and they're going to + + + align:start position:0% +have to stalk them and they're going to +do that a lot more than they will + + align:start position:0% +do that a lot more than they will + + + align:start position:0% +do that a lot more than they will +actually pounce because they don't get + + align:start position:0% +actually pounce because they don't get + + + align:start position:0% +actually pounce because they don't get +the opportunity to pounce that often + + align:start position:0% +the opportunity to pounce that often + + + align:start position:0% +the opportunity to pounce that often +okay the animals move away the animals + + align:start position:0% +okay the animals move away the animals + + + align:start position:0% +okay the animals move away the animals +smell them and run away and so + + align:start position:0% + + + + align:start position:0% + +forth and of course the The Killing bite + + align:start position:0% +forth and of course the The Killing bite + + + align:start position:0% +forth and of course the The Killing bite +is executed the least + + align:start position:0% +is executed the least + + + align:start position:0% +is executed the least +frequently because sometimes when they + + align:start position:0% +frequently because sometimes when they + + + align:start position:0% +frequently because sometimes when they +pounce on an animal the animal still + + align:start position:0% +pounce on an animal the animal still + + + align:start position:0% +pounce on an animal the animal still +escapes we talk about Escape Behavior + + align:start position:0% +escapes we talk about Escape Behavior + + + align:start position:0% +escapes we talk about Escape Behavior +you'll see examples of that on + + align:start position:0% +you'll see examples of that on + + + align:start position:0% +you'll see examples of that on +videos so that's the action that's done + + align:start position:0% +videos so that's the action that's done + + + align:start position:0% +videos so that's the action that's done +the + + align:start position:0% +the + + + align:start position:0% +the +least well that means that the action + + align:start position:0% +least well that means that the action + + + align:start position:0% +least well that means that the action +specific potential the motivation to do + + align:start position:0% +specific potential the motivation to do + + + align:start position:0% +specific potential the motivation to do +those different things building up at a + + align:start position:0% +those different things building up at a + + + align:start position:0% +those different things building up at a +different rate they're much more + + align:start position:0% +different rate they're much more + + + align:start position:0% +different rate they're much more +motivated to do searching + + align:start position:0% +motivated to do searching + + + align:start position:0% +motivated to do searching +Locomotion than they are those other + + align:start position:0% +Locomotion than they are those other + + + align:start position:0% +Locomotion than they are those other +things because they have to do it the + + align:start position:0% +things because they have to do it the + + + align:start position:0% +things because they have to do it the +most + + align:start position:0% +most + + + align:start position:0% +most +we'll come back to + + align:start position:0% +we'll come back to + + + align:start position:0% +we'll come back to +this but for those frequently used + + align:start position:0% +this but for those frequently used + + + align:start position:0% +this but for those frequently used +action + + align:start position:0% +action + + + align:start position:0% +action +patterns the uh thresholds can be + + align:start position:0% +patterns the uh thresholds can be + + + align:start position:0% +patterns the uh thresholds can be +lowered quite frequently take for + + align:start position:0% +lowered quite frequently take for + + + align:start position:0% +lowered quite frequently take for +example uh flying in a little rent say + + align:start position:0% +example uh flying in a little rent say + + + align:start position:0% +example uh flying in a little rent say +and compare it to flying in a + + align:start position:0% +and compare it to flying in a + + + align:start position:0% +and compare it to flying in a +goose you know that little Ren Can't + + align:start position:0% +goose you know that little Ren Can't + + + align:start position:0% +goose you know that little Ren Can't +Stop for more than a few seconds before + + align:start position:0% +Stop for more than a few seconds before + + + align:start position:0% +Stop for more than a few seconds before +he's flying + + align:start position:0% +he's flying + + + align:start position:0% +he's flying +again they they flit + + align:start position:0% + + + + align:start position:0% + +around very + + align:start position:0% +around very + + + align:start position:0% +around very +frequently whereas the goose once he + + align:start position:0% + + + + align:start position:0% + +flies I don't want to mute it I just + + align:start position:0% +flies I don't want to mute it I just + + + align:start position:0% +flies I don't want to mute it I just +want to turn the amplitude down but this + + align:start position:0% +want to turn the amplitude down but this + + + align:start position:0% +want to turn the amplitude down but this +isn't + + align:start position:0% +isn't + + + align:start position:0% +isn't +there we + + align:start position:0% + + + + align:start position:0% + +go okay so the goose when he flies he + + align:start position:0% +go okay so the goose when he flies he + + + align:start position:0% +go okay so the goose when he flies he +won't fly again for quite a while unless + + align:start position:0% +won't fly again for quite a while unless + + + align:start position:0% +won't fly again for quite a while unless +a stimulus like a predator you know + + align:start position:0% +a stimulus like a predator you know + + + align:start position:0% +a stimulus like a predator you know +causes a rapid rise in the motivation to + + align:start position:0% +causes a rapid rise in the motivation to + + + align:start position:0% +causes a rapid rise in the motivation to +fly but in most cases uh if he's not + + align:start position:0% +fly but in most cases uh if he's not + + + align:start position:0% +fly but in most cases uh if he's not +being disturbed by Predators he won't + + align:start position:0% +being disturbed by Predators he won't + + + align:start position:0% +being disturbed by Predators he won't +fly again for quite a while whereas the + + align:start position:0% +fly again for quite a while whereas the + + + align:start position:0% +fly again for quite a while whereas the +ren is flying much more so the the rate + + align:start position:0% +ren is flying much more so the the rate + + + align:start position:0% +ren is flying much more so the the rate +of build up is different from species to + + align:start position:0% +of build up is different from species to + + + align:start position:0% +of build up is different from species to +species for the very same action pattern + + align:start position:0% +species for the very same action pattern + + + align:start position:0% +species for the very same action pattern +and it's different for different fixed + + align:start position:0% +and it's different for different fixed + + + align:start position:0% +and it's different for different fixed +action patterns in the same + + align:start position:0% + + + + align:start position:0% + +species let's talk about the + + align:start position:0% + + + + align:start position:0% + +threshold for this responding to stimuli + + align:start position:0% +threshold for this responding to stimuli + + + align:start position:0% +threshold for this responding to stimuli +that elicit a fixed action + + align:start position:0% +that elicit a fixed action + + + align:start position:0% +that elicit a fixed action +pattern as the motivation builds up the + + align:start position:0% +pattern as the motivation builds up the + + + align:start position:0% +pattern as the motivation builds up the +threshold + + align:start position:0% + + + + align:start position:0% + +the amount of stimulation + + align:start position:0% +the amount of stimulation + + + align:start position:0% +the amount of stimulation +needed to get the action + + align:start position:0% +needed to get the action + + + align:start position:0% +needed to get the action +pattern that uh goes + + align:start position:0% +pattern that uh goes + + + align:start position:0% +pattern that uh goes +down look at hunger and feeding we've + + align:start position:0% +down look at hunger and feeding we've + + + align:start position:0% +down look at hunger and feeding we've +mentioned this before and it's obvious + + align:start position:0% +mentioned this before and it's obvious + + + align:start position:0% +mentioned this before and it's obvious +when you think about it when the + + align:start position:0% +when you think about it when the + + + align:start position:0% +when you think about it when the +hungrier the animal or person + + align:start position:0% +hungrier the animal or person + + + align:start position:0% +hungrier the animal or person +is the less discriminating he is why do + + align:start position:0% +is the less discriminating he is why do + + + align:start position:0% +is the less discriminating he is why do +we have dessert at the end of a meal + + align:start position:0% +we have dessert at the end of a meal + + + align:start position:0% +we have dessert at the end of a meal +we're not as + + align:start position:0% +we're not as + + + align:start position:0% +we're not as +hungry so it's often the most palatable + + align:start position:0% +hungry so it's often the most palatable + + + align:start position:0% +hungry so it's often the most palatable +thing of course there are exceptions but + + align:start position:0% +thing of course there are exceptions but + + + align:start position:0% +thing of course there are exceptions but +most of us like sweet + + align:start position:0% +most of us like sweet + + + align:start position:0% +most of us like sweet +things some countries don't even serve + + align:start position:0% +things some countries don't even serve + + + align:start position:0% +things some countries don't even serve +theer like in China an American + + align:start position:0% +theer like in China an American + + + align:start position:0% +theer like in China an American +habit okay but of course it occurs in in + + align:start position:0% +habit okay but of course it occurs in in + + + align:start position:0% +habit okay but of course it occurs in in +many countries that have it the dessert + + align:start position:0% +many countries that have it the dessert + + + align:start position:0% +many countries that have it the dessert +is last because it's the most palatable + + align:start position:0% +is last because it's the most palatable + + + align:start position:0% +is last because it's the most palatable +thing and uh they they will still eat + + align:start position:0% +thing and uh they they will still eat + + + align:start position:0% +thing and uh they they will still eat +dessert even though they're not hungry + + align:start position:0% +dessert even though they're not hungry + + + align:start position:0% +dessert even though they're not hungry +for food other Foods + + align:start position:0% +for food other Foods + + + align:start position:0% +for food other Foods +anymore and as I mentioned if you have a + + align:start position:0% +anymore and as I mentioned if you have a + + + align:start position:0% +anymore and as I mentioned if you have a +child that's very finicky that's because + + align:start position:0% +child that's very finicky that's because + + + align:start position:0% +child that's very finicky that's because +he's still + + align:start position:0% +he's still + + + align:start position:0% +he's still +welled much less finicky if he's + + align:start position:0% + + + + align:start position:0% + +hungry and if you don't like certain and + + align:start position:0% +hungry and if you don't like certain and + + + align:start position:0% +hungry and if you don't like certain and +certain something and all your friends + + align:start position:0% +certain something and all your friends + + + align:start position:0% +certain something and all your friends +do like it well just don't eat for a + + align:start position:0% +do like it well just don't eat for a + + + align:start position:0% +do like it well just don't eat for a +while if you want to start liking + + align:start position:0% +while if you want to start liking + + + align:start position:0% +while if you want to start liking +it and then you'll get used to + + align:start position:0% +it and then you'll get used to + + + align:start position:0% +it and then you'll get used to +it + + align:start position:0% + + + + align:start position:0% + +I thought I'd never like beer I hated + + align:start position:0% +I thought I'd never like beer I hated + + + align:start position:0% +I thought I'd never like beer I hated +beer when I was a kid brother would be + + align:start position:0% +beer when I was a kid brother would be + + + align:start position:0% +beer when I was a kid brother would be +drinking beer + + align:start position:0% +drinking beer + + + align:start position:0% +drinking beer +couldn't stand the stuff but then on a + + align:start position:0% +couldn't stand the stuff but then on a + + + align:start position:0% +couldn't stand the stuff but then on a +real hot day you get really + + align:start position:0% +real hot day you get really + + + align:start position:0% +real hot day you get really +thirsty and your much your thresholds + + align:start position:0% +thirsty and your much your thresholds + + + align:start position:0% +thirsty and your much your thresholds +are lowered okay your thresholds for + + align:start position:0% +are lowered okay your thresholds for + + + align:start position:0% +are lowered okay your thresholds for +drinking and so you like it a little + + align:start position:0% +drinking and so you like it a little + + + align:start position:0% +drinking and so you like it a little +better and then I got used to it now I + + align:start position:0% +better and then I got used to it now I + + + align:start position:0% +better and then I got used to it now I +can drink beer still don't like it as + + align:start position:0% +can drink beer still don't like it as + + + align:start position:0% +can drink beer still don't like it as +well as some people people do + + align:start position:0% + + + + align:start position:0% + +okay breeding sexual attraction really + + align:start position:0% +okay breeding sexual attraction really + + + align:start position:0% +okay breeding sexual attraction really +obvious a horse breeder if he wants his + + align:start position:0% +obvious a horse breeder if he wants his + + + align:start position:0% +obvious a horse breeder if he wants his +Mar if he he's got a stallion let's say + + align:start position:0% +Mar if he he's got a stallion let's say + + + align:start position:0% +Mar if he he's got a stallion let's say +and + + align:start position:0% +and + + + align:start position:0% +and +he's wants to breed that stallion if the + + align:start position:0% +he's wants to breed that stallion if the + + + align:start position:0% +he's wants to breed that stallion if the +stallion is worth a lot he gets money + + align:start position:0% +stallion is worth a lot he gets money + + + align:start position:0% +stallion is worth a lot he gets money +for + + align:start position:0% +for + + + align:start position:0% +for +that but if he's being paid that + + align:start position:0% +that but if he's being paid that + + + align:start position:0% +that but if he's being paid that +stallion has to perform so what does he + + align:start position:0% +stallion has to perform so what does he + + + align:start position:0% +stallion has to perform so what does he +do he he does not let that stallion + + align:start position:0% +do he he does not let that stallion + + + align:start position:0% +do he he does not let that stallion +copulate for a long period of time so he + + align:start position:0% +copulate for a long period of time so he + + + align:start position:0% +copulate for a long period of time so he +the + + align:start position:0% +the + + + align:start position:0% +the +motivation to breed builds up in the + + align:start position:0% +motivation to breed builds up in the + + + align:start position:0% +motivation to breed builds up in the +animal and if you build it up enough I + + align:start position:0% +animal and if you build it up enough I + + + align:start position:0% +animal and if you build it up enough I +mean he'll breed with a + + align:start position:0% +mean he'll breed with a + + + align:start position:0% +mean he'll breed with a +mule that's how you get + + align:start position:0% +mule that's how you get + + + align:start position:0% +mule that's how you get +donkeys and and so that's important and + + align:start position:0% +donkeys and and so that's important and + + + align:start position:0% +donkeys and and so that's important and +it happens in humans too there's an + + align:start position:0% +it happens in humans too there's an + + + align:start position:0% +it happens in humans too there's an +amusing story there in the Lawrence + + align:start position:0% +amusing story there in the Lawrence + + + align:start position:0% +amusing story there in the Lawrence +reading about story told to Lawrence by + + align:start position:0% +reading about story told to Lawrence by + + + align:start position:0% +reading about story told to Lawrence by +a ship captain he knew and how he felt + + align:start position:0% +a ship captain he knew and how he felt + + + align:start position:0% +a ship captain he knew and how he felt +after being at sea for a long time he + + align:start position:0% +after being at sea for a long time he + + + align:start position:0% +after being at sea for a long time he +came back and he said every woman in + + align:start position:0% +came back and he said every woman in + + + align:start position:0% +came back and he said every woman in +town looks like hell on of + + align:start position:0% +town looks like hell on of + + + align:start position:0% +town looks like hell on of +TR but after I'd been here a couple + + align:start position:0% +TR but after I'd been here a couple + + + align:start position:0% +TR but after I'd been here a couple +weeks he said so many ugly + + align:start position:0% +weeks he said so many ugly + + + align:start position:0% +weeks he said so many ugly +ones What's happen threshold + + align:start position:0% +ones What's happen threshold + + + align:start position:0% +ones What's happen threshold +Loring okay + + align:start position:0% +Loring okay + + + align:start position:0% +Loring okay +so and this really explains to a large + + align:start position:0% +so and this really explains to a large + + + align:start position:0% +so and this really explains to a large +degree the phenomenon we + + align:start position:0% +degree the phenomenon we + + + align:start position:0% +degree the phenomenon we +call INB back + + align:start position:0% +call INB back + + + align:start position:0% +call INB back +reaction vacuum activity another term + + align:start position:0% +reaction vacuum activity another term + + + align:start position:0% +reaction vacuum activity another term +used in + + align:start position:0% +used in + + + align:start position:0% +used in +ethology it literally + + align:start position:0% +ethology it literally + + + align:start position:0% +ethology it literally +means when an instinctive Behavior + + align:start position:0% +means when an instinctive Behavior + + + align:start position:0% +means when an instinctive Behavior +pattern that occurs without any stimulus + + align:start position:0% +pattern that occurs without any stimulus + + + align:start position:0% +pattern that occurs without any stimulus +that would that would be the literal + + align:start position:0% +that would that would be the literal + + + align:start position:0% +that would that would be the literal +meaning of vacuum + + align:start position:0% +meaning of vacuum + + + align:start position:0% +meaning of vacuum +activity but in that in fact it seems to + + align:start position:0% +activity but in that in fact it seems to + + + align:start position:0% +activity but in that in fact it seems to +be a case of extreme threshold + + align:start position:0% +be a case of extreme threshold + + + align:start position:0% +be a case of extreme threshold +lowering the thresholds can get so low + + align:start position:0% +lowering the thresholds can get so low + + + align:start position:0% +lowering the thresholds can get so low +that we don't even notice the stimuli + + align:start position:0% +that we don't even notice the stimuli + + + align:start position:0% +that we don't even notice the stimuli +the animals are responding to and + + align:start position:0% +the animals are responding to and + + + align:start position:0% +the animals are responding to and +Lawrence talks about his when he was + + align:start position:0% +Lawrence talks about his when he was + + + align:start position:0% +Lawrence talks about his when he was +young he had a pet + + align:start position:0% +young he had a pet + + + align:start position:0% +young he had a pet +Starling and uh he could be eating + + align:start position:0% +Starling and uh he could be eating + + + align:start position:0% +Starling and uh he could be eating +dinner with his family and uh that he + + align:start position:0% +dinner with his family and uh that he + + + align:start position:0% +dinner with his family and uh that he +would notice that the Starling seemed to + + align:start position:0% +would notice that the Starling seemed to + + + align:start position:0% +would notice that the Starling seemed to +be catching and feeding on flies up near + + align:start position:0% +be catching and feeding on flies up near + + + align:start position:0% +be catching and feeding on flies up near +the + + align:start position:0% +the + + + align:start position:0% +the +ceiling and he couldn't see the Flies so + + align:start position:0% +ceiling and he couldn't see the Flies so + + + align:start position:0% +ceiling and he couldn't see the Flies so +he tried getting a ladder and going up + + align:start position:0% +he tried getting a ladder and going up + + + align:start position:0% +he tried getting a ladder and going up +there to see if we're in flies and he + + align:start position:0% +there to see if we're in flies and he + + + align:start position:0% +there to see if we're in flies and he +convinced himself that there were none + + align:start position:0% +convinced himself that there were none + + + align:start position:0% +convinced himself that there were none +you know and yet the Starling was there + + align:start position:0% +you know and yet the Starling was there + + + align:start position:0% +you know and yet the Starling was there +showing the fixed action pattern of + + align:start position:0% +showing the fixed action pattern of + + + align:start position:0% +showing the fixed action pattern of +searching for catching and and eating + + align:start position:0% +searching for catching and and eating + + + align:start position:0% +searching for catching and and eating +the + + align:start position:0% +the + + + align:start position:0% +the +Flies so that's called invacuo + + align:start position:0% +Flies so that's called invacuo + + + align:start position:0% +Flies so that's called invacuo +activity or + + align:start position:0% + + + + align:start position:0% + +reactions uh some of you that if you + + align:start position:0% +reactions uh some of you that if you + + + align:start position:0% +reactions uh some of you that if you +keep rats uh or mice and cages and they + + align:start position:0% +keep rats uh or mice and cages and they + + + align:start position:0% +keep rats uh or mice and cages and they +don't have any nesting material they + + align:start position:0% +don't have any nesting material they + + + align:start position:0% +don't have any nesting material they +have a motivation to nest and if they're + + align:start position:0% +have a motivation to nest and if they're + + + align:start position:0% +have a motivation to nest and if they're +deprived of nesting material for a long + + align:start position:0% +deprived of nesting material for a long + + + align:start position:0% +deprived of nesting material for a long +period of time they'll try to build a + + align:start position:0% +period of time they'll try to build a + + + align:start position:0% +period of time they'll try to build a +nest with their own tail you know + + align:start position:0% +nest with their own tail you know + + + align:start position:0% +nest with their own tail you know +and canaries will + + align:start position:0% +and canaries will + + + align:start position:0% +and canaries will +do build nests with their own + + align:start position:0% +do build nests with their own + + + align:start position:0% +do build nests with their own +feathers and + + align:start position:0% +feathers and + + + align:start position:0% +feathers and +uh male or Drakes when they're in + + align:start position:0% +uh male or Drakes when they're in + + + align:start position:0% +uh male or Drakes when they're in +a their highly + + align:start position:0% +a their highly + + + align:start position:0% +a their highly +motivated uh to mate they're also very + + align:start position:0% +motivated uh to mate they're also very + + + align:start position:0% +motivated uh to mate they're also very +aggressive against other males and they + + align:start position:0% + + + + align:start position:0% + +uh they'll actually attack their own + + align:start position:0% +uh they'll actually attack their own + + + align:start position:0% +uh they'll actually attack their own +Tails because the thresholds are so low + + align:start position:0% +Tails because the thresholds are so low + + + align:start position:0% +Tails because the thresholds are so low +it doesn't take much of a + + align:start position:0% +it doesn't take much of a + + + align:start position:0% +it doesn't take much of a +stimulus you know they just need certain + + align:start position:0% +stimulus you know they just need certain + + + align:start position:0% +stimulus you know they just need certain +key + + align:start position:0% +key + + + align:start position:0% +key +stimuli and if thresholds are low enough + + align:start position:0% +stimuli and if thresholds are low enough + + + align:start position:0% +stimuli and if thresholds are low enough +their own tail will be enough to elicit + + align:start position:0% +their own tail will be enough to elicit + + + align:start position:0% +their own tail will be enough to elicit +the behavior ostriches deprived of their + + align:start position:0% +the behavior ostriches deprived of their + + + align:start position:0% +the behavior ostriches deprived of their +usual method of feeding + + align:start position:0% +usual method of feeding + + + align:start position:0% +usual method of feeding +of grass they will pluck grass that is + + align:start position:0% +of grass they will pluck grass that is + + + align:start position:0% +of grass they will pluck grass that is +not not even + + align:start position:0% +not not even + + + align:start position:0% +not not even +there the same true is you will notice + + align:start position:0% +there the same true is you will notice + + + align:start position:0% +there the same true is you will notice +this in rodents if you don't you know we + + align:start position:0% +this in rodents if you don't you know we + + + align:start position:0% +this in rodents if you don't you know we +give them Road uh Rat pellets we call + + align:start position:0% +give them Road uh Rat pellets we call + + + align:start position:0% +give them Road uh Rat pellets we call +them well why do we give them food + + align:start position:0% +them well why do we give them food + + + align:start position:0% +them well why do we give them food +that's so + + align:start position:0% +that's so + + + align:start position:0% +that's so +hard in fact it's mixed with material + + align:start position:0% +hard in fact it's mixed with material + + + align:start position:0% +hard in fact it's mixed with material +that grinds their teeth down well they + + align:start position:0% +that grinds their teeth down well they + + + align:start position:0% +that grinds their teeth down well they +have to because in the case of rodents + + align:start position:0% +have to because in the case of rodents + + + align:start position:0% +have to because in the case of rodents +the teeth keep growing these Insider + + align:start position:0% +the teeth keep growing these Insider + + + align:start position:0% +the teeth keep growing these Insider +teeth on both bottom and top same is + + align:start position:0% +teeth on both bottom and top same is + + + align:start position:0% +teeth on both bottom and top same is +true of hamsters and mice they just keep + + align:start position:0% +true of hamsters and mice they just keep + + + align:start position:0% +true of hamsters and mice they just keep +growing so they're highly motivated to + + align:start position:0% +growing so they're highly motivated to + + + align:start position:0% +growing so they're highly motivated to +GW and if you deprive them of things to + + align:start position:0% +GW and if you deprive them of things to + + + align:start position:0% +GW and if you deprive them of things to +GW on let's say say you're feeding them + + align:start position:0% +GW on let's say say you're feeding them + + + align:start position:0% +GW on let's say say you're feeding them +wet Mash or something they can't wear + + align:start position:0% +wet Mash or something they can't wear + + + align:start position:0% +wet Mash or something they can't wear +their teeth down they will chew on the + + align:start position:0% +their teeth down they will chew on the + + + align:start position:0% +their teeth down they will chew on the +on the metal cage you know they'll chew + + align:start position:0% +on the metal cage you know they'll chew + + + align:start position:0% +on the metal cage you know they'll chew +on anything they can get their teeth + + align:start position:0% +on anything they can get their teeth + + + align:start position:0% +on anything they can get their teeth +around reminds me of some dogs + + align:start position:0% +around reminds me of some dogs + + + align:start position:0% +around reminds me of some dogs +I I don't know what their fixed action + + align:start position:0% +I I don't know what their fixed action + + + align:start position:0% +I I don't know what their fixed action +patterns how much of it's nesting or + + align:start position:0% +patterns how much of it's nesting or + + + align:start position:0% +patterns how much of it's nesting or +whatever but some dogs also can mess up + + align:start position:0% +whatever but some dogs also can mess up + + + align:start position:0% +whatever but some dogs also can mess up +your house quite a bit because of what + + align:start position:0% +your house quite a bit because of what + + + align:start position:0% +your house quite a bit because of what +they do to to shoes blankets and so + + align:start position:0% +they do to to shoes blankets and so + + + align:start position:0% +they do to to shoes blankets and so +forth so with a lot of thresold lowering + + align:start position:0% +forth so with a lot of thresold lowering + + + align:start position:0% +forth so with a lot of thresold lowering +you all all you need is a very small + + align:start position:0% +you all all you need is a very small + + + align:start position:0% +you all all you need is a very small +stimulus it's it's almost like an + + align:start position:0% +stimulus it's it's almost like an + + + align:start position:0% +stimulus it's it's almost like an +internal + + align:start position:0% +internal + + + align:start position:0% +internal +Reservoir um that's sort of a metaphor + + align:start position:0% +Reservoir um that's sort of a metaphor + + + align:start position:0% +Reservoir um that's sort of a metaphor +for the the action specific potential + + align:start position:0% +for the the action specific potential + + + align:start position:0% +for the the action specific potential +builds up to a point it just starts + + align:start position:0% +builds up to a point it just starts + + + align:start position:0% +builds up to a point it just starts +spilling + + align:start position:0% + + + + align:start position:0% + +over now we talked last time about the + + align:start position:0% +over now we talked last time about the + + + align:start position:0% +over now we talked last time about the +different components of fixed action + + align:start position:0% +different components of fixed action + + + align:start position:0% +different components of fixed action +patterns and we'll use these terms a + + align:start position:0% +patterns and we'll use these terms a + + + align:start position:0% +patterns and we'll use these terms a +lot uh there was a component that wasn't + + align:start position:0% +lot uh there was a component that wasn't + + + align:start position:0% +lot uh there was a component that wasn't +defined for a long time until the + + align:start position:0% +defined for a long time until the + + + align:start position:0% +defined for a long time until the +skywall Craig uh defined it it + + align:start position:0% +skywall Craig uh defined it it + + + align:start position:0% +skywall Craig uh defined it it +corresponds to the level of uh + + align:start position:0% +corresponds to the level of uh + + + align:start position:0% +corresponds to the level of uh +the action specific potential but before + + align:start position:0% +the action specific potential but before + + + align:start position:0% +the action specific potential but before +they even use that theoretical term this + + align:start position:0% +they even use that theoretical term this + + + align:start position:0% +they even use that theoretical term this +Behavior had been described what is it + + align:start position:0% +Behavior had been described what is it + + + align:start position:0% +Behavior had been described what is it +what did Craig talk + + align:start position:0% +what did Craig talk + + + align:start position:0% +what did Craig talk +about appetitive Behavior It's usually + + align:start position:0% +about appetitive Behavior It's usually + + + align:start position:0% +about appetitive Behavior It's usually +the app appetitive behavior of some sort + + align:start position:0% +the app appetitive behavior of some sort + + + align:start position:0% +the app appetitive behavior of some sort +usually Locomotion and searching + + align:start position:0% +usually Locomotion and searching + + + align:start position:0% +usually Locomotion and searching +behavior and + + align:start position:0% +behavior and + + + align:start position:0% +behavior and +orienting is has the lowest threshold so + + align:start position:0% +orienting is has the lowest threshold so + + + align:start position:0% +orienting is has the lowest threshold so +when an animal gets hungry he the the + + align:start position:0% +when an animal gets hungry he the the + + + align:start position:0% +when an animal gets hungry he the the +action the the the movement that's part + + align:start position:0% +action the the the movement that's part + + + align:start position:0% +action the the the movement that's part +of the the series of actions that + + align:start position:0% +of the the series of actions that + + + align:start position:0% +of the the series of actions that +compose a fixed action + + align:start position:0% +compose a fixed action + + + align:start position:0% +compose a fixed action +pattern the part with the lowest + + align:start position:0% +pattern the part with the lowest + + + align:start position:0% +pattern the part with the lowest +threshold is repetitive Behavior + + align:start position:0% +threshold is repetitive Behavior + + + align:start position:0% +threshold is repetitive Behavior +searching Behavior so they literally + + align:start position:0% +searching Behavior so they literally + + + align:start position:0% +searching Behavior so they literally +search for the stimulus that will lead + + align:start position:0% +search for the stimulus that will lead + + + align:start position:0% +search for the stimulus that will lead +to the rest of the + + align:start position:0% + + + + align:start position:0% + +behavior + + align:start position:0% +behavior + + + align:start position:0% +behavior +and finding appetitive behavior for + + align:start position:0% +and finding appetitive behavior for + + + align:start position:0% +and finding appetitive behavior for +some fix action patterns especially in + + align:start position:0% +some fix action patterns especially in + + + align:start position:0% +some fix action patterns especially in +humans has been led to quite a bit of + + align:start position:0% +humans has been led to quite a bit of + + + align:start position:0% +humans has been led to quite a bit of +controversy and the controversy that + + align:start position:0% +controversy and the controversy that + + + align:start position:0% +controversy and the controversy that +Lawrence got into + + align:start position:0% +Lawrence got into + + + align:start position:0% +Lawrence got into +concerned what he called an appetite for + + align:start position:0% + + + + align:start position:0% + +aggression for example the second one + + align:start position:0% +aggression for example the second one + + + align:start position:0% +aggression for example the second one +the grayle gander you know when he's in + + align:start position:0% +the grayle gander you know when he's in + + + align:start position:0% +the grayle gander you know when he's in +an aggressive mood because he's in the + + align:start position:0% +an aggressive mood because he's in the + + + align:start position:0% +an aggressive mood because he's in the +mating mood + + align:start position:0% +mating mood + + + align:start position:0% +mating mood +uh he literally looks for other + + align:start position:0% +uh he literally looks for other + + + align:start position:0% +uh he literally looks for other +ganders to fight with okay and there's + + align:start position:0% +ganders to fight with okay and there's + + + align:start position:0% +ganders to fight with okay and there's +other many many animals are like this + + align:start position:0% +other many many animals are like this + + + align:start position:0% +other many many animals are like this +and so he applied this to humans he said + + align:start position:0% +and so he applied this to humans he said + + + align:start position:0% +and so he applied this to humans he said +think of the young men roam the streets + + align:start position:0% +think of the young men roam the streets + + + align:start position:0% +think of the young men roam the streets +looking for trouble what are they doing + + align:start position:0% +looking for trouble what are they doing + + + align:start position:0% +looking for trouble what are they doing +it's the same thing they have a + + align:start position:0% +it's the same thing they have a + + + align:start position:0% +it's the same thing they have a +motivation to get into + + align:start position:0% +motivation to get into + + + align:start position:0% +motivation to get into +fights maybe maybe our aggressive video + + align:start position:0% +fights maybe maybe our aggressive video + + + align:start position:0% +fights maybe maybe our aggressive video +games are able to satisfy that urge for + + align:start position:0% +games are able to satisfy that urge for + + + align:start position:0% +games are able to satisfy that urge for +most of a lot of young men but if you + + align:start position:0% +most of a lot of young men but if you + + + align:start position:0% +most of a lot of young men but if you +look at aggressive video games and see + + align:start position:0% +look at aggressive video games and see + + + align:start position:0% +look at aggressive video games and see +who plays them you'll see it's much more + + align:start position:0% +who plays them you'll see it's much more + + + align:start position:0% +who plays them you'll see it's much more +males than females so there are girls + + align:start position:0% +males than females so there are girls + + + align:start position:0% +males than females so there are girls +that do it + + align:start position:0% +that do it + + + align:start position:0% +that do it +too and uh young men that seem to have + + align:start position:0% +too and uh young men that seem to have + + + align:start position:0% +too and uh young men that seem to have +no real desire to fight at all can get + + align:start position:0% +no real desire to fight at all can get + + + align:start position:0% +no real desire to fight at all can get +extremely involved in these games and + + align:start position:0% +extremely involved in these games and + + + align:start position:0% +extremely involved in these games and +they can feel great Triumph when they + + align:start position:0% +they can feel great Triumph when they + + + align:start position:0% +they can feel great Triumph when they +win I remember when my son was growing + + align:start position:0% +win I remember when my son was growing + + + align:start position:0% +win I remember when my son was growing +up uh this was long before he came came + + align:start position:0% +up uh this was long before he came came + + + align:start position:0% +up uh this was long before he came came +to MIT uh he went to the MIT camp and + + align:start position:0% +to MIT uh he went to the MIT camp and + + + align:start position:0% +to MIT uh he went to the MIT camp and +the counselor found out that all the + + align:start position:0% +the counselor found out that all the + + + align:start position:0% +the counselor found out that all the +young men in his group uh were mostly + + align:start position:0% +young men in his group uh were mostly + + + align:start position:0% +young men in his group uh were mostly +Middle School age they love this + + align:start position:0% +Middle School age they love this + + + align:start position:0% +Middle School age they love this +particular video game that he also + + align:start position:0% +particular video game that he also + + + align:start position:0% +particular video game that he also +played it's like many many MIT students + + align:start position:0% +played it's like many many MIT students + + + align:start position:0% +played it's like many many MIT students +so he organized the tournament and the + + align:start position:0% +so he organized the tournament and the + + + align:start position:0% +so he organized the tournament and the +kids got go involved in it you know and + + align:start position:0% +kids got go involved in it you know and + + + align:start position:0% +kids got go involved in it you know and +my son I could tell he's not aggressive + + align:start position:0% +my son I could tell he's not aggressive + + + align:start position:0% +my son I could tell he's not aggressive +but he felt great great Triumph when he + + align:start position:0% +but he felt great great Triumph when he + + + align:start position:0% +but he felt great great Triumph when he +beat the counselor in the first part of + + align:start position:0% +beat the counselor in the first part of + + + align:start position:0% +beat the counselor in the first part of +the tournament of course they continued + + align:start position:0% +the tournament of course they continued + + + align:start position:0% +the tournament of course they continued +the tournament and the counselor beat + + align:start position:0% +the tournament and the counselor beat + + + align:start position:0% +the tournament and the counselor beat +him the second time but you could tell + + align:start position:0% +him the second time but you could tell + + + align:start position:0% +him the second time but you could tell +that he had that a + + align:start position:0% +that he had that a + + + align:start position:0% +that he had that a +drive that was this all happened after + + align:start position:0% +drive that was this all happened after + + + align:start position:0% +drive that was this all happened after +Lawrence of course had done his studies + + align:start position:0% +Lawrence of course had done his studies + + + align:start position:0% +Lawrence of course had done his studies +I don't know what he would say + + align:start position:0% +I don't know what he would say + + + align:start position:0% +I don't know what he would say +about the motivation behind doing these + + align:start position:0% +about the motivation behind doing these + + + align:start position:0% +about the motivation behind doing these +video games but I'm sure what I'm saying + + align:start position:0% +video games but I'm sure what I'm saying + + + align:start position:0% +video games but I'm sure what I'm saying +is some part of the explanation many + + align:start position:0% +is some part of the explanation many + + + align:start position:0% +is some part of the explanation many +experiments done with Jewel fish because + + align:start position:0% +experiments done with Jewel fish because + + + align:start position:0% +experiments done with Jewel fish because +of their fighting behavior and one in + + align:start position:0% +of their fighting behavior and one in + + + align:start position:0% +of their fighting behavior and one in +one of the + + align:start position:0% +one of the + + + align:start position:0% +one of the +experiments male Jewish jewfish that + + align:start position:0% +experiments male Jewish jewfish that + + + align:start position:0% +experiments male Jewish jewfish that +wanted to fight he would could teach + + align:start position:0% +wanted to fight he would could teach + + + align:start position:0% +wanted to fight he would could teach +them a maaz when the only reward was + + align:start position:0% +them a maaz when the only reward was + + + align:start position:0% +them a maaz when the only reward was +getting a a visual view of another Jewel + + align:start position:0% +getting a a visual view of another Jewel + + + align:start position:0% +getting a a visual view of another Jewel +a male Jew Jewel fish also in the + + align:start position:0% +a male Jew Jewel fish also in the + + + align:start position:0% +a male Jew Jewel fish also in the +fighting they change coloration when + + align:start position:0% +fighting they change coloration when + + + align:start position:0% +fighting they change coloration when +they're in that mood and uh just seeing + + align:start position:0% +they're in that mood and uh just seeing + + + align:start position:0% +they're in that mood and uh just seeing +the other male and being able to attack + + align:start position:0% +the other male and being able to attack + + + align:start position:0% +the other male and being able to attack +the glass see they they didn't actually + + align:start position:0% +the glass see they they didn't actually + + + align:start position:0% +the glass see they they didn't actually +fight you didn't need to get them to + + align:start position:0% +fight you didn't need to get them to + + + align:start position:0% +fight you didn't need to get them to +fight to to get that reward and so it + + align:start position:0% +fight to to get that reward and so it + + + align:start position:0% +fight to to get that reward and so it +might seem strange to you but being + + align:start position:0% +might seem strange to you but being + + + align:start position:0% +might seem strange to you but being +hungry can is necessary to be rewarded + + align:start position:0% +hungry can is necessary to be rewarded + + + align:start position:0% +hungry can is necessary to be rewarded +by truth so actually we like to be + + align:start position:0% +by truth so actually we like to be + + + align:start position:0% +by truth so actually we like to be +hungry just not too + + align:start position:0% +hungry just not too + + + align:start position:0% +hungry just not too +hungry okay + + align:start position:0% +hungry okay + + + align:start position:0% +hungry okay +because without being hungry food isn't + + align:start position:0% +because without being hungry food isn't + + + align:start position:0% +because without being hungry food isn't +rewarding and it's the same for the + + align:start position:0% +rewarding and it's the same for the + + + align:start position:0% +rewarding and it's the same for the +aggressive + + align:start position:0% + + + + align:start position:0% + +dve so I just discussed briefly here the + + align:start position:0% +dve so I just discussed briefly here the + + + align:start position:0% +dve so I just discussed briefly here the +reactions people have had against that + + align:start position:0% +reactions people have had against that + + + align:start position:0% +reactions people have had against that +remember for a long time uh especially + + align:start position:0% +remember for a long time uh especially + + + align:start position:0% +remember for a long time uh especially +in America and in Russia there was a + + align:start position:0% +in America and in Russia there was a + + + align:start position:0% +in America and in Russia there was a +pretty strong bias that against any + + align:start position:0% +pretty strong bias that against any + + + align:start position:0% +pretty strong bias that against any +behavior that couldn't be explained in + + align:start position:0% +behavior that couldn't be explained in + + + align:start position:0% +behavior that couldn't be explained in +terms of a stimulus response model you + + align:start position:0% +terms of a stimulus response model you + + + align:start position:0% +terms of a stimulus response model you +know people come to believe that a + + align:start position:0% +know people come to believe that a + + + align:start position:0% +know people come to believe that a +certain model is adequate to explain all + + align:start position:0% +certain model is adequate to explain all + + + align:start position:0% +certain model is adequate to explain all +Behavior they don't like it and there's + + align:start position:0% +Behavior they don't like it and there's + + + align:start position:0% +Behavior they don't like it and there's +some behavior that can't be explained so + + align:start position:0% +some behavior that can't be explained so + + + align:start position:0% +some behavior that can't be explained so +they're going to try to find some way to + + align:start position:0% +they're going to try to find some way to + + + align:start position:0% +they're going to try to find some way to +explain it + + align:start position:0% + + + + align:start position:0% + +away and uh so how could there be an + + align:start position:0% +away and uh so how could there be an + + + align:start position:0% +away and uh so how could there be an +appetite for aggression it has must be a + + align:start position:0% +appetite for aggression it has must be a + + + align:start position:0% +appetite for aggression it has must be a +stimulus and yes there's all they're + + align:start position:0% +stimulus and yes there's all they're + + + align:start position:0% +stimulus and yes there's all they're +always responding to some stimuli but + + align:start position:0% +always responding to some stimuli but + + + align:start position:0% +always responding to some stimuli but +the stimulus can be minimal and the + + align:start position:0% +the stimulus can be minimal and the + + + align:start position:0% +the stimulus can be minimal and the +thresholds can change drastically due to + + align:start position:0% +thresholds can change drastically due to + + + align:start position:0% +thresholds can change drastically due to +an internal State that's + + align:start position:0% +an internal State that's + + + align:start position:0% +an internal State that's +changing and of course we know there was + + align:start position:0% +changing and of course we know there was + + + align:start position:0% +changing and of course we know there was +a bias against instinctive behavior in + + align:start position:0% +a bias against instinctive behavior in + + + align:start position:0% +a bias against instinctive behavior in +general especially in humans but not + + align:start position:0% +general especially in humans but not + + + align:start position:0% +general especially in humans but not +only in humans they I I read studies in + + align:start position:0% +only in humans they I I read studies in + + + align:start position:0% +only in humans they I I read studies in +written in the 30s especially uh before + + align:start position:0% +written in the 30s especially uh before + + + align:start position:0% +written in the 30s especially uh before +World War II where people experimenters + + align:start position:0% +World War II where people experimenters + + + align:start position:0% +World War II where people experimenters +went to Great length to try to proed + + align:start position:0% +went to Great length to try to proed + + + align:start position:0% +went to Great length to try to proed +that some behavior that appeared seemed + + align:start position:0% +that some behavior that appeared seemed + + + align:start position:0% +that some behavior that appeared seemed +to have be innate because it appeared in + + align:start position:0% +to have be innate because it appeared in + + + align:start position:0% +to have be innate because it appeared in +very + + align:start position:0% +very + + + align:start position:0% +very +early uh was actually learned in + + align:start position:0% + + + + align:start position:0% + +utero it was believed that for example + + align:start position:0% +utero it was believed that for example + + + align:start position:0% +utero it was believed that for example +the the birds that have to Peck their + + align:start position:0% +the the birds that have to Peck their + + + align:start position:0% +the the birds that have to Peck their +way out of an egg they actually learned + + align:start position:0% +way out of an egg they actually learned + + + align:start position:0% +way out of an egg they actually learned +to do that in the uterus or in the egg + + align:start position:0% +to do that in the uterus or in the egg + + + align:start position:0% +to do that in the uterus or in the egg +before they were before they had and + + align:start position:0% +before they were before they had and + + + align:start position:0% +before they were before they had and +they went to Great length to show that + + align:start position:0% +they went to Great length to show that + + + align:start position:0% +they went to Great length to show that +there could be such + + align:start position:0% + + + + align:start position:0% + +experience now people are are not quite + + align:start position:0% +experience now people are are not quite + + + align:start position:0% +experience now people are are not quite +so + + align:start position:0% +so + + + align:start position:0% +so +extreme + + align:start position:0% +extreme + + + align:start position:0% +extreme +although there are still people in the + + align:start position:0% +although there are still people in the + + + align:start position:0% +although there are still people in the +humanities and even in + + align:start position:0% +humanities and even in + + + align:start position:0% +humanities and even in +sociology that believe that all that + + align:start position:0% +sociology that believe that all that + + + align:start position:0% +sociology that believe that all that +unlearn behavior is not important in + + align:start position:0% +unlearn behavior is not important in + + + align:start position:0% +unlearn behavior is not important in +explaining human + + align:start position:0% + + + + align:start position:0% + +behavior so let's go back to this topic + + align:start position:0% +behavior so let's go back to this topic + + + align:start position:0% +behavior so let's go back to this topic +of internal Readiness the action + + align:start position:0% +of internal Readiness the action + + + align:start position:0% +of internal Readiness the action +specific potential and how it varies + + align:start position:0% +specific potential and how it varies + + + align:start position:0% +specific potential and how it varies +just to give some + + align:start position:0% +just to give some + + + align:start position:0% +just to give some +examples I mentioned how flying builds + + align:start position:0% +examples I mentioned how flying builds + + + align:start position:0% +examples I mentioned how flying builds +up the different rates and different + + align:start position:0% +up the different rates and different + + + align:start position:0% +up the different rates and different +birds uh but take the example uh I think + + align:start position:0% +birds uh but take the example uh I think + + + align:start position:0% +birds uh but take the example uh I think +this is described in the Lawrence + + align:start position:0% +this is described in the Lawrence + + + align:start position:0% +this is described in the Lawrence +chapter uh from Paul leusen studies of + + align:start position:0% +chapter uh from Paul leusen studies of + + + align:start position:0% +chapter uh from Paul leusen studies of +cats leus studied a number of different + + align:start position:0% +cats leus studied a number of different + + + align:start position:0% +cats leus studied a number of different +species of cats uh found the same fix + + align:start position:0% +species of cats uh found the same fix + + + align:start position:0% +species of cats uh found the same fix +action patterns with slight variations + + align:start position:0% +action patterns with slight variations + + + align:start position:0% +action patterns with slight variations +of course in different species of cat + + align:start position:0% +of course in different species of cat + + + align:start position:0% +of course in different species of cat +including the very large Asian and + + align:start position:0% +including the very large Asian and + + + align:start position:0% +including the very large Asian and +African cats and domestic cats in + + align:start position:0% +African cats and domestic cats in + + + align:start position:0% +African cats and domestic cats in +America and Europe + + align:start position:0% + + + + align:start position:0% + +uh and if you have a cat that a hunter + + align:start position:0% +uh and if you have a cat that a hunter + + + align:start position:0% +uh and if you have a cat that a hunter +that is he's been exposed to hunting + + align:start position:0% +that is he's been exposed to hunting + + + align:start position:0% +that is he's been exposed to hunting +when he was he's watched his mother hunt + + align:start position:0% +when he was he's watched his mother hunt + + + align:start position:0% +when he was he's watched his mother hunt +he will become a hunter okay and if he's + + align:start position:0% +he will become a hunter okay and if he's + + + align:start position:0% +he will become a hunter okay and if he's +deprived of hunting for a long period + + align:start position:0% +deprived of hunting for a long period + + + align:start position:0% +deprived of hunting for a long period +what does that Cat do if you put him in + + align:start position:0% +what does that Cat do if you put him in + + + align:start position:0% +what does that Cat do if you put him in +a room full of + + align:start position:0% + + + + align:start position:0% + +mice well he he will initially attack + + align:start position:0% +mice well he he will initially attack + + + align:start position:0% +mice well he he will initially attack +and kill a few of those mice then what + + align:start position:0% +and kill a few of those mice then what + + + align:start position:0% +and kill a few of those mice then what +does he + + align:start position:0% +does he + + + align:start position:0% +does he +do does he just stop no he continues to + + align:start position:0% +do does he just stop no he continues to + + + align:start position:0% +do does he just stop no he continues to +stalk and pounce on mice but he stops + + align:start position:0% +stalk and pounce on mice but he stops + + + align:start position:0% +stalk and pounce on mice but he stops +executing the killing bite he will jump + + align:start position:0% +executing the killing bite he will jump + + + align:start position:0% +executing the killing bite he will jump +on them and SWAT them with his + + align:start position:0% +on them and SWAT them with his + + + align:start position:0% +on them and SWAT them with his +paws and it looks like he's playing with + + align:start position:0% +paws and it looks like he's playing with + + + align:start position:0% +paws and it looks like he's playing with +them and then eventually he will stalk + + align:start position:0% +them and then eventually he will stalk + + + align:start position:0% +them and then eventually he will stalk +them but he won't even + + align:start position:0% +them but he won't even + + + align:start position:0% +them but he won't even +p and then eventually he will just he + + align:start position:0% +p and then eventually he will just he + + + align:start position:0% +p and then eventually he will just he +appears to be searching for them he's + + align:start position:0% +appears to be searching for them he's + + + align:start position:0% +appears to be searching for them he's +very alert picks up his ears he's + + align:start position:0% +very alert picks up his ears he's + + + align:start position:0% +very alert picks up his ears he's +watching them he's showing all the + + align:start position:0% +watching them he's showing all the + + + align:start position:0% +watching them he's showing all the +orienting movements of a searching cat + + align:start position:0% +orienting movements of a searching cat + + + align:start position:0% +orienting movements of a searching cat +but now he's not doing any of those + + align:start position:0% +but now he's not doing any of those + + + align:start position:0% +but now he's not doing any of those +things and eventually ACC course he'll + + align:start position:0% +things and eventually ACC course he'll + + + align:start position:0% +things and eventually ACC course he'll +go to + + align:start position:0% +go to + + + align:start position:0% +go to +sleep so that because the the rate at + + align:start position:0% +sleep so that because the the rate at + + + align:start position:0% +sleep so that because the the rate at +which the action specific potential + + align:start position:0% +which the action specific potential + + + align:start position:0% +which the action specific potential +behind each of those fix action patterns + + align:start position:0% +behind each of those fix action patterns + + + align:start position:0% +behind each of those fix action patterns +that have been combined in attack + + align:start position:0% +that have been combined in attack + + + align:start position:0% +that have been combined in attack +behavior of the cat builds up at a + + align:start position:0% +behavior of the cat builds up at a + + + align:start position:0% +behavior of the cat builds up at a +different rate depending on how + + align:start position:0% +different rate depending on how + + + align:start position:0% +different rate depending on how +frequently it's needed in natural life + + align:start position:0% +frequently it's needed in natural life + + + align:start position:0% +frequently it's needed in natural life +of these + + align:start position:0% + + + + align:start position:0% + +animals can you answer this question for + + align:start position:0% +animals can you answer this question for + + + align:start position:0% +animals can you answer this question for +me is it true that cats or dogs hunt + + align:start position:0% +me is it true that cats or dogs hunt + + + align:start position:0% +me is it true that cats or dogs hunt +only in order to + + align:start position:0% + + + + align:start position:0% + +eat and describing experiment to test + + align:start position:0% +eat and describing experiment to test + + + align:start position:0% +eat and describing experiment to test +that + + align:start position:0% +that + + + align:start position:0% +that +idea do they hunt only in order to + + align:start position:0% + + + + align:start position:0% + +eat does a cat that's a r and we know he + + align:start position:0% +eat does a cat that's a r and we know he + + + align:start position:0% +eat does a cat that's a r and we know he +hunts for rats and mice does he do that + + align:start position:0% +hunts for rats and mice does he do that + + + align:start position:0% +hunts for rats and mice does he do that +just in order to eat does he do it + + align:start position:0% +just in order to eat does he do it + + + align:start position:0% +just in order to eat does he do it +because he's + + align:start position:0% + + + + align:start position:0% + +hungry well for one thing how can that + + align:start position:0% +hungry well for one thing how can that + + + align:start position:0% +hungry well for one thing how can that +be people that keep pet cats are feeding + + align:start position:0% +be people that keep pet cats are feeding + + + align:start position:0% +be people that keep pet cats are feeding +them they feed them every day these are + + align:start position:0% +them they feed them every day these are + + + align:start position:0% +them they feed them every day these are +not hungry cats well do they just go out + + align:start position:0% +not hungry cats well do they just go out + + + align:start position:0% +not hungry cats well do they just go out +near feeding time + + align:start position:0% +near feeding time + + + align:start position:0% +near feeding time +no well how can you prove that the + + align:start position:0% +no well how can you prove that the + + + align:start position:0% +no well how can you prove that the +motivation to eat and the motivation to + + align:start position:0% +motivation to eat and the motivation to + + + align:start position:0% +motivation to eat and the motivation to +hunt are quite + + align:start position:0% +hunt are quite + + + align:start position:0% +hunt are quite +separate well you can get that a deprive + + align:start position:0% +separate well you can get that a deprive + + + align:start position:0% +separate well you can get that a deprive +the cat of abil of opportunities to + + align:start position:0% +the cat of abil of opportunities to + + + align:start position:0% +the cat of abil of opportunities to +hunt so his eagerness to hunt builds + + align:start position:0% +hunt so his eagerness to hunt builds + + + align:start position:0% +hunt so his eagerness to hunt builds +up okay + + align:start position:0% +up okay + + + align:start position:0% +up okay +and now + + align:start position:0% +and now + + + align:start position:0% +and now +we put him in a situation where he has + + align:start position:0% +we put him in a situation where he has + + + align:start position:0% +we put him in a situation where he has +to say cross + + align:start position:0% +to say cross + + + align:start position:0% +to say cross +over a dish of tuna fish his favorite + + align:start position:0% +over a dish of tuna fish his favorite + + + align:start position:0% +over a dish of tuna fish his favorite +food just in order to get out and + + align:start position:0% +food just in order to get out and + + + align:start position:0% +food just in order to get out and +Hunt what does he do does he run to the + + align:start position:0% +Hunt what does he do does he run to the + + + align:start position:0% +Hunt what does he do does he run to the +tuna + + align:start position:0% +tuna + + + align:start position:0% +tuna +fish no he'll leap right over it to get + + align:start position:0% +fish no he'll leap right over it to get + + + align:start position:0% +fish no he'll leap right over it to get +out there and hunt and that's been seen + + align:start position:0% +out there and hunt and that's been seen + + + align:start position:0% +out there and hunt and that's been seen +in brain stimulation studies where you + + align:start position:0% +in brain stimulation studies where you + + + align:start position:0% +in brain stimulation studies where you +can stimulate the mood that causes them + + align:start position:0% +can stimulate the mood that causes them + + + align:start position:0% +can stimulate the mood that causes them +to be to go into a hunting mood they'll + + align:start position:0% +to be to go into a hunting mood they'll + + + align:start position:0% +to be to go into a hunting mood they'll +leap over dishes everything just to get + + align:start position:0% +leap over dishes everything just to get + + + align:start position:0% +leap over dishes everything just to get +at a mouse or a + + align:start position:0% +at a mouse or a + + + align:start position:0% +at a mouse or a +rat because the motivation to hunt is + + align:start position:0% +rat because the motivation to hunt is + + + align:start position:0% +rat because the motivation to hunt is +quite + + align:start position:0% + + + + align:start position:0% + +separate so it's pretty easy to do an + + align:start position:0% +separate so it's pretty easy to do an + + + align:start position:0% +separate so it's pretty easy to do an +experiment to show that and it has + + align:start position:0% +experiment to show that and it has + + + align:start position:0% +experiment to show that and it has +certainly been + + align:start position:0% + + + + align:start position:0% + +done and similar we can talk about + + align:start position:0% +done and similar we can talk about + + + align:start position:0% +done and similar we can talk about +species that they + + align:start position:0% +species that they + + + align:start position:0% +species that they +don't they don't hunt and kill in the + + align:start position:0% +don't they don't hunt and kill in the + + + align:start position:0% +don't they don't hunt and kill in the +same way that the cats do but they still + + align:start position:0% +same way that the cats do but they still + + + align:start position:0% +same way that the cats do but they still +hunt uh for insects like Lawrence's + + align:start position:0% +hunt uh for insects like Lawrence's + + + align:start position:0% +hunt uh for insects like Lawrence's +starlings uh those + + align:start position:0% +starlings uh those + + + align:start position:0% +starlings uh those +starlings normally when they feed they + + align:start position:0% +starlings normally when they feed they + + + align:start position:0% +starlings normally when they feed they +are poking their bills into the bark of + + align:start position:0% +are poking their bills into the bark of + + + align:start position:0% +are poking their bills into the bark of +trees + + align:start position:0% +trees + + + align:start position:0% +trees +or in leaves and they're poking using + + align:start position:0% +or in leaves and they're poking using + + + align:start position:0% +or in leaves and they're poking using +their bills to poke well if you feed the + + align:start position:0% +their bills to poke well if you feed the + + + align:start position:0% +their bills to poke well if you feed the +it's a pet Starling and you're feeding + + align:start position:0% +it's a pet Starling and you're feeding + + + align:start position:0% +it's a pet Starling and you're feeding +him all the time so he's not hungry that + + align:start position:0% +him all the time so he's not hungry that + + + align:start position:0% +him all the time so he's not hungry that +animal will feed in order to + + align:start position:0% +animal will feed in order to + + + align:start position:0% +animal will feed in order to +poke was the normal sequence who be + + align:start position:0% +poke was the normal sequence who be + + + align:start position:0% +poke was the normal sequence who be +poking in order to get food but now he + + align:start position:0% +poking in order to get food but now he + + + align:start position:0% +poking in order to get food but now he +will he will feed just to be able to + + align:start position:0% +will he will feed just to be able to + + + align:start position:0% +will he will feed just to be able to +poke the cactus uh Finch and the + + align:start position:0% +poke the cactus uh Finch and the + + + align:start position:0% +poke the cactus uh Finch and the +Galapagos is a very interesting + + align:start position:0% +Galapagos is a very interesting + + + align:start position:0% +Galapagos is a very interesting +bird here here you see the a finch and + + align:start position:0% +bird here here you see the a finch and + + + align:start position:0% +bird here here you see the a finch and +it looks like he's got this long + + align:start position:0% +it looks like he's got this long + + + align:start position:0% +it looks like he's got this long +extension of his beak it what it is is a + + align:start position:0% +extension of his beak it what it is is a + + + align:start position:0% +extension of his beak it what it is is a +a cactus thorn + + align:start position:0% +a cactus thorn + + + align:start position:0% +a cactus thorn +that the the bird has found and he uses + + align:start position:0% +that the the bird has found and he uses + + + align:start position:0% +that the the bird has found and he uses +that and all Cactus finches do this they + + align:start position:0% +that and all Cactus finches do this they + + + align:start position:0% +that and all Cactus finches do this they +get that thorn and they use that to poke + + align:start position:0% +get that thorn and they use that to poke + + + align:start position:0% +get that thorn and they use that to poke +deeper into crevices in Cactus and other + + align:start position:0% +deeper into crevices in Cactus and other + + + align:start position:0% +deeper into crevices in Cactus and other +places in order to get food and if you + + align:start position:0% +places in order to get food and if you + + + align:start position:0% +places in order to get food and if you +deprive that Cactus Finch of opportunity + + align:start position:0% +deprive that Cactus Finch of opportunity + + + align:start position:0% +deprive that Cactus Finch of opportunity +to use the thorn that + + align:start position:0% +to use the thorn that + + + align:start position:0% +to use the thorn that +way they will they're highly motivated + + align:start position:0% +way they will they're highly motivated + + + align:start position:0% +way they will they're highly motivated +to do that okay and even if he's wellfed + + align:start position:0% +to do that okay and even if he's wellfed + + + align:start position:0% +to do that okay and even if he's wellfed +he will take the he will search for The + + align:start position:0% +he will take the he will search for The + + + align:start position:0% +he will take the he will search for The +Thorn take the thorn and he'll be out + + align:start position:0% +Thorn take the thorn and he'll be out + + + align:start position:0% +Thorn take the thorn and he'll be out +poking okay because it's a separate + + align:start position:0% + + + + align:start position:0% + +motivation okay now I want to talk + + align:start position:0% +motivation okay now I want to talk + + + align:start position:0% +motivation okay now I want to talk +specifically about the sensory side of + + align:start position:0% +specifically about the sensory side of + + + align:start position:0% +specifically about the sensory side of +these innate behavior + + align:start position:0% + + + + align:start position:0% + +patterns we call the mechanism on that + + align:start position:0% +patterns we call the mechanism on that + + + align:start position:0% +patterns we call the mechanism on that +side the inate releasing mechanism that + + align:start position:0% +side the inate releasing mechanism that + + + align:start position:0% +side the inate releasing mechanism that +was a theoretical term introduced by + + align:start position:0% +was a theoretical term introduced by + + + align:start position:0% +was a theoretical term introduced by +ethologists who did not actually study + + align:start position:0% +ethologists who did not actually study + + + align:start position:0% +ethologists who did not actually study +the nervous + + align:start position:0% +the nervous + + + align:start position:0% +the nervous +system okay but they knew there was an + + align:start position:0% +system okay but they knew there was an + + + align:start position:0% +system okay but they knew there was an +innate releasing + + align:start position:0% + + + + align:start position:0% + +mechanism I've seen this + + align:start position:0% +mechanism I've seen this + + + align:start position:0% +mechanism I've seen this +statement and I want you to criticize it + + align:start position:0% +statement and I want you to criticize it + + + align:start position:0% +statement and I want you to criticize it +the innate releasing mechanism responds + + align:start position:0% +the innate releasing mechanism responds + + + align:start position:0% +the innate releasing mechanism responds +to complex stimulus configurations and + + align:start position:0% +to complex stimulus configurations and + + + align:start position:0% +to complex stimulus configurations and +triggers the behavioral response from + + align:start position:0% +triggers the behavioral response from + + + align:start position:0% +triggers the behavioral response from +the organism M sort of a definition of + + align:start position:0% +the organism M sort of a definition of + + + align:start position:0% +the organism M sort of a definition of +innate behavior in some people's view + + align:start position:0% +innate behavior in some people's view + + + align:start position:0% +innate behavior in some people's view +but what's wrong with + + align:start position:0% + + + + align:start position:0% + +it there's a couple of glaring things + + align:start position:0% +it there's a couple of glaring things + + + align:start position:0% +it there's a couple of glaring things +wrong with it first of + + align:start position:0% +wrong with it first of + + + align:start position:0% +wrong with it first of +all these innate releasing mechanis + + align:start position:0% +all these innate releasing mechanis + + + align:start position:0% +all these innate releasing mechanis +mechanisms are at + + align:start position:0% +mechanisms are at + + + align:start position:0% +mechanisms are at +least at the onset when the animal is + + align:start position:0% +least at the onset when the animal is + + + align:start position:0% +least at the onset when the animal is +Young are not responding to complex + + align:start position:0% +Young are not responding to complex + + + align:start position:0% +Young are not responding to complex +stimulus configuration they're + + align:start position:0% +stimulus configuration they're + + + align:start position:0% +stimulus configuration they're +responding to very simple + + align:start position:0% +responding to very simple + + + align:start position:0% +responding to very simple +stimuli and if the response is say of + + align:start position:0% +stimuli and if the response is say of + + + align:start position:0% +stimuli and if the response is say of +the young to the + + align:start position:0% +the young to the + + + align:start position:0% +the young to the +mother he doesn't respond to her as a as + + align:start position:0% +mother he doesn't respond to her as a as + + + align:start position:0% +mother he doesn't respond to her as a as +an individual he responds to specific + + align:start position:0% +an individual he responds to specific + + + align:start position:0% +an individual he responds to specific +stimuli presented by that mother like + + align:start position:0% +stimuli presented by that mother like + + + align:start position:0% +stimuli presented by that mother like +the Herring GS responding to the orange + + align:start position:0% +the Herring GS responding to the orange + + + align:start position:0% +the Herring GS responding to the orange +spot on the mother's beak and an earn + + align:start position:0% +spot on the mother's beak and an earn + + + align:start position:0% +spot on the mother's beak and an earn +spot on a pencil will elicit the same + + align:start position:0% +spot on a pencil will elicit the same + + + align:start position:0% +spot on a pencil will elicit the same +kind of gaping behavior for feeding + + align:start position:0% +kind of gaping behavior for feeding + + + align:start position:0% +kind of gaping behavior for feeding +so the stimulus is generally very simple + + align:start position:0% +so the stimulus is generally very simple + + + align:start position:0% +so the stimulus is generally very simple +and they can be multiple but they're + + align:start position:0% +and they can be multiple but they're + + + align:start position:0% +and they can be multiple but they're +very simple + + align:start position:0% +very simple + + + align:start position:0% +very simple +stimuli so that's the first thing that's + + align:start position:0% +stimuli so that's the first thing that's + + + align:start position:0% +stimuli so that's the first thing that's +wrong with it and now I what about the I + + align:start position:0% +wrong with it and now I what about the I + + + align:start position:0% +wrong with it and now I what about the I +say elicits the behavior as if we're + + align:start position:0% +say elicits the behavior as if we're + + + align:start position:0% +say elicits the behavior as if we're +talking about a reflex but we're not + + align:start position:0% +talking about a reflex but we're not + + + align:start position:0% +talking about a reflex but we're not +talking about reflexes the response will + + align:start position:0% +talking about reflexes the response will + + + align:start position:0% +talking about reflexes the response will +not + + align:start position:0% +not + + + align:start position:0% +not +occur if the motivation level isn't high + + align:start position:0% +occur if the motivation level isn't high + + + align:start position:0% +occur if the motivation level isn't high +that action specific + + align:start position:0% +that action specific + + + align:start position:0% +that action specific +potential okay so there's no inevitable + + align:start position:0% +potential okay so there's no inevitable + + + align:start position:0% +potential okay so there's no inevitable +elicitation of these fixed action + + align:start position:0% +elicitation of these fixed action + + + align:start position:0% +elicitation of these fixed action +patterns the fixed motor component the + + align:start position:0% +patterns the fixed motor component the + + + align:start position:0% +patterns the fixed motor component the +fixed motor pattern component of a fixed + + align:start position:0% +fixed motor pattern component of a fixed + + + align:start position:0% +fixed motor pattern component of a fixed +action pattern that's what's wrong with + + align:start position:0% +action pattern that's what's wrong with + + + align:start position:0% +action pattern that's what's wrong with +the statement we're not dealing with + + align:start position:0% +the statement we're not dealing with + + + align:start position:0% +the statement we're not dealing with +reflexes so let's just give examples of + + align:start position:0% +reflexes so let's just give examples of + + + align:start position:0% +reflexes so let's just give examples of +the Simplicity of the key steami we + + align:start position:0% +the Simplicity of the key steami we + + + align:start position:0% +the Simplicity of the key steami we +talked about the I just mentioned the + + align:start position:0% +talked about the I just mentioned the + + + align:start position:0% +talked about the I just mentioned the +hering gull chicks uh you remember the + + align:start position:0% +hering gull chicks uh you remember the + + + align:start position:0% +hering gull chicks uh you remember the +stickleback fish very simple stimuli in + + align:start position:0% +stickleback fish very simple stimuli in + + + align:start position:0% +stickleback fish very simple stimuli in +the the female that the male responds to + + align:start position:0% +the the female that the male responds to + + + align:start position:0% +the the female that the male responds to +in order to + + align:start position:0% +in order to + + + align:start position:0% +in order to +initiate + + align:start position:0% +initiate + + + align:start position:0% +initiate +his specific actions and leading the + + align:start position:0% +his specific actions and leading the + + + align:start position:0% +his specific actions and leading the +female to his net in order to get her to + + align:start position:0% +female to his net in order to get her to + + + align:start position:0% +female to his net in order to get her to +lay eggs in + + align:start position:0% +lay eggs in + + + align:start position:0% +lay eggs in +it they're not complex + + align:start position:0% +it they're not complex + + + align:start position:0% +it they're not complex +stimuli it's very simple + + align:start position:0% +stimuli it's very simple + + + align:start position:0% +stimuli it's very simple +shapes that are resembled in some + + align:start position:0% +shapes that are resembled in some + + + align:start position:0% +shapes that are resembled in some +way a fish with a SW swollen belly they + + align:start position:0% +way a fish with a SW swollen belly they + + + align:start position:0% +way a fish with a SW swollen belly they +don't even have to look much much like + + align:start position:0% +don't even have to look much much like + + + align:start position:0% +don't even have to look much much like +fish to + + align:start position:0% + + + + align:start position:0% + +us Lawrence mentions the uh the stinging + + align:start position:0% +us Lawrence mentions the uh the stinging + + + align:start position:0% +us Lawrence mentions the uh the stinging +response of the female common tick this + + align:start position:0% +response of the female common tick this + + + align:start position:0% +response of the female common tick this +was an example he got from + + align:start position:0% +was an example he got from + + + align:start position:0% +was an example he got from +yakob in + + align:start position:0% +yakob in + + + align:start position:0% +yakob in +199 uh very simple stimuli elicit that + + align:start position:0% +199 uh very simple stimuli elicit that + + + align:start position:0% +199 uh very simple stimuli elicit that +stinging response of the tick a body + + align:start position:0% +stinging response of the tick a body + + + align:start position:0% +stinging response of the tick a body +temperature of about + + align:start position:0% +temperature of about + + + align:start position:0% +temperature of about +37° and the smell of butyric acid that's + + align:start position:0% +37° and the smell of butyric acid that's + + + align:start position:0% +37° and the smell of butyric acid that's +all it takes and uh we know that the + + align:start position:0% +all it takes and uh we know that the + + + align:start position:0% +all it takes and uh we know that the +tick can fall from a bush onto an + + align:start position:0% +tick can fall from a bush onto an + + + align:start position:0% +tick can fall from a bush onto an +animal and uh we don't think the tick is + + align:start position:0% +animal and uh we don't think the tick is + + + align:start position:0% +animal and uh we don't think the tick is +detecting surface temperatures at a + + align:start position:0% +detecting surface temperatures at a + + + align:start position:0% +detecting surface temperatures at a +distance it probably responds to the + + align:start position:0% +distance it probably responds to the + + + align:start position:0% +distance it probably responds to the +odor of animals passing but then the + + align:start position:0% +odor of animals passing but then the + + + align:start position:0% +odor of animals passing but then the +animal bumps the bush and so forth and + + align:start position:0% +animal bumps the bush and so forth and + + + align:start position:0% +animal bumps the bush and so forth and +the ticks fall onto + + align:start position:0% +the ticks fall onto + + + align:start position:0% +the ticks fall onto +them the stingy response though is + + align:start position:0% +them the stingy response though is + + + align:start position:0% +them the stingy response though is +triggered by those two stimuli that I + + align:start position:0% +triggered by those two stimuli that I + + + align:start position:0% +triggered by those two stimuli that I +mentioned surface temperature plus the + + align:start position:0% +mentioned surface temperature plus the + + + align:start position:0% +mentioned surface temperature plus the +odor you can see the size of it this is + + align:start position:0% +odor you can see the size of it this is + + + align:start position:0% +odor you can see the size of it this is +the tip of a ballpoint pen this is a + + align:start position:0% +the tip of a ballpoint pen this is a + + + align:start position:0% +the tip of a ballpoint pen this is a +tick from a dog and here are some deer + + align:start position:0% +tick from a dog and here are some deer + + + align:start position:0% +tick from a dog and here are some deer +ticks which are a little + + align:start position:0% +ticks which are a little + + + align:start position:0% +ticks which are a little +smaller known for spreading diseases + + align:start position:0% +smaller known for spreading diseases + + + align:start position:0% +smaller known for spreading diseases +like lime's disease it's spread by deer + + align:start position:0% + + + + align:start position:0% + +ticks so the other he talks about the + + align:start position:0% +ticks so the other he talks about the + + + align:start position:0% +ticks so the other he talks about the +common Cricket females response to in + + align:start position:0% +common Cricket females response to in + + + align:start position:0% +common Cricket females response to in +males she's responding to the specific + + align:start position:0% +males she's responding to the specific + + + align:start position:0% +males she's responding to the specific +pitch of the M's courtship song and + + align:start position:0% +pitch of the M's courtship song and + + + align:start position:0% +pitch of the M's courtship song and +different species of crickets have + + align:start position:0% +different species of crickets have + + + align:start position:0% +different species of crickets have +slightly different pitches of + + align:start position:0% +slightly different pitches of + + + align:start position:0% +slightly different pitches of +sound so females of their own species + + align:start position:0% +sound so females of their own species + + + align:start position:0% +sound so females of their own species +will + + align:start position:0% +will + + + align:start position:0% +will +respond just if the pitch is right and + + align:start position:0% +respond just if the pitch is right and + + + align:start position:0% +respond just if the pitch is right and +that's there's something very similar in + + align:start position:0% +that's there's something very similar in + + + align:start position:0% +that's there's something very similar in +mosquitoes the male responds to specific + + align:start position:0% +mosquitoes the male responds to specific + + + align:start position:0% +mosquitoes the male responds to specific +frequencies of the female's Wing beads + + align:start position:0% +frequencies of the female's Wing beads + + + align:start position:0% +frequencies of the female's Wing beads +that buzzing sound we hear when we hear + + align:start position:0% +that buzzing sound we hear when we hear + + + align:start position:0% +that buzzing sound we hear when we hear +a female flying around that's a very + + align:start position:0% +a female flying around that's a very + + + align:start position:0% +a female flying around that's a very +meaningful stimulus for the the male uh + + align:start position:0% +meaningful stimulus for the the male uh + + + align:start position:0% +meaningful stimulus for the the male uh +looking for a female to meet + + align:start position:0% +looking for a female to meet + + + align:start position:0% +looking for a female to meet +with so the stimuli are are very + + align:start position:0% +with so the stimuli are are very + + + align:start position:0% +with so the stimuli are are very +simple let's talk about the contribution + + align:start position:0% +simple let's talk about the contribution + + + align:start position:0% +simple let's talk about the contribution +of Jerry lethon here at + + align:start position:0% + + + + align:start position:0% + +MIT he died just a couple of years ago + + align:start position:0% +MIT he died just a couple of years ago + + + align:start position:0% +MIT he died just a couple of years ago +um but that was long after his + + align:start position:0% +um but that was long after his + + + align:start position:0% +um but that was long after his +retirement from + + align:start position:0% +retirement from + + + align:start position:0% +retirement from +MIT uh back in + + align:start position:0% +MIT uh back in + + + align:start position:0% +MIT uh back in +the 1959 he published a paper that's one + + align:start position:0% +the 1959 he published a paper that's one + + + align:start position:0% +the 1959 he published a paper that's one +of the most highly cited papers in + + align:start position:0% +of the most highly cited papers in + + + align:start position:0% +of the most highly cited papers in +neuroscience and the title was pretty + + align:start position:0% +neuroscience and the title was pretty + + + align:start position:0% +neuroscience and the title was pretty +far out what the frogs ey tells the + + align:start position:0% +far out what the frogs ey tells the + + + align:start position:0% +far out what the frogs ey tells the +Frog's + + align:start position:0% +Frog's + + + align:start position:0% +Frog's +brain and uh it's a very scholarly paper + + align:start position:0% +brain and uh it's a very scholarly paper + + + align:start position:0% +brain and uh it's a very scholarly paper +that + + align:start position:0% +that + + + align:start position:0% +that +reports uh systematically the + + align:start position:0% +reports uh systematically the + + + align:start position:0% +reports uh systematically the +experiments that he did with machira + + align:start position:0% +experiments that he did with machira + + + align:start position:0% +experiments that he did with machira +South American scientist Warren + + align:start position:0% +South American scientist Warren + + + align:start position:0% +South American scientist Warren +mccullock and uh pittz who was another + + align:start position:0% +mccullock and uh pittz who was another + + + align:start position:0% +mccullock and uh pittz who was another +MIT scientist an + + align:start position:0% +MIT scientist an + + + align:start position:0% +MIT scientist an +engineer + + align:start position:0% +engineer + + + align:start position:0% +engineer +actually + + align:start position:0% +actually + + + align:start position:0% +actually +and this is what they were studying they + + align:start position:0% +and this is what they were studying they + + + align:start position:0% +and this is what they were studying they +were studying + + align:start position:0% +were studying + + + align:start position:0% +were studying +basically they were inspired by the + + align:start position:0% +basically they were inspired by the + + + align:start position:0% +basically they were inspired by the +behavior of the fraud this frog is + + align:start position:0% +behavior of the fraud this frog is + + + align:start position:0% +behavior of the fraud this frog is +responding to the visual stimulus of + + align:start position:0% +responding to the visual stimulus of + + + align:start position:0% +responding to the visual stimulus of +that bug on the leag + + align:start position:0% +that bug on the leag + + + align:start position:0% +that bug on the leag +the bug was flying landed on the leaf + + align:start position:0% +the bug was flying landed on the leaf + + + align:start position:0% +the bug was flying landed on the leaf +the Frog + + align:start position:0% +the Frog + + + align:start position:0% +the Frog +waited he might have made an orienting + + align:start position:0% +waited he might have made an orienting + + + align:start position:0% +waited he might have made an orienting +movement towards + + align:start position:0% +movement towards + + + align:start position:0% +movement towards +that bug and then he simply Waits until + + align:start position:0% +that bug and then he simply Waits until + + + align:start position:0% +that bug and then he simply Waits until +the bug is still and then out comes his + + align:start position:0% +the bug is still and then out comes his + + + align:start position:0% +the bug is still and then out comes his +tongue sticky on the + + align:start position:0% +tongue sticky on the + + + align:start position:0% +tongue sticky on the +end + + align:start position:0% +end + + + align:start position:0% +end +uh and they're normally they're pretty + + align:start position:0% +uh and they're normally they're pretty + + + align:start position:0% +uh and they're normally they're pretty +accurate they only flip their tongue out + + align:start position:0% +accurate they only flip their tongue out + + + align:start position:0% +accurate they only flip their tongue out +when the they're close enough to the uh + + align:start position:0% +when the they're close enough to the uh + + + align:start position:0% +when the they're close enough to the uh +the + + align:start position:0% +the + + + align:start position:0% +the +bug okay so what Leon did he recording + + align:start position:0% +bug okay so what Leon did he recording + + + align:start position:0% +bug okay so what Leon did he recording +electrically you used tiny electrodes in + + align:start position:0% +electrically you used tiny electrodes in + + + align:start position:0% +electrically you used tiny electrodes in +the Frog's + + align:start position:0% +the Frog's + + + align:start position:0% +the Frog's +brain sometimes he did it just from the + + align:start position:0% +brain sometimes he did it just from the + + + align:start position:0% +brain sometimes he did it just from the +stump of the optic nerve because he was + + align:start position:0% +stump of the optic nerve because he was + + + align:start position:0% +stump of the optic nerve because he was +really recording from the accents coming + + align:start position:0% +really recording from the accents coming + + + align:start position:0% +really recording from the accents coming +from the + + align:start position:0% +from the + + + align:start position:0% +from the +retina so it was the activity of retinal + + align:start position:0% +retina so it was the activity of retinal + + + align:start position:0% +retina so it was the activity of retinal +gangling so this was the information + + align:start position:0% +gangling so this was the information + + + align:start position:0% +gangling so this was the information +that reach the midbrain tectum the roof + + align:start position:0% +that reach the midbrain tectum the roof + + + align:start position:0% +that reach the midbrain tectum the roof +of the midbrain where orany + + align:start position:0% +of the midbrain where orany + + + align:start position:0% +of the midbrain where orany +movements are re are + + align:start position:0% +movements are re are + + + align:start position:0% +movements are re are +caused and only after the animal orients + + align:start position:0% +caused and only after the animal orients + + + align:start position:0% +caused and only after the animal orients +and brings it to us the stimulus to a + + align:start position:0% +and brings it to us the stimulus to a + + + align:start position:0% +and brings it to us the stimulus to a +certain part of the + + align:start position:0% +certain part of the + + + align:start position:0% +certain part of the +tectum that then you get the uh tongue + + align:start position:0% +tectum that then you get the uh tongue + + + align:start position:0% +tectum that then you get the uh tongue +flick + + align:start position:0% + + + + align:start position:0% + +response so he was recording from the + + align:start position:0% +response so he was recording from the + + + align:start position:0% +response so he was recording from the +terminal Arbors of aoms coming from the + + align:start position:0% +terminal Arbors of aoms coming from the + + + align:start position:0% +terminal Arbors of aoms coming from the +retina + + align:start position:0% +retina + + + align:start position:0% +retina +there was argument about that for a + + align:start position:0% +there was argument about that for a + + + align:start position:0% +there was argument about that for a +while but he knew when he wrote that + + align:start position:0% +while but he knew when he wrote that + + + align:start position:0% +while but he knew when he wrote that +paper what he must be recording from + + align:start position:0% +paper what he must be recording from + + + align:start position:0% +paper what he must be recording from +because he had recorded even from aons + + align:start position:0% +because he had recorded even from aons + + + align:start position:0% +because he had recorded even from aons +in the + + align:start position:0% +in the + + + align:start position:0% +in the +nerve and he showed four actually there + + align:start position:0% +nerve and he showed four actually there + + + align:start position:0% +nerve and he showed four actually there +were five types of of axons but four + + align:start position:0% +were five types of of axons but four + + + align:start position:0% +were five types of of axons but four +major ones that he described in great + + align:start position:0% +major ones that he described in great + + + align:start position:0% +major ones that he described in great +detail the one that's the most well + + align:start position:0% +detail the one that's the most well + + + align:start position:0% +detail the one that's the most well +known we called Bug + + align:start position:0% +known we called Bug + + + align:start position:0% +known we called Bug +detectors he didn't call it that in the + + align:start position:0% +detectors he didn't call it that in the + + + align:start position:0% +detectors he didn't call it that in the +paper he called them net convexity + + align:start position:0% +paper he called them net convexity + + + align:start position:0% +paper he called them net convexity +detector tors but he did in his + + align:start position:0% +detector tors but he did in his + + + align:start position:0% +detector tors but he did in his +discussion uh his discussion with these + + align:start position:0% +discussion uh his discussion with these + + + align:start position:0% +discussion uh his discussion with these +other scientists he did talk about that + + align:start position:0% +other scientists he did talk about that + + + align:start position:0% +other scientists he did talk about that +what he had given was sort of a a + + align:start position:0% +what he had given was sort of a a + + + align:start position:0% +what he had given was sort of a a +detailed scientific description of a + + align:start position:0% +detailed scientific description of a + + + align:start position:0% +detailed scientific description of a +bug the kind of stimulus that the bug + + align:start position:0% +bug the kind of stimulus that the bug + + + align:start position:0% +bug the kind of stimulus that the bug +presented to the + + align:start position:0% +presented to the + + + align:start position:0% +presented to the +Frog they those acents were part of what + + align:start position:0% +Frog they those acents were part of what + + + align:start position:0% +Frog they those acents were part of what +we call an innate releasing mechanism + + align:start position:0% +we call an innate releasing mechanism + + + align:start position:0% +we call an innate releasing mechanism +for detecting and orienting towards prey + + align:start position:0% +for detecting and orienting towards prey + + + align:start position:0% +for detecting and orienting towards prey +he found another major type that has a + + align:start position:0% +he found another major type that has a + + + align:start position:0% +he found another major type that has a +easily uh discerned function was he + + align:start position:0% +easily uh discerned function was he + + + align:start position:0% +easily uh discerned function was he +called a a dimming detector and it's + + align:start position:0% +called a a dimming detector and it's + + + align:start position:0% +called a a dimming detector and it's +interesting that the dimming detectors + + align:start position:0% +interesting that the dimming detectors + + + align:start position:0% +interesting that the dimming detectors +were uh the activity of much larger axon + + align:start position:0% +were uh the activity of much larger axon + + + align:start position:0% +were uh the activity of much larger axon +very the most rapidly conducting axon in + + align:start position:0% +very the most rapidly conducting axon in + + + align:start position:0% +very the most rapidly conducting axon in +the optic nerve and that's interesting + + align:start position:0% +the optic nerve and that's interesting + + + align:start position:0% +the optic nerve and that's interesting +because these are responding to sudden + + align:start position:0% +because these are responding to sudden + + + align:start position:0% +because these are responding to sudden +dim of the field of the sort that occurs + + align:start position:0% +dim of the field of the sort that occurs + + + align:start position:0% +dim of the field of the sort that occurs +when there's approaching + + align:start position:0% +when there's approaching + + + align:start position:0% +when there's approaching +predator and so the Frog responds in a + + align:start position:0% +predator and so the Frog responds in a + + + align:start position:0% +predator and so the Frog responds in a +completely different way and note that + + align:start position:0% +completely different way and note that + + + align:start position:0% +completely different way and note that +it's very + + align:start position:0% +it's very + + + align:start position:0% +it's very +fast speed is always at a premium when + + align:start position:0% +fast speed is always at a premium when + + + align:start position:0% +fast speed is always at a premium when +it concerns escape from predators so the + + align:start position:0% +it concerns escape from predators so the + + + align:start position:0% +it concerns escape from predators so the +fastest conducting ones were responding + + align:start position:0% +fastest conducting ones were responding + + + align:start position:0% +fastest conducting ones were responding +to the dimming which would be a visual + + align:start position:0% +to the dimming which would be a visual + + + align:start position:0% +to the dimming which would be a visual +stimulus indicating the very likely + + align:start position:0% +stimulus indicating the very likely + + + align:start position:0% +stimulus indicating the very likely +indicating a + + align:start position:0% + + + + align:start position:0% + +Predator okay now because the key + + align:start position:0% +Predator okay now because the key + + + align:start position:0% +Predator okay now because the key +stimuli are so simple you can get very + + align:start position:0% +stimuli are so simple you can get very + + + align:start position:0% +stimuli are so simple you can get very +maladaptive responses in some cases and + + align:start position:0% +maladaptive responses in some cases and + + + align:start position:0% +maladaptive responses in some cases and +these are a couple that he describes + + align:start position:0% +these are a couple that he describes + + + align:start position:0% +these are a couple that he describes +first of all turkey chicks I'll say a + + align:start position:0% +first of all turkey chicks I'll say a + + + align:start position:0% +first of all turkey chicks I'll say a +little more about turkey chicks + + align:start position:0% +little more about turkey chicks + + + align:start position:0% +little more about turkey chicks +responses to Predators but first what + + align:start position:0% +responses to Predators but first what + + + align:start position:0% +responses to Predators but first what +Lawrence says they respond the very same + + align:start position:0% +Lawrence says they respond the very same + + + align:start position:0% +Lawrence says they respond the very same +way to a fat ply crawling across the + + align:start position:0% +way to a fat ply crawling across the + + + align:start position:0% +way to a fat ply crawling across the +ceiling as they do to a hawk flying + + align:start position:0% +ceiling as they do to a hawk flying + + + align:start position:0% +ceiling as they do to a hawk flying +overhead they don't + + align:start position:0% +overhead they don't + + + align:start position:0% +overhead they don't +discriminate so they make maladaptive + + align:start position:0% +discriminate so they make maladaptive + + + align:start position:0% +discriminate so they make maladaptive +Escape + + align:start position:0% + + + + align:start position:0% + +responses and he says that young + + align:start position:0% +responses and he says that young + + + align:start position:0% +responses and he says that young +kestrels have an innate response to + + align:start position:0% +kestrels have an innate response to + + + align:start position:0% +kestrels have an innate response to +water they'll make bathing movements but + + align:start position:0% +water they'll make bathing movements but + + + align:start position:0% +water they'll make bathing movements but +they'll do the same thing just to + + align:start position:0% +they'll do the same thing just to + + + align:start position:0% +they'll do the same thing just to +they'll respond to the stimuli from a + + align:start position:0% +they'll respond to the stimuli from a + + + align:start position:0% +they'll respond to the stimuli from a +marble + + align:start position:0% +marble + + + align:start position:0% +marble +tabletop because of the glassy + + align:start position:0% +tabletop because of the glassy + + + align:start position:0% +tabletop because of the glassy +surface that's the only stimulus needed + + align:start position:0% +surface that's the only stimulus needed + + + align:start position:0% +surface that's the only stimulus needed +to elicit the bathing response was + + align:start position:0% +to elicit the bathing response was + + + align:start position:0% +to elicit the bathing response was +obviously not very adaptive these are + + align:start position:0% +obviously not very adaptive these are + + + align:start position:0% +obviously not very adaptive these are +just showing older Kestrel there's the + + align:start position:0% +just showing older Kestrel there's the + + + align:start position:0% +just showing older Kestrel there's the +turkey baby now a little more about that + + align:start position:0% +turkey baby now a little more about that + + + align:start position:0% +turkey baby now a little more about that +this is an experiment + + align:start position:0% +this is an experiment + + + align:start position:0% +this is an experiment +done not too long ago 2001 in the + + align:start position:0% +done not too long ago 2001 in the + + + align:start position:0% +done not too long ago 2001 in the +journal + + align:start position:0% +journal + + + align:start position:0% +journal +Behavior where some nice experiments + + align:start position:0% +Behavior where some nice experiments + + + align:start position:0% +Behavior where some nice experiments +were done + + align:start position:0% +were done + + + align:start position:0% +were done +on turkey chicks why did they use the + + align:start position:0% +on turkey chicks why did they use the + + + align:start position:0% +on turkey chicks why did they use the +this particular particular turkey chick + + align:start position:0% +this particular particular turkey chick + + + align:start position:0% +this particular particular turkey chick +because it was + + align:start position:0% +because it was + + + align:start position:0% +because it was +born uh it was + + align:start position:0% +born uh it was + + + align:start position:0% +born uh it was +hatched + + align:start position:0% +hatched + + + align:start position:0% +hatched +from slightly below ground and the + + align:start position:0% +from slightly below ground and the + + + align:start position:0% +from slightly below ground and the +ground warms up and the Egg ha hatches + + align:start position:0% +ground warms up and the Egg ha hatches + + + align:start position:0% +ground warms up and the Egg ha hatches +no parents around they just hatch and + + align:start position:0% +no parents around they just hatch and + + + align:start position:0% +no parents around they just hatch and +the eggs are deposited separately so + + align:start position:0% +the eggs are deposited separately so + + + align:start position:0% +the eggs are deposited separately so +there's no siblings around either so + + align:start position:0% +there's no siblings around either so + + + align:start position:0% +there's no siblings around either so +they're not exposed to any social cues + + align:start position:0% +they're not exposed to any social cues + + + align:start position:0% +they're not exposed to any social cues +that could teach them anything about + + align:start position:0% +that could teach them anything about + + + align:start position:0% +that could teach them anything about +Predators so if they're going to be able + + align:start position:0% +Predators so if they're going to be able + + + align:start position:0% +Predators so if they're going to be able +to escape from predators when they're + + align:start position:0% +to escape from predators when they're + + + align:start position:0% +to escape from predators when they're +first hatched you know the response has + + align:start position:0% +first hatched you know the response has + + + align:start position:0% +first hatched you know the response has +to be innate and that's why they pick + + align:start position:0% +to be innate and that's why they pick + + + align:start position:0% +to be innate and that's why they pick +this little + + align:start position:0% + + + + align:start position:0% + +chick uh they live solitarily of course + + align:start position:0% +chick uh they live solitarily of course + + + align:start position:0% +chick uh they live solitarily of course +except when they need to + + align:start position:0% +except when they need to + + + align:start position:0% +except when they need to +make they kept them in a large outdo + + align:start position:0% +make they kept them in a large outdo + + + align:start position:0% +make they kept them in a large outdo +door + + align:start position:0% +door + + + align:start position:0% +door +Avery set in a natural rainforest + + align:start position:0% +Avery set in a natural rainforest + + + align:start position:0% +Avery set in a natural rainforest +habitat similar to where they would + + align:start position:0% +habitat similar to where they would + + + align:start position:0% +habitat similar to where they would +normally be found now in these graphs + + align:start position:0% +normally be found now in these graphs + + + align:start position:0% +normally be found now in these graphs +each black bar + + align:start position:0% +each black bar + + + align:start position:0% +each black bar +shows the + + align:start position:0% +shows the + + + align:start position:0% +shows the +amount of a certain kind of behavior + + align:start position:0% +amount of a certain kind of behavior + + + align:start position:0% +amount of a certain kind of behavior +they saw uh in in this case running + + align:start position:0% +they saw uh in in this case running + + + align:start position:0% +they saw uh in in this case running +Behavior okay so the animal is running + + align:start position:0% +Behavior okay so the animal is running + + + align:start position:0% +Behavior okay so the animal is running +in response to the stimuli listed here + + align:start position:0% +in response to the stimuli listed here + + + align:start position:0% +in response to the stimuli listed here +the first bars there are response to a + + align:start position:0% +the first bars there are response to a + + + align:start position:0% +the first bars there are response to a +live cat walking through the the Avy the + + align:start position:0% +live cat walking through the the Avy the + + + align:start position:0% +live cat walking through the the Avy the +second one to a live dog + + align:start position:0% +second one to a live dog + + + align:start position:0% +second one to a live dog +the third one to a snake model okay they + + align:start position:0% +the third one to a snake model okay they + + + align:start position:0% +the third one to a snake model okay they +didn't use a live snake but they had a + + align:start position:0% +didn't use a live snake but they had a + + + align:start position:0% +didn't use a live snake but they had a +model of a snake Okay and as you know + + align:start position:0% +model of a snake Okay and as you know + + + align:start position:0% +model of a snake Okay and as you know +models of snakes can look exactly like a + + align:start position:0% +models of snakes can look exactly like a + + + align:start position:0% +models of snakes can look exactly like a +snake Okay those are the three stimuli + + align:start position:0% +snake Okay those are the three stimuli + + + align:start position:0% +snake Okay those are the three stimuli +that caus the most + + align:start position:0% +that caus the most + + + align:start position:0% +that caus the most +running the stimuli that corresponded to + + align:start position:0% +running the stimuli that corresponded to + + + align:start position:0% +running the stimuli that corresponded to +a model of a Raptor so it's a hawk + + align:start position:0% +a model of a Raptor so it's a hawk + + + align:start position:0% +a model of a Raptor so it's a hawk +model looked like a hawk shape gliding + + align:start position:0% +model looked like a hawk shape gliding + + + align:start position:0% +model looked like a hawk shape gliding +overhead didn't cause the running what + + align:start position:0% +overhead didn't cause the running what + + + align:start position:0% +overhead didn't cause the running what +it did what it did cause was the second + + align:start position:0% +it did what it did cause was the second + + + align:start position:0% +it did what it did cause was the second +response here crouching more crouching + + align:start position:0% +response here crouching more crouching + + + align:start position:0% +response here crouching more crouching +in response to that overhead stimulus + + align:start position:0% +in response to that overhead stimulus + + + align:start position:0% +in response to that overhead stimulus +than + + align:start position:0% +than + + + align:start position:0% +than +any than than in any of the other + + align:start position:0% +any than than in any of the other + + + align:start position:0% +any than than in any of the other +stimuli a little more to cats than to + + align:start position:0% +stimuli a little more to cats than to + + + align:start position:0% +stimuli a little more to cats than to +dogs but mostly to the Raptors but now + + align:start position:0% +dogs but mostly to the Raptors but now + + + align:start position:0% +dogs but mostly to the Raptors but now +notice another thing oh this this one + + align:start position:0% +notice another thing oh this this one + + + align:start position:0% +notice another thing oh this this one +here uh when they they suddenly appear + + align:start position:0% +here uh when they they suddenly appear + + + align:start position:0% +here uh when they they suddenly appear +very Vigilant with their head up and + + align:start position:0% +very Vigilant with their head up and + + + align:start position:0% +very Vigilant with their head up and +they search most with their eyes that + + align:start position:0% +they search most with their eyes that + + + align:start position:0% +they search most with their eyes that +response was elicited most by + + align:start position:0% +response was elicited most by + + + align:start position:0% +response was elicited most by +recordings not of turkey sounds but + + align:start position:0% + + + + align:start position:0% + +of alarm calls of strong birds that live + + align:start position:0% +of alarm calls of strong birds that live + + + align:start position:0% +of alarm calls of strong birds that live +in that + + align:start position:0% +in that + + + align:start position:0% +in that +Forest indicating that these birds + + align:start position:0% +Forest indicating that these birds + + + align:start position:0% +Forest indicating that these birds +almost as soon as they're hatched + + align:start position:0% +almost as soon as they're hatched + + + align:start position:0% +almost as soon as they're hatched +respond to those alarm + + align:start position:0% +respond to those alarm + + + align:start position:0% +respond to those alarm +calls not to turkey calls but to alarm + + align:start position:0% +calls not to turkey calls but to alarm + + + align:start position:0% +calls not to turkey calls but to alarm +calls of other birds birds that live in + + align:start position:0% +calls of other birds birds that live in + + + align:start position:0% +calls of other birds birds that live in +the same + + align:start position:0% +the same + + + align:start position:0% +the same +place and they're responding mostly by + + align:start position:0% +place and they're responding mostly by + + + align:start position:0% +place and they're responding mostly by +that vigilance Behavior what they're + + align:start position:0% +that vigilance Behavior what they're + + + align:start position:0% +that vigilance Behavior what they're +looking for of course + + align:start position:0% +looking for of course + + + align:start position:0% +looking for of course +is + + align:start position:0% +is + + + align:start position:0% +is +Predators but now there's a black bar + + align:start position:0% +Predators but now there's a black bar + + + align:start position:0% +Predators but now there's a black bar +and a white bar the black bar is to + + align:start position:0% +and a white bar the black bar is to + + + align:start position:0% +and a white bar the black bar is to +their the live cat and mouse or their + + align:start position:0% +their the live cat and mouse or their + + + align:start position:0% +their the live cat and mouse or their +realistic model the white bars are the + + align:start position:0% +realistic model the white bars are the + + + align:start position:0% +realistic model the white bars are the +response to control stimuli the control + + align:start position:0% +response to control stimuli the control + + + align:start position:0% +response to control stimuli the control +stimuli were in the case of the cat dog + + align:start position:0% +stimuli were in the case of the cat dog + + + align:start position:0% +stimuli were in the case of the cat dog +and + + align:start position:0% +and + + + align:start position:0% +and +us and Raptor they're just cardboard + + align:start position:0% +us and Raptor they're just cardboard + + + align:start position:0% +us and Raptor they're just cardboard +boxes they colored the cardboard + + align:start position:0% +boxes they colored the cardboard + + + align:start position:0% +boxes they colored the cardboard +boxes so they were they controlled for + + align:start position:0% +boxes so they were they controlled for + + + align:start position:0% +boxes so they were they controlled for +the color but not detail for shape and + + align:start position:0% +the color but not detail for shape and + + + align:start position:0% +the color but not detail for shape and +you can see they're usually responding + + align:start position:0% +you can see they're usually responding + + + align:start position:0% +you can see they're usually responding +the same way to the boxes in the case of + + align:start position:0% +the same way to the boxes in the case of + + + align:start position:0% +the same way to the boxes in the case of +the snake they used just a simple + + align:start position:0% +the snake they used just a simple + + + align:start position:0% +the snake they used just a simple +cardboard + + align:start position:0% +cardboard + + + align:start position:0% +cardboard +cylinder that was very effective but + + align:start position:0% +cylinder that was very effective but + + + align:start position:0% +cylinder that was very effective but +there were exceptions to that + + align:start position:0% +there were exceptions to that + + + align:start position:0% +there were exceptions to that +in other words the only thing about this + + align:start position:0% +in other words the only thing about this + + + align:start position:0% +in other words the only thing about this +one that made it a raptor was that it + + align:start position:0% +one that made it a raptor was that it + + + align:start position:0% +one that made it a raptor was that it +was up here and it was about the right + + align:start position:0% +was up here and it was about the right + + + align:start position:0% +was up here and it was about the right +bead of movement and the right side + + align:start position:0% +bead of movement and the right side + + + align:start position:0% +bead of movement and the right side +that's all that was required but notice + + align:start position:0% +that's all that was required but notice + + + align:start position:0% +that's all that was required but notice +here this is the recordings of sound + + align:start position:0% +here this is the recordings of sound + + + align:start position:0% +here this is the recordings of sound +here there was a significant difference + + align:start position:0% +here there was a significant difference + + + align:start position:0% +here there was a significant difference +between the experimental sounds the + + align:start position:0% +between the experimental sounds the + + + align:start position:0% +between the experimental sounds the +recording of the actual alarm calls and + + align:start position:0% +recording of the actual alarm calls and + + + align:start position:0% +recording of the actual alarm calls and +just white noise cuz white noise was the + + align:start position:0% +just white noise cuz white noise was the + + + align:start position:0% +just white noise cuz white noise was the +control here okay so there they have a + + align:start position:0% +control here okay so there they have a + + + align:start position:0% +control here okay so there they have a +specific response specific + + align:start position:0% +specific response specific + + + align:start position:0% +specific response specific +differences and perhaps in the case of + + align:start position:0% +differences and perhaps in the case of + + + align:start position:0% +differences and perhaps in the case of +the + + align:start position:0% +the + + + align:start position:0% +the +Raptor um there as I mentioned once + + align:start position:0% +Raptor um there as I mentioned once + + + align:start position:0% +Raptor um there as I mentioned once +before in the class there is some + + align:start position:0% +before in the class there is some + + + align:start position:0% +before in the class there is some +evidence that they + + align:start position:0% +evidence that they + + + align:start position:0% +evidence that they +U they have some specificity of response + + align:start position:0% +U they have some specificity of response + + + align:start position:0% +U they have some specificity of response +but you can see here they couldn't + + align:start position:0% +but you can see here they couldn't + + + align:start position:0% +but you can see here they couldn't +confirm it that they it had anything to + + align:start position:0% +confirm it that they it had anything to + + + align:start position:0% +confirm it that they it had anything to +do with the hawk + + align:start position:0% +do with the hawk + + + align:start position:0% +do with the hawk +shap that doesn't mean that later on + + align:start position:0% +shap that doesn't mean that later on + + + align:start position:0% +shap that doesn't mean that later on +doesn't because they can habituate to + + align:start position:0% +doesn't because they can habituate to + + + align:start position:0% +doesn't because they can habituate to +other shapes and they and not to the uh + + align:start position:0% +other shapes and they and not to the uh + + + align:start position:0% +other shapes and they and not to the uh +the hawk if their experience is teaching + + align:start position:0% +the hawk if their experience is teaching + + + align:start position:0% +the hawk if their experience is teaching +them something else but it's interesting + + align:start position:0% +them something else but it's interesting + + + align:start position:0% +them something else but it's interesting +how non-specific some of these fixed + + align:start position:0% +how non-specific some of these fixed + + + align:start position:0% +how non-specific some of these fixed +action the key stimuli can be they're + + align:start position:0% +action the key stimuli can be they're + + + align:start position:0% +action the key stimuli can be they're +very very + + align:start position:0% +very very + + + align:start position:0% +very very +simple what we see is the hawk what they + + align:start position:0% +simple what we see is the hawk what they + + + align:start position:0% +simple what we see is the hawk what they +see is just something up there that's + + align:start position:0% +see is just something up there that's + + + align:start position:0% +see is just something up there that's +about the size of a hawk and moving in a + + align:start position:0% +about the size of a hawk and moving in a + + + align:start position:0% +about the size of a hawk and moving in a +certain way okay + + align:start position:0% +certain way okay + + + align:start position:0% +certain way okay +do humans show maladaptive responses to + + align:start position:0% +do humans show maladaptive responses to + + + align:start position:0% +do humans show maladaptive responses to +key stimuli + + align:start position:0% +key stimuli + + + align:start position:0% +key stimuli +tuo they certainly do we eat too much + + align:start position:0% +tuo they certainly do we eat too much + + + align:start position:0% +tuo they certainly do we eat too much +sugar we eat high fat foods because it + + align:start position:0% +sugar we eat high fat foods because it + + + align:start position:0% +sugar we eat high fat foods because it +tastes better and the restaurants always + + align:start position:0% +tastes better and the restaurants always + + + align:start position:0% +tastes better and the restaurants always +add extra sugar and + + align:start position:0% +add extra sugar and + + + align:start position:0% +add extra sugar and +fat restaurants are a horror horror for + + align:start position:0% +fat restaurants are a horror horror for + + + align:start position:0% +fat restaurants are a horror horror for +diabetics I've learned that I always + + align:start position:0% +diabetics I've learned that I always + + + align:start position:0% +diabetics I've learned that I always +have trouble with my blood sugar after + + align:start position:0% +have trouble with my blood sugar after + + + align:start position:0% +have trouble with my blood sugar after +eating at a restaurant so I ose my + + align:start position:0% +eating at a restaurant so I ose my + + + align:start position:0% +eating at a restaurant so I ose my +restaurants very very carefully and + + align:start position:0% +restaurants very very carefully and + + + align:start position:0% +restaurants very very carefully and +generally won't go to them at + + align:start position:0% +generally won't go to them at + + + align:start position:0% +generally won't go to them at +all what about other things I picked + + align:start position:0% +all what about other things I picked + + + align:start position:0% +all what about other things I picked +this quote from the internet that I + + align:start position:0% +this quote from the internet that I + + + align:start position:0% +this quote from the internet that I +found this just couple just last year + + align:start position:0% +found this just couple just last year + + + align:start position:0% +found this just couple just last year +like all animals humans have instincts + + align:start position:0% +like all animals humans have instincts + + + align:start position:0% +like all animals humans have instincts +genetically hard hardwired behaviors + + align:start position:0% +genetically hard hardwired behaviors + + + align:start position:0% +genetically hard hardwired behaviors +that enhance our ability to cope with + + align:start position:0% +that enhance our ability to cope with + + + align:start position:0% +that enhance our ability to cope with +vital environmental contingencies our + + align:start position:0% +vital environmental contingencies our + + + align:start position:0% +vital environmental contingencies our +innate fear of snakes is an + + align:start position:0% +innate fear of snakes is an + + + align:start position:0% +innate fear of snakes is an +example other instincts including denial + + align:start position:0% +example other instincts including denial + + + align:start position:0% +example other instincts including denial +Revenge tribal loyalty greed and our + + align:start position:0% +Revenge tribal loyalty greed and our + + + align:start position:0% +Revenge tribal loyalty greed and our +urge to procreate now threaten our very + + align:start position:0% +urge to procreate now threaten our very + + + align:start position:0% +urge to procreate now threaten our very +existence in other words it's important + + align:start position:0% +existence in other words it's important + + + align:start position:0% +existence in other words it's important +we come to + + align:start position:0% +we come to + + + align:start position:0% +we come to +understand our own fixed action + + align:start position:0% + + + + align:start position:0% + +patterns let's talk about one more thing + + align:start position:0% +patterns let's talk about one more thing + + + align:start position:0% +patterns let's talk about one more thing +here Lawrence's discussion of the + + align:start position:0% +here Lawrence's discussion of the + + + align:start position:0% +here Lawrence's discussion of the +transposability of key stimuli all he + + align:start position:0% +transposability of key stimuli all he + + + align:start position:0% +transposability of key stimuli all he +means is that animals are + + align:start position:0% +means is that animals are + + + align:start position:0% +means is that animals are +responding not the exact size of the + + align:start position:0% +responding not the exact size of the + + + align:start position:0% +responding not the exact size of the +stimuli usually doesn't matter but it's + + align:start position:0% +stimuli usually doesn't matter but it's + + + align:start position:0% +stimuli usually doesn't matter but it's +the if it's the configuration at all + + align:start position:0% +the if it's the configuration at all + + + align:start position:0% +the if it's the configuration at all +this is unlike in those turkeys where + + align:start position:0% +this is unlike in those turkeys where + + + align:start position:0% +this is unlike in those turkeys where +the size and movement were seem to be + + align:start position:0% +the size and movement were seem to be + + + align:start position:0% +the size and movement were seem to be +critical but in most cases it's the + + align:start position:0% +critical but in most cases it's the + + + align:start position:0% +critical but in most cases it's the +relationship between stimuli just like + + align:start position:0% +relationship between stimuli just like + + + align:start position:0% +relationship between stimuli just like +the relationship between sounds in a + + align:start position:0% +the relationship between sounds in a + + + align:start position:0% +the relationship between sounds in a +song We recognize the song even though + + align:start position:0% +song We recognize the song even though + + + align:start position:0% +song We recognize the song even though +the pitch may vary a lot and the + + align:start position:0% +the pitch may vary a lot and the + + + align:start position:0% +the pitch may vary a lot and the +loudness may vary a lot we can still + + align:start position:0% +loudness may vary a lot we can still + + + align:start position:0% +loudness may vary a lot we can still +recognize + + align:start position:0% +recognize + + + align:start position:0% +recognize +it + + align:start position:0% +it + + + align:start position:0% +it +uh and you can use dummy stimuli I just + + align:start position:0% +uh and you can use dummy stimuli I just + + + align:start position:0% +uh and you can use dummy stimuli I just +drew some of these uh most little birds + + align:start position:0% +drew some of these uh most little birds + + + align:start position:0% +drew some of these uh most little birds +uh nesting crushes they respond to any + + align:start position:0% +uh nesting crushes they respond to any + + + align:start position:0% +uh nesting crushes they respond to any +stimulus that's even remotely similar to + + align:start position:0% +stimulus that's even remotely similar to + + + align:start position:0% +stimulus that's even remotely similar to +a bird all it has to have is a a top + + align:start position:0% +a bird all it has to have is a a top + + + align:start position:0% +a bird all it has to have is a a top +part that's about one3 the size of the + + align:start position:0% +part that's about one3 the size of the + + + align:start position:0% +part that's about one3 the size of the +bottom part and they will show gaping + + align:start position:0% +bottom part and they will show gaping + + + align:start position:0% +bottom part and they will show gaping +it's about all they all they require + + align:start position:0% +it's about all they all they require + + + align:start position:0% +it's about all they all they require +seems very stupid what they're doing but + + align:start position:0% +seems very stupid what they're doing but + + + align:start position:0% +seems very stupid what they're doing but +that's all that's required and if you + + align:start position:0% +that's all that's required and if you + + + align:start position:0% +that's all that's required and if you +have two sticks like this they're + + align:start position:0% +have two sticks like this they're + + + align:start position:0% +have two sticks like this they're +presented like this they'll always + + align:start position:0% +presented like this they'll always + + + align:start position:0% +presented like this they'll always +respond to the upper one if they're + + align:start position:0% +respond to the upper one if they're + + + align:start position:0% +respond to the upper one if they're +presented once much closer then they + + align:start position:0% +presented once much closer then they + + + align:start position:0% +presented once much closer then they +will respond if it's presented + + align:start position:0% +will respond if it's presented + + + align:start position:0% +will respond if it's presented +horizontally anyway they'll respond to + + align:start position:0% +horizontally anyway they'll respond to + + + align:start position:0% +horizontally anyway they'll respond to +the uh the nearer one but if they're + + align:start position:0% +the uh the nearer one but if they're + + + align:start position:0% +the uh the nearer one but if they're +presented like this even though this is + + align:start position:0% +presented like this even though this is + + + align:start position:0% +presented like this even though this is +near they'll still go for the upper one + + align:start position:0% +near they'll still go for the upper one + + + align:start position:0% +near they'll still go for the upper one +because it it's just a matter of + + align:start position:0% +because it it's just a matter of + + + align:start position:0% +because it it's just a matter of +probabilities what they're likely to + + align:start position:0% +probabilities what they're likely to + + + align:start position:0% +probabilities what they're likely to +encounter in that Nest when they're + + align:start position:0% +encounter in that Nest when they're + + + align:start position:0% +encounter in that Nest when they're +feeding and these simple stimulus + + align:start position:0% +feeding and these simple stimulus + + + align:start position:0% +feeding and these simple stimulus +properties have been exploited by other + + align:start position:0% +properties have been exploited by other + + + align:start position:0% +properties have been exploited by other +birds birds like the Kaku that lay their + + align:start position:0% +birds birds like the Kaku that lay their + + + align:start position:0% +birds birds like the Kaku that lay their +nest in other birds + + align:start position:0% +nest in other birds + + + align:start position:0% +nest in other birds +nest because those other birds + + align:start position:0% +nest because those other birds + + + align:start position:0% +nest because those other birds +respond to the egg in fact if it's a + + align:start position:0% +respond to the egg in fact if it's a + + + align:start position:0% +respond to the egg in fact if it's a +little larger they might respond better + + align:start position:0% +little larger they might respond better + + + align:start position:0% +little larger they might respond better +to + + align:start position:0% +to + + + align:start position:0% +to +it often the eggs depending on the the + + align:start position:0% +it often the eggs depending on the the + + + align:start position:0% +it often the eggs depending on the the +uh parasitic bird uh resembles their egg + + align:start position:0% +uh parasitic bird uh resembles their egg + + + align:start position:0% +uh parasitic bird uh resembles their egg +in the case of the caku it doesn't + + align:start position:0% +in the case of the caku it doesn't + + + align:start position:0% +in the case of the caku it doesn't +always in the case of the white bird the + + align:start position:0% +always in the case of the white bird the + + + align:start position:0% +always in the case of the white bird the +egg mimics their own the Egg of the + + align:start position:0% +egg mimics their own the Egg of the + + + align:start position:0% +egg mimics their own the Egg of the +species they they Cooling and getting to + + align:start position:0% +species they they Cooling and getting to + + + align:start position:0% +species they they Cooling and getting to +raise their young and even their babies + + align:start position:0% +raise their young and even their babies + + + align:start position:0% +raise their young and even their babies +look like the other species for a while + + align:start position:0% +look like the other species for a while + + + align:start position:0% +look like the other species for a while +whdas are much more innocuous in that + + align:start position:0% +whdas are much more innocuous in that + + + align:start position:0% +whdas are much more innocuous in that +they don't destroy the other birds in + + align:start position:0% +they don't destroy the other birds in + + + align:start position:0% +they don't destroy the other birds in +the nest but the cuu is horrible you + + align:start position:0% +the nest but the cuu is horrible you + + + align:start position:0% +the nest but the cuu is horrible you +know it puts its egg in there and it + + align:start position:0% +know it puts its egg in there and it + + + align:start position:0% +know it puts its egg in there and it +hatches at least one of those eggs won't + + align:start position:0% +hatches at least one of those eggs won't + + + align:start position:0% +hatches at least one of those eggs won't +even survive the the the chick won't + + align:start position:0% +even survive the the the chick won't + + + align:start position:0% +even survive the the the chick won't +even survive and in many cases no other + + align:start position:0% +even survive and in many cases no other + + + align:start position:0% +even survive and in many cases no other +little birds will survive just the caku + + align:start position:0% +little birds will survive just the caku + + + align:start position:0% +little birds will survive just the caku +so why do they do + + align:start position:0% + + + + align:start position:0% + +it Lauren says there it's their Vice + + align:start position:0% +it Lauren says there it's their Vice + + + align:start position:0% +it Lauren says there it's their Vice +they they can't you know a vice is + + align:start position:0% +they they can't you know a vice is + + + align:start position:0% +they they can't you know a vice is +you're following an instinct that's bad + + align:start position:0% +you're following an instinct that's bad + + + align:start position:0% +you're following an instinct that's bad +for you he says a vice of these birds is + + align:start position:0% +for you he says a vice of these birds is + + + align:start position:0% +for you he says a vice of these birds is +they they respond to the gaping response + + align:start position:0% +they they respond to the gaping response + + + align:start position:0% +they they respond to the gaping response +of these look at look at the gape here + + align:start position:0% +of these look at look at the gape here + + + align:start position:0% +of these look at look at the gape here +of the kuu here's this enormous chick + + align:start position:0% +of the kuu here's this enormous chick + + + align:start position:0% +of the kuu here's this enormous chick +with this huge gape and there's the Reed + + align:start position:0% +with this huge gape and there's the Reed + + + align:start position:0% +with this huge gape and there's the Reed +warbler feeding + + align:start position:0% +warbler feeding + + + align:start position:0% +warbler feeding +him that's his vice he can't + + align:start position:0% +him that's his vice he can't + + + align:start position:0% +him that's his vice he can't +resist okay so think about why they why + + align:start position:0% +resist okay so think about why they why + + + align:start position:0% +resist okay so think about why they why +don't the birds evolve some way to avoid + + align:start position:0% +don't the birds evolve some way to avoid + + + align:start position:0% +don't the birds evolve some way to avoid +this being taken advantage of and having + + align:start position:0% +this being taken advantage of and having + + + align:start position:0% +this being taken advantage of and having +their own reproduction go + + align:start position:0% +their own reproduction go + + + align:start position:0% +their own reproduction go +down because another bird they're + + align:start position:0% +down because another bird they're + + + align:start position:0% +down because another bird they're +raising other Bird's chicks we'll talk + + align:start position:0% +raising other Bird's chicks we'll talk + + + align:start position:0% +raising other Bird's chicks we'll talk +about that next time \ No newline at end of file diff --git a/fp7wylcPRKM.txt b/fp7wylcPRKM.txt new file mode 100644 index 0000000000000000000000000000000000000000..7f10238ae75c55cd22096b61fce4568b3efebb33 --- /dev/null +++ b/fp7wylcPRKM.txt @@ -0,0 +1,1819 @@ +align:start position:0% + +okay so as Kristen said I'm barbert Huey + + align:start position:0% +okay so as Kristen said I'm barbert Huey + + + align:start position:0% +okay so as Kristen said I'm barbert Huey +I teach in the mechanical engineering + + align:start position:0% +I teach in the mechanical engineering + + + align:start position:0% +I teach in the mechanical engineering +department at MIT and I thought you + + align:start position:0% +department at MIT and I thought you + + + align:start position:0% +department at MIT and I thought you +might wanted to see a little bit about + + align:start position:0% +might wanted to see a little bit about + + + align:start position:0% +might wanted to see a little bit about +me so I was more or less from New Jersey + + align:start position:0% +me so I was more or less from New Jersey + + + align:start position:0% +me so I was more or less from New Jersey +I was born in Philadelphia lived in New + + align:start position:0% +I was born in Philadelphia lived in New + + + align:start position:0% +I was born in Philadelphia lived in New +Jersey and outside of + + align:start position:0% +Jersey and outside of + + + align:start position:0% +Jersey and outside of +Philadelphia there we go moved back and + + align:start position:0% +Philadelphia there we go moved back and + + + align:start position:0% +Philadelphia there we go moved back and +forth about 2 and2 years briefly mov to + + align:start position:0% +forth about 2 and2 years briefly mov to + + + align:start position:0% +forth about 2 and2 years briefly mov to +Southern California when + + align:start position:0% +Southern California when + + + align:start position:0% +Southern California when +and in I was undergraduate where I went + + align:start position:0% +and in I was undergraduate where I went + + + align:start position:0% +and in I was undergraduate where I went +in as a physics major I had always loved + + align:start position:0% +in as a physics major I had always loved + + + align:start position:0% +in as a physics major I had always loved +math and physics I ended up coming out + + align:start position:0% +math and physics I ended up coming out + + + align:start position:0% +math and physics I ended up coming out +with with an engineering Physics degree + + align:start position:0% +with with an engineering Physics degree + + + align:start position:0% +with with an engineering Physics degree +in the mechanical and aerospace + + align:start position:0% +in the mechanical and aerospace + + + align:start position:0% +in the mechanical and aerospace +engineering department which was awesome + + align:start position:0% +engineering department which was awesome + + + align:start position:0% +engineering department which was awesome +for what I'm doing now and also for a + + align:start position:0% +for what I'm doing now and also for a + + + align:start position:0% +for what I'm doing now and also for a +lot of the research I did um before I + + align:start position:0% +lot of the research I did um before I + + + align:start position:0% +lot of the research I did um before I +came back to MIT and then I came up to + + align:start position:0% +came back to MIT and then I came up to + + + align:start position:0% +came back to MIT and then I came up to +Boston to get my PhD in physics at MIT + + align:start position:0% +Boston to get my PhD in physics at MIT + + + align:start position:0% +Boston to get my PhD in physics at MIT +very highly esoteric subject that was + + align:start position:0% +very highly esoteric subject that was + + + align:start position:0% +very highly esoteric subject that was +great fun involving quantum mechanics + + align:start position:0% +great fun involving quantum mechanics + + + align:start position:0% +great fun involving quantum mechanics +but not terribly useful and then I + + align:start position:0% +but not terribly useful and then I + + + align:start position:0% +but not terribly useful and then I +worked for a couple small companies in + + align:start position:0% +worked for a couple small companies in + + + align:start position:0% +worked for a couple small companies in +the area mostly doing um applications of + + align:start position:0% +the area mostly doing um applications of + + + align:start position:0% +the area mostly doing um applications of +particle accelerators to medicine and + + align:start position:0% +particle accelerators to medicine and + + + align:start position:0% +particle accelerators to medicine and +actually a lot of it I know you're + + align:start position:0% +actually a lot of it I know you're + + + align:start position:0% +actually a lot of it I know you're +spending the day on sort of Imaging and + + align:start position:0% +spending the day on sort of Imaging and + + + align:start position:0% +spending the day on sort of Imaging and +image processing I did a lot with + + align:start position:0% +image processing I did a lot with + + + align:start position:0% +image processing I did a lot with +positron emission tomography images + + align:start position:0% +positron emission tomography images + + + align:start position:0% +positron emission tomography images +magnetic MRI images things like that and + + align:start position:0% +magnetic MRI images things like that and + + + align:start position:0% +magnetic MRI images things like that and +then in 2002 I came back to MIT to teach + + align:start position:0% +then in 2002 I came back to MIT to teach + + + align:start position:0% +then in 2002 I came back to MIT to teach +the undergraduate measurement and + + align:start position:0% +the undergraduate measurement and + + + align:start position:0% +the undergraduate measurement and +instrumentation class where I basically + + align:start position:0% +instrumentation class where I basically + + + align:start position:0% +instrumentation class where I basically +teach students how to do experiments and + + align:start position:0% +teach students how to do experiments and + + + align:start position:0% +teach students how to do experiments and +we have a project we call go forth and + + align:start position:0% +we have a project we call go forth and + + + align:start position:0% +we have a project we call go forth and +measure where each student picks their + + align:start position:0% +measure where each student picks their + + + align:start position:0% +measure where each student picks their +own project and does something actually + + align:start position:0% +own project and does something actually + + + align:start position:0% +own project and does something actually +Kristen what was your go forth and + + align:start position:0% +Kristen what was your go forth and + + + align:start position:0% +Kristen what was your go forth and +measure + + align:start position:0% +measure + + + align:start position:0% +measure +what was your go forth and measure + + align:start position:0% +what was your go forth and measure + + + align:start position:0% +what was your go forth and measure +project me you oh does anyone like to + + align:start position:0% +project me you oh does anyone like to + + + align:start position:0% +project me you oh does anyone like to +run here track awesome me too I did um I + + align:start position:0% +run here track awesome me too I did um I + + + align:start position:0% +run here track awesome me too I did um I +took a pressure sensor and put it inside + + align:start position:0% +took a pressure sensor and put it inside + + + align:start position:0% +took a pressure sensor and put it inside +a sneaker and I tried running on + + align:start position:0% +a sneaker and I tried running on + + + align:start position:0% +a sneaker and I tried running on +different surfaces and compared the + + align:start position:0% +different surfaces and compared the + + + align:start position:0% +different surfaces and compared the +impact of running on a treadmill versus + + align:start position:0% +impact of running on a treadmill versus + + + align:start position:0% +impact of running on a treadmill versus +running on + + align:start position:0% +running on + + + align:start position:0% +running on +concrete and we have a lot of really + + align:start position:0% +concrete and we have a lot of really + + + align:start position:0% +concrete and we have a lot of really +cool projects like that where people do + + align:start position:0% +cool projects like that where people do + + + align:start position:0% +cool projects like that where people do +everyday things that they're interested + + align:start position:0% +everyday things that they're interested + + + align:start position:0% +everyday things that they're interested +in including food things like that so + + align:start position:0% +in including food things like that so + + + align:start position:0% +in including food things like that so +anyways back to the women's technology + + align:start position:0% +anyways back to the women's technology + + + align:start position:0% +anyways back to the women's technology +program so I came to MIT in 2002 in 2006 + + align:start position:0% +program so I came to MIT in 2002 in 2006 + + + align:start position:0% +program so I came to MIT in 2002 in 2006 +I was asked to expand the existing + + align:start position:0% +I was asked to expand the existing + + + align:start position:0% +I was asked to expand the existing +women's Technology Program which was + + align:start position:0% +women's Technology Program which was + + + align:start position:0% +women's Technology Program which was +founded in 2002 in electrical + + align:start position:0% +founded in 2002 in electrical + + + align:start position:0% +founded in 2002 in electrical +engineering and computer science so most + + align:start position:0% +engineering and computer science so most + + + align:start position:0% +engineering and computer science so most +of what you're doing today would fit + + align:start position:0% +of what you're doing today would fit + + + align:start position:0% +of what you're doing today would fit +more in that um and then we expanded it + + align:start position:0% +more in that um and then we expanded it + + + align:start position:0% +more in that um and then we expanded it +to mechanical engineering and the goal + + align:start position:0% +to mechanical engineering and the goal + + + align:start position:0% +to mechanical engineering and the goal +is to spark high school girls interest + + align:start position:0% +is to spark high school girls interest + + + align:start position:0% +is to spark high school girls interest +in studying engineering and computer + + align:start position:0% +in studying engineering and computer + + + align:start position:0% +in studying engineering and computer +science which is I think exactly the + + align:start position:0% +science which is I think exactly the + + + align:start position:0% +science which is I think exactly the +goal of this program + + align:start position:0% +goal of this program + + + align:start position:0% +goal of this program +too so our approach is to pick girls to + + align:start position:0% +too so our approach is to pick girls to + + + align:start position:0% +too so our approach is to pick girls to +pick students who are rising High School + + align:start position:0% +pick students who are rising High School + + + align:start position:0% +pick students who are rising High School +seniors who are really good and really + + align:start position:0% +seniors who are really good and really + + + align:start position:0% +seniors who are really good and really +interested in math and science but don't + + align:start position:0% +interested in math and science but don't + + + align:start position:0% +interested in math and science but don't +really have a background in engineering + + align:start position:0% +really have a background in engineering + + + align:start position:0% +really have a background in engineering +have maybe heard of engineering people + + align:start position:0% +have maybe heard of engineering people + + + align:start position:0% +have maybe heard of engineering people +maybe tell them you should think about + + align:start position:0% +maybe tell them you should think about + + + align:start position:0% +maybe tell them you should think about +engineering but they don't really know + + align:start position:0% +engineering but they don't really know + + + align:start position:0% +engineering but they don't really know +what it is they haven't taken a lot of + + align:start position:0% +what it is they haven't taken a lot of + + + align:start position:0% +what it is they haven't taken a lot of +engineering classes they're just curious + + align:start position:0% +engineering classes they're just curious + + + align:start position:0% +engineering classes they're just curious +and not sure what they want to major in + + align:start position:0% +and not sure what they want to major in + + + align:start position:0% +and not sure what they want to major in +so we give them a four-week exposure to + + align:start position:0% +so we give them a four-week exposure to + + + align:start position:0% +so we give them a four-week exposure to +engineering there are two curriculum + + align:start position:0% +engineering there are two curriculum + + + align:start position:0% +engineering there are two curriculum +tracks electrical engineering and + + align:start position:0% +tracks electrical engineering and + + + align:start position:0% +tracks electrical engineering and +computer science and then the one that I + + align:start position:0% +computer science and then the one that I + + + align:start position:0% +computer science and then the one that I +run which is mechanical engineering I + + align:start position:0% +run which is mechanical engineering I + + + align:start position:0% +run which is mechanical engineering I +don't have a lot of time so I can't go + + align:start position:0% +don't have a lot of time so I can't go + + + align:start position:0% +don't have a lot of time so I can't go +into too much detail but I'll be happy + + align:start position:0% +into too much detail but I'll be happy + + + align:start position:0% +into too much detail but I'll be happy +happy to answer questions about what we + + align:start position:0% +happy to answer questions about what we + + + align:start position:0% +happy to answer questions about what we +do in them they're mostly Hands-On + + align:start position:0% +do in them they're mostly Hands-On + + + align:start position:0% +do in them they're mostly Hands-On +classes like what you're doing today we + + align:start position:0% +classes like what you're doing today we + + + align:start position:0% +classes like what you're doing today we +of course especially in mechanical + + align:start position:0% +of course especially in mechanical + + + align:start position:0% +of course especially in mechanical +engineering have to teach them a lot of + + align:start position:0% +engineering have to teach them a lot of + + + align:start position:0% +engineering have to teach them a lot of +physics because you can't do much in + + align:start position:0% +physics because you can't do much in + + + align:start position:0% +physics because you can't do much in +mechanical engineering until you have + + align:start position:0% +mechanical engineering until you have + + + align:start position:0% +mechanical engineering until you have +physics but physics is fun it really is + + align:start position:0% +physics but physics is fun it really is + + + align:start position:0% +physics but physics is fun it really is +um and then we try to correct ideas + + align:start position:0% +um and then we try to correct ideas + + + align:start position:0% +um and then we try to correct ideas +about what Engineers are like and what + + align:start position:0% +about what Engineers are like and what + + + align:start position:0% +about what Engineers are like and what +they do and the students give us + + align:start position:0% +they do and the students give us + + + align:start position:0% +they do and the students give us +wonderful quotes such as that they + + align:start position:0% +wonderful quotes such as that they + + + align:start position:0% +wonderful quotes such as that they +realize engineering has so much more + + align:start position:0% +realize engineering has so much more + + + align:start position:0% +realize engineering has so much more +depth and so many more applications + + align:start position:0% +depth and so many more applications + + + align:start position:0% +depth and so many more applications +coming in they have some of the + + align:start position:0% +coming in they have some of the + + + align:start position:0% +coming in they have some of the +preconceptions that you might have which + + align:start position:0% +preconceptions that you might have which + + + align:start position:0% +preconceptions that you might have which +is the Engineers work alone you know + + align:start position:0% +is the Engineers work alone you know + + + align:start position:0% +is the Engineers work alone you know +it's not very exciting not very people + + align:start position:0% +it's not very exciting not very people + + + align:start position:0% +it's not very exciting not very people +oriented but in fact it is you work a + + align:start position:0% +oriented but in fact it is you work a + + + align:start position:0% +oriented but in fact it is you work a +lot in teams as I think you're doing + + align:start position:0% +lot in teams as I think you're doing + + + align:start position:0% +lot in teams as I think you're doing +today and you get to do a whole range of + + align:start position:0% +today and you get to do a whole range of + + + align:start position:0% +today and you get to do a whole range of +applications and make products that are + + align:start position:0% +applications and make products that are + + + align:start position:0% +applications and make products that are +helpful to + + align:start position:0% +helpful to + + + align:start position:0% +helpful to +people we also want to increase + + align:start position:0% +people we also want to increase + + + align:start position:0% +people we also want to increase +confidence of the students by exposing + + align:start position:0% +confidence of the students by exposing + + + align:start position:0% +confidence of the students by exposing +them to female Engineers of all ages + + align:start position:0% +them to female Engineers of all ages + + + align:start position:0% +them to female Engineers of all ages +give them an opportunity to live away + + align:start position:0% +give them an opportunity to live away + + + align:start position:0% +give them an opportunity to live away +from home so it's four weeks living away + + align:start position:0% +from home so it's four weeks living away + + + align:start position:0% +from home so it's four weeks living away +from home you live in the the students + + align:start position:0% +from home you live in the the students + + + align:start position:0% +from home you live in the the students +live in the MIT dorms they live with MIT + + align:start position:0% +live in the MIT dorms they live with MIT + + + align:start position:0% +live in the MIT dorms they live with MIT +undergrads or recent graduates who help + + align:start position:0% +undergrads or recent graduates who help + + + align:start position:0% +undergrads or recent graduates who help +them with their homework and also do + + align:start position:0% +them with their homework and also do + + + align:start position:0% +them with their homework and also do +social outings and everything and the + + align:start position:0% +social outings and everything and the + + + align:start position:0% +social outings and everything and the +classes are taught by graduate students + + align:start position:0% +classes are taught by graduate students + + + align:start position:0% +classes are taught by graduate students +in uh mechanical engineering or + + align:start position:0% +in uh mechanical engineering or + + + align:start position:0% +in uh mechanical engineering or +eecs and uh oh I already said some of + + align:start position:0% +eecs and uh oh I already said some of + + + align:start position:0% +eecs and uh oh I already said some of +this um so again it's a Hands-On uh + + align:start position:0% +this um so again it's a Hands-On uh + + + align:start position:0% +this um so again it's a Hands-On uh +there's 40 students in the ECS track and + + align:start position:0% +there's 40 students in the ECS track and + + + align:start position:0% +there's 40 students in the ECS track and +20 students in the mechanical + + align:start position:0% +20 students in the mechanical + + + align:start position:0% +20 students in the mechanical +engineering track so there's 60 students + + align:start position:0% +engineering track so there's 60 students + + + align:start position:0% +engineering track so there's 60 students +total uh we have Hands-On lab classes + + align:start position:0% +total uh we have Hands-On lab classes + + + align:start position:0% +total uh we have Hands-On lab classes +with projects in mechanical engineering + + align:start position:0% +with projects in mechanical engineering + + + align:start position:0% +with projects in mechanical engineering +we like to have a sort of Capstone + + align:start position:0% +we like to have a sort of Capstone + + + align:start position:0% +we like to have a sort of Capstone +project at the end of each week which + + align:start position:0% +project at the end of each week which + + + align:start position:0% +project at the end of each week which +ranges from building cranes that cons + + align:start position:0% +ranges from building cranes that cons + + + align:start position:0% +ranges from building cranes that cons +sust stay a certain amount of weight uh + + align:start position:0% +sust stay a certain amount of weight uh + + + align:start position:0% +sust stay a certain amount of weight uh +through doing oral presentations making + + align:start position:0% +through doing oral presentations making + + + align:start position:0% +through doing oral presentations making +a poster presentation and then there are + + align:start position:0% +a poster presentation and then there are + + + align:start position:0% +a poster presentation and then there are +two special final week presentations + + align:start position:0% +two special final week presentations + + + align:start position:0% +two special final week presentations +where the eec students build DC motors + + align:start position:0% +where the eec students build DC motors + + + align:start position:0% +where the eec students build DC motors +and the uh wtm students build rub + + align:start position:0% +and the uh wtm students build rub + + + align:start position:0% +and the uh wtm students build rub +Goldberg machines which are basically + + align:start position:0% +Goldberg machines which are basically + + + align:start position:0% +Goldberg machines which are basically +just Chain Reaction machines but the + + align:start position:0% +just Chain Reaction machines but the + + + align:start position:0% +just Chain Reaction machines but the +thing we do to make it possibly a little + + align:start position:0% +thing we do to make it possibly a little + + + align:start position:0% +thing we do to make it possibly a little +more interesting is they have to figure + + align:start position:0% +more interesting is they have to figure + + + align:start position:0% +more interesting is they have to figure +out what's going on in every step so + + align:start position:0% +out what's going on in every step so + + + align:start position:0% +out what's going on in every step so +it's not just trial and error they have + + align:start position:0% +it's not just trial and error they have + + + align:start position:0% +it's not just trial and error they have +to apply the design principles we've + + align:start position:0% +to apply the design principles we've + + + align:start position:0% +to apply the design principles we've +taught them they have to use the physics + + align:start position:0% +taught them they have to use the physics + + + align:start position:0% +taught them they have to use the physics +and the science we've taught them to + + align:start position:0% +and the science we've taught them to + + + align:start position:0% +and the science we've taught them to +figure out what's going on + + align:start position:0% +figure out what's going on + + + align:start position:0% +figure out what's going on +and then make their machine run and we + + align:start position:0% +and then make their machine run and we + + + align:start position:0% +and then make their machine run and we +also do a lot of faculty and Industry + + align:start position:0% +also do a lot of faculty and Industry + + + align:start position:0% +also do a lot of faculty and Industry +guest speakers and tours um we also have + + align:start position:0% +guest speakers and tours um we also have + + + align:start position:0% +guest speakers and tours um we also have +uh as I said MIT students and Rec recent + + align:start position:0% +uh as I said MIT students and Rec recent + + + align:start position:0% +uh as I said MIT students and Rec recent +graduates are the instructors and also + + align:start position:0% +graduates are the instructors and also + + + align:start position:0% +graduates are the instructors and also +the the tutors that live with the + + align:start position:0% +the the tutors that live with the + + + align:start position:0% +the the tutors that live with the +students and these are some photos from + + align:start position:0% +students and these are some photos from + + + align:start position:0% +students and these are some photos from +the motor building for the ECS so this + + align:start position:0% +the motor building for the ECS so this + + + align:start position:0% +the motor building for the ECS so this +is actually the professor who runs it + + align:start position:0% +is actually the professor who runs it + + + align:start position:0% +is actually the professor who runs it +they figure out the design of their + + align:start position:0% +they figure out the design of their + + + align:start position:0% +they figure out the design of their +motor then they do all the Machining + + align:start position:0% +motor then they do all the Machining + + + align:start position:0% +motor then they do all the Machining +they build them in pairs so that's one + + align:start position:0% +they build them in pairs so that's one + + + align:start position:0% +they build them in pairs so that's one +of the completed Motors and they use + + align:start position:0% +of the completed Motors and they use + + + align:start position:0% +of the completed Motors and they use +actually the mechanical engineering shop + + align:start position:0% +actually the mechanical engineering shop + + + align:start position:0% +actually the mechanical engineering shop +to do all + + align:start position:0% +to do all + + + align:start position:0% +to do all +this and then here's some photographs + + align:start position:0% +this and then here's some photographs + + + align:start position:0% +this and then here's some photographs +from the me track where you see a r + + align:start position:0% +from the me track where you see a r + + + align:start position:0% +from the me track where you see a r +Goldberg machine dominoes are of course + + align:start position:0% +Goldberg machine dominoes are of course + + + align:start position:0% +Goldberg machine dominoes are of course +often used uh various types of trip + + align:start position:0% +often used uh various types of trip + + + align:start position:0% +often used uh various types of trip +wires and things uh uh usually pendulums + + align:start position:0% +wires and things uh uh usually pendulums + + + align:start position:0% +wires and things uh uh usually pendulums +and slinkies used and then there's a + + align:start position:0% +and slinkies used and then there's a + + + align:start position:0% +and slinkies used and then there's a +final step they can decide this one for + + align:start position:0% +final step they can decide this one for + + + align:start position:0% +final step they can decide this one for +their final step they pulled aside a + + align:start position:0% +their final step they pulled aside a + + + align:start position:0% +their final step they pulled aside a +curtain that then showed a photograph of + + align:start position:0% +curtain that then showed a photograph of + + + align:start position:0% +curtain that then showed a photograph of +all the students and + + align:start position:0% +all the students and + + + align:start position:0% +all the students and +staff so since 2002 uh reminder again me + + align:start position:0% +staff so since 2002 uh reminder again me + + + align:start position:0% +staff so since 2002 uh reminder again me +started in 2006 but e start in 2002 up + + align:start position:0% +started in 2006 but e start in 2002 up + + + align:start position:0% +started in 2006 but e start in 2002 up +through last summer we've had 744 + + align:start position:0% +through last summer we've had 744 + + + align:start position:0% +through last summer we've had 744 +females uh finish the program uh they + + align:start position:0% +females uh finish the program uh they + + + align:start position:0% +females uh finish the program uh they +all have a they say wtp has a big impact + + align:start position:0% +all have a they say wtp has a big impact + + + align:start position:0% +all have a they say wtp has a big impact +on them many of them as I'll show on the + + align:start position:0% +on them many of them as I'll show on the + + + align:start position:0% +on them many of them as I'll show on the +next slide many of them go into into + + align:start position:0% +next slide many of them go into into + + + align:start position:0% +next slide many of them go into into +engineering some of them after going + + align:start position:0% +engineering some of them after going + + + align:start position:0% +engineering some of them after going +through wtp decide that they actually + + align:start position:0% +through wtp decide that they actually + + + align:start position:0% +through wtp decide that they actually +don't like engineering it's not for them + + align:start position:0% +don't like engineering it's not for them + + + align:start position:0% +don't like engineering it's not for them +that's a perfectly great outcome for us + + align:start position:0% +that's a perfectly great outcome for us + + + align:start position:0% +that's a perfectly great outcome for us +as well because then they have learned + + align:start position:0% +as well because then they have learned + + + align:start position:0% +as well because then they have learned +and save their parents money of sending + + align:start position:0% +and save their parents money of sending + + + align:start position:0% +and save their parents money of sending +them to an engineering school they've + + align:start position:0% +them to an engineering school they've + + + align:start position:0% +them to an engineering school they've +learned oh I don't really like + + align:start position:0% +learned oh I don't really like + + + align:start position:0% +learned oh I don't really like +engineering I want to do something else + + align:start position:0% +engineering I want to do something else + + + align:start position:0% +engineering I want to do something else +so so either outcome is fine we just + + align:start position:0% +so so either outcome is fine we just + + + align:start position:0% +so so either outcome is fine we just +want to expose them and give them a real + + align:start position:0% +want to expose them and give them a real + + + align:start position:0% +want to expose them and give them a real +more realistic view of what engineering + + align:start position:0% +more realistic view of what engineering + + + align:start position:0% +more realistic view of what engineering +actually is many of them would not have + + align:start position:0% +actually is many of them would not have + + + align:start position:0% +actually is many of them would not have +thought of an engineering major or + + align:start position:0% +thought of an engineering major or + + + align:start position:0% +thought of an engineering major or +applying to + + align:start position:0% +applying to + + + align:start position:0% +applying to +MIT and as you see actually many of them + + align:start position:0% +MIT and as you see actually many of them + + + align:start position:0% +MIT and as you see actually many of them +end up apply uh majoring in either + + align:start position:0% +end up apply uh majoring in either + + + align:start position:0% +end up apply uh majoring in either +engineering or computer science more + + align:start position:0% +engineering or computer science more + + + align:start position:0% +engineering or computer science more +than 60% of the alumni have majored or + + align:start position:0% +than 60% of the alumni have majored or + + + align:start position:0% +than 60% of the alumni have majored or +are majoring in engineering or computer + + align:start position:0% +are majoring in engineering or computer + + + align:start position:0% +are majoring in engineering or computer +science many others in U science math uh + + align:start position:0% +science many others in U science math uh + + + align:start position:0% +science many others in U science math uh +a big bunch in business and then a few + + align:start position:0% +a big bunch in business and then a few + + + align:start position:0% +a big bunch in business and then a few +of others so it's highly successful for + + align:start position:0% +of others so it's highly successful for + + + align:start position:0% +of others so it's highly successful for +its goal which really is to get girls + + align:start position:0% +its goal which really is to get girls + + + align:start position:0% +its goal which really is to get girls +interested in majoring and Engineering + + align:start position:0% +interested in majoring and Engineering + + + align:start position:0% +interested in majoring and Engineering +or at the very least to let them know + + align:start position:0% +or at the very least to let them know + + + align:start position:0% +or at the very least to let them know +what engineering is about and this is uh + + align:start position:0% +what engineering is about and this is uh + + + align:start position:0% +what engineering is about and this is uh +I think the class of 2014 probably and + + align:start position:0% +I think the class of 2014 probably and + + + align:start position:0% +I think the class of 2014 probably and +that's our website and so if you have + + align:start position:0% +that's our website and so if you have + + + align:start position:0% +that's our website and so if you have +any question oh no acknowledgements + + align:start position:0% +any question oh no acknowledgements + + + align:start position:0% +any question oh no acknowledgements +first uh I H I couldn't do this alone + + align:start position:0% +first uh I H I couldn't do this alone + + + align:start position:0% +first uh I H I couldn't do this alone +there's a woman who runs the ECS uh + + align:start position:0% +there's a woman who runs the ECS uh + + + align:start position:0% +there's a woman who runs the ECS uh +program and the whole program the Emy + + align:start position:0% +program and the whole program the Emy + + + align:start position:0% +program and the whole program the Emy +program is funded by an amazing woman + + align:start position:0% +program is funded by an amazing woman + + + align:start position:0% +program is funded by an amazing woman +who's in her actually I think she just + + align:start position:0% +who's in her actually I think she just + + + align:start position:0% +who's in her actually I think she just +turned 80 who is a mechanical engineer + + align:start position:0% +turned 80 who is a mechanical engineer + + + align:start position:0% +turned 80 who is a mechanical engineer +and she funds our program and then + + align:start position:0% +and she funds our program and then + + + align:start position:0% +and she funds our program and then +various other people so any + + align:start position:0% + + + + align:start position:0% + +questions + + align:start position:0% +questions + + + align:start position:0% +questions +nothing + + align:start position:0% +nothing + + + align:start position:0% +nothing +okay okay and uh if you are not I know + + align:start position:0% +okay okay and uh if you are not I know + + + align:start position:0% +okay okay and uh if you are not I know +there are some Juniors here which + + align:start position:0% +there are some Juniors here which + + + align:start position:0% +there are some Juniors here which +unfortunately you've missed the deadline + + align:start position:0% +unfortunately you've missed the deadline + + + align:start position:0% +unfortunately you've missed the deadline +for this summer but if you are not a + + align:start position:0% +for this summer but if you are not a + + + align:start position:0% +for this summer but if you are not a +junior if you're a e8th n9th or 10th + + align:start position:0% +junior if you're a e8th n9th or 10th + + + align:start position:0% +junior if you're a e8th n9th or 10th +grader look in around November of your + + align:start position:0% +grader look in around November of your + + + align:start position:0% +grader look in around November of your +junior year on that + + align:start position:0% +junior year on that + + + align:start position:0% +junior year on that +website right there and look for our + + align:start position:0% +website right there and look for our + + + align:start position:0% +website right there and look for our +application information and the + + align:start position:0% +application information and the + + + align:start position:0% +application information and the +applications are usually do at the + + align:start position:0% +applications are usually do at the + + + align:start position:0% +applications are usually do at the +beginning of January okay okay + + align:start position:0% +beginning of January okay okay + + + align:start position:0% +beginning of January okay okay +[Applause] \ No newline at end of file diff --git a/g2mOvmC1TKc.txt b/g2mOvmC1TKc.txt new file mode 100644 index 0000000000000000000000000000000000000000..bd105842b47c14c176604d1a7175c8feea95a761 --- /dev/null +++ b/g2mOvmC1TKc.txt @@ -0,0 +1,395 @@ +align:start position:0% + +now we can use the unique path + + align:start position:0% +now we can use the unique path + + + align:start position:0% +now we can use the unique path +characterization of trees to very + + align:start position:0% +characterization of trees to very + + + align:start position:0% +characterization of trees to very +quickly figure out that every tree is is + + align:start position:0% +quickly figure out that every tree is is + + + align:start position:0% +quickly figure out that every tree is is +two colorable so we know that a tree is + + align:start position:0% +two colorable so we know that a tree is + + + align:start position:0% +two colorable so we know that a tree is +a graph with unique paths between every + + align:start position:0% +a graph with unique paths between every + + + align:start position:0% +a graph with unique paths between every +pair of vertices and as a consequence + + align:start position:0% +pair of vertices and as a consequence + + + align:start position:0% +pair of vertices and as a consequence +the chromatic number of a tree with two + + align:start position:0% +the chromatic number of a tree with two + + + align:start position:0% +the chromatic number of a tree with two +or more vertices is + + align:start position:0% +or more vertices is + + + align:start position:0% +or more vertices is +two um the proof is just to show you uh + + align:start position:0% +two um the proof is just to show you uh + + + align:start position:0% +two um the proof is just to show you uh +how to color it you K clearly can't get + + align:start position:0% +how to color it you K clearly can't get + + + align:start position:0% +how to color it you K clearly can't get +by with one color if you've got any two + + align:start position:0% +by with one color if you've got any two + + + align:start position:0% +by with one color if you've got any two +adjacent vertices uh the two-c colable + + align:start position:0% +adjacent vertices uh the two-c colable + + + align:start position:0% +adjacent vertices uh the two-c colable +way is that you just choose an arbitrary + + align:start position:0% +way is that you just choose an arbitrary + + + align:start position:0% +way is that you just choose an arbitrary +vertex um and call it the root but you + + align:start position:0% +vertex um and call it the root but you + + + align:start position:0% +vertex um and call it the root but you +make the arbitrary choice on what the + + align:start position:0% +make the arbitrary choice on what the + + + align:start position:0% +make the arbitrary choice on what the +root is and uh there's a unique path + + align:start position:0% +root is and uh there's a unique path + + + align:start position:0% +root is and uh there's a unique path +from every vertex from the root to every + + align:start position:0% +from every vertex from the root to every + + + align:start position:0% +from every vertex from the root to every +vertex using this unique path + + align:start position:0% +vertex using this unique path + + + align:start position:0% +vertex using this unique path +characterization and so we're just going + + align:start position:0% +characterization and so we're just going + + + align:start position:0% +characterization and so we're just going +to color vertices by whether the path + + align:start position:0% +to color vertices by whether the path + + + align:start position:0% +to color vertices by whether the path +from the root is of odd or even length + + align:start position:0% +from the root is of odd or even length + + + align:start position:0% +from the root is of odd or even length +if it's of even length color it red and + + align:start position:0% +if it's of even length color it red and + + + align:start position:0% +if it's of even length color it red and +if it's odd length color it blue colored + + align:start position:0% +if it's odd length color it blue colored + + + align:start position:0% +if it's odd length color it blue colored +green and so we wind up alter + + align:start position:0% +green and so we wind up alter + + + align:start position:0% +green and so we wind up alter +red and green and the fact is that uh + + align:start position:0% +red and green and the fact is that uh + + + align:start position:0% +red and green and the fact is that uh +adjacent nodes are going to be at a + + align:start position:0% +adjacent nodes are going to be at a + + + align:start position:0% +adjacent nodes are going to be at a +distance where one is an odd distance + + align:start position:0% +distance where one is an odd distance + + + align:start position:0% +distance where one is an odd distance +and one is an even distance which is why + + align:start position:0% +and one is an even distance which is why + + + align:start position:0% +and one is an even distance which is why +this method of coloring is going to work + + align:start position:0% +this method of coloring is going to work + + + align:start position:0% +this method of coloring is going to work +a general property of two coloring is + + align:start position:0% +a general property of two coloring is + + + align:start position:0% +a general property of two coloring is +that it to figure out whether or not a + + align:start position:0% +that it to figure out whether or not a + + + align:start position:0% +that it to figure out whether or not a +graph is two colorable and how to do it + + align:start position:0% +graph is two colorable and how to do it + + + align:start position:0% +graph is two colorable and how to do it +is you just start uh pick an arbitrary + + align:start position:0% +is you just start uh pick an arbitrary + + + align:start position:0% +is you just start uh pick an arbitrary +vertex give it a color it red and then + + align:start position:0% +vertex give it a color it red and then + + + align:start position:0% +vertex give it a color it red and then +color all the vertices adjacent to it + + align:start position:0% +color all the vertices adjacent to it + + + align:start position:0% +color all the vertices adjacent to it +green and keep going in that way uh + + align:start position:0% +green and keep going in that way uh + + + align:start position:0% +green and keep going in that way uh +coloring a Vertex with a color different + + align:start position:0% +coloring a Vertex with a color different + + + align:start position:0% +coloring a Vertex with a color different +from an adjac bent vertex that's colored + + align:start position:0% +from an adjac bent vertex that's colored + + + align:start position:0% +from an adjac bent vertex that's colored +until you get stuck if you don't get + + align:start position:0% +until you get stuck if you don't get + + + align:start position:0% +until you get stuck if you don't get +stuck it's too colorable and if it's not + + align:start position:0% +stuck it's too colorable and if it's not + + + align:start position:0% +stuck it's too colorable and if it's not +too colorable you're guaranteed to get + + align:start position:0% +too colorable you're guaranteed to get + + + align:start position:0% +too colorable you're guaranteed to get +stuck so it's a very easy way to figure + + align:start position:0% +stuck so it's a very easy way to figure + + + align:start position:0% +stuck so it's a very easy way to figure +out if a graph is two colorable uh + + align:start position:0% +out if a graph is two colorable uh + + + align:start position:0% +out if a graph is two colorable uh +another characterization that of two + + align:start position:0% +another characterization that of two + + + align:start position:0% +another characterization that of two +colorability in general is that um a + + align:start position:0% +colorability in general is that um a + + + align:start position:0% +colorability in general is that um a +graph is too colorable providing that + + align:start position:0% +graph is too colorable providing that + + + align:start position:0% +graph is too colorable providing that +all the cycles that it has if any are of + + align:start position:0% +all the cycles that it has if any are of + + + align:start position:0% +all the cycles that it has if any are of +even length of course a tree has no + + align:start position:0% +even length of course a tree has no + + + align:start position:0% +even length of course a tree has no +Cycles so that makes it too colorable + + align:start position:0% +Cycles so that makes it too colorable + + + align:start position:0% +Cycles so that makes it too colorable +for sure \ No newline at end of file diff --git a/ggxY20cXql8.txt b/ggxY20cXql8.txt new file mode 100644 index 0000000000000000000000000000000000000000..4d5a216192053f9514edaa4786db931fd4f00f51 --- /dev/null +++ b/ggxY20cXql8.txt @@ -0,0 +1,1843 @@ +The following content is +provided under a Creative + +Commons license. + +Your support will help MIT +OpenCourseWare continue to + +offer high quality educational +resources for free. + +To make a donation or view +additional materials from + +hundreds of MIT courses, visit +MIT OpenCourseWare at + +ocw.mit.edu. + +PROFESSOR: I apologize to +those of you watching on + +OpenCourseWare. + +I forgot to turn on +my microphone. + +And you missed some incredibly +brilliant things. + +But such is life. + +Let me go back to where I was, +which was we we're looking at + +this code to find the cube +root of a perfect cube. + +We saw this last week, and +indeed, you also saw it in + +recitation. + +I'm not going to belabor it. + +I do want to ask you the +question, for what values will + +this program terminate? + +That is to say the only +input is to x. + +For what values of +x is this program + +guaranteed to always stop? + +Anybody want to volunteer +an answer to that? + +Ask a simpler question. + +Let's assume that +x is a number. + +In fact, let's assume +it's an integer. + +Will it terminate for all +positive integers, all + +positive values of x? + +Yeah. + +All negative values? + +As far as I can tell. + +How about 0? + +Yeah. + +So in fact, it terminates +for all values of x. + +How do I know that? + +And that's a key question. + +I know that because I've used, +and I mean by used as a mental + +tool, something in my head, +the notion of a + +decrementing function. + +And every time I write a loop, +I think about one of these, + +because that explains to +me why the loop is + +guaranteed to terminate. + +We'll go over here where we have +a bigger board and look + +at the properties that +a decrementing + +function needs to have. + +One, it will map some +set of program + +variables to an integer. + +Two, when the loop is entered +for the first time or when I + +encountered the test of the loop +for the first time, its + +value is non-negative. + +Three, when its value gets to +be less than or equal to 0, + +the loop terminates. + +And finally four, it's +decreased each + +time through the loop. + +So what we see is if it starts +to be a positive value or + +non-negative, and it's decreased +every time I execute + +the body of a loop, that +eventually, it's got to reach + +0 or something less than 0. + +And when it does, +the loop stops. + +If such a function exists, then +the loop is guaranteed to + +always terminate. + +Now, of course, one can count up +to a value instead of down. + +But there's always a trick we +can use of subtracting to make + +it the same. + +So what's the decrementing +function for this loop? + +How did I know it will +always terminate? + +Yeah? + +AUDIENCE: [INAUDIBLE]. + +PROFESSOR: Answer equals +answer plus 1. + +I don't think so. + +Does that satisfy all +of these properties? + +Remember, a function is going +to map some set of program + +variables to an integer. + +So what are the interesting +program variables here? + +Well, there are only +two, ans and x. + +Right? + +At least, that's +all I can see. + +So what would be an interesting +function? + +Somebody? + +Surely, there's someone who +can figure this out. + +Yes? + +Or no, you're just scratching +your head. + +You fooled me. + +I can't see because of the +light, but I'm sure there must + +be dozens of hands up if +I could only see them. + +Actually, I don't see +any hands up. + +This is not so hard, guys. + +It's the absolute value of +x minus answer cubed. + +So what does this +value start at? + +Let's pick a value. + +Suppose that x is equal to 8. + +What is the initial value of +the decrementing function? + +Wow. + +Come on. + +Let's be a little cooperative, +please. + +Yes? + +AUDIENCE: So it's 8, answer +is 0 and absolute + +value of x is 8. + +PROFESSOR: So it's 8 minus +0, which is equal to 8. + +So it satisfies conditions +one and conditions two. + +What happens to this value every +time through the loop? + +Does x change? + +Does answer change? + +And how does it change? + +It's increasing. + +What does answer start at? + +It starts at 0, and +it increases. + +So I know that answer cubed +will always be positive. + +Right? + +So I know that every +time through the + +loop, it will be 8. + +The first time through, +it'll be 8 minus 1 + +cubed, which is 7. + +And then the next time through, +it'll be 8 minus 2 + +cubed, which is 0. + +And then, I exit the loop. + +And it's that kind of reasoning +that I used to + +convince myself that this +loop terminates. + +And every time I write a loop, +and I hope every time you + +write a loop, you will think +about what's the reason the + +loop is going to terminate. + +And you will do it by thinking +about what the decrementing + +function is. + +People get me on that? + +And whoever finally answered +a question surely + +deserves to be fed. + +I obviously have to bring better +candy to encourage + +better responses. + +Now, let's go back and look +at the program itself. + +Now that we know it stops, and +you can take my word for it + +that it actually computes the +correct answer, let's think + +about what kind of algorithm +this is. + +What's the method? + +This is an example of +guess and check. + +And it's a particular kind +called exhaustive enumeration. + +Each time through the loop, I'm +taking a guess at to what + +the value is, and I'm checking +whether it's true. + +But I'm enumerating +the guesses in a + +very systematic way. + +They're not just +random guesses. + +I'm enumerating all the +possible answers. + +If I get through the entire +space of answers, or possible + +answers, and I don't find a +solution, then I know that it + +doesn't exist, and it's +not a perfect cube. + +So that's why it's called +exhaustive enumeration because + +I'm exhausting the space +of possible answers. + +Does that makes sense +to everyone? + +So let's try it. + +Let's try it with say a very +large value of x, because + +that's always an issue, of +course, when we do exhaustive + +enumeration. + +So I'm going to enter +this value. + +Is that a perfect cube? + +Who thinks it is? + +Who can tell me what it is? + +What's the cube root of that? + +Well, this is a question I did +not expect you to answer. + +But it's 1,251. + +That'll be in the first quiz, +so make a note of it. + +Notice how quickly the +computer did this. + +It found the cube +root of quite a + +large number very quickly. + +And so while one might +initially think that + +exhaustive enumeration is a +silly technique because takes + +a lot of guesses, for an awful +lot of problems, we can + +actually just write a pretty +stupid program that's solves + +it by exhaustive enumeration. + +We typically refer to such +programs as brute force. + +And brute force is often +exactly the right + +way to solve a problem. + +Why does it work? + +Because computers +are really fast. + +How fast are computers? + +Well, today, a good computer +can execute in a single + +processor in the order of 100 +million instructions a second. + +How fast is that? + +And now, we're going to see if +Mitchell has answered the + +question I asked in the +way in the class. + +How many instructions can a +computer execute between the + +time I say something and the +time the people in the back + +row hear it? + +Mitch thinks it's 400 million +instructions. + +I think that's about right. + +It's hundreds of millions +at any rate. + +It's kind of amazing between the +time I say something and + +the time you hear it, hundreds +of millions of instructions. + +It's mind boggling +how fast that is. + +And that's why we can often use +these kind of solutions. + +Next lecture, actually, even +a little bit later in this + +lecture, I hope to get to an +example of why that doesn't + +really get the job done, +at least not always. + +Before I do that, I want +to look at one + +more programming construct. + +And that's a variant +on the while loop. + +So if we think about what the +while loop we were just + +looking at did or does, as the +decrementing function told us, + +it's looking at all the possible +values of answer + +ranging from 0 to the +absolute value of x. + +And at each step testing and +doing something, we can + +abstract this process using +something called a for loop. + +So let's look at this code. + +It's essentially exactly +the same algorithm. + +I got bored of typing ans +times ans times ans. + +So I used a Python notation +for exponentiation, which + +you'll see is star, star. + +Now, be easier to read +if I get rid of that. + +But other than that, the +interesting thing I did was + +replace the while +loop by a for. + +So you'll see this line of code +there, for ans in range 0 + +to abs of x plus 1. + +What that says is range is a +built-in function of Python + +that generates, in this case, +a sequence of integers, + +something called a tuple, which +we'll be looking at in a + +lecture or so. + +But for now, it's pretty simple +to think about what you + +get is if you look at the +expression range of x to y, + +that gives me a sequence +of values, x, x plus 1 + +up to y minus 1. + +Notice not up to y, but +up to y minus 1. + +So it gives me a sequence +of length y-- + +well, assuming that's 0. + +Right? + +It doesn't have to be 0. + +It can be anything. + +It can be another +value as well. + +0 in my example. + +And then, the for loop executes +it on this value and + +the next iteration on this +value, and finally, at the + +very end on that value. + +So it executes it one iteration +of the loop on each + +value in this sequence +of values generated + +by the range statement. + +And normally, it does +all of them. + +However, you'll see I've added +something called a break here, + +a command in Python. + +And what break says +is exit the loop. + +So it exits it prematurely +without executing all of the + +values generated by range. + +You can nest loops just like +you nest if statements. + +And if you do that break, +always executes-- + +always exits rather the +innermost loop. + +So what this does is it's +generates a set + +of values to test. + +It checks whether or not +it's got the answer. + +If it does, it terminates +the loop. + +And eventually, you +exit the loop. + +And then, it just checks as +before whether or not it found + +a correct answer and does +the right thing. + +So you'll find, particularly +when you're iterating over + +integers, but later we'll see +when you're iterating over a + +lot of other kinds of things, +for loops are a very + +convenient shorthand. + +There's nothing you can't +do with a while loop. + +You don't need for loops. + +But they do make life easy. + +And over the semester, I think +you'll end up writing a lot + +more for loops than you +will while loops. + +Any questions about this? + +If not, I'm going to +move right along. + +So this is the moment. + +I'm going to move right along. + +So we've now got a program that +does something really + +silly, really. + +It finds cube roots +of perfect cubes. + +Well, that's not typically +useful. + +Right? + +You've even got these $0.50 four +function calculators that + +find square roots. + +And they don't insist that you +only give it perfect squares. + +So now, let's think about how +we would take this kind of + +program, and indeed, this kind +of method of writing programs + +and use it to find-- + +for now, we'll look at the +square root of any number, of + +any floating point number. + +Well, the first question we need +to ask is what do I mean? + +That's kind of a subtle +question. + +What does it mean to find the +square root of a number? + +What does it mean, for +example, to find the + +square root of 2? + +Well, we know that that was an +endless series of digits + +before we can find the +square root of 2. + +Right? + +It does not have +a nice answer. + +So we can't just say we have to +find something that if we + +multiply it by itself, +it will equal 2. + +Because we can't find +such a thing. + +So we've got to think +about a different + +notion of what we mean. + +Furthermore, even for some +numbers which there is a + +square root, it might be a +million decimal places long, + +and consequently, really +hard to find. + +So we need to think +about a different + +kind of concept here. + +And it's the concept of an +approximation, finding an + +answer that is good enough. + +So what should we do here? + +How do we think about this? + +Typically, what we do when we +think about an approximation + +is we define how good +an approximation + +we're willing to accept. + +So for example, we might want +to say, I want to find a + +square root that lies +within epsilon of + +the true square root. + +So find a y such that y times +y is equal to what? + +What does it mean? + +How would I express it within +epsilon of the perfect answer? + +I don't want to say it's equal +to x, because that may be + +impossible or too time +consuming to find. + +So really, what I mean is +x plus or minus epsilon. + +So that's what I'm asking. + +Find one that's close enough. + +And that's what the next +piece of code I + +want to show you does. + +Excuse me. + +So I'm starting, just giving it +a value for x, so I don't + +have to keep typing one in. + +Let's say it's 25. + +I'm going to take epsilon +to be 0.01. + +So I want it within that +distance of the true answer. + +I'm going to keep track of the +number of guesses here, not + +because we need it to actually +compute the answer, but + +because I want to then discuss +how many iterations of the + +loop we're doing. + +We're going to start by setting +my first guess at 0.0. + +Again, this is going to be +exhaustive enumeration. + +Then, I'm going to essentially +encode this as a test of my + +while loop while the absolute +value of answer squared minus + +x is greater than or equal to +epsilon, and answer is less + +than equal to x. + +So it's now a more +complicated test. + +I've got a Boolean value. + +Two things have to be true to +execute the body of the loop. + +I'm going to increment answer +by a tiny amount, increment + +the number of guesses just so +I can keep track of it. + +Maybe I'm going to comment +this out for the first go + +around just so we don't see too +many print statements and + +keep doing it. + +And then when I'm done I'm going +to see whether or not + +what I found is indeed a square +root or close enough. + +So if we think about why this +loop terminates, why am I + +guaranteed that this loop +will terminate? + +What's my decrementing +function here? + +Somebody? + +What's the decrementing +function? + +What am I guaranteed to reduce +each time through, and when I + +get through, I'm done? + +Yeah? + +AUDIENCE: [INAUDIBLE] + +answer squared minus +x1 times 1. + +PROFESSOR: No. + +Close, sort of. + +But I appreciate +you're trying. + +That's worth something +just for the effort. + +Somebody else. + +Remember, if we look at the +properties it has to have, + +it's going to guarantee me that +when it gets to the right + +value, I exit the loop, which +suggests it's going to + +certainly be part of the +test of the while. + +Just look at this piece +over here at the end. + +Answer starts at 0. + +I keep incrementing it. + +Eventually, answer minus x +will hit a value, right? + +Eventually, I'll get to +the point that this + +condition must be true-- + +must be false rather. + +And then, I exit the loop. + +So this piece is not +really the key. + +It's this piece that guarantees +me I'm going to get + +out eventually. + +This piece can get +me out sooner. + +It's kind of an optimization, +if you will. + +So I'm just going to go until +I find the answer. + +Let's see what happens +when I run it. + +It tells me that 4.99, et cetera +is close to the square + +root of 25. + +So there are some things +to note about this. + +First, it didn't find 5, 25 +happens to be a perfect + +square, yet I didn't find it. + +Is that OK? + +Yeah. + +Because that wasn't +what I said. + +What I said is find +a y that has these + +properties over here. + +And I did. + +I didn't say find the y that +gets closest to the + +square root of x. + +I said find one that has +these properties. + +Effectively, what this is is a +specification of the problem. + +And I've now written a piece +of code that meets the + +specification. + +It does what I set out to do, +and that's good enough. + +Now, let's turn this print +statement back on. + +It took almost 1/2 million +guesses to get there. + +But it was still blindingly +fast. + +So once again, exhaustive +enumeration seems to be OK. + +Suppose, however, I choose +a bigger number. + +Now, first, let's choose +something that doesn't have a + +good answer. + +Let's see what it +does for that. + +All right. + +Pretty good. + +Also pretty fast. + +Not too many guesses. + +But now, let's try this one. + +Well, it's going to wait. + +It's going to get done, but it's +going to take a little + +bit longer than maybe +we want it to take. + +Why is it taking so long? + +There it is. + +It found an answer, which +I think is good. + +But as you can see, it +took quite a few + +guesses to get there. + +So why? + +Well, let me first ask +this question. + +Can we look at the code and +anticipate how many guesses + +it's going to have to take? + +We're going back to this issue +of computational complexity, + +but here, not of the problem +but of the solution. + +So this is algorithmic +analysis. + +We're analyzing the algorithm, +this exhaustive enumeration + +algorithm, and trying to figure +out how long it's + +likely to take to run. + +Well, what does the running +time of this + +algorithm depend upon? + +Yeah? + +AUDIENCE: [INAUDIBLE]. + +PROFESSOR: It depends on +the actual square root. + +Yes. + +But in particular, the distance +of the actual square + +root from the starting point. + +So that's one factor +it depends on. + +But that's not the +only factor. + +What else does it depend on? + +Oh, do we have an injury? + +We had a dropped pass and +a deflection there. + +All right. + +Yes? + +AUDIENCE: It depends on the +level of accuracy, so how you + +define epsilon. + +PROFESSOR: It depends upon +the value of epsilon. + +Absolutely. + +How long it takes to run. + +AUDIENCE: [INAUDIBLE]. + +PROFESSOR: Someone with +a concern for safety. + +it depends upon the actual value +of epsilon, because if + +epsilon is small, we may have +to take more steps to get a + +precise enough answer. + +And it depends upon +one more thing. + +Yeah? + +AUDIENCE: [INAUDIBLE] the +increment that [INAUDIBLE]? + +PROFESSOR: The increment. + +Exactly. + +Because the number of times we +go through the loop is going + +to be related to how +big a step we + +take each time through. + +No applause? + +Thank you. + +So it depends upon all +of these things. + +And here, since we're trying +to find a pretty [? big ?] + +square root and a sort of +precise answer, but we're + +taking tiny steps, it's +going to take a + +long time to execute. + +So we could make it faster. + +For example, suppose I change +the step size to this. + +Plus equal by says increment +the value by whatever the + +right side is. + +So I'm going to increment +it by 1. + +Wow, it was really fast. + +But it didn't work. + +It failed. + +That's not so good. + +So I can't just do that. + +And of course, it's not +surprising, because I ended up + +jumping all over the answer. + +I could make epsilon smaller, +but that seems like cheating. + +So really, what I need to do is +find a better algorithm, a + +better way to attack +the problem. + +Fortunately, I don't +have to invent it. + +Some people a lot smarter than +I am figured out a long time + +ago a good method for solving +this kind of problem. + +And they're doing it +using something + +called bisection search. + +As we look at this particular +implementation of it, we're + +going to use two algorithmic +techniques that you'll use + +over and over again because +they're generally useful. + +So the first one related to +bisection search is we'll cut + +the search space in half +each iteration. + +So with my brute force +algorithm, we're trimming the + +search base only a little +bit each step. + +So if we think about it, what it +looks like, we had a space + +of values to search +for the answer. + +And I started here. + +And each step, I just trimmed +off a tiny, tiny little bit, + +0.001, leaving me a lot +of space to search. + +And that's why it +took so long. + +When I do bisection search, the +basic idea is each step I + +want to cut the search +space in half. + +Get rid of half of the search +space each time. + +So one way I could do +it is I start with a + +guess say in the middle. + +Just pick some guess that's in +the middle of my search space. + +And now I say is it too +high or too low? + +I can easily answer +that question. + +I square it. + +See is my result bigger than +the actual square root or + +smaller than the actual +square root? + +That tells me whether my guess +is too big or too small. + +Once I know that, I know which +side of the guess the right + +answer is on. + +So if I knew that my guess was +too big, then I know there's + +no point in looking over +here for my next guess. + +So I can get rid of this +whole half in one step. + +Now, what should my +next guess be? + +Yeah? + +AUDIENCE: [INAUDIBLE]. + +PROFESSOR: My next +guess should be + +half way through there. + +Exactly. + +And now, let's say this time +my answer is too small. + +Then I know I can +get rid of this. + +So now, I'm very quickly pruning +my search space. + +If I think about that, how many +times am I likely to have + +to prune it? + +It's much faster, right? + +As we'll see later, it's +basically log base 2. + +If I have some number of +values to look at-- + +and by the way, how many values +do I have in my search + +space to start with? + +What determines it? + +Clearly, the first value and the +last value, but also, how + +small I'm dividing it up. + +Right? + +So I have to think +about that too. + +What is the precision with +which I do this. + +Am I looking at every +one millionth of a + +number or every 0.01? + +That will tell me +how big it is. + +Once I know how big my search +space is, I know that if I + +search it linearly looking at +every value, my worst cases, I + +look at everything until +I get to the end. + +Well, my best case is +I get lucky, and my + +first guess is right. + +But if I use bisection search, +my worst case is going to be + +log number of values +in that space. + +Because each time, I throw +half of them away. + +We'll see that in more +detail later on. + +Let's go back and look +at the code now. + +So it starts as before with +a value for epsilon. + +But now, I'm going to take a +lower bound, here, and an + +upper bound on my +search space. + +I'm going to say my initial +guess will be the upper bound + +plus the lower bound +over 2 halfway + +through my search space. + +And then, I'm just going to work +my way through it until I + +get to the answer or +don't find it. + +So should we look at what's +going on here? + +Let's try this. + +Well, let's first make sure it +works for a small value. + +Never test your program first +on something big. + +Always try your program in +something small first. + +Let's try it on that. + +Got an answer. + +Notice that it's different from +the answer we got last + +time we looked for the +square root of 25. + +But that's OK, because it's +still meets the specification. + +It's still within epsilon of +the actual square root. + +And I didn't have to say that +I wanted it below or the + +square root or above, just +said within epsilon. + +Sure enough, different +algorithm, different answer, + +but equally good, but +a lot faster. + +Now let's try it for +the big value. + +Wow, that was a lot +faster, wasn't it? + +It got me an answer. + +Probably, not exactly +the same answer as + +before but pretty close. + +But it did it in only +26 guesses. + +Pretty cool. + +And in fact, we'll see over and +over again that bisection + +search is a really good +technique for + +finding quick answers. + +And again, why is it 26? + +Well, we had some number of +guesses to start with. + +After 1, it was half as big, +then a quarter is big, and + +eventually, log 2 of the size. + +But what was the size? + +Was it the number 12345? + +No. + +We already sort of talked +about that. + +What was it? + +Let's look at the code, and +let's think about what was the + +size of our initial +search space. + +It's a little bit tricky to +think about this, right? + +Now, we have to think a little +bit harder about when we exit + +the loop, because in +fundamentally, that's telling + +me the size of the +search space. + +So what determined the size +of the search space? + +Well, we talked about the upper +and the lower bound. + +But what's telling me +roughly speaking how + +many divisions I have? + +It's epsilon. + +It's not 0.01 because when +I square it, it has to be + +smaller than 0.01. + +But that tells me roughly +how many I have. + +And so it's going to be roughly +12345 divided by 0.01 + +squared, which turns out to +be 26.897 more or less. + +So we could predict it. + +And son of a gun, when we ran +it, we actually matched the + +prediction. + +That's the great thing about +algorithmic analysis. + +We can actually get accurate +guesses as to how long a + +program is likely +to take to run. + +This is an important thing +because sometimes we do that + +and we say, oh, it's going +to take a year. + +I better not even try. + +I better find a smarter +algorithm. + +Or we do it and say, well, it's +going to take almost no + +time at all. + +I'm not going to waste +my time looking + +for a smarter algorithm. + +I'm going to live with +the one I've got. + +It's important, and again, as +I said, it's a topic we're + +going to get back to. + +Of course, whether it's +26, 27, or even 50 + +doesn't really matter. + +What matters is it's +not a billion. + +Right? + +Because we don't really care +small differences. + +Whether it takes 25 or it +takes 50 will be an + +imperceptible difference. + +It's whether it's a huge +difference that matters. + +And that's really the kind of +things we're going after is + +orders of magnitude. + +Now, I have a question +about this program. + +I've been obsessing about +whether it's fast enough. + +And we've shown it is. + +But does it work? + +Kind of more important. + +It's always possible to write +a really fast program that + +gives you the wrong answer. + +The problem is to write a fast +program that give you the + +right answer. + +Does this program always work? + +Well, it worked for 25. + +It worked for 12345. + +Is that good enough? + +Probably not. + +We might want to try it +in some other values. + +I'll ask a simpler question. + +Does it always work on +positive values? + +All right. + +I'll give you a hint. + +No. + +It does not. + +I'm not going to, however, +tell you why it doesn't, + +because I want you to +think about it. + +And I want you to +tell me why it + +doesn't in the next lecture. + +But because I'm not a complete +sadist, I'll give you a hint. + +When we use bisection search, or +for that matter, any search + +method, we are depending upon +the fact that the answer lies + +somewhere in the region +we're searching. + +If indeed the answer is out +here or out here, then it + +doesn't matter how carefully +I search this region. + +I'm not going to find +the answer. + +And so this program doesn't work +on some potential values + +of x because the actual square +root of x will not lie in the + +region that the program +is searching. + +I leave it to you to think about +what such values are. + +And we can talk about that +on the next lecture. + +Suppose I want to use this +program to find the cube root. + +Suppose it worked, and +I want it to use it + +to find a cube root. + +What would I have to change? + +How would I change it, so it +found cube roots instead of + +square roots? + +Well, I can take it up. + +I could use cut and paste, and +paste it into my editor and + +get a new program. + +And how would I change +that new program to + +make it do cube roots? + +Not very hard. + +Think only two places +have to get changed. + +That's for the simplicity, +say cube + +roots of positive numbers. + +I think you said the +right thing. + +All I have to do is change that +two to a three and that + +two to a three, and I'm done. + +And I should probably change the +message to say cube root. + +Pretty easy. + +On the other hand, suppose I +also want it to find the + +fourth root, and the fifth +root, and the sixth root, + +however many roots. + +Well, I'm going to get pretty +tired of cutting, and pasting, + +and building a whole +bunch of things. + +So really, what I want to do +is find a way to write the + +code that will find the nth root +of a number for any n. + +To do that, I'm going +to introduce a + +new programming concept. + +And that concept is +the function. + +And that will be the main topic +of Thursday's lecture. \ No newline at end of file diff --git a/hmJMaVYiqwM.txt b/hmJMaVYiqwM.txt new file mode 100644 index 0000000000000000000000000000000000000000..e355a788d822057338a0f6a5762b369df74df64e --- /dev/null +++ b/hmJMaVYiqwM.txt @@ -0,0 +1,3131 @@ +align:start position:0% + +I swore to myself that if I became a + + align:start position:0% +I swore to myself that if I became a + + + align:start position:0% +I swore to myself that if I became a +lecturer I would never more my students + + align:start position:0% +lecturer I would never more my students + + + align:start position:0% +lecturer I would never more my students +that that was a worse sin than almost + + align:start position:0% +that that was a worse sin than almost + + + align:start position:0% +that that was a worse sin than almost +any other a teacher could commit was to + + align:start position:0% +any other a teacher could commit was to + + + align:start position:0% +any other a teacher could commit was to +be boring today on the podcast the film + + align:start position:0% +be boring today on the podcast the film + + + align:start position:0% +be boring today on the podcast the film +experience in this episode we'll explore + + align:start position:0% +experience in this episode we'll explore + + + align:start position:0% +experience in this episode we'll explore +what it takes to reframe historical + + align:start position:0% +what it takes to reframe historical + + + align:start position:0% +what it takes to reframe historical +artifacts things like classic plays + + align:start position:0% +artifacts things like classic plays + + + align:start position:0% +artifacts things like classic plays +books and films for a modern audience + + align:start position:0% +books and films for a modern audience + + + align:start position:0% +books and films for a modern audience +and I said to him what did you actually + + align:start position:0% +and I said to him what did you actually + + + align:start position:0% +and I said to him what did you actually +think Shakespeare's environment was he + + align:start position:0% +think Shakespeare's environment was he + + + align:start position:0% +think Shakespeare's environment was he +somehow had managed to disconnect the + + align:start position:0% +somehow had managed to disconnect the + + + align:start position:0% +somehow had managed to disconnect the +literary power of Shakespeare from the + + align:start position:0% +literary power of Shakespeare from the + + + align:start position:0% +literary power of Shakespeare from the +fact that it was done on this incredibly + + align:start position:0% +fact that it was done on this incredibly + + + align:start position:0% +fact that it was done on this incredibly +popular stage and it was so sensational + + align:start position:0% +popular stage and it was so sensational + + + align:start position:0% +popular stage and it was so sensational +and it was so much more like television + + align:start position:0% +and it was so much more like television + + + align:start position:0% +and it was so much more like television +or the movies than it was like some + + align:start position:0% +or the movies than it was like some + + + align:start position:0% +or the movies than it was like some +process of sitting in a in a library in + + align:start position:0% +process of sitting in a in a library in + + + align:start position:0% +process of sitting in a in a library in +wood-paneled splendor reading words in + + align:start position:0% +wood-paneled splendor reading words in + + + align:start position:0% +wood-paneled splendor reading words in +silence that's not what Shakespeare was + + align:start position:0% +silence that's not what Shakespeare was + + + align:start position:0% +silence that's not what Shakespeare was +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +how can we compare media so that + + align:start position:0% +how can we compare media so that + + + align:start position:0% +how can we compare media so that +students today might better understand + + align:start position:0% +students today might better understand + + + align:start position:0% +students today might better understand +what it originally was + + align:start position:0% +what it originally was + + + align:start position:0% +what it originally was +welcome to chalk radio a podcast about + + align:start position:0% +welcome to chalk radio a podcast about + + + align:start position:0% +welcome to chalk radio a podcast about +inspired teaching at MIT + + align:start position:0% +inspired teaching at MIT + + + align:start position:0% +inspired teaching at MIT +I'm your host Sarah Hansen from MIT + + align:start position:0% +I'm your host Sarah Hansen from MIT + + + align:start position:0% +I'm your host Sarah Hansen from MIT +OpenCourseWare my guest today is a + + align:start position:0% +OpenCourseWare my guest today is a + + + align:start position:0% +OpenCourseWare my guest today is a +longtime professor at MIT I'm David + + align:start position:0% +longtime professor at MIT I'm David + + + align:start position:0% +longtime professor at MIT I'm David +Thorburn I'm a professor of literature + + align:start position:0% +Thorburn I'm a professor of literature + + + align:start position:0% +Thorburn I'm a professor of literature +and comparative media I've taught the + + align:start position:0% +and comparative media I've taught the + + + align:start position:0% +and comparative media I've taught the +film experience for 39 years at MIT + + align:start position:0% +film experience for 39 years at MIT + + + align:start position:0% +film experience for 39 years at MIT +we'll be talking about professor Thor + + align:start position:0% +we'll be talking about professor Thor + + + align:start position:0% +we'll be talking about professor Thor +Byrnes class 21 l01 won the film + + align:start position:0% +Byrnes class 21 l01 won the film + + + align:start position:0% +Byrnes class 21 l01 won the film +experience and like all of the classes + + align:start position:0% +experience and like all of the classes + + + align:start position:0% +experience and like all of the classes +we talked about on this podcast you can + + align:start position:0% +we talked about on this podcast you can + + + align:start position:0% +we talked about on this podcast you can +check out the film experience on OCW + + align:start position:0% +check out the film experience on OCW + + + align:start position:0% +check out the film experience on OCW +website at ocw.mit.edu professor + + align:start position:0% +website at ocw.mit.edu professor + + + align:start position:0% +website at ocw.mit.edu professor +Thorburn made a splash in the academic + + align:start position:0% +Thorburn made a splash in the academic + + + align:start position:0% +Thorburn made a splash in the academic +world by bringing in media that + + align:start position:0% +world by bringing in media that + + + align:start position:0% +world by bringing in media that +traditionally hadn't existed there we'll + + align:start position:0% +traditionally hadn't existed there we'll + + + align:start position:0% +traditionally hadn't existed there we'll +start with how this all came about + + align:start position:0% +start with how this all came about + + + align:start position:0% +start with how this all came about +and what it was like for him to + + align:start position:0% +and what it was like for him to + + + align:start position:0% +and what it was like for him to +challenge what might be considered + + align:start position:0% +challenge what might be considered + + + align:start position:0% +challenge what might be considered +unholy in the sacred space of the + + align:start position:0% +unholy in the sacred space of the + + + align:start position:0% +unholy in the sacred space of the +classroom the story of what made me into + + align:start position:0% +classroom the story of what made me into + + + align:start position:0% +classroom the story of what made me into +a film scholar or a media scholar is at + + align:start position:0% +a film scholar or a media scholar is at + + + align:start position:0% +a film scholar or a media scholar is at +least interesting to me and so it still + + align:start position:0% +least interesting to me and so it still + + + align:start position:0% +least interesting to me and so it still +surprises me I had been teaching at Yale + + align:start position:0% +surprises me I had been teaching at Yale + + + align:start position:0% +surprises me I had been teaching at Yale +for + + align:start position:0% +for + + + align:start position:0% +for +for seven or eight years and I was + + align:start position:0% +for seven or eight years and I was + + + align:start position:0% +for seven or eight years and I was +offered a chance to do a visitation at + + align:start position:0% +offered a chance to do a visitation at + + + align:start position:0% +offered a chance to do a visitation at +the University of California in Santa + + align:start position:0% +the University of California in Santa + + + align:start position:0% +the University of California in Santa +Barbara and I was trying to introduce + + align:start position:0% +Barbara and I was trying to introduce + + + align:start position:0% +Barbara and I was trying to introduce +the students to the idea of conventions + + align:start position:0% +the students to the idea of conventions + + + align:start position:0% +the students to the idea of conventions +what it means when you begin a story + + align:start position:0% +what it means when you begin a story + + + align:start position:0% +what it means when you begin a story +once upon a time and every story begins + + align:start position:0% +once upon a time and every story begins + + + align:start position:0% +once upon a time and every story begins +that way or what it means when you say + + align:start position:0% +that way or what it means when you say + + + align:start position:0% +that way or what it means when you say +they lived happily ever after to take + + align:start position:0% +they lived happily ever after to take + + + align:start position:0% +they lived happily ever after to take +the simplest example of what a + + align:start position:0% +the simplest example of what a + + + align:start position:0% +the simplest example of what a +convention is I was trying to illustrate + + align:start position:0% +convention is I was trying to illustrate + + + align:start position:0% +convention is I was trying to illustrate +how in fact we internalize these things + + align:start position:0% +how in fact we internalize these things + + + align:start position:0% +how in fact we internalize these things +and we understand the conventions of the + + align:start position:0% +and we understand the conventions of the + + + align:start position:0% +and we understand the conventions of the +narratives of our own time in our blood + + align:start position:0% +narratives of our own time in our blood + + + align:start position:0% +narratives of our own time in our blood +without even thinking about it + + align:start position:0% +without even thinking about it + + + align:start position:0% +without even thinking about it +so what I needed to illustrate the + + align:start position:0% +so what I needed to illustrate the + + + align:start position:0% +so what I needed to illustrate the +principle were shared texts so I began + + align:start position:0% +principle were shared texts so I began + + + align:start position:0% +principle were shared texts so I began +by asking them this was in the 1970s in + + align:start position:0% +by asking them this was in the 1970s in + + + align:start position:0% +by asking them this was in the 1970s in +the early 1970s and I asked the students + + align:start position:0% +the early 1970s and I asked the students + + + align:start position:0% +the early 1970s and I asked the students +there these are bright california public + + align:start position:0% +there these are bright california public + + + align:start position:0% +there these are bright california public +school students how many of you have + + align:start position:0% +school students how many of you have + + + align:start position:0% +school students how many of you have +ever seen a John Wayne movie maybe 15% + + align:start position:0% +ever seen a John Wayne movie maybe 15% + + + align:start position:0% +ever seen a John Wayne movie maybe 15% +of the students raised their hand then I + + align:start position:0% +of the students raised their hand then I + + + align:start position:0% +of the students raised their hand then I +said well how many of you have read + + align:start position:0% +said well how many of you have read + + + align:start position:0% +said well how many of you have read +Huckleberry Finn maybe 30% I tried other + + align:start position:0% +Huckleberry Finn maybe 30% I tried other + + + align:start position:0% +Huckleberry Finn maybe 30% I tried other +novels classic novels I tried + + align:start position:0% +novels classic novels I tried + + + align:start position:0% +novels classic novels I tried +Shakespeare plays I was at a lot member + + align:start position:0% +Shakespeare plays I was at a lot member + + + align:start position:0% +Shakespeare plays I was at a lot member +this is in the early seventies finally I + + align:start position:0% +this is in the early seventies finally I + + + align:start position:0% +this is in the early seventies finally I +said how many of you have seen all in + + align:start position:0% +said how many of you have seen all in + + + align:start position:0% +said how many of you have seen all in +the family for those in the audience too + + align:start position:0% +the family for those in the audience too + + + align:start position:0% +the family for those in the audience too +young to know this all in the family was + + align:start position:0% +young to know this all in the family was + + + align:start position:0% +young to know this all in the family was +a television program a classic and + + align:start position:0% +a television program a classic and + + + align:start position:0% +a television program a classic and +transforming one that appeared in 1971 + + align:start position:0% +transforming one that appeared in 1971 + + + align:start position:0% +transforming one that appeared in 1971 +on American television and involved a + + align:start position:0% +on American television and involved a + + + align:start position:0% +on American television and involved a +working-class hero who had never such + + align:start position:0% +working-class hero who had never such + + + align:start position:0% +working-class hero who had never such +characters had never appeared on + + align:start position:0% +characters had never appeared on + + + align:start position:0% +characters had never appeared on +television before was a very important + + align:start position:0% +television before was a very important + + + align:start position:0% +television before was a very important +program and of course a hundred percent + + align:start position:0% +program and of course a hundred percent + + + align:start position:0% +program and of course a hundred percent +of the class had seen it and I began to + + align:start position:0% +of the class had seen it and I began to + + + align:start position:0% +of the class had seen it and I began to +take my examples from television + + align:start position:0% +take my examples from television + + + align:start position:0% +take my examples from television +programs and I became either this + + align:start position:0% +programs and I became either this + + + align:start position:0% +programs and I became either this +maybe I worried on me as the term went + + align:start position:0% +maybe I worried on me as the term went + + + align:start position:0% +maybe I worried on me as the term went +on and I what I realized was that the + + align:start position:0% +on and I what I realized was that the + + + align:start position:0% +on and I what I realized was that the +literature of our own day the story + + align:start position:0% +literature of our own day the story + + + align:start position:0% +literature of our own day the story +forms that belong to my students and to + + align:start position:0% +forms that belong to my students and to + + + align:start position:0% +forms that belong to my students and to +the generation of kids I was teaching + + align:start position:0% +the generation of kids I was teaching + + + align:start position:0% +the generation of kids I was teaching +were visual not literary + + align:start position:0% + + + + align:start position:0% + +so I became interested in television as + + align:start position:0% +so I became interested in television as + + + align:start position:0% +so I became interested in television as +a narrative medium and then I came to + + align:start position:0% +a narrative medium and then I came to + + + align:start position:0% +a narrative medium and then I came to +realize as I began to think more + + align:start position:0% +realize as I began to think more + + + align:start position:0% +realize as I began to think more +seriously about the role of television + + align:start position:0% +seriously about the role of television + + + align:start position:0% +seriously about the role of television +in American like remember by 1970 + + align:start position:0% +in American like remember by 1970 + + + align:start position:0% +in American like remember by 1970 +American television was the dominant + + align:start position:0% +American television was the dominant + + + align:start position:0% +American television was the dominant +form of entertainment and narrative in + + align:start position:0% +form of entertainment and narrative in + + + align:start position:0% +form of entertainment and narrative in +American life and in fact this initial + + align:start position:0% +American life and in fact this initial + + + align:start position:0% +American life and in fact this initial +understanding out of which my whole + + align:start position:0% +understanding out of which my whole + + + align:start position:0% +understanding out of which my whole +interest in media developed has shaped I + + align:start position:0% +interest in media developed has shaped I + + + align:start position:0% +interest in media developed has shaped I +realized now just in talking about this + + align:start position:0% +realized now just in talking about this + + + align:start position:0% +realized now just in talking about this +my way of teaching the film experience + + align:start position:0% + + + + align:start position:0% + +when I got back to Yale after my years + + align:start position:0% +when I got back to Yale after my years + + + align:start position:0% +when I got back to Yale after my years +visitation I introduced a course called + + align:start position:0% +visitation I introduced a course called + + + align:start position:0% +visitation I introduced a course called +literature and popular culture in which + + align:start position:0% +literature and popular culture in which + + + align:start position:0% +literature and popular culture in which +I explored these ideas in greater depth + + align:start position:0% +I explored these ideas in greater depth + + + align:start position:0% +I explored these ideas in greater depth +I read some bestsellers I ended the + + align:start position:0% +I read some bestsellers I ended the + + + align:start position:0% +I read some bestsellers I ended the +course by looking at the honeymooners + + align:start position:0% +course by looking at the honeymooners + + + align:start position:0% +course by looking at the honeymooners +and I remember I was teaching the course + + align:start position:0% +and I remember I was teaching the course + + + align:start position:0% +and I remember I was teaching the course +in a room at Yale College Kalindi + + align:start position:0% +in a room at Yale College Kalindi + + + align:start position:0% +in a room at Yale College Kalindi +Chittenden Hall in which legendary + + align:start position:0% +Chittenden Hall in which legendary + + + align:start position:0% +Chittenden Hall in which legendary +figures had laid lectured on Shakespeare + + align:start position:0% +figures had laid lectured on Shakespeare + + + align:start position:0% +figures had laid lectured on Shakespeare +and one of these legendary professors + + align:start position:0% +and one of these legendary professors + + + align:start position:0% +and one of these legendary professors +the man who had actually hired me at + + align:start position:0% +the man who had actually hired me at + + + align:start position:0% +the man who had actually hired me at +Yale Maynard Mack of great a great + + align:start position:0% +Yale Maynard Mack of great a great + + + align:start position:0% +Yale Maynard Mack of great a great +literary scholar poaches headed and + + align:start position:0% +literary scholar poaches headed and + + + align:start position:0% +literary scholar poaches headed and +while I was teaching the honeymooners + + align:start position:0% +while I was teaching the honeymooners + + + align:start position:0% +while I was teaching the honeymooners +and then later called me into his office + + align:start position:0% +and then later called me into his office + + + align:start position:0% +and then later called me into his office +and expressed great disappointment over + + align:start position:0% +and expressed great disappointment over + + + align:start position:0% +and expressed great disappointment over +the fact that I was polluting this this + + align:start position:0% +the fact that I was polluting this this + + + align:start position:0% +the fact that I was polluting this this +environment so then I and when we then + + align:start position:0% +environment so then I and when we then + + + align:start position:0% +environment so then I and when we then +had a serious conversation and I said to + + align:start position:0% +had a serious conversation and I said to + + + align:start position:0% +had a serious conversation and I said to +him what did you what did he actually + + align:start position:0% +him what did you what did he actually + + + align:start position:0% +him what did you what did he actually +think Shakespeare's environment was and + + align:start position:0% +think Shakespeare's environment was and + + + align:start position:0% +think Shakespeare's environment was and +that was when it struck me how narrow my + + align:start position:0% +that was when it struck me how narrow my + + + align:start position:0% +that was when it struck me how narrow my +education had been because he really had + + align:start position:0% +education had been because he really had + + + align:start position:0% +education had been because he really had +not even though he was a great man and + + align:start position:0% +not even though he was a great man and + + + align:start position:0% +not even though he was a great man and +agreed he knew the history but he + + align:start position:0% +agreed he knew the history but he + + + align:start position:0% +agreed he knew the history but he +somehow had managed to disconnect the + + align:start position:0% +somehow had managed to disconnect the + + + align:start position:0% +somehow had managed to disconnect the +literary power of Shakespeare from the + + align:start position:0% +literary power of Shakespeare from the + + + align:start position:0% +literary power of Shakespeare from the +fact that it was done on this incredibly + + align:start position:0% +fact that it was done on this incredibly + + + align:start position:0% +fact that it was done on this incredibly +popular stage and it was so sensational + + align:start position:0% +popular stage and it was so sensational + + + align:start position:0% +popular stage and it was so sensational +and it was so much more like a + + align:start position:0% +and it was so much more like a + + + align:start position:0% +and it was so much more like a +television or the movies than it was + + align:start position:0% +television or the movies than it was + + + align:start position:0% +television or the movies than it was +like some process of sitting in a in a + + align:start position:0% +like some process of sitting in a in a + + + align:start position:0% +like some process of sitting in a in a +library with wood-paneled splendor + + align:start position:0% +library with wood-paneled splendor + + + align:start position:0% +library with wood-paneled splendor +reading words in silence that's not what + + align:start position:0% +reading words in silence that's not what + + + align:start position:0% +reading words in silence that's not what +Shakespeare was + + align:start position:0% +Shakespeare was + + + align:start position:0% +Shakespeare was +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +part of why we wanted to talk about + + align:start position:0% +part of why we wanted to talk about + + + align:start position:0% +part of why we wanted to talk about +professor Thor Barton's film experience + + align:start position:0% +professor Thor Barton's film experience + + + align:start position:0% +professor Thor Barton's film experience +class is because teaching film changes + + align:start position:0% +class is because teaching film changes + + + align:start position:0% +class is because teaching film changes +as technology and student life evolve + + align:start position:0% +as technology and student life evolve + + + align:start position:0% +as technology and student life evolve +I asked him what this evolution means + + align:start position:0% +I asked him what this evolution means + + + align:start position:0% +I asked him what this evolution means +for the ways in which he presents his + + align:start position:0% +for the ways in which he presents his + + + align:start position:0% +for the ways in which he presents his +materials his answer start from the very + + align:start position:0% +materials his answer start from the very + + + align:start position:0% +materials his answer start from the very +beginning when I begin the film + + align:start position:0% +beginning when I begin the film + + + align:start position:0% +beginning when I begin the film +experience I asked the students to do + + align:start position:0% +experience I asked the students to do + + + align:start position:0% +experience I asked the students to do +something they find increasingly + + align:start position:0% +something they find increasingly + + + align:start position:0% +something they find increasingly +difficult in the old days before the + + align:start position:0% +difficult in the old days before the + + + align:start position:0% +difficult in the old days before the +proliferation of smartphones and visual + + align:start position:0% +proliferation of smartphones and visual + + + align:start position:0% +proliferation of smartphones and visual +media all over the place and everyone + + align:start position:0% +media all over the place and everyone + + + align:start position:0% +media all over the place and everyone +being able to make his own video and so + + align:start position:0% +being able to make his own video and so + + + align:start position:0% +being able to make his own video and so +forth and the you know the ubiquity of + + align:start position:0% +forth and the you know the ubiquity of + + + align:start position:0% +forth and the you know the ubiquity of +DVDs before those days I was able to + + align:start position:0% +DVDs before those days I was able to + + + align:start position:0% +DVDs before those days I was able to +tell the students look we live in an + + align:start position:0% +tell the students look we live in an + + + align:start position:0% +tell the students look we live in an +audio-visual age we live in a televisual + + align:start position:0% +audio-visual age we live in a televisual + + + align:start position:0% +audio-visual age we live in a televisual +age I want you to think that stuff away + + align:start position:0% +age I want you to think that stuff away + + + align:start position:0% +age I want you to think that stuff away +I want you to get think yourself back to + + align:start position:0% +I want you to get think yourself back to + + + align:start position:0% +I want you to get think yourself back to +an age before people understood that + + align:start position:0% +an age before people understood that + + + align:start position:0% +an age before people understood that +there is such a thing as a film and + + align:start position:0% +there is such a thing as a film and + + + align:start position:0% +there is such a thing as a film and +think about the original meaning of + + align:start position:0% +think about the original meaning of + + + align:start position:0% +think about the original meaning of +movie is go back to the roots meaning + + align:start position:0% +movie is go back to the roots meaning + + + align:start position:0% +movie is go back to the roots meaning +it's a metaphor that is a dead metaphor + + align:start position:0% +it's a metaphor that is a dead metaphor + + + align:start position:0% +it's a metaphor that is a dead metaphor +for us but it actually it's it tells you + + align:start position:0% +for us but it actually it's it tells you + + + align:start position:0% +for us but it actually it's it tells you +what the most fundamental aspect of the + + align:start position:0% +what the most fundamental aspect of the + + + align:start position:0% +what the most fundamental aspect of the +movies were for the original audiences + + align:start position:0% +movies were for the original audiences + + + align:start position:0% +movies were for the original audiences +and why they were so fascinated by the + + align:start position:0% +and why they were so fascinated by the + + + align:start position:0% +and why they were so fascinated by the +capacity of this new technology to + + align:start position:0% +capacity of this new technology to + + + align:start position:0% +capacity of this new technology to +capture motion it seemed like and it was + + align:start position:0% +capture motion it seemed like and it was + + + align:start position:0% +capture motion it seemed like and it was +a tremendous new advance in technologies + + align:start position:0% +a tremendous new advance in technologies + + + align:start position:0% +a tremendous new advance in technologies +of the representation of human + + align:start position:0% +of the representation of human + + + align:start position:0% +of the representation of human +experience because it captured humans in + + align:start position:0% +experience because it captured humans in + + + align:start position:0% +experience because it captured humans in +motion it captured the movements of the + + align:start position:0% +motion it captured the movements of the + + + align:start position:0% +motion it captured the movements of the +world the first films as I try to show + + align:start position:0% +world the first films as I try to show + + + align:start position:0% +world the first films as I try to show +my students were so preoccupied by this + + align:start position:0% +my students were so preoccupied by this + + + align:start position:0% +my students were so preoccupied by this +wondrous capacity of the medium that + + align:start position:0% +wondrous capacity of the medium that + + + align:start position:0% +wondrous capacity of the medium that +it's almost the only thing they filmed + + align:start position:0% +it's almost the only thing they filmed + + + align:start position:0% +it's almost the only thing they filmed +and you can see the evolution of the + + align:start position:0% +and you can see the evolution of the + + + align:start position:0% +and you can see the evolution of the +medium embodied in the way in which + + align:start position:0% +medium embodied in the way in which + + + align:start position:0% +medium embodied in the way in which +after an initial profound fascination + + align:start position:0% +after an initial profound fascination + + + align:start position:0% +after an initial profound fascination +with the novelty of movement begins to + + align:start position:0% +with the novelty of movement begins to + + + align:start position:0% +with the novelty of movement begins to +wear off other properties of the film + + align:start position:0% +wear off other properties of the film + + + align:start position:0% +wear off other properties of the film +medium begin to be discovered so I tell + + align:start position:0% +medium begin to be discovered so I tell + + + align:start position:0% +medium begin to be discovered so I tell +my students this principle and I asked + + align:start position:0% +my students this principle and I asked + + + align:start position:0% +my students this principle and I asked +them to try to think their way back into + + align:start position:0% +them to try to think their way back into + + + align:start position:0% +them to try to think their way back into +the attitude of these first viewers who + + align:start position:0% +the attitude of these first viewers who + + + align:start position:0% +the attitude of these first viewers who +didn't know about the visual media to + + align:start position:0% +didn't know about the visual media to + + + align:start position:0% +didn't know about the visual media to +play a kind of thought experiment today + + align:start position:0% +play a kind of thought experiment today + + + align:start position:0% +play a kind of thought experiment today +it's much harder to make them play that + + align:start position:0% +it's much harder to make them play that + + + align:start position:0% +it's much harder to make them play that +experiment because I have to tell them + + align:start position:0% +experiment because I have to tell them + + + align:start position:0% +experiment because I have to tell them +as I do in that first lecture think + + align:start position:0% +as I do in that first lecture think + + + align:start position:0% +as I do in that first lecture think +away your iPad's imagine a world without + + align:start position:0% +away your iPad's imagine a world without + + + align:start position:0% +away your iPad's imagine a world without +iPads imagine a world without + + align:start position:0% +iPads imagine a world without + + + align:start position:0% +iPads imagine a world without +smartphones imagine a world without + + align:start position:0% +smartphones imagine a world without + + + align:start position:0% +smartphones imagine a world without +instant communication and of course this + + align:start position:0% +instant communication and of course this + + + align:start position:0% +instant communication and of course this +is much harder for the students to do + + align:start position:0% +is much harder for the students to do + + + align:start position:0% +is much harder for the students to do +and of course at one level they are much + + align:start position:0% +and of course at one level they are much + + + align:start position:0% +and of course at one level they are much +more capable of processing audio visual + + align:start position:0% +more capable of processing audio visual + + + align:start position:0% +more capable of processing audio visual +information than I am and then my and my + + align:start position:0% +information than I am and then my and my + + + align:start position:0% +information than I am and then my and my +parents generation and then and and all + + align:start position:0% +parents generation and then and and all + + + align:start position:0% +parents generation and then and and all +of the generations older than their + + align:start position:0% +of the generations older than their + + + align:start position:0% +of the generations older than their +because they've grown up in an + + align:start position:0% +because they've grown up in an + + + align:start position:0% +because they've grown up in an +environment in which essentially they're + + align:start position:0% +environment in which essentially they're + + + align:start position:0% +environment in which essentially they're +surrounded 24/7 by audio visual stimuli + + align:start position:0% +surrounded 24/7 by audio visual stimuli + + + align:start position:0% +surrounded 24/7 by audio visual stimuli +by audio visual signals this many people + + align:start position:0% +by audio visual signals this many people + + + align:start position:0% +by audio visual signals this many people +might see this as dangerous perhaps it + + align:start position:0% +might see this as dangerous perhaps it + + + align:start position:0% +might see this as dangerous perhaps it +is but it develops new capacities and + + align:start position:0% +is but it develops new capacities and + + + align:start position:0% +is but it develops new capacities and +the and one can see this in the history + + align:start position:0% +the and one can see this in the history + + + align:start position:0% +the and one can see this in the history +of television in which at a certain + + align:start position:0% +of television in which at a certain + + + align:start position:0% +of television in which at a certain +point there are certain kinds of + + align:start position:0% +point there are certain kinds of + + + align:start position:0% +point there are certain kinds of +television programs that become too + + align:start position:0% +television programs that become too + + + align:start position:0% +television programs that become too +complex for older generations and only + + align:start position:0% +complex for older generations and only + + + align:start position:0% +complex for older generations and only +the younger generation that was used to + + align:start position:0% +the younger generation that was used to + + + align:start position:0% +the younger generation that was used to +going to the movies and had been + + align:start position:0% +going to the movies and had been + + + align:start position:0% +going to the movies and had been +watching television and had been + + align:start position:0% +watching television and had been + + + align:start position:0% +watching television and had been +watching MTV they were able to + + align:start position:0% +watching MTV they were able to + + + align:start position:0% +watching MTV they were able to +understand this very easily + + align:start position:0% +understand this very easily + + + align:start position:0% +understand this very easily +professor Thor burns class includes a + + align:start position:0% +professor Thor burns class includes a + + + align:start position:0% +professor Thor burns class includes a +two-hour lecture with one more hour of + + align:start position:0% +two-hour lecture with one more hour of + + + align:start position:0% +two-hour lecture with one more hour of +discussion in our conversation he talked + + align:start position:0% +discussion in our conversation he talked + + + align:start position:0% +discussion in our conversation he talked +about the changing popular opinion + + align:start position:0% +about the changing popular opinion + + + align:start position:0% +about the changing popular opinion +surrounding lectures namely that their + + align:start position:0% +surrounding lectures namely that their + + + align:start position:0% +surrounding lectures namely that their +outdated and less effective than other + + align:start position:0% +outdated and less effective than other + + + align:start position:0% +outdated and less effective than other +styles of teaching in short he disagrees + + align:start position:0% +styles of teaching in short he disagrees + + + align:start position:0% +styles of teaching in short he disagrees +I'll let him explain I've thought a lot + + align:start position:0% +I'll let him explain I've thought a lot + + + align:start position:0% +I'll let him explain I've thought a lot +about what it means to lecture to + + align:start position:0% +about what it means to lecture to + + + align:start position:0% +about what it means to lecture to +undergraduates I hated bad lectures I + + align:start position:0% +undergraduates I hated bad lectures I + + + align:start position:0% +undergraduates I hated bad lectures I +thought they were the the pits of higher + + align:start position:0% +thought they were the the pits of higher + + + align:start position:0% +thought they were the the pits of higher +education and I swore to myself that if + + align:start position:0% +education and I swore to myself that if + + + align:start position:0% +education and I swore to myself that if +I became a lecturer I would never more + + align:start position:0% +I became a lecturer I would never more + + + align:start position:0% +I became a lecturer I would never more +my students that that was a worse sin + + align:start position:0% +my students that that was a worse sin + + + align:start position:0% +my students that that was a worse sin +than almost any other a teacher could + + align:start position:0% +than almost any other a teacher could + + + align:start position:0% +than almost any other a teacher could +commit was to be boring and I have also + + align:start position:0% +commit was to be boring and I have also + + + align:start position:0% +commit was to be boring and I have also +felt that in recent years especially + + align:start position:0% +felt that in recent years especially + + + align:start position:0% +felt that in recent years especially +although it's always been an + + align:start position:0% +although it's always been an + + + align:start position:0% +although it's always been an +undercurrent in education there's been a + + align:start position:0% +undercurrent in education there's been a + + + align:start position:0% +undercurrent in education there's been a +kind of growing negative feeling about + + align:start position:0% +kind of growing negative feeling about + + + align:start position:0% +kind of growing negative feeling about +lectures as if they're they're hurting + + align:start position:0% +lectures as if they're they're hurting + + + align:start position:0% +lectures as if they're they're hurting +students into a herd experience and it + + align:start position:0% +students into a herd experience and it + + + align:start position:0% +students into a herd experience and it +doesn't give them hands-on experience + + align:start position:0% +doesn't give them hands-on experience + + + align:start position:0% +doesn't give them hands-on experience +and I think intellectually that's a + + align:start position:0% +and I think intellectually that's a + + + align:start position:0% +and I think intellectually that's a +foolish perspective professors know more + + align:start position:0% +foolish perspective professors know more + + + align:start position:0% +foolish perspective professors know more +than students it's appropriate for + + align:start position:0% +than students it's appropriate for + + + align:start position:0% +than students it's appropriate for +students to listen to professors + + align:start position:0% +students to listen to professors + + + align:start position:0% +students to listen to professors +sometimes professors should take the + + align:start position:0% +sometimes professors should take the + + + align:start position:0% +sometimes professors should take the +responsibility of taught when they talk + + align:start position:0% +responsibility of taught when they talk + + + align:start position:0% +responsibility of taught when they talk +to students + + align:start position:0% +to students + + + align:start position:0% +to students +very seriously and in the in a small + + align:start position:0% +very seriously and in the in a small + + + align:start position:0% +very seriously and in the in a small +classroom they should certainly + + align:start position:0% +classroom they should certainly + + + align:start position:0% +classroom they should certainly +encourage discussion and interaction and + + align:start position:0% +encourage discussion and interaction and + + + align:start position:0% +encourage discussion and interaction and +I think at my best I'm not sure I always + + align:start position:0% +I think at my best I'm not sure I always + + + align:start position:0% +I think at my best I'm not sure I always +am at my best I know I'm not but when I + + align:start position:0% +am at my best I know I'm not but when I + + + align:start position:0% +am at my best I know I'm not but when I +am at my best I think I'm doing + + align:start position:0% +am at my best I think I'm doing + + + align:start position:0% +am at my best I think I'm doing +something that that can't be captured in + + align:start position:0% +something that that can't be captured in + + + align:start position:0% +something that that can't be captured in +printed form or couldn't be captured if + + align:start position:0% +printed form or couldn't be captured if + + + align:start position:0% +printed form or couldn't be captured if +you gave the students a transcript of + + align:start position:0% +you gave the students a transcript of + + + align:start position:0% +you gave the students a transcript of +what you had done which is that I'm + + align:start position:0% +what you had done which is that I'm + + + align:start position:0% +what you had done which is that I'm +modeling thinking I'm modeling how you + + align:start position:0% +modeling thinking I'm modeling how you + + + align:start position:0% +modeling thinking I'm modeling how you +make connections it seemed to me as I + + align:start position:0% +make connections it seemed to me as I + + + align:start position:0% +make connections it seemed to me as I +thought about the most inspiring + + align:start position:0% +thought about the most inspiring + + + align:start position:0% +thought about the most inspiring +lectures that I had as an undergraduate + + align:start position:0% +lectures that I had as an undergraduate + + + align:start position:0% +lectures that I had as an undergraduate +there was one professor I had especially + + align:start position:0% +there was one professor I had especially + + + align:start position:0% +there was one professor I had especially +he's now dead but he was a wonderfully + + align:start position:0% +he's now dead but he was a wonderfully + + + align:start position:0% +he's now dead but he was a wonderfully +inspiring man's name was Lawrence + + align:start position:0% +inspiring man's name was Lawrence + + + align:start position:0% +inspiring man's name was Lawrence +Holland his lecturer was on American + + align:start position:0% +Holland his lecturer was on American + + + align:start position:0% +Holland his lecturer was on American +literature and his strategy in lectures + + align:start position:0% +literature and his strategy in lectures + + + align:start position:0% +literature and his strategy in lectures +I've tried to copy one thing he always + + align:start position:0% +I've tried to copy one thing he always + + + align:start position:0% +I've tried to copy one thing he always +did was he presented an outline it + + align:start position:0% +did was he presented an outline it + + + align:start position:0% +did was he presented an outline it +wasn't it was not the text of the + + align:start position:0% +wasn't it was not the text of the + + + align:start position:0% +wasn't it was not the text of the +lecture but it was three or four central + + align:start position:0% +lecture but it was three or four central + + + align:start position:0% +lecture but it was three or four central +digestible points that organized the + + align:start position:0% +digestible points that organized the + + + align:start position:0% +digestible points that organized the +lecture in sequence it didn't capture + + align:start position:0% +lecture in sequence it didn't capture + + + align:start position:0% +lecture in sequence it didn't capture +the whole lecture but if you could use + + align:start position:0% +the whole lecture but if you could use + + + align:start position:0% +the whole lecture but if you could use +that sheet to organize your + + align:start position:0% +that sheet to organize your + + + align:start position:0% +that sheet to organize your +understanding of the lecture I thought + + align:start position:0% +understanding of the lecture I thought + + + align:start position:0% +understanding of the lecture I thought +that was a wonderfully helpful I found + + align:start position:0% +that was a wonderfully helpful I found + + + align:start position:0% +that was a wonderfully helpful I found +it wonderfully helpful but the both for + + align:start position:0% +it wonderfully helpful but the both for + + + align:start position:0% +it wonderfully helpful but the both for +review but also because what it showed + + align:start position:0% +review but also because what it showed + + + align:start position:0% +review but also because what it showed +me was that Professor Holland had + + align:start position:0% +me was that Professor Holland had + + + align:start position:0% +me was that Professor Holland had +planned what he was doing that he was + + align:start position:0% +planned what he was doing that he was + + + align:start position:0% +planned what he was doing that he was +presenting material to me that he had + + align:start position:0% +presenting material to me that he had + + + align:start position:0% +presenting material to me that he had +thought long about that he had organized + + align:start position:0% +thought long about that he had organized + + + align:start position:0% +thought long about that he had organized +in a serious way but the second great + + align:start position:0% +in a serious way but the second great + + + align:start position:0% +in a serious way but the second great +thing about Larry Holland's lectures was + + align:start position:0% +thing about Larry Holland's lectures was + + + align:start position:0% +thing about Larry Holland's lectures was +that they were not completely written + + align:start position:0% +that they were not completely written + + + align:start position:0% +that they were not completely written +out there were parts of them that were + + align:start position:0% +out there were parts of them that were + + + align:start position:0% +out there were parts of them that were +written out very eloquent moments often + + align:start position:0% +written out very eloquent moments often + + + align:start position:0% +written out very eloquent moments often +at the beginning at the end and I've + + align:start position:0% +at the beginning at the end and I've + + + align:start position:0% +at the beginning at the end and I've +sometimes imitated that but the greatest + + align:start position:0% +sometimes imitated that but the greatest + + + align:start position:0% +sometimes imitated that but the greatest +part of his lectures with his lecture + + align:start position:0% +part of his lectures with his lecture + + + align:start position:0% +part of his lectures with his lecture +seemed spontaneous even though he was + + align:start position:0% +seemed spontaneous even though he was + + + align:start position:0% +seemed spontaneous even though he was +following his lecture it seemed as if he + + align:start position:0% +following his lecture it seemed as if he + + + align:start position:0% +following his lecture it seemed as if he +was not he was speaking to me and I + + align:start position:0% +was not he was speaking to me and I + + + align:start position:0% +was not he was speaking to me and I +tried to capture I've never been as good + + align:start position:0% +tried to capture I've never been as good + + + align:start position:0% +tried to capture I've never been as good +as he was there was a kind of passion a + + align:start position:0% +as he was there was a kind of passion a + + + align:start position:0% +as he was there was a kind of passion a +kind of feeling in what he did and I + + align:start position:0% +kind of feeling in what he did and I + + + align:start position:0% +kind of feeling in what he did and I +realized that the another aspect of what + + align:start position:0% +realized that the another aspect of what + + + align:start position:0% +realized that the another aspect of what +he was showing me was how not just + + align:start position:0% +he was showing me was how not just + + + align:start position:0% +he was showing me was how not just +intellectually engaged but how + + align:start position:0% +intellectually engaged but how + + + align:start position:0% +intellectually engaged but how +passionate + + align:start position:0% +passionate + + + align:start position:0% +passionate +engaged how emotionally valuable + + align:start position:0% +engaged how emotionally valuable + + + align:start position:0% +engaged how emotionally valuable +studying literature could be maybe the + + align:start position:0% +studying literature could be maybe the + + + align:start position:0% +studying literature could be maybe the +most telling feature of this course is + + align:start position:0% +most telling feature of this course is + + + align:start position:0% +most telling feature of this course is +its intended outcome for students + + align:start position:0% +its intended outcome for students + + + align:start position:0% +its intended outcome for students +professor Thorburn isn't trying to + + align:start position:0% +professor Thorburn isn't trying to + + + align:start position:0% +professor Thorburn isn't trying to +create film critics or even experts in + + align:start position:0% +create film critics or even experts in + + + align:start position:0% +create film critics or even experts in +his classes his school is much more + + align:start position:0% +his classes his school is much more + + + align:start position:0% +his classes his school is much more +significant one of the ways of the study + + align:start position:0% +significant one of the ways of the study + + + align:start position:0% +significant one of the ways of the study +of literature the study of film differs + + align:start position:0% +of literature the study of film differs + + + align:start position:0% +of literature the study of film differs +from the study of technical things and + + align:start position:0% +from the study of technical things and + + + align:start position:0% +from the study of technical things and +the reason I teach it is that it belongs + + align:start position:0% +the reason I teach it is that it belongs + + + align:start position:0% +the reason I teach it is that it belongs +to everyone that it's valuable for + + align:start position:0% +to everyone that it's valuable for + + + align:start position:0% +to everyone that it's valuable for +everyone not everyone needs to know + + align:start position:0% +everyone not everyone needs to know + + + align:start position:0% +everyone not everyone needs to know +about quantum mechanics but I believe + + align:start position:0% +about quantum mechanics but I believe + + + align:start position:0% +about quantum mechanics but I believe +everyone should and if they don't I feel + + align:start position:0% +everyone should and if they don't I feel + + + align:start position:0% +everyone should and if they don't I feel +they're impoverished know how to read a + + align:start position:0% +they're impoverished know how to read a + + + align:start position:0% +they're impoverished know how to read a +good story + + align:start position:0% +good story + + + align:start position:0% +good story +enjoy plays know how to enjoy the movies + + align:start position:0% +enjoy plays know how to enjoy the movies + + + align:start position:0% +enjoy plays know how to enjoy the movies +so I feel that what I'm giving my + + align:start position:0% +so I feel that what I'm giving my + + + align:start position:0% +so I feel that what I'm giving my +students is in some sense something even + + align:start position:0% +students is in some sense something even + + + align:start position:0% +students is in some sense something even +more valuable to them because it will be + + align:start position:0% +more valuable to them because it will be + + + align:start position:0% +more valuable to them because it will be +something that they'll have with them + + align:start position:0% +something that they'll have with them + + + align:start position:0% +something that they'll have with them +for their whole lives their whole career + + align:start position:0% +for their whole lives their whole career + + + align:start position:0% +for their whole lives their whole career +one of the things MIT students sometimes + + align:start position:0% +one of the things MIT students sometimes + + + align:start position:0% +one of the things MIT students sometimes +often do not realize is that a very + + align:start position:0% +often do not realize is that a very + + + align:start position:0% +often do not realize is that a very +large number of them do not end up + + align:start position:0% +large number of them do not end up + + + align:start position:0% +large number of them do not end up +making their living in the areas in + + align:start position:0% +making their living in the areas in + + + align:start position:0% +making their living in the areas in +which they majored but all of them end + + align:start position:0% +which they majored but all of them end + + + align:start position:0% +which they majored but all of them end +up wanting to go to the movies all of + + align:start position:0% +up wanting to go to the movies all of + + + align:start position:0% +up wanting to go to the movies all of +them end up with a capacity to read and + + align:start position:0% +them end up with a capacity to read and + + + align:start position:0% +them end up with a capacity to read and +enjoy literature and I hope that coming + + align:start position:0% +enjoy literature and I hope that coming + + + align:start position:0% +enjoy literature and I hope that coming +out of my classes they'll do those + + align:start position:0% +out of my classes they'll do those + + + align:start position:0% +out of my classes they'll do those +things with greater joy and with greater + + align:start position:0% +things with greater joy and with greater + + + align:start position:0% +things with greater joy and with greater +intelligence but one thing I've thought + + align:start position:0% +intelligence but one thing I've thought + + + align:start position:0% +intelligence but one thing I've thought +about that you know I don't know I I + + align:start position:0% +about that you know I don't know I I + + + align:start position:0% +about that you know I don't know I I +don't I haven't actually said this in in + + align:start position:0% +don't I haven't actually said this in in + + + align:start position:0% +don't I haven't actually said this in in +in my courses yet but I I think implicit + + align:start position:0% +in my courses yet but I I think implicit + + + align:start position:0% +in my courses yet but I I think implicit +in my film course is an admiration for a + + align:start position:0% +in my film course is an admiration for a + + + align:start position:0% +in my film course is an admiration for a +certain kind of achievement an + + align:start position:0% +certain kind of achievement an + + + align:start position:0% +certain kind of achievement an +admiration for a certain kind of artist + + align:start position:0% +admiration for a certain kind of artist + + + align:start position:0% +admiration for a certain kind of artist +an artist like Jean Renoir the great + + align:start position:0% +an artist like Jean Renoir the great + + + align:start position:0% +an artist like Jean Renoir the great +filmmaker or Monet the great painter + + align:start position:0% +filmmaker or Monet the great painter + + + align:start position:0% +filmmaker or Monet the great painter +whose Cathedral series I often talk + + align:start position:0% +whose Cathedral series I often talk + + + align:start position:0% +whose Cathedral series I often talk +about in my teaching and I realized that + + align:start position:0% +about in my teaching and I realized that + + + align:start position:0% +about in my teaching and I realized that +I shouldn't leave it implicit because I + + align:start position:0% +I shouldn't leave it implicit because I + + + align:start position:0% +I shouldn't leave it implicit because I +want to set up as a candidate for their + + align:start position:0% +want to set up as a candidate for their + + + align:start position:0% +want to set up as a candidate for their +admiration an alternative + + align:start position:0% +admiration an alternative + + + align:start position:0% +admiration an alternative +to Wall Street an alternative to + + align:start position:0% +to Wall Street an alternative to + + + align:start position:0% +to Wall Street an alternative to +entrepreneurial genius + + align:start position:0% +entrepreneurial genius + + + align:start position:0% +entrepreneurial genius +I admire John Renoir is genius or Orson + + align:start position:0% +I admire John Renoir is genius or Orson + + + align:start position:0% +I admire John Renoir is genius or Orson +Welles is genius or James Joyce's genius + + align:start position:0% +Welles is genius or James Joyce's genius + + + align:start position:0% +Welles is genius or James Joyce's genius +universe is more than I admire what + + align:start position:0% +universe is more than I admire what + + + align:start position:0% +universe is more than I admire what +entrepreneurs do I respect what + + align:start position:0% +entrepreneurs do I respect what + + + align:start position:0% +entrepreneurs do I respect what +entrepreneurs do but I am in awe of what + + align:start position:0% +entrepreneurs do but I am in awe of what + + + align:start position:0% +entrepreneurs do but I am in awe of what +great artists do and of what great + + align:start position:0% +great artists do and of what great + + + align:start position:0% +great artists do and of what great +doctors do what while we're on the + + align:start position:0% +doctors do what while we're on the + + + align:start position:0% +doctors do what while we're on the +subject we become so preoccupied by what + + align:start position:0% +subject we become so preoccupied by what + + + align:start position:0% +subject we become so preoccupied by what +we might call commercial or financial + + align:start position:0% +we might call commercial or financial + + + align:start position:0% +we might call commercial or financial +success instead of the kind of lasting + + align:start position:0% +success instead of the kind of lasting + + + align:start position:0% +success instead of the kind of lasting +success that great art or the practice + + align:start position:0% +success that great art or the practice + + + align:start position:0% +success that great art or the practice +of medicine or the practice of Nursing + + align:start position:0% +of medicine or the practice of Nursing + + + align:start position:0% +of medicine or the practice of Nursing +or dare I say it the practice of + + align:start position:0% +or dare I say it the practice of + + + align:start position:0% +or dare I say it the practice of +teaching might also embody + + align:start position:0% + + + + align:start position:0% + +professor Thorburn shares additional + + align:start position:0% +professor Thorburn shares additional + + + align:start position:0% +professor Thorburn shares additional +thoughts on teaching the film experience + + align:start position:0% +thoughts on teaching the film experience + + + align:start position:0% +thoughts on teaching the film experience +in a series of videos within the + + align:start position:0% +in a series of videos within the + + + align:start position:0% +in a series of videos within the +instructor insight section of is OCW + + align:start position:0% +instructor insight section of is OCW + + + align:start position:0% +instructor insight section of is OCW +course you can find them at ocw.mit.edu + + align:start position:0% +course you can find them at ocw.mit.edu + + + align:start position:0% +course you can find them at ocw.mit.edu +and while you're there + + align:start position:0% +and while you're there + + + align:start position:0% +and while you're there +download the teaching resources from his + + align:start position:0% +download the teaching resources from his + + + align:start position:0% +download the teaching resources from his +course and find so many other materials + + align:start position:0% +course and find so many other materials + + + align:start position:0% +course and find so many other materials +shared by faculty across all of the + + align:start position:0% +shared by faculty across all of the + + + align:start position:0% +shared by faculty across all of the +schools at MIT + + align:start position:0% + + + + align:start position:0% + +thank you for listening we're so glad + + align:start position:0% +thank you for listening we're so glad + + + align:start position:0% +thank you for listening we're so glad +that you're tuning into what makes MIT + + align:start position:0% +that you're tuning into what makes MIT + + + align:start position:0% +that you're tuning into what makes MIT +is such an exciting place to learn + + align:start position:0% +is such an exciting place to learn + + + align:start position:0% +is such an exciting place to learn +conversations with people passionate + + align:start position:0% +conversations with people passionate + + + align:start position:0% +conversations with people passionate +about impacting the world in positive + + align:start position:0% +about impacting the world in positive + + + align:start position:0% +about impacting the world in positive +ways we hope you'll open MIT to more + + align:start position:0% +ways we hope you'll open MIT to more + + + align:start position:0% +ways we hope you'll open MIT to more +people by sharing this podcast and OCW + + align:start position:0% +people by sharing this podcast and OCW + + + align:start position:0% +people by sharing this podcast and OCW +with your own colleagues and friends + + align:start position:0% +with your own colleagues and friends + + + align:start position:0% +with your own colleagues and friends +until next time I'm Sarah Hansen from + + align:start position:0% +until next time I'm Sarah Hansen from + + + align:start position:0% +until next time I'm Sarah Hansen from +MIT OpenCourseWare + + align:start position:0% +MIT OpenCourseWare + + + align:start position:0% +MIT OpenCourseWare +[Music] \ No newline at end of file diff --git a/hqiH39PShmA.txt b/hqiH39PShmA.txt new file mode 100644 index 0000000000000000000000000000000000000000..b99fa0e8bfe9632c22625633b2682d1509327c1a --- /dev/null +++ b/hqiH39PShmA.txt @@ -0,0 +1,643 @@ +align:start position:0% + +in this recitation we're going to talk + + align:start position:0% +in this recitation we're going to talk + + + align:start position:0% +in this recitation we're going to talk +about predictive coding an emerging use + + align:start position:0% +about predictive coding an emerging use + + + align:start position:0% +about predictive coding an emerging use +of text analytics in the area of + + align:start position:0% +of text analytics in the area of + + + align:start position:0% +of text analytics in the area of +criminal justice we'll start with the + + align:start position:0% +criminal justice we'll start with the + + + align:start position:0% +criminal justice we'll start with the +story of Enron a United States energy + + align:start position:0% +story of Enron a United States energy + + + align:start position:0% +story of Enron a United States energy +company based out of Houston Texas that + + align:start position:0% +company based out of Houston Texas that + + + align:start position:0% +company based out of Houston Texas that +was involved in a number of electricity + + align:start position:0% +was involved in a number of electricity + + + align:start position:0% +was involved in a number of electricity +production and distribution markets in + + align:start position:0% +production and distribution markets in + + + align:start position:0% +production and distribution markets in +the early 2000s and Ron was a hot + + align:start position:0% +the early 2000s and Ron was a hot + + + align:start position:0% +the early 2000s and Ron was a hot +company with a market capitalization + + align:start position:0% +company with a market capitalization + + + align:start position:0% +company with a market capitalization +exceeding 60 billion dollars and Forbes + + align:start position:0% +exceeding 60 billion dollars and Forbes + + + align:start position:0% +exceeding 60 billion dollars and Forbes +magazine ranked it as the most + + align:start position:0% +magazine ranked it as the most + + + align:start position:0% +magazine ranked it as the most +innovative US company six years in a row + + align:start position:0% +innovative US company six years in a row + + + align:start position:0% +innovative US company six years in a row +now all that changed in 2001 with the + + align:start position:0% +now all that changed in 2001 with the + + + align:start position:0% +now all that changed in 2001 with the +news of widespread accounting fraud at + + align:start position:0% +news of widespread accounting fraud at + + + align:start position:0% +news of widespread accounting fraud at +the firm this massive fraud led to + + align:start position:0% +the firm this massive fraud led to + + + align:start position:0% +the firm this massive fraud led to +Enron's bankruptcy the largest ever at + + align:start position:0% +Enron's bankruptcy the largest ever at + + + align:start position:0% +Enron's bankruptcy the largest ever at +the time and led to Enron's accounting + + align:start position:0% +the time and led to Enron's accounting + + + align:start position:0% +the time and led to Enron's accounting +firm Arthur Andersen dissolving to this + + align:start position:0% +firm Arthur Andersen dissolving to this + + + align:start position:0% +firm Arthur Andersen dissolving to this +day and Ron remains a symbol of + + align:start position:0% +day and Ron remains a symbol of + + + align:start position:0% +day and Ron remains a symbol of +corporate greed and corruption + + align:start position:0% +corporate greed and corruption + + + align:start position:0% +corporate greed and corruption +now while Enron's collapse stemmed + + align:start position:0% +now while Enron's collapse stemmed + + + align:start position:0% +now while Enron's collapse stemmed +largely from accounting fraud the firm + + align:start position:0% +largely from accounting fraud the firm + + + align:start position:0% +largely from accounting fraud the firm +also faced sanctions for its involvement + + align:start position:0% +also faced sanctions for its involvement + + + align:start position:0% +also faced sanctions for its involvement +in the California electricity crisis + + align:start position:0% +in the California electricity crisis + + + align:start position:0% +in the California electricity crisis +California is the most populous state in + + align:start position:0% +California is the most populous state in + + + align:start position:0% +California is the most populous state in +the United States and in 2000 to 2001 it + + align:start position:0% +the United States and in 2000 to 2001 it + + + align:start position:0% +the United States and in 2000 to 2001 it +had a number of power blackouts despite + + align:start position:0% +had a number of power blackouts despite + + + align:start position:0% +had a number of power blackouts despite +having sufficient generating capacity it + + align:start position:0% +having sufficient generating capacity it + + + align:start position:0% +having sufficient generating capacity it +later surfaced that Enron played a key + + align:start position:0% +later surfaced that Enron played a key + + + align:start position:0% +later surfaced that Enron played a key +role in this energy crisis by + + align:start position:0% +role in this energy crisis by + + + align:start position:0% +role in this energy crisis by +artificially reducing power supply to + + align:start position:0% +artificially reducing power supply to + + + align:start position:0% +artificially reducing power supply to +spiked prices and then make me a profit + + align:start position:0% +spiked prices and then make me a profit + + + align:start position:0% +spiked prices and then make me a profit +from this market instability the Federal + + align:start position:0% +from this market instability the Federal + + + align:start position:0% +from this market instability the Federal +Energy Regulatory Commission or FERC + + align:start position:0% +Energy Regulatory Commission or FERC + + + align:start position:0% +Energy Regulatory Commission or FERC +investigated and Ron's involvement in + + align:start position:0% +investigated and Ron's involvement in + + + align:start position:0% +investigated and Ron's involvement in +the crisis and this investigation + + align:start position:0% +the crisis and this investigation + + + align:start position:0% +the crisis and this investigation +eventually led to a one point five two + + align:start position:0% +eventually led to a one point five two + + + align:start position:0% +eventually led to a one point five two +billion dollar sentiment settlement + + align:start position:0% +billion dollar sentiment settlement + + + align:start position:0% +billion dollar sentiment settlement +Burks investigation into Enron will be + + align:start position:0% +Burks investigation into Enron will be + + + align:start position:0% +Burks investigation into Enron will be +the topic of today's recitation now + + align:start position:0% +the topic of today's recitation now + + + align:start position:0% +the topic of today's recitation now +Enron was a huge company and its + + align:start position:0% +Enron was a huge company and its + + + align:start position:0% +Enron was a huge company and its +corporate servers contain millions of + + align:start position:0% +corporate servers contain millions of + + + align:start position:0% +corporate servers contain millions of +emails and other electronic files + + align:start position:0% +emails and other electronic files + + + align:start position:0% +emails and other electronic files +sifting through these documents to find + + align:start position:0% +sifting through these documents to find + + + align:start position:0% +sifting through these documents to find +the ones relevant to an investigation is + + align:start position:0% +the ones relevant to an investigation is + + + align:start position:0% +the ones relevant to an investigation is +no simple task in law this electronic + + align:start position:0% +no simple task in law this electronic + + + align:start position:0% +no simple task in law this electronic +document retrieval process is called the + + align:start position:0% +document retrieval process is called the + + + align:start position:0% +document retrieval process is called the +e-discovery problem and relevant files + + align:start position:0% +e-discovery problem and relevant files + + + align:start position:0% +e-discovery problem and relevant files +are called + + align:start position:0% +are called + + + align:start position:0% +are called +responsive documents traditionally the + + align:start position:0% +responsive documents traditionally the + + + align:start position:0% +responsive documents traditionally the +e-discovery problem has been solved by + + align:start position:0% +e-discovery problem has been solved by + + + align:start position:0% +e-discovery problem has been solved by +using a keyword search in our case + + align:start position:0% +using a keyword search in our case + + + align:start position:0% +using a keyword search in our case +perhaps searching for phrases like + + align:start position:0% +perhaps searching for phrases like + + + align:start position:0% +perhaps searching for phrases like +electricity bid or energy schedule file + + align:start position:0% +electricity bid or energy schedule file + + + align:start position:0% +electricity bid or energy schedule file +by an expensive and time-consuming + + align:start position:0% +by an expensive and time-consuming + + + align:start position:0% +by an expensive and time-consuming +manual review process in which attorneys + + align:start position:0% +manual review process in which attorneys + + + align:start position:0% +manual review process in which attorneys +read through thousands of documents to + + align:start position:0% +read through thousands of documents to + + + align:start position:0% +read through thousands of documents to +determine which ones are responsive + + align:start position:0% +determine which ones are responsive + + + align:start position:0% +determine which ones are responsive +however predictive coding is a new + + align:start position:0% +however predictive coding is a new + + + align:start position:0% +however predictive coding is a new +technique in which attorneys manually + + align:start position:0% +technique in which attorneys manually + + + align:start position:0% +technique in which attorneys manually +label some documents and then use text + + align:start position:0% +label some documents and then use text + + + align:start position:0% +label some documents and then use text +analytics models trained on the manually + + align:start position:0% +analytics models trained on the manually + + + align:start position:0% +analytics models trained on the manually +labeled documents to predict which of + + align:start position:0% +labeled documents to predict which of + + + align:start position:0% +labeled documents to predict which of +the remaining documents are responsive + + align:start position:0% +the remaining documents are responsive + + + align:start position:0% +the remaining documents are responsive +now as part of its investigation the + + align:start position:0% +now as part of its investigation the + + + align:start position:0% +now as part of its investigation the +FERC released hundreds of thousands of + + align:start position:0% +FERC released hundreds of thousands of + + + align:start position:0% +FERC released hundreds of thousands of +emails from top executives at Enron + + align:start position:0% +emails from top executives at Enron + + + align:start position:0% +emails from top executives at Enron +creating the largest publicly available + + align:start position:0% +creating the largest publicly available + + + align:start position:0% +creating the largest publicly available +set of emails today we will use this + + align:start position:0% +set of emails today we will use this + + + align:start position:0% +set of emails today we will use this +data set called the Enron corpus to + + align:start position:0% +data set called the Enron corpus to + + + align:start position:0% +data set called the Enron corpus to +perform predictive coding in this + + align:start position:0% +perform predictive coding in this + + + align:start position:0% +perform predictive coding in this +recitation our data set contains just + + align:start position:0% +recitation our data set contains just + + + align:start position:0% +recitation our data set contains just +two fields email which is the text of + + align:start position:0% +two fields email which is the text of + + + align:start position:0% +two fields email which is the text of +the email in question and responsive + + align:start position:0% +the email in question and responsive + + + align:start position:0% +the email in question and responsive +which is whether the email relates to + + align:start position:0% +which is whether the email relates to + + + align:start position:0% +which is whether the email relates to +energy schedules or bids the labels for + + align:start position:0% +energy schedules or bids the labels for + + + align:start position:0% +energy schedules or bids the labels for +these emails were made by attorneys as + + align:start position:0% +these emails were made by attorneys as + + + align:start position:0% +these emails were made by attorneys as +part of the 2010 text retrieval + + align:start position:0% +part of the 2010 text retrieval + + + align:start position:0% +part of the 2010 text retrieval +conference legal track a predictive + + align:start position:0% +conference legal track a predictive + + + align:start position:0% +conference legal track a predictive +coding competition \ No newline at end of file diff --git a/iB6SuG7wh5U.txt b/iB6SuG7wh5U.txt new file mode 100644 index 0000000000000000000000000000000000000000..df8c390875df9c9fc2a4c678a080ba64ce6f60a6 --- /dev/null +++ b/iB6SuG7wh5U.txt @@ -0,0 +1,15979 @@ +align:start position:0% + +the following content is provided by mit + + align:start position:0% +the following content is provided by mit + + + align:start position:0% +the following content is provided by mit +opencourseware under a creative commons + + align:start position:0% +opencourseware under a creative commons + + + align:start position:0% +opencourseware under a creative commons +license + + align:start position:0% +license + + + align:start position:0% +license +additional information about our license + + align:start position:0% +additional information about our license + + + align:start position:0% +additional information about our license +and mit opencourseware in general is + + align:start position:0% +and mit opencourseware in general is + + + align:start position:0% +and mit opencourseware in general is +available at ocw.mit.edu + + align:start position:0% + + + + align:start position:0% + +see what i have in mind today + + align:start position:0% + + + + align:start position:0% + +uh + + align:start position:0% +uh + + + align:start position:0% +uh +is to + + align:start position:0% + + + + align:start position:0% + +make a an assignment + + align:start position:0% + + + + align:start position:0% + +that will be due + + align:start position:0% +that will be due + + + align:start position:0% +that will be due +tuesday + + align:start position:0% +tuesday + + + align:start position:0% +tuesday +now here's what i want to do with that + + align:start position:0% +now here's what i want to do with that + + + align:start position:0% +now here's what i want to do with that +assignment + + align:start position:0% +assignment + + + align:start position:0% +assignment +i want you to write up an analysis of + + align:start position:0% +i want you to write up an analysis of + + + align:start position:0% +i want you to write up an analysis of +the a7d case + + align:start position:0% + + + + align:start position:0% + +but + + align:start position:0% +but + + + align:start position:0% +but +i want you to allow something um + + align:start position:0% +i want you to allow something um + + + align:start position:0% +i want you to allow something um +that + + align:start position:0% +that + + + align:start position:0% +that +uh isn't entirely scholarly it won't + + align:start position:0% +uh isn't entirely scholarly it won't + + + align:start position:0% +uh isn't entirely scholarly it won't +sound entirely scholarly to you at first + + align:start position:0% +sound entirely scholarly to you at first + + + align:start position:0% +sound entirely scholarly to you at first +i want to micromanage + + align:start position:0% +i want to micromanage + + + align:start position:0% +i want to micromanage +this homework assignment i want to tell + + align:start position:0% +this homework assignment i want to tell + + + align:start position:0% +this homework assignment i want to tell +you exactly what i want done all right + + align:start position:0% +you exactly what i want done all right + + + align:start position:0% +you exactly what i want done all right +now the reason for that is + + align:start position:0% +now the reason for that is + + + align:start position:0% +now the reason for that is +that once you see what i think is a good + + align:start position:0% +that once you see what i think is a good + + + align:start position:0% +that once you see what i think is a good +way to lay out something + + align:start position:0% +way to lay out something + + + align:start position:0% +way to lay out something +now you can start talking about how you + + align:start position:0% +now you can start talking about how you + + + align:start position:0% +now you can start talking about how you +want to lay it out + + align:start position:0% +want to lay it out + + + align:start position:0% +want to lay it out +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and uh then you can start talking to me + + align:start position:0% +and uh then you can start talking to me + + + align:start position:0% +and uh then you can start talking to me +about + + align:start position:0% +about + + + align:start position:0% +about +um that you want to lay it out a + + align:start position:0% +um that you want to lay it out a + + + align:start position:0% +um that you want to lay it out a +different way how can i respond to that + + align:start position:0% +different way how can i respond to that + + + align:start position:0% +different way how can i respond to that +and that kind of thing but let's see it + + align:start position:0% +and that kind of thing but let's see it + + + align:start position:0% +and that kind of thing but let's see it +one way first + + align:start position:0% +one way first + + + align:start position:0% +one way first +for and tear it up + + align:start position:0% +for and tear it up + + + align:start position:0% +for and tear it up +okay and when you turn that thing in + + align:start position:0% +okay and when you turn that thing in + + + align:start position:0% +okay and when you turn that thing in +tuesday + + align:start position:0% +tuesday + + + align:start position:0% +tuesday +um + + align:start position:0% + + + + align:start position:0% + +you'll have a format and some ideas that + + align:start position:0% +you'll have a format and some ideas that + + + align:start position:0% +you'll have a format and some ideas that +just laid out + + align:start position:0% +just laid out + + + align:start position:0% +just laid out +okay + + align:start position:0% + + + + align:start position:0% + +so my philosophy is + + align:start position:0% + + + + align:start position:0% + +in a classroom + + align:start position:0% +in a classroom + + + align:start position:0% +in a classroom +imitate + + align:start position:0% +imitate + + + align:start position:0% +imitate +then liberate + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +all right + + align:start position:0% +all right + + + align:start position:0% +all right +now what i want to do today is to is + + align:start position:0% +now what i want to do today is to is + + + align:start position:0% +now what i want to do today is to is +actually just to lay out this + + align:start position:0% +actually just to lay out this + + + align:start position:0% +actually just to lay out this +this um + + align:start position:0% +this um + + + align:start position:0% +this um +this analysis + + align:start position:0% + + + + align:start position:0% + +then at the end then i want to discuss + + align:start position:0% +then at the end then i want to discuss + + + align:start position:0% +then at the end then i want to discuss +to some extent + + align:start position:0% +to some extent + + + align:start position:0% +to some extent +this movie + + align:start position:0% +this movie + + + align:start position:0% +this movie +and then i want to deal with some um + + align:start position:0% +and then i want to deal with some um + + + align:start position:0% +and then i want to deal with some um +pedagogic issues i've got the + + align:start position:0% +pedagogic issues i've got the + + + align:start position:0% +pedagogic issues i've got the +percentages for the grades laid out all + + align:start position:0% +percentages for the grades laid out all + + + align:start position:0% +percentages for the grades laid out all +of that okay so give me a uh + + align:start position:0% +of that okay so give me a uh + + + align:start position:0% +of that okay so give me a uh +15 minute high sign before the class is + + align:start position:0% +15 minute high sign before the class is + + + align:start position:0% +15 minute high sign before the class is +over that'll give me five minutes to + + align:start position:0% +over that'll give me five minutes to + + + align:start position:0% +over that'll give me five minutes to +stop and 10 minutes to do + + align:start position:0% +stop and 10 minutes to do + + + align:start position:0% +stop and 10 minutes to do +that + + align:start position:0% +that + + + align:start position:0% +that +okay + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +you see this all right + + align:start position:0% +you see this all right + + + align:start position:0% +you see this all right +okay + + align:start position:0% + + + + align:start position:0% + +uh + + align:start position:0% + + + + align:start position:0% + +first thing i'd like you to do in this + + align:start position:0% +first thing i'd like you to do in this + + + align:start position:0% +first thing i'd like you to do in this +homework assignment is to state your + + align:start position:0% +homework assignment is to state your + + + align:start position:0% +homework assignment is to state your +purpose + + align:start position:0% + + + + align:start position:0% + +then state your objectives those are the + + align:start position:0% +then state your objectives those are the + + + align:start position:0% +then state your objectives those are the +main parts + + align:start position:0% +main parts + + + align:start position:0% +main parts +of the paper + + align:start position:0% +of the paper + + + align:start position:0% +of the paper +that will develop + + align:start position:0% + + + + align:start position:0% + +the + + align:start position:0% +the + + + align:start position:0% +the +purpose + + align:start position:0% + + + + align:start position:0% + +then + + align:start position:0% +then + + + align:start position:0% +then +i want you to give me a rationale + + align:start position:0% + + + + align:start position:0% + +that is why you're doing it why you're + + align:start position:0% +that is why you're doing it why you're + + + align:start position:0% +that is why you're doing it why you're +setting it up the way you're doing it + + align:start position:0% +setting it up the way you're doing it + + + align:start position:0% +setting it up the way you're doing it +and + + align:start position:0% +and + + + align:start position:0% +and +then lastly + + align:start position:0% + + + + align:start position:0% + +i want you to tell me + + align:start position:0% +i want you to tell me + + + align:start position:0% +i want you to tell me +write down tell me something about the + + align:start position:0% +write down tell me something about the + + + align:start position:0% +write down tell me something about the +scope of your + + align:start position:0% +scope of your + + + align:start position:0% +scope of your +of your uh analysis now here's the + + align:start position:0% +of your uh analysis now here's the + + + align:start position:0% +of your uh analysis now here's the +beauty of this + + align:start position:0% +beauty of this + + + align:start position:0% +beauty of this +this tells you what we're going to do + + align:start position:0% +this tells you what we're going to do + + + align:start position:0% +this tells you what we're going to do +what you're going to do this tells me + + align:start position:0% +what you're going to do this tells me + + + align:start position:0% +what you're going to do this tells me +what you are going to do + + align:start position:0% +what you are going to do + + + align:start position:0% +what you are going to do +and of all the things that come to my + + align:start position:0% +and of all the things that come to my + + + align:start position:0% +and of all the things that come to my +mind when you've told me what you're + + align:start position:0% +mind when you've told me what you're + + + align:start position:0% +mind when you've told me what you're +going to do you've got to tell me what + + align:start position:0% +going to do you've got to tell me what + + + align:start position:0% +going to do you've got to tell me what +it is that you're not that not going to + + align:start position:0% +it is that you're not that not going to + + + align:start position:0% +it is that you're not that not going to +do + + align:start position:0% + + + + align:start position:0% + +okay you see the metaphysics in that + + align:start position:0% +okay you see the metaphysics in that + + + align:start position:0% +okay you see the metaphysics in that +you say what a thing is and then to + + align:start position:0% +you say what a thing is and then to + + + align:start position:0% +you say what a thing is and then to +sharpen your meaning you say what it + + align:start position:0% +sharpen your meaning you say what it + + + align:start position:0% +sharpen your meaning you say what it +isn't + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +then + + align:start position:0% +then + + + align:start position:0% +then +the second thing is + + align:start position:0% +the second thing is + + + align:start position:0% +the second thing is +to lay out your argument + + align:start position:0% + + + + align:start position:0% + +by + + align:start position:0% + + + + align:start position:0% + +categories of objectives + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and then at the end + + align:start position:0% + + + + align:start position:0% + +give me a summary + + align:start position:0% + + + + align:start position:0% + +and conclusions + + align:start position:0% + + + + align:start position:0% + +basically what you want to do is to tell + + align:start position:0% +basically what you want to do is to tell + + + align:start position:0% +basically what you want to do is to tell +me + + align:start position:0% +me + + + align:start position:0% +me +uh did you fulfill your purpose + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +now + + align:start position:0% +now + + + align:start position:0% +now +what i want you to do in this purpose + + align:start position:0% +what i want you to do in this purpose + + + align:start position:0% +what i want you to do in this purpose +here + + align:start position:0% +here + + + align:start position:0% +here +is to say that you want to + + align:start position:0% +is to say that you want to + + + align:start position:0% +is to say that you want to +do a moral analysis + + align:start position:0% +do a moral analysis + + + align:start position:0% +do a moral analysis +of the a7d case + + align:start position:0% + + + + align:start position:0% + +and the scope is + + align:start position:0% +and the scope is + + + align:start position:0% +and the scope is +that you're going to do that analysis + + align:start position:0% +that you're going to do that analysis + + + align:start position:0% +that you're going to do that analysis +twice + + align:start position:0% +twice + + + align:start position:0% +twice +one using a utilitarian + + align:start position:0% +one using a utilitarian + + + align:start position:0% +one using a utilitarian +utilitarian + + align:start position:0% +utilitarian + + + align:start position:0% +utilitarian +analysis + + align:start position:0% +analysis + + + align:start position:0% +analysis +and the other one is to use what's + + align:start position:0% +and the other one is to use what's + + + align:start position:0% +and the other one is to use what's +called a deontological + + align:start position:0% +called a deontological + + + align:start position:0% +called a deontological +analysis + + align:start position:0% + + + + align:start position:0% + +okay so we're going to use uh mil and + + align:start position:0% +okay so we're going to use uh mil and + + + align:start position:0% +okay so we're going to use uh mil and +kant + + align:start position:0% + + + + align:start position:0% + +in your conclusions + + align:start position:0% +in your conclusions + + + align:start position:0% +in your conclusions +i want you to evaluate both methods + + align:start position:0% +i want you to evaluate both methods + + + align:start position:0% +i want you to evaluate both methods +relative to the a7d case + + align:start position:0% +relative to the a7d case + + + align:start position:0% +relative to the a7d case +okay + + align:start position:0% +okay + + + align:start position:0% +okay +now i can tell you what you might want + + align:start position:0% +now i can tell you what you might want + + + align:start position:0% +now i can tell you what you might want +to put in there + + align:start position:0% +to put in there + + + align:start position:0% +to put in there +that you can see already + + align:start position:0% +that you can see already + + + align:start position:0% +that you can see already +and that is + + align:start position:0% +and that is + + + align:start position:0% +and that is +that one of the problems you're going to + + align:start position:0% +that one of the problems you're going to + + + align:start position:0% +that one of the problems you're going to +have + + align:start position:0% +have + + + align:start position:0% +have +with the utilitarian approach + + align:start position:0% +with the utilitarian approach + + + align:start position:0% +with the utilitarian approach +as applied to the a7d case is + + align:start position:0% + + + + align:start position:0% + +that nobody got hurt + + align:start position:0% + + + + align:start position:0% + +okay so you're going to have to tell me + + align:start position:0% +okay so you're going to have to tell me + + + align:start position:0% +okay so you're going to have to tell me +is that a powerful method relative to + + align:start position:0% +is that a powerful method relative to + + + align:start position:0% +is that a powerful method relative to +this + + align:start position:0% +this + + + align:start position:0% +this +case all right + + align:start position:0% +case all right + + + align:start position:0% +case all right +uh one of the problems you're going to + + align:start position:0% +uh one of the problems you're going to + + + align:start position:0% +uh one of the problems you're going to +find with the uh + + align:start position:0% +find with the uh + + + align:start position:0% +find with the uh +deontological approach + + align:start position:0% + + + + align:start position:0% + +i is that + + align:start position:0% +i is that + + + align:start position:0% +i is that +you're going to find it hard to say one + + align:start position:0% +you're going to find it hard to say one + + + align:start position:0% +you're going to find it hard to say one +should never lie about anything + + align:start position:0% + + + + align:start position:0% + +because you're going to have conflicts + + align:start position:0% +because you're going to have conflicts + + + align:start position:0% +because you're going to have conflicts +with + + align:start position:0% +with + + + align:start position:0% +with +uh telling the truth all of the time + + align:start position:0% +uh telling the truth all of the time + + + align:start position:0% +uh telling the truth all of the time +we're going to have to ask ourselves is + + align:start position:0% +we're going to have to ask ourselves is + + + align:start position:0% +we're going to have to ask ourselves is +that possible in real life + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +all right + + align:start position:0% +all right + + + align:start position:0% +all right +now + + align:start position:0% +now + + + align:start position:0% +now +in your + + align:start position:0% +in your + + + align:start position:0% +in your +back matter + + align:start position:0% + + + + align:start position:0% + +of course you're going to have what + + align:start position:0% +of course you're going to have what + + + align:start position:0% +of course you're going to have what +references + + align:start position:0% + + + + align:start position:0% + +all right + + align:start position:0% +all right + + + align:start position:0% +all right +i would like to see at least one + + align:start position:0% +i would like to see at least one + + + align:start position:0% +i would like to see at least one +reference + + align:start position:0% +reference + + + align:start position:0% +reference +it's not this book + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and + + align:start position:0% +and + + + align:start position:0% +and +lastly this is a little uh something new + + align:start position:0% + + + + align:start position:0% + +i haven't lectured on this but i this + + align:start position:0% +i haven't lectured on this but i this + + + align:start position:0% +i haven't lectured on this but i this +can be pedestrian + + align:start position:0% +can be pedestrian + + + align:start position:0% +can be pedestrian +uh and that is to take what you have + + align:start position:0% +uh and that is to take what you have + + + align:start position:0% +uh and that is to take what you have +done + + align:start position:0% +done + + + align:start position:0% +done +and see if you can analyze your paper + + align:start position:0% +and see if you can analyze your paper + + + align:start position:0% +and see if you can analyze your paper +in storied terms + + align:start position:0% +in storied terms + + + align:start position:0% +in storied terms +does it have a beginning does it have a + + align:start position:0% +does it have a beginning does it have a + + + align:start position:0% +does it have a beginning does it have a +middle does it have an end + + align:start position:0% + + + + align:start position:0% + +does it make a point + + align:start position:0% + + + + align:start position:0% + +uh look where i'm pointing + + align:start position:0% +uh look where i'm pointing + + + align:start position:0% +uh look where i'm pointing +does it make a point + + align:start position:0% +does it make a point + + + align:start position:0% +does it make a point +is there a point of view + + align:start position:0% + + + + align:start position:0% + +okay remember from um + + align:start position:0% +okay remember from um + + + align:start position:0% +okay remember from um +from uh moby dick + + align:start position:0% +from uh moby dick + + + align:start position:0% +from uh moby dick +does anybody remember the first sentence + + align:start position:0% +does anybody remember the first sentence + + + align:start position:0% +does anybody remember the first sentence +in moby dick + + align:start position:0% +in moby dick + + + align:start position:0% +in moby dick +call me ishmael + + align:start position:0% +call me ishmael + + + align:start position:0% +call me ishmael +tells you what point of view you're + + align:start position:0% +tells you what point of view you're + + + align:start position:0% +tells you what point of view you're +looking at the story from + + align:start position:0% +looking at the story from + + + align:start position:0% +looking at the story from +you can see that if it was somebody else + + align:start position:0% +you can see that if it was somebody else + + + align:start position:0% +you can see that if it was somebody else +the story would be played out a little + + align:start position:0% +the story would be played out a little + + + align:start position:0% +the story would be played out a little +bit differently ahab would tell a + + align:start position:0% +bit differently ahab would tell a + + + align:start position:0% +bit differently ahab would tell a +different story with me + + align:start position:0% +different story with me + + + align:start position:0% +different story with me +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so uh give me your point of view + + align:start position:0% +so uh give me your point of view + + + align:start position:0% +so uh give me your point of view +and give me your voice is it first + + align:start position:0% +and give me your voice is it first + + + align:start position:0% +and give me your voice is it first +person second person third person + + align:start position:0% + + + + align:start position:0% + +and then put anything else in there that + + align:start position:0% +and then put anything else in there that + + + align:start position:0% +and then put anything else in there that +you can tell me + + align:start position:0% +you can tell me + + + align:start position:0% +you can tell me +about + + align:start position:0% +about + + + align:start position:0% +about +how + + align:start position:0% +how + + + align:start position:0% +how +uh what you have just done + + align:start position:0% +uh what you have just done + + + align:start position:0% +uh what you have just done +can be looked at as a story + + align:start position:0% +can be looked at as a story + + + align:start position:0% +can be looked at as a story +now that gets you ready for something + + align:start position:0% +now that gets you ready for something + + + align:start position:0% +now that gets you ready for something +we're going to cover later + + align:start position:0% +we're going to cover later + + + align:start position:0% +we're going to cover later +okay + + align:start position:0% +okay + + + align:start position:0% +okay +what i would like to do now unless you + + align:start position:0% +what i would like to do now unless you + + + align:start position:0% +what i would like to do now unless you +have any questions let me see if you got + + align:start position:0% +have any questions let me see if you got + + + align:start position:0% +have any questions let me see if you got +any questions that's what + + align:start position:0% +any questions that's what + + + align:start position:0% +any questions that's what +any questions yes + + align:start position:0% + + + + align:start position:0% + +two sequential sections one with the + + align:start position:0% +two sequential sections one with the + + + align:start position:0% +two sequential sections one with the +first analysis and one is the second + + align:start position:0% +first analysis and one is the second + + + align:start position:0% +first analysis and one is the second +analysis as opposed to + + align:start position:0% +analysis as opposed to + + + align:start position:0% +analysis as opposed to +as opposed to like + + align:start position:0% +as opposed to like + + + align:start position:0% +as opposed to like +parallel + + align:start position:0% +parallel + + + align:start position:0% +parallel +um + + align:start position:0% +um + + + align:start position:0% +um +oh you mean + + align:start position:0% +oh you mean + + + align:start position:0% +oh you mean +in one paragraph + + align:start position:0% +in one paragraph + + + align:start position:0% +in one paragraph +contrasting the methods that's your + + align:start position:0% +contrasting the methods that's your + + + align:start position:0% +contrasting the methods that's your +style + + align:start position:0% +style + + + align:start position:0% +style +no no it's not i mean i could do it + + align:start position:0% +no no it's not i mean i could do it + + + align:start position:0% +no no it's not i mean i could do it +either way i'm just trying to get a + + align:start position:0% +either way i'm just trying to get a + + + align:start position:0% +either way i'm just trying to get a +clearer picture you decide that okay you + + align:start position:0% +clearer picture you decide that okay you + + + align:start position:0% +clearer picture you decide that okay you +just said how you want to do it now i + + align:start position:0% +just said how you want to do it now i + + + align:start position:0% +just said how you want to do it now i +think that in these objectives one of + + align:start position:0% +think that in these objectives one of + + + align:start position:0% +think that in these objectives one of +the things you want to do is to state + + align:start position:0% +the things you want to do is to state + + + align:start position:0% +the things you want to do is to state +the case + + align:start position:0% +the case + + + align:start position:0% +the case +a summary of the a7b case + + align:start position:0% +a summary of the a7b case + + + align:start position:0% +a summary of the a7b case +okay so you want the facts + + align:start position:0% +okay so you want the facts + + + align:start position:0% +okay so you want the facts +then so that might be objective one + + align:start position:0% +then so that might be objective one + + + align:start position:0% +then so that might be objective one +objective two + + align:start position:0% +objective two + + + align:start position:0% +objective two +would be a utilitarian analysis + + align:start position:0% +would be a utilitarian analysis + + + align:start position:0% +would be a utilitarian analysis +i tell you what let's keep them separate + + align:start position:0% +i tell you what let's keep them separate + + + align:start position:0% +i tell you what let's keep them separate +i change that let's keep them separate + + align:start position:0% +i change that let's keep them separate + + + align:start position:0% +i change that let's keep them separate +objective two will be utilitarian + + align:start position:0% +objective two will be utilitarian + + + align:start position:0% +objective two will be utilitarian +objective three will be uh d'angelo + + align:start position:0% + + + + align:start position:0% + +so uh + + align:start position:0% +so uh + + + align:start position:0% +so uh +you may feel compelled to put in another + + align:start position:0% +you may feel compelled to put in another + + + align:start position:0% +you may feel compelled to put in another +objective but i think the three will do + + align:start position:0% + + + + align:start position:0% + +summary of the case + + align:start position:0% +summary of the case + + + align:start position:0% +summary of the case +analysis one analysis two + + align:start position:0% +analysis one analysis two + + + align:start position:0% +analysis one analysis two +okay all right + + align:start position:0% +okay all right + + + align:start position:0% +okay all right +uh i would expect something like this + + align:start position:0% +uh i would expect something like this + + + align:start position:0% +uh i would expect something like this +the whole thing + + align:start position:0% +the whole thing + + + align:start position:0% +the whole thing +to be about + + align:start position:0% +to be about + + + align:start position:0% +to be about +three pages + + align:start position:0% +three pages + + + align:start position:0% +three pages +okay + + align:start position:0% +okay + + + align:start position:0% +okay +now if you get two pages and can't think + + align:start position:0% +now if you get two pages and can't think + + + align:start position:0% +now if you get two pages and can't think +of anything else in put in there please + + align:start position:0% +of anything else in put in there please + + + align:start position:0% +of anything else in put in there please +don't + + align:start position:0% +don't + + + align:start position:0% +don't +put any uh + + align:start position:0% +put any uh + + + align:start position:0% +put any uh +thing else in there + + align:start position:0% +thing else in there + + + align:start position:0% +thing else in there +if it goes over + + align:start position:0% +if it goes over + + + align:start position:0% +if it goes over +five pages submit it if it goes to ten + + align:start position:0% +five pages submit it if it goes to ten + + + align:start position:0% +five pages submit it if it goes to ten +pages + + align:start position:0% +pages + + + align:start position:0% +pages +we got a problem + + align:start position:0% + + + + align:start position:0% + +uh + + align:start position:0% +uh + + + align:start position:0% +uh +if + + align:start position:0% +if + + + align:start position:0% +if +talk to me about it + + align:start position:0% +talk to me about it + + + align:start position:0% +talk to me about it +uh it might be something that you didn't + + align:start position:0% +uh it might be something that you didn't + + + align:start position:0% +uh it might be something that you didn't +need to say but if you really feel + + align:start position:0% +need to say but if you really feel + + + align:start position:0% +need to say but if you really feel +compelled to say ten pages worth of + + align:start position:0% +compelled to say ten pages worth of + + + align:start position:0% +compelled to say ten pages worth of +stuff then fine the only thing that was + + align:start position:0% +stuff then fine the only thing that was + + + align:start position:0% +stuff then fine the only thing that was +really going to irritate me about 10 + + align:start position:0% +really going to irritate me about 10 + + + align:start position:0% +really going to irritate me about 10 +pages is if you download nine pages of + + align:start position:0% +pages is if you download nine pages of + + + align:start position:0% +pages is if you download nine pages of +it + + align:start position:0% +it + + + align:start position:0% +it +i mean if you're writing out of your + + align:start position:0% +i mean if you're writing out of your + + + align:start position:0% +i mean if you're writing out of your +heart + + align:start position:0% +heart + + + align:start position:0% +heart +and i'll know the difference + + align:start position:0% +and i'll know the difference + + + align:start position:0% +and i'll know the difference +okay + + align:start position:0% +okay + + + align:start position:0% +okay +then we need to talk about it + + align:start position:0% +then we need to talk about it + + + align:start position:0% +then we need to talk about it +but um + + align:start position:0% +but um + + + align:start position:0% +but um +and i'm going to grade this but i'm + + align:start position:0% +and i'm going to grade this but i'm + + + align:start position:0% +and i'm going to grade this but i'm +going to like i said i'm going to + + align:start position:0% +going to like i said i'm going to + + + align:start position:0% +going to like i said i'm going to +micromanage this + + align:start position:0% +micromanage this + + + align:start position:0% +micromanage this +this this first one there's only one + + align:start position:0% +this this first one there's only one + + + align:start position:0% +this this first one there's only one +okay + + align:start position:0% +okay + + + align:start position:0% +okay +after references + + align:start position:0% +after references + + + align:start position:0% +after references +are you hoping that we'll look more into + + align:start position:0% +are you hoping that we'll look more into + + + align:start position:0% +are you hoping that we'll look more into +the facts of the case or good question + + align:start position:0% +the facts of the case or good question + + + align:start position:0% +the facts of the case or good question +the + + align:start position:0% +the + + + align:start position:0% +the +deontological and + + align:start position:0% +deontological and + + + align:start position:0% +deontological and +i'm looking up + + align:start position:0% +i'm looking up + + + align:start position:0% +i'm looking up +yes + + align:start position:0% +yes + + + align:start position:0% +yes +uh now what i'm getting ready to do now + + align:start position:0% +uh now what i'm getting ready to do now + + + align:start position:0% +uh now what i'm getting ready to do now +is to go more deeply into those methods + + align:start position:0% +is to go more deeply into those methods + + + align:start position:0% +is to go more deeply into those methods +now look at chapter six + + align:start position:0% + + + + align:start position:0% + +uh actually when i say look at chapter + + align:start position:0% +uh actually when i say look at chapter + + + align:start position:0% +uh actually when i say look at chapter +six that's not what i mean + + align:start position:0% +six that's not what i mean + + + align:start position:0% +six that's not what i mean +look at the table of contents + + align:start position:0% +look at the table of contents + + + align:start position:0% +look at the table of contents +and look at the citations chapter six + + align:start position:0% +and look at the citations chapter six + + + align:start position:0% +and look at the citations chapter six +okay what's the title + + align:start position:0% +okay what's the title + + + align:start position:0% +okay what's the title +honestly integrity + + align:start position:0% +honestly integrity + + + align:start position:0% +honestly integrity +all right that's not what i want okay + + align:start position:0% +all right that's not what i want okay + + + align:start position:0% +all right that's not what i want okay +i've got uh + + align:start position:0% +i've got uh + + + align:start position:0% +i've got uh +i was looking at the old version + + align:start position:0% +i was looking at the old version + + + align:start position:0% +i was looking at the old version +of this book + + align:start position:0% +of this book + + + align:start position:0% +of this book +and + + align:start position:0% +and + + + align:start position:0% +and +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +there was a there's a section called um + + align:start position:0% + + + + align:start position:0% + +uh which is chapter six called tests in + + align:start position:0% +uh which is chapter six called tests in + + + align:start position:0% +uh which is chapter six called tests in +moral problem solving do you have a + + align:start position:0% +moral problem solving do you have a + + + align:start position:0% +moral problem solving do you have a +chapter like that + + align:start position:0% +chapter like that + + + align:start position:0% +chapter like that +we have methods for moral problem + + align:start position:0% +we have methods for moral problem + + + align:start position:0% +we have methods for moral problem +solving what's the one right after that + + align:start position:0% +solving what's the one right after that + + + align:start position:0% +solving what's the one right after that +organizing principles + + align:start position:0% + + + + align:start position:0% + +that's the one so it's chapter four + + align:start position:0% +that's the one so it's chapter four + + + align:start position:0% +that's the one so it's chapter four +all right + + align:start position:0% +all right + + + align:start position:0% +all right +uh and chapter four + + align:start position:0% + + + + align:start position:0% + +what what they call respect for persons + + align:start position:0% +what what they call respect for persons + + + align:start position:0% +what what they call respect for persons +is kant's + + align:start position:0% +is kant's + + + align:start position:0% +is kant's +kind is one particular case + + align:start position:0% +kind is one particular case + + + align:start position:0% +kind is one particular case +but is the deontological approach + + align:start position:0% +but is the deontological approach + + + align:start position:0% +but is the deontological approach +and then utilitarianism i think they + + align:start position:0% +and then utilitarianism i think they + + + align:start position:0% +and then utilitarianism i think they +spell it out + + align:start position:0% +spell it out + + + align:start position:0% +spell it out +right there + + align:start position:0% +right there + + + align:start position:0% +right there +so but i'm going to cover i'm going to + + align:start position:0% +so but i'm going to cover i'm going to + + + align:start position:0% +so but i'm going to cover i'm going to +cover that material + + align:start position:0% +cover that material + + + align:start position:0% +cover that material +okay + + align:start position:0% +okay + + + align:start position:0% +okay +but i'm going to cover it in a way that + + align:start position:0% +but i'm going to cover it in a way that + + + align:start position:0% +but i'm going to cover it in a way that +i think + + align:start position:0% +i think + + + align:start position:0% +i think +um + + align:start position:0% +um + + + align:start position:0% +um +makes best sense for me as a teacher + + align:start position:0% +makes best sense for me as a teacher + + + align:start position:0% +makes best sense for me as a teacher +okay + + align:start position:0% +okay + + + align:start position:0% +okay +particularly because there's some + + align:start position:0% +particularly because there's some + + + align:start position:0% +particularly because there's some +subtleties in this + + align:start position:0% +subtleties in this + + + align:start position:0% +subtleties in this +in uh this material that i think that uh + + align:start position:0% +in uh this material that i think that uh + + + align:start position:0% +in uh this material that i think that uh +you ought to pick up and secondly + + align:start position:0% +you ought to pick up and secondly + + + align:start position:0% +you ought to pick up and secondly +because + + align:start position:0% +because + + + align:start position:0% +because +uh + + align:start position:0% + + + + align:start position:0% + +most most philosophers complain that + + align:start position:0% +most most philosophers complain that + + + align:start position:0% +most most philosophers complain that +kant is very hard to understand + + align:start position:0% +kant is very hard to understand + + + align:start position:0% +kant is very hard to understand +now not all philosophers believe he's + + align:start position:0% +now not all philosophers believe he's + + + align:start position:0% +now not all philosophers believe he's +hard to understand + + align:start position:0% +hard to understand + + + align:start position:0% +hard to understand +british philosophers believe he's hard + + align:start position:0% +british philosophers believe he's hard + + + align:start position:0% +british philosophers believe he's hard +to believe but they they they think he's + + align:start position:0% +to believe but they they they think he's + + + align:start position:0% +to believe but they they they think he's +impossible to understand because they + + align:start position:0% +impossible to understand because they + + + align:start position:0% +impossible to understand because they +don't they don't see it + + align:start position:0% +don't they don't see it + + + align:start position:0% +don't they don't see it +right so you've got to ask the germans + + align:start position:0% +right so you've got to ask the germans + + + align:start position:0% +right so you've got to ask the germans +do they have a hard time right they + + align:start position:0% +do they have a hard time right they + + + align:start position:0% +do they have a hard time right they +don't + + align:start position:0% +don't + + + align:start position:0% +don't +all right so what some of them some of + + align:start position:0% +all right so what some of them some of + + + align:start position:0% +all right so what some of them some of +them blame it on the translations no + + align:start position:0% +them blame it on the translations no + + + align:start position:0% +them blame it on the translations no +it's not got it so what i'm going to try + + align:start position:0% +it's not got it so what i'm going to try + + + align:start position:0% +it's not got it so what i'm going to try +to do is to lay out + + align:start position:0% +to do is to lay out + + + align:start position:0% +to do is to lay out +these two + + align:start position:0% +these two + + + align:start position:0% +these two +approaches + + align:start position:0% +approaches + + + align:start position:0% +approaches +in a context + + align:start position:0% +in a context + + + align:start position:0% +in a context +so that you can see the meaning of it + + align:start position:0% +so that you can see the meaning of it + + + align:start position:0% +so that you can see the meaning of it +and i think once you get this context + + align:start position:0% +and i think once you get this context + + + align:start position:0% +and i think once you get this context +and the meaning of it the stuff + + align:start position:0% +and the meaning of it the stuff + + + align:start position:0% +and the meaning of it the stuff +falls out pretty clearly it falls out + + align:start position:0% +falls out pretty clearly it falls out + + + align:start position:0% +falls out pretty clearly it falls out +clearly to me + + align:start position:0% +clearly to me + + + align:start position:0% +clearly to me +and i've been successful in the argument + + align:start position:0% +and i've been successful in the argument + + + align:start position:0% +and i've been successful in the argument +arguing it + + align:start position:0% +arguing it + + + align:start position:0% +arguing it +let me try it with you okay + + align:start position:0% +let me try it with you okay + + + align:start position:0% +let me try it with you okay +so let's see if the context is going to + + align:start position:0% +so let's see if the context is going to + + + align:start position:0% +so let's see if the context is going to +work + + align:start position:0% + + + + align:start position:0% + +so with that i'll that's what i'll cover + + align:start position:0% +so with that i'll that's what i'll cover + + + align:start position:0% +so with that i'll that's what i'll cover +now any more questions or + + align:start position:0% +now any more questions or + + + align:start position:0% +now any more questions or +comments + + align:start position:0% +comments + + + align:start position:0% +comments +whenever i ask for questions i'm also + + align:start position:0% +whenever i ask for questions i'm also + + + align:start position:0% +whenever i ask for questions i'm also +leaving the possibilities of them for + + align:start position:0% +leaving the possibilities of them for + + + align:start position:0% +leaving the possibilities of them for +comments + + align:start position:0% +comments + + + align:start position:0% +comments +okay graduate class right + + align:start position:0% +okay graduate class right + + + align:start position:0% +okay graduate class right +comment + + align:start position:0% +comment + + + align:start position:0% +comment +undergraduates they don't have any + + align:start position:0% +undergraduates they don't have any + + + align:start position:0% +undergraduates they don't have any +authority + + align:start position:0% + + + + align:start position:0% + +say what do you say i remember the day + + align:start position:0% +say what do you say i remember the day + + + align:start position:0% +say what do you say i remember the day +huh + + align:start position:0% + + + + align:start position:0% + +i was told about this professor at + + align:start position:0% +i was told about this professor at + + + align:start position:0% +i was told about this professor at +oberlin + + align:start position:0% + + + + align:start position:0% + +who would uh + + align:start position:0% +who would uh + + + align:start position:0% +who would uh +cut a philosophy professor + + align:start position:0% +cut a philosophy professor + + + align:start position:0% +cut a philosophy professor +who would come into class + + align:start position:0% +who would come into class + + + align:start position:0% +who would come into class +and + + align:start position:0% +and + + + align:start position:0% +and +lie down on his desk + + align:start position:0% +lie down on his desk + + + align:start position:0% +lie down on his desk +and put his robe book on his chest + + align:start position:0% +and put his robe book on his chest + + + align:start position:0% +and put his robe book on his chest +and say now when somebody says something + + align:start position:0% +and say now when somebody says something + + + align:start position:0% +and say now when somebody says something +interesting + + align:start position:0% +interesting + + + align:start position:0% +interesting +i'll give you a grade + + align:start position:0% + + + + align:start position:0% + +nobody asked if he was really asleep + + align:start position:0% +nobody asked if he was really asleep + + + align:start position:0% +nobody asked if he was really asleep +back down there but the students would + + align:start position:0% +back down there but the students would + + + align:start position:0% +back down there but the students would +start to discover it was really + + align:start position:0% +start to discover it was really + + + align:start position:0% +start to discover it was really +intimidating + + align:start position:0% + + + + align:start position:0% + +oh + + align:start position:0% + + + + align:start position:0% + +i'm not going to do that because i might + + align:start position:0% +i'm not going to do that because i might + + + align:start position:0% +i'm not going to do that because i might +wind up going right to sleep + + align:start position:0% + + + + align:start position:0% + +but i guess the main point of what i + + align:start position:0% +but i guess the main point of what i + + + align:start position:0% +but i guess the main point of what i +just said is that i really do appreciate + + align:start position:0% +just said is that i really do appreciate + + + align:start position:0% +just said is that i really do appreciate +the + + align:start position:0% + + + + align:start position:0% + +imaginative pedagogy i really do + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +i think 325 on purpose for the because + + align:start position:0% +i think 325 on purpose for the because + + + align:start position:0% +i think 325 on purpose for the because +of the council yes + + align:start position:0% +of the council yes + + + align:start position:0% +of the council yes +yeah but i put circa if they said uh + + align:start position:0% +yeah but i put circa if they said uh + + + align:start position:0% +yeah but i put circa if they said uh +fourth century + + align:start position:0% +fourth century + + + align:start position:0% +fourth century +they put up a circle there but 325 + + align:start position:0% +they put up a circle there but 325 + + + align:start position:0% +they put up a circle there but 325 +because of the council + + align:start position:0% + + + + align:start position:0% + +uh let's see how we're doing can we + + align:start position:0% +uh let's see how we're doing can we + + + align:start position:0% +uh let's see how we're doing can we +tell me about these lights + + align:start position:0% + + + + align:start position:0% + +if can you see it better + + align:start position:0% + + + + align:start position:0% + +if you turn the front ones off + + align:start position:0% +if you turn the front ones off + + + align:start position:0% +if you turn the front ones off +yes + + align:start position:0% +yes + + + align:start position:0% +yes +better yes uh + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +roman empire + + align:start position:0% + + + + align:start position:0% + +roughly 325 a.d the color coding is in + + align:start position:0% +roughly 325 a.d the color coding is in + + + align:start position:0% +roughly 325 a.d the color coding is in +this particular uh + + align:start position:0% +this particular uh + + + align:start position:0% +this particular uh +picture + + align:start position:0% +picture + + + align:start position:0% +picture +is there just to show the differences of + + align:start position:0% +is there just to show the differences of + + + align:start position:0% +is there just to show the differences of +the provinces + + align:start position:0% + + + + align:start position:0% + +this being read and this being red and + + align:start position:0% +this being read and this being red and + + + align:start position:0% +this being read and this being red and +this being red has nothing to do + + align:start position:0% + + + + align:start position:0% + +uh + + align:start position:0% +uh + + + align:start position:0% +uh +and in 325 a d + + align:start position:0% +and in 325 a d + + + align:start position:0% +and in 325 a d +was when + + align:start position:0% +was when + + + align:start position:0% +was when +was right after constantine the great + + align:start position:0% + + + + align:start position:0% + +unified the empire + + align:start position:0% +unified the empire + + + align:start position:0% +unified the empire +and made christianity the state religion + + align:start position:0% +and made christianity the state religion + + + align:start position:0% +and made christianity the state religion +of the roman empire + + align:start position:0% + + + + align:start position:0% + +now unified the empire + + align:start position:0% +now unified the empire + + + align:start position:0% +now unified the empire +the empire is divided east and west + + align:start position:0% +the empire is divided east and west + + + align:start position:0% +the empire is divided east and west +in at least three ways geographically + + align:start position:0% +in at least three ways geographically + + + align:start position:0% +in at least three ways geographically +culturally + + align:start position:0% +culturally + + + align:start position:0% +culturally +and politically + + align:start position:0% + + + + align:start position:0% + +it is divided east and west + + align:start position:0% +it is divided east and west + + + align:start position:0% +it is divided east and west +geographically pretty much along + + align:start position:0% +geographically pretty much along + + + align:start position:0% +geographically pretty much along +this vertical line that you can just + + align:start position:0% +this vertical line that you can just + + + align:start position:0% +this vertical line that you can just +barely see here + + align:start position:0% +barely see here + + + align:start position:0% +barely see here +where you've got greece on one side + + align:start position:0% +where you've got greece on one side + + + align:start position:0% +where you've got greece on one side +uh and all of what we now call turkey + + align:start position:0% +uh and all of what we now call turkey + + + align:start position:0% +uh and all of what we now call turkey +and the middle east + + align:start position:0% +and the middle east + + + align:start position:0% +and the middle east +and some of + + align:start position:0% +and some of + + + align:start position:0% +and some of +egypt + + align:start position:0% +egypt + + + align:start position:0% +egypt +and the west is north africa + + align:start position:0% +and the west is north africa + + + align:start position:0% +and the west is north africa +and spain and + + align:start position:0% +and spain and + + + align:start position:0% +and spain and +france and england and italy + + align:start position:0% +france and england and italy + + + align:start position:0% +france and england and italy +and others + + align:start position:0% +and others + + + align:start position:0% +and others +okay + + align:start position:0% +okay + + + align:start position:0% +okay +culturally + + align:start position:0% +culturally + + + align:start position:0% +culturally +this is the most important part + + align:start position:0% + + + + align:start position:0% + +have you ever seen have you ever read + + align:start position:0% +have you ever seen have you ever read + + + align:start position:0% +have you ever seen have you ever read +the new york the new yorker magazine + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +do you like the covers + + align:start position:0% +do you like the covers + + + align:start position:0% +do you like the covers +the covers always have some kind of + + align:start position:0% +the covers always have some kind of + + + align:start position:0% +the covers always have some kind of +message + + align:start position:0% +message + + + align:start position:0% +message +ostensibly if you're a new yorker it + + align:start position:0% +ostensibly if you're a new yorker it + + + align:start position:0% +ostensibly if you're a new yorker it +picks up better you can understand it + + align:start position:0% +picks up better you can understand it + + + align:start position:0% +picks up better you can understand it +better than other people + + align:start position:0% +better than other people + + + align:start position:0% +better than other people +well there's a cover + + align:start position:0% +well there's a cover + + + align:start position:0% +well there's a cover +and it's done by steinberg i should have + + align:start position:0% +and it's done by steinberg i should have + + + align:start position:0% +and it's done by steinberg i should have +brought it in i have + + align:start position:0% +brought it in i have + + + align:start position:0% +brought it in i have +the big poster of it in my uh at my uh + + align:start position:0% +the big poster of it in my uh at my uh + + + align:start position:0% +the big poster of it in my uh at my uh +on my apartment i carry wherever i go + + align:start position:0% +on my apartment i carry wherever i go + + + align:start position:0% +on my apartment i carry wherever i go +now if i'm at a hotel but if i'm going + + align:start position:0% +now if i'm at a hotel but if i'm going + + + align:start position:0% +now if i'm at a hotel but if i'm going +to stay at some point + + align:start position:0% +to stay at some point + + + align:start position:0% +to stay at some point +i carry that and put it on the wall it's + + align:start position:0% +i carry that and put it on the wall it's + + + align:start position:0% +i carry that and put it on the wall it's +about this tall + + align:start position:0% +about this tall + + + align:start position:0% +about this tall +and i have uh + + align:start position:0% +and i have uh + + + align:start position:0% +and i have uh +it's numb he's numbered his uh posters i + + align:start position:0% +it's numb he's numbered his uh posters i + + + align:start position:0% +it's numb he's numbered his uh posters i +have something around 355. + + align:start position:0% +have something around 355. + + + align:start position:0% +have something around 355. +so + + align:start position:0% +so + + + align:start position:0% +so +it's an original + + align:start position:0% +it's an original + + + align:start position:0% +it's an original +and it's the 355th one + + align:start position:0% +and it's the 355th one + + + align:start position:0% +and it's the 355th one +that he did + + align:start position:0% +that he did + + + align:start position:0% +that he did +and what it does is it's just incredible + + align:start position:0% +and what it does is it's just incredible + + + align:start position:0% +and what it does is it's just incredible +uh it has a picture it's called i think + + align:start position:0% +uh it has a picture it's called i think + + + align:start position:0% +uh it has a picture it's called i think +it's called the new yorker's view of the + + align:start position:0% +it's called the new yorker's view of the + + + align:start position:0% +it's called the new yorker's view of the +world it has a picture of + + align:start position:0% +world it has a picture of + + + align:start position:0% +world it has a picture of +some buildings in new york city + + align:start position:0% + + + + align:start position:0% + +and then that's the foreground + + align:start position:0% +and then that's the foreground + + + align:start position:0% +and then that's the foreground +then then as you go up you go back + + align:start position:0% +then then as you go up you go back + + + align:start position:0% +then then as you go up you go back +so as you go up the next thing is the um + + align:start position:0% +so as you go up the next thing is the um + + + align:start position:0% +so as you go up the next thing is the um +hudson river + + align:start position:0% +hudson river + + + align:start position:0% +hudson river +and everything else is wilderness + + align:start position:0% +and everything else is wilderness + + + align:start position:0% +and everything else is wilderness +there's a little place over there they + + align:start position:0% +there's a little place over there they + + + align:start position:0% +there's a little place over there they +say chicago + + align:start position:0% +say chicago + + + align:start position:0% +say chicago +there's a little hill over there and + + align:start position:0% +there's a little hill over there and + + + align:start position:0% +there's a little hill over there and +they say los angeles + + align:start position:0% +they say los angeles + + + align:start position:0% +they say los angeles +there's a pond up here called the + + align:start position:0% +there's a pond up here called the + + + align:start position:0% +there's a pond up here called the +pacific ocean + + align:start position:0% +pacific ocean + + + align:start position:0% +pacific ocean +and then there's some land and there's a + + align:start position:0% +and then there's some land and there's a + + + align:start position:0% +and then there's some land and there's a +little word says japan and uss i mean + + align:start position:0% +little word says japan and uss i mean + + + align:start position:0% +little word says japan and uss i mean +the new york + + align:start position:0% +the new york + + + align:start position:0% +the new york +picture of the world is that everything + + align:start position:0% +picture of the world is that everything + + + align:start position:0% +picture of the world is that everything +that is civilization and that is + + align:start position:0% +that is civilization and that is + + + align:start position:0% +that is civilization and that is +happening is here when you walk across + + align:start position:0% +happening is here when you walk across + + + align:start position:0% +happening is here when you walk across +when you get out of + + align:start position:0% +when you get out of + + + align:start position:0% +when you get out of +one of those bridges + + align:start position:0% +one of those bridges + + + align:start position:0% +one of those bridges +then you're in the wasteland + + align:start position:0% +then you're in the wasteland + + + align:start position:0% +then you're in the wasteland +okay + + align:start position:0% +okay + + + align:start position:0% +okay +um + + align:start position:0% +um + + + align:start position:0% +um +the + + align:start position:0% +the + + + align:start position:0% +the +people who lived in the eastern part of + + align:start position:0% +people who lived in the eastern part of + + + align:start position:0% +people who lived in the eastern part of +the empire felt that way about the west + + align:start position:0% + + + + align:start position:0% + +this was this this was + + align:start position:0% +this was this this was + + + align:start position:0% +this was this this was +high culture over here + + align:start position:0% +high culture over here + + + align:start position:0% +high culture over here +this was on the wasteland over there + + align:start position:0% +this was on the wasteland over there + + + align:start position:0% +this was on the wasteland over there +even rome forget about what they say + + align:start position:0% +even rome forget about what they say + + + align:start position:0% +even rome forget about what they say +about hollywood + + align:start position:0% +about hollywood + + + align:start position:0% +about hollywood +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and the romans any one of them who had + + align:start position:0% +and the romans any one of them who had + + + align:start position:0% +and the romans any one of them who had +been out to the east + + align:start position:0% +been out to the east + + + align:start position:0% +been out to the east +felt pretty much the same way + + align:start position:0% + + + + align:start position:0% + +they didn't even speak the same language + + align:start position:0% + + + + align:start position:0% + +in the west the + + align:start position:0% +in the west the + + + align:start position:0% +in the west the +the language of choice mainly of the + + align:start position:0% +the language of choice mainly of the + + + align:start position:0% +the language of choice mainly of the +scholars and the uh upper classes + + align:start position:0% +scholars and the uh upper classes + + + align:start position:0% +scholars and the uh upper classes +uh but uh of anybody else who could + + align:start position:0% +uh but uh of anybody else who could + + + align:start position:0% +uh but uh of anybody else who could +speak uh latin was the language of the + + align:start position:0% +speak uh latin was the language of the + + + align:start position:0% +speak uh latin was the language of the +realm in the west + + align:start position:0% + + + + align:start position:0% + +what was the language of the realm in + + align:start position:0% +what was the language of the realm in + + + align:start position:0% +what was the language of the realm in +the east it was not that + + align:start position:0% + + + + align:start position:0% + +you want to guess + + align:start position:0% +you want to guess + + + align:start position:0% +you want to guess +persian + + align:start position:0% +persian + + + align:start position:0% +persian +that's a good guess + + align:start position:0% +that's a good guess + + + align:start position:0% +that's a good guess +she said persia + + align:start position:0% +she said persia + + + align:start position:0% +she said persia +would you say hebrew + + align:start position:0% +would you say hebrew + + + align:start position:0% +would you say hebrew +sure okay + + align:start position:0% +sure okay + + + align:start position:0% +sure okay +greek greek + + align:start position:0% + + + + align:start position:0% + +right it was greek that's why they call + + align:start position:0% +right it was greek that's why they call + + + align:start position:0% +right it was greek that's why they call +it the the hellenistic part + + align:start position:0% +it the the hellenistic part + + + align:start position:0% +it the the hellenistic part +of the empire + + align:start position:0% +of the empire + + + align:start position:0% +of the empire +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and + + align:start position:0% +and + + + align:start position:0% +and +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +in the west + + align:start position:0% + + + + align:start position:0% + +um + + align:start position:0% +um + + + align:start position:0% +um +the uh + + align:start position:0% + + + + align:start position:0% + +the the people out here were just like + + align:start position:0% +the the people out here were just like + + + align:start position:0% +the the people out here were just like +the romans + + align:start position:0% +the romans + + + align:start position:0% +the romans +that + + align:start position:0% +that + + + align:start position:0% +that +made the impact they were very + + align:start position:0% +made the impact they were very + + + align:start position:0% +made the impact they were very +uh concerned about + + align:start position:0% +uh concerned about + + + align:start position:0% +uh concerned about +militarism + + align:start position:0% +militarism + + + align:start position:0% +militarism +okay because at this time + + align:start position:0% +okay because at this time + + + align:start position:0% +okay because at this time +there was a great flood of + + align:start position:0% +there was a great flood of + + + align:start position:0% +there was a great flood of +several waves + + align:start position:0% +several waves + + + align:start position:0% +several waves +i don't want to use the word + + align:start position:0% +i don't want to use the word + + + align:start position:0% +i don't want to use the word +several waves of people coming in + + align:start position:0% +several waves of people coming in + + + align:start position:0% +several waves of people coming in +to this part of europe + + align:start position:0% +to this part of europe + + + align:start position:0% +to this part of europe +from + + align:start position:0% +from + + + align:start position:0% +from +asia + + align:start position:0% +asia + + + align:start position:0% +asia +the teutonic tribes + + align:start position:0% +the teutonic tribes + + + align:start position:0% +the teutonic tribes +now they came in in more than one way + + align:start position:0% +now they came in in more than one way + + + align:start position:0% +now they came in in more than one way +there was an earlier wave where they + + align:start position:0% +there was an earlier wave where they + + + align:start position:0% +there was an earlier wave where they +came in + + align:start position:0% +came in + + + align:start position:0% +came in +and occupied these northern parts + + align:start position:0% +and occupied these northern parts + + + align:start position:0% +and occupied these northern parts +vikings + + align:start position:0% +vikings + + + align:start position:0% +vikings +but the big waves came in around this + + align:start position:0% +but the big waves came in around this + + + align:start position:0% +but the big waves came in around this +round this time + + align:start position:0% +round this time + + + align:start position:0% +round this time +and we know why they came in + + align:start position:0% +and we know why they came in + + + align:start position:0% +and we know why they came in +it was a big drought out here + + align:start position:0% + + + + align:start position:0% + +now + + align:start position:0% +now + + + align:start position:0% +now +the historians and anthropologists that + + align:start position:0% +the historians and anthropologists that + + + align:start position:0% +the historians and anthropologists that +i read + + align:start position:0% +i read + + + align:start position:0% +i read +are + + align:start position:0% + + + + align:start position:0% + +when they say that they don't know why + + align:start position:0% +when they say that they don't know why + + + align:start position:0% +when they say that they don't know why +somebody migrated from one area to + + align:start position:0% +somebody migrated from one area to + + + align:start position:0% +somebody migrated from one area to +another + + align:start position:0% +another + + + align:start position:0% +another +it does not mean that they don't have + + align:start position:0% +it does not mean that they don't have + + + align:start position:0% +it does not mean that they don't have +some idea about why they do it + + align:start position:0% +some idea about why they do it + + + align:start position:0% +some idea about why they do it +it's usually some + + align:start position:0% +it's usually some + + + align:start position:0% +it's usually some +drought or disease + + align:start position:0% +drought or disease + + + align:start position:0% +drought or disease +or population expansion + + align:start position:0% +or population expansion + + + align:start position:0% +or population expansion +of some sort or persecution by somebody + + align:start position:0% +of some sort or persecution by somebody + + + align:start position:0% +of some sort or persecution by somebody +else further out + + align:start position:0% +else further out + + + align:start position:0% +else further out +okay + + align:start position:0% +okay + + + align:start position:0% +okay +all right but this time they pretty much + + align:start position:0% +all right but this time they pretty much + + + align:start position:0% +all right but this time they pretty much +know it was they had a series of bad + + align:start position:0% +know it was they had a series of bad + + + align:start position:0% +know it was they had a series of bad +droughts up in asia + + align:start position:0% +droughts up in asia + + + align:start position:0% +droughts up in asia +and great numbers of people came + + align:start position:0% +and great numbers of people came + + + align:start position:0% +and great numbers of people came +in here + + align:start position:0% +in here + + + align:start position:0% +in here +and they were all your your goths + + align:start position:0% +and they were all your your goths + + + align:start position:0% +and they were all your your goths +which include the ostrogoths and the + + align:start position:0% +which include the ostrogoths and the + + + align:start position:0% +which include the ostrogoths and the +visigoth + + align:start position:0% +visigoth + + + align:start position:0% +visigoth +the + + align:start position:0% +the + + + align:start position:0% +the +vandals + + align:start position:0% +vandals + + + align:start position:0% +vandals +uh + + align:start position:0% +uh + + + align:start position:0% +uh +all of these people came in from this + + align:start position:0% +all of these people came in from this + + + align:start position:0% +all of these people came in from this +area here and they terrified the empire + + align:start position:0% +area here and they terrified the empire + + + align:start position:0% +area here and they terrified the empire +because they had a fighting nature to + + align:start position:0% +because they had a fighting nature to + + + align:start position:0% +because they had a fighting nature to +them + + align:start position:0% +them + + + align:start position:0% +them +and they would raid over these borders + + align:start position:0% +and they would raid over these borders + + + align:start position:0% +and they would raid over these borders +okay and in 410 a.d alaric the goth + + align:start position:0% +okay and in 410 a.d alaric the goth + + + align:start position:0% +okay and in 410 a.d alaric the goth +sacked rome + + align:start position:0% + + + + align:start position:0% + +all right now + + align:start position:0% + + + + align:start position:0% + +here's the cultural point that i want to + + align:start position:0% +here's the cultural point that i want to + + + align:start position:0% +here's the cultural point that i want to +carry into the universities + + align:start position:0% +carry into the universities + + + align:start position:0% +carry into the universities +and it's going to be one of my major + + align:start position:0% +and it's going to be one of my major + + + align:start position:0% +and it's going to be one of my major +points + + align:start position:0% + + + + align:start position:0% + +uh in this lecture + + align:start position:0% +uh in this lecture + + + align:start position:0% +uh in this lecture +here it + + align:start position:0% +here it + + + align:start position:0% +here it +is okay ready + + align:start position:0% + + + + align:start position:0% + +in the period + + align:start position:0% + + + + align:start position:0% + +between 650 + + align:start position:0% +between 650 + + + align:start position:0% +between 650 +bc and 650 a.d all your major religions + + align:start position:0% +bc and 650 a.d all your major religions + + + align:start position:0% +bc and 650 a.d all your major religions +except two + + align:start position:0% +except two + + + align:start position:0% +except two +were found + + align:start position:0% +were found + + + align:start position:0% +were found +in these areas + + align:start position:0% + + + + align:start position:0% + +judaism was + + align:start position:0% +judaism was + + + align:start position:0% +judaism was +founded before all that + + align:start position:0% +founded before all that + + + align:start position:0% +founded before all that +and uh + + align:start position:0% +and uh + + + align:start position:0% +and uh +islam was founded + + align:start position:0% +islam was founded + + + align:start position:0% +islam was founded +after + + align:start position:0% +after + + + align:start position:0% +after +but everything else was + + align:start position:0% +but everything else was + + + align:start position:0% +but everything else was +coming around this time not just there + + align:start position:0% +coming around this time not just there + + + align:start position:0% +coming around this time not just there +but when you think of buddhism buddhism + + align:start position:0% +but when you think of buddhism buddhism + + + align:start position:0% +but when you think of buddhism buddhism +it was the whole world + + align:start position:0% +it was the whole world + + + align:start position:0% +it was the whole world +it was it was very broad + + align:start position:0% +it was it was very broad + + + align:start position:0% +it was it was very broad +it was a very magical period + + align:start position:0% + + + + align:start position:0% + +and + + align:start position:0% + + + + align:start position:0% + +when christianity was formed + + align:start position:0% + + + + align:start position:0% + +there was there were some issues + + align:start position:0% + + + + align:start position:0% + +and one of the issues was this + + align:start position:0% +and one of the issues was this + + + align:start position:0% +and one of the issues was this +all right this is going to be a + + align:start position:0% +all right this is going to be a + + + align:start position:0% +all right this is going to be a +theological point but i'm going to make + + align:start position:0% +theological point but i'm going to make + + + align:start position:0% +theological point but i'm going to make +it an educational point that's going to + + align:start position:0% +it an educational point that's going to + + + align:start position:0% +it an educational point that's going to +last us last you for the rest of your + + align:start position:0% +last us last you for the rest of your + + + align:start position:0% +last us last you for the rest of your +career + + align:start position:0% +career + + + align:start position:0% +career +the theological point is this + + align:start position:0% +the theological point is this + + + align:start position:0% +the theological point is this +the question + + align:start position:0% +the question + + + align:start position:0% +the question +which is most important or which comes + + align:start position:0% +which is most important or which comes + + + align:start position:0% +which is most important or which comes +first + + align:start position:0% +first + + + align:start position:0% +first +faith + + align:start position:0% +faith + + + align:start position:0% +faith +or works + + align:start position:0% + + + + align:start position:0% + +do you have it in your mind + + align:start position:0% +do you have it in your mind + + + align:start position:0% +do you have it in your mind +that you are a good person and that will + + align:start position:0% +that you are a good person and that will + + + align:start position:0% +that you are a good person and that will +cause you to do good things + + align:start position:0% + + + + align:start position:0% + +or you'd best do good things otherwise + + align:start position:0% +or you'd best do good things otherwise + + + align:start position:0% +or you'd best do good things otherwise +you won't get into the + + align:start position:0% +you won't get into the + + + align:start position:0% +you won't get into the +you won't get salvation + + align:start position:0% + + + + align:start position:0% + +now in the east + + align:start position:0% +now in the east + + + align:start position:0% +now in the east +when all of these religions were vying + + align:start position:0% +when all of these religions were vying + + + align:start position:0% +when all of these religions were vying +with one another + + align:start position:0% +with one another + + + align:start position:0% +with one another +and i say that that there were people uh + + align:start position:0% +and i say that that there were people uh + + + align:start position:0% +and i say that that there were people uh +long before this time who knew that + + align:start position:0% +long before this time who knew that + + + align:start position:0% +long before this time who knew that +paganism + + align:start position:0% +paganism + + + align:start position:0% +paganism +could not last the romans + + align:start position:0% +could not last the romans + + + align:start position:0% +could not last the romans +in peace time because paganism was a + + align:start position:0% +in peace time because paganism was a + + + align:start position:0% +in peace time because paganism was a +warrior religion + + align:start position:0% +warrior religion + + + align:start position:0% +warrior religion +and i think that many of these religions + + align:start position:0% +and i think that many of these religions + + + align:start position:0% +and i think that many of these religions +were vying with each other it to be the + + align:start position:0% +were vying with each other it to be the + + + align:start position:0% +were vying with each other it to be the +state religion of the roman empire they + + align:start position:0% +state religion of the roman empire they + + + align:start position:0% +state religion of the roman empire they +just didn't know when it was going to + + align:start position:0% +just didn't know when it was going to + + + align:start position:0% +just didn't know when it was going to +come + + align:start position:0% +come + + + align:start position:0% +come +now that's my take on it i emphasize the + + align:start position:0% +now that's my take on it i emphasize the + + + align:start position:0% +now that's my take on it i emphasize the +word m-y + + align:start position:0% +word m-y + + + align:start position:0% +word m-y +right + + align:start position:0% + + + + align:start position:0% + +but in the east + + align:start position:0% +but in the east + + + align:start position:0% +but in the east +the problem of getting people to accept + + align:start position:0% +the problem of getting people to accept + + + align:start position:0% +the problem of getting people to accept +your religion was a problem of reason + + align:start position:0% +your religion was a problem of reason + + + align:start position:0% +your religion was a problem of reason +you had to argue with them + + align:start position:0% +you had to argue with them + + + align:start position:0% +you had to argue with them +because all of them had studied all of + + align:start position:0% +because all of them had studied all of + + + align:start position:0% +because all of them had studied all of +your intellectuals + + align:start position:0% +your intellectuals + + + align:start position:0% +your intellectuals +had studied greek philosophy + + align:start position:0% + + + + align:start position:0% + +they knew all about + + align:start position:0% +they knew all about + + + align:start position:0% +they knew all about +plato and aristotle + + align:start position:0% +plato and aristotle + + + align:start position:0% +plato and aristotle +and all of these people and so you had + + align:start position:0% +and all of these people and so you had + + + align:start position:0% +and all of these people and so you had +to sit down and reason it out with + + align:start position:0% +to sit down and reason it out with + + + align:start position:0% +to sit down and reason it out with +you had to get their faith before you + + align:start position:0% +you had to get their faith before you + + + align:start position:0% +you had to get their faith before you +could get their works + + align:start position:0% + + + + align:start position:0% + +guess what in the west + + align:start position:0% + + + + align:start position:0% + +you had to get their works + + align:start position:0% +you had to get their works + + + align:start position:0% +you had to get their works +all right people they want to hear about + + align:start position:0% +all right people they want to hear about + + + align:start position:0% +all right people they want to hear about +all of this theorizing + + align:start position:0% +all of this theorizing + + + align:start position:0% +all of this theorizing +what do you want me to do + + align:start position:0% +what do you want me to do + + + align:start position:0% +what do you want me to do +so works came before + + align:start position:0% +so works came before + + + align:start position:0% +so works came before +faith in the west + + align:start position:0% +faith in the west + + + align:start position:0% +faith in the west +faith came before works in the east + + align:start position:0% + + + + align:start position:0% + +now what does that have to do with + + align:start position:0% +now what does that have to do with + + + align:start position:0% +now what does that have to do with +universities + + align:start position:0% +universities + + + align:start position:0% +universities +well as you saw from the film + + align:start position:0% +well as you saw from the film + + + align:start position:0% +well as you saw from the film +uh whatever had whatever theologians + + align:start position:0% +uh whatever had whatever theologians + + + align:start position:0% +uh whatever had whatever theologians +theologians were thinking about had + + align:start position:0% +theologians were thinking about had + + + align:start position:0% +theologians were thinking about had +something to do with the universities + + align:start position:0% +something to do with the universities + + + align:start position:0% +something to do with the universities +they were the professors + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +now + + align:start position:0% +now + + + align:start position:0% +now +this is around 1500 + + align:start position:0% +this is around 1500 + + + align:start position:0% +this is around 1500 +a.d + + align:start position:0% +a.d + + + align:start position:0% +a.d +and now i want you to put in your mind + + align:start position:0% +and now i want you to put in your mind + + + align:start position:0% +and now i want you to put in your mind +that film that i showed + + align:start position:0% +that film that i showed + + + align:start position:0% +that film that i showed +where julius ii + + align:start position:0% +where julius ii + + + align:start position:0% +where julius ii +is the warrior pope + + align:start position:0% +is the warrior pope + + + align:start position:0% +is the warrior pope +this is during his time + + align:start position:0% +this is during his time + + + align:start position:0% +this is during his time +actually circa 1500 is pretty much his + + align:start position:0% +actually circa 1500 is pretty much his + + + align:start position:0% +actually circa 1500 is pretty much his +time + + align:start position:0% +time + + + align:start position:0% +time +right this is a map of europe it's kind + + align:start position:0% +right this is a map of europe it's kind + + + align:start position:0% +right this is a map of europe it's kind +of hard to see but you don't need this + + align:start position:0% +of hard to see but you don't need this + + + align:start position:0% +of hard to see but you don't need this +i'll + + align:start position:0% +i'll + + + align:start position:0% +i'll +see for you + + align:start position:0% + + + + align:start position:0% + +um + + align:start position:0% +um + + + align:start position:0% +um +this is a map of the universities in + + align:start position:0% +this is a map of the universities in + + + align:start position:0% +this is a map of the universities in +europe at that time it was about 75 of + + align:start position:0% +europe at that time it was about 75 of + + + align:start position:0% +europe at that time it was about 75 of +them + + align:start position:0% + + + + align:start position:0% + +uh this part + + align:start position:0% +uh this part + + + align:start position:0% +uh this part +of the map including + + align:start position:0% +of the map including + + + align:start position:0% +of the map including +most of + + align:start position:0% +most of + + + align:start position:0% +most of +italy + + align:start position:0% +italy + + + align:start position:0% +italy +but certainly all of what we call + + align:start position:0% +but certainly all of what we call + + + align:start position:0% +but certainly all of what we call +germania was what is called the holy + + align:start position:0% +germania was what is called the holy + + + align:start position:0% +germania was what is called the holy +roman + + align:start position:0% +roman + + + align:start position:0% +roman +empire that was established after + + align:start position:0% +empire that was established after + + + align:start position:0% +empire that was established after +the roman empire had fallen + + align:start position:0% +the roman empire had fallen + + + align:start position:0% +the roman empire had fallen +after islam had come in + + align:start position:0% +after islam had come in + + + align:start position:0% +after islam had come in +and after islam had pretty much gone + + align:start position:0% +and after islam had pretty much gone + + + align:start position:0% +and after islam had pretty much gone +back + + align:start position:0% +back + + + align:start position:0% +back +charlemagne came to power in around 1800 + + align:start position:0% +charlemagne came to power in around 1800 + + + align:start position:0% +charlemagne came to power in around 1800 +and depending on who you talked to was + + align:start position:0% +and depending on who you talked to was + + + align:start position:0% +and depending on who you talked to was +either charlemagne or otto the first + + align:start position:0% +either charlemagne or otto the first + + + align:start position:0% +either charlemagne or otto the first +that began the holy roman empire if you + + align:start position:0% +that began the holy roman empire if you + + + align:start position:0% +that began the holy roman empire if you +talk to a frenchman guess what the + + align:start position:0% +talk to a frenchman guess what the + + + align:start position:0% +talk to a frenchman guess what the +frenchman will say + + align:start position:0% +frenchman will say + + + align:start position:0% +frenchman will say +if you talk to a german what will the + + align:start position:0% +if you talk to a german what will the + + + align:start position:0% +if you talk to a german what will the +germans say i told the person + + align:start position:0% + + + + align:start position:0% + +it's important for me to say + + align:start position:0% +it's important for me to say + + + align:start position:0% +it's important for me to say +that this is what the germans in the + + align:start position:0% +that this is what the germans in the + + + align:start position:0% +that this is what the germans in the +20th century called + + align:start position:0% +20th century called + + + align:start position:0% +20th century called +the first reich + + align:start position:0% + + + + align:start position:0% + +you had an emperor that was located up + + align:start position:0% +you had an emperor that was located up + + + align:start position:0% +you had an emperor that was located up +around in here + + align:start position:0% +around in here + + + align:start position:0% +around in here +and guess who the high priest of the + + align:start position:0% +and guess who the high priest of the + + + align:start position:0% +and guess who the high priest of the +empire was + + align:start position:0% +empire was + + + align:start position:0% +empire was +the pope + + align:start position:0% +the pope + + + align:start position:0% +the pope +and then you had everybody else so there + + align:start position:0% +and then you had everybody else so there + + + align:start position:0% +and then you had everybody else so there +is remember the three principles of + + align:start position:0% +is remember the three principles of + + + align:start position:0% +is remember the three principles of +social order + + align:start position:0% +social order + + + align:start position:0% 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make is + + + align:start position:0% +and well the point i want to make is +that when christianity + + align:start position:0% +that when christianity + + + align:start position:0% +that when christianity +was introduced + + align:start position:0% +was introduced + + + align:start position:0% +was introduced +uh + + align:start position:0% +uh + + + align:start position:0% +uh +to + + align:start position:0% +to + + + align:start position:0% +to +the goths + + align:start position:0% +the goths + + + align:start position:0% +the goths +and others in the + + align:start position:0% +and others in the + + + align:start position:0% +and others in the +germanic part of europe and eastern + + align:start position:0% +germanic part of europe and eastern + + + align:start position:0% +germanic part of europe and eastern +europe it never fully overtook people's + + align:start position:0% +europe it never fully overtook people's + + + align:start position:0% +europe it never fully overtook people's +thinking + + align:start position:0% +thinking + + + align:start position:0% +thinking +the middle part remained + + align:start position:0% + + + + align:start position:0% + +now there's something very significant + + align:start position:0% +now there's something very significant + + + align:start position:0% +now there's something very significant +about this middle part + + align:start position:0% + + + + align:start position:0% + +very significant + + align:start position:0% +very significant + + + align:start position:0% +very significant +very significant + + align:start position:0% + + + + align:start position:0% + +and that is that when you look at + + align:start position:0% +and that is that when you look at + + + align:start position:0% +and that is that when you look at +their village pagan religion and ask who + + align:start position:0% +their village pagan religion and ask who + + + align:start position:0% +their village pagan religion and ask who +which of the gods lives live in those + + align:start position:0% +which of the gods lives live in those + + + align:start position:0% +which of the gods lives live in those +parts of the world + + align:start position:0% +parts of the world + + + align:start position:0% +parts of the world +what you're going to find is + + align:start position:0% + + + + align:start position:0% + +that one + + align:start position:0% +that one + + + align:start position:0% +that one +m-a-n-i-g manic + + align:start position:0% +m-a-n-i-g manic + + + align:start position:0% +m-a-n-i-g manic +i don't know if it's pronounced manic or + + align:start position:0% +i don't know if it's pronounced manic or + + + align:start position:0% +i don't know if it's pronounced manic or +maddening + + align:start position:0% + + + + align:start position:0% + +but look at it + + align:start position:0% + + + + align:start position:0% + +the individual has will + + align:start position:0% + + + + align:start position:0% + +christianity + + align:start position:0% +christianity + + + align:start position:0% +christianity +at least during these times would + + align:start position:0% +at least during these times would + + + align:start position:0% +at least during these times would +attribute + + align:start position:0% +attribute + + + align:start position:0% +attribute +will to god god had will + + align:start position:0% +will to god god had will + + + align:start position:0% +will to god god had will +but here + + align:start position:0% +but here + + + align:start position:0% +but here +they are talking about + + align:start position:0% +they are talking about + + + align:start position:0% +they are talking about +every human being having a will and that + + align:start position:0% +every human being having a will and that + + + align:start position:0% +every human being having a will and that +will being a part of your body + + align:start position:0% +will being a part of your body + + + align:start position:0% +will being a part of your body +and it even goes further than that the + + align:start position:0% +and it even goes further than that the + + + align:start position:0% +and it even goes further than that the +will + + align:start position:0% +will + + + align:start position:0% +will +could overdo the orla + + align:start position:0% +could overdo the orla + + + align:start position:0% +could overdo the orla +which was + + align:start position:0% +which was + + + align:start position:0% +which was +the god of your destiny + + align:start position:0% +the god of your destiny + + + align:start position:0% +the god of your destiny +and that is + + align:start position:0% +and that is + + + align:start position:0% +and that is +you could say that i have destiny and i + + align:start position:0% +you could say that i have destiny and i + + + align:start position:0% +you could say that i have destiny and i +have faith out in front of me and there + + align:start position:0% +have faith out in front of me and there + + + align:start position:0% +have faith out in front of me and there +are these gods who + + align:start position:0% +are these gods who + + + align:start position:0% +are these gods who +say + + align:start position:0% +say + + + align:start position:0% +say +that this is where i am going in this + + align:start position:0% +that this is where i am going in this + + + align:start position:0% +that this is where i am going in this +life + + align:start position:0% +life + + + align:start position:0% +life +but guess how you could oh how a human + + align:start position:0% +but guess how you could oh how a human + + + align:start position:0% +but guess how you could oh how a human +being could overcome the gods + + align:start position:0% +being could overcome the gods + + + align:start position:0% +being could overcome the gods +with the will + + align:start position:0% +with the will + + + align:start position:0% +with the will +i will it not i will not go that way + + align:start position:0% +i will it not i will not go that way + + + align:start position:0% +i will it not i will not go that way +free will + + align:start position:0% +free will + + + align:start position:0% +free will +okay + + align:start position:0% +okay + + + align:start position:0% +okay +do you see it coming that's the basis of + + align:start position:0% +do you see it coming that's the basis of + + + align:start position:0% +do you see it coming that's the basis of +constant deontology he lived in this + + align:start position:0% +constant deontology he lived in this + + + align:start position:0% +constant deontology he lived in this +area + + align:start position:0% + + + + align:start position:0% + +that's the point i'm gonna make + + align:start position:0% +that's the point i'm gonna make + + + align:start position:0% +that's the point i'm gonna make +okay + + align:start position:0% +okay + + + align:start position:0% +okay +it was out of this thinking about the + + align:start position:0% +it was out of this thinking about the + + + align:start position:0% +it was out of this thinking about the +will + + align:start position:0% +will + + + align:start position:0% +will +that + + align:start position:0% +that + + + align:start position:0% +that +took on in the west + + align:start position:0% +took on in the west + + + align:start position:0% +took on in the west +the notion + + align:start position:0% +the notion + + + align:start position:0% +the notion +that faith is more important than works + + align:start position:0% +that faith is more important than works + + + align:start position:0% +that faith is more important than works +because + + align:start position:0% +because + + + align:start position:0% +because +faith is of the mind just like the will + + align:start position:0% +faith is of the mind just like the will + + + align:start position:0% +faith is of the mind just like the will +is + + align:start position:0% + + + + align:start position:0% + +and it was luther martin luther + + align:start position:0% +and it was luther martin luther + + + align:start position:0% +and it was luther martin luther +who + + align:start position:0% +who + + + align:start position:0% +who +started the + + align:start position:0% +started the + + + align:start position:0% +started the +reformation with his 95 theses the most + + align:start position:0% +reformation with his 95 theses the most + + + align:start position:0% +reformation with his 95 theses the most +important one being + + align:start position:0% +important one being + + + align:start position:0% +important one being +you this it's between you and god to + + align:start position:0% +you this it's between you and god to + + + align:start position:0% +you this it's between you and god to +decide whether or not you're good not + + align:start position:0% +decide whether or not you're good not + + + align:start position:0% +decide whether or not you're good not +the pope + + align:start position:0% +the pope + + + align:start position:0% +the pope +not the pope judging what you do + + align:start position:0% +not the pope judging what you do + + + align:start position:0% +not the pope judging what you do +and you and what you do mainly is + + align:start position:0% +and you and what you do mainly is + + + align:start position:0% +and you and what you do mainly is +paying those tithes okay + + align:start position:0% +paying those tithes okay + + + align:start position:0% +paying those tithes okay +at a time when there's a new middle + + align:start position:0% +at a time when there's a new middle + + + align:start position:0% +at a time when there's a new middle +class + + align:start position:0% +class + + + align:start position:0% +class +that wants to enjoy the money they're + + align:start position:0% +that wants to enjoy the money they're + + + align:start position:0% +that wants to enjoy the money they're +making they don't have a whole lot of + + align:start position:0% +making they don't have a whole lot of + + + align:start position:0% +making they don't have a whole lot of +money to be given over to the pope + + align:start position:0% +money to be given over to the pope + + + align:start position:0% +money to be given over to the pope +all right + + align:start position:0% +all right + + + align:start position:0% +all right +so martin lu martin luther + + align:start position:0% +so martin lu martin luther + + + align:start position:0% +so martin lu martin luther +was just acting out of + + align:start position:0% +was just acting out of + + + align:start position:0% +was just acting out of +what was ordinary and normal for people + + align:start position:0% +what was ordinary and normal for people + + + align:start position:0% +what was ordinary and normal for people +around him at the time + + align:start position:0% + + + + align:start position:0% + +so now i think that's the end of that + + align:start position:0% +so now i think that's the end of that + + + align:start position:0% +so now i think that's the end of that +show now i want to talk a little bit in + + align:start position:0% +show now i want to talk a little bit in + + + align:start position:0% +show now i want to talk a little bit in +depth about the two points of view + + align:start position:0% + + + + align:start position:0% + +and and i want to say how + + align:start position:0% + + + + align:start position:0% + +i want you to put those points of view + + align:start position:0% +i want you to put those points of view + + + align:start position:0% +i want you to put those points of view +into this homework assignment + + align:start position:0% +into this homework assignment + + + align:start position:0% +into this homework assignment +all right + + align:start position:0% + + + + align:start position:0% + +let's start with + + align:start position:0% +let's start with + + + align:start position:0% +let's start with +utilitarianism + + align:start position:0% + + + + align:start position:0% + +we've had a pedestrian discussion of + + align:start position:0% +we've had a pedestrian discussion of + + + align:start position:0% +we've had a pedestrian discussion of +utilitarianism + + align:start position:0% +utilitarianism + + + align:start position:0% +utilitarianism +now let's + + align:start position:0% +now let's + + + align:start position:0% +now let's +go a little deeper + + align:start position:0% + + + + align:start position:0% + +and before the class is all over we'll + + align:start position:0% +and before the class is all over we'll + + + align:start position:0% +and before the class is all over we'll +go one more step in depth + + align:start position:0% +go one more step in depth + + + align:start position:0% +go one more step in depth +and we'll take something back that we + + align:start position:0% +and we'll take something back that we + + + align:start position:0% +and we'll take something back that we +said before we'll shape it right + + align:start position:0% +said before we'll shape it right + + + align:start position:0% +said before we'll shape it right +but this is the next step + + align:start position:0% +but this is the next step + + + align:start position:0% +but this is the next step +you'll be 90 there + + align:start position:0% +you'll be 90 there + + + align:start position:0% +you'll be 90 there +the rest of it is just + + align:start position:0% +the rest of it is just + + + align:start position:0% +the rest of it is just +gonna be icing on the cake this will get + + align:start position:0% +gonna be icing on the cake this will get + + + align:start position:0% +gonna be icing on the cake this will get +you 90 there + + align:start position:0% +you 90 there + + + align:start position:0% +you 90 there +all right we're in + + align:start position:0% +all right we're in + + + align:start position:0% +all right we're in +a place in the world + + align:start position:0% + + + + align:start position:0% + +we're in england + + align:start position:0% + + + + align:start position:0% + +where they're teaching greek philosophy + + align:start position:0% + + + + align:start position:0% + +but + + align:start position:0% +but + + + align:start position:0% +but +they are still motivated + + align:start position:0% +they are still motivated + + + align:start position:0% +they are still motivated +by the notion that works are more + + align:start position:0% +by the notion that works are more + + + align:start position:0% +by the notion that works are more +important + + align:start position:0% +important + + + align:start position:0% +important +than faith + + align:start position:0% +than faith + + + align:start position:0% +than faith +so when they teach science + + align:start position:0% +so when they teach science + + + align:start position:0% +so when they teach science +what are they going to be interested in + + align:start position:0% +what are they going to be interested in + + + align:start position:0% +what are they going to be interested in +empirical science + + align:start position:0% + + + + align:start position:0% + +they're going to be + + align:start position:0% +they're going to be + + + align:start position:0% +they're going to be +interested in rational science and + + align:start position:0% +interested in rational science and + + + align:start position:0% +interested in rational science and +mathematics too + + align:start position:0% +mathematics too + + + align:start position:0% +mathematics too +okay let's not + + align:start position:0% +okay let's not + + + align:start position:0% +okay let's not +forget that one of the best + + align:start position:0% +forget that one of the best + + + align:start position:0% +forget that one of the best +mathematicians around + + align:start position:0% +mathematicians around + + + align:start position:0% +mathematicians around +uh in uh + + align:start position:0% +uh in uh + + + align:start position:0% +uh in uh +our olden days was a guy by the name of + + align:start position:0% +our olden days was a guy by the name of + + + align:start position:0% +our olden days was a guy by the name of +bishop george barkley + + align:start position:0% +bishop george barkley + + + align:start position:0% +bishop george barkley +okay so it doesn't apply to all of them + + align:start position:0% +okay so it doesn't apply to all of them + + + align:start position:0% +okay so it doesn't apply to all of them +but basically they're in an environment + + align:start position:0% +but basically they're in an environment + + + align:start position:0% +but basically they're in an environment +where + + align:start position:0% +where + + + align:start position:0% +where +works is still more important than faith + + align:start position:0% +works is still more important than faith + + + align:start position:0% +works is still more important than faith +so when they start talking about science + + align:start position:0% +so when they start talking about science + + + align:start position:0% +so when they start talking about science +they're going to talk about rational + + align:start position:0% +they're going to talk about rational + + + align:start position:0% +they're going to talk about rational +science a little bit + + align:start position:0% +science a little bit + + + align:start position:0% +science a little bit +the theory + + align:start position:0% +the theory + + + align:start position:0% +the theory +but they're mainly going to be + + align:start position:0% +but they're mainly going to be + + + align:start position:0% +but they're mainly going to be +interested in + + align:start position:0% +interested in + + + align:start position:0% +interested in +empirical science + + align:start position:0% + + + + align:start position:0% + +mainly interested in empirical signs + + align:start position:0% +mainly interested in empirical signs + + + align:start position:0% +mainly interested in empirical signs +when they get to ethics + + align:start position:0% + + + + align:start position:0% + +they're going to be mainly interested in + + align:start position:0% +they're going to be mainly interested in + + + align:start position:0% +they're going to be mainly interested in +and a + + align:start position:0% +and a + + + align:start position:0% +and a +in ethical arguments that have is + + align:start position:0% +in ethical arguments that have is + + + align:start position:0% +in ethical arguments that have is +its basis and root + + align:start position:0% +its basis and root + + + align:start position:0% +its basis and root +in facts + + align:start position:0% +in facts + + + align:start position:0% +in facts +not ideas + + align:start position:0% + + + + align:start position:0% + +now here let's characterize the times + + align:start position:0% +now here let's characterize the times + + + align:start position:0% +now here let's characterize the times +uh john stuart mill gives gets all the + + align:start position:0% +uh john stuart mill gives gets all the + + + align:start position:0% +uh john stuart mill gives gets all the +credit + + align:start position:0% +credit + + + align:start position:0% +credit +for utilitarianism a lot of utilitarians + + align:start position:0% +for utilitarianism a lot of utilitarians + + + align:start position:0% +for utilitarianism a lot of utilitarians +before him + + align:start position:0% +before him + + + align:start position:0% +before him +uh he gets the credit because he more or + + align:start position:0% +uh he gets the credit because he more or + + + align:start position:0% +uh he gets the credit because he more or +less perfected the uh the theory + + align:start position:0% +less perfected the uh the theory + + + align:start position:0% +less perfected the uh the theory +but the one that i want to talk about + + align:start position:0% +but the one that i want to talk about + + + align:start position:0% +but the one that i want to talk about +which is not one of the first but what + + align:start position:0% +which is not one of the first but what + + + align:start position:0% +which is not one of the first but what +really gives it + + align:start position:0% +really gives it + + + align:start position:0% +really gives it +its context is a man named jeremy + + align:start position:0% +its context is a man named jeremy + + + align:start position:0% +its context is a man named jeremy +bentham + + align:start position:0% +bentham + + + align:start position:0% +bentham +i'd like you to know that name + + align:start position:0% +i'd like you to know that name + + + align:start position:0% +i'd like you to know that name +uh + + align:start position:0% +uh + + + align:start position:0% +uh +and here's why he gives the context + + align:start position:0% +and here's why he gives the context + + + align:start position:0% +and here's why he gives the context +jeremy bentham + + align:start position:0% + + + + align:start position:0% + +uh did most of his writing + + align:start position:0% +uh did most of his writing + + + align:start position:0% +uh did most of his writing +uh + + align:start position:0% +uh + + + align:start position:0% +uh +around 1800 a little bit before a little + + align:start position:0% +around 1800 a little bit before a little + + + align:start position:0% +around 1800 a little bit before a little +bit after + + align:start position:0% +bit after + + + align:start position:0% +bit after +and let's talk about 1800 + + align:start position:0% +and let's talk about 1800 + + + align:start position:0% +and let's talk about 1800 +okay + + align:start position:0% + + + + align:start position:0% + +less than 30 years before + + align:start position:0% +less than 30 years before + + + align:start position:0% +less than 30 years before +1776 we have the american revolution + + align:start position:0% + + + + align:start position:0% + +1789 we've got the french revolution + + align:start position:0% + + + + align:start position:0% + +1803 the holy roman empire collapses + + align:start position:0% +1803 the holy roman empire collapses + + + align:start position:0% +1803 the holy roman empire collapses +you get the feeling there's a whole lot + + align:start position:0% +you get the feeling there's a whole lot + + + align:start position:0% +you get the feeling there's a whole lot +of revolution going on + + align:start position:0% +of revolution going on + + + align:start position:0% +of revolution going on +and the revolutionaries are coming up + + align:start position:0% +and the revolutionaries are coming up + + + align:start position:0% +and the revolutionaries are coming up +with new philosophies for their new + + align:start position:0% +with new philosophies for their new + + + align:start position:0% +with new philosophies for their new +government + + align:start position:0% +government + + + align:start position:0% +government +jeremy bentham was interested in new + + align:start position:0% +jeremy bentham was interested in new + + + align:start position:0% +jeremy bentham was interested in new +laws + + align:start position:0% +laws + + + align:start position:0% +laws +for the english people they did not have + + align:start position:0% +for the english people they did not have + + + align:start position:0% +for the english people they did not have +a revolution + + align:start position:0% +a revolution + + + align:start position:0% +a revolution +it should have been but + + align:start position:0% +it should have been but + + + align:start position:0% +it should have been but +would have done a lot of good would have + + align:start position:0% +would have done a lot of good would have + + + align:start position:0% +would have done a lot of good would have +done a lot of good + + align:start position:0% + + + + align:start position:0% + +but there was a guy by the name of uh i + + align:start position:0% +but there was a guy by the name of uh i + + + align:start position:0% +but there was a guy by the name of uh i +just learned about him it turns out + + align:start position:0% +just learned about him it turns out + + + align:start position:0% +just learned about him it turns out +my stepson's elementary school was named + + align:start position:0% +my stepson's elementary school was named + + + align:start position:0% +my stepson's elementary school was named +edmund burke school + + align:start position:0% +edmund burke school + + + align:start position:0% +edmund burke school +and edmund burke wrote a paper + + align:start position:0% +and edmund burke wrote a paper + + + align:start position:0% +and edmund burke wrote a paper +uh + + align:start position:0% +uh + + + align:start position:0% +uh +to the aristocrats in england + + align:start position:0% +to the aristocrats in england + + + align:start position:0% +to the aristocrats in england +saying don't worry we're not going to + + align:start position:0% +saying don't worry we're not going to + + + align:start position:0% +saying don't worry we're not going to +have a revolution over here + + align:start position:0% +have a revolution over here + + + align:start position:0% +have a revolution over here +turned out he was right but it turned + + align:start position:0% +turned out he was right but it turned + + + align:start position:0% +turned out he was right but it turned +out he was wrong in another way it just + + align:start position:0% +out he was wrong in another way it just + + + align:start position:0% +out he was wrong in another way it just +was not a founder things did change + + align:start position:0% +was not a founder things did change + + + align:start position:0% +was not a founder things did change +dramatically + + align:start position:0% +dramatically + + + align:start position:0% +dramatically +and they were called the reforms of the + + align:start position:0% +and they were called the reforms of the + + + align:start position:0% +and they were called the reforms of the +1830s jeremy bentham was one of the + + align:start position:0% +1830s jeremy bentham was one of the + + + align:start position:0% +1830s jeremy bentham was one of the +leaders jeremy bentham was interested + + align:start position:0% +leaders jeremy bentham was interested + + + align:start position:0% +leaders jeremy bentham was interested +well his his movement was primarily + + align:start position:0% +well his his movement was primarily + + + align:start position:0% +well his his movement was primarily +interested in new laws + + align:start position:0% +interested in new laws + + + align:start position:0% +interested in new laws +particularly laws favoring the upper + + align:start position:0% +particularly laws favoring the upper + + + align:start position:0% +particularly laws favoring the upper +middle class + + align:start position:0% +middle class + + + align:start position:0% +middle class +as opposed to the aristocrats + + align:start position:0% +as opposed to the aristocrats + + + align:start position:0% +as opposed to the aristocrats +jerry jeremy bentham's starting point + + align:start position:0% +jerry jeremy bentham's starting point + + + align:start position:0% +jerry jeremy bentham's starting point +was + + align:start position:0% + + + + align:start position:0% + +morality ethics + + align:start position:0% +morality ethics + + + align:start position:0% +morality ethics +that what he wanted to say was that when + + align:start position:0% +that what he wanted to say was that when + + + align:start position:0% +that what he wanted to say was that when +we build these new laws we want them + + align:start position:0% +we build these new laws we want them + + + align:start position:0% +we build these new laws we want them +grounded in ethics they have to be right + + align:start position:0% +grounded in ethics they have to be right + + + align:start position:0% +grounded in ethics they have to be right +right you get the context now + + align:start position:0% +right you get the context now + + + align:start position:0% +right you get the context now +right so what he wants to do is to come + + align:start position:0% +right so what he wants to do is to come + + + align:start position:0% +right so what he wants to do is to come +up with an ethical theory + + align:start position:0% +up with an ethical theory + + + align:start position:0% +up with an ethical theory +that is compelling upon the people + + align:start position:0% +that is compelling upon the people + + + align:start position:0% +that is compelling upon the people +around him + + align:start position:0% +around him + + + align:start position:0% +around him +what would that ethical theory have to + + align:start position:0% +what would that ethical theory have to + + + align:start position:0% +what would that ethical theory have to +do + + align:start position:0% +do + + + align:start position:0% +do +be grounded on facts + + align:start position:0% +be grounded on facts + + + align:start position:0% +be grounded on facts +not on ideas + + align:start position:0% +not on ideas + + + align:start position:0% +not on ideas +and here's the way the utilitarians did + + align:start position:0% +and here's the way the utilitarians did + + + align:start position:0% +and here's the way the utilitarians did +it + + align:start position:0% +it + + + align:start position:0% +it +all right + + align:start position:0% + + + + align:start position:0% + +they got their clipboards + + align:start position:0% +they got their clipboards + + + align:start position:0% +they got their clipboards +and their pencils + + align:start position:0% +and their pencils + + + align:start position:0% +and their pencils +and they went out + + align:start position:0% +and they went out + + + align:start position:0% +and they went out +into + + align:start position:0% +into + + + align:start position:0% +into +the world and ask people questions + + align:start position:0% + + + + align:start position:0% + +they did not sit down under a tree + + align:start position:0% +they did not sit down under a tree + + + align:start position:0% +they did not sit down under a tree +with a loaf of bread + + align:start position:0% +with a loaf of bread + + + align:start position:0% +with a loaf of bread +and a bottle of wine and think through a + + align:start position:0% +and a bottle of wine and think through a + + + align:start position:0% +and a bottle of wine and think through a +great idea + + align:start position:0% +great idea + + + align:start position:0% +great idea +they went out and here's what they did + + align:start position:0% +they went out and here's what they did + + + align:start position:0% +they went out and here's what they did +they just asked themselves they used a + + align:start position:0% +they just asked themselves they used a + + + align:start position:0% +they just asked themselves they used a +method by plato + + align:start position:0% +method by plato + + + align:start position:0% +method by plato +they asked themselves + + align:start position:0% +they asked themselves + + + align:start position:0% +they asked themselves +they ask people + + align:start position:0% +they ask people + + + align:start position:0% +they ask people +you know + + align:start position:0% +you know + + + align:start position:0% +you know +why do you do why did you choose to do x + + align:start position:0% +why do you do why did you choose to do x + + + align:start position:0% +why do you do why did you choose to do x +instead of y + + align:start position:0% + + + + align:start position:0% + +okay they might ask you a question like + + align:start position:0% +okay they might ask you a question like + + + align:start position:0% +okay they might ask you a question like +why are you uh in graduate school + + align:start position:0% + + + + align:start position:0% + +make up an answer don't give me the + + align:start position:0% +make up an answer don't give me the + + + align:start position:0% +make up an answer don't give me the +truth you'll just make up an answer a + + align:start position:0% +truth you'll just make up an answer a + + + align:start position:0% +truth you'll just make up an answer a +reason why i'm in graduate school + + align:start position:0% +reason why i'm in graduate school + + + align:start position:0% +reason why i'm in graduate school +because + + align:start position:0% +because + + + align:start position:0% +because +i want to make more money when i get out + + align:start position:0% +i want to make more money when i get out + + + align:start position:0% +i want to make more money when i get out +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and they did something then they did + + align:start position:0% +and they did something then they did + + + align:start position:0% +and they did something then they did +something it sounds like actually i + + align:start position:0% +something it sounds like actually i + + + align:start position:0% +something it sounds like actually i +understand that plato got his method of + + align:start position:0% +understand that plato got his method of + + + align:start position:0% +understand that plato got his method of +ends and means from watching + + align:start position:0% +ends and means from watching + + + align:start position:0% +ends and means from watching +mothers uh quiz children + + align:start position:0% +mothers uh quiz children + + + align:start position:0% +mothers uh quiz children +i know as watching children quiz their + + align:start position:0% +i know as watching children quiz their + + + align:start position:0% +i know as watching children quiz their +mothers + + align:start position:0% +mothers + + + align:start position:0% +mothers +because a child at the right age i think + + align:start position:0% +because a child at the right age i think + + + align:start position:0% +because a child at the right age i think +it's about three + + align:start position:0% +it's about three + + + align:start position:0% +it's about three +when you tell them to do something + + align:start position:0% +when you tell them to do something + + + align:start position:0% +when you tell them to do something +they'll say why + + align:start position:0% +they'll say why + + + align:start position:0% +they'll say why +then when you tell them why guess what + + align:start position:0% +then when you tell them why guess what + + + align:start position:0% +then when you tell them why guess what +they'll say why + + align:start position:0% +they'll say why + + + align:start position:0% +they'll say why +okay + + align:start position:0% +okay + + + align:start position:0% +okay +because + + align:start position:0% +because + + + align:start position:0% +because +and what what plato would do is it ask + + align:start position:0% +and what what plato would do is it ask + + + align:start position:0% +and what what plato would do is it ask +you something and then you say then you + + align:start position:0% +you something and then you say then you + + + align:start position:0% +you something and then you say then you +give an answer then they say why didn't + + align:start position:0% +give an answer then they say why didn't + + + align:start position:0% +give an answer then they say why didn't +you give another answer + + align:start position:0% +you give another answer + + + align:start position:0% +you give another answer +and he would keep asking why until you + + align:start position:0% +and he would keep asking why until you + + + align:start position:0% +and he would keep asking why until you +stop giving + + align:start position:0% +stop giving + + + align:start position:0% +stop giving +new answers + + align:start position:0% +new answers + + + align:start position:0% +new answers +that last answer is what they called an + + align:start position:0% +that last answer is what they called an + + + align:start position:0% +that last answer is what they called an +end the rest of it was means to ends + + align:start position:0% +end the rest of it was means to ends + + + align:start position:0% +end the rest of it was means to ends +it's a theory called teleology + + align:start position:0% +it's a theory called teleology + + + align:start position:0% +it's a theory called teleology +i'd like for you to know this word + + align:start position:0% +i'd like for you to know this word + + + align:start position:0% +i'd like for you to know this word +i'd like for you to use + + align:start position:0% + + + + align:start position:0% + +this word + + align:start position:0% + + + + align:start position:0% + +in your homework assignment + + align:start position:0% +in your homework assignment + + + align:start position:0% +in your homework assignment +study of ends and means + + align:start position:0% +study of ends and means + + + align:start position:0% +study of ends and means +so what they what they came back from + + align:start position:0% +so what they what they came back from + + + align:start position:0% +so what they what they came back from +the field with was two things number one + + align:start position:0% +the field with was two things number one + + + align:start position:0% +the field with was two things number one +was + + align:start position:0% +was + + + align:start position:0% +was +that the it now listen to me carefully + + align:start position:0% +that the it now listen to me carefully + + + align:start position:0% +that the it now listen to me carefully +because + + align:start position:0% +because + + + align:start position:0% +because +you're to get this kind of language when + + align:start position:0% +you're to get this kind of language when + + + align:start position:0% +you're to get this kind of language when +you read philosophies + + align:start position:0% +you read philosophies + + + align:start position:0% +you read philosophies +the end of life + + align:start position:0% +the end of life + + + align:start position:0% +the end of life +is happiness not the end meaning death + + align:start position:0% +is happiness not the end meaning death + + + align:start position:0% +is happiness not the end meaning death +but the end + + align:start position:0% +but the end + + + align:start position:0% +but the end +meaning + + align:start position:0% +meaning + + + align:start position:0% +meaning +in relationship to means okay when you + + align:start position:0% +in relationship to means okay when you + + + align:start position:0% +in relationship to means okay when you +ask people why are they living + + align:start position:0% +ask people why are they living + + + align:start position:0% +ask people why are they living +and what are they how do they make their + + align:start position:0% +and what are they how do they make their + + + align:start position:0% +and what are they how do they make their +decisions + + align:start position:0% +decisions + + + align:start position:0% +decisions +they came up with in the end + + align:start position:0% +they came up with in the end + + + align:start position:0% +they came up with in the end +when you got down to the end when + + align:start position:0% +when you got down to the end when + + + align:start position:0% +when you got down to the end when +they've asked you why and you after a + + align:start position:0% +they've asked you why and you after a + + + align:start position:0% +they've asked you why and you after a +while you just keep saying the same + + align:start position:0% +while you just keep saying the same + + + align:start position:0% +while you just keep saying the same +thing over and over again in the end + + align:start position:0% +thing over and over again in the end + + + align:start position:0% +thing over and over again in the end +they said it was pleasure as opposed to + + align:start position:0% +they said it was pleasure as opposed to + + + align:start position:0% +they said it was pleasure as opposed to +pain + + align:start position:0% +pain + + + align:start position:0% +pain +it was happiness + + align:start position:0% +it was happiness + + + align:start position:0% +it was happiness +as opposed to unhappiness + + align:start position:0% +as opposed to unhappiness + + + align:start position:0% +as opposed to unhappiness +well down to that + + align:start position:0% +well down to that + + + align:start position:0% +well down to that +okay + + align:start position:0% +okay + + + align:start position:0% +okay +then they ask them + + align:start position:0% +then they ask them + + + align:start position:0% +then they ask them +well what are the kinds of things out + + align:start position:0% +well what are the kinds of things out + + + align:start position:0% +well what are the kinds of things out +here + + align:start position:0% +here + + + align:start position:0% +here +in the world that you think are good + + align:start position:0% +in the world that you think are good + + + align:start position:0% +in the world that you think are good +and which are things that you think are + + align:start position:0% +and which are things that you think are + + + align:start position:0% +and which are things that you think are +bad + + align:start position:0% +bad + + + align:start position:0% +bad +which are the things that you think are + + align:start position:0% +which are the things that you think are + + + align:start position:0% +which are the things that you think are +moral which are the things that you + + align:start position:0% +moral which are the things that you + + + align:start position:0% +moral which are the things that you +think are + + align:start position:0% +think are + + + align:start position:0% +think are +immoral they just ask people + + align:start position:0% +immoral they just ask people + + + align:start position:0% +immoral they just ask people +and there was a collection of things + + align:start position:0% +and there was a collection of things + + + align:start position:0% +and there was a collection of things +that most people sort of sort of agreed + + align:start position:0% +that most people sort of sort of agreed + + + align:start position:0% +that most people sort of sort of agreed +on + + align:start position:0% +on + + + align:start position:0% +on +uh it's wrong to murder somebody just + + align:start position:0% +uh it's wrong to murder somebody just + + + align:start position:0% +uh it's wrong to murder somebody just +because i feel okay things like that + + align:start position:0% +because i feel okay things like that + + + align:start position:0% +because i feel okay things like that +then they came back and they said + + align:start position:0% +then they came back and they said + + + align:start position:0% +then they came back and they said +which of + + align:start position:0% +which of + + + align:start position:0% +which of +uh how can i organize my life in terms + + align:start position:0% +uh how can i organize my life in terms + + + align:start position:0% +uh how can i organize my life in terms +of ends + + align:start position:0% + + + + align:start position:0% + +that respect those morals + + align:start position:0% + + + + align:start position:0% + +and the answer was + + align:start position:0% +and the answer was + + + align:start position:0% +and the answer was +act + + align:start position:0% +act + + + align:start position:0% +act +in such a way that i not only + + align:start position:0% +in such a way that i not only + + + align:start position:0% +in such a way that i not only +try to maximize my own happiness + + align:start position:0% +try to maximize my own happiness + + + align:start position:0% +try to maximize my own happiness +but maximize the happiness among all the + + align:start position:0% +but maximize the happiness among all the + + + align:start position:0% +but maximize the happiness among all the +affected parties + + align:start position:0% + + + + align:start position:0% + +of my actions all the parties affected + + align:start position:0% +of my actions all the parties affected + + + align:start position:0% +of my actions all the parties affected +by my action + + align:start position:0% +by my action + + + align:start position:0% +by my action +okay let's pause for a second let's try + + align:start position:0% +okay let's pause for a second let's try + + + align:start position:0% +okay let's pause for a second let's try +to interrogate this idea i mean sorry i + + align:start position:0% +to interrogate this idea i mean sorry i + + + align:start position:0% +to interrogate this idea i mean sorry i +don't i'm sorry i didn't want to say + + align:start position:0% +don't i'm sorry i didn't want to say + + + align:start position:0% +don't i'm sorry i didn't want to say +idea + + align:start position:0% +idea + + + align:start position:0% +idea +it is an idea but let's + + align:start position:0% +it is an idea but let's + + + align:start position:0% +it is an idea but let's +let's interrogate utilitarian + + align:start position:0% +let's interrogate utilitarian + + + align:start position:0% +let's interrogate utilitarian +utilitarianism a little bit + + align:start position:0% +utilitarianism a little bit + + + align:start position:0% +utilitarianism a little bit +let's interrogate all that + + align:start position:0% +let's interrogate all that + + + align:start position:0% +let's interrogate all that +i'll play the game but i want you to get + + align:start position:0% +i'll play the game but i want you to get + + + align:start position:0% +i'll play the game but i want you to get +into it at your own leisure and i want + + align:start position:0% +into it at your own leisure and i want + + + align:start position:0% +into it at your own leisure and i want +you all to be a little bit more + + align:start position:0% +you all to be a little bit more + + + align:start position:0% +you all to be a little bit more +aggressive + + align:start position:0% +aggressive + + + align:start position:0% +aggressive +about getting into these conversations + + align:start position:0% +about getting into these conversations + + + align:start position:0% +about getting into these conversations +okay + + align:start position:0% +okay + + + align:start position:0% +okay +not necessarily the day but as you go to + + align:start position:0% +not necessarily the day but as you go to + + + align:start position:0% +not necessarily the day but as you go to +particularly taking credit okay + + align:start position:0% +particularly taking credit okay + + + align:start position:0% +particularly taking credit okay +and this is where you really want to + + align:start position:0% +and this is where you really want to + + + align:start position:0% +and this is where you really want to +interrogate this thing okay + + align:start position:0% + + + + align:start position:0% + +i want to start out with what i think is + + align:start position:0% +i want to start out with what i think is + + + align:start position:0% +i want to start out with what i think is +the hard question the hardest question + + align:start position:0% +the hard question the hardest question + + + align:start position:0% +the hard question the hardest question +why should i + + align:start position:0% + + + + align:start position:0% + +maximize your happiness + + align:start position:0% + + + + align:start position:0% + +now there are two ways to answer that + + align:start position:0% +now there are two ways to answer that + + + align:start position:0% +now there are two ways to answer that +question what you think is a good answer + + align:start position:0% +question what you think is a good answer + + + align:start position:0% +question what you think is a good answer +to the question + + align:start position:0% +to the question + + + align:start position:0% +to the question +or what you think that + + align:start position:0% +or what you think that + + + align:start position:0% +or what you think that +a utilitarian would say + + align:start position:0% + + + + align:start position:0% + +i'm really interested in last one + + align:start position:0% +i'm really interested in last one + + + align:start position:0% +i'm really interested in last one +you understood yeah i'm not i'm not + + align:start position:0% +you understood yeah i'm not i'm not + + + align:start position:0% +you understood yeah i'm not i'm not +that's not a that's not a uh + + align:start position:0% +that's not a that's not a uh + + + align:start position:0% +that's not a that's not a uh +historical question + + align:start position:0% +historical question + + + align:start position:0% +historical question +why should i care about your health why + + align:start position:0% +why should i care about your health why + + + align:start position:0% +why should i care about your health why +should i maximize the happiness of all + + align:start position:0% +should i maximize the happiness of all + + + align:start position:0% +should i maximize the happiness of all +the affected parties so the utilitarian + + align:start position:0% +the affected parties so the utilitarian + + + align:start position:0% +the affected parties so the utilitarian +would say + + align:start position:0% +would say + + + align:start position:0% +would say +i think + + align:start position:0% + + + + align:start position:0% + +i should maximize other people's + + align:start position:0% +i should maximize other people's + + + align:start position:0% +i should maximize other people's +happiness because later on they will + + align:start position:0% +happiness because later on they will + + + align:start position:0% +happiness because later on they will +take action that affects me and if in + + align:start position:0% +take action that affects me and if in + + + align:start position:0% +take action that affects me and if in +the past i have made them happy then + + align:start position:0% +the past i have made them happy then + + + align:start position:0% +the past i have made them happy then +they will take action to make me that's + + align:start position:0% +they will take action to make me that's + + + align:start position:0% +they will take action to make me that's +a good utilitarian answer + + align:start position:0% + + + + align:start position:0% + +well then my my then i would say well + + align:start position:0% + + + + align:start position:0% + +all right + + align:start position:0% +all right + + + align:start position:0% +all right +is that really the first principle + + align:start position:0% +is that really the first principle + + + align:start position:0% +is that really the first principle +is it really the first principle + + align:start position:0% +is it really the first principle + + + align:start position:0% +is it really the first principle +maximizing the happiness of all affected + + align:start position:0% +maximizing the happiness of all affected + + + align:start position:0% +maximizing the happiness of all affected +persons when actually what you just said + + align:start position:0% +persons when actually what you just said + + + align:start position:0% +persons when actually what you just said +was the end is your own personal + + align:start position:0% +was the end is your own personal + + + align:start position:0% +was the end is your own personal +happiness + + align:start position:0% +happiness + + + align:start position:0% +happiness +why not say maximize my own personal + + align:start position:0% +why not say maximize my own personal + + + align:start position:0% +why not say maximize my own personal +happiness and then reason it out + + align:start position:0% +happiness and then reason it out + + + align:start position:0% +happiness and then reason it out +that in a society i cannot maximize my + + align:start position:0% +that in a society i cannot maximize my + + + align:start position:0% +that in a society i cannot maximize my +own personal happiness without trying to + + align:start position:0% +own personal happiness without trying to + + + align:start position:0% +own personal happiness without trying to +help maximize other people's happiness + + align:start position:0% +help maximize other people's happiness + + + align:start position:0% +help maximize other people's happiness +too that's not the end + + align:start position:0% +too that's not the end + + + align:start position:0% +too that's not the end +the end + + align:start position:0% +the end + + + align:start position:0% +the end +is your personal happiness + + align:start position:0% + + + + align:start position:0% + +okay well then let's be bold maybe the + + align:start position:0% +okay well then let's be bold maybe the + + + align:start position:0% +okay well then let's be bold maybe the +utilitarians got it wrong hold on a + + align:start position:0% +utilitarians got it wrong hold on a + + + align:start position:0% +utilitarians got it wrong hold on a +minute + + align:start position:0% +minute + + + align:start position:0% +minute +i'll pass this around + + align:start position:0% + + + + align:start position:0% + +all they do in this book is tear up + + align:start position:0% +all they do in this book is tear up + + + align:start position:0% +all they do in this book is tear up +utilitarians + + align:start position:0% + + + + align:start position:0% + +okay so uh let's tear it up answer my + + align:start position:0% +okay so uh let's tear it up answer my + + + align:start position:0% +okay so uh let's tear it up answer my +question + + align:start position:0% +question + + + align:start position:0% +question +maximizing the happiness of all the + + align:start position:0% +maximizing the happiness of all the + + + align:start position:0% +maximizing the happiness of all the +affected parties according to what you + + align:start position:0% +affected parties according to what you + + + align:start position:0% +affected parties according to what you +just said is not the end + + align:start position:0% +just said is not the end + + + align:start position:0% +just said is not the end +maximizing my own in other words there + + align:start position:0% +maximizing my own in other words there + + + align:start position:0% +maximizing my own in other words there +is a branch and a philosophy of ethics + + align:start position:0% +is a branch and a philosophy of ethics + + + align:start position:0% +is a branch and a philosophy of ethics +called hedonism + + align:start position:0% + + + + align:start position:0% + +bentham was a hedonist + + align:start position:0% + + + + align:start position:0% + +can we escape hedonism + + align:start position:0% +can we escape hedonism + + + align:start position:0% +can we escape hedonism +in + + align:start position:0% + + + + align:start position:0% + +sense to other utilitarianism and you + + align:start position:0% +sense to other utilitarianism and you + + + align:start position:0% +sense to other utilitarianism and you +can't just maximize your own happiness + + align:start position:0% +can't just maximize your own happiness + + + align:start position:0% +can't just maximize your own happiness +without worrying about others + + align:start position:0% +without worrying about others + + + align:start position:0% +without worrying about others +i agree but my problem is + + align:start position:0% + + + + align:start position:0% + +my problem is + + align:start position:0% +my problem is + + + align:start position:0% +my problem is +that + + align:start position:0% + + + + align:start position:0% + +the end of hedonism + + align:start position:0% +the end of hedonism + + + align:start position:0% +the end of hedonism +is not this maximization of everybody's + + align:start position:0% +is not this maximization of everybody's + + + align:start position:0% +is not this maximization of everybody's +happiness the end of + + align:start position:0% +happiness the end of + + + align:start position:0% +happiness the end of +hedonism is maximization of my happiness + + align:start position:0% +hedonism is maximization of my happiness + + + align:start position:0% +hedonism is maximization of my happiness +even though + + align:start position:0% +even though + + + align:start position:0% +even though +maximizing your happiness is a means + + align:start position:0% +maximizing your happiness is a means + + + align:start position:0% +maximizing your happiness is a means +to maximizing my happiness so why don't + + align:start position:0% +to maximizing my happiness so why don't + + + align:start position:0% +to maximizing my happiness so why don't +we just + + align:start position:0% +we just + + + align:start position:0% +we just +call a state of spain + + align:start position:0% +call a state of spain + + + align:start position:0% +call a state of spain +that + + align:start position:0% +that + + + align:start position:0% +that +he we don't want to be utilitarians we + + align:start position:0% +he we don't want to be utilitarians we + + + align:start position:0% +he we don't want to be utilitarians we +want to be hedonists + + align:start position:0% +want to be hedonists + + + align:start position:0% +want to be hedonists +and we want to maximize our own + + align:start position:0% +and we want to maximize our own + + + align:start position:0% +and we want to maximize our own +individual at the end of hedonism is to + + align:start position:0% +individual at the end of hedonism is to + + + align:start position:0% +individual at the end of hedonism is to +maximize our own individual + + align:start position:0% +maximize our own individual + + + align:start position:0% +maximize our own individual +pleasure or happiness and the smart + + align:start position:0% +pleasure or happiness and the smart + + + align:start position:0% +pleasure or happiness and the smart +thing to do is to help maximize others + + align:start position:0% +thing to do is to help maximize others + + + align:start position:0% +thing to do is to help maximize others +if we can do it why not just say that + + align:start position:0% +if we can do it why not just say that + + + align:start position:0% +if we can do it why not just say that +why don't we just come back and tell the + + align:start position:0% +why don't we just come back and tell the + + + align:start position:0% +why don't we just come back and tell the +lie we want to maximize everybody's + + align:start position:0% +lie we want to maximize everybody's + + + align:start position:0% +lie we want to maximize everybody's +happiness + + align:start position:0% +happiness + + + align:start position:0% +happiness +i've been in a + + align:start position:0% +i've been in a + + + align:start position:0% +i've been in a +devil's advocate + + align:start position:0% +devil's advocate + + + align:start position:0% +devil's advocate +maybe they got it wrong what if we place + + align:start position:0% +maybe they got it wrong what if we place + + + align:start position:0% +maybe they got it wrong what if we place +equal value + + align:start position:0% +equal value + + + align:start position:0% +equal value +on social order + + align:start position:0% +on social order + + + align:start position:0% +on social order +value on our own happiness and social + + align:start position:0% +value on our own happiness and social + + + align:start position:0% +value on our own happiness and social +order + + align:start position:0% +order + + + align:start position:0% +order +and so then + + align:start position:0% +and so then + + + align:start position:0% +and so then +you need + + align:start position:0% +you need + + + align:start position:0% +you need +everyone's happiness to be happening + + align:start position:0% +everyone's happiness to be happening + + + align:start position:0% +everyone's happiness to be happening +in order + + align:start position:0% + + + + align:start position:0% + +remember + + align:start position:0% +remember + + + align:start position:0% +remember +somebody saying something like that i + + align:start position:0% +somebody saying something like that i + + + align:start position:0% +somebody saying something like that i +can't remember who it was + + align:start position:0% +can't remember who it was + + + align:start position:0% +can't remember who it was +uh + + align:start position:0% +uh + + + align:start position:0% +uh +but if you said that + + align:start position:0% +but if you said that + + + align:start position:0% +but if you said that +the question would not be the question + + align:start position:0% +the question would not be the question + + + align:start position:0% +the question would not be the question +of reason the question would be compel + + align:start position:0% +of reason the question would be compel + + + align:start position:0% +of reason the question would be compel +compulsion + + align:start position:0% +compulsion + + + align:start position:0% +compulsion +how many people gonna buy that + + align:start position:0% + + + + align:start position:0% + +you gotta give me an end i'm not gonna + + align:start position:0% +you gotta give me an end i'm not gonna + + + align:start position:0% +you gotta give me an end i'm not gonna +believe you got two independent + + align:start position:0% +believe you got two independent + + + align:start position:0% +believe you got two independent +equally valuable + + align:start position:0% +equally valuable + + + align:start position:0% +equally valuable +ends i'm just not going to believe it + + align:start position:0% + + + + align:start position:0% + +fear + + align:start position:0% +fear + + + align:start position:0% +fear +faith + + align:start position:0% + + + + align:start position:0% + +ah + + align:start position:0% +ah + + + align:start position:0% +ah +there is a certain amount of faith in + + align:start position:0% +there is a certain amount of faith in + + + align:start position:0% +there is a certain amount of faith in +all of this uh because there's this + + align:start position:0% +all of this uh because there's this + + + align:start position:0% +all of this uh because there's this +unwritten well it is written it is it is + + align:start position:0% +unwritten well it is written it is it is + + + align:start position:0% +unwritten well it is written it is it is +written and you have to read it when you + + align:start position:0% +written and you have to read it when you + + + align:start position:0% +written and you have to read it when you +read these uh people + + align:start position:0% +read these uh people + + + align:start position:0% +read these uh people +uh they will all say that what we're + + align:start position:0% +uh they will all say that what we're + + + align:start position:0% +uh they will all say that what we're +talking about applies to rational + + align:start position:0% +talking about applies to rational + + + align:start position:0% +talking about applies to rational +persons + + align:start position:0% + + + + align:start position:0% + +which + + align:start position:0% +which + + + align:start position:0% +which +does not apply to children + + align:start position:0% +does not apply to children + + + align:start position:0% +does not apply to children +does not apply to schizophrenics + + align:start position:0% +does not apply to schizophrenics + + + align:start position:0% +does not apply to schizophrenics +but it doesn't apply to a whole lot of + + align:start position:0% +but it doesn't apply to a whole lot of + + + align:start position:0% +but it doesn't apply to a whole lot of +other + + align:start position:0% +other + + + align:start position:0% +other +people it doesn't apply to faith + + align:start position:0% +people it doesn't apply to faith + + + align:start position:0% +people it doesn't apply to faith +and it does not apply there's another + + align:start position:0% +and it does not apply there's another + + + align:start position:0% +and it does not apply there's another +category of person out here or a + + align:start position:0% +category of person out here or a + + + align:start position:0% +category of person out here or a +category + + align:start position:0% +category + + + align:start position:0% +category +that we all find ourselves in from time + + align:start position:0% +that we all find ourselves in from time + + + align:start position:0% +that we all find ourselves in from time +to time + + align:start position:0% +to time + + + align:start position:0% +to time +that's the category when we say i will + + align:start position:0% +that's the category when we say i will + + + align:start position:0% +that's the category when we say i will +allow my emotions to take charge of my + + align:start position:0% +allow my emotions to take charge of my + + + align:start position:0% +allow my emotions to take charge of my +reasons + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +if you don't believe it is there a dance + + align:start position:0% +if you don't believe it is there a dance + + + align:start position:0% +if you don't believe it is there a dance +department here at mit + + align:start position:0% +department here at mit + + + align:start position:0% +department here at mit +is there a art department + + align:start position:0% + + + + align:start position:0% + +in architecture + + align:start position:0% + + + + align:start position:0% + +you'll find that uh + + align:start position:0% +you'll find that uh + + + align:start position:0% +you'll find that uh +there's something more important than + + align:start position:0% +there's something more important than + + + align:start position:0% +there's something more important than +faith and reason + + align:start position:0% +faith and reason + + + align:start position:0% +faith and reason +that's being able to anybody you know a + + align:start position:0% +that's being able to anybody you know a + + + align:start position:0% +that's being able to anybody you know a +frenchman + + align:start position:0% +frenchman + + + align:start position:0% +frenchman +a frenchman a frenchman + + align:start position:0% +a frenchman a frenchman + + + align:start position:0% +a frenchman a frenchman +a friend from france + + align:start position:0% +a friend from france + + + align:start position:0% +a friend from france +talk to a freshman see what they find + + align:start position:0% +talk to a freshman see what they find + + + align:start position:0% +talk to a freshman see what they find +out is the most important thing in life + + align:start position:0% +out is the most important thing in life + + + align:start position:0% +out is the most important thing in life +might not be reason might not be faith + + align:start position:0% +might not be reason might not be faith + + + align:start position:0% +might not be reason might not be faith +either + + align:start position:0% +either + + + align:start position:0% +either +it might be stuff that comes from your + + align:start position:0% +it might be stuff that comes from your + + + align:start position:0% +it might be stuff that comes from your +heart + + align:start position:0% + + + + align:start position:0% + +uh a word that they will use from time + + align:start position:0% +uh a word that they will use from time + + + align:start position:0% +uh a word that they will use from time +to time that i don't like to use because + + align:start position:0% +to time that i don't like to use because + + + align:start position:0% +to time that i don't like to use because +it isn't strong enough + + align:start position:0% +it isn't strong enough + + + align:start position:0% +it isn't strong enough +uh is intuition + + align:start position:0% +uh is intuition + + + align:start position:0% +uh is intuition +but that's not really what it is + + align:start position:0% +but that's not really what it is + + + align:start position:0% +but that's not really what it is +something else + + align:start position:0% +something else + + + align:start position:0% +something else +okay all right here's what i think that + + align:start position:0% +okay all right here's what i think that + + + align:start position:0% +okay all right here's what i think that +uh a + + align:start position:0% +uh a + + + align:start position:0% +uh a +utilitarian will say + + align:start position:0% + + + + align:start position:0% + +uh + + align:start position:0% +uh + + + align:start position:0% +uh +that um + + align:start position:0% +that um + + + align:start position:0% +that um +might have some compulsion + + align:start position:0% +might have some compulsion + + + align:start position:0% +might have some compulsion +uh i invite you to read more + + align:start position:0% +uh i invite you to read more + + + align:start position:0% +uh i invite you to read more +and to bring this up again and take me + + align:start position:0% +and to bring this up again and take me + + + align:start position:0% +and to bring this up again and take me +on + + align:start position:0% +on + + + align:start position:0% +on +in this okay but i think that a + + align:start position:0% +in this okay but i think that a + + + align:start position:0% +in this okay but i think that a +utilitarian will say well look + + align:start position:0% +utilitarian will say well look + + + align:start position:0% +utilitarian will say well look +i didn't make up this whole business of + + align:start position:0% +i didn't make up this whole business of + + + align:start position:0% +i didn't make up this whole business of +morals i went and asked you before i put + + align:start position:0% +morals i went and asked you before i put + + + align:start position:0% +morals i went and asked you before i put +this theory together + + align:start position:0% +this theory together + + + align:start position:0% +this theory together +you told me already what you thought was + + align:start position:0% +you told me already what you thought was + + + align:start position:0% +you told me already what you thought was +were morals and right and wrong all i'm + + align:start position:0% +were morals and right and wrong all i'm + + + align:start position:0% +were morals and right and wrong all i'm +doing is putting it into a logical + + align:start position:0% +doing is putting it into a logical + + + align:start position:0% +doing is putting it into a logical +irrational order + + align:start position:0% +irrational order + + + align:start position:0% +irrational order +so the utilitarian will blame you for + + align:start position:0% +so the utilitarian will blame you for + + + align:start position:0% +so the utilitarian will blame you for +the whole thing + + align:start position:0% + + + + align:start position:0% + +but what is the end + + align:start position:0% +but what is the end + + + align:start position:0% +but what is the end +that doesn't + + align:start position:0% +that doesn't + + + align:start position:0% +that doesn't +i'm not understanding how that solves + + align:start position:0% +i'm not understanding how that solves + + + align:start position:0% +i'm not understanding how that solves +the problem you pointed out right + + align:start position:0% +the problem you pointed out right + + + align:start position:0% +the problem you pointed out right +there's a i think the best way to + + align:start position:0% +there's a i think the best way to + + + align:start position:0% +there's a i think the best way to +explain that one is by uh + + align:start position:0% +explain that one is by uh + + + align:start position:0% +explain that one is by uh +a person uh + + align:start position:0% +a person uh + + + align:start position:0% +a person uh +named schopenhauer + + align:start position:0% +named schopenhauer + + + align:start position:0% +named schopenhauer +okay + + align:start position:0% +okay + + + align:start position:0% +okay +now schopenhauer tells a story + + align:start position:0% +now schopenhauer tells a story + + + align:start position:0% +now schopenhauer tells a story +schopenhauer says he's + + align:start position:0% +schopenhauer says he's + + + align:start position:0% +schopenhauer says he's +walking along one day + + align:start position:0% +walking along one day + + + align:start position:0% +walking along one day +uh and gets to a bridge + + align:start position:0% +uh and gets to a bridge + + + align:start position:0% +uh and gets to a bridge +and there's some other people on the + + align:start position:0% +and there's some other people on the + + + align:start position:0% +and there's some other people on the +bridge + + align:start position:0% +bridge + + + align:start position:0% +bridge +and one person gets up and decides to + + align:start position:0% +and one person gets up and decides to + + + align:start position:0% +and one person gets up and decides to +commit suicide and tries to jump off the + + align:start position:0% +commit suicide and tries to jump off the + + + align:start position:0% +commit suicide and tries to jump off the +bridge + + align:start position:0% +bridge + + + align:start position:0% +bridge +just as he gets uh gets off the bridge + + align:start position:0% +just as he gets uh gets off the bridge + + + align:start position:0% +just as he gets uh gets off the bridge +another person runs over and grabs him + + align:start position:0% +another person runs over and grabs him + + + align:start position:0% +another person runs over and grabs him +by the nape of the neck and holds + + align:start position:0% +by the nape of the neck and holds + + + align:start position:0% +by the nape of the neck and holds +and then everybody else pulls them all + + align:start position:0% +and then everybody else pulls them all + + + align:start position:0% +and then everybody else pulls them all +back in + + align:start position:0% +back in + + + align:start position:0% +back in +and chopin our asked the guy i said + + align:start position:0% +and chopin our asked the guy i said + + + align:start position:0% +and chopin our asked the guy i said +why did you do that why did you risk + + align:start position:0% +why did you do that why did you risk + + + align:start position:0% +why did you do that why did you risk +your life for this guy when + + align:start position:0% +your life for this guy when + + + align:start position:0% +your life for this guy when +you almost went over if we weren't here + + align:start position:0% +you almost went over if we weren't here + + + align:start position:0% +you almost went over if we weren't here +to pull you back you'd have gone too his + + align:start position:0% +to pull you back you'd have gone too his + + + align:start position:0% +to pull you back you'd have gone too his +answer was i could not live with myself + + align:start position:0% +answer was i could not live with myself + + + align:start position:0% +answer was i could not live with myself +if i hadn't tried + + align:start position:0% +if i hadn't tried + + + align:start position:0% +if i hadn't tried +so the point is very much like what you + + align:start position:0% +so the point is very much like what you + + + align:start position:0% +so the point is very much like what you +had said before some people cannot + + align:start position:0% +had said before some people cannot + + + align:start position:0% +had said before some people cannot +separate their individual cells from + + align:start position:0% +separate their individual cells from + + + align:start position:0% +separate their individual cells from +your individual self + + align:start position:0% +your individual self + + + align:start position:0% +your individual self +better stated better stated some people + + align:start position:0% +better stated better stated some people + + + align:start position:0% +better stated better stated some people +cannot separate their feelings of + + align:start position:0% +cannot separate their feelings of + + + align:start position:0% +cannot separate their feelings of +pain and happiness from your feelings as + + align:start position:0% +pain and happiness from your feelings as + + + align:start position:0% +pain and happiness from your feelings as +pain it happens i'm sitting here uh + + align:start position:0% +pain it happens i'm sitting here uh + + + align:start position:0% +pain it happens i'm sitting here uh +eating a hamburger feeling good you're + + align:start position:0% +eating a hamburger feeling good you're + + + align:start position:0% +eating a hamburger feeling good you're +sitting there starving i can't enjoy my + + align:start position:0% +sitting there starving i can't enjoy my + + + align:start position:0% +sitting there starving i can't enjoy my +hamburger + + align:start position:0% +hamburger + + + align:start position:0% +hamburger +so it is some people just do not see + + align:start position:0% +so it is some people just do not see + + + align:start position:0% +so it is some people just do not see +that there is a difference between your + + align:start position:0% +that there is a difference between your + + + align:start position:0% +that there is a difference between your +pain and their own + + align:start position:0% +pain and their own + + + align:start position:0% +pain and their own +it's called empathy + + align:start position:0% +it's called empathy + + + align:start position:0% +it's called empathy +and other things well then you say well + + align:start position:0% +and other things well then you say well + + + align:start position:0% +and other things well then you say well +what about people who are not empathetic + + align:start position:0% +what about people who are not empathetic + + + align:start position:0% +what about people who are not empathetic +now here's what i think a good bentham + + align:start position:0% +now here's what i think a good bentham + + + align:start position:0% +now here's what i think a good bentham +utilitarian would say + + align:start position:0% +utilitarian would say + + + align:start position:0% +utilitarian would say +well + + align:start position:0% +well + + + align:start position:0% +well +this is only the starting point for laws + + align:start position:0% +this is only the starting point for laws + + + align:start position:0% +this is only the starting point for laws +we're going to force you to be this way + + align:start position:0% + + + + align:start position:0% + +okay the whole point for him was to get + + align:start position:0% +okay the whole point for him was to get + + + align:start position:0% +okay the whole point for him was to get +a good sound basis for + + align:start position:0% +a good sound basis for + + + align:start position:0% +a good sound basis for +law that was enforceable + + align:start position:0% + + + + align:start position:0% + +and i really think + + align:start position:0% +and i really think + + + align:start position:0% +and i really think +that a utilitarian + + align:start position:0% +that a utilitarian + + + align:start position:0% +that a utilitarian +who doesn't see it that way is going to + + align:start position:0% +who doesn't see it that way is going to + + + align:start position:0% +who doesn't see it that way is going to +offer you an argument that you won't + + align:start position:0% +offer you an argument that you won't + + + align:start position:0% +offer you an argument that you won't +find compelling + + align:start position:0% + + + + align:start position:0% + +now let's let's let's go back across the + + align:start position:0% +now let's let's let's go back across the + + + align:start position:0% +now let's let's let's go back across the +wall + + align:start position:0% +wall + + + align:start position:0% +wall +uh there was a man who wrote his + + align:start position:0% +uh there was a man who wrote his + + + align:start position:0% +uh there was a man who wrote his +kant wrote his most important piece + + align:start position:0% +kant wrote his most important piece + + + align:start position:0% +kant wrote his most important piece +and if i got it right 17 + + align:start position:0% + + + + align:start position:0% + +around 1776 i was going to say 1780. + + align:start position:0% +around 1776 i was going to say 1780. + + + align:start position:0% +around 1776 i was going to say 1780. +but yeah which one + + align:start position:0% +but yeah which one + + + align:start position:0% +but yeah which one +critique + + align:start position:0% +critique + + + align:start position:0% +critique +so we're talking about the same period + + align:start position:0% +so we're talking about the same period + + + align:start position:0% +so we're talking about the same period +of time + + align:start position:0% + + + + align:start position:0% + +so a lot of things were going on + + align:start position:0% +so a lot of things were going on + + + align:start position:0% +so a lot of things were going on +intellectually in these times + + align:start position:0% +intellectually in these times + + + align:start position:0% +intellectually in these times +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so now we're going to go over to + + align:start position:0% +so now we're going to go over to + + + align:start position:0% +so now we're going to go over to +uh + + align:start position:0% +uh + + + align:start position:0% +uh +i'm going to call it germania + + align:start position:0% +i'm going to call it germania + + + align:start position:0% +i'm going to call it germania +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and we're going to go to a little town + + align:start position:0% +and we're going to go to a little town + + + align:start position:0% +and we're going to go to a little town +called krona's cronie kronigsberg + + align:start position:0% +called krona's cronie kronigsberg + + + align:start position:0% +called krona's cronie kronigsberg +i get that right cronig's bird + + align:start position:0% +i get that right cronig's bird + + + align:start position:0% +i get that right cronig's bird +the o has the um lot on top of + + align:start position:0% +the o has the um lot on top of + + + align:start position:0% +the o has the um lot on top of +know you're german you tell me how to + + align:start position:0% +know you're german you tell me how to + + + align:start position:0% +know you're german you tell me how to +pronounce it + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +and it's a small college town and + + align:start position:0% +and it's a small college town and + + + align:start position:0% +and it's a small college town and +there's a man named man there named + + align:start position:0% +there's a man named man there named + + + align:start position:0% +there's a man named man there named +emmanuel kant + + align:start position:0% +emmanuel kant + + + align:start position:0% +emmanuel kant +and + + align:start position:0% + + + + align:start position:0% + +emmanuel kant uh + + align:start position:0% +emmanuel kant uh + + + align:start position:0% +emmanuel kant uh +in his whole life has never left that + + align:start position:0% +in his whole life has never left that + + + align:start position:0% +in his whole life has never left that +little town + + align:start position:0% + + + + align:start position:0% + +he's going to talk about the nature of + + align:start position:0% +he's going to talk about the nature of + + + align:start position:0% +he's going to talk about the nature of +humanity but he's never left that little + + align:start position:0% +humanity but he's never left that little + + + align:start position:0% +humanity but he's never left that little +town + + align:start position:0% + + + + align:start position:0% + +all right + + align:start position:0% +all right + + + align:start position:0% +all right +um + + align:start position:0% + + + + align:start position:0% + +emmanuel kant + + align:start position:0% + + + + align:start position:0% + +uh + + align:start position:0% +uh + + + align:start position:0% +uh +now here's what i think helps me see + + align:start position:0% +now here's what i think helps me see + + + align:start position:0% +now here's what i think helps me see +what emmanuel kant says + + align:start position:0% +what emmanuel kant says + + + align:start position:0% +what emmanuel kant says +may not help you but try to see it + + align:start position:0% +may not help you but try to see it + + + align:start position:0% +may not help you but try to see it +through my eyes first + + align:start position:0% +through my eyes first + + + align:start position:0% +through my eyes first +then tear it up + + align:start position:0% +then tear it up + + + align:start position:0% +then tear it up +okay + + align:start position:0% +okay + + + align:start position:0% +okay +emanuel kahn was first and foremost a + + align:start position:0% +emanuel kahn was first and foremost a + + + align:start position:0% +emanuel kahn was first and foremost a +professor + + align:start position:0% +professor + + + align:start position:0% +professor +of logic + + align:start position:0% + + + + align:start position:0% + +he was a logician + + align:start position:0% + + + + align:start position:0% + +and + + align:start position:0% +and + + + align:start position:0% +and +he looks at this + + align:start position:0% +he looks at this + + + align:start position:0% +he looks at this +question of teleology about why people + + align:start position:0% +question of teleology about why people + + + align:start position:0% +question of teleology about why people +act in certain ways + + align:start position:0% +act in certain ways + + + align:start position:0% +act in certain ways +and he can find he says that he's just + + align:start position:0% +and he can find he says that he's just + + + align:start position:0% +and he can find he says that he's just +looked at the universe of what everybody + + align:start position:0% +looked at the universe of what everybody + + + align:start position:0% +looked at the universe of what everybody +says about ends and means and he can + + align:start position:0% +says about ends and means and he can + + + align:start position:0% +says about ends and means and he can +find only one end + + align:start position:0% + + + + align:start position:0% + +that human beings are capable of + + align:start position:0% +that human beings are capable of + + + align:start position:0% +that human beings are capable of +and he says that human beings + + align:start position:0% +and he says that human beings + + + align:start position:0% +and he says that human beings +remember that uh + + align:start position:0% +remember that uh + + + align:start position:0% +remember that uh +piece i had up here + + align:start position:0% +piece i had up here + + + align:start position:0% +piece i had up here +about the gothic + + align:start position:0% +about the gothic + + + align:start position:0% +about the gothic +religion + + align:start position:0% +religion + + + align:start position:0% +religion +he says that every human being + + align:start position:0% +he says that every human being + + + align:start position:0% +he says that every human being +has the capacity + + align:start position:0% +has the capacity + + + align:start position:0% +has the capacity +hi + + align:start position:0% +hi + + + align:start position:0% +hi +we ought to hear five of + + align:start position:0% +we ought to hear five of + + + align:start position:0% +we ought to hear five of +yeah + + align:start position:0% +yeah + + + align:start position:0% +yeah +i have a class yeah okay so we're out of + + align:start position:0% +i have a class yeah okay so we're out of + + + align:start position:0% +i have a class yeah okay so we're out of +here five of them + + align:start position:0% +here five of them + + + align:start position:0% +here five of them +um + + align:start position:0% + + + + align:start position:0% + +emmanuel khan says + + align:start position:0% + + + + align:start position:0% + +that + + align:start position:0% +that + + + align:start position:0% +that +every person has the will + + align:start position:0% +every person has the will + + + align:start position:0% +every person has the will +the capability called the will + + align:start position:0% +the capability called the will + + + align:start position:0% +the capability called the will +to do to act + + align:start position:0% +to do to act + + + align:start position:0% +to do to act +and he says now you understand this you + + align:start position:0% +and he says now you understand this you + + + align:start position:0% +and he says now you understand this you +have to understand this + + align:start position:0% +have to understand this + + + align:start position:0% +have to understand this +that that will + + align:start position:0% +that that will + + + align:start position:0% +that that will +is not + + align:start position:0% +is not + + + align:start position:0% +is not +the effect of any other cause + + align:start position:0% +the effect of any other cause + + + align:start position:0% +the effect of any other cause +nobody else + + align:start position:0% +nobody else + + + align:start position:0% +nobody else +including god + + align:start position:0% +including god + + + align:start position:0% +including god +gave you that will + + align:start position:0% +gave you that will + + + align:start position:0% +gave you that will +that was yours + + align:start position:0% +that was yours + + + align:start position:0% +that was yours +that's the end + + align:start position:0% +that's the end + + + align:start position:0% +that's the end +so he says now let's see if we can build + + align:start position:0% +so he says now let's see if we can build + + + align:start position:0% +so he says now let's see if we can build +up an ethical system based on the will + + align:start position:0% +up an ethical system based on the will + + + align:start position:0% +up an ethical system based on the will +notice the will is in the mind + + align:start position:0% +notice the will is in the mind + + + align:start position:0% +notice the will is in the mind +i'm not going out here to make any tests + + align:start position:0% +i'm not going out here to make any tests + + + align:start position:0% +i'm not going out here to make any tests +i've never left this little village + + align:start position:0% +i've never left this little village + + + align:start position:0% +i've never left this little village +not village a little town little college + + align:start position:0% +not village a little town little college + + + align:start position:0% +not village a little town little college +town i don't have to leave i don't have + + align:start position:0% +town i don't have to leave i don't have + + + align:start position:0% +town i don't have to leave i don't have +to get my clipboard and ask anybody + + align:start position:0% +to get my clipboard and ask anybody + + + align:start position:0% +to get my clipboard and ask anybody +anything + + align:start position:0% +anything + + + align:start position:0% +anything +because if it's in my mind it's in yours + + align:start position:0% +because if it's in my mind it's in yours + + + align:start position:0% +because if it's in my mind it's in yours +that i can talk about the mind as a + + align:start position:0% +that i can talk about the mind as a + + + align:start position:0% +that i can talk about the mind as a +universe okay i shouldn't use that word + + align:start position:0% +universe okay i shouldn't use that word + + + align:start position:0% +universe okay i shouldn't use that word +over here okay so he says what about the + + align:start position:0% +over here okay so he says what about the + + + align:start position:0% +over here okay so he says what about the +will + + align:start position:0% +will + + + align:start position:0% +will +all right i have the will + + align:start position:0% + + + + align:start position:0% + +to act this way or that way + + align:start position:0% + + + + align:start position:0% + +now + + align:start position:0% + + + + align:start position:0% + +he's a logician + + align:start position:0% + + + + align:start position:0% + +and he's looking for first principles + + align:start position:0% +and he's looking for first principles + + + align:start position:0% +and he's looking for first principles +like a mathematician would look for + + align:start position:0% +like a mathematician would look for + + + align:start position:0% +like a mathematician would look for +axioms + + align:start position:0% +axioms + + + align:start position:0% +axioms +okay + + align:start position:0% +okay + + + align:start position:0% +okay +he says + + align:start position:0% +he says + + + align:start position:0% +he says +if i have the will + + align:start position:0% +if i have the will + + + align:start position:0% +if i have the will +to act this way or that way + + align:start position:0% + + + + align:start position:0% + +i act + + align:start position:0% +i act + + + align:start position:0% +i act +this way but then i don't act that way + + align:start position:0% +this way but then i don't act that way + + + align:start position:0% +this way but then i don't act that way +why is it that i make this choice + + align:start position:0% +why is it that i make this choice + + + align:start position:0% +why is it that i make this choice +instead of that + + align:start position:0% +instead of that + + + align:start position:0% +instead of that +okay so it's free will + + align:start position:0% +okay so it's free will + + + align:start position:0% +okay so it's free will +but a logician is asking why did i make + + align:start position:0% +but a logician is asking why did i make + + + align:start position:0% +but a logician is asking why did i make +this choice + + align:start position:0% +this choice + + + align:start position:0% +this choice +instead of that + + align:start position:0% + + + + align:start position:0% + +and then he does something that + + align:start position:0% +and then he does something that + + + align:start position:0% +and then he does something that +lets you know how deep he's trying to + + align:start position:0% +lets you know how deep he's trying to + + + align:start position:0% +lets you know how deep he's trying to +get + + align:start position:0% +get + + + align:start position:0% +get +he's saying i have the will + + align:start position:0% +he's saying i have the will + + + align:start position:0% +he's saying i have the will +to hold out this piece of chalk and drop + + align:start position:0% +to hold out this piece of chalk and drop + + + align:start position:0% +to hold out this piece of chalk and drop +it + + align:start position:0% + + + + align:start position:0% + +after that piece of chalk after i let + + align:start position:0% +after that piece of chalk after i let + + + align:start position:0% +after that piece of chalk after i let +that piece of truck + + align:start position:0% +that piece of truck + + + align:start position:0% +that piece of truck +chalk drop + + align:start position:0% +chalk drop + + + align:start position:0% +chalk drop +that piece of chalk it is subject to + + align:start position:0% +that piece of chalk it is subject to + + + align:start position:0% +that piece of chalk it is subject to +some + + align:start position:0% +some + + + align:start position:0% +some +to some laws of nature + + align:start position:0% +to some laws of nature + + + align:start position:0% +to some laws of nature +law of gravitation that govern what + + align:start position:0% +law of gravitation that govern what + + + align:start position:0% +law of gravitation that govern what +happens + + align:start position:0% +happens + + + align:start position:0% +happens +okay + + align:start position:0% +okay + + + align:start position:0% +okay +while my i was acting upon my will + + align:start position:0% +while my i was acting upon my will + + + align:start position:0% +while my i was acting upon my will +my will has some laws + + align:start position:0% +my will has some laws + + + align:start position:0% +my will has some laws +but i invent those laws + + align:start position:0% + + + + align:start position:0% + +somebody else invented + + align:start position:0% +somebody else invented + + + align:start position:0% +somebody else invented +law of gravitation + + align:start position:0% +law of gravitation + + + align:start position:0% +law of gravitation +but i invent the laws by which i will + + align:start position:0% +but i invent the laws by which i will + + + align:start position:0% +but i invent the laws by which i will +choose to do this instead of doing that + + align:start position:0% + + + + align:start position:0% + +all right + + align:start position:0% + + + + align:start position:0% + +which laws what laws shall i adopt + + align:start position:0% +which laws what laws shall i adopt + + + align:start position:0% +which laws what laws shall i adopt +then he asks one more question and gets + + align:start position:0% +then he asks one more question and gets + + + align:start position:0% +then he asks one more question and gets +to the final part + + align:start position:0% + + + + align:start position:0% + +well i i want some basic laws i want the + + align:start position:0% +well i i want some basic laws i want the + + + align:start position:0% +well i i want some basic laws i want the +fundamental laws i want something that's + + align:start position:0% +fundamental laws i want something that's + + + align:start position:0% +fundamental laws i want something that's +on the level of an axiom in mathematics + + align:start position:0% +on the level of an axiom in mathematics + + + align:start position:0% +on the level of an axiom in mathematics +okay + + align:start position:0% + + + + align:start position:0% + +and what he says is + + align:start position:0% + + + + align:start position:0% + +what he says is + + align:start position:0% +what he says is + + + align:start position:0% +what he says is +see if i can put it in these in the + + align:start position:0% +see if i can put it in these in the + + + align:start position:0% +see if i can put it in these in the +right words because + + align:start position:0% +right words because + + + align:start position:0% +right words because +uh + + align:start position:0% +uh + + + align:start position:0% +uh +this has to be done right + + align:start position:0% +this has to be done right + + + align:start position:0% +this has to be done right +um + + align:start position:0% + + + + align:start position:0% + +what he says is that i want some laws + + align:start position:0% +what he says is that i want some laws + + + align:start position:0% +what he says is that i want some laws +that tell me + + align:start position:0% +that tell me + + + align:start position:0% +that tell me +what + + align:start position:0% +what + + + align:start position:0% +what +i should + + align:start position:0% +i should + + + align:start position:0% +i should +do + + align:start position:0% +do + + + align:start position:0% +do +or tell me what i should not do + + align:start position:0% +or tell me what i should not do + + + align:start position:0% +or tell me what i should not do +i'm going to call these imperatives + + align:start position:0% + + + + align:start position:0% + +now here's the subtlety about + + align:start position:0% +now here's the subtlety about + + + align:start position:0% +now here's the subtlety about +these imperatives + + align:start position:0% +these imperatives + + + align:start position:0% +these imperatives +now listen to me careful this is a + + align:start position:0% +now listen to me careful this is a + + + align:start position:0% +now listen to me careful this is a +subtlety i think it's a subtlety because + + align:start position:0% +subtlety i think it's a subtlety because + + + align:start position:0% +subtlety i think it's a subtlety because +philosophers tend to take it for granted + + align:start position:0% +philosophers tend to take it for granted + + + align:start position:0% +philosophers tend to take it for granted +i think it's the difference between life + + align:start position:0% +i think it's the difference between life + + + align:start position:0% +i think it's the difference between life +and death death for us in the class + + align:start position:0% + + + + align:start position:0% + +an imperative is something that you + + align:start position:0% +an imperative is something that you + + + align:start position:0% +an imperative is something that you +should do + + align:start position:0% +should do + + + align:start position:0% +should do +all of the time + + align:start position:0% +all of the time + + + align:start position:0% +all of the time +not when the situation arises that's + + align:start position:0% +not when the situation arises that's + + + align:start position:0% +not when the situation arises that's +empirical + + align:start position:0% + + + + align:start position:0% + +you should never lie + + align:start position:0% +you should never lie + + + align:start position:0% +you should never lie +not + + align:start position:0% +not + + + align:start position:0% +not +wait till the occasion comes you should + + align:start position:0% +wait till the occasion comes you should + + + align:start position:0% +wait till the occasion comes you should +what can i write down as an imperative + + align:start position:0% +what can i write down as an imperative + + + align:start position:0% +what can i write down as an imperative +that i should always do + + align:start position:0% +that i should always do + + + align:start position:0% +that i should always do +or that i should never do + + align:start position:0% +or that i should never do + + + align:start position:0% +or that i should never do +that's an imperative + + align:start position:0% + + + + align:start position:0% + +if i should treat + + align:start position:0% +if i should treat + + + align:start position:0% +if i should treat +if i should try to maximize + + align:start position:0% +if i should try to maximize + + + align:start position:0% +if i should try to maximize +your happiness + + align:start position:0% + + + + align:start position:0% + +in order that we all maximize our habits + + align:start position:0% +in order that we all maximize our habits + + + align:start position:0% +in order that we all maximize our habits +then emmanuel khan is going to say well + + align:start position:0% +then emmanuel khan is going to say well + + + align:start position:0% +then emmanuel khan is going to say well +that's an empirical test that lasts for + + align:start position:0% +that's an empirical test that lasts for + + + align:start position:0% +that's an empirical test that lasts for +that particular instance that's not a + + align:start position:0% +that particular instance that's not a + + + align:start position:0% +that particular instance that's not a +general you can't that's not a general + + align:start position:0% +general you can't that's not a general + + + align:start position:0% +general you can't that's not a general +principle of of of the will + + align:start position:0% +principle of of of the will + + + align:start position:0% +principle of of of the will +what is a general principle of the will + + align:start position:0% + + + + align:start position:0% + +he's a logician + + align:start position:0% +he's a logician + + + align:start position:0% +he's a logician +his logic + + align:start position:0% +his logic + + + align:start position:0% +his logic +what can i do here's the way he would + + align:start position:0% +what can i do here's the way he would + + + align:start position:0% +what can i do here's the way he would +like his way emmanuel kant would say why + + align:start position:0% +like his way emmanuel kant would say why + + + align:start position:0% +like his way emmanuel kant would say why +you should never lie + + align:start position:0% + + + + align:start position:0% + +why should you no no i got a battle + + align:start position:0% +why should you no no i got a battle + + + align:start position:0% +why should you no no i got a battle +steal why should you never steal why + + align:start position:0% +steal why should you never steal why + + + align:start position:0% +steal why should you never steal why +should god i better stay why should you + + align:start position:0% +should god i better stay why should you + + + align:start position:0% +should god i better stay why should you +never steal + + align:start position:0% +never steal + + + align:start position:0% +never steal +why should i always act so that i never + + align:start position:0% +why should i always act so that i never + + + align:start position:0% +why should i always act so that i never +steal + + align:start position:0% +steal + + + align:start position:0% +steal +every day + + align:start position:0% +every day + + + align:start position:0% +every day +all the time + + align:start position:0% +all the time + + + align:start position:0% +all the time +now here's the way kant would argue that + + align:start position:0% +now here's the way kant would argue that + + + align:start position:0% +now here's the way kant would argue that +out + + align:start position:0% +out + + + align:start position:0% +out +got nothing to do with whether or not it + + align:start position:0% +got nothing to do with whether or not it + + + align:start position:0% +got nothing to do with whether or not it +makes other people mad + + align:start position:0% +makes other people mad + + + align:start position:0% +makes other people mad +and whether or not they're gonna hurt me + + align:start position:0% +and whether or not they're gonna hurt me + + + align:start position:0% +and whether or not they're gonna hurt me +so that i will not maximize my pleasure + + align:start position:0% +so that i will not maximize my pleasure + + + align:start position:0% +so that i will not maximize my pleasure +he's a logician + + align:start position:0% +he's a logician + + + align:start position:0% +he's a logician +kant will say that stealing + + align:start position:0% +kant will say that stealing + + + align:start position:0% +kant will say that stealing +implies property + + align:start position:0% +implies property + + + align:start position:0% +implies property +and if i steal all of your property and + + align:start position:0% +and if i steal all of your property and + + + align:start position:0% +and if i steal all of your property and +all of your property and all your + + align:start position:0% +all of your property and all your + + + align:start position:0% +all of your property and all your +property and all your property and all + + align:start position:0% +property and all your property and all + + + align:start position:0% +property and all your property and all +your property the time will come when i + + align:start position:0% +your property the time will come when i + + + align:start position:0% +your property the time will come when i +cannot act + + align:start position:0% + + + + align:start position:0% + +that i will uh steal + + align:start position:0% +that i will uh steal + + + align:start position:0% +that i will uh steal +because there's nothing for me to steal + + align:start position:0% + + + + align:start position:0% + +if i say that i can see how he's let me + + align:start position:0% +if i say that i can see how he's let me + + + align:start position:0% +if i say that i can see how he's let me +say that again can you say it better + + align:start position:0% +say that again can you say it better + + + align:start position:0% +say that again can you say it better +so you're saying the choice is the + + align:start position:0% +so you're saying the choice is the + + + align:start position:0% +so you're saying the choice is the +imperative is either you should not + + align:start position:0% +imperative is either you should not + + + align:start position:0% +imperative is either you should not +steal all the time or you shouldn't + + align:start position:0% +steal all the time or you shouldn't + + + align:start position:0% +steal all the time or you shouldn't +steal all the time right and if you go + + align:start position:0% +steal all the time right and if you go + + + align:start position:0% +steal all the time right and if you go +with you should steal all the time + + align:start position:0% +with you should steal all the time + + + align:start position:0% +with you should steal all the time +when you can never do that anymore + + align:start position:0% +when you can never do that anymore + + + align:start position:0% +when you can never do that anymore +logically but if you go with you should + + align:start position:0% +logically but if you go with you should + + + align:start position:0% +logically but if you go with you should +not steal + + align:start position:0% +not steal + + + align:start position:0% +not steal +for the for one's entire life right it + + align:start position:0% +for the for one's entire life right it + + + align:start position:0% +for the for one's entire life right it +is always possible it's always possible + + align:start position:0% +is always possible it's always possible + + + align:start position:0% +is always possible it's always possible +not to steal + + align:start position:0% +not to steal + + + align:start position:0% +not to steal +logically okay logically meaning from + + align:start position:0% +logically okay logically meaning from + + + align:start position:0% +logically okay logically meaning from +the branch + + align:start position:0% +the branch + + + align:start position:0% +the branch +of learn the learned discipline called + + align:start position:0% +of learn the learned discipline called + + + align:start position:0% +of learn the learned discipline called +logic + + align:start position:0% +logic + + + align:start position:0% +logic +okay not in terms of something genetic + + align:start position:0% +okay not in terms of something genetic + + + align:start position:0% +okay not in terms of something genetic +that we call reasoning out of the brain + + align:start position:0% +that we call reasoning out of the brain + + + align:start position:0% +that we call reasoning out of the brain +and people can come up with i'm talking + + align:start position:0% +and people can come up with i'm talking + + + align:start position:0% +and people can come up with i'm talking +about opening a book that has logic on + + align:start position:0% +about opening a book that has logic on + + + align:start position:0% +about opening a book that has logic on +the in the title + + align:start position:0% +the in the title + + + align:start position:0% +the in the title +okay + + align:start position:0% +okay + + + align:start position:0% +okay +all right he's a logician + + align:start position:0% +all right he's a logician + + + align:start position:0% +all right he's a logician +so a lot so he is going to say that the + + align:start position:0% +so a lot so he is going to say that the + + + align:start position:0% +so a lot so he is going to say that the +fundamental principles + + align:start position:0% +fundamental principles + + + align:start position:0% +fundamental principles +are + + align:start position:0% +are + + + align:start position:0% +are +principles of logic + + align:start position:0% +principles of logic + + + align:start position:0% +principles of logic +and then he's going to say + + align:start position:0% +and then he's going to say + + + align:start position:0% +and then he's going to say +that everybody should reason that way + + align:start position:0% +that everybody should reason that way + + + align:start position:0% +that everybody should reason that way +look at logic now + + align:start position:0% +look at logic now + + + align:start position:0% +look at logic now +logic is not going to give you some + + align:start position:0% +logic is not going to give you some + + + align:start position:0% +logic is not going to give you some +alternatives not all that's not always + + align:start position:0% +alternatives not all that's not always + + + align:start position:0% +alternatives not all that's not always +true + + align:start position:0% +true + + + align:start position:0% +true +but the basic ideas that he's talking + + align:start position:0% +but the basic ideas that he's talking + + + align:start position:0% +but the basic ideas that he's talking +about when it comes to imperatives + + align:start position:0% +about when it comes to imperatives + + + align:start position:0% +about when it comes to imperatives +is always true + + align:start position:0% +is always true + + + align:start position:0% +is always true +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so what he is trying to do is give you + + align:start position:0% +so what he is trying to do is give you + + + align:start position:0% +so what he is trying to do is give you +some imperatives the kind of imperative + + align:start position:0% +some imperatives the kind of imperative + + + align:start position:0% +some imperatives the kind of imperative +where i said + + align:start position:0% +where i said + + + align:start position:0% +where i said +uh + + align:start position:0% +uh + + + align:start position:0% +uh +well + + align:start position:0% +well + + + align:start position:0% +well +do x because + + align:start position:0% +do x because + + + align:start position:0% +do x because +uh y will help maximize your pleasure + + align:start position:0% +uh y will help maximize your pleasure + + + align:start position:0% +uh y will help maximize your pleasure +he's going to call that a hypothetical + + align:start position:0% +he's going to call that a hypothetical + + + align:start position:0% +he's going to call that a hypothetical +imperative + + align:start position:0% +imperative + + + align:start position:0% +imperative +never lie he's going to call that guess + + align:start position:0% +never lie he's going to call that guess + + + align:start position:0% +never lie he's going to call that guess +what + + align:start position:0% +what + + + align:start position:0% +what +categorical imperative + + align:start position:0% +categorical imperative + + + align:start position:0% +categorical imperative +i want you to know those terms + + align:start position:0% +i want you to know those terms + + + align:start position:0% +i want you to know those terms +the categorical imperative + + align:start position:0% + + + + align:start position:0% + +so he's going to build up a system of + + align:start position:0% +so he's going to build up a system of + + + align:start position:0% +so he's going to build up a system of +logic + + align:start position:0% +logic + + + align:start position:0% +logic +based on the equivalence of axioms + + align:start position:0% +based on the equivalence of axioms + + + align:start position:0% +based on the equivalence of axioms +called these categorical imperatives + + align:start position:0% + + + + align:start position:0% + +and that those imperatives are + + align:start position:0% +and that those imperatives are + + + align:start position:0% +and that those imperatives are +imperative upon you all of the time + + align:start position:0% +imperative upon you all of the time + + + align:start position:0% +imperative upon you all of the time +by reason of logic + + align:start position:0% + + + + align:start position:0% + +right my last piece on this is + + align:start position:0% +right my last piece on this is + + + align:start position:0% +right my last piece on this is +the same question uh belligerent + + align:start position:0% +the same question uh belligerent + + + align:start position:0% +the same question uh belligerent +question i asked of the utilitarian + + align:start position:0% +question i asked of the utilitarian + + + align:start position:0% +question i asked of the utilitarian +why should i + + align:start position:0% +why should i + + + align:start position:0% +why should i +maximize your + + align:start position:0% +maximize your + + + align:start position:0% +maximize your +happiness + + align:start position:0% +happiness + + + align:start position:0% +happiness +or the happiness of all of the affected + + align:start position:0% +or the happiness of all of the affected + + + align:start position:0% +or the happiness of all of the affected +parties i'm going to ask kant + + align:start position:0% +parties i'm going to ask kant + + + align:start position:0% +parties i'm going to ask kant +all right + + align:start position:0% +all right + + + align:start position:0% +all right +why should i be logical + + align:start position:0% + + + + align:start position:0% + +i'll tell you what khan is going to say + + align:start position:0% +i'll tell you what khan is going to say + + + align:start position:0% +i'll tell you what khan is going to say +khan is going to go all the way back to + + align:start position:0% +khan is going to go all the way back to + + + align:start position:0% +khan is going to go all the way back to +the stoics now for me those were the + + align:start position:0% +the stoics now for me those were the + + + align:start position:0% +the stoics now for me those were the +real philosophers + + align:start position:0% +real philosophers + + + align:start position:0% +real philosophers +the stoics + + align:start position:0% +the stoics + + + align:start position:0% +the stoics +not because their ideas were any good + + align:start position:0% +not because their ideas were any good + + + align:start position:0% +not because their ideas were any good +but because + + align:start position:0% +but because + + + align:start position:0% +but because +they did not eat + + align:start position:0% +they did not eat + + + align:start position:0% +they did not eat +unless they stood up + + align:start position:0% +unless they stood up + + + align:start position:0% +unless they stood up +in a crowd and debated a point + + align:start position:0% +in a crowd and debated a point + + + align:start position:0% +in a crowd and debated a point +and if they won the crowd will give them + + align:start position:0% +and if they won the crowd will give them + + + align:start position:0% +and if they won the crowd will give them +some money that's the only way they can + + align:start position:0% +some money that's the only way they can + + + align:start position:0% +some money that's the only way they can +feed themselves + + align:start position:0% +feed themselves + + + align:start position:0% +feed themselves +so that's from real philosophy + + align:start position:0% +so that's from real philosophy + + + align:start position:0% +so that's from real philosophy +where you say you say joel that's all + + align:start position:0% +where you say you say joel that's all + + + align:start position:0% +where you say you say joel that's all +well i mean to + + align:start position:0% +well i mean to + + + align:start position:0% +well i mean to +convince people that's that's a + + align:start position:0% +convince people that's that's a + + + align:start position:0% +convince people that's that's a +politician's job + + align:start position:0% +politician's job + + + align:start position:0% +politician's job +okay + + align:start position:0% +okay + + + align:start position:0% +okay +all right + + align:start position:0% +all right + + + align:start position:0% +all right +uh + + align:start position:0% +uh + + + align:start position:0% +uh +so uh there was this story about this uh + + align:start position:0% +so uh there was this story about this uh + + + align:start position:0% +so uh there was this story about this uh +stoic + + align:start position:0% +stoic + + + align:start position:0% +stoic +talking about reason and logic + + align:start position:0% +talking about reason and logic + + + align:start position:0% +talking about reason and logic +and somebody in the crowd said wait a + + align:start position:0% +and somebody in the crowd said wait a + + + align:start position:0% +and somebody in the crowd said wait a +minute hold on hold on put his hands + + align:start position:0% +minute hold on hold on put his hands + + + align:start position:0% +minute hold on hold on put his hands +folded his hands across his chest + + align:start position:0% +folded his hands across his chest + + + align:start position:0% +folded his hands across his chest +became very confident looked at that + + align:start position:0% +became very confident looked at that + + + align:start position:0% +became very confident looked at that +philosopher and said + + align:start position:0% +philosopher and said + + + align:start position:0% +philosopher and said +why should i be logical + + align:start position:0% +why should i be logical + + + align:start position:0% +why should i be logical +and the philosopher said + + align:start position:0% +and the philosopher said + + + align:start position:0% +and the philosopher said +do you want a logical answer + + align:start position:0% + + + + align:start position:0% + +the answer was yes + + align:start position:0% +the answer was yes + + + align:start position:0% +the answer was yes +the basic idea was + + align:start position:0% +the basic idea was + + + align:start position:0% +the basic idea was +you should be logical because you compel + + align:start position:0% +you should be logical because you compel + + + align:start position:0% +you should be logical because you compel +me to be logical + + align:start position:0% +me to be logical + + + align:start position:0% +me to be logical +you're going to compel all of us to be + + align:start position:0% +you're going to compel all of us to be + + + align:start position:0% +you're going to compel all of us to be +logical how you get to be so high and + + align:start position:0% +logical how you get to be so high and + + + align:start position:0% +logical how you get to be so high and +mighty that you can be the only one in + + align:start position:0% +mighty that you can be the only one in + + + align:start position:0% +mighty that you can be the only one in +here who's not logical + + align:start position:0% +here who's not logical + + + align:start position:0% +here who's not logical +okay so that's what he means when he + + align:start position:0% +okay so that's what he means when he + + + align:start position:0% +okay so that's what he means when he +says universal + + align:start position:0% +says universal + + + align:start position:0% +says universal +it's got to apply + + align:start position:0% +it's got to apply + + + align:start position:0% +it's got to apply +whatever you do has got to apply to + + align:start position:0% +whatever you do has got to apply to + + + align:start position:0% +whatever you do has got to apply to +everybody + + align:start position:0% + + + + align:start position:0% + +so when you make these analyses + + align:start position:0% +so when you make these analyses + + + align:start position:0% +so when you make these analyses +and we + + align:start position:0% +and we + + + align:start position:0% +and we +of of the a7d case + + align:start position:0% +of of the a7d case + + + align:start position:0% +of of the a7d case +when you get to the + + align:start position:0% + + + + align:start position:0% + +deontological analysis + + align:start position:0% +deontological analysis + + + align:start position:0% +deontological analysis +don't give me anything that tests + + align:start position:0% +don't give me anything that tests + + + align:start position:0% +don't give me anything that tests +facts don't give me any + + align:start position:0% +facts don't give me any + + + align:start position:0% +facts don't give me any +tests based on facts + + align:start position:0% +tests based on facts + + + align:start position:0% +tests based on facts +try your best i i'm + + align:start position:0% +try your best i i'm + + + align:start position:0% +try your best i i'm +going to assume that you haven't had a + + align:start position:0% +going to assume that you haven't had a + + + align:start position:0% +going to assume that you haven't had a +formal course in logic + + align:start position:0% +formal course in logic + + + align:start position:0% +formal course in logic +that's okay + + align:start position:0% +that's okay + + + align:start position:0% +that's okay +at least give it a try + + align:start position:0% +at least give it a try + + + align:start position:0% +at least give it a try +go back and see if you can put this + + align:start position:0% +go back and see if you can put this + + + align:start position:0% +go back and see if you can put this +thing + + align:start position:0% +thing + + + align:start position:0% +thing +in logical terms all right if you can't + + align:start position:0% +in logical terms all right if you can't + + + align:start position:0% +in logical terms all right if you can't +say so + + align:start position:0% +say so + + + align:start position:0% +say so +but say that kant would you don't know + + align:start position:0% +but say that kant would you don't know + + + align:start position:0% +but say that kant would you don't know +how that's what he would do + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +all right now since time is just i i + + align:start position:0% +all right now since time is just i i + + + align:start position:0% +all right now since time is just i i +calculated i got one more minute + + align:start position:0% +calculated i got one more minute + + + align:start position:0% +calculated i got one more minute +all right i promise to do something that + + align:start position:0% +all right i promise to do something that + + + align:start position:0% +all right i promise to do something that +i didn't do yet and that was put the + + align:start position:0% +i didn't do yet and that was put the + + + align:start position:0% +i didn't do yet and that was put the +grades + + align:start position:0% +grades + + + align:start position:0% +grades +uh and uh + + align:start position:0% +uh and uh + + + align:start position:0% +uh and uh +dr moses um + + align:start position:0% +dr moses um + + + align:start position:0% +dr moses um +uh + + align:start position:0% +uh + + + align:start position:0% +uh +presentation + + align:start position:0% +presentation + + + align:start position:0% +presentation +in the email okay i'm gonna do it today + + align:start position:0% +in the email okay i'm gonna do it today + + + align:start position:0% +in the email okay i'm gonna do it today +tomorrow gotta cover that + + align:start position:0% +tomorrow gotta cover that + + + align:start position:0% +tomorrow gotta cover that +and give me this homework on tuesday + + align:start position:0% +and give me this homework on tuesday + + + align:start position:0% +and give me this homework on tuesday +and then we'll start talking about some + + align:start position:0% +and then we'll start talking about some + + + align:start position:0% +and then we'll start talking about some +um + + align:start position:0% +um + + + align:start position:0% +um +some matters of the calendar + + align:start position:0% +some matters of the calendar + + + align:start position:0% +some matters of the calendar +when the test is coming up and all of + + align:start position:0% +when the test is coming up and all of + + + align:start position:0% +when the test is coming up and all of +that kind of stuff + + align:start position:0% + + + + align:start position:0% + +good + + align:start position:0% +good + + + align:start position:0% +good +yes + + align:start position:0% +yes + + + align:start position:0% +yes +question maybe it's not quickly yeah in + + align:start position:0% +question maybe it's not quickly yeah in + + + align:start position:0% +question maybe it's not quickly yeah in +terms of the + + align:start position:0% +terms of the + + + align:start position:0% +terms of the +imperatives + + align:start position:0% +imperatives + + + align:start position:0% +imperatives +is there a difference between having an + + align:start position:0% +is there a difference between having an + + + align:start position:0% +is there a difference between having an +imperative and the ability to fulfill + + align:start position:0% +imperative and the ability to fulfill + + + align:start position:0% +imperative and the ability to fulfill +the impairment so for example if + + align:start position:0% +the impairment so for example if + + + align:start position:0% +the impairment so for example if +the imperative is i'm going to steal + + align:start position:0% +the imperative is i'm going to steal + + + align:start position:0% +the imperative is i'm going to steal +and i'm always going to steal + + align:start position:0% +and i'm always going to steal + + + align:start position:0% +and i'm always going to steal +and maybe there's some point in time + + align:start position:0% +and maybe there's some point in time + + + align:start position:0% +and maybe there's some point in time +when there's nothing not just you but i + + align:start position:0% +when there's nothing not just you but i + + + align:start position:0% +when there's nothing not just you but i +can still have the imperative that i'm + + align:start position:0% +can still have the imperative that i'm + + + align:start position:0% +can still have the imperative that i'm +gonna steal just that i can't fulfill it + + align:start position:0% +gonna steal just that i can't fulfill it + + + align:start position:0% +gonna steal just that i can't fulfill it +there's nothing left to steal until + + align:start position:0% +there's nothing left to steal until + + + align:start position:0% +there's nothing left to steal until +someone makes something and then i'll + + align:start position:0% +someone makes something and then i'll + + + align:start position:0% +someone makes something and then i'll +steal it right so is there a difference + + align:start position:0% +steal it right so is there a difference + + + align:start position:0% +steal it right so is there a difference +between just having a party with + + align:start position:0% +between just having a party with + + + align:start position:0% +between just having a party with +fulfillment + + align:start position:0% + + + + align:start position:0% + +right now uh i'm not going to answer + + align:start position:0% +right now uh i'm not going to answer + + + align:start position:0% +right now uh i'm not going to answer +your question directly + + align:start position:0% +your question directly + + + align:start position:0% +your question directly +because that presumes that there's uh + + align:start position:0% +because that presumes that there's uh + + + align:start position:0% +because that presumes that there's uh +that there's a unique answer to this to + + align:start position:0% +that there's a unique answer to this to + + + align:start position:0% +that there's a unique answer to this to +your question what i'm going to do is + + align:start position:0% +your question what i'm going to do is + + + align:start position:0% +your question what i'm going to do is +say but i think + + align:start position:0% +say but i think + + + align:start position:0% +say but i think +kant and other + + align:start position:0% +kant and other + + + align:start position:0% +kant and other +uh + + align:start position:0% + + + + align:start position:0% + +logists will say + + align:start position:0% +logists will say + + + align:start position:0% +logists will say +um + + align:start position:0% +um + + + align:start position:0% +um +what they will say is that uh they're + + align:start position:0% +what they will say is that uh they're + + + align:start position:0% +what they will say is that uh they're +gonna assume + + align:start position:0% +gonna assume + + + align:start position:0% +gonna assume +that the will + + align:start position:0% +that the will + + + align:start position:0% +that the will +at first it's all powerful they're not + + align:start position:0% +at first it's all powerful they're not + + + align:start position:0% +at first it's all powerful they're not +going to limit that right now + + align:start position:0% +going to limit that right now + + + align:start position:0% +going to limit that right now +and say that you have the power to do + + align:start position:0% +and say that you have the power to do + + + align:start position:0% +and say that you have the power to do +these things the question is will you + + align:start position:0% +these things the question is will you + + + align:start position:0% +these things the question is will you +make the choice + + align:start position:0% +make the choice + + + align:start position:0% +make the choice +to do it + + align:start position:0% +to do it + + + align:start position:0% +to do it +so they're going to eliminate that eye + + align:start position:0% +so they're going to eliminate that eye + + + align:start position:0% +so they're going to eliminate that eye +priority i shouldn't sit up + + align:start position:0% +priority i shouldn't sit up + + + align:start position:0% +priority i shouldn't sit up +they're going to eliminate that before + + align:start position:0% +they're going to eliminate that before + + + align:start position:0% +they're going to eliminate that before +they get into the argument + + align:start position:0% +they get into the argument + + + align:start position:0% +they get into the argument +um + + align:start position:0% +um + + + align:start position:0% +um +the rest of us are going to have to deal + + align:start position:0% +the rest of us are going to have to deal + + + align:start position:0% +the rest of us are going to have to deal +with that on a case-by-case basis + + align:start position:0% +with that on a case-by-case basis + + + align:start position:0% +with that on a case-by-case basis +and let's see how far you can make that + + align:start position:0% +and let's see how far you can make that + + + align:start position:0% +and let's see how far you can make that +argument and the question is can you + + align:start position:0% +argument and the question is can you + + + align:start position:0% +argument and the question is can you +make it compelling now just like dr + + align:start position:0% +make it compelling now just like dr + + + align:start position:0% +make it compelling now just like dr +mozambique we're talking at the + + align:start position:0% +mozambique we're talking at the + + + align:start position:0% +mozambique we're talking at the +beginning of the class + + align:start position:0% +beginning of the class + + + align:start position:0% +beginning of the class +you could probably make that case + + align:start position:0% +you could probably make that case + + + align:start position:0% +you could probably make that case +um i'm going to be + + align:start position:0% +um i'm going to be + + + align:start position:0% +um i'm going to be +you could probably you'll be you'll be + + align:start position:0% +you could probably you'll be you'll be + + + align:start position:0% +you could probably you'll be you'll be +more likely to make that case in germany + + align:start position:0% +more likely to make that case in germany + + + align:start position:0% +more likely to make that case in germany +than you would in it + + align:start position:0% + + + + align:start position:0% + +today even now the world is globalizing + + align:start position:0% +today even now the world is globalizing + + + align:start position:0% +today even now the world is globalizing +and it doesn't apply to everybody + + align:start position:0% +and it doesn't apply to everybody + + + align:start position:0% +and it doesn't apply to everybody +okay but it depends on who you're + + align:start position:0% +okay but it depends on who you're + + + align:start position:0% +okay but it depends on who you're +talking to there's some orientations + + align:start position:0% +talking to there's some orientations + + + align:start position:0% +talking to there's some orientations +that are going to seem more sensitive + + align:start position:0% +that are going to seem more sensitive + + + align:start position:0% +that are going to seem more sensitive +you're not going to make a utilitarian + + align:start position:0% +you're not going to make a utilitarian + + + align:start position:0% +you're not going to make a utilitarian +culture is not going to see any point + + align:start position:0% + + + + align:start position:0% + +we can have a brainstorming discussion + + align:start position:0% +we can have a brainstorming discussion + + + align:start position:0% +we can have a brainstorming discussion +next time we can devote most of the + + align:start position:0% +next time we can devote most of the + + + align:start position:0% +next time we can devote most of the +class to that i won't talk most of it + + align:start position:0% +class to that i won't talk most of it + + + align:start position:0% +class to that i won't talk most of it +how about that + + align:start position:0% + + + + align:start position:0% + +right + + align:start position:0% +right + + + align:start position:0% +right +thank you all very much + + align:start position:0% +thank you all very much + + + align:start position:0% +thank you all very much +you got something for me + + align:start position:0% +you got something for me + + + align:start position:0% +you got something for me +um i was just gonna ask if it would + + align:start position:0% +um i was just gonna ask if it would + + + align:start position:0% +um i was just gonna ask if it would +i know the first time we did a little + + align:start position:0% +i know the first time we did a little + + + align:start position:0% +i know the first time we did a little +paragraph about the a7d case we weren't + + align:start position:0% +paragraph about the a7d case we weren't + + + align:start position:0% +paragraph about the a7d case we weren't +supposed to like do a lot of reading or + + align:start position:0% +supposed to like do a lot of reading or + + + align:start position:0% +supposed to like do a lot of reading or +look at examples right is it okay to do + + align:start position:0% +look at examples right is it okay to do + + + align:start position:0% +look at examples right is it okay to do +that now like to use our book + + align:start position:0% +that now like to use our book + + + align:start position:0% +that now like to use our book +a lot of reading means use the book and + + align:start position:0% +a lot of reading means use the book and + + + align:start position:0% +a lot of reading means use the book and +use at least one other reference right + + align:start position:0% +use at least one other reference right + + + align:start position:0% +use at least one other reference right +okay that's all that means right now + + align:start position:0% +okay that's all that means right now + + + align:start position:0% +okay that's all that means right now +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and it means chapter four okay that's + + align:start position:0% +and it means chapter four okay that's + + + align:start position:0% +and it means chapter four okay that's +all it means thanks \ No newline at end of file diff --git a/iqSMRO78UD0.txt b/iqSMRO78UD0.txt new file mode 100644 index 0000000000000000000000000000000000000000..1fcfcf43f4b2350bad50d0aa4a0c1e685acd6a36 --- /dev/null +++ b/iqSMRO78UD0.txt @@ -0,0 +1,14851 @@ +align:start position:0% + +okay so let's start uh thank you + + align:start position:0% +okay so let's start uh thank you + + + align:start position:0% +okay so let's start uh thank you +everyone for coming uh this is going to + + align:start position:0% +everyone for coming uh this is going to + + + align:start position:0% +everyone for coming uh this is going to +be a advanced class on cryptography + + align:start position:0% +be a advanced class on cryptography + + + align:start position:0% +be a advanced class on cryptography +those who do not have background on + + align:start position:0% +those who do not have background on + + + align:start position:0% +those who do not have background on +cryptography it's okay it's not actually + + align:start position:0% +cryptography it's okay it's not actually + + + align:start position:0% +cryptography it's okay it's not actually +hardcore cryptography this is actually a + + align:start position:0% +hardcore cryptography this is actually a + + + align:start position:0% +hardcore cryptography this is actually a +class on the evolution of proofs in + + align:start position:0% +class on the evolution of proofs in + + + align:start position:0% +class on the evolution of proofs in +computer science so this class is really + + align:start position:0% +computer science so this class is really + + + align:start position:0% +computer science so this class is really +about proofs uh that's what we're going + + align:start position:0% +about proofs uh that's what we're going + + + align:start position:0% +about proofs uh that's what we're going +to learn and kind of how kind of proofs + + align:start position:0% +to learn and kind of how kind of proofs + + + align:start position:0% +to learn and kind of how kind of proofs +evolved with the years starting from + + align:start position:0% +evolved with the years starting from + + + align:start position:0% +evolved with the years starting from +kind of the 80s mid 80s all the way to + + align:start position:0% +kind of the 80s mid 80s all the way to + + + align:start position:0% +kind of the 80s mid 80s all the way to +today and how we think about proofs + + align:start position:0% +today and how we think about proofs + + + align:start position:0% +today and how we think about proofs +differently today so this is uh what + + align:start position:0% +differently today so this is uh what + + + align:start position:0% +differently today so this is uh what +this class is about actually before I I + + align:start position:0% +this class is about actually before I I + + + align:start position:0% +this class is about actually before I I +go into kind of the content of the class + + align:start position:0% +go into kind of the content of the class + + + align:start position:0% +go into kind of the content of the class +and what what I'm going to be teaching + + align:start position:0% +and what what I'm going to be teaching + + + align:start position:0% +and what what I'm going to be teaching +first of all quick question how many + + align:start position:0% +first of all quick question how many + + + align:start position:0% +first of all quick question how many +students here are not MIT students but + + align:start position:0% +students here are not MIT students but + + + align:start position:0% +students here are not MIT students but +cross register students okay h a bunch + + align:start position:0% +cross register students okay h a bunch + + + align:start position:0% +cross register students okay h a bunch +so you guys have access so I hope I made + + align:start position:0% +so you guys have access so I hope I made + + + align:start position:0% +so you guys have access so I hope I made +the the website public it's on canvas uh + + align:start position:0% +the the website public it's on canvas uh + + + align:start position:0% +the the website public it's on canvas uh +but now I think it should be public so + + align:start position:0% +but now I think it should be public so + + + align:start position:0% +but now I think it should be public so +uh you know you should have access if + + align:start position:0% +uh you know you should have access if + + + align:start position:0% +uh you know you should have access if +anyone has problems with accessing the + + align:start position:0% +anyone has problems with accessing the + + + align:start position:0% +anyone has problems with accessing the +website just let me know I'll try to fix + + align:start position:0% +website just let me know I'll try to fix + + + align:start position:0% +website just let me know I'll try to fix +it um so this class is meeting once a + + align:start position:0% +it um so this class is meeting once a + + + align:start position:0% +it um so this class is meeting once a +week weekly from 1: to 4: p.m. uh in + + align:start position:0% +week weekly from 1: to 4: p.m. uh in + + + align:start position:0% +week weekly from 1: to 4: p.m. uh in +terms of expectations or what uh so you + + align:start position:0% +terms of expectations or what uh so you + + + align:start position:0% +terms of expectations or what uh so you +know the expectations that you'll enjoy + + align:start position:0% +know the expectations that you'll enjoy + + + align:start position:0% +know the expectations that you'll enjoy +it I hope you will I think it's really + + align:start position:0% +it I hope you will I think it's really + + + align:start position:0% +it I hope you will I think it's really +really beautiful material uh but beyond + + align:start position:0% +really beautiful material uh but beyond + + + align:start position:0% +really beautiful material uh but beyond +having fun uh I want to ask uh I have uh + + align:start position:0% +having fun uh I want to ask uh I have uh + + + align:start position:0% +having fun uh I want to ask uh I have uh +two uh kind of uh requirements from you + + align:start position:0% +two uh kind of uh requirements from you + + + align:start position:0% +two uh kind of uh requirements from you +guys so one I want to have scribe notes + + align:start position:0% +guys so one I want to have scribe notes + + + align:start position:0% +guys so one I want to have scribe notes +for the classes uh I I have written + + align:start position:0% +for the classes uh I I have written + + + align:start position:0% +for the classes uh I I have written +notes I can give it to you uh to help + + align:start position:0% +notes I can give it to you uh to help + + + align:start position:0% +notes I can give it to you uh to help +you out but uh so we have about actually + + align:start position:0% +you out but uh so we have about actually + + + align:start position:0% +you out but uh so we have about actually +we we have 11 classes total in in this + + align:start position:0% +we we have 11 classes total in in this + + + align:start position:0% +we we have 11 classes total in in this +class but uh we're going to have a bunch + + align:start position:0% +class but uh we're going to have a bunch + + + align:start position:0% +class but uh we're going to have a bunch +of uh like one one day we're going to + + align:start position:0% +of uh like one one day we're going to + + + align:start position:0% +of uh like one one day we're going to +have a guest lecture uh by odv who's in + + align:start position:0% +have a guest lecture uh by odv who's in + + + align:start position:0% +have a guest lecture uh by odv who's in +he has a beautiful result he's going to + + align:start position:0% +he has a beautiful result he's going to + + + align:start position:0% +he has a beautiful result he's going to +come here uh on October 6 and presented + + align:start position:0% +come here uh on October 6 and presented + + + align:start position:0% +come here uh on October 6 and presented +to us so uh we won't H that won't need + + align:start position:0% +to us so uh we won't H that won't need + + + align:start position:0% +to us so uh we won't H that won't need +to be described and then there one day + + align:start position:0% +to be described and then there one day + + + align:start position:0% +to be described and then there one day +there's a crypto day which also won't + + align:start position:0% +there's a crypto day which also won't + + + align:start position:0% +there's a crypto day which also won't +need to be described well uh there's + + align:start position:0% + + + + align:start position:0% + +more anybody wants to + + align:start position:0% +more anybody wants to + + + align:start position:0% +more anybody wants to +sit uh but for the rest we'll need + + align:start position:0% +sit uh but for the rest we'll need + + + align:start position:0% +sit uh but for the rest we'll need +scribe notes I'm happy if you want to do + + align:start position:0% +scribe notes I'm happy if you want to do + + + align:start position:0% +scribe notes I'm happy if you want to do +it in pairs uh to describe unless will + + align:start position:0% +it in pairs uh to describe unless will + + + align:start position:0% +it in pairs uh to describe unless will +run out of people and then we'll need to + + align:start position:0% +run out of people and then we'll need to + + + align:start position:0% +run out of people and then we'll need to +keep it for one uh so that's one + + align:start position:0% +keep it for one uh so that's one + + + align:start position:0% +keep it for one uh so that's one +requirement and then I was told that I + + align:start position:0% +requirement and then I was told that I + + + align:start position:0% +requirement and then I was told that I +need to do something more you know + + align:start position:0% +need to do something more you know + + + align:start position:0% +need to do something more you know +that's not enough so we'll do a p set + + align:start position:0% +that's not enough so we'll do a p set + + + align:start position:0% +that's not enough so we'll do a p set +sometime in the middle of the course + + align:start position:0% +sometime in the middle of the course + + + align:start position:0% +sometime in the middle of the course +okay uh it won't be anything too + + align:start position:0% +okay uh it won't be anything too + + + align:start position:0% +okay uh it won't be anything too +difficult it's mainly to make sure + + align:start position:0% +difficult it's mainly to make sure + + + align:start position:0% +difficult it's mainly to make sure +you're on board uh but I really do + + align:start position:0% +you're on board uh but I really do + + + align:start position:0% +you're on board uh but I really do +recommend that before class every time + + align:start position:0% +recommend that before class every time + + + align:start position:0% +recommend that before class every time +before so here's a real homework okay uh + + align:start position:0% +before so here's a real homework okay uh + + + align:start position:0% +before so here's a real homework okay uh +every time before you come to class in + + align:start position:0% +every time before you come to class in + + + align:start position:0% +every time before you come to class in +the website there's reading I really + + align:start position:0% +the website there's reading I really + + + align:start position:0% +the website there's reading I really +recommend you look at the reading and + + align:start position:0% +recommend you look at the reading and + + + align:start position:0% +recommend you look at the reading and +try to read I so there's beautiful uh + + align:start position:0% +try to read I so there's beautiful uh + + + align:start position:0% +try to read I so there's beautiful uh +survey by Justin Taylor uh there's a + + align:start position:0% +survey by Justin Taylor uh there's a + + + align:start position:0% +survey by Justin Taylor uh there's a +link uh on the website uh the survey is + + align:start position:0% +link uh on the website uh the survey is + + + align:start position:0% +link uh on the website uh the survey is +on proof system it's more of kind of the + + align:start position:0% +on proof system it's more of kind of the + + + align:start position:0% +on proof system it's more of kind of the +applied side of proof system this is a + + align:start position:0% +applied side of proof system this is a + + + align:start position:0% +applied side of proof system this is a +more Theory class but he does have + + align:start position:0% +more Theory class but he does have + + + align:start position:0% +more Theory class but he does have +really beautifully written sections that + + align:start position:0% +really beautifully written sections that + + + align:start position:0% +really beautifully written sections that +are very theoretical that I'm going to + + align:start position:0% +are very theoretical that I'm going to + + + align:start position:0% +are very theoretical that I'm going to +link to uh so I recommend or I you can + + align:start position:0% +link to uh so I recommend or I you can + + + align:start position:0% +link to uh so I recommend or I you can +think of it as informal homework before + + align:start position:0% +think of it as informal homework before + + + align:start position:0% +think of it as informal homework before +class to do the reading I think it will + + align:start position:0% +class to do the reading I think it will + + + align:start position:0% +class to do the reading I think it will +be very helpful to uh for understanding + + align:start position:0% +be very helpful to uh for understanding + + + align:start position:0% +be very helpful to uh for understanding +this class and also after the you know + + align:start position:0% +this class and also after the you know + + + align:start position:0% +this class and also after the you know +the lecture to look at the reading and I + + align:start position:0% +the lecture to look at the reading and I + + + align:start position:0% +the lecture to look at the reading and I +think it'll be very very + + align:start position:0% +think it'll be very very + + + align:start position:0% +think it'll be very very +helpful okay so uh any questions about + + align:start position:0% +helpful okay so uh any questions about + + + align:start position:0% +helpful okay so uh any questions about +bureaucracy + + align:start position:0% +bureaucracy + + + align:start position:0% +bureaucracy +stuff okay so let me tell you a little + + align:start position:0% +stuff okay so let me tell you a little + + + align:start position:0% +stuff okay so let me tell you a little +bit more about about what the class is + + align:start position:0% +bit more about about what the class is + + + align:start position:0% +bit more about about what the class is +actually about so you know proofs is + + align:start position:0% +actually about so you know proofs is + + + align:start position:0% +actually about so you know proofs is +something that has been studied in + + align:start position:0% +something that has been studied in + + + align:start position:0% +something that has been studied in +mathematics for thousands of years uh + + align:start position:0% +mathematics for thousands of years uh + + + align:start position:0% +mathematics for thousands of years uh +and usually when people think about what + + align:start position:0% +and usually when people think about what + + + align:start position:0% +and usually when people think about what +a proof is uh you know a proof you write + + align:start position:0% +a proof is uh you know a proof you write + + + align:start position:0% +a proof is uh you know a proof you write +kind of line by line and you can verify + + align:start position:0% +kind of line by line and you can verify + + + align:start position:0% +kind of line by line and you can verify +it kind of line by line to make sure the + + align:start position:0% +it kind of line by line to make sure the + + + align:start position:0% +it kind of line by line to make sure the +proof is correct that's how you know + + align:start position:0% +proof is correct that's how you know + + + align:start position:0% +proof is correct that's how you know +most people think of what a proof is + + align:start position:0% +most people think of what a proof is + + + align:start position:0% +most people think of what a proof is +okay starting from the mid 80s in + + align:start position:0% +okay starting from the mid 80s in + + + align:start position:0% +okay starting from the mid 80s in +computer science and particular Le in + + align:start position:0% +computer science and particular Le in + + + align:start position:0% +computer science and particular Le in +cryptography the way we thought about + + align:start position:0% +cryptography the way we thought about + + + align:start position:0% +cryptography the way we thought about +proofs changed started changing this is + + align:start position:0% +proofs changed started changing this is + + + align:start position:0% +proofs changed started changing this is +uh came uh about because of the idea of + + align:start position:0% +uh came uh about because of the idea of + + + align:start position:0% +uh came uh about because of the idea of +zero knowledge proof so there was a hope + + align:start position:0% +zero knowledge proof so there was a hope + + + align:start position:0% +zero knowledge proof so there was a hope +to kind of construct proofs that reveal + + align:start position:0% +to kind of construct proofs that reveal + + + align:start position:0% +to kind of construct proofs that reveal +no information about why the claim is + + align:start position:0% +no information about why the claim is + + + align:start position:0% +no information about why the claim is +true and uh in around 85 uh godas M and + + align:start position:0% +true and uh in around 85 uh godas M and + + + align:start position:0% +true and uh in around 85 uh godas M and +roov kind of constructed the first zero + + align:start position:0% +roov kind of constructed the first zero + + + align:start position:0% +roov kind of constructed the first zero +knowledge proof by the way this class is + + align:start position:0% +knowledge proof by the way this class is + + + align:start position:0% +knowledge proof by the way this class is +not about zero knowledge actually it's + + align:start position:0% +not about zero knowledge actually it's + + + align:start position:0% +not about zero knowledge actually it's +not about crypto per se it's just about + + align:start position:0% +not about crypto per se it's just about + + + align:start position:0% +not about crypto per se it's just about +kind of coming up with new proof systems + + align:start position:0% +kind of coming up with new proof systems + + + align:start position:0% +kind of coming up with new proof systems +you have a + + align:start position:0% +you have a + + + align:start position:0% +you have a +question um but they constructed they + + align:start position:0% +question um but they constructed they + + + align:start position:0% +question um but they constructed they +want to construct these proofs that + + align:start position:0% +want to construct these proofs that + + + align:start position:0% +want to construct these proofs that +reveal no information and to do that + + align:start position:0% +reveal no information and to do that + + + align:start position:0% +reveal no information and to do that +they needed to change the model turns + + align:start position:0% +they needed to change the model turns + + + align:start position:0% +they needed to change the model turns +out they could not do it using kind of + + align:start position:0% +out they could not do it using kind of + + + align:start position:0% +out they could not do it using kind of +what we think of a classical proof and + + align:start position:0% +what we think of a classical proof and + + + align:start position:0% +what we think of a classical proof and +the way they changed the model is by + + align:start position:0% +the way they changed the model is by + + + align:start position:0% +the way they changed the model is by +defining a new uh proof system a new + + align:start position:0% +defining a new uh proof system a new + + + align:start position:0% +defining a new uh proof system a new +model uh which is called interactive + + align:start position:0% +model uh which is called interactive + + + align:start position:0% +model uh which is called interactive +proofs we're going to talk about this + + align:start position:0% +proofs we're going to talk about this + + + align:start position:0% +proofs we're going to talk about this +today okay but they Define this notion + + align:start position:0% +today okay but they Define this notion + + + align:start position:0% +today okay but they Define this notion +of interactive proof so the we're going + + align:start position:0% +of interactive proof so the we're going + + + align:start position:0% +of interactive proof so the we're going +to start this course by talking about + + align:start position:0% +to start this course by talking about + + + align:start position:0% +to start this course by talking about +what interactive proofs are okay uh and + + align:start position:0% +what interactive proofs are okay uh and + + + align:start position:0% +what interactive proofs are okay uh and +we're going to construct interactive + + align:start position:0% +we're going to construct interactive + + + align:start position:0% +we're going to construct interactive +proofs in the 80s and 90s when people + + align:start position:0% +proofs in the 80s and 90s when people + + + align:start position:0% +proofs in the 80s and 90s when people +thought about interactive proofs usually + + align:start position:0% +thought about interactive proofs usually + + + align:start position:0% +thought about interactive proofs usually +the model is we think of the verifier as + + align:start position:0% +the model is we think of the verifier as + + + align:start position:0% +the model is we think of the verifier as +being efficient for us efficient means + + align:start position:0% +being efficient for us efficient means + + + align:start position:0% +being efficient for us efficient means +polinomial time okay but of course uh + + align:start position:0% +polinomial time okay but of course uh + + + align:start position:0% +polinomial time okay but of course uh +you know in practice it has more + + align:start position:0% +you know in practice it has more + + + align:start position:0% +you know in practice it has more +specific meaning but for now think of + + align:start position:0% +specific meaning but for now think of + + + align:start position:0% +specific meaning but for now think of +efficient as being pomal time and the + + align:start position:0% +efficient as being pomal time and the + + + align:start position:0% +efficient as being pomal time and the +verifier can be all powerful so the the + + align:start position:0% +verifier can be all powerful so the the + + + align:start position:0% +verifier can be all powerful so the the +time complexity of the prover was not + + align:start position:0% +time complexity of the prover was not + + + align:start position:0% +time complexity of the prover was not +even a consideration actually they + + align:start position:0% +even a consideration actually they + + + align:start position:0% +even a consideration actually they +called the prover Merlin like he's a + + align:start position:0% +called the prover Merlin like he's a + + + align:start position:0% +called the prover Merlin like he's a +wizard can do whatever the hell he wants + + align:start position:0% +wizard can do whatever the hell he wants + + + align:start position:0% +wizard can do whatever the hell he wants +like in infinite + + align:start position:0% +like in infinite + + + align:start position:0% +like in infinite +power what we're going to talk about + + align:start position:0% +power what we're going to talk about + + + align:start position:0% +power what we're going to talk about +about after introducing this model and + + align:start position:0% +about after introducing this model and + + + align:start position:0% +about after introducing this model and +giving some protocols we're going to + + align:start position:0% +giving some protocols we're going to + + + align:start position:0% +giving some protocols we're going to +talk about the model of doubly efficient + + align:start position:0% +talk about the model of doubly efficient + + + align:start position:0% +talk about the model of doubly efficient +interactive proofs and here what we we + + align:start position:0% +interactive proofs and here what we we + + + align:start position:0% +interactive proofs and here what we we +say no the appr is not all powerful we + + align:start position:0% +say no the appr is not all powerful we + + + align:start position:0% +say no the appr is not all powerful we +don't have all powerful machines in the + + align:start position:0% +don't have all powerful machines in the + + + align:start position:0% +don't have all powerful machines in the +world every machine is bounded so what + + align:start position:0% +world every machine is bounded so what + + + align:start position:0% +world every machine is bounded so what +we want yes the verifier should be very + + align:start position:0% +we want yes the verifier should be very + + + align:start position:0% +we want yes the verifier should be very +efficient but the Prov should not be all + + align:start position:0% +efficient but the Prov should not be all + + + align:start position:0% +efficient but the Prov should not be all +powerful either so we care about the + + align:start position:0% +powerful either so we care about the + + + align:start position:0% +powerful either so we care about the +Prov running time too that's what called + + align:start position:0% +Prov running time too that's what called + + + align:start position:0% +Prov running time too that's what called +double efficient interactive proofs + + align:start position:0% +double efficient interactive proofs + + + align:start position:0% +double efficient interactive proofs +we're going to construct double + + align:start position:0% +we're going to construct double + + + align:start position:0% +we're going to construct double +efficient interactive proof uh we're + + align:start position:0% +efficient interactive proof uh we're + + + align:start position:0% +efficient interactive proof uh we're +going to show the GK protocol specific + + align:start position:0% +going to show the GK protocol specific + + + align:start position:0% +going to show the GK protocol specific +protocol and then we're going to show + + align:start position:0% +protocol and then we're going to show + + + align:start position:0% +protocol and then we're going to show +application of this protocol and we're + + align:start position:0% +application of this protocol and we're + + + align:start position:0% +application of this protocol and we're +going to see application to really nice + + align:start position:0% +going to see application to really nice + + + align:start position:0% +going to see application to really nice +kind of models such that PCP which is + + align:start position:0% +kind of models such that PCP which is + + + align:start position:0% +kind of models such that PCP which is +probabilistically checkable proofs nip + + align:start position:0% +probabilistically checkable proofs nip + + + align:start position:0% +probabilistically checkable proofs nip +multi prooof interactive proofs and + + align:start position:0% +multi prooof interactive proofs and + + + align:start position:0% +multi prooof interactive proofs and +particular we're going to show how to + + align:start position:0% +particular we're going to show how to + + + align:start position:0% +particular we're going to show how to +use this to get a a kind of we proove a + + align:start position:0% +use this to get a a kind of we proove a + + + align:start position:0% +use this to get a a kind of we proove a +celebrated result which is the IP equals + + align:start position:0% +celebrated result which is the IP equals + + + align:start position:0% +celebrated result which is the IP equals +ppace theorem of Shamir okay so this if + + align:start position:0% +ppace theorem of Shamir okay so this if + + + align:start position:0% +ppace theorem of Shamir okay so this if +you don't know any of these buzzwords + + align:start position:0% +you don't know any of these buzzwords + + + align:start position:0% +you don't know any of these buzzwords +I'll explain everything this is I'm just + + align:start position:0% +I'll explain everything this is I'm just + + + align:start position:0% +I'll explain everything this is I'm just +kind of doing a very quick overview for + + align:start position:0% +kind of doing a very quick overview for + + + align:start position:0% +kind of doing a very quick overview for +those who kind of heard these buzzwords + + align:start position:0% +those who kind of heard these buzzwords + + + align:start position:0% +those who kind of heard these buzzwords +a little bit and so you'll know what to + + align:start position:0% +a little bit and so you'll know what to + + + align:start position:0% +a little bit and so you'll know what to +expect okay so up to here no crypto at + + align:start position:0% +expect okay so up to here no crypto at + + + align:start position:0% +expect okay so up to here no crypto at +all this is not at all about crypto it's + + align:start position:0% +all this is not at all about crypto it's + + + align:start position:0% +all this is not at all about crypto it's +just about proof systems then we're + + align:start position:0% +just about proof systems then we're + + + align:start position:0% +just about proof systems then we're +going to show how to use cryptography to + + align:start position:0% +going to show how to use cryptography to + + + align:start position:0% +going to show how to use cryptography to +get our proofs more succinct okay and + + align:start position:0% +get our proofs more succinct okay and + + + align:start position:0% +get our proofs more succinct okay and +then we're going to kind of uh leave the + + align:start position:0% +then we're going to kind of uh leave the + + + align:start position:0% +then we're going to kind of uh leave the +idea the stand the classical idea of a + + align:start position:0% +idea the stand the classical idea of a + + + align:start position:0% +idea the stand the classical idea of a +proof that if the theorem is false there + + align:start position:0% +proof that if the theorem is false there + + + align:start position:0% +proof that if the theorem is false there +you can't cheat it's possible to cheat + + align:start position:0% +you can't cheat it's possible to cheat + + + align:start position:0% +you can't cheat it's possible to cheat +like there's no fake proof there's no + + align:start position:0% +like there's no fake proof there's no + + + align:start position:0% +like there's no fake proof there's no +false proof okay every there's no if the + + align:start position:0% +false proof okay every there's no if the + + + align:start position:0% +false proof okay every there's no if the +theorem is incorrect there's no proof + + align:start position:0% +theorem is incorrect there's no proof + + + align:start position:0% +theorem is incorrect there's no proof +period we're going to use crypto to say + + align:start position:0% +period we're going to use crypto to say + + + align:start position:0% +period we're going to use crypto to say +ah maybe they're false proof but they're + + align:start position:0% +ah maybe they're false proof but they're + + + align:start position:0% +ah maybe they're false proof but they're +very hard to find so the only way you + + align:start position:0% +very hard to find so the only way you + + + align:start position:0% +very hard to find so the only way you +can find a convincing proof to a false + + align:start position:0% +can find a convincing proof to a false + + + align:start position:0% +can find a convincing proof to a false +statement is by breaking kind of a hard + + align:start position:0% +statement is by breaking kind of a hard + + + align:start position:0% +statement is by breaking kind of a hard +uh cryptographic problem you can Factor + + align:start position:0% +uh cryptographic problem you can Factor + + + align:start position:0% +uh cryptographic problem you can Factor +large numbers you can break latus + + align:start position:0% +large numbers you can break latus + + + align:start position:0% +large numbers you can break latus +assumptions and so on okay so we're + + align:start position:0% +assumptions and so on okay so we're + + + align:start position:0% +assumptions and so on okay so we're +going to use a cryptography to make our + + align:start position:0% +going to use a cryptography to make our + + + align:start position:0% +going to use a cryptography to make our +proofs more succinct but then what what + + align:start position:0% +proofs more succinct but then what what + + + align:start position:0% +proofs more succinct but then what what +going on here is are proofs who can make + + align:start position:0% +going on here is are proofs who can make + + + align:start position:0% +going on here is are proofs who can make +them succinct but they're still + + align:start position:0% +them succinct but they're still + + + align:start position:0% +them succinct but they're still +interactive and then we're going to show + + align:start position:0% +interactive and then we're going to show + + + align:start position:0% +interactive and then we're going to show +how to use this beautiful F Cham + + align:start position:0% +how to use this beautiful F Cham + + + align:start position:0% +how to use this beautiful F Cham +Paradigm which is a paradigm for + + align:start position:0% +Paradigm which is a paradigm for + + + align:start position:0% +Paradigm which is a paradigm for +reducing interaction and we're going to + + align:start position:0% +reducing interaction and we're going to + + + align:start position:0% +reducing interaction and we're going to +kind of study the security of this + + align:start position:0% +kind of study the security of this + + + align:start position:0% +kind of study the security of this +Paradigm and show how to make this + + align:start position:0% +Paradigm and show how to make this + + + align:start position:0% +Paradigm and show how to make this +Paradigm secure okay so these are kind + + align:start position:0% +Paradigm secure okay so these are kind + + + align:start position:0% +Paradigm secure okay so these are kind +of results that have happened very + + align:start position:0% +of results that have happened very + + + align:start position:0% +of results that have happened very +recently actually one of the students + + align:start position:0% +recently actually one of the students + + + align:start position:0% +recently actually one of the students +here Alex Lombardi at MIT uh was V not + + align:start position:0% +here Alex Lombardi at MIT uh was V not + + + align:start position:0% +here Alex Lombardi at MIT uh was V not +student was uh one of the people who + + align:start position:0% +student was uh one of the people who + + + align:start position:0% +student was uh one of the people who +came show kind of the security of this + + align:start position:0% +came show kind of the security of this + + + align:start position:0% +came show kind of the security of this +Paradigm so we're going show it we're + + align:start position:0% +Paradigm so we're going show it we're + + + align:start position:0% +Paradigm so we're going show it we're +going to use it then to show how to get + + align:start position:0% +going to use it then to show how to get + + + align:start position:0% +going to use it then to show how to get +our doubly efficient interactive proof + + align:start position:0% +our doubly efficient interactive proof + + + align:start position:0% +our doubly efficient interactive proof +how to make it non interactive anymore + + align:start position:0% +how to make it non interactive anymore + + + align:start position:0% +how to make it non interactive anymore +so make it completely + + align:start position:0% +so make it completely + + + align:start position:0% +so make it completely +non-interactive we're going to also show + + align:start position:0% +non-interactive we're going to also show + + + align:start position:0% +non-interactive we're going to also show +to use this fimir Paradigm to do kind of + + align:start position:0% +to use this fimir Paradigm to do kind of + + + align:start position:0% +to use this fimir Paradigm to do kind of +batch proofs uh non-interactively in + + align:start position:0% +batch proofs uh non-interactively in + + + align:start position:0% +batch proofs uh non-interactively in +very succinct way so taking a bunch of + + align:start position:0% +very succinct way so taking a bunch of + + + align:start position:0% +very succinct way so taking a bunch of +claims and kind of giving one uh short + + align:start position:0% +claims and kind of giving one uh short + + + align:start position:0% +claims and kind of giving one uh short +proof from them and finally we're going + + align:start position:0% +proof from them and finally we're going + + + align:start position:0% +proof from them and finally we're going +to show how to use that to go all the + + align:start position:0% +to show how to use that to go all the + + + align:start position:0% +to show how to use that to go all the +way to what's called a snar which is a + + align:start position:0% +way to what's called a snar which is a + + + align:start position:0% +way to what's called a snar which is a +succinct non-interactive argument + + align:start position:0% +succinct non-interactive argument + + + align:start position:0% +succinct non-interactive argument +argument is just another word for a + + align:start position:0% +argument is just another word for a + + + align:start position:0% +argument is just another word for a +computationally soundproof so this is + + align:start position:0% +computationally soundproof so this is + + + align:start position:0% +computationally soundproof so this is +kind of very very high level of what you + + align:start position:0% +kind of very very high level of what you + + + align:start position:0% +kind of very very high level of what you +should expect uh uh to learn in this + + align:start position:0% +should expect uh uh to learn in this + + + align:start position:0% +should expect uh uh to learn in this +class if you didn't understand a word + + align:start position:0% +class if you didn't understand a word + + + align:start position:0% +class if you didn't understand a word +what I said then this is what the hope + + align:start position:0% +what I said then this is what the hope + + + align:start position:0% +what I said then this is what the hope +the goal is that you will understand + + align:start position:0% +the goal is that you will understand + + + align:start position:0% +the goal is that you will understand +this by the end of this + + align:start position:0% +this by the end of this + + + align:start position:0% +this by the end of this +class okay uh questions before I start + + align:start position:0% +class okay uh questions before I start + + + align:start position:0% +class okay uh questions before I start +okay I need a volunteer to scribe for + + align:start position:0% +okay I need a volunteer to scribe for + + + align:start position:0% +okay I need a volunteer to scribe for +today oh fantastic thanks okay so with + + align:start position:0% +today oh fantastic thanks okay so with + + + align:start position:0% +today oh fantastic thanks okay so with +that let let's start so let's start with + + align:start position:0% +that let let's start so let's start with + + + align:start position:0% +that let let's start so let's start with +the notion of of interactive proofs and + + align:start position:0% +the notion of of interactive proofs and + + + align:start position:0% +the notion of of interactive proofs and +before I go to interactive proofs let me + + align:start position:0% +before I go to interactive proofs let me + + + align:start position:0% +before I go to interactive proofs let me +just you know even before intive proofs + + align:start position:0% +just you know even before intive proofs + + + align:start position:0% +just you know even before intive proofs +let's look at the class NP + + align:start position:0% +let's look at the class NP + + + align:start position:0% +let's look at the class NP +non-deterministic pomal time even this + + align:start position:0% +non-deterministic pomal time even this + + + align:start position:0% +non-deterministic pomal time even this +class is about proof system right so + + align:start position:0% +class is about proof system right so + + + align:start position:0% +class is about proof system right so +what is this this class is trying + + align:start position:0% +what is this this class is trying + + + align:start position:0% +what is this this class is trying +to by the way there's another chair here + + align:start position:0% +to by the way there's another chair here + + + align:start position:0% +to by the way there's another chair here +for those who don't have a chair there's + + align:start position:0% +for those who don't have a chair there's + + + align:start position:0% +for those who don't have a chair there's +one right here + + align:start position:0% + + + + align:start position:0% + +great great so even before we go to the + + align:start position:0% +great great so even before we go to the + + + align:start position:0% +great great so even before we go to the +interactive setting let's even think of + + align:start position:0% +interactive setting let's even think of + + + align:start position:0% +interactive setting let's even think of +the class NP what is the class NP if you + + align:start position:0% +the class NP what is the class NP if you + + + align:start position:0% +the class NP what is the class NP if you +think about it it's all the + + align:start position:0% +think about it it's all the + + + align:start position:0% +think about it it's all the +languages that have a proof that's the + + align:start position:0% +languages that have a proof that's the + + + align:start position:0% +languages that have a proof that's the +witness that can be verified by + + align:start position:0% +witness that can be verified by + + + align:start position:0% +witness that can be verified by +polinomial time okay so we want to think + + align:start position:0% +polinomial time okay so we want to think + + + align:start position:0% +polinomial time okay so we want to think +with the here's the the framework for + + align:start position:0% +with the here's the the framework for + + + align:start position:0% +with the here's the the framework for +this class is the following we want to + + align:start position:0% +this class is the following we want to + + + align:start position:0% +this class is the following we want to +ask I we have the verifiers are pomal + + align:start position:0% +ask I we have the verifiers are pomal + + + align:start position:0% +ask I we have the verifiers are pomal +time or even like there there you know + + align:start position:0% +time or even like there there you know + + + align:start position:0% +time or even like there there you know +they're very efficient what can you + + align:start position:0% +they're very efficient what can you + + + align:start position:0% +they're very efficient what can you +prove to these + + align:start position:0% +prove to these + + + align:start position:0% +prove to these +verifiers okay so that's exactly what NP + + align:start position:0% +verifiers okay so that's exactly what NP + + + align:start position:0% +verifiers okay so that's exactly what NP +captures NP is all the + + align:start position:0% +captures NP is all the + + + align:start position:0% +captures NP is all the +languages that you can prove membership + + align:start position:0% +languages that you can prove membership + + + align:start position:0% +languages that you can prove membership +in the language to pomal time + + align:start position:0% +in the language to pomal time + + + align:start position:0% +in the language to pomal time +verifier okay so NP is exactly the + + align:start position:0% +verifier okay so NP is exactly the + + + align:start position:0% +verifier okay so NP is exactly the +set of + + align:start position:0% + + + + align:start position:0% + +languages m + + align:start position:0% + + + + align:start position:0% + +ship can be + + align:start position:0% + + + + align:start position:0% + +proved in poly time so for or can + + align:start position:0% +proved in poly time so for or can + + + align:start position:0% +proved in poly time so for or can +prove or can prove to a PO time maybe I + + align:start position:0% +prove or can prove to a PO time maybe I + + + align:start position:0% +prove or can prove to a PO time maybe I +should say can proved + + align:start position:0% +should say can proved + + + align:start position:0% +should say can proved +to a polinomial Time + + align:start position:0% + + + + align:start position:0% + +verifier so uh poal time verifier can + + align:start position:0% +verifier so uh poal time verifier can + + + align:start position:0% +verifier so uh poal time verifier can +verify membership in the language so far + + align:start position:0% +verify membership in the language so far + + + align:start position:0% +verify membership in the language so far +so good okay but NP is not that rich + + align:start position:0% +so good okay but NP is not that rich + + + align:start position:0% +so good okay but NP is not that rich +okay so we want more more than NP okay + + align:start position:0% +okay so we want more more than NP okay + + + align:start position:0% +okay so we want more more than NP okay +so let's so okay so one thing we can add + + align:start position:0% +so let's so okay so one thing we can add + + + align:start position:0% +so let's so okay so one thing we can add +so what is the class IP the first thing + + align:start position:0% +so what is the class IP the first thing + + + align:start position:0% +so what is the class IP the first thing +that so IP interactive proofs and two + + align:start position:0% + + + + align:start position:0% + +components so in NP the proof is + + align:start position:0% +components so in NP the proof is + + + align:start position:0% +components so in NP the proof is +classical it's the class of languages + + align:start position:0% +classical it's the class of languages + + + align:start position:0% +classical it's the class of languages +for which a membership can be proved + + align:start position:0% +for which a membership can be proved + + + align:start position:0% +for which a membership can be proved +using a classical + + align:start position:0% +using a classical + + + align:start position:0% +using a classical +proof okay like a proof that you know + + align:start position:0% +proof okay like a proof that you know + + + align:start position:0% +proof okay like a proof that you know +you can verify just like running a + + align:start position:0% +you can verify just like running a + + + align:start position:0% +you can verify just like running a +touring machine okay interactive proofs + + align:start position:0% +touring machine okay interactive proofs + + + align:start position:0% +touring machine okay interactive proofs +are different in two ways first of all + + align:start position:0% +are different in two ways first of all + + + align:start position:0% +are different in two ways first of all +we + + align:start position:0% +we + + + align:start position:0% +we +allow + + align:start position:0% +allow + + + align:start position:0% +allow +interaction between the prover and the + + align:start position:0% +interaction between the prover and the + + + align:start position:0% +interaction between the prover and the +verifier they can talk back and + + align:start position:0% +verifier they can talk back and + + + align:start position:0% +verifier they can talk back and +forth + + align:start position:0% +forth + + + align:start position:0% +forth +importantly we allow + + align:start position:0% + + + + align:start position:0% + +randomization now note what do I mean + + align:start position:0% +randomization now note what do I mean + + + align:start position:0% +randomization now note what do I mean +randomization the verifier can be + + align:start position:0% +randomization the verifier can be + + + align:start position:0% +randomization the verifier can be +randomized and there can be some chance + + align:start position:0% +randomized and there can be some chance + + + align:start position:0% +randomized and there can be some chance +that the theorem is uh false and he'll + + align:start position:0% +that the theorem is uh false and he'll + + + align:start position:0% +that the theorem is uh false and he'll +accept but that's very very small okay + + align:start position:0% +accept but that's very very small okay + + + align:start position:0% +accept but that's very very small okay +we can make it kind of if the + + align:start position:0% +we can make it kind of if the + + + align:start position:0% +we can make it kind of if the +communication complexity is let's say n + + align:start position:0% +communication complexity is let's say n + + + align:start position:0% +communication complexity is let's say n +we can make you'll you'll accept the + + align:start position:0% +we can make you'll you'll accept the + + + align:start position:0% +we can make you'll you'll accept the +false statement probability something + + align:start position:0% +false statement probability something + + + align:start position:0% +false statement probability something +like 2 Theus n so we can make it very + + align:start position:0% +like 2 Theus n so we can make it very + + + align:start position:0% +like 2 Theus n so we can make it very +very small but there is a nonzero chance + + align:start position:0% +very small but there is a nonzero chance + + + align:start position:0% +very small but there is a nonzero chance +that you'll accept false statement okay + + align:start position:0% +that you'll accept false statement okay + + + align:start position:0% +that you'll accept false statement okay +so in that sense we weakened the + + align:start position:0% +so in that sense we weakened the + + + align:start position:0% +so in that sense we weakened the +model now note if there's no + + align:start position:0% +model now note if there's no + + + align:start position:0% +model now note if there's no +randomization if we force the + + align:start position:0% +randomization if we force the + + + align:start position:0% +randomization if we force the +verifier to be deterministic if the + + align:start position:0% +verifier to be deterministic if the + + + align:start position:0% +verifier to be deterministic if the +interaction so again the interactive + + align:start position:0% +interaction so again the interactive + + + align:start position:0% +interaction so again the interactive +proof is a kind of + + align:start position:0% +proof is a kind of + + + align:start position:0% +proof is a kind of +interactive protocol between approver + + align:start position:0% +interactive protocol between approver + + + align:start position:0% +interactive protocol between approver +and verifier if the approver knew what + + align:start position:0% +and verifier if the approver knew what + + + align:start position:0% +and verifier if the approver knew what +the verifier is going to send if he was + + align:start position:0% +the verifier is going to send if he was + + + align:start position:0% +the verifier is going to send if he was +completely + + align:start position:0% +completely + + + align:start position:0% +completely +deterministic then the pro can just + + align:start position:0% +deterministic then the pro can just + + + align:start position:0% +deterministic then the pro can just +generate the entire transcript and give + + align:start position:0% +generate the entire transcript and give + + + align:start position:0% +generate the entire transcript and give +it as a proof so it will really be + + align:start position:0% +it as a proof so it will really be + + + align:start position:0% +it as a proof so it will really be +NP there's no point of this + + align:start position:0% +NP there's no point of this + + + align:start position:0% +NP there's no point of this +interaction so really the power of this + + align:start position:0% +interaction so really the power of this + + + align:start position:0% +interaction so really the power of this +IP comes from the fact that the verifier + + align:start position:0% +IP comes from the fact that the verifier + + + align:start position:0% +IP comes from the fact that the verifier +is interacted it comes from the fact + + align:start position:0% +is interacted it comes from the fact + + + align:start position:0% +is interacted it comes from the fact +that the verifier is interactive is is + + align:start position:0% +that the verifier is interactive is is + + + align:start position:0% +that the verifier is interactive is is +randomized sorry is randomized and the + + align:start position:0% +randomized sorry is randomized and the + + + align:start position:0% +randomized sorry is randomized and the +pro doesn't know what this Randomness is + + align:start position:0% +pro doesn't know what this Randomness is + + + align:start position:0% +pro doesn't know what this Randomness is +going to be so if I'm trying to prove to + + align:start position:0% +going to be so if I'm trying to prove to + + + align:start position:0% +going to be so if I'm trying to prove to +you a + + align:start position:0% +you a + + + align:start position:0% +you a +statement I send you my first message I + + align:start position:0% +statement I send you my first message I + + + align:start position:0% +statement I send you my first message I +don't know what question you're going to + + align:start position:0% +don't know what question you're going to + + + align:start position:0% +don't know what question you're going to +ask me you're going answer some random + + align:start position:0% +ask me you're going answer some random + + + align:start position:0% +ask me you're going answer some random +questions and I'll need to give an + + align:start position:0% +questions and I'll need to give an + + + align:start position:0% +questions and I'll need to give an +answer and then I don't know what the + + align:start position:0% +answer and then I don't know what the + + + align:start position:0% +answer and then I don't know what the +next question if I knew all your + + align:start position:0% +next question if I knew all your + + + align:start position:0% +next question if I knew all your +question in advance then there's no + + align:start position:0% +question in advance then there's no + + + align:start position:0% +question in advance then there's no +point it's like it loses the power okay + + align:start position:0% +point it's like it loses the power okay + + + align:start position:0% +point it's like it loses the power okay +so really the power comes from the fact + + align:start position:0% +so really the power comes from the fact + + + align:start position:0% +so really the power comes from the fact +that there's interraction in the PO + + align:start position:0% +that there's interraction in the PO + + + align:start position:0% +that there's interraction in the PO +cannot predict ahead of time what + + align:start position:0% +cannot predict ahead of time what + + + align:start position:0% +cannot predict ahead of time what +questions he's going to get from the + + align:start position:0% +questions he's going to get from the + + + align:start position:0% +questions he's going to get from the +verifier okay so any any + + align:start position:0% + + + + align:start position:0% + +questions Okay so + + align:start position:0% +questions Okay so + + + align:start position:0% +questions Okay so +I can I did Define this formul yet I'll + + align:start position:0% +I can I did Define this formul yet I'll + + + align:start position:0% +I can I did Define this formul yet I'll +Define it formally in a bit but I hope I + + align:start position:0% +Define it formally in a bit but I hope I + + + align:start position:0% +Define it formally in a bit but I hope I +convinced you that like without + + align:start position:0% +convinced you that like without + + + align:start position:0% +convinced you that like without +Randomness this model is really useless + + align:start position:0% +Randomness this model is really useless + + + align:start position:0% +Randomness this model is really useless +okay there's no point how about just how + + align:start position:0% +okay there's no point how about just how + + + align:start position:0% +okay there's no point how about just how +about without inaction let's say I had + + align:start position:0% +about without inaction let's say I had + + + align:start position:0% +about without inaction let's say I had +only + + align:start position:0% +only + + + align:start position:0% +only +Randomness do I get more and actually so + + align:start position:0% +Randomness do I get more and actually so + + + align:start position:0% +Randomness do I get more and actually so +what what if we allow only + + align:start position:0% +what what if we allow only + + + align:start position:0% +what what if we allow only +Randomness so + + align:start position:0% +Randomness so + + + align:start position:0% +Randomness so +proofs so let's talk about + + align:start position:0% +proofs so let's talk about + + + align:start position:0% +proofs so let's talk about +non-interactive proofs + + align:start position:0% + + + + align:start position:0% + +where the verifier V is + + align:start position:0% + + + + align:start position:0% + +randomized by the way I forgot to say + + align:start position:0% +randomized by the way I forgot to say + + + align:start position:0% +randomized by the way I forgot to say +please stop me at any point and ask me + + align:start position:0% +please stop me at any point and ask me + + + align:start position:0% +please stop me at any point and ask me +questions I like questions questions are + + align:start position:0% +questions I like questions questions are + + + align:start position:0% +questions I like questions questions are +good for me to kind of SL me down it + + align:start position:0% +good for me to kind of SL me down it + + + align:start position:0% +good for me to kind of SL me down it +gives you an opportunity to digest so + + align:start position:0% +gives you an opportunity to digest so + + + align:start position:0% +gives you an opportunity to digest so +it's a great thing so please just at any + + align:start position:0% +it's a great thing so please just at any + + + align:start position:0% +it's a great thing so please just at any +point stop me with questions + + align:start position:0% + + + + align:start position:0% + +questions okay so uh good so what what + + align:start position:0% +questions okay so uh good so what what + + + align:start position:0% +questions okay so uh good so what what +about if we so we said if we get rid of + + align:start position:0% +about if we so we said if we get rid of + + + align:start position:0% +about if we so we said if we get rid of +Randomness we get nothing what if we get + + align:start position:0% +Randomness we get nothing what if we get + + + align:start position:0% +Randomness we get nothing what if we get +rid of interaction and we just allow + + align:start position:0% +rid of interaction and we just allow + + + align:start position:0% +rid of interaction and we just allow +Randomness do we get more and actually + + align:start position:0% +Randomness do we get more and actually + + + align:start position:0% +Randomness do we get more and actually +we do get more okay and actually this + + align:start position:0% +we do get more okay and actually this + + + align:start position:0% +we do get more okay and actually this +complexity test is a name this is ma for + + align:start position:0% +complexity test is a name this is ma for + + + align:start position:0% +complexity test is a name this is ma for +Merlin Arthur Arthur is known as a + + align:start position:0% +Merlin Arthur Arthur is known as a + + + align:start position:0% +Merlin Arthur Arthur is known as a +verify Merin is known as aover so kind + + align:start position:0% +verify Merin is known as aover so kind + + + align:start position:0% +verify Merin is known as aover so kind +of the approver sends a message Arthur + + align:start position:0% +of the approver sends a message Arthur + + + align:start position:0% +of the approver sends a message Arthur +the verifier can kind of toss coins and + + align:start position:0% +the verifier can kind of toss coins and + + + align:start position:0% +the verifier can kind of toss coins and +based on that decide if to accept or not + + align:start position:0% +based on that decide if to accept or not + + + align:start position:0% +based on that decide if to accept or not +but anyway the non the non-interactive + + align:start position:0% +but anyway the non the non-interactive + + + align:start position:0% +but anyway the non the non-interactive +randomized version is uh believe to be I + + align:start position:0% +randomized version is uh believe to be I + + + align:start position:0% +randomized version is uh believe to be I +mean it may be more powerful than NP we + + align:start position:0% +mean it may be more powerful than NP we + + + align:start position:0% +mean it may be more powerful than NP we +actually don't know but it seems there's + + align:start position:0% +actually don't know but it seems there's + + + align:start position:0% +actually don't know but it seems there's +some more power and actually let me give + + align:start position:0% +some more power and actually let me give + + + align:start position:0% +some more power and actually let me give +you an example this is example that will + + align:start position:0% +you an example this is example that will + + + align:start position:0% +you an example this is example that will +kind of be useful for us later so it's + + align:start position:0% +kind of be useful for us later so it's + + + align:start position:0% +kind of be useful for us later so it's +not only an example but let me give you + + align:start position:0% +not only an example but let me give you + + + align:start position:0% +not only an example but let me give you +an example where kind of Randomness can + + align:start position:0% +an example where kind of Randomness can + + + align:start position:0% +an example where kind of Randomness can +be helpful for us okay so suppose you + + align:start position:0% +be helpful for us okay so suppose you + + + align:start position:0% +be helpful for us okay so suppose you +want to + + align:start position:0% +want to + + + align:start position:0% +want to +verify let's say you have two n byn + + align:start position:0% +verify let's say you have two n byn + + + align:start position:0% +verify let's say you have two n byn +matrices A and B these are n byn + + align:start position:0% + + + + align:start position:0% + +matrices let's say over Z1 or over a + + align:start position:0% +matrices let's say over Z1 or over a + + + align:start position:0% +matrices let's say over Z1 or over a +finite + + align:start position:0% + + + + align:start position:0% + +field and let's say you want to verify + + align:start position:0% +field and let's say you want to verify + + + align:start position:0% +field and let's say you want to verify +suppose you want to + + align:start position:0% +suppose you want to + + + align:start position:0% +suppose you want to +verify that some Matrix C is equal to a + + align:start position:0% +verify that some Matrix C is equal to a + + + align:start position:0% +verify that some Matrix C is equal to a +* + + align:start position:0% +* + + + align:start position:0% +* +B so you're also given let's say + + align:start position:0% +B so you're also given let's say + + + align:start position:0% +B so you're also given let's say +C you want to so you you need to verify + + align:start position:0% +C you want to so you you need to verify + + + align:start position:0% +C you want to so you you need to verify +task of matrix + + align:start position:0% +task of matrix + + + align:start position:0% +task of matrix +multiplication okay we can do it + + align:start position:0% +multiplication okay we can do it + + + align:start position:0% +multiplication okay we can do it +efficiently in general the best known + + align:start position:0% +efficiently in general the best known + + + align:start position:0% +efficiently in general the best known +algorithm is something like order uh o + + align:start position:0% +algorithm is something like order uh o + + + align:start position:0% +algorithm is something like order uh o +of n to the 2 3 6 maybe something like + + align:start position:0% +of n to the 2 3 6 maybe something like + + + align:start position:0% +of n to the 2 3 6 maybe something like +that that's the best known matrix + + align:start position:0% +that that's the best known matrix + + + align:start position:0% +that that's the best known matrix +multiplication + + align:start position:0% +multiplication + + + align:start position:0% +multiplication +algorithm why you looking me the number + + align:start position:0% +algorithm why you looking me the number + + + align:start position:0% +algorithm why you looking me the number +yeah close uh let but turns out that if + + align:start position:0% +yeah close uh let but turns out that if + + + align:start position:0% +yeah close uh let but turns out that if +using randomization + + align:start position:0% +using randomization + + + align:start position:0% +using randomization +you can do it more efficiently okay so + + align:start position:0% +you can do it more efficiently okay so + + + align:start position:0% +you can do it more efficiently okay so +let's show how you can verify that a + + align:start position:0% +let's show how you can verify that a + + + align:start position:0% +let's show how you can verify that a +matrix C is a product of two matrices A + + align:start position:0% +matrix C is a product of two matrices A + + + align:start position:0% +matrix C is a product of two matrices A +and B in time order and + + align:start position:0% +and B in time order and + + + align:start position:0% +and B in time order and +squared okay so kind of the best you can + + align:start position:0% +squared okay so kind of the best you can + + + align:start position:0% +squared okay so kind of the best you can +do because you need to read the the + + align:start position:0% +do because you need to read the the + + + align:start position:0% +do because you need to read the the +input okay so how will you do that + + align:start position:0% +input okay so how will you do that + + + align:start position:0% +input okay so how will you do that +here's the idea so here's a + + align:start position:0% + + + + align:start position:0% + +randomized algorithm for verifying this + + align:start position:0% + + + + align:start position:0% + +so let's assume that F first assume this + + align:start position:0% +so let's assume that F first assume this + + + align:start position:0% +so let's assume that F first assume this +is kind of without lots of + + align:start position:0% + + + + align:start position:0% + +generality that f is much bigger than + + align:start position:0% +generality that f is much bigger than + + + align:start position:0% +generality that f is much bigger than +n if not you can take kind of an + + align:start position:0% +n if not you can take kind of an + + + align:start position:0% +n if not you can take kind of an +extension field of that okay embedded in + + align:start position:0% +extension field of that okay embedded in + + + align:start position:0% +extension field of that okay embedded in +a much bigger field so just let's assume + + align:start position:0% +a much bigger field so just let's assume + + + align:start position:0% +a much bigger field so just let's assume +if those who are not kind of comfortable + + align:start position:0% +if those who are not kind of comfortable + + + align:start position:0% +if those who are not kind of comfortable +with extension field let's assume it's + + align:start position:0% +with extension field let's assume it's + + + align:start position:0% +with extension field let's assume it's +just much + + align:start position:0% +just much + + + align:start position:0% +just much +bigger okay then what do you do here's + + align:start position:0% +bigger okay then what do you do here's + + + align:start position:0% +bigger okay then what do you do here's +my algorithm what I'm going to do I'm + + align:start position:0% +my algorithm what I'm going to do I'm + + + align:start position:0% +my algorithm what I'm going to do I'm +going to choose a random element in the + + align:start position:0% + + + + align:start position:0% + +field I'm going to consider X which is + + align:start position:0% +field I'm going to consider X which is + + + align:start position:0% +field I'm going to consider X which is +just uh 1 r r 2 up to R to the N minus + + align:start position:0% +just uh 1 r r 2 up to R to the N minus + + + align:start position:0% +just uh 1 r r 2 up to R to the N minus +one okay so all the powers of R I chose + + align:start position:0% +one okay so all the powers of R I chose + + + align:start position:0% +one okay so all the powers of R I chose +a random R in the field I look at all + + align:start position:0% +a random R in the field I look at all + + + align:start position:0% +a random R in the field I look at all +the powers of + + align:start position:0% +the powers of + + + align:start position:0% +the powers of +R and then what do I + + align:start position:0% + + + + align:start position:0% + +do yeah + + align:start position:0% + + + + align:start position:0% + +exactly and then I'm going to + + align:start position:0% +exactly and then I'm going to + + + align:start position:0% +exactly and then I'm going to +check if C * X I guess + + align:start position:0% +check if C * X I guess + + + align:start position:0% +check if C * X I guess +transpose because I wrote it is equal to + + align:start position:0% +transpose because I wrote it is equal to + + + align:start position:0% +transpose because I wrote it is equal to +a b * + + align:start position:0% + + + + align:start position:0% + +X that's my + + align:start position:0% +X that's my + + + align:start position:0% +X that's my +algorithm okay so note + + align:start position:0% +algorithm okay so note + + + align:start position:0% +algorithm okay so note +uh yeah + + align:start position:0% +uh yeah + + + align:start position:0% +uh yeah +so so note this is just a vector and + + align:start position:0% +so so note this is just a vector and + + + align:start position:0% +so so note this is just a vector and +Vector times Matrix mult so to multiply + + align:start position:0% +Vector times Matrix mult so to multiply + + + align:start position:0% +Vector times Matrix mult so to multiply +a matrix by Vector is time n squ as + + align:start position:0% +a matrix by Vector is time n squ as + + + align:start position:0% +a matrix by Vector is time n squ as +opposed to you know the N to the 23 six + + align:start position:0% +opposed to you know the N to the 23 six + + + align:start position:0% +opposed to you know the N to the 23 six +so this is more efficient why is it okay + + align:start position:0% +so this is more efficient why is it okay + + + align:start position:0% +so this is more efficient why is it okay +why why so of course it's complete if + + align:start position:0% +why why so of course it's complete if + + + align:start position:0% +why why so of course it's complete if +these are equal I'm going to accept Okay + + align:start position:0% +these are equal I'm going to accept Okay + + + align:start position:0% +these are equal I'm going to accept Okay +but if they're not + + align:start position:0% +but if they're not + + + align:start position:0% +but if they're not +equal so so why why is it uh sound so + + align:start position:0% +equal so so why why is it uh sound so + + + align:start position:0% +equal so so why why is it uh sound so +maybe you can convince me let's say + + align:start position:0% +maybe you can convince me let's say + + + align:start position:0% +maybe you can convince me let's say +they're not equal maybe you can still + + align:start position:0% +they're not equal maybe you can still + + + align:start position:0% +they're not equal maybe you can still +convince me that they're equal that + + align:start position:0% +convince me that they're equal that + + + align:start position:0% +convince me that they're equal that +would be a problem + + align:start position:0% + + + + align:start position:0% + +so let + + align:start position:0% + + + + align:start position:0% + +yeah the size of the field iser than n + + align:start position:0% +yeah the size of the field iser than n + + + align:start position:0% +yeah the size of the field iser than n +it's that like fantastic fantastic so + + align:start position:0% +it's that like fantastic fantastic so + + + align:start position:0% +it's that like fantastic fantastic so +here's let me just repeat what you said + + align:start position:0% +here's let me just repeat what you said + + + align:start position:0% +here's let me just repeat what you said +a b bit more formly so suppose they're + + align:start position:0% +a b bit more formly so suppose they're + + + align:start position:0% +a b bit more formly so suppose they're +not equal there's one row that they're + + align:start position:0% +not equal there's one row that they're + + + align:start position:0% +not equal there's one row that they're +not equal on right let's focus on that + + align:start position:0% +not equal on right let's focus on that + + + align:start position:0% +not equal on right let's focus on that +row so you can think of what when I do c + + align:start position:0% +row so you can think of what when I do c + + + align:start position:0% +row so you can think of what when I do c +* X let's let's say C1 like the first + + align:start position:0% +* X let's let's say C1 like the first + + + align:start position:0% +* X let's let's say C1 like the first +row of C when I do c * + + align:start position:0% +row of C when I do c * + + + align:start position:0% +row of C when I do c * +X this is you can think of this as I + + align:start position:0% +X this is you can think of this as I + + + align:start position:0% +X this is you can think of this as I +take I look at this the row as a polom + + align:start position:0% +take I look at this the row as a polom + + + align:start position:0% +take I look at this the row as a polom +so if you look at the first row maybe + + align:start position:0% +so if you look at the first row maybe + + + align:start position:0% +so if you look at the first row maybe +I'll write it as C11 up to or C10 up to + + align:start position:0% +I'll write it as C11 up to or C10 up to + + + align:start position:0% +I'll write it as C11 up to or C10 up to +C1 n minus one okay let's look at this n + + align:start position:0% +C1 n minus one okay let's look at this n + + + align:start position:0% +C1 n minus one okay let's look at this n +row when I multiply by X which is one r + + align:start position:0% +row when I multiply by X which is one r + + + align:start position:0% +row when I multiply by X which is one r +r squ this is nothing but some C 1 i x + + align:start position:0% +r squ this is nothing but some C 1 i x + + + align:start position:0% +r squ this is nothing but some C 1 i x +to the I or sorry R to the + + align:start position:0% + + + + align:start position:0% + +I so now what do I check so now you know + + align:start position:0% +I so now what do I check so now you know + + + align:start position:0% +I so now what do I check so now you know +if this row let's say it is different + + align:start position:0% +if this row let's say it is different + + + align:start position:0% +if this row let's say it is different +than the row + + align:start position:0% +than the row + + + align:start position:0% +than the row +here then I have two different + + align:start position:0% +here then I have two different + + + align:start position:0% +here then I have two different +pols right so if I write if I write the + + align:start position:0% +pols right so if I write if I write the + + + align:start position:0% +pols right so if I write if I write the +row there let's say as I don't know D1 + + align:start position:0% +row there let's say as I don't know D1 + + + align:start position:0% +row there let's say as I don't know D1 +d0 or d10 up to D1 n minus one let's say + + align:start position:0% +d0 or d10 up to D1 n minus one let's say + + + align:start position:0% +d0 or d10 up to D1 n minus one let's say +this is the row corresponding to a * + + align:start position:0% +this is the row corresponding to a * + + + align:start position:0% +this is the row corresponding to a * +B if these are different if these are + + align:start position:0% +B if these are different if these are + + + align:start position:0% +B if these are different if these are +different then I have two different + + align:start position:0% +different then I have two different + + + align:start position:0% +different then I have two different +pols that agree in a random out two + + align:start position:0% +pols that agree in a random out two + + + align:start position:0% +pols that agree in a random out two +random degree n minus one pols so the + + align:start position:0% +random degree n minus one pols so the + + + align:start position:0% +random degree n minus one pols so the +polinomial is defined by this row these + + align:start position:0% +polinomial is defined by this row these + + + align:start position:0% +polinomial is defined by this row these +are the coefficients of the polinomial + + align:start position:0% +are the coefficients of the polinomial + + + align:start position:0% +are the coefficients of the polinomial +they're n coefficient so it's a degree n + + align:start position:0% +they're n coefficient so it's a degree n + + + align:start position:0% +they're n coefficient so it's a degree n +minus one polom so + + align:start position:0% +minus one polom so + + + align:start position:0% +minus one polom so +when when would I S when would I accept + + align:start position:0% +when when would I S when would I accept + + + align:start position:0% +when when would I S when would I accept +a false claim if there exist two things + + align:start position:0% +a false claim if there exist two things + + + align:start position:0% +a false claim if there exist two things +that are equal that are different to + + align:start position:0% +that are equal that are different to + + + align:start position:0% +that are equal that are different to +there exists a row in in C that's + + align:start position:0% +there exists a row in in C that's + + + align:start position:0% +there exists a row in in C that's +different than a row in a * + + align:start position:0% +different than a row in a * + + + align:start position:0% +different than a row in a * +B so there exists a polinomial degree in + + align:start position:0% +B so there exists a polinomial degree in + + + align:start position:0% +B so there exists a polinomial degree in +minus one here and a different + + align:start position:0% +minus one here and a different + + + align:start position:0% +minus one here and a different +polinomial degree and minus one and + + align:start position:0% +polinomial degree and minus one and + + + align:start position:0% +polinomial degree and minus one and +these two pols are equal and this + + align:start position:0% + + + + align:start position:0% + +are but what is the probability that two + + align:start position:0% +are but what is the probability that two + + + align:start position:0% +are but what is the probability that two +distinct polinomial of degree n minus + + align:start position:0% +distinct polinomial of degree n minus + + + align:start position:0% +distinct polinomial of degree n minus +one are equal it's just this happens + + align:start position:0% +one are equal it's just this happens + + + align:start position:0% +one are equal it's just this happens +with + + align:start position:0% +with + + + align:start position:0% +with +probability at most n minus one the + + align:start position:0% +probability at most n minus one the + + + align:start position:0% +probability at most n minus one the +degree divided by the field + + align:start position:0% +degree divided by the field + + + align:start position:0% +degree divided by the field +sides right two pooms agree two distinct + + align:start position:0% +sides right two pooms agree two distinct + + + align:start position:0% +sides right two pooms agree two distinct +pols agree on at most or the fraction + + align:start position:0% +pols agree on at most or the fraction + + + align:start position:0% +pols agree on at most or the fraction +not they agree on at most n minus one + + align:start position:0% +not they agree on at most n minus one + + + align:start position:0% +not they agree on at most n minus one +points and which is nus one over F + + align:start position:0% +points and which is nus one over F + + + align:start position:0% +points and which is nus one over F +fraction of + + align:start position:0% +fraction of + + + align:start position:0% +fraction of +the of the field + + align:start position:0% +the of the field + + + align:start position:0% +the of the field +so so that so I'll I'll reject with this + + align:start position:0% +so so that so I'll I'll reject with this + + + align:start position:0% +so so that so I'll I'll reject with this +probability and if we're not happy with + + align:start position:0% +probability and if we're not happy with + + + align:start position:0% +probability and if we're not happy with +this F is f is not big enough for us + + align:start position:0% +this F is f is not big enough for us + + + align:start position:0% +this F is f is not big enough for us +then we do everything over a bigger + + align:start position:0% +then we do everything over a bigger + + + align:start position:0% +then we do everything over a bigger +extension field so we can except so our + + align:start position:0% +extension field so we can except so our + + + align:start position:0% +extension field so we can except so our +rejection probability will be uh high if + + align:start position:0% +rejection probability will be uh high if + + + align:start position:0% +rejection probability will be uh high if +if if the claims + + align:start position:0% +if if the claims + + + align:start position:0% +if if the claims +Falls any any questions about + + align:start position:0% +Falls any any questions about + + + align:start position:0% +Falls any any questions about +this okay so so far what we saw is that + + align:start position:0% +this okay so so far what we saw is that + + + align:start position:0% +this okay so so far what we saw is that +when oh yeah oh yes please thank you + + align:start position:0% +when oh yeah oh yes please thank you + + + align:start position:0% +when oh yeah oh yes please thank you +is this is not short zipa short zipa is + + align:start position:0% +is this is not short zipa short zipa is + + + align:start position:0% +is this is not short zipa short zipa is +similar but in a multivariant setting so + + align:start position:0% +similar but in a multivariant setting so + + + align:start position:0% +similar but in a multivariant setting so +this good so let me that's a good + + align:start position:0% +this good so let me that's a good + + + align:start position:0% +this good so let me that's a good +question so thank you so uh I just want + + align:start position:0% +question so thank you so uh I just want + + + align:start position:0% +question so thank you so uh I just want +to say oh by the way I should tell you + + align:start position:0% +to say oh by the way I should tell you + + + align:start position:0% +to say oh by the way I should tell you +guys this this uh this is being recorded + + align:start position:0% +guys this this uh this is being recorded + + + align:start position:0% +guys this this uh this is being recorded +I hope it's okay with you you're not + + align:start position:0% +I hope it's okay with you you're not + + + align:start position:0% +I hope it's okay with you you're not +being recorded it's supposed I'm + + align:start position:0% +being recorded it's supposed I'm + + + align:start position:0% +being recorded it's supposed I'm +supposed to be the one being recorded + + align:start position:0% +supposed to be the one being recorded + + + align:start position:0% +supposed to be the one being recorded +but I think you should know that there's + + align:start position:0% +but I think you should know that there's + + + align:start position:0% +but I think you should know that there's +a cameraman behind you uh but actually I + + align:start position:0% +a cameraman behind you uh but actually I + + + align:start position:0% +a cameraman behind you uh but actually I +don't I don't think I'm going to put + + align:start position:0% +don't I don't think I'm going to put + + + align:start position:0% +don't I don't think I'm going to put +this public I mean it's in the website + + align:start position:0% +this public I mean it's in the website + + + align:start position:0% +this public I mean it's in the website +for us well now the website is public so + + align:start position:0% +for us well now the website is public so + + + align:start position:0% +for us well now the website is public so +it will be public + + align:start position:0% + + + + align:start position:0% + +I I can make it private if you prefer if + + align:start position:0% +I I can make it private if you prefer if + + + align:start position:0% +I I can make it private if you prefer if +if people come to me and ask for it to + + align:start position:0% +if people come to me and ask for it to + + + align:start position:0% +if people come to me and ask for it to +be private I'll make it private um okay + + align:start position:0% +be private I'll make it private um okay + + + align:start position:0% +be private I'll make it private um okay +uh so uh good so the question was was + + align:start position:0% +uh so uh good so the question was was + + + align:start position:0% +uh so uh good so the question was was +this short zipa and the answer exact + + align:start position:0% +this short zipa and the answer exact + + + align:start position:0% +this short zipa and the answer exact +short zipa is a multivariate version of + + align:start position:0% +short zipa is a multivariate version of + + + align:start position:0% +short zipa is a multivariate version of +this okay this is for the single variate + + align:start position:0% +this okay this is for the single variate + + + align:start position:0% +this okay this is for the single variate +case so the fact that two univariate + + align:start position:0% +case so the fact that two univariate + + + align:start position:0% +case so the fact that two univariate +polinomial of degree D distinct they're + + align:start position:0% +polinomial of degree D distinct they're + + + align:start position:0% +polinomial of degree D distinct they're +equal and a random value their equal and + + align:start position:0% +equal and a random value their equal and + + + align:start position:0% +equal and a random value their equal and +most D element D being the degree uh is + + align:start position:0% +most D element D being the degree uh is + + + align:start position:0% +most D element D being the degree uh is +uh is kind of I don't remember theorem + + align:start position:0% +uh is kind of I don't remember theorem + + + align:start position:0% +uh is kind of I don't remember theorem +like basic something + + align:start position:0% +like basic something + + + align:start position:0% +like basic something +M you say interation yeah but CH is + + align:start position:0% +M you say interation yeah but CH is + + + align:start position:0% +M you say interation yeah but CH is +exactly that but the multivariant + + align:start position:0% +exactly that but the multivariant + + + align:start position:0% +exactly that but the multivariant +setting so a generalization of exactly + + align:start position:0% +setting so a generalization of exactly + + + align:start position:0% +setting so a generalization of exactly +exactly the tral is exactly + + align:start position:0% +exactly the tral is exactly + + + align:start position:0% +exactly the tral is exactly +generalization of this the it will come + + align:start position:0% +generalization of this the it will come + + + align:start position:0% +generalization of this the it will come +up actually later in this class so yeah + + align:start position:0% +up actually later in this class so yeah + + + align:start position:0% +up actually later in this class so yeah +we'll talk about that great any other + + align:start position:0% +we'll talk about that great any other + + + align:start position:0% +we'll talk about that great any other +question + + align:start position:0% + + + + align:start position:0% + +yeah good good good very good question + + align:start position:0% +yeah good good good very good question + + + align:start position:0% +yeah good good good very good question +so the question is can are do we have + + align:start position:0% +so the question is can are do we have + + + align:start position:0% +so the question is can are do we have +examples where Randomness gives you more + + align:start position:0% +examples where Randomness gives you more + + + align:start position:0% +examples where Randomness gives you more +speed up than just kind of pathetic this + + align:start position:0% +speed up than just kind of pathetic this + + + align:start position:0% +speed up than just kind of pathetic this +is not very interesting right so or in + + align:start position:0% +is not very interesting right so or in + + + align:start position:0% +is not very interesting right so or in +other words let me rephrase your + + align:start position:0% +other words let me rephrase your + + + align:start position:0% +other words let me rephrase your +question is the class ma different than + + align:start position:0% +question is the class ma different than + + + align:start position:0% +question is the class ma different than +NP that's the question we don't + + align:start position:0% +NP that's the question we don't + + + align:start position:0% +NP that's the question we don't +know so ma said that the + + align:start position:0% +know so ma said that the + + + align:start position:0% +know so ma said that the +verif yeah so the yeah so all and okay + + align:start position:0% +verif yeah so the yeah so all and okay + + + align:start position:0% +verif yeah so the yeah so all and okay +so yeah so let me explain uh there's a + + align:start position:0% +so yeah so let me explain uh there's a + + + align:start position:0% +so yeah so let me explain uh there's a +kind of there's this class called like m + + align:start position:0% +kind of there's this class called like m + + + align:start position:0% +kind of there's this class called like m +a m a ma a as many as you want and the + + align:start position:0% +a m a ma a as many as you want and the + + + align:start position:0% +a m a ma a as many as you want and the +idea is m means Merlin speaks mlin is + + align:start position:0% +idea is m means Merlin speaks mlin is + + + align:start position:0% +idea is m means Merlin speaks mlin is +the approver he's the wizard a means + + align:start position:0% +the approver he's the wizard a means + + + align:start position:0% +the approver he's the wizard a means +Arthur the king he's the verifier + + align:start position:0% +Arthur the king he's the verifier + + + align:start position:0% +Arthur the king he's the verifier +answers M speaks a answers M speak a + + align:start position:0% +answers M speaks a answers M speak a + + + align:start position:0% +answers M speaks a answers M speak a +answers so there's kind of these classes + + align:start position:0% +answers so there's kind of these classes + + + align:start position:0% +answers so there's kind of these classes +uh you know Ma a ma ma ma + + align:start position:0% +uh you know Ma a ma ma ma + + + align:start position:0% +uh you know Ma a ma ma ma +uh here ma a means M the Merlin speaks + + align:start position:0% +uh here ma a means M the Merlin speaks + + + align:start position:0% +uh here ma a means M the Merlin speaks +Arthur kind of uses Randomness and then + + align:start position:0% +Arthur kind of uses Randomness and then + + + align:start position:0% +Arthur kind of uses Randomness and then +kind of sends Randomness well he doesn't + + align:start position:0% +kind of sends Randomness well he doesn't + + + align:start position:0% +kind of sends Randomness well he doesn't +speak mlin doesn't speak again so but + + align:start position:0% +speak mlin doesn't speak again so but + + + align:start position:0% +speak mlin doesn't speak again so but +Merlin speaks Arthur chooses coins and + + align:start position:0% +Merlin speaks Arthur chooses coins and + + + align:start position:0% +Merlin speaks Arthur chooses coins and +then there's a verdict function that + + align:start position:0% +then there's a verdict function that + + + align:start position:0% +then there's a verdict function that +decides to accept or + + align:start position:0% +decides to accept or + + + align:start position:0% +decides to accept or +reject okay and we don't know if ma is + + align:start position:0% +reject okay and we don't know if ma is + + + align:start position:0% +reject okay and we don't know if ma is +different than NP yes so this actually + + align:start position:0% +different than NP yes so this actually + + + align:start position:0% +different than NP yes so this actually +is a you know po identity testing right + + align:start position:0% +is a you know po identity testing right + + + align:start position:0% +is a you know po identity testing right +right like you saying this is like poom + + align:start position:0% +right like you saying this is like poom + + + align:start position:0% +right like you saying this is like poom +identity yes I give you a circuit + + align:start position:0% +identity yes I give you a circuit + + + align:start position:0% +identity yes I give you a circuit +supp I claim + + align:start position:0% +supp I claim + + + align:start position:0% +supp I claim +that you can check it + + align:start position:0% + + + + align:start position:0% + +clearly right right + + align:start position:0% +clearly right right + + + align:start position:0% +clearly right right +right right but uh oh you're saying + + align:start position:0% +right right but uh oh you're saying + + + align:start position:0% +right right but uh oh you're saying +you're saying sorry you're saying to + + align:start position:0% +you're saying sorry you're saying to + + + align:start position:0% +you're saying sorry you're saying to +test whether a circuit is a identically + + align:start position:0% +test whether a circuit is a identically + + + align:start position:0% +test whether a circuit is a identically +zero but wait oh you're giving us just + + align:start position:0% +zero but wait oh you're giving us just + + + align:start position:0% +zero but wait oh you're giving us just +as as a circuit as a circuit testing if + + align:start position:0% +as as a circuit as a circuit testing if + + + align:start position:0% +as as a circuit as a circuit testing if +it's identically zero + + align:start position:0% +it's identically zero + + + align:start position:0% +it's identically zero +but if it needs to be low degree because + + align:start position:0% +but if it needs to be low degree because + + + align:start position:0% +but if it needs to be low degree because +otherwise so like it's syntactically low + + align:start position:0% +otherwise so like it's syntactically low + + + align:start position:0% +otherwise so like it's syntactically low +degree right low dep or something right + + align:start position:0% +degree right low dep or something right + + + align:start position:0% +degree right low dep or something right +low depth aritic CC low depth like log + + align:start position:0% +low depth aritic CC low depth like log + + + align:start position:0% +low depth aritic CC low depth like log +log depth arithmetic circuit then you're + + align:start position:0% +log depth arithmetic circuit then you're + + + align:start position:0% +log depth arithmetic circuit then you're +saying it has polinomial degree it has + + align:start position:0% +saying it has polinomial degree it has + + + align:start position:0% +saying it has polinomial degree it has +polinomial degree you can test it by + + align:start position:0% +polinomial degree you can test it by + + + align:start position:0% +polinomial degree you can test it by +taking a large field it's sent field you + + align:start position:0% +taking a large field it's sent field you + + + align:start position:0% +taking a large field it's sent field you +can test you don't know how to predict + + align:start position:0% +can test you don't know how to predict + + + align:start position:0% +can test you don't know how to predict +if it's yes good we don't know how to D + + align:start position:0% +if it's yes good we don't know how to D + + + align:start position:0% +if it's yes good we don't know how to D +randomize it how to Der randomize + + align:start position:0% +randomize it how to Der randomize + + + align:start position:0% +randomize it how to Der randomize +randomize it then there are circulars + + align:start position:0% +randomize it then there are circulars + + + align:start position:0% +randomize it then there are circulars +which means you can randomize everything + + align:start position:0% +which means you can randomize everything + + + align:start position:0% +which means you can randomize everything +probably right more + + align:start position:0% +probably right more + + + align:start position:0% +probably right more +less you + + align:start position:0% +less you + + + align:start position:0% +less you +get yeah yeah + + align:start position:0% + + + + align:start position:0% + +Al no why why is it n so so you look at + + align:start position:0% +Al no why why is it n so so you look at + + + align:start position:0% +Al no why why is it n so so you look at +the + + align:start position:0% + + + + align:start position:0% + +CL also right okay okay yeah yeah yeah + + align:start position:0% +CL also right okay okay yeah yeah yeah + + + align:start position:0% +CL also right okay okay yeah yeah yeah +yeah yeah you're right it's in BPP + + align:start position:0% +yeah yeah you're right it's in BPP + + + align:start position:0% +yeah yeah you're right it's in BPP +yeah so I just wanted to make the point + + align:start position:0% +yeah so I just wanted to make the point + + + align:start position:0% +yeah so I just wanted to make the point +that I describe is essentially the the + + align:start position:0% +that I describe is essentially the the + + + align:start position:0% +that I describe is essentially the the +only canonical problem in okay yeah yeah + + align:start position:0% +only canonical problem in okay yeah yeah + + + align:start position:0% +only canonical problem in okay yeah yeah +up to up to details which I + + align:start position:0% + + + + align:start position:0% + +think thanks thanks yeah okay so uh okay + + align:start position:0% +think thanks thanks yeah okay so uh okay + + + align:start position:0% +think thanks thanks yeah okay so uh okay +so now let's go in ahead and just Define + + align:start position:0% +so now let's go in ahead and just Define + + + align:start position:0% +so now let's go in ahead and just Define +this class of NP + + align:start position:0% + + + + align:start position:0% + +uh of of Ip are interactive proofs so + + align:start position:0% +uh of of Ip are interactive proofs so + + + align:start position:0% +uh of of Ip are interactive proofs so +and then we'll show how kind of uh an + + align:start position:0% +and then we'll show how kind of uh an + + + align:start position:0% +and then we'll show how kind of uh an +actual uh to and we'll actually show why + + align:start position:0% +actual uh to and we'll actually show why + + + align:start position:0% +actual uh to and we'll actually show why +we believe this class is more powerful + + align:start position:0% +we believe this class is more powerful + + + align:start position:0% +we believe this class is more powerful +then NP will give kind of a a protocol + + align:start position:0% +then NP will give kind of a a protocol + + + align:start position:0% +then NP will give kind of a a protocol +that solves a problem that seems pretty + + align:start position:0% +that solves a problem that seems pretty + + + align:start position:0% +that solves a problem that seems pretty +hard so let's + + align:start position:0% +hard so let's + + + align:start position:0% +hard so let's +see so here is the so what is an + + align:start position:0% +see so here is the so what is an + + + align:start position:0% +see so here is the so what is an +interactive + + align:start position:0% + + + + align:start position:0% + +proof an interractive proof + + align:start position:0% + + + + align:start position:0% + +IP this is a + + align:start position:0% +IP this is a + + + align:start position:0% +IP this is a +[Music] + + align:start position:0% + + + + align:start position:0% + +protocol + + align:start position:0% + + + + align:start position:0% + +between and + + align:start position:0% +between and + + + align:start position:0% +between and +possibly all powerful okay I'm + + align:start position:0% + + + + align:start position:0% + +not + + align:start position:0% +not + + + align:start position:0% +not +aover + + align:start position:0% +aover + + + align:start position:0% +aover +P okay so P can be run as long as he + + align:start position:0% +P okay so P can be run as long as he + + + align:start position:0% +P okay so P can be run as long as he +wants and a poly + + align:start position:0% + + + + align:start position:0% + +time + + align:start position:0% +time + + + align:start position:0% +time +verifier + + align:start position:0% +verifier + + + align:start position:0% +verifier +v such that here's the requirement want + + align:start position:0% +v such that here's the requirement want + + + align:start position:0% +v such that here's the requirement want +from from the protocol we want to say + + align:start position:0% +from from the protocol we want to say + + + align:start position:0% +from from the protocol we want to say +that a so interactive protocol let's say + + align:start position:0% +that a so interactive protocol let's say + + + align:start position:0% +that a so interactive protocol let's say +for H sorry between a + + align:start position:0% +for H sorry between a + + + align:start position:0% +for H sorry between a +p for a language l + + align:start position:0% + + + + align:start position:0% + +for some + + align:start position:0% +for some + + + align:start position:0% +for some +language or some problem l so the + + align:start position:0% +language or some problem l so the + + + align:start position:0% +language or some problem l so the +problem correspondent is membership in L + + align:start position:0% +problem correspondent is membership in L + + + align:start position:0% +problem correspondent is membership in L +that's a problem is X a member not a + + align:start position:0% +that's a problem is X a member not a + + + align:start position:0% +that's a problem is X a member not a +member so an interactive proof should + + align:start position:0% +member so an interactive proof should + + + align:start position:0% +member so an interactive proof should +satisfy the following so it's a protocol + + align:start position:0% +satisfy the following so it's a protocol + + + align:start position:0% +satisfy the following so it's a protocol +such that it should have two properties + + align:start position:0% +such that it should have two properties + + + align:start position:0% +such that it should have two properties +completeness and + + align:start position:0% +completeness and + + + align:start position:0% +completeness and +soundness completeness says + + align:start position:0% + + + + align:start position:0% + +that if x is in the language the PO + + align:start position:0% +that if x is in the language the PO + + + align:start position:0% +that if x is in the language the PO +should convince you to + + align:start position:0% +should convince you to + + + align:start position:0% +should convince you to +accept Okay so if for every X in the + + align:start position:0% +accept Okay so if for every X in the + + + align:start position:0% +accept Okay so if for every X in the +language if you look if you denote let's + + align:start position:0% +language if you look if you denote let's + + + align:start position:0% +language if you look if you denote let's +say by T the transcript so let's say + + align:start position:0% +say by T the transcript so let's say + + + align:start position:0% +say by T the transcript so let's say +p uh and V which has secret Randomness + + align:start position:0% +p uh and V which has secret Randomness + + + align:start position:0% +p uh and V which has secret Randomness +the prover doesn't know what it is ahead + + align:start position:0% +the prover doesn't know what it is ahead + + + align:start position:0% +the prover doesn't know what it is ahead +of time and input X let's run this + + align:start position:0% +of time and input X let's run this + + + align:start position:0% +of time and input X let's run this +protocol we get a transcript + + align:start position:0% +protocol we get a transcript + + + align:start position:0% +protocol we get a transcript +okay so the it's an interactive protocol + + align:start position:0% +okay so the it's an interactive protocol + + + align:start position:0% +okay so the it's an interactive protocol +it actually think can think of it the + + align:start position:0% +it actually think can think of it the + + + align:start position:0% +it actually think can think of it the +protocol consists in two phases first + + align:start position:0% +protocol consists in two phases first + + + align:start position:0% +protocol consists in two phases first +there's interaction between the they + + align:start position:0% +there's interaction between the they + + + align:start position:0% +there's interaction between the they +talk back and forth let's denote the + + align:start position:0% +talk back and forth let's denote the + + + align:start position:0% +talk back and forth let's denote the +transcript by T okay often denot like + + align:start position:0% +transcript by T okay often denot like + + + align:start position:0% +transcript by T okay often denot like +like PV that's kind of the protocol the + + align:start position:0% +like PV that's kind of the protocol the + + + align:start position:0% +like PV that's kind of the protocol the +Prov has are both of them know the input + + align:start position:0% +Prov has are both of them know the input + + + align:start position:0% +Prov has are both of them know the input +X they generate a transcript and at the + + align:start position:0% +X they generate a transcript and at the + + + align:start position:0% +X they generate a transcript and at the +end the + + align:start position:0% +end the + + + align:start position:0% +end the +probability that V with his input with + + align:start position:0% +probability that V with his input with + + + align:start position:0% +probability that V with his input with +his uh he gets the transcript the r + + align:start position:0% +his uh he gets the transcript the r + + + align:start position:0% +his uh he gets the transcript the r +Randomness in X the probability that he + + align:start position:0% +Randomness in X the probability that he + + + align:start position:0% +Randomness in X the probability that he +accepts outputs one when we say output + + align:start position:0% +accepts outputs one when we say output + + + align:start position:0% +accepts outputs one when we say output +one we usually mean he + + align:start position:0% +one we usually mean he + + + align:start position:0% +one we usually mean he +accepts is large okay let me call a + + align:start position:0% +accepts is large okay let me call a + + + align:start position:0% +accepts is large okay let me call a +least + + align:start position:0% +least + + + align:start position:0% +least +C so and C is going to be a completeness + + align:start position:0% +C so and C is going to be a completeness + + + align:start position:0% +C so and C is going to be a completeness +parameter so a protocol between p and v + + align:start position:0% +parameter so a protocol between p and v + + + align:start position:0% +parameter so a protocol between p and v +for language L with completeness + + align:start position:0% + + + + align:start position:0% + +C and + + align:start position:0% + + + + align:start position:0% + +soundness + + align:start position:0% + + + + align:start position:0% + +S ah yes I do mean all AC now oh thank + + align:start position:0% + + + + align:start position:0% + +you thanks + + align:start position:0% + + + + align:start position:0% + +L okay so if it's in the language he's + + align:start position:0% +L okay so if it's in the language he's + + + align:start position:0% +L okay so if it's in the language he's +accepted with high probability there's + + align:start position:0% +accepted with high probability there's + + + align:start position:0% +accepted with high probability there's +some complet this parameter C and most + + align:start position:0% +some complet this parameter C and most + + + align:start position:0% +some complet this parameter C and most +of what we see in class that AC is one + + align:start position:0% +of what we see in class that AC is one + + + align:start position:0% +of what we see in class that AC is one +okay you accept with probability one and + + align:start position:0% +okay you accept with probability one and + + + align:start position:0% +okay you accept with probability one and +sist + + align:start position:0% +sist + + + align:start position:0% +sist +says + + align:start position:0% + + + + align:start position:0% + +this sist says that for any X not in the + + align:start position:0% +this sist says that for any X not in the + + + align:start position:0% +this sist says that for any X not in the +language + + align:start position:0% + + + + align:start position:0% + +for every X that's not in the + + align:start position:0% +for every X that's not in the + + + align:start position:0% +for every X that's not in the +language no matter how you try to cheat + + align:start position:0% +language no matter how you try to cheat + + + align:start position:0% +language no matter how you try to cheat +you'll fail okay so for any cheating + + align:start position:0% +you'll fail okay so for any cheating + + + align:start position:0% +you'll fail okay so for any cheating +prover or for any P star because it can + + align:start position:0% +prover or for any P star because it can + + + align:start position:0% +prover or for any P star because it can +be any any Prov that tries to convince + + align:start position:0% +be any any Prov that tries to convince + + + align:start position:0% +be any any Prov that tries to convince +me to + + align:start position:0% +me to + + + align:start position:0% +me to +accept if we the probability for the + + align:start position:0% +accept if we the probability for the + + + align:start position:0% +accept if we the probability for the +same t as above the probability that the + + align:start position:0% +same t as above the probability that the + + + align:start position:0% +same t as above the probability that the +verifier given the transcript the + + align:start position:0% +verifier given the transcript the + + + align:start position:0% +verifier given the transcript the +randomness in X outputs one accepts is + + align:start position:0% +randomness in X outputs one accepts is + + + align:start position:0% +randomness in X outputs one accepts is +at most + + align:start position:0% + + + + align:start position:0% + +s okay so that's if you if it's in the + + align:start position:0% +s okay so that's if you if it's in the + + + align:start position:0% +s okay so that's if you if it's in the +language you should be accept with high + + align:start position:0% +language you should be accept with high + + + align:start position:0% +language you should be accept with high +probability C is high if it's not in the + + align:start position:0% +probability C is high if it's not in the + + + align:start position:0% +probability C is high if it's not in the +language you should accept with small + + align:start position:0% +language you should accept with small + + + align:start position:0% +language you should accept with small +probability s is + + align:start position:0% +probability s is + + + align:start position:0% +probability s is +small + + align:start position:0% +small + + + align:start position:0% +small +okay question about the + + align:start position:0% +okay question about the + + + align:start position:0% +okay question about the +model + + align:start position:0% +model + + + align:start position:0% +model +yeah is there any restriction on S and C + + align:start position:0% +yeah is there any restriction on S and C + + + align:start position:0% +yeah is there any restriction on S and C +or they just right great question uh + + align:start position:0% +or they just right great question uh + + + align:start position:0% +or they just right great question uh +what are snc are they constant so that + + align:start position:0% +what are snc are they constant so that + + + align:start position:0% +what are snc are they constant so that +was my next remark which means that the + + align:start position:0% +was my next remark which means that the + + + align:start position:0% +was my next remark which means that the +question was right in place uh so often + + align:start position:0% +question was right in place uh so often + + + align:start position:0% +question was right in place uh so often +if you look at the literature there + + align:start position:0% +if you look at the literature there + + + align:start position:0% +if you look at the literature there +won't be a mention of s and C and C will + + align:start position:0% +won't be a mention of s and C and C will + + + align:start position:0% +won't be a mention of s and C and C will +be taken to be 2/3 and that's will be + + align:start position:0% +be taken to be 2/3 and that's will be + + + align:start position:0% +be taken to be 2/3 and that's will be +taken to be one3 that's kind of a + + align:start position:0% +taken to be one3 that's kind of a + + + align:start position:0% +taken to be one3 that's kind of a +canonical so when people say there's an + + align:start position:0% +canonical so when people say there's an + + + align:start position:0% +canonical so when people say there's an +inter here's an interactive proof often + + align:start position:0% +inter here's an interactive proof often + + + align:start position:0% +inter here's an interactive proof often +you think of s as 1/3 and C as 2/3 and + + align:start position:0% +you think of s as 1/3 and C as 2/3 and + + + align:start position:0% +you think of s as 1/3 and C as 2/3 and +this seems like very arbitrary and you + + align:start position:0% +this seems like very arbitrary and you + + + align:start position:0% +this seems like very arbitrary and you +should be be alarmed so what what you + + align:start position:0% +should be be alarmed so what what you + + + align:start position:0% +should be be alarmed so what what you +know where do this PL come + + align:start position:0% +know where do this PL come + + + align:start position:0% +know where do this PL come +from I don't I think it's + + align:start position:0% +from I don't I think it's + + + align:start position:0% +from I don't I think it's +theed + + align:start position:0% + + + + align:start position:0% + +exactly exactly so the reason why we + + align:start position:0% +exactly exactly so the reason why we + + + align:start position:0% +exactly exactly so the reason why we +don't care so much about these constants + + align:start position:0% +don't care so much about these constants + + + align:start position:0% +don't care so much about these constants +is because if you have an interactive + + align:start position:0% +is because if you have an interactive + + + align:start position:0% +is because if you have an interactive +proof with a gap between CNS so for + + align:start position:0% +proof with a gap between CNS so for + + + align:start position:0% +proof with a gap between CNS so for +example 1/3 and 2/3 what we're going to + + align:start position:0% +example 1/3 and 2/3 what we're going to + + + align:start position:0% +example 1/3 and 2/3 what we're going to +do is repeat the protocol so let's say + + align:start position:0% +do is repeat the protocol so let's say + + + align:start position:0% +do is repeat the protocol so let's say +that it's 1/3 and 23 let's repeat the + + align:start position:0% +that it's 1/3 and 23 let's repeat the + + + align:start position:0% +that it's 1/3 and 23 let's repeat the +protocol let's say n times and then + + align:start position:0% +protocol let's say n times and then + + + align:start position:0% +protocol let's say n times and then +we're going to accept if you're closer + + align:start position:0% +we're going to accept if you're closer + + + align:start position:0% +we're going to accept if you're closer +to C and reject if you're closer to to s + + align:start position:0% +to C and reject if you're closer to to s + + + align:start position:0% +to C and reject if you're closer to to s +or if so in other words if you if more + + align:start position:0% +or if so in other words if you if more + + + align:start position:0% +or if so in other words if you if more +than C uh plus s over two like right in + + align:start position:0% +than C uh plus s over two like right in + + + align:start position:0% +than C uh plus s over two like right in +the middle if more than C plus s over + + align:start position:0% +the middle if more than C plus s over + + + align:start position:0% +the middle if more than C plus s over +two are accepted you're going to accept + + align:start position:0% +two are accepted you're going to accept + + + align:start position:0% +two are accepted you're going to accept +if less you're going to reject in in + + align:start position:0% +if less you're going to reject in in + + + align:start position:0% +if less you're going to reject in in +this case of 2/3 and third if let's say + + align:start position:0% +this case of 2/3 and third if let's say + + + align:start position:0% +this case of 2/3 and third if let's say +more than half repeat it many many many + + align:start position:0% +more than half repeat it many many many + + + align:start position:0% +more than half repeat it many many many +times you should accept if it's in the + + align:start position:0% +times you should accept if it's in the + + + align:start position:0% +times you should accept if it's in the +language you should expect to see about + + align:start position:0% +language you should expect to see about + + + align:start position:0% +language you should expect to see about +two3 acceptance if it's not in the + + align:start position:0% +two3 acceptance if it's not in the + + + align:start position:0% +two3 acceptance if it's not in the +language you should expect to see one + + align:start position:0% +language you should expect to see one + + + align:start position:0% +language you should expect to see one +third of them being accepted and if you + + align:start position:0% +third of them being accepted and if you + + + align:start position:0% +third of them being accepted and if you +repeat enough times by the laws of large + + align:start position:0% +repeat enough times by the laws of large + + + align:start position:0% +repeat enough times by the laws of large +numbers you're going to kind of get + + align:start position:0% +numbers you're going to kind of get + + + align:start position:0% +numbers you're going to kind of get +closer and closer to the expectation so + + align:start position:0% +closer and closer to the expectation so + + + align:start position:0% +closer and closer to the expectation so +you're going to be either very close to + + align:start position:0% +you're going to be either very close to + + + align:start position:0% +you're going to be either very close to +the 2/3 if you're in the language or + + align:start position:0% +the 2/3 if you're in the language or + + + align:start position:0% +the 2/3 if you're in the language or +very close to the one3 if you're outside + + align:start position:0% +very close to the one3 if you're outside + + + align:start position:0% +very close to the one3 if you're outside +the language and the the uh like the the + + align:start position:0% +the language and the the uh like the the + + + align:start position:0% +the language and the the uh like the the +there's very strong concentration so if + + align:start position:0% +there's very strong concentration so if + + + align:start position:0% +there's very strong concentration so if +you repeat it let's say n times then now + + align:start position:0% +you repeat it let's say n times then now + + + align:start position:0% +you repeat it let's say n times then now +you're can to be accepted or your the + + align:start position:0% +you're can to be accepted or your the + + + align:start position:0% +you're can to be accepted or your the +soundness and uh completeness Gap would + + align:start position:0% +soundness and uh completeness Gap would + + + align:start position:0% +soundness and uh completeness Gap would +be something like 2 the minus n versus 1 + + align:start position:0% +be something like 2 the minus n versus 1 + + + align:start position:0% +be something like 2 the minus n versus 1 +minus 2 the minus n so you can really + + align:start position:0% +minus 2 the minus n so you can really + + + align:start position:0% +minus 2 the minus n so you can really +kind of uh very fast make these things + + align:start position:0% +kind of uh very fast make these things + + + align:start position:0% +kind of uh very fast make these things +go to zero and one which is why often we + + align:start position:0% +go to zero and one which is why often we + + + align:start position:0% +go to zero and one which is why often we +don't really care about these and you + + align:start position:0% +don't really care about these and you + + + align:start position:0% +don't really care about these and you +can think of them very close to zero and + + align:start position:0% +can think of them very close to zero and + + + align:start position:0% +can think of them very close to zero and +very close to one so if it's in the + + align:start position:0% +very close to one so if it's in the + + + align:start position:0% +very close to one so if it's in the +language you accept probability almost + + align:start position:0% +language you accept probability almost + + + align:start position:0% +language you accept probability almost +one if it's not the language you reject + + align:start position:0% +one if it's not the language you reject + + + align:start position:0% +one if it's not the language you reject +you accept probility almost zero + + align:start position:0% +you accept probility almost zero + + + align:start position:0% +you accept probility almost zero +okay great okay any question about kind + + align:start position:0% +okay great okay any question about kind + + + align:start position:0% +okay great okay any question about kind +of what an interactive uh proof + + align:start position:0% +of what an interactive uh proof + + + align:start position:0% +of what an interactive uh proof +is okay I just want to mention one thing + + align:start position:0% +is okay I just want to mention one thing + + + align:start position:0% +is okay I just want to mention one thing +uh this + + align:start position:0% +uh this + + + align:start position:0% +uh this +notation like PV on input X is + + align:start position:0% +notation like PV on input X is + + + align:start position:0% +notation like PV on input X is +overloaded we use this notation to + + align:start position:0% +overloaded we use this notation to + + + align:start position:0% +overloaded we use this notation to +denote the transcript we also use this + + align:start position:0% +denote the transcript we also use this + + + align:start position:0% +denote the transcript we also use this +notation to denote the verdict function + + align:start position:0% +notation to denote the verdict function + + + align:start position:0% +notation to denote the verdict function +whether V accepts or not and also I'll + + align:start position:0% +whether V accepts or not and also I'll + + + align:start position:0% +whether V accepts or not and also I'll +use that in class and also wherever you + + align:start position:0% +use that in class and also wherever you + + + align:start position:0% +use that in class and also wherever you +read you'll see both of them kind of + + align:start position:0% +read you'll see both of them kind of + + + align:start position:0% +read you'll see both of them kind of +used so it's good to get used to so this + + align:start position:0% +used so it's good to get used to so this + + + align:start position:0% +used so it's good to get used to so this +sometimes denotes the entire transcript + + align:start position:0% +sometimes denotes the entire transcript + + + align:start position:0% +sometimes denotes the entire transcript +sometimes it's just the notes the + + align:start position:0% +sometimes it's just the notes the + + + align:start position:0% +sometimes it's just the notes the +acceptance or ejection bit of of the + + align:start position:0% +acceptance or ejection bit of of the + + + align:start position:0% +acceptance or ejection bit of of the +verifier and it'll be clear in the + + align:start position:0% +verifier and it'll be clear in the + + + align:start position:0% +verifier and it'll be clear in the +context okay so now the question you + + align:start position:0% +context okay so now the question you + + + align:start position:0% +context okay so now the question you +should ask is okay is this uh is this + + align:start position:0% +should ask is okay is this uh is this + + + align:start position:0% +should ask is okay is this uh is this +model more expressive than + + align:start position:0% +model more expressive than + + + align:start position:0% +model more expressive than +NP what can we do with this model how + + align:start position:0% +NP what can we do with this model how + + + align:start position:0% +NP what can we do with this model how +can what's the power of this + + align:start position:0% +can what's the power of this + + + align:start position:0% +can what's the power of this +m so let me actually go to the punchline + + align:start position:0% +m so let me actually go to the punchline + + + align:start position:0% +m so let me actually go to the punchline +and say there's a celebrated result by + + align:start position:0% + + + + align:start position:0% + +Shamir from 92 I + + align:start position:0% +Shamir from 92 I + + + align:start position:0% +Shamir from 92 I +believe and he showed ex he oh this + + align:start position:0% +believe and he showed ex he oh this + + + align:start position:0% +believe and he showed ex he oh this +model is very very powerful and actually + + align:start position:0% +model is very very powerful and actually + + + align:start position:0% +model is very very powerful and actually +you can prove any P space computation in + + align:start position:0% +you can prove any P space computation in + + + align:start position:0% +you can prove any P space computation in +this model namely if I want to prove to + + align:start position:0% +this model namely if I want to prove to + + + align:start position:0% +this model namely if I want to prove to +you any language in P space take any + + align:start position:0% +you any language in P space take any + + + align:start position:0% +you any language in P space take any +language in P space I can prove + + align:start position:0% +language in P space I can prove + + + align:start position:0% +language in P space I can prove +membership in this language to a + + align:start position:0% +membership in this language to a + + + align:start position:0% +membership in this language to a +verifier that only runs in polinomial + + align:start position:0% +verifier that only runs in polinomial + + + align:start position:0% +verifier that only runs in polinomial +time so that's sh so b space we believe + + align:start position:0% +time so that's sh so b space we believe + + + align:start position:0% +time so that's sh so b space we believe +is much much kind of more expressive + + align:start position:0% +is much much kind of more expressive + + + align:start position:0% +is much much kind of more expressive +stronger than NP we actually don't know + + align:start position:0% +stronger than NP we actually don't know + + + align:start position:0% +stronger than NP we actually don't know +how to prove it by the way but we + + align:start position:0% +how to prove it by the way but we + + + align:start position:0% +how to prove it by the way but we +believe that's the + + align:start position:0% +believe that's the + + + align:start position:0% +believe that's the +case uh so we believe this is a much + + align:start position:0% +case uh so we believe this is a much + + + align:start position:0% +case uh so we believe this is a much +stronger kind of uh proof + + align:start position:0% +stronger kind of uh proof + + + align:start position:0% +stronger kind of uh proof +system okay actually before I I'm going + + align:start position:0% +system okay actually before I I'm going + + + align:start position:0% +system okay actually before I I'm going +to show you actually now I'm going to + + align:start position:0% +to show you actually now I'm going to + + + align:start position:0% +to show you actually now I'm going to +give you an example of the kind of the + + align:start position:0% +give you an example of the kind of the + + + align:start position:0% +give you an example of the kind of the +power of this proof system but before I + + align:start position:0% +power of this proof system but before I + + + align:start position:0% +power of this proof system but before I +go into kind of the technicality I want + + align:start position:0% +go into kind of the technicality I want + + + align:start position:0% +go into kind of the technicality I want +to step back for a second and kind of + + align:start position:0% +to step back for a second and kind of + + + align:start position:0% +to step back for a second and kind of +think a little bit about the story here + + align:start position:0% +think a little bit about the story here + + + align:start position:0% +think a little bit about the story here +which is a very nice story so you know + + align:start position:0% +which is a very nice story so you know + + + align:start position:0% +which is a very nice story so you know +this introduction of uh interactive + + align:start position:0% +this introduction of uh interactive + + + align:start position:0% +this introduction of uh interactive +proofs this model came about for the + + align:start position:0% +proofs this model came about for the + + + align:start position:0% +proofs this model came about for the +goal of doing zero knowledge nobody + + align:start position:0% +goal of doing zero knowledge nobody + + + align:start position:0% +goal of doing zero knowledge nobody +thought at that point about whether you + + align:start position:0% +thought at that point about whether you + + + align:start position:0% +thought at that point about whether you +can prove more languages not more + + align:start position:0% +can prove more languages not more + + + align:start position:0% +can prove more languages not more +languag which is the only thing you want + + align:start position:0% +languag which is the only thing you want + + + align:start position:0% +languag which is the only thing you want +is to hide okay I just want to hide why + + align:start position:0% +is to hide okay I just want to hide why + + + align:start position:0% +is to hide okay I just want to hide why +a theorem is true I want to hide the + + align:start position:0% +a theorem is true I want to hide the + + + align:start position:0% +a theorem is true I want to hide the +proof I want to convince you but hide + + align:start position:0% +proof I want to convince you but hide + + + align:start position:0% +proof I want to convince you but hide +that was the only goal uh that kind of + + align:start position:0% +that was the only goal uh that kind of + + + align:start position:0% +that was the only goal uh that kind of +introduced this model and it's kind of + + align:start position:0% +introduced this model and it's kind of + + + align:start position:0% +introduced this model and it's kind of +interesting how kind of very F like also + + align:start position:0% +interesting how kind of very F like also + + + align:start position:0% +interesting how kind of very F like also +who cares about zero knowledge this is a + + align:start position:0% +who cares about zero knowledge this is a + + + align:start position:0% +who cares about zero knowledge this is a +really interesting model let's see what + + align:start position:0% +really interesting model let's see what + + + align:start position:0% +really interesting model let's see what +we can do with it and this kind of open + + align:start position:0% +we can do with it and this kind of open + + + align:start position:0% +we can do with it and this kind of open +our eyes just the idea that we can shift + + align:start position:0% +our eyes just the idea that we can shift + + + align:start position:0% +our eyes just the idea that we can shift +from the traditional way of thinking + + align:start position:0% +from the traditional way of thinking + + + align:start position:0% +from the traditional way of thinking +about proofs to this attractive and + + align:start position:0% +about proofs to this attractive and + + + align:start position:0% +about proofs to this attractive and +randomized randomized land kind of + + align:start position:0% +randomized randomized land kind of + + + align:start position:0% +randomized randomized land kind of +brought about a lot of really really + + align:start position:0% +brought about a lot of really really + + + align:start position:0% +brought about a lot of really really +beautiful and fascinating results + + align:start position:0% +beautiful and fascinating results + + + align:start position:0% +beautiful and fascinating results +including the fact this is the first + + align:start position:0% +including the fact this is the first + + + align:start position:0% +including the fact this is the first +time to realize wow we can prove a lot + + align:start position:0% +time to realize wow we can prove a lot + + + align:start position:0% +time to realize wow we can prove a lot +of ver to a polinomial Time verifier + + align:start position:0% +of ver to a polinomial Time verifier + + + align:start position:0% +of ver to a polinomial Time verifier +much more than what was believed to + + align:start position:0% +much more than what was believed to + + + align:start position:0% +much more than what was believed to +be a what we believed we can do with a + + align:start position:0% +be a what we believed we can do with a + + + align:start position:0% +be a what we believed we can do with a +classical + + align:start position:0% +classical + + + align:start position:0% +classical +proof so this was kind of really I think + + align:start position:0% +proof so this was kind of really I think + + + align:start position:0% +proof so this was kind of really I think +eye opening and very interesting so okay + + align:start position:0% +eye opening and very interesting so okay + + + align:start position:0% +eye opening and very interesting so okay +so now I'm GNA convince you try to + + align:start position:0% +so now I'm GNA convince you try to + + + align:start position:0% +so now I'm GNA convince you try to +convince you of why this + + align:start position:0% +convince you of why this + + + align:start position:0% +convince you of why this +a proof system this model is so powerful + + align:start position:0% +a proof system this model is so powerful + + + align:start position:0% +a proof system this model is so powerful +by giving you an example of things of a + + align:start position:0% +by giving you an example of things of a + + + align:start position:0% +by giving you an example of things of a +problem that I can prove to you using an + + align:start position:0% +problem that I can prove to you using an + + + align:start position:0% +problem that I can prove to you using an +interactive proof that we really don't + + align:start position:0% +interactive proof that we really don't + + + align:start position:0% +interactive proof that we really don't +know how to prove using a classical + + align:start position:0% +know how to prove using a classical + + + align:start position:0% +know how to prove using a classical +proof okay so let me give you the + + align:start position:0% +proof okay so let me give you the + + + align:start position:0% +proof okay so let me give you the +example + + align:start position:0% + + + + align:start position:0% + +so here's the + + align:start position:0% + + + + align:start position:0% + +example so the protocol is called Su + + align:start position:0% + + + + align:start position:0% + +protocol and this I'm going to give you + + align:start position:0% +protocol and this I'm going to give you + + + align:start position:0% +protocol and this I'm going to give you +an interactive this is an interactive + + align:start position:0% +an interactive this is an interactive + + + align:start position:0% +an interactive this is an interactive +proof for the following problem so take + + align:start position:0% +proof for the following problem so take + + + align:start position:0% +proof for the following problem so take +any degree + + align:start position:0% +any degree + + + align:start position:0% +any degree +fix or okay + + align:start position:0% +fix or okay + + + align:start position:0% +fix or okay +given a + + align:start position:0% +given a + + + align:start position:0% +given a +polinomial + + align:start position:0% +polinomial + + + align:start position:0% +polinomial +F let's say from F to the N so + + align:start position:0% +F let's say from F to the N so + + + align:start position:0% +F let's say from F to the N so +multivariate + + align:start position:0% + + + + align:start position:0% + +polinomial of let's take degree D in + + align:start position:0% +polinomial of let's take degree D in + + + align:start position:0% +polinomial of let's take degree D in +each + + align:start position:0% + + + + align:start position:0% + +variable okay I want a proof + + align:start position:0% +variable okay I want a proof + + + align:start position:0% +variable okay I want a proof +that sum of f B1 + + align:start position:0% +that sum of f B1 + + + align:start position:0% +that sum of f B1 +or let me just make sure how do I wrot + + align:start position:0% +or let me just make sure how do I wrot + + + align:start position:0% +or let me just make sure how do I wrot +it + + align:start position:0% +it + + + align:start position:0% +it +down okay + + align:start position:0% +down okay + + + align:start position:0% +down okay +sorry so take any fix + + align:start position:0% + + + + align:start position:0% + +any subset h and + + align:start position:0% +any subset h and + + + align:start position:0% +any subset h and +f you can think of H 01 you can think of + + align:start position:0% +f you can think of H 01 you can think of + + + align:start position:0% +f you can think of H 01 you can think of +a bigger + + align:start position:0% +a bigger + + + align:start position:0% +a bigger +set I want to I want you to convince me + + align:start position:0% +set I want to I want you to convince me + + + align:start position:0% +set I want to I want you to convince me +that Su F of H1 up to hm + + align:start position:0% +that Su F of H1 up to hm + + + align:start position:0% +that Su F of H1 up to hm +for all H1 up to + + align:start position:0% +for all H1 up to + + + align:start position:0% +for all H1 up to +hm in + + align:start position:0% +hm in + + + align:start position:0% +hm in +h is equals some value + + align:start position:0% + + + + align:start position:0% + +beta okay so there's a fixed polinomial + + align:start position:0% +beta okay so there's a fixed polinomial + + + align:start position:0% +beta okay so there's a fixed polinomial +F let's say I know this polinomial I + + align:start position:0% +F let's say I know this polinomial I + + + align:start position:0% +F let's say I know this polinomial I +either it actually has a succinct + + align:start position:0% +either it actually has a succinct + + + align:start position:0% +either it actually has a succinct +circuit or maybe I have Oracle access to + + align:start position:0% +circuit or maybe I have Oracle access to + + + align:start position:0% +circuit or maybe I have Oracle access to +it so I'm a + + align:start position:0% +it so I'm a + + + align:start position:0% +it so I'm a +verifier I'm a verifier I have let's say + + align:start position:0% +verifier I'm a verifier I have let's say + + + align:start position:0% +verifier I'm a verifier I have let's say +I have Oracle access to this polinomial + + align:start position:0% +I have Oracle access to this polinomial + + + align:start position:0% +I have Oracle access to this polinomial +or there are some sync way to compute it + + align:start position:0% +or there are some sync way to compute it + + + align:start position:0% +or there are some sync way to compute it +so I can compute this polinomial easily + + align:start position:0% +so I can compute this polinomial easily + + + align:start position:0% +so I can compute this polinomial easily +let's think for now I have Oracle access + + align:start position:0% +let's think for now I have Oracle access + + + align:start position:0% +let's think for now I have Oracle access +to it so I can kind of query it in some + + align:start position:0% +to it so I can kind of query it in some + + + align:start position:0% +to it so I can kind of query it in some +point and after that and get back an + + align:start position:0% + + + + align:start position:0% + +answer I want you to I want prove you + + align:start position:0% +answer I want you to I want prove you + + + align:start position:0% +answer I want you to I want prove you +you're going to prove to me that the sum + + align:start position:0% +you're going to prove to me that the sum + + + align:start position:0% +you're going to prove to me that the sum +of this polinomial and H to the m points + + align:start position:0% +of this polinomial and H to the m points + + + align:start position:0% +of this polinomial and H to the m points +and all the points there some set H you + + align:start position:0% +and all the points there some set H you + + + align:start position:0% +and all the points there some set H you +can think of H as 01 you can think of it + + align:start position:0% +can think of H as 01 you can think of it + + + align:start position:0% +can think of H as 01 you can think of it +bigger and I want you to sum this iial + + align:start position:0% +bigger and I want you to sum this iial + + + align:start position:0% +bigger and I want you to sum this iial +on all the elements in the set H to the + + align:start position:0% +on all the elements in the set H to the + + + align:start position:0% +on all the elements in the set H to the +N okay all of this is done over some + + align:start position:0% +N okay all of this is done over some + + + align:start position:0% +N okay all of this is done over some +finite field + + align:start position:0% +finite field + + + align:start position:0% +finite field +F and there's a result beta I want to + + align:start position:0% +F and there's a result beta I want to + + + align:start position:0% +F and there's a result beta I want to +prove that this sum is + + align:start position:0% + + + + align:start position:0% + +beta okay that's that's I I'm going to + + align:start position:0% +beta okay that's that's I I'm going to + + + align:start position:0% +beta okay that's that's I I'm going to +show you an interactive proof for this + + align:start position:0% +show you an interactive proof for this + + + align:start position:0% +show you an interactive proof for this +langage now before kind of you guys are + + align:start position:0% +langage now before kind of you guys are + + + align:start position:0% +langage now before kind of you guys are +like seriously why do I care about this + + align:start position:0% +like seriously why do I care about this + + + align:start position:0% +like seriously why do I care about this +language is it interesting where did I + + align:start position:0% +language is it interesting where did I + + + align:start position:0% +language is it interesting where did I +come up with this thing let me tell you + + align:start position:0% +come up with this thing let me tell you + + + align:start position:0% +come up with this thing let me tell you +I think this is + + align:start position:0% +I think this is + + + align:start position:0% +I think this is +the most important protocol in all the + + align:start position:0% +the most important protocol in all the + + + align:start position:0% +the most important protocol in all the +literature and pro systems okay we all + + align:start position:0% +literature and pro systems okay we all + + + align:start position:0% +literature and pro systems okay we all +use this protocol all the time it turns + + align:start position:0% +use this protocol all the time it turns + + + align:start position:0% +use this protocol all the time it turns +out to be super super influential okay + + align:start position:0% +out to be super super influential okay + + + align:start position:0% +out to be super super influential okay +every single thing we'll use from now on + + align:start position:0% +every single thing we'll use from now on + + + align:start position:0% +every single thing we'll use from now on +relies on this protocol okay so it turns + + align:start position:0% +relies on this protocol okay so it turns + + + align:start position:0% +relies on this protocol okay so it turns +out and I'm going to convince you that + + align:start position:0% +out and I'm going to convince you that + + + align:start position:0% +out and I'm going to convince you that +later uh but that this is a very very + + align:start position:0% +later uh but that this is a very very + + + align:start position:0% +later uh but that this is a very very +important actually problem okay if you + + align:start position:0% +important actually problem okay if you + + + align:start position:0% +important actually problem okay if you +have interactive proof for this problem + + align:start position:0% +have interactive proof for this problem + + + align:start position:0% +have interactive proof for this problem +you it kind of gives you rise attrative + + align:start position:0% +you it kind of gives you rise attrative + + + align:start position:0% +you it kind of gives you rise attrative +proof for many many many other + + align:start position:0% +proof for many many many other + + + align:start position:0% +proof for many many many other +problems okay actually we use this if + + align:start position:0% +problems okay actually we use this if + + + align:start position:0% +problems okay actually we use this if +you give me an interactive proof for + + align:start position:0% +you give me an interactive proof for + + + align:start position:0% +you give me an interactive proof for +this problem I can use it to get an + + align:start position:0% +this problem I can use it to get an + + + align:start position:0% +this problem I can use it to get an +interactive proof for all P + + align:start position:0% +interactive proof for all P + + + align:start position:0% +interactive proof for all P +space in kind of a blackbox way so + + align:start position:0% +space in kind of a blackbox way so + + + align:start position:0% +space in kind of a blackbox way so +really this is the heart of coming up + + align:start position:0% +really this is the heart of coming up + + + align:start position:0% +really this is the heart of coming up +with interactive proofs this is the most + + align:start position:0% +with interactive proofs this is the most + + + align:start position:0% +with interactive proofs this is the most +important interactive + + align:start position:0% +important interactive + + + align:start position:0% +important interactive +proof okay so with that let me show you + + align:start position:0% +proof okay so with that let me show you + + + align:start position:0% +proof okay so with that let me show you +the interactive proof for proving + + align:start position:0% +the interactive proof for proving + + + align:start position:0% +the interactive proof for proving +this okay any questions before we jump + + align:start position:0% +this okay any questions before we jump + + + align:start position:0% +this okay any questions before we jump +yeah just H is like one + + align:start position:0% +yeah just H is like one + + + align:start position:0% +yeah just H is like one +dimension exactly H exactly you can + + align:start position:0% +dimension exactly H exactly you can + + + align:start position:0% +dimension exactly H exactly you can +think of H is 01 for example you can + + align:start position:0% +think of H is 01 for example you can + + + align:start position:0% +think of H is 01 for example you can +think of H 012 yeah I mean if two is in + + align:start position:0% +think of H 012 yeah I mean if two is in + + + align:start position:0% +think of H 012 yeah I mean if two is in +the field yeah it's a onedimensional + + align:start position:0% +the field yeah it's a onedimensional + + + align:start position:0% +the field yeah it's a onedimensional +thing right and you sum over so as a the + + align:start position:0% +thing right and you sum over so as a the + + + align:start position:0% +thing right and you sum over so as a the +you sum here over H to the m sides of H + + align:start position:0% +you sum here over H to the m sides of H + + + align:start position:0% +you sum here over H to the m sides of H +to the m elements + + align:start position:0% + + + + align:start position:0% + +uh it can be you sum over all of them + + align:start position:0% +uh it can be you sum over all of them + + + align:start position:0% +uh it can be you sum over all of them +you sum over also like z z z z z one + + align:start position:0% +you sum over also like z z z z z one + + + align:start position:0% +you sum over also like z z z z z one +yeah all yeah H one and each2 do not + + align:start position:0% +yeah all yeah H one and each2 do not + + + align:start position:0% +yeah all yeah H one and each2 do not +need to be distinct at all yeah exactly + + align:start position:0% +need to be distinct at all yeah exactly + + + align:start position:0% +need to be distinct at all yeah exactly +over all possible yeah you Su over H to + + align:start position:0% +over all possible yeah you Su over H to + + + align:start position:0% +over all possible yeah you Su over H to +the m elements each one all all the + + align:start position:0% +the m elements each one all all the + + + align:start position:0% +the m elements each one all all the +possibilities good other + + align:start position:0% +possibilities good other + + + align:start position:0% +possibilities good other +questions thank you yes so degree D in + + align:start position:0% +questions thank you yes so degree D in + + + align:start position:0% +questions thank you yes so degree D in +each variable just means like any + + align:start position:0% +each variable just means like any + + + align:start position:0% +each variable just means like any +variable is exp exactly so yeah let me + + align:start position:0% +variable is exp exactly so yeah let me + + + align:start position:0% +variable is exp exactly so yeah let me +good good great so degree D in each + + align:start position:0% +good good great so degree D in each + + + align:start position:0% +good good great so degree D in each +variable means f is a polinomial so you + + align:start position:0% +variable means f is a polinomial so you + + + align:start position:0% +variable means f is a polinomial so you +can write it as a sum of monomials each + + align:start position:0% +can write it as a sum of monomials each + + + align:start position:0% +can write it as a sum of monomials each +monomial each uh H variable has a degree + + align:start position:0% +monomial each uh H variable has a degree + + + align:start position:0% +monomial each uh H variable has a degree +so I want say if you look at all the + + align:start position:0% +so I want say if you look at all the + + + align:start position:0% +so I want say if you look at all the +monomials each variable has a degree and + + align:start position:0% +monomials each variable has a degree and + + + align:start position:0% +monomials each variable has a degree and +most be in each of the + + align:start position:0% +most be in each of the + + + align:start position:0% +most be in each of the +monomials okay great questions thank you + + align:start position:0% +monomials okay great questions thank you + + + align:start position:0% +monomials okay great questions thank you +any other + + align:start position:0% + + + + align:start position:0% + +questions okay great so let me give you + + align:start position:0% +questions okay great so let me give you + + + align:start position:0% +questions okay great so let me give you +uh the protocol a + + align:start position:0% +uh the protocol a + + + align:start position:0% +uh the protocol a +so let's do + + align:start position:0% + + + + align:start position:0% + +it by the way I want to tell you I get + + align:start position:0% +it by the way I want to tell you I get + + + align:start position:0% +it by the way I want to tell you I get +such satisfactions from your questions + + align:start position:0% +such satisfactions from your questions + + + align:start position:0% +such satisfactions from your questions +so if you just want to make me happy + + align:start position:0% +so if you just want to make me happy + + + align:start position:0% +so if you just want to make me happy +which is a great goal on its own and you + + align:start position:0% +which is a great goal on its own and you + + + align:start position:0% +which is a great goal on its own and you +should ask + + align:start position:0% + + + + align:start position:0% + +questions okay + + align:start position:0% + + + + align:start position:0% + +ready for the protocol okay Pro + + align:start position:0% +ready for the protocol okay Pro + + + align:start position:0% +ready for the protocol okay Pro +convinces a + + align:start position:0% +convinces a + + + align:start position:0% +convinces a +verifier that the sum F on H1 up to + + align:start position:0% +verifier that the sum F on H1 up to + + + align:start position:0% +verifier that the sum F on H1 up to +hn is equal to + + align:start position:0% +hn is equal to + + + align:start position:0% +hn is equal to +Beta where the H is are all elements in + + align:start position:0% +Beta where the H is are all elements in + + + align:start position:0% +Beta where the H is are all elements in +this set H which is in the field we have + + align:start position:0% +this set H which is in the field we have + + + align:start position:0% +this set H which is in the field we have +some fixed field that we're looking over + + align:start position:0% +some fixed field that we're looking over + + + align:start position:0% +some fixed field that we're looking over +okay how would he prove what would what + + align:start position:0% +okay how would he prove what would what + + + align:start position:0% +okay how would he prove what would what +would he do so here is the idea the idea + + align:start position:0% +would he do so here is the idea the idea + + + align:start position:0% +would he do so here is the idea the idea +is the prover will first + + align:start position:0% +is the prover will first + + + align:start position:0% +is the prover will first +send this sum this polinomial but where + + align:start position:0% +send this sum this polinomial but where + + + align:start position:0% +send this sum this polinomial but where +the first variable is EMP is open so he + + align:start position:0% +the first variable is EMP is open so he + + + align:start position:0% +the first variable is EMP is open so he +will + + align:start position:0% + + + + align:start position:0% + +compute he will compute some only over + + align:start position:0% +compute he will compute some only over + + + align:start position:0% +compute he will compute some only over +H2 up to + + align:start position:0% +H2 up to + + + align:start position:0% +H2 up to +hm f of x this is a variable H2 up to hn + + align:start position:0% +hm f of x this is a variable H2 up to hn + + + align:start position:0% +hm f of x this is a variable H2 up to hn +and he will send this over let's call + + align:start position:0% +and he will send this over let's call + + + align:start position:0% +and he will send this over let's call +this G1 of + + align:start position:0% +this G1 of + + + align:start position:0% +this G1 of +X so he sends a univariate + + align:start position:0% +X so he sends a univariate + + + align:start position:0% +X so he sends a univariate +polinomial okay where he sums over H2 to + + align:start position:0% +polinomial okay where he sums over H2 to + + + align:start position:0% +polinomial okay where he sums over H2 to +hm but leaves the first variable + + align:start position:0% +hm but leaves the first variable + + + align:start position:0% +hm but leaves the first variable +open okay what is the degree of this + + align:start position:0% + + + + align:start position:0% + +polinomial D very good so this is a + + align:start position:0% +polinomial D very good so this is a + + + align:start position:0% +polinomial D very good so this is a +degree d + + align:start position:0% +degree d + + + align:start position:0% +degree d +polinomial the verifier + + align:start position:0% + + + + align:start position:0% + +checks that G1 is of + + align:start position:0% + + + + align:start position:0% + +degree at most D if not he rejects + + align:start position:0% +degree at most D if not he rejects + + + align:start position:0% +degree at most D if not he rejects +because he knows that this is a degree D + + align:start position:0% +because he knows that this is a degree D + + + align:start position:0% +because he knows that this is a degree D +polinomial multivaried + + align:start position:0% +polinomial multivaried + + + align:start position:0% +polinomial multivaried +polinomial so he knows that each + + align:start position:0% +polinomial so he knows that each + + + align:start position:0% +polinomial so he knows that each +variable is the degree most D so if you + + align:start position:0% +variable is the degree most D so if you + + + align:start position:0% +variable is the degree most D so if you +s something degree like you're cheating + + align:start position:0% +s something degree like you're cheating + + + align:start position:0% +s something degree like you're cheating +here so it's going to be reject + + align:start position:0% +here so it's going to be reject + + + align:start position:0% +here so it's going to be reject +you he he will also + + align:start position:0% +you he he will also + + + align:start position:0% +you he he will also +check that + + align:start position:0% + + + + align:start position:0% + +some G1 of H I guess one let me call + + align:start position:0% +some G1 of H I guess one let me call + + + align:start position:0% +some G1 of H I guess one let me call +H1 that if you take G1 and you sum it + + align:start position:0% +H1 that if you take G1 and you sum it + + + align:start position:0% +H1 that if you take G1 and you sum it +over all possible H's in + + align:start position:0% + + + + align:start position:0% + +h what does he expect to get what would + + align:start position:0% +h what does he expect to get what would + + + align:start position:0% +h what does he expect to get what would +he check + + align:start position:0% +he check + + + align:start position:0% +he check +for exactly beta + + align:start position:0% +for exactly beta + + + align:start position:0% +for exactly beta +because the claim is beta so he checks + + align:start position:0% +because the claim is beta so he checks + + + align:start position:0% +because the claim is beta so he checks +that this is a degree + + align:start position:0% +that this is a degree + + + align:start position:0% +that this is a degree +mosd that when you sun over hes you get + + align:start position:0% +mosd that when you sun over hes you get + + + align:start position:0% +mosd that when you sun over hes you get +what was + + align:start position:0% + + + + align:start position:0% + +claimed okay if he's if this does not + + align:start position:0% +claimed okay if he's if this does not + + + align:start position:0% +claimed okay if he's if this does not +hold then he reject he say b i reject + + align:start position:0% +hold then he reject he say b i reject + + + align:start position:0% +hold then he reject he say b i reject +you not going to continue if this holds + + align:start position:0% +you not going to continue if this holds + + + align:start position:0% +you not going to continue if this holds +then he chooses a + + align:start position:0% +then he chooses a + + + align:start position:0% +then he chooses a +random T1 in the + + align:start position:0% +random T1 in the + + + align:start position:0% +random T1 in the +field this is often a notation left + + align:start position:0% +field this is often a notation left + + + align:start position:0% +field this is often a notation left +arrow that we use for choosing a random + + align:start position:0% +arrow that we use for choosing a random + + + align:start position:0% +arrow that we use for choosing a random +okay so he uses a he chooses a random a + + align:start position:0% +okay so he uses a he chooses a random a + + + align:start position:0% +okay so he uses a he chooses a random a +T1 a random element in the field not an + + align:start position:0% +T1 a random element in the field not an + + + align:start position:0% +T1 a random element in the field not an +H but in The Big Field okay you need to + + align:start position:0% +H but in The Big Field okay you need to + + + align:start position:0% +H but in The Big Field okay you need to +think of this field as being big well + + align:start position:0% +think of this field as being big well + + + align:start position:0% +think of this field as being big well +that will the bigger the field the + + align:start position:0% +that will the bigger the field the + + + align:start position:0% +that will the bigger the field the +better the soundless will + + align:start position:0% +better the soundless will + + + align:start position:0% +better the soundless will +get okay so he chooses a random T1 in + + align:start position:0% +get okay so he chooses a random T1 in + + + align:start position:0% +get okay so he chooses a random T1 in +the + + align:start position:0% + + + + align:start position:0% + +field good then what happens the the PO + + align:start position:0% + + + + align:start position:0% + +in some sense this reduces the problem + + align:start position:0% +in some sense this reduces the problem + + + align:start position:0% +in some sense this reduces the problem +from checking that this sum is beta to + + align:start position:0% +from checking that this sum is beta to + + + align:start position:0% +from checking that this sum is beta to +checking + + align:start position:0% +checking + + + align:start position:0% +checking +sum let me WR here to checking that sum + + align:start position:0% +sum let me WR here to checking that sum + + + align:start position:0% +sum let me WR here to checking that sum +of f t t is fixed or T1 you call it and + + align:start position:0% +of f t t is fixed or T1 you call it and + + + align:start position:0% +of f t t is fixed or T1 you call it and +then H2 up to + + align:start position:0% +then H2 up to + + + align:start position:0% +then H2 up to +hn is this fixed I don't know G1 of + + align:start position:0% +hn is this fixed I don't know G1 of + + + align:start position:0% +hn is this fixed I don't know G1 of +T1 we kind of reduce the problem to this + + align:start position:0% +T1 we kind of reduce the problem to this + + + align:start position:0% +T1 we kind of reduce the problem to this +problem which is of one dimension less + + align:start position:0% +problem which is of one dimension less + + + align:start position:0% +problem which is of one dimension less +because the sum is only over M minus one + + align:start position:0% +because the sum is only over M minus one + + + align:start position:0% +because the sum is only over M minus one +variables + + align:start position:0% + + + + align:start position:0% + +yes good what what are we going to put + + align:start position:0% +yes good what what are we going to put + + + align:start position:0% +yes good what what are we going to put +polinomial in very good question when I + + align:start position:0% +polinomial in very good question when I + + + align:start position:0% +polinomial in very good question when I +said that verifier is polinomial time + + align:start position:0% +said that verifier is polinomial time + + + align:start position:0% +said that verifier is polinomial time +polinomial in what so he's going to he's + + align:start position:0% +polinomial in what so he's going to he's + + + align:start position:0% +polinomial in what so he's going to he's +going to be polinomial okay we think of + + align:start position:0% +going to be polinomial okay we think of + + + align:start position:0% +going to be polinomial okay we think of +F I said f can be as Oracle axis to it + + align:start position:0% +F I said f can be as Oracle axis to it + + + align:start position:0% +F I said f can be as Oracle axis to it +so what poom what so he was he what + + align:start position:0% +so what poom what so he was he what + + + align:start position:0% +so what poom what so he was he what +we're we're going to analyze his runtime + + align:start position:0% +we're we're going to analyze his runtime + + + align:start position:0% +we're we're going to analyze his runtime +in a bit but his runtime will depend + + align:start position:0% +in a bit but his runtime will depend + + + align:start position:0% +in a bit but his runtime will depend +polinomial on M which is the number of + + align:start position:0% +polinomial on M which is the number of + + + align:start position:0% +polinomial on M which is the number of +variables and on the + + align:start position:0% +variables and on the + + + align:start position:0% +variables and on the +degree and we think of a in these in to + + align:start position:0% +degree and we think of a in these in to + + + align:start position:0% +degree and we think of a in these in to +today and act like throughout the course + + align:start position:0% +today and act like throughout the course + + + align:start position:0% +today and act like throughout the course +and it's common in this field we think + + align:start position:0% +and it's common in this field we think + + + align:start position:0% +and it's common in this field we think +of f like that he can add and multiply + + align:start position:0% +of f like that he can add and multiply + + + align:start position:0% +of f like that he can add and multiply +things in or order one time like it's a + + align:start position:0% +things in or order one time like it's a + + + align:start position:0% +things in or order one time like it's a +constant uh and typically these fields + + align:start position:0% +constant uh and typically these fields + + + align:start position:0% +constant uh and typically these fields +are going to be take polylog but we + + align:start position:0% +are going to be take polylog but we + + + align:start position:0% +are going to be take polylog but we +don't want to run you know chase after + + align:start position:0% +don't want to run you know chase after + + + align:start position:0% +don't want to run you know chase after +these polog terms so we're not going to + + align:start position:0% +these polog terms so we're not going to + + + align:start position:0% +these polog terms so we're not going to +consider them really sometimes we do + + align:start position:0% +consider them really sometimes we do + + + align:start position:0% +consider them really sometimes we do +sometimes we don't depends but beyond + + align:start position:0% +sometimes we don't depends but beyond + + + align:start position:0% +sometimes we don't depends but beyond +the so if you want to be kind of very + + align:start position:0% +the so if you want to be kind of very + + + align:start position:0% +the so if you want to be kind of very +pedantic then + + align:start position:0% +pedantic then + + + align:start position:0% +pedantic then +you log + + align:start position:0% +you log + + + align:start position:0% +you log +F also H maybe yes thank + + align:start position:0% +F also H maybe yes thank + + + align:start position:0% +F also H maybe yes thank +you yes of course thanks sua the size of + + align:start position:0% +you yes of course thanks sua the size of + + + align:start position:0% +you yes of course thanks sua the size of +H and log + + align:start position:0% +H and log + + + align:start position:0% +H and log +F that's what's going to happen but you + + align:start position:0% +F that's what's going to happen but you + + + align:start position:0% +F that's what's going to happen but you +right that here the polinomial time + + align:start position:0% +right that here the polinomial time + + + align:start position:0% +right that here the polinomial time +doesn't really apply here because you I + + align:start position:0% +doesn't really apply here because you I + + + align:start position:0% +doesn't really apply here because you I +said that he has oralis so we polinomial + + align:start position:0% +said that he has oralis so we polinomial + + + align:start position:0% +said that he has oralis so we polinomial +over so this is this is what he's going + + align:start position:0% +over so this is this is what he's going + + + align:start position:0% +over so this is this is what he's going +to be after but when we're going to use + + align:start position:0% +to be after but when we're going to use + + + align:start position:0% +to be after but when we're going to use +him for applications you'll see it will + + align:start position:0% +him for applications you'll see it will + + + align:start position:0% +him for applications you'll see it will +correspond to polinomial time but we're + + align:start position:0% +correspond to polinomial time but we're + + + align:start position:0% +correspond to polinomial time but we're +going to go over this uh when when uh + + align:start position:0% +going to go over this uh when when uh + + + align:start position:0% +going to go over this uh when when uh +when we analyze the + + align:start position:0% +when we analyze the + + + align:start position:0% +when we analyze the +protocol okay so let's uh okay so let's + + align:start position:0% +protocol okay so let's uh okay so let's + + + align:start position:0% +protocol okay so let's uh okay so let's +just uh uh continue so where let me + + align:start position:0% +just uh uh continue so where let me + + + align:start position:0% +just uh uh continue so where let me +actually start it so what's let me even + + align:start position:0% +actually start it so what's let me even + + + align:start position:0% +actually start it so what's let me even +say before I continue the protocol let's + + align:start position:0% +say before I continue the protocol let's + + + align:start position:0% +say before I continue the protocol let's +continue the protocol with kind of a + + align:start position:0% +continue the protocol with kind of a + + + align:start position:0% +continue the protocol with kind of a +high level idea of what we're trying to + + align:start position:0% +high level idea of what we're trying to + + + align:start position:0% +high level idea of what we're trying to +do here the idea is the + + align:start position:0% +do here the idea is the + + + align:start position:0% +do here the idea is the +following we want to catch aover + + align:start position:0% +following we want to catch aover + + + align:start position:0% +following we want to catch aover +cheating that's the goal of a proof + + align:start position:0% +cheating that's the goal of a proof + + + align:start position:0% +cheating that's the goal of a proof +right we want to catch you if you're + + align:start position:0% +right we want to catch you if you're + + + align:start position:0% +right we want to catch you if you're +cheating so suppose aover is cheating + + align:start position:0% +cheating so suppose aover is cheating + + + align:start position:0% +cheating so suppose aover is cheating +here how will how will he C we catch it + + align:start position:0% +here how will how will he C we catch it + + + align:start position:0% +here how will how will he C we catch it +the way we're going to catch it is when + + align:start position:0% +the way we're going to catch it is when + + + align:start position:0% +the way we're going to catch it is when +tell you know what give me this + + align:start position:0% +tell you know what give me this + + + align:start position:0% +tell you know what give me this +G1 okay now he cannot give me an the + + align:start position:0% +G1 okay now he cannot give me an the + + + align:start position:0% +G1 okay now he cannot give me an the +actual true G1 Because the actual true + + align:start position:0% +actual true G1 Because the actual true + + + align:start position:0% +actual true G1 Because the actual true +G1 will not sum up to Beta beta is the + + align:start position:0% +G1 will not sum up to Beta beta is the + + + align:start position:0% +G1 will not sum up to Beta beta is the +false thing so right so if it if a po + + align:start position:0% +false thing so right so if it if a po + + + align:start position:0% +false thing so right so if it if a po +cheats if he try let I'm trying to kind + + align:start position:0% +cheats if he try let I'm trying to kind + + + align:start position:0% +cheats if he try let I'm trying to kind +of let's come up with this protocol + + align:start position:0% +of let's come up with this protocol + + + align:start position:0% +of let's come up with this protocol +together with kind of the goal of trying + + align:start position:0% +together with kind of the goal of trying + + + align:start position:0% +together with kind of the goal of trying +to catch the the approver so how do we + + align:start position:0% +to catch the the approver so how do we + + + align:start position:0% +to catch the the approver so how do we +catch aover cheating so the IDE is will + + align:start position:0% +catch aover cheating so the IDE is will + + + align:start position:0% +catch aover cheating so the IDE is will +tell me you know what give me this some + + align:start position:0% +tell me you know what give me this some + + + align:start position:0% +tell me you know what give me this some +with this + + align:start position:0% +with this + + + align:start position:0% +with this +open I'm going to check that this sum + + align:start position:0% +open I'm going to check that this sum + + + align:start position:0% +open I'm going to check that this sum +with like that the sum of G1 is equal to + + align:start position:0% +with like that the sum of G1 is equal to + + + align:start position:0% +with like that the sum of G1 is equal to +Beta and then it's low + + align:start position:0% +Beta and then it's low + + + align:start position:0% +Beta and then it's low +degree if it passes then this G1 cannot + + align:start position:0% +degree if it passes then this G1 cannot + + + align:start position:0% +degree if it passes then this G1 cannot +be the true true G1 it can't actually be + + align:start position:0% +be the true true G1 it can't actually be + + + align:start position:0% +be the true true G1 it can't actually be +the real sum of f because the real sum + + align:start position:0% +the real sum of f because the real sum + + + align:start position:0% +the real sum of f because the real sum +of f is not beta he's cheating so this + + align:start position:0% +of f is not beta he's cheating so this + + + align:start position:0% +of f is not beta he's cheating so this +must be a + + align:start position:0% +must be a + + + align:start position:0% +must be a +cheat now when we send in + + align:start position:0% + + + + align:start position:0% + +T1 and we consider kind of so now we + + align:start position:0% +T1 and we consider kind of so now we + + + align:start position:0% +T1 and we consider kind of so now we +send T1 and we kind of reduce the claim + + align:start position:0% +send T1 and we kind of reduce the claim + + + align:start position:0% +send T1 and we kind of reduce the claim +to claiming this + + align:start position:0% +to claiming this + + + align:start position:0% +to claiming this +but with very high probability G1 is + + align:start position:0% +but with very high probability G1 is + + + align:start position:0% +but with very high probability G1 is +also a cheat + + align:start position:0% +also a cheat + + + align:start position:0% +also a cheat +because G1 G1 T1 is a cheat so G1 T1 is + + align:start position:0% +because G1 G1 T1 is a cheat so G1 T1 is + + + align:start position:0% +because G1 G1 T1 is a cheat so G1 T1 is +not really the sum because they're + + align:start position:0% +not really the sum because they're + + + align:start position:0% +not really the sum because they're +different G1 is different than that so + + align:start position:0% +different G1 is different than that so + + + align:start position:0% +different G1 is different than that so +we know that if they're different they + + align:start position:0% +we know that if they're different they + + + align:start position:0% +we know that if they're different they +agree only on D elements okay two + + align:start position:0% +agree only on D elements okay two + + + align:start position:0% +agree only on D elements okay two +distinct polom age only on D elements + + align:start position:0% +distinct polom age only on D elements + + + align:start position:0% +distinct polom age only on D elements +what's the probability that this1 is one + + align:start position:0% +what's the probability that this1 is one + + + align:start position:0% +what's the probability that this1 is one +of the D very small + + align:start position:0% +of the D very small + + + align:start position:0% +of the D very small +DF Okay so think of is really large + + align:start position:0% +DF Okay so think of is really large + + + align:start position:0% +DF Okay so think of is really large +great so this is also false actually you + + align:start position:0% +great so this is also false actually you + + + align:start position:0% +great so this is also false actually you +know he give me G one it's actually not + + align:start position:0% +know he give me G one it's actually not + + + align:start position:0% +know he give me G one it's actually not +the real life he's going to claim it's + + align:start position:0% +the real life he's going to claim it's + + + align:start position:0% +the real life he's going to claim it's +the real life but I know it's not now + + align:start position:0% +the real life but I know it's not now + + + align:start position:0% +the real life but I know it's not now +I'm going to tell him next thing I'm + + align:start position:0% +I'm going to tell him next thing I'm + + + align:start position:0% +I'm going to tell him next thing I'm +going to tell him okay give me G2 G2 is + + align:start position:0% +going to tell him okay give me G2 G2 is + + + align:start position:0% +going to tell him okay give me G2 G2 is +G2 of + + align:start position:0% +G2 of + + + align:start position:0% +G2 of +X is some it should be some f T1 I'm + + align:start position:0% +X is some it should be some f T1 I'm + + + align:start position:0% +X is some it should be some f T1 I'm +going to only sum over H3 up to hm + + align:start position:0% + + + + align:start position:0% + +the X2 the two is going to be open and + + align:start position:0% +the X2 the two is going to be open and + + + align:start position:0% +the X2 the two is going to be open and +then H3 after + + align:start position:0% + + + + align:start position:0% + +H okay so we started by getting rid of + + align:start position:0% +H okay so we started by getting rid of + + + align:start position:0% +H okay so we started by getting rid of +the summing over + + align:start position:0% +the summing over + + + align:start position:0% +the summing over +H1 we gave him the univ pomal or we + + align:start position:0% +H1 we gave him the univ pomal or we + + + align:start position:0% +H1 we gave him the univ pomal or we +chose our R T1 now we're getting rid of + + align:start position:0% +chose our R T1 now we're getting rid of + + + align:start position:0% +chose our R T1 now we're getting rid of +summing over the second + + align:start position:0% +summing over the second + + + align:start position:0% +summing over the second +coordinate we're asking for a univ + + align:start position:0% +coordinate we're asking for a univ + + + align:start position:0% +coordinate we're asking for a univ +polinomial G2 what do we check we check + + align:start position:0% +polinomial G2 what do we check we check + + + align:start position:0% +polinomial G2 what do we check we check +so the verifier checks that + + align:start position:0% +so the verifier checks that + + + align:start position:0% +so the verifier checks that +G2 is of + + align:start position:0% +G2 is of + + + align:start position:0% +G2 is of +degree and most D and what else does he + + align:start position:0% + + + + align:start position:0% + +check very good so sum G2 and + + align:start position:0% +check very good so sum G2 and + + + align:start position:0% +check very good so sum G2 and +H maybe I'll write H2 is equal to what + + align:start position:0% + + + + align:start position:0% + +exactly G1 of + + align:start position:0% +exactly G1 of + + + align:start position:0% +exactly G1 of +T1 so essentially we kind of you know we + + align:start position:0% +T1 so essentially we kind of you know we + + + align:start position:0% +T1 so essentially we kind of you know we +check this for exactly as we did + + align:start position:0% + + + + align:start position:0% + +before okay so now note if in the honest + + align:start position:0% +before okay so now note if in the honest + + + align:start position:0% +before okay so now note if in the honest +case of course that's that's the case G2 + + align:start position:0% +case of course that's that's the case G2 + + + align:start position:0% +case of course that's that's the case G2 +of course is degree at most D because f + + align:start position:0% +of course is degree at most D because f + + + align:start position:0% +of course is degree at most D because f +is degree at most D and when you sum + + align:start position:0% +is degree at most D and when you sum + + + align:start position:0% +is degree at most D and when you sum +with over over all of H2 you should get + + align:start position:0% +with over over all of H2 you should get + + + align:start position:0% +with over over all of H2 you should get +exactly G1 and T that's how + + align:start position:0% +exactly G1 and T that's how + + + align:start position:0% +exactly G1 and T that's how +we + + align:start position:0% +we + + + align:start position:0% +we +great if he's if this does not hold he + + align:start position:0% +great if he's if this does not hold he + + + align:start position:0% +great if he's if this does not hold he +immediately aborts and say I reject you + + align:start position:0% +immediately aborts and say I reject you + + + align:start position:0% +immediately aborts and say I reject you +if he's happy he's going to send T2 at + + align:start position:0% +if he's happy he's going to send T2 at + + + align:start position:0% +if he's happy he's going to send T2 at +random from the + + align:start position:0% + + + + align:start position:0% + +field what am I going to reply with what + + align:start position:0% +field what am I going to reply with what + + + align:start position:0% +field what am I going to reply with what +what should the Prov reply with + + align:start position:0% +what should the Prov reply with + + + align:start position:0% +what should the Prov reply with +so let's see + + align:start position:0% +so let's see + + + align:start position:0% +so let's see +G3 of X is + + align:start position:0% + + + + align:start position:0% + +what very + + align:start position:0% +what very + + + align:start position:0% +what very +good very good F of T1 T2 X and H4 up to + + align:start position:0% + + + + align:start position:0% + +hm yeah again we take essentially what + + align:start position:0% +hm yeah again we take essentially what + + + align:start position:0% +hm yeah again we take essentially what +happened here we reduced after T2 we + + align:start position:0% +happened here we reduced after T2 we + + + align:start position:0% +happened here we reduced after T2 we +reduced the problem to proving a sum + + align:start position:0% +reduced the problem to proving a sum + + + align:start position:0% +reduced the problem to proving a sum +check over sum F1 T1 T2 H3 up to hm and + + align:start position:0% +check over sum F1 T1 T2 H3 up to hm and + + + align:start position:0% +check over sum F1 T1 T2 H3 up to hm and +we need to check whether this is equal + + align:start position:0% +we need to check whether this is equal + + + align:start position:0% +we need to check whether this is equal +to a G2 of + + align:start position:0% +to a G2 of + + + align:start position:0% +to a G2 of +H2 of T2 sorry + + align:start position:0% + + + + align:start position:0% + +okay so again each time we kind of layer + + align:start position:0% +okay so again each time we kind of layer + + + align:start position:0% +okay so again each time we kind of layer +kind of get rid of one variable in the + + align:start position:0% +kind of get rid of one variable in the + + + align:start position:0% +kind of get rid of one variable in the +sum check we start with an narate sum + + align:start position:0% +sum check we start with an narate sum + + + align:start position:0% +sum check we start with an narate sum +check and each round we get rid of one + + align:start position:0% + + + + align:start position:0% + +variable okay last one what do we check + + align:start position:0% +variable okay last one what do we check + + + align:start position:0% +variable okay last one what do we check +here we got G3 what do we check + + align:start position:0% + + + + align:start position:0% + +what is the + + align:start position:0% +what is the + + + align:start position:0% +what is the +g33 exactly so first that G3 is low + + align:start position:0% +g33 exactly so first that G3 is low + + + align:start position:0% +g33 exactly so first that G3 is low +degree is + + align:start position:0% +degree is + + + align:start position:0% +degree is +degree most and some + + align:start position:0% + + + + align:start position:0% + +G3 is + + align:start position:0% +G3 is + + + align:start position:0% +G3 is +G2 and we continueing this way until we + + align:start position:0% +G2 and we continueing this way until we + + + align:start position:0% +G2 and we continueing this way until we +continue continue continue until we got + + align:start position:0% +continue continue continue until we got + + + align:start position:0% +continue continue continue until we got +rid of everything so in the last round + + align:start position:0% +rid of everything so in the last round + + + align:start position:0% +rid of everything so in the last round +what will happen in the last round in + + align:start position:0% +what will happen in the last round in + + + align:start position:0% +what will happen in the last round in +the last + + align:start position:0% +the last + + + align:start position:0% +the last +round we will send + + align:start position:0% +round we will send + + + align:start position:0% +round we will send +g m minus one + + align:start position:0% +g m minus one + + + align:start position:0% +g m minus one +GM of like + + align:start position:0% +GM of like + + + align:start position:0% +GM of like +GMX which is f of T1 up to TN minus1 + + align:start position:0% +GMX which is f of T1 up to TN minus1 + + + align:start position:0% +GMX which is f of T1 up to TN minus1 +X that's what he should check that's + + align:start position:0% +X that's what he should check that's + + + align:start position:0% +X that's what he should check that's +what you should send if you're honest + + align:start position:0% +what you should send if you're honest + + + align:start position:0% +what you should send if you're honest +that's what you send you peeled out off + + align:start position:0% +that's what you send you peeled out off + + + align:start position:0% +that's what you send you peeled out off +everything + + align:start position:0% +everything + + + align:start position:0% +everything +finally you're left with a with a GM + + align:start position:0% +finally you're left with a with a GM + + + align:start position:0% +finally you're left with a with a GM +which is F and M minus one X and then + + align:start position:0% +which is F and M minus one X and then + + + align:start position:0% +which is F and M minus one X and then +the verifier is done he'll choose a + + align:start position:0% +the verifier is done he'll choose a + + + align:start position:0% +the verifier is done he'll choose a +random + + align:start position:0% +random + + + align:start position:0% +random +TM and he will check whether this is + + align:start position:0% +TM and he will check whether this is + + + align:start position:0% +TM and he will check whether this is +indeed F of T1 of the TM we assumed he + + align:start position:0% +indeed F of T1 of the TM we assumed he + + + align:start position:0% +indeed F of T1 of the TM we assumed he +has Oracle access so we can check if + + align:start position:0% +has Oracle access so we can check if + + + align:start position:0% +has Oracle access so we can check if +this value is T1 of the TM okay so + + align:start position:0% +this value is T1 of the TM okay so + + + align:start position:0% +this value is T1 of the TM okay so +finally this is this and + + align:start position:0% +finally this is this and + + + align:start position:0% +finally this is this and +verifier I'm out of room but maybe I'll + + align:start position:0% +verifier I'm out of room but maybe I'll + + + align:start position:0% +verifier I'm out of room but maybe I'll +write + + align:start position:0% +write + + + align:start position:0% +write +here V + + align:start position:0% + + + + align:start position:0% + +chooses uh random TM + + align:start position:0% + + + + align:start position:0% + +and + + align:start position:0% +and + + + align:start position:0% +and +checks that g m of + + align:start position:0% +checks that g m of + + + align:start position:0% +checks that g m of +TM is equal to the Oracle he has F on T1 + + align:start position:0% +TM is equal to the Oracle he has F on T1 + + + align:start position:0% +TM is equal to the Oracle he has F on T1 +up to + + align:start position:0% + + + + align:start position:0% + +T that's the + + align:start position:0% + + + + align:start position:0% + +protocol I'll give you a minute to + + align:start position:0% +protocol I'll give you a minute to + + + align:start position:0% +protocol I'll give you a minute to +appreciate the beauty while I eras the + + align:start position:0% +appreciate the beauty while I eras the + + + align:start position:0% +appreciate the beauty while I eras the +board + + align:start position:0% + + + + align:start position:0% + +you have + + align:start position:0% +you have + + + align:start position:0% +you have +a you're asking can I have a different + + align:start position:0% +a you're asking can I have a different + + + align:start position:0% +a you're asking can I have a different +set I can I can have a different set yes + + align:start position:0% +set I can I can have a different set yes + + + align:start position:0% +set I can I can have a different set yes +yeah so the question was do do the hes + + align:start position:0% +yeah so the question was do do the hes + + + align:start position:0% +yeah so the question was do do the hes +have to be identical and the answers + + align:start position:0% +have to be identical and the answers + + + align:start position:0% +have to be identical and the answers +they don't have to be identical you can + + align:start position:0% +they don't have to be identical you can + + + align:start position:0% +they don't have to be identical you can +take a we didn't use that anywhere and + + align:start position:0% +take a we didn't use that anywhere and + + + align:start position:0% +take a we didn't use that anywhere and +yeah it's somehow yeah somehow we always + + align:start position:0% +yeah it's somehow yeah somehow we always + + + align:start position:0% +yeah it's somehow yeah somehow we always +use it when it is but uh + + align:start position:0% + + + + align:start position:0% + +but but that's a very good point because + + align:start position:0% +but but that's a very good point because + + + align:start position:0% +but but that's a very good point because +it's like it seems more General it seems + + align:start position:0% +it's like it seems more General it seems + + + align:start position:0% +it's like it seems more General it seems +like it can be useful but somehow we + + align:start position:0% +like it can be useful but somehow we + + + align:start position:0% +like it can be useful but somehow we +don't use it + + align:start position:0% + + + + align:start position:0% + +uh but that's a very good good point + + align:start position:0% +uh but that's a very good good point + + + align:start position:0% +uh but that's a very good good point +yeah you can the hes does not have to be + + align:start position:0% +yeah you can the hes does not have to be + + + align:start position:0% +yeah you can the hes does not have to be +the same age you can be some over H1 of + + align:start position:0% +the same age you can be some over H1 of + + + align:start position:0% +the same age you can be some over H1 of +hm so particular H would be equal right + + align:start position:0% +hm so particular H would be equal right + + + align:start position:0% +hm so particular H would be equal right +okay H could be equal uh to F yes H + + align:start position:0% +okay H could be equal uh to F yes H + + + align:start position:0% +okay H could be equal uh to F yes H +could be equal to f um + + align:start position:0% + + + + align:start position:0% + +how do you + + align:start position:0% +how do you + + + align:start position:0% +how do you +do + + align:start position:0% +do + + + align:start position:0% +do +G1 sorry first line Su G1 H1 you will + + align:start position:0% +G1 sorry first line Su G1 H1 you will + + + align:start position:0% +G1 sorry first line Su G1 H1 you will +take time propal yeah but let's say + + align:start position:0% +take time propal yeah but let's say + + + align:start position:0% +take time propal yeah but let's say +that's + + align:start position:0% +that's + + + align:start position:0% +that's +okay again + + align:start position:0% +okay again + + + align:start position:0% +okay again +s yeah so let's we'll talk about + + align:start position:0% +s yeah so let's we'll talk about + + + align:start position:0% +s yeah so let's we'll talk about +soundness in a minute uh actually + + align:start position:0% +soundness in a minute uh actually + + + align:start position:0% +soundness in a minute uh actually +um if f is degree D the sist won't + + align:start position:0% +um if f is degree D the sist won't + + + align:start position:0% +um if f is degree D the sist won't +Decay I actually I think actually a okay + + align:start position:0% +Decay I actually I think actually a okay + + + align:start position:0% +Decay I actually I think actually a okay +let's talk about soundness and then + + align:start position:0% +let's talk about soundness and then + + + align:start position:0% +let's talk about soundness and then +we'll see actually the soundness won't + + align:start position:0% +we'll see actually the soundness won't + + + align:start position:0% +we'll see actually the soundness won't +uh in general usually when H is big in + + align:start position:0% +uh in general usually when H is big in + + + align:start position:0% +uh in general usually when H is big in +applications what happens often is when + + align:start position:0% +applications what happens often is when + + + align:start position:0% +applications what happens often is when +you take big H the F turns out to be + + align:start position:0% +you take big H the F turns out to be + + + align:start position:0% +you take big H the F turns out to be +degree H or H minus one so when we use + + align:start position:0% +degree H or H minus one so when we use + + + align:start position:0% +degree H or H minus one so when we use +this protocol so you know as I said this + + align:start position:0% +this protocol so you know as I said this + + + align:start position:0% +this protocol so you know as I said this +problem I'm say why do I care about this + + align:start position:0% +problem I'm say why do I care about this + + + align:start position:0% +problem I'm say why do I care about this +problem who cares about this problem so + + align:start position:0% +problem who cares about this problem so + + + align:start position:0% +problem who cares about this problem so +it turns out we care a lot it comes up + + align:start position:0% +it turns out we care a lot it comes up + + + align:start position:0% +it turns out we care a lot it comes up +all the time the way we use it in pra + + align:start position:0% +all the time the way we use it in pra + + + align:start position:0% +all the time the way we use it in pra +like the way it comes up is the F that + + align:start position:0% +like the way it comes up is the F that + + + align:start position:0% +like the way it comes up is the F that +we use usually is of degree hus one and + + align:start position:0% +we use usually is of degree hus one and + + + align:start position:0% +we use usually is of degree hus one and +each variable we use it in a way that + + align:start position:0% +each variable we use it in a way that + + + align:start position:0% +each variable we use it in a way that +that turns out to be the degree of F and + + align:start position:0% +that turns out to be the degree of F and + + + align:start position:0% +that turns out to be the degree of F and +the soundness decades with a degree so + + align:start position:0% +the soundness decades with a degree so + + + align:start position:0% +the soundness decades with a degree so +if the H is Big the soundness if the + + align:start position:0% +if the H is Big the soundness if the + + + align:start position:0% +if the H is Big the soundness if the +degree is Big the soundness is big but + + align:start position:0% +degree is Big the soundness is big but + + + align:start position:0% +degree is Big the soundness is big but +actually if your promis that the degree + + align:start position:0% +actually if your promis that the degree + + + align:start position:0% +actually if your promis that the degree +is small then we're good we we'll + + align:start position:0% +is small then we're good we we'll + + + align:start position:0% +is small then we're good we we'll +analyze it right now yeah can you say + + align:start position:0% +analyze it right now yeah can you say + + + align:start position:0% +analyze it right now yeah can you say +something about like what's so special + + align:start position:0% +something about like what's so special + + + align:start position:0% +something about like what's so special +about + + align:start position:0% + + + + align:start position:0% + +yes yes great question love the question + + align:start position:0% +yes yes great question love the question + + + align:start position:0% +yes yes great question love the question +so what what's so fascinating about + + align:start position:0% +so what what's so fascinating about + + + align:start position:0% +so what what's so fascinating about +polinomial that comes up here so the + + align:start position:0% +polinomial that comes up here so the + + + align:start position:0% +polinomial that comes up here so the +what it's kind of why is this so + + align:start position:0% +what it's kind of why is this so + + + align:start position:0% +what it's kind of why is this so +interesting why is colonial so so + + align:start position:0% +interesting why is colonial so so + + + align:start position:0% +interesting why is colonial so so +important you know that this comes up + + align:start position:0% +important you know that this comes up + + + align:start position:0% +important you know that this comes up +everywhere so here's my take and uh on + + align:start position:0% +everywhere so here's my take and uh on + + + align:start position:0% +everywhere so here's my take and uh on +this + + align:start position:0% +this + + + align:start position:0% +this +question everything can be okay first of + + align:start position:0% +question everything can be okay first of + + + align:start position:0% +question everything can be okay first of +all pooms are and St they're very very + + align:start position:0% +all pooms are and St they're very very + + + align:start position:0% +all pooms are and St they're very very +useful because of their their power of + + align:start position:0% +useful because of their their power of + + + align:start position:0% +useful because of their their power of +error correction so in other words what + + align:start position:0% +error correction so in other words what + + + align:start position:0% +error correction so in other words what +happens if you cheat it once we're going + + align:start position:0% +happens if you cheat it once we're going + + + align:start position:0% +happens if you cheat it once we're going +to amplify your cheat that's kind kind + + align:start position:0% +to amplify your cheat that's kind kind + + + align:start position:0% +to amplify your cheat that's kind kind +of what we do here right you cheat it + + align:start position:0% +of what we do here right you cheat it + + + align:start position:0% +of what we do here right you cheat it +once we're g to like for a random Point + + align:start position:0% +once we're g to like for a random Point + + + align:start position:0% +once we're g to like for a random Point +T you're if if you're low degree this + + align:start position:0% +T you're if if you're low degree this + + + align:start position:0% +T you're if if you're low degree this +we're assuming that this Pro gives kind + + align:start position:0% +we're assuming that this Pro gives kind + + + align:start position:0% +we're assuming that this Pro gives kind +of low degree low degree low degree all + + align:start position:0% +of low degree low degree low degree all + + + align:start position:0% +of low degree low degree low degree all +the time if you give low degree low + + align:start position:0% +the time if you give low degree low + + + align:start position:0% +the time if you give low degree low +degree low degree and you cheated then + + align:start position:0% +degree low degree and you cheated then + + + align:start position:0% +degree low degree and you cheated then +the cheat must be kind of corresponding + + align:start position:0% +the cheat must be kind of corresponding + + + align:start position:0% +the cheat must be kind of corresponding +a che a random Point like at the end a + + align:start position:0% +a che a random Point like at the end a + + + align:start position:0% +a che a random Point like at the end a +random Point T1 the TM you should be + + align:start position:0% +random Point T1 the TM you should be + + + align:start position:0% +random Point T1 the TM you should be +different and that's kind of we'll + + align:start position:0% +different and that's kind of we'll + + + align:start position:0% +different and that's kind of we'll +analyze this this is just intuition but + + align:start position:0% +analyze this this is just intuition but + + + align:start position:0% +analyze this this is just intuition but +that kind of the beauty of polinomial + + align:start position:0% +that kind of the beauty of polinomial + + + align:start position:0% +that kind of the beauty of polinomial +that if you're wrong you're wrong almost + + align:start position:0% +that if you're wrong you're wrong almost + + + align:start position:0% +that if you're wrong you're wrong almost +everywhere because if if it's not the + + align:start position:0% +everywhere because if if it's not the + + + align:start position:0% +everywhere because if if it's not the +correct polinomial then it's different + + align:start position:0% +correct polinomial then it's different + + + align:start position:0% +correct polinomial then it's different +from the correct bomal almost everywhere + + align:start position:0% +from the correct bomal almost everywhere + + + align:start position:0% +from the correct bomal almost everywhere +that's the short zip for the multivaried + + align:start position:0% +that's the short zip for the multivaried + + + align:start position:0% +that's the short zip for the multivaried +case for the single varied case it's + + align:start position:0% +case for the single varied case it's + + + align:start position:0% +case for the single varied case it's +just the the interpolation I guess it's + + align:start position:0% +just the the interpolation I guess it's + + + align:start position:0% +just the the interpolation I guess it's +called but okay now you're saying okay + + align:start position:0% +called but okay now you're saying okay + + + align:start position:0% +called but okay now you're saying okay +but that just pomal why am I saying + + align:start position:0% +but that just pomal why am I saying + + + align:start position:0% +but that just pomal why am I saying +comes what's so special about polinomial + + align:start position:0% +comes what's so special about polinomial + + + align:start position:0% +comes what's so special about polinomial +like why why are they so General okay if + + align:start position:0% +like why why are they so General okay if + + + align:start position:0% +like why why are they so General okay if +you happen to have a polinomial good + + align:start position:0% +you happen to have a polinomial good + + + align:start position:0% +you happen to have a polinomial good +good for you you won because it has such + + align:start position:0% +good for you you won because it has such + + + align:start position:0% +good for you you won because it has such +air crafting guarantees you're you're + + align:start position:0% +air crafting guarantees you're you're + + + align:start position:0% +air crafting guarantees you're you're +lucky it's your lucky day but what if + + align:start position:0% +lucky it's your lucky day but what if + + + align:start position:0% +lucky it's your lucky day but what if +it's like why is every day a lucky day + + align:start position:0% +it's like why is every day a lucky day + + + align:start position:0% +it's like why is every day a lucky day +kind of thing why is the poal come up + + align:start position:0% +kind of thing why is the poal come up + + + align:start position:0% +kind of thing why is the poal come up +come up everywhere and the answer is + + align:start position:0% +come up everywhere and the answer is + + + align:start position:0% +come up everywhere and the answer is +that you can actually embed many many + + align:start position:0% +that you can actually embed many many + + + align:start position:0% +that you can actually embed many many +problems into pols so there's a way + + align:start position:0% +problems into pols so there's a way + + + align:start position:0% +problems into pols so there's a way +there's a technique which we'll call low + + align:start position:0% +there's a technique which we'll call low + + + align:start position:0% +there's a technique which we'll call low +degree extension we'll see that pretty + + align:start position:0% +degree extension we'll see that pretty + + + align:start position:0% +degree extension we'll see that pretty +soon soon if not today then tomorrow + + align:start position:0% +soon soon if not today then tomorrow + + + align:start position:0% +soon soon if not today then tomorrow +then next week where uh a a you can kind + + align:start position:0% +then next week where uh a a you can kind + + + align:start position:0% +then next week where uh a a you can kind +of convert many problems into + + align:start position:0% +of convert many problems into + + + align:start position:0% +of convert many problems into +polinomial and then use the sum check so + + align:start position:0% +polinomial and then use the sum check so + + + align:start position:0% +polinomial and then use the sum check so +that's often what we do we take a + + align:start position:0% +that's often what we do we take a + + + align:start position:0% +that's often what we do we take a +problem we embed it into a polom we kind + + align:start position:0% +problem we embed it into a polom we kind + + + align:start position:0% +problem we embed it into a polom we kind +of extend it to look like a polinomial + + align:start position:0% +of extend it to look like a polinomial + + + align:start position:0% +of extend it to look like a polinomial +of low degree and then we use subject to + + align:start position:0% +of low degree and then we use subject to + + + align:start position:0% +of low degree and then we use subject to +it so that's how it will come + + align:start position:0% + + + + align:start position:0% + +up any any more questions before a + + align:start position:0% +up any any more questions before a + + + align:start position:0% +up any any more questions before a +before we analyze the subject protocol + + align:start position:0% +before we analyze the subject protocol + + + align:start position:0% +before we analyze the subject protocol +questions on the protocol + + align:start position:0% +questions on the protocol + + + align:start position:0% +questions on the protocol +itself + + align:start position:0% + + + + align:start position:0% + +or oh oh you're asking what you're + + align:start position:0% +or oh oh you're asking what you're + + + align:start position:0% +or oh oh you're asking what you're +asking you're saying this sum check do I + + align:start position:0% +asking you're saying this sum check do I + + + align:start position:0% +asking you're saying this sum check do I +really need this specific kind of a + + align:start position:0% +really need this specific kind of a + + + align:start position:0% +really need this specific kind of a +polinomial code or can I do using + + align:start position:0% +polinomial code or can I do using + + + align:start position:0% +polinomial code or can I do using +arbitrary codes kind of thing okay so + + align:start position:0% +arbitrary codes kind of thing okay so + + + align:start position:0% +arbitrary codes kind of thing okay so +actually this is a great great question + + align:start position:0% +actually this is a great great question + + + align:start position:0% +actually this is a great great question +uh there's a paper by or + + align:start position:0% +uh there's a paper by or + + + align:start position:0% +uh there's a paper by or +from several years ago I remember + + align:start position:0% +from several years ago I remember + + + align:start position:0% +from several years ago I remember +exactly where he shows how to do a sum + + align:start position:0% +exactly where he shows how to do a sum + + + align:start position:0% +exactly where he shows how to do a sum +check over more General codes not any + + align:start position:0% +check over more General codes not any + + + align:start position:0% +check over more General codes not any +kind of code but more General than that + + align:start position:0% +kind of code but more General than that + + + align:start position:0% +kind of code but more General than that +thing like tensor codes or Rachel do you + + align:start position:0% +thing like tensor codes or Rachel do you + + + align:start position:0% +thing like tensor codes or Rachel do you +remember you looked into it yeah t + + align:start position:0% +remember you looked into it yeah t + + + align:start position:0% +remember you looked into it yeah t +tensor + + align:start position:0% +tensor + + + align:start position:0% +tensor +codes yeah so so he generalized it not + + align:start position:0% +codes yeah so so he generalized it not + + + align:start position:0% +codes yeah so so he generalized it not +to any code but he G the generalization + + align:start position:0% +to any code but he G the generalization + + + align:start position:0% +to any code but he G the generalization +this OC to work for big for a larger + + align:start position:0% +this OC to work for big for a larger + + + align:start position:0% +this OC to work for big for a larger +family + + align:start position:0% +family + + + align:start position:0% +family +of to ask the question what does it mean + + align:start position:0% +of to ask the question what does it mean + + + align:start position:0% +of to ask the question what does it mean +for the subject protocol to work for + + align:start position:0% +for the subject protocol to work for + + + align:start position:0% +for the subject protocol to work for +okay more good good good so you can + + align:start position:0% +okay more good good good so you can + + + align:start position:0% +okay more good good good so you can +think of it is I'm proving something + + align:start position:0% +think of it is I'm proving something + + + align:start position:0% +think of it is I'm proving something +about uh I don't remember exactly how + + align:start position:0% +about uh I don't remember exactly how + + + align:start position:0% +about uh I don't remember exactly how +his formalization was but it's like uh + + align:start position:0% +his formalization was but it's like uh + + + align:start position:0% +his formalization was but it's like uh +I'm proving something about a code + + align:start position:0% +I'm proving something about a code + + + align:start position:0% +I'm proving something about a code +word and I want kind of reinterpret this + + align:start position:0% +word and I want kind of reinterpret this + + + align:start position:0% +word and I want kind of reinterpret this +you can reinterpret this as a because + + align:start position:0% +you can reinterpret this as a because + + + align:start position:0% +you can reinterpret this as a because +you can think of the this F as being an + + align:start position:0% +you can think of the this F as being an + + + align:start position:0% +you can think of the this F as being an +aircraf in code so does it work only for + + align:start position:0% +aircraf in code so does it work only for + + + align:start position:0% +aircraf in code so does it work only for +this kind of read M this is called the + + align:start position:0% +this kind of read M this is called the + + + align:start position:0% +this kind of read M this is called the +read does it work only for read can you + + align:start position:0% +read does it work only for read can you + + + align:start position:0% +read does it work only for read can you +do it for arbitrary codes uh and he + + align:start position:0% +do it for arbitrary codes uh and he + + + align:start position:0% +do it for arbitrary codes uh and he +proves it for for arbitrary codes so + + align:start position:0% +proves it for for arbitrary codes so + + + align:start position:0% +proves it for for arbitrary codes so +this is kind of there's kind of a any + + align:start position:0% +this is kind of there's kind of a any + + + align:start position:0% +this is kind of there's kind of a any +polinomial is an air correcting code + + align:start position:0% +polinomial is an air correcting code + + + align:start position:0% +polinomial is an air correcting code +it's a type of air crafting code H for a + + align:start position:0% +it's a type of air crafting code H for a + + + align:start position:0% +it's a type of air crafting code H for a +multivaried case it's called read Muller + + align:start position:0% +multivaried case it's called read Muller + + + align:start position:0% +multivaried case it's called read Muller +for univ case is called re Solomon and + + align:start position:0% +for univ case is called re Solomon and + + + align:start position:0% +for univ case is called re Solomon and +so when the subject protocol for V think + + align:start position:0% +so when the subject protocol for V think + + + align:start position:0% +so when the subject protocol for V think +it is this protocol for read more codes + + align:start position:0% +it is this protocol for read more codes + + + align:start position:0% +it is this protocol for read more codes +and then you can ask is there a analog + + align:start position:0% +and then you can ask is there a analog + + + align:start position:0% +and then you can ask is there a analog +for other codes and actually there is + + align:start position:0% +for other codes and actually there is + + + align:start position:0% +for other codes and actually there is +there are analogs out there + + align:start position:0% +there are analogs out there + + + align:start position:0% +there are analogs out there +yeah okay any other questions + + align:start position:0% +yeah okay any other questions + + + align:start position:0% +yeah okay any other questions +yeah making the + + align:start position:0% + + + + align:start position:0% + +of that wouldn't like point of doing + + align:start position:0% +of that wouldn't like point of doing + + + align:start position:0% +of that wouldn't like point of doing +this because of like the size of H the + + align:start position:0% +this because of like the size of H the + + + align:start position:0% +this because of like the size of H the +log okay you're right so okay you're + + align:start position:0% +log okay you're right so okay you're + + + align:start position:0% +log okay you're right so okay you're +right so if there okay so the let me go + + align:start position:0% +right so if there okay so the let me go + + + align:start position:0% +right so if there okay so the let me go +back so the question is what what should + + align:start position:0% +back so the question is what what should + + + align:start position:0% +back so the question is what what should +this H be you know what is this H and + + align:start position:0% +this H be you know what is this H and + + + align:start position:0% +this H be you know what is this H and +the answer is this H can actually be all + + align:start position:0% +the answer is this H can actually be all + + + align:start position:0% +the answer is this H can actually be all +of f of course if it's all of f the + + align:start position:0% +of f of course if it's all of f the + + + align:start position:0% +of f of course if it's all of f the +verifier runs in time which is like the + + align:start position:0% +verifier runs in time which is like the + + + align:start position:0% +verifier runs in time which is like the +size of f because he checks you know Su + + align:start position:0% +size of f because he checks you know Su + + + align:start position:0% +size of f because he checks you know Su +over H if it's all of f you run the time + + align:start position:0% +over H if it's all of f you run the time + + + align:start position:0% +over H if it's all of f you run the time +all of f but maybe f is not that big + + align:start position:0% +all of f but maybe f is not that big + + + align:start position:0% +all of f but maybe f is not that big +maybe f is polinomial even if f is + + align:start position:0% +maybe f is polinomial even if f is + + + align:start position:0% +maybe f is polinomial even if f is +polinomial size still checking this sum + + align:start position:0% +polinomial size still checking this sum + + + align:start position:0% +polinomial size still checking this sum +is much bigger than F right it's like H + + align:start position:0% +is much bigger than F right it's like H + + + align:start position:0% +is much bigger than F right it's like H +to the n like f to the m m can be big so + + align:start position:0% +to the n like f to the m m can be big so + + + align:start position:0% +to the n like f to the m m can be big so +the the hardness does not come only from + + align:start position:0% +the the hardness does not come only from + + + align:start position:0% +the the hardness does not come only from +f it comes from M it's exponential in M + + align:start position:0% +f it comes from M it's exponential in M + + + align:start position:0% +f it comes from M it's exponential in M +it's the M that kind of makes it very + + align:start position:0% +it's the M that kind of makes it very + + + align:start position:0% +it's the M that kind of makes it very +hard and so H can be as large as the + + align:start position:0% +hard and so H can be as large as the + + + align:start position:0% +hard and so H can be as large as the +entire field and you can run some check + + align:start position:0% +entire field and you can run some check + + + align:start position:0% +entire field and you can run some check +over that too there's um it's still an + + align:start position:0% +over that too there's um it's still an + + + align:start position:0% +over that too there's um it's still an +interesting protocol yeah but if we that + + align:start position:0% +interesting protocol yeah but if we that + + + align:start position:0% +interesting protocol yeah but if we that +would we need to do an extension or + + align:start position:0% +would we need to do an extension or + + + align:start position:0% +would we need to do an extension or +something that good so okay the good so + + align:start position:0% +something that good so okay the good so + + + align:start position:0% +something that good so okay the good so +the question is wait do we get any + + align:start position:0% +the question is wait do we get any + + + align:start position:0% +the question is wait do we get any +aircraft in guarantees here because uh + + align:start position:0% +aircraft in guarantees here because uh + + + align:start position:0% +aircraft in guarantees here because uh +if we're doing over all of that and I + + align:start position:0% +if we're doing over all of that and I + + + align:start position:0% +if we're doing over all of that and I +think the answer is yes we we don't need + + align:start position:0% +think the answer is yes we we don't need + + + align:start position:0% +think the answer is yes we we don't need +to extend it further because as we see + + align:start position:0% +to extend it further because as we see + + + align:start position:0% +to extend it further because as we see +now we'll see now when we analyze it the + + align:start position:0% +now we'll see now when we analyze it the + + + align:start position:0% +now we'll see now when we analyze it the +soundless error goes down with something + + align:start position:0% +soundless error goes down with something + + + align:start position:0% +soundless error goes down with something +like d over f h does not come into play + + align:start position:0% +like d over f h does not come into play + + + align:start position:0% +like d over f h does not come into play +there but we'll see that let's let's see + + align:start position:0% +there but we'll see that let's let's see + + + align:start position:0% +there but we'll see that let's let's see +that together I I right I agree when you + + align:start position:0% +that together I I right I agree when you + + + align:start position:0% +that together I I right I agree when you +say that yeah that should right it + + align:start position:0% +say that yeah that should right it + + + align:start position:0% +say that yeah that should right it +should things should degrade with age + + align:start position:0% +should things should degrade with age + + + align:start position:0% +should things should degrade with age +but actually they don't so we'll see + + align:start position:0% +but actually they don't so we'll see + + + align:start position:0% +but actually they don't so we'll see +that now when we when we analyze + + align:start position:0% +that now when we when we analyze + + + align:start position:0% +that now when we when we analyze +it okay okay any any these are great + + align:start position:0% +it okay okay any any these are great + + + align:start position:0% +it okay okay any any these are great +great questions so thank you any other + + align:start position:0% +great questions so thank you any other + + + align:start position:0% +great questions so thank you any other +questions before we go to the + + align:start position:0% +questions before we go to the + + + align:start position:0% +questions before we go to the +analysis okay so actually before we do + + align:start position:0% +analysis okay so actually before we do + + + align:start position:0% +analysis okay so actually before we do +soundness let's just first do a sanity + + align:start position:0% +soundness let's just first do a sanity + + + align:start position:0% +soundness let's just first do a sanity +check on the com on the kind of + + align:start position:0% +check on the com on the kind of + + + align:start position:0% +check on the com on the kind of +communication complexity and the the + + align:start position:0% +communication complexity and the the + + + align:start position:0% +communication complexity and the the +runtime and so on so first let's see + + align:start position:0% +runtime and so on so first let's see + + + align:start position:0% +runtime and so on so first let's see +this protocol has n rounds each round we + + align:start position:0% +this protocol has n rounds each round we + + + align:start position:0% +this protocol has n rounds each round we +kind of get rid of one VAR one sum in + + align:start position:0% +kind of get rid of one VAR one sum in + + + align:start position:0% +kind of get rid of one VAR one sum in +the sum check right so + + align:start position:0% +the sum check right so + + + align:start position:0% +the sum check right so +the so uh the communication complexity + + align:start position:0% +the so uh the communication complexity + + + align:start position:0% +the so uh the communication complexity +so our round + + align:start position:0% + + + + align:start position:0% + +complexity is M rounds M back and forth + + align:start position:0% +complexity is M rounds M back and forth + + + align:start position:0% +complexity is M rounds M back and forth +M to m i don't if you want to count each + + align:start position:0% +M to m i don't if you want to count each + + + align:start position:0% +M to m i don't if you want to count each +one or round is one two so let me just + + align:start position:0% +one or round is one two so let me just + + + align:start position:0% +one or round is one two so let me just +say + + align:start position:0% +say + + + align:start position:0% +say +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +order uh the the communication + + align:start position:0% + + + + align:start position:0% + +complexity is what um uh so each time uh + + align:start position:0% +complexity is what um uh so each time uh + + + align:start position:0% +complexity is what um uh so each time uh +po one polinomial is s and one field + + align:start position:0% +po one polinomial is s and one field + + + align:start position:0% +po one polinomial is s and one field +element so it's really a polinomial is a + + align:start position:0% +element so it's really a polinomial is a + + + align:start position:0% +element so it's really a polinomial is a +degree d right so it's just uh D field + + align:start position:0% +degree d right so it's just uh D field + + + align:start position:0% +degree d right so it's just uh D field +elements each time times + + align:start position:0% +elements each time times + + + align:start position:0% +elements each time times +n so fine we can do times you know log F + + align:start position:0% +n so fine we can do times you know log F + + + align:start position:0% +n so fine we can do times you know log F +if you want + + align:start position:0% + + + + align:start position:0% + +to so that's the communication + + align:start position:0% +to so that's the communication + + + align:start position:0% +to so that's the communication +complexity okay what about the verifier + + align:start position:0% +complexity okay what about the verifier + + + align:start position:0% +complexity okay what about the verifier +run time + + align:start position:0% + + + + align:start position:0% + +so the + + align:start position:0% +so the + + + align:start position:0% +so the +verifier he gets a polinomial degree D + + align:start position:0% +verifier he gets a polinomial degree D + + + align:start position:0% +verifier he gets a polinomial degree D +polinomial so D essentially field + + align:start position:0% +polinomial so D essentially field + + + align:start position:0% +polinomial so D essentially field +elements or D plus1 field elements and + + align:start position:0% +elements or D plus1 field elements and + + + align:start position:0% +elements or D plus1 field elements and +he just sums them up he checks that it's + + align:start position:0% +he just sums them up he checks that it's + + + align:start position:0% +he just sums them up he checks that it's +a degree D and sums them up that's all + + align:start position:0% +a degree D and sums them up that's all + + + align:start position:0% +a degree D and sums them up that's all +he does so it's really essentially the + + align:start position:0% +he does so it's really essentially the + + + align:start position:0% +he does so it's really essentially the +same for M rounds he has a degree D + + align:start position:0% +same for M rounds he has a degree D + + + align:start position:0% +same for M rounds he has a degree D +polinomial and he sums them I should put + + align:start position:0% +polinomial and he sums them I should put + + + align:start position:0% +polinomial and he sums them I should put +here maybe po log then because the sum I + + align:start position:0% +here maybe po log then because the sum I + + + align:start position:0% +here maybe po log then because the sum I +I'm assuming addition multiplication + + align:start position:0% +I'm assuming addition multiplication + + + align:start position:0% +I'm assuming addition multiplication +take poly log F again as I said often I + + align:start position:0% +take poly log F again as I said often I + + + align:start position:0% +take poly log F again as I said often I +think maybe even in the notes justtin + + align:start position:0% +think maybe even in the notes justtin + + + align:start position:0% +think maybe even in the notes justtin +Taylor's notes this is omitted it's like + + align:start position:0% +Taylor's notes this is omitted it's like + + + align:start position:0% +Taylor's notes this is omitted it's like +the feel thing of is one operation so + + align:start position:0% +the feel thing of is one operation so + + + align:start position:0% +the feel thing of is one operation so +just so you know if you read things + + align:start position:0% +just so you know if you read things + + + align:start position:0% +just so you know if you read things +often you won't see this part question + + align:start position:0% +often you won't see this part question + + + align:start position:0% +often you won't see this part question +ver the verifier also needs to choose + + align:start position:0% +ver the verifier also needs to choose + + + align:start position:0% +ver the verifier also needs to choose +the + + align:start position:0% + + + + align:start position:0% + +T yeah exactly so some over H is like H + + align:start position:0% +T yeah exactly so some over H is like H + + + align:start position:0% +T yeah exactly so some over H is like H +additions okay okay yeah he you sorry + + align:start position:0% +additions okay okay yeah he you sorry + + + align:start position:0% +additions okay okay yeah he you sorry +yeah so okay good uh you're saying he + + align:start position:0% +yeah so okay good uh you're saying he + + + align:start position:0% +yeah so okay good uh you're saying he +needs to compute uh it's still yeah so + + align:start position:0% +needs to compute uh it's still yeah so + + + align:start position:0% +needs to compute uh it's still yeah so +right so the the ver far he gets a + + align:start position:0% +right so the the ver far he gets a + + + align:start position:0% +right so the the ver far he gets a +polinomial he needs to evaluate the + + align:start position:0% +polinomial he needs to evaluate the + + + align:start position:0% +polinomial he needs to evaluate the +polinomial in h so yeah so for M rounds + + align:start position:0% +polinomial in h so yeah so for M rounds + + + align:start position:0% +polinomial in h so yeah so for M rounds +he gets a degree D polinomial he needs + + align:start position:0% +he gets a degree D polinomial he needs + + + align:start position:0% +he gets a degree D polinomial he needs +to evaluate + + align:start position:0% +to evaluate + + + align:start position:0% +to evaluate +it oh sorry this does not have + + align:start position:0% +it oh sorry this does not have + + + align:start position:0% +it oh sorry this does not have +H yeah you need to evaluate it in in uh + + align:start position:0% +H yeah you need to evaluate it in in uh + + + align:start position:0% +H yeah you need to evaluate it in in uh +H + + align:start position:0% +H + + + align:start position:0% +H +points the degree D polinomial and then + + align:start position:0% +points the degree D polinomial and then + + + align:start position:0% +points the degree D polinomial and then +a + + align:start position:0% + + + + align:start position:0% + +log thanks + + align:start position:0% + + + + align:start position:0% + +good thanks a lot good catch that's + + align:start position:0% +good thanks a lot good catch that's + + + align:start position:0% +good thanks a lot good catch that's +awesome okay great so that's the + + align:start position:0% +awesome okay great so that's the + + + align:start position:0% +awesome okay great so that's the +verifier as I said the PO we care less + + align:start position:0% +verifier as I said the PO we care less + + + align:start position:0% +verifier as I said the PO we care less +about but just you know if you want to + + align:start position:0% +about but just you know if you want to + + + align:start position:0% +about but just you know if you want to +just + + align:start position:0% +just + + + align:start position:0% +just +and and by the way this is assuming the + + align:start position:0% +and and by the way this is assuming the + + + align:start position:0% +and and by the way this is assuming the +verifier has access to F he knows f f is + + align:start position:0% +verifier has access to F he knows f f is + + + align:start position:0% +verifier has access to F he knows f f is +kind of he has Oracle access to it + + align:start position:0% +kind of he has Oracle access to it + + + align:start position:0% +kind of he has Oracle access to it +because of course at the end he needs to + + align:start position:0% +because of course at the end he needs to + + + align:start position:0% +because of course at the end he needs to +check equality with f so this we just + + align:start position:0% +check equality with f so this we just + + + align:start position:0% +check equality with f so this we just +assume he has oral access to F and then + + align:start position:0% +assume he has oral access to F and then + + + align:start position:0% +assume he has oral access to F and then +the prover what he does he need to do + + align:start position:0% +the prover what he does he need to do + + + align:start position:0% +the prover what he does he need to do +well he needs to do this computation so + + align:start position:0% +well he needs to do this computation so + + + align:start position:0% +well he needs to do this computation so +he runs in time like H to the m he needs + + align:start position:0% +he runs in time like H to the m he needs + + + align:start position:0% +he runs in time like H to the m he needs +to do all the sum he needs to run so the + + align:start position:0% +to do all the sum he needs to run so the + + + align:start position:0% +to do all the sum he needs to run so the +polinomial so it's called a t subf is + + align:start position:0% +polinomial so it's called a t subf is + + + align:start position:0% +polinomial so it's called a t subf is +the time to run uh to compute F so we + + align:start position:0% +the time to run uh to compute F so we + + + align:start position:0% +the time to run uh to compute F so we +need to compute F uh he needs to uh do + + align:start position:0% +need to compute F uh he needs to uh do + + + align:start position:0% +need to compute F uh he needs to uh do +the sum overall fs and he does that kind + + align:start position:0% +the sum overall fs and he does that kind + + + align:start position:0% +the sum overall fs and he does that kind +of a d m times right something like + + align:start position:0% + + + + align:start position:0% + +this A and polog H polog F + + align:start position:0% + + + + align:start position:0% + +sorry + + align:start position:0% +sorry + + + align:start position:0% +sorry +yeah so that's the pro ver test + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +yes no good good good good good great + + align:start position:0% +yes no good good good good good great + + + align:start position:0% +yes no good good good good good great +question no so you're okay so even if V + + align:start position:0% +question no so you're okay so even if V + + + align:start position:0% +question no so you're okay so even if V +has random Oracle access to F he can + + align:start position:0% +has random Oracle access to F he can + + + align:start position:0% +has random Oracle access to F he can +compute this entire thing but it will + + align:start position:0% +compute this entire thing but it will + + + align:start position:0% +compute this entire thing but it will +take him time H to the end because he + + align:start position:0% +take him time H to the end because he + + + align:start position:0% +take him time H to the end because he +needs to computer some so the the goal + + align:start position:0% +needs to computer some so the the goal + + + align:start position:0% +needs to computer some so the the goal +he needs to check so let's say Computing + + align:start position:0% +he needs to check so let's say Computing + + + align:start position:0% +he needs to check so let's say Computing +F once it takes the one time you can + + align:start position:0% +F once it takes the one time you can + + + align:start position:0% +F once it takes the one time you can +kind of ask but to check the sum he + + align:start position:0% +kind of ask but to check the sum he + + + align:start position:0% +kind of ask but to check the sum he +needs to + + align:start position:0% +needs to + + + align:start position:0% +needs to +ask this an H to the m question now + + align:start position:0% +ask this an H to the m question now + + + align:start position:0% +ask this an H to the m question now +think of H of them is + + align:start position:0% +think of H of them is + + + align:start position:0% +think of H of them is +huge even if a even if H is two think of + + align:start position:0% +huge even if a even if H is two think of + + + align:start position:0% +huge even if a even if H is two think of +M as being Big M is like n variable so + + align:start position:0% +M as being Big M is like n variable so + + + align:start position:0% +M as being Big M is like n variable so +it's like exponential that's it great + + align:start position:0% +it's like exponential that's it great + + + align:start position:0% +it's like exponential that's it great +question but should I think of the + + align:start position:0% +question but should I think of the + + + align:start position:0% +question but should I think of the +description of f Pol or good so you can + + align:start position:0% +description of f Pol or good so you can + + + align:start position:0% +description of f Pol or good so you can +okay there's two options you can think + + align:start position:0% +okay there's two options you can think + + + align:start position:0% +okay there's two options you can think +of the description of f as being + + align:start position:0% +of the description of f as being + + + align:start position:0% +of the description of f as being +polinomial that's one option or that you + + align:start position:0% +polinomial that's one option or that you + + + align:start position:0% +polinomial that's one option or that you +can compute F in it's like described by + + align:start position:0% +can compute F in it's like described by + + + align:start position:0% +can compute F in it's like described by +a polinomial size circuit or you can + + align:start position:0% +a polinomial size circuit or you can + + + align:start position:0% +a polinomial size circuit or you can +think it can be large but the verifier + + align:start position:0% +think it can be large but the verifier + + + align:start position:0% +think it can be large but the verifier +has access to it somehow the verifier + + align:start position:0% +has access to it somehow the verifier + + + align:start position:0% +has access to it somehow the verifier +has like a trusted Oracle that computes + + align:start position:0% +has like a trusted Oracle that computes + + + align:start position:0% +has like a trusted Oracle that computes +app for + + align:start position:0% +app for + + + align:start position:0% +app for +him + + align:start position:0% +him + + + align:start position:0% +him +okay great okay so now the + + align:start position:0% +okay great okay so now the + + + align:start position:0% +okay great okay so now the +so + + align:start position:0% +so + + + align:start position:0% +so +yes good yeah this is just sorry this + + align:start position:0% +yes good yeah this is just sorry this + + + align:start position:0% +yes good yeah this is just sorry this +it's just the time it takes to compute + + align:start position:0% + + + + align:start position:0% + +F thanks + + align:start position:0% +F thanks + + + align:start position:0% +F thanks +yeah because he needs to comp the + + align:start position:0% +yeah because he needs to comp the + + + align:start position:0% +yeah because he needs to comp the +approver supposedly doesn't have he + + align:start position:0% +approver supposedly doesn't have he + + + align:start position:0% +approver supposedly doesn't have he +needs to actually do the + + align:start position:0% + + + + align:start position:0% + +computation okay great yes um whereing + + align:start position:0% +computation okay great yes um whereing + + + align:start position:0% +computation okay great yes um whereing +that into account the theover finding G + + align:start position:0% +that into account the theover finding G + + + align:start position:0% +that into account the theover finding G +of One X like don't they have to combine + + align:start position:0% +of One X like don't they have to combine + + + align:start position:0% +of One X like don't they have to combine +a bunch of terms order of oh yeah but uh + + align:start position:0% +a bunch of terms order of oh yeah but uh + + + align:start position:0% +a bunch of terms order of oh yeah but uh +he runs in time F anyway f is much + + align:start position:0% +he runs in time F anyway f is much + + + align:start position:0% +he runs in time F anyway f is much +bigger than D so the degree is also + + align:start position:0% +bigger than D so the degree is also + + + align:start position:0% +bigger than D so the degree is also +always much smaller + + align:start position:0% +always much smaller + + + align:start position:0% +always much smaller +F so it's I'm kind of lumping it in yeah + + align:start position:0% +F so it's I'm kind of lumping it in yeah + + + align:start position:0% +F so it's I'm kind of lumping it in yeah +thanks great question + + align:start position:0% + + + + align:start position:0% + +yeah something else again you're saying + + align:start position:0% +yeah something else again you're saying + + + align:start position:0% +yeah something else again you're saying +if you you want to be even you you're + + align:start position:0% +if you you want to be even you you're + + + align:start position:0% +if you you want to be even you you're +saying let's say the verifier wants to + + align:start position:0% +saying let's say the verifier wants to + + + align:start position:0% +saying let's say the verifier wants to +be even more efficient than this then + + align:start position:0% +be even more efficient than this then + + + align:start position:0% +be even more efficient than this then +what can you do can I choose H to be + + align:start position:0% +what can you do can I choose H to be + + + align:start position:0% +what can you do can I choose H to be +like special structure okay but you're + + align:start position:0% +like special structure okay but you're + + + align:start position:0% +like special structure okay but you're +changing the problem you what you're + + align:start position:0% +changing the problem you what you're + + + align:start position:0% +changing the problem you what you're +saying is so the problem is H is given + + align:start position:0% +saying is so the problem is H is given + + + align:start position:0% +saying is so the problem is H is given +to us and you want to prove now you're + + align:start position:0% +to us and you want to prove now you're + + + align:start position:0% +to us and you want to prove now you're +saying maybe if H has a special + + align:start position:0% +saying maybe if H has a special + + + align:start position:0% +saying maybe if H has a special +structure maybe we can be even more + + align:start position:0% +structure maybe we can be even more + + + align:start position:0% +structure maybe we can be even more +efficient is what you're saying + + align:start position:0% +efficient is what you're saying + + + align:start position:0% +efficient is what you're saying +a good question a I haven't thought + + align:start position:0% +a good question a I haven't thought + + + align:start position:0% +a good question a I haven't thought +about + + align:start position:0% +about + + + align:start position:0% +about +itation yeah like you can probably uh + + align:start position:0% +itation yeah like you can probably uh + + + align:start position:0% +itation yeah like you can probably uh +yeah yeah probably you can you can so V + + align:start position:0% +yeah yeah probably you can you can so V + + + align:start position:0% +yeah yeah probably you can you can so V +not was saying you can probably batch + + align:start position:0% +not was saying you can probably batch + + + align:start position:0% +not was saying you can probably batch +things or probably yeah I think if you + + align:start position:0% +things or probably yeah I think if you + + + align:start position:0% +things or probably yeah I think if you +can choose H if H is of a certain + + align:start position:0% +can choose H if H is of a certain + + + align:start position:0% +can choose H if H is of a certain +structure then I think you can do better + + align:start position:0% +structure then I think you can do better + + + align:start position:0% +structure then I think you can do better +but this is kind of your the verifier + + align:start position:0% +but this is kind of your the verifier + + + align:start position:0% +but this is kind of your the verifier +doesn't choose it like that's what's + + align:start position:0% +doesn't choose it like that's what's + + + align:start position:0% +doesn't choose it like that's what's +given them great okay + + align:start position:0% +given them great okay + + + align:start position:0% +given them great okay +great okay any more any more a + + align:start position:0% +great okay any more any more a + + + align:start position:0% +great okay any more any more a +questions + + align:start position:0% + + + + align:start position:0% + +yeah oh okay it's degree D but it's m + + align:start position:0% +yeah oh okay it's degree D but it's m + + + align:start position:0% +yeah oh okay it's degree D but it's m +variables so in General Degree D + + align:start position:0% +variables so in General Degree D + + + align:start position:0% +variables so in General Degree D +polinomial with m variables can have + + align:start position:0% +polinomial with m variables can have + + + align:start position:0% +polinomial with m variables can have +size like m to the D so which is can be + + align:start position:0% +size like m to the D so which is can be + + + align:start position:0% +size like m to the D so which is can be +very big great question a d to the m + + align:start position:0% +very big great question a d to the m + + + align:start position:0% +very big great question a d to the m +sorry yeah great great + + align:start position:0% + + + + align:start position:0% + +question okay okay so let's go to + + align:start position:0% +question okay okay so let's go to + + + align:start position:0% +question okay okay so let's go to +completeness and soundness then so what + + align:start position:0% +completeness and soundness then so what + + + align:start position:0% +completeness and soundness then so what +is the completeness of this protocol if + + align:start position:0% +is the completeness of this protocol if + + + align:start position:0% +is the completeness of this protocol if +let's say the pro is honest the + + align:start position:0% +let's say the pro is honest the + + + align:start position:0% +let's say the pro is honest the +statement is correct with what + + align:start position:0% +statement is correct with what + + + align:start position:0% +statement is correct with what +probability will the verifier + + align:start position:0% +probability will the verifier + + + align:start position:0% +probability will the verifier +accept one exactly because you'll just + + align:start position:0% +accept one exactly because you'll just + + + align:start position:0% +accept one exactly because you'll just +be honest you always give the C nomial + + align:start position:0% +be honest you always give the C nomial + + + align:start position:0% +be honest you always give the C nomial +always be Lo degree will always sum to + + align:start position:0% +always be Lo degree will always sum to + + + align:start position:0% +always be Lo degree will always sum to +what it should be and you always going + + align:start position:0% +what it should be and you always going + + + align:start position:0% +what it should be and you always going +accept it that's easy the hard part is + + align:start position:0% +accept it that's easy the hard part is + + + align:start position:0% +accept it that's easy the hard part is +soundness so let's do the soundness and + + align:start position:0% +soundness so let's do the soundness and + + + align:start position:0% +soundness so let's do the soundness and +then after soundness we'll take + + align:start position:0% + + + + align:start position:0% + +a okay so for sound this here's the idea + + align:start position:0% +a okay so for sound this here's the idea + + + align:start position:0% +a okay so for sound this here's the idea +suppose so let's look at it fix suppose + + align:start position:0% +suppose so let's look at it fix suppose + + + align:start position:0% +suppose so let's look at it fix suppose +there's a cheating + + align:start position:0% +there's a cheating + + + align:start position:0% +there's a cheating +prover that generates a false clip so + + align:start position:0% +prover that generates a false clip so + + + align:start position:0% +prover that generates a false clip so +suppose + + align:start position:0% + + + + align:start position:0% + +that the claim is + + align:start position:0% + + + + align:start position:0% + +false mainly this sum of + + align:start position:0% + + + + align:start position:0% + +f is actually not + + align:start position:0% + + + + align:start position:0% + +big okay so we start with the false CL + + align:start position:0% +big okay so we start with the false CL + + + align:start position:0% +big okay so we start with the false CL +the first thing we know is that and so + + align:start position:0% +the first thing we know is that and so + + + align:start position:0% +the first thing we know is that and so +fix any so you you fix a claim that's + + align:start position:0% +fix any so you you fix a claim that's + + + align:start position:0% +fix any so you you fix a claim that's +false fix any piece + + align:start position:0% +false fix any piece + + + align:start position:0% +false fix any piece +he tries to cheat let's show that he he + + align:start position:0% +he tries to cheat let's show that he he + + + align:start position:0% +he tries to cheat let's show that he he +fails like he won't succeed or succeed + + align:start position:0% +fails like he won't succeed or succeed + + + align:start position:0% +fails like he won't succeed or succeed +very small probability the field is + + align:start position:0% +very small probability the field is + + + align:start position:0% +very small probability the field is +large enough so let's + + align:start position:0% +large enough so let's + + + align:start position:0% +large enough so let's +see first the first thing I want to + + align:start position:0% +see first the first thing I want to + + + align:start position:0% +see first the first thing I want to +point out which I mentioned before is G1 + + align:start position:0% +point out which I mentioned before is G1 + + + align:start position:0% +point out which I mentioned before is G1 +must be false G so it must be the case + + align:start position:0% +must be false G so it must be the case + + + align:start position:0% +must be false G so it must be the case +no matter how he cheats and he gives me + + align:start position:0% +no matter how he cheats and he gives me + + + align:start position:0% +no matter how he cheats and he gives me +a bad G1 okay it cannot if he's accepted + + align:start position:0% +a bad G1 okay it cannot if he's accepted + + + align:start position:0% +a bad G1 okay it cannot if he's accepted +if the Prov is accepted then G1 cannot + + align:start position:0% +if the Prov is accepted then G1 cannot + + + align:start position:0% +if the Prov is accepted then G1 cannot +be sum of + + align:start position:0% +be sum of + + + align:start position:0% +be sum of +a call + + align:start position:0% +a call + + + align:start position:0% +a call +g1x is not sum of f H2 up to + + align:start position:0% +g1x is not sum of f H2 up to + + + align:start position:0% +g1x is not sum of f H2 up to +hm because I'm going to check that it's + + align:start position:0% +hm because I'm going to check that it's + + + align:start position:0% +hm because I'm going to check that it's +equal to Beta but the sum of f is not + + align:start position:0% +equal to Beta but the sum of f is not + + + align:start position:0% +equal to Beta but the sum of f is not +beta so the G that he gives me cannot be + + align:start position:0% +beta so the G that he gives me cannot be + + + align:start position:0% +beta so the G that he gives me cannot be +the correct F like the correct + + align:start position:0% + + + + align:start position:0% + +G okay so in other words he starts the + + align:start position:0% +G okay so in other words he starts the + + + align:start position:0% +G okay so in other words he starts the +protocol by a cheat a the first message + + align:start position:0% +protocol by a cheat a the first message + + + align:start position:0% +protocol by a cheat a the first message +is not the correct + + align:start position:0% +is not the correct + + + align:start position:0% +is not the correct +polinomial okay because the correct + + align:start position:0% +polinomial okay because the correct + + + align:start position:0% +polinomial okay because the correct +polinomial if you Summit you'll get the + + align:start position:0% +polinomial if you Summit you'll get the + + + align:start position:0% +polinomial if you Summit you'll get the +real beta not the fake + + align:start position:0% +real beta not the fake + + + align:start position:0% +real beta not the fake +beta okay that he + + align:start position:0% +beta okay that he + + + align:start position:0% +beta okay that he +claimed okay however at the end of the + + align:start position:0% +claimed okay however at the end of the + + + align:start position:0% +claimed okay however at the end of the +day if you're + + align:start position:0% +day if you're + + + align:start position:0% +day if you're +accepted the final check when you check + + align:start position:0% +accepted the final check when you check + + + align:start position:0% +accepted the final check when you check +then you check with respect to the + + align:start position:0% +then you check with respect to the + + + align:start position:0% +then you check with respect to the +honest F right and that verifies so at + + align:start position:0% +honest F right and that verifies so at + + + align:start position:0% +honest F right and that verifies so at +the end of the day when you left with G + + align:start position:0% +the end of the day when you left with G + + + align:start position:0% +the end of the day when you left with G +to the like the last one GM to the TM + + align:start position:0% +to the like the last one GM to the TM + + + align:start position:0% +to the like the last one GM to the TM +that's actually + + align:start position:0% +that's actually + + + align:start position:0% +that's actually +honest so somewh the protocol you had to + + align:start position:0% +honest so somewh the protocol you had to + + + align:start position:0% +honest so somewh the protocol you had to +move from a + + align:start position:0% +move from a + + + align:start position:0% +move from a +bad G to a good + + align:start position:0% + + + + align:start position:0% + +G okay so again here's the + + align:start position:0% +G okay so again here's the + + + align:start position:0% +G okay so again here's the +claim so I want to argue if so let there + + align:start position:0% +claim so I want to argue if so let there + + + align:start position:0% +claim so I want to argue if so let there +I want to argue there must exist a round + + align:start position:0% +I want to argue there must exist a round + + + align:start position:0% +I want to argue there must exist a round +such that around let's say I so to Pro + + align:start position:0% +such that around let's say I so to Pro + + + align:start position:0% +such that around let's say I so to Pro +to cheat + + align:start position:0% + + + + align:start position:0% + +there must exist around + + align:start position:0% + + + + align:start position:0% + +I such + + align:start position:0% +I such + + + align:start position:0% +I such +that + + align:start position:0% +that + + + align:start position:0% +that +GI is false so GI is not sum of + + align:start position:0% +GI is false so GI is not sum of + + + align:start position:0% +GI is false so GI is not sum of +T1 t i-1 x h i +1 up to hm this is what + + align:start position:0% +T1 t i-1 x h i +1 up to hm this is what + + + align:start position:0% +T1 t i-1 x h i +1 up to hm this is what +it should be but it's not + + align:start position:0% + + + + align:start position:0% + +and yet at some point but g i + + + align:start position:0% + + + + align:start position:0% + +one is actually equal to oh I forgot + + align:start position:0% +one is actually equal to oh I forgot + + + align:start position:0% +one is actually equal to oh I forgot +f is actually equal to some f T1 up to + + align:start position:0% + + + + align:start position:0% + +ti so to cheat you must go so you start + + align:start position:0% +ti so to cheat you must go so you start + + + align:start position:0% +ti so to cheat you must go so you start +with with you start with an + + align:start position:0% +with with you start with an + + + align:start position:0% +with with you start with an +incorrect A A polom we know that's for + + align:start position:0% +incorrect A A polom we know that's for + + + align:start position:0% +incorrect A A polom we know that's for +sure because you assuming you're you're + + align:start position:0% +sure because you assuming you're you're + + + align:start position:0% +sure because you assuming you're you're +accepted if you're accepted G1 is false + + align:start position:0% +accepted if you're accepted G1 is false + + + align:start position:0% +accepted if you're accepted G1 is false +now either now G2 is true and then I'll + + align:start position:0% +now either now G2 is true and then I'll + + + align:start position:0% +now either now G2 is true and then I'll +show that happens with very small + + align:start position:0% +show that happens with very small + + + align:start position:0% +show that happens with very small +probability or G2 is also false if G2 is + + align:start position:0% +probability or G2 is also false if G2 is + + + align:start position:0% +probability or G2 is also false if G2 is +false I G3 is true I'm going to show + + align:start position:0% +false I G3 is true I'm going to show + + + align:start position:0% +false I G3 is true I'm going to show +that happens with very small probability + + align:start position:0% +that happens with very small probability + + + align:start position:0% +that happens with very small probability +or G or G3 is false until we're left + + align:start position:0% +or G or G3 is false until we're left + + + align:start position:0% +or G or G3 is false until we're left +with + + align:start position:0% +with + + + align:start position:0% +with +GM which again let but it's still I'm + + align:start position:0% +GM which again let but it's still I'm + + + align:start position:0% +GM which again let but it's still I'm +going to argue that if G minus one was + + align:start position:0% +going to argue that if G minus one was + + + align:start position:0% +going to argue that if G minus one was +false GM is also false with very high + + align:start position:0% +false GM is also false with very high + + + align:start position:0% +false GM is also false with very high +probability but if GM is + + align:start position:0% +probability but if GM is + + + align:start position:0% +probability but if GM is +false you're not going to be if GM is + + align:start position:0% +false you're not going to be if GM is + + + align:start position:0% +false you're not going to be if GM is +actually not + + align:start position:0% +actually not + + + align:start position:0% +actually not +F then for random T the probability that + + align:start position:0% +F then for random T the probability that + + + align:start position:0% +F then for random T the probability that +you'll get f is very very you'll be + + align:start position:0% +you'll get f is very very you'll be + + + align:start position:0% +you'll get f is very very you'll be +consistent with f is very very small + + align:start position:0% +consistent with f is very very small + + + align:start position:0% +consistent with f is very very small +because these are two different + + align:start position:0% +because these are two different + + + align:start position:0% +because these are two different +polinomial and they agree only on D + + align:start position:0% +polinomial and they agree only on D + + + align:start position:0% +polinomial and they agree only on D +points so what's the probability that I + + align:start position:0% +points so what's the probability that I + + + align:start position:0% +points so what's the probability that I +chose one of these D's one of these + + align:start position:0% +chose one of these D's one of these + + + align:start position:0% +chose one of these D's one of these +points D over f + + align:start position:0% +points D over f + + + align:start position:0% +points D over f +okay so let me let me be a little more + + align:start position:0% +okay so let me let me be a little more + + + align:start position:0% +okay so let me let me be a little more +formal + + align:start position:0% +formal + + + align:start position:0% +formal +now okay so I want to argue that part me + + align:start position:0% +now okay so I want to argue that part me + + + align:start position:0% +now okay so I want to argue that part me +argue that so first to cheat there must + + align:start position:0% +argue that so first to cheat there must + + + align:start position:0% +argue that so first to cheat there must +exist some round where we go from F from + + align:start position:0% +exist some round where we go from F from + + + align:start position:0% +exist some round where we go from F from +from false to true because the final + + align:start position:0% +from false to true because the final + + + align:start position:0% +from false to true because the final +final check must be true otherwise + + align:start position:0% +final check must be true otherwise + + + align:start position:0% +final check must be true otherwise +you're I'm going to check you with the + + align:start position:0% +you're I'm going to check you with the + + + align:start position:0% +you're I'm going to check you with the +true so there must exist a around that + + align:start position:0% +true so there must exist a around that + + + align:start position:0% +true so there must exist a around that +you go from false to True let's see + + align:start position:0% +you go from false to True let's see + + + align:start position:0% +you go from false to True let's see +what's the probability of going from + + align:start position:0% +what's the probability of going from + + + align:start position:0% +what's the probability of going from +false to true + + align:start position:0% + + + + align:start position:0% + +so good so what's the probability so + + align:start position:0% +so good so what's the probability so + + + align:start position:0% +so good so what's the probability so +let's denote this event let's knowe this + + align:start position:0% +let's denote this event let's knowe this + + + align:start position:0% +let's denote this event let's knowe this +event by + + align:start position:0% +event by + + + align:start position:0% +event by +bi now let's see what's the probability + + align:start position:0% +bi now let's see what's the probability + + + align:start position:0% +bi now let's see what's the probability +that this events happen this is kind of + + align:start position:0% +that this events happen this is kind of + + + align:start position:0% +that this events happen this is kind of +a bad event an event that you go from a + + align:start position:0% +a bad event an event that you go from a + + + align:start position:0% +a bad event an event that you go from a +bad incorrect a false to true that's for + + align:start position:0% +bad incorrect a false to true that's for + + + align:start position:0% +bad incorrect a false to true that's for +the ver part it's a very bad event + + align:start position:0% +the ver part it's a very bad event + + + align:start position:0% +the ver part it's a very bad event +because then he accepts a false + + align:start position:0% +because then he accepts a false + + + align:start position:0% +because then he accepts a false +statement what is the probability that + + align:start position:0% +statement what is the probability that + + + align:start position:0% +statement what is the probability that +this bad event happen so the + + align:start position:0% +this bad event happen so the + + + align:start position:0% +this bad event happen so the +probability of + + align:start position:0% +probability of + + + align:start position:0% +probability of +B I want to argue is that + + align:start position:0% + + + + align:start position:0% + +most D over F let's see + + align:start position:0% +most D over F let's see + + + align:start position:0% +most D over F let's see +why + + align:start position:0% +why + + + align:start position:0% +why +so when is let's see when is GI + one + + align:start position:0% +so when is let's see when is GI + one + + + align:start position:0% +so when is let's see when is GI + one +true we're sending here like the very + + align:start position:0% +true we're sending here like the very + + + align:start position:0% +true we're sending here like the very +the probability let's fix like we fixed + + align:start position:0% +the probability let's fix like we fixed + + + align:start position:0% +the probability let's fix like we fixed +already T1 of the ti plus1 that's fixed + + align:start position:0% +already T1 of the ti plus1 that's fixed + + + align:start position:0% +already T1 of the ti plus1 that's fixed +okay so fix and I don't care how t one + + align:start position:0% +okay so fix and I don't care how t one + + + align:start position:0% +okay so fix and I don't care how t one +up to t i minus one this + + align:start position:0% + + + + align:start position:0% + +defines like the what the prover + + align:start position:0% +defines like the what the prover + + + align:start position:0% +defines like the what the prover +gives GI in the protocol the cheating + + align:start position:0% +gives GI in the protocol the cheating + + + align:start position:0% +gives GI in the protocol the cheating +prover gives in the + + align:start position:0% +prover gives in the + + + align:start position:0% +prover gives in the +protocol okay + + align:start position:0% +protocol okay + + + align:start position:0% +protocol okay +now now the verifier chooses a random t + + align:start position:0% +now now the verifier chooses a random t + + + align:start position:0% +now now the verifier chooses a random t +a random uh so good so this defines GI + + align:start position:0% +a random uh so good so this defines GI + + + align:start position:0% +a random uh so good so this defines GI +which is uh okay this is my G now the + + align:start position:0% +which is uh okay this is my G now the + + + align:start position:0% +which is uh okay this is my G now the +prover the verifier the probability over + + align:start position:0% +prover the verifier the probability over + + + align:start position:0% +prover the verifier the probability over +TI that the verifier + + align:start position:0% + + + + align:start position:0% + +chooses This Ti tells you if GI this + + align:start position:0% +chooses This Ti tells you if GI this + + + align:start position:0% +chooses This Ti tells you if GI this +defines GI + + + align:start position:0% +defines GI + + + + align:start position:0% +defines GI + +one but when it's + + align:start position:0% +one but when it's + + + align:start position:0% +one but when it's +if what do we know about when + + align:start position:0% + + + + align:start position:0% + +if we know that because the verifier is + + align:start position:0% +if we know that because the verifier is + + + align:start position:0% +if we know that because the verifier is +accepted we know that some g i +1 of + + align:start position:0% + + + + align:start position:0% + +H is equal to + + align:start position:0% +H is equal to + + + align:start position:0% +H is equal to +GI which is the wrong + + align:start position:0% + + + + align:start position:0% + +polinomial + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% + + + + align:start position:0% + +uh sorry + + align:start position:0% + + + + align:start position:0% + +NTI and this is the wrong polinomial so + + align:start position:0% +NTI and this is the wrong polinomial so + + + align:start position:0% +NTI and this is the wrong polinomial so +what is the probability that for so so + + align:start position:0% +what is the probability that for so so + + + align:start position:0% +what is the probability that for so so +in other words J + one is the wrong + + align:start position:0% +in other words J + one is the wrong + + + align:start position:0% +in other words J + one is the wrong +polom + + align:start position:0% +polom + + + align:start position:0% +polom +what is the probability that for a + + align:start position:0% +what is the probability that for a + + + align:start position:0% +what is the probability that for a +random T it will be the right + + align:start position:0% +random T it will be the right + + + align:start position:0% +random T it will be the right +one D over + + align:start position:0% + + + + align:start position:0% + +F because two polinomial that are + + align:start position:0% +F because two polinomial that are + + + align:start position:0% +F because two polinomial that are +different agree on it most D points I + + align:start position:0% +different agree on it most D points I + + + align:start position:0% +different agree on it most D points I +chose a random point the probability + + align:start position:0% +chose a random point the probability + + + align:start position:0% +chose a random point the probability +that it's one of these D is D over + + align:start position:0% +that it's one of these D is D over + + + align:start position:0% +that it's one of these D is D over +F so what is the probability that you + + align:start position:0% + + + + align:start position:0% + +cheat at this is the + + align:start position:0% +cheat at this is the + + + align:start position:0% +cheat at this is the +probability that there exist some + + align:start position:0% +probability that there exist some + + + align:start position:0% +probability that there exist some +I such that bi holds a bad event holds + + align:start position:0% +I such that bi holds a bad event holds + + + align:start position:0% +I such that bi holds a bad event holds +namely there exists an eye that you go + + align:start position:0% +namely there exists an eye that you go + + + align:start position:0% +namely there exists an eye that you go +from True from false to + + align:start position:0% +from True from false to + + + align:start position:0% +from True from false to +true and that IE by the union bound this + + align:start position:0% +true and that IE by the union bound this + + + align:start position:0% +true and that IE by the union bound this +is at most M number of rounds Times the + + align:start position:0% +is at most M number of rounds Times the + + + align:start position:0% +is at most M number of rounds Times the +probability of one of a specific b b me + + align:start position:0% +probability of one of a specific b b me + + + align:start position:0% +probability of one of a specific b b me +which is D over + + align:start position:0% +which is D over + + + align:start position:0% +which is D over +F so just just note H actually doesn't + + align:start position:0% +F so just just note H actually doesn't + + + align:start position:0% +F so just just note H actually doesn't +come + + align:start position:0% +come + + + align:start position:0% +come +up in the soundness this is the + + align:start position:0% + + + + align:start position:0% + +soundness okay so the sinus needs M time + + align:start position:0% +soundness okay so the sinus needs M time + + + align:start position:0% +soundness okay so the sinus needs M time +D to be significantly smaller than the + + align:start position:0% +D to be significantly smaller than the + + + align:start position:0% +D to be significantly smaller than the +field + + align:start position:0% +field + + + align:start position:0% +field +size that's all that's important for + + align:start position:0% +size that's all that's important for + + + align:start position:0% +size that's all that's important for +sence yeah so Point like + + align:start position:0% +sence yeah so Point like + + + align:start position:0% +sence yeah so Point like +the + + align:start position:0% + + + + align:start position:0% + +have exact exactly the point is if + + align:start position:0% +have exact exactly the point is if + + + align:start position:0% +have exact exactly the point is if +you're not happy if f is not large + + align:start position:0% +you're not happy if f is not large + + + align:start position:0% +you're not happy if f is not large +enough if it's not much bigger than m + + align:start position:0% +enough if it's not much bigger than m + + + align:start position:0% +enough if it's not much bigger than m +the m * D then you just make it bigger + + align:start position:0% +the m * D then you just make it bigger + + + align:start position:0% +the m * D then you just make it bigger +you can take you can take extension + + align:start position:0% +you can take you can take extension + + + align:start position:0% +you can take you can take extension +Fields you can take so you just kind of + + align:start position:0% +Fields you can take so you just kind of + + + align:start position:0% +Fields you can take so you just kind of +artificially increase F so that F will + + align:start position:0% +artificially increase F so that F will + + + align:start position:0% +artificially increase F so that F will +be much larger than M * D and hence + + align:start position:0% +be much larger than M * D and hence + + + align:start position:0% +be much larger than M * D and hence +you'll get a small + + align:start position:0% + + + + align:start position:0% + +s + + align:start position:0% +s + + + align:start position:0% +s +applications what happens is given H + + align:start position:0% +applications what happens is given H + + + align:start position:0% +applications what happens is given H +right and the degree happens to be uh H + + align:start position:0% +right and the degree happens to be uh H + + + align:start position:0% +right and the degree happens to be uh H +ESS or h that's why it doesn't make + + align:start position:0% +ESS or h that's why it doesn't make + + + align:start position:0% +ESS or h that's why it doesn't make +sense for H and to be the same but you + + align:start position:0% +sense for H and to be the same but you + + + align:start position:0% +sense for H and to be the same but you +can dis exactly can dis 100% so let me + + align:start position:0% +can dis exactly can dis 100% so let me + + + align:start position:0% +can dis exactly can dis 100% so let me +repeat it because I'm recorded you're + + align:start position:0% +repeat it because I'm recorded you're + + + align:start position:0% +repeat it because I'm recorded you're +not yeah because that's a very good + + align:start position:0% +not yeah because that's a very good + + + align:start position:0% +not yeah because that's a very good +point the the point is for Su in general + + align:start position:0% +point the the point is for Su in general + + + align:start position:0% +point the the point is for Su in general +it makes sense to consider any ag even H + + align:start position:0% +it makes sense to consider any ag even H + + + align:start position:0% +it makes sense to consider any ag even H +which is of size f is interesting for + + align:start position:0% +which is of size f is interesting for + + + align:start position:0% +which is of size f is interesting for +the Su protocol okay in application + + align:start position:0% +the Su protocol okay in application + + + align:start position:0% +the Su protocol okay in application +because as long as the D is small of + + align:start position:0% +because as long as the D is small of + + + align:start position:0% +because as long as the D is small of +course in applications often it turns + + align:start position:0% +course in applications often it turns + + + align:start position:0% +course in applications often it turns +out that the when we use the sub check + + align:start position:0% +out that the when we use the sub check + + + align:start position:0% +out that the when we use the sub check +it turns out that the D is often equal + + align:start position:0% +it turns out that the D is often equal + + + align:start position:0% +it turns out that the D is often equal +to the size of + + align:start position:0% +to the size of + + + align:start position:0% +to the size of +H okay because we kind of do the slow + + align:start position:0% +H okay because we kind of do the slow + + + align:start position:0% +H okay because we kind of do the slow +degree extension which makes the field + + align:start position:0% +degree extension which makes the field + + + align:start position:0% +degree extension which makes the field +as large as + + align:start position:0% +as large as + + + align:start position:0% +as large as +H and then if a if if we take H which + + align:start position:0% +H and then if a if if we take H which + + + align:start position:0% +H and then if a if if we take H which +becomes the degree to be F this is + + align:start position:0% +becomes the degree to be F this is + + + align:start position:0% +becomes the degree to be F this is +Meaningful + + align:start position:0% +Meaningful + + + align:start position:0% +Meaningful +meaningless so for + + align:start position:0% +meaningless so for + + + align:start position:0% +meaningless so for +application often indeed H is small but + + align:start position:0% +application often indeed H is small but + + + align:start position:0% +application often indeed H is small but +for the sum of prot it's own you can + + align:start position:0% +for the sum of prot it's own you can + + + align:start position:0% +for the sum of prot it's own you can +make you can take eight to be the entire + + align:start position:0% +make you can take eight to be the entire + + + align:start position:0% +make you can take eight to be the entire +field yes is it that find F like it's + + align:start position:0% +field yes is it that find F like it's + + + align:start position:0% +field yes is it that find F like it's +easy to put another yeah okay good good + + align:start position:0% +easy to put another yeah okay good good + + + align:start position:0% +easy to put another yeah okay good good +good yes exactly so let me yeah so it + + align:start position:0% +good yes exactly so let me yeah so it + + + align:start position:0% +good yes exactly so let me yeah so it +there's kind of uh you can take so this + + align:start position:0% +there's kind of uh you can take so this + + + align:start position:0% +there's kind of uh you can take so this +is a fact from mathematics you can take + + align:start position:0% +is a fact from mathematics you can take + + + align:start position:0% +is a fact from mathematics you can take +any finite field and embed it into a + + align:start position:0% +any finite field and embed it into a + + + align:start position:0% +any finite field and embed it into a +bigger finite field and how big is the + + align:start position:0% +bigger finite field and how big is the + + + align:start position:0% +bigger finite field and how big is the +bigger finite field kind of as big as + + align:start position:0% +bigger finite field kind of as big as + + + align:start position:0% +bigger finite field kind of as big as +you want so you can take any Loosely + + align:start position:0% +you want so you can take any Loosely + + + align:start position:0% +you want so you can take any Loosely +speaking you can take any F and embed it + + align:start position:0% +speaking you can take any F and embed it + + + align:start position:0% +speaking you can take any F and embed it +into kind of a field F to the + + align:start position:0% +into kind of a field F to the + + + align:start position:0% +into kind of a field F to the +N uh so when you can take n as big as + + align:start position:0% +N uh so when you can take n as big as + + + align:start position:0% +N uh so when you can take n as big as +you want so you can kind of that's + + align:start position:0% +you want so you can kind of that's + + + align:start position:0% +you want so you can kind of that's +what's called an extension + + align:start position:0% +what's called an extension + + + align:start position:0% +what's called an extension +field so you can kind of extend it to as + + align:start position:0% +field so you can kind of extend it to as + + + align:start position:0% +field so you can kind of extend it to as +large size as you want while still + + align:start position:0% +large size as you want while still + + + align:start position:0% +large size as you want while still +keeping f as a sub field so operations + + align:start position:0% +keeping f as a sub field so operations + + + align:start position:0% +keeping f as a sub field so operations +in F kind of behave exactly as they did + + align:start position:0% +in F kind of behave exactly as they did + + + align:start position:0% +in F kind of behave exactly as they did +before so without ruing the sum or + + align:start position:0% +before so without ruing the sum or + + + align:start position:0% +before so without ruing the sum or +anything like + + align:start position:0% +anything like + + + align:start position:0% +anything like +that this Anis right is it really the + + align:start position:0% +that this Anis right is it really the + + + align:start position:0% +that this Anis right is it really the +case that there is actually a chea + + align:start position:0% +case that there is actually a chea + + + align:start position:0% +case that there is actually a chea +strategy that succeeds with yes this + + align:start position:0% +strategy that succeeds with yes this + + + align:start position:0% +strategy that succeeds with yes this +yeah this good this analysis is really + + align:start position:0% +yeah this good this analysis is really + + + align:start position:0% +yeah this good this analysis is really +tight so I mean if if I'm malicious you + + align:start position:0% +tight so I mean if if I'm malicious you + + + align:start position:0% +tight so I mean if if I'm malicious you +know I can always hope for the best if + + align:start position:0% +know I can always hope for the best if + + + align:start position:0% +know I can always hope for the best if +it happens to be I'm malicious I give + + align:start position:0% +it happens to be I'm malicious I give + + + align:start position:0% +it happens to be I'm malicious I give +you the wrong polinomial look you may + + align:start position:0% +you the wrong polinomial look you may + + + align:start position:0% +you the wrong polinomial look you may +find so I want to go from the wrong Pol + + align:start position:0% +find so I want to go from the wrong Pol + + + align:start position:0% +find so I want to go from the wrong Pol +to the true polinomial that's what to + + align:start position:0% +to the true polinomial that's what to + + + align:start position:0% +to the true polinomial that's what to +cheat right that's what I want to do now + + align:start position:0% +cheat right that's what I want to do now + + + align:start position:0% +cheat right that's what I want to do now +the the my wrong poal and the true + + align:start position:0% +the the my wrong poal and the true + + + align:start position:0% +the the my wrong poal and the true +polinomial they agree the points any two + + align:start position:0% +polinomial they agree the points any two + + + align:start position:0% +polinomial they agree the points any two +pomal can agree on the points so as long + + align:start position:0% +pomal can agree on the points so as long + + + align:start position:0% +pomal can agree on the points so as long +as the verifier I'm lucky enough that + + align:start position:0% +as the verifier I'm lucky enough that + + + align:start position:0% +as the verifier I'm lucky enough that +this T is one of the deep points I mean + + align:start position:0% +this T is one of the deep points I mean + + + align:start position:0% +this T is one of the deep points I mean +look I got a good pomal I'll continue + + align:start position:0% +look I got a good pomal I'll continue + + + align:start position:0% +look I got a good pomal I'll continue +with a good pomal till the end of now + + align:start position:0% +with a good pomal till the end of now + + + align:start position:0% +with a good pomal till the end of now +I'm I'm in kind of a h La La Land you + + align:start position:0% +I'm I'm in kind of a h La La Land you + + + align:start position:0% +I'm I'm in kind of a h La La Land you +know I'm happy uh the problem is the + + align:start position:0% +know I'm happy uh the problem is the + + + align:start position:0% +know I'm happy uh the problem is the +chance each one the chance that you'll + + align:start position:0% +chance each one the chance that you'll + + + align:start position:0% +chance each one the chance that you'll +give me a t that's one of the D points + + align:start position:0% +give me a t that's one of the D points + + + align:start position:0% +give me a t that's one of the D points +is only D over F and a union bound over + + align:start position:0% +is only D over F and a union bound over + + + align:start position:0% +is only D over F and a union bound over +everything it's n times D over F and if + + align:start position:0% +everything it's n times D over F and if + + + align:start position:0% +everything it's n times D over F and if +f is much much bigger than n times D + + align:start position:0% +f is much much bigger than n times D + + + align:start position:0% +f is much much bigger than n times D +then you know uh the chances that the + + align:start position:0% +then you know uh the chances that the + + + align:start position:0% +then you know uh the chances that the +Prov will Su will be in this L land is + + align:start position:0% +Prov will Su will be in this L land is + + + align:start position:0% +Prov will Su will be in this L land is +very small + + align:start position:0% + + + + align:start position:0% + +okay any any questions further questions + + align:start position:0% +okay any any questions further questions + + + align:start position:0% +okay any any questions further questions +about the subject + + align:start position:0% + + + + align:start position:0% + +protocol okay so let's take maybe kind + + align:start position:0% +protocol okay so let's take maybe kind + + + align:start position:0% +protocol okay so let's take maybe kind +of a five minute break to stretch and so + + align:start position:0% +of a five minute break to stretch and so + + + align:start position:0% +of a five minute break to stretch and so +on and then we'll show application we'll + + align:start position:0% +on and then we'll show application we'll + + + align:start position:0% +on and then we'll show application we'll +start showing applications for this \ No newline at end of file diff --git a/jJvVmdkiD3Y.txt b/jJvVmdkiD3Y.txt new file mode 100644 index 0000000000000000000000000000000000000000..1b1d87ac73548ef96abcd1cca514f1840b8815b9 --- /dev/null +++ b/jJvVmdkiD3Y.txt @@ -0,0 +1,11467 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT open courseware continue + + align:start position:0% +will help MIT open courseware continue + + + align:start position:0% +will help MIT open courseware continue +to offer highquality educational + + align:start position:0% +to offer highquality educational + + + align:start position:0% +to offer highquality educational +resources for free to make a donation or + + align:start position:0% +resources for free to make a donation or + + + align:start position:0% +resources for free to make a donation or +view additional materials from hundreds + + align:start position:0% +view additional materials from hundreds + + + align:start position:0% +view additional materials from hundreds +of MIT courses visit mitop courseware at + + align:start position:0% + + + + align:start position:0% + +ocw.mit.edu okay so I should probably + + align:start position:0% +ocw.mit.edu okay so I should probably + + + align:start position:0% +ocw.mit.edu okay so I should probably +get started um so I just wanted to + + align:start position:0% +get started um so I just wanted to + + + align:start position:0% +get started um so I just wanted to +mentioned this Friday the libraries are + + align:start position:0% +mentioned this Friday the libraries are + + + align:start position:0% +mentioned this Friday the libraries are +having furry Friday so you know they + + align:start position:0% +having furry Friday so you know they + + + align:start position:0% +having furry Friday so you know they +have therapy dogs come and if you like + + align:start position:0% +have therapy dogs come and if you like + + + align:start position:0% +have therapy dogs come and if you like +dogs it's kind of fun to go get cuddled + + align:start position:0% +dogs it's kind of fun to go get cuddled + + + align:start position:0% +dogs it's kind of fun to go get cuddled +by the dog the other thing I wanted to + + align:start position:0% +by the dog the other thing I wanted to + + + align:start position:0% +by the dog the other thing I wanted to +mention um you know last term there was + + align:start position:0% +mention um you know last term there was + + + align:start position:0% +mention um you know last term there was +a student taking 3032 who was interested + + align:start position:0% +a student taking 3032 who was interested + + + align:start position:0% +a student taking 3032 who was interested +in art and I kept trying to find art + + align:start position:0% +in art and I kept trying to find art + + + align:start position:0% +in art and I kept trying to find art +pictures for him and he's not here but I + + align:start position:0% +pictures for him and he's not here but I + + + align:start position:0% +pictures for him and he's not here but I +thought everybody else kind of liked the + + align:start position:0% +thought everybody else kind of liked the + + + align:start position:0% +thought everybody else kind of liked the +art too so I belong to the Peabody Essex + + align:start position:0% +art too so I belong to the Peabody Essex + + + align:start position:0% +art too so I belong to the Peabody Essex +Museum in Salem Mass and they have an + + align:start position:0% +Museum in Salem Mass and they have an + + + align:start position:0% +Museum in Salem Mass and they have an +exhibit right now on wood and on sort of + + align:start position:0% +exhibit right now on wood and on sort of + + + align:start position:0% +exhibit right now on wood and on sort of +using wood is a sculptural material and + + align:start position:0% +using wood is a sculptural material and + + + align:start position:0% +using wood is a sculptural material and +this is kind of one of their posters to + + align:start position:0% +this is kind of one of their posters to + + + align:start position:0% +this is kind of one of their posters to +advertise it uh so this thing was carved + + align:start position:0% +advertise it uh so this thing was carved + + + align:start position:0% +advertise it uh so this thing was carved +out of a single piece of wood I think um + + align:start position:0% +out of a single piece of wood I think um + + + align:start position:0% +out of a single piece of wood I think um +and they've got lots of other sort of + + align:start position:0% +and they've got lots of other sort of + + + align:start position:0% +and they've got lots of other sort of +sculptural wood so I thought you might + + align:start position:0% +sculptural wood so I thought you might + + + align:start position:0% +sculptural wood so I thought you might +like to see that um if you wanted to go + + align:start position:0% +like to see that um if you wanted to go + + + align:start position:0% +like to see that um if you wanted to go +to Salem there's a couple of options if + + align:start position:0% +to Salem there's a couple of options if + + + align:start position:0% +to Salem there's a couple of options if +you don't have a car you can take the + + align:start position:0% +you don't have a car you can take the + + + align:start position:0% +you don't have a car you can take the +commuter rail to Salem you can also take + + align:start position:0% +commuter rail to Salem you can also take + + + align:start position:0% +commuter rail to Salem you can also take +the ferry and if you take the ferry to + + align:start position:0% +the ferry and if you take the ferry to + + + align:start position:0% +the ferry and if you take the ferry to +Salem you can it's like a f minute walk + + align:start position:0% +Salem you can it's like a f minute walk + + + align:start position:0% +Salem you can it's like a f minute walk +to where the ferry lets you off to get + + align:start position:0% +to where the ferry lets you off to get + + + align:start position:0% +to where the ferry lets you off to get +to the PE body essics and it's a kind of + + align:start position:0% +to the PE body essics and it's a kind of + + + align:start position:0% +to the PE body essics and it's a kind of +neat Museum it's not too big it's kind + + align:start position:0% +neat Museum it's not too big it's kind + + + align:start position:0% +neat Museum it's not too big it's kind +of small um but it's it's a beautiful + + align:start position:0% +of small um but it's it's a beautiful + + + align:start position:0% +of small um but it's it's a beautiful +building and they have neat stuff there + + align:start position:0% +building and they have neat stuff there + + + align:start position:0% +building and they have neat stuff there +so you could go to the peab essics + + align:start position:0% +so you could go to the peab essics + + + align:start position:0% +so you could go to the peab essics +museum H very nice yeah you've been + + align:start position:0% +museum H very nice yeah you've been + + + align:start position:0% +museum H very nice yeah you've been +there yeah it's really nice yeah okay so + + align:start position:0% +there yeah it's really nice yeah okay so + + + align:start position:0% +there yeah it's really nice yeah okay so +I was going to talk about honeycomb like + + align:start position:0% +I was going to talk about honeycomb like + + + align:start position:0% +I was going to talk about honeycomb like +materials in nature today and I'm going + + align:start position:0% +materials in nature today and I'm going + + + align:start position:0% +materials in nature today and I'm going +to talk about wood today and I I might + + align:start position:0% +to talk about wood today and I I might + + + align:start position:0% +to talk about wood today and I I might +finish this today I might not and then I + + align:start position:0% +finish this today I might not and then I + + + align:start position:0% +finish this today I might not and then I +was going to talk about cork for a + + align:start position:0% +was going to talk about cork for a + + + align:start position:0% +was going to talk about cork for a +little bit um on Wednesday and then + + align:start position:0% +little bit um on Wednesday and then + + + align:start position:0% +little bit um on Wednesday and then +we'll start talking about Foams after + + align:start position:0% +we'll start talking about Foams after + + + align:start position:0% +we'll start talking about Foams after +that um so I have a couple of sort of + + align:start position:0% +that um so I have a couple of sort of + + + align:start position:0% +that um so I have a couple of sort of +cute little language historically things + + align:start position:0% +cute little language historically things + + + align:start position:0% +cute little language historically things +and you know how I like that stuff too + + align:start position:0% +and you know how I like that stuff too + + + align:start position:0% +and you know how I like that stuff too +so I have two things about um about + + align:start position:0% +so I have two things about um about + + + align:start position:0% +so I have two things about um about +words that are related to Wood so the + + align:start position:0% +words that are related to Wood so the + + + align:start position:0% +words that are related to Wood so the +word materials do you know where the + + align:start position:0% +word materials do you know where the + + + align:start position:0% +word materials do you know where the +word materials comes from it's uh it + + align:start position:0% +word materials comes from it's uh it + + + align:start position:0% +word materials comes from it's uh it +comes from the Latin so there's a Latin + + align:start position:0% +comes from the Latin so there's a Latin + + + align:start position:0% +comes from the Latin so there's a Latin +materias Materia and materias Materia + + align:start position:0% +materias Materia and materias Materia + + + align:start position:0% +materias Materia and materias Materia +means wood or the trunk of a tree so + + align:start position:0% +means wood or the trunk of a tree so + + + align:start position:0% +means wood or the trunk of a tree so +when you you know if you think of + + align:start position:0% +when you you know if you think of + + + align:start position:0% +when you you know if you think of +studying materials you know in olden + + align:start position:0% +studying materials you know in olden + + + align:start position:0% +studying materials you know in olden +times that was like studying wood and + + align:start position:0% +times that was like studying wood and + + + align:start position:0% +times that was like studying wood and +another cute thing that I found was that + + align:start position:0% +another cute thing that I found was that + + + align:start position:0% +another cute thing that I found was that +in Old Irish the names of the first few + + align:start position:0% +in Old Irish the names of the first few + + + align:start position:0% +in Old Irish the names of the first few +letters of the alphabet are named after + + align:start position:0% +letters of the alphabet are named after + + + align:start position:0% +letters of the alphabet are named after +trees so the letter A that's called alum + + align:start position:0% +trees so the letter A that's called alum + + + align:start position:0% +trees so the letter A that's called alum +in Old Irish and Alum is the word for + + align:start position:0% +in Old Irish and Alum is the word for + + + align:start position:0% +in Old Irish and Alum is the word for +Elm and B is I don't know if I'm saying + + align:start position:0% +Elm and B is I don't know if I'm saying + + + align:start position:0% +Elm and B is I don't know if I'm saying +these right it's called Beth and that's + + align:start position:0% +these right it's called Beth and that's + + + align:start position:0% +these right it's called Beth and that's +the word for Birch and C is call that's + + align:start position:0% +the word for Birch and C is call that's + + + align:start position:0% +the word for Birch and C is call that's +the word for Hazel and D is dare and + + align:start position:0% +the word for Hazel and D is dare and + + + align:start position:0% +the word for Hazel and D is dare and +that's the word for Oak and so they sort + + align:start position:0% +that's the word for Oak and so they sort + + + align:start position:0% +that's the word for Oak and so they sort +of named the letters of the alphabet + + align:start position:0% +of named the letters of the alphabet + + + align:start position:0% +of named the letters of the alphabet +after after different kinds of trees + + align:start position:0% +after after different kinds of trees + + + align:start position:0% +after after different kinds of trees +different kinds of woods so I just + + align:start position:0% +different kinds of woods so I just + + + align:start position:0% +different kinds of woods so I just +thought those were kind of interesting + + align:start position:0% +thought those were kind of interesting + + + align:start position:0% +thought those were kind of interesting +historical + + align:start position:0% +historical + + + align:start position:0% +historical +things okay so I wanted to start by + + align:start position:0% +things okay so I wanted to start by + + + align:start position:0% +things okay so I wanted to start by +talking about wood structure and then + + align:start position:0% +talking about wood structure and then + + + align:start position:0% +talking about wood structure and then +we're going to look at how wood deforms + + align:start position:0% +we're going to look at how wood deforms + + + align:start position:0% +we're going to look at how wood deforms +and fails and talk about um the data + + align:start position:0% +and fails and talk about um the data + + + align:start position:0% +and fails and talk about um the data +that people have measured for the wood + + align:start position:0% +that people have measured for the wood + + + align:start position:0% +that people have measured for the wood +properties things like stiffness and + + align:start position:0% +properties things like stiffness and + + + align:start position:0% +properties things like stiffness and +strength and then we'll talk a little + + align:start position:0% +strength and then we'll talk a little + + + align:start position:0% +strength and then we'll talk a little +bit about how the honeycomb models can + + align:start position:0% +bit about how the honeycomb models can + + + align:start position:0% +bit about how the honeycomb models can +be applied to understanding the + + align:start position:0% +be applied to understanding the + + + align:start position:0% +be applied to understanding the +mechanical properties of woods so this + + align:start position:0% +mechanical properties of woods so this + + + align:start position:0% +mechanical properties of woods so this +is kind of a generic trunk of the tree + + align:start position:0% +is kind of a generic trunk of the tree + + + align:start position:0% +is kind of a generic trunk of the tree +here and we're defining three axes the + + align:start position:0% +here and we're defining three axes the + + + align:start position:0% +here and we're defining three axes the +radial axis comes radially out of the + + align:start position:0% +radial axis comes radially out of the + + + align:start position:0% +radial axis comes radially out of the +tree there's the tangential axis so + + align:start position:0% +tree there's the tangential axis so + + + align:start position:0% +tree there's the tangential axis so +that's the X1 and the X2 axes and then + + align:start position:0% +that's the X1 and the X2 axes and then + + + align:start position:0% +that's the X1 and the X2 axes and then +there the longitudinal or the axial axis + + align:start position:0% +there the longitudinal or the axial axis + + + align:start position:0% +there the longitudinal or the axial axis +X3 so if you think of the wood as being + + align:start position:0% +X3 so if you think of the wood as being + + + align:start position:0% +X3 so if you think of the wood as being +in a very very simple way just like the + + align:start position:0% +in a very very simple way just like the + + + align:start position:0% +in a very very simple way just like the +honeycomb uh the radial would be this + + align:start position:0% +honeycomb uh the radial would be this + + + align:start position:0% +honeycomb uh the radial would be this +way on the tangential would be that way + + align:start position:0% +way on the tangential would be that way + + + align:start position:0% +way on the tangential would be that way +on and the axial would be that way on + + align:start position:0% +on and the axial would be that way on + + + align:start position:0% +on and the axial would be that way on +okay so it's it's like that and if you + + align:start position:0% +okay so it's it's like that and if you + + + align:start position:0% +okay so it's it's like that and if you +neglect the the growth rings you can say + + align:start position:0% +neglect the the growth rings you can say + + + align:start position:0% +neglect the the growth rings you can say +that the wood's orthotropic and that's + + align:start position:0% +that the wood's orthotropic and that's + + + align:start position:0% +that the wood's orthotropic and that's +typically what people do they neglect + + align:start position:0% +typically what people do they neglect + + + align:start position:0% +typically what people do they neglect +the growth rings and they say that it's + + align:start position:0% +the growth rings and they say that it's + + + align:start position:0% +the growth rings and they say that it's +orthotropic and the density of the woods + + align:start position:0% +orthotropic and the density of the woods + + + align:start position:0% +orthotropic and the density of the woods +the relative density ranges from about + + align:start position:0% +the relative density ranges from about + + + align:start position:0% +the relative density ranges from about +5% for balsa wood to about 80% % for + + align:start position:0% +5% for balsa wood to about 80% % for + + + align:start position:0% +5% for balsa wood to about 80% % for +lignum vti so I brought in some pieces + + align:start position:0% +lignum vti so I brought in some pieces + + + align:start position:0% +lignum vti so I brought in some pieces +of wood so this is balsa wood you're + + align:start position:0% +of wood so this is balsa wood you're + + + align:start position:0% +of wood so this is balsa wood you're +probably familiar you know making + + align:start position:0% +probably familiar you know making + + + align:start position:0% +probably familiar you know making +different kinds of models with Balsa so + + align:start position:0% +different kinds of models with Balsa so + + + align:start position:0% +different kinds of models with Balsa so +Balsa is very light grows in Ecuador and + + align:start position:0% +Balsa is very light grows in Ecuador and + + + align:start position:0% +Balsa is very light grows in Ecuador and +um it's the lightest wood and this is + + align:start position:0% +um it's the lightest wood and this is + + + align:start position:0% +um it's the lightest wood and this is +lignum Vita you're probably not so + + align:start position:0% +lignum Vita you're probably not so + + + align:start position:0% +lignum Vita you're probably not so +familiar with that this actually grows + + align:start position:0% +familiar with that this actually grows + + + align:start position:0% +familiar with that this actually grows +in Florida and it's the densest wood it + + align:start position:0% +in Florida and it's the densest wood it + + + align:start position:0% +in Florida and it's the densest wood it +has a relative density of 08 and it's so + + align:start position:0% +has a relative density of 08 and it's so + + + align:start position:0% +has a relative density of 08 and it's so +dense that if you put it in water it + + align:start position:0% +dense that if you put it in water it + + + align:start position:0% +dense that if you put it in water it +sinks so it's it's a very dense wood + + align:start position:0% +sinks so it's it's a very dense wood + + + align:start position:0% +sinks so it's it's a very dense wood +um and the way the wood cells grow is + + align:start position:0% +um and the way the wood cells grow is + + + align:start position:0% +um and the way the wood cells grow is +that if if you if you look at the sort + + align:start position:0% +that if if you if you look at the sort + + + align:start position:0% +that if if you if you look at the sort +of structure here of the tree there's + + align:start position:0% +of structure here of the tree there's + + + align:start position:0% +of structure here of the tree there's +the bark on the outside here and then + + align:start position:0% +the bark on the outside here and then + + + align:start position:0% +the bark on the outside here and then +there's the kind of wood cells inside + + align:start position:0% +there's the kind of wood cells inside + + + align:start position:0% +there's the kind of wood cells inside +the bark and there's a layer of cells in + + align:start position:0% +the bark and there's a layer of cells in + + + align:start position:0% +the bark and there's a layer of cells in +between the bark and the wood called the + + align:start position:0% +between the bark and the wood called the + + + align:start position:0% +between the bark and the wood called the +cambia layer and that's really the layer + + align:start position:0% +cambia layer and that's really the layer + + + align:start position:0% +cambia layer and that's really the layer +of cells that are alive and are dividing + + align:start position:0% +of cells that are alive and are dividing + + + align:start position:0% +of cells that are alive and are dividing +so if you think of the the wood cells + + align:start position:0% +so if you think of the the wood cells + + + align:start position:0% +so if you think of the the wood cells +there's uh they're living when they're + + align:start position:0% +there's uh they're living when they're + + + align:start position:0% +there's uh they're living when they're +in that little cambial layer there and + + align:start position:0% +in that little cambial layer there and + + + align:start position:0% +in that little cambial layer there and +they're dividing and that cambia layer + + align:start position:0% +they're dividing and that cambia layer + + + align:start position:0% +they're dividing and that cambia layer +the cells have a plasma membrane and a + + align:start position:0% +the cells have a plasma membrane and a + + + align:start position:0% +the cells have a plasma membrane and a +prot plast and then they they sort of + + align:start position:0% +prot plast and then they they sort of + + + align:start position:0% +prot plast and then they they sort of +exude the plant cell wall so a little + + align:start position:0% +exude the plant cell wall so a little + + + align:start position:0% +exude the plant cell wall so a little +like bone cells like if you think of + + align:start position:0% +like bone cells like if you think of + + + align:start position:0% +like bone cells like if you think of +bone in your body there's osteoblasts + + align:start position:0% +bone in your body there's osteoblasts + + + align:start position:0% +bone in your body there's osteoblasts +and osteoclasts different kinds of bone + + align:start position:0% +and osteoclasts different kinds of bone + + + align:start position:0% +and osteoclasts different kinds of bone +cells but the bone cells uh secrete the + + align:start position:0% +cells but the bone cells uh secrete the + + + align:start position:0% +cells but the bone cells uh secrete the +sort of collagen and the calcium + + align:start position:0% +sort of collagen and the calcium + + + align:start position:0% +sort of collagen and the calcium +phosphate that are the sort of hard + + align:start position:0% +phosphate that are the sort of hard + + + align:start position:0% +phosphate that are the sort of hard +mineral part of the bone that you think + + align:start position:0% +mineral part of the bone that you think + + + align:start position:0% +mineral part of the bone that you think +about the bone and that's not a living + + align:start position:0% +about the bone and that's not a living + + + align:start position:0% +about the bone and that's not a living +thing the cells are the living thing + + align:start position:0% +thing the cells are the living thing + + + align:start position:0% +thing the cells are the living thing +that's like an extracellular Matrix and + + align:start position:0% +that's like an extracellular Matrix and + + + align:start position:0% +that's like an extracellular Matrix and +the trees it's a little bit the same so + + align:start position:0% +the trees it's a little bit the same so + + + align:start position:0% +the trees it's a little bit the same so +there's the the living cells that are + + align:start position:0% +there's the the living cells that are + + + align:start position:0% +there's the the living cells that are +just under the bark and they have this + + align:start position:0% +just under the bark and they have this + + + align:start position:0% +just under the bark and they have this +plasma membrane and the protoplasm and + + align:start position:0% +plasma membrane and the protoplasm and + + + align:start position:0% +plasma membrane and the protoplasm and +over a few weeks they excrete the plant + + align:start position:0% +over a few weeks they excrete the plant + + + align:start position:0% +over a few weeks they excrete the plant +cell wall and then they die so the + + align:start position:0% +cell wall and then they die so the + + + align:start position:0% +cell wall and then they die so the +living cells die and you're left with + + align:start position:0% +living cells die and you're left with + + + align:start position:0% +living cells die and you're left with +the plant cell walls and then as the + + align:start position:0% +the plant cell walls and then as the + + + align:start position:0% +the plant cell walls and then as the +plant you know as the tree grows uh + + align:start position:0% +plant you know as the tree grows uh + + + align:start position:0% +plant you know as the tree grows uh +these you're always having a layer of + + align:start position:0% +these you're always having a layer of + + + align:start position:0% +these you're always having a layer of +these cambial cells and it forms bark on + + align:start position:0% +these cambial cells and it forms bark on + + + align:start position:0% +these cambial cells and it forms bark on +the outside and wood on the inside so + + align:start position:0% +the outside and wood on the inside so + + + align:start position:0% +the outside and wood on the inside so +there sort of a layer of cells that are + + align:start position:0% +there sort of a layer of cells that are + + + align:start position:0% +there sort of a layer of cells that are +differentiated such that on the outer + + align:start position:0% +differentiated such that on the outer + + + align:start position:0% +differentiated such that on the outer +layer they form the bark and on the + + align:start position:0% +layer they form the bark and on the + + + align:start position:0% +layer they form the bark and on the +inner layer they form the wood and as + + align:start position:0% +inner layer they form the wood and as + + + align:start position:0% +inner layer they form the wood and as +the wood you know as the tree grows that + + align:start position:0% +the wood you know as the tree grows that + + + align:start position:0% +the wood you know as the tree grows that +cambal layer is kind of expanding out + + align:start position:0% +cambal layer is kind of expanding out + + + align:start position:0% +cambal layer is kind of expanding out +radially so let me let me write some of + + align:start position:0% +radially so let me let me write some of + + + align:start position:0% +radially so let me let me write some of +these things + + align:start position:0% +these things + + + align:start position:0% +these things +down uh let's see + + align:start position:0% +down uh let's see + + + align:start position:0% +down uh let's see +okay okay so let me just write down + + align:start position:0% +okay okay so let me just write down + + + align:start position:0% +okay okay so let me just write down +those two little word things just cuz I + + align:start position:0% +those two little word things just cuz I + + + align:start position:0% +those two little word things just cuz I +think they're + + align:start position:0% +think they're + + + align:start position:0% +think they're +cute so the word materials is from the + + align:start position:0% +cute so the word materials is from the + + + align:start position:0% +cute so the word materials is from the +[Music] + + align:start position:0% + + + + align:start position:0% + +Latin material + + align:start position:0% + + + + align:start position:0% + +Materia and that means wood or the trunk + + align:start position:0% +Materia and that means wood or the trunk + + + align:start position:0% +Materia and that means wood or the trunk +of a + + align:start position:0% + + + + align:start position:0% + +tree and here's the little old Irish + + align:start position:0% +tree and here's the little old Irish + + + align:start position:0% +tree and here's the little old Irish +thing it's not like I think you know I'm + + align:start position:0% +thing it's not like I think you know I'm + + + align:start position:0% +thing it's not like I think you know I'm +not going to put this on the test or + + align:start position:0% +not going to put this on the test or + + + align:start position:0% +not going to put this on the test or +something I just thought it was cute + + align:start position:0% + + + + align:start position:0% + +um so the letter A + + align:start position:0% +um so the letter A + + + align:start position:0% +um so the letter A +is alum which is + + align:start position:0% +is alum which is + + + align:start position:0% +is alum which is +Elm letter + + align:start position:0% + + + + align:start position:0% + +B is be which is + + align:start position:0% +B is be which is + + + align:start position:0% +B is be which is +birch letter + + align:start position:0% +birch letter + + + align:start position:0% +birch letter +C was call was + + align:start position:0% +C was call was + + + align:start position:0% +C was call was +Hazel and D was + + align:start position:0% + + + + align:start position:0% + +dare and that's Oak okay that's just + + align:start position:0% +dare and that's Oak okay that's just + + + align:start position:0% +dare and that's Oak okay that's just +just for general interest + + align:start position:0% + + + + align:start position:0% + +so then the wood structure we can think + + align:start position:0% +so then the wood structure we can think + + + align:start position:0% +so then the wood structure we can think +of it as orthotropic if we ignore the um + + align:start position:0% +of it as orthotropic if we ignore the um + + + align:start position:0% +of it as orthotropic if we ignore the um +growth + + align:start position:0% + + + + align:start position:0% + +rings and if you have a a sort of large + + align:start position:0% +rings and if you have a a sort of large + + + align:start position:0% +rings and if you have a a sort of large +diameter tree and you take a piece of + + align:start position:0% +diameter tree and you take a piece of + + + align:start position:0% +diameter tree and you take a piece of +wood um you know not from the very + + align:start position:0% +wood um you know not from the very + + + align:start position:0% +wood um you know not from the very +center but from somewhere sort of near + + align:start position:0% +center but from somewhere sort of near + + + align:start position:0% +center but from somewhere sort of near +the outside then that's not a bad + + align:start position:0% +the outside then that's not a bad + + + align:start position:0% +the outside then that's not a bad +approximation + + align:start position:0% +approximation + + + align:start position:0% +approximation +and the relative density of the + + align:start position:0% + + + + align:start position:0% + +woods ranges from about 005 for + + align:start position:0% + + + + align:start position:0% + +Balsa to about 8 for lignum + + align:start position:0% + + + + align:start position:0% + +VII any Latin Scholars here they I took + + align:start position:0% +VII any Latin Scholars here they I took + + + align:start position:0% +VII any Latin Scholars here they I took +one year of Latin in high school they + + align:start position:0% +one year of Latin in high school they + + + align:start position:0% +one year of Latin in high school they +took Latin no no Latin so I think this + + align:start position:0% +took Latin no no Latin so I think this + + + align:start position:0% +took Latin no no Latin so I think this +means lignum V I think is Tree of Life V + + align:start position:0% +means lignum V I think is Tree of Life V + + + align:start position:0% +means lignum V I think is Tree of Life V +is the sort of + + align:start position:0% +is the sort of + + + align:start position:0% +is the sort of +life and when it has this ending AE it + + align:start position:0% +life and when it has this ending AE it + + + align:start position:0% +life and when it has this ending AE it +means of life so I think that's the tree + + align:start position:0% +means of life so I think that's the tree + + + align:start position:0% +means of life so I think that's the tree +of life is lignum + + align:start position:0% +of life is lignum + + + align:start position:0% +of life is lignum +V so trees have a cambia layer beneath + + align:start position:0% +V so trees have a cambia layer beneath + + + align:start position:0% +V so trees have a cambia layer beneath +the + + align:start position:0% + + + + align:start position:0% + +bark and the cell division occurs in + + align:start position:0% +bark and the cell division occurs in + + + align:start position:0% +bark and the cell division occurs in +that cambal layer + + align:start position:0% + + + + align:start position:0% + +so the new cells on the outer part turn + + align:start position:0% +so the new cells on the outer part turn + + + align:start position:0% +so the new cells on the outer part turn +into bark and the new cells on the inner + + align:start position:0% +into bark and the new cells on the inner + + + align:start position:0% +into bark and the new cells on the inner +part turn into wood + + align:start position:0% + + + + align:start position:0% + +okay and then we have the living plant + + align:start position:0% + + + + align:start position:0% + +cells that have the plasma + + align:start position:0% +cells that have the plasma + + + align:start position:0% +cells that have the plasma +membrane and the protoplast + + align:start position:0% + + + + align:start position:0% + +and those cells then secrete the plant + + align:start position:0% +and those cells then secrete the plant + + + align:start position:0% +and those cells then secrete the plant +cell + + align:start position:0% + + + + align:start position:0% + +wall which sort of surrounds them + + align:start position:0% + + + + align:start position:0% + +so in trees the living cells lay down + + align:start position:0% +so in trees the living cells lay down + + + align:start position:0% +so in trees the living cells lay down +the plant cell wall over a period of a + + align:start position:0% +the plant cell wall over a period of a + + + align:start position:0% +the plant cell wall over a period of a +few weeks and then the living cells die + + align:start position:0% +few weeks and then the living cells die + + + align:start position:0% +few weeks and then the living cells die +oops back here + + align:start position:0% + + + + align:start position:0% + +and you always retain a layer of those + + align:start position:0% +and you always retain a layer of those + + + align:start position:0% +and you always retain a layer of those +cambial cells + + align:start position:0% + + + + align:start position:0% + +so you may have heard if you have a tree + + align:start position:0% +so you may have heard if you have a tree + + + align:start position:0% +so you may have heard if you have a tree +and you you know you cut a ring around + + align:start position:0% +and you you know you cut a ring around + + + align:start position:0% +and you you know you cut a ring around +the tree and through the bark if you go + + align:start position:0% +the tree and through the bark if you go + + + align:start position:0% +the tree and through the bark if you go +into those cambial cells and you destroy + + align:start position:0% +into those cambial cells and you destroy + + + align:start position:0% +into those cambial cells and you destroy +them you kill the tree because you're + + align:start position:0% +them you kill the tree because you're + + + align:start position:0% +them you kill the tree because you're +killing that layer of living + + align:start position:0% + + + + align:start position:0% + +cells okay + + align:start position:0% + + + + align:start position:0% + +so then we want to look at the the + + align:start position:0% +so then we want to look at the the + + + align:start position:0% +so then we want to look at the the +cellular structure of the woods as well + + align:start position:0% +cellular structure of the woods as well + + + align:start position:0% +cellular structure of the woods as well +and I've got a couple of slides here + + align:start position:0% +and I've got a couple of slides here + + + align:start position:0% +and I've got a couple of slides here +this one is of soft woods and soft Woods + + align:start position:0% +this one is of soft woods and soft Woods + + + align:start position:0% +this one is of soft woods and soft Woods +have two types of cells they have + + align:start position:0% +have two types of cells they have + + + align:start position:0% +have two types of cells they have +trachead which are the bulk of these + + align:start position:0% +trachead which are the bulk of these + + + align:start position:0% +trachead which are the bulk of these +cells here and the trachead provide + + align:start position:0% +cells here and the trachead provide + + + align:start position:0% +cells here and the trachead provide +structural support and the trachead have + + align:start position:0% +structural support and the trachead have + + + align:start position:0% +structural support and the trachead have +little holes along the length of them at + + align:start position:0% +little holes along the length of them at + + + align:start position:0% +little holes along the length of them at +their ends called pits and those pits + + align:start position:0% +their ends called pits and those pits + + + align:start position:0% +their ends called pits and those pits +allow fluid transport um up and down the + + align:start position:0% +allow fluid transport um up and down the + + + align:start position:0% +allow fluid transport um up and down the +tree and then the softwood also has + + align:start position:0% +tree and then the softwood also has + + + align:start position:0% +tree and then the softwood also has +these Ray cells here so those are + + align:start position:0% +these Ray cells here so those are + + + align:start position:0% +these Ray cells here so those are +examples of Ray cells so this is a + + align:start position:0% +examples of Ray cells so this is a + + + align:start position:0% +examples of Ray cells so this is a +transverse section this is a + + align:start position:0% +transverse section this is a + + + align:start position:0% +transverse section this is a +longitudinal section here and the rays + + align:start position:0% +longitudinal section here and the rays + + + align:start position:0% +longitudinal section here and the rays +are penous cells which store sugars so + + align:start position:0% +are penous cells which store sugars so + + + align:start position:0% +are penous cells which store sugars so +softwoods have trachs and rays and then + + align:start position:0% +softwoods have trachs and rays and then + + + align:start position:0% +softwoods have trachs and rays and then +Hardwoods here's an example of a + + align:start position:0% +Hardwoods here's an example of a + + + align:start position:0% +Hardwoods here's an example of a +hardwood Oak they have three types of + + align:start position:0% +hardwood Oak they have three types of + + + align:start position:0% +hardwood Oak they have three types of +cells there's cells called fibers so + + align:start position:0% +cells there's cells called fibers so + + + align:start position:0% +cells there's cells called fibers so +these guys all in here would be fibers + + align:start position:0% +these guys all in here would be fibers + + + align:start position:0% +these guys all in here would be fibers +they provide the structural support they + + align:start position:0% +they provide the structural support they + + + align:start position:0% +they provide the structural support they +have vessels these really large cells + + align:start position:0% +have vessels these really large cells + + + align:start position:0% +have vessels these really large cells +that provide fluid transport up and down + + align:start position:0% +that provide fluid transport up and down + + + align:start position:0% +that provide fluid transport up and down +the tree and they also have Rays so + + align:start position:0% +the tree and they also have Rays so + + + align:start position:0% +the tree and they also have Rays so +here's some rays here and again those + + align:start position:0% +here's some rays here and again those + + + align:start position:0% +here's some rays here and again those +rays are parous cells that store sugars + + align:start position:0% +rays are parous cells that store sugars + + + align:start position:0% +rays are parous cells that store sugars +in the tree so let me just write down + + align:start position:0% +in the tree so let me just write down + + + align:start position:0% +in the tree so let me just write down +what all these cells are so + + align:start position:0% +what all these cells are so + + + align:start position:0% +what all these cells are so +in so in soft Woods the most of the + + align:start position:0% +in so in soft Woods the most of the + + + align:start position:0% +in so in soft Woods the most of the +cells are these trads so they make up + + align:start position:0% +cells are these trads so they make up + + + align:start position:0% +cells are these trads so they make up +the bulk of the tree + + align:start position:0% + + + + align:start position:0% + +uh something like 90% of the tree and + + align:start position:0% +uh something like 90% of the tree and + + + align:start position:0% +uh something like 90% of the tree and +they provide structural + + align:start position:0% + + + + align:start position:0% + +support they have holes in the cell wall + + align:start position:0% +support they have holes in the cell wall + + + align:start position:0% +support they have holes in the cell wall +for fluid transport and those are called + + align:start position:0% +for fluid transport and those are called + + + align:start position:0% +for fluid transport and those are called +pits + + align:start position:0% + + + + align:start position:0% + +and to give you some idea what size they + + align:start position:0% +and to give you some idea what size they + + + align:start position:0% +and to give you some idea what size they +are they're a few millimeters long so + + align:start position:0% +are they're a few millimeters long so + + + align:start position:0% +are they're a few millimeters long so +something like 2 and 1/2 to 7 mm + + align:start position:0% +something like 2 and 1/2 to 7 mm + + + align:start position:0% +something like 2 and 1/2 to 7 mm +long and then there're tens of microns + + align:start position:0% +long and then there're tens of microns + + + align:start position:0% +long and then there're tens of microns +in the other two directions so there's + + align:start position:0% +in the other two directions so there's + + + align:start position:0% +in the other two directions so there's +something like 20 to 80 microns + + align:start position:0% +something like 20 to 80 microns + + + align:start position:0% +something like 20 to 80 microns +across and the cell wall thickness T is + + align:start position:0% +across and the cell wall thickness T is + + + align:start position:0% +across and the cell wall thickness T is +usually a few microns so something + + align:start position:0% +usually a few microns so something + + + align:start position:0% +usually a few microns so something +between about 2 and seven microns so + + align:start position:0% +between about 2 and seven microns so + + + align:start position:0% +between about 2 and seven microns so +typically the denser the wood the + + align:start position:0% +typically the denser the wood the + + + align:start position:0% +typically the denser the wood the +thicker the cell wall is going to be + + align:start position:0% +thicker the cell wall is going to be + + + align:start position:0% +thicker the cell wall is going to be +oops let see if I can put the Rays down + + align:start position:0% +oops let see if I can put the Rays down + + + align:start position:0% +oops let see if I can put the Rays down +here put on the same + + align:start position:0% + + + + align:start position:0% + +board so the rays are parous cells that + + align:start position:0% +board so the rays are parous cells that + + + align:start position:0% +board so the rays are parous cells that +store + + align:start position:0% + + + + align:start position:0% + +Sugar okay + + align:start position:0% + + + + align:start position:0% + +and then the hardwoods have three types + + align:start position:0% +and then the hardwoods have three types + + + align:start position:0% +and then the hardwoods have three types +of cells they have the fibers that + + align:start position:0% +of cells they have the fibers that + + + align:start position:0% +of cells they have the fibers that +provide the structural + + align:start position:0% + + + + align:start position:0% + +support and the amount of cells that are + + align:start position:0% +support and the amount of cells that are + + + align:start position:0% +support and the amount of cells that are +fibers varies depending on the species + + align:start position:0% +fibers varies depending on the species + + + align:start position:0% +fibers varies depending on the species +but it's usually somewhere around 35 to + + align:start position:0% +but it's usually somewhere around 35 to + + + align:start position:0% +but it's usually somewhere around 35 to +70% of the + + align:start position:0% + + + + align:start position:0% + +cells and then they have the vessels + + align:start position:0% +cells and then they have the vessels + + + align:start position:0% +cells and then they have the vessels +which are the sap + + align:start position:0% + + + + align:start position:0% + +channels that provides for the + + align:start position:0% +channels that provides for the + + + align:start position:0% +channels that provides for the +conduction of + + align:start position:0% + + + + align:start position:0% + +fluids and that's between about 6 and + + align:start position:0% +fluids and that's between about 6 and + + + align:start position:0% +fluids and that's between about 6 and +55% of the cells + + align:start position:0% +55% of the cells + + + align:start position:0% +55% of the cells +and then again there's rays that store + + align:start position:0% + + + + align:start position:0% + +sugars they usually make up about 10 to + + align:start position:0% +sugars they usually make up about 10 to + + + align:start position:0% +sugars they usually make up about 10 to +30% of the + + align:start position:0% + + + + align:start position:0% + +cells so there's the structure of the + + align:start position:0% +cells so there's the structure of the + + + align:start position:0% +cells so there's the structure of the +sort of cellular structure that this + + align:start position:0% +sort of cellular structure that this + + + align:start position:0% +sort of cellular structure that this +kind of length scale of sort tens of + + align:start position:0% +kind of length scale of sort tens of + + + align:start position:0% +kind of length scale of sort tens of +microns and then there's also a + + align:start position:0% +microns and then there's also a + + + align:start position:0% +microns and then there's also a +structure within the cell wall itself + + align:start position:0% +structure within the cell wall itself + + + align:start position:0% +structure within the cell wall itself +and the cell wall itself um is made up + + align:start position:0% +and the cell wall itself um is made up + + + align:start position:0% +and the cell wall itself um is made up +of cellulose fibral in a matrix of + + align:start position:0% +of cellulose fibral in a matrix of + + + align:start position:0% +of cellulose fibral in a matrix of +lignan and something called + + align:start position:0% +lignan and something called + + + align:start position:0% +lignan and something called +hemicellulose so if you look at the + + align:start position:0% +hemicellulose so if you look at the + + + align:start position:0% +hemicellulose so if you look at the +cellulose structure the cellulose has um + + align:start position:0% +cellulose structure the cellulose has um + + + align:start position:0% +cellulose structure the cellulose has um +a regular structure sort of periodic + + align:start position:0% +a regular structure sort of periodic + + + align:start position:0% +a regular structure sort of periodic +lattice uh and it's crystallin for most + + align:start position:0% +lattice uh and it's crystallin for most + + + align:start position:0% +lattice uh and it's crystallin for most +of the length of the fibral so this is + + align:start position:0% +of the length of the fibral so this is + + + align:start position:0% +of the length of the fibral so this is +the the structure of the the cellulose + + align:start position:0% +the the structure of the the cellulose + + + align:start position:0% +the the structure of the the cellulose +here and uh this is showing at a + + align:start position:0% +here and uh this is showing at a + + + align:start position:0% +here and uh this is showing at a +slightly larger length scale if might + + align:start position:0% +slightly larger length scale if might + + + align:start position:0% +slightly larger length scale if might +have a crystalline region here and then + + align:start position:0% +have a crystalline region here and then + + + align:start position:0% +have a crystalline region here and then +a non-crystalline region here and these + + align:start position:0% +a non-crystalline region here and these + + + align:start position:0% +a non-crystalline region here and these +macrofibrils which are made up of + + align:start position:0% +macrofibrils which are made up of + + + align:start position:0% +macrofibrils which are made up of +bundles of microf fibral are about uh 10 + + align:start position:0% +bundles of microf fibral are about uh 10 + + + align:start position:0% +bundles of microf fibral are about uh 10 +to 25 nanm and each one of the microf + + align:start position:0% +to 25 nanm and each one of the microf + + + align:start position:0% +to 25 nanm and each one of the microf +fibral might be 3 to four nanm across so + + align:start position:0% +fibral might be 3 to four nanm across so + + + align:start position:0% +fibral might be 3 to four nanm across so +you have these cellulose fibers and then + + align:start position:0% +you have these cellulose fibers and then + + + align:start position:0% +you have these cellulose fibers and then +the cell wall is made up of different + + align:start position:0% +the cell wall is made up of different + + + align:start position:0% +the cell wall is made up of different +layers so there's What's called the + + align:start position:0% +layers so there's What's called the + + + align:start position:0% +layers so there's What's called the +primary wall here which has a random + + align:start position:0% +primary wall here which has a random + + + align:start position:0% +primary wall here which has a random +arrangement of the cellulose fibral then + + align:start position:0% +arrangement of the cellulose fibral then + + + align:start position:0% +arrangement of the cellulose fibral then +there's an outer layer here these are + + align:start position:0% +there's an outer layer here these are + + + align:start position:0% +there's an outer layer here these are +all called secondary layers this is s uh + + align:start position:0% +all called secondary layers this is s uh + + + align:start position:0% +all called secondary layers this is s uh +let's see that's + + align:start position:0% +let's see that's + + + align:start position:0% +let's see that's +S1 yeah that's S1 uh and it has this + + align:start position:0% +S1 yeah that's S1 uh and it has this + + + align:start position:0% +S1 yeah that's S1 uh and it has this +arrangement of the uh fibral then + + align:start position:0% +arrangement of the uh fibral then + + + align:start position:0% +arrangement of the uh fibral then +there's a a layer called S2 and it's + + align:start position:0% +there's a a layer called S2 and it's + + + align:start position:0% +there's a a layer called S2 and it's +generally the thickest layer in the cell + + align:start position:0% +generally the thickest layer in the cell + + + align:start position:0% +generally the thickest layer in the cell +wall and the cellulose fibral are + + align:start position:0% +wall and the cellulose fibral are + + + align:start position:0% +wall and the cellulose fibral are +aligned not perfectly vertical but a + + align:start position:0% +aligned not perfectly vertical but a + + + align:start position:0% +aligned not perfectly vertical but a +little off the vertical and the angle + + align:start position:0% +little off the vertical and the angle + + + align:start position:0% +little off the vertical and the angle +between the vertical and the orientation + + align:start position:0% +between the vertical and the orientation + + + align:start position:0% +between the vertical and the orientation +of the cellulose fibers is called the + + align:start position:0% +of the cellulose fibers is called the + + + align:start position:0% +of the cellulose fibers is called the +microfibrillar angle and then there's a + + align:start position:0% +microfibrillar angle and then there's a + + + align:start position:0% +microfibrillar angle and then there's a +third third layer here S3 with again a + + align:start position:0% +third third layer here S3 with again a + + + align:start position:0% +third third layer here S3 with again a +different winding of the fibers so + + align:start position:0% +different winding of the fibers so + + + align:start position:0% +different winding of the fibers so +because the S2 layer is the thickest + + align:start position:0% +because the S2 layer is the thickest + + + align:start position:0% +because the S2 layer is the thickest +layer and because the fibral are closest + + align:start position:0% +layer and because the fibral are closest + + + align:start position:0% +layer and because the fibral are closest +to the vertical axis the S2 layer + + align:start position:0% +to the vertical axis the S2 layer + + + align:start position:0% +to the vertical axis the S2 layer +actually contributes the most to the um + + align:start position:0% +actually contributes the most to the um + + + align:start position:0% +actually contributes the most to the um +longitudinal modulus and stiffness of + + align:start position:0% +longitudinal modulus and stiffness of + + + align:start position:0% +longitudinal modulus and stiffness of +the and strength of the cell wall so + + align:start position:0% +the and strength of the cell wall so + + + align:start position:0% +the and strength of the cell wall so +that's kind of the layer of of the cell + + align:start position:0% +that's kind of the layer of of the cell + + + align:start position:0% +that's kind of the layer of of the cell +arrangement of the cell wall and then so + + align:start position:0% +arrangement of the cell wall and then so + + + align:start position:0% +arrangement of the cell wall and then so +that one cell would have that another + + align:start position:0% +that one cell would have that another + + + align:start position:0% +that one cell would have that another +cell would have that and in between the + + align:start position:0% +cell would have that and in between the + + + align:start position:0% +cell would have that and in between the +two there's a layer called the middle + + align:start position:0% +two there's a layer called the middle + + + align:start position:0% +two there's a layer called the middle +Lela that kind of glues them together so + + align:start position:0% +Lela that kind of glues them together so + + + align:start position:0% +Lela that kind of glues them together so +that's the arrangement of the + + align:start position:0% +that's the arrangement of the + + + align:start position:0% +that's the arrangement of the +cells um so oops let me scoot over here + + align:start position:0% +cells um so oops let me scoot over here + + + align:start position:0% +cells um so oops let me scoot over here +so the cells are often modeled as a + + align:start position:0% +so the cells are often modeled as a + + + align:start position:0% +so the cells are often modeled as a +fiber reinforced composite um that has + + align:start position:0% +fiber reinforced composite um that has + + + align:start position:0% +fiber reinforced composite um that has +four layers to + + align:start position:0% +four layers to + + + align:start position:0% +four layers to +it and in each layer there's different + + align:start position:0% +it and in each layer there's different + + + align:start position:0% +it and in each layer there's different +volume fraction of the fibers and + + align:start position:0% +volume fraction of the fibers and + + + align:start position:0% +volume fraction of the fibers and +different orientation of the fibers + + align:start position:0% + + + + align:start position:0% + +okay so the cell wall has this fiber + + align:start position:0% +okay so the cell wall has this fiber + + + align:start position:0% +okay so the cell wall has this fiber +reinforced structure + + align:start position:0% + + + + align:start position:0% + +there's the + + align:start position:0% +there's the + + + align:start position:0% +there's the +cellulose + + align:start position:0% +cellulose + + + align:start position:0% +cellulose +fibers in a matrix of Li and + + align:start position:0% + + + + align:start position:0% + +hemicellulose and there's four layers + + align:start position:0% +hemicellulose and there's four layers + + + align:start position:0% +hemicellulose and there's four layers +each with the fibers in a different + + align:start position:0% +each with the fibers in a different + + + align:start position:0% +each with the fibers in a different +orientation + + align:start position:0% + + + + align:start position:0% + +and then there's the middle Lela between + + align:start position:0% +and then there's the middle Lela between + + + align:start position:0% +and then there's the middle Lela between +the two cells + + align:start position:0% + + + + align:start position:0% + +so in doing the modeling of of a + + align:start position:0% +so in doing the modeling of of a + + + align:start position:0% +so in doing the modeling of of a +material like wood you need to know what + + align:start position:0% +material like wood you need to know what + + + align:start position:0% +material like wood you need to know what +the properties of a cell wall material + + align:start position:0% +the properties of a cell wall material + + + align:start position:0% +the properties of a cell wall material +are because obviously the properties of + + align:start position:0% +are because obviously the properties of + + + align:start position:0% +are because obviously the properties of +the wood would depend on the cell wall + + align:start position:0% +the wood would depend on the cell wall + + + align:start position:0% +the wood would depend on the cell wall +properties and it turns out that they're + + align:start position:0% +properties and it turns out that they're + + + align:start position:0% +properties and it turns out that they're +similar they're not exactly the same but + + align:start position:0% +similar they're not exactly the same but + + + align:start position:0% +similar they're not exactly the same but +they're similar in different species of + + align:start position:0% +they're similar in different species of + + + align:start position:0% +they're similar in different species of +wood so we're going to call + + align:start position:0% +wood so we're going to call + + + align:start position:0% +wood so we're going to call +them more or less the same + + align:start position:0% + + + + align:start position:0% + +so the density of the solid + + align:start position:0% +so the density of the solid + + + align:start position:0% +so the density of the solid +is500 kg per cubic + + align:start position:0% +is500 kg per cubic + + + align:start position:0% +is500 kg per cubic +meter the modulus of the solid in the + + align:start position:0% +meter the modulus of the solid in the + + + align:start position:0% +meter the modulus of the solid in the +axial direction is 35 Gap + + align:start position:0% +axial direction is 35 Gap + + + align:start position:0% +axial direction is 35 Gap +pascals the modulus in the tangential + + align:start position:0% +pascals the modulus in the tangential + + + align:start position:0% +pascals the modulus in the tangential +direction or transverse direction is 10 + + align:start position:0% +direction or transverse direction is 10 + + + align:start position:0% +direction or transverse direction is 10 +Gap pascals and the strength of the + + align:start position:0% +Gap pascals and the strength of the + + + align:start position:0% +Gap pascals and the strength of the +solid in the axial + + align:start position:0% +solid in the axial + + + align:start position:0% +solid in the axial +direction is 350 megap + + align:start position:0% + + + + align:start position:0% + +pascals and the strength in the + + align:start position:0% +pascals and the strength in the + + + align:start position:0% +pascals and the strength in the +transverse direction is about + + align:start position:0% + + + + align:start position:0% + +135 so here a means axial + + align:start position:0% +135 so here a means axial + + + align:start position:0% +135 so here a means axial +Direction and T is + + align:start position:0% + + + + align:start position:0% + +transverse and just for + + align:start position:0% +transverse and just for + + + align:start position:0% +transverse and just for +comparison if you just look at + + align:start position:0% +comparison if you just look at + + + align:start position:0% +comparison if you just look at +cellulose cellulose has some pretty + + align:start position:0% +cellulose cellulose has some pretty + + + align:start position:0% +cellulose cellulose has some pretty +amazing properties the modulus of + + align:start position:0% +amazing properties the modulus of + + + align:start position:0% +amazing properties the modulus of +cellulose is about 140 gigap pascals + + align:start position:0% +cellulose is about 140 gigap pascals + + + align:start position:0% +cellulose is about 140 gigap pascals +which is very high for a polymer and the + + align:start position:0% +which is very high for a polymer and the + + + align:start position:0% +which is very high for a polymer and the +strength of cellulose fibers run between + + align:start position:0% +strength of cellulose fibers run between + + + align:start position:0% +strength of cellulose fibers run between +about 700 and + + align:start position:0% +about 700 and + + + align:start position:0% +about 700 and +900 megap pascals so the cellulose + + align:start position:0% +900 megap pascals so the cellulose + + + align:start position:0% +900 megap pascals so the cellulose +fibers have very impressive properties + + align:start position:0% +fibers have very impressive properties + + + align:start position:0% +fibers have very impressive properties +and that's one of the things that gives + + align:start position:0% +and that's one of the things that gives + + + align:start position:0% +and that's one of the things that gives +wood very good properties + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +right so the next thing is I want to + + align:start position:0% +right so the next thing is I want to + + + align:start position:0% +right so the next thing is I want to +show you some stress strain curves for + + align:start position:0% +show you some stress strain curves for + + + align:start position:0% +show you some stress strain curves for +wood and you'll see how similar they are + + align:start position:0% +wood and you'll see how similar they are + + + align:start position:0% +wood and you'll see how similar they are +to the Honeycombs that we looked at + + align:start position:0% +to the Honeycombs that we looked at + + + align:start position:0% +to the Honeycombs that we looked at +before um and then we'll look at how the + + align:start position:0% +before um and then we'll look at how the + + + align:start position:0% +before um and then we'll look at how the +cells are deforming as they're getting + + align:start position:0% +cells are deforming as they're getting + + + align:start position:0% +cells are deforming as they're getting +loaded and from that we're going to do + + align:start position:0% +loaded and from that we're going to do + + + align:start position:0% +loaded and from that we're going to do +some modeling + + align:start position:0% +some modeling + + + align:start position:0% +some modeling +okay so let me just wait till people + + align:start position:0% +okay so let me just wait till people + + + align:start position:0% +okay so let me just wait till people +have caught up are we caught + + align:start position:0% +have caught up are we caught + + + align:start position:0% +have caught up are we caught +up more or less okay okay so these are + + align:start position:0% +up more or less okay okay so these are + + + align:start position:0% +up more or less okay okay so these are +all compression curves so I'm just going + + align:start position:0% +all compression curves so I'm just going + + + align:start position:0% +all compression curves so I'm just going +to talk about compression so these are + + align:start position:0% +to talk about compression so these are + + + align:start position:0% +to talk about compression so these are +curves for different types of woods and + + align:start position:0% +curves for different types of woods and + + + align:start position:0% +curves for different types of woods and +on the left the wood is loaded in in the + + align:start position:0% +on the left the wood is loaded in in the + + + align:start position:0% +on the left the wood is loaded in in the +tangential Direction so in terms of you + + align:start position:0% +tangential Direction so in terms of you + + + align:start position:0% +tangential Direction so in terms of you +know this sort of honeycomb model it's + + align:start position:0% +know this sort of honeycomb model it's + + + align:start position:0% +know this sort of honeycomb model it's +loading it kind of this this way on like + + align:start position:0% +loading it kind of this this way on like + + + align:start position:0% +loading it kind of this this way on like +that and on the right are a set of + + align:start position:0% +that and on the right are a set of + + + align:start position:0% +that and on the right are a set of +Curves for wood loaded in axial + + align:start position:0% +Curves for wood loaded in axial + + + align:start position:0% +Curves for wood loaded in axial +compression so in axial compression + + align:start position:0% +compression so in axial compression + + + align:start position:0% +compression so in axial compression +we're loading it that way on okay and + + align:start position:0% +we're loading it that way on okay and + + + align:start position:0% +we're loading it that way on okay and +we've got different species here so the + + align:start position:0% +we've got different species here so the + + + align:start position:0% +we've got different species here so the +lowest density is Balsa around about 100 + + align:start position:0% +lowest density is Balsa around about 100 + + + align:start position:0% +lowest density is Balsa around about 100 +kg per cubic meter the densest species + + align:start position:0% +kg per cubic meter the densest species + + + align:start position:0% +kg per cubic meter the densest species +on this plot is Beach which is around + + align:start position:0% +on this plot is Beach which is around + + + align:start position:0% +on this plot is Beach which is around +700 kilog per cubic meter and then + + align:start position:0% +700 kilog per cubic meter and then + + + align:start position:0% +700 kilog per cubic meter and then +there's pine and Willow some other + + align:start position:0% +there's pine and Willow some other + + + align:start position:0% +there's pine and Willow some other +species in between here so you can see + + align:start position:0% +species in between here so you can see + + + align:start position:0% +species in between here so you can see +the shapes of the curve look just like + + align:start position:0% +the shapes of the curve look just like + + + align:start position:0% +the shapes of the curve look just like +the um curves that we had for the + + align:start position:0% +the um curves that we had for the + + + align:start position:0% +the um curves that we had for the +Honeycombs so here there's a linear + + align:start position:0% +Honeycombs so here there's a linear + + + align:start position:0% +Honeycombs so here there's a linear +elastic bit there's a stress plateau and + + align:start position:0% +elastic bit there's a stress plateau and + + + align:start position:0% +elastic bit there's a stress plateau and +there's a densification bit so and then + + align:start position:0% +there's a densification bit so and then + + + align:start position:0% +there's a densification bit so and then +as the density goes up the it gets + + align:start position:0% +as the density goes up the it gets + + + align:start position:0% +as the density goes up the it gets +stiffer and the strain at which the + + align:start position:0% +stiffer and the strain at which the + + + align:start position:0% +stiffer and the strain at which the +densification occurs uh gets smaller and + + align:start position:0% +densification occurs uh gets smaller and + + + align:start position:0% +densification occurs uh gets smaller and +the strength gets higher uh and if we + + align:start position:0% +the strength gets higher uh and if we + + + align:start position:0% +the strength gets higher uh and if we +look at the + + align:start position:0% +look at the + + + align:start position:0% +look at the +axial properties the shape of the curve + + align:start position:0% +axial properties the shape of the curve + + + align:start position:0% +axial properties the shape of the curve +is similar we get linear elastic stress + + align:start position:0% +is similar we get linear elastic stress + + + align:start position:0% +is similar we get linear elastic stress +plateau densification uh but if you look + + align:start position:0% +plateau densification uh but if you look + + + align:start position:0% +plateau densification uh but if you look +at the scale here this scale goes from 0 + + align:start position:0% +at the scale here this scale goes from 0 + + + align:start position:0% +at the scale here this scale goes from 0 +to 100 whereas that scale went from 0 to + + align:start position:0% +to 100 whereas that scale went from 0 to + + + align:start position:0% +to 100 whereas that scale went from 0 to +20 and so this this stiffness and the + + align:start position:0% +20 and so this this stiffness and the + + + align:start position:0% +20 and so this this stiffness and the +strength along the grain are much higher + + align:start position:0% +strength along the grain are much higher + + + align:start position:0% +strength along the grain are much higher +than they are across the Grain and you + + align:start position:0% +than they are across the Grain and you + + + align:start position:0% +than they are across the Grain and you +probably already know that wood is + + align:start position:0% +probably already know that wood is + + + align:start position:0% +probably already know that wood is +stronger and stiffer along the grain + + align:start position:0% +stronger and stiffer along the grain + + + align:start position:0% +stronger and stiffer along the grain +than across the grain okay so that's + + align:start position:0% +than across the grain okay so that's + + + align:start position:0% +than across the grain okay so that's +when the stress strin curves looked like + + align:start position:0% +when the stress strin curves looked like + + + align:start position:0% +when the stress strin curves looked like +and the fact that we're getting the + + align:start position:0% +and the fact that we're getting the + + + align:start position:0% +and the fact that we're getting the +curves that look like that makes us + + align:start position:0% +curves that look like that makes us + + + align:start position:0% +curves that look like that makes us +think maybe the mechanisms of + + align:start position:0% +think maybe the mechanisms of + + + align:start position:0% +think maybe the mechanisms of +deformation and failure similar to the + + align:start position:0% +deformation and failure similar to the + + + align:start position:0% +deformation and failure similar to the +honeycomb 2 so here's a here's a set of + + align:start position:0% +honeycomb 2 so here's a here's a set of + + + align:start position:0% +honeycomb 2 so here's a here's a set of +Curves for Balsa all plotted on the same + + align:start position:0% +Curves for Balsa all plotted on the same + + + align:start position:0% +Curves for Balsa all plotted on the same +scale and again you can see the the for + + align:start position:0% +scale and again you can see the the for + + + align:start position:0% +scale and again you can see the the for +loading across the grain either in the + + align:start position:0% +loading across the grain either in the + + + align:start position:0% +loading across the grain either in the +radial or the tangential Direction the + + align:start position:0% +radial or the tangential Direction the + + + align:start position:0% +radial or the tangential Direction the +stiffness and the strength is a lot less + + align:start position:0% +stiffness and the strength is a lot less + + + align:start position:0% +stiffness and the strength is a lot less +than if you load it in the axial + + align:start position:0% +than if you load it in the axial + + + align:start position:0% +than if you load it in the axial +Direction so a number of years ago we + + align:start position:0% +Direction so a number of years ago we + + + align:start position:0% +Direction so a number of years ago we +had a project on Balsa and the thing we + + align:start position:0% +had a project on Balsa and the thing we + + + align:start position:0% +had a project on Balsa and the thing we +were interested in doing was looking at + + align:start position:0% +were interested in doing was looking at + + + align:start position:0% +were interested in doing was looking at +how the cells deformed and failed and + + align:start position:0% +how the cells deformed and failed and + + + align:start position:0% +how the cells deformed and failed and +because bals is a low density wood it + + align:start position:0% +because bals is a low density wood it + + + align:start position:0% +because bals is a low density wood it +was easier to see the deformation in the + + align:start position:0% +was easier to see the deformation in the + + + align:start position:0% +was easier to see the deformation in the +cells because the cell walls were thin + + align:start position:0% +cells because the cell walls were thin + + + align:start position:0% +cells because the cell walls were thin +so that's why we chose Balsa I actually + + align:start position:0% +so that's why we chose Balsa I actually + + + align:start position:0% +so that's why we chose Balsa I actually +have a project on Balsa right now and um + + align:start position:0% +have a project on Balsa right now and um + + + align:start position:0% +have a project on Balsa right now and um +Sardar my postto is doing more detailed + + align:start position:0% +Sardar my postto is doing more detailed + + + align:start position:0% +Sardar my postto is doing more detailed +kind of finite element modeling trying + + align:start position:0% +kind of finite element modeling trying + + + align:start position:0% +kind of finite element modeling trying +to represent the structure of Balsa and + + align:start position:0% +to represent the structure of Balsa and + + + align:start position:0% +to represent the structure of Balsa and +I think I mentioned the reason we're + + align:start position:0% +I think I mentioned the reason we're + + + align:start position:0% +I think I mentioned the reason we're +interested in it is that Balsa is used + + align:start position:0% +interested in it is that Balsa is used + + + align:start position:0% +interested in it is that Balsa is used +as a core in Sandwich panels in wind + + align:start position:0% +as a core in Sandwich panels in wind + + + align:start position:0% +as a core in Sandwich panels in wind +turbine blades and uh it's it's actually + + align:start position:0% +turbine blades and uh it's it's actually + + + align:start position:0% +turbine blades and uh it's it's actually +the best material that they can find + + align:start position:0% +the best material that they can find + + + align:start position:0% +the best material that they can find +it's better than any engineering + + align:start position:0% +it's better than any engineering + + + align:start position:0% +it's better than any engineering +material so that's + + align:start position:0% +material so that's + + + align:start position:0% +material so that's +comparing the three curves for Balsa and + + align:start position:0% +comparing the three curves for Balsa and + + + align:start position:0% +comparing the three curves for Balsa and +then if you look um at a specimen that's + + align:start position:0% +then if you look um at a specimen that's + + + align:start position:0% +then if you look um at a specimen that's +loaded in the sem you can uh with a + + align:start position:0% +loaded in the sem you can uh with a + + + align:start position:0% +loaded in the sem you can uh with a +loading stage you can measure the stress + + align:start position:0% +loading stage you can measure the stress + + + align:start position:0% +loading stage you can measure the stress +strain curve and you can take + + align:start position:0% +strain curve and you can take + + + align:start position:0% +strain curve and you can take +photographs of what the cellular + + align:start position:0% +photographs of what the cellular + + + align:start position:0% +photographs of what the cellular +structure looks like at different stages + + align:start position:0% +structure looks like at different stages + + + align:start position:0% +structure looks like at different stages +of loading so here this picture one is + + align:start position:0% +of loading so here this picture one is + + + align:start position:0% +of loading so here this picture one is +unloaded and these four Images here are + + align:start position:0% +unloaded and these four Images here are + + + align:start position:0% +unloaded and these four Images here are +looking at the same section of cells the + + align:start position:0% +looking at the same section of cells the + + + align:start position:0% +looking at the same section of cells the +same area of cells and you can see + + align:start position:0% +same area of cells and you can see + + + align:start position:0% +same area of cells and you can see +there's a big vessel here and that's the + + align:start position:0% +there's a big vessel here and that's the + + + align:start position:0% +there's a big vessel here and that's the +same vessel there so here this image two + + align:start position:0% +same vessel there so here this image two + + + align:start position:0% +same vessel there so here this image two +is at this point on the stress strain + + align:start position:0% +is at this point on the stress strain + + + align:start position:0% +is at this point on the stress strain +curve here's three at that point and + + align:start position:0% +curve here's three at that point and + + + align:start position:0% +curve here's three at that point and +four is at that point so if you look at + + align:start position:0% +four is at that point so if you look at + + + align:start position:0% +four is at that point so if you look at +this carefully and I've got another + + align:start position:0% +this carefully and I've got another + + + align:start position:0% +this carefully and I've got another +higher meg picture I'll show you in a + + align:start position:0% +higher meg picture I'll show you in a + + + align:start position:0% +higher meg picture I'll show you in a +second um you can see that what's + + align:start position:0% +second um you can see that what's + + + align:start position:0% +second um you can see that what's +happening is the cell walls are bending + + align:start position:0% +happening is the cell walls are bending + + + align:start position:0% +happening is the cell walls are bending +so it's kind of like taking my honeycomb + + align:start position:0% +so it's kind of like taking my honeycomb + + + align:start position:0% +so it's kind of like taking my honeycomb +like this and I'm doing that to it and + + align:start position:0% +like this and I'm doing that to it and + + + align:start position:0% +like this and I'm doing that to it and +the cell walls are bending so just the + + align:start position:0% +the cell walls are bending so just the + + + align:start position:0% +the cell walls are bending so just the +same as the honeycomb and then + + align:start position:0% +same as the honeycomb and then + + + align:start position:0% +same as the honeycomb and then +eventually if I load it enough you get + + align:start position:0% +eventually if I load it enough you get + + + align:start position:0% +eventually if I load it enough you get +to this sort of densified stage and + + align:start position:0% +to this sort of densified stage and + + + align:start position:0% +to this sort of densified stage and +you're doing this and the stress strain + + align:start position:0% +you're doing this and the stress strain + + + align:start position:0% +you're doing this and the stress strain +curve increases sharply so here you can + + align:start position:0% +curve increases sharply so here you can + + + align:start position:0% +curve increases sharply so here you can +see how the cells have densified over + + align:start position:0% +see how the cells have densified over + + + align:start position:0% +see how the cells have densified over +here it kind of looks a lot like my + + align:start position:0% +here it kind of looks a lot like my + + + align:start position:0% +here it kind of looks a lot like my +honeycomb when I oops maybe I do it this + + align:start position:0% +honeycomb when I oops maybe I do it this + + + align:start position:0% +honeycomb when I oops maybe I do it this +way when I smush it up like that it + + align:start position:0% +way when I smush it up like that it + + + align:start position:0% +way when I smush it up like that it +looks kind of + + align:start position:0% +looks kind of + + + align:start position:0% +looks kind of +similar so if we look at the higher mag + + align:start position:0% +similar so if we look at the higher mag + + + align:start position:0% +similar so if we look at the higher mag +picture again these four Images are the + + align:start position:0% +picture again these four Images are the + + + align:start position:0% +picture again these four Images are the +same area of the cells and you can if + + align:start position:0% +same area of the cells and you can if + + + align:start position:0% +same area of the cells and you can if +you look at that little bit of crud + + align:start position:0% +you look at that little bit of crud + + + align:start position:0% +you look at that little bit of crud +that's the same on all four of them + + align:start position:0% +that's the same on all four of them + + + align:start position:0% +that's the same on all four of them +there so this is the unloaded one and + + align:start position:0% +there so this is the unloaded one and + + + align:start position:0% +there so this is the unloaded one and +these were loaded from top to bottom and + + align:start position:0% +these were loaded from top to bottom and + + + align:start position:0% +these were loaded from top to bottom and +this is loaded uh to some extent that's + + align:start position:0% +this is loaded uh to some extent that's + + + align:start position:0% +this is loaded uh to some extent that's +loaded more and that's loaded more so if + + align:start position:0% +loaded more and that's loaded more so if + + + align:start position:0% +loaded more and that's loaded more so if +you look at this cell here it's got this + + align:start position:0% +you look at this cell here it's got this + + + align:start position:0% +you look at this cell here it's got this +little tear on it so you can sort of + + align:start position:0% +little tear on it so you can sort of + + + align:start position:0% +little tear on it so you can sort of +find it again if you look at that cell + + align:start position:0% +find it again if you look at that cell + + + align:start position:0% +find it again if you look at that cell +there that's what it looks like unloaded + + align:start position:0% +there that's what it looks like unloaded + + + align:start position:0% +there that's what it looks like unloaded +and here you can see see that wall there + + align:start position:0% +and here you can see see that wall there + + + align:start position:0% +and here you can see see that wall there +you can see how it's bent up so it's + + align:start position:0% +you can see how it's bent up so it's + + + align:start position:0% +you can see how it's bent up so it's +bent like the honeycomb walls and here + + align:start position:0% +bent like the honeycomb walls and here + + + align:start position:0% +bent like the honeycomb walls and here +that's bent even more and eventually it + + align:start position:0% +that's bent even more and eventually it + + + align:start position:0% +that's bent even more and eventually it +sort of has this sort of a shape here + + align:start position:0% +sort of has this sort of a shape here + + + align:start position:0% +sort of has this sort of a shape here +and you know it's formed a it's to form + + align:start position:0% +and you know it's formed a it's to form + + + align:start position:0% +and you know it's formed a it's to form +permanently it's formed one of these + + align:start position:0% +permanently it's formed one of these + + + align:start position:0% +permanently it's formed one of these +plastic hinges so it's like the aluminum + + align:start position:0% +plastic hinges so it's like the aluminum + + + align:start position:0% +plastic hinges so it's like the aluminum +Honeycombs almost that it's failed like + + align:start position:0% +Honeycombs almost that it's failed like + + + align:start position:0% +Honeycombs almost that it's failed like +that so in the balwood when we load it + + align:start position:0% +that so in the balwood when we load it + + + align:start position:0% +that so in the balwood when we load it +uh in the tangential direction we're + + align:start position:0% +uh in the tangential direction we're + + + align:start position:0% +uh in the tangential direction we're +getting bending of the cell walls and + + align:start position:0% +getting bending of the cell walls and + + + align:start position:0% +getting bending of the cell walls and +then yielding and plastic hinges forming + + align:start position:0% +then yielding and plastic hinges forming + + + align:start position:0% +then yielding and plastic hinges forming +just the same as we would in aluminum + + align:start position:0% +just the same as we would in aluminum + + + align:start position:0% +just the same as we would in aluminum +honeycomb okay are we good with that + + align:start position:0% +honeycomb okay are we good with that + + + align:start position:0% +honeycomb okay are we good with that +I'll go through the all three directions + + align:start position:0% +I'll go through the all three directions + + + align:start position:0% +I'll go through the all three directions +and then I'll write down the + + align:start position:0% +and then I'll write down the + + + align:start position:0% +and then I'll write down the +notes um so this is loading the Bala in + + align:start position:0% +notes um so this is loading the Bala in + + + align:start position:0% +notes um so this is loading the Bala in +the radial + + align:start position:0% +the radial + + + align:start position:0% +the radial +Direction and these things here are the + + align:start position:0% +Direction and these things here are the + + + align:start position:0% +Direction and these things here are the +Rays okay so we're loading it in that + + align:start position:0% +Rays okay so we're loading it in that + + + align:start position:0% +Rays okay so we're loading it in that +direction and here you see uh this also + + align:start position:0% +direction and here you see uh this also + + + align:start position:0% +direction and here you see uh this also +bending occurs but the Rays act a little + + align:start position:0% +bending occurs but the Rays act a little + + + align:start position:0% +bending occurs but the Rays act a little +bit like fiber reinforcement so the rays + + align:start position:0% +bit like fiber reinforcement so the rays + + + align:start position:0% +bit like fiber reinforcement so the rays +are a little bit stiffer and they sort + + align:start position:0% +are a little bit stiffer and they sort + + + align:start position:0% +are a little bit stiffer and they sort +of reinforce the thing a bit and this is + + align:start position:0% +of reinforce the thing a bit and this is + + + align:start position:0% +of reinforce the thing a bit and this is +the loading platin here and you can kind + + align:start position:0% +the loading platin here and you can kind + + + align:start position:0% +the loading platin here and you can kind +of see that the failure starts at the + + align:start position:0% +of see that the failure starts at the + + + align:start position:0% +of see that the failure starts at the +loading platin and as you sort of load + + align:start position:0% +loading platin and as you sort of load + + + align:start position:0% +loading platin and as you sort of load +it more it progresses in from the + + align:start position:0% +it more it progresses in from the + + + align:start position:0% +it more it progresses in from the +loading plan so we're going to look at + + align:start position:0% +loading plan so we're going to look at + + + align:start position:0% +loading plan so we're going to look at +the modeling of the BSA in the radial + + align:start position:0% +the modeling of the BSA in the radial + + + align:start position:0% +the modeling of the BSA in the radial +Direction and we're going to count for + + align:start position:0% +Direction and we're going to count for + + + align:start position:0% +Direction and we're going to count for +the Rays at least in a crude way and + + align:start position:0% +the Rays at least in a crude way and + + + align:start position:0% +the Rays at least in a crude way and +then when you load the balla in the + + align:start position:0% +then when you load the balla in the + + + align:start position:0% +then when you load the balla in the +axial Direction um initially you don't + + align:start position:0% +axial Direction um initially you don't + + + align:start position:0% +axial Direction um initially you don't +really see much happening so if one is + + align:start position:0% +really see much happening so if one is + + + align:start position:0% +really see much happening so if one is +unloaded one's down here and two is at + + align:start position:0% +unloaded one's down here and two is at + + + align:start position:0% +unloaded one's down here and two is at +this peak stress up here and really if + + align:start position:0% +this peak stress up here and really if + + + align:start position:0% +this peak stress up here and really if +you look between one and two you just + + align:start position:0% +you look between one and two you just + + + align:start position:0% +you look between one and two you just +don't see an awful lot of difference and + + align:start position:0% +don't see an awful lot of difference and + + + align:start position:0% +don't see an awful lot of difference and +that's because what you're doing is + + align:start position:0% +that's because what you're doing is + + + align:start position:0% +that's because what you're doing is +you're taking the wood and you're + + align:start position:0% +you're taking the wood and you're + + + align:start position:0% +you're taking the wood and you're +loading it this way on and it's so stiff + + align:start position:0% +loading it this way on and it's so stiff + + + align:start position:0% +loading it this way on and it's so stiff +you just don't see much deformation so + + align:start position:0% +you just don't see much deformation so + + + align:start position:0% +you just don't see much deformation so +there's not really much to see but then + + align:start position:0% +there's not really much to see but then + + + align:start position:0% +there's not really much to see but then +eventually you start something starts to + + align:start position:0% +eventually you start something starts to + + + align:start position:0% +eventually you start something starts to +fail and in this case what fails are the + + align:start position:0% +fail and in this case what fails are the + + + align:start position:0% +fail and in this case what fails are the +end caps so the Balsa would you know has + + align:start position:0% +end caps so the Balsa would you know has + + + align:start position:0% +end caps so the Balsa would you know has +these long cells here but then at the + + align:start position:0% +these long cells here but then at the + + + align:start position:0% +these long cells here but then at the +end of the cells there's little caps on + + align:start position:0% +end of the cells there's little caps on + + + align:start position:0% +end of the cells there's little caps on +the ends and the cells kind of fit + + align:start position:0% +the ends and the cells kind of fit + + + align:start position:0% +the ends and the cells kind of fit +together like that so that eventually if + + align:start position:0% +together like that so that eventually if + + + align:start position:0% +together like that so that eventually if +you keep smooshing it those end caps + + align:start position:0% +you keep smooshing it those end caps + + + align:start position:0% +you keep smooshing it those end caps +start to fail and you can see here oops + + align:start position:0% +start to fail and you can see here oops + + + align:start position:0% +start to fail and you can see here oops +wrong button here you can see how bright + + align:start position:0% +wrong button here you can see how bright + + + align:start position:0% +wrong button here you can see how bright +it gets and the cells are starting to + + align:start position:0% +it gets and the cells are starting to + + + align:start position:0% +it gets and the cells are starting to +crush together and kind of fail those + + align:start position:0% +crush together and kind of fail those + + + align:start position:0% +crush together and kind of fail those +endcaps and in fact each one of these + + align:start position:0% +endcaps and in fact each one of these + + + align:start position:0% +endcaps and in fact each one of these +serrations here if you look at say from + + align:start position:0% +serrations here if you look at say from + + + align:start position:0% +serrations here if you look at say from +that Peak up to that Peak that + + align:start position:0% +that Peak up to that Peak that + + + align:start position:0% +that Peak up to that Peak that +corresponds to a length of about the + + align:start position:0% +corresponds to a length of about the + + + align:start position:0% +corresponds to a length of about the +length of the cell or the length of the + + align:start position:0% +length of the cell or the length of the + + + align:start position:0% +length of the cell or the length of the +cell between the end caps so so in axial + + align:start position:0% +cell between the end caps so so in axial + + + align:start position:0% +cell between the end caps so so in axial +deformation you're you're just actually + + align:start position:0% +deformation you're you're just actually + + + align:start position:0% +deformation you're you're just actually +deforming the cells until you break + + align:start position:0% +deforming the cells until you break + + + align:start position:0% +deforming the cells until you break +those endcaps if you look at denser + + align:start position:0% +those endcaps if you look at denser + + + align:start position:0% +those endcaps if you look at denser +woods they fail in slightly different + + align:start position:0% +woods they fail in slightly different + + + align:start position:0% +woods they fail in slightly different +ways this is a Douglas fur which is much + + align:start position:0% +ways this is a Douglas fur which is much + + + align:start position:0% +ways this is a Douglas fur which is much +denser uh this this particular specimen + + align:start position:0% +denser uh this this particular specimen + + + align:start position:0% +denser uh this this particular specimen +the whole thing is kind of buckled over + + align:start position:0% +the whole thing is kind of buckled over + + + align:start position:0% +the whole thing is kind of buckled over +so it's not really so representative of + + align:start position:0% +so it's not really so representative of + + + align:start position:0% +so it's not really so representative of +the this the structure itself uh this is + + align:start position:0% +the this the structure itself uh this is + + + align:start position:0% +the this the structure itself uh this is +Douglas fur in radial compression and + + align:start position:0% +Douglas fur in radial compression and + + + align:start position:0% +Douglas fur in radial compression and +you can see this picture looks just like + + align:start position:0% +you can see this picture looks just like + + + align:start position:0% +you can see this picture looks just like +what I showed you for the balls of wood + + align:start position:0% +what I showed you for the balls of wood + + + align:start position:0% +what I showed you for the balls of wood +that sort of propagation of the failure + + align:start position:0% +that sort of propagation of the failure + + + align:start position:0% +that sort of propagation of the failure +and uh these are the oops these long + + align:start position:0% +and uh these are the oops these long + + + align:start position:0% +and uh these are the oops these long +things here are the Rays uh and this is + + align:start position:0% +things here are the Rays uh and this is + + + align:start position:0% +things here are the Rays uh and this is +a Norway Spruce in axial compression and + + align:start position:0% +a Norway Spruce in axial compression and + + + align:start position:0% +a Norway Spruce in axial compression and +this is fairly common in in denser Woods + + align:start position:0% +this is fairly common in in denser Woods + + + align:start position:0% +this is fairly common in in denser Woods +you get this um buckling formation and + + align:start position:0% +you get this um buckling formation and + + + align:start position:0% +you get this um buckling formation and +what happens is I think you get some + + align:start position:0% +what happens is I think you get some + + + align:start position:0% +what happens is I think you get some +yielding of the cell walls initially uh + + align:start position:0% +yielding of the cell walls initially uh + + + align:start position:0% +yielding of the cell walls initially uh +but that leads to um buckling like a + + align:start position:0% +but that leads to um buckling like a + + + align:start position:0% +but that leads to um buckling like a +plastic buckling and you can see on this + + align:start position:0% +plastic buckling and you can see on this + + + align:start position:0% +plastic buckling and you can see on this +higher mag picture down here you get + + align:start position:0% +higher mag picture down here you get + + + align:start position:0% +higher mag picture down here you get +these really small wavelength U Buckles + + align:start position:0% +these really small wavelength U Buckles + + + align:start position:0% +these really small wavelength U Buckles +in the cell wall and the two you you got + + align:start position:0% +in the cell wall and the two you you got + + + align:start position:0% +in the cell wall and the two you you got +a plane that kind of shears over itself + + align:start position:0% +a plane that kind of shears over itself + + + align:start position:0% +a plane that kind of shears over itself +and you can see in the top image that + + align:start position:0% +and you can see in the top image that + + + align:start position:0% +and you can see in the top image that +the you know this top half has sheared + + align:start position:0% +the you know this top half has sheared + + + align:start position:0% +the you know this top half has sheared +over relative to the bottom half and all + + align:start position:0% +over relative to the bottom half and all + + + align:start position:0% +over relative to the bottom half and all +the deformation is in this little band + + align:start position:0% +the deformation is in this little band + + + align:start position:0% +the deformation is in this little band +here so this you know this stuff here is + + align:start position:0% +here so this you know this stuff here is + + + align:start position:0% +here so this you know this stuff here is +all going on in that band up there okay + + align:start position:0% +all going on in that band up there okay + + + align:start position:0% +all going on in that band up there okay +so let me write down some notes about um + + align:start position:0% +so let me write down some notes about um + + + align:start position:0% +so let me write down some notes about um +how these things to form and fail uh and + + align:start position:0% +how these things to form and fail uh and + + + align:start position:0% +how these things to form and fail uh and +then we'll get to the modeling a little + + align:start position:0% +then we'll get to the modeling a little + + + align:start position:0% +then we'll get to the modeling a little +bit okay so we can say the stress strain + + align:start position:0% +bit okay so we can say the stress strain + + + align:start position:0% +bit okay so we can say the stress strain +curves resemble those for Honeycombs + + align:start position:0% + + + + align:start position:0% + +and I'll say the mechanisms of + + align:start position:0% +and I'll say the mechanisms of + + + align:start position:0% +and I'll say the mechanisms of +deformation and + + align:start position:0% +deformation and + + + align:start position:0% +deformation and +failure are most easily identified in + + align:start position:0% +failure are most easily identified in + + + align:start position:0% +failure are most easily identified in +low density Ballwood + + align:start position:0% + + + + align:start position:0% + +so for Balsa if we look at the + + align:start position:0% +so for Balsa if we look at the + + + align:start position:0% +so for Balsa if we look at the +tangential + + align:start position:0% + + + + align:start position:0% + +loading we see bending of the cell walls + + align:start position:0% +loading we see bending of the cell walls + + + align:start position:0% +loading we see bending of the cell walls +and then eventually plastic yielding + + align:start position:0% + + + + align:start position:0% + +and for radial loading the ray Act is + + align:start position:0% +and for radial loading the ray Act is + + + align:start position:0% +and for radial loading the ray Act is +reinforcing + + align:start position:0% + + + + align:start position:0% + +and for axial loading you get axial + + align:start position:0% +and for axial loading you get axial + + + align:start position:0% +and for axial loading you get axial +deformation and then failure of the endc + + align:start position:0% +deformation and then failure of the endc + + + align:start position:0% +deformation and then failure of the endc +caps + + align:start position:0% + + + + align:start position:0% + +and I'll just say failure by plastic + + align:start position:0% +and I'll just say failure by plastic + + + align:start position:0% +and I'll just say failure by plastic +buckling is also + + align:start position:0% +buckling is also + + + align:start position:0% +buckling is also +observed say in the denser + + align:start position:0% + + + + align:start position:0% + +Woods + + align:start position:0% + + + + align:start position:0% + +okay for + + align:start position:0% + + + + align:start position:0% + +okay oops where's my + + align:start position:0% + + + + align:start position:0% + +CER Heroes any right + + align:start position:0% + + + + align:start position:0% + +all right so then we can look at some + + align:start position:0% +all right so then we can look at some + + + align:start position:0% +all right so then we can look at some +data for the properties of of woods and + + align:start position:0% +data for the properties of of woods and + + + align:start position:0% +data for the properties of of woods and +these charts plot relative Young's + + align:start position:0% +these charts plot relative Young's + + + align:start position:0% +these charts plot relative Young's +modulus and relative strength against + + align:start position:0% +modulus and relative strength against + + + align:start position:0% +modulus and relative strength against +relative density so here the modulus of + + align:start position:0% +relative density so here the modulus of + + + align:start position:0% +relative density so here the modulus of +the wood is divided by the modulus of + + align:start position:0% +the wood is divided by the modulus of + + + align:start position:0% +the wood is divided by the modulus of +the solid cell wall material and here + + align:start position:0% +the solid cell wall material and here + + + align:start position:0% +the solid cell wall material and here +we've we've normalized everything by the + + align:start position:0% +we've we've normalized everything by the + + + align:start position:0% +we've we've normalized everything by the +modulus of the solid cell wall material + + align:start position:0% +modulus of the solid cell wall material + + + align:start position:0% +modulus of the solid cell wall material +in the axial Direction because the cell + + align:start position:0% +in the axial Direction because the cell + + + align:start position:0% +in the axial Direction because the cell +wall itself is + + align:start position:0% +wall itself is + + + align:start position:0% +wall itself is +anisotropic um and so here's the + + align:start position:0% +anisotropic um and so here's the + + + align:start position:0% +anisotropic um and so here's the +relative modulus and here's the relative + + align:start position:0% +relative modulus and here's the relative + + + align:start position:0% +relative modulus and here's the relative +density these are log log plots and we + + align:start position:0% +density these are log log plots and we + + + align:start position:0% +density these are log log plots and we +see that when we load the wood in the + + align:start position:0% +see that when we load the wood in the + + + align:start position:0% +see that when we load the wood in the +axial Direction the modul just linearly + + align:start position:0% +axial Direction the modul just linearly + + + align:start position:0% +axial Direction the modul just linearly +related to the density and we Lo when we + + align:start position:0% +related to the density and we Lo when we + + + align:start position:0% +related to the density and we Lo when we +load it across the grain it varies with + + align:start position:0% +load it across the grain it varies with + + + align:start position:0% +load it across the grain it varies with +the cube of the relative density so do + + align:start position:0% +the cube of the relative density so do + + + align:start position:0% +the cube of the relative density so do +you remember our little honeycomb models + + align:start position:0% +you remember our little honeycomb models + + + align:start position:0% +you remember our little honeycomb models +if I took the honeycomb and I loaded at + + align:start position:0% +if I took the honeycomb and I loaded at + + + align:start position:0% +if I took the honeycomb and I loaded at +this way it went as the cube of T over L + + align:start position:0% +this way it went as the cube of T over L + + + align:start position:0% +this way it went as the cube of T over L +and that's because of the bending and so + + align:start position:0% +and that's because of the bending and so + + + align:start position:0% +and that's because of the bending and so +the wood doesn't lie perfectly on that + + align:start position:0% +the wood doesn't lie perfectly on that + + + align:start position:0% +the wood doesn't lie perfectly on that +Cube line but it's it's fairly close and + + align:start position:0% +Cube line but it's it's fairly close and + + + align:start position:0% +Cube line but it's it's fairly close and +then similarly if we took the honeycomb + + align:start position:0% +then similarly if we took the honeycomb + + + align:start position:0% +then similarly if we took the honeycomb +and we loaded it this way on and it + + align:start position:0% +and we loaded it this way on and it + + + align:start position:0% +and we loaded it this way on and it +deformed actually the modulus depended + + align:start position:0% +deformed actually the modulus depended + + + align:start position:0% +deformed actually the modulus depended +linearly on the um density so you get + + align:start position:0% +linearly on the um density so you get + + + align:start position:0% +linearly on the um density so you get +the same kind of relationships there and + + align:start position:0% +the same kind of relationships there and + + + align:start position:0% +the same kind of relationships there and +then if you look at the strength the + + align:start position:0% +then if you look at the strength the + + + align:start position:0% +then if you look at the strength the +strength along the grain goes linearly + + align:start position:0% +strength along the grain goes linearly + + + align:start position:0% +strength along the grain goes linearly +uh and the strength across the grain + + align:start position:0% +uh and the strength across the grain + + + align:start position:0% +uh and the strength across the grain +goes with the square and uh we'll see + + align:start position:0% +goes with the square and uh we'll see + + + align:start position:0% +goes with the square and uh we'll see +when we get to the modeling in a minute + + align:start position:0% +when we get to the modeling in a minute + + + align:start position:0% +when we get to the modeling in a minute +that if we loaded say an aluminum + + align:start position:0% +that if we loaded say an aluminum + + + align:start position:0% +that if we loaded say an aluminum +honeycomb this way on the strength would + + align:start position:0% +honeycomb this way on the strength would + + + align:start position:0% +honeycomb this way on the strength would +go linearly with the density if we're + + align:start position:0% +go linearly with the density if we're + + + align:start position:0% +go linearly with the density if we're +just yielding the cell walls and if we + + align:start position:0% +just yielding the cell walls and if we + + + align:start position:0% +just yielding the cell walls and if we +loaded it this way on it went as the + + align:start position:0% +loaded it this way on it went as the + + + align:start position:0% +loaded it this way on it went as the +square of T overl so it these things + + align:start position:0% +square of T overl so it these things + + + align:start position:0% +square of T overl so it these things +kind of correspond and you can see the + + align:start position:0% +kind of correspond and you can see the + + + align:start position:0% +kind of correspond and you can see the +structure of the wood is a lot more + + align:start position:0% +structure of the wood is a lot more + + + align:start position:0% +structure of the wood is a lot more +complicated than just a simple honeycomb + + align:start position:0% +complicated than just a simple honeycomb + + + align:start position:0% +complicated than just a simple honeycomb +and so these models are sort of first + + align:start position:0% +and so these models are sort of first + + + align:start position:0% +and so these models are sort of first +order and they're fairly crude they + + align:start position:0% +order and they're fairly crude they + + + align:start position:0% +order and they're fairly crude they +don't try to capture every detail of the + + align:start position:0% +don't try to capture every detail of the + + + align:start position:0% +don't try to capture every detail of the +wood structure uh but they can give you + + align:start position:0% +wood structure uh but they can give you + + + align:start position:0% +wood structure uh but they can give you +a a sense of where the wood properties + + align:start position:0% +a a sense of where the wood properties + + + align:start position:0% +a a sense of where the wood properties +are coming from so let me just write + + align:start position:0% +are coming from so let me just write + + + align:start position:0% +are coming from so let me just write +down some of these + + align:start position:0% + + + + align:start position:0% + +observations so the data for the wood + + align:start position:0% + + + + align:start position:0% + +the modulus along the grain goes + + align:start position:0% +the modulus along the grain goes + + + align:start position:0% +the modulus along the grain goes +linearly with + + align:start position:0% + + + + align:start position:0% + +density it goes more or less as the cube + + align:start position:0% +density it goes more or less as the cube + + + align:start position:0% +density it goes more or less as the cube +for loading in the tangential Direction + + align:start position:0% +for loading in the tangential Direction + + + align:start position:0% +for loading in the tangential Direction +and The radial direction is somewhat + + align:start position:0% +and The radial direction is somewhat + + + align:start position:0% +and The radial direction is somewhat +stiffer than that + + align:start position:0% + + + + align:start position:0% + +the strength in the axial + + align:start position:0% +the strength in the axial + + + align:start position:0% +the strength in the axial +Direction goes linearly with the + + align:start position:0% + + + + align:start position:0% + +density and the + + align:start position:0% + + + + align:start position:0% + +strength across the grain goes with the + + align:start position:0% +strength across the grain goes with the + + + align:start position:0% +strength across the grain goes with the +square of the density + + align:start position:0% + + + + align:start position:0% + +and then there's data for the poson + + align:start position:0% +and then there's data for the poson + + + align:start position:0% +and then there's data for the poson +ratios + + align:start position:0% +ratios + + + align:start position:0% +ratios +too so let me just write them down + + align:start position:0% + + + + align:start position:0% + +so the modeling based on the honeycomb + + align:start position:0% +so the modeling based on the honeycomb + + + align:start position:0% +so the modeling based on the honeycomb +is sort of a simplified + + align:start position:0% + + + + align:start position:0% + +model that gives you kind of a first + + align:start position:0% +model that gives you kind of a first + + + align:start position:0% +model that gives you kind of a first +ordered description of the + + align:start position:0% +ordered description of the + + + align:start position:0% +ordered description of the +behavior and it doesn't really attempt + + align:start position:0% +behavior and it doesn't really attempt + + + align:start position:0% +behavior and it doesn't really attempt +to capture all the details of the uh + + align:start position:0% +to capture all the details of the uh + + + align:start position:0% +to capture all the details of the uh +softwood and hardwood + + align:start position:0% + + + + align:start position:0% + +structure and in the equations I'm going + + align:start position:0% +structure and in the equations I'm going + + + align:start position:0% +structure and in the equations I'm going +to take the cell wall properties along + + align:start position:0% +to take the cell wall properties along + + + align:start position:0% +to take the cell wall properties along +the grain + + align:start position:0% +the grain + + + align:start position:0% +the grain +or along the axial + + align:start position:0% + + + + align:start position:0% + +Direction and we're going to have a + + align:start position:0% +Direction and we're going to have a + + + align:start position:0% +Direction and we're going to have a +bunch of constants that describe the + + align:start position:0% +bunch of constants that describe the + + + align:start position:0% +bunch of constants that describe the +cell geometry and those constants are + + align:start position:0% +cell geometry and those constants are + + + align:start position:0% +cell geometry and those constants are +also going to reflect the cell wall an + + align:start position:0% +also going to reflect the cell wall an + + + align:start position:0% +also going to reflect the cell wall an +isotropy and an an isotropy + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +so we can model the wood structure as + + align:start position:0% +so we can model the wood structure as + + + align:start position:0% +so we can model the wood structure as +something that's a bit more of a + + align:start position:0% +something that's a bit more of a + + + align:start position:0% +something that's a bit more of a +simplified thing just like this and we + + align:start position:0% +simplified thing just like this and we + + + align:start position:0% +simplified thing just like this and we +say we've got cells that are roughly + + align:start position:0% +say we've got cells that are roughly + + + align:start position:0% +say we've got cells that are roughly +hexagonal and then we've got some cells + + align:start position:0% +hexagonal and then we've got some cells + + + align:start position:0% +hexagonal and then we've got some cells +that are more or less rectangular that + + align:start position:0% +that are more or less rectangular that + + + align:start position:0% +that are more or less rectangular that +are the ray cells and if you look at + + align:start position:0% +are the ray cells and if you look at + + + align:start position:0% +are the ray cells and if you look at +lots of micrographs you can get some + + align:start position:0% +lots of micrographs you can get some + + + align:start position:0% +lots of micrographs you can get some +idea what the dimensions of the cells + + align:start position:0% +idea what the dimensions of the cells + + + align:start position:0% +idea what the dimensions of the cells +are and these Dimensions were measured + + align:start position:0% +are and these Dimensions were measured + + + align:start position:0% +are and these Dimensions were measured +for a particular density of bolts of + + align:start position:0% + + + + align:start position:0% + +wood so if we look at the linear elastic + + align:start position:0% +wood so if we look at the linear elastic + + + align:start position:0% +wood so if we look at the linear elastic +modui we can start off with a tangential + + align:start position:0% + + + + align:start position:0% + +loading and if we have the tangential + + align:start position:0% +loading and if we have the tangential + + + align:start position:0% +loading and if we have the tangential +loading we can model it as a honey comb + + align:start position:0% +loading we can model it as a honey comb + + + align:start position:0% +loading we can model it as a honey comb +loaded in the plane and we get cell wall + + align:start position:0% + + + + align:start position:0% + +bending and from the cell wall bending + + align:start position:0% +bending and from the cell wall bending + + + align:start position:0% +bending and from the cell wall bending +and the honeycomb model you would get + + align:start position:0% +and the honeycomb model you would get + + + align:start position:0% +and the honeycomb model you would get +that the tangential modulus varies with + + align:start position:0% +that the tangential modulus varies with + + + align:start position:0% +that the tangential modulus varies with +the relative density + + align:start position:0% +the relative density + + + align:start position:0% +the relative density +cubed and the the structure is not quite + + align:start position:0% +cubed and the the structure is not quite + + + align:start position:0% +cubed and the the structure is not quite +that simple there's Ray cells there's + + align:start position:0% +that simple there's Ray cells there's + + + align:start position:0% +that simple there's Ray cells there's +end caps and they act to stiffen it a + + align:start position:0% +end caps and they act to stiffen it a + + + align:start position:0% +end caps and they act to stiffen it a +little bit and the data lie a little bit + + align:start position:0% +little bit and the data lie a little bit + + + align:start position:0% +little bit and the data lie a little bit +above this line + + align:start position:0% + + + + align:start position:0% + +then if we look at the radial loading + + align:start position:0% +then if we look at the radial loading + + + align:start position:0% +then if we look at the radial loading +the the Rays kind of line up with the + + align:start position:0% +the the Rays kind of line up with the + + + align:start position:0% +the the Rays kind of line up with the +radial Direction and the Rays act as + + align:start position:0% +radial Direction and the Rays act as + + + align:start position:0% +radial Direction and the Rays act as +reinforcing plates and so you can just + + align:start position:0% +reinforcing plates and so you can just + + + align:start position:0% +reinforcing plates and so you can just +use kind of an upper bound Composites + + align:start position:0% +use kind of an upper bound Composites + + + align:start position:0% +use kind of an upper bound Composites +idea to get the + + align:start position:0% + + + + align:start position:0% + +modulus and the Rays tend to be a bit + + align:start position:0% +modulus and the Rays tend to be a bit + + + align:start position:0% +modulus and the Rays tend to be a bit +denser than the fibers + + align:start position:0% + + + + align:start position:0% + +so if I say VR is the volume fraction of + + align:start position:0% + + + + align:start position:0% + +rays and R is the ratio of the relative + + align:start position:0% +rays and R is the ratio of the relative + + + align:start position:0% +rays and R is the ratio of the relative +density of the Rays compared to the + + align:start position:0% +density of the Rays compared to the + + + align:start position:0% +density of the Rays compared to the +fibers so it's row over row s for the + + align:start position:0% +fibers so it's row over row s for the + + + align:start position:0% +fibers so it's row over row s for the +Rays divided by row over row + + align:start position:0% +Rays divided by row over row + + + align:start position:0% +Rays divided by row over row +s for the + + align:start position:0% +s for the + + + align:start position:0% +s for the +fibers and that varies a little bit from + + align:start position:0% +fibers and that varies a little bit from + + + align:start position:0% +fibers and that varies a little bit from +one species to another one specimen to + + align:start position:0% +one species to another one specimen to + + + align:start position:0% +one species to another one specimen to +another but it's something a little over + + align:start position:0% +another but it's something a little over + + + align:start position:0% +another but it's something a little over +one something between one and two then I + + align:start position:0% +one something between one and two then I + + + align:start position:0% +one something between one and two then I +can say the modulus in the radial + + align:start position:0% +can say the modulus in the radial + + + align:start position:0% +can say the modulus in the radial +direction is the volume fraction of the + + align:start position:0% +direction is the volume fraction of the + + + align:start position:0% +direction is the volume fraction of the +Rays time R cubed time the tangential + + align:start position:0% +Rays time R cubed time the tangential + + + align:start position:0% +Rays time R cubed time the tangential +modulus plus 1 minus the volume fraction + + align:start position:0% +modulus plus 1 minus the volume fraction + + + align:start position:0% +modulus plus 1 minus the volume fraction +of + + align:start position:0% +of + + + align:start position:0% +of +rays times the tangential modulus and + + align:start position:0% +rays times the tangential modulus and + + + align:start position:0% +rays times the tangential modulus and +that works out to be about 1.5 + + align:start position:0% +that works out to be about 1.5 + + + align:start position:0% +that works out to be about 1.5 +* the tangential modulus I wanted to + + align:start position:0% +* the tangential modulus I wanted to + + + align:start position:0% +* the tangential modulus I wanted to +work this out in terms of the tangential + + align:start position:0% +work this out in terms of the tangential + + + align:start position:0% +work this out in terms of the tangential +modulus so I've put this in terms of the + + align:start position:0% +modulus so I've put this in terms of the + + + align:start position:0% +modulus so I've put this in terms of the +tangential modulus in the first term + + align:start position:0% +tangential modulus in the first term + + + align:start position:0% +tangential modulus in the first term +there so we get that the radial modulus + + align:start position:0% +there so we get that the radial modulus + + + align:start position:0% +there so we get that the radial modulus +is slightly larger than the tangential + + align:start position:0% +is slightly larger than the tangential + + + align:start position:0% +is slightly larger than the tangential +but also goes roughly as the cube of the + + align:start position:0% +but also goes roughly as the cube of the + + + align:start position:0% +but also goes roughly as the cube of the +density + + align:start position:0% + + + + align:start position:0% + +and then for the axial loading we just + + align:start position:0% +and then for the axial loading we just + + + align:start position:0% +and then for the axial loading we just +have axial deformation in the cell wall + + align:start position:0% +have axial deformation in the cell wall + + + align:start position:0% +have axial deformation in the cell wall +and the and the young modules just + + align:start position:0% +and the and the young modules just + + + align:start position:0% +and the and the young modules just +varies linearly with the density + + align:start position:0% + + + + align:start position:0% + +so these are kind of simple models but + + align:start position:0% +so these are kind of simple models but + + + align:start position:0% +so these are kind of simple models but +they kind of explain to first order the + + align:start position:0% +they kind of explain to first order the + + + align:start position:0% +they kind of explain to first order the +density dependence of the wood moduli + + align:start position:0% +density dependence of the wood moduli + + + align:start position:0% +density dependence of the wood moduli +and the anisotropy + + align:start position:0% + + + + align:start position:0% + +so it's kind of nice cuz they're fairly + + align:start position:0% +so it's kind of nice cuz they're fairly + + + align:start position:0% +so it's kind of nice cuz they're fairly +simple models and that gives you kind of + + align:start position:0% +simple models and that gives you kind of + + + align:start position:0% +simple models and that gives you kind of +a big picture so if you wanted to know + + align:start position:0% +a big picture so if you wanted to know + + + align:start position:0% +a big picture so if you wanted to know +the modulus of a particular piece of + + align:start position:0% +the modulus of a particular piece of + + + align:start position:0% +the modulus of a particular piece of +wood this probably isn't the best way to + + align:start position:0% +wood this probably isn't the best way to + + + align:start position:0% +wood this probably isn't the best way to +figure it out but if you wanted to kind + + align:start position:0% +figure it out but if you wanted to kind + + + align:start position:0% +figure it out but if you wanted to kind +of compare how the woods behave in + + align:start position:0% +of compare how the woods behave in + + + align:start position:0% +of compare how the woods behave in +general and how does the density affect + + align:start position:0% +general and how does the density affect + + + align:start position:0% +general and how does the density affect +the properties and why are they an + + align:start position:0% +the properties and why are they an + + + align:start position:0% +the properties and why are they an +isotropic this is a pretty good way to + + align:start position:0% +isotropic this is a pretty good way to + + + align:start position:0% +isotropic this is a pretty good way to +do it + + align:start position:0% + + + + align:start position:0% + +we could also look at the puin ratios + + align:start position:0% +we could also look at the puin ratios + + + align:start position:0% +we could also look at the puin ratios +and just because I didn't want to write + + align:start position:0% +and just because I didn't want to write + + + align:start position:0% +and just because I didn't want to write +them down again I've just left on what + + align:start position:0% +them down again I've just left on what + + + align:start position:0% +them down again I've just left on what +the data were down here but let me just + + align:start position:0% +the data were down here but let me just + + + align:start position:0% +the data were down here but let me just +write what the model would give + + align:start position:0% +write what the model would give + + + align:start position:0% +write what the model would give +us uh for new RT and new + + align:start position:0% +us uh for new RT and new + + + align:start position:0% +us uh for new RT and new +TR the model would give us one if we had + + align:start position:0% +TR the model would give us one if we had + + + align:start position:0% +TR the model would give us one if we had +regular hexagonal cells uh and these are + + align:start position:0% +regular hexagonal cells uh and these are + + + align:start position:0% +regular hexagonal cells uh and these are +the values we get here this might be you + + align:start position:0% +the values we get here this might be you + + + align:start position:0% +the values we get here this might be you +know 6.7 would be a typical value + + align:start position:0% +know 6.7 would be a typical value + + + align:start position:0% +know 6.7 would be a typical value +somewhere around 04 in there so they're + + align:start position:0% +somewhere around 04 in there so they're + + + align:start position:0% +somewhere around 04 in there so they're +not quite one but they're close to it + + align:start position:0% +not quite one but they're close to it + + + align:start position:0% +not quite one but they're close to it +and I think uh the reason they're a + + align:start position:0% +and I think uh the reason they're a + + + align:start position:0% +and I think uh the reason they're a +little less is because the Rays and the + + align:start position:0% +little less is because the Rays and the + + + align:start position:0% +little less is because the Rays and the +end caps provide some constraint and you + + align:start position:0% +end caps provide some constraint and you + + + align:start position:0% +end caps provide some constraint and you +don't you know if you have the honeycomb + + align:start position:0% +don't you know if you have the honeycomb + + + align:start position:0% +don't you know if you have the honeycomb +if I just had these cells and I I + + align:start position:0% +if I just had these cells and I I + + + align:start position:0% +if I just had these cells and I I +squeeze it like this these guys can move + + align:start position:0% +squeeze it like this these guys can move + + + align:start position:0% +squeeze it like this these guys can move +out and if it's a regular hexagonal + + align:start position:0% +out and if it's a regular hexagonal + + + align:start position:0% +out and if it's a regular hexagonal +honeycomb The Strain that I'm applying + + align:start position:0% +honeycomb The Strain that I'm applying + + + align:start position:0% +honeycomb The Strain that I'm applying +here is equal to the strain going out + + align:start position:0% +here is equal to the strain going out + + + align:start position:0% +here is equal to the strain going out +that way but if I have Rays this way + + align:start position:0% +that way but if I have Rays this way + + + align:start position:0% +that way but if I have Rays this way +that sort of constrain it or encaps uh + + align:start position:0% +that sort of constrain it or encaps uh + + + align:start position:0% +that sort of constrain it or encaps uh +it means that the plus ratio is going to + + align:start position:0% +it means that the plus ratio is going to + + + align:start position:0% +it means that the plus ratio is going to +be a little bit + + align:start position:0% +be a little bit + + + align:start position:0% +be a little bit +less so I'll just say constraining + + align:start position:0% +less so I'll just say constraining + + + align:start position:0% +less so I'll just say constraining +effect of the end caps and + + align:start position:0% +effect of the end caps and + + + align:start position:0% +effect of the end caps and +Rays constraining + + align:start position:0% + + + + align:start position:0% + +then for + + align:start position:0% +then for + + + align:start position:0% +then for +new ra and new + + align:start position:0% +new ra and new + + + align:start position:0% +new ra and new +ta the model + + align:start position:0% +ta the model + + + align:start position:0% +ta the model +says the value we would get be zero and + + align:start position:0% +says the value we would get be zero and + + + align:start position:0% +says the value we would get be zero and +these are pretty close to zero they're + + align:start position:0% +these are pretty close to zero they're + + + align:start position:0% +these are pretty close to zero they're +not quite zero but pretty + + align:start position:0% +not quite zero but pretty + + + align:start position:0% +not quite zero but pretty +close and then the last + + align:start position:0% +close and then the last + + + align:start position:0% +close and then the last +pair new a + + align:start position:0% +pair new a + + + align:start position:0% +pair new a +r and new a + + align:start position:0% +r and new a + + + align:start position:0% +r and new a +t the model says that we would get new + + align:start position:0% +t the model says that we would get new + + + align:start position:0% +t the model says that we would get new +of the + + align:start position:0% + + + + align:start position:0% + +solid and the data is close to + + align:start position:0% +solid and the data is close to + + + align:start position:0% +solid and the data is close to +0.4 which you might expect would be + + align:start position:0% +0.4 which you might expect would be + + + align:start position:0% +0.4 which you might expect would be +about the new of the solid so again + + align:start position:0% +about the new of the solid so again + + + align:start position:0% +about the new of the solid so again +there's some variation in the proon + + align:start position:0% +there's some variation in the proon + + + align:start position:0% +there's some variation in the proon +ratios not all just one number but you + + align:start position:0% +ratios not all just one number but you + + + align:start position:0% +ratios not all just one number but you +can see you know these these ones here + + align:start position:0% +can see you know these these ones here + + + align:start position:0% +can see you know these these ones here +are about zero and that's roughly what + + align:start position:0% +are about zero and that's roughly what + + + align:start position:0% +are about zero and that's roughly what +the model says these ones here are + + align:start position:0% +the model says these ones here are + + + align:start position:0% +the model says these ones here are +closer to one uh and then these ones + + align:start position:0% +closer to one uh and then these ones + + + align:start position:0% +closer to one uh and then these ones +here are closer to what you might expect + + align:start position:0% +here are closer to what you might expect + + + align:start position:0% +here are closer to what you might expect +for a solid material so it gives you the + + align:start position:0% +for a solid material so it gives you the + + + align:start position:0% +for a solid material so it gives you the +kind of General general idea are we good + + align:start position:0% +kind of General general idea are we good + + + align:start position:0% +kind of General general idea are we good +we're good + + align:start position:0% + + + + align:start position:0% + +yeah so we can do a similar thing for + + align:start position:0% +yeah so we can do a similar thing for + + + align:start position:0% +yeah so we can do a similar thing for +the compressive + + align:start position:0% + + + + align:start position:0% + +strength uh so for tangential loading we + + align:start position:0% +strength uh so for tangential loading we + + + align:start position:0% +strength uh so for tangential loading we +get plas the hinges forming in the men + + align:start position:0% +get plas the hinges forming in the men + + + align:start position:0% +get plas the hinges forming in the men +cell + + align:start position:0% + + + + align:start position:0% + +walls just like in an aluminum + + align:start position:0% + + + + align:start position:0% + +honeycomb and we get that the + + align:start position:0% +honeycomb and we get that the + + + align:start position:0% +honeycomb and we get that the +strength over the cell wall + + align:start position:0% +strength over the cell wall + + + align:start position:0% +strength over the cell wall +strength goes into the relative density + + align:start position:0% +strength goes into the relative density + + + align:start position:0% +strength goes into the relative density +squared so just like the honeycomb for + + align:start position:0% +squared so just like the honeycomb for + + + align:start position:0% +squared so just like the honeycomb for +the radial loading we can do the + + align:start position:0% +the radial loading we can do the + + + align:start position:0% +the radial loading we can do the +Composites thing + + align:start position:0% + + + + align:start position:0% + +again so we can say the strength in the + + align:start position:0% +again so we can say the strength in the + + + align:start position:0% +again so we can say the strength in the +radial direction is about equal to the + + align:start position:0% +radial direction is about equal to the + + + align:start position:0% +radial direction is about equal to the +volume fraction of rays time r squared + + align:start position:0% +volume fraction of rays time r squared + + + align:start position:0% +volume fraction of rays time r squared +time the tangential strength plus 1 + + align:start position:0% +time the tangential strength plus 1 + + + align:start position:0% +time the tangential strength plus 1 +minus the volume fraction of rays time + + align:start position:0% +minus the volume fraction of rays time + + + align:start position:0% +minus the volume fraction of rays time +the tangential strength and for + + align:start position:0% +the tangential strength and for + + + align:start position:0% +the tangential strength and for +Balsa we have some values here VR is + + align:start position:0% +Balsa we have some values here VR is + + + align:start position:0% +Balsa we have some values here VR is +about equal to one or + + align:start position:0% +about equal to one or + + + align:start position:0% +about equal to one or +0.14 R is about equal to two and so the + + align:start position:0% +0.14 R is about equal to two and so the + + + align:start position:0% +0.14 R is about equal to two and so the +radial + + align:start position:0% +radial + + + align:start position:0% +radial +strength is about equal to 1.4 * the + + align:start position:0% +strength is about equal to 1.4 * the + + + align:start position:0% +strength is about equal to 1.4 * the +tangential and in higher density Woods + + align:start position:0% +tangential and in higher density Woods + + + align:start position:0% +tangential and in higher density Woods +the value of R is a little bit smaller + + align:start position:0% +the value of R is a little bit smaller + + + align:start position:0% +the value of R is a little bit smaller +and in general the radial strength is a + + align:start position:0% +and in general the radial strength is a + + + align:start position:0% +and in general the radial strength is a +bit larger than the tangential and both + + align:start position:0% +bit larger than the tangential and both + + + align:start position:0% +bit larger than the tangential and both +depend on the density squared + + align:start position:0% + + + + align:start position:0% + +okay and + + align:start position:0% +okay and + + + align:start position:0% +okay and +then and then for axial + + align:start position:0% +then and then for axial + + + align:start position:0% +then and then for axial +loading if the failure is initiated by + + align:start position:0% +loading if the failure is initiated by + + + align:start position:0% +loading if the failure is initiated by +yielding the cell walls then the actual + + align:start position:0% +yielding the cell walls then the actual + + + align:start position:0% +yielding the cell walls then the actual +strength is just going to depend + + align:start position:0% +strength is just going to depend + + + align:start position:0% +strength is just going to depend +linearly on the + + align:start position:0% + + + + align:start position:0% + +density okay + + align:start position:0% +density okay + + + align:start position:0% +density okay +so the idea with these models isn't that + + align:start position:0% +so the idea with these models isn't that + + + align:start position:0% +so the idea with these models isn't that +they kind of describe a particular um + + align:start position:0% +they kind of describe a particular um + + + align:start position:0% +they kind of describe a particular um +you know particular piece of wood + + align:start position:0% +you know particular piece of wood + + + align:start position:0% +you know particular piece of wood +exactly it's more that it gives you a + + align:start position:0% +exactly it's more that it gives you a + + + align:start position:0% +exactly it's more that it gives you a +general picture of how the cells are + + align:start position:0% +general picture of how the cells are + + + align:start position:0% +general picture of how the cells are +deforming and failing and how the + + align:start position:0% +deforming and failing and how the + + + align:start position:0% +deforming and failing and how the +properties scale with density and why + + align:start position:0% +properties scale with density and why + + + align:start position:0% +properties scale with density and why +the woods an isotropic + + align:start position:0% + + + + align:start position:0% + +are we good y caught up okay so there's + + align:start position:0% +are we good y caught up okay so there's + + + align:start position:0% +are we good y caught up okay so there's +a couple more sort of interesting things + + align:start position:0% +a couple more sort of interesting things + + + align:start position:0% +a couple more sort of interesting things +we can do uh with looking at the wood + + align:start position:0% +we can do uh with looking at the wood + + + align:start position:0% +we can do uh with looking at the wood +properties so we've been talking about + + align:start position:0% +properties so we've been talking about + + + align:start position:0% +properties so we've been talking about +how to model the cellular structure but + + align:start position:0% +how to model the cellular structure but + + + align:start position:0% +how to model the cellular structure but +people have also looked at how to model + + align:start position:0% +people have also looked at how to model + + + align:start position:0% +people have also looked at how to model +the cell wall as a fiber composite and + + align:start position:0% +the cell wall as a fiber composite and + + + align:start position:0% +the cell wall as a fiber composite and +this plot and the next one kind of show + + align:start position:0% +this plot and the next one kind of show + + + align:start position:0% +this plot and the next one kind of show +you how you can can combine all of that + + align:start position:0% +you how you can can combine all of that + + + align:start position:0% +you how you can can combine all of that +together so remember I said the modulus + + align:start position:0% +together so remember I said the modulus + + + align:start position:0% +together so remember I said the modulus +of the cellulose was around 140 gigap + + align:start position:0% +of the cellulose was around 140 gigap + + + align:start position:0% +of the cellulose was around 140 gigap +pascals so here's the modulus of the + + align:start position:0% +pascals so here's the modulus of the + + + align:start position:0% +pascals so here's the modulus of the +cellulose um at least the crystalline + + align:start position:0% +cellulose um at least the crystalline + + + align:start position:0% +cellulose um at least the crystalline +part of the cellulose plotted in that + + align:start position:0% +part of the cellulose plotted in that + + + align:start position:0% +part of the cellulose plotted in that +little envelope there the ligan and the + + align:start position:0% +little envelope there the ligan and the + + + align:start position:0% +little envelope there the ligan and the +hemicellulose have a modulus around two + + align:start position:0% +hemicellulose have a modulus around two + + + align:start position:0% +hemicellulose have a modulus around two +or 3 gigap Pascal so it's down there and + + align:start position:0% +or 3 gigap Pascal so it's down there and + + + align:start position:0% +or 3 gigap Pascal so it's down there and +if you made Composites with cellulose + + align:start position:0% +if you made Composites with cellulose + + + align:start position:0% +if you made Composites with cellulose +fibers in ligan and hemicellulose Matrix + + align:start position:0% +fibers in ligan and hemicellulose Matrix + + + align:start position:0% +fibers in ligan and hemicellulose Matrix +those Composites would have a modulus + + align:start position:0% +those Composites would have a modulus + + + align:start position:0% +those Composites would have a modulus +that fell in this envelope here they've + + align:start position:0% +that fell in this envelope here they've + + + align:start position:0% +that fell in this envelope here they've +got to be in between those two limits + + align:start position:0% +got to be in between those two limits + + + align:start position:0% +got to be in between those two limits +right the modulus have to be between + + align:start position:0% +right the modulus have to be between + + + align:start position:0% +right the modulus have to be between +those two limits the density have to be + + align:start position:0% +those two limits the density have to be + + + align:start position:0% +those two limits the density have to be +within the densities of the + + align:start position:0% +within the densities of the + + + align:start position:0% +within the densities of the +constituents and if you look at the + + align:start position:0% +constituents and if you look at the + + + align:start position:0% +constituents and if you look at the +modulus of the wood cell wall it lies in + + align:start position:0% +modulus of the wood cell wall it lies in + + + align:start position:0% +modulus of the wood cell wall it lies in +this envelope here the along the grain + + align:start position:0% +this envelope here the along the grain + + + align:start position:0% +this envelope here the along the grain +would be here and then across the grain + + align:start position:0% +would be here and then across the grain + + + align:start position:0% +would be here and then across the grain +is further down here so the cell wall + + align:start position:0% +is further down here so the cell wall + + + align:start position:0% +is further down here so the cell wall +modulus is in here and then if you take + + align:start position:0% +modulus is in here and then if you take + + + align:start position:0% +modulus is in here and then if you take +that cell wall and you make it into the + + align:start position:0% +that cell wall and you make it into the + + + align:start position:0% +that cell wall and you make it into the +honeycomb type material that wood is if + + align:start position:0% +honeycomb type material that wood is if + + + align:start position:0% +honeycomb type material that wood is if +you load it along the grain you're going + + align:start position:0% +you load it along the grain you're going + + + align:start position:0% +you load it along the grain you're going +to get this linear dependence of U + + align:start position:0% +to get this linear dependence of U + + + align:start position:0% +to get this linear dependence of U +modulus on density and if you load it + + align:start position:0% +modulus on density and if you load it + + + align:start position:0% +modulus on density and if you load it +across the Grain in the radial or the + + align:start position:0% +across the Grain in the radial or the + + + align:start position:0% +across the Grain in the radial or the +tangential Direction you're going to get + + align:start position:0% +tangential Direction you're going to get + + + align:start position:0% +tangential Direction you're going to get +this Cube dependence here so here's a + + align:start position:0% +this Cube dependence here so here's a + + + align:start position:0% +this Cube dependence here so here's a +set of data for different Woods of + + align:start position:0% +set of data for different Woods of + + + align:start position:0% +set of data for different Woods of +different densities and that envelope + + align:start position:0% +different densities and that envelope + + + align:start position:0% +different densities and that envelope +kind of um encompasses all of them uh + + align:start position:0% +kind of um encompasses all of them uh + + + align:start position:0% +kind of um encompasses all of them uh +but if you if you look at the slope of + + align:start position:0% +but if you if you look at the slope of + + + align:start position:0% +but if you if you look at the slope of +that data it's roughly equal to a slope + + align:start position:0% +that data it's roughly equal to a slope + + + align:start position:0% +that data it's roughly equal to a slope +of one and so it corresponds to that + + align:start position:0% +of one and so it corresponds to that + + + align:start position:0% +of one and so it corresponds to that +equation there and similarly here's a a + + align:start position:0% +equation there and similarly here's a a + + + align:start position:0% +equation there and similarly here's a a +set of data for different species of + + align:start position:0% +set of data for different species of + + + align:start position:0% +set of data for different species of +woods of different densities loaded + + align:start position:0% +woods of different densities loaded + + + align:start position:0% +woods of different densities loaded +perpendicular to the Grain and they lie + + align:start position:0% +perpendicular to the Grain and they lie + + + align:start position:0% +perpendicular to the Grain and they lie +on a line that has more or less a slope + + align:start position:0% +on a line that has more or less a slope + + + align:start position:0% +on a line that has more or less a slope +of three and this set of data here along + + align:start position:0% +of three and this set of data here along + + + align:start position:0% +of three and this set of data here along +the grain intersects the wood cell wall + + align:start position:0% +the grain intersects the wood cell wall + + + align:start position:0% +the grain intersects the wood cell wall +sort of towards the top of that envelope + + align:start position:0% +sort of towards the top of that envelope + + + align:start position:0% +sort of towards the top of that envelope +and this set of data here intersects + + align:start position:0% +and this set of data here intersects + + + align:start position:0% +and this set of data here intersects +closer to the bottom of that set of that + + align:start position:0% +closer to the bottom of that set of that + + + align:start position:0% +closer to the bottom of that set of that +envelope for the C wall material so this + + align:start position:0% +envelope for the C wall material so this + + + align:start position:0% +envelope for the C wall material so this +gives a way of sort of putting + + align:start position:0% +gives a way of sort of putting + + + align:start position:0% +gives a way of sort of putting +everything together on one plot the cell + + align:start position:0% +everything together on one plot the cell + + + align:start position:0% +everything together on one plot the cell +wall as well as the cellular structure + + align:start position:0% +wall as well as the cellular structure + + + align:start position:0% +wall as well as the cellular structure +so that plot does it for the modulus and + + align:start position:0% +so that plot does it for the modulus and + + + align:start position:0% +so that plot does it for the modulus and +you can do the same kind of thing for + + align:start position:0% +you can do the same kind of thing for + + + align:start position:0% +you can do the same kind of thing for +the strength here's the cellulose up + + align:start position:0% +the strength here's the cellulose up + + + align:start position:0% +the strength here's the cellulose up +here here's the lignin down there here's + + align:start position:0% +here here's the lignin down there here's + + + align:start position:0% +here here's the lignin down there here's +the wood cell wall but composite made + + align:start position:0% +the wood cell wall but composite made + + + align:start position:0% +the wood cell wall but composite made +from those two and then here's data for + + align:start position:0% +from those two and then here's data for + + + align:start position:0% +from those two and then here's data for +different kinds of woods loaded along + + align:start position:0% +different kinds of woods loaded along + + + align:start position:0% +different kinds of woods loaded along +the Grain and for loaded across the + + align:start position:0% +the Grain and for loaded across the + + + align:start position:0% +the Grain and for loaded across the +grain so it gives you a way of kind of + + align:start position:0% +grain so it gives you a way of kind of + + + align:start position:0% +grain so it gives you a way of kind of +putting all of this modeling into one + + align:start position:0% +putting all of this modeling into one + + + align:start position:0% +putting all of this modeling into one +set of plots uh so let me just write a + + align:start position:0% +set of plots uh so let me just write a + + + align:start position:0% +set of plots uh so let me just write a +couple of little things about + + align:start position:0% + + + + align:start position:0% + +that so we could say you could model the + + align:start position:0% +that so we could say you could model the + + + align:start position:0% +that so we could say you could model the +cell wall as a fiber composite + + align:start position:0% + + + + align:start position:0% + +and you can use the composite upper and + + align:start position:0% +and you can use the composite upper and + + + align:start position:0% +and you can use the composite upper and +lower + + align:start position:0% +lower + + + align:start position:0% +lower +bounds to give an envelope + + align:start position:0% + + + + align:start position:0% + +and then you can also + + align:start position:0% +and then you can also + + + align:start position:0% +and then you can also +show the cellular solids models on the + + align:start position:0% +show the cellular solids models on the + + + align:start position:0% +show the cellular solids models on the +same + + align:start position:0% + + + + align:start position:0% + +plot so overall it shows you how the + + align:start position:0% +plot so overall it shows you how the + + + align:start position:0% +plot so overall it shows you how the +hierarchical structure fits together um + + align:start position:0% +hierarchical structure fits together um + + + align:start position:0% +hierarchical structure fits together um +can be + + align:start position:0% + + + + align:start position:0% + +modeled + + align:start position:0% +modeled + + + align:start position:0% +modeled +okay now there's some more cute things + + align:start position:0% +okay now there's some more cute things + + + align:start position:0% +okay now there's some more cute things +we can see + + align:start position:0% + + + + align:start position:0% + +oh so another thing I wanted to talk + + align:start position:0% +oh so another thing I wanted to talk + + + align:start position:0% +oh so another thing I wanted to talk +about about is material selection + + align:start position:0% +about about is material selection + + + align:start position:0% +about about is material selection +because it turns out wood is very good + + align:start position:0% +because it turns out wood is very good + + + align:start position:0% +because it turns out wood is very good +compared to other materials in certain + + align:start position:0% +compared to other materials in certain + + + align:start position:0% +compared to other materials in certain +applications so we're going to look at + + align:start position:0% +applications so we're going to look at + + + align:start position:0% +applications so we're going to look at +say having a beam of a given stiffness + + align:start position:0% +say having a beam of a given stiffness + + + align:start position:0% +say having a beam of a given stiffness +and a given span and say it's just a + + align:start position:0% +and a given span and say it's just a + + + align:start position:0% +and a given span and say it's just a +rectangular or a square cross-section + + align:start position:0% +rectangular or a square cross-section + + + align:start position:0% +rectangular or a square cross-section +beam of edge length T and the question + + align:start position:0% +beam of edge length T and the question + + + align:start position:0% +beam of edge length T and the question +is what material would minimize the mass + + align:start position:0% +is what material would minimize the mass + + + align:start position:0% +is what material would minimize the mass +of the beam so say we have you know some + + align:start position:0% +of the beam so say we have you know some + + + align:start position:0% +of the beam so say we have you know some +span we have to have it's got to have + + align:start position:0% +span we have to have it's got to have + + + align:start position:0% +span we have to have it's got to have +some rectangular cross-section um some + + align:start position:0% +some rectangular cross-section um some + + + align:start position:0% +some rectangular cross-section um some +given stiffness and the question is + + align:start position:0% +given stiffness and the question is + + + align:start position:0% +given stiffness and the question is +what's the material that minimizes the + + align:start position:0% +what's the material that minimizes the + + + align:start position:0% +what's the material that minimizes the +mass so there's a little short + + align:start position:0% +mass so there's a little short + + + align:start position:0% +mass so there's a little short +calculation we can do to figure that out + + align:start position:0% +calculation we can do to figure that out + + + align:start position:0% +calculation we can do to figure that out +and then I've got another plot and you + + align:start position:0% +and then I've got another plot and you + + + align:start position:0% +and then I've got another plot and you +can compare different materials on this + + align:start position:0% +can compare different materials on this + + + align:start position:0% +can compare different materials on this +other plot and you'll see how how good + + align:start position:0% +other plot and you'll see how how good + + + align:start position:0% +other plot and you'll see how how good +wood is compared to other + + align:start position:0% + + + + align:start position:0% + +materials so for a beam of a given + + align:start position:0% + + + + align:start position:0% + +stiffness a given + + align:start position:0% +stiffness a given + + + align:start position:0% +stiffness a given +span and say it's a square cross-section + + align:start position:0% + + + + align:start position:0% + +then the question is what material + + align:start position:0% +then the question is what material + + + align:start position:0% +then the question is what material +minimizes the mass of the + + align:start position:0% + + + + align:start position:0% + +beam you guys okay yeah + + align:start position:0% + + + + align:start position:0% + +so the mass is just going to be the + + align:start position:0% +so the mass is just going to be the + + + align:start position:0% +so the mass is just going to be the +density * T ^2 * + + align:start position:0% +density * T ^2 * + + + align:start position:0% +density * T ^2 * +L and if it's a beam say it's got some + + align:start position:0% +L and if it's a beam say it's got some + + + align:start position:0% +L and if it's a beam say it's got some +Central load on it concentrated load the + + align:start position:0% +Central load on it concentrated load the + + + align:start position:0% +Central load on it concentrated load the +deflection is going to go as PL + + align:start position:0% +deflection is going to go as PL + + + align:start position:0% +deflection is going to go as PL +cubed divided by some constant and + + align:start position:0% +cubed divided by some constant and + + + align:start position:0% +cubed divided by some constant and +divided by the Young's modulus and the + + align:start position:0% +divided by the Young's modulus and the + + + align:start position:0% +divided by the Young's modulus and the +moment of inertia + + align:start position:0% +moment of inertia + + + align:start position:0% +moment of inertia +I so the stiffness if I just rearrange + + align:start position:0% +I so the stiffness if I just rearrange + + + align:start position:0% +I so the stiffness if I just rearrange +this the stiffness p over Delta + + align:start position:0% +this the stiffness p over Delta + + + align:start position:0% +this the stiffness p over Delta +that's going to go as u p over + + align:start position:0% +that's going to go as u p over + + + align:start position:0% +that's going to go as u p over +Delta CI and I is going to go as t to + + align:start position:0% +Delta CI and I is going to go as t to + + + align:start position:0% +Delta CI and I is going to go as t to +the + + align:start position:0% +the + + + align:start position:0% +the +4th over L cubed and then I can solve + + align:start position:0% +4th over L cubed and then I can solve + + + align:start position:0% +4th over L cubed and then I can solve +that for t^2 and I I want t^2 because + + align:start position:0% +that for t^2 and I I want t^2 because + + + align:start position:0% +that for t^2 and I I want t^2 because +I'm going to plug it back into the + + align:start position:0% +I'm going to plug it back into the + + + align:start position:0% +I'm going to plug it back into the +equation for the mass so if I solve this + + align:start position:0% +equation for the mass so if I solve this + + + align:start position:0% +equation for the mass so if I solve this +for + + align:start position:0% +for + + + align:start position:0% +for +t^2 I've got my stiffness p over Delta + + align:start position:0% +t^2 I've got my stiffness p over Delta + + + align:start position:0% +t^2 I've got my stiffness p over Delta +I've got L cubed divided by c + + align:start position:0% +I've got L cubed divided by c + + + align:start position:0% +I've got L cubed divided by c +e and then I take that whole thing the + + align:start position:0% +e and then I take that whole thing the + + + align:start position:0% +e and then I take that whole thing the +1/2 power like that and then I plug the + + align:start position:0% +1/2 power like that and then I plug the + + + align:start position:0% +1/2 power like that and then I plug the +t^2 back into the little equation for + + align:start position:0% +t^2 back into the little equation for + + + align:start position:0% +t^2 back into the little equation for +the + + align:start position:0% +the + + + align:start position:0% +the +mass so I've got + + align:start position:0% +mass so I've got + + + align:start position:0% +mass so I've got +density p over Delta * L cubed over c + + align:start position:0% +density p over Delta * L cubed over c + + + align:start position:0% +density p over Delta * L cubed over c +e and we take that whole thing to 1 half + + align:start position:0% +e and we take that whole thing to 1 half + + + align:start position:0% +e and we take that whole thing to 1 half +power we have another L and so to + + align:start position:0% +power we have another L and so to + + + align:start position:0% +power we have another L and so to +minimize the mass you want to look at + + align:start position:0% +minimize the mass you want to look at + + + align:start position:0% +minimize the mass you want to look at +the material properties and here the + + align:start position:0% +the material properties and here the + + + align:start position:0% +the material properties and here the +material properties of the density and + + align:start position:0% +material properties of the density and + + + align:start position:0% +material properties of the density and +the Young's modulus + + align:start position:0% +the Young's modulus + + + align:start position:0% +the Young's modulus +and to to minimize the mass you want to + + align:start position:0% +and to to minimize the mass you want to + + + align:start position:0% +and to to minimize the mass you want to +minimize row E to2 + + align:start position:0% + + + + align:start position:0% + +power or conversely you want to maximize + + align:start position:0% +power or conversely you want to maximize + + + align:start position:0% +power or conversely you want to maximize +e to the 1/2 over + + align:start position:0% + + + + align:start position:0% + +row okay so if you just had if you had a + + align:start position:0% +row okay so if you just had if you had a + + + align:start position:0% +row okay so if you just had if you had a +bar that you were just pulling on you + + align:start position:0% +bar that you were just pulling on you + + + align:start position:0% +bar that you were just pulling on you +would just want to maximize e over row + + align:start position:0% +would just want to maximize e over row + + + align:start position:0% +would just want to maximize e over row +but if it's a beam in bending it works + + align:start position:0% +but if it's a beam in bending it works + + + align:start position:0% +but if it's a beam in bending it works +out that you want to maximize e to the + + align:start position:0% +out that you want to maximize e to the + + + align:start position:0% +out that you want to maximize e to the +1/2 over row and if we look at the next + + align:start position:0% +1/2 over row and if we look at the next + + + align:start position:0% +1/2 over row and if we look at the next +slide this next slide then + + align:start position:0% +slide this next slide then + + + align:start position:0% +slide this next slide then +plots on a log log scale it plots the + + align:start position:0% +plots on a log log scale it plots the + + + align:start position:0% +plots on a log log scale it plots the +modulus on this axis and the density on + + align:start position:0% +modulus on this axis and the density on + + + align:start position:0% +modulus on this axis and the density on +that axis and here this plotted uh data + + align:start position:0% +that axis and here this plotted uh data + + + align:start position:0% +that axis and here this plotted uh data +for lots of different materials so + + align:start position:0% +for lots of different materials so + + + align:start position:0% +for lots of different materials so +there's engineering Alloys metals are up + + align:start position:0% +there's engineering Alloys metals are up + + + align:start position:0% +there's engineering Alloys metals are up +here engineering Ceramics are here + + align:start position:0% +here engineering Ceramics are here + + + align:start position:0% +here engineering Ceramics are here +Composites are here polymers are down + + align:start position:0% +Composites are here polymers are down + + + align:start position:0% +Composites are here polymers are down +here elastomer is way down here foamy + + align:start position:0% +here elastomer is way down here foamy + + + align:start position:0% +here elastomer is way down here foamy +things down here and this envelope here + + align:start position:0% +things down here and this envelope here + + + align:start position:0% +things down here and this envelope here +is woods and notice the log scale here + + align:start position:0% +is woods and notice the log scale here + + + align:start position:0% +is woods and notice the log scale here +the the lowest stiffness polymer Foams + + align:start position:0% +the the lowest stiffness polymer Foams + + + align:start position:0% +the the lowest stiffness polymer Foams +here are 01 gigap Pascal and diamond is + + align:start position:0% +here are 01 gigap Pascal and diamond is + + + align:start position:0% +here are 01 gigap Pascal and diamond is +up here at a th000 gigap pascal so + + align:start position:0% +up here at a th000 gigap pascal so + + + align:start position:0% +up here at a th000 gigap pascal so +there's like five orders of magnitude + + align:start position:0% +there's like five orders of magnitude + + + align:start position:0% +there's like five orders of magnitude +difference in the modulus + + align:start position:0% +difference in the modulus + + + align:start position:0% +difference in the modulus +here so then if you look at the bottom + + align:start position:0% +here so then if you look at the bottom + + + align:start position:0% +here so then if you look at the bottom +right corner here there's a bunch of + + align:start position:0% +right corner here there's a bunch of + + + align:start position:0% +right corner here there's a bunch of +dashed lines lines and this red one here + + align:start position:0% +dashed lines lines and this red one here + + + align:start position:0% +dashed lines lines and this red one here +is e to 1/2 over row so if it's log log + + align:start position:0% +is e to 1/2 over row so if it's log log + + + align:start position:0% +is e to 1/2 over row so if it's log log +plot e to 1/2 over row is going to show + + align:start position:0% +plot e to 1/2 over row is going to show + + + align:start position:0% +plot e to 1/2 over row is going to show +up as a straight line and every point on + + align:start position:0% +up as a straight line and every point on + + + align:start position:0% +up as a straight line and every point on +that line has the same value of e to the + + align:start position:0% +that line has the same value of e to the + + + align:start position:0% +that line has the same value of e to the +1/2 over + + align:start position:0% +1/2 over + + + align:start position:0% +1/2 over +row and the material that would be the + + align:start position:0% +row and the material that would be the + + + align:start position:0% +row and the material that would be the +best um for a beam of a given stiffness + + align:start position:0% +best um for a beam of a given stiffness + + + align:start position:0% +best um for a beam of a given stiffness +would be the one that has the biggest + + align:start position:0% +would be the one that has the biggest + + + align:start position:0% +would be the one that has the biggest +value of e to the 1/2 over row and if I + + align:start position:0% +value of e to the 1/2 over row and if I + + + align:start position:0% +value of e to the 1/2 over row and if I +move the line up to the top left here + + align:start position:0% +move the line up to the top left here + + + align:start position:0% +move the line up to the top left here +I'm increasing e I'm decreasing row it's + + align:start position:0% +I'm increasing e I'm decreasing row it's + + + align:start position:0% +I'm increasing e I'm decreasing row it's +got the biggest value of e to the 1/2 + + align:start position:0% +got the biggest value of e to the 1/2 + + + align:start position:0% +got the biggest value of e to the 1/2 +over row so the materials that are on + + align:start position:0% +over row so the materials that are on + + + align:start position:0% +over row so the materials that are on +this line here they all have the same + + align:start position:0% +this line here they all have the same + + + align:start position:0% +this line here they all have the same +value of e to the 1/2 over row and + + align:start position:0% +value of e to the 1/2 over row and + + + align:start position:0% +value of e to the 1/2 over row and +they've got the biggest value well + + align:start position:0% +they've got the biggest value well + + + align:start position:0% +they've got the biggest value well +virtually the biggest value uh so let's + + align:start position:0% +virtually the biggest value uh so let's + + + align:start position:0% +virtually the biggest value uh so let's +look at what those materials are there's + + align:start position:0% +look at what those materials are there's + + + align:start position:0% +look at what those materials are there's +there's things like engineering Ceramics + + align:start position:0% +there's things like engineering Ceramics + + + align:start position:0% +there's things like engineering Ceramics +like diamond that maybe are not the most + + align:start position:0% +like diamond that maybe are not the most + + + align:start position:0% +like diamond that maybe are not the most +convenient thing to make our beam out of + + align:start position:0% +convenient thing to make our beam out of + + + align:start position:0% +convenient thing to make our beam out of +and tend to be brittle and might break + + align:start position:0% +and tend to be brittle and might break + + + align:start position:0% +and tend to be brittle and might break +so they have some issues there's + + align:start position:0% +so they have some issues there's + + + align:start position:0% +so they have some issues there's +engineering Composites so things like uh + + align:start position:0% +engineering Composites so things like uh + + + align:start position:0% +engineering Composites so things like uh +carbon fiber reinforced Plastics and at + + align:start position:0% +carbon fiber reinforced Plastics and at + + + align:start position:0% +carbon fiber reinforced Plastics and at +this sort of tip of the Composites + + align:start position:0% +this sort of tip of the Composites + + + align:start position:0% +this sort of tip of the Composites +there'd be things like un uni + + align:start position:0% +there'd be things like un uni + + + align:start position:0% +there'd be things like un uni +unidirectional um fiber composites + + align:start position:0% +unidirectional um fiber composites + + + align:start position:0% +unidirectional um fiber composites +and then here's the woods down here so + + align:start position:0% +and then here's the woods down here so + + + align:start position:0% +and then here's the woods down here so +the woods have the same performance + + align:start position:0% +the woods have the same performance + + + align:start position:0% +the woods have the same performance +Index this is called the same value of e + + align:start position:0% +Index this is called the same value of e + + + align:start position:0% +Index this is called the same value of e +to the 1/2 over row as the best + + align:start position:0% +to the 1/2 over row as the best + + + align:start position:0% +to the 1/2 over row as the best +engineering Composites and so they have + + align:start position:0% +engineering Composites and so they have + + + align:start position:0% +engineering Composites and so they have +very good properties for their weight + + align:start position:0% +very good properties for their weight + + + align:start position:0% +very good properties for their weight +and one of the interesting things is if + + align:start position:0% +and one of the interesting things is if + + + align:start position:0% +and one of the interesting things is if +you look at this performance index of e + + align:start position:0% +you look at this performance index of e + + + align:start position:0% +you look at this performance index of e +to the 1/2 over + + align:start position:0% +to the 1/2 over + + + align:start position:0% +to the 1/2 over +row this is the performance index for + + align:start position:0% +row this is the performance index for + + + align:start position:0% +row this is the performance index for +the wood this is for the solid cell wall + + align:start position:0% +the wood this is for the solid cell wall + + + align:start position:0% +the wood this is for the solid cell wall +material that the woods made from so e + + align:start position:0% +material that the woods made from so e + + + align:start position:0% +material that the woods made from so e +to 1/2 uh of the solid over rope the + + align:start position:0% +to 1/2 uh of the solid over rope the + + + align:start position:0% +to 1/2 uh of the solid over rope the +solid and from the modeling of the wood + + align:start position:0% +solid and from the modeling of the wood + + + align:start position:0% +solid and from the modeling of the wood +just looking at the axial modulus this + + align:start position:0% +just looking at the axial modulus this + + + align:start position:0% +just looking at the axial modulus this +thing here is equal to that times row s + + align:start position:0% +thing here is equal to that times row s + + + align:start position:0% +thing here is equal to that times row s +over row so if you look at this this is + + align:start position:0% +over row so if you look at this this is + + + align:start position:0% +over row so if you look at this this is +the performance index for the wood this + + align:start position:0% +the performance index for the wood this + + + align:start position:0% +the performance index for the wood this +is the solid it's made from this number + + align:start position:0% +is the solid it's made from this number + + + align:start position:0% +is the solid it's made from this number +here is bigger than one right because + + align:start position:0% +here is bigger than one right because + + + align:start position:0% +here is bigger than one right because +the density of the solid is bigger than + + align:start position:0% +the density of the solid is bigger than + + + align:start position:0% +the density of the solid is bigger than +the density of the wood and so this is + + align:start position:0% +the density of the wood and so this is + + + align:start position:0% +the density of the wood and so this is +saying the wood is more efficient than + + align:start position:0% +saying the wood is more efficient than + + + align:start position:0% +saying the wood is more efficient than +the thing that it's made from than the + + align:start position:0% +the thing that it's made from than the + + + align:start position:0% +the thing that it's made from than the +solid that it's made from and so that's + + align:start position:0% +solid that it's made from and so that's + + + align:start position:0% +solid that it's made from and so that's +the the sort of plot for the stiffness + + align:start position:0% +the the sort of plot for the stiffness + + + align:start position:0% +the the sort of plot for the stiffness +and there's a similar plot for the + + align:start position:0% +and there's a similar plot for the + + + align:start position:0% +and there's a similar plot for the +strength that if you do this same little + + align:start position:0% +strength that if you do this same little + + + align:start position:0% +strength that if you do this same little +kind of calculation you find that the + + align:start position:0% +kind of calculation you find that the + + + align:start position:0% +kind of calculation you find that the +performance index for the strength is + + align:start position:0% +performance index for the strength is + + + align:start position:0% +performance index for the strength is +some failure strength raised to the 2/3 + + align:start position:0% +some failure strength raised to the 2/3 + + + align:start position:0% +some failure strength raised to the 2/3 +power over row and again here we're + + align:start position:0% +power over row and again here we're + + + align:start position:0% +power over row and again here we're +plotting strength versus density on a + + align:start position:0% +plotting strength versus density on a + + + align:start position:0% +plotting strength versus density on a +log log plot and this red line here is + + align:start position:0% +log log plot and this red line here is + + + align:start position:0% +log log plot and this red line here is +uh the strength of the 2/3 over row and + + align:start position:0% +uh the strength of the 2/3 over row and + + + align:start position:0% +uh the strength of the 2/3 over row and +again if we scoot over here so we have a + + align:start position:0% +again if we scoot over here so we have a + + + align:start position:0% +again if we scoot over here so we have a +parallel line every point on that line + + align:start position:0% +parallel line every point on that line + + + align:start position:0% +parallel line every point on that line +has the same value of the strength um to + + align:start position:0% +has the same value of the strength um to + + + align:start position:0% +has the same value of the strength um to +the 2/3 power over the density and these + + align:start position:0% +the 2/3 power over the density and these + + + align:start position:0% +the 2/3 power over the density and these +are the materials that have the highest + + align:start position:0% +are the materials that have the highest + + + align:start position:0% +are the materials that have the highest +values and again here's engineering + + align:start position:0% +values and again here's engineering + + + align:start position:0% +values and again here's engineering +Composites uh these are Ceramics but the + + align:start position:0% +Composites uh these are Ceramics but the + + + align:start position:0% +Composites uh these are Ceramics but the +Ceramics they have a high compressive + + align:start position:0% +Ceramics they have a high compressive + + + align:start position:0% +Ceramics they have a high compressive +strength but they tend to be brittle so + + align:start position:0% +strength but they tend to be brittle so + + + align:start position:0% +strength but they tend to be brittle so +it's not really a practical strength U + + align:start position:0% +it's not really a practical strength U + + + align:start position:0% +it's not really a practical strength U +these are metals in here and here's the + + align:start position:0% +these are metals in here and here's the + + + align:start position:0% +these are metals in here and here's the +woods down here so it's kind of + + align:start position:0% +woods down here so it's kind of + + + align:start position:0% +woods down here so it's kind of +interesting just to see that the wood + + align:start position:0% +interesting just to see that the wood + + + align:start position:0% +interesting just to see that the wood +has such a good property yes um so why + + align:start position:0% +has such a good property yes um so why + + + align:start position:0% +has such a good property yes um so why +so I like realized like why this is + + align:start position:0% +so I like realized like why this is + + + align:start position:0% +so I like realized like why this is +valuable setting it this setting up the + + align:start position:0% +valuable setting it this setting up the + + + align:start position:0% +valuable setting it this setting up the +problem this way but um if you're + + align:start position:0% +problem this way but um if you're + + + align:start position:0% +problem this way but um if you're +actually trying to design something why + + align:start position:0% +actually trying to design something why + + + align:start position:0% +actually trying to design something why +would you want to fix your cross-section + + align:start position:0% +would you want to fix your cross-section + + + align:start position:0% +would you want to fix your cross-section +oh but you could change your change your + + align:start position:0% +oh but you could change your change your + + + align:start position:0% +oh but you could change your change your +material true and change your + + align:start position:0% +material true and change your + + + align:start position:0% +material true and change your +crosssection so this is the this is the + + align:start position:0% +crosssection so this is the this is the + + + align:start position:0% +crosssection so this is the this is the +starter uh version of this problem and + + align:start position:0% +starter uh version of this problem and + + + align:start position:0% +starter uh version of this problem and +there's another part two of the problem + + align:start position:0% +there's another part two of the problem + + + align:start position:0% +there's another part two of the problem +is to change the shape and you could + + align:start position:0% +is to change the shape and you could + + + align:start position:0% +is to change the shape and you could +look at what shape's efficient there's + + align:start position:0% +look at what shape's efficient there's + + + align:start position:0% +look at what shape's efficient there's +something called a shape factor that + + align:start position:0% +something called a shape factor that + + + align:start position:0% +something called a shape factor that +gives you the efficient shapes so you + + align:start position:0% +gives you the efficient shapes so you + + + align:start position:0% +gives you the efficient shapes so you +could take the material and turn it into + + align:start position:0% +could take the material and turn it into + + + align:start position:0% +could take the material and turn it into +a different shape and have a more + + align:start position:0% +a different shape and have a more + + + align:start position:0% +a different shape and have a more +efficient thing because it was a + + align:start position:0% +efficient thing because it was a + + + align:start position:0% +efficient thing because it was a +different shape so there is a you can't + + align:start position:0% +different shape so there is a you can't + + + align:start position:0% +different shape so there is a you can't +count for if you did if you vared like + + align:start position:0% +count for if you did if you vared like + + + align:start position:0% +count for if you did if you vared like +let's say you made your cross-section + + align:start position:0% +let's say you made your cross-section + + + align:start position:0% +let's say you made your cross-section +smaller like even if it was still Square + + align:start position:0% +smaller like even if it was still Square + + + align:start position:0% +smaller like even if it was still Square +you would just still make it + + align:start position:0% +you would just still make it + + + align:start position:0% +you would just still make it +oh yeah I'm saying we've got a given + + align:start position:0% +oh yeah I'm saying we've got a given + + + align:start position:0% +oh yeah I'm saying we've got a given +stiffness so if we're given a certain + + align:start position:0% +stiffness so if we're given a certain + + + align:start position:0% +stiffness so if we're given a certain +stiffness and a certain span we would + + align:start position:0% +stiffness and a certain span we would + + + align:start position:0% +stiffness and a certain span we would +need a certain cross-section to get to + + align:start position:0% +need a certain cross-section to get to + + + align:start position:0% +need a certain cross-section to get to +that + + align:start position:0% +that + + + align:start position:0% +that +stiffness + + align:start position:0% +stiffness + + + align:start position:0% +stiffness +okay yeah are we happy yeah okay okay so + + align:start position:0% +okay yeah are we happy yeah okay okay so + + + align:start position:0% +okay yeah are we happy yeah okay okay so +that's uh one thing um let's see here so + + align:start position:0% +that's uh one thing um let's see here so + + + align:start position:0% +that's uh one thing um let's see here so +let me just write a few more notes about + + align:start position:0% +let me just write a few more notes about + + + align:start position:0% +let me just write a few more notes about +the material selection and then there's + + align:start position:0% +the material selection and then there's + + + align:start position:0% +the material selection and then there's +one more thing I wanted to show you + + align:start position:0% +one more thing I wanted to show you + + + align:start position:0% +one more thing I wanted to show you +about the + + align:start position:0% + + + + align:start position:0% + +woods C's just a constant so it's just + + align:start position:0% +woods C's just a constant so it's just + + + align:start position:0% +woods C's just a constant so it's just +some number so you know if you had a + + align:start position:0% +some number so you know if you had a + + + align:start position:0% +some number so you know if you had a +beam in three-point bending then C would + + align:start position:0% +beam in three-point bending then C would + + + align:start position:0% +beam in three-point bending then C would +be three if you had a beam that was + + align:start position:0% +be three if you had a beam that was + + + align:start position:0% +be three if you had a beam that was +simply supported with a central load C + + align:start position:0% +simply supported with a central load C + + + align:start position:0% +simply supported with a central load C +would be 48 C's just a + + align:start position:0% + + + + align:start position:0% + +number + + align:start position:0% +number + + + align:start position:0% +number +line choice is really just about + + align:start position:0% +line choice is really just about + + + align:start position:0% +line choice is really just about +cost um no it's not about cost there's + + align:start position:0% +cost um no it's not about cost there's + + + align:start position:0% +cost um no it's not about cost there's +nothing on cost here it it's all really + + align:start position:0% +nothing on cost here it it's all really + + + align:start position:0% +nothing on cost here it it's all really +about the properties what's the best + + align:start position:0% +about the properties what's the best + + + align:start position:0% +about the properties what's the best +combination of properties to minimize + + align:start position:0% +combination of properties to minimize + + + align:start position:0% +combination of properties to minimize +the mass and then which the which + + align:start position:0% +the mass and then which the which + + + align:start position:0% +the mass and then which the which +material has that combination of + + align:start position:0% +material has that combination of + + + align:start position:0% +material has that combination of +properties you can you can do charts + + align:start position:0% +properties you can you can do charts + + + align:start position:0% +properties you can you can do charts +like this that include cost um you can + + align:start position:0% +like this that include cost um you can + + + align:start position:0% +like this that include cost um you can +make these charts with whatever property + + align:start position:0% +make these charts with whatever property + + + align:start position:0% +make these charts with whatever property +you + + align:start position:0% + + + + align:start position:0% + +want I guess + + align:start position:0% +want I guess + + + align:start position:0% +want I guess +the I guess maybe there's a difference + + align:start position:0% +the I guess maybe there's a difference + + + align:start position:0% +the I guess maybe there's a difference +in two or so of + + align:start position:0% +in two or so of + + + align:start position:0% +in two or so of +strength uh between Pine and + + align:start position:0% +strength uh between Pine and + + + align:start position:0% +strength uh between Pine and +Balsa yeah maybe more than that I think + + align:start position:0% +Balsa yeah maybe more than that I think + + + align:start position:0% +Balsa yeah maybe more than that I think +I can't quite see where Pine's close to + + align:start position:0% +I can't quite see where Pine's close to + + + align:start position:0% +I can't quite see where Pine's close to +100 and B is I don't know 20 or + + align:start position:0% + + + + align:start position:0% + +somethinge yeah and it's not I mean the + + align:start position:0% +somethinge yeah and it's not I mean the + + + align:start position:0% +somethinge yeah and it's not I mean the +point of this isn't so much looking at + + align:start position:0% +point of this isn't so much looking at + + + align:start position:0% +point of this isn't so much looking at +the absolute value of the strength it's + + align:start position:0% +the absolute value of the strength it's + + + align:start position:0% +the absolute value of the strength it's +looking at the value of this performance + + align:start position:0% +looking at the value of this performance + + + align:start position:0% +looking at the value of this performance +index and uh what you want to do is + + align:start position:0% +index and uh what you want to do is + + + align:start position:0% +index and uh what you want to do is +maximize that index to get the material + + align:start position:0% +maximize that index to get the material + + + align:start position:0% +maximize that index to get the material +that's going to minimize the mass okay + + align:start position:0% +that's going to minimize the mass okay + + + align:start position:0% +that's going to minimize the mass okay +okay so let me just write a couple notes + + align:start position:0% +okay so let me just write a couple notes + + + align:start position:0% +okay so let me just write a couple notes +about this so we have these These are + + align:start position:0% +about this so we have these These are + + + align:start position:0% +about this so we have these These are +called material selection charts + + align:start position:0% + + + + align:start position:0% + +so you plot the log of one property + + align:start position:0% +so you plot the log of one property + + + align:start position:0% +so you plot the log of one property +versus the log of some other + + align:start position:0% + + + + align:start position:0% + +property and then we have a line of + + align:start position:0% +property and then we have a line of + + + align:start position:0% +property and then we have a line of +constant e to the 1/2 over + + align:start position:0% +constant e to the 1/2 over + + + align:start position:0% +constant e to the 1/2 over +row I'll just say it's shown in red + + align:start position:0% +row I'll just say it's shown in red + + + align:start position:0% +row I'll just say it's shown in red +because you're going to have the same + + align:start position:0% +because you're going to have the same + + + align:start position:0% +because you're going to have the same +plots + + align:start position:0% + + + + align:start position:0% + +and the materials with the largest + + align:start position:0% +and the materials with the largest + + + align:start position:0% +and the materials with the largest +values are on the upper + + align:start position:0% + + + + align:start position:0% + +left so the woods have similar values to + + align:start position:0% +left so the woods have similar values to + + + align:start position:0% +left so the woods have similar values to +any engineering + + align:start position:0% + + + + align:start position:0% + +composits and you can do a similar thing + + align:start position:0% +composits and you can do a similar thing + + + align:start position:0% +composits and you can do a similar thing +for + + align:start position:0% + + + + align:start position:0% + +strength okay so I have a few more + + align:start position:0% +strength okay so I have a few more + + + align:start position:0% +strength okay so I have a few more +minutes + + align:start position:0% + + + + align:start position:0% + +so I have a few more minuts and I want + + align:start position:0% +so I have a few more minuts and I want + + + align:start position:0% +so I have a few more minuts and I want +to talk about a couple of uses of woods + + align:start position:0% +to talk about a couple of uses of woods + + + align:start position:0% +to talk about a couple of uses of woods +um so one is an old ships so I don't + + align:start position:0% +um so one is an old ships so I don't + + + align:start position:0% +um so one is an old ships so I don't +know if you know Professor Leman has + + align:start position:0% +know if you know Professor Leman has + + + align:start position:0% +know if you know Professor Leman has +this course materials and The Human + + align:start position:0% +this course materials and The Human + + + align:start position:0% +this course materials and The Human +Experience and they talk about sort of + + align:start position:0% +Experience and they talk about sort of + + + align:start position:0% +Experience and they talk about sort of +ancient uses of materials and I did a + + align:start position:0% +ancient uses of materials and I did a + + + align:start position:0% +ancient uses of materials and I did a +section a module on on woods and the use + + align:start position:0% +section a module on on woods and the use + + + align:start position:0% +section a module on on woods and the use +of woods in Old Colonial ships like the + + align:start position:0% +of woods in Old Colonial ships like the + + + align:start position:0% +of woods in Old Colonial ships like the +Constitution that's in in Boston Harbor + + align:start position:0% +Constitution that's in in Boston Harbor + + + align:start position:0% +Constitution that's in in Boston Harbor +so this is kind of a schematic of a an + + align:start position:0% +so this is kind of a schematic of a an + + + align:start position:0% +so this is kind of a schematic of a an +old uh ship and the thing that was + + align:start position:0% +old uh ship and the thing that was + + + align:start position:0% +old uh ship and the thing that was +interesting and the thing that I talked + + align:start position:0% +interesting and the thing that I talked + + + align:start position:0% +interesting and the thing that I talked +about in this module was that people + + align:start position:0% +about in this module was that people + + + align:start position:0% +about in this module was that people +chose particular species for particular + + align:start position:0% +chose particular species for particular + + + align:start position:0% +chose particular species for particular +parts of the boat and they would choose + + align:start position:0% +parts of the boat and they would choose + + + align:start position:0% +parts of the boat and they would choose +a particular species depending on its + + align:start position:0% +a particular species depending on its + + + align:start position:0% +a particular species depending on its +properties and a lot of the hull was + + align:start position:0% +properties and a lot of the hull was + + + align:start position:0% +properties and a lot of the hull was +made of oak so Oaks are very dense wood + + align:start position:0% +made of oak so Oaks are very dense wood + + + align:start position:0% +made of oak so Oaks are very dense wood +uh but they would get something they + + align:start position:0% +uh but they would get something they + + + align:start position:0% +uh but they would get something they +called straight Oak and they would get + + align:start position:0% +called straight Oak and they would get + + + align:start position:0% +called straight Oak and they would get +something they called Compass Oak and + + align:start position:0% +something they called Compass Oak and + + + align:start position:0% +something they called Compass Oak and +you can see this little thing down here + + align:start position:0% +you can see this little thing down here + + + align:start position:0% +you can see this little thing down here +this little kind of schematic here this + + align:start position:0% +this little kind of schematic here this + + + align:start position:0% +this little kind of schematic here this +little sketch + + align:start position:0% +little sketch + + + align:start position:0% +little sketch +uh this is straight Oak just a straight + + align:start position:0% +uh this is straight Oak just a straight + + + align:start position:0% +uh this is straight Oak just a straight +trunk and this thing here would be the + + align:start position:0% +trunk and this thing here would be the + + + align:start position:0% +trunk and this thing here would be the +compass Oak and what they would do is + + align:start position:0% +compass Oak and what they would do is + + + align:start position:0% +compass Oak and what they would do is +they would use the Straight Oak for + + align:start position:0% +they would use the Straight Oak for + + + align:start position:0% +they would use the Straight Oak for +straight parts of the boat so you know + + align:start position:0% +straight parts of the boat so you know + + + align:start position:0% +straight parts of the boat so you know +something like this these pieces here + + align:start position:0% +something like this these pieces here + + + align:start position:0% +something like this these pieces here +and then they would actually look for + + align:start position:0% +and then they would actually look for + + + align:start position:0% +and then they would actually look for +trees that had the curve of the branches + + align:start position:0% +trees that had the curve of the branches + + + align:start position:0% +trees that had the curve of the branches +to match some part of the boat that they + + align:start position:0% +to match some part of the boat that they + + + align:start position:0% +to match some part of the boat that they +were looking for so for instance um if + + align:start position:0% +were looking for so for instance um if + + + align:start position:0% +were looking for so for instance um if +you have the hull out here and the deck + + align:start position:0% +you have the hull out here and the deck + + + align:start position:0% +you have the hull out here and the deck +here and they had their cannons here + + align:start position:0% +here and they had their cannons here + + + align:start position:0% +here and they had their cannons here +there's something called a knee which is + + align:start position:0% +there's something called a knee which is + + + align:start position:0% +there's something called a knee which is +sort of a bracing piece that goes + + align:start position:0% +sort of a bracing piece that goes + + + align:start position:0% +sort of a bracing piece that goes +between the deck and the hull and that + + align:start position:0% +between the deck and the hull and that + + + align:start position:0% +between the deck and the hull and that +bracing piece is curved and they would + + align:start position:0% +bracing piece is curved and they would + + + align:start position:0% +bracing piece is curved and they would +actually look for trees in which the + + align:start position:0% +actually look for trees in which the + + + align:start position:0% +actually look for trees in which the +branches curved at the same kind of + + align:start position:0% +branches curved at the same kind of + + + align:start position:0% +branches curved at the same kind of +curvature as they were looking for in + + align:start position:0% +curvature as they were looking for in + + + align:start position:0% +curvature as they were looking for in +that piece and then they would use it + + align:start position:0% +that piece and then they would use it + + + align:start position:0% +that piece and then they would use it +for that piece and the advantage of this + + align:start position:0% +for that piece and the advantage of this + + + align:start position:0% +for that piece and the advantage of this +is they basically had the grain running + + align:start position:0% +is they basically had the grain running + + + align:start position:0% +is they basically had the grain running +along the curve and so they got the best + + align:start position:0% +along the curve and so they got the best + + + align:start position:0% +along the curve and so they got the best +properties out of the wood by doing that + + align:start position:0% +properties out of the wood by doing that + + + align:start position:0% +properties out of the wood by doing that +so they had this straight Oak and + + align:start position:0% +so they had this straight Oak and + + + align:start position:0% +so they had this straight Oak and +Compass Oak and that was one uh cute + + align:start position:0% +Compass Oak and that was one uh cute + + + align:start position:0% +Compass Oak and that was one uh cute +thing and often they used White Oaks and + + align:start position:0% +thing and often they used White Oaks and + + + align:start position:0% +thing and often they used White Oaks and +I brought a piece of white oak in you + + align:start position:0% +I brought a piece of white oak in you + + + align:start position:0% +I brought a piece of white oak in you +can see how dense it is and the US Navy + + align:start position:0% +can see how dense it is and the US Navy + + + align:start position:0% +can see how dense it is and the US Navy +uh often use something called live o + + align:start position:0% +uh often use something called live o + + + align:start position:0% +uh often use something called live o +Live Oak grows in the South anybody from + + align:start position:0% +Live Oak grows in the South anybody from + + + align:start position:0% +Live Oak grows in the South anybody from +the south you see these big trees with + + align:start position:0% +the south you see these big trees with + + + align:start position:0% +the south you see these big trees with +huge sort of spreading branches those + + align:start position:0% +huge sort of spreading branches those + + + align:start position:0% +huge sort of spreading branches those +are the Live Oaks and apparently the US + + align:start position:0% +are the Live Oaks and apparently the US + + + align:start position:0% +are the Live Oaks and apparently the US +Navy I read somewhere still has a forest + + align:start position:0% +Navy I read somewhere still has a forest + + + align:start position:0% +Navy I read somewhere still has a forest +somewhere with Live Oak for doing things + + align:start position:0% +somewhere with Live Oak for doing things + + + align:start position:0% +somewhere with Live Oak for doing things +like repairing the Constitution so let + + align:start position:0% +like repairing the Constitution so let + + + align:start position:0% +like repairing the Constitution so let +me just pass those guys around so those + + align:start position:0% +me just pass those guys around so those + + + align:start position:0% +me just pass those guys around so those +are a couple of the Oaks they would use + + align:start position:0% +are a couple of the Oaks they would use + + + align:start position:0% +are a couple of the Oaks they would use +for the hull then they would use uh + + align:start position:0% +for the hull then they would use uh + + + align:start position:0% +for the hull then they would use uh +White Pine for the masts and the reason + + align:start position:0% +White Pine for the masts and the reason + + + align:start position:0% +White Pine for the masts and the reason +they use White Pine for the Mast is the + + align:start position:0% +they use White Pine for the Mast is the + + + align:start position:0% +they use White Pine for the Mast is the +white pine grows very very tall and very + + align:start position:0% +white pine grows very very tall and very + + + align:start position:0% +white pine grows very very tall and very +straight and white pine was actually + + align:start position:0% +straight and white pine was actually + + + align:start position:0% +straight and white pine was actually +like a strategic resource in the 1600s + + align:start position:0% +like a strategic resource in the 1600s + + + align:start position:0% +like a strategic resource in the 1600s +and 1700s so and it turns out that when + + align:start position:0% +and 1700s so and it turns out that when + + + align:start position:0% +and 1700s so and it turns out that when +the British royal Navy was um you know + + align:start position:0% +the British royal Navy was um you know + + + align:start position:0% +the British royal Navy was um you know +doing all that Colonial stuff in the 16 + + align:start position:0% +doing all that Colonial stuff in the 16 + + + align:start position:0% +doing all that Colonial stuff in the 16 +1700s Britain actually ran out of trees + + align:start position:0% +1700s Britain actually ran out of trees + + + align:start position:0% +1700s Britain actually ran out of trees +for masts for boats and they would + + align:start position:0% +for masts for boats and they would + + + align:start position:0% +for masts for boats and they would +actually import masts from New England + + align:start position:0% +actually import masts from New England + + + align:start position:0% +actually import masts from New England +and there were these people called + + align:start position:0% +and there were these people called + + + align:start position:0% +and there were these people called +surveyors who would go around and they + + align:start position:0% +surveyors who would go around and they + + + align:start position:0% +surveyors who would go around and they +would Mark certain trees that were + + align:start position:0% +would Mark certain trees that were + + + align:start position:0% +would Mark certain trees that were +supposed to be saved for these masts for + + align:start position:0% +supposed to be saved for these masts for + + + align:start position:0% +supposed to be saved for these masts for +the British royal Navy and the the thing + + align:start position:0% +the British royal Navy and the the thing + + + align:start position:0% +the British royal Navy and the the thing +was that the the size of the boat and + + align:start position:0% +was that the the size of the boat and + + + align:start position:0% +was that the the size of the boat and +how many cannons you could put on the + + align:start position:0% +how many cannons you could put on the + + + align:start position:0% +how many cannons you could put on the +boat depending on how big the Mast was + + align:start position:0% +boat depending on how big the Mast was + + + align:start position:0% +boat depending on how big the Mast was +so the size of the boat depended on this + + align:start position:0% +so the size of the boat depended on this + + + align:start position:0% +so the size of the boat depended on this +the mass because the Mast the Mast + + align:start position:0% +the mass because the Mast the Mast + + + align:start position:0% +the mass because the Mast the Mast +height depended on uh it controlled how + + align:start position:0% +height depended on uh it controlled how + + + align:start position:0% +height depended on uh it controlled how +much sail area you could get so the + + align:start position:0% +much sail area you could get so the + + + align:start position:0% +much sail area you could get so the +taller the mass the more sail the more + + align:start position:0% +taller the mass the more sail the more + + + align:start position:0% +taller the mass the more sail the more +sail the bigger the ship bigger the ship + + align:start position:0% +sail the bigger the ship bigger the ship + + + align:start position:0% +sail the bigger the ship bigger the ship +the more cannons and so having these + + align:start position:0% +the more cannons and so having these + + + align:start position:0% +the more cannons and so having these +tall uh eastern white pines was a sort + + align:start position:0% +tall uh eastern white pines was a sort + + + align:start position:0% +tall uh eastern white pines was a sort +of a strategic resource and I have a + + align:start position:0% +of a strategic resource and I have a + + + align:start position:0% +of a strategic resource and I have a +piece of white pine unfortunately my dog + + align:start position:0% +piece of white pine unfortunately my dog + + + align:start position:0% +piece of white pine unfortunately my dog +got to this one so there's so there's + + align:start position:0% +got to this one so there's so there's + + + align:start position:0% +got to this one so there's so there's +some and be careful it's a bit splintery + + align:start position:0% +some and be careful it's a bit splintery + + + align:start position:0% +some and be careful it's a bit splintery +but you can see it's a lighter kind of + + align:start position:0% +but you can see it's a lighter kind of + + + align:start position:0% +but you can see it's a lighter kind of +wood and if you go around New England uh + + align:start position:0% +wood and if you go around New England uh + + + align:start position:0% +wood and if you go around New England uh +if you go to the Arboretum you can see + + align:start position:0% +if you go to the Arboretum you can see + + + align:start position:0% +if you go to the Arboretum you can see +White Oak and you can see eastern white + + align:start position:0% +White Oak and you can see eastern white + + + align:start position:0% +White Oak and you can see eastern white +pine the other wood they used is lignum + + align:start position:0% +pine the other wood they used is lignum + + + align:start position:0% +pine the other wood they used is lignum +V that first dense one that I passed + + align:start position:0% +V that first dense one that I passed + + + align:start position:0% +V that first dense one that I passed +around and if you notice that lignum V + + align:start position:0% +around and if you notice that lignum V + + + align:start position:0% +around and if you notice that lignum V +it has kind of a waxy feel to it and + + align:start position:0% +it has kind of a waxy feel to it and + + + align:start position:0% +it has kind of a waxy feel to it and +they Ed that in the block and tackle so + + align:start position:0% +they Ed that in the block and tackle so + + + align:start position:0% +they Ed that in the block and tackle so +like pulley and stuff like that and it + + align:start position:0% +like pulley and stuff like that and it + + + align:start position:0% +like pulley and stuff like that and it +was thought to be self-lubricating + + align:start position:0% +was thought to be self-lubricating + + + align:start position:0% +was thought to be self-lubricating +because of that kind of waxy layer on it + + align:start position:0% +because of that kind of waxy layer on it + + + align:start position:0% +because of that kind of waxy layer on it +and because it's very dense if you think + + align:start position:0% +and because it's very dense if you think + + + align:start position:0% +and because it's very dense if you think +of like a block and tackle and you've + + align:start position:0% +of like a block and tackle and you've + + + align:start position:0% +of like a block and tackle and you've +got like a rope going over a pulley + + align:start position:0% +got like a rope going over a pulley + + + align:start position:0% +got like a rope going over a pulley +you've got a pressure from you know + + align:start position:0% +you've got a pressure from you know + + + align:start position:0% +you've got a pressure from you know +everything sort of fitting together + + align:start position:0% +everything sort of fitting together + + + align:start position:0% +everything sort of fitting together +and the bits bearing against each other + + align:start position:0% +and the bits bearing against each other + + + align:start position:0% +and the bits bearing against each other +and the fact that it was very dense made + + align:start position:0% +and the fact that it was very dense made + + + align:start position:0% +and the fact that it was very dense made +it very good for the block and tackle + + align:start position:0% +it very good for the block and tackle + + + align:start position:0% +it very good for the block and tackle +and so they used the lignum V for that + + align:start position:0% +and so they used the lignum V for that + + + align:start position:0% +and so they used the lignum V for that +and there's one other cute story about + + align:start position:0% +and there's one other cute story about + + + align:start position:0% +and there's one other cute story about +lignum vitai um I don't know if any of + + align:start position:0% +lignum vitai um I don't know if any of + + + align:start position:0% +lignum vitai um I don't know if any of +you have ever read Davis sobel's book + + align:start position:0% +you have ever read Davis sobel's book + + + align:start position:0% +you have ever read Davis sobel's book +called longitude anybody read that I'm a + + align:start position:0% +called longitude anybody read that I'm a + + + align:start position:0% +called longitude anybody read that I'm a +sucker for those history of science + + align:start position:0% +sucker for those history of science + + + align:start position:0% +sucker for those history of science +books so her book longitude is about the + + align:start position:0% +books so her book longitude is about the + + + align:start position:0% +books so her book longitude is about the +development of an instrument to measure + + align:start position:0% +development of an instrument to measure + + + align:start position:0% +development of an instrument to measure +longitude they used to be able to + + align:start position:0% +longitude they used to be able to + + + align:start position:0% +longitude they used to be able to +navigate originally they could get the + + align:start position:0% +navigate originally they could get the + + + align:start position:0% +navigate originally they could get the +latitude from the stars but they were + + align:start position:0% +latitude from the stars but they were + + + align:start position:0% +latitude from the stars but they were +really bad at getting the LA itude and + + align:start position:0% +really bad at getting the LA itude and + + + align:start position:0% +really bad at getting the LA itude and +so boats would go off and they wouldn't + + align:start position:0% +so boats would go off and they wouldn't + + + align:start position:0% +so boats would go off and they wouldn't +really be able to figure out where they + + align:start position:0% +really be able to figure out where they + + + align:start position:0% +really be able to figure out where they +were until they had a method to measure + + align:start position:0% +were until they had a method to measure + + + align:start position:0% +were until they had a method to measure +longitude and there was some British I + + align:start position:0% +longitude and there was some British I + + + align:start position:0% +longitude and there was some British I +don't know Board of something or another + + align:start position:0% +don't know Board of something or another + + + align:start position:0% +don't know Board of something or another +they they put forward a prize for + + align:start position:0% +they they put forward a prize for + + + align:start position:0% +they they put forward a prize for +somebody who could produce a way of + + align:start position:0% +somebody who could produce a way of + + + align:start position:0% +somebody who could produce a way of +measuring longitude accurately and there + + align:start position:0% +measuring longitude accurately and there + + + align:start position:0% +measuring longitude accurately and there +was a guy called John Harrison and he + + align:start position:0% +was a guy called John Harrison and he + + + align:start position:0% +was a guy called John Harrison and he +built a clock he built a very accurate + + align:start position:0% +built a clock he built a very accurate + + + align:start position:0% +built a clock he built a very accurate +chronometer and if you knew you know + + align:start position:0% +chronometer and if you knew you know + + + align:start position:0% +chronometer and if you knew you know +when Sunrise was and sunset was and you + + align:start position:0% +when Sunrise was and sunset was and you + + + align:start position:0% +when Sunrise was and sunset was and you +knew the time where you left you could + + align:start position:0% +knew the time where you left you could + + + align:start position:0% +knew the time where you left you could +figure out where you it's kind of like + + align:start position:0% +figure out where you it's kind of like + + + align:start position:0% +figure out where you it's kind of like +time zones you could figure out where + + align:start position:0% +time zones you could figure out where + + + align:start position:0% +time zones you could figure out where +you are today and he built a chronometer + + align:start position:0% +you are today and he built a chronometer + + + align:start position:0% +you are today and he built a chronometer +and one version of his chronometer used + + align:start position:0% +and one version of his chronometer used + + + align:start position:0% +and one version of his chronometer used +the lignum V for the same reason because + + align:start position:0% +the lignum V for the same reason because + + + align:start position:0% +the lignum V for the same reason because +it was very dense and it was very stable + + align:start position:0% +it was very dense and it was very stable + + + align:start position:0% +it was very dense and it was very stable +um and the clock that he eventually won + + align:start position:0% +um and the clock that he eventually won + + + align:start position:0% +um and the clock that he eventually won +the prize with was in the 1700 + + align:start position:0% +the prize with was in the 1700 + + + align:start position:0% +the prize with was in the 1700 +1759 I think he they went on some trip + + align:start position:0% +1759 I think he they went on some trip + + + align:start position:0% +1759 I think he they went on some trip +with it it was 81 days at Sea and it + + align:start position:0% +with it it was 81 days at Sea and it + + + align:start position:0% +with it it was 81 days at Sea and it +lost 5 Seconds over 81 days so that's + + align:start position:0% +lost 5 Seconds over 81 days so that's + + + align:start position:0% +lost 5 Seconds over 81 days so that's +pretty impressive for you know 250 years + + align:start position:0% +pretty impressive for you know 250 years + + + align:start position:0% +pretty impressive for you know 250 years +ago so that was the lignum v in the + + align:start position:0% +ago so that was the lignum v in the + + + align:start position:0% +ago so that was the lignum v in the +clock and I have one more picture and + + align:start position:0% +clock and I have one more picture and + + + align:start position:0% +clock and I have one more picture and +then I can finish up the thing on wood + + align:start position:0% +then I can finish up the thing on wood + + + align:start position:0% +then I can finish up the thing on wood +and we'll start the cork next time + + align:start position:0% +and we'll start the cork next time + + + align:start position:0% +and we'll start the cork next time +so this is another example of using wood + + align:start position:0% +so this is another example of using wood + + + align:start position:0% +so this is another example of using wood +and this is sort of a more modern use so + + align:start position:0% +and this is sort of a more modern use so + + + align:start position:0% +and this is sort of a more modern use so +this bridge here is made with a glue + + align:start position:0% +this bridge here is made with a glue + + + align:start position:0% +this bridge here is made with a glue +laminated wood so this big beam here big + + align:start position:0% +laminated wood so this big beam here big + + + align:start position:0% +laminated wood so this big beam here big +arch is U made up of sections of wood + + align:start position:0% +arch is U made up of sections of wood + + + align:start position:0% +arch is U made up of sections of wood +which are uh glued together and you can + + align:start position:0% +which are uh glued together and you can + + + align:start position:0% +which are uh glued together and you can +glue the sections in a curved shape if + + align:start position:0% +glue the sections in a curved shape if + + + align:start position:0% +glue the sections in a curved shape if +you want and sort of have molds to do + + align:start position:0% +you want and sort of have molds to do + + + align:start position:0% +you want and sort of have molds to do +that and when they make this glue + + align:start position:0% +that and when they make this glue + + + align:start position:0% +that and when they make this glue +laminated wood they cut the defects out + + align:start position:0% +laminated wood they cut the defects out + + + align:start position:0% +laminated wood they cut the defects out +so they cut knots out and they you know + + align:start position:0% +so they cut knots out and they you know + + + align:start position:0% +so they cut knots out and they you know +they control the the pieces of each + + align:start position:0% +they control the the pieces of each + + + align:start position:0% +they control the the pieces of each +laminate that they use uh to get the + + align:start position:0% +laminate that they use uh to get the + + + align:start position:0% +laminate that they use uh to get the +best quality + + align:start position:0% +best quality + + + align:start position:0% +best quality +and the glue laminated wood actually has + + align:start position:0% +and the glue laminated wood actually has + + + align:start position:0% +and the glue laminated wood actually has +better properties than just you know + + align:start position:0% +better properties than just you know + + + align:start position:0% +better properties than just you know +2x4s or whatever you would cut down you + + align:start position:0% +2x4s or whatever you would cut down you + + + align:start position:0% +2x4s or whatever you would cut down you +know Lumber that you would cut from a + + align:start position:0% +know Lumber that you would cut from a + + + align:start position:0% +know Lumber that you would cut from a +tree so glue laminated wood is kind of a + + align:start position:0% +tree so glue laminated wood is kind of a + + + align:start position:0% +tree so glue laminated wood is kind of a +nice uh kind of uh wood structure that's + + align:start position:0% +nice uh kind of uh wood structure that's + + + align:start position:0% +nice uh kind of uh wood structure that's +used now and you see it all the time in + + align:start position:0% +used now and you see it all the time in + + + align:start position:0% +used now and you see it all the time in +things like um ice rink Arenas like + + align:start position:0% +things like um ice rink Arenas like + + + align:start position:0% +things like um ice rink Arenas like +large span it's and it's kind of + + align:start position:0% +large span it's and it's kind of + + + align:start position:0% +large span it's and it's kind of +beautiful you can see the wood grain and + + align:start position:0% +beautiful you can see the wood grain and + + + align:start position:0% +beautiful you can see the wood grain and +the curve in the wood grain when they + + align:start position:0% +the curve in the wood grain when they + + + align:start position:0% +the curve in the wood grain when they +make these things so that's the wood + + align:start position:0% +make these things so that's the wood + + + align:start position:0% +make these things so that's the wood +lecture I'm going to stop there so next + + align:start position:0% +lecture I'm going to stop there so next + + + align:start position:0% +lecture I'm going to stop there so next +time I'll talk about cork I just have a + + align:start position:0% +time I'll talk about cork I just have a + + + align:start position:0% +time I'll talk about cork I just have a +little bit about Cork and then uh we'll + + align:start position:0% +little bit about Cork and then uh we'll + + + align:start position:0% +little bit about Cork and then uh we'll +start talking about foams okay \ No newline at end of file diff --git a/jwJrF6kBuJ4.txt b/jwJrF6kBuJ4.txt new file mode 100644 index 0000000000000000000000000000000000000000..dd996d2d8a927c7a0a0934c3ec286854463386be --- /dev/null +++ b/jwJrF6kBuJ4.txt @@ -0,0 +1,4979 @@ +align:start position:0% + +instead of trying to convince the other + + align:start position:0% +instead of trying to convince the other + + + align:start position:0% +instead of trying to convince the other +person or persuade the other person + + align:start position:0% +person or persuade the other person + + + align:start position:0% +person or persuade the other person +listen help them empty their heart and + + align:start position:0% +listen help them empty their heart and + + + align:start position:0% +listen help them empty their heart and +express why they're frustrated with a + + align:start position:0% +express why they're frustrated with a + + + align:start position:0% +express why they're frustrated with a +situation and then they'll be more + + align:start position:0% +situation and then they'll be more + + + align:start position:0% +situation and then they'll be more +likely to listen to your own experiences + + align:start position:0% +likely to listen to your own experiences + + + align:start position:0% +likely to listen to your own experiences +and more receptive to why you think + + align:start position:0% +and more receptive to why you think + + + align:start position:0% +and more receptive to why you think +climate change + + align:start position:0% +climate change + + + align:start position:0% +climate change +matters and is relevant today on shock + + align:start position:0% +matters and is relevant today on shock + + + align:start position:0% +matters and is relevant today on shock +radio + + align:start position:0% +radio + + + align:start position:0% +radio +we're exploring climate action and how + + align:start position:0% +we're exploring climate action and how + + + align:start position:0% +we're exploring climate action and how +one nonprofit is providing a framework + + align:start position:0% +one nonprofit is providing a framework + + + align:start position:0% +one nonprofit is providing a framework +for young people + + align:start position:0% +for young people + + + align:start position:0% +for young people +to help affect change the thing about + + align:start position:0% +to help affect change the thing about + + + align:start position:0% +to help affect change the thing about +teaching young people + + align:start position:0% +teaching young people + + + align:start position:0% +teaching young people +in particular is that young people are + + align:start position:0% +in particular is that young people are + + + align:start position:0% +in particular is that young people are +open-minded + + align:start position:0% +open-minded + + + align:start position:0% +open-minded +to new material but they're mature + + align:start position:0% +to new material but they're mature + + + align:start position:0% +to new material but they're mature +enough to understand fairly complex + + align:start position:0% +enough to understand fairly complex + + + align:start position:0% +enough to understand fairly complex +concepts + + align:start position:0% +concepts + + + align:start position:0% +concepts +ultimately we hope that ambassadors will + + align:start position:0% +ultimately we hope that ambassadors will + + + align:start position:0% +ultimately we hope that ambassadors will +teach students + + align:start position:0% +teach students + + + align:start position:0% +teach students +students will teach families and + + align:start position:0% +students will teach families and + + + align:start position:0% +students will teach families and +families will demand action + + align:start position:0% + + + + align:start position:0% + +i'm your host sarah hansen with us today + + align:start position:0% +i'm your host sarah hansen with us today + + + align:start position:0% +i'm your host sarah hansen with us today +is brandon lachinsky + + align:start position:0% +is brandon lachinsky + + + align:start position:0% +is brandon lachinsky +a graduate student in the technology and + + align:start position:0% +a graduate student in the technology and + + + align:start position:0% +a graduate student in the technology and +policy masters program + + align:start position:0% +policy masters program + + + align:start position:0% +policy masters program +and the aeronautics and astronautics + + align:start position:0% +and the aeronautics and astronautics + + + align:start position:0% +and the aeronautics and astronautics +masters program at mit + + align:start position:0% +masters program at mit + + + align:start position:0% +masters program at mit +brandon's also working with a non-profit + + align:start position:0% +brandon's also working with a non-profit + + + align:start position:0% +brandon's also working with a non-profit +called earth dna + + align:start position:0% +called earth dna + + + align:start position:0% +called earth dna +if this organization sounds familiar to + + align:start position:0% +if this organization sounds familiar to + + + align:start position:0% +if this organization sounds familiar to +you it's because our last guest + + align:start position:0% +you it's because our last guest + + + align:start position:0% +you it's because our last guest +professor of astronautics deva newman + + align:start position:0% +professor of astronautics deva newman + + + align:start position:0% +professor of astronautics deva newman +co-founded earth dna it's a global + + align:start position:0% +co-founded earth dna it's a global + + + align:start position:0% +co-founded earth dna it's a global +platform for climate advocacy + + align:start position:0% +platform for climate advocacy + + + align:start position:0% +platform for climate advocacy +and action our guest today + + align:start position:0% +and action our guest today + + + align:start position:0% +and action our guest today +brandon helps create a program called + + align:start position:0% +brandon helps create a program called + + + align:start position:0% +brandon helps create a program called +earth dna + + align:start position:0% +earth dna + + + align:start position:0% +earth dna +ambassadors which provides young people + + align:start position:0% +ambassadors which provides young people + + + align:start position:0% +ambassadors which provides young people +with climate leadership + + align:start position:0% +with climate leadership + + + align:start position:0% +with climate leadership +training in addition to learning about + + align:start position:0% +training in addition to learning about + + + align:start position:0% +training in addition to learning about +the science behind climate change + + align:start position:0% +the science behind climate change + + + align:start position:0% +the science behind climate change +ambassadors also develop skills focused + + align:start position:0% +ambassadors also develop skills focused + + + align:start position:0% +ambassadors also develop skills focused +on communication + + align:start position:0% +on communication + + + align:start position:0% +on communication +negotiation and storytelling + + align:start position:0% +negotiation and storytelling + + + align:start position:0% +negotiation and storytelling +we envision a community of climate + + align:start position:0% +we envision a community of climate + + + align:start position:0% +we envision a community of climate +leaders + + align:start position:0% +leaders + + + align:start position:0% +leaders +who engage their own communities on + + align:start position:0% +who engage their own communities on + + + align:start position:0% +who engage their own communities on +their campuses + + align:start position:0% +their campuses + + + align:start position:0% +their campuses +at their schools on climate change + + align:start position:0% +at their schools on climate change + + + align:start position:0% +at their schools on climate change +current ambassadors + + align:start position:0% +current ambassadors + + + align:start position:0% +current ambassadors +come from different backgrounds whether + + align:start position:0% +come from different backgrounds whether + + + align:start position:0% +come from different backgrounds whether +phd students in immunology + + align:start position:0% +phd students in immunology + + + align:start position:0% +phd students in immunology +or undergraduate students in business + + align:start position:0% +or undergraduate students in business + + + align:start position:0% +or undergraduate students in business +some of them have teaching experience + + align:start position:0% +some of them have teaching experience + + + align:start position:0% +some of them have teaching experience +but not all of them + + align:start position:0% +but not all of them + + + align:start position:0% +but not all of them +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +one of the tools that earth dna equips + + align:start position:0% +one of the tools that earth dna equips + + + align:start position:0% +one of the tools that earth dna equips +their ambassadors with + + align:start position:0% +their ambassadors with + + + align:start position:0% +their ambassadors with +is called climate 101 + + align:start position:0% +is called climate 101 + + + align:start position:0% +is called climate 101 +available on mit open courseware and + + align:start position:0% +available on mit open courseware and + + + align:start position:0% +available on mit open courseware and +earthdna.org + + align:start position:0% +earthdna.org + + + align:start position:0% +earthdna.org +it's an interactive workshop that was + + align:start position:0% +it's an interactive workshop that was + + + align:start position:0% +it's an interactive workshop that was +designed to engage communities around + + align:start position:0% +designed to engage communities around + + + align:start position:0% +designed to engage communities around +climate change + + align:start position:0% +climate change + + + align:start position:0% +climate change +and motivate people to act but changing + + align:start position:0% +and motivate people to act but changing + + + align:start position:0% +and motivate people to act but changing +human behavior can be difficult + + align:start position:0% +human behavior can be difficult + + + align:start position:0% +human behavior can be difficult +so climate 101 starts with something a + + align:start position:0% +so climate 101 starts with something a + + + align:start position:0% +so climate 101 starts with something a +bit more approachable + + align:start position:0% +bit more approachable + + + align:start position:0% +bit more approachable +the power of conversation well i think + + align:start position:0% +the power of conversation well i think + + + align:start position:0% +the power of conversation well i think +talking about it is really important + + align:start position:0% +talking about it is really important + + + align:start position:0% +talking about it is really important +because i think that + + align:start position:0% +because i think that + + + align:start position:0% +because i think that +climate change has the stigma about it + + align:start position:0% +climate change has the stigma about it + + + align:start position:0% +climate change has the stigma about it +where if you + + align:start position:0% +where if you + + + align:start position:0% +where if you +even bring it up you're viewed as you + + align:start position:0% +even bring it up you're viewed as you + + + align:start position:0% +even bring it up you're viewed as you +know + + align:start position:0% +know + + + align:start position:0% +know +a hippie environmentalist and alarmists + + align:start position:0% +a hippie environmentalist and alarmists + + + align:start position:0% +a hippie environmentalist and alarmists +and all these things + + align:start position:0% +and all these things + + + align:start position:0% +and all these things +and so even by having conversations + + align:start position:0% +and so even by having conversations + + + align:start position:0% +and so even by having conversations +about it and making it normal to have + + align:start position:0% +about it and making it normal to have + + + align:start position:0% +about it and making it normal to have +conversations + + align:start position:0% +conversations + + + align:start position:0% +conversations +about climate change you empower others + + align:start position:0% +about climate change you empower others + + + align:start position:0% +about climate change you empower others +to do that as well and + + align:start position:0% +to do that as well and + + + align:start position:0% +to do that as well and +that's huge because for a lot of people + + align:start position:0% +that's huge because for a lot of people + + + align:start position:0% +that's huge because for a lot of people +they just don't hear about climate + + align:start position:0% +they just don't hear about climate + + + align:start position:0% +they just don't hear about climate +change that often + + align:start position:0% +change that often + + + align:start position:0% +change that often +or if they hear about it it's not + + align:start position:0% +or if they hear about it it's not + + + align:start position:0% +or if they hear about it it's not +necessarily the best information + + align:start position:0% +necessarily the best information + + + align:start position:0% +necessarily the best information +and so if we can have people talking + + align:start position:0% +and so if we can have people talking + + + align:start position:0% +and so if we can have people talking +about climate change in a way that's + + align:start position:0% +about climate change in a way that's + + + align:start position:0% +about climate change in a way that's +personal and meaningful + + align:start position:0% +personal and meaningful + + + align:start position:0% +personal and meaningful +to their family members who might be + + align:start position:0% +to their family members who might be + + + align:start position:0% +to their family members who might be +climate skeptics + + align:start position:0% +climate skeptics + + + align:start position:0% +climate skeptics +that's one of the best ways to create + + align:start position:0% +that's one of the best ways to create + + + align:start position:0% +that's one of the best ways to create +the attitude + + align:start position:0% +the attitude + + + align:start position:0% +the attitude +and behavioral change that's necessary + + align:start position:0% +and behavioral change that's necessary + + + align:start position:0% +and behavioral change that's necessary +to actually overcome + + align:start position:0% +to actually overcome + + + align:start position:0% +to actually overcome +the problem of climate change in + + align:start position:0% +the problem of climate change in + + + align:start position:0% +the problem of climate change in +addition to normalizing discussions on + + align:start position:0% +addition to normalizing discussions on + + + align:start position:0% +addition to normalizing discussions on +climate change + + align:start position:0% +climate change + + + align:start position:0% +climate change +the climate 101 presentation is designed + + align:start position:0% +the climate 101 presentation is designed + + + align:start position:0% +the climate 101 presentation is designed +to improve + + align:start position:0% +to improve + + + align:start position:0% +to improve +climate literacy that means empowering + + align:start position:0% +climate literacy that means empowering + + + align:start position:0% +climate literacy that means empowering +people to think critically about climate + + align:start position:0% +people to think critically about climate + + + align:start position:0% +people to think critically about climate +change data + + align:start position:0% +change data + + + align:start position:0% +change data +and research and even targeted marketing + + align:start position:0% +and research and even targeted marketing + + + align:start position:0% +and research and even targeted marketing +campaigns + + align:start position:0% +campaigns + + + align:start position:0% +campaigns +one of the things that we actually talk + + align:start position:0% +one of the things that we actually talk + + + align:start position:0% +one of the things that we actually talk +about in the climate 101 workshop + + align:start position:0% +about in the climate 101 workshop + + + align:start position:0% +about in the climate 101 workshop +is the effect of different + + align:start position:0% +is the effect of different + + + align:start position:0% +is the effect of different +information campaigns by fossil fuel + + align:start position:0% +information campaigns by fossil fuel + + + align:start position:0% +information campaigns by fossil fuel +companies + + align:start position:0% +companies + + + align:start position:0% +companies +who have a very clear interest in + + align:start position:0% +who have a very clear interest in + + + align:start position:0% +who have a very clear interest in +preventing any kind of climate action + + align:start position:0% +preventing any kind of climate action + + + align:start position:0% +preventing any kind of climate action +and in promoting misinformation among + + align:start position:0% +and in promoting misinformation among + + + align:start position:0% +and in promoting misinformation among +the public promoting doubt among the + + align:start position:0% +the public promoting doubt among the + + + align:start position:0% +the public promoting doubt among the +public + + align:start position:0% +public + + + align:start position:0% +public +about whether climate change happens + + align:start position:0% +about whether climate change happens + + + align:start position:0% +about whether climate change happens +it's really important for me + + align:start position:0% +it's really important for me + + + align:start position:0% +it's really important for me +that people are able to sift through all + + align:start position:0% +that people are able to sift through all + + + align:start position:0% +that people are able to sift through all +that competing information + + align:start position:0% +that competing information + + + align:start position:0% +that competing information +in order to decide for themselves + + align:start position:0% +in order to decide for themselves + + + align:start position:0% +in order to decide for themselves +whether climate change is real whether + + align:start position:0% +whether climate change is real whether + + + align:start position:0% +whether climate change is real whether +it matters + + align:start position:0% +it matters + + + align:start position:0% +it matters +to them and whether they should do + + align:start position:0% +to them and whether they should do + + + align:start position:0% +to them and whether they should do +something about it + + align:start position:0% +something about it + + + align:start position:0% +something about it +now i think the answer to all three of + + align:start position:0% +now i think the answer to all three of + + + align:start position:0% +now i think the answer to all three of +those questions is yes + + align:start position:0% +those questions is yes + + + align:start position:0% +those questions is yes +but i want to help people process this + + align:start position:0% +but i want to help people process this + + + align:start position:0% +but i want to help people process this +deluge of information by themselves and + + align:start position:0% +deluge of information by themselves and + + + align:start position:0% +deluge of information by themselves and +be aware + + align:start position:0% +be aware + + + align:start position:0% +be aware +that there are people that are + + align:start position:0% +that there are people that are + + + align:start position:0% +that there are people that are +intentionally trying to misinform them + + align:start position:0% +intentionally trying to misinform them + + + align:start position:0% +intentionally trying to misinform them +climate literacy is critical to efforts + + align:start position:0% +climate literacy is critical to efforts + + + align:start position:0% +climate literacy is critical to efforts +for creating a grassroots movement of + + align:start position:0% +for creating a grassroots movement of + + + align:start position:0% +for creating a grassroots movement of +climate change + + align:start position:0% +climate change + + + align:start position:0% +climate change +action brandon sees the earth dna + + align:start position:0% +action brandon sees the earth dna + + + align:start position:0% +action brandon sees the earth dna +ambassadors + + align:start position:0% +ambassadors + + + align:start position:0% +ambassadors +who are between the ages of 16 and 30 as + + align:start position:0% +who are between the ages of 16 and 30 as + + + align:start position:0% +who are between the ages of 16 and 30 as +the next generation of climate leaders + + align:start position:0% +the next generation of climate leaders + + + align:start position:0% +the next generation of climate leaders +and educators + + align:start position:0% +and educators + + + align:start position:0% +and educators +the thing about teaching young people in + + align:start position:0% +the thing about teaching young people in + + + align:start position:0% +the thing about teaching young people in +particular + + align:start position:0% +particular + + + align:start position:0% +particular +is that young people are open-minded to + + align:start position:0% +is that young people are open-minded to + + + align:start position:0% +is that young people are open-minded to +new material + + align:start position:0% +new material + + + align:start position:0% +new material +but they're mature enough to understand + + align:start position:0% +but they're mature enough to understand + + + align:start position:0% +but they're mature enough to understand +fairly complex concepts + + align:start position:0% +fairly complex concepts + + + align:start position:0% +fairly complex concepts +they're also part of their parents + + align:start position:0% +they're also part of their parents + + + align:start position:0% +they're also part of their parents +trusted networks so if we can talk to + + align:start position:0% +trusted networks so if we can talk to + + + align:start position:0% +trusted networks so if we can talk to +young people + + align:start position:0% +young people + + + align:start position:0% +young people +they can talk to their parents + + align:start position:0% +they can talk to their parents + + + align:start position:0% +they can talk to their parents +ultimately we hope that + + align:start position:0% +ultimately we hope that + + + align:start position:0% +ultimately we hope that +ambassadors will teach students students + + align:start position:0% +ambassadors will teach students students + + + align:start position:0% +ambassadors will teach students students +will teach families + + align:start position:0% +will teach families + + + align:start position:0% +will teach families +and families will demand action + + align:start position:0% +and families will demand action + + + align:start position:0% +and families will demand action +ultimately i think in creating earth dna + + align:start position:0% +ultimately i think in creating earth dna + + + align:start position:0% +ultimately i think in creating earth dna +ambassadors + + align:start position:0% +ambassadors + + + align:start position:0% +ambassadors +i was really interested in helping + + align:start position:0% +i was really interested in helping + + + align:start position:0% +i was really interested in helping +people who are passionate about climate + + align:start position:0% +people who are passionate about climate + + + align:start position:0% +people who are passionate about climate +change + + align:start position:0% +change + + + align:start position:0% +change +find their own voice and helping them to + + align:start position:0% +find their own voice and helping them to + + + align:start position:0% +find their own voice and helping them to +express + + align:start position:0% +express + + + align:start position:0% +express +their own beliefs and their own opinions + + align:start position:0% +their own beliefs and their own opinions + + + align:start position:0% +their own beliefs and their own opinions +and + + align:start position:0% +and + + + align:start position:0% +and +make a change in their own community i + + align:start position:0% +make a change in their own community i + + + align:start position:0% +make a change in their own community i +think empowering people + + align:start position:0% +think empowering people + + + align:start position:0% +think empowering people +who care about climate change to find + + align:start position:0% +who care about climate change to find + + + align:start position:0% +who care about climate change to find +their voice and use it + + align:start position:0% +their voice and use it + + + align:start position:0% +their voice and use it +has been one of the most rewarding + + align:start position:0% +has been one of the most rewarding + + + align:start position:0% +has been one of the most rewarding +things that i've done and i'm just + + align:start position:0% +things that i've done and i'm just + + + align:start position:0% +things that i've done and i'm just +really grateful for the opportunity + + align:start position:0% +really grateful for the opportunity + + + align:start position:0% +really grateful for the opportunity +to be part of this community of people + + align:start position:0% +to be part of this community of people + + + align:start position:0% +to be part of this community of people +that are + + align:start position:0% +that are + + + align:start position:0% +that are +all interested in self-development in + + align:start position:0% +all interested in self-development in + + + align:start position:0% +all interested in self-development in +leadership and in climate change + + align:start position:0% + + + + align:start position:0% + +in putting the climate 101 presentation + + align:start position:0% +in putting the climate 101 presentation + + + align:start position:0% +in putting the climate 101 presentation +together + + align:start position:0% +together + + + align:start position:0% +together +brandon and the earth dna team didn't + + align:start position:0% +brandon and the earth dna team didn't + + + align:start position:0% +brandon and the earth dna team didn't +want to entirely reinvent the wheel + + align:start position:0% +want to entirely reinvent the wheel + + + align:start position:0% +want to entirely reinvent the wheel +they were open to utilizing many + + align:start position:0% +they were open to utilizing many + + + align:start position:0% +they were open to utilizing many +different materials from a variety of + + align:start position:0% +different materials from a variety of + + + align:start position:0% +different materials from a variety of +reputable sources + + align:start position:0% +reputable sources + + + align:start position:0% +reputable sources +to create a comprehensive experience for + + align:start position:0% +to create a comprehensive experience for + + + align:start position:0% +to create a comprehensive experience for +participants + + align:start position:0% +participants + + + align:start position:0% +participants +and part of what makes it so effective + + align:start position:0% +and part of what makes it so effective + + + align:start position:0% +and part of what makes it so effective +is that the presentation has been + + align:start position:0% +is that the presentation has been + + + align:start position:0% +is that the presentation has been +developed to appeal to a wide audience + + align:start position:0% +developed to appeal to a wide audience + + + align:start position:0% +developed to appeal to a wide audience +whether you're a high school student or + + align:start position:0% +whether you're a high school student or + + + align:start position:0% +whether you're a high school student or +a late career professional + + align:start position:0% +a late career professional + + + align:start position:0% +a late career professional +so most climate change educational + + align:start position:0% +so most climate change educational + + + align:start position:0% +so most climate change educational +materials focus + + align:start position:0% +materials focus + + + align:start position:0% +materials focus +almost exclusively on the science while + + align:start position:0% +almost exclusively on the science while + + + align:start position:0% +almost exclusively on the science while +climate 101 + + align:start position:0% +climate 101 + + + align:start position:0% +climate 101 +covers in 45 minutes the science the + + align:start position:0% +covers in 45 minutes the science the + + + align:start position:0% +covers in 45 minutes the science the +economics and the civics of climate + + align:start position:0% +economics and the civics of climate + + + align:start position:0% +economics and the civics of climate +change + + align:start position:0% +change + + + align:start position:0% +change +and what that allows us to do is to + + align:start position:0% +and what that allows us to do is to + + + align:start position:0% +and what that allows us to do is to +engage with people who wouldn't + + align:start position:0% +engage with people who wouldn't + + + align:start position:0% +engage with people who wouldn't +typically consider climate change to be + + align:start position:0% +typically consider climate change to be + + + align:start position:0% +typically consider climate change to be +one of their first priorities + + align:start position:0% +one of their first priorities + + + align:start position:0% +one of their first priorities +the idea was to create a single + + align:start position:0% +the idea was to create a single + + + align:start position:0% +the idea was to create a single +composition that keeps people's + + align:start position:0% +composition that keeps people's + + + align:start position:0% +composition that keeps people's +attention + + align:start position:0% +attention + + + align:start position:0% +attention +that keeps people engaged that keeps + + align:start position:0% +that keeps people engaged that keeps + + + align:start position:0% +that keeps people engaged that keeps +people interested and excited + + align:start position:0% +people interested and excited + + + align:start position:0% +people interested and excited +while also sharing a large amount of + + align:start position:0% +while also sharing a large amount of + + + align:start position:0% +while also sharing a large amount of +information about climate change from + + align:start position:0% +information about climate change from + + + align:start position:0% +information about climate change from +different perspectives + + align:start position:0% +different perspectives + + + align:start position:0% +different perspectives +and i think that's what climate 101 has + + align:start position:0% +and i think that's what climate 101 has + + + align:start position:0% +and i think that's what climate 101 has +accomplished + + align:start position:0% +accomplished + + + align:start position:0% +accomplished +and earth dna has data to back that up + + align:start position:0% +and earth dna has data to back that up + + + align:start position:0% +and earth dna has data to back that up +surveys they've collected + + align:start position:0% +surveys they've collected + + + align:start position:0% +surveys they've collected +show that before the presentation about + + align:start position:0% +show that before the presentation about + + + align:start position:0% +show that before the presentation about +half of the students talked with their + + align:start position:0% +half of the students talked with their + + + align:start position:0% +half of the students talked with their +friends or family about climate change + + align:start position:0% +friends or family about climate change + + + align:start position:0% +friends or family about climate change +twice a week but afterward the number of + + align:start position:0% +twice a week but afterward the number of + + + align:start position:0% +twice a week but afterward the number of +people participating in those + + align:start position:0% +people participating in those + + + align:start position:0% +people participating in those +conversations + + align:start position:0% +conversations + + + align:start position:0% +conversations +jumped to over 80 percent sometimes + + align:start position:0% +jumped to over 80 percent sometimes + + + align:start position:0% +jumped to over 80 percent sometimes +those conversations can be difficult + + align:start position:0% +those conversations can be difficult + + + align:start position:0% +those conversations can be difficult +especially when they're with people who + + align:start position:0% +especially when they're with people who + + + align:start position:0% +especially when they're with people who +are skeptical about climate change + + align:start position:0% +are skeptical about climate change + + + align:start position:0% +are skeptical about climate change +but climate 101 helps ambassadors with + + align:start position:0% +but climate 101 helps ambassadors with + + + align:start position:0% +but climate 101 helps ambassadors with +that too + + align:start position:0% +that too + + + align:start position:0% +that too +when it comes to climate change even the + + align:start position:0% +when it comes to climate change even the + + + align:start position:0% +when it comes to climate change even the +stories of what's happening + + align:start position:0% +stories of what's happening + + + align:start position:0% +stories of what's happening +is very different right we have + + align:start position:0% +is very different right we have + + + align:start position:0% +is very different right we have +different interpretations + + align:start position:0% +different interpretations + + + align:start position:0% +different interpretations +of different facts that lead us to + + align:start position:0% +of different facts that lead us to + + + align:start position:0% +of different facts that lead us to +different conclusions + + align:start position:0% +different conclusions + + + align:start position:0% +different conclusions +and then we often argue about those + + align:start position:0% +and then we often argue about those + + + align:start position:0% +and then we often argue about those +conclusions without understanding each + + align:start position:0% +conclusions without understanding each + + + align:start position:0% +conclusions without understanding each +other's interpretations or the + + align:start position:0% +other's interpretations or the + + + align:start position:0% +other's interpretations or the +observations that each of us have made + + align:start position:0% +observations that each of us have made + + + align:start position:0% +observations that each of us have made +and so even in bringing up a climate + + align:start position:0% +and so even in bringing up a climate + + + align:start position:0% +and so even in bringing up a climate +change conversation + + align:start position:0% +change conversation + + + align:start position:0% +change conversation +you have to be aware that you might be + + align:start position:0% +you have to be aware that you might be + + + align:start position:0% +you have to be aware that you might be +threatening the way that somebody sees + + align:start position:0% +threatening the way that somebody sees + + + align:start position:0% +threatening the way that somebody sees +themselves + + align:start position:0% +themselves + + + align:start position:0% +themselves +or maybe in engaging in these + + align:start position:0% +or maybe in engaging in these + + + align:start position:0% +or maybe in engaging in these +conversations you are threatening + + align:start position:0% +conversations you are threatening + + + align:start position:0% +conversations you are threatening +somebody's sense of patriotism + + align:start position:0% +somebody's sense of patriotism + + + align:start position:0% +somebody's sense of patriotism +or sense of being a good person + + align:start position:0% +or sense of being a good person + + + align:start position:0% +or sense of being a good person +especially in areas where the economy is + + align:start position:0% +especially in areas where the economy is + + + align:start position:0% +especially in areas where the economy is +based in + + align:start position:0% +based in + + + align:start position:0% +based in +fossil fuels it can be really difficult + + align:start position:0% +fossil fuels it can be really difficult + + + align:start position:0% +fossil fuels it can be really difficult +because ultimately a climate change + + align:start position:0% +because ultimately a climate change + + + align:start position:0% +because ultimately a climate change +conversation + + align:start position:0% +conversation + + + align:start position:0% +conversation +can amount to an accusation that that + + align:start position:0% +can amount to an accusation that that + + + align:start position:0% +can amount to an accusation that that +person is not just + + align:start position:0% +person is not just + + + align:start position:0% +person is not just +providing food for their family but also + + align:start position:0% +providing food for their family but also + + + align:start position:0% +providing food for their family but also +is damaging the earth and + + align:start position:0% +is damaging the earth and + + + align:start position:0% +is damaging the earth and +harming a lot of people and so it's + + align:start position:0% +harming a lot of people and so it's + + + align:start position:0% +harming a lot of people and so it's +really important to consider all of + + align:start position:0% +really important to consider all of + + + align:start position:0% +really important to consider all of +those + + align:start position:0% +those + + + align:start position:0% +those +things as you have these climate change + + align:start position:0% +things as you have these climate change + + + align:start position:0% +things as you have these climate change +conversations + + align:start position:0% +conversations + + + align:start position:0% +conversations +so instead of trying to convince the + + align:start position:0% +so instead of trying to convince the + + + align:start position:0% +so instead of trying to convince the +other person or persuade the other + + align:start position:0% +other person or persuade the other + + + align:start position:0% +other person or persuade the other +person + + align:start position:0% +person + + + align:start position:0% +person +listen help them empty their heart + + align:start position:0% +listen help them empty their heart + + + align:start position:0% +listen help them empty their heart +and express why they're frustrated with + + align:start position:0% +and express why they're frustrated with + + + align:start position:0% +and express why they're frustrated with +a situation and then they'll be more + + align:start position:0% +a situation and then they'll be more + + + align:start position:0% +a situation and then they'll be more +likely to listen to your own experiences + + align:start position:0% +likely to listen to your own experiences + + + align:start position:0% +likely to listen to your own experiences +and more receptive to why you think + + align:start position:0% +and more receptive to why you think + + + align:start position:0% +and more receptive to why you think +climate change + + align:start position:0% +climate change + + + align:start position:0% +climate change +matters and is relevant + + align:start position:0% +matters and is relevant + + + align:start position:0% +matters and is relevant +[Music] + + align:start position:0% + + + + align:start position:0% + +something else that helps the climate + + align:start position:0% +something else that helps the climate + + + align:start position:0% +something else that helps the climate +101 presentation resonate across + + align:start position:0% +101 presentation resonate across + + + align:start position:0% +101 presentation resonate across +different audiences + + align:start position:0% +different audiences + + + align:start position:0% +different audiences +is the incorporation of local insights + + align:start position:0% +is the incorporation of local insights + + + align:start position:0% +is the incorporation of local insights +this targeted approach helps distill the + + align:start position:0% +this targeted approach helps distill the + + + align:start position:0% +this targeted approach helps distill the +larger sometimes overwhelming issue of + + align:start position:0% +larger sometimes overwhelming issue of + + + align:start position:0% +larger sometimes overwhelming issue of +climate change + + align:start position:0% +climate change + + + align:start position:0% +climate change +into something more digestible one of + + align:start position:0% +into something more digestible one of + + + align:start position:0% +into something more digestible one of +the problems with climate change + + align:start position:0% +the problems with climate change + + + align:start position:0% +the problems with climate change +discussions is that it's a huge problem + + align:start position:0% +discussions is that it's a huge problem + + + align:start position:0% +discussions is that it's a huge problem +right it affects the entire world and + + align:start position:0% +right it affects the entire world and + + + align:start position:0% +right it affects the entire world and +that happens over the course of decades + + align:start position:0% +that happens over the course of decades + + + align:start position:0% +that happens over the course of decades +but people live their lives at home or + + align:start position:0% +but people live their lives at home or + + + align:start position:0% +but people live their lives at home or +in their town + + align:start position:0% +in their town + + + align:start position:0% +in their town +and people live their lives day to day + + align:start position:0% +and people live their lives day to day + + + align:start position:0% +and people live their lives day to day +so when you start talking about these + + align:start position:0% +so when you start talking about these + + + align:start position:0% +so when you start talking about these +massive overwhelming changes + + align:start position:0% +massive overwhelming changes + + + align:start position:0% +massive overwhelming changes +it can be really easy to just dismiss + + align:start position:0% +it can be really easy to just dismiss + + + align:start position:0% +it can be really easy to just dismiss +them as either things + + align:start position:0% +them as either things + + + align:start position:0% +them as either things +that don't affect me or things that i + + align:start position:0% +that don't affect me or things that i + + + align:start position:0% +that don't affect me or things that i +can't do anything about + + align:start position:0% +can't do anything about + + + align:start position:0% +can't do anything about +the idea of creating localized insights + + align:start position:0% +the idea of creating localized insights + + + align:start position:0% +the idea of creating localized insights +and personally meaningful insights is + + align:start position:0% +and personally meaningful insights is + + + align:start position:0% +and personally meaningful insights is +that we need to talk about climate + + align:start position:0% +that we need to talk about climate + + + align:start position:0% +that we need to talk about climate +change in a way that's relevant + + align:start position:0% +change in a way that's relevant + + + align:start position:0% +change in a way that's relevant +to the intended audience and so if we + + align:start position:0% +to the intended audience and so if we + + + align:start position:0% +to the intended audience and so if we +can say for example + + align:start position:0% +can say for example + + + align:start position:0% +can say for example +well here in boston the city was + + align:start position:0% +well here in boston the city was + + + align:start position:0% +well here in boston the city was +actually considering building sea walls + + align:start position:0% +actually considering building sea walls + + + align:start position:0% +actually considering building sea walls +because of anticipated flooding now all + + align:start position:0% +because of anticipated flooding now all + + + align:start position:0% +because of anticipated flooding now all +of a sudden that's something that's + + align:start position:0% +of a sudden that's something that's + + + align:start position:0% +of a sudden that's something that's +happening in my neighborhood + + align:start position:0% +happening in my neighborhood + + + align:start position:0% +happening in my neighborhood +that's something that's like oh my god + + align:start position:0% +that's something that's like oh my god + + + align:start position:0% +that's something that's like oh my god +that's coming for me + + align:start position:0% +that's coming for me + + + align:start position:0% +that's coming for me +that's not the earth is warming by two + + align:start position:0% +that's not the earth is warming by two + + + align:start position:0% +that's not the earth is warming by two +degrees celsius which doesn't really + + align:start position:0% +degrees celsius which doesn't really + + + align:start position:0% +degrees celsius which doesn't really +mean much to me it's + + align:start position:0% +mean much to me it's + + + align:start position:0% +mean much to me it's +oh my god there's going to be flooding + + align:start position:0% +oh my god there's going to be flooding + + + align:start position:0% +oh my god there's going to be flooding +in boston + + align:start position:0% +in boston + + + align:start position:0% +in boston +the more i talked with brandon the more + + align:start position:0% +the more i talked with brandon the more + + + align:start position:0% +the more i talked with brandon the more +i wanted to know what was personally + + align:start position:0% +i wanted to know what was personally + + + align:start position:0% +i wanted to know what was personally +motivating him + + align:start position:0% +motivating him + + + align:start position:0% +motivating him +to engage in climate action work he + + align:start position:0% +to engage in climate action work he + + + align:start position:0% +to engage in climate action work he +began to talk about the + + align:start position:0% +began to talk about the + + + align:start position:0% +began to talk about the +intergenerational experiences + + align:start position:0% +intergenerational experiences + + + align:start position:0% +intergenerational experiences +of his own family a few years ago + + align:start position:0% +of his own family a few years ago + + + align:start position:0% +of his own family a few years ago +my family celebrated its 25th + + align:start position:0% +my family celebrated its 25th + + + align:start position:0% +my family celebrated its 25th +anniversary in the united states + + align:start position:0% +anniversary in the united states + + + align:start position:0% +anniversary in the united states +we were all at my grandparents place + + align:start position:0% +we were all at my grandparents place + + + align:start position:0% +we were all at my grandparents place +seated around this beautiful dining room + + align:start position:0% +seated around this beautiful dining room + + + align:start position:0% +seated around this beautiful dining room +table + + align:start position:0% +table + + + align:start position:0% +table +in front of a gorgeous display case full + + align:start position:0% +in front of a gorgeous display case full + + + align:start position:0% +in front of a gorgeous display case full +of fancy china + + align:start position:0% +of fancy china + + + align:start position:0% +of fancy china +and my grandma was bustling around + + align:start position:0% +and my grandma was bustling around + + + align:start position:0% +and my grandma was bustling around +making sure we all had enough of that + + align:start position:0% +making sure we all had enough of that + + + align:start position:0% +making sure we all had enough of that +fatty and meaty ukrainian food that my + + align:start position:0% +fatty and meaty ukrainian food that my + + + align:start position:0% +fatty and meaty ukrainian food that my +family loves + + align:start position:0% +family loves + + + align:start position:0% +family loves +and my family was telling stories + + align:start position:0% +and my family was telling stories + + + align:start position:0% +and my family was telling stories +stories of my childhood that i'd been + + align:start position:0% +stories of my childhood that i'd been + + + align:start position:0% +stories of my childhood that i'd been +hearing for years + + align:start position:0% +hearing for years + + + align:start position:0% +hearing for years +but stories that helped us reflect on + + align:start position:0% +but stories that helped us reflect on + + + align:start position:0% +but stories that helped us reflect on +what it meant to come to the united + + align:start position:0% +what it meant to come to the united + + + align:start position:0% +what it meant to come to the united +states + + align:start position:0% +states + + + align:start position:0% +states +my grandpa told how he'd only taken one + + align:start position:0% +my grandpa told how he'd only taken one + + + align:start position:0% +my grandpa told how he'd only taken one +flight in his whole life + + align:start position:0% +flight in his whole life + + + align:start position:0% +flight in his whole life +and it was to come to the united states + + align:start position:0% +and it was to come to the united states + + + align:start position:0% +and it was to come to the united states +because the only thing that he feared + + align:start position:0% +because the only thing that he feared + + + align:start position:0% +because the only thing that he feared +more than flying was staying in a + + align:start position:0% +more than flying was staying in a + + + align:start position:0% +more than flying was staying in a +collapsed soviet state + + align:start position:0% +collapsed soviet state + + + align:start position:0% +collapsed soviet state +my grandma how she came to the u.s + + align:start position:0% +my grandma how she came to the u.s + + + align:start position:0% +my grandma how she came to the u.s +without knowing any english and not only + + align:start position:0% +without knowing any english and not only + + + align:start position:0% +without knowing any english and not only +learned english but also learned how to + + align:start position:0% +learned english but also learned how to + + + align:start position:0% +learned english but also learned how to +code + + align:start position:0% +code + + + align:start position:0% +code +and recently retired as a senior + + align:start position:0% +and recently retired as a senior + + + align:start position:0% +and recently retired as a senior +software developer + + align:start position:0% +software developer + + + align:start position:0% +software developer +my mom how she after four months here + + align:start position:0% +my mom how she after four months here + + + align:start position:0% +my mom how she after four months here +was caught stealing a seven dollar + + align:start position:0% +was caught stealing a seven dollar + + + align:start position:0% +was caught stealing a seven dollar +bottle of face cream + + align:start position:0% +bottle of face cream + + + align:start position:0% +bottle of face cream +because she wanted to get a gift for her + + align:start position:0% +because she wanted to get a gift for her + + + align:start position:0% +because she wanted to get a gift for her +mom's birthday and she couldn't afford + + align:start position:0% +mom's birthday and she couldn't afford + + + align:start position:0% +mom's birthday and she couldn't afford +it + + align:start position:0% +it + + + align:start position:0% +it +now my mom went on and started a + + align:start position:0% +now my mom went on and started a + + + align:start position:0% +now my mom went on and started a +business that ended up putting me + + align:start position:0% +business that ended up putting me + + + align:start position:0% +business that ended up putting me +through college + + align:start position:0% +through college + + + align:start position:0% +through college +but even 25 years later she was still so + + align:start position:0% +but even 25 years later she was still so + + + align:start position:0% +but even 25 years later she was still so +embarrassed and ashamed of that moment + + align:start position:0% +embarrassed and ashamed of that moment + + + align:start position:0% +embarrassed and ashamed of that moment +i turned to my dad and i asked him + + align:start position:0% +i turned to my dad and i asked him + + + align:start position:0% +i turned to my dad and i asked him +whether he ever missed + + align:start position:0% +whether he ever missed + + + align:start position:0% +whether he ever missed +the ukraine it's where he grew up it's + + align:start position:0% +the ukraine it's where he grew up it's + + + align:start position:0% +the ukraine it's where he grew up it's +where his friends + + align:start position:0% +where his friends + + + align:start position:0% +where his friends +are and he turned to me and responded in + + align:start position:0% +are and he turned to me and responded in + + + align:start position:0% +are and he turned to me and responded in +russian + + align:start position:0% +russian + + + align:start position:0% +russian +that only in his worst nightmare would + + align:start position:0% +that only in his worst nightmare would + + + align:start position:0% +that only in his worst nightmare would +he ever wake up back in that hell + + align:start position:0% +he ever wake up back in that hell + + + align:start position:0% +he ever wake up back in that hell +and to me that moment really + + align:start position:0% +and to me that moment really + + + align:start position:0% +and to me that moment really +crystallizes this idea that so much + + align:start position:0% +crystallizes this idea that so much + + + align:start position:0% +crystallizes this idea that so much +of who we are and what we have is + + align:start position:0% +of who we are and what we have is + + + align:start position:0% +of who we are and what we have is +determined + + align:start position:0% +determined + + + align:start position:0% +determined +by choices that people make before we're + + align:start position:0% +by choices that people make before we're + + + align:start position:0% +by choices that people make before we're +even born and that's just + + align:start position:0% +even born and that's just + + + align:start position:0% +even born and that's just +such a great injustice and + + align:start position:0% +such a great injustice and + + + align:start position:0% +such a great injustice and +climate change exemplifies that i think + + align:start position:0% +climate change exemplifies that i think + + + align:start position:0% +climate change exemplifies that i think +climate change is + + align:start position:0% +climate change is + + + align:start position:0% +climate change is +one of the great injustices of our time + + align:start position:0% +one of the great injustices of our time + + + align:start position:0% +one of the great injustices of our time +it was created primarily by wealthy + + align:start position:0% +it was created primarily by wealthy + + + align:start position:0% +it was created primarily by wealthy +privileged people in developed nations + + align:start position:0% +privileged people in developed nations + + + align:start position:0% +privileged people in developed nations +and it will primarily affect the + + align:start position:0% +and it will primarily affect the + + + align:start position:0% +and it will primarily affect the +vulnerable the poor + + align:start position:0% +vulnerable the poor + + + align:start position:0% +vulnerable the poor +the sick in many cases people who never + + align:start position:0% +the sick in many cases people who never + + + align:start position:0% +the sick in many cases people who never +even contributed to the problem + + align:start position:0% +even contributed to the problem + + + align:start position:0% +even contributed to the problem +i think that for those of us who have an + + align:start position:0% +i think that for those of us who have an + + + align:start position:0% +i think that for those of us who have an +opportunity + + align:start position:0% +opportunity + + + align:start position:0% +opportunity +to fight that injustice for those of us + + align:start position:0% +to fight that injustice for those of us + + + align:start position:0% +to fight that injustice for those of us +who have benefited + + align:start position:0% +who have benefited + + + align:start position:0% +who have benefited +from being fortunate and from being born + + align:start position:0% +from being fortunate and from being born + + + align:start position:0% +from being fortunate and from being born +in the right place at the right time + + align:start position:0% +in the right place at the right time + + + align:start position:0% +in the right place at the right time +we have a real obligation to help the + + align:start position:0% +we have a real obligation to help the + + + align:start position:0% +we have a real obligation to help the +people + + align:start position:0% +people + + + align:start position:0% +people +who don't necessarily have those + + align:start position:0% +who don't necessarily have those + + + align:start position:0% +who don't necessarily have those +opportunities now reach those same + + align:start position:0% +opportunities now reach those same + + + align:start position:0% +opportunities now reach those same +opportunities + + align:start position:0% +opportunities + + + align:start position:0% +opportunities +and in this case it means doing + + align:start position:0% +and in this case it means doing + + + align:start position:0% +and in this case it means doing +something about + + align:start position:0% +something about + + + align:start position:0% +something about +this massive global problem that will + + align:start position:0% +this massive global problem that will + + + align:start position:0% +this massive global problem that will +eventually affect all of us but is + + align:start position:0% +eventually affect all of us but is + + + align:start position:0% +eventually affect all of us but is +already affecting + + align:start position:0% +already affecting + + + align:start position:0% +already affecting +many of the most vulnerable + + align:start position:0% + + + + align:start position:0% + +one important component in tackling + + align:start position:0% +one important component in tackling + + + align:start position:0% +one important component in tackling +climate change + + align:start position:0% +climate change + + + align:start position:0% +climate change +is recognizing that it's a collective + + align:start position:0% +is recognizing that it's a collective + + + align:start position:0% +is recognizing that it's a collective +issue that affects just about everyone + + align:start position:0% +issue that affects just about everyone + + + align:start position:0% +issue that affects just about everyone +brandon incorporated interactive + + align:start position:0% +brandon incorporated interactive + + + align:start position:0% +brandon incorporated interactive +activities into the climate 101 + + align:start position:0% +activities into the climate 101 + + + align:start position:0% +activities into the climate 101 +curriculum + + align:start position:0% +curriculum + + + align:start position:0% +curriculum +to help simulate how these collective + + align:start position:0% +to help simulate how these collective + + + align:start position:0% +to help simulate how these collective +dilemmas can play out + + align:start position:0% +dilemmas can play out + + + align:start position:0% +dilemmas can play out +these activities are modeled on the + + align:start position:0% +these activities are modeled on the + + + align:start position:0% +these activities are modeled on the +concept of the tragedy of the commons + + align:start position:0% +concept of the tragedy of the commons + + + align:start position:0% +concept of the tragedy of the commons +where people tend to act selfishly when + + align:start position:0% +where people tend to act selfishly when + + + align:start position:0% +where people tend to act selfishly when +they believe that their individual + + align:start position:0% +they believe that their individual + + + align:start position:0% +they believe that their individual +actions + + align:start position:0% +actions + + + align:start position:0% +actions +won't make an impact a classic example + + align:start position:0% +won't make an impact a classic example + + + align:start position:0% +won't make an impact a classic example +of the tragedy of the commons + + align:start position:0% +of the tragedy of the commons + + + align:start position:0% +of the tragedy of the commons +is the gradual overfishing of a public + + align:start position:0% +is the gradual overfishing of a public + + + align:start position:0% +is the gradual overfishing of a public +waterway + + align:start position:0% +waterway + + + align:start position:0% +waterway +and in some ways this concept mirrors + + align:start position:0% +and in some ways this concept mirrors + + + align:start position:0% +and in some ways this concept mirrors +what we've seen throughout the kovit 19 + + align:start position:0% +what we've seen throughout the kovit 19 + + + align:start position:0% +what we've seen throughout the kovit 19 +pandemic + + align:start position:0% +pandemic + + + align:start position:0% +pandemic +while these issues are quite different + + align:start position:0% +while these issues are quite different + + + align:start position:0% +while these issues are quite different +of course they do both require + + align:start position:0% +of course they do both require + + + align:start position:0% +of course they do both require +collaborative efforts to make a real + + align:start position:0% +collaborative efforts to make a real + + + align:start position:0% +collaborative efforts to make a real +difference in tackling them + + align:start position:0% +difference in tackling them + + + align:start position:0% +difference in tackling them +and our everyday choices actually can + + align:start position:0% +and our everyday choices actually can + + + align:start position:0% +and our everyday choices actually can +have an immediate impact + + align:start position:0% +have an immediate impact + + + align:start position:0% +have an immediate impact +i think covid is a really great example + + align:start position:0% +i think covid is a really great example + + + align:start position:0% +i think covid is a really great example +of collective dilemmas + + align:start position:0% +of collective dilemmas + + + align:start position:0% +of collective dilemmas +and in the us in particular we have this + + align:start position:0% +and in the us in particular we have this + + + align:start position:0% +and in the us in particular we have this +very individualist attitude + + align:start position:0% +very individualist attitude + + + align:start position:0% +very individualist attitude +personal liberty above all else and + + align:start position:0% +personal liberty above all else and + + + align:start position:0% +personal liberty above all else and +personal liberty is + + align:start position:0% +personal liberty is + + + align:start position:0% +personal liberty is +obviously super important but we see in + + align:start position:0% +obviously super important but we see in + + + align:start position:0% +obviously super important but we see in +a case like kovid + + align:start position:0% +a case like kovid + + + align:start position:0% +a case like kovid +that when crises arise sometimes + + align:start position:0% +that when crises arise sometimes + + + align:start position:0% +that when crises arise sometimes +we do need to act for the collective + + align:start position:0% +we do need to act for the collective + + + align:start position:0% +we do need to act for the collective +good and that can be really difficult + + align:start position:0% +good and that can be really difficult + + + align:start position:0% +good and that can be really difficult +but climate change is similar the longer + + align:start position:0% +but climate change is similar the longer + + + align:start position:0% +but climate change is similar the longer +we waited to take action on kovid + + align:start position:0% +we waited to take action on kovid + + + align:start position:0% +we waited to take action on kovid +the more drastic the action had to be + + align:start position:0% +the more drastic the action had to be + + + align:start position:0% +the more drastic the action had to be +and with climate change it's similar + + align:start position:0% +and with climate change it's similar + + + align:start position:0% +and with climate change it's similar +had we started really focusing on + + align:start position:0% +had we started really focusing on + + + align:start position:0% +had we started really focusing on +reducing our emissions and transitioning + + align:start position:0% +reducing our emissions and transitioning + + + align:start position:0% +reducing our emissions and transitioning +to renewable energy + + align:start position:0% +to renewable energy + + + align:start position:0% +to renewable energy +as well as making some of the other + + align:start position:0% +as well as making some of the other + + + align:start position:0% +as well as making some of the other +changes we need to make in + + align:start position:0% +changes we need to make in + + + align:start position:0% +changes we need to make in +2000 we could have done it pretty + + align:start position:0% +2000 we could have done it pretty + + + align:start position:0% +2000 we could have done it pretty +gradually and at a reasonable pace + + align:start position:0% +gradually and at a reasonable pace + + + align:start position:0% +gradually and at a reasonable pace +but we waited 20 years and it looks like + + align:start position:0% +but we waited 20 years and it looks like + + + align:start position:0% +but we waited 20 years and it looks like +we're still waiting + + align:start position:0% +we're still waiting + + + align:start position:0% +we're still waiting +so now the action that we have to take + + align:start position:0% +so now the action that we have to take + + + align:start position:0% +so now the action that we have to take +is much more drastic + + align:start position:0% +is much more drastic + + + align:start position:0% +is much more drastic +than had we done it 20 years ago and if + + align:start position:0% +than had we done it 20 years ago and if + + + align:start position:0% +than had we done it 20 years ago and if +we continue to wait + + align:start position:0% +we continue to wait + + + align:start position:0% +we continue to wait +that action will have to be still more + + align:start position:0% +that action will have to be still more + + + align:start position:0% +that action will have to be still more +drastic + + align:start position:0% +drastic + + + align:start position:0% +drastic +so yesterday is better than today and + + align:start position:0% +so yesterday is better than today and + + + align:start position:0% +so yesterday is better than today and +today is better than tomorrow + + align:start position:0% +today is better than tomorrow + + + align:start position:0% +today is better than tomorrow +to quote one of the articles that i read + + align:start position:0% +to quote one of the articles that i read + + + align:start position:0% +to quote one of the articles that i read +regarding kovid + + align:start position:0% +regarding kovid + + + align:start position:0% +regarding kovid +but that also applies equally well to + + align:start position:0% +but that also applies equally well to + + + align:start position:0% +but that also applies equally well to +climate change + + align:start position:0% + + + + align:start position:0% + +many people worry that attention on + + align:start position:0% +many people worry that attention on + + + align:start position:0% +many people worry that attention on +climate change has weakened due to the + + align:start position:0% +climate change has weakened due to the + + + align:start position:0% +climate change has weakened due to the +covet 19 pandemic + + align:start position:0% +covet 19 pandemic + + + align:start position:0% +covet 19 pandemic +but brandon sees a space for optimism + + align:start position:0% +but brandon sees a space for optimism + + + align:start position:0% +but brandon sees a space for optimism +and views these overlapping crises + + align:start position:0% +and views these overlapping crises + + + align:start position:0% +and views these overlapping crises +as an opportunity i think for a lot of + + align:start position:0% +as an opportunity i think for a lot of + + + align:start position:0% +as an opportunity i think for a lot of +climate activists right now is + + align:start position:0% +climate activists right now is + + + align:start position:0% +climate activists right now is +difficult in terms of climate activism + + align:start position:0% +difficult in terms of climate activism + + + align:start position:0% +difficult in terms of climate activism +because + + align:start position:0% +because + + + align:start position:0% +because +covet is a really serious and really + + align:start position:0% +covet is a really serious and really + + + align:start position:0% +covet is a really serious and really +urgent problem + + align:start position:0% +urgent problem + + + align:start position:0% +urgent problem +and it can be hard to spare any + + align:start position:0% +and it can be hard to spare any + + + align:start position:0% +and it can be hard to spare any +attention or any emotion + + align:start position:0% +attention or any emotion + + + align:start position:0% +attention or any emotion +for climate change this other scary + + align:start position:0% +for climate change this other scary + + + align:start position:0% +for climate change this other scary +thing but times of crisis are actually + + align:start position:0% +thing but times of crisis are actually + + + align:start position:0% +thing but times of crisis are actually +times of opportunity + + align:start position:0% +times of opportunity + + + align:start position:0% +times of opportunity +and so right now is a time that people + + align:start position:0% +and so right now is a time that people + + + align:start position:0% +and so right now is a time that people +feel like they need connection and + + align:start position:0% +feel like they need connection and + + + align:start position:0% +feel like they need connection and +purpose + + align:start position:0% +purpose + + + align:start position:0% +purpose +and community and so right now is an + + align:start position:0% +and community and so right now is an + + + align:start position:0% +and community and so right now is an +opportunity for us to continue growing + + align:start position:0% +opportunity for us to continue growing + + + align:start position:0% +opportunity for us to continue growing +and giving people those things and it's + + align:start position:0% +and giving people those things and it's + + + align:start position:0% +and giving people those things and it's +also an opportunity to fight even harder + + align:start position:0% +also an opportunity to fight even harder + + + align:start position:0% +also an opportunity to fight even harder +for some of the changes that we need to + + align:start position:0% +for some of the changes that we need to + + + align:start position:0% +for some of the changes that we need to +make in order to + + align:start position:0% +make in order to + + + align:start position:0% +make in order to +overcome the climate change issue as + + align:start position:0% +overcome the climate change issue as + + + align:start position:0% +overcome the climate change issue as +well as the covet issue + + align:start position:0% +well as the covet issue + + + align:start position:0% +well as the covet issue +much of brandon's work around this + + align:start position:0% +much of brandon's work around this + + + align:start position:0% +much of brandon's work around this +project which inspires others to take a + + align:start position:0% +project which inspires others to take a + + + align:start position:0% +project which inspires others to take a +leadership role in their own way + + align:start position:0% +leadership role in their own way + + + align:start position:0% +leadership role in their own way +has been driven by his own experiences + + align:start position:0% +has been driven by his own experiences + + + align:start position:0% +has been driven by his own experiences +with leaders in his life + + align:start position:0% +with leaders in his life + + + align:start position:0% +with leaders in his life +throughout the covet 19 pandemic he's + + align:start position:0% +throughout the covet 19 pandemic he's + + + align:start position:0% +throughout the covet 19 pandemic he's +found strong leaders and his advisor + + align:start position:0% +found strong leaders and his advisor + + + align:start position:0% +found strong leaders and his advisor +professor david newman at mit + + align:start position:0% +professor david newman at mit + + + align:start position:0% +professor david newman at mit +who you heard from in our last episode + + align:start position:0% +who you heard from in our last episode + + + align:start position:0% +who you heard from in our last episode +and rand wentworth + + align:start position:0% +and rand wentworth + + + align:start position:0% +and rand wentworth +brandon's environmental leadership + + align:start position:0% +brandon's environmental leadership + + + align:start position:0% +brandon's environmental leadership +professor at the harvard kennedy school + + align:start position:0% +professor at the harvard kennedy school + + + align:start position:0% +professor at the harvard kennedy school +they have both been such incredible + + align:start position:0% +they have both been such incredible + + + align:start position:0% +they have both been such incredible +models of what it means to be a leader + + align:start position:0% +models of what it means to be a leader + + + align:start position:0% +models of what it means to be a leader +during a crisis + + align:start position:0% +during a crisis + + + align:start position:0% +during a crisis +they have been hyper attentive to their + + align:start position:0% +they have been hyper attentive to their + + + align:start position:0% +they have been hyper attentive to their +students needs + + align:start position:0% +students needs + + + align:start position:0% +students needs +so empathetic such good listeners + + align:start position:0% +so empathetic such good listeners + + + align:start position:0% +so empathetic such good listeners +adaptive and flexible and positive + + align:start position:0% +adaptive and flexible and positive + + + align:start position:0% +adaptive and flexible and positive +and that has been really inspiring for + + align:start position:0% +and that has been really inspiring for + + + align:start position:0% +and that has been really inspiring for +me + + align:start position:0% +me + + + align:start position:0% +me +empathy is everything and it's just so + + align:start position:0% +empathy is everything and it's just so + + + align:start position:0% +empathy is everything and it's just so +hard right now + + align:start position:0% +hard right now + + + align:start position:0% +hard right now +you know my emotional reserves that i + + align:start position:0% +you know my emotional reserves that i + + + align:start position:0% +you know my emotional reserves that i +usually + + align:start position:0% +usually + + + align:start position:0% +usually +use to accomplish tasks that i don't + + align:start position:0% +use to accomplish tasks that i don't + + + align:start position:0% +use to accomplish tasks that i don't +necessarily find is interesting + + align:start position:0% +necessarily find is interesting + + + align:start position:0% +necessarily find is interesting +are gone at this point i'm just hyper + + align:start position:0% +are gone at this point i'm just hyper + + + align:start position:0% +are gone at this point i'm just hyper +focused on staying sane + + align:start position:0% +focused on staying sane + + + align:start position:0% +focused on staying sane +staying happy staying healthy and + + align:start position:0% +staying happy staying healthy and + + + align:start position:0% +staying happy staying healthy and +rand and deva both really understand + + align:start position:0% +rand and deva both really understand + + + align:start position:0% +rand and deva both really understand +that and they start every meeting + + align:start position:0% +that and they start every meeting + + + align:start position:0% +that and they start every meeting +with a check-in how are you guys what + + align:start position:0% +with a check-in how are you guys what + + + align:start position:0% +with a check-in how are you guys what +can i do to help + + align:start position:0% +can i do to help + + + align:start position:0% +can i do to help +and that's something that i hope to take + + align:start position:0% +and that's something that i hope to take + + + align:start position:0% +and that's something that i hope to take +forward + + align:start position:0% +forward + + + align:start position:0% +forward +as an immediate response in a crisis + + align:start position:0% +as an immediate response in a crisis + + + align:start position:0% +as an immediate response in a crisis +is to figure out okay how are the people + + align:start position:0% +is to figure out okay how are the people + + + align:start position:0% +is to figure out okay how are the people +that are affected by this crisis + + align:start position:0% +that are affected by this crisis + + + align:start position:0% +that are affected by this crisis +doing and what can i do to accommodate + + align:start position:0% +doing and what can i do to accommodate + + + align:start position:0% +doing and what can i do to accommodate +them and to make it easier + + align:start position:0% +them and to make it easier + + + align:start position:0% +them and to make it easier +for them brandon understands that many + + align:start position:0% +for them brandon understands that many + + + align:start position:0% +for them brandon understands that many +people + + align:start position:0% +people + + + align:start position:0% +people +when faced with the covet 19 pandemic as + + align:start position:0% +when faced with the covet 19 pandemic as + + + align:start position:0% +when faced with the covet 19 pandemic as +well as the threat of climate change are + + align:start position:0% +well as the threat of climate change are + + + align:start position:0% +well as the threat of climate change are +experiencing a kind of + + align:start position:0% +experiencing a kind of + + + align:start position:0% +experiencing a kind of +doom fatigue if you seek it out there + + align:start position:0% +doom fatigue if you seek it out there + + + align:start position:0% +doom fatigue if you seek it out there +can be an + + align:start position:0% +can be an + + + align:start position:0% +can be an +overwhelming amount of bad news about + + align:start position:0% +overwhelming amount of bad news about + + + align:start position:0% +overwhelming amount of bad news about +both crises + + align:start position:0% +both crises + + + align:start position:0% +both crises +but brandon is working on reframing this + + align:start position:0% +but brandon is working on reframing this + + + align:start position:0% +but brandon is working on reframing this +thinking into something more + + align:start position:0% +thinking into something more + + + align:start position:0% +thinking into something more +approachable + + align:start position:0% +approachable + + + align:start position:0% +approachable +so that people can carry forward with + + align:start position:0% +so that people can carry forward with + + + align:start position:0% +so that people can carry forward with +important work in their own + + align:start position:0% +important work in their own + + + align:start position:0% +important work in their own +manageable way without feeling like it's + + align:start position:0% +manageable way without feeling like it's + + + align:start position:0% +manageable way without feeling like it's +all just too much to handle + + align:start position:0% +all just too much to handle + + + align:start position:0% +all just too much to handle +there are definitely times when i also + + align:start position:0% +there are definitely times when i also + + + align:start position:0% +there are definitely times when i also +feel like + + align:start position:0% +feel like + + + align:start position:0% +feel like +why am i even bothering there's so + + align:start position:0% +why am i even bothering there's so + + + align:start position:0% +why am i even bothering there's so +much out there to improve + + align:start position:0% +much out there to improve + + + align:start position:0% +much out there to improve +what can i do there's a story + + align:start position:0% +what can i do there's a story + + + align:start position:0% +what can i do there's a story +that i love it's + + align:start position:0% +that i love it's + + + align:start position:0% +that i love it's +told by wangari matai who's a nobel + + align:start position:0% +told by wangari matai who's a nobel + + + align:start position:0% +told by wangari matai who's a nobel +peace prize winner + + align:start position:0% +peace prize winner + + + align:start position:0% +peace prize winner +for her environmental work she tells the + + align:start position:0% +for her environmental work she tells the + + + align:start position:0% +for her environmental work she tells the +story + + align:start position:0% +story + + + align:start position:0% +story +of a great big forest fire and how all + + align:start position:0% +of a great big forest fire and how all + + + align:start position:0% +of a great big forest fire and how all +of the animals + + align:start position:0% +of the animals + + + align:start position:0% +of the animals +are running out of the forest and + + align:start position:0% +are running out of the forest and + + + align:start position:0% +are running out of the forest and +they're standing next to it + + align:start position:0% +they're standing next to it + + + align:start position:0% +they're standing next to it +as it burns but one animal the + + align:start position:0% +as it burns but one animal the + + + align:start position:0% +as it burns but one animal the +hummingbird + + align:start position:0% +hummingbird + + + align:start position:0% +hummingbird +starts going to a nearby lake and + + align:start position:0% +starts going to a nearby lake and + + + align:start position:0% +starts going to a nearby lake and +carrying + + align:start position:0% +carrying + + + align:start position:0% +carrying +one drop of water at a time to douse the + + align:start position:0% +one drop of water at a time to douse the + + + align:start position:0% +one drop of water at a time to douse the +forest fire + + align:start position:0% +forest fire + + + align:start position:0% +forest fire +and all the other animals are asking + + align:start position:0% +and all the other animals are asking + + + align:start position:0% +and all the other animals are asking +what are you doing you're so small + + align:start position:0% +what are you doing you're so small + + + align:start position:0% +what are you doing you're so small +this fire is so big you can't possibly + + align:start position:0% +this fire is so big you can't possibly + + + align:start position:0% +this fire is so big you can't possibly +do anything + + align:start position:0% +do anything + + + align:start position:0% +do anything +about it the elephant is standing there + + align:start position:0% +about it the elephant is standing there + + + align:start position:0% +about it the elephant is standing there +with its big trunk + + align:start position:0% +with its big trunk + + + align:start position:0% +with its big trunk +all the other animals that are also much + + align:start position:0% +all the other animals that are also much + + + align:start position:0% +all the other animals that are also much +bigger just doing nothing + + align:start position:0% +bigger just doing nothing + + + align:start position:0% +bigger just doing nothing +the hummingbird keeps on going and then + + align:start position:0% +the hummingbird keeps on going and then + + + align:start position:0% +the hummingbird keeps on going and then +finally + + align:start position:0% +finally + + + align:start position:0% +finally +without missing a beat the hummingbird + + align:start position:0% +without missing a beat the hummingbird + + + align:start position:0% +without missing a beat the hummingbird +says + + align:start position:0% +says + + + align:start position:0% +says +i'm doing the best i can + + align:start position:0% +i'm doing the best i can + + + align:start position:0% +i'm doing the best i can +and when gary mattai says we should all + + align:start position:0% +and when gary mattai says we should all + + + align:start position:0% +and when gary mattai says we should all +be like hummingbirds + + align:start position:0% +be like hummingbirds + + + align:start position:0% +be like hummingbirds +we should all just do the best that we + + align:start position:0% +we should all just do the best that we + + + align:start position:0% +we should all just do the best that we +can and some days that's not + + align:start position:0% +can and some days that's not + + + align:start position:0% +can and some days that's not +very much at all and that's okay but we + + align:start position:0% +very much at all and that's okay but we + + + align:start position:0% +very much at all and that's okay but we +should all remember + + align:start position:0% +should all remember + + + align:start position:0% +should all remember +that we each can do something and that + + align:start position:0% +that we each can do something and that + + + align:start position:0% +that we each can do something and that +that matters + + align:start position:0% +that matters + + + align:start position:0% +that matters +and that that's enough in that moment + + align:start position:0% + + + + align:start position:0% + +in our individual work on climate change + + align:start position:0% +in our individual work on climate change + + + align:start position:0% +in our individual work on climate change +it's okay to take the approach of the + + align:start position:0% +it's okay to take the approach of the + + + align:start position:0% +it's okay to take the approach of the +hummingbird to make a difference + + align:start position:0% +hummingbird to make a difference + + + align:start position:0% +hummingbird to make a difference +if you're interested in becoming an + + align:start position:0% +if you're interested in becoming an + + + align:start position:0% +if you're interested in becoming an +earth dna ambassador or want to learn + + align:start position:0% +earth dna ambassador or want to learn + + + align:start position:0% +earth dna ambassador or want to learn +more about their training program and + + align:start position:0% +more about their training program and + + + align:start position:0% +more about their training program and +materials + + align:start position:0% +materials + + + align:start position:0% +materials +head to earthdna.org ambassadors + + align:start position:0% +head to earthdna.org ambassadors + + + align:start position:0% +head to earthdna.org ambassadors +you can also find the climate 101 + + align:start position:0% +you can also find the climate 101 + + + align:start position:0% +you can also find the climate 101 +presentation slides + + align:start position:0% +presentation slides + + + align:start position:0% +presentation slides +a video of brandon giving the + + align:start position:0% +a video of brandon giving the + + + align:start position:0% +a video of brandon giving the +presentation ambassador program + + align:start position:0% +presentation ambassador program + + + align:start position:0% +presentation ambassador program +application + + align:start position:0% +application + + + align:start position:0% +application +handouts and volunteer resources on our + + align:start position:0% +handouts and volunteer resources on our + + + align:start position:0% +handouts and volunteer resources on our +mit open courseware website + + align:start position:0% +mit open courseware website + + + align:start position:0% +mit open courseware website +and by the way did you know + + align:start position:0% +and by the way did you know + + + align:start position:0% +and by the way did you know +opencourseware is turning 20 + + align:start position:0% +opencourseware is turning 20 + + + align:start position:0% +opencourseware is turning 20 +it's taken a community to bring ocw to + + align:start position:0% +it's taken a community to bring ocw to + + + align:start position:0% +it's taken a community to bring ocw to +this moment + + align:start position:0% +this moment + + + align:start position:0% +this moment +and we want you to be a part of it and + + align:start position:0% +and we want you to be a part of it and + + + align:start position:0% +and we want you to be a part of it and +what comes next + + align:start position:0% +what comes next + + + align:start position:0% +what comes next +please join us for a virtual celebration + + align:start position:0% +please join us for a virtual celebration + + + align:start position:0% +please join us for a virtual celebration +of ocw's impact + + align:start position:0% +of ocw's impact + + + align:start position:0% +of ocw's impact +community and the future of open sharing + + align:start position:0% +community and the future of open sharing + + + align:start position:0% +community and the future of open sharing +on wednesday april 7th + + align:start position:0% +on wednesday april 7th + + + align:start position:0% +on wednesday april 7th +2021 at 12 pm eastern time you can + + align:start position:0% +2021 at 12 pm eastern time you can + + + align:start position:0% +2021 at 12 pm eastern time you can +register using the link in our show + + align:start position:0% +register using the link in our show + + + align:start position:0% +register using the link in our show +notes + + align:start position:0% +notes + + + align:start position:0% +notes +or just tune in live to ocw's youtube + + align:start position:0% +or just tune in live to ocw's youtube + + + align:start position:0% +or just tune in live to ocw's youtube +instagram or facebook pages + + align:start position:0% +instagram or facebook pages + + + align:start position:0% +instagram or facebook pages +thank you for making these first two + + align:start position:0% +thank you for making these first two + + + align:start position:0% +thank you for making these first two +decades possible and thanks so much for + + align:start position:0% +decades possible and thanks so much for + + + align:start position:0% +decades possible and thanks so much for +listening to the chalk radio podcast + + align:start position:0% +listening to the chalk radio podcast + + + align:start position:0% +listening to the chalk radio podcast +until i see you on april 7th signing off + + align:start position:0% +until i see you on april 7th signing off + + + align:start position:0% +until i see you on april 7th signing off +from cambridge massachusetts + + align:start position:0% +from cambridge massachusetts + + + align:start position:0% +from cambridge massachusetts +i'm sarah hansen from mit opencourseware + + align:start position:0% +i'm sarah hansen from mit opencourseware + + + align:start position:0% +i'm sarah hansen from mit opencourseware +mom passed the car \ No newline at end of file diff --git a/kEtov6pV_1Q.txt b/kEtov6pV_1Q.txt new file mode 100644 index 0000000000000000000000000000000000000000..3c2d625745d48d3d52d399b5ad49affc45e57209 --- /dev/null +++ b/kEtov6pV_1Q.txt @@ -0,0 +1,3371 @@ +align:start position:0% + +hello computational music analysts I'm + + align:start position:0% +hello computational music analysts I'm + + + align:start position:0% +hello computational music analysts I'm +going to talk a little bit today about + + align:start position:0% +going to talk a little bit today about + + + align:start position:0% +going to talk a little bit today about +some topics that are not in themselves + + align:start position:0% +some topics that are not in themselves + + + align:start position:0% +some topics that are not in themselves +essentially computational although + + align:start position:0% +essentially computational although + + + align:start position:0% +essentially computational although +having a computer helps but are really + + align:start position:0% +having a computer helps but are really + + + align:start position:0% +having a computer helps but are really +about the intersection of mathematical + + align:start position:0% +about the intersection of mathematical + + + align:start position:0% +about the intersection of mathematical +and quantitative thinking with music + + align:start position:0% +and quantitative thinking with music + + + align:start position:0% +and quantitative thinking with music +analysis music theory and musicology the + + align:start position:0% +analysis music theory and musicology the + + + align:start position:0% +analysis music theory and musicology the +study of music + + align:start position:0% +study of music + + + align:start position:0% +study of music +history and these are some of the things + + align:start position:0% +history and these are some of the things + + + align:start position:0% +history and these are some of the things +that I've done in my own research that I + + align:start position:0% +that I've done in my own research that I + + + align:start position:0% +that I've done in my own research that I +hope will make you think about some ways + + align:start position:0% +hope will make you think about some ways + + + align:start position:0% +hope will make you think about some ways +that data analysis can go beyond the + + align:start position:0% +that data analysis can go beyond the + + + align:start position:0% +that data analysis can go beyond the +score and tell us something more about + + align:start position:0% +score and tell us something more about + + + align:start position:0% +score and tell us something more about +the history of + + align:start position:0% +the history of + + + align:start position:0% +the history of +music what I'm not doing computational + + align:start position:0% +music what I'm not doing computational + + + align:start position:0% +music what I'm not doing computational +music analysis my other job is as a + + align:start position:0% +music analysis my other job is as a + + + align:start position:0% +music analysis my other job is as a +medieval music researcher and one of the + + align:start position:0% +medieval music researcher and one of the + + + align:start position:0% +medieval music researcher and one of the +certainties I was always taught um about + + align:start position:0% +certainties I was always taught um about + + + align:start position:0% +certainties I was always taught um about +Medieval music is that we've + + align:start position:0% +Medieval music is that we've + + + align:start position:0% +Medieval music is that we've +lost most of it we've lost so much of it + + align:start position:0% +lost most of it we've lost so much of it + + + align:start position:0% +lost most of it we've lost so much of it +and I mean it's it's just incredible how + + align:start position:0% +and I mean it's it's just incredible how + + + align:start position:0% +and I mean it's it's just incredible how +much we have in fact most people always + + align:start position:0% +much we have in fact most people always + + + align:start position:0% +much we have in fact most people always +said that um The Sur the music that + + align:start position:0% +said that um The Sur the music that + + + align:start position:0% +said that um The Sur the music that +survives is just the tip of the iceberg + + align:start position:0% +survives is just the tip of the iceberg + + + align:start position:0% +survives is just the tip of the iceberg +it was first said by a very important + + align:start position:0% +it was first said by a very important + + + align:start position:0% +it was first said by a very important +medieval his U musicologist Nino Perot + + align:start position:0% +medieval his U musicologist Nino Perot + + + align:start position:0% +medieval his U musicologist Nino Perot +uh but this term was picked up from on + + align:start position:0% +uh but this term was picked up from on + + + align:start position:0% +uh but this term was picked up from on +by dozens of other people and so um when + + align:start position:0% +by dozens of other people and so um when + + + align:start position:0% +by dozens of other people and so um when +we think about what's lost it could be + + align:start position:0% +we think about what's lost it could be + + + align:start position:0% +we think about what's lost it could be +number of manuscripts that's lost or it + + align:start position:0% +number of manuscripts that's lost or it + + + align:start position:0% +number of manuscripts that's lost or it +could be things that um were lost + + align:start position:0% +could be things that um were lost + + + align:start position:0% +could be things that um were lost +because they were never written down and + + align:start position:0% +because they were never written down and + + + align:start position:0% +because they were never written down and +we've forgotten them but if we want to + + align:start position:0% +we've forgotten them but if we want to + + + align:start position:0% +we've forgotten them but if we want to +think about even the things that were + + align:start position:0% +think about even the things that were + + + align:start position:0% +think about even the things that were +once written down on songs that were + + align:start position:0% +once written down on songs that were + + + align:start position:0% +once written down on songs that were +once written down the pieces that were + + align:start position:0% +once written down the pieces that were + + + align:start position:0% +once written down the pieces that were +once written down uh how many of them do + + align:start position:0% +once written down uh how many of them do + + + align:start position:0% +once written down uh how many of them do +no longer have any copy of at all um + + align:start position:0% +no longer have any copy of at all um + + + align:start position:0% +no longer have any copy of at all um +what is the tip of the iceberg uh is it + + align:start position:0% +what is the tip of the iceberg uh is it + + + align:start position:0% +what is the tip of the iceberg uh is it +90% that's what a lot of people say you + + align:start position:0% +90% that's what a lot of people say you + + + align:start position:0% +90% that's what a lot of people say you +know the visible part of the iceberg is + + align:start position:0% +know the visible part of the iceberg is + + + align:start position:0% +know the visible part of the iceberg is +is it 99% lost uh 99.9% lost or is one + + align:start position:0% +is it 99% lost uh 99.9% lost or is one + + + align:start position:0% +is it 99% lost uh 99.9% lost or is one +person said basically everything so I'll + + align:start position:0% +person said basically everything so I'll + + + align:start position:0% +person said basically everything so I'll +call that + + align:start position:0% + + + + align:start position:0% + +99.9999% my friend and former teacher + + align:start position:0% +99.9999% my friend and former teacher + + + align:start position:0% +99.9999% my friend and former teacher +Sean Gallagher once asked me hey would + + align:start position:0% +Sean Gallagher once asked me hey would + + + align:start position:0% +Sean Gallagher once asked me hey would +there be any way you know you're a math + + align:start position:0% +there be any way you know you're a math + + + align:start position:0% +there be any way you know you're a math +guy to prove this to show that it's true + + align:start position:0% +guy to prove this to show that it's true + + + align:start position:0% +guy to prove this to show that it's true +and you know I immediately said no you + + align:start position:0% +and you know I immediately said no you + + + align:start position:0% +and you know I immediately said no you +know there's no way we could do this + + align:start position:0% +know there's no way we could do this + + + align:start position:0% +know there's no way we could do this +then I thought a little bit more and + + align:start position:0% +then I thought a little bit more and + + + align:start position:0% +then I thought a little bit more and +realized there are people who look at um + + align:start position:0% +realized there are people who look at um + + + align:start position:0% +realized there are people who look at um +you know how things get lost and stuff I + + align:start position:0% +you know how things get lost and stuff I + + + align:start position:0% +you know how things get lost and stuff I +uh later on I found this great article + + align:start position:0% +uh later on I found this great article + + + align:start position:0% +uh later on I found this great article +on um what happens in peer-to-peer song + + align:start position:0% +on um what happens in peer-to-peer song + + + align:start position:0% +on um what happens in peer-to-peer song +sharing uh when you just start + + align:start position:0% +sharing uh when you just start + + + align:start position:0% +sharing uh when you just start +disconnecting lots of computers from the + + align:start position:0% +disconnecting lots of computers from the + + + align:start position:0% +disconnecting lots of computers from the +network as happened during the Crackdown + + align:start position:0% +network as happened during the Crackdown + + + align:start position:0% +network as happened during the Crackdown +on napers and things like that and um + + align:start position:0% +on napers and things like that and um + + + align:start position:0% +on napers and things like that and um +and they showed that as you go from if + + align:start position:0% +and they showed that as you go from if + + + align:start position:0% +and they showed that as you go from if +you have a 100,000 computers on a + + align:start position:0% +you have a 100,000 computers on a + + + align:start position:0% +you have a 100,000 computers on a +network you might have five million + + align:start position:0% +network you might have five million + + + align:start position:0% +network you might have five million +songs uh but if the network gets down to + + align:start position:0% +songs uh but if the network gets down to + + + align:start position:0% +songs uh but if the network gets down to +you know maybe 10,000 or 15,000 + + align:start position:0% +you know maybe 10,000 or 15,000 + + + align:start position:0% +you know maybe 10,000 or 15,000 +computers you only lose about half the + + align:start position:0% +computers you only lose about half the + + + align:start position:0% +computers you only lose about half the +song so that was kind of interesting to + + align:start position:0% +song so that was kind of interesting to + + + align:start position:0% +song so that was kind of interesting to +me that was a little bit + + align:start position:0% +me that was a little bit + + + align:start position:0% +me that was a little bit +counterintuitive that you could really + + align:start position:0% +counterintuitive that you could really + + + align:start position:0% +counterintuitive that you could really +lose a lot of nodes on a network and not + + align:start position:0% +lose a lot of nodes on a network and not + + + align:start position:0% +lose a lot of nodes on a network and not +lose a lot of the content there and I + + align:start position:0% +lose a lot of the content there and I + + + align:start position:0% +lose a lot of the content there and I +kind of thought well you know computers + + align:start position:0% +kind of thought well you know computers + + + align:start position:0% +kind of thought well you know computers +might be something like medieval + + align:start position:0% +might be something like medieval + + + align:start position:0% +might be something like medieval +manuscripts that we lose a bunch but + + align:start position:0% +manuscripts that we lose a bunch but + + + align:start position:0% +manuscripts that we lose a bunch but +maybe we still have the songs so I wrote + + align:start position:0% +maybe we still have the songs so I wrote + + + align:start position:0% +maybe we still have the songs so I wrote +two articles about this topic first um + + align:start position:0% +two articles about this topic first um + + + align:start position:0% +two articles about this topic first um +is what I'm really going to be talking + + align:start position:0% +is what I'm really going to be talking + + + align:start position:0% +is what I'm really going to be talking +about now uh it's an article called + + align:start position:0% +about now uh it's an article called + + + align:start position:0% +about now uh it's an article called +tipping the iceberg in a journal called + + align:start position:0% +tipping the iceberg in a journal called + + + align:start position:0% +tipping the iceberg in a journal called +mus discina and another it's a little + + align:start position:0% +mus discina and another it's a little + + + align:start position:0% +mus discina and another it's a little +bit harder to find uh it's called monks + + align:start position:0% +bit harder to find uh it's called monks + + + align:start position:0% +bit harder to find uh it's called monks +manuscripts and other peer-to-peer song + + align:start position:0% +manuscripts and other peer-to-peer song + + + align:start position:0% +manuscripts and other peer-to-peer song +sharing networks of the Middle Ages it's + + align:start position:0% +sharing networks of the Middle Ages it's + + + align:start position:0% +sharing networks of the Middle Ages it's +in a great uh book that the University + + align:start position:0% +in a great uh book that the University + + + align:start position:0% +in a great uh book that the University +of Pennsylvania uh helped publish called + + align:start position:0% +of Pennsylvania uh helped publish called + + + align:start position:0% +of Pennsylvania uh helped publish called +Kus scriptus Technologies of medieval + + align:start position:0% +Kus scriptus Technologies of medieval + + + align:start position:0% +Kus scriptus Technologies of medieval +song like the idea of Technology + + align:start position:0% +song like the idea of Technology + + + align:start position:0% +song like the idea of Technology +existing throughout history anyhow so + + align:start position:0% +existing throughout history anyhow so + + + align:start position:0% +existing throughout history anyhow so +one of the ways that we could do this is + + align:start position:0% +one of the ways that we could do this is + + + align:start position:0% +one of the ways that we could do this is +just you know look at all the records of + + align:start position:0% +just you know look at all the records of + + + align:start position:0% +just you know look at all the records of +missing pieces and see how many of them + + align:start position:0% +missing pieces and see how many of them + + + align:start position:0% +missing pieces and see how many of them +we have and that's kind of sarcastic but + + align:start position:0% +we have and that's kind of sarcastic but + + + align:start position:0% +we have and that's kind of sarcastic but +there are things uh that exist in the + + align:start position:0% +there are things uh that exist in the + + + align:start position:0% +there are things uh that exist in the +world like this um there's a + + align:start position:0% +world like this um there's a + + + align:start position:0% +world like this um there's a +manuscript it's actually only uh I think + + align:start position:0% +manuscript it's actually only uh I think + + + align:start position:0% +manuscript it's actually only uh I think +two or four pages survive now um that + + align:start position:0% +two or four pages survive now um that + + + align:start position:0% +two or four pages survive now um that +was owned by The Duchess of troil so + + align:start position:0% +was owned by The Duchess of troil so + + + align:start position:0% +was owned by The Duchess of troil so +it's often called the tro uh manuscript + + align:start position:0% +it's often called the tro uh manuscript + + + align:start position:0% +it's often called the tro uh manuscript +it's in um it's in the National Library + + align:start position:0% +it's in um it's in the National Library + + + align:start position:0% +it's in um it's in the National Library +of Paris now and if you look at this + + align:start position:0% +of Paris now and if you look at this + + + align:start position:0% +of Paris now and if you look at this +manuscript uh what what we only have a + + align:start position:0% +manuscript uh what what we only have a + + + align:start position:0% +manuscript uh what what we only have a +couple pages of it but we have the + + align:start position:0% +couple pages of it but we have the + + + align:start position:0% +couple pages of it but we have the +entire index the table of contents that + + align:start position:0% +entire index the table of contents that + + + align:start position:0% +entire index the table of contents that +tells you uh what the names of the + + align:start position:0% +tells you uh what the names of the + + + align:start position:0% +tells you uh what the names of the +pieces are and what page they would have + + align:start position:0% +pieces are and what page they would have + + + align:start position:0% +pieces are and what page they would have +been on in the original manuscript so we + + align:start position:0% +been on in the original manuscript so we + + + align:start position:0% +been on in the original manuscript so we +can look at well we don't have this + + align:start position:0% +can look at well we don't have this + + + align:start position:0% +can look at well we don't have this +manuscript but how many of these pieces + + align:start position:0% +manuscript but how many of these pieces + + + align:start position:0% +manuscript but how many of these pieces +do we have we have we lost so we can see + + align:start position:0% +do we have we have we lost so we can see + + + align:start position:0% +do we have we have we lost so we can see +that uh I've marked here these are all + + align:start position:0% +that uh I've marked here these are all + + + align:start position:0% +that uh I've marked here these are all +the pieces that we're pretty sure we + + align:start position:0% +the pieces that we're pretty sure we + + + align:start position:0% +the pieces that we're pretty sure we +don't have copies of and um here's all + + align:start position:0% +don't have copies of and um here's all + + + align:start position:0% +don't have copies of and um here's all +the pieces that we're pretty sure we do + + align:start position:0% +the pieces that we're pretty sure we do + + + align:start position:0% +the pieces that we're pretty sure we do +have + + align:start position:0% +have + + + align:start position:0% +have +copies there's some pieces that we can't + + align:start position:0% +copies there's some pieces that we can't + + + align:start position:0% +copies there's some pieces that we can't +really be sure they're um parts + + align:start position:0% +really be sure they're um parts + + + align:start position:0% +really be sure they're um parts +of Medieval music Traditions like the + + align:start position:0% +of Medieval music Traditions like the + + + align:start position:0% +of Medieval music Traditions like the +mass that have these somewhat generic + + align:start position:0% +mass that have these somewhat generic + + + align:start position:0% +mass that have these somewhat generic +names like k or something kind of like + + align:start position:0% +names like k or something kind of like + + + align:start position:0% +names like k or something kind of like +if we saw oh we lost Symphony well you + + align:start position:0% +if we saw oh we lost Symphony well you + + + align:start position:0% +if we saw oh we lost Symphony well you +know who who Symphony things like that + + align:start position:0% +know who who Symphony things like that + + + align:start position:0% +know who who Symphony things like that +um so when we overlay these two together + + align:start position:0% +um so when we overlay these two together + + + align:start position:0% +um so when we overlay these two together +we see that actually those that survive + + align:start position:0% +we see that actually those that survive + + + align:start position:0% +we see that actually those that survive +really outrank those that don't so so in + + align:start position:0% +really outrank those that don't so so in + + + align:start position:0% +really outrank those that don't so so in +this particular index we have 114 + + align:start position:0% +this particular index we have 114 + + + align:start position:0% +this particular index we have 114 +compositions that um of of which 109 are + + align:start position:0% +compositions that um of of which 109 are + + + align:start position:0% +compositions that um of of which 109 are +identifiable and 68% of them seem to + + align:start position:0% +identifiable and 68% of them seem to + + + align:start position:0% +identifiable and 68% of them seem to +survive or another thing that I looked + + align:start position:0% +survive or another thing that I looked + + + align:start position:0% +survive or another thing that I looked +at was this collection of um sonnets by + + align:start position:0% +at was this collection of um sonnets by + + + align:start position:0% +at was this collection of um sonnets by +a kind of cool but second tier Italian + + align:start position:0% +a kind of cool but second tier Italian + + + align:start position:0% +a kind of cool but second tier Italian +poet named pranii and one of the things + + align:start position:0% +poet named pranii and one of the things + + + align:start position:0% +poet named pranii and one of the things +that um that makes a lot of people think + + align:start position:0% +that um that makes a lot of people think + + + align:start position:0% +that um that makes a lot of people think +he's second tier is is he throws in a + + align:start position:0% +he's second tier is is he throws in a + + + align:start position:0% +he's second tier is is he throws in a +lot of his songs just uh lists of things + + align:start position:0% +lot of his songs just uh lists of things + + + align:start position:0% +lot of his songs just uh lists of things +lists of all the food they eat at lists + + align:start position:0% +lists of all the food they eat at lists + + + align:start position:0% +lists of all the food they eat at lists +of all the dances they they danced that + + align:start position:0% +of all the dances they they danced that + + + align:start position:0% +of all the dances they they danced that +day and in this particular case a list + + align:start position:0% +day and in this particular case a list + + + align:start position:0% +day and in this particular case a list +of all the songs that were sung Begins + + align:start position:0% +of all the songs that were sung Begins + + + align:start position:0% +of all the songs that were sung Begins +the top Bo kind of kind of nice for + + align:start position:0% +the top Bo kind of kind of nice for + + + align:start position:0% +the top Bo kind of kind of nice for +where we're about to be in the year uh + + align:start position:0% +where we're about to be in the year uh + + + align:start position:0% +where we're about to be in the year uh +with the violin Viola something they + + align:start position:0% +with the violin Viola something they + + + align:start position:0% +with the violin Viola something they +made all the May songs like Ros Ki my + + align:start position:0% +made all the May songs like Ros Ki my + + + align:start position:0% +made all the May songs like Ros Ki my +the rose that never changes it + + align:start position:0% + + + + align:start position:0% + +colors etc etc we can basically figure + + align:start position:0% +colors etc etc we can basically figure + + + align:start position:0% +colors etc etc we can basically figure +out which ones of these um things are + + align:start position:0% +out which ones of these um things are + + + align:start position:0% +out which ones of these um things are +titles of songs and then we can see how + + align:start position:0% +titles of songs and then we can see how + + + align:start position:0% +titles of songs and then we can see how +many of them we know so + + align:start position:0% +many of them we know so + + + align:start position:0% +many of them we know so +Ros is a song that survives so is so + + align:start position:0% + + + + align:start position:0% + +is but some of them like uh toward the + + align:start position:0% + + + + align:start position:0% + +bottom we don't know that song so so we + + align:start position:0% +bottom we don't know that song so so we + + + align:start position:0% +bottom we don't know that song so so we +can look over and again we can see how + + align:start position:0% +can look over and again we can see how + + + align:start position:0% +can look over and again we can see how +many of them survive how many of them + + align:start position:0% +many of them survive how many of them + + + align:start position:0% +many of them survive how many of them +don't survive and then these other four + + align:start position:0% +don't survive and then these other four + + + align:start position:0% +don't survive and then these other four +um where we can argue about um that + + align:start position:0% +um where we can argue about um that + + + align:start position:0% +um where we can argue about um that +there's songs with similar titles are + + align:start position:0% +there's songs with similar titles are + + + align:start position:0% +there's songs with similar titles are +they just being misquoted or um are they + + align:start position:0% +they just being misquoted or um are they + + + align:start position:0% +they just being misquoted or um are they +same or is this really a song things + + align:start position:0% +same or is this really a song things + + + align:start position:0% +same or is this really a song things +like that so uh it's these are the two + + align:start position:0% +like that so uh it's these are the two + + + align:start position:0% +like that so uh it's these are the two +proportions that it could be so + + align:start position:0% +proportions that it could be so + + + align:start position:0% +proportions that it could be so +depending on what we look at there's + + align:start position:0% +depending on what we look at there's + + + align:start position:0% +depending on what we look at there's +somewhere between 16 and 17 compositions + + align:start position:0% +somewhere between 16 and 17 compositions + + + align:start position:0% +somewhere between 16 and 17 compositions +and three to to seven of them are lost + + align:start position:0% +and three to to seven of them are lost + + + align:start position:0% +and three to to seven of them are lost +10 to 12 survive um so that's about 59 + + align:start position:0% +10 to 12 survive um so that's about 59 + + + align:start position:0% +10 to 12 survive um so that's about 59 +to 75% of the songs here + + align:start position:0% +to 75% of the songs here + + + align:start position:0% +to 75% of the songs here +survive if we look at all of the sonnets + + align:start position:0% +survive if we look at all of the sonnets + + + align:start position:0% +survive if we look at all of the sonnets +in this collection by protani there's 59 + + align:start position:0% +in this collection by protani there's 59 + + + align:start position:0% +in this collection by protani there's 59 +identifiable compositions and 40 of them + + align:start position:0% +identifiable compositions and 40 of them + + + align:start position:0% +identifiable compositions and 40 of them +surviv so that's + + align:start position:0% +surviv so that's + + + align:start position:0% +surviv so that's +71% so here's two pieces of evidence um + + align:start position:0% +71% so here's two pieces of evidence um + + + align:start position:0% +71% so here's two pieces of evidence um +both from textual sources to try to see + + align:start position:0% +both from textual sources to try to see + + + align:start position:0% +both from textual sources to try to see +um how how much survives or how much + + align:start position:0% +um how how much survives or how much + + + align:start position:0% +um how how much survives or how much +doesn't but can can we do + + align:start position:0% +doesn't but can can we do + + + align:start position:0% +doesn't but can can we do +better one of the things I thought of + + align:start position:0% +better one of the things I thought of + + + align:start position:0% +better one of the things I thought of +was that there are people who spend a + + align:start position:0% +was that there are people who spend a + + + align:start position:0% +was that there are people who spend a +lot of time trying to count things that + + align:start position:0% +lot of time trying to count things that + + + align:start position:0% +lot of time trying to count things that +are difficult to count because you can't + + align:start position:0% +are difficult to count because you can't + + + align:start position:0% +are difficult to count because you can't +sort of capture them all uh they are the + + align:start position:0% +sort of capture them all uh they are the + + + align:start position:0% +sort of capture them all uh they are the +animal population + + align:start position:0% +animal population + + + align:start position:0% +animal population +biologists they are people who go out + + align:start position:0% +biologists they are people who go out + + + align:start position:0% +biologists they are people who go out +and um they can't capture every deer in + + align:start position:0% +and um they can't capture every deer in + + + align:start position:0% +and um they can't capture every deer in +a forest so what do they do they um they + + align:start position:0% +a forest so what do they do they um they + + + align:start position:0% +a forest so what do they do they um they +might go out here's one way that they do + + align:start position:0% +might go out here's one way that they do + + + align:start position:0% +might go out here's one way that they do +it they may go out at a certain point + + align:start position:0% +it they may go out at a certain point + + + align:start position:0% +it they may go out at a certain point +and go and um capture you know all the + + align:start position:0% +and go and um capture you know all the + + + align:start position:0% +and go and um capture you know all the +deer they can capture in a couple days + + align:start position:0% +deer they can capture in a couple days + + + align:start position:0% +deer they can capture in a couple days +um you know maybe it's let's say it's 10 + + align:start position:0% +um you know maybe it's let's say it's 10 + + + align:start position:0% +um you know maybe it's let's say it's 10 +10 deer and they go and they tag the + + align:start position:0% +10 deer and they go and they tag the + + + align:start position:0% +10 deer and they go and they tag the +deer in some way or something somehow + + align:start position:0% +deer in some way or something somehow + + + align:start position:0% +deer in some way or something somehow +somehow they you know so they can + + align:start position:0% +somehow they you know so they can + + + align:start position:0% +somehow they you know so they can +recognize the same deer again then maybe + + align:start position:0% +recognize the same deer again then maybe + + + align:start position:0% +recognize the same deer again then maybe +you know they let a month go by or + + align:start position:0% +you know they let a month go by or + + + align:start position:0% +you know they let a month go by or +something not too long but more enough + + align:start position:0% +something not too long but more enough + + + align:start position:0% +something not too long but more enough +time that animals can move around and + + align:start position:0% +time that animals can move around and + + + align:start position:0% +time that animals can move around and +stuff and then they go out and they + + align:start position:0% +stuff and then they go out and they + + + align:start position:0% +stuff and then they go out and they +capture deer for a day again and let's + + align:start position:0% +capture deer for a day again and let's + + + align:start position:0% +capture deer for a day again and let's +say you know they capture 10 deer again + + align:start position:0% +say you know they capture 10 deer again + + + align:start position:0% +say you know they capture 10 deer again +uh the point is the second time they do + + align:start position:0% +uh the point is the second time they do + + + align:start position:0% +uh the point is the second time they do +a capture this called capture recapture + + align:start position:0% +a capture this called capture recapture + + + align:start position:0% +a capture this called capture recapture +methods the second time they do it they + + align:start position:0% +methods the second time they do it they + + + align:start position:0% +methods the second time they do it they +look to see how many of the deer that we + + align:start position:0% +look to see how many of the deer that we + + + align:start position:0% +look to see how many of the deer that we +captured the second time did we also + + align:start position:0% +captured the second time did we also + + + align:start position:0% +captured the second time did we also +capture the first time if you think + + align:start position:0% +capture the first time if you think + + + align:start position:0% +capture the first time if you think +about it if you go into a forest and you + + align:start position:0% +about it if you go into a forest and you + + + align:start position:0% +about it if you go into a forest and you +know you you walked around pretty + + align:start position:0% +know you you walked around pretty + + + align:start position:0% +know you you walked around pretty +randomly or something and you all of the + + align:start position:0% +randomly or something and you all of the + + + align:start position:0% +randomly or something and you all of the +deer or nine out of the 10 deer that you + + align:start position:0% +deer or nine out of the 10 deer that you + + + align:start position:0% +deer or nine out of the 10 deer that you +captur the first time you see the same + + align:start position:0% +captur the first time you see the same + + + align:start position:0% +captur the first time you see the same +ones the second time you might think wow + + align:start position:0% +ones the second time you might think wow + + + align:start position:0% +ones the second time you might think wow +we've seen almost all the deer in the + + align:start position:0% + + + + align:start position:0% + +forest on the other hand let's say you + + align:start position:0% +forest on the other hand let's say you + + + align:start position:0% +forest on the other hand let's say you +captured 10 deer and none of them that + + align:start position:0% +captured 10 deer and none of them that + + + align:start position:0% +captured 10 deer and none of them that +you captured the second time had the tax + + align:start position:0% +you captured the second time had the tax + + + align:start position:0% +you captured the second time had the tax +you'd be like wow okay I know I've seen + + align:start position:0% +you'd be like wow okay I know I've seen + + + align:start position:0% +you'd be like wow okay I know I've seen +20 deer here but law of averages suggest + + align:start position:0% +20 deer here but law of averages suggest + + + align:start position:0% +20 deer here but law of averages suggest +there's a lot more than 20 deer and in + + align:start position:0% +there's a lot more than 20 deer and in + + + align:start position:0% +there's a lot more than 20 deer and in +fact there's um there's formulas that + + align:start position:0% +fact there's um there's formulas that + + + align:start position:0% +fact there's um there's formulas that +can you can uh that people do with this + + align:start position:0% +can you can uh that people do with this + + + align:start position:0% +can you can uh that people do with this +type of thing + + align:start position:0% +type of thing + + + align:start position:0% +type of thing +um so I tried to figure out you know + + align:start position:0% +um so I tried to figure out you know + + + align:start position:0% +um so I tried to figure out you know +what would be the equivalent in in music + + align:start position:0% +what would be the equivalent in in music + + + align:start position:0% +what would be the equivalent in in music +and so um I started to think you know uh + + align:start position:0% +and so um I started to think you know uh + + + align:start position:0% +and so um I started to think you know uh +let's go and look at some equations we + + align:start position:0% +let's go and look at some equations we + + + align:start position:0% +let's go and look at some equations we +might make uh if we had the number of + + align:start position:0% +might make uh if we had the number of + + + align:start position:0% +might make uh if we had the number of +pieces if we knew the number of pieces + + align:start position:0% +pieces if we knew the number of pieces + + + align:start position:0% +pieces if we knew the number of pieces +that originally existed and we + + align:start position:0% +that originally existed and we + + + align:start position:0% +that originally existed and we +multiplied by the probability that any + + align:start position:0% +multiplied by the probability that any + + + align:start position:0% +multiplied by the probability that any +given piece would be + + align:start position:0% +given piece would be + + + align:start position:0% +given piece would be +missing we would know the total number + + align:start position:0% +missing we would know the total number + + + align:start position:0% +missing we would know the total number +of missing + + align:start position:0% +of missing + + + align:start position:0% +of missing +pieces that's + + align:start position:0% +pieces that's + + + align:start position:0% +pieces that's +fantastic that is a very hard uh + + align:start position:0% +fantastic that is a very hard uh + + + align:start position:0% +fantastic that is a very hard uh +equation it's very hard to argue against + + align:start position:0% +equation it's very hard to argue against + + + align:start position:0% +equation it's very hard to argue against +but it's completely useless right we + + align:start position:0% +but it's completely useless right we + + + align:start position:0% +but it's completely useless right we +don't know the number of pieces + + align:start position:0% +don't know the number of pieces + + + align:start position:0% +don't know the number of pieces +originally we don't know the probability + + align:start position:0% +originally we don't know the probability + + + align:start position:0% +originally we don't know the probability +that any given piece would be missing + + align:start position:0% +that any given piece would be missing + + + align:start position:0% +that any given piece would be missing +and therefore we don't know how many + + align:start position:0% +and therefore we don't know how many + + + align:start position:0% +and therefore we don't know how many +missing pieces are so one equation three + + align:start position:0% +missing pieces are so one equation three + + + align:start position:0% +missing pieces are so one equation three +unknowns we don't know any of + + align:start position:0% +unknowns we don't know any of + + + align:start position:0% +unknowns we don't know any of +them + + align:start position:0% +them + + + align:start position:0% +them +but we can think through some of the + + align:start position:0% +but we can think through some of the + + + align:start position:0% +but we can think through some of the +things here um I'm going to go through a + + align:start position:0% +things here um I'm going to go through a + + + align:start position:0% +things here um I'm going to go through a +quicker version of this but I have + + align:start position:0% +quicker version of this but I have + + + align:start position:0% +quicker version of this but I have +elsewhere well I have in my article um a + + align:start position:0% +elsewhere well I have in my article um a + + + align:start position:0% +elsewhere well I have in my article um a +little bit deeper version that talks + + align:start position:0% +little bit deeper version that talks + + + align:start position:0% +little bit deeper version that talks +about all the UN um the assumptions that + + align:start position:0% +about all the UN um the assumptions that + + + align:start position:0% +about all the UN um the assumptions that +could be in play but let's start with um + + align:start position:0% +could be in play but let's start with um + + + align:start position:0% +could be in play but let's start with um +how can we figure F out the probability + + align:start position:0% +how can we figure F out the probability + + + align:start position:0% +how can we figure F out the probability +that we're missing a given piece well + + align:start position:0% +that we're missing a given piece well + + + align:start position:0% +that we're missing a given piece well +here's one model and it's it's kind of a + + align:start position:0% +here's one model and it's it's kind of a + + + align:start position:0% +here's one model and it's it's kind of a +um it's kind of a bad assumption maybe + + align:start position:0% +um it's kind of a bad assumption maybe + + + align:start position:0% +um it's kind of a bad assumption maybe +to start with but here's one model uh + + align:start position:0% +to start with but here's one model uh + + + align:start position:0% +to start with but here's one model uh +what if there's just medieval scribes + + align:start position:0% +what if there's just medieval scribes + + + align:start position:0% +what if there's just medieval scribes +had baskets of pieces you just all the + + align:start position:0% +had baskets of pieces you just all the + + + align:start position:0% +had baskets of pieces you just all the +pieces they knew them all their head + + align:start position:0% +pieces they knew them all their head + + + align:start position:0% +pieces they knew them all their head +there something like that and they kind + + align:start position:0% +there something like that and they kind + + + align:start position:0% +there something like that and they kind +of randomly chose ones that they were + + align:start position:0% +of randomly chose ones that they were + + + align:start position:0% +of randomly chose ones that they were +going to write down well then the + + align:start position:0% +going to write down well then the + + + align:start position:0% +going to write down well then the +probability that a given piece would be + + align:start position:0% +probability that a given piece would be + + + align:start position:0% +probability that a given piece would be +in a particular manuscript is + + align:start position:0% +in a particular manuscript is + + + align:start position:0% +in a particular manuscript is +approximately um the proportion of all + + align:start position:0% +approximately um the proportion of all + + + align:start position:0% +approximately um the proportion of all +of the pieces in the manuscript there's + + align:start position:0% +of the pieces in the manuscript there's + + + align:start position:0% +of the pieces in the manuscript there's +if R sub I is the number of pieces in + + align:start position:0% +if R sub I is the number of pieces in + + + align:start position:0% +if R sub I is the number of pieces in +the manuscript and N is the total of + + align:start position:0% +the manuscript and N is the total of + + + align:start position:0% +the manuscript and N is the total of +pieces originally copied then we would + + align:start position:0% +pieces originally copied then we would + + + align:start position:0% +pieces originally copied then we would +know the probability that a piece would + + align:start position:0% +know the probability that a piece would + + + align:start position:0% +know the probability that a piece would +be in a given manuscript or song book + + align:start position:0% +be in a given manuscript or song book + + + align:start position:0% +be in a given manuscript or song book +it's not exactly that number because you + + align:start position:0% +it's not exactly that number because you + + + align:start position:0% +it's not exactly that number because you +don't do duplication but but it's pretty + + align:start position:0% +don't do duplication but but it's pretty + + + align:start position:0% +don't do duplication but but it's pretty +close um uh it's actually the people + + align:start position:0% +close um uh it's actually the people + + + align:start position:0% +close um uh it's actually the people +have argued against me that you know + + align:start position:0% +have argued against me that you know + + + align:start position:0% +have argued against me that you know +like well you have to correct for that + + align:start position:0% +like well you have to correct for that + + + align:start position:0% +like well you have to correct for that +error but you only have to correct for + + align:start position:0% +error but you only have to correct for + + + align:start position:0% +error but you only have to correct for +the probability of duplication if um if + + align:start position:0% +the probability of duplication if um if + + + align:start position:0% +the probability of duplication if um if +the number piece in that manuscript is + + align:start position:0% +the number piece in that manuscript is + + + align:start position:0% +the number piece in that manuscript is +very is close uh some major uh + + align:start position:0% +very is close uh some major uh + + + align:start position:0% +very is close uh some major uh +percentage of the total number pieces + + align:start position:0% +percentage of the total number pieces + + + align:start position:0% +percentage of the total number pieces +originally copied so um that's already + + align:start position:0% +originally copied so um that's already + + + align:start position:0% +originally copied so um that's already +kind of getting anyhow so this is the + + align:start position:0% +kind of getting anyhow so this is the + + + align:start position:0% +kind of getting anyhow so this is the +probability that given piece would be in + + align:start position:0% +probability that given piece would be in + + + align:start position:0% +probability that given piece would be in +the given manuscript from here we can + + align:start position:0% +the given manuscript from here we can + + + align:start position:0% +the given manuscript from here we can +work out what's the probability the + + align:start position:0% +work out what's the probability the + + + align:start position:0% +work out what's the probability the +piece is not in a given manuscript and + + align:start position:0% +piece is not in a given manuscript and + + + align:start position:0% +piece is not in a given manuscript and +we just subtract that from one great so + + align:start position:0% +we just subtract that from one great so + + + align:start position:0% +we just subtract that from one great so +so that's that's pretty good now let's + + align:start position:0% +so that's that's pretty good now let's + + + align:start position:0% +so that's that's pretty good now let's +say you have two independent manuscripts + + align:start position:0% +say you have two independent manuscripts + + + align:start position:0% +say you have two independent manuscripts +they're being copied in different places + + align:start position:0% +they're being copied in different places + + + align:start position:0% +they're being copied in different places +you know different people whatever + + align:start position:0% +you know different people whatever + + + align:start position:0% +you know different people whatever +something like that what would be the + + align:start position:0% +something like that what would be the + + + align:start position:0% +something like that what would be the +probability that the piece would not be + + align:start position:0% +probability that the piece would not be + + + align:start position:0% +probability that the piece would not be +in any of these two manuscripts and so + + align:start position:0% +in any of these two manuscripts and so + + + align:start position:0% +in any of these two manuscripts and so +you just multiply the probability that + + align:start position:0% +you just multiply the probability that + + + align:start position:0% +you just multiply the probability that +it wouldn't be in one + + align:start position:0% +it wouldn't be in one + + + align:start position:0% +it wouldn't be in one +manuscript and not in the other and so R + + align:start position:0% +manuscript and not in the other and so R + + + align:start position:0% +manuscript and not in the other and so R +sub one and R sub2 they're going to + + align:start position:0% +sub one and R sub2 they're going to + + + align:start position:0% +sub one and R sub2 they're going to +depend on how many pieces are in the + + align:start position:0% +depend on how many pieces are in the + + + align:start position:0% +depend on how many pieces are in the +manuscript but this would be the + + align:start position:0% +manuscript but this would be the + + + align:start position:0% +manuscript but this would be the +probability that some piece existing or + + align:start position:0% +probability that some piece existing or + + + align:start position:0% +probability that some piece existing or +not would be in would not be in any of + + align:start position:0% +not would be in would not be in any of + + + align:start position:0% +not would be in would not be in any of +two + + align:start position:0% +two + + + align:start position:0% +two +manuscripts so there's about 85 + + align:start position:0% +manuscripts so there's about 85 + + + align:start position:0% +manuscripts so there's about 85 +surviving medieval manuscripts in the + + align:start position:0% +surviving medieval manuscripts in the + + + align:start position:0% +surviving medieval manuscripts in the +period I'm most interested in um so of + + align:start position:0% +period I'm most interested in um so of + + + align:start position:0% +period I'm most interested in um so of +Italy from 1370 to + + align:start position:0% +Italy from 1370 to + + + align:start position:0% +Italy from 1370 to +1420 just after the black death and um + + align:start position:0% +1420 just after the black death and um + + + align:start position:0% +1420 just after the black death and um +during the time of the great papal + + align:start position:0% +during the time of the great papal + + + align:start position:0% +during the time of the great papal +Schism so there's about 85 of these + + align:start position:0% +Schism so there's about 85 of these + + + align:start position:0% +Schism so there's about 85 of these +manuscripts so what's the probability + + align:start position:0% +manuscripts so what's the probability + + + align:start position:0% +manuscripts so what's the probability +that any given piece would not be in any + + align:start position:0% +that any given piece would not be in any + + + align:start position:0% +that any given piece would not be in any +of the 85 surviving + + align:start position:0% +of the 85 surviving + + + align:start position:0% +of the 85 surviving +manuscripts and it looks something like + + align:start position:0% +manuscripts and it looks something like + + + align:start position:0% +manuscripts and it looks something like +this + + align:start position:0% + + + + align:start position:0% + +um + + align:start position:0% +um + + + align:start position:0% +um +so this is something you know that's + + align:start position:0% +so this is something you know that's + + + align:start position:0% +so this is something you know that's +it's a it's a big long um number but you + + align:start position:0% +it's a it's a big long um number but you + + + align:start position:0% +it's a it's a big long um number but you +can see that right at the very end this + + align:start position:0% +can see that right at the very end this + + + align:start position:0% +can see that right at the very end this +whatever this works out to is the equal + + align:start position:0% +whatever this works out to is the equal + + + align:start position:0% +whatever this works out to is the equal +to the probability that a piece would be + + align:start position:0% +to the probability that a piece would be + + + align:start position:0% +to the probability that a piece would be +missing because if a piece is not in any + + align:start position:0% +missing because if a piece is not in any + + + align:start position:0% +missing because if a piece is not in any +of the surviving manuscripts then it's + + align:start position:0% +of the surviving manuscripts then it's + + + align:start position:0% +of the surviving manuscripts then it's +missing to us today so this is kind of + + align:start position:0% +missing to us today so this is kind of + + + align:start position:0% +missing to us today so this is kind of +great we know all these are numbers + + align:start position:0% +great we know all these are numbers + + + align:start position:0% +great we know all these are numbers +because they're simply the number of + + align:start position:0% +because they're simply the number of + + + align:start position:0% +because they're simply the number of +pieces in a manuscript today uh not in + + align:start position:0% +pieces in a manuscript today uh not in + + + align:start position:0% +pieces in a manuscript today uh not in +originally say so we can take this and + + align:start position:0% +originally say so we can take this and + + + align:start position:0% +originally say so we can take this and +we can go back to our original equation + + align:start position:0% +we can go back to our original equation + + + align:start position:0% +we can go back to our original equation +with three + + align:start position:0% +with three + + + align:start position:0% +with three +unknowns and um substitute it into for + + align:start position:0% +unknowns and um substitute it into for + + + align:start position:0% +unknowns and um substitute it into for +that P of M place so we can see that now + + align:start position:0% +that P of M place so we can see that now + + + align:start position:0% +that P of M place so we can see that now +we have one equation and two unknowns um + + align:start position:0% +we have one equation and two unknowns um + + + align:start position:0% +we have one equation and two unknowns um +it's still a pretty honky equation but + + align:start position:0% +it's still a pretty honky equation but + + + align:start position:0% +it's still a pretty honky equation but +uh well that's good one equation two + + align:start position:0% +uh well that's good one equation two + + + align:start position:0% +uh well that's good one equation two +unknowns still two many unknowns right + + align:start position:0% +unknowns still two many unknowns right + + + align:start position:0% +unknowns still two many unknowns right +we need two equations at least if we're + + align:start position:0% +we need two equations at least if we're + + + align:start position:0% +we need two equations at least if we're +going to do two unknowns but we can look + + align:start position:0% +going to do two unknowns but we can look + + + align:start position:0% +going to do two unknowns but we can look +at this last answer this m what are the + + align:start position:0% +at this last answer this m what are the + + + align:start position:0% +at this last answer this m what are the +total number of missing pieces well the + + align:start position:0% +total number of missing pieces well the + + + align:start position:0% +total number of missing pieces well the +total number of missing pieces is just + + align:start position:0% +total number of missing pieces is just + + + align:start position:0% +total number of missing pieces is just +the number of pieces that originally + + align:start position:0% +the number of pieces that originally + + + align:start position:0% +the number of pieces that originally +existed which we don't know minus the + + align:start position:0% +existed which we don't know minus the + + + align:start position:0% +existed which we don't know minus the +number of pieces that survive which we + + align:start position:0% +number of pieces that survive which we + + + align:start position:0% +number of pieces that survive which we +do know if we have a pretty good catalog + + align:start position:0% +do know if we have a pretty good catalog + + + align:start position:0% +do know if we have a pretty good catalog +of everything that survives today then + + align:start position:0% +of everything that survives today then + + + align:start position:0% +of everything that survives today then +we can figure that out so now we go back + + align:start position:0% +we can figure that out so now we go back + + + align:start position:0% +we can figure that out so now we go back +and we see that we have actually just + + align:start position:0% +and we see that we have actually just + + + align:start position:0% +and we see that we have actually just +one equation and one unknown uh it's a + + align:start position:0% +one equation and one unknown uh it's a + + + align:start position:0% +one equation and one unknown uh it's a +pretty big equation um in fact a lot of + + align:start position:0% +pretty big equation um in fact a lot of + + + align:start position:0% +pretty big equation um in fact a lot of +the literature that I was reading from + + align:start position:0% +the literature that I was reading from + + + align:start position:0% +the literature that I was reading from +the 60s and 70s 80s was about okay you + + align:start position:0% +the 60s and 70s 80s was about okay you + + + align:start position:0% +the 60s and 70s 80s was about okay you +can't possibly solve an equation you of + + align:start position:0% +can't possibly solve an equation you of + + + align:start position:0% +can't possibly solve an equation you of +this dimensionality uh exactly so here's + + align:start position:0% +this dimensionality uh exactly so here's + + + align:start position:0% +this dimensionality uh exactly so here's +all the sophisticated math that we can + + align:start position:0% +all the sophisticated math that we can + + + align:start position:0% +all the sophisticated math that we can +do to + + align:start position:0% +do to + + + align:start position:0% +do to +um to try to um you to try to + + align:start position:0% +um to try to um you to try to + + + align:start position:0% +um to try to um you to try to +approximate it but in fact nowadays it's + + align:start position:0% +approximate it but in fact nowadays it's + + + align:start position:0% +approximate it but in fact nowadays it's +it's pretty simple what we can do is we + + align:start position:0% +it's pretty simple what we can do is we + + + align:start position:0% +it's pretty simple what we can do is we +can try different numbers for n the + + align:start position:0% +can try different numbers for n the + + + align:start position:0% +can try different numbers for n the +number of original pieces starting from + + align:start position:0% +number of original pieces starting from + + + align:start position:0% +number of original pieces starting from +you know one more than the numbers + + align:start position:0% +you know one more than the numbers + + + align:start position:0% +you know one more than the numbers +fiving pieces or something try all these + + align:start position:0% +fiving pieces or something try all these + + + align:start position:0% +fiving pieces or something try all these +numbers into here until the left side + + align:start position:0% +numbers into here until the left side + + + align:start position:0% +numbers into here until the left side +and the right side approximately Balan + + align:start position:0% +and the right side approximately Balan + + + align:start position:0% +and the right side approximately Balan +and we can do that with computers so uh + + align:start position:0% +and we can do that with computers so uh + + + align:start position:0% +and we can do that with computers so uh +when I did this I mean it's uh this is + + align:start position:0% +when I did this I mean it's uh this is + + + align:start position:0% +when I did this I mean it's uh this is +article I think like 13 14 years old uh + + align:start position:0% +article I think like 13 14 years old uh + + + align:start position:0% +article I think like 13 14 years old uh +it's before um before python was big so + + align:start position:0% +it's before um before python was big so + + + align:start position:0% +it's before um before python was big so +I used Pearl and I just did find U find + + align:start position:0% +I used Pearl and I just did find U find + + + align:start position:0% +I used Pearl and I just did find U find +and find the hypothetical total number + + align:start position:0% +and find the hypothetical total number + + + align:start position:0% +and find the hypothetical total number +of manuscripts given all the things that + + align:start position:0% +of manuscripts given all the things that + + + align:start position:0% +of manuscripts given all the things that +we know and so on so on and um we're + + align:start position:0% +we know and so on so on and um we're + + + align:start position:0% +we know and so on so on and um we're +able for each of um four + + align:start position:0% +able for each of um four + + + align:start position:0% +able for each of um four +different uh genas these are different + + align:start position:0% +different uh genas these are different + + + align:start position:0% +different uh genas these are different +types of music we're able to figure out + + align:start position:0% +types of music we're able to figure out + + + align:start position:0% +types of music we're able to figure out +what percentage of the pieces are + + align:start position:0% +what percentage of the pieces are + + + align:start position:0% +what percentage of the pieces are +probably missing these are you know I'm + + align:start position:0% +probably missing these are you know I'm + + + align:start position:0% +probably missing these are you know I'm +uh there's error bars on this is rough + + align:start position:0% +uh there's error bars on this is rough + + + align:start position:0% +uh there's error bars on this is rough +guesses um but we can see that the + + align:start position:0% +guesses um but we can see that the + + + align:start position:0% +guesses um but we can see that the +percentage of missing pieces maybe in + + align:start position:0% +percentage of missing pieces maybe in + + + align:start position:0% +percentage of missing pieces maybe in +only + + align:start position:0% +only + + + align:start position:0% +only +one in only one of the genres is it + + align:start position:0% +one in only one of the genres is it + + + align:start position:0% +one in only one of the genres is it +predicted to be more than the number of + + align:start position:0% +predicted to be more than the number of + + + align:start position:0% +predicted to be more than the number of +total number pieces than you know than + + align:start position:0% +total number pieces than you know than + + + align:start position:0% +total number pieces than you know than +the number of surviving pieces in fact + + align:start position:0% +the number of surviving pieces in fact + + + align:start position:0% +the number of surviving pieces in fact +for some of these genres we predict that + + align:start position:0% +for some of these genres we predict that + + + align:start position:0% +for some of these genres we predict that +hey we have almost everything + + align:start position:0% +hey we have almost everything + + + align:start position:0% +hey we have almost everything +there + + align:start position:0% +there + + + align:start position:0% +there +um so one of the things we could look at + + align:start position:0% +um so one of the things we could look at + + + align:start position:0% +um so one of the things we could look at +instead of saying uh how many pieces + + align:start position:0% +instead of saying uh how many pieces + + + align:start position:0% +instead of saying uh how many pieces +were once copied but no longer exist we + + align:start position:0% +were once copied but no longer exist we + + + align:start position:0% +were once copied but no longer exist we +can take that total number and say wow + + align:start position:0% +can take that total number and say wow + + + align:start position:0% +can take that total number and say wow +maybe we have all but 25% of + + align:start position:0% + + + + align:start position:0% + +them now there were a lot of assumptions + + align:start position:0% +them now there were a lot of assumptions + + + align:start position:0% +them now there were a lot of assumptions +that went into that um that scribes are + + align:start position:0% +that went into that um that scribes are + + + align:start position:0% +that went into that um that scribes are +correcting things randomly and so on and + + align:start position:0% +correcting things randomly and so on and + + + align:start position:0% +correcting things randomly and so on and +so forth and that you know that there's + + align:start position:0% +so forth and that you know that there's + + + align:start position:0% +so forth and that you know that there's +not pieces that are more popular than + + align:start position:0% +not pieces that are more popular than + + + align:start position:0% +not pieces that are more popular than +each other and so on and so in the + + align:start position:0% +each other and so on and so in the + + + align:start position:0% +each other and so on and so in the +article that I wrote there's um ways + + align:start position:0% +article that I wrote there's um ways + + + align:start position:0% +article that I wrote there's um ways +that you can compensate for this and + + align:start position:0% +that you can compensate for this and + + + align:start position:0% +that you can compensate for this and +ways that we can test for for instance + + align:start position:0% +ways that we can test for for instance + + + align:start position:0% +ways that we can test for for instance +we can hold out um 10% of the + + align:start position:0% +we can hold out um 10% of the + + + align:start position:0% +we can hold out um 10% of the +manuscripts at random and then say not + + align:start position:0% +manuscripts at random and then say not + + + align:start position:0% +manuscripts at random and then say not +just how many pieces would um would we + + align:start position:0% +just how many pieces would um would we + + + align:start position:0% +just how many pieces would um would we +expect to um would you know would we + + align:start position:0% +expect to um would you know would we + + + align:start position:0% +expect to um would you know would we +expect we lost but if we gained 10 more + + align:start position:0% +expect we lost but if we gained 10 more + + + align:start position:0% +expect we lost but if we gained 10 more +manuscripts how many more pieces would + + align:start position:0% +manuscripts how many more pieces would + + + align:start position:0% +manuscripts how many more pieces would +we expect to have that we didn't know + + align:start position:0% +we expect to have that we didn't know + + + align:start position:0% +we expect to have that we didn't know +already and then we can look at okay now + + align:start position:0% +already and then we can look at okay now + + + align:start position:0% +already and then we can look at okay now +put those 10 men get back and voila uh I + + align:start position:0% +put those 10 men get back and voila uh I + + + align:start position:0% +put those 10 men get back and voila uh I +think I can't remember off the top of my + + align:start position:0% +think I can't remember off the top of my + + + align:start position:0% +think I can't remember off the top of my +head right now I you know one of those + + align:start position:0% +head right now I you know one of those + + + align:start position:0% +head right now I you know one of those +things I published so I don't have to + + align:start position:0% +things I published so I don't have to + + + align:start position:0% +things I published so I don't have to +remember but uh I think that the + + align:start position:0% +remember but uh I think that the + + + align:start position:0% +remember but uh I think that the +percentage of pieces that were lost I + + align:start position:0% +percentage of pieces that were lost I + + + align:start position:0% +percentage of pieces that were lost I +think I think it was you know within 10% + + align:start position:0% +think I think it was you know within 10% + + + align:start position:0% +think I think it was you know within 10% +of something or so so these models were + + align:start position:0% +of something or so so these models were + + + align:start position:0% +of something or so so these models were +pretty pretty good so we can use this + + align:start position:0% +pretty pretty good so we can use this + + + align:start position:0% +pretty pretty good so we can use this +mathematical thinking and just a little + + align:start position:0% +mathematical thinking and just a little + + + align:start position:0% +mathematical thinking and just a little +bit of programming to answer questions + + align:start position:0% +bit of programming to answer questions + + + align:start position:0% +bit of programming to answer questions +that were thought to be completely + + align:start position:0% +that were thought to be completely + + + align:start position:0% +that were thought to be completely +unanswerable in + + align:start position:0% +unanswerable in + + + align:start position:0% +unanswerable in +history thanks \ No newline at end of file diff --git a/k_VJo1Vrl6E.txt b/k_VJo1Vrl6E.txt new file mode 100644 index 0000000000000000000000000000000000000000..4926660b59d8ece257008fa7fb54d773badd0c80 --- /dev/null +++ b/k_VJo1Vrl6E.txt @@ -0,0 +1,2091 @@ +align:start position:0% + +so now that we've talked about + + align:start position:0% +so now that we've talked about + + + align:start position:0% +so now that we've talked about +the different dynamics of droplets in + + align:start position:0% +the different dynamics of droplets in + + + align:start position:0% +the different dynamics of droplets in +the air + + align:start position:0% +the air + + + align:start position:0% +the air +we can think about how different types + + align:start position:0% +we can think about how different types + + + align:start position:0% +we can think about how different types +of pathogen can leverage those droplets + + align:start position:0% +of pathogen can leverage those droplets + + + align:start position:0% +of pathogen can leverage those droplets +to transmit + + align:start position:0% +to transmit + + + align:start position:0% +to transmit +from one person to another through + + align:start position:0% +from one person to another through + + + align:start position:0% +from one person to another through +respiration through the air + + align:start position:0% +respiration through the air + + + align:start position:0% +respiration through the air +so let's begin with bacteria so there + + align:start position:0% +so let's begin with bacteria so there + + + align:start position:0% +so let's begin with bacteria so there +are many different kinds of bacteria the + + align:start position:0% +are many different kinds of bacteria the + + + align:start position:0% +are many different kinds of bacteria the +typical size + + align:start position:0% +typical size + + + align:start position:0% +typical size +of a single bacterium is on the order of + + align:start position:0% +of a single bacterium is on the order of + + + align:start position:0% +of a single bacterium is on the order of +several microns so let's just say you + + align:start position:0% +several microns so let's just say you + + + align:start position:0% +several microns so let's just say you +know 1 + + align:start position:0% +know 1 + + + align:start position:0% +know 1 +to 10 microns + + align:start position:0% +to 10 microns + + + align:start position:0% +to 10 microns +on the other hand bacteria can also + + align:start position:0% +on the other hand bacteria can also + + + align:start position:0% +on the other hand bacteria can also +exist in colonies or larger structures + + align:start position:0% +exist in colonies or larger structures + + + align:start position:0% +exist in colonies or larger structures +and that does determine to some extent + + align:start position:0% +and that does determine to some extent + + + align:start position:0% +and that does determine to some extent +what kinds of droplets + + align:start position:0% +what kinds of droplets + + + align:start position:0% +what kinds of droplets +can transmit those bacteria so let's + + align:start position:0% +can transmit those bacteria so let's + + + align:start position:0% +can transmit those bacteria so let's +begin with an example of a large drop + + align:start position:0% +begin with an example of a large drop + + + align:start position:0% +begin with an example of a large drop +bacteria which is typically going to be + + align:start position:0% +bacteria which is typically going to be + + + align:start position:0% +bacteria which is typically going to be +found in large drops + + align:start position:0% +found in large drops + + + align:start position:0% +found in large drops +and that would be + + align:start position:0% + + + + align:start position:0% + +the bacteria that causes strep throat + + align:start position:0% +the bacteria that causes strep throat + + + align:start position:0% +the bacteria that causes strep throat +the streptococcus + + align:start position:0% +the streptococcus + + + align:start position:0% +the streptococcus +so the streptococcus bacteria which is + + align:start position:0% +so the streptococcus bacteria which is + + + align:start position:0% +so the streptococcus bacteria which is +shown here + + align:start position:0% +shown here + + + align:start position:0% +shown here +has a typical size that's around two + + align:start position:0% +has a typical size that's around two + + + align:start position:0% +has a typical size that's around two +microns so it's on the smaller end + + align:start position:0% +microns so it's on the smaller end + + + align:start position:0% +microns so it's on the smaller end +and it forms chains + + align:start position:0% +and it forms chains + + + align:start position:0% +and it forms chains +and even larger colonies that may have + + align:start position:0% +and even larger colonies that may have + + + align:start position:0% +and even larger colonies that may have +different structures + + align:start position:0% +different structures + + + align:start position:0% +different structures +and the total size of the colonies can + + align:start position:0% +and the total size of the colonies can + + + align:start position:0% +and the total size of the colonies can +vary + + align:start position:0% +vary + + + align:start position:0% +vary +to be as big as even 500 microns + + align:start position:0% +to be as big as even 500 microns + + + align:start position:0% +to be as big as even 500 microns +so it may not be always that big but it + + align:start position:0% +so it may not be always that big but it + + + align:start position:0% +so it may not be always that big but it +might be let's say 50 to 500 micron + + align:start position:0% +might be let's say 50 to 500 micron + + + align:start position:0% +might be let's say 50 to 500 micron +sort of colonies and they can often be + + align:start position:0% +sort of colonies and they can often be + + + align:start position:0% +sort of colonies and they can often be +these sort of stringy type structures + + align:start position:0% +these sort of stringy type structures + + + align:start position:0% +these sort of stringy type structures +and so as a result those require fairly + + align:start position:0% +and so as a result those require fairly + + + align:start position:0% +and so as a result those require fairly +large droplets + + align:start position:0% +large droplets + + + align:start position:0% +large droplets +now just simply knowing that we have + + align:start position:0% +now just simply knowing that we have + + + align:start position:0% +now just simply knowing that we have +large droplet tells us + + align:start position:0% +large droplet tells us + + + align:start position:0% +large droplet tells us +a lot about how this bacteria can + + align:start position:0% +a lot about how this bacteria can + + + align:start position:0% +a lot about how this bacteria can +actually transmit and what measures must + + align:start position:0% +actually transmit and what measures must + + + align:start position:0% +actually transmit and what measures must +be taken against it + + align:start position:0% +be taken against it + + + align:start position:0% +be taken against it +because as soon as we have large drops + + align:start position:0% +because as soon as we have large drops + + + align:start position:0% +because as soon as we have large drops +then what it means is that we have + + align:start position:0% +then what it means is that we have + + + align:start position:0% +then what it means is that we have +fast settling so we know drops that are + + align:start position:0% +fast settling so we know drops that are + + + align:start position:0% +fast settling so we know drops that are +in this size range are going to fall to + + align:start position:0% +in this size range are going to fall to + + + align:start position:0% +in this size range are going to fall to +the ground within a few seconds + + align:start position:0% +the ground within a few seconds + + + align:start position:0% +the ground within a few seconds +and even if you cough them with a lot of + + align:start position:0% +and even if you cough them with a lot of + + + align:start position:0% +and even if you cough them with a lot of +a big velocity + + align:start position:0% +a big velocity + + + align:start position:0% +a big velocity +which is something we'll talk about + + align:start position:0% +which is something we'll talk about + + + align:start position:0% +which is something we'll talk about +later in this in these lectures + + align:start position:0% +later in this in these lectures + + + align:start position:0% +later in this in these lectures +then still in only a few seconds those + + align:start position:0% +then still in only a few seconds those + + + align:start position:0% +then still in only a few seconds those +droplets can sediment + + align:start position:0% +droplets can sediment + + + align:start position:0% +droplets can sediment +out and they really don't go very far + + align:start position:0% +out and they really don't go very far + + + align:start position:0% +out and they really don't go very far +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and so they're fast settling and so what + + align:start position:0% +and so they're fast settling and so what + + + align:start position:0% +and so they're fast settling and so what +that means + + align:start position:0% +that means + + + align:start position:0% +that means +is that we have either foam white + + align:start position:0% + + + + align:start position:0% + +transmission + + align:start position:0% +transmission + + + align:start position:0% +transmission +where those droplets settle on the + + align:start position:0% +where those droplets settle on the + + + align:start position:0% +where those droplets settle on the +ground or on some other surface + + align:start position:0% +ground or on some other surface + + + align:start position:0% +ground or on some other surface +somebody touches that surface touches + + align:start position:0% +somebody touches that surface touches + + + align:start position:0% +somebody touches that surface touches +their eyes and so that's one method of + + align:start position:0% +their eyes and so that's one method of + + + align:start position:0% +their eyes and so that's one method of +transmission + + align:start position:0% +transmission + + + align:start position:0% +transmission +we could also have a direct + + align:start position:0% +we could also have a direct + + + align:start position:0% +we could also have a direct +airborne transmission where + + align:start position:0% +airborne transmission where + + + align:start position:0% +airborne transmission where +let's say i cough or breathe on you and + + align:start position:0% +let's say i cough or breathe on you and + + + align:start position:0% +let's say i cough or breathe on you and +the droplets end up in your face and + + align:start position:0% +the droplets end up in your face and + + + align:start position:0% +the droplets end up in your face and +maybe + + align:start position:0% +maybe + + + align:start position:0% +maybe +directly on your eyes or maybe you + + align:start position:0% +directly on your eyes or maybe you + + + align:start position:0% +directly on your eyes or maybe you +breathe them in so there could be also + + align:start position:0% +breathe them in so there could be also + + + align:start position:0% +breathe them in so there could be also +direct airborne transmission for some of + + align:start position:0% +direct airborne transmission for some of + + + align:start position:0% +direct airborne transmission for some of +the smaller size droplets or for large + + align:start position:0% +the smaller size droplets or for large + + + align:start position:0% +the smaller size droplets or for large +droplets which are ejected from let's + + align:start position:0% +droplets which are ejected from let's + + + align:start position:0% +droplets which are ejected from let's +say a cough or something + + align:start position:0% +say a cough or something + + + align:start position:0% +say a cough or something +and so what that means that the way that + + align:start position:0% +and so what that means that the way that + + + align:start position:0% +and so what that means that the way that +we protect against bacterial + + align:start position:0% +we protect against bacterial + + + align:start position:0% +we protect against bacterial +transmission of disease + + align:start position:0% +transmission of disease + + + align:start position:0% +transmission of disease +is for example for the fomites we will + + align:start position:0% +is for example for the fomites we will + + + align:start position:0% +is for example for the fomites we will +disinfect surfaces + + align:start position:0% + + + + align:start position:0% + +we can wash hands of course + + align:start position:0% + + + + align:start position:0% + +and we will avoid touching + + align:start position:0% +and we will avoid touching + + + align:start position:0% +and we will avoid touching +eyes or nose + + align:start position:0% + + + + align:start position:0% + +so those are pretty basic measures at + + align:start position:0% +so those are pretty basic measures at + + + align:start position:0% +so those are pretty basic measures at +the same time if we're worried about the + + align:start position:0% +the same time if we're worried about the + + + align:start position:0% +the same time if we're worried about the +direct + + align:start position:0% +direct + + + align:start position:0% +direct +uh transmission of the droplets from + + align:start position:0% +uh transmission of the droplets from + + + align:start position:0% +uh transmission of the droplets from +especially coughing or sneezing larger + + align:start position:0% +especially coughing or sneezing larger + + + align:start position:0% +especially coughing or sneezing larger +droplets + + align:start position:0% +droplets + + + align:start position:0% +droplets +then what else can we do well we could + + align:start position:0% +then what else can we do well we could + + + align:start position:0% +then what else can we do well we could +have plastic shields + + align:start position:0% + + + + align:start position:0% + +either worn over the face or maybe a + + align:start position:0% +either worn over the face or maybe a + + + align:start position:0% +either worn over the face or maybe a +barrier between yourself + + align:start position:0% +barrier between yourself + + + align:start position:0% +barrier between yourself +and some other person that you're + + align:start position:0% +and some other person that you're + + + align:start position:0% +and some other person that you're +interacting with to avoid that sort of + + align:start position:0% +interacting with to avoid that sort of + + + align:start position:0% +interacting with to avoid that sort of +projectile transmission of large + + align:start position:0% +projectile transmission of large + + + align:start position:0% +projectile transmission of large +droplets and + + align:start position:0% +droplets and + + + align:start position:0% +droplets and +also we will get the six foot rule + + align:start position:0% +also we will get the six foot rule + + + align:start position:0% +also we will get the six foot rule +which is just an example of a social + + align:start position:0% +which is just an example of a social + + + align:start position:0% +which is just an example of a social +distancing + + align:start position:0% +distancing + + + align:start position:0% +distancing +measure + + align:start position:0% + + + + align:start position:0% + +which is recommended to avoid this sort + + align:start position:0% +which is recommended to avoid this sort + + + align:start position:0% +which is recommended to avoid this sort +of direct airborne transmission + + align:start position:0% +of direct airborne transmission + + + align:start position:0% +of direct airborne transmission +again coming back to the idea that + + align:start position:0% +again coming back to the idea that + + + align:start position:0% +again coming back to the idea that +droplets of the size typically settle in + + align:start position:0% +droplets of the size typically settle in + + + align:start position:0% +droplets of the size typically settle in +a few seconds + + align:start position:0% +a few seconds + + + align:start position:0% +a few seconds +and if you look at the typical + + align:start position:0% +and if you look at the typical + + + align:start position:0% +and if you look at the typical +velocities of ejection especially from + + align:start position:0% +velocities of ejection especially from + + + align:start position:0% +velocities of ejection especially from +coughs and sneezes + + align:start position:0% +coughs and sneezes + + + align:start position:0% +coughs and sneezes +then they will settle in about six feet + + align:start position:0% +then they will settle in about six feet + + + align:start position:0% +then they will settle in about six feet +or so or about two meters + + align:start position:0% +or so or about two meters + + + align:start position:0% +or so or about two meters +although that's not a hard rule the six + + align:start position:0% +although that's not a hard rule the six + + + align:start position:0% +although that's not a hard rule the six +foot rule happens to be + + align:start position:0% +foot rule happens to be + + + align:start position:0% +foot rule happens to be +for the united states centers for + + align:start position:0% +for the united states centers for + + + align:start position:0% +for the united states centers for +disease control + + align:start position:0% +disease control + + + align:start position:0% +disease control +the cdc but there's also one meter rule + + align:start position:0% +the cdc but there's also one meter rule + + + align:start position:0% +the cdc but there's also one meter rule +which is basically a three-foot rule + + align:start position:0% +which is basically a three-foot rule + + + align:start position:0% +which is basically a three-foot rule +for the world health organization so + + align:start position:0% +for the world health organization so + + + align:start position:0% +for the world health organization so +this is not + + align:start position:0% +this is not + + + align:start position:0% +this is not +you know extremely well-defined what + + align:start position:0% +you know extremely well-defined what + + + align:start position:0% +you know extremely well-defined what +should be the distance but clearly if + + align:start position:0% +should be the distance but clearly if + + + align:start position:0% +should be the distance but clearly if +you + + align:start position:0% +you + + + align:start position:0% +you +are able to stay away from people then + + align:start position:0% +are able to stay away from people then + + + align:start position:0% +are able to stay away from people then +even if they're coughing or breathing + + align:start position:0% +even if they're coughing or breathing + + + align:start position:0% +even if they're coughing or breathing +these large droplets + + align:start position:0% +these large droplets + + + align:start position:0% +these large droplets +with only a few seconds of settling time + + align:start position:0% +with only a few seconds of settling time + + + align:start position:0% +with only a few seconds of settling time +those droplets will hit the floor + + align:start position:0% +those droplets will hit the floor + + + align:start position:0% +those droplets will hit the floor +and will not be able to infect you + + align:start position:0% +and will not be able to infect you + + + align:start position:0% +and will not be able to infect you +directly and so it's important to + + align:start position:0% +directly and so it's important to + + + align:start position:0% +directly and so it's important to +maintain that kind of distancing + + align:start position:0% +maintain that kind of distancing + + + align:start position:0% +maintain that kind of distancing +okay now there are also other kinds of + + align:start position:0% +okay now there are also other kinds of + + + align:start position:0% +okay now there are also other kinds of +bacteria + + align:start position:0% +bacteria + + + align:start position:0% +bacteria +that don't form these larger colonies + + align:start position:0% +that don't form these larger colonies + + + align:start position:0% +that don't form these larger colonies +and they remain + + align:start position:0% +and they remain + + + align:start position:0% +and they remain +small even when they're transmitting and + + align:start position:0% +small even when they're transmitting and + + + align:start position:0% +small even when they're transmitting and +a classic example of that which can be + + align:start position:0% +a classic example of that which can be + + + align:start position:0% +a classic example of that which can be +transmitted + + align:start position:0% +transmitted + + + align:start position:0% +transmitted +in small drops is tuberculosis + + align:start position:0% +in small drops is tuberculosis + + + align:start position:0% +in small drops is tuberculosis +in fact the original study in the 1930s + + align:start position:0% +in fact the original study in the 1930s + + + align:start position:0% +in fact the original study in the 1930s +uh + + align:start position:0% +uh + + + align:start position:0% +uh +also involving wells uh was + + align:start position:0% +also involving wells uh was + + + align:start position:0% +also involving wells uh was +for that that led to this essentially + + align:start position:0% +for that that led to this essentially + + + align:start position:0% +for that that led to this essentially +this the distancing rules and the so + + align:start position:0% +this the distancing rules and the so + + + align:start position:0% +this the distancing rules and the so +the sixth rule in particular had to do + + align:start position:0% +the sixth rule in particular had to do + + + align:start position:0% +the sixth rule in particular had to do +with + + align:start position:0% +with + + + align:start position:0% +with +coughing and sneezing and the distance + + align:start position:0% +coughing and sneezing and the distance + + + align:start position:0% +coughing and sneezing and the distance +over which droplets could be transmitted + + align:start position:0% +over which droplets could be transmitted + + + align:start position:0% +over which droplets could be transmitted +containing tuberculosis now tuberculosis + + align:start position:0% +containing tuberculosis now tuberculosis + + + align:start position:0% +containing tuberculosis now tuberculosis +on the other hand + + align:start position:0% +on the other hand + + + align:start position:0% +on the other hand +as you can see um in the image is a + + align:start position:0% +as you can see um in the image is a + + + align:start position:0% +as you can see um in the image is a +rod-like bacteria that's quite small so + + align:start position:0% +rod-like bacteria that's quite small so + + + align:start position:0% +rod-like bacteria that's quite small so +the length + + align:start position:0% +the length + + + align:start position:0% +the length +is several microns typically two to four + + align:start position:0% +is several microns typically two to four + + + align:start position:0% +is several microns typically two to four +but the radius is half a micron or even + + align:start position:0% +but the radius is half a micron or even + + + align:start position:0% +but the radius is half a micron or even +down to 0.2 microns so actually we're + + align:start position:0% +down to 0.2 microns so actually we're + + + align:start position:0% +down to 0.2 microns so actually we're +really talking about hundreds of + + align:start position:0% +really talking about hundreds of + + + align:start position:0% +really talking about hundreds of +nanometers in length + + align:start position:0% +nanometers in length + + + align:start position:0% +nanometers in length +so these are kind of you know little + + align:start position:0% +so these are kind of you know little + + + align:start position:0% +so these are kind of you know little +rods like this + + align:start position:0% +rods like this + + + align:start position:0% +rods like this +and they can be contained in a pretty + + align:start position:0% +and they can be contained in a pretty + + + align:start position:0% +and they can be contained in a pretty +small droplet you know these big + + align:start position:0% +small droplet you know these big + + + align:start position:0% +small droplet you know these big +colonies right + + align:start position:0% +colonies right + + + align:start position:0% +colonies right +of course require something much larger + + align:start position:0% +of course require something much larger + + + align:start position:0% +of course require something much larger +so these droplets could be small + + align:start position:0% +so these droplets could be small + + + align:start position:0% +so these droplets could be small +and so there is a possibility here of + + align:start position:0% +and so there is a possibility here of + + + align:start position:0% +and so there is a possibility here of +larger aerosol transmission by larger i + + align:start position:0% +larger aerosol transmission by larger i + + + align:start position:0% +larger aerosol transmission by larger i +mean + + align:start position:0% +mean + + + align:start position:0% +mean +in the range of sort of 5 to 10 microns + + align:start position:0% +in the range of sort of 5 to 10 microns + + + align:start position:0% +in the range of sort of 5 to 10 microns +so of course tuberculos also can be + + align:start position:0% +so of course tuberculos also can be + + + align:start position:0% +so of course tuberculos also can be +contained in much larger droplets + + align:start position:0% +contained in much larger droplets + + + align:start position:0% +contained in much larger droplets +which you know fall to the ground as + + align:start position:0% +which you know fall to the ground as + + + align:start position:0% +which you know fall to the ground as +we've just been describing + + align:start position:0% +we've just been describing + + + align:start position:0% +we've just been describing +but tuberculosis is a bit different in + + align:start position:0% +but tuberculosis is a bit different in + + + align:start position:0% +but tuberculosis is a bit different in +that these individual + + align:start position:0% +that these individual + + + align:start position:0% +that these individual +bacteria could be transmitted airborne + + align:start position:0% +bacteria could be transmitted airborne + + + align:start position:0% +bacteria could be transmitted airborne +in larger aerosol droplets + + align:start position:0% +in larger aerosol droplets + + + align:start position:0% +in larger aerosol droplets +and in fact that is what is found if you + + align:start position:0% +and in fact that is what is found if you + + + align:start position:0% +and in fact that is what is found if you +have + + align:start position:0% +have + + + align:start position:0% +have +this size of droplet then it turns out + + align:start position:0% +this size of droplet then it turns out + + + align:start position:0% +this size of droplet then it turns out +for example if my radius + + align:start position:0% +for example if my radius + + + align:start position:0% +for example if my radius +is let's say greater than 4 microns + + align:start position:0% +is let's say greater than 4 microns + + + align:start position:0% +is let's say greater than 4 microns +then the settling velocity you can find + + align:start position:0% +then the settling velocity you can find + + + align:start position:0% +then the settling velocity you can find +given the density of aqueous fluids + + align:start position:0% +given the density of aqueous fluids + + + align:start position:0% +given the density of aqueous fluids +is around two bigger than two + + align:start position:0% +is around two bigger than two + + + align:start position:0% +is around two bigger than two +millimeters a second + + align:start position:0% +millimeters a second + + + align:start position:0% +millimeters a second +and then the time to drop from a typical + + align:start position:0% +and then the time to drop from a typical + + + align:start position:0% +and then the time to drop from a typical +person's height to the ground + + align:start position:0% +person's height to the ground + + + align:start position:0% +person's height to the ground +is around 15 minutes so these are not + + align:start position:0% +is around 15 minutes so these are not + + + align:start position:0% +is around 15 minutes so these are not +the kind of aerosols that might stick + + align:start position:0% +the kind of aerosols that might stick + + + align:start position:0% +the kind of aerosols that might stick +around + + align:start position:0% +around + + + align:start position:0% +around +for hours like the submicron aerosols + + align:start position:0% +for hours like the submicron aerosols + + + align:start position:0% +for hours like the submicron aerosols +that are also + + align:start position:0% +that are also + + + align:start position:0% +that are also +produced by breathing and which are too + + align:start position:0% +produced by breathing and which are too + + + align:start position:0% +produced by breathing and which are too +small to contain tuberculosis + + align:start position:0% +small to contain tuberculosis + + + align:start position:0% +small to contain tuberculosis +but still these times suggest that + + align:start position:0% +but still these times suggest that + + + align:start position:0% +but still these times suggest that +tuberculosis can linger in the air + + align:start position:0% +tuberculosis can linger in the air + + + align:start position:0% +tuberculosis can linger in the air +and in fact a + + align:start position:0% + + + + align:start position:0% + +long distance + + align:start position:0% + + + + align:start position:0% + +airborne transmission + + align:start position:0% + + + + align:start position:0% + +is not only possible as we've just + + align:start position:0% +is not only possible as we've just + + + align:start position:0% +is not only possible as we've just +argued based on physical rounds but it's + + align:start position:0% +argued based on physical rounds but it's + + + align:start position:0% +argued based on physical rounds but it's +been directly verified + + align:start position:0% + + + + align:start position:0% + +that's been done both in human studies + + align:start position:0% +that's been done both in human studies + + + align:start position:0% +that's been done both in human studies +and also in animal studies + + align:start position:0% +and also in animal studies + + + align:start position:0% +and also in animal studies +where they can have two different + + align:start position:0% +where they can have two different + + + align:start position:0% +where they can have two different +compartments with a sick animal such as + + align:start position:0% +compartments with a sick animal such as + + + align:start position:0% +compartments with a sick animal such as +a ferret + + align:start position:0% +a ferret + + + align:start position:0% +a ferret +or some other animal model and the + + align:start position:0% +or some other animal model and the + + + align:start position:0% +or some other animal model and the +disease is spread to another animal + + align:start position:0% +disease is spread to another animal + + + align:start position:0% +disease is spread to another animal +who's had no direct contact but is + + align:start position:0% +who's had no direct contact but is + + + align:start position:0% +who's had no direct contact but is +sharing the same air so the airborne + + align:start position:0% +sharing the same air so the airborne + + + align:start position:0% +sharing the same air so the airborne +transmission is definitely + + align:start position:0% +transmission is definitely + + + align:start position:0% +transmission is definitely +verified in this case and now you might + + align:start position:0% +verified in this case and now you might + + + align:start position:0% +verified in this case and now you might +ask well what are the preventive + + align:start position:0% +ask well what are the preventive + + + align:start position:0% +ask well what are the preventive +measures + + align:start position:0% +measures + + + align:start position:0% +measures +so instead of all of these measures like + + align:start position:0% +so instead of all of these measures like + + + align:start position:0% +so instead of all of these measures like +plastic shields and six foot rule + + align:start position:0% +plastic shields and six foot rule + + + align:start position:0% +plastic shields and six foot rule +if you actually airborne transmission if + + align:start position:0% +if you actually airborne transmission if + + + align:start position:0% +if you actually airborne transmission if +there's a shield then the air is going + + align:start position:0% +there's a shield then the air is going + + + align:start position:0% +there's a shield then the air is going +to go right around the shield and it's + + align:start position:0% +to go right around the shield and it's + + + align:start position:0% +to go right around the shield and it's +going to go everywhere else in the room + + align:start position:0% +going to go everywhere else in the room + + + align:start position:0% +going to go everywhere else in the room +because the air is flowing + + align:start position:0% +because the air is flowing + + + align:start position:0% +because the air is flowing +okay in the same way that when you light + + align:start position:0% +okay in the same way that when you light + + + align:start position:0% +okay in the same way that when you light +a candle and you see where the smoke is + + align:start position:0% +a candle and you see where the smoke is + + + align:start position:0% +a candle and you see where the smoke is +going it quickly spreads around the + + align:start position:0% +going it quickly spreads around the + + + align:start position:0% +going it quickly spreads around the +whole room it doesn't care if there's a + + align:start position:0% +whole room it doesn't care if there's a + + + align:start position:0% +whole room it doesn't care if there's a +shield there as long as there's a way + + align:start position:0% +shield there as long as there's a way + + + align:start position:0% +shield there as long as there's a way +around the shield that's going to find + + align:start position:0% +around the shield that's going to find + + + align:start position:0% +around the shield that's going to find +that + + align:start position:0% +that + + + align:start position:0% +that +and so instead when you're trying to + + align:start position:0% +and so instead when you're trying to + + + align:start position:0% +and so instead when you're trying to +protect against airborne transmission + + align:start position:0% +protect against airborne transmission + + + align:start position:0% +protect against airborne transmission +your protective measures are things like + + align:start position:0% +your protective measures are things like + + + align:start position:0% +your protective measures are things like +ventilation so bring in fresh air from + + align:start position:0% +ventilation so bring in fresh air from + + + align:start position:0% +ventilation so bring in fresh air from +outside or opening your windows + + align:start position:0% +outside or opening your windows + + + align:start position:0% +outside or opening your windows +air filtration + + align:start position:0% +air filtration + + + align:start position:0% +air filtration +where you're passing the air through a + + align:start position:0% +where you're passing the air through a + + + align:start position:0% +where you're passing the air through a +filter which is going to filter out the + + align:start position:0% +filter which is going to filter out the + + + align:start position:0% +filter which is going to filter out the +particles by size or by charge + + align:start position:0% +particles by size or by charge + + + align:start position:0% +particles by size or by charge +or some other mechanism like that and + + align:start position:0% +or some other mechanism like that and + + + align:start position:0% +or some other mechanism like that and +also becomes more and more important + + align:start position:0% +also becomes more and more important + + + align:start position:0% +also becomes more and more important +to wear face masks because then at least + + align:start position:0% +to wear face masks because then at least + + + align:start position:0% +to wear face masks because then at least +you can block these droplets at the + + align:start position:0% +you can block these droplets at the + + + align:start position:0% +you can block these droplets at the +source + + align:start position:0% +source + + + align:start position:0% +source +and also at the target as we shall + + align:start position:0% +and also at the target as we shall + + + align:start position:0% +and also at the target as we shall +discuss in much + + align:start position:0% +discuss in much + + + align:start position:0% +discuss in much +more detail so what we see here is just + + align:start position:0% +more detail so what we see here is just + + + align:start position:0% +more detail so what we see here is just +knowing simply the size of the pathogen + + align:start position:0% +knowing simply the size of the pathogen + + + align:start position:0% +knowing simply the size of the pathogen +and understanding the dynamic the + + align:start position:0% +and understanding the dynamic the + + + align:start position:0% +and understanding the dynamic the +physics of droplets + + align:start position:0% +physics of droplets + + + align:start position:0% +physics of droplets +in the air helps us to understand the + + align:start position:0% +in the air helps us to understand the + + + align:start position:0% +in the air helps us to understand the +modes of transmission which are written + + align:start position:0% +modes of transmission which are written + + + align:start position:0% +modes of transmission which are written +here in blue + + align:start position:0% +here in blue + + + align:start position:0% +here in blue +and also the appropriate protective + + align:start position:0% +and also the appropriate protective + + + align:start position:0% +and also the appropriate protective +measures which are written here + + align:start position:0% +measures which are written here + + + align:start position:0% +measures which are written here +in pink to protect against these + + align:start position:0% +in pink to protect against these + + + align:start position:0% +in pink to protect against these +different types + + align:start position:0% +different types + + + align:start position:0% +different types +of transmission \ No newline at end of file diff --git a/klubJGAZDOI.txt b/klubJGAZDOI.txt new file mode 100644 index 0000000000000000000000000000000000000000..8a3a3bb265f6fc1c50e8c15faaa248be2d475707 --- /dev/null +++ b/klubJGAZDOI.txt @@ -0,0 +1,899 @@ +align:start position:0% + +visualizing cultures is a web-based + + align:start position:0% +visualizing cultures is a web-based + + + align:start position:0% +visualizing cultures is a web-based +history uh program which John Da and I + + align:start position:0% +history uh program which John Da and I + + + align:start position:0% +history uh program which John Da and I +started in year 2001 John Da is an + + align:start position:0% +started in year 2001 John Da is an + + + align:start position:0% +started in year 2001 John Da is an +eminent historian of modern Japan he won + + align:start position:0% +eminent historian of modern Japan he won + + + align:start position:0% +eminent historian of modern Japan he won +the pillot prize in 1999 for his book + + align:start position:0% +the pillot prize in 1999 for his book + + + align:start position:0% +the pillot prize in 1999 for his book +embracing + + align:start position:0% +embracing + + + align:start position:0% +embracing +defeat I approached John in uh in + + align:start position:0% +defeat I approached John in uh in + + + align:start position:0% +defeat I approached John in uh in +2000 uh when I knew that open course + + align:start position:0% +2000 uh when I knew that open course + + + align:start position:0% +2000 uh when I knew that open course +Weare was about to go up and I told John + + align:start position:0% +Weare was about to go up and I told John + + + align:start position:0% +Weare was about to go up and I told John +that uh I thought that this would be a + + align:start position:0% +that uh I thought that this would be a + + + align:start position:0% +that uh I thought that this would be a +great platform to to do something new + + align:start position:0% +great platform to to do something new + + + align:start position:0% +great platform to to do something new +with history okay specifically to look + + align:start position:0% +with history okay specifically to look + + + align:start position:0% +with history okay specifically to look +at history not just from text which is + + align:start position:0% +at history not just from text which is + + + align:start position:0% +at history not just from text which is +what historians do but from uh looking + + align:start position:0% +what historians do but from uh looking + + + align:start position:0% +what historians do but from uh looking +at images visuals that have been uh + + align:start position:0% +at images visuals that have been uh + + + align:start position:0% +at images visuals that have been uh +produced by uh + + align:start position:0% +produced by uh + + + align:start position:0% +produced by uh +by people from the historical era and to + + align:start position:0% +by people from the historical era and to + + + align:start position:0% +by people from the historical era and to +try to understand what was going + + align:start position:0% +try to understand what was going + + + align:start position:0% +try to understand what was going +on uh + + align:start position:0% +on uh + + + align:start position:0% +on uh +John surprisingly said + + align:start position:0% +John surprisingly said + + + align:start position:0% +John surprisingly said +yes and so we started we didn't quite + + align:start position:0% +yes and so we started we didn't quite + + + align:start position:0% +yes and so we started we didn't quite +know what you know we were doing at + + align:start position:0% +know what you know we were doing at + + + align:start position:0% +know what you know we were doing at +first but uh we got very lucky with our + + align:start position:0% +first but uh we got very lucky with our + + + align:start position:0% +first but uh we got very lucky with our +first unit which is uh uh commer Matthew + + align:start position:0% +first unit which is uh uh commer Matthew + + + align:start position:0% +first unit which is uh uh commer Matthew +Perry's arrival in Japan in 1853 to open + + align:start position:0% +Perry's arrival in Japan in 1853 to open + + + align:start position:0% +Perry's arrival in Japan in 1853 to open +up Japan which had been essentially + + align:start position:0% +up Japan which had been essentially + + + align:start position:0% +up Japan which had been essentially +isolated closed for 250 years and so you + + align:start position:0% +isolated closed for 250 years and so you + + + align:start position:0% +isolated closed for 250 years and so you +have uh America and Japan come clashing + + align:start position:0% +have uh America and Japan come clashing + + + align:start position:0% +have uh America and Japan come clashing +together in this one moment in history + + align:start position:0% +together in this one moment in history + + + align:start position:0% +together in this one moment in history +and from that this explosion of images + + align:start position:0% +and from that this explosion of images + + + align:start position:0% +and from that this explosion of images +from both sides know Americans uh + + align:start position:0% +from both sides know Americans uh + + + align:start position:0% +from both sides know Americans uh +depicting the Japanese uh and Japanese + + align:start position:0% +depicting the Japanese uh and Japanese + + + align:start position:0% +depicting the Japanese uh and Japanese +depicting per and his man and his ships + + align:start position:0% +depicting per and his man and his ships + + + align:start position:0% +depicting per and his man and his ships +it's just + + align:start position:0% +it's just + + + align:start position:0% +it's just +wonderful and what's really uh + + align:start position:0% +wonderful and what's really uh + + + align:start position:0% +wonderful and what's really uh +interesting is that when you look at + + align:start position:0% +interesting is that when you look at + + + align:start position:0% +interesting is that when you look at +images you get to see things that you + + align:start position:0% +images you get to see things that you + + + align:start position:0% +images you get to see things that you +cannot get from written + + align:start position:0% +cannot get from written + + + align:start position:0% +cannot get from written +material uh we found lots of images + + align:start position:0% +material uh we found lots of images + + + align:start position:0% +material uh we found lots of images +where the Japanese were really curious + + align:start position:0% +where the Japanese were really curious + + + align:start position:0% +where the Japanese were really curious +about Paris men and + + align:start position:0% +about Paris men and + + + align:start position:0% +about Paris men and +drawing + + align:start position:0% +drawing + + + align:start position:0% +drawing +uh you know costumes instruments weapons + + align:start position:0% +uh you know costumes instruments weapons + + + align:start position:0% +uh you know costumes instruments weapons +in minute detail and with with notes to + + align:start position:0% +in minute detail and with with notes to + + + align:start position:0% +in minute detail and with with notes to +go along with them showing just sort of + + align:start position:0% +go along with them showing just sort of + + + align:start position:0% +go along with them showing just sort of +sheer curiosity who are these people you + + align:start position:0% +sheer curiosity who are these people you + + + align:start position:0% +sheer curiosity who are these people you +know + + align:start position:0% +know + + + align:start position:0% +know +how do they live okay how do they talk + + align:start position:0% +how do they live okay how do they talk + + + align:start position:0% +how do they live okay how do they talk +and you saw the same thing on Perry's + + align:start position:0% +and you saw the same thing on Perry's + + + align:start position:0% +and you saw the same thing on Perry's +side uh Perry brought his own + + align:start position:0% +side uh Perry brought his own + + + align:start position:0% +side uh Perry brought his own +artist haa who was a a + + align:start position:0% +artist haa who was a a + + + align:start position:0% +artist haa who was a a +26-year-old + + align:start position:0% +26-year-old + + + align:start position:0% +26-year-old +um artist uh trained in Germany in sort + + align:start position:0% +um artist uh trained in Germany in sort + + + align:start position:0% +um artist uh trained in Germany in sort +of romantic uh style he just fell in + + align:start position:0% +of romantic uh style he just fell in + + + align:start position:0% +of romantic uh style he just fell in +love with Japan yeah and you can tell + + align:start position:0% +love with Japan yeah and you can tell + + + align:start position:0% +love with Japan yeah and you can tell +that in the images he absolutely fell in + + align:start position:0% +that in the images he absolutely fell in + + + align:start position:0% +that in the images he absolutely fell in +love with with this beautiful country so + + align:start position:0% +love with with this beautiful country so + + + align:start position:0% +love with with this beautiful country so +much so that he would sometimes S Paint + + align:start position:0% +much so that he would sometimes S Paint + + + align:start position:0% +much so that he would sometimes S Paint +himself into the picture interacting + + align:start position:0% +himself into the picture interacting + + + align:start position:0% +himself into the picture interacting +with the Japanese and so what you got + + align:start position:0% +with the Japanese and so what you got + + + align:start position:0% +with the Japanese and so what you got +was this one artist depicting Japan uh + + align:start position:0% +was this one artist depicting Japan uh + + + align:start position:0% +was this one artist depicting Japan uh +in a very beautiful very affectionate uh + + align:start position:0% +in a very beautiful very affectionate uh + + + align:start position:0% +in a very beautiful very affectionate uh +way and that's what the Americans saw of + + align:start position:0% +way and that's what the Americans saw of + + + align:start position:0% +way and that's what the Americans saw of +Japan for the first time this is why + + align:start position:0% +Japan for the first time this is why + + + align:start position:0% +Japan for the first time this is why +even to this day you know in this + + align:start position:0% +even to this day you know in this + + + align:start position:0% +even to this day you know in this +country you have this image of Japan as + + align:start position:0% +country you have this image of Japan as + + + align:start position:0% +country you have this image of Japan as +uh very beautiful very very beautiful + + align:start position:0% +uh very beautiful very very beautiful + + + align:start position:0% +uh very beautiful very very beautiful +nature and it really originates with + + align:start position:0% +nature and it really originates with + + + align:start position:0% +nature and it really originates with +highness paintings and so we very much + + align:start position:0% +highness paintings and so we very much + + + align:start position:0% +highness paintings and so we very much +follow the + + align:start position:0% +follow the + + + align:start position:0% +follow the +ocw principle of uh not only making it + + align:start position:0% +ocw principle of uh not only making it + + + align:start position:0% +ocw principle of uh not only making it +available open and free but that + + align:start position:0% +available open and free but that + + + align:start position:0% +available open and free but that +everything is licensed under Creative + + align:start position:0% +everything is licensed under Creative + + + align:start position:0% +everything is licensed under Creative +Commons so that uh these images okay uh + + align:start position:0% +Commons so that uh these images okay uh + + + align:start position:0% +Commons so that uh these images okay uh +which we got from about 200 museums and + + align:start position:0% +which we got from about 200 museums and + + + align:start position:0% +which we got from about 200 museums and +these are major museums both on MFA + + align:start position:0% +these are major museums both on MFA + + + align:start position:0% +these are major museums both on MFA +Sackler in Washington Hong Kong British + + align:start position:0% +Sackler in Washington Hong Kong British + + + align:start position:0% +Sackler in Washington Hong Kong British +uh Museum uh we asked all of them to + + align:start position:0% +uh Museum uh we asked all of them to + + + align:start position:0% +uh Museum uh we asked all of them to +sign an agreement that we could present + + align:start position:0% +sign an agreement that we could present + + + align:start position:0% +sign an agreement that we could present +their images on open on visualizing + + align:start position:0% +their images on open on visualizing + + + align:start position:0% +their images on open on visualizing +Japan on open coare under creative + + align:start position:0% +Japan on open coare under creative + + + align:start position:0% +Japan on open coare under creative +comments and so uh anyone coming + + align:start position:0% +comments and so uh anyone coming + + + align:start position:0% +comments and so uh anyone coming +in and studying uh visualizing cultures + + align:start position:0% +in and studying uh visualizing cultures + + + align:start position:0% +in and studying uh visualizing cultures +can take images and copy them distribute + + align:start position:0% +can take images and copy them distribute + + + align:start position:0% +can take images and copy them distribute +them alter them uh into their own + + align:start position:0% +them alter them uh into their own + + + align:start position:0% +them alter them uh into their own +material and use them you know however + + align:start position:0% +material and use them you know however + + + align:start position:0% +material and use them you know however +they wish + + align:start position:0% +they wish + + + align:start position:0% +they wish +one of the uh populations that we really + + align:start position:0% +one of the uh populations that we really + + + align:start position:0% +one of the uh populations that we really +wanted to work with were School + + align:start position:0% +wanted to work with were School + + + align:start position:0% +wanted to work with were School +teachers and so we did many many + + align:start position:0% +teachers and so we did many many + + + align:start position:0% +teachers and so we did many many +workshops over the years and we trained + + align:start position:0% +workshops over the years and we trained + + + align:start position:0% +workshops over the years and we trained +face Toof face uh around 2,000 teachers + + align:start position:0% +face Toof face uh around 2,000 teachers + + + align:start position:0% +face Toof face uh around 2,000 teachers +okay this is I we I say we uh we worked + + align:start position:0% +okay this is I we I say we uh we worked + + + align:start position:0% +okay this is I we I say we uh we worked +with a uh uh a a wonderful um group out + + align:start position:0% +with a uh uh a a wonderful um group out + + + align:start position:0% +with a uh uh a a wonderful um group out +of University of Colorado that + + align:start position:0% +of University of Colorado that + + + align:start position:0% +of University of Colorado that +specializes in creating East Asian + + align:start position:0% +specializes in creating East Asian + + + align:start position:0% +specializes in creating East Asian +curriculum and work working with + + align:start position:0% +curriculum and work working with + + + align:start position:0% +curriculum and work working with +teachers directly to help them to + + align:start position:0% +teachers directly to help them to + + + align:start position:0% +teachers directly to help them to +incorporate them into their classroom + + align:start position:0% +incorporate them into their classroom + + + align:start position:0% +incorporate them into their classroom +and so they uh ran this series of + + align:start position:0% +and so they uh ran this series of + + + align:start position:0% +and so they uh ran this series of +workshops all over the country and uh as + + align:start position:0% +workshops all over the country and uh as + + + align:start position:0% +workshops all over the country and uh as +far as I know it's still being + + align:start position:0% +far as I know it's still being + + + align:start position:0% +far as I know it's still being +used so high school teachers uh + + align:start position:0% +used so high school teachers uh + + + align:start position:0% +used so high school teachers uh +University professors tell us that + + align:start position:0% +University professors tell us that + + + align:start position:0% +University professors tell us that +they're um using it uh on a regular + + align:start position:0% +they're um using it uh on a regular + + + align:start position:0% +they're um using it uh on a regular +basis couple years ago a uh University + + align:start position:0% +basis couple years ago a uh University + + + align:start position:0% +basis couple years ago a uh University +um had an opening for assistant + + align:start position:0% +um had an opening for assistant + + + align:start position:0% +um had an opening for assistant +professoring Japanese history and uh uh + + align:start position:0% +professoring Japanese history and uh uh + + + align:start position:0% +professoring Japanese history and uh uh +they had uh four finalists and they + + align:start position:0% +they had uh four finalists and they + + + align:start position:0% +they had uh four finalists and they +asked them how do you teach Japanese + + align:start position:0% +asked them how do you teach Japanese + + + align:start position:0% +asked them how do you teach Japanese +history and three of three of them + + align:start position:0% +history and three of three of them + + + align:start position:0% +history and three of three of them +apparently said they used visualizing + + align:start position:0% +apparently said they used visualizing + + + align:start position:0% +apparently said they used visualizing +cultures \ No newline at end of file diff --git a/le8tpXQyYcM.txt b/le8tpXQyYcM.txt new file mode 100644 index 0000000000000000000000000000000000000000..1d06ffeb28caab0abf13a3f54627b3e714739c27 --- /dev/null +++ b/le8tpXQyYcM.txt @@ -0,0 +1,1818 @@ +OPERATOR: -- + +The following content is +provided under a Creative + +Commons license. + +Your support will help MIT +OpenCourseWare continue to + +offer high quality educational +resources for free. + +To make a donation, or view +additional materials from + +hundreds of MIT courses, visit +MIT OpenCourseWare at + +ocw.mit.edu. + +PROFESSOR: At the end of the +lecture on Tuesday, a number + +of people asked me questions, +asked Professor Grimson + +questions, which made it clear +that I had been less than + +clear on at least a few things, +so I want to come back + +and revisit a couple of the +things we talked about at the + +end of the lecture. + +You'll remember that I had drawn +this decision tree, in + +part because it's an important +concept I want you to + +understand, the concept of +decision trees, and also to + +illustrate, I hope, visually, +some things related to dynamic + +programming. + +So we had in that decision tree, +is we had the weight + +vector, and I just given a very +simple one [5,3,2], and + +we had a very simple value +vector, [9,7,8]. + +And then the way we drew the +tree, was we started at the + +top, and said all right, we're +going to first look at item + +number 2, which was the third +item in our list of items, of + +course, and say that we had +five pounds left of weight + +that our knapsack that could +hold, and currently had a + +value of 0. + +And then we made a decision, to +not put that last item in + +the backpack, and said if we +made that decision, the next + +item we had to consider was +item 1, we still had five + +pounds available, and we still +had a weight 0 available. + +Now I, said the next item to +consider is item 1, but really + +what I meant is, 1 and all of +the items proceeding it in the + +list. This is my shorthand for +saying the list up to and + +including items sub 1, +kind of a normal way + +to think about it. + +And then we finish building +the tree, left first step + +first, looking at all the no +branches, 0,5,0 and then we + +were done, that was +one branch. + +We then backed up, and said +let's look at a yes, we'll + +include item number 1. + +Well, what happens here, if +we've included that, it uses + +up all the available weight, +and gave us the value of 9. + +STUDENT: [UNINTELLIGIBLE] + +PROFESSOR: Pardon? + +STUDENT: -- want to be off +the bottom branch. + +PROFESSOR: Yup, Off by 1. + +Yeah, I wanted to come off +this branch, because I've + +backtrack just 1, thank you. + +And then I backtrack up +to this branch, and + +from here we got 0,2,7. + +And I'm not going to draw the +rest of the tree for you here, + +because I drew it last time, and +you don't need to see the + +whole tree. + +The point I wanted to make is +that for every node, except + +the leaves, the leaves are the +bottom of a tree in this case, + +computer scientists are weird, +right, they draw trees where + +the root is at the top, and the +leaves are at the bottom. + +And I don't know why, but since +time immemorial that is + +the way computer scientists +have drawn trees. + +That's why we're not biologists, +I guess. + +We don't understand +these things. + +But what I want you to notice is +that for each node, except + +the leaves, the solution for +that node can be computed from + +the solutions from +it's children. + +So in order to look at the +solution of this node, I + +choose one of the solutions of +it's children, a or b, is the + +best solution if I'm here, and +of course this is the better + +of the 2 solutions. + +If I look at this node, I get to +choose its solution as the + +better of the solution for +this node, and this node. + +All the way up to the top, where +when I have to choose + +the best solution to the whole +problem, it's either the best + +solution to the left node, +or the best solution + +to the right node. + +This happens to be a binary +decision tree. + +There's nothing magic about +there being only two nodes, + +for the knapsack problem, that's +just the way it works + +out, but there are other +problems where there might be + +multiple decisions to make, more +than a or yes or no, but + +it's always the case here that +I have what we last time + +talked about as what? + +Optimal sub structure. + +As I defined it last time, it +means that I can solve a + +problem by finding the optimal +solution to smaller sub + +problems. Classic divide and +conquer that we've seen over + +and over again in the term. + +Take a hard problem, say well, +I can solve it by solving 2 + +smaller problems and combine +their solution, and this case, + +the combining is choosing +the best, it's a or b. + +So then, I went directly from +that way of thinking about the + +problem, to this +straightforward, at the top of + +the slide here, also at the +top of your handout, both + +yesterday and today, a +straightforward implementation + +of max val, that basically +just did this. + +And as you might have guessed, +when you're doing this sort of + +thing, recursion is a very +natural way to implement it. + +We then ran this, demonstrated +that it got the right answer + +on problems that were small +enough that we knew with the + +right answer was, ran it on a +big problem, got what we hoped + +was the right answer, but we had +no good way to check it in + +our heads, but noticed it +took a long time to run. + +And then we asked ourselves, +why did it + +take so long to run? + +And when we turned on the print +statement, what we saw + +is because it was doing +the same thing + +over and over again. + +Because we had a lot of the +sub-problems were the same. + +It was as if, when we went +through this search tree, we + +never remembered what we got +at the bottom, and we just + +re-computed things +over and over. + +So that led us to look at +memoization, the sort of key + +idea behind dynamic programming, +which says let's + +remember the work we've done and +not do it all over again. + +We used a dictionary to +implement the memo, and that + +got us to the fast max val, +which got called from max val + +0, because I wanted to make +sure I didn't change the + +specification of max val by +introducing this memo that + +users shouldn't know even +exists, because it's part of + +the implementation, not part +of the problem statement. + +We did that, and all I did was +take the original code and + +keep track of what I've done, +and say have I computed this + +value before, if so, don't +compute it again. + +And that's the key idea that +you'll see over and over again + +as you solve problems with +dynamic programming, is you + +say, have I already solved this +problem, if so, let me + +look up the answer. + +If I haven't solved the problem, +let me solve it, and + +store the answer away +for later reference. + +Very simple idea, and typically +the beauty of + +dynamic programming as you've +seen here, is not only is the + +idea simple, even the +implementation is simple. + +There are a lot of complicated +algorithmic ideas, dynamic + +programming is not +one of them. + +Which is one of the reasons +we teach it here. + +The other reason we teach it +here, in addition to it being + +simple, is that it's +incredibly useful. + +It's probably among the most +useful ideas there is for + +solving complicated problems. + +All right, now let's +look at it. + +So here's the fast version, we +looked at it last time, I'm + +not going to bore you by going +through the details of it + +again, but we'll run it. + +This was the big example we +looked at last time, where we + +had 30 items we could put in to +choose from, so when we do + +it exponentially, it looks like +it's 2 to the 30, which + +is a big number, but when we ran +this, it found the answer, + +and it took only 1805 calls. + +Now I got really excited about +this because, to me it's + +really amazing, that we've +taken a problem that is + +apparently exponential, and +solved it like that. + +And in fact, I could double +the size of the items to + +choose from, and it would +still run like. + +Eh - I'm not very good at +snapping my fingers -- it + +would still run quickly. + +All right, so here's the +question: have I found a way + +to solve an inherently +exponential + +problem in linear time. + +Because what we'll see here, +and we saw a little of this + +last time, as I double the +size of the items, I only + +really roughly double +the running time. + +Quite amazing. + +So have I done that? + +Well, I wish I had, because then +I would be really famous, + +and my department head would +give me a big raise, and all + +sorts of wonderful things +would follow. + +But, I'm not famous, and I +didn't solve that problem. + +What's going on? + +Well this particular algorithm +takes roughly, and I'll come + +back to the roughly question, +order (n,s) time, where n is + +the number of items in the list +and s, roughly speaking, + +is the size of the knapsack. + +We should also observe, that +it takes order and s space. + +Because it's not free to +store all these values. + +So at one level what I'm doing +is trading time for space. + +It can run faster because +I'm using some + +space to save things. + +So in this case, we had 30 items +and the wait was 40, + +and, you know, this gives +us 1200 which is + +kind of where we were. + +And I'm really emphasizing kind +of here, because really + +what I'm using the available +size for, is as a proxy for + +the number of items that can +fit in the knapsack. + +Because the actual running time +of this, and the actual + +space of this algorithm, is +governed, interestingly + +enough, not by the size of the +problem alone, but by the size + +of the solution. + +And I'm going to come +back to that. + +So how long it takes to run is +related to how many items I + +end up being able to fit +into the knapsack. + +If you think about it, +this make sense. + +An entry is made in the memo +whenever an item, and an + +available size pair +is considered. + +As soon as the available size +goes to 0, I know I can't + +enter any more items into +the memo, right? + +So the number of items I have to +remember is related to how + +many items I can fit +in the knapsack. + +And of course, the amount of +running time is exactly the + +number of things I +have to remember, + +almost exactly, right? + +So you can see if you think +about it abstractly, why the + +amount of work I have to do here +will be proportional to + +the number of items I can fit +in, that is to say, the size + +of the solution. + +This is not the way we'd like +to talk about complexity. + +When we talk about the order, +or big O, as we keep writing + +it, of a problem, we always +prefer to talk about it in + +terms of the size +of the problem. + +And that makes sense because in +general we don't know the + +size of the solution until +we've solved it. + +So we'd much rather define big +O in terms of the inputs. + +What we have here is +what's called a + +pseudo-polynomial algorithm. + +You remember a polynomial +algorithm is an algorithm + +that's polynomial in the +size of the inputs. + +Here we have an algorithm that's +polynomial in the size + +of the solution, hence +the qualifier pseudo. + +More formally, and again this is +not crucial to get all the + +details on this, if we think +about a numerical algorithm, a + +pseudo-polynomial algorithm +has running time that's + +polynomial in the numeric +value of the input. + +I'm using a numeric example +because it's easier to talk + +about it that way. + +So you might to look at, say, +an implementation of + +factorial, and say its running +time is proportional to the + +numerical value of the number +who's factorial. + +If I'm computing factorial of 8, +I'll do 8 operations, Right + +Factorial of 10, I'll +do 10 operations. + +Now the key issue to think about +here, is that as we look + +at this kind of thing, what +we'll see is that, if we look + +at a numeric value, we know that +that's exponential number + +in the number of digits. + +So that's the key thing to think +about, Right That you + +can take a problem, and +typically, when we're actually + +formally looking at +computational complexity, big + +O, what we'll define the in +terms of, is the size of the + +coding of the input. + +The number of bits required +to represent the + +input in the computer. + +And so when we say something is +exponential, we're talking + +about in terms of the number +of bits required + +to represent it. + +Now why am I going through all +this, maybe I should use the + +word pseudo-theory? + +Only because I want you to +understand that when we start + +talking about complexity, it +can be really quite subtle. + +And you have to be very careful +to think about what + +you mean, or you can be very +surprised at how long + +something takes to run, or +how much space it uses. + +And you have to understand the +difference between, are you + +defining the performance in +terms of the size of the + +problem, or the size +of the solution. + +When you talk about the size +of the problem, what do you + +mean by that, is it the length +of an array, is it the size of + +the elements of the array, +and it can matter. + +So when we ask you to tell +us something about the + +efficiency, on for example a +quiz, we want you to be very + +careful not to just write +something like, order n + +squared, but to tell +us what n is. + +For example, the number of +elements in the list. But if + +you have a list of lists, maybe +it's not just the number + +elements in the list, maybe +it depends upon what + +the elements are. + +So just sort of a warning to try +and be very careful as you + +think about these things, +all right. + +So I haven't done magic, I've +given you a really fast way to + +solve a knapsack problem, but +it's still exponential deep + +down in its heart, +in something. + +All right, in recitation you'll +get a chance to look at + +yet another kind of problem that +can be solved by dynamic + +programming, there +are many of them. + +Before we leave the knapsack +problem though, I want to take + +a couple of minutes to +look at a slight + +variation of the problem. + +So let's look at this one. + +Suppose I told you that not only +was there a limit on the + +total weight of the items +in the knapsack, + +but also on the volume. + +OK, if I gave you a box of +balloons, the fact that they + +didn't weight anything wouldn't +mean you couldn't + +put, you could put lots of them +in the knapsack, right? + +Sometimes it's the volume not +the weight that matters, + +sometimes it's both. + +So how would we go about solving +this problem if I told + +you not only was there a maximum +weight, but there was + +a maximum volume. + +Well, we want to go back and +attack it exactly the way we + +attacked it the first time, +which was write some + +mathematical formulas. + +So you'll remember that when we +looked at it, we said that + +the problem was to maximize the +sum from i equals 1 to n, + +of p sub i, x sub i, maybe it +should be 0 to n minus 1, but + +we won't worry about that. + +And we had to do it subject to +the constraint that the sum + +from 1 to n of the weight sub i +times x sub i, remember x is + +0 if it was in, 1 if it wasn't, +was less than or equal + +to the cost, as I wrote it +this time, which was the + +maximum allowable weight. + +What do we do if we want to +add volume, is an issue? + +Does this change? + +Does the goal change? + +You're answering. + +Answer out -- no one else can +see you shake your head. + +STUDENT: No. + +PROFESSOR: No. + +The goal does not change, it's +still the same goal. + +What changes? + +STUDENT: The constraints. + +PROFESSOR: Yeah, and you +don't get another bar. + +The constraint has to change. + +I've added a constraint. + +And, what's the constraint +I've added? + +Somebody else -- yeah? + +STUDENT: You can't exceed +the volume that the + +knapsack can hold. + +PROFESSOR: Right, but can +you state in this + +kind of formal way? + +STUDENT: [INAUDIBLE] + +PROFESSOR: -- sum from +i equals 1 to n -- + +STUDENT: [INAUDIBLE] + +PROFESSOR: Let's say v sub i, x +sub i, is less than or equal + +to, we'll write k for the +total allowable volume. + +Exactly. + +So the thing to notice here, +is it's actually quite a + +simple little change +we've made. + +I've simply added this one extra +constraint, nice thing + +about thinking about it this +way is it's easy to think + +about it, and what do you think +I'll have to do if I + +want to go change the code? + +I'm not going to do it for you, +but what would I think + +about doing when I +change the code? + +Well, let's look at the simple +version first, because it's + +easier to look at. + +At the top. + +Well basically, all I'd have to +do is go through and find + +every place I checked the +constraint, and change it. + +To incorporate the +new constraint. + +And when I went to the dynamic +programming problem, what + +would I have to do, +what would change? + +The memo would have to change, +as well as the checks, right? + +Because now, I not only would +have to think about how much + +weight did I have available, but +I have to think about how + +much volume did I +have available. + +So whereas before, I had a +mapping from the item and the + +weight available, now I would +have to have it from a tuple + +of the weight and the volume. + +Very small changes. + +That's one of the things I want +you to sort of understand + +as we look at algorithms, that +they're very general, and once + +you've figured out how to solve +one problem, you can + +often solve another problem +by a very straightforward + +reduction of this +kind of thing. + +All right, any questions +about that. + +Yeah? + +STUDENT: I had a question about +what you were talking + +about just before. + +PROFESSOR: The +pseudo-polynomial? + +STUDENT: Yes. + +PROFESSOR: Ok. + +STUDENT: So, how do you come +to a conclusion as to which + +you should use then, if you can +determine the size based + +on solution, or based on input, +so how do you decide? + +PROFESSOR: Great question. + +So the question is, how do you +choose an algorithm, why would + +I choose to use a +pseudo-polynomial algorithm + +when I don't know how big the +solution is likely to be, I + +think that's one way +to think about it. + +Well, so if we think about the +knapsack problem, we can look + +at it, and we can ask ourselves, +well first of all + +we know that the brute force +exponential solution is going + +to be a loser if the number +of items is large. + +Fundamentally in this case, what +I could look at is the + +ratio of the number of items to +the size of the knapsack, + +say well, I've got lots items +to choose from, I probably + +won't put them all in. + +But even if I did, it +would still only + +be 30 of them, right? + +It's hard. + +Typically what we'll discover +is the pseudo-polynomial + +algorithms are usually better, +and in this case, never worse. + +So this will never be worse than +the brute force one. if I + +get really unlucky, I end up +checking the same number of + +things, but I'd have to be +really, it'd have to be a very + +strange structure +to the problem. + +So it's almost always the case +that, if you can find a + +solution that uses dynamic +programming, it will be better + +than the brute force, and +certainly not, well, maybe use + +more space, but not +use more time. + +But there is no magic, here, and +so the question you asked + +is a very good question. + +And it's sometimes the case in +real life that you don't know + +which is the better algorithm +on the data you're actually + +going to be crunching. + +And you pays your money and you +takes your chances, right? + +And if the data is not what you +think it's going to be, + +you may be wrong in your choice, +so you typically do + +have to spend some time thinking +about it, what's the + +data going to actually +look like. + +Very good question. + +Anything else? + +All right, a couple of closing +points before we leave this, + +things I would like +you to remember. + +In dynamic programming, one of +the things that's going on is + +we're trading time for space. + +Dynamic programming is not +the only time we do that. + +We've solved a lot of problems +that way, in fact, by trading + +time for space. + +Table look-up, for example, +right, that if you're going to + +have trig tables, you may want +to compute them all at once + +and then just look it up. + +So that's one thing. + +Two, don't be intimidated by +exponential problems. There's + +a tendency for people to say, oh +this problem's exponential, + +I can't solve it. + +Well, I solve 2 or 3 exponential +problems before + +breakfast every day. + +You know things like, how to +find my way to the bathroom is + +inherently exponential, but I +manage to solve it anyway. + +Don't be intimidated. + +Even though it is apparently +exponential, a lot of times + +you can actually solve +it much, much faster. + +Other issues. + +Three: dynamic programming +is broadly useful. + +Whenever you're looking at a +problem that seems to have a + +natural recursive solution, +think about whether you can + +attack it with dynamic +programming. + +If you've got this optimal +substructure, and overlapping + +sub-problems, you can use +dynamic programming. + +So it's good for knapsacks, it's +good for shortest paths, + +it's good for change-making, +it's good for a whole variety + +of problems. And so keep it in +your toolbox, and when you + +have a hard problem to solve, +one of the first questions you + +should ask yourself is, can +I use dynamic programming? + +It's great for string-matching +problems of a whole variety. + +It's hugely useful. + +And finally, I want you to keep +in mind the whole concept + +of problem reduction. + +I started with this silly +description of a burglar, and + +said : Well this is really the +knapsack problem, and now I + +can go Google the knapsack +problem and find + +code to solve it. + +Any time you can reduce +something to a previously + +solved problem, that's good. + +And this is a hugely important +lesson to learn. + +People tend not to realize that +the first question you + +should always ask yourself, is +this really just something + +that's well-known in disguise? + +Is it a shortest path problem? + +Is it a nearest neighbor +problem? + +Is it what string is this +most similar to problem? + +There are scores of +well-understood problems, but + +only really scores, it's not +thousands of them, and over + +time you'll build up a +vocabulary of these problems, + +and when you see something in +your domain, be it physics or + +biology or anything else, +linguistics, the question you + +should ask is can I transform +this into an existing problem? + +Ok, double line. + +If there are no questions I'm +going to make a dramatic + +change in topic. + +We're going to temporarily get +off of this more esoteric + +stuff, and go back to Python. + +And for the next, off and on for +the next couple of weeks, + +we'll be talking about Python +and program organization. + +And what I want to be talking +about is modules of one sort, + +and of course that's because +what we're interested in is + +modularity. + +How do we take a complex +program, again, divide and + +conquer, I feel like a 1-trick +pony, I keep repeating the + +same thing over and +over again. + +Divide and conquer to make our +programs modular so we can + +write them a little piece at a +time and understand them a + +little piece at a time. + +Now I think of a module as a + +collection of related functions. + +We've already seen these, and +we're going to refer to the + +functions using dot notation. + +We've been doing this all +term, right, probably + +somewhere around lecture 2, we +said import math, and then + +somewhere in our program we +wrote something like math dot + +sqrt of 11, or some +other number. + +And the good news was we didn't +have to worry about how + +math did square root or anything +like that, we just + +got it and we used it. + +Now we have the dot notation +to avoid name conflicts. + +Imagine, for example, that in +my program I wrote something + +like import set, because +somebody had written a module + +that implements mathematical +sets, and somewhere else I'd + +written something like import +table, because someone had + +something that implemented +look-up tables of some sort, + +something like dictionaries, +for example. + +And then, I wanted to ask +something like membership. + +Is something in the set, or +is something in the table? + +Well, what I would have written +is something like + +table dot member. + +And then the element and +maybe the table. + +And the dot notation was used +to disambiguate, because I + +want the member operation +from table, not the + +member one from set. + +This was important because the +people who implemented table + +and set might never have met +each other, and so they can + +hardly have been expected not +to have used the same name + +somewhere by accident. + +Hence the use of the +dot notation. + +I now want to talk about a +particular kind of module, and + +those are the modules +that include + +classes or that are classes. + +This is a very important concept +as we'll see, it's why + +MIT calls things like 6.00 +subjects, so that they don't + +get confused with classes in +Python, something we really + +need to remember here. + +Now they can be used in +different ways, and they have + +been historically used +in different ways. + +In this subject we're going to +emphasize using classes in the + +context of what's called +object-oriented programming. + +And if you go look up at Python +books on the web, or + +Java books on the web, about 80% +of them will include the + +word object-oriented +in their title. + +Object-oriented Python +programming for computer + +games, or who knows what else. + +And we're going to use this +object-oriented programming, + +typically to create something +called data abstractions. + +And over the next couple of +days, you'll see what we mean + +by this in detail. + +A synonym for this is an +abstract data type. + +You'll see both terms used on +the web, and the literature + +etc., and think of them as +synonyms. Now these ideas of + +classes, object-oriented +programming, data abstraction, + +are about 40 years old, +they're not new ideas. + +But they've only been really +widely accepted in practice + +for 10 to 15 years. + +It was in the mid-70's, people +began to write articles + +advocating this style of +programming, and actually + +building programming languages, +notably Smalltalk + +and Clue at MIT in fact, that +provided linguistic support + +for the ideas of data +abstraction and + +object-oriented programming. + +But it really wasn't until, I +would say, the arrival of Java + +that object-oriented +programming + +caught the popular attention. + +And then Java, C++ , +Python of, course. + +And today nobody advocates a +programming language that does + +not support it in some +sort of way. + +So what is this all about? + +What is an object in +object-oriented programming? + +An object is a collection +of data and functions. + +In particular functions that +operate on the data, perhaps + +on other data as well. + +The key idea here is to bind +together the data and the + +functions that operate on that +data as a single thing. + +Now typically that's probably +not the way you've been + +thinking about things. + +When you think about an int or +a float or a dictionary or a + +list, you knew that there +were functions + +that operated on them. + +But when you pass a parameter +say, a list, you didn't think + +that you were not only passing +the list, you were also + +passing the functions +that operate on the + +list. In fact you are. + +It often doesn't matter, but +it sometimes really does. + +The advantage of that, is that +when you pass an object to + +another part of the program, +that part of the program also + +gets the ability to perform +operations on the object. + +Now when the only types we're +dealing with are the built-in + +types, the ones that came with +the programming language, that + +doesn't really matter. + +Because, well, the programming +language means everybody has + +access to those operations. + +But the key idea here is that +we're going to be generating + +user-defined types, we'll invent +new types, and as we do + +that we can't assume that if +as we pass objects of that + +type around, that the +programming language is giving + +us the appropriate operations +on that type. + +This combining of data and +functions on that data is a + +very essence of object-oriented +programming. + +That's really what defines it. + +And the word that's often used +for that is encapsulation. + +Think of it as we got a capsule, +like a pill or + +something, and in that capsule +we've got data and a bunch of + +functions, which as we'll +see are called methods. + +Don't worry, it doesn't matter +that they're called methods, + +it's a historical artifact. + +All right, so what's +an example of this? + +Well, we could create a circle +object, that would store a + +representation of the circle +and also provide methods to + +operate on it, for example, draw +the circle on the screen, + +return the area of the circle, +inscribe it in a square, who + +knows what you want +to do with it. + +As we talk about this, as people +talk about this, in the + +context of our object-oriented +programming, they typically + +will talk about it in terms +of message pass, a message + +passing metaphor. + +I want to mention it's just +a metaphor, just a way of + +thinking about it, it's not +anything very deep here. + +So, the way people will talk +about this, is one object can + +pass a message to another +object, and the receiving + +object responds by executing +one of its + +methods on the object. + +So let's think about lists. + +So if l is a list, I can +call something like s + +dot sort, l dot sort. + +You've seen this. + +This says, pass the object l +the message sort, and that + +message says find the method +sort, and apply it to the + +object l, in this case mutating +the object so that + +the elements are now +in sorted order. + +If c is a circle, I might write + +something like c dot area. + +And this would say, pass to +the object denoted by the + +variable c, the message area, +which says execute a method + +called area, and in this case +the method might return a + +float, rather than have +a side-effect. + +Now again, don't get carried +away, I almost didn't talk + +about this whole message-passing +paradigm, but + +it's so pervasive in the +world I felt you needed + +to hear about it. + +But it's nothing very deep, and +if you want to not think + +about messages, and just think +oh, c has a method area, a + +circle has a method area, and +c as a circle will apply it + +and do what it says, you won't +get in any trouble at all. + +Now the next concept to think +about here, is the notion of + +an instance. + +So we've already thought about, +we create instances of + +types, so when we looked at +lists, and we looked at the + +notion of aliasing, we used the +word instance, and said + +this is 1 object, this is +another object, each of those + +objects is an instance of +type list. So now that + +gets us to a class. + +A class is a collection +of objects with + +characteristics in common. + +So you can think of class +list. What is the + +characteristic that all objects +of class list have in + +common, all instances of class +list? it's the set of methods + +that can be applied to lists. + +Methods like sort, append, +other things. + +So you should think of all of +the built-in types we've + +talked about as actually just +built-in classes, like + +dictionaries, lists, etc. + +The beauty of being able to +define your own class is you + +can now extend the language. + +So if, for example, you're in +the business, God forbid, of + +writing financial software +today, you might decide, I'd + +really like to have a class +called tanking stock, or bad + +mortgage, or something like +that or mortgage, right? + +Which would have a bunch of +operations, like, I won't go + +into what they might be. + +But you'd like to write your +program not in terms of floats + +and ints and lists, but in terms +of mortgages, and CDOs, + +and all of the objects that you +read about in the paper, + +the types you read about. + +And so you get to build your +own special purpose + +programming language that helped +you solve your problems + +in biology or finance or +whatever, and we'll pick up + +here again on Tuesday. \ No newline at end of file diff --git a/lm8ywGl9AIQ.txt b/lm8ywGl9AIQ.txt new file mode 100644 index 0000000000000000000000000000000000000000..7a387f3090f7a620a1e680c1985ac5de376a15d5 --- /dev/null +++ b/lm8ywGl9AIQ.txt @@ -0,0 +1,7475 @@ +align:start position:0% + +I'm a professor in the biology + + align:start position:0% +I'm a professor in the biology + + + align:start position:0% +I'm a professor in the biology +department at MIT and I will be + + align:start position:0% +department at MIT and I will be + + + align:start position:0% +department at MIT and I will be +co-teaching this course with uh Penny + + align:start position:0% +co-teaching this course with uh Penny + + + align:start position:0% +co-teaching this course with uh Penny +Chisum who's a professor in the + + align:start position:0% +Chisum who's a professor in the + + + align:start position:0% +Chisum who's a professor in the +Department of Civil and environmental + + align:start position:0% +Department of Civil and environmental + + + align:start position:0% +Department of Civil and environmental +engineering as well as a a professor in + + align:start position:0% +engineering as well as a a professor in + + + align:start position:0% +engineering as well as a a professor in +biology Department as well uh Penny was + + align:start position:0% +biology Department as well uh Penny was + + + align:start position:0% +biology Department as well uh Penny was +recently featured in the uh journal + + align:start position:0% +recently featured in the uh journal + + + align:start position:0% +recently featured in the uh journal +Nature uh she's a very well-known um + + align:start position:0% +Nature uh she's a very well-known um + + + align:start position:0% +Nature uh she's a very well-known um +ocean oceanographer who's become + + align:start position:0% +ocean oceanographer who's become + + + align:start position:0% +ocean oceanographer who's become +deservedly famous for discovering a very + + align:start position:0% +deservedly famous for discovering a very + + + align:start position:0% +deservedly famous for discovering a very +small bacterium that's capable of + + align:start position:0% +small bacterium that's capable of + + + align:start position:0% +small bacterium that's capable of +carrying out photosynthesis uh for many + + align:start position:0% +carrying out photosynthesis uh for many + + + align:start position:0% +carrying out photosynthesis uh for many +years oceanographers used filters the + + align:start position:0% +years oceanographers used filters the + + + align:start position:0% +years oceanographers used filters the +holes were big enough that this + + align:start position:0% +holes were big enough that this + + + align:start position:0% +holes were big enough that this +bacterium went through and so when they + + align:start position:0% +bacterium went through and so when they + + + align:start position:0% +bacterium went through and so when they +were doing their studies of the ocean + + align:start position:0% +were doing their studies of the ocean + + + align:start position:0% +were doing their studies of the ocean +and how the the biomass that was there + + align:start position:0% +and how the the biomass that was there + + + align:start position:0% +and how the the biomass that was there +and all the fluxes and so on they didn't + + align:start position:0% +and all the fluxes and so on they didn't + + + align:start position:0% +and all the fluxes and so on they didn't +know this organism existed which can + + align:start position:0% +know this organism existed which can + + + align:start position:0% +know this organism existed which can +form up to 50% of the biomass in in + + align:start position:0% +form up to 50% of the biomass in in + + + align:start position:0% +form up to 50% of the biomass in in +parts of the ocean so um Penny's really + + align:start position:0% +parts of the ocean so um Penny's really + + + align:start position:0% +parts of the ocean so um Penny's really +a wonderful lecture a wonderful person + + align:start position:0% +a wonderful lecture a wonderful person + + + align:start position:0% +a wonderful lecture a wonderful person +and she'll be talking teaching the + + align:start position:0% +and she'll be talking teaching the + + + align:start position:0% +and she'll be talking teaching the +component of + + align:start position:0% +component of + + + align:start position:0% +component of +7014 which deals with ecology in the + + align:start position:0% +7014 which deals with ecology in the + + + align:start position:0% +7014 which deals with ecology in the +environment and this is a a section of + + align:start position:0% +environment and this is a a section of + + + align:start position:0% +environment and this is a a section of +7014 that uh is makes it different from + + align:start position:0% +7014 that uh is makes it different from + + + align:start position:0% +7014 that uh is makes it different from +the other two versions 712 and + + align:start position:0% +the other two versions 712 and + + + align:start position:0% +the other two versions 712 and +7013 so for me uh personally this is uh + + align:start position:0% +7013 so for me uh personally this is uh + + + align:start position:0% +7013 so for me uh personally this is uh +an absolutely wonderful uh exciting + + align:start position:0% +an absolutely wonderful uh exciting + + + align:start position:0% +an absolutely wonderful uh exciting +opportunity to be able to teach this + + align:start position:0% +opportunity to be able to teach this + + + align:start position:0% +opportunity to be able to teach this +introductory biology course + + align:start position:0% +introductory biology course + + + align:start position:0% +introductory biology course +uh for some of you I know that biology + + align:start position:0% +uh for some of you I know that biology + + + align:start position:0% +uh for some of you I know that biology +is going to either be a major part of + + align:start position:0% +is going to either be a major part of + + + align:start position:0% +is going to either be a major part of +your career or quite possibly even if + + align:start position:0% +your career or quite possibly even if + + + align:start position:0% +your career or quite possibly even if +you're in engineering or something else + + align:start position:0% +you're in engineering or something else + + + align:start position:0% +you're in engineering or something else +you will find yourselves working with a + + align:start position:0% +you will find yourselves working with a + + + align:start position:0% +you will find yourselves working with a +biological system you can see that + + align:start position:0% +biological system you can see that + + + align:start position:0% +biological system you can see that +happening all over campus these days + + align:start position:0% +happening all over campus these days + + + align:start position:0% +happening all over campus these days +that more and more engineering + + align:start position:0% +that more and more engineering + + + align:start position:0% +that more and more engineering +departments are finding that they're + + align:start position:0% +departments are finding that they're + + + align:start position:0% +departments are finding that they're +working on problems that come from + + align:start position:0% +working on problems that come from + + + align:start position:0% +working on problems that come from +biology or have a biological + + align:start position:0% +biology or have a biological + + + align:start position:0% +biology or have a biological +component um there I'm sure there are at + + align:start position:0% +component um there I'm sure there are at + + + align:start position:0% +component um there I'm sure there are at +least a few of you here who are only + + align:start position:0% +least a few of you here who are only + + + align:start position:0% +least a few of you here who are only +here because it's a a uh required course + + align:start position:0% +here because it's a a uh required course + + + align:start position:0% +here because it's a a uh required course +and you might well wish you were were + + align:start position:0% +and you might well wish you were were + + + align:start position:0% +and you might well wish you were were +somewhere else however I will do my best + + align:start position:0% +somewhere else however I will do my best + + + align:start position:0% +somewhere else however I will do my best +to try to communicate to you why you + + align:start position:0% +to try to communicate to you why you + + + align:start position:0% +to try to communicate to you why you +need to know some biology too I think + + align:start position:0% +need to know some biology too I think + + + align:start position:0% +need to know some biology too I think +most of you know you can hardly pick up + + align:start position:0% +most of you know you can hardly pick up + + + align:start position:0% +most of you know you can hardly pick up +a newspaper uh these days without + + align:start position:0% +a newspaper uh these days without + + + align:start position:0% +a newspaper uh these days without +running into something uh that Demands a + + align:start position:0% +running into something uh that Demands a + + + align:start position:0% +running into something uh that Demands a +a knowledge of biology something about + + align:start position:0% +a knowledge of biology something about + + + align:start position:0% +a knowledge of biology something about +stem cells something about cloning + + align:start position:0% +stem cells something about cloning + + + align:start position:0% +stem cells something about cloning +humans something about a a new drug uh + + align:start position:0% +humans something about a a new drug uh + + + align:start position:0% +humans something about a a new drug uh +lots of things having to do with uh + + align:start position:0% +lots of things having to do with uh + + + align:start position:0% +lots of things having to do with uh +biological effects on the uh on the + + align:start position:0% +biological effects on the uh on the + + + align:start position:0% +biological effects on the uh on the +environment and so on uh you're also + + align:start position:0% +environment and so on uh you're also + + + align:start position:0% +environment and so on uh you're also +going to be confronted with uh decisions + + align:start position:0% +going to be confronted with uh decisions + + + align:start position:0% +going to be confronted with uh decisions +about your health about the health of + + align:start position:0% +about your health about the health of + + + align:start position:0% +about your health about the health of +your loved ones concerning cancer + + align:start position:0% +your loved ones concerning cancer + + + align:start position:0% +your loved ones concerning cancer +concerning uh whether child uh might + + align:start position:0% +concerning uh whether child uh might + + + align:start position:0% +concerning uh whether child uh might +have birth effects all sorts of issues + + align:start position:0% +have birth effects all sorts of issues + + + align:start position:0% +have birth effects all sorts of issues +that will affect your personal lives + + align:start position:0% +that will affect your personal lives + + + align:start position:0% +that will affect your personal lives +that demand an understanding of biology + + align:start position:0% +that demand an understanding of biology + + + align:start position:0% +that demand an understanding of biology +so I feel with some passion that whether + + align:start position:0% +so I feel with some passion that whether + + + align:start position:0% +so I feel with some passion that whether +you're you think you're going to need + + align:start position:0% +you're you think you're going to need + + + align:start position:0% +you're you think you're going to need +biology in your professional career or + + align:start position:0% +biology in your professional career or + + + align:start position:0% +biology in your professional career or +not everyone in this uh institution + + align:start position:0% +not everyone in this uh institution + + + align:start position:0% +not everyone in this uh institution +needs some understanding of biology uh + + align:start position:0% +needs some understanding of biology uh + + + align:start position:0% +needs some understanding of biology uh +to just live their ordinary lives I also + + align:start position:0% +to just live their ordinary lives I also + + + align:start position:0% +to just live their ordinary lives I also +think when as MIT students you're going + + align:start position:0% +think when as MIT students you're going + + + align:start position:0% +think when as MIT students you're going +to be looked at uh as you go through + + align:start position:0% +to be looked at uh as you go through + + + align:start position:0% +to be looked at uh as you go through +your lives as people who are + + align:start position:0% +your lives as people who are + + + align:start position:0% +your lives as people who are +knowledgeable about science and uh and + + align:start position:0% +knowledgeable about science and uh and + + + align:start position:0% +knowledgeable about science and uh and +engineering and you'll be asked + + align:start position:0% +engineering and you'll be asked + + + align:start position:0% +engineering and you'll be asked +questions go far beyond your immediate + + align:start position:0% +questions go far beyond your immediate + + + align:start position:0% +questions go far beyond your immediate +area of expertise and again I think it's + + align:start position:0% +area of expertise and again I think it's + + + align:start position:0% +area of expertise and again I think it's +another reason for needing to know uh + + align:start position:0% +another reason for needing to know uh + + + align:start position:0% +another reason for needing to know uh +some of biology anyway um it's an + + align:start position:0% +some of biology anyway um it's an + + + align:start position:0% +some of biology anyway um it's an +absolutely wonderful time to teach + + align:start position:0% +absolutely wonderful time to teach + + + align:start position:0% +absolutely wonderful time to teach +biology because it's things have just + + align:start position:0% +biology because it's things have just + + + align:start position:0% +biology because it's things have just +been exploding over the last two or + + align:start position:0% +been exploding over the last two or + + + align:start position:0% +been exploding over the last two or +three decades and things are moving + + align:start position:0% +three decades and things are moving + + + align:start position:0% +three decades and things are moving +faster than ever and another wonderful + + align:start position:0% +faster than ever and another wonderful + + + align:start position:0% +faster than ever and another wonderful +thing about teaching biology is that MIT + + align:start position:0% +thing about teaching biology is that MIT + + + align:start position:0% +thing about teaching biology is that MIT +is an absolutely marvelous place to + + align:start position:0% +is an absolutely marvelous place to + + + align:start position:0% +is an absolutely marvelous place to +teach it just to sort of drive this home + + align:start position:0% +teach it just to sort of drive this home + + + align:start position:0% +teach it just to sort of drive this home +in the biology Department alone there + + align:start position:0% +in the biology Department alone there + + + align:start position:0% +in the biology Department alone there +are four Nobel laurates who made got + + align:start position:0% +are four Nobel laurates who made got + + + align:start position:0% +are four Nobel laurates who made got +honored for critical discoveries in + + align:start position:0% +honored for critical discoveries in + + + align:start position:0% +honored for critical discoveries in +biology Goin kurana who's just down the + + align:start position:0% +biology Goin kurana who's just down the + + + align:start position:0% +biology Goin kurana who's just down the +hall from me uh synthesized the first + + align:start position:0% +hall from me uh synthesized the first + + + align:start position:0% +hall from me uh synthesized the first +Gene was a extraordinary feat of + + align:start position:0% +Gene was a extraordinary feat of + + + align:start position:0% +Gene was a extraordinary feat of +synthesis of of organic chemistry + + align:start position:0% +synthesis of of organic chemistry + + + align:start position:0% +synthesis of of organic chemistry +synthesizing DNA when I was an undergrad + + align:start position:0% +synthesizing DNA when I was an undergrad + + + align:start position:0% +synthesizing DNA when I was an undergrad +I I had was a chemistry major um but + + align:start position:0% +I I had was a chemistry major um but + + + align:start position:0% +I I had was a chemistry major um but +I had to take an introductory biology + + align:start position:0% +I had to take an introductory biology + + + align:start position:0% +I had to take an introductory biology +course and at that point the DNA wasn't + + align:start position:0% +course and at that point the DNA wasn't + + + align:start position:0% +course and at that point the DNA wasn't +mentioned in the high school um courses + + align:start position:0% +mentioned in the high school um courses + + + align:start position:0% +mentioned in the high school um courses +so the first time that I heard about DNA + + align:start position:0% +so the first time that I heard about DNA + + + align:start position:0% +so the first time that I heard about DNA +was in my introductory biology course + + align:start position:0% +was in my introductory biology course + + + align:start position:0% +was in my introductory biology course +and that uh determined my career + + align:start position:0% +and that uh determined my career + + + align:start position:0% +and that uh determined my career +Direction I thought that was such a an + + align:start position:0% +Direction I thought that was such a an + + + align:start position:0% +Direction I thought that was such a an +interesting molecule that I wanted to + + align:start position:0% +interesting molecule that I wanted to + + + align:start position:0% +interesting molecule that I wanted to +work on it and I tucked myself into one + + align:start position:0% +work on it and I tucked myself into one + + + align:start position:0% +work on it and I tucked myself into one +of the labs in Ottawa Canada where I + + align:start position:0% +of the labs in Ottawa Canada where I + + + align:start position:0% +of the labs in Ottawa Canada where I +grew up that was trying to synthesize + + align:start position:0% +grew up that was trying to synthesize + + + align:start position:0% +grew up that was trying to synthesize +DNA synthesize pieces of a gene and as I + + align:start position:0% +DNA synthesize pieces of a gene and as I + + + align:start position:0% +DNA synthesize pieces of a gene and as I +turned out later competing + + align:start position:0% +turned out later competing + + + align:start position:0% +turned out later competing +unsuccessfully with my now colleague + + align:start position:0% +unsuccessfully with my now colleague + + + align:start position:0% +unsuccessfully with my now colleague +Goen + + align:start position:0% +Goen + + + align:start position:0% +Goen +Karana uh suumo tagawa uh got a Nobel + + align:start position:0% +Karana uh suumo tagawa uh got a Nobel + + + align:start position:0% +Karana uh suumo tagawa uh got a Nobel +Prize for discovering the amazing + + align:start position:0% +Prize for discovering the amazing + + + align:start position:0% +Prize for discovering the amazing +molecular uh operations that underly the + + align:start position:0% +molecular uh operations that underly the + + + align:start position:0% +molecular uh operations that underly the +diversity of the immune system your + + align:start position:0% +diversity of the immune system your + + + align:start position:0% +diversity of the immune system your +immune system has a capacity to + + align:start position:0% +immune system has a capacity to + + + align:start position:0% +immune system has a capacity to +recognize um viruses and uh bacteria all + + align:start position:0% +recognize um viruses and uh bacteria all + + + align:start position:0% +recognize um viruses and uh bacteria all +sorts of different pathogens and + + align:start position:0% +sorts of different pathogens and + + + align:start position:0% +sorts of different pathogens and +including molecules it can recognize + + align:start position:0% +including molecules it can recognize + + + align:start position:0% +including molecules it can recognize +molecules that haven't even ever been + + align:start position:0% +molecules that haven't even ever been + + + align:start position:0% +molecules that haven't even ever been +synthesized in history + + align:start position:0% +synthesized in history + + + align:start position:0% +synthesized in history +of life and we'll talk towards the end + + align:start position:0% +of life and we'll talk towards the end + + + align:start position:0% +of life and we'll talk towards the end +of the course about the way that happens + + align:start position:0% +of the course about the way that happens + + + align:start position:0% +of the course about the way that happens +and you'll see why susumo got his Nobel + + align:start position:0% +and you'll see why susumo got his Nobel + + + align:start position:0% +and you'll see why susumo got his Nobel +Prize um Phil sharp got his for + + align:start position:0% +Prize um Phil sharp got his for + + + align:start position:0% +Prize um Phil sharp got his for +discovering RNA splicing a completely + + align:start position:0% +discovering RNA splicing a completely + + + align:start position:0% +discovering RNA splicing a completely +unanticipated component of the very + + align:start position:0% +unanticipated component of the very + + + align:start position:0% +unanticipated component of the very +heart of of uh molecular biology and + + align:start position:0% +heart of of uh molecular biology and + + + align:start position:0% +heart of of uh molecular biology and +then Bob horvitz who's a peer of mine we + + align:start position:0% +then Bob horvitz who's a peer of mine we + + + align:start position:0% +then Bob horvitz who's a peer of mine we +started at MIT at the same time and our + + align:start position:0% +started at MIT at the same time and our + + + align:start position:0% +started at MIT at the same time and our +our Labs were side by side for many + + align:start position:0% +our Labs were side by side for many + + + align:start position:0% +our Labs were side by side for many +years got his Nobel 200 for discovering + + align:start position:0% +years got his Nobel 200 for discovering + + + align:start position:0% +years got his Nobel 200 for discovering +a phenomena the general term is uh + + align:start position:0% +a phenomena the general term is uh + + + align:start position:0% +a phenomena the general term is uh +program cell death and it plays all + + align:start position:0% +program cell death and it plays all + + + align:start position:0% +program cell death and it plays all +sorts of important roles in biology from + + align:start position:0% +sorts of important roles in biology from + + + align:start position:0% +sorts of important roles in biology from +scul sculpting the shapes of organs and + + align:start position:0% +scul sculpting the shapes of organs and + + + align:start position:0% +scul sculpting the shapes of organs and +tissues we initially have webs when + + align:start position:0% +tissues we initially have webs when + + + align:start position:0% +tissues we initially have webs when +we're developing between our fingers and + + align:start position:0% +we're developing between our fingers and + + + align:start position:0% +we're developing between our fingers and +those go away because of a kind of + + align:start position:0% +those go away because of a kind of + + + align:start position:0% +those go away because of a kind of +programed cell death that the cells that + + align:start position:0% +programed cell death that the cells that + + + align:start position:0% +programed cell death that the cells that +were making the web disappear uh and + + align:start position:0% +were making the web disappear uh and + + + align:start position:0% +were making the web disappear uh and +another role of that is to prevent + + align:start position:0% +another role of that is to prevent + + + align:start position:0% +another role of that is to prevent +cancer that if cells sense that + + align:start position:0% +cancer that if cells sense that + + + align:start position:0% +cancer that if cells sense that +something is very messed up they have a + + align:start position:0% +something is very messed up they have a + + + align:start position:0% +something is very messed up they have a +sort of suicide program that would uh + + align:start position:0% +sort of suicide program that would uh + + + align:start position:0% +sort of suicide program that would uh +make them destroy themselves and if that + + align:start position:0% +make them destroy themselves and if that + + + align:start position:0% +make them destroy themselves and if that +doesn't happen those could go on and + + align:start position:0% +doesn't happen those could go on and + + + align:start position:0% +doesn't happen those could go on and +become more and more abnormal and + + align:start position:0% +become more and more abnormal and + + + align:start position:0% +become more and more abnormal and +eventually uh turn into uh an invasive + + align:start position:0% +eventually uh turn into uh an invasive + + + align:start position:0% +eventually uh turn into uh an invasive +cancer anyway uh there's a picture of + + align:start position:0% +cancer anyway uh there's a picture of + + + align:start position:0% +cancer anyway uh there's a picture of +Bob uh when we was The Institute was + + align:start position:0% +Bob uh when we was The Institute was + + + align:start position:0% +Bob uh when we was The Institute was +celebrating his um his Nobel Prize he + + align:start position:0% +celebrating his um his Nobel Prize he + + + align:start position:0% +celebrating his um his Nobel Prize he +getting a congratulatory kiss from artha + + align:start position:0% +getting a congratulatory kiss from artha + + + align:start position:0% +getting a congratulatory kiss from artha +Constantine Patton also a professor in + + align:start position:0% +Constantine Patton also a professor in + + + align:start position:0% +Constantine Patton also a professor in +biology Department who happens to be uh + + align:start position:0% +biology Department who happens to be uh + + + align:start position:0% +biology Department who happens to be uh +Bob's wife um most of you know that the + + align:start position:0% +Bob's wife um most of you know that the + + + align:start position:0% +Bob's wife um most of you know that the +human genome has now been sequenced that + + align:start position:0% +human genome has now been sequenced that + + + align:start position:0% +human genome has now been sequenced that +was one of the huge undertakings in most + + align:start position:0% +was one of the huge undertakings in most + + + align:start position:0% +was one of the huge undertakings in most +important undertakings in Modern Biology + + align:start position:0% +important undertakings in Modern Biology + + + align:start position:0% +important undertakings in Modern Biology +over the last while uh it was an + + align:start position:0% +over the last while uh it was an + + + align:start position:0% +over the last while uh it was an +incredible feat each cell has uh as you + + align:start position:0% +incredible feat each cell has uh as you + + + align:start position:0% +incredible feat each cell has uh as you +mostly most of you know 46 chromosomes + + align:start position:0% +mostly most of you know 46 chromosomes + + + align:start position:0% +mostly most of you know 46 chromosomes +that's a total of about 2 meters of DNA + + align:start position:0% +that's a total of about 2 meters of DNA + + + align:start position:0% +that's a total of about 2 meters of DNA +in every human cell and that 2 meters of + + align:start position:0% +in every human cell and that 2 meters of + + + align:start position:0% +in every human cell and that 2 meters of +is composed of about 3 million DNA base + + align:start position:0% +is composed of about 3 million DNA base + + + align:start position:0% +is composed of about 3 million DNA base +pairs these letters A and C that we'll + + align:start position:0% +pairs these letters A and C that we'll + + + align:start position:0% +pairs these letters A and C that we'll +be talking about as we go through the + + align:start position:0% +be talking about as we go through the + + + align:start position:0% +be talking about as we go through the +through the course so to sequence The + + align:start position:0% +through the course so to sequence The + + + align:start position:0% +through the course so to sequence The +genome had to work out the sequence of + + align:start position:0% +genome had to work out the sequence of + + + align:start position:0% +genome had to work out the sequence of +these the exact run of these AGT CS + + align:start position:0% +these the exact run of these AGT CS + + + align:start position:0% +these the exact run of these AGT CS +along the backbone for three uh billion + + align:start position:0% +along the backbone for three uh billion + + + align:start position:0% +along the backbone for three uh billion +uh um base pairs and somewhere that + + align:start position:0% +uh um base pairs and somewhere that + + + align:start position:0% +uh um base pairs and somewhere that +genome encodes somewhere between 20 and + + align:start position:0% +genome encodes somewhere between 20 and + + + align:start position:0% +genome encodes somewhere between 20 and +30,000 genes and we'll be talking about + + align:start position:0% +30,000 genes and we'll be talking about + + + align:start position:0% +30,000 genes and we'll be talking about +the the proteins that are encoded by + + align:start position:0% +the the proteins that are encoded by + + + align:start position:0% +the the proteins that are encoded by +most of those genes and their important + + align:start position:0% +most of those genes and their important + + + align:start position:0% +most of those genes and their important +roles as we go on in the um course what + + align:start position:0% +roles as we go on in the um course what + + + align:start position:0% +roles as we go on in the um course what +some of you may not know is the key role + + align:start position:0% +some of you may not know is the key role + + + align:start position:0% +some of you may not know is the key role +that M uh played in this about a third + + align:start position:0% +that M uh played in this about a third + + + align:start position:0% +that M uh played in this about a third +of the genome was sequenced at the uh + + align:start position:0% +of the genome was sequenced at the uh + + + align:start position:0% +of the genome was sequenced at the uh +the Whitehead uh MIT genome Center and + + align:start position:0% +the Whitehead uh MIT genome Center and + + + align:start position:0% +the Whitehead uh MIT genome Center and +here's some of the robots that were used + + align:start position:0% +here's some of the robots that were used + + + align:start position:0% +here's some of the robots that were used +to sequence that DNA and that sequencing + + align:start position:0% +to sequence that DNA and that sequencing + + + align:start position:0% +to sequence that DNA and that sequencing +effort was led by Eric Lander whose name + + align:start position:0% +effort was led by Eric Lander whose name + + + align:start position:0% +effort was led by Eric Lander whose name +some of you may recognize because he + + align:start position:0% +some of you may recognize because he + + + align:start position:0% +some of you may recognize because he +teaches the fall version of 701 along + + align:start position:0% +teaches the fall version of 701 along + + + align:start position:0% +teaches the fall version of 701 along +with uh Bob + + align:start position:0% + + + + align:start position:0% + +Weinberg so here just a few examples of + + align:start position:0% +Weinberg so here just a few examples of + + + align:start position:0% +Weinberg so here just a few examples of +why uh I think it's important for you to + + align:start position:0% +why uh I think it's important for you to + + + align:start position:0% +why uh I think it's important for you to +understand uh biology regardless of + + align:start position:0% +understand uh biology regardless of + + + align:start position:0% +understand uh biology regardless of +whether you're uh going to go on and use + + align:start position:0% +whether you're uh going to go on and use + + + align:start position:0% +whether you're uh going to go on and use +it professionally most of you know one + + align:start position:0% +it professionally most of you know one + + + align:start position:0% +it professionally most of you know one +of the biggest challenges we face as + + align:start position:0% +of the biggest challenges we face as + + + align:start position:0% +of the biggest challenges we face as +this planet is this Aid AIDS uh epidemic + + align:start position:0% +this planet is this Aid AIDS uh epidemic + + + align:start position:0% +this planet is this Aid AIDS uh epidemic +it's caused by a certain kind of virus + + align:start position:0% +it's caused by a certain kind of virus + + + align:start position:0% +it's caused by a certain kind of virus +called + + align:start position:0% +called + + + align:start position:0% +called +hiv1 that gets into particular cells of + + align:start position:0% +hiv1 that gets into particular cells of + + + align:start position:0% +hiv1 that gets into particular cells of +your immune system that defend normally + + align:start position:0% +your immune system that defend normally + + + align:start position:0% +your immune system that defend normally +defends us against infection and + + align:start position:0% +defends us against infection and + + + align:start position:0% +defends us against infection and +destroys those and um then people die + + align:start position:0% +destroys those and um then people die + + + align:start position:0% +destroys those and um then people die +from infections by other organisms that + + align:start position:0% +from infections by other organisms that + + + align:start position:0% +from infections by other organisms that +normally you can fight off it's a huge + + align:start position:0% +normally you can fight off it's a huge + + + align:start position:0% +normally you can fight off it's a huge +problem with societ vast societal and + + align:start position:0% +problem with societ vast societal and + + + align:start position:0% +problem with societ vast societal and +economic uh implications and it's one + + align:start position:0% +economic uh implications and it's one + + + align:start position:0% +economic uh implications and it's one +that we're still as a as a mankind still + + align:start position:0% +that we're still as a as a mankind still + + + align:start position:0% +that we're still as a as a mankind still +trying to to deal with grapple with uh + + align:start position:0% +trying to to deal with grapple with uh + + + align:start position:0% +trying to to deal with grapple with uh +here's another example just a couple of + + align:start position:0% +here's another example just a couple of + + + align:start position:0% +here's another example just a couple of +years ago there was the scare of Anthrax + + align:start position:0% +years ago there was the scare of Anthrax + + + align:start position:0% +years ago there was the scare of Anthrax +it's a bacterium that's very pathogenic + + align:start position:0% +it's a bacterium that's very pathogenic + + + align:start position:0% +it's a bacterium that's very pathogenic +can kill its host fairly easily does it + + align:start position:0% +can kill its host fairly easily does it + + + align:start position:0% +can kill its host fairly easily does it +by making uh particular toxins this the + + align:start position:0% +by making uh particular toxins this the + + + align:start position:0% +by making uh particular toxins this the +details shown here don't matter but just + + align:start position:0% +details shown here don't matter but just + + + align:start position:0% +details shown here don't matter but just +reminding you that this is something + + align:start position:0% +reminding you that this is something + + + align:start position:0% +reminding you that this is something +that was in the front pages of the paper + + align:start position:0% +that was in the front pages of the paper + + + align:start position:0% +that was in the front pages of the paper +just a little while ago + + align:start position:0% +just a little while ago + + + align:start position:0% +just a little while ago +um couple of years ago when I was + + align:start position:0% +um couple of years ago when I was + + + align:start position:0% +um couple of years ago when I was +teaching this we had the scare with the + + align:start position:0% +teaching this we had the scare with the + + + align:start position:0% +teaching this we had the scare with the +scar SARS virus that went all the way + + align:start position:0% +scar SARS virus that went all the way + + + align:start position:0% +scar SARS virus that went all the way +during the course when I was teaching it + + align:start position:0% +during the course when I was teaching it + + + align:start position:0% +during the course when I was teaching it +from the initial discovery of the virus + + align:start position:0% +from the initial discovery of the virus + + + align:start position:0% +from the initial discovery of the virus +to the actual sequencing of the genome + + align:start position:0% +to the actual sequencing of the genome + + + align:start position:0% +to the actual sequencing of the genome +which had happened by later on in the + + align:start position:0% +which had happened by later on in the + + + align:start position:0% +which had happened by later on in the +course uh smallpox was a disease we + + align:start position:0% +course uh smallpox was a disease we + + + align:start position:0% +course uh smallpox was a disease we +thought that we' eliminated but now it's + + align:start position:0% +thought that we' eliminated but now it's + + + align:start position:0% +thought that we' eliminated but now it's +come back as a biot terrorism threat and + + align:start position:0% +come back as a biot terrorism threat and + + + align:start position:0% +come back as a biot terrorism threat and +there's increased + + align:start position:0% +there's increased + + + align:start position:0% +there's increased +uh study of of small po pox it's + + align:start position:0% +uh study of of small po pox it's + + + align:start position:0% +uh study of of small po pox it's +something we have to worry about again + + align:start position:0% +something we have to worry about again + + + align:start position:0% +something we have to worry about again +here's another example um this is + + align:start position:0% +here's another example um this is + + + align:start position:0% +here's another example um this is +picture showing the start of a trans + + align:start position:0% +picture showing the start of a trans + + + align:start position:0% +picture showing the start of a trans +genic animal we'll talk about how this + + align:start position:0% +genic animal we'll talk about how this + + + align:start position:0% +genic animal we'll talk about how this +uh process goes later in the course and + + align:start position:0% +uh process goes later in the course and + + + align:start position:0% +uh process goes later in the course and +it's it's related also to this whole + + align:start position:0% +it's it's related also to this whole + + + align:start position:0% +it's it's related also to this whole +issue of cloning uh uh using the sense + + align:start position:0% +issue of cloning uh uh using the sense + + + align:start position:0% +issue of cloning uh uh using the sense +of the word such as in trying to clone a + + align:start position:0% +of the word such as in trying to clone a + + + align:start position:0% +of the word such as in trying to clone a +human or clone an animal to make uh a + + align:start position:0% +human or clone an animal to make uh a + + + align:start position:0% +human or clone an animal to make uh a +genetically identical copy so see there + + align:start position:0% +genetically identical copy so see there + + + align:start position:0% +genetically identical copy so see there +are a couple of different uses so the + + align:start position:0% +are a couple of different uses so the + + + align:start position:0% +are a couple of different uses so the +word cloning as we go through the + + align:start position:0% +word cloning as we go through the + + + align:start position:0% +word cloning as we go through the +course um there's a lot of fuss in the + + align:start position:0% +course um there's a lot of fuss in the + + + align:start position:0% +course um there's a lot of fuss in the +in the news in the newspapers about + + align:start position:0% +in the news in the newspapers about + + + align:start position:0% +in the news in the newspapers about +genetically modified food um and people + + align:start position:0% +genetically modified food um and people + + + align:start position:0% +genetically modified food um and people +have different positions on it here's a + + align:start position:0% +have different positions on it here's a + + + align:start position:0% +have different positions on it here's a +case where I think the benefit of a + + align:start position:0% +case where I think the benefit of a + + + align:start position:0% +case where I think the benefit of a +genetically modified food could hardly + + align:start position:0% +genetically modified food could hardly + + + align:start position:0% +genetically modified food could hardly +be argued with um about two-thirds of + + align:start position:0% +be argued with um about two-thirds of + + + align:start position:0% +be argued with um about two-thirds of +the world's population uses rice as + + align:start position:0% +the world's population uses rice as + + + align:start position:0% +the world's population uses rice as +their primary source of of food one of + + align:start position:0% +their primary source of of food one of + + + align:start position:0% +their primary source of of food one of +the problems with rice is it doesn't + + align:start position:0% +the problems with rice is it doesn't + + + align:start position:0% +the problems with rice is it doesn't +make beta katene beta carotene is what + + align:start position:0% +make beta katene beta carotene is what + + + align:start position:0% +make beta katene beta carotene is what +our bodies take and use to make vitamin + + align:start position:0% +our bodies take and use to make vitamin + + + align:start position:0% +our bodies take and use to make vitamin +A if you have a vitamin A deficiency uh + + align:start position:0% +A if you have a vitamin A deficiency uh + + + align:start position:0% +A if you have a vitamin A deficiency uh +people are prone to infection they have + + align:start position:0% +people are prone to infection they have + + + align:start position:0% +people are prone to infection they have +immune deficiencies in their immune + + align:start position:0% +immune deficiencies in their immune + + + align:start position:0% +immune deficiencies in their immune +system and and blindness and this this + + align:start position:0% +system and and blindness and this this + + + align:start position:0% +system and and blindness and this this +deficiency of vitamin A caused by eating + + align:start position:0% +deficiency of vitamin A caused by eating + + + align:start position:0% +deficiency of vitamin A caused by eating +rice afflicts about 400 million people + + align:start position:0% +rice afflicts about 400 million people + + + align:start position:0% +rice afflicts about 400 million people +worldwide but rice is only + + align:start position:0% +worldwide but rice is only + + + align:start position:0% +worldwide but rice is only +two chemical steps away from being able + + align:start position:0% +two chemical steps away from being able + + + align:start position:0% +two chemical steps away from being able +to make beta katene this is a + + align:start position:0% +to make beta katene this is a + + + align:start position:0% +to make beta katene this is a +genetically modified version of of rice + + align:start position:0% +genetically modified version of of rice + + + align:start position:0% +genetically modified version of of rice +that has those two extra steps inserted + + align:start position:0% +that has those two extra steps inserted + + + align:start position:0% +that has those two extra steps inserted +in it you can see it's golden because + + align:start position:0% +in it you can see it's golden because + + + align:start position:0% +in it you can see it's golden because +it's making beta carotene if people were + + align:start position:0% +it's making beta carotene if people were + + + align:start position:0% +it's making beta carotene if people were +to eat that form of rice then they + + align:start position:0% +to eat that form of rice then they + + + align:start position:0% +to eat that form of rice then they +wouldn't have this problem with vitamin + + align:start position:0% +wouldn't have this problem with vitamin + + + align:start position:0% +wouldn't have this problem with vitamin +A + + align:start position:0% +A + + + align:start position:0% +A +deficiency Penny uh Chisum in her part + + align:start position:0% +deficiency Penny uh Chisum in her part + + + align:start position:0% +deficiency Penny uh Chisum in her part +of the course will be considering things + + align:start position:0% +of the course will be considering things + + + align:start position:0% +of the course will be considering things +at a more Global level uh here's a + + align:start position:0% +at a more Global level uh here's a + + + align:start position:0% +at a more Global level uh here's a +picture of our planet and there issues + + align:start position:0% +picture of our planet and there issues + + + align:start position:0% +picture of our planet and there issues +that you know about there this is a the + + align:start position:0% +that you know about there this is a the + + + align:start position:0% +that you know about there this is a the +carbon dioxide level in the atmosphere + + align:start position:0% +carbon dioxide level in the atmosphere + + + align:start position:0% +carbon dioxide level in the atmosphere +are are rising and uh that's a real + + align:start position:0% +are are rising and uh that's a real + + + align:start position:0% +are are rising and uh that's a real +phenomena that shows from 1960 to + + align:start position:0% +phenomena that shows from 1960 to + + + align:start position:0% +phenomena that shows from 1960 to +1995 uh + + align:start position:0% +1995 uh + + + align:start position:0% +1995 uh +the this is associated with a uh global + + align:start position:0% +the this is associated with a uh global + + + align:start position:0% +the this is associated with a uh global +warming that again is undeniable that + + align:start position:0% +warming that again is undeniable that + + + align:start position:0% +warming that again is undeniable that +it's happening you'll see stuff in the + + align:start position:0% +it's happening you'll see stuff in the + + + align:start position:0% +it's happening you'll see stuff in the +papers uh and these gases particularly + + align:start position:0% +papers uh and these gases particularly + + + align:start position:0% +papers uh and these gases particularly +carbon dioxide and methane that are + + align:start position:0% +carbon dioxide and methane that are + + + align:start position:0% +carbon dioxide and methane that are +known as greenhouse gases are playing a + + align:start position:0% +known as greenhouse gases are playing a + + + align:start position:0% +known as greenhouse gases are playing a +role in that and probably mankind is + + align:start position:0% +role in that and probably mankind is + + + align:start position:0% +role in that and probably mankind is +playing a role in the production of + + align:start position:0% +playing a role in the production of + + + align:start position:0% +playing a role in the production of +those gases and hence in global warming + + align:start position:0% +those gases and hence in global warming + + + align:start position:0% +those gases and hence in global warming +and and Penny will talk to you a little + + align:start position:0% +and and Penny will talk to you a little + + + align:start position:0% +and and Penny will talk to you a little +more about that uh right here at MIT um + + align:start position:0% +more about that uh right here at MIT um + + + align:start position:0% +more about that uh right here at MIT um +Mario Molina in Eeps uh discovered the + + align:start position:0% +Mario Molina in Eeps uh discovered the + + + align:start position:0% +Mario Molina in Eeps uh discovered the +ozone hole got a Nobel Prize for that + + align:start position:0% +ozone hole got a Nobel Prize for that + + + align:start position:0% +ozone hole got a Nobel Prize for that +ozone is important because it absorbs UV + + align:start position:0% +ozone is important because it absorbs UV + + + align:start position:0% +ozone is important because it absorbs UV +uh critical stuff um component of + + align:start position:0% +uh critical stuff um component of + + + align:start position:0% +uh critical stuff um component of +ultraviolet radiation that would damage + + align:start position:0% +ultraviolet radiation that would damage + + + align:start position:0% +ultraviolet radiation that would damage +ourselves if we were exposed to it and + + align:start position:0% +ourselves if we were exposed to it and + + + align:start position:0% +ourselves if we were exposed to it and +because of + + align:start position:0% +because of + + + align:start position:0% +because of +emission of fluorocarbons in the in the + + align:start position:0% +emission of fluorocarbons in the in the + + + align:start position:0% +emission of fluorocarbons in the in the +environment this large hole de developed + + align:start position:0% +environment this large hole de developed + + + align:start position:0% +environment this large hole de developed +over Antarctica if that had spread it + + align:start position:0% +over Antarctica if that had spread it + + + align:start position:0% +over Antarctica if that had spread it +would have been a a real disaster and + + align:start position:0% +would have been a a real disaster and + + + align:start position:0% +would have been a a real disaster and +that seems to be the efforts to cut down + + align:start position:0% +that seems to be the efforts to cut down + + + align:start position:0% +that seems to be the efforts to cut down +and the release of Flur carbon seem to + + align:start position:0% +and the release of Flur carbon seem to + + + align:start position:0% +and the release of Flur carbon seem to +be helping with that but again Penny + + align:start position:0% +be helping with that but again Penny + + + align:start position:0% +be helping with that but again Penny +will have more to say those of you + + align:start position:0% +will have more to say those of you + + + align:start position:0% +will have more to say those of you +who lived around here for a little bit + + align:start position:0% +who lived around here for a little bit + + + align:start position:0% +who lived around here for a little bit +probably know that the fishing industry + + align:start position:0% +probably know that the fishing industry + + + align:start position:0% +probably know that the fishing industry +just locally has had a very hard time as + + align:start position:0% +just locally has had a very hard time as + + + align:start position:0% +just locally has had a very hard time as +a fishing boat just up at glass just up + + align:start position:0% +a fishing boat just up at glass just up + + + align:start position:0% +a fishing boat just up at glass just up +the the coast less than an hour from + + align:start position:0% +the the coast less than an hour from + + + align:start position:0% +the the coast less than an hour from +here and part of the problems again are + + align:start position:0% +here and part of the problems again are + + + align:start position:0% +here and part of the problems again are +caused by mismanagement of the resources + + align:start position:0% +caused by mismanagement of the resources + + + align:start position:0% +caused by mismanagement of the resources +where the the fish have been stocks have + + align:start position:0% +where the the fish have been stocks have + + + align:start position:0% +where the the fish have been stocks have +been over fish so the some of the + + align:start position:0% +been over fish so the some of the + + + align:start position:0% +been over fish so the some of the +Fisheries have come to the point of + + align:start position:0% +Fisheries have come to the point of + + + align:start position:0% +Fisheries have come to the point of +collapse or near the in places such as + + align:start position:0% +collapse or near the in places such as + + + align:start position:0% +collapse or near the in places such as +the grand Banks off of Newland land + + align:start position:0% +the grand Banks off of Newland land + + + align:start position:0% +the grand Banks off of Newland land +there has been a collapse and it's not + + align:start position:0% +there has been a collapse and it's not + + + align:start position:0% +there has been a collapse and it's not +at all clear that it can be reversed and + + align:start position:0% +at all clear that it can be reversed and + + + align:start position:0% +at all clear that it can be reversed and +whether they'll be caught in large + + align:start position:0% +whether they'll be caught in large + + + align:start position:0% +whether they'll be caught in large +quantities ever again + + align:start position:0% +quantities ever again + + + align:start position:0% +quantities ever again +there okay so + + align:start position:0% +there okay so + + + align:start position:0% +there okay so +um a variety of ways that we can can + + align:start position:0% +um a variety of ways that we can can + + + align:start position:0% +um a variety of ways that we can can +study biology and I think I'm going to + + align:start position:0% +study biology and I think I'm going to + + + align:start position:0% +study biology and I think I'm going to +begin by outlining um how we do that + + align:start position:0% +begin by outlining um how we do that + + + align:start position:0% +begin by outlining um how we do that +biology uh is an experimental science + + align:start position:0% +biology uh is an experimental science + + + align:start position:0% +biology uh is an experimental science +it's one of the really + + align:start position:0% +it's one of the really + + + align:start position:0% +it's one of the really +important themes that will + + align:start position:0% +important themes that will + + + align:start position:0% +important themes that will +run through + + align:start position:0% +run through + + + align:start position:0% +run through +uh + + align:start position:0% +uh + + + align:start position:0% +uh +this this + + align:start position:0% + + + + align:start position:0% + +course you can't study biology by just + + align:start position:0% +course you can't study biology by just + + + align:start position:0% +course you can't study biology by just +sitting down with a pen and paper room + + align:start position:0% +sitting down with a pen and paper room + + + align:start position:0% +sitting down with a pen and paper room +and thinking you have to get out and + + align:start position:0% +and thinking you have to get out and + + + align:start position:0% +and thinking you have to get out and +find out what's there you need to make + + align:start position:0% +find out what's there you need to make + + + align:start position:0% +find out what's there you need to make +observations you need to try experiments + + align:start position:0% +observations you need to try experiments + + + align:start position:0% +observations you need to try experiments +you need to formulate hypotheses and + + align:start position:0% +you need to formulate hypotheses and + + + align:start position:0% +you need to formulate hypotheses and +test them and either modify your + + align:start position:0% +test them and either modify your + + + align:start position:0% +test them and either modify your +hypothesis or rejected and so on but + + align:start position:0% +hypothesis or rejected and so on but + + + align:start position:0% +hypothesis or rejected and so on but +it's a continue cycle of experimentation + + align:start position:0% +it's a continue cycle of experimentation + + + align:start position:0% +it's a continue cycle of experimentation +and and um making hypotheses and testing + + align:start position:0% +and and um making hypotheses and testing + + + align:start position:0% +and and um making hypotheses and testing +that's the scci scientific method uh at + + align:start position:0% +that's the scci scientific method uh at + + + align:start position:0% +that's the scci scientific method uh at +work and but you can carry that out at + + align:start position:0% +work and but you can carry that out at + + + align:start position:0% +work and but you can carry that out at +different l levels the very highest + + align:start position:0% +different l levels the very highest + + + align:start position:0% +different l levels the very highest +level would be the + + align:start position:0% +level would be the + + + align:start position:0% +level would be the +biosphere there's one + + align:start position:0% + + + + align:start position:0% + +example that's that's Earth it's here + + align:start position:0% +example that's that's Earth it's here + + + align:start position:0% +example that's that's Earth it's here +there are + + align:start position:0% +there are + + + align:start position:0% +there are +um many many uh species of Life uh that + + align:start position:0% +um many many uh species of Life uh that + + + align:start position:0% +um many many uh species of Life uh that +are on there there're many more than + + align:start position:0% +are on there there're many more than + + + align:start position:0% +are on there there're many more than +um than a million + + align:start position:0% + + + + align:start position:0% + +the estimates of how many there are + + align:start position:0% +the estimates of how many there are + + + align:start position:0% +the estimates of how many there are +range from 10 to in total 10 to the 20 + + align:start position:0% +range from 10 to in total 10 to the 20 + + + align:start position:0% +range from 10 to in total 10 to the 20 +million estimated and one of the the big + + align:start position:0% +million estimated and one of the the big + + + align:start position:0% +million estimated and one of the the big +worries right at the moment is that as + + align:start position:0% +worries right at the moment is that as + + + align:start position:0% +worries right at the moment is that as +rainforests are being depleted Source + + align:start position:0% +rainforests are being depleted Source + + + align:start position:0% +rainforests are being depleted Source +parts of the world that are rich s rich + + align:start position:0% +parts of the world that are rich s rich + + + align:start position:0% +parts of the world that are rich s rich +source of biological diversity uh as + + align:start position:0% +source of biological diversity uh as + + + align:start position:0% +source of biological diversity uh as +those are disappearing we're losing + + align:start position:0% +those are disappearing we're losing + + + align:start position:0% +those are disappearing we're losing +diversity at quite a rate um just couple + + align:start position:0% +diversity at quite a rate um just couple + + + align:start position:0% +diversity at quite a rate um just couple +of years ago I had a chance to fly over + + align:start position:0% +of years ago I had a chance to fly over + + + align:start position:0% +of years ago I had a chance to fly over +a part of Brazil and it was just scary + + align:start position:0% +a part of Brazil and it was just scary + + + align:start position:0% +a part of Brazil and it was just scary +to see from the plane how the rainforest + + align:start position:0% +to see from the plane how the rainforest + + + align:start position:0% +to see from the plane how the rainforest +had just being um cut down and you could + + align:start position:0% +had just being um cut down and you could + + + align:start position:0% +had just being um cut down and you could +just see how fast some of that uh the + + align:start position:0% +just see how fast some of that uh the + + + align:start position:0% +just see how fast some of that uh the +rainforest was disappearing and with it + + align:start position:0% +rainforest was disappearing and with it + + + align:start position:0% +rainforest was disappearing and with it +many different types of uh of species + + align:start position:0% +many different types of uh of species + + + align:start position:0% +many different types of uh of species +that only only can live there um one can + + align:start position:0% +that only only can live there um one can + + + align:start position:0% +that only only can live there um one can +look instead uh going down a level at an + + align:start position:0% + + + + align:start position:0% + +ecosystem which is the is a particular + + align:start position:0% + + + + align:start position:0% + +environment and the species of Life + + align:start position:0% +environment and the species of Life + + + align:start position:0% +environment and the species of Life +found in + + align:start position:0% + + + + align:start position:0% + +it and just to give you a couple of + + align:start position:0% +it and just to give you a couple of + + + align:start position:0% +it and just to give you a couple of +examples of that it could be a uh salt + + align:start position:0% +examples of that it could be a uh salt + + + align:start position:0% +examples of that it could be a uh salt +marsh shown here or here's an + + align:start position:0% +marsh shown here or here's an + + + align:start position:0% +marsh shown here or here's an +interesting environment that Penny + + align:start position:0% +interesting environment that Penny + + + align:start position:0% +interesting environment that Penny +Chisum will tell you more about um this + + align:start position:0% +Chisum will tell you more about um this + + + align:start position:0% +Chisum will tell you more about um this +is a black smoker there's a vent several + + align:start position:0% +is a black smoker there's a vent several + + + align:start position:0% +is a black smoker there's a vent several +miles deep in the Pacific Ocean uh the + + align:start position:0% +miles deep in the Pacific Ocean uh the + + + align:start position:0% +miles deep in the Pacific Ocean uh the +Water temperature that's gushing out of + + align:start position:0% +Water temperature that's gushing out of + + + align:start position:0% +Water temperature that's gushing out of +here is around 360° centigrade and + + align:start position:0% +here is around 360° centigrade and + + + align:start position:0% +here is around 360° centigrade and +there's a particular community of life + + align:start position:0% +there's a particular community of life + + + align:start position:0% +there's a particular community of life +that's able to grow around these around + + align:start position:0% +that's able to grow around these around + + + align:start position:0% +that's able to grow around these around +these uh deep Vents and Penny will tell + + align:start position:0% +these uh deep Vents and Penny will tell + + + align:start position:0% +these uh deep Vents and Penny will tell +you more um more about that then going + + align:start position:0% +you more um more about that then going + + + align:start position:0% +you more um more about that then going +down yet another level you can come to a + + align:start position:0% + + + + align:start position:0% + +population this is interacting + + align:start position:0% + + + + align:start position:0% + +or in breeding uh organisms an example + + align:start position:0% +or in breeding uh organisms an example + + + align:start position:0% +or in breeding uh organisms an example +might be the fiddler crabs in a in a + + align:start position:0% +might be the fiddler crabs in a in a + + + align:start position:0% +might be the fiddler crabs in a in a +salt marsh or or here we see an + + align:start position:0% +salt marsh or or here we see an + + + align:start position:0% +salt marsh or or here we see an +interesting population these are tube + + align:start position:0% +interesting population these are tube + + + align:start position:0% +interesting population these are tube +worms that are up to a meter or more in + + align:start position:0% +worms that are up to a meter or more in + + + align:start position:0% +worms that are up to a meter or more in +length you find down at these um these + + align:start position:0% +length you find down at these um these + + + align:start position:0% +length you find down at these um these +black smokers if we move down yet + + align:start position:0% +black smokers if we move down yet + + + align:start position:0% +black smokers if we move down yet +another level + + align:start position:0% + + + + align:start position:0% + +we come to organisms um organisms have + + align:start position:0% +we come to organisms um organisms have + + + align:start position:0% +we come to organisms um organisms have +uh three important sort of + + align:start position:0% +uh three important sort of + + + align:start position:0% +uh three important sort of +characteristics that we'll talk quite a + + align:start position:0% +characteristics that we'll talk quite a + + + align:start position:0% +characteristics that we'll talk quite a +bit about in this course they carry + + align:start position:0% + + + + align:start position:0% + +out metabolism which is a sum of all the + + align:start position:0% +out metabolism which is a sum of all the + + + align:start position:0% +out metabolism which is a sum of all the +different chemical reactions necessary + + align:start position:0% +different chemical reactions necessary + + + align:start position:0% +different chemical reactions necessary +uh for life they undergo + + align:start position:0% + + + + align:start position:0% + +regulated + + align:start position:0% + + + + align:start position:0% + +growth and they + + align:start position:0% +growth and they + + + align:start position:0% +growth and they +reproduce and the sort of fundamental + + align:start position:0% +reproduce and the sort of fundamental + + + align:start position:0% +reproduce and the sort of fundamental +unit of of life that we will talk about + + align:start position:0% +unit of of life that we will talk about + + + align:start position:0% +unit of of life that we will talk about +over and over again in this course is + + align:start position:0% +over and over again in this course is + + + align:start position:0% +over and over again in this course is +known as a + + align:start position:0% +known as a + + + align:start position:0% +known as a +cell and life comes in two kinds of + + align:start position:0% +cell and life comes in two kinds of + + + align:start position:0% +cell and life comes in two kinds of +species there's unicellular + + align:start position:0% + + + + align:start position:0% + +life where + + align:start position:0% +life where + + + align:start position:0% +life where +uh uh the organism is just a single cell + + align:start position:0% +uh uh the organism is just a single cell + + + align:start position:0% +uh uh the organism is just a single cell +and a multicell + + align:start position:0% + + + + align:start position:0% + +multicellular forms of of Life uh that + + align:start position:0% +multicellular forms of of Life uh that + + + align:start position:0% +multicellular forms of of Life uh that +are made of many different types of + + align:start position:0% +are made of many different types of + + + align:start position:0% +are made of many different types of +cells what's a + + align:start position:0% +cells what's a + + + align:start position:0% +cells what's a +cell one of the secrets to life uh it's + + align:start position:0% +cell one of the secrets to life uh it's + + + align:start position:0% +cell one of the secrets to life uh it's +a little tiny bit of the universe that's + + align:start position:0% +a little tiny bit of the universe that's + + + align:start position:0% +a little tiny bit of the universe that's +surrounded by a boundary + + align:start position:0% + + + + align:start position:0% + +it's given the special name of a me a + + align:start position:0% +it's given the special name of a me a + + + align:start position:0% +it's given the special name of a me a +membrane uh it's selective uh not very + + align:start position:0% +membrane uh it's selective uh not very + + + align:start position:0% +membrane uh it's selective uh not very +permeable to most things and cells are + + align:start position:0% +permeable to most things and cells are + + + align:start position:0% +permeable to most things and cells are +able to put little importers and + + align:start position:0% +able to put little importers and + + + align:start position:0% +able to put little importers and +exporters and things that control the + + align:start position:0% +exporters and things that control the + + + align:start position:0% +exporters and things that control the +passage of things across the membrane + + align:start position:0% +passage of things across the membrane + + + align:start position:0% +passage of things across the membrane +and by isolating the inside of a cell + + align:start position:0% +and by isolating the inside of a cell + + + align:start position:0% +and by isolating the inside of a cell +from all the rest of the Universe um + + align:start position:0% +from all the rest of the Universe um + + + align:start position:0% +from all the rest of the Universe um +that's one of the the principles that + + align:start position:0% +that's one of the the principles that + + + align:start position:0% +that's one of the the principles that +makes uh that makes life + + align:start position:0% +makes uh that makes life + + + align:start position:0% +makes uh that makes life +uh possible um we have a couple of + + align:start position:0% +uh possible um we have a couple of + + + align:start position:0% +uh possible um we have a couple of +examples of uh of organisms here here's + + align:start position:0% +examples of uh of organisms here here's + + + align:start position:0% +examples of uh of organisms here here's +some clams that grow down at those black + + align:start position:0% +some clams that grow down at those black + + + align:start position:0% +some clams that grow down at those black +smokers and they can get pretty large + + align:start position:0% +smokers and they can get pretty large + + + align:start position:0% +smokers and they can get pretty large +and I say penny will talk a bit more + + align:start position:0% +and I say penny will talk a bit more + + + align:start position:0% +and I say penny will talk a bit more +about this we have this really amazing + + align:start position:0% +about this we have this really amazing + + + align:start position:0% +about this we have this really amazing +diversity of of life forms that uh we + + align:start position:0% +diversity of of life forms that uh we + + + align:start position:0% +diversity of of life forms that uh we +find on this on this planet however we + + align:start position:0% +find on this on this planet however we + + + align:start position:0% +find on this on this planet however we +can if we think about this division into + + align:start position:0% +can if we think about this division into + + + align:start position:0% +can if we think about this division into +uni + + align:start position:0% + + + + align:start position:0% + +cellular + + align:start position:0% +cellular + + + align:start position:0% +cellular +multicellular organisms unicellular + + align:start position:0% +multicellular organisms unicellular + + + align:start position:0% +multicellular organisms unicellular +organisms include things that + + align:start position:0% +organisms include things that + + + align:start position:0% +organisms include things that +you're familiar with they're bacteria + + align:start position:0% +you're familiar with they're bacteria + + + align:start position:0% +you're familiar with they're bacteria +there's a picture of just eoli cells and + + align:start position:0% +there's a picture of just eoli cells and + + + align:start position:0% +there's a picture of just eoli cells and +we'll be talking EOL about eoli quite a + + align:start position:0% +we'll be talking EOL about eoli quite a + + + align:start position:0% +we'll be talking EOL about eoli quite a +bit as a model organism as we go through + + align:start position:0% +bit as a model organism as we go through + + + align:start position:0% +bit as a model organism as we go through +the through the course it's been uh by + + align:start position:0% +the through the course it's been uh by + + + align:start position:0% +the through the course it's been uh by +studying eoli + + align:start position:0% +studying eoli + + + align:start position:0% +studying eoli +have learned many important things that + + align:start position:0% +have learned many important things that + + + align:start position:0% +have learned many important things that +apply to to all of life uh another kind + + align:start position:0% +apply to to all of life uh another kind + + + align:start position:0% +apply to to all of life uh another kind +of + + align:start position:0% +of + + + align:start position:0% +of +important uh single cell organism + + align:start position:0% +important uh single cell organism + + + align:start position:0% +important uh single cell organism +unicellular organism is yeast that's + + align:start position:0% +unicellular organism is yeast that's + + + align:start position:0% +unicellular organism is yeast that's +those are pictures of uh yeast uh sacris + + align:start position:0% +those are pictures of uh yeast uh sacris + + + align:start position:0% +those are pictures of uh yeast uh sacris +that are used in baking bread or in uh + + align:start position:0% +that are used in baking bread or in uh + + + align:start position:0% +that are used in baking bread or in uh +brewing beer or or making wine another + + align:start position:0% +brewing beer or or making wine another + + + align:start position:0% +brewing beer or or making wine another +one you're all familiar + + align:start position:0% +one you're all familiar + + + align:start position:0% +one you're all familiar +with are algae which are single celled + + align:start position:0% +with are algae which are single celled + + + align:start position:0% +with are algae which are single celled +uh organisms that are able to carry out + + align:start position:0% +uh organisms that are able to carry out + + + align:start position:0% +uh organisms that are able to carry out +photosynthesis and we'll be talking + + align:start position:0% +photosynthesis and we'll be talking + + + align:start position:0% +photosynthesis and we'll be talking +about + + align:start position:0% +about + + + align:start position:0% +about +that if uh we think of uh an example of + + align:start position:0% +that if uh we think of uh an example of + + + align:start position:0% +that if uh we think of uh an example of +a of a multicellular organism then there + + align:start position:0% +a of a multicellular organism then there + + + align:start position:0% +a of a multicellular organism then there +we see there are different levels at + + align:start position:0% +we see there are different levels at + + + align:start position:0% +we see there are different levels at +which we can think about this we could + + align:start position:0% +which we can think about this we could + + + align:start position:0% +which we can think about this we could +take uh for example + + align:start position:0% +take uh for example + + + align:start position:0% +take uh for example +uh a picture of me uh just an + + align:start position:0% +uh a picture of me uh just an + + + align:start position:0% +uh a picture of me uh just an +anatomically correct uh diagram + + align:start position:0% +anatomically correct uh diagram + + + align:start position:0% +anatomically correct uh diagram +here that + + align:start position:0% +here that + + + align:start position:0% +here that +I'm made up as you are of about 10 to + + align:start position:0% +I'm made up as you are of about 10 to + + + align:start position:0% +I'm made up as you are of about 10 to +the + + align:start position:0% + + + + align:start position:0% + +14th human human + + align:start position:0% +14th human human + + + align:start position:0% +14th human human +cells we all started out as a single uh + + align:start position:0% +cells we all started out as a single uh + + + align:start position:0% +cells we all started out as a single uh +fertilized egg as a fertilized egg which + + align:start position:0% +fertilized egg as a fertilized egg which + + + align:start position:0% +fertilized egg as a fertilized egg which +is a single cell and by the time uh + + align:start position:0% +is a single cell and by the time uh + + + align:start position:0% +is a single cell and by the time uh +we're grown up we have about 10 to the + + align:start position:0% +we're grown up we have about 10 to the + + + align:start position:0% +we're grown up we have about 10 to the +14th human cells just a tremendous + + align:start position:0% +14th human cells just a tremendous + + + align:start position:0% +14th human cells just a tremendous +amount of cell growth that had to happen + + align:start position:0% +amount of cell growth that had to happen + + + align:start position:0% +amount of cell growth that had to happen +and uh specialization the other thing + + align:start position:0% +and uh specialization the other thing + + + align:start position:0% +and uh specialization the other thing +you may not appreciate is that we have + + align:start position:0% +you may not appreciate is that we have + + + align:start position:0% +you may not appreciate is that we have +an ecosystem inside us in our our + + align:start position:0% +an ecosystem inside us in our our + + + align:start position:0% +an ecosystem inside us in our our +gastrointestinal tract the uh this part + + align:start position:0% +gastrointestinal tract the uh this part + + + align:start position:0% +gastrointestinal tract the uh this part +the intestine having the highest + + align:start position:0% +the intestine having the highest + + + align:start position:0% +the intestine having the highest +concentration of microorganisms but + + align:start position:0% +concentration of microorganisms but + + + align:start position:0% +concentration of microorganisms but +they're about 10 to the 14th + + align:start position:0% +they're about 10 to the 14th + + + align:start position:0% +they're about 10 to the 14th +bacteria also inside of our inside of + + align:start position:0% +bacteria also inside of our inside of + + + align:start position:0% +bacteria also inside of our inside of +our gut so we're actually almost the + + align:start position:0% +our gut so we're actually almost the + + + align:start position:0% +our gut so we're actually almost the +same number of human cells and uh + + align:start position:0% +same number of human cells and uh + + + align:start position:0% +same number of human cells and uh +bacterial cells and if we don't have + + align:start position:0% +bacterial cells and if we don't have + + + align:start position:0% +bacterial cells and if we don't have +those bacteria then our Digest systems + + align:start position:0% +those bacteria then our Digest systems + + + align:start position:0% +those bacteria then our Digest systems +don't uh don't work uh well so if we go + + align:start position:0% +don't uh don't work uh well so if we go + + + align:start position:0% +don't uh don't work uh well so if we go +down from a whole organism a whole + + align:start position:0% +down from a whole organism a whole + + + align:start position:0% +down from a whole organism a whole +multicellular organism then a level then + + align:start position:0% +multicellular organism then a level then + + + align:start position:0% +multicellular organism then a level then +we come to uh an + + align:start position:0% +we come to uh an + + + align:start position:0% +we come to uh an +organ and an example of that might be an + + align:start position:0% +organ and an example of that might be an + + + align:start position:0% +organ and an example of that might be an +i and I think we have a a diagram of an + + align:start position:0% +i and I think we have a a diagram of an + + + align:start position:0% +i and I think we have a a diagram of an +i which is made up of of different uh + + align:start position:0% +i which is made up of of different uh + + + align:start position:0% +i which is made up of of different uh +different parts and if we go down + + align:start position:0% +different parts and if we go down + + + align:start position:0% +different parts and if we go down +another level we come to a + + align:start position:0% +another level we come to a + + + align:start position:0% +another level we come to a +tissue which is now you can begin to see + + align:start position:0% +tissue which is now you can begin to see + + + align:start position:0% +tissue which is now you can begin to see +that the tissue is are made up of groups + + align:start position:0% +that the tissue is are made up of groups + + + align:start position:0% +that the tissue is are made up of groups +of specialized cells an example might + + align:start position:0% +of specialized cells an example might + + + align:start position:0% +of specialized cells an example might +be the retina of of an ie and if we + + align:start position:0% +be the retina of of an ie and if we + + + align:start position:0% +be the retina of of an ie and if we +continue to to go downwards we'll get to + + align:start position:0% +continue to to go downwards we'll get to + + + align:start position:0% +continue to to go downwards we'll get to +single + + align:start position:0% + + + + align:start position:0% + +cells and at this point we're at the + + align:start position:0% +cells and at this point we're at the + + + align:start position:0% +cells and at this point we're at the +same level of detail as when we when we + + align:start position:0% +same level of detail as when we when we + + + align:start position:0% +same level of detail as when we when we +go to when we're talking about a + + align:start position:0% +go to when we're talking about a + + + align:start position:0% +go to when we're talking about a +unicellular um unicellular uh organism + + align:start position:0% +unicellular um unicellular uh organism + + + align:start position:0% +unicellular um unicellular uh organism +we + + align:start position:0% +we + + + align:start position:0% +we +continue down + + align:start position:0% + + + + align:start position:0% + +then we can get to um organel uh these + + align:start position:0% +then we can get to um organel uh these + + + align:start position:0% +then we can get to um organel uh these +are + + align:start position:0% +are + + + align:start position:0% +are +um involved in + + align:start position:0% +um involved in + + + align:start position:0% +um involved in +energy uh production uh energy manag + + align:start position:0% + + + + align:start position:0% + +M mitoch A mitochondrian and a + + align:start position:0% +M mitoch A mitochondrian and a + + + align:start position:0% +M mitoch A mitochondrian and a +chloroplast they're the two principal + + align:start position:0% +chloroplast they're the two principal + + + align:start position:0% +chloroplast they're the two principal +examples of organel that we'll we'll + + align:start position:0% +examples of organel that we'll we'll + + + align:start position:0% +examples of organel that we'll we'll +talk about and if we go down yet another + + align:start position:0% +talk about and if we go down yet another + + + align:start position:0% +talk about and if we go down yet another +level of + + align:start position:0% + + + + align:start position:0% + +organization we get to molecules and + + align:start position:0% +organization we get to molecules and + + + align:start position:0% +organization we get to molecules and +part of the reason that biology has + + align:start position:0% +part of the reason that biology has + + + align:start position:0% +part of the reason that biology has +flourished so well over the last few + + align:start position:0% +flourished so well over the last few + + + align:start position:0% +flourished so well over the last few +decades at MIT is there's been a real + + align:start position:0% +decades at MIT is there's been a real + + + align:start position:0% +decades at MIT is there's been a real +emphasis on looking at things at a + + align:start position:0% +emphasis on looking at things at a + + + align:start position:0% +emphasis on looking at things at a +cellular and molecular level so you're + + align:start position:0% +cellular and molecular level so you're + + + align:start position:0% +cellular and molecular level so you're +going to be hearing a lot about cells + + align:start position:0% +going to be hearing a lot about cells + + + align:start position:0% +going to be hearing a lot about cells +and a lot about uh molecules as we go + + align:start position:0% +and a lot about uh molecules as we go + + + align:start position:0% +and a lot about uh molecules as we go +through this uh through this course + + align:start position:0% +through this uh through this course + + + align:start position:0% +through this uh through this course +here's an example of ropson that's a + + align:start position:0% +here's an example of ropson that's a + + + align:start position:0% +here's an example of ropson that's a +protein we'll be talking what proteins + + align:start position:0% +protein we'll be talking what proteins + + + align:start position:0% +protein we'll be talking what proteins +are but it's a very important class of + + align:start position:0% +are but it's a very important class of + + + align:start position:0% +are but it's a very important class of +molecule in nature in this case proteins + + align:start position:0% +molecule in nature in this case proteins + + + align:start position:0% +molecule in nature in this case proteins +involved in in sensing uh light and + + align:start position:0% +involved in in sensing uh light and + + + align:start position:0% +involved in in sensing uh light and +plays an important part in your vision + + align:start position:0% +plays an important part in your vision + + + align:start position:0% +plays an important part in your vision +here's some another protein you can't + + align:start position:0% +here's some another protein you can't + + + align:start position:0% +here's some another protein you can't +really tell uh what it's doing by just + + align:start position:0% +really tell uh what it's doing by just + + + align:start position:0% +really tell uh what it's doing by just +looking at it but in this case this is + + align:start position:0% +looking at it but in this case this is + + + align:start position:0% +looking at it but in this case this is +one of the is a lethal Factor that's + + align:start position:0% +one of the is a lethal Factor that's + + + align:start position:0% +one of the is a lethal Factor that's +made by Anthrax it's one of the proteins + + align:start position:0% +made by Anthrax it's one of the proteins + + + align:start position:0% +made by Anthrax it's one of the proteins +that Anthrax made makes that's capable + + align:start position:0% +that Anthrax made makes that's capable + + + align:start position:0% +that Anthrax made makes that's capable +of killing you if you get infected with + + align:start position:0% +of killing you if you get infected with + + + align:start position:0% +of killing you if you get infected with +it here's another molecule we'll talk + + align:start position:0% +it here's another molecule we'll talk + + + align:start position:0% +it here's another molecule we'll talk +about in great detail this is DNA it's a + + align:start position:0% +about in great detail this is DNA it's a + + + align:start position:0% +about in great detail this is DNA it's a +you probably all know it's a double + + align:start position:0% +you probably all know it's a double + + + align:start position:0% +you probably all know it's a double +helix two strands of DNA that are held + + align:start position:0% +helix two strands of DNA that are held + + + align:start position:0% +helix two strands of DNA that are held +together by forces will be discussed + + align:start position:0% +together by forces will be discussed + + + align:start position:0% +together by forces will be discussed +it's an absolutely beautiful molecule + + align:start position:0% +it's an absolutely beautiful molecule + + + align:start position:0% +it's an absolutely beautiful molecule +it's fascinated me through all of my + + align:start position:0% +it's fascinated me through all of my + + + align:start position:0% +it's fascinated me through all of my +life and we'll be talking quite a bit + + align:start position:0% +life and we'll be talking quite a bit + + + align:start position:0% +life and we'll be talking quite a bit +about that as the course course goes + + align:start position:0% + + + + align:start position:0% + +on okay + + align:start position:0% +on okay + + + align:start position:0% +on okay +so we can if we're thinking about cells + + align:start position:0% +so we can if we're thinking about cells + + + align:start position:0% +so we can if we're thinking about cells +there are two important kinds of cells + + align:start position:0% +there are two important kinds of cells + + + align:start position:0% +there are two important kinds of cells +that one finds on this + + align:start position:0% + + + + align:start position:0% + +planet procaryotic + + align:start position:0% + + + + align:start position:0% + +cells at least procaryotic organisms + + align:start position:0% +cells at least procaryotic organisms + + + align:start position:0% +cells at least procaryotic organisms +and eukariotic organisms and they each + + align:start position:0% +and eukariotic organisms and they each + + + align:start position:0% +and eukariotic organisms and they each +have are made of cells distinguishable + + align:start position:0% +have are made of cells distinguishable + + + align:start position:0% +have are made of cells distinguishable +from each other i' indicated that a a + + align:start position:0% +from each other i' indicated that a a + + + align:start position:0% +from each other i' indicated that a a +cell is a little bit of the universe + + align:start position:0% +cell is a little bit of the universe + + + align:start position:0% +cell is a little bit of the universe +that's surrounded by a boundary or a + + align:start position:0% + + + + align:start position:0% + +membrane but inside + + align:start position:0% + + + + align:start position:0% + +there some in inside of this is the DNA + + align:start position:0% +there some in inside of this is the DNA + + + align:start position:0% +there some in inside of this is the DNA +which function as the genetic material + + align:start position:0% +which function as the genetic material + + + align:start position:0% +which function as the genetic material +it's the + + align:start position:0% +it's the + + + align:start position:0% +it's the +blueprint for everything that uh that + + align:start position:0% +blueprint for everything that uh that + + + align:start position:0% +blueprint for everything that uh that +cell is going to make and be able to to + + align:start position:0% +cell is going to make and be able to to + + + align:start position:0% +cell is going to make and be able to to +do ultimately everything's encoded there + + align:start position:0% +do ultimately everything's encoded there + + + align:start position:0% +do ultimately everything's encoded there +and in a procaryotic Cell the DNA is + + align:start position:0% +and in a procaryotic Cell the DNA is + + + align:start position:0% +and in a procaryotic Cell the DNA is +free within this uh within this membrane + + align:start position:0% +free within this uh within this membrane + + + align:start position:0% +free within this uh within this membrane +eukaryotic cell also has a membrane + + align:start position:0% + + + + align:start position:0% + +um but the DNA inside is in is uh is + + align:start position:0% +um but the DNA inside is in is uh is + + + align:start position:0% +um but the DNA inside is in is uh is +inside another membrane compartment + + align:start position:0% +inside another membrane compartment + + + align:start position:0% +inside another membrane compartment +known as the + + align:start position:0% + + + + align:start position:0% + +nucleus and this is the DNA uh + + align:start position:0% +nucleus and this is the DNA uh + + + align:start position:0% +nucleus and this is the DNA uh +these procaryotic cells tend to be of + + align:start position:0% +these procaryotic cells tend to be of + + + align:start position:0% +these procaryotic cells tend to be of +the order of uh prometer in length and + + align:start position:0% +the order of uh prometer in length and + + + align:start position:0% +the order of uh prometer in length and +eukariotic cells are usually larger can + + align:start position:0% +eukariotic cells are usually larger can + + + align:start position:0% +eukariotic cells are usually larger can +be + + align:start position:0% +be + + + align:start position:0% +be +uh 10 to 100 parameters um there's quite + + align:start position:0% +uh 10 to 100 parameters um there's quite + + + align:start position:0% +uh 10 to 100 parameters um there's quite +a bit of variation but that gives you at + + align:start position:0% +a bit of variation but that gives you at + + + align:start position:0% +a bit of variation but that gives you at +least some sense of the of the range now + + align:start position:0% +least some sense of the of the range now + + + align:start position:0% +least some sense of the of the range now +I've for years um when I did a diagram + + align:start position:0% +I've for years um when I did a diagram + + + align:start position:0% +I've for years um when I did a diagram +like this I wanted to somehow be able to + + align:start position:0% +like this I wanted to somehow be able to + + + align:start position:0% +like this I wanted to somehow be able to +to show you that these cells were uh + + align:start position:0% +to show you that these cells were uh + + + align:start position:0% +to show you that these cells were uh +interes and just looks on the board so + + align:start position:0% +interes and just looks on the board so + + + align:start position:0% +interes and just looks on the board so +here a couple of pictures just to try + + align:start position:0% +here a couple of pictures just to try + + + align:start position:0% +here a couple of pictures just to try +and do that uh this shows a picture of + + align:start position:0% +and do that uh this shows a picture of + + + align:start position:0% +and do that uh this shows a picture of +eoli uh swimming along and it's um the + + align:start position:0% +eoli uh swimming along and it's um the + + + align:start position:0% +eoli uh swimming along and it's um the +way this image is being taken lets you + + align:start position:0% +way this image is being taken lets you + + + align:start position:0% +way this image is being taken lets you +see what are called fella but which are + + align:start position:0% +see what are called fella but which are + + + align:start position:0% +see what are called fella but which are +basically the uh propellers uh that + + align:start position:0% +basically the uh propellers uh that + + + align:start position:0% +basically the uh propellers uh that +ecoli have that let it swim uh through + + align:start position:0% +ecoli have that let it swim uh through + + + align:start position:0% +ecoli have that let it swim uh through +the water these are uh long structures + + align:start position:0% +the water these are uh long structures + + + align:start position:0% +the water these are uh long structures +made of proteins that are several B + + align:start position:0% +made of proteins that are several B + + + align:start position:0% +made of proteins that are several B +times the body length of the of the + + align:start position:0% +times the body length of the of the + + + align:start position:0% +times the body length of the of the +bacterium and there's a molecular motor + + align:start position:0% +bacterium and there's a molecular motor + + + align:start position:0% +bacterium and there's a molecular motor +embedded in the bacterium that whirls + + align:start position:0% +embedded in the bacterium that whirls + + + align:start position:0% +embedded in the bacterium that whirls +around at about somewhere between 10 and + + align:start position:0% +around at about somewhere between 10 and + + + align:start position:0% +around at about somewhere between 10 and +100,000 000 RPM and that's what drives + + align:start position:0% +100,000 000 RPM and that's what drives + + + align:start position:0% +100,000 000 RPM and that's what drives +the bacterial forward uh so that was a + + align:start position:0% +the bacterial forward uh so that was a + + + align:start position:0% +the bacterial forward uh so that was a +procaryotic cell uh here's a parium this + + align:start position:0% +procaryotic cell uh here's a parium this + + + align:start position:0% +procaryotic cell uh here's a parium this +is a single celled eukaryotic organism + + align:start position:0% +is a single celled eukaryotic organism + + + align:start position:0% +is a single celled eukaryotic organism +and as you can see here it's capable of + + align:start position:0% +and as you can see here it's capable of + + + align:start position:0% +and as you can see here it's capable of +movement as well in this case it has + + align:start position:0% +movement as well in this case it has + + + align:start position:0% +movement as well in this case it has +Sil along the uh outside that allow it + + align:start position:0% +Sil along the uh outside that allow it + + + align:start position:0% +Sil along the uh outside that allow it +to to move here's an interesting one I + + align:start position:0% +to to move here's an interesting one I + + + align:start position:0% +to to move here's an interesting one I +don't know if any of you could guess + + align:start position:0% +don't know if any of you could guess + + + align:start position:0% +don't know if any of you could guess +what these were these were cells from + + align:start position:0% +what these were these were cells from + + + align:start position:0% +what these were these were cells from +the skin of a mouse um they're on a a + + align:start position:0% +the skin of a mouse um they're on a a + + + align:start position:0% +the skin of a mouse um they're on a a +surface augur surface and as you can see + + align:start position:0% +surface augur surface and as you can see + + + align:start position:0% +surface augur surface and as you can see +they too can move there are a couple of + + align:start position:0% +they too can move there are a couple of + + + align:start position:0% +they too can move there are a couple of +things are important about this um I I + + align:start position:0% +things are important about this um I I + + + align:start position:0% +things are important about this um I I +got this uh slide from Linda Griffith + + align:start position:0% +got this uh slide from Linda Griffith + + + align:start position:0% +got this uh slide from Linda Griffith +who's in the biological engineering + + align:start position:0% +who's in the biological engineering + + + align:start position:0% +who's in the biological engineering +department the time I got it for I think + + align:start position:0% +department the time I got it for I think + + + align:start position:0% +department the time I got it for I think +it was in chemical engineering was uh + + align:start position:0% +it was in chemical engineering was uh + + + align:start position:0% +it was in chemical engineering was uh +several years ago when I got this and um + + align:start position:0% +several years ago when I got this and um + + + align:start position:0% +several years ago when I got this and um +what's what was important about this uh + + align:start position:0% +what's what was important about this uh + + + align:start position:0% +what's what was important about this uh +apart from it being a a very nice little + + align:start position:0% +apart from it being a a very nice little + + + align:start position:0% +apart from it being a a very nice little +movie showing you a a Mamon cell uh + + align:start position:0% +movie showing you a a Mamon cell uh + + + align:start position:0% +movie showing you a a Mamon cell uh +moving around was that I got it uh I + + align:start position:0% +moving around was that I got it uh I + + + align:start position:0% +moving around was that I got it uh I +heard saind to show this during one of + + align:start position:0% +heard saind to show this during one of + + + align:start position:0% +heard saind to show this during one of +her research seminars so here is an + + align:start position:0% +her research seminars so here is an + + + align:start position:0% +her research seminars so here is an +engineer at uh MIT who was showing this + + align:start position:0% +engineer at uh MIT who was showing this + + + align:start position:0% +engineer at uh MIT who was showing this +picture as part of her her research talk + + align:start position:0% +picture as part of her her research talk + + + align:start position:0% +picture as part of her her research talk +and I think those of you who are going + + align:start position:0% +and I think those of you who are going + + + align:start position:0% +and I think those of you who are going +on engineering you may be surprised at + + align:start position:0% +on engineering you may be surprised at + + + align:start position:0% +on engineering you may be surprised at +the extent to which you need to know + + align:start position:0% +the extent to which you need to know + + + align:start position:0% +the extent to which you need to know +about uh biology as you go through your + + align:start position:0% +about uh biology as you go through your + + + align:start position:0% +about uh biology as you go through your +your professional careers + + align:start position:0% + + + + align:start position:0% + +okay um so one of the uh great + + align:start position:0% +okay um so one of the uh great + + + align:start position:0% +okay um so one of the uh great +discoveries that has happened over the + + align:start position:0% +discoveries that has happened over the + + + align:start position:0% +discoveries that has happened over the +last few years that came out of our + + align:start position:0% +last few years that came out of our + + + align:start position:0% +last few years that came out of our +ability to look at DNA and and uh and + + align:start position:0% +ability to look at DNA and and uh and + + + align:start position:0% +ability to look at DNA and and uh and +RNA was the discovery that + + align:start position:0% +RNA was the discovery that + + + align:start position:0% +RNA was the discovery that +that uh the forms of life that are + + align:start position:0% +that uh the forms of life that are + + + align:start position:0% +that uh the forms of life that are +procaryotic + + align:start position:0% +procaryotic + + + align:start position:0% +procaryotic +actually split into two distinct + + align:start position:0% +actually split into two distinct + + + align:start position:0% +actually split into two distinct +kingdoms that are very very different + + align:start position:0% + + + + align:start position:0% + +the + + align:start position:0% + + + + align:start position:0% + +ARA and the bacteria and just to give + + align:start position:0% +ARA and the bacteria and just to give + + + align:start position:0% +ARA and the bacteria and just to give +you a sense of uh the diversity of Life + + align:start position:0% +you a sense of uh the diversity of Life + + + align:start position:0% +you a sense of uh the diversity of Life +I'll just mention a couple of these + + align:start position:0% +I'll just mention a couple of these + + + align:start position:0% +I'll just mention a couple of these +these ARA uh look like bacteria but + + align:start position:0% +these ARA uh look like bacteria but + + + align:start position:0% +these ARA uh look like bacteria but +there is diverged uh from the bacteria + + align:start position:0% +there is diverged uh from the bacteria + + + align:start position:0% +there is diverged uh from the bacteria +as they are from the UK carots uh so + + align:start position:0% +as they are from the UK carots uh so + + + align:start position:0% +as they are from the UK carots uh so +there were sort of three really major + + align:start position:0% +there were sort of three really major + + + align:start position:0% +there were sort of three really major +kingdoms of life and the ARA many of + + align:start position:0% +kingdoms of life and the ARA many of + + + align:start position:0% +kingdoms of life and the ARA many of +them can live in specialized uh + + align:start position:0% +them can live in specialized uh + + + align:start position:0% +them can live in specialized uh +environments + + align:start position:0% +environments + + + align:start position:0% +environments +for example + + align:start position:0% + + + + align:start position:0% + +sulfolobus can live at about 90 de + + align:start position:0% +sulfolobus can live at about 90 de + + + align:start position:0% +sulfolobus can live at about 90 de +centigrade and a pH of somewhere between + + align:start position:0% +centigrade and a pH of somewhere between + + + align:start position:0% +centigrade and a pH of somewhere between +1 and two and so if you see something + + align:start position:0% +1 and two and so if you see something + + + align:start position:0% +1 and two and so if you see something +like a hot springs there are organisms + + align:start position:0% +like a hot springs there are organisms + + + align:start position:0% +like a hot springs there are organisms +such as this that are able to grow in + + align:start position:0% +such as this that are able to grow in + + + align:start position:0% +such as this that are able to grow in +that environment or there are uh + + align:start position:0% +that environment or there are uh + + + align:start position:0% +that environment or there are uh +halophiles salt loving ARA that can grow + + align:start position:0% +halophiles salt loving ARA that can grow + + + align:start position:0% +halophiles salt loving ARA that can grow +in for example in four + + align:start position:0% +in for example in four + + + align:start position:0% +in for example in four +molar sodium chloride and if you've for + + align:start position:0% +molar sodium chloride and if you've for + + + align:start position:0% +molar sodium chloride and if you've for +example ever flown into San Francisco + + align:start position:0% +example ever flown into San Francisco + + + align:start position:0% +example ever flown into San Francisco +Airport coming up from the south over + + align:start position:0% +Airport coming up from the south over + + + align:start position:0% +Airport coming up from the south over +San Jose you've seen things that look + + align:start position:0% +San Jose you've seen things that look + + + align:start position:0% +San Jose you've seen things that look +sort of like these pictures where um + + align:start position:0% +sort of like these pictures where um + + + align:start position:0% +sort of like these pictures where um +seawat is being evaporated down to + + align:start position:0% +seawat is being evaporated down to + + + align:start position:0% +seawat is being evaporated down to +collect the salt and you'll see they're + + align:start position:0% +collect the salt and you'll see they're + + + align:start position:0% +collect the salt and you'll see they're +colored and the reason they're colored + + align:start position:0% +colored and the reason they're colored + + + align:start position:0% +colored and the reason they're colored +is that these uh Halo bacteria are photo + + align:start position:0% +is that these uh Halo bacteria are photo + + + align:start position:0% +is that these uh Halo bacteria are photo +um bacteria that are able to use light + + align:start position:0% +um bacteria that are able to use light + + + align:start position:0% +um bacteria that are able to use light +as an energy source and they make + + align:start position:0% +as an energy source and they make + + + align:start position:0% +as an energy source and they make +pigments that absorb the light and + + align:start position:0% +pigments that absorb the light and + + + align:start position:0% +pigments that absorb the light and +that's why they're why these uh salt + + align:start position:0% +that's why they're why these uh salt + + + align:start position:0% +that's why they're why these uh salt +um areas get get colored a third example + + align:start position:0% +um areas get get colored a third example + + + align:start position:0% +um areas get get colored a third example +would be + + align:start position:0% + + + + align:start position:0% + +methanogens these are uh organisms that + + align:start position:0% +methanogens these are uh organisms that + + + align:start position:0% +methanogens these are uh organisms that +produce methane if you've walked into a + + align:start position:0% +produce methane if you've walked into a + + + align:start position:0% +produce methane if you've walked into a +lake and stepped on the bottom and seen + + align:start position:0% +lake and stepped on the bottom and seen + + + align:start position:0% +lake and stepped on the bottom and seen +little bubbles come up those are uh + + align:start position:0% +little bubbles come up those are uh + + + align:start position:0% +little bubbles come up those are uh +little bubbles of of methane or uh + + align:start position:0% +little bubbles of of methane or uh + + + align:start position:0% +little bubbles of of methane or uh +another place where you find methanogens + + align:start position:0% +another place where you find methanogens + + + align:start position:0% +another place where you find methanogens +are inside of cows now some of you may + + align:start position:0% +are inside of cows now some of you may + + + align:start position:0% +are inside of cows now some of you may +not know uh that a cow is more or less a + + align:start position:0% +not know uh that a cow is more or less a + + + align:start position:0% +not know uh that a cow is more or less a +uh walking uh anerobic + + align:start position:0% +uh walking uh anerobic + + + align:start position:0% +uh walking uh anerobic +fermenter here if we have + + align:start position:0% +fermenter here if we have + + + align:start position:0% +fermenter here if we have +a an anatomically correct uh picture of + + align:start position:0% +a an anatomically correct uh picture of + + + align:start position:0% +a an anatomically correct uh picture of +a of a cow uh the inside of the cow + + align:start position:0% +a of a cow uh the inside of the cow + + + align:start position:0% +a of a cow uh the inside of the cow +there's a large + + align:start position:0% +there's a large + + + align:start position:0% +there's a large +chamber as the rumin which where there's + + align:start position:0% +chamber as the rumin which where there's + + + align:start position:0% +chamber as the rumin which where there's +no oxygen and there's a culture of micro + + align:start position:0% +no oxygen and there's a culture of micro + + + align:start position:0% +no oxygen and there's a culture of micro +organisms there that includes + + align:start position:0% +organisms there that includes + + + align:start position:0% +organisms there that includes +methanogens and it's this combination of + + align:start position:0% +methanogens and it's this combination of + + + align:start position:0% +methanogens and it's this combination of +microorganisms that en cows to uh eat + + align:start position:0% +microorganisms that en cows to uh eat + + + align:start position:0% +microorganisms that en cows to uh eat +grass that we can't manage to uh get + + align:start position:0% +grass that we can't manage to uh get + + + align:start position:0% +grass that we can't manage to uh get +energy from and as a byproduct uh of + + align:start position:0% +energy from and as a byproduct uh of + + + align:start position:0% +energy from and as a byproduct uh of +this specialized type of metabolism + + align:start position:0% +this specialized type of metabolism + + + align:start position:0% +this specialized type of metabolism +produces methane and a cow burps + + align:start position:0% +produces methane and a cow burps + + + align:start position:0% +produces methane and a cow burps +something of the order of 400 liters a + + align:start position:0% +something of the order of 400 liters a + + + align:start position:0% +something of the order of 400 liters a +day of uh of + + align:start position:0% +day of uh of + + + align:start position:0% +day of uh of +methane okay so one last thing then + + align:start position:0% +methane okay so one last thing then + + + align:start position:0% +methane okay so one last thing then +that's just to kind of pull this all + + align:start position:0% +that's just to kind of pull this all + + + align:start position:0% +that's just to kind of pull this all +together is that these organel that I + + align:start position:0% +together is that these organel that I + + + align:start position:0% +together is that these organel that I +mentioned which + + align:start position:0% +mentioned which + + + align:start position:0% +mentioned which +are also membrane compartments that are + + align:start position:0% +are also membrane compartments that are + + + align:start position:0% +are also membrane compartments that are +found in eukariotic cells and either + + align:start position:0% +found in eukariotic cells and either + + + align:start position:0% +found in eukariotic cells and either +could are the + + align:start position:0% + + + + align:start position:0% + +mitochondria uh or + + align:start position:0% +mitochondria uh or + + + align:start position:0% +mitochondria uh or +chloroplast uh there's pretty strong + + align:start position:0% +chloroplast uh there's pretty strong + + + align:start position:0% +chloroplast uh there's pretty strong +evidence at this point that these aose + + align:start position:0% +evidence at this point that these aose + + + align:start position:0% +evidence at this point that these aose +from bacteria that were things that that + + align:start position:0% +from bacteria that were things that that + + + align:start position:0% +from bacteria that were things that that +we've uh you're more familiar with + + align:start position:0% +we've uh you're more familiar with + + + align:start position:0% +we've uh you're more familiar with +things + + align:start position:0% +things + + + align:start position:0% +things +like eoli + + align:start position:0% +like eoli + + + align:start position:0% +like eoli +or streptococus + + align:start position:0% +or streptococus + + + align:start position:0% +or streptococus +that + + align:start position:0% +that + + + align:start position:0% +that +um causes strep throat or + + align:start position:0% +um causes strep throat or + + + align:start position:0% +um causes strep throat or +um uh the lactic acid bacteria that + + align:start position:0% +um uh the lactic acid bacteria that + + + align:start position:0% +um uh the lactic acid bacteria that +cause the the milk to turn into yogurt + + align:start position:0% +cause the the milk to turn into yogurt + + + align:start position:0% +cause the the milk to turn into yogurt +which some of you probably had for for + + align:start position:0% +which some of you probably had for for + + + align:start position:0% +which some of you probably had for for +lunch today that these organel the + + align:start position:0% +lunch today that these organel the + + + align:start position:0% +lunch today that these organel the +mitochondria and the chloroplast were + + align:start position:0% +mitochondria and the chloroplast were + + + align:start position:0% +mitochondria and the chloroplast were +derived from particular type of bacteria + + align:start position:0% +derived from particular type of bacteria + + + align:start position:0% +derived from particular type of bacteria +that probably first got transiently + + align:start position:0% +that probably first got transiently + + + align:start position:0% +that probably first got transiently +associated with developing eukariotic + + align:start position:0% +associated with developing eukariotic + + + align:start position:0% +associated with developing eukariotic +cells sometime back in evolution and + + align:start position:0% +cells sometime back in evolution and + + + align:start position:0% +cells sometime back in evolution and +eventually became captured and became a + + align:start position:0% +eventually became captured and became a + + + align:start position:0% +eventually became captured and became a +permanent part of the uh of the + + align:start position:0% +permanent part of the uh of the + + + align:start position:0% +permanent part of the uh of the +eukariotic cell the mitochondrian is + + align:start position:0% +eukariotic cell the mitochondrian is + + + align:start position:0% +eukariotic cell the mitochondrian is +thought to derived from something that + + align:start position:0% +thought to derived from something that + + + align:start position:0% +thought to derived from something that +looks like today's present day risia + + align:start position:0% +looks like today's present day risia + + + align:start position:0% +looks like today's present day risia +which we'll talk about that form an + + align:start position:0% +which we'll talk about that form an + + + align:start position:0% +which we'll talk about that form an +intracellular infection of plants a rsia + + align:start position:0% +intracellular infection of plants a rsia + + + align:start position:0% +intracellular infection of plants a rsia +which is a chronic intracellular + + align:start position:0% +which is a chronic intracellular + + + align:start position:0% +which is a chronic intracellular +pathogen the mitochondria looked as + + align:start position:0% +pathogen the mitochondria looked as + + + align:start position:0% +pathogen the mitochondria looked as +though they came from something related + + align:start position:0% +though they came from something related + + + align:start position:0% +though they came from something related +to that the chloroplasts look as though + + align:start position:0% +to that the chloroplasts look as though + + + align:start position:0% +to that the chloroplasts look as though +they came from um a bacterium that was + + align:start position:0% +they came from um a bacterium that was + + + align:start position:0% +they came from um a bacterium that was +able to carry out photosynthesis which + + align:start position:0% +able to carry out photosynthesis which + + + align:start position:0% +able to carry out photosynthesis which +will also be talking about so I want to + + align:start position:0% +will also be talking about so I want to + + + align:start position:0% +will also be talking about so I want to +close by giving you just a quick little + + align:start position:0% +close by giving you just a quick little + + + align:start position:0% +close by giving you just a quick little +snapshot of evolution because I'm hoping + + align:start position:0% +snapshot of evolution because I'm hoping + + + align:start position:0% +snapshot of evolution because I'm hoping +this will maybe make some of the things + + align:start position:0% +this will maybe make some of the things + + + align:start position:0% +this will maybe make some of the things +that we talk about in this course + + align:start position:0% +that we talk about in this course + + + align:start position:0% +that we talk about in this course +clearer so what we're going to + + align:start position:0% +clearer so what we're going to + + + align:start position:0% +clearer so what we're going to +do is we're going + + align:start position:0% + + + + align:start position:0% + +to look back from + + align:start position:0% +to look back from + + + align:start position:0% +to look back from +4.5 billion years ago when the Earth + + align:start position:0% + + + + align:start position:0% + +was the Earth was just + + align:start position:0% + + + + align:start position:0% + +forming so now and I'm just going to try + + align:start position:0% +forming so now and I'm just going to try + + + align:start position:0% +forming so now and I'm just going to try +and give a few uh key things sort of + + align:start position:0% +and give a few uh key things sort of + + + align:start position:0% +and give a few uh key things sort of +landmarks as we as we go along + + align:start position:0% + + + + align:start position:0% + +so about 4.5 billion years ago there was + + align:start position:0% +so about 4.5 billion years ago there was + + + align:start position:0% +so about 4.5 billion years ago there was +methane carbon + + align:start position:0% +methane carbon + + + align:start position:0% +methane carbon +dioxide ammonium hydrogen gas nitrogen + + align:start position:0% +dioxide ammonium hydrogen gas nitrogen + + + align:start position:0% +dioxide ammonium hydrogen gas nitrogen +gas water but + + align:start position:0% +gas water but + + + align:start position:0% +gas water but +importantly no oxygen at that point now + + align:start position:0% +importantly no oxygen at that point now + + + align:start position:0% +importantly no oxygen at that point now +there's a lot of debate as to how uh + + align:start position:0% +there's a lot of debate as to how uh + + + align:start position:0% +there's a lot of debate as to how uh +life initially came one of the prevalent + + align:start position:0% +life initially came one of the prevalent + + + align:start position:0% +life initially came one of the prevalent +theories at this point is there's + + align:start position:0% +theories at this point is there's + + + align:start position:0% +theories at this point is there's +something called an RNA world this is + + align:start position:0% +something called an RNA world this is + + + align:start position:0% +something called an RNA world this is +just a + + align:start position:0% +just a + + + align:start position:0% +just a +hypothesis in which it's thought that + + align:start position:0% +hypothesis in which it's thought that + + + align:start position:0% +hypothesis in which it's thought that +perhaps the molecule RNA which we'll + + align:start position:0% +perhaps the molecule RNA which we'll + + + align:start position:0% +perhaps the molecule RNA which we'll +talk about played role as both uh an + + align:start position:0% +talk about played role as both uh an + + + align:start position:0% +talk about played role as both uh an +something that was able to catalyze + + align:start position:0% +something that was able to catalyze + + + align:start position:0% +something that was able to catalyze +chemical reactions and therefore did + + align:start position:0% +chemical reactions and therefore did + + + align:start position:0% +chemical reactions and therefore did +things actively and also stored uh + + align:start position:0% +things actively and also stored uh + + + align:start position:0% +things actively and also stored uh +information but in any case the best + + align:start position:0% +information but in any case the best + + + align:start position:0% +information but in any case the best +guess is that the + + align:start position:0% +guess is that the + + + align:start position:0% +guess is that the +first life that + + align:start position:0% +first life that + + + align:start position:0% +first life that +uh was about 3.8 billion years ago + + align:start position:0% +uh was about 3.8 billion years ago + + + align:start position:0% +uh was about 3.8 billion years ago +somewhere in that vicinity it was + + align:start position:0% +somewhere in that vicinity it was + + + align:start position:0% +somewhere in that vicinity it was +something that probably resembled most + + align:start position:0% +something that probably resembled most + + + align:start position:0% +something that probably resembled most +closely a present day bacterium a single + + align:start position:0% +closely a present day bacterium a single + + + align:start position:0% +closely a present day bacterium a single +celled organism something like that now + + align:start position:0% +celled organism something like that now + + + align:start position:0% +celled organism something like that now +initially when life uh got started it's + + align:start position:0% +initially when life uh got started it's + + + align:start position:0% +initially when life uh got started it's +thought that there were a lot of organic + + align:start position:0% +thought that there were a lot of organic + + + align:start position:0% +thought that there were a lot of organic +chemicals that had been made as a + + align:start position:0% +chemicals that had been made as a + + + align:start position:0% +chemicals that had been made as a +consequence of lightning strikes and all + + align:start position:0% +consequence of lightning strikes and all + + + align:start position:0% +consequence of lightning strikes and all +sorts of chemistry that had happened so + + align:start position:0% +sorts of chemistry that had happened so + + + align:start position:0% +sorts of chemistry that had happened so +there was sort of a soup of some kinds + + align:start position:0% +there was sort of a soup of some kinds + + + align:start position:0% +there was sort of a soup of some kinds +of molecules could be used so probably + + align:start position:0% +of molecules could be used so probably + + + align:start position:0% +of molecules could be used so probably +these first organisms were able to + + align:start position:0% +these first organisms were able to + + + align:start position:0% +these first organisms were able to +basically use some preformed nutrients + + align:start position:0% +basically use some preformed nutrients + + + align:start position:0% +basically use some preformed nutrients +and then as the soup began to get + + align:start position:0% +and then as the soup began to get + + + align:start position:0% +and then as the soup began to get +depleted by using it they had learn to + + align:start position:0% +depleted by using it they had learn to + + + align:start position:0% +depleted by using it they had learn to +synthesize at least develop uh systems + + align:start position:0% +synthesize at least develop uh systems + + + align:start position:0% +synthesize at least develop uh systems +uh that would synthesize these building + + align:start position:0% +uh that would synthesize these building + + + align:start position:0% +uh that would synthesize these building +blocks and they also had to begin to + + align:start position:0% +blocks and they also had to begin to + + + align:start position:0% +blocks and they also had to begin to +worry about what to use as energy and so + + align:start position:0% +worry about what to use as energy and so + + + align:start position:0% +worry about what to use as energy and so +somewhere in here there something that + + align:start position:0% +somewhere in here there something that + + + align:start position:0% +somewhere in here there something that +I'll + + align:start position:0% +I'll + + + align:start position:0% +I'll +call + + align:start position:0% +call + + + align:start position:0% +call +uh in a silly way photo synthesis + + align:start position:0% +uh in a silly way photo synthesis + + + align:start position:0% +uh in a silly way photo synthesis +release number one but this was a system + + align:start position:0% +release number one but this was a system + + + align:start position:0% +release number one but this was a system +that enabled the organism to capture + + align:start position:0% +that enabled the organism to capture + + + align:start position:0% +that enabled the organism to capture +sunlight uh from energy uh energy from + + align:start position:0% +sunlight uh from energy uh energy from + + + align:start position:0% +sunlight uh from energy uh energy from +sunlight so that it wasn't now dependent + + align:start position:0% +sunlight so that it wasn't now dependent + + + align:start position:0% +sunlight so that it wasn't now dependent +on getting energy by eating some + + align:start position:0% +on getting energy by eating some + + + align:start position:0% +on getting energy by eating some +pre-formed ingredient was then able to + + align:start position:0% +pre-formed ingredient was then able to + + + align:start position:0% +pre-formed ingredient was then able to +uh take carbon dioxide and make it into + + align:start position:0% +uh take carbon dioxide and make it into + + + align:start position:0% +uh take carbon dioxide and make it into +forms that were useful of carbon that + + align:start position:0% +forms that were useful of carbon that + + + align:start position:0% +forms that were useful of carbon that +were useful for life and It produced a + + align:start position:0% +were useful for life and It produced a + + + align:start position:0% +were useful for life and It produced a +mo such as sulfur as a waste + + align:start position:0% +mo such as sulfur as a waste + + + align:start position:0% +mo such as sulfur as a waste +product there was a bit later in + + align:start position:0% +product there was a bit later in + + + align:start position:0% +product there was a bit later in +evolution somewhere in here something we + + align:start position:0% +evolution somewhere in here something we + + + align:start position:0% +evolution somewhere in here something we +might s think of as + + align:start position:0% + + + + align:start position:0% + +photosynthesis release + + align:start position:0% + + + + align:start position:0% + +two this was an improved version of + + align:start position:0% +two this was an improved version of + + + align:start position:0% +two this was an improved version of +photosynthesis it was captured more + + align:start position:0% +photosynthesis it was captured more + + + align:start position:0% +photosynthesis it was captured more +energy uh worked better uh but it + + align:start position:0% +energy uh worked better uh but it + + + align:start position:0% +energy uh worked better uh but it +developed it had a waste product which + + align:start position:0% +developed it had a waste product which + + + align:start position:0% +developed it had a waste product which +was oxygen oxygen hadn't been in our + + align:start position:0% +was oxygen oxygen hadn't been in our + + + align:start position:0% +was oxygen oxygen hadn't been in our +atmosphere and the first thing that sort + + align:start position:0% +atmosphere and the first thing that sort + + + align:start position:0% +atmosphere and the first thing that sort +of happened was that the world started + + align:start position:0% +of happened was that the world started + + + align:start position:0% +of happened was that the world started +to rust all the iron a lot of the iron + + align:start position:0% +to rust all the iron a lot of the iron + + + align:start position:0% +to rust all the iron a lot of the iron +started to interact with the oxygen and + + align:start position:0% +started to interact with the oxygen and + + + align:start position:0% +started to interact with the oxygen and +Penny will tell you that at the the base + + align:start position:0% +Penny will tell you that at the the base + + + align:start position:0% +Penny will tell you that at the the base +of the sea there are huge beds of iron + + align:start position:0% +of the sea there are huge beds of iron + + + align:start position:0% +of the sea there are huge beds of iron +oxide that came from this slow rusting + + align:start position:0% +oxide that came from this slow rusting + + + align:start position:0% +oxide that came from this slow rusting +of the earth and so it took many many uh + + align:start position:0% +of the earth and so it took many many uh + + + align:start position:0% +of the earth and so it took many many uh +years before oxygen levels started to + + align:start position:0% +years before oxygen levels started to + + + align:start position:0% +years before oxygen levels started to +rise as you know there all about it's + + align:start position:0% +rise as you know there all about it's + + + align:start position:0% +rise as you know there all about it's +about 20% of our atmosphere now even at + + align:start position:0% +about 20% of our atmosphere now even at + + + align:start position:0% +about 20% of our atmosphere now even at +this stage it was only a few percent of + + align:start position:0% +this stage it was only a few percent of + + + align:start position:0% +this stage it was only a few percent of +our um made up a few per of our + + align:start position:0% +our um made up a few per of our + + + align:start position:0% +our um made up a few per of our +atmosphere even by here in + + align:start position:0% +atmosphere even by here in + + + align:start position:0% +atmosphere even by here in +evolution um the first eukariotic cell + + align:start position:0% +evolution um the first eukariotic cell + + + align:start position:0% +evolution um the first eukariotic cell +is thought to + + align:start position:0% + + + + align:start position:0% + +have appeared + + align:start position:0% +have appeared + + + align:start position:0% +have appeared +somewhere here again it was likely a + + align:start position:0% +somewhere here again it was likely a + + + align:start position:0% +somewhere here again it was likely a +single celled organism like some of + + align:start position:0% +single celled organism like some of + + + align:start position:0% +single celled organism like some of +those pictures uh I showed you and + + align:start position:0% +those pictures uh I showed you and + + + align:start position:0% +those pictures uh I showed you and +evolution continued to go somewhere + + align:start position:0% +evolution continued to go somewhere + + + align:start position:0% +evolution continued to go somewhere +around + + align:start position:0% +around + + + align:start position:0% +around +a billion a billion years ago sex was + + align:start position:0% +a billion a billion years ago sex was + + + align:start position:0% +a billion a billion years ago sex was +evolved which enabled eukaryotic uh + + align:start position:0% +evolved which enabled eukaryotic uh + + + align:start position:0% +evolved which enabled eukaryotic uh +organisms to exchange genetic material + + align:start position:0% +organisms to exchange genetic material + + + align:start position:0% +organisms to exchange genetic material +and therefore evolve at a a faster rate + + align:start position:0% +and therefore evolve at a a faster rate + + + align:start position:0% +and therefore evolve at a a faster rate +than they could uh + + align:start position:0% +than they could uh + + + align:start position:0% +than they could uh +previously the Cambrian Period was about + + align:start position:0% +previously the Cambrian Period was about + + + align:start position:0% +previously the Cambrian Period was about +a half a billion + + align:start position:0% +a half a billion + + + align:start position:0% +a half a billion +to6 billion uh years ago and there was a + + align:start position:0% +to6 billion uh years ago and there was a + + + align:start position:0% +to6 billion uh years ago and there was a +veritable explosion of of life forms and + + align:start position:0% +veritable explosion of of life forms and + + + align:start position:0% +veritable explosion of of life forms and +you can still see in the fossil records + + align:start position:0% +you can still see in the fossil records + + + align:start position:0% +you can still see in the fossil records +how much diversity was generated at that + + align:start position:0% +how much diversity was generated at that + + + align:start position:0% +how much diversity was generated at that +point some of which went on to become + + align:start position:0% +point some of which went on to become + + + align:start position:0% +point some of which went on to become +life forms that we know and others which + + align:start position:0% +life forms that we know and others which + + + align:start position:0% +life forms that we know and others which +uh probably were more evolutionary dead + + align:start position:0% +uh probably were more evolutionary dead + + + align:start position:0% +uh probably were more evolutionary dead +ends um finally we get to the + + align:start position:0% + + + + align:start position:0% + +dinosaurs we about + + align:start position:0% +dinosaurs we about + + + align:start position:0% +dinosaurs we about +245 to 65 + + align:start position:0% +245 to 65 + + + align:start position:0% +245 to 65 +million years ago which should place + + align:start position:0% +million years ago which should place + + + align:start position:0% +million years ago which should place +them somewhere here on this uh on this + + align:start position:0% +them somewhere here on this uh on this + + + align:start position:0% +them somewhere here on this uh on this +timeline so in honor of this course I + + align:start position:0% +timeline so in honor of this course I + + + align:start position:0% +timeline so in honor of this course I +I've commissioned a uh fully uh full + + align:start position:0% +I've commissioned a uh fully uh full + + + align:start position:0% +I've commissioned a uh fully uh full +scale model here of a + + align:start position:0% + + + + align:start position:0% + +an we go um so we'll put uh our our + + align:start position:0% +an we go um so we'll put uh our our + + + align:start position:0% +an we go um so we'll put uh our our +dinosaur here if I can get him to stay + + align:start position:0% +dinosaur here if I can get him to stay + + + align:start position:0% +dinosaur here if I can get him to stay +put for a + + align:start position:0% +put for a + + + align:start position:0% +put for a +minute all right and uh at this point in + + align:start position:0% +minute all right and uh at this point in + + + align:start position:0% +minute all right and uh at this point in +evolution things started to get + + align:start position:0% +evolution things started to get + + + align:start position:0% +evolution things started to get +interesting so somewhere about here we + + align:start position:0% +interesting so somewhere about here we + + + align:start position:0% +interesting so somewhere about here we +uh four four million years ago we got + + align:start position:0% +uh four four million years ago we got + + + align:start position:0% +uh four four million years ago we got +the first evidence of of hominoids uh + + align:start position:0% +the first evidence of of hominoids uh + + + align:start position:0% +the first evidence of of hominoids uh +maybe 20 thousand years ago we found the + + align:start position:0% +maybe 20 thousand years ago we found the + + + align:start position:0% +maybe 20 thousand years ago we found the +cave paintings in in France and then + + align:start position:0% +cave paintings in in France and then + + + align:start position:0% +cave paintings in in France and then +there was the Roman Empire and Columbus + + align:start position:0% +there was the Roman Empire and Columbus + + + align:start position:0% +there was the Roman Empire and Columbus +discovered America and uh you were born + + align:start position:0% +discovered America and uh you were born + + + align:start position:0% +discovered America and uh you were born +in the Red Sox W the uh World Series and + + align:start position:0% +in the Red Sox W the uh World Series and + + + align:start position:0% +in the Red Sox W the uh World Series and +uh the Patriots have just won the Super + + align:start position:0% +uh the Patriots have just won the Super + + + align:start position:0% +uh the Patriots have just won the Super +Bowl and we are now here + + align:start position:0% +Bowl and we are now here + + + align:start position:0% +Bowl and we are now here +uh at the peak of evolution uh which is + + align:start position:0% +uh at the peak of evolution uh which is + + + align:start position:0% +uh at the peak of evolution uh which is +as you all know is the MIT student so + + align:start position:0% +as you all know is the MIT student so + + + align:start position:0% +as you all know is the MIT student so +we'll put this our MIT student here who + + align:start position:0% +we'll put this our MIT student here who + + + align:start position:0% +we'll put this our MIT student here who +I can probably not get to stay put + + align:start position:0% +I can probably not get to stay put + + + align:start position:0% +I can probably not get to stay put +because you never get MIT students to + + align:start position:0% +because you never get MIT students to + + + align:start position:0% +because you never get MIT students to +stay anywhere but any case this is sort + + align:start position:0% +stay anywhere but any case this is sort + + + align:start position:0% +stay anywhere but any case this is sort +of a silly demonstration but there's a + + align:start position:0% +of a silly demonstration but there's a + + + align:start position:0% +of a silly demonstration but there's a +very profound uh reason why I'm doing it + + align:start position:0% +very profound uh reason why I'm doing it + + + align:start position:0% +very profound uh reason why I'm doing it +and I must say I don't think I'd ever + + align:start position:0% +and I must say I don't think I'd ever + + + align:start position:0% +and I must say I don't think I'd ever +fully appreciated it until I actually + + align:start position:0% +fully appreciated it until I actually + + + align:start position:0% +fully appreciated it until I actually +thought of doing this this demo for the + + align:start position:0% +thought of doing this this demo for the + + + align:start position:0% +thought of doing this this demo for the +class but what I think you you can see + + align:start position:0% +class but what I think you you can see + + + align:start position:0% +class but what I think you you can see +is that uh Evolution for the most part + + align:start position:0% +is that uh Evolution for the most part + + + align:start position:0% +is that uh Evolution for the most part +happened at the Single Cell level many + + align:start position:0% +happened at the Single Cell level many + + + align:start position:0% +happened at the Single Cell level many +people tended to think oh Evolution that + + align:start position:0% +people tended to think oh Evolution that + + + align:start position:0% +people tended to think oh Evolution that +was about dinosaurs and all that stuff + + align:start position:0% +was about dinosaurs and all that stuff + + + align:start position:0% +was about dinosaurs and all that stuff +you can see the dinosaurs are + + align:start position:0% +you can see the dinosaurs are + + + align:start position:0% +you can see the dinosaurs are +practically now most of evolution + + align:start position:0% +practically now most of evolution + + + align:start position:0% +practically now most of evolution +occurred at the level of single cells + + align:start position:0% +occurred at the level of single cells + + + align:start position:0% +occurred at the level of single cells +that's all this amazing diversity we see + + align:start position:0% +that's all this amazing diversity we see + + + align:start position:0% +that's all this amazing diversity we see +around us was very recent uh um + + align:start position:0% +around us was very recent uh um + + + align:start position:0% +around us was very recent uh um +embellishments in evolution so that + + align:start position:0% +embellishments in evolution so that + + + align:start position:0% +embellishments in evolution so that +means that when you study biology at the + + align:start position:0% +means that when you study biology at the + + + align:start position:0% +means that when you study biology at the +cellular and molecular level you find + + align:start position:0% +cellular and molecular level you find + + + align:start position:0% +cellular and molecular level you find +tremendous commonalities if you look + + align:start position:0% +tremendous commonalities if you look + + + align:start position:0% +tremendous commonalities if you look +inside uh a sulfolobus growing in a hot + + align:start position:0% +inside uh a sulfolobus growing in a hot + + + align:start position:0% +inside uh a sulfolobus growing in a hot +spring you look inside an ecoli you look + + align:start position:0% +spring you look inside an ecoli you look + + + align:start position:0% +spring you look inside an ecoli you look +inside a yeast and you look inside one + + align:start position:0% +inside a yeast and you look inside one + + + align:start position:0% +inside a yeast and you look inside one +of our cells you find that to a huge + + align:start position:0% +of our cells you find that to a huge + + + align:start position:0% +of our cells you find that to a huge +extent uh all the cell many many of the + + align:start position:0% +extent uh all the cell many many of the + + + align:start position:0% +extent uh all the cell many many of the +cellular components are common they + + align:start position:0% +cellular components are common they + + + align:start position:0% +cellular components are common they +arose so early in evolution that they're + + align:start position:0% +arose so early in evolution that they're + + + align:start position:0% +arose so early in evolution that they're +shared by all forms of life of course + + align:start position:0% +shared by all forms of life of course + + + align:start position:0% +shared by all forms of life of course +there's some things that develop later + + align:start position:0% +there's some things that develop later + + + align:start position:0% +there's some things that develop later +and are different but that's one of the + + align:start position:0% +and are different but that's one of the + + + align:start position:0% +and are different but that's one of the +reasons that you can learn so much by + + align:start position:0% +reasons that you can learn so much by + + + align:start position:0% +reasons that you can learn so much by +studying biology at the cellular + + align:start position:0% +studying biology at the cellular + + + align:start position:0% +studying biology at the cellular +molecular level and while we'll why + + align:start position:0% +molecular level and while we'll why + + + align:start position:0% +molecular level and while we'll why +we'll emphasize it a fair bit um in this + + align:start position:0% +we'll emphasize it a fair bit um in this + + + align:start position:0% +we'll emphasize it a fair bit um in this +uh in this course the other thing that + + align:start position:0% +uh in this course the other thing that + + + align:start position:0% +uh in this course the other thing that +I'd U like to make out of this theme + + align:start position:0% +I'd U like to make out of this theme + + + align:start position:0% +I'd U like to make out of this theme +that you'll hear along is in that is + + align:start position:0% +that you'll hear along is in that is + + + align:start position:0% +that you'll hear along is in that is +that organisms U modify their + + align:start position:0% +that organisms U modify their + + + align:start position:0% +that organisms U modify their +environment you can see that in the case + + align:start position:0% +environment you can see that in the case + + + align:start position:0% +environment you can see that in the case +of oxygen back when the Earth formed uh + + align:start position:0% +of oxygen back when the Earth formed uh + + + align:start position:0% +of oxygen back when the Earth formed uh +there was no oxygen in our atmosphere + + align:start position:0% +there was no oxygen in our atmosphere + + + align:start position:0% +there was no oxygen in our atmosphere +now we have a lot of it the reason it's + + align:start position:0% +now we have a lot of it the reason it's + + + align:start position:0% +now we have a lot of it the reason it's +there is because it was generated by uh + + align:start position:0% +there is because it was generated by uh + + + align:start position:0% +there is because it was generated by uh +organisms carrying out photosynthesis + + align:start position:0% +organisms carrying out photosynthesis + + + align:start position:0% +organisms carrying out photosynthesis +and generating oxygen as a waste product + + align:start position:0% +and generating oxygen as a waste product + + + align:start position:0% +and generating oxygen as a waste product +and uh that was an absolutely critical + + align:start position:0% +and uh that was an absolutely critical + + + align:start position:0% +and uh that was an absolutely critical +thing to enable creatures such of + + align:start position:0% +thing to enable creatures such of + + + align:start position:0% +thing to enable creatures such of +ourselves which are dependent on on + + align:start position:0% +ourselves which are dependent on on + + + align:start position:0% +ourselves which are dependent on on +oxygen for our for our just to even be + + align:start position:0% +oxygen for our for our just to even be + + + align:start position:0% +oxygen for our for our just to even be +alive um if we hadn't had this change in + + align:start position:0% +alive um if we hadn't had this change in + + + align:start position:0% +alive um if we hadn't had this change in +environment uh things like us couldn't + + align:start position:0% +environment uh things like us couldn't + + + align:start position:0% +environment uh things like us couldn't +have organisms like us couldn't have + + align:start position:0% +have organisms like us couldn't have + + + align:start position:0% +have organisms like us couldn't have +evolved so anyway um I hope that will + + align:start position:0% +evolved so anyway um I hope that will + + + align:start position:0% +evolved so anyway um I hope that will +give you a little sort of snapshot of + + align:start position:0% +give you a little sort of snapshot of + + + align:start position:0% +give you a little sort of snapshot of +evolution and will help guide your + + align:start position:0% +evolution and will help guide your + + + align:start position:0% +evolution and will help guide your +understanding of this course we'll see + + align:start position:0% +understanding of this course we'll see + + + align:start position:0% +understanding of this course we'll see +you at the next lecture \ No newline at end of file diff --git a/m9AJwUCAWGQ.txt b/m9AJwUCAWGQ.txt new file mode 100644 index 0000000000000000000000000000000000000000..b7562fe5f0fa07b4d3986e6c5bee8d2a73e572c9 --- /dev/null +++ b/m9AJwUCAWGQ.txt @@ -0,0 +1,1807 @@ +The following content is +provided by MIT OpenCourseWare + +under a Creative Commons +license. + +Additional information about +our license and MIT + +OpenCourseWare in general is +available at ocw.mit.edu. + +Where were we, +last time? + +Last time, we said we were +setting aside the problem of the + +structure of the atom. +We were setting it aside + +because we were stuck, +and what we had to do was to + +look at another area of +discussion. + +And that is this wave-particle +duality of light and matter, + +because it is that discussion +that is going to give us the + +clues about how to proceed. +We are putting aside the + +discussion of the structure of +the atom all the way until next + +Wednesday, because next Monday, +I was reminded, + +is a student holiday. +[APPLAUSE] + +And so we started. +We talked about the wave-like + +properties of light. +We said that the property of + +superposition, +the fact that you can put waves + +at the same point in space and +their amplitudes add. + +Since waves have both positive +and negative amplitude, + +that means that you have +constructive and destructive + +interference. +And it is those interference + +phenomena, then, +that are evidence for wave-like + +property. +And we did the two-slit + +experiment to try to give you an +example of interference + +phenomena. +We were trying to understand + +those interference phenomena, +and did so in terms of this + +diagram here. +The interference phenomena that + +we saw was an array, +actually a row of bright spots, + +dark spots, bright spots, +dark spots. + +And we drew these semicircles +here around each one of the + +slits. +They represent a little bit of + +the wave that emanated through +those slits. + +Because those slits are small, +then, those waves emanated + +equally in all directions. +That is why these semicircles + +represent the wave maxima. +And what we discovered is that + +if we looked along this line +here, this line which led to + +this bright spot, +that all of the waves along + +this line were constructively +interfering. + +That is, we had the maximum of +the two waves at the same point + +in space, or the minimum of the +two waves at the same point in + +space. +And we noticed that everywhere + +along this line, +where we had that constructive + +interference, +the difference in the distance + +of the waves traveled was one +lambda. + +We noticed, here, +that everywhere along this line + +that led to a very bright spot, +we had constructive + +interference. +And the difference in distance + +traveled by those two waves was +two lambda. + +And, likewise, +up here, along this line, + +the difference in the distance +traveled was zero lambda. + +And from just that, +in a sense, qualitative + +observation, we drew a +conclusion. + +And that conclusion was in +order to get maximum + +constructive interference, +a condition that had obtain, + +is that the difference in the +distance traveled by the two + +waves has to be an integral +multiple of the wavelength. + +N could be 0, +1, 2, 3, etc. + +And so, the very bright spot +here that always bisects the two + +slits, since N is 0, +we call that the zero-order + +interference feature, +or the zero-order fraction + +feature. +The bright spot that is either + +to the left or to the right or +up or down of that center bright + +spot is the first-order +diffraction feature or the + +first-order interference +feature. + +And then the second bright spot +up or down from the center is a + +second-order diffraction +feature. + +And so on and so on. +And in recitation section, + +what you also should have done, +is you should have reasoned + +through what the condition was +for destructive interference. + +That is in between these bright +spots, you have dark spots as a + +result of destructive +interference. + +And that results because, +say, right here you get a dark + +spot -- +Right here at that point you + +would see the maximum of one +wave at the same point in space + +as the minimum of the other, +and so they exactly cancel. + +And so by just analyzing what +waves were destructively + +interfering, you should have +come up with a general + +expression for destructive +interference, + +of N plus one-half, +that quanity, + +times lambda. +That is your general condition + +for destructive interference, +the difference in the distance + +traveled by the two waves. +This kind of diagram here we + +are also going to see on Friday, +because this interference + +phenomenon is the property +associated with waves. + +And what we are going to do is +see this diagram again when we + +scatter electrons for particles. +We are going to see that + +particles, also, +will destructively and + +constructively interfere. +They also have wave-like + +properties. +That is what we will do on + +Friday. +We have established, + +now, the wave-like properties +of radiation, + +so I would like to move on and +talk about the evidence for the + +particle-like nature of +radiation. + +The evidence for the +particle-like nature of + +radiation comes from an effect +called the photoelectric effect. + +Shortly after Thompson +discovered the electron, + +scientists were noticing that +if you took a metal and shined + +radiation on that metal, +that indeed electrons were + +emitted. +Electrons came off. + +These were called +photoelectrons. + +However, the radiation that you +shined on the metal had to have + +a frequency nu that was greater +than or equal to some threshold + +frequency, nu nought. +That is, if you took radiation + +of some frequency here, +nu, that was less than this + +threshold frequency, +well, you did not get any + +electrons off. +Well, another way to kind of + +understand that data or that +effect is to just plot the + +number of the electrons that +come off as a function of the + +frequency of the radiation. +And so at low frequency, + +there are no electrons, +but all of a sudden you get to + +nu nought, and then electrons +start coming off. + +And no matter how high you +increase the frequency here, + +the number of electrons that +come off remains the same, + +remains constant. +And it turned out that for the + +metals that were looked at, +at that time, + +the threshold frequency, +here, was in the UV range of + +the electromagnetic spectrum. +Well, in addition to just + +measuring the number of +electrons and generally + +observing this effect, +scientists did not understand + +what was going on. +So they just started measuring + +everything they could think +about measuring. + +And one quantity that they +measured was the kinetic energy + +of these electrons that were +being emitted. + +And so you take kinetic energy +here, KE, as a function of the + +frequency. +They found that at low + +frequency, again, +there is no kinetic energy, + +because there are no electrons. +And then at some frequency, + +all of a sudden electrons +started coming off. + +And the kinetic energy of those +electrons seemed to increase + +with the frequency once past +that threshold frequency, + +nu nought. +Well, this was really another + +one of these conundrums, +here, at that time, + +because classical physics, +classical electromagnetism, + +classical physics had no way of +explaining these data. + +And, in fact, +what classical physics + +predicted is that the kinetic +energy of these electrons, + +that that kinetic energy should +have nothing to do with the + +frequency of the light. +That is, the kinetic energy was + +constant. +As you increased the frequency + +of the light, +classical physics would tell + +you that the kinetic energy +should not be affected by the + +frequency of the light. +There was nothing in the + +classical way of thinking, +classical electromagnetism that + +connected the frequency of the +light to the kind of energy, + +to the kinetic energy. +There was no way for blue light + +to make the electrons have a +larger kinetic energy, + +and for blue light to have an +effect on the kinetic energy, + +and red light to not have an +effect on the kinetic energy. + +In addition, +what classical physics + +predicted is that the kinetic +energy of the electrons should + +be dependent on the intensity of +the light. + +That is, the more and more +intense the radiation on the + +metal, the more and more kinetic +energy those electrons should + +have. +Because, after all, + +if you increase the intensity +of the light going into the + +metal, you are putting more and +more energy into it. + +That should be reflected in +just how energetic those + +electrons were picked out. +The more energy in, + +the electrons ought to come out +with larger and larger kinetic + +energy. +Of course, the observation was + +that the kinetic energy of the +electrons had nothing to do with + +the intensity of light. +The kinetic energy of the + +electrons did not increase as +you made the light brighter and + +brighter. +As you put more and more energy + +in, the kinetic energy remained +the same. + +It didn't have an effect. +This was a real conundrum here. + +The known classical physics was +making predictions really just + +contrary to what was being +observed. + +These data, here, +of the kinetic energy versus + +the frequency, +were around for a few years + +before Einstein took a look at +them in 1905, + +a hundred years ago. +And he looked at these data for + +many different metals. +Here is some data for metal A, + +for example, +and here is some data for metal + +B. +And, in both cases, + +it certainly looked like the +kinetic energy was linearly + +dependent on the frequency of +the radiation. + +But what was different for the +two different metals was the + +threshold frequency here, +nu nought. + +What Einstein did was, +he went and fitted a straight + +line to these data, +y equals mx plus b. + +And when he did that, + +and he went to calculate the +slope here, m, + +of these lines, +he thought "very interesting." + +Because the slope of those +lines was 6.626x10^-34 joule + +seconds. +The slope of those lines was + +something called Planck's +constant, h. + +You say so what? +Well, the reason he was so + +interested in this is because +just a few years earlier, + +there was a scientist by the +name of Max Planck who was + +interested in understanding what +was called the black-body + +radiation data. +What is a black-body? + +Well, let's just, +for simplicity purposes, + +think of the black-body as the +burner on an electric stove. + +What you know is that if you +turn up the voltage on that + +burner, the burner gets hot. +It increased in temperature. + +And you increase the +temperature, and sooner or + +later, that burner is glowing +bright red. + +And you increase the +temperature some more, + +and the burner is glowing a +brighter red. + +And you increase it some more, +and it is glowing orange. + +And you increase it some more, +which you shouldn't do, + +and it's glowing yellow. +And then if you could increase + +it some more, +it's glowing white. + +What is happening, +as you increase the + +temperature, is that the +radiation from that black-body, + +this is the black-body +radiation, is increasing in + +intensity. +But, more importantly, + +the frequency is getting larger +and larger. + +Dark red, bright red, +orange, yellow, + +white, those are all +frequencies. + +The frequency is shifting to +higher and higher values. + +And what was actually done at +that time is that the intensity + +of that black-body radiation, +oh, and this material is not in + +your notes, because you are not +responsible for it. + +I am just trying to make this +surprise that Einstein noticed + +about the slope. +I am just trying to put it in + +some context, +why he was so surprised and + +amazed at it. +This black-body intensity here, + +people had dispersed that +radiation and looked at the + +frequencies that were coming +off. + +This is intensity versus +frequency. + +Here is a general shape of that +intensity versus frequency. + +That was observed for some +temperature T one. + +That was a low temperature. +And then, when the temperature + +was increased and the intensity +versus frequency was observed, + +well, the frequencies generally +got higher. + +This is higher temperature. +Intensity goes up. + +And you increase the +temperature some more, + +and you get even higher +frequency. + +T three is the highest +temperature. + +And that is what the data were. +What Planck was trying to do + +was to understand the origin of +that black-body radiation. + +What he said was that in these +black-bodies, + +in these materials, +what there must be are + +oscillators that are giving off +this radiation. + +But he had another little kick +to these oscillators. + +These oscillators were giving +off radiation or energy in + +chunks, in quanta, +in particles. + +And using that idea, +plus some statistical + +mechanics, he was able to +calculate the shapes of these + +curves. +That is, he indeed got, + +for the lowest temperature +here, a curve that looked like + +this. +And for T two, + +he got a curve that looked like +this. + +And for T three, +he got a curve that looked like + +this. +He got the shape right, + +but he wanted to get the +intensity right, + +too. +What he realized he had to do + +was he essentially needed to +have a scaling factor, + +actually, in front of his +frequencies of his oscillators. + +He wanted a constant. +And so he said, + +what constant do I have to have +in order to make all of these + +data fit the observation? +That constant is Planck's + +constant, his own 6.626x10^-34 +joule seconds. + +There it is. +That is Planck's constant. + +That is it. +There is nothing deeper here. + +It is a natural constant. +It comes from our observations + +of the world, +of nature. + +That is it. +It is a fitting constant. + +And so that is why Einstein was +so amazed, here, + +when he realized this number is +the same as what comes out of + +here. +There must be something very + +fundamental about this h, +this Planck's constant. + +That is the story. +Isn't that amazing? + +What Einstein then proceeded to +do, of course, + +is to write down the equation +of the straight line that he + +just put through these data. +And so that equation is the + +kinetic energy equal to nu, +which is our x, + +h, which is the slope. +And then what he found was that + +the intercept here, +of course, is minus h times nu + +nought. +This is plus minus h times nu + +nought. +And that is the equation of a + +straight line. +Of course, he realized, + +if this is energy on this side, +boy, there better be energy on + +this side. +And so this h times nu + +better be an energy. +And since this nu was the + +frequency of the incident +radiation, therefore, + +h times nu better be the energy +of the incident radiation, + +E sub i. +That is where this expression, + +energy equals h times nu +comes from. + +Nothing more. +That is where it comes from, + +the photoelectric effect. +This was the first time that + +there was any relationship +between the frequency of the + +radiation and the energy of the +radiation. + +In classical electromagnetism, +there is no relationship + +between the frequency and the +energy. + +This was the first time in +which that relationship was + +observed. +And what this is saying is the + +following. +This is saying that you can + +have any frequency of radiation +you want, but the corresponding + +energy comes in these chunks of +h times nu. + +h is a quantization constant. +Radiation, nu, + +is continuous, +but the energy that corresponds + +to any given frequency of +radiation is h times nu. + +This E equals h times nu, +here, is thought of as a + +quantum of energy. +A particle of energy. + +A chunk of energy. +Later on, it became the photon, + +the energy of a photon. +If this h times nu here + +was an energy, +well, this h times nu nought + +also better be an energy. + +It is the threshold energy. +Let's draw an energy level + +diagram to try to understand +that. + +I am going to plot an energy +here. + +Let's draw an energy level for +an electron. + +This is an electron, +here, bound to the metal. + +And we know that it takes some +energy to rip this electron off + +of the metal. +Up here, at higher energy, + +is going to be our free +electron. + +I will just call it +electron-free, + +not bound to the metal anymore. +And the energy that is required + +to pull the electron off, +from the bound state to its + +free state, is this threshold +energy, h times nu nought. + +This threshold energy is like + +an ionization potential. +You know what the ionization + +potential is. +Just the energy required to + +pull an electron off an atom or +a molecule. + +However, when we are pulling an +electron off a chunk of a metal, + +we actually have another name +for it. + +It is called the work function. +That is just historical, + +but it is the same thing as an +ionization potential. + +And we often give it the symbol +phi. + +That threshold energy, +ionization energy for a metal, + +is the work function, +here, h times nu, + +phi. +The important point here is + +this. +In order to get an electron off + +of the metal, +what you have to have is + +energy, E sub i. +That energy E sub i has to be + +equal to at least the threshold +energy, h times nu nought. + +If you come in with energy of + +this radiation, +of this wavelength and that + +frequency, you pulled the +electron off, + +and then the electron is off +the metal and it just kind of + +stays there. +It doesn't move away. + +But you can also come in with +energy here, E sub i, + +that is greater than this work +function, than the threshold + +energy. +And you can pull the electron + +off. +But then, the electron is + +actually going to move away from +the metal, and the energy with + +which it moves away from the +metal, its kinetic energy, + +is just the incident energy +minus this threshold energy. + +It is the excess energy here. +And I am going to write it as + +the kinetic energy. +From that energy level diagram, + +this energy, +the incident energy, + +has to be equal to the work +function, h nu nought, + +plus the kinetic energy. + +Or, if I turned this around, +the kinetic energy is equal to + +the incident energy minus h nu +nought. + +The actual expression for the +energy that Einstein found, + +I just turned that equation +around. + +This is an equation that you +have to know. + +I will not give this to you on +an exam. + +Now, you don't have to memorize +it. + +You just have to reason it. +Draw yourself an energy + +diagram. +You know conservation of + +energy. +The sum of these two energies + +has to equal the incident +energy. + +Then you will be all set. +Now, what is very important + +here is the following. +If I come in with radiation + +that is, say, +a half of the threshold energy. + +Suppose I come in with two +photons, where each photon is + +one half h nu -- + +The bottom line is that you are +not going to get an electron + +off. +Even though you are coming in + +with two photons, +which together are going to + +give you the threshold energy, +you won't get a photon off. + +You have to come in with at +least the energy of the work + +function. +A photon has to have at least + +this energy to get an electron +off. + +That is the particle-like +nature of radiation. + +Energy comes in chunks, +in particles of energy, + +in quanta of energy. +Likewise, if I came in here + +with a photon that had twice the +energy of the work function or + +the threshold energy, +I would still only get one + +electron off. +I would not get two electrons + +off, even though energetically +you would be able, + +in principle, +to get two electrons off. + +But you won't. +You will only get one electron + +off. +Whenever you send a photon in, + +if it has enough energy, +that is if its energy is equal + +to or greater than the work +function, you will get an + +electron off. +There is one electron for every + +photon. +You never get two electrons for + +every photon, +or you can never get one + +electron for two photons that +are lower energy. + +That is the particle quantum +nature of radiation. + +That is important. +Yes? + +What is the form of the photon? +What do you mean by form? + +Oh, you want a picture of the +photon. + +You're looking at them. +You cannot draw a picture of a + +photon because you want to +relate it to something that is + +within your classical +experience. + +And you cannot do that. +It isn't a classical particle. + +That is what you're working +with right here. + +You are trying to use your +experiences, that are everyday + +experiences, to explain +something that isn't within your + +everyday experiences. +You don't have a frame or a + +format to do that. +Yeah? + +Yes. +If you have a constant flux of + +photons onto the surface, +you will have a constant flux + +of electrons. +Now, there is a probability. + +It is not necessarily the case +that every photon gets in, + +will eject electrons, +because there are other kinds + +of competing processes. +Whatever the rate with which + +the photons come in. +It depends on the flux of the + +photons. +And we will have some problems + +like that, where we are going to +assume that the probability of + +the electron coming off is going +to be one, so one electron for + +every photon. +But, in reality, + +there are competing processes. +Are all electrons being + +ejected? +Actually, some electrons. + +Again, this goes to the +probability. + +Some are actually kind of going +in, too, into deeper the metal. + +Not the probability, +right. + +The rate at which the electrons +come out with is dependent on + +the intensity. +The more photons you send in, + +the larger the number of +photons per second coming in, + +the larger the number of +electrons per second coming out. + +This is a plot, +here, of the energy of the + +electrons. +That's all right. + +Other questions? +Yeah? + +Eventually. +Yes. + +Absolutely. +There are other problems that + +will come in. +Usually, your light source + +isn't so energetic that you +could possibly do that. + +Now, also usually what happens +is that you've got your metal + +grounded, so that as you lose +electrons, new electrons come in + +and fill it up to the fermi +level. + +And so you don't charge up your +sample. + +In an experiment, +if you had your metal just not + +grounded and you did shine some +radiation, what would happen is + +the metal would start to charge +up. + +Then, that would make it +difficult to get electrons off. + +Yes? + +Yes. +How strongly those electrons + +are bound to the metal depends +on the electronic structure of + +the metal. +And we are going to talk a + +little bit about what determines +the strength of the interaction + +for electrons on atoms and +molecules, but it is similar to + +what it is for metals. +That is coming in a few days. + +Yes? + +Yes, there is. +Right. + +You don't actually have to have +a metal. + +You could do it. +There are usually higher + +frequencies on insulators and +semiconductors, + +right. +It is harder to see the effect, + +but it can be done and has been +done. + +Well, what I want to do right +now is to show you an experiment + +we are going to do. +We are going to do a + +photoelectron experiment. + +And the experiment is this. +We have a device up here. + +What we have is an aluminum +plate. + +And that aluminum plate is +mounted on this blue metal rod. + +And in the middle of this rod +is a needle on a pivot. + +And this is a fairly +frictionless pivot. + +This black ring, +here, is just a support + +structure, an insulating support +structure. + +What we are going to do is put +some excess charge on this + +aluminum plate. +And that excess charge is going + +to run down this metal rod and +then onto this needle. + +And because that excess charge, +the electrons on the needle and + +the electrons on the metal rod +are repulsive, + +since this is rather +frictionless, + +that needle is going to move +because of the repulsive + +interactions between these +electrons. + +What we're then going to do is +try to do the photoelectron + +experiment. +We are going to take some UV + +radiation and shine it on this +metal and drive the electrons + +off. +And we should see, + +then, the needle swing back to +its original position. + +I need a couple of volunteers +in order to do this experiment + +here. +Come on up. + +All right. +Fantastic. + +I think that is all right. +Good. + +Okay. +One of you needs to be the + +charger, and the other needs to +be the discharger. + +Which one? +You want to discharge? + +Discharge, okay. +You come over here. + +And what you are going to do is +discharge the aluminum plate + +after we get some excess charge +on it. + +You are going to do it just by +holding it up to here. + +You have to get it kind of +close because it is not a very + +intense UV source. +Could you get the video cam on + +the side or on the center to get +where we are putting it? + +I guess we are putting it on +the side, right? + +Okay. +There we go. + +There is the device. +You are the charger. + +What we are going to do, +to get the excess charge, + +we are taking a piece of +natural fur. + +We are going to rub it on this +Lucite rod. + +You have to keep your fingers +on the yellow tape here. + +And we are going to transfer +some of the natural oils here + +onto this rod. +And there are plenty of + +negative ions around here and +free electrons. + +That oil likes those negative +charges, and so there are going + +to be excess negative charges on +this Lucite rod. + +And then you are going to come +over here and just touch the + +edge of this and let the +electrons flow onto there. + +Are you right-handed? +You have to rub that really, + +really hard. +[LAUGHTER] Great. + +Go over there. +Touch the end. + +Cool. +Why don't you give it another + +jolt here and we will really +move that needle over. + +Okay. +Discharger. + +We have to give it another +jolt. + +That is okay. +You may have touched it with + +something else and discharged it +a little bit. + +No, that's okay. +You have to get the hang of + +this, here. +You are doing fantastic. + +Take it off. +That's what it is. + +You are holding it on too long. +Okay, that is pretty good. + +Put it in front there. +Get it a little bit closer. + +Here comes the UV radiation. +We did it. + +Try it again really hard. +Just touch it. + +Take it off. +Do it again. + +You need to do it again. +You've got to get it right + +here. +Not too much, + +not too little. +Okay. + +It is doing it. +Discharge in front. + +Electrons off. +Now we have to do a control + +experiment. +That is, you have got to charge + +it up again, but now, +when you put the light there, + +what I am going to do is hold +up a Pyrex plate in between the + +light and the metal. +It is going to block the + +radiation, and it should not +discharge. + +You need to get on there. +Fantastic. + +There it goes. +Here is the plate. + +Get it to a little bit lower. +Do a good discharge. + +[APPLAUSE] Fantastic. +Thank you very much. + +Thank you for being a good +sport. + +That is the photoelectron +experiment. + +Hey, it works. +Well, what I want to do now is + +just spend a few minutes working +on a few problems. + +I think these are pretty +straightforward, + +but I just want to make sure +that everybody is on the same + +page here in terms of being able +to do the homework. + +Here is the first problem. +The first problem says, + +how many photons? +And remember what we said a + +photon was? +E equals h nu. + +This is the number of joules. +Implied is the number of joules + +per photon, although we don't +usually write this, + +but that is what that is, +joules per photon. + +You may want to write it as you +do these problems. + +How many photons associated +with radiation of a wavelength + +lambda equals one picometer, +which is 1.0x10^-12 meters, + +how many of these do you need +in order to create, + +say, a laser pulse of energy +that is one joule? + +Lasers are pulsed, +so I am talking about a pulse + +of energy, one joule. +You want to draw yourself a + +picture, here. +We are drawing a picture of one + +pulse of energy, +one joule. + +Now, we have not been given the +frequency, here, + +of this radiation, +but we know the wavelength, + +and we know the relationship +between frequency and + +wavelength. +It is just c over lambda. + +I know what lambda is. +I can calculate nu. + +And, when I do that, +I find that the energy of the + +photon, hc over lambda, +that energy of the + +photon is 1.99x10^-13 joules per +photon. + +And I am using one more figure +than is significant since this + +an intermediate step in the +calculation. + +If I want a pulse of one joule +of energy and I am asked how + +many photons do I need to get +that, and each photon is + +1.99x10^-13 joules, +well, that means that I am + +going to need 5.0x10^12 photons. +There was a question here? + +All right. +Let's work another one. + +Here, we want to define what we +mean by power. + +This says the power of +radiation from the continuous + +laser is three milliwatts. + +We have some laser, +and the power of that radiation + +coming out is three milliwatts. +Well, what is power? + +Power is energy per unit time. +It is the energy delivered or + +the energy expended per unit +time. + +The unit of power that we are +going to use is a watt. + +A watt is a joule per second. +We are told that we have + +radiation of three milliwatts. +That is 3.0x10^-3 joules per + +second. +And the question asks, + +how long will it take for a +total energy of one joule to be + +supplied? +Well, one joule. + +And we have the rate of energy +supply as 3x10^-3 joules per + +second. +That gives us 330 seconds. + +That is straightforward. +Finally, we have one more. + +It says, how many photons per +second of, again, + +the same radiation, +of the wavelength of one + +picometer. +That means, again, + +we are dealing with photons +that have an energy of + +1.99x10^-13 joules per photon. +How many photons per second, + +the rate of photons at the +wavelength do you have to have, + +or do you have, +if the power of the radiation + +is three milliwatts? +Well, the power of the + +radiation is 3.0x10^-3 joules +per second, -- + +-- and we have 1.99x10^-13 +joules per photon. + +In order to have this kind of +power, what we have to have + +being emitted is 1.5x10^10 +photons per second. + +All right. +The photoelectric effect is one + +of the experiments that +demonstrated the particle-like + +nature of light, +of radiation. + +Particle-like nature because +you have to have these chunks of + +energy to make some process +occur. + +Next time, we are going to look +at and will just talk briefly + +about the other experiments that +demonstrated the particle-like + +nature of radiation. +And that other experiment is + +the demonstration that a photon +has momentum, + +even though it doesn't have any +mass. + +See you Wednesday. +See you Friday. \ No newline at end of file diff --git a/mOa1fZD9qC4.txt b/mOa1fZD9qC4.txt new file mode 100644 index 0000000000000000000000000000000000000000..bdbf30558d8a040f3bcd053be792959bbc396ca8 --- /dev/null +++ b/mOa1fZD9qC4.txt @@ -0,0 +1,2587 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT open courseware continue + + align:start position:0% +will help MIT open courseware continue + + + align:start position:0% +will help MIT open courseware continue +to offer highquality educational + + align:start position:0% +to offer highquality educational + + + align:start position:0% +to offer highquality educational +resources for free to make a donation or + + align:start position:0% +resources for free to make a donation or + + + align:start position:0% +resources for free to make a donation or +view additional materials from hundreds + + align:start position:0% +view additional materials from hundreds + + + align:start position:0% +view additional materials from hundreds +of MIT courses visit mitop courseware at + + align:start position:0% +of MIT courses visit mitop courseware at + + + align:start position:0% +of MIT courses visit mitop courseware at +ocw.mit.edu + + align:start position:0% + + + + align:start position:0% + +the inductive attenuator demonstrates + + align:start position:0% +the inductive attenuator demonstrates + + + align:start position:0% +the inductive attenuator demonstrates +the lassan nature of magnetic fields in + + align:start position:0% +the lassan nature of magnetic fields in + + + align:start position:0% +the lassan nature of magnetic fields in +free + + align:start position:0% +free + + + align:start position:0% +free +space the way that currents distribute + + align:start position:0% +space the way that currents distribute + + + align:start position:0% +space the way that currents distribute +themselves on the surfaces of perfect + + align:start position:0% +themselves on the surfaces of perfect + + + align:start position:0% +themselves on the surfaces of perfect +conductors and the use of the vector + + align:start position:0% +conductors and the use of the vector + + + align:start position:0% +conductors and the use of the vector +potential in describing magnetic fields + + align:start position:0% +potential in describing magnetic fields + + + align:start position:0% +potential in describing magnetic fields +in two-dimensional + + align:start position:0% +in two-dimensional + + + align:start position:0% +in two-dimensional +systems provided that the magnetic flux + + align:start position:0% +systems provided that the magnetic flux + + + align:start position:0% +systems provided that the magnetic flux +density is in the XY plane and Depends + + align:start position:0% +density is in the XY plane and Depends + + + align:start position:0% +density is in the XY plane and Depends +only on X and Y it can be represented by + + align:start position:0% +only on X and Y it can be represented by + + + align:start position:0% +only on X and Y it can be represented by +one component of the vector potential a + + align:start position:0% +one component of the vector potential a + + + align:start position:0% +one component of the vector potential a +subz in free space the vector potential + + align:start position:0% +subz in free space the vector potential + + + align:start position:0% +subz in free space the vector potential +satisfies llosa's + + align:start position:0% + + + + align:start position:0% + +equation separable solutions to Lassa + + align:start position:0% +equation separable solutions to Lassa + + + align:start position:0% +equation separable solutions to Lassa +equation that are periodic in One + + align:start position:0% +equation that are periodic in One + + + align:start position:0% +equation that are periodic in One +Direction decay in a perpendicular + + align:start position:0% +Direction decay in a perpendicular + + + align:start position:0% +Direction decay in a perpendicular +Direction here the direction of + + align:start position:0% +Direction here the direction of + + + align:start position:0% +Direction here the direction of +periodicity is + + align:start position:0% +periodicity is + + + align:start position:0% +periodicity is +X while the hyperbolic sign is a + + align:start position:0% +X while the hyperbolic sign is a + + + align:start position:0% +X while the hyperbolic sign is a +combination of exponentials representing + + align:start position:0% +combination of exponentials representing + + + align:start position:0% +combination of exponentials representing +the decay in the y + + align:start position:0% + + + + align:start position:0% + +direction in this model the floor is the + + align:start position:0% +direction in this model the floor is the + + + align:start position:0% +direction in this model the floor is the +XY + + align:start position:0% +XY + + + align:start position:0% +XY +plane the altitude of the surface is the + + align:start position:0% +plane the altitude of the surface is the + + + align:start position:0% +plane the altitude of the surface is the +vector + + align:start position:0% + + + + align:start position:0% + +potential here's the direction of + + align:start position:0% +potential here's the direction of + + + align:start position:0% +potential here's the direction of +periodicity here's the direction of + + align:start position:0% + + + + align:start position:0% + +Decay because it represents a solution + + align:start position:0% +Decay because it represents a solution + + + align:start position:0% +Decay because it represents a solution +to ll's equation every point on the + + align:start position:0% +to ll's equation every point on the + + + align:start position:0% +to ll's equation every point on the +surface having a positive curvature in + + align:start position:0% +surface having a positive curvature in + + + align:start position:0% +surface having a positive curvature in +the y direction must have a negative + + align:start position:0% +the y direction must have a negative + + + align:start position:0% +the y direction must have a negative +curvature in the X + + align:start position:0% +curvature in the X + + + align:start position:0% +curvature in the X +Direction This Is Why periodicity in One + + align:start position:0% +Direction This Is Why periodicity in One + + + align:start position:0% +Direction This Is Why periodicity in One +Direction implies decay in the + + align:start position:0% + + + + align:start position:0% + +other for this solution to llosa's + + align:start position:0% +other for this solution to llosa's + + + align:start position:0% +other for this solution to llosa's +equation three of the rectangular + + align:start position:0% +equation three of the rectangular + + + align:start position:0% +equation three of the rectangular +boundaries have a constant Vector + + align:start position:0% +boundaries have a constant Vector + + + align:start position:0% +boundaries have a constant Vector +potential the fourth is a + + align:start position:0% +potential the fourth is a + + + align:start position:0% +potential the fourth is a +sinusoid in our physical situation this + + align:start position:0% +sinusoid in our physical situation this + + + align:start position:0% +sinusoid in our physical situation this +fourth boundary is elevated to a uniform + + align:start position:0% +fourth boundary is elevated to a uniform + + + align:start position:0% +fourth boundary is elevated to a uniform +Vector potential + + align:start position:0% +Vector potential + + + align:start position:0% +Vector potential +this can be represented by a + + align:start position:0% +this can be represented by a + + + align:start position:0% +this can be represented by a +superposition of these + + align:start position:0% + + + + align:start position:0% + +solutions to represent a uniform Vector + + align:start position:0% +solutions to represent a uniform Vector + + + align:start position:0% +solutions to represent a uniform Vector +potential Solutions are added that have + + align:start position:0% +potential Solutions are added that have + + + align:start position:0% +potential Solutions are added that have +a shorter + + align:start position:0% +a shorter + + + align:start position:0% +a shorter +wavelength by the nature of lass's + + align:start position:0% +wavelength by the nature of lass's + + + align:start position:0% +wavelength by the nature of lass's +equation these have a more rapid Decay + + align:start position:0% +equation these have a more rapid Decay + + + align:start position:0% +equation these have a more rapid Decay +than the fundamental in the + + align:start position:0% +than the fundamental in the + + + align:start position:0% +than the fundamental in the +perpendicular y + + align:start position:0% + + + + align:start position:0% + +direction here are the magnetic flux + + align:start position:0% +direction here are the magnetic flux + + + align:start position:0% +direction here are the magnetic flux +lines represented by the Vector + + align:start position:0% +lines represented by the Vector + + + align:start position:0% +lines represented by the Vector +potential these are the boundaries where + + align:start position:0% +potential these are the boundaries where + + + align:start position:0% +potential these are the boundaries where +the vector potential is + + align:start position:0% +the vector potential is + + + align:start position:0% +the vector potential is +zero this is the boundary that is + + align:start position:0% +zero this is the boundary that is + + + align:start position:0% +zero this is the boundary that is +elevated in its Vector + + align:start position:0% +elevated in its Vector + + + align:start position:0% +elevated in its Vector +potential a surface of constant Vector + + align:start position:0% +potential a surface of constant Vector + + + align:start position:0% +potential a surface of constant Vector +potential is one that sustains no normal + + align:start position:0% +potential is one that sustains no normal + + + align:start position:0% +potential is one that sustains no normal +component of the magnetic flux + + align:start position:0% +component of the magnetic flux + + + align:start position:0% +component of the magnetic flux +density it can be the surface of a + + align:start position:0% +density it can be the surface of a + + + align:start position:0% +density it can be the surface of a +perfect + + align:start position:0% +perfect + + + align:start position:0% +perfect +conductor here these boundaries of zero + + align:start position:0% +conductor here these boundaries of zero + + + align:start position:0% +conductor here these boundaries of zero +Vector potential are perfect conductors + + align:start position:0% +Vector potential are perfect conductors + + + align:start position:0% +Vector potential are perfect conductors +carrying that surface current necessary + + align:start position:0% +carrying that surface current necessary + + + align:start position:0% +carrying that surface current necessary +to terminate the tangential magnetic + + align:start position:0% + + + + align:start position:0% + +field this boundary of elevated Vector + + align:start position:0% +field this boundary of elevated Vector + + + align:start position:0% +field this boundary of elevated Vector +potential is also a perfect + + align:start position:0% +potential is also a perfect + + + align:start position:0% +potential is also a perfect +conductor the difference between the + + align:start position:0% +conductor the difference between the + + + align:start position:0% +conductor the difference between the +vector potential on this electrode and + + align:start position:0% +vector potential on this electrode and + + + align:start position:0% +vector potential on this electrode and +on the wall is the net magnetic flux per + + align:start position:0% +on the wall is the net magnetic flux per + + + align:start position:0% +on the wall is the net magnetic flux per +unit length passing inward through the + + align:start position:0% + + + + align:start position:0% + +Gap similarly the difference between the + + align:start position:0% +Gap similarly the difference between the + + + align:start position:0% +Gap similarly the difference between the +electrode Vector potential and the wall + + align:start position:0% +electrode Vector potential and the wall + + + align:start position:0% +electrode Vector potential and the wall +potential here is the net magnetic flux + + align:start position:0% +potential here is the net magnetic flux + + + align:start position:0% +potential here is the net magnetic flux +per unit length passing out + + align:start position:0% +per unit length passing out + + + align:start position:0% +per unit length passing out +outward the surface current passing + + align:start position:0% +outward the surface current passing + + + align:start position:0% +outward the surface current passing +outward on the electrode is returned in + + align:start position:0% +outward on the electrode is returned in + + + align:start position:0% +outward on the electrode is returned in +the side + + align:start position:0% +the side + + + align:start position:0% +the side +walls and bottom + + align:start position:0% + + + + align:start position:0% + +wall in our model lines of constant + + align:start position:0% +wall in our model lines of constant + + + align:start position:0% +wall in our model lines of constant +altitude are lines of constant Vector + + align:start position:0% +altitude are lines of constant Vector + + + align:start position:0% +altitude are lines of constant Vector +potential in two Dimensions lines of + + align:start position:0% +potential in two Dimensions lines of + + + align:start position:0% +potential in two Dimensions lines of +constant a subz are lines of magnetic + + align:start position:0% +constant a subz are lines of magnetic + + + align:start position:0% +constant a subz are lines of magnetic +flux + + align:start position:0% +flux + + + align:start position:0% +flux +density so the wires are the lines of + + align:start position:0% +density so the wires are the lines of + + + align:start position:0% +density so the wires are the lines of +magnetic flux + + align:start position:0% + + + + align:start position:0% + +density if you're familiar with using a + + align:start position:0% +density if you're familiar with using a + + + align:start position:0% +density if you're familiar with using a +scalar potential to represent an + + align:start position:0% +scalar potential to represent an + + + align:start position:0% +scalar potential to represent an +irrotational electric + + align:start position:0% +irrotational electric + + + align:start position:0% +irrotational electric +field the role played by the scalar + + align:start position:0% +field the role played by the scalar + + + align:start position:0% +field the role played by the scalar +potential is being played here by the + + align:start position:0% +potential is being played here by the + + + align:start position:0% +potential is being played here by the +vector + + align:start position:0% + + + + align:start position:0% + +potential Lambda is the flux per unit + + align:start position:0% +potential Lambda is the flux per unit + + + align:start position:0% +potential Lambda is the flux per unit +length passing through the gaps at the + + align:start position:0% +length passing through the gaps at the + + + align:start position:0% +length passing through the gaps at the +ends of the top + + align:start position:0% + + + + align:start position:0% + +electrode in the Electro quas static + + align:start position:0% +electrode in the Electro quas static + + + align:start position:0% +electrode in the Electro quas static +analog this flux is analogous to the + + align:start position:0% +analog this flux is analogous to the + + + align:start position:0% +analog this flux is analogous to the +voltage between the upper electrode and + + align:start position:0% +voltage between the upper electrode and + + + align:start position:0% +voltage between the upper electrode and +the + + align:start position:0% + + + + align:start position:0% + +wall the analogy is + + align:start position:0% +wall the analogy is + + + align:start position:0% +wall the analogy is +intriguing it is the potentials that are + + align:start position:0% +intriguing it is the potentials that are + + + align:start position:0% +intriguing it is the potentials that are +analgous in the electr quasy static + + align:start position:0% +analgous in the electr quasy static + + + align:start position:0% +analgous in the electr quasy static +situation the field lines are + + align:start position:0% +situation the field lines are + + + align:start position:0% +situation the field lines are +perpendicular to the lines of constant + + align:start position:0% +perpendicular to the lines of constant + + + align:start position:0% +perpendicular to the lines of constant +scalar + + align:start position:0% + + + + align:start position:0% + +potential here in our Magneto quasy + + align:start position:0% +potential here in our Magneto quasy + + + align:start position:0% +potential here in our Magneto quasy +static situation the lines of constant + + align:start position:0% +static situation the lines of constant + + + align:start position:0% +static situation the lines of constant +Vector potential are the field + + align:start position:0% + + + + align:start position:0% + +lines although we may think of the + + align:start position:0% +lines although we may think of the + + + align:start position:0% +lines although we may think of the +fields as two-dimensional their physical + + align:start position:0% +fields as two-dimensional their physical + + + align:start position:0% +fields as two-dimensional their physical +embodiment is actually + + align:start position:0% +embodiment is actually + + + align:start position:0% +embodiment is actually +three-dimensional here's the driving + + align:start position:0% + + + + align:start position:0% + +electrode here are the + + align:start position:0% + + + + align:start position:0% + +sidewalls the current outward through + + align:start position:0% +sidewalls the current outward through + + + align:start position:0% +sidewalls the current outward through +the driven electrode + + align:start position:0% +the driven electrode + + + align:start position:0% +the driven electrode +is either returned in the side walls + + align:start position:0% +is either returned in the side walls + + + align:start position:0% +is either returned in the side walls +through connecting + + align:start position:0% +through connecting + + + align:start position:0% +through connecting +wires or is induced in the bottom + + align:start position:0% + + + + align:start position:0% + +wall the current outward through the + + align:start position:0% +wall the current outward through the + + + align:start position:0% +wall the current outward through the +driven electrode is either returned in + + align:start position:0% +driven electrode is either returned in + + + align:start position:0% +driven electrode is either returned in +the sidewalls through connecting + + align:start position:0% + + + + align:start position:0% + +wires or is induced in the bottom wall + + align:start position:0% + + + + align:start position:0% + +over any cross-section the fields are + + align:start position:0% +over any cross-section the fields are + + + align:start position:0% +over any cross-section the fields are +two- + + align:start position:0% + + + + align:start position:0% + +dimensional the closer the bottom + + align:start position:0% +dimensional the closer the bottom + + + align:start position:0% +dimensional the closer the bottom +electrode is to the driving electrode + + align:start position:0% +electrode is to the driving electrode + + + align:start position:0% +electrode is to the driving electrode +the more the current circulating through + + align:start position:0% +the more the current circulating through + + + align:start position:0% +the more the current circulating through +the bottom + + align:start position:0% + + + + align:start position:0% + +electrode the current from this 20 khz + + align:start position:0% +electrode the current from this 20 khz + + + align:start position:0% +electrode the current from this 20 khz +Source passes forward through the upper + + align:start position:0% +Source passes forward through the upper + + + align:start position:0% +Source passes forward through the upper +electrode and is returned in the + + align:start position:0% +electrode and is returned in the + + + align:start position:0% +electrode and is returned in the +sidewalls through these + + align:start position:0% + + + + align:start position:0% + +shorts so that we can measure that part + + align:start position:0% +shorts so that we can measure that part + + + align:start position:0% +shorts so that we can measure that part +of the current circulating through the + + align:start position:0% +of the current circulating through the + + + align:start position:0% +of the current circulating through the +bottom + + align:start position:0% +bottom + + + align:start position:0% +bottom +electrode it's insulated from the + + align:start position:0% +electrode it's insulated from the + + + align:start position:0% +electrode it's insulated from the +sidewalls but shorted to them at each + + align:start position:0% +sidewalls but shorted to them at each + + + align:start position:0% +sidewalls but shorted to them at each +end + + align:start position:0% + + + + align:start position:0% + +through this conductor current induced + + align:start position:0% +through this conductor current induced + + + align:start position:0% +through this conductor current induced +in the lower plate can therefore return + + align:start position:0% +in the lower plate can therefore return + + + align:start position:0% +in the lower plate can therefore return +in the + + align:start position:0% +in the + + + align:start position:0% +in the +sidewalls to complete the loop the lower + + align:start position:0% +sidewalls to complete the loop the lower + + + align:start position:0% +sidewalls to complete the loop the lower +plate is also shorted to the sidewalls + + align:start position:0% +plate is also shorted to the sidewalls + + + align:start position:0% +plate is also shorted to the sidewalls +at the far + + align:start position:0% +at the far + + + align:start position:0% +at the far +end presumably these shorts have a + + align:start position:0% +end presumably these shorts have a + + + align:start position:0% +end presumably these shorts have a +sufficiently low impedance that the + + align:start position:0% +sufficiently low impedance that the + + + align:start position:0% +sufficiently low impedance that the +lower plate remains at essentially zero + + align:start position:0% +lower plate remains at essentially zero + + + align:start position:0% +lower plate remains at essentially zero +Vector + + align:start position:0% +Vector + + + align:start position:0% +Vector +potential that is the shorts are good + + align:start position:0% +potential that is the shorts are good + + + align:start position:0% +potential that is the shorts are good +enough that little magnetic flux leaks + + align:start position:0% +enough that little magnetic flux leaks + + + align:start position:0% +enough that little magnetic flux leaks +through the + + align:start position:0% +through the + + + align:start position:0% +through the +gaps between the bottom plate and the + + align:start position:0% +gaps between the bottom plate and the + + + align:start position:0% +gaps between the bottom plate and the +sidewalls + + align:start position:0% + + + + align:start position:0% + +we'll measure the current induced in the + + align:start position:0% +we'll measure the current induced in the + + + align:start position:0% +we'll measure the current induced in the +lower plate with this current + + align:start position:0% + + + + align:start position:0% + +probe how much total current is induced + + align:start position:0% +probe how much total current is induced + + + align:start position:0% +probe how much total current is induced +in the bottom electrode for a given + + align:start position:0% +in the bottom electrode for a given + + + align:start position:0% +in the bottom electrode for a given +voltage applied to the upper + + align:start position:0% + + + + align:start position:0% + +one this is the actual + + align:start position:0% + + + + align:start position:0% + +apparatus here are the + + align:start position:0% +apparatus here are the + + + align:start position:0% +apparatus here are the +sidewalls insulated from each other + + align:start position:0% + + + + align:start position:0% + +here's the top + + align:start position:0% +here's the top + + + align:start position:0% +here's the top +plate current from this Source passes + + align:start position:0% +plate current from this Source passes + + + align:start position:0% +plate current from this Source passes +forward through the upper plate and is + + align:start position:0% +forward through the upper plate and is + + + align:start position:0% +forward through the upper plate and is +returned by the shorts through the + + align:start position:0% + + + + align:start position:0% + +sidewalls here are the connections at + + align:start position:0% +sidewalls here are the connections at + + + align:start position:0% +sidewalls here are the connections at +the back + + align:start position:0% +the back + + + align:start position:0% +the back +end the source is connected by the + + align:start position:0% +end the source is connected by the + + + align:start position:0% +end the source is connected by the +center conductor of a coaxial cable to + + align:start position:0% +center conductor of a coaxial cable to + + + align:start position:0% +center conductor of a coaxial cable to +the upper elect elod + + align:start position:0% +the upper elect elod + + + align:start position:0% +the upper elect elod +here the driving current is returned to + + align:start position:0% +here the driving current is returned to + + + align:start position:0% +here the driving current is returned to +the source by these + + align:start position:0% +the source by these + + + align:start position:0% +the source by these +wires and the coax Shield + + align:start position:0% + + + + align:start position:0% + +conductor these leads are connected to + + align:start position:0% +conductor these leads are connected to + + + align:start position:0% +conductor these leads are connected to +the top trace of our + + align:start position:0% + + + + align:start position:0% + +scope the top Trace is the driving + + align:start position:0% +scope the top Trace is the driving + + + align:start position:0% +scope the top Trace is the driving +voltage + + align:start position:0% + + + + align:start position:0% + +here at the back the bottom plate is + + align:start position:0% +here at the back the bottom plate is + + + align:start position:0% +here at the back the bottom plate is +shorted to the + + align:start position:0% + + + + align:start position:0% + +sidewalls it is also shorted at the + + align:start position:0% +sidewalls it is also shorted at the + + + align:start position:0% +sidewalls it is also shorted at the +front through these + + align:start position:0% + + + + align:start position:0% + +wires we measure the current induced in + + align:start position:0% +wires we measure the current induced in + + + align:start position:0% +wires we measure the current induced in +this electrode by means of this current + + align:start position:0% + + + + align:start position:0% + +probe the lower trace on the scope + + align:start position:0% +probe the lower trace on the scope + + + align:start position:0% +probe the lower trace on the scope +represents the output current from the + + align:start position:0% +represents the output current from the + + + align:start position:0% +represents the output current from the +probe it represents the net current + + align:start position:0% +probe it represents the net current + + + align:start position:0% +probe it represents the net current +induced in the lower + + align:start position:0% +induced in the lower + + + align:start position:0% +induced in the lower +electrode here's how the current induced + + align:start position:0% +electrode here's how the current induced + + + align:start position:0% +electrode here's how the current induced +in the lower electrode varies as the + + align:start position:0% +in the lower electrode varies as the + + + align:start position:0% +in the lower electrode varies as the +driving electrode is + + align:start position:0% + + + + align:start position:0% + +lowered as the spacing is increased + + align:start position:0% +lowered as the spacing is increased + + + align:start position:0% +lowered as the spacing is increased +again with the driving voltage + + align:start position:0% +again with the driving voltage + + + align:start position:0% +again with the driving voltage +essentially held fixed the induced + + align:start position:0% +essentially held fixed the induced + + + align:start position:0% +essentially held fixed the induced +current decreases + + align:start position:0% + + + + align:start position:0% + +as the driving electrode approaches the + + align:start position:0% +as the driving electrode approaches the + + + align:start position:0% +as the driving electrode approaches the +lower electrode it increases + + align:start position:0% + + + + align:start position:0% + +again with the electrodes this close + + align:start position:0% +again with the electrodes this close + + + align:start position:0% +again with the electrodes this close +almost all of the current in the upper + + align:start position:0% +almost all of the current in the upper + + + align:start position:0% +almost all of the current in the upper +electrode is imaged in the lower + + align:start position:0% + + + + align:start position:0% + +electrode the current in the lower + + align:start position:0% +electrode the current in the lower + + + align:start position:0% +electrode the current in the lower +electrode is the integral of the + + align:start position:0% +electrode is the integral of the + + + align:start position:0% +electrode is the integral of the +tangential magnetic field intensity over + + align:start position:0% +tangential magnetic field intensity over + + + align:start position:0% +tangential magnetic field intensity over +its + + align:start position:0% + + + + align:start position:0% + +length by the nature of this equation + + align:start position:0% +length by the nature of this equation + + + align:start position:0% +length by the nature of this equation +this field intensity becomes weaker as + + align:start position:0% +this field intensity becomes weaker as + + + align:start position:0% +this field intensity becomes weaker as +the distance between top and bottom + + align:start position:0% +the distance between top and bottom + + + align:start position:0% +the distance between top and bottom +electrodes + + align:start position:0% + + + + align:start position:0% + +increases as the distance between + + align:start position:0% +increases as the distance between + + + align:start position:0% +increases as the distance between +electrodes + + align:start position:0% +electrodes + + + align:start position:0% +electrodes +increases the fraction of the current + + align:start position:0% +increases the fraction of the current + + + align:start position:0% +increases the fraction of the current +that returns in the lower electrode is + + align:start position:0% + + + + align:start position:0% + +reduced the walls have a width w + + align:start position:0% +reduced the walls have a width w + + + align:start position:0% +reduced the walls have a width w +and are separated by + + align:start position:0% +and are separated by + + + align:start position:0% +and are separated by +a we've been adjusting the distance B + + align:start position:0% +a we've been adjusting the distance B + + + align:start position:0% +a we've been adjusting the distance B +between the exitation and detection + + align:start position:0% + + + + align:start position:0% + +plates our modal Theory tells us that + + align:start position:0% +plates our modal Theory tells us that + + + align:start position:0% +plates our modal Theory tells us that +this output current I sub Z has this + + align:start position:0% +this output current I sub Z has this + + + align:start position:0% +this output current I sub Z has this +dependence on the ac exitation voltage + + align:start position:0% +dependence on the ac exitation voltage + + + align:start position:0% +dependence on the ac exitation voltage +amplitude + + align:start position:0% +amplitude + + + align:start position:0% +amplitude +V here's the dependence on the distance + + align:start position:0% +V here's the dependence on the distance + + + align:start position:0% +V here's the dependence on the distance +between exitation and detection + + align:start position:0% +between exitation and detection + + + align:start position:0% +between exitation and detection +plates the normalizing current I is + + align:start position:0% +plates the normalizing current I is + + + align:start position:0% +plates the normalizing current I is +proportional to the driving voltage + + align:start position:0% +proportional to the driving voltage + + + align:start position:0% +proportional to the driving voltage +V and inversely proportional to the + + align:start position:0% +V and inversely proportional to the + + + align:start position:0% +V and inversely proportional to the +angular frequency + + align:start position:0% + + + + align:start position:0% + +Omega to make a quantitative comparison + + align:start position:0% +Omega to make a quantitative comparison + + + align:start position:0% +Omega to make a quantitative comparison +between what we predict and what we + + align:start position:0% +between what we predict and what we + + + align:start position:0% +between what we predict and what we +measure we need to compute the + + align:start position:0% +measure we need to compute the + + + align:start position:0% +measure we need to compute the +normalizing current + + align:start position:0% + + + + align:start position:0% + +I the measured applied voltage V is 8.2 + + align:start position:0% +I the measured applied voltage V is 8.2 + + + align:start position:0% +I the measured applied voltage V is 8.2 +molts + + align:start position:0% +molts + + + align:start position:0% +molts +Peak the W is half a + + align:start position:0% +Peak the W is half a + + + align:start position:0% +Peak the W is half a +meter and the frequency is 20 + + align:start position:0% +meter and the frequency is 20 + + + align:start position:0% +meter and the frequency is 20 +khz so in this case I is 53 + + align:start position:0% + + + + align:start position:0% + +amp with b equal to a the measured + + align:start position:0% +amp with b equal to a the measured + + + align:start position:0% +amp with b equal to a the measured +current I Sub 0 is 2.6 milliamps + + align:start position:0% +current I Sub 0 is 2.6 milliamps + + + align:start position:0% +current I Sub 0 is 2.6 milliamps +Peak so the natural log of this current + + align:start position:0% +Peak so the natural log of this current + + + align:start position:0% +Peak so the natural log of this current +normalized to I is - + + align:start position:0% + + + + align:start position:0% + +5.3 graphically this is the predicted + + align:start position:0% +5.3 graphically this is the predicted + + + align:start position:0% +5.3 graphically this is the predicted +dependence of output current on the + + align:start position:0% +dependence of output current on the + + + align:start position:0% +dependence of output current on the +distance between upper and lower + + align:start position:0% +distance between upper and lower + + + align:start position:0% +distance between upper and lower +plates the vertical axis is the natural + + align:start position:0% +plates the vertical axis is the natural + + + align:start position:0% +plates the vertical axis is the natural +log of the current in the lower + + align:start position:0% +log of the current in the lower + + + align:start position:0% +log of the current in the lower +electrode normalized to the current I + + align:start position:0% +electrode normalized to the current I + + + align:start position:0% +electrode normalized to the current I +which we just + + align:start position:0% +which we just + + + align:start position:0% +which we just +computed the horizontal axis is the + + align:start position:0% +computed the horizontal axis is the + + + align:start position:0% +computed the horizontal axis is the +distance between lower and upper + + align:start position:0% +distance between lower and upper + + + align:start position:0% +distance between lower and upper +electrodes normalized to the distance + + align:start position:0% +electrodes normalized to the distance + + + align:start position:0% +electrodes normalized to the distance +between the + + align:start position:0% + + + + align:start position:0% + +sidewalls the data point which we've + + align:start position:0% +sidewalls the data point which we've + + + align:start position:0% +sidewalls the data point which we've +just taken was for the electrode spacing + + align:start position:0% +just taken was for the electrode spacing + + + align:start position:0% +just taken was for the electrode spacing +equal to the distance between the + + align:start position:0% +equal to the distance between the + + + align:start position:0% +equal to the distance between the +sidewalls so our data point goes here + + align:start position:0% + + + + align:start position:0% + +here are some other values which we've + + align:start position:0% +here are some other values which we've + + + align:start position:0% +here are some other values which we've +measured the current I Sub Zero in the + + align:start position:0% +measured the current I Sub Zero in the + + + align:start position:0% +measured the current I Sub Zero in the +lower electrode does have the correct + + align:start position:0% +lower electrode does have the correct + + + align:start position:0% +lower electrode does have the correct +variation with spacing between the + + align:start position:0% +variation with spacing between the + + + align:start position:0% +variation with spacing between the +electrodes however it's displaced + + align:start position:0% +electrodes however it's displaced + + + align:start position:0% +electrodes however it's displaced +downward from the predicted curve by + + align:start position:0% +downward from the predicted curve by + + + align:start position:0% +downward from the predicted curve by +essentially a constant factor of eight + + align:start position:0% +essentially a constant factor of eight + + + align:start position:0% +essentially a constant factor of eight +or + + align:start position:0% + + + + align:start position:0% + +n the main main reason for this + + align:start position:0% +n the main main reason for this + + + align:start position:0% +n the main main reason for this +discrepancy is the flux linked by the + + align:start position:0% +discrepancy is the flux linked by the + + + align:start position:0% +discrepancy is the flux linked by the +wires used to provide the return current + + align:start position:0% +wires used to provide the return current + + + align:start position:0% +wires used to provide the return current +paths the rate of change of this flux + + align:start position:0% +paths the rate of change of this flux + + + align:start position:0% +paths the rate of change of this flux +makes an addition to the measured + + align:start position:0% +makes an addition to the measured + + + align:start position:0% +makes an addition to the measured +terminal voltage that makes the + + align:start position:0% +terminal voltage that makes the + + + align:start position:0% +terminal voltage that makes the +normalization current I larger than it + + align:start position:0% +normalization current I larger than it + + + align:start position:0% +normalization current I larger than it +should + + align:start position:0% +should + + + align:start position:0% +should +be to see this we can use a loop of wire + + align:start position:0% +be to see this we can use a loop of wire + + + align:start position:0% +be to see this we can use a loop of wire +rather than the terminal voltage to + + align:start position:0% +rather than the terminal voltage to + + + align:start position:0% +rather than the terminal voltage to +measure the flux through the gap between + + align:start position:0% +measure the flux through the gap between + + + align:start position:0% +measure the flux through the gap between +the upper electrode and the left + + align:start position:0% +the upper electrode and the left + + + align:start position:0% +the upper electrode and the left +wall the loop passes along the outer + + align:start position:0% +wall the loop passes along the outer + + + align:start position:0% +wall the loop passes along the outer +edge of the upper Electric + + align:start position:0% + + + + align:start position:0% + +elod and is returned just outside the + + align:start position:0% +elod and is returned just outside the + + + align:start position:0% +elod and is returned just outside the +adjacent conducting + + align:start position:0% +adjacent conducting + + + align:start position:0% +adjacent conducting +wall so arranged it links little + + align:start position:0% +wall so arranged it links little + + + align:start position:0% +wall so arranged it links little +extraneous flux at the + + align:start position:0% +extraneous flux at the + + + align:start position:0% +extraneous flux at the +ends also because it will be connected + + align:start position:0% +ends also because it will be connected + + + align:start position:0% +ends also because it will be connected +to the high impedance of the + + align:start position:0% +to the high impedance of the + + + align:start position:0% +to the high impedance of the +scope it carries a negligible current + + align:start position:0% +scope it carries a negligible current + + + align:start position:0% +scope it carries a negligible current +and so the integral of the electric + + align:start position:0% +and so the integral of the electric + + + align:start position:0% +and so the integral of the electric +field intensity around the loop which is + + align:start position:0% +field intensity around the loop which is + + + align:start position:0% +field intensity around the loop which is +the voltage at the + + align:start position:0% +the voltage at the + + + align:start position:0% +the voltage at the +terminals does not have a part due to + + align:start position:0% +terminals does not have a part due to + + + align:start position:0% +terminals does not have a part due to +the resistance of the + + align:start position:0% +the resistance of the + + + align:start position:0% +the resistance of the +loop the top Trace is the electrode + + align:start position:0% +loop the top Trace is the electrode + + + align:start position:0% +loop the top Trace is the electrode +driving + + align:start position:0% + + + + align:start position:0% + +voltage here's the terminal voltage of + + align:start position:0% +voltage here's the terminal voltage of + + + align:start position:0% +voltage here's the terminal voltage of +the + + align:start position:0% + + + + align:start position:0% + +loop with the spacing between electrodes + + align:start position:0% +loop with the spacing between electrodes + + + align:start position:0% +loop with the spacing between electrodes +equal to that between the walls the + + align:start position:0% +equal to that between the walls the + + + align:start position:0% +equal to that between the walls the +terminal voltage of the flux Loop is + + align:start position:0% +terminal voltage of the flux Loop is + + + align:start position:0% +terminal voltage of the flux Loop is +about 1.2 mols + + align:start position:0% +about 1.2 mols + + + align:start position:0% +about 1.2 mols +Peak under these same conditions the + + align:start position:0% +Peak under these same conditions the + + + align:start position:0% +Peak under these same conditions the +upper electrode ter voltage was 8.2 Mt + + align:start position:0% +upper electrode ter voltage was 8.2 Mt + + + align:start position:0% +upper electrode ter voltage was 8.2 Mt +Peak about a factor of seven + + align:start position:0% + + + + align:start position:0% + +larger this data point and others we've + + align:start position:0% +larger this data point and others we've + + + align:start position:0% +larger this data point and others we've +taken using the flux Loop rather than + + align:start position:0% +taken using the flux Loop rather than + + + align:start position:0% +taken using the flux Loop rather than +the upper electrode terminal + + align:start position:0% +the upper electrode terminal + + + align:start position:0% +the upper electrode terminal +voltage not only have the predicted + + align:start position:0% +voltage not only have the predicted + + + align:start position:0% +voltage not only have the predicted +dependence on electrode spacing but more + + align:start position:0% +dependence on electrode spacing but more + + + align:start position:0% +dependence on electrode spacing but more +nearly the predicted absolute magnitude + + align:start position:0% +nearly the predicted absolute magnitude + + + align:start position:0% +nearly the predicted absolute magnitude +as + + align:start position:0% + + + + align:start position:0% + +well the inductive attenuator has + + align:start position:0% +well the inductive attenuator has + + + align:start position:0% +well the inductive attenuator has +Illustrated the lloan nature of free + + align:start position:0% +Illustrated the lloan nature of free + + + align:start position:0% +Illustrated the lloan nature of free +space Magneto quazy static + + align:start position:0% + + + + align:start position:0% + +Fields the magnetic field induced by + + align:start position:0% +Fields the magnetic field induced by + + + align:start position:0% +Fields the magnetic field induced by +applying a voltage to the upper + + align:start position:0% +applying a voltage to the upper + + + align:start position:0% +applying a voltage to the upper +electrode decays essentially + + align:start position:0% +electrode decays essentially + + + align:start position:0% +electrode decays essentially +exponentially into the rectangular + + align:start position:0% +exponentially into the rectangular + + + align:start position:0% +exponentially into the rectangular +region bounded by the essentially + + align:start position:0% +region bounded by the essentially + + + align:start position:0% +region bounded by the essentially +perfectly conducting sidewalls and the + + align:start position:0% +perfectly conducting sidewalls and the + + + align:start position:0% +perfectly conducting sidewalls and the +bottom electrode \ No newline at end of file diff --git a/mXkPCaZUXhg.txt b/mXkPCaZUXhg.txt new file mode 100644 index 0000000000000000000000000000000000000000..e7b8ff9c2e44caa95da3727c41ea7b7034bcf14c --- /dev/null +++ b/mXkPCaZUXhg.txt @@ -0,0 +1,13099 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT OpenCourseWare continue to + + align:start position:0% +will help MIT OpenCourseWare continue to + + + align:start position:0% +will help MIT OpenCourseWare continue to +offer high quality educational resources + + align:start position:0% +offer high quality educational resources + + + align:start position:0% +offer high quality educational resources +for free + + align:start position:0% +for free + + + align:start position:0% +for free +to make a donation or to view additional + + align:start position:0% +to make a donation or to view additional + + + align:start position:0% +to make a donation or to view additional +materials from hundreds of MIT courses + + align:start position:0% +materials from hundreds of MIT courses + + + align:start position:0% +materials from hundreds of MIT courses +visit MIT opencourseware at ocw.mit.edu + + align:start position:0% + + + + align:start position:0% + +okay so today we're gonna do some really + + align:start position:0% +okay so today we're gonna do some really + + + align:start position:0% +okay so today we're gonna do some really +cool stuff having to do with + + align:start position:0% +cool stuff having to do with + + + align:start position:0% +cool stuff having to do with +non-deterministic parallel programming + + align:start position:0% +non-deterministic parallel programming + + + align:start position:0% +non-deterministic parallel programming +this is where the course starts to get + + align:start position:0% +this is where the course starts to get + + + align:start position:0% +this is where the course starts to get +hard because non determinism is really + + align:start position:0% +hard because non determinism is really + + + align:start position:0% +hard because non determinism is really +nasty we'll talk about a little bit it's + + align:start position:0% +nasty we'll talk about a little bit it's + + + align:start position:0% +nasty we'll talk about a little bit it's +really nasty parallel computing as you + + align:start position:0% +really nasty parallel computing as you + + + align:start position:0% +really nasty parallel computing as you +know is pretty easy right you know it's + + align:start position:0% +know is pretty easy right you know it's + + + align:start position:0% +know is pretty easy right you know it's +just working span easy stuff right it + + align:start position:0% +just working span easy stuff right it + + + align:start position:0% +just working span easy stuff right it +makes sense can measure these things can + + align:start position:0% +makes sense can measure these things can + + + align:start position:0% +makes sense can measure these things can +learn some skills around them and so + + align:start position:0% +learn some skills around them and so + + + align:start position:0% +learn some skills around them and so +forth but non determinism is is is nasty + + align:start position:0% +forth but non determinism is is is nasty + + + align:start position:0% +forth but non determinism is is is nasty +really nasty so first let's talk about + + align:start position:0% +really nasty so first let's talk about + + + align:start position:0% +really nasty so first let's talk about +what we mean by determinism so we say + + align:start position:0% +what we mean by determinism so we say + + + align:start position:0% +what we mean by determinism so we say +that a program is deterministic on a + + align:start position:0% +that a program is deterministic on a + + + align:start position:0% +that a program is deterministic on a +given input if every memory location is + + align:start position:0% +given input if every memory location is + + + align:start position:0% +given input if every memory location is +updated with the sequence the same + + align:start position:0% +updated with the sequence the same + + + align:start position:0% +updated with the sequence the same +sequence of values in every execution so + + align:start position:0% + + + + align:start position:0% + +the program always behaves the same and + + align:start position:0% +the program always behaves the same and + + + align:start position:0% +the program always behaves the same and +you may end up if it's a parallel + + align:start position:0% +you may end up if it's a parallel + + + align:start position:0% +you may end up if it's a parallel +program having different memory + + align:start position:0% +program having different memory + + + align:start position:0% +program having different memory +locations updated in different orders I + + align:start position:0% +locations updated in different orders I + + + align:start position:0% +locations updated in different orders I +may do a and then B versus updating B + + align:start position:0% +may do a and then B versus updating B + + + align:start position:0% +may do a and then B versus updating B +and then a but if I look at a single + + align:start position:0% +and then a but if I look at a single + + + align:start position:0% +and then a but if I look at a single +memory location a say I'm always + + align:start position:0% +memory location a say I'm always + + + align:start position:0% +memory location a say I'm always +updating a with the same sequence of + + align:start position:0% +updating a with the same sequence of + + + align:start position:0% +updating a with the same sequence of +values okay there are lots of + + align:start position:0% +values okay there are lots of + + + align:start position:0% +values okay there are lots of +definitions of determinism this is not + + align:start position:0% +definitions of determinism this is not + + + align:start position:0% +definitions of determinism this is not +the only one okay there's some where + + align:start position:0% +the only one okay there's some where + + + align:start position:0% +the only one okay there's some where +people say well it's only matters if the + + align:start position:0% +people say well it's only matters if the + + + align:start position:0% +people say well it's only matters if the +output is always the same okay and there + + align:start position:0% +output is always the same okay and there + + + align:start position:0% +output is always the same okay and there +are others where you say not only does + + align:start position:0% +are others where you say not only does + + + align:start position:0% +are others where you say not only does +it have to be the same but every right + + align:start position:0% +it have to be the same but every right + + + align:start position:0% +it have to be the same but every right +to a location has to be in the same + + align:start position:0% +to a location has to be in the same + + + align:start position:0% +to a location has to be in the same +order globally okay that turns out to be + + align:start position:0% +order globally okay that turns out to be + + + align:start position:0% +order globally okay that turns out to be +actually pretty hard because if you have + + align:start position:0% +actually pretty hard because if you have + + + align:start position:0% +actually pretty hard because if you have +parallel computing you're not going to + + align:start position:0% +parallel computing you're not going to + + + align:start position:0% +parallel computing you're not going to +get them all updated the same unless you + + align:start position:0% +get them all updated the same unless you + + + align:start position:0% +get them all updated the same unless you +only have one + + align:start position:0% +only have one + + + align:start position:0% +only have one +you know processor executing + + align:start position:0% +you know processor executing + + + align:start position:0% +you know processor executing +instructions okay and so we'll talk + + align:start position:0% +instructions okay and so we'll talk + + + align:start position:0% +instructions okay and so we'll talk +about this we'll talk a little bit more + + align:start position:0% +about this we'll talk a little bit more + + + align:start position:0% +about this we'll talk a little bit more +about this kind of thing so so why + + align:start position:0% +about this kind of thing so so why + + + align:start position:0% +about this kind of thing so so why +what's the big advantage of + + align:start position:0% + + + + align:start position:0% + +deterministic programs why should we + + align:start position:0% +deterministic programs why should we + + + align:start position:0% +deterministic programs why should we +care whether it's deterministic or + + align:start position:0% +care whether it's deterministic or + + + align:start position:0% +care whether it's deterministic or +non-deterministic sure + + align:start position:0% +non-deterministic sure + + + align:start position:0% +non-deterministic sure +it's repeatable okay so what + + align:start position:0% +it's repeatable okay so what + + + align:start position:0% +it's repeatable okay so what +[Music] + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +why is that + + align:start position:0% + + + + align:start position:0% + +because sometimes that's what you want + + align:start position:0% +because sometimes that's what you want + + + align:start position:0% +because sometimes that's what you want +okay that doesn't say okay so if I mean + + align:start position:0% +okay that doesn't say okay so if I mean + + + align:start position:0% +okay that doesn't say okay so if I mean +there's a lot of things I might + + align:start position:0% +there's a lot of things I might + + + align:start position:0% +there's a lot of things I might +sometimes want how why is that important + + align:start position:0% +sometimes want how why is that important + + + align:start position:0% +sometimes want how why is that important +to want that yeah yeah makes it easier + + align:start position:0% +to want that yeah yeah makes it easier + + + align:start position:0% +to want that yeah yeah makes it easier +to debug that's probably the number one + + align:start position:0% +to debug that's probably the number one + + + align:start position:0% +to debug that's probably the number one +reason debugging okay if it does the + + align:start position:0% +reason debugging okay if it does the + + + align:start position:0% +reason debugging okay if it does the +same thing every time right then if you + + align:start position:0% +same thing every time right then if you + + + align:start position:0% +same thing every time right then if you +have a bug you can run it again you + + align:start position:0% +have a bug you can run it again you + + + align:start position:0% +have a bug you can run it again you +expect to see the bug again right so + + align:start position:0% +expect to see the bug again right so + + + align:start position:0% +expect to see the bug again right so +every time you run through hey I get the + + align:start position:0% +every time you run through hey I get the + + + align:start position:0% +every time you run through hey I get the +same bug okay but if it's + + align:start position:0% +same bug okay but if it's + + + align:start position:0% +same bug okay but if it's +non-deterministic I get a bug and now I + + align:start position:0% +non-deterministic I get a bug and now I + + + align:start position:0% +non-deterministic I get a bug and now I +go to look for it and the bug is nowhere + + align:start position:0% +go to look for it and the bug is nowhere + + + align:start position:0% +go to look for it and the bug is nowhere +to be found + + align:start position:0% +to be found + + + align:start position:0% +to be found +makes debugging a lot harder there are + + align:start position:0% +makes debugging a lot harder there are + + + align:start position:0% +makes debugging a lot harder there are +other reasons for wanting repeatability + + align:start position:0% +other reasons for wanting repeatability + + + align:start position:0% +other reasons for wanting repeatability +so your answer is actually a broader + + align:start position:0% +so your answer is actually a broader + + + align:start position:0% +so your answer is actually a broader +correct answer but but the the big + + align:start position:0% +correct answer but but the the big + + + align:start position:0% +correct answer but but the the big +advantage is in the specific application + + align:start position:0% +advantage is in the specific application + + + align:start position:0% +advantage is in the specific application +of repeatability to debugging okay so + + align:start position:0% +of repeatability to debugging okay so + + + align:start position:0% +of repeatability to debugging okay so +here's the golden rule of parallel + + align:start position:0% +here's the golden rule of parallel + + + align:start position:0% +here's the golden rule of parallel +programming okay + + align:start position:0% +programming okay + + + align:start position:0% +programming okay +never write non-deterministic parallel + + align:start position:0% +never write non-deterministic parallel + + + align:start position:0% +never write non-deterministic parallel +programs okay they can exhibit anomalous + + align:start position:0% +programs okay they can exhibit anomalous + + + align:start position:0% +programs okay they can exhibit anomalous +behaviors and it's hard to debug them + + align:start position:0% +behaviors and it's hard to debug them + + + align:start position:0% +behaviors and it's hard to debug them +okay so never ever write + + align:start position:0% +okay so never ever write + + + align:start position:0% +okay so never ever write +non-deterministic programs unfortunately + + align:start position:0% +non-deterministic programs unfortunately + + + align:start position:0% +non-deterministic programs unfortunately +this is one of these things that is kind + + align:start position:0% +this is one of these things that is kind + + + align:start position:0% +this is one of these things that is kind +of hard in practice to do so why might + + align:start position:0% +of hard in practice to do so why might + + + align:start position:0% +of hard in practice to do so why might +you want to write a non-deterministic + + align:start position:0% +you want to write a non-deterministic + + + align:start position:0% +you want to write a non-deterministic +program even though even when famous + + align:start position:0% + + + + align:start position:0% + +masters in the area of performance + + align:start position:0% +masters in the area of performance + + + align:start position:0% +masters in the area of performance +engineering okay with with highly + + align:start position:0% +engineering okay with with highly + + + align:start position:0% +engineering okay with with highly +credentialed you know numerous awards + + align:start position:0% +credentialed you know numerous awards + + + align:start position:0% +credentialed you know numerous awards +and so forth tell you you shouldn't + + align:start position:0% +and so forth tell you you shouldn't + + + align:start position:0% +and so forth tell you you shouldn't +write non-deterministic programs why + + align:start position:0% +write non-deterministic programs why + + + align:start position:0% +write non-deterministic programs why +might you want to do it anyway + + align:start position:0% + + + + align:start position:0% + +yeah yeah you might get better + + align:start position:0% +yeah yeah you might get better + + + align:start position:0% +yeah yeah you might get better +performance that's a that's one of the + + align:start position:0% +performance that's a that's one of the + + + align:start position:0% +performance that's a that's one of the +big ones that's one of the big ones and + + align:start position:0% +big ones that's one of the big ones and + + + align:start position:0% +big ones that's one of the big ones and +sometimes you can't + + align:start position:0% +sometimes you can't + + + align:start position:0% +sometimes you can't +okay the nature of the problem is maybe + + align:start position:0% +okay the nature of the problem is maybe + + + align:start position:0% +okay the nature of the problem is maybe +that it's that it's non determinacy you + + align:start position:0% +that it's that it's non determinacy you + + + align:start position:0% +that it's that it's non determinacy you +may have asynchronous inputs coming in + + align:start position:0% +may have asynchronous inputs coming in + + + align:start position:0% +may have asynchronous inputs coming in +and so forth so so this is the Golden + + align:start position:0% +and so forth so so this is the Golden + + + align:start position:0% +and so forth so so this is the Golden +Rule we also have a silver rule silver + + align:start position:0% +Rule we also have a silver rule silver + + + align:start position:0% +Rule we also have a silver rule silver +rule says never write non-deterministic + + align:start position:0% +rule says never write non-deterministic + + + align:start position:0% +rule says never write non-deterministic +parallel programs but if you must always + + align:start position:0% +parallel programs but if you must always + + + align:start position:0% +parallel programs but if you must always +devise a test strategy to manage the non + + align:start position:0% +devise a test strategy to manage the non + + + align:start position:0% +devise a test strategy to manage the non +determinism okay so this gets into you + + align:start position:0% +determinism okay so this gets into you + + + align:start position:0% +determinism okay so this gets into you +better have some way of handling how + + align:start position:0% +better have some way of handling how + + + align:start position:0% +better have some way of handling how +you're gonna tell what's going on if you + + align:start position:0% +you're gonna tell what's going on if you + + + align:start position:0% +you're gonna tell what's going on if you +have a bug okay so what are some of the + + align:start position:0% +have a bug okay so what are some of the + + + align:start position:0% +have a bug okay so what are some of the +typical test strategies that you could + + align:start position:0% +typical test strategies that you could + + + align:start position:0% +typical test strategies that you could +use that would manage the non + + align:start position:0% +use that would manage the non + + + align:start position:0% +use that would manage the non +determinism okay so imagine you've got a + + align:start position:0% +determinism okay so imagine you've got a + + + align:start position:0% +determinism okay so imagine you've got a +parallel program and it's it's got races + + align:start position:0% +parallel program and it's it's got races + + + align:start position:0% +parallel program and it's it's got races +in it and so forth + + align:start position:0% +in it and so forth + + + align:start position:0% +in it and so forth +you know and its operating + + align:start position:0% +you know and its operating + + + align:start position:0% +you know and its operating +non-deterministically what and that's + + align:start position:0% +non-deterministically what and that's + + + align:start position:0% +non-deterministically what and that's +okay if it's everything's going right + + align:start position:0% +okay if it's everything's going right + + + align:start position:0% +okay if it's everything's going right +how would you you find a bug in the + + align:start position:0% +how would you you find a bug in the + + + align:start position:0% +how would you you find a bug in the +program how are you what are you going + + align:start position:0% +program how are you what are you going + + + align:start position:0% +program how are you what are you going +to do + + align:start position:0% + + + + align:start position:0% + +what kinds of ideas do you have yeah + + align:start position:0% +what kinds of ideas do you have yeah + + + align:start position:0% +what kinds of ideas do you have yeah +[Music] + + align:start position:0% + + + + align:start position:0% + +yeah you could turn off the + + align:start position:0% +yeah you could turn off the + + + align:start position:0% +yeah you could turn off the +non-determinism okay you put a switch in + + align:start position:0% +non-determinism okay you put a switch in + + + align:start position:0% +non-determinism okay you put a switch in +there that says well I know the source + + align:start position:0% +there that says well I know the source + + + align:start position:0% +there that says well I know the source +of this non-deterministic behavior let + + align:start position:0% +of this non-deterministic behavior let + + + align:start position:0% +of this non-deterministic behavior let +me do that let me give you an example of + + align:start position:0% +me do that let me give you an example of + + + align:start position:0% +me do that let me give you an example of +that for security reasons these days + + align:start position:0% +that for security reasons these days + + + align:start position:0% +that for security reasons these days +when you allocate memory its allocated + + align:start position:0% +when you allocate memory its allocated + + + align:start position:0% +when you allocate memory its allocated +to different locations on different runs + + align:start position:0% +to different locations on different runs + + + align:start position:0% +to different locations on different runs +of the program its allocated in random + + align:start position:0% +of the program its allocated in random + + + align:start position:0% +of the program its allocated in random +places they want to randomize the + + align:start position:0% +places they want to randomize the + + + align:start position:0% +places they want to randomize the +addresses when you call malloc okay that + + align:start position:0% +addresses when you call malloc okay that + + + align:start position:0% +addresses when you call malloc okay that +means that you can end up with different + + align:start position:0% +means that you can end up with different + + + align:start position:0% +means that you can end up with different +behaviors okay from one to run and that + + align:start position:0% +behaviors okay from one to run and that + + + align:start position:0% +behaviors okay from one to run and that +can compromise your your performance but + + align:start position:0% +can compromise your your performance but + + + align:start position:0% +can compromise your your performance but +there turns out that there is a compiler + + align:start position:0% +there turns out that there is a compiler + + + align:start position:0% +there turns out that there is a compiler +switch and if you run it in debug mode + + align:start position:0% +switch and if you run it in debug mode + + + align:start position:0% +switch and if you run it in debug mode +it'll always deliver the the results of + + align:start position:0% +it'll always deliver the the results of + + + align:start position:0% +it'll always deliver the the results of +malloc in in deterministic locations + + align:start position:0% +malloc in in deterministic locations + + + align:start position:0% +malloc in in deterministic locations +okay where the locations the of the + + align:start position:0% +okay where the locations the of the + + + align:start position:0% +okay where the locations the of the +things your mouth looking are you know + + align:start position:0% +things your mouth looking are you know + + + align:start position:0% +things your mouth looking are you know +are repeatable okay so that's that's + + align:start position:0% +are repeatable okay so that's that's + + + align:start position:0% +are repeatable okay so that's that's +good okay because there's support they + + align:start position:0% +good okay because there's support they + + + align:start position:0% +good okay because there's support they +said yes we have to randomize okay for + + align:start position:0% +said yes we have to randomize okay for + + + align:start position:0% +said yes we have to randomize okay for +security reasons so that people can't + + align:start position:0% +security reasons so that people can't + + + align:start position:0% +security reasons so that people can't +deterministically exploit buffer + + align:start position:0% +deterministically exploit buffer + + + align:start position:0% +deterministically exploit buffer +overflow errors for example but you know + + align:start position:0% +overflow errors for example but you know + + + align:start position:0% +overflow errors for example but you know +I don't want to have to do that every + + align:start position:0% +I don't want to have to do that every + + + align:start position:0% +I don't want to have to do that every +time okay so you know I I don't want to + + align:start position:0% +time okay so you know I I don't want to + + + align:start position:0% +time okay so you know I I don't want to +randomize you know every time I run I + + align:start position:0% +randomize you know every time I run I + + + align:start position:0% +randomize you know every time I run I +won't have the option of making it so + + align:start position:0% +won't have the option of making it so + + + align:start position:0% +won't have the option of making it so +that that randomization is turned off + + align:start position:0% +that that randomization is turned off + + + align:start position:0% +that that randomization is turned off +okay so that's a good one + + align:start position:0% +okay so that's a good one + + + align:start position:0% +okay so that's a good one +what's another one that that can be done + + align:start position:0% + + + + align:start position:0% + +you're full of good ideas this is like + + align:start position:0% +you're full of good ideas this is like + + + align:start position:0% +you're full of good ideas this is like +let's try somebody else or not okay + + align:start position:0% +let's try somebody else or not okay + + + align:start position:0% +let's try somebody else or not okay +that's good I like that I like that what + + align:start position:0% +that's good I like that I like that what + + + align:start position:0% +that's good I like that I like that what +are some other ideas what else can you + + align:start position:0% +are some other ideas what else can you + + + align:start position:0% +are some other ideas what else can you +do to handle non determinism okay you + + align:start position:0% +do to handle non determinism okay you + + + align:start position:0% +do to handle non determinism okay you +got a program and it's yeah yeah yeah + + align:start position:0% +got a program and it's yeah yeah yeah + + + align:start position:0% +got a program and it's yeah yeah yeah +yeah if you have random numbers you use + + align:start position:0% +yeah if you have random numbers you use + + + align:start position:0% +yeah if you have random numbers you use +the same seed in some sense that's a + + align:start position:0% +the same seed in some sense that's a + + + align:start position:0% +the same seed in some sense that's a +kind of of same thing if you're turning + + align:start position:0% +kind of of same thing if you're turning + + + align:start position:0% +kind of of same thing if you're turning +off non determinism okay but that's a + + align:start position:0% +off non determinism okay but that's a + + + align:start position:0% +off non determinism okay but that's a +great one you know there are other + + align:start position:0% +great one you know there are other + + + align:start position:0% +great one you know there are other +places for example if you read you know + + align:start position:0% +places for example if you read you know + + + align:start position:0% +places for example if you read you know +if you do get time of day you know for + + align:start position:0% +if you do get time of day you know for + + + align:start position:0% +if you do get time of day you know for +something in your program for something + + align:start position:0% +something in your program for something + + + align:start position:0% +something in your program for something +you could have an option where it'll put + + align:start position:0% +you could have an option where it'll put + + + align:start position:0% +you could have an option where it'll put +in a particular fixed value there so you + + align:start position:0% +in a particular fixed value there so you + + + align:start position:0% +in a particular fixed value there so you +can make sure that it doesn't you know + + align:start position:0% +can make sure that it doesn't you know + + + align:start position:0% +can make sure that it doesn't you know +even a serial program isn't + + align:start position:0% +even a serial program isn't + + + align:start position:0% +even a serial program isn't +non-deterministic okay so that's good + + align:start position:0% +non-deterministic okay so that's good + + + align:start position:0% +non-deterministic okay so that's good +but I also consider that to be that's + + align:start position:0% +but I also consider that to be that's + + + align:start position:0% +but I also consider that to be that's +another great example of turning off non + + align:start position:0% +another great example of turning off non + + + align:start position:0% +another great example of turning off non +determinism okay what other things can + + align:start position:0% +determinism okay what other things can + + + align:start position:0% +determinism okay what other things can +you do yeah + + align:start position:0% +you do yeah + + + align:start position:0% +you do yeah +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +ah yep you can do record replay for some + + align:start position:0% +ah yep you can do record replay for some + + + align:start position:0% +ah yep you can do record replay for some +things is that what you're saying is + + align:start position:0% +things is that what you're saying is + + + align:start position:0% +things is that what you're saying is +that what you mean or am i okay so + + align:start position:0% +that what you mean or am i okay so + + + align:start position:0% +that what you mean or am i okay so +record replay says you run it through + + align:start position:0% +record replay says you run it through + + + align:start position:0% +record replay says you run it through +you can run it through with random + + align:start position:0% +you can run it through with random + + + align:start position:0% +you can run it through with random +numbers and then but it's recording + + align:start position:0% +numbers and then but it's recording + + + align:start position:0% +numbers and then but it's recording +those things so that when you when you + + align:start position:0% +those things so that when you when you + + + align:start position:0% +those things so that when you when you +run it again you can instead of using + + align:start position:0% +run it again you can instead of using + + + align:start position:0% +run it again you can instead of using +the random numbers that you you know new + + align:start position:0% +the random numbers that you you know new + + + align:start position:0% +the random numbers that you you know new +random numbers it uses the ones that you + + align:start position:0% +random numbers it uses the ones that you + + + align:start position:0% +random numbers it uses the ones that you +used to use okay so that's a record + + align:start position:0% +used to use okay so that's a record + + + align:start position:0% +used to use okay so that's a record +replay thing is that what you're saying + + align:start position:0% +replay thing is that what you're saying + + + align:start position:0% +replay thing is that what you're saying +are you saying something else yeah okay + + align:start position:0% +are you saying something else yeah okay + + + align:start position:0% +are you saying something else yeah okay +good + + align:start position:0% +good + + + align:start position:0% +good +okay so this so that's using using some + + align:start position:0% +okay so this so that's using using some + + + align:start position:0% +okay so this so that's using using some +tools there's actually a lot of + + align:start position:0% +tools there's actually a lot of + + + align:start position:0% +tools there's actually a lot of +strategies let me just move on in answer + + align:start position:0% +strategies let me just move on in answer + + + align:start position:0% +strategies let me just move on in answer +so another thing you can do is + + align:start position:0% +so another thing you can do is + + + align:start position:0% +so another thing you can do is +encapsulate the non-determinism so + + align:start position:0% +encapsulate the non-determinism so + + + align:start position:0% +encapsulate the non-determinism so +that's actually done in the silk runtime + + align:start position:0% +that's actually done in the silk runtime + + + align:start position:0% +that's actually done in the silk runtime +system already the runtime system is + + align:start position:0% +system already the runtime system is + + + align:start position:0% +system already the runtime system is +using a random scheduling strategy but + + align:start position:0% +using a random scheduling strategy but + + + align:start position:0% +using a random scheduling strategy but +you don't see that it's random in the + + align:start position:0% +you don't see that it's random in the + + + align:start position:0% +you don't see that it's random in the +execution of your code if you don't if + + align:start position:0% +execution of your code if you don't if + + + align:start position:0% +execution of your code if you don't if +you have no race conditions in your code + + align:start position:0% +you have no race conditions in your code + + + align:start position:0% +you have no race conditions in your code +its encapsulated okay so that so that + + align:start position:0% +its encapsulated okay so that so that + + + align:start position:0% +its encapsulated okay so that so that +the you know in the platform so the + + align:start position:0% +the you know in the platform so the + + + align:start position:0% +the you know in the platform so the +platform is going to guarantee you + + align:start position:0% +platform is going to guarantee you + + + align:start position:0% +platform is going to guarantee you +deterministic results even though + + align:start position:0% +deterministic results even though + + + align:start position:0% +deterministic results even though +underneath the covers it's doing + + align:start position:0% +underneath the covers it's doing + + + align:start position:0% +underneath the covers it's doing +non-deterministic things okay you can + + align:start position:0% +non-deterministic things okay you can + + + align:start position:0% +non-deterministic things okay you can +also substitute a deterministic + + align:start position:0% +also substitute a deterministic + + + align:start position:0% +also substitute a deterministic +alternative okay sometimes there's + + align:start position:0% +alternative okay sometimes there's + + + align:start position:0% +alternative okay sometimes there's +there's a way of computing something + + align:start position:0% +there's a way of computing something + + + align:start position:0% +there's a way of computing something +that is non-deterministic but in debug + + align:start position:0% +that is non-deterministic but in debug + + + align:start position:0% +that is non-deterministic but in debug +mode let me not use the + + align:start position:0% +mode let me not use the + + + align:start position:0% +mode let me not use the +non-deterministic one okay and you can + + align:start position:0% +non-deterministic one okay and you can + + + align:start position:0% +non-deterministic one okay and you can +also use analysis tools which can tell + + align:start position:0% +also use analysis tools which can tell + + + align:start position:0% +also use analysis tools which can tell +you things about your program and which + + align:start position:0% +you things about your program and which + + + align:start position:0% +you things about your program and which +you can can control things so there's a + + align:start position:0% +you can can control things so there's a + + + align:start position:0% +you can can control things so there's a +lot of things so whenever you have a + + align:start position:0% +lot of things so whenever you have a + + + align:start position:0% +lot of things so whenever you have a +non-deterministic program you want to + + align:start position:0% +non-deterministic program you want to + + + align:start position:0% +non-deterministic program you want to +find some way of controlling and often + + align:start position:0% +find some way of controlling and often + + + align:start position:0% +find some way of controlling and often +the non determinism is over in this + + align:start position:0% +the non determinism is over in this + + + align:start position:0% +the non determinism is over in this +corner but your bug is over in this + + align:start position:0% +corner but your bug is over in this + + + align:start position:0% +corner but your bug is over in this +corner so if you can turn this thing off + + align:start position:0% +corner so if you can turn this thing off + + + align:start position:0% +corner so if you can turn this thing off +in some way or encapsulate it or you + + align:start position:0% +in some way or encapsulate it or you + + + align:start position:0% +in some way or encapsulate it or you +know otherwise control the non + + align:start position:0% +know otherwise control the non + + + align:start position:0% +know otherwise control the non +determinism over there now you have a + + align:start position:0% +determinism over there now you have a + + + align:start position:0% +determinism over there now you have a +better chance of catching the stuff over + + align:start position:0% +better chance of catching the stuff over + + + align:start position:0% +better chance of catching the stuff over +here + + align:start position:0% +here + + + align:start position:0% +here +okay that's going to be particularly + + align:start position:0% +okay that's going to be particularly + + + align:start position:0% +okay that's going to be particularly +important in project four when we get to + + align:start position:0% +important in project four when we get to + + + align:start position:0% +important in project four when we get to +it + + align:start position:0% +it + + + align:start position:0% +it +because that's going to be actually + + align:start position:0% +because that's going to be actually + + + align:start position:0% +because that's going to be actually +going to be doing non-deterministic + + align:start position:0% +going to be doing non-deterministic + + + align:start position:0% +going to be doing non-deterministic +programming for a game playing program + + align:start position:0% +programming for a game playing program + + + align:start position:0% +programming for a game playing program +and one of the one of the things is that + + align:start position:0% +and one of the one of the things is that + + + align:start position:0% +and one of the one of the things is that +the processors are in this case keeping + + align:start position:0% +the processors are in this case keeping + + + align:start position:0% +the processors are in this case keeping +the game positions together and so the + + align:start position:0% +the game positions together and so the + + + align:start position:0% +the game positions together and so the +if one processor stores something into a + + align:start position:0% +if one processor stores something into a + + + align:start position:0% +if one processor stores something into a +into what's called the transposition + + align:start position:0% +into what's called the transposition + + + align:start position:0% +into what's called the transposition +table which is a essentially a big hash + + align:start position:0% +table which is a essentially a big hash + + + align:start position:0% +table which is a essentially a big hash +table of positions at scene another one + + align:start position:0% +table of positions at scene another one + + + align:start position:0% +table of positions at scene another one +can see that value and change its + + align:start position:0% +can see that value and change its + + + align:start position:0% +can see that value and change its +behavior and so one of the things you + + align:start position:0% +behavior and so one of the things you + + + align:start position:0% +behavior and so one of the things you +want to be able do is turn off + + align:start position:0% +want to be able do is turn off + + + align:start position:0% +want to be able do is turn off +transposition table okay so that so that + + align:start position:0% +transposition table okay so that so that + + + align:start position:0% +transposition table okay so that so that +you don't take advantage that + + align:start position:0% +you don't take advantage that + + + align:start position:0% +you don't take advantage that +performance advantage but now you can + + align:start position:0% +performance advantage but now you can + + + align:start position:0% +performance advantage but now you can +debug the search code or you can debug + + align:start position:0% +debug the search code or you can debug + + + align:start position:0% +debug the search code or you can debug +the evaluation code and so forth you can + + align:start position:0% +the evaluation code and so forth you can + + + align:start position:0% +the evaluation code and so forth you can +also do things like you know unit + + align:start position:0% +also do things like you know unit + + + align:start position:0% +also do things like you know unit +testing so you know whether or not a + + align:start position:0% +testing so you know whether or not a + + + align:start position:0% +testing so you know whether or not a +particular piece is correct that might + + align:start position:0% +particular piece is correct that might + + + align:start position:0% +particular piece is correct that might +have you know so that so that you can + + align:start position:0% +have you know so that so that you can + + + align:start position:0% +have you know so that so that you can +test this thing separately from the rest + + align:start position:0% +test this thing separately from the rest + + + align:start position:0% +test this thing separately from the rest +of your system which may have non + + align:start position:0% +of your system which may have non + + + align:start position:0% +of your system which may have non +determinism and way this is a major + + align:start position:0% +determinism and way this is a major + + + align:start position:0% +determinism and way this is a major +thing so so you never write them but if + + align:start position:0% +thing so so you never write them but if + + + align:start position:0% +thing so so you never write them but if +you have to you always want to have some + + align:start position:0% +you have to you always want to have some + + + align:start position:0% +you have to you always want to have some +test strategy okay and so for the people + + align:start position:0% +test strategy okay and so for the people + + + align:start position:0% +test strategy okay and so for the people +who are not watching this video and who + + align:start position:0% +who are not watching this video and who + + + align:start position:0% +who are not watching this video and who +are you know not in class today they are + + align:start position:0% +are you know not in class today they are + + + align:start position:0% +are you know not in class today they are +going to be sorely hampered by not + + align:start position:0% +going to be sorely hampered by not + + + align:start position:0% +going to be sorely hampered by not +knowing this lesson when they go into + + align:start position:0% +knowing this lesson when they go into + + + align:start position:0% +knowing this lesson when they go into +the fourth project okay so so what we're + + align:start position:0% +the fourth project okay so so what we're + + + align:start position:0% +the fourth project okay so so what we're +gonna do is now we're going to talk + + align:start position:0% +gonna do is now we're going to talk + + + align:start position:0% +gonna do is now we're going to talk +about how to do non-deterministic + + align:start position:0% +about how to do non-deterministic + + + align:start position:0% +about how to do non-deterministic +programming okay so this is you know + + align:start position:0% +programming okay so this is you know + + + align:start position:0% +programming okay so this is you know +there's always there's always some part + + align:start position:0% +there's always there's always some part + + + align:start position:0% +there's always there's always some part +of your code you know which has a skull + + align:start position:0% +of your code you know which has a skull + + + align:start position:0% +of your code you know which has a skull +and crossbones + + align:start position:0% +and crossbones + + + align:start position:0% +and crossbones +like you know you have this abstraction + + align:start position:0% +like you know you have this abstraction + + + align:start position:0% +like you know you have this abstraction +it's beautiful and you can design etc + + align:start position:0% +it's beautiful and you can design etc + + + align:start position:0% +it's beautiful and you can design etc +and then somewhere there's this really + + align:start position:0% +and then somewhere there's this really + + + align:start position:0% +and then somewhere there's this really +ugly thing that nobody should know and + + align:start position:0% +ugly thing that nobody should know and + + + align:start position:0% +ugly thing that nobody should know and +you put the skull and crossbones on that + + align:start position:0% +you put the skull and crossbones on that + + + align:start position:0% +you put the skull and crossbones on that +and only experts go in well anyway + + align:start position:0% +and only experts go in well anyway + + + align:start position:0% +and only experts go in well anyway +that's the that's the barrier we're + + align:start position:0% +that's the that's the barrier we're + + + align:start position:0% +that's the that's the barrier we're +crossing here okay and we're going to + + align:start position:0% +crossing here okay and we're going to + + + align:start position:0% +crossing here okay and we're going to +start out by talking about something + + align:start position:0% +start out by talking about something + + + align:start position:0% +start out by talking about something +that you've probably seen in + + align:start position:0% +that you've probably seen in + + + align:start position:0% +that you've probably seen in +your other classes mutual exclusion and + + align:start position:0% +your other classes mutual exclusion and + + + align:start position:0% +your other classes mutual exclusion and +atomicity so I'm going to use the + + align:start position:0% +atomicity so I'm going to use the + + + align:start position:0% +atomicity so I'm going to use the +example of the hash table so here's a + + align:start position:0% +example of the hash table so here's a + + + align:start position:0% +example of the hash table so here's a +typical hash table it's got collisions + + align:start position:0% +typical hash table it's got collisions + + + align:start position:0% +typical hash table it's got collisions +resolved by chaining so you have a bunch + + align:start position:0% +resolved by chaining so you have a bunch + + + align:start position:0% +resolved by chaining so you have a bunch +of linked lists you hash to a particular + + align:start position:0% +of linked lists you hash to a particular + + + align:start position:0% +of linked lists you hash to a particular +slot in the table and then you chase + + align:start position:0% +slot in the table and then you chase + + + align:start position:0% +slot in the table and then you chase +down the linked list to find the value + + align:start position:0% +down the linked list to find the value + + + align:start position:0% +down the linked list to find the value +and so for example if I'm going to + + align:start position:0% +and so for example if I'm going to + + + align:start position:0% +and so for example if I'm going to +insert X which has a key value of 81 you + + align:start position:0% +insert X which has a key value of 81 you + + + align:start position:0% +insert X which has a key value of 81 you +know what I do is figure out which slot + + align:start position:0% +know what I do is figure out which slot + + + align:start position:0% +know what I do is figure out which slot +I go to by by hashing the key and then + + align:start position:0% +I go to by by hashing the key and then + + + align:start position:0% +I go to by by hashing the key and then +in this case I made it be the last one + + align:start position:0% +in this case I made it be the last one + + + align:start position:0% +in this case I made it be the last one +so the animations could be easier but if + + align:start position:0% +so the animations could be easier but if + + + align:start position:0% +so the animations could be easier but if +it were in the middle and so so now what + + align:start position:0% +it were in the middle and so so now what + + + align:start position:0% +it were in the middle and so so now what +do I do is I make the the pointer of X + + align:start position:0% +do I do is I make the the pointer of X + + + align:start position:0% +do I do is I make the the pointer of X +go to the you know first element of that + + align:start position:0% +go to the you know first element of that + + + align:start position:0% +go to the you know first element of that +list and then I make the slot value now + + align:start position:0% +list and then I make the slot value now + + + align:start position:0% +list and then I make the slot value now +point to X and that effectively in with + + align:start position:0% +point to X and that effectively in with + + + align:start position:0% +point to X and that effectively in with +a constant number of operations inserts + + align:start position:0% +a constant number of operations inserts + + + align:start position:0% +a constant number of operations inserts +X into the hash table and in particular + + align:start position:0% +X into the hash table and in particular + + + align:start position:0% +X into the hash table and in particular +into the linked list in the slot that + + align:start position:0% +into the linked list in the slot that + + + align:start position:0% +into the linked list in the slot that +it's supposed to be okay this is all + + align:start position:0% +it's supposed to be okay this is all + + + align:start position:0% +it's supposed to be okay this is all +familiar right okay so now what happens + + align:start position:0% +familiar right okay so now what happens + + + align:start position:0% +familiar right okay so now what happens +when you have multiple parallel + + align:start position:0% +when you have multiple parallel + + + align:start position:0% +when you have multiple parallel +instructions that are accessing the same + + align:start position:0% +instructions that are accessing the same + + + align:start position:0% +instructions that are accessing the same +the same locations okay so so here we + + align:start position:0% +the same locations okay so so here we + + + align:start position:0% +the same locations okay so so here we +have two threads one inserting X and one + + align:start position:0% +have two threads one inserting X and one + + + align:start position:0% +have two threads one inserting X and one +inserting Y and X goes it does its thing + + align:start position:0% +inserting Y and X goes it does its thing + + + align:start position:0% +inserting Y and X goes it does its thing +it hashes to there and it then sets the + + align:start position:0% +it hashes to there and it then sets the + + + align:start position:0% +it hashes to there and it then sets the +next pointer to be the to add itself + + align:start position:0% +next pointer to be the to add itself + + + align:start position:0% +next pointer to be the to add itself +into the list and then there's this + + align:start position:0% +into the list and then there's this + + + align:start position:0% +into the list and then there's this +other thing going on in parallel which + + align:start position:0% +other thing going on in parallel which + + + align:start position:0% +other thing going on in parallel which +effectively says oh I'm going to hash + + align:start position:0% +effectively says oh I'm going to hash + + + align:start position:0% +effectively says oh I'm going to hash +oh we're going to the same slot it + + align:start position:0% +oh we're going to the same slot it + + + align:start position:0% +oh we're going to the same slot it +doesn't know that somebody's already + + align:start position:0% +doesn't know that somebody's already + + + align:start position:0% +doesn't know that somebody's already +there and so then it decides it's going + + align:start position:0% +there and so then it decides it's going + + + align:start position:0% +there and so then it decides it's going +to put itself in as the first element + + align:start position:0% +to put itself in as the first element + + + align:start position:0% +to put itself in as the first element +of the list and then it sets the value + + align:start position:0% +of the list and then it sets the value + + + align:start position:0% +of the list and then it sets the value +of y that sets the value of the slot to + + align:start position:0% +of y that sets the value of the slot to + + + align:start position:0% +of y that sets the value of the slot to +point to Y and then along comes X + + align:start position:0% +point to Y and then along comes X + + + align:start position:0% +point to Y and then along comes X +finishing off what it's doing and it + + align:start position:0% +finishing off what it's doing and it + + + align:start position:0% +finishing off what it's doing and it +points the value to X and you can see + + align:start position:0% +points the value to X and you can see + + + align:start position:0% +points the value to X and you can see +that we have a race bug here a really + + align:start position:0% +that we have a race bug here a really + + + align:start position:0% +that we have a race bug here a really +nasty one because we've just destroyed + + align:start position:0% +nasty one because we've just destroyed + + + align:start position:0% +nasty one because we've just destroyed +the integrity of our of our system we + + align:start position:0% +the integrity of our of our system we + + + align:start position:0% +the integrity of our of our system we +now have in particular y is sort of + + align:start position:0% +now have in particular y is sort of + + + align:start position:0% +now have in particular y is sort of +floating not in the list when it's + + align:start position:0% +floating not in the list when it's + + + align:start position:0% +floating not in the list when it's +supposed to be in the list right so the + + align:start position:0% +supposed to be in the list right so the + + + align:start position:0% +supposed to be in the list right so the +standard solution to this is to make + + align:start position:0% +standard solution to this is to make + + + align:start position:0% +standard solution to this is to make +some of these instructions be atomic ok + + align:start position:0% +some of these instructions be atomic ok + + + align:start position:0% +some of these instructions be atomic ok +so and what that means is the rest of + + align:start position:0% +so and what that means is the rest of + + + align:start position:0% +so and what that means is the rest of +the system can never view them as being + + align:start position:0% +the system can never view them as being + + + align:start position:0% +the system can never view them as being +partially executed okay so they're + + align:start position:0% +partially executed okay so they're + + + align:start position:0% +partially executed okay so they're +either all have been executed or none of + + align:start position:0% +either all have been executed or none of + + + align:start position:0% +either all have been executed or none of +them have been executed at any point in + + align:start position:0% +them have been executed at any point in + + + align:start position:0% +them have been executed at any point in +time as far as the as far as the rest of + + align:start position:0% +time as far as the as far as the rest of + + + align:start position:0% +time as far as the as far as the rest of +the system is concerned okay and the + + align:start position:0% +the system is concerned okay and the + + + align:start position:0% +the system is concerned okay and the +part of code that is within the atomic + + align:start position:0% +part of code that is within the atomic + + + align:start position:0% +part of code that is within the atomic +regions called the critical section and + + align:start position:0% +regions called the critical section and + + + align:start position:0% +regions called the critical section and +it can typically a critical section of + + align:start position:0% +it can typically a critical section of + + + align:start position:0% +it can typically a critical section of +code is someplace that should not be + + align:start position:0% +code is someplace that should not be + + + align:start position:0% +code is someplace that should not be +being executed by two things at the same + + align:start position:0% +being executed by two things at the same + + + align:start position:0% +being executed by two things at the same +time so the standard solution to + + align:start position:0% +time so the standard solution to + + + align:start position:0% +time so the standard solution to +atomicity is to use what's called a + + align:start position:0% +atomicity is to use what's called a + + + align:start position:0% +atomicity is to use what's called a +mutex lock or a mutual exclusion lock + + align:start position:0% +mutex lock or a mutual exclusion lock + + + align:start position:0% +mutex lock or a mutual exclusion lock +okay and it's basically an object with a + + align:start position:0% +okay and it's basically an object with a + + + align:start position:0% +okay and it's basically an object with a +lock and unlock member functions and an + + align:start position:0% +lock and unlock member functions and an + + + align:start position:0% +lock and unlock member functions and an +attempt by a thread to lock an already + + align:start position:0% +attempt by a thread to lock an already + + + align:start position:0% +attempt by a thread to lock an already +locked mutex causes the thread to block + + align:start position:0% +locked mutex causes the thread to block + + + align:start position:0% +locked mutex causes the thread to block +okay that is wait until the mutex is + + align:start position:0% +okay that is wait until the mutex is + + + align:start position:0% +okay that is wait until the mutex is +unlocked okay so if somebody grabs the + + align:start position:0% +unlocked okay so if somebody grabs the + + + align:start position:0% +unlocked okay so if somebody grabs the +lock somebody else grabs the lock and + + align:start position:0% +lock somebody else grabs the lock and + + + align:start position:0% +lock somebody else grabs the lock and +it's already taken then they have to + + align:start position:0% +it's already taken then they have to + + + align:start position:0% +it's already taken then they have to +wait and they sit there waiting until + + align:start position:0% +wait and they sit there waiting until + + + align:start position:0% +wait and they sit there waiting until +until this guy says yes I'm gonna + + align:start position:0% +until this guy says yes I'm gonna + + + align:start position:0% +until this guy says yes I'm gonna +release it okay so so what we'll do now + + align:start position:0% +release it okay so so what we'll do now + + + align:start position:0% +release it okay so so what we'll do now +is we'll make each straw each slot be a + + align:start position:0% +is we'll make each straw each slot be a + + + align:start position:0% +is we'll make each straw each slot be a +struct with a mutex l and a pointer head + + align:start position:0% +struct with a mutex l and a pointer head + + + align:start position:0% +struct with a mutex l and a pointer head +to the slot context so it's going to be + + align:start position:0% +to the slot context so it's going to be + + + align:start position:0% +to the slot context so it's going to be +the same data structure we had before + + align:start position:0% +the same data structure we had before + + + align:start position:0% +the same data structure we had before +but now I'm gonna have not just the + + align:start position:0% +but now I'm gonna have not just the + + + align:start position:0% +but now I'm gonna have not just the +pointer from the slot but I'll also have + + align:start position:0% +pointer from the slot but I'll also have + + + align:start position:0% +pointer from the slot but I'll also have +I also have a a lock in that position + + align:start position:0% +I also have a a lock in that position + + + align:start position:0% +I also have a a lock in that position +okay and so the idea of in the code now + + align:start position:0% +okay and so the idea of in the code now + + + align:start position:0% +okay and so the idea of in the code now +is that before I access the lock before + + align:start position:0% +is that before I access the lock before + + + align:start position:0% +is that before I access the lock before +I access the list I'm going to lock that + + align:start position:0% +I access the list I'm going to lock that + + + align:start position:0% +I access the list I'm going to lock that +that list in the table by locking the + + align:start position:0% +that list in the table by locking the + + + align:start position:0% +that list in the table by locking the +slot then I'll do the things that I need + + align:start position:0% +slot then I'll do the things that I need + + + align:start position:0% +slot then I'll do the things that I need +to do and then I'll unlock it and now + + align:start position:0% +to do and then I'll unlock it and now + + + align:start position:0% +to do and then I'll unlock it and now +anything else can go on because you know + + align:start position:0% +anything else can go on because you know + + + align:start position:0% +anything else can go on because you know +the what's happening is the reason we're + + align:start position:0% +the what's happening is the reason we're + + + align:start position:0% +the what's happening is the reason we're +getting into trouble is because we got + + align:start position:0% +getting into trouble is because we got + + + align:start position:0% +getting into trouble is because we got +some sort of interleaving of operations + + align:start position:0% +some sort of interleaving of operations + + + align:start position:0% +some sort of interleaving of operations +and our goal is to make sure that it's + + align:start position:0% +and our goal is to make sure that it's + + + align:start position:0% +and our goal is to make sure that it's +either doing this or doing this and + + align:start position:0% +either doing this or doing this and + + + align:start position:0% +either doing this or doing this and +never this okay to make sure that so + + align:start position:0% +never this okay to make sure that so + + + align:start position:0% +never this okay to make sure that so +that each thing each piece of code is + + align:start position:0% +that each thing each piece of code is + + + align:start position:0% +that each thing each piece of code is +restoring the invariant of correctness + + align:start position:0% +restoring the invariant of correctness + + + align:start position:0% +restoring the invariant of correctness +after it executes the pointer swaps them + + align:start position:0% +after it executes the pointer swaps them + + + align:start position:0% +after it executes the pointer swaps them +very in this case is that the elements + + align:start position:0% +very in this case is that the elements + + + align:start position:0% +very in this case is that the elements +are in a list okay and and so you want + + align:start position:0% +are in a list okay and and so you want + + + align:start position:0% +are in a list okay and and so you want +to restore that with each one okay so so + + align:start position:0% +to restore that with each one okay so so + + + align:start position:0% +to restore that with each one okay so so +mutex is this is one way you can use new + + align:start position:0% +mutex is this is one way you can use new + + + align:start position:0% +mutex is this is one way you can use new +mutexes to implement atomicity okay so + + align:start position:0% +mutexes to implement atomicity okay so + + + align:start position:0% +mutexes to implement atomicity okay so +now let's just go back this is this is + + align:start position:0% +now let's just go back this is this is + + + align:start position:0% +now let's just go back this is this is +so who has who has seen you know mutexes + + align:start position:0% +so who has who has seen you know mutexes + + + align:start position:0% +so who has who has seen you know mutexes +before it's at pretty much everybody + + align:start position:0% +before it's at pretty much everybody + + + align:start position:0% +before it's at pretty much everybody +yeah okay good I hope that this is not + + align:start position:0% +yeah okay good I hope that this is not + + + align:start position:0% +yeah okay good I hope that this is not +brand-new for too many of you if it is + + align:start position:0% +brand-new for too many of you if it is + + + align:start position:0% +brand-new for too many of you if it is +brand-new that's great but what I'm + + align:start position:0% +brand-new that's great but what I'm + + + align:start position:0% +brand-new that's great but what I'm +trying to do is make it so let's go back + + align:start position:0% +trying to do is make it so let's go back + + + align:start position:0% +trying to do is make it so let's go back +a little bit and recall in this class + + align:start position:0% +a little bit and recall in this class + + + align:start position:0% +a little bit and recall in this class +our discussion of determinacy races so + + align:start position:0% +our discussion of determinacy races so + + + align:start position:0% +our discussion of determinacy races so +remember that determinacy race occurs + + align:start position:0% +remember that determinacy race occurs + + + align:start position:0% +remember that determinacy race occurs +when you have to logically parallel + + align:start position:0% +when you have to logically parallel + + + align:start position:0% +when you have to logically parallel +instructions that access the same memory + + align:start position:0% +instructions that access the same memory + + + align:start position:0% +instructions that access the same memory +location and at least one of them + + align:start position:0% +location and at least one of them + + + align:start position:0% +location and at least one of them +performs all right okay so mutex locks + + align:start position:0% +performs all right okay so mutex locks + + + align:start position:0% +performs all right okay so mutex locks +can guarantee that critical sections + + align:start position:0% +can guarantee that critical sections + + + align:start position:0% +can guarantee that critical sections +behave atomically but the resulting code + + align:start position:0% +behave atomically but the resulting code + + + align:start position:0% +behave atomically but the resulting code +is inherently non-deterministic because + + align:start position:0% +is inherently non-deterministic because + + + align:start position:0% +is inherently non-deterministic because +you've got a you know we had a race bug + + align:start position:0% +you've got a you know we had a race bug + + + align:start position:0% +you've got a you know we had a race bug +there right we had two things trying to + + align:start position:0% +there right we had two things trying to + + + align:start position:0% +there right we had two things trying to +access the same slot but that may be + + align:start position:0% +access the same slot but that may be + + + align:start position:0% +access the same slot but that may be +what I + + align:start position:0% +what I + + + align:start position:0% +what I +want right I want to have a shared hash + + align:start position:0% +want right I want to have a shared hash + + + align:start position:0% +want right I want to have a shared hash +table maybe okay for these for these + + align:start position:0% +table maybe okay for these for these + + + align:start position:0% +table maybe okay for these for these +things so I want something where there + + align:start position:0% +things so I want something where there + + + align:start position:0% +things so I want something where there +is a race but I just don't want to have + + align:start position:0% +is a race but I just don't want to have + + + align:start position:0% +is a race but I just don't want to have +the anomalies that arise in this case + + align:start position:0% +the anomalies that arise in this case + + + align:start position:0% +the anomalies that arise in this case +you know the race bug caused things and + + align:start position:0% +you know the race bug caused things and + + + align:start position:0% +you know the race bug caused things and +I can solve that with atomicity okay you + + align:start position:0% +I can solve that with atomicity okay you + + + align:start position:0% +I can solve that with atomicity okay you +know if you have no determinacy races it + + align:start position:0% +know if you have no determinacy races it + + + align:start position:0% +know if you have no determinacy races it +means that the program is deterministic + + align:start position:0% +means that the program is deterministic + + + align:start position:0% +means that the program is deterministic +on that input and that it always behaves + + align:start position:0% +on that input and that it always behaves + + + align:start position:0% +on that input and that it always behaves +the same okay and remember also that if + + align:start position:0% +the same okay and remember also that if + + + align:start position:0% +the same okay and remember also that if +a determinacy race exists in an + + align:start position:0% +a determinacy race exists in an + + + align:start position:0% +a determinacy race exists in an +ostensibly deterministic program okay + + align:start position:0% +ostensibly deterministic program okay + + + align:start position:0% +ostensibly deterministic program okay +then it guarantees to find a race now if + + align:start position:0% +then it guarantees to find a race now if + + + align:start position:0% +then it guarantees to find a race now if +you put in mutexes you still have a + + align:start position:0% +you put in mutexes you still have a + + + align:start position:0% +you put in mutexes you still have a +non-deterministic program you still have + + align:start position:0% +non-deterministic program you still have + + + align:start position:0% +non-deterministic program you still have +a race because you have two things that + + align:start position:0% +a race because you have two things that + + + align:start position:0% +a race because you have two things that +are logically parallel that are both + + align:start position:0% +are logically parallel that are both + + + align:start position:0% +are logically parallel that are both +accessing the lock that's a rate that's + + align:start position:0% +accessing the lock that's a rate that's + + + align:start position:0% +accessing the lock that's a rate that's +a determinacy race okay if you have two + + align:start position:0% +a determinacy race okay if you have two + + + align:start position:0% +a determinacy race okay if you have two +things that are in parallel they're both + + align:start position:0% +things that are in parallel they're both + + + align:start position:0% +things that are in parallel they're both +accessing the lock + + align:start position:0% +accessing the lock + + + align:start position:0% +accessing the lock +that's a determinacy race it may be a + + align:start position:0% +that's a determinacy race it may be a + + + align:start position:0% +that's a determinacy race it may be a +safe correct one but it is a determinacy + + align:start position:0% +safe correct one but it is a determinacy + + + align:start position:0% +safe correct one but it is a determinacy +race okay and so any codes that use + + align:start position:0% +race okay and so any codes that use + + + align:start position:0% +race okay and so any codes that use +locks are non-deterministic by intention + + align:start position:0% +locks are non-deterministic by intention + + + align:start position:0% +locks are non-deterministic by intention +and they're going to invalidate the + + align:start position:0% +and they're going to invalidate the + + + align:start position:0% +and they're going to invalidate the +silks and guarantee of finding those + + align:start position:0% +silks and guarantee of finding those + + + align:start position:0% +silks and guarantee of finding those +race bugs okay so you will end up with + + align:start position:0% +race bugs okay so you will end up with + + + align:start position:0% +race bugs okay so you will end up with +races in your code if you're not careful + + align:start position:0% +races in your code if you're not careful + + + align:start position:0% +races in your code if you're not careful +okay and so this is one reason it's + + align:start position:0% +okay and so this is one reason it's + + + align:start position:0% +okay and so this is one reason it's +important to have some way of turning + + align:start position:0% +important to have some way of turning + + + align:start position:0% +important to have some way of turning +off non determinism to detect stuff + + align:start position:0% +off non determinism to detect stuff + + + align:start position:0% +off non determinism to detect stuff +because what you don't want is that + + align:start position:0% +because what you don't want is that + + + align:start position:0% +because what you don't want is that +whole rash of false positives saying oh + + align:start position:0% +whole rash of false positives saying oh + + + align:start position:0% +whole rash of false positives saying oh +you raced on gathering this lock nor do + + align:start position:0% +you raced on gathering this lock nor do + + + align:start position:0% +you raced on gathering this lock nor do +you want to ignore that and then + + align:start position:0% +you want to ignore that and then + + + align:start position:0% +you want to ignore that and then +discover that a race has popped up + + align:start position:0% +discover that a race has popped up + + + align:start position:0% +discover that a race has popped up +somewhere else okay now some people feel + + align:start position:0% +somewhere else okay now some people feel + + + align:start position:0% +somewhere else okay now some people feel +that so this is basically a talking + + align:start position:0% +that so this is basically a talking + + + align:start position:0% +that so this is basically a talking +about having a data race okay and a data + + align:start position:0% +about having a data race okay and a data + + + align:start position:0% +about having a data race okay and a data +race is similar to the definition of + + align:start position:0% +race is similar to the definition of + + + align:start position:0% +race is similar to the definition of +determinacy race okay but it says that + + align:start position:0% +determinacy race okay but it says that + + + align:start position:0% +determinacy race okay but it says that +you have to logically parallel + + align:start position:0% +you have to logically parallel + + + align:start position:0% +you have to logically parallel +instructions and they don't hold locks + + align:start position:0% +instructions and they don't hold locks + + + align:start position:0% +instructions and they don't hold locks +in common + + align:start position:0% +in common + + + align:start position:0% +in common +and then it's the same definition if + + align:start position:0% +and then it's the same definition if + + + align:start position:0% +and then it's the same definition if +they access the same memory location one + + align:start position:0% +they access the same memory location one + + + align:start position:0% +they access the same memory location one +of them performs or right then you have + + align:start position:0% +of them performs or right then you have + + + align:start position:0% +of them performs or right then you have +a then you have a data race bug okay but + + align:start position:0% +a then you have a data race bug okay but + + + align:start position:0% +a then you have a data race bug okay but +if they if they have the locks in common + + align:start position:0% +if they if they have the locks in common + + + align:start position:0% +if they if they have the locks in common +okay if they both have acquired at least + + align:start position:0% +okay if they both have acquired at least + + + align:start position:0% +okay if they both have acquired at least +one lock that's the same then you don't + + align:start position:0% +one lock that's the same then you don't + + + align:start position:0% +one lock that's the same then you don't +have a data race okay because that means + + align:start position:0% +have a data race okay because that means + + + align:start position:0% +have a data race okay because that means +that you've now successfully protected + + align:start position:0% +that you've now successfully protected + + + align:start position:0% +that you've now successfully protected +the atomicity but it is still + + align:start position:0% +the atomicity but it is still + + + align:start position:0% +the atomicity but it is still +non-deterministic and there is a + + align:start position:0% +non-deterministic and there is a + + + align:start position:0% +non-deterministic and there is a +determinacy race just no data race and + + align:start position:0% +determinacy race just no data race and + + + align:start position:0% +determinacy race just no data race and +that's the big distinction between data + + align:start position:0% +that's the big distinction between data + + + align:start position:0% +that's the big distinction between data +races and determinacy races and on quiz + + align:start position:0% +races and determinacy races and on quiz + + + align:start position:0% +races and determinacy races and on quiz +2 you better know the difference between + + align:start position:0% +2 you better know the difference between + + + align:start position:0% +2 you better know the difference between +data races and determinacy races okay + + align:start position:0% +data races and determinacy races okay + + + align:start position:0% +data races and determinacy races okay +because they are different okay so a + + align:start position:0% +because they are different okay so a + + + align:start position:0% +because they are different okay so a +program may have no determinant may have + + align:start position:0% +program may have no determinant may have + + + align:start position:0% +program may have no determinant may have +no data races that doesn't mean that it + + align:start position:0% +no data races that doesn't mean that it + + + align:start position:0% +no data races that doesn't mean that it +doesn't have a determinacy race in fact + + align:start position:0% +doesn't have a determinacy race in fact + + + align:start position:0% +doesn't have a determinacy race in fact +if it's got any locks it probably has a + + align:start position:0% +if it's got any locks it probably has a + + + align:start position:0% +if it's got any locks it probably has a +determinacy race okay okay so so one of + + align:start position:0% +determinacy race okay okay so so one of + + + align:start position:0% +determinacy race okay okay so so one of +the things is if I have no data races + + align:start position:0% +the things is if I have no data races + + + align:start position:0% +the things is if I have no data races +does that mean I have no bugs suppose I + + align:start position:0% +does that mean I have no bugs suppose I + + + align:start position:0% +does that mean I have no bugs suppose I +have no data races in my code does that + + align:start position:0% +have no data races in my code does that + + + align:start position:0% +have no data races in my code does that +mean I have no bugs this is quite an + + align:start position:0% +mean I have no bugs this is quite an + + + align:start position:0% +mean I have no bugs this is quite an +obvious answer just bye-bye quiz + + align:start position:0% +obvious answer just bye-bye quiz + + + align:start position:0% +obvious answer just bye-bye quiz +moonship right so what might happen + + align:start position:0% + + + + align:start position:0% + +think about a little bit what might + + align:start position:0% +think about a little bit what might + + + align:start position:0% +think about a little bit what might +happen how could I have no data races + + align:start position:0% +happen how could I have no data races + + + align:start position:0% +happen how could I have no data races +and yet there's still be a bug even + + align:start position:0% +and yet there's still be a bug even + + + align:start position:0% +and yet there's still be a bug even +though and assuming it's a correct piece + + align:start position:0% +though and assuming it's a correct piece + + + align:start position:0% +though and assuming it's a correct piece +of code otherwise okay in other words + + align:start position:0% +of code otherwise okay in other words + + + align:start position:0% +of code otherwise okay in other words +when it runs serially or whatever it's + + align:start position:0% +when it runs serially or whatever it's + + + align:start position:0% +when it runs serially or whatever it's +correct how could I end up having code + + align:start position:0% +correct how could I end up having code + + + align:start position:0% +correct how could I end up having code +no data races but still have a bug + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +yeah but that doesn't mean it's bad + + align:start position:0% +yeah but that doesn't mean it's bad + + + align:start position:0% +yeah but that doesn't mean it's bad +right yep + + align:start position:0% + + + + align:start position:0% + +might still be a different yep + + align:start position:0% + + + + align:start position:0% + +okay uh yeah let me give you an example + + align:start position:0% +okay uh yeah let me give you an example + + + align:start position:0% +okay uh yeah let me give you an example +okay + + align:start position:0% +okay + + + align:start position:0% +okay +which is more to the point here is a way + + align:start position:0% +which is more to the point here is a way + + + align:start position:0% +which is more to the point here is a way +of making sure that I have no data race + + align:start position:0% +of making sure that I have no data race + + + align:start position:0% +of making sure that I have no data race +which is I lock before I follow the + + align:start position:0% +which is I lock before I follow the + + + align:start position:0% +which is I lock before I follow the +table slot value and then I unlock then + + align:start position:0% +table slot value and then I unlock then + + + align:start position:0% +table slot value and then I unlock then +I lock again and then I set the value + + align:start position:0% +I lock again and then I set the value + + + align:start position:0% +I lock again and then I set the value +okay so I haven't prevented the + + align:start position:0% +okay so I haven't prevented the + + + align:start position:0% +okay so I haven't prevented the +atomicity right now I've got an atom + + align:start position:0% +atomicity right now I've got an atom + + + align:start position:0% +atomicity right now I've got an atom +isset II violation but I have no data + + align:start position:0% +isset II violation but I have no data + + + align:start position:0% +isset II violation but I have no data +races okay because I never have two + + align:start position:0% +races okay because I never have two + + + align:start position:0% +races okay because I never have two +things that are going to access things + + align:start position:0% +things that are going to access things + + + align:start position:0% +things that are going to access things +at the same time is protected by the + + align:start position:0% +at the same time is protected by the + + + align:start position:0% +at the same time is protected by the +lock okay but it doesn't solve my + + align:start position:0% +lock okay but it doesn't solve my + + + align:start position:0% +lock okay but it doesn't solve my +atomicity so there's a you know there's + + align:start position:0% +atomicity so there's a you know there's + + + align:start position:0% +atomicity so there's a you know there's +you know you can definitely have no data + + align:start position:0% +you know you can definitely have no data + + + align:start position:0% +you know you can definitely have no data +races but that doesn't mean you have no + + align:start position:0% +races but that doesn't mean you have no + + + align:start position:0% +races but that doesn't mean you have no +bugs okay but usually what it happens is + + align:start position:0% +bugs okay but usually what it happens is + + + align:start position:0% +bugs okay but usually what it happens is +if you have no data races then usually + + align:start position:0% +if you have no data races then usually + + + align:start position:0% +if you have no data races then usually +the programmer actually got this code + + align:start position:0% +the programmer actually got this code + + + align:start position:0% +the programmer actually got this code +right okay it's one of these things + + align:start position:0% +right okay it's one of these things + + + align:start position:0% +right okay it's one of these things +we're demonstrating no data races is in + + align:start position:0% +we're demonstrating no data races is in + + + align:start position:0% +we're demonstrating no data races is in +fact you know a very positive thing in + + align:start position:0% +fact you know a very positive thing in + + + align:start position:0% +fact you know a very positive thing in +your code it doesn't mean the program I + + align:start position:0% +your code it doesn't mean the program I + + + align:start position:0% +your code it doesn't mean the program I +did right but most of the time the + + align:start position:0% +did right but most of the time the + + + align:start position:0% +did right but most of the time the +reason they're putting in the in the + + align:start position:0% +reason they're putting in the in the + + + align:start position:0% +reason they're putting in the in the +locks is to provide atomicity for + + align:start position:0% +locks is to provide atomicity for + + + align:start position:0% +locks is to provide atomicity for +something and they usually get it right + + align:start position:0% +something and they usually get it right + + + align:start position:0% +something and they usually get it right +they don't always get it right in fact + + align:start position:0% +they don't always get it right in fact + + + align:start position:0% +they don't always get it right in fact +Java for example had a very famous bug + + align:start position:0% +Java for example had a very famous bug + + + align:start position:0% +Java for example had a very famous bug +early on in the way that it specified + + align:start position:0% + + + + align:start position:0% + +locking such that you know the you could + + align:start position:0% +locking such that you know the you could + + + align:start position:0% +locking such that you know the you could +look at the length of a string and then + + align:start position:0% +look at the length of a string and then + + + align:start position:0% +look at the length of a string and then +modify it and then you would end up with + + align:start position:0% +modify it and then you would end up with + + + align:start position:0% +modify it and then you would end up with +a race bug because somebody else could + + align:start position:0% +a race bug because somebody else could + + + align:start position:0% +a race bug because somebody else could +swoop in in between so they thought they + + align:start position:0% +swoop in in between so they thought they + + + align:start position:0% +swoop in in between so they thought they +were being providing atomicity and they + + align:start position:0% +were being providing atomicity and they + + + align:start position:0% +were being providing atomicity and they +didn't okay + + align:start position:0% +didn't okay + + + align:start position:0% +didn't okay +so there's there's another set of issues + + align:start position:0% +so there's there's another set of issues + + + align:start position:0% +so there's there's another set of issues +here having to do with benign races now + + align:start position:0% +here having to do with benign races now + + + align:start position:0% +here having to do with benign races now +there's some people who argue that no + + align:start position:0% +there's some people who argue that no + + + align:start position:0% +there's some people who argue that no +races are + + align:start position:0% +races are + + + align:start position:0% +races are +are no determinacy races are benign and + + align:start position:0% + + + + align:start position:0% + +they make academic statements that I + + align:start position:0% +they make academic statements that I + + + align:start position:0% +they make academic statements that I +find quite compelling actually what + + align:start position:0% +find quite compelling actually what + + + align:start position:0% +find quite compelling actually what +they're what they say about about races + + align:start position:0% +they're what they say about about races + + + align:start position:0% +they're what they say about about races +and whether races are benign but + + align:start position:0% +and whether races are benign but + + + align:start position:0% +and whether races are benign but +nevertheless the literature also + + align:start position:0% +nevertheless the literature also + + + align:start position:0% +nevertheless the literature also +continues to use the term benign race + + align:start position:0% +continues to use the term benign race + + + align:start position:0% +continues to use the term benign race +for this kind of example so suppose we + + align:start position:0% +for this kind of example so suppose we + + + align:start position:0% +for this kind of example so suppose we +want to identify what are is the set of + + align:start position:0% +want to identify what are is the set of + + + align:start position:0% +want to identify what are is the set of +digits that perform that occurred in + + align:start position:0% +digits that perform that occurred in + + + align:start position:0% +digits that perform that occurred in +this in in some array so here's an array + + align:start position:0% +this in in some array so here's an array + + + align:start position:0% +this in in some array so here's an array +with a bunch of values in it okay each + + align:start position:0% +with a bunch of values in it okay each + + + align:start position:0% +with a bunch of values in it okay each +one being a digit from zero to nine so I + + align:start position:0% +one being a digit from zero to nine so I + + + align:start position:0% +one being a digit from zero to nine so I +could write a little piece of code that + + align:start position:0% +could write a little piece of code that + + + align:start position:0% +could write a little piece of code that +runs through my digits array of length + + align:start position:0% +runs through my digits array of length + + + align:start position:0% +runs through my digits array of length +10 and sets the number of digits I've + + align:start position:0% +10 and sets the number of digits I've + + + align:start position:0% +10 and sets the number of digits I've +seen so far of each value to be 0 okay + + align:start position:0% +seen so far of each value to be 0 okay + + + align:start position:0% +seen so far of each value to be 0 okay +and now I go through and I'm gonna do + + align:start position:0% +and now I go through and I'm gonna do + + + align:start position:0% +and now I go through and I'm gonna do +this in parallel and I'm going to set + + align:start position:0% +this in parallel and I'm going to set + + + align:start position:0% +this in parallel and I'm going to set +every time I see a value a of I suppose + + align:start position:0% +every time I see a value a of I suppose + + + align:start position:0% +every time I see a value a of I suppose +a of I is 3 I set the location of a 3 to + + align:start position:0% +a of I is 3 I set the location of a 3 to + + + align:start position:0% +a of I is 3 I set the location of a 3 to +be 1 and otherwise and now otherwise + + align:start position:0% +be 1 and otherwise and now otherwise + + + align:start position:0% +be 1 and otherwise and now otherwise +it's zero because that's what I had it + + align:start position:0% +it's zero because that's what I had it + + + align:start position:0% +it's zero because that's what I had it +before so here's the kind of thing I + + align:start position:0% +before so here's the kind of thing I + + + align:start position:0% +before so here's the kind of thing I +have so for example I can have both of + + align:start position:0% +have so for example I can have both of + + + align:start position:0% +have so for example I can have both of +those sixes are in parallel going to + + align:start position:0% +those sixes are in parallel going to + + + align:start position:0% +those sixes are in parallel going to +access the location 6 to set it to 1 but + + align:start position:0% +access the location 6 to set it to 1 but + + + align:start position:0% +access the location 6 to set it to 1 but +they're both setting it to 1 it doesn't + + align:start position:0% +they're both setting it to 1 it doesn't + + + align:start position:0% +they're both setting it to 1 it doesn't +really matter what order they do it in + + align:start position:0% +really matter what order they do it in + + + align:start position:0% +really matter what order they do it in +you're gonna get the same value there 1 + + align:start position:0% +you're gonna get the same value there 1 + + + align:start position:0% +you're gonna get the same value there 1 +ok and so there's a race maybe we don't + + align:start position:0% +ok and so there's a race maybe we don't + + + align:start position:0% +ok and so there's a race maybe we don't +too much care about that race okay + + align:start position:0% +too much care about that race okay + + + align:start position:0% +too much care about that race okay +because they're both setting the same + + align:start position:0% +because they're both setting the same + + + align:start position:0% +because they're both setting the same +value we're not going to get an + + align:start position:0% +value we're not going to get an + + + align:start position:0% +value we're not going to get an +incorrect value well not exactly + + align:start position:0% +incorrect value well not exactly + + + align:start position:0% +incorrect value well not exactly +we might get on some architecture on the + + align:start position:0% +we might get on some architecture on the + + + align:start position:0% +we might get on some architecture on the +Intel architectures you won't get an + + align:start position:0% +Intel architectures you won't get an + + + align:start position:0% +Intel architectures you won't get an +incorrect value on x86 but there are + + align:start position:0% +incorrect value on x86 but there are + + + align:start position:0% +incorrect value on x86 but there are +codes where the elements of the array + + align:start position:0% +codes where the elements of the array + + + align:start position:0% +codes where the elements of the array +values are not set atomically so for + + align:start position:0% +values are not set atomically so for + + + align:start position:0% +values are not set atomically so for +example on the mips architecture + + align:start position:0% +example on the mips architecture + + + align:start position:0% +example on the mips architecture +in order to set a bite to be a + + align:start position:0% +in order to set a bite to be a + + + align:start position:0% +in order to set a bite to be a +particular value you have to you have to + + align:start position:0% +particular value you have to you have to + + + align:start position:0% +particular value you have to you have to +fetch the word mask out set the word and + + align:start position:0% +fetch the word mask out set the word and + + + align:start position:0% +fetch the word mask out set the word and +then store it back in set the the bite + + align:start position:0% +then store it back in set the the bite + + + align:start position:0% +then store it back in set the the bite +and then store it back into the word and + + align:start position:0% +and then store it back into the word and + + + align:start position:0% +and then store it back into the word and +so if there are two guys who are + + align:start position:0% +so if there are two guys who are + + + align:start position:0% +so if there are two guys who are +basically operating on that same word + + align:start position:0% +basically operating on that same word + + + align:start position:0% +basically operating on that same word +location they will have a race even + + align:start position:0% +location they will have a race even + + + align:start position:0% +location they will have a race even +though in the code it looks like they're + + align:start position:0% +though in the code it looks like they're + + + align:start position:0% +though in the code it looks like they're +just setting bites does that make sense + + align:start position:0% +just setting bites does that make sense + + + align:start position:0% +just setting bites does that make sense +okay so nasty nasty bugs okay that's + + align:start position:0% +okay so nasty nasty bugs okay that's + + + align:start position:0% +okay so nasty nasty bugs okay that's +that's why you should never do + + align:start position:0% +that's why you should never do + + + align:start position:0% +that's why you should never do +non-deterministic programming okay + + align:start position:0% +non-deterministic programming okay + + + align:start position:0% +non-deterministic programming okay +unless you have to + + align:start position:0% +unless you have to + + + align:start position:0% +unless you have to +okay so silks and allows you to turn off + + align:start position:0% +okay so silks and allows you to turn off + + + align:start position:0% +okay so silks and allows you to turn off +race detection for intentional races + + align:start position:0% +race detection for intentional races + + + align:start position:0% +race detection for intentional races +okay so if you really meant there to be + + align:start position:0% +okay so if you really meant there to be + + + align:start position:0% +okay so if you really meant there to be +a race as in this case you can turn it + + align:start position:0% +a race as in this case you can turn it + + + align:start position:0% +a race as in this case you can turn it +off + + align:start position:0% +off + + + align:start position:0% +off +this is dangerous but practical turns + + align:start position:0% +this is dangerous but practical turns + + + align:start position:0% +this is dangerous but practical turns +out usually you're not turning it off + + align:start position:0% +out usually you're not turning it off + + + align:start position:0% +out usually you're not turning it off +for because here's what can happen you + + align:start position:0% +for because here's what can happen you + + + align:start position:0% +for because here's what can happen you +can turn it off and yet then there's + + align:start position:0% +can turn it off and yet then there's + + + align:start position:0% +can turn it off and yet then there's +something else which is using that same + + align:start position:0% +something else which is using that same + + + align:start position:0% +something else which is using that same +stuff and now you're running silks and + + align:start position:0% +stuff and now you're running silks and + + + align:start position:0% +stuff and now you're running silks and +without you know having turned it off + + align:start position:0% +without you know having turned it off + + + align:start position:0% +without you know having turned it off +for exactly what your race might be + + align:start position:0% +for exactly what your race might be + + + align:start position:0% +for exactly what your race might be +they're better solutions so in Intel's + + align:start position:0% +they're better solutions so in Intel's + + + align:start position:0% +they're better solutions so in Intel's +silk screen there's the notion of fake + + align:start position:0% +silk screen there's the notion of fake + + + align:start position:0% +silk screen there's the notion of fake +locks we just have not yet implemented + + align:start position:0% +locks we just have not yet implemented + + + align:start position:0% +locks we just have not yet implemented +it in in the open silk compiler so we + + align:start position:0% +it in in the open silk compiler so we + + + align:start position:0% +it in in the open silk compiler so we +will and in silks and we'll eventually + + align:start position:0% +will and in silks and we'll eventually + + + align:start position:0% +will and in silks and we'll eventually +get to doing that and then people who + + align:start position:0% +get to doing that and then people who + + + align:start position:0% +get to doing that and then people who +take this class in the future will have + + align:start position:0% +take this class in the future will have + + + align:start position:0% +take this class in the future will have +an easier time with that okay because + + align:start position:0% +an easier time with that okay because + + + align:start position:0% +an easier time with that okay because +we'll be able to check for that as well + + align:start position:0% +we'll be able to check for that as well + + + align:start position:0% +we'll be able to check for that as well +okay so any questions about these + + align:start position:0% +okay so any questions about these + + + align:start position:0% +okay so any questions about these +notions so you can see the notions of + + align:start position:0% +notions so you can see the notions of + + + align:start position:0% +notions so you can see the notions of +races can get quite hairy and you know + + align:start position:0% +races can get quite hairy and you know + + + align:start position:0% +races can get quite hairy and you know +make it quite difficult to do your + + align:start position:0% +make it quite difficult to do your + + + align:start position:0% +make it quite difficult to do your +debugging and in fact even can confound + + align:start position:0% +debugging and in fact even can confound + + + align:start position:0% +debugging and in fact even can confound +your tools that are supposed to be + + align:start position:0% +your tools that are supposed to be + + + align:start position:0% +your tools that are supposed to be +helping you to get correct code okay + + align:start position:0% +helping you to get correct code okay + + + align:start position:0% +helping you to get correct code okay +all a name of performance okay but we + + align:start position:0% +all a name of performance okay but we + + + align:start position:0% +all a name of performance okay but we +like performance okay any questions + + align:start position:0% +like performance okay any questions + + + align:start position:0% +like performance okay any questions +yeah + + align:start position:0% + + + + align:start position:0% + +yeah so how can some architectures cause + + align:start position:0% +yeah so how can some architectures cause + + + align:start position:0% +yeah so how can some architectures cause +some error so here's the thing is that + + align:start position:0% +some error so here's the thing is that + + + align:start position:0% +some error so here's the thing is that +if I have a let's say a byte array it + + align:start position:0% +if I have a let's say a byte array it + + + align:start position:0% +if I have a let's say a byte array it +may be that this is stored int as as a + + align:start position:0% +may be that this is stored int as as a + + + align:start position:0% +may be that this is stored int as as a +set of let's say 4 byte words okay and + + align:start position:0% +set of let's say 4 byte words okay and + + + align:start position:0% +set of let's say 4 byte words okay and +so although you may write that a of 0 + + align:start position:0% +so although you may write that a of 0 + + + align:start position:0% +so although you may write that a of 0 +gets 1 what it does is it says let me + + align:start position:0% +gets 1 what it does is it says let me + + + align:start position:0% +gets 1 what it does is it says let me +fetch these 4 values because there is no + + align:start position:0% +fetch these 4 values because there is no + + + align:start position:0% +fetch these 4 values because there is no +byte set instruction on some + + align:start position:0% +byte set instruction on some + + + align:start position:0% +byte set instruction on some +architectures it can only set in this + + align:start position:0% +architectures it can only set in this + + + align:start position:0% +architectures it can only set in this +case 32-bit words so it fetches the + + align:start position:0% +case 32-bit words so it fetches the + + + align:start position:0% +case 32-bit words so it fetches the +values it then you know into a register + + align:start position:0% +values it then you know into a register + + + align:start position:0% +values it then you know into a register +it then sets the value in the register + + align:start position:0% +it then sets the value in the register + + + align:start position:0% +it then sets the value in the register +ok by masking so it doesn't set the + + align:start position:0% +ok by masking so it doesn't set the + + + align:start position:0% +ok by masking so it doesn't set the +other things here and then it stores it + + align:start position:0% +other things here and then it stores it + + + align:start position:0% +other things here and then it stores it +back right so that it has a 1 here but + + align:start position:0% +back right so that it has a 1 here but + + + align:start position:0% +back right so that it has a 1 here but +what if somebody at the same time is + + align:start position:0% +what if somebody at the same time is + + + align:start position:0% +what if somebody at the same time is +storing into this location they will + + align:start position:0% +storing into this location they will + + + align:start position:0% +storing into this location they will +fetch it into their own register set + + align:start position:0% +fetch it into their own register set + + + align:start position:0% +fetch it into their own register set +their byte mascot etc and now my right + + align:start position:0% +their byte mascot etc and now my right + + + align:start position:0% +their byte mascot etc and now my right +back is going to we're gonna have a lost + + align:start position:0% +back is going to we're gonna have a lost + + + align:start position:0% +back is going to we're gonna have a lost +update in the in the right backs does + + align:start position:0% +update in the in the right backs does + + + align:start position:0% +update in the in the right backs does +that make sense ok good + + align:start position:0% +that make sense ok good + + + align:start position:0% +that make sense ok good +very good question ya know I went + + align:start position:0% +very good question ya know I went + + + align:start position:0% +very good question ya know I went +through that orally a little bit quicker + + align:start position:0% +through that orally a little bit quicker + + + align:start position:0% +through that orally a little bit quicker +than maybe I should have ok great + + align:start position:0% +than maybe I should have ok great + + + align:start position:0% +than maybe I should have ok great +so let's talk a little bit about + + align:start position:0% +so let's talk a little bit about + + + align:start position:0% +so let's talk a little bit about +implementation I always like to take + + align:start position:0% +implementation I always like to take + + + align:start position:0% +implementation I always like to take +things down one level below what you + + align:start position:0% +things down one level below what you + + + align:start position:0% +things down one level below what you +necessarily need to know in order to do + + align:start position:0% +necessarily need to know in order to do + + + align:start position:0% +necessarily need to know in order to do +things but it's helpful to sort of see + + align:start position:0% +things but it's helpful to sort of see + + + align:start position:0% +things but it's helpful to sort of see +how these things are implemented and + + align:start position:0% +how these things are implemented and + + + align:start position:0% +how these things are implemented and +because then that gives you a better + + align:start position:0% +because then that gives you a better + + + align:start position:0% +because then that gives you a better +sense at a higher level what the what + + align:start position:0% +sense at a higher level what the what + + + align:start position:0% +sense at a higher level what the what +your capabilities are and how things are + + align:start position:0% +your capabilities are and how things are + + + align:start position:0% +your capabilities are and how things are +actually working underneath so let's + + align:start position:0% +actually working underneath so let's + + + align:start position:0% +actually working underneath so let's +talk about how in the mutex is so here + + align:start position:0% +talk about how in the mutex is so here + + + align:start position:0% +talk about how in the mutex is so here +first of all to understand there are + + align:start position:0% +first of all to understand there are + + + align:start position:0% +first of all to understand there are +lots of different mutexes if you look at + + align:start position:0% +lots of different mutexes if you look at + + + align:start position:0% +lots of different mutexes if you look at +an operating system they may have a half + + align:start position:0% +an operating system they may have a half + + + align:start position:0% +an operating system they may have a half +a dozen or more different + + align:start position:0% +a dozen or more different + + + align:start position:0% +a dozen or more different +you Texas different locks that can + + align:start position:0% +you Texas different locks that can + + + align:start position:0% +you Texas different locks that can +provide mutual exclusion or parameters + + align:start position:0% +provide mutual exclusion or parameters + + + align:start position:0% +provide mutual exclusion or parameters +that can be set for what kind of mute + + align:start position:0% +that can be set for what kind of mute + + + align:start position:0% +that can be set for what kind of mute +exes so the first basic difference in + + align:start position:0% +exes so the first basic difference in + + + align:start position:0% +exes so the first basic difference in +most things is whether the mutex is + + align:start position:0% +most things is whether the mutex is + + + align:start position:0% +most things is whether the mutex is +yielding or spinning so a yielding mutex + + align:start position:0% +yielding or spinning so a yielding mutex + + + align:start position:0% +yielding or spinning so a yielding mutex +returns control to the operating system + + align:start position:0% +returns control to the operating system + + + align:start position:0% +returns control to the operating system +when it blocks when a program tries to + + align:start position:0% +when it blocks when a program tries to + + + align:start position:0% +when it blocks when a program tries to +get active when it tries to get access + + align:start position:0% +get active when it tries to get access + + + align:start position:0% +get active when it tries to get access +when a thread tries to get access to a + + align:start position:0% +when a thread tries to get access to a + + + align:start position:0% +when a thread tries to get access to a +given low given lock if it is blocked it + + align:start position:0% +given low given lock if it is blocked it + + + align:start position:0% +given low given lock if it is blocked it +doesn't just sit there and keep and + + align:start position:0% +doesn't just sit there and keep and + + + align:start position:0% +doesn't just sit there and keep and +spinning where you're basically spinning + + align:start position:0% +spinning where you're basically spinning + + + align:start position:0% +spinning where you're basically spinning +means I just sit there checking it and + + align:start position:0% +means I just sit there checking it and + + + align:start position:0% +means I just sit there checking it and +checking it and checking it and checking + + align:start position:0% +checking it and checking it and checking + + + align:start position:0% +checking it and checking it and checking +in ok instead what it does is it says oh + + align:start position:0% +in ok instead what it does is it says oh + + + align:start position:0% +in ok instead what it does is it says oh +I'm doing useless work here let me go + + align:start position:0% +I'm doing useless work here let me go + + + align:start position:0% +I'm doing useless work here let me go +and return control of the operating + + align:start position:0% +and return control of the operating + + + align:start position:0% +and return control of the operating +system maybe there's another thread that + + align:start position:0% +system maybe there's another thread that + + + align:start position:0% +system maybe there's another thread that +can run at the same time and therefore + + align:start position:0% +can run at the same time and therefore + + + align:start position:0% +can run at the same time and therefore +I'll give by switching myself out by + + align:start position:0% +I'll give by switching myself out by + + + align:start position:0% +I'll give by switching myself out by +yielding my my scheduling quantum I will + + align:start position:0% +yielding my my scheduling quantum I will + + + align:start position:0% +yielding my my scheduling quantum I will +get better efficiency overall because + + align:start position:0% +get better efficiency overall because + + + align:start position:0% +get better efficiency overall because +somebody some other thread that is + + align:start position:0% +somebody some other thread that is + + + align:start position:0% +somebody some other thread that is +capable of running can run at that point + + align:start position:0% +capable of running can run at that point + + + align:start position:0% +capable of running can run at that point +ok so is that clear the distinction + + align:start position:0% +ok so is that clear the distinction + + + align:start position:0% +ok so is that clear the distinction +between spinning and and yielding ok + + align:start position:0% +between spinning and and yielding ok + + + align:start position:0% +between spinning and and yielding ok +another one is whether the mutex is + + align:start position:0% +another one is whether the mutex is + + + align:start position:0% +another one is whether the mutex is +reentrant or non re-entrant a reentrant + + align:start position:0% +reentrant or non re-entrant a reentrant + + + align:start position:0% +reentrant or non re-entrant a reentrant +mutex allows a thread that is already + + align:start position:0% +mutex allows a thread that is already + + + align:start position:0% +mutex allows a thread that is already +holding a lock to acquire it again ok a + + align:start position:0% +holding a lock to acquire it again ok a + + + align:start position:0% +holding a lock to acquire it again ok a +non reentrant one deadlocks if the + + align:start position:0% +non reentrant one deadlocks if the + + + align:start position:0% +non reentrant one deadlocks if the +thread attempts to require a mutex that + + align:start position:0% +thread attempts to require a mutex that + + + align:start position:0% +thread attempts to require a mutex that +already holds ok so I grab a lock and + + align:start position:0% +already holds ok so I grab a lock and + + + align:start position:0% +already holds ok so I grab a lock and +now I go to a piece of code and it says + + align:start position:0% +now I go to a piece of code and it says + + + align:start position:0% +now I go to a piece of code and it says +grab that lock so very simple I can + + align:start position:0% +grab that lock so very simple I can + + + align:start position:0% +grab that lock so very simple I can +check to see whether I have if I want to + + align:start position:0% +check to see whether I have if I want to + + + align:start position:0% +check to see whether I have if I want to +be reentrant I can check do I have that + + align:start position:0% +be reentrant I can check do I have that + + + align:start position:0% +be reentrant I can check do I have that +lock already and if I do then I don't + + align:start position:0% +lock already and if I do then I don't + + + align:start position:0% +lock already and if I do then I don't +actually have to acquire it I just keep + + align:start position:0% +actually have to acquire it I just keep + + + align:start position:0% +actually have to acquire it I just keep +going + + align:start position:0% +going + + + align:start position:0% +going +but that's extra overhead it's faster + + align:start position:0% +but that's extra overhead it's faster + + + align:start position:0% +but that's extra overhead it's faster +for me to have a non reentrant lock ok + + align:start position:0% +for me to have a non reentrant lock ok + + + align:start position:0% +for me to have a non reentrant lock ok +where I just simply grab the lock and if + + align:start position:0% +where I just simply grab the lock and if + + + align:start position:0% +where I just simply grab the lock and if +somebody's got it + + align:start position:0% +somebody's got it + + + align:start position:0% +somebody's got it +including me then it's a dead lock but + + align:start position:0% +including me then it's a dead lock but + + + align:start position:0% +including me then it's a dead lock but +now if there's the possibility that I + + align:start position:0% +now if there's the possibility that I + + + align:start position:0% +now if there's the possibility that I +could react wire a lock then that might + + align:start position:0% +could react wire a lock then that might + + + align:start position:0% +could react wire a lock then that might +not be safe + + align:start position:0% +not be safe + + + align:start position:0% +not be safe +okay you have to worry about the + + align:start position:0% +okay you have to worry about the + + + align:start position:0% +okay you have to worry about the +programmer has to worry about that now + + align:start position:0% +programmer has to worry about that now + + + align:start position:0% +programmer has to worry about that now +is that clear that one okay + + align:start position:0% +is that clear that one okay + + + align:start position:0% +is that clear that one okay +and then final basic property of mutexes + + align:start position:0% +and then final basic property of mutexes + + + align:start position:0% +and then final basic property of mutexes +is whether they're fair or unfair okay + + align:start position:0% +is whether they're fair or unfair okay + + + align:start position:0% +is whether they're fair or unfair okay +so here's the thing with it's easiest to + + align:start position:0% +so here's the thing with it's easiest to + + + align:start position:0% +so here's the thing with it's easiest to +think about it in the context of + + align:start position:0% +think about it in the context of + + + align:start position:0% +think about it in the context of +spinning + + align:start position:0% +spinning + + + align:start position:0% +spinning +I have several threads that basically + + align:start position:0% +I have several threads that basically + + + align:start position:0% +I have several threads that basically +came to the same lock and we decide + + align:start position:0% +came to the same lock and we decide + + + align:start position:0% +came to the same lock and we decide +they're gonna spin they're just going to + + align:start position:0% +they're gonna spin they're just going to + + + align:start position:0% +they're gonna spin they're just going to +sit there continually checking waiting + + align:start position:0% +sit there continually checking waiting + + + align:start position:0% +sit there continually checking waiting +for that lock to be free okay so when + + align:start position:0% +for that lock to be free okay so when + + + align:start position:0% +for that lock to be free okay so when +finally the guy who has it unlocks it + + align:start position:0% +finally the guy who has it unlocks it + + + align:start position:0% +finally the guy who has it unlocks it +you know maybe I've got half a dozen + + align:start position:0% +you know maybe I've got half a dozen + + + align:start position:0% +you know maybe I've got half a dozen +threads sitting there one of them wins + + align:start position:0% +threads sitting there one of them wins + + + align:start position:0% +threads sitting there one of them wins +okay and which one wins well if they're + + align:start position:0% +okay and which one wins well if they're + + + align:start position:0% +okay and which one wins well if they're +spinning it could be any one of them + + align:start position:0% +spinning it could be any one of them + + + align:start position:0% +spinning it could be any one of them +then it has one and so the issue that + + align:start position:0% +then it has one and so the issue that + + + align:start position:0% +then it has one and so the issue that +can go on is you could have what's + + align:start position:0% +can go on is you could have what's + + + align:start position:0% +can go on is you could have what's +called a starvation problem okay where + + align:start position:0% +called a starvation problem okay where + + + align:start position:0% +called a starvation problem okay where +some guy is sitting there for a really + + align:start position:0% +some guy is sitting there for a really + + + align:start position:0% +some guy is sitting there for a really +long time waiting while everybody else + + align:start position:0% +long time waiting while everybody else + + + align:start position:0% +long time waiting while everybody else +is continually grabbing locks out from + + align:start position:0% +is continually grabbing locks out from + + + align:start position:0% +is continually grabbing locks out from +under his or her nose okay so with a + + align:start position:0% +under his or her nose okay so with a + + + align:start position:0% +under his or her nose okay so with a +fair mutex basically what you do is you + + align:start position:0% +fair mutex basically what you do is you + + + align:start position:0% +fair mutex basically what you do is you +go for the one that's been waiting the + + align:start position:0% +go for the one that's been waiting the + + + align:start position:0% +go for the one that's been waiting the +longest essentially and so therefore you + + align:start position:0% +longest essentially and so therefore you + + + align:start position:0% +longest essentially and so therefore you +never have to wait more than for however + + align:start position:0% +never have to wait more than for however + + + align:start position:0% +never have to wait more than for however +many things were there when you got + + align:start position:0% +many things were there when you got + + + align:start position:0% +many things were there when you got +there before you're able to go question + + align:start position:0% +there before you're able to go question + + + align:start position:0% +there before you're able to go question +why + + align:start position:0% +why + + + align:start position:0% +why +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +it can be better because you may freeze + + align:start position:0% +it can be better because you may freeze + + + align:start position:0% +it can be better because you may freeze +out or service okay if there's something + + align:start position:0% +out or service okay if there's something + + + align:start position:0% +out or service okay if there's something +that's you know you may never get to do + + align:start position:0% +that's you know you may never get to do + + + align:start position:0% +that's you know you may never get to do +the thing you want to do okay because + + align:start position:0% +the thing you want to do okay because + + + align:start position:0% +the thing you want to do okay because +there's something else always + + align:start position:0% +there's something else always + + + align:start position:0% +there's something else always +interfering with the ability for that + + align:start position:0% +interfering with the ability for that + + + align:start position:0% +interfering with the ability for that +part of the program to make progress + + align:start position:0% +part of the program to make progress + + + align:start position:0% +part of the program to make progress +this tends to be more of an issue in in + + align:start position:0% +this tends to be more of an issue in in + + + align:start position:0% +this tends to be more of an issue in in +concurrent programming where we have + + align:start position:0% +concurrent programming where we have + + + align:start position:0% +concurrent programming where we have +different programs that are trying to + + align:start position:0% +different programs that are trying to + + + align:start position:0% +different programs that are trying to +accomplish different tasks and you want + + align:start position:0% +accomplish different tasks and you want + + + align:start position:0% +accomplish different tasks and you want +to accomplish both tasks okay + + align:start position:0% +to accomplish both tasks okay + + + align:start position:0% +to accomplish both tasks okay +does not come across in parallel + + align:start position:0% +does not come across in parallel + + + align:start position:0% +does not come across in parallel +programming mostly we deal with unfair + + align:start position:0% +programming mostly we deal with unfair + + + align:start position:0% +programming mostly we deal with unfair +often unfair spinning locks because + + align:start position:0% +often unfair spinning locks because + + + align:start position:0% +often unfair spinning locks because +they're the cheapest and we just trust + + align:start position:0% +they're the cheapest and we just trust + + + align:start position:0% +they're the cheapest and we just trust +that a we're not going to do any have + + align:start position:0% +that a we're not going to do any have + + + align:start position:0% +that a we're not going to do any have +any critical regions we write our code + + align:start position:0% +any critical regions we write our code + + + align:start position:0% +any critical regions we write our code +so we don't have critical regions that + + align:start position:0% +so we don't have critical regions that + + + align:start position:0% +so we don't have critical regions that +are really long so nobody ever has to + + align:start position:0% +are really long so nobody ever has to + + + align:start position:0% +are really long so nobody ever has to +wait a very long time but indeed dealing + + align:start position:0% +wait a very long time but indeed dealing + + + align:start position:0% +wait a very long time but indeed dealing +with a contention issue as we talked + + align:start position:0% +with a contention issue as we talked + + + align:start position:0% +with a contention issue as we talked +about last week you know can can make a + + align:start position:0% +about last week you know can can make a + + + align:start position:0% +about last week you know can can make a +difference okay good so here's an + + align:start position:0% +difference okay good so here's an + + + align:start position:0% +difference okay good so here's an +implementation of a simple spinning + + align:start position:0% +implementation of a simple spinning + + + align:start position:0% +implementation of a simple spinning +mutex in assembly language okay + + align:start position:0% +mutex in assembly language okay + + + align:start position:0% +mutex in assembly language okay +so the first thing it does is it checks + + align:start position:0% +so the first thing it does is it checks + + + align:start position:0% +so the first thing it does is it checks +to see if the the mutex is free if it's + + align:start position:0% +to see if the the mutex is free if it's + + + align:start position:0% +to see if the the mutex is free if it's +value is 0 so it compares the value of + + align:start position:0% +value is 0 so it compares the value of + + + align:start position:0% +value is 0 so it compares the value of +the mutex to 0 and if it is 0 it says oh + + align:start position:0% +the mutex to 0 and if it is 0 it says oh + + + align:start position:0% +the mutex to 0 and if it is 0 it says oh +the it's free let me go get it it then + + align:start position:0% +the it's free let me go get it it then + + + align:start position:0% +the it's free let me go get it it then +to get the mutex what it does is it + + align:start position:0% +to get the mutex what it does is it + + + align:start position:0% +to get the mutex what it does is it +moves one into the it basically moves + + align:start position:0% +moves one into the it basically moves + + + align:start position:0% +moves one into the it basically moves +one into a register and then it + + align:start position:0% +one into a register and then it + + + align:start position:0% +one into a register and then it +exchanges the mutex with that register + + align:start position:0% +exchanges the mutex with that register + + + align:start position:0% +exchanges the mutex with that register +EAX ok and then it compares to see + + align:start position:0% +EAX ok and then it compares to see + + + align:start position:0% +EAX ok and then it compares to see +whether or not it actually got the mutex + + align:start position:0% +whether or not it actually got the mutex + + + align:start position:0% +whether or not it actually got the mutex +and if it didn't then it goes back up to + + align:start position:0% +and if it didn't then it goes back up to + + + align:start position:0% +and if it didn't then it goes back up to +the top and starts again ok and then the + + align:start position:0% +the top and starts again ok and then the + + + align:start position:0% +the top and starts again ok and then the +other branch is at the at the top there + + align:start position:0% +other branch is at the at the top there + + + align:start position:0% +other branch is at the at the top there +it does this pause and this apparently + + align:start position:0% +it does this pause and this apparently + + + align:start position:0% +it does this pause and this apparently +is due to a bug in x86 that they end up + + align:start position:0% +is due to a bug in x86 that they end up + + + align:start position:0% +is due to a bug in x86 that they end up +having to put this pause instruction in + + align:start position:0% +having to put this pause instruction in + + + align:start position:0% +having to put this pause instruction in +there and then otherwise you jump to the + + align:start position:0% +there and then otherwise you jump to the + + + align:start position:0% +there and then otherwise you jump to the +where the spin mutex is and and go go + + align:start position:0% +where the spin mutex is and and go go + + + align:start position:0% +where the spin mutex is and and go go +again + + align:start position:0% +again + + + align:start position:0% +again +okay and then once you've done the + + align:start position:0% +okay and then once you've done the + + + align:start position:0% +okay and then once you've done the +critical section when you're done you + + align:start position:0% +critical section when you're done you + + + align:start position:0% +critical section when you're done you +free it by just setting it to zero so + + align:start position:0% +free it by just setting it to zero so + + + align:start position:0% +free it by just setting it to zero so +the question here is so the exchange + + align:start position:0% +the question here is so the exchange + + + align:start position:0% +the question here is so the exchange +instruction is a is a is an atomic + + align:start position:0% +instruction is a is a is an atomic + + + align:start position:0% +instruction is a is a is an atomic +exchange so it takes the register and + + align:start position:0% +exchange so it takes the register and + + + align:start position:0% +exchange so it takes the register and +the memory value and it swaps them and + + align:start position:0% +the memory value and it swaps them and + + + align:start position:0% +the memory value and it swaps them and +you can't have anything come in so one + + align:start position:0% +you can't have anything come in so one + + + align:start position:0% +you can't have anything come in so one +of the things that might have you + + align:start position:0% +of the things that might have you + + + align:start position:0% +of the things that might have you +confused a little bit here is wait a + + align:start position:0% +confused a little bit here is wait a + + + align:start position:0% +confused a little bit here is wait a +second I check to see if the mutex is + + align:start position:0% +second I check to see if the mutex is + + + align:start position:0% +second I check to see if the mutex is +free and then I tried to get it and to + + align:start position:0% +free and then I tried to get it and to + + + align:start position:0% +free and then I tried to get it and to +test if I was successful why why can't I + + align:start position:0% +test if I was successful why why can't I + + + align:start position:0% +test if I was successful why why can't I +just start out by essentially going to + + align:start position:0% +just start out by essentially going to + + + align:start position:0% +just start out by essentially going to +get mutex right I mean why do I need why + + align:start position:0% +get mutex right I mean why do I need why + + + align:start position:0% +get mutex right I mean why do I need why +don't need any of the code between spin + + align:start position:0% +don't need any of the code between spin + + + align:start position:0% +don't need any of the code between spin +mutex and get mutex + + align:start position:0% + + + + align:start position:0% + +right so if I just started with getting + + align:start position:0% +right so if I just started with getting + + + align:start position:0% +right so if I just started with getting +new text I would move one in I would + + align:start position:0% +new text I would move one in I would + + + align:start position:0% +new text I would move one in I would +exchange check to see if I could get it + + align:start position:0% +exchange check to see if I could get it + + + align:start position:0% +exchange check to see if I could get it +if I have it fine then I execute the + + align:start position:0% +if I have it fine then I execute the + + + align:start position:0% +if I have it fine then I execute the +internet if not okay I go back and and + + align:start position:0% +internet if not okay I go back and and + + + align:start position:0% +internet if not okay I go back and and +try again so why you know because if + + align:start position:0% +try again so why you know because if + + + align:start position:0% +try again so why you know because if +somebody has it by the way the value + + align:start position:0% +somebody has it by the way the value + + + align:start position:0% +somebody has it by the way the value +that I'm gonna get is going to be one + + align:start position:0% +that I'm gonna get is going to be one + + + align:start position:0% +that I'm gonna get is going to be one +and that's what I swapped in so I + + align:start position:0% +and that's what I swapped in so I + + + align:start position:0% +and that's what I swapped in so I +haven't changed anything I go back and I + + align:start position:0% +haven't changed anything I go back and I + + + align:start position:0% +haven't changed anything I go back and I +check again so so why do I need that + + align:start position:0% +check again so so why do I need that + + + align:start position:0% +check again so so why do I need that +first part yeah yeah maybe it's faster + + align:start position:0% +first part yeah yeah maybe it's faster + + + align:start position:0% +first part yeah yeah maybe it's faster +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so indeed it's because it's faster even + + align:start position:0% +so indeed it's because it's faster even + + + align:start position:0% +so indeed it's because it's faster even +though you're executing extra code it's + + align:start position:0% +though you're executing extra code it's + + + align:start position:0% +though you're executing extra code it's +faster tell me why it's faster and this + + align:start position:0% +faster tell me why it's faster and this + + + align:start position:0% +faster tell me why it's faster and this +tape will take you you have to think a + + align:start position:0% +tape will take you you have to think a + + + align:start position:0% +tape will take you you have to think a +little bit about the cache protocols and + + align:start position:0% +little bit about the cache protocols and + + + align:start position:0% +little bit about the cache protocols and +the invalidation issue so why is it + + align:start position:0% +the invalidation issue so why is it + + + align:start position:0% +the invalidation issue so why is it +gonna be faster yeah okay good say more + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% + + + + align:start position:0% + +yeah so so it turns out the exchange + + align:start position:0% +yeah so so it turns out the exchange + + + align:start position:0% +yeah so so it turns out the exchange +operation is like a right and so in + + align:start position:0% +operation is like a right and so in + + + align:start position:0% +operation is like a right and so in +order to do a right what do I need to do + + align:start position:0% +order to do a right what do I need to do + + + align:start position:0% +order to do a right what do I need to do +for the for the cash line that it's on + + align:start position:0% +for the for the cash line that it's on + + + align:start position:0% +for the for the cash line that it's on +to bring it in but what how does it have + + align:start position:0% +to bring it in but what how does it have + + + align:start position:0% +to bring it in but what how does it have +to be brought in remember the cash lines + + align:start position:0% +to be brought in remember the cash lines + + + align:start position:0% +to be brought in remember the cash lines +had let's let's a Matt you have to + + align:start position:0% +had let's let's a Matt you have to + + + align:start position:0% +had let's let's a Matt you have to +invalidate it on the other ones and you + + align:start position:0% +invalidate it on the other ones and you + + + align:start position:0% +invalidate it on the other ones and you +have to hold it in what state + + align:start position:0% +have to hold it in what state + + + align:start position:0% +have to hold it in what state +remember the cash lines have you know if + + align:start position:0% +remember the cash lines have you know if + + + align:start position:0% +remember the cash lines have you know if +we take a look at just a simplified + + align:start position:0% +we take a look at just a simplified + + + align:start position:0% +we take a look at just a simplified +protocol right where the MSI protocol + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +yeah you have to have it in the EMA MSI + + align:start position:0% +yeah you have to have it in the EMA MSI + + + align:start position:0% +yeah you have to have it in the EMA MSI +or an ESI you have to bring it in in + + align:start position:0% +or an ESI you have to bring it in in + + + align:start position:0% +or an ESI you have to bring it in in +modified or at least exclusive state + + align:start position:0% +modified or at least exclusive state + + + align:start position:0% +modified or at least exclusive state +right so exclusive is for the Emmy ESI + + align:start position:0% +right so exclusive is for the Emmy ESI + + + align:start position:0% +right so exclusive is for the Emmy ESI +protocol we we mentioned that but we + + align:start position:0% +protocol we we mentioned that but we + + + align:start position:0% +protocol we we mentioned that but we +didn't really do it mostly we just went + + align:start position:0% +didn't really do it mostly we just went + + + align:start position:0% +didn't really do it mostly we just went +but I have to bring it in and modified + + align:start position:0% +but I have to bring it in and modified + + + align:start position:0% +but I have to bring it in and modified +where I guarantee there are no other + + align:start position:0% +where I guarantee there are no other + + + align:start position:0% +where I guarantee there are no other +copies so if I've got two guys that are + + align:start position:0% +copies so if I've got two guys that are + + + align:start position:0% +copies so if I've got two guys that are +polling on this location + + align:start position:0% +polling on this location + + + align:start position:0% +polling on this location +they're both continually invalidating + + align:start position:0% +they're both continually invalidating + + + align:start position:0% +they're both continually invalidating +each other and you create a whole bunch + + align:start position:0% +each other and you create a whole bunch + + + align:start position:0% +each other and you create a whole bunch +of traffic on the memory network that's + + align:start position:0% +of traffic on the memory network that's + + + align:start position:0% +of traffic on the memory network that's +going to slow everything down okay + + align:start position:0% +going to slow everything down okay + + + align:start position:0% +going to slow everything down okay +whereas if I do the first one what state + + align:start position:0% +whereas if I do the first one what state + + + align:start position:0% +whereas if I do the first one what state +do I get it in then you get it in shared + + align:start position:0% +do I get it in then you get it in shared + + + align:start position:0% +do I get it in then you get it in shared +State what does the other guy get it in + + align:start position:0% +State what does the other guy get it in + + + align:start position:0% +State what does the other guy get it in +shared state and now I keep going just + + align:start position:0% +shared state and now I keep going just + + + align:start position:0% +shared state and now I keep going just +having it in spinning in my own local + + align:start position:0% +having it in spinning in my own local + + + align:start position:0% +having it in spinning in my own local +cache not generating any local traffic + + align:start position:0% +cache not generating any local traffic + + + align:start position:0% +cache not generating any local traffic +until the until somebody releases the + + align:start position:0% +until the until somebody releases the + + + align:start position:0% +until the until somebody releases the +Falak in which case it invalidate Sall + + align:start position:0% +Falak in which case it invalidate Sall + + + align:start position:0% +Falak in which case it invalidate Sall +those and now you can actually get it a + + align:start position:0% +those and now you can actually get it a + + + align:start position:0% +those and now you can actually get it a +little bit of a storm after the fact + + align:start position:0% +little bit of a storm after the fact + + + align:start position:0% +little bit of a storm after the fact +there in fact locks where you don't even + + align:start position:0% +there in fact locks where you don't even + + + align:start position:0% +there in fact locks where you don't even +get a storm after the after the fact but + + align:start position:0% +get a storm after the after the fact but + + + align:start position:0% +get a storm after the after the fact but +called mcs locks but but this kind of + + align:start position:0% +called mcs locks but but this kind of + + + align:start position:0% +called mcs locks but but this kind of +lock is for most practical purposes just + + align:start position:0% +lock is for most practical purposes just + + + align:start position:0% +lock is for most practical purposes just +fine okay so so to everybody follow that + + align:start position:0% +fine okay so so to everybody follow that + + + align:start position:0% +fine okay so so to everybody follow that +description of what's going on there so + + align:start position:0% +description of what's going on there so + + + align:start position:0% +description of what's going on there so +that first code for correctness purposes + + align:start position:0% +that first code for correctness purposes + + + align:start position:0% +that first code for correctness purposes +not important for performance it is + + align:start position:0% +not important for performance it is + + + align:start position:0% +not important for performance it is +important okay isn't it great that you + + align:start position:0% +important okay isn't it great that you + + + align:start position:0% +important okay isn't it great that you +guys can read assembly language right + + align:start position:0% + + + + align:start position:0% + +okay now suppose that this is a spinning + + align:start position:0% +okay now suppose that this is a spinning + + + align:start position:0% +okay now suppose that this is a spinning +mutex suppose that I want to do a + + align:start position:0% +mutex suppose that I want to do a + + + align:start position:0% +mutex suppose that I want to do a +yielding mutex how does this code have + + align:start position:0% +yielding mutex how does this code have + + + align:start position:0% +yielding mutex how does this code have +to change + + align:start position:0% + + + + align:start position:0% + +okay so this is a spinning one just + + align:start position:0% +okay so this is a spinning one just + + + align:start position:0% +okay so this is a spinning one just +keeps checking instead I want to return + + align:start position:0% +keeps checking instead I want to return + + + align:start position:0% +keeps checking instead I want to return +control of the operating system okay so + + align:start position:0% +control of the operating system okay so + + + align:start position:0% +control of the operating system okay so +how does this code change if I do that + + align:start position:0% +how does this code change if I do that + + + align:start position:0% +how does this code change if I do that +yeah + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +like that yeah exactly + + align:start position:0% +like that yeah exactly + + + align:start position:0% +like that yeah exactly +okay so instead of doing that that you + + align:start position:0% +okay so instead of doing that that you + + + align:start position:0% +okay so instead of doing that that you +know + + align:start position:0% +know + + + align:start position:0% +know +pause instruction which the + + align:start position:0% +pause instruction which the + + + align:start position:0% +pause instruction which the +documentation on this is not very clear + + align:start position:0% +documentation on this is not very clear + + + align:start position:0% +documentation on this is not very clear +I'm love to have the inside scoop on why + + align:start position:0% +I'm love to have the inside scoop on why + + + align:start position:0% +I'm love to have the inside scoop on why +they really had to do the pause there + + align:start position:0% +they really had to do the pause there + + + align:start position:0% +they really had to do the pause there +but in any case you take that no op that + + align:start position:0% +but in any case you take that no op that + + + align:start position:0% +but in any case you take that no op that +they want to have in there and your + + align:start position:0% +they want to have in there and your + + + align:start position:0% +they want to have in there and your +place it with it just a call to the + + align:start position:0% +place it with it just a call to the + + + align:start position:0% +place it with it just a call to the +yield which allows the operating systems + + align:start position:0% +yield which allows the operating systems + + + align:start position:0% +yield which allows the operating systems +to schedule something else and then when + + align:start position:0% +to schedule something else and then when + + + align:start position:0% +to schedule something else and then when +it's your turn again it resumes from + + align:start position:0% +it's your turn again it resumes from + + + align:start position:0% +it's your turn again it resumes from +that point okay so that's the yield so + + align:start position:0% +that point okay so that's the yield so + + + align:start position:0% +that point okay so that's the yield so +so that's the difference in the + + align:start position:0% +so that's the difference in the + + + align:start position:0% +so that's the difference in the +implementation essentially between a + + align:start position:0% +implementation essentially between a + + + align:start position:0% +implementation essentially between a +spinning mutex and a yielding mutex okay + + align:start position:0% +spinning mutex and a yielding mutex okay + + + align:start position:0% +spinning mutex and a yielding mutex okay +now there's another kind of mutex that + + align:start position:0% +now there's another kind of mutex that + + + align:start position:0% +now there's another kind of mutex that +is kind of cool which is called a + + align:start position:0% +is kind of cool which is called a + + + align:start position:0% +is kind of cool which is called a +competitive mutex so think about it this + + align:start position:0% +competitive mutex so think about it this + + + align:start position:0% +competitive mutex so think about it this +way + + align:start position:0% +way + + + align:start position:0% +way +I've competing goals one is to I want to + + align:start position:0% +I've competing goals one is to I want to + + + align:start position:0% +I've competing goals one is to I want to +get the mutex as quickly as possible + + align:start position:0% +get the mutex as quickly as possible + + + align:start position:0% +get the mutex as quickly as possible +after it's released right I don't want + + align:start position:0% +after it's released right I don't want + + + align:start position:0% +after it's released right I don't want +if if it's unlocked I don't want to sit + + align:start position:0% +if if it's unlocked I don't want to sit + + + align:start position:0% +if if it's unlocked I don't want to sit +there for a really long time and before + + align:start position:0% +there for a really long time and before + + + align:start position:0% +there for a really long time and before +I actually acquire okay and - yeah but I + + align:start position:0% +I actually acquire okay and - yeah but I + + + align:start position:0% +I actually acquire okay and - yeah but I +don't want to sit there spinning for a + + align:start position:0% +don't want to sit there spinning for a + + + align:start position:0% +don't want to sit there spinning for a +really long time and then you know + + align:start position:0% +really long time and then you know + + + align:start position:0% +really long time and then you know +because as long I'm doing that I'm + + align:start position:0% +because as long I'm doing that I'm + + + align:start position:0% +because as long I'm doing that I'm +taking up cycles and not accomplishing + + align:start position:0% +taking up cycles and not accomplishing + + + align:start position:0% +taking up cycles and not accomplishing +anything let me turn it over to some + + align:start position:0% +anything let me turn it over to some + + + align:start position:0% +anything let me turn it over to some +other thread that can can use the cycles + + align:start position:0% +other thread that can can use the cycles + + + align:start position:0% +other thread that can can use the cycles +more effectively so there at those two + + align:start position:0% +more effectively so there at those two + + + align:start position:0% +more effectively so there at those two +goals how can I get the best of both + + align:start position:0% +goals how can I get the best of both + + + align:start position:0% +goals how can I get the best of both +worlds here something that's close to + + align:start position:0% +worlds here something that's close to + + + align:start position:0% +worlds here something that's close to +the best of both worlds that's not + + align:start position:0% +the best of both worlds that's not + + + align:start position:0% +the best of both worlds that's not +absolutely the best of all flows but + + align:start position:0% +absolutely the best of all flows but + + + align:start position:0% +absolutely the best of all flows but +it's close to the best of both worlds + + align:start position:0% + + + + align:start position:0% + +what strategy could I do so I want to + + align:start position:0% +what strategy could I do so I want to + + + align:start position:0% +what strategy could I do so I want to +claim it very soon so so the point is + + align:start position:0% +claim it very soon so so the point is + + + align:start position:0% +claim it very soon so so the point is +that the spinning mutex achieves goal + + align:start position:0% +that the spinning mutex achieves goal + + + align:start position:0% +that the spinning mutex achieves goal +one and the yielding mutex achieves goal + + align:start position:0% +one and the yielding mutex achieves goal + + + align:start position:0% +one and the yielding mutex achieves goal +two so how can i what can I do to get + + align:start position:0% +two so how can i what can I do to get + + + align:start position:0% +two so how can i what can I do to get +both goals yeah + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +thank you + + align:start position:0% +thank you + + + align:start position:0% +thank you +so you're saying use message-passing to + + align:start position:0% +so you're saying use message-passing to + + + align:start position:0% +so you're saying use message-passing to +inform the waiting threads I'm thinking + + align:start position:0% +inform the waiting threads I'm thinking + + + align:start position:0% +inform the waiting threads I'm thinking +something a lot simpler + + align:start position:0% +something a lot simpler + + + align:start position:0% +something a lot simpler +okay in this context so because the + + align:start position:0% +okay in this context so because the + + + align:start position:0% +okay in this context so because the +message passing you're gonna have to go + + align:start position:0% +message passing you're gonna have to go + + + align:start position:0% +message passing you're gonna have to go +through to do message passing properly + + align:start position:0% +through to do message passing properly + + + align:start position:0% +through to do message passing properly +you actually need to use mutex as a + + align:start position:0% +you actually need to use mutex as a + + + align:start position:0% +you actually need to use mutex as a +setter to implement it so you want to be + + align:start position:0% +setter to implement it so you want to be + + + align:start position:0% +setter to implement it so you want to be +a little bit careful you know about + + align:start position:0% +a little bit careful you know about + + + align:start position:0% +a little bit careful you know about +about that but but interesting idea yeah + + align:start position:0% + + + + align:start position:0% + +using an interrupt how would you do that + + align:start position:0% + + + + align:start position:0% + +yeah so typically implement interrupts + + align:start position:0% +yeah so typically implement interrupts + + + align:start position:0% +yeah so typically implement interrupts +you also need to have some mutual + + align:start position:0% +you also need to have some mutual + + + align:start position:0% +you also need to have some mutual +exclusions to do it properly but I mean + + align:start position:0% +exclusions to do it properly but I mean + + + align:start position:0% +exclusions to do it properly but I mean +hardware will support that + + align:start position:0% +hardware will support that + + + align:start position:0% +hardware will support that +that's pretty heavy-handed as well this + + align:start position:0% +that's pretty heavy-handed as well this + + + align:start position:0% +that's pretty heavy-handed as well this +is actually a very simple solution who's + + align:start position:0% +is actually a very simple solution who's + + + align:start position:0% +is actually a very simple solution who's +everybody I'm seeing familiar hands I + + align:start position:0% +everybody I'm seeing familiar hands I + + + align:start position:0% +everybody I'm seeing familiar hands I +want to see so unfamiliar hands who's + + align:start position:0% +want to see so unfamiliar hands who's + + + align:start position:0% +want to see so unfamiliar hands who's +got an unfamiliar hand okay I see you + + align:start position:0% +got an unfamiliar hand okay I see you + + + align:start position:0% +got an unfamiliar hand okay I see you +raised your left hand that time instead + + align:start position:0% +raised your left hand that time instead + + + align:start position:0% +raised your left hand that time instead +of your right hand okay yeah + + align:start position:0% + + + + align:start position:0% + +it hard to measure that right how would + + align:start position:0% +it hard to measure that right how would + + + align:start position:0% +it hard to measure that right how would +you write code to measure that yeah + + align:start position:0% +you write code to measure that yeah + + + align:start position:0% +you write code to measure that yeah +mm-hmm yeah good okay good + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +why doesn't it have a because if I yield + + align:start position:0% +why doesn't it have a because if I yield + + + align:start position:0% +why doesn't it have a because if I yield +okay so what's the how often does if I + + align:start position:0% +okay so what's the how often does if I + + + align:start position:0% +okay so what's the how often does if I +contact switch how often is it going to + + align:start position:0% +contact switch how often is it going to + + + align:start position:0% +contact switch how often is it going to +be that I how long am I going to have to + + align:start position:0% +be that I how long am I going to have to + + + align:start position:0% +be that I how long am I going to have to +wait typically before I am scheduled + + align:start position:0% +wait typically before I am scheduled + + + align:start position:0% +wait typically before I am scheduled +again okay when when a when a code + + align:start position:0% +again okay when when a when a code + + + align:start position:0% +again okay when when a when a code +yields to the operating system how often + + align:start position:0% +yields to the operating system how often + + + align:start position:0% +yields to the operating system how often +does the operating system normally do + + align:start position:0% +does the operating system normally do + + + align:start position:0% +does the operating system normally do +context switching do you know what's + + align:start position:0% +context switching do you know what's + + + align:start position:0% +context switching do you know what's +that what's the rate at which it + + align:start position:0% +that what's the rate at which it + + + align:start position:0% +that what's the rate at which it +contacts switches for the different + + align:start position:0% +contacts switches for the different + + + align:start position:0% +contacts switches for the different +multiplexing of threads that it does on + + align:start position:0% +multiplexing of threads that it does on + + + align:start position:0% +multiplexing of threads that it does on +to on to the available processors what's + + align:start position:0% +to on to the available processors what's + + + align:start position:0% +to on to the available processors what's +the rate at which it it shifts oh this + + align:start position:0% +the rate at which it it shifts oh this + + + align:start position:0% +the rate at which it it shifts oh this +is what okay that's gonna be on the quiz + + align:start position:0% +is what okay that's gonna be on the quiz + + + align:start position:0% +is what okay that's gonna be on the quiz +okay this is a new numeracy thing yeah + + align:start position:0% +okay this is a new numeracy thing yeah + + + align:start position:0% +okay this is a new numeracy thing yeah +how do you know how frequently + + align:start position:0% + + + + align:start position:0% + +not quite but but your your you're not + + align:start position:0% +not quite but but your your you're not + + + align:start position:0% +not quite but but your your you're not +off by more than an order of magnitude + + align:start position:0% + + + + align:start position:0% + +okay so what are the typical rates that + + align:start position:0% +okay so what are the typical rates that + + + align:start position:0% +okay so what are the typical rates that +you that the system does contact + + align:start position:0% +you that the system does contact + + + align:start position:0% +you that the system does contact +switching okay so from human times it's + + align:start position:0% +switching okay so from human times it's + + + align:start position:0% +switching okay so from human times it's +the blink of an eye right so it's + + align:start position:0% +the blink of an eye right so it's + + + align:start position:0% +the blink of an eye right so it's +actually around 10 milliseconds so it + + align:start position:0% +actually around 10 milliseconds so it + + + align:start position:0% +actually around 10 milliseconds so it +would does 100 times a second some of + + align:start position:0% +would does 100 times a second some of + + + align:start position:0% +would does 100 times a second some of +them do some do 60 times a second okay + + align:start position:0% +them do some do 60 times a second okay + + + align:start position:0% +them do some do 60 times a second okay +that's how often it switches okay now + + align:start position:0% +that's how often it switches okay now + + + align:start position:0% +that's how often it switches okay now +let's say it's a hundred times the + + align:start position:0% +let's say it's a hundred times the + + + align:start position:0% +let's say it's a hundred times the +second 10 milliseconds so you're pretty + + align:start position:0% +second 10 milliseconds so you're pretty + + + align:start position:0% +second 10 milliseconds so you're pretty +close okay 10 milliseconds okay how many + + align:start position:0% +close okay 10 milliseconds okay how many + + + align:start position:0% +close okay 10 milliseconds okay how many +orders of magnitude is that from the + + align:start position:0% +orders of magnitude is that from the + + + align:start position:0% +orders of magnitude is that from the +execution of a simple instruction okay + + align:start position:0% +execution of a simple instruction okay + + + align:start position:0% +execution of a simple instruction okay +so we're going at more than a gigahertz + + align:start position:0% +so we're going at more than a gigahertz + + + align:start position:0% +so we're going at more than a gigahertz +right and so a gigahertz is 10 to the + + align:start position:0% +right and so a gigahertz is 10 to the + + + align:start position:0% +right and so a gigahertz is 10 to the +ninth and we're talking ten to the minus + + align:start position:0% +ninth and we're talking ten to the minus + + + align:start position:0% +ninth and we're talking ten to the minus +nine and we're talking ten to the minus + + align:start position:0% +nine and we're talking ten to the minus + + + align:start position:0% +nine and we're talking ten to the minus +two so that's you know 10 million + + align:start position:0% +two so that's you know 10 million + + + align:start position:0% +two so that's you know 10 million +instruction opportunities that we miss + + align:start position:0% +instruction opportunities that we miss + + + align:start position:0% +instruction opportunities that we miss +if we switch out and of course we + + align:start position:0% +if we switch out and of course we + + + align:start position:0% +if we switch out and of course we +probably only switch out for half hour + + align:start position:0% +probably only switch out for half hour + + + align:start position:0% +probably only switch out for half hour +you know where are you along the the + + align:start position:0% +you know where are you along the the + + + align:start position:0% +you know where are you along the the +thing so you're only switching out maybe + + align:start position:0% +thing so you're only switching out maybe + + + align:start position:0% +thing so you're only switching out maybe +for half assuming nothing else is going + + align:start position:0% +for half assuming nothing else is going + + + align:start position:0% +for half assuming nothing else is going +on there but that's that means you're + + align:start position:0% +on there but that's that means you're + + + align:start position:0% +on there but that's that means you're +not grabbing the lock quickly after it's + + align:start position:0% +not grabbing the lock quickly after it's + + + align:start position:0% +not grabbing the lock quickly after it's +released because you've got ten million + + align:start position:0% +released because you've got ten million + + + align:start position:0% +released because you've got ten million +instructions that are going to execute + + align:start position:0% +instructions that are going to execute + + + align:start position:0% +instructions that are going to execute +before you're gonna have a chance to + + align:start position:0% +before you're gonna have a chance to + + + align:start position:0% +before you're gonna have a chance to +come back in and grab it okay + + align:start position:0% +come back in and grab it okay + + + align:start position:0% +come back in and grab it okay +so that's why a yielding one is does not + + align:start position:0% +so that's why a yielding one is does not + + + align:start position:0% +so that's why a yielding one is does not +grab it quickly + + align:start position:0% +grab it quickly + + + align:start position:0% +grab it quickly +okay we're spinning is like we're + + align:start position:0% +okay we're spinning is like we're + + + align:start position:0% +okay we're spinning is like we're +executing this stuff at the rate of + + align:start position:0% +executing this stuff at the rate of + + + align:start position:0% +executing this stuff at the rate of +gigahertz right checking again checking + + align:start position:0% +gigahertz right checking again checking + + + align:start position:0% +gigahertz right checking again checking +and checking again okay so why so what's + + align:start position:0% +and checking again okay so why so what's + + + align:start position:0% +and checking again okay so why so what's +what's the strategy here what can I do + + align:start position:0% +what's the strategy here what can I do + + + align:start position:0% +what's the strategy here what can I do +yeah + + align:start position:0% + + + + align:start position:0% + +hey what a good idea okay okay spin for + + align:start position:0% +hey what a good idea okay okay spin for + + + align:start position:0% +hey what a good idea okay okay spin for +a while and then yield okay so the idea + + align:start position:0% +a while and then yield okay so the idea + + + align:start position:0% +a while and then yield okay so the idea +being hey if if the if the lock is + + align:start position:0% +being hey if if the if the lock is + + + align:start position:0% +being hey if if the if the lock is +really soon then I will be able to grab + + align:start position:0% +really soon then I will be able to grab + + + align:start position:0% +really soon then I will be able to grab +it immediately because I'm spinning and + + align:start position:0% +it immediately because I'm spinning and + + + align:start position:0% +it immediately because I'm spinning and +if it takes a long time for the lock to + + align:start position:0% +if it takes a long time for the lock to + + + align:start position:0% +if it takes a long time for the lock to +yield well I will yield eventually so + + align:start position:0% +yield well I will yield eventually so + + + align:start position:0% +yield well I will yield eventually so +yeah but okay how long does spin how + + align:start position:0% +yeah but okay how long does spin how + + + align:start position:0% +yeah but okay how long does spin how +long shall I spin sure + + align:start position:0% +long shall I spin sure + + + align:start position:0% +long shall I spin sure +[Music] + + align:start position:0% + + + + align:start position:0% + +yeah basically as long as a context + + align:start position:0% +yeah basically as long as a context + + + align:start position:0% +yeah basically as long as a context +switch takes okay as long as it takes to + + align:start position:0% +switch takes okay as long as it takes to + + + align:start position:0% +switch takes okay as long as it takes to +go out and come back okay and if you do + + align:start position:0% +go out and come back okay and if you do + + + align:start position:0% +go out and come back okay and if you do +that then you never wait more than twice + + align:start position:0% +that then you never wait more than twice + + + align:start position:0% +that then you never wait more than twice +the optimal time okay this is + + align:start position:0% +the optimal time okay this is + + + align:start position:0% +the optimal time okay this is +competitive analysis which the + + align:start position:0% +competitive analysis which the + + + align:start position:0% +competitive analysis which the +theoreticians have gone off there's + + align:start position:0% +theoreticians have gone off there's + + + align:start position:0% +theoreticians have gone off there's +brilliant work in competitive analysis + + align:start position:0% +brilliant work in competitive analysis + + + align:start position:0% +brilliant work in competitive analysis +so the idea here is that if the mutex is + + align:start position:0% +so the idea here is that if the mutex is + + + align:start position:0% +so the idea here is that if the mutex is +released while you're spinning then the + + align:start position:0% +released while you're spinning then the + + + align:start position:0% +released while you're spinning then the +strategy is optimal right because you + + align:start position:0% +strategy is optimal right because you + + + align:start position:0% +strategy is optimal right because you +just sat there spinning and as soon as + + align:start position:0% +just sat there spinning and as soon as + + + align:start position:0% +just sat there spinning and as soon as +was there you got it on the next cycle + + align:start position:0% +was there you got it on the next cycle + + + align:start position:0% +was there you got it on the next cycle +if the mutex is released after the yield + + align:start position:0% +if the mutex is released after the yield + + + align:start position:0% +if the mutex is released after the yield +you've already spun for equal to that so + + align:start position:0% +you've already spun for equal to that so + + + align:start position:0% +you've already spun for equal to that so +you'll come back and get it at within it + + align:start position:0% +you'll come back and get it at within it + + + align:start position:0% +you'll come back and get it at within it +most a factor of two okay this is by the + + align:start position:0% +most a factor of two okay this is by the + + + align:start position:0% +most a factor of two okay this is by the +way that the way this shows up in the + + align:start position:0% +way that the way this shows up in the + + + align:start position:0% +way that the way this shows up in the +Theory literature if you're introduced + + align:start position:0% +Theory literature if you're introduced + + + align:start position:0% +Theory literature if you're introduced +it's called the ski rental problem okay + + align:start position:0% +it's called the ski rental problem okay + + + align:start position:0% +it's called the ski rental problem okay +and here's the idea you're gonna go you + + align:start position:0% +and here's the idea you're gonna go you + + + align:start position:0% +and here's the idea you're gonna go you +know your friends are persuading you to + + align:start position:0% +know your friends are persuading you to + + + align:start position:0% +know your friends are persuading you to +go try skiing okay right snow skiing + + align:start position:0% +go try skiing okay right snow skiing + + + align:start position:0% +go try skiing okay right snow skiing +right right okay and so you say gee + + align:start position:0% +right right okay and so you say gee + + + align:start position:0% +right right okay and so you say gee +should I buy the equipment or should I + + align:start position:0% +should I buy the equipment or should I + + + align:start position:0% +should I buy the equipment or should I +rent after all you may discover it that + + align:start position:0% +rent after all you may discover it that + + + align:start position:0% +rent after all you may discover it that +you rent and then I mean you buy it and + + align:start position:0% +you rent and then I mean you buy it and + + + align:start position:0% +you rent and then I mean you buy it and +then you break your leg and never want + + align:start position:0% +then you break your leg and never want + + + align:start position:0% +then you break your leg and never want +to go back okay well then if you've + + align:start position:0% +to go back okay well then if you've + + + align:start position:0% +to go back okay well then if you've +bought it's been very expensive and if + + align:start position:0% +bought it's been very expensive and if + + + align:start position:0% +bought it's been very expensive and if +you've rented well then then you're + + align:start position:0% +you've rented well then then you're + + + align:start position:0% +you've rented well then then you're +probably better off on the other hand if + + align:start position:0% +probably better off on the other hand if + + + align:start position:0% +probably better off on the other hand if +it turns out you like it + + align:start position:0% +it turns out you like it + + + align:start position:0% +it turns out you like it +you're now accumulating the costs going + + align:start position:0% +you're now accumulating the costs going + + + align:start position:0% +you're now accumulating the costs going +forward okay and so the question is well + + align:start position:0% +forward okay and so the question is well + + + align:start position:0% +forward okay and so the question is well +what's your strategy and the idea is + + align:start position:0% +what's your strategy and the idea is + + + align:start position:0% +what's your strategy and the idea is +well let's look at what renting costs + + align:start position:0% +well let's look at what renting costs + + + align:start position:0% +well let's look at what renting costs +and what buying costs let me rent until + + align:start position:0% +and what buying costs let me rent until + + + align:start position:0% +and what buying costs let me rent until +it's equal to the cost of buying and + + align:start position:0% +it's equal to the cost of buying and + + + align:start position:0% +it's equal to the cost of buying and +then buy and then I'm within a factor of + + align:start position:0% +then buy and then I'm within a factor of + + + align:start position:0% +then buy and then I'm within a factor of +two of having spent the optimal amount + + align:start position:0% +two of having spent the optimal amount + + + align:start position:0% +two of having spent the optimal amount +of of money for because then if I break + + align:start position:0% +of of money for because then if I break + + + align:start position:0% +of of money for because then if I break +my leg after that well at least I you + + align:start position:0% +my leg after that well at least I you + + + align:start position:0% +my leg after that well at least I you +know you know I got you know I I I + + align:start position:0% +know you know I got you know I I I + + + align:start position:0% +know you know I got you know I I I +didn't spend more than a factor of two + + align:start position:0% +didn't spend more than a factor of two + + + align:start position:0% +didn't spend more than a factor of two +and if I get it before it I've spent + + align:start position:0% +and if I get it before it I've spent + + + align:start position:0% +and if I get it before it I've spent +optimally + + align:start position:0% +optimally + + + align:start position:0% +optimally +okay yeah + + align:start position:0% + + + + align:start position:0% + +yeah yeah 10 milliseconds yeah so spin + + align:start position:0% +yeah yeah 10 milliseconds yeah so spin + + + align:start position:0% +yeah yeah 10 milliseconds yeah so spin +for 10 milliseconds okay and then switch + + align:start position:0% +for 10 milliseconds okay and then switch + + + align:start position:0% +for 10 milliseconds okay and then switch +so now the point is that that when you + + align:start position:0% +so now the point is that that when you + + + align:start position:0% +so now the point is that that when you +come back in okay the other job is gonna + + align:start position:0% +come back in okay the other job is gonna + + + align:start position:0% +come back in okay the other job is gonna +run for 10 milliseconds or whatever okay + + align:start position:0% +run for 10 milliseconds or whatever okay + + + align:start position:0% +run for 10 milliseconds or whatever okay +so if you get switched out then if the + + align:start position:0% +so if you get switched out then if the + + + align:start position:0% +so if you get switched out then if the +lock is released you're gonna be done in + + align:start position:0% +lock is released you're gonna be done in + + + align:start position:0% +lock is released you're gonna be done in +20 milliseconds right and so you'll be + + align:start position:0% +20 milliseconds right and so you'll be + + + align:start position:0% +20 milliseconds right and so you'll be +within a factor of 2 and if it happened + + align:start position:0% +within a factor of 2 and if it happened + + + align:start position:0% +within a factor of 2 and if it happened +if they lock out release before then + + align:start position:0% +if they lock out release before then + + + align:start position:0% +if they lock out release before then +you're right there to grab it okay now + + align:start position:0% +you're right there to grab it okay now + + + align:start position:0% +you're right there to grab it okay now +it turns out that there's a really + + align:start position:0% +it turns out that there's a really + + + align:start position:0% +it turns out that there's a really +clever randomized algorithm I love this + + align:start position:0% +clever randomized algorithm I love this + + + align:start position:0% +clever randomized algorithm I love this +rat algorithm okay from 1994 that + + align:start position:0% +rat algorithm okay from 1994 that + + + align:start position:0% +rat algorithm okay from 1994 that +achieves a competitive ratio of e over e + + align:start position:0% +achieves a competitive ratio of e over e + + + align:start position:0% +achieves a competitive ratio of e over e +minus 1 using a randomized strategy and + + align:start position:0% +minus 1 using a randomized strategy and + + + align:start position:0% +minus 1 using a randomized strategy and +I'll encourage you to you know those of + + align:start position:0% +I'll encourage you to you know those of + + + align:start position:0% +I'll encourage you to you know those of +you who have a theoretical bent to go + + align:start position:0% +you who have a theoretical bent to go + + + align:start position:0% +you who have a theoretical bent to go +take a look at that it's very clever + + align:start position:0% +take a look at that it's very clever + + + align:start position:0% +take a look at that it's very clever +ok so basically have some probability of + + align:start position:0% +ok so basically have some probability of + + + align:start position:0% +ok so basically have some probability of +at every step of whether you at that + + align:start position:0% +at every step of whether you at that + + + align:start position:0% +at every step of whether you at that +point decide to yield you know or + + align:start position:0% +point decide to yield you know or + + + align:start position:0% +point decide to yield you know or +continue spinning ok and by using a + + align:start position:0% +continue spinning ok and by using a + + + align:start position:0% +continue spinning ok and by using a +randomized strategy you can actually get + + align:start position:0% +randomized strategy you can actually get + + + align:start position:0% +randomized strategy you can actually get +this to Yi over u minus 1 ok questions + + align:start position:0% +this to Yi over u minus 1 ok questions + + + align:start position:0% +this to Yi over u minus 1 ok questions +about this so this is sort of some of + + align:start position:0% +about this so this is sort of some of + + + align:start position:0% +about this so this is sort of some of +the basics I'm glad we went over some of + + align:start position:0% +the basics I'm glad we went over some of + + + align:start position:0% +the basics I'm glad we went over some of +that because everybody should know these + + align:start position:0% +that because everybody should know these + + + align:start position:0% +that because everybody should know these +basic numbers about what things cost + + align:start position:0% +basic numbers about what things cost + + + align:start position:0% +basic numbers about what things cost +because otherwise you don't know where + + align:start position:0% +because otherwise you don't know where + + + align:start position:0% +because otherwise you don't know where +to spend it so context switching time is + + align:start position:0% +to spend it so context switching time is + + + align:start position:0% +to spend it so context switching time is +on the order of 10 milliseconds how long + + align:start position:0% +on the order of 10 milliseconds how long + + + align:start position:0% +on the order of 10 milliseconds how long +is the disk access compared to you know + + align:start position:0% +is the disk access compared to you know + + + align:start position:0% +is the disk access compared to you know +yeah what's the disk access + + align:start position:0% + + + + align:start position:0% + +150 cycles hmm that's an that that would + + align:start position:0% +150 cycles hmm that's an that that would + + + align:start position:0% +150 cycles hmm that's an that that would +be accessing DRAM okay + + align:start position:0% +be accessing DRAM okay + + + align:start position:0% +be accessing DRAM okay +accessing DRAM if you if it wasn't in + + align:start position:0% +accessing DRAM if you if it wasn't in + + + align:start position:0% +accessing DRAM if you if it wasn't in +cache might be 150 cycles okay + + align:start position:0% +cache might be 150 cycles okay + + + align:start position:0% +cache might be 150 cycles okay +so two orders of magnitude or so okay so + + align:start position:0% +so two orders of magnitude or so okay so + + + align:start position:0% +so two orders of magnitude or so okay so +what what about a disk access how long + + align:start position:0% +what what about a disk access how long + + + align:start position:0% +what what about a disk access how long +is that take yeah + + align:start position:0% +is that take yeah + + + align:start position:0% +is that take yeah +yes several milliseconds so ten + + align:start position:0% +yes several milliseconds so ten + + + align:start position:0% +yes several milliseconds so ten +milliseconds that are five milliseconds + + align:start position:0% +milliseconds that are five milliseconds + + + align:start position:0% +milliseconds that are five milliseconds +depend upon how fast your disk is but + + align:start position:0% +depend upon how fast your disk is but + + + align:start position:0% +depend upon how fast your disk is but +once again it's on the order of + + align:start position:0% +once again it's on the order of + + + align:start position:0% +once again it's on the order of +milliseconds so it's helpful to know + + align:start position:0% +milliseconds so it's helpful to know + + + align:start position:0% +milliseconds so it's helpful to know +some of these numbers because otherwise + + align:start position:0% +some of these numbers because otherwise + + + align:start position:0% +some of these numbers because otherwise +you know where are you spending your + + align:start position:0% +you know where are you spending your + + + align:start position:0% +you know where are you spending your +time especially we're sort of doing + + align:start position:0% +time especially we're sort of doing + + + align:start position:0% +time especially we're sort of doing +performance engineering you know in the + + align:start position:0% +performance engineering you know in the + + + align:start position:0% +performance engineering you know in the +small basically looking within the + + align:start position:0% +small basically looking within the + + + align:start position:0% +small basically looking within the +product you know within a multi-core + + align:start position:0% +product you know within a multi-core + + + align:start position:0% +product you know within a multi-core +processor most performance engineering + + align:start position:0% +processor most performance engineering + + + align:start position:0% +processor most performance engineering +is on all the stuff on the outside + + align:start position:0% +is on all the stuff on the outside + + + align:start position:0% +is on all the stuff on the outside +dealing with networking and file systems + + align:start position:0% +dealing with networking and file systems + + + align:start position:0% +dealing with networking and file systems +and stuff where where things are really + + align:start position:0% +and stuff where where things are really + + + align:start position:0% +and stuff where where things are really +costly and where you actually have a lot + + align:start position:0% +costly and where you actually have a lot + + + align:start position:0% +costly and where you actually have a lot +of time you can write fast piece of code + + align:start position:0% +of time you can write fast piece of code + + + align:start position:0% +of time you can write fast piece of code +that can figure out how you should best + + align:start position:0% +that can figure out how you should best + + + align:start position:0% +that can figure out how you should best +deal with these slow parts of your + + align:start position:0% +deal with these slow parts of your + + + align:start position:0% +deal with these slow parts of your +system okay so those are all sort of + + align:start position:0% +system okay so those are all sort of + + + align:start position:0% +system okay so those are all sort of +good numbers to know you'll probably see + + align:start position:0% +good numbers to know you'll probably see + + + align:start position:0% +good numbers to know you'll probably see +some of them on quiz 2 okay okay + + align:start position:0% +some of them on quiz 2 okay okay + + + align:start position:0% +some of them on quiz 2 okay okay +deadlock I mentioned deadlock earlier + + align:start position:0% +deadlock I mentioned deadlock earlier + + + align:start position:0% +deadlock I mentioned deadlock earlier +let's talk about what deadlock is and + + align:start position:0% +let's talk about what deadlock is and + + + align:start position:0% +let's talk about what deadlock is and +understand this once again I expect some + + align:start position:0% +understand this once again I expect some + + + align:start position:0% +understand this once again I expect some +of you have seen this but I still want + + align:start position:0% +of you have seen this but I still want + + + align:start position:0% +of you have seen this but I still want +to go through it because it's hugely + + align:start position:0% +to go through it because it's hugely + + + align:start position:0% +to go through it because it's hugely +important material and this is the issue + + align:start position:0% +important material and this is the issue + + + align:start position:0% +important material and this is the issue +that holding more than one lock at a + + align:start position:0% +that holding more than one lock at a + + + align:start position:0% +that holding more than one lock at a +time can be dangerous okay so imagine + + align:start position:0% +time can be dangerous okay so imagine + + + align:start position:0% +time can be dangerous okay so imagine +that thread one says I'm gonna lock a + + align:start position:0% +that thread one says I'm gonna lock a + + + align:start position:0% +that thread one says I'm gonna lock a +lock B execute the crudo section unlock + + align:start position:0% +lock B execute the crudo section unlock + + + align:start position:0% +lock B execute the crudo section unlock +B unlock a where a and B or mutexes and + + align:start position:0% +B unlock a where a and B or mutexes and + + + align:start position:0% +B unlock a where a and B or mutexes and +thread two does something very similar + + align:start position:0% +thread two does something very similar + + + align:start position:0% +thread two does something very similar +it locks B and locks a then it does the + + align:start position:0% +it locks B and locks a then it does the + + + align:start position:0% +it locks B and locks a then it does the +critical section then it unlocks a and + + align:start position:0% +critical section then it unlocks a and + + + align:start position:0% +critical section then it unlocks a and +then unlocks B okay so what can happen + + align:start position:0% +then unlocks B okay so what can happen + + + align:start position:0% +then unlocks B okay so what can happen +here so we you know thread one locks a + + align:start position:0% +here so we you know thread one locks a + + + align:start position:0% +here so we you know thread one locks a +thread two locks B thread + + align:start position:0% + + + + align:start position:0% + +one can't go and lock be because thread + + align:start position:0% +one can't go and lock be because thread + + + align:start position:0% +one can't go and lock be because thread +two has it thread two can't go and lock + + align:start position:0% +two has it thread two can't go and lock + + + align:start position:0% +two has it thread two can't go and lock +a because thread one has it so they sit + + align:start position:0% +a because thread one has it so they sit + + + align:start position:0% +a because thread one has it so they sit +there blocked I don't care if they're + + align:start position:0% +there blocked I don't care if they're + + + align:start position:0% +there blocked I don't care if they're +spinning or yielding they're not going + + align:start position:0% +spinning or yielding they're not going + + + align:start position:0% +spinning or yielding they're not going +anywhere okay so this is the ultimate + + align:start position:0% +anywhere okay so this is the ultimate + + + align:start position:0% +anywhere okay so this is the ultimate +loss of performance right it's like it's + + align:start position:0% +loss of performance right it's like it's + + + align:start position:0% +loss of performance right it's like it's +incorrect okay it's like you're stuck + + align:start position:0% +incorrect okay it's like you're stuck + + + align:start position:0% +incorrect okay it's like you're stuck +you've deadlocked okay now there's + + align:start position:0% +you've deadlocked okay now there's + + + align:start position:0% +you've deadlocked okay now there's +there's three basic conditions for + + align:start position:0% +there's three basic conditions for + + + align:start position:0% +there's three basic conditions for +deadlock everybody understands this + + align:start position:0% +deadlock everybody understands this + + + align:start position:0% +deadlock everybody understands this +right there's there any anybody who has + + align:start position:0% +right there's there any anybody who has + + + align:start position:0% +right there's there any anybody who has +a question because just okay it's + + align:start position:0% +a question because just okay it's + + + align:start position:0% +a question because just okay it's +there's three conditions you need for + + align:start position:0% +there's three conditions you need for + + + align:start position:0% +there's three conditions you need for +deadlock the first one is mutual + + align:start position:0% +deadlock the first one is mutual + + + align:start position:0% +deadlock the first one is mutual +exclusion that you're going to have + + align:start position:0% +exclusion that you're going to have + + + align:start position:0% +exclusion that you're going to have +exclusive control over the resources the + + align:start position:0% +exclusive control over the resources the + + + align:start position:0% +exclusive control over the resources the +second is non preemption you don't + + align:start position:0% +second is non preemption you don't + + + align:start position:0% +second is non preemption you don't +release your resources you hold until + + align:start position:0% +release your resources you hold until + + + align:start position:0% +release your resources you hold until +you finish using them okay and and three + + align:start position:0% +you finish using them okay and and three + + + align:start position:0% +you finish using them okay and and three +is circular waiting you have a cycle of + + align:start position:0% +is circular waiting you have a cycle of + + + align:start position:0% +is circular waiting you have a cycle of +threads in which each thread is blocked + + align:start position:0% +threads in which each thread is blocked + + + align:start position:0% +threads in which each thread is blocked +waiting for resources held by the next + + align:start position:0% +waiting for resources held by the next + + + align:start position:0% +waiting for resources held by the next +one in this case the resource is the + + align:start position:0% +one in this case the resource is the + + + align:start position:0% +one in this case the resource is the +lock okay and so if you remove any one + + align:start position:0% +lock okay and so if you remove any one + + + align:start position:0% +lock okay and so if you remove any one +of these constraints okay you can come + + align:start position:0% +of these constraints okay you can come + + + align:start position:0% +of these constraints okay you can come +up with solutions that won't deadlock so + + align:start position:0% +up with solutions that won't deadlock so + + + align:start position:0% +up with solutions that won't deadlock so +for example it could be that when I try + + align:start position:0% +for example it could be that when I try + + + align:start position:0% +for example it could be that when I try +to acquire a lock if somebody else has + + align:start position:0% +to acquire a lock if somebody else has + + + align:start position:0% +to acquire a lock if somebody else has +him I take it away + + align:start position:0% +him I take it away + + + align:start position:0% +him I take it away +okay you know that could be one thing + + align:start position:0% +okay you know that could be one thing + + + align:start position:0% +okay you know that could be one thing +now there may get into other issues + + align:start position:0% +now there may get into other issues + + + align:start position:0% +now there may get into other issues +which is like well but what if he's + + align:start position:0% +which is like well but what if he's + + + align:start position:0% +which is like well but what if he's +actually doing real work okay + + align:start position:0% +actually doing real work okay + + + align:start position:0% +actually doing real work okay +or whatever so all of these things have + + align:start position:0% +or whatever so all of these things have + + + align:start position:0% +or whatever so all of these things have +things or you know I don't insist that + + align:start position:0% +things or you know I don't insist that + + + align:start position:0% +things or you know I don't insist that +it be mutual exclusion except that's the + + align:start position:0% +it be mutual exclusion except that's the + + + align:start position:0% +it be mutual exclusion except that's the +kind of problem that we're trying to + + align:start position:0% +kind of problem that we're trying to + + + align:start position:0% +kind of problem that we're trying to +solve so these are generally the three + + align:start position:0% +solve so these are generally the three + + + align:start position:0% +solve so these are generally the three +things that are necessary in order to in + + align:start position:0% +things that are necessary in order to in + + + align:start position:0% +things that are necessary in order to in +order to have a deadlock situation now + + align:start position:0% +order to have a deadlock situation now + + + align:start position:0% +order to have a deadlock situation now +in any discussion of deadlock you have + + align:start position:0% +in any discussion of deadlock you have + + + align:start position:0% +in any discussion of deadlock you have +to talk about dining philosophers when I + + align:start position:0% +to talk about dining philosophers when I + + + align:start position:0% +to talk about dining philosophers when I +was an undergraduate and I graduated in + + align:start position:0% +was an undergraduate and I graduated in + + + align:start position:0% +was an undergraduate and I graduated in +1975 from Yale humanities school + + align:start position:0% + + + + align:start position:0% + +I was taught the dining philosophers + + align:start position:0% +I was taught the dining philosophers + + + align:start position:0% +I was taught the dining philosophers +right because after all philosophy is + + align:start position:0% +right because after all philosophy is + + + align:start position:0% +right because after all philosophy is +what you find at humanity schools I mean + + align:start position:0% +what you find at humanity schools I mean + + + align:start position:0% +what you find at humanity schools I mean +we have philosophy department - don't + + align:start position:0% +we have philosophy department - don't + + + align:start position:0% +we have philosophy department - don't +get me wrong but at Yale the humanities + + align:start position:0% +get me wrong but at Yale the humanities + + + align:start position:0% +get me wrong but at Yale the humanities +is huge and so philosophy I guess they + + align:start position:0% +is huge and so philosophy I guess they + + + align:start position:0% +is huge and so philosophy I guess they +thought this was would appeal to the + + align:start position:0% +thought this was would appeal to the + + + align:start position:0% +thought this was would appeal to the +people who were not real techies in the + + align:start position:0% +people who were not real techies in the + + + align:start position:0% +people who were not real techies in the +background I sort of like I was a techie + + align:start position:0% +background I sort of like I was a techie + + + align:start position:0% +background I sort of like I was a techie +in the midst of all these you know + + align:start position:0% +in the midst of all these you know + + + align:start position:0% +in the midst of all these you know +non-technical people dining philosophers + + align:start position:0% +non-technical people dining philosophers + + + align:start position:0% +non-technical people dining philosophers +is a story of deadlock told by Tony + + align:start position:0% +is a story of deadlock told by Tony + + + align:start position:0% +is a story of deadlock told by Tony +Hoare based on an examination question + + align:start position:0% +Hoare based on an examination question + + + align:start position:0% +Hoare based on an examination question +by Edsger Dijkstra okay + + align:start position:0% +by Edsger Dijkstra okay + + + align:start position:0% +by Edsger Dijkstra okay +and it's been embellished too over the + + align:start position:0% +and it's been embellished too over the + + + align:start position:0% +and it's been embellished too over the +years by many many many retailers okay + + align:start position:0% +years by many many many retailers okay + + + align:start position:0% +years by many many many retailers okay +and I like the Chinese version of this + + align:start position:0% +and I like the Chinese version of this + + + align:start position:0% +and I like the Chinese version of this +okay there's versions where they use + + align:start position:0% +okay there's versions where they use + + + align:start position:0% +okay there's versions where they use +Forks but I'm going to this is going to + + align:start position:0% +Forks but I'm going to this is going to + + + align:start position:0% +Forks but I'm going to this is going to +be their dining I'm going to say that + + align:start position:0% +be their dining I'm going to say that + + + align:start position:0% +be their dining I'm going to say that +they are eating noodles with chopsticks + + align:start position:0% +they are eating noodles with chopsticks + + + align:start position:0% +they are eating noodles with chopsticks +and they're in philosophers seated + + align:start position:0% +and they're in philosophers seated + + + align:start position:0% +and they're in philosophers seated +around the table and II and between + + align:start position:0% +around the table and II and between + + + align:start position:0% +around the table and II and between +every plate of noodles there's a + + align:start position:0% +every plate of noodles there's a + + + align:start position:0% +every plate of noodles there's a +chopstick and so in order to eat the + + align:start position:0% +chopstick and so in order to eat the + + + align:start position:0% +chopstick and so in order to eat the +noodles they need two chopsticks okay + + align:start position:0% +noodles they need two chopsticks okay + + + align:start position:0% +noodles they need two chopsticks okay +which to me sounds very natural okay and + + align:start position:0% +which to me sounds very natural okay and + + + align:start position:0% +which to me sounds very natural okay and +so here's the code for philosopher I so + + align:start position:0% +so here's the code for philosopher I so + + + align:start position:0% +so here's the code for philosopher I so +he's a philosopher so he starts by + + align:start position:0% +he's a philosopher so he starts by + + + align:start position:0% +he's a philosopher so he starts by +thinking for a while okay and then he + + align:start position:0% +thinking for a while okay and then he + + + align:start position:0% +thinking for a while okay and then he +gets hungry he or she gets hungry so the + + align:start position:0% +gets hungry he or she gets hungry so the + + + align:start position:0% +gets hungry he or she gets hungry so the +philosopher grabs the chopstick on the + + align:start position:0% +philosopher grabs the chopstick on the + + + align:start position:0% +philosopher grabs the chopstick on the +law right on the Left sorry and then it + + align:start position:0% +law right on the Left sorry and then it + + + align:start position:0% +law right on the Left sorry and then it +grabs the one on the on the right but it + + align:start position:0% +grabs the one on the on the right but it + + + align:start position:0% +grabs the one on the on the right but it +had you know so which is I plus one but + + align:start position:0% +had you know so which is I plus one but + + + align:start position:0% +had you know so which is I plus one but +it has to do that mod in because if it's + + align:start position:0% +it has to do that mod in because if it's + + + align:start position:0% +it has to do that mod in because if it's +the last one you got to go around and + + align:start position:0% +the last one you got to go around and + + + align:start position:0% +the last one you got to go around and +grab the first one then eats and then it + + align:start position:0% +grab the first one then eats and then it + + + align:start position:0% +grab the first one then eats and then it +unlocks the two chopsticks and now they + + align:start position:0% +unlocks the two chopsticks and now they + + + align:start position:0% +unlocks the two chopsticks and now they +can be used by the other dining + + align:start position:0% +can be used by the other dining + + + align:start position:0% +can be used by the other dining +philosophers because they don't think + + align:start position:0% +philosophers because they don't think + + + align:start position:0% +philosophers because they don't think +much about sanitation and + + align:start position:0% +much about sanitation and + + + align:start position:0% +much about sanitation and +and so forth right so they're because + + align:start position:0% +and so forth right so they're because + + + align:start position:0% +and so forth right so they're because +they're they're too busy thinking right + + align:start position:0% +they're they're too busy thinking right + + + align:start position:0% +they're they're too busy thinking right +but but what happens what's wrong with + + align:start position:0% +but but what happens what's wrong with + + + align:start position:0% +but but what happens what's wrong with +this solution what happens what can + + align:start position:0% +this solution what happens what can + + + align:start position:0% +this solution what happens what can +happen for this it's very simple I need + + align:start position:0% +happen for this it's very simple I need + + + align:start position:0% +happen for this it's very simple I need +two chopsticks I grab one I grab the + + align:start position:0% +two chopsticks I grab one I grab the + + + align:start position:0% +two chopsticks I grab one I grab the +other I eat one day what happens yeah + + align:start position:0% + + + + align:start position:0% + +yeah they're all it and they grab one to + + align:start position:0% +yeah they're all it and they grab one to + + + align:start position:0% +yeah they're all it and they grab one to +the left and now they go to the right + + align:start position:0% +the left and now they go to the right + + + align:start position:0% +the left and now they go to the right +it's not there and they starve okay you + + align:start position:0% +it's not there and they starve okay you + + + align:start position:0% +it's not there and they starve okay you +know one day they got all the things so + + align:start position:0% +know one day they got all the things so + + + align:start position:0% +know one day they got all the things so +we have the starving philosophers + + align:start position:0% +we have the starving philosophers + + + align:start position:0% +we have the starving philosophers +problem so so be motivated by this + + align:start position:0% +problem so so be motivated by this + + + align:start position:0% +problem so so be motivated by this +problem yeah question yeah so if you are + + align:start position:0% +problem yeah question yeah so if you are + + + align:start position:0% +problem yeah question yeah so if you are +willing to preempt then that would be + + align:start position:0% +willing to preempt then that would be + + + align:start position:0% +willing to preempt then that would be +preemption as I say it's got to be non + + align:start position:0% +preemption as I say it's got to be non + + + align:start position:0% +preemption as I say it's got to be non +pre-emptive in order for deadlock to + + align:start position:0% +pre-emptive in order for deadlock to + + + align:start position:0% +pre-emptive in order for deadlock to +occur in this case yeah but you also + + align:start position:0% +occur in this case yeah but you also + + + align:start position:0% +occur in this case yeah but you also +have to worry in those cases could be oh + + align:start position:0% +have to worry in those cases could be oh + + + align:start position:0% +have to worry in those cases could be oh +well if I couldn't get both let me put + + align:start position:0% +well if I couldn't get both let me put + + + align:start position:0% +well if I couldn't get both let me put +them both down but then you can have a + + align:start position:0% +them both down but then you can have a + + + align:start position:0% +them both down but then you can have a +thing that's called livelock okay so + + align:start position:0% +thing that's called livelock okay so + + + align:start position:0% +thing that's called livelock okay so +they all pick up their left they see the + + align:start position:0% +they all pick up their left they see the + + + align:start position:0% +they all pick up their left they see the +right ones busy so they put it down so + + align:start position:0% +right ones busy so they put it down so + + + align:start position:0% +right ones busy so they put it down so +somebody else can have it they look + + align:start position:0% +somebody else can have it they look + + + align:start position:0% +somebody else can have it they look +around oh okay let me pick out one no no + + align:start position:0% +around oh okay let me pick out one no no + + + align:start position:0% +around oh okay let me pick out one no no +okay okay and so they still starve even + + align:start position:0% +okay okay and so they still starve even + + + align:start position:0% +okay okay and so they still starve even +though they've done that so in that kind + + align:start position:0% +though they've done that so in that kind + + + align:start position:0% +though they've done that so in that kind +of situation you could put in a time + + align:start position:0% +of situation you could put in a time + + + align:start position:0% +of situation you could put in a time +delay you could say let me let everybody + + align:start position:0% +delay you could say let me let everybody + + + align:start position:0% +delay you could say let me let everybody +pick a random number have a randomized + + align:start position:0% +pick a random number have a randomized + + + align:start position:0% +pick a random number have a randomized +scheme so that we're not you know so + + align:start position:0% +scheme so that we're not you know so + + + align:start position:0% +scheme so that we're not you know so +there are other solutions if you don't + + align:start position:0% +there are other solutions if you don't + + + align:start position:0% +there are other solutions if you don't +insist on non preemption I'm going to + + align:start position:0% +insist on non preemption I'm going to + + + align:start position:0% +insist on non preemption I'm going to +give you one where we have non + + align:start position:0% +give you one where we have non + + + align:start position:0% +give you one where we have non +preemption but we still avoid deadlock + + align:start position:0% +preemption but we still avoid deadlock + + + align:start position:0% +preemption but we still avoid deadlock +and it's to go for that cyclic problem + + align:start position:0% +and it's to go for that cyclic problem + + + align:start position:0% +and it's to go for that cyclic problem +so here's the idea + + align:start position:0% +so here's the idea + + + align:start position:0% +so here's the idea +suppose that we can linearly order the + + align:start position:0% +suppose that we can linearly order the + + + align:start position:0% +suppose that we can linearly order the +mutexes okay so I pick some order of the + + align:start position:0% +mutexes okay so I pick some order of the + + + align:start position:0% +mutexes okay so I pick some order of the +mutexes so that whenever a thread holds + + align:start position:0% +mutexes so that whenever a thread holds + + + align:start position:0% +mutexes so that whenever a thread holds +a mutex else of I and attempts to act a + + align:start position:0% +a mutex else of I and attempts to act a + + + align:start position:0% +a mutex else of I and attempts to act a +lock another mutex l sub J we have that + + align:start position:0% +lock another mutex l sub J we have that + + + align:start position:0% +lock another mutex l sub J we have that +in this linear order L sub I comes + + align:start position:0% +in this linear order L sub I comes + + + align:start position:0% +in this linear order L sub I comes +before L sub J then you can't have a + + align:start position:0% +before L sub J then you can't have a + + + align:start position:0% +before L sub J then you can't have a +deadlock okay so in this case for the + + align:start position:0% +deadlock okay so in this case for the + + + align:start position:0% +deadlock okay so in this case for the +dining philosophers it would for example + + align:start position:0% +dining philosophers it would for example + + + align:start position:0% +dining philosophers it would for example +number the number of the chopsticks you + + align:start position:0% +number the number of the chopsticks you + + + align:start position:0% +number the number of the chopsticks you +know from 1 to N and then or 0 to n + + align:start position:0% +know from 1 to N and then or 0 to n + + + align:start position:0% +know from 1 to N and then or 0 to n +minus 1 whatever and then grab the + + align:start position:0% +minus 1 whatever and then grab the + + + align:start position:0% +minus 1 whatever and then grab the +smaller one and then grab the larger one + + align:start position:0% +smaller one and then grab the larger one + + + align:start position:0% +smaller one and then grab the larger one +then then it says then you would never + + align:start position:0% +then then it says then you would never + + + align:start position:0% +then then it says then you would never +have a deadlock + + align:start position:0% +have a deadlock + + + align:start position:0% +have a deadlock +okay and so here's the proof you know I + + align:start position:0% +okay and so here's the proof you know I + + + align:start position:0% +okay and so here's the proof you know I +like proofs okay + + align:start position:0% +like proofs okay + + + align:start position:0% +like proofs okay +proofs are really important so I'm going + + align:start position:0% +proofs are really important so I'm going + + + align:start position:0% +proofs are really important so I'm going +to show you that if you do that you + + align:start position:0% +to show you that if you do that you + + + align:start position:0% +to show you that if you do that you +couldn't have a cycle of waiting so + + align:start position:0% +couldn't have a cycle of waiting so + + + align:start position:0% +couldn't have a cycle of waiting so +suppose you had a cycle of waiting we + + align:start position:0% +suppose you had a cycle of waiting we + + + align:start position:0% +suppose you had a cycle of waiting we +were in a situation where everybody is + + align:start position:0% +were in a situation where everybody is + + + align:start position:0% +were in a situation where everybody is +holding chopsticks and you know one that + + align:start position:0% +holding chopsticks and you know one that + + + align:start position:0% +holding chopsticks and you know one that +one of them is waiting for another one + + align:start position:0% +one of them is waiting for another one + + + align:start position:0% +one of them is waiting for another one +which is waiting for now all the way + + align:start position:0% +which is waiting for now all the way + + + align:start position:0% +which is waiting for now all the way +around to the first one that's what we + + align:start position:0% +around to the first one that's what we + + + align:start position:0% +around to the first one that's what we +need for deadlock to occur so let me + + align:start position:0% +need for deadlock to occur so let me + + + align:start position:0% +need for deadlock to occur so let me +just look at what's the largest mutex on + + align:start position:0% +just look at what's the largest mutex on + + + align:start position:0% +just look at what's the largest mutex on +the cycle let's call that L max okay and + + align:start position:0% +the cycle let's call that L max okay and + + + align:start position:0% +the cycle let's call that L max okay and +suppose that it's waiting on a mutex L + + align:start position:0% +suppose that it's waiting on a mutex L + + + align:start position:0% +suppose that it's waiting on a mutex L +held by the next thread in the cycle + + align:start position:0% +held by the next thread in the cycle + + + align:start position:0% +held by the next thread in the cycle +well then we have a something that's + + align:start position:0% +well then we have a something that's + + + align:start position:0% +well then we have a something that's +bigger than the maximum one okay and so + + align:start position:0% +bigger than the maximum one okay and so + + + align:start position:0% +bigger than the maximum one okay and so +that contradicts the fact that I grabbed + + align:start position:0% +that contradicts the fact that I grabbed + + + align:start position:0% +that contradicts the fact that I grabbed +them whenever I grabbed them I do it in + + align:start position:0% +them whenever I grabbed them I do it in + + + align:start position:0% +them whenever I grabbed them I do it in +order okay so very simple very simple + + align:start position:0% +order okay so very simple very simple + + + align:start position:0% +order okay so very simple very simple +proof that you can't have deadlock if + + align:start position:0% +proof that you can't have deadlock if + + + align:start position:0% +proof that you can't have deadlock if +you grab them according to a linear + + align:start position:0% +you grab them according to a linear + + + align:start position:0% +you grab them according to a linear +order okay and so for this particular + + align:start position:0% +order okay and so for this particular + + + align:start position:0% +order okay and so for this particular +problem what I do is instead of grabbing + + align:start position:0% +problem what I do is instead of grabbing + + + align:start position:0% +problem what I do is instead of grabbing +the one on the left and one on the right + + align:start position:0% +the one on the left and one on the right + + + align:start position:0% +the one on the left and one on the right +as I say you grab the smaller of the two + + align:start position:0% +as I say you grab the smaller of the two + + + align:start position:0% +as I say you grab the smaller of the two +and then grab the larger of the two and + + align:start position:0% +and then grab the larger of the two and + + + align:start position:0% +and then grab the larger of the two and +then you're guaranteed to have no + + align:start position:0% +then you're guaranteed to have no + + + align:start position:0% +then you're guaranteed to have no +deadlock does that make sense now if + + align:start position:0% +deadlock does that make sense now if + + + align:start position:0% +deadlock does that make sense now if +you're going to use locks in silk you + + align:start position:0% +you're going to use locks in silk you + + + align:start position:0% +you're going to use locks in silk you +have to realize that in the operating + + align:start position:0% +have to realize that in the operating + + + align:start position:0% +have to realize that in the operating +sin the runtime system of silk they're + + align:start position:0% +sin the runtime system of silk they're + + + align:start position:0% +sin the runtime system of silk they're +doing they're using locks you can't see + + align:start position:0% +doing they're using locks you can't see + + + align:start position:0% +doing they're using locks you can't see +them they're encapsulated as we talked + + align:start position:0% +them they're encapsulated as we talked + + + align:start position:0% +them they're encapsulated as we talked +about the non determinism in silk is + + align:start position:0% +about the non determinism in silk is + + + align:start position:0% +about the non determinism in silk is +capsulated is still going on underneath + + align:start position:0% +capsulated is still going on underneath + + + align:start position:0% +capsulated is still going on underneath +the color covers and if you start + + align:start position:0% +the color covers and if you start + + + align:start position:0% +the color covers and if you start +introducing your own non determinism + + align:start position:0% +introducing your own non determinism + + + align:start position:0% +introducing your own non determinism +through the use of locks you can run + + align:start position:0% +through the use of locks you can run + + + align:start position:0% +through the use of locks you can run +into trouble if you're not careful and + + align:start position:0% +into trouble if you're not careful and + + + align:start position:0% +into trouble if you're not careful and +let me give you an example okay this is + + align:start position:0% +let me give you an example okay this is + + + align:start position:0% +let me give you an example okay this is +a situation you can deadlock your + + align:start position:0% +a situation you can deadlock your + + + align:start position:0% +a situation you can deadlock your +program in silk okay with just one lock + + align:start position:0% +program in silk okay with just one lock + + + align:start position:0% +program in silk okay with just one lock +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so here's an example of a code that does + + align:start position:0% +so here's an example of a code that does + + + align:start position:0% +so here's an example of a code that does +that so main spawns off foo and foo + + align:start position:0% +that so main spawns off foo and foo + + + align:start position:0% +that so main spawns off foo and foo +basically locks the lock L and then + + align:start position:0% +basically locks the lock L and then + + + align:start position:0% +basically locks the lock L and then +unlocks it and meanwhile + + align:start position:0% +unlocks it and meanwhile + + + align:start position:0% +unlocks it and meanwhile +after it spawns our food the + + align:start position:0% +after it spawns our food the + + + align:start position:0% +after it spawns our food the +continuation goes and it locks L itself + + align:start position:0% +continuation goes and it locks L itself + + + align:start position:0% +continuation goes and it locks L itself +and then does a sink and then it unlocks + + align:start position:0% +and then does a sink and then it unlocks + + + align:start position:0% +and then does a sink and then it unlocks +it so what happens here we sort of have + + align:start position:0% +it so what happens here we sort of have + + + align:start position:0% +it so what happens here we sort of have +a situation like this where where the + + align:start position:0% +a situation like this where where the + + + align:start position:0% +a situation like this where where the +locking I've done with an open bracket + + align:start position:0% +locking I've done with an open bracket + + + align:start position:0% +locking I've done with an open bracket +and an unlock a release I'm doing with a + + align:start position:0% +and an unlock a release I'm doing with a + + + align:start position:0% +and an unlock a release I'm doing with a +closed bracket so I'm spawning off foo + + align:start position:0% +closed bracket so I'm spawning off foo + + + align:start position:0% +closed bracket so I'm spawning off foo +which is the lower part there and + + align:start position:0% +which is the lower part there and + + + align:start position:0% +which is the lower part there and +locking and unlocking and up above I'm + + align:start position:0% +locking and unlocking and up above I'm + + + align:start position:0% +locking and unlocking and up above I'm +locking and unlocking so what can happen + + align:start position:0% +locking and unlocking so what can happen + + + align:start position:0% +locking and unlocking so what can happen +here I can go and I basically spawn off + + align:start position:0% +here I can go and I basically spawn off + + + align:start position:0% +here I can go and I basically spawn off +the child but then I lock and now the + + align:start position:0% +the child but then I lock and now the + + + align:start position:0% +the child but then I lock and now the +child goes and it says oh I can't you + + align:start position:0% +child goes and it says oh I can't you + + + align:start position:0% +child goes and it says oh I can't you +know foo is going to wait here because + + align:start position:0% +know foo is going to wait here because + + + align:start position:0% +know foo is going to wait here because +it can't grab the lock as it's owned by + + align:start position:0% +it can't grab the lock as it's owned by + + + align:start position:0% +it can't grab the lock as it's owned by +the by main ok and now we get to the + + align:start position:0% +the by main ok and now we get to the + + + align:start position:0% +the by main ok and now we get to the +point where main is has to wait for the + + align:start position:0% +point where main is has to wait for the + + + align:start position:0% +point where main is has to wait for the +sink okay and the child is never going + + align:start position:0% +sink okay and the child is never going + + + align:start position:0% +sink okay and the child is never going +to complete because I hold the resource + + align:start position:0% +to complete because I hold the resource + + + align:start position:0% +to complete because I hold the resource +that the child needs to complete okay so + + align:start position:0% +that the child needs to complete okay so + + + align:start position:0% +that the child needs to complete okay so +don't hold mutexes across silk sinks + + align:start position:0% +don't hold mutexes across silk sinks + + + align:start position:0% +don't hold mutexes across silk sinks +that's the lesson there there are + + align:start position:0% +that's the lesson there there are + + + align:start position:0% +that's the lesson there there are +actually places you can but if you don't + + align:start position:0% +actually places you can but if you don't + + + align:start position:0% +actually places you can but if you don't +hold them across that then you won't run + + align:start position:0% +hold them across that then you won't run + + + align:start position:0% +hold them across that then you won't run +into this particular problem a good + + align:start position:0% +into this particular problem a good + + + align:start position:0% +into this particular problem a good +strategy is only holding mutexes within + + align:start position:0% +strategy is only holding mutexes within + + + align:start position:0% +strategy is only holding mutexes within +strands okay so there's no parallelism + + align:start position:0% +strands okay so there's no parallelism + + + align:start position:0% +strands okay so there's no parallelism +so you you have it bounded and also + + align:start position:0% +so you you have it bounded and also + + + align:start position:0% +so you you have it bounded and also +that's a good idea generally because you + + align:start position:0% +that's a good idea generally because you + + + align:start position:0% +that's a good idea generally because you +want to hold mutex as a short amount of + + align:start position:0% +want to hold mutex as a short amount of + + + align:start position:0% +want to hold mutex as a short amount of +time as you possibly can + + align:start position:0% +time as you possibly can + + + align:start position:0% +time as you possibly can +so for example if you have a big + + align:start position:0% +so for example if you have a big + + + align:start position:0% +so for example if you have a big +calculation and then you want to sign + + align:start position:0% +calculation and then you want to sign + + + align:start position:0% +calculation and then you want to sign +something atomically don't put the big + + align:start position:0% +something atomically don't put the big + + + align:start position:0% +something atomically don't put the big +calculation inside the critical region + + align:start position:0% +calculation inside the critical region + + + align:start position:0% +calculation inside the critical region +move the calculation outside the + + align:start position:0% +move the calculation outside the + + + align:start position:0% +move the calculation outside the +critical region do the calculation you + + align:start position:0% +critical region do the calculation you + + + align:start position:0% +critical region do the calculation you +need to do and then acquire the locks + + align:start position:0% +need to do and then acquire the locks + + + align:start position:0% +need to do and then acquire the locks +just to do the interaction you need to + + align:start position:0% +just to do the interaction you need to + + + align:start position:0% +just to do the interaction you need to +set a value okay so that's and then + + align:start position:0% +set a value okay so that's and then + + + align:start position:0% +set a value okay so that's and then +you'll have a lot faster code okay + + align:start position:0% +you'll have a lot faster code okay + + + align:start position:0% +you'll have a lot faster code okay +because you're not holding up other + + align:start position:0% +because you're not holding up other + + + align:start position:0% +because you're not holding up other +threads for a long time and always try + + align:start position:0% +threads for a long time and always try + + + align:start position:0% +threads for a long time and always try +to avoid non-deterministic programming + + align:start position:0% +to avoid non-deterministic programming + + + align:start position:0% +to avoid non-deterministic programming +but that's not always possible okay I + + align:start position:0% +but that's not always possible okay I + + + align:start position:0% +but that's not always possible okay I +want to so any questions about that then + + align:start position:0% +want to so any questions about that then + + + align:start position:0% +want to so any questions about that then +I want to go on a really interesting + + align:start position:0% +I want to go on a really interesting + + + align:start position:0% +I want to go on a really interesting +topic because it's really + + align:start position:0% +topic because it's really + + + align:start position:0% +topic because it's really +you know recent research level topic and + + align:start position:0% +you know recent research level topic and + + + align:start position:0% +you know recent research level topic and +that's to talk about transactional + + align:start position:0% +that's to talk about transactional + + + align:start position:0% +that's to talk about transactional +memory who's heard this term before + + align:start position:0% +memory who's heard this term before + + + align:start position:0% +memory who's heard this term before +anybody okay so the idea is to have + + align:start position:0% +anybody okay so the idea is to have + + + align:start position:0% +anybody okay so the idea is to have +database transactions that you have + + align:start position:0% +database transactions that you have + + + align:start position:0% +database transactions that you have +things like database transaction or the + + align:start position:0% +things like database transaction or the + + + align:start position:0% +things like database transaction or the +atomicity is happening implicitly you + + align:start position:0% +atomicity is happening implicitly you + + + align:start position:0% +atomicity is happening implicitly you +don't specify locks you just say this is + + align:start position:0% +don't specify locks you just say this is + + + align:start position:0% +don't specify locks you just say this is +a critical region okay don't interrupt + + align:start position:0% +a critical region okay don't interrupt + + + align:start position:0% +a critical region okay don't interrupt +me while I do this critical region the + + align:start position:0% +me while I do this critical region the + + + align:start position:0% +me while I do this critical region the +system works everything out okay here's + + align:start position:0% +system works everything out okay here's + + + align:start position:0% +system works everything out okay here's +a good example of where it might be + + align:start position:0% +a good example of where it might be + + + align:start position:0% +a good example of where it might be +useful suppose we want to do a + + align:start position:0% +useful suppose we want to do a + + + align:start position:0% +useful suppose we want to do a +concurrent graph computation okay and so + + align:start position:0% +concurrent graph computation okay and so + + + align:start position:0% +concurrent graph computation okay and so +you take people involved in parallel and + + align:start position:0% +you take people involved in parallel and + + + align:start position:0% +you take people involved in parallel and +distributed computing and at MIT and you + + align:start position:0% +distributed computing and at MIT and you + + + align:start position:0% +distributed computing and at MIT and you +say okay I want to do Gaussian + + align:start position:0% +say okay I want to do Gaussian + + + align:start position:0% +say okay I want to do Gaussian +elimination on this graph now you guys + + align:start position:0% +elimination on this graph now you guys + + + align:start position:0% +elimination on this graph now you guys +are sure most of you know Gaussian + + align:start position:0% +are sure most of you know Gaussian + + + align:start position:0% +are sure most of you know Gaussian +elimination from the matrix context do + + align:start position:0% +elimination from the matrix context do + + + align:start position:0% +elimination from the matrix context do +you know what it means in a graph + + align:start position:0% +you know what it means in a graph + + + align:start position:0% +you know what it means in a graph +context so if you have a sparse matrix + + align:start position:0% +context so if you have a sparse matrix + + + align:start position:0% +context so if you have a sparse matrix +you actually have a graph and Gaussian + + align:start position:0% +you actually have a graph and Gaussian + + + align:start position:0% +you actually have a graph and Gaussian +elimination is a way of manipulating the + + align:start position:0% +elimination is a way of manipulating the + + + align:start position:0% +elimination is a way of manipulating the +graph and you get exactly the same + + align:start position:0% +graph and you get exactly the same + + + align:start position:0% +graph and you get exactly the same +behavior as you get in the dense one so + + align:start position:0% +behavior as you get in the dense one so + + + align:start position:0% +behavior as you get in the dense one so +I'll show you what it what it is you + + align:start position:0% +I'll show you what it what it is you + + + align:start position:0% +I'll show you what it what it is you +basically pick somebody to eliminate + + align:start position:0% +basically pick somebody to eliminate + + + align:start position:0% +basically pick somebody to eliminate +okay + + align:start position:0% + + + + align:start position:0% + +okay and now what you do is look at all + + align:start position:0% +okay and now what you do is look at all + + + align:start position:0% +okay and now what you do is look at all +this all the this vertexes neighbors + + align:start position:0% +this all the this vertexes neighbors + + + align:start position:0% +this all the this vertexes neighbors +okay + + align:start position:0% +okay + + + align:start position:0% +okay +those guys and what you do is you + + align:start position:0% +those guys and what you do is you + + + align:start position:0% +those guys and what you do is you +eliminate that vertex bye-bye okay + + align:start position:0% +eliminate that vertex bye-bye okay + + + align:start position:0% +eliminate that vertex bye-bye okay +and you interconnect all the neighbors + + align:start position:0% +and you interconnect all the neighbors + + + align:start position:0% +and you interconnect all the neighbors +with all the edges that don't already + + align:start position:0% +with all the edges that don't already + + + align:start position:0% +with all the edges that don't already +exist and that's Gaussian elimination if + + align:start position:0% +exist and that's Gaussian elimination if + + + align:start position:0% +exist and that's Gaussian elimination if +you think of it in terms of matrix + + align:start position:0% +you think of it in terms of matrix + + + align:start position:0% +you think of it in terms of matrix +fashion the question is if you have a + + align:start position:0% +fashion the question is if you have a + + + align:start position:0% +fashion the question is if you have a +sparse matrix where are you going to get + + align:start position:0% +sparse matrix where are you going to get + + + align:start position:0% +sparse matrix where are you going to get +fill-in what are the places that you + + align:start position:0% +fill-in what are the places that you + + + align:start position:0% +fill-in what are the places that you +need to update when you do a pivot in + + align:start position:0% +need to update when you do a pivot in + + + align:start position:0% +need to update when you do a pivot in +Gaussian elimination in a matrix okay so + + align:start position:0% +Gaussian elimination in a matrix okay so + + + align:start position:0% +Gaussian elimination in a matrix okay so +that's the basic notion of graph of + + align:start position:0% +that's the basic notion of graph of + + + align:start position:0% +that's the basic notion of graph of +doing Gaussian elimination but now we + + align:start position:0% +doing Gaussian elimination but now we + + + align:start position:0% +doing Gaussian elimination but now we +want to deal with the concurrency okay + + align:start position:0% +want to deal with the concurrency okay + + + align:start position:0% +want to deal with the concurrency okay +and the problem occurs is if I want to + + align:start position:0% +and the problem occurs is if I want to + + + align:start position:0% +and the problem occurs is if I want to +eliminate two nodes at the same time + + align:start position:0% +eliminate two nodes at the same time + + + align:start position:0% +eliminate two nodes at the same time +okay because now they're adjacent each + + align:start position:0% +okay because now they're adjacent each + + + align:start position:0% +okay because now they're adjacent each +other and if I just do what i Express + + align:start position:0% +other and if I just do what i Express + + + align:start position:0% +other and if I just do what i Express +there's going to be all kinds of + + align:start position:0% +there's going to be all kinds of + + + align:start position:0% +there's going to be all kinds of +atomicity violations etc by the way the + + align:start position:0% +atomicity violations etc by the way the + + + align:start position:0% +atomicity violations etc by the way the +reason I'm picking these two folks is + + align:start position:0% +reason I'm picking these two folks is + + + align:start position:0% +reason I'm picking these two folks is +because they're going to a better place + + align:start position:0% + + + + align:start position:0% + +okay so so how do you deal with this and + + align:start position:0% +okay so so how do you deal with this and + + + align:start position:0% +okay so so how do you deal with this and +so in transactional memory what I want + + align:start position:0% +so in transactional memory what I want + + + align:start position:0% +so in transactional memory what I want +to be able to do is just simply say okay + + align:start position:0% +to be able to do is just simply say okay + + + align:start position:0% +to be able to do is just simply say okay +here's the thing that I need to be + + align:start position:0% +here's the thing that I need to be + + + align:start position:0% +here's the thing that I need to be +atomic and so if I look at this code + + align:start position:0% +atomic and so if I look at this code + + + align:start position:0% +atomic and so if I look at this code +it's basically saying you know who are + + align:start position:0% +it's basically saying you know who are + + + align:start position:0% +it's basically saying you know who are +my neighbors and then let me identify + + align:start position:0% +my neighbors and then let me identify + + + align:start position:0% +my neighbors and then let me identify +all of the edges that need to be removed + + align:start position:0% +all of the edges that need to be removed + + + align:start position:0% +all of the edges that need to be removed +the ones that I just showed you they + + align:start position:0% +the ones that I just showed you they + + + align:start position:0% +the ones that I just showed you they +know that we're moved now let me get rid + + align:start position:0% +know that we're moved now let me get rid + + + align:start position:0% +know that we're moved now let me get rid +of the element you know V and now for + + align:start position:0% +of the element you know V and now for + + + align:start position:0% +of the element you know V and now for +all of the neighbors of U let us let us + + align:start position:0% +all of the neighbors of U let us let us + + + align:start position:0% +all of the neighbors of U let us let us +add in the edge between the neighbor and + + align:start position:0% +add in the edge between the neighbor and + + + align:start position:0% +add in the edge between the neighbor and +you know between the pairs of neighbors + + align:start position:0% +you know between the pairs of neighbors + + + align:start position:0% +you know between the pairs of neighbors +okay so that's basically what it's doing + + align:start position:0% +okay so that's basically what it's doing + + + align:start position:0% +okay so that's basically what it's doing +okay and I'd like to just say that's + + align:start position:0% +okay and I'd like to just say that's + + + align:start position:0% +okay and I'd like to just say that's +atomic okay and so the idea is that if I + + align:start position:0% +atomic okay and so the idea is that if I + + + align:start position:0% +atomic okay and so the idea is that if I +express that as a transaction then the + + align:start position:0% +express that as a transaction then the + + + align:start position:0% +express that as a transaction then the +ID + + align:start position:0% +ID + + + align:start position:0% +ID +is that on the transaction commit all + + align:start position:0% +is that on the transaction commit all + + + align:start position:0% +is that on the transaction commit all +the memory updates in the critical + + align:start position:0% +the memory updates in the critical + + + align:start position:0% +the memory updates in the critical +region appear to take it happen at once + + align:start position:0% +region appear to take it happen at once + + + align:start position:0% +region appear to take it happen at once +however in transaction member the idea + + align:start position:0% +however in transaction member the idea + + + align:start position:0% +however in transaction member the idea +is rather than forcing it go forward I + + align:start position:0% +is rather than forcing it go forward I + + + align:start position:0% +is rather than forcing it go forward I +can have the transactions abort okay so + + align:start position:0% +can have the transactions abort okay so + + + align:start position:0% +can have the transactions abort okay so +if I get a conflict I'll abort one and + + align:start position:0% +if I get a conflict I'll abort one and + + + align:start position:0% +if I get a conflict I'll abort one and +restart it and then the restarted + + align:start position:0% +restart it and then the restarted + + + align:start position:0% +restart it and then the restarted +transaction may take a different code + + align:start position:0% +transaction may take a different code + + + align:start position:0% +transaction may take a different code +path because after all I may have + + align:start position:0% +path because after all I may have + + + align:start position:0% +path because after all I may have +restructured the graph underneath and so + + align:start position:0% +restructured the graph underneath and so + + + align:start position:0% +restructured the graph underneath and so +it's may do something different the + + align:start position:0% +it's may do something different the + + + align:start position:0% +it's may do something different the +second time through the first it may + + align:start position:0% +second time through the first it may + + + align:start position:0% +second time through the first it may +also abort again and so forth so when + + align:start position:0% +also abort again and so forth so when + + + align:start position:0% +also abort again and so forth so when +you study transaction transactional + + align:start position:0% +you study transaction transactional + + + align:start position:0% +you study transaction transactional +memory let me just do a couple of - + + align:start position:0% +memory let me just do a couple of - + + + align:start position:0% +memory let me just do a couple of - +there's one is a conflict that's when + + align:start position:0% +there's one is a conflict that's when + + + align:start position:0% +there's one is a conflict that's when +you have two transactions that are you + + align:start position:0% +you have two transactions that are you + + + align:start position:0% +you have two transactions that are you +know they can't both complete one of + + align:start position:0% +know they can't both complete one of + + + align:start position:0% +know they can't both complete one of +them has to be aborted okay and aborting + + align:start position:0% +them has to be aborted okay and aborting + + + align:start position:0% +them has to be aborted okay and aborting +by the way is once again violating the + + align:start position:0% +by the way is once again violating the + + + align:start position:0% +by the way is once again violating the +non you know you know the non + + align:start position:0% +non you know you know the non + + + align:start position:0% +non you know you know the non +pre-emptive nature here we're going to + + align:start position:0% +pre-emptive nature here we're going to + + + align:start position:0% +pre-emptive nature here we're going to +preempt one of them by by keeping all + + align:start position:0% +preempt one of them by by keeping all + + + align:start position:0% +preempt one of them by by keeping all +the states so I can roll a state back + + align:start position:0% +the states so I can roll a state back + + + align:start position:0% +the states so I can roll a state back +and restart it from scratch so + + align:start position:0% +and restart it from scratch so + + + align:start position:0% +and restart it from scratch so +contention resolution is deciding which + + align:start position:0% +contention resolution is deciding which + + + align:start position:0% +contention resolution is deciding which +of the two conflicting transit actions + + align:start position:0% +of the two conflicting transit actions + + + align:start position:0% +of the two conflicting transit actions +to wait or to abort and restart and + + align:start position:0% +to wait or to abort and restart and + + + align:start position:0% +to wait or to abort and restart and +under what conditions you do that so the + + align:start position:0% +under what conditions you do that so the + + + align:start position:0% +under what conditions you do that so the +resolution manager has to figure out + + align:start position:0% +resolution manager has to figure out + + + align:start position:0% +resolution manager has to figure out +what happens in the case of contention + + align:start position:0% +what happens in the case of contention + + + align:start position:0% +what happens in the case of contention +and then forward progress is avoiding + + align:start position:0% +and then forward progress is avoiding + + + align:start position:0% +and then forward progress is avoiding +deadlock of course but also livelock and + + align:start position:0% +deadlock of course but also livelock and + + + align:start position:0% +deadlock of course but also livelock and +starvation you want to make sure that + + align:start position:0% +starvation you want to make sure that + + + align:start position:0% +starvation you want to make sure that +you're going to make because what you + + align:start position:0% +you're going to make because what you + + + align:start position:0% +you're going to make because what you +don't want to have happen for example is + + align:start position:0% +don't want to have happen for example is + + + align:start position:0% +don't want to have happen for example is +that two transactions keep aborting each + + align:start position:0% +that two transactions keep aborting each + + + align:start position:0% +that two transactions keep aborting each +other and you never make forward + + align:start position:0% +other and you never make forward + + + align:start position:0% +other and you never make forward +progress and throughput well you'd like + + align:start position:0% +progress and throughput well you'd like + + + align:start position:0% +progress and throughput well you'd like +to run as many transactions as + + align:start position:0% +to run as many transactions as + + + align:start position:0% +to run as many transactions as +concurrently as possible so I'm going to + + align:start position:0% +concurrently as possible so I'm going to + + + align:start position:0% +concurrently as possible so I'm going to +show you an algorithm for doing this + + align:start position:0% +show you an algorithm for doing this + + + align:start position:0% +show you an algorithm for doing this +it's a really simple algorithm okay it + + align:start position:0% +it's a really simple algorithm okay it + + + align:start position:0% +it's a really simple algorithm okay it +happens to be one that I discovered just + + align:start position:0% +happens to be one that I discovered just + + + align:start position:0% +happens to be one that I discovered just +a couple of years ago okay and I was + + align:start position:0% +a couple of years ago okay and I was + + + align:start position:0% +a couple of years ago okay and I was +surprised that it did not appear in the + + align:start position:0% +surprised that it did not appear in the + + + align:start position:0% +surprised that it did not appear in the +literature and so I wrote a very short + + align:start position:0% +literature and so I wrote a very short + + + align:start position:0% +literature and so I wrote a very short +paper on it because it's because what + + align:start position:0% +paper on it because it's because what + + + align:start position:0% +paper on it because it's because what +happens for a lot of people is they you + + align:start position:0% +happens for a lot of people is they you + + + align:start position:0% +happens for a lot of people is they you +know in if they discover there's a lot + + align:start position:0% +know in if they discover there's a lot + + + align:start position:0% +know in if they discover there's a lot +of aborting they say oh well let's grab + + align:start position:0% +of aborting they say oh well let's grab + + + align:start position:0% +of aborting they say oh well let's grab +a global lock + + align:start position:0% +a global lock + + + align:start position:0% +a global lock +and then if everybody grabs a global + + align:start position:0% +and then if everybody grabs a global + + + align:start position:0% +and then if everybody grabs a global +lock you can do this sort of thing you + + align:start position:0% +lock you can do this sort of thing you + + + align:start position:0% +lock you can do this sort of thing you +can't deadlock with a single lock if if + + align:start position:0% +can't deadlock with a single lock if if + + + align:start position:0% +can't deadlock with a single lock if if +you're not also doing things like you + + align:start position:0% +you're not also doing things like you + + + align:start position:0% +you're not also doing things like you +know silk sync or whatever but but in + + align:start position:0% +know silk sync or whatever but but in + + + align:start position:0% +know silk sync or whatever but but in +any case if you have just a single lock + + align:start position:0% +any case if you have just a single lock + + + align:start position:0% +any case if you have just a single lock +everybody falls back to the single lock + + align:start position:0% +everybody falls back to the single lock + + + align:start position:0% +everybody falls back to the single lock +and then you have no concurrency in your + + align:start position:0% +and then you have no concurrency in your + + + align:start position:0% +and then you have no concurrency in your +program no performance until everybody + + align:start position:0% +program no performance until everybody + + + align:start position:0% +program no performance until everybody +gets through the difficult time so this + + align:start position:0% +gets through the difficult time so this + + + align:start position:0% +gets through the difficult time so this +is an algorithm that doesn't require a + + align:start position:0% +is an algorithm that doesn't require a + + + align:start position:0% +is an algorithm that doesn't require a +global lock okay so it assumes that + + align:start position:0% +global lock okay so it assumes that + + + align:start position:0% +global lock okay so it assumes that +transactional memory system will log the + + align:start position:0% +transactional memory system will log the + + + align:start position:0% +transactional memory system will log the +reads and writes that's typically true + + align:start position:0% +reads and writes that's typically true + + + align:start position:0% +reads and writes that's typically true +of any transaction maybe you log what + + align:start position:0% +of any transaction maybe you log what + + + align:start position:0% +of any transaction maybe you log what +reads and writes you're doing so that + + align:start position:0% +reads and writes you're doing so that + + + align:start position:0% +reads and writes you're doing so that +you can either abort and rollback or you + + align:start position:0% +you can either abort and rollback or you + + + align:start position:0% +you can either abort and rollback or you +can when you abort you or else you + + align:start position:0% +can when you abort you or else you + + + align:start position:0% +can when you abort you or else you +sandbox things and then atomically + + align:start position:0% +sandbox things and then atomically + + + align:start position:0% +sandbox things and then atomically +commit them okay and so we have all the + + align:start position:0% +commit them okay and so we have all the + + + align:start position:0% +commit them okay and so we have all the +mechanisms for boarding and rolling back + + align:start position:0% +mechanisms for boarding and rolling back + + + align:start position:0% +mechanisms for boarding and rolling back +these are all very interesting in their + + align:start position:0% +these are all very interesting in their + + + align:start position:0% +these are all very interesting in their +own right and restarting and this is + + align:start position:0% +own right and restarting and this is + + + align:start position:0% +own right and restarting and this is +going to basically use a lock based + + align:start position:0% +going to basically use a lock based + + + align:start position:0% +going to basically use a lock based +approach that uses two ideas one is the + + align:start position:0% +approach that uses two ideas one is the + + + align:start position:0% +approach that uses two ideas one is the +notion of what's called a final finite + + align:start position:0% +notion of what's called a final finite + + + align:start position:0% +notion of what's called a final finite +ownership array and then another is a + + align:start position:0% +ownership array and then another is a + + + align:start position:0% +ownership array and then another is a +thing called release sort require and + + align:start position:0% +thing called release sort require and + + + align:start position:0% +thing called release sort require and +let me explain those two things and I'll + + align:start position:0% +let me explain those two things and I'll + + + align:start position:0% +let me explain those two things and I'll +show you really quickly how this + + align:start position:0% +show you really quickly how this + + + align:start position:0% +show you really quickly how this +beautiful algorithm works okay so you + + align:start position:0% +beautiful algorithm works okay so you + + + align:start position:0% +beautiful algorithm works okay so you +have an array of anti starvation mutual + + align:start position:0% +have an array of anti starvation mutual + + + align:start position:0% +have an array of anti starvation mutual +exclusion locks so these are ones that + + align:start position:0% +exclusion locks so these are ones that + + + align:start position:0% +exclusion locks so these are ones that +are going to be fair okay so that so + + align:start position:0% +are going to be fair okay so that so + + + align:start position:0% +are going to be fair okay so that so +that you're always going for the oldest + + align:start position:0% +that you're always going for the oldest + + + align:start position:0% +that you're always going for the oldest +one and you can do in a acquire we're + + align:start position:0% +one and you can do in a acquire we're + + + align:start position:0% +one and you can do in a acquire we're +also going to add in a try acquire tell + + align:start position:0% +also going to add in a try acquire tell + + + align:start position:0% +also going to add in a try acquire tell +me whether if I tried to acquire I would + + align:start position:0% +me whether if I tried to acquire I would + + + align:start position:0% +me whether if I tried to acquire I would +get it that is megive it to me if I + + align:start position:0% +get it that is megive it to me if I + + + align:start position:0% +get it that is megive it to me if I +don't get it + + align:start position:0% +don't get it + + + align:start position:0% +don't get it +don't wait just tell me that I didn't + + align:start position:0% +don't wait just tell me that I didn't + + + align:start position:0% +don't wait just tell me that I didn't +get it okay and then release and there's + + align:start position:0% +get it okay and then release and there's + + + align:start position:0% +get it okay and then release and there's +an owner function that map's + + align:start position:0% +an owner function that map's + + + align:start position:0% +an owner function that map's +all of the function H that map's my + + align:start position:0% +all of the function H that map's my + + + align:start position:0% +all of the function H that map's my +universe of memory locations to the + + align:start position:0% +universe of memory locations to the + + + align:start position:0% +universe of memory locations to the +indexes in this finite ownership array + + align:start position:0% +indexes in this finite ownership array + + + align:start position:0% +indexes in this finite ownership array +this lock array okay so the lock has + + align:start position:0% +this lock array okay so the lock has + + + align:start position:0% +this lock array okay so the lock has +length array has length n has n slots in + + align:start position:0% +length array has length n has n slots in + + + align:start position:0% +length array has length n has n slots in +it to lock a location X in the set of + + align:start position:0% +it to lock a location X in the set of + + + align:start position:0% +it to lock a location X in the set of +all possible + + align:start position:0% +all possible + + + align:start position:0% +all possible +you actually require lock of H of X so + + align:start position:0% +you actually require lock of H of X so + + + align:start position:0% +you actually require lock of H of X so +you can think of H as a hash function + + align:start position:0% +you can think of H as a hash function + + + align:start position:0% +you can think of H as a hash function +but doesn't have to be a fair hash + + align:start position:0% +but doesn't have to be a fair hash + + + align:start position:0% +but doesn't have to be a fair hash +function or whatever any function will + + align:start position:0% +function or whatever any function will + + + align:start position:0% +function or whatever any function will +do okay and then there yes there'll be + + align:start position:0% +do okay and then there yes there'll be + + + align:start position:0% +do okay and then there yes there'll be +some advantages to picking some + + align:start position:0% +some advantages to picking some + + + align:start position:0% +some advantages to picking some +functions or another one okay so in + + align:start position:0% +functions or another one okay so in + + + align:start position:0% +functions or another one okay so in +rather than actually locking the + + align:start position:0% +rather than actually locking the + + + align:start position:0% +rather than actually locking the +location or locking the object I lock a + + align:start position:0% +location or locking the object I lock a + + + align:start position:0% +location or locking the object I lock a +location that I that essentially I hash + + align:start position:0% +location that I that essentially I hash + + + align:start position:0% +location that I that essentially I hash +to from that object so if two guys are + + align:start position:0% +to from that object so if two guys are + + + align:start position:0% +to from that object so if two guys are +trying to grab the same location they + + align:start position:0% +trying to grab the same location they + + + align:start position:0% +trying to grab the same location they +will both grab the same lock because + + align:start position:0% +will both grab the same lock because + + + align:start position:0% +will both grab the same lock because +they've got the same hash function but I + + align:start position:0% +they've got the same hash function but I + + + align:start position:0% +they've got the same hash function but I +may have inadvertently where if I were + + align:start position:0% +may have inadvertently where if I were + + + align:start position:0% +may have inadvertently where if I were +locking the objects themselves okay I + + align:start position:0% +locking the objects themselves okay I + + + align:start position:0% +locking the objects themselves okay I +wouldn't have them both trying to + + align:start position:0% +wouldn't have them both trying to + + + align:start position:0% +wouldn't have them both trying to +acquire the same lock that might happen + + align:start position:0% +acquire the same lock that might happen + + + align:start position:0% +acquire the same lock that might happen +in this algorithm okay so here's the + + align:start position:0% +in this algorithm okay so here's the + + + align:start position:0% +in this algorithm okay so here's the +idea it's called the first idea is + + align:start position:0% +idea it's called the first idea is + + + align:start position:0% +idea it's called the first idea is +called a release sort and reacquires so + + align:start position:0% +called a release sort and reacquires so + + + align:start position:0% +called a release sort and reacquires so +that's the ownership array part that I + + align:start position:0% +that's the ownership array part that I + + + align:start position:0% +that's the ownership array part that I +just explained now here's the release + + align:start position:0% +just explained now here's the release + + + align:start position:0% +just explained now here's the release +sort a quat reacquire before you access + + align:start position:0% +sort a quat reacquire before you access + + + align:start position:0% +sort a quat reacquire before you access +a memory location X simply try to grab + + align:start position:0% +a memory location X simply try to grab + + + align:start position:0% +a memory location X simply try to grab +lock of X greedily and if you if you + + align:start position:0% +lock of X greedily and if you if you + + + align:start position:0% +lock of X greedily and if you if you +have a conflict okay so if you don't + + align:start position:0% +have a conflict okay so if you don't + + + align:start position:0% +have a conflict okay so if you don't +have a conflict you get it you just + + align:start position:0% +have a conflict you get it you just + + + align:start position:0% +have a conflict you get it you just +simply try to get it if you can that's + + align:start position:0% +simply try to get it if you can that's + + + align:start position:0% +simply try to get it if you can that's +great if not then what I'm going to do + + align:start position:0% +great if not then what I'm going to do + + + align:start position:0% +great if not then what I'm going to do +is roll back the transaction but don't + + align:start position:0% +is roll back the transaction but don't + + + align:start position:0% +is roll back the transaction but don't +release the locks I hold and then + + align:start position:0% +release the locks I hold and then + + + align:start position:0% +release the locks I hold and then +release all the locks with index is + + align:start position:0% +release all the locks with index is + + + align:start position:0% +release all the locks with index is +greater than H of X and then I'm gonna + + align:start position:0% +greater than H of X and then I'm gonna + + + align:start position:0% +greater than H of X and then I'm gonna +choir the lock that I want and now at + + align:start position:0% +choir the lock that I want and now at + + + align:start position:0% +choir the lock that I want and now at +that point I've released all the bigger + + align:start position:0% +that point I've released all the bigger + + + align:start position:0% +that point I've released all the bigger +locks so I'm acquiring the next lock and + + align:start position:0% +locks so I'm acquiring the next lock and + + + align:start position:0% +locks so I'm acquiring the next lock and +then I acquire the released locks in + + align:start position:0% +then I acquire the released locks in + + + align:start position:0% +then I acquire the released locks in +sorted order so I go through all the + + align:start position:0% +sorted order so I go through all the + + + align:start position:0% +sorted order so I go through all the +locks I release and I really min sorted + + align:start position:0% +locks I release and I really min sorted + + + align:start position:0% +locks I release and I really min sorted +order okay and then I start my + + align:start position:0% +order okay and then I start my + + + align:start position:0% +order okay and then I start my +transaction over again I try again so + + align:start position:0% +transaction over again I try again so + + + align:start position:0% +transaction over again I try again so +what happens each time through this + + align:start position:0% +what happens each time through this + + + align:start position:0% +what happens each time through this +process + + align:start position:0% +process + + + align:start position:0% +process +I'm always whenever trying to acquire a + + align:start position:0% +I'm always whenever trying to acquire a + + + align:start position:0% +I'm always whenever trying to acquire a +lock I'm only holding locks that are + + align:start position:0% +lock I'm only holding locks that are + + + align:start position:0% +lock I'm only holding locks that are +smaller but each time that I restart I + + align:start position:0% +smaller but each time that I restart I + + + align:start position:0% +smaller but each time that I restart I +have one more lock that I didn't used to + + align:start position:0% +have one more lock that I didn't used to + + + align:start position:0% +have one more lock that I didn't used to +have before I restart my transaction + + align:start position:0% +have before I restart my transaction + + + align:start position:0% +have before I restart my transaction +which I've acquired in the order in the + + align:start position:0% +which I've acquired in the order in the + + + align:start position:0% +which I've acquired in the order in the +linear order from you know from the + + align:start position:0% +linear order from you know from the + + + align:start position:0% +linear order from you know from the +in that ownership array from zero to n + + align:start position:0% +in that ownership array from zero to n + + + align:start position:0% +in that ownership array from zero to n +minus one okay and so here's the + + align:start position:0% +minus one okay and so here's the + + + align:start position:0% +minus one okay and so here's the +algorithm I'll let you guys look at it + + align:start position:0% +algorithm I'll let you guys look at it + + + align:start position:0% +algorithm I'll let you guys look at it +in more detail because I see our our + + align:start position:0% +in more detail because I see our our + + + align:start position:0% +in more detail because I see our our +time is up and it's actually fun to take + + align:start position:0% +time is up and it's actually fun to take + + + align:start position:0% +time is up and it's actually fun to take +a look at and we'll put the paper online + + align:start position:0% +a look at and we'll put the paper online + + + align:start position:0% +a look at and we'll put the paper online +there's one other topic that I wanted to + + align:start position:0% +there's one other topic that I wanted to + + + align:start position:0% +there's one other topic that I wanted to +go through here which is which you + + align:start position:0% +go through here which is which you + + + align:start position:0% +go through here which is which you +should know about is this locking + + align:start position:0% +should know about is this locking + + + align:start position:0% +should know about is this locking +anomaly called convoying and this was + + align:start position:0% +anomaly called convoying and this was + + + align:start position:0% +anomaly called convoying and this was +actually a bug that we had performance + + align:start position:0% +actually a bug that we had performance + + + align:start position:0% +actually a bug that we had performance +bug that we had in our original MIT silk + + align:start position:0% +bug that we had in our original MIT silk + + + align:start position:0% +bug that we had in our original MIT silk +so it's kind of a neat one to see and + + align:start position:0% +so it's kind of a neat one to see and + + + align:start position:0% +so it's kind of a neat one to see and +how we resolved it and that's it \ No newline at end of file diff --git a/mwL__eKs3fI.txt b/mwL__eKs3fI.txt new file mode 100644 index 0000000000000000000000000000000000000000..82c555e44424139ccc67956a538d232f3a69a528 --- /dev/null +++ b/mwL__eKs3fI.txt @@ -0,0 +1,947 @@ +align:start position:0% + +devious video we used data in linear + + align:start position:0% +devious video we used data in linear + + + align:start position:0% +devious video we used data in linear +regression to show that if a team scores + + align:start position:0% +regression to show that if a team scores + + + align:start position:0% +regression to show that if a team scores +at least 135 more runs than their + + align:start position:0% +at least 135 more runs than their + + + align:start position:0% +at least 135 more runs than their +opponent throughout the regular season + + align:start position:0% +opponent throughout the regular season + + + align:start position:0% +opponent throughout the regular season +then we predict that that team will win + + align:start position:0% +then we predict that that team will win + + + align:start position:0% +then we predict that that team will win +at least 95 games and make the playoffs + + align:start position:0% +at least 95 games and make the playoffs + + + align:start position:0% +at least 95 games and make the playoffs +this means that we need to know how many + + align:start position:0% +this means that we need to know how many + + + align:start position:0% +this means that we need to know how many +runs a team will score which we will + + align:start position:0% +runs a team will score which we will + + + align:start position:0% +runs a team will score which we will +show can be predicted using batting + + align:start position:0% +show can be predicted using batting + + + align:start position:0% +show can be predicted using batting +statistics and how many runs a team will + + align:start position:0% +statistics and how many runs a team will + + + align:start position:0% +statistics and how many runs a team will +allow which we will show can be + + align:start position:0% +allow which we will show can be + + + align:start position:0% +allow which we will show can be +predicted using fielding and pitching + + align:start position:0% +predicted using fielding and pitching + + + align:start position:0% +predicted using fielding and pitching +statistics let's start by creating a + + align:start position:0% +statistics let's start by creating a + + + align:start position:0% +statistics let's start by creating a +linear regression model to predict run + + align:start position:0% +linear regression model to predict run + + + align:start position:0% +linear regression model to predict run +scored the Oakland A's are interested in + + align:start position:0% +scored the Oakland A's are interested in + + + align:start position:0% +scored the Oakland A's are interested in +answering the question how does a team + + align:start position:0% +answering the question how does a team + + + align:start position:0% +answering the question how does a team +score more runs they discovered that two + + align:start position:0% +score more runs they discovered that two + + + align:start position:0% +score more runs they discovered that two +baseball statistics were significantly + + align:start position:0% +baseball statistics were significantly + + + align:start position:0% +baseball statistics were significantly +more important than anything else + + align:start position:0% +more important than anything else + + + align:start position:0% +more important than anything else +these were on-base percentage or OBP + + align:start position:0% +these were on-base percentage or OBP + + + align:start position:0% +these were on-base percentage or OBP +which is the percentage of time a player + + align:start position:0% +which is the percentage of time a player + + + align:start position:0% +which is the percentage of time a player +gets on base including walks and + + align:start position:0% +gets on base including walks and + + + align:start position:0% +gets on base including walks and +slugging percentage or SLG which + + align:start position:0% +slugging percentage or SLG which + + + align:start position:0% +slugging percentage or SLG which +measures how far a player gets around + + align:start position:0% +measures how far a player gets around + + + align:start position:0% +measures how far a player gets around +the bases on his turn and measures the + + align:start position:0% +the bases on his turn and measures the + + + align:start position:0% +the bases on his turn and measures the +power of a hitter most teams and people + + align:start position:0% +power of a hitter most teams and people + + + align:start position:0% +power of a hitter most teams and people +in baseball focused instead on batting + + align:start position:0% +in baseball focused instead on batting + + + align:start position:0% +in baseball focused instead on batting +average or ba which measures how often a + + align:start position:0% +average or ba which measures how often a + + + align:start position:0% +average or ba which measures how often a +hitter gets on base by hitting the ball + + align:start position:0% +hitter gets on base by hitting the ball + + + align:start position:0% +hitter gets on base by hitting the ball +this focuses on hits instead of walks + + align:start position:0% +this focuses on hits instead of walks + + + align:start position:0% +this focuses on hits instead of walks +the Oakland A's claimed that on-base + + align:start position:0% +the Oakland A's claimed that on-base + + + align:start position:0% +the Oakland A's claimed that on-base +percentage was the most important + + align:start position:0% +percentage was the most important + + + align:start position:0% +percentage was the most important +slugging percentage was important and + + align:start position:0% +slugging percentage was important and + + + align:start position:0% +slugging percentage was important and +batting average was overvalued let's see + + align:start position:0% +batting average was overvalued let's see + + + align:start position:0% +batting average was overvalued let's see +if we can use linear regression in our + + align:start position:0% +if we can use linear regression in our + + + align:start position:0% +if we can use linear regression in our +to verify which baseball statistics are + + align:start position:0% +to verify which baseball statistics are + + + align:start position:0% +to verify which baseball statistics are +more important to predict runs in the + + align:start position:0% +more important to predict runs in the + + + align:start position:0% +more important to predict runs in the +previous video we created our data set + + align:start position:0% +previous video we created our data set + + + align:start position:0% +previous video we created our data set +in our and called it Moneyball let's + + align:start position:0% +in our and called it Moneyball let's + + + align:start position:0% +in our and called it Moneyball let's +take a look at the structure of our data + + align:start position:0% +take a look at the structure of our data + + + align:start position:0% +take a look at the structure of our data +again our dataset includes many + + align:start position:0% +again our dataset includes many + + + align:start position:0% +again our dataset includes many +variables including run scored or RS + + align:start position:0% +variables including run scored or RS + + + align:start position:0% +variables including run scored or RS +on-base percentage OBP slugging + + align:start position:0% +on-base percentage OBP slugging + + + align:start position:0% +on-base percentage OBP slugging +percentage SLG and batting average ba we + + align:start position:0% +percentage SLG and batting average ba we + + + align:start position:0% +percentage SLG and batting average ba we +want to see if we can use linear + + align:start position:0% +want to see if we can use linear + + + align:start position:0% +want to see if we can use linear +regression to predict run scored using + + align:start position:0% +regression to predict run scored using + + + align:start position:0% +regression to predict run scored using +the three hitting statistics on-base + + align:start position:0% +the three hitting statistics on-base + + + align:start position:0% +the three hitting statistics on-base +percentage slugging percentage and + + align:start position:0% +percentage slugging percentage and + + + align:start position:0% +percentage slugging percentage and +batting average so let's build a linear + + align:start position:0% +batting average so let's build a linear + + + align:start position:0% +batting average so let's build a linear +regression equation using the LM + + align:start position:0% +regression equation using the LM + + + align:start position:0% +regression equation using the LM +function to predict run scored using the + + align:start position:0% +function to predict run scored using the + + + align:start position:0% +function to predict run scored using the +independent variables OBP s LG mba our + + align:start position:0% +independent variables OBP s LG mba our + + + align:start position:0% +independent variables OBP s LG mba our +data set is Moneyball if we look at the + + align:start position:0% +data set is Moneyball if we look at the + + + align:start position:0% +data set is Moneyball if we look at the +summary of our regression equation we + + align:start position:0% +summary of our regression equation we + + + align:start position:0% +summary of our regression equation we +can see that all of our independent + + align:start position:0% +can see that all of our independent + + + align:start position:0% +can see that all of our independent +variables are highly significant and our + + align:start position:0% +variables are highly significant and our + + + align:start position:0% +variables are highly significant and our +r-squared is 0.93 if we look at our + + align:start position:0% +r-squared is 0.93 if we look at our + + + align:start position:0% +r-squared is 0.93 if we look at our +coefficients we see that the coefficient + + align:start position:0% +coefficients we see that the coefficient + + + align:start position:0% +coefficients we see that the coefficient +for batting average is negative this + + align:start position:0% +for batting average is negative this + + + align:start position:0% +for batting average is negative this +says that all other things being equal a + + align:start position:0% +says that all other things being equal a + + + align:start position:0% +says that all other things being equal a +team with a higher batting average will + + align:start position:0% +team with a higher batting average will + + + align:start position:0% +team with a higher batting average will +score fewer runs but this is a bit + + align:start position:0% +score fewer runs but this is a bit + + + align:start position:0% +score fewer runs but this is a bit +counterintuitive what's going on here is + + align:start position:0% +counterintuitive what's going on here is + + + align:start position:0% +counterintuitive what's going on here is +a case of multicollinearity these three + + align:start position:0% +a case of multicollinearity these three + + + align:start position:0% +a case of multicollinearity these three +hitting statistics are highly correlated + + align:start position:0% +hitting statistics are highly correlated + + + align:start position:0% +hitting statistics are highly correlated +so it's hard to interpret our model + + align:start position:0% +so it's hard to interpret our model + + + align:start position:0% +so it's hard to interpret our model +let's see if we can remove batting + + align:start position:0% +let's see if we can remove batting + + + align:start position:0% +let's see if we can remove batting +average the variable with the negative + + align:start position:0% +average the variable with the negative + + + align:start position:0% +average the variable with the negative +coefficient and the least significance + + align:start position:0% +coefficient and the least significance + + + align:start position:0% +coefficient and the least significance +to see if we can improve the interpret + + align:start position:0% +to see if we can improve the interpret + + + align:start position:0% +to see if we can improve the interpret +ability of our model so let's rerun our + + align:start position:0% +ability of our model so let's rerun our + + + align:start position:0% +ability of our model so let's rerun our +regression equation without the variable + + align:start position:0% +regression equation without the variable + + + align:start position:0% +regression equation without the variable +ba if we look at the summary of our new + + align:start position:0% +ba if we look at the summary of our new + + + align:start position:0% +ba if we look at the summary of our new +regression equation we can see that our + + align:start position:0% +regression equation we can see that our + + + align:start position:0% +regression equation we can see that our +variables are again highly significant + + align:start position:0% +variables are again highly significant + + + align:start position:0% +variables are again highly significant +the coefficients are all positive as we + + align:start position:0% +the coefficients are all positive as we + + + align:start position:0% +the coefficients are all positive as we +would expect them to be and our R + + align:start position:0% +would expect them to be and our R + + + align:start position:0% +would expect them to be and our R +squared is now 0.92 96 or about the same + + align:start position:0% +squared is now 0.92 96 or about the same + + + align:start position:0% +squared is now 0.92 96 or about the same +as before so this model is simpler with + + align:start position:0% +as before so this model is simpler with + + + align:start position:0% +as before so this model is simpler with +one fewer variable but has about the + + align:start position:0% +one fewer variable but has about the + + + align:start position:0% +one fewer variable but has about the +same predictive ability as a three + + align:start position:0% +same predictive ability as a three + + + align:start position:0% +same predictive ability as a three +variable model you can experiment and + + align:start position:0% +variable model you can experiment and + + + align:start position:0% +variable model you can experiment and +see that if we had taken out on base + + align:start position:0% +see that if we had taken out on base + + + align:start position:0% +see that if we had taken out on base +percentage or slugging percentage + + align:start position:0% +percentage or slugging percentage + + + align:start position:0% +percentage or slugging percentage +instead of batting average our r-squared + + align:start position:0% +instead of batting average our r-squared + + + align:start position:0% +instead of batting average our r-squared +would have gone down more if we look at + + align:start position:0% +would have gone down more if we look at + + + align:start position:0% +would have gone down more if we look at +the coefficients we can see that the + + align:start position:0% +the coefficients we can see that the + + + align:start position:0% +the coefficients we can see that the +coefficient for on-base percentage is + + align:start position:0% +coefficient for on-base percentage is + + + align:start position:0% +coefficient for on-base percentage is +significantly higher than the + + align:start position:0% +significantly higher than the + + + align:start position:0% +significantly higher than the +coefficient for slugging percentage + + align:start position:0% +coefficient for slugging percentage + + + align:start position:0% +coefficient for slugging percentage +since these variables are on + + align:start position:0% +since these variables are on + + + align:start position:0% +since these variables are on +the same scale this tells us that + + align:start position:0% +the same scale this tells us that + + + align:start position:0% +the same scale this tells us that +on-base percentage is worth more than + + align:start position:0% +on-base percentage is worth more than + + + align:start position:0% +on-base percentage is worth more than +slugging percentage + + align:start position:0% +slugging percentage + + + align:start position:0% +slugging percentage +so using linear regression we're able to + + align:start position:0% +so using linear regression we're able to + + + align:start position:0% +so using linear regression we're able to +verify the claims made in Moneyball that + + align:start position:0% +verify the claims made in Moneyball that + + + align:start position:0% +verify the claims made in Moneyball that +batting average is overvalued on-base + + align:start position:0% +batting average is overvalued on-base + + + align:start position:0% +batting average is overvalued on-base +percentage is the most important and + + align:start position:0% +percentage is the most important and + + + align:start position:0% +percentage is the most important and +slugging percentage is important we can + + align:start position:0% +slugging percentage is important we can + + + align:start position:0% +slugging percentage is important we can +create a very similar model to predict + + align:start position:0% +create a very similar model to predict + + + align:start position:0% +create a very similar model to predict +runs Allowed or opponent runs this model + + align:start position:0% +runs Allowed or opponent runs this model + + + align:start position:0% +runs Allowed or opponent runs this model +uses pitching statistics opponent's + + align:start position:0% +uses pitching statistics opponent's + + + align:start position:0% +uses pitching statistics opponent's +on-base percentage or oo BP an opponent + + align:start position:0% +on-base percentage or oo BP an opponent + + + align:start position:0% +on-base percentage or oo BP an opponent +slugging percentage or o SLG these + + align:start position:0% +slugging percentage or o SLG these + + + align:start position:0% +slugging percentage or o SLG these +statistics are computed in the same way + + align:start position:0% +statistics are computed in the same way + + + align:start position:0% +statistics are computed in the same way +as on-base percentage and slugging + + align:start position:0% +as on-base percentage and slugging + + + align:start position:0% +as on-base percentage and slugging +percentage but use the actions of the + + align:start position:0% +percentage but use the actions of the + + + align:start position:0% +percentage but use the actions of the +opposing batters against our team's + + align:start position:0% +opposing batters against our team's + + + align:start position:0% +opposing batters against our team's +pitcher and fielders using our data set + + align:start position:0% +pitcher and fielders using our data set + + + align:start position:0% +pitcher and fielders using our data set +in our we can build a linear regression + + align:start position:0% +in our we can build a linear regression + + + align:start position:0% +in our we can build a linear regression +model to predict runs Allowed using + + align:start position:0% +model to predict runs Allowed using + + + align:start position:0% +model to predict runs Allowed using +opponent's on-base percentage an + + align:start position:0% +opponent's on-base percentage an + + + align:start position:0% +opponent's on-base percentage an +opponent slugging percentage this is + + align:start position:0% +opponent slugging percentage this is + + + align:start position:0% +opponent slugging percentage this is +again a very strong model with an + + align:start position:0% +again a very strong model with an + + + align:start position:0% +again a very strong model with an +r-squared value of 0.9 won and both + + align:start position:0% +r-squared value of 0.9 won and both + + + align:start position:0% +r-squared value of 0.9 won and both +variables are significant in the next + + align:start position:0% +variables are significant in the next + + + align:start position:0% +variables are significant in the next +video we'll show how we can apply these + + align:start position:0% +video we'll show how we can apply these + + + align:start position:0% +video we'll show how we can apply these +models to predict whether or not a team + + align:start position:0% +models to predict whether or not a team + + + align:start position:0% +models to predict whether or not a team +will make the playoffs \ No newline at end of file diff --git a/n0seIQ7r8xo.txt b/n0seIQ7r8xo.txt new file mode 100644 index 0000000000000000000000000000000000000000..d4cce1b7565f6f66619f0a9e7dc26d96dc36c049 --- /dev/null +++ b/n0seIQ7r8xo.txt @@ -0,0 +1,15803 @@ +align:start position:0% + +and then on Thursday we'll have these I + + align:start position:0% +and then on Thursday we'll have these I + + + align:start position:0% +and then on Thursday we'll have these I +also want to mention if the towards the + + align:start position:0% +also want to mention if the towards the + + + align:start position:0% +also want to mention if the towards the +end of lecture today we'll have the um + + align:start position:0% +end of lecture today we'll have the um + + + align:start position:0% +end of lecture today we'll have the um +the uh course + + align:start position:0% +the uh course + + + align:start position:0% +the uh course +evaluations for you to fill out okay be + + align:start position:0% +evaluations for you to fill out okay be + + + align:start position:0% +evaluations for you to fill out okay be +before we start the the fal lecture for + + align:start position:0% +before we start the the fal lecture for + + + align:start position:0% +before we start the the fal lecture for +for today I want to for those of you who + + align:start position:0% +for today I want to for those of you who + + + align:start position:0% +for today I want to for those of you who +are here last time uh I wanted to go + + align:start position:0% +are here last time uh I wanted to go + + + align:start position:0% +are here last time uh I wanted to go +over um something that we had talked + + align:start position:0% +over um something that we had talked + + + align:start position:0% +over um something that we had talked +about we didn't have time to go through + + align:start position:0% +about we didn't have time to go through + + + align:start position:0% +about we didn't have time to go through +how you would do these calculations and + + align:start position:0% +how you would do these calculations and + + + align:start position:0% +how you would do these calculations and +uh uh from the last handout which was + + align:start position:0% +uh uh from the last handout which was + + + align:start position:0% +uh uh from the last handout which was +handout 37 or 36 + + align:start position:0% +handout 37 or 36 + + + align:start position:0% +handout 37 or 36 +um on slide 27 there was a question that + + align:start position:0% +um on slide 27 there was a question that + + + align:start position:0% +um on slide 27 there was a question that +a couple of questions that we were + + align:start position:0% +a couple of questions that we were + + + align:start position:0% +a couple of questions that we were +asking and uh I thought we just spend + + align:start position:0% +asking and uh I thought we just spend + + + align:start position:0% +asking and uh I thought we just spend +about 5 minutes before we start the uh + + align:start position:0% +about 5 minutes before we start the uh + + + align:start position:0% +about 5 minutes before we start the uh +today's formal lecture uh going through + + align:start position:0% +today's formal lecture uh going through + + + align:start position:0% +today's formal lecture uh going through +this at least on the board so people + + align:start position:0% +this at least on the board so people + + + align:start position:0% +this at least on the board so people +have an idea of how to make these fact + + align:start position:0% +have an idea of how to make these fact + + + align:start position:0% +have an idea of how to make these fact +of the envelope calculations so the what + + align:start position:0% +of the envelope calculations so the what + + + align:start position:0% +of the envelope calculations so the what +you're being asked to do here is you're + + align:start position:0% +you're being asked to do here is you're + + + align:start position:0% +you're being asked to do here is you're +looking at a silicon mosfet with a uh + + align:start position:0% +looking at a silicon mosfet with a uh + + + align:start position:0% +looking at a silicon mosfet with a uh +these are the source drain extensions + + align:start position:0% +these are the source drain extensions + + + align:start position:0% +these are the source drain extensions +these shallow extensions that have a + + align:start position:0% +these shallow extensions that have a + + + align:start position:0% +these shallow extensions that have a +certain depth XJ these are the Deep + + align:start position:0% +certain depth XJ these are the Deep + + + align:start position:0% +certain depth XJ these are the Deep +source and drain uh um that have been + + align:start position:0% +source and drain uh um that have been + + + align:start position:0% +source and drain uh um that have been +psoc remember the last lecture was all + + align:start position:0% +psoc remember the last lecture was all + + + align:start position:0% +psoc remember the last lecture was all +about psoc so this blue region is + + align:start position:0% +about psoc so this blue region is + + + align:start position:0% +about psoc so this blue region is +supposed to represent a + + align:start position:0% +supposed to represent a + + + align:start position:0% +supposed to represent a +pilici um a suicided region and then + + align:start position:0% +pilici um a suicided region and then + + + align:start position:0% +pilici um a suicided region and then +there's a metal contact and this is + + align:start position:0% +there's a metal contact and this is + + + align:start position:0% +there's a metal contact and this is +highly schematic but imagine this little + + align:start position:0% +highly schematic but imagine this little + + + align:start position:0% +highly schematic but imagine this little +thing coming down here as uh your + + align:start position:0% +thing coming down here as uh your + + + align:start position:0% +thing coming down here as uh your +aluminum metal or whatever uh coming + + align:start position:0% +aluminum metal or whatever uh coming + + + align:start position:0% +aluminum metal or whatever uh coming +down and touching uh the solide and it + + align:start position:0% +down and touching uh the solide and it + + + align:start position:0% +down and touching uh the solide and it +spaced a certain distance the metal + + align:start position:0% +spaced a certain distance the metal + + + align:start position:0% +spaced a certain distance the metal +contact is by by um an insulator um from + + align:start position:0% +contact is by by um an insulator um from + + + align:start position:0% +contact is by by um an insulator um from +from this point here where the soloc + + align:start position:0% +from this point here where the soloc + + + align:start position:0% +from this point here where the soloc +starts and so what we're asked to do is + + align:start position:0% +starts and so what we're asked to do is + + + align:start position:0% +starts and so what we're asked to do is +to calculate separately three resistors + + align:start position:0% +to calculate separately three resistors + + + align:start position:0% +to calculate separately three resistors +that are in this problem there's this + + align:start position:0% +that are in this problem there's this + + + align:start position:0% +that are in this problem there's this +resistor here which represents the + + align:start position:0% +resistor here which represents the + + + align:start position:0% +resistor here which represents the +resistance of the sourc drain extension + + align:start position:0% +resistance of the sourc drain extension + + + align:start position:0% +resistance of the sourc drain extension +as the current flows through the channel + + align:start position:0% +as the current flows through the channel + + + align:start position:0% +as the current flows through the channel +into the extension which is underneath + + align:start position:0% +into the extension which is underneath + + + align:start position:0% +into the extension which is underneath +the spacer and then there's a resistance + + align:start position:0% +the spacer and then there's a resistance + + + align:start position:0% +the spacer and then there's a resistance +associated with this sheet resistance of + + align:start position:0% +associated with this sheet resistance of + + + align:start position:0% +associated with this sheet resistance of +the pilici region because the current + + align:start position:0% +the pilici region because the current + + + align:start position:0% +the pilici region because the current +has to get from this point here to the + + align:start position:0% +has to get from this point here to the + + + align:start position:0% +has to get from this point here to the +point where the metal contact is up here + + align:start position:0% +point where the metal contact is up here + + + align:start position:0% +point where the metal contact is up here +and there then there's the interfacial + + align:start position:0% +and there then there's the interfacial + + + align:start position:0% +and there then there's the interfacial +resistance or the contact resistance + + align:start position:0% +resistance or the contact resistance + + + align:start position:0% +resistance or the contact resistance +associated with this metal contact so + + align:start position:0% +associated with this metal contact so + + + align:start position:0% +associated with this metal contact so +those are the three and uh you know in a + + align:start position:0% +those are the three and uh you know in a + + + align:start position:0% +those are the three and uh you know in a +few minutes here we can just kind of go + + align:start position:0% +few minutes here we can just kind of go + + + align:start position:0% +few minutes here we can just kind of go +through that and I thought it might be + + align:start position:0% +through that and I thought it might be + + + align:start position:0% +through that and I thought it might be +uh useful for us to calculate those so + + align:start position:0% +uh useful for us to calculate those so + + + align:start position:0% +uh useful for us to calculate those so +the first one um what we're really + + align:start position:0% +the first one um what we're really + + + align:start position:0% +the first one um what we're really +trying to we we're asked to to calculate + + align:start position:0% +trying to we we're asked to to calculate + + + align:start position:0% +trying to we we're asked to to calculate +the uh let's figure out the contact + + align:start position:0% +the uh let's figure out the contact + + + align:start position:0% +the uh let's figure out the contact +resistance so you're given the specific + + align:start position:0% +resistance so you're given the specific + + + align:start position:0% +resistance so you're given the specific +contact resistivity which we talked + + align:start position:0% +contact resistivity which we talked + + + align:start position:0% +contact resistivity which we talked +about in the last lecture as 2 and2 * 10 + + align:start position:0% +about in the last lecture as 2 and2 * 10 + + + align:start position:0% +about in the last lecture as 2 and2 * 10 +the uh- + + align:start position:0% +the uh- + + + align:start position:0% +the uh- +7 10 Theus 7 and that has units of + + align:start position:0% +7 10 Theus 7 and that has units of + + + align:start position:0% +7 10 Theus 7 and that has units of +centimet squared + + align:start position:0% +centimet squared + + + align:start position:0% +centimet squared +right it's it's a resistance times an + + align:start position:0% +right it's it's a resistance times an + + + align:start position:0% +right it's it's a resistance times an +area and if I take that if I to get the + + align:start position:0% +area and if I take that if I to get the + + + align:start position:0% +area and if I take that if I to get the +contact resistance R of that contact I + + align:start position:0% +contact resistance R of that contact I + + + align:start position:0% +contact resistance R of that contact I +just have to take that row subs value + + align:start position:0% +just have to take that row subs value + + + align:start position:0% +just have to take that row subs value +and divide it by the area of the + + align:start position:0% +and divide it by the area of the + + + align:start position:0% +and divide it by the area of the +contact UM and you're told that the area + + align:start position:0% +contact UM and you're told that the area + + + align:start position:0% +contact UM and you're told that the area +of the contact in in number one there on + + align:start position:0% +of the contact in in number one there on + + + align:start position:0% +of the contact in in number one there on +the slide is 02 by one uh Square Micron + + align:start position:0% +the slide is 02 by one uh Square Micron + + + align:start position:0% +the slide is 02 by one uh Square Micron +so that's just going to be 2.5 * 10us + + align:start position:0% +so that's just going to be 2.5 * 10us + + + align:start position:0% +so that's just going to be 2.5 * 10us +7th over uh 0.25 so the numbers are easy + + align:start position:0% +7th over uh 0.25 so the numbers are easy + + + align:start position:0% +7th over uh 0.25 so the numbers are easy +um times 10 the minus 8 square cenm + + align:start position:0% +um times 10 the minus 8 square cenm + + + align:start position:0% +um times 10 the minus 8 square cenm +right because uh one micron is 10us 4 uh + + align:start position:0% +right because uh one micron is 10us 4 uh + + + align:start position:0% +right because uh one micron is 10us 4 uh +centimeters and you have to square + + align:start position:0% +centimeters and you have to square + + + align:start position:0% +centimeters and you have to square +that so I end up you just calculate this + + align:start position:0% +that so I end up you just calculate this + + + align:start position:0% +that so I end up you just calculate this +out and you end up with + + align:start position:0% +out and you end up with + + + align:start position:0% +out and you end up with +100 100 ohms for the contact resistance + + align:start position:0% +100 100 ohms for the contact resistance + + + align:start position:0% +100 100 ohms for the contact resistance +that's so that's the resistance between + + align:start position:0% +that's so that's the resistance between + + + align:start position:0% +that's so that's the resistance between +the metal and this contact right here + + align:start position:0% +the metal and this contact right here + + + align:start position:0% +the metal and this contact right here +flowing through this face uh given a + + align:start position:0% +flowing through this face uh given a + + + align:start position:0% +flowing through this face uh given a +contact area of that size uh so that'd + + align:start position:0% +contact area of that size uh so that'd + + + align:start position:0% +contact area of that size uh so that'd +be sort of kind of the state-of-the-art + + align:start position:0% +be sort of kind of the state-of-the-art + + + align:start position:0% +be sort of kind of the state-of-the-art +contact so you have about 100 ohms + + align:start position:0% +contact so you have about 100 ohms + + + align:start position:0% +contact so you have about 100 ohms +associated with + + align:start position:0% +associated with + + + align:start position:0% +associated with +that you also want to calculate the + + align:start position:0% +that you also want to calculate the + + + align:start position:0% +that you also want to calculate the +resistor shown here by this little + + align:start position:0% +resistor shown here by this little + + + align:start position:0% +resistor shown here by this little +resistor here estimate what this + + align:start position:0% +resistor here estimate what this + + + align:start position:0% +resistor here estimate what this +resistor is for the current flowing from + + align:start position:0% +resistor is for the current flowing from + + + align:start position:0% +resistor is for the current flowing from +this point to the point where it get it + + align:start position:0% +this point to the point where it get it + + + align:start position:0% +this point to the point where it get it +just gets into the + + align:start position:0% +just gets into the + + + align:start position:0% +just gets into the +contact well that's going to be + + align:start position:0% +contact well that's going to be + + + align:start position:0% +contact well that's going to be +dominated by the sheet resistance of the + + align:start position:0% +dominated by the sheet resistance of the + + + align:start position:0% +dominated by the sheet resistance of the +pilicide of this blue region right so if + + align:start position:0% +pilicide of this blue region right so if + + + align:start position:0% +pilicide of this blue region right so if +we know the sheet resistance and we + + align:start position:0% +we know the sheet resistance and we + + + align:start position:0% +we know the sheet resistance and we +divide by the thickness we can we can + + align:start position:0% +divide by the thickness we can we can + + + align:start position:0% +divide by the thickness we can we can +calculate for any sheet you can always + + align:start position:0% +calculate for any sheet you can always + + + align:start position:0% +calculate for any sheet you can always +calculate um the the resistance so to + + align:start position:0% +calculate um the the resistance so to + + + align:start position:0% +calculate um the the resistance so to +get the sheet resistance of the + + align:start position:0% + + + + align:start position:0% + +pilicide well you're given its + + align:start position:0% +pilicide well you're given its + + + align:start position:0% +pilicide well you're given its +resistivity it's 15 * 10- 6 ohm + + align:start position:0% +resistivity it's 15 * 10- 6 ohm + + + align:start position:0% +resistivity it's 15 * 10- 6 ohm +centimeter so it's just going to be its + + align:start position:0% +centimeter so it's just going to be its + + + align:start position:0% +centimeter so it's just going to be its +resistivity row divided by the thickness + + align:start position:0% +resistivity row divided by the thickness + + + align:start position:0% +resistivity row divided by the thickness +of the + + align:start position:0% +of the + + + align:start position:0% +of the +sheet so that's 15 * 10us 6 ohm + + align:start position:0% +sheet so that's 15 * 10us 6 ohm + + + align:start position:0% +sheet so that's 15 * 10us 6 ohm +centimeter remember that's a resistivity + + align:start position:0% +centimeter remember that's a resistivity + + + align:start position:0% +centimeter remember that's a resistivity +now it's not a specific contact + + align:start position:0% +now it's not a specific contact + + + align:start position:0% +now it's not a specific contact +resistance and you are told the + + align:start position:0% +resistance and you are told the + + + align:start position:0% +resistance and you are told the +thickness of that sheet roughly and I'm + + align:start position:0% +thickness of that sheet roughly and I'm + + + align:start position:0% +thickness of that sheet roughly and I'm +going to ignore the doped region down + + align:start position:0% +going to ignore the doped region down + + + align:start position:0% +going to ignore the doped region down +here because this is a metal it's a + + align:start position:0% +here because this is a metal it's a + + + align:start position:0% +here because this is a metal it's a +silicide it has a much lower resistance + + align:start position:0% +silicide it has a much lower resistance + + + align:start position:0% +silicide it has a much lower resistance +than the Silicon so I'm going to ignore + + align:start position:0% +than the Silicon so I'm going to ignore + + + align:start position:0% +than the Silicon so I'm going to ignore +that we're just going to calculate the + + align:start position:0% +that we're just going to calculate the + + + align:start position:0% +that we're just going to calculate the +resistivity of that metal + + align:start position:0% +resistivity of that metal + + + align:start position:0% +resistivity of that metal +sheet and that thickness is 4 * 10us + + align:start position:0% +sheet and that thickness is 4 * 10us + + + align:start position:0% +sheet and that thickness is 4 * 10us +6 cm so the centimeters go out and you + + align:start position:0% +6 cm so the centimeters go out and you + + + align:start position:0% +6 cm so the centimeters go out and you +end up with a certain resistance about + + align:start position:0% +end up with a certain resistance about + + + align:start position:0% +end up with a certain resistance about +3.75 ohms per square remember that's a + + align:start position:0% +3.75 ohms per square remember that's a + + + align:start position:0% +3.75 ohms per square remember that's a +sheet resistance so that's an ohms per + + align:start position:0% +sheet resistance so that's an ohms per + + + align:start position:0% +sheet resistance so that's an ohms per +square + + align:start position:0% +square + + + align:start position:0% +square +sheet as for a current flowing through a + + align:start position:0% +sheet as for a current flowing through a + + + align:start position:0% +sheet as for a current flowing through a +sheet we talked about this uh that is a + + align:start position:0% +sheet we talked about this uh that is a + + + align:start position:0% +sheet we talked about this uh that is a +square so going in this face coming out + + align:start position:0% +square so going in this face coming out + + + align:start position:0% +square so going in this face coming out +that face where this length and this + + align:start position:0% +that face where this length and this + + + align:start position:0% +that face where this length and this +width are equal that's the definition of + + align:start position:0% +width are equal that's the definition of + + + align:start position:0% +width are equal that's the definition of +the sheet resistance so it's about about + + align:start position:0% +the sheet resistance so it's about about + + + align:start position:0% +the sheet resistance so it's about about +four ohms per square something like + + align:start position:0% +four ohms per square something like + + + align:start position:0% +four ohms per square something like +that then we need to know once you know + + align:start position:0% +that then we need to know once you know + + + align:start position:0% +that then we need to know once you know +the sheet resistance the nice thing + + align:start position:0% +the sheet resistance the nice thing + + + align:start position:0% +the sheet resistance the nice thing +about once you know the sheet resistance + + align:start position:0% +about once you know the sheet resistance + + + align:start position:0% +about once you know the sheet resistance +that tells you the resistance going + + align:start position:0% +that tells you the resistance going + + + align:start position:0% +that tells you the resistance going +through a square you just use geometry + + align:start position:0% +through a square you just use geometry + + + align:start position:0% +through a square you just use geometry +considerations how many squares does the + + align:start position:0% +considerations how many squares does the + + + align:start position:0% +considerations how many squares does the +current go through and flowing from this + + align:start position:0% +current go through and flowing from this + + + align:start position:0% +current go through and flowing from this +point here to the + + align:start position:0% +point here to the + + + align:start position:0% +point here to the +contact well it's a half Micron wall and + + align:start position:0% +contact well it's a half Micron wall and + + + align:start position:0% +contact well it's a half Micron wall and +it's a micron into the page so that's a + + align:start position:0% +it's a micron into the page so that's a + + + align:start position:0% +it's a micron into the page so that's a +half a + + align:start position:0% +half a + + + align:start position:0% +half a +square basically so because it because + + align:start position:0% +square basically so because it because + + + align:start position:0% +square basically so because it because +it it's it looks something like this + + align:start position:0% +it it's it looks something like this + + + align:start position:0% +it it's it looks something like this +it's a half Micron Mo but it goes a + + align:start position:0% +it's a half Micron Mo but it goes a + + + align:start position:0% +it's a half Micron Mo but it goes a +micron into the board into the page so + + align:start position:0% +micron into the board into the page so + + + align:start position:0% +micron into the board into the page so +this is 0 five and this is one so by + + align:start position:0% +this is 0 five and this is one so by + + + align:start position:0% +this is 0 five and this is one so by +definition that's half a square because + + align:start position:0% +definition that's half a square because + + + align:start position:0% +definition that's half a square because +if it were a full Square there'd be two + + align:start position:0% +if it were a full Square there'd be two + + + align:start position:0% +if it were a full Square there'd be two +of these right next to each other so so + + align:start position:0% +of these right next to each other so so + + + align:start position:0% +of these right next to each other so so +then you can just get the resistance of + + align:start position:0% +then you can just get the resistance of + + + align:start position:0% +then you can just get the resistance of +the pilicide + + align:start position:0% +the pilicide + + + align:start position:0% +the pilicide +to be uh 3.8 ohms per square times a + + align:start position:0% +to be uh 3.8 ohms per square times a + + + align:start position:0% +to be uh 3.8 ohms per square times a +half a + + align:start position:0% +half a + + + align:start position:0% +half a +square and you end up with uh about uh + + align:start position:0% +square and you end up with uh about uh + + + align:start position:0% +square and you end up with uh about uh +1.9 ohms very small comparatively + + align:start position:0% +1.9 ohms very small comparatively + + + align:start position:0% +1.9 ohms very small comparatively +speaking couple Waters of magnitude + + align:start position:0% +speaking couple Waters of magnitude + + + align:start position:0% +speaking couple Waters of magnitude +maybe Factor 50 less than than the + + align:start position:0% +maybe Factor 50 less than than the + + + align:start position:0% +maybe Factor 50 less than than the +contact + + align:start position:0% + + + + align:start position:0% + +resistance okay so that seems reasonable + + align:start position:0% +resistance okay so that seems reasonable + + + align:start position:0% +resistance okay so that seems reasonable +and then uh because it's a metal and and + + align:start position:0% +and then uh because it's a metal and and + + + align:start position:0% +and then uh because it's a metal and and +and there uh so it has a very low sheet + + align:start position:0% +and there uh so it has a very low sheet + + + align:start position:0% +and there uh so it has a very low sheet +is this so the resistance is + + align:start position:0% +is this so the resistance is + + + align:start position:0% +is this so the resistance is +small so on the final one number three + + align:start position:0% +small so on the final one number three + + + align:start position:0% +small so on the final one number three +which you're + + align:start position:0% +which you're + + + align:start position:0% +which you're +asked now we're going to be + + align:start position:0% +asked now we're going to be + + + align:start position:0% +asked now we're going to be +calculating the source Trin extension + + align:start position:0% +calculating the source Trin extension + + + align:start position:0% +calculating the source Trin extension +resistance so what's the resistance + + align:start position:0% +resistance so what's the resistance + + + align:start position:0% +resistance so what's the resistance +associated with this very thin uh this + + align:start position:0% +associated with this very thin uh this + + + align:start position:0% +associated with this very thin uh this +very shallow Junction depth XJ so this + + align:start position:0% +very shallow Junction depth XJ so this + + + align:start position:0% +very shallow Junction depth XJ so this +little resistor right here so the + + align:start position:0% +little resistor right here so the + + + align:start position:0% +little resistor right here so the +current comes out of the channel has to + + align:start position:0% +current comes out of the channel has to + + + align:start position:0% +current comes out of the channel has to +flow in that sour Trin extension before + + align:start position:0% +flow in that sour Trin extension before + + + align:start position:0% +flow in that sour Trin extension before +it hits the + + align:start position:0% +it hits the + + + align:start position:0% +it hits the +suicide well again that's a very similar + + align:start position:0% +suicide well again that's a very similar + + + align:start position:0% +suicide well again that's a very similar +situation where we just need to C + + align:start position:0% +situation where we just need to C + + + align:start position:0% +situation where we just need to C +calculate a sheet resistance and from + + align:start position:0% +calculate a sheet resistance and from + + + align:start position:0% +calculate a sheet resistance and from +sheet resistance we figure out the + + align:start position:0% +sheet resistance we figure out the + + + align:start position:0% +sheet resistance we figure out the +number of squares from the geometry and + + align:start position:0% +number of squares from the geometry and + + + align:start position:0% +number of squares from the geometry and +we get the resistance so again so for + + align:start position:0% +we get the resistance so again so for + + + align:start position:0% +we get the resistance so again so for +the source drain + + align:start position:0% + + + + align:start position:0% + +extension for that region we're given uh + + align:start position:0% +extension for that region we're given uh + + + align:start position:0% +extension for that region we're given uh +we're told the resistivity row is 5 * + + align:start position:0% +we're told the resistivity row is 5 * + + + align:start position:0% +we're told the resistivity row is 5 * +10us 4 ohm cimer and um we have uh we + + align:start position:0% +10us 4 ohm cimer and um we have uh we + + + align:start position:0% +10us 4 ohm cimer and um we have uh we +know the number of squares and we have a + + align:start position:0% +know the number of squares and we have a + + + align:start position:0% +know the number of squares and we have a +thickness of that region + + align:start position:0% +thickness of that region + + + align:start position:0% +thickness of that region +so I can get the uh sheet + + align:start position:0% +so I can get the uh sheet + + + align:start position:0% +so I can get the uh sheet +resistance again it's just the + + align:start position:0% +resistance again it's just the + + + align:start position:0% +resistance again it's just the +resistivity divided by the thickness of + + align:start position:0% +resistivity divided by the thickness of + + + align:start position:0% +resistivity divided by the thickness of +the region so that's 5 * 10us + + align:start position:0% +the region so that's 5 * 10us + + + align:start position:0% +the region so that's 5 * 10us +4 cimer / by I think it was an easy + + align:start position:0% +4 cimer / by I think it was an easy + + + align:start position:0% +4 cimer / by I think it was an easy +number 500 uh anging so that's 5 * 10us + + align:start position:0% +number 500 uh anging so that's 5 * 10us + + + align:start position:0% +number 500 uh anging so that's 5 * 10us +6 cm and that goes out and we end up + + align:start position:0% +6 cm and that goes out and we end up + + + align:start position:0% +6 cm and that goes out and we end up +with uh about 100 ohms per + + align:start position:0% +with uh about 100 ohms per + + + align:start position:0% +with uh about 100 ohms per +square that's a typical shallow Junction + + align:start position:0% +square that's a typical shallow Junction + + + align:start position:0% +square that's a typical shallow Junction +for a shallow Junction uh shallow being + + align:start position:0% +for a shallow Junction uh shallow being + + + align:start position:0% +for a shallow Junction uh shallow being +500 angstroms or less uh you dop it very + + align:start position:0% +500 angstroms or less uh you dop it very + + + align:start position:0% +500 angstroms or less uh you dop it very +heavily we said this is dope 2 10 the 20 + + align:start position:0% +heavily we said this is dope 2 10 the 20 + + + align:start position:0% +heavily we said this is dope 2 10 the 20 +with r Snick or whatever and it's about + + align:start position:0% +with r Snick or whatever and it's about + + + align:start position:0% +with r Snick or whatever and it's about +100 ohms per + + align:start position:0% +100 ohms per + + + align:start position:0% +100 ohms per +square as the sheet resistance now again + + align:start position:0% +square as the sheet resistance now again + + + align:start position:0% +square as the sheet resistance now again +looking at this how many squares does + + align:start position:0% +looking at this how many squares does + + + align:start position:0% +looking at this how many squares does +this well the distance from this point + + align:start position:0% +this well the distance from this point + + + align:start position:0% +this well the distance from this point +in the channel to the point where it + + align:start position:0% +in the channel to the point where it + + + align:start position:0% +in the channel to the point where it +contacts a suicide that we're told that + + align:start position:0% +contacts a suicide that we're told that + + + align:start position:0% +contacts a suicide that we're told that +space or width is point one microns so + + align:start position:0% +space or width is point one microns so + + + align:start position:0% +space or width is point one microns so +that's 0.1 and into the board is one + + align:start position:0% +that's 0.1 and into the board is one + + + align:start position:0% +that's 0.1 and into the board is one +again so that's a tenth of a square + + align:start position:0% +again so that's a tenth of a square + + + align:start position:0% +again so that's a tenth of a square +so then we can just get the resistance + + align:start position:0% +so then we can just get the resistance + + + align:start position:0% +so then we can just get the resistance +of the source drain + + align:start position:0% +of the source drain + + + align:start position:0% +of the source drain +extension then is just the sheet + + align:start position:0% +extension then is just the sheet + + + align:start position:0% +extension then is just the sheet +resistance times the number of + + align:start position:0% +resistance times the number of + + + align:start position:0% +resistance times the number of +squares so that's 100 ohms per square + + align:start position:0% +squares so that's 100 ohms per square + + + align:start position:0% +squares so that's 100 ohms per square +time 0.1 + + align:start position:0% +time 0.1 + + + align:start position:0% +time 0.1 +squares and then we end up with 10 + + align:start position:0% +squares and then we end up with 10 + + + align:start position:0% +squares and then we end up with 10 +ohms so that resistors roughly I mean + + align:start position:0% +ohms so that resistors roughly I mean + + + align:start position:0% +ohms so that resistors roughly I mean +it's this is a very crude estimate that + + align:start position:0% +it's this is a very crude estimate that + + + align:start position:0% +it's this is a very crude estimate that +that resistor here so this this resistor + + align:start position:0% +that resistor here so this this resistor + + + align:start position:0% +that resistor here so this this resistor +here is about 10 ohms this little sheet + + align:start position:0% +here is about 10 ohms this little sheet + + + align:start position:0% +here is about 10 ohms this little sheet +here represents so about a couple of + + align:start position:0% +here represents so about a couple of + + + align:start position:0% +here represents so about a couple of +ohms the big resistance is is what the + + align:start position:0% +ohms the big resistance is is what the + + + align:start position:0% +ohms the big resistance is is what the +big resistance is the 100 ohms it's the + + align:start position:0% +big resistance is the 100 ohms it's the + + + align:start position:0% +big resistance is the 100 ohms it's the +contact resistance because we have uh a + + align:start position:0% +contact resistance because we have uh a + + + align:start position:0% +contact resistance because we have uh a +finite specific contact resistivity 2 + + align:start position:0% +finite specific contact resistivity 2 + + + align:start position:0% +finite specific contact resistivity 2 +half * 10- 7 ohm cenm squar and we're + + align:start position:0% +half * 10- 7 ohm cenm squar and we're + + + align:start position:0% +half * 10- 7 ohm cenm squar and we're +trying to make contact in a very small + + align:start position:0% +trying to make contact in a very small + + + align:start position:0% +trying to make contact in a very small +area so what's the solution well I can + + align:start position:0% +area so what's the solution well I can + + + align:start position:0% +area so what's the solution well I can +make the area bigger make the devices + + align:start position:0% +make the area bigger make the devices + + + align:start position:0% +make the area bigger make the devices +bigger on the chip I get fewer devices + + align:start position:0% +bigger on the chip I get fewer devices + + + align:start position:0% +bigger on the chip I get fewer devices +that's not good or we have to scale this + + align:start position:0% +that's not good or we have to scale this + + + align:start position:0% +that's not good or we have to scale this +number according to the HRS remember + + align:start position:0% +number according to the HRS remember + + + align:start position:0% +number according to the HRS remember +this number is going to have to go down + + align:start position:0% +this number is going to have to go down + + + align:start position:0% +this number is going to have to go down +in in in 2003 TRS wants this number to + + align:start position:0% +in in in 2003 TRS wants this number to + + + align:start position:0% +in in in 2003 TRS wants this number to +be about 2 * 10us 7 um so it's already + + align:start position:0% +be about 2 * 10us 7 um so it's already + + + align:start position:0% +be about 2 * 10us 7 um so it's already +supposed to be lower than that and over + + align:start position:0% +supposed to be lower than that and over + + + align:start position:0% +supposed to be lower than that and over +the next 10 years it's supposed to be + + align:start position:0% +the next 10 years it's supposed to be + + + align:start position:0% +the next 10 years it's supposed to be +lowered by a factor of three or four um + + align:start position:0% +lowered by a factor of three or four um + + + align:start position:0% +lowered by a factor of three or four um +so that this this number of 100 ohms + + align:start position:0% +so that this this number of 100 ohms + + + align:start position:0% +so that this this number of 100 ohms +gets lower or doesn't certainly does not + + align:start position:0% +gets lower or doesn't certainly does not + + + align:start position:0% +gets lower or doesn't certainly does not +increase as we scale the devices but + + align:start position:0% +increase as we scale the devices but + + + align:start position:0% +increase as we scale the devices but +just kind of gives you a rough idea of + + align:start position:0% +just kind of gives you a rough idea of + + + align:start position:0% +just kind of gives you a rough idea of +what the big contributions are um if you + + align:start position:0% +what the big contributions are um if you + + + align:start position:0% +what the big contributions are um if you +do it right again if if you didn't get + + align:start position:0% +do it right again if if you didn't get + + + align:start position:0% +do it right again if if you didn't get +enough doping in this shallow sour + + align:start position:0% +enough doping in this shallow sour + + + align:start position:0% +enough doping in this shallow sour +strand extension this 10 ohm number + + align:start position:0% +strand extension this 10 ohm number + + + align:start position:0% +strand extension this 10 ohm number +could go up depending on your your + + align:start position:0% +could go up depending on your your + + + align:start position:0% +could go up depending on your your +Junction depth how you scale that and + + align:start position:0% +Junction depth how you scale that and + + + align:start position:0% +Junction depth how you scale that and +and you're you're doping but these are + + align:start position:0% +and you're you're doping but these are + + + align:start position:0% +and you're you're doping but these are +these are simple calculations you can do + + align:start position:0% +these are simple calculations you can do + + + align:start position:0% +these are simple calculations you can do +sort of back of the envelope and and we + + align:start position:0% +sort of back of the envelope and and we + + + align:start position:0% +sort of back of the envelope and and we +didn't get to go through that last time + + align:start position:0% +didn't get to go through that last time + + + align:start position:0% +didn't get to go through that last time +we presented it but this gives you an + + align:start position:0% +we presented it but this gives you an + + + align:start position:0% +we presented it but this gives you an +idea of kind of how those numbers work + + align:start position:0% +idea of kind of how those numbers work + + + align:start position:0% +idea of kind of how those numbers work +out any any questions on that or on the + + align:start position:0% +out any any questions on that or on the + + + align:start position:0% +out any any questions on that or on the +contact we we only spent one lecture on + + align:start position:0% +contact we we only spent one lecture on + + + align:start position:0% +contact we we only spent one lecture on +contact so uh there's a little bit of + + align:start position:0% +contact so uh there's a little bit of + + + align:start position:0% +contact so uh there's a little bit of +this in uh in chapter 11 although I + + align:start position:0% +this in uh in chapter 11 although I + + + align:start position:0% +this in uh in chapter 11 although I +don't think there's some some a specific + + align:start position:0% +don't think there's some some a specific + + + align:start position:0% +don't think there's some some a specific +example of a moset like + + align:start position:0% + + + + align:start position:0% + +this okay so let's go on then to um + + align:start position:0% +this okay so let's go on then to um + + + align:start position:0% +this okay so let's go on then to um +today's uh actual material which is um + + align:start position:0% +today's uh actual material which is um + + + align:start position:0% +today's uh actual material which is um +going to be um a little bit of a + + align:start position:0% +going to be um a little bit of a + + + align:start position:0% +going to be um a little bit of a +Divergence to a certain extent from the + + align:start position:0% +Divergence to a certain extent from the + + + align:start position:0% +Divergence to a certain extent from the +uh the other lectures this material is + + align:start position:0% +uh the other lectures this material is + + + align:start position:0% +uh the other lectures this material is +not in the text this is all sort of um + + align:start position:0% +not in the text this is all sort of um + + + align:start position:0% +not in the text this is all sort of um +uh more kind of uh upto-date sort of + + align:start position:0% +uh more kind of uh upto-date sort of + + + align:start position:0% +uh more kind of uh upto-date sort of +research material that that's come out + + align:start position:0% +research material that that's come out + + + align:start position:0% +research material that that's come out +and has yet not yet been put into a + + align:start position:0% +and has yet not yet been put into a + + + align:start position:0% +and has yet not yet been put into a +textbook but you have the + + align:start position:0% +textbook but you have the + + + align:start position:0% +textbook but you have the +handouts um so what I want to talk about + + align:start position:0% +handouts um so what I want to talk about + + + align:start position:0% +handouts um so what I want to talk about +well what we've talked about so far for + + align:start position:0% +well what we've talked about so far for + + + align:start position:0% +well what we've talked about so far for +semiconductors is just using pure + + align:start position:0% +semiconductors is just using pure + + + align:start position:0% +semiconductors is just using pure +silicon pure pure silicon Wafers uh and + + align:start position:0% +silicon pure pure silicon Wafers uh and + + + align:start position:0% +silicon pure pure silicon Wafers uh and +pure silicon materials to make uh sea + + align:start position:0% +pure silicon materials to make uh sea + + + align:start position:0% +pure silicon materials to make uh sea +moss to make uh Moss fets um it turns + + align:start position:0% +moss to make uh Moss fets um it turns + + + align:start position:0% +moss to make uh Moss fets um it turns +out if we use epitaxial growth we did + + align:start position:0% +out if we use epitaxial growth we did + + + align:start position:0% +out if we use epitaxial growth we did +spend a little time talking about + + align:start position:0% +spend a little time talking about + + + align:start position:0% +spend a little time talking about +epitaxial growth of silicon by by CBD or + + align:start position:0% +epitaxial growth of silicon by by CBD or + + + align:start position:0% +epitaxial growth of silicon by by CBD or +or some similar technique if we use + + align:start position:0% +or some similar technique if we use + + + align:start position:0% +or some similar technique if we use +epaxal growth you can mix in small + + align:start position:0% +epaxal growth you can mix in small + + + align:start position:0% +epaxal growth you can mix in small +amounts of germanium into the Silicon + + align:start position:0% +amounts of germanium into the Silicon + + + align:start position:0% +amounts of germanium into the Silicon +material and make an alloy called + + align:start position:0% +material and make an alloy called + + + align:start position:0% +material and make an alloy called +silicon germanium or you can mix in even + + align:start position:0% +silicon germanium or you can mix in even + + + align:start position:0% +silicon germanium or you can mix in even +small amount even smaller amounts of + + align:start position:0% +small amount even smaller amounts of + + + align:start position:0% +small amount even smaller amounts of +carbon maybe 1% or so and make an alloy + + align:start position:0% +carbon maybe 1% or so and make an alloy + + + align:start position:0% +carbon maybe 1% or so and make an alloy +of the silicon and car carbon and people + + align:start position:0% +of the silicon and car carbon and people + + + align:start position:0% +of the silicon and car carbon and people +are doing this and some of these Alloys + + align:start position:0% +are doing this and some of these Alloys + + + align:start position:0% +are doing this and some of these Alloys +are used today in modern production + + align:start position:0% +are used today in modern production + + + align:start position:0% +are used today in modern production +devices and Manufacturing so I just + + align:start position:0% +devices and Manufacturing so I just + + + align:start position:0% +devices and Manufacturing so I just +wanted to go through some of the + + align:start position:0% +wanted to go through some of the + + + align:start position:0% +wanted to go through some of the +important material electronic properties + + align:start position:0% +important material electronic properties + + + align:start position:0% +important material electronic properties +of these newer + + align:start position:0% +of these newer + + + align:start position:0% +of these newer +semiconductors uh and how how the layers + + align:start position:0% +semiconductors uh and how how the layers + + + align:start position:0% +semiconductors uh and how how the layers +are processed to a certain extent and + + align:start position:0% +are processed to a certain extent and + + + align:start position:0% +are processed to a certain extent and +and what's some of the issues in + + align:start position:0% +and what's some of the issues in + + + align:start position:0% +and what's some of the issues in +research and development that that + + align:start position:0% +research and development that that + + + align:start position:0% +research and development that that +people are + + align:start position:0% +people are + + + align:start position:0% +people are +considering so here on slide two uh what + + align:start position:0% +considering so here on slide two uh what + + + align:start position:0% +considering so here on slide two uh what +I'm showing are some applications of + + align:start position:0% +I'm showing are some applications of + + + align:start position:0% +I'm showing are some applications of +these Alloys these silicon tranium + + align:start position:0% +these Alloys these silicon tranium + + + align:start position:0% +these Alloys these silicon tranium +Alloys and sort of related material like + + align:start position:0% +Alloys and sort of related material like + + + align:start position:0% +Alloys and sort of related material like +Silicon geranium carbon um the first + + align:start position:0% +Silicon geranium carbon um the first + + + align:start position:0% +Silicon geranium carbon um the first +bullet is for a number of time a number + + align:start position:0% +bullet is for a number of time a number + + + align:start position:0% +bullet is for a number of time a number +of years now maybe the last 10 years + + align:start position:0% +of years now maybe the last 10 years + + + align:start position:0% +of years now maybe the last 10 years +silicon germanium has been used in + + align:start position:0% +silicon germanium has been used in + + + align:start position:0% +silicon germanium has been used in +production as the base layer uh in a a + + align:start position:0% +production as the base layer uh in a a + + + align:start position:0% +production as the base layer uh in a a +heterojunction bipolar transistor in a + + align:start position:0% +heterojunction bipolar transistor in a + + + align:start position:0% +heterojunction bipolar transistor in a +bipolar transistor the base layer being + + align:start position:0% +bipolar transistor the base layer being + + + align:start position:0% +bipolar transistor the base layer being +quite thin we haven't talked much about + + align:start position:0% +quite thin we haven't talked much about + + + align:start position:0% +quite thin we haven't talked much about +bipolars in this class this class is + + align:start position:0% +bipolars in this class this class is + + + align:start position:0% +bipolars in this class this class is +mostly about seos making seos devices + + align:start position:0% +mostly about seos making seos devices + + + align:start position:0% +mostly about seos making seos devices +but um it's a thin layer a couple + + align:start position:0% +but um it's a thin layer a couple + + + align:start position:0% +but um it's a thin layer a couple +hundred Anum maybe 200 to 500 Anum thick + + align:start position:0% +hundred Anum maybe 200 to 500 Anum thick + + + align:start position:0% +hundred Anum maybe 200 to 500 Anum thick +this is used in high frequency analog + + align:start position:0% +this is used in high frequency analog + + + align:start position:0% +this is used in high frequency analog +applications generally + + align:start position:0% +applications generally + + + align:start position:0% +applications generally +telecommunications applications base + + align:start position:0% +telecommunications applications base + + + align:start position:0% +telecommunications applications base +stations and things like that and there + + align:start position:0% +stations and things like that and there + + + align:start position:0% +stations and things like that and there +are a number of companies uh maybe half + + align:start position:0% +are a number of companies uh maybe half + + + align:start position:0% +are a number of companies uh maybe half +a dozen or more that manufacture these + + align:start position:0% +a dozen or more that manufacture these + + + align:start position:0% +a dozen or more that manufacture these +and sell these devices um so this for + + align:start position:0% +and sell these devices um so this for + + + align:start position:0% +and sell these devices um so this for +the purpose of uh you know growing thin + + align:start position:0% +the purpose of uh you know growing thin + + + align:start position:0% +the purpose of uh you know growing thin +films this is something that has been + + align:start position:0% +films this is something that has been + + + align:start position:0% +films this is something that has been +done now in manufacturing for some time + + align:start position:0% +done now in manufacturing for some time + + + align:start position:0% +done now in manufacturing for some time +the second bullet refers to uh a little + + align:start position:0% +the second bullet refers to uh a little + + + align:start position:0% +the second bullet refers to uh a little +more uh more advanced type of material + + align:start position:0% +more uh more advanced type of material + + + align:start position:0% +more uh more advanced type of material +and that's just coming in to production + + align:start position:0% +and that's just coming in to production + + + align:start position:0% +and that's just coming in to production +now and these are um layers of relaxed + + align:start position:0% +now and these are um layers of relaxed + + + align:start position:0% +now and these are um layers of relaxed +silicon ger manum or strain silicon + + align:start position:0% +silicon ger manum or strain silicon + + + align:start position:0% +silicon ger manum or strain silicon +germanium I'll talk about what that + + align:start position:0% +germanium I'll talk about what that + + + align:start position:0% +germanium I'll talk about what that +means in in a little while that are used + + align:start position:0% +means in in a little while that are used + + + align:start position:0% +means in in a little while that are used +to induce strain and silicon so these + + align:start position:0% +to induce strain and silicon so these + + + align:start position:0% +to induce strain and silicon so these +layers are used to uh take silicon + + align:start position:0% +layers are used to uh take silicon + + + align:start position:0% +layers are used to uh take silicon +Channel and to either stretch it or + + align:start position:0% +Channel and to either stretch it or + + + align:start position:0% +Channel and to either stretch it or +compress it + + align:start position:0% +compress it + + + align:start position:0% +compress it +mechanically uh and by stretching and + + align:start position:0% +mechanically uh and by stretching and + + + align:start position:0% +mechanically uh and by stretching and +compressing the lce in the channel you + + align:start position:0% +compressing the lce in the channel you + + + align:start position:0% +compressing the lce in the channel you +can enhance the mobility as it turns out + + align:start position:0% +can enhance the mobility as it turns out + + + align:start position:0% +can enhance the mobility as it turns out +enhancing the mobility means you get a + + align:start position:0% +enhancing the mobility means you get a + + + align:start position:0% +enhancing the mobility means you get a +higher current drive for a given voltage + + align:start position:0% +higher current drive for a given voltage + + + align:start position:0% +higher current drive for a given voltage +so that so the devices will switch + + align:start position:0% +so that so the devices will switch + + + align:start position:0% +so that so the devices will switch +faster so uh for enhancing seamoss um + + align:start position:0% +faster so uh for enhancing seamoss um + + + align:start position:0% +faster so uh for enhancing seamoss um +these some of these materials are now in + + align:start position:0% +these some of these materials are now in + + + align:start position:0% +these some of these materials are now in +production Intel has a new Pentium + + align:start position:0% +production Intel has a new Pentium + + + align:start position:0% +production Intel has a new Pentium +that's uh that's in production using + + align:start position:0% +that's uh that's in production using + + + align:start position:0% +that's uh that's in production using +this this type of technique um these + + align:start position:0% +this this type of technique um these + + + align:start position:0% +this this type of technique um these +materials some sometimes silicon + + align:start position:0% +materials some sometimes silicon + + + align:start position:0% +materials some sometimes silicon +geranium can be used as a boron + + align:start position:0% +geranium can be used as a boron + + + align:start position:0% +geranium can be used as a boron +diffusion barrier uh we spent a lot of + + align:start position:0% +diffusion barrier uh we spent a lot of + + + align:start position:0% +diffusion barrier uh we spent a lot of +time in this class talking about the + + align:start position:0% +time in this class talking about the + + + align:start position:0% +time in this class talking about the +fact that Boron is a fast diffuser in + + align:start position:0% +fact that Boron is a fast diffuser in + + + align:start position:0% +fact that Boron is a fast diffuser in +Silicon that's one of the problems with + + align:start position:0% +Silicon that's one of the problems with + + + align:start position:0% +Silicon that's one of the problems with +making shallow Junctions well it turns + + align:start position:0% +making shallow Junctions well it turns + + + align:start position:0% +making shallow Junctions well it turns +out in silic and geranium for reasons + + align:start position:0% +out in silic and geranium for reasons + + + align:start position:0% +out in silic and geranium for reasons +that are not completely understood the + + align:start position:0% +that are not completely understood the + + + align:start position:0% +that are not completely understood the +more geranium you add the slower the + + align:start position:0% +more geranium you add the slower the + + + align:start position:0% +more geranium you add the slower the +Boron diffusion coefficient so if you + + align:start position:0% +Boron diffusion coefficient so if you + + + align:start position:0% +Boron diffusion coefficient so if you +put in 20% geranium the lattice the + + align:start position:0% +put in 20% geranium the lattice the + + + align:start position:0% +put in 20% geranium the lattice the +Boron diffusivity drops by about about a + + align:start position:0% +Boron diffusivity drops by about about a + + + align:start position:0% +Boron diffusivity drops by about about a +factor of 10 in Silicon geranium so + + align:start position:0% +factor of 10 in Silicon geranium so + + + align:start position:0% +factor of 10 in Silicon geranium so +that's a huge Factor um so people may + + align:start position:0% +that's a huge Factor um so people may + + + align:start position:0% +that's a huge Factor um so people may +want to use silicon geranium just as a + + align:start position:0% +want to use silicon geranium just as a + + + align:start position:0% +want to use silicon geranium just as a +means of slowing down B on diffusion uh + + align:start position:0% +means of slowing down B on diffusion uh + + + align:start position:0% +means of slowing down B on diffusion uh +it's used in micro Machining in Ms + + align:start position:0% +it's used in micro Machining in Ms + + + align:start position:0% +it's used in micro Machining in Ms +technology it happens to be an excellent + + align:start position:0% +technology it happens to be an excellent + + + align:start position:0% +technology it happens to be an excellent +Edge stop so there are uh etches wet + + align:start position:0% +Edge stop so there are uh etches wet + + + align:start position:0% +Edge stop so there are uh etches wet +chemical etches primarily wet maybe a + + align:start position:0% +chemical etches primarily wet maybe a + + + align:start position:0% +chemical etches primarily wet maybe a +few dry that uh etch that will stop on + + align:start position:0% +few dry that uh etch that will stop on + + + align:start position:0% +few dry that uh etch that will stop on +Silicon geranium and and and etch + + align:start position:0% +Silicon geranium and and and etch + + + align:start position:0% +Silicon geranium and and and etch +through a silicon a stop on silic + + align:start position:0% +through a silicon a stop on silic + + + align:start position:0% +through a silicon a stop on silic +tranium and vice versa so it can be used + + align:start position:0% +tranium and vice versa so it can be used + + + align:start position:0% +tranium and vice versa so it can be used +as a sort of an edge stop layer + + align:start position:0% +as a sort of an edge stop layer + + + align:start position:0% +as a sort of an edge stop layer +um some people are advocating using I + + align:start position:0% +um some people are advocating using I + + + align:start position:0% +um some people are advocating using I +don't think it's in production that I + + align:start position:0% +don't think it's in production that I + + + align:start position:0% +don't think it's in production that I +know of but poly Crystal and silicon + + align:start position:0% +know of but poly Crystal and silicon + + + align:start position:0% +know of but poly Crystal and silicon +geranium as the gate material people are + + align:start position:0% +geranium as the gate material people are + + + align:start position:0% +geranium as the gate material people are +we've talked in this class the last few + + align:start position:0% +we've talked in this class the last few + + + align:start position:0% +we've talked in this class the last few +lectures about metal gates before they + + align:start position:0% +lectures about metal gates before they + + + align:start position:0% +lectures about metal gates before they +get to metal gates people were + + align:start position:0% +get to metal gates people were + + + align:start position:0% +get to metal gates people were +advocating using uh poly Crystal and + + align:start position:0% +advocating using uh poly Crystal and + + + align:start position:0% +advocating using uh poly Crystal and +silen geranium instead of polycrystal + + align:start position:0% +silen geranium instead of polycrystal + + + align:start position:0% +silen geranium instead of polycrystal +and silicon uh I don't know if that + + align:start position:0% +and silicon uh I don't know if that + + + align:start position:0% +and silicon uh I don't know if that +again if that really is making it into + + align:start position:0% +again if that really is making it into + + + align:start position:0% +again if that really is making it into +production it so geranium is also used + + align:start position:0% +production it so geranium is also used + + + align:start position:0% +production it so geranium is also used +as an infrared photo detector material + + align:start position:0% +as an infrared photo detector material + + + align:start position:0% +as an infrared photo detector material +uh for integrating photage tectures with + + align:start position:0% +uh for integrating photage tectures with + + + align:start position:0% +uh for integrating photage tectures with +silicon + + align:start position:0% +silicon + + + align:start position:0% +silicon +seamless silicon ium carbon is in + + align:start position:0% +seamless silicon ium carbon is in + + + align:start position:0% +seamless silicon ium carbon is in +production now maybe not silicon carbon + + align:start position:0% +production now maybe not silicon carbon + + + align:start position:0% +production now maybe not silicon carbon +but silicon geranium carbon is in + + align:start position:0% +but silicon geranium carbon is in + + + align:start position:0% +but silicon geranium carbon is in +production with very small amounts of + + align:start position:0% +production with very small amounts of + + + align:start position:0% +production with very small amounts of +carbon maybe a half a percent uh as a + + align:start position:0% +carbon maybe a half a percent uh as a + + + align:start position:0% +carbon maybe a half a percent uh as a +way of suppressing Transit enhanced + + align:start position:0% +way of suppressing Transit enhanced + + + align:start position:0% +way of suppressing Transit enhanced +diffusion uh in in in heterog Junction + + align:start position:0% +diffusion uh in in in heterog Junction + + + align:start position:0% +diffusion uh in in in heterog Junction +bipolar transistors so I think some + + align:start position:0% +bipolar transistors so I think some + + + align:start position:0% +bipolar transistors so I think some +somebody's doing a report on that one + + align:start position:0% +somebody's doing a report on that one + + + align:start position:0% +somebody's doing a report on that one +one of the people signed up for that so + + align:start position:0% +one of the people signed up for that so + + + align:start position:0% +one of the people signed up for that so +that's that's kind of a Hot Topic the + + align:start position:0% +that's that's kind of a Hot Topic the + + + align:start position:0% +that's that's kind of a Hot Topic the +use of carbon to uh completely um suck + + align:start position:0% +use of carbon to uh completely um suck + + + align:start position:0% +use of carbon to uh completely um suck +up all the interstitials and then that + + align:start position:0% +up all the interstitials and then that + + + align:start position:0% +up all the interstitials and then that +that that completely changes the teed + + align:start position:0% +that that completely changes the teed + + + align:start position:0% +that that completely changes the teed +effect so these materials have uh quite + + align:start position:0% +effect so these materials have uh quite + + + align:start position:0% +effect so these materials have uh quite +a bit of of application so on on slide + + align:start position:0% +a bit of of application so on on slide + + + align:start position:0% +a bit of of application so on on slide +three this looks like a long outline but + + align:start position:0% +three this looks like a long outline but + + + align:start position:0% +three this looks like a long outline but +I'm just going to touch on it uh after I + + align:start position:0% +I'm just going to touch on it uh after I + + + align:start position:0% +I'm just going to touch on it uh after I +introduce these M the materials going to + + align:start position:0% +introduce these M the materials going to + + + align:start position:0% +introduce these M the materials going to +touch a little bit on the Moss bits and + + align:start position:0% +touch a little bit on the Moss bits and + + + align:start position:0% +touch a little bit on the Moss bits and +the applications of of strain silicon + + align:start position:0% +the applications of of strain silicon + + + align:start position:0% +the applications of of strain silicon +and strain silicon germanian to se Moss + + align:start position:0% +and strain silicon germanian to se Moss + + + align:start position:0% +and strain silicon germanian to se Moss +uh talk a little bit about how the + + align:start position:0% +uh talk a little bit about how the + + + align:start position:0% +uh talk a little bit about how the +materials are grown and about how the + + align:start position:0% +materials are grown and about how the + + + align:start position:0% +materials are grown and about how the +dope is diffuse in these materials and + + align:start position:0% +dope is diffuse in these materials and + + + align:start position:0% +dope is diffuse in these materials and +um a little bit about some newer + + align:start position:0% +um a little bit about some newer + + + align:start position:0% +um a little bit about some newer +material where we're putting them on + + align:start position:0% +material where we're putting them on + + + align:start position:0% +material where we're putting them on +insulator strain silicon on insulator uh + + align:start position:0% +insulator strain silicon on insulator uh + + + align:start position:0% +insulator strain silicon on insulator uh +is is a very kind of a topic of of + + align:start position:0% +is is a very kind of a topic of of + + + align:start position:0% +is is a very kind of a topic of of +research these + + align:start position:0% +research these + + + align:start position:0% +research these +days well if we go to slide four this is + + align:start position:0% +days well if we go to slide four this is + + + align:start position:0% +days well if we go to slide four this is +more of a motivational slide um what + + align:start position:0% +more of a motivational slide um what + + + align:start position:0% +more of a motivational slide um what +what this show the question we're trying + + align:start position:0% +what this show the question we're trying + + + align:start position:0% +what this show the question we're trying +to ask is if you have a Coss circuit + + align:start position:0% +to ask is if you have a Coss circuit + + + align:start position:0% +to ask is if you have a Coss circuit +maybe inverter or something how quickly + + align:start position:0% +maybe inverter or something how quickly + + + align:start position:0% +maybe inverter or something how quickly +can it switch from one state of the zero + + align:start position:0% +can it switch from one state of the zero + + + align:start position:0% +can it switch from one state of the zero +state to the on state the zero state to + + align:start position:0% +state to the on state the zero state to + + + align:start position:0% +state to the on state the zero state to +to the one state for example um and this + + align:start position:0% +to the one state for example um and this + + + align:start position:0% +to the one state for example um and this +the delay in doing that is something + + align:start position:0% +the delay in doing that is something + + + align:start position:0% +the delay in doing that is something +called the gate delay it's usually + + align:start position:0% +called the gate delay it's usually + + + align:start position:0% +called the gate delay it's usually +measured in PE of seconds and that gate + + align:start position:0% +measured in PE of seconds and that gate + + + align:start position:0% +measured in PE of seconds and that gate +delay is something we want to minimize + + align:start position:0% +delay is something we want to minimize + + + align:start position:0% +delay is something we want to minimize +we want to minimize the switching of + + align:start position:0% +we want to minimize the switching of + + + align:start position:0% +we want to minimize the switching of +each gate in the logic uh sequence so + + align:start position:0% +each gate in the logic uh sequence so + + + align:start position:0% +each gate in the logic uh sequence so +that the overall circuit will will uh + + align:start position:0% +that the overall circuit will will uh + + + align:start position:0% +that the overall circuit will will uh +you know can do computation uh faster so + + align:start position:0% +you know can do computation uh faster so + + + align:start position:0% +you know can do computation uh faster so +the gate delay generally if you've taken + + align:start position:0% +the gate delay generally if you've taken + + + align:start position:0% +the gate delay generally if you've taken +classes like 6012 or you've had some + + align:start position:0% +classes like 6012 or you've had some + + + align:start position:0% +classes like 6012 or you've had some +under other undergraduate classes on + + align:start position:0% +under other undergraduate classes on + + + align:start position:0% +under other undergraduate classes on +seam loss you know as you scale the gate + + align:start position:0% +seam loss you know as you scale the gate + + + align:start position:0% +seam loss you know as you scale the gate +length that's why we're making the gate + + align:start position:0% +length that's why we're making the gate + + + align:start position:0% +length that's why we're making the gate +length shorter and shorter the gate + + align:start position:0% +length shorter and shorter the gate + + + align:start position:0% +length shorter and shorter the gate +delay goes down this is just actually + + align:start position:0% +delay goes down this is just actually + + + align:start position:0% +delay goes down this is just actually +some data showing how it does indeed + + align:start position:0% +some data showing how it does indeed + + + align:start position:0% +some data showing how it does indeed +scale at 0.1 Micron the gate delay is + + align:start position:0% +scale at 0.1 Micron the gate delay is + + + align:start position:0% +scale at 0.1 Micron the gate delay is +down in the five or so uh PC or some + + align:start position:0% +down in the five or so uh PC or some + + + align:start position:0% +down in the five or so uh PC or some +five peos second + + align:start position:0% +five peos second + + + align:start position:0% +five peos second +range well it turns out that the gate + + align:start position:0% +range well it turns out that the gate + + + align:start position:0% +range well it turns out that the gate +delay is inversely proportional to the + + align:start position:0% +delay is inversely proportional to the + + + align:start position:0% +delay is inversely proportional to the +current so if you can pump more current + + align:start position:0% +current so if you can pump more current + + + align:start position:0% +current so if you can pump more current +uh through each device then as one + + align:start position:0% +uh through each device then as one + + + align:start position:0% +uh through each device then as one +device charges the the device after it + + align:start position:0% +device charges the the device after it + + + align:start position:0% +device charges the the device after it +has to charge up a device the more + + align:start position:0% +has to charge up a device the more + + + align:start position:0% +has to charge up a device the more +current going through the more quickly + + align:start position:0% +current going through the more quickly + + + align:start position:0% +current going through the more quickly +it will charge its neighboring device so + + align:start position:0% +it will charge its neighboring device so + + + align:start position:0% +it will charge its neighboring device so +the name of the game and getting higher + + align:start position:0% +the name of the game and getting higher + + + align:start position:0% +the name of the game and getting higher +speed in logic devices at least for + + align:start position:0% +speed in logic devices at least for + + + align:start position:0% +speed in logic devices at least for +digital is at a given voltage to get + + align:start position:0% +digital is at a given voltage to get + + + align:start position:0% +digital is at a given voltage to get +more current more drain current out of + + align:start position:0% +more current more drain current out of + + + align:start position:0% +more current more drain current out of +the device and so you say okay let a + + align:start position:0% +the device and so you say okay let a + + + align:start position:0% +the device and so you say okay let a +give voltage how can I get more drain + + align:start position:0% +give voltage how can I get more drain + + + align:start position:0% +give voltage how can I get more drain +current well this is what the drain + + align:start position:0% +current well this is what the drain + + + align:start position:0% +current well this is what the drain +current looks like there are several uh + + align:start position:0% +current looks like there are several uh + + + align:start position:0% +current looks like there are several uh +physical variables it depends on it + + align:start position:0% +physical variables it depends on it + + + align:start position:0% +physical variables it depends on it +depends on the mobility of the carriers + + align:start position:0% +depends on the mobility of the carriers + + + align:start position:0% +depends on the mobility of the carriers +directly proportional it's inversely + + align:start position:0% +directly proportional it's inversely + + + align:start position:0% +directly proportional it's inversely +proportional to the oxide thickness so + + align:start position:0% +proportional to the oxide thickness so + + + align:start position:0% +proportional to the oxide thickness so +if I make the oxide thinner I get a + + align:start position:0% +if I make the oxide thinner I get a + + + align:start position:0% +if I make the oxide thinner I get a +higher capacitance and the current goes + + align:start position:0% +higher capacitance and the current goes + + + align:start position:0% +higher capacitance and the current goes +up that's why we're talking about gate + + align:start position:0% +up that's why we're talking about gate + + + align:start position:0% +up that's why we're talking about gate +dialectric scaling all the way down to + + align:start position:0% +dialectric scaling all the way down to + + + align:start position:0% +dialectric scaling all the way down to +below 10 angstroms um so that's that's + + align:start position:0% +below 10 angstroms um so that's that's + + + align:start position:0% +below 10 angstroms um so that's that's +where the gate dialectric scaling comes + + align:start position:0% +where the gate dialectric scaling comes + + + align:start position:0% +where the gate dialectric scaling comes +from and if I make the channel length + + align:start position:0% +from and if I make the channel length + + + align:start position:0% +from and if I make the channel length +shorter it does also go up so uh how how + + align:start position:0% +shorter it does also go up so uh how how + + + align:start position:0% +shorter it does also go up so uh how how +do people do conventional scaling to + + align:start position:0% +do people do conventional scaling to + + + align:start position:0% +do people do conventional scaling to +increase ID or speed for logic they they + + align:start position:0% +increase ID or speed for logic they they + + + align:start position:0% +increase ID or speed for logic they they +make the gate length shorter uh they + + align:start position:0% +make the gate length shorter uh they + + + align:start position:0% +make the gate length shorter uh they +reduce the gate oxide thickness the real + + align:start position:0% +reduce the gate oxide thickness the real + + + align:start position:0% +reduce the gate oxide thickness the real +question has been in the last five or 10 + + align:start position:0% +question has been in the last five or 10 + + + align:start position:0% +question has been in the last five or 10 +years what about the mobility is that a + + align:start position:0% +years what about the mobility is that a + + + align:start position:0% +years what about the mobility is that a +variable that we can tweak we're pretty + + align:start position:0% +variable that we can tweak we're pretty + + + align:start position:0% +variable that we can tweak we're pretty +much done with scaling theide because we + + align:start position:0% +much done with scaling theide because we + + + align:start position:0% +much done with scaling theide because we +can't get much thinner only a few atoms + + align:start position:0% +can't get much thinner only a few atoms + + + align:start position:0% +can't get much thinner only a few atoms +thick uh making the the transistor + + align:start position:0% +thick uh making the the transistor + + + align:start position:0% +thick uh making the the transistor +shorter is getting harder and harder log + + align:start position:0% +shorter is getting harder and harder log + + + align:start position:0% +shorter is getting harder and harder log +graphically and for electrostatic + + align:start position:0% +graphically and for electrostatic + + + align:start position:0% +graphically and for electrostatic +reasons don't have too many more + + align:start position:0% +reasons don't have too many more + + + align:start position:0% +reasons don't have too many more +variables in this equation so Mobility + + align:start position:0% +variables in this equation so Mobility + + + align:start position:0% +variables in this equation so Mobility +is the last thing to touch + + align:start position:0% + + + + align:start position:0% + +uh and that's where these silic and + + align:start position:0% +uh and that's where these silic and + + + align:start position:0% +uh and that's where these silic and +geranium Alloys come in here on page + + align:start position:0% +geranium Alloys come in here on page + + + align:start position:0% +geranium Alloys come in here on page +five uh what I'm showing is some data + + align:start position:0% +five uh what I'm showing is some data + + + align:start position:0% +five uh what I'm showing is some data +some classic data of a literature uh uh + + align:start position:0% +some classic data of a literature uh uh + + + align:start position:0% +some classic data of a literature uh uh +of what the electron Mobility that that + + align:start position:0% +of what the electron Mobility that that + + + align:start position:0% +of what the electron Mobility that that +that number mu is not a single number in + + align:start position:0% +that number mu is not a single number in + + + align:start position:0% +that number mu is not a single number in +a mosfet so this is a plot of the + + align:start position:0% +a mosfet so this is a plot of the + + + align:start position:0% +a mosfet so this is a plot of the +effective electron mobility in a channel + + align:start position:0% +effective electron mobility in a channel + + + align:start position:0% +effective electron mobility in a channel +and again as as this number goes up the + + align:start position:0% +and again as as this number goes up the + + + align:start position:0% +and again as as this number goes up the +current goes up at a given voltage as a + + align:start position:0% +current goes up at a given voltage as a + + + align:start position:0% +current goes up at a given voltage as a +function of the vertical field in the + + align:start position:0% +function of the vertical field in the + + + align:start position:0% +function of the vertical field in the +device the vertical field is induced by + + align:start position:0% +device the vertical field is induced by + + + align:start position:0% +device the vertical field is induced by +the gate so as I put a gate bias on uh + + align:start position:0% +the gate so as I put a gate bias on uh + + + align:start position:0% +the gate so as I put a gate bias on uh +the device as I bias the device uh the + + align:start position:0% +the device as I bias the device uh the + + + align:start position:0% +the device as I bias the device uh the +gate bias I get higher inversion charge + + align:start position:0% +gate bias I get higher inversion charge + + + align:start position:0% +gate bias I get higher inversion charge +density in fact the the mobility + + align:start position:0% +density in fact the the mobility + + + align:start position:0% +density in fact the the mobility +actually goes + + align:start position:0% +actually goes + + + align:start position:0% +actually goes +down uh but so you notice it's a + + align:start position:0% +down uh but so you notice it's a + + + align:start position:0% +down uh but so you notice it's a +function of the vertical effective field + + align:start position:0% +function of the vertical effective field + + + align:start position:0% +function of the vertical effective field +in the + + align:start position:0% +in the + + + align:start position:0% +in the +silicon and that modern mosfets are + + align:start position:0% +silicon and that modern mosfets are + + + align:start position:0% +silicon and that modern mosfets are +operating somewhere in this range right + + align:start position:0% +operating somewhere in this range right + + + align:start position:0% +operating somewhere in this range right +now I can just tell you based on the uh + + align:start position:0% +now I can just tell you based on the uh + + + align:start position:0% +now I can just tell you based on the uh +gate oxide thickness and the typical + + align:start position:0% +gate oxide thickness and the typical + + + align:start position:0% +gate oxide thickness and the typical +voltages one to three volts that you + + align:start position:0% +voltages one to three volts that you + + + align:start position:0% +voltages one to three volts that you +that that mosfets are operating in if + + align:start position:0% +that that mosfets are operating in if + + + align:start position:0% +that that mosfets are operating in if +you calculate it out the effective field + + align:start position:0% +you calculate it out the effective field + + + align:start position:0% +you calculate it out the effective field +in the channel is about a megga volt per + + align:start position:0% +in the channel is about a megga volt per + + + align:start position:0% +in the channel is about a megga volt per +centimeter so modern mosfets these days + + align:start position:0% +centimeter so modern mosfets these days + + + align:start position:0% +centimeter so modern mosfets these days +the electron Mobility is right about on + + align:start position:0% +the electron Mobility is right about on + + + align:start position:0% +the electron Mobility is right about on +this curve somewhere between 200 and 300 + + align:start position:0% +this curve somewhere between 200 and 300 + + + align:start position:0% +this curve somewhere between 200 and 300 +but closer to 200 a number of years ago + + align:start position:0% +but closer to 200 a number of years ago + + + align:start position:0% +but closer to 200 a number of years ago +when we Ed lighter doping so let's say + + align:start position:0% +when we Ed lighter doping so let's say + + + align:start position:0% +when we Ed lighter doping so let's say +you were using much lighter doping like + + align:start position:0% +you were using much lighter doping like + + + align:start position:0% +you were using much lighter doping like +317 and the oxides were thicker the + + align:start position:0% +317 and the oxides were thicker the + + + align:start position:0% +317 and the oxides were thicker the +vertical field was much lower maybe half + + align:start position:0% +vertical field was much lower maybe half + + + align:start position:0% +vertical field was much lower maybe half +a half of what it is today and the + + align:start position:0% +a half of what it is today and the + + + align:start position:0% +a half of what it is today and the +mobility was twice it was like 400 so + + align:start position:0% +mobility was twice it was like 400 so + + + align:start position:0% +mobility was twice it was like 400 so +this is the problem with Mobility as we + + align:start position:0% +this is the problem with Mobility as we + + + align:start position:0% +this is the problem with Mobility as we +March down the itrs we scale that gate + + align:start position:0% +March down the itrs we scale that gate + + + align:start position:0% +March down the itrs we scale that gate +oxide thickness so so we get higher + + align:start position:0% +oxide thickness so so we get higher + + + align:start position:0% +oxide thickness so so we get higher +capacitors that's good uh but we also + + align:start position:0% +capacitors that's good uh but we also + + + align:start position:0% +capacitors that's good uh but we also +increasing the doping in the channel and + + align:start position:0% +increasing the doping in the channel and + + + align:start position:0% +increasing the doping in the channel and +um we're increasing the vertical + + align:start position:0% +um we're increasing the vertical + + + align:start position:0% +um we're increasing the vertical +effective field so we're marching down + + align:start position:0% +effective field so we're marching down + + + align:start position:0% +effective field so we're marching down +this curve and the mobility is going + + align:start position:0% +this curve and the mobility is going + + + align:start position:0% +this curve and the mobility is going +lower and lower and lower with each + + align:start position:0% +lower and lower and lower with each + + + align:start position:0% +lower and lower and lower with each +generation that's bad that takes away + + align:start position:0% +generation that's bad that takes away + + + align:start position:0% +generation that's bad that takes away +from the our current drive to a certain + + align:start position:0% +from the our current drive to a certain + + + align:start position:0% +from the our current drive to a certain +extent um so so that's a problem so what + + align:start position:0% +extent um so so that's a problem so what + + + align:start position:0% +extent um so so that's a problem so what +people have decided to do is okay uh it + + align:start position:0% +people have decided to do is okay uh it + + + align:start position:0% +people have decided to do is okay uh it +turns out if I can change this Mobility + + align:start position:0% +turns out if I can change this Mobility + + + align:start position:0% +turns out if I can change this Mobility +curve in fact I can push the whole curve + + align:start position:0% +curve in fact I can push the whole curve + + + align:start position:0% +curve in fact I can push the whole curve +up quite significantly if I put stress + + align:start position:0% +up quite significantly if I put stress + + + align:start position:0% +up quite significantly if I put stress +on the Silicon + + align:start position:0% +on the Silicon + + + align:start position:0% +on the Silicon +and I'll say a little bit more in in in + + align:start position:0% +and I'll say a little bit more in in in + + + align:start position:0% +and I'll say a little bit more in in in +in the next few slides about how that + + align:start position:0% +in the next few slides about how that + + + align:start position:0% +in the next few slides about how that +works so people have tried a number of + + align:start position:0% +works so people have tried a number of + + + align:start position:0% +works so people have tried a number of +different ways to stress out the devices + + align:start position:0% +different ways to stress out the devices + + + align:start position:0% +different ways to stress out the devices +or to put stress on the Silicon you have + + align:start position:0% +or to put stress on the Silicon you have + + + align:start position:0% +or to put stress on the Silicon you have +to stress it in a certain way and this + + align:start position:0% +to stress it in a certain way and this + + + align:start position:0% +to stress it in a certain way and this +schematic kind of gives you an idea of a + + align:start position:0% +schematic kind of gives you an idea of a + + + align:start position:0% +schematic kind of gives you an idea of a +good way of inducing stress for + + align:start position:0% +good way of inducing stress for + + + align:start position:0% +good way of inducing stress for +electrons if you have a this looks like + + align:start position:0% +electrons if you have a this looks like + + + align:start position:0% +electrons if you have a this looks like +just like a regular n mosfet but you + + align:start position:0% +just like a regular n mosfet but you + + + align:start position:0% +just like a regular n mosfet but you +notice I've highlighted this uh Channel + + align:start position:0% +notice I've highlighted this uh Channel + + + align:start position:0% +notice I've highlighted this uh Channel +region in yellow uh it's called strain + + align:start position:0% +region in yellow uh it's called strain + + + align:start position:0% +region in yellow uh it's called strain +silicon uh classically strain silicon + + align:start position:0% +silicon uh classically strain silicon + + + align:start position:0% +silicon uh classically strain silicon +was generated by um taking taking a + + align:start position:0% +was generated by um taking taking a + + + align:start position:0% +was generated by um taking taking a +wafer of silicon geranium or a very + + align:start position:0% +wafer of silicon geranium or a very + + + align:start position:0% +wafer of silicon geranium or a very +thick layer of silic and geranium uh say + + align:start position:0% +thick layer of silic and geranium uh say + + + align:start position:0% +thick layer of silic and geranium uh say +with 30 or 20 or 30% geranium silicon + + align:start position:0% +with 30 or 20 or 30% geranium silicon + + + align:start position:0% +with 30 or 20 or 30% geranium silicon +geranium has a larger lce parameter than + + align:start position:0% +geranium has a larger lce parameter than + + + align:start position:0% +geranium has a larger lce parameter than +silicon pure geranium is about 4% bigger + + align:start position:0% +silicon pure geranium is about 4% bigger + + + align:start position:0% +silicon pure geranium is about 4% bigger +so this uh 30% layer um is going to be a + + align:start position:0% +so this uh 30% layer um is going to be a + + + align:start position:0% +so this uh 30% layer um is going to be a +little bit larger in its Lattis + + align:start position:0% +little bit larger in its Lattis + + + align:start position:0% +little bit larger in its Lattis +parameter so if it's relaxed it's bigger + + align:start position:0% +parameter so if it's relaxed it's bigger + + + align:start position:0% +parameter so if it's relaxed it's bigger +uh and and if the Silicon layer is thin + + align:start position:0% +uh and and if the Silicon layer is thin + + + align:start position:0% +uh and and if the Silicon layer is thin +when you grow it epot taxi the Silicon + + align:start position:0% +when you grow it epot taxi the Silicon + + + align:start position:0% +when you grow it epot taxi the Silicon +lce will actually stretch in the X and + + align:start position:0% +lce will actually stretch in the X and + + + align:start position:0% +lce will actually stretch in the X and +the Y directions to match that of the + + align:start position:0% +the Y directions to match that of the + + + align:start position:0% +the Y directions to match that of the +substrate as long as it's enough it's + + align:start position:0% +substrate as long as it's enough it's + + + align:start position:0% +substrate as long as it's enough it's +energetically favorable to stretch the + + align:start position:0% +energetically favorable to stretch the + + + align:start position:0% +energetically favorable to stretch the +bonds instead of instead of breaking + + align:start position:0% +bonds instead of instead of breaking + + + align:start position:0% +bonds instead of instead of breaking +them so this silicon is stretched it's + + align:start position:0% +them so this silicon is stretched it's + + + align:start position:0% +them so this silicon is stretched it's +last parameter in the X and Y plane is + + align:start position:0% +last parameter in the X and Y plane is + + + align:start position:0% +last parameter in the X and Y plane is +about 1 and a half% bigger than it would + + align:start position:0% +about 1 and a half% bigger than it would + + + align:start position:0% +about 1 and a half% bigger than it would +be in normal silicon that's a huge + + align:start position:0% +be in normal silicon that's a huge + + + align:start position:0% +be in normal silicon that's a huge +amount for to take a lattice a silic you + + align:start position:0% +amount for to take a lattice a silic you + + + align:start position:0% +amount for to take a lattice a silic you +know to take a crystal lce and stretch + + align:start position:0% +know to take a crystal lce and stretch + + + align:start position:0% +know to take a crystal lce and stretch +it by one and a half percent that's a + + align:start position:0% +it by one and a half percent that's a + + + align:start position:0% +it by one and a half percent that's a +lot uh as a result when you stretch it + + align:start position:0% +lot uh as a result when you stretch it + + + align:start position:0% +lot uh as a result when you stretch it +in the X and Y it actually compresses a + + align:start position:0% +in the X and Y it actually compresses a + + + align:start position:0% +in the X and Y it actually compresses a +little bit in Z so in fact we call this + + align:start position:0% +little bit in Z so in fact we call this + + + align:start position:0% +little bit in Z so in fact we call this +particular uh configuration uniform bi + + align:start position:0% +particular uh configuration uniform bi + + + align:start position:0% +particular uh configuration uniform bi +aial tensil stress it's bi axial because + + align:start position:0% +aial tensil stress it's bi axial because + + + align:start position:0% +aial tensil stress it's bi axial because +it's and it's tensil it's being uh + + align:start position:0% +it's and it's tensil it's being uh + + + align:start position:0% +it's and it's tensil it's being uh +pulled in X and Y so this is sort of the + + align:start position:0% +pulled in X and Y so this is sort of the + + + align:start position:0% +pulled in X and Y so this is sort of the +classic way that people have introduced + + align:start position:0% +classic way that people have introduced + + + align:start position:0% +classic way that people have introduced +strain and made MOS vets and they've + + align:start position:0% +strain and made MOS vets and they've + + + align:start position:0% +strain and made MOS vets and they've +looked at the mobility as a function of + + align:start position:0% +looked at the mobility as a function of + + + align:start position:0% +looked at the mobility as a function of +the amount of the strain there are other + + align:start position:0% +the amount of the strain there are other + + + align:start position:0% +the amount of the strain there are other +methods though for straining uh most of + + align:start position:0% +methods though for straining uh most of + + + align:start position:0% +methods though for straining uh most of +what I'll talk about in this lecture is + + align:start position:0% +what I'll talk about in this lecture is + + + align:start position:0% +what I'll talk about in this lecture is +this epitaxial growth method uh it's the + + align:start position:0% +this epitaxial growth method uh it's the + + + align:start position:0% +this epitaxial growth method uh it's the +easiest one to get a handle on the + + align:start position:0% +easiest one to get a handle on the + + + align:start position:0% +easiest one to get a handle on the +physics but there are other methods + + align:start position:0% +physics but there are other methods + + + align:start position:0% +physics but there are other methods +people have used for example you know + + align:start position:0% +people have used for example you know + + + align:start position:0% +people have used for example you know +when you make a mosset you don't just + + align:start position:0% +when you make a mosset you don't just + + + align:start position:0% +when you make a mosset you don't just +make an individual mosfet on a device + + align:start position:0% +make an individual mosfet on a device + + + align:start position:0% +make an individual mosfet on a device +all around the mosfet you know there's + + align:start position:0% +all around the mosfet you know there's + + + align:start position:0% +all around the mosfet you know there's +something we do something called trench + + align:start position:0% +something we do something called trench + + + align:start position:0% +something we do something called trench +isolation that we talked about in this + + align:start position:0% +isolation that we talked about in this + + + align:start position:0% +isolation that we talked about in this +course we dig out a trench on all the + + align:start position:0% +course we dig out a trench on all the + + + align:start position:0% +course we dig out a trench on all the +way around the moset and we fill it up + + align:start position:0% +way around the moset and we fill it up + + + align:start position:0% +way around the moset and we fill it up +with oxide or something some + + align:start position:0% +with oxide or something some + + + align:start position:0% +with oxide or something some +insulator well uh IBM show back in 97 + + align:start position:0% +insulator well uh IBM show back in 97 + + + align:start position:0% +insulator well uh IBM show back in 97 +depending on how you seal that up you + + align:start position:0% +depending on how you seal that up you + + + align:start position:0% +depending on how you seal that up you +can potentially induce stress either + + align:start position:0% +can potentially induce stress either + + + align:start position:0% +can potentially induce stress either +compressive or tensil depending on what + + align:start position:0% +compressive or tensil depending on what + + + align:start position:0% +compressive or tensil depending on what +material you put in uh because you're + + align:start position:0% +material you put in uh because you're + + + align:start position:0% +material you put in uh because you're +digging a moat around the device and + + align:start position:0% +digging a moat around the device and + + + align:start position:0% +digging a moat around the device and +you're putting some material in it so + + align:start position:0% +you're putting some material in it so + + + align:start position:0% +you're putting some material in it so +you can actually use the STI so-called + + align:start position:0% +you can actually use the STI so-called + + + align:start position:0% +you can actually use the STI so-called +to induce stress um there are other + + align:start position:0% +to induce stress um there are other + + + align:start position:0% +to induce stress um there are other +processes during fabrication uh that uh + + align:start position:0% +processes during fabrication uh that uh + + + align:start position:0% +processes during fabrication uh that uh +Intel is using now um where they + + align:start position:0% +Intel is using now um where they + + + align:start position:0% +Intel is using now um where they +actually dig out to source and drains + + align:start position:0% +actually dig out to source and drains + + + align:start position:0% +actually dig out to source and drains +they cut them out with Ed and they + + align:start position:0% +they cut them out with Ed and they + + + align:start position:0% +they cut them out with Ed and they +fill them back up with silicon geranium + + align:start position:0% +fill them back up with silicon geranium + + + align:start position:0% +fill them back up with silicon geranium +which compresses the channel which helps + + align:start position:0% +which compresses the channel which helps + + + align:start position:0% +which compresses the channel which helps +the whole Mobility so people are are + + align:start position:0% +the whole Mobility so people are are + + + align:start position:0% +the whole Mobility so people are are +doing things like that you can actually + + align:start position:0% +doing things like that you can actually + + + align:start position:0% +doing things like that you can actually +stress the device people take oh on top + + align:start position:0% +stress the device people take oh on top + + + align:start position:0% +stress the device people take oh on top +of the device they put a layer of high + + align:start position:0% +of the device they put a layer of high + + + align:start position:0% +of the device they put a layer of high +stress nitrite and try to induce stress + + align:start position:0% +stress nitrite and try to induce stress + + + align:start position:0% +stress nitrite and try to induce stress +by applying films that are high stress + + align:start position:0% +by applying films that are high stress + + + align:start position:0% +by applying films that are high stress +you can also bend the chip there's a + + align:start position:0% +you can also bend the chip there's a + + + align:start position:0% +you can also bend the chip there's a +small startup company um in the + + align:start position:0% +small startup company um in the + + + align:start position:0% +small startup company um in the +Southeast uh of unit states where + + align:start position:0% +Southeast uh of unit states where + + + align:start position:0% +Southeast uh of unit states where +they're taking chips thinning them and + + align:start position:0% +they're taking chips thinning them and + + + align:start position:0% +they're taking chips thinning them and +actually trying to pin mechanically to + + align:start position:0% +actually trying to pin mechanically to + + + align:start position:0% +actually trying to pin mechanically to +reduce stress it seems a little crazy + + align:start position:0% +reduce stress it seems a little crazy + + + align:start position:0% +reduce stress it seems a little crazy +but may be possible uh but this is + + align:start position:0% +but may be possible uh but this is + + + align:start position:0% +but may be possible uh but this is +epitaxial growth is in some ways the + + align:start position:0% +epitaxial growth is in some ways the + + + align:start position:0% +epitaxial growth is in some ways the +most well-rolled and the physics is a + + align:start position:0% +most well-rolled and the physics is a + + + align:start position:0% +most well-rolled and the physics is a +little bit easier to uh to get a handle + + align:start position:0% +little bit easier to uh to get a handle + + + align:start position:0% +little bit easier to uh to get a handle +on so but let me just mention here on + + align:start position:0% +on so but let me just mention here on + + + align:start position:0% +on so but let me just mention here on +slide seven this is the IBM work in + + align:start position:0% +slide seven this is the IBM work in + + + align:start position:0% +slide seven this is the IBM work in +1997 uh where they talked about if they + + align:start position:0% +1997 uh where they talked about if they + + + align:start position:0% +1997 uh where they talked about if they +in STI you know we' get learned in this + + align:start position:0% +in STI you know we' get learned in this + + + align:start position:0% +in STI you know we' get learned in this +course you fill up the shallow trench + + align:start position:0% +course you fill up the shallow trench + + + align:start position:0% +course you fill up the shallow trench +with with uh with first you oxidize the + + align:start position:0% +with with uh with first you oxidize the + + + align:start position:0% +with with uh with first you oxidize the +liner then you fill it up with lto or + + align:start position:0% +liner then you fill it up with lto or + + + align:start position:0% +liner then you fill it up with lto or +some low temperature oxide what they + + align:start position:0% +some low temperature oxide what they + + + align:start position:0% +some low temperature oxide what they +said was they grew uh an oxide liner for + + align:start position:0% +said was they grew uh an oxide liner for + + + align:start position:0% +said was they grew uh an oxide liner for +in for uh isolation then they filled the + + align:start position:0% +in for uh isolation then they filled the + + + align:start position:0% +in for uh isolation then they filled the +trench with poly poly + + align:start position:0% +trench with poly poly + + + align:start position:0% +trench with poly poly +silicon which they thought would induce + + align:start position:0% +silicon which they thought would induce + + + align:start position:0% +silicon which they thought would induce +a lot of a lot of stress compressive + + align:start position:0% +a lot of a lot of stress compressive + + + align:start position:0% +a lot of a lot of stress compressive +stress pushing in all around the edges + + align:start position:0% +stress pushing in all around the edges + + + align:start position:0% +stress pushing in all around the edges +of the device and then they looked at + + align:start position:0% +of the device and then they looked at + + + align:start position:0% +of the device and then they looked at +the whole Mobility uh and indeed what + + align:start position:0% +the whole Mobility uh and indeed what + + + align:start position:0% +the whole Mobility uh and indeed what +they found um particularly on SOI layers + + align:start position:0% +they found um particularly on SOI layers + + + align:start position:0% +they found um particularly on SOI layers +which are very thin uh when they made + + align:start position:0% +which are very thin uh when they made + + + align:start position:0% +which are very thin uh when they made +the device wi fa small say one micron + + align:start position:0% +the device wi fa small say one micron + + + align:start position:0% +the device wi fa small say one micron +compared to 10 Micron see make the + + align:start position:0% +compared to 10 Micron see make the + + + align:start position:0% +compared to 10 Micron see make the +device width small that brings the + + align:start position:0% +device width small that brings the + + + align:start position:0% +device width small that brings the +shallow trench in closer and closer to + + align:start position:0% +shallow trench in closer and closer to + + + align:start position:0% +shallow trench in closer and closer to +the center of the channel so we can have + + align:start position:0% +the center of the channel so we can have + + + align:start position:0% +the center of the channel so we can have +a bigger effect as it's pushing in and + + align:start position:0% +a bigger effect as it's pushing in and + + + align:start position:0% +a bigger effect as it's pushing in and +they saw that the whole Mobility went up + + align:start position:0% +they saw that the whole Mobility went up + + + align:start position:0% +they saw that the whole Mobility went up +quite a bit a 10 Micron device maybe the + + align:start position:0% +quite a bit a 10 Micron device maybe the + + + align:start position:0% +quite a bit a 10 Micron device maybe the +mobility was here about 100 or 110 and + + align:start position:0% +mobility was here about 100 or 110 and + + + align:start position:0% +mobility was here about 100 or 110 and +went up by about 34% to about 140 uh + + align:start position:0% +went up by about 34% to about 140 uh + + + align:start position:0% +went up by about 34% to about 140 uh +just by doing this now maybe it wasn't + + align:start position:0% +just by doing this now maybe it wasn't + + + align:start position:0% +just by doing this now maybe it wasn't +such a great idea to put that much + + align:start position:0% +such a great idea to put that much + + + align:start position:0% +such a great idea to put that much +stress and use polyc silic it wasn't + + align:start position:0% +stress and use polyc silic it wasn't + + + align:start position:0% +stress and use polyc silic it wasn't +necessarily a practical thing but it + + align:start position:0% +necessarily a practical thing but it + + + align:start position:0% +necessarily a practical thing but it +just kind of shows that you depending on + + align:start position:0% +just kind of shows that you depending on + + + align:start position:0% +just kind of shows that you depending on +how you do your processes how you do + + align:start position:0% +how you do your processes how you do + + + align:start position:0% +how you do your processes how you do +your STI can have a pretty big effect + + align:start position:0% +your STI can have a pretty big effect + + + align:start position:0% +your STI can have a pretty big effect +particularly on the whole + + align:start position:0% +particularly on the whole + + + align:start position:0% +particularly on the whole +Mobility um so this is was an indicator + + align:start position:0% +Mobility um so this is was an indicator + + + align:start position:0% +Mobility um so this is was an indicator +you early on that people need to pay + + align:start position:0% +you early on that people need to pay + + + align:start position:0% +you early on that people need to pay +dramatic attention to exactly what + + align:start position:0% +dramatic attention to exactly what + + + align:start position:0% +dramatic attention to exactly what +thermal budget you use what materials + + align:start position:0% +thermal budget you use what materials + + + align:start position:0% +thermal budget you use what materials +you use in STI in every layer you put on + + align:start position:0% +you use in STI in every layer you put on + + + align:start position:0% +you use in STI in every layer you put on +that device now that the devices are + + align:start position:0% +that device now that the devices are + + + align:start position:0% +that device now that the devices are +small the width of devices say is is + + align:start position:0% +small the width of devices say is is + + + align:start position:0% +small the width of devices say is is +less than a micron now that they're so + + align:start position:0% +less than a micron now that they're so + + + align:start position:0% +less than a micron now that they're so +small Edge effects can have a huge + + align:start position:0% +small Edge effects can have a huge + + + align:start position:0% +small Edge effects can have a huge +impact on the stress in the center of + + align:start position:0% +impact on the stress in the center of + + + align:start position:0% +impact on the stress in the center of +the channel and can end up impacting the + + align:start position:0% +the channel and can end up impacting the + + + align:start position:0% +the channel and can end up impacting the +mobility so I refer to the fact that we + + align:start position:0% +mobility so I refer to the fact that we + + + align:start position:0% +mobility so I refer to the fact that we +have the strain and I guess I should + + align:start position:0% +have the strain and I guess I should + + + align:start position:0% +have the strain and I guess I should +have introduced slide eight a little bit + + align:start position:0% +have introduced slide eight a little bit + + + align:start position:0% +have introduced slide eight a little bit +earlier but this just gives you uh a + + align:start position:0% +earlier but this just gives you uh a + + + align:start position:0% +earlier but this just gives you uh a +picture a ball and stick picture of what + + align:start position:0% +picture a ball and stick picture of what + + + align:start position:0% +picture a ball and stick picture of what +we're talking about so this ball and + + align:start position:0% +we're talking about so this ball and + + + align:start position:0% +we're talking about so this ball and +stick up in the upper left is meant to + + align:start position:0% +stick up in the upper left is meant to + + + align:start position:0% +stick up in the upper left is meant to +represent cubic silicon has a sort of + + align:start position:0% +represent cubic silicon has a sort of + + + align:start position:0% +represent cubic silicon has a sort of +you know it has a l parameter about 5.4 + + align:start position:0% +you know it has a l parameter about 5.4 + + + align:start position:0% +you know it has a l parameter about 5.4 +angstroms it's the diamond cubic + + align:start position:0% +angstroms it's the diamond cubic + + + align:start position:0% +angstroms it's the diamond cubic +structure but nevertheless it has a + + align:start position:0% +structure but nevertheless it has a + + + align:start position:0% +structure but nevertheless it has a +cubic uh symmetry to it X Y and Z in + + align:start position:0% +cubic uh symmetry to it X Y and Z in + + + align:start position:0% +cubic uh symmetry to it X Y and Z in +those three dimensions the lattice + + align:start position:0% +those three dimensions the lattice + + + align:start position:0% +those three dimensions the lattice +constant is parameter is the same + + align:start position:0% +constant is parameter is the same + + + align:start position:0% +constant is parameter is the same +number cubic geranium is larger same + + align:start position:0% +number cubic geranium is larger same + + + align:start position:0% +number cubic geranium is larger same +kind of diamond cubic structure but it's + + align:start position:0% +kind of diamond cubic structure but it's + + + align:start position:0% +kind of diamond cubic structure but it's +larger by about 4% if you make an alloy + + align:start position:0% +larger by about 4% if you make an alloy + + + align:start position:0% +larger by about 4% if you make an alloy +anywhere in between and you have it + + align:start position:0% +anywhere in between and you have it + + + align:start position:0% +anywhere in between and you have it +thick enough that it relaxes it'll have + + align:start position:0% +thick enough that it relaxes it'll have + + + align:start position:0% +thick enough that it relaxes it'll have +pretty much you can use a linear + + align:start position:0% +pretty much you can use a linear + + + align:start position:0% +pretty much you can use a linear +interpolation it's not quite perfect but + + align:start position:0% +interpolation it's not quite perfect but + + + align:start position:0% +interpolation it's not quite perfect but +you can use a linear interpolation uh so + + align:start position:0% +you can use a linear interpolation uh so + + + align:start position:0% +you can use a linear interpolation uh so +at 50% silic and geranium or 50% Gering + + align:start position:0% +at 50% silic and geranium or 50% Gering + + + align:start position:0% +at 50% silic and geranium or 50% Gering +the latest mismatch is about + + align:start position:0% +the latest mismatch is about + + + align:start position:0% +the latest mismatch is about +2% so there are two different types of + + align:start position:0% +2% so there are two different types of + + + align:start position:0% +2% so there are two different types of +silic geranium that people tend to talk + + align:start position:0% +silic geranium that people tend to talk + + + align:start position:0% +silic geranium that people tend to talk +about one is when you start with a + + align:start position:0% +about one is when you start with a + + + align:start position:0% +about one is when you start with a +silicon substrate and you grow a very + + align:start position:0% +silicon substrate and you grow a very + + + align:start position:0% +silicon substrate and you grow a very +thin layer say a few hundred angstrum of + + align:start position:0% +thin layer say a few hundred angstrum of + + + align:start position:0% +thin layer say a few hundred angstrum of +silicon geranium on Silicon what happens + + align:start position:0% +silicon geranium on Silicon what happens + + + align:start position:0% +silicon geranium on Silicon what happens +is you're taking this this this lattice + + align:start position:0% +is you're taking this this this lattice + + + align:start position:0% +is you're taking this this this lattice +here this cubic silicon geranium wants + + align:start position:0% +here this cubic silicon geranium wants + + + align:start position:0% +here this cubic silicon geranium wants +to be cubic uh it's larger it wants to + + align:start position:0% +to be cubic uh it's larger it wants to + + + align:start position:0% +to be cubic uh it's larger it wants to +be larger in equilibrium than silicon + + align:start position:0% +be larger in equilibrium than silicon + + + align:start position:0% +be larger in equilibrium than silicon +and you're squeezing it though it turns + + align:start position:0% +and you're squeezing it though it turns + + + align:start position:0% +and you're squeezing it though it turns +out again if the layer is thin enough + + align:start position:0% +out again if the layer is thin enough + + + align:start position:0% +out again if the layer is thin enough +it's energetically favorable for the + + align:start position:0% +it's energetically favorable for the + + + align:start position:0% +it's energetically favorable for the +inplane L parameter of this material + + align:start position:0% +inplane L parameter of this material + + + align:start position:0% +inplane L parameter of this material +that you're growing to match that of the + + align:start position:0% +that you're growing to match that of the + + + align:start position:0% +that you're growing to match that of the +substrate so the silicon geranium is + + align:start position:0% +substrate so the silicon geranium is + + + align:start position:0% +substrate so the silicon geranium is +kind of squeezed in X and Y and it + + align:start position:0% +kind of squeezed in X and Y and it + + + align:start position:0% +kind of squeezed in X and Y and it +pushes up in + + align:start position:0% +pushes up in + + + align:start position:0% +pushes up in +Z so this layer then is what we call a + + align:start position:0% +Z so this layer then is what we call a + + + align:start position:0% +Z so this layer then is what we call a +strain silicon germanium on relaxed + + align:start position:0% +strain silicon germanium on relaxed + + + align:start position:0% +strain silicon germanium on relaxed +silicon and it's under bi axial + + align:start position:0% +silicon and it's under bi axial + + + align:start position:0% +silicon and it's under bi axial +compression it's being compressed in the + + align:start position:0% +compression it's being compressed in the + + + align:start position:0% +compression it's being compressed in the +XY plane now if you make it thick enough + + align:start position:0% +XY plane now if you make it thick enough + + + align:start position:0% +XY plane now if you make it thick enough +eventually there's too much sored energy + + align:start position:0% +eventually there's too much sored energy + + + align:start position:0% +eventually there's too much sored energy +in those in those stretched bonds and + + align:start position:0% +in those in those stretched bonds and + + + align:start position:0% +in those in those stretched bonds and +the bonds will start breaking and get + + align:start position:0% +the bonds will start breaking and get + + + align:start position:0% +the bonds will start breaking and get +dislocations and it'll relax back to its + + align:start position:0% +dislocations and it'll relax back to its + + + align:start position:0% +dislocations and it'll relax back to its +cubic structure but for thin layers you + + align:start position:0% +cubic structure but for thin layers you + + + align:start position:0% +cubic structure but for thin layers you +can achieve this sort of pseudomorphic + + align:start position:0% +can achieve this sort of pseudomorphic + + + align:start position:0% +can achieve this sort of pseudomorphic +uh structure you can also do kind of the + + align:start position:0% +uh structure you can also do kind of the + + + align:start position:0% +uh structure you can also do kind of the +opposite or the upside down experiment + + align:start position:0% +opposite or the upside down experiment + + + align:start position:0% +opposite or the upside down experiment +you take a wafer of silicon geranium + + align:start position:0% +you take a wafer of silicon geranium + + + align:start position:0% +you take a wafer of silicon geranium +that's very thick that's already relaxed + + align:start position:0% +that's very thick that's already relaxed + + + align:start position:0% +that's very thick that's already relaxed +that has a larger lattice parameter and + + align:start position:0% +that has a larger lattice parameter and + + + align:start position:0% +that has a larger lattice parameter and +I try to stick silicon on it in in in + + align:start position:0% +I try to stick silicon on it in in in + + + align:start position:0% +I try to stick silicon on it in in in +epitaxial growth again if the silicon's + + align:start position:0% +epitaxial growth again if the silicon's + + + align:start position:0% +epitaxial growth again if the silicon's +thin enough it will now stretch in X and + + align:start position:0% +thin enough it will now stretch in X and + + + align:start position:0% +thin enough it will now stretch in X and +Y to match the last parameter of the + + align:start position:0% +Y to match the last parameter of the + + + align:start position:0% +Y to match the last parameter of the +substrate and it will compress in see so + + align:start position:0% +substrate and it will compress in see so + + + align:start position:0% +substrate and it will compress in see so +we call this silicon layer EP layer as + + align:start position:0% +we call this silicon layer EP layer as + + + align:start position:0% +we call this silicon layer EP layer as +being in bi axial tension and again if + + align:start position:0% +being in bi axial tension and again if + + + align:start position:0% +being in bi axial tension and again if +you grow it too large the bogs will no + + align:start position:0% +you grow it too large the bogs will no + + + align:start position:0% +you grow it too large the bogs will no +longer stretch they'll break you'll get + + align:start position:0% +longer stretch they'll break you'll get + + + align:start position:0% +longer stretch they'll break you'll get +dislocations so it can go back instead + + align:start position:0% +dislocations so it can go back instead + + + align:start position:0% +dislocations so it can go back instead +of being stretched it to go back to its + + align:start position:0% +of being stretched it to go back to its + + + align:start position:0% +of being stretched it to go back to its +normaliz parameter that point it be + + align:start position:0% +normaliz parameter that point it be + + + align:start position:0% +normaliz parameter that point it be +relaxed so these this is the type of + + align:start position:0% +relaxed so these this is the type of + + + align:start position:0% +relaxed so these this is the type of +material you'll see a lot in fets and + + align:start position:0% +material you'll see a lot in fets and + + + align:start position:0% +material you'll see a lot in fets and +you see this material in in bipolar + + align:start position:0% +you see this material in in bipolar + + + align:start position:0% +you see this material in in bipolar +transistors and some P channel + + align:start position:0% + + + + align:start position:0% + +mosfets so um what what are some of the + + align:start position:0% +mosfets so um what what are some of the + + + align:start position:0% +mosfets so um what what are some of the +important properties of of this strain I + + align:start position:0% +important properties of of this strain I + + + align:start position:0% +important properties of of this strain I +already mentioned to you for mosfets + + align:start position:0% +already mentioned to you for mosfets + + + align:start position:0% +already mentioned to you for mosfets +when you start stretching the Silicon + + align:start position:0% +when you start stretching the Silicon + + + align:start position:0% +when you start stretching the Silicon +lattice parameter or compressing the + + align:start position:0% +lattice parameter or compressing the + + + align:start position:0% +lattice parameter or compressing the +parameter uh you can improve the + + align:start position:0% +parameter uh you can improve the + + + align:start position:0% +parameter uh you can improve the +mobility but there are other parameters + + align:start position:0% +mobility but there are other parameters + + + align:start position:0% +mobility but there are other parameters +that you change when you introduce + + align:start position:0% +that you change when you introduce + + + align:start position:0% +that you change when you introduce +strain when you put silic and geranium + + align:start position:0% +strain when you put silic and geranium + + + align:start position:0% +strain when you put silic and geranium +in probably one of the most important + + align:start position:0% +in probably one of the most important + + + align:start position:0% +in probably one of the most important +parameters uh you you need to know about + + align:start position:0% +parameters uh you you need to know about + + + align:start position:0% +parameters uh you you need to know about +is the + + align:start position:0% +is the + + + align:start position:0% +is the +bandap so uh there is an energy band Gap + + align:start position:0% +bandap so uh there is an energy band Gap + + + align:start position:0% +bandap so uh there is an energy band Gap +difference between silicon and silicon + + align:start position:0% +difference between silicon and silicon + + + align:start position:0% +difference between silicon and silicon +geranium if this represents the band gap + + align:start position:0% +geranium if this represents the band gap + + + align:start position:0% +geranium if this represents the band gap +of relaxed silicon so EC is the + + align:start position:0% +of relaxed silicon so EC is the + + + align:start position:0% +of relaxed silicon so EC is the +conduction band EV is the veilance band + + align:start position:0% +conduction band EV is the veilance band + + + align:start position:0% +conduction band EV is the veilance band +this is the band gap of strain silicon + + align:start position:0% +this is the band gap of strain silicon + + + align:start position:0% +this is the band gap of strain silicon +geranium you see it's much smaller and + + align:start position:0% +geranium you see it's much smaller and + + + align:start position:0% +geranium you see it's much smaller and +most of the difference occurs in the + + align:start position:0% +most of the difference occurs in the + + + align:start position:0% +most of the difference occurs in the +veence band the veence band energy is is + + align:start position:0% +veence band the veence band energy is is + + + align:start position:0% +veence band the veence band energy is is +is larger so silic geranium has a + + align:start position:0% +is larger so silic geranium has a + + + align:start position:0% +is larger so silic geranium has a +smaller band Gap how much small smaller + + align:start position:0% +smaller band Gap how much small smaller + + + align:start position:0% +smaller band Gap how much small smaller +well you can look on this curve this is + + align:start position:0% +well you can look on this curve this is + + + align:start position:0% +well you can look on this curve this is +the difference between the band gap of + + align:start position:0% +the difference between the band gap of + + + align:start position:0% +the difference between the band gap of +the two as a function of germanium + + align:start position:0% +the two as a function of germanium + + + align:start position:0% +the two as a function of germanium +content so here if I have strain silicon + + align:start position:0% +content so here if I have strain silicon + + + align:start position:0% +content so here if I have strain silicon +geranium you should use this upper curve + + align:start position:0% +geranium you should use this upper curve + + + align:start position:0% +geranium you should use this upper curve +not the one that says unstrained so at + + align:start position:0% +not the one that says unstrained so at + + + align:start position:0% +not the one that says unstrained so at +20% the band Gap shrinks by about 150 + + align:start position:0% +20% the band Gap shrinks by about 150 + + + align:start position:0% +20% the band Gap shrinks by about 150 +molts roughly so and you can read that + + align:start position:0% +molts roughly so and you can read that + + + align:start position:0% +molts roughly so and you can read that +right off the curve here at 50% it's + + align:start position:0% +right off the curve here at 50% it's + + + align:start position:0% +right off the curve here at 50% it's +another number maybe 350 so you have an + + align:start position:0% +another number maybe 350 so you have an + + + align:start position:0% +another number maybe 350 so you have an +idea uh of how it moves all these data + + align:start position:0% +idea uh of how it moves all these data + + + align:start position:0% +idea uh of how it moves all these data +points are are data from the literature + + align:start position:0% +points are are data from the literature + + + align:start position:0% +points are are data from the literature +that people extracted the bandap by + + align:start position:0% +that people extracted the bandap by + + + align:start position:0% +that people extracted the bandap by +various devices dood bipolar transistors + + align:start position:0% +various devices dood bipolar transistors + + + align:start position:0% +various devices dood bipolar transistors +for do and the the solid line is some + + align:start position:0% +for do and the the solid line is some + + + align:start position:0% +for do and the the solid line is some +theory that was published a long time + + align:start position:0% +theory that was published a long time + + + align:start position:0% +theory that was published a long time +ago so uh now the other thing that's if + + align:start position:0% +ago so uh now the other thing that's if + + + align:start position:0% +ago so uh now the other thing that's if +it's strained if it's unstrained if you + + align:start position:0% +it's strained if it's unstrained if you + + + align:start position:0% +it's strained if it's unstrained if you +grow the Silicon geranium so thick that + + align:start position:0% +grow the Silicon geranium so thick that + + + align:start position:0% +grow the Silicon geranium so thick that +it relaxes back so it comes comes back + + align:start position:0% +it relaxes back so it comes comes back + + + align:start position:0% +it relaxes back so it comes comes back +to be this cubic structure then what + + align:start position:0% +to be this cubic structure then what + + + align:start position:0% +to be this cubic structure then what +happens to the band Gap well in fact the + + align:start position:0% +happens to the band Gap well in fact the + + + align:start position:0% +happens to the band Gap well in fact the +band Gap difference is a lot smaller + + align:start position:0% +band Gap difference is a lot smaller + + + align:start position:0% +band Gap difference is a lot smaller +when it's unstrained the band Gap + + align:start position:0% +when it's unstrained the band Gap + + + align:start position:0% +when it's unstrained the band Gap +difference say at 20% is only about 100 + + align:start position:0% +difference say at 20% is only about 100 + + + align:start position:0% +difference say at 20% is only about 100 +molts so a big fraction of this band Gap + + align:start position:0% +molts so a big fraction of this band Gap + + + align:start position:0% +molts so a big fraction of this band Gap +offset this band Gap difference is due + + align:start position:0% +offset this band Gap difference is due + + + align:start position:0% +offset this band Gap difference is due +to the strain it's due to the lce + + align:start position:0% +to the strain it's due to the lce + + + align:start position:0% +to the strain it's due to the lce +parameter change uh a certain fraction + + align:start position:0% +parameter change uh a certain fraction + + + align:start position:0% +parameter change uh a certain fraction +is due to the fact that we're just + + align:start position:0% +is due to the fact that we're just + + + align:start position:0% +is due to the fact that we're just +adding + + align:start position:0% +adding + + + align:start position:0% +adding +germanium um so so you need to know + + align:start position:0% +germanium um so so you need to know + + + align:start position:0% +germanium um so so you need to know +whether the material is unstrained or + + align:start position:0% +whether the material is unstrained or + + + align:start position:0% +whether the material is unstrained or +strained or somewhere in between in + + align:start position:0% +strained or somewhere in between in + + + align:start position:0% +strained or somewhere in between in +order to figure out what the band + + align:start position:0% +order to figure out what the band + + + align:start position:0% +order to figure out what the band +structure looks + + align:start position:0% +structure looks + + + align:start position:0% +structure looks +like and in fact on slide 10 I don't + + align:start position:0% +like and in fact on slide 10 I don't + + + align:start position:0% +like and in fact on slide 10 I don't +have to go through this in great detail + + align:start position:0% +have to go through this in great detail + + + align:start position:0% +have to go through this in great detail +if you haven't had energy Band Theory + + align:start position:0% +if you haven't had energy Band Theory + + + align:start position:0% +if you haven't had energy Band Theory +it's a little tricky but slide 10 gives + + align:start position:0% +it's a little tricky but slide 10 gives + + + align:start position:0% +it's a little tricky but slide 10 gives +you an idea of how the strain does + + align:start position:0% +you an idea of how the strain does + + + align:start position:0% +you an idea of how the strain does +affect the ener bands and the lineup and + + align:start position:0% +affect the ener bands and the lineup and + + + align:start position:0% +affect the ener bands and the lineup and +in fact uh if we look at the case for + + align:start position:0% +in fact uh if we look at the case for + + + align:start position:0% +in fact uh if we look at the case for +strained silicon geranium on Silicon uh + + align:start position:0% +strained silicon geranium on Silicon uh + + + align:start position:0% +strained silicon geranium on Silicon uh +so it'll be remember we said it when we + + align:start position:0% +so it'll be remember we said it when we + + + align:start position:0% +so it'll be remember we said it when we +grow strain silicon geranium is under bi + + align:start position:0% +grow strain silicon geranium is under bi + + + align:start position:0% +grow strain silicon geranium is under bi +axial compression in the X and and Y + + align:start position:0% +axial compression in the X and and Y + + + align:start position:0% +axial compression in the X and and Y +planes being compressed strain silicon + + align:start position:0% +planes being compressed strain silicon + + + align:start position:0% +planes being compressed strain silicon +geranium on silk in the band lineup + + align:start position:0% +geranium on silk in the band lineup + + + align:start position:0% +geranium on silk in the band lineup +looks like this as I mentioned most of + + align:start position:0% +looks like this as I mentioned most of + + + align:start position:0% +looks like this as I mentioned most of +the band offset is in the valance band + + align:start position:0% +the band offset is in the valance band + + + align:start position:0% +the band offset is in the valance band +so the holes will tend to be comined in + + align:start position:0% +so the holes will tend to be comined in + + + align:start position:0% +so the holes will tend to be comined in +the Silicon geranium uh there's very + + align:start position:0% +the Silicon geranium uh there's very + + + align:start position:0% +the Silicon geranium uh there's very +little band offset uh the lowest energy + + align:start position:0% +little band offset uh the lowest energy + + + align:start position:0% +little band offset uh the lowest energy +conduction band is about aligned in + + align:start position:0% +conduction band is about aligned in + + + align:start position:0% +conduction band is about aligned in +strain silicon geranium versus uh versus + + align:start position:0% +strain silicon geranium versus uh versus + + + align:start position:0% +strain silicon geranium versus uh versus +cubic silicon so there's not much + + align:start position:0% +cubic silicon so there's not much + + + align:start position:0% +cubic silicon so there's not much +opportunity for confining electrons so + + align:start position:0% +opportunity for confining electrons so + + + align:start position:0% +opportunity for confining electrons so +this material it turns out is ideal for + + align:start position:0% +this material it turns out is ideal for + + + align:start position:0% +this material it turns out is ideal for +a heter junction bipolar transistor for + + align:start position:0% +a heter junction bipolar transistor for + + + align:start position:0% +a heter junction bipolar transistor for +an npn this material has been in + + align:start position:0% +an npn this material has been in + + + align:start position:0% +an npn this material has been in +production for about 10 years people use + + align:start position:0% +production for about 10 years people use + + + align:start position:0% +production for about 10 years people use +it uh in high-speed RF + + align:start position:0% +it uh in high-speed RF + + + align:start position:0% +it uh in high-speed RF +devices uh so that's kind of a well a + + align:start position:0% +devices uh so that's kind of a well a + + + align:start position:0% +devices uh so that's kind of a well a +more well characterized and well-known + + align:start position:0% +more well characterized and well-known + + + align:start position:0% +more well characterized and well-known +structure where where the Germania + + align:start position:0% +structure where where the Germania + + + align:start position:0% +structure where where the Germania +fraction in a typical hbt you would buy + + align:start position:0% +fraction in a typical hbt you would buy + + + align:start position:0% +fraction in a typical hbt you would buy +off the shelf right now is probably + + align:start position:0% +off the shelf right now is probably + + + align:start position:0% +off the shelf right now is probably +about between 10% and 20% % of the atoms + + align:start position:0% +about between 10% and 20% % of the atoms + + + align:start position:0% +about between 10% and 20% % of the atoms +will be germanium in an + + align:start position:0% +will be germanium in an + + + align:start position:0% +will be germanium in an +hbt on the other hand if you grow the + + align:start position:0% +hbt on the other hand if you grow the + + + align:start position:0% +hbt on the other hand if you grow the +opposite structure so you have relaxed + + align:start position:0% +opposite structure so you have relaxed + + + align:start position:0% +opposite structure so you have relaxed +silicon germanium substrate and you grow + + align:start position:0% +silicon germanium substrate and you grow + + + align:start position:0% +silicon germanium substrate and you grow +a thin layer of silic and remember we + + align:start position:0% +a thin layer of silic and remember we + + + align:start position:0% +a thin layer of silic and remember we +said this was by axial tension the band + + align:start position:0% +said this was by axial tension the band + + + align:start position:0% +said this was by axial tension the band +lineup is quite different in fact you do + + align:start position:0% +lineup is quite different in fact you do + + + align:start position:0% +lineup is quite different in fact you do +get a sizable difference in the + + align:start position:0% +get a sizable difference in the + + + align:start position:0% +get a sizable difference in the +conduction band uh position and in fact + + align:start position:0% +conduction band uh position and in fact + + + align:start position:0% +conduction band uh position and in fact +uh the conduction band is lower the + + align:start position:0% +uh the conduction band is lower the + + + align:start position:0% +uh the conduction band is lower the +energy is lower in strain silicon so the + + align:start position:0% +energy is lower in strain silicon so the + + + align:start position:0% +energy is lower in strain silicon so the +electrons will tend to go into the + + align:start position:0% +electrons will tend to go into the + + + align:start position:0% +electrons will tend to go into the +strain silicon layer so if you make a + + align:start position:0% +strain silicon layer so if you make a + + + align:start position:0% +strain silicon layer so if you make a +fet and you make this as your the + + align:start position:0% +fet and you make this as your the + + + align:start position:0% +fet and you make this as your the +electrons want to go into the strain + + align:start position:0% +electrons want to go into the strain + + + align:start position:0% +electrons want to go into the strain +silicon the holes want to be in the + + align:start position:0% +silicon the holes want to be in the + + + align:start position:0% +silicon the holes want to be in the +Silicon geranium side um so this is + + align:start position:0% +Silicon geranium side um so this is + + + align:start position:0% +Silicon geranium side um so this is +what's called a tight two band alignment + + align:start position:0% +what's called a tight two band alignment + + + align:start position:0% +what's called a tight two band alignment +so you can make lots of interesting + + align:start position:0% +so you can make lots of interesting + + + align:start position:0% +so you can make lots of interesting +devices uh just by taking silic silicon + + align:start position:0% +devices uh just by taking silic silicon + + + align:start position:0% +devices uh just by taking silic silicon +and and straining it on on relaxed + + align:start position:0% +and and straining it on on relaxed + + + align:start position:0% +and and straining it on on relaxed +silicon + + align:start position:0% + + + + align:start position:0% + +geranium the other thing that happens + + align:start position:0% +geranium the other thing that happens + + + align:start position:0% +geranium the other thing that happens +here that's important and we'll talk + + align:start position:0% +here that's important and we'll talk + + + align:start position:0% +here that's important and we'll talk +about when we talk about the mobility + + align:start position:0% +about when we talk about the mobility + + + align:start position:0% +about when we talk about the mobility +enhancement you notice what's happened + + align:start position:0% +enhancement you notice what's happened + + + align:start position:0% +enhancement you notice what's happened +is the conduction band is actually split + + align:start position:0% +is the conduction band is actually split + + + align:start position:0% +is the conduction band is actually split +into two levels originally uh there was + + align:start position:0% +into two levels originally uh there was + + + align:start position:0% +into two levels originally uh there was +only a single uh energy level and that + + align:start position:0% +only a single uh energy level and that + + + align:start position:0% +only a single uh energy level and that +splitting is what truly was responsible + + align:start position:0% +splitting is what truly was responsible + + + align:start position:0% +splitting is what truly was responsible +uh to a large extent for the mobility + + align:start position:0% +uh to a large extent for the mobility + + + align:start position:0% +uh to a large extent for the mobility +Improvement if you really wanted to get + + align:start position:0% +Improvement if you really wanted to get + + + align:start position:0% +Improvement if you really wanted to get +nitty-gritty I won't go through it but + + align:start position:0% +nitty-gritty I won't go through it but + + + align:start position:0% +nitty-gritty I won't go through it but +here on page 11 I've made a reference to + + align:start position:0% +here on page 11 I've made a reference to + + + align:start position:0% +here on page 11 I've made a reference to +a famous paper by Chris vanderwal and + + align:start position:0% +a famous paper by Chris vanderwal and + + + align:start position:0% +a famous paper by Chris vanderwal and +Richard Martin published in the mid + + align:start position:0% +Richard Martin published in the mid + + + align:start position:0% +Richard Martin published in the mid +1980s vanderwall and Martin actually + + align:start position:0% +1980s vanderwall and Martin actually + + + align:start position:0% +1980s vanderwall and Martin actually +theoretically did did a pretty good job + + align:start position:0% +theoretically did did a pretty good job + + + align:start position:0% +theoretically did did a pretty good job +uh of of trying to calculate what the + + align:start position:0% +uh of of trying to calculate what the + + + align:start position:0% +uh of of trying to calculate what the +energy band structure looks like for + + align:start position:0% +energy band structure looks like for + + + align:start position:0% +energy band structure looks like for +strain silicon geranium on cubic silicon + + align:start position:0% +strain silicon geranium on cubic silicon + + + align:start position:0% +strain silicon geranium on cubic silicon +which is we're showing over here and + + align:start position:0% +which is we're showing over here and + + + align:start position:0% +which is we're showing over here and +also for strain silicon geranium on + + align:start position:0% +also for strain silicon geranium on + + + align:start position:0% +also for strain silicon geranium on +cubic geranium so but they have both of + + align:start position:0% +cubic geranium so but they have both of + + + align:start position:0% +cubic geranium so but they have both of +these and and uh I won't go through it + + align:start position:0% +these and and uh I won't go through it + + + align:start position:0% +these and and uh I won't go through it +in any great detail but I if you're + + align:start position:0% +in any great detail but I if you're + + + align:start position:0% +in any great detail but I if you're +interested in the solid state physics + + align:start position:0% +interested in the solid state physics + + + align:start position:0% +interested in the solid state physics +and you end up working in this area this + + align:start position:0% +and you end up working in this area this + + + align:start position:0% +and you end up working in this area this +is a good paper for you to look at um + + align:start position:0% +is a good paper for you to look at um + + + align:start position:0% +is a good paper for you to look at um +again the band Gap would be the + + align:start position:0% +again the band Gap would be the + + + align:start position:0% +again the band Gap would be the +difference uh the the distance between + + align:start position:0% +difference uh the the distance between + + + align:start position:0% +difference uh the the distance between +this point here in the conduction band + + align:start position:0% +this point here in the conduction band + + + align:start position:0% +this point here in the conduction band +and a point here in the veence band so + + align:start position:0% +and a point here in the veence band so + + + align:start position:0% +and a point here in the veence band so +but they actually calculated how the + + align:start position:0% +but they actually calculated how the + + + align:start position:0% +but they actually calculated how the +veence and conduction bands move as you + + align:start position:0% +veence and conduction bands move as you + + + align:start position:0% +veence and conduction bands move as you +add strain and geranium to the + + align:start position:0% +add strain and geranium to the + + + align:start position:0% +add strain and geranium to the +system on slide 12 on also giving you uh + + align:start position:0% +system on slide 12 on also giving you uh + + + align:start position:0% +system on slide 12 on also giving you uh +excuse me a reference for how not only + + align:start position:0% +excuse me a reference for how not only + + + align:start position:0% +excuse me a reference for how not only +has the band Gap changes but people have + + align:start position:0% +has the band Gap changes but people have + + + align:start position:0% +has the band Gap changes but people have +actually made some reference some + + align:start position:0% +actually made some reference some + + + align:start position:0% +actually made some reference some +measurements of the energy band offsets + + align:start position:0% +measurements of the energy band offsets + + + align:start position:0% +measurements of the energy band offsets +when you have strained silicon on + + align:start position:0% +when you have strained silicon on + + + align:start position:0% +when you have strained silicon on +relaxed silicon geranium say for a + + align:start position:0% +relaxed silicon geranium say for a + + + align:start position:0% +relaxed silicon geranium say for a +mosfet this is taken out of Jeff welzer + + align:start position:0% +mosfet this is taken out of Jeff welzer + + + align:start position:0% +mosfet this is taken out of Jeff welzer +thesis from 1994 and and what what you + + align:start position:0% +thesis from 1994 and and what what you + + + align:start position:0% +thesis from 1994 and and what what you +can see here this is the basic structure + + align:start position:0% +can see here this is the basic structure + + + align:start position:0% +can see here this is the basic structure +you have an an oxide you have a thin + + align:start position:0% +you have an an oxide you have a thin + + + align:start position:0% +you have an an oxide you have a thin +layer of strained silicon and you have + + align:start position:0% +layer of strained silicon and you have + + + align:start position:0% +layer of strained silicon and you have +these energy offsets here the energy + + align:start position:0% +these energy offsets here the energy + + + align:start position:0% +these energy offsets here the energy +conduction band energy is a little lower + + align:start position:0% +conduction band energy is a little lower + + + align:start position:0% +conduction band energy is a little lower +and the veence band energy is uh is a + + align:start position:0% +and the veence band energy is uh is a + + + align:start position:0% +and the veence band energy is uh is a +slightly different in strain silicon and + + align:start position:0% +slightly different in strain silicon and + + + align:start position:0% +slightly different in strain silicon and +these numbers Delta EC how different + + align:start position:0% +these numbers Delta EC how different + + + align:start position:0% +these numbers Delta EC how different +they are these these these energy band + + align:start position:0% +they are these these these energy band + + + align:start position:0% +they are these these these energy band +discontinuities were actually measured + + align:start position:0% +discontinuities were actually measured + + + align:start position:0% +discontinuities were actually measured +and Delta EV here as a function of the + + align:start position:0% +and Delta EV here as a function of the + + + align:start position:0% +and Delta EV here as a function of the +geranium fraction in the + + align:start position:0% +geranium fraction in the + + + align:start position:0% +geranium fraction in the +substrate uh the bullets are the + + align:start position:0% +substrate uh the bullets are the + + + align:start position:0% +substrate uh the bullets are the +measurements and the lines are are the + + align:start position:0% +measurements and the lines are are the + + + align:start position:0% +measurements and the lines are are the +uh are the calculations from fand wall + + align:start position:0% +uh are the calculations from fand wall + + + align:start position:0% +uh are the calculations from fand wall +and Martin and indeed you get pretty + + align:start position:0% +and Martin and indeed you get pretty + + + align:start position:0% +and Martin and indeed you get pretty +good agreement so we have a rough idea + + align:start position:0% +good agreement so we have a rough idea + + + align:start position:0% +good agreement so we have a rough idea +now of what these energy band structures + + align:start position:0% +now of what these energy band structures + + + align:start position:0% +now of what these energy band structures +look like when I add strain or when I + + align:start position:0% +look like when I add strain or when I + + + align:start position:0% +look like when I add strain or when I +add uh you know silicon geranium to to + + align:start position:0% +add uh you know silicon geranium to to + + + align:start position:0% +add uh you know silicon geranium to to +the substrate um so that's important for + + align:start position:0% +the substrate um so that's important for + + + align:start position:0% +the substrate um so that's important for +figuring out how all these devices + + align:start position:0% + + + + align:start position:0% + +work I mentioned that um when you + + align:start position:0% +work I mentioned that um when you + + + align:start position:0% +work I mentioned that um when you +squeeze silicon either you stretch it uh + + align:start position:0% +squeeze silicon either you stretch it uh + + + align:start position:0% +squeeze silicon either you stretch it uh +in a bi axial sense um you can improve + + align:start position:0% +in a bi axial sense um you can improve + + + align:start position:0% +in a bi axial sense um you can improve +the mobility and the question is well + + align:start position:0% +the mobility and the question is well + + + align:start position:0% +the mobility and the question is well +why is that I don't want to go into + + align:start position:0% +why is that I don't want to go into + + + align:start position:0% +why is that I don't want to go into +detail in the solid state physics but it + + align:start position:0% +detail in the solid state physics but it + + + align:start position:0% +detail in the solid state physics but it +turns out if you put silicon in bi axial + + align:start position:0% +turns out if you put silicon in bi axial + + + align:start position:0% +turns out if you put silicon in bi axial +tension you break the cubic symmetry of + + align:start position:0% +tension you break the cubic symmetry of + + + align:start position:0% +tension you break the cubic symmetry of +the lattice ordinarily in the lattice + + align:start position:0% +the lattice ordinarily in the lattice + + + align:start position:0% +the lattice ordinarily in the lattice +the X YZ directions are all completely + + align:start position:0% +the X YZ directions are all completely + + + align:start position:0% +the X YZ directions are all completely +symmetric when when silicon is not + + align:start position:0% +symmetric when when silicon is not + + + align:start position:0% +symmetric when when silicon is not +strained when it's strained they + + align:start position:0% +strained when it's strained they + + + align:start position:0% +strained when it's strained they +actually become asymmetric um X and Y + + align:start position:0% +actually become asymmetric um X and Y + + + align:start position:0% +actually become asymmetric um X and Y +last parameters larger than in the Z and + + align:start position:0% +last parameters larger than in the Z and + + + align:start position:0% +last parameters larger than in the Z and +what happens by that breaking of the + + align:start position:0% +what happens by that breaking of the + + + align:start position:0% +what happens by that breaking of the +physical symmetry um is that that um the + + align:start position:0% +physical symmetry um is that that um the + + + align:start position:0% +physical symmetry um is that that um the +six energy of ellipsoids uh ellipsoids + + align:start position:0% +six energy of ellipsoids uh ellipsoids + + + align:start position:0% +six energy of ellipsoids uh ellipsoids +in in constant energy space that are all + + align:start position:0% +in in constant energy space that are all + + + align:start position:0% +in in constant energy space that are all +at the same energy actually split up + + align:start position:0% +at the same energy actually split up + + + align:start position:0% +at the same energy actually split up +when you introduce the strain and two of + + align:start position:0% +when you introduce the strain and two of + + + align:start position:0% +when you introduce the strain and two of +them these two ellipsoids here where the + + align:start position:0% +them these two ellipsoids here where the + + + align:start position:0% +them these two ellipsoids here where the +electrons can be these two uh red ones + + align:start position:0% +electrons can be these two uh red ones + + + align:start position:0% +electrons can be these two uh red ones +the so-called perpendicular valleys + + align:start position:0% +the so-called perpendicular valleys + + + align:start position:0% +the so-called perpendicular valleys +labeled del2 they actually end up being + + align:start position:0% +labeled del2 they actually end up being + + + align:start position:0% +labeled del2 they actually end up being +at a lower energy than these other four + + align:start position:0% +at a lower energy than these other four + + + align:start position:0% +at a lower energy than these other four +so we get this we get this strain + + align:start position:0% +so we get this we get this strain + + + align:start position:0% +so we get this we get this strain +induced splitting uh in bulk silicon all + + align:start position:0% +induced splitting uh in bulk silicon all + + + align:start position:0% +induced splitting uh in bulk silicon all +six of these valleys that that represent + + align:start position:0% +six of these valleys that that represent + + + align:start position:0% +six of these valleys that that represent +states that electrons can occupy all six + + align:start position:0% +states that electrons can occupy all six + + + align:start position:0% +states that electrons can occupy all six +of them are at the same energy level but + + align:start position:0% +of them are at the same energy level but + + + align:start position:0% +of them are at the same energy level but +by group Theory when we break the + + align:start position:0% +by group Theory when we break the + + + align:start position:0% +by group Theory when we break the +Symmetry we break that up into a + + align:start position:0% +Symmetry we break that up into a + + + align:start position:0% +Symmetry we break that up into a +two-fold degenerate uh level which is + + align:start position:0% +two-fold degenerate uh level which is + + + align:start position:0% +two-fold degenerate uh level which is +lower energy and a four-fold degenerate + + align:start position:0% +lower energy and a four-fold degenerate + + + align:start position:0% +lower energy and a four-fold degenerate +level so by breaking this up actually + + align:start position:0% +level so by breaking this up actually + + + align:start position:0% +level so by breaking this up actually +what happens is now most of electrons + + align:start position:0% +what happens is now most of electrons + + + align:start position:0% +what happens is now most of electrons +want to be in these red valleys and the + + align:start position:0% +want to be in these red valleys and the + + + align:start position:0% +want to be in these red valleys and the +scattering between the red and the green + + align:start position:0% +scattering between the red and the green + + + align:start position:0% +scattering between the red and the green +is suppressed because it costs you + + align:start position:0% +is suppressed because it costs you + + + align:start position:0% +is suppressed because it costs you +energy so instead of scattering between + + align:start position:0% +energy so instead of scattering between + + + align:start position:0% +energy so instead of scattering between +all six you can only scatter you know + + align:start position:0% +all six you can only scatter you know + + + align:start position:0% +all six you can only scatter you know +very effectively between these two red + + align:start position:0% +very effectively between these two red + + + align:start position:0% +very effectively between these two red +ones and so the scattering time goes up + + align:start position:0% +ones and so the scattering time goes up + + + align:start position:0% +ones and so the scattering time goes up +and the mobility is directly + + align:start position:0% +and the mobility is directly + + + align:start position:0% +and the mobility is directly +proportional to the scattering time the + + align:start position:0% +proportional to the scattering time the + + + align:start position:0% +proportional to the scattering time the +inplane uh ma uh effective Mass also + + align:start position:0% +inplane uh ma uh effective Mass also + + + align:start position:0% +inplane uh ma uh effective Mass also +goes down so the mobility also goes up + + align:start position:0% +goes down so the mobility also goes up + + + align:start position:0% +goes down so the mobility also goes up +for that reason so just by breaking the + + align:start position:0% +for that reason so just by breaking the + + + align:start position:0% +for that reason so just by breaking the +Symmetry we can change the occupation of + + align:start position:0% +Symmetry we can change the occupation of + + + align:start position:0% +Symmetry we can change the occupation of +the energy bands in Silicon and we can + + align:start position:0% +the energy bands in Silicon and we can + + + align:start position:0% +the energy bands in Silicon and we can +make the mobility higher for electrons + + align:start position:0% +make the mobility higher for electrons + + + align:start position:0% +make the mobility higher for electrons +um in the veence band I'm not going to + + align:start position:0% +um in the veence band I'm not going to + + + align:start position:0% +um in the veence band I'm not going to +go through in great detail but it's it's + + align:start position:0% +go through in great detail but it's it's + + + align:start position:0% +go through in great detail but it's it's +quite a bit more complicated but the + + align:start position:0% +quite a bit more complicated but the + + + align:start position:0% +quite a bit more complicated but the +turn out with strin we also split the + + align:start position:0% +turn out with strin we also split the + + + align:start position:0% +turn out with strin we also split the +genery in the veence band we also + + align:start position:0% +genery in the veence band we also + + + align:start position:0% +genery in the veence band we also +suppress interband scattering it it is a + + align:start position:0% +suppress interband scattering it it is a + + + align:start position:0% +suppress interband scattering it it is a +lot more tricky but uh it is possible to + + align:start position:0% +lot more tricky but uh it is possible to + + + align:start position:0% +lot more tricky but uh it is possible to +also induced uh in improved uh hole + + align:start position:0% +also induced uh in improved uh hole + + + align:start position:0% +also induced uh in improved uh hole +Mobility or pimos Mobility uh by + + align:start position:0% +Mobility or pimos Mobility uh by + + + align:start position:0% +Mobility or pimos Mobility uh by +introducing + + align:start position:0% +introducing + + + align:start position:0% +introducing +strain and in fact here on slide 14 I'll + + align:start position:0% +strain and in fact here on slide 14 I'll + + + align:start position:0% +strain and in fact here on slide 14 I'll +just walk through some of the older data + + align:start position:0% +just walk through some of the older data + + + align:start position:0% +just walk through some of the older data +this was from 1992 by welser these were + + align:start position:0% +this was from 1992 by welser these were + + + align:start position:0% +this was from 1992 by welser these were +the first strain mosfets that were + + align:start position:0% +the first strain mosfets that were + + + align:start position:0% +the first strain mosfets that were +fabricated where uh he made a thin layer + + align:start position:0% +fabricated where uh he made a thin layer + + + align:start position:0% +fabricated where uh he made a thin layer +of strained silicon on relaxed silicon + + align:start position:0% +of strained silicon on relaxed silicon + + + align:start position:0% +of strained silicon on relaxed silicon +Germania and then just implanted it and + + align:start position:0% +Germania and then just implanted it and + + + align:start position:0% +Germania and then just implanted it and +made it made a silicon mosfet with a + + align:start position:0% +made it made a silicon mosfet with a + + + align:start position:0% +made it made a silicon mosfet with a +source and drain was an N mosfet and + + align:start position:0% +source and drain was an N mosfet and + + + align:start position:0% +source and drain was an N mosfet and +this he called the surface Channel + + align:start position:0% +this he called the surface Channel + + + align:start position:0% +this he called the surface Channel +mosfet because the bands aligned so that + + align:start position:0% +mosfet because the bands aligned so that + + + align:start position:0% +mosfet because the bands aligned so that +the electrons wanted to be at the + + align:start position:0% +the electrons wanted to be at the + + + align:start position:0% +the electrons wanted to be at the +surface so the channel is at the surface + + align:start position:0% +surface so the channel is at the surface + + + align:start position:0% +surface so the channel is at the surface +this he called a bur Channel mosfet so + + align:start position:0% +this he called a bur Channel mosfet so + + + align:start position:0% +this he called a bur Channel mosfet so +if you look at the energy band diagram + + align:start position:0% +if you look at the energy band diagram + + + align:start position:0% +if you look at the energy band diagram +here there's a little bit of silicon + + align:start position:0% +here there's a little bit of silicon + + + align:start position:0% +here there's a little bit of silicon +geranium on top and that confines the + + align:start position:0% +geranium on top and that confines the + + + align:start position:0% +geranium on top and that confines the +electrons to be a little bit buried + + align:start position:0% +electrons to be a little bit buried + + + align:start position:0% +electrons to be a little bit buried +below the surface it's like a moss bet + + align:start position:0% +below the surface it's like a moss bet + + + align:start position:0% +below the surface it's like a moss bet +but where the channel is slightly + + align:start position:0% +but where the channel is slightly + + + align:start position:0% +but where the channel is slightly +buried and on on 15 actually measured + + align:start position:0% +buried and on on 15 actually measured + + + align:start position:0% +buried and on on 15 actually measured +some of those mobilities these were the + + align:start position:0% +some of those mobilities these were the + + + align:start position:0% +some of those mobilities these were the +first mobilities measured and if you + + align:start position:0% +first mobilities measured and if you + + + align:start position:0% +first mobilities measured and if you +look at this solid line This is the + + align:start position:0% +look at this solid line This is the + + + align:start position:0% +look at this solid line This is the +mobility measured in a moset that had no + + align:start position:0% +mobility measured in a moset that had no + + + align:start position:0% +mobility measured in a moset that had no +strain and for a surface channel moset + + align:start position:0% +strain and for a surface channel moset + + + align:start position:0% +strain and for a surface channel moset +the mobility that he measured was about + + align:start position:0% +the mobility that he measured was about + + + align:start position:0% +the mobility that he measured was about +um oh I don't know 80% higher about a + + align:start position:0% +um oh I don't know 80% higher about a + + + align:start position:0% +um oh I don't know 80% higher about a +factor of 1.8 Improvement in the surface + + align:start position:0% +factor of 1.8 Improvement in the surface + + + align:start position:0% +factor of 1.8 Improvement in the surface +channel so right off the bat as a + + align:start position:0% +channel so right off the bat as a + + + align:start position:0% +channel so right off the bat as a +function of vertical field you see we + + align:start position:0% +function of vertical field you see we + + + align:start position:0% +function of vertical field you see we +have parameter by changing the strain + + align:start position:0% +have parameter by changing the strain + + + align:start position:0% +have parameter by changing the strain +you can up the mobility by about 80% if + + align:start position:0% +you can up the mobility by about 80% if + + + align:start position:0% +you can up the mobility by about 80% if +you do the berry Channel you can get + + align:start position:0% +you do the berry Channel you can get + + + align:start position:0% +you do the berry Channel you can get +even higher mobilities at at low gate + + align:start position:0% +even higher mobilities at at low gate + + + align:start position:0% +even higher mobilities at at low gate +bias but the mobility seem to go down U + + align:start position:0% +bias but the mobility seem to go down U + + + align:start position:0% +bias but the mobility seem to go down U +at High Gate bias uh for various reasons + + align:start position:0% +at High Gate bias uh for various reasons + + + align:start position:0% +at High Gate bias uh for various reasons +so kind of the the first evidence that + + align:start position:0% +so kind of the the first evidence that + + + align:start position:0% +so kind of the the first evidence that +strain makes a big + + align:start position:0% +strain makes a big + + + align:start position:0% +strain makes a big +difference these are the actual + + align:start position:0% +difference these are the actual + + + align:start position:0% +difference these are the actual +structures that one can grow shown on on + + align:start position:0% +structures that one can grow shown on on + + + align:start position:0% +structures that one can grow shown on on +on slide 16 uh again to make an inoss F + + align:start position:0% +on slide 16 uh again to make an inoss F + + + align:start position:0% +on slide 16 uh again to make an inoss F +you can grow relax silicon geranium with + + align:start position:0% +you can grow relax silicon geranium with + + + align:start position:0% +you can grow relax silicon geranium with +a thin layer of strain silicon and this + + align:start position:0% +a thin layer of strain silicon and this + + + align:start position:0% +a thin layer of strain silicon and this +becomes a high electron Mobility channel + + align:start position:0% +becomes a high electron Mobility channel + + + align:start position:0% +becomes a high electron Mobility channel +it's slightly different structure is + + align:start position:0% +it's slightly different structure is + + + align:start position:0% +it's slightly different structure is +needed for the P Moss very similar but + + align:start position:0% +needed for the P Moss very similar but + + + align:start position:0% +needed for the P Moss very similar but +but with slight variations uh so you can + + align:start position:0% +but with slight variations uh so you can + + + align:start position:0% +but with slight variations uh so you can +make seos uh devices using this type of + + align:start position:0% +make seos uh devices using this type of + + + align:start position:0% +make seos uh devices using this type of +technique and I'll skip through the + + align:start position:0% +technique and I'll skip through the + + + align:start position:0% +technique and I'll skip through the +energy band diagrams for + + align:start position:0% +energy band diagrams for + + + align:start position:0% +energy band diagrams for +now um slide 17 shows some Metrology the + + align:start position:0% +now um slide 17 shows some Metrology the + + + align:start position:0% +now um slide 17 shows some Metrology the +question you may be thinking well how do + + align:start position:0% +question you may be thinking well how do + + + align:start position:0% +question you may be thinking well how do +you really know all right your Mobility + + align:start position:0% +you really know all right your Mobility + + + align:start position:0% +you really know all right your Mobility +went up but how do you really know them + + align:start position:0% +went up but how do you really know them + + + align:start position:0% +went up but how do you really know them +that the layers are strained especially + + align:start position:0% +that the layers are strained especially + + + align:start position:0% +that the layers are strained especially +when they're so thin how do you measure + + align:start position:0% +when they're so thin how do you measure + + + align:start position:0% +when they're so thin how do you measure +strain in a layer that's only 100 Anum + + align:start position:0% +strain in a layer that's only 100 Anum + + + align:start position:0% +strain in a layer that's only 100 Anum +thick you really can't use x-ray + + align:start position:0% +thick you really can't use x-ray + + + align:start position:0% +thick you really can't use x-ray +defraction x-ray defraction on 100 + + align:start position:0% +defraction x-ray defraction on 100 + + + align:start position:0% +defraction x-ray defraction on 100 +anstrom layer going to be really tough + + align:start position:0% +anstrom layer going to be really tough + + + align:start position:0% +anstrom layer going to be really tough +because the layer is very thin so how do + + align:start position:0% +because the layer is very thin so how do + + + align:start position:0% +because the layer is very thin so how do +you measure that reduced that change in + + align:start position:0% +you measure that reduced that change in + + + align:start position:0% +you measure that reduced that change in +the last parameter well it turns out + + align:start position:0% +the last parameter well it turns out + + + align:start position:0% +the last parameter well it turns out +there's a technique called Raman + + align:start position:0% +there's a technique called Raman + + + align:start position:0% +there's a technique called Raman +scattering which is an optical + + align:start position:0% +scattering which is an optical + + + align:start position:0% +scattering which is an optical +interaction there are certain + + align:start position:0% +interaction there are certain + + + align:start position:0% +interaction there are certain +vibrational modes in a lattice that will + + align:start position:0% +vibrational modes in a lattice that will + + + align:start position:0% +vibrational modes in a lattice that will +scatter uh uh scatter photons and the + + align:start position:0% +scatter uh uh scatter photons and the + + + align:start position:0% +scatter uh uh scatter photons and the +ramen effect can be used to measure the + + align:start position:0% +ramen effect can be used to measure the + + + align:start position:0% +ramen effect can be used to measure the +strain or the change in mass parameter + + align:start position:0% +strain or the change in mass parameter + + + align:start position:0% +strain or the change in mass parameter +even a very very thin layer so here's an + + align:start position:0% +even a very very thin layer so here's an + + + align:start position:0% +even a very very thin layer so here's an +example of a mosfet that was made uh a + + align:start position:0% +example of a mosfet that was made uh a + + + align:start position:0% +example of a mosfet that was made uh a +Ramen Spectrum so you're measuring the + + align:start position:0% +Ramen Spectrum so you're measuring the + + + align:start position:0% +Ramen Spectrum so you're measuring the +intensity of the scattered light uh as a + + align:start position:0% +intensity of the scattered light uh as a + + + align:start position:0% +intensity of the scattered light uh as a +f of the + + align:start position:0% +f of the + + + align:start position:0% +f of the +frequency uh in inverse centimeters and + + align:start position:0% +frequency uh in inverse centimeters and + + + align:start position:0% +frequency uh in inverse centimeters and +um there's you see a large Peak here + + align:start position:0% +um there's you see a large Peak here + + + align:start position:0% +um there's you see a large Peak here +associated with relaxed silicon geranium + + align:start position:0% +associated with relaxed silicon geranium + + + align:start position:0% +associated with relaxed silicon geranium +and there's a small Peak here which is + + align:start position:0% +and there's a small Peak here which is + + + align:start position:0% +and there's a small Peak here which is +the thin strained silicon layer now if + + align:start position:0% +the thin strained silicon layer now if + + + align:start position:0% +the thin strained silicon layer now if +that layer were + + align:start position:0% +that layer were + + + align:start position:0% +that layer were +unstrained bulk silicon if you just take + + align:start position:0% +unstrained bulk silicon if you just take + + + align:start position:0% +unstrained bulk silicon if you just take +a wafer of bulk silicon and subject to + + align:start position:0% +a wafer of bulk silicon and subject to + + + align:start position:0% +a wafer of bulk silicon and subject to +Rama scattering you get a line at 521 in + + align:start position:0% +Rama scattering you get a line at 521 in + + + align:start position:0% +Rama scattering you get a line at 521 in +centimeters so it turns out the shift of + + align:start position:0% +centimeters so it turns out the shift of + + + align:start position:0% +centimeters so it turns out the shift of +the sil of the Silicon strain silicon + + align:start position:0% +the sil of the Silicon strain silicon + + + align:start position:0% +the sil of the Silicon strain silicon +Peak the shift between between that Peak + + align:start position:0% +Peak the shift between between that Peak + + + align:start position:0% +Peak the shift between between that Peak +and 521 is a measure of the amount of + + align:start position:0% +and 521 is a measure of the amount of + + + align:start position:0% +and 521 is a measure of the amount of +strength so this is a very nice way you + + align:start position:0% +strength so this is a very nice way you + + + align:start position:0% +strength so this is a very nice way you +can oxidize a wafer strip the oxide a + + align:start position:0% +can oxidize a wafer strip the oxide a + + + align:start position:0% +can oxidize a wafer strip the oxide a +strain silicon you can see if the strain + + align:start position:0% +strain silicon you can see if the strain + + + align:start position:0% +strain silicon you can see if the strain +is still there in fact you can figure + + align:start position:0% +is still there in fact you can figure + + + align:start position:0% +is still there in fact you can figure +out um uh your the relaxed silicon + + align:start position:0% +out um uh your the relaxed silicon + + + align:start position:0% +out um uh your the relaxed silicon +germanium content as well using this so + + align:start position:0% +germanium content as well using this so + + + align:start position:0% +germanium content as well using this so +uh slide 18 just shows you some + + align:start position:0% +uh slide 18 just shows you some + + + align:start position:0% +uh slide 18 just shows you some +measurements that people have made the + + align:start position:0% +measurements that people have made the + + + align:start position:0% +measurements that people have made the +ramen Peak + + align:start position:0% +ramen Peak + + + align:start position:0% +ramen Peak +shift in uh the frequency shift in + + align:start position:0% +shift in uh the frequency shift in + + + align:start position:0% +shift in uh the frequency shift in +inverse centimeter as a function of uh + + align:start position:0% +inverse centimeter as a function of uh + + + align:start position:0% +inverse centimeter as a function of uh +the amount of germanium fraction of the + + align:start position:0% +the amount of germanium fraction of the + + + align:start position:0% +the amount of germanium fraction of the +substrate for strained silicon layers + + align:start position:0% +substrate for strained silicon layers + + + align:start position:0% +substrate for strained silicon layers +you can see it's there's a theoretical + + align:start position:0% +you can see it's there's a theoretical + + + align:start position:0% +you can see it's there's a theoretical +line here and this is some uh the + + align:start position:0% +line here and this is some uh the + + + align:start position:0% +line here and this is some uh the +bullets represent measured points so um + + align:start position:0% +bullets represent measured points so um + + + align:start position:0% +bullets represent measured points so um +using Ramen if you have uh uh you have + + align:start position:0% +using Ramen if you have uh uh you have + + + align:start position:0% +using Ramen if you have uh uh you have +the right kind of ramen set up you can + + align:start position:0% +the right kind of ramen set up you can + + + align:start position:0% +the right kind of ramen set up you can +actually uh get a peak shift so for 20% + + align:start position:0% +actually uh get a peak shift so for 20% + + + align:start position:0% +actually uh get a peak shift so for 20% +geranium here we expect a Ramen Peak + + align:start position:0% +geranium here we expect a Ramen Peak + + + align:start position:0% +geranium here we expect a Ramen Peak +shift of about six uh six to seven uh + + align:start position:0% +shift of about six uh six to seven uh + + + align:start position:0% +shift of about six uh six to seven uh +inverse centimeters that gives you an + + align:start position:0% +inverse centimeters that gives you an + + + align:start position:0% +inverse centimeters that gives you an +idea of uh how you can measure the + + align:start position:0% +idea of uh how you can measure the + + + align:start position:0% +idea of uh how you can measure the +strain in the in the + + align:start position:0% +strain in the in the + + + align:start position:0% +strain in the in the +material slide 19 shows you a material + + align:start position:0% +material slide 19 shows you a material + + + align:start position:0% +material slide 19 shows you a material +that's been oxidized you might be where + + align:start position:0% +that's been oxidized you might be where + + + align:start position:0% +that's been oxidized you might be where +thinking okay fine you can grow these + + align:start position:0% +thinking okay fine you can grow these + + + align:start position:0% +thinking okay fine you can grow these +epitaxial layers they'll be strained + + align:start position:0% +epitaxial layers they'll be strained + + + align:start position:0% +epitaxial layers they'll be strained +what happens if you oxidize the Silicon + + align:start position:0% +what happens if you oxidize the Silicon + + + align:start position:0% +what happens if you oxidize the Silicon +is it going to somehow Relax The Strain + + align:start position:0% +is it going to somehow Relax The Strain + + + align:start position:0% +is it going to somehow Relax The Strain +because of that oxidation process and + + align:start position:0% +because of that oxidation process and + + + align:start position:0% +because of that oxidation process and +the breaking of bonds in the oxidation + + align:start position:0% +the breaking of bonds in the oxidation + + + align:start position:0% +the breaking of bonds in the oxidation +well it turns out it doesn't in fact uh + + align:start position:0% +well it turns out it doesn't in fact uh + + + align:start position:0% +well it turns out it doesn't in fact uh +the as grown Ramen Spectrum here uh this + + align:start position:0% +the as grown Ramen Spectrum here uh this + + + align:start position:0% +the as grown Ramen Spectrum here uh this +is for the epitaxial layer as it was + + align:start position:0% +is for the epitaxial layer as it was + + + align:start position:0% +is for the epitaxial layer as it was +first Grown you do get a strain silicon + + align:start position:0% +first Grown you do get a strain silicon + + + align:start position:0% +first Grown you do get a strain silicon +Peak right here near to 510 if you + + align:start position:0% +Peak right here near to 510 if you + + + align:start position:0% +Peak right here near to 510 if you +oxidize it at 850 for 10 minutes you + + align:start position:0% +oxidize it at 850 for 10 minutes you + + + align:start position:0% +oxidize it at 850 for 10 minutes you +still get that strain silicon peak in + + align:start position:0% +still get that strain silicon peak in + + + align:start position:0% +still get that strain silicon peak in +although the peak is smaller height + + align:start position:0% +although the peak is smaller height + + + align:start position:0% +although the peak is smaller height +because of course the layer is thinner + + align:start position:0% +because of course the layer is thinner + + + align:start position:0% +because of course the layer is thinner +when you oxidize you consume silicon but + + align:start position:0% +when you oxidize you consume silicon but + + + align:start position:0% +when you oxidize you consume silicon but +the the peak position it remains at 510 + + align:start position:0% +the the peak position it remains at 510 + + + align:start position:0% +the the peak position it remains at 510 +it remains at the same point and this + + align:start position:0% +it remains at the same point and this + + + align:start position:0% +it remains at the same point and this +has been verified very many times and of + + align:start position:0% +has been verified very many times and of + + + align:start position:0% +has been verified very many times and of +course in the mosque that you do see the + + align:start position:0% +course in the mosque that you do see the + + + align:start position:0% +course in the mosque that you do see the +enhanced Mobility so there doesn't seem + + align:start position:0% +enhanced Mobility so there doesn't seem + + + align:start position:0% +enhanced Mobility so there doesn't seem +to be any significant strain relaxation + + align:start position:0% +to be any significant strain relaxation + + + align:start position:0% +to be any significant strain relaxation +at least when you oxidize in these type + + align:start position:0% +at least when you oxidize in these type + + + align:start position:0% +at least when you oxidize in these type +of temperatures you're to go up to a + + align:start position:0% +of temperatures you're to go up to a + + + align:start position:0% +of temperatures you're to go up to a +thousand or more then you could start + + align:start position:0% +thousand or more then you could start + + + align:start position:0% +thousand or more then you could start +running into trouble uh when the + + align:start position:0% +running into trouble uh when the + + + align:start position:0% +running into trouble uh when the +geranium starts uh diffusing around + + align:start position:0% + + + + align:start position:0% + +so on slide 20 I'm just sort of + + align:start position:0% +so on slide 20 I'm just sort of + + + align:start position:0% +so on slide 20 I'm just sort of +reviewing for you giving you an idea of + + align:start position:0% +reviewing for you giving you an idea of + + + align:start position:0% +reviewing for you giving you an idea of +some of the early measurements people + + align:start position:0% +some of the early measurements people + + + align:start position:0% +some of the early measurements people +made of how the mobility was enhanced + + align:start position:0% +made of how the mobility was enhanced + + + align:start position:0% +made of how the mobility was enhanced +and the left side is for n mosfets and + + align:start position:0% +and the left side is for n mosfets and + + + align:start position:0% +and the left side is for n mosfets and +you see these this black line This dash + + align:start position:0% +you see these this black line This dash + + + align:start position:0% +you see these this black line This dash +line is for control devices and these + + align:start position:0% +line is for control devices and these + + + align:start position:0% +line is for control devices and these +other lines on top are for 10% geranium + + align:start position:0% +other lines on top are for 10% geranium + + + align:start position:0% +other lines on top are for 10% geranium +in the substrate 20 and 30 you see as + + align:start position:0% +in the substrate 20 and 30 you see as + + + align:start position:0% +in the substrate 20 and 30 you see as +you add more geranium in the substrate + + align:start position:0% +you add more geranium in the substrate + + + align:start position:0% +you add more geranium in the substrate +the whole the electron Mobility curve + + align:start position:0% +the whole the electron Mobility curve + + + align:start position:0% +the whole the electron Mobility curve +all moves up and you get a nice + + align:start position:0% +all moves up and you get a nice + + + align:start position:0% +all moves up and you get a nice +enhancement + + align:start position:0% +enhancement + + + align:start position:0% +enhancement +uh on holes for for the for pmosfets uh + + align:start position:0% +uh on holes for for the for pmosfets uh + + + align:start position:0% +uh on holes for for the for pmosfets uh +there was some enhancement measured + + align:start position:0% +there was some enhancement measured + + + align:start position:0% +there was some enhancement measured +although the enhancement is diminished + + align:start position:0% +although the enhancement is diminished + + + align:start position:0% +although the enhancement is diminished +you see that the enhancement factor is + + align:start position:0% +you see that the enhancement factor is + + + align:start position:0% +you see that the enhancement factor is +actually going down as you go to higher + + align:start position:0% +actually going down as you go to higher + + + align:start position:0% +actually going down as you go to higher +vertical Fields here so that that's + + align:start position:0% +vertical Fields here so that that's + + + align:start position:0% +vertical Fields here so that that's +becomes that's a higher vertical Fields + + align:start position:0% +becomes that's a higher vertical Fields + + + align:start position:0% +becomes that's a higher vertical Fields +is where a lot of modern mosfets operate + + align:start position:0% +is where a lot of modern mosfets operate + + + align:start position:0% +is where a lot of modern mosfets operate +so that's a bit of an issue uh for P + + align:start position:0% +so that's a bit of an issue uh for P + + + align:start position:0% +so that's a bit of an issue uh for P +mosfets for using this + + align:start position:0% +mosfets for using this + + + align:start position:0% +mosfets for using this +technique those are research devices + + align:start position:0% +technique those are research devices + + + align:start position:0% +technique those are research devices +this on slide 21 is some more recent + + align:start position:0% +this on slide 21 is some more recent + + + align:start position:0% +this on slide 21 is some more recent +Publications in a Manu manufacturing + + align:start position:0% +Publications in a Manu manufacturing + + + align:start position:0% +Publications in a Manu manufacturing +style process although it's not in + + align:start position:0% +style process although it's not in + + + align:start position:0% +style process although it's not in +manufacturing the process was a full + + align:start position:0% +manufacturing the process was a full + + + align:start position:0% +manufacturing the process was a full +manufacturing style process that IBM did + + align:start position:0% +manufacturing style process that IBM did + + + align:start position:0% +manufacturing style process that IBM did +it had all the attributes of a real + + align:start position:0% +it had all the attributes of a real + + + align:start position:0% +it had all the attributes of a real +manufactured device it had shallow + + align:start position:0% +manufactured device it had shallow + + + align:start position:0% +manufactured device it had shallow +trench isolation had um it had well uh + + align:start position:0% +trench isolation had um it had well uh + + + align:start position:0% +trench isolation had um it had well uh +implants Halo implants raised Source + + align:start position:0% +implants Halo implants raised Source + + + align:start position:0% +implants Halo implants raised Source +drain by Epi uh and a thin gate oxide so + + align:start position:0% +drain by Epi uh and a thin gate oxide so + + + align:start position:0% +drain by Epi uh and a thin gate oxide so +this is a real uh real device as opposed + + align:start position:0% +this is a real uh real device as opposed + + + align:start position:0% +this is a real uh real device as opposed +to the university style and again you + + align:start position:0% +to the university style and again you + + + align:start position:0% +to the university style and again you +can see the mobility for electrons goes + + align:start position:0% +can see the mobility for electrons goes + + + align:start position:0% +can see the mobility for electrons goes +up with strain about 100% Improvement + + align:start position:0% +up with strain about 100% Improvement + + + align:start position:0% +up with strain about 100% Improvement +that is a factor of two s there is an + + align:start position:0% +that is a factor of two s there is an + + + align:start position:0% +that is a factor of two s there is an +improvement at lowgate bias but here at + + align:start position:0% +improvement at lowgate bias but here at + + + align:start position:0% +improvement at lowgate bias but here at +high effective field or High Gate bias + + align:start position:0% +high effective field or High Gate bias + + + align:start position:0% +high effective field or High Gate bias +the Improvement is is pretty small only + + align:start position:0% +the Improvement is is pretty small only + + + align:start position:0% +the Improvement is is pretty small only +a few percent um so but that just shows + + align:start position:0% +a few percent um so but that just shows + + + align:start position:0% +a few percent um so but that just shows +uh the state-ofthe-art as it exists uh a + + align:start position:0% +uh the state-ofthe-art as it exists uh a + + + align:start position:0% +uh the state-ofthe-art as it exists uh a +couple of years + + align:start position:0% +couple of years + + + align:start position:0% +couple of years +ago and if you working at relatively + + align:start position:0% +ago and if you working at relatively + + + align:start position:0% +ago and if you working at relatively +lowgate bias and you just want to get an + + align:start position:0% +lowgate bias and you just want to get an + + + align:start position:0% +lowgate bias and you just want to get an +idea of how the mobility enhancement + + align:start position:0% +idea of how the mobility enhancement + + + align:start position:0% +idea of how the mobility enhancement +varies with the amount of strain you can + + align:start position:0% +varies with the amount of strain you can + + + align:start position:0% +varies with the amount of strain you can +look at this curve on on page 22 this is + + align:start position:0% +look at this curve on on page 22 this is + + + align:start position:0% +look at this curve on on page 22 this is +the electron Mobility enhancement Factor + + align:start position:0% +the electron Mobility enhancement Factor + + + align:start position:0% +the electron Mobility enhancement Factor +so it's the peak mobility in a strained + + align:start position:0% +so it's the peak mobility in a strained + + + align:start position:0% +so it's the peak mobility in a strained +silicon fet divided the peak mobility in + + align:start position:0% +silicon fet divided the peak mobility in + + + align:start position:0% +silicon fet divided the peak mobility in +an unstrained fet and you see here with + + align:start position:0% +an unstrained fet and you see here with + + + align:start position:0% +an unstrained fet and you see here with +no strain that it's one and then it goes + + align:start position:0% +no strain that it's one and then it goes + + + align:start position:0% +no strain that it's one and then it goes +up to about a factor of 1.8 maybe two + + align:start position:0% +up to about a factor of 1.8 maybe two + + + align:start position:0% +up to about a factor of 1.8 maybe two +something like that there's a lot of + + align:start position:0% +something like that there's a lot of + + + align:start position:0% +something like that there's a lot of +data been published the last 10 or 12 + + align:start position:0% +data been published the last 10 or 12 + + + align:start position:0% +data been published the last 10 or 12 +years and they all seem to agree about + + align:start position:0% +years and they all seem to agree about + + + align:start position:0% +years and they all seem to agree about +this saturating + + align:start position:0% +this saturating + + + align:start position:0% +this saturating +behavior on the right is for pay loss + + align:start position:0% +behavior on the right is for pay loss + + + align:start position:0% +behavior on the right is for pay loss +for whole Mobility the data is does show + + align:start position:0% +for whole Mobility the data is does show + + + align:start position:0% +for whole Mobility the data is does show +an increase especially as you get above + + align:start position:0% +an increase especially as you get above + + + align:start position:0% +an increase especially as you get above +about 30% germanium you can get larger + + align:start position:0% +about 30% germanium you can get larger + + + align:start position:0% +about 30% germanium you can get larger +enhancement factors um and this is the + + align:start position:0% +enhancement factors um and this is the + + + align:start position:0% +enhancement factors um and this is the +theoretical curve the data seems to be a + + align:start position:0% +theoretical curve the data seems to be a + + + align:start position:0% +theoretical curve the data seems to be a +little bit below the theoretic curve but + + align:start position:0% +little bit below the theoretic curve but + + + align:start position:0% +little bit below the theoretic curve but +shows roughly the kind of strain + + align:start position:0% +shows roughly the kind of strain + + + align:start position:0% +shows roughly the kind of strain +dependence you would you expect and so + + align:start position:0% +dependence you would you expect and so + + + align:start position:0% +dependence you would you expect and so +what this is telling you you're + + align:start position:0% +what this is telling you you're + + + align:start position:0% +what this is telling you you're +saturating out you don't really need to + + align:start position:0% +saturating out you don't really need to + + + align:start position:0% +saturating out you don't really need to +put more for electrons more than about + + align:start position:0% +put more for electrons more than about + + + align:start position:0% +put more for electrons more than about +20% geranium in the substrate that's + + align:start position:0% +20% geranium in the substrate that's + + + align:start position:0% +20% geranium in the substrate that's +enough strain so the bands are split + + align:start position:0% +enough strain so the bands are split + + + align:start position:0% +enough strain so the bands are split +enough if you go beyond that you you're + + align:start position:0% +enough if you go beyond that you you're + + + align:start position:0% +enough if you go beyond that you you're +inducing more strain and more splitting + + align:start position:0% +inducing more strain and more splitting + + + align:start position:0% +inducing more strain and more splitting +but the mobility itself is not actually + + align:start position:0% +but the mobility itself is not actually + + + align:start position:0% +but the mobility itself is not actually +improving because something else is + + align:start position:0% +improving because something else is + + + align:start position:0% +improving because something else is +limiting the mobility that gives you a + + align:start position:0% +limiting the mobility that gives you a + + + align:start position:0% +limiting the mobility that gives you a +rough idea of the amount of strain you + + align:start position:0% +rough idea of the amount of strain you + + + align:start position:0% +rough idea of the amount of strain you +need to induce in some of these + + align:start position:0% +need to induce in some of these + + + align:start position:0% +need to induce in some of these +devices uh page 23 is is sort of a + + align:start position:0% +devices uh page 23 is is sort of a + + + align:start position:0% +devices uh page 23 is is sort of a +summary of uh some of the mobility + + align:start position:0% +summary of uh some of the mobility + + + align:start position:0% +summary of uh some of the mobility +enhancements now for + + align:start position:0% +enhancements now for + + + align:start position:0% +enhancements now for +pets uh it's the mobility enhancement + + align:start position:0% +pets uh it's the mobility enhancement + + + align:start position:0% +pets uh it's the mobility enhancement +ratio again this is a number you would + + align:start position:0% +ratio again this is a number you would + + + align:start position:0% +ratio again this is a number you would +like to be large as a function of + + align:start position:0% +like to be large as a function of + + + align:start position:0% +like to be large as a function of +vertical field if you operate the device + + align:start position:0% +vertical field if you operate the device + + + align:start position:0% +vertical field if you operate the device +at very low vertical Fields you can get + + align:start position:0% +at very low vertical Fields you can get + + + align:start position:0% +at very low vertical Fields you can get +large ratios but most mod devices + + align:start position:0% +large ratios but most mod devices + + + align:start position:0% +large ratios but most mod devices +operate over here so the enhancement + + align:start position:0% +operate over here so the enhancement + + + align:start position:0% +operate over here so the enhancement +factor is only about 1.1 or 1.2 it's + + align:start position:0% +factor is only about 1.1 or 1.2 it's + + + align:start position:0% +factor is only about 1.1 or 1.2 it's +approaching one uh that's a problem + + align:start position:0% +approaching one uh that's a problem + + + align:start position:0% +approaching one uh that's a problem +unless you go to very high geranium + + align:start position:0% +unless you go to very high geranium + + + align:start position:0% +unless you go to very high geranium +contents there's some data here with a + + align:start position:0% +contents there's some data here with a + + + align:start position:0% +contents there's some data here with a +40% substrate so that means the strain + + align:start position:0% +40% substrate so that means the strain + + + align:start position:0% +40% substrate so that means the strain +silicon layer is very thin and it's + + align:start position:0% +silicon layer is very thin and it's + + + align:start position:0% +silicon layer is very thin and it's +strained to a 40% substrate here + + align:start position:0% +strained to a 40% substrate here + + + align:start position:0% +strained to a 40% substrate here +Mobility enhan fact there's not a full + + align:start position:0% +Mobility enhan fact there's not a full + + + align:start position:0% +Mobility enhan fact there's not a full +curve available the highest uh um uh + + align:start position:0% +curve available the highest uh um uh + + + align:start position:0% +curve available the highest uh um uh +field these people went to was about 06 + + align:start position:0% +field these people went to was about 06 + + + align:start position:0% +field these people went to was about 06 +but they did get pretty large + + align:start position:0% +but they did get pretty large + + + align:start position:0% +but they did get pretty large +enhancement factors so um it looks like + + align:start position:0% +enhancement factors so um it looks like + + + align:start position:0% +enhancement factors so um it looks like +uh if you're going to use bi axial + + align:start position:0% +uh if you're going to use bi axial + + + align:start position:0% +uh if you're going to use bi axial +tensil strain in the Silicon you need to + + align:start position:0% +tensil strain in the Silicon you need to + + + align:start position:0% +tensil strain in the Silicon you need to +go to very high levels of strain uh uh + + align:start position:0% +go to very high levels of strain uh uh + + + align:start position:0% +go to very high levels of strain uh uh +if you want this to work so that's one + + align:start position:0% +if you want this to work so that's one + + + align:start position:0% +if you want this to work so that's one +big disadvantage uh for the pimos fit in + + align:start position:0% +big disadvantage uh for the pimos fit in + + + align:start position:0% +big disadvantage uh for the pimos fit in +this + + align:start position:0% + + + + align:start position:0% + +technology oh just another um uh um + + align:start position:0% +technology oh just another um uh um + + + align:start position:0% +technology oh just another um uh um +graph on on page 24 to give you an idea + + align:start position:0% +graph on on page 24 to give you an idea + + + align:start position:0% +graph on on page 24 to give you an idea +we talked about about Mobility how about + + align:start position:0% +we talked about about Mobility how about + + + align:start position:0% +we talked about about Mobility how about +things that you uh care about like + + align:start position:0% +things that you uh care about like + + + align:start position:0% +things that you uh care about like +electron velocity or or GM that a lot of + + align:start position:0% +electron velocity or or GM that a lot of + + + align:start position:0% +electron velocity or or GM that a lot of +circuit designers are worried about well + + align:start position:0% +circuit designers are worried about well + + + align:start position:0% +circuit designers are worried about well +indeed that does improve and even as you + + align:start position:0% +indeed that does improve and even as you + + + align:start position:0% +indeed that does improve and even as you +scale devices this is data back from + + align:start position:0% +scale devices this is data back from + + + align:start position:0% +scale devices this is data back from +1998 now it's fairly old but it it still + + align:start position:0% +1998 now it's fairly old but it it still + + + align:start position:0% +1998 now it's fairly old but it it still +uh gives you an idea of if you look at + + align:start position:0% +uh gives you an idea of if you look at + + + align:start position:0% +uh gives you an idea of if you look at +the GM here for an unstrained device + + align:start position:0% +the GM here for an unstrained device + + + align:start position:0% +the GM here for an unstrained device +shown in red as you scale it goes up + + align:start position:0% +shown in red as you scale it goes up + + + align:start position:0% +shown in red as you scale it goes up +like this for a strained n mosfet shown + + align:start position:0% +like this for a strained n mosfet shown + + + align:start position:0% +like this for a strained n mosfet shown +in blue it goes up and this enhancement + + align:start position:0% +in blue it goes up and this enhancement + + + align:start position:0% +in blue it goes up and this enhancement +factor or the the the ratio between + + align:start position:0% +factor or the the the ratio between + + + align:start position:0% +factor or the the the ratio between +these two lines stays about constant in + + align:start position:0% +these two lines stays about constant in + + + align:start position:0% +these two lines stays about constant in +this plot all the way down to about U 90 + + align:start position:0% +this plot all the way down to about U 90 + + + align:start position:0% +this plot all the way down to about U 90 +nanometers or or so was the shortest + + align:start position:0% +nanometers or or so was the shortest + + + align:start position:0% +nanometers or or so was the shortest +devices that were made just just around + + align:start position:0% +devices that were made just just around + + + align:start position:0% +devices that were made just just around +100 nanometers since that time shorter + + align:start position:0% +100 nanometers since that time shorter + + + align:start position:0% +100 nanometers since that time shorter +devices have been made but there so the + + align:start position:0% +devices have been made but there so the + + + align:start position:0% +devices have been made but there so the +the nice thing is that the enhancement + + align:start position:0% +the nice thing is that the enhancement + + + align:start position:0% +the nice thing is that the enhancement +doesn't seem to go away when you go to + + align:start position:0% +doesn't seem to go away when you go to + + + align:start position:0% +doesn't seem to go away when you go to +short channels so that's very important + + align:start position:0% +short channels so that's very important + + + align:start position:0% +short channels so that's very important +for the + + align:start position:0% + + + + align:start position:0% + +technology so let me talk a little bit + + align:start position:0% +technology so let me talk a little bit + + + align:start position:0% +technology so let me talk a little bit +but now I want to spend a few minutes on + + align:start position:0% +but now I want to spend a few minutes on + + + align:start position:0% +but now I want to spend a few minutes on +how the material is grown and some of + + align:start position:0% +how the material is grown and some of + + + align:start position:0% +how the material is grown and some of +the issues related to how uh how dopant + + align:start position:0% +the issues related to how uh how dopant + + + align:start position:0% +the issues related to how uh how dopant +diffus in this + + align:start position:0% + + + + align:start position:0% + +material slide 26 just shows some + + align:start position:0% +material slide 26 just shows some + + + align:start position:0% +material slide 26 just shows some +typical gas sources that are used uh a + + align:start position:0% +typical gas sources that are used uh a + + + align:start position:0% +typical gas sources that are used uh a +very common way to grow this is by low + + align:start position:0% +very common way to grow this is by low + + + align:start position:0% +very common way to grow this is by low +pressure CBD or sometimes ultra high + + align:start position:0% +pressure CBD or sometimes ultra high + + + align:start position:0% +pressure CBD or sometimes ultra high +vacuum CBD uh depending on the uh uh the + + align:start position:0% +vacuum CBD uh depending on the uh uh the + + + align:start position:0% +vacuum CBD uh depending on the uh uh the +particular uh lab that's doing the work + + align:start position:0% +particular uh lab that's doing the work + + + align:start position:0% +particular uh lab that's doing the work +uh for epitaxial silicon geranium a very + + align:start position:0% +uh for epitaxial silicon geranium a very + + + align:start position:0% +uh for epitaxial silicon geranium a very +common silicon source is siline uh + + align:start position:0% +common silicon source is siline uh + + + align:start position:0% +common silicon source is siline uh +sometimes people use dorosy we've talked + + align:start position:0% +sometimes people use dorosy we've talked + + + align:start position:0% +sometimes people use dorosy we've talked +about dor earlier in the class for + + align:start position:0% +about dor earlier in the class for + + + align:start position:0% +about dor earlier in the class for +germanian people use germine what is + + align:start position:0% +germanian people use germine what is + + + align:start position:0% +germanian people use germine what is +gerine it's the same as siling but you + + align:start position:0% +gerine it's the same as siling but you + + + align:start position:0% +gerine it's the same as siling but you +take out the silicon and you put in a + + align:start position:0% +take out the silicon and you put in a + + + align:start position:0% +take out the silicon and you put in a +germanium atom so it's + + align:start position:0% +germanium atom so it's + + + align:start position:0% +germanium atom so it's +G4 um hydrogen is often used as a cargas + + align:start position:0% +G4 um hydrogen is often used as a cargas + + + align:start position:0% +G4 um hydrogen is often used as a cargas +although not in uhv CBD but in low + + align:start position:0% +although not in uhv CBD but in low + + + align:start position:0% +although not in uhv CBD but in low +pressure CBD and these are common + + align:start position:0% +pressure CBD and these are common + + + align:start position:0% +pressure CBD and these are common +dopants dorine and arcene are used for p + + align:start position:0% +dopants dorine and arcene are used for p + + + align:start position:0% +dopants dorine and arcene are used for p +and end type doping uh sometimes + + align:start position:0% +and end type doping uh sometimes + + + align:start position:0% +and end type doping uh sometimes +phosphine um for silicon geranium in a + + align:start position:0% +phosphine um for silicon geranium in a + + + align:start position:0% +phosphine um for silicon geranium in a +selective process you need to add so if + + align:start position:0% +selective process you need to add so if + + + align:start position:0% +selective process you need to add so if +you want to deposit silicon geranium on + + align:start position:0% +you want to deposit silicon geranium on + + + align:start position:0% +you want to deposit silicon geranium on +a wa for that has oxide on it and little + + align:start position:0% +a wa for that has oxide on it and little + + + align:start position:0% +a wa for that has oxide on it and little +openings in the oxide uh where there's + + align:start position:0% +openings in the oxide uh where there's + + + align:start position:0% +openings in the oxide uh where there's +uh windows that that are that are + + align:start position:0% +uh windows that that are that are + + + align:start position:0% +uh windows that that are that are +patterned so that you can reach down + + align:start position:0% +patterned so that you can reach down + + + align:start position:0% +patterned so that you can reach down +into the Silicon this is called + + align:start position:0% +into the Silicon this is called + + + align:start position:0% +into the Silicon this is called +selective deposition you need to add + + align:start position:0% +selective deposition you need to add + + + align:start position:0% +selective deposition you need to add +hydrogen chloride HCL and this is + + align:start position:0% +hydrogen chloride HCL and this is + + + align:start position:0% +hydrogen chloride HCL and this is +commonly done for both the bipolar and + + align:start position:0% +commonly done for both the bipolar and + + + align:start position:0% +commonly done for both the bipolar and +seamoss + + align:start position:0% +seamoss + + + align:start position:0% +seamoss +applications for silicon geranium carbon + + align:start position:0% +applications for silicon geranium carbon + + + align:start position:0% +applications for silicon geranium carbon +uh you do the same type of thing but you + + align:start position:0% +uh you do the same type of thing but you + + + align:start position:0% +uh you do the same type of thing but you +add one more gas which is called methyl + + align:start position:0% +add one more gas which is called methyl + + + align:start position:0% +add one more gas which is called methyl +siline at that the methyl group The ch3 + + align:start position:0% +siline at that the methyl group The ch3 + + + align:start position:0% +siline at that the methyl group The ch3 +brings in the carbon which is used uh to + + align:start position:0% +brings in the carbon which is used uh to + + + align:start position:0% +brings in the carbon which is used uh to +dope those + + align:start position:0% + + + + align:start position:0% + +devices uh we talked a little bit about + + align:start position:0% +devices uh we talked a little bit about + + + align:start position:0% +devices uh we talked a little bit about +strain and here on slide uh 27 I'm + + align:start position:0% +strain and here on slide uh 27 I'm + + + align:start position:0% +strain and here on slide uh 27 I'm +showing a little bit of idea what that + + align:start position:0% +showing a little bit of idea what that + + + align:start position:0% +showing a little bit of idea what that +means uh this ball and stick diagram on + + align:start position:0% +means uh this ball and stick diagram on + + + align:start position:0% +means uh this ball and stick diagram on +the lower right was our our pictorial + + align:start position:0% +the lower right was our our pictorial + + + align:start position:0% +the lower right was our our pictorial +picture in our heads when the epil layer + + align:start position:0% +picture in our heads when the epil layer + + + align:start position:0% +picture in our heads when the epil layer +is thin we said the Silicon geranium if + + align:start position:0% +is thin we said the Silicon geranium if + + + align:start position:0% +is thin we said the Silicon geranium if +it's thin enough it will compress in X + + align:start position:0% +it's thin enough it will compress in X + + + align:start position:0% +it's thin enough it will compress in X +and Y it will match the parameter of the + + align:start position:0% +and Y it will match the parameter of the + + + align:start position:0% +and Y it will match the parameter of the +of the thick substrate uh that's only + + align:start position:0% +of the thick substrate uh that's only + + + align:start position:0% +of the thick substrate uh that's only +when it's thin enough and it's + + align:start position:0% +when it's thin enough and it's + + + align:start position:0% +when it's thin enough and it's +energetically favorable to to um bend + + align:start position:0% +energetically favorable to to um bend + + + align:start position:0% +energetically favorable to to um bend +the bonds uh in that case we say it's + + align:start position:0% +the bonds uh in that case we say it's + + + align:start position:0% +the bonds uh in that case we say it's +fully strained if you build up more and + + align:start position:0% +fully strained if you build up more and + + + align:start position:0% +fully strained if you build up more and +more layers you build up more and more + + align:start position:0% +more layers you build up more and more + + + align:start position:0% +more layers you build up more and more +stress at some point it becomes + + align:start position:0% +stress at some point it becomes + + + align:start position:0% +stress at some point it becomes +energetically pable to break bonds so at + + align:start position:0% +energetically pable to break bonds so at + + + align:start position:0% +energetically pable to break bonds so at +this interface bonds are actually broken + + align:start position:0% +this interface bonds are actually broken + + + align:start position:0% +this interface bonds are actually broken +and is represented here by these U + + align:start position:0% +and is represented here by these U + + + align:start position:0% +and is represented here by these U +Misfit dislocations that are going into + + align:start position:0% +Misfit dislocations that are going into + + + align:start position:0% +Misfit dislocations that are going into +the board or into the uh into the um + + align:start position:0% +the board or into the uh into the um + + + align:start position:0% +the board or into the uh into the um +into the board here and so these the + + align:start position:0% +into the board here and so these the + + + align:start position:0% +into the board here and so these the +dislocations uh end up relieving The + + align:start position:0% +dislocations uh end up relieving The + + + align:start position:0% +dislocations uh end up relieving The +Strain in a thick layer uh they have a + + align:start position:0% +Strain in a thick layer uh they have a + + + align:start position:0% +Strain in a thick layer uh they have a +certain spacing and if you have enough + + align:start position:0% +certain spacing and if you have enough + + + align:start position:0% +certain spacing and if you have enough +of them and their spacing is tight + + align:start position:0% +of them and their spacing is tight + + + align:start position:0% +of them and their spacing is tight +enough in fact you'll end up with a + + align:start position:0% +enough in fact you'll end up with a + + + align:start position:0% +enough in fact you'll end up with a +fully relaxed layer the Silicon geranium + + align:start position:0% +fully relaxed layer the Silicon geranium + + + align:start position:0% +fully relaxed layer the Silicon geranium +will have a last parameter that it has + + align:start position:0% +will have a last parameter that it has + + + align:start position:0% +will have a last parameter that it has +an + + align:start position:0% +an + + + align:start position:0% +an +equilibrium and this is a cross-section + + align:start position:0% +equilibrium and this is a cross-section + + + align:start position:0% +equilibrium and this is a cross-section +view in the upper right on and this uh + + align:start position:0% +view in the upper right on and this uh + + + align:start position:0% +view in the upper right on and this uh +transmission electron micrograph is a + + align:start position:0% +transmission electron micrograph is a + + + align:start position:0% +transmission electron micrograph is a +planer view so if you look down through + + align:start position:0% +planer view so if you look down through + + + align:start position:0% +planer view so if you look down through +an epitaxial layer that's been grown to + + align:start position:0% +an epitaxial layer that's been grown to + + + align:start position:0% +an epitaxial layer that's been grown to +be too thick and here is a is a bird's + + align:start position:0% +be too thick and here is a is a bird's + + + align:start position:0% +be too thick and here is a is a bird's +eye view this is a misfit dislocation + + align:start position:0% +eye view this is a misfit dislocation + + + align:start position:0% +eye view this is a misfit dislocation +segment along the interface and there's + + align:start position:0% +segment along the interface and there's + + + align:start position:0% +segment along the interface and there's +a dislocation arm that threads to the + + align:start position:0% +a dislocation arm that threads to the + + + align:start position:0% +a dislocation arm that threads to the +surface and these dark lines end up + + align:start position:0% +surface and these dark lines end up + + + align:start position:0% +surface and these dark lines end up +having uh extra electron defraction + + align:start position:0% +having uh extra electron defraction + + + align:start position:0% +having uh extra electron defraction +contrast in the TM these dark lines + + align:start position:0% +contrast in the TM these dark lines + + + align:start position:0% +contrast in the TM these dark lines +correspond to Misfit dislocations at + + align:start position:0% +correspond to Misfit dislocations at + + + align:start position:0% +correspond to Misfit dislocations at +this interface and they run along the + + align:start position:0% +this interface and they run along the + + + align:start position:0% +this interface and they run along the +easy slip planes in Silicon uh and + + align:start position:0% +easy slip planes in Silicon uh and + + + align:start position:0% +easy slip planes in Silicon uh and +silicon Germania which they run along + + align:start position:0% +silicon Germania which they run along + + + align:start position:0% +silicon Germania which they run along +the 110 Direction so just typically + + align:start position:0% +the 110 Direction so just typically + + + align:start position:0% +the 110 Direction so just typically +parallel and perpendicular to the flat + + align:start position:0% +parallel and perpendicular to the flat + + + align:start position:0% +parallel and perpendicular to the flat +so this filam was grown to be a little + + align:start position:0% +so this filam was grown to be a little + + + align:start position:0% +so this filam was grown to be a little +bit too thick and it started to form + + align:start position:0% +bit too thick and it started to form + + + align:start position:0% +bit too thick and it started to form +dislocations it's snow fully + + align:start position:0% +dislocations it's snow fully + + + align:start position:0% +dislocations it's snow fully +strained uh in fact you may be wondering + + align:start position:0% +strained uh in fact you may be wondering + + + align:start position:0% +strained uh in fact you may be wondering +oh well how thick is too thick uh well + + align:start position:0% +oh well how thick is too thick uh well + + + align:start position:0% +oh well how thick is too thick uh well +there is no one number unfortunately + + align:start position:0% +there is no one number unfortunately + + + align:start position:0% +there is no one number unfortunately +there um for a long time people thought + + align:start position:0% +there um for a long time people thought + + + align:start position:0% +there um for a long time people thought +there was a quote unquote critical + + align:start position:0% +there was a quote unquote critical + + + align:start position:0% +there was a quote unquote critical +thickness so that at a particular + + align:start position:0% +thickness so that at a particular + + + align:start position:0% +thickness so that at a particular +Germania fraction when you go above that + + align:start position:0% +Germania fraction when you go above that + + + align:start position:0% +Germania fraction when you go above that +thickness Bingo you get dislocations + + align:start position:0% +thickness Bingo you get dislocations + + + align:start position:0% +thickness Bingo you get dislocations +doesn't quite happen that way uh in fact + + align:start position:0% +doesn't quite happen that way uh in fact + + + align:start position:0% +doesn't quite happen that way uh in fact +there is a whole metastable + + align:start position:0% +there is a whole metastable + + + align:start position:0% +there is a whole metastable +regime and the critical thickness + + align:start position:0% +regime and the critical thickness + + + align:start position:0% +regime and the critical thickness +depends on the temperature at which + + align:start position:0% +depends on the temperature at which + + + align:start position:0% +depends on the temperature at which +you're doing the growth because it's a + + align:start position:0% +you're doing the growth because it's a + + + align:start position:0% +you're doing the growth because it's a +kinetically li limited process and this + + align:start position:0% +kinetically li limited process and this + + + align:start position:0% +kinetically li limited process and this +is a good paper Derek Hon's paper from + + align:start position:0% +is a good paper Derek Hon's paper from + + + align:start position:0% +is a good paper Derek Hon's paper from +1991 who describes the kinetic model and + + align:start position:0% +1991 who describes the kinetic model and + + + align:start position:0% +1991 who describes the kinetic model and +explains the fact that there's no one + + align:start position:0% +explains the fact that there's no one + + + align:start position:0% +explains the fact that there's no one +critical thickness at a given geranium + + align:start position:0% +critical thickness at a given geranium + + + align:start position:0% +critical thickness at a given geranium +fraction uh what he plotted here was a + + align:start position:0% +fraction uh what he plotted here was a + + + align:start position:0% +fraction uh what he plotted here was a +summary of the critical thickness uh + + align:start position:0% +summary of the critical thickness uh + + + align:start position:0% +summary of the critical thickness uh +above which dislocations form as a + + align:start position:0% +above which dislocations form as a + + + align:start position:0% +above which dislocations form as a +function of geranium fraction of the + + align:start position:0% +function of geranium fraction of the + + + align:start position:0% +function of geranium fraction of the +Silicon geranium layer for different + + align:start position:0% +Silicon geranium layer for different + + + align:start position:0% +Silicon geranium layer for different +growth temperatures so if you're growing + + align:start position:0% +growth temperatures so if you're growing + + + align:start position:0% +growth temperatures so if you're growing +at 900° you're very hot and it's very + + align:start position:0% +at 900° you're very hot and it's very + + + align:start position:0% +at 900° you're very hot and it's very +easy to nucleate dislocations and they + + align:start position:0% +easy to nucleate dislocations and they + + + align:start position:0% +easy to nucleate dislocations and they +travel very rapidly + + align:start position:0% +travel very rapidly + + + align:start position:0% +travel very rapidly +you tend to then get the equilibrium + + align:start position:0% +you tend to then get the equilibrium + + + align:start position:0% +you tend to then get the equilibrium +critical thickness that this this line + + align:start position:0% +critical thickness that this this line + + + align:start position:0% +critical thickness that this this line +here so if you're growing at high + + align:start position:0% +here so if you're growing at high + + + align:start position:0% +here so if you're growing at high +temperature or you kneeling at high + + align:start position:0% +temperature or you kneeling at high + + + align:start position:0% +temperature or you kneeling at high +temperature if you're at 20% the + + align:start position:0% +temperature if you're at 20% the + + + align:start position:0% +temperature if you're at 20% the +equilibrium critical thickness for + + align:start position:0% +equilibrium critical thickness for + + + align:start position:0% +equilibrium critical thickness for +silicon Germania is about 120 angstroms + + align:start position:0% +silicon Germania is about 120 angstroms + + + align:start position:0% +silicon Germania is about 120 angstroms +110 angstrum something like that so that + + align:start position:0% +110 angstrum something like that so that + + + align:start position:0% +110 angstrum something like that so that +says that if you're growing at high + + align:start position:0% +says that if you're growing at high + + + align:start position:0% +says that if you're growing at high +temperature and you grow above about 120 + + align:start position:0% +temperature and you grow above about 120 + + + align:start position:0% +temperature and you grow above about 120 +Anum of 20% silicon geranium it will + + align:start position:0% +Anum of 20% silicon geranium it will + + + align:start position:0% +Anum of 20% silicon geranium it will +start to form + + align:start position:0% +start to form + + + align:start position:0% +start to form +dislocations uh at that point however if + + align:start position:0% +dislocations uh at that point however if + + + align:start position:0% +dislocations uh at that point however if +you are growing that same germanium + + align:start position:0% +you are growing that same germanium + + + align:start position:0% +you are growing that same germanium +fraction at 550 say so you're in a very + + align:start position:0% +fraction at 550 say so you're in a very + + + align:start position:0% +fraction at 550 say so you're in a very +low temperature epitaxial growth you are + + align:start position:0% +low temperature epitaxial growth you are + + + align:start position:0% +low temperature epitaxial growth you are +kinetically suppressing the formation of + + align:start position:0% +kinetically suppressing the formation of + + + align:start position:0% +kinetically suppressing the formation of +dislocations in fact the critical + + align:start position:0% +dislocations in fact the critical + + + align:start position:0% +dislocations in fact the critical +thickness is like this curve here it's + + align:start position:0% +thickness is like this curve here it's + + + align:start position:0% +thickness is like this curve here it's +about 700 + + align:start position:0% +about 700 + + + align:start position:0% +about 700 +an so you can there's a metastable + + align:start position:0% +an so you can there's a metastable + + + align:start position:0% +an so you can there's a metastable +regime if you grow the layers thin + + align:start position:0% +regime if you grow the layers thin + + + align:start position:0% +regime if you grow the layers thin +enough you can keep them strained and + + align:start position:0% +enough you can keep them strained and + + + align:start position:0% +enough you can keep them strained and +they won't form dislocations until a + + align:start position:0% +they won't form dislocations until a + + + align:start position:0% +they won't form dislocations until a +much thicker layer the problem with that + + align:start position:0% +much thicker layer the problem with that + + + align:start position:0% +much thicker layer the problem with that +is you can grow them very thin at high + + align:start position:0% +is you can grow them very thin at high + + + align:start position:0% +is you can grow them very thin at high +temperature very thick and they won't + + align:start position:0% +temperature very thick and they won't + + + align:start position:0% +temperature very thick and they won't +have dislocations but if you go to + + align:start position:0% +have dislocations but if you go to + + + align:start position:0% +have dislocations but if you go to +process them to make a device at a + + align:start position:0% +process them to make a device at a + + + align:start position:0% +process them to make a device at a +higher temperature dislocations can can + + align:start position:0% +higher temperature dislocations can can + + + align:start position:0% +higher temperature dislocations can can +pop in if you're above the equilibrium + + align:start position:0% +pop in if you're above the equilibrium + + + align:start position:0% +pop in if you're above the equilibrium +critical thickness so this region is + + align:start position:0% +critical thickness so this region is + + + align:start position:0% +critical thickness so this region is +called metastable because you can grow + + align:start position:0% +called metastable because you can grow + + + align:start position:0% +called metastable because you can grow +them at low temperatures without + + align:start position:0% +them at low temperatures without + + + align:start position:0% +them at low temperatures without +dislocations but if you were to kneel + + align:start position:0% +dislocations but if you were to kneel + + + align:start position:0% +dislocations but if you were to kneel +them at a higher temperature dislocation + + align:start position:0% +them at a higher temperature dislocation + + + align:start position:0% +them at a higher temperature dislocation +would form and it would start to + + align:start position:0% +would form and it would start to + + + align:start position:0% +would form and it would start to +relax generally this region up here up + + align:start position:0% +relax generally this region up here up + + + align:start position:0% +relax generally this region up here up +in the upper right so it's very thick + + align:start position:0% +in the upper right so it's very thick + + + align:start position:0% +in the upper right so it's very thick +films are almost always relaxed they'll + + align:start position:0% +films are almost always relaxed they'll + + + align:start position:0% +films are almost always relaxed they'll +always have dislocations so but I refer + + align:start position:0% +always have dislocations so but I refer + + + align:start position:0% +always have dislocations so but I refer +you to this 1991 paper for a good + + align:start position:0% +you to this 1991 paper for a good + + + align:start position:0% +you to this 1991 paper for a good +reference on understanding uh uh the + + align:start position:0% +reference on understanding uh uh the + + + align:start position:0% +reference on understanding uh uh the +formation of Misfits um in in strain + + align:start position:0% +formation of Misfits um in in strain + + + align:start position:0% +formation of Misfits um in in strain +silicon tranium layers + + align:start position:0% +silicon tranium layers + + + align:start position:0% +silicon tranium layers +Clyde uh + + align:start position:0% +Clyde uh + + + align:start position:0% +Clyde uh +29 uh it turns out in the early + + align:start position:0% +29 uh it turns out in the early + + + align:start position:0% +29 uh it turns out in the early +1990s uh there was some breakthroughs on + + align:start position:0% +1990s uh there was some breakthroughs on + + + align:start position:0% +1990s uh there was some breakthroughs on +you said well growing strain silicon + + align:start position:0% +you said well growing strain silicon + + + align:start position:0% +you said well growing strain silicon +geranium that's very interesting people + + align:start position:0% +geranium that's very interesting people + + + align:start position:0% +geranium that's very interesting people +want to do that there were actually some + + align:start position:0% +want to do that there were actually some + + + align:start position:0% +want to do that there were actually some +breakthroughs on how to grow relaxed + + align:start position:0% +breakthroughs on how to grow relaxed + + + align:start position:0% +breakthroughs on how to grow relaxed +silicon geran this seems like it should + + align:start position:0% +silicon geran this seems like it should + + + align:start position:0% +silicon geran this seems like it should +be very easy to make the Silicon geran + + align:start position:0% +be very easy to make the Silicon geran + + + align:start position:0% +be very easy to make the Silicon geran +relax you just grow it thick right we + + align:start position:0% +relax you just grow it thick right we + + + align:start position:0% +relax you just grow it thick right we +just saw that paper from Derek hton well + + align:start position:0% +just saw that paper from Derek hton well + + + align:start position:0% +just saw that paper from Derek hton well +if I'm at 30% I just grow it to be uh + + align:start position:0% +if I'm at 30% I just grow it to be uh + + + align:start position:0% +if I'm at 30% I just grow it to be uh +you know three or four microns up here + + align:start position:0% +you know three or four microns up here + + + align:start position:0% +you know three or four microns up here +it'll definitely be above the critical + + align:start position:0% +it'll definitely be above the critical + + + align:start position:0% +it'll definitely be above the critical +thickness it will be relaxed it'll have + + align:start position:0% +thickness it will be relaxed it'll have + + + align:start position:0% +thickness it will be relaxed it'll have +its own lattice parameter the problem + + align:start position:0% +its own lattice parameter the problem + + + align:start position:0% +its own lattice parameter the problem +with that if you just grow it uh right + + align:start position:0% +with that if you just grow it uh right + + + align:start position:0% +with that if you just grow it uh right +off the bat like that a box layer you + + align:start position:0% +off the bat like that a box layer you + + + align:start position:0% +off the bat like that a box layer you +end up with um a huge number of + + align:start position:0% +end up with um a huge number of + + + align:start position:0% +end up with um a huge number of +threading + + align:start position:0% +threading + + + align:start position:0% +threading +dislocations um so if you don't grade + + align:start position:0% +dislocations um so if you don't grade + + + align:start position:0% +dislocations um so if you don't grade +the profile you end up with more than 10 + + align:start position:0% +the profile you end up with more than 10 + + + align:start position:0% +the profile you end up with more than 10 +of the nth maybe 10 of the 10th of these + + align:start position:0% +of the nth maybe 10 of the 10th of these + + + align:start position:0% +of the nth maybe 10 of the 10th of these +threading arms these for every Miss bit + + align:start position:0% +threading arms these for every Miss bit + + + align:start position:0% +threading arms these for every Miss bit +you have an arm that two arms that go up + + align:start position:0% +you have an arm that two arms that go up + + + align:start position:0% +you have an arm that two arms that go up +to the to the surface and you have so + + align:start position:0% +to the to the surface and you have so + + + align:start position:0% +to the to the surface and you have so +many of them that the the layers aren't + + align:start position:0% +many of them that the the layers aren't + + + align:start position:0% +many of them that the the layers aren't +very useful for very many many devices + + align:start position:0% +very useful for very many many devices + + + align:start position:0% +very useful for very many many devices +because there's too many + + align:start position:0% +because there's too many + + + align:start position:0% +because there's too many +defects but in the early 90s there were + + align:start position:0% +defects but in the early 90s there were + + + align:start position:0% +defects but in the early 90s there were +breakthroughs on how to grow these + + align:start position:0% +breakthroughs on how to grow these + + + align:start position:0% +breakthroughs on how to grow these +layers uh how to grow them at high + + align:start position:0% +layers uh how to grow them at high + + + align:start position:0% +layers uh how to grow them at high +enough temperature so the threading arms + + align:start position:0% +enough temperature so the threading arms + + + align:start position:0% +enough temperature so the threading arms +could run to the edge of the wafer and + + align:start position:0% +could run to the edge of the wafer and + + + align:start position:0% +could run to the edge of the wafer and +how to grade the geranium content so you + + align:start position:0% +how to grade the geranium content so you + + + align:start position:0% +how to grade the geranium content so you +start growing it's it's silicon lattice + + align:start position:0% +start growing it's it's silicon lattice + + + align:start position:0% +start growing it's it's silicon lattice +and then you gradually add geranium as + + align:start position:0% +and then you gradually add geranium as + + + align:start position:0% +and then you gradually add geranium as +you go up and you grade it over many + + align:start position:0% +you go up and you grade it over many + + + align:start position:0% +you go up and you grade it over many +microns it turns out when you do that + + align:start position:0% +microns it turns out when you do that + + + align:start position:0% +microns it turns out when you do that +you can relax the Silicon geranium but + + align:start position:0% +you can relax the Silicon geranium but + + + align:start position:0% +you can relax the Silicon geranium but +you can reduce the number of arms that + + align:start position:0% +you can reduce the number of arms that + + + align:start position:0% +you can reduce the number of arms that +thread to the surface all the arms run + + align:start position:0% +thread to the surface all the arms run + + + align:start position:0% +thread to the surface all the arms run +out to the edge of the wafer where you + + align:start position:0% +out to the edge of the wafer where you + + + align:start position:0% +out to the edge of the wafer where you +don't care about them because you're not + + align:start position:0% +don't care about them because you're not + + + align:start position:0% +don't care about them because you're not +going to make any devices at the edge of + + align:start position:0% +going to make any devices at the edge of + + + align:start position:0% +going to make any devices at the edge of +the wafer so the threading dislocation + + align:start position:0% +the wafer so the threading dislocation + + + align:start position:0% +the wafer so the threading dislocation +density can go down from 10 to the 9th + + align:start position:0% +density can go down from 10 to the 9th + + + align:start position:0% +density can go down from 10 to the 9th +to less than 10 the 5ifth if you do the + + align:start position:0% +to less than 10 the 5ifth if you do the + + + align:start position:0% +to less than 10 the 5ifth if you do the +grading right um so the nice thing about + + align:start position:0% +grading right um so the nice thing about + + + align:start position:0% +grading right um so the nice thing about +this is all of a sudden on Silicon + + align:start position:0% +this is all of a sudden on Silicon + + + align:start position:0% +this is all of a sudden on Silicon +substrates in the early 90s people had a + + align:start position:0% +substrates in the early 90s people had a + + + align:start position:0% +substrates in the early 90s people had a +way to take a silicon substrate grow a + + align:start position:0% +way to take a silicon substrate grow a + + + align:start position:0% +way to take a silicon substrate grow a +relaxed silicon germanium layer and had + + align:start position:0% +relaxed silicon germanium layer and had + + + align:start position:0% +relaxed silicon germanium layer and had +it be pretty high quality a reasonable + + align:start position:0% +it be pretty high quality a reasonable + + + align:start position:0% +it be pretty high quality a reasonable +enough high quality that you can make + + align:start position:0% +enough high quality that you can make + + + align:start position:0% +enough high quality that you can make +devices um on it there work there's + + align:start position:0% +devices um on it there work there's + + + align:start position:0% +devices um on it there work there's +still a lot of threading dislocations + + align:start position:0% +still a lot of threading dislocations + + + align:start position:0% +still a lot of threading dislocations +but not enough to screw up other devices + + align:start position:0% +but not enough to screw up other devices + + + align:start position:0% +but not enough to screw up other devices +too badly so that was kind of the + + align:start position:0% +too badly so that was kind of the + + + align:start position:0% +too badly so that was kind of the +Breakthrough that enabled people to make + + align:start position:0% +Breakthrough that enabled people to make + + + align:start position:0% +Breakthrough that enabled people to make +relaxed silicon geranium and then strain + + align:start position:0% +relaxed silicon geranium and then strain + + + align:start position:0% +relaxed silicon geranium and then strain +silicon mosfets on top of + + align:start position:0% +silicon mosfets on top of + + + align:start position:0% +silicon mosfets on top of +it um what are some of the materials + + align:start position:0% +it um what are some of the materials + + + align:start position:0% +it um what are some of the materials +issues if you're growing this uh relaxed + + align:start position:0% +issues if you're growing this uh relaxed + + + align:start position:0% +issues if you're growing this uh relaxed +silicon geranium well I already + + align:start position:0% +silicon geranium well I already + + + align:start position:0% +silicon geranium well I already +mentioned the threading dislocation + + align:start position:0% +mentioned the threading dislocation + + + align:start position:0% +mentioned the threading dislocation +density uh it actually decreases if you + + align:start position:0% +density uh it actually decreases if you + + + align:start position:0% +density uh it actually decreases if you +go to higher growth temperatures because + + align:start position:0% +go to higher growth temperatures because + + + align:start position:0% +go to higher growth temperatures because +the dislocations can move faster uh the + + align:start position:0% +the dislocations can move faster uh the + + + align:start position:0% +the dislocations can move faster uh the +problem though is uh you also tend to + + align:start position:0% +problem though is uh you also tend to + + + align:start position:0% +problem though is uh you also tend to +get um a buried strain field that + + align:start position:0% +get um a buried strain field that + + + align:start position:0% +get um a buried strain field that +creates a cross-hatch in fact if you + + align:start position:0% +creates a cross-hatch in fact if you + + + align:start position:0% +creates a cross-hatch in fact if you +look at this um a plan View Optical + + align:start position:0% +look at this um a plan View Optical + + + align:start position:0% +look at this um a plan View Optical +micrograph of a relaxed silk and + + align:start position:0% +micrograph of a relaxed silk and + + + align:start position:0% +micrograph of a relaxed silk and +geranium layer it looks like a plaid + + align:start position:0% +geranium layer it looks like a plaid + + + align:start position:0% +geranium layer it looks like a plaid +shirt this plaid is that buried strain + + align:start position:0% +shirt this plaid is that buried strain + + + align:start position:0% +shirt this plaid is that buried strain +field causes the surface to undulate + + align:start position:0% +field causes the surface to undulate + + + align:start position:0% +field causes the surface to undulate +ever so slightly maybe 100 anstrom high + + align:start position:0% +ever so slightly maybe 100 anstrom high + + + align:start position:0% +ever so slightly maybe 100 anstrom high +Hills and Valleys very smooth and the + + align:start position:0% +Hills and Valleys very smooth and the + + + align:start position:0% +Hills and Valleys very smooth and the +period of these undulations or the + + align:start position:0% +period of these undulations or the + + + align:start position:0% +period of these undulations or the +spacing is quite large it can be microns + + align:start position:0% +spacing is quite large it can be microns + + + align:start position:0% +spacing is quite large it can be microns +uh so these are these are smooth + + align:start position:0% +uh so these are these are smooth + + + align:start position:0% +uh so these are these are smooth +undulations They Don't Really mess they + + align:start position:0% +undulations They Don't Really mess they + + + align:start position:0% +undulations They Don't Really mess they +don't mess with the electron Mobility + + align:start position:0% +don't mess with the electron Mobility + + + align:start position:0% +don't mess with the electron Mobility +electrons and holes don't care about + + align:start position:0% +electrons and holes don't care about + + + align:start position:0% +electrons and holes don't care about +them they don't it makes the Wafers look + + align:start position:0% +them they don't it makes the Wafers look + + + align:start position:0% +them they don't it makes the Wafers look +ugly + + align:start position:0% +ugly + + + align:start position:0% +ugly +however and it makes lithography a + + align:start position:0% +however and it makes lithography a + + + align:start position:0% +however and it makes lithography a +little difficult because Optical + + align:start position:0% +little difficult because Optical + + + align:start position:0% +little difficult because Optical +machines don't like looking at plaid + + align:start position:0% +machines don't like looking at plaid + + + align:start position:0% +machines don't like looking at plaid +they like things that look smooth so it + + align:start position:0% +they like things that look smooth so it + + + align:start position:0% +they like things that look smooth so it +is a practical problem people have found + + align:start position:0% +is a practical problem people have found + + + align:start position:0% +is a practical problem people have found +a ways around it you can CMP the layer + + align:start position:0% +a ways around it you can CMP the layer + + + align:start position:0% +a ways around it you can CMP the layer +and you can remove all the undulations + + align:start position:0% +and you can remove all the undulations + + + align:start position:0% +and you can remove all the undulations +it's not necessarily a big problem but + + align:start position:0% +it's not necessarily a big problem but + + + align:start position:0% +it's not necessarily a big problem but +it it is an issue if you grow the SL and + + align:start position:0% +it it is an issue if you grow the SL and + + + align:start position:0% +it it is an issue if you grow the SL and +geranium too hot it turns out it doesn't + + align:start position:0% +geranium too hot it turns out it doesn't + + + align:start position:0% +geranium too hot it turns out it doesn't +even grow as a planer film it grows as + + align:start position:0% +even grow as a planer film it grows as + + + align:start position:0% +even grow as a planer film it grows as +big little clumps little mountains or + + align:start position:0% +big little clumps little mountains or + + + align:start position:0% +big little clumps little mountains or +isys uh it doesn't wet the surface + + align:start position:0% +isys uh it doesn't wet the surface + + + align:start position:0% +isys uh it doesn't wet the surface +properly and these films are uh these + + align:start position:0% +properly and these films are uh these + + + align:start position:0% +properly and these films are uh these +this type of growth mode is generally + + align:start position:0% +this type of growth mode is generally + + + align:start position:0% +this type of growth mode is generally +considered uh not very useful because + + align:start position:0% +considered uh not very useful because + + + align:start position:0% +considered uh not very useful because +it's it's not really a smooth film um so + + align:start position:0% +it's it's not really a smooth film um so + + + align:start position:0% +it's it's not really a smooth film um so +you cannot grow silicon germanium at too + + align:start position:0% +you cannot grow silicon germanium at too + + + align:start position:0% +you cannot grow silicon germanium at too +high a temperature for a given geranium + + align:start position:0% + + + + align:start position:0% + +fraction what of these fil these relaxed + + align:start position:0% +fraction what of these fil these relaxed + + + align:start position:0% +fraction what of these fil these relaxed +silicon geranium grad buffer layers look + + align:start position:0% +silicon geranium grad buffer layers look + + + align:start position:0% +silicon geranium grad buffer layers look +like I said well they have very few + + align:start position:0% +like I said well they have very few + + + align:start position:0% +like I said well they have very few +defects that thread to the surface + + align:start position:0% +defects that thread to the surface + + + align:start position:0% +defects that thread to the surface +that's indeed true um these are some + + align:start position:0% +that's indeed true um these are some + + + align:start position:0% +that's indeed true um these are some +cross-section temm micrographs of + + align:start position:0% +cross-section temm micrographs of + + + align:start position:0% +cross-section temm micrographs of +relaxed silicon geranium see at 10% uh + + align:start position:0% +relaxed silicon geranium see at 10% uh + + + align:start position:0% +relaxed silicon geranium see at 10% uh +this is the Silicon substrate this is + + align:start position:0% +this is the Silicon substrate this is + + + align:start position:0% +this is the Silicon substrate this is +the graded layer there're are lots of + + align:start position:0% +the graded layer there're are lots of + + + align:start position:0% +the graded layer there're are lots of +dislocations in the graded layer that's + + align:start position:0% +dislocations in the graded layer that's + + + align:start position:0% +dislocations in the graded layer that's +what you want you want dislocations down + + align:start position:0% +what you want you want dislocations down + + + align:start position:0% +what you want you want dislocations down +in the graded layer because you want to + + align:start position:0% +in the graded layer because you want to + + + align:start position:0% +in the graded layer because you want to +relax the lattice primary you want it to + + align:start position:0% +relax the lattice primary you want it to + + + align:start position:0% +relax the lattice primary you want it to +expand to be its equilibrium parameter + + align:start position:0% +expand to be its equilibrium parameter + + + align:start position:0% +expand to be its equilibrium parameter +but what you see is as you get up to the + + align:start position:0% +but what you see is as you get up to the + + + align:start position:0% +but what you see is as you get up to the +surface um if the grade layer is thick + + align:start position:0% +surface um if the grade layer is thick + + + align:start position:0% +surface um if the grade layer is thick +enough into the box layer there are too + + align:start position:0% +enough into the box layer there are too + + + align:start position:0% +enough into the box layer there are too +many dislocations of visible in + + align:start position:0% +many dislocations of visible in + + + align:start position:0% +many dislocations of visible in +cross-section TM again this is up here + + align:start position:0% +cross-section TM again this is up here + + + align:start position:0% +cross-section TM again this is up here +is where you're going to build your + + align:start position:0% +is where you're going to build your + + + align:start position:0% +is where you're going to build your +device so that's what you care about but + + align:start position:0% +device so that's what you care about but + + + align:start position:0% +device so that's what you care about but +if you compare a 10% to a 20 to a 30% + + align:start position:0% +if you compare a 10% to a 20 to a 30% + + + align:start position:0% +if you compare a 10% to a 20 to a 30% +geranium you see a higher and higher Den + + align:start position:0% +geranium you see a higher and higher Den + + + align:start position:0% +geranium you see a higher and higher Den +it of these buried dislocations of + + align:start position:0% +it of these buried dislocations of + + + align:start position:0% +it of these buried dislocations of +course as you increase the geranium + + align:start position:0% +course as you increase the geranium + + + align:start position:0% +course as you increase the geranium +fraction because you have to relieve + + align:start position:0% +fraction because you have to relieve + + + align:start position:0% +fraction because you have to relieve +more lattice mismatch so that the the uh + + align:start position:0% +more lattice mismatch so that the the uh + + + align:start position:0% +more lattice mismatch so that the the uh +the layers get pretty ugly even though + + align:start position:0% +the layers get pretty ugly even though + + + align:start position:0% +the layers get pretty ugly even though +the device is up on top there's still a + + align:start position:0% +the device is up on top there's still a + + + align:start position:0% +the device is up on top there's still a +lot of integration issues you can + + align:start position:0% +lot of integration issues you can + + + align:start position:0% +lot of integration issues you can +imagine trying to make seamoss circuits + + align:start position:0% +imagine trying to make seamoss circuits + + + align:start position:0% +imagine trying to make seamoss circuits +on a substrate that looks like this all + + align:start position:0% +on a substrate that looks like this all + + + align:start position:0% +on a substrate that looks like this all +these buried dislocations are going to + + align:start position:0% +these buried dislocations are going to + + + align:start position:0% +these buried dislocations are going to +worry and they're going to bother the + + align:start position:0% +worry and they're going to bother the + + + align:start position:0% +worry and they're going to bother the +device Engineers because after all we do + + align:start position:0% +device Engineers because after all we do + + + align:start position:0% +device Engineers because after all we do +have seamoss wells we do have deep + + align:start position:0% +have seamoss wells we do have deep + + + align:start position:0% +have seamoss wells we do have deep +Junctions in some of these um some of + + align:start position:0% +Junctions in some of these um some of + + + align:start position:0% +Junctions in some of these um some of +these structures so this this silicon + + align:start position:0% +these structures so this this silicon + + + align:start position:0% +these structures so this this silicon +geranium can affect our my shallow + + align:start position:0% +geranium can affect our my shallow + + + align:start position:0% +geranium can affect our my shallow +trench isolation fabrication formation + + align:start position:0% +trench isolation fabrication formation + + + align:start position:0% +trench isolation fabrication formation +of silicides and the way doens to fuse + + align:start position:0% +of silicides and the way doens to fuse + + + align:start position:0% +of silicides and the way doens to fuse +so it certainly is an + + align:start position:0% + + + + align:start position:0% + +issue in fact there's a whole field of + + align:start position:0% +issue in fact there's a whole field of + + + align:start position:0% +issue in fact there's a whole field of +research going on right now which is the + + align:start position:0% +research going on right now which is the + + + align:start position:0% +research going on right now which is the +study of the diffusion of dopin in silic + + align:start position:0% +study of the diffusion of dopin in silic + + + align:start position:0% +study of the diffusion of dopin in silic +and + + align:start position:0% +and + + + align:start position:0% +and +geranium and I'm showing here on um + + align:start position:0% +geranium and I'm showing here on um + + + align:start position:0% +geranium and I'm showing here on um +slide uh on slide 32 this is some data + + align:start position:0% +slide uh on slide 32 this is some data + + + align:start position:0% +slide uh on slide 32 this is some data +for silicon germanium Alloys with 20% + + align:start position:0% +for silicon germanium Alloys with 20% + + + align:start position:0% +for silicon germanium Alloys with 20% +geranium in them and what we're looking + + align:start position:0% +geranium in them and what we're looking + + + align:start position:0% +geranium in them and what we're looking +at is the diffusivity of different dopin + + align:start position:0% +at is the diffusivity of different dopin + + + align:start position:0% +at is the diffusivity of different dopin +so this is the effective equilibrium + + align:start position:0% +so this is the effective equilibrium + + + align:start position:0% +so this is the effective equilibrium +diffusivity so it's the fusion + + align:start position:0% +diffusivity so it's the fusion + + + align:start position:0% +diffusivity so it's the fusion +coefficient in centime squar per second + + align:start position:0% +coefficient in centime squar per second + + + align:start position:0% +coefficient in centime squar per second +as a function of inverse temperature + + align:start position:0% +as a function of inverse temperature + + + align:start position:0% +as a function of inverse temperature +well the usual kind of arous plot and if + + align:start position:0% +well the usual kind of arous plot and if + + + align:start position:0% +well the usual kind of arous plot and if +you look at Boron so so the dash line + + align:start position:0% +you look at Boron so so the dash line + + + align:start position:0% +you look at Boron so so the dash line +here is for diffusion in Silicon and the + + align:start position:0% +here is for diffusion in Silicon and the + + + align:start position:0% +here is for diffusion in Silicon and the +solid is for diffusion in Silicon + + align:start position:0% +solid is for diffusion in Silicon + + + align:start position:0% +solid is for diffusion in Silicon +geranium if you look at Boron here in + + align:start position:0% +geranium if you look at Boron here in + + + align:start position:0% +geranium if you look at Boron here in +fact in 20% silic and geranium the + + align:start position:0% +fact in 20% silic and geranium the + + + align:start position:0% +fact in 20% silic and geranium the +diffusivity is reduced I'd said before + + align:start position:0% +diffusivity is reduced I'd said before + + + align:start position:0% +diffusivity is reduced I'd said before +factor of 10 looks like more like a + + align:start position:0% +factor of 10 looks like more like a + + + align:start position:0% +factor of 10 looks like more like a +factor of six or so but depending on the + + align:start position:0% +factor of six or so but depending on the + + + align:start position:0% +factor of six or so but depending on the +temperature but so the Boron diffusivity + + align:start position:0% +temperature but so the Boron diffusivity + + + align:start position:0% +temperature but so the Boron diffusivity +goes down uh in solanium which is nice + + align:start position:0% +goes down uh in solanium which is nice + + + align:start position:0% +goes down uh in solanium which is nice +because Bor is a fast diffuser in + + align:start position:0% +because Bor is a fast diffuser in + + + align:start position:0% +because Bor is a fast diffuser in +Silicon but if you look at arsenic this + + align:start position:0% +Silicon but if you look at arsenic this + + + align:start position:0% +Silicon but if you look at arsenic this +is arsenic and silicon the dash line + + align:start position:0% +is arsenic and silicon the dash line + + + align:start position:0% +is arsenic and silicon the dash line +Arsenic and silicon geranium is the + + align:start position:0% +Arsenic and silicon geranium is the + + + align:start position:0% +Arsenic and silicon geranium is the +solid line here with the green arrow so + + align:start position:0% +solid line here with the green arrow so + + + align:start position:0% +solid line here with the green arrow so +the ARs and silicon geranium is + + align:start position:0% +the ARs and silicon geranium is + + + align:start position:0% +the ARs and silicon geranium is +diffusing a lot faster in fact arsic and + + align:start position:0% +diffusing a lot faster in fact arsic and + + + align:start position:0% +diffusing a lot faster in fact arsic and +silicon geranium is diffusing at about + + align:start position:0% +silicon geranium is diffusing at about + + + align:start position:0% +silicon geranium is diffusing at about +the same rate as boron in Silicon geran + + align:start position:0% +the same rate as boron in Silicon geran + + + align:start position:0% +the same rate as boron in Silicon geran +at 20% so we've taken the Boron + + align:start position:0% +at 20% so we've taken the Boron + + + align:start position:0% +at 20% so we've taken the Boron +diffusion coefficient goes down arsenic + + align:start position:0% +diffusion coefficient goes down arsenic + + + align:start position:0% +diffusion coefficient goes down arsenic +which is usually very slow and silicon + + align:start position:0% +which is usually very slow and silicon + + + align:start position:0% +which is usually very slow and silicon +now goes up now they diffuse about + + align:start position:0% +now goes up now they diffuse about + + + align:start position:0% +now goes up now they diffuse about +equally which is kind of interesting you + + align:start position:0% +equally which is kind of interesting you + + + align:start position:0% +equally which is kind of interesting you +can might make some interesting device + + align:start position:0% +can might make some interesting device + + + align:start position:0% +can might make some interesting device +structures when you have symmetric + + align:start position:0% +structures when you have symmetric + + + align:start position:0% +structures when you have symmetric +diffusion coefficients between the n and + + align:start position:0% +diffusion coefficients between the n and + + + align:start position:0% +diffusion coefficients between the n and +the P type doping uh unfortunately what + + align:start position:0% +the P type doping uh unfortunately what + + + align:start position:0% +the P type doping uh unfortunately what +it means is that in in silic and + + align:start position:0% +it means is that in in silic and + + + align:start position:0% +it means is that in in silic and +germanian Mos spets we actually are much + + align:start position:0% +germanian Mos spets we actually are much + + + align:start position:0% +germanian Mos spets we actually are much +more worried about the N type dopa + + align:start position:0% +more worried about the N type dopa + + + align:start position:0% +more worried about the N type dopa +diffusion because it's what's going fast + + align:start position:0% +diffusion because it's what's going fast + + + align:start position:0% +diffusion because it's what's going fast +and we're less worried about the ptype + + align:start position:0% +and we're less worried about the ptype + + + align:start position:0% +and we're less worried about the ptype +dopa diffusion the bn's going slower + + align:start position:0% +dopa diffusion the bn's going slower + + + align:start position:0% +dopa diffusion the bn's going slower +phosphorus doesn't help the situation + + align:start position:0% +phosphorus doesn't help the situation + + + align:start position:0% +phosphorus doesn't help the situation +phosphorus is also enhanced maybe about + + align:start position:0% +phosphorus is also enhanced maybe about + + + align:start position:0% +phosphorus is also enhanced maybe about +a factor it two or three depending on + + align:start position:0% +a factor it two or three depending on + + + align:start position:0% +a factor it two or three depending on +the + + align:start position:0% +the + + + align:start position:0% +the +temperature um so and this line here + + align:start position:0% +temperature um so and this line here + + + align:start position:0% +temperature um so and this line here +gives you an idea roughly of the the + + align:start position:0% +gives you an idea roughly of the the + + + align:start position:0% +gives you an idea roughly of the the +diffusivity of of germanium well this is + + align:start position:0% +diffusivity of of germanium well this is + + + align:start position:0% +diffusivity of of germanium well this is +at a very low geranium fraction um as a + + align:start position:0% +at a very low geranium fraction um as a + + + align:start position:0% +at a very low geranium fraction um as a +function of temperature it's diffusing + + align:start position:0% +function of temperature it's diffusing + + + align:start position:0% +function of temperature it's diffusing +slower than the dopus at least at this + + align:start position:0% +slower than the dopus at least at this + + + align:start position:0% +slower than the dopus at least at this +geranium + + align:start position:0% + + + + align:start position:0% + +fraction so I mentioned to you that + + align:start position:0% +fraction so I mentioned to you that + + + align:start position:0% +fraction so I mentioned to you that +arsenic moves faster in Silicon geranium + + align:start position:0% +arsenic moves faster in Silicon geranium + + + align:start position:0% +arsenic moves faster in Silicon geranium +this is actually a big problem if you're + + align:start position:0% +this is actually a big problem if you're + + + align:start position:0% +this is actually a big problem if you're +trying to make a strain silicon n mosfet + + align:start position:0% +trying to make a strain silicon n mosfet + + + align:start position:0% +trying to make a strain silicon n mosfet +with silicon germanium in the substrate + + align:start position:0% +with silicon germanium in the substrate + + + align:start position:0% +with silicon germanium in the substrate +let's say you're trying to make uh + + align:start position:0% +let's say you're trying to make uh + + + align:start position:0% +let's say you're trying to make uh +shallow Source drains uh so you do you + + align:start position:0% +shallow Source drains uh so you do you + + + align:start position:0% +shallow Source drains uh so you do you +implant 50 k uh at 3 times 10 15th maybe + + align:start position:0% +implant 50 k uh at 3 times 10 15th maybe + + + align:start position:0% +implant 50 k uh at 3 times 10 15th maybe +a typical sour drain uh implant and you + + align:start position:0% +a typical sour drain uh implant and you + + + align:start position:0% +a typical sour drain uh implant and you +en knal it at a th000 + + align:start position:0% +en knal it at a th000 + + + align:start position:0% +en knal it at a th000 +degrees per various times and the dash + + align:start position:0% +degrees per various times and the dash + + + align:start position:0% +degrees per various times and the dash +lines here are for a silicon substrate + + align:start position:0% +lines here are for a silicon substrate + + + align:start position:0% +lines here are for a silicon substrate +uh and the solid are for silicon + + align:start position:0% +uh and the solid are for silicon + + + align:start position:0% +uh and the solid are for silicon +geranium so if you just look at um say + + align:start position:0% +geranium so if you just look at um say + + + align:start position:0% +geranium so if you just look at um say +this dash line here this red dash line + + align:start position:0% +this dash line here this red dash line + + + align:start position:0% +this dash line here this red dash line +you for the Silicon substrate with this + + align:start position:0% +you for the Silicon substrate with this + + + align:start position:0% +you for the Silicon substrate with this +um 202 anal at a th000 you have a + + align:start position:0% +um 202 anal at a th000 you have a + + + align:start position:0% +um 202 anal at a th000 you have a +junction depth about 500 anstrom that's + + align:start position:0% +junction depth about 500 anstrom that's + + + align:start position:0% +junction depth about 500 anstrom that's +perfect for the Silicon geranium + + align:start position:0% +perfect for the Silicon geranium + + + align:start position:0% +perfect for the Silicon geranium +substrate which is the solid line 202 in + + align:start position:0% +substrate which is the solid line 202 in + + + align:start position:0% +substrate which is the solid line 202 in +Neal your Junction depth is more than + + align:start position:0% +Neal your Junction depth is more than + + + align:start position:0% +Neal your Junction depth is more than +twice that point it's it's like 1,200 + + align:start position:0% +twice that point it's it's like 1,200 + + + align:start position:0% +twice that point it's it's like 1,200 +anrs so uh the RS snck and the Silicon + + align:start position:0% +anrs so uh the RS snck and the Silicon + + + align:start position:0% +anrs so uh the RS snck and the Silicon +Terin is going much more rapidly you see + + align:start position:0% +Terin is going much more rapidly you see + + + align:start position:0% +Terin is going much more rapidly you see +this big big shift uh and uh that that's + + align:start position:0% +this big big shift uh and uh that that's + + + align:start position:0% +this big big shift uh and uh that that's +a problem if you use very short inal + + align:start position:0% +a problem if you use very short inal + + + align:start position:0% +a problem if you use very short inal +times you can minimize that difference + + align:start position:0% +times you can minimize that difference + + + align:start position:0% +times you can minimize that difference +but th degrees 1 second is not enough to + + align:start position:0% +but th degrees 1 second is not enough to + + + align:start position:0% +but th degrees 1 second is not enough to +really repair all the damage and to + + align:start position:0% +really repair all the damage and to + + + align:start position:0% +really repair all the damage and to +activate all the dopent so there's a + + align:start position:0% +activate all the dopent so there's a + + + align:start position:0% +activate all the dopent so there's a +very uh interesting issue here is how do + + align:start position:0% +very uh interesting issue here is how do + + + align:start position:0% +very uh interesting issue here is how do +we optimize the uh a kneeling time for + + align:start position:0% +we optimize the uh a kneeling time for + + + align:start position:0% +we optimize the uh a kneeling time for +uh end typ dopen so we get good + + align:start position:0% +uh end typ dopen so we get good + + + align:start position:0% +uh end typ dopen so we get good +activation in the Silicon geranium but + + align:start position:0% +activation in the Silicon geranium but + + + align:start position:0% +activation in the Silicon geranium but +um we don't uh introduce too much + + align:start position:0% +um we don't uh introduce too much + + + align:start position:0% +um we don't uh introduce too much +diffusion otherwise we can't control uh + + align:start position:0% +diffusion otherwise we can't control uh + + + align:start position:0% +diffusion otherwise we can't control uh +control the device + + align:start position:0% + + + + align:start position:0% + +fabrication here's another issue on + + align:start position:0% +fabrication here's another issue on + + + align:start position:0% +fabrication here's another issue on +slide 34 I'm not trying to make silicon + + align:start position:0% +slide 34 I'm not trying to make silicon + + + align:start position:0% +slide 34 I'm not trying to make silicon +geranium look difficult but it is a new + + align:start position:0% +geranium look difficult but it is a new + + + align:start position:0% +geranium look difficult but it is a new +material and a lot of things change uh + + align:start position:0% +material and a lot of things change uh + + + align:start position:0% +material and a lot of things change uh +slide 34 shows you that indeed the + + align:start position:0% +slide 34 shows you that indeed the + + + align:start position:0% +slide 34 shows you that indeed the +geranium itself can diffuse we're + + align:start position:0% +geranium itself can diffuse we're + + + align:start position:0% +geranium itself can diffuse we're +talking about taking a silicon geranium + + align:start position:0% +talking about taking a silicon geranium + + + align:start position:0% +talking about taking a silicon geranium +thick layer and putting a thin layer say + + align:start position:0% +thick layer and putting a thin layer say + + + align:start position:0% +thick layer and putting a thin layer say +100 an strims of strained silicon on it + + align:start position:0% +100 an strims of strained silicon on it + + + align:start position:0% +100 an strims of strained silicon on it +that's my channel okay that sounds fine + + align:start position:0% +that's my channel okay that sounds fine + + + align:start position:0% +that's my channel okay that sounds fine +we can grow that epx but now I need to + + align:start position:0% +we can grow that epx but now I need to + + + align:start position:0% +we can grow that epx but now I need to +implant the sourc tray and enal it at a + + align:start position:0% +implant the sourc tray and enal it at a + + + align:start position:0% +implant the sourc tray and enal it at a +thousand what's going to happen to that + + align:start position:0% +thousand what's going to happen to that + + + align:start position:0% +thousand what's going to happen to that +silicon geranium the geranium and + + align:start position:0% +silicon geranium the geranium and + + + align:start position:0% +silicon geranium the geranium and +silicon Germania well it's going to + + align:start position:0% +silicon Germania well it's going to + + + align:start position:0% +silicon Germania well it's going to +diffuse up into the Silicon once we get + + align:start position:0% +diffuse up into the Silicon once we get + + + align:start position:0% +diffuse up into the Silicon once we get +silicon Jill once we get geranium into + + align:start position:0% +silicon Jill once we get geranium into + + + align:start position:0% +silicon Jill once we get geranium into +the channel that's a no no the electrons + + align:start position:0% +the channel that's a no no the electrons + + + align:start position:0% +the channel that's a no no the electrons +don't like geranium in the channel they + + align:start position:0% +don't like geranium in the channel they + + + align:start position:0% +don't like geranium in the channel they +the electrons can be scattered by the + + align:start position:0% +the electrons can be scattered by the + + + align:start position:0% +the electrons can be scattered by the +geranium Mobility goes way down and your + + align:start position:0% +geranium Mobility goes way down and your + + + align:start position:0% +geranium Mobility goes way down and your +device is ruined you lose a lot of your + + align:start position:0% +device is ruined you lose a lot of your + + + align:start position:0% +device is ruined you lose a lot of your +strain too so you have to keep the + + align:start position:0% +strain too so you have to keep the + + + align:start position:0% +strain too so you have to keep the +geranium out of the channel well it + + align:start position:0% +geranium out of the channel well it + + + align:start position:0% +geranium out of the channel well it +doesn't sound too bad but if you just + + align:start position:0% +doesn't sound too bad but if you just + + + align:start position:0% +doesn't sound too bad but if you just +look at some of the diffusion + + align:start position:0% +look at some of the diffusion + + + align:start position:0% +look at some of the diffusion +coefficients uh in fact U these + + align:start position:0% +coefficients uh in fact U these + + + align:start position:0% +coefficients uh in fact U these +different lines these are measured this + + align:start position:0% +different lines these are measured this + + + align:start position:0% +different lines these are measured this +is the geranium self diffusion in silic + + align:start position:0% +is the geranium self diffusion in silic + + + align:start position:0% +is the geranium self diffusion in silic +geranium Alloys uh for different + + align:start position:0% +geranium Alloys uh for different + + + align:start position:0% +geranium Alloys uh for different +geranium content so this is for silicon + + align:start position:0% +geranium content so this is for silicon + + + align:start position:0% +geranium content so this is for silicon +so this will be silicon self- diffusion + + align:start position:0% +so this will be silicon self- diffusion + + + align:start position:0% +so this will be silicon self- diffusion +this is 10% + + align:start position:0% +this is 10% + + + align:start position:0% +this is 10% +geranium 20% 30 40 and 50 so if you just + + align:start position:0% +geranium 20% 30 40 and 50 so if you just + + + align:start position:0% +geranium 20% 30 40 and 50 so if you just +look at a given temperature say at 9 at + + align:start position:0% +look at a given temperature say at 9 at + + + align:start position:0% +look at a given temperature say at 9 at +950 degrees look at what happening to + + align:start position:0% +950 degrees look at what happening to + + + align:start position:0% +950 degrees look at what happening to +the diffusion coefficient in Silicon uh + + align:start position:0% +the diffusion coefficient in Silicon uh + + + align:start position:0% +the diffusion coefficient in Silicon uh +you know pure silicon gerain is + + align:start position:0% +you know pure silicon gerain is + + + align:start position:0% +you know pure silicon gerain is +diffusing very slowly for a low geranium + + align:start position:0% +diffusing very slowly for a low geranium + + + align:start position:0% +diffusing very slowly for a low geranium +content you know here around 10 Theus + + align:start position:0% +content you know here around 10 Theus + + + align:start position:0% +content you know here around 10 Theus +17th cm squ per second but if you go up + + align:start position:0% +17th cm squ per second but if you go up + + + align:start position:0% +17th cm squ per second but if you go up +to a 40% alloy and diffusivity goes up + + align:start position:0% +to a 40% alloy and diffusivity goes up + + + align:start position:0% +to a 40% alloy and diffusivity goes up +by two orders of magnitude so what this + + align:start position:0% +by two orders of magnitude so what this + + + align:start position:0% +by two orders of magnitude so what this +is saying is basically um you get an + + align:start position:0% +is saying is basically um you get an + + + align:start position:0% +is saying is basically um you get an +exponential increase it looks like in + + align:start position:0% +exponential increase it looks like in + + + align:start position:0% +exponential increase it looks like in +the uh geranium diffus diffusion + + align:start position:0% +the uh geranium diffus diffusion + + + align:start position:0% +the uh geranium diffus diffusion +coefficient as you increase the amount + + align:start position:0% +coefficient as you increase the amount + + + align:start position:0% +coefficient as you increase the amount +of geranium in the alloy so it's that's + + align:start position:0% +of geranium in the alloy so it's that's + + + align:start position:0% +of geranium in the alloy so it's that's +a big issue if you want to do strain + + align:start position:0% +a big issue if you want to do strain + + + align:start position:0% +a big issue if you want to do strain +silicon on 20% you're G to have a + + align:start position:0% +silicon on 20% you're G to have a + + + align:start position:0% +silicon on 20% you're G to have a +silicon geranium you have a certain + + align:start position:0% +silicon geranium you have a certain + + + align:start position:0% +silicon geranium you have a certain +diffusion coefficient if you do it on + + align:start position:0% +diffusion coefficient if you do it on + + + align:start position:0% +diffusion coefficient if you do it on +30% all of a sudden your diffusion + + align:start position:0% +30% all of a sudden your diffusion + + + align:start position:0% +30% all of a sudden your diffusion +coefficient factor of five or so higher + + align:start position:0% +coefficient factor of five or so higher + + + align:start position:0% +coefficient factor of five or so higher +uh so that that's a big issue because + + align:start position:0% +uh so that that's a big issue because + + + align:start position:0% +uh so that that's a big issue because +you don't want the geranium diffusing + + align:start position:0% +you don't want the geranium diffusing + + + align:start position:0% +you don't want the geranium diffusing +into the channel so this data is not + + align:start position:0% +into the channel so this data is not + + + align:start position:0% +into the channel so this data is not +exactly inter diffusion data it needs to + + align:start position:0% +exactly inter diffusion data it needs to + + + align:start position:0% +exactly inter diffusion data it needs to +be that whole problem needs to be worked + + align:start position:0% +be that whole problem needs to be worked + + + align:start position:0% +be that whole problem needs to be worked +out but um inter diffusion is definitely + + align:start position:0% +out but um inter diffusion is definitely + + + align:start position:0% +out but um inter diffusion is definitely +observed for like a th000 degrees 10 + + align:start position:0% +observed for like a th000 degrees 10 + + + align:start position:0% +observed for like a th000 degrees 10 +seconds at 20% so that that's a no no so + + align:start position:0% +seconds at 20% so that that's a no no so + + + align:start position:0% +seconds at 20% so that that's a no no so +that's that's going to be a big issue + + align:start position:0% +that's that's going to be a big issue + + + align:start position:0% +that's that's going to be a big issue +and how we're going to activate Source + + align:start position:0% +and how we're going to activate Source + + + align:start position:0% +and how we're going to activate Source +strains in those kind of + + align:start position:0% + + + + align:start position:0% + +structures that's an interesting + + align:start position:0% +structures that's an interesting + + + align:start position:0% +structures that's an interesting +research uh area um you might be saying + + align:start position:0% +research uh area um you might be saying + + + align:start position:0% +research uh area um you might be saying +well what is the mechanism uh of + + align:start position:0% +well what is the mechanism uh of + + + align:start position:0% +well what is the mechanism uh of +diffusion of germanium in in Silicon + + align:start position:0% +diffusion of germanium in in Silicon + + + align:start position:0% +diffusion of germanium in in Silicon +anyway actually it's not really known + + align:start position:0% +anyway actually it's not really known + + + align:start position:0% +anyway actually it's not really known +and this is a on page 35 an example uh + + align:start position:0% +and this is a on page 35 an example uh + + + align:start position:0% +and this is a on page 35 an example uh +of people are just trying to get a + + align:start position:0% +of people are just trying to get a + + + align:start position:0% +of people are just trying to get a +handle on this this was published about + + align:start position:0% +handle on this this was published about + + + align:start position:0% +handle on this this was published about +about a year and a half ago um and + + align:start position:0% +about a year and a half ago um and + + + align:start position:0% +about a year and a half ago um and +people did uh this particular experiment + + align:start position:0% +people did uh this particular experiment + + + align:start position:0% +people did uh this particular experiment +they did a process where they had + + align:start position:0% +they did a process where they had + + + align:start position:0% +they did a process where they had +strained silicon on relaxed silicon + + align:start position:0% +strained silicon on relaxed silicon + + + align:start position:0% +strained silicon on relaxed silicon +germanian and they did an anal in a + + align:start position:0% +germanian and they did an anal in a + + + align:start position:0% +germanian and they did an anal in a +rapid thermal analer where they put in + + align:start position:0% +rapid thermal analer where they put in + + + align:start position:0% +rapid thermal analer where they put in +ammonia so they're doing rapid thermal + + align:start position:0% +ammonia so they're doing rapid thermal + + + align:start position:0% +ammonia so they're doing rapid thermal +nitridation so what do we know about + + align:start position:0% +nitridation so what do we know about + + + align:start position:0% +nitridation so what do we know about +nitridation well nitridation we believe + + align:start position:0% +nitridation well nitridation we believe + + + align:start position:0% +nitridation well nitridation we believe +injects vacancies right that's when we + + align:start position:0% +injects vacancies right that's when we + + + align:start position:0% +injects vacancies right that's when we +use it so in the samples that were + + align:start position:0% +use it so in the samples that were + + + align:start position:0% +use it so in the samples that were +nitrided the geranium diffused right + + align:start position:0% +nitrided the geranium diffused right + + + align:start position:0% +nitrided the geranium diffused right +through the strain silic all the way to + + align:start position:0% +through the strain silic all the way to + + + align:start position:0% +through the strain silic all the way to +the surface and The Sims profile for the + + align:start position:0% +the surface and The Sims profile for the + + + align:start position:0% +the surface and The Sims profile for the +the blue here shows that geranium went + + align:start position:0% +the blue here shows that geranium went + + + align:start position:0% +the blue here shows that geranium went +right through that that 100 anstrom + + align:start position:0% +right through that that 100 anstrom + + + align:start position:0% +right through that that 100 anstrom +layer it was gone um the red line is for + + align:start position:0% +layer it was gone um the red line is for + + + align:start position:0% +layer it was gone um the red line is for +the geranium that was in NE inner + + align:start position:0% +the geranium that was in NE inner + + + align:start position:0% +the geranium that was in NE inner +ambient it diffused a little bit at this + + align:start position:0% +ambient it diffused a little bit at this + + + align:start position:0% +ambient it diffused a little bit at this +during this rapid thermal knel but uh + + align:start position:0% +during this rapid thermal knel but uh + + + align:start position:0% +during this rapid thermal knel but uh +you can ignore the surface Peak because + + align:start position:0% +you can ignore the surface Peak because + + + align:start position:0% +you can ignore the surface Peak because +that's sort of a Sims artifact but at + + align:start position:0% +that's sort of a Sims artifact but at + + + align:start position:0% +that's sort of a Sims artifact but at +least it didn't go all the way so this + + align:start position:0% +least it didn't go all the way so this + + + align:start position:0% +least it didn't go all the way so this +is a very preliminary result and it has + + align:start position:0% +is a very preliminary result and it has + + + align:start position:0% +is a very preliminary result and it has +to be repeated but it sort of indicates + + align:start position:0% +to be repeated but it sort of indicates + + + align:start position:0% +to be repeated but it sort of indicates +that processes that inject vacancies + + align:start position:0% +that processes that inject vacancies + + + align:start position:0% +that processes that inject vacancies +probably should be avoided if you're + + align:start position:0% +probably should be avoided if you're + + + align:start position:0% +probably should be avoided if you're +trying to control the diffusion of + + align:start position:0% +trying to control the diffusion of + + + align:start position:0% +trying to control the diffusion of +geran uh and so um so there are a lot of + + align:start position:0% +geran uh and so um so there are a lot of + + + align:start position:0% +geran uh and so um so there are a lot of +interest in doing processes to inject + + align:start position:0% +interest in doing processes to inject + + + align:start position:0% +interest in doing processes to inject +intials inject vacancies all the same + + align:start position:0% +intials inject vacancies all the same + + + align:start position:0% +intials inject vacancies all the same +kind of process the uh tests that have + + align:start position:0% +kind of process the uh tests that have + + + align:start position:0% +kind of process the uh tests that have +done in Silicon can now be done in + + align:start position:0% +done in Silicon can now be done in + + + align:start position:0% +done in Silicon can now be done in +strain silicon on Silicon geranium to + + align:start position:0% +strain silicon on Silicon geranium to + + + align:start position:0% +strain silicon on Silicon geranium to +see how the geranium diffuses or even + + align:start position:0% +see how the geranium diffuses or even + + + align:start position:0% +see how the geranium diffuses or even +how the dopin + + align:start position:0% + + + + align:start position:0% + +diffuse I want to say a little bit now + + align:start position:0% +diffuse I want to say a little bit now + + + align:start position:0% +diffuse I want to say a little bit now +about these mod FS on insulator because + + align:start position:0% +about these mod FS on insulator because + + + align:start position:0% +about these mod FS on insulator because +I've talked a little bit about how the + + align:start position:0% +I've talked a little bit about how the + + + align:start position:0% +I've talked a little bit about how the +Silicon geranium is becoming a problem + + align:start position:0% +Silicon geranium is becoming a problem + + + align:start position:0% +Silicon geranium is becoming a problem +how can we get around some of these + + align:start position:0% +how can we get around some of these + + + align:start position:0% +how can we get around some of these +Problem by doing strain silicon on + + align:start position:0% + + + + align:start position:0% + +insulator well on page 37 I'm showing an + + align:start position:0% +insulator well on page 37 I'm showing an + + + align:start position:0% +insulator well on page 37 I'm showing an +example of a potential thing you might + + align:start position:0% +example of a potential thing you might + + + align:start position:0% +example of a potential thing you might +be thinking of well let's say we could + + align:start position:0% +be thinking of well let's say we could + + + align:start position:0% +be thinking of well let's say we could +get rid of if we go back here let me go + + align:start position:0% +get rid of if we go back here let me go + + + align:start position:0% +get rid of if we go back here let me go +back a few slides and uh I just look at + + align:start position:0% +back a few slides and uh I just look at + + + align:start position:0% +back a few slides and uh I just look at +this on on slide 31 this ugly looking + + align:start position:0% +this on on slide 31 this ugly looking + + + align:start position:0% +this on on slide 31 this ugly looking +thing with all these dislocations and + + align:start position:0% +thing with all these dislocations and + + + align:start position:0% +thing with all these dislocations and +that thick silicon germanium substrate I + + align:start position:0% +that thick silicon germanium substrate I + + + align:start position:0% +that thick silicon germanium substrate I +need them to relax The Strain so I can + + align:start position:0% +need them to relax The Strain so I can + + + align:start position:0% +need them to relax The Strain so I can +grow a thin layer of strain silicon on + + align:start position:0% +grow a thin layer of strain silicon on + + + align:start position:0% +grow a thin layer of strain silicon on +top but I don't really need them once + + align:start position:0% +top but I don't really need them once + + + align:start position:0% +top but I don't really need them once +the strain is relaxed so the idea was + + align:start position:0% +the strain is relaxed so the idea was + + + align:start position:0% +the strain is relaxed so the idea was +what if you could take this layer the + + align:start position:0% +what if you could take this layer the + + + align:start position:0% +what if you could take this layer the +top portion looks pretty good if you + + align:start position:0% +top portion looks pretty good if you + + + align:start position:0% +top portion looks pretty good if you +could take this whole layer and bond it + + align:start position:0% +could take this whole layer and bond it + + + align:start position:0% +could take this whole layer and bond it +to another wafer and then get rid of + + align:start position:0% +to another wafer and then get rid of + + + align:start position:0% +to another wafer and then get rid of +etch away all the dislocated material + + align:start position:0% +etch away all the dislocated material + + + align:start position:0% +etch away all the dislocated material +and you'd have relaxed silicon geranium + + align:start position:0% +and you'd have relaxed silicon geranium + + + align:start position:0% +and you'd have relaxed silicon geranium +on insulator for example and all this + + align:start position:0% +on insulator for example and all this + + + align:start position:0% +on insulator for example and all this +dislocation material would have been + + align:start position:0% +dislocation material would have been + + + align:start position:0% +dislocation material would have been +etched off or maybe removed by a smart + + align:start position:0% +etched off or maybe removed by a smart + + + align:start position:0% +etched off or maybe removed by a smart +cut like process uh I think some of you + + align:start position:0% +cut like process uh I think some of you + + + align:start position:0% +cut like process uh I think some of you +are studying smart cut we talked about a + + align:start position:0% +are studying smart cut we talked about a + + + align:start position:0% +are studying smart cut we talked about a +little bit we talked about SOI formation + + align:start position:0% +little bit we talked about SOI formation + + + align:start position:0% +little bit we talked about SOI formation +so in fact that's what this cartoon on + + align:start position:0% +so in fact that's what this cartoon on + + + align:start position:0% +so in fact that's what this cartoon on +slide 20 37 shows where you might have a + + align:start position:0% +slide 20 37 shows where you might have a + + + align:start position:0% +slide 20 37 shows where you might have a +thin layer of relaxed silic and geranium + + align:start position:0% +thin layer of relaxed silic and geranium + + + align:start position:0% +thin layer of relaxed silic and geranium +that has been generated by growing a + + align:start position:0% +that has been generated by growing a + + + align:start position:0% +that has been generated by growing a +thick layer and bonding it on uh and + + align:start position:0% +thick layer and bonding it on uh and + + + align:start position:0% +thick layer and bonding it on uh and +then you could grow strain silicon on + + align:start position:0% +then you could grow strain silicon on + + + align:start position:0% +then you could grow strain silicon on +top and make your your n moss and your P + + align:start position:0% +top and make your your n moss and your P + + + align:start position:0% +top and make your your n moss and your P +Moss uh that way so this is one idea + + align:start position:0% +Moss uh that way so this is one idea + + + align:start position:0% +Moss uh that way so this is one idea +that people have been pursuing uh to uh + + align:start position:0% +that people have been pursuing uh to uh + + + align:start position:0% +that people have been pursuing uh to uh +to get around some of those dislocation + + align:start position:0% +to get around some of those dislocation + + + align:start position:0% +to get around some of those dislocation +issues in fact on slide 38 if you're + + align:start position:0% +issues in fact on slide 38 if you're + + + align:start position:0% +issues in fact on slide 38 if you're +interested I've listed a number of + + align:start position:0% +interested I've listed a number of + + + align:start position:0% +interested I've listed a number of +different references here on how people + + align:start position:0% +different references here on how people + + + align:start position:0% +different references here on how people +are trying to form relax silicon + + align:start position:0% +are trying to form relax silicon + + + align:start position:0% +are trying to form relax silicon +geranium on insulator it turns out there + + align:start position:0% +geranium on insulator it turns out there + + + align:start position:0% +geranium on insulator it turns out there +are a lot of different processes not + + align:start position:0% +are a lot of different processes not + + + align:start position:0% +are a lot of different processes not +just the bonding process there is a + + align:start position:0% +just the bonding process there is a + + + align:start position:0% +just the bonding process there is a +simox like process where people grow + + align:start position:0% +simox like process where people grow + + + align:start position:0% +simox like process where people grow +silicon geranium on silicon epx and then + + align:start position:0% +silicon geranium on silicon epx and then + + + align:start position:0% +silicon geranium on silicon epx and then +they ion implant the oxygen that's + + align:start position:0% +they ion implant the oxygen that's + + + align:start position:0% +they ion implant the oxygen that's +exactly how SOI is made it's SOI they + + align:start position:0% +exactly how SOI is made it's SOI they + + + align:start position:0% +exactly how SOI is made it's SOI they +ion implant into pure silicon here they + + align:start position:0% +ion implant into pure silicon here they + + + align:start position:0% +ion implant into pure silicon here they +I implant the oxygen into a silicon + + align:start position:0% +I implant the oxygen into a silicon + + + align:start position:0% +I implant the oxygen into a silicon +geranium layer so it's a simox like + + align:start position:0% +geranium layer so it's a simox like + + + align:start position:0% +geranium layer so it's a simox like +process Toshiba has has talked about + + align:start position:0% +process Toshiba has has talked about + + + align:start position:0% +process Toshiba has has talked about +that there's some problems though uh for + + align:start position:0% +that there's some problems though uh for + + + align:start position:0% +that there's some problems though uh for +for high geranium contents of above + + align:start position:0% +for high geranium contents of above + + + align:start position:0% +for high geranium contents of above +about 15% it doesn't work very well um + + align:start position:0% +about 15% it doesn't work very well um + + + align:start position:0% +about 15% it doesn't work very well um +there's another very interesting + + align:start position:0% +there's another very interesting + + + align:start position:0% +there's another very interesting +technique um also came out of Toshiba + + align:start position:0% +technique um also came out of Toshiba + + + align:start position:0% +technique um also came out of Toshiba +called geranium condensation they + + align:start position:0% +called geranium condensation they + + + align:start position:0% +called geranium condensation they +actually start with Ani wafer they start + + align:start position:0% +actually start with Ani wafer they start + + + align:start position:0% +actually start with Ani wafer they start +with a wafer you buy from a commercial + + align:start position:0% +with a wafer you buy from a commercial + + + align:start position:0% +with a wafer you buy from a commercial +vender with a silicon on insulator they + + align:start position:0% +vender with a silicon on insulator they + + + align:start position:0% +vender with a silicon on insulator they +epically grow a thin layer of silicon + + align:start position:0% +epically grow a thin layer of silicon + + + align:start position:0% +epically grow a thin layer of silicon +geranium with a relatively low gerian + + align:start position:0% +geranium with a relatively low gerian + + + align:start position:0% +geranium with a relatively low gerian +content and they oxidize the whole thing + + align:start position:0% +content and they oxidize the whole thing + + + align:start position:0% +content and they oxidize the whole thing +and turns out in the oxidation the geran + + align:start position:0% +and turns out in the oxidation the geran + + + align:start position:0% +and turns out in the oxidation the geran +the snow plow forward into the layer um + + align:start position:0% +the snow plow forward into the layer um + + + align:start position:0% +the snow plow forward into the layer um +and the layer relaxes so they end up + + align:start position:0% +and the layer relaxes so they end up + + + align:start position:0% +and the layer relaxes so they end up +with a higher germanium content after + + align:start position:0% +with a higher germanium content after + + + align:start position:0% +with a higher germanium content after +oxidation and they have the layer + + align:start position:0% +oxidation and they have the layer + + + align:start position:0% +oxidation and they have the layer +originally strain silicon geranium layer + + align:start position:0% +originally strain silicon geranium layer + + + align:start position:0% +originally strain silicon geranium layer +ends up relaxing by form by the + + align:start position:0% +ends up relaxing by form by the + + + align:start position:0% +ends up relaxing by form by the +oxidation process and very high + + align:start position:0% +oxidation process and very high + + + align:start position:0% +oxidation process and very high +temperatures so that seems to be + + align:start position:0% +temperatures so that seems to be + + + align:start position:0% +temperatures so that seems to be +interesting uh there's a very similar + + align:start position:0% +interesting uh there's a very similar + + + align:start position:0% +interesting uh there's a very similar +technique uh called melt solidification + + align:start position:0% +technique uh called melt solidification + + + align:start position:0% +technique uh called melt solidification +by by another group uh and the bond and + + align:start position:0% +by by another group uh and the bond and + + + align:start position:0% +by by another group uh and the bond and +Edge back is what I mentioned before you + + align:start position:0% +Edge back is what I mentioned before you + + + align:start position:0% +Edge back is what I mentioned before you +grow The Strain Sil the relaxed silicon + + align:start position:0% +grow The Strain Sil the relaxed silicon + + + align:start position:0% +grow The Strain Sil the relaxed silicon +geranium Bond it to an oxide wafer and + + align:start position:0% +geranium Bond it to an oxide wafer and + + + align:start position:0% +geranium Bond it to an oxide wafer and +itch it back or smart cut it + + align:start position:0% +itch it back or smart cut it + + + align:start position:0% +itch it back or smart cut it +off um this is just that same process on + + align:start position:0% +off um this is just that same process on + + + align:start position:0% +off um this is just that same process on +slide 39 it won't go in great detail but + + align:start position:0% +slide 39 it won't go in great detail but + + + align:start position:0% +slide 39 it won't go in great detail but +you can imagine by bonding and selective + + align:start position:0% +you can imagine by bonding and selective + + + align:start position:0% +you can imagine by bonding and selective +etching uh you grow your graded silicon + + align:start position:0% +etching uh you grow your graded silicon + + + align:start position:0% +etching uh you grow your graded silicon +germanium relaxed layer you grow your + + align:start position:0% +germanium relaxed layer you grow your + + + align:start position:0% +germanium relaxed layer you grow your +relaxed cap and then uh you um flip it + + align:start position:0% +relaxed cap and then uh you um flip it + + + align:start position:0% +relaxed cap and then uh you um flip it +over and bond it to an oxidized handle + + align:start position:0% +over and bond it to an oxidized handle + + + align:start position:0% +over and bond it to an oxidized handle +wafer just like you would in in a bond + + align:start position:0% +wafer just like you would in in a bond + + + align:start position:0% +wafer just like you would in in a bond +and itch SOI and then you etch + + align:start position:0% +and itch SOI and then you etch + + + align:start position:0% +and itch SOI and then you etch +everything back and you end up with just + + align:start position:0% +everything back and you end up with just + + + align:start position:0% +everything back and you end up with just +relaxed silicon Germania after you've + + align:start position:0% +relaxed silicon Germania after you've + + + align:start position:0% +relaxed silicon Germania after you've +CMP relax silicon geranium on + + align:start position:0% +CMP relax silicon geranium on + + + align:start position:0% +CMP relax silicon geranium on +insulator so that's a technique that's + + align:start position:0% +insulator so that's a technique that's + + + align:start position:0% +insulator so that's a technique that's +uh being pursued to form relax silicon + + align:start position:0% +uh being pursued to form relax silicon + + + align:start position:0% +uh being pursued to form relax silicon +germanium on insulator and then you can + + align:start position:0% +germanium on insulator and then you can + + + align:start position:0% +germanium on insulator and then you can +grow strain silicon + + align:start position:0% +grow strain silicon + + + align:start position:0% +grow strain silicon +afterwards um you can also do bonding uh + + align:start position:0% +afterwards um you can also do bonding uh + + + align:start position:0% +afterwards um you can also do bonding uh +and hydrogen induced delamination or + + align:start position:0% +and hydrogen induced delamination or + + + align:start position:0% +and hydrogen induced delamination or +smart cut uh if you we've studied smart + + align:start position:0% +smart cut uh if you we've studied smart + + + align:start position:0% +smart cut uh if you we've studied smart +cut for silicon here we start with a + + align:start position:0% +cut for silicon here we start with a + + + align:start position:0% +cut for silicon here we start with a +relaxed silicon germanium epilayer we + + align:start position:0% +relaxed silicon germanium epilayer we + + + align:start position:0% +relaxed silicon germanium epilayer we +ion a plant with hydrogen and at the + + align:start position:0% +ion a plant with hydrogen and at the + + + align:start position:0% +ion a plant with hydrogen and at the +peak of the hydrogen bubbles + + align:start position:0% +peak of the hydrogen bubbles + + + align:start position:0% +peak of the hydrogen bubbles +form so after we've done the bonding + + align:start position:0% +form so after we've done the bonding + + + align:start position:0% +form so after we've done the bonding +we heat it up and those bubbles end up + + align:start position:0% +we heat it up and those bubbles end up + + + align:start position:0% +we heat it up and those bubbles end up +cleaving at all you get the delamination + + align:start position:0% +cleaving at all you get the delamination + + + align:start position:0% +cleaving at all you get the delamination +process is exactly analogous to what + + align:start position:0% +process is exactly analogous to what + + + align:start position:0% +process is exactly analogous to what +happens in s SOI Fab and now you have + + align:start position:0% +happens in s SOI Fab and now you have + + + align:start position:0% +happens in s SOI Fab and now you have +silicon geranium on insulator of course + + align:start position:0% +silicon geranium on insulator of course + + + align:start position:0% +silicon geranium on insulator of course +it has to be polished and smoothed but + + align:start position:0% +it has to be polished and smoothed but + + + align:start position:0% +it has to be polished and smoothed but +it it is a way form that + + align:start position:0% + + + + align:start position:0% + +material uh I'll skip through this at + + align:start position:0% +material uh I'll skip through this at + + + align:start position:0% +material uh I'll skip through this at +this point because what basically it + + align:start position:0% +this point because what basically it + + + align:start position:0% +this point because what basically it +shows when you make that and you make a + + align:start position:0% +shows when you make that and you make a + + + align:start position:0% +shows when you make that and you make a +strain silicon mosfet you get the same + + align:start position:0% +strain silicon mosfet you get the same + + + align:start position:0% +strain silicon mosfet you get the same +Mobility that you that people have seen + + align:start position:0% +Mobility that you that people have seen + + + align:start position:0% +Mobility that you that people have seen +in the + + align:start position:0% +in the + + + align:start position:0% +in the +past uh again I'll skip that interest of + + align:start position:0% +past uh again I'll skip that interest of + + + align:start position:0% +past uh again I'll skip that interest of +and and what I want to end up with is + + align:start position:0% +and and what I want to end up with is + + + align:start position:0% +and and what I want to end up with is +there's another approach people thought + + align:start position:0% +there's another approach people thought + + + align:start position:0% +there's another approach people thought +well why don't you just transfer the + + align:start position:0% +well why don't you just transfer the + + + align:start position:0% +well why don't you just transfer the +strain silicon layer itself why do you + + align:start position:0% +strain silicon layer itself why do you + + + align:start position:0% +strain silicon layer itself why do you +even have to transfer once you grow the + + align:start position:0% +even have to transfer once you grow the + + + align:start position:0% +even have to transfer once you grow the +relaxed silicon germanium you can grow + + align:start position:0% +relaxed silicon germanium you can grow + + + align:start position:0% +relaxed silicon germanium you can grow +strain silicon on top of it bond that to + + align:start position:0% +strain silicon on top of it bond that to + + + align:start position:0% +strain silicon on top of it bond that to +oxide and then remove everything except + + align:start position:0% +oxide and then remove everything except + + + align:start position:0% +oxide and then remove everything except +the strain silicon and if the Silicon if + + align:start position:0% +the strain silicon and if the Silicon if + + + align:start position:0% +the strain silicon and if the Silicon if +the strain remains then you have + + align:start position:0% +the strain remains then you have + + + align:start position:0% +the strain remains then you have +strained silicon directly on the + + align:start position:0% +strained silicon directly on the + + + align:start position:0% +strained silicon directly on the +insulator you remove the Silicon + + align:start position:0% +insulator you remove the Silicon + + + align:start position:0% +insulator you remove the Silicon +geranium completely so you don't have to + + align:start position:0% +geranium completely so you don't have to + + + align:start position:0% +geranium completely so you don't have to +worry about silicon geranium diffusion + + align:start position:0% +worry about silicon geranium diffusion + + + align:start position:0% +worry about silicon geranium diffusion +and and diffusion of do silicon + + align:start position:0% +and and diffusion of do silicon + + + align:start position:0% +and and diffusion of do silicon +germanium and all that so this is an + + align:start position:0% +germanium and all that so this is an + + + align:start position:0% +germanium and all that so this is an +ultra thin strain silicon directly an + + align:start position:0% +ultra thin strain silicon directly an + + + align:start position:0% +ultra thin strain silicon directly an +insulator sort of concept this is just a + + align:start position:0% +insulator sort of concept this is just a + + + align:start position:0% +insulator sort of concept this is just a +cartoon um it's actually been + + align:start position:0% +cartoon um it's actually been + + + align:start position:0% +cartoon um it's actually been +demonstrated fairly + + align:start position:0% +demonstrated fairly + + + align:start position:0% +demonstrated fairly +recently uh here at MIT on page 44 in + + align:start position:0% +recently uh here at MIT on page 44 in + + + align:start position:0% +recently uh here at MIT on page 44 in +fact this is the process that was used a + + align:start position:0% +fact this is the process that was used a + + + align:start position:0% +fact this is the process that was used a +very complicated stack of EP layers was + + align:start position:0% +very complicated stack of EP layers was + + + align:start position:0% +very complicated stack of EP layers was +grown but the important thing is the top + + align:start position:0% +grown but the important thing is the top + + + align:start position:0% +grown but the important thing is the top +of the stack was strained silicon and + + align:start position:0% +of the stack was strained silicon and + + + align:start position:0% +of the stack was strained silicon and +that whole stack was bonded to an + + align:start position:0% +that whole stack was bonded to an + + + align:start position:0% +that whole stack was bonded to an +oxidized silicon wafer and then + + align:start position:0% +oxidized silicon wafer and then + + + align:start position:0% +oxidized silicon wafer and then +everything was removed by selective + + align:start position:0% +everything was removed by selective + + + align:start position:0% +everything was removed by selective +etching so when you're done all you have + + align:start position:0% +etching so when you're done all you have + + + align:start position:0% +etching so when you're done all you have +left is strain silicon directly on the + + align:start position:0% +left is strain silicon directly on the + + + align:start position:0% +left is strain silicon directly on the +oxide uh and you use Edge EDG stop + + align:start position:0% +oxide uh and you use Edge EDG stop + + + align:start position:0% +oxide uh and you use Edge EDG stop +layers so you can Edge back the entire + + align:start position:0% +layers so you can Edge back the entire + + + align:start position:0% +layers so you can Edge back the entire +wafer and just leave strained silicon + + align:start position:0% +wafer and just leave strained silicon + + + align:start position:0% +wafer and just leave strained silicon +behind and in fact on page 45 what you + + align:start position:0% +behind and in fact on page 45 what you + + + align:start position:0% +behind and in fact on page 45 what you +see is that uh the strained silicon is + + align:start position:0% +see is that uh the strained silicon is + + + align:start position:0% +see is that uh the strained silicon is +bonded to the oxide um it's low defect + + align:start position:0% +bonded to the oxide um it's low defect + + + align:start position:0% +bonded to the oxide um it's low defect +density material and if you do Ramon + + align:start position:0% +density material and if you do Ramon + + + align:start position:0% +density material and if you do Ramon +scattering The Strain remains even after + + align:start position:0% +scattering The Strain remains even after + + + align:start position:0% +scattering The Strain remains even after +you remove the Silicon geranium and we + + align:start position:0% +you remove the Silicon geranium and we + + + align:start position:0% +you remove the Silicon geranium and we +knal it at high temperatures uh even up + + align:start position:0% +knal it at high temperatures uh even up + + + align:start position:0% +knal it at high temperatures uh even up +to 1,000° the strain doesn't go away so + + align:start position:0% +to 1,000° the strain doesn't go away so + + + align:start position:0% +to 1,000° the strain doesn't go away so +the bond is very strong + + align:start position:0% +the bond is very strong + + + align:start position:0% +the bond is very strong +so now you have strain soen directly on + + align:start position:0% +so now you have strain soen directly on + + + align:start position:0% +so now you have strain soen directly on +insulator looks just like SOI you can + + align:start position:0% +insulator looks just like SOI you can + + + align:start position:0% +insulator looks just like SOI you can +process just like SOI but the strain is + + align:start position:0% +process just like SOI but the strain is + + + align:start position:0% +process just like SOI but the strain is +already built in you don't have any + + align:start position:0% +already built in you don't have any + + + align:start position:0% +already built in you don't have any +geran that you need to worry + + align:start position:0% +geran that you need to worry + + + align:start position:0% +geran that you need to worry +about so I think that's going to be a + + align:start position:0% +about so I think that's going to be a + + + align:start position:0% +about so I think that's going to be a +pretty interesting area for the Future + + align:start position:0% +pretty interesting area for the Future + + + align:start position:0% +pretty interesting area for the Future +these uh just yesterday I read in the + + align:start position:0% +these uh just yesterday I read in the + + + align:start position:0% +these uh just yesterday I read in the +paper that it been announced that a + + align:start position:0% +paper that it been announced that a + + + align:start position:0% +paper that it been announced that a +company called soy is now manufacturing + + align:start position:0% +company called soy is now manufacturing + + + align:start position:0% +company called soy is now manufacturing +300 mm strain silicon directly on + + align:start position:0% +300 mm strain silicon directly on + + + align:start position:0% +300 mm strain silicon directly on +insulator SSD and uh once it becomes + + align:start position:0% +insulator SSD and uh once it becomes + + + align:start position:0% +insulator SSD and uh once it becomes +available 300 millimeter a lot of + + align:start position:0% +available 300 millimeter a lot of + + + align:start position:0% +available 300 millimeter a lot of +companies will be able to use it for + + align:start position:0% +companies will be able to use it for + + + align:start position:0% +companies will be able to use it for +their um for their production so that's + + align:start position:0% +their um for their production so that's + + + align:start position:0% +their um for their production so that's +about all I have to say on that I know I + + align:start position:0% +about all I have to say on that I know I + + + align:start position:0% +about all I have to say on that I know I +need to leave you time I'm glad I see + + align:start position:0% +need to leave you time I'm glad I see + + + align:start position:0% +need to leave you time I'm glad I see +the uh the survey is here I hope you + + align:start position:0% +the uh the survey is here I hope you + + + align:start position:0% +the uh the survey is here I hope you +haven't been waiting outside but uh + + align:start position:0% +haven't been waiting outside but uh + + + align:start position:0% +haven't been waiting outside but uh +please take uh 10 minutes or so and go + + align:start position:0% +please take uh 10 minutes or so and go + + + align:start position:0% +please take uh 10 minutes or so and go +ahead and fill out the class evaluation + + align:start position:0% +ahead and fill out the class evaluation + + + align:start position:0% +ahead and fill out the class evaluation +the course evaluation + + align:start position:0% + + + + align:start position:0% + +survey \ No newline at end of file diff --git a/n25tsUQb3vo.txt b/n25tsUQb3vo.txt new file mode 100644 index 0000000000000000000000000000000000000000..30fdb25a7f28a744f082350587e54392298efe90 --- /dev/null +++ b/n25tsUQb3vo.txt @@ -0,0 +1,16307 @@ +align:start position:0% + +The following content is provided under + + align:start position:0% +The following content is provided under + + + align:start position:0% +The following content is provided under +a Creative Common license. Your support + + align:start position:0% +a Creative Common license. Your support + + + align:start position:0% +a Creative Common license. Your support +will help MIT Open Courseware continue + + align:start position:0% +will help MIT Open Courseware continue + + + align:start position:0% +will help MIT Open Courseware continue +to offer high-quality educational + + align:start position:0% +to offer high-quality educational + + + align:start position:0% +to offer high-quality educational +resources for free. To make a donation + + align:start position:0% +resources for free. To make a donation + + + align:start position:0% +resources for free. To make a donation +or view additional materials from + + align:start position:0% +or view additional materials from + + + align:start position:0% +or view additional materials from +hundreds of MIT courses, visit MIT Open + + align:start position:0% +hundreds of MIT courses, visit MIT Open + + + align:start position:0% +hundreds of MIT courses, visit MIT Open +Courseware at ocw.mmit.edu. + + align:start position:0% + + + + align:start position:0% + +Uh today we're going to dive into cost, + + align:start position:0% +Uh today we're going to dive into cost, + + + align:start position:0% +Uh today we're going to dive into cost, +price, markets, and support mechanisms. + + align:start position:0% +price, markets, and support mechanisms. + + + align:start position:0% +price, markets, and support mechanisms. +The support mechanisms, otherwise known + + align:start position:0% +The support mechanisms, otherwise known + + + align:start position:0% +The support mechanisms, otherwise known +as subsidies, right? Um so uh this is + + align:start position:0% +as subsidies, right? Um so uh this is + + + align:start position:0% +as subsidies, right? Um so uh this is +lecture 18. We're approaching the end of + + align:start position:0% +lecture 18. We're approaching the end of + + + align:start position:0% +lecture 18. We're approaching the end of +our course. Actually, we have about we + + align:start position:0% +our course. Actually, we have about we + + + align:start position:0% +our course. Actually, we have about we +have a handful of lectures left and then + + align:start position:0% +have a handful of lectures left and then + + + align:start position:0% +have a handful of lectures left and then +we um and then we uh go our separate + + align:start position:0% +we um and then we uh go our separate + + + align:start position:0% +we um and then we uh go our separate +ways. the um this particular lecture + + align:start position:0% +ways. the um this particular lecture + + + align:start position:0% +ways. the um this particular lecture +will be followed up not this Thursday + + align:start position:0% +will be followed up not this Thursday + + + align:start position:0% +will be followed up not this Thursday +but the following Thursday. Uh we'll + + align:start position:0% +but the following Thursday. Uh we'll + + + align:start position:0% +but the following Thursday. Uh we'll +have a guest speaker come in and talk + + align:start position:0% +have a guest speaker come in and talk + + + align:start position:0% +have a guest speaker come in and talk +about a cost model that he's developed + + align:start position:0% +about a cost model that he's developed + + + align:start position:0% +about a cost model that he's developed +for PV uh into very high level of + + align:start position:0% +for PV uh into very high level of + + + align:start position:0% +for PV uh into very high level of +detail. So it'll be a lot of fun. Uh and + + align:start position:0% +detail. So it'll be a lot of fun. Uh and + + + align:start position:0% +detail. So it'll be a lot of fun. Uh and +you'll be able to use that cost model to + + align:start position:0% +you'll be able to use that cost model to + + + align:start position:0% +you'll be able to use that cost model to +model your own uh PV uh devices, + + align:start position:0% +model your own uh PV uh devices, + + + align:start position:0% +model your own uh PV uh devices, +apparatus, and so forth. Um next + + align:start position:0% +apparatus, and so forth. Um next + + + align:start position:0% +apparatus, and so forth. Um next +Tuesday, a week from today, we'll be + + align:start position:0% +Tuesday, a week from today, we'll be + + + align:start position:0% +Tuesday, a week from today, we'll be +touring a PV facility. It'll be here on + + align:start position:0% +touring a PV facility. It'll be here on + + + align:start position:0% +touring a PV facility. It'll be here on +campus to make it easy for everybody. + + align:start position:0% +campus to make it easy for everybody. + + + align:start position:0% +campus to make it easy for everybody. +We'll go over to the student center and + + align:start position:0% +We'll go over to the student center and + + + align:start position:0% +We'll go over to the student center and +tour the PB system up on the roof there + + align:start position:0% +tour the PB system up on the roof there + + + align:start position:0% +tour the PB system up on the roof there +as well as the balance of system + + align:start position:0% +as well as the balance of system + + + align:start position:0% +as well as the balance of system +components. So, be able to have a a + + align:start position:0% +components. So, be able to have a a + + + align:start position:0% +components. So, be able to have a a +close-up uh look at at how that works. + + align:start position:0% +close-up uh look at at how that works. + + + align:start position:0% +close-up uh look at at how that works. +Um, but today cost, price, markets, and + + align:start position:0% +Um, but today cost, price, markets, and + + + align:start position:0% +Um, but today cost, price, markets, and +subsidies. We want to talk about those + + align:start position:0% +subsidies. We want to talk about those + + + align:start position:0% +subsidies. We want to talk about those +uh items because at the end of the day, + + align:start position:0% +uh items because at the end of the day, + + + align:start position:0% +uh items because at the end of the day, +PV is a product that is competing + + align:start position:0% +PV is a product that is competing + + + align:start position:0% +PV is a product that is competing +against bulk electricity, right? And if + + align:start position:0% +against bulk electricity, right? And if + + + align:start position:0% +against bulk electricity, right? And if +we can't compete against the bulk + + align:start position:0% +we can't compete against the bulk + + + align:start position:0% +we can't compete against the bulk +electricity, then uh we're our on-grid + + align:start position:0% +electricity, then uh we're our on-grid + + + align:start position:0% +electricity, then uh we're our on-grid +applications are going to be rather + + align:start position:0% +applications are going to be rather + + + align:start position:0% +applications are going to be rather +limited. uh so we want to understand uh + + align:start position:0% +limited. uh so we want to understand uh + + + align:start position:0% +limited. uh so we want to understand uh +how all this works and fits together. Uh + + align:start position:0% +how all this works and fits together. Uh + + + align:start position:0% +how all this works and fits together. Uh +so I'll be providing you several + + align:start position:0% +so I'll be providing you several + + + align:start position:0% +so I'll be providing you several +snapshots and several pieces of the + + align:start position:0% +snapshots and several pieces of the + + + align:start position:0% +snapshots and several pieces of the +puzzle uh with a lot of discussion back + + align:start position:0% +puzzle uh with a lot of discussion back + + + align:start position:0% +puzzle uh with a lot of discussion back +and forth over the course of today's + + align:start position:0% +and forth over the course of today's + + + align:start position:0% +and forth over the course of today's +lecture. So uh first off let's dive into + + align:start position:0% +lecture. So uh first off let's dive into + + + align:start position:0% +lecture. So uh first off let's dive into +PV cost and price. Um what is the + + align:start position:0% +PV cost and price. Um what is the + + + align:start position:0% +PV cost and price. Um what is the +difference between cost and + + align:start position:0% +difference between cost and + + + align:start position:0% +difference between cost and +price? They're used interchangeably in + + align:start position:0% +price? They're used interchangeably in + + + align:start position:0% +price? They're used interchangeably in +in colloquial language but there's a big + + align:start position:0% +in colloquial language but there's a big + + + align:start position:0% +in colloquial language but there's a big +difference. Jessica, cost might be what + + align:start position:0% +difference. Jessica, cost might be what + + + align:start position:0% +difference. Jessica, cost might be what +it cost to manufacture and price is what + + align:start position:0% +it cost to manufacture and price is what + + + align:start position:0% +it cost to manufacture and price is what +it's sold at for the Absolutely. So cost + + align:start position:0% +it's sold at for the Absolutely. So cost + + + align:start position:0% +it's sold at for the Absolutely. So cost +is what it actually costs to make to + + align:start position:0% +is what it actually costs to make to + + + align:start position:0% +is what it actually costs to make to +manufacture and price is what people are + + align:start position:0% +manufacture and price is what people are + + + align:start position:0% +manufacture and price is what people are +willing to pay for it, what the market + + align:start position:0% +willing to pay for it, what the market + + + align:start position:0% +willing to pay for it, what the market +is uh demanding, right? So sometimes + + align:start position:0% +is uh demanding, right? So sometimes + + + align:start position:0% +is uh demanding, right? So sometimes +price can be above cost. That's you're + + align:start position:0% +price can be above cost. That's you're + + + align:start position:0% +price can be above cost. That's you're +hopefully in that situation most of the + + align:start position:0% +hopefully in that situation most of the + + + align:start position:0% +hopefully in that situation most of the +time. And sometimes price can actually + + align:start position:0% +time. And sometimes price can actually + + + align:start position:0% +time. And sometimes price can actually +be below cost. What is an example of + + align:start position:0% +be below cost. What is an example of + + + align:start position:0% +be below cost. What is an example of +when price could be below cost? + + align:start position:0% +when price could be below cost? + + + align:start position:0% +when price could be below cost? +The Amazon Kindle. the Amazon Kindle. + + align:start position:0% +The Amazon Kindle. the Amazon Kindle. + + + align:start position:0% +The Amazon Kindle. the Amazon Kindle. +Why would why would it be doing that? Uh + + align:start position:0% +Why would why would it be doing that? Uh + + + align:start position:0% +Why would why would it be doing that? Uh +because they want to get people to adopt + + align:start position:0% +because they want to get people to adopt + + + align:start position:0% +because they want to get people to adopt +the device and then make money on + + align:start position:0% +the device and then make money on + + + align:start position:0% +the device and then make money on +subscriptions to books or + + align:start position:0% +subscriptions to books or + + + align:start position:0% +subscriptions to books or +a loss leader, right? Something like uh + + align:start position:0% +a loss leader, right? Something like uh + + + align:start position:0% +a loss leader, right? Something like uh +for example, if you buy your razor uh + + align:start position:0% +for example, if you buy your razor uh + + + align:start position:0% +for example, if you buy your razor uh +handle and that's really cheap, but then + + align:start position:0% +handle and that's really cheap, but then + + + align:start position:0% +handle and that's really cheap, but then +they they gouge you on blades. or uh uh + + align:start position:0% +they they gouge you on blades. or uh uh + + + align:start position:0% +they they gouge you on blades. or uh uh +other examples if they include the the + + align:start position:0% +other examples if they include the the + + + align:start position:0% +other examples if they include the the +cheap items in the front of a store. You + + align:start position:0% +cheap items in the front of a store. You + + + align:start position:0% +cheap items in the front of a store. You +walk inside the store and then you're + + align:start position:0% +walk inside the store and then you're + + + align:start position:0% +walk inside the store and then you're +you're bared by all the more expensive + + align:start position:0% +you're bared by all the more expensive + + + align:start position:0% +you're bared by all the more expensive +ones right inside. So loss leading can + + align:start position:0% +ones right inside. So loss leading can + + + align:start position:0% +ones right inside. So loss leading can +be one example of price below cost and + + align:start position:0% +be one example of price below cost and + + + align:start position:0% +be one example of price below cost and +other other + + align:start position:0% + + + + align:start position:0% + +examples. What if I start making a gizmo + + align:start position:0% +examples. What if I start making a gizmo + + + align:start position:0% +examples. What if I start making a gizmo +and I pocket an enormous profit and all + + align:start position:0% +and I pocket an enormous profit and all + + + align:start position:0% +and I pocket an enormous profit and all +of you start watching me make that gizmo + + align:start position:0% +of you start watching me make that gizmo + + + align:start position:0% +of you start watching me make that gizmo +and say, "Hey, I I can do that. It's + + align:start position:0% +and say, "Hey, I I can do that. It's + + + align:start position:0% +and say, "Hey, I I can do that. It's +pretty simple. It's not it doesn't take + + align:start position:0% +pretty simple. It's not it doesn't take + + + align:start position:0% +pretty simple. It's not it doesn't take +a rocket scientist to to manufacture + + align:start position:0% +a rocket scientist to to manufacture + + + align:start position:0% +a rocket scientist to to manufacture +that gizmo. I can do it too. And + + align:start position:0% +that gizmo. I can do it too. And + + + align:start position:0% +that gizmo. I can do it too. And +everybody starts manufacturing gizmos. + + align:start position:0% +everybody starts manufacturing gizmos. + + + align:start position:0% +everybody starts manufacturing gizmos. +Um pretty soon we overwhelm the demand + + align:start position:0% +Um pretty soon we overwhelm the demand + + + align:start position:0% +Um pretty soon we overwhelm the demand +at least at that given price point and + + align:start position:0% +at least at that given price point and + + + align:start position:0% +at least at that given price point and +the price is depressed as we enter a + + align:start position:0% +the price is depressed as we enter a + + + align:start position:0% +the price is depressed as we enter a +price war, right? We enter what is + + align:start position:0% +price war, right? We enter what is + + + align:start position:0% +price war, right? We enter what is +called an over supply condition. That's + + align:start position:0% +called an over supply condition. That's + + + align:start position:0% +called an over supply condition. That's +another example where price can fall + + align:start position:0% +another example where price can fall + + + align:start position:0% +another example where price can fall +below cost. And another reason why price + + align:start position:0% +below cost. And another reason why price + + + align:start position:0% +below cost. And another reason why price +can fall below cost is simply uh the + + align:start position:0% +can fall below cost is simply uh the + + + align:start position:0% +can fall below cost is simply uh the +price or the market you're trying to + + align:start position:0% +price or the market you're trying to + + + align:start position:0% +price or the market you're trying to +address simply won't buy your product at + + align:start position:0% +address simply won't buy your product at + + + align:start position:0% +address simply won't buy your product at +that cost. And that's the case with + + align:start position:0% +that cost. And that's the case with + + + align:start position:0% +that cost. And that's the case with +substitution economics. If we're + + align:start position:0% +substitution economics. If we're + + + align:start position:0% +substitution economics. If we're +competing against fossil fuel-based + + align:start position:0% +competing against fossil fuel-based + + + align:start position:0% +competing against fossil fuel-based +electricity, let's say, and we want to + + align:start position:0% +electricity, let's say, and we want to + + + align:start position:0% +electricity, let's say, and we want to +compete against that, we might uh we + + align:start position:0% +compete against that, we might uh we + + + align:start position:0% +compete against that, we might uh we +might not be able to manufacture solar + + align:start position:0% +might not be able to manufacture solar + + + align:start position:0% +might not be able to manufacture solar +panels cheap enough to address certain + + align:start position:0% +panels cheap enough to address certain + + + align:start position:0% +panels cheap enough to address certain +markets. For example, Wyoming, which has + + align:start position:0% +markets. For example, Wyoming, which has + + + align:start position:0% +markets. For example, Wyoming, which has +5 cents per kilowatt hour electricity uh + + align:start position:0% +5 cents per kilowatt hour electricity uh + + + align:start position:0% +5 cents per kilowatt hour electricity uh +due to cheap cheap uh fossil fuel. Um + + align:start position:0% +due to cheap cheap uh fossil fuel. Um + + + align:start position:0% +due to cheap cheap uh fossil fuel. Um +the southeast of the United States as + + align:start position:0% +the southeast of the United States as + + + align:start position:0% +the southeast of the United States as +well, where the TVA, the Tennessee + + align:start position:0% +well, where the TVA, the Tennessee + + + align:start position:0% +well, where the TVA, the Tennessee +Valley Authority, has very low priced + + align:start position:0% +Valley Authority, has very low priced + + + align:start position:0% +Valley Authority, has very low priced +nuclear and coal power. Uh so these are + + align:start position:0% +nuclear and coal power. Uh so these are + + + align:start position:0% +nuclear and coal power. Uh so these are +examples of where price might be be + + align:start position:0% +examples of where price might be be + + + align:start position:0% +examples of where price might be be +below cost. We're going to get more into + + align:start position:0% +below cost. We're going to get more into + + + align:start position:0% +below cost. We're going to get more into +that over the course of today's lecture. + + align:start position:0% +that over the course of today's lecture. + + + align:start position:0% +that over the course of today's lecture. +Uh because there are some very + + align:start position:0% +Uh because there are some very + + + align:start position:0% +Uh because there are some very +interesting geopolitical uh debates + + align:start position:0% +interesting geopolitical uh debates + + + align:start position:0% +interesting geopolitical uh debates +occurring right now. Uh oftentimes the + + align:start position:0% +occurring right now. Uh oftentimes the + + + align:start position:0% +occurring right now. Uh oftentimes the +two sides are very staunch in their + + align:start position:0% +two sides are very staunch in their + + + align:start position:0% +two sides are very staunch in their +positions and there isn't much nuance. + + align:start position:0% +positions and there isn't much nuance. + + + align:start position:0% +positions and there isn't much nuance. +There isn't much shade of gray. There is + + align:start position:0% +There isn't much shade of gray. There is + + + align:start position:0% +There isn't much shade of gray. There is +there aren't many rational arguments + + align:start position:0% +there aren't many rational arguments + + + align:start position:0% +there aren't many rational arguments +presented and instead we're going to be + + align:start position:0% +presented and instead we're going to be + + + align:start position:0% +presented and instead we're going to be +diving into some of that uh discussing + + align:start position:0% +diving into some of that uh discussing + + + align:start position:0% +diving into some of that uh discussing +the nuance over today's lecture. Let's + + align:start position:0% +the nuance over today's lecture. Let's + + + align:start position:0% +the nuance over today's lecture. Let's +dive into cost. Uh first off, this is a + + align:start position:0% +dive into cost. Uh first off, this is a + + + align:start position:0% +dive into cost. Uh first off, this is a +paper that I've presented already in in + + align:start position:0% +paper that I've presented already in in + + + align:start position:0% +paper that I've presented already in in +class. I've also steered some of the + + align:start position:0% +class. I've also steered some of the + + + align:start position:0% +class. I've also steered some of the +project groups toward it. Um this is uh + + align:start position:0% +project groups toward it. Um this is uh + + + align:start position:0% +project groups toward it. Um this is uh +a proceeding back in Whoa, this wasn't + + align:start position:0% +a proceeding back in Whoa, this wasn't + + + align:start position:0% +a proceeding back in Whoa, this wasn't +2009. My apologies. This is 2003. Um + + align:start position:0% +2009. My apologies. This is 2003. Um + + + align:start position:0% +2009. My apologies. This is 2003. Um +this was the uh presented at the third + + align:start position:0% +this was the uh presented at the third + + + align:start position:0% +this was the uh presented at the third +world conference of uh photovoltaic + + align:start position:0% +world conference of uh photovoltaic + + + align:start position:0% +world conference of uh photovoltaic +energy conversion by Tom Surk. Uh + + align:start position:0% +energy conversion by Tom Surk. Uh + + + align:start position:0% +energy conversion by Tom Surk. Uh +presenting a very simple uh uh cost + + align:start position:0% +presenting a very simple uh uh cost + + + align:start position:0% +presenting a very simple uh uh cost +model, if you will, for PV. Uh more + + align:start position:0% +model, if you will, for PV. Uh more + + + align:start position:0% +model, if you will, for PV. Uh more +specifically, the impact of efficiency + + align:start position:0% +specifically, the impact of efficiency + + + align:start position:0% +specifically, the impact of efficiency +on cost. And by no means was this the + + align:start position:0% +on cost. And by no means was this the + + + align:start position:0% +on cost. And by no means was this the +first time that something like this had + + align:start position:0% +first time that something like this had + + + align:start position:0% +first time that something like this had +ever been presented, but it was a nice + + align:start position:0% +ever been presented, but it was a nice + + + align:start position:0% +ever been presented, but it was a nice +uh summary of of the work to date. Um + + align:start position:0% +uh summary of of the work to date. Um + + + align:start position:0% +uh summary of of the work to date. Um +highlighting several uh would say key + + align:start position:0% +highlighting several uh would say key + + + align:start position:0% +highlighting several uh would say key +lever cost levers. Um efficiency, that's + + align:start position:0% +lever cost levers. Um efficiency, that's + + + align:start position:0% +lever cost levers. Um efficiency, that's +the solar conversion efficiency. + + align:start position:0% +the solar conversion efficiency. + + + align:start position:0% +the solar conversion efficiency. +Processing costs, that's the materials + + align:start position:0% +Processing costs, that's the materials + + + align:start position:0% +Processing costs, that's the materials +and and processing costs for the uh u + + align:start position:0% +and and processing costs for the uh u + + + align:start position:0% +and and processing costs for the uh u +for the module in dollars per meter + + align:start position:0% +for the module in dollars per meter + + + align:start position:0% +for the module in dollars per meter +squared. the manufacturing yield. That + + align:start position:0% +squared. the manufacturing yield. That + + + align:start position:0% +squared. the manufacturing yield. That +means uh out of say a hundred cells that + + align:start position:0% +means uh out of say a hundred cells that + + + align:start position:0% +means uh out of say a hundred cells that +enter your manufacturing line, how many + + align:start position:0% +enter your manufacturing line, how many + + + align:start position:0% +enter your manufacturing line, how many +make it through to the other side + + align:start position:0% +make it through to the other side + + + align:start position:0% +make it through to the other side +without breaking? Um and and and or + + align:start position:0% +without breaking? Um and and and or + + + align:start position:0% +without breaking? Um and and and or +being discarded uh due to due to + + align:start position:0% +being discarded uh due to due to + + + align:start position:0% +being discarded uh due to due to +manufacturing defects. Uh capital + + align:start position:0% +manufacturing defects. Uh capital + + + align:start position:0% +manufacturing defects. Uh capital +equipment cost uh that's depreciated + + align:start position:0% +equipment cost uh that's depreciated + + + align:start position:0% +equipment cost uh that's depreciated +over several years, meaning you buy + + align:start position:0% +over several years, meaning you buy + + + align:start position:0% +over several years, meaning you buy +equipment up front, but then uh due to + + align:start position:0% +equipment up front, but then uh due to + + + align:start position:0% +equipment up front, but then uh due to +financial gimmicks, you're allowed to um + + align:start position:0% +financial gimmicks, you're allowed to um + + + align:start position:0% +financial gimmicks, you're allowed to um +uh allow that cost to hit your books + + align:start position:0% +uh allow that cost to hit your books + + + align:start position:0% +uh allow that cost to hit your books +over an extended period of time, not all + + align:start position:0% +over an extended period of time, not all + + + align:start position:0% +over an extended period of time, not all +at once up front. Um overhead and so + + align:start position:0% +at once up front. Um overhead and so + + + align:start position:0% +at once up front. Um overhead and so +forth. overhead being the uh health + + align:start position:0% +forth. overhead being the uh health + + + align:start position:0% +forth. overhead being the uh health +insurance if it is paid to the workers. + + align:start position:0% +insurance if it is paid to the workers. + + + align:start position:0% +insurance if it is paid to the workers. +Um and and uh of course uh R&D and and + + align:start position:0% +Um and and uh of course uh R&D and and + + + align:start position:0% +Um and and uh of course uh R&D and and +um the CEO salary and so forth could be + + align:start position:0% +um the CEO salary and so forth could be + + + align:start position:0% +um the CEO salary and so forth could be +lumped in the uh so this is a very + + align:start position:0% +lumped in the uh so this is a very + + + align:start position:0% +lumped in the uh so this is a very +simple way of of of estimating cost. + + align:start position:0% +simple way of of of estimating cost. + + + align:start position:0% +simple way of of of estimating cost. +It's it's u a linear equation a direct + + align:start position:0% +It's it's u a linear equation a direct + + + align:start position:0% +It's it's u a linear equation a direct +uh uh relationship. What is I would say + + align:start position:0% +uh uh relationship. What is I would say + + + align:start position:0% +uh uh relationship. What is I would say +the economics uh a more sophisticated + + align:start position:0% +the economics uh a more sophisticated + + + align:start position:0% +the economics uh a more sophisticated +way of looking at cost uh other than + + align:start position:0% +way of looking at cost uh other than + + + align:start position:0% +way of looking at cost uh other than +just saying it's the dollars per watt + + align:start position:0% +just saying it's the dollars per watt + + + align:start position:0% +just saying it's the dollars per watt +peak um you would look at it in terms of + + align:start position:0% +peak um you would look at it in terms of + + + align:start position:0% +peak um you would look at it in terms of +cents per kilowatt hour right you would + + align:start position:0% +cents per kilowatt hour right you would + + + align:start position:0% +cents per kilowatt hour right you would +look at it in terms of how much do you + + align:start position:0% +look at it in terms of how much do you + + + align:start position:0% +look at it in terms of how much do you +pay for your electricity coming out of + + align:start position:0% +pay for your electricity coming out of + + + align:start position:0% +pay for your electricity coming out of +the wall or in this case out of the + + align:start position:0% +the wall or in this case out of the + + + align:start position:0% +the wall or in this case out of the +panels what would factor in to what is + + align:start position:0% +panels what would factor in to what is + + + align:start position:0% +panels what would factor in to what is +called the levelized cost of electricity + + align:start position:0% +called the levelized cost of electricity + + + align:start position:0% +called the levelized cost of electricity +when you're actually calculating cents + + align:start position:0% +when you're actually calculating cents + + + align:start position:0% +when you're actually calculating cents +per kilowatt hour how would you convert + + align:start position:0% +per kilowatt hour how would you convert + + + align:start position:0% +per kilowatt hour how would you convert +dollars per watt peak. Okay, I know how + + align:start position:0% +dollars per watt peak. Okay, I know how + + + align:start position:0% +dollars per watt peak. Okay, I know how +many dollars it took to manufacture + + align:start position:0% +many dollars it took to manufacture + + + align:start position:0% +many dollars it took to manufacture +this. I can also uh what would say + + align:start position:0% +this. I can also uh what would say + + + align:start position:0% +this. I can also uh what would say +depreciate my equipment costs over + + align:start position:0% +depreciate my equipment costs over + + + align:start position:0% +depreciate my equipment costs over +several years to manufacture this. Um, + + align:start position:0% +several years to manufacture this. Um, + + + align:start position:0% +several years to manufacture this. Um, +how would I go from dollars per watt + + align:start position:0% +how would I go from dollars per watt + + + align:start position:0% +how would I go from dollars per watt +peak into cents per kilowatt hour? We + + align:start position:0% +peak into cents per kilowatt hour? We + + + align:start position:0% +peak into cents per kilowatt hour? We +all agree that cents per kilowatt hour + + align:start position:0% +all agree that cents per kilowatt hour + + + align:start position:0% +all agree that cents per kilowatt hour +is the metric of importance, right? + + align:start position:0% +is the metric of importance, right? + + + align:start position:0% +is the metric of importance, right? +That's what we pay on our electricity + + align:start position:0% +That's what we pay on our electricity + + + align:start position:0% +That's what we pay on our electricity +bills, or at least some of us do. Um, so + + align:start position:0% +bills, or at least some of us do. Um, so + + + align:start position:0% +bills, or at least some of us do. Um, so +when we pay our electricity bills, we're + + align:start position:0% +when we pay our electricity bills, we're + + + align:start position:0% +when we pay our electricity bills, we're +paying in cents per kilowatt hour from + + align:start position:0% +paying in cents per kilowatt hour from + + + align:start position:0% +paying in cents per kilowatt hour from +the grid. And when we manufacture our + + align:start position:0% +the grid. And when we manufacture our + + + align:start position:0% +the grid. And when we manufacture our +solar panels, we pay in dollars per watt + + align:start position:0% +solar panels, we pay in dollars per watt + + + align:start position:0% +solar panels, we pay in dollars per watt +peak. Let's start simple. Why is dollars + + align:start position:0% +peak. Let's start simple. Why is dollars + + + align:start position:0% +peak. Let's start simple. Why is dollars +per watt peak at all + + align:start position:0% +per watt peak at all + + + align:start position:0% +per watt peak at all +useful? It's so far removed from cents + + align:start position:0% +useful? It's so far removed from cents + + + align:start position:0% +useful? It's so far removed from cents +per kilowatt hour that it it almost + + align:start position:0% +per kilowatt hour that it it almost + + + align:start position:0% +per kilowatt hour that it it almost +seems like an artificial metric. Why why + + align:start position:0% +seems like an artificial metric. Why why + + + align:start position:0% +seems like an artificial metric. Why why +again do we use dollars per watt peak? + + align:start position:0% +again do we use dollars per watt peak? + + + align:start position:0% +again do we use dollars per watt peak? +Jesse, because most um coal based or + + align:start position:0% +Jesse, because most um coal based or + + + align:start position:0% +Jesse, because most um coal based or +most fossil fuel based electricity is + + align:start position:0% +most fossil fuel based electricity is + + + align:start position:0% +most fossil fuel based electricity is +based on a capacity factor which is just + + align:start position:0% +based on a capacity factor which is just + + + align:start position:0% +based on a capacity factor which is just +kilowatt um bas which is measured in + + align:start position:0% +kilowatt um bas which is measured in + + + align:start position:0% +kilowatt um bas which is measured in +kilowatt. That's that's a good way of + + align:start position:0% +kilowatt. That's that's a good way of + + + align:start position:0% +kilowatt. That's that's a good way of +looking at it. Um and then the capacity + + align:start position:0% +looking at it. Um and then the capacity + + + align:start position:0% +looking at it. Um and then the capacity +factor of solar would be based on what? + + align:start position:0% +factor of solar would be based on what? + + + align:start position:0% +factor of solar would be based on what? +on it capacity on on the solar resource + + align:start position:0% +on it capacity on on the solar resource + + + align:start position:0% +on it capacity on on the solar resource +locally, right? Um and and that might + + align:start position:0% +locally, right? Um and and that might + + + align:start position:0% +locally, right? Um and and that might +vary from location to location. Yeah. + + align:start position:0% +vary from location to location. Yeah. + + + align:start position:0% +vary from location to location. Yeah. +Okay. So, what dollars per watt peak + + align:start position:0% +Okay. So, what dollars per watt peak + + + align:start position:0% +Okay. So, what dollars per watt peak +allows you to do is given a rated name + + align:start position:0% +allows you to do is given a rated name + + + align:start position:0% +allows you to do is given a rated name +plate capacity, you can calculate based + + align:start position:0% +plate capacity, you can calculate based + + + align:start position:0% +plate capacity, you can calculate based +on the solar resource locally, how much + + align:start position:0% +on the solar resource locally, how much + + + align:start position:0% +on the solar resource locally, how much +energy will be produced over a certain + + align:start position:0% +energy will be produced over a certain + + + align:start position:0% +energy will be produced over a certain +period of time, right? And then from + + align:start position:0% +period of time, right? And then from + + + align:start position:0% +period of time, right? And then from +that, you can calculate your cents per + + align:start position:0% +that, you can calculate your cents per + + + align:start position:0% +that, you can calculate your cents per +kilowatt hour, right? because now we're + + align:start position:0% +kilowatt hour, right? because now we're + + + align:start position:0% +kilowatt hour, right? because now we're +converting from power uh or rated name + + align:start position:0% +converting from power uh or rated name + + + align:start position:0% +converting from power uh or rated name +plate power into energy which we can use + + align:start position:0% +plate power into energy which we can use + + + align:start position:0% +plate power into energy which we can use +and uh which has economic value. So + + align:start position:0% +and uh which has economic value. So + + + align:start position:0% +and uh which has economic value. So +there there there is a rationale then + + align:start position:0% +there there there is a rationale then + + + align:start position:0% +there there there is a rationale then +for uh giving uh name plate capacity in + + align:start position:0% +for uh giving uh name plate capacity in + + + align:start position:0% +for uh giving uh name plate capacity in +terms of watt peak in other words rating + + align:start position:0% +terms of watt peak in other words rating + + + align:start position:0% +terms of watt peak in other words rating +a factory in terms of megawws per year + + align:start position:0% +a factory in terms of megawws per year + + + align:start position:0% +a factory in terms of megawws per year +or gigawatts per year produced. Uh that + + align:start position:0% +or gigawatts per year produced. Uh that + + + align:start position:0% +or gigawatts per year produced. Uh that +means that each module that goes under + + align:start position:0% +means that each module that goes under + + + align:start position:0% +means that each module that goes under +the cell tester is rated and there's an + + align:start position:0% +the cell tester is rated and there's an + + + align:start position:0% +the cell tester is rated and there's an +estimate uh based on the cumulative + + align:start position:0% +estimate uh based on the cumulative + + + align:start position:0% +estimate uh based on the cumulative +module production what the total watt + + align:start position:0% +module production what the total watt + + + align:start position:0% +module production what the total watt +peak output of that factory was. And + + align:start position:0% +peak output of that factory was. And + + + align:start position:0% +peak output of that factory was. And +then depending on where those modules go + + align:start position:0% +then depending on where those modules go + + + align:start position:0% +then depending on where those modules go +in the world they might produce + + align:start position:0% +in the world they might produce + + + align:start position:0% +in the world they might produce +different amounts of energy. Uh if you + + align:start position:0% +different amounts of energy. Uh if you + + + align:start position:0% +different amounts of energy. Uh if you +take those same modules install them in + + align:start position:0% +take those same modules install them in + + + align:start position:0% +take those same modules install them in +Alaska or Arizona you're going to get + + align:start position:0% +Alaska or Arizona you're going to get + + + align:start position:0% +Alaska or Arizona you're going to get +widely varying energy outputs. Okay. So + + align:start position:0% +widely varying energy outputs. Okay. So + + + align:start position:0% +widely varying energy outputs. Okay. So +then how do we transition? We we we have + + align:start position:0% +then how do we transition? We we we have + + + align:start position:0% +then how do we transition? We we we have +the dollars per watt peak. We have to + + align:start position:0% +the dollars per watt peak. We have to + + + align:start position:0% +the dollars per watt peak. We have to +know the local solar insulation that + + align:start position:0% +know the local solar insulation that + + + align:start position:0% +know the local solar insulation that +would allow us to calculate what the + + align:start position:0% +would allow us to calculate what the + + + align:start position:0% +would allow us to calculate what the +cents per kilowatt hour would be + + align:start position:0% +cents per kilowatt hour would be + + + align:start position:0% +cents per kilowatt hour would be +assuming a certain cost of capital. We + + align:start position:0% +assuming a certain cost of capital. We + + + align:start position:0% +assuming a certain cost of capital. We +have to buy those panels up front, + + align:start position:0% +have to buy those panels up front, + + + align:start position:0% +have to buy those panels up front, +right? You have to buy from me a huge + + align:start position:0% +right? You have to buy from me a huge + + + align:start position:0% +right? You have to buy from me a huge +number of panels which are going to last + + align:start position:0% +number of panels which are going to last + + + align:start position:0% +number of panels which are going to last +for 20 25 years. I'll guarantee it. But + + align:start position:0% +for 20 25 years. I'll guarantee it. But + + + align:start position:0% +for 20 25 years. I'll guarantee it. But +you have to front that money up front. + + align:start position:0% +you have to front that money up front. + + + align:start position:0% +you have to front that money up front. +Which means that you need to loan or + + align:start position:0% +Which means that you need to loan or + + + align:start position:0% +Which means that you need to loan or +lend that money from a bank from a bank + + align:start position:0% +lend that money from a bank from a bank + + + align:start position:0% +lend that money from a bank from a bank +or from a financial institution. Uh and + + align:start position:0% +or from a financial institution. Uh and + + + align:start position:0% +or from a financial institution. Uh and +then you'll be paying a certain amount + + align:start position:0% +then you'll be paying a certain amount + + + align:start position:0% +then you'll be paying a certain amount +of interest every year. And it's the + + align:start position:0% +of interest every year. And it's the + + + align:start position:0% +of interest every year. And it's the +spread. It's the difference between the + + align:start position:0% +spread. It's the difference between the + + + align:start position:0% +spread. It's the difference between the +interest payments and the money saved + + align:start position:0% +interest payments and the money saved + + + align:start position:0% +interest payments and the money saved +that's going to turn your profit. And + + align:start position:0% +that's going to turn your profit. And + + + align:start position:0% +that's going to turn your profit. And +that's what's called the rate of return + + align:start position:0% +that's what's called the rate of return + + + align:start position:0% +that's what's called the rate of return +of your investment. Uh and there's also + + align:start position:0% +of your investment. Uh and there's also + + + align:start position:0% +of your investment. Uh and there's also +a payback period or a monetary payback + + align:start position:0% +a payback period or a monetary payback + + + align:start position:0% +a payback period or a monetary payback +period over which uh you're not going to + + align:start position:0% +period over which uh you're not going to + + + align:start position:0% +period over which uh you're not going to +be making money on on average, but uh + + align:start position:0% +be making money on on average, but uh + + + align:start position:0% +be making money on on average, but uh +after the payback period is finished, + + align:start position:0% +after the payback period is finished, + + + align:start position:0% +after the payback period is finished, +then your solar uh array will be a money + + align:start position:0% +then your solar uh array will be a money + + + align:start position:0% +then your solar uh array will be a money +press. It'll be printing money. And so + + align:start position:0% +press. It'll be printing money. And so + + + align:start position:0% +press. It'll be printing money. And so +over the entire lifetime of the + + align:start position:0% +over the entire lifetime of the + + + align:start position:0% +over the entire lifetime of the +investment, you can calculate an average + + align:start position:0% +investment, you can calculate an average + + + align:start position:0% +investment, you can calculate an average +rate of return. Okay? So um given that + + align:start position:0% +rate of return. Okay? So um given that + + + align:start position:0% +rate of return. Okay? So um given that +uh setup um we're going to be talking + + align:start position:0% +uh setup um we're going to be talking + + + align:start position:0% +uh setup um we're going to be talking +about some incentive mechanisms and um + + align:start position:0% +about some incentive mechanisms and um + + + align:start position:0% +about some incentive mechanisms and um +uh and and today really really simple + + align:start position:0% +uh and and today really really simple + + + align:start position:0% +uh and and today really really simple +cost model uh more on Thursday uh when + + align:start position:0% +cost model uh more on Thursday uh when + + + align:start position:0% +cost model uh more on Thursday uh when +we get back to uh back back to this how + + align:start position:0% +we get back to uh back back to this how + + + align:start position:0% +we get back to uh back back to this how +we calculate uh cost um in a more + + align:start position:0% +we calculate uh cost um in a more + + + align:start position:0% +we calculate uh cost um in a more +sophisticated manner. I I want to + + align:start position:0% +sophisticated manner. I I want to + + + align:start position:0% +sophisticated manner. I I want to +introduce this concept very simply at + + align:start position:0% +introduce this concept very simply at + + + align:start position:0% +introduce this concept very simply at +first just because there are some + + align:start position:0% +first just because there are some + + + align:start position:0% +first just because there are some +parameters here in the sensitivity + + align:start position:0% +parameters here in the sensitivity + + + align:start position:0% +parameters here in the sensitivity +analysis that overwhelm all the others + + align:start position:0% +analysis that overwhelm all the others + + + align:start position:0% +analysis that overwhelm all the others +and they can be very simply seen in an + + align:start position:0% +and they can be very simply seen in an + + + align:start position:0% +and they can be very simply seen in an +equation like that right up there and + + align:start position:0% +equation like that right up there and + + + align:start position:0% +equation like that right up there and +one of them is efficiency. The + + align:start position:0% +one of them is efficiency. The + + + align:start position:0% +one of them is efficiency. The +processing costs also matter quite a + + align:start position:0% +processing costs also matter quite a + + + align:start position:0% +processing costs also matter quite a +bit. Okay. Um inside of processing costs + + align:start position:0% +bit. Okay. Um inside of processing costs + + + align:start position:0% +bit. Okay. Um inside of processing costs +um you also have labor and commodity + + align:start position:0% +um you also have labor and commodity + + + align:start position:0% +um you also have labor and commodity +materials right and those can vary + + align:start position:0% +materials right and those can vary + + + align:start position:0% +materials right and those can vary +significantly from region to region. + + align:start position:0% +significantly from region to region. + + + align:start position:0% +significantly from region to region. +So um there there are a number of uh uh + + align:start position:0% +So um there there are a number of uh uh + + + align:start position:0% +So um there there are a number of uh uh +assessments out there. I'm I'm going to + + align:start position:0% +assessments out there. I'm I'm going to + + + align:start position:0% +assessments out there. I'm I'm going to +be uh leading us into the the current + + align:start position:0% +be uh leading us into the the current + + + align:start position:0% +be uh leading us into the the current +big debate which has exploded in + + align:start position:0% +big debate which has exploded in + + + align:start position:0% +big debate which has exploded in +Washington DC. Uh the case of Celindra + + align:start position:0% +Washington DC. Uh the case of Celindra + + + align:start position:0% +Washington DC. Uh the case of Celindra +and then Solar World filing uh the um uh + + align:start position:0% +and then Solar World filing uh the um uh + + + align:start position:0% +and then Solar World filing uh the um uh +would say the the um complaint with the + + align:start position:0% +would say the the um complaint with the + + + align:start position:0% +would say the the um complaint with the +US commerce uh department. Um, I'll be + + align:start position:0% +US commerce uh department. Um, I'll be + + + align:start position:0% +US commerce uh department. Um, I'll be +I'll be easing us into this whole + + align:start position:0% +I'll be easing us into this whole + + + align:start position:0% +I'll be easing us into this whole +question of US and and and uh and and + + align:start position:0% +question of US and and and uh and and + + + align:start position:0% +question of US and and and uh and and +foreign manufacturing, using that more + + align:start position:0% +foreign manufacturing, using that more + + + align:start position:0% +foreign manufacturing, using that more +as a hook to get us interested in the + + align:start position:0% +as a hook to get us interested in the + + + align:start position:0% +as a hook to get us interested in the +overall topics of the day. Um, and then + + align:start position:0% +overall topics of the day. Um, and then + + + align:start position:0% +overall topics of the day. Um, and then +toward the end, hopefully you'll be able + + align:start position:0% +toward the end, hopefully you'll be able + + + align:start position:0% +toward the end, hopefully you'll be able +to see with more shades of gray uh what + + align:start position:0% +to see with more shades of gray uh what + + + align:start position:0% +to see with more shades of gray uh what +exactly is going on and perhaps + + align:start position:0% +exactly is going on and perhaps + + + align:start position:0% +exactly is going on and perhaps +formulate opinions of your own. So, + + align:start position:0% +formulate opinions of your own. So, + + + align:start position:0% +formulate opinions of your own. So, +where where is PV cost actually at? + + align:start position:0% +where where is PV cost actually at? + + + align:start position:0% +where where is PV cost actually at? +Where where do the current cost numbers + + align:start position:0% +Where where do the current cost numbers + + + align:start position:0% +Where where do the current cost numbers +currently stand? Um, it is extremely + + align:start position:0% +currently stand? Um, it is extremely + + + align:start position:0% +currently stand? Um, it is extremely +difficult to get at true cost. Price, + + align:start position:0% +difficult to get at true cost. Price, + + + align:start position:0% +difficult to get at true cost. Price, +price is easy, right? You go out there, + + align:start position:0% +price is easy, right? You go out there, + + + align:start position:0% +price is easy, right? You go out there, +probe the market, see what people are + + align:start position:0% +probe the market, see what people are + + + align:start position:0% +probe the market, see what people are +willing to sell panels at, maybe send a + + align:start position:0% +willing to sell panels at, maybe send a + + + align:start position:0% +willing to sell panels at, maybe send a +few emails to a few companies saying, + + align:start position:0% +few emails to a few companies saying, + + + align:start position:0% +few emails to a few companies saying, +"Hey, I want to installund hundred of + + align:start position:0% +"Hey, I want to installund hundred of + + + align:start position:0% +"Hey, I want to installund hundred of +your panels, how much you're willing to + + align:start position:0% +your panels, how much you're willing to + + + align:start position:0% +your panels, how much you're willing to +sell them to me." Um, this is what + + align:start position:0% +sell them to me." Um, this is what + + + align:start position:0% +sell them to me." Um, this is what +people do. They probe the market, they + + align:start position:0% +people do. They probe the market, they + + + align:start position:0% +people do. They probe the market, they +test it. So price is fairly easy to + + align:start position:0% +test it. So price is fairly easy to + + + align:start position:0% +test it. So price is fairly easy to +gauge, but manufacturing cost. If I go + + align:start position:0% +gauge, but manufacturing cost. If I go + + + align:start position:0% +gauge, but manufacturing cost. If I go +up to you and say, "Hey, can you tell me + + align:start position:0% +up to you and say, "Hey, can you tell me + + + align:start position:0% +up to you and say, "Hey, can you tell me +how much it costs to manufacture panels + + align:start position:0% +how much it costs to manufacture panels + + + align:start position:0% +how much it costs to manufacture panels +in your factory? Would you be willing to + + align:start position:0% +in your factory? Would you be willing to + + + align:start position:0% +in your factory? Would you be willing to +give me that information?" They'd + + align:start position:0% +give me that information?" They'd + + + align:start position:0% +give me that information?" They'd +probably say, "No." um probably seeing + + align:start position:0% +probably say, "No." um probably seeing + + + align:start position:0% +probably say, "No." um probably seeing +no definitely to me as a professor. + + align:start position:0% +no definitely to me as a professor. + + + align:start position:0% +no definitely to me as a professor. +Maybe you as students they might they + + align:start position:0% +Maybe you as students they might they + + + align:start position:0% +Maybe you as students they might they +might show you a little bit more of how + + align:start position:0% +might show you a little bit more of how + + + align:start position:0% +might show you a little bit more of how +it actually works under the hood since + + align:start position:0% +it actually works under the hood since + + + align:start position:0% +it actually works under the hood since +many people believe in the educational + + align:start position:0% +many people believe in the educational + + + align:start position:0% +many people believe in the educational +mission. But by and large people are + + align:start position:0% +mission. But by and large people are + + + align:start position:0% +mission. But by and large people are +fairly secretive about this because they + + align:start position:0% +fairly secretive about this because they + + + align:start position:0% +fairly secretive about this because they +realize that their stock price is + + align:start position:0% +realize that their stock price is + + + align:start position:0% +realize that their stock price is +heavily dependent on market perception. + + align:start position:0% +heavily dependent on market perception. + + + align:start position:0% +heavily dependent on market perception. +And if I go out there and write an + + align:start position:0% +And if I go out there and write an + + + align:start position:0% +And if I go out there and write an +article and say, "Hey, uh your company + + align:start position:0% +article and say, "Hey, uh your company + + + align:start position:0% +article and say, "Hey, uh your company +uh produces panels at twice the cost of + + align:start position:0% +uh produces panels at twice the cost of + + + align:start position:0% +uh produces panels at twice the cost of +yours, uh investors are going to flee + + align:start position:0% +yours, uh investors are going to flee + + + align:start position:0% +yours, uh investors are going to flee +your company, especially if it comes out + + align:start position:0% +your company, especially if it comes out + + + align:start position:0% +your company, especially if it comes out +of a university like MIT." And so + + align:start position:0% +of a university like MIT." And so + + + align:start position:0% +of a university like MIT." And so +there's a there are big repercussions + + align:start position:0% +there's a there are big repercussions + + + align:start position:0% +there's a there are big repercussions +associated with divulgation of of cost + + align:start position:0% +associated with divulgation of of cost + + + align:start position:0% +associated with divulgation of of cost +numbers and that's why it's very hard to + + align:start position:0% +numbers and that's why it's very hard to + + + align:start position:0% +numbers and that's why it's very hard to +get to the bottom of it. What you find + + align:start position:0% +get to the bottom of it. What you find + + + align:start position:0% +get to the bottom of it. What you find +most often are aggregators. These are + + align:start position:0% +most often are aggregators. These are + + + align:start position:0% +most often are aggregators. These are +consultancies that work with several + + align:start position:0% +consultancies that work with several + + + align:start position:0% +consultancies that work with several +companies. Um they may be for example um + + align:start position:0% +companies. Um they may be for example um + + + align:start position:0% +companies. Um they may be for example um +Photon Consulting across the river uh in + + align:start position:0% +Photon Consulting across the river uh in + + + align:start position:0% +Photon Consulting across the river uh in +in Boston. It might be Green Techch + + align:start position:0% +in Boston. It might be Green Techch + + + align:start position:0% +in Boston. It might be Green Techch +Media uh consulting branch which is + + align:start position:0% +Media uh consulting branch which is + + + align:start position:0% +Media uh consulting branch which is +located here in Cambridge, + + align:start position:0% +located here in Cambridge, + + + align:start position:0% +located here in Cambridge, +Massachusetts. Um there are many + + align:start position:0% +Massachusetts. Um there are many + + + align:start position:0% +Massachusetts. Um there are many +consulting companies and several of them + + align:start position:0% +consulting companies and several of them + + + align:start position:0% +consulting companies and several of them +based here in uh the Boston area. uh and + + align:start position:0% +based here in uh the Boston area. uh and + + + align:start position:0% +based here in uh the Boston area. uh and +these consultant companies work with + + align:start position:0% +these consultant companies work with + + + align:start position:0% +these consultant companies work with +several PV manufacturers and over time + + align:start position:0% +several PV manufacturers and over time + + + align:start position:0% +several PV manufacturers and over time +begin aggregating data and presenting + + align:start position:0% +begin aggregating data and presenting + + + align:start position:0% +begin aggregating data and presenting +market trends, generalized market + + align:start position:0% +market trends, generalized market + + + align:start position:0% +market trends, generalized market +trends, right? Few of them single out + + align:start position:0% +trends, right? Few of them single out + + + align:start position:0% +trends, right? Few of them single out +specific companies, but most of them + + align:start position:0% +specific companies, but most of them + + + align:start position:0% +specific companies, but most of them +just aggregate the data and present + + align:start position:0% +just aggregate the data and present + + + align:start position:0% +just aggregate the data and present +general trends. Uh I've presented to you + + align:start position:0% +general trends. Uh I've presented to you + + + align:start position:0% +general trends. Uh I've presented to you +this uh a few articles as of late. Um + + align:start position:0% +this uh a few articles as of late. Um + + + align:start position:0% +this uh a few articles as of late. Um +these are relatively recent um within + + align:start position:0% +these are relatively recent um within + + + align:start position:0% +these are relatively recent um within +the last three to four years. And + + align:start position:0% +the last three to four years. And + + + align:start position:0% +the last three to four years. And +because there has been so much change + + align:start position:0% +because there has been so much change + + + align:start position:0% +because there has been so much change +over the last 3 to four years within the + + align:start position:0% +over the last 3 to four years within the + + + align:start position:0% +over the last 3 to four years within the +PV market, even an article three years + + align:start position:0% +PV market, even an article three years + + + align:start position:0% +PV market, even an article three years +ago is highly outdated, right? So you'll + + align:start position:0% +ago is highly outdated, right? So you'll + + + align:start position:0% +ago is highly outdated, right? So you'll +want information that's within the last + + align:start position:0% +want information that's within the last + + + align:start position:0% +want information that's within the last +year if you're going to be using uh cost + + align:start position:0% +year if you're going to be using uh cost + + + align:start position:0% +year if you're going to be using uh cost +and price information for your projects, + + align:start position:0% +and price information for your projects, + + + align:start position:0% +and price information for your projects, +even within the last few + + align:start position:0% +even within the last few + + + align:start position:0% +even within the last few +months. And if any of you have any + + align:start position:0% +months. And if any of you have any + + + align:start position:0% +months. And if any of you have any +doubts in that regard, you can come talk + + align:start position:0% +doubts in that regard, you can come talk + + + align:start position:0% +doubts in that regard, you can come talk +to me. So the fully loaded uh module + + align:start position:0% +to me. So the fully loaded uh module + + + align:start position:0% +to me. So the fully loaded uh module +manufacturing cost uh is is shown here. + + align:start position:0% +manufacturing cost uh is is shown here. + + + align:start position:0% +manufacturing cost uh is is shown here. +uh an estimate again an aggregation + + align:start position:0% +uh an estimate again an aggregation + + + align:start position:0% +uh an estimate again an aggregation +based on um access to multiple companies + + align:start position:0% +based on um access to multiple companies + + + align:start position:0% +based on um access to multiple companies +data polyilicon this of course being + + align:start position:0% +data polyilicon this of course being + + + align:start position:0% +data polyilicon this of course being +crystal and silicon technology which + + align:start position:0% +crystal and silicon technology which + + + align:start position:0% +crystal and silicon technology which +accounts for about 90 85% of the current + + align:start position:0% +accounts for about 90 85% of the current + + + align:start position:0% +accounts for about 90 85% of the current +market poly silicon in blue depreciation + + align:start position:0% +market poly silicon in blue depreciation + + + align:start position:0% +market poly silicon in blue depreciation +in red what's depreciation + + align:start position:0% + + + + align:start position:0% + +is that + + align:start position:0% +is that + + + align:start position:0% +is that +the discounting of the capital that we + + align:start position:0% +the discounting of the capital that we + + + align:start position:0% +the discounting of the capital that we +we just talked about exactly exactly so + + align:start position:0% +we just talked about exactly exactly so + + + align:start position:0% +we just talked about exactly exactly so +what that means is I + + align:start position:0% +what that means is I + + + align:start position:0% +what that means is I +I borrow a lot of money to manufacture + + align:start position:0% +I borrow a lot of money to manufacture + + + align:start position:0% +I borrow a lot of money to manufacture +these panels uh to to buy the equipment + + align:start position:0% +these panels uh to to buy the equipment + + + align:start position:0% +these panels uh to to buy the equipment +to buy the factory and set everything + + align:start position:0% +to buy the factory and set everything + + + align:start position:0% +to buy the factory and set everything +up. Um and then I have to pay interest + + align:start position:0% +up. Um and then I have to pay interest + + + align:start position:0% +up. Um and then I have to pay interest +on my loans, right? So and and and I + + align:start position:0% +on my loans, right? So and and and I + + + align:start position:0% +on my loans, right? So and and and I +have to pay interest on uh the loans and + + align:start position:0% +have to pay interest on uh the loans and + + + align:start position:0% +have to pay interest on uh the loans and +I I what I do is I I start writing off + + align:start position:0% +I I what I do is I I start writing off + + + align:start position:0% +I I what I do is I I start writing off +the equipment as a loss uh to the + + align:start position:0% +the equipment as a loss uh to the + + + align:start position:0% +the equipment as a loss uh to the +company. So uh that equipment is going + + align:start position:0% +company. So uh that equipment is going + + + align:start position:0% +company. So uh that equipment is going +to be useful over a certain period of + + align:start position:0% +to be useful over a certain period of + + + align:start position:0% +to be useful over a certain period of +time and then we can assume that it's + + align:start position:0% +time and then we can assume that it's + + + align:start position:0% +time and then we can assume that it's +outdated and that I'll need to buy the + + align:start position:0% +outdated and that I'll need to buy the + + + align:start position:0% +outdated and that I'll need to buy the +next generation of manufacturing + + align:start position:0% +next generation of manufacturing + + + align:start position:0% +next generation of manufacturing +equipment. uh so I can begin writing off + + align:start position:0% +equipment. uh so I can begin writing off + + + align:start position:0% +equipment. uh so I can begin writing off +the value of that equipment over a + + align:start position:0% +the value of that equipment over a + + + align:start position:0% +the value of that equipment over a +certain schedule over a certain period + + align:start position:0% +certain schedule over a certain period + + + align:start position:0% +certain schedule over a certain period +of years five seven depending on the + + align:start position:0% +of years five seven depending on the + + + align:start position:0% +of years five seven depending on the +company depending on the way they're um + + align:start position:0% +company depending on the way they're um + + + align:start position:0% +company depending on the way they're um +I don't want to say cooking their books + + align:start position:0% +I don't want to say cooking their books + + + align:start position:0% +I don't want to say cooking their books +but the way they're uh manipulating the + + align:start position:0% +but the way they're uh manipulating the + + + align:start position:0% +but the way they're uh manipulating the +numbers in the accounting sector so um + + align:start position:0% +numbers in the accounting sector so um + + + align:start position:0% +numbers in the accounting sector so um +the depreciation varies um and it varies + + align:start position:0% +the depreciation varies um and it varies + + + align:start position:0% +the depreciation varies um and it varies +because the interest rate at which you + + align:start position:0% +because the interest rate at which you + + + align:start position:0% +because the interest rate at which you +acquire the + + align:start position:0% +acquire the + + + align:start position:0% +acquire the +loan and the interest rate or the the + + align:start position:0% +loan and the interest rate or the the + + + align:start position:0% +loan and the interest rate or the the +the inflation rate of the uh of the + + align:start position:0% +the inflation rate of the uh of the + + + align:start position:0% +the inflation rate of the uh of the +particular ular currency in question is + + align:start position:0% +particular ular currency in question is + + + align:start position:0% +particular ular currency in question is +different in different regions, right? + + align:start position:0% +different in different regions, right? + + + align:start position:0% +different in different regions, right? +So when you're calculating depreciation, + + align:start position:0% +So when you're calculating depreciation, + + + align:start position:0% +So when you're calculating depreciation, +both of those things matter and that's + + align:start position:0% +both of those things matter and that's + + + align:start position:0% +both of those things matter and that's +why those numbers can vary from place to + + align:start position:0% +why those numbers can vary from place to + + + align:start position:0% +why those numbers can vary from place to +place. Uh materials, materials cost + + align:start position:0% +place. Uh materials, materials cost + + + align:start position:0% +place. Uh materials, materials cost +these are the materials used to + + align:start position:0% +these are the materials used to + + + align:start position:0% +these are the materials used to +manufacture the module, typically called + + align:start position:0% +manufacture the module, typically called + + + align:start position:0% +manufacture the module, typically called +commodity materials. You would look at + + align:start position:0% +commodity materials. You would look at + + + align:start position:0% +commodity materials. You would look at +them as the extruded aluminum + + align:start position:0% +them as the extruded aluminum + + + align:start position:0% +them as the extruded aluminum +components, the glass in the front side, + + align:start position:0% +components, the glass in the front side, + + + align:start position:0% +components, the glass in the front side, +um the encapsulate materials and so + + align:start position:0% +um the encapsulate materials and so + + + align:start position:0% +um the encapsulate materials and so +forth. All the fancy stuff that we saw + + align:start position:0% +forth. All the fancy stuff that we saw + + + align:start position:0% +forth. All the fancy stuff that we saw +when we visited Foundhoffer last + + align:start position:0% +when we visited Foundhoffer last + + + align:start position:0% +when we visited Foundhoffer last +week. Um let's see what else we have. + + align:start position:0% +week. Um let's see what else we have. + + + align:start position:0% +week. Um let's see what else we have. +Labor. Okay, that's pretty + + align:start position:0% +Labor. Okay, that's pretty + + + align:start position:0% +Labor. Okay, that's pretty +straightforward to see. Um, if we're + + align:start position:0% +straightforward to see. Um, if we're + + + align:start position:0% +straightforward to see. Um, if we're +manufacturing in China, we were looking + + align:start position:0% +manufacturing in China, we were looking + + + align:start position:0% +manufacturing in China, we were looking +at a labor rate uh could be could be as + + align:start position:0% +at a labor rate uh could be could be as + + + align:start position:0% +at a labor rate uh could be could be as +low base labor without adding um housing + + align:start position:0% +low base labor without adding um housing + + + align:start position:0% +low base labor without adding um housing +and so forth. The base labor rate could + + align:start position:0% +and so forth. The base labor rate could + + + align:start position:0% +and so forth. The base labor rate could +be as low as $275 an hour in US dollars. + + align:start position:0% +be as low as $275 an hour in US dollars. + + + align:start position:0% +be as low as $275 an hour in US dollars. +Um, and uh in US dollars in the United + + align:start position:0% +Um, and uh in US dollars in the United + + + align:start position:0% +Um, and uh in US dollars in the United +States, we could be looking at labor + + align:start position:0% +States, we could be looking at labor + + + align:start position:0% +States, we could be looking at labor +rates of somewhere in the range of $16 + + align:start position:0% +rates of somewhere in the range of $16 + + + align:start position:0% +rates of somewhere in the range of $16 +an hour, right? Um before you start + + align:start position:0% +an hour, right? Um before you start + + + align:start position:0% +an hour, right? Um before you start +adding in uh social security and + + align:start position:0% +adding in uh social security and + + + align:start position:0% +adding in uh social security and +benefits and so forth. And um there + + align:start position:0% +benefits and so forth. And um there + + + align:start position:0% +benefits and so forth. And um there +might there may be different levels of + + align:start position:0% +might there may be different levels of + + + align:start position:0% +might there may be different levels of +automation in the two different places + + align:start position:0% +automation in the two different places + + + align:start position:0% +automation in the two different places +which shifts costs from labor into uh + + align:start position:0% +which shifts costs from labor into uh + + + align:start position:0% +which shifts costs from labor into uh +capital equipment, right? So if you + + align:start position:0% +capital equipment, right? So if you + + + align:start position:0% +capital equipment, right? So if you +realize that you have a much higher + + align:start position:0% +realize that you have a much higher + + + align:start position:0% +realize that you have a much higher +labor cost, uh you might want to buy + + align:start position:0% +labor cost, uh you might want to buy + + + align:start position:0% +labor cost, uh you might want to buy +more robots to do the manufacturing. Uh + + align:start position:0% +more robots to do the manufacturing. Uh + + + align:start position:0% +more robots to do the manufacturing. Uh +and vice versa, if you're in China and + + align:start position:0% +and vice versa, if you're in China and + + + align:start position:0% +and vice versa, if you're in China and +you realize, oh my goodness, our labor + + align:start position:0% +you realize, oh my goodness, our labor + + + align:start position:0% +you realize, oh my goodness, our labor +rates are increasing uh almost + + align:start position:0% +rates are increasing uh almost + + + align:start position:0% +rates are increasing uh almost +exponentially, definitely super linearly + + align:start position:0% +exponentially, definitely super linearly + + + align:start position:0% +exponentially, definitely super linearly +with time as as as the country takes off + + align:start position:0% +with time as as as the country takes off + + + align:start position:0% +with time as as as the country takes off +and and there's inflation uh labor wage + + align:start position:0% +and and there's inflation uh labor wage + + + align:start position:0% +and and there's inflation uh labor wage +inflation. Um, a company that is trying + + align:start position:0% +inflation. Um, a company that is trying + + + align:start position:0% +inflation. Um, a company that is trying +to project forward five or seven years + + align:start position:0% +to project forward five or seven years + + + align:start position:0% +to project forward five or seven years +might say, "Well, goodness, it doesn't + + align:start position:0% +might say, "Well, goodness, it doesn't + + + align:start position:0% +might say, "Well, goodness, it doesn't +make sense for me to flood my + + align:start position:0% +make sense for me to flood my + + + align:start position:0% +make sense for me to flood my +manufacturing line with people right now + + align:start position:0% +manufacturing line with people right now + + + align:start position:0% +manufacturing line with people right now +because that manufacturing line still + + align:start position:0% +because that manufacturing line still + + + align:start position:0% +because that manufacturing line still +has to make a profit in five years. And + + align:start position:0% +has to make a profit in five years. And + + + align:start position:0% +has to make a profit in five years. And +so, I'm going to buy more robots now. + + align:start position:0% +so, I'm going to buy more robots now. + + + align:start position:0% +so, I'm going to buy more robots now. +Even though I might not need it today, I + + align:start position:0% +Even though I might not need it today, I + + + align:start position:0% +Even though I might not need it today, I +might need it in five years." And so, + + align:start position:0% +might need it in five years." And so, + + + align:start position:0% +might need it in five years." And so, +there's a bit of risk calculation that + + align:start position:0% +there's a bit of risk calculation that + + + align:start position:0% +there's a bit of risk calculation that +gets thrown into this as well, right? + + align:start position:0% +gets thrown into this as well, right? + + + align:start position:0% +gets thrown into this as well, right? +Um, utilities and overhead. Okay, that's + + align:start position:0% +Um, utilities and overhead. Okay, that's + + + align:start position:0% +Um, utilities and overhead. Okay, that's +pretty straightforward. If we're looking + + align:start position:0% +pretty straightforward. If we're looking + + + align:start position:0% +pretty straightforward. If we're looking +at utilities, that means electricity + + align:start position:0% +at utilities, that means electricity + + + align:start position:0% +at utilities, that means electricity +mostly to run uh the lines. uh it could + + align:start position:0% +mostly to run uh the lines. uh it could + + + align:start position:0% +mostly to run uh the lines. uh it could +also be uh water which is is used in the + + align:start position:0% +also be uh water which is is used in the + + + align:start position:0% +also be uh water which is is used in the +manufacturing process. Okay. Um note the + + align:start position:0% +manufacturing process. Okay. Um note the + + + align:start position:0% +manufacturing process. Okay. Um note the +caveats in several of these studies + + align:start position:0% +caveats in several of these studies + + + align:start position:0% +caveats in several of these studies +especially the the one out of Lawrence + + align:start position:0% +especially the the one out of Lawrence + + + align:start position:0% +especially the the one out of Lawrence +Berkeley National Laboratory um + + align:start position:0% +Berkeley National Laboratory um + + + align:start position:0% +Berkeley National Laboratory um +manufacturing cost you can you can do a + + align:start position:0% +manufacturing cost you can you can do a + + + align:start position:0% +manufacturing cost you can you can do a +number of things with that. You can + + align:start position:0% +number of things with that. You can + + + align:start position:0% +number of things with that. You can +assume that you're buying your + + align:start position:0% +assume that you're buying your + + + align:start position:0% +assume that you're buying your +polysilicon. You're buying the + + align:start position:0% +polysilicon. You're buying the + + + align:start position:0% +polysilicon. You're buying the +polysilicon manufacturing cells modules + + align:start position:0% +polysilicon manufacturing cells modules + + + align:start position:0% +polysilicon manufacturing cells modules +and and systems. Or you can assume that + + align:start position:0% +and and systems. Or you can assume that + + + align:start position:0% +and and systems. Or you can assume that +you're buying the cells and the cells + + align:start position:0% +you're buying the cells and the cells + + + align:start position:0% +you're buying the cells and the cells +are commodity products equal in in price + + align:start position:0% +are commodity products equal in in price + + + align:start position:0% +are commodity products equal in in price +throughout the world and that you're + + align:start position:0% +throughout the world and that you're + + + align:start position:0% +throughout the world and that you're +just manufacturing the modules. Right? + + align:start position:0% +just manufacturing the modules. Right? + + + align:start position:0% +just manufacturing the modules. Right? +So you can cut cost in many different + + align:start position:0% +So you can cut cost in many different + + + align:start position:0% +So you can cut cost in many different +ways depending on what assumptions you + + align:start position:0% +ways depending on what assumptions you + + + align:start position:0% +ways depending on what assumptions you +make. The price of the cell on the + + align:start position:0% +make. The price of the cell on the + + + align:start position:0% +make. The price of the cell on the +international market may be very + + align:start position:0% +international market may be very + + + align:start position:0% +international market may be very +different than the cost to manufacture + + align:start position:0% +different than the cost to manufacture + + + align:start position:0% +different than the cost to manufacture +that cell in your particular country. + + align:start position:0% +that cell in your particular country. + + + align:start position:0% +that cell in your particular country. +And and cost is almost one of those + + align:start position:0% +And and cost is almost one of those + + + align:start position:0% +And and cost is almost one of those +things that you can torture until it + + align:start position:0% +things that you can torture until it + + + align:start position:0% +things that you can torture until it +tells you the story you want it to tell, + + align:start position:0% +tells you the story you want it to tell, + + + align:start position:0% +tells you the story you want it to tell, +right? It's it's one of those things + + align:start position:0% +right? It's it's one of those things + + + align:start position:0% +right? It's it's one of those things +where if if you did these numbers a + + align:start position:0% +where if if you did these numbers a + + + align:start position:0% +where if if you did these numbers a +little bit differently and said, "Okay, + + align:start position:0% +little bit differently and said, "Okay, + + + align:start position:0% +little bit differently and said, "Okay, +we're buying cells um and and just + + align:start position:0% +we're buying cells um and and just + + + align:start position:0% +we're buying cells um and and just +making modules and then adding shipment + + align:start position:0% +making modules and then adding shipment + + + align:start position:0% +making modules and then adding shipment +fees, let's say transport fees from + + align:start position:0% +fees, let's say transport fees from + + + align:start position:0% +fees, let's say transport fees from +China to the United States, China and US + + align:start position:0% +China to the United States, China and US + + + align:start position:0% +China to the United States, China and US +might look almost equal." + + align:start position:0% +might look almost equal." + + + align:start position:0% +might look almost equal." +Whereas if you integrate over the entire + + align:start position:0% +Whereas if you integrate over the entire + + + align:start position:0% +Whereas if you integrate over the entire +supply chain and say okay I'm going to + + align:start position:0% +supply chain and say okay I'm going to + + + align:start position:0% +supply chain and say okay I'm going to +be manufacturing my polysilicon then my + + align:start position:0% +be manufacturing my polysilicon then my + + + align:start position:0% +be manufacturing my polysilicon then my +wafers then my cells and finally the + + align:start position:0% +wafers then my cells and finally the + + + align:start position:0% +wafers then my cells and finally the +modules um then you might start seeing + + align:start position:0% +modules um then you might start seeing + + + align:start position:0% +modules um then you might start seeing +some disparity based on these other + + align:start position:0% +some disparity based on these other + + + align:start position:0% +some disparity based on these other +parameters shown here. Point being um be + + align:start position:0% +parameters shown here. Point being um be + + + align:start position:0% +parameters shown here. Point being um be +careful when you see a cost assessment + + align:start position:0% +careful when you see a cost assessment + + + align:start position:0% +careful when you see a cost assessment +probe their base assumptions and try to + + align:start position:0% +probe their base assumptions and try to + + + align:start position:0% +probe their base assumptions and try to +understand what their biases and + + align:start position:0% +understand what their biases and + + + align:start position:0% +understand what their biases and +motivations were for presenting uh that + + align:start position:0% +motivations were for presenting uh that + + + align:start position:0% +motivations were for presenting uh that +particular comparison. um especially + + align:start position:0% +particular comparison. um especially + + + align:start position:0% +particular comparison. um especially +nowadays where you have more and more + + align:start position:0% +nowadays where you have more and more + + + align:start position:0% +nowadays where you have more and more +parties with vested interests in + + align:start position:0% +parties with vested interests in + + + align:start position:0% +parties with vested interests in +presenting one story or + + align:start position:0% +presenting one story or + + + align:start position:0% +presenting one story or +another. We'll get to that in a few + + align:start position:0% +another. We'll get to that in a few + + + align:start position:0% +another. We'll get to that in a few +slides. All right, experience learning + + align:start position:0% +slides. All right, experience learning + + + align:start position:0% +slides. All right, experience learning +curve. Okay, then we're getting into + + align:start position:0% +curve. Okay, then we're getting into + + + align:start position:0% +curve. Okay, then we're getting into +price. Uh we're venturing beyond cost + + align:start position:0% +price. Uh we're venturing beyond cost + + + align:start position:0% +price. Uh we're venturing beyond cost +and into the regime of price which is + + align:start position:0% +and into the regime of price which is + + + align:start position:0% +and into the regime of price which is +definitely more easily measurable and + + align:start position:0% +definitely more easily measurable and + + + align:start position:0% +definitely more easily measurable and +that's why we have some fairly good data + + align:start position:0% +that's why we have some fairly good data + + + align:start position:0% +that's why we have some fairly good data +going back um several decades. And uh + + align:start position:0% +going back um several decades. And uh + + + align:start position:0% +going back um several decades. And uh +you can see here uh this is cumulative + + align:start position:0% +you can see here uh this is cumulative + + + align:start position:0% +you can see here uh this is cumulative +sales in gigawatt peak. That means the + + align:start position:0% +sales in gigawatt peak. That means the + + + align:start position:0% +sales in gigawatt peak. That means the +cumulative number of widgets in this + + align:start position:0% +cumulative number of widgets in this + + + align:start position:0% +cumulative number of widgets in this +case watt peaks produced uh by solar + + align:start position:0% +case watt peaks produced uh by solar + + + align:start position:0% +case watt peaks produced uh by solar +industries worldwide. And this is the + + align:start position:0% +industries worldwide. And this is the + + + align:start position:0% +industries worldwide. And this is the +global average um module selling price + + align:start position:0% +global average um module selling price + + + align:start position:0% +global average um module selling price +not the system the module right so not + + align:start position:0% +not the system the module right so not + + + align:start position:0% +not the system the module right so not +the balance of system installation labor + + align:start position:0% +the balance of system installation labor + + + align:start position:0% +the balance of system installation labor +and so forth but just the manufacturing + + align:start position:0% +and so forth but just the manufacturing + + + align:start position:0% +and so forth but just the manufacturing +of the module. And what we can see here + + align:start position:0% +of the module. And what we can see here + + + align:start position:0% +of the module. And what we can see here +is a general trend over time with a + + align:start position:0% +is a general trend over time with a + + + align:start position:0% +is a general trend over time with a +decreasing price. That's good. Sorry. + + align:start position:0% +decreasing price. That's good. Sorry. + + + align:start position:0% +decreasing price. That's good. Sorry. +Decreasing price with time. That's + + align:start position:0% +Decreasing price with time. That's + + + align:start position:0% +Decreasing price with time. That's +that's excellent. Um what is that + + align:start position:0% +that's excellent. Um what is that + + + align:start position:0% +that's excellent. Um what is that +called? This this uh this curve here + + align:start position:0% +called? This this uh this curve here + + + align:start position:0% +called? This this uh this curve here +plotted in a log log scale where you + + align:start position:0% +plotted in a log log scale where you + + + align:start position:0% +plotted in a log log scale where you +have a line + + align:start position:0% +have a line + + + align:start position:0% +have a line +uh through the cumulative manufacturing + + align:start position:0% +uh through the cumulative manufacturing + + + align:start position:0% +uh through the cumulative manufacturing +production versus versus versus price. + + align:start position:0% +production versus versus versus price. + + + align:start position:0% +production versus versus versus price. +What what is that curve called? + + align:start position:0% +What what is that curve called? + + + align:start position:0% +What what is that curve called? +Experience learning. It's an experience + + align:start position:0% +Experience learning. It's an experience + + + align:start position:0% +Experience learning. It's an experience +learning curve. And you'll get something + + align:start position:0% +learning curve. And you'll get something + + + align:start position:0% +learning curve. And you'll get something +similar for any high-tech product. + + align:start position:0% +similar for any high-tech product. + + + align:start position:0% +similar for any high-tech product. +Computers, toasters, as long as the + + align:start position:0% +Computers, toasters, as long as the + + + align:start position:0% +Computers, toasters, as long as the +product isn't changing significantly + + align:start position:0% +product isn't changing significantly + + + align:start position:0% +product isn't changing significantly +with time. And even sometimes if they + + align:start position:0% +with time. And even sometimes if they + + + align:start position:0% +with time. And even sometimes if they +are uh as it's the case with a solar + + align:start position:0% +are uh as it's the case with a solar + + + align:start position:0% +are uh as it's the case with a solar +panel, solar panels back in the 1960s or + + align:start position:0% +panel, solar panels back in the 1960s or + + + align:start position:0% +panel, solar panels back in the 1960s or +1970s rather look very different than + + align:start position:0% +1970s rather look very different than + + + align:start position:0% +1970s rather look very different than +the solar panels today in terms of the + + align:start position:0% +the solar panels today in terms of the + + + align:start position:0% +the solar panels today in terms of the +materials and the processes used. And + + align:start position:0% +materials and the processes used. And + + + align:start position:0% +materials and the processes used. And +yet it all falls along this very + + align:start position:0% +yet it all falls along this very + + + align:start position:0% +yet it all falls along this very +interesting experience learning curve. + + align:start position:0% +interesting experience learning curve. + + + align:start position:0% +interesting experience learning curve. +So it's extremely tempting to say oh + + align:start position:0% +So it's extremely tempting to say oh + + + align:start position:0% +So it's extremely tempting to say oh +well what what price do we need to reach + + align:start position:0% +well what what price do we need to reach + + + align:start position:0% +well what what price do we need to reach +to be cost competitive or or competitive + + align:start position:0% +to be cost competitive or or competitive + + + align:start position:0% +to be cost competitive or or competitive +let's say with bulk electricity? We need + + align:start position:0% +let's say with bulk electricity? We need + + + align:start position:0% +let's say with bulk electricity? We need +to reach a price of say 50 cents per + + align:start position:0% +to reach a price of say 50 cents per + + + align:start position:0% +to reach a price of say 50 cents per +watt peak. Oh easy. We'll just project + + align:start position:0% +watt peak. Oh easy. We'll just project + + + align:start position:0% +watt peak. Oh easy. We'll just project +forward and we'll see how much + + align:start position:0% +forward and we'll see how much + + + align:start position:0% +forward and we'll see how much +cumulative production is needed. um and + + align:start position:0% +cumulative production is needed. um and + + + align:start position:0% +cumulative production is needed. um and +then we'll subsidize until we get to + + align:start position:0% +then we'll subsidize until we get to + + + align:start position:0% +then we'll subsidize until we get to +that cumulative production and and + + align:start position:0% +that cumulative production and and + + + align:start position:0% +that cumulative production and and +bingo, voila, it'll happen by magic. + + align:start position:0% +bingo, voila, it'll happen by magic. + + + align:start position:0% +bingo, voila, it'll happen by magic. +Well, the reality is that each little + + align:start position:0% +Well, the reality is that each little + + + align:start position:0% +Well, the reality is that each little +bump here along the learning curve was + + align:start position:0% +bump here along the learning curve was + + + align:start position:0% +bump here along the learning curve was +was some if you look closely, you can + + align:start position:0% +was some if you look closely, you can + + + align:start position:0% +was some if you look closely, you can +kind of see these little bumps here. + + align:start position:0% +kind of see these little bumps here. + + + align:start position:0% +kind of see these little bumps here. +There were many traumatic events within + + align:start position:0% +There were many traumatic events within + + + align:start position:0% +There were many traumatic events within +the industry that forced people to uh + + align:start position:0% +the industry that forced people to uh + + + align:start position:0% +the industry that forced people to uh +innovate uh to produce better + + align:start position:0% +innovate uh to produce better + + + align:start position:0% +innovate uh to produce better +technology. um whether it's the + + align:start position:0% +technology. um whether it's the + + + align:start position:0% +technology. um whether it's the +technology itself, something designed + + align:start position:0% +technology itself, something designed + + + align:start position:0% +technology itself, something designed +here in the laboratory at MIT or + + align:start position:0% +here in the laboratory at MIT or + + + align:start position:0% +here in the laboratory at MIT or +Harvard, or whether it's something u uh + + align:start position:0% +Harvard, or whether it's something u uh + + + align:start position:0% +Harvard, or whether it's something u uh +innovated on the manufacturing line + + align:start position:0% +innovated on the manufacturing line + + + align:start position:0% +innovated on the manufacturing line +where they realized, oh, this is a more + + align:start position:0% +where they realized, oh, this is a more + + + align:start position:0% +where they realized, oh, this is a more +efficient way of manufacturing the solar + + align:start position:0% +efficient way of manufacturing the solar + + + align:start position:0% +efficient way of manufacturing the solar +panels. It's cheaper. Um this little + + align:start position:0% +panels. It's cheaper. Um this little + + + align:start position:0% +panels. It's cheaper. Um this little +bump right here, boom. This represents a + + align:start position:0% +bump right here, boom. This represents a + + + align:start position:0% +bump right here, boom. This represents a +period in which prices actually went + + align:start position:0% +period in which prices actually went + + + align:start position:0% +period in which prices actually went +back up year in and year out. What could + + align:start position:0% +back up year in and year out. What could + + + align:start position:0% +back up year in and year out. What could +cause prices to go + + align:start position:0% +cause prices to go + + + align:start position:0% +cause prices to go +up? What are what are some of the + + align:start position:0% +up? What are what are some of the + + + align:start position:0% +up? What are what are some of the +motivations for that? I mean, scale is + + align:start position:0% +motivations for that? I mean, scale is + + + align:start position:0% +motivations for that? I mean, scale is +increasing. The market's growing. It's + + align:start position:0% +increasing. The market's growing. It's + + + align:start position:0% +increasing. The market's growing. It's +not shrinking at all. It's not like the + + align:start position:0% +not shrinking at all. It's not like the + + + align:start position:0% +not shrinking at all. It's not like the +points went back here as they went up. + + align:start position:0% +points went back here as they went up. + + + align:start position:0% +points went back here as they went up. +Um, so the market continued to grow. The + + align:start position:0% +Um, so the market continued to grow. The + + + align:start position:0% +Um, so the market continued to grow. The +manufacturing capacity continued to + + align:start position:0% +manufacturing capacity continued to + + + align:start position:0% +manufacturing capacity continued to +grow, but the price went back up. What + + align:start position:0% +grow, but the price went back up. What + + + align:start position:0% +grow, but the price went back up. What +what could have caused that? + + align:start position:0% +what could have caused that? + + + align:start position:0% +what could have caused that? +Supply. Demand outpaces supply. Exactly. + + align:start position:0% +Supply. Demand outpaces supply. Exactly. + + + align:start position:0% +Supply. Demand outpaces supply. Exactly. +So, uh, in this specific case, what + + align:start position:0% +So, uh, in this specific case, what + + + align:start position:0% +So, uh, in this specific case, what +happened was the polysilicon feed stock, + + align:start position:0% +happened was the polysilicon feed stock, + + + align:start position:0% +happened was the polysilicon feed stock, +which is the input material into this + + align:start position:0% +which is the input material into this + + + align:start position:0% +which is the input material into this +entire process, was in short supply. uh + + align:start position:0% +entire process, was in short supply. uh + + + align:start position:0% +entire process, was in short supply. uh +takes about well in those days it took + + align:start position:0% +takes about well in those days it took + + + align:start position:0% +takes about well in those days it took +about 24 to 36 months to get a new plant + + align:start position:0% +about 24 to 36 months to get a new plant + + + align:start position:0% +about 24 to 36 months to get a new plant +online long lead time billions of + + align:start position:0% +online long lead time billions of + + + align:start position:0% +online long lead time billions of +dollars of investment and so the + + align:start position:0% +dollars of investment and so the + + + align:start position:0% +dollars of investment and so the +polysilicon suppliers didn't really want + + align:start position:0% +polysilicon suppliers didn't really want + + + align:start position:0% +polysilicon suppliers didn't really want +to invest unless they knew photovoltaics + + align:start position:0% +to invest unless they knew photovoltaics + + + align:start position:0% +to invest unless they knew photovoltaics +was for real right and the PV industry + + align:start position:0% +was for real right and the PV industry + + + align:start position:0% +was for real right and the PV industry +had exhausted the uh the elasticity of + + align:start position:0% +had exhausted the uh the elasticity of + + + align:start position:0% +had exhausted the uh the elasticity of +the supply market in the uh in the + + align:start position:0% +the supply market in the uh in the + + + align:start position:0% +the supply market in the uh in the +polysilicon business and polyilicon + + align:start position:0% +polysilicon business and polyilicon + + + align:start position:0% +polysilicon business and polyilicon +suppliers looked at the situation and + + align:start position:0% +suppliers looked at the situation and + + + align:start position:0% +suppliers looked at the situation and +say well let's let prices go up a little + + align:start position:0% +say well let's let prices go up a little + + + align:start position:0% +say well let's let prices go up a little +bit it can't hurt us too bad I mean + + align:start position:0% +bit it can't hurt us too bad I mean + + + align:start position:0% +bit it can't hurt us too bad I mean +let's let's we we've been we've been + + align:start position:0% +let's let's we we've been we've been + + + align:start position:0% +let's let's we we've been we've been +starved for several years because of low + + align:start position:0% +starved for several years because of low + + + align:start position:0% +starved for several years because of low +polysilic feed stock prices. Let's let + + align:start position:0% +polysilic feed stock prices. Let's let + + + align:start position:0% +polysilic feed stock prices. Let's let +this um increased demand kind of push + + align:start position:0% +this um increased demand kind of push + + + align:start position:0% +this um increased demand kind of push +prices up a little bit before we really + + align:start position:0% +prices up a little bit before we really + + + align:start position:0% +prices up a little bit before we really +decide what to do. And by the time they + + align:start position:0% +decide what to do. And by the time they + + + align:start position:0% +decide what to do. And by the time they +decided what to do, um there was a lot + + align:start position:0% +decided what to do, um there was a lot + + + align:start position:0% +decided what to do, um there was a lot +of them getting on the market all at + + align:start position:0% +of them getting on the market all at + + + align:start position:0% +of them getting on the market all at +once, which had this effect. Boom. Now, + + align:start position:0% +once, which had this effect. Boom. Now, + + + align:start position:0% +once, which had this effect. Boom. Now, +um it's not only the polysilicon, but + + align:start position:0% +um it's not only the polysilicon, but + + + align:start position:0% +um it's not only the polysilicon, but +also the uh cell manufacturers, the + + align:start position:0% +also the uh cell manufacturers, the + + + align:start position:0% +also the uh cell manufacturers, the +wafer manufacturers that expanded their + + align:start position:0% +wafer manufacturers that expanded their + + + align:start position:0% +wafer manufacturers that expanded their +capacity during this time between 2007 + + align:start position:0% +capacity during this time between 2007 + + + align:start position:0% +capacity during this time between 2007 +and 2010. Now, today's today's most + + align:start position:0% +and 2010. Now, today's today's most + + + align:start position:0% +and 2010. Now, today's today's most +recent price point, as I saw it on uh on + + align:start position:0% +recent price point, as I saw it on uh on + + + align:start position:0% +recent price point, as I saw it on uh on +on one of our our more trusted websites, + + align:start position:0% +on one of our our more trusted websites, + + + align:start position:0% +on one of our our more trusted websites, +put us down at around uh A13, $15 per + + align:start position:0% +put us down at around uh A13, $15 per + + + align:start position:0% +put us down at around uh A13, $15 per +watt peak. So, we're down here. We're + + align:start position:0% +watt peak. So, we're down here. We're + + + align:start position:0% +watt peak. So, we're down here. We're +well below the historical average trend. + + align:start position:0% +well below the historical average trend. + + + align:start position:0% +well below the historical average trend. +We're in an over supply condition right + + align:start position:0% +We're in an over supply condition right + + + align:start position:0% +We're in an over supply condition right +now. Why did the overupp come about? + + align:start position:0% +now. Why did the overupp come about? + + + align:start position:0% +now. Why did the overupp come about? +Well, partly because of this uh under + + align:start position:0% +Well, partly because of this uh under + + + align:start position:0% +Well, partly because of this uh under +supply condition, many people saw an + + align:start position:0% +supply condition, many people saw an + + + align:start position:0% +supply condition, many people saw an +opportunity and said, "Well, we can + + align:start position:0% +opportunity and said, "Well, we can + + + align:start position:0% +opportunity and said, "Well, we can +address that demand. We can grow in this + + align:start position:0% +address that demand. We can grow in this + + + align:start position:0% +address that demand. We can grow in this +this industry right here." To grow in + + align:start position:0% +this industry right here." To grow in + + + align:start position:0% +this industry right here." To grow in +the industry, you need capital, right? + + align:start position:0% +the industry, you need capital, right? + + + align:start position:0% +the industry, you need capital, right? +You need uh access to finances to + + align:start position:0% +You need uh access to finances to + + + align:start position:0% +You need uh access to finances to +expand. What happened in 2008 in western + + align:start position:0% +expand. What happened in 2008 in western + + + align:start position:0% +expand. What happened in 2008 in western +countries and 2008 was more or less when + + align:start position:0% +countries and 2008 was more or less when + + + align:start position:0% +countries and 2008 was more or less when +it really uh + + align:start position:0% +it really uh + + + align:start position:0% +it really uh +the hit the fan if you will um in in in + + align:start position:0% +the hit the fan if you will um in in in + + + align:start position:0% +the hit the fan if you will um in in in +uh United States in particular. What + + align:start position:0% +uh United States in particular. What + + + align:start position:0% +uh United States in particular. What +what what happened in the capital + + align:start position:0% +what what happened in the capital + + + align:start position:0% +what what happened in the capital +markets + + align:start position:0% +markets + + + align:start position:0% +markets +capital was severely restricted because + + align:start position:0% +capital was severely restricted because + + + align:start position:0% +capital was severely restricted because +we're not providing a lot of loans. + + align:start position:0% +we're not providing a lot of loans. + + + align:start position:0% +we're not providing a lot of loans. +Exactly. We had the financial crisis + + align:start position:0% +Exactly. We had the financial crisis + + + align:start position:0% +Exactly. We had the financial crisis +here in the US. And so in the United + + align:start position:0% +here in the US. And so in the United + + + align:start position:0% +here in the US. And so in the United +States, there was a a pull back um of + + align:start position:0% +States, there was a a pull back um of + + + align:start position:0% +States, there was a a pull back um of +lending. Uh the government stepped in + + align:start position:0% +lending. Uh the government stepped in + + + align:start position:0% +lending. Uh the government stepped in +shortly thereafter realizing that this + + align:start position:0% +shortly thereafter realizing that this + + + align:start position:0% +shortly thereafter realizing that this +was going to be an issue. There was the + + align:start position:0% +was going to be an issue. There was the + + + align:start position:0% +was going to be an issue. There was the +ARRA. Does anybody know what that is? + + align:start position:0% +ARRA. Does anybody know what that is? + + + align:start position:0% +ARRA. Does anybody know what that is? +It's not the American Association of + + align:start position:0% +It's not the American Association of + + + align:start position:0% +It's not the American Association of +Retired People. This is very different. + + align:start position:0% +Retired People. This is very different. + + + align:start position:0% +Retired People. This is very different. +A AR is the American Recovery and + + align:start position:0% +A AR is the American Recovery and + + + align:start position:0% +A AR is the American Recovery and +Reinvestment Act, right? This was the + + align:start position:0% +Reinvestment Act, right? This was the + + + align:start position:0% +Reinvestment Act, right? This was the +stimulus act. And this act um actually + + align:start position:0% +stimulus act. And this act um actually + + + align:start position:0% +stimulus act. And this act um actually +did inject a lot of money into or a lot + + align:start position:0% +did inject a lot of money into or a lot + + + align:start position:0% +did inject a lot of money into or a lot +of capital into renewable energy + + align:start position:0% +of capital into renewable energy + + + align:start position:0% +of capital into renewable energy +projects that began hitting in sometime + + align:start position:0% +projects that began hitting in sometime + + + align:start position:0% +projects that began hitting in sometime +between 2009, let's say the beginning uh + + align:start position:0% +between 2009, let's say the beginning uh + + + align:start position:0% +between 2009, let's say the beginning uh +until 2011. And um so in in this period + + align:start position:0% +until 2011. And um so in in this period + + + align:start position:0% +until 2011. And um so in in this period +right over + + align:start position:0% +right over + + + align:start position:0% +right over +here, anybody hear of the word Celindra? + + align:start position:0% +here, anybody hear of the word Celindra? + + + align:start position:0% +here, anybody hear of the word Celindra? +Yeah, you've heard about it, right? Um + + align:start position:0% +Yeah, you've heard about it, right? Um + + + align:start position:0% +Yeah, you've heard about it, right? Um +Celindra was one of the companies that + + align:start position:0% +Celindra was one of the companies that + + + align:start position:0% +Celindra was one of the companies that +received funding under the ARRA, right? + + align:start position:0% +received funding under the ARRA, right? + + + align:start position:0% +received funding under the ARRA, right? +or ARA uh under the stimulus act. Um so + + align:start position:0% +or ARA uh under the stimulus act. Um so + + + align:start position:0% +or ARA uh under the stimulus act. Um so +a lot of interesting things were + + align:start position:0% +a lot of interesting things were + + + align:start position:0% +a lot of interesting things were +happening during this brief little + + align:start position:0% +happening during this brief little + + + align:start position:0% +happening during this brief little +period right here. During uh the mid + + align:start position:0% +period right here. During uh the mid + + + align:start position:0% +period right here. During uh the mid +2000s uh China was getting a lot of bad + + align:start position:0% +2000s uh China was getting a lot of bad + + + align:start position:0% +2000s uh China was getting a lot of bad +rap um by environmental groups um and + + align:start position:0% +rap um by environmental groups um and + + + align:start position:0% +rap um by environmental groups um and +the United States as well for its + + align:start position:0% +the United States as well for its + + + align:start position:0% +the United States as well for its +growing greenhouse gas emissions. there + + align:start position:0% +growing greenhouse gas emissions. there + + + align:start position:0% +growing greenhouse gas emissions. there +was um a growing concern over greenhouse + + align:start position:0% +was um a growing concern over greenhouse + + + align:start position:0% +was um a growing concern over greenhouse +gases uh culminating in the Copenhagen + + align:start position:0% +gases uh culminating in the Copenhagen + + + align:start position:0% +gases uh culminating in the Copenhagen +uh discussions that uh cu uh countries + + align:start position:0% +uh discussions that uh cu uh countries + + + align:start position:0% +uh discussions that uh cu uh countries +especially developing countries had to + + align:start position:0% +especially developing countries had to + + + align:start position:0% +especially developing countries had to +do more uh to reduce their greenhouse + + align:start position:0% +do more uh to reduce their greenhouse + + + align:start position:0% +do more uh to reduce their greenhouse +gas production and uh this of course + + align:start position:0% +gas production and uh this of course + + + align:start position:0% +gas production and uh this of course +invited a wonderful uh tugof war between + + align:start position:0% +invited a wonderful uh tugof war between + + + align:start position:0% +invited a wonderful uh tugof war between +uh developing countries block the the + + align:start position:0% +uh developing countries block the the + + + align:start position:0% +uh developing countries block the the +most progressive of the developing + + align:start position:0% +most progressive of the developing + + + align:start position:0% +most progressive of the developing +countries let's say um normally + + align:start position:0% +countries let's say um normally + + + align:start position:0% +countries let's say um normally +described as bicko um so Brazil, Russia, + + align:start position:0% +described as bicko um so Brazil, Russia, + + + align:start position:0% +described as bicko um so Brazil, Russia, +India, China and other uh including + + align:start position:0% +India, China and other uh including + + + align:start position:0% +India, China and other uh including +South Africa um and uh the developed + + align:start position:0% +South Africa um and uh the developed + + + align:start position:0% +South Africa um and uh the developed +countries and and you can see + + align:start position:0% +countries and and you can see + + + align:start position:0% +countries and and you can see +perspectives uh from both and it's it's + + align:start position:0% +perspectives uh from both and it's it's + + + align:start position:0% +perspectives uh from both and it's it's +wonderful. Uh the uh sophistication of + + align:start position:0% +wonderful. Uh the uh sophistication of + + + align:start position:0% +wonderful. Uh the uh sophistication of +that debate in terms of polyai arguments + + align:start position:0% +that debate in terms of polyai arguments + + + align:start position:0% +that debate in terms of polyai arguments +was just was beautiful to watch. Um on + + align:start position:0% +was just was beautiful to watch. Um on + + + align:start position:0% +was just was beautiful to watch. Um on +one hand you had the developing + + align:start position:0% +one hand you had the developing + + + align:start position:0% +one hand you had the developing +countries that said well wait a second + + align:start position:0% +countries that said well wait a second + + + align:start position:0% +countries that said well wait a second +you folks in the developed world you + + align:start position:0% +you folks in the developed world you + + + align:start position:0% +you folks in the developed world you +used a lot of fossil fuels and the + + align:start position:0% +used a lot of fossil fuels and the + + + align:start position:0% +used a lot of fossil fuels and the +majority of of of the CO2 emissions that + + align:start position:0% +majority of of of the CO2 emissions that + + + align:start position:0% +majority of of of the CO2 emissions that +have occurred to date were from + + align:start position:0% +have occurred to date were from + + + align:start position:0% +have occurred to date were from +developing or developed countries today. + + align:start position:0% +developing or developed countries today. + + + align:start position:0% +developing or developed countries today. +Um, so it's a bit unfair that you're + + align:start position:0% +Um, so it's a bit unfair that you're + + + align:start position:0% +Um, so it's a bit unfair that you're +asking us to reduce our CO2 intensity. + + align:start position:0% +asking us to reduce our CO2 intensity. + + + align:start position:0% +asking us to reduce our CO2 intensity. +Um, because that might hamper our own + + align:start position:0% +Um, because that might hamper our own + + + align:start position:0% +Um, because that might hamper our own +development. Um, why don't you pay + + align:start position:0% +development. Um, why don't you pay + + + align:start position:0% +development. Um, why don't you pay +reparations, right, for the the CO2 that + + align:start position:0% +reparations, right, for the the CO2 that + + + align:start position:0% +reparations, right, for the the CO2 that +you've already emitted and help us + + align:start position:0% +you've already emitted and help us + + + align:start position:0% +you've already emitted and help us +decrease our CO2 intensity? And so + + align:start position:0% +decrease our CO2 intensity? And so + + + align:start position:0% +decrease our CO2 intensity? And so +there's these these beautiful arguments + + align:start position:0% +there's these these beautiful arguments + + + align:start position:0% +there's these these beautiful arguments +being constructed on both sides of the + + align:start position:0% +being constructed on both sides of the + + + align:start position:0% +being constructed on both sides of the +debate. Um, what China decided to do, so + + align:start position:0% +debate. Um, what China decided to do, so + + + align:start position:0% +debate. Um, what China decided to do, so +in the international spectrum, not much + + align:start position:0% +in the international spectrum, not much + + + align:start position:0% +in the international spectrum, not much +happened. Um and that's fairly um sadly + + align:start position:0% +happened. Um and that's fairly um sadly + + + align:start position:0% +happened. Um and that's fairly um sadly +it's fairly typical of of of of today's + + align:start position:0% +it's fairly typical of of of of today's + + + align:start position:0% +it's fairly typical of of of of today's +um would say the larger the body happens + + align:start position:0% +um would say the larger the body happens + + + align:start position:0% +um would say the larger the body happens +to be whether it's uh the federal + + align:start position:0% +to be whether it's uh the federal + + + align:start position:0% +to be whether it's uh the federal +government or the world um u + + align:start position:0% +government or the world um u + + + align:start position:0% +government or the world um u +institutions it seems that things happen + + align:start position:0% +institutions it seems that things happen + + + align:start position:0% +institutions it seems that things happen +at a much slower pace the larger uh the + + align:start position:0% +at a much slower pace the larger uh the + + + align:start position:0% +at a much slower pace the larger uh the +the entity is but at a smaller entity + + align:start position:0% +the entity is but at a smaller entity + + + align:start position:0% +the entity is but at a smaller entity +right for example a state level which + + align:start position:0% +right for example a state level which + + + align:start position:0% +right for example a state level which +we'll see in a few slides in the United + + align:start position:0% +we'll see in a few slides in the United + + + align:start position:0% +we'll see in a few slides in the United +States a lot's happening right now um + + align:start position:0% +States a lot's happening right now um + + + align:start position:0% +States a lot's happening right now um +and within China's central government a + + align:start position:0% +and within China's central government a + + + align:start position:0% +and within China's central government a +lot happened in response to some of that + + align:start position:0% +lot happened in response to some of that + + + align:start position:0% +lot happened in response to some of that +criticism they said + + align:start position:0% +criticism they said + + + align:start position:0% +criticism they said +There's a point um more a point that uh + + align:start position:0% +There's a point um more a point that uh + + + align:start position:0% +There's a point um more a point that uh +fossil fuel emissions really decreases + + align:start position:0% +fossil fuel emissions really decreases + + + align:start position:0% +fossil fuel emissions really decreases +our quality of life. If you look at some + + align:start position:0% +our quality of life. If you look at some + + + align:start position:0% +our quality of life. If you look at some +of the pollution in our cities, that's + + align:start position:0% +of the pollution in our cities, that's + + + align:start position:0% +of the pollution in our cities, that's +not very becoming um you know, we we can + + align:start position:0% +not very becoming um you know, we we can + + + align:start position:0% +not very becoming um you know, we we can +do better. Um and furthermore, we can + + align:start position:0% +do better. Um and furthermore, we can + + + align:start position:0% +do better. Um and furthermore, we can +create jobs for the people who are + + align:start position:0% +create jobs for the people who are + + + align:start position:0% +create jobs for the people who are +flooding our cities from the countryside + + align:start position:0% +flooding our cities from the countryside + + + align:start position:0% +flooding our cities from the countryside +looking for economic opportunity. We can + + align:start position:0% +looking for economic opportunity. We can + + + align:start position:0% +looking for economic opportunity. We can +create new jobs in this industry. um and + + align:start position:0% +create new jobs in this industry. um and + + + align:start position:0% +create new jobs in this industry. um and +we'll do it by uh making capital + + align:start position:0% +we'll do it by uh making capital + + + align:start position:0% +we'll do it by uh making capital +available uh to this new nassent + + align:start position:0% +available uh to this new nassent + + + align:start position:0% +available uh to this new nassent +industry at a time when it's very + + align:start position:0% +industry at a time when it's very + + + align:start position:0% +industry at a time when it's very +difficult to achieve capital or acquire + + align:start position:0% +difficult to achieve capital or acquire + + + align:start position:0% +difficult to achieve capital or acquire +capital in the west in Europe and the + + align:start position:0% +capital in the west in Europe and the + + + align:start position:0% +capital in the west in Europe and the +United States. And so that began + + align:start position:0% +United States. And so that began + + + align:start position:0% +United States. And so that began +happening really in the in the mid uh + + align:start position:0% +happening really in the in the mid uh + + + align:start position:0% +happening really in the in the mid uh +2000s. And um what we'll see in a few + + align:start position:0% +2000s. And um what we'll see in a few + + + align:start position:0% +2000s. And um what we'll see in a few +slides is the massive growth of the + + align:start position:0% +slides is the massive growth of the + + + align:start position:0% +slides is the massive growth of the +Chinese manufacturing market in response + + align:start position:0% +Chinese manufacturing market in response + + + align:start position:0% +Chinese manufacturing market in response +to this uh the availability of capital + + align:start position:0% +to this uh the availability of capital + + + align:start position:0% +to this uh the availability of capital +in those countries. Let me um go back to + + align:start position:0% +in those countries. Let me um go back to + + + align:start position:0% +in those countries. Let me um go back to +a slide that I presented. I think it was + + align:start position:0% +a slide that I presented. I think it was + + + align:start position:0% +a slide that I presented. I think it was +lecture number one uh where we looked at + + align:start position:0% +lecture number one uh where we looked at + + + align:start position:0% +lecture number one uh where we looked at +the cumulative production of PV as a + + align:start position:0% +the cumulative production of PV as a + + + align:start position:0% +the cumulative production of PV as a +function of year. And if we plot this on + + align:start position:0% +function of year. And if we plot this on + + + align:start position:0% +function of year. And if we plot this on +a log linear plot, we can read the + + align:start position:0% +a log linear plot, we can read the + + + align:start position:0% +a log linear plot, we can read the +growth rate uh off of the slope of that + + align:start position:0% +growth rate uh off of the slope of that + + + align:start position:0% +growth rate uh off of the slope of that +curve. Right? So this uh was somewhere + + align:start position:0% +curve. Right? So this uh was somewhere + + + align:start position:0% +curve. Right? So this uh was somewhere +around 10% uh 40% maybe upwards to 60% + + align:start position:0% +around 10% uh 40% maybe upwards to 60% + + + align:start position:0% +around 10% uh 40% maybe upwards to 60% +if you uh depending on on on how what + + align:start position:0% +if you uh depending on on on how what + + + align:start position:0% +if you uh depending on on on how what +what data points you include in those + + align:start position:0% +what data points you include in those + + + align:start position:0% +what data points you include in those +lines. Interestingly back in 1990 if we + + align:start position:0% +lines. Interestingly back in 1990 if we + + + align:start position:0% +lines. Interestingly back in 1990 if we +look at the uh distribution of different + + align:start position:0% +look at the uh distribution of different + + + align:start position:0% +look at the uh distribution of different +technologies multi- crystallin silicon + + align:start position:0% +technologies multi- crystallin silicon + + + align:start position:0% +technologies multi- crystallin silicon +was a third single crystal and silicon + + align:start position:0% +was a third single crystal and silicon + + + align:start position:0% +was a third single crystal and silicon +about a third and thin film technology + + align:start position:0% +about a third and thin film technology + + + align:start position:0% +about a third and thin film technology +namely pushed by amorphous silicon was + + align:start position:0% +namely pushed by amorphous silicon was + + + align:start position:0% +namely pushed by amorphous silicon was +about a third of all manufacturing + + align:start position:0% +about a third of all manufacturing + + + align:start position:0% +about a third of all manufacturing +production in um as a market evolved. + + align:start position:0% +production in um as a market evolved. + + + align:start position:0% +production in um as a market evolved. +Sorry about this. Um there we go. So + + align:start position:0% +Sorry about this. Um there we go. So + + + align:start position:0% +Sorry about this. Um there we go. So +again the different technologies just to + + align:start position:0% +again the different technologies just to + + + align:start position:0% +again the different technologies just to +situate ourselves uh single crystal + + align:start position:0% +situate ourselves uh single crystal + + + align:start position:0% +situate ourselves uh single crystal +multi crystallin and thin films as a + + align:start position:0% +multi crystallin and thin films as a + + + align:start position:0% +multi crystallin and thin films as a +market evolved uh going into the 2000s + + align:start position:0% +market evolved uh going into the 2000s + + + align:start position:0% +market evolved uh going into the 2000s +we saw this type of breakdown u occur + + align:start position:0% +we saw this type of breakdown u occur + + + align:start position:0% +we saw this type of breakdown u occur +right we have silicon or crystal and + + align:start position:0% +right we have silicon or crystal and + + + align:start position:0% +right we have silicon or crystal and +silicon comprising around 85 to 90% of + + align:start position:0% +silicon comprising around 85 to 90% of + + + align:start position:0% +silicon comprising around 85 to 90% of +the market and thin films um not growing + + align:start position:0% +the market and thin films um not growing + + + align:start position:0% +the market and thin films um not growing +as fast as crystal and silicon it was + + align:start position:0% +as fast as crystal and silicon it was + + + align:start position:0% +as fast as crystal and silicon it was +still growing the market overall is is + + align:start position:0% +still growing the market overall is is + + + align:start position:0% +still growing the market overall is is +is going gang busters but crystal and + + align:start position:0% +is going gang busters but crystal and + + + align:start position:0% +is going gang busters but crystal and +silicon technology was growing faster + + align:start position:0% +silicon technology was growing faster + + + align:start position:0% +silicon technology was growing faster +than the others + + align:start position:0% +than the others + + + align:start position:0% +than the others +And in part this was due to the fact + + align:start position:0% +And in part this was due to the fact + + + align:start position:0% +And in part this was due to the fact +that crystal and silicon technology was + + align:start position:0% +that crystal and silicon technology was + + + align:start position:0% +that crystal and silicon technology was +you know a bit cheaper uh than than than + + align:start position:0% +you know a bit cheaper uh than than than + + + align:start position:0% +you know a bit cheaper uh than than than +films at the time largely driven by the + + align:start position:0% +films at the time largely driven by the + + + align:start position:0% +films at the time largely driven by the +efficiency parameter that we had just + + align:start position:0% +efficiency parameter that we had just + + + align:start position:0% +efficiency parameter that we had just +seen in the previous slides and turnkey + + align:start position:0% +seen in the previous slides and turnkey + + + align:start position:0% +seen in the previous slides and turnkey +equipment was available. So if you had + + align:start position:0% +equipment was available. So if you had + + + align:start position:0% +equipment was available. So if you had +capital someplace in the world anywhere + + align:start position:0% +capital someplace in the world anywhere + + + align:start position:0% +capital someplace in the world anywhere +in the world and the labor and + + align:start position:0% +in the world and the labor and + + + align:start position:0% +in the world and the labor and +commodities uh were such that you could + + align:start position:0% +commodities uh were such that you could + + + align:start position:0% +commodities uh were such that you could +compete in the market and the um the + + align:start position:0% +compete in the market and the um the + + + align:start position:0% +compete in the market and the um the +shipping costs weren't ex extremely uh + + align:start position:0% +shipping costs weren't ex extremely uh + + + align:start position:0% +shipping costs weren't ex extremely uh +prohibitive to to get your product to + + align:start position:0% +prohibitive to to get your product to + + + align:start position:0% +prohibitive to to get your product to +the most interesting markets in the + + align:start position:0% +the most interesting markets in the + + + align:start position:0% +the most interesting markets in the +world. um you could compete because you + + align:start position:0% +world. um you could compete because you + + + align:start position:0% +world. um you could compete because you +could buy turnkey equipment. Even if you + + align:start position:0% +could buy turnkey equipment. Even if you + + + align:start position:0% +could buy turnkey equipment. Even if you +knew nothing about how to manufacture a + + align:start position:0% +knew nothing about how to manufacture a + + + align:start position:0% +knew nothing about how to manufacture a +solar cell, knew nothing about + + align:start position:0% +solar cell, knew nothing about + + + align:start position:0% +solar cell, knew nothing about +semiconductors or solid state physics, + + align:start position:0% +semiconductors or solid state physics, + + + align:start position:0% +semiconductors or solid state physics, +what we had discussed here in this + + align:start position:0% +what we had discussed here in this + + + align:start position:0% +what we had discussed here in this +class, you could still go out and buy a + + align:start position:0% +class, you could still go out and buy a + + + align:start position:0% +class, you could still go out and buy a +turnkey manufacturing line and get + + align:start position:0% +turnkey manufacturing line and get + + + align:start position:0% +turnkey manufacturing line and get +technicians to come in and teach you how + + align:start position:0% +technicians to come in and teach you how + + + align:start position:0% +technicians to come in and teach you how +to manufacture solar cells, right? That + + align:start position:0% +to manufacture solar cells, right? That + + + align:start position:0% +to manufacture solar cells, right? That +was the beauty of of these equipment + + align:start position:0% +was the beauty of of these equipment + + + align:start position:0% +was the beauty of of these equipment +companies. And so, uh the equipment + + align:start position:0% +companies. And so, uh the equipment + + + align:start position:0% +companies. And so, uh the equipment +companies specialized in crystal and + + align:start position:0% +companies specialized in crystal and + + + align:start position:0% +companies specialized in crystal and +silicon technologies. And as such, many + + align:start position:0% +silicon technologies. And as such, many + + + align:start position:0% +silicon technologies. And as such, many +of the turnkey lines that grew up um out + + align:start position:0% +of the turnkey lines that grew up um out + + + align:start position:0% +of the turnkey lines that grew up um out +of the uh out of green field uh + + align:start position:0% +of the uh out of green field uh + + + align:start position:0% +of the uh out of green field uh +factories in um especially in in in in + + align:start position:0% +factories in um especially in in in in + + + align:start position:0% +factories in um especially in in in in +China uh Taiwan and other places around + + align:start position:0% +China uh Taiwan and other places around + + + align:start position:0% +China uh Taiwan and other places around +the world leverage these turnkey + + align:start position:0% +the world leverage these turnkey + + + align:start position:0% +the world leverage these turnkey +manufacturers to a great + + align:start position:0% +manufacturers to a great + + + align:start position:0% +manufacturers to a great +extent. Okay, sorry about this. We'll go + + align:start position:0% +extent. Okay, sorry about this. We'll go + + + align:start position:0% +extent. Okay, sorry about this. We'll go +forward. So price, markets, and + + align:start position:0% +forward. So price, markets, and + + + align:start position:0% +forward. So price, markets, and +subsidies, we're going to be looking at + + align:start position:0% +subsidies, we're going to be looking at + + + align:start position:0% +subsidies, we're going to be looking at +um it's a bit of a hodgepodge in the + + align:start position:0% +um it's a bit of a hodgepodge in the + + + align:start position:0% +um it's a bit of a hodgepodge in the +sense that we're addressing cost, price, + + align:start position:0% +sense that we're addressing cost, price, + + + align:start position:0% +sense that we're addressing cost, price, +and manufacturing all together in one + + align:start position:0% +and manufacturing all together in one + + + align:start position:0% +and manufacturing all together in one +big stew. I think that's useful because + + align:start position:0% +big stew. I think that's useful because + + + align:start position:0% +big stew. I think that's useful because +the three are interrelated, right? A + + align:start position:0% +the three are interrelated, right? A + + + align:start position:0% +the three are interrelated, right? A +price is difficult to set without a + + align:start position:0% +price is difficult to set without a + + + align:start position:0% +price is difficult to set without a +cost. and the manufacturing is part of + + align:start position:0% +cost. and the manufacturing is part of + + + align:start position:0% +cost. and the manufacturing is part of +that that story and can help us tease + + align:start position:0% +that that story and can help us tease + + + align:start position:0% +that that story and can help us tease +apart what exactly is going on right now + + align:start position:0% +apart what exactly is going on right now + + + align:start position:0% +apart what exactly is going on right now +with Celindra with solar world and so + + align:start position:0% +with Celindra with solar world and so + + + align:start position:0% +with Celindra with solar world and so +forth. Okay, so let's start with + + align:start position:0% +forth. Okay, so let's start with + + + align:start position:0% +forth. Okay, so let's start with +customer needs just to acquaint + + align:start position:0% +customer needs just to acquaint + + + align:start position:0% +customer needs just to acquaint +ourselves. If we're talking about price, + + align:start position:0% +ourselves. If we're talking about price, + + + align:start position:0% +ourselves. If we're talking about price, +we can't uh divorce price from a c from + + align:start position:0% +we can't uh divorce price from a c from + + + align:start position:0% +we can't uh divorce price from a c from +our customer. And in terms of what our + + align:start position:0% +our customer. And in terms of what our + + + align:start position:0% +our customer. And in terms of what our +customer needs are, we have on-grid + + align:start position:0% +customer needs are, we have on-grid + + + align:start position:0% +customer needs are, we have on-grid +applications that's represented by for + + align:start position:0% +applications that's represented by for + + + align:start position:0% +applications that's represented by for +example a solar system on my house on + + align:start position:0% +example a solar system on my house on + + + align:start position:0% +example a solar system on my house on +the student center. These are systems + + align:start position:0% +the student center. These are systems + + + align:start position:0% +the student center. These are systems +that are tied to the grid and using the + + align:start position:0% +that are tied to the grid and using the + + + align:start position:0% +that are tied to the grid and using the +grid as a battery to store the the + + align:start position:0% +grid as a battery to store the the + + + align:start position:0% +grid as a battery to store the the +excess energy. um off-grid. This + + align:start position:0% +excess energy. um off-grid. This + + + align:start position:0% +excess energy. um off-grid. This +represents for example the lighting + + align:start position:0% +represents for example the lighting + + + align:start position:0% +represents for example the lighting +Africa project here within our our our + + align:start position:0% +Africa project here within our our our + + + align:start position:0% +Africa project here within our our our +uh our class. Uh these are folks who + + align:start position:0% +uh our class. Uh these are folks who + + + align:start position:0% +uh our class. Uh these are folks who +don't have access to an electrical grid + + align:start position:0% +don't have access to an electrical grid + + + align:start position:0% +don't have access to an electrical grid +and who uh need to have that uh + + align:start position:0% +and who uh need to have that uh + + + align:start position:0% +and who uh need to have that uh +electricity there. So while people on + + align:start position:0% +electricity there. So while people on + + + align:start position:0% +electricity there. So while people on +the grid are worried about cents per + + align:start position:0% +the grid are worried about cents per + + + align:start position:0% +the grid are worried about cents per +kilowatt hour, people off the grid might + + align:start position:0% +kilowatt hour, people off the grid might + + + align:start position:0% +kilowatt hour, people off the grid might +be worried about the dollars per hour of + + align:start position:0% +be worried about the dollars per hour of + + + align:start position:0% +be worried about the dollars per hour of +light, right? That might be their metric + + align:start position:0% +light, right? That might be their metric + + + align:start position:0% +light, right? That might be their metric +of of merit. So from the customer's + + align:start position:0% +of of merit. So from the customer's + + + align:start position:0% +of of merit. So from the customer's +perspective, what is their value? What + + align:start position:0% +perspective, what is their value? What + + + align:start position:0% +perspective, what is their value? What +do they get from the solar uh uh PV + + align:start position:0% +do they get from the solar uh uh PV + + + align:start position:0% +do they get from the solar uh uh PV +system on the roof? These parameters + + align:start position:0% +system on the roof? These parameters + + + align:start position:0% +system on the roof? These parameters +under here, underneath each of the + + align:start position:0% +under here, underneath each of the + + + align:start position:0% +under here, underneath each of the +pictures, represent the value parameter. + + align:start position:0% +pictures, represent the value parameter. + + + align:start position:0% +pictures, represent the value parameter. +And again, it's a it's a very cartoonish + + align:start position:0% +And again, it's a it's a very cartoonish + + + align:start position:0% +And again, it's a it's a very cartoonish +way of thinking about it. It's a lot + + align:start position:0% +way of thinking about it. It's a lot + + + align:start position:0% +way of thinking about it. It's a lot +more complex when you start getting into + + align:start position:0% +more complex when you start getting into + + + align:start position:0% +more complex when you start getting into +the weeds and figure out what the + + align:start position:0% +the weeds and figure out what the + + + align:start position:0% +the weeds and figure out what the +customer actually wants. Reliability + + align:start position:0% +customer actually wants. Reliability + + + align:start position:0% +customer actually wants. Reliability +factors in, access to the product, um, + + align:start position:0% +factors in, access to the product, um, + + + align:start position:0% +factors in, access to the product, um, +repair, uh, reliability and so forth + + align:start position:0% +repair, uh, reliability and so forth + + + align:start position:0% +repair, uh, reliability and so forth +factor in as well. There are many + + align:start position:0% +factor in as well. There are many + + + align:start position:0% +factor in as well. There are many +factors that add into value. But what + + align:start position:0% +factors that add into value. But what + + + align:start position:0% +factors that add into value. But what +I've done or what we've done here is is + + align:start position:0% +I've done or what we've done here is is + + + align:start position:0% +I've done or what we've done here is is +emphasize the biggest levers, if you + + align:start position:0% +emphasize the biggest levers, if you + + + align:start position:0% +emphasize the biggest levers, if you +will, and some of the biggest + + align:start position:0% +will, and some of the biggest + + + align:start position:0% +will, and some of the biggest +differences between different + + align:start position:0% +differences between different + + + align:start position:0% +differences between different +applications of PV. Um, if you're + + align:start position:0% +applications of PV. Um, if you're + + + align:start position:0% +applications of PV. Um, if you're +looking at uh the uh solar panels on top + + align:start position:0% +looking at uh the uh solar panels on top + + + align:start position:0% +looking at uh the uh solar panels on top +of the Toyota Prius, um you might not + + align:start position:0% +of the Toyota Prius, um you might not + + + align:start position:0% +of the Toyota Prius, um you might not +really care about the cents per kilowatt + + align:start position:0% +really care about the cents per kilowatt + + + align:start position:0% +really care about the cents per kilowatt +hour because you're paying $20,000 for + + align:start position:0% +hour because you're paying $20,000 for + + + align:start position:0% +hour because you're paying $20,000 for +your car. Um so what's a few extra + + align:start position:0% +your car. Um so what's a few extra + + + align:start position:0% +your car. Um so what's a few extra +dollars here or there, but you might + + align:start position:0% +dollars here or there, but you might + + + align:start position:0% +dollars here or there, but you might +care about the watts per meter squared, + + align:start position:0% +care about the watts per meter squared, + + + align:start position:0% +care about the watts per meter squared, +which is really an efficiency parameter. + + align:start position:0% +which is really an efficiency parameter. + + + align:start position:0% +which is really an efficiency parameter. +You might want it to satisfy a certain + + align:start position:0% +You might want it to satisfy a certain + + + align:start position:0% +You might want it to satisfy a certain +function that it could not do otherwise + + align:start position:0% +function that it could not do otherwise + + + align:start position:0% +function that it could not do otherwise +if the panel was too low efficiency. If + + align:start position:0% +if the panel was too low efficiency. If + + + align:start position:0% +if the panel was too low efficiency. If +you're sending something into outer + + align:start position:0% +you're sending something into outer + + + align:start position:0% +you're sending something into outer +space, again, you might not care about + + align:start position:0% +space, again, you might not care about + + + align:start position:0% +space, again, you might not care about +the manufacturing cost of the panel + + align:start position:0% +the manufacturing cost of the panel + + + align:start position:0% +the manufacturing cost of the panel +because the shipment costs, in other + + align:start position:0% +because the shipment costs, in other + + + align:start position:0% +because the shipment costs, in other +words, the putting it onto the rocket + + align:start position:0% +words, the putting it onto the rocket + + + align:start position:0% +words, the putting it onto the rocket +and setting up outer space is $10,000 + + align:start position:0% +and setting up outer space is $10,000 + + + align:start position:0% +and setting up outer space is $10,000 +per kilogram, right? You might be more + + align:start position:0% +per kilogram, right? You might be more + + + align:start position:0% +per kilogram, right? You might be more +worried about how much does it weigh? + + align:start position:0% +worried about how much does it weigh? + + + align:start position:0% +worried about how much does it weigh? +What is the specific power of the solar + + align:start position:0% +What is the specific power of the solar + + + align:start position:0% +What is the specific power of the solar +panels? Likewise, if you're installing + + align:start position:0% +panels? Likewise, if you're installing + + + align:start position:0% +panels? Likewise, if you're installing +them on a big box company, for example, + + align:start position:0% +them on a big box company, for example, + + + align:start position:0% +them on a big box company, for example, +Walmart or Kmart, and you have a big + + align:start position:0% +Walmart or Kmart, and you have a big + + + align:start position:0% +Walmart or Kmart, and you have a big +flat roof that isn't very strong, isn't + + align:start position:0% +flat roof that isn't very strong, isn't + + + align:start position:0% +flat roof that isn't very strong, isn't +well reinforced, you might care about + + align:start position:0% +well reinforced, you might care about + + + align:start position:0% +well reinforced, you might care about +that parameter as well, or the grams per + + align:start position:0% +that parameter as well, or the grams per + + + align:start position:0% +that parameter as well, or the grams per +meter squared. Um, sure that factors in + + align:start position:0% +meter squared. Um, sure that factors in + + + align:start position:0% +meter squared. Um, sure that factors in +somewhere. Actually, it doesn't. So, um, + + align:start position:0% +somewhere. Actually, it doesn't. So, um, + + + align:start position:0% +somewhere. Actually, it doesn't. So, um, +there are many other parameters that + + align:start position:0% +there are many other parameters that + + + align:start position:0% +there are many other parameters that +that could matter for a particular + + align:start position:0% +that could matter for a particular + + + align:start position:0% +that could matter for a particular +application. Um, dollars per meter + + align:start position:0% +application. Um, dollars per meter + + + align:start position:0% +application. Um, dollars per meter +squared per aesthetics for a building + + align:start position:0% +squared per aesthetics for a building + + + align:start position:0% +squared per aesthetics for a building +integrated system. Um, I've had + + align:start position:0% +integrated system. Um, I've had + + + align:start position:0% +integrated system. Um, I've had +architects come to me and say, "Can you + + align:start position:0% +architects come to me and say, "Can you + + + align:start position:0% +architects come to me and say, "Can you +make a a yellow solar panel? I'd really + + align:start position:0% +make a a yellow solar panel? I'd really + + + align:start position:0% +make a a yellow solar panel? I'd really +like a yellow solar panel." And here I + + align:start position:0% +like a yellow solar panel." And here I + + + align:start position:0% +like a yellow solar panel." And here I +am thinking of the solar spectrum and + + align:start position:0% +am thinking of the solar spectrum and + + + align:start position:0% +am thinking of the solar spectrum and +seeing the biggest the peak of the solar + + align:start position:0% +seeing the biggest the peak of the solar + + + align:start position:0% +seeing the biggest the peak of the solar +spectrum being reflected away from the + + align:start position:0% +spectrum being reflected away from the + + + align:start position:0% +spectrum being reflected away from the +panel into the the observer's eye and + + align:start position:0% +panel into the the observer's eye and + + + align:start position:0% +panel into the the observer's eye and +thinking, "Well, I can make it kind of + + align:start position:0% +thinking, "Well, I can make it kind of + + + align:start position:0% +thinking, "Well, I can make it kind of +dark + + align:start position:0% +dark + + + align:start position:0% +dark +yellowish." Okay, how much are you + + align:start position:0% +yellowish." Okay, how much are you + + + align:start position:0% +yellowish." Okay, how much are you +willing to pay? Um, and uh, you know, + + align:start position:0% +willing to pay? Um, and uh, you know, + + + align:start position:0% +willing to pay? Um, and uh, you know, +there there are many different + + align:start position:0% +there there are many different + + + align:start position:0% +there there are many different +parameters here that matter for the + + align:start position:0% +parameters here that matter for the + + + align:start position:0% +parameters here that matter for the +customer. Um, this one right here is a + + align:start position:0% +customer. Um, this one right here is a + + + align:start position:0% +customer. Um, this one right here is a +concentrator system. So you have these + + align:start position:0% +concentrator system. So you have these + + + align:start position:0% +concentrator system. So you have these +optics that concentrate the light into a + + align:start position:0% +optics that concentrate the light into a + + + align:start position:0% +optics that concentrate the light into a +small little spot. Um and they're + + align:start position:0% +small little spot. Um and they're + + + align:start position:0% +small little spot. Um and they're +looking at the watts per millimeter + + align:start position:0% +looking at the watts per millimeter + + + align:start position:0% +looking at the watts per millimeter +squared, right? A very small device. How + + align:start position:0% +squared, right? A very small device. How + + + align:start position:0% +squared, right? A very small device. How +much power does it output? Um the cost + + align:start position:0% +much power does it output? Um the cost + + + align:start position:0% +much power does it output? Um the cost +of the actual device is almost + + align:start position:0% +of the actual device is almost + + + align:start position:0% +of the actual device is almost +irrelevant. Um it's the power output + + align:start position:0% +irrelevant. Um it's the power output + + + align:start position:0% +irrelevant. Um it's the power output +that matters because uh the majority of + + align:start position:0% +that matters because uh the majority of + + + align:start position:0% +that matters because uh the majority of +the cost is sunk in and all the + + align:start position:0% +the cost is sunk in and all the + + + align:start position:0% +the cost is sunk in and all the +commodity materials around it. All + + align:start position:0% +commodity materials around it. All + + + align:start position:0% +commodity materials around it. All +right. So we're we're getting into this + + align:start position:0% +right. So we're we're getting into this + + + align:start position:0% +right. So we're we're getting into this +because we're going to focus largely on + + align:start position:0% +because we're going to focus largely on + + + align:start position:0% +because we're going to focus largely on +on-grid applications and I'm going to + + align:start position:0% +on-grid applications and I'm going to + + + align:start position:0% +on-grid applications and I'm going to +explain to you why. If you're in the + + align:start position:0% +explain to you why. If you're in the + + + align:start position:0% +explain to you why. If you're in the +Lighting Africa project, you probably + + align:start position:0% +Lighting Africa project, you probably + + + align:start position:0% +Lighting Africa project, you probably +care mostly about that. Um but the + + align:start position:0% +care mostly about that. Um but the + + + align:start position:0% +care mostly about that. Um but the +on-grid applications currently comprise + + align:start position:0% +on-grid applications currently comprise + + + align:start position:0% +on-grid applications currently comprise +95% of the current market. Substitution + + align:start position:0% +95% of the current market. Substitution + + + align:start position:0% +95% of the current market. Substitution +economics. We're substituting um PV with + + align:start position:0% +economics. We're substituting um PV with + + + align:start position:0% +economics. We're substituting um PV with +uh or we're substituting fossil fuel + + align:start position:0% +uh or we're substituting fossil fuel + + + align:start position:0% +uh or we're substituting fossil fuel +based power. Um on average in the United + + align:start position:0% +based power. Um on average in the United + + + align:start position:0% +based power. Um on average in the United +States somewhere around 600 gram of CO2 + + align:start position:0% +States somewhere around 600 gram of CO2 + + + align:start position:0% +States somewhere around 600 gram of CO2 +per kilowatt hour. Um we're substituting + + align:start position:0% +per kilowatt hour. Um we're substituting + + + align:start position:0% +per kilowatt hour. Um we're substituting +that with PV which is on the order of + + align:start position:0% +that with PV which is on the order of + + + align:start position:0% +that with PV which is on the order of +factor of 5 to 20 lower. Um so what + + align:start position:0% +factor of 5 to 20 lower. Um so what + + + align:start position:0% +factor of 5 to 20 lower. Um so what +types of grid electricity will PV + + align:start position:0% +types of grid electricity will PV + + + align:start position:0% +types of grid electricity will PV +substitute? uh what does this mean for + + align:start position:0% +substitute? uh what does this mean for + + + align:start position:0% +substitute? uh what does this mean for +traditional generation companies also + + align:start position:0% +traditional generation companies also + + + align:start position:0% +traditional generation companies also +called genkos and what is the fair + + align:start position:0% +called genkos and what is the fair + + + align:start position:0% +called genkos and what is the fair +selling price for PV electricity very + + align:start position:0% +selling price for PV electricity very + + + align:start position:0% +selling price for PV electricity very +interesting question so in terms of + + align:start position:0% +interesting question so in terms of + + + align:start position:0% +interesting question so in terms of +markets um this is just a breakdown of + + align:start position:0% +markets um this is just a breakdown of + + + align:start position:0% +markets um this is just a breakdown of +off-grid consumer applications and + + align:start position:0% +off-grid consumer applications and + + + align:start position:0% +off-grid consumer applications and +on-grid when I first got into this + + align:start position:0% +on-grid when I first got into this + + + align:start position:0% +on-grid when I first got into this +somewhere around here um it was broken + + align:start position:0% +somewhere around here um it was broken + + + align:start position:0% +somewhere around here um it was broken +down about 50/50 PV on grid and off-grid + + align:start position:0% +down about 50/50 PV on grid and off-grid + + + align:start position:0% +down about 50/50 PV on grid and off-grid +today um today much further down uh + + align:start position:0% +today um today much further down uh + + + align:start position:0% +today um today much further down uh +off-grid applications probably below 10% + + align:start position:0% +off-grid applications probably below 10% + + + align:start position:0% +off-grid applications probably below 10% +% I don't know the precise numbers for + + align:start position:0% +% I don't know the precise numbers for + + + align:start position:0% +% I don't know the precise numbers for +you but it's it's stayed relatively flat + + align:start position:0% +you but it's it's stayed relatively flat + + + align:start position:0% +you but it's it's stayed relatively flat +compared to the growth rate of the + + align:start position:0% +compared to the growth rate of the + + + align:start position:0% +compared to the growth rate of the +on-grid. Um and the reasons for this + + align:start position:0% +on-grid. Um and the reasons for this + + + align:start position:0% +on-grid. Um and the reasons for this +we'll see in a couple of slides. Um + + align:start position:0% +we'll see in a couple of slides. Um + + + align:start position:0% +we'll see in a couple of slides. Um +these are this is the value of PV + + align:start position:0% +these are this is the value of PV + + + align:start position:0% +these are this is the value of PV +electricity uh per a 2008 report. Um if + + align:start position:0% +electricity uh per a 2008 report. Um if + + + align:start position:0% +electricity uh per a 2008 report. Um if +you look at um what is easily + + align:start position:0% +you look at um what is easily + + + align:start position:0% +you look at um what is easily +monetized easily monetized depending on + + align:start position:0% +monetized easily monetized depending on + + + align:start position:0% +monetized easily monetized depending on +the policy in a particular case um you + + align:start position:0% +the policy in a particular case um you + + + align:start position:0% +the policy in a particular case um you +have uh the cost of fuel uh the cost of + + align:start position:0% +have uh the cost of fuel uh the cost of + + + align:start position:0% +have uh the cost of fuel uh the cost of +of capital typically for a power plant. + + align:start position:0% +of capital typically for a power plant. + + + align:start position:0% +of capital typically for a power plant. +Um the CO2 emissions offset this is if + + align:start position:0% +Um the CO2 emissions offset this is if + + + align:start position:0% +Um the CO2 emissions offset this is if +you have a price of carbon notice how + + align:start position:0% +you have a price of carbon notice how + + + align:start position:0% +you have a price of carbon notice how +small it actually is leading a lot of + + align:start position:0% +small it actually is leading a lot of + + + align:start position:0% +small it actually is leading a lot of +people to conclude that maybe carbon + + align:start position:0% +people to conclude that maybe carbon + + + align:start position:0% +people to conclude that maybe carbon +pricing isn't the biggest lever uh for + + align:start position:0% +pricing isn't the biggest lever uh for + + + align:start position:0% +pricing isn't the biggest lever uh for +bringing PV onto the grid. That's a + + align:start position:0% +bringing PV onto the grid. That's a + + + align:start position:0% +bringing PV onto the grid. That's a +whole another discussion. We can have + + align:start position:0% +whole another discussion. We can have + + + align:start position:0% +whole another discussion. We can have +that later. Uh grid losses. These are + + align:start position:0% +that later. Uh grid losses. These are + + + align:start position:0% +that later. Uh grid losses. These are +the transmission and distribution + + align:start position:0% +the transmission and distribution + + + align:start position:0% +the transmission and distribution +losses. The difference between having + + align:start position:0% +losses. The difference between having + + + align:start position:0% +losses. The difference between having +the PV mounted or distributed power + + align:start position:0% +the PV mounted or distributed power + + + align:start position:0% +the PV mounted or distributed power +generation source mounted right on the + + align:start position:0% +generation source mounted right on the + + + align:start position:0% +generation source mounted right on the +site of use as opposed to a centralized + + align:start position:0% +site of use as opposed to a centralized + + + align:start position:0% +site of use as opposed to a centralized +location that has to distribute + + align:start position:0% +location that has to distribute + + + align:start position:0% +location that has to distribute +it. These are much more difficult to + + align:start position:0% +it. These are much more difficult to + + + align:start position:0% +it. These are much more difficult to +monetize and you can add in here health + + align:start position:0% +monetize and you can add in here health + + + align:start position:0% +monetize and you can add in here health +impacts related to emissions and so + + align:start position:0% +impacts related to emissions and so + + + align:start position:0% +impacts related to emissions and so +forth. Um you're you're looking at uh + + align:start position:0% +forth. Um you're you're looking at uh + + + align:start position:0% +forth. Um you're you're looking at uh +the security the reduced risk of having + + align:start position:0% +the security the reduced risk of having + + + align:start position:0% +the security the reduced risk of having +a product on uh producing electricity at + + align:start position:0% +a product on uh producing electricity at + + + align:start position:0% +a product on uh producing electricity at +a certain known price for 20 years. + + align:start position:0% +a certain known price for 20 years. + + + align:start position:0% +a certain known price for 20 years. +You're also looking at um tax bonuses. + + align:start position:0% +You're also looking at um tax bonuses. + + + align:start position:0% +You're also looking at um tax bonuses. +These are are tricky because uh tax + + align:start position:0% +These are are tricky because uh tax + + + align:start position:0% +These are are tricky because uh tax +policy can change. Um you're looking at + + align:start position:0% +policy can change. Um you're looking at + + + align:start position:0% +policy can change. Um you're looking at +uncertainty in your raw feed stock + + align:start position:0% +uncertainty in your raw feed stock + + + align:start position:0% +uncertainty in your raw feed stock +material, the fuel. Um and the need for + + align:start position:0% +material, the fuel. Um and the need for + + + align:start position:0% +material, the fuel. Um and the need for +backup uh is is something that reduces + + align:start position:0% +backup uh is is something that reduces + + + align:start position:0% +backup uh is is something that reduces +the value of PV electricity. Right? If + + align:start position:0% +the value of PV electricity. Right? If + + + align:start position:0% +the value of PV electricity. Right? If +you at some point in the future will + + align:start position:0% +you at some point in the future will + + + align:start position:0% +you at some point in the future will +need to uh back up PV power with + + align:start position:0% +need to uh back up PV power with + + + align:start position:0% +need to uh back up PV power with +something that is uh more dispatchable + + align:start position:0% +something that is uh more dispatchable + + + align:start position:0% +something that is uh more dispatchable +and is still an uncertainty in the power + + align:start position:0% +and is still an uncertainty in the power + + + align:start position:0% +and is still an uncertainty in the power +grid, uh that's something that is um + + align:start position:0% +grid, uh that's something that is um + + + align:start position:0% +grid, uh that's something that is um +reducing the value of installing the PV + + align:start position:0% +reducing the value of installing the PV + + + align:start position:0% +reducing the value of installing the PV +today. Some might argue that that 1 cent + + align:start position:0% +today. Some might argue that that 1 cent + + + align:start position:0% +today. Some might argue that that 1 cent +negative is actually a drastic + + align:start position:0% +negative is actually a drastic + + + align:start position:0% +negative is actually a drastic +underestimation of the risk associated + + align:start position:0% +underestimation of the risk associated + + + align:start position:0% +underestimation of the risk associated +with backup power needs. But this is um + + align:start position:0% +with backup power needs. But this is um + + + align:start position:0% +with backup power needs. But this is um +this is a a fair look at what uh a value + + align:start position:0% +this is a a fair look at what uh a value + + + align:start position:0% +this is a a fair look at what uh a value +the the so-called true value of PV + + align:start position:0% +the the so-called true value of PV + + + align:start position:0% +the the so-called true value of PV +electricity might be which would lead us + + align:start position:0% +electricity might be which would lead us + + + align:start position:0% +electricity might be which would lead us +into pricing right if we know the value + + align:start position:0% +into pricing right if we know the value + + + align:start position:0% +into pricing right if we know the value +we can uh enter pricing and not many + + align:start position:0% +we can uh enter pricing and not many + + + align:start position:0% +we can uh enter pricing and not many +people can argue with this because this + + align:start position:0% +people can argue with this because this + + + align:start position:0% +people can argue with this because this +is substitution economics right this is + + align:start position:0% +is substitution economics right this is + + + align:start position:0% +is substitution economics right this is +just saying okay how much does it cost + + align:start position:0% +just saying okay how much does it cost + + + align:start position:0% +just saying okay how much does it cost +uh to produce pe uh fossil fuel + + align:start position:0% +uh to produce pe uh fossil fuel + + + align:start position:0% +uh to produce pe uh fossil fuel +electricity and let's substitute that um + + align:start position:0% +electricity and let's substitute that um + + + align:start position:0% +electricity and let's substitute that um +anything over here in the yellow is what + + align:start position:0% +anything over here in the yellow is what + + + align:start position:0% +anything over here in the yellow is what +people might say well gee if we really + + align:start position:0% +people might say well gee if we really + + + align:start position:0% +people might say well gee if we really +look at the true price or the true cost + + align:start position:0% +look at the true price or the true cost + + + align:start position:0% +look at the true price or the true cost +of fossil fuels. This is what it really + + align:start position:0% +of fossil fuels. This is what it really + + + align:start position:0% +of fossil fuels. This is what it really +costs if we take away all of the + + align:start position:0% +costs if we take away all of the + + + align:start position:0% +costs if we take away all of the +subsidies and add in all of the + + align:start position:0% +subsidies and add in all of the + + + align:start position:0% +subsidies and add in all of the +externalities. What's an + + align:start position:0% +externalities. What's an + + + align:start position:0% +externalities. What's an +externality? What does an externality + + align:start position:0% +externality? What does an externality + + + align:start position:0% +externality? What does an externality +mean? + + align:start position:0% +mean? + + + align:start position:0% +mean? +An + + align:start position:0% + + + + align:start position:0% + +exter that producer is doing. Yeah. So, + + align:start position:0% +exter that producer is doing. Yeah. So, + + + align:start position:0% +exter that producer is doing. Yeah. So, +when the consumer Oh, or let's put it + + align:start position:0% +when the consumer Oh, or let's put it + + + align:start position:0% +when the consumer Oh, or let's put it +this way. when the + + align:start position:0% +this way. when the + + + align:start position:0% +this way. when the +true impact price impact is not factored + + align:start position:0% +true impact price impact is not factored + + + align:start position:0% +true impact price impact is not factored +into the selling price. Let's + + align:start position:0% + + + + align:start position:0% + +say let's say that um I sell you a + + align:start position:0% +say let's say that um I sell you a + + + align:start position:0% +say let's say that um I sell you a +miracle drug and it allows you to be + + align:start position:0% +miracle drug and it allows you to be + + + align:start position:0% +miracle drug and it allows you to be +five times more productive than you are + + align:start position:0% +five times more productive than you are + + + align:start position:0% +five times more productive than you are +right now. Um, but then every time + + align:start position:0% +right now. Um, but then every time + + + align:start position:0% +right now. Um, but then every time +you have your your needs, um, down the + + align:start position:0% +you have your your needs, um, down the + + + align:start position:0% +you have your your needs, um, down the +toilet goes a bunch of chemicals that + + align:start position:0% +toilet goes a bunch of chemicals that + + + align:start position:0% +toilet goes a bunch of chemicals that +the power that the water plant now needs + + align:start position:0% +the power that the water plant now needs + + + align:start position:0% +the power that the water plant now needs +to, uh, filter out. And the the water + + align:start position:0% +to, uh, filter out. And the the water + + + align:start position:0% +to, uh, filter out. And the the water +plant begins failing some of its, uh, + + align:start position:0% +plant begins failing some of its, uh, + + + align:start position:0% +plant begins failing some of its, uh, +its standard tests when they measure + + align:start position:0% +its standard tests when they measure + + + align:start position:0% +its standard tests when they measure +water quality. So, they add in some more + + align:start position:0% +water quality. So, they add in some more + + + align:start position:0% +water quality. So, they add in some more +filters into their uh, into their + + align:start position:0% +filters into their uh, into their + + + align:start position:0% +filters into their uh, into their +system. They figure out how to get rid + + align:start position:0% +system. They figure out how to get rid + + + align:start position:0% +system. They figure out how to get rid +of this compound. And now all of the + + align:start position:0% +of this compound. And now all of the + + + align:start position:0% +of this compound. And now all of the +water treatment facilities around the + + align:start position:0% +water treatment facilities around the + + + align:start position:0% +water treatment facilities around the +country begin adding in these new + + align:start position:0% +country begin adding in these new + + + align:start position:0% +country begin adding in these new +filters. And it costs somewhere on the + + align:start position:0% +filters. And it costs somewhere on the + + + align:start position:0% +filters. And it costs somewhere on the +order of a billion dollars. That is an + + align:start position:0% +order of a billion dollars. That is an + + + align:start position:0% +order of a billion dollars. That is an +externality, right? That's something + + align:start position:0% +externality, right? That's something + + + align:start position:0% +externality, right? That's something +that wasn't factored into the price of + + align:start position:0% +that wasn't factored into the price of + + + align:start position:0% +that wasn't factored into the price of +selling you that miracle drug that + + align:start position:0% +selling you that miracle drug that + + + align:start position:0% +selling you that miracle drug that +allowed you to be five times more + + align:start position:0% +allowed you to be five times more + + + align:start position:0% +allowed you to be five times more +productive. It's it's an example of of + + align:start position:0% +productive. It's it's an example of of + + + align:start position:0% +productive. It's it's an example of of +how everybody pays for uh the acts or + + align:start position:0% +how everybody pays for uh the acts or + + + align:start position:0% +how everybody pays for uh the acts or +the the the purchases of a few, right? + + align:start position:0% +the the the purchases of a few, right? + + + align:start position:0% +the the the purchases of a few, right? +And that's the case with uh with energy + + align:start position:0% +And that's the case with uh with energy + + + align:start position:0% +And that's the case with uh with energy +production as well. Um so it's it's um + + align:start position:0% +production as well. Um so it's it's um + + + align:start position:0% +production as well. Um so it's it's um +it's difficult to argue in economic + + align:start position:0% +it's difficult to argue in economic + + + align:start position:0% +it's difficult to argue in economic +terms or it's difficult to put a a + + align:start position:0% +terms or it's difficult to put a a + + + align:start position:0% +terms or it's difficult to put a a +specific price on externalities because + + align:start position:0% +specific price on externalities because + + + align:start position:0% +specific price on externalities because +these could be things like premature + + align:start position:0% +these could be things like premature + + + align:start position:0% +these could be things like premature +deaths and there are statistitians who + + align:start position:0% +deaths and there are statistitians who + + + align:start position:0% +deaths and there are statistitians who +will calculate the number of people who + + align:start position:0% +will calculate the number of people who + + + align:start position:0% +will calculate the number of people who +die prematurely as a result of exposure + + align:start position:0% +die prematurely as a result of exposure + + + align:start position:0% +die prematurely as a result of exposure +to uh mercury or or cadmium or some + + align:start position:0% +to uh mercury or or cadmium or some + + + align:start position:0% +to uh mercury or or cadmium or some +other emission coming off of a fossil + + align:start position:0% +other emission coming off of a fossil + + + align:start position:0% +other emission coming off of a fossil +fuel burning plant. But then how do you + + align:start position:0% +fuel burning plant. But then how do you + + + align:start position:0% +fuel burning plant. But then how do you +monetize that? You have to assign a + + align:start position:0% +monetize that? You have to assign a + + + align:start position:0% +monetize that? You have to assign a +value to a human life and say that a + + align:start position:0% +value to a human life and say that a + + + align:start position:0% +value to a human life and say that a +certain economic value was lost uh both + + align:start position:0% +certain economic value was lost uh both + + + align:start position:0% +certain economic value was lost uh both +in terms of productivity costs but also + + align:start position:0% +in terms of productivity costs but also + + + align:start position:0% +in terms of productivity costs but also +in terms of the investment due to that + + align:start position:0% +in terms of the investment due to that + + + align:start position:0% +in terms of the investment due to that +person dying and and and they do that in + + align:start position:0% +person dying and and and they do that in + + + align:start position:0% +person dying and and and they do that in +in government. There is a value to a + + align:start position:0% +in government. There is a value to a + + + align:start position:0% +in government. There is a value to a +human life and it can vary somewhat from + + align:start position:0% +human life and it can vary somewhat from + + + align:start position:0% +human life and it can vary somewhat from +one or from one group to another. Um but + + align:start position:0% +one or from one group to another. Um but + + + align:start position:0% +one or from one group to another. Um but +it it it's it's very difficult to price + + align:start position:0% +it it it's it's very difficult to price + + + align:start position:0% +it it it's it's very difficult to price +in externalities and that's why often + + align:start position:0% +in externalities and that's why often + + + align:start position:0% +in externalities and that's why often +times these things in uh yellow here are + + align:start position:0% +times these things in uh yellow here are + + + align:start position:0% +times these things in uh yellow here are +are neglected are not considered and for + + align:start position:0% +are neglected are not considered and for + + + align:start position:0% +are neglected are not considered and for +the purposes of today's discussion we're + + align:start position:0% +the purposes of today's discussion we're + + + align:start position:0% +the purposes of today's discussion we're +just going to factor in mostly these + + align:start position:0% +just going to factor in mostly these + + + align:start position:0% +just going to factor in mostly these +parameters right here because we have a + + align:start position:0% +parameters right here because we have a + + + align:start position:0% +parameters right here because we have a +greater hold on them right um so in + + align:start position:0% +greater hold on them right um so in + + + align:start position:0% +greater hold on them right um so in +terms of PV installations worldwide + + align:start position:0% +terms of PV installations worldwide + + + align:start position:0% +terms of PV installations worldwide +cumulative I I want to compare and + + align:start position:0% +cumulative I I want to compare and + + + align:start position:0% +cumulative I I want to compare and +contrast where our customers are versus + + align:start position:0% +contrast where our customers are versus + + + align:start position:0% +contrast where our customers are versus +where our manufacturing is and we'll get + + align:start position:0% +where our manufacturing is and we'll get + + + align:start position:0% +where our manufacturing is and we'll get +to some really interesting interesting + + align:start position:0% +to some really interesting interesting + + + align:start position:0% +to some really interesting interesting +questions um associated with that. So + + align:start position:0% +questions um associated with that. So + + + align:start position:0% +questions um associated with that. So +look at look at that um where would you + + align:start position:0% +look at look at that um where would you + + + align:start position:0% +look at look at that um where would you +expect PV to be installed? You'd expect + + align:start position:0% +expect PV to be installed? You'd expect + + + align:start position:0% +expect PV to be installed? You'd expect +it to be installed in the sunniest + + align:start position:0% +it to be installed in the sunniest + + + align:start position:0% +it to be installed in the sunniest +places. Why? Because the amount of + + align:start position:0% +places. Why? Because the amount of + + + align:start position:0% +places. Why? Because the amount of +energy produced is related uh + + align:start position:0% +energy produced is related uh + + + align:start position:0% +energy produced is related uh +proportional to the amount of uh solar + + align:start position:0% +proportional to the amount of uh solar + + + align:start position:0% +proportional to the amount of uh solar +resource that's available in that spot. + + align:start position:0% +resource that's available in that spot. + + + align:start position:0% +resource that's available in that spot. +But from a customer's point of view, + + align:start position:0% +But from a customer's point of view, + + + align:start position:0% +But from a customer's point of view, +solar resource isn't everything. They're + + align:start position:0% +solar resource isn't everything. They're + + + align:start position:0% +solar resource isn't everything. They're +also looking at the cost of + + align:start position:0% +also looking at the cost of + + + align:start position:0% +also looking at the cost of +displacement. how much what is the price + + align:start position:0% +displacement. how much what is the price + + + align:start position:0% +displacement. how much what is the price +of the electricity I'm paying and how + + align:start position:0% +of the electricity I'm paying and how + + + align:start position:0% +of the electricity I'm paying and how +much of that can I displace with my PV + + align:start position:0% +much of that can I displace with my PV + + + align:start position:0% +much of that can I displace with my PV +electricity right so there there there's + + align:start position:0% +electricity right so there there there's + + + align:start position:0% +electricity right so there there there's +a more sophisticated uh uh uh concern + + align:start position:0% +a more sophisticated uh uh uh concern + + + align:start position:0% +a more sophisticated uh uh uh concern +here and further the price of + + align:start position:0% +here and further the price of + + + align:start position:0% +here and further the price of +electricity might not only be dictated + + align:start position:0% +electricity might not only be dictated + + + align:start position:0% +electricity might not only be dictated +by uh the true cost of production of the + + align:start position:0% +by uh the true cost of production of the + + + align:start position:0% +by uh the true cost of production of the +solar power of of the fossil fuel power + + align:start position:0% +solar power of of the fossil fuel power + + + align:start position:0% +solar power of of the fossil fuel power +plants there may be a few governments + + align:start position:0% +plants there may be a few governments + + + align:start position:0% +plants there may be a few governments +out there that say well look at all + + align:start position:0% +out there that say well look at all + + + align:start position:0% +out there that say well look at all +these externalities we want to begin + + align:start position:0% +these externalities we want to begin + + + align:start position:0% +these externalities we want to begin +factoring those in we want to provide an + + align:start position:0% +factoring those in we want to provide an + + + align:start position:0% +factoring those in we want to provide an +incentive for people to produce PV + + align:start position:0% +incentive for people to produce PV + + + align:start position:0% +incentive for people to produce PV +electricity that's commonly referred to + + align:start position:0% +electricity that's commonly referred to + + + align:start position:0% +electricity that's commonly referred to +as a subsidy. So if we look at the total + + align:start position:0% +as a subsidy. So if we look at the total + + + align:start position:0% +as a subsidy. So if we look at the total +installation, EU is really leading the + + align:start position:0% +installation, EU is really leading the + + + align:start position:0% +installation, EU is really leading the +charge here. And we saw in those + + align:start position:0% +charge here. And we saw in those + + + align:start position:0% +charge here. And we saw in those +installation maps, there's not a heck of + + align:start position:0% +installation maps, there's not a heck of + + + align:start position:0% +installation maps, there's not a heck of +a lot of sun there in the EU, right? + + align:start position:0% +a lot of sun there in the EU, right? + + + align:start position:0% +a lot of sun there in the EU, right? +Germany's has has uh solar radiance + + align:start position:0% +Germany's has has uh solar radiance + + + align:start position:0% +Germany's has has uh solar radiance +similar to what we have here in the + + align:start position:0% +similar to what we have here in the + + + align:start position:0% +similar to what we have here in the +northeast of the country. And we know + + align:start position:0% +northeast of the country. And we know + + + align:start position:0% +northeast of the country. And we know +that most of the PV installed in the + + align:start position:0% +that most of the PV installed in the + + + align:start position:0% +that most of the PV installed in the +United States is going into the + + align:start position:0% +United States is going into the + + + align:start position:0% +United States is going into the +southwest. um Japan, uh rest of world, + + align:start position:0% +southwest. um Japan, uh rest of world, + + + align:start position:0% +southwest. um Japan, uh rest of world, +USA, relatively small fraction up there. + + align:start position:0% +USA, relatively small fraction up there. + + + align:start position:0% +USA, relatively small fraction up there. +And China, tiny tiny little bleep. + + align:start position:0% +And China, tiny tiny little bleep. + + + align:start position:0% +And China, tiny tiny little bleep. +China's the peach one right up there at + + align:start position:0% +China's the peach one right up there at + + + align:start position:0% +China's the peach one right up there at +the little top. So I would say less than + + align:start position:0% +the little top. So I would say less than + + + align:start position:0% +the little top. So I would say less than +5% of total installed uh worldwide. + + align:start position:0% +5% of total installed uh worldwide. + + + align:start position:0% +5% of total installed uh worldwide. +Actually, it's this is 1.5%. You can + + align:start position:0% +Actually, it's this is 1.5%. You can + + + align:start position:0% +Actually, it's this is 1.5%. You can +read it off right here. Do the division. + + align:start position:0% +read it off right here. Do the division. + + + align:start position:0% +read it off right here. Do the division. +Okay. So um we have very interesting + + align:start position:0% +Okay. So um we have very interesting + + + align:start position:0% +Okay. So um we have very interesting +perspective here about our customers. Um + + align:start position:0% +perspective here about our customers. Um + + + align:start position:0% +perspective here about our customers. Um +this is a breakdown again in in terms of + + align:start position:0% +this is a breakdown again in in terms of + + + align:start position:0% +this is a breakdown again in in terms of +customers. Again, a little bit uh better + + align:start position:0% +customers. Again, a little bit uh better + + + align:start position:0% +customers. Again, a little bit uh better +detail. Instead of just seeing EU, we're + + align:start position:0% +detail. Instead of just seeing EU, we're + + + align:start position:0% +detail. Instead of just seeing EU, we're +looking at uh a variety of different um + + align:start position:0% +looking at uh a variety of different um + + + align:start position:0% +looking at uh a variety of different um +uh of customers. And this is new + + align:start position:0% +uh of customers. And this is new + + + align:start position:0% +uh of customers. And this is new +installations worldwide. So if, for + + align:start position:0% +installations worldwide. So if, for + + + align:start position:0% +installations worldwide. So if, for +example, this blue bar goes down, that + + align:start position:0% +example, this blue bar goes down, that + + + align:start position:0% +example, this blue bar goes down, that +just means we installed less PV this + + align:start position:0% +just means we installed less PV this + + + align:start position:0% +just means we installed less PV this +year than we did last year. It doesn't + + align:start position:0% +year than we did last year. It doesn't + + + align:start position:0% +year than we did last year. It doesn't +mean that the total amount on the grid + + align:start position:0% +mean that the total amount on the grid + + + align:start position:0% +mean that the total amount on the grid +went down. It's just new new PV + + align:start position:0% +went down. It's just new new PV + + + align:start position:0% +went down. It's just new new PV +installs. So the blue down here is now + + align:start position:0% +installs. So the blue down here is now + + + align:start position:0% +installs. So the blue down here is now +Germany. Um, we have these countries + + align:start position:0% +Germany. Um, we have these countries + + + align:start position:0% +Germany. Um, we have these countries +that are like flashes in the pan. Italy, + + align:start position:0% +that are like flashes in the pan. Italy, + + + align:start position:0% +that are like flashes in the pan. Italy, +for example, right? Uh, sorry, Spain. + + align:start position:0% +for example, right? Uh, sorry, Spain. + + + align:start position:0% +for example, right? Uh, sorry, Spain. +This one, Spain grew up really quick and + + align:start position:0% +This one, Spain grew up really quick and + + + align:start position:0% +This one, Spain grew up really quick and +then disappeared. Italy grew up really + + align:start position:0% +then disappeared. Italy grew up really + + + align:start position:0% +then disappeared. Italy grew up really +quick and then shrinking. Um, if we + + align:start position:0% +quick and then shrinking. Um, if we + + + align:start position:0% +quick and then shrinking. Um, if we +extended it out to 2011, it'd be back to + + align:start position:0% +extended it out to 2011, it'd be back to + + + align:start position:0% +extended it out to 2011, it'd be back to +a very small amount. Um, we have USA + + align:start position:0% +a very small amount. Um, we have USA + + + align:start position:0% +a very small amount. Um, we have USA +that's consistently growing. That's a + + align:start position:0% +that's consistently growing. That's a + + + align:start position:0% +that's consistently growing. That's a +nice healthy market. And Germany that's + + align:start position:0% +nice healthy market. And Germany that's + + + align:start position:0% +nice healthy market. And Germany that's +uh growing as well. Um, wow, what a what + + align:start position:0% +uh growing as well. Um, wow, what a what + + + align:start position:0% +uh growing as well. Um, wow, what a what +an interesting dynamic. Why did Spain + + align:start position:0% +an interesting dynamic. Why did Spain + + + align:start position:0% +an interesting dynamic. Why did Spain +have this flash in the pan and then + + align:start position:0% +have this flash in the pan and then + + + align:start position:0% +have this flash in the pan and then +shrink suddenly? What did they do + + align:start position:0% +shrink suddenly? What did they do + + + align:start position:0% +shrink suddenly? What did they do +differently than Germany did? We'll + + align:start position:0% +differently than Germany did? We'll + + + align:start position:0% +differently than Germany did? We'll +start asking those questions and + + align:start position:0% +start asking those questions and + + + align:start position:0% +start asking those questions and +answering them in a few slides. Um, if + + align:start position:0% +answering them in a few slides. Um, if + + + align:start position:0% +answering them in a few slides. Um, if +you really want to get detailed + + align:start position:0% +you really want to get detailed + + + align:start position:0% +you really want to get detailed +information about the US, where PV is + + align:start position:0% +information about the US, where PV is + + + align:start position:0% +information about the US, where PV is +installed in the United States, um, one + + align:start position:0% +installed in the United States, um, one + + + align:start position:0% +installed in the United States, um, one +of your MIT colleagues and a bunch of, + + align:start position:0% +of your MIT colleagues and a bunch of, + + + align:start position:0% +of your MIT colleagues and a bunch of, +uh, ENL folks got together, uh, and put + + align:start position:0% +uh, ENL folks got together, uh, and put + + + align:start position:0% +uh, ENL folks got together, uh, and put +up this beautiful, + + align:start position:0% +up this beautiful, + + + align:start position:0% +up this beautiful, +uh, archive, if you will, compendex of + + align:start position:0% +uh, archive, if you will, compendex of + + + align:start position:0% +uh, archive, if you will, compendex of +all as as many PV installations as they + + align:start position:0% +all as as many PV installations as they + + + align:start position:0% +all as as many PV installations as they +possibly could in the United States. So, + + align:start position:0% +possibly could in the United States. So, + + + align:start position:0% +possibly could in the United States. So, +that's the website. Unfortunately, I + + align:start position:0% +that's the website. Unfortunately, I + + + align:start position:0% +that's the website. Unfortunately, I +didn't include it in your slides. Um, so + + align:start position:0% +didn't include it in your slides. Um, so + + + align:start position:0% +didn't include it in your slides. Um, so +you might want to write that down if + + align:start position:0% +you might want to write that down if + + + align:start position:0% +you might want to write that down if +you're uh, curious about it. Um, + + align:start position:0% +you're uh, curious about it. Um, + + + align:start position:0% +you're uh, curious about it. Um, +wonderful resource. Uh, again, ENL, the + + align:start position:0% +wonderful resource. Uh, again, ENL, the + + + align:start position:0% +wonderful resource. Uh, again, ENL, the +National Renewable Energy Laboratory + + align:start position:0% +National Renewable Energy Laboratory + + + align:start position:0% +National Renewable Energy Laboratory +based in Golden, Colorado. And, uh, you + + align:start position:0% +based in Golden, Colorado. And, uh, you + + + align:start position:0% +based in Golden, Colorado. And, uh, you +can see the install distribution + + align:start position:0% +can see the install distribution + + + align:start position:0% +can see the install distribution +throughout the United States. Again, a + + align:start position:0% +throughout the United States. Again, a + + + align:start position:0% +throughout the United States. Again, a +bias toward states that have, uh, high + + align:start position:0% +bias toward states that have, uh, high + + + align:start position:0% +bias toward states that have, uh, high +electricity prices like New York in + + align:start position:0% +electricity prices like New York in + + + align:start position:0% +electricity prices like New York in +Massachusetts and lots of sun, uh, like + + align:start position:0% +Massachusetts and lots of sun, uh, like + + + align:start position:0% +Massachusetts and lots of sun, uh, like +Arizona. The, uh, price of electricity + + align:start position:0% +Arizona. The, uh, price of electricity + + + align:start position:0% +Arizona. The, uh, price of electricity +is rather low in Arizona. It's below 10 + + align:start position:0% +is rather low in Arizona. It's below 10 + + + align:start position:0% +is rather low in Arizona. It's below 10 +cents per kilowatt hour, but, um, the + + align:start position:0% +cents per kilowatt hour, but, um, the + + + align:start position:0% +cents per kilowatt hour, but, um, the +amount of sun available is is very high. + + align:start position:0% +amount of sun available is is very high. + + + align:start position:0% +amount of sun available is is very high. +whereas California has both. Okay, so we + + align:start position:0% +whereas California has both. Okay, so we + + + align:start position:0% +whereas California has both. Okay, so we +talked about the customer. Now here + + align:start position:0% +talked about the customer. Now here + + + align:start position:0% +talked about the customer. Now here +we're talking about the manufacturers. + + align:start position:0% +we're talking about the manufacturers. + + + align:start position:0% +we're talking about the manufacturers. +So we have the customers, the demand, + + align:start position:0% +So we have the customers, the demand, + + + align:start position:0% +So we have the customers, the demand, +the manufacturers, the supply. This um + + align:start position:0% +the manufacturers, the supply. This um + + + align:start position:0% +the manufacturers, the supply. This um +obviously the the uh manufacturers are + + align:start position:0% +obviously the the uh manufacturers are + + + align:start position:0% +obviously the the uh manufacturers are +growing at the same rate as our + + align:start position:0% +growing at the same rate as our + + + align:start position:0% +growing at the same rate as our +customers are installing even faster. Uh + + align:start position:0% +customers are installing even faster. Uh + + + align:start position:0% +customers are installing even faster. Uh +mind you, inventory rates are almost + + align:start position:0% +mind you, inventory rates are almost + + + align:start position:0% +mind you, inventory rates are almost +somewhere between 25 and 50% nowadays. + + align:start position:0% +somewhere between 25 and 50% nowadays. + + + align:start position:0% +somewhere between 25 and 50% nowadays. +So um the production has grown faster + + align:start position:0% +So um the production has grown faster + + + align:start position:0% +So um the production has grown faster +than the the the demand has um at least + + align:start position:0% +than the the the demand has um at least + + + align:start position:0% +than the the the demand has um at least +at current prices. Um what we've done + + align:start position:0% +at current prices. Um what we've done + + + align:start position:0% +at current prices. Um what we've done +right here or what what is done right + + align:start position:0% +right here or what what is done right + + + align:start position:0% +right here or what what is done right +here is is a normalization um by market + + align:start position:0% +here is is a normalization um by market + + + align:start position:0% +here is is a normalization um by market +share just to demonstrate how the market + + align:start position:0% +share just to demonstrate how the market + + + align:start position:0% +share just to demonstrate how the market +dynamics are changing as the industry + + align:start position:0% +dynamics are changing as the industry + + + align:start position:0% +dynamics are changing as the industry +grows. So from 2005 to 2009 this doesn't + + align:start position:0% +grows. So from 2005 to 2009 this doesn't + + + align:start position:0% +grows. So from 2005 to 2009 this doesn't +mean that the industry stayed flat. It + + align:start position:0% +mean that the industry stayed flat. It + + + align:start position:0% +mean that the industry stayed flat. It +continued growing at a breakneck pace + + align:start position:0% +continued growing at a breakneck pace + + + align:start position:0% +continued growing at a breakneck pace +but uh the um the countries which + + align:start position:0% +but uh the um the countries which + + + align:start position:0% +but uh the um the countries which +comprise the manufacturers have changed + + align:start position:0% +comprise the manufacturers have changed + + + align:start position:0% +comprise the manufacturers have changed +significantly. So let's look at Europe + + align:start position:0% +significantly. So let's look at Europe + + + align:start position:0% +significantly. So let's look at Europe +first off. Europe pretty much you know + + align:start position:0% +first off. Europe pretty much you know + + + align:start position:0% +first off. Europe pretty much you know +started really feeling it during the + + align:start position:0% +started really feeling it during the + + + align:start position:0% +started really feeling it during the +financial crisis. uh they couldn't keep + + align:start position:0% +financial crisis. uh they couldn't keep + + + align:start position:0% +financial crisis. uh they couldn't keep +uh expanding um uh in 2008 uh and then + + align:start position:0% +uh expanding um uh in 2008 uh and then + + + align:start position:0% +uh expanding um uh in 2008 uh and then +when prices really started to drop uh + + align:start position:0% +when prices really started to drop uh + + + align:start position:0% +when prices really started to drop uh +2009 as we saw they didn't continue + + align:start position:0% +2009 as we saw they didn't continue + + + align:start position:0% +2009 as we saw they didn't continue +expanding um were a bit uncompetitive um + + align:start position:0% +expanding um were a bit uncompetitive um + + + align:start position:0% +expanding um were a bit uncompetitive um +US shown here in the uh green again + + align:start position:0% +US shown here in the uh green again + + + align:start position:0% +US shown here in the uh green again +dropping uh India uh I guess sort of uh + + align:start position:0% +dropping uh India uh I guess sort of uh + + + align:start position:0% +dropping uh India uh I guess sort of uh +growing now it's definitely on the + + align:start position:0% +growing now it's definitely on the + + + align:start position:0% +growing now it's definitely on the +upswing Japan decreased considerably + + align:start position:0% +upswing Japan decreased considerably + + + align:start position:0% +upswing Japan decreased considerably +considerably + + align:start position:0% +considerably + + + align:start position:0% +considerably +During the 1990s um in the early 2000s, + + align:start position:0% +During the 1990s um in the early 2000s, + + + align:start position:0% +During the 1990s um in the early 2000s, +Japan had the largest solar company in + + align:start position:0% +Japan had the largest solar company in + + + align:start position:0% +Japan had the largest solar company in +the world, Sharp, better known for micro + + align:start position:0% +the world, Sharp, better known for micro + + + align:start position:0% +the world, Sharp, better known for micro +electronics that you might find around + + align:start position:0% +electronics that you might find around + + + align:start position:0% +electronics that you might find around +your house. Um somehow some way did the + + align:start position:0% +your house. Um somehow some way did the + + + align:start position:0% +your house. Um somehow some way did the +executives at Sharp saw this coming, saw + + align:start position:0% +executives at Sharp saw this coming, saw + + + align:start position:0% +executives at Sharp saw this coming, saw +a huge rise in demand coming from Europe + + align:start position:0% +a huge rise in demand coming from Europe + + + align:start position:0% +a huge rise in demand coming from Europe +and ramped up capacity in Japan. And + + align:start position:0% +and ramped up capacity in Japan. And + + + align:start position:0% +and ramped up capacity in Japan. And +when they did that, they were able to + + align:start position:0% +when they did that, they were able to + + + align:start position:0% +when they did that, they were able to +address large portions of that. They + + align:start position:0% +address large portions of that. They + + + align:start position:0% +address large portions of that. They +made a healthy profit for several years + + align:start position:0% +made a healthy profit for several years + + + align:start position:0% +made a healthy profit for several years +and then they just stopped expanding in + + align:start position:0% +and then they just stopped expanding in + + + align:start position:0% +and then they just stopped expanding in +PV. Part of it might have been they saw + + align:start position:0% +PV. Part of it might have been they saw + + + align:start position:0% +PV. Part of it might have been they saw +the market dynamics changing. They saw + + align:start position:0% +the market dynamics changing. They saw + + + align:start position:0% +the market dynamics changing. They saw +um their costs, their manufacturing + + align:start position:0% +um their costs, their manufacturing + + + align:start position:0% +um their costs, their manufacturing +costs relative to for example China. + + align:start position:0% +costs relative to for example China. + + + align:start position:0% +costs relative to for example China. +This is the orange right here. Um and + + align:start position:0% +This is the orange right here. Um and + + + align:start position:0% +This is the orange right here. Um and +Taiwan uh in the uh above China above + + align:start position:0% +Taiwan uh in the uh above China above + + + align:start position:0% +Taiwan uh in the uh above China above +the orange and comprised today this is + + align:start position:0% +the orange and comprised today this is + + + align:start position:0% +the orange and comprised today this is +2009 numbers. If we fast forward to + + align:start position:0% +2009 numbers. If we fast forward to + + + align:start position:0% +2009 numbers. If we fast forward to +today in 2011, China and Taiwan comprise + + align:start position:0% +today in 2011, China and Taiwan comprise + + + align:start position:0% +today in 2011, China and Taiwan comprise +55 to 60% of the PV industry worldwide + + align:start position:0% +55 to 60% of the PV industry worldwide + + + align:start position:0% +55 to 60% of the PV industry worldwide +production, manufacturing, + + align:start position:0% +production, manufacturing, + + + align:start position:0% +production, manufacturing, +production. So what does that mean? + + align:start position:0% +production. So what does that mean? + + + align:start position:0% +production. So what does that mean? +Let's explore together some of the uh + + align:start position:0% +Let's explore together some of the uh + + + align:start position:0% +Let's explore together some of the uh +the interesting um results of that. Um + + align:start position:0% +the interesting um results of that. Um + + + align:start position:0% +the interesting um results of that. Um +let's let's look at some of the good + + align:start position:0% +let's let's look at some of the good + + + align:start position:0% +let's let's look at some of the good +things. Um what are some of the good + + align:start position:0% +things. Um what are some of the good + + + align:start position:0% +things. Um what are some of the good +things about um production going to uh + + align:start position:0% +things about um production going to uh + + + align:start position:0% +things about um production going to uh +China and uh Taiwan from say Europe and + + align:start position:0% +China and uh Taiwan from say Europe and + + + align:start position:0% +China and uh Taiwan from say Europe and +the United States of solar panels? Let's + + align:start position:0% +the United States of solar panels? Let's + + + align:start position:0% +the United States of solar panels? Let's +look at that for a sec. So we'll look at + + align:start position:0% +look at that for a sec. So we'll look at + + + align:start position:0% +look at that for a sec. So we'll look at +the glass half full perspective. What + + align:start position:0% +the glass half full perspective. What + + + align:start position:0% +the glass half full perspective. What +are some of the good things? Yeah. More + + align:start position:0% +are some of the good things? Yeah. More + + + align:start position:0% +are some of the good things? Yeah. More +likely that these developing countries + + align:start position:0% +likely that these developing countries + + + align:start position:0% +likely that these developing countries +will use solar panels. More likely the + + align:start position:0% +will use solar panels. More likely the + + + align:start position:0% +will use solar panels. More likely the +developing countries will use solar + + align:start position:0% +developing countries will use solar + + + align:start position:0% +developing countries will use solar +panels. Well um was that the case over + + align:start position:0% +panels. Well um was that the case over + + + align:start position:0% +panels. Well um was that the case over +here? Not really. Right. It's growing. + + align:start position:0% +here? Not really. Right. It's growing. + + + align:start position:0% +here? Not really. Right. It's growing. +it's going um okay uh I suppose if the + + align:start position:0% +it's going um okay uh I suppose if the + + + align:start position:0% +it's going um okay uh I suppose if the +technology is available there um maybe + + align:start position:0% +technology is available there um maybe + + + align:start position:0% +technology is available there um maybe +the technology quite isn't isn't quite + + align:start position:0% +the technology quite isn't isn't quite + + + align:start position:0% +the technology quite isn't isn't quite +cost competitive with local um + + align:start position:0% +cost competitive with local um + + + align:start position:0% +cost competitive with local um +electricity yet so there isn't that + + align:start position:0% +electricity yet so there isn't that + + + align:start position:0% +electricity yet so there isn't that +demand pull locally um maybe the + + align:start position:0% +demand pull locally um maybe the + + + align:start position:0% +demand pull locally um maybe the +realization is that well goodness we can + + align:start position:0% +realization is that well goodness we can + + + align:start position:0% +realization is that well goodness we can +address this European market they're + + align:start position:0% +address this European market they're + + + align:start position:0% +address this European market they're +willing to pay a lot more for the panels + + align:start position:0% +willing to pay a lot more for the panels + + + align:start position:0% +willing to pay a lot more for the panels +than we are um so we might as well + + align:start position:0% +than we are um so we might as well + + + align:start position:0% +than we are um so we might as well +export right now but at some point in + + align:start position:0% +export right now but at some point in + + + align:start position:0% +export right now but at some point in +the future we might be able to satisfy + + align:start position:0% +the future we might be able to satisfy + + + align:start position:0% +the future we might be able to satisfy +internal demand yeah and there are + + align:start position:0% +internal demand yeah and there are + + + align:start position:0% +internal demand yeah and there are +gigawatt plants PV installs going up in + + align:start position:0% +gigawatt plants PV installs going up in + + + align:start position:0% +gigawatt plants PV installs going up in +China right now. Um in part uh due to + + align:start position:0% +China right now. Um in part uh due to + + + align:start position:0% +China right now. Um in part uh due to +increased electricity demand, in part + + align:start position:0% +increased electricity demand, in part + + + align:start position:0% +increased electricity demand, in part +due to weakening demand elsewhere in the + + align:start position:0% +due to weakening demand elsewhere in the + + + align:start position:0% +due to weakening demand elsewhere in the +world and a very large manufacturing + + align:start position:0% +world and a very large manufacturing + + + align:start position:0% +world and a very large manufacturing +base in China that has to put their + + align:start position:0% +base in China that has to put their + + + align:start position:0% +base in China that has to put their +panels out somewhere, right? U so there + + align:start position:0% +panels out somewhere, right? U so there + + + align:start position:0% +panels out somewhere, right? U so there +is um yes adoption. I'll I'll I'll seed + + align:start position:0% +is um yes adoption. I'll I'll I'll seed + + + align:start position:0% +is um yes adoption. I'll I'll I'll seed +that point. Uh yeah, lower cost for the + + align:start position:0% +that point. Uh yeah, lower cost for the + + + align:start position:0% +that point. Uh yeah, lower cost for the +consumer. Lower lower cost for the + + align:start position:0% +consumer. Lower lower cost for the + + + align:start position:0% +consumer. Lower lower cost for the +consumer. Yes. So in uh in the United + + align:start position:0% +consumer. Yes. So in uh in the United + + + align:start position:0% +consumer. Yes. So in uh in the United +States, if we look at the price of + + align:start position:0% +States, if we look at the price of + + + align:start position:0% +States, if we look at the price of +installing a PV system in the United + + align:start position:0% +installing a PV system in the United + + + align:start position:0% +installing a PV system in the United +States, uh the uh price of installing + + align:start position:0% +States, uh the uh price of installing + + + align:start position:0% +States, uh the uh price of installing +the PV system is around + + align:start position:0% +the PV system is around + + + align:start position:0% +the PV system is around +$520 on your roof uh today. The cost of + + align:start position:0% +$520 on your roof uh today. The cost of + + + align:start position:0% +$520 on your roof uh today. The cost of +buying the module is around $1.3, + + align:start position:0% +buying the module is around $1.3, + + + align:start position:0% +buying the module is around $1.3, +$15 from China, right? And so that means + + align:start position:0% +$15 from China, right? And so that means + + + align:start position:0% +$15 from China, right? And so that means +that 80% of the profit margin right now + + align:start position:0% +that 80% of the profit margin right now + + + align:start position:0% +that 80% of the profit margin right now +is being gobbled up by a US company, + + align:start position:0% +is being gobbled up by a US company, + + + align:start position:0% +is being gobbled up by a US company, +right? Um, the price came down. Let's + + align:start position:0% +right? Um, the price came down. Let's + + + align:start position:0% +right? Um, the price came down. Let's +see. When when I installed the panels on + + align:start position:0% +see. When when I installed the panels on + + + align:start position:0% +see. When when I installed the panels on +my roof, uh, got a little bit of a + + align:start position:0% +my roof, uh, got a little bit of a + + + align:start position:0% +my roof, uh, got a little bit of a +better deal, but I would say the average + + align:start position:0% +better deal, but I would say the average + + + align:start position:0% +better deal, but I would say the average +uh, price for a PV system in 2007 must + + align:start position:0% +uh, price for a PV system in 2007 must + + + align:start position:0% +uh, price for a PV system in 2007 must +have been somewhere around $8, uh, per + + align:start position:0% +have been somewhere around $8, uh, per + + + align:start position:0% +have been somewhere around $8, uh, per +watt peak. And now the price is down at + + align:start position:0% +watt peak. And now the price is down at + + + align:start position:0% +watt peak. And now the price is down at +around 520. That said, in Europe, in + + align:start position:0% +around 520. That said, in Europe, in + + + align:start position:0% +around 520. That said, in Europe, in +Germany, uh, which has 10 times more + + align:start position:0% +Germany, uh, which has 10 times more + + + align:start position:0% +Germany, uh, which has 10 times more +installed PV than than the US does, um, + + align:start position:0% +installed PV than than the US does, um, + + + align:start position:0% +installed PV than than the US does, um, +the price of installing PV system on + + align:start position:0% +the price of installing PV system on + + + align:start position:0% +the price of installing PV system on +your roof, uh, could be below €3 per + + align:start position:0% +your roof, uh, could be below €3 per + + + align:start position:0% +your roof, uh, could be below €3 per +watt peak, right? So, the the price is + + align:start position:0% +watt peak, right? So, the the price is + + + align:start position:0% +watt peak, right? So, the the price is +lower because the profit margin that the + + align:start position:0% +lower because the profit margin that the + + + align:start position:0% +lower because the profit margin that the +installers are getting right now is + + align:start position:0% +installers are getting right now is + + + align:start position:0% +installers are getting right now is +smaller. So, yes, absolutely lower cost + + align:start position:0% +smaller. So, yes, absolutely lower cost + + + align:start position:0% +smaller. So, yes, absolutely lower cost +product in US markets. uh that isn't the + + align:start position:0% +product in US markets. uh that isn't the + + + align:start position:0% +product in US markets. uh that isn't the +whole story about what you're going to + + align:start position:0% +whole story about what you're going to + + + align:start position:0% +whole story about what you're going to +pay because there's still the installer + + align:start position:0% +pay because there's still the installer + + + align:start position:0% +pay because there's still the installer +that's stuck in between the Chinese + + align:start position:0% +that's stuck in between the Chinese + + + align:start position:0% +that's stuck in between the Chinese +manufacturer of the module and you right + + align:start position:0% +manufacturer of the module and you right + + + align:start position:0% +manufacturer of the module and you right +serving as the middle person uh + + align:start position:0% +serving as the middle person uh + + + align:start position:0% +serving as the middle person uh +providing you value still but but still + + align:start position:0% +providing you value still but but still + + + align:start position:0% +providing you value still but but still +um extracting a very large profit right + + align:start position:0% +um extracting a very large profit right + + + align:start position:0% +um extracting a very large profit right +now uh a disproportionately large profit + + align:start position:0% +now uh a disproportionately large profit + + + align:start position:0% +now uh a disproportionately large profit +shall I say um what are some of the + + align:start position:0% +shall I say um what are some of the + + + align:start position:0% +shall I say um what are some of the +other good things + + align:start position:0% +other good things + + + align:start position:0% +other good things +if uh cost in big markets is reduced + + align:start position:0% +if uh cost in big markets is reduced + + + align:start position:0% +if uh cost in big markets is reduced +that lead to more market penetration + + align:start position:0% +that lead to more market penetration + + + align:start position:0% +that lead to more market penetration +then the product is just adopted more + + align:start position:0% +then the product is just adopted more + + + align:start position:0% +then the product is just adopted more +and even a price to go up, it might + + align:start position:0% +and even a price to go up, it might + + + align:start position:0% +and even a price to go up, it might +maintain. + + align:start position:0% +maintain. + + + align:start position:0% +maintain. +Yep. And so what what what you're + + align:start position:0% +Yep. And so what what what you're + + + align:start position:0% +Yep. And so what what what you're +leading to here is is really what the + + align:start position:0% +leading to here is is really what the + + + align:start position:0% +leading to here is is really what the +demand curve of PV looks like. And in + + align:start position:0% +demand curve of PV looks like. And in + + + align:start position:0% +demand curve of PV looks like. And in +the past, uh if you look at uh what + + align:start position:0% +the past, uh if you look at uh what + + + align:start position:0% +the past, uh if you look at uh what +people are willing to pay for PV, uh + + align:start position:0% +people are willing to pay for PV, uh + + + align:start position:0% +people are willing to pay for PV, uh +let's say let's convert it into dollars + + align:start position:0% +let's say let's convert it into dollars + + + align:start position:0% +let's say let's convert it into dollars +per watt peak since that's the universal + + align:start position:0% +per watt peak since that's the universal + + + align:start position:0% +per watt peak since that's the universal +unit of of PV uh cost. Um and this is + + align:start position:0% +unit of of PV uh cost. Um and this is + + + align:start position:0% +unit of of PV uh cost. Um and this is +the uh let's call it total market + + align:start position:0% + + + + align:start position:0% + +size in terms of watt peak um and this + + align:start position:0% +size in terms of watt peak um and this + + + align:start position:0% +size in terms of watt peak um and this +being a very very large number what you + + align:start position:0% +being a very very large number what you + + + align:start position:0% +being a very very large number what you +can do to first order just how how would + + align:start position:0% +can do to first order just how how would + + + align:start position:0% +can do to first order just how how would +we construct the demand curve for the + + align:start position:0% +we construct the demand curve for the + + + align:start position:0% +we construct the demand curve for the +United States for PV how would we go + + align:start position:0% +United States for PV how would we go + + + align:start position:0% +United States for PV how would we go +about doing + + align:start position:0% +about doing + + + align:start position:0% +about doing +that how much are people willing to pay + + align:start position:0% +that how much are people willing to pay + + + align:start position:0% +that how much are people willing to pay +for their PV modules to offset the cost + + align:start position:0% +for their PV modules to offset the cost + + + align:start position:0% +for their PV modules to offset the cost +of electricity well to do it right we + + align:start position:0% +of electricity well to do it right we + + + align:start position:0% +of electricity well to do it right we +need a levelized cost of electricity + + align:start position:0% +need a levelized cost of electricity + + + align:start position:0% +need a levelized cost of electricity +analysis we'd assume We're borrowing + + align:start position:0% +analysis we'd assume We're borrowing + + + align:start position:0% +analysis we'd assume We're borrowing +money from the bank, do those fancy + + align:start position:0% +money from the bank, do those fancy + + + align:start position:0% +money from the bank, do those fancy +economics that involve uh you know + + align:start position:0% +economics that involve uh you know + + + align:start position:0% +economics that involve uh you know +something to the power of something and + + align:start position:0% +something to the power of something and + + + align:start position:0% +something to the power of something and +and that being the interest rate uh and + + align:start position:0% +and that being the interest rate uh and + + + align:start position:0% +and that being the interest rate uh and +then we we calculate it through just a + + align:start position:0% +then we we calculate it through just a + + + align:start position:0% +then we we calculate it through just a +first order hand wavy Mickey Mousey we + + align:start position:0% +first order hand wavy Mickey Mousey we + + + align:start position:0% +first order hand wavy Mickey Mousey we +might take into consideration the + + align:start position:0% +might take into consideration the + + + align:start position:0% +might take into consideration the +manufacturing cost of the module sorry + + align:start position:0% +manufacturing cost of the module sorry + + + align:start position:0% +manufacturing cost of the module sorry +back up one step we might take into + + align:start position:0% +back up one step we might take into + + + align:start position:0% +back up one step we might take into +consideration the cents per kilowatt + + align:start position:0% +consideration the cents per kilowatt + + + align:start position:0% +consideration the cents per kilowatt +hour of the electricity that we're uh + + align:start position:0% +hour of the electricity that we're uh + + + align:start position:0% +hour of the electricity that we're uh +getting from the grid and the insulation + + align:start position:0% +getting from the grid and the insulation + + + align:start position:0% +getting from the grid and the insulation +the solar resource that is available at + + align:start position:0% +the solar resource that is available at + + + align:start position:0% +the solar resource that is available at +that particular location. So we if we + + align:start position:0% +that particular location. So we if we + + + align:start position:0% +that particular location. So we if we +have data granular to the state level of + + align:start position:0% +have data granular to the state level of + + + align:start position:0% +have data granular to the state level of +the price of electricity on average + + align:start position:0% +the price of electricity on average + + + align:start position:0% +the price of electricity on average +throughout the state and the solar + + align:start position:0% +throughout the state and the solar + + + align:start position:0% +throughout the state and the solar +resource availability on average + + align:start position:0% +resource availability on average + + + align:start position:0% +resource availability on average +throughout the state we can immediately + + align:start position:0% +throughout the state we can immediately + + + align:start position:0% +throughout the state we can immediately +comprise 150 markets in the US + + align:start position:0% +comprise 150 markets in the US + + + align:start position:0% +comprise 150 markets in the US +residential commercial industrial right + + align:start position:0% +residential commercial industrial right + + + align:start position:0% +residential commercial industrial right +for 50 states and then we'll have a + + align:start position:0% +for 50 states and then we'll have a + + + align:start position:0% +for 50 states and then we'll have a +demand curve very simple one for how + + align:start position:0% +demand curve very simple one for how + + + align:start position:0% +demand curve very simple one for how +much people are willing to pay for their + + align:start position:0% +much people are willing to pay for their + + + align:start position:0% +much people are willing to pay for their +PV electricity and it looks more or less + + align:start position:0% +PV electricity and it looks more or less + + + align:start position:0% +PV electricity and it looks more or less +like this if you start working it + + align:start position:0% +like this if you start working it + + + align:start position:0% +like this if you start working it +out rough sketch rough sketch this is + + align:start position:0% +out rough sketch rough sketch this is + + + align:start position:0% +out rough sketch rough sketch this is +Hawaii. Those poor critters over there, + + align:start position:0% +Hawaii. Those poor critters over there, + + + align:start position:0% +Hawaii. Those poor critters over there, +although they have beautiful sun and + + align:start position:0% +although they have beautiful sun and + + + align:start position:0% +although they have beautiful sun and +enjoy a wonderful life, they're paying a + + align:start position:0% +enjoy a wonderful life, they're paying a + + + align:start position:0% +enjoy a wonderful life, they're paying a +lot for their energy because they're on + + align:start position:0% +lot for their energy because they're on + + + align:start position:0% +lot for their energy because they're on +a few rocks out there, they have no + + align:start position:0% +a few rocks out there, they have no + + + align:start position:0% +a few rocks out there, they have no +natural resource under the ground to + + align:start position:0% +natural resource under the ground to + + + align:start position:0% +natural resource under the ground to +speak of, except geothermal, I suppose. + + align:start position:0% +speak of, except geothermal, I suppose. + + + align:start position:0% +speak of, except geothermal, I suppose. +Um, but uh they're shipping in a lot of + + align:start position:0% +Um, but uh they're shipping in a lot of + + + align:start position:0% +Um, but uh they're shipping in a lot of +their fuel. That's why if you've ever + + align:start position:0% +their fuel. That's why if you've ever + + + align:start position:0% +their fuel. That's why if you've ever +gone to Hawaii and rented a car, you are + + align:start position:0% +gone to Hawaii and rented a car, you are + + + align:start position:0% +gone to Hawaii and rented a car, you are +surprised at this the sticker shock when + + align:start position:0% +surprised at this the sticker shock when + + + align:start position:0% +surprised at this the sticker shock when +you go up to the gas station and try to + + align:start position:0% +you go up to the gas station and try to + + + align:start position:0% +you go up to the gas station and try to +refuel. Um, their uh price of + + align:start position:0% +refuel. Um, their uh price of + + + align:start position:0% +refuel. Um, their uh price of +electricity is above 30 cents per + + align:start position:0% +electricity is above 30 cents per + + + align:start position:0% +electricity is above 30 cents per +kilowatt hour residential. + + align:start position:0% +kilowatt hour residential. + + + align:start position:0% +kilowatt hour residential. +Um, but it's a very very tiny market. + + align:start position:0% +Um, but it's a very very tiny market. + + + align:start position:0% +Um, but it's a very very tiny market. +So, you're not going to be able to + + align:start position:0% +So, you're not going to be able to + + + align:start position:0% +So, you're not going to be able to +satisfy much demand. You're not going to + + align:start position:0% +satisfy much demand. You're not going to + + + align:start position:0% +satisfy much demand. You're not going to +be a prod produce too many panels there. + + align:start position:0% +be a prod produce too many panels there. + + + align:start position:0% +be a prod produce too many panels there. +You start having interesting thing hap + + align:start position:0% +You start having interesting thing hap + + + align:start position:0% +You start having interesting thing hap +things happen when you start hitting the + + align:start position:0% +things happen when you start hitting the + + + align:start position:0% +things happen when you start hitting the +bigger markets like the tiers four and + + align:start position:0% +bigger markets like the tiers four and + + + align:start position:0% +bigger markets like the tiers four and +five of California, Texas, New York. + + align:start position:0% +five of California, Texas, New York. + + + align:start position:0% +five of California, Texas, New York. +These are big markets that have a lot of + + align:start position:0% +These are big markets that have a lot of + + + align:start position:0% +These are big markets that have a lot of +people in them and they have larger + + align:start position:0% +people in them and they have larger + + + align:start position:0% +people in them and they have larger +electricity prices andor large solar + + align:start position:0% +electricity prices andor large solar + + + align:start position:0% +electricity prices andor large solar +resource uh uh available there. And so + + align:start position:0% +resource uh uh available there. And so + + + align:start position:0% +resource uh uh available there. And so +at some point the demand curve reaches + + align:start position:0% +at some point the demand curve reaches + + + align:start position:0% +at some point the demand curve reaches +these plateaus where if you decrease the + + align:start position:0% +these plateaus where if you decrease the + + + align:start position:0% +these plateaus where if you decrease the +price even a little bit all of a sudden + + align:start position:0% +price even a little bit all of a sudden + + + align:start position:0% +price even a little bit all of a sudden +voom the amount of market that you can + + align:start position:0% +voom the amount of market that you can + + + align:start position:0% +voom the amount of market that you can +address right for this amount of of + + align:start position:0% +address right for this amount of of + + + align:start position:0% +address right for this amount of of +price decrease the amount of market that + + align:start position:0% +price decrease the amount of market that + + + align:start position:0% +price decrease the amount of market that +you can address is huge. And so the + + align:start position:0% +you can address is huge. And so the + + + align:start position:0% +you can address is huge. And so the +slope of this line the slope of the + + align:start position:0% +slope of this line the slope of the + + + align:start position:0% +slope of this line the slope of the +demand curve is indicative of what + + align:start position:0% +demand curve is indicative of what + + + align:start position:0% +demand curve is indicative of what +happens when you reduce your price just + + align:start position:0% +happens when you reduce your price just + + + align:start position:0% +happens when you reduce your price just +a little bit. And so yes, producing + + align:start position:0% +a little bit. And so yes, producing + + + align:start position:0% +a little bit. And so yes, producing +cheaper panels when you start hitting + + align:start position:0% +cheaper panels when you start hitting + + + align:start position:0% +cheaper panels when you start hitting +these plateaus can result in massive + + align:start position:0% +these plateaus can result in massive + + + align:start position:0% +these plateaus can result in massive +massive demand pull or market pull. So + + align:start position:0% +massive demand pull or market pull. So + + + align:start position:0% +massive demand pull or market pull. So +that's another good reason to have cheap + + align:start position:0% +that's another good reason to have cheap + + + align:start position:0% +that's another good reason to have cheap +panels. Let's look at the flip side. + + align:start position:0% +panels. Let's look at the flip side. + + + align:start position:0% +panels. Let's look at the flip side. +What would be um what would be some of + + align:start position:0% +What would be um what would be some of + + + align:start position:0% +What would be um what would be some of +the uh downsides let's say uh to uh + + align:start position:0% +the uh downsides let's say uh to uh + + + align:start position:0% +the uh downsides let's say uh to uh +module manufacturing going into China. + + align:start position:0% +module manufacturing going into China. + + + align:start position:0% +module manufacturing going into China. +This you can assume anything is on the + + align:start position:0% +This you can assume anything is on the + + + align:start position:0% +This you can assume anything is on the +table um CO2 emissions, jobs, etc. Let's + + align:start position:0% +table um CO2 emissions, jobs, etc. Let's + + + align:start position:0% +table um CO2 emissions, jobs, etc. Let's +start teasing into some of those + + align:start position:0% +start teasing into some of those + + + align:start position:0% +start teasing into some of those +questions and and looking at some data. + + align:start position:0% +questions and and looking at some data. + + + align:start position:0% +questions and and looking at some data. +I might flip back and forth during the + + align:start position:0% +I might flip back and forth during the + + + align:start position:0% +I might flip back and forth during the +presentation if we have to address + + align:start position:0% +presentation if we have to address + + + align:start position:0% +presentation if we have to address +specific uh topics. So + + align:start position:0% + + + + align:start position:0% + +bad politics if + + align:start position:0% +bad politics if + + + align:start position:0% +bad politics if +American tape manufacturers fail + + align:start position:0% +American tape manufacturers fail + + + align:start position:0% +American tape manufacturers fail +then it reflects poorly on the industry + + align:start position:0% +then it reflects poorly on the industry + + + align:start position:0% +then it reflects poorly on the industry +and American political scene and + + align:start position:0% +and American political scene and + + + align:start position:0% +and American political scene and +decreases support for it. Yep. So um + + align:start position:0% +decreases support for it. Yep. So um + + + align:start position:0% +decreases support for it. Yep. So um +that politics uh in DC uh this is often + + align:start position:0% +that politics uh in DC uh this is often + + + align:start position:0% +that politics uh in DC uh this is often +referred to as the optics of the + + align:start position:0% +referred to as the optics of the + + + align:start position:0% +referred to as the optics of the +situation um how people observe or how + + align:start position:0% +situation um how people observe or how + + + align:start position:0% +situation um how people observe or how +people perceive something. Um the + + align:start position:0% +people perceive something. Um the + + + align:start position:0% +people perceive something. Um the +lititness test is not DC itself. Um I + + align:start position:0% +lititness test is not DC itself. Um I + + + align:start position:0% +lititness test is not DC itself. Um I +was down there on Thursday and everybody + + align:start position:0% +was down there on Thursday and everybody + + + align:start position:0% +was down there on Thursday and everybody +in the solar space was I think it was it + + align:start position:0% +in the solar space was I think it was it + + + align:start position:0% +in the solar space was I think it was it +was Wednesday and Thursday. Yeah. And + + align:start position:0% +was Wednesday and Thursday. Yeah. And + + + align:start position:0% +was Wednesday and Thursday. Yeah. And +everybody in the solar space was + + align:start position:0% +everybody in the solar space was + + + align:start position:0% +everybody in the solar space was +freaking out about uh a particular event + + align:start position:0% +freaking out about uh a particular event + + + align:start position:0% +freaking out about uh a particular event +that was going on in Capitol Hill. I was + + align:start position:0% +that was going on in Capitol Hill. I was + + + align:start position:0% +that was going on in Capitol Hill. I was +telling folks, don't worry. It's not + + align:start position:0% +telling folks, don't worry. It's not + + + align:start position:0% +telling folks, don't worry. It's not +going to I mean in in terms of the rest + + align:start position:0% +going to I mean in in terms of the rest + + + align:start position:0% +going to I mean in in terms of the rest +of the country and the perception of the + + align:start position:0% +of the country and the perception of the + + + align:start position:0% +of the country and the perception of the +rest of the country, it won't be that + + align:start position:0% +rest of the country, it won't be that + + + align:start position:0% +rest of the country, it won't be that +significant. And I'm sure Secretary Chu + + align:start position:0% +significant. And I'm sure Secretary Chu + + + align:start position:0% +significant. And I'm sure Secretary Chu +will do a phenomenal job uh up there in + + align:start position:0% +will do a phenomenal job uh up there in + + + align:start position:0% +will do a phenomenal job uh up there in +in in in front of uh the the + + align:start position:0% +in in in front of uh the the + + + align:start position:0% +in in in front of uh the the +congressional panel. He did phenomenal. + + align:start position:0% +congressional panel. He did phenomenal. + + + align:start position:0% +congressional panel. He did phenomenal. +Um and so people were really really + + align:start position:0% +Um and so people were really really + + + align:start position:0% +Um and so people were really really +worried about something that didn't have + + align:start position:0% +worried about something that didn't have + + + align:start position:0% +worried about something that didn't have +too big of an effect outside. Um granted + + align:start position:0% +too big of an effect outside. Um granted + + + align:start position:0% +too big of an effect outside. Um granted +what people should be worried about is + + align:start position:0% +what people should be worried about is + + + align:start position:0% +what people should be worried about is +the impact for example that this + + align:start position:0% +the impact for example that this + + + align:start position:0% +the impact for example that this +sequestration of discretionary funds + + align:start position:0% +sequestration of discretionary funds + + + align:start position:0% +sequestration of discretionary funds +will have on R&D uh once they start + + align:start position:0% +will have on R&D uh once they start + + + align:start position:0% +will have on R&D uh once they start +kicking in in 2013. Um if you mandate a + + align:start position:0% +kicking in in 2013. Um if you mandate a + + + align:start position:0% +kicking in in 2013. Um if you mandate a +reduced uh funding level for um uh uh + + align:start position:0% +reduced uh funding level for um uh uh + + + align:start position:0% +reduced uh funding level for um uh uh +funding agencies uh you will have an + + align:start position:0% +funding agencies uh you will have an + + + align:start position:0% +funding agencies uh you will have an +impact uh and a long-term one for that + + align:start position:0% +impact uh and a long-term one for that + + + align:start position:0% +impact uh and a long-term one for that +matter. + + align:start position:0% +matter. + + + align:start position:0% +matter. +Um so let's uh let's the optics of the + + align:start position:0% +Um so let's uh let's the optics of the + + + align:start position:0% +Um so let's uh let's the optics of the +situation. Uh there has been a slight + + align:start position:0% +situation. Uh there has been a slight + + + align:start position:0% +situation. Uh there has been a slight +decrease in public support I believe on + + align:start position:0% +decrease in public support I believe on + + + align:start position:0% +decrease in public support I believe on +the order of 5 to 10% um since the + + align:start position:0% +the order of 5 to 10% um since the + + + align:start position:0% +the order of 5 to 10% um since the +beginning of the whole cylinder affair + + align:start position:0% +beginning of the whole cylinder affair + + + align:start position:0% +beginning of the whole cylinder affair +uh support for for solar renewables uh + + align:start position:0% +uh support for for solar renewables uh + + + align:start position:0% +uh support for for solar renewables uh +but the support remains high and still + + align:start position:0% +but the support remains high and still + + + align:start position:0% +but the support remains high and still +continues to be high among uh + + align:start position:0% +continues to be high among uh + + + align:start position:0% +continues to be high among uh +Republicans, Democrats alike. Um + + align:start position:0% +Republicans, Democrats alike. Um + + + align:start position:0% +Republicans, Democrats alike. Um +especially when compared to say + + align:start position:0% +especially when compared to say + + + align:start position:0% +especially when compared to say +congressional approvement uh approval + + align:start position:0% +congressional approvement uh approval + + + align:start position:0% +congressional approvement uh approval +ratings um but let's let's not let's not + + align:start position:0% +ratings um but let's let's not let's not + + + align:start position:0% +ratings um but let's let's not let's not +look look down. Let's compare ourselves + + align:start position:0% +look look down. Let's compare ourselves + + + align:start position:0% +look look down. Let's compare ourselves +to higher. Um what else um what are some + + align:start position:0% +to higher. Um what else um what are some + + + align:start position:0% +to higher. Um what else um what are some +of the potential negatives? Let me let + + align:start position:0% +of the potential negatives? Let me let + + + align:start position:0% +of the potential negatives? Let me let +me start guiding you. Um because there + + align:start position:0% +me start guiding you. Um because there + + + align:start position:0% +me start guiding you. Um because there +you hear so much about bad this jobs + + align:start position:0% +you hear so much about bad this jobs + + + align:start position:0% +you hear so much about bad this jobs +that whatever. Um let me um let me guide + + align:start position:0% +that whatever. Um let me um let me guide + + + align:start position:0% +that whatever. Um let me um let me guide +you into some of the questions that you + + align:start position:0% +you into some of the questions that you + + + align:start position:0% +you into some of the questions that you +might not have thought of. + + align:start position:0% +might not have thought of. + + + align:start position:0% +might not have thought of. +Um there is a colleague of ours in uh + + align:start position:0% +Um there is a colleague of ours in uh + + + align:start position:0% +Um there is a colleague of ours in uh +here at MIT Tim Gatowski's group that is + + align:start position:0% +here at MIT Tim Gatowski's group that is + + + align:start position:0% +here at MIT Tim Gatowski's group that is +looking into matters concerning + + align:start position:0% +looking into matters concerning + + + align:start position:0% +looking into matters concerning +manufacturing of PV and installation of + + align:start position:0% +manufacturing of PV and installation of + + + align:start position:0% +manufacturing of PV and installation of +PV from a CO2 perspective. + + align:start position:0% +PV from a CO2 perspective. + + + align:start position:0% +PV from a CO2 perspective. +So if you manufacture your PV in a + + align:start position:0% +So if you manufacture your PV in a + + + align:start position:0% +So if you manufacture your PV in a +coalrich country that is spewing out + + align:start position:0% +coalrich country that is spewing out + + + align:start position:0% +coalrich country that is spewing out +emissions into the air, um you are going + + align:start position:0% +emissions into the air, um you are going + + + align:start position:0% +emissions into the air, um you are going +to have a greater CO2 intensity per + + align:start position:0% +to have a greater CO2 intensity per + + + align:start position:0% +to have a greater CO2 intensity per +kilowatt hour uh of energy that the + + align:start position:0% +kilowatt hour uh of energy that the + + + align:start position:0% +kilowatt hour uh of energy that the +panels will produce over their lifetime + + align:start position:0% +panels will produce over their lifetime + + + align:start position:0% +panels will produce over their lifetime +than if the panels were produced say in + + align:start position:0% +than if the panels were produced say in + + + align:start position:0% +than if the panels were produced say in +a country that uh fu that has a large + + align:start position:0% +a country that uh fu that has a large + + + align:start position:0% +a country that uh fu that has a large +abundance of hydro power or or uh + + align:start position:0% +abundance of hydro power or or uh + + + align:start position:0% +abundance of hydro power or or uh +geothermal or hey even produces solar + + align:start position:0% +geothermal or hey even produces solar + + + align:start position:0% +geothermal or hey even produces solar +panels using other solar panels. That'd + + align:start position:0% +panels using other solar panels. That'd + + + align:start position:0% +panels using other solar panels. That'd +be nice. Um but in a growth situation + + align:start position:0% +be nice. Um but in a growth situation + + + align:start position:0% +be nice. Um but in a growth situation +where solar is rising or the + + align:start position:0% +where solar is rising or the + + + align:start position:0% +where solar is rising or the +manufacturing capacity is rising at 60% + + align:start position:0% +manufacturing capacity is rising at 60% + + + align:start position:0% +manufacturing capacity is rising at 60% +a year, it's a little bit unfeasible uh + + align:start position:0% +a year, it's a little bit unfeasible uh + + + align:start position:0% +a year, it's a little bit unfeasible uh +to think that solar will power itself + + align:start position:0% +to think that solar will power itself + + + align:start position:0% +to think that solar will power itself +forward. It almost violates one of the + + align:start position:0% +forward. It almost violates one of the + + + align:start position:0% +forward. It almost violates one of the +laws of thermodynamics. Um so we uh we + + align:start position:0% +laws of thermodynamics. Um so we uh we + + + align:start position:0% +laws of thermodynamics. Um so we uh we +look at the CO2 balance, right? Right? + + align:start position:0% +look at the CO2 balance, right? Right? + + + align:start position:0% +look at the CO2 balance, right? Right? +We we think about gee what if um what if + + align:start position:0% +We we think about gee what if um what if + + + align:start position:0% +We we think about gee what if um what if +we were to be smart about where we + + align:start position:0% +we were to be smart about where we + + + align:start position:0% +we were to be smart about where we +manufacture and install + + align:start position:0% +manufacture and install + + + align:start position:0% +manufacture and install +PV then it might make more sense to + + align:start position:0% +PV then it might make more sense to + + + align:start position:0% +PV then it might make more sense to +manufacture PV say in Norway which is + + align:start position:0% +manufacture PV say in Norway which is + + + align:start position:0% +manufacture PV say in Norway which is +based on hydropower and install them in + + align:start position:0% +based on hydropower and install them in + + + align:start position:0% +based on hydropower and install them in +China which is largely running on coal + + align:start position:0% +China which is largely running on coal + + + align:start position:0% +China which is largely running on coal +right so from the CO2 from the global + + align:start position:0% +right so from the CO2 from the global + + + align:start position:0% +right so from the CO2 from the global +carbon perspective um again this these + + align:start position:0% +carbon perspective um again this these + + + align:start position:0% +carbon perspective um again this these +are externalities that aren't being + + align:start position:0% +are externalities that aren't being + + + align:start position:0% +are externalities that aren't being +priced in + + align:start position:0% +priced in + + + align:start position:0% +priced in +okay CO2 and yeah go ahead Please, would + + align:start position:0% +okay CO2 and yeah go ahead Please, would + + + align:start position:0% +okay CO2 and yeah go ahead Please, would +they actually be priced in in Norway + + align:start position:0% +they actually be priced in in Norway + + + align:start position:0% +they actually be priced in in Norway +because they are in the EU emissions + + align:start position:0% +because they are in the EU emissions + + + align:start position:0% +because they are in the EU emissions +trading scheme? I mean, they're not + + align:start position:0% +trading scheme? I mean, they're not + + + align:start position:0% +trading scheme? I mean, they're not +priced in China. Sure. The cost of + + align:start position:0% +priced in China. Sure. The cost of + + + align:start position:0% +priced in China. Sure. The cost of +electricity in Norway doesn't Yeah. So, + + align:start position:0% +electricity in Norway doesn't Yeah. So, + + + align:start position:0% +electricity in Norway doesn't Yeah. So, +so point conceded that in in certain + + align:start position:0% +so point conceded that in in certain + + + align:start position:0% +so point conceded that in in certain +countries, uh, some of the externalities + + align:start position:0% +countries, uh, some of the externalities + + + align:start position:0% +countries, uh, some of the externalities +are factored in, not perhaps at the + + align:start position:0% +are factored in, not perhaps at the + + + align:start position:0% +are factored in, not perhaps at the +levels they should be, but but some are + + align:start position:0% +levels they should be, but but some are + + + align:start position:0% +levels they should be, but but some are +factored in, whereas in other countries + + align:start position:0% +factored in, whereas in other countries + + + align:start position:0% +factored in, whereas in other countries +they're not at all. Um so we have um + + align:start position:0% +they're not at all. Um so we have um + + + align:start position:0% +they're not at all. Um so we have um +what is referred to in some uh in in + + align:start position:0% +what is referred to in some uh in in + + + align:start position:0% +what is referred to in some uh in in +some terms as as an uneven playing field + + align:start position:0% +some terms as as an uneven playing field + + + align:start position:0% +some terms as as an uneven playing field +in the sense that in some places there + + align:start position:0% +in the sense that in some places there + + + align:start position:0% +in the sense that in some places there +are regulations in place that increase + + align:start position:0% +are regulations in place that increase + + + align:start position:0% +are regulations in place that increase +the price of electricity whereas they + + align:start position:0% +the price of electricity whereas they + + + align:start position:0% +the price of electricity whereas they +aren't present in other places and in + + align:start position:0% +aren't present in other places and in + + + align:start position:0% +aren't present in other places and in +some cases they work to your advantage + + align:start position:0% +some cases they work to your advantage + + + align:start position:0% +some cases they work to your advantage +like in Norway for instance or + + align:start position:0% +like in Norway for instance or + + + align:start position:0% +like in Norway for instance or +Switzerland big hydro uh countries. Um + + align:start position:0% +Switzerland big hydro uh countries. Um + + + align:start position:0% +Switzerland big hydro uh countries. Um +what are some other potential + + align:start position:0% +what are some other potential + + + align:start position:0% +what are some other potential +disadvantages? You hear a lot about + + align:start position:0% +disadvantages? You hear a lot about + + + align:start position:0% +disadvantages? You hear a lot about +jobs, right? Jobs moving overseas. Um + + align:start position:0% +jobs, right? Jobs moving overseas. Um + + + align:start position:0% +jobs, right? Jobs moving overseas. Um +let's uh let's start looking at some of + + align:start position:0% +let's uh let's start looking at some of + + + align:start position:0% +let's uh let's start looking at some of +the numbers uh next Thursday when when + + align:start position:0% +the numbers uh next Thursday when when + + + align:start position:0% +the numbers uh next Thursday when when +we have uh Doug coming in here and + + align:start position:0% +we have uh Doug coming in here and + + + align:start position:0% +we have uh Doug coming in here and +talking about the cost model. Um a good + + align:start position:0% +talking about the cost model. Um a good + + + align:start position:0% +talking about the cost model. Um a good +number to keep in mind a good number to + + align:start position:0% +number to keep in mind a good number to + + + align:start position:0% +number to keep in mind a good number to +keep in mind for the manufacturing of + + align:start position:0% +keep in mind for the manufacturing of + + + align:start position:0% +keep in mind for the manufacturing of +modules. Um so back to oopsie back to + + align:start position:0% +modules. Um so back to oopsie back to + + + align:start position:0% +modules. Um so back to oopsie back to +this part right over here. Um for the + + align:start position:0% +this part right over here. Um for the + + + align:start position:0% +this part right over here. Um for the +module itself typical numbers would be + + align:start position:0% +module itself typical numbers would be + + + align:start position:0% +module itself typical numbers would be +two to 12 people depending on what + + align:start position:0% +two to 12 people depending on what + + + align:start position:0% +two to 12 people depending on what +region of the world you're in. two to 12 + + align:start position:0% +region of the world you're in. two to 12 + + + align:start position:0% +region of the world you're in. two to 12 +people per megawatt. So if you have a + + align:start position:0% +people per megawatt. So if you have a + + + align:start position:0% +people per megawatt. So if you have a +total market of say 10 gigawatts, it's + + align:start position:0% +total market of say 10 gigawatts, it's + + + align:start position:0% +total market of say 10 gigawatts, it's +larger than that. We'll do quick math. + + align:start position:0% +larger than that. We'll do quick math. + + + align:start position:0% +larger than that. We'll do quick math. +Um so if it's per megawatt be 20,000 + + align:start position:0% +Um so if it's per megawatt be 20,000 + + + align:start position:0% +Um so if it's per megawatt be 20,000 +people per gig per 10 gigawatts, + + align:start position:0% +people per gig per 10 gigawatts, + + + align:start position:0% +people per gig per 10 gigawatts, +somewhere in that range on the low end + + align:start position:0% +somewhere in that range on the low end + + + align:start position:0% +somewhere in that range on the low end +and on the high end it would be + + align:start position:0% +and on the high end it would be + + + align:start position:0% +and on the high end it would be +somewhere around 200,000 uh people per + + align:start position:0% +somewhere around 200,000 uh people per + + + align:start position:0% +somewhere around 200,000 uh people per +gigawatt on the high end of the labor + + align:start position:0% +gigawatt on the high end of the labor + + + align:start position:0% +gigawatt on the high end of the labor +intensity. So the high end of the labor + + align:start position:0% +intensity. So the high end of the labor + + + align:start position:0% +intensity. So the high end of the labor +intensity represents a company like + + align:start position:0% +intensity represents a company like + + + align:start position:0% +intensity represents a company like +Trina Solar in in China that is + + align:start position:0% +Trina Solar in in China that is + + + align:start position:0% +Trina Solar in in China that is +extremely labor intensive. It's located + + align:start position:0% +extremely labor intensive. It's located + + + align:start position:0% +extremely labor intensive. It's located +in in Changhu. It's on the highspeed + + align:start position:0% +in in Changhu. It's on the highspeed + + + align:start position:0% +in in Changhu. It's on the highspeed +rail between uh Shanghai and and and + + align:start position:0% +rail between uh Shanghai and and and + + + align:start position:0% +rail between uh Shanghai and and and +Nanqing. Um the low end of that scale + + align:start position:0% +Nanqing. Um the low end of that scale + + + align:start position:0% +Nanqing. Um the low end of that scale +would be more representative of say + + align:start position:0% +would be more representative of say + + + align:start position:0% +would be more representative of say +SUNTC which is almost next door in Wooi. + + align:start position:0% +SUNTC which is almost next door in Wooi. + + + align:start position:0% +SUNTC which is almost next door in Wooi. +um which has adopted a different + + align:start position:0% +um which has adopted a different + + + align:start position:0% +um which has adopted a different +approach saying we're going to invest in + + align:start position:0% +approach saying we're going to invest in + + + align:start position:0% +approach saying we're going to invest in +robots because we're uncertain about + + align:start position:0% +robots because we're uncertain about + + + align:start position:0% +robots because we're uncertain about +where the whole labor thing is going to + + align:start position:0% +where the whole labor thing is going to + + + align:start position:0% +where the whole labor thing is going to +go in China where the prices are going + + align:start position:0% +go in China where the prices are going + + + align:start position:0% +go in China where the prices are going +to go or RECC in uh which is a Norwegian + + align:start position:0% +to go or RECC in uh which is a Norwegian + + + align:start position:0% +to go or RECC in uh which is a Norwegian +company but they opened a factory in + + align:start position:0% +company but they opened a factory in + + + align:start position:0% +company but they opened a factory in +Singapore which has very very low uh + + align:start position:0% +Singapore which has very very low uh + + + align:start position:0% +Singapore which has very very low uh +labor uh rates because they invested a + + align:start position:0% +labor uh rates because they invested a + + + align:start position:0% +labor uh rates because they invested a +lot of money in capital equipment in + + align:start position:0% +lot of money in capital equipment in + + + align:start position:0% +lot of money in capital equipment in +robots to move modules around their + + align:start position:0% +robots to move modules around their + + + align:start position:0% +robots to move modules around their +factories. Um US if you can look at + + align:start position:0% +factories. Um US if you can look at + + + align:start position:0% +factories. Um US if you can look at +turnkey manufacturing lines are + + align:start position:0% +turnkey manufacturing lines are + + + align:start position:0% +turnkey manufacturing lines are +typically around 3 3.5 people per + + align:start position:0% +typically around 3 3.5 people per + + + align:start position:0% +typically around 3 3.5 people per +megawatt. Uh those are some good numbers + + align:start position:0% +megawatt. Uh those are some good numbers + + + align:start position:0% +megawatt. Uh those are some good numbers +to keep in mind. So when anybody comes + + align:start position:0% +to keep in mind. So when anybody comes + + + align:start position:0% +to keep in mind. So when anybody comes +to you and says jobs, solar jobs, um + + align:start position:0% +to you and says jobs, solar jobs, um + + + align:start position:0% +to you and says jobs, solar jobs, um +with these sorts of numbers, you can + + align:start position:0% +with these sorts of numbers, you can + + + align:start position:0% +with these sorts of numbers, you can +begin estimating. Okay, let give me a + + align:start position:0% +begin estimating. Okay, let give me a + + + align:start position:0% +begin estimating. Okay, let give me a +number. How big is the solar market + + align:start position:0% +number. How big is the solar market + + + align:start position:0% +number. How big is the solar market +going to grow to? Um what is the level + + align:start position:0% +going to grow to? Um what is the level + + + align:start position:0% +going to grow to? Um what is the level +of automation? What is the labor + + align:start position:0% +of automation? What is the labor + + + align:start position:0% +of automation? What is the labor +intensity of manu manufacturing of the + + align:start position:0% +intensity of manu manufacturing of the + + + align:start position:0% +intensity of manu manufacturing of the +modules? And you can make an estimate on + + align:start position:0% +modules? And you can make an estimate on + + + align:start position:0% +modules? And you can make an estimate on +the total number of jobs, direct jobs, + + align:start position:0% +the total number of jobs, direct jobs, + + + align:start position:0% +the total number of jobs, direct jobs, +direct jobs associated with the module + + align:start position:0% +direct jobs associated with the module + + + align:start position:0% +direct jobs associated with the module +manufacturing. Then there are all the + + align:start position:0% +manufacturing. Then there are all the + + + align:start position:0% +manufacturing. Then there are all the +indirect jobs as well, right? They're + + align:start position:0% +indirect jobs as well, right? They're + + + align:start position:0% +indirect jobs as well, right? They're +all the people supplying the commodity + + align:start position:0% +all the people supplying the commodity + + + align:start position:0% +all the people supplying the commodity +materials into your manufacturing line. + + align:start position:0% +materials into your manufacturing line. + + + align:start position:0% +materials into your manufacturing line. +they're all the people um who are + + align:start position:0% +they're all the people um who are + + + align:start position:0% +they're all the people um who are +working as as administrative assistants + + align:start position:0% +working as as administrative assistants + + + align:start position:0% +working as as administrative assistants +and and R&D staff and so forth. So, uh + + align:start position:0% +and and R&D staff and so forth. So, uh + + + align:start position:0% +and and R&D staff and so forth. So, uh +it's not quite as simple as that, but it + + align:start position:0% +it's not quite as simple as that, but it + + + align:start position:0% +it's not quite as simple as that, but it +gives you a number to really start + + align:start position:0% +gives you a number to really start + + + align:start position:0% +gives you a number to really start +grabbing. Um and that of course doesn't + + align:start position:0% +grabbing. Um and that of course doesn't + + + align:start position:0% +grabbing. Um and that of course doesn't +include all the installations, installer + + align:start position:0% +include all the installations, installer + + + align:start position:0% +include all the installations, installer +jobs, + + align:start position:0% +jobs, + + + align:start position:0% +jobs, +I All right. So, when we're talking + + align:start position:0% +I All right. So, when we're talking + + + align:start position:0% +I All right. So, when we're talking +about grid tide electricity, um I'd like + + align:start position:0% +about grid tide electricity, um I'd like + + + align:start position:0% +about grid tide electricity, um I'd like +to move on to our next few um next few + + align:start position:0% +to move on to our next few um next few + + + align:start position:0% +to move on to our next few um next few +topics here. When we're talking about + + align:start position:0% +topics here. When we're talking about + + + align:start position:0% +topics here. When we're talking about +grid tide electricity, um this is in + + align:start position:0% +grid tide electricity, um this is in + + + align:start position:0% +grid tide electricity, um this is in +German. Sorry about that. Um this is + + align:start position:0% +German. Sorry about that. Um this is + + + align:start position:0% +German. Sorry about that. Um this is +over a period uh v means day of the + + align:start position:0% +over a period uh v means day of the + + + align:start position:0% +over a period uh v means day of the +week. Um and this is basically the uh + + align:start position:0% +week. Um and this is basically the uh + + + align:start position:0% +week. Um and this is basically the uh +the peak um uh power uh in gigawatts uh + + align:start position:0% +the peak um uh power uh in gigawatts uh + + + align:start position:0% +the peak um uh power uh in gigawatts uh +instantaneous at at any given point. So + + align:start position:0% +instantaneous at at any given point. So + + + align:start position:0% +instantaneous at at any given point. So +we have you know morning middle of the + + align:start position:0% +we have you know morning middle of the + + + align:start position:0% +we have you know morning middle of the +day night middle of the day night + + align:start position:0% +day night middle of the day night + + + align:start position:0% +day night middle of the day night +there's a little bump right here during + + align:start position:0% +there's a little bump right here during + + + align:start position:0% +there's a little bump right here during +prime time TV. Um and we have the uh + + align:start position:0% +prime time TV. Um and we have the uh + + + align:start position:0% +prime time TV. Um and we have the uh +output of PV um going from 5 gawatt peak + + align:start position:0% +output of PV um going from 5 gawatt peak + + + align:start position:0% +output of PV um going from 5 gawatt peak +to 30 gawatt peak. you can see uh + + align:start position:0% +to 30 gawatt peak. you can see uh + + + align:start position:0% +to 30 gawatt peak. you can see uh +beginning to eat into uh the profits + + align:start position:0% +beginning to eat into uh the profits + + + align:start position:0% +beginning to eat into uh the profits +essentially the uh peak hours um right + + align:start position:0% +essentially the uh peak hours um right + + + align:start position:0% +essentially the uh peak hours um right +so let me let me differentiate between + + align:start position:0% +so let me let me differentiate between + + + align:start position:0% +so let me let me differentiate between +base load and peak base load power would + + align:start position:0% +base load and peak base load power would + + + align:start position:0% +base load and peak base load power would +be voom right something uh providing a + + align:start position:0% +be voom right something uh providing a + + + align:start position:0% +be voom right something uh providing a +constant power output uh as a function + + align:start position:0% +constant power output uh as a function + + + align:start position:0% +constant power output uh as a function +of time something like a nuclear power + + align:start position:0% +of time something like a nuclear power + + + align:start position:0% +of time something like a nuclear power +plant coal fired power plant peakers + + align:start position:0% +plant coal fired power plant peakers + + + align:start position:0% +plant coal fired power plant peakers +would be natural gas fired power plants + + align:start position:0% +would be natural gas fired power plants + + + align:start position:0% +would be natural gas fired power plants +that receive the calls like Jessica + + align:start position:0% +that receive the calls like Jessica + + + align:start position:0% +that receive the calls like Jessica +you're in charge of the peaker over + + align:start position:0% +you're in charge of the peaker over + + + align:start position:0% +you're in charge of the peaker over +there based on my weather report today + + align:start position:0% +there based on my weather report today + + + align:start position:0% +there based on my weather report today +I'm going to need so many gigawatts + + align:start position:0% +I'm going to need so many gigawatts + + + align:start position:0% +I'm going to need so many gigawatts +tomorrow between the hours of 10 and 12 + + align:start position:0% +tomorrow between the hours of 10 and 12 + + + align:start position:0% +tomorrow between the hours of 10 and 12 +you think you can turn yourself on then + + align:start position:0% +you think you can turn yourself on then + + + align:start position:0% +you think you can turn yourself on then +I'll pay you this amount of yep + + align:start position:0% +I'll pay you this amount of yep + + + align:start position:0% +I'll pay you this amount of yep +Jessica's going to battle sheet yes I + + align:start position:0% +Jessica's going to battle sheet yes I + + + align:start position:0% +Jessica's going to battle sheet yes I +can do that PV on the other hand is + + align:start position:0% +can do that PV on the other hand is + + + align:start position:0% +can do that PV on the other hand is +coming on if the sun's coming on right + + align:start position:0% +coming on if the sun's coming on right + + + align:start position:0% +coming on if the sun's coming on right +and today there isn't a great degree of + + align:start position:0% +and today there isn't a great degree of + + + align:start position:0% +and today there isn't a great degree of +predictability we can see if that's + + align:start position:0% +predictability we can see if that's + + + align:start position:0% +predictability we can see if that's +going to change based on one of our + + align:start position:0% +going to change based on one of our + + + align:start position:0% +going to change based on one of our +class projects here but there wasn't a + + align:start position:0% +class projects here but there wasn't a + + + align:start position:0% +class projects here but there wasn't a +great degree of predictability you can + + align:start position:0% +great degree of predictability you can + + + align:start position:0% +great degree of predictability you can +see here for example um and here varying + + align:start position:0% +see here for example um and here varying + + + align:start position:0% +see here for example um and here varying +amounts of sunlight from one day to the + + align:start position:0% +amounts of sunlight from one day to the + + + align:start position:0% +amounts of sunlight from one day to the +other uh as a result of changing um + + align:start position:0% +other uh as a result of changing um + + + align:start position:0% +other uh as a result of changing um +insulation uh there's of course changing + + align:start position:0% +insulation uh there's of course changing + + + align:start position:0% +insulation uh there's of course changing +demand as a day of the week goes by on + + align:start position:0% +demand as a day of the week goes by on + + + align:start position:0% +demand as a day of the week goes by on +Saturday and Sunday there's less demand + + align:start position:0% +Saturday and Sunday there's less demand + + + align:start position:0% +Saturday and Sunday there's less demand +for electricity + + align:start position:0% +for electricity + + + align:start position:0% +for electricity +So what PV is doing is eating into some + + align:start position:0% +So what PV is doing is eating into some + + + align:start position:0% +So what PV is doing is eating into some +of the highest use periods which is good + + align:start position:0% +of the highest use periods which is good + + + align:start position:0% +of the highest use periods which is good +from the markets perspect from the um uh + + align:start position:0% +from the markets perspect from the um uh + + + align:start position:0% +from the markets perspect from the um uh +shall we say the uh person in charge of + + align:start position:0% +shall we say the uh person in charge of + + + align:start position:0% +shall we say the uh person in charge of +maintaining grid stabilities perspective + + align:start position:0% +maintaining grid stabilities perspective + + + align:start position:0% +maintaining grid stabilities perspective +because they want uh uh power to be + + align:start position:0% +because they want uh uh power to be + + + align:start position:0% +because they want uh uh power to be +produced then they don't want to run out + + align:start position:0% +produced then they don't want to run out + + + align:start position:0% +produced then they don't want to run out +of generation capacity. NPV is avoiding + + align:start position:0% +of generation capacity. NPV is avoiding + + + align:start position:0% +of generation capacity. NPV is avoiding +the situation or at least prolonging the + + align:start position:0% +the situation or at least prolonging the + + + align:start position:0% +the situation or at least prolonging the +situation a few more years until we run + + align:start position:0% +situation a few more years until we run + + + align:start position:0% +situation a few more years until we run +out of power generation capacity on the + + align:start position:0% +out of power generation capacity on the + + + align:start position:0% +out of power generation capacity on the +grid. + + align:start position:0% +grid. + + + align:start position:0% +grid. +um as our population grows and our + + align:start position:0% +um as our population grows and our + + + align:start position:0% +um as our population grows and our +energy intensity grows, we're needing + + align:start position:0% +energy intensity grows, we're needing + + + align:start position:0% +energy intensity grows, we're needing +more and more power, but we're not + + align:start position:0% +more and more power, but we're not + + + align:start position:0% +more and more power, but we're not +building new power plants at that rate, + + align:start position:0% +building new power plants at that rate, + + + align:start position:0% +building new power plants at that rate, +right? Generally in Germany and the + + align:start position:0% +right? Generally in Germany and the + + + align:start position:0% +right? Generally in Germany and the +United States. Um and so PV is helping + + align:start position:0% +United States. Um and so PV is helping + + + align:start position:0% +United States. Um and so PV is helping +to defay some of that deferred + + align:start position:0% +to defay some of that deferred + + + align:start position:0% +to defay some of that deferred +investment in new generation capacity. + + align:start position:0% +investment in new generation capacity. + + + align:start position:0% +investment in new generation capacity. +So that's good. On the bad side, + + align:start position:0% +So that's good. On the bad side, + + + align:start position:0% +So that's good. On the bad side, +somebody who's invested, let's say, um + + align:start position:0% +somebody who's invested, let's say, um + + + align:start position:0% +somebody who's invested, let's say, um +let's say Mary has invested in a a + + align:start position:0% +let's say Mary has invested in a a + + + align:start position:0% +let's say Mary has invested in a a +natural gas generation plant, um she put + + align:start position:0% +natural gas generation plant, um she put + + + align:start position:0% +natural gas generation plant, um she put +the money down for Jessica's plant. + + align:start position:0% +the money down for Jessica's plant. + + + align:start position:0% +the money down for Jessica's plant. +Jessica's running it. And uh and and now + + align:start position:0% +Jessica's running it. And uh and and now + + + align:start position:0% +Jessica's running it. And uh and and now +Mary realizes, well, goodness. Um I + + align:start position:0% +Mary realizes, well, goodness. Um I + + + align:start position:0% +Mary realizes, well, goodness. Um I +thought I was going to get a steady rate + + align:start position:0% +thought I was going to get a steady rate + + + align:start position:0% +thought I was going to get a steady rate +of return over 20 years for my natural + + align:start position:0% +of return over 20 years for my natural + + + align:start position:0% +of return over 20 years for my natural +gas firepower plant. That that rate of + + align:start position:0% +gas firepower plant. That that rate of + + + align:start position:0% +gas firepower plant. That that rate of +return was factored into my economic + + align:start position:0% +return was factored into my economic + + + align:start position:0% +return was factored into my economic +analysis when I borrowed money at a + + align:start position:0% +analysis when I borrowed money at a + + + align:start position:0% +analysis when I borrowed money at a +certain rate from a bank. And now you're + + align:start position:0% +certain rate from a bank. And now you're + + + align:start position:0% +certain rate from a bank. And now you're +telling me that this upstart technology, + + align:start position:0% +telling me that this upstart technology, + + + align:start position:0% +telling me that this upstart technology, +this new PV stuff is coming online and + + align:start position:0% +this new PV stuff is coming online and + + + align:start position:0% +this new PV stuff is coming online and +is going to take away some of my profit. + + align:start position:0% +is going to take away some of my profit. + + + align:start position:0% +is going to take away some of my profit. +That that's that that doesn't work for + + align:start position:0% +That that's that that doesn't work for + + + align:start position:0% +That that's that that doesn't work for +me. Um, as a matter of fact, um, on peak + + align:start position:0% +me. Um, as a matter of fact, um, on peak + + + align:start position:0% +me. Um, as a matter of fact, um, on peak +days in Bavaria, which is the + + align:start position:0% +days in Bavaria, which is the + + + align:start position:0% +days in Bavaria, which is the +southeastern part of Germany today, uh, + + align:start position:0% +southeastern part of Germany today, uh, + + + align:start position:0% +southeastern part of Germany today, uh, +PV can comprise as much as 40% of + + align:start position:0% +PV can comprise as much as 40% of + + + align:start position:0% +PV can comprise as much as 40% of +electricity on the grid, uh, during peak + + align:start position:0% +electricity on the grid, uh, during peak + + + align:start position:0% +electricity on the grid, uh, during peak +hours during the summer. And, and what + + align:start position:0% +hours during the summer. And, and what + + + align:start position:0% +hours during the summer. And, and what +that does sometimes is force + + align:start position:0% +that does sometimes is force + + + align:start position:0% +that does sometimes is force +conventional uh, uh, electricity + + align:start position:0% +conventional uh, uh, electricity + + + align:start position:0% +conventional uh, uh, electricity +producers to either turn off or going + + align:start position:0% +producers to either turn off or going + + + align:start position:0% +producers to either turn off or going +into negative pricing, meaning they + + align:start position:0% +into negative pricing, meaning they + + + align:start position:0% +into negative pricing, meaning they +shunt the power to ground so that they + + align:start position:0% +shunt the power to ground so that they + + + align:start position:0% +shunt the power to ground so that they +don't have to pay to put their + + align:start position:0% +don't have to pay to put their + + + align:start position:0% +don't have to pay to put their +electricity on the grid. So that's uh an + + align:start position:0% +electricity on the grid. So that's uh an + + + align:start position:0% +electricity on the grid. So that's uh an +interesting market dynamic that's + + align:start position:0% +interesting market dynamic that's + + + align:start position:0% +interesting market dynamic that's +evolving as more and more PV electricity + + align:start position:0% +evolving as more and more PV electricity + + + align:start position:0% +evolving as more and more PV electricity +enters the grid uh in these regions um + + align:start position:0% +enters the grid uh in these regions um + + + align:start position:0% +enters the grid uh in these regions um +of high penetration which include uh + + align:start position:0% +of high penetration which include uh + + + align:start position:0% +of high penetration which include uh +California, Hawaii uh the island of Lai + + align:start position:0% +California, Hawaii uh the island of Lai + + + align:start position:0% +California, Hawaii uh the island of Lai +I believe has um up to 40% as well on on + + align:start position:0% +I believe has um up to 40% as well on on + + + align:start position:0% +I believe has um up to 40% as well on on +peak days. Um Bavaria and Germany which + + align:start position:0% +peak days. Um Bavaria and Germany which + + + align:start position:0% +peak days. Um Bavaria and Germany which +is the southeastern part of Germany. Um + + align:start position:0% +is the southeastern part of Germany. Um + + + align:start position:0% +is the southeastern part of Germany. Um +let me um try get to this point right + + align:start position:0% +let me um try get to this point right + + + align:start position:0% +let me um try get to this point right +here is predicting where the market will + + align:start position:0% +here is predicting where the market will + + + align:start position:0% +here is predicting where the market will +go. We talked about the demand curve for + + align:start position:0% +go. We talked about the demand curve for + + + align:start position:0% +go. We talked about the demand curve for +PV and we collapsed um we collapsed both + + align:start position:0% +PV and we collapsed um we collapsed both + + + align:start position:0% +PV and we collapsed um we collapsed both +insulation and price of electricity from + + align:start position:0% +insulation and price of electricity from + + + align:start position:0% +insulation and price of electricity from +the grid into this dollars per watt peak + + align:start position:0% +the grid into this dollars per watt peak + + + align:start position:0% +the grid into this dollars per watt peak +figure which is how much people are + + align:start position:0% +figure which is how much people are + + + align:start position:0% +figure which is how much people are +willing to pay. We can also break it out + + align:start position:0% +willing to pay. We can also break it out + + + align:start position:0% +willing to pay. We can also break it out +into annual solar energy yield. This is + + align:start position:0% +into annual solar energy yield. This is + + + align:start position:0% +into annual solar energy yield. This is +the solar resource available. Um it's + + align:start position:0% +the solar resource available. Um it's + + + align:start position:0% +the solar resource available. Um it's +used it's using the uh units of kilowatt + + align:start position:0% +used it's using the uh units of kilowatt + + + align:start position:0% +used it's using the uh units of kilowatt +hours per kilowatt peak meaning the + + align:start position:0% +hours per kilowatt peak meaning the + + + align:start position:0% +hours per kilowatt peak meaning the +number of kilowatt hours the amount of + + align:start position:0% +number of kilowatt hours the amount of + + + align:start position:0% +number of kilowatt hours the amount of +energy that a unit of rated power + + align:start position:0% +energy that a unit of rated power + + + align:start position:0% +energy that a unit of rated power +kilowatt peak of the solar panel is + + align:start position:0% +kilowatt peak of the solar panel is + + + align:start position:0% +kilowatt peak of the solar panel is +going to produce. So, how much energy + + align:start position:0% +going to produce. So, how much energy + + + align:start position:0% +going to produce. So, how much energy +will a unit of solar panel produce? + + align:start position:0% +will a unit of solar panel produce? + + + align:start position:0% +will a unit of solar panel produce? +That's down here. And of course, larger + + align:start position:0% +That's down here. And of course, larger + + + align:start position:0% +That's down here. And of course, larger +amounts mean more sun, more solar + + align:start position:0% +amounts mean more sun, more solar + + + align:start position:0% +amounts mean more sun, more solar +resource. On the uh on the ordinate, we + + align:start position:0% +resource. On the uh on the ordinate, we + + + align:start position:0% +resource. On the uh on the ordinate, we +have average power price of household. + + align:start position:0% +have average power price of household. + + + align:start position:0% +have average power price of household. +This is um US dollars. It should be uh + + align:start position:0% +This is um US dollars. It should be uh + + + align:start position:0% +This is um US dollars. It should be uh +average electricity price, US dollars + + align:start position:0% +average electricity price, US dollars + + + align:start position:0% +average electricity price, US dollars +per kilowatt hour. Um so, that's how + + align:start position:0% +per kilowatt hour. Um so, that's how + + + align:start position:0% +per kilowatt hour. Um so, that's how +much people are paying for their + + align:start position:0% +much people are paying for their + + + align:start position:0% +much people are paying for their +electricity, what you're displacing. And + + align:start position:0% +electricity, what you're displacing. And + + + align:start position:0% +electricity, what you're displacing. And +you can see that these little bubbles + + align:start position:0% +you can see that these little bubbles + + + align:start position:0% +you can see that these little bubbles +here represent the size of the market. + + align:start position:0% +here represent the size of the market. + + + align:start position:0% +here represent the size of the market. +So as the price of PV electricity comes + + align:start position:0% +So as the price of PV electricity comes + + + align:start position:0% +So as the price of PV electricity comes +down, we are able to address more and + + align:start position:0% +down, we are able to address more and + + + align:start position:0% +down, we are able to address more and +more markets. As the subsidization of PV + + align:start position:0% +more markets. As the subsidization of PV + + + align:start position:0% +more markets. As the subsidization of PV +electricity increases, you move these + + align:start position:0% +electricity increases, you move these + + + align:start position:0% +electricity increases, you move these +little bubbles up. And as the + + align:start position:0% +little bubbles up. And as the + + + align:start position:0% +little bubbles up. And as the +subsidiation comes back down, the market + + align:start position:0% +subsidiation comes back down, the market + + + align:start position:0% +subsidiation comes back down, the market +pull, not not the manufacturing + + align:start position:0% +pull, not not the manufacturing + + + align:start position:0% +pull, not not the manufacturing +subsidies, but the uh the uh use or + + align:start position:0% +subsidies, but the uh the uh use or + + + align:start position:0% +subsidies, but the uh the uh use or +installation subsidies as they come back + + align:start position:0% +installation subsidies as they come back + + + align:start position:0% +installation subsidies as they come back +down, the little bubbles move down um + + align:start position:0% +down, the little bubbles move down um + + + align:start position:0% +down, the little bubbles move down um +and eventually rest at their their their + + align:start position:0% +and eventually rest at their their their + + + align:start position:0% +and eventually rest at their their their +uh so-called true market price without + + align:start position:0% +uh so-called true market price without + + + align:start position:0% +uh so-called true market price without +the externalities factored in. And so + + align:start position:0% +the externalities factored in. And so + + + align:start position:0% +the externalities factored in. And so +you can see how we're beginning to enter + + align:start position:0% +you can see how we're beginning to enter + + + align:start position:0% +you can see how we're beginning to enter +uh a regime where PV is starting to look + + align:start position:0% +uh a regime where PV is starting to look + + + align:start position:0% +uh a regime where PV is starting to look +interesting in a lot of places. And as + + align:start position:0% +interesting in a lot of places. And as + + + align:start position:0% +interesting in a lot of places. And as +we begin addressing these markets or + + align:start position:0% +we begin addressing these markets or + + + align:start position:0% +we begin addressing these markets or +hitting these markets, you can imagine + + align:start position:0% +hitting these markets, you can imagine + + + align:start position:0% +hitting these markets, you can imagine +two Gaussian curves intersecting. one + + align:start position:0% +two Gaussian curves intersecting. one + + + align:start position:0% +two Gaussian curves intersecting. one +being the price of PV electricity, other + + align:start position:0% +being the price of PV electricity, other + + + align:start position:0% +being the price of PV electricity, other +being the price of grid electricity. As + + align:start position:0% +being the price of grid electricity. As + + + align:start position:0% +being the price of grid electricity. As +they oversight and overlap, you expect + + align:start position:0% +they oversight and overlap, you expect + + + align:start position:0% +they oversight and overlap, you expect +an exponential growth and that's what + + align:start position:0% +an exponential growth and that's what + + + align:start position:0% +an exponential growth and that's what +we're seeing in the market today. + + align:start position:0% +we're seeing in the market today. + + + align:start position:0% +we're seeing in the market today. +Question, what is the principle for tier + + align:start position:0% +Question, what is the principle for tier + + + align:start position:0% +Question, what is the principle for tier +four? Yeah. So, California decided to + + align:start position:0% +four? Yeah. So, California decided to + + + align:start position:0% +four? Yeah. So, California decided to +implement um more of a instead of um + + align:start position:0% +implement um more of a instead of um + + + align:start position:0% +implement um more of a instead of um +well, it is uh a little bit um + + align:start position:0% +well, it is uh a little bit um + + + align:start position:0% +well, it is uh a little bit um +regressive in that sense, but it what + + align:start position:0% +regressive in that sense, but it what + + + align:start position:0% +regressive in that sense, but it what +they did is they said let's instead of + + align:start position:0% +they did is they said let's instead of + + + align:start position:0% +they did is they said let's instead of +um instead of paying the same price per + + align:start position:0% +um instead of paying the same price per + + + align:start position:0% +um instead of paying the same price per +electricity, everybody um which actually + + align:start position:0% +electricity, everybody um which actually + + + align:start position:0% +electricity, everybody um which actually +it would be even the opposite way. Um + + align:start position:0% +it would be even the opposite way. Um + + + align:start position:0% +it would be even the opposite way. Um +you know how residential we typically + + align:start position:0% +you know how residential we typically + + + align:start position:0% +you know how residential we typically +pay higher rates in industrial that's + + align:start position:0% +pay higher rates in industrial that's + + + align:start position:0% +pay higher rates in industrial that's +because industrial buys in bulk. They + + align:start position:0% +because industrial buys in bulk. They + + + align:start position:0% +because industrial buys in bulk. They +buy electricity Costco size. we just buy + + align:start position:0% +buy electricity Costco size. we just buy + + + align:start position:0% +buy electricity Costco size. we just buy +it, you know, corner store size and so + + align:start position:0% +it, you know, corner store size and so + + + align:start position:0% +it, you know, corner store size and so +they pay less for the electricity. And + + align:start position:0% +they pay less for the electricity. And + + + align:start position:0% +they pay less for the electricity. And +in California realized this and said, + + align:start position:0% +in California realized this and said, + + + align:start position:0% +in California realized this and said, +well, this is a perverse incentive. What + + align:start position:0% +well, this is a perverse incentive. What + + + align:start position:0% +well, this is a perverse incentive. What +this does is it gives an incentive to + + align:start position:0% +this does is it gives an incentive to + + + align:start position:0% +this does is it gives an incentive to +people to use more electricity because + + align:start position:0% +people to use more electricity because + + + align:start position:0% +people to use more electricity because +if you buy in Costco size, you pay less + + align:start position:0% +if you buy in Costco size, you pay less + + + align:start position:0% +if you buy in Costco size, you pay less +per kilowatt hour than if you buy in the + + align:start position:0% +per kilowatt hour than if you buy in the + + + align:start position:0% +per kilowatt hour than if you buy in the +corner store. Um, instead what we're + + align:start position:0% +corner store. Um, instead what we're + + + align:start position:0% +corner store. Um, instead what we're +going to do is reverse that incentive by + + align:start position:0% +going to do is reverse that incentive by + + + align:start position:0% +going to do is reverse that incentive by +penalizing the people who buy more + + align:start position:0% +penalizing the people who buy more + + + align:start position:0% +penalizing the people who buy more +electricity. So your rate is going to be + + align:start position:0% +electricity. So your rate is going to be + + + align:start position:0% +electricity. So your rate is going to be +higher than if you just bought a small + + align:start position:0% +higher than if you just bought a small + + + align:start position:0% +higher than if you just bought a small +uh amount. So what they did is the + + align:start position:0% +uh amount. So what they did is the + + + align:start position:0% +uh amount. So what they did is the +government bureaucrats got together with + + align:start position:0% +government bureaucrats got together with + + + align:start position:0% +government bureaucrats got together with +some of the scholars and decided these + + align:start position:0% +some of the scholars and decided these + + + align:start position:0% +some of the scholars and decided these +are reasonable amounts for a residential + + align:start position:0% +are reasonable amounts for a residential + + + align:start position:0% +are reasonable amounts for a residential +house to consume. Um this is the next + + align:start position:0% +house to consume. Um this is the next + + + align:start position:0% +house to consume. Um this is the next +tier up. This is the next tier up. This + + align:start position:0% +tier up. This is the next tier up. This + + + align:start position:0% +tier up. This is the next tier up. This +is the next tier up and this is + + align:start position:0% +is the next tier up and this is + + + align:start position:0% +is the next tier up and this is +completely unreasonable. Um and so uh + + align:start position:0% +completely unreasonable. Um and so uh + + + align:start position:0% +completely unreasonable. Um and so uh +what they did is they tiered their + + align:start position:0% +what they did is they tiered their + + + align:start position:0% +what they did is they tiered their +electricity and you have California tier + + align:start position:0% +electricity and you have California tier + + + align:start position:0% +electricity and you have California tier +uh tiers one, two, and three represented + + align:start position:0% +uh tiers one, two, and three represented + + + align:start position:0% +uh tiers one, two, and three represented +by the big bubble and tier four and tier + + align:start position:0% +by the big bubble and tier four and tier + + + align:start position:0% +by the big bubble and tier four and tier +five um as represented at higher + + align:start position:0% +five um as represented at higher + + + align:start position:0% +five um as represented at higher +pricing. So, if you happen to fall into + + align:start position:0% +pricing. So, if you happen to fall into + + + align:start position:0% +pricing. So, if you happen to fall into +the tier five category, you could be + + align:start position:0% +the tier five category, you could be + + + align:start position:0% +the tier five category, you could be +paying upward of 30 cents per kilowatt + + align:start position:0% +paying upward of 30 cents per kilowatt + + + align:start position:0% +paying upward of 30 cents per kilowatt +hour uh for your your electricity. And + + align:start position:0% +hour uh for your your electricity. And + + + align:start position:0% +hour uh for your your electricity. And +it's a way of penalizing you for + + align:start position:0% +it's a way of penalizing you for + + + align:start position:0% +it's a way of penalizing you for +powering u two swimming pools in your + + align:start position:0% +powering u two swimming pools in your + + + align:start position:0% +powering u two swimming pools in your +backyard um along with uh I don't know + + align:start position:0% +backyard um along with uh I don't know + + + align:start position:0% +backyard um along with uh I don't know +something in the range of of 10 + + align:start position:0% +something in the range of of 10 + + + align:start position:0% +something in the range of of 10 +kilowatts of of lighting inside of your + + align:start position:0% +kilowatts of of lighting inside of your + + + align:start position:0% +kilowatts of of lighting inside of your +house. Um whereas if if you're running + + align:start position:0% +house. Um whereas if if you're running + + + align:start position:0% +house. Um whereas if if you're running +on a meager budget, um you might do much + + align:start position:0% +on a meager budget, um you might do much + + + align:start position:0% +on a meager budget, um you might do much +better. Do we have a question over here? + + align:start position:0% +better. Do we have a question over here? + + + align:start position:0% +better. Do we have a question over here? +No. Is it all residential? Um the + + align:start position:0% +No. Is it all residential? Um the + + + align:start position:0% +No. Is it all residential? Um the +California's tier one, two, three, and + + align:start position:0% +California's tier one, two, three, and + + + align:start position:0% +California's tier one, two, three, and +four, and five. That's a great question. + + align:start position:0% +four, and five. That's a great question. + + + align:start position:0% +four, and five. That's a great question. +Um Joe, would you happen to know if if + + align:start position:0% +Um Joe, would you happen to know if if + + + align:start position:0% +Um Joe, would you happen to know if if +if commercial and industrial fall into + + align:start position:0% +if commercial and industrial fall into + + + align:start position:0% +if commercial and industrial fall into +tiers as well or if it's just res? No, + + align:start position:0% +tiers as well or if it's just res? No, + + + align:start position:0% +tiers as well or if it's just res? No, +because that'd be political suicide. + + align:start position:0% +because that'd be political suicide. + + + align:start position:0% +because that'd be political suicide. +Well, even the residential is political + + align:start position:0% +Well, even the residential is political + + + align:start position:0% +Well, even the residential is political +suicide. Yeah. So, the residential + + align:start position:0% +suicide. Yeah. So, the residential + + + align:start position:0% +suicide. Yeah. So, the residential +system is actually kind of a bad one + + align:start position:0% +system is actually kind of a bad one + + + align:start position:0% +system is actually kind of a bad one +because if you have like eight people + + align:start position:0% +because if you have like eight people + + + align:start position:0% +because if you have like eight people +living in a house versus two, it doesn't + + align:start position:0% +living in a house versus two, it doesn't + + + align:start position:0% +living in a house versus two, it doesn't +take that into account. So, it's not a + + align:start position:0% +take that into account. So, it's not a + + + align:start position:0% +take that into account. So, it's not a +per capita thing. + + align:start position:0% +per capita thing. + + + align:start position:0% +per capita thing. +Yeah. So um many many states and + + align:start position:0% +Yeah. So um many many states and + + + align:start position:0% +Yeah. So um many many states and +countries have tried to adjust uh + + align:start position:0% +countries have tried to adjust uh + + + align:start position:0% +countries have tried to adjust uh +incentive mechanisms. Uh I'm not sure + + align:start position:0% +incentive mechanisms. Uh I'm not sure + + + align:start position:0% +incentive mechanisms. Uh I'm not sure +specifically about the commercial res + + align:start position:0% +specifically about the commercial res + + + align:start position:0% +specifically about the commercial res +and industrial. You might want to jot it + + align:start position:0% +and industrial. You might want to jot it + + + align:start position:0% +and industrial. You might want to jot it +down and give a quick Google search + + align:start position:0% +down and give a quick Google search + + + align:start position:0% +down and give a quick Google search +after. Um Germany growing gang busters + + align:start position:0% +after. Um Germany growing gang busters + + + align:start position:0% +after. Um Germany growing gang busters +uh the market versus time. This is + + align:start position:0% +uh the market versus time. This is + + + align:start position:0% +uh the market versus time. This is +installed capacity annual versus year. + + align:start position:0% +installed capacity annual versus year. + + + align:start position:0% +installed capacity annual versus year. +And uh we again subsidy support + + align:start position:0% +And uh we again subsidy support + + + align:start position:0% +And uh we again subsidy support +mechanisms, tax breaks, incentives. Um, + + align:start position:0% +mechanisms, tax breaks, incentives. Um, + + + align:start position:0% +mechanisms, tax breaks, incentives. Um, +what we wanted to to emphasize here was + + align:start position:0% +what we wanted to to emphasize here was + + + align:start position:0% +what we wanted to to emphasize here was +that Germany is not one of the sunnier + + align:start position:0% +that Germany is not one of the sunnier + + + align:start position:0% +that Germany is not one of the sunnier +places in the world. Look at this. It + + align:start position:0% +places in the world. Look at this. It + + + align:start position:0% +places in the world. Look at this. It +has almost half of the modules + + align:start position:0% +has almost half of the modules + + + align:start position:0% +has almost half of the modules +installed. And yet, um, oopsie, go back + + align:start position:0% +installed. And yet, um, oopsie, go back + + + align:start position:0% +installed. And yet, um, oopsie, go back +one. Uh, it has less insulation than + + align:start position:0% +one. Uh, it has less insulation than + + + align:start position:0% +one. Uh, it has less insulation than +even here in the US northeast. Even the + + align:start position:0% +even here in the US northeast. Even the + + + align:start position:0% +even here in the US northeast. Even the +sunniest places in Germany. This is + + align:start position:0% +sunniest places in Germany. This is + + + align:start position:0% +sunniest places in Germany. This is +Bavaria. This is the place that hits 40% + + align:start position:0% +Bavaria. This is the place that hits 40% + + + align:start position:0% +Bavaria. This is the place that hits 40% +of electricity on on peak summer days + + align:start position:0% +of electricity on on peak summer days + + + align:start position:0% +of electricity on on peak summer days +coming from PV. And this is the this is + + align:start position:0% +coming from PV. And this is the this is + + + align:start position:0% +coming from PV. And this is the this is +where we are right up there. Same + + align:start position:0% +where we are right up there. Same + + + align:start position:0% +where we are right up there. Same +scale, right? So something's going on in + + align:start position:0% +scale, right? So something's going on in + + + align:start position:0% +scale, right? So something's going on in +Germany and it's not uh it's not sun. Um + + align:start position:0% +Germany and it's not uh it's not sun. Um + + + align:start position:0% +Germany and it's not uh it's not sun. Um +the uh the German government instituted + + align:start position:0% +the uh the German government instituted + + + align:start position:0% +the uh the German government instituted +a number this little D represents + + align:start position:0% +a number this little D represents + + + align:start position:0% +a number this little D represents +Deutseland Germany uh implemented a + + align:start position:0% +Deutseland Germany uh implemented a + + + align:start position:0% +Deutseland Germany uh implemented a +number of incentive programs to increase + + align:start position:0% +number of incentive programs to increase + + + align:start position:0% +number of incentive programs to increase +the amount of PV uh installed on the + + align:start position:0% +the amount of PV uh installed on the + + + align:start position:0% +the amount of PV uh installed on the +grid under the assumption that if they + + align:start position:0% +grid under the assumption that if they + + + align:start position:0% +grid under the assumption that if they +had a demand pull they would have a + + align:start position:0% +had a demand pull they would have a + + + align:start position:0% +had a demand pull they would have a +supply push, meaning they would start up + + align:start position:0% +supply push, meaning they would start up + + + align:start position:0% +supply push, meaning they would start up +local industries. Um initially didn't + + align:start position:0% +local industries. Um initially didn't + + + align:start position:0% +local industries. Um initially didn't +quite take off as fast as they hoped. So + + align:start position:0% +quite take off as fast as they hoped. So + + + align:start position:0% +quite take off as fast as they hoped. So +they began providing direct + + align:start position:0% +they began providing direct + + + align:start position:0% +they began providing direct +manufacturing support, direct subsidies + + align:start position:0% +manufacturing support, direct subsidies + + + align:start position:0% +manufacturing support, direct subsidies +to install uh PV manufacturing plants to + + align:start position:0% +to install uh PV manufacturing plants to + + + align:start position:0% +to install uh PV manufacturing plants to +the point where they were willing to pay + + align:start position:0% +the point where they were willing to pay + + + align:start position:0% +the point where they were willing to pay +uh 50 euro cents in the euro uh for each + + align:start position:0% +uh 50 euro cents in the euro uh for each + + + align:start position:0% +uh 50 euro cents in the euro uh for each +uh piece of capital equipment that moved + + align:start position:0% +uh piece of capital equipment that moved + + + align:start position:0% +uh piece of capital equipment that moved +in on German soil to produce plants in + + align:start position:0% +in on German soil to produce plants in + + + align:start position:0% +in on German soil to produce plants in +the mid-200s. Uh so that combination of + + align:start position:0% +the mid-200s. Uh so that combination of + + + align:start position:0% +the mid-200s. Uh so that combination of +of of of events left them with booming + + align:start position:0% +of of of events left them with booming + + + align:start position:0% +of of of events left them with booming +market upwards of 100,000 jobs I believe + + align:start position:0% +market upwards of 100,000 jobs I believe + + + align:start position:0% +market upwards of 100,000 jobs I believe +in in Germany related to PV + + align:start position:0% +in in Germany related to PV + + + align:start position:0% +in in Germany related to PV +manufacturing and a lot of PV installed + + align:start position:0% +manufacturing and a lot of PV installed + + + align:start position:0% +manufacturing and a lot of PV installed +on their grid um as a result of the + + align:start position:0% +on their grid um as a result of the + + + align:start position:0% +on their grid um as a result of the +market pull. So really when it comes to + + align:start position:0% +market pull. So really when it comes to + + + align:start position:0% +market pull. So really when it comes to +subsidies and support you have to + + align:start position:0% +subsidies and support you have to + + + align:start position:0% +subsidies and support you have to +decouple what is market pull which means + + align:start position:0% +decouple what is market pull which means + + + align:start position:0% +decouple what is market pull which means +we want PV installed on our grid to + + align:start position:0% +we want PV installed on our grid to + + + align:start position:0% +we want PV installed on our grid to +offset our glo our our country's carbon + + align:start position:0% +offset our glo our our country's carbon + + + align:start position:0% +offset our glo our our country's carbon +emissions um versus manufacturing push + + align:start position:0% +emissions um versus manufacturing push + + + align:start position:0% +emissions um versus manufacturing push +which is to say you want to set up a + + align:start position:0% +which is to say you want to set up a + + + align:start position:0% +which is to say you want to set up a +factory in my country fine come right in + + align:start position:0% +factory in my country fine come right in + + + align:start position:0% +factory in my country fine come right in +I'll provide you the finances I'll + + align:start position:0% +I'll provide you the finances I'll + + + align:start position:0% +I'll provide you the finances I'll +provide you a lower cost of capital on + + align:start position:0% +provide you a lower cost of capital on + + + align:start position:0% +provide you a lower cost of capital on +your loan or um help you uh by providing + + align:start position:0% +your loan or um help you uh by providing + + + align:start position:0% +your loan or um help you uh by providing +a direct grant or loan um and and this + + align:start position:0% +a direct grant or loan um and and this + + + align:start position:0% +a direct grant or loan um and and this +is uh these are two different support + + align:start position:0% +is uh these are two different support + + + align:start position:0% +is uh these are two different support +mechanisms and that's why you see that + + align:start position:0% +mechanisms and that's why you see that + + + align:start position:0% +mechanisms and that's why you see that +dichotomy + + align:start position:0% +dichotomy + + + align:start position:0% +dichotomy +uh between Germany which installs a lot + + align:start position:0% +uh between Germany which installs a lot + + + align:start position:0% +uh between Germany which installs a lot +of PV and has a decent amount of + + align:start position:0% +of PV and has a decent amount of + + + align:start position:0% +of PV and has a decent amount of +manufacturing, the US which has a lot of + + align:start position:0% +manufacturing, the US which has a lot of + + + align:start position:0% +manufacturing, the US which has a lot of +installation but not a whole lot of + + align:start position:0% +installation but not a whole lot of + + + align:start position:0% +installation but not a whole lot of +manufacturing uh traditionally although + + align:start position:0% +manufacturing uh traditionally although + + + align:start position:0% +manufacturing uh traditionally although +that's changed the support has changed + + align:start position:0% +that's changed the support has changed + + + align:start position:0% +that's changed the support has changed +over the last three years and uh China + + align:start position:0% +over the last three years and uh China + + + align:start position:0% +over the last three years and uh China +which has a heck of a lot of + + align:start position:0% +which has a heck of a lot of + + + align:start position:0% +which has a heck of a lot of +manufacturing but not a whole lot of + + align:start position:0% +manufacturing but not a whole lot of + + + align:start position:0% +manufacturing but not a whole lot of +local demand. It's because each country + + align:start position:0% +local demand. It's because each country + + + align:start position:0% +local demand. It's because each country +has adopted a different approach uh + + align:start position:0% +has adopted a different approach uh + + + align:start position:0% +has adopted a different approach uh +based on optimization of different + + align:start position:0% +based on optimization of different + + + align:start position:0% +based on optimization of different +functions. in terms of where um where a + + align:start position:0% +functions. in terms of where um where a + + + align:start position:0% +functions. in terms of where um where a +lot has happened on the state level. Um + + align:start position:0% +lot has happened on the state level. Um + + + align:start position:0% +lot has happened on the state level. Um +the these are RPS renewable portfolio + + align:start position:0% +the these are RPS renewable portfolio + + + align:start position:0% +the these are RPS renewable portfolio +standard policies with solar and + + align:start position:0% +standard policies with solar and + + + align:start position:0% +standard policies with solar and +distributed generation provisions uh + + align:start position:0% +distributed generation provisions uh + + + align:start position:0% +distributed generation provisions uh +distributed throughout the United + + align:start position:0% +distributed throughout the United + + + align:start position:0% +distributed throughout the United +States. And you can see that the states + + align:start position:0% +States. And you can see that the states + + + align:start position:0% +States. And you can see that the states +have picked up where the federal + + align:start position:0% +have picked up where the federal + + + align:start position:0% +have picked up where the federal +government lacked in terms of leadership + + align:start position:0% +government lacked in terms of leadership + + + align:start position:0% +government lacked in terms of leadership +right in terms of getting PV on the + + align:start position:0% +right in terms of getting PV on the + + + align:start position:0% +right in terms of getting PV on the +grid. The states really uh pulled hard + + align:start position:0% +grid. The states really uh pulled hard + + + align:start position:0% +grid. The states really uh pulled hard +in specifically New Jersey. Some really + + align:start position:0% +in specifically New Jersey. Some really + + + align:start position:0% +in specifically New Jersey. Some really +oddball states like New Jersey here + + align:start position:0% +oddball states like New Jersey here + + + align:start position:0% +oddball states like New Jersey here +installing about 5 gawatts of solar. Um, + + align:start position:0% +installing about 5 gawatts of solar. Um, + + + align:start position:0% +installing about 5 gawatts of solar. Um, +California had uh another uh more more + + align:start position:0% +California had uh another uh more more + + + align:start position:0% +California had uh another uh more more +of a market pull mechanism. Um, rebate + + align:start position:0% +of a market pull mechanism. Um, rebate + + + align:start position:0% +of a market pull mechanism. Um, rebate +programs for renewables. This is if you + + align:start position:0% +programs for renewables. This is if you + + + align:start position:0% +programs for renewables. This is if you +install uh solar panels, you might get a + + align:start position:0% +install uh solar panels, you might get a + + + align:start position:0% +install uh solar panels, you might get a +few thousand dollars back uh from the + + align:start position:0% +few thousand dollars back uh from the + + + align:start position:0% +few thousand dollars back uh from the +state government. And um it just gives + + align:start position:0% +state government. And um it just gives + + + align:start position:0% +state government. And um it just gives +you a sense of of how the states have + + align:start position:0% +you a sense of of how the states have + + + align:start position:0% +you a sense of of how the states have +filled in that void uh where the federal + + align:start position:0% +filled in that void uh where the federal + + + align:start position:0% +filled in that void uh where the federal +government didn't uh uh uh step in. And + + align:start position:0% +government didn't uh uh uh step in. And + + + align:start position:0% +government didn't uh uh uh step in. And +this has come in part to our detriment. + + align:start position:0% +this has come in part to our detriment. + + + align:start position:0% +this has come in part to our detriment. +nice because we can allow the the + + align:start position:0% +nice because we can allow the the + + + align:start position:0% +nice because we can allow the the +federalist approach allows individual + + align:start position:0% +federalist approach allows individual + + + align:start position:0% +federalist approach allows individual +states to say, "Hey, we prioritize green + + align:start position:0% +states to say, "Hey, we prioritize green + + + align:start position:0% +states to say, "Hey, we prioritize green +jobs. All right, let's let's support it. + + align:start position:0% +jobs. All right, let's let's support it. + + + align:start position:0% +jobs. All right, let's let's support it. +Let's make it happen." And that's + + align:start position:0% +Let's make it happen." And that's + + + align:start position:0% +Let's make it happen." And that's +certainly Massachusetts take, + + align:start position:0% +certainly Massachusetts take, + + + align:start position:0% +certainly Massachusetts take, +California, uh Texas, certain other + + align:start position:0% +California, uh Texas, certain other + + + align:start position:0% +California, uh Texas, certain other +countries throughout the US, uh certain + + align:start position:0% +countries throughout the US, uh certain + + + align:start position:0% +countries throughout the US, uh certain +other states throughout the US, um + + align:start position:0% +other states throughout the US, um + + + align:start position:0% +other states throughout the US, um +including Mississippi most recently. Um + + align:start position:0% +including Mississippi most recently. Um + + + align:start position:0% +including Mississippi most recently. Um +but the downside of that is that you + + align:start position:0% +but the downside of that is that you + + + align:start position:0% +but the downside of that is that you +have each state doing its own thing, + + align:start position:0% +have each state doing its own thing, + + + align:start position:0% +have each state doing its own thing, +each municipality, each local uh + + align:start position:0% +each municipality, each local uh + + + align:start position:0% +each municipality, each local uh +electric utility grid doing its own + + align:start position:0% +electric utility grid doing its own + + + align:start position:0% +electric utility grid doing its own +thing. And what can happen is uh + + align:start position:0% +thing. And what can happen is uh + + + align:start position:0% +thing. And what can happen is uh +diversification of support mechanisms + + align:start position:0% +diversification of support mechanisms + + + align:start position:0% +diversification of support mechanisms +and incentives to the point now that if + + align:start position:0% +and incentives to the point now that if + + + align:start position:0% +and incentives to the point now that if +you want to install panels on your roof + + align:start position:0% +you want to install panels on your roof + + + align:start position:0% +you want to install panels on your roof +in the United States, there are over + + align:start position:0% +in the United States, there are over + + + align:start position:0% +in the United States, there are over +18,000 ways you could do it within the + + align:start position:0% +18,000 ways you could do it within the + + + align:start position:0% +18,000 ways you could do it within the +US alone, 18,000 unique types of + + align:start position:0% +US alone, 18,000 unique types of + + + align:start position:0% +US alone, 18,000 unique types of +paperwork that you have to fill out uh + + align:start position:0% +paperwork that you have to fill out uh + + + align:start position:0% +paperwork that you have to fill out uh +depending on where you are in the United + + align:start position:0% +depending on where you are in the United + + + align:start position:0% +depending on where you are in the United +States. In Germany, you have one unified + + align:start position:0% +States. In Germany, you have one unified + + + align:start position:0% +States. In Germany, you have one unified +paperwork for the entire country and + + align:start position:0% +paperwork for the entire country and + + + align:start position:0% +paperwork for the entire country and +it's very short. I believe it's two + + align:start position:0% +it's very short. I believe it's two + + + align:start position:0% +it's very short. I believe it's two +pages. And in the United States, you can + + align:start position:0% +pages. And in the United States, you can + + + align:start position:0% +pages. And in the United States, you can +fill out a few reams of paper. Um, one + + align:start position:0% +fill out a few reams of paper. Um, one + + + align:start position:0% +fill out a few reams of paper. Um, one +of our our friends in California once + + align:start position:0% +of our our friends in California once + + + align:start position:0% +of our our friends in California once +estimated it takes about a dollar a watt + + align:start position:0% +estimated it takes about a dollar a watt + + + align:start position:0% +estimated it takes about a dollar a watt +uh to uh fill out paperwork um and to + + align:start position:0% +uh to uh fill out paperwork um and to + + + align:start position:0% +uh to uh fill out paperwork um and to +get certifications and so forth. Maybe + + align:start position:0% +get certifications and so forth. Maybe + + + align:start position:0% +get certifications and so forth. Maybe +it was a little bit of an exaggeration, + + align:start position:0% +it was a little bit of an exaggeration, + + + align:start position:0% +it was a little bit of an exaggeration, +but the price is high. And so recently, + + align:start position:0% +but the price is high. And so recently, + + + align:start position:0% +but the price is high. And so recently, +the DOE has attempted to address this as + + align:start position:0% +the DOE has attempted to address this as + + + align:start position:0% +the DOE has attempted to address this as +well by fostering a race to the top type + + align:start position:0% +well by fostering a race to the top type + + + align:start position:0% +well by fostering a race to the top type +uh incentive mechanism for states to uh + + align:start position:0% +uh incentive mechanism for states to uh + + + align:start position:0% +uh incentive mechanism for states to uh +facilitate in installation. But still in + + align:start position:0% +facilitate in installation. But still in + + + align:start position:0% +facilitate in installation. But still in +in Massachusetts we had remember for the + + align:start position:0% +in Massachusetts we had remember for the + + + align:start position:0% +in Massachusetts we had remember for the +system on my roof we had at least two + + align:start position:0% +system on my roof we had at least two + + + align:start position:0% +system on my roof we had at least two +inspectors come by from different + + align:start position:0% +inspectors come by from different + + + align:start position:0% +inspectors come by from different +agencies that could have been + + align:start position:0% +agencies that could have been + + + align:start position:0% +agencies that could have been +consolidated into one. Right? So while + + align:start position:0% +consolidated into one. Right? So while + + + align:start position:0% +consolidated into one. Right? So while +state independence is good and local + + align:start position:0% +state independence is good and local + + + align:start position:0% +state independence is good and local +utility independence is great from the + + align:start position:0% +utility independence is great from the + + + align:start position:0% +utility independence is great from the +perspective the federal government is + + align:start position:0% +perspective the federal government is + + + align:start position:0% +perspective the federal government is +lacking in terms of moving forward. The + + align:start position:0% +lacking in terms of moving forward. The + + + align:start position:0% +lacking in terms of moving forward. The +states can push forward at their + + align:start position:0% +states can push forward at their + + + align:start position:0% +states can push forward at their +comfortable speed. On the flip on the + + align:start position:0% +comfortable speed. On the flip on the + + + align:start position:0% +comfortable speed. On the flip on the +downside, it makes it very difficult for + + align:start position:0% +downside, it makes it very difficult for + + + align:start position:0% +downside, it makes it very difficult for +an installer company to reduce its uh + + align:start position:0% +an installer company to reduce its uh + + + align:start position:0% +an installer company to reduce its uh +costs because it has to address a + + align:start position:0% +costs because it has to address a + + + align:start position:0% +costs because it has to address a +multitude of local markets uh throughout + + align:start position:0% +multitude of local markets uh throughout + + + align:start position:0% +multitude of local markets uh throughout +the US and that uh adds adds to cost. In + + align:start position:0% +the US and that uh adds adds to cost. In + + + align:start position:0% +the US and that uh adds adds to cost. In +terms of projections, I really hesitate + + align:start position:0% +terms of projections, I really hesitate + + + align:start position:0% +terms of projections, I really hesitate +because in 2006, there were a number of + + align:start position:0% +because in 2006, there were a number of + + + align:start position:0% +because in 2006, there were a number of +projections of where we'd be in + + align:start position:0% +projections of where we'd be in + + + align:start position:0% +projections of where we'd be in +2010. And um and many of them you can + + align:start position:0% +2010. And um and many of them you can + + + align:start position:0% +2010. And um and many of them you can +see the range here going from 4 gawatt + + align:start position:0% +see the range here going from 4 gawatt + + + align:start position:0% +see the range here going from 4 gawatt +up to actually I think uh photon + + align:start position:0% +up to actually I think uh photon + + + align:start position:0% +up to actually I think uh photon +consulting had us close to 30 gigawatts + + align:start position:0% +consulting had us close to 30 gigawatts + + + align:start position:0% +consulting had us close to 30 gigawatts +back in uh in + + align:start position:0% +back in uh in + + + align:start position:0% +back in uh in +2010. Um photon consulting was closer to + + align:start position:0% +2010. Um photon consulting was closer to + + + align:start position:0% +2010. Um photon consulting was closer to +right than than most of the other + + align:start position:0% +right than than most of the other + + + align:start position:0% +right than than most of the other +groups. Interestingly, um the 4 gawatts + + align:start position:0% +groups. Interestingly, um the 4 gawatts + + + align:start position:0% +groups. Interestingly, um the 4 gawatts +was was obviously pretty far off. So + + align:start position:0% +was was obviously pretty far off. So + + + align:start position:0% +was was obviously pretty far off. So +projections are very dangerous because + + align:start position:0% +projections are very dangerous because + + + align:start position:0% +projections are very dangerous because +you could be easily wrong. Right? This + + align:start position:0% +you could be easily wrong. Right? This + + + align:start position:0% +you could be easily wrong. Right? This +is just to just to show you an example. + + align:start position:0% +is just to just to show you an example. + + + align:start position:0% +is just to just to show you an example. +Um these are projections of where the + + align:start position:0% +Um these are projections of where the + + + align:start position:0% +Um these are projections of where the +solar market is going to go. Um from the + + align:start position:0% +solar market is going to go. Um from the + + + align:start position:0% +solar market is going to go. Um from the +EPIA, which is the European Photoex + + align:start position:0% +EPIA, which is the European Photoex + + + align:start position:0% +EPIA, which is the European Photoex +Industry Association, um it's one of the + + align:start position:0% +Industry Association, um it's one of the + + + align:start position:0% +Industry Association, um it's one of the +better sources that I could find with + + align:start position:0% +better sources that I could find with + + + align:start position:0% +better sources that I could find with +the various scenarios giving you an + + align:start position:0% +the various scenarios giving you an + + + align:start position:0% +the various scenarios giving you an +indication, a tornado plot, if you will, + + align:start position:0% +indication, a tornado plot, if you will, + + + align:start position:0% +indication, a tornado plot, if you will, +of where the uh where the um market is + + align:start position:0% +of where the uh where the um market is + + + align:start position:0% +of where the uh where the um market is +is going to head over the future. And + + align:start position:0% +is going to head over the future. And + + + align:start position:0% +is going to head over the future. And +the bottom line is that most likely it + + align:start position:0% +the bottom line is that most likely it + + + align:start position:0% +the bottom line is that most likely it +will continue to grow even though it's + + align:start position:0% +will continue to grow even though it's + + + align:start position:0% +will continue to grow even though it's +going to enter a difficult year, + + align:start position:0% +going to enter a difficult year, + + + align:start position:0% +going to enter a difficult year, +difficult two years as the over supply + + align:start position:0% +difficult two years as the over supply + + + align:start position:0% +difficult two years as the over supply +condition work itself out of the market. + + align:start position:0% +condition work itself out of the market. + + + align:start position:0% +condition work itself out of the market. +Uh we're headed for some pretty massive + + align:start position:0% +Uh we're headed for some pretty massive + + + align:start position:0% +Uh we're headed for some pretty massive +growth. And just keep those numbers in + + align:start position:0% +growth. And just keep those numbers in + + + align:start position:0% +growth. And just keep those numbers in +mind. If if this grows up to be say a + + align:start position:0% +mind. If if this grows up to be say a + + + align:start position:0% +mind. If if this grows up to be say a +100 gawatt uh industry and there's two + + align:start position:0% +100 gawatt uh industry and there's two + + + align:start position:0% +100 gawatt uh industry and there's two +people per megawatt, that's 200,000 + + align:start position:0% +people per megawatt, that's 200,000 + + + align:start position:0% +people per megawatt, that's 200,000 +people employed just in the + + align:start position:0% +people employed just in the + + + align:start position:0% +people employed just in the +manufacturing of modules, right? Um not + + align:start position:0% +manufacturing of modules, right? Um not + + + align:start position:0% +manufacturing of modules, right? Um not +counting all of the other people on top + + align:start position:0% +counting all of the other people on top + + + align:start position:0% +counting all of the other people on top +of that. maybe another order of + + align:start position:0% +of that. maybe another order of + + + align:start position:0% +of that. maybe another order of +magnitude if we use the car industry as + + align:start position:0% +magnitude if we use the car industry as + + + align:start position:0% +magnitude if we use the car industry as +an example. Uh so we could be looking at + + align:start position:0% +an example. Uh so we could be looking at + + + align:start position:0% +an example. Uh so we could be looking at +two million jobs worldwide. Uh right and + + align:start position:0% +two million jobs worldwide. Uh right and + + + align:start position:0% +two million jobs worldwide. Uh right and +uh where they are um who works on them. + + align:start position:0% +uh where they are um who works on them. + + + align:start position:0% +uh where they are um who works on them. +Uh how the value chain is distributed + + align:start position:0% +Uh how the value chain is distributed + + + align:start position:0% +Uh how the value chain is distributed +between R&D uh manufacturing. Um this is + + align:start position:0% +between R&D uh manufacturing. Um this is + + + align:start position:0% +between R&D uh manufacturing. Um this is +all all open. The next decade will + + align:start position:0% +all all open. The next decade will + + + align:start position:0% +all all open. The next decade will +decide that you'll help decide that. So + + align:start position:0% +decide that you'll help decide that. So + + + align:start position:0% +decide that you'll help decide that. So +uh with that message I'd let you go. \ No newline at end of file diff --git a/nG47fQ-aiHw.txt b/nG47fQ-aiHw.txt new file mode 100644 index 0000000000000000000000000000000000000000..2b82a64fd0d8d827f706956d78be9c4e976b96b1 --- /dev/null +++ b/nG47fQ-aiHw.txt @@ -0,0 +1,7251 @@ +align:start position:0% + +so I think we can start so welcome to my + + align:start position:0% +so I think we can start so welcome to my + + + align:start position:0% +so I think we can start so welcome to my +lecture today we are going to learn + + align:start position:0% +lecture today we are going to learn + + + align:start position:0% +lecture today we are going to learn +about the switching lws and snubbers so + + align:start position:0% +about the switching lws and snubbers so + + + align:start position:0% +about the switching lws and snubbers so +before that I would like to have a quick + + align:start position:0% +before that I would like to have a quick + + + align:start position:0% +before that I would like to have a quick +review about our devices so one of the + + align:start position:0% +review about our devices so one of the + + + align:start position:0% +review about our devices so one of the +same Power Electronics de is is about + + align:start position:0% +same Power Electronics de is is about + + + align:start position:0% +same Power Electronics de is is about +the circuits and now these circuits play + + align:start position:0% +the circuits and now these circuits play + + + align:start position:0% +the circuits and now these circuits play +with the transistors and the transistors + + align:start position:0% +with the transistors and the transistors + + + align:start position:0% +with the transistors and the transistors +can be a bipolar trans istor or the fuel + + align:start position:0% +can be a bipolar trans istor or the fuel + + + align:start position:0% +can be a bipolar trans istor or the fuel +effect transistors so we use transistors + + align:start position:0% +effect transistors so we use transistors + + + align:start position:0% +effect transistors so we use transistors +as switches which is on and off and + + align:start position:0% +as switches which is on and off and + + + align:start position:0% +as switches which is on and off and +other analog circuits or Advanced analog + + align:start position:0% +other analog circuits or Advanced analog + + + align:start position:0% +other analog circuits or Advanced analog +circuits they use transistors as a + + align:start position:0% +circuits they use transistors as a + + + align:start position:0% +circuits they use transistors as a +current source and for the switches we + + align:start position:0% +current source and for the switches we + + + align:start position:0% +current source and for the switches we +are focusing on there could be ideal + + align:start position:0% +are focusing on there could be ideal + + + align:start position:0% +are focusing on there could be ideal +switches or practical switches for ideal + + align:start position:0% +switches or practical switches for ideal + + + align:start position:0% +switches or practical switches for ideal +switches we we we we assume the switches + + align:start position:0% +switches we we we we assume the switches + + + align:start position:0% +switches we we we we assume the switches +will inst continuously turn on and turn + + align:start position:0% +will inst continuously turn on and turn + + + align:start position:0% +will inst continuously turn on and turn +off and also during the switch on state + + align:start position:0% +off and also during the switch on state + + + align:start position:0% +off and also during the switch on state +there is no voltage drop or the resistor + + align:start position:0% +there is no voltage drop or the resistor + + + align:start position:0% +there is no voltage drop or the resistor +is zero and it can carry both positive + + align:start position:0% +is zero and it can carry both positive + + + align:start position:0% +is zero and it can carry both positive +and negative current and when the switch + + align:start position:0% +and negative current and when the switch + + + align:start position:0% +and negative current and when the switch +is off we said there will be a infinite + + align:start position:0% +is off we said there will be a infinite + + + align:start position:0% +is off we said there will be a infinite +resistor and there is no leakage current + + align:start position:0% +resistor and there is no leakage current + + + align:start position:0% +resistor and there is no leakage current +and it can also block positive voltage + + align:start position:0% +and it can also block positive voltage + + + align:start position:0% +and it can also block positive voltage +and negative voltage and also for + + align:start position:0% +and negative voltage and also for + + + align:start position:0% +and negative voltage and also for +parasitics we assume the ideal switch + + align:start position:0% +parasitics we assume the ideal switch + + + align:start position:0% +parasitics we assume the ideal switch +has no parasitics and because of this + + align:start position:0% +has no parasitics and because of this + + + align:start position:0% +has no parasitics and because of this +characteristics we said that there is no + + align:start position:0% +characteristics we said that there is no + + + align:start position:0% +characteristics we said that there is no +loss if we use the ideal switches + + align:start position:0% +loss if we use the ideal switches + + + align:start position:0% +loss if we use the ideal switches +however for reality mostly we use the + + align:start position:0% +however for reality mostly we use the + + + align:start position:0% +however for reality mostly we use the +Practical switches so at least some + + align:start position:0% +Practical switches so at least some + + + align:start position:0% +Practical switches so at least some +partical switches in the in the Lector + + align:start position:0% +partical switches in the in the Lector + + + align:start position:0% +partical switches in the in the Lector +nodes that is like BJT igbt CER which is + + align:start position:0% +nodes that is like BJT igbt CER which is + + + align:start position:0% +nodes that is like BJT igbt CER which is +also called CSR or a diode or these days + + align:start position:0% +also called CSR or a diode or these days + + + align:start position:0% +also called CSR or a diode or these days +we use mostly about the most fat or the + + align:start position:0% +we use mostly about the most fat or the + + + align:start position:0% +we use mostly about the most fat or the +wide band Gap gum nitride fat and for + + align:start position:0% +wide band Gap gum nitride fat and for + + + align:start position:0% +wide band Gap gum nitride fat and for +this practical switches they need some + + align:start position:0% +this practical switches they need some + + + align:start position:0% +this practical switches they need some +finite time to turn on and turn off and + + align:start position:0% +finite time to turn on and turn off and + + + align:start position:0% +finite time to turn on and turn off and +also when the switch is during its on + + align:start position:0% +also when the switch is during its on + + + align:start position:0% +also when the switch is during its on +state there is a finite voltage drop or + + align:start position:0% +state there is a finite voltage drop or + + + align:start position:0% +state there is a finite voltage drop or +a finite small resistors and the current + + align:start position:0% +a finite small resistors and the current + + + align:start position:0% +a finite small resistors and the current +it can carry has some polarity so let + + align:start position:0% +it can carry has some polarity so let + + + align:start position:0% +it can carry has some polarity so let +say for the BJT it can only carry the + + align:start position:0% +say for the BJT it can only carry the + + + align:start position:0% +say for the BJT it can only carry the +positive current but for most fat it can + + align:start position:0% +positive current but for most fat it can + + + align:start position:0% +positive current but for most fat it can +carry both positive and negative current + + align:start position:0% +carry both positive and negative current + + + align:start position:0% +carry both positive and negative current +and also when the switch is off the off + + align:start position:0% +and also when the switch is off the off + + + align:start position:0% +and also when the switch is off the off +resistor will be very big so there could + + align:start position:0% +resistor will be very big so there could + + + align:start position:0% +resistor will be very big so there could +be some leakage current and also the + + align:start position:0% +be some leakage current and also the + + + align:start position:0% +be some leakage current and also the +blocking voltage also has a polar + + align:start position:0% +blocking voltage also has a polar + + + align:start position:0% +blocking voltage also has a polar +polarity and because of this and also + + align:start position:0% +polarity and because of this and also + + + align:start position:0% +polarity and because of this and also +for parasitics we usually have a + + align:start position:0% +for parasitics we usually have a + + + align:start position:0% +for parasitics we usually have a +parallel capacitance in parallel with + + align:start position:0% +parallel capacitance in parallel with + + + align:start position:0% +parallel capacitance in parallel with +the switch and also some switches will + + align:start position:0% +the switch and also some switches will + + + align:start position:0% +the switch and also some switches will +have a anti parallel dial inside of them + + align:start position:0% +have a anti parallel dial inside of them + + + align:start position:0% +have a anti parallel dial inside of them +and because of this non ideal factors + + align:start position:0% +and because of this non ideal factors + + + align:start position:0% +and because of this non ideal factors +there will be some nonzero losses and + + align:start position:0% +there will be some nonzero losses and + + + align:start position:0% +there will be some nonzero losses and +the losses could be conduction loss + + align:start position:0% +the losses could be conduction loss + + + align:start position:0% +the losses could be conduction loss +during the on state all the switching + + align:start position:0% +during the on state all the switching + + + align:start position:0% +during the on state all the switching +loss when we switch turn on and turn off + + align:start position:0% +loss when we switch turn on and turn off + + + align:start position:0% +loss when we switch turn on and turn off +and also we could have some gting losss + + align:start position:0% +and also we could have some gting losss + + + align:start position:0% +and also we could have some gting losss +and some other losss so this is a quick + + align:start position:0% +and some other losss so this is a quick + + + align:start position:0% +and some other losss so this is a quick +review about our transistor and today we + + align:start position:0% +review about our transistor and today we + + + align:start position:0% +review about our transistor and today we +were focusing on the switching loss and + + align:start position:0% +were focusing on the switching loss and + + + align:start position:0% +were focusing on the switching loss and +the corresponding method to minim to to + + align:start position:0% +the corresponding method to minim to to + + + align:start position:0% +the corresponding method to minim to to +improve with the switching loss that we + + align:start position:0% +improve with the switching loss that we + + + align:start position:0% +improve with the switching loss that we +call it snubbers so let's take the most + + align:start position:0% +call it snubbers so let's take the most + + + align:start position:0% +call it snubbers so let's take the most +basic circuit B converter as an example + + align:start position:0% +basic circuit B converter as an example + + + align:start position:0% +basic circuit B converter as an example +so we have a input voltage source and we + + align:start position:0% +so we have a input voltage source and we + + + align:start position:0% +so we have a input voltage source and we +have we can have a practical switch that + + align:start position:0% +have we can have a practical switch that + + + align:start position:0% +have we can have a practical switch that +is a m fat and we can have a dial + + align:start position:0% +is a m fat and we can have a dial + + + align:start position:0% +is a m fat and we can have a dial +here and usually we will have a low pass + + align:start position:0% +here and usually we will have a low pass + + + align:start position:0% +here and usually we will have a low pass +filter L and + + align:start position:0% +filter L and + + + align:start position:0% +filter L and +c and also a resistor + + align:start position:0% +c and also a resistor + + + align:start position:0% +c and also a resistor +here so if we assume that the current + + align:start position:0% +here so if we assume that the current + + + align:start position:0% +here so if we assume that the current +flows through this inductor is constant + + align:start position:0% +flows through this inductor is constant + + + align:start position:0% +flows through this inductor is constant +which is there is no Ripple here and + + align:start position:0% +which is there is no Ripple here and + + + align:start position:0% +which is there is no Ripple here and +this inductor is pretty big and then we + + align:start position:0% +this inductor is pretty big and then we + + + align:start position:0% +this inductor is pretty big and then we +can model our circuit + + align:start position:0% +can model our circuit + + + align:start position:0% +can model our circuit +as we still have a input voltage source + + align:start position:0% +as we still have a input voltage source + + + align:start position:0% +as we still have a input voltage source +and we have a MOS + + align:start position:0% +and we have a MOS + + + align:start position:0% +and we have a MOS +fat and we have a diod + + align:start position:0% +fat and we have a diod + + + align:start position:0% +fat and we have a diod +here and now our load will be a constant + + align:start position:0% +here and now our load will be a constant + + + align:start position:0% +here and now our load will be a constant +current + + align:start position:0% +current + + + align:start position:0% +current +source so we have already know the + + align:start position:0% +source so we have already know the + + + align:start position:0% +source so we have already know the +switching pattern of the bar converter + + align:start position:0% +switching pattern of the bar converter + + + align:start position:0% +switching pattern of the bar converter +so let's see for a given switching + + align:start position:0% +so let's see for a given switching + + + align:start position:0% +so let's see for a given switching +period that is from zero to + + align:start position:0% +period that is from zero to + + + align:start position:0% +period that is from zero to +TS from zero to DTS which is the duty + + align:start position:0% +TS from zero to DTS which is the duty + + + align:start position:0% +TS from zero to DTS which is the duty +cycle the active switch all the most fat + + align:start position:0% +cycle the active switch all the most fat + + + align:start position:0% +cycle the active switch all the most fat +will turn on this load current so the + + align:start position:0% +will turn on this load current so the + + + align:start position:0% +will turn on this load current so the +switch current will be a square wave + + align:start position:0% +switch current will be a square wave + + + align:start position:0% +switch current will be a square wave +like this so this will be + + align:start position:0% +like this so this will be + + + align:start position:0% +like this so this will be +isw and for the diode when the switch is + + align:start position:0% +isw and for the diode when the switch is + + + align:start position:0% +isw and for the diode when the switch is +off during the DTs to TS this diode will + + align:start position:0% +off during the DTs to TS this diode will + + + align:start position:0% +off during the DTs to TS this diode will +flow through this load current so that + + align:start position:0% +flow through this load current so that + + + align:start position:0% +flow through this load current so that +will be a current waveform like this and + + align:start position:0% +will be a current waveform like this and + + + align:start position:0% +will be a current waveform like this and +this is a dial current so when we + + align:start position:0% +this is a dial current so when we + + + align:start position:0% +this is a dial current so when we +considering the conduction loss so what + + align:start position:0% +considering the conduction loss so what + + + align:start position:0% +considering the conduction loss so what +is the power conduction loss is still a + + align:start position:0% +is the power conduction loss is still a + + + align:start position:0% +is the power conduction loss is still a +power so what is power power is V * I I + + align:start position:0% +power so what is power power is V * I I + + + align:start position:0% +power so what is power power is V * I I +so for the most fat the conduction loss + + align:start position:0% +so for the most fat the conduction loss + + + align:start position:0% +so for the most fat the conduction loss +will be something + + align:start position:0% +will be something + + + align:start position:0% +will be something +like I RMS squ times onate + + align:start position:0% +like I RMS squ times onate + + + align:start position:0% +like I RMS squ times onate +resistance so which I said before for a + + align:start position:0% +resistance so which I said before for a + + + align:start position:0% +resistance so which I said before for a +switch for a practical switch when it's + + align:start position:0% +switch for a practical switch when it's + + + align:start position:0% +switch for a practical switch when it's +during the on state either it can be a + + align:start position:0% +during the on state either it can be a + + + align:start position:0% +during the on state either it can be a +resistor or voltage drop and for for a + + align:start position:0% +resistor or voltage drop and for for a + + + align:start position:0% +resistor or voltage drop and for for a +most fat it will be a RDS on + + align:start position:0% +most fat it will be a RDS on + + + align:start position:0% +most fat it will be a RDS on +resistor and we can calculate the RMS + + align:start position:0% +resistor and we can calculate the RMS + + + align:start position:0% +resistor and we can calculate the RMS +current for the M fat so that will be + + align:start position:0% +current for the M fat so that will be + + + align:start position:0% +current for the M fat so that will be +the duty cycle time the i² time the + + align:start position:0% + + + + align:start position:0% + +rdsr so this will be the IL for its + + align:start position:0% +rdsr so this will be the IL for its + + + align:start position:0% +rdsr so this will be the IL for its +amplitude and for the + + align:start position:0% +amplitude and for the + + + align:start position:0% +amplitude and for the +diode its conduction loss will be the + + align:start position:0% +diode its conduction loss will be the + + + align:start position:0% +diode its conduction loss will be the +average current of the diod times the + + align:start position:0% +average current of the diod times the + + + align:start position:0% +average current of the diod times the +voltage drop so still the P the loss is + + align:start position:0% +voltage drop so still the P the loss is + + + align:start position:0% +voltage drop so still the P the loss is +a power power is V * I just like for the + + align:start position:0% +a power power is V * I just like for the + + + align:start position:0% +a power power is V * I just like for the +most fat the V will be I * the R so will + + align:start position:0% +most fat the V will be I * the R so will + + + align:start position:0% +most fat the V will be I * the R so will +be the i i RMS squ times the RDS s but + + align:start position:0% +be the i i RMS squ times the RDS s but + + + align:start position:0% +be the i i RMS squ times the RDS s but +for the dial it will be the average + + align:start position:0% +for the dial it will be the average + + + align:start position:0% +for the dial it will be the average +current times the voltage + + align:start position:0% +current times the voltage + + + align:start position:0% +current times the voltage +drop so that will be the Y minus D time + + align:start position:0% +drop so that will be the Y minus D time + + + align:start position:0% +drop so that will be the Y minus D time +itimes the voltage drop of the + + align:start position:0% +itimes the voltage drop of the + + + align:start position:0% +itimes the voltage drop of the +dial so I also list like during its on + + align:start position:0% +dial so I also list like during its on + + + align:start position:0% +dial so I also list like during its on +state the most fat looks like the + + align:start position:0% +state the most fat looks like the + + + align:start position:0% +state the most fat looks like the +resistor and during its un State a diod + + align:start position:0% +resistor and during its un State a diod + + + align:start position:0% +resistor and during its un State a diod +likes looks like a voltage drop and for + + align:start position:0% +likes looks like a voltage drop and for + + + align:start position:0% +likes looks like a voltage drop and for +the BJT or igbt or the icr during its un + + align:start position:0% +the BJT or igbt or the icr during its un + + + align:start position:0% +the BJT or igbt or the icr during its un +state it still looks like a voltage drop + + align:start position:0% +state it still looks like a voltage drop + + + align:start position:0% +state it still looks like a voltage drop +so when you calculate the conduction + + align:start position:0% +so when you calculate the conduction + + + align:start position:0% +so when you calculate the conduction +loss for a BJT igbt or a diode or a Sor + + align:start position:0% +loss for a BJT igbt or a diode or a Sor + + + align:start position:0% +loss for a BJT igbt or a diode or a Sor +you use the average current times the + + align:start position:0% +you use the average current times the + + + align:start position:0% +you use the average current times the +voltage drop and when you calculate the + + align:start position:0% +voltage drop and when you calculate the + + + align:start position:0% +voltage drop and when you calculate the +conduction loss for a most fat or Gallum + + align:start position:0% +conduction loss for a most fat or Gallum + + + align:start position:0% +conduction loss for a most fat or Gallum +nitride fat you use the RMS Square Times + + align:start position:0% +nitride fat you use the RMS Square Times + + + align:start position:0% +nitride fat you use the RMS Square Times +the RDS on so this is about the + + align:start position:0% +the RDS on so this is about the + + + align:start position:0% +the RDS on so this is about the +conduction + + align:start position:0% +conduction + + + align:start position:0% +conduction +loss and also today the semiconductor + + align:start position:0% +loss and also today the semiconductor + + + align:start position:0% +loss and also today the semiconductor +loss is a back of envelope so if you do + + align:start position:0% +loss is a back of envelope so if you do + + + align:start position:0% +loss is a back of envelope so if you do +more research we can model this + + align:start position:0% +more research we can model this + + + align:start position:0% +more research we can model this +conduction loss more precisely but + + align:start position:0% +conduction loss more precisely but + + + align:start position:0% +conduction loss more precisely but +generally speaking this is this can be a + + align:start position:0% +generally speaking this is this can be a + + + align:start position:0% +generally speaking this is this can be a +room of sum for a rough calculation and + + align:start position:0% +room of sum for a rough calculation and + + + align:start position:0% +room of sum for a rough calculation and +it is enough good for our + + align:start position:0% +it is enough good for our + + + align:start position:0% +it is enough good for our +design and for the conduction loss and + + align:start position:0% +design and for the conduction loss and + + + align:start position:0% +design and for the conduction loss and +and for the switching loss it is during + + align:start position:0% +and for the switching loss it is during + + + align:start position:0% +and for the switching loss it is during +the it occurs during the turn on and + + align:start position:0% +the it occurs during the turn on and + + + align:start position:0% +the it occurs during the turn on and +turn off and we need to imagine like + + align:start position:0% +turn off and we need to imagine like + + + align:start position:0% +turn off and we need to imagine like +what will be the waveform for the switch + + align:start position:0% +what will be the waveform for the switch + + + align:start position:0% +what will be the waveform for the switch +current and the switch voltage during + + align:start position:0% +current and the switch voltage during + + + align:start position:0% +current and the switch voltage during +the turn on and the turn off here we + + align:start position:0% +the turn on and the turn off here we + + + align:start position:0% +the turn on and the turn off here we +have assumption our assumption is like + + align:start position:0% +have assumption our assumption is like + + + align:start position:0% +have assumption our assumption is like +we assume the + + align:start position:0% +we assume the + + + align:start position:0% +we assume the +vsw and the isw + + align:start position:0% +vsw and the isw + + + align:start position:0% +vsw and the isw +will be linear during the + + align:start position:0% +will be linear during the + + + align:start position:0% +will be linear during the +transient and here we also assume like + + align:start position:0% +transient and here we also assume like + + + align:start position:0% +transient and here we also assume like +our dial is + + align:start position:0% +our dial is + + + align:start position:0% +our dial is +ideal so what do I mean by an ideal dial + + align:start position:0% +ideal so what do I mean by an ideal dial + + + align:start position:0% +ideal so what do I mean by an ideal dial +it is from the characteristics iway + + align:start position:0% +it is from the characteristics iway + + + align:start position:0% +it is from the characteristics iway +curve this is VD this is ID so a dial + + align:start position:0% +curve this is VD this is ID so a dial + + + align:start position:0% +curve this is VD this is ID so a dial +can conduct any amount of current during + + align:start position:0% +can conduct any amount of current during + + + align:start position:0% +can conduct any amount of current during +its un state with a zero voltage drop + + align:start position:0% +its un state with a zero voltage drop + + + align:start position:0% +its un state with a zero voltage drop +and a diode can block any amount of the + + align:start position:0% +and a diode can block any amount of the + + + align:start position:0% +and a diode can block any amount of the +voltage during its off State so this is + + align:start position:0% +voltage during its off State so this is + + + align:start position:0% +voltage during its off State so this is +the ideal diode + + align:start position:0% +the ideal diode + + + align:start position:0% +the ideal diode +and if we notate this term reference as + + align:start position:0% +and if we notate this term reference as + + + align:start position:0% +and if we notate this term reference as +this is + + align:start position:0% +this is + + + align:start position:0% +this is +vsw this is + + align:start position:0% +vsw this is + + + align:start position:0% +vsw this is +isw and this is + + align:start position:0% +isw and this is + + + align:start position:0% +isw and this is +ID and this is + + align:start position:0% +ID and this is + + + align:start position:0% +ID and this is +VD we can simply have the KCl and kvl + + align:start position:0% +VD we can simply have the KCl and kvl + + + align:start position:0% +VD we can simply have the KCl and kvl +equation for this the KCl equation at + + align:start position:0% +equation for this the KCl equation at + + + align:start position:0% +equation for this the KCl equation at +this note will be I is equal to + + align:start position:0% +this note will be I is equal to + + + align:start position:0% +this note will be I is equal to +isw plus the + + align:start position:0% +isw plus the + + + align:start position:0% +isw plus the +ID and for the kvl equation that will be + + align:start position:0% +ID and for the kvl equation that will be + + + align:start position:0% +ID and for the kvl equation that will be +the v + + align:start position:0% +the v + + + align:start position:0% +the v +in is is equal to the + + align:start position:0% +in is is equal to the + + + align:start position:0% +in is is equal to the +vsw minus the + + align:start position:0% +vsw minus the + + + align:start position:0% +vsw minus the +VD so let's imagine what will be the + + align:start position:0% +VD so let's imagine what will be the + + + align:start position:0% +VD so let's imagine what will be the +current and voltage + + align:start position:0% + + + + align:start position:0% + +waveform so for turning off I would + + align:start position:0% +waveform so for turning off I would + + + align:start position:0% +waveform so for turning off I would +first say that it will be the voltage + + align:start position:0% +first say that it will be the voltage + + + align:start position:0% +first say that it will be the voltage +increase first and when the voltage + + align:start position:0% +increase first and when the voltage + + + align:start position:0% +increase first and when the voltage +increase to its maximum amplitude for + + align:start position:0% +increase to its maximum amplitude for + + + align:start position:0% +increase to its maximum amplitude for +the back convertor it's V in and then + + align:start position:0% +the back convertor it's V in and then + + + align:start position:0% +the back convertor it's V in and then +the current will + + align:start position:0% +the current will + + + align:start position:0% +the current will +drop why it's like this + + align:start position:0% +drop why it's like this + + + align:start position:0% +drop why it's like this +because from this qcl and kvl equation + + align:start position:0% +because from this qcl and kvl equation + + + align:start position:0% +because from this qcl and kvl equation +the diode cannot turn on or carry + + align:start position:0% +the diode cannot turn on or carry + + + align:start position:0% +the diode cannot turn on or carry +current until it has the zero voltage + + align:start position:0% +current until it has the zero voltage + + + align:start position:0% +current until it has the zero voltage +drop so to have the zero voltage drop + + align:start position:0% +drop so to have the zero voltage drop + + + align:start position:0% +drop so to have the zero voltage drop +you need to have the switch voltage vsw + + align:start position:0% +you need to have the switch voltage vsw + + + align:start position:0% +you need to have the switch voltage vsw +to increase to its maximum and when it's + + align:start position:0% +to increase to its maximum and when it's + + + align:start position:0% +to increase to its maximum and when it's +increase to its maximum which is V then + + align:start position:0% +increase to its maximum which is V then + + + align:start position:0% +increase to its maximum which is V then +the VD can become zero and later the + + align:start position:0% +the VD can become zero and later the + + + align:start position:0% +the VD can become zero and later the +dial can conduct the current then then + + align:start position:0% +dial can conduct the current then then + + + align:start position:0% +dial can conduct the current then then +if the dial conducts the current then + + align:start position:0% +if the dial conducts the current then + + + align:start position:0% +if the dial conducts the current then +the isw will decrease so that is during + + align:start position:0% +the isw will decrease so that is during + + + align:start position:0% +the isw will decrease so that is during +the turn off the switch voltage increase + + align:start position:0% +the turn off the switch voltage increase + + + align:start position:0% +the turn off the switch voltage increase +first and then the current and then then + + align:start position:0% +first and then the current and then then + + + align:start position:0% +first and then the current and then then +the switch current decrease + + align:start position:0% +the switch current decrease + + + align:start position:0% +the switch current decrease +later and similarly during the turn on + + align:start position:0% +later and similarly during the turn on + + + align:start position:0% +later and similarly during the turn on +we can also say that it will be the + + align:start position:0% +we can also say that it will be the + + + align:start position:0% +we can also say that it will be the +switch current increase first and when + + align:start position:0% +switch current increase first and when + + + align:start position:0% +switch current increase first and when +the switch current go to its maximum + + align:start position:0% +the switch current go to its maximum + + + align:start position:0% +the switch current go to its maximum +which is + + align:start position:0% +which is + + + align:start position:0% +which is +I and then the switch voltage will + + align:start position:0% +I and then the switch voltage will + + + align:start position:0% +I and then the switch voltage will +decrease and why is that is also because + + align:start position:0% +decrease and why is that is also because + + + align:start position:0% +decrease and why is that is also because +of the characteristics of this dial + + align:start position:0% +of the characteristics of this dial + + + align:start position:0% +of the characteristics of this dial +because the dial cannot be turned off or + + align:start position:0% +because the dial cannot be turned off or + + + align:start position:0% +because the dial cannot be turned off or +block voltage until it has zero current + + align:start position:0% +block voltage until it has zero current + + + align:start position:0% +block voltage until it has zero current +and to have the dial to have the zero + + align:start position:0% +and to have the dial to have the zero + + + align:start position:0% +and to have the dial to have the zero +current it means the isw should flow + + align:start position:0% +current it means the isw should flow + + + align:start position:0% +current it means the isw should flow +through all the load current and which + + align:start position:0% +through all the load current and which + + + align:start position:0% +through all the load current and which +means the load current should increase + + align:start position:0% +means the load current should increase + + + align:start position:0% +means the load current should increase +first and at this time the load the + + align:start position:0% +first and at this time the load the + + + align:start position:0% +first and at this time the load the +current in the dial will become zero and + + align:start position:0% +current in the dial will become zero and + + + align:start position:0% +current in the dial will become zero and +the dial can be turn off and block the + + align:start position:0% +the dial can be turn off and block the + + + align:start position:0% +the dial can be turn off and block the +voltage and once the dial blocks the + + align:start position:0% +voltage and once the dial blocks the + + + align:start position:0% +voltage and once the dial blocks the +voltage the vsw can decrease + + align:start position:0% + + + + align:start position:0% + +so this is the switching waveforms + + align:start position:0% +so this is the switching waveforms + + + align:start position:0% +so this is the switching waveforms +during the during for the switch during + + align:start position:0% +during the during for the switch during + + + align:start position:0% +during the during for the switch during +the turn on and turn off and usually we + + align:start position:0% +the turn on and turn off and usually we + + + align:start position:0% +the turn on and turn off and usually we +notate this time interval as the + + align:start position:0% +notate this time interval as the + + + align:start position:0% +notate this time interval as the +T4 during this turn off and we have the + + align:start position:0% +T4 during this turn off and we have the + + + align:start position:0% +T4 during this turn off and we have the +this time interval as t r during its + + align:start position:0% +this time interval as t r during its + + + align:start position:0% +this time interval as t r during its +turn + + align:start position:0% + + + + align:start position:0% + +on I mean for ideal switch + + align:start position:0% +on I mean for ideal switch + + + align:start position:0% +on I mean for ideal switch +because this will be zero and this will + + align:start position:0% +because this will be zero and this will + + + align:start position:0% +because this will be zero and this will +be zero the current and voltage will + + align:start position:0% +be zero the current and voltage will + + + align:start position:0% +be zero the current and voltage will +have no overlap so the ideal switch the + + align:start position:0% +have no overlap so the ideal switch the + + + align:start position:0% +have no overlap so the ideal switch the +switching loss will be zero but for + + align:start position:0% +switching loss will be zero but for + + + align:start position:0% +switching loss will be zero but for +practical switch because we have the TF + + align:start position:0% +practical switch because we have the TF + + + align:start position:0% +practical switch because we have the TF +and the TR and the switch current and + + align:start position:0% +and the TR and the switch current and + + + align:start position:0% +and the TR and the switch current and +the switch voltage will have some + + align:start position:0% +the switch voltage will have some + + + align:start position:0% +the switch voltage will have some +overlap so we will have some switching + + align:start position:0% +overlap so we will have some switching + + + align:start position:0% +overlap so we will have some switching +loss and what is loss loss is the kind + + align:start position:0% +loss and what is loss loss is the kind + + + align:start position:0% +loss and what is loss loss is the kind +of power so that will still be the + + align:start position:0% +of power so that will still be the + + + align:start position:0% +of power so that will still be the +voltage times the + + align:start position:0% +voltage times the + + + align:start position:0% +voltage times the +current so if we draw the power loss + + align:start position:0% +current so if we draw the power loss + + + align:start position:0% +current so if we draw the power loss +time + + align:start position:0% +time + + + align:start position:0% +time +curve that will be the P disapate equals + + align:start position:0% +curve that will be the P disapate equals + + + align:start position:0% +curve that will be the P disapate equals +the + + align:start position:0% +the + + + align:start position:0% +the +vsw time + + align:start position:0% +vsw time + + + align:start position:0% +vsw time +isw so during the time interval besides + + align:start position:0% +isw so during the time interval besides + + + align:start position:0% +isw so during the time interval besides +the TR and the TF it will become zero + + align:start position:0% +the TR and the TF it will become zero + + + align:start position:0% +the TR and the TF it will become zero +will become a pretty small number and + + align:start position:0% +will become a pretty small number and + + + align:start position:0% +will become a pretty small number and +during this the loss will be a + + align:start position:0% + + + + align:start position:0% + +triangular and similar for the T TR for + + align:start position:0% +triangular and similar for the T TR for + + + align:start position:0% +triangular and similar for the T TR for +the turn on it will also be a triangular + + align:start position:0% +the turn on it will also be a triangular + + + align:start position:0% +the turn on it will also be a triangular +it is just simply the switch voltage + + align:start position:0% +it is just simply the switch voltage + + + align:start position:0% +it is just simply the switch voltage +times the switch current and we will + + align:start position:0% +times the switch current and we will + + + align:start position:0% +times the switch current and we will +find this will be the switching loss and + + align:start position:0% +find this will be the switching loss and + + + align:start position:0% +find this will be the switching loss and +this part of area which is the power + + align:start position:0% +this part of area which is the power + + + align:start position:0% +this part of area which is the power +integrated by the time will be the + + align:start position:0% +integrated by the time will be the + + + align:start position:0% +integrated by the time will be the +energy so this area will be the turn off + + align:start position:0% +energy so this area will be the turn off + + + align:start position:0% +energy so this area will be the turn off +energy let's say e + + align:start position:0% +energy let's say e + + + align:start position:0% +energy let's say e +off and this area will be the turn on + + align:start position:0% +off and this area will be the turn on + + + align:start position:0% +off and this area will be the turn on +energy let's say the E + + align:start position:0% +energy let's say the E + + + align:start position:0% +energy let's say the E +on so that is like if we switch this + + align:start position:0% +on so that is like if we switch this + + + align:start position:0% +on so that is like if we switch this +device in one period we switch off and + + align:start position:0% +device in one period we switch off and + + + align:start position:0% +device in one period we switch off and +we switch on we will we will lose part + + align:start position:0% +we switch on we will we will lose part + + + align:start position:0% +we switch on we will we will lose part +of this energy and as we said like the + + align:start position:0% +of this energy and as we said like the + + + align:start position:0% +of this energy and as we said like the +switching our power converters they + + align:start position:0% +switching our power converters they + + + align:start position:0% +switching our power converters they +switch frequently there's a switching + + align:start position:0% +switch frequently there's a switching + + + align:start position:0% +switch frequently there's a switching +frequency definition so then when we + + align:start position:0% +frequency definition so then when we + + + align:start position:0% +frequency definition so then when we +think about the switching + + align:start position:0% +think about the switching + + + align:start position:0% +think about the switching +loss that will be this triangular area + + align:start position:0% +loss that will be this triangular area + + + align:start position:0% +loss that will be this triangular area +which will be the half TF times the v + + align:start position:0% +which will be the half TF times the v + + + align:start position:0% +which will be the half TF times the v +in times the I which is the turn off + + align:start position:0% +in times the I which is the turn off + + + align:start position:0% +in times the I which is the turn off +energy plus the turn on energy which is + + align:start position:0% +energy plus the turn on energy which is + + + align:start position:0% +energy plus the turn on energy which is +the time times the peak value V in times + + align:start position:0% +the time times the peak value V in times + + + align:start position:0% +the time times the peak value V in times +I and Times by The switching + + align:start position:0% +I and Times by The switching + + + align:start position:0% +I and Times by The switching +frequency that will be our switching + + align:start position:0% +frequency that will be our switching + + + align:start position:0% +frequency that will be our switching +loss and you can also consider like with + + align:start position:0% +loss and you can also consider like with + + + align:start position:0% +loss and you can also consider like with +times the switching frequency is + + align:start position:0% +times the switching frequency is + + + align:start position:0% +times the switching frequency is +equivalent to divided by the switching + + align:start position:0% +equivalent to divided by the switching + + + align:start position:0% +equivalent to divided by the switching +period And if you divide it by the + + align:start position:0% +period And if you divide it by the + + + align:start position:0% +period And if you divide it by the +switching period that will be an average + + align:start position:0% +switching period that will be an average + + + align:start position:0% +switching period that will be an average +power of it so it's still the same + + align:start position:0% +power of it so it's still the same + + + align:start position:0% +power of it so it's still the same +definition but you can look it in two + + align:start position:0% +definition but you can look it in two + + + align:start position:0% +definition but you can look it in two +aspect and also for the switching loss + + align:start position:0% +aspect and also for the switching loss + + + align:start position:0% +aspect and also for the switching loss +this is kind of killing us in our + + align:start position:0% +this is kind of killing us in our + + + align:start position:0% +this is kind of killing us in our +current converters so to to to decrease + + align:start position:0% +current converters so to to to decrease + + + align:start position:0% +current converters so to to to decrease +the switching loss we can decrease the + + align:start position:0% +the switching loss we can decrease the + + + align:start position:0% +the switching loss we can decrease the +switching frequency but however if we + + align:start position:0% +switching frequency but however if we + + + align:start position:0% +switching frequency but however if we +decreasing the switching frequency our + + align:start position:0% +decreasing the switching frequency our + + + align:start position:0% +decreasing the switching frequency our +passive component like the inductor or + + align:start position:0% +passive component like the inductor or + + + align:start position:0% +passive component like the inductor or +the capacitor will be very big so which + + align:start position:0% +the capacitor will be very big so which + + + align:start position:0% +the capacitor will be very big so which +limits our power density and our valve + + align:start position:0% +limits our power density and our valve + + + align:start position:0% +limits our power density and our valve +volume of our converter so we usually + + align:start position:0% +volume of our converter so we usually + + + align:start position:0% +volume of our converter so we usually +want to increase our switching frequency + + align:start position:0% +want to increase our switching frequency + + + align:start position:0% +want to increase our switching frequency +but the switching loss will limit us + + align:start position:0% +but the switching loss will limit us + + + align:start position:0% +but the switching loss will limit us +like how how large or how fast can we + + align:start position:0% +like how how large or how fast can we + + + align:start position:0% +like how how large or how fast can we +switch so another thing to minim to + + align:start position:0% +switch so another thing to minim to + + + align:start position:0% +switch so another thing to minim to +reduce the switching frequency is like + + align:start position:0% +reduce the switching frequency is like + + + align:start position:0% +reduce the switching frequency is like +can we decrease the TF or the TR or we + + align:start position:0% +can we decrease the TF or the TR or we + + + align:start position:0% +can we decrease the TF or the TR or we +decrease the turn on turn off energy or + + align:start position:0% +decrease the turn on turn off energy or + + + align:start position:0% +decrease the turn on turn off energy or +the turn on turn on energy so that comes + + align:start position:0% +the turn on turn on energy so that comes + + + align:start position:0% +the turn on turn on energy so that comes +with our + + align:start position:0% +with our + + + align:start position:0% +with our +snubber so before that let's have a demo + + align:start position:0% +snubber so before that let's have a demo + + + align:start position:0% +snubber so before that let's have a demo +of the switching lws so Rafa will do a + + align:start position:0% +of the switching lws so Rafa will do a + + + align:start position:0% +of the switching lws so Rafa will do a +demo and before we start the demo do you + + align:start position:0% +demo and before we start the demo do you + + + align:start position:0% +demo and before we start the demo do you +have any + + align:start position:0% +have any + + + align:start position:0% +have any +questions all right so I have a circuit + + align:start position:0% +questions all right so I have a circuit + + + align:start position:0% +questions all right so I have a circuit +here that's designed to help us look at + + align:start position:0% +here that's designed to help us look at + + + align:start position:0% +here that's designed to help us look at +the voltage and the current of a mosfet + + align:start position:0% +the voltage and the current of a mosfet + + + align:start position:0% +the voltage and the current of a mosfet +when we're turning it on or off so here + + align:start position:0% +when we're turning it on or off so here + + + align:start position:0% +when we're turning it on or off so here +you can see two + + align:start position:0% +you can see two + + + align:start position:0% +you can see two +transitions the parle or pink the pink W + + align:start position:0% +transitions the parle or pink the pink W + + + align:start position:0% +transitions the parle or pink the pink W +form is the voltage W form and the + + align:start position:0% +form is the voltage W form and the + + + align:start position:0% +form is the voltage W form and the +yellow W form is the current W form so + + align:start position:0% +yellow W form is the current W form so + + + align:start position:0% +yellow W form is the current W form so +on the + + align:start position:0% +on the + + + align:start position:0% +on the +left the yellow webform Rises and the + + align:start position:0% +left the yellow webform Rises and the + + + align:start position:0% +left the yellow webform Rises and the +voltage is falling which means there's + + align:start position:0% +voltage is falling which means there's + + + align:start position:0% +voltage is falling which means there's +no voltage across the switch and the + + align:start position:0% +no voltage across the switch and the + + + align:start position:0% +no voltage across the switch and the +switch turns on on the right the the + + align:start position:0% +switch turns on on the right the the + + + align:start position:0% +switch turns on on the right the the +current the yellow vform is falling and + + align:start position:0% +current the yellow vform is falling and + + + align:start position:0% +current the yellow vform is falling and +the pink webform is rising again which + + align:start position:0% +the pink webform is rising again which + + + align:start position:0% +the pink webform is rising again which +means the switch is turning off now let + + align:start position:0% +means the switch is turning off now let + + + align:start position:0% +means the switch is turning off now let +me zoom + + align:start position:0% +me zoom + + + align:start position:0% +me zoom +on in one + + align:start position:0% + + + + align:start position:0% + +transition let me zoom in on the turn on + + align:start position:0% +transition let me zoom in on the turn on + + + align:start position:0% +transition let me zoom in on the turn on +transition okay so as you can notice the + + align:start position:0% +transition okay so as you can notice the + + + align:start position:0% +transition okay so as you can notice the +yellow form is rising pretty quickly but + + align:start position:0% +yellow form is rising pretty quickly but + + + align:start position:0% +yellow form is rising pretty quickly but +the pink one which is a voltage War form + + align:start position:0% +the pink one which is a voltage War form + + + align:start position:0% +the pink one which is a voltage War form +takes some time time to completely hit + + align:start position:0% +takes some time time to completely hit + + + align:start position:0% +takes some time time to completely hit +zero which is the rise time and fall + + align:start position:0% +zero which is the rise time and fall + + + align:start position:0% +zero which is the rise time and fall +time Sheen was talking about and what + + align:start position:0% +time Sheen was talking about and what + + + align:start position:0% +time Sheen was talking about and what +will this do this means that there is a + + align:start position:0% +will this do this means that there is a + + + align:start position:0% +will this do this means that there is a +overlap time between the pink and the + + align:start position:0% +overlap time between the pink and the + + + align:start position:0% +overlap time between the pink and the +yellow we form Crossing and that's the + + align:start position:0% +yellow we form Crossing and that's the + + + align:start position:0% +yellow we form Crossing and that's the +overlap time creating the overlap loss + + align:start position:0% +overlap time creating the overlap loss + + + align:start position:0% +overlap time creating the overlap loss +now there's another sort of loss here + + align:start position:0% +now there's another sort of loss here + + + align:start position:0% +now there's another sort of loss here +notice when the switch is turning on the + + align:start position:0% +notice when the switch is turning on the + + + align:start position:0% +notice when the switch is turning on the +voltage is non zero which means if the + + align:start position:0% +voltage is non zero which means if the + + + align:start position:0% +voltage is non zero which means if the +switches capacitance is storing energy + + align:start position:0% +switches capacitance is storing energy + + + align:start position:0% +switches capacitance is storing energy +in it now let me also show you the power + + align:start position:0% +in it now let me also show you the power + + + align:start position:0% +in it now let me also show you the power +lws so you can see like the yellow Curve + + align:start position:0% +lws so you can see like the yellow Curve + + + align:start position:0% +lws so you can see like the yellow Curve +will be the current and the purple Curve + + align:start position:0% +will be the current and the purple Curve + + + align:start position:0% +will be the current and the purple Curve +will be the voltage and you can see that + + align:start position:0% +will be the voltage and you can see that + + + align:start position:0% +will be the voltage and you can see that +for hard switching it is the voltage + + align:start position:0% +for hard switching it is the voltage + + + align:start position:0% +for hard switching it is the voltage +increase first and then the current will + + align:start position:0% +increase first and then the current will + + + align:start position:0% +increase first and then the current will +decrease so which match with our Theory + + align:start position:0% +decrease so which match with our Theory + + + align:start position:0% +decrease so which match with our Theory +and you can also observe that for the + + align:start position:0% +and you can also observe that for the + + + align:start position:0% +and you can also observe that for the +yellow curve which we which is the + + align:start position:0% +yellow curve which we which is the + + + align:start position:0% +yellow curve which we which is the +voltage of sorry the the purple curve + + align:start position:0% +voltage of sorry the the purple curve + + + align:start position:0% +voltage of sorry the the purple curve +which is the voltage and during it onate + + align:start position:0% +which is the voltage and during it onate + + + align:start position:0% +which is the voltage and during it onate +it has a very small value so that will + + align:start position:0% +it has a very small value so that will + + + align:start position:0% +it has a very small value so that will +be the onate voltage drop it could be + + align:start position:0% +be the onate voltage drop it could be + + + align:start position:0% +be the onate voltage drop it could be +the RMS current times the + + align:start position:0% +the RMS current times the + + + align:start position:0% +the RMS current times the +rdsr yeah it's really hard to see but + + align:start position:0% +rdsr yeah it's really hard to see but + + + align:start position:0% +rdsr yeah it's really hard to see but +the purplish waveform the zigzag we form + + align:start position:0% +the purplish waveform the zigzag we form + + + align:start position:0% +the purplish waveform the zigzag we form +is the power loss you can also see that + + align:start position:0% +is the power loss you can also see that + + + align:start position:0% +is the power loss you can also see that +in here in the off State the line is + + align:start position:0% +in here in the off State the line is + + + align:start position:0% +in here in the off State the line is +pretty like almost zero because there's + + align:start position:0% +pretty like almost zero because there's + + + align:start position:0% +pretty like almost zero because there's +no voltage because there's no current in + + align:start position:0% +no voltage because there's no current in + + + align:start position:0% +no voltage because there's no current in +the switch in the other hand whenever + + align:start position:0% +the switch in the other hand whenever + + + align:start position:0% +the switch in the other hand whenever +you're seeing all those reps that's + + align:start position:0% +you're seeing all those reps that's + + + align:start position:0% +you're seeing all those reps that's +because when the switch is on it it acts + + align:start position:0% +because when the switch is on it it acts + + + align:start position:0% +because when the switch is on it it acts +like a resistor so it has some RDS on + + align:start position:0% +like a resistor so it has some RDS on + + + align:start position:0% +like a resistor so it has some RDS on +and nonzero current i sare r which makes + + align:start position:0% +and nonzero current i sare r which makes + + + align:start position:0% +and nonzero current i sare r which makes +the loss so now the mass shows the time + + align:start position:0% +the loss so now the mass shows the time + + + align:start position:0% +the loss so now the mass shows the time +of of the multiple of the voltage and + + align:start position:0% +of of the multiple of the voltage and + + + align:start position:0% +of of the multiple of the voltage and +the current and you can observe there's + + align:start position:0% +the current and you can observe there's + + + align:start position:0% +the current and you can observe there's +a triangular of that yeah so like we + + align:start position:0% +a triangular of that yeah so like we + + + align:start position:0% +a triangular of that yeah so like we +turn on and off our switch how many + + align:start position:0% +turn on and off our switch how many + + + align:start position:0% +turn on and off our switch how many +times 10 million times or 100,000 times + + align:start position:0% +times 10 million times or 100,000 times + + + align:start position:0% +times 10 million times or 100,000 times +per second it can seem trivial for one + + align:start position:0% +per second it can seem trivial for one + + + align:start position:0% +per second it can seem trivial for one +time but if we keep doing it this many + + align:start position:0% +time but if we keep doing it this many + + + align:start position:0% +time but if we keep doing it this many +times we cannot neglect this + + align:start position:0% +times we cannot neglect this + + + align:start position:0% +times we cannot neglect this +anymore thank you so another thing like + + align:start position:0% +anymore thank you so another thing like + + + align:start position:0% +anymore thank you so another thing like +I want to I'm not sure if You observe so + + align:start position:0% +I want to I'm not sure if You observe so + + + align:start position:0% +I want to I'm not sure if You observe so +during the switch turn off we do observe + + align:start position:0% +during the switch turn off we do observe + + + align:start position:0% +during the switch turn off we do observe +like the voltage they have some + + align:start position:0% +like the voltage they have some + + + align:start position:0% +like the voltage they have some +resonance here so this is because like + + align:start position:0% +resonance here so this is because like + + + align:start position:0% +resonance here so this is because like +as I said we want to decrease the TR and + + align:start position:0% +as I said we want to decrease the TR and + + + align:start position:0% +as I said we want to decrease the TR and +the TF but we have some limitations so + + align:start position:0% +the TF but we have some limitations so + + + align:start position:0% +the TF but we have some limitations so +the first limitations will be the + + align:start position:0% +the first limitations will be the + + + align:start position:0% +the first limitations will be the +parasitics so why so the parasitics is + + align:start position:0% +parasitics so why so the parasitics is + + + align:start position:0% +parasitics so why so the parasitics is +some unwanted parameters inside of the + + align:start position:0% +some unwanted parameters inside of the + + + align:start position:0% +some unwanted parameters inside of the +circuit so for example the parasitics + + align:start position:0% +circuit so for example the parasitics + + + align:start position:0% +circuit so for example the parasitics +could come from there maybe a parallel + + align:start position:0% +could come from there maybe a parallel + + + align:start position:0% +could come from there maybe a parallel +capacitance in parallel with the switch + + align:start position:0% +capacitance in parallel with the switch + + + align:start position:0% +capacitance in parallel with the switch +and for the and also there could be some + + align:start position:0% +and for the and also there could be some + + + align:start position:0% +and for the and also there could be some +straight inductance and when the switch + + align:start position:0% +straight inductance and when the switch + + + align:start position:0% +straight inductance and when the switch +is turn off this this parallel + + align:start position:0% +is turn off this this parallel + + + align:start position:0% +is turn off this this parallel +capacitance can resonate with this + + align:start position:0% +capacitance can resonate with this + + + align:start position:0% +capacitance can resonate with this +straight inductance and that will cause + + align:start position:0% +straight inductance and that will cause + + + align:start position:0% +straight inductance and that will cause +overshoot during the switch turn off and + + align:start position:0% +overshoot during the switch turn off and + + + align:start position:0% +overshoot during the switch turn off and +this overshoot can kill the switch so so + + align:start position:0% +this overshoot can kill the switch so so + + + align:start position:0% +this overshoot can kill the switch so so +this is one one one thing like we have + + align:start position:0% +this is one one one thing like we have + + + align:start position:0% +this is one one one thing like we have +the limitation for the TR and the TF and + + align:start position:0% +the limitation for the TR and the TF and + + + align:start position:0% +the limitation for the TR and the TF and +the second is is about the during the + + align:start position:0% +the second is is about the during the + + + align:start position:0% +the second is is about the during the +transient if we have very high if we + + align:start position:0% +transient if we have very high if we + + + align:start position:0% +transient if we have very high if we +have pretty low we have pretty small TF + + align:start position:0% +have pretty low we have pretty small TF + + + align:start position:0% +have pretty low we have pretty small TF +and TR our D DT or the DVT could be very + + align:start position:0% +and TR our D DT or the DVT could be very + + + align:start position:0% +and TR our D DT or the DVT could be very +large so what do I mean by the DT and DV + + align:start position:0% +large so what do I mean by the DT and DV + + + align:start position:0% +large so what do I mean by the DT and DV +DT so that will be the slope for the + + align:start position:0% +DT so that will be the slope for the + + + align:start position:0% +DT so that will be the slope for the +rising voltage or the falling current + + align:start position:0% +rising voltage or the falling current + + + align:start position:0% +rising voltage or the falling current +all the slope for the rising current and + + align:start position:0% +all the slope for the rising current and + + + align:start position:0% +all the slope for the rising current and +the falling voltage and this D DT and a + + align:start position:0% +the falling voltage and this D DT and a + + + align:start position:0% +the falling voltage and this D DT and a +dvdt they can have some carine inductor + + align:start position:0% +dvdt they can have some carine inductor + + + align:start position:0% +dvdt they can have some carine inductor +or caraline capacitor so imagine like if + + align:start position:0% +or caraline capacitor so imagine like if + + + align:start position:0% +or caraline capacitor so imagine like if +we have a caraline inductor which is L + + align:start position:0% +we have a caraline inductor which is L + + + align:start position:0% +we have a caraline inductor which is L +this ldt will cause some voltage and if + + align:start position:0% +this ldt will cause some voltage and if + + + align:start position:0% +this ldt will cause some voltage and if +we have a caring capacitor which is C + + align:start position:0% +we have a caring capacitor which is C + + + align:start position:0% +we have a caring capacitor which is C +this c dvdt will cause some current so + + align:start position:0% +this c dvdt will cause some current so + + + align:start position:0% +this c dvdt will cause some current so +previously if we have our DT or dvdt + + align:start position:0% +previously if we have our DT or dvdt + + + align:start position:0% +previously if we have our DT or dvdt +pretty small and our parasitics pretty + + align:start position:0% +pretty small and our parasitics pretty + + + align:start position:0% +pretty small and our parasitics pretty +small these things will not match our + + align:start position:0% +small these things will not match our + + + align:start position:0% +small these things will not match our +control circuit but either if we have a + + align:start position:0% +control circuit but either if we have a + + + align:start position:0% +control circuit but either if we have a +large inductance or a large capacitor + + align:start position:0% +large inductance or a large capacitor + + + align:start position:0% +large inductance or a large capacitor +together with a large DT or dvdt this + + align:start position:0% +together with a large DT or dvdt this + + + align:start position:0% +together with a large DT or dvdt this +voltage or current they are unexpected + + align:start position:0% +voltage or current they are unexpected + + + align:start position:0% +voltage or current they are unexpected +they can cause some errors for our + + align:start position:0% +they can cause some errors for our + + + align:start position:0% +they can cause some errors for our +control circuit so this is the second + + align:start position:0% +control circuit so this is the second + + + align:start position:0% +control circuit so this is the second +limitation and for the third limitation + + align:start position:0% +limitation and for the third limitation + + + align:start position:0% +limitation and for the third limitation +for the device itself we sometimes have + + align:start position:0% +for the device itself we sometimes have + + + align:start position:0% +for the device itself we sometimes have +the D DT or the + + align:start position:0% +the D DT or the + + + align:start position:0% +the D DT or the +dvdt requirement so the upper the second + + align:start position:0% +dvdt requirement so the upper the second + + + align:start position:0% +dvdt requirement so the upper the second +one is for the Emi issues but for this + + align:start position:0% +one is for the Emi issues but for this + + + align:start position:0% +one is for the Emi issues but for this +this is bad for the device itself it has + + align:start position:0% +this is bad for the device itself it has + + + align:start position:0% +this is bad for the device itself it has +nothing to do with the control circuits + + align:start position:0% +nothing to do with the control circuits + + + align:start position:0% +nothing to do with the control circuits +so so for example if we have a large + + align:start position:0% +so so for example if we have a large + + + align:start position:0% +so so for example if we have a large +current rating device let's say the igbt + + align:start position:0% +current rating device let's say the igbt + + + align:start position:0% +current rating device let's say the igbt +or the sccr if the DT is pretty if the + + align:start position:0% +or the sccr if the DT is pretty if the + + + align:start position:0% +or the sccr if the DT is pretty if the +DT is pretty large so in a short time + + align:start position:0% +DT is pretty large so in a short time + + + align:start position:0% +DT is pretty large so in a short time +the current cannot spread for the + + align:start position:0% +the current cannot spread for the + + + align:start position:0% +the current cannot spread for the +parallel die or the multiple wear bound + + align:start position:0% +parallel die or the multiple wear bound + + + align:start position:0% +parallel die or the multiple wear bound +so maybe one die or maybe one we Bond + + align:start position:0% +so maybe one die or maybe one we Bond + + + align:start position:0% +so maybe one die or maybe one we Bond +will blow up so that will destroy our + + align:start position:0% +will blow up so that will destroy our + + + align:start position:0% +will blow up so that will destroy our +device and for the DT if we have a high + + align:start position:0% +device and for the DT if we have a high + + + align:start position:0% +device and for the DT if we have a high +DT inside of the sirer it can trigger + + align:start position:0% +DT inside of the sirer it can trigger + + + align:start position:0% +DT inside of the sirer it can trigger +the syor back to on so usually we want + + align:start position:0% +the syor back to on so usually we want + + + align:start position:0% +the syor back to on so usually we want +to turn off the device but because of + + align:start position:0% +to turn off the device but because of + + + align:start position:0% +to turn off the device but because of +this High dvdt inside of the CER it can + + align:start position:0% +this High dvdt inside of the CER it can + + + align:start position:0% +this High dvdt inside of the CER it can +Tri trigger the CER back on so this is + + align:start position:0% +Tri trigger the CER back on so this is + + + align:start position:0% +Tri trigger the CER back on so this is +the third limitations for the TR and TF + + align:start position:0% +the third limitations for the TR and TF + + + align:start position:0% +the third limitations for the TR and TF +and usually the fourth one we said every + + align:start position:0% +and usually the fourth one we said every + + + align:start position:0% +and usually the fourth one we said every +device has a safe operating + + align:start position:0% +device has a safe operating + + + align:start position:0% +device has a safe operating +area so let's draw the vi curve of a + + align:start position:0% +area so let's draw the vi curve of a + + + align:start position:0% +area so let's draw the vi curve of a +device if this is V this is I so for + + align:start position:0% +device if this is V this is I so for + + + align:start position:0% +device if this is V this is I so for +normal device we have a maximum current + + align:start position:0% +normal device we have a maximum current + + + align:start position:0% +normal device we have a maximum current +rating and we also have a maximum off + + align:start position:0% +rating and we also have a maximum off + + + align:start position:0% +rating and we also have a maximum off +voltage rating but this is not like a + + align:start position:0% +voltage rating but this is not like a + + + align:start position:0% +voltage rating but this is not like a +square because we also have some power + + align:start position:0% +square because we also have some power + + + align:start position:0% +square because we also have some power +limitation or some Thal limitation so + + align:start position:0% +limitation or some Thal limitation so + + + align:start position:0% +limitation or some Thal limitation so +this this is a safe operating area for a + + align:start position:0% +this this is a safe operating area for a + + + align:start position:0% +this this is a safe operating area for a +device and we cannot have our switch + + align:start position:0% +device and we cannot have our switch + + + align:start position:0% +device and we cannot have our switch +voltage or switch current exceed this + + align:start position:0% +voltage or switch current exceed this + + + align:start position:0% +voltage or switch current exceed this +safe operating area for con for + + align:start position:0% +safe operating area for con for + + + align:start position:0% +safe operating area for con for +statistics operation or for a instaneous + + align:start position:0% +statistics operation or for a instaneous + + + align:start position:0% +statistics operation or for a instaneous +operation and here for the sers we care + + align:start position:0% +operation and here for the sers we care + + + align:start position:0% +operation and here for the sers we care +about the inous operation and the next + + align:start position:0% +about the inous operation and the next + + + align:start position:0% +about the inous operation and the next +lecture when we learn about the thermal + + align:start position:0% +lecture when we learn about the thermal + + + align:start position:0% +lecture when we learn about the thermal +we care about the static operation ation + + align:start position:0% +we care about the static operation ation + + + align:start position:0% +we care about the static operation ation +that is the RMS voltage or the RMS RMS + + align:start position:0% +that is the RMS voltage or the RMS RMS + + + align:start position:0% +that is the RMS voltage or the RMS RMS +current cannot exceed but here we C the + + align:start position:0% +current cannot exceed but here we C the + + + align:start position:0% +current cannot exceed but here we C the +inous one so if we think about this hard + + align:start position:0% +inous one so if we think about this hard + + + align:start position:0% +inous one so if we think about this hard +switching during the turn on and turn + + align:start position:0% +switching during the turn on and turn + + + align:start position:0% +switching during the turn on and turn +off let's say for during the turn + + align:start position:0% +off let's say for during the turn + + + align:start position:0% +off let's say for during the turn +off the the the current will hold + + align:start position:0% +off the the the current will hold + + + align:start position:0% +off the the the current will hold +constant until the voltage increase and + + align:start position:0% +constant until the voltage increase and + + + align:start position:0% +constant until the voltage increase and +then the current will drop and if it's a + + align:start position:0% +then the current will drop and if it's a + + + align:start position:0% +then the current will drop and if it's a +hard switching we can find that our + + align:start position:0% +hard switching we can find that our + + + align:start position:0% +hard switching we can find that our +inous current or voltage will exceed the + + align:start position:0% +inous current or voltage will exceed the + + + align:start position:0% +inous current or voltage will exceed the +safe op operating area and this is not + + align:start position:0% +safe op operating area and this is not + + + align:start position:0% +safe op operating area and this is not +good and this can destroy our device so + + align:start position:0% +good and this can destroy our device so + + + align:start position:0% +good and this can destroy our device so +that's why we want the snubber we want + + align:start position:0% +that's why we want the snubber we want + + + align:start position:0% +that's why we want the snubber we want +the snubber to manipulate with this + + align:start position:0% +the snubber to manipulate with this + + + align:start position:0% +the snubber to manipulate with this +switching locus of the iway curves and + + align:start position:0% +switching locus of the iway curves and + + + align:start position:0% +switching locus of the iway curves and +also for snubbers we want to decrease + + align:start position:0% +also for snubbers we want to decrease + + + align:start position:0% +also for snubbers we want to decrease +this turn off energy or the turn on + + align:start position:0% +this turn off energy or the turn on + + + align:start position:0% +this turn off energy or the turn on +energy of the switches inside of the + + align:start position:0% +energy of the switches inside of the + + + align:start position:0% +energy of the switches inside of the +switches so that's the motivation of our + + align:start position:0% +switches so that's the motivation of our + + + align:start position:0% +switches so that's the motivation of our +snabs so before we start snab do you + + align:start position:0% +snabs so before we start snab do you + + + align:start position:0% +snabs so before we start snab do you +have any + + align:start position:0% +have any + + + align:start position:0% +have any +questions cool + + align:start position:0% + + + + align:start position:0% + +so for Snappers we have two kind of + + align:start position:0% +so for Snappers we have two kind of + + + align:start position:0% +so for Snappers we have two kind of +motivation one is like we want to + + align:start position:0% +motivation one is like we want to + + + align:start position:0% +motivation one is like we want to +maintain the instantaneous current and + + align:start position:0% +maintain the instantaneous current and + + + align:start position:0% +maintain the instantaneous current and +voltage of the switch in the safe of + + align:start position:0% +voltage of the switch in the safe of + + + align:start position:0% +voltage of the switch in the safe of +operating area that is also like we want + + align:start position:0% +operating area that is also like we want + + + align:start position:0% +operating area that is also like we want +to have low DT or + + align:start position:0% + + + + align:start position:0% + +dvdt and the second motivation will be + + align:start position:0% +dvdt and the second motivation will be + + + align:start position:0% +dvdt and the second motivation will be +like we want to decrease the switching + + align:start position:0% +like we want to decrease the switching + + + align:start position:0% +like we want to decrease the switching +loss inside of the + + align:start position:0% +loss inside of the + + + align:start position:0% +loss inside of the +switches so please have attention what + + align:start position:0% +switches so please have attention what + + + align:start position:0% +switches so please have attention what +do I mean by the + + align:start position:0% + + + + align:start position:0% + +inside and now let's think about the + + align:start position:0% +inside and now let's think about the + + + align:start position:0% +inside and now let's think about the +turn off SN first so still we use this + + align:start position:0% +turn off SN first so still we use this + + + align:start position:0% +turn off SN first so still we use this +SP converter as our example we have the + + align:start position:0% +SP converter as our example we have the + + + align:start position:0% +SP converter as our example we have the +input voltage + + align:start position:0% +input voltage + + + align:start position:0% +input voltage +source and we have a MOS + + align:start position:0% +source and we have a MOS + + + align:start position:0% +source and we have a MOS +fat and we have a + + align:start position:0% +fat and we have a + + + align:start position:0% +fat and we have a +diode and this will be our constant load + + align:start position:0% +diode and this will be our constant load + + + align:start position:0% +diode and this will be our constant load +current + + align:start position:0% +current + + + align:start position:0% +current +source so previously at this terminal we + + align:start position:0% +source so previously at this terminal we + + + align:start position:0% +source so previously at this terminal we +said the diod cannot turn on or carry + + align:start position:0% +said the diod cannot turn on or carry + + + align:start position:0% +said the diod cannot turn on or carry +current until its voltage becomes + + align:start position:0% +current until its voltage becomes + + + align:start position:0% +current until its voltage becomes +zero but now we can have a capacitor + + align:start position:0% +zero but now we can have a capacitor + + + align:start position:0% +zero but now we can have a capacitor +that is in parallel with the switch and + + align:start position:0% +that is in parallel with the switch and + + + align:start position:0% +that is in parallel with the switch and +previously at this note we will have the + + align:start position:0% +previously at this note we will have the + + + align:start position:0% +previously at this note we will have the +KCl equation as I + + align:start position:0% +KCl equation as I + + + align:start position:0% +KCl equation as I +L is equal to ID plus the + + align:start position:0% +L is equal to ID plus the + + + align:start position:0% +L is equal to ID plus the +isw but now we have extra term which is + + align:start position:0% +isw but now we have extra term which is + + + align:start position:0% +isw but now we have extra term which is +the IC so the previously the D cannot + + align:start position:0% +the IC so the previously the D cannot + + + align:start position:0% +the IC so the previously the D cannot +conduct the current but now the + + align:start position:0% +conduct the current but now the + + + align:start position:0% +conduct the current but now the +capacitor can flow through the current + + align:start position:0% +capacitor can flow through the current + + + align:start position:0% +capacitor can flow through the current +and now we can have instantaneously the + + align:start position:0% +and now we can have instantaneously the + + + align:start position:0% +and now we can have instantaneously the +small voltage and current during the + + align:start position:0% +small voltage and current during the + + + align:start position:0% +small voltage and current during the +turn off at the same + + align:start position:0% + + + + align:start position:0% + +time so if we draw the iy + + align:start position:0% + + + + align:start position:0% + +curve for the switch current we still + + align:start position:0% +curve for the switch current we still + + + align:start position:0% +curve for the switch current we still +see like it will we still assume that + + align:start position:0% +see like it will we still assume that + + + align:start position:0% +see like it will we still assume that +will be a linear + + align:start position:0% + + + + align:start position:0% + +Transitions and when the switch current + + align:start position:0% +Transitions and when the switch current + + + align:start position:0% +Transitions and when the switch current +decrease from the IL + + align:start position:0% + + + + align:start position:0% + +the capacitor current can + + align:start position:0% + + + + align:start position:0% + +conduct and take and pay attention at at + + align:start position:0% +conduct and take and pay attention at at + + + align:start position:0% +conduct and take and pay attention at at +this time the ID the dial is still in + + align:start position:0% +this time the ID the dial is still in + + + align:start position:0% +this time the ID the dial is still in +the off + + align:start position:0% +the off + + + align:start position:0% +the off +State so when the switch has the linear + + align:start position:0% +State so when the switch has the linear + + + align:start position:0% +State so when the switch has the linear +ramp of the current the capacitor will + + align:start position:0% +ramp of the current the capacitor will + + + align:start position:0% +ramp of the current the capacitor will +similarly have the linear ramp of the + + align:start position:0% + + + + align:start position:0% + +current and at this this will be the I + + align:start position:0% + + + + align:start position:0% + +and for the capacitor voltage we know + + align:start position:0% + + + + align:start position:0% + +that this capacitor current will be c + + align:start position:0% +that this capacitor current will be c + + + align:start position:0% +that this capacitor current will be c +times the + + align:start position:0% +times the + + + align:start position:0% +times the +dvdt and correspondingly the voltage of + + align:start position:0% +dvdt and correspondingly the voltage of + + + align:start position:0% +dvdt and correspondingly the voltage of +a capacitor will be the integral of the + + align:start position:0% +a capacitor will be the integral of the + + + align:start position:0% +a capacitor will be the integral of the +capacitor + + align:start position:0% + + + + align:start position:0% + +current and here if we have a linear of + + align:start position:0% +current and here if we have a linear of + + + align:start position:0% +current and here if we have a linear of +the switch of the Capac current we will + + align:start position:0% +the switch of the Capac current we will + + + align:start position:0% +the switch of the Capac current we will +have the + + align:start position:0% +have the + + + align:start position:0% +have the +quadratic of the capacitor voltage and + + align:start position:0% +quadratic of the capacitor voltage and + + + align:start position:0% +quadratic of the capacitor voltage and +that capacitor voltage will be the + + align:start position:0% +that capacitor voltage will be the + + + align:start position:0% +that capacitor voltage will be the +switch voltage at the same + + align:start position:0% + + + + align:start position:0% + +time maybe I should change another + + align:start position:0% + + + + align:start position:0% + +color so if we if we draw it the + + align:start position:0% +color so if we if we draw it the + + + align:start position:0% +color so if we if we draw it the +waveform the this will be the Capac + + align:start position:0% +waveform the this will be the Capac + + + align:start position:0% +waveform the this will be the Capac +current if we draw the capacitor voltage + + align:start position:0% +current if we draw the capacitor voltage + + + align:start position:0% +current if we draw the capacitor voltage +because this is linear the integral of a + + align:start position:0% +because this is linear the integral of a + + + align:start position:0% +because this is linear the integral of a +linear will be + + align:start position:0% +linear will be + + + align:start position:0% +linear will be +quadratic so at this time the switch + + align:start position:0% +quadratic so at this time the switch + + + align:start position:0% +quadratic so at this time the switch +current will be off and after that the + + align:start position:0% +current will be off and after that the + + + align:start position:0% +current will be off and after that the +Capac current will fully conduct the + + align:start position:0% +Capac current will fully conduct the + + + align:start position:0% +Capac current will fully conduct the +load + + align:start position:0% +load + + + align:start position:0% +load +current and when the capacitor current + + align:start position:0% +current and when the capacitor current + + + align:start position:0% +current and when the capacitor current +is a constant the capacitor voltage will + + align:start position:0% +is a constant the capacitor voltage will + + + align:start position:0% +is a constant the capacitor voltage will +become + + align:start position:0% +become + + + align:start position:0% +become +linear but we don't care about this part + + align:start position:0% +linear but we don't care about this part + + + align:start position:0% +linear but we don't care about this part +anymore because we care the switching + + align:start position:0% +anymore because we care the switching + + + align:start position:0% +anymore because we care the switching +loss I mean for for this for this time + + align:start position:0% +loss I mean for for this for this time + + + align:start position:0% +loss I mean for for this for this time +we don't care we only C the switching + + align:start position:0% +we don't care we only C the switching + + + align:start position:0% +we don't care we only C the switching +current and voltage during this time + + align:start position:0% +current and voltage during this time + + + align:start position:0% +current and voltage during this time +interval from zero to + + align:start position:0% +interval from zero to + + + align:start position:0% +interval from zero to +TF so we only C the energy loss during + + align:start position:0% +TF so we only C the energy loss during + + + align:start position:0% +TF so we only C the energy loss during +this so actually we can have a + + align:start position:0% +this so actually we can have a + + + align:start position:0% +this so actually we can have a +calculation about this + + align:start position:0% +calculation about this + + + align:start position:0% +calculation about this +energy so let's see our switch current + + align:start position:0% +energy so let's see our switch current + + + align:start position:0% +energy so let's see our switch current +is + + align:start position:0% +is + + + align:start position:0% +is +i y minus t over + + align:start position:0% +i y minus t over + + + align:start position:0% +i y minus t over +TF and correspondingly our Capac current + + align:start position:0% +TF and correspondingly our Capac current + + + align:start position:0% +TF and correspondingly our Capac current +will be I time the T * + + align:start position:0% +will be I time the T * + + + align:start position:0% +will be I time the T * +TF and correspondingly our capacitor + + align:start position:0% +TF and correspondingly our capacitor + + + align:start position:0% +TF and correspondingly our capacitor +voltage or which is also the switch + + align:start position:0% +voltage or which is also the switch + + + align:start position:0% +voltage or which is also the switch +voltage will be the integral of + + align:start position:0% + + + + align:start position:0% + +this that will be the I times the t/ TF + + align:start position:0% +this that will be the I times the t/ TF + + + align:start position:0% +this that will be the I times the t/ TF +DT so that will be + + align:start position:0% +DT so that will be + + + align:start position:0% +DT so that will be +I TF * c t^ 2 so let me check if I do my + + align:start position:0% +I TF * c t^ 2 so let me check if I do my + + + align:start position:0% +I TF * c t^ 2 so let me check if I do my +algebra + + align:start position:0% +algebra + + + align:start position:0% +algebra +correct oh sorry so I should plug into + + align:start position:0% +correct oh sorry so I should plug into + + + align:start position:0% +correct oh sorry so I should plug into +the switch + + align:start position:0% + + + + align:start position:0% + +current oh sorry my bad this is + + align:start position:0% + + + + align:start position:0% + +correct so that will be i t^2 c * the TF + + align:start position:0% +correct so that will be i t^2 c * the TF + + + align:start position:0% +correct so that will be i t^2 c * the TF +so that will be the switch voltage + + align:start position:0% +so that will be the switch voltage + + + align:start position:0% +so that will be the switch voltage +expression and similarly if we calculate + + align:start position:0% +expression and similarly if we calculate + + + align:start position:0% +expression and similarly if we calculate +the switching + + align:start position:0% +the switching + + + align:start position:0% +the switching +loss what is loss loss is still a kind + + align:start position:0% +loss what is loss loss is still a kind + + + align:start position:0% +loss what is loss loss is still a kind +of power that will be the V switch times + + align:start position:0% +of power that will be the V switch times + + + align:start position:0% +of power that will be the V switch times +the I + + align:start position:0% +the I + + + align:start position:0% +the I +switch so we have the wi switch as this + + align:start position:0% +switch so we have the wi switch as this + + + align:start position:0% +switch so we have the wi switch as this +that will be I * t^2 over the capacitor + + align:start position:0% +that will be I * t^2 over the capacitor + + + align:start position:0% +that will be I * t^2 over the capacitor +value times the TF times the switch + + align:start position:0% +value times the TF times the switch + + + align:start position:0% +value times the TF times the switch +current which is this expression that + + align:start position:0% +current which is this expression that + + + align:start position:0% +current which is this expression that +will be the i y minus t/ + + align:start position:0% +will be the i y minus t/ + + + align:start position:0% +will be the i y minus t/ +TF so that will be the inous power + + align:start position:0% +TF so that will be the inous power + + + align:start position:0% +TF so that will be the inous power +expression and if we integrate this + + align:start position:0% +expression and if we integrate this + + + align:start position:0% +expression and if we integrate this +inous power we will have the turn off + + align:start position:0% +inous power we will have the turn off + + + align:start position:0% +inous power we will have the turn off +energy that is like we we integrate this + + align:start position:0% +energy that is like we we integrate this + + + align:start position:0% +energy that is like we we integrate this +PSW during the time interval from zero + + align:start position:0% +PSW during the time interval from zero + + + align:start position:0% +PSW during the time interval from zero +to the + + align:start position:0% +to the + + + align:start position:0% +to the +TF and if you do the algebra by yourself + + align:start position:0% +TF and if you do the algebra by yourself + + + align:start position:0% +TF and if you do the algebra by yourself +we will find the results + + align:start position:0% + + + + align:start position:0% + +of which is i s time the tf^ S over the + + align:start position:0% +of which is i s time the tf^ S over the + + + align:start position:0% +of which is i s time the tf^ S over the +24 times the + + align:start position:0% +24 times the + + + align:start position:0% +24 times the +capacitance so do you have any questions + + align:start position:0% +capacitance so do you have any questions + + + align:start position:0% +capacitance so do you have any questions +about this part yeah go + + align:start position:0% + + + + align:start position:0% + +ahead is that coming from + + align:start position:0% +ahead is that coming from + + + align:start position:0% +ahead is that coming from +that I or yeah so here we have + + align:start position:0% +that I or yeah so here we have + + + align:start position:0% +that I or yeah so here we have +assumption so even if we have a snubber + + align:start position:0% +assumption so even if we have a snubber + + + align:start position:0% +assumption so even if we have a snubber +we still assume the transit for the + + align:start position:0% +we still assume the transit for the + + + align:start position:0% +we still assume the transit for the +switch current is linear and we know + + align:start position:0% +switch current is linear and we know + + + align:start position:0% +switch current is linear and we know +that the current will decrease during + + align:start position:0% +that the current will decrease during + + + align:start position:0% +that the current will decrease during +the turn off so we have assumption like + + align:start position:0% +the turn off so we have assumption like + + + align:start position:0% +the turn off so we have assumption like +this will be a linear current so so + + align:start position:0% +this will be a linear current so so + + + align:start position:0% +this will be a linear current so so +that's why we have it start as a as a + + align:start position:0% +that's why we have it start as a as a + + + align:start position:0% +that's why we have it start as a as a +part and sure and previously because we + + align:start position:0% +part and sure and previously because we + + + align:start position:0% +part and sure and previously because we +don't have a another alternate path for + + align:start position:0% +don't have a another alternate path for + + + align:start position:0% +don't have a another alternate path for +current to flow so we need to wait until + + align:start position:0% +current to flow so we need to wait until + + + align:start position:0% +current to flow so we need to wait until +this ID yeah but ID is still zero at + + align:start position:0% +this ID yeah but ID is still zero at + + + align:start position:0% +this ID yeah but ID is still zero at +this time yeah + + align:start position:0% +this time yeah + + + align:start position:0% +this time yeah +cool so then we can calculate this turn + + align:start position:0% +cool so then we can calculate this turn + + + align:start position:0% +cool so then we can calculate this turn +off energy and what we can observe from + + align:start position:0% +off energy and what we can observe from + + + align:start position:0% +off energy and what we can observe from +this is like we can have a control + + align:start position:0% +this is like we can have a control + + + align:start position:0% +this is like we can have a control +handle which is our capacitance so if we + + align:start position:0% +handle which is our capacitance so if we + + + align:start position:0% +handle which is our capacitance so if we +want to decrease our turn off energy we + + align:start position:0% +want to decrease our turn off energy we + + + align:start position:0% +want to decrease our turn off energy we +can increase our capacitance value so we + + align:start position:0% +can increase our capacitance value so we + + + align:start position:0% +can increase our capacitance value so we +can do this however nothing is free we + + align:start position:0% +can do this however nothing is free we + + + align:start position:0% +can do this however nothing is free we +have to pay for + + align:start position:0% +have to pay for + + + align:start position:0% +have to pay for +something so imagine like if we have a + + align:start position:0% +something so imagine like if we have a + + + align:start position:0% +something so imagine like if we have a +capacitance in parallel with the switch + + align:start position:0% +capacitance in parallel with the switch + + + align:start position:0% +capacitance in parallel with the switch +every time during it when the switch is + + align:start position:0% +every time during it when the switch is + + + align:start position:0% +every time during it when the switch is +off we will store the energy inside of + + align:start position:0% +off we will store the energy inside of + + + align:start position:0% +off we will store the energy inside of +the capacitance that will be half CV + + align:start position:0% + + + + align:start position:0% + +squ so we we reduce the energy loss in + + align:start position:0% +squ so we we reduce the energy loss in + + + align:start position:0% +squ so we we reduce the energy loss in +the inside of the switch but outside the + + align:start position:0% +the inside of the switch but outside the + + + align:start position:0% +the inside of the switch but outside the +switch we we need to dissipate this part + + align:start position:0% +switch we we need to dissipate this part + + + align:start position:0% +switch we we need to dissipate this part +of energy so that what do I mean by we + + align:start position:0% +of energy so that what do I mean by we + + + align:start position:0% +of energy so that what do I mean by we +decrease the switching loss inside of + + align:start position:0% +decrease the switching loss inside of + + + align:start position:0% +decrease the switching loss inside of +the switches but we also have to pay for + + align:start position:0% +the switches but we also have to pay for + + + align:start position:0% +the switches but we also have to pay for +something that is the energy stored in + + align:start position:0% +something that is the energy stored in + + + align:start position:0% +something that is the energy stored in +this snubber capacitance so during the + + align:start position:0% +this snubber capacitance so during the + + + align:start position:0% +this snubber capacitance so during the +turn on if we do nothing this energy + + align:start position:0% +turn on if we do nothing this energy + + + align:start position:0% +turn on if we do nothing this energy +will be dumped into these switches so it + + align:start position:0% +will be dumped into these switches so it + + + align:start position:0% +will be dumped into these switches so it +will still lost and this part of energy + + align:start position:0% +will still lost and this part of energy + + + align:start position:0% +will still lost and this part of energy +could be very large it can still destroy + + align:start position:0% +could be very large it can still destroy + + + align:start position:0% +could be very large it can still destroy +our devices so this is not not a + + align:start position:0% +our devices so this is not not a + + + align:start position:0% +our devices so this is not not a +practical snubber as + + align:start position:0% +practical snubber as + + + align:start position:0% +practical snubber as +turn off SN so a practical one we need + + align:start position:0% +turn off SN so a practical one we need + + + align:start position:0% +turn off SN so a practical one we need +to do something else so let's still take + + align:start position:0% +to do something else so let's still take + + + align:start position:0% +to do something else so let's still take +this + + align:start position:0% +this + + + align:start position:0% +this +circuit we have the input + + align:start position:0% + + + + align:start position:0% + +voltage and we have the mostat we have + + align:start position:0% +voltage and we have the mostat we have + + + align:start position:0% +voltage and we have the mostat we have +the + + align:start position:0% +the + + + align:start position:0% +the +diod and we have the ideal current + + align:start position:0% +diod and we have the ideal current + + + align:start position:0% +diod and we have the ideal current +source so we kind of use two other + + align:start position:0% +source so we kind of use two other + + + align:start position:0% +source so we kind of use two other +component one is the diode in parallel + + align:start position:0% +component one is the diode in parallel + + + align:start position:0% +component one is the diode in parallel +with a + + align:start position:0% +with a + + + align:start position:0% +with a +resistor and then the in series with + + align:start position:0% +resistor and then the in series with + + + align:start position:0% +resistor and then the in series with +this + + align:start position:0% +this + + + align:start position:0% +this +capacitance so during it when we want to + + align:start position:0% +capacitance so during it when we want to + + + align:start position:0% +capacitance so during it when we want to +turn off the switch the current will + + align:start position:0% +turn off the switch the current will + + + align:start position:0% +turn off the switch the current will +still SL through this through this St + + align:start position:0% +still SL through this through this St + + + align:start position:0% +still SL through this through this St +and the capacitance and then when we + + align:start position:0% +and the capacitance and then when we + + + align:start position:0% +and the capacitance and then when we +want to turn on the switch so then + + align:start position:0% +want to turn on the switch so then + + + align:start position:0% +want to turn on the switch so then +because of we are charging this + + align:start position:0% +because of we are charging this + + + align:start position:0% +because of we are charging this +capacitor to the V this will be positive + + align:start position:0% +capacitor to the V this will be positive + + + align:start position:0% +capacitor to the V this will be positive +this will be negative and when we turn + + align:start position:0% +this will be negative and when we turn + + + align:start position:0% +this will be negative and when we turn +on the switch this capacitance will have + + align:start position:0% +on the switch this capacitance will have + + + align:start position:0% +on the switch this capacitance will have +a current pass through this resistor and + + align:start position:0% +a current pass through this resistor and + + + align:start position:0% +a current pass through this resistor and +through this m fat and we and most of + + align:start position:0% +through this m fat and we and most of + + + align:start position:0% +through this m fat and we and most of +the energy we can control we can dump it + + align:start position:0% +the energy we can control we can dump it + + + align:start position:0% +the energy we can control we can dump it +into this resistor instead of this m fat + + align:start position:0% +into this resistor instead of this m fat + + + align:start position:0% +into this resistor instead of this m fat +and also we can use this resistor to + + align:start position:0% +and also we can use this resistor to + + + align:start position:0% +and also we can use this resistor to +limits the current that flows through + + align:start position:0% +limits the current that flows through + + + align:start position:0% +limits the current that flows through +this m fat and in this way we are kind + + align:start position:0% +this m fat and in this way we are kind + + + align:start position:0% +this m fat and in this way we are kind +of solve we are kind of solve this part + + align:start position:0% +of solve we are kind of solve this part + + + align:start position:0% +of solve we are kind of solve this part +of energy that could destroy our device + + align:start position:0% +of energy that could destroy our device + + + align:start position:0% +of energy that could destroy our device +during the turn on but again we are not + + align:start position:0% +during the turn on but again we are not + + + align:start position:0% +during the turn on but again we are not +recover this part of energy this part of + + align:start position:0% +recover this part of energy this part of + + + align:start position:0% +recover this part of energy this part of +energy is still dissipated mostly on + + align:start position:0% +energy is still dissipated mostly on + + + align:start position:0% +energy is still dissipated mostly on +this resistor and the small part of + + align:start position:0% +this resistor and the small part of + + + align:start position:0% +this resistor and the small part of +amount in this fat but we can improve + + align:start position:0% +amount in this fat but we can improve + + + align:start position:0% +amount in this fat but we can improve +this so do you have any questions for a + + align:start position:0% +this so do you have any questions for a + + + align:start position:0% +this so do you have any questions for a +practical turn off + + align:start position:0% + + + + align:start position:0% + +SN okay so then let's go to the turn on + + align:start position:0% +SN okay so then let's go to the turn on + + + align:start position:0% +SN okay so then let's go to the turn on +S so the beauty of the circuit is that + + align:start position:0% +S so the beauty of the circuit is that + + + align:start position:0% +S so the beauty of the circuit is that +sometimes we can have a due Circuit of + + align:start position:0% +sometimes we can have a due Circuit of + + + align:start position:0% +sometimes we can have a due Circuit of +original circuit so a turn on S is the + + align:start position:0% +original circuit so a turn on S is the + + + align:start position:0% +original circuit so a turn on S is the +real the Dual Circuit of the turnoff s + + align:start position:0% +real the Dual Circuit of the turnoff s + + + align:start position:0% +real the Dual Circuit of the turnoff s +so let's draw the back converter again + + align:start position:0% +so let's draw the back converter again + + + align:start position:0% +so let's draw the back converter again +so we have a voltage source + + align:start position:0% +so we have a voltage source + + + align:start position:0% +so we have a voltage source +we have a + + align:start position:0% +we have a + + + align:start position:0% +we have a +transistor and we have a + + align:start position:0% +transistor and we have a + + + align:start position:0% +transistor and we have a +diode and we have the constant current + + align:start position:0% +diode and we have the constant current + + + align:start position:0% +diode and we have the constant current +load Source a load constant current load + + align:start position:0% +load Source a load constant current load + + + align:start position:0% +load Source a load constant current load +and now I insert a inductor in series + + align:start position:0% +and now I insert a inductor in series + + + align:start position:0% +and now I insert a inductor in series +with this + + align:start position:0% +with this + + + align:start position:0% +with this +transistor with with this m fat so + + align:start position:0% +transistor with with this m fat so + + + align:start position:0% +transistor with with this m fat so +previously we have the kvl equation + + align:start position:0% +previously we have the kvl equation + + + align:start position:0% +previously we have the kvl equation +which is + + align:start position:0% +which is + + + align:start position:0% +which is +V is equal to the + + align:start position:0% +V is equal to the + + + align:start position:0% +V is equal to the +vsw minus the + + align:start position:0% +vsw minus the + + + align:start position:0% +vsw minus the +VD and now we have a extra voltage extra + + align:start position:0% +VD and now we have a extra voltage extra + + + align:start position:0% +VD and now we have a extra voltage extra +components that can sustain the voltage + + align:start position:0% +components that can sustain the voltage + + + align:start position:0% +components that can sustain the voltage +which is + + align:start position:0% +which is + + + align:start position:0% +which is +VL so previously we are limited by the + + align:start position:0% +VL so previously we are limited by the + + + align:start position:0% +VL so previously we are limited by the +vi curve of this diode and now we have a + + align:start position:0% +vi curve of this diode and now we have a + + + align:start position:0% +vi curve of this diode and now we have a +second component to sustain this input + + align:start position:0% +second component to sustain this input + + + align:start position:0% +second component to sustain this input +voltage which means like when we turn on + + align:start position:0% +voltage which means like when we turn on + + + align:start position:0% +voltage which means like when we turn on +the switch we can have simultaneously + + align:start position:0% +the switch we can have simultaneously + + + align:start position:0% +the switch we can have simultaneously +small current and voltage at the same + + align:start position:0% +small current and voltage at the same + + + align:start position:0% +small current and voltage at the same +time we don't need to sustain the linear + + align:start position:0% +time we don't need to sustain the linear + + + align:start position:0% +time we don't need to sustain the linear +one during the overlap as a + + align:start position:0% +one during the overlap as a + + + align:start position:0% +one during the overlap as a +triangular so if we draw the + + align:start position:0% +triangular so if we draw the + + + align:start position:0% +triangular so if we draw the +waveform of the turn up + + align:start position:0% +waveform of the turn up + + + align:start position:0% +waveform of the turn up +that is still like we have the input we + + align:start position:0% +that is still like we have the input we + + + align:start position:0% +that is still like we have the input we +have the switch voltage which is I + + align:start position:0% +have the switch voltage which is I + + + align:start position:0% +have the switch voltage which is I +vsw they will have a linear decrease + + align:start position:0% +vsw they will have a linear decrease + + + align:start position:0% +vsw they will have a linear decrease +this is our + + align:start position:0% +this is our + + + align:start position:0% +this is our +assumption and also because we have a + + align:start position:0% +assumption and also because we have a + + + align:start position:0% +assumption and also because we have a +linear decrease of our switch voltage we + + align:start position:0% +linear decrease of our switch voltage we + + + align:start position:0% +linear decrease of our switch voltage we +will have a linear increase of our + + align:start position:0% +will have a linear increase of our + + + align:start position:0% +will have a linear increase of our +inductor + + align:start position:0% +inductor + + + align:start position:0% +inductor +voltage so the inductor voltage will + + align:start position:0% +voltage so the inductor voltage will + + + align:start position:0% +voltage so the inductor voltage will +increase + + align:start position:0% +increase + + + align:start position:0% +increase +linearly and the most basic equation for + + align:start position:0% +linearly and the most basic equation for + + + align:start position:0% +linearly and the most basic equation for +inductor that will be V L is LD + + align:start position:0% +inductor that will be V L is LD + + + align:start position:0% +inductor that will be V L is LD +DT so correspondingly if we want to find + + align:start position:0% +DT so correspondingly if we want to find + + + align:start position:0% +DT so correspondingly if we want to find +the inductor current we can just do the + + align:start position:0% +the inductor current we can just do the + + + align:start position:0% +the inductor current we can just do the +integral which is 1 / L time the v l * + + align:start position:0% +integral which is 1 / L time the v l * + + + align:start position:0% +integral which is 1 / L time the v l * +the DT so if we know that the inductor + + align:start position:0% +the DT so if we know that the inductor + + + align:start position:0% +the DT so if we know that the inductor +voltage will be a linear increase than + + align:start position:0% +voltage will be a linear increase than + + + align:start position:0% +voltage will be a linear increase than +the inductor current and if you pay + + align:start position:0% +the inductor current and if you pay + + + align:start position:0% +the inductor current and if you pay +attention this inductor current will be + + align:start position:0% +attention this inductor current will be + + + align:start position:0% +attention this inductor current will be +same as the switch current because they + + align:start position:0% +same as the switch current because they + + + align:start position:0% +same as the switch current because they +are in + + align:start position:0% +are in + + + align:start position:0% +are in +series and now this switch current will + + align:start position:0% +series and now this switch current will + + + align:start position:0% +series and now this switch current will +increase as + + align:start position:0% +increase as + + + align:start position:0% +increase as +quadratical and during this this is the + + align:start position:0% +quadratical and during this this is the + + + align:start position:0% +quadratical and during this this is the +quadratical of the switch + + align:start position:0% +quadratical of the switch + + + align:start position:0% +quadratical of the switch +current and after this TR the switch is + + align:start position:0% +current and after this TR the switch is + + + align:start position:0% +current and after this TR the switch is +fully on so the inductor + + align:start position:0% +fully on so the inductor + + + align:start position:0% +fully on so the inductor +current sorry the the the switch is + + align:start position:0% +current sorry the the the switch is + + + align:start position:0% +current sorry the the the switch is +fully on this will be zero and this is + + align:start position:0% +fully on this will be zero and this is + + + align:start position:0% +fully on this will be zero and this is +still zero and this VL will fully take + + align:start position:0% +still zero and this VL will fully take + + + align:start position:0% +still zero and this VL will fully take +the input voltage so this will be a + + align:start position:0% +the input voltage so this will be a + + + align:start position:0% +the input voltage so this will be a +constant value and if it's a constant + + align:start position:0% +constant value and if it's a constant + + + align:start position:0% +constant value and if it's a constant +value for inductor voltage then the + + align:start position:0% +value for inductor voltage then the + + + align:start position:0% +value for inductor voltage then the +current will be + + align:start position:0% + + + + align:start position:0% + +linear but again we don't carear this + + align:start position:0% +linear but again we don't carear this + + + align:start position:0% +linear but again we don't carear this +part for the switches because it is + + align:start position:0% +part for the switches because it is + + + align:start position:0% +part for the switches because it is +after the TR the switch has already + + align:start position:0% +after the TR the switch has already + + + align:start position:0% +after the TR the switch has already +passed the transient and we can still + + align:start position:0% +passed the transient and we can still + + + align:start position:0% +passed the transient and we can still +calculate what will be the ener turn on + + align:start position:0% +calculate what will be the ener turn on + + + align:start position:0% +calculate what will be the ener turn on +energy during this part and compared to + + align:start position:0% +energy during this part and compared to + + + align:start position:0% +energy during this part and compared to +the original hard switching we can see + + align:start position:0% +the original hard switching we can see + + + align:start position:0% +the original hard switching we can see +that we have we have small overlap at + + align:start position:0% +that we have we have small overlap at + + + align:start position:0% +that we have we have small overlap at +the same time for the high voltage and + + align:start position:0% +the same time for the high voltage and + + + align:start position:0% +the same time for the high voltage and +high current so we can improve the turn + + align:start position:0% +high current so we can improve the turn + + + align:start position:0% +high current so we can improve the turn +on energy during this and also the same + + align:start position:0% +on energy during this and also the same + + + align:start position:0% +on energy during this and also the same +problem will be we still store the + + align:start position:0% +problem will be we still store the + + + align:start position:0% +problem will be we still store the +energy that is half l i + + align:start position:0% +energy that is half l i + + + align:start position:0% +energy that is half l i +s in this inductor we need to disapate + + align:start position:0% +s in this inductor we need to disapate + + + align:start position:0% +s in this inductor we need to disapate +this part of energy somewhere and for a + + align:start position:0% +this part of energy somewhere and for a + + + align:start position:0% +this part of energy somewhere and for a +practical use we still have + + align:start position:0% +practical use we still have + + + align:start position:0% +practical use we still have +a resistor in series with a + + align:start position:0% +a resistor in series with a + + + align:start position:0% +a resistor in series with a +diode and during if we want to disapate + + align:start position:0% +diode and during if we want to disapate + + + align:start position:0% +diode and during if we want to disapate +the energy of this inductor we will have + + align:start position:0% +the energy of this inductor we will have + + + align:start position:0% +the energy of this inductor we will have +its current flow like this when the + + align:start position:0% +its current flow like this when the + + + align:start position:0% +its current flow like this when the +switch is turn off so that's the beauty + + align:start position:0% +switch is turn off so that's the beauty + + + align:start position:0% +switch is turn off so that's the beauty +of the circuit so for a for for a + + align:start position:0% +of the circuit so for a for for a + + + align:start position:0% +of the circuit so for a for for a +concept we need a turn off parallel + + align:start position:0% +concept we need a turn off parallel + + + align:start position:0% +concept we need a turn off parallel +capacitors and for the concept we need a + + align:start position:0% +capacitors and for the concept we need a + + + align:start position:0% +capacitors and for the concept we need a +series turn on inductor and for a more + + align:start position:0% +series turn on inductor and for a more + + + align:start position:0% +series turn on inductor and for a more +practical use we need a diod in parallel + + align:start position:0% +practical use we need a diod in parallel + + + align:start position:0% +practical use we need a diod in parallel +with the resistor then in series with + + align:start position:0% +with the resistor then in series with + + + align:start position:0% +with the resistor then in series with +this capacitor and for the Practical + + align:start position:0% +this capacitor and for the Practical + + + align:start position:0% +this capacitor and for the Practical +turnout number we need a DI in series + + align:start position:0% +turnout number we need a DI in series + + + align:start position:0% +turnout number we need a DI in series +with the resistor then in parallel with + + align:start position:0% +with the resistor then in parallel with + + + align:start position:0% +with the resistor then in parallel with +this inductor so this is the fully du of + + align:start position:0% +this inductor so this is the fully du of + + + align:start position:0% +this inductor so this is the fully du of +the circuit so this is a practical one + + align:start position:0% +the circuit so this is a practical one + + + align:start position:0% +the circuit so this is a practical one +of the Practical turn on SN and this is + + align:start position:0% +of the Practical turn on SN and this is + + + align:start position:0% +of the Practical turn on SN and this is +a practical turn off + + align:start position:0% +a practical turn off + + + align:start position:0% +a practical turn off +SN so do you have any + + align:start position:0% +SN so do you have any + + + align:start position:0% +SN so do you have any +questions yeah go ahead would you use + + align:start position:0% +questions yeah go ahead would you use + + + align:start position:0% +questions yeah go ahead would you use +both on yeah that's actually a very good + + align:start position:0% +both on yeah that's actually a very good + + + align:start position:0% +both on yeah that's actually a very good +question so this is only we care about + + align:start position:0% +question so this is only we care about + + + align:start position:0% +question so this is only we care about +the turn off this is what we care about + + align:start position:0% +the turn off this is what we care about + + + align:start position:0% +the turn off this is what we care about +the turn on so we and also again we + + align:start position:0% +the turn on so we and also again we + + + align:start position:0% +the turn on so we and also again we +justay this amount of energy fully so in + + align:start position:0% +justay this amount of energy fully so in + + + align:start position:0% +justay this amount of energy fully so in +the Practical we can design some + + align:start position:0% +the Practical we can design some + + + align:start position:0% +the Practical we can design some +Snappers that can both deal with a turn + + align:start position:0% +Snappers that can both deal with a turn + + + align:start position:0% +Snappers that can both deal with a turn +on and a turn off and we can imagine + + align:start position:0% +on and a turn off and we can imagine + + + align:start position:0% +on and a turn off and we can imagine +like some semiconductor devices we may + + align:start position:0% +like some semiconductor devices we may + + + align:start position:0% +like some semiconductor devices we may +care more about the turn on or we may + + align:start position:0% +care more about the turn on or we may + + + align:start position:0% +care more about the turn on or we may +care about the turn off so we can select + + align:start position:0% +care about the turn off so we can select + + + align:start position:0% +care about the turn off so we can select +a trade off like we want to mitigate the + + align:start position:0% +a trade off like we want to mitigate the + + + align:start position:0% +a trade off like we want to mitigate the +turn on loss more or we want to mitigate + + align:start position:0% +turn on loss more or we want to mitigate + + + align:start position:0% +turn on loss more or we want to mitigate +the turn off loss more and also here we + + align:start position:0% +the turn off loss more and also here we + + + align:start position:0% +the turn off loss more and also here we +are dissipated the energy of the half CV + + align:start position:0% +are dissipated the energy of the half CV + + + align:start position:0% +are dissipated the energy of the half CV +squ and the half Li squar in the + + align:start position:0% +squ and the half Li squar in the + + + align:start position:0% +squ and the half Li squar in the +Practical we can still design some + + align:start position:0% +Practical we can still design some + + + align:start position:0% +Practical we can still design some +recovery circuit we can recycle this + + align:start position:0% +recovery circuit we can recycle this + + + align:start position:0% +recovery circuit we can recycle this +part of energy yeah so what's your + + align:start position:0% +part of energy yeah so what's your + + + align:start position:0% +part of energy yeah so what's your +question um in the we have the right uh + + align:start position:0% +question um in the we have the right uh + + + align:start position:0% +question um in the we have the right uh +can you just mention what BD is doing + + align:start position:0% +can you just mention what BD is doing + + + align:start position:0% +can you just mention what BD is doing +during all that you mean this style yeah + + align:start position:0% +during all that you mean this style yeah + + + align:start position:0% +during all that you mean this style yeah +so after this when the let's see this is + + align:start position:0% +so after this when the let's see this is + + + align:start position:0% +so after this when the let's see this is +the inductor current yeah which also the + + align:start position:0% +the inductor current yeah which also the + + + align:start position:0% +the inductor current yeah which also the +switch current so when the switch + + align:start position:0% +switch current so when the switch + + + align:start position:0% +switch current so when the switch +current is go to the + + align:start position:0% +current is go to the + + + align:start position:0% +current is go to the +IL and also similar + + align:start position:0% +IL and also similar + + + align:start position:0% +IL and also similar +here when the capacitor voltage or the + + align:start position:0% +here when the capacitor voltage or the + + + align:start position:0% +here when the capacitor voltage or the +switch voltage is fully go to the + + align:start position:0% + + + + align:start position:0% + +V then the diod will make a roll in here + + align:start position:0% +V then the diod will make a roll in here + + + align:start position:0% +V then the diod will make a roll in here +that will be similar in this + + align:start position:0% +that will be similar in this + + + align:start position:0% +that will be similar in this +case yeah so the diode will play a role + + align:start position:0% +case yeah so the diode will play a role + + + align:start position:0% +case yeah so the diode will play a role +after this time + + align:start position:0% +after this time + + + align:start position:0% +after this time +interval why why is not changing all to + + align:start position:0% +interval why why is not changing all to + + + align:start position:0% +interval why why is not changing all to +the left that time oh that will be the + + align:start position:0% +the left that time oh that will be the + + + align:start position:0% +the left that time oh that will be the +same reason of this because we still + + align:start position:0% +same reason of this because we still + + + align:start position:0% +same reason of this because we still +assume this is the ideal diod so the + + align:start position:0% +assume this is the ideal diod so the + + + align:start position:0% +assume this is the ideal diod so the +diod cannot turn on or carry current + + align:start position:0% +diod cannot turn on or carry current + + + align:start position:0% +diod cannot turn on or carry current +until it has zero voltage drop and + + align:start position:0% +until it has zero voltage drop and + + + align:start position:0% +until it has zero voltage drop and +similarly a dial cannot turn off or + + align:start position:0% +similarly a dial cannot turn off or + + + align:start position:0% +similarly a dial cannot turn off or +block the voltage until the current + + align:start position:0% +block the voltage until the current + + + align:start position:0% +block the voltage until the current +becomes + + align:start position:0% +becomes + + + align:start position:0% +becomes +zero yeah + + align:start position:0% +zero yeah + + + align:start position:0% +zero yeah +cool so do you have any questions about + + align:start position:0% +cool so do you have any questions about + + + align:start position:0% +cool so do you have any questions about +those numers yeah go + + align:start position:0% +those numers yeah go + + + align:start position:0% +those numers yeah go +ahead + + align:start position:0% +ahead + + + align:start position:0% +ahead +fuor res worse yeah that's actually a + + align:start position:0% +fuor res worse yeah that's actually a + + + align:start position:0% +fuor res worse yeah that's actually a +very good question so let's say because + + align:start position:0% +very good question so let's say because + + + align:start position:0% +very good question so let's say because +we have a parallel we have a series + + align:start position:0% +we have a parallel we have a series + + + align:start position:0% +we have a parallel we have a series +inductance here and during some + + align:start position:0% +inductance here and during some + + + align:start position:0% +inductance here and during some +transient we we still have this parallel + + align:start position:0% +transient we we still have this parallel + + + align:start position:0% +transient we we still have this parallel +capacitance and for this di there also + + align:start position:0% +capacitance and for this di there also + + + align:start position:0% +capacitance and for this di there also +could be some parallel capacitors they + + align:start position:0% +could be some parallel capacitors they + + + align:start position:0% +could be some parallel capacitors they +still resonant that is something we + + align:start position:0% +still resonant that is something we + + + align:start position:0% +still resonant that is something we +cannot avoid so in the textbook there's + + align:start position:0% +cannot avoid so in the textbook there's + + + align:start position:0% +cannot avoid so in the textbook there's +a chapter talk about like how we choose + + align:start position:0% +a chapter talk about like how we choose + + + align:start position:0% +a chapter talk about like how we choose +this inductor value and how we choose + + align:start position:0% +this inductor value and how we choose + + + align:start position:0% +this inductor value and how we choose +this resistor value and similarly we + + align:start position:0% +this resistor value and similarly we + + + align:start position:0% +this resistor value and similarly we +still have the parasitic St inductance + + align:start position:0% +still have the parasitic St inductance + + + align:start position:0% +still have the parasitic St inductance +here and during some case this capacitor + + align:start position:0% +here and during some case this capacitor + + + align:start position:0% +here and during some case this capacitor +will still resonant with this so there + + align:start position:0% +will still resonant with this so there + + + align:start position:0% +will still resonant with this so there +are some this is something we cannot + + align:start position:0% +are some this is something we cannot + + + align:start position:0% +are some this is something we cannot +avoid but we can have some circuit or + + align:start position:0% +avoid but we can have some circuit or + + + align:start position:0% +avoid but we can have some circuit or +element like how we choose this + + align:start position:0% +element like how we choose this + + + align:start position:0% +element like how we choose this +capacitance and how we choose this + + align:start position:0% +capacitance and how we choose this + + + align:start position:0% +capacitance and how we choose this +resistor to improve this and also if you + + align:start position:0% +resistor to improve this and also if you + + + align:start position:0% +resistor to improve this and also if you +imagine a second order system so we can + + align:start position:0% +imagine a second order system so we can + + + align:start position:0% +imagine a second order system so we can +have critical damp we can have over damp + + align:start position:0% +have critical damp we can have over damp + + + align:start position:0% +have critical damp we can have over damp +or we can have under damp so we can + + align:start position:0% +or we can have under damp so we can + + + align:start position:0% +or we can have under damp so we can +select purposely put some small resistor + + align:start position:0% +select purposely put some small resistor + + + align:start position:0% +select purposely put some small resistor +to damping that out but this is + + align:start position:0% +to damping that out but this is + + + align:start position:0% +to damping that out but this is +something we need to pay off about that + + align:start position:0% +something we need to pay off about that + + + align:start position:0% +something we need to pay off about that +yeah that's actually a very good + + align:start position:0% +yeah that's actually a very good + + + align:start position:0% +yeah that's actually a very good +question and here I want to still + + align:start position:0% +question and here I want to still + + + align:start position:0% +question and here I want to still +mention about the Snapper is we improve + + align:start position:0% +mention about the Snapper is we improve + + + align:start position:0% +mention about the Snapper is we improve +the switching loss or the turn on and + + align:start position:0% +the switching loss or the turn on and + + + align:start position:0% +the switching loss or the turn on and +turn off energy inside of the switch + + align:start position:0% +turn off energy inside of the switch + + + align:start position:0% +turn off energy inside of the switch +itself but we lose energy + + align:start position:0% +itself but we lose energy + + + align:start position:0% +itself but we lose energy +here and we lose energy here and the + + align:start position:0% +here and we lose energy here and the + + + align:start position:0% +here and we lose energy here and the +total energy we lost may be even more + + align:start position:0% +total energy we lost may be even more + + + align:start position:0% +total energy we lost may be even more +but why we want to do this because we + + align:start position:0% +but why we want to do this because we + + + align:start position:0% +but why we want to do this because we +want to keep the switch every curves + + align:start position:0% +want to keep the switch every curves + + + align:start position:0% +want to keep the switch every curves +inside of the safe operating area we + + align:start position:0% +inside of the safe operating area we + + + align:start position:0% +inside of the safe operating area we +want to have a safe DT or dvdt so that's + + align:start position:0% +want to have a safe DT or dvdt so that's + + + align:start position:0% +want to have a safe DT or dvdt so that's +the motivation and as I said before like + + align:start position:0% +the motivation and as I said before like + + + align:start position:0% +the motivation and as I said before like +for the snubbers we use it for igbt we + + align:start position:0% +for the snubbers we use it for igbt we + + + align:start position:0% +for the snubbers we use it for igbt we +use it for CER we use it for the BJT and + + align:start position:0% +use it for CER we use it for the BJT and + + + align:start position:0% +use it for CER we use it for the BJT and +currently for the most fat we we + + align:start position:0% +currently for the most fat we we + + + align:start position:0% +currently for the most fat we we +generally don't use sber for most fat + + align:start position:0% +generally don't use sber for most fat + + + align:start position:0% +generally don't use sber for most fat +but from this we still introduce this + + align:start position:0% +but from this we still introduce this + + + align:start position:0% +but from this we still introduce this +part of the content because you can + + align:start position:0% +part of the content because you can + + + align:start position:0% +part of the content because you can +learn the beauty of a capacitor you can + + align:start position:0% +learn the beauty of a capacitor you can + + + align:start position:0% +learn the beauty of a capacitor you can +learn the beauty of a diode so the diode + + align:start position:0% +learn the beauty of a diode so the diode + + + align:start position:0% +learn the beauty of a diode so the diode +is only one directional device so you + + align:start position:0% +is only one directional device so you + + + align:start position:0% +is only one directional device so you +can imagine like for future when you + + align:start position:0% +can imagine like for future when you + + + align:start position:0% +can imagine like for future when you +design a circuit how to use the dial to + + align:start position:0% +design a circuit how to use the dial to + + + align:start position:0% +design a circuit how to use the dial to +control your current flow paths + + align:start position:0% +control your current flow paths + + + align:start position:0% +control your current flow paths +yeah so another thing I want to say + + align:start position:0% +yeah so another thing I want to say + + + align:start position:0% +yeah so another thing I want to say +because we still have some time is like + + align:start position:0% +because we still have some time is like + + + align:start position:0% +because we still have some time is like +I want to introduce F The Gate Drive + + align:start position:0% +I want to introduce F The Gate Drive + + + align:start position:0% +I want to introduce F The Gate Drive +as we said before for this TR and TF + + align:start position:0% +as we said before for this TR and TF + + + align:start position:0% +as we said before for this TR and TF +where is that + + align:start position:0% +where is that + + + align:start position:0% +where is that +yeah for this TF or TR what do they + + align:start position:0% +yeah for this TF or TR what do they + + + align:start position:0% +yeah for this TF or TR what do they +depend on they depend on the devices or + + align:start position:0% +depend on they depend on the devices or + + + align:start position:0% +depend on they depend on the devices or +they depend on the drivers so imagine + + align:start position:0% +they depend on the drivers so imagine + + + align:start position:0% +they depend on the drivers so imagine +like we have a huge or a big device it + + align:start position:0% +like we have a huge or a big device it + + + align:start position:0% +like we have a huge or a big device it +may takes longer time to finish the turn + + align:start position:0% +may takes longer time to finish the turn + + + align:start position:0% +may takes longer time to finish the turn +on and the turn off transient but if we + + align:start position:0% +on and the turn off transient but if we + + + align:start position:0% +on and the turn off transient but if we +have a powerful driver maybe we can + + align:start position:0% +have a powerful driver maybe we can + + + align:start position:0% +have a powerful driver maybe we can +reduce that time so I want to introduce + + align:start position:0% +reduce that time so I want to introduce + + + align:start position:0% +reduce that time so I want to introduce +a small bit of the G drive is like + + align:start position:0% +a small bit of the G drive is like + + + align:start position:0% +a small bit of the G drive is like +sometimes when we want to drive M + + align:start position:0% +sometimes when we want to drive M + + + align:start position:0% +sometimes when we want to drive M +fat so this is the voltage source which + + align:start position:0% +fat so this is the voltage source which + + + align:start position:0% +fat so this is the voltage source which +is a Gate Drive which is a gate drive so + + align:start position:0% +is a Gate Drive which is a gate drive so + + + align:start position:0% +is a Gate Drive which is a gate drive so +we can have different + + align:start position:0% +we can have different + + + align:start position:0% +we can have different +path to turn on and turn off of + + align:start position:0% +path to turn on and turn off of + + + align:start position:0% +path to turn on and turn off of +the to turn on and turn off of the most + + align:start position:0% +the to turn on and turn off of the most + + + align:start position:0% +the to turn on and turn off of the most +fat so during the turn on so we can + + align:start position:0% +fat so during the turn on so we can + + + align:start position:0% +fat so during the turn on so we can +select a relatively Bigg resistor to + + align:start position:0% +select a relatively Bigg resistor to + + + align:start position:0% +select a relatively Bigg resistor to +charge this capacitor for turn off we + + align:start position:0% +charge this capacitor for turn off we + + + align:start position:0% +charge this capacitor for turn off we +really want it to be fast so we can have + + align:start position:0% +really want it to be fast so we can have + + + align:start position:0% +really want it to be fast so we can have +a small resistor + + align:start position:0% + + + + align:start position:0% + +here so do do you have any further + + align:start position:0% +here so do do you have any further + + + align:start position:0% +here so do do you have any further +questions about today's + + align:start position:0% + + + + align:start position:0% + +lecture yeah we still have some + + align:start position:0% +lecture yeah we still have some + + + align:start position:0% +lecture yeah we still have some +time so if not so that will be end for + + align:start position:0% +time so if not so that will be end for + + + align:start position:0% +time so if not so that will be end for +today's lecture thank you \ No newline at end of file diff --git a/oEUo2faDJNA.txt b/oEUo2faDJNA.txt new file mode 100644 index 0000000000000000000000000000000000000000..9afe9ece75181e3519524dd156e446a0746d76c7 --- /dev/null +++ b/oEUo2faDJNA.txt @@ -0,0 +1,1979 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT OpenCourseWare continue to + + align:start position:0% +will help MIT OpenCourseWare continue to + + + align:start position:0% +will help MIT OpenCourseWare continue to +offer high quality educational resources + + align:start position:0% +offer high quality educational resources + + + align:start position:0% +offer high quality educational resources +for free + + align:start position:0% +for free + + + align:start position:0% +for free +to make a donation or to view additional + + align:start position:0% +to make a donation or to view additional + + + align:start position:0% +to make a donation or to view additional +materials from hundreds of MIT courses + + align:start position:0% +materials from hundreds of MIT courses + + + align:start position:0% +materials from hundreds of MIT courses +visit MIT opencourseware at ocw.mit.edu + + align:start position:0% + + + + align:start position:0% + +so my question is sort of twofold sort + + align:start position:0% +so my question is sort of twofold sort + + + align:start position:0% +so my question is sort of twofold sort +of goes back on it sort of goes back on + + align:start position:0% +of goes back on it sort of goes back on + + + align:start position:0% +of goes back on it sort of goes back on +some of other things we've discussed the + + align:start position:0% +some of other things we've discussed the + + + align:start position:0% +some of other things we've discussed the +recent elections so I've recently been + + align:start position:0% +recent elections so I've recently been + + + align:start position:0% +recent elections so I've recently been +following some of your stuff and there's + + align:start position:0% +following some of your stuff and there's + + + align:start position:0% +following some of your stuff and there's +evidence that suggests that you sort of + + align:start position:0% +evidence that suggests that you sort of + + + align:start position:0% +evidence that suggests that you sort of +predicted rise from the campaign about + + align:start position:0% +predicted rise from the campaign about + + + align:start position:0% +predicted rise from the campaign about +seven years ago and I'm sort of curious + + align:start position:0% +seven years ago and I'm sort of curious + + + align:start position:0% +seven years ago and I'm sort of curious +what what what was so different about + + align:start position:0% +what what what was so different about + + + align:start position:0% +what what what was so different about +this election I presume you've seen the + + align:start position:0% +this election I presume you've seen the + + + align:start position:0% +this election I presume you've seen the +rise of funny presidential candidates + + align:start position:0% +rise of funny presidential candidates + + + align:start position:0% +rise of funny presidential candidates +over the years and I'm sort of curious + + align:start position:0% +over the years and I'm sort of curious + + + align:start position:0% +over the years and I'm sort of curious +to understand what what sort of prompted + + align:start position:0% +to understand what what sort of prompted + + + align:start position:0% +to understand what what sort of prompted +that that speculation he's under my + + align:start position:0% +that that speculation he's under my + + + align:start position:0% +that that speculation he's under my +question sort of it's looking more so + + align:start position:0% +question sort of it's looking more so + + + align:start position:0% +question sort of it's looking more so +into the future so as we discussed + + align:start position:0% +into the future so as we discussed + + + align:start position:0% +into the future so as we discussed +America is probably more polarized and + + align:start position:0% +America is probably more polarized and + + + align:start position:0% +America is probably more polarized and +it's I guess sort of been in the past + + align:start position:0% +it's I guess sort of been in the past + + + align:start position:0% +it's I guess sort of been in the past +and there's sort of this idea that the + + align:start position:0% +and there's sort of this idea that the + + + align:start position:0% +and there's sort of this idea that the +clustering of like-minded Americans is + + align:start position:0% +clustering of like-minded Americans is + + + align:start position:0% +clustering of like-minded Americans is +tearing us apart + + align:start position:0% +tearing us apart + + + align:start position:0% +tearing us apart +so where do you see the future of this + + align:start position:0% +so where do you see the future of this + + + align:start position:0% +so where do you see the future of this +nation going + + align:start position:0% + + + + align:start position:0% + +well I mean there are many special + + align:start position:0% +well I mean there are many special + + + align:start position:0% +well I mean there are many special +factors in the United States societies + + align:start position:0% +factors in the United States societies + + + align:start position:0% +factors in the United States societies +are different but notice that what + + align:start position:0% +are different but notice that what + + + align:start position:0% +are different but notice that what +happened in this election what actually + + align:start position:0% +happened in this election what actually + + + align:start position:0% +happened in this election what actually +happened in the 2016 election is that + + align:start position:0% +happened in the 2016 election is that + + + align:start position:0% +happened in the 2016 election is that +the mainstream establishment + + align:start position:0% +the mainstream establishment + + + align:start position:0% +the mainstream establishment +institutions were basically destroyed + + align:start position:0% +institutions were basically destroyed + + + align:start position:0% +institutions were basically destroyed +the two major phenomena in this election + + align:start position:0% +the two major phenomena in this election + + + align:start position:0% +the two major phenomena in this election +where the Sanders campaign among the + + align:start position:0% +where the Sanders campaign among the + + + align:start position:0% +where the Sanders campaign among the +Democrats and the Trump campaign among + + align:start position:0% +Democrats and the Trump campaign among + + + align:start position:0% +Democrats and the Trump campaign among +the Republicans and they were both + + align:start position:0% +the Republicans and they were both + + + align:start position:0% +the Republicans and they were both +anti-establishment and the voters went + + align:start position:0% +anti-establishment and the voters went + + + align:start position:0% +anti-establishment and the voters went +that way the if you take a look at poll + + align:start position:0% +that way the if you take a look at poll + + + align:start position:0% +that way the if you take a look at poll +polling results you can see it I mean + + align:start position:0% +polling results you can see it I mean + + + align:start position:0% +polling results you can see it I mean +anger and contempt for institutions is + + align:start position:0% +anger and contempt for institutions is + + + align:start position:0% +anger and contempt for institutions is +just phenomenal you know you ask people + + align:start position:0% +just phenomenal you know you ask people + + + align:start position:0% +just phenomenal you know you ask people +and polls that they have any what do you + + align:start position:0% +and polls that they have any what do you + + + align:start position:0% +and polls that they have any what do you +think about Congress you know 90 percent + + align:start position:0% +think about Congress you know 90 percent + + + align:start position:0% +think about Congress you know 90 percent +say they have you all thrown out you + + align:start position:0% +say they have you all thrown out you + + + align:start position:0% +say they have you all thrown out you +know in fact about the only institution + + align:start position:0% +know in fact about the only institution + + + align:start position:0% +know in fact about the only institution +that has any respect is the military + + align:start position:0% +that has any respect is the military + + + align:start position:0% +that has any respect is the military +because you're taught you know somehow + + align:start position:0% +because you're taught you know somehow + + + align:start position:0% +because you're taught you know somehow +the military's defending us from those + + align:start position:0% +the military's defending us from those + + + align:start position:0% +the military's defending us from those +one but and the same is true in your + + align:start position:0% +one but and the same is true in your + + + align:start position:0% +one but and the same is true in your +take a look at the French election a + + align:start position:0% +take a look at the French election a + + + align:start position:0% +take a look at the French election a +couple days ago the two candidates were + + align:start position:0% +couple days ago the two candidates were + + + align:start position:0% +couple days ago the two candidates were +Outsiders the political parties barely + + align:start position:0% +Outsiders the political parties barely + + + align:start position:0% +Outsiders the political parties barely +participated knock on the pen are from + + align:start position:0% +participated knock on the pen are from + + + align:start position:0% +participated knock on the pen are from +outside the mainstream that has run + + align:start position:0% +outside the mainstream that has run + + + align:start position:0% +outside the mainstream that has run +Europe for 50 years the center right and + + align:start position:0% +Europe for 50 years the center right and + + + align:start position:0% +Europe for 50 years the center right and +center-left parties are gone same thing + + align:start position:0% +center-left parties are gone same thing + + + align:start position:0% +center-left parties are gone same thing +happened in England with brexit same + + align:start position:0% +happened in England with brexit same + + + align:start position:0% +happened in England with brexit same +things happening in other European + + align:start position:0% +things happening in other European + + + align:start position:0% +things happening in other European +countries we're seeing a phenomenon all + + align:start position:0% +countries we're seeing a phenomenon all + + + align:start position:0% +countries we're seeing a phenomenon all +over the world Western world in which + + align:start position:0% +over the world Western world in which + + + align:start position:0% +over the world Western world in which +the centrist you know center left center + + align:start position:0% +the centrist you know center left center + + + align:start position:0% +the centrist you know center left center +right institutions are under attack + + align:start position:0% +right institutions are under attack + + + align:start position:0% +right institutions are under attack +people are angry about them they hate + + align:start position:0% +people are angry about them they hate + + + align:start position:0% +people are angry about them they hate +them they think they're not working for + + align:start position:0% +them they think they're not working for + + + align:start position:0% +them they think they're not working for +us + + align:start position:0% +us + + + align:start position:0% +us +and they're right that's the effect of + + align:start position:0% +and they're right that's the effect of + + + align:start position:0% +and they're right that's the effect of +the neoliberal programs we're all + + align:start position:0% +the neoliberal programs we're all + + + align:start position:0% +the neoliberal programs we're all +subjected to the same socio-economic + + align:start position:0% +subjected to the same socio-economic + + + align:start position:0% +subjected to the same socio-economic +programs they've had a similar effect + + align:start position:0% +programs they've had a similar effect + + + align:start position:0% +programs they've had a similar effect +everywhere they've led to stagnation + + align:start position:0% +everywhere they've led to stagnation + + + align:start position:0% +everywhere they've led to stagnation +decline undermining of public services + + align:start position:0% +decline undermining of public services + + + align:start position:0% +decline undermining of public services +inability the Reagan slogan into the + + align:start position:0% +inability the Reagan slogan into the + + + align:start position:0% +inability the Reagan slogan into the +state is the problem not the solution + + align:start position:0% +state is the problem not the solution + + + align:start position:0% +state is the problem not the solution +let's turn it over to private tyrannies + + align:start position:0% +let's turn it over to private tyrannies + + + align:start position:0% +let's turn it over to private tyrannies +which make it worse that's happening + + align:start position:0% +which make it worse that's happening + + + align:start position:0% +which make it worse that's happening +bits and pieces that are happening + + align:start position:0% +bits and pieces that are happening + + + align:start position:0% +bits and pieces that are happening +everywhere so it happened in the United + + align:start position:0% +everywhere so it happened in the United + + + align:start position:0% +everywhere so it happened in the United +States and its own particular way but + + align:start position:0% +States and its own particular way but + + + align:start position:0% +States and its own particular way but +but notice that it's two directions + + align:start position:0% +but notice that it's two directions + + + align:start position:0% +but notice that it's two directions +it's Sanders and Trump and I think in + + align:start position:0% +it's Sanders and Trump and I think in + + + align:start position:0% +it's Sanders and Trump and I think in +many ways they were appealing to the + + align:start position:0% +many ways they were appealing to the + + + align:start position:0% +many ways they were appealing to the +same sentiments and they could even + + align:start position:0% +same sentiments and they could even + + + align:start position:0% +same sentiments and they could even +converge you know a lot of the poppy if + + align:start position:0% +converge you know a lot of the poppy if + + + align:start position:0% +converge you know a lot of the poppy if +you if you look at what people believe + + align:start position:0% +you if you look at what people believe + + + align:start position:0% +you if you look at what people believe +the policies that they 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majority of the population +thinks they're out of the national + + align:start position:0% +thinks they're out of the national + + + align:start position:0% +thinks they're out of the national +health care no in fact I support for + + align:start position:0% +health care no in fact I support for + + + align:start position:0% +health care no in fact I support for +nationally guaranteed self health care + + align:start position:0% +nationally guaranteed self health care + + + align:start position:0% +nationally guaranteed self health care +has been so high over the years that + + align:start position:0% +has been so high over the years that + + + align:start position:0% +has been so high over the years that +sometimes it's almost hard to believe so + + align:start position:0% +sometimes it's almost hard to believe so + + + align:start position:0% +sometimes it's almost hard to believe so +in the late Reagan years for example + + align:start position:0% +in the late Reagan years for example + + + align:start position:0% +in the late Reagan years for example +about seventy percent of the population + + align:start position:0% +about seventy percent of the population + + + align:start position:0% +about seventy percent of the population +I thought that guaranteed national + + align:start position:0% +I thought that guaranteed national + + + align:start position:0% +I thought that guaranteed national +health care ought to be in the + + align:start position:0% +health care ought to be in the + + + align:start position:0% +health care ought to be in the +Constitution because this is an obvious + + align:start position:0% +Constitution because this is an obvious + + + align:start position:0% +Constitution because this is an obvious +demands about 40% of the population + + align:start position:0% +demands about 40% of the population + + + align:start position:0% +demands about 40% of the population +thought it already was in the + + align:start position:0% +thought it already was in the + + + align:start position:0% +thought it already was in the +Constitution nobody knows what's in the + + align:start position:0% +Constitution nobody knows what's in the + + + align:start position:0% +Constitution nobody knows what's in the +Constitution just everything good must + + align:start position:0% +Constitution just everything good must + + + align:start position:0% +Constitution just everything good must +be in the Constitution since this is so + + align:start position:0% +be in the Constitution since this is so + + + align:start position:0% +be in the Constitution since this is so +obviously good it must be in the + + align:start position:0% +obviously good it must be in the + + + align:start position:0% +obviously good it must be in the +Constitution there's right at the + + align:start position:0% +Constitution there's right at the + + + align:start position:0% +Constitution there's right at the +present of the most recent polls show + + align:start position:0% +present of the most recent polls show + + + align:start position:0% +present of the most recent polls show +someone over fifty percent supporting a + + align:start position:0% +someone over fifty percent supporting a + + + align:start position:0% +someone over fifty percent supporting a +nice + + align:start position:0% +nice + + + align:start position:0% +nice +health care when Obama's Affordable Care + + align:start position:0% +health care when Obama's Affordable Care + + + align:start position:0% +health care when Obama's Affordable Care +Act was being pushed through at first + + align:start position:0% +Act was being pushed through at first + + + align:start position:0% +Act was being pushed through at first +there was one of the proposals one of + + align:start position:0% +there was one of the proposals one of + + + align:start position:0% +there was one of the proposals one of +the parts of it was what was called a + + align:start position:0% +the parts of it was what was called a + + + align:start position:0% +the parts of it was what was called a +public option which means you could + + align:start position:0% +public option which means you could + + + align:start position:0% +public option which means you could +choose if you wanted to be part of a + + align:start position:0% +choose if you wanted to be part of a + + + align:start position:0% +choose if you wanted to be part of a +government health care program about + + align:start position:0% +government health care program about + + + align:start position:0% +government health care program about +two-thirds of the population favored + + align:start position:0% +two-thirds of the population favored + + + align:start position:0% +two-thirds of the population favored +that but it was just thrown out without + + align:start position:0% +that but it was just thrown out without + + + align:start position:0% +that but it was just thrown out without +discussion the and in fact Fito + + align:start position:0% +discussion the and in fact Fito + + + align:start position:0% +discussion the and in fact Fito +case-by-case there's a lot of similarity + + align:start position:0% +case-by-case there's a lot of similarity + + + align:start position:0% +case-by-case there's a lot of similarity +in the attitudes about social political + + align:start position:0% +in the attitudes about social political + + + align:start position:0% +in the attitudes about social political +issues not necessarily cultural issues + + align:start position:0% +issues not necessarily cultural issues + + + align:start position:0% +issues not necessarily cultural issues +but social political issues among parts + + align:start position:0% +but social political issues among parts + + + align:start position:0% +but social political issues among parts +of the population that appear to be + + align:start position:0% +of the population that appear to be + + + align:start position:0% +of the population that appear to be +extremely polarized it's very + + align:start position:0% +extremely polarized it's very + + + align:start position:0% +extremely polarized it's very +interesting in England right now if he + + align:start position:0% +interesting in England right now if he + + + align:start position:0% +interesting in England right now if he +followed the Jeremy Corbyn has kind of a + + align:start position:0% +followed the Jeremy Corbyn has kind of a + + + align:start position:0% +followed the Jeremy Corbyn has kind of a +little bit like Sanders is bitterly + + align:start position:0% +little bit like Sanders is bitterly + + + align:start position:0% +little bit like Sanders is bitterly +attacked by the media I mean just + + align:start position:0% +attacked by the media I mean just + + + align:start position:0% +attacked by the media I mean just +including the liberal media like The + + align:start position:0% +including the liberal media like The + + + align:start position:0% +including the liberal media like The +Guardian and by the parliamentary Labour + + align:start position:0% +Guardian and by the parliamentary Labour + + + align:start position:0% +Guardian and by the parliamentary Labour +Party meaning the you know the guys who + + align:start position:0% +Party meaning the you know the guys who + + + align:start position:0% +Party meaning the you know the guys who +sort of the elites who run the party + + align:start position:0% +sort of the elites who run the party + + + align:start position:0% +sort of the elites who run the party +among they just came out with a I + + align:start position:0% +among they just came out with a I + + + align:start position:0% +among they just came out with a I +happened to be in England a couple days + + align:start position:0% +happened to be in England a couple days + + + align:start position:0% +happened to be in England a couple days +ago as I was reading the British press + + align:start position:0% +ago as I was reading the British press + + + align:start position:0% +ago as I was reading the British press +they they just came out with their the + + align:start position:0% +they they just came out with their the + + + align:start position:0% +they they just came out with their the +Labour Party with their program which + + align:start position:0% +Labour Party with their program which + + + align:start position:0% +Labour Party with their program which +was just lambaste it by the media you + + align:start position:0% +was just lambaste it by the media you + + + align:start position:0% +was just lambaste it by the media you +know crazy lunatic insane it'll destroy + + align:start position:0% +know crazy lunatic insane it'll destroy + + + align:start position:0% +know crazy lunatic insane it'll destroy +the Labour Party at the same time polls + + align:start position:0% +the Labour Party at the same time polls + + + align:start position:0% +the Labour Party at the same time polls +came out asking people it was + + align:start position:0% +came out asking people it was + + + align:start position:0% +came out asking people it was +independent about the the components of + + align:start position:0% +independent about the the components of + + + align:start position:0% +independent about the the components of +the program they were all very popular + + align:start position:0% +the program they were all very popular + + + align:start position:0% +the program they were all very popular +very strong support among the population + + align:start position:0% +very strong support among the population + + + align:start position:0% +very strong support among the population +for the elements of the program but + + align:start position:0% +for the elements of the program but + + + align:start position:0% +for the elements of the program but +attack and on the party that's proposing + + align:start position:0% +attack and on the party that's proposing + + + align:start position:0% +attack and on the party that's proposing +them in a particular on cordovan these + + align:start position:0% +them in a particular on cordovan these + + + align:start position:0% +them in a particular on cordovan these +are you know the serious activism and + + align:start position:0% +are you know the serious activism and + + + align:start position:0% +are you know the serious activism and +organizing could overcome this I mean + + align:start position:0% +organizing could overcome this I mean + + + align:start position:0% +organizing could overcome this I mean +you're fighting a link elements who have + + align:start position:0% +you're fighting a link elements who have + + + align:start position:0% +you're fighting a link elements who have +their own + + align:start position:0% +their own + + + align:start position:0% +their own +image of the way they want society to go + + align:start position:0% +image of the way they want society to go + + + align:start position:0% +image of the way they want society to go +and in fact you know there's quite a lot + + align:start position:0% +and in fact you know there's quite a lot + + + align:start position:0% +and in fact you know there's quite a lot +of interesting things going on a lot of + + align:start position:0% +of interesting things going on a lot of + + + align:start position:0% +of interesting things going on a lot of +it has this stuff that you guys might be + + align:start position:0% +it has this stuff that you guys might be + + + align:start position:0% +it has this stuff that you guys might be +interested in has to do with data are + + align:start position:0% +interested in has to do with data are + + + align:start position:0% +interested in has to do with data are +vestee there's a company called + + align:start position:0% +vestee there's a company called + + + align:start position:0% +vestee there's a company called +Cambridge analytics I think which is run + + align:start position:0% +Cambridge analytics I think which is run + + + align:start position:0% +Cambridge analytics I think which is run +by some ultra-right billionaires Peter + + align:start position:0% +by some ultra-right billionaires Peter + + + align:start position:0% +by some ultra-right billionaires Peter +Thiel the guy who owns PayPal and a + + align:start position:0% +Thiel the guy who owns PayPal and a + + + align:start position:0% +Thiel the guy who owns PayPal and a +bunch of other things Robert Mercer + + align:start position:0% +bunch of other things Robert Mercer + + + align:start position:0% +bunch of other things Robert Mercer +who's a hedge fund manager multi + + align:start position:0% +who's a hedge fund manager multi + + + align:start position:0% +who's a hedge fund manager multi +billionaire a couple of others what + + align:start position:0% +billionaire a couple of others what + + + align:start position:0% +billionaire a couple of others what +they've been doing and this essentially + + align:start position:0% +they've been doing and this essentially + + + align:start position:0% +they've been doing and this essentially +gave the election to Trump is extremely + + align:start position:0% +gave the election to Trump is extremely + + + align:start position:0% +gave the election to Trump is extremely +careful data analysis there's a ton of + + align:start position:0% +careful data analysis there's a ton of + + + align:start position:0% +careful data analysis there's a ton of +data now from Facebook and other things + + align:start position:0% +data now from Facebook and other things + + + align:start position:0% +data now from Facebook and other things +about people's personal preferences and + + align:start position:0% +about people's personal preferences and + + + align:start position:0% +about people's personal preferences and +attitudes and you know feelings and are + + align:start position:0% +attitudes and you know feelings and are + + + align:start position:0% +attitudes and you know feelings and are +you depressed you know all kinds of + + align:start position:0% +you depressed you know all kinds of + + + align:start position:0% +you depressed you know all kinds of +things and what they're doing is looking + + align:start position:0% +things and what they're doing is looking + + + align:start position:0% +things and what they're doing is looking +carefully at this data and analyzing it + + align:start position:0% +carefully at this data and analyzing it + + + align:start position:0% +carefully at this data and analyzing it +to see if you can find small numbers of + + align:start position:0% +to see if you can find small numbers of + + + align:start position:0% +to see if you can find small numbers of +people in particular areas who can be + + align:start position:0% +people in particular areas who can be + + + align:start position:0% +people in particular areas who can be +who are vulnerable to one or another + + align:start position:0% +who are vulnerable to one or another + + + align:start position:0% +who are vulnerable to one or another +form of manipulation and what they're + + align:start position:0% +form of manipulation and what they're + + + align:start position:0% +form of manipulation and what they're +doing is trying to say look if they're + + align:start position:0% +doing is trying to say look if they're + + + align:start position:0% +doing is trying to say look if they're +kind of tend to be liberal try to get + + align:start position:0% +kind of tend to be liberal try to get + + + align:start position:0% +kind of tend to be liberal try to get +them to get so disillusioned that they + + align:start position:0% +them to get so disillusioned that they + + + align:start position:0% +them to get so disillusioned that they +won't vote and if they tend to be say + + align:start position:0% +won't vote and if they tend to be say + + + align:start position:0% +won't vote and if they tend to be say +traditionally conservative maybe + + align:start position:0% +traditionally conservative maybe + + + align:start position:0% +traditionally conservative maybe +religious or whatever I try to get them + + align:start position:0% +religious or whatever I try to get them + + + align:start position:0% +religious or whatever I try to get them +to do you know reach them individually + + align:start position:0% +to do you know reach them individually + + + align:start position:0% +to do you know reach them individually +in ways which will increase the + + align:start position:0% +in ways which will increase the + + + align:start position:0% +in ways which will increase the +probability that they'll vote for the + + align:start position:0% +probability that they'll vote for the + + + align:start position:0% +probability that they'll vote for the +right-wing this has small effects but + + align:start position:0% +right-wing this has small effects but + + + align:start position:0% +right-wing this has small effects but +the elections are won on very small + + align:start position:0% +the elections are won on very small + + + align:start position:0% +the elections are won on very small +effects like Trump's as you know Trump + + align:start position:0% +effects like Trump's as you know Trump + + + align:start position:0% +effects like Trump's as you know Trump +lost the popular vote but by a couple of + + align:start position:0% +lost the popular vote but by a couple of + + + align:start position:0% +lost the popular vote but by a couple of +million but in particular counties that + + align:start position:0% +million but in particular counties that + + + align:start position:0% +million but in particular counties that +made the difference a couple of hundred + + align:start position:0% +made the difference a couple of hundred + + + align:start position:0% +made the difference a couple of hundred +thousand votes shifted the election in + + align:start position:0% +thousand votes shifted the election in + + + align:start position:0% +thousand votes shifted the election in +England brexit was the same + + align:start position:0% +England brexit was the same + + + align:start position:0% +England brexit was the same +tomatoe about maybe 600,000 votes in all + + align:start position:0% +tomatoe about maybe 600,000 votes in all + + + align:start position:0% +tomatoe about maybe 600,000 votes in all +countries this week you know these + + align:start position:0% +countries this week you know these + + + align:start position:0% +countries this week you know these +companies using a lot of complicated + + align:start position:0% +companies using a lot of complicated + + + align:start position:0% +companies using a lot of complicated +data processing and statistics and so on + + align:start position:0% +data processing and statistics and so on + + + align:start position:0% +data processing and statistics and so on +working on ways to try to control the + + align:start position:0% +working on ways to try to control the + + + align:start position:0% +working on ways to try to control the +electoral process I mean this is way + + align:start position:0% +electoral process I mean this is way + + + align:start position:0% +electoral process I mean this is way +more important than any of the nonsense + + align:start position:0% +more important than any of the nonsense + + + align:start position:0% +more important than any of the nonsense +about the Russian hacking that's all + + align:start position:0% +about the Russian hacking that's all + + + align:start position:0% +about the Russian hacking that's all +garbage but this stuff is real and it's + + align:start position:0% +garbage but this stuff is real and it's + + + align:start position:0% +garbage but this stuff is real and it's +that's right in front of our eyes it's + + align:start position:0% +that's right in front of our eyes it's + + + align:start position:0% +that's right in front of our eyes it's +the people we know you know MIT students + + align:start position:0% +the people we know you know MIT students + + + align:start position:0% +the people we know you know MIT students +going off to work in these things and it + + align:start position:0% +going off to work in these things and it + + + align:start position:0% +going off to work in these things and it +has a big effect on controlling formal + + align:start position:0% +has a big effect on controlling formal + + + align:start position:0% +has a big effect on controlling formal +democratic systems they feel this is + + align:start position:0% +democratic systems they feel this is + + + align:start position:0% +democratic systems they feel this is +Steve Bannon this is his image of how + + align:start position:0% +Steve Bannon this is his image of how + + + align:start position:0% +Steve Bannon this is his image of how +you control the world you know these are + + align:start position:0% +you control the world you know these are + + + align:start position:0% +you control the world you know these are +people who are influential they have + + align:start position:0% +people who are influential they have + + + align:start position:0% +people who are influential they have +tons of money they deeply reactionary + + align:start position:0% +tons of money they deeply reactionary + + + align:start position:0% +tons of money they deeply reactionary +and they have a fee they want to use + + align:start position:0% +and they have a fee they want to use + + + align:start position:0% +and they have a fee they want to use +modern data processing + + align:start position:0% +modern data processing + + + align:start position:0% +modern data processing +you know big data statistical analysis + + align:start position:0% +you know big data statistical analysis + + + align:start position:0% +you know big data statistical analysis +and so on to see if you can just find + + align:start position:0% +and so on to see if you can just find + + + align:start position:0% +and so on to see if you can just find +ways of swinging elections by going + + align:start position:0% +ways of swinging elections by going + + + align:start position:0% +ways of swinging elections by going +after individual vulnerabilities using + + align:start position:0% +after individual vulnerabilities using + + + align:start position:0% +after individual vulnerabilities using +the massive data that people provide + + align:start position:0% +the massive data that people provide + + + align:start position:0% +the massive data that people provide +through Google and Facebook and all of + + align:start position:0% +through Google and Facebook and all of + + + align:start position:0% +through Google and Facebook and all of +this stuff I mean Google and the rest of + + align:start position:0% +this stuff I mean Google and the rest of + + + align:start position:0% +this stuff I mean Google and the rest of +music for advertisers so that + + align:start position:0% +music for advertisers so that + + + align:start position:0% +music for advertisers so that +advertisers can go after you + + align:start position:0% +advertisers can go after you + + + align:start position:0% +advertisers can go after you +individually and say you know like you + + align:start position:0% +individually and say you know like you + + + align:start position:0% +individually and say you know like you +know you try to get a book on Amazon and + + align:start position:0% +know you try to get a book on Amazon and + + + align:start position:0% +know you try to get a book on Amazon and +they suggest ten other books you ought + + align:start position:0% +they suggest ten other books you ought + + + align:start position:0% +they suggest ten other books you ought +to buy because they've got so much + + align:start position:0% +to buy because they've got so much + + + align:start position:0% +to buy because they've got so much +information on you that they think may + + align:start position:0% +information on you that they think may + + + align:start position:0% +information on you that they think may +be way back and sort of getting to sell + + align:start position:0% +be way back and sort of getting to sell + + + align:start position:0% +be way back and sort of getting to sell +this one that's going on all the time + + align:start position:0% +this one that's going on all the time + + + align:start position:0% +this one that's going on all the time +but here it's right in the middle of the + + align:start position:0% +but here it's right in the middle of the + + + align:start position:0% +but here it's right in the middle of the +political system and it's really + + align:start position:0% +political system and it's really + + + align:start position:0% +political system and it's really +significant quite unlike the Russian + + align:start position:0% +significant quite unlike the Russian + + + align:start position:0% +significant quite unlike the Russian +hacking story this is real and it's not + + align:start position:0% +hacking story this is real and it's not + + + align:start position:0% +hacking story this is real and it's not +very far from us facts happening right + + align:start position:0% +very far from us facts happening right + + + align:start position:0% +very far from us facts happening right +here you know there are things that can + + align:start position:0% +here you know there are things that can + + + align:start position:0% +here you know there are things that can +be done about that + + align:start position:0% +be done about that + + + align:start position:0% +be done about that +like exposing it for one thing these + + align:start position:0% +like exposing it for one thing these + + + align:start position:0% +like exposing it for one thing these +should be live issues I think among + + align:start position:0% +should be live issues I think among + + + align:start position:0% +should be live issues I think among +students do we want to devote our lives + + align:start position:0% +students do we want to devote our lives + + + align:start position:0% +students do we want to devote our lives +to destroying democracy maybe \ No newline at end of file diff --git a/oPb9AWMN2fY.txt b/oPb9AWMN2fY.txt new file mode 100644 index 0000000000000000000000000000000000000000..7ceee78ec35860ed08a92556a6ee026ebb73ac13 --- /dev/null +++ b/oPb9AWMN2fY.txt @@ -0,0 +1,3853 @@ +The following +content is provided + +under a Creative +Commons license. + +Your support will help MIT +OpenCourseWare continue + +to offer high quality +educational resources for free. + +To make a donation or to +view additional materials + +from hundreds of MIT courses, +visit MIT OpenCourseWare + +at ocw.mit.edu. + +PROFESSOR: All right. + +Good afternoon, everyone, again. + +Today, our session is going +to be on motion perception + +and pursuit eye movements. + +Now, I want to remind you that +to our next class next Monday + +is going to be a +whirlwind review. + +And then the next +Wednesday we are + +going to have the +midterm exam on what + +we have covered so +far in the course. + +And as I've mentioned already +to you a couple of times, + +that is going to consist of +a series of multiple choice + +questions in which +you have to circle + +the appropriate choice +for each question. + +Then the following week, which +is going to be November 28, + +is when Chris-- + +AUDIENCE: October. + +PROFESSOR: Huh? + +AUDIENCE: October 28. + +PROFESSOR: Sorry, October what? + +AUDIENCE: 28th. + +PROFESSOR: October 28. + +Yeah, October 28-- +that's when Chris Brown + +is going to start the second +half of the course on audition. + +So that is the general +plan at this point. + +And again, I'm going to send +around an attendance sheet. + +So just put your name on it and +send it around, please, for me. + +Thank you. + +All right, so I +think you're going + +to find talking about motion +perception a lot of fun. + +I have several demonstrations. + +And it is certainly have +a very interesting topic. + +And I'm going to highlight that +by first of all telling you + +what we are going to cover. + +And then we are going to talk +about the basic mechanisms + +of direction selectivity +in the visual cortex. + +So first of all, +as I've said, we're + +going to talk about the neurons +in the brain that code motion. + +I'm going to talk about it +mostly for in the cortex. + +But I would also say a few words +about direction selective cells + +that you find in the retina +that we had mentioned before. + +All right, so we are going +to then discuss briefly + +the possible +mechanisms that make + +it feasible to process motion. + +And then we are +going to look at what + +happens when you make various +brain lesions in determining + +how well you can process depth. + +Then we're going to talk about +a very interesting topic, which + +is structure for motion. + +And then further +pursuing that, we're + +going to talk about +apparent motion. + +And then we are going to talk +about an interesting temporal + +effect which is +called metacontrast. + +And then we are going to talk +about optokynetic nystagmus, + +where we link the visual input +to the generation of pursuit + +eye movements. + +Then that is accomplished by +the so-called accessory optic + +system that I will +describe to you. + +And that is also the topic +that, if you remember, + +you will be writing a paper on. + +Lastly then, we are +going to have a summary. + +OK, so let's look first +at the neural responses + +to motion in the cortex. + +Now, one of the most +remarkable features + +of the visual cortex and +extra cortical areas, + +as I had already mentioned, +is that the majority + +of cells in these areas +are direction selective, + +meaning that they respond to one +particular direction of motion, + +but not to the +opposite direction. + +Now, this is extremely evident +in the visual cortex, where + +the so-called simple cells, +virtually all of them + +are direction selective. + +So that's one of the +major transforms, + +if you remember, of +the input that you + +have from the lateral +geniculate nucleus that + +goes to the cortex. + +That input is just from single +cells, on and off single cells, + +midget and parasol cells that +have circular receptive fields + +that centers around antagonism. + +And when they get +up to the cortex, + +a transformation +takes place by virtue + +of intracortical circuits +that turns these cells + +into direction specific +ones and cells that + +are orientation specific. + +So let's look at this first +by starting with a method + +so that you'll understand +exactly how this is done. + +In this case, what +we are going to do + +is we are going to +have a photo cell. + +Let's just look at +the top one here, + +A. You're going to have a +photo cell that responds both + +to a light edge and a dark edge. + +And so when this bar moves +across this photo cell, + +it will activate it. + +And what they're +going to do-- we + +are going to move it +across in one direction. + +And then we are going +to move it back across + +in the other direction. + +And this is shown here. + +This is a time scale. + +And it shows that when +this edge goes across, + +it activates the photo +cell, gives it the beep. + +And then when the +trailing edge goes across, + +it also does the same thing. + +So this is the +light edge response. + +This is the dark edge response. + +Now, when you're going +back the other way, + +you're going to have, +again, the same arrangement. + +In the opposite direction, +the light edge responds first. + +And the dark edge +responds second. + +Now we are going to make +a change so that it mimics + +the organization of simple +cells in the visual cortex. + +We're going to put +two photo cells, one + +which responds to the light +edge and a dark one which + +responds to the dark edge. + +So now when this bar goes across +and activates these two photo + +cells, what happens is, because +they are not all centered + +exactly in the middle, +it takes a longer time + +to activate the two successive +[INAUDIBLE] when the bar goes + +across this way and +a short time when + +it goes across the other way. + +Now, the opposite happens +when you have a dark bar, + +because then the dark +bar doesn't activate + +the light sensitive photo cell. + +It activities the dark one. + +So it takes a little +longer to start that. + +So that then shows you +the temporal arrangements + +of these responses if +when the photo cells + +are arranged in this fashion. + +Everybody understand that? + +OK, so now we are going +to do this for the real. + +We are going to look +at a cortical cell. + +And there are several different +subclasses of simple cells. + +And the first +subclass we can refer + +to as an S1, S for simple, OK? + +So the simple cell +there is an example, + +very similar arrangement. + +Here's the receptive field +of the cell, undefined. + +And you either put a light +edge across back and forth + +or a dark edge back and forth. + +This is the light edge response. + +This is the dark edge response. + +Now, you can readily +see what happens + +here, which is quite remarkable. + +The cell responds only +when the bar moves upward + +across the receptive +field and does not + +respond when it moves downward. + +So this cell is over +100% direction selective. + +Got it? + +All right. + +Now, the same thing happens +to the dark edge, all right? + +And so this cell is one that +responds only to the dark edge, + +OK? + +In this case, it's +the trailing edge. + +In this case, it's +the leading edge. + +Now, at the bottom +here, you draw out + +what the receptive +field looks like. + +This is in 10th of degrees. + +And so this is pretty much +just the spatial response + +of the cell. + +And it only responds +in this direction. + +There's nothing drawn +in the other way. + +Now I'm going to show +you another cell, which + +is going to be a +so-called S2 cell. + +Now, this cell is different +in that it responds + +both to the light +and the dark edges. + +And the fact that they're-- +in this case, a light bar, + +in this case, a dark bar, the +fact that they're-- displaced + +temporally mean that they're +side by side for the light + +and dark responses +rather than overlapping. + +And that, of course, is the +definition of a simple cell. + +And so if you draw out the +receptive field of this cell, + +once again, the cell is almost +100% direction selective. + +And this is what its +response looks like in space. + +Now we are going to +look at yet another one. + +And this is going +to be a surprise. + +It was certainly a surprise +when this was discovered, + +because it's still +not understood + +why we have these +kinds of cells. + +Here is one-- you +can look at that-- + +that responds to a light edge in +this direction and a dark edge + +in this direction, OK? + +So both subfields are +direction selective. + +But they're direction selective +in opposite directions, + +as depicted here. + +Now why on earth would you have +cells in the visual cortex that + +respond selectively to +light and dark edges + +in opposite directions? + +That's something +you can contemplate. + +There is no definitive +answer to that, + +and so I'm not going to +belabor it any further? + +Now what I can do is I can +provide you with a summary. + +I showed you this one, +this one, and this one. + +Now, you don't have +to worry about those. + +But I would like you to +look at this last one, which + +is a complex cell. + +In a complex cell, the light +and dark edge responses + +are in the same location, +space-wise, as shown here. + +And this particular complex +cell that's a real cell + +is 100% direction selective. + +Now, it's true not +for all complex cells, + +but the majority of +them that they too + +are direction selective. + +So I can safely +tell you that one + +of the major transforms that +happens in the brain in vision + +is to convert the signals +form the retina into direction + +selective cells. + +And therefore, we +can only surmise + +that to have direction +selective cells is extremely + +important for us to +be able to process + +motion information in the world. + +So now we are going +to move on and look + +at extrastriate cortex. + +And we already talked +briefly about MT and MST. + +In these two areas, we have +even an stronger disposition + +for cells to be +direction selective. + +And here's an example +of a cell in MT-- + +in this direction of +motion, a vigorous response. + +This is a cumulative response. + +In the opposite direction, it +actually has some inhibition, + +as you can see here and here. + +Then if you recall from MST, +which is an area yet further + +removed from area V1-- it's the +middle superior temporal area-- + +what you find is, again, +very strongly direction + +selective cells. + +Most of them-- maybe +not all of them, + +but the overwhelming majority of +them-- are direction selective. + +But they have much, much +larger receptive fields + +than cells do in MT. + +And as I've mentioned to you +before, one of the basic rules + +is that as you +progress from the V1 + +to higher cortical +areas, the receptive + +fields in these progressively +higher areas become + +bigger and bigger and cover more +and more of the visual space. + +So here you can +see this is shown + +in terms of the +visual field here. + +This is way out. + +This is 20 degrees +just from here to here. + +The receptive is +gigantic, actually. + +And there's a beautiful, +very lawful arrangement + +and even though many, many cells +feed into this particular cell + +from earlier portions +of the visual cortex, + +they maintain or get a specific +input from all of the cells + +that have this +direction selectivity. + +Now, whether this direction +selectivity is a product + +of the input from the cells, +which have the same kind + +of directions, like many, +many of these cells-- + +maybe 20 or 30 or 40 +or 50 of them, OK?-- + +which have the same +orientation and direction, + +or whether orientation and +direction selectivity are + +created anew in MST is +something that can be debated. + +It is still not 100% certain. + +So the only thing we have +to worry about this time is + +to realize-- maybe +not even worry. + +That's too strong a +term-- is to be aware + +that there is +prevalence of direction + +selectivity in both MT and MST. + +It's very beautiful and +very, very specific, + +as you can see it +here, even when + +you have a huge receptive field. + +So that is the basic story then. + +And now we can ask the +question, how on earth + +is direction +selectivity created? + +Now, there are several models +that have been proposed. + +And most of these models-- I'll +show you a simple one just so + +that you have a sense for it-- +most of these models assume, + +I believe correctly, +that you need + +to have inhibitory circuits +that are selective for direction + +to produce this specific +response in these cells. + +Now, the amazing +thing about all this + +is that already +in the retina you + +have some cells that +are direction selective. + +And these cells I'll +talk about a bit more + +when we talk about the +accessory optic system. + +These cells in the retina +are not very numerous. + +In the rabbit that has +approximately 350,000 cells + +in each retina-- can you +imagine a little rabbit? + +And it has 350,000 cells. + +We have a little +over a million, OK? + +And among those 350,000 +cells, about 7,000 + +are the so-called +cells of Dogiel. + +And actually, I'll +come back to that. + +And those are direction +selective cells. + +So a very clever experimentalist +examined these direction + +selective cells in the retina, +a fellow called Nigel Daw. + +And he asked the +question, what can I + +do to determine what +the mechanism is + +of direction selectivity? + +So he did an experiment +that sounds simple. + +But let me tell you, it's a +very difficult experiment. + +When you put your +electrode into the retina, + +you can't see direction +selective cells. + +So you're on a +hunting expedition. + +So you keep recording from +cell after cell after cell. + +And if indeed only +7,000 among the 350,000 + +are direction selective, it +will take you quite a while + +before you manage to record +from a direction selective cell. + +So it's a lot of very hard work. + +So anyway, if you do that +when your hypothesis is + +that some sort of inhibitory +mechanism is involved, then + +you can do an +experiment and say, + +well if it's inhibitory +mechanisms, probably + +some sort of +GABAergic system, we + +need to put some agent into the +retina that blocks inhibition. + +We talked about that before, +that that can happen. + +And so in this case, +what they did-- let + +me come to that first. + +Let me see. + +Here we are. + +I'll come back to the +others in just a minute. + +What we have here is +one of these cells. + +And we move in +this direction here + +and in this direction for this. + +And you can see that this cell +is very strongly direction + +selective, maybe 100%, +but maybe 80% or 90%. + +Then he injected picrotoxin +into the eye that blocks GABA. + +And lo and behold, +direction selectivity + +is virtually eliminated. + +And then when picrotoxin +got washed out, + +there was recovery, all right? + +So now, on the basis +of this finding-- + +it's a beautiful finding-- it +was established that indeed, + +inhibitory circuits play a +central role in giving rise + +to direction selectivity. + +And you can imagine that +in the course of evolution, + +the pressures had to +be tremendous to create + +these direction selective +cells, because the circuitry is + +very complicated. + +You have to create these +inhibitory neurons which + +inhibit in a particular +direction rather than just + +randomly. + +So that's what was done. + +And so I'll show you one +model that describes this. + +You have a bunch of-- +this is for the retina. + +You have a bunch +of receptors here. + +And they activate a +retinal ganglion cell here. + +But they also connect with +an inhibitory interneuron + +in one direction, +in that direction. + +So now if you move a bar in +this direction, as shown here, + +you get no response. + +But if you move a bar +across the other way, + +you get a vigorous response, +as shown by the action + +potentials here. + +So this is a fairly simple +model of creating direction + +selectivity by virtue of +inhibitory interneurons. + +So that then was also +examined in the cortex. + +it was found that there +too inhibitory interneurons + +play a central role when +direction specificity is + +created in a cortical cell. + +So that now makes me come +back to a further analysis + +of the basic nature of motion. + +Can we logically divide motion +into several types, or what? + +And so it was proposed by a +wonderful scientist called + +Wurtz at the National Institutes +of Health that he could-- + +he decided that +you can distinguish + +between planar motion, circular +motion, and radial motion. + +Planar motion is when +something moves straight. + +That's what we've talked +about so far only. + +And of course, you can do that. + +In this case, he shows +four different directions. + +But of course, +there'd be all kinds + +of directions that are +not vertical or horizontal + +but are diagonal. + +And there are many, +many cortical cells. + +Some of those actually I +showed you had orientation cell + +activity that was at an angle. + +So you have a huge number +of different angles. + +And these cells +hypothetically then + +would respond to planar motion. + +Then you have another +type of motion, + +which is called circular. + +And let me tell you, when you +see circular motion, obviously, + +if you were to be spun around +or something, you'd see it. + +But it's not uncommon +to see something rotate. + +So if you have a spinning wheel +or if you watch a tire rotating + +in motion, that's +circular motion. + +And so the hypothesis +is that there + +should be cells in the brain +that selectively respond + +to circular motion, either +clockwise or counterclockwise. + +And lastly, of course, the +so-called radial motion-- + +and you encounter that +just about every day. + +Whenever you drive, +you see trees. + +Or if you're driving +out in the country, + +you see trees going past you, so +to speak, as you drive forward. + +And that would be motion +which would be outward. + +Or if you were to +back up like this, + +then you would get +this kind of motion + +where things would +come together, OK? + +So that kind of motion +is certainly one + +that you need to somehow code. + +And so another question +came up once he came up + +with this hypothesis that these +different kinds of motion-- + +the question is, are there cells +in various parts of the brain, + +especially in higher +areas like MST, + +that are selective for these +three basic types of motion? + +And so they began +to do an experiment. + +And I'll show you some +summary data here. + +Here is a cell when you +study planar motion. + +And these are the eight +directions of motion + +that were studied-- +sorry, four directions + +of motion on the top-- then the +circular one on the next two, + +and the in and out +motion at the bottom. + +This particular cell seems to +be specific for planar motion + +from right to left. + +Now here is a cell that is +selective to circular motion, + +OK? + +And lastly, here +is a cell that's + +elective to radial motion. + +So if you only had +recorded in your life + +from three cells in +MST, and it happened + +to be these three +cells, you would say, + +ah, my hypothesis is right. + +There are three +kinds of cells in MST + +that respond selectively to +these three classes of motion. + +So everything is incredibly +beautiful and logical. + +But of course, that's not how +you do your experiment, is it? + +The way you do +your experiment is + +you record from +MST in this case, + +and you record from +many, many, many cells. + +And you test them +just like this, OK? + +And if you do that, you +realize that this is just + +an example of three +cells that were specific. + +It was found that +40% of the cells + +responded to all +three kinds of motion. + +305 responded to +two types of motion. + +And only 20% of +the cells responded + +to one type of motion. + +So therefore, these +cells, as is so often + +the case in the visual cortex, +are not unique and specific + +to analysis of one thing. + +These cells can tell you +about all three of those. + +And what happens in reality then +is that when something moves, + +you activate thousands +of cells in MT, MST, + +and visual cortex, +maybe tens of thousands. + +And it's some sort of +complex relative activity + +that then eventually gives +rise to the fact that you say, + +oh, yeah I see planar motion. + +Oh, yeah, I see a +circular motion, + +or I see in and outward motion. + +So it's not a +specific single cell + +that tells you or gives +you that impression, + +but it's the concerted +activity of thousands + +of cells even for the +simplest of cases. + +So that's the way it works. + +It's a complex business. + +And the idea that was +popular at one time, + +namely that you have feature +detectors in the brain, + +has become downgraded +progressively + +with increasing research. + +As I mentioned to +you before, when + +we talked about to +extrastriate cortex, + +the initial idea was when the +various extrastriate areas + +had been discovered, that +each area specializes + +in one particular thing. + +And then it turned out +that that is not the case. + +There may be shifts or +trends, but in each area, + +many different +things are analyzed + +and thousands and +thousands of cells + +are active whose relative +activity is somehow + +what gives rise to the +percept that you have. + +All right, so that +then is the essence + +of the layout of the +responses and the models + +that this model that +[INAUDIBLE] told you about, + +or something similar to this. + +It may be a bit +more complicated. + +And some people +have hypothesized + +that there are temporal +delays necessary to produce + +this thing. + +Yes? + +AUDIENCE: Sorry. + +There was a 10% missing +in the breakdown. + +PROFESSOR: Sorry. + +Are you talking about this? + +AUDIENCE: Yeah. + +PROFESSOR: Well, that's-- 10% +of the cells were unclassified + +or we're not +direction selective. + +These they could with certainty +say what the situation was. + +And maybe some of +those cells they + +lost while that +we're recording from + +or they didn't have any +particular direction + +selectivity. + +And because of that, +they couldn't come up + +with 100%, of course, yeah? + +Yes, you had a question. + +AUDIENCE: It was +the same question. + +PROFESSOR: What? + +AUDIENCE: It was +the same question. + +PROFESSOR: Same question, OK. + +Very observant-- good for you. + +All right, so now we are +going to move forward + +and we're going to look +at the effects of lesions + +on motion perception. + +One of the ready ways you +can assess to what extent + +various higher +cortical areas play + +a role in various +neural mechanisms + +is to either reversibly +inactivate them + +or to remove them by making +lesions and then determining + +what happens. + +And if you remember, I +talked about this a bit. + +I told you, for example, +that the hypothesis that + +was made initially about area +V4 is that it's a color area. + +That was a single +function hypothesis. + +And then it turned out that +when area V4 was removed, + +it was found that there was +only a moderate to mild deficit + +in color vision. + +But there were all +kinds of other deficits + +that we had discussed +in previous sessions. + +So now we come to +the question about, + +what about motion perception? + +When we talk about emotion +perception, we of course + +are dealing with +temporal things, + +because motion involves +successive activation of cells. + +And because of that, +it's also very important + +to study how well we can process +rapid successive presentations + +as, for example, in flicker. + +And that brings me, of +course, to the story-- + +and we will talk about +that in a minute-- + +that in the olden days, when +movies were first invented, + +the rate at which successive +frames were presented + +was 16 Hertz, which was +fairly close to having + +a sensational of +flicker, all right? + +And because of +that, what happened + +when a guy asked a +girl to go the movies? + +How did the guy ask the +person to go to the movies? + +Can anybody remember that? + +That's an olden thing. + +The guy would say, +hey, how would you + +like to go to the +flicks tonight? + +OK, you've heard that +expression, go to the flicks, + +right? + +Well, nowadays we are not +aware of flicks anymore. + +And there are two +reasons for that. + +Anybody know what +the two reasons are + +why no one can see +clicks in the movies + +and you no longer go +to the flicks anymore + +but you go to the +movies instead? + +Yeah? + +What are the two reasons? + +Anybody know? + +OK, well, let me tell you. + +The first is that the rate of +the number of frames per second + +had been increased +to about 24, OK? + +But that's still slightly +below the effusion. + +OK? + +You can still see some flicker. + +So how do you get rid of it? + +Well, let me tell you, some +incredibly clever guy-- + +some things are +really, really clever. + +I'll tell you what this +person came up with. + +He said, all right, +what we'll do + +is we're going to create +a shutter which is round. + +And it's going to +have one opening here. + +And then we're going to +have a second opening here. + +And then we're going to +have a third opening here. + +So this goes around. + +And each frame you're +going to show three times. + +And then as this goes around, +you go to the next frame, + +and you show it three times. + +So actually, if seeing frames +24 hertz, you see it 3 times 24, + +OK? + +But each frame is +shown three times. + +Now, to be even more clever, +the way they did this, + +they took two of these +circular shutters. + +And one of them moved in +this direction and the other + +in that direction. + +They sort of equalized +from the center + +out as the light was +expose from the projector. + +So that then reduced +the rate of flicker. + +So therefore, we can +next ask the question, + +what is the flicker rate +at which you no longer can + +see anything? + +I mean, do you want +to see flicker. + +Or do you not want to +see flicker, and so on? + +And so experiments +were done, hundreds + +of experiments in which +a psychologist studied + +flicker rate, varying +contrast, varying color, doing + +this, doing that, and then +varying the spatial frequency + +and generating curves to +see what they look like. + +So that's the process. + +And so what we can do +next is to examine this. + +And one way to do +this, for example, + +just to give you +a sense, you can + +have, for example, a +bunch of random dots, + +just like we had for the +[INAUDIBLE] stereogram. + +And this would be done +with a monkey, for example. + +The monkey fixates. + +And then you start something +in motion-- ready?-- like that. + +And the monkey sees this and +has to make a saccade to it. + +And when he does so, he gets a +drop of apple juice for reward. + +And then what you can +very are two things. + +You can vary the frequency. + +I'm showing another one, +much higher frequency. + +Bang-- the monkey goes +there and gets rewarded. + +Or you can-- and/or, +actually-- you + +can vary the contrast +of the display, OK? + +So once you have a sense of when +you get fairly close to sort + +of the edge of things, then +you can also vary the contrast. + +So now let's ask +the question, what + +happens when you remove area +MT and when you remove V4, OK? + +So think about +that for a second. + +And then I will show you +the actual data, all right? + +OK, here we go. + +Here is an example. + +This is motion detection. + +And here we vary percent +luminance contrast + +at a fixed frequency. + +You get the same +effect the other way. + +I'll just show you this one. + +And you can see very readily +that the V4 lesion caused + +no deficit at all, but the MT +lesion produced a huge deficit, + +OK? + +So clearly this +establishes the fact + +that area MT plays +a central role + +in the processing of +flicker information + +in being able to analyze +rapid temporal events. + +And now we can ask +the next question. + +What happens when you actually +do just stationary flicker, + +all right? + +So when you do +stationary flicker, + +you can do that in two ways. + +You can do an on +off flicker, or you + +can do a flicker between two +colors, for example, all right? + +And you can see why that +would be interesting. + +Because if you do flicker +between two colors, + +like red and green, +if area V4 were + +important for color processing, +then a lesion in that area + +should mess up that +kind of flicker. + +So that's the way to do it. + +So let me show you first of +all how you do this experiment. + +Here we have it. + +You have a bunch of LED's. + +Why does one have LED's +instead of just doing + +this on a monitor? + +Any thoughts? + +Yes. + +AUDIENCE: The frequency at +which those [INAUDIBLE]. + +PROFESSOR: Very good. + +The reason you do it is because +your typical frequency rate + +is the alternating current +rate, meaning 60 Hertz. + +Now, nowadays you +can of course buy + +devices that can double +it or even quadruple it. + +But back then it was +easier to do it this way. + +And it still is, because +you can vary these flicker + +rates in small amounts. + +Now, each of these +LED's, actually, + +for this particular +set of experiments, + +is one that has both +red and green in it, OK? + +So you can flicker between on +and off, let's say for green. + +Or you can flicker between +red and green, all right? + +So that's what we are +going to find out. + +What happens when you do these +kinds of flickers, red green + +as well as on and off? + +And ask the question, +what happens + +when you make, again a V4 +lesion or an MT lesion, OK? + +Now think about it +for a minute, as + +to what you would +expect in terms + +of the differences between on +and off and red green flicker + +and possible differences +in the lesions + +that cause a +deficit in this, OK? + +All right, ready? + +Here we go. + +There is the flicker. + +You can see that. + +Now, the way that really works +is that the overall flicker-- + +I'll show it to you again-- +is done in such a fashion that + +the mean illumination level +is the same so that you cannot + +tell the location of the +flickering LED on the basis + +of a lumen exchange. + +You can only tell on the basis +of the fact that it flickers + +or it doesn't flicker, OK? + +All right, so we are now +ready for the experiment. + +And here it is. + +On the right, I'm showing you +a green on and off flicker. + +And you can see that there's +no deficit at the V4 lesion, + +but a gigantic, absolutely +gigantic deficit at the MT + +lesion site. + +And then very surprisingly-- to +some people at least who were + +convinced that V4 +is a color area-- + +when you do that for a red +green flicker, first of all, + +notice that the flicker rate +that you can detect is much + +lower-- OK, this is the ratio of +the flicker, much lower, OK?-- + +than it is for the +on off flicker. + +And secondly, again, there's +no significant deficit + +with the V4 lesion. + +But there's again a major +deficit with MT lesion. + +So area MT is +essential for being + +able to process both red and +green flicker as well as on + +and off flicker, all right? + +So bear that in mind as we +are going to now progress + +to the next stage of the +experiment-- set of experiments + +I should say. + +And the next step I'm +going to talk about + +is structure from motion. + +And that one is a very important +attribute that we have. + +We can reconstruct structure +by see nothing but motion. + +And I'm going to show +you an example of that. + +OK, let me tell you, +this here actually + +is a scene, a made-up +scene, that's outside. + +And somewhere in here +we have ladybug hiding. + +But the ladybug +is not in motion. + +And you know, ladybugs have +these spots on their back. + +And there's a ladybug here. + +And I'm going to tell you that +there's a monkey watching this, + +hoping that he could catch +the ladybug to have it, + +because he loves +to eat ladybugs. + +Are you ready to catch her? + +OK, here we go. + +Ready? + +The ladybug after a while got +tired of just sitting there + +and began to move. + +And that's a dead +giveaway, because you + +have all these +cells in your brain + +that selectivity see +motion and flicker. + +Are you ready? + +Here we go. + +There's the ladybug. + +See her? + +OK, so the monkey is happily +eating away the ladybug, + +all right? + +So here is a good example +of how incredibly useful + +motion information +is that you have + +in these visual cortical areas. + +Now, I would bet that if this +monkey had had his MT removed, + +he wouldn't have been able +to catch that ladybug. + +Now, another set of +experiments carried out, + +beautiful experiments, +were carried out + +by a fellow called +Johanson-- I think + +that was in Sweden-- who did a +very clever set of experiments. + +He wanted to analyze how well we +can process motion information + +and derive structure from it. + +And what he did was that he +put little teeny little light + +bulbs on about 13 points +in the human's body. + +He put some here on the +elbows, put some at the hand, + +put some at the head, and +so on down, 13 of them. + +And then he turned +off all the lights, + +so the only light was that +little spot of light that + +was on these 13 spots of +light that were on the person. + +And then he took a +movie to see what + +happened when this +person started to walk. + +And he discovered +something amazing, + +that we are incredibly capable +of reconstructing shape + +from minimal motion information. + +So are you ready? + +OK, here we go. + +So there it is. + +There are your 13 +little spots of light. + +And now I'm going +to set it in motion. + +Ready? + +So what do you see? + +You see a person walking on +this very minimal information. + +And you can even tell-- +who would say it's a male + +and who would say it's a female? + +Those of you who say it's +a male, raise your hands. + +OK, it's virtually everybody. + +Right, very good. + +Now, so what he did which +I don't have a movie of, + +which is quite +remarkable, is that he + +took a couple, a +male and a female + +and had them arranged in +exactly the same way-- each + +had 13 of those bulbs-- +and had them dance. + +And when you looked at +that, you had no trouble + +telling which was the male +and which was the female. + +Amazing. + +So we are able to reconstruct +a tremendous amount of form + +detail on the basis of +extremely limited information + +about motion. + +All right, so that +then ends that session. + +And we're going to go next to +what is called apparent motion, + +all right? + +So you're going to have various +forms of apparent motion + +I'm going to tell you about. + +And the first one is that if you +show these two dots, if I flick + +them back and forth, you +have a very strong sense + +that the thing is going +back and forth, right? + +You don't see one, two, +going on and one going off, + +because of the right +temporal succession. + +But you see them as just +jumping back and forth. + +So now what we can do-- +we can enlarge on that + +and carry out a series of +experiments on the bases + +which can make some inferences +as to whether areas V4 + +or MT are contributing to this. + +So this is going be fun for you. + +And I want you to +pay close attention. + +Now, in this kind of +experiment when it was done, + +first, this stayed +on all the time. + +And these two dots +came on first. + +And then these two +dots came on second. + +Now, if you do that, you can see +either of two types of motion. + +You can either see what +we call zigzag or seesaw. + +Seesaw is going to look +like that, obviously, + +and zigzag like this, OK? + +So that's what I'm +going to show you. + +And once I set +this in motion, you + +will see it one +way or the other. + +Then if you see +it's, say, seesawing, + +you can take your finger +and move it horizontally + +back and forth on top, say. + +And then in short order you're +going to be seeing this. + +You can reverse the sense +of motion, all right? + +So are you ready for that? + +OK, so here we go. + +If you see it one +way or the other, + +try to move your finger back and +forth to change it to see it. + +If you see it horizontally +moving, move it vertically. + +If you see it vertically, +move it horizontally. + +And then you can see it shift. + +Everybody able to reverse it? + +Well, keep doing it. + +And you should have no +trouble reversing it + +if you move your +finger back and forth. + +This is a bistable situation. + +And people can readily +see the switch. + +OK, most of you +seeing it switching? + +All right. + +So now we can ask a +whole bunch of questions. + +And the way to put this +question in general + +is we can ask, is first of +all, is this something that + +happens locally, or does +it happen everywhere + +when you're looking? + +So how can you do that? + +So let me show you. + +What they we do here instead is +we can put up a bunch of them, + +OK? + +And they're quite far +apart from each other. + +And depending on +how close you are, + +they may be as far +as a centimeter + +apart in the visual +cortex for the activation. + +So now what we're +going to do is we're + +going to move them back and +forth just like I did before. + +And the question +that you want to ask + +yourself-- am I going +to see these all + +move the same way vertically, +say, or see all of them + +move horizontally, OK? + +So here we go. + +Are you ready? + +Basically, the rule is that +they all move the same way. + +And then they shift. + +Again, you can use your +thumb or your forefinger. + +And if you manage +to make it switch, + +they all will switch +at the same time. + +OK, everybody manage that? + +All right, so now the rule is +that even though the activation + +is very far apart in +V1 from here to here, + +there's some organizing +principle that + +makes you see everything +a particular given way. + +And they shift. + +They all shift. + +Now, that's a very +interesting arrangement. + +And you can wonder, +what is there + +that can tell the visual +cortex how to see it and insist + +that you got to see +it the same way? + +Now we can move on. + +And you can ask the +question-- so far, + +what I've shown you is +they're all the same-- sorry. + +That's my fault. + +They are all the same size. + +And they are geometrically +arranged, OK? + +So now what happens if +instead, we do it differently + +and we make them different +sizes and random locations? + +What happens under +these conditions? + +Now think about it for a minute. + +And then I'm going +to show it to you. + +And once again, even though +they're different sizes, + +different locations, +they all go the same way. + +And when they shift-- +again, use your forefinger + +to try to make it shift. + +And when they shift, they all +shift at the same time, OK? + +All right, so now we +can move on and ask + +some interesting +additional questions. + +We can ask the +question, how important + +is color information for you to +see it go one way or the other? + +All right? + +OK, so to do that, here we have +the top two are colored red + +and the bottom two +are colored green. + +Now we're going to move +these back and forth. + +And the question is, will you +see them move horizontally + +because of the color +information or what? + +So the question +is, again, are you + +going to see zigzag or seesaw? + +OK, are you ready? + +And you can readily see if, +again, you can readily shift it + +again with your forefinger, +that color doesn't seem + +to be an important determinant +of the direction in which + +the apparent motion +will take place. + +Everybody follow that? + +Well, now think about that. + +How can we do this +experiment to be + +more convinced that +color for some reason + +doesn't seem to be important +in how we see apparent motion? + +Well, let me tell +you how you do it. + +Here is an example. + +Here we have again four rows +and four columns, all right? + +And the first, one A and C, +the colors are horizontal. + +And in the second one, B +and D, they are vertical. + +So if color plays +a role, we should + +be able to see these, the +first and the third rows + +go in one direction +and the second + +and the fourth row go +in the other direction. + +So let's examine that. + +Ready? + +And you can see that they're +all going the same direction + +anyway. + +When they switch, they +switch in the same direction, + +meaning that indeed you pay no +attention to the color itself, + +OK? + +Some mechanism is +involved in which + +the apparent motion +you see does not + +play a significant +role in color. + +Now we can do another +experiment and see + +what happens when +instead of colors, we + +use small shapes, +X's and O's which + +are horizontal in the +first and the third row + +and vertical in the +second and the fourth row. + +Will this succeed in breaking +up the unity of apparent motion? + +So here we go. + +Ready? + +And you still see +them all the same way, + +meaning that you +don't pay attention + +to the small +differences in shape. + +OK, so now what I +have shown you so far, + +remember, has something to do +with the midget and the parasol + +systems for the test. + +The midget system can +process fine detail. + +And the midget system +can process color. + +The parasol system does +not process fine detail + +and does not separately +process color. + +So we'll come to +that in a minute. + +Now let's ask the next question. + +What happens if +you vary the size? + +OK, again, the first and +third row, the size difference + +is horizontal. + +And the second and fourth +row, it's vertical. + +OK, so let's see what happens. + +Here it's a bit unclear, OK? + +So as you see, some +of them go one way. + +Some go the other way. + +And some of you may see +it all go the same way, + +depending on how far you are. + +So let's change the ratio +so it's much, much bigger. + +And if you do it now, +what you see is dramatic. + +You see horizontal motion +in the first and third rows + +and vertical motion in the +second and fourth rows. + +Everybody see that? + +OK, so we can enhance +on this maybe a little + +bit by adding these together, +adding size and color + +and shape, quite large +differences in size and shape + +and color. + +Then if you do this, +you will indeed + +have fully succeeded in +breaking up the unity of motion, + +with the first and third +rows going horizontally + +and the second and fourth +rows going vertically. + +Now then there's one +other important factor + +that we need to +consider about this. + +And that has to +do with proximity. + +So in this case, what +we're doing now-- + +in the first and +the third rows, we + +have the horizontal dots +closer to each other. + +he second and fourth rows, we +have the vertical dots closer + +to each other. + +So if you do that, you're +going to ask the question, + +how important is proximity? + +And if you do that, you +don't see much so far. + +But now what I'm +going to do is I'm + +going to make the +difference even greater, OK? + +The first and third are +very close horizontally. + +And the second and fourth +are very close vertically. + +If you do that, +you readily can see + +that indeed the first and +third rows move horizontally + +and the second and fourth +rows move vertically. + +So proximity is a +very important factor. + +And so that then brings me +to an interesting question + +that probably none of you +have given much thought. + +But I will make you +more aware of it. + +The fact is that +when you see movies, + +you very often see a car or +a chariot or something move + +forward, but the wheels +are going backwards. + +And you certainly +do that when you + +watch those endless ads +on television about cars. + +And you see the wheels going +backwards most of the time. + +And the car is going forward. + +And some of you say, +well, why would I + +buy a car whose wheels +are going backwards? + +So at any rate, let's +examine that question. + +And what I'm going +to do first is + +I'm going to show you a movie. + +Ready? + +This a famous movie, Ben-Hur. + +You've probably seen it. + +Look at the wheels +going backwards. + +Can you see that? + +Now, of course since I have +given this a lot of thought, + +it drives me nuts when I see +wheels going backwards when + +the chariot or the +car goes forward. + +All right, so now +the question is, + +why do we see wheels going +backwards in the movies + +or on the ads on television, +whereas when you see it + +in the real, you never +see them going backwards? + +Well, remember that when you +look at a movie or television, + +you always see apparent motion. + +You never see real +motion on television, + +never see real +motion in the movies. + +You're not aware of +it, but you don't. + +You only see apparent +motion because you + +have successive frames +in each of which there + +is a specific, say, if +it's wheels, rotation, OK? + +So let's look at +that analyze this. + +So I'm going to show you a +wheel that is rotating slowly. + +Are you ready? + +it's a very brief. + +OK, you can see that wheel +is going forward, right? + +Now I'm going to show you +the same and arrangement. + +But I'm going to +have it move fast. + +Ready? + +Ready, go. + +That time you saw it +go backwards, right? + +OK, so let's analyze this. + +What happens when +you have slow motion? + +Let's imagine that +the red line is + +designating one of the spokes. + +Then if it moves +slowly, the next frame + +is going to show that displaced +only a little bit from the red, + +and so on. + +And because of that, you're +going to see forward motion. + +But now if what you do instead +is moving fast, what happens + +is that this spoke here +is going to be closer + +to this one in the next frame. + +And because of that-- +of course, that's + +all of them all the +way around-- you + +will see them go backwards, +because of the principle + +of proximity that I showed +you with the apparent motion + +of the four moving dots. + +OK, so that then explains to +you why you see wheels rotating + +backwards in the movies +and on television. + +And it's due to a +fact of the proximity + +of successive +elements, in this case, + +spokes that are rotating as the +picture is taken with a camera. + +All right. + +So now I'm going to come +up and tell you briefly + +about another very +interesting phenomenon that + +is closely related to motion. + +When two successive +stimuli are presented, + +there can be an interaction +between them, all right? + +And in a famous series of +experiments back in the 1930s, + +they did what is called a +metacontrast experiment. + +First, a disc was +presented like this. + +And then it was +followed by a ring. + +And they shared the +same contour, OK? + +This is it, OK? + +So now what you +could do-- you could + +vary the temporal +interval between them. + +So if you present these +two simultaneously, + +since they have +overlapping contours, + +that's all you would see. + +But then if you present +them sequentially-- ready? + +Like that, then the +question is, to what degree + +did you see that first one? + +So let's look at that. + +And I want you to +pay close attention + +to when I present +this to you, OK? + +Are you ready? + +You're going to do it +now so that they're only + +60 milliseconds apart, OK? + +Here we go. + +You barely see the +first one, right? + +You could just +barely make it out. + +But it's not gone. + +Some people thought it +would cause it to be gone. + +But that's not the case. + +So what you do then +is the following. + +If you fixate on +the red cross, I'm + +going to present the stimuli. + +And I want you to tell me +which of the two stimuli + +I present is +preceded by the disc. + +Ready? + +Could you tell? + +Which one, left or right? + +Left, good. + +Again, repeat. + +AUDIENCE: Right. + +PROFESSOR: Oh. + +Ready? + +AUDIENCE: Left. + +Left. + +PROFESSOR: OK, very good. + +So the fact is that when you +present two side by side where + +one of them is +preceded by the disk, + +you can tell which +one came first. + +So somehow this didn't +obliterate your ability + +to see it. + +Now, the other +interesting fact is + +that if now you flicker +back and forth between them, + +at equal rates, you +see both equally. + +So therefore, what happened +is you did not truly + +obliterate the percept. + +You just somehow weren't +too much aware of it + +because of the +temporal offset between + +the successive presentations. + +Now, you can do this +slightly differently. + +Instead of having two stimuli +that do not overlap but have + +adjacent contours, +we can overlap them. + +So here I'm going to show +you something and ask you + +what you see. + +Ready? + +What do you see? + +A big disk? + +OK? + +There it is. + +Now I show it to you. + +As to what I really +showed you, was first + +I presented a dim small disc +followed by a brighter higher + +contrast bigger disc. + +And that obliterated the +perception of the first one. + +And that is truly obliterated. + +And the interesting experiment +you can do in this regard-- + +you can do this interocularly. + +In other words, you can +present one of the stimuli + +to the left eye and the +other to the right eye. + +If you do that, you don't +get a masking effect. + +But if you go back and +do the metacontrast, + +you still get the +same pseudo blockage + +without actually +eliminating it, but sort + +of making you less aware +of the first stimulus. + +OK, so now if one +examines this, the way + +to do the experiment +right is you + +vary the temporal offset +between the two stimuli. + +And when this was +done systematically + +with the brightness masking +that I showed you later, + +secondly, what happens is that +the effect rapidly declines. + +It's the biggest +when the two are just + +right next to each other. + +By contrast, when you +do the metacontrast, + +the biggest effect is when +they're about 62 to 100 + +milliseconds separated, +because that's + +when apparent motion +is most effective. + +And then if you do an experiment +to see where this happens + +for the brightness +masking, here's + +what happens in the retina +recording from a cell. + +This is a dim stimulus, +a smaller response, + +and with a longer latency. + +And the mask alone will +get a much shorter response + +and a much more vigorous one. + +And then when you systematically +vary the temporal interval + +between the two of +them, you can see + +when the interval becomes short. + +The second stimulus +obliterates the first one + +because it's faster and +it has a bigger response. + +So this explains what +happens, because it happens + +in the retina by +virtue of transmission. + +And the rule of the fact that +the rate at which information + +is transmitted from +the four receptors + +to the retinal ganglion +cells is contrast dependent. + +The higher the contrast, +the faster the response. + +All right, so now +does anybody have + +any questions about the +masking or the metacontrast + +that we talked about so far? + +All right, in that +case, we are now + +going to move on and talk +about another important motion + +perception effect which links +one to eye movement generation. + +And that falls into +the category of + +so-called optokinetic nystagmus. + +So how do you study +optokinetic nystagmus + +at the very basic level? + +Well, the way you study it is, +for example, in the olden days, + +you could take a large +lamp shade like that + +and put vertical bars +on int on the inside, + +have a person have +his head inside. + +And then you rotate +the lamp shape + +so that the bars go +across like that. + +Or you can do that +more simply nowadays. + +You just go put a bunch of +vertical bars on a monitor + +and have them drift. + +And the person is +asked to look at it. + +So when the person +does that, what you get + +is the so-called +optokinetic nystagmus. + +It has two phases. + +It has a fast and a slow phase. + +The fast phase is a saccade, a +resetting saccade, if you will. + +So you watch an edge. + +You follow it. + +And then once it gets +to the periphery, + +you make a saccade back +and you watch the next one. + +And you keep doing it. + +And this shows you the +three different rates. + +Now, this is quite an +interesting mechanism. + +And it was determined that +an important contribution + +to executing these kinds +of eye movements, which + +is very important, because +when you track anything, if you + +track a bird of something, +you keep your eye on it. + +And then once it gets past +you, make this a saccade back + +and take the next +bird and track it. + +So that's the mechanism. + +And it's been shown that +several neural mechanisms play + +a role in it. + +And one of those belongs to +the so-called accessory optic + +system, which has +those cells of Dogiel + +in the retina that +connect to it. + +So we're going to look at that. + +Some beautiful work has +been done about that. + +But before I do +that, let me show you + +a very interesting factor. + +Here is a typical +optokinetic nystagmus + +induced by a drifting vertical +set of bars at various rates, + +as you can see here. + +And this is a rabbit. + +And in the rabbit, what you have +is a left eye and a right eye. + +And you can activate them +separately, as shown here. + +Now, a remarkable +discovery that was made + +is that the accessory +optic system-- that there's + +a primary role in +generating this optokinetic + +nystagmus that is +found initially + +in among the cells of Dogiel, +of which in the rabbit, as I've + +said, there are about 7,000 +out of 350,000 in the eye. + +And it was found-- which +was incredibly surprising-- + +that this system originating +with the cells of Dogiel, + +the cells of Dogiel themselves +get input only from ON bipolar + +cells, OK? + +So what can we do to prove +that this system here indeed + +is one that is activated +by the cells of Dogiel, + +since the cells of +Dogiel in the rabbit + +get input only from +the ON bipolar cells? + +Anybody can think +of an experiment? + +What did I tell you about +the on and off systems + +and how they can be manipulated? + +Anybody remember? + +Now, see you've got +to remember facts. + +And one of the facts was I told +you about what happens when you + +use 2-amino-4-phosphonobutyric +acid, APB. + +Anybody remember that? + +If not, you'd better +study it, because there + +are going to be questions on +that on the exam, of course. + +OK, so if you put +APB into the eye, + +you block the ON bipolar cells. + +And therefore, if +only ON bipolar cells + +feed into the cells +of Dogiel, you + +would expect that if you +block those bipolar cells, + +you should eliminate the +optokinetic nystagmus + +in the eye that had been +injected, if it's indeed true + +that the cells of +Dogiel are involved, OK? + +So that's a +beautiful experiment, + +because it's a definite one +if indeed the data come out + +the way one had hoped. + +And guess what happens? + +Here are the data. + +The red ones are +from the eye that + +had been injected with APB. + +You know, you +blocked the ON cells. + +And hence, you +blocked the responses + +of the cells of +Dogiel, all right? + +So this is a rather nice, +luckily definitive, experiment. + +Now, the curious thing is, if +you did the same experiment + +in a monkey, you +would get nothing. + +Here you do the same +experiment in a monkey. + +Here is your OKN. + +And here is when you put in APB. + +And still after putting +in APB, the monkey + +still does +optokinetic nystagmus. + +That's because the rabbit +is a very unusual species. + +And god only knows +why it happened + +that only On bipolar cells +fed into the cells of Dogiel. + +In the monkey, you get +both ON and OFF cells + +feeding into the +cells of Dogiel. + +All right, so now another +interesting factor + +that I want to +mention just briefly + +is that it's indeed is true +that the feedback mechanism is + +essential for you to do +optokinetic nystagmus right. + +Here is a monkey in which +one eye has been immobilized + +and the other eye is normal. + +So if you look at the +normal eye and you + +move a set of vertical +bars very slowly, + +this is what your +optokinetic nystagmus + +looks like-- just a +very slow tracking. + +But then if you do the same +thing in the mobilized eye, + +and you, of course, record the +eye movement of the other eye + +which is blocked, what you +get is a tremendously rapid + +increase in the +pursuit movement. + +This can be called open loop. + +And this can be +called closed loop. + +Now, the mechanism +involved here is + +that your intent is to track. + +But when you realize-- +or not you realize, + +but the brain realizes. + +You're not even aware +of it-- that you are not + +following fast enough to +keep up with the motion + +of the vertical bar, +you order the eyes + +to move faster, +faster, and faster, + +and faster and faster, +and it practically + +runs away like crazy. + +And it still-- of course, +because the eye is + +immobilized-- hasn't been able +to catch up to the moving bar. + +So this further highlights the +importance of this mechanism. + +And it has to be a closed +loop system, obviously, + +for it to work properly. + +So there's a +feedback telling you + +whether you had correctly +tracked something. + +OK, so now I come to +the last point today, + +which is now the mechanism +that is involved in the motion + +analysis of accessory +optic system. + +I'll talk about +this only briefly, + +because this is going to +be part of your paper. + +All right, now, they +remarkable discovery + +that was made-- +amazing discovery-- + +was that when people recorded +from the cells of Dogiel, + +they found that these cells +come in three different types + +with three different axes of +orientation, these three axes. + +And when that was +first found, people + +said, what on earth is going on? + +Why would we have +three like that? + +I would have thought +we'd have four, + +vertical and horizontal +at least, or something. + +So this was really puzzling. + +But then they began to +do some more experiments. + +And they made a truly +remarkable discovery. + +And their discovery +is shown here + +in a summary diagram of +the accessory optic system. + +OK, here are these +cells of Dogiel + +with the three axes of +direction selectivity. + +They respond to rather +slow motion velocities. + +So what happens +here-- I'm not going + +to go into detail, because +you're going to, as I say, + +report on this. + +But let me tell you +about the essence of it. + +The cells of Dogiel project into +the so-called terminal nuclei. + +And then they project +up to the cerebellum. + +And from the cerebellum, +there's a projection down + +to the vestibular nuclei. + +And then it was found, +as it was known already, + +that the semicircular +canals come + +in three orientations +which are the same as those + +of the orientations of +the cells of Dogiel. + +And so then they feed into +the ocular motor system + +to move the eyes so as to +keep the eyes in accurate + +contact with whatever +you're intending to look at. + +So that is the very essence +of the accessory optic system. + +And I just thought +this will help you + +in putting your paper together. + +All right, so now I am +ready to summarize for you. + +First of all, motion +has been classified + +into several different types +that include planar, circular, + +and radial. + +And one thing we talked about +earlier that I mentioned here, + +but I didn't mention +in this presentation-- + +when we talked about +depth perception, + +we talked about motion parallax. + +That's a very important +aspect of motion analysis. + +Then secondly, the +majority of cells in V1 + +and most cells in MT are +directionally selective, OK? + +And an addition which +I mentioned earlier + +is that they also show +velocity selectivity. + +Some V1 cells respond +to different directions + +of movement for light and dark +edges, like the S2 type cell + +I showed you. + +And some cells are sensitive +to differential velocities + +of movement, which +I didn't show. + +Then the accessory +optic system that + +begins with the retinal ganglion +cells of the cells of Dogiel + +form three axes of +direction selectivity + +that correspond +to the three axes + +of the semicircular canals. + +And they are involved in +generating pursuit eye + +movements for image +stabilization. + +Then one of the most important +tasks of motion analysis + +is motion parallax, +as it provides + +information about depth. + +Motion cues can provide +important information + +for object recognition, +often referred + +to as structure for motion. + +And stationary +stimuli that flicker + +with various temporary signals +induce apparent motion, + +of which I showed you +a lot of examples. + +And then we talked about +metacontrast masking, + +which is a phenomenon +that occurs + +when two stimuli share contours. + +And when they're presented with +an interval which corresponds + +to apparent motion, you tend +not to see the first one. + +Lastly, brightness masking +arises with overlapping stimuli + +appearing in rapid succession. + +And this does not occur with +interocular presentation, + +proving that it's a +record of phenomenon. + +And it has to do with the fact +that the velocity with which + +a stimulus activates the retinal +ganglion cells and hence, + +of course, the cortex, is much +much slower with dim stimuli + +then with bright ones. + +And so bright +stimulus, in a sense + +overtakes the responses +to a dim and weak stimulus + +when the two successive +presentations are very rapid. + +OK, so that's the +end of it here, OK? + +And I'll show you one +more motion effect. + +Ready? + +All right, so that is +the story for today. + +And next time, +you're going to have, + +as I said, a rapid +summary of what + +we have covered in the +first half of this course. + +And then the following +Wednesday, we + +are going to have the multiple +choice exam for the midterms. + +OK, thank you kindly. \ No newline at end of file diff --git a/oXsC9bjMJA4.txt b/oXsC9bjMJA4.txt new file mode 100644 index 0000000000000000000000000000000000000000..d6136785a42aa9d82ec7247f513f710e9211338d --- /dev/null +++ b/oXsC9bjMJA4.txt @@ -0,0 +1,2672 @@ +The following content is +provided under a Creative + +Commons license. + +Your support will help +MIT OpenCourseWare + +continue to offer high quality +educational resources for free. + +To make a donation or to +view additional materials + +from hundreds of MIT courses, +visit MIT OpenCourseWare + +at ocw.mit.edu. + +HONG LIU: And let us start. + +So let me again start +by reminding you + +what we did before. + +So consider, say, we have +a scalar field in AdS + +So let me just summarize +what we did before. + +So consider, say, +a scalar field, + +phi, in AdS and with mass +times square, so with mass + +squared given by m +squared, then we know, + +when you go to the +boundary of AdS-- so let's + +take z goes to 0-- +then phi will have + +the following +asymptotic behavior. + +So these are the two independent +modes of phi [? to ?] infinity. + +Of course, there are higher +order corrections in z. + +And this delta is +given by 1/2 d plus nu. + +And nu is given by +this square divided + +by 4 plus m squared r squared. + +So this is the behavior. + +And so this phi is assumed to +be dual to some boundary, scalar + +operator. + +And then all of +those quantities, + +on the gravity side, they +all have counterparts + +on field theory side. + +For example, the delta, +which, essentially, + +is a function of mass, +then, essentially, it's + +the scaling dimension of O. +It's a scaling dimension of O. + +And this Ax +essentially translates + +into the source for phi. + +Or you can consider the +momentum space version, say, you + +can do Fourier transform, +Ak, then go to the phi k. + +And then we also showed, last +time, that the 2 nu times Bx + +is actually related to the +expectation value of O. + +And again, there's a +momentum space version of it. + +So you can just +Fourier transform, then + +become O k and Bk. + +And in particular, +in the example, + +we can see the +scalar field example. + +In particular, in the +example, you can see that. + +So we derived this relation +from a free scalar field. + +but you can actually show this +relation is actually generally + +true at non-linear level. + +So if you also include the high +orders, et cetera, so including + +non-linear dependence on +phi, actually this relation + +remains true. + +But due to the time, we +will not go into that. + +The proof is actually +not very difficult. + +So you can see that the +free scalar examples-- + +so, in the example, we +can see that actually + +the B-- so in momentum +space, the B is actually + +proportional to A. If you +remember what we did last time. + +So in other words, +this one-point + +function-- so B is related +to the one-point function. + +So in other words, +the one-point function + +it's proportional to the source. + +So this is the standard story. + +Say all x equal to 0 +when phi equal to 0. + +So if you don't have the source, +then this one-point function + +is 0. + +So you don't have a spontaneous +expectation value for the O. + +And now the fact that +B is proportional to A, + +so this is just reflects that, +in the presence of the source, + +then, of course, the +expectation value-- so + +let me write it in momentum +space for simplicity. + +Then we're no +longer [INAUDIBLE]. + +Assume the source is small, then +you can expand the expectation + +value in power series of phi. + +So to the 0, so that +would be phi, and then + +phi squared, et cetera. + +So at linearized +level, say we just find + +O k is proportional to phi k. + +We just find that O k is +proportional to phi k. + +And the proportional +constant is, in fact, + +the two-point function. + +So at linear level, so O k would +be just proportional to phi k, + +but the proportional constant +is just the two-point function. + +So the reason is very simple. + +First, let me write +down the definition + +of this two-point function. + +So GEx in coordinate +space is defined + +to be O x of 0, because +of translational symmetry, + +so I can put the +other point to be 0. + +So this is only the +function of one variable, x. + +And then you can +Fourier transform, + +and then you get GEk. + +So this is how we +define the GEk. + +So to see that this +is true, you need + +to remember that +the GEk is given + +from taking the generating +functional, delta phi k + +and delta phi minus k, then +you set phi equal to 0. + +So this is the definition +of the two-point function. + +And then next, you can see +that the [? one derivative ?] + +of phi minus k-- so you can see +that this takes 1 derivative + +on phi minus k. + +That just gives you +the one-point function + +in the presence of phi +and then delta phi k. + +And take phi equal to 0. + +So I just evaluated +this derivative. + +So if you take this +generating functional, + +take one derivative, we +just get one-point function. + +And then this is the +other point function. + +Then at the linear +level-- so if O k + +is linear in phi k, of +course, taking the derivative + +is just the same as dividing it. + +So this is the same. + +So continue over. + +This is the same just as to +the phi k divided by phi k + +at the linearized level. + +And then so this tells you +that this pre-factor is just + +the two-point function. + +And so we can now write a +two-point function explicitly + +in terms of B and A, +so this is just given, + +because this is 2 nu Bk. + +So this is just given by that. + +So this is just a quick +summary of what we + +did at the end of last lecture. + +So that's how you can find +the two-point function. + +So you work out what +B is, what the A is, + +and then the rest of them +is the two-point function. + +And the way we work out the +B and A is the following. + +So at the linearized level, when +you solve the equation motion + +for phi, then you impose +the boundary conditions + +at infinity, A should +be equal to phi. + +But then there's +another condition + +being proposed to make +sure the phi is actually + +regular in the interior. + +So the regularity +condition, there's still + +a relation between +A and B. And then + +that leads to this +two-point function. + +Any questions on this? + +Is everything clear? + +Good. + +So now let's consider the +higher-point functions. + +So this is, in principle, +straightforward to do. + +Because, recall, that the +log CFT phi, this generating + +functional, in the +field theory, is just + +given by the classical +action on the gravity + +side, which is the boundary +condition given by phi. + +You're solving the +classical equation + +motion, the initial action. + +Then you just, as +we did earlier, + +you just solve the +equation motion for phi + +to the [? linear ?] order. + +And then you validated +the initial action. + +Then you can express, +for example, this SE + +in power series of phi. + +And then the quotient for +the power series of this phi + +then just gives you +correlation functions. + +So the principle of this +is straightforward to do. + +We know how to solve the +classical equation motion. + +We know how to plug +back into the action, + +and then you are done. + +So just to be able +to be more specific, + +let's consider an example. + +Let's just consider +two examples. + +Again, let we just +consider the scalar field. + +Now, I add the linear term. + +For illustration, let me +give you two examples. + +And so a very important thing is +that in our set-up, the lambda, + +this cubic quotient is +proportional to kappa. + +And then if you translate +into the field series side, + +this is 1/n. + +So remember, for anything +in the gravity action, + +you always have the 1 +over kappa squared, 1 + +over G Newton before +[INAUDIBLE] action. + +And then when we try to +change phi into canonical + +normalized, and then +you rescale phi. + +And the consequence is that +this cubic term or quartic term, + +then they will have quotients +proportionate to kappa. + +And according to this rule, if +you have a quartic term, then + +that will be proportional +to kappa squared, et cetera. + +And so the key is that as +far as [? phi is ?] order 1, + +then you can actually treat +those higher-order terms + +by perturbation because +the quotient is small. + +And of course, you can +also consider the situation + +in which phi is +large, and then you + +have to solve the full +nonlinear problem. + +Then you cannot do a +perturbative expansion. + +You have to do the problem. + +So for our purpose, +if you want to find + +the higher-point +function for phi, + +then you need to +solve this equation. + +So box phi is just +a Laplace operator. + +I just save time. + +So you need to +solve this equation. + +And with the boundary condition +still the boundary condition, + +the boundary value of capital +phi to equal to this phi x. + +And let me call +this equation star. + +So as I said, because +this lambda is small, + +you can actually try to +solve this equation just + +perturbatively in lambda. + +And essentially, you're solving +it perturbatively in this phi, + +because everything, in the end, +will be expressed in this phi. + +So one can solve +star perturbatively + +in phi, which is the +boundary value of the field. + +And say phi c, you can expand it +as phi 1 plus phi 2, et cetera, + +so the classical +solution expanded. + +And this linear in phi. + +And this is quadratic +in phi-- and et cetera. + +And then when you plug +back this into the action, + +then you find on +the initial action + +can also be expanded in +power series of this phi. + +So you will have S2 phi plus-- +started with quadratic order-- + +and 3 phi, et cetera. + +And then the quotient here gives +you the two-point function. + +And then quotient here gives +you the three-point function. + +And the quotient here gives a +four-point function, et cetera. + +I hope the procedure is clear. + +Any questions regarding this? + +So even though this is +very straightforward + +to do, conceptually, +but in practice + +that it not what we would do, +because this is a very tedious. + +It's very tedious. + +And our knowledge of +quantum field theory + +gives us something much +simpler to deal with. + +Because this, essentially, +if you think about it, + +is not very different from +doing a correlation function + +calculation, just in the +flat-space quantum field + +theory. + +And there, whey you +calculate the Green function + +in flat-space-- in +flat-space quantum field + +theory, what do you do? + +Do we try to solve the classical +equation motion and you iterate + +the equation? + +What do you do? + +AUDIENCE: Draw a diagram. + +HONG LIU: Yeah, you +use Feynman diagrams. + +So here, it's exactly +the same thing. + +So here it's much easier if you +just do the Feynman diagrams. + +So let me first remind you +what we do in the flat-space. + +So let's now go to +the field theory + +one, standard, ordinary +flat-space QFT. + +So now let's consider the lambda +phi cubed theory in flat-space + +Just the same theory now +using the flat-space. + +Let me call this star-star. + +So essentially, let's +just consider star-star + +in flat-space, now in +flat Euclidean space. + +So if we are given a +field theory like that, + +so how would you calculate the +following correlation function? + +Say, suppose I want to +calculate phi x1, phi xn. + +So now this x1, xn, they're +just flat-space coordinates. + +To distinguish them, +let me just call y1, + +yn, just not to confuse +about the AdS coordinate. + +So in flat-space +with y, y mu, OK? + +In flat-space with +coordinate y mu. + +So now suppose you want to +calculate the correlation + +function for this. + +What do you do? + +So what do you do? + +It's easy. + +What you do is that this +theory has a propagator, G, + +[? with ?] [? arrow ?] +propagator. + +And also, this theory +have a interaction vertex, + +which is controlled by lambda. + +And then, when you calculate +such endpoint functions, + +you just fix your endpoint. + +So now remember, this is +slightly different than what + +you would normally do +in field theory one, + +because, here, we're +doing coordinate space + +rather than momentum space. + +In field theory one, you're more +used to doing momentum space. + +So here what you do is that you +fix y1, y2 y3, extends to yn. + +So this is essentially the +location of your insertion, + +of your field insertion. + +So essentially, imagine +there's a source there. + +And then you just connect +all the extended points + +by propagators and with these +kind of interaction vertices. + +So for example, you can have +something like this, et cetera. + +And this connects to +some boundary point, + +some other point, +et cetera-- say y's. + +And this also have lines. + +We just draw all +possible diagrams, + +and you calculate that diagram. + +You calculate those diagrams, +and they give you this thing. + +And essentially, the +diagrams automatically + +give you the +iteration procedure. + +So now, back to +AdS, essentially, we + +can just do exactly +the same thing. + +Just remind yourself +of the procedure + +of calculating this and what +we are going to do here, + +and you easily +convince yourself. + +So it requires a couple +of minutes' thinking, + +but we'll leave it to yourself. + +Actually, that procedure is +no different from just doing + +the calculation like this. + +Of course, the +difference is that now we + +are in the curved spacetime +rather than flat spacetime. + +But there's another +major difference. + +So here, the source all lies in +the interior of your spacetime, + +where you inserted the operator. + +But here, all the source, phi +x, they lie at the boundary. + +That's, essentially, +the only difference. + +So if I just schematically-- +so this is AdS. + +This is the boundary. + +And essentially, all the points +are lying on the boundary, + +like we have x1, x2. + +So let's consider +four-point function. + +Because each one of them is +labeled by the boundary point. + +And then for the four-point +function, you just connect. + +So you can connect +the diagram like this. + +Again, you have +the vertices, which + +is the [? cube ?] of vertices. + +But your endpoint is all +lying on the boundary. + +So this structure also +tells you, actually, + +there's two types +of propagators. + +Because one type of propagator +connects the two bulk points. + +And then there's this +kind of propagator + +which connects the bulk point +into the boundary points. + +So this is the difference, +one major difference, + +from the flat-space case. + +So here, all the +propagators are the same. + +So here, the difference +is now, you also + +have propagators which come +from boundary to the bulk. + +So in this case, there are +two kind of propagators. + +Here, you have two +type of propagators. + +So one type of propagator +is what we call + +the bulk-to-bulk propagator. + +Somehow this is going up and up. + +OK, I lost some +blackboard space. + +So this the complete +analog, this + +is the precise counterpart +of the flat-space propagator. + +So this connects two points, +z, x, z prime, x prime. + +So I still use the +notation that z is the bulk + +[INAUDIBLE] direction. + +And the x is along the +boundary direction. + +And this bulk-to-bulk will +satisfy the standard Laplace + +equation just as in flat-space. + +So this gives you +the delta function. + +Let me just express it, z minus +z prime delta x minus x prime. + +So this is a complete analog +of the standard flat-space + +propagator. + +It's just now in +Anti-de Sitter space. + +So this is a counterpart in AdS +standard flat-space propagator. + +So in particular, +so as a propagator, + +this should be normalizable +in either z or z prime, + +so when you take +them to the boundary. + +So more explicitly, for +example, the z at z prime, + +x prime, should scale as z +prime to the power delta, when + +you take z prime goes to 0. + +And of course, this +should also be regular. + +We should not have singularities +as z goes to infinity. + +They should also be regular. + +So essentially, these +condition will precisely + +define those propagators. + +But the idea is we +also, because the source + +lies on the boundary, because +of this boundary condition, + +we also have so-called +boundary-to-bulk propagators. + +Actually, the standard +in flat-space one, + +it propagates the field from +one point to the other point. + +So that's why there's +a delta function here. + +So the standard story, +there's a delta function here. + +And you propagate +the field starting + +from this point to that point. + +So this boundary-to-bulk +propagator normally is written + +as k z,x, but the second +index only has x prime, + +because this is when you take +the boundary point to a bulk + +point. + +A boundary point, of course, +there's no z anymore. + +So z prime is 0 here. + +You don't need to write it. + +And this boundary-to-bulk +propagator, + +again, should satisfy +the Laplace equation. + +But now the key point is +that, on the right-hand side, + +because there's no bulk +source, so the right-hand side + +should be 0 rather than +the delta function. + +So that delta function is +due to the bulk source. + +But we have to make +sure this k have + +the right +non-normalizable boundary + +conditions, so you +have the right boundary + +condition to the boundary. + +So this when it approach to +the boundary, as z goes to 0, + +should be like z d delta, +delta x minus x prime. + +So the k satisfies the Laplace +equation without a source. + +But when you take this +propagator to the boundary, + +then it should give you the +non-normalizable boundary + +conditions, because you +should approach a source. + +And the delta +function is put here. + +So if you write, +say, a bulk field, + +which is sourced by some +boundary source, say k z, x, + +x prime times phi x +prime, and then this + +will have right +boundary condition + +that the phi x, z goes +to z d minus delta phi x. + +So this boundary-to-bulk +propagator + +does not have a +source in the bulk + +but does have a source +in the boundary, + +non-normalizable +off in the boundary. + +So now with this two +propagator, then the story + +is just actually as +in the standard way + +you obtain the Green functions. + +It's just really no different. + +So let me just summarize +what we have discussed. + +The boundary +endpoint function can + +be obtained by, essentially, +endpoint function of the phi + +field in the gravity side-- +let me write it here-- just + +related to the endpoint +function of the gravity field + +on the gravity side, with +all these points, x1, xn, + +they're lying on the boundary. + +This side is treated as +ordinary field theory. + +Then compute this endpoint +function of your field + +but just put the +field on the boundary. + +And then that would just +give you the AdS correlation + +functions. + +Yeah, and then you just +need to distinguish + +two types of propagators, +a bulk-to-bulk propagator + +and bulk-to-boundary propagator. + +So any questions regarding this? + +AUDIENCE: Now, here, +[INAUDIBLE] d minus delta. + +Right there, the G goes to +[? d ?] phi in the delta. + +HONG LIU: Yeah. + +AUDIENCE: But why +aren't they different? + +HONG LIU: It's because +this must have a source. + +So the boundary-to-bulk +propagator-- + +you propagate the source, +from the boundary to the bulk, + +so that means that field +must have the right boundary + +condition. + +So that's the reason for this. + +We must have non-normalizable +boundary conditions. + +And that propagator is just the +standard flat-space propagator. + +Of course, it's +always normalizable. + +And in the flat-space, +when you construct + +a propagator, of +course, it's always + +used in a normalizable +wave function. + +AUDIENCE: This is +that's non-normalizable? + +HONG LIU: No, this +is non-normalizable. + +This is designed so that +you have the right boundary + +condition. + +So this is designed so +that you can propagate + +just as in flat-space. + +If you have phi at +this point, and then + +you can propagate to the +other point by convolution. + +And of course, when you write +down the bulk field phi, + +in general, you only +construct them out + +of the normalizable modes. + +Any questions? + +Good. + +So now let me make some remarks. + +So here, this +procedure of iterating + +the classical +equation of motion, + +solving the classical +equation of motion, + +then iterating the +action, of course, + +again, from our experience +with quantum field theory, that + +only gives you the +tree-level diagrams. + +So if I really write +the bulk path integral, + +so Z CFT phi, then, in +the same classical limit, + +it can be written +as Z gravity, which + +is phi with the right +boundary condition. + +And then on the gravity side, +at semi-classical level, + +we can actually write down the +path integral for this gravity + +partition function. + +So that's what we +discussed before. + +And then at the leading +order, in performing this path + +integral, of +course, you just get + +what we have been doing so far. + +You just evaluate it at +the classical solutions. + +But in principle, you can +also see the fluctuations. + +So this is the +fluctuations around, say, + +the classical solution, phi c. + +And then the action +for the fluctuations + +is just given by phi c plus phi. + +The minus, of course, +is the classical action. + +So we just expand +around the phi c. + +So if we expand this, +the leading order + +would be quadratic in small phi. + +I should now quote small phi. + +Maybe let me quote chi, because +that is the same as that phi. + +So this chi is the small +fluctuations around the phi c. + +So if you expanded this +in chi, the linear order + +is 0, because phi c satisfies +the equation of motion. + +So this will start in quadratic +order and then cubic order, et + +cetera. + +So you validated the +quadratic order as a Gaussian. + +And then that's the +one-loop diagram. + +And then if you go +to higher orders, + +then it'll give you +higher-order diagrams. + +So if you now include +the fluctuations, + +so the SE phi c, which +is a classical action. + +This encodes only +tree-level diagrams. + +And when you include +the fluctuations, phi, + +the fluctuations, chi, and +then this corresponding + +to include loops. + +So again, the whole +procedure can be captured + +by the Feynman diagrams. + +So the advantage of +the Feynman diagram + +is actually there's a natural +generalization to the loop + +diagrams. + +And then just include +the loops here. + +For example, here, you can +do something like this. + +Now you can also have +something like this. + +So that's, of course, +one and two, including + +the fluctuations, are +under the saddle point, + +are including the fluctuation +around the saddle point. + +Any questions +regarding this point? + +Good. + +Yes? + +AUDIENCE: So when people draw +these like so-called Witten + +diagrams, where they +draw up like this circle. + +HONG LIU: Right. + +AUDIENCE: Is that +basically what we're doing? + +HONG LIU: Yeah. + +Yeah, right. + +Yeah, so let me just +explain one thing. + +In the Euclidean, I have been +drawing the ideas like this. + +So this is z equal +to 0, et cetera. + +So in the Euclidean signature, +as you will do in your PSet, + +then this z equal +to infinity, you + +can argue is actually +a single point. + +So let me just write +down the metric. + +So the metric is R +square, z square. + +When you go to +Euclidean signature, + +you just have dx squared. + +So this is a full +Euclidean metric. + +So there's something +interesting about the difference + +between the Euclidean +and Lorentzian, + +even though, from this +picture, it's roughly the same. + +So if it's equal to +0, you go to z notch. + +And then in the Euclidean +case, you can actually + +show that z equal +infinity, even though, + +[? naively, ?] you still +have a full Euclidean plane, + +but you can argue, actually, +that the whole thing is + +actually a point. + +And you can roughly see, when +you go to z equals infinity, + +the overall factor goes to 0. + +So essentially, the whole +space shrinks to a point. + +The whole space +shrinks to a point. + +So in Euclidean, if +it's equal to infinity, + +it's essentially a point. + +And then topologically, this +is equivalent to having a disk. + +Topologically, the whole +space is just disk. + +And the z equal to infinity +is one point on the boundary. + +And then the other +is z equal to 0. + +And so this is the +interior of the space. + +Yes? + +AUDIENCE: So in other words, the +entire perimeter of the circle + +is identi-- + +HONG LIU: It's the boundary. + +AUDIENCE: [INAUDIBLE]. + +HONG LIU: Yeah, this +is the boundary. + +Essentially, you can imagine, +each point here is R to d. + +Then you add the +point at infinity, + +and then it becomes a sphere. + +AUDIENCE: [INAUDIBLE]. + +HONG LIU: Yeah, it +becomes a sphere. + +And then the whole thing +becomes like a disk. + +So normally, when people +will draw-- so topologically, + +you're creating a +disk, just like this. + +Then people will just +draw diagrams like this. + +Yeah, I draw diagrams like this. + +AUDIENCE: If you add a +single point to the boundary, + +that single point is equal to +infinity to the boundary, which + +is z equals 0? + +HONG LIU: Sorry? + +AUDIENCE: You mean that you +have a point that [INAUDIBLE]. + +HONG LIU: Yeah. + +Yeah, this point turns +out, it can actually + +lie on the boundary. + +AUDIENCE: But then, on the +boundary, the value of t + +is not continuous. + +HONG LIU: Hm? + +Yeah. + +So this is due to the +coordinate choice. + +It's just this coordinate +becomes singular at that point. + +You can rewrite it. + +Yeah, the simplest thing is that +you rewrite these [INAUDIBLE] + +coordinates to the coordinate +which has a parameter that has + +a boundary really as a sphere. + +And then you will see it. + +Because when you write +the sphere as a plane, + +then this one point +becomes singular. + +This is just the standard story. + +Just that coordinate +choice is singular. + +Any other questions? + +Good. + +So this is the first remark. + +The secondary +remark is that this + +is a little bit of an +unusual correlation function. + +So this is the bulk +correlation functions, + +but with all points +lying on the boundary. + +So the counterpart or +just the exact analog + +of standard flat-space +correlation functions in AdS-- + +you can see the end +bulk point and look + +at its correlation functions. + +So this then will be really just +bring you to the standard QFT + +one correlation functions. + +Then you have endpoints, z1, +x1, or in the bulk, z2, x2, et + +cetera. + +And then you just draw a +diagram between them, et cetera. + +The area propagator +here would be + +just bulk-to-bulk propagator. + +There's no boundary-to-bulk +propagator. + +There's no boundary-to-bulk +propagator just + +all bulk-to-bulk propagator. + +So this is a complete analog of +your ordinary flat-space Green + +functions. + +But we can easily imagine that +this correlation function must + +be related to those +correlations functions + +if you just take those +points to the boundary. + +So it's natural to expect, say, +those correlations functions, + +since they're at +the boundary, must + +be related to those kind +of standard correlation + +functions, in which you would +take the point to the boundary. + +So those, somehow, in the +end, must be the same. + +So if I take those +points to the boundary, + +I should recover that guy. + +So indeed, this +relation is true. + +And you will work it out +yourself in the PSet. + +You see, the only +difference is the following. + +When you take those points +to the boundary, what you get + +is the boundary limit. + +So now let's imagine you take +those points to the boundary. + +Because here, it's +all bulk propagator. + +So those propagator, which +connect to the boundary, + +would be the boundary limit +of the bulk propagator. + +And then, it just +boils down to, what + +is the relation +between the boundary + +limit of the bulk +propagator and this boundary + +to the bulk propagator? + +So the above relation-- let +me just-- I'd rather just + +call it a number. + +So this star-star-star +just boils + +down to the relation +between the k + +z, x, x prime, which is our +boundary-to-bulk propagator, + +and limit z prime goes to +0, G x, z, x prime, z prime. + +So you will find +that these two guys + +are proportional to each other. + +And once you extract out +that proportional factor, + +then you just relate them. + +So this is just another +way to calculate. + +Because this is the bounty +correlation function. + +So this is the boundary +correlation function. + +So this is related to the +CFT correlation functions. + +And then you can also calculate +the CFT correlation function + +just by taking the limit of +the bulk correlation functions. + +So this you will work +out a little bit. + +Yeah, you will work out the +precise relation in your PSet. + +Maybe some of you have +looked at it already. + +So any questions on this? + +AUDIENCE: What is the +advantage of maybe + +using another to express it? + +HONG LIU: Yeah, just different +ways of calculating things. + +And of course, normally, +I have many different ways + +to calculate things. + +Some of them may be +convenient this way. + +So of them may be convenient +for that purpose, et cetera. + +It depends. + +Normally, we just +directly are using + +the bulk-to-boundary propagator. + +If you just do the calculation, +the bulk-to boundary propagator + +actually is simpler. + +But sometimes, for certain +conceptual questions, + +this actually becomes simpler. + +So now let's look +at Wilson loops. + +So how do you calculate the +Wilson loops using gravity? + +So in the gauge +theory-- so I assume + +you have already done the +QFT II and the gauge theory? + +In the gauge +theory, we also know + +it's essentially one of the +most important observables. + +The Wilson loop is normally +defined in the following way. + +So now I will +explain my notation. + +So let me also add +in subscript r here. + +So c is a closed path. + +So this is defined +for closed paths. + +And A mu is a matrix. + +So we can see the +[INAUDIBLE] in gauge theory. + +A mu is a matrix, writing +the standard away, + +in terms of the generator, +in some representations r. + +So this is in some +representations. + +So this is just the +generators of the gauge + +group in some representation, +which we'll call r. + +And P is the path ordering. + +So in general, you can choose +any representations you want. + +But often, we choose r, say, +in fundamental representations. + +For example, that's +normally what we do, in QCD, + +in fundamental representation. + +But you can choose it to +be any representation. + +So the physical meaning +of this, so this operator, + +by definition, is +gauge invariant, + +because of this trace. + +And need the path ordering, +because you have a matrix here. + +And the matrix, at different +points, don't commute. + +So you need to specify ordering. + +And so you just specify it +by the order of the path. + +And so the physical +meaning of the Wilson loop, + +so this is essentially the +phase factor associated + +with transporting an +external particle, in a given + +representation, say, in r +representation, along c. + +So you transport the +particle along some path. + +And you come back +to the same point. + +Then you find that that +phase does not necessarily + +go back to 0. + +And so this is a +nontrivial phase. + +It essentially tells you there's +a nontrivial gauge field there. + +Yeah, so this provides a +probe of the gauge fields. + +Yes? + +AUDIENCE: I know +that people talk + +about-- I know that it's +somehow and observable. + +But is it actually observable ? + +Can you actually +do an experiment + +to measure this phase? + +HONG LIU: I don't think so. + +Ha. + +It depends. + +Yeah, in some +situations, you can. + +Let me mention something +else, then the answer + +to this question will be seen. + +So the simplest case +would be the W c, just + +the single-point function +of W c, say, in a vacuum. + +So this is the +simplest observable. + +But of course, you can also +consider the generic, say, + +a large number, several +[? routes ?] in some general + +state, say, for example, +[? finite ?] [? telemetry ?], + +et cetera. + +So these are the +typical observables. + +So now let me emphasize +this external. + +So this external +is very important. + +So normally, by calling +something external, + +we mean that this particle +has infinite mass. + +It's infinitely heavy. + +And the reason we want +it to be infinitely heavy + +is because only for +heavy particles, + +in principle, you can +localize the lower path. + +Then you can make mathematical +sense of the precise path. + +Otherwise, if it's a +fluctuating particle, + +then you can not specify a +path-- yeah, ambiguously. + +So when we say, an +external particle, I always + +say a particle which is assumed +to be infinitely massive. + +And also, I've +introduced terminology. + +When this r is in the +fundamental representation-- + +yeah, maybe not right here. + +When this r is in the +fundamental representation, + +we'll call the corresponding +particle a quark. + +If it is in the +fundamental representation, + +I will call it a quark. + +I will often just consider the +fundamental representation. + +In the phase factor, where +we're corresponding to, + +you transport a quark. + +So one of the very often used +loops is a rectangular loop. + +So this is along some +spatial direction, + +so this is the time direction. + +So let's say the +spatial direction is L, + +and the time direction, +using the length, + +is T. So imagine you +have a loop like this. + +So normally, we can +see that the T, say, + +the length of the loop +in the time direction, + +is much, much +greater than the L. + +So in such a limit, +then, essentially, + +you can ignore the +contribution from this side, + +from these two short sides. + +So in the limit, in which +this T goes to infinity, + +to leading order, you can +ignore the short side. + +And then you can +think of this loop + +when it just has a particle-- +so this is a particle moving + +forward in time. + +This is a particle +going backward in time. + +Then you can consider this as +a particle and an anti-particle + +moving forward in time. + +So in this case, we can +argue, on general grounds, + +that this will just, +to leading order, + +will give you something iET. + +And this e, it just +can be interpreted + +as a potential energy between a +single quark and an anti-quark. + +So in this example, +this is the same. + +In this case, you may be able +to measure this Wilson loop, + +because if you can +measure-- experimentally, + +you may be able to measure +this energy between the two + +particles. + +And then, essentially, you can +say, I have measured the loop. + +And then you can compare with +the prediction of the loop. + +So again, in order to make +this interpretation make sense, + +this particle having infinite +energy is very important. + +And again, only for the +very heavy particle, + +you can really +localize them, and then + +talk about the potential energy +between these two particles. + +Otherwise, if they +fluctuate a lot, + +then it's hard to +make it precise. + +So now the question is how do we +calculate this quantity in AdS? + +When I don't put an index +here, I just mean that this + +the fundamental representation. + +The question is how we do that. + +So in order to +answer this question, + +we first need to +understand how to introduce + +a fundamental external particle, +external quark in the N + +equals 4 super +Yang-Mills theory. + +So how to introduce a +fundamental external quark + +in the N equals 4 super +Yang-Mills theory. + +So we know, as we +discussed before, + +that everything in the N equals +4 super Yang-Mills theory, so + +all fundamental fields, +all the fields in the N + +equals 4 super +Yang-Mills theory, + +they are in a joint +representation. + +There's nothing in the +fundamental representation. + +Everything is in the +joint representation. + +So first we need to introduce +a fundamental object, + +an object we transform under +fundamental representation. + +After we have done that, then we +need to translate that quantity + +to the gravity side. + +And then we understand how +the gravity description + +of such an external particle. + +So this is easy to do. + +This is easy to do. + +So let's first think about +how to do this in the N + +equals 4 super +Yang-Mills theory. + +And then this is a +very intuitive by using + +this [INAUDIBLE] picture. + +So we know the N equals +4 super Yang-Mills + +theory comes from low-energy +theory of N D3-branes. + +They come from the low-energy +theory of N D3-branes. + +So how do we introduce +an external particles? + +So now let's imagine, +consider N plus 1 of them, + +and let me separate +one from the rest. + +So this is still N, +separate one from the rest. + +So then there can be open +string connects between them. + +So suppose I separate +them by some distance, r, + +in the transverse +direction to the D3-brane. + +So as we described before, such +as a separation breaks the SU N + +plus 1 symmetry of +the D3-brane SU N + +and then a single +U1 of this 1-brane. + +In particular, such +an open string-- + +so let's look at the endpoint. + +Then the endpoint of this +string can only have indices. + +Because this is a +single stream, one + +end ending on the other side. + +There's only one index. + +And here, they can only +have N possible index. + +So such a fundamental +string transforms + +in the fundamental +representation. + +So from the point of view +of this SU N gauge theory, + +this is a quark. + +So this endpoint is a quark. + +So this is a quark. + +And the mass of this +quark is equal to-- so let + +me call the mass capital +M-- is equal to r, + +the length between them divided +by tension of the string. + +So this we have derived before. + +So this just gives you +the mass of the quark. + +So when you separate one +D-brane from the other, + +so you have introduced +this quark, with a mass. + +So now let's consider that +there's no low-energy limit + +[INAUDIBLE]. + +So in the low-energy +limit of [INAUDIBLE], + +so we want to keep this +quark, so there, of course, + +you want to take +alpha prime go to 0. + +But we want to keep this quark +in the low-energy spectrum, + +because we want +this to remain in N + +equals 4 super +Yang-Mills theory, + +because we want to +introduce this particle. + +So in this low-energy limit, +when we take off a prime, + +go to 0 limit, we also want +to take, at the same time, + +r goes to 0 limit, so that this +mass term, r divided by alpha + +prime, will remain finite. + +Then that means +this will remain, + +this particle, such kind of +fundamental representation, + +will remain in the N equals +4 super Yang-Mills theory. + +Because other modes are massive. + +And then when alpha +prime goes to 0 limit, + +it goes to infinity. + +And under those modes, +we will remain with the N + +equals 4 super +Yang-Mills theory. + +So now let's see what +happens on the gravity side. + +So here, you will need to +fill in some details yourself. + +I'll only tell you the answer. + +On the gravity side, you +have this N D3-brane. + +They have one brane which +[? is ?] [? r ?] separated from + +this N D3-brane. + +And they're separation +is such that, when + +you take off alpha +prime and go to 0 limit, + +their ratio is finite. + +Now, in the gravity +side, you have + +to take this so-called +near-horizon limit, + +with taking into account. + +So what you find in the +gravity side is that, + +as before, that N D3-brane now +disappeared into r equal to 0. + +Remember, r equal to 0 is that +infinite proper distance away. + +And now we are using +this r coordinate. + +And when we take +this low limit, we're + +using this r coordinate +rather than this z coordinate. + +So in that case, you +have i equal infinity. + +Then the brane, essentially, +goes to r equal to 0. + +which has infinite +proper distance + +away from any finite r. + +So now this is an +exercise for yourself just + +to repeat our previous argument. + +Then you will find that +in this regime, when + +you take alpha prime +go to 0, this r finite, + +this D3-brane does +not disappear. + +The single D3-brane +will remain in the AdS. + +So the difference, from +our previous story, + +is that, in addition +to the AdS, now + +you have an additional +D3-brane at some point in S5. + +Because D3-brane is in +some transverse direction, + +which now become S5. + +So you have a D3-brane, +which is parallel + +to the boundary coordinates, +but sitting at one point in S5. + +And I think this +picture is reasonable, + +but you should check yourself. + +Because in this regime, this +D3-brane does not go away. + +And a remarkable thing +you will check yourself + +is that when you take +the [INAUDIBLE] limit, + +in this picture, +this is flat-space. + +Then you have this formula. + +And now, when you take this +limit, this now become AdS. + +Now, this AdS at some radius +r, controlled by this r. + +And now you can +check one nice thing. + +In AdS, if you consider a +string, straight string, + +from this D3-brane all +the way to r equal to 0, + +which is this +string, this string + +has exactly the same mass. + +So the mass is equal to r +divided by 2 pi alpha prime-- + +also in AdS5. + +So this is a consistency check. + +Because when you take the +low-energy limits, of course, + +you should not change the mass. + +The mass of the string +will not change. + +The only question is whether +it will stay in the spectrum + +or will not stay in the +low-energy spectrum. + +The mass will not change. + +And you will see that +when you take that limit, + +you find this +D3-brane remains here. + +And this string, which now will +connect some r to r equal to 0, + +which is now just some AdS. + +This is just some interior +or AdS, infinite proper + +distance away. + +And then you can +check that, in the AdS + +metric, the image of this brane, +viewed from the boundary time-- + +you have to this ratio +factor, et cetera-- + +remains exactly equal to this. + +So this is an important +self-consistency check, + +which I will not do here. + +So now, the story +becomes simple. + +Now we generate such a string, +such a fundamental particle + +with such a mass. + +But in order to introduce an +external particle-- in order + +to have an external particle +take a mass to go to infinity, + +so that means we need to +take r goes to infinity. + +So that means we +want to this D3-brane + +to lie on the boundary of AdS. + +So to summarize, now we want to +move this D3-brane-- in order + +for the external +particle, we want + +to take M goes to +infinity, then we want + +to take r goes to infinity. + +So we want this +D3-brane to actually lie + +on the boundary of AdS. + +So let us just +conclude, summarize. + +An external quark +with infinite mass, + +in N equals 4 super +Yang-Mills theory, + +is described by a string +ending on the boundary of AdS. + +So this is r equal to infinity. + +Because now, we have put in +this D3-brane to the boundary, + +and then we'll, of course, +run into a string ending + +on the boundary of AdS. + +A external quark with +[INAUDIBLE] AdS, of course, + +run into a string ending +at boundary of AdS. + +And in particular, the +location of the string + +can be mapped to the +location of the quark. + +So then endpoint of the string +is the location of the quark. + +So now we have found a very +nice picture that introduces + +a fundamental quark, in N equals +4 super Yang-Mills theory, + +because [? what you ?] +[? need to ?] [? do with ?] + +such a string. + +And now, when you +do a Wilson loop, + +then corresponding to transport +this string around some path, + +then endpoint of +the strings runs + +on a path in the field theory. + +I thought we would stop here. \ No newline at end of file diff --git a/oju-1Ogh1ks.txt b/oju-1Ogh1ks.txt new file mode 100644 index 0000000000000000000000000000000000000000..c4dd9937633084872520023c36bdd876ce11a4dd --- /dev/null +++ b/oju-1Ogh1ks.txt @@ -0,0 +1,2692 @@ +The following content is +provided under a Creative + +Commons license. + +Your support will help MIT +OpenCourseWare continue to + +offer high quality educational +resources for free. + +To make a donation or view +additional materials from + +hundreds of MIT courses, visit +MIT OpenCourseWare at + +ocw.mit.edu. + +PROFESSOR: The first 2/3 of the +course were covering sort + +of what you need to know to know +basic microeconomics-- + +consumer theory and +producer theory. + +And basically you can now, if +you understand the material, + +go forth in the world as a +qualified micro economist. + +What we're going to do for the +rest of the semester is apply + +what we've learned and show you +how you can use the tools + +that we've learned from basic +consumer and producer theory + +to understand a broader +range of phenomena. + +Really, you can think +of this as-- + +as I talked in the first +lecture about we make + +simplifying assumptions-- + +this is sort of as we bend those +simplifying assumptions, + +and consider more and more +realistic applications of + +these models. + +And the hint of what the sort of +stuff you can get to see as + +you move on in economics and +move to our other courses + +beyond micro. + +So what we're going to start +with today-- and of course, + +unfortunately, since I'm going +to cover a lot of topics, I'll + +give each way too little time. + +Including today, which +is one lecture on + +international trade. + +You could take several +courses on it. + +We have an excellent undergrad +course, 14.54 on + +international trade. + +And I'm going to sort of try to +shove down your throats in + +one lecture the key things +you need to know about + +international trade. + +But if you find it interesting +I urge you to + +follow up on this. + +So, thinking about this-- + +a good way to think about +international trade is to + +think about an example. + +So let's think about +Valentine's Day. + +Valentine's Day sort +of presents + +an interesting conundrum. + +Because Valentine's Day +happens in the winter. + +And yet, the thing you're +supposed to do is give roses. + +Which don't grow in the +winter in the US. + +At least not very conveniently +in many places. + +So you've got this difficult +issue that basically we're + +supposed to represent this +holiday with something that + +doesn't actually come +that time of year. + +So historically what that meant +it was if you wanted to + +get roses for Valentine's Day +you to buy them from specially + +heated greenhouses. + +Where they set up largely +to supply the roses for + +Valentine's Day. + +There wasn't really a large +purpose for them otherwise. + +However, over the past couple of +decades, what's happened is + +instead-- instead of growing +these in these specially + +heated greenhouses, we've +started flying them in from + +other places, from Colombia. + +Where of course, Colombia's on +the other side of the equator. + +So February is a wonderful +time to + +grow roses in Colombia. + +And as a result we've started +flying them in. + +And the typical rose you will +give on Valentine's Day this + +year will come from Colombia. + +Now the issue is-- is that a +good thing or a bad thing? + +Now on the one hand, +we get cheap roses. + +That's good. + +Especially for poor college +students who want to impress + +their valentine by sending +a dozen roses. + +It's good they're cheap. + +And roses are way cheaper now +than they were when I was-- + +even in dollar terms when I was +in college giving roses. + +Roses are just incredibly +cheap now compared to + +20 or 30 years ago. + +On the other hand, a lot +of rose producers + +have lost their jobs. + +A lot of people whose +livelihoods and source of + +income was growing these roses +are now out of jobs. + +OK, these are typically people +who are not high-skilled + +people who can go find +another job easily. + +These are people who have been +really displaced for something + +which was a specialized skill +which they cannot easily use + +other places. + +And basically this trade-off is +sort of a microcosm of the + +debate we have over +international trade every day. + +A debate that's ongoing. + +Obama just came back +to the G20 summit. + +Where there was huge discussions +of the issues of + +international trade. + +It's an ongoing debate. + +And it's a particularly +important topic right now in + +the US because the US is running +what's called an + +enormous trade deficit. + +The trade deficit is the +difference between how much we + +export, that is how much of +our goods we sell to other + +countries, minus how +much we import. + +Which is how much of +goods from other + +countries that we buy. + +Currently we export about +$160 billion worth + +of goods every month. + +So every month we send out $160 +billion worth of goods + +around the world. + +We import about $200 billion +of goods every month. + +So that means we have a trade +deficit that's running about + +$40 billion. + +Now the question is-- +is that a problem? + +Is it a problem that the US is +systematically buying more + +stuff from the rest +of the world than + +they're buying from us? + +And the answer is it's not +necessarily a problem. + +And really, it might in fact be +a natural outcome because + +of the principle that we'll +focus on today-- + +the principle of comparative +advantage. + +Comparative advantage is saying +if some other place is + +particularly good at producing +roses in February, then we + +shouldn't be that stressed +about the fact that we're + +running a deficit of roses. + +That's something which is OK in +terms of total efficiency. + +So to see that, let's focus +as this rose example in a + +particularly simplified way. + +Imagine there's two +countries-- + +the US and Colombia. + +And there's only two goods +in the world-- + +roses and computers. + +Two countries, two +good models. + +The standard model we work with +with international trade. + +With two country two good models +you can develop almost + +everything you need to know. + +There is no need to make +it more complicated. + +Now, as I mentioned it's really +hard to grow roses in + +February in the US. + +It's a lot easier in Colombia. + +On the other hand, it's much +easier to produce good + +computers in the US than in +Colombia because we have the + +high skilled labor force that +can produce computers. + +So we have a thing where the +US is relatively bad at + +producing roses in February. + +Colombia's relatively bad +at producing computers. + +So the key point is that means +that the opportunity cost-- + +remember the opportunity cost, +this key concept we've come + +back to a couple times. + +The opportunity cost of +producing a rose in terms of + +producing computers is +relatively high in the US. + +That is to produce a rose we +have to use so many resources. + +Those resources can be much more +effectively deployed to + +producing computers. + +Likewise, in Colombia, to +produce a computer would use a + +ton of resources that would be +much more effectively deployed + +to produce roses. + +As a result we see that Colombia +has a comparative + +advantage in roses. + +And the US has a comparative +advantage in computers. + +The point is that if a country +is relatively good at + +something then they have a +comparative advantage. + +And it's all about +relativities. + +Because people are going +to want both. + +But the key thing is who's +relatively good at producing + +one versus the other. + +So to see that let's +go to figure 19-1. + +To see how we diagram this, +let's go to figure 19-1. + +Figure 19-1 shows production +possibility frontiers. + +You learned about these +a while back. + +Let me remind you, a production +possibility + +frontier we talked about in +the context of a firm. + +It shows the trade-off between +the firm's ability to produce + +one good versus another good. + +So for a firm producing +two goods a production + +possibilities frontier is the +combination of the two goods + +they could produce at a +given level of inputs. + +So we talked about it from the +context of firms. We can also + +talk about this in the +context of countries. + +That says, we can draw a US + +production possibility frontier. + +Which is given the resources the +US has, it could produce + +up to 2000 computers +and no roses. + +Or 1,000 dozen roses, boxes of +roses, and no computers. + +And let's assume it's +linear in between. + +So the US production possibility +frontier is given + +the resources we have-- and +this is a very simplified + +example-- but just +bear with me. + +Given the resources we have, we +can produce 2000 computers + +and no roses or 1,000 boxes +of roses and no computers. + +Or any combination in between. + +That's our production +possibility frontier. + +Columbia has a production +possibility frontier + +illustrated in the +second panel. + +They can produce 1,000 computers +and no roses. + +Or 2000 boxes of roses +and no computers. + +That is, Columbia has +a comparative + +advantage in roses. + +Meaning that their production +possibility frontier is a lot + +flatter than ours is. + +We have a comparative advantage +in computers. + +Meaning our production +possibility frontier is a lot + +steeper than is Colombia's. + +Ignore panel C for the moment. + +Now remember what the slope of +the production possibility + +frontier is. + +It's the marginal rate of +technical substitution. + +It's the marginal rate at +which the producer can + +substitute one good +for another. + +So basically, for the US, the +marginal rate of substitution + +of roses for computers is -2. + +That is you have to give +up two computers to + +get one box of roses. + +In Colombia it's -1/2. + +You have to give up +1/2 a computer to + +get a box of roses. + +So since the marginal rate of +substitution is so much higher + +in the US, we say that Colombia +has a comparative + +advantage in producing roses. + +Now let's go further and impose +tastes on consumers in + +each country. + +Let's say that tastes are such +that given these production + +possibility frontiers, consumers +in the US choose + +1,000 computers and 500 +boxes of roses. + +We choose production +over love. + +Colombia chooses love +over production. + +Given their production +possibility frontier, this is + +not inherently about +taste necessarily. + +Because you have very different +slopes here. + +But given their tastes and their +production possibility + +frontier, they choose +500 computers and + +1,000 boxes of roses. + +Now this we call the outcome. + +We call this outcome the +autarchy outcome. + +Autarchy. + +Which is the word-- + +I don't know what the hell it +means, but it basically means + +no trading. + +Autarchy. + +I don't know where +it comes from. + +Must be some Russian +term or something. + +Autarchy. + +Which means no trading. + +So the no trading outcome is +consumers in the US consume + +1,000 computers and 500 +boxes of roses. + +Consumers in Colombia consume +500 computers and + +1,000 boxes of roses. + +Now the key point is that both +the US and Colombia can be + +better off if we introduce +trade. + +And how is that? + +Well if we introduced trade, +then each country can + +specialize in their comparative +advantage. + +Trade allows for +specialization. + +That is the key advantage +of trade. + +Their comparative advantage +naturally yields + +specialization. + +Comparative advantage +naturally yields + +specialization-- it makes +sense for the US to be a + +computer producer and Columbia +to be a rose producer. + +It doesn't make sense the two +countries to produce both. + +But absent international trade +they have to produce both. + +Because consumers want both. + +So if we're shut off from the +world and Columbia's shut off + +from the world, then we end up +as in figures A and B. But + +once we introduce trade, then +we can take advantage of our + +relative expertise. + +And we get a new production +possibility frontier which + +looks like panel C. + +That is, if you want more +than 2000 computers-- + +so if you want 2000 computers +and 2000 roses-- + +then you simply have the US +produce just computers and + +Colombia produce just roses. + +And you can get 2000 of each. + +Now you can get 3,000 computers +and no roses by + +having everybody produce +computers. + +Or 3,000 roses and no computers +by having everybody + +produce roses. + +So you know production +possibility frontier has its + +sort of wedge point that +2000-2000 intersection. + +You can label that point the +point of specialization where + +those two dashed lines +hit the solid line. + +That's the point of +specialization, pure + +specialization. + +That's the point where the US +does just what it's good at. + +And Colombia does just +what it's good at. + +Of course you could have +other combinations too. + +And that's what leads +to this bent + +production possibility frontier. + +But the key point is this joint +production possibility + +frontier is further out than +what any country could have + +produced on its own. + +We've increased the +opportunity set. + +Specialization has led to a +larger opportunity set. + +A larger opportunity set-- we've +expanded the opportunity + +set for the world by allowing +countries to specialize. + +And the result of that you can +see in the next figure. + +In figure 19-2 which shows +gains from trade. + +So what this figure shows-- + +this is the same autarchy +figure from + +panels A and B before. + +I've just added some +more labels. + +So what we see is, in +autarchy, we're at + +point C- sub US. + +With the US producing and +consuming 1,000 computers and + +500 boxes of roses. + +If we move to specialization, +move to international trade, + +what happens is the US moves +to producing 2000 + +computers at Q-US. + +And, likewise, looking at the +second panel, Colombia moves + +to producing 2000 box +of roses at Q-CO. + +And US consumers now increase +their consumption of both + +roses and computers. + +As do Colombian consumers. + +And you end up with total +consumption of 2000 computers + +and 2000 roses. + +So the US consumes 1250 +computers and Colombia + +consumes 750. + +And the flip for roses. + +So we are learning that +Colombians, even at the same + +price, do prefer love +over production. + +But nonetheless, the bottom +line is, both sets of + +consumers are better off. + +Both sets of consumers are +consuming at a higher point + +than was possible +without trade. + +It's magic. + +The magic is that simply by +letting them trade we have + +made both countries +better off. + +And the magic, the key to the +magic, is specialization and + +comparative advantage. + +If the US and Colombia were +identical in terms of their + +production possibility frontiers +then you should be + +able to see that there would +be no gains from trade. + +If they had the same production +possibility + +frontier, if in A and B the +slopes were the same, then the + +joint production possibility +frontier would be identical to + +what's in each country. + +There would be no gains +from trade. + +Gains from trade come from the +fact that these production + +possibility frontiers have +different slopes. + +That there's comparative +advantage in one country and + +not another. + +Which allows specialization. + +So, basically, the key insight +of international trade-- and + +once again I'm doing now in 50 +minutes what you do in 12 + +lectures when you +get it right. + +But the rough insight is that +comparative advantage yields + +specialization, yields +gains from trade. + +That's sort of the chain +of logic to be + +thinking about this. + +Questions about that? + +Yeah? + +AUDIENCE: If we're going to +adjust to international + +situations? + +Or could it be any sort of + +specialization between two companies? + +PROFESSOR: Any specialization +between two companies. + +So just we learned about +this originally in + +the context of companies. + +Same issue. + +In the business world they +have a term for this. + +What do they call it? + +Synergy. + +You all know that word, you've +got to if you're going to + +business school. + +Synergy. + +Synergy means that somehow you +put two companies together and + +they can produce the +same stuff better. + +Synergy is a fancy +name for this. + +Which is the idea is that +there may be gains from + +specialization even +within a company. + +But if you take the old +example, take two shoe + +companies, both producing left +and right shoes inefficiently + +and they could specialize. + +And one could do better +producing left shoes and one + +at right shoes. + +You put them together +and overall you + +can have more shoes. + +That's actually a pretty +stupid example, + +but you get the point. + +That basically the same +principle can occur whenever + +there are gains from trade. + +Whenever there's comparative +advantage of specialization + +you make gains from trade. + +Good question. + +Other questions? + +Now, that raises the interesting +question of-- well + +these comparative advantage +things sound great. + +Where can I get one? + +Where do comparative advantages +come from? + +And there's really two sources +of comparative advantages. + +Comparative advantage in +international trade. + +So where does comparative +advantage come from? + +One is differences in +factor endowment. + +Differences in factor +endowment. + +What that means, is that +for example, Canada + +has a ton of trees. + +Everywhere. + +Canada is endowed +with an enormous + +amount of lumber resources. + +With that factor very well. + +So Canada is an enormous +exporter of + +lumber and paper products. + +Because they happen to have the +main thing you need for + +that which is unbelievable +amounts of trees, everywhere. + +So Canada can specialize in +exporting lumber and paper. + +So now that gives them +a comparative + +advantage in that area. + +Now let me ask you +another question. + +Why does China export most of +the world's clothes now? + +What? + +AUDIENCE: [INAUDIBLE] + +PROFESSOR: Cheap labor. + +It's not that they have +cheaper textiles. + +It's not that the +cloth itself-- + +and I realize that the silkworms +are in China. + +But not like the actual +production of cloth is that + +much cheaper. + +It's that clothes +are primarily a + +labor intensive good. + +And the labor is cheapest +in China. + +So they have a factor +endowment. + +They have an advantage, +comparative advantage, in + +labor intensive goods. + +So China, with international +trade, will produce a + +disproportionate share of +labor intensive goods. + +Because they can specialize +in labor intensive goods. + +And make them cheaper for +the rest of the world. + +So likewise, a sweatshirt that +you would go and buy today-- + +especially if you go and buy +it at a not top end store. + +At an Old Navy or even +at a Costco. + +Is literally in dollar terms +cheaper than what I paid for + +that same sweatshirt when +I was in college + +in the early 1980s. + +Because they're just +produced incredibly + +cheaply in China now. + +We bring them in and +they're just cheap. + +Goods where you can specialize +in that are going to be-- + +when you take advantage +of specialization + +will be a lot cheaper. + +So that's one reason why you +see comparative advantage. + +The second reason is going to +be technological leadership. + +Technological leadership. + +So, for example, Japan has no +natural comparative advantage + +of producing cars. + +There's no reason why Japan +should have a comparative + +advantage of producing +cars over the US. + +Except they developed the +technology to more efficiently + +mass produce the modern +automobile. + +As a result of that +technological leadership they + +gave themselves, essentially, +comparative advantage. + +Now, once that technology +becomes public, the production + +shifts elsewhere. + +So now China is a major +producer of cars. + +Basically copy-catting the +technology developed in Japan. + +So it does move elsewhere. + +Unlike factor endowments-- + +if the US wanted to compete with +Canada I guess we could + +plant trees and in 50 years +we would compete. + +But factor endowments are kind +of hard to compete on. + +Technology is potentially a +little bit easier because you + +can reverse engineer things. + +So once again, the + +technology's shifting to China. + +So really the answer is in the +long run everything's going to + +be made in China. + +Because they've got +the cheap labor. + +And they're adopting +the technology. + +And once again, to quote towards +our most important + +sense of cultural relevance, +there's the episode of the + +Simpsons where Homer says, +don't worry we're fine. + +We're going to rule-- + +our country's going +to rule the world. + +We're fine in the future. + +He goes, wait a second +we're China, right? + +So basically China is doing very +well because they've got + +these factor endowments-- + +these great factor endowments +and because they are adopting + +technology as well. + +What's interesting about this +is this really leads to some + +more interesting +policy issues. + +Once again, factor endowment +you can't + +do a whole lot about. + +The interesting policy issues +are in technological progress. + +This is an argument that many +people make for subsidizing + +new technologies. + +So you often hear President +Obama saying, we need to + +subsidize green technologies. + +This is the wave +of the future. + +The idea, what he's saying +implicitly is if we get the + +technological leadership, we +can make the green products + +that are exported. + +Not the color-- + +I mean environmental stuff-- +that can be exported to the + +rest of the world. + +And that's the argument +that he's making. + +Question about that? + +Now let's talk about where we +started the lecture, which is + +is trade a good thing +or a bad thing? + +I just talked about how trade +can greatly increase + +consumption possibilities. + +But why haven't we talked +about the consumers? + +What about overall +social welfare. + +And the answer is that +trade unambiguously + +increases social welfare. + +That trade is unambiguously +a good thing to do. + +So to see that let's go to the +next series of figures. + +Start with figure 19-3. + +So let's start with the +market for roses + +and imagine we have-- + +[INAUDIBLE] autarchy is +sometimes spelled with a K, + +sometimes with a CH, I don't +know what the right way to + +spell it is. + +But anyway, you have autarchy. + +So the US-- imagine the old days +where we produced all our + +roses and we're at some +equilibrium with some consumer + +surplus and producer surplus. + +So we produce Q sub A roses +at a price p sub A. + +Now, in figure 19-4 we're +going to introduce + +international trade. + +It's a little confusing, so +let's go through it slowly. + +Figure 19-4. + +You can find on that figure the +domestic supply and the + +domestic demand. + +And they intersect at point A. +Figure 19-4, domestic supply + +and domestic demand intersect +at A. Which is once again a + +quantiy of Q sub A and +a price of P sub a. + +Now let's say that what happens +is we now allow + +imports of roses. + +We now trade with Colombia +for roses. + +What that does is that means now +instead of just drawing on + +the domestic supply, we +can now draw on the + +world's supply of roses. + +We don't have to just rely +on domestic supply. + +Well, that by definition has +shifted further out. + +And it's shifted further out +because other countries + +countries can produce roses so +much more cheaply than we can. + +So we can rely on the world's +supply of roses. + +Remember my cotton example where +you first buy from the + +cheapest country, then the next + +cheapest country, et cetera. + +This is what we're saying-- +if the US was the cheapest + +producer of roses, this +wouldn't shift out. + +But since the US is not the +cheapest producer of roses + +this shifts out to +world supply. + +And we get to a new +equilibrium at + +quantity C sub t. + +That's the new quantity +of roses we consume. + +And a lower price P sub w. + +The horizontal line's a little +distracting, actually. + +But basically what you have +here-- the horizontal line is + +just showing the price in +autarchy and the world price. + +But the bottom line is, what +you get you get is you get + +this new equilibrium with +a quantity C sub t and + +a price P sub w. + +And in particular, what we're +seeing is that total domestic + +consumption of roses +has increased. + +But domestic production +has fallen. + +Because look, the new price +intersects the supply + +curve at Q sub t. + +So what happens is at that new +lower price P sub w, US rose + +producers aren't actually +producing as much. + +So US domestic production falls +from Q sub a to Q sub t. + +But US consumption rises from +Q sub a to C sub t. + +The difference is imports. + +Production falls from +Q sub a to Q sub t. + +Consumption rises from +Q sub a to C sub t. + +The difference is imports. + +And that's what happens +when we allow + +Colombia to send us roses. + +What are the welfare +implications of that? + +Let's go to figure 19-5. + +And what you can see is we +can show you the welfare + +implications. + +Previously consumer surplus was +W. Producer surplus was X + +plus that other white triangle +below X. Now what's happened? + +Consumer surplus has gone up by +X, because consumers have + +gained that plus z. + +So consumers have gained that +entire trapezoid, X plus Z. + +Producers have lost x. + +Producers have lost that +trapezoid, X. So in total + +we've gained Z. We've gained +that entire triangle, Z. Z is + +the entire triangle on both +sides of the dashed line. + +So we've gained all of Z. +Consumers gained X plus Z, + +producers lost X. We've gained +Z. So overall we've increased + +welfare in the US. + +So basically consumers +win, producers lose. + +And that's the problem. + +The political problem we have. +And I'll come back to this. + +What you can see is consumers +win, producers lose. + +But by definition, consumers win +more than producers lose. + +So overall, social surplus +has gone up. + +Now that's the case +of imports. + +Now what about exports? + +Well if imports make +us better, do + +exports make us worse? + +We just said imports +make us better. + +What about exports? + +Well let's look at that +in figure 19-6. + +Now figure 19-6 shows what +happens with exports. + +Once again we start at point A, +the domestic outcome, point + +A. And now we're talking +about computers. + +So now the US is going +to export computers. + +What that means is that the +supply of computers to people + +in the US is going to fall. + +why? + +Because a bunch of them are +going to get sent away. + +So it used to be US consumers +got to consume on that + +domestic supply-- + +so US producers used domestic +supply curve. + +And we had domestic demand +intersecting at A. Well now, + +domestic producers are shipping +a bunch of the + +computers to Japan, and +China, and Colombia. + +As a result, the supply +has shifted in. + +Because they don't have +as many computers + +to sell in the US. + +That means the price rises. + +So because of exports we pay +more for our computers. + +And it sort of makes +sense, right? + +They produce a bunch +of computers. + +If there's been a great demand +for them elsewhere and we want + +them too, we're going to have +to pay a higher price. + +Because we're competing +with other + +people for those computers. + +So now that supply curve +has shifted up. + +And now we end up that US +consumers only want to C sub t + +computers at a new higher +price a P sub w. + +But the world is now saying, +well we are interested in the + +total amount of computer +we want is Q sub t. + +So what that world +price of sub w-- + +the domestic producers say +great, at that higher price P + +sub w, I'm delighted to produce +Q sub t computers. + +So what I'm going to do is I'm +going to produce Q sub t, I'm + +going to ship Q sub t minus +C sub t elsewhere. + +And US consumers will +consume C sub t. + +So consumers are worse off. + +So unlike imports which make +consumers better off, + +consumers are worse off. + +So is trade bad? + +Well, no. + +Trade's not bad. + +But the bottom line is, domestic +producers are going + +to gain more than domestic +consumers lose. + +The bottom line is we'll be +better off from exports. + +But in this case, consumers +lose and producers win. + +Society gains either way. + +Society gains from imports +because consumers gain more + +than producers lose. + +Society gains from exports. + +Because producers gain more +than consumers lose. + +So what that means is that any +form of trade is going to make + +the US better off. + +But also inevitably +create losers. + +Any form of trade will make +the US better off but + +inevitably create losers. + +And the problem is that those +losers are very loud in the + +political process. + +And the winners are +not so loud. + +So, for example, if you polled +US consumers and said, how + +much are you saving on +your sweat shirts? + +Because we import textiles +from China. + +They wouldn't know. + +I mean they'd say a +couple bucks what + +in fact it's maybe-- + +they'd say I don't know, 10% of +the price when it's maybe + +more like 50% of the price. + +But if you polled US textile +manufacturers, or guys who + +have left the business, and +said how much did you lose + +because of imports of China, +they'd tell you exactly how + +much they lost. They'd tell +you 10 times as much. + +But they know how much they +lost. And they go to their + +politicians and they say, hey +we're losing jobs here. + +And the consumers don't come +saying, hey I'm getting + +cheaper sweatshirts here. + +As a result, there's huge +political backlash against + +imports in particular. + +So that leads to policies +which limit imports into + +countries like the US. + +Like tariffs, which are +essentially taxes. + +Tariffs, which are essentially +taxes on goods imported into + +the US to us. + +Which are taxes on goods that +are imported into the US. + +Or quotas, which are limits +on how much companies + +can send to the US. + +What I think what you should +know now is by definition-- + +since I said free trade +is good, these things + +are going to be bad. + +And they're going to be bad-- + +things like tariffs are going +to be bad because they're + +going to hurt US consumers more +than they're going to + +help US producers. + +So to see that let's +go to figure 19-8. + +Let's show what happens +with a tariff. + +This is saying that now we're +starting the world with trade. + +So the world with trade we're +producing C sub 1, which is + +where domestic demand equals +world supply at + +a price P sub w. + +That's where we were +with trade. + +Now the US government comes +in and levies a tariff. + +And says that that tariff is +going to be the difference + +between P sub w and P sub t. + +So that's the amount +of the tariff. + +They are going to raise the +price essentially to P sub t. + +They're essentially going to +levy a tax on roses that come + +in from Colombia. + +What that does is that means +that consumers now, at that + +higher price, only want +C sub 2 roses. + +That's where that intersects +demand. + +So they wanted C sub 1 roses +without the tariff. + +But now with the tariff at that +higher price intersects + +demand at C sub 2, they only +want C sub 2 roses. + +Producers, given that they have +to pay the tariff, are + +only going to produce Q sub 2. + +Domestic producers are now going +to produce Q sub 2 roses + +because they get +a higher price. + +So domestic consumers +are consuming less. + +Domestic producers are +producing more. + +Right, because now that +price is higher. + +So now you could reopen those +heated greenhouses because + +it's worth it now. + +And we end up with a much +smaller amount of imports. + +So in that sense the +tariff worked. + +So in the sense that the goal +of the tariff was to reduce + +imports, it worked. + +Consumers wanted less +from Colombia. + +Producers were happy +to produce more. + +So imports fell. + +So in that sense +tariffs worked. + +They've lowered imports. + +But what do they +do to welfare? + +Well that's our final +figure 19-9. + +What do they do to welfare? + +Well what you can see is +domestic producers gained a + +trapezoid A. Their producer +surplus, which used to be that + +little white triangle below A, +became that entire triangle + +that includes A and the +white part below it. + +So their producer surplus became +A. They gained A in + +producer surplus. + +But consumers lost a ton. + +They lost the entire trapezoid +A plus B plus C plus D. They + +lost that entire trapezoid +gone up to higher prices. + +And now we have one other +player which is the + +government. + +The government made +some money. + +This is a tax. + +How much did the government +make? + +Well we taxed all imports +by the amount P sub + +t minus P sub w. + +So the government made the +rectangle C. The government + +made C because we got +to tax all the + +important at that tariff. + +So on net, society as a whole +is worse off by B plus D. + +Consumers have lost the entire +A plus B plus C plus D. + +Producers got some of that, the + +government got some of that. + +But some of it's dead +weight loss. + +Trades that would have made +consumers better off, and + +worldwide producers better off +that are not happening. + +So this tariff, it +had its effect. + +It lowered imports. + +But at the same time it lowered +social surplus. + +So restrictions on trade +lower welfare. + +And this is why economists +like free trade. + +Because restrictions on +trade lower welfare. + +Are there questions +about that? + +Moreover, this is just what +we call static analysis. + +What else could happen if the +US government voted a tariff + +on roses coming from Colombia? + +What else might happen? + +Yeah? + +AUDIENCE: Colombia might vote +for a tariff on the U.S. + +PROFESSOR: Columbia might vote +for a tariff against computers + +coming from the US. + +Which of course would hurt +Colombian consumers. + +But would also hurt +US producers. + +So from the US's prospective, +that would be even worse. + +So think about it-- + +we put a tariff on Colombian +roses which hurt us. + +Then Colombia puts a tariffs on +US computers which hurts us + +even further-- hurts Colombia +too, but we don't care about + +them, we care about us. + +It hurts us even further. + +So dynamically restrictions on +trade can be even worse than + +it looks in this diagram. + +If they cause a trade war you +can actually end up with + +things being even worse than +you look at this diagram. + +So we talked about why +economists like free trade-- + +partly so that the gains +to consumers exceed + +the losses to producers. + +But partly it's because free +trade begets free trade. + +And that exports make +us better off too. + +So by allowing free trade not +only do we increase our + +welfare by having more imports, +we also increased our + +welfare by allowing +more exports. + +And in fact, producers as a +class, if they could all get + +together and have a cooperative +equilibrium, they + +might be fine without +restrictions of trade. + +Because the computer producers +and the rose producers get + +together and say, wait a second, +we can trade, on net + +we win from this. + +On net we win from free trade. + +Let's get together +and make a deal. + +But of course we know that's +going to be an incredibly hard + +cooperative equilibrium +to enforce. + +And that's why you have +different sets of producers. + +You have the rose producers +lobbying the congressmen. + +Then they leave and the computer +producers walk in his + +office and lobby him +the other way. + +So you have producers lobbying +for different effects + +depending if they're +competing with + +imports or they're exporting. + +They're going to lobby for and +against trade restrictions. + +Moreover, there's yet another +thing we've missed. + +There's yet another thing +we've missed. + +So we've talked about the +dead weight loss. + +We've talked about trade wars. + +But let's say for a second-- +let's think + +about a third thing. + +Let's say for a second +we're not just + +heartless selfish Americans. + +But we actually do care about +the rest of the world. + +Well the third thing we miss +is allowing trade from + +Colombia makes Colombia +better off too. + +So not only have we improved +our welfare by importing + +Colombian roses, we've improved +their welfare too. + +And they're a poor country. + +And we should be happy to +improve their welfare too. + +We think about free +trade in Vietnam. + +That is the application +for child labor. + +By allowing the import of +Vietnamese rice we improved + +the lives of the Vietnamese +children. + +So independent of the fact we've +made our lives better + +off we've made these +other country's + +lives better off too. + +So there's three reasons why +we should have free trade. + +There's the simple welfare +gain, there's the dynamic + +welfare gain, and there's the +fact that we might care about + +the welfare of other +countries as well. + +And as a result, there's been +a huge emphasis over time in + +trying to increase free trade. + +By economists saying this for +years, things going back to + +the early economists. + +But we've made a lot of headway +in the last 20 years. + +And in particular, one big +source of headway was NAFTA-- + +The North American Free +Trade Agreement. + +Which was passed +under Clinton. + +Which basically demolished trade +barriers between Canada + +the US and Mexico. + +There used to be a lot +of trade barriers. + +We would tax Canadian lumber. + +They would tax our computers. + +We would tax Mexican whatever +they sent to us. + +They would tax our stuff. + +It was a mess. + +So basically NAFTA said let's +just get rid of all of it. + +Let's have a cooperative +agreement. + +Let's have a cooperative +agreement whereby we all agree + +to get rid of trade barriers and +thereby making all of us + +better off. + +And it seems like it would be +a pretty simple thing to do. + +But it was a mess. + +And it was very hard. + +And it was very hard because now +you had parties in every + +country opposing this. + +You had you had the +Canadian computer + +producers getting upset. + +You had the Mexican computer +producers getting upset. + +You had the US lumber industry +getting upset. + +And you had huge difficulties +because you had parties in + +every case opposing it. + +And the reason free trade +agreements are so difficult-- + +now eventually NAFTA did pass. + +And has been by most measures +a huge success. + +But ultimately the major +difficulty here is in another + +failure of government policy. + +Which is the inability of the +government to effectively tax + +the winners and compensate +the losers from + +international trade. + +That is-- + +if the government could +work as a perfect-- + +in the way that I design +it to work-- + +what would happen is that we +would tax sweatshirts and take + +the money from taxing +sweatshirts and send it to + +compensate the guys who lost +jobs in the textile industry. + +And if we did that, we can make +life much better off than + +with the tariff. + +So if consider two outcomes. + +One is we don't import +Chinese sweatshirts. + +The other is that we import them +but we levy a small tax + +on all sweatshirts not just +Chinese lectures. + +Levy a small tax on +all sweatshirts. + +We import Chinese sweatshirts +but then we levy a tax on all + +sweatshirts. + +And we use that sweatshirt tax +money to pay off the guys who + +lost their jobs in the +textile industry. + +That would be better for society +than would not allow + +sweatshirts to come in +in the first place. + +So the fundamental failure in +trade policy ultimately is a + +failure is that inability of the +government to effectively + +compensate the losers by +taxing the winners. + +Because just as the losers know +to go to lobby Congress, + +the winners will get pissed +off if you start taxing + +sweatshirts. + +Because they don't realize that +they're saving all this + +money from all these imports. + +And in fact the typical American +voter would probably + +vote to block Chinese imports +before they'd vote to have a + +tax on their sweatshirts. + +So really in some sense when you +have a very concentrated + +set of winners or losers +competing against a very + +concentrated set of losers, +defeating against a very + +diffuse set of winners, that's a +hard policy to get in place. + +Unless you can figure out a way +to get those winners to + +compensate the losers. + +And that's the tricky thing. + +Are there question about that? + +About free trade agreements, +things like that? + +Now what I want to talk about +for a couple minutes then one + +subtlety in these free +trade agreements. + +And why things like +NAFTA are hard. + +And the reason they're +hard is because this + +makes enormous sense. + +Free trade agreements make +enormous sense if it's true + +comparative advantage like +Canada has more trees. + +But what if Mexico's source of +comparative advantage is that + +they treat their workers +like shit. + +What if China's source of +comparative advantage is that + +they have incredibly bad +working conditions? + +And they have incredibly bad +environmental conditions? + +China has an incredibly bad +environmental situation. + +It is incredibly dangerous +just to live in + +major Chinese cities. + +The working conditions +are awful. + +The wages are terrible. + +Nonetheless, the result is +very, very cheap labor. + +Then things get a +little dicier. + +Because if the Chinese labor was +cheap or Mexican labor was + +cheap just because inherently +that was just + +the way life was. + +At the same working conditions +and the same environmental + +conditions they were just +cheaper, then that's great. + +That's the comparative +advantage. + +But if they're cheap because +they exploit their population + +and put them in horrible working +conditions and facing + +horrible environmental +conditions, then the welfare + +gets a little trickier. + +From the US's prospective it +doesn't get any trickier. + +The US-- + +our welfare is exactly +the same. + +We get these static and dynamic +gains from trade. + +But from a world perspective, +now we're maybe not so sure we + +want to promote Mexico producing +more clothes or + +China producing more clothes. + +Because it could just lead to +more exploitation of the + +population. + +So this comes back to when I +talked about free trade in + +Vietnam and child labor. + +Which is if free trade actually +let to an increased + +use of child labor in Vietnam we +might worry that gee maybe + +this isn't such a good thing. + +So really what it comes down +to is we have to think not + +just about the simple +dead weight loss + +triangles and squares. + +We have to think about some +broader social issues as well. + +And once again there is +a right answer here. + +And this is what a lot was +fought over with NAFTA. + +Which is one of the conditions +for NAFTA was the US actually + +lobbied and got significantly +improved work and + +environmental standards +in Mexico. + +This was like an opposite +of a trade war. + +Instead of being a vicious +cycle, this + +was a virtuous cycle. + +We actually improved the life +for workers in Mexico because + +Mexico is willing to do that in +order to get the benefits + +of trade with the US. + +So just like limiting trade with +Mexico will hurt us and + +hurt Mexico, expanding trade +with Mexico and then tying it + +to improve work conditions and +environmental conditions can + +make both countries really +much better off. + +And so that's where, once again, +trade becomes very + +interesting. + +And why it's worth +studying further. + +Because it's not as simple +as these boxes. + +It's thinking about +where comparative + +advantage comes from. + +And whether we really want to +promote trade with countries + +that have comparative advantage +depending on the + +source of what that comparative +advantage is. + +And that's sort of +the free trade + +versus fair trade argument. + +The bottom line in +that argument-- + +the free trade versus fair trade +argument-- the bottom + +line is free trade is +always a good thing. + +But fair trade considerations +can be used to try to make it + +work better than just simply +unfettered free trade. + +And so really both sides have +a point in this debate. + +So let me stop there. + +That's international trade. + +We're going to come back on +Wednesday to talk about + +uncertainty and whether you +should play the lottery. \ No newline at end of file diff --git a/pCoDwHg5Vh8.txt b/pCoDwHg5Vh8.txt new file mode 100644 index 0000000000000000000000000000000000000000..d65ff5bd580c2b37707be3d6d3c982f84acffd1f --- /dev/null +++ b/pCoDwHg5Vh8.txt @@ -0,0 +1,2259 @@ +align:start position:0% + +welcome back to 8701 + + align:start position:0% +welcome back to 8701 + + + align:start position:0% +welcome back to 8701 +in this lecture we talk about cp + + align:start position:0% +in this lecture we talk about cp + + + align:start position:0% +in this lecture we talk about cp +symmetry or cp violation + + align:start position:0% +symmetry or cp violation + + + align:start position:0% +symmetry or cp violation +in previous lectures we discussed that + + align:start position:0% +in previous lectures we discussed that + + + align:start position:0% +in previous lectures we discussed that +the weak interaction is not invariant + + align:start position:0% +the weak interaction is not invariant + + + align:start position:0% +the weak interaction is not invariant +under parity and charge conjugation + + align:start position:0% +under parity and charge conjugation + + + align:start position:0% +under parity and charge conjugation +transformation + + align:start position:0% +transformation + + + align:start position:0% +transformation +but now we can ask the question how + + align:start position:0% +but now we can ask the question how + + + align:start position:0% +but now we can ask the question how +about cp + + align:start position:0% +about cp + + + align:start position:0% +about cp +so a transformation which does charge + + align:start position:0% +so a transformation which does charge + + + align:start position:0% +so a transformation which does charge +conjugation and + + align:start position:0% +conjugation and + + + align:start position:0% +conjugation and +parity transformation so the classical + + align:start position:0% +parity transformation so the classical + + + align:start position:0% +parity transformation so the classical +example to show parity violation is + + align:start position:0% +example to show parity violation is + + + align:start position:0% +example to show parity violation is +the decay of a pion so we have here + + align:start position:0% +the decay of a pion so we have here + + + align:start position:0% +the decay of a pion so we have here +this um charged pioneers in zero + + align:start position:0% +this um charged pioneers in zero + + + align:start position:0% +this um charged pioneers in zero +and it decays into a neuron and a + + align:start position:0% +and it decays into a neuron and a + + + align:start position:0% +and it decays into a neuron and a +neutrino an anti-muon and a neutrino + + align:start position:0% +neutrino an anti-muon and a neutrino + + + align:start position:0% +neutrino an anti-muon and a neutrino +and so since the neutrino is left-handed + + align:start position:0% +and so since the neutrino is left-handed + + + align:start position:0% +and so since the neutrino is left-handed +the out of the decay coming + + align:start position:0% +the out of the decay coming + + + align:start position:0% +the out of the decay coming +anti-muron needs to be left-handed as + + align:start position:0% +anti-muron needs to be left-handed as + + + align:start position:0% +anti-muron needs to be left-handed as +well + + align:start position:0% +well + + + align:start position:0% +well +so if you do parity transformation of + + align:start position:0% +so if you do parity transformation of + + + align:start position:0% +so if you do parity transformation of +this decay you see that the outcoming + + align:start position:0% +this decay you see that the outcoming + + + align:start position:0% +this decay you see that the outcoming +muon would be right-handed on the other + + align:start position:0% +muon would be right-handed on the other + + + align:start position:0% +muon would be right-handed on the other +hand + + align:start position:0% +hand + + + align:start position:0% +hand +there is no right-handed adrenal and + + align:start position:0% +there is no right-handed adrenal and + + + align:start position:0% +there is no right-handed adrenal and +therefore this decay is not possible + + align:start position:0% +therefore this decay is not possible + + + align:start position:0% +therefore this decay is not possible +so this is not so this mirror symmetry + + align:start position:0% +so this is not so this mirror symmetry + + + align:start position:0% +so this is not so this mirror symmetry +is not realized in nature + + align:start position:0% +is not realized in nature + + + align:start position:0% +is not realized in nature +it's a consequence of the weak + + align:start position:0% +it's a consequence of the weak + + + align:start position:0% +it's a consequence of the weak +interaction so similarly we could do a + + align:start position:0% +interaction so similarly we could do a + + + align:start position:0% +interaction so similarly we could do a +charge transformation + + align:start position:0% +charge transformation + + + align:start position:0% +charge transformation +charge conjugation of this decay so you + + align:start position:0% +charge conjugation of this decay so you + + + align:start position:0% +charge conjugation of this decay so you +turn + + align:start position:0% +turn + + + align:start position:0% +turn +particles into the anti-particles and + + align:start position:0% +particles into the anti-particles and + + + align:start position:0% +particles into the anti-particles and +you find here + + align:start position:0% +you find here + + + align:start position:0% +you find here +this anti-neutrino which is left-handed + + align:start position:0% +this anti-neutrino which is left-handed + + + align:start position:0% +this anti-neutrino which is left-handed +and also those don't exist in nature + + align:start position:0% +and also those don't exist in nature + + + align:start position:0% +and also those don't exist in nature +so parity or charged conjugation doesn't + + align:start position:0% +so parity or charged conjugation doesn't + + + align:start position:0% +so parity or charged conjugation doesn't +really work on those decays those weak + + align:start position:0% +really work on those decays those weak + + + align:start position:0% +really work on those decays those weak +decays but what does work if you apply + + align:start position:0% +decays but what does work if you apply + + + align:start position:0% +decays but what does work if you apply +the parity and charge conjugation + + align:start position:0% +the parity and charge conjugation + + + align:start position:0% +the parity and charge conjugation +together + + align:start position:0% +together + + + align:start position:0% +together +you turn the positively charged + + align:start position:0% +you turn the positively charged + + + align:start position:0% +you turn the positively charged +pion into a negatively charged spine + + align:start position:0% +pion into a negatively charged spine + + + align:start position:0% +pion into a negatively charged spine +the antimural intermediary and the + + align:start position:0% +the antimural intermediary and the + + + align:start position:0% +the antimural intermediary and the +neutrino and an antineutrino + + align:start position:0% +neutrino and an antineutrino + + + align:start position:0% +neutrino and an antineutrino +and you see here that the antineutrino + + align:start position:0% +and you see here that the antineutrino + + + align:start position:0% +and you see here that the antineutrino +is right handed + + align:start position:0% +is right handed + + + align:start position:0% +is right handed +um so is the the muon and so that decay + + align:start position:0% +um so is the the muon and so that decay + + + align:start position:0% +um so is the the muon and so that decay +is actually observed in nature + + align:start position:0% +is actually observed in nature + + + align:start position:0% +is actually observed in nature +good so we saved the day you know it + + align:start position:0% +good so we saved the day you know it + + + align:start position:0% +good so we saved the day you know it +seems like + + align:start position:0% +seems like + + + align:start position:0% +seems like +that cp that the weak interaction is + + align:start position:0% +that cp that the weak interaction is + + + align:start position:0% +that cp that the weak interaction is +invariant + + align:start position:0% +invariant + + + align:start position:0% +invariant +under cp transformation however + + align:start position:0% +under cp transformation however + + + align:start position:0% +under cp transformation however +that's not quite true um + + align:start position:0% +that's not quite true um + + + align:start position:0% +that's not quite true um +german and pace noted that in + + align:start position:0% +german and pace noted that in + + + align:start position:0% +german and pace noted that in +systems of neutral chaons there's an odd + + align:start position:0% +systems of neutral chaons there's an odd + + + align:start position:0% +systems of neutral chaons there's an odd +effect + + align:start position:0% +effect + + + align:start position:0% +effect +and the fact is that a particle a k knot + + align:start position:0% +and the fact is that a particle a k knot + + + align:start position:0% +and the fact is that a particle a k knot +can turn into an anti-particle + + align:start position:0% +can turn into an anti-particle + + + align:start position:0% +can turn into an anti-particle +by changing the strangeness + + align:start position:0% +by changing the strangeness + + + align:start position:0% +by changing the strangeness +and that's possible in these kind of + + align:start position:0% +and that's possible in these kind of + + + align:start position:0% +and that's possible in these kind of +box diagrams which include you know a + + align:start position:0% +box diagrams which include you know a + + + align:start position:0% +box diagrams which include you know a +box + + align:start position:0% +box + + + align:start position:0% +box +with a couple of w's um + + align:start position:0% +with a couple of w's um + + + align:start position:0% +with a couple of w's um +and it's easy to see that you know if + + align:start position:0% +and it's easy to see that you know if + + + align:start position:0% +and it's easy to see that you know if +you could prepare + + align:start position:0% +you could prepare + + + align:start position:0% +you could prepare +prepare uh you know decay on it will + + align:start position:0% +prepare uh you know decay on it will + + + align:start position:0% +prepare uh you know decay on it will +oscillate because those diagrams are + + align:start position:0% +oscillate because those diagrams are + + + align:start position:0% +oscillate because those diagrams are +possible + + align:start position:0% +possible + + + align:start position:0% +possible +into an anti-particle so now what is + + align:start position:0% +into an anti-particle so now what is + + + align:start position:0% +into an anti-particle so now what is +happening now to cp here + + align:start position:0% +happening now to cp here + + + align:start position:0% +happening now to cp here +if i apply cp on a k on i find a minus + + align:start position:0% +if i apply cp on a k on i find a minus + + + align:start position:0% +if i apply cp on a k on i find a minus +sign in an antique + + align:start position:0% +sign in an antique + + + align:start position:0% +sign in an antique +so if you want to analyze this further + + align:start position:0% +so if you want to analyze this further + + + align:start position:0% +so if you want to analyze this further +you might want to find the eigenstates + + align:start position:0% +you might want to find the eigenstates + + + align:start position:0% +you might want to find the eigenstates +to this and so the eigenstates can be + + align:start position:0% +to this and so the eigenstates can be + + + align:start position:0% +to this and so the eigenstates can be +found as k1 and k2 which are up mixtures + + align:start position:0% +found as k1 and k2 which are up mixtures + + + align:start position:0% +found as k1 and k2 which are up mixtures +of the k naught and the on decay knot + + align:start position:0% +of the k naught and the on decay knot + + + align:start position:0% +of the k naught and the on decay knot +you find this symmetric the symmetric + + align:start position:0% +you find this symmetric the symmetric + + + align:start position:0% +you find this symmetric the symmetric +and the antisymmetric + + align:start position:0% +and the antisymmetric + + + align:start position:0% +and the antisymmetric +states good so if you apply cp on the + + align:start position:0% +states good so if you apply cp on the + + + align:start position:0% +states good so if you apply cp on the +eigen + + align:start position:0% +eigen + + + align:start position:0% +eigen +states you find eigenvalues of one and + + align:start position:0% +states you find eigenvalues of one and + + + align:start position:0% +states you find eigenvalues of one and +minus one + + align:start position:0% +minus one + + + align:start position:0% +minus one +it turns out that the lifetime of the k1 + + align:start position:0% +it turns out that the lifetime of the k1 + + + align:start position:0% +it turns out that the lifetime of the k1 +and the k2 those eigenstates + + align:start position:0% +and the k2 those eigenstates + + + align:start position:0% +and the k2 those eigenstates +is very different you know one is 10 to + + align:start position:0% +is very different you know one is 10 to + + + align:start position:0% +is very different you know one is 10 to +the minus 10 and one is 5 times 10 to + + align:start position:0% +the minus 10 and one is 5 times 10 to + + + align:start position:0% +the minus 10 and one is 5 times 10 to +the minus 8. + + align:start position:0% +the minus 8. + + + align:start position:0% +the minus 8. +so the k1 decays much much quicker than + + align:start position:0% +so the k1 decays much much quicker than + + + align:start position:0% +so the k1 decays much much quicker than +the k2 + + align:start position:0% +the k2 + + + align:start position:0% +the k2 +so this then sets the stage to a test of + + align:start position:0% +so this then sets the stage to a test of + + + align:start position:0% +so this then sets the stage to a test of +cp + + align:start position:0% +cp + + + align:start position:0% +cp +violation so what you're going to do is + + align:start position:0% +violation so what you're going to do is + + + align:start position:0% +violation so what you're going to do is +prepare a beam of + + align:start position:0% +prepare a beam of + + + align:start position:0% +prepare a beam of +decay 0s and that's mdk + + align:start position:0% +decay 0s and that's mdk + + + align:start position:0% +decay 0s and that's mdk +um and only after some time you study + + align:start position:0% +um and only after some time you study + + + align:start position:0% +um and only after some time you study +the beam again + + align:start position:0% +the beam again + + + align:start position:0% +the beam again +which then should be made up solely of + + align:start position:0% +which then should be made up solely of + + + align:start position:0% +which then should be made up solely of +k2 + + align:start position:0% +k2 + + + align:start position:0% +k2 +so if you in that beam observe the case + + align:start position:0% +so if you in that beam observe the case + + + align:start position:0% +so if you in that beam observe the case +of the k2 into two pions + + align:start position:0% +of the k2 into two pions + + + align:start position:0% +of the k2 into two pions +you noted that there is an add mixture + + align:start position:0% +you noted that there is an add mixture + + + align:start position:0% +you noted that there is an add mixture +again + + align:start position:0% +again + + + align:start position:0% +again +um which violates cp + + align:start position:0% +um which violates cp + + + align:start position:0% +um which violates cp +so you have an admixture of k1's in in + + align:start position:0% +so you have an admixture of k1's in in + + + align:start position:0% +so you have an admixture of k1's in in +in a beam which should just be of k2s + + align:start position:0% +in a beam which should just be of k2s + + + align:start position:0% +in a beam which should just be of k2s +so that mixture then will violate + + align:start position:0% +so that mixture then will violate + + + align:start position:0% +so that mixture then will violate +cp invariants and exactly that was done + + align:start position:0% +cp invariants and exactly that was done + + + align:start position:0% +cp invariants and exactly that was done +so cronin and fitch picked up this idea + + align:start position:0% +so cronin and fitch picked up this idea + + + align:start position:0% +so cronin and fitch picked up this idea +they have set up an experiment + + align:start position:0% +they have set up an experiment + + + align:start position:0% +they have set up an experiment +in which they produced chaons they had + + align:start position:0% +in which they produced chaons they had + + + align:start position:0% +in which they produced chaons they had +them decay + + align:start position:0% +them decay + + + align:start position:0% +them decay +and then they studied later in the beam + + align:start position:0% +and then they studied later in the beam + + + align:start position:0% +and then they studied later in the beam +whether or not + + align:start position:0% +whether or not + + + align:start position:0% +whether or not +they could find to priority case and + + align:start position:0% +they could find to priority case and + + + align:start position:0% +they could find to priority case and +they did + + align:start position:0% +they did + + + align:start position:0% +they did +indeed observe 42 or 45 + + align:start position:0% +indeed observe 42 or 45 + + + align:start position:0% +indeed observe 42 or 45 +by mdks two pion decays in a total of 22 + + align:start position:0% +by mdks two pion decays in a total of 22 + + + align:start position:0% +by mdks two pion decays in a total of 22 +700 decays so that means that this k + + align:start position:0% +700 decays so that means that this k + + + align:start position:0% +700 decays so that means that this k +long beam the long lift k on beam + + align:start position:0% +long beam the long lift k on beam + + + align:start position:0% +long beam the long lift k on beam +is actually an arc mixture of k2 + + align:start position:0% +is actually an arc mixture of k2 + + + align:start position:0% +is actually an arc mixture of k2 +with a small additional component of k1 + + align:start position:0% +with a small additional component of k1 + + + align:start position:0% +with a small additional component of k1 +so here they observed um + + align:start position:0% +so here they observed um + + + align:start position:0% +so here they observed um +cp violation through the mixture of + + align:start position:0% +cp violation through the mixture of + + + align:start position:0% +cp violation through the mixture of +those states and this epsilon gives you + + align:start position:0% +those states and this epsilon gives you + + + align:start position:0% +those states and this epsilon gives you +a + + align:start position:0% +a + + + align:start position:0% +a +you know size of the strength of the cp + + align:start position:0% +you know size of the strength of the cp + + + align:start position:0% +you know size of the strength of the cp +violation + + align:start position:0% +violation + + + align:start position:0% +violation +um so here's a note of the paper we'll + + align:start position:0% +um so here's a note of the paper we'll + + + align:start position:0% +um so here's a note of the paper we'll +have another discussion of this + + align:start position:0% +have another discussion of this + + + align:start position:0% +have another discussion of this +in class by student presentation um + + align:start position:0% +in class by student presentation um + + + align:start position:0% +in class by student presentation um +croning and fitch here this is croning + + align:start position:0% +croning and fitch here this is croning + + + align:start position:0% +croning and fitch here this is croning +this is fitch it turns out that + + align:start position:0% + + + + align:start position:0% + +you know croning is actually a student + + align:start position:0% +you know croning is actually a student + + + align:start position:0% +you know croning is actually a student +or was a student of enrico fermi and + + align:start position:0% +or was a student of enrico fermi and + + + align:start position:0% +or was a student of enrico fermi and +also worked in chicago + + align:start position:0% +also worked in chicago + + + align:start position:0% +also worked in chicago +uh so there's quite an interesting + + align:start position:0% +uh so there's quite an interesting + + + align:start position:0% +uh so there's quite an interesting +family tree here + + align:start position:0% +family tree here + + + align:start position:0% +family tree here +uh to which also um gerry friedman + + align:start position:0% +uh to which also um gerry friedman + + + align:start position:0% +uh to which also um gerry friedman +belongs + + align:start position:0% +belongs + + + align:start position:0% +belongs +gerald friedman is a retired faculty at + + align:start position:0% +gerald friedman is a retired faculty at + + + align:start position:0% +gerald friedman is a retired faculty at +mit + + align:start position:0% +mit + + + align:start position:0% +mit +and discovered that protons are made out + + align:start position:0% +and discovered that protons are made out + + + align:start position:0% +and discovered that protons are made out +of cork so this is a very interesting + + align:start position:0% +of cork so this is a very interesting + + + align:start position:0% +of cork so this is a very interesting +family tree if you have some time you + + align:start position:0% +family tree if you have some time you + + + align:start position:0% +family tree if you have some time you +might want to look into this + + align:start position:0% +might want to look into this + + + align:start position:0% +might want to look into this +so here's the experiment so you take + + align:start position:0% +so here's the experiment so you take + + + align:start position:0% +so here's the experiment so you take +protons you dump them into a beam + + align:start position:0% +protons you dump them into a beam + + + align:start position:0% +protons you dump them into a beam +you try to with this um this magnet + + align:start position:0% +you try to with this um this magnet + + + align:start position:0% +you try to with this um this magnet +filter out the neutral component + + align:start position:0% +filter out the neutral component + + + align:start position:0% +filter out the neutral component +uh get rid of all photons and then let + + align:start position:0% +uh get rid of all photons and then let + + + align:start position:0% +uh get rid of all photons and then let +this beam decay + + align:start position:0% +this beam decay + + + align:start position:0% +this beam decay +uh and look in the spectrometer are for + + align:start position:0% +uh and look in the spectrometer are for + + + align:start position:0% +uh and look in the spectrometer are for +the case of two photons here's a bigger + + align:start position:0% +the case of two photons here's a bigger + + + align:start position:0% +the case of two photons here's a bigger +picture of the same spectrometer + + align:start position:0% +picture of the same spectrometer + + + align:start position:0% +picture of the same spectrometer +so this is basically a blow-up view of + + align:start position:0% +so this is basically a blow-up view of + + + align:start position:0% +so this is basically a blow-up view of +this uh so you have your + + align:start position:0% +this uh so you have your + + + align:start position:0% +this uh so you have your +your kaons and neutral kions coming in + + align:start position:0% +your kaons and neutral kions coming in + + + align:start position:0% +your kaons and neutral kions coming in +the k2's + + align:start position:0% +the k2's + + + align:start position:0% +the k2's +and then you look forward to indicates + + align:start position:0% +and then you look forward to indicates + + + align:start position:0% +and then you look forward to indicates +the instrumentation and how we actually + + align:start position:0% +the instrumentation and how we actually + + + align:start position:0% +the instrumentation and how we actually +would do this + + align:start position:0% +would do this + + + align:start position:0% +would do this +is part of later discussion that we + + align:start position:0% +is part of later discussion that we + + + align:start position:0% +is part of later discussion that we +actually talk about detectors + + align:start position:0% +actually talk about detectors + + + align:start position:0% +actually talk about detectors +in more detail all right + + align:start position:0% +in more detail all right + + + align:start position:0% +in more detail all right +so we just saw that cronin and fitch + + align:start position:0% +so we just saw that cronin and fitch + + + align:start position:0% +so we just saw that cronin and fitch +observed cp violation in mixture of + + align:start position:0% +observed cp violation in mixture of + + + align:start position:0% +observed cp violation in mixture of +states + + align:start position:0% +states + + + align:start position:0% +states +but we can also observe cp violation in + + align:start position:0% +but we can also observe cp violation in + + + align:start position:0% +but we can also observe cp violation in +direct decays + + align:start position:0% +direct decays + + + align:start position:0% +direct decays +and the classical example here is the + + align:start position:0% +and the classical example here is the + + + align:start position:0% +and the classical example here is the +case of the k long + + align:start position:0% +case of the k long + + + align:start position:0% +case of the k long +and semi electronic decay so semi + + align:start position:0% +and semi electronic decay so semi + + + align:start position:0% +and semi electronic decay so semi +electronic here means we have a decay + + align:start position:0% +electronic here means we have a decay + + + align:start position:0% +electronic here means we have a decay +of the k long the neutral particle in a + + align:start position:0% +of the k long the neutral particle in a + + + align:start position:0% +of the k long the neutral particle in a +charged ion + + align:start position:0% +charged ion + + + align:start position:0% +charged ion +an electron an antineutrino or + + align:start position:0% +an electron an antineutrino or + + + align:start position:0% +an electron an antineutrino or +it might very well also decay into + + align:start position:0% +it might very well also decay into + + + align:start position:0% +it might very well also decay into +a pi minus a positron and a neutrino + + align:start position:0% +a pi minus a positron and a neutrino + + + align:start position:0% +a pi minus a positron and a neutrino +and it turns out when you really count + + align:start position:0% +and it turns out when you really count + + + align:start position:0% +and it turns out when you really count +those events + + align:start position:0% +those events + + + align:start position:0% +those events +and perform a precise experiment that + + align:start position:0% +and perform a precise experiment that + + + align:start position:0% +and perform a precise experiment that +the k + + align:start position:0% +the k + + + align:start position:0% +the k +longs prefer the case to positrons over + + align:start position:0% +longs prefer the case to positrons over + + + align:start position:0% +longs prefer the case to positrons over +the case to electrons + + align:start position:0% +the case to electrons + + + align:start position:0% +the case to electrons +and so the fractional amount of this you + + align:start position:0% +and so the fractional amount of this you + + + align:start position:0% +and so the fractional amount of this you +know imbalance + + align:start position:0% +know imbalance + + + align:start position:0% +know imbalance +is 3 times 10 to the minus 3. so this is + + align:start position:0% +is 3 times 10 to the minus 3. so this is + + + align:start position:0% +is 3 times 10 to the minus 3. so this is +a rather small effect again + + align:start position:0% +a rather small effect again + + + align:start position:0% +a rather small effect again +of cp violation here indirect decays + + align:start position:0% +of cp violation here indirect decays + + + align:start position:0% +of cp violation here indirect decays +since then cp violation has also been + + align:start position:0% +since then cp violation has also been + + + align:start position:0% +since then cp violation has also been +shown + + align:start position:0% +shown + + + align:start position:0% +shown +in the decay of b mesons and the program + + align:start position:0% +in the decay of b mesons and the program + + + align:start position:0% +in the decay of b mesons and the program +of studying b mesons is a big part of + + align:start position:0% +of studying b mesons is a big part of + + + align:start position:0% +of studying b mesons is a big part of +the lhc experiment at the lh + + align:start position:0% +the lhc experiment at the lh + + + align:start position:0% +the lhc experiment at the lh +the lhc um there's also experiments in + + align:start position:0% +the lhc um there's also experiments in + + + align:start position:0% +the lhc um there's also experiments in +japan going on right now which study b + + align:start position:0% +japan going on right now which study b + + + align:start position:0% +japan going on right now which study b +maisons + + align:start position:0% +maisons + + + align:start position:0% +maisons +in order to learn further about b + + align:start position:0% +in order to learn further about b + + + align:start position:0% +in order to learn further about b +systems + + align:start position:0% +systems + + + align:start position:0% +systems +tests are also on the way for those who + + align:start position:0% +tests are also on the way for those who + + + align:start position:0% +tests are also on the way for those who +listen to the colloquium on monday + + align:start position:0% +listen to the colloquium on monday + + + align:start position:0% +listen to the colloquium on monday +in the neutrino sector so here we have a + + align:start position:0% +in the neutrino sector so here we have a + + + align:start position:0% +in the neutrino sector so here we have a +completely different part so not + + align:start position:0% +completely different part so not + + + align:start position:0% +completely different part so not +quarks are involved in weak interaction + + align:start position:0% +quarks are involved in weak interaction + + + align:start position:0% +quarks are involved in weak interaction +but neutrinos + + align:start position:0% +but neutrinos + + + align:start position:0% +but neutrinos +and so the question is whether or not in + + align:start position:0% +and so the question is whether or not in + + + align:start position:0% +and so the question is whether or not in +that sector of physics + + align:start position:0% +that sector of physics + + + align:start position:0% +that sector of physics +um that sector of the standard model the + + align:start position:0% +um that sector of the standard model the + + + align:start position:0% +um that sector of the standard model the +scp violation + + align:start position:0% +scp violation + + + align:start position:0% +scp violation +those are aspects we'll discuss later on + + align:start position:0% +those are aspects we'll discuss later on + + + align:start position:0% +those are aspects we'll discuss later on +when we talk about neutrinos + + align:start position:0% +when we talk about neutrinos + + + align:start position:0% +when we talk about neutrinos +specifically + + align:start position:0% +specifically + + + align:start position:0% +specifically +before i close a few more remarks + + align:start position:0% + + + + align:start position:0% + +on the meta antimatter + + align:start position:0% +on the meta antimatter + + + align:start position:0% +on the meta antimatter +symmetry so one of the biggest mysteries + + align:start position:0% +symmetry so one of the biggest mysteries + + + align:start position:0% +symmetry so one of the biggest mysteries +in physics i would claim + + align:start position:0% +in physics i would claim + + + align:start position:0% +in physics i would claim +the fact that we are even here to ask + + align:start position:0% +the fact that we are even here to ask + + + align:start position:0% +the fact that we are even here to ask +this question + + align:start position:0% +this question + + + align:start position:0% +this question +um so there is apparently more matter in + + align:start position:0% +um so there is apparently more matter in + + + align:start position:0% +um so there is apparently more matter in +the universe than anti-matter + + align:start position:0% +the universe than anti-matter + + + align:start position:0% +the universe than anti-matter +if you start from a big bang there was + + align:start position:0% +if you start from a big bang there was + + + align:start position:0% +if you start from a big bang there was +this symmetry and now we live in a + + align:start position:0% +this symmetry and now we live in a + + + align:start position:0% +this symmetry and now we live in a +universe which is dominated by meta + + align:start position:0% +universe which is dominated by meta + + + align:start position:0% +universe which is dominated by meta +so how is this possible so in + + align:start position:0% +so how is this possible so in + + + align:start position:0% +so how is this possible so in +1967 sakura proposed + + align:start position:0% +1967 sakura proposed + + + align:start position:0% +1967 sakura proposed +that this is possible in a system where + + align:start position:0% +that this is possible in a system where + + + align:start position:0% +that this is possible in a system where +by your number is violated so this is + + align:start position:0% +by your number is violated so this is + + + align:start position:0% +by your number is violated so this is +almost a trivial statement if you start + + align:start position:0% +almost a trivial statement if you start + + + align:start position:0% +almost a trivial statement if you start +from an equal number of baryons and + + align:start position:0% +from an equal number of baryons and + + + align:start position:0% +from an equal number of baryons and +antibiotics + + align:start position:0% +antibiotics + + + align:start position:0% +antibiotics +the sum is then zero are the barrier + + align:start position:0% +the sum is then zero are the barrier + + + align:start position:0% +the sum is then zero are the barrier +number the zero of this system + + align:start position:0% +number the zero of this system + + + align:start position:0% +number the zero of this system +and you end up in a system which is + + align:start position:0% +and you end up in a system which is + + + align:start position:0% +and you end up in a system which is +dominated by variance then barrier + + align:start position:0% +dominated by variance then barrier + + + align:start position:0% +dominated by variance then barrier +number needs to be violated but + + align:start position:0% +number needs to be violated but + + + align:start position:0% +number needs to be violated but +there's also the need of cp violation in + + align:start position:0% +there's also the need of cp violation in + + + align:start position:0% +there's also the need of cp violation in +this so + + align:start position:0% +this so + + + align:start position:0% +this so +we just saw that this is realized in + + align:start position:0% +we just saw that this is realized in + + + align:start position:0% +we just saw that this is realized in +nature but the amount of cp violation + + align:start position:0% +nature but the amount of cp violation + + + align:start position:0% +nature but the amount of cp violation +you observe in this system i just + + align:start position:0% +you observe in this system i just + + + align:start position:0% +you observe in this system i just +discussed + + align:start position:0% +discussed + + + align:start position:0% +discussed +it's not sufficient to explain the meta + + align:start position:0% +it's not sufficient to explain the meta + + + align:start position:0% +it's not sufficient to explain the meta +antimatter symmetry we observed in + + align:start position:0% +antimatter symmetry we observed in + + + align:start position:0% +antimatter symmetry we observed in +nature so there is more to be found + + align:start position:0% +nature so there is more to be found + + + align:start position:0% +nature so there is more to be found +there's new physics to be + + align:start position:0% +there's new physics to be + + + align:start position:0% +there's new physics to be +looked for um in in cp violation on this + + align:start position:0% +looked for um in in cp violation on this + + + align:start position:0% +looked for um in in cp violation on this +overall question + + align:start position:0% +overall question + + + align:start position:0% +overall question +and there's also need for um + + align:start position:0% +and there's also need for um + + + align:start position:0% +and there's also need for um +interactions to be out of + + align:start position:0% +interactions to be out of + + + align:start position:0% +interactions to be out of +equilibrium meaning that you don't you + + align:start position:0% +equilibrium meaning that you don't you + + + align:start position:0% +equilibrium meaning that you don't you +know revert the processes + + align:start position:0% +know revert the processes + + + align:start position:0% +know revert the processes +as you go forward + + align:start position:0% + + + + align:start position:0% + +um yet another point of discussion which + + align:start position:0% +um yet another point of discussion which + + + align:start position:0% +um yet another point of discussion which +i will not go into much detail + + align:start position:0% +i will not go into much detail + + + align:start position:0% +i will not go into much detail +in this lecture is that you know our + + align:start position:0% +in this lecture is that you know our + + + align:start position:0% +in this lecture is that you know our +quantum field theory which describes + + align:start position:0% +quantum field theory which describes + + + align:start position:0% +quantum field theory which describes +calls the standard model and describes + + align:start position:0% +calls the standard model and describes + + + align:start position:0% +calls the standard model and describes +the interaction of particles + + align:start position:0% +the interaction of particles + + + align:start position:0% +the interaction of particles +is invariant under cpt transformations + + align:start position:0% +is invariant under cpt transformations + + + align:start position:0% +is invariant under cpt transformations +that means that + + align:start position:0% +that means that + + + align:start position:0% +that means that +if cp is violated time reversal + + align:start position:0% +if cp is violated time reversal + + + align:start position:0% +if cp is violated time reversal +cannot uh be a symmetry so meaning going + + align:start position:0% +cannot uh be a symmetry so meaning going + + + align:start position:0% +cannot uh be a symmetry so meaning going +backwards and forward in time is not + + align:start position:0% +backwards and forward in time is not + + + align:start position:0% +backwards and forward in time is not +symmetric + + align:start position:0% +symmetric + + + align:start position:0% +symmetric +um and you can test this you can uh + + align:start position:0% +um and you can test this you can uh + + + align:start position:0% +um and you can test this you can uh +experiments which test + + align:start position:0% +experiments which test + + + align:start position:0% +experiments which test +that effect that fact you can also + + align:start position:0% +that effect that fact you can also + + + align:start position:0% +that effect that fact you can also +design experiments which test cpt + + align:start position:0% +design experiments which test cpt + + + align:start position:0% +design experiments which test cpt +directly so this is those are all + + align:start position:0% +directly so this is those are all + + + align:start position:0% +directly so this is those are all +interesting questions but we will not go + + align:start position:0% +interesting questions but we will not go + + + align:start position:0% +interesting questions but we will not go +into any of those in this + + align:start position:0% +into any of those in this + + + align:start position:0% +into any of those in this +in this lecture further we will however + + align:start position:0% +in this lecture further we will however + + + align:start position:0% +in this lecture further we will however +come back to understanding + + align:start position:0% +come back to understanding + + + align:start position:0% +come back to understanding +the origin of cp violation in the + + align:start position:0% +the origin of cp violation in the + + + align:start position:0% +the origin of cp violation in the +standard model + + align:start position:0% +standard model + + + align:start position:0% +standard model +and we talk in more detail about + + align:start position:0% +and we talk in more detail about + + + align:start position:0% +and we talk in more detail about +the weakened action + + align:start position:0% + + + + align:start position:0% + +you \ No newline at end of file diff --git a/pIwp65fPyYU.txt b/pIwp65fPyYU.txt new file mode 100644 index 0000000000000000000000000000000000000000..cfabb8fcc73a36ec2ecc6d604959236ecf0a3a6f --- /dev/null +++ b/pIwp65fPyYU.txt @@ -0,0 +1,7971 @@ +align:start position:0% + +The following content is provided under + + align:start position:0% +The following content is provided under + + + align:start position:0% +The following content is provided under +a Creative Common License. Your support + + align:start position:0% +a Creative Common License. Your support + + + align:start position:0% +a Creative Common License. Your support +will help MIT Open Courseware continue + + align:start position:0% +will help MIT Open Courseware continue + + + align:start position:0% +will help MIT Open Courseware continue +to offer highquality educational + + align:start position:0% +to offer highquality educational + + + align:start position:0% +to offer highquality educational +resources for free. To make a donation + + align:start position:0% +resources for free. To make a donation + + + align:start position:0% +resources for free. To make a donation +or to view additional materials from + + align:start position:0% +or to view additional materials from + + + align:start position:0% +or to view additional materials from +hundreds of MIT courses, visit MIT Open + + align:start position:0% +hundreds of MIT courses, visit MIT Open + + + align:start position:0% +hundreds of MIT courses, visit MIT Open +Courseware at ocw.mmit.edu. + + align:start position:0% + + + + align:start position:0% + +So, where are we in our grand list of + + align:start position:0% +So, where are we in our grand list of + + + align:start position:0% +So, where are we in our grand list of +our five types of problems? We've done + + align:start position:0% +our five types of problems? We've done + + + align:start position:0% +our five types of problems? We've done +weak acid in water, weak base in water, + + align:start position:0% +weak acid in water, weak base in water, + + + align:start position:0% +weak acid in water, weak base in water, +salt, and buffer. We only have two left. + + align:start position:0% +salt, and buffer. We only have two left. + + + align:start position:0% +salt, and buffer. We only have two left. +And that's what we're going to talk + + align:start position:0% +And that's what we're going to talk + + + align:start position:0% +And that's what we're going to talk +about right now. Strong acids and strong + + align:start position:0% +about right now. Strong acids and strong + + + align:start position:0% +about right now. Strong acids and strong +bases. And we're going to talk about + + align:start position:0% +bases. And we're going to talk about + + + align:start position:0% +bases. And we're going to talk about +them in uh in terms of acid base + + align:start position:0% +them in uh in terms of acid base + + + align:start position:0% +them in uh in terms of acid base +titrations. So, switching to today's + + align:start position:0% +titrations. So, switching to today's + + + align:start position:0% +titrations. So, switching to today's +handout. + + align:start position:0% +handout. + + + align:start position:0% +handout. +So, titrations, how many of you have + + align:start position:0% +So, titrations, how many of you have + + + align:start position:0% +So, titrations, how many of you have +done a titration in a laboratory? And + + align:start position:0% +done a titration in a laboratory? And + + + align:start position:0% +done a titration in a laboratory? And +like, okay, a lot a lot of people. Okay, + + align:start position:0% +like, okay, a lot a lot of people. Okay, + + + align:start position:0% +like, okay, a lot a lot of people. Okay, +if you haven't, I have to say you're not + + align:start position:0% +if you haven't, I have to say you're not + + + align:start position:0% +if you haven't, I have to say you're not +missing anything. It is + + align:start position:0% +missing anything. It is + + + align:start position:0% +missing anything. It is +really, it's like watching paint dry for + + align:start position:0% +really, it's like watching paint dry for + + + align:start position:0% +really, it's like watching paint dry for +most of the time during the titration. + + align:start position:0% +most of the time during the titration. + + + align:start position:0% +most of the time during the titration. +Okay. So here in an acidbased titration + + align:start position:0% +Okay. So here in an acidbased titration + + + align:start position:0% +Okay. So here in an acidbased titration +you have the addition of say a base of + + align:start position:0% +you have the addition of say a base of + + + align:start position:0% +you have the addition of say a base of +um known concentration to an acid of + + align:start position:0% +um known concentration to an acid of + + + align:start position:0% +um known concentration to an acid of +unknown + + align:start position:0% +unknown + + + align:start position:0% +unknown +concentration and you can use this by + + align:start position:0% +concentration and you can use this by + + + align:start position:0% +concentration and you can use this by +figuring out what volume you need um to + + align:start position:0% +figuring out what volume you need um to + + + align:start position:0% +figuring out what volume you need um to +reach the equivalence point. You can + + align:start position:0% +reach the equivalence point. You can + + + align:start position:0% +reach the equivalence point. You can +figure out the concentration of that + + align:start position:0% +figure out the concentration of that + + + align:start position:0% +figure out the concentration of that +acid or base. If you know the + + align:start position:0% +acid or base. If you know the + + + align:start position:0% +acid or base. If you know the +concentration of two things, you can + + align:start position:0% +concentration of two things, you can + + + align:start position:0% +concentration of two things, you can +often use it to figure out a Ka or + + align:start position:0% +often use it to figure out a Ka or + + + align:start position:0% +often use it to figure out a Ka or +calculate a molecular weight. Um but + + align:start position:0% +calculate a molecular weight. Um but + + + align:start position:0% +calculate a molecular weight. Um but +that's the uh the purpose of the + + align:start position:0% +that's the uh the purpose of the + + + align:start position:0% +that's the uh the purpose of the +titration. So let's look at the shape of + + align:start position:0% +titration. So let's look at the shape of + + + align:start position:0% +titration. So let's look at the shape of +these titration curves. So here we have + + align:start position:0% +these titration curves. So here we have + + + align:start position:0% +these titration curves. So here we have +a strong acid with a strong base. So we + + align:start position:0% +a strong acid with a strong base. So we + + + align:start position:0% +a strong acid with a strong base. So we +start out all we have at 0 is the strong + + align:start position:0% +start out all we have at 0 is the strong + + + align:start position:0% +start out all we have at 0 is the strong +acid. So we should have a very low pH + + align:start position:0% +acid. So we should have a very low pH + + + align:start position:0% +acid. So we should have a very low pH +here and then it should change slowly. + + align:start position:0% +here and then it should change slowly. + + + align:start position:0% +here and then it should change slowly. +Then it changes very rapidly and then + + align:start position:0% +Then it changes very rapidly and then + + + align:start position:0% +Then it changes very rapidly and then +changes slowly again. So what is this + + align:start position:0% +changes slowly again. So what is this + + + align:start position:0% +changes slowly again. So what is this +point S? So that point S has many many + + align:start position:0% +point S? So that point S has many many + + + align:start position:0% +point S? So that point S has many many +names which are all equivalent. It's + + align:start position:0% +names which are all equivalent. It's + + + align:start position:0% +names which are all equivalent. It's +called the equivalence point and we had + + align:start position:0% +called the equivalence point and we had + + + align:start position:0% +called the equivalence point and we had +uh the clicker question in the beginning + + align:start position:0% +uh the clicker question in the beginning + + + align:start position:0% +uh the clicker question in the beginning +was uh was mentioning that the S um here + + align:start position:0% +was uh was mentioning that the S um here + + + align:start position:0% +was uh was mentioning that the S um here +really stands for the stokometric point. + + align:start position:0% +really stands for the stokometric point. + + + align:start position:0% +really stands for the stokometric point. +Both of these are the same thing and + + align:start position:0% +Both of these are the same thing and + + + align:start position:0% +Both of these are the same thing and +it's the theoretical volume at which + + align:start position:0% +it's the theoretical volume at which + + + align:start position:0% +it's the theoretical volume at which +that base that you've added the number + + align:start position:0% +that base that you've added the number + + + align:start position:0% +that base that you've added the number +of moles of that base is equal to the + + align:start position:0% +of moles of that base is equal to the + + + align:start position:0% +of moles of that base is equal to the +number of moles of acid you have. So + + align:start position:0% +number of moles of acid you have. So + + + align:start position:0% +number of moles of acid you have. So +it's the the point at which the moles + + align:start position:0% +it's the the point at which the moles + + + align:start position:0% +it's the the point at which the moles +are equal to each other. And so that's + + align:start position:0% +are equal to each other. And so that's + + + align:start position:0% +are equal to each other. And so that's +stokometric one one or equivalence the + + align:start position:0% +stokometric one one or equivalence the + + + align:start position:0% +stokometric one one or equivalence the +moles are equivalent. So all these names + + align:start position:0% +moles are equivalent. So all these names + + + align:start position:0% +moles are equivalent. So all these names +are the same. They all mean the same + + align:start position:0% +are the same. They all mean the same + + + align:start position:0% +are the same. They all mean the same +thing. Don't get tricked if problems say + + align:start position:0% +thing. Don't get tricked if problems say + + + align:start position:0% +thing. Don't get tricked if problems say +one thing or the other. You also might + + align:start position:0% +one thing or the other. You also might + + + align:start position:0% +one thing or the other. You also might +hear endpoint. That's often the result + + align:start position:0% +hear endpoint. That's often the result + + + align:start position:0% +hear endpoint. That's often the result +of the experiment that you do um where + + align:start position:0% +of the experiment that you do um where + + + align:start position:0% +of the experiment that you do um where +you figure out what volume you needed to + + align:start position:0% +you figure out what volume you needed to + + + align:start position:0% +you figure out what volume you needed to +add to have a color change. So the way + + align:start position:0% +add to have a color change. So the way + + + align:start position:0% +add to have a color change. So the way +these work usually is you have this and + + align:start position:0% +these work usually is you have this and + + + align:start position:0% +these work usually is you have this and +you go drip drip drip and you look for a + + align:start position:0% +you go drip drip drip and you look for a + + + align:start position:0% +you go drip drip drip and you look for a +color change and at that point of the + + align:start position:0% +color change and at that point of the + + + align:start position:0% +color change and at that point of the +color change the first little hint of + + align:start position:0% +color change the first little hint of + + + align:start position:0% +color change the first little hint of +the color change is where you want to + + align:start position:0% +the color change is where you want to + + + align:start position:0% +the color change is where you want to +stop and measure the volume. Um but + + align:start position:0% +stop and measure the volume. Um but + + + align:start position:0% +stop and measure the volume. Um but +often you get very frustrated and you go + + align:start position:0% +often you get very frustrated and you go + + + align:start position:0% +often you get very frustrated and you go +from totally clear to you you're very + + align:start position:0% +from totally clear to you you're very + + + align:start position:0% +from totally clear to you you're very +very slow and you're right in here and + + align:start position:0% +very slow and you're right in here and + + + align:start position:0% +very slow and you're right in here and +then you can't stand it anymore and you + + align:start position:0% +then you can't stand it anymore and you + + + align:start position:0% +then you can't stand it anymore and you +jump right up here and you have to do it + + align:start position:0% +jump right up here and you have to do it + + + align:start position:0% +jump right up here and you have to do it +over and over again. But it should be + + align:start position:0% +over and over again. But it should be + + + align:start position:0% +over and over again. But it should be +that the end point should equal the + + align:start position:0% +that the end point should equal the + + + align:start position:0% +that the end point should equal the +equivalence point. So if you're good at + + align:start position:0% +equivalence point. So if you're good at + + + align:start position:0% +equivalence point. So if you're good at +these kinds of problems, you might be + + align:start position:0% +these kinds of problems, you might be + + + align:start position:0% +these kinds of problems, you might be +able to do a quick and dirty estimate + + align:start position:0% +able to do a quick and dirty estimate + + + align:start position:0% +able to do a quick and dirty estimate +what the value is and then figure out + + align:start position:0% +what the value is and then figure out + + + align:start position:0% +what the value is and then figure out +exactly how much you can add before you + + align:start position:0% +exactly how much you can add before you + + + align:start position:0% +exactly how much you can add before you +have to go slow. I.e. you can cheat, + + align:start position:0% +have to go slow. I.e. you can cheat, + + + align:start position:0% +have to go slow. I.e. you can cheat, +which I highly recommend in doing these + + align:start position:0% +which I highly recommend in doing these + + + align:start position:0% +which I highly recommend in doing these +kinds of uh laboratory exercises. So + + align:start position:0% +kinds of uh laboratory exercises. So + + + align:start position:0% +kinds of uh laboratory exercises. So +knowing how to do the math is really + + align:start position:0% +knowing how to do the math is really + + + align:start position:0% +knowing how to do the math is really +valuable of these problems. Okay, so we + + align:start position:0% +valuable of these problems. Okay, so we + + + align:start position:0% +valuable of these problems. Okay, so we +had a strong acid and a strong base. + + align:start position:0% +had a strong acid and a strong base. + + + align:start position:0% +had a strong acid and a strong base. +Here's the same curve for a strong base + + align:start position:0% +Here's the same curve for a strong base + + + align:start position:0% +Here's the same curve for a strong base +with a strong acid where we're adding + + align:start position:0% +with a strong acid where we're adding + + + align:start position:0% +with a strong acid where we're adding +the strong um acid in to the strong + + align:start position:0% +the strong um acid in to the strong + + + align:start position:0% +the strong um acid in to the strong +base. Um again, now we're going to start + + align:start position:0% +base. Um again, now we're going to start + + + align:start position:0% +base. Um again, now we're going to start +in the beginning at point zero before + + align:start position:0% +in the beginning at point zero before + + + align:start position:0% +in the beginning at point zero before +we've added any acid. We have a basic + + align:start position:0% +we've added any acid. We have a basic + + + align:start position:0% +we've added any acid. We have a basic +pH, goes slow, goes fast through point + + align:start position:0% +pH, goes slow, goes fast through point + + + align:start position:0% +pH, goes slow, goes fast through point +S, the equivalence point or stochometric + + align:start position:0% +S, the equivalence point or stochometric + + + align:start position:0% +S, the equivalence point or stochometric +point, and then goes slow again. So, how + + align:start position:0% +point, and then goes slow again. So, how + + + align:start position:0% +point, and then goes slow again. So, how +do you know? Um and the TAs are going to + + align:start position:0% +do you know? Um and the TAs are going to + + + align:start position:0% +do you know? Um and the TAs are going to +come down and uh do a little demo for + + align:start position:0% +come down and uh do a little demo for + + + align:start position:0% +come down and uh do a little demo for +you now about pH indicators. How do you + + align:start position:0% +you now about pH indicators. How do you + + + align:start position:0% +you now about pH indicators. How do you +know? And for those of you who have done + + align:start position:0% +know? And for those of you who have done + + + align:start position:0% +know? And for those of you who have done +um these have done these experiments in + + align:start position:0% +um these have done these experiments in + + + align:start position:0% +um these have done these experiments in +lab again, you have this color change. + + align:start position:0% +lab again, you have this color change. + + + align:start position:0% +lab again, you have this color change. +And usually you're clear, you go a + + align:start position:0% +And usually you're clear, you go a + + + align:start position:0% +And usually you're clear, you go a +little bit more, you have a little bit + + align:start position:0% +little bit more, you have a little bit + + + align:start position:0% +little bit more, you have a little bit +more, and you go to this. But as I was + + align:start position:0% +more, and you go to this. But as I was + + + align:start position:0% +more, and you go to this. But as I was +saying, what happens most of the time is + + align:start position:0% +saying, what happens most of the time is + + + align:start position:0% +saying, what happens most of the time is +you go from this clear all the way to + + align:start position:0% +you go from this clear all the way to + + + align:start position:0% +you go from this clear all the way to +the really dark and you have to start + + align:start position:0% +the really dark and you have to start + + + align:start position:0% +the really dark and you have to start +all over again because you missed uh the + + align:start position:0% +all over again because you missed uh the + + + align:start position:0% +all over again because you missed uh the +end point. So these pH indicators are + + align:start position:0% +end point. So these pH indicators are + + + align:start position:0% +end point. So these pH indicators are +able um to tell you that there's this + + align:start position:0% +able um to tell you that there's this + + + align:start position:0% +able um to tell you that there's this +change in + + align:start position:0% +change in + + + align:start position:0% +change in +pH. So um the TAS are going to show you + + align:start position:0% +pH. So um the TAS are going to show you + + + align:start position:0% +pH. So um the TAS are going to show you +um using a pH indicate. Come on in. Set + + align:start position:0% +um using a pH indicate. Come on in. Set + + + align:start position:0% +um using a pH indicate. Come on in. Set +up. I'm just talking while you set up um + + align:start position:0% +up. I'm just talking while you set up um + + + align:start position:0% +up. I'm just talking while you set up um +over there. You can use the document + + align:start position:0% +over there. You can use the document + + + align:start position:0% +over there. You can use the document +camera if you need it. + + align:start position:0% +camera if you need it. + + + align:start position:0% +camera if you need it. +So um so our demo TAS have uh used + + align:start position:0% +So um so our demo TAS have uh used + + + align:start position:0% +So um so our demo TAS have uh used +created a natural dye from red + + align:start position:0% +created a natural dye from red + + + align:start position:0% +created a natural dye from red +cabbage and this dye when it's in acid + + align:start position:0% +cabbage and this dye when it's in acid + + + align:start position:0% +cabbage and this dye when it's in acid +has a different slightly different + + align:start position:0% +has a different slightly different + + + align:start position:0% +has a different slightly different +structure than in base which causes it + + align:start position:0% +structure than in base which causes it + + + align:start position:0% +structure than in base which causes it +to have these two different colors. So + + align:start position:0% +to have these two different colors. So + + + align:start position:0% +to have these two different colors. So +we can tell which things are acidic and + + align:start position:0% +we can tell which things are acidic and + + + align:start position:0% +we can tell which things are acidic and +which things are basic by the color of + + align:start position:0% +which things are basic by the color of + + + align:start position:0% +which things are basic by the color of +the indicator. And I'm just gonna hand + + align:start position:0% +the indicator. And I'm just gonna hand + + + align:start position:0% +the indicator. And I'm just gonna hand +over a + + align:start position:0% +over a + + + align:start position:0% +over a +mic if it's on. + + align:start position:0% +mic if it's on. + + + align:start position:0% +mic if it's on. +Okay. Is it on? Yes. Yes. Okay. Great. + + align:start position:0% +Okay. Is it on? Yes. Yes. Okay. Great. + + + align:start position:0% +Okay. Is it on? Yes. Yes. Okay. Great. +Okay. So, we've got our solutions here. + + align:start position:0% +Okay. So, we've got our solutions here. + + + align:start position:0% +Okay. So, we've got our solutions here. +Um, this is lemon juice. We've got Did I + + align:start position:0% +Um, this is lemon juice. We've got Did I + + + align:start position:0% +Um, this is lemon juice. We've got Did I +put water in here? Right. Yeah. Water. + + align:start position:0% +put water in here? Right. Yeah. Water. + + + align:start position:0% +put water in here? Right. Yeah. Water. +Vinegar. I think maybe it was vinegar. + + align:start position:0% +Vinegar. I think maybe it was vinegar. + + + align:start position:0% +Vinegar. I think maybe it was vinegar. +Then this is + + align:start position:0% +Then this is + + + align:start position:0% +Then this is +vinegar. All right. Don't do that. Don't + + align:start position:0% +vinegar. All right. Don't do that. Don't + + + align:start position:0% +vinegar. All right. Don't do that. Don't +do that in lab. In the lab, you should + + align:start position:0% +do that in lab. In the lab, you should + + + align:start position:0% +do that in lab. In the lab, you should +always label your containers. Yes. Yes, + + align:start position:0% +always label your containers. Yes. Yes, + + + align:start position:0% +always label your containers. Yes. Yes, +indeed. Okay, so we've got lemon + + align:start position:0% +indeed. Okay, so we've got lemon + + + align:start position:0% +indeed. Okay, so we've got lemon +juice, water, vinegar, and ammonia. Did + + align:start position:0% +juice, water, vinegar, and ammonia. Did + + + align:start position:0% +juice, water, vinegar, and ammonia. Did +you add some water into that? Can you? + + align:start position:0% +you add some water into that? Can you? + + + align:start position:0% +you add some water into that? Can you? +Okay, so we're going to add a little bit + + align:start position:0% +Okay, so we're going to add a little bit + + + align:start position:0% +Okay, so we're going to add a little bit +of the p uh the indicator. The indicator + + align:start position:0% +of the p uh the indicator. The indicator + + + align:start position:0% +of the p uh the indicator. The indicator +came from red cabbage. So, the dye in + + align:start position:0% +came from red cabbage. So, the dye in + + + align:start position:0% +came from red cabbage. So, the dye in +the red cabbage uh it is a molecule that + + align:start position:0% +the red cabbage uh it is a molecule that + + + align:start position:0% +the red cabbage uh it is a molecule that +can be protetonated. And when the + + align:start position:0% +can be protetonated. And when the + + + align:start position:0% +can be protetonated. And when the +molecule gets proteinated, it um it + + align:start position:0% +molecule gets proteinated, it um it + + + align:start position:0% +molecule gets proteinated, it um it +basically its double bonds start moving + + align:start position:0% +basically its double bonds start moving + + + align:start position:0% +basically its double bonds start moving +around. And when you do that, um, it + + align:start position:0% +around. And when you do that, um, it + + + align:start position:0% +around. And when you do that, um, it +absorbs light differently. So, what + + align:start position:0% +absorbs light differently. So, what + + + align:start position:0% +absorbs light differently. So, what +we're going to see when we + + align:start position:0% +we're going to see when we + + + align:start position:0% +we're going to see when we +pour into there is that you'll see this, + + align:start position:0% +pour into there is that you'll see this, + + + align:start position:0% +pour into there is that you'll see this, +which is the, uh, the acid forms a nice + + align:start position:0% +which is the, uh, the acid forms a nice + + + align:start position:0% +which is the, uh, the acid forms a nice +pinkish color. Uh, this was the water, + + align:start position:0% +pinkish color. Uh, this was the water, + + + align:start position:0% +pinkish color. Uh, this was the water, +and when you pour it into the water, + + align:start position:0% +and when you pour it into the water, + + + align:start position:0% +and when you pour it into the water, +nothing really happens. Uh, and you can + + align:start position:0% +nothing really happens. Uh, and you can + + + align:start position:0% +nothing really happens. Uh, and you can +kind of understand that because the + + align:start position:0% +kind of understand that because the + + + align:start position:0% +kind of understand that because the +indicator itself is a water-based + + align:start position:0% +indicator itself is a water-based + + + align:start position:0% +indicator itself is a water-based +solution, so it's going to be purple. + + align:start position:0% +solution, so it's going to be purple. + + + align:start position:0% +solution, so it's going to be purple. +Uh, this was the vinegar and as we did + + align:start position:0% +Uh, this was the vinegar and as we did + + + align:start position:0% +Uh, this was the vinegar and as we did +last time, the vinegar um uh is is uh + + align:start position:0% +last time, the vinegar um uh is is uh + + + align:start position:0% +last time, the vinegar um uh is is uh +acidic and this was the ammonia. Um, and + + align:start position:0% +acidic and this was the ammonia. Um, and + + + align:start position:0% +acidic and this was the ammonia. Um, and +I'm gonna add a little bit of water. Can + + align:start position:0% +I'm gonna add a little bit of water. Can + + + align:start position:0% +I'm gonna add a little bit of water. Can +you add a little bit of water into this? + + align:start position:0% +you add a little bit of water into this? + + + align:start position:0% +you add a little bit of water into this? +You add it. Okay, great. Um, and then + + align:start position:0% +You add it. Okay, great. Um, and then + + + align:start position:0% +You add it. Okay, great. Um, and then +we're going to kind of do a little + + align:start position:0% +we're going to kind of do a little + + + align:start position:0% +we're going to kind of do a little +excursion here. Um, so what this is, + + align:start position:0% +excursion here. Um, so what this is, + + + align:start position:0% +excursion here. Um, so what this is, +this is a piece of Oh, it's cold. Piece + + align:start position:0% +this is a piece of Oh, it's cold. Piece + + + align:start position:0% +this is a piece of Oh, it's cold. Piece +of dry ice, which is just solid CO2. Um, + + align:start position:0% +of dry ice, which is just solid CO2. Um, + + + align:start position:0% +of dry ice, which is just solid CO2. Um, +and what I'm going to do is I'm going to + + align:start position:0% +and what I'm going to do is I'm going to + + + align:start position:0% +and what I'm going to do is I'm going to +drop it into there. So, this is um kind + + align:start position:0% +drop it into there. So, this is um kind + + + align:start position:0% +drop it into there. So, this is um kind +of a bit of a run. Yeah, I'll put it + + align:start position:0% +of a bit of a run. Yeah, I'll put it + + + align:start position:0% +of a bit of a run. Yeah, I'll put it +over here. Um so, this is an interesting + + align:start position:0% +over here. Um so, this is an interesting + + + align:start position:0% +over here. Um so, this is an interesting +demo because um Oh, that's not useful at + + align:start position:0% +demo because um Oh, that's not useful at + + + align:start position:0% +demo because um Oh, that's not useful at +all. Um actually, we can change Can we + + align:start position:0% +all. Um actually, we can change Can we + + + align:start position:0% +all. Um actually, we can change Can we +change that? Oh, maybe not. Oh, well, + + align:start position:0% +change that? Oh, maybe not. Oh, well, + + + align:start position:0% +change that? Oh, maybe not. Oh, well, +it's fine. Oh, man. I think we can do + + align:start position:0% +it's fine. Oh, man. I think we can do + + + align:start position:0% +it's fine. Oh, man. I think we can do +that, but this is beyond Well, well, + + align:start position:0% +that, but this is beyond Well, well, + + + align:start position:0% +that, but this is beyond Well, well, +what I was talking about was basically + + align:start position:0% +what I was talking about was basically + + + align:start position:0% +what I was talking about was basically +um when you drop the CO2 into this uh + + align:start position:0% +um when you drop the CO2 into this uh + + + align:start position:0% +um when you drop the CO2 into this uh +mixture, what's happening is that the + + align:start position:0% +mixture, what's happening is that the + + + align:start position:0% +mixture, what's happening is that the +CO2 actually uh decomposes and it forms + + align:start position:0% +CO2 actually uh decomposes and it forms + + + align:start position:0% +CO2 actually uh decomposes and it forms +something called carbonic acid. And good + + align:start position:0% +something called carbonic acid. And good + + + align:start position:0% +something called carbonic acid. And good +idea. + + align:start position:0% +idea. + + + align:start position:0% +idea. +uh carbonic acid um is is is an acid. So + + align:start position:0% +uh carbonic acid um is is is an acid. So + + + align:start position:0% +uh carbonic acid um is is is an acid. So +it will actually change uh the pH of the + + align:start position:0% +it will actually change uh the pH of the + + + align:start position:0% +it will actually change uh the pH of the +solution as we're talking and what this + + align:start position:0% +solution as we're talking and what this + + + align:start position:0% +solution as we're talking and what this +is relevant for is really for um uh + + align:start position:0% +is relevant for is really for um uh + + + align:start position:0% +is relevant for is really for um uh +global warming. So, we know about uh + + align:start position:0% +global warming. So, we know about uh + + + align:start position:0% +global warming. So, we know about uh +companies when they make I mean it's + + align:start position:0% +companies when they make I mean it's + + + align:start position:0% +companies when they make I mean it's +true when you have companies when they + + align:start position:0% +true when you have companies when they + + + align:start position:0% +true when you have companies when they +make um uh lots of different kinds of uh + + align:start position:0% +make um uh lots of different kinds of uh + + + align:start position:0% +make um uh lots of different kinds of uh +chemical compounds, they'll release CO2 + + align:start position:0% +chemical compounds, they'll release CO2 + + + align:start position:0% +chemical compounds, they'll release CO2 +into the atmosphere. And when the CO2 + + align:start position:0% +into the atmosphere. And when the CO2 + + + align:start position:0% +into the atmosphere. And when the CO2 +gets released, is it working or no + + align:start position:0% + + + + align:start position:0% + +upside down? That's even cooler. Look at + + align:start position:0% +upside down? That's even cooler. Look at + + + align:start position:0% +upside down? That's even cooler. Look at +that. So when the CO2 gets released into + + align:start position:0% +that. So when the CO2 gets released into + + + align:start position:0% +that. So when the CO2 gets released into +the atmosphere um is basically by + + align:start position:0% +the atmosphere um is basically by + + + align:start position:0% +the atmosphere um is basically by +Latier's principle you add all this CO2 + + align:start position:0% +Latier's principle you add all this CO2 + + + align:start position:0% +Latier's principle you add all this CO2 +it will force the reaction to start + + align:start position:0% +it will force the reaction to start + + + align:start position:0% +it will force the reaction to start +making carbonic acid and that will react + + align:start position:0% +making carbonic acid and that will react + + + align:start position:0% +making carbonic acid and that will react +with the water vapor and start making uh + + align:start position:0% +with the water vapor and start making uh + + + align:start position:0% +with the water vapor and start making uh +the water in the air very acidic. Um wow + + align:start position:0% +the water in the air very acidic. Um wow + + + align:start position:0% +the water in the air very acidic. Um wow +that's that's not useful at all and the + + align:start position:0% +that's that's not useful at all and the + + + align:start position:0% +that's that's not useful at all and the +color is not really changing but uh it + + align:start position:0% +color is not really changing but uh it + + + align:start position:0% +color is not really changing but uh it +was supposed to. + + align:start position:0% +was supposed to. + + + align:start position:0% +was supposed to. +I think we might have added too much + + align:start position:0% +I think we might have added too much + + + align:start position:0% +I think we might have added too much +space but we can keep an Yeah, we can + + align:start position:0% +space but we can keep an Yeah, we can + + + align:start position:0% +space but we can keep an Yeah, we can +keep an eye out and watch the color + + align:start position:0% +keep an eye out and watch the color + + + align:start position:0% +keep an eye out and watch the color +change while it's upside down which is + + align:start position:0% +change while it's upside down which is + + + align:start position:0% +change while it's upside down which is +really useful. really cool. Um, but + + align:start position:0% +really useful. really cool. Um, but + + + align:start position:0% +really useful. really cool. Um, but +anyway, yeah, that's how the indicator + + align:start position:0% +anyway, yeah, that's how the indicator + + + align:start position:0% +anyway, yeah, that's how the indicator +works. And, uh, yeah, that's that, I + + align:start position:0% +works. And, uh, yeah, that's that, I + + + align:start position:0% +works. And, uh, yeah, that's that, I +guess. Okay. All right. Okay. So, we'll + + align:start position:0% +guess. Okay. All right. Okay. So, we'll + + + align:start position:0% +guess. Okay. All right. Okay. So, we'll +we can leave this here. I'll switch the + + align:start position:0% +we can leave this here. I'll switch the + + + align:start position:0% +we can leave this here. I'll switch the +document camera back. + + align:start position:0% +document camera back. + + + align:start position:0% +document camera back. +And, uh, + + align:start position:0% +And, uh, + + + align:start position:0% +And, uh, +yeah, we might add a little more. I + + align:start position:0% +yeah, we might add a little more. I + + + align:start position:0% +yeah, we might add a little more. I +still, it's very, very concentrated + + align:start position:0% +still, it's very, very concentrated + + + align:start position:0% +still, it's very, very concentrated +still. See if we can get a little bit + + align:start position:0% +still. See if we can get a little bit + + + align:start position:0% +still. See if we can get a little bit +more without too much overflow. I think + + align:start position:0% +more without too much overflow. I think + + + align:start position:0% +more without too much overflow. I think +it's changing a little bit, actually. + + align:start position:0% +it's changing a little bit, actually. + + + align:start position:0% +it's changing a little bit, actually. +Yeah. + + align:start position:0% + + + + align:start position:0% + +All right, we'll we'll keep an eye on + + align:start position:0% +All right, we'll we'll keep an eye on + + + align:start position:0% +All right, we'll we'll keep an eye on +it. Okay, so let's go through and do uh + + align:start position:0% +it. Okay, so let's go through and do uh + + + align:start position:0% +it. Okay, so let's go through and do uh +calculate some points on a strong acid + + align:start position:0% +calculate some points on a strong acid + + + align:start position:0% +calculate some points on a strong acid +and base curve so we can check off those + + align:start position:0% +and base curve so we can check off those + + + align:start position:0% +and base curve so we can check off those +two final uh final types of uh pH + + align:start position:0% +two final uh final types of uh pH + + + align:start position:0% +two final uh final types of uh pH +problems. + + align:start position:0% +problems. + + + align:start position:0% +problems. +So here when we're calculating strong + + align:start position:0% +So here when we're calculating strong + + + align:start position:0% +So here when we're calculating strong +acid and strong bases if say we have a + + align:start position:0% +acid and strong bases if say we have a + + + align:start position:0% +acid and strong bases if say we have a +strong base that's u 2.5 molar um NaOH + + align:start position:0% +strong base that's u 2.5 molar um NaOH + + + align:start position:0% +strong base that's u 2.5 molar um NaOH +being titrated with a strong acid HCl at + + align:start position:0% +being titrated with a strong acid HCl at + + + align:start position:0% +being titrated with a strong acid HCl at +34 molar. + + align:start position:0% +34 molar. + + + align:start position:0% +34 molar. +So, first we want to calculate the pH um + + align:start position:0% +So, first we want to calculate the pH um + + + align:start position:0% +So, first we want to calculate the pH um +before the equivalence point when we've + + align:start position:0% +before the equivalence point when we've + + + align:start position:0% +before the equivalence point when we've +just added say five ms of our strong + + align:start position:0% +just added say five ms of our strong + + + align:start position:0% +just added say five ms of our strong +acid um to the solution which was 25 ms + + align:start position:0% +acid um to the solution which was 25 ms + + + align:start position:0% +acid um to the solution which was 25 ms +of our strong + + align:start position:0% +of our strong + + + align:start position:0% +of our strong +base. So, the first thing we're going to + + align:start position:0% +base. So, the first thing we're going to + + + align:start position:0% +base. So, the first thing we're going to +do is calculate how many moles of base + + align:start position:0% +do is calculate how many moles of base + + + align:start position:0% +do is calculate how many moles of base +that is. So, how many did we have in + + align:start position:0% +that is. So, how many did we have in + + + align:start position:0% +that is. So, how many did we have in +here? And since this base is strong, the + + align:start position:0% +here? And since this base is strong, the + + + align:start position:0% +here? And since this base is strong, the +number of moles of sodium hydroxide + + align:start position:0% +number of moles of sodium hydroxide + + + align:start position:0% +number of moles of sodium hydroxide +added equals the amount of hydroxide + + align:start position:0% +added equals the amount of hydroxide + + + align:start position:0% +added equals the amount of hydroxide +formed. That's pretty uh you know that's + + align:start position:0% +formed. That's pretty uh you know that's + + + align:start position:0% +formed. That's pretty uh you know that's +the definition of a strong base and it + + align:start position:0% +the definition of a strong base and it + + + align:start position:0% +the definition of a strong base and it +is hydroxide. So pretty much that's how + + align:start position:0% +is hydroxide. So pretty much that's how + + + align:start position:0% +is hydroxide. So pretty much that's how +much you get. Um so all we have to do is + + align:start position:0% +much you get. Um so all we have to do is + + + align:start position:0% +much you get. Um so all we have to do is +know how to calculate the number of + + align:start position:0% +know how to calculate the number of + + + align:start position:0% +know how to calculate the number of +moles and that is the uh volume that we + + align:start position:0% +moles and that is the uh volume that we + + + align:start position:0% +moles and that is the uh volume that we +had and we're converting that to liters + + align:start position:0% +had and we're converting that to liters + + + align:start position:0% +had and we're converting that to liters +um times our concentration. And so that + + align:start position:0% +um times our concentration. And so that + + + align:start position:0% +um times our concentration. And so that +gives us 6.25 25 * 10us3 moles. All + + align:start position:0% +gives us 6.25 25 * 10us3 moles. All + + + align:start position:0% +gives us 6.25 25 * 10us3 moles. All +right, so we know how many moles of O we + + align:start position:0% +right, so we know how many moles of O we + + + align:start position:0% +right, so we know how many moles of O we +have. Now we need to figure out how many + + align:start position:0% +have. Now we need to figure out how many + + + align:start position:0% +have. Now we need to figure out how many +moles of acid we added when we added um + + align:start position:0% +moles of acid we added when we added um + + + align:start position:0% +moles of acid we added when we added um +5 milliliters of the acid. So it's a + + align:start position:0% +5 milliliters of the acid. So it's a + + + align:start position:0% +5 milliliters of the acid. So it's a +strong acid. So the moles of acid added + + align:start position:0% +strong acid. So the moles of acid added + + + align:start position:0% +strong acid. So the moles of acid added +equal the number of moles of our um + + align:start position:0% +equal the number of moles of our um + + + align:start position:0% +equal the number of moles of our um +hydrronium ions that are formed. + + align:start position:0% +hydrronium ions that are formed. + + + align:start position:0% +hydrronium ions that are formed. +Definition of strong acid. And so we had + + align:start position:0% +Definition of strong acid. And so we had + + + align:start position:0% +Definition of strong acid. And so we had +five milliliters. we convert to liters + + align:start position:0% +five milliliters. we convert to liters + + + align:start position:0% +five milliliters. we convert to liters +times our concentration that gives us + + align:start position:0% +times our concentration that gives us + + + align:start position:0% +times our concentration that gives us +1.7 + + align:start position:0% +1.7 + + + align:start position:0% +1.7 +* 10us3 moles. So now we need to figure + + align:start position:0% +* 10us3 moles. So now we need to figure + + + align:start position:0% +* 10us3 moles. So now we need to figure +out how what the new amount of hydroxide + + align:start position:0% +out how what the new amount of hydroxide + + + align:start position:0% +out how what the new amount of hydroxide +is. So we had um we're going to convert + + align:start position:0% +is. So we had um we're going to convert + + + align:start position:0% +is. So we had um we're going to convert +some of our hydroxide will react with + + align:start position:0% +some of our hydroxide will react with + + + align:start position:0% +some of our hydroxide will react with +the amount of acid added because the + + align:start position:0% +the amount of acid added because the + + + align:start position:0% +the amount of acid added because the +stokometry is one to one. you're going + + align:start position:0% +stokometry is one to one. you're going + + + align:start position:0% +stokometry is one to one. you're going +to react equal numbers of O with + + align:start position:0% +to react equal numbers of O with + + + align:start position:0% +to react equal numbers of O with +H3O+. So we had 6.25* 10 the minus3 + + align:start position:0% +H3O+. So we had 6.25* 10 the minus3 + + + align:start position:0% +H3O+. So we had 6.25* 10 the minus3 +moles. We've added this number of moles + + align:start position:0% +moles. We've added this number of moles + + + align:start position:0% +moles. We've added this number of moles +of acid. So that many moles are going to + + align:start position:0% +of acid. So that many moles are going to + + + align:start position:0% +of acid. So that many moles are going to +are going to be con are going to be uh + + align:start position:0% +are going to be con are going to be uh + + + align:start position:0% +are going to be con are going to be uh +formed into salt and we're left with + + align:start position:0% +formed into salt and we're left with + + + align:start position:0% +formed into salt and we're left with +this minus this or 4.55 * 10us3 moles of + + align:start position:0% +this minus this or 4.55 * 10us3 moles of + + + align:start position:0% +this minus this or 4.55 * 10us3 moles of +O minus left. So at this point this is a + + align:start position:0% +O minus left. So at this point this is a + + + align:start position:0% +O minus left. So at this point this is a +strong base and water problem. All we + + align:start position:0% +strong base and water problem. All we + + + align:start position:0% +strong base and water problem. All we +have is hydroxide ions left in our + + align:start position:0% +have is hydroxide ions left in our + + + align:start position:0% +have is hydroxide ions left in our +solution. Um we've com we've uh + + align:start position:0% +solution. Um we've com we've uh + + + align:start position:0% +solution. Um we've com we've uh +converted all the acid that we added + + align:start position:0% +converted all the acid that we added + + + align:start position:0% +converted all the acid that we added +into a salt because it reacted with the + + align:start position:0% +into a salt because it reacted with the + + + align:start position:0% +into a salt because it reacted with the +base. And so this is strong base now. So + + align:start position:0% +base. And so this is strong base now. So + + + align:start position:0% +base. And so this is strong base now. So +for strong base all we have to do is + + align:start position:0% +for strong base all we have to do is + + + align:start position:0% +for strong base all we have to do is +calculate the marity and then calculate + + align:start position:0% +calculate the marity and then calculate + + + align:start position:0% +calculate the marity and then calculate +p and pH. So for marity we have the + + align:start position:0% +p and pH. So for marity we have the + + + align:start position:0% +p and pH. So for marity we have the +number of moles left 4.55* + + align:start position:0% +number of moles left 4.55* + + + align:start position:0% +number of moles left 4.55* +10us3 in our new volume and this is the + + align:start position:0% +10us3 in our new volume and this is the + + + align:start position:0% +10us3 in our new volume and this is the +part where people forget we had 25 mls + + align:start position:0% +part where people forget we had 25 mls + + + align:start position:0% +part where people forget we had 25 mls +we added five more so our new volume is + + align:start position:0% +we added five more so our new volume is + + + align:start position:0% +we added five more so our new volume is +30 ms um and so we have a new + + align:start position:0% +30 ms um and so we have a new + + + align:start position:0% +30 ms um and so we have a new +concentration and then from that we + + align:start position:0% +concentration and then from that we + + + align:start position:0% +concentration and then from that we +calculate pH. First we do P plugging in + + align:start position:0% +calculate pH. First we do P plugging in + + + align:start position:0% +calculate pH. First we do P plugging in +our hydroxide ion concentration and then + + align:start position:0% +our hydroxide ion concentration and then + + + align:start position:0% +our hydroxide ion concentration and then +calculate pH using the fact that at room + + align:start position:0% +calculate pH using the fact that at room + + + align:start position:0% +calculate pH using the fact that at room +temperature and all these problems are + + align:start position:0% +temperature and all these problems are + + + align:start position:0% +temperature and all these problems are +room temperature um that would be 14 + + align:start position:0% +room temperature um that would be 14 + + + align:start position:0% +room temperature um that would be 14 +minus the p is the pH and we have a + + align:start position:0% +minus the p is the pH and we have a + + + align:start position:0% +minus the p is the pH and we have a +point somewhere around here point B um + + align:start position:0% +point somewhere around here point B um + + + align:start position:0% +point somewhere around here point B um +on our titration curve after we've add 5 + + align:start position:0% +on our titration curve after we've add 5 + + + align:start position:0% +on our titration curve after we've add 5 +mls of strong acid our pH is still + + align:start position:0% +mls of strong acid our pH is still + + + align:start position:0% +mls of strong acid our pH is still +pretty basic 13.18 eight left. So, + + align:start position:0% +pretty basic 13.18 eight left. So, + + + align:start position:0% +pretty basic 13.18 eight left. So, +strong base and water problem. All you + + align:start position:0% +strong base and water problem. All you + + + align:start position:0% +strong base and water problem. All you +have to do is calculate the + + align:start position:0% +have to do is calculate the + + + align:start position:0% +have to do is calculate the +concentration of O minus, then the P, + + align:start position:0% +concentration of O minus, then the P, + + + align:start position:0% +concentration of O minus, then the P, +and then the pH. So, you don't have to + + align:start position:0% +and then the pH. So, you don't have to + + + align:start position:0% +and then the pH. So, you don't have to +have any of these minus and pluses in + + align:start position:0% +have any of these minus and pluses in + + + align:start position:0% +have any of these minus and pluses in +terms of setting up our tables and using + + align:start position:0% +terms of setting up our tables and using + + + align:start position:0% +terms of setting up our tables and using +Ka's and KBs. For a weak base and water + + align:start position:0% +Ka's and KBs. For a weak base and water + + + align:start position:0% +Ka's and KBs. For a weak base and water +problem, it's a concentration of + + align:start position:0% +problem, it's a concentration of + + + align:start position:0% +problem, it's a concentration of +hydroxide ion, + + align:start position:0% +hydroxide ion, + + + align:start position:0% +hydroxide ion, +PH. All right. So, let's move on now and + + align:start position:0% +PH. All right. So, let's move on now and + + + align:start position:0% +PH. All right. So, let's move on now and +think about what how what volume we + + align:start position:0% +think about what how what volume we + + + align:start position:0% +think about what how what volume we +would need to get to the stokometric + + align:start position:0% +would need to get to the stokometric + + + align:start position:0% +would need to get to the stokometric +point. So, you're often asked to + + align:start position:0% +point. So, you're often asked to + + + align:start position:0% +point. So, you're often asked to +calculate the volume of the strong acid + + align:start position:0% +calculate the volume of the strong acid + + + align:start position:0% +calculate the volume of the strong acid +needed to get to the stokometric or the + + align:start position:0% +needed to get to the stokometric or the + + + align:start position:0% +needed to get to the stokometric or the +equivalence point. And to do this, you + + align:start position:0% +equivalence point. And to do this, you + + + align:start position:0% +equivalence point. And to do this, you +need to think about how many moles of O + + align:start position:0% +need to think about how many moles of O + + + align:start position:0% +need to think about how many moles of O +you have because at the equivalence + + align:start position:0% +you have because at the equivalence + + + align:start position:0% +you have because at the equivalence +point, you have equal numbers of moles + + align:start position:0% +point, you have equal numbers of moles + + + align:start position:0% +point, you have equal numbers of moles +of acid. So, we had 6.25* 25 * 10us3 + + align:start position:0% +of acid. So, we had 6.25* 25 * 10us3 + + + align:start position:0% +of acid. So, we had 6.25* 25 * 10us3 +moles of O originally. And at the + + align:start position:0% +moles of O originally. And at the + + + align:start position:0% +moles of O originally. And at the +equivalence point then how many moles of + + align:start position:0% +equivalence point then how many moles of + + + align:start position:0% +equivalence point then how many moles of +acid do we need to + + align:start position:0% +acid do we need to + + + align:start position:0% +acid do we need to +add? We have to add that exact same + + align:start position:0% +add? We have to add that exact same + + + align:start position:0% +add? We have to add that exact same +number by definition. It's the + + align:start position:0% +number by definition. It's the + + + align:start position:0% +number by definition. It's the +equivalence point. It's the stokometric + + align:start position:0% +equivalence point. It's the stokometric + + + align:start position:0% +equivalence point. It's the stokometric +point. So if you know how many moles of + + align:start position:0% +point. So if you know how many moles of + + + align:start position:0% +point. So if you know how many moles of +the base you had, that's going to be + + align:start position:0% +the base you had, that's going to be + + + align:start position:0% +the base you had, that's going to be +equal to the moles of acid you need to + + align:start position:0% +equal to the moles of acid you need to + + + align:start position:0% +equal to the moles of acid you need to +add. So now we want to figure out the + + align:start position:0% +add. So now we want to figure out the + + + align:start position:0% +add. So now we want to figure out the +volume that that's needed. We know the + + align:start position:0% +volume that that's needed. We know the + + + align:start position:0% +volume that that's needed. We know the +number of moles that we need and we know + + align:start position:0% +number of moles that we need and we know + + + align:start position:0% +number of moles that we need and we know +the concentration. So now we just have + + align:start position:0% +the concentration. So now we just have + + + align:start position:0% +the concentration. So now we just have +to calculate the volume. So we have the + + align:start position:0% +to calculate the volume. So we have the + + + align:start position:0% +to calculate the volume. So we have the +moles. We use the concentration of the + + align:start position:0% +moles. We use the concentration of the + + + align:start position:0% +moles. We use the concentration of the +acid to figure out the volume that has + + align:start position:0% +acid to figure out the volume that has + + + align:start position:0% +acid to figure out the volume that has +to be + + align:start position:0% +to be + + + align:start position:0% +to be +added. All right. And what would be the + + align:start position:0% +added. All right. And what would be the + + + align:start position:0% +added. All right. And what would be the +pH at this + + align:start position:0% +pH at this + + + align:start position:0% +pH at this +point? It would be seven. + + align:start position:0% +point? It would be seven. + + + align:start position:0% +point? It would be seven. +So, this is a really fast question to + + align:start position:0% +So, this is a really fast question to + + + align:start position:0% +So, this is a really fast question to +ask on an exam because all you have to + + align:start position:0% +ask on an exam because all you have to + + + align:start position:0% +ask on an exam because all you have to +do is say if it was a weak if it was a + + align:start position:0% +do is say if it was a weak if it was a + + + align:start position:0% +do is say if it was a weak if it was a +strong base and a strong acid, they're + + align:start position:0% +strong base and a strong acid, they're + + + align:start position:0% +strong base and a strong acid, they're +going to form a neutral salt in water. + + align:start position:0% +going to form a neutral salt in water. + + + align:start position:0% +going to form a neutral salt in water. +So, the pH is seven and that's it. No + + align:start position:0% +So, the pH is seven and that's it. No + + + align:start position:0% +So, the pH is seven and that's it. No +calculations needed. You can answer that + + align:start position:0% +calculations needed. You can answer that + + + align:start position:0% +calculations needed. You can answer that +question very quickly. So, strong acid, + + align:start position:0% +question very quickly. So, strong acid, + + + align:start position:0% +question very quickly. So, strong acid, +strong base at the equivalence point, + + align:start position:0% +strong base at the equivalence point, + + + align:start position:0% +strong base at the equivalence point, +equal number of moles, you're going to + + align:start position:0% +equal number of moles, you're going to + + + align:start position:0% +equal number of moles, you're going to +get a salt that's neutral. + + align:start position:0% +get a salt that's neutral. + + + align:start position:0% +get a salt that's neutral. +And the salt here um we have HCl and + + align:start position:0% +And the salt here um we have HCl and + + + align:start position:0% +And the salt here um we have HCl and +NaOH is just NaCl salt. So remember at + + align:start position:0% +NaOH is just NaCl salt. So remember at + + + align:start position:0% +NaOH is just NaCl salt. So remember at +the equivalence point strong acid strong + + align:start position:0% +the equivalence point strong acid strong + + + align:start position:0% +the equivalence point strong acid strong +base the pH is going to be + + align:start position:0% +base the pH is going to be + + + align:start position:0% +base the pH is going to be +seven. All right. So now let's go down + + align:start position:0% +seven. All right. So now let's go down + + + align:start position:0% +seven. All right. So now let's go down +here and try point D. So just beyond the + + align:start position:0% +here and try point D. So just beyond the + + + align:start position:0% +here and try point D. So just beyond the +equivalence point. So here we want to + + align:start position:0% +equivalence point. So here we want to + + + align:start position:0% +equivalence point. So here we want to +calculate the pH after 1 mil of strong + + align:start position:0% +calculate the pH after 1 mil of strong + + + align:start position:0% +calculate the pH after 1 mil of strong +acid has been added after you have + + align:start position:0% +acid has been added after you have + + + align:start position:0% +acid has been added after you have +reached the equivalence point. So you + + align:start position:0% +reached the equivalence point. So you + + + align:start position:0% +reached the equivalence point. So you +went one mil too far in your titration + + align:start position:0% +went one mil too far in your titration + + + align:start position:0% +went one mil too far in your titration +and this is a strong acid and water + + align:start position:0% +and this is a strong acid and water + + + align:start position:0% +and this is a strong acid and water +problem. So our last uh type of problem + + align:start position:0% +problem. So our last uh type of problem + + + align:start position:0% +problem. So our last uh type of problem +here. So first what you want to do is + + align:start position:0% +here. So first what you want to do is + + + align:start position:0% +here. So first what you want to do is +figure out how many moles um u of this + + align:start position:0% +figure out how many moles um u of this + + + align:start position:0% +figure out how many moles um u of this +acid were added due to this one mil + + align:start position:0% +acid were added due to this one mil + + + align:start position:0% +acid were added due to this one mil +extra. And again, it's a strong acid. So + + align:start position:0% +extra. And again, it's a strong acid. So + + + align:start position:0% +extra. And again, it's a strong acid. So +the amount of acid added is going to be + + align:start position:0% +the amount of acid added is going to be + + + align:start position:0% +the amount of acid added is going to be +equal to the hydrononeium ion + + align:start position:0% +equal to the hydrononeium ion + + + align:start position:0% +equal to the hydrononeium ion +concentrations formed. Definition of + + align:start position:0% +concentrations formed. Definition of + + + align:start position:0% +concentrations formed. Definition of +strong acid. So we had a concentration + + align:start position:0% +strong acid. So we had a concentration + + + align:start position:0% +strong acid. So we had a concentration +of.34 of our strong acid. We added 1 mil + + align:start position:0% +of.34 of our strong acid. We added 1 mil + + + align:start position:0% +of.34 of our strong acid. We added 1 mil +extra. So we have 3.4 * + + align:start position:0% +extra. So we have 3.4 * + + + align:start position:0% +extra. So we have 3.4 * +10us4 moles of um + + align:start position:0% +10us4 moles of um + + + align:start position:0% +10us4 moles of um +H3+. Now we need to calculate the marity + + align:start position:0% +H3+. Now we need to calculate the marity + + + align:start position:0% +H3+. Now we need to calculate the marity +of that. And that's a clicker + + align:start position:0% + + + + align:start position:0% + +question. Okay. + + align:start position:0% + + + + align:start position:0% + +So the trick here is just to think about + + align:start position:0% +So the trick here is just to think about + + + align:start position:0% +So the trick here is just to think about +what is the volume at this + + align:start position:0% +what is the volume at this + + + align:start position:0% +what is the volume at this +point. And if we look over + + align:start position:0% +point. And if we look over + + + align:start position:0% +point. And if we look over +here, okay, do you want to just can + + align:start position:0% +here, okay, do you want to just can + + + align:start position:0% +here, okay, do you want to just can +bring it out? We're we're trying a + + align:start position:0% +bring it out? We're we're trying a + + + align:start position:0% +bring it out? We're we're trying a +couple of different uh variations of the + + align:start position:0% +couple of different uh variations of the + + + align:start position:0% +couple of different uh variations of the +uh the experiment over here. But + + align:start position:0% +uh the experiment over here. But + + + align:start position:0% +uh the experiment over here. But +uh just uh see if we can we can get it + + align:start position:0% +uh just uh see if we can we can get it + + + align:start position:0% +uh just uh see if we can we can get it +over time, but let's let's uh maybe + + align:start position:0% +over time, but let's let's uh maybe + + + align:start position:0% +over time, but let's let's uh maybe +we'll come back to that at the end. + + align:start position:0% +we'll come back to that at the end. + + + align:start position:0% +we'll come back to that at the end. +We'll just leave it there and see. Okay. + + align:start position:0% +We'll just leave it there and see. Okay. + + + align:start position:0% +We'll just leave it there and see. Okay. +or did you want to say something? + + align:start position:0% +or did you want to say something? + + + align:start position:0% +or did you want to say something? +All right. Why don't you talk about it + + align:start position:0% +All right. Why don't you talk about it + + + align:start position:0% +All right. Why don't you talk about it +briefly and then we'll look at the I + + align:start position:0% +briefly and then we'll look at the I + + + align:start position:0% +briefly and then we'll look at the I +mean, we we we did the experiment again + + align:start position:0% +mean, we we we did the experiment again + + + align:start position:0% +mean, we we we did the experiment again +kind of with a less concentrated + + align:start position:0% +kind of with a less concentrated + + + align:start position:0% +kind of with a less concentrated +solution. Added several pieces of dry + + align:start position:0% +solution. Added several pieces of dry + + + align:start position:0% +solution. Added several pieces of dry +ice and as you can see um the color + + align:start position:0% +ice and as you can see um the color + + + align:start position:0% +ice and as you can see um the color +Yeah, we can put it on the camera or we + + align:start position:0% +Yeah, we can put it on the camera or we + + + align:start position:0% +Yeah, we can put it on the camera or we +can't. It's fine. But the color is + + align:start position:0% +can't. It's fine. But the color is + + + align:start position:0% +can't. It's fine. But the color is +changing um very slowly, which is a lot + + align:start position:0% +changing um very slowly, which is a lot + + + align:start position:0% +changing um very slowly, which is a lot +slower than we expected it to change. + + align:start position:0% +slower than we expected it to change. + + + align:start position:0% +slower than we expected it to change. +But um you dilute the concentration and + + align:start position:0% +But um you dilute the concentration and + + + align:start position:0% +But um you dilute the concentration and +this is turning blue um and it will + + align:start position:0% +this is turning blue um and it will + + + align:start position:0% +this is turning blue um and it will +eventually turn kind of yellowish pink, + + align:start position:0% +eventually turn kind of yellowish pink, + + + align:start position:0% +eventually turn kind of yellowish pink, +which is when it will eventually become + + align:start position:0% +which is when it will eventually become + + + align:start position:0% +which is when it will eventually become +an acid. So we'll just leave that there. + + align:start position:0% +an acid. So we'll just leave that there. + + + align:start position:0% +an acid. So we'll just leave that there. +All right. Well, we'll keep an eye on it + + align:start position:0% +All right. Well, we'll keep an eye on it + + + align:start position:0% +All right. Well, we'll keep an eye on it +for the next few minutes. All right. So + + align:start position:0% +for the next few minutes. All right. So + + + align:start position:0% +for the next few minutes. All right. So +the trick here was to figure out the + + align:start position:0% +the trick here was to figure out the + + + align:start position:0% +the trick here was to figure out the +volume. So you had 25 ms to begin with. + + align:start position:0% +volume. So you had 25 ms to begin with. + + + align:start position:0% +volume. So you had 25 ms to begin with. +You needed 18.4 to get to the + + align:start position:0% +You needed 18.4 to get to the + + + align:start position:0% +You needed 18.4 to get to the +stokometric or the equivalence point. + + align:start position:0% +stokometric or the equivalence point. + + + align:start position:0% +stokometric or the equivalence point. +And then you had to add then you added + + align:start position:0% +And then you had to add then you added + + + align:start position:0% +And then you had to add then you added +one more past the equivalence point. And + + align:start position:0% +one more past the equivalence point. And + + + align:start position:0% +one more past the equivalence point. And +if you remember to add those three + + align:start position:0% +if you remember to add those three + + + align:start position:0% +if you remember to add those three +volumes together, then you will get the + + align:start position:0% +volumes together, then you will get the + + + align:start position:0% +volumes together, then you will get the +right concentration. And when you get + + align:start position:0% +right concentration. And when you get + + + align:start position:0% +right concentration. And when you get +the right concentration, the rest of the + + align:start position:0% +the right concentration, the rest of the + + + align:start position:0% +the right concentration, the rest of the +problem is very easy. Um and I'll just + + align:start position:0% +problem is very easy. Um and I'll just + + + align:start position:0% +problem is very easy. Um and I'll just +mention also uh significant figures + + align:start position:0% +mention also uh significant figures + + + align:start position:0% +mention also uh significant figures +here. We have three here because we had + + align:start position:0% +here. We have three here because we had + + + align:start position:0% +here. We have three here because we had +three there. Um and uh so then you just + + align:start position:0% +three there. Um and uh so then you just + + + align:start position:0% +three there. Um and uh so then you just +take the pH of this. This is the + + align:start position:0% +take the pH of this. This is the + + + align:start position:0% +take the pH of this. This is the +hydrononeium concentration and that will + + align:start position:0% +hydrononeium concentration and that will + + + align:start position:0% +hydrononeium concentration and that will +give your answer and it'll be pH2.116 + + align:start position:0% +give your answer and it'll be pH2.116 + + + align:start position:0% +give your answer and it'll be pH2.116 +um with all of those significant figures + + align:start position:0% +um with all of those significant figures + + + align:start position:0% +um with all of those significant figures +which you can never measure that + + align:start position:0% +which you can never measure that + + + align:start position:0% +which you can never measure that +accurately but nonetheless that's what + + align:start position:0% +accurately but nonetheless that's what + + + align:start position:0% +accurately but nonetheless that's what +the rules would tell us. Um so a strong + + align:start position:0% +the rules would tell us. Um so a strong + + + align:start position:0% +the rules would tell us. Um so a strong +acid in um water problem is just you + + align:start position:0% +acid in um water problem is just you + + + align:start position:0% +acid in um water problem is just you +just calculate the hydrronium ion + + align:start position:0% +just calculate the hydrronium ion + + + align:start position:0% +just calculate the hydrronium ion +concentration and then pH. So this is a + + align:start position:0% +concentration and then pH. So this is a + + + align:start position:0% +concentration and then pH. So this is a +pretty simple part. All right. So if we + + align:start position:0% +pretty simple part. All right. So if we + + + align:start position:0% +pretty simple part. All right. So if we +go back now um to our + + align:start position:0% +go back now um to our + + + align:start position:0% +go back now um to our +uh to our diagram, we've measured a + + align:start position:0% +uh to our diagram, we've measured a + + + align:start position:0% +uh to our diagram, we've measured a +couple parts. We measured point B and uh + + align:start position:0% +couple parts. We measured point B and uh + + + align:start position:0% +couple parts. We measured point B and uh +and so we had a pH of + + align:start position:0% +and so we had a pH of + + + align:start position:0% +and so we had a pH of +13.18. This was like a strong basin + + align:start position:0% +13.18. This was like a strong basin + + + align:start position:0% +13.18. This was like a strong basin +water problem. We measure at point S we + + align:start position:0% +water problem. We measure at point S we + + + align:start position:0% +water problem. We measure at point S we +calculated that we needed 18.4 mills of + + align:start position:0% +calculated that we needed 18.4 mills of + + + align:start position:0% +calculated that we needed 18.4 mills of +strong acid and our pH is seven. And so + + align:start position:0% +strong acid and our pH is seven. And so + + + align:start position:0% +strong acid and our pH is seven. And so +at to the trick to doing this problem + + align:start position:0% +at to the trick to doing this problem + + + align:start position:0% +at to the trick to doing this problem +was just to remember that the moles of + + align:start position:0% +was just to remember that the moles of + + + align:start position:0% +was just to remember that the moles of +strong acid equal the moles of strong + + align:start position:0% +strong acid equal the moles of strong + + + align:start position:0% +strong acid equal the moles of strong +base at this point. And then for point D + + align:start position:0% +base at this point. And then for point D + + + align:start position:0% +base at this point. And then for point D +one mil past the equivalence point the + + align:start position:0% +one mil past the equivalence point the + + + align:start position:0% +one mil past the equivalence point the +pH was + + align:start position:0% +pH was + + + align:start position:0% +pH was +2.116. And this is like a um strong acid + + align:start position:0% +2.116. And this is like a um strong acid + + + align:start position:0% +2.116. And this is like a um strong acid +and water problem. And notice how + + align:start position:0% +and water problem. And notice how + + + align:start position:0% +and water problem. And notice how +dramatic it is. Up here you're at pH7. + + align:start position:0% +dramatic it is. Up here you're at pH7. + + + align:start position:0% +dramatic it is. Up here you're at pH7. +You add one mil too much and you're + + align:start position:0% +You add one mil too much and you're + + + align:start position:0% +You add one mil too much and you're +already at pH2. So this is a very rapid + + align:start position:0% +already at pH2. So this is a very rapid + + + align:start position:0% +already at pH2. So this is a very rapid +change. This is why a lot of these + + align:start position:0% +change. This is why a lot of these + + + align:start position:0% +change. This is why a lot of these +titration experiments are so frustrating + + align:start position:0% +titration experiments are so frustrating + + + align:start position:0% +titration experiments are so frustrating +that you add a little bit too much and + + align:start position:0% +that you add a little bit too much and + + + align:start position:0% +that you add a little bit too much and +you're just way way way beyond the + + align:start position:0% +you're just way way way beyond the + + + align:start position:0% +you're just way way way beyond the +stoometric point. All right. So in one + + align:start position:0% +stoometric point. All right. So in one + + + align:start position:0% +stoometric point. All right. So in one +titration curve here we had three types + + align:start position:0% +titration curve here we had three types + + + align:start position:0% +titration curve here we had three types +of problems. But as we get into weak + + align:start position:0% +of problems. But as we get into weak + + + align:start position:0% +of problems. But as we get into weak +acid and weak base, which we'll do now, + + align:start position:0% +acid and weak base, which we'll do now, + + + align:start position:0% +acid and weak base, which we'll do now, +you'll see that a titration curve is + + align:start position:0% +you'll see that a titration curve is + + + align:start position:0% +you'll see that a titration curve is +actually all five types of problems. So + + align:start position:0% +actually all five types of problems. So + + + align:start position:0% +actually all five types of problems. So +this is why one wants to start problem + + align:start position:0% +this is why one wants to start problem + + + align:start position:0% +this is why one wants to start problem +set seven early. + + align:start position:0% +set seven early. + + + align:start position:0% +set seven early. +Okay, so we've done all of these now and + + align:start position:0% +Okay, so we've done all of these now and + + + align:start position:0% +Okay, so we've done all of these now and +now we can apply all of these types of + + align:start position:0% +now we can apply all of these types of + + + align:start position:0% +now we can apply all of these types of +problems while doing weak acid strong + + align:start position:0% +problems while doing weak acid strong + + + align:start position:0% +problems while doing weak acid strong +base part and we'll just start this and + + align:start position:0% +base part and we'll just start this and + + + align:start position:0% +base part and we'll just start this and +we'll continue it later. But let's go + + align:start position:0% +we'll continue it later. But let's go + + + align:start position:0% +we'll continue it later. But let's go +through the curves um now. + + align:start position:0% +through the curves um now. + + + align:start position:0% +through the curves um now. +So, um, this is in your handout. This is + + align:start position:0% +So, um, this is in your handout. This is + + + align:start position:0% +So, um, this is in your handout. This is +the curve for the weak acid and strong + + align:start position:0% +the curve for the weak acid and strong + + + align:start position:0% +the curve for the weak acid and strong +base. And I just want to remind you what + + align:start position:0% +base. And I just want to remind you what + + + align:start position:0% +base. And I just want to remind you what +we just talked about, which is strong + + align:start position:0% +we just talked about, which is strong + + + align:start position:0% +we just talked about, which is strong +acid and strong base. So, for weak acid + + align:start position:0% +acid and strong base. So, for weak acid + + + align:start position:0% +acid and strong base. So, for weak acid +and strong base, the curves look quite a + + align:start position:0% +and strong base, the curves look quite a + + + align:start position:0% +and strong base, the curves look quite a +bit different. So, here we start at a + + align:start position:0% +bit different. So, here we start at a + + + align:start position:0% +bit different. So, here we start at a +higher pH because it's a weak weak acid. + + align:start position:0% +higher pH because it's a weak weak acid. + + + align:start position:0% +higher pH because it's a weak weak acid. +Here's lower. It's a strong acid. Then + + align:start position:0% +Here's lower. It's a strong acid. Then + + + align:start position:0% +Here's lower. It's a strong acid. Then +we go up. the pH levels + + align:start position:0% +we go up. the pH levels + + + align:start position:0% +we go up. the pH levels +off and this is called the buffering + + align:start position:0% +off and this is called the buffering + + + align:start position:0% +off and this is called the buffering +region. There's no such buffering region + + align:start position:0% +region. There's no such buffering region + + + align:start position:0% +region. There's no such buffering region +with a strong acid strong base because + + align:start position:0% +with a strong acid strong base because + + + align:start position:0% +with a strong acid strong base because +strong acids and stone bases don't form + + align:start position:0% +strong acids and stone bases don't form + + + align:start position:0% +strong acids and stone bases don't form +good buffers. But weak acids and strong + + align:start position:0% +good buffers. But weak acids and strong + + + align:start position:0% +good buffers. But weak acids and strong +bases can generate good buffering region + + align:start position:0% +bases can generate good buffering region + + + align:start position:0% +bases can generate good buffering region +because a strong base can convert some + + align:start position:0% +because a strong base can convert some + + + align:start position:0% +because a strong base can convert some +of the weak acid to its conjugate weak + + align:start position:0% +of the weak acid to its conjugate weak + + + align:start position:0% +of the weak acid to its conjugate weak +base and that creates a buffer in this + + align:start position:0% +base and that creates a buffer in this + + + align:start position:0% +base and that creates a buffer in this +region. Then the pH starts to change + + align:start position:0% +region. Then the pH starts to change + + + align:start position:0% +region. Then the pH starts to change +again. It's constant in the buffering + + align:start position:0% +again. It's constant in the buffering + + + align:start position:0% +again. It's constant in the buffering +region. Starts to change again. You get + + align:start position:0% +region. Starts to change again. You get + + + align:start position:0% +region. Starts to change again. You get +to the equivalence point. The definition + + align:start position:0% +to the equivalence point. The definition + + + align:start position:0% +to the equivalence point. The definition +of equivalence points are the same. + + align:start position:0% +of equivalence points are the same. + + + align:start position:0% +of equivalence points are the same. +Equal number of moles of acids and base + + align:start position:0% +Equal number of moles of acids and base + + + align:start position:0% +Equal number of moles of acids and base +at the equivalence point. But now the + + align:start position:0% +at the equivalence point. But now the + + + align:start position:0% +at the equivalence point. But now the +equivalence point is not at pH7 anymore. + + align:start position:0% +equivalence point is not at pH7 anymore. + + + align:start position:0% +equivalence point is not at pH7 anymore. +It's greater than pH7 because we've + + align:start position:0% +It's greater than pH7 because we've + + + align:start position:0% +It's greater than pH7 because we've +converted our weak acid to its conjugate + + align:start position:0% +converted our weak acid to its conjugate + + + align:start position:0% +converted our weak acid to its conjugate +base. So up here we have conjugate base + + align:start position:0% +base. So up here we have conjugate base + + + align:start position:0% +base. So up here we have conjugate base +which makes it more basic. And so the pH + + align:start position:0% +which makes it more basic. And so the pH + + + align:start position:0% +which makes it more basic. And so the pH +is greater than seven. and then the + + align:start position:0% +is greater than seven. and then the + + + align:start position:0% +is greater than seven. and then the +curve goes up + + align:start position:0% +curve goes up + + + align:start position:0% +curve goes up +again. We also have something that's + + align:start position:0% +again. We also have something that's + + + align:start position:0% +again. We also have something that's +special for a weak uh weak with strong + + align:start position:0% +special for a weak uh weak with strong + + + align:start position:0% +special for a weak uh weak with strong +titration that doesn't exist with strong + + align:start position:0% +titration that doesn't exist with strong + + + align:start position:0% +titration that doesn't exist with strong +strong and that's called the half + + align:start position:0% +strong and that's called the half + + + align:start position:0% +strong and that's called the half +equivalence point. The half equivalence + + align:start position:0% +equivalence point. The half equivalence + + + align:start position:0% +equivalence point. The half equivalence +point is the point where half the volume + + align:start position:0% +point is the point where half the volume + + + align:start position:0% +point is the point where half the volume +and half the number of moles needed to + + align:start position:0% +and half the number of moles needed to + + + align:start position:0% +and half the number of moles needed to +reach the equivalence point have been + + align:start position:0% +reach the equivalence point have been + + + align:start position:0% +reach the equivalence point have been +added. So that's the half equivalence + + align:start position:0% +added. So that's the half equivalence + + + align:start position:0% +added. So that's the half equivalence +point. It's half of the equivalence + + align:start position:0% +point. It's half of the equivalence + + + align:start position:0% +point. It's half of the equivalence +point. All right. So, let's just look at + + align:start position:0% +point. All right. So, let's just look at + + + align:start position:0% +point. All right. So, let's just look at +these a couple of different points here + + align:start position:0% +these a couple of different points here + + + align:start position:0% +these a couple of different points here +um and look at at this um this figure + + align:start position:0% +um and look at at this um this figure + + + align:start position:0% +um and look at at this um this figure +here and we'll end with this. Um so, and + + align:start position:0% +here and we'll end with this. Um so, and + + + align:start position:0% +here and we'll end with this. Um so, and +uh and I'm just going to have my TAS + + align:start position:0% +uh and I'm just going to have my TAS + + + align:start position:0% +uh and I'm just going to have my TAS +come down and just help me with this + + align:start position:0% +come down and just help me with this + + + align:start position:0% +come down and just help me with this +this last part. Um so, let's see if we + + align:start position:0% +this last part. Um so, let's see if we + + + align:start position:0% +this last part. Um so, let's see if we +can get uh two more. Um we already have + + align:start position:0% +can get uh two more. Um we already have + + + align:start position:0% +can get uh two more. Um we already have +someone with a hat. You have a hat. We + + align:start position:0% +someone with a hat. You have a hat. We + + + align:start position:0% +someone with a hat. You have a hat. We +have uh two more TAs. + + align:start position:0% + + + + align:start position:0% + +All right. So, these are all weak acids + + align:start position:0% +All right. So, these are all weak acids + + + align:start position:0% +All right. So, these are all weak acids +over + + align:start position:0% +over + + + align:start position:0% +over +here. Um, so we have just our weak acids + + align:start position:0% +here. Um, so we have just our weak acids + + + align:start position:0% +here. Um, so we have just our weak acids +and we have four of them. Um, and so the + + align:start position:0% +and we have four of them. Um, and so the + + + align:start position:0% +and we have four of them. Um, and so the +TAs can come other TAs you want to come + + align:start position:0% +TAs can come other TAs you want to come + + + align:start position:0% +TAs can come other TAs you want to come +down can help out. This is volume equals + + align:start position:0% +down can help out. This is volume equals + + + align:start position:0% +down can help out. This is volume equals +zero. So, this is like a weak acid and + + align:start position:0% +zero. So, this is like a weak acid and + + + align:start position:0% +zero. So, this is like a weak acid and +water problem. So, now let's bring our + + align:start position:0% +water problem. So, now let's bring our + + + align:start position:0% +water problem. So, now let's bring our +moles of uh of strong base over here. + + align:start position:0% +moles of uh of strong base over here. + + + align:start position:0% +moles of uh of strong base over here. +So, now Amanda, you're a strong base. + + align:start position:0% +So, now Amanda, you're a strong base. + + + align:start position:0% +So, now Amanda, you're a strong base. +So, you're one. So, you're going to + + align:start position:0% +So, you're one. So, you're going to + + + align:start position:0% +So, you're one. So, you're going to +react just with one um with one of these + + align:start position:0% +react just with one um with one of these + + + align:start position:0% +react just with one um with one of these +uh con of these weak acids and + + align:start position:0% +uh con of these weak acids and + + + align:start position:0% +uh con of these weak acids and +deproinate it and form a conjugate base. + + align:start position:0% +deproinate it and form a conjugate base. + + + align:start position:0% +deproinate it and form a conjugate base. +There we go. And then you can you can go + + align:start position:0% +There we go. And then you can you can go + + + align:start position:0% +There we go. And then you can you can go +off and form your salt in water. All + + align:start position:0% +off and form your salt in water. All + + + align:start position:0% +off and form your salt in water. All +right. So, now we have a buffer + + align:start position:0% +right. So, now we have a buffer + + + align:start position:0% +right. So, now we have a buffer +situation. And we have a buffer + + align:start position:0% +situation. And we have a buffer + + + align:start position:0% +situation. And we have a buffer +situation when we have some conjugate + + align:start position:0% +situation when we have some conjugate + + + align:start position:0% +situation when we have some conjugate +acid and some conjugate base. We have a + + align:start position:0% +acid and some conjugate base. We have a + + + align:start position:0% +acid and some conjugate base. We have a +special type of category of buffer at + + align:start position:0% +special type of category of buffer at + + + align:start position:0% +special type of category of buffer at +the half equivalence point where you + + align:start position:0% +the half equivalence point where you + + + align:start position:0% +the half equivalence point where you +have half the conjugate acid, half the + + align:start position:0% +have half the conjugate acid, half the + + + align:start position:0% +have half the conjugate acid, half the +conjugate. So another mole of strong + + align:start position:0% +conjugate. So another mole of strong + + + align:start position:0% +conjugate. So another mole of strong +base comes in and deproenates one of our + + align:start position:0% +base comes in and deproenates one of our + + + align:start position:0% +base comes in and deproenates one of our +acids. So why don't you be Yeah. And you + + align:start position:0% +acids. So why don't you be Yeah. And you + + + align:start position:0% +acids. So why don't you be Yeah. And you +go off and form form a salt. And so then + + align:start position:0% +go off and form form a salt. And so then + + + align:start position:0% +go off and form form a salt. And so then +we have half the weak acid and half the + + align:start position:0% +we have half the weak acid and half the + + + align:start position:0% +we have half the weak acid and half the +conjugate base. Now as we go on, we're + + align:start position:0% +conjugate base. Now as we go on, we're + + + align:start position:0% +conjugate base. Now as we go on, we're +going to reach the equivalence point. + + align:start position:0% +going to reach the equivalence point. + + + align:start position:0% +going to reach the equivalence point. +And now we've added the amount of strong + + align:start position:0% +And now we've added the amount of strong + + + align:start position:0% +And now we've added the amount of strong +base that will fully deproinate our weak + + align:start position:0% +base that will fully deproinate our weak + + + align:start position:0% +base that will fully deproinate our weak +acid. So why don't we have two more + + align:start position:0% +acid. So why don't we have two more + + + align:start position:0% +acid. So why don't we have two more +strong bases come along and deproinate. + + align:start position:0% +strong bases come along and deproinate. + + + align:start position:0% +strong bases come along and deproinate. +And so now we have only weak bases left. + + align:start position:0% +And so now we have only weak bases left. + + + align:start position:0% +And so now we have only weak bases left. +They're just weak bases left because we + + align:start position:0% +They're just weak bases left because we + + + align:start position:0% +They're just weak bases left because we +added equal numbers of moles of our + + align:start position:0% +added equal numbers of moles of our + + + align:start position:0% +added equal numbers of moles of our +strong base as we had weak acid. So now + + align:start position:0% +strong base as we had weak acid. So now + + + align:start position:0% +strong base as we had weak acid. So now +we have conjugate base. So this is like + + align:start position:0% +we have conjugate base. So this is like + + + align:start position:0% +we have conjugate base. So this is like +a weak base in water problem. And then + + align:start position:0% +a weak base in water problem. And then + + + align:start position:0% +a weak base in water problem. And then +at the end if we add more strong base + + align:start position:0% +at the end if we add more strong base + + + align:start position:0% +at the end if we add more strong base +and a strong base comes over there's + + align:start position:0% +and a strong base comes over there's + + + align:start position:0% +and a strong base comes over there's +nothing to do. He's just strong base in + + align:start position:0% +nothing to do. He's just strong base in + + + align:start position:0% +nothing to do. He's just strong base in +solution. And so this is a strong base + + align:start position:0% +solution. And so this is a strong base + + + align:start position:0% +solution. And so this is a strong base +and water problem. So the point is one + + align:start position:0% +and water problem. So the point is one + + + align:start position:0% +and water problem. So the point is one +titration problem is really five + + align:start position:0% +titration problem is really five + + + align:start position:0% +titration problem is really five +different types of acid base problems. + + align:start position:0% +different types of acid base problems. + + + align:start position:0% +different types of acid base problems. +So start problem set seven early. See + + align:start position:0% +So start problem set seven early. See + + + align:start position:0% +So start problem set seven early. See +you on + + align:start position:0% +you on + + + align:start position:0% +you on +Wednesday. All right. Let's just take 10 + + align:start position:0% +Wednesday. All right. Let's just take 10 + + + align:start position:0% +Wednesday. All right. Let's just take 10 +more seconds. + + align:start position:0% + + + + align:start position:0% + +Okay, I have a feeling that more people + + align:start position:0% +Okay, I have a feeling that more people + + + align:start position:0% +Okay, I have a feeling that more people +understand how to do this, but it's just + + align:start position:0% +understand how to do this, but it's just + + + align:start position:0% +understand how to do this, but it's just +a matter of thinking about the sort of + + align:start position:0% +a matter of thinking about the sort of + + + align:start position:0% +a matter of thinking about the sort of +the sign of things. Um, so the the trick + + align:start position:0% +the sign of things. Um, so the the trick + + + align:start position:0% +the sign of things. Um, so the the trick +here, you have a pH of four, pKa of + + align:start position:0% +here, you have a pH of four, pKa of + + + align:start position:0% +here, you have a pH of four, pKa of +49. And so obviously it's the + + align:start position:0% +49. And so obviously it's the + + + align:start position:0% +49. And so obviously it's the +difference, but you have to think about + + align:start position:0% +difference, but you have to think about + + + align:start position:0% +difference, but you have to think about +if you're uh if you want the ratio to be + + align:start position:0% +if you're uh if you want the ratio to be + + + align:start position:0% +if you're uh if you want the ratio to be +a minus to a um which expression you're + + align:start position:0% +a minus to a um which expression you're + + + align:start position:0% +a minus to a um which expression you're +going to use here to give you the the + + align:start position:0% +going to use here to give you the the + + + align:start position:0% +going to use here to give you the the +correct uh the correct one. So um just + + align:start position:0% +correct uh the correct one. So um just + + + align:start position:0% +correct uh the correct one. So um just +pay attention to your sign. always show + + align:start position:0% +pay attention to your sign. always show + + + align:start position:0% +pay attention to your sign. always show +lot all your work on an exam. So today + + align:start position:0% +lot all your work on an exam. So today + + + align:start position:0% +lot all your work on an exam. So today +we're going to finish the lecture notes + + align:start position:0% +we're going to finish the lecture notes + + + align:start position:0% +we're going to finish the lecture notes +from last time on titrations, continue + + align:start position:0% +from last time on titrations, continue + + + align:start position:0% +from last time on titrations, continue +with titrations and toward the end of + + align:start position:0% +with titrations and toward the end of + + + align:start position:0% +with titrations and toward the end of +the class we're going to start the next + + align:start position:0% +the class we're going to start the next + + + align:start position:0% +the class we're going to start the next +unit which is oxidation reduction. So we + + align:start position:0% +unit which is oxidation reduction. So we + + + align:start position:0% +unit which is oxidation reduction. So we +want to take out uh lecture note 23 top + + align:start position:0% +want to take out uh lecture note 23 top + + + align:start position:0% +want to take out uh lecture note 23 top +of page four where we had this curve. + + align:start position:0% +of page four where we had this curve. + + + align:start position:0% +of page four where we had this curve. +So, as we were finishing last time, we + + align:start position:0% +So, as we were finishing last time, we + + + align:start position:0% +So, as we were finishing last time, we +saw the curve for a titration of a weak + + align:start position:0% +saw the curve for a titration of a weak + + + align:start position:0% +saw the curve for a titration of a weak +acid with a strong base. And this is the + + align:start position:0% +acid with a strong base. And this is the + + + align:start position:0% +acid with a strong base. And this is the +curve for a weak base that's being + + align:start position:0% +curve for a weak base that's being + + + align:start position:0% +curve for a weak base that's being +titrated with a strong acid. And drawing + + align:start position:0% +titrated with a strong acid. And drawing + + + align:start position:0% +titrated with a strong acid. And drawing +curves on an exam, that's one of my + + align:start position:0% +curves on an exam, that's one of my + + + align:start position:0% +curves on an exam, that's one of my +favorite exam questions. Um, so make + + align:start position:0% +favorite exam questions. Um, so make + + + align:start position:0% +favorite exam questions. Um, so make +sure you know how to draw these types of + + align:start position:0% +sure you know how to draw these types of + + + align:start position:0% +sure you know how to draw these types of +titrations. So, things that you should + + align:start position:0% +titrations. So, things that you should + + + align:start position:0% +titrations. So, things that you should +pay attention to in drawing them. if it + + align:start position:0% +pay attention to in drawing them. if it + + + align:start position:0% +pay attention to in drawing them. if it +is a weak base that's being titrated + + align:start position:0% +is a weak base that's being titrated + + + align:start position:0% +is a weak base that's being titrated +with a strong acid, you would expect + + align:start position:0% +with a strong acid, you would expect + + + align:start position:0% +with a strong acid, you would expect +that before you've added any + + align:start position:0% +that before you've added any + + + align:start position:0% +that before you've added any +acid that you're going to have a basic + + align:start position:0% +acid that you're going to have a basic + + + align:start position:0% +acid that you're going to have a basic +pH. So at 0 here, you would expect a + + align:start position:0% +pH. So at 0 here, you would expect a + + + align:start position:0% +pH. So at 0 here, you would expect a +basic pH. + + align:start position:0% +basic pH. + + + align:start position:0% +basic pH. +So then the pH starts decreasing as + + align:start position:0% +So then the pH starts decreasing as + + + align:start position:0% +So then the pH starts decreasing as +you're titrating in the strong acid and + + align:start position:0% +you're titrating in the strong acid and + + + align:start position:0% +you're titrating in the strong acid and +you go into this region of constant pH + + align:start position:0% +you go into this region of constant pH + + + align:start position:0% +you go into this region of constant pH +um where that's the buffering region. So + + align:start position:0% +um where that's the buffering region. So + + + align:start position:0% +um where that's the buffering region. So +the pH is changing very little. It + + align:start position:0% +the pH is changing very little. It + + + align:start position:0% +the pH is changing very little. It +plateaus. It's flat. So when you're + + align:start position:0% +plateaus. It's flat. So when you're + + + align:start position:0% +plateaus. It's flat. So when you're +drawing a region like this, make sure + + align:start position:0% +drawing a region like this, make sure + + + align:start position:0% +drawing a region like this, make sure +that in the curve it looks kind of flat + + align:start position:0% +that in the curve it looks kind of flat + + + align:start position:0% +that in the curve it looks kind of flat +because the idea of a buffering region + + align:start position:0% +because the idea of a buffering region + + + align:start position:0% +because the idea of a buffering region +is that the pH isn't changing much. Here + + align:start position:0% +is that the pH isn't changing much. Here + + + align:start position:0% +is that the pH isn't changing much. Here +you have the conjugate acid and the + + align:start position:0% +you have the conjugate acid and the + + + align:start position:0% +you have the conjugate acid and the +conjugate conjugate base. So it's a + + align:start position:0% +conjugate conjugate base. So it's a + + + align:start position:0% +conjugate conjugate base. So it's a +buffer-like problem. Then when you get + + align:start position:0% +buffer-like problem. Then when you get + + + align:start position:0% +buffer-like problem. Then when you get +out of that buffering region, the pH + + align:start position:0% +out of that buffering region, the pH + + + align:start position:0% +out of that buffering region, the pH +drops rapidly, which is often one of the + + align:start position:0% +drops rapidly, which is often one of the + + + align:start position:0% +drops rapidly, which is often one of the +funs in doing these titrations in lab. + + align:start position:0% +funs in doing these titrations in lab. + + + align:start position:0% +funs in doing these titrations in lab. +Nothing's changing. Nothing's changing. + + align:start position:0% +Nothing's changing. Nothing's changing. + + + align:start position:0% +Nothing's changing. Nothing's changing. +Nothing changing. And all of a sudden, + + align:start position:0% +Nothing changing. And all of a sudden, + + + align:start position:0% +Nothing changing. And all of a sudden, +you're down here. Um, so at the + + align:start position:0% +you're down here. Um, so at the + + + align:start position:0% +you're down here. Um, so at the +equivalence point here, the equivalence + + align:start position:0% +equivalence point here, the equivalence + + + align:start position:0% +equivalence point here, the equivalence +point is going to be below pH7 because + + align:start position:0% +point is going to be below pH7 because + + + align:start position:0% +point is going to be below pH7 because +at this point you have added the same + + align:start position:0% +at this point you have added the same + + + align:start position:0% +at this point you have added the same +number of moles of acid as the weak + + align:start position:0% +number of moles of acid as the weak + + + align:start position:0% +number of moles of acid as the weak +base. So you've converted all of the + + align:start position:0% +base. So you've converted all of the + + + align:start position:0% +base. So you've converted all of the +weak base to its conjugate acid. So the + + align:start position:0% +weak base to its conjugate acid. So the + + + align:start position:0% +weak base to its conjugate acid. So the +pH is below seven and then it drops off + + align:start position:0% +pH is below seven and then it drops off + + + align:start position:0% +pH is below seven and then it drops off +rapidly. So again in these titration + + align:start position:0% +rapidly. So again in these titration + + + align:start position:0% +rapidly. So again in these titration +problems there really five different + + align:start position:0% +problems there really five different + + + align:start position:0% +problems there really five different +types of problems within them. When you + + align:start position:0% +types of problems within them. When you + + + align:start position:0% +types of problems within them. When you +have the volume of zero it's a weak + + align:start position:0% +have the volume of zero it's a weak + + + align:start position:0% +have the volume of zero it's a weak +basin water problem. In this buffering + + align:start position:0% +basin water problem. In this buffering + + + align:start position:0% +basin water problem. In this buffering +region here it's a buffer problem. And + + align:start position:0% +region here it's a buffer problem. And + + + align:start position:0% +region here it's a buffer problem. And +there's a special kind of buffer problem + + align:start position:0% +there's a special kind of buffer problem + + + align:start position:0% +there's a special kind of buffer problem +at the half equivalence point where the + + align:start position:0% +at the half equivalence point where the + + + align:start position:0% +at the half equivalence point where the +number of moles of the conjugate acid + + align:start position:0% +number of moles of the conjugate acid + + + align:start position:0% +number of moles of the conjugate acid +formed equal the number of moles of + + align:start position:0% +formed equal the number of moles of + + + align:start position:0% +formed equal the number of moles of +base. And then we get to the equivalence + + align:start position:0% +base. And then we get to the equivalence + + + align:start position:0% +base. And then we get to the equivalence +point and now we've converted all the + + align:start position:0% +point and now we've converted all the + + + align:start position:0% +point and now we've converted all the +weak base to its conjugate acid. So this + + align:start position:0% +weak base to its conjugate acid. So this + + + align:start position:0% +weak base to its conjugate acid. So this +is just a weak acid and water problem. + + align:start position:0% +is just a weak acid and water problem. + + + align:start position:0% +is just a weak acid and water problem. +And then down here it's a strong acid + + align:start position:0% +And then down here it's a strong acid + + + align:start position:0% +And then down here it's a strong acid +and water problem. So again, the trick + + align:start position:0% +and water problem. So again, the trick + + + align:start position:0% +and water problem. So again, the trick +in doing these is to recognize where you + + align:start position:0% +in doing these is to recognize where you + + + align:start position:0% +in doing these is to recognize where you +are in the curve and figure out what + + align:start position:0% +are in the curve and figure out what + + + align:start position:0% +are in the curve and figure out what +type of problem it is. Once you figure + + align:start position:0% +type of problem it is. Once you figure + + + align:start position:0% +type of problem it is. Once you figure +out what type of problem it is, it's + + align:start position:0% +out what type of problem it is, it's + + + align:start position:0% +out what type of problem it is, it's +usually not so bad to solve it because + + align:start position:0% +usually not so bad to solve it because + + + align:start position:0% +usually not so bad to solve it because +you can all figure out how to solve + + align:start position:0% +you can all figure out how to solve + + + align:start position:0% +you can all figure out how to solve +these five types of problems. It's + + align:start position:0% +these five types of problems. It's + + + align:start position:0% +these five types of problems. It's +recognizing what type of problem it is + + align:start position:0% +recognizing what type of problem it is + + + align:start position:0% +recognizing what type of problem it is +at various time during the titration. + + align:start position:0% +at various time during the titration. + + + align:start position:0% +at various time during the titration. +And in some of the uh problem set + + align:start position:0% +And in some of the uh problem set + + + align:start position:0% +And in some of the uh problem set +problems, you'll have all of the various + + align:start position:0% +problems, you'll have all of the various + + + align:start position:0% +problems, you'll have all of the various +points to do. But on an exam, you're + + align:start position:0% +points to do. But on an exam, you're + + + align:start position:0% +points to do. But on an exam, you're +going to just be thrown into the middle + + align:start position:0% +going to just be thrown into the middle + + + align:start position:0% +going to just be thrown into the middle +of a titration and have to think about + + align:start position:0% +of a titration and have to think about + + + align:start position:0% +of a titration and have to think about +where it is in the midst of titration. + + align:start position:0% +where it is in the midst of titration. + + + align:start position:0% +where it is in the midst of titration. +What type of problem is it? All right. + + align:start position:0% +What type of problem is it? All right. + + + align:start position:0% +What type of problem is it? All right. +So now we're going to go through and do + + align:start position:0% +So now we're going to go through and do + + + align:start position:0% +So now we're going to go through and do +an example work kind of point by point + + align:start position:0% +an example work kind of point by point + + + align:start position:0% +an example work kind of point by point +for a titration. And the titration we're + + align:start position:0% +for a titration. And the titration we're + + + align:start position:0% +for a titration. And the titration we're +going to do is a weak acid and a strong + + align:start position:0% +going to do is a weak acid and a strong + + + align:start position:0% +going to do is a weak acid and a strong +base. So that's the curve here. So we + + align:start position:0% +base. So that's the curve here. So we + + + align:start position:0% +base. So that's the curve here. So we +start at low pH and then go up. So the + + align:start position:0% +start at low pH and then go up. So the + + + align:start position:0% +start at low pH and then go up. So the +particular problem we're going to work + + align:start position:0% +particular problem we're going to work + + + align:start position:0% +particular problem we're going to work +and we're going to work all these points + + align:start position:0% +and we're going to work all these points + + + align:start position:0% +and we're going to work all these points +and we're going to have a bonus point E + + align:start position:0% +and we're going to have a bonus point E + + + align:start position:0% +and we're going to have a bonus point E +at the end um is formic acid and we have + + align:start position:0% +at the end um is formic acid and we have + + + align:start position:0% +at the end um is formic acid and we have +25 ms of 0.1 molar formic acid and we're + + align:start position:0% +25 ms of 0.1 molar formic acid and we're + + + align:start position:0% +25 ms of 0.1 molar formic acid and we're +titrating with a strong base sodium + + align:start position:0% +titrating with a strong base sodium + + + align:start position:0% +titrating with a strong base sodium +hydroxide 0.15 molar and you're often + + align:start position:0% +hydroxide 0.15 molar and you're often + + + align:start position:0% +hydroxide 0.15 molar and you're often +going to be given the Ka of the + + align:start position:0% +going to be given the Ka of the + + + align:start position:0% +going to be given the Ka of the +acid. So the first point A is volume + + align:start position:0% +acid. So the first point A is volume + + + align:start position:0% +acid. So the first point A is volume +zero. You haven't added any of your + + align:start position:0% +zero. You haven't added any of your + + + align:start position:0% +zero. You haven't added any of your +strong base + + align:start position:0% +strong base + + + align:start position:0% +strong base +yet. So you can write the expression for + + align:start position:0% +yet. So you can write the expression for + + + align:start position:0% +yet. So you can write the expression for +what's going on there. You have your + + align:start position:0% +what's going on there. You have your + + + align:start position:0% +what's going on there. You have your +acid plus water going to hydrronium ion + + align:start position:0% +acid plus water going to hydrronium ion + + + align:start position:0% +acid plus water going to hydrronium ion +concentration and you're forming the + + align:start position:0% +concentration and you're forming the + + + align:start position:0% +concentration and you're forming the +conjugate base of that weak acid. So + + align:start position:0% +conjugate base of that weak acid. So + + + align:start position:0% +conjugate base of that weak acid. So +this is again a weak acid problem. So + + align:start position:0% +this is again a weak acid problem. So + + + align:start position:0% +this is again a weak acid problem. So +you know how to do weak acid problems. + + align:start position:0% +you know how to do weak acid problems. + + + align:start position:0% +you know how to do weak acid problems. +So titrations are just the collection of + + align:start position:0% +So titrations are just the collection of + + + align:start position:0% +So titrations are just the collection of +problems we've already talked about how + + align:start position:0% +problems we've already talked about how + + + align:start position:0% +problems we've already talked about how +to do. So just uh very briefly, we'll go + + align:start position:0% +to do. So just uh very briefly, we'll go + + + align:start position:0% +to do. So just uh very briefly, we'll go +through this pretty fast at this point. + + align:start position:0% +through this pretty fast at this point. + + + align:start position:0% +through this pretty fast at this point. +Um so we have our weak acid in water. We + + align:start position:0% +Um so we have our weak acid in water. We + + + align:start position:0% +Um so we have our weak acid in water. We +had 0.1 molar and uh we had none of the + + align:start position:0% +had 0.1 molar and uh we had none of the + + + align:start position:0% +had 0.1 molar and uh we had none of the +other to begin with. So we're at zero + + align:start position:0% +other to begin with. So we're at zero + + + align:start position:0% +other to begin with. So we're at zero +volume here. So as the equilibrium is + + align:start position:0% +volume here. So as the equilibrium is + + + align:start position:0% +volume here. So as the equilibrium is +reached, we have 0.1 - x and x. So + + align:start position:0% +reached, we have 0.1 - x and x. So + + + align:start position:0% +reached, we have 0.1 - x and x. So +because this is a weak acid in water + + align:start position:0% +because this is a weak acid in water + + + align:start position:0% +because this is a weak acid in water +problem, we can use K a to solve the + + align:start position:0% +problem, we can use K a to solve the + + + align:start position:0% +problem, we can use K a to solve the +problem which is our acid ionization + + align:start position:0% +problem which is our acid ionization + + + align:start position:0% +problem which is our acid ionization +constant. It's 1.77 * 10us4 for this + + align:start position:0% +constant. It's 1.77 * 10us4 for this + + + align:start position:0% +constant. It's 1.77 * 10us4 for this +particular one. We can uh set this up. + + align:start position:0% +particular one. We can uh set this up. + + + align:start position:0% +particular one. We can uh set this up. +It's products over reactants at + + align:start position:0% +It's products over reactants at + + + align:start position:0% +It's products over reactants at +equilibrium. So x^2 over.1 + + align:start position:0% +equilibrium. So x^2 over.1 + + + align:start position:0% +equilibrium. So x^2 over.1 +um 0 - x. Again, water doesn't fit in. + + align:start position:0% +um 0 - x. Again, water doesn't fit in. + + + align:start position:0% +um 0 - x. Again, water doesn't fit in. +That's our solvent. So it's not in our + + align:start position:0% +That's our solvent. So it's not in our + + + align:start position:0% +That's our solvent. So it's not in our +expression. We can solve this with a + + align:start position:0% +expression. We can solve this with a + + + align:start position:0% +expression. We can solve this with a +quadratic or we can assume that X is + + align:start position:0% +quadratic or we can assume that X is + + + align:start position:0% +quadratic or we can assume that X is +small which again is a pretty good + + align:start position:0% +small which again is a pretty good + + + align:start position:0% +small which again is a pretty good +assumption usually for a weak acid + + align:start position:0% +assumption usually for a weak acid + + + align:start position:0% +assumption usually for a weak acid +problem. Um and by assuming X is small + + align:start position:0% +problem. Um and by assuming X is small + + + align:start position:0% +problem. Um and by assuming X is small +that means this minus X drops out. So + + align:start position:0% +that means this minus X drops out. So + + + align:start position:0% +that means this minus X drops out. So +we're saying X is small compared to the + + align:start position:0% +we're saying X is small compared to the + + + align:start position:0% +we're saying X is small compared to the +concentration that we started with and + + align:start position:0% +concentration that we started with and + + + align:start position:0% +concentration that we started with and +then we can solve for X. If we do that + + align:start position:0% +then we can solve for X. If we do that + + + align:start position:0% +then we can solve for X. If we do that +here, we get um + + align:start position:0% +here, we get um + + + align:start position:0% +here, we get um +0.004 uh + + align:start position:0% +0.004 uh + + + align:start position:0% +0.004 uh +21 and that we can check and we find + + align:start position:0% +21 and that we can check and we find + + + align:start position:0% +21 and that we can check and we find +that it is 4.2% of 0.1. So that's under + + align:start position:0% +that it is 4.2% of 0.1. So that's under + + + align:start position:0% +that it is 4.2% of 0.1. So that's under +5%. So that assumption is okay. Again, + + align:start position:0% +5%. So that assumption is okay. Again, + + + align:start position:0% +5%. So that assumption is okay. Again, +we're using the 5% rule. And then we can + + align:start position:0% +we're using the 5% rule. And then we can + + + align:start position:0% +we're using the 5% rule. And then we can +uh solve this. X is our hydrronium ion + + align:start position:0% +uh solve this. X is our hydrronium ion + + + align:start position:0% +uh solve this. X is our hydrronium ion +concentration. So we can plug that in + + align:start position:0% +concentration. So we can plug that in + + + align:start position:0% +concentration. So we can plug that in +and get an answer. But now I want you to + + align:start position:0% +and get an answer. But now I want you to + + + align:start position:0% +and get an answer. But now I want you to +tell me how many sigfigs this has. And + + align:start position:0% +tell me how many sigfigs this has. And + + + align:start position:0% +tell me how many sigfigs this has. And +to do that, you have to figure out how + + align:start position:0% +to do that, you have to figure out how + + + align:start position:0% +to do that, you have to figure out how +many sigfigs were actually in this + + align:start position:0% +many sigfigs were actually in this + + + align:start position:0% +many sigfigs were actually in this +number here. So you have to go back and + + align:start position:0% +number here. So you have to go back and + + + align:start position:0% +number here. So you have to go back and +look at the problem and figure out the + + align:start position:0% +look at the problem and figure out the + + + align:start position:0% +look at the problem and figure out the +total number of + + align:start position:0% + + + + align:start position:0% + +sigfigs. See how easy that was to fix. + + align:start position:0% +sigfigs. See how easy that was to fix. + + + align:start position:0% +sigfigs. See how easy that was to fix. +Um so it is two because this had two And + + align:start position:0% +Um so it is two because this had two And + + + align:start position:0% +Um so it is two because this had two And +the concentration was limiting here to + + align:start position:0% +the concentration was limiting here to + + + align:start position:0% +the concentration was limiting here to +two significant figures. So there were + + align:start position:0% +two significant figures. So there were + + + align:start position:0% +two significant figures. So there were +two here, which means there are two + + align:start position:0% +two here, which means there are two + + + align:start position:0% +two here, which means there are two +after the decimal point here. And I have + + align:start position:0% +after the decimal point here. And I have + + + align:start position:0% +after the decimal point here. And I have +to say, I was looking at problem set + + align:start position:0% +to say, I was looking at problem set + + + align:start position:0% +to say, I was looking at problem set +seven. And some of those problems are + + align:start position:0% +seven. And some of those problems are + + + align:start position:0% +seven. And some of those problems are +just like, if you love significant + + align:start position:0% +just like, if you love significant + + + align:start position:0% +just like, if you love significant +figures, they're a joy because you got + + align:start position:0% +figures, they're a joy because you got + + + align:start position:0% +figures, they're a joy because you got +adding and subtracting and then you had + + align:start position:0% +adding and subtracting and then you had + + + align:start position:0% +adding and subtracting and then you had +division and then you have logs. It is + + align:start position:0% +division and then you have logs. It is + + + align:start position:0% +division and then you have logs. It is +the triple whammy of sigfig love. All + + align:start position:0% +the triple whammy of sigfig love. All + + + align:start position:0% +the triple whammy of sigfig love. All +right. + + align:start position:0% +right. + + + align:start position:0% +right. +Um, so two after the decimal + + align:start position:0% +Um, so two after the decimal + + + align:start position:0% +Um, so two after the decimal +point. All right. So we have + + align:start position:0% +point. All right. So we have + + + align:start position:0% +point. All right. So we have +0.1. We have a pH that's acidic. That's + + align:start position:0% +0.1. We have a pH that's acidic. That's + + + align:start position:0% +0.1. We have a pH that's acidic. That's +good because at the beginning all we + + align:start position:0% +good because at the beginning all we + + + align:start position:0% +good because at the beginning all we +have is a weak acid. So we have a pH of + + align:start position:0% +have is a weak acid. So we have a pH of + + + align:start position:0% +have is a weak acid. So we have a pH of +2.38. So that's point A. So now let's + + align:start position:0% +2.38. So that's point A. So now let's + + + align:start position:0% +2.38. So that's point A. So now let's +look at this region here in the + + align:start position:0% +look at this region here in the + + + align:start position:0% +look at this region here in the +buffering region. And again the + + align:start position:0% +buffering region. And again the + + + align:start position:0% +buffering region. And again the +buffering region is when you have added + + align:start position:0% +buffering region is when you have added + + + align:start position:0% +buffering region is when you have added +volumes of your acid that are greater + + align:start position:0% +volumes of your acid that are greater + + + align:start position:0% +volumes of your acid that are greater +than zero but less than the volume + + align:start position:0% +than zero but less than the volume + + + align:start position:0% +than zero but less than the volume +needed to reach equilibrium. + + align:start position:0% +needed to reach equilibrium. + + + align:start position:0% +needed to reach equilibrium. +And so in this particular problem, we're + + align:start position:0% +And so in this particular problem, we're + + + align:start position:0% +And so in this particular problem, we're +going to calculate what happens when + + align:start position:0% +going to calculate what happens when + + + align:start position:0% +going to calculate what happens when +five ms of our strong base are added. So + + align:start position:0% +five ms of our strong base are added. So + + + align:start position:0% +five ms of our strong base are added. So +this is basically point B here. And + + align:start position:0% +this is basically point B here. And + + + align:start position:0% +this is basically point B here. And +because it's a strong base, it's going + + align:start position:0% +because it's a strong base, it's going + + + align:start position:0% +because it's a strong base, it's going +to react with all of our of the same + + align:start position:0% +to react with all of our of the same + + + align:start position:0% +to react with all of our of the same +number of moles of our weak acid. It's + + align:start position:0% +number of moles of our weak acid. It's + + + align:start position:0% +number of moles of our weak acid. It's +much stronger than the conjugate base. + + align:start position:0% +much stronger than the conjugate base. + + + align:start position:0% +much stronger than the conjugate base. +So it's going to react pretty much + + align:start position:0% +So it's going to react pretty much + + + align:start position:0% +So it's going to react pretty much +completely with this. So we can write + + align:start position:0% +completely with this. So we can write + + + align:start position:0% +completely with this. So we can write +out that the weak acid plus um our base + + align:start position:0% +out that the weak acid plus um our base + + + align:start position:0% +out that the weak acid plus um our base +are going to be converted over to the + + align:start position:0% +are going to be converted over to the + + + align:start position:0% +are going to be converted over to the +conjugate uh the conjugate base of this + + align:start position:0% +conjugate uh the conjugate base of this + + + align:start position:0% +conjugate uh the conjugate base of this +weak acid. So we just we can just figure + + align:start position:0% +weak acid. So we just we can just figure + + + align:start position:0% +weak acid. So we just we can just figure +out the moles and then subtract them to + + align:start position:0% +out the moles and then subtract them to + + + align:start position:0% +out the moles and then subtract them to +understand how much is uh is left and + + align:start position:0% +understand how much is uh is left and + + + align:start position:0% +understand how much is uh is left and +how much is being formed. So first then + + align:start position:0% +how much is being formed. So first then + + + align:start position:0% +how much is being formed. So first then +we need to figure out how many moles we + + align:start position:0% +we need to figure out how many moles we + + + align:start position:0% +we need to figure out how many moles we +had initially. So for our acid we had 25 + + align:start position:0% +had initially. So for our acid we had 25 + + + align:start position:0% +had initially. So for our acid we had 25 +ms of 0.10 molar. So we have 2.5 * 10us3 + + align:start position:0% +ms of 0.10 molar. So we have 2.5 * 10us3 + + + align:start position:0% +ms of 0.10 molar. So we have 2.5 * 10us3 +moles for our hydroxide our strong base + + align:start position:0% +moles for our hydroxide our strong base + + + align:start position:0% +moles for our hydroxide our strong base +we've added 5 ms and it was a.15 molar + + align:start position:0% +we've added 5 ms and it was a.15 molar + + + align:start position:0% +we've added 5 ms and it was a.15 molar +solution. So we have 75 * 10us3 moles. + + align:start position:0% +solution. So we have 75 * 10us3 moles. + + + align:start position:0% +solution. So we have 75 * 10us3 moles. +So now there's going to be this + + align:start position:0% +So now there's going to be this + + + align:start position:0% +So now there's going to be this +reaction. So we want to think about what + + align:start position:0% +reaction. So we want to think about what + + + align:start position:0% +reaction. So we want to think about what +happens after you have the reaction of + + align:start position:0% +happens after you have the reaction of + + + align:start position:0% +happens after you have the reaction of +the strong base um with the weak acid. + + align:start position:0% +the strong base um with the weak acid. + + + align:start position:0% +the strong base um with the weak acid. +And so just to emphasize this point, say + + align:start position:0% +And so just to emphasize this point, say + + + align:start position:0% +And so just to emphasize this point, say +we have eight moles of a of our acid + + align:start position:0% +we have eight moles of a of our acid + + + align:start position:0% +we have eight moles of a of our acid +here and we added just one mole of our + + align:start position:0% +here and we added just one mole of our + + + align:start position:0% +here and we added just one mole of our +strong base that will react, pull off, + + align:start position:0% +strong base that will react, pull off, + + + align:start position:0% +strong base that will react, pull off, +deproinate and form water and form the + + align:start position:0% +deproinate and form water and form the + + + align:start position:0% +deproinate and form water and form the +conjugate base. So net we had eight, we + + align:start position:0% +conjugate base. So net we had eight, we + + + align:start position:0% +conjugate base. So net we had eight, we +added one of the strong base. So we have + + align:start position:0% +added one of the strong base. So we have + + + align:start position:0% +added one of the strong base. So we have +seven left and we formed one of the + + align:start position:0% +seven left and we formed one of the + + + align:start position:0% +seven left and we formed one of the +conjugate base. And so I'm just uh + + align:start position:0% +conjugate base. And so I'm just uh + + + align:start position:0% +conjugate base. And so I'm just uh +showing this here because so often on + + align:start position:0% +showing this here because so often on + + + align:start position:0% +showing this here because so often on +exams I see people just plug the initial + + align:start position:0% +exams I see people just plug the initial + + + align:start position:0% +exams I see people just plug the initial +moles into uh the later part and they + + align:start position:0% +moles into uh the later part and they + + + align:start position:0% +moles into uh the later part and they +forget that there's a reaction happening + + align:start position:0% +forget that there's a reaction happening + + + align:start position:0% +forget that there's a reaction happening +and so I was hoping if I would show this + + align:start position:0% +and so I was hoping if I would show this + + + align:start position:0% +and so I was hoping if I would show this +I'm going to get people used to being + + align:start position:0% +I'm going to get people used to being + + + align:start position:0% +I'm going to get people used to being +thinking about okay I'm adding strong + + align:start position:0% +thinking about okay I'm adding strong + + + align:start position:0% +thinking about okay I'm adding strong +base what's happening how much is being + + align:start position:0% +base what's happening how much is being + + + align:start position:0% +base what's happening how much is being +converted and if you're not subtracting + + align:start position:0% +converted and if you're not subtracting + + + align:start position:0% +converted and if you're not subtracting +things there's a problem with the way + + align:start position:0% +things there's a problem with the way + + + align:start position:0% +things there's a problem with the way +you're doing the problem. All right. So + + align:start position:0% +you're doing the problem. All right. So + + + align:start position:0% +you're doing the problem. All right. So +here these are less easy numbers to + + align:start position:0% +here these are less easy numbers to + + + align:start position:0% +here these are less easy numbers to +visualize. Um 2.5 * 10us3 moles how much + + align:start position:0% +visualize. Um 2.5 * 10us3 moles how much + + + align:start position:0% +visualize. Um 2.5 * 10us3 moles how much +we had of our weak acid. We have added a + + align:start position:0% +we had of our weak acid. We have added a + + + align:start position:0% +we had of our weak acid. We have added a +strong base at 75 * + + align:start position:0% +strong base at 75 * + + + align:start position:0% +strong base at 75 * +10us3. So we have 1.75 * 10us3 moles of + + align:start position:0% +10us3. So we have 1.75 * 10us3 moles of + + + align:start position:0% +10us3. So we have 1.75 * 10us3 moles of +our acid left. So we subtract the amount + + align:start position:0% +our acid left. So we subtract the amount + + + align:start position:0% +our acid left. So we subtract the amount +that's converted due to the addition of + + align:start position:0% +that's converted due to the addition of + + + align:start position:0% +that's converted due to the addition of +the base. And so why don't you tell me + + align:start position:0% +the base. And so why don't you tell me + + + align:start position:0% +the base. And so why don't you tell me +how much then we're going to have of our + + align:start position:0% +how much then we're going to have of our + + + align:start position:0% +how much then we're going to have of our +conjugate base being formed. + + align:start position:0% + + + + align:start position:0% + +All right. So, I kind of tried to fool + + align:start position:0% +All right. So, I kind of tried to fool + + + align:start position:0% +All right. So, I kind of tried to fool +you there, but 75 70% of you um were not + + align:start position:0% +you there, but 75 70% of you um were not + + + align:start position:0% +you there, but 75 70% of you um were not +having it. Okay. So, here it's going to + + align:start position:0% +having it. Okay. So, here it's going to + + + align:start position:0% +having it. Okay. So, here it's going to +be equal to the number of moles of O + + align:start position:0% +be equal to the number of moles of O + + + align:start position:0% +be equal to the number of moles of O +that's added because that's how much is + + align:start position:0% +that's added because that's how much is + + + align:start position:0% +that's added because that's how much is +going to be converted. That's how much + + align:start position:0% +going to be converted. That's how much + + + align:start position:0% +going to be converted. That's how much +of the conjugate acid is converted to + + align:start position:0% +of the conjugate acid is converted to + + + align:start position:0% +of the conjugate acid is converted to +the conjugate + + align:start position:0% +the conjugate + + + align:start position:0% +the conjugate +base. All right. Now, we have moles. We + + align:start position:0% +base. All right. Now, we have moles. We + + + align:start position:0% +base. All right. Now, we have moles. We +need + + align:start position:0% +need + + + align:start position:0% +need +marity. If we're going to use a Ka to + + align:start position:0% +marity. If we're going to use a Ka to + + + align:start position:0% +marity. If we're going to use a Ka to +solve the problem because the expression + + align:start position:0% +solve the problem because the expression + + + align:start position:0% +solve the problem because the expression +for equilibrium constant has marity, not + + align:start position:0% +for equilibrium constant has marity, not + + + align:start position:0% +for equilibrium constant has marity, not +moles. So then in converting to marity, + + align:start position:0% +moles. So then in converting to marity, + + + align:start position:0% +moles. So then in converting to marity, +the thing you have to remember is the + + align:start position:0% +the thing you have to remember is the + + + align:start position:0% +the thing you have to remember is the +volume. So we had 25 mls to start with + + align:start position:0% +volume. So we had 25 mls to start with + + + align:start position:0% +volume. So we had 25 mls to start with +and now we've added five. So we need to + + align:start position:0% +and now we've added five. So we need to + + + align:start position:0% +and now we've added five. So we need to +make sure that we have the correct + + align:start position:0% +make sure that we have the correct + + + align:start position:0% +make sure that we have the correct +number of uh lers in our expression. So + + align:start position:0% +number of uh lers in our expression. So + + + align:start position:0% +number of uh lers in our expression. So +we can calculate 1.75 * 10us3 moles for + + align:start position:0% +we can calculate 1.75 * 10us3 moles for + + + align:start position:0% +we can calculate 1.75 * 10us3 moles for +our weak acid volume concentration of + + align:start position:0% +our weak acid volume concentration of + + + align:start position:0% +our weak acid volume concentration of +weak acid. We have 75 * 10us3 of our + + align:start position:0% +weak acid. We have 75 * 10us3 of our + + + align:start position:0% +weak acid. We have 75 * 10us3 of our +conjugate base and then we have a + + align:start position:0% +conjugate base and then we have a + + + align:start position:0% +conjugate base and then we have a +concentration there. Now there are two + + align:start position:0% +concentration there. Now there are two + + + align:start position:0% +concentration there. Now there are two +ways to solve this problem. + + align:start position:0% +ways to solve this problem. + + + align:start position:0% +ways to solve this problem. +And option one uses Ka. It doesn't + + align:start position:0% +And option one uses Ka. It doesn't + + + align:start position:0% +And option one uses Ka. It doesn't +involve Henderson Hasselbach. Option two + + align:start position:0% +involve Henderson Hasselbach. Option two + + + align:start position:0% +involve Henderson Hasselbach. Option two +will involve Henderson Hasselbach. And + + align:start position:0% +will involve Henderson Hasselbach. And + + + align:start position:0% +will involve Henderson Hasselbach. And +it's okay to use this because this is a + + align:start position:0% +it's okay to use this because this is a + + + align:start position:0% +it's okay to use this because this is a +buffer problem. So option one now for + + align:start position:0% +buffer problem. So option one now for + + + align:start position:0% +buffer problem. So option one now for +calculating point B. So we can set up + + align:start position:0% +calculating point B. So we can set up + + + align:start position:0% +calculating point B. So we can set up +this expression. And always remember + + align:start position:0% +this expression. And always remember + + + align:start position:0% +this expression. And always remember +you're talking about marity here. So + + align:start position:0% +you're talking about marity here. So + + + align:start position:0% +you're talking about marity here. So +don't put in your moles in this + + align:start position:0% +don't put in your moles in this + + + align:start position:0% +don't put in your moles in this +expression. Only put in marity. So + + align:start position:0% +expression. Only put in marity. So + + + align:start position:0% +expression. Only put in marity. So +that's why the volume is really + + align:start position:0% +that's why the volume is really + + + align:start position:0% +that's why the volume is really +important. So we can put in our + + align:start position:0% +important. So we can put in our + + + align:start position:0% +important. So we can put in our +concentration 0583 + + align:start position:0% +concentration 0583 + + + align:start position:0% +concentration 0583 +um and it'll be minus x for equilibrium + + align:start position:0% +um and it'll be minus x for equilibrium + + + align:start position:0% +um and it'll be minus x for equilibrium +plus x for our hydrononeium ion + + align:start position:0% +plus x for our hydrononeium ion + + + align:start position:0% +plus x for our hydrononeium ion +concentration and also our concentration + + align:start position:0% +concentration and also our concentration + + + align:start position:0% +concentration and also our concentration +of the conjugate base. + + align:start position:0% +of the conjugate base. + + + align:start position:0% +of the conjugate base. +0250 plus x. So this is like a buffer + + align:start position:0% +0250 plus x. So this is like a buffer + + + align:start position:0% +0250 plus x. So this is like a buffer +problem using option one. And so we can + + align:start position:0% +problem using option one. And so we can + + + align:start position:0% +problem using option one. And so we can +use Ka plug in our values. Here we have + + align:start position:0% +use Ka plug in our values. Here we have + + + align:start position:0% +use Ka plug in our values. Here we have +our conjugate base concentration at + + align:start position:0% +our conjugate base concentration at + + + align:start position:0% +our conjugate base concentration at +equilibrium times our hydrronium ion x + + align:start position:0% +equilibrium times our hydrronium ion x + + + align:start position:0% +equilibrium times our hydrronium ion x +over uh the equilibrium marity of our + + align:start position:0% +over uh the equilibrium marity of our + + + align:start position:0% +over uh the equilibrium marity of our +weak base. We can again assume x is + + align:start position:0% +weak base. We can again assume x is + + + align:start position:0% +weak base. We can again assume x is +small which drops out the plus x and the + + align:start position:0% +small which drops out the plus x and the + + + align:start position:0% +small which drops out the plus x and the +minus x. We solve for x. We get 4.13 * + + align:start position:0% +minus x. We solve for x. We get 4.13 * + + + align:start position:0% +minus x. We solve for x. We get 4.13 * +10us4. We can check the assumption and + + align:start position:0% +10us4. We can check the assumption and + + + align:start position:0% +10us4. We can check the assumption and +sure enough it's much smaller. + + align:start position:0% +sure enough it's much smaller. + + + align:start position:0% +sure enough it's much smaller. +1.7% 7% of of these two and you really + + align:start position:0% +1.7% 7% of of these two and you really + + + align:start position:0% +1.7% 7% of of these two and you really +only need to check one um the smaller + + align:start position:0% +only need to check one um the smaller + + + align:start position:0% +only need to check one um the smaller +one assumption's okay and we can + + align:start position:0% +one assumption's okay and we can + + + align:start position:0% +one assumption's okay and we can +calculate then by putting in X which is + + align:start position:0% +calculate then by putting in X which is + + + align:start position:0% +calculate then by putting in X which is +hydrronium ion concentration into the + + align:start position:0% +hydrronium ion concentration into the + + + align:start position:0% +hydrronium ion concentration into the +equation pH= minus log of the hydrronium + + align:start position:0% +equation pH= minus log of the hydrronium + + + align:start position:0% +equation pH= minus log of the hydrronium +ion concentration equals the pH + + align:start position:0% +ion concentration equals the pH + + + align:start position:0% +ion concentration equals the pH +3.38. We can also use Henderson + + align:start position:0% +3.38. We can also use Henderson + + + align:start position:0% +3.38. We can also use Henderson +Hustelbach because it's a buffer + + align:start position:0% +Hustelbach because it's a buffer + + + align:start position:0% +Hustelbach because it's a buffer +problem. It's allowed. You were given a + + align:start position:0% +problem. It's allowed. You were given a + + + align:start position:0% +problem. It's allowed. You were given a +Ka. You can calculate pKa minus the log + + align:start position:0% +Ka. You can calculate pKa minus the log + + + align:start position:0% +Ka. You can calculate pKa minus the log +of Ka and put that number in. Put in the + + align:start position:0% +of Ka and put that number in. Put in the + + + align:start position:0% +of Ka and put that number in. Put in the +concentrations that you determined. So + + align:start position:0% +concentrations that you determined. So + + + align:start position:0% +concentrations that you determined. So +you still need to subtract the moles. + + align:start position:0% +you still need to subtract the moles. + + + align:start position:0% +you still need to subtract the moles. +You can't skip that step. Um, but you + + align:start position:0% +You can't skip that step. Um, but you + + + align:start position:0% +You can't skip that step. Um, but you +can skip the volume step because when + + align:start position:0% +can skip the volume step because when + + + align:start position:0% +can skip the volume step because when +you use Henderson Hustelblock, the + + align:start position:0% +you use Henderson Hustelblock, the + + + align:start position:0% +you use Henderson Hustelblock, the +volume would cancel out. If you had + + align:start position:0% +volume would cancel out. If you had + + + align:start position:0% +volume would cancel out. If you had +moles per volume, moles per volume, the + + align:start position:0% +moles per volume, moles per volume, the + + + align:start position:0% +moles per volume, moles per volume, the +volume's the same. So, you can skip the + + align:start position:0% +volume's the same. So, you can skip the + + + align:start position:0% +volume's the same. So, you can skip the +calculating marity step here. That + + align:start position:0% +calculating marity step here. That + + + align:start position:0% +calculating marity step here. That +simplifies the problem and solve and you + + align:start position:0% +simplifies the problem and solve and you + + + align:start position:0% +simplifies the problem and solve and you +should get the exact same number or + + align:start position:0% +should get the exact same number or + + + align:start position:0% +should get the exact same number or +something was wrong. Both of these + + align:start position:0% +something was wrong. Both of these + + + align:start position:0% +something was wrong. Both of these +should work equally well. 3.38. + + align:start position:0% +should work equally well. 3.38. + + + align:start position:0% +should work equally well. 3.38. +But you'll often be asked to check the + + align:start position:0% +But you'll often be asked to check the + + + align:start position:0% +But you'll often be asked to check the +Henderson Hustelbach um assumption. And + + align:start position:0% +Henderson Hustelbach um assumption. And + + + align:start position:0% +Henderson Hustelbach um assumption. And +remember there was an assumption here + + align:start position:0% +remember there was an assumption here + + + align:start position:0% +remember there was an assumption here +because we solved the Henderson + + align:start position:0% +because we solved the Henderson + + + align:start position:0% +because we solved the Henderson +Hustelbach from an equation that use Ka, + + align:start position:0% +Hustelbach from an equation that use Ka, + + + align:start position:0% +Hustelbach from an equation that use Ka, +the equilibrium constant. So really this + + align:start position:0% +the equilibrium constant. So really this + + + align:start position:0% +the equilibrium constant. So really this +expression is at equilibrium, but we're + + align:start position:0% +expression is at equilibrium, but we're + + + align:start position:0% +expression is at equilibrium, but we're +plugging in values that are not at + + align:start position:0% +plugging in values that are not at + + + align:start position:0% +plugging in values that are not at +equilibrium. They're the initial values + + align:start position:0% +equilibrium. They're the initial values + + + align:start position:0% +equilibrium. They're the initial values +that we're putting into this equation. + + align:start position:0% +that we're putting into this equation. + + + align:start position:0% +that we're putting into this equation. +So we still need to check and we're + + align:start position:0% +So we still need to check and we're + + + align:start position:0% +So we still need to check and we're +using the 5% rule. So to check the + + align:start position:0% +using the 5% rule. So to check the + + + align:start position:0% +using the 5% rule. So to check the +Henderson Hustelbach then we have to + + align:start position:0% +Henderson Hustelbach then we have to + + + align:start position:0% +Henderson Hustelbach then we have to +back calculate pH of + + align:start position:0% +back calculate pH of + + + align:start position:0% +back calculate pH of +3.38 equals a hydrronium ion + + align:start position:0% +3.38 equals a hydrronium ion + + + align:start position:0% +3.38 equals a hydrronium ion +concentration of 4.2 * + + align:start position:0% +concentration of 4.2 * + + + align:start position:0% +concentration of 4.2 * +10us4 and then you want to check that + + align:start position:0% +10us4 and then you want to check that + + + align:start position:0% +10us4 and then you want to check that +that number is less than 5% of the + + align:start position:0% +that number is less than 5% of the + + + align:start position:0% +that number is less than 5% of the +smaller number and we checked that + + align:start position:0% +smaller number and we checked that + + + align:start position:0% +smaller number and we checked that +assumption when we looked at um option A + + align:start position:0% +assumption when we looked at um option A + + + align:start position:0% +assumption when we looked at um option A +so it's still good for option B um and + + align:start position:0% +so it's still good for option B um and + + + align:start position:0% +so it's still good for option B um and +we can use the Henderson Hustelbach. + + align:start position:0% +we can use the Henderson Hustelbach. + + + align:start position:0% +we can use the Henderson Hustelbach. +Now, if it was greater than 5%, then you + + align:start position:0% +Now, if it was greater than 5%, then you + + + align:start position:0% +Now, if it was greater than 5%, then you +can only use option one and you must use + + align:start position:0% +can only use option one and you must use + + + align:start position:0% +can only use option one and you must use +the quadratic equation. But this doesn't + + align:start position:0% +the quadratic equation. But this doesn't + + + align:start position:0% +the quadratic equation. But this doesn't +happen very often because a buffer is + + align:start position:0% +happen very often because a buffer is + + + align:start position:0% +happen very often because a buffer is +usually not a very good buffer if X is + + align:start position:0% +usually not a very good buffer if X is + + + align:start position:0% +usually not a very good buffer if X is +not small. A buffer is a good buffer + + align:start position:0% +not small. A buffer is a good buffer + + + align:start position:0% +not small. A buffer is a good buffer +when you have a weak conjugate acid + + align:start position:0% +when you have a weak conjugate acid + + + align:start position:0% +when you have a weak conjugate acid +pair. And when you have weak conjugate + + align:start position:0% +pair. And when you have weak conjugate + + + align:start position:0% +pair. And when you have weak conjugate +acids and bases, then usually X is + + align:start position:0% +acids and bases, then usually X is + + + align:start position:0% +acids and bases, then usually X is +small. It doesn't ionize much in water. + + align:start position:0% +small. It doesn't ionize much in water. + + + align:start position:0% +small. It doesn't ionize much in water. +So most of the time these assumptions + + align:start position:0% +So most of the time these assumptions + + + align:start position:0% +So most of the time these assumptions +hold. But if you're asked to check an + + align:start position:0% +hold. But if you're asked to check an + + + align:start position:0% +hold. But if you're asked to check an +assumption, that's what you need to do. + + align:start position:0% +assumption, that's what you need to do. + + + align:start position:0% +assumption, that's what you need to do. +All right. So we have point B two ways + + align:start position:0% +All right. So we have point B two ways + + + align:start position:0% +All right. So we have point B two ways +and we got the same answer. It's 3.38 + + align:start position:0% +and we got the same answer. It's 3.38 + + + align:start position:0% +and we got the same answer. It's 3.38 +and that's point B and we're in the + + align:start position:0% +and that's point B and we're in the + + + align:start position:0% +and that's point B and we're in the +buffering region there. What about point + + align:start position:0% +buffering region there. What about point + + + align:start position:0% +buffering region there. What about point +C? Point C is the half equivalence + + align:start position:0% +C? Point C is the half equivalence + + + align:start position:0% +C? Point C is the half equivalence +point. So let's think about what the pH + + align:start position:0% +point. So let's think about what the pH + + + align:start position:0% +point. So let's think about what the pH +would be at the half equivalence point. + + align:start position:0% +would be at the half equivalence point. + + + align:start position:0% +would be at the half equivalence point. +So at the half equivalence point, by + + align:start position:0% +So at the half equivalence point, by + + + align:start position:0% +So at the half equivalence point, by +definition, you've added half the number + + align:start position:0% +definition, you've added half the number + + + align:start position:0% +definition, you've added half the number +of moles you need to reach the + + align:start position:0% +of moles you need to reach the + + + align:start position:0% +of moles you need to reach the +equivalence point or half the volume of + + align:start position:0% +equivalence point or half the volume of + + + align:start position:0% +equivalence point or half the volume of +the strong base that you need to reach + + align:start position:0% +the strong base that you need to reach + + + align:start position:0% +the strong base that you need to reach +the equivalence point. And at this + + align:start position:0% +the equivalence point. And at this + + + align:start position:0% +the equivalence point. And at this +point, the number of moles of your weak + + align:start position:0% +point, the number of moles of your weak + + + align:start position:0% +point, the number of moles of your weak +acid equal the number of moles of your + + align:start position:0% +acid equal the number of moles of your + + + align:start position:0% +acid equal the number of moles of your +conjugate base. So when that is true and + + align:start position:0% +conjugate base. So when that is true and + + + align:start position:0% +conjugate base. So when that is true and +we look at the Henderson Hustelbach + + align:start position:0% +we look at the Henderson Hustelbach + + + align:start position:0% +we look at the Henderson Hustelbach +expression, we see that this term + + align:start position:0% +expression, we see that this term + + + align:start position:0% +expression, we see that this term +becomes one. + + align:start position:0% +becomes one. + + + align:start position:0% +becomes one. +And so therefore, pH equals + + align:start position:0% +And so therefore, pH equals + + + align:start position:0% +And so therefore, pH equals +pKa. So if you weren't given the pKa and + + align:start position:0% +pKa. So if you weren't given the pKa and + + + align:start position:0% +pKa. So if you weren't given the pKa and +you were just given the Ka, that's no + + align:start position:0% +you were just given the Ka, that's no + + + align:start position:0% +you were just given the Ka, that's no +problem because you can uh calculate it + + align:start position:0% +problem because you can uh calculate it + + + align:start position:0% +problem because you can uh calculate it +minus log of + + align:start position:0% +minus log of + + + align:start position:0% +minus log of +Ka. And so that's minus log of 1.77* + + align:start position:0% +Ka. And so that's minus log of 1.77* + + + align:start position:0% +Ka. And so that's minus log of 1.77* +10us4 for this problem, which gives us a + + align:start position:0% +10us4 for this problem, which gives us a + + + align:start position:0% +10us4 for this problem, which gives us a +pH of about 3.75. + + align:start position:0% + + + + align:start position:0% + +So, if you were just given the pKa, + + align:start position:0% +So, if you were just given the pKa, + + + align:start position:0% +So, if you were just given the pKa, +which is for this 3.75, + + align:start position:0% +which is for this 3.75, + + + align:start position:0% +which is for this 3.75, +um, and it's really not much more + + align:start position:0% +um, and it's really not much more + + + align:start position:0% +um, and it's really not much more +significant than that, honestly. And + + align:start position:0% +significant than that, honestly. And + + + align:start position:0% +significant than that, honestly. And +there actually not a lot of significant + + align:start position:0% +there actually not a lot of significant + + + align:start position:0% +there actually not a lot of significant +figures when it comes to measuring pH, + + align:start position:0% +figures when it comes to measuring pH, + + + align:start position:0% +figures when it comes to measuring pH, +um, or pKa's. Um, if on a test you're + + align:start position:0% +um, or pKa's. Um, if on a test you're + + + align:start position:0% +um, or pKa's. Um, if on a test you're +said, the pKa of this is 3.75. What is + + align:start position:0% +said, the pKa of this is 3.75. What is + + + align:start position:0% +said, the pKa of this is 3.75. What is +the pH at the half equivalence point? + + align:start position:0% +the pH at the half equivalence point? + + + align:start position:0% +the pH at the half equivalence point? +You could write down 3.75 and nothing + + align:start position:0% +You could write down 3.75 and nothing + + + align:start position:0% +You could write down 3.75 and nothing +else. You do not need to prove to me + + align:start position:0% +else. You do not need to prove to me + + + align:start position:0% +else. You do not need to prove to me +that that that this expression here is + + align:start position:0% +that that that this expression here is + + + align:start position:0% +that that that this expression here is +true at the half equivalence point. It's + + align:start position:0% +true at the half equivalence point. It's + + + align:start position:0% +true at the half equivalence point. It's +just a a way to ask a question that + + align:start position:0% +just a a way to ask a question that + + + align:start position:0% +just a a way to ask a question that +tests your knowledge of titrations. So, + + align:start position:0% +tests your knowledge of titrations. So, + + + align:start position:0% +tests your knowledge of titrations. So, +this is a good problem that involves + + align:start position:0% +this is a good problem that involves + + + align:start position:0% +this is a good problem that involves +very little work. So, you should be + + align:start position:0% +very little work. So, you should be + + + align:start position:0% +very little work. So, you should be +extremely excited if I'm asking you + + align:start position:0% +extremely excited if I'm asking you + + + align:start position:0% +extremely excited if I'm asking you +about the pH at a half equivalence point + + align:start position:0% +about the pH at a half equivalence point + + + align:start position:0% +about the pH at a half equivalence point +because that's going to be a real easy + + align:start position:0% +because that's going to be a real easy + + + align:start position:0% +because that's going to be a real easy +problem. Don't spend a lot of time on + + align:start position:0% +problem. Don't spend a lot of time on + + + align:start position:0% +problem. Don't spend a lot of time on +it. All right. So, we got point C + + align:start position:0% +it. All right. So, we got point C + + + align:start position:0% +it. All right. So, we got point C +3.75. Very close. We're sort of in this + + align:start position:0% +3.75. Very close. We're sort of in this + + + align:start position:0% +3.75. Very close. We're sort of in this +uh region where the pH is changing not + + align:start position:0% +uh region where the pH is changing not + + + align:start position:0% +uh region where the pH is changing not +that much. All right, so that's the end + + align:start position:0% +that much. All right, so that's the end + + + align:start position:0% +that much. All right, so that's the end +of that lecture, but the beginning of + + align:start position:0% +of that lecture, but the beginning of + + + align:start position:0% +of that lecture, but the beginning of +the next one starts where we left off. + + align:start position:0% +the next one starts where we left off. + + + align:start position:0% +the next one starts where we left off. +As I said, acid base titration problems + + align:start position:0% +As I said, acid base titration problems + + + align:start position:0% +As I said, acid base titration problems +take a long time. They're in two + + align:start position:0% +take a long time. They're in two + + + align:start position:0% +take a long time. They're in two +handouts. Um, and we're just going to + + align:start position:0% +handouts. Um, and we're just going to + + + align:start position:0% +handouts. Um, and we're just going to +kind of continue now um with the next + + align:start position:0% +kind of continue now um with the next + + + align:start position:0% +kind of continue now um with the next +handout and point S, the equivalence + + align:start position:0% +handout and point S, the equivalence + + + align:start position:0% +handout and point S, the equivalence +point. \ No newline at end of file diff --git a/pJdUR2uak2s.txt b/pJdUR2uak2s.txt new file mode 100644 index 0000000000000000000000000000000000000000..b90a26ea9cc18d45e6395eb8ad34c80deaae44b7 --- /dev/null +++ b/pJdUR2uak2s.txt @@ -0,0 +1,9115 @@ +align:start position:0% + +The following content is provided under + + align:start position:0% +The following content is provided under + + + align:start position:0% +The following content is provided under +a Creative Common License. Your support + + align:start position:0% +a Creative Common License. Your support + + + align:start position:0% +a Creative Common License. Your support +will help MIT Open Courseware continue + + align:start position:0% +will help MIT Open Courseware continue + + + align:start position:0% +will help MIT Open Courseware continue +to offer highquality educational + + align:start position:0% +to offer highquality educational + + + align:start position:0% +to offer highquality educational +resources for free. To make a donation + + align:start position:0% +resources for free. To make a donation + + + align:start position:0% +resources for free. To make a donation +or to view additional materials from + + align:start position:0% +or to view additional materials from + + + align:start position:0% +or to view additional materials from +hundreds of MIT courses, visit MIT Open + + align:start position:0% +hundreds of MIT courses, visit MIT Open + + + align:start position:0% +hundreds of MIT courses, visit MIT Open +Courseware at ocw.mmit.edu. + + align:start position:0% + + + + align:start position:0% + +Come + + align:start position:0% + + + + align:start position:0% + +on. Come on. + + align:start position:0% + + + + align:start position:0% + +Okay. So we have uh you can show the + + align:start position:0% +Okay. So we have uh you can show the + + + align:start position:0% +Okay. So we have uh you can show the +answer + + align:start position:0% +answer + + + align:start position:0% +answer +uh 57% one and three. So this is where + + align:start position:0% +uh 57% one and three. So this is where + + + align:start position:0% +uh 57% one and three. So this is where +we were at the end of last lecture. So + + align:start position:0% +we were at the end of last lecture. So + + + align:start position:0% +we were at the end of last lecture. So +if you didn't get this uh written down + + align:start position:0% +if you didn't get this uh written down + + + align:start position:0% +if you didn't get this uh written down +uh in your notes um you want to uh look + + align:start position:0% +uh in your notes um you want to uh look + + + align:start position:0% +uh in your notes um you want to uh look +at these + + align:start position:0% + + + + align:start position:0% + +definitions. So here in this we have NH3 + + align:start position:0% +definitions. So here in this we have NH3 + + + align:start position:0% +definitions. So here in this we have NH3 +with its lone pair and it is acting as + + align:start position:0% +with its lone pair and it is acting as + + + align:start position:0% +with its lone pair and it is acting as +uh the Lewis base and BF3 is acting as + + align:start position:0% +uh the Lewis base and BF3 is acting as + + + align:start position:0% +uh the Lewis base and BF3 is acting as +the Lewis acid. So a Louisis base + + align:start position:0% +the Lewis acid. So a Louisis base + + + align:start position:0% +the Lewis acid. So a Louisis base +donates its lone pair electrons and the + + align:start position:0% +donates its lone pair electrons and the + + + align:start position:0% +donates its lone pair electrons and the +acid accepts them. So what was the other + + align:start position:0% +acid accepts them. So what was the other + + + align:start position:0% +acid accepts them. So what was the other +definition that we had the Bronstead + + align:start position:0% +definition that we had the Bronstead + + + align:start position:0% +definition that we had the Bronstead +Lowry? Does someone want to tell me um + + align:start position:0% +Lowry? Does someone want to tell me um + + + align:start position:0% +Lowry? Does someone want to tell me um +what that definition was? + + align:start position:0% +what that definition was? + + + align:start position:0% +what that definition was? +Let's can you uh if we have a volunteer + + align:start position:0% +Let's can you uh if we have a volunteer + + + align:start position:0% +Let's can you uh if we have a volunteer +tell us the Bronstead Lowry definition. + + align:start position:0% + + + + align:start position:0% + +Pull out your notes. Okay. + + align:start position:0% + + + + align:start position:0% + +somehat. There you go. + + align:start position:0% + + + + align:start position:0% + +So, a Bronstet Lowry uh I'm not sure + + align:start position:0% +So, a Bronstet Lowry uh I'm not sure + + + align:start position:0% +So, a Bronstet Lowry uh I'm not sure +it's on. + + align:start position:0% +it's on. + + + align:start position:0% +it's on. +It is on. Okay. Bronstad Lowry base is + + align:start position:0% +It is on. Okay. Bronstad Lowry base is + + + align:start position:0% +It is on. Okay. Bronstad Lowry base is +something that accepts H+ or H30O plus. + + align:start position:0% +something that accepts H+ or H30O plus. + + + align:start position:0% +something that accepts H+ or H30O plus. +Yeah. So the base um accepts the + + align:start position:0% +Yeah. So the base um accepts the + + + align:start position:0% +Yeah. So the base um accepts the +hydrogen ion or the proton and the acid + + align:start position:0% +hydrogen ion or the proton and the acid + + + align:start position:0% +hydrogen ion or the proton and the acid +donates. So is this definition now + + align:start position:0% +donates. So is this definition now + + + align:start position:0% +donates. So is this definition now +incompatible? Are they completely + + align:start position:0% +incompatible? Are they completely + + + align:start position:0% +incompatible? Are they completely +opposite or could they be sort of uh + + align:start position:0% +opposite or could they be sort of uh + + + align:start position:0% +opposite or could they be sort of uh +work together? Does anyone have an + + align:start position:0% +work together? Does anyone have an + + + align:start position:0% +work together? Does anyone have an +opinion on + + align:start position:0% + + + + align:start position:0% + +that? So how many people think that + + align:start position:0% +that? So how many people think that + + + align:start position:0% +that? So how many people think that +these could be consistent definitions in + + align:start position:0% +these could be consistent definitions in + + + align:start position:0% +these could be consistent definitions in +some way? Okay. Oh, quite a few people + + align:start position:0% +some way? Okay. Oh, quite a few people + + + align:start position:0% +some way? Okay. Oh, quite a few people +um that that uh one could make that + + align:start position:0% +um that that uh one could make that + + + align:start position:0% +um that that uh one could make that +argument. So, if you know now that you + + align:start position:0% +argument. So, if you know now that you + + + align:start position:0% +argument. So, if you know now that you +can make the argument, does someone want + + align:start position:0% +can make the argument, does someone want + + + align:start position:0% +can make the argument, does someone want +to try to make + + align:start position:0% + + + + align:start position:0% + +it? We have a + + align:start position:0% +it? We have a + + + align:start position:0% +it? We have a +bag. All right. Um our mic went away, + + align:start position:0% +bag. All right. Um our mic went away, + + + align:start position:0% +bag. All right. Um our mic went away, +but uh can we get up get up over + + align:start position:0% +but uh can we get up get up over + + + align:start position:0% +but uh can we get up get up over +there? + + align:start position:0% +there? + + + align:start position:0% +there? +So, where did our mic runner go? I + + align:start position:0% +So, where did our mic runner go? I + + + align:start position:0% +So, where did our mic runner go? I +should have explained they were needed + + align:start position:0% +should have explained they were needed + + + align:start position:0% +should have explained they were needed +twice. All + + align:start position:0% + + + + align:start position:0% + +right. All right. Who uh said try this? + + align:start position:0% + + + + align:start position:0% + +How far? How far? + + align:start position:0% +How far? How far? + + + align:start position:0% +How far? How far? +How far? Uh all Bronstead Lowry bases + + align:start position:0% +How far? Uh all Bronstead Lowry bases + + + align:start position:0% +How far? Uh all Bronstead Lowry bases +are Lewis bases, but not all Lewis bases + + align:start position:0% +are Lewis bases, but not all Lewis bases + + + align:start position:0% +are Lewis bases, but not all Lewis bases +are Bronstead Lowry bases because um you + + align:start position:0% +are Bronstead Lowry bases because um you + + + align:start position:0% +are Bronstead Lowry bases because um you +can like act as a proxy with no hydrogen + + align:start position:0% +can like act as a proxy with no hydrogen + + + align:start position:0% +can like act as a proxy with no hydrogen +ion if it connects directly. But like if + + align:start position:0% +ion if it connects directly. But like if + + + align:start position:0% +ion if it connects directly. But like if +a hydrogen ion bonds an example H30 to + + align:start position:0% +a hydrogen ion bonds an example H30 to + + + align:start position:0% +a hydrogen ion bonds an example H30 to +the lone pair of an oxygen, then it's + + align:start position:0% +the lone pair of an oxygen, then it's + + + align:start position:0% +the lone pair of an oxygen, then it's +the same thing as a Louis base. + + align:start position:0% +the same thing as a Louis base. + + + align:start position:0% +the same thing as a Louis base. +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +Okay. So, so that's right. The the Lewis + + align:start position:0% +Okay. So, so that's right. The the Lewis + + + align:start position:0% +Okay. So, so that's right. The the Lewis +acid Lewis base definition works um if + + align:start position:0% +acid Lewis base definition works um if + + + align:start position:0% +acid Lewis base definition works um if +you don't have a hydrogen ion involved + + align:start position:0% +you don't have a hydrogen ion involved + + + align:start position:0% +you don't have a hydrogen ion involved +or a proton involved, but the other + + align:start position:0% +or a proton involved, but the other + + + align:start position:0% +or a proton involved, but the other +still still applies. So, remember that + + align:start position:0% +still still applies. So, remember that + + + align:start position:0% +still still applies. So, remember that +when you're accepting + + align:start position:0% +when you're accepting + + + align:start position:0% +when you're accepting +H+, you're taking it without an + + align:start position:0% +H+, you're taking it without an + + + align:start position:0% +H+, you're taking it without an +electron. So, the base is taking H+. So, + + align:start position:0% +electron. So, the base is taking H+. So, + + + align:start position:0% +electron. So, the base is taking H+. So, +it's donating its electrons to form the + + align:start position:0% +it's donating its electrons to form the + + + align:start position:0% +it's donating its electrons to form the +bond. And the acid when it gives up H+, + + align:start position:0% +bond. And the acid when it gives up H+, + + + align:start position:0% +bond. And the acid when it gives up H+, +it's keeping all of the electrons. It's + + align:start position:0% +it's keeping all of the electrons. It's + + + align:start position:0% +it's keeping all of the electrons. It's +accepting the electrons. So, when the + + align:start position:0% +accepting the electrons. So, when the + + + align:start position:0% +accepting the electrons. So, when the +acid gives up H+, it's accepting. And + + align:start position:0% +acid gives up H+, it's accepting. And + + + align:start position:0% +acid gives up H+, it's accepting. And +when the base takes H+, it's using its + + align:start position:0% +when the base takes H+, it's using its + + + align:start position:0% +when the base takes H+, it's using its +electrons. So, the um so the Lewis uh + + align:start position:0% +electrons. So, the um so the Lewis uh + + + align:start position:0% +electrons. So, the um so the Lewis uh +definitions are lone pair or electron + + align:start position:0% +definitions are lone pair or electron + + + align:start position:0% +definitions are lone pair or electron +centric definitions whereas Bronston + + align:start position:0% +centric definitions whereas Bronston + + + align:start position:0% +centric definitions whereas Bronston +Lowry is thinking about the proton. but + + align:start position:0% +Lowry is thinking about the proton. but + + + align:start position:0% +Lowry is thinking about the proton. but +they both kind of work together. So, + + align:start position:0% +they both kind of work together. So, + + + align:start position:0% +they both kind of work together. So, +that's a good review of of the + + align:start position:0% +that's a good review of of the + + + align:start position:0% +that's a good review of of the +definitions we talked about last time. + + align:start position:0% +definitions we talked about last time. + + + align:start position:0% +definitions we talked about last time. +And now I'll try to get my mic back + + align:start position:0% +And now I'll try to get my mic back + + + align:start position:0% +And now I'll try to get my mic back +on. All right. + + align:start position:0% +on. All right. + + + align:start position:0% +on. All right. +So, today we're going to continue + + align:start position:0% +So, today we're going to continue + + + align:start position:0% +So, today we're going to continue +talking about acid base and we're going + + align:start position:0% +talking about acid base and we're going + + + align:start position:0% +talking about acid base and we're going +to continue talking about acid base + + align:start position:0% +to continue talking about acid base + + + align:start position:0% +to continue talking about acid base +quite a bit. So, we have a couple we + + align:start position:0% +quite a bit. So, we have a couple we + + + align:start position:0% +quite a bit. So, we have a couple we +have a number more lectures on acid + + align:start position:0% +have a number more lectures on acid + + + align:start position:0% +have a number more lectures on acid +base. So, we're going to start today + + align:start position:0% +base. So, we're going to start today + + + align:start position:0% +base. So, we're going to start today +with the relationship between pKw, pH, + + align:start position:0% +with the relationship between pKw, pH, + + + align:start position:0% +with the relationship between pKw, pH, +and p. We're going to talk about the + + align:start position:0% +and p. We're going to talk about the + + + align:start position:0% +and p. We're going to talk about the +strengths of acids and bases and then + + align:start position:0% +strengths of acids and bases and then + + + align:start position:0% +strengths of acids and bases and then +we're going to start doing problems + + align:start position:0% +we're going to start doing problems + + + align:start position:0% +we're going to start doing problems +equilibrium acid base problems and we're + + align:start position:0% +equilibrium acid base problems and we're + + + align:start position:0% +equilibrium acid base problems and we're +going to do a bunch of those and + + align:start position:0% +going to do a bunch of those and + + + align:start position:0% +going to do a bunch of those and +students always uh who are doing this + + align:start position:0% +students always uh who are doing this + + + align:start position:0% +students always uh who are doing this +and learning it for the first time are + + align:start position:0% +and learning it for the first time are + + + align:start position:0% +and learning it for the first time are +telling me there is an infinite number + + align:start position:0% +telling me there is an infinite number + + + align:start position:0% +telling me there is an infinite number +of different kinds of problems. It's + + align:start position:0% +of different kinds of problems. It's + + + align:start position:0% +of different kinds of problems. It's +really not true. There are only five + + align:start position:0% +really not true. There are only five + + + align:start position:0% +really not true. There are only five +different types and today hopefully + + align:start position:0% +different types and today hopefully + + + align:start position:0% +different types and today hopefully +we'll get through two of them. So, first + + align:start position:0% +we'll get through two of them. So, first + + + align:start position:0% +we'll get through two of them. So, first +we need to think about water because + + align:start position:0% +we need to think about water because + + + align:start position:0% +we need to think about water because +water is a really important solvent when + + align:start position:0% +water is a really important solvent when + + + align:start position:0% +water is a really important solvent when +we're talking about acid base + + align:start position:0% +we're talking about acid base + + + align:start position:0% +we're talking about acid base +equilibrium. And we mentioned last time + + align:start position:0% +equilibrium. And we mentioned last time + + + align:start position:0% +equilibrium. And we mentioned last time +that water can act as an acid and a + + align:start position:0% +that water can act as an acid and a + + + align:start position:0% +that water can act as an acid and a +base. Does anyone remember what that's + + align:start position:0% +base. Does anyone remember what that's + + + align:start position:0% +base. Does anyone remember what that's +called? Something that can act as an + + align:start position:0% +called? Something that can act as an + + + align:start position:0% +called? Something that can act as an +acid and a + + align:start position:0% +acid and a + + + align:start position:0% +acid and a +base. Amphoteric. So here we have we can + + align:start position:0% +base. Amphoteric. So here we have we can + + + align:start position:0% +base. Amphoteric. So here we have we can +think about two waters going to um + + align:start position:0% +think about two waters going to um + + + align:start position:0% +think about two waters going to um +H3O+ and O. We could also write it out + + align:start position:0% +H3O+ and O. We could also write it out + + + align:start position:0% +H3O+ and O. We could also write it out +instead of just saying two waters. One + + align:start position:0% +instead of just saying two waters. One + + + align:start position:0% +instead of just saying two waters. One +water that's acting as the acid and + + align:start position:0% +water that's acting as the acid and + + + align:start position:0% +water that's acting as the acid and +another water is acting as a base. So + + align:start position:0% +another water is acting as a base. So + + + align:start position:0% +another water is acting as a base. So +the water that's acting as an acid gives + + align:start position:0% +the water that's acting as an acid gives + + + align:start position:0% +the water that's acting as an acid gives +up its hydrogen ion or proton to the + + align:start position:0% +up its hydrogen ion or proton to the + + + align:start position:0% +up its hydrogen ion or proton to the +base. The base accepts it forming a + + align:start position:0% +base. The base accepts it forming a + + + align:start position:0% +base. The base accepts it forming a +conjugate acid. And this water that lost + + align:start position:0% +conjugate acid. And this water that lost + + + align:start position:0% +conjugate acid. And this water that lost +H+ becomes O minus. So water plus water + + align:start position:0% +H+ becomes O minus. So water plus water + + + align:start position:0% +H+ becomes O minus. So water plus water +H2O plus H2O forms an acid and a base. + + align:start position:0% +H2O plus H2O forms an acid and a base. + + + align:start position:0% +H2O plus H2O forms an acid and a base. +So we can ask the question then how much + + align:start position:0% +So we can ask the question then how much + + + align:start position:0% +So we can ask the question then how much +water is in a glass of water or how much + + align:start position:0% +water is in a glass of water or how much + + + align:start position:0% +water is in a glass of water or how much +H2O is actually in this uh water uh + + align:start position:0% +H2O is actually in this uh water uh + + + align:start position:0% +H2O is actually in this uh water uh +container that I have here. So when I'm + + align:start position:0% +container that I have here. So when I'm + + + align:start position:0% +container that I have here. So when I'm +asking that question how much H2O in a + + align:start position:0% +asking that question how much H2O in a + + + align:start position:0% +asking that question how much H2O in a +container of water I am and if I know + + align:start position:0% +container of water I am and if I know + + + align:start position:0% +container of water I am and if I know +the delta G KN of that process I'm + + align:start position:0% +the delta G KN of that process I'm + + + align:start position:0% +the delta G KN of that process I'm +asking about what is the relationship + + align:start position:0% +asking about what is the relationship + + + align:start position:0% +asking about what is the relationship +between our products here our ionized + + align:start position:0% +between our products here our ionized + + + align:start position:0% +between our products here our ionized +acid and our base over here the ionized + + align:start position:0% +acid and our base over here the ionized + + + align:start position:0% +acid and our base over here the ionized +products of water compared to water at + + align:start position:0% +products of water compared to water at + + + align:start position:0% +products of water compared to water at +equilibrium because this container the + + align:start position:0% +equilibrium because this container the + + + align:start position:0% +equilibrium because this container the +water is in equilibrium so if I'm asking + + align:start position:0% +water is in equilibrium so if I'm asking + + + align:start position:0% +water is in equilibrium so if I'm asking +about the ratio of products to reactants + + align:start position:0% +about the ratio of products to reactants + + + align:start position:0% +about the ratio of products to reactants +at equilibrium. What am I asking + + align:start position:0% +at equilibrium. What am I asking + + + align:start position:0% +at equilibrium. What am I asking +about? Just yell it out. I'm asking + + align:start position:0% +about? Just yell it out. I'm asking + + + align:start position:0% +about? Just yell it out. I'm asking +about the equilibrium constant. Exactly. + + align:start position:0% +about the equilibrium constant. Exactly. + + + align:start position:0% +about the equilibrium constant. Exactly. +I'm asking what is K? What is the + + align:start position:0% +I'm asking what is K? What is the + + + align:start position:0% +I'm asking what is K? What is the +equilibrium constant? So, let's just + + align:start position:0% +equilibrium constant? So, let's just + + + align:start position:0% +equilibrium constant? So, let's just +briefly review the relationship. Um, + + align:start position:0% +briefly review the relationship. Um, + + + align:start position:0% +briefly review the relationship. Um, +we're given here a delta G KN and we're + + align:start position:0% +we're given here a delta G KN and we're + + + align:start position:0% +we're given here a delta G KN and we're +asking about K. What is the + + align:start position:0% +asking about K. What is the + + + align:start position:0% +asking about K. What is the +relationship? How do you calculate K if + + align:start position:0% +relationship? How do you calculate K if + + + align:start position:0% +relationship? How do you calculate K if +you know delta G KN? + + align:start position:0% +you know delta G KN? + + + align:start position:0% +you know delta G KN? +And we have some equations that will be + + align:start position:0% +And we have some equations that will be + + + align:start position:0% +And we have some equations that will be +given to you. Sorry, not quite yet. + + align:start position:0% +given to you. Sorry, not quite yet. + + + align:start position:0% +given to you. Sorry, not quite yet. +There's going to be a clicker question + + align:start position:0% +There's going to be a clicker question + + + align:start position:0% +There's going to be a clicker question +coming. Um, we have some equations here. + + align:start position:0% +coming. Um, we have some equations here. + + + align:start position:0% +coming. Um, we have some equations here. +So, we have delta G KN= minus RT natural + + align:start position:0% +So, we have delta G KN= minus RT natural + + + align:start position:0% +So, we have delta G KN= minus RT natural +log of K, which we can rearrange to + + align:start position:0% +log of K, which we can rearrange to + + + align:start position:0% +log of K, which we can rearrange to +solve for K. And let's just have a + + align:start position:0% +solve for K. And let's just have a + + + align:start position:0% +solve for K. And let's just have a +little reminder of what these terms are. + + align:start position:0% +little reminder of what these terms are. + + + align:start position:0% +little reminder of what these terms are. +So, we'll put this up here. T is + + align:start position:0% +So, we'll put this up here. T is + + + align:start position:0% +So, we'll put this up here. T is +temperature. And we're going to be + + align:start position:0% +temperature. And we're going to be + + + align:start position:0% +temperature. And we're going to be +talking about room temperature. This is + + align:start position:0% +talking about room temperature. This is + + + align:start position:0% +talking about room temperature. This is +at room temperature now. And in fact, + + align:start position:0% +at room temperature now. And in fact, + + + align:start position:0% +at room temperature now. And in fact, +almost all acidbased problems are going + + align:start position:0% +almost all acidbased problems are going + + + align:start position:0% +almost all acidbased problems are going +to be at room temperature. There might + + align:start position:0% +to be at room temperature. There might + + + align:start position:0% +to be at room temperature. There might +be a few differences, but we have a lot + + align:start position:0% +be a few differences, but we have a lot + + + align:start position:0% +be a few differences, but we have a lot +at room temperature. We have a constant + + align:start position:0% +at room temperature. We have a constant + + + align:start position:0% +at room temperature. We have a constant +R. And so three um 8.314 jewels per + + align:start position:0% +R. And so three um 8.314 jewels per + + + align:start position:0% +R. And so three um 8.314 jewels per +Kelvin per + + align:start position:0% +Kelvin per + + + align:start position:0% +Kelvin per +mole and delta G. So we were uh we were + + align:start position:0% +mole and delta G. So we were uh we were + + + align:start position:0% +mole and delta G. So we were uh we were +already told the value for delta G here. + + align:start position:0% +already told the value for delta G here. + + + align:start position:0% +already told the value for delta G here. +Now thinking about this room temperature + + align:start position:0% +Now thinking about this room temperature + + + align:start position:0% +Now thinking about this room temperature +this constant and this value for delta G + + align:start position:0% +this constant and this value for delta G + + + align:start position:0% +this constant and this value for delta G +do you expect a large or small value for + + align:start position:0% +do you expect a large or small value for + + + align:start position:0% +do you expect a large or small value for +K if you have this delta G KN value and + + align:start position:0% +K if you have this delta G KN value and + + + align:start position:0% +K if you have this delta G KN value and +that's our clicker question. + + align:start position:0% + + + + align:start position:0% + +All right, let's just do 10 more + + align:start position:0% +All right, let's just do 10 more + + + align:start position:0% +All right, let's just do 10 more +seconds. + + align:start position:0% + + + + align:start position:0% + +Yep. So K you would expect to be a small + + align:start position:0% +Yep. So K you would expect to be a small + + + align:start position:0% +Yep. So K you would expect to be a small +value less than one. And you could think + + align:start position:0% +value less than one. And you could think + + + align:start position:0% +value less than one. And you could think +about that mathematically from these + + align:start position:0% +about that mathematically from these + + + align:start position:0% +about that mathematically from these +expressions or you could think about it + + align:start position:0% +expressions or you could think about it + + + align:start position:0% +expressions or you could think about it +in terms of the value uh for delta G. So + + align:start position:0% +in terms of the value uh for delta G. So + + + align:start position:0% +in terms of the value uh for delta G. So +if we solve this and we put in our value + + align:start position:0% +if we solve this and we put in our value + + + align:start position:0% +if we solve this and we put in our value +for delta G KN which is a positive + + align:start position:0% +for delta G KN which is a positive + + + align:start position:0% +for delta G KN which is a positive +value. So the forward direction of the + + align:start position:0% +value. So the forward direction of the + + + align:start position:0% +value. So the forward direction of the +reaction is + + align:start position:0% +reaction is + + + align:start position:0% +reaction is +non-spontaneous. Um so we put in our + + align:start position:0% +non-spontaneous. Um so we put in our + + + align:start position:0% +non-spontaneous. Um so we put in our +positive delta G knot and our other + + align:start position:0% +positive delta G knot and our other + + + align:start position:0% +positive delta G knot and our other +values here. And this is again jewels + + align:start position:0% +values here. And this is again jewels + + + align:start position:0% +values here. And this is again jewels +per Kelvin per mole. Um and we have to + + align:start position:0% +per Kelvin per mole. Um and we have to + + + align:start position:0% +per Kelvin per mole. Um and we have to +make sure that we convert KJ to jewels + + align:start position:0% +make sure that we convert KJ to jewels + + + align:start position:0% +make sure that we convert KJ to jewels +and our units will cancel out. And if we + + align:start position:0% +and our units will cancel out. And if we + + + align:start position:0% +and our units will cancel out. And if we +do that, we get this value for natural + + align:start position:0% +do that, we get this value for natural + + + align:start position:0% +do that, we get this value for natural +log of K and this value for K of 1.0 * + + align:start position:0% +log of K and this value for K of 1.0 * + + + align:start position:0% +log of K and this value for K of 1.0 * +10 the minus14 at room temperature. And + + align:start position:0% +10 the minus14 at room temperature. And + + + align:start position:0% +10 the minus14 at room temperature. And +you will find that you end up memorizing + + align:start position:0% +you will find that you end up memorizing + + + align:start position:0% +you will find that you end up memorizing +this value if you do enough acidbased + + align:start position:0% +this value if you do enough acidbased + + + align:start position:0% +this value if you do enough acidbased +problems. In fact, you might have it + + align:start position:0% +problems. In fact, you might have it + + + align:start position:0% +problems. In fact, you might have it +memorized already. Okay, so this is in + + align:start position:0% +memorized already. Okay, so this is in + + + align:start position:0% +memorized already. Okay, so this is in +fact a small value and that indicates + + align:start position:0% +fact a small value and that indicates + + + align:start position:0% +fact a small value and that indicates +that only a small proportion of water + + align:start position:0% +that only a small proportion of water + + + align:start position:0% +that only a small proportion of water +molecules are ionized. about one + + align:start position:0% +molecules are ionized. about one + + + align:start position:0% +molecules are ionized. about one +molecule in every 200 million are + + align:start position:0% +molecule in every 200 million are + + + align:start position:0% +molecule in every 200 million are +ionized. So it's a very very small + + align:start position:0% +ionized. So it's a very very small + + + align:start position:0% +ionized. So it's a very very small +value. So there is a lot of H2O in a + + align:start position:0% +value. So there is a lot of H2O in a + + + align:start position:0% +value. So there is a lot of H2O in a +glass of water. So in here it's mostly + + align:start position:0% +glass of water. So in here it's mostly + + + align:start position:0% +glass of water. So in here it's mostly +H2O. Very few molecules are ionized in + + align:start position:0% +H2O. Very few molecules are ionized in + + + align:start position:0% +H2O. Very few molecules are ionized in +that. Now part of the reason why you're + + align:start position:0% +that. Now part of the reason why you're + + + align:start position:0% +that. Now part of the reason why you're +likely to have this value of K memorized + + align:start position:0% +likely to have this value of K memorized + + + align:start position:0% +likely to have this value of K memorized +is because it has a special name. This K + + align:start position:0% +is because it has a special name. This K + + + align:start position:0% +is because it has a special name. This K +is called KW for + + align:start position:0% +is called KW for + + + align:start position:0% +is called KW for +water. So that's easy to remember. And + + align:start position:0% +water. So that's easy to remember. And + + + align:start position:0% +water. So that's easy to remember. And +KW the equilibrium constant for water is + + align:start position:0% +KW the equilibrium constant for water is + + + align:start position:0% +KW the equilibrium constant for water is +equal to the hydrronium ion + + align:start position:0% +equal to the hydrronium ion + + + align:start position:0% +equal to the hydrronium ion +concentration times the hydroxide ion + + align:start position:0% +concentration times the hydroxide ion + + + align:start position:0% +concentration times the hydroxide ion +concentration. And since this is an + + align:start position:0% +concentration. And since this is an + + + align:start position:0% +concentration. And since this is an +equilibrium constant, if you're at + + align:start position:0% +equilibrium constant, if you're at + + + align:start position:0% +equilibrium constant, if you're at +constant temperature at room + + align:start position:0% +constant temperature at room + + + align:start position:0% +constant temperature at room +temperature, this will always equal 1.0. + + align:start position:0% +temperature, this will always equal 1.0. + + + align:start position:0% +temperature, this will always equal 1.0. +0 * 10 -14. This product is always going + + align:start position:0% +0 * 10 -14. This product is always going + + + align:start position:0% +0 * 10 -14. This product is always going +to be this at room temperature. And that + + align:start position:0% +to be this at room temperature. And that + + + align:start position:0% +to be this at room temperature. And that +is why it's going to turn out to be + + align:start position:0% +is why it's going to turn out to be + + + align:start position:0% +is why it's going to turn out to be +important because you're going to use + + align:start position:0% +important because you're going to use + + + align:start position:0% +important because you're going to use +that information in solving a lot of + + align:start position:0% +that information in solving a lot of + + + align:start position:0% +that information in solving a lot of +problems. All right. So if this is an + + align:start position:0% +problems. All right. So if this is an + + + align:start position:0% +problems. All right. So if this is an +equilibrium constant, um we want to + + align:start position:0% +equilibrium constant, um we want to + + + align:start position:0% +equilibrium constant, um we want to +think again about expressions for + + align:start position:0% +think again about expressions for + + + align:start position:0% +think again about expressions for +equilibrium. And just make a note that + + align:start position:0% +equilibrium. And just make a note that + + + align:start position:0% +equilibrium. And just make a note that +we did not include water squared on the + + align:start position:0% +we did not include water squared on the + + + align:start position:0% +we did not include water squared on the +bottom of this expression. So, KW equals + + align:start position:0% +bottom of this expression. So, KW equals + + + align:start position:0% +bottom of this expression. So, KW equals +hydrronium ion concentration times + + align:start position:0% +hydrronium ion concentration times + + + align:start position:0% +hydrronium ion concentration times +hydroxide ion concentration. You don't + + align:start position:0% +hydroxide ion concentration. You don't + + + align:start position:0% +hydroxide ion concentration. You don't +put it over water. And the reason for + + align:start position:0% +put it over water. And the reason for + + + align:start position:0% +put it over water. And the reason for +this is because this is a pretty pure + + align:start position:0% +this is because this is a pretty pure + + + align:start position:0% +this is because this is a pretty pure +solvent and you don't include pure + + align:start position:0% +solvent and you don't include pure + + + align:start position:0% +solvent and you don't include pure +solvents um in your equilibrium + + align:start position:0% +solvents um in your equilibrium + + + align:start position:0% +solvents um in your equilibrium +expression. You also don't include + + align:start position:0% +expression. You also don't include + + + align:start position:0% +expression. You also don't include +solids. So, we talked about that when we + + align:start position:0% +solids. So, we talked about that when we + + + align:start position:0% +solids. So, we talked about that when we +were talking about solubility. So, you + + align:start position:0% +were talking about solubility. So, you + + + align:start position:0% +were talking about solubility. So, you +have to remember that um solvents like + + align:start position:0% +have to remember that um solvents like + + + align:start position:0% +have to remember that um solvents like +water is nearly pure. doesn't go in. + + align:start position:0% +water is nearly pure. doesn't go in. + + + align:start position:0% +water is nearly pure. doesn't go in. +Pure other liquids, pure other solids + + align:start position:0% +Pure other liquids, pure other solids + + + align:start position:0% +Pure other liquids, pure other solids +are not included in your equilibrium + + align:start position:0% +are not included in your equilibrium + + + align:start position:0% +are not included in your equilibrium +expression. All right, so we now know + + align:start position:0% +expression. All right, so we now know + + + align:start position:0% +expression. All right, so we now know +about water. We know about um KW. Let's + + align:start position:0% +about water. We know about um KW. Let's + + + align:start position:0% +about water. We know about um KW. Let's +do a few more definitions and then think + + align:start position:0% +do a few more definitions and then think + + + align:start position:0% +do a few more definitions and then think +about how all these terms are related to + + align:start position:0% +about how all these terms are related to + + + align:start position:0% +about how all these terms are related to +each other. So a definition that many + + align:start position:0% +each other. So a definition that many + + + align:start position:0% +each other. So a definition that many +people already know probably if you + + align:start position:0% +people already know probably if you + + + align:start position:0% +people already know probably if you +taken any kind of science before you're + + align:start position:0% +taken any kind of science before you're + + + align:start position:0% +taken any kind of science before you're +probably aware that pH equals minus log + + align:start position:0% +probably aware that pH equals minus log + + + align:start position:0% +probably aware that pH equals minus log +of the hydrronium ion concentration of + + align:start position:0% +of the hydrronium ion concentration of + + + align:start position:0% +of the hydrronium ion concentration of +H3+ if you don't know it it will be on + + align:start position:0% +H3+ if you don't know it it will be on + + + align:start position:0% +H3+ if you don't know it it will be on +your equation sheet so um it doesn't + + align:start position:0% +your equation sheet so um it doesn't + + + align:start position:0% +your equation sheet so um it doesn't +really matter but there it is and + + align:start position:0% +really matter but there it is and + + + align:start position:0% +really matter but there it is and +there's also + + align:start position:0% +there's also + + + align:start position:0% +there's also +P equals minus log of the hydroxide ion + + align:start position:0% +P equals minus log of the hydroxide ion + + + align:start position:0% +P equals minus log of the hydroxide ion +concentration O minus + + align:start position:0% +concentration O minus + + + align:start position:0% +concentration O minus +Now let's think about the relationships + + align:start position:0% +Now let's think about the relationships + + + align:start position:0% +Now let's think about the relationships +of pKw, pH, and + + align:start position:0% +of pKw, pH, and + + + align:start position:0% +of pKw, pH, and +p. So + + align:start position:0% + + + + align:start position:0% + +relationships. So I just told you and + + align:start position:0% +relationships. So I just told you and + + + align:start position:0% +relationships. So I just told you and +maybe you've already memorized that KW + + align:start position:0% +maybe you've already memorized that KW + + + align:start position:0% +maybe you've already memorized that KW +is going to be equal to the hydrronium + + align:start position:0% +is going to be equal to the hydrronium + + + align:start position:0% +is going to be equal to the hydrronium +ion concentration times the hydroxide + + align:start position:0% +ion concentration times the hydroxide + + + align:start position:0% +ion concentration times the hydroxide +ion concentration. And that's going to + + align:start position:0% +ion concentration. And that's going to + + + align:start position:0% +ion concentration. And that's going to +be equal to 1.0 * 10us14th at room + + align:start position:0% +be equal to 1.0 * 10us14th at room + + + align:start position:0% +be equal to 1.0 * 10us14th at room +temperature. So now if we take this + + align:start position:0% +temperature. So now if we take this + + + align:start position:0% +temperature. So now if we take this +expression and we take the log of all of + + align:start position:0% +expression and we take the log of all of + + + align:start position:0% +expression and we take the log of all of +these terms and multiply by a negative + + align:start position:0% +these terms and multiply by a negative + + + align:start position:0% +these terms and multiply by a negative +value then we will get this expression. + + align:start position:0% +value then we will get this expression. + + + align:start position:0% +value then we will get this expression. +So minus log of KW is P + + align:start position:0% +So minus log of KW is P + + + align:start position:0% +So minus log of KW is P +KW and minus log of the hydrronium ion + + align:start position:0% +KW and minus log of the hydrronium ion + + + align:start position:0% +KW and minus log of the hydrronium ion +concentration is what? + + align:start position:0% +concentration is what? + + + align:start position:0% +concentration is what? +PH minus log of the hydroxide ion + + align:start position:0% +PH minus log of the hydroxide ion + + + align:start position:0% +PH minus log of the hydroxide ion +concentration is what? + + align:start position:0% +concentration is what? + + + align:start position:0% +concentration is what? +P. So P KW equals PH + + + align:start position:0% +P. So P KW equals PH + + + + align:start position:0% +P. So P KW equals PH + +P. And that is equal to + + align:start position:0% +P. And that is equal to + + + align:start position:0% +P. And that is equal to +14.0 at room temperature. And this is a + + align:start position:0% +14.0 at room temperature. And this is a + + + align:start position:0% +14.0 at room temperature. And this is a +very useful expression. The fact that PH + + align:start position:0% +very useful expression. The fact that PH + + + align:start position:0% +very useful expression. The fact that PH +and P are equal to 14. If you know one + + align:start position:0% +and P are equal to 14. If you know one + + + align:start position:0% +and P are equal to 14. If you know one +of these, then you know the other one by + + align:start position:0% +of these, then you know the other one by + + + align:start position:0% +of these, then you know the other one by +doing a simple + + align:start position:0% +doing a simple + + + align:start position:0% +doing a simple +subtraction. So you will find yourself + + align:start position:0% +subtraction. So you will find yourself + + + align:start position:0% +subtraction. So you will find yourself +using this expression quite often in the + + align:start position:0% +using this expression quite often in the + + + align:start position:0% +using this expression quite often in the +problem sets. And so I'll say that one + + align:start position:0% +problem sets. And so I'll say that one + + + align:start position:0% +problem sets. And so I'll say that one +the problem set that's due on Friday has + + align:start position:0% +the problem set that's due on Friday has + + + align:start position:0% +the problem set that's due on Friday has +just a couple of acidbased problems at + + align:start position:0% +just a couple of acidbased problems at + + + align:start position:0% +just a couple of acidbased problems at +the end. The next problem set will be + + align:start position:0% +the end. The next problem set will be + + + align:start position:0% +the end. The next problem set will be +100% acidbased problems. So there's a + + align:start position:0% +100% acidbased problems. So there's a + + + align:start position:0% +100% acidbased problems. So there's a +lot lot to look forward to. + + align:start position:0% +lot lot to look forward to. + + + align:start position:0% +lot lot to look forward to. +Okay, so let's talk about the strengths + + align:start position:0% +Okay, so let's talk about the strengths + + + align:start position:0% +Okay, so let's talk about the strengths +of acids and + + align:start position:0% +of acids and + + + align:start position:0% +of acids and +bases. So if you have a pH of pure + + align:start position:0% +bases. So if you have a pH of pure + + + align:start position:0% +bases. So if you have a pH of pure +water, it should be equal to minus log * + + align:start position:0% +water, it should be equal to minus log * + + + align:start position:0% +water, it should be equal to minus log * +1 1.0 * 10us 7 or the pH equals 7 which + + align:start position:0% +1 1.0 * 10us 7 or the pH equals 7 which + + + align:start position:0% +1 1.0 * 10us 7 or the pH equals 7 which +is a neutral pH. So if we have a scale + + align:start position:0% +is a neutral pH. So if we have a scale + + + align:start position:0% +is a neutral pH. So if we have a scale +here, pH minus1 to + + align:start position:0% +here, pH minus1 to + + + align:start position:0% +here, pH minus1 to +pH14, 7 is a neutral value. + + align:start position:0% +pH14, 7 is a neutral value. + + + align:start position:0% +pH14, 7 is a neutral value. +If we're talking about things that are + + align:start position:0% +If we're talking about things that are + + + align:start position:0% +If we're talking about things that are +acidic, the pH of an acidic solution is + + align:start position:0% +acidic, the pH of an acidic solution is + + + align:start position:0% +acidic, the pH of an acidic solution is +less than seven. And so this is the + + align:start position:0% +less than seven. And so this is the + + + align:start position:0% +less than seven. And so this is the +acidic part over + + align:start position:0% +acidic part over + + + align:start position:0% +acidic part over +here. And the pH of a basic solution is + + align:start position:0% +here. And the pH of a basic solution is + + + align:start position:0% +here. And the pH of a basic solution is +greater than seven. So that is down in + + align:start position:0% +greater than seven. So that is down in + + + align:start position:0% +greater than seven. So that is down in +this + + align:start position:0% +this + + + align:start position:0% +this +part. The EPA defines waste as + + align:start position:0% +part. The EPA defines waste as + + + align:start position:0% +part. The EPA defines waste as +corrosive. + + align:start position:0% +corrosive. + + + align:start position:0% +corrosive. +If the pH is lower than three, so that + + align:start position:0% +If the pH is lower than three, so that + + + align:start position:0% +If the pH is lower than three, so that +would be corrosive or higher than + + align:start position:0% +would be corrosive or higher than + + + align:start position:0% +would be corrosive or higher than +12.5, also corrosive. So living + + align:start position:0% +12.5, also corrosive. So living + + + align:start position:0% +12.5, also corrosive. So living +creatures like to be more in the neutral + + align:start position:0% +creatures like to be more in the neutral + + + align:start position:0% +creatures like to be more in the neutral +range. When you get to things of very + + align:start position:0% +range. When you get to things of very + + + align:start position:0% +range. When you get to things of very +low pH or very um high pH, that is less + + align:start position:0% +low pH or very um high pH, that is less + + + align:start position:0% +low pH or very um high pH, that is less +good. So let's now check out a few phes. + + align:start position:0% +good. So let's now check out a few phes. + + + align:start position:0% +good. So let's now check out a few phes. +And I'd like to have uh five uh TAs come + + align:start position:0% +And I'd like to have uh five uh TAs come + + + align:start position:0% +And I'd like to have uh five uh TAs come +down to help me with this. And I'll just + + align:start position:0% +down to help me with this. And I'll just + + + align:start position:0% +down to help me with this. And I'll just +show you what we're going to do. So, + + align:start position:0% +show you what we're going to do. So, + + + align:start position:0% +show you what we're going to do. So, +we'll have some volunteers. We have pH + + align:start position:0% +we'll have some volunteers. We have pH + + + align:start position:0% +we'll have some volunteers. We have pH +paper. The pH paper has an indicator on. + + align:start position:0% +paper. The pH paper has an indicator on. + + + align:start position:0% +paper. The pH paper has an indicator on. +You put the paper in the solution and + + align:start position:0% +You put the paper in the solution and + + + align:start position:0% +You put the paper in the solution and +then try to see which thing matches + + align:start position:0% +then try to see which thing matches + + + align:start position:0% +then try to see which thing matches +best. So, this is a very quick and dirty + + align:start position:0% +best. So, this is a very quick and dirty + + + align:start position:0% +best. So, this is a very quick and dirty +way to estimate pH. There's pH m meters + + align:start position:0% +way to estimate pH. There's pH m meters + + + align:start position:0% +way to estimate pH. There's pH m meters +and indicator dyes that work better, but + + align:start position:0% +and indicator dyes that work better, but + + + align:start position:0% +and indicator dyes that work better, but +you'll you'll have five people measure + + align:start position:0% +you'll you'll have five people measure + + + align:start position:0% +you'll you'll have five people measure +five things. We have ammonia, a cleaner. + + align:start position:0% +five things. We have ammonia, a cleaner. + + + align:start position:0% +five things. We have ammonia, a cleaner. +We talked about the importance of + + align:start position:0% +We talked about the importance of + + + align:start position:0% +We talked about the importance of +cleaning bathrooms um last lecture. We + + align:start position:0% +cleaning bathrooms um last lecture. We + + + align:start position:0% +cleaning bathrooms um last lecture. We +have + + align:start position:0% +have + + + align:start position:0% +have +soda. We have vinegar, which is often + + align:start position:0% +soda. We have vinegar, which is often + + + align:start position:0% +soda. We have vinegar, which is often +used in salad dressings. Um before I + + align:start position:0% +used in salad dressings. Um before I + + + align:start position:0% +used in salad dressings. Um before I +came here, I just went to a random sink + + align:start position:0% +came here, I just went to a random sink + + + align:start position:0% +came here, I just went to a random sink +and got some MIT water um to measure. + + align:start position:0% +and got some MIT water um to measure. + + + align:start position:0% +and got some MIT water um to measure. +And then this this is special. This is a + + align:start position:0% +And then this this is special. This is a + + + align:start position:0% +And then this this is special. This is a +prescription + + align:start position:0% +prescription + + + align:start position:0% +prescription +medicine. So this is um a solution of of + + align:start position:0% +medicine. So this is um a solution of of + + + align:start position:0% +medicine. So this is um a solution of of +iron to sulfate and this is prescribed + + align:start position:0% +iron to sulfate and this is prescribed + + + align:start position:0% +iron to sulfate and this is prescribed +if you're iron have an iron deficiency + + align:start position:0% +if you're iron have an iron deficiency + + + align:start position:0% +if you're iron have an iron deficiency +and iron deficiency is pretty bad and a + + align:start position:0% +and iron deficiency is pretty bad and a + + + align:start position:0% +and iron deficiency is pretty bad and a +lot of kids have iron deficiencies. It's + + align:start position:0% +lot of kids have iron deficiencies. It's + + + align:start position:0% +lot of kids have iron deficiencies. It's +really common in infants. So my daughter + + align:start position:0% +really common in infants. So my daughter + + + align:start position:0% +really common in infants. So my daughter +had an iron deficiency and this was her + + align:start position:0% +had an iron deficiency and this was her + + + align:start position:0% +had an iron deficiency and this was her +medicine. In fact, this box is + + align:start position:0% +medicine. In fact, this box is + + + align:start position:0% +medicine. In fact, this box is +completely full of this medicine. So, + + align:start position:0% +completely full of this medicine. So, + + + align:start position:0% +completely full of this medicine. So, +um, kids cannot swallow pills very + + align:start position:0% +um, kids cannot swallow pills very + + + align:start position:0% +um, kids cannot swallow pills very +easily. How many of you actually cannot + + align:start position:0% +easily. How many of you actually cannot + + + align:start position:0% +easily. How many of you actually cannot +swallow a pill? A lot of adults are pill + + align:start position:0% +swallow a pill? A lot of adults are pill + + + align:start position:0% +swallow a pill? A lot of adults are pill +challenged. You might maybe how many are + + align:start position:0% +challenged. You might maybe how many are + + + align:start position:0% +challenged. You might maybe how many are +happy swallowing pills? Let's do a more + + align:start position:0% +happy swallowing pills? Let's do a more + + + align:start position:0% +happy swallowing pills? Let's do a more +positive thing. Okay. Um, so swallowing + + align:start position:0% +positive thing. Okay. Um, so swallowing + + + align:start position:0% +positive thing. Okay. Um, so swallowing +pills is not everyone's + + align:start position:0% +pills is not everyone's + + + align:start position:0% +pills is not everyone's +favorite. Um, when you're a kid, it's + + align:start position:0% +favorite. Um, when you're a kid, it's + + + align:start position:0% +favorite. Um, when you're a kid, it's +really impossible to tell someone to + + align:start position:0% +really impossible to tell someone to + + + align:start position:0% +really impossible to tell someone to +like put something in their throat and + + align:start position:0% +like put something in their throat and + + + align:start position:0% +like put something in their throat and +like go back and try to get it down. + + align:start position:0% +like go back and try to get it down. + + + align:start position:0% +like go back and try to get it down. +Like they choke, spit up. It's awful. + + align:start position:0% +Like they choke, spit up. It's awful. + + + align:start position:0% +Like they choke, spit up. It's awful. +So, kids have to take medicine in + + align:start position:0% +So, kids have to take medicine in + + + align:start position:0% +So, kids have to take medicine in +solution. So, this medicine is 300 mg in + + align:start position:0% +solution. So, this medicine is 300 mg in + + + align:start position:0% +solution. So, this medicine is 300 mg in +5 milliliters. It's very concentrated + + align:start position:0% +5 milliliters. It's very concentrated + + + align:start position:0% +5 milliliters. It's very concentrated +because my daughter had a pretty severe + + align:start position:0% +because my daughter had a pretty severe + + + align:start position:0% +because my daughter had a pretty severe +iron deficiency. So when she tried + + align:start position:0% +iron deficiency. So when she tried + + + align:start position:0% +iron deficiency. So when she tried +taking it and I tasted it, it was + + align:start position:0% +taking it and I tasted it, it was + + + align:start position:0% +taking it and I tasted it, it was +horrific beyond belief. And after she + + align:start position:0% +horrific beyond belief. And after she + + + align:start position:0% +horrific beyond belief. And after she +had taken it a couple times, she started + + align:start position:0% +had taken it a couple times, she started + + + align:start position:0% +had taken it a couple times, she started +to have sores on her tongue and in her + + align:start position:0% +to have sores on her tongue and in her + + + align:start position:0% +to have sores on her tongue and in her +mouth. And I, as a chemist, said, "Let's + + align:start position:0% +mouth. And I, as a chemist, said, "Let's + + + align:start position:0% +mouth. And I, as a chemist, said, "Let's +measure the pH." So you will measure the + + align:start position:0% +measure the pH." So you will measure the + + + align:start position:0% +measure the pH." So you will measure the +pH of this prescription medicine for a + + align:start position:0% +pH of this prescription medicine for a + + + align:start position:0% +pH of this prescription medicine for a +fouryear-old and tell me whether the EPA + + align:start position:0% +fouryear-old and tell me whether the EPA + + + align:start position:0% +fouryear-old and tell me whether the EPA +would approve it or not. Anyway, so here + + align:start position:0% +would approve it or not. Anyway, so here + + + align:start position:0% +would approve it or not. Anyway, so here +are the TAs and they're going to come + + align:start position:0% +are the TAs and they're going to come + + + align:start position:0% +are the TAs and they're going to come +around. raise your hand if you're + + align:start position:0% +around. raise your hand if you're + + + align:start position:0% +around. raise your hand if you're +willing to measure a pH. Um, TAS, just + + align:start position:0% +willing to measure a pH. Um, TAS, just + + + align:start position:0% +willing to measure a pH. Um, TAS, just +grab a solution. I should have had you + + align:start position:0% +grab a solution. I should have had you + + + align:start position:0% +grab a solution. I should have had you +pour it, but okay. We're doing it. Um, + + align:start position:0% +pour it, but okay. We're doing it. Um, + + + align:start position:0% +pour it, but okay. We're doing it. Um, +and we'll go around and we'll + + align:start position:0% + + + + align:start position:0% + +measure and I will tell me what you find + + align:start position:0% +measure and I will tell me what you find + + + align:start position:0% +measure and I will tell me what you find +and I'll write it on the board. + + align:start position:0% + + + + align:start position:0% + +I don't think so. You are. Okay. + + align:start position:0% + + + + align:start position:0% + +All right. So, we have pH + + align:start position:0% + + + + align:start position:0% + +All right. Do we have an answer? + + align:start position:0% + + + + align:start position:0% + +Did we get one + + align:start position:0% +Did we get one + + + align:start position:0% +Did we get one +for what? Do you have ammonia is 12? + + align:start position:0% + + + + align:start position:0% + +So almost corrosive but not quite. You + + align:start position:0% +So almost corrosive but not quite. You + + + align:start position:0% +So almost corrosive but not quite. You +can still have uh clean, but if you want + + align:start position:0% +can still have uh clean, but if you want + + + align:start position:0% +can still have uh clean, but if you want +an excuse not to clean, you're like, + + align:start position:0% +an excuse not to clean, you're like, + + + align:start position:0% +an excuse not to clean, you're like, +"Sorry, too close uh to uh too + + align:start position:0% +"Sorry, too close uh to uh too + + + align:start position:0% +"Sorry, too close uh to uh too +corrosive." Do we have another one? MIT + + align:start position:0% +corrosive." Do we have another one? MIT + + + align:start position:0% +corrosive." Do we have another one? MIT +water. + + align:start position:0% +water. + + + align:start position:0% +water. +MIT water is seven. + + align:start position:0% + + + + align:start position:0% + +Awesome. So often actually water that + + align:start position:0% +Awesome. So often actually water that + + + align:start position:0% +Awesome. So often actually water that +you get from a tap is not seven because + + align:start position:0% +you get from a tap is not seven because + + + align:start position:0% +you get from a tap is not seven because +often there are ions that are dissolved + + align:start position:0% +often there are ions that are dissolved + + + align:start position:0% +often there are ions that are dissolved +in it. So, but a little bit around + + align:start position:0% +in it. So, but a little bit around + + + align:start position:0% +in it. So, but a little bit around +seven. Uh, a little bit of ions never + + align:start position:0% +seven. Uh, a little bit of ions never + + + align:start position:0% +seven. Uh, a little bit of ions never +hurt anyone. We have lots of ions in our + + align:start position:0% +hurt anyone. We have lots of ions in our + + + align:start position:0% +hurt anyone. We have lots of ions in our +body. Soda and soda at three and a half. + + align:start position:0% + + + + align:start position:0% + +So soda is definitely getting into our + + align:start position:0% +So soda is definitely getting into our + + + align:start position:0% +So soda is definitely getting into our +corrosive range + + align:start position:0% +corrosive range + + + align:start position:0% +corrosive range +and we have vinegar at + + align:start position:0% + + + + align:start position:0% + +two and that is corrosive. People often + + align:start position:0% +two and that is corrosive. People often + + + align:start position:0% +two and that is corrosive. People often +use pure vinegar to clean out a coffee + + align:start position:0% +use pure vinegar to clean out a coffee + + + align:start position:0% +use pure vinegar to clean out a coffee +pot um because it is pretty corrosive. + + align:start position:0% +pot um because it is pretty corrosive. + + + align:start position:0% +pot um because it is pretty corrosive. +It really does a good job of cleaning + + align:start position:0% +It really does a good job of cleaning + + + align:start position:0% +It really does a good job of cleaning +it. Um when you're having it in salad + + align:start position:0% +it. Um when you're having it in salad + + + align:start position:0% +it. Um when you're having it in salad +dressing, you don't want to have it pure + + align:start position:0% +dressing, you don't want to have it pure + + + align:start position:0% +dressing, you don't want to have it pure +vinegar. that would not be good to + + align:start position:0% +vinegar. that would not be good to + + + align:start position:0% +vinegar. that would not be good to +drink. And what about medicine? The + + align:start position:0% +drink. And what about medicine? The + + + align:start position:0% +drink. And what about medicine? The +medicine is a pH of two. Two. Okay. So, + + align:start position:0% +medicine is a pH of two. Two. Okay. So, + + + align:start position:0% +medicine is a pH of two. Two. Okay. So, +we also have in the corrosive + + align:start position:0% +we also have in the corrosive + + + align:start position:0% +we also have in the corrosive +category, the medicine that my + + align:start position:0% +category, the medicine that my + + + align:start position:0% +category, the medicine that my +four-year-old daughter um was asked to + + align:start position:0% +four-year-old daughter um was asked to + + + align:start position:0% +four-year-old daughter um was asked to +take. + + align:start position:0% +take. + + + align:start position:0% +take. +So when she started getting these soores + + align:start position:0% +So when she started getting these soores + + + align:start position:0% +So when she started getting these soores +in her mouth from taking her medicine, I + + align:start position:0% +in her mouth from taking her medicine, I + + + align:start position:0% +in her mouth from taking her medicine, I +brought some pH paper home and measured + + align:start position:0% +brought some pH paper home and measured + + + align:start position:0% +brought some pH paper home and measured +the pH and discovered that what she was + + align:start position:0% +the pH and discovered that what she was + + + align:start position:0% +the pH and discovered that what she was +taking was corrosive. So um I went to + + align:start position:0% +taking was corrosive. So um I went to + + + align:start position:0% +taking was corrosive. So um I went to +the doctor and said, "Can you prescribe + + align:start position:0% +the doctor and said, "Can you prescribe + + + align:start position:0% +the doctor and said, "Can you prescribe +something different? This medicine is + + align:start position:0% +something different? This medicine is + + + align:start position:0% +something different? This medicine is +corrosive." And the doctor looked at me + + align:start position:0% +corrosive." And the doctor looked at me + + + align:start position:0% +corrosive." And the doctor looked at me +and it's like the pH the pH is like two + + align:start position:0% +and it's like the pH the pH is like two + + + align:start position:0% +and it's like the pH the pH is like two +or lower. Um, and she looked at me and + + align:start position:0% +or lower. Um, and she looked at me and + + + align:start position:0% +or lower. Um, and she looked at me and +she's like, "What do you mean + + align:start position:0% + + + + align:start position:0% + +pH?" This is why I spend many lectures + + align:start position:0% +pH?" This is why I spend many lectures + + + align:start position:0% +pH?" This is why I spend many lectures +on pH in this class and acids and bases. + + align:start position:0% +on pH in this class and acids and bases. + + + align:start position:0% +on pH in this class and acids and bases. +Some of you will be doctors and some of + + align:start position:0% +Some of you will be doctors and some of + + + align:start position:0% +Some of you will be doctors and some of +you will not encourage parents to buy + + align:start position:0% +you will not encourage parents to buy + + + align:start position:0% +you will not encourage parents to buy +this much corrosive thing to feed their + + align:start position:0% +this much corrosive thing to feed their + + + align:start position:0% +this much corrosive thing to feed their +child when they're iron deficient. So, + + align:start position:0% +child when they're iron deficient. So, + + + align:start position:0% +child when they're iron deficient. So, +this is what I'm talking about. And for + + align:start position:0% +this is what I'm talking about. And for + + + align:start position:0% +this is what I'm talking about. And for +those of you who are not going to be + + align:start position:0% +those of you who are not going to be + + + align:start position:0% +those of you who are not going to be +doctors, many of you will probably have + + align:start position:0% +doctors, many of you will probably have + + + align:start position:0% +doctors, many of you will probably have +children with an iron deficiency. It's + + align:start position:0% +children with an iron deficiency. It's + + + align:start position:0% +children with an iron deficiency. It's +super common. So you will know um that + + align:start position:0% +super common. So you will know um that + + + align:start position:0% +super common. So you will know um that +you need to measure the pH of the + + align:start position:0% +you need to measure the pH of the + + + align:start position:0% +you need to measure the pH of the +solution before giving it to your child. + + align:start position:0% +solution before giving it to your child. + + + align:start position:0% +solution before giving it to your child. +So what did I do? So what I did was I + + align:start position:0% +So what did I do? So what I did was I + + + align:start position:0% +So what did I do? So what I did was I +bought adult pills, same stuff, iron + + align:start position:0% +bought adult pills, same stuff, iron + + + align:start position:0% +bought adult pills, same stuff, iron +sulfate, and I got made sure that this + + align:start position:0% +sulfate, and I got made sure that this + + + align:start position:0% +sulfate, and I got made sure that this +told me the number of milligrams that + + align:start position:0% +told me the number of milligrams that + + + align:start position:0% +told me the number of milligrams that +were in there. I looked at what was + + align:start position:0% +were in there. I looked at what was + + + align:start position:0% +were in there. I looked at what was +prescribed. So, I got the pills with the + + align:start position:0% +prescribed. So, I got the pills with the + + + align:start position:0% +prescribed. So, I got the pills with the +correct number of milligrams and then I + + align:start position:0% +correct number of milligrams and then I + + + align:start position:0% +correct number of milligrams and then I +crushed them. And that stuff also tastes + + align:start position:0% +crushed them. And that stuff also tastes + + + align:start position:0% +crushed them. And that stuff also tastes +really nasty. But a little tip for the + + align:start position:0% +really nasty. But a little tip for the + + + align:start position:0% +really nasty. But a little tip for the +future, there's one and only one that I + + align:start position:0% +future, there's one and only one that I + + + align:start position:0% +future, there's one and only one that I +discovered taste that can cover the + + align:start position:0% +discovered taste that can cover the + + + align:start position:0% +discovered taste that can cover the +taste of iron 2 sulfate and that is + + align:start position:0% + + + + align:start position:0% + +Nutella. So, don't give your child + + align:start position:0% +Nutella. So, don't give your child + + + align:start position:0% +Nutella. So, don't give your child +corrosive medicine. Give them crushed + + align:start position:0% +corrosive medicine. Give them crushed + + + align:start position:0% +corrosive medicine. Give them crushed +pills in + + align:start position:0% +pills in + + + align:start position:0% +pills in +Nutella. PH is important. pH is + + align:start position:0% +Nutella. PH is important. pH is + + + align:start position:0% +Nutella. PH is important. pH is +important. + + align:start position:0% +important. + + + align:start position:0% +important. +Okay. So, let's talk about the strengths + + align:start position:0% +Okay. So, let's talk about the strengths + + + align:start position:0% +Okay. So, let's talk about the strengths +of + + align:start position:0% + + + + align:start position:0% + +acids. And you might want to reconsider + + align:start position:0% +acids. And you might want to reconsider + + + align:start position:0% +acids. And you might want to reconsider +huge soda consumption, too. I I I don't + + align:start position:0% +huge soda consumption, too. I I I don't + + + align:start position:0% +huge soda consumption, too. I I I don't +really know, but uh that's something you + + align:start position:0% +really know, but uh that's something you + + + align:start position:0% +really know, but uh that's something you +might want to think about. Okay. + + align:start position:0% +might want to think about. Okay. + + + align:start position:0% +might want to think about. Okay. +Strength of acids. + + align:start position:0% + + + + align:start position:0% + +So here we have some acetic + + align:start position:0% +So here we have some acetic + + + align:start position:0% +So here we have some acetic +acid CH3 CO aquous dissolved in our + + align:start position:0% +acid CH3 CO aquous dissolved in our + + + align:start position:0% +acid CH3 CO aquous dissolved in our +solvent which is liquid + + align:start position:0% +solvent which is liquid + + + align:start position:0% +solvent which is liquid +water and this is an acid so it will + + align:start position:0% +water and this is an acid so it will + + + align:start position:0% +water and this is an acid so it will +give up a hydrogen ion or a proton to + + align:start position:0% +give up a hydrogen ion or a proton to + + + align:start position:0% +give up a hydrogen ion or a proton to +the water which acts as a base and forms + + align:start position:0% +the water which acts as a base and forms + + + align:start position:0% +the water which acts as a base and forms +hydro forms our hydrronium ions H3O plus + + align:start position:0% +hydro forms our hydrronium ions H3O plus + + + align:start position:0% +hydro forms our hydrronium ions H3O plus +and also the conjugate base of the acid. + + align:start position:0% +and also the conjugate base of the acid. + + + align:start position:0% +and also the conjugate base of the acid. +So it's the acid missing H+. So C H3 C + + align:start position:0% +So it's the acid missing H+. So C H3 C + + + align:start position:0% +So it's the acid missing H+. So C H3 C +minus. So if we're talking about the + + align:start position:0% +minus. So if we're talking about the + + + align:start position:0% +minus. So if we're talking about the +strength of the acid, what we really + + align:start position:0% +strength of the acid, what we really + + + align:start position:0% +strength of the acid, what we really +want to know is how much of that acid + + align:start position:0% +want to know is how much of that acid + + + align:start position:0% +want to know is how much of that acid +forms ions, how much of it ionizes. That + + align:start position:0% +forms ions, how much of it ionizes. That + + + align:start position:0% +forms ions, how much of it ionizes. That +is going to make determine how strong it + + align:start position:0% +is going to make determine how strong it + + + align:start position:0% +is going to make determine how strong it +is because the amount that ionizes is + + align:start position:0% +is because the amount that ionizes is + + + align:start position:0% +is because the amount that ionizes is +equal to the amount of the hydrronium + + align:start position:0% +equal to the amount of the hydrronium + + + align:start position:0% +equal to the amount of the hydrronium +ions you get. and pH equals minus the + + align:start position:0% +ions you get. and pH equals minus the + + + align:start position:0% +ions you get. and pH equals minus the +concentration of hydrronium ions. So the + + align:start position:0% +concentration of hydrronium ions. So the + + + align:start position:0% +concentration of hydrronium ions. So the +pH depends on the extent to which it + + align:start position:0% +pH depends on the extent to which it + + + align:start position:0% +pH depends on the extent to which it +ionizes. And again we're talking about + + align:start position:0% +ionizes. And again we're talking about + + + align:start position:0% +ionizes. And again we're talking about +an at equilibrium. So we're talking + + align:start position:0% +an at equilibrium. So we're talking + + + align:start position:0% +an at equilibrium. So we're talking +about a equilibrium constant. And this + + align:start position:0% +about a equilibrium constant. And this + + + align:start position:0% +about a equilibrium constant. And this +one also gets a fancy name in acids and + + align:start position:0% +one also gets a fancy name in acids and + + + align:start position:0% +one also gets a fancy name in acids and +bases. All the equilibrium constants get + + align:start position:0% +bases. All the equilibrium constants get + + + align:start position:0% +bases. All the equilibrium constants get +their own little names. And this is the + + align:start position:0% +their own little names. And this is the + + + align:start position:0% +their own little names. And this is the +acid ionization constant Ka. So it's the + + align:start position:0% +acid ionization constant Ka. So it's the + + + align:start position:0% +acid ionization constant Ka. So it's the +equilibrium constant for an acid, K a. + + align:start position:0% +equilibrium constant for an acid, K a. + + + align:start position:0% +equilibrium constant for an acid, K a. +So that's at least very easy to + + align:start position:0% +So that's at least very easy to + + + align:start position:0% +So that's at least very easy to +remember. So now based on what you know + + align:start position:0% +remember. So now based on what you know + + + align:start position:0% +remember. So now based on what you know +about equilibrium constants, why don't + + align:start position:0% +about equilibrium constants, why don't + + + align:start position:0% +about equilibrium constants, why don't +you uh tell me the answer to this + + align:start position:0% + + + + align:start position:0% + +All right, 10 more seconds. + + align:start position:0% + + + + align:start position:0% + +All + + align:start position:0% +All + + + align:start position:0% +All +right. So, this one is wrong. It's + + align:start position:0% +right. So, this one is wrong. It's + + + align:start position:0% +right. So, this one is wrong. It's +always products over reactants for an + + align:start position:0% +always products over reactants for an + + + align:start position:0% +always products over reactants for an +equilibrium expression. Water is a + + align:start position:0% +equilibrium expression. Water is a + + + align:start position:0% +equilibrium expression. Water is a +solvent and is nearly pure, so it should + + align:start position:0% +solvent and is nearly pure, so it should + + + align:start position:0% +solvent and is nearly pure, so it should +not be there. This should be in the + + align:start position:0% +not be there. This should be in the + + + align:start position:0% +not be there. This should be in the +expression because it's aquous. If it + + align:start position:0% +expression because it's aquous. If it + + + align:start position:0% +expression because it's aquous. If it +were solid, it wouldn't be included, but + + align:start position:0% +were solid, it wouldn't be included, but + + + align:start position:0% +were solid, it wouldn't be included, but +it's aquous, so its concentration is + + align:start position:0% +it's aquous, so its concentration is + + + align:start position:0% +it's aquous, so its concentration is +going to change. So, it is in our + + align:start position:0% +going to change. So, it is in our + + + align:start position:0% +going to change. So, it is in our +expression. Um, see answer to three for + + align:start position:0% +expression. Um, see answer to three for + + + align:start position:0% +expression. Um, see answer to three for +that one. Uh, enough information and + + align:start position:0% +that one. Uh, enough information and + + + align:start position:0% +that one. Uh, enough information and +it's not correct. Okay. So, we can write + + align:start position:0% +it's not correct. Okay. So, we can write + + + align:start position:0% +it's not correct. Okay. So, we can write +the expression for Ka. So, that's equal + + align:start position:0% +the expression for Ka. So, that's equal + + + align:start position:0% +the expression for Ka. So, that's equal +to the products, our hydrononeium + + align:start position:0% +to the products, our hydrononeium + + + align:start position:0% +to the products, our hydrononeium +concentration, our conjugate base over + + align:start position:0% +concentration, our conjugate base over + + + align:start position:0% +concentration, our conjugate base over +our conjugate acid. + + align:start position:0% +our conjugate acid. + + + align:start position:0% +our conjugate acid. +And so we can look at what the value is + + align:start position:0% +And so we can look at what the value is + + + align:start position:0% +And so we can look at what the value is +for this expression and we can look it + + align:start position:0% +for this expression and we can look it + + + align:start position:0% +for this expression and we can look it +up. Um there's lots and lots of tables + + align:start position:0% +up. Um there's lots and lots of tables + + + align:start position:0% +up. Um there's lots and lots of tables +of these in your book and it is 1.76 + + align:start position:0% +of these in your book and it is 1.76 + + + align:start position:0% +of these in your book and it is 1.76 +* + + align:start position:0% +* + + + align:start position:0% +* +10us5 or minus3 I don't have my glasses. + + align:start position:0% +10us5 or minus3 I don't have my glasses. + + + align:start position:0% +10us5 or minus3 I don't have my glasses. +Um whatever it says there I think it's + + align:start position:0% +Um whatever it says there I think it's + + + align:start position:0% +Um whatever it says there I think it's +five. Um at room temperature which is + + align:start position:0% +five. Um at room temperature which is + + + align:start position:0% +five. Um at room temperature which is +small. + + align:start position:0% +small. + + + align:start position:0% +small. +So when a Ka is small, it means that + + align:start position:0% +So when a Ka is small, it means that + + + align:start position:0% +So when a Ka is small, it means that +very little of it is + + align:start position:0% +very little of it is + + + align:start position:0% +very little of it is +ionizing. And so only a small number of + + align:start position:0% +ionizing. And so only a small number of + + + align:start position:0% +ionizing. And so only a small number of +our acid molecules of our acetic acid + + align:start position:0% +our acid molecules of our acetic acid + + + align:start position:0% +our acid molecules of our acetic acid +molecules are donating their proton when + + align:start position:0% +molecules are donating their proton when + + + align:start position:0% +molecules are donating their proton when +they're dissolved in water. So that's + + align:start position:0% +they're dissolved in water. So that's + + + align:start position:0% +they're dissolved in water. So that's +the definition of a weak acid when it + + align:start position:0% +the definition of a weak acid when it + + + align:start position:0% +the definition of a weak acid when it +has a very small Ka. It's not ionizing + + align:start position:0% +has a very small Ka. It's not ionizing + + + align:start position:0% +has a very small Ka. It's not ionizing +very much. Now, in doing these units, a + + align:start position:0% +very much. Now, in doing these units, a + + + align:start position:0% +very much. Now, in doing these units, a +lot of people get hung up on kind of the + + align:start position:0% +lot of people get hung up on kind of the + + + align:start position:0% +lot of people get hung up on kind of the +names of the different acids. Um, and + + align:start position:0% +names of the different acids. Um, and + + + align:start position:0% +names of the different acids. Um, and +and one of the first steps in solving a + + align:start position:0% +and one of the first steps in solving a + + + align:start position:0% +and one of the first steps in solving a +problem is to write the equilibrium + + align:start position:0% +problem is to write the equilibrium + + + align:start position:0% +problem is to write the equilibrium +expression out, but people get hung up + + align:start position:0% +expression out, but people get hung up + + + align:start position:0% +expression out, but people get hung up +with that. So, don't get hung up with + + align:start position:0% +with that. So, don't get hung up with + + + align:start position:0% +with that. So, don't get hung up with +that. You can use generic expressions + + align:start position:0% +that. You can use generic expressions + + + align:start position:0% +that. You can use generic expressions +for acids and water. If you don't want + + align:start position:0% +for acids and water. If you don't want + + + align:start position:0% +for acids and water. If you don't want +to write out the whole name of the acid, + + align:start position:0% +to write out the whole name of the acid, + + + align:start position:0% +to write out the whole name of the acid, +you can always just say HA aquous plus + + align:start position:0% +you can always just say HA aquous plus + + + align:start position:0% +you can always just say HA aquous plus +the solvent water goes to hydrronium ion + + align:start position:0% +the solvent water goes to hydrronium ion + + + align:start position:0% +the solvent water goes to hydrronium ion +ions plus a minus, the conjugate of the + + align:start position:0% +ions plus a minus, the conjugate of the + + + align:start position:0% +ions plus a minus, the conjugate of the +weak acid. So this is an acid in water + + align:start position:0% +weak acid. So this is an acid in water + + + align:start position:0% +weak acid. So this is an acid in water +and the acid is HA here and an acid + + align:start position:0% +and the acid is HA here and an acid + + + align:start position:0% +and the acid is HA here and an acid +expression should be forming + + align:start position:0% +expression should be forming + + + align:start position:0% +expression should be forming +hydrononeium ions. If it's acidic, you + + align:start position:0% +hydrononeium ions. If it's acidic, you + + + align:start position:0% +hydrononeium ions. If it's acidic, you +should have acidic pH and so you need to + + align:start position:0% +should have acidic pH and so you need to + + + align:start position:0% +should have acidic pH and so you need to +have some H3+ around. You can also write + + align:start position:0% +have some H3+ around. You can also write + + + align:start position:0% +have some H3+ around. You can also write +this expression as + + align:start position:0% +this expression as + + + align:start position:0% +this expression as +BH+ plus water. BH+ can give up the H+ + + align:start position:0% +BH+ plus water. BH+ can give up the H+ + + + align:start position:0% +BH+ plus water. BH+ can give up the H+ +and become B and also generate + + align:start position:0% +and become B and also generate + + + align:start position:0% +and become B and also generate +hydrronium ions. So here the acid is + + align:start position:0% +hydrronium ions. So here the acid is + + + align:start position:0% +hydrronium ions. So here the acid is +BHA and often when you're looking at + + align:start position:0% +BHA and often when you're looking at + + + align:start position:0% +BHA and often when you're looking at +these kinds of uh problems a weak acid + + align:start position:0% +these kinds of uh problems a weak acid + + + align:start position:0% +these kinds of uh problems a weak acid +will be HA but sometimes you have a + + align:start position:0% +will be HA but sometimes you have a + + + align:start position:0% +will be HA but sometimes you have a +problem involving the conjugate acid of + + align:start position:0% +problem involving the conjugate acid of + + + align:start position:0% +problem involving the conjugate acid of +a weak base and that's often expressed + + align:start position:0% +a weak base and that's often expressed + + + align:start position:0% +a weak base and that's often expressed +as + + align:start position:0% +as + + + align:start position:0% +as +BH+. So both of these expressions are + + align:start position:0% +BH+. So both of these expressions are + + + align:start position:0% +BH+. So both of these expressions are +valid for an acid in + + align:start position:0% +valid for an acid in + + + align:start position:0% +valid for an acid in +water. So now let's think about strong + + align:start position:0% +water. So now let's think about strong + + + align:start position:0% +water. So now let's think about strong +acids versus weaker acids. And here's + + align:start position:0% +acids versus weaker acids. And here's + + + align:start position:0% +acids versus weaker acids. And here's +our definition in this class. A strong + + align:start position:0% +our definition in this class. A strong + + + align:start position:0% +our definition in this class. A strong +acid has a Ka greater than one. A lot of + + align:start position:0% +acid has a Ka greater than one. A lot of + + + align:start position:0% +acid has a Ka greater than one. A lot of +strong acids have a Ka really, really, + + align:start position:0% +strong acids have a Ka really, really, + + + align:start position:0% +strong acids have a Ka really, really, +really greater than one. And the acid + + align:start position:0% +really greater than one. And the acid + + + align:start position:0% +really greater than one. And the acid +ionizes almost completely. So if you say + + align:start position:0% +ionizes almost completely. So if you say + + + align:start position:0% +ionizes almost completely. So if you say +it's a strong acid in water, whatever + + align:start position:0% +it's a strong acid in water, whatever + + + align:start position:0% +it's a strong acid in water, whatever +concentration of a acid you put in is + + align:start position:0% +concentration of a acid you put in is + + + align:start position:0% +concentration of a acid you put in is +going to be equal to the concentration + + align:start position:0% +going to be equal to the concentration + + + align:start position:0% +going to be equal to the concentration +of hydrronium ions. It basically goes + + align:start position:0% +of hydrronium ions. It basically goes + + + align:start position:0% +of hydrronium ions. It basically goes +straight. You form lots and lots and + + align:start position:0% +straight. You form lots and lots and + + + align:start position:0% +straight. You form lots and lots and +lots of products at equilibrium. A weak + + align:start position:0% +lots of products at equilibrium. A weak + + + align:start position:0% +lots of products at equilibrium. A weak +acid has a Ka of less than one. And a + + align:start position:0% +acid has a Ka of less than one. And a + + + align:start position:0% +acid has a Ka of less than one. And a +weak acid does not form many ionized + + align:start position:0% +weak acid does not form many ionized + + + align:start position:0% +weak acid does not form many ionized +species in solution. Not very much + + align:start position:0% +species in solution. Not very much + + + align:start position:0% +species in solution. Not very much +H3+ is + + align:start position:0% +H3+ is + + + align:start position:0% +H3+ is +formed. + + align:start position:0% +formed. + + + align:start position:0% +formed. +Okay. So what about + + align:start position:0% +Okay. So what about + + + align:start position:0% +Okay. So what about +pKa? PKAs are really important in + + align:start position:0% +pKa? PKAs are really important in + + + align:start position:0% +pKa? PKAs are really important in +organic chemistry and biology in a lot + + align:start position:0% +organic chemistry and biology in a lot + + + align:start position:0% +organic chemistry and biology in a lot +of areas. And every year the organic + + align:start position:0% +of areas. And every year the organic + + + align:start position:0% +of areas. And every year the organic +chemistry faculty in + + align:start position:0% +chemistry faculty in + + + align:start position:0% +chemistry faculty in +512 talk about pKa's and organic and the + + align:start position:0% +512 talk about pKa's and organic and the + + + align:start position:0% +512 talk about pKa's and organic and the +students there say no we never learned + + align:start position:0% +students there say no we never learned + + + align:start position:0% +students there say no we never learned +about that. They're like you took + + align:start position:0% +about that. They're like you took + + + align:start position:0% +about that. They're like you took +freshman chem right it's like a GI or + + align:start position:0% +freshman chem right it's like a GI or + + + align:start position:0% +freshman chem right it's like a GI or +you passed the test you should know + + align:start position:0% +you passed the test you should know + + + align:start position:0% +you passed the test you should know +about PKAs. They're like no. So they + + align:start position:0% +about PKAs. They're like no. So they + + + align:start position:0% +about PKAs. They're like no. So they +contact me and I'm like they did not + + align:start position:0% +contact me and I'm like they did not + + + align:start position:0% +contact me and I'm like they did not +take 511 if they do not know what a PKA + + align:start position:0% +take 511 if they do not know what a PKA + + + align:start position:0% +take 511 if they do not know what a PKA +is. There are other courses that + + align:start position:0% +is. There are other courses that + + + align:start position:0% +is. There are other courses that +sometimes people decide to take that are + + align:start position:0% +sometimes people decide to take that are + + + align:start position:0% +sometimes people decide to take that are +not 511, but in 511, you know about + + align:start position:0% +not 511, but in 511, you know about + + + align:start position:0% +not 511, but in 511, you know about +PKAs. So, what I want you to do is later + + align:start position:0% +PKAs. So, what I want you to do is later + + + align:start position:0% +PKAs. So, what I want you to do is later +in life when you're in a class and pKa's + + align:start position:0% +in life when you're in a class and pKa's + + + align:start position:0% +in life when you're in a class and pKa's +come up and everyone else in the class + + align:start position:0% +come up and everyone else in the class + + + align:start position:0% +come up and everyone else in the class +is like, I don't know. You're like, I + + align:start position:0% +is like, I don't know. You're like, I + + + align:start position:0% +is like, I don't know. You're like, I +took + + align:start position:0% +took + + + align:start position:0% +took +511. I can answer that. That makes me + + align:start position:0% +511. I can answer that. That makes me + + + align:start position:0% +511. I can answer that. That makes me +very happy. Okay, so + + align:start position:0% +very happy. Okay, so + + + align:start position:0% +very happy. Okay, so +pKa's so pKa is minus the log of the Ka. + + align:start position:0% +pKa's so pKa is minus the log of the Ka. + + + align:start position:0% +pKa's so pKa is minus the log of the Ka. +That's easy to remember. We already + + align:start position:0% +That's easy to remember. We already + + + align:start position:0% +That's easy to remember. We already +talked about the relationship of Ka with + + align:start position:0% +talked about the relationship of Ka with + + + align:start position:0% +talked about the relationship of Ka with +strong acids or weak acids. The lower + + align:start position:0% +strong acids or weak acids. The lower + + + align:start position:0% +strong acids or weak acids. The lower +the value of the Ka, the higher the + + align:start position:0% +the value of the Ka, the higher the + + + align:start position:0% +the value of the Ka, the higher the +value of the pKa. That's just out of + + align:start position:0% +value of the pKa. That's just out of + + + align:start position:0% +value of the pKa. That's just out of +that expression. So the higher the pKa + + align:start position:0% +that expression. So the higher the pKa + + + align:start position:0% +that expression. So the higher the pKa +means what about the + + align:start position:0% +means what about the + + + align:start position:0% +means what about the +acid? And think about what you know + + align:start position:0% +acid? And think about what you know + + + align:start position:0% +acid? And think about what you know +about Ka to answer this question. + + align:start position:0% + + + + align:start position:0% + +All right, 10 more + + align:start position:0% + + + + align:start position:0% + +seconds. All + + align:start position:0% +seconds. All + + + align:start position:0% +seconds. All +right. So that is + + align:start position:0% +right. So that is + + + align:start position:0% +right. So that is +correct. So we have a weaker acid. So if + + align:start position:0% +correct. So we have a weaker acid. So if + + + align:start position:0% +correct. So we have a weaker acid. So if +we have a low Ka that means that it is a + + align:start position:0% +we have a low Ka that means that it is a + + + align:start position:0% +we have a low Ka that means that it is a +weak acid and then a higher value of Ka. + + align:start position:0% +weak acid and then a higher value of Ka. + + + align:start position:0% +weak acid and then a higher value of Ka. +So the higher the Ka that's going to + + align:start position:0% +So the higher the Ka that's going to + + + align:start position:0% +So the higher the Ka that's going to +mean um the the lower the value or the + + align:start position:0% +mean um the the lower the value or the + + + align:start position:0% +mean um the the lower the value or the +weaker the + + align:start position:0% +weaker the + + + align:start position:0% +weaker the +acid. So these are just remember the + + align:start position:0% +acid. So these are just remember the + + + align:start position:0% +acid. So these are just remember the +relationship from the equation and think + + align:start position:0% +relationship from the equation and think + + + align:start position:0% +relationship from the equation and think +about it and you can think about the + + align:start position:0% +about it and you can think about the + + + align:start position:0% +about it and you can think about the +value of Ka products over reactants. + + align:start position:0% +value of Ka products over reactants. + + + align:start position:0% +value of Ka products over reactants. +think you might have a lot of products + + align:start position:0% +think you might have a lot of products + + + align:start position:0% +think you might have a lot of products +that means a lot of ionization and a + + align:start position:0% +that means a lot of ionization and a + + + align:start position:0% +that means a lot of ionization and a +stronger acid and fewer products um that + + align:start position:0% +stronger acid and fewer products um that + + + align:start position:0% +stronger acid and fewer products um that +means it's weaker. Okay, so let's look + + align:start position:0% +means it's weaker. Okay, so let's look + + + align:start position:0% +means it's weaker. Okay, so let's look +at some uh tables and I just put the + + align:start position:0% +at some uh tables and I just put the + + + align:start position:0% +at some uh tables and I just put the +values that are with the arrows in your + + align:start position:0% +values that are with the arrows in your + + + align:start position:0% +values that are with the arrows in your +notes. I didn't put the entire table. + + align:start position:0% +notes. I didn't put the entire table. + + + align:start position:0% +notes. I didn't put the entire table. +The tables are in the book and this is + + align:start position:0% +The tables are in the book and this is + + + align:start position:0% +The tables are in the book and this is +like page one of the table. So there's a + + align:start position:0% +like page one of the table. So there's a + + + align:start position:0% +like page one of the table. So there's a +lot of values here. So this has the + + align:start position:0% +lot of values here. So this has the + + + align:start position:0% +lot of values here. So this has the +acid. It tells you what the HA term is, + + align:start position:0% +acid. It tells you what the HA term is, + + + align:start position:0% +acid. It tells you what the HA term is, +what the A minus, so what the weak acid + + align:start position:0% +what the A minus, so what the weak acid + + + align:start position:0% +what the A minus, so what the weak acid +is, what the conjugate base is. It gives + + align:start position:0% +is, what the conjugate base is. It gives + + + align:start position:0% +is, what the conjugate base is. It gives +you the Ka and the pKa. And so you can + + align:start position:0% +you the Ka and the pKa. And so you can + + + align:start position:0% +you the Ka and the pKa. And so you can +see the relationship between um Ka and + + align:start position:0% +see the relationship between um Ka and + + + align:start position:0% +see the relationship between um Ka and +pKa. So up here, HI is at the top of + + align:start position:0% +pKa. So up here, HI is at the top of + + + align:start position:0% +pKa. So up here, HI is at the top of +this table. So that probably means it's + + align:start position:0% +this table. So that probably means it's + + + align:start position:0% +this table. So that probably means it's +the strongest or the weakest. Which do + + align:start position:0% +the strongest or the weakest. Which do + + + align:start position:0% +the strongest or the weakest. Which do +you think? Is this the strongest or the + + align:start position:0% +you think? Is this the strongest or the + + + align:start position:0% +you think? Is this the strongest or the +weakest? You just yell it out. + + align:start position:0% +weakest? You just yell it out. + + + align:start position:0% +weakest? You just yell it out. +It is the strongest. Right. So it has a + + align:start position:0% +It is the strongest. Right. So it has a + + + align:start position:0% +It is the strongest. Right. So it has a +Ka value that is much much much much + + align:start position:0% +Ka value that is much much much much + + + align:start position:0% +Ka value that is much much much much +much much much greater than one and it + + align:start position:0% +much much much greater than one and it + + + align:start position:0% +much much much greater than one and it +has a very very very negative tiny tiny + + align:start position:0% +has a very very very negative tiny tiny + + + align:start position:0% +has a very very very negative tiny tiny +pKa value. So this is a super strong + + align:start position:0% +pKa value. So this is a super strong + + + align:start position:0% +pKa value. So this is a super strong +acid. In fact, do not use that. There's + + align:start position:0% +acid. In fact, do not use that. There's + + + align:start position:0% +acid. In fact, do not use that. There's +no reason really you would ever want to + + align:start position:0% +no reason really you would ever want to + + + align:start position:0% +no reason really you would ever want to +be using it. It is not a good thing to + + align:start position:0% +be using it. It is not a good thing to + + + align:start position:0% +be using it. It is not a good thing to +play with. All right. So HCl um is used + + align:start position:0% +play with. All right. So HCl um is used + + + align:start position:0% +play with. All right. So HCl um is used +more often um in pH things. Um, is this + + align:start position:0% +more often um in pH things. Um, is this + + + align:start position:0% +more often um in pH things. Um, is this +a is this a strong aric acid? + + align:start position:0% +a is this a strong aric acid? + + + align:start position:0% +a is this a strong aric acid? +It's also strong. It's um K or K a is + + align:start position:0% +It's also strong. It's um K or K a is + + + align:start position:0% +It's also strong. It's um K or K a is +also greater than one, but not as strong + + align:start position:0% +also greater than one, but not as strong + + + align:start position:0% +also greater than one, but not as strong +as this. We have 10 to the 7th and that + + align:start position:0% +as this. We have 10 to the 7th and that + + + align:start position:0% +as this. We have 10 to the 7th and that +one. Gosh, I should bring my glasses. 10 + + align:start position:0% +one. Gosh, I should bring my glasses. 10 + + + align:start position:0% +one. Gosh, I should bring my glasses. 10 +to the 11th. That's super strong. That's + + align:start position:0% +to the 11th. That's super strong. That's + + + align:start position:0% +to the 11th. That's super strong. That's +still pretty strong. All right, so let's + + align:start position:0% +still pretty strong. All right, so let's + + + align:start position:0% +still pretty strong. All right, so let's +look down here now. Tell me, is this a + + align:start position:0% +look down here now. Tell me, is this a + + + align:start position:0% +look down here now. Tell me, is this a +strong or weak acid? + + align:start position:0% +strong or weak acid? + + + align:start position:0% +strong or weak acid? +that is a weak acid. the KA is less than + + align:start position:0% +that is a weak acid. the KA is less than + + + align:start position:0% +that is a weak acid. the KA is less than +one here and I think that's like a + + align:start position:0% +one here and I think that's like a + + + align:start position:0% +one here and I think that's like a +minus2 and the pKa value now we're out + + align:start position:0% +minus2 and the pKa value now we're out + + + align:start position:0% +minus2 and the pKa value now we're out +of the negative number so it's on the + + align:start position:0% +of the negative number so it's on the + + + align:start position:0% +of the negative number so it's on the +bigger side and down here is this uh + + align:start position:0% +bigger side and down here is this uh + + + align:start position:0% +bigger side and down here is this uh +strong or + + align:start position:0% +strong or + + + align:start position:0% +strong or +weak also weak and it's even weaker than + + align:start position:0% +weak also weak and it's even weaker than + + + align:start position:0% +weak also weak and it's even weaker than +this one it's like 10 to the minus4 and + + align:start position:0% +this one it's like 10 to the minus4 and + + + align:start position:0% +this one it's like 10 to the minus4 and +pKa value is + + align:start position:0% +pKa value is + + + align:start position:0% +pKa value is +3.75 so you see you can look at the Ka + + align:start position:0% +3.75 so you see you can look at the Ka + + + align:start position:0% +3.75 so you see you can look at the Ka +values vales and think about whether + + align:start position:0% +values vales and think about whether + + + align:start position:0% +values vales and think about whether +it's a strong or weak acid. You can also + + align:start position:0% +it's a strong or weak acid. You can also + + + align:start position:0% +it's a strong or weak acid. You can also +look at the pKa values. This is really + + align:start position:0% +look at the pKa values. This is really + + + align:start position:0% +look at the pKa values. This is really +really small negative value. Um this is + + align:start position:0% +really small negative value. Um this is + + + align:start position:0% +really small negative value. Um this is +a bigger value down here. And this is + + align:start position:0% +a bigger value down here. And this is + + + align:start position:0% +a bigger value down here. And this is +not then the weakest acid. There's a + + align:start position:0% +not then the weakest acid. There's a + + + align:start position:0% +not then the weakest acid. There's a +whole another page of tables um to uh + + align:start position:0% +whole another page of tables um to uh + + + align:start position:0% +whole another page of tables um to uh +for acids. Lots and lots of acids. Okay. + + align:start position:0% +for acids. Lots and lots of acids. Okay. + + + align:start position:0% +for acids. Lots and lots of acids. Okay. +Less ba bases. Um there are there are a + + align:start position:0% +Less ba bases. Um there are there are a + + + align:start position:0% +Less ba bases. Um there are there are a +few and you will see this base quite + + align:start position:0% +few and you will see this base quite + + + align:start position:0% +few and you will see this base quite +often. NH3. + + align:start position:0% +often. NH3. + + + align:start position:0% +often. NH3. +So we have a base in water. The base + + align:start position:0% +So we have a base in water. The base + + + align:start position:0% +So we have a base in water. The base +accepts a hydrogen ion or proton from + + align:start position:0% +accepts a hydrogen ion or proton from + + + align:start position:0% +accepts a hydrogen ion or proton from +the water forming + + align:start position:0% +the water forming + + + align:start position:0% +the water forming +NH4+. And then after water loses its + + align:start position:0% +NH4+. And then after water loses its + + + align:start position:0% +NH4+. And then after water loses its +hydrogen ion, it forms O + + align:start position:0% +hydrogen ion, it forms O + + + align:start position:0% +hydrogen ion, it forms O +minus. So the equilibrium expression or + + align:start position:0% +minus. So the equilibrium expression or + + + align:start position:0% +minus. So the equilibrium expression or +the K for this um base in water problem + + align:start position:0% +the K for this um base in water problem + + + align:start position:0% +the K for this um base in water problem +is called the base ionization constant + + align:start position:0% +is called the base ionization constant + + + align:start position:0% +is called the base ionization constant +or KB. And um we can write that + + align:start position:0% +or KB. And um we can write that + + + align:start position:0% +or KB. And um we can write that +expression here. We have the ammonium + + align:start position:0% +expression here. We have the ammonium + + + align:start position:0% +expression here. We have the ammonium +ion concentration times the hydroxide + + align:start position:0% +ion concentration times the hydroxide + + + align:start position:0% +ion concentration times the hydroxide +ion concentration over the concentration + + align:start position:0% +ion concentration over the concentration + + + align:start position:0% +ion concentration over the concentration +of ammonia. Again, water is not in the + + align:start position:0% +of ammonia. Again, water is not in the + + + align:start position:0% +of ammonia. Again, water is not in the +expression. It stays pretty much pure + + align:start position:0% +expression. It stays pretty much pure + + + align:start position:0% +expression. It stays pretty much pure +throughout this entire thing. It's the + + align:start position:0% +throughout this entire thing. It's the + + + align:start position:0% +throughout this entire thing. It's the +solvent. And so this is our expression + + align:start position:0% +solvent. And so this is our expression + + + align:start position:0% +solvent. And so this is our expression +for KB. And if you're writing an + + align:start position:0% +for KB. And if you're writing an + + + align:start position:0% +for KB. And if you're writing an +expression for KB, you should always + + align:start position:0% +expression for KB, you should always + + + align:start position:0% +expression for KB, you should always +make sure check yourself that you're + + align:start position:0% +make sure check yourself that you're + + + align:start position:0% +make sure check yourself that you're +putting hydroxide ion concentration in + + align:start position:0% +putting hydroxide ion concentration in + + + align:start position:0% +putting hydroxide ion concentration in +there. If it is a base in water, it + + align:start position:0% +there. If it is a base in water, it + + + align:start position:0% +there. If it is a base in water, it +should be forming hydroxide ion + + align:start position:0% +should be forming hydroxide ion + + + align:start position:0% +should be forming hydroxide ion +concentration. If you start writing a KB + + align:start position:0% +concentration. If you start writing a KB + + + align:start position:0% +concentration. If you start writing a KB +and you have hydrronium ion + + align:start position:0% +and you have hydrronium ion + + + align:start position:0% +and you have hydrronium ion +concentration in there, you want to stop + + align:start position:0% +concentration in there, you want to stop + + + align:start position:0% +concentration in there, you want to stop +and rethink what you're doing. Okay. So, + + align:start position:0% +and rethink what you're doing. Okay. So, + + + align:start position:0% +and rethink what you're doing. Okay. So, +in this case, we also have a weak base. + + align:start position:0% +in this case, we also have a weak base. + + + align:start position:0% +in this case, we also have a weak base. +Um 1.8 * 10us 5. It is a small number + + align:start position:0% +Um 1.8 * 10us 5. It is a small number + + + align:start position:0% +Um 1.8 * 10us 5. It is a small number +for KB. It's a small equilibrium number. + + align:start position:0% +for KB. It's a small equilibrium number. + + + align:start position:0% +for KB. It's a small equilibrium number. +So that means you're not a lot of + + align:start position:0% +So that means you're not a lot of + + + align:start position:0% +So that means you're not a lot of +products. Not a lot ionizes when you put + + align:start position:0% +products. Not a lot ionizes when you put + + + align:start position:0% +products. Not a lot ionizes when you put +this weak base in water. So only a tiny + + align:start position:0% +this weak base in water. So only a tiny + + + align:start position:0% +this weak base in water. So only a tiny +amount of NH3 ionizes to NH4 plus and O + + align:start position:0% +amount of NH3 ionizes to NH4 plus and O + + + align:start position:0% +amount of NH3 ionizes to NH4 plus and O +in solution. So this is what they call + + align:start position:0% +in solution. So this is what they call + + + align:start position:0% +in solution. So this is what they call +moderately uh weak base. + + align:start position:0% +moderately uh weak base. + + + align:start position:0% +moderately uh weak base. +So as we saw + + align:start position:0% +So as we saw + + + align:start position:0% +So as we saw +before you can have generic expressions + + align:start position:0% +before you can have generic expressions + + + align:start position:0% +before you can have generic expressions +for a base in water. We can write B + + align:start position:0% +for a base in water. We can write B + + + align:start position:0% +for a base in water. We can write B +aqueous plus water goes to BH+. The base + + align:start position:0% +aqueous plus water goes to BH+. The base + + + align:start position:0% +aqueous plus water goes to BH+. The base +accepts a hydrogen ion or proton and the + + align:start position:0% +accepts a hydrogen ion or proton and the + + + align:start position:0% +accepts a hydrogen ion or proton and the +water loses one forming O minus. We can + + align:start position:0% +water loses one forming O minus. We can + + + align:start position:0% +water loses one forming O minus. We can +also write the expression that often + + align:start position:0% +also write the expression that often + + + align:start position:0% +also write the expression that often +exists from the conjugate of a weak base + + align:start position:0% +exists from the conjugate of a weak base + + + align:start position:0% +exists from the conjugate of a weak base +or conjugate of a weak acid and this is + + align:start position:0% +or conjugate of a weak acid and this is + + + align:start position:0% +or conjugate of a weak acid and this is +a weak base. So a minus plus water goes + + align:start position:0% +a weak base. So a minus plus water goes + + + align:start position:0% +a weak base. So a minus plus water goes +to HA plus hydroxide ion concentration. + + align:start position:0% +to HA plus hydroxide ion concentration. + + + align:start position:0% +to HA plus hydroxide ion concentration. +So either of these are generic + + align:start position:0% +So either of these are generic + + + align:start position:0% +So either of these are generic +expressions that you can write for a + + align:start position:0% +expressions that you can write for a + + + align:start position:0% +expressions that you can write for a +base in + + align:start position:0% +base in + + + align:start position:0% +base in +water. So in terms of the definitions, + + align:start position:0% +water. So in terms of the definitions, + + + align:start position:0% +water. So in terms of the definitions, +it's the same. You would say a strong + + align:start position:0% +it's the same. You would say a strong + + + align:start position:0% +it's the same. You would say a strong +base is something that um ionizes almost + + align:start position:0% +base is something that um ionizes almost + + + align:start position:0% +base is something that um ionizes almost +completely to give O. There aren't a lot + + align:start position:0% +completely to give O. There aren't a lot + + + align:start position:0% +completely to give O. There aren't a lot +of examples of strong bases. Most of the + + align:start position:0% +of examples of strong bases. Most of the + + + align:start position:0% +of examples of strong bases. Most of the +ones you'll see in your class are things + + align:start position:0% +ones you'll see in your class are things + + + align:start position:0% +ones you'll see in your class are things +like um sodium hydroxide. Yes, that is + + align:start position:0% +like um sodium hydroxide. Yes, that is + + + align:start position:0% +like um sodium hydroxide. Yes, that is +hydroxide. That's a strong base. And if + + align:start position:0% +hydroxide. That's a strong base. And if + + + align:start position:0% +hydroxide. That's a strong base. And if +you put it in water, um you should + + align:start position:0% +you put it in water, um you should + + + align:start position:0% +you put it in water, um you should +definitely form a lot of hydroxide. So + + align:start position:0% +definitely form a lot of hydroxide. So + + + align:start position:0% +definitely form a lot of hydroxide. So +um there not a whole lot of examples + + align:start position:0% +um there not a whole lot of examples + + + align:start position:0% +um there not a whole lot of examples +there. So we won't they're not they're + + align:start position:0% +there. So we won't they're not they're + + + align:start position:0% +there. So we won't they're not they're +not all those tables. It's not like it's + + align:start position:0% +not all those tables. It's not like it's + + + align:start position:0% +not all those tables. It's not like it's +not like the acids. All right? But there + + align:start position:0% +not like the acids. All right? But there + + + align:start position:0% +not like the acids. All right? But there +are some terms that you still need to + + align:start position:0% +are some terms that you still need to + + + align:start position:0% +are some terms that you still need to +know. So pKb equals minus log of the KB + + align:start position:0% +know. So pKb equals minus log of the KB + + + align:start position:0% +know. So pKb equals minus log of the KB +And again, the larger the value for KB, + + align:start position:0% +And again, the larger the value for KB, + + + align:start position:0% +And again, the larger the value for KB, +the stronger the base. Again, it tells + + align:start position:0% +the stronger the base. Again, it tells + + + align:start position:0% +the stronger the base. Again, it tells +you you have a lot that have + + align:start position:0% +you you have a lot that have + + + align:start position:0% +you you have a lot that have +ionized. And because of this + + align:start position:0% +ionized. And because of this + + + align:start position:0% +ionized. And because of this +relationship of this equation, the + + align:start position:0% +relationship of this equation, the + + + align:start position:0% +relationship of this equation, the +larger the um pKb, the weaker the base. + + align:start position:0% +larger the um pKb, the weaker the base. + + + align:start position:0% +larger the um pKb, the weaker the base. +Um because if you have a big number + + align:start position:0% +Um because if you have a big number + + + align:start position:0% +Um because if you have a big number +here, you're going to have a small + + align:start position:0% +here, you're going to have a small + + + align:start position:0% +here, you're going to have a small +number + + align:start position:0% +number + + + align:start position:0% +number +there. All right. + + align:start position:0% +there. All right. + + + align:start position:0% +there. All right. +So, now let's talk about conjugate acids + + align:start position:0% +So, now let's talk about conjugate acids + + + align:start position:0% +So, now let's talk about conjugate acids +and their bases. This is super important + + align:start position:0% +and their bases. This is super important + + + align:start position:0% +and their bases. This is super important +for buffers that hopefully we'll get to + + align:start position:0% +for buffers that hopefully we'll get to + + + align:start position:0% +for buffers that hopefully we'll get to +um in class on + + align:start position:0% +um in class on + + + align:start position:0% +um in class on +Friday. So, the stronger the acid, the + + align:start position:0% +Friday. So, the stronger the acid, the + + + align:start position:0% +Friday. So, the stronger the acid, the +weaker its conjugate base. The stronger + + align:start position:0% +weaker its conjugate base. The stronger + + + align:start position:0% +weaker its conjugate base. The stronger +the base, the weaker its conjugate acid. + + align:start position:0% +the base, the weaker its conjugate acid. + + + align:start position:0% +the base, the weaker its conjugate acid. +And here we have HCl, which we + + align:start position:0% +And here we have HCl, which we + + + align:start position:0% +And here we have HCl, which we +determined was a strong acid a little + + align:start position:0% +determined was a strong acid a little + + + align:start position:0% +determined was a strong acid a little +while ago, giving up its hydrogen ion to + + align:start position:0% +while ago, giving up its hydrogen ion to + + + align:start position:0% +while ago, giving up its hydrogen ion to +water, forming hydrronium ion + + align:start position:0% +water, forming hydrronium ion + + + align:start position:0% +water, forming hydrronium ion +concentration, higher hydrononeium ion + + align:start position:0% +concentration, higher hydrononeium ion + + + align:start position:0% +concentration, higher hydrononeium ion +concentration and Cl minus. Cl minus is + + align:start position:0% +concentration and Cl minus. Cl minus is + + + align:start position:0% +concentration and Cl minus. Cl minus is +not a very good conjugate base. It's not + + align:start position:0% +not a very good conjugate base. It's not + + + align:start position:0% +not a very good conjugate base. It's not +a good base. So if we look at this + + align:start position:0% +a good base. So if we look at this + + + align:start position:0% +a good base. So if we look at this +table, when we have a strong acid, its + + align:start position:0% +table, when we have a strong acid, its + + + align:start position:0% +table, when we have a strong acid, its +conjugate is going to be ineffective as + + align:start position:0% +conjugate is going to be ineffective as + + + align:start position:0% +conjugate is going to be ineffective as +a base. you're basically not pushing + + align:start position:0% +a base. you're basically not pushing + + + align:start position:0% +a base. you're basically not pushing +that equilibrium back at all the other + + align:start position:0% +that equilibrium back at all the other + + + align:start position:0% +that equilibrium back at all the other +direction. It's completely ionized and + + align:start position:0% +direction. It's completely ionized and + + + align:start position:0% +direction. It's completely ionized and +it stays that way. But if you have a + + align:start position:0% +it stays that way. But if you have a + + + align:start position:0% +it stays that way. But if you have a +moderately weak acid, you're going to + + align:start position:0% +moderately weak acid, you're going to + + + align:start position:0% +moderately weak acid, you're going to +have a very weak base, a very weak acid, + + align:start position:0% +have a very weak base, a very weak acid, + + + align:start position:0% +have a very weak base, a very weak acid, +you'll have a moderately weak conjugate + + align:start position:0% +you'll have a moderately weak conjugate + + + align:start position:0% +you'll have a moderately weak conjugate +base, a strong base, and you'll have + + align:start position:0% +base, a strong base, and you'll have + + + align:start position:0% +base, a strong base, and you'll have +something that's ineffective as an acid. + + align:start position:0% +something that's ineffective as an acid. + + + align:start position:0% +something that's ineffective as an acid. +So they are inversely related to each + + align:start position:0% +So they are inversely related to each + + + align:start position:0% +So they are inversely related to each +other. So let's think about why this + + align:start position:0% +other. So let's think about why this + + + align:start position:0% +other. So let's think about why this +would be + + align:start position:0% +would be + + + align:start position:0% +would be +true. And this relationship holds. K a + + align:start position:0% +true. And this relationship holds. K a + + + align:start position:0% +true. And this relationship holds. K a +time KB equals K W. And we know that KW + + align:start position:0% +time KB equals K W. And we know that KW + + + align:start position:0% +time KB equals K W. And we know that KW +is 1.0 * + + align:start position:0% +is 1.0 * + + + align:start position:0% +is 1.0 * +10us14th at room + + align:start position:0% +10us14th at room + + + align:start position:0% +10us14th at room +temperature. And if we put logs and then + + align:start position:0% +temperature. And if we put logs and then + + + align:start position:0% +temperature. And if we put logs and then +minus logs by everything, we can derive + + align:start position:0% +minus logs by everything, we can derive + + + align:start position:0% +minus logs by everything, we can derive +this expression, which is the pKa plus + + align:start position:0% +this expression, which is the pKa plus + + + align:start position:0% +this expression, which is the pKa plus +the pKb equals the pKw equals + + align:start position:0% +the pKb equals the pKw equals + + + align:start position:0% +the pKb equals the pKw equals +14.00. So you can't have an acid and its + + align:start position:0% +14.00. So you can't have an acid and its + + + align:start position:0% +14.00. So you can't have an acid and its +conjugate base both be strong. You can't + + align:start position:0% +conjugate base both be strong. You can't + + + align:start position:0% +conjugate base both be strong. You can't +have a base and its conjugate acid both + + align:start position:0% +have a base and its conjugate acid both + + + align:start position:0% +have a base and its conjugate acid both +be strong. The pK's need to add up to + + align:start position:0% +be strong. The pK's need to add up to + + + align:start position:0% +be strong. The pK's need to add up to +14. So, if you have something that's a + + align:start position:0% +14. So, if you have something that's a + + + align:start position:0% +14. So, if you have something that's a +good acid, then its conjugate base is + + align:start position:0% +good acid, then its conjugate base is + + + align:start position:0% +good acid, then its conjugate base is +not going to be particularly good. The + + align:start position:0% +not going to be particularly good. The + + + align:start position:0% +not going to be particularly good. The +pKa A and the pKb must add up to 14. If + + align:start position:0% +pKa A and the pKb must add up to 14. If + + + align:start position:0% +pKa A and the pKb must add up to 14. If +you have something that's a good base, + + align:start position:0% +you have something that's a good base, + + + align:start position:0% +you have something that's a good base, +its conjugate acid is not going to be + + align:start position:0% +its conjugate acid is not going to be + + + align:start position:0% +its conjugate acid is not going to be +that good. So, these are connected to + + align:start position:0% +that good. So, these are connected to + + + align:start position:0% +that good. So, these are connected to +each + + align:start position:0% +each + + + align:start position:0% +each +other. So, we can think about then the + + align:start position:0% +other. So, we can think about then the + + + align:start position:0% +other. So, we can think about then the +strong acids and the strong bases again. + + align:start position:0% +strong acids and the strong bases again. + + + align:start position:0% +strong acids and the strong bases again. +So, we talk about equilibrium, but + + align:start position:0% +So, we talk about equilibrium, but + + + align:start position:0% +So, we talk about equilibrium, but +really this is pushing the equilibrium + + align:start position:0% +really this is pushing the equilibrium + + + align:start position:0% +really this is pushing the equilibrium +pretty much to completion. If it's a + + align:start position:0% +pretty much to completion. If it's a + + + align:start position:0% +pretty much to completion. If it's a +strong acid in water, however much + + align:start position:0% +strong acid in water, however much + + + align:start position:0% +strong acid in water, however much +strong acid you put in is how much + + align:start position:0% +strong acid you put in is how much + + + align:start position:0% +strong acid you put in is how much +hydrronium ion concentration you get + + align:start position:0% +hydrronium ion concentration you get + + + align:start position:0% +hydrronium ion concentration you get +out. A strong base is going to give you + + align:start position:0% +out. A strong base is going to give you + + + align:start position:0% +out. A strong base is going to give you +that amount of hydroxide ion + + align:start position:0% +that amount of hydroxide ion + + + align:start position:0% +that amount of hydroxide ion +concentration. Strong acids and bases + + align:start position:0% +concentration. Strong acids and bases + + + align:start position:0% +concentration. Strong acids and bases +push the equilibrium pretty much + + align:start position:0% +push the equilibrium pretty much + + + align:start position:0% +push the equilibrium pretty much +completely toward ionization. You know, + + align:start position:0% +completely toward ionization. You know, + + + align:start position:0% +completely toward ionization. You know, +we have these numbers of 10 to the 11th, + + align:start position:0% +we have these numbers of 10 to the 11th, + + + align:start position:0% +we have these numbers of 10 to the 11th, +10 to the 7th. These are hugely over + + align:start position:0% +10 to the 7th. These are hugely over + + + align:start position:0% +10 to the 7th. These are hugely over +here. We're forming almost ionizing + + align:start position:0% +here. We're forming almost ionizing + + + align:start position:0% +here. We're forming almost ionizing +completely. Now for weak acids and + + align:start position:0% +completely. Now for weak acids and + + + align:start position:0% +completely. Now for weak acids and +bases, it's very different. Here the + + align:start position:0% +bases, it's very different. Here the + + + align:start position:0% +bases, it's very different. Here the +equilibrium you are going back and + + align:start position:0% +equilibrium you are going back and + + + align:start position:0% +equilibrium you are going back and +forth. You have this dynamic + + align:start position:0% +forth. You have this dynamic + + + align:start position:0% +forth. You have this dynamic +equilibrium. The acid in water is + + align:start position:0% +equilibrium. The acid in water is + + + align:start position:0% +equilibrium. The acid in water is +forming hydrronium ions and and A minus. + + align:start position:0% +forming hydrronium ions and and A minus. + + + align:start position:0% +forming hydrronium ions and and A minus. +But a minus is also a somewhat good weak + + align:start position:0% +But a minus is also a somewhat good weak + + + align:start position:0% +But a minus is also a somewhat good weak +base pushing the equilibrium back the + + align:start position:0% +base pushing the equilibrium back the + + + align:start position:0% +base pushing the equilibrium back the +other way. So in this case we have a + + align:start position:0% +other way. So in this case we have a + + + align:start position:0% +other way. So in this case we have a +back and forth between the forward and + + align:start position:0% +back and forth between the forward and + + + align:start position:0% +back and forth between the forward and +the reverse. So if you have very weak, + + align:start position:0% +the reverse. So if you have very weak, + + + align:start position:0% +the reverse. So if you have very weak, +you have moderate, you have moderate, + + align:start position:0% +you have moderate, you have moderate, + + + align:start position:0% +you have moderate, you have moderate, +you have very weak. And this is what's + + align:start position:0% +you have very weak. And this is what's + + + align:start position:0% +you have very weak. And this is what's +important for forming buffers. And + + align:start position:0% +important for forming buffers. And + + + align:start position:0% +important for forming buffers. And +buffers are really important. Okay, + + align:start position:0% +buffers are really important. Okay, + + + align:start position:0% +buffers are really important. Okay, +let's see if we can uh get to uh one of + + align:start position:0% +let's see if we can uh get to uh one of + + + align:start position:0% +let's see if we can uh get to uh one of +these types of problems because there + + align:start position:0% +these types of problems because there + + + align:start position:0% +these types of problems because there +are five we need to get to in this unit + + align:start position:0% +are five we need to get to in this unit + + + align:start position:0% +are five we need to get to in this unit +and um and there are only five and + + align:start position:0% +and um and there are only five and + + + align:start position:0% +and um and there are only five and +people will say salt and water is + + align:start position:0% +people will say salt and water is + + + align:start position:0% +people will say salt and water is +another but salt and water just breaks + + align:start position:0% +another but salt and water just breaks + + + align:start position:0% +another but salt and water just breaks +down into weak acid and weak bases. So + + align:start position:0% +down into weak acid and weak bases. So + + + align:start position:0% +down into weak acid and weak bases. So +everyone can learn how to do five types + + align:start position:0% +everyone can learn how to do five types + + + align:start position:0% +everyone can learn how to do five types +of problems. So this is very doable. + + align:start position:0% +of problems. So this is very doable. + + + align:start position:0% +of problems. So this is very doable. +All right, so let's just look at + + align:start position:0% +All right, so let's just look at + + + align:start position:0% +All right, so let's just look at +equilibrium of weak acids. And we'll + + align:start position:0% +equilibrium of weak acids. And we'll + + + align:start position:0% +equilibrium of weak acids. And we'll +save weak bases for last time. So a weak + + align:start position:0% +save weak bases for last time. So a weak + + + align:start position:0% +save weak bases for last time. So a weak +acid is vitamin C. And I brought some + + align:start position:0% +acid is vitamin C. And I brought some + + + align:start position:0% +acid is vitamin C. And I brought some +vitamin C here. I tried to do a demo + + align:start position:0% +vitamin C here. I tried to do a demo + + + align:start position:0% +vitamin C here. I tried to do a demo +once and discovered that uh vitamin C is + + align:start position:0% +once and discovered that uh vitamin C is + + + align:start position:0% +once and discovered that uh vitamin C is +it's really coated well. So it does not + + align:start position:0% +it's really coated well. So it does not + + + align:start position:0% +it's really coated well. So it does not +dissolve until it hits the acid of your + + align:start position:0% +dissolve until it hits the acid of your + + + align:start position:0% +dissolve until it hits the acid of your +stomach. So I could not dissolve it. Um + + align:start position:0% +stomach. So I could not dissolve it. Um + + + align:start position:0% +stomach. So I could not dissolve it. Um +so I'll just hold this up right here. + + align:start position:0% +so I'll just hold this up right here. + + + align:start position:0% +so I'll just hold this up right here. +But if we had a uh 500 mgram tablet, + + align:start position:0% +But if we had a uh 500 mgram tablet, + + + align:start position:0% +But if we had a uh 500 mgram tablet, +which I think is what this is, and if I + + align:start position:0% +which I think is what this is, and if I + + + align:start position:0% +which I think is what this is, and if I +had 100 mls of water, and if this wasn't + + align:start position:0% +had 100 mls of water, and if this wasn't + + + align:start position:0% +had 100 mls of water, and if this wasn't +coated, so there's no way you can + + align:start position:0% +coated, so there's no way you can + + + align:start position:0% +coated, so there's no way you can +dissolve it, then I could calculate the + + align:start position:0% +dissolve it, then I could calculate the + + + align:start position:0% +dissolve it, then I could calculate the +pH. So, how am I going to do this? I'm + + align:start position:0% +pH. So, how am I going to do this? I'm + + + align:start position:0% +pH. So, how am I going to do this? I'm +given the Ka. I'm told I'm told the + + align:start position:0% +given the Ka. I'm told I'm told the + + + align:start position:0% +given the Ka. I'm told I'm told the +number of milligrams and I'm told the + + align:start position:0% +number of milligrams and I'm told the + + + align:start position:0% +number of milligrams and I'm told the +volume of water. So, the first thing you + + align:start position:0% +volume of water. So, the first thing you + + + align:start position:0% +volume of water. So, the first thing you +want to do is calculate marity. So you + + align:start position:0% +want to do is calculate marity. So you + + + align:start position:0% +want to do is calculate marity. So you +have you want to convert grams um to + + align:start position:0% +have you want to convert grams um to + + + align:start position:0% +have you want to convert grams um to +moles or milligrams to grams to moles + + align:start position:0% +moles or milligrams to grams to moles + + + align:start position:0% +moles or milligrams to grams to moles +and then you want to use your volume and + + align:start position:0% +and then you want to use your volume and + + + align:start position:0% +and then you want to use your volume and +we have 100 ms but we're going to do + + align:start position:0% +we have 100 ms but we're going to do + + + align:start position:0% +we have 100 ms but we're going to do +marity so we want to convert milliliters + + align:start position:0% +marity so we want to convert milliliters + + + align:start position:0% +marity so we want to convert milliliters +to liters and we can calculate + + align:start position:0% +to liters and we can calculate + + + align:start position:0% +to liters and we can calculate +0.0284 molar moles per liter. + + align:start position:0% +0.0284 molar moles per liter. + + + align:start position:0% +0.0284 molar moles per liter. +Then we can write our expression. And if + + align:start position:0% +Then we can write our expression. And if + + + align:start position:0% +Then we can write our expression. And if +you want to, you can just write HA here + + align:start position:0% +you want to, you can just write HA here + + + align:start position:0% +you want to, you can just write HA here +and A minus. You don't have to write out + + align:start position:0% +and A minus. You don't have to write out + + + align:start position:0% +and A minus. You don't have to write out +the whole thing if you don't want + + align:start position:0% +the whole thing if you don't want + + + align:start position:0% +the whole thing if you don't want +to. All right. So here is the expression + + align:start position:0% +to. All right. So here is the expression + + + align:start position:0% +to. All right. So here is the expression +again. Now just as we saw with chemical + + align:start position:0% +again. Now just as we saw with chemical + + + align:start position:0% +again. Now just as we saw with chemical +equilibrium, we can write this table + + align:start position:0% +equilibrium, we can write this table + + + align:start position:0% +equilibrium, we can write this table +talking about the initial marity. So we + + align:start position:0% +talking about the initial marity. So we + + + align:start position:0% +talking about the initial marity. So we +have a weak acid. We have no hy + + align:start position:0% +have a weak acid. We have no hy + + + align:start position:0% +have a weak acid. We have no hy +hydrronium ion concentration. We have no + + align:start position:0% +hydrronium ion concentration. We have no + + + align:start position:0% +hydrronium ion concentration. We have no +weak conjugate base over here. Um so the + + align:start position:0% +weak conjugate base over here. Um so the + + + align:start position:0% +weak conjugate base over here. Um so the +change then is going to be the constant + + align:start position:0% +change then is going to be the constant + + + align:start position:0% +change then is going to be the constant +the marity that we had and these are + + align:start position:0% +the marity that we had and these are + + + align:start position:0% +the marity that we had and these are +change in marity so don't put don't put + + align:start position:0% +change in marity so don't put don't put + + + align:start position:0% +change in marity so don't put don't put +moles or other things here marity here + + align:start position:0% +moles or other things here marity here + + + align:start position:0% +moles or other things here marity here +min - x that's what you have at + + align:start position:0% +min - x that's what you have at + + + align:start position:0% +min - x that's what you have at +equilibrium plus x plus + + align:start position:0% +equilibrium plus x plus + + + align:start position:0% +equilibrium plus x plus +x so we can write our expression now for + + align:start position:0% +x so we can write our expression now for + + + align:start position:0% +x so we can write our expression now for +Ka we're given the value for Ka and we + + align:start position:0% +Ka we're given the value for Ka and we + + + align:start position:0% +Ka we're given the value for Ka and we +know how to write an expression we have + + align:start position:0% +know how to write an expression we have + + + align:start position:0% +know how to write an expression we have +our hydrronium ion concentration our + + align:start position:0% +our hydrronium ion concentration our + + + align:start position:0% +our hydrronium ion concentration our +conjugate base over here over our + + align:start position:0% +conjugate base over here over our + + + align:start position:0% +conjugate base over here over our +conjugate acid. This is equal to + + align:start position:0% +conjugate acid. This is equal to + + + align:start position:0% +conjugate acid. This is equal to +x^2 + + align:start position:0% +x^2 + + + align:start position:0% +x^2 +0.0284 minus x. Now, if you want to with + + align:start position:0% +0.0284 minus x. Now, if you want to with + + + align:start position:0% +0.0284 minus x. Now, if you want to with +these problems, you can make an + + align:start position:0% +these problems, you can make an + + + align:start position:0% +these problems, you can make an +assumption that x is going to be small + + align:start position:0% +assumption that x is going to be small + + + align:start position:0% +assumption that x is going to be small +and then not have to use the quadratic + + align:start position:0% +and then not have to use the quadratic + + + align:start position:0% +and then not have to use the quadratic +equation, but you do need to check your + + align:start position:0% +equation, but you do need to check your + + + align:start position:0% +equation, but you do need to check your +assumption. But I'll show you how to do + + align:start position:0% +assumption. But I'll show you how to do + + + align:start position:0% +assumption. But I'll show you how to do +it with an assumption. So, we're going + + align:start position:0% +it with an assumption. So, we're going + + + align:start position:0% +it with an assumption. So, we're going +to assume x is small and this value, the + + align:start position:0% +to assume x is small and this value, the + + + align:start position:0% +to assume x is small and this value, the +x will drop out. So we can rewrite this + + align:start position:0% +x will drop out. So we can rewrite this + + + align:start position:0% +x will drop out. So we can rewrite this +expression as x^2 over uh just the + + align:start position:0% +expression as x^2 over uh just the + + + align:start position:0% +expression as x^2 over uh just the +concentration we started with and then + + align:start position:0% +concentration we started with and then + + + align:start position:0% +concentration we started with and then +we can solve for + + align:start position:0% +we can solve for + + + align:start position:0% +we can solve for +x and x in that case is + + align:start position:0% +x and x in that case is + + + align:start position:0% +x and x in that case is +0151 but really two significant figures + + align:start position:0% +0151 but really two significant figures + + + align:start position:0% +0151 but really two significant figures +our ka is just two. Now we can check the + + align:start position:0% +our ka is just two. Now we can check the + + + align:start position:0% +our ka is just two. Now we can check the +assumption and we're going to check the + + align:start position:0% +assumption and we're going to check the + + + align:start position:0% +assumption and we're going to check the +assumption that this is in fact small + + align:start position:0% +assumption that this is in fact small + + + align:start position:0% +assumption that this is in fact small +and if it's less than + + align:start position:0% +and if it's less than + + + align:start position:0% +and if it's less than +5% then we can use + + align:start position:0% +5% then we can use + + + align:start position:0% +5% then we can use +that. So here this is the x we + + align:start position:0% +that. So here this is the x we + + + align:start position:0% +that. So here this is the x we +calculated here is the amount times 100% + + align:start position:0% +calculated here is the amount times 100% + + + align:start position:0% +calculated here is the amount times 100% +gives us + + align:start position:0% +gives us + + + align:start position:0% +gives us +5.3% which is more than five. Five is + + align:start position:0% +5.3% which is more than five. Five is + + + align:start position:0% +5.3% which is more than five. Five is +the magic number for the course. And so + + align:start position:0% +the magic number for the course. And so + + + align:start position:0% +the magic number for the course. And so +then we have to use the quadratic + + align:start position:0% +then we have to use the quadratic + + + align:start position:0% +then we have to use the quadratic +equation. Now, a lot of you probably + + align:start position:0% +equation. Now, a lot of you probably + + + align:start position:0% +equation. Now, a lot of you probably +have calculators that you that can work + + align:start position:0% +have calculators that you that can work + + + align:start position:0% +have calculators that you that can work +the quadratic equation, so you don't + + align:start position:0% +the quadratic equation, so you don't + + + align:start position:0% +the quadratic equation, so you don't +really care. But if you want to check + + align:start position:0% +really care. But if you want to check + + + align:start position:0% +really care. But if you want to check +the assumption, you can. And sometimes + + align:start position:0% +the assumption, you can. And sometimes + + + align:start position:0% +the assumption, you can. And sometimes +we'll need to check it. So, this value, + + align:start position:0% +we'll need to check it. So, this value, + + + align:start position:0% +we'll need to check it. So, this value, +this percent here, is sometimes called + + align:start position:0% +this percent here, is sometimes called + + + align:start position:0% +this percent here, is sometimes called +percent ionization because it's X over + + align:start position:0% +percent ionization because it's X over + + + align:start position:0% +percent ionization because it's X over +the amount you started with. It's the + + align:start position:0% +the amount you started with. It's the + + + align:start position:0% +the amount you started with. It's the +percent that ionized or percent + + align:start position:0% +percent that ionized or percent + + + align:start position:0% +percent that ionized or percent +deproinated. If this is an acid, it's + + align:start position:0% +deproinated. If this is an acid, it's + + + align:start position:0% +deproinated. If this is an acid, it's +the amount of hydrronium, the amount + + align:start position:0% +the amount of hydrronium, the amount + + + align:start position:0% +the amount of hydrronium, the amount +that deproinated over what you started + + align:start position:0% +that deproinated over what you started + + + align:start position:0% +that deproinated over what you started +with. So sometimes you're asked to do + + align:start position:0% +with. So sometimes you're asked to do + + + align:start position:0% +with. So sometimes you're asked to do +this even if you're not checking any + + align:start position:0% +this even if you're not checking any + + + align:start position:0% +this even if you're not checking any +assumptions. All right. So we have to + + align:start position:0% +assumptions. All right. So we have to + + + align:start position:0% +assumptions. All right. So we have to +end with if the clicker question we get + + align:start position:0% +end with if the clicker question we get + + + align:start position:0% +end with if the clicker question we get +here. This is really two significant + + align:start position:0% +here. This is really two significant + + + align:start position:0% +here. This is really two significant +figures. So why don't you tell me how + + align:start position:0% +figures. So why don't you tell me how + + + align:start position:0% +figures. So why don't you tell me how +many significant figures are in your + + align:start position:0% +many significant figures are in your + + + align:start position:0% +many significant figures are in your +answer for pH? + + align:start position:0% + + + + align:start position:0% + +All right, 10 more seconds. + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +Okay. So, uh let's uh take a look at the + + align:start position:0% +Okay. So, uh let's uh take a look at the + + + align:start position:0% +Okay. So, uh let's uh take a look at the +answer here. So, there's the answer. So, + + align:start position:0% +answer here. So, there's the answer. So, + + + align:start position:0% +answer here. So, there's the answer. So, +this had two significant figures, which + + align:start position:0% +this had two significant figures, which + + + align:start position:0% +this had two significant figures, which +means you get two significant figures + + align:start position:0% +means you get two significant figures + + + align:start position:0% +means you get two significant figures +after the decimal point. So, maybe we'll + + align:start position:0% +after the decimal point. So, maybe we'll + + + align:start position:0% +after the decimal point. So, maybe we'll +have one of these in the clicker + + align:start position:0% +have one of these in the clicker + + + align:start position:0% +have one of these in the clicker +competition on Friday. And we'll do uh + + align:start position:0% +competition on Friday. And we'll do uh + + + align:start position:0% +competition on Friday. And we'll do uh +weak bases uh next time. So again, we've + + align:start position:0% +weak bases uh next time. So again, we've + + + align:start position:0% +weak bases uh next time. So again, we've +been studying acid + + align:start position:0% + + + + align:start position:0% + +base and there are only five types of + + align:start position:0% +base and there are only five types of + + + align:start position:0% +base and there are only five types of +acid base + + align:start position:0% +acid base + + + align:start position:0% +acid base +problems. Weak acid in water, which we + + align:start position:0% +problems. Weak acid in water, which we + + + align:start position:0% +problems. Weak acid in water, which we +already did. Check. Weak base and water, + + align:start position:0% +already did. Check. Weak base and water, + + + align:start position:0% +already did. Check. Weak base and water, +which we're going to do right now. And + + align:start position:0% +which we're going to do right now. And + + + align:start position:0% +which we're going to do right now. And +as soon as we're done doing weak base in + + align:start position:0% +as soon as we're done doing weak base in + + + align:start position:0% +as soon as we're done doing weak base in +water, I'm going to explain to you how + + align:start position:0% +water, I'm going to explain to you how + + + align:start position:0% +water, I'm going to explain to you how +salts in water are just weak acid in + + align:start position:0% +salts in water are just weak acid in + + + align:start position:0% +salts in water are just weak acid in +water or weak base and water problems. + + align:start position:0% +water or weak base and water problems. + + + align:start position:0% +water or weak base and water problems. +So, you already know how to do them as + + align:start position:0% +So, you already know how to do them as + + + align:start position:0% +So, you already know how to do them as +soon as I teach you about weak bases. + + align:start position:0% +soon as I teach you about weak bases. + + + align:start position:0% +soon as I teach you about weak bases. +And then we're going to move on and do + + align:start position:0% +And then we're going to move on and do + + + align:start position:0% +And then we're going to move on and do +buffers. Um, and then next week we're + + align:start position:0% +buffers. Um, and then next week we're + + + align:start position:0% +buffers. Um, and then next week we're +going to do strong acids and strong + + align:start position:0% +going to do strong acids and strong + + + align:start position:0% +going to do strong acids and strong +bases. And then you'll have all + + align:start position:0% +bases. And then you'll have all + + + align:start position:0% +bases. And then you'll have all +five. You already have enough that you + + align:start position:0% +five. You already have enough that you + + + align:start position:0% +five. You already have enough that you +can after today's lecture, you can do I + + align:start position:0% +can after today's lecture, you can do I + + + align:start position:0% +can after today's lecture, you can do I +think all the problem set seven except + + align:start position:0% +think all the problem set seven except + + + align:start position:0% +think all the problem set seven except +for the last two questions I believe or + + align:start position:0% +for the last two questions I believe or + + + align:start position:0% +for the last two questions I believe or +at least a large fraction of problem set + + align:start position:0% +at least a large fraction of problem set + + + align:start position:0% +at least a large fraction of problem set +seven. I will warn you that acid base + + align:start position:0% +seven. I will warn you that acid base + + + align:start position:0% +seven. I will warn you that acid base +problems take a lot of a lot of writing + + align:start position:0% +problems take a lot of a lot of writing + + + align:start position:0% +problems take a lot of a lot of writing +and a lot of time to work. One problem + + align:start position:0% +and a lot of time to work. One problem + + + align:start position:0% +and a lot of time to work. One problem +often has like five or six parts to it + + align:start position:0% +often has like five or six parts to it + + + align:start position:0% +often has like five or six parts to it +and they're all time consuming parts + + align:start position:0% +and they're all time consuming parts + + + align:start position:0% +and they're all time consuming parts +pretty much. So don't leave problem set + + align:start position:0% +pretty much. So don't leave problem set + + + align:start position:0% +pretty much. So don't leave problem set +to the last minute. That would be a + + align:start position:0% +to the last minute. That would be a + + + align:start position:0% +to the last minute. That would be a +mistake on this particular problem set. + + align:start position:0% +mistake on this particular problem set. + + + align:start position:0% +mistake on this particular problem set. +Okay. weak + + align:start position:0% +Okay. weak + + + align:start position:0% +Okay. weak +bases, acid base type problem + + align:start position:0% +bases, acid base type problem + + + align:start position:0% +bases, acid base type problem +too. So in this example, we have ammonia + + align:start position:0% +too. So in this example, we have ammonia + + + align:start position:0% +too. So in this example, we have ammonia +NH ammonia + + align:start position:0% +NH ammonia + + + align:start position:0% +NH ammonia +NH3 in water and we measured the pH of + + align:start position:0% +NH3 in water and we measured the pH of + + + align:start position:0% +NH3 in water and we measured the pH of +some solutions before and saw they were + + align:start position:0% +some solutions before and saw they were + + + align:start position:0% +some solutions before and saw they were +basic. We had a pH of I think 12 last + + align:start position:0% +basic. We had a pH of I think 12 last + + + align:start position:0% +basic. We had a pH of I think 12 last +time. And so this conjugate base goes to + + align:start position:0% +time. And so this conjugate base goes to + + + align:start position:0% +time. And so this conjugate base goes to +a conjugate acid. So the base accepts a + + align:start position:0% +a conjugate acid. So the base accepts a + + + align:start position:0% +a conjugate acid. So the base accepts a +hydrogen ion or proton from water + + align:start position:0% +hydrogen ion or proton from water + + + align:start position:0% +hydrogen ion or proton from water +becomes NH4 plus and the water that lost + + align:start position:0% +becomes NH4 plus and the water that lost + + + align:start position:0% +becomes NH4 plus and the water that lost +its hydrogen ion becomes O minus and + + align:start position:0% +its hydrogen ion becomes O minus and + + + align:start position:0% +its hydrogen ion becomes O minus and +that is a base in water problem because + + align:start position:0% +that is a base in water problem because + + + align:start position:0% +that is a base in water problem because +you're forming hydroxide + + align:start position:0% +you're forming hydroxide + + + align:start position:0% +you're forming hydroxide +ions for a base in water. You're talking + + align:start position:0% +ions for a base in water. You're talking + + + align:start position:0% +ions for a base in water. You're talking +about the equilibrium constant for that + + align:start position:0% +about the equilibrium constant for that + + + align:start position:0% +about the equilibrium constant for that +base in water which has a special name + + align:start position:0% +base in water which has a special name + + + align:start position:0% +base in water which has a special name +KB B for base. Um, and it's uh important + + align:start position:0% +KB B for base. Um, and it's uh important + + + align:start position:0% +KB B for base. Um, and it's uh important +to remember the A's and the B's on the + + align:start position:0% +to remember the A's and the B's on the + + + align:start position:0% +to remember the A's and the B's on the +equilibrium constant because it's always + + align:start position:0% +equilibrium constant because it's always + + + align:start position:0% +equilibrium constant because it's always +checking your work. Um, is this a basin + + align:start position:0% +checking your work. Um, is this a basin + + + align:start position:0% +checking your work. Um, is this a basin +water problem? People sometimes try to + + align:start position:0% +water problem? People sometimes try to + + + align:start position:0% +water problem? People sometimes try to +apply Ka's when they should be doing + + align:start position:0% +apply Ka's when they should be doing + + + align:start position:0% +apply Ka's when they should be doing +KBs. So pay attention to basin water, + + align:start position:0% +KBs. So pay attention to basin water, + + + align:start position:0% +KBs. So pay attention to basin water, +we're thinking about KB. So here, if + + align:start position:0% +we're thinking about KB. So here, if + + + align:start position:0% +we're thinking about KB. So here, if +we're going to calculate the pH of a + + align:start position:0% +we're going to calculate the pH of a + + + align:start position:0% +we're going to calculate the pH of a +solution, we have marity of + + align:start position:0% +solution, we have marity of + + + align:start position:0% +solution, we have marity of +0.15 and room temperature. Pretty much + + align:start position:0% +0.15 and room temperature. Pretty much + + + align:start position:0% +0.15 and room temperature. Pretty much +everything's at room temperature. So + + align:start position:0% +everything's at room temperature. So + + + align:start position:0% +everything's at room temperature. So +whenever you're asked to calculate the + + align:start position:0% +whenever you're asked to calculate the + + + align:start position:0% +whenever you're asked to calculate the +pH of a weak base in water, you want to + + align:start position:0% +pH of a weak base in water, you want to + + + align:start position:0% +pH of a weak base in water, you want to +think about at equilibrium, what's the + + align:start position:0% +think about at equilibrium, what's the + + + align:start position:0% +think about at equilibrium, what's the +condition now? What will be the + + align:start position:0% +condition now? What will be the + + + align:start position:0% +condition now? What will be the +condition? What's the change in what + + align:start position:0% +condition? What's the change in what + + + align:start position:0% +condition? What's the change in what +will be the condition at equilibrium? + + align:start position:0% +will be the condition at equilibrium? + + + align:start position:0% +will be the condition at equilibrium? +And so you can make this table. You can + + align:start position:0% +And so you can make this table. You can + + + align:start position:0% +And so you can make this table. You can +write out the expression again. You can + + align:start position:0% +write out the expression again. You can + + + align:start position:0% +write out the expression again. You can +forget about water. Water's our solvent. + + align:start position:0% +forget about water. Water's our solvent. + + + align:start position:0% +forget about water. Water's our solvent. +It's not going to be showing up. Um, and + + align:start position:0% +It's not going to be showing up. Um, and + + + align:start position:0% +It's not going to be showing up. Um, and +then put in our initial marity 0.15. And + + align:start position:0% +then put in our initial marity 0.15. And + + + align:start position:0% +then put in our initial marity 0.15. And +we put zeros in the other categories. + + align:start position:0% +we put zeros in the other categories. + + + align:start position:0% +we put zeros in the other categories. +And uh Oh, why don't you try the rest? + + align:start position:0% + + + + align:start position:0% + +Is it slowing down? + + align:start position:0% +Is it slowing down? + + + align:start position:0% +Is it slowing down? +Okay. All right. Let's just do 10 more + + align:start position:0% +Okay. All right. Let's just do 10 more + + + align:start position:0% +Okay. All right. Let's just do 10 more +seconds. + + align:start position:0% + + + + align:start position:0% + +Yep. Excellent. Sam told me everyone + + align:start position:0% +Yep. Excellent. Sam told me everyone + + + align:start position:0% +Yep. Excellent. Sam told me everyone +responded really + + align:start position:0% +responded really + + + align:start position:0% +responded really +quickly. So that is in fact what you're + + align:start position:0% +quickly. So that is in fact what you're + + + align:start position:0% +quickly. So that is in fact what you're +going to do. We'll put that up here as + + align:start position:0% +going to do. We'll put that up here as + + + align:start position:0% +going to do. We'll put that up here as +well. So we lose some of this minus x. + + align:start position:0% +well. So we lose some of this minus x. + + + align:start position:0% +well. So we lose some of this minus x. +So at equilibrium we have 0.15 minus x + + align:start position:0% +So at equilibrium we have 0.15 minus x + + + align:start position:0% +So at equilibrium we have 0.15 minus x +and we get plus x here and plus x + + align:start position:0% +and we get plus x here and plus x + + + align:start position:0% +and we get plus x here and plus x +there. Now we can write our KB for our + + align:start position:0% +there. Now we can write our KB for our + + + align:start position:0% +there. Now we can write our KB for our +base in water. its products, the + + align:start position:0% +base in water. its products, the + + + align:start position:0% +base in water. its products, the +conjugate acid, + + align:start position:0% +conjugate acid, + + + align:start position:0% +conjugate acid, +NH4+ times the concentration of + + align:start position:0% +NH4+ times the concentration of + + + align:start position:0% +NH4+ times the concentration of +hydroxide ions over NH3. Again, water is + + align:start position:0% +hydroxide ions over NH3. Again, water is + + + align:start position:0% +hydroxide ions over NH3. Again, water is +the solvent. It's not in the + + align:start position:0% +the solvent. It's not in the + + + align:start position:0% +the solvent. It's not in the +equation. And then we can write out this + + align:start position:0% +equation. And then we can write out this + + + align:start position:0% +equation. And then we can write out this +is X, that's X. So we have + + align:start position:0% +is X, that's X. So we have + + + align:start position:0% +is X, that's X. So we have +X2. And then the change in the amount of + + align:start position:0% +X2. And then the change in the amount of + + + align:start position:0% +X2. And then the change in the amount of +the weak base when it's in water is 0.15 + + align:start position:0% +the weak base when it's in water is 0.15 + + + align:start position:0% +the weak base when it's in water is 0.15 +- X. + + align:start position:0% +- X. + + + align:start position:0% +- X. +So at this point you can either use the + + align:start position:0% +So at this point you can either use the + + + align:start position:0% +So at this point you can either use the +quadratic equation or you can make an + + align:start position:0% +quadratic equation or you can make an + + + align:start position:0% +quadratic equation or you can make an +assumption that x is going to be small + + align:start position:0% +assumption that x is going to be small + + + align:start position:0% +assumption that x is going to be small +compared to 0.5. We don't want to make + + align:start position:0% +compared to 0.5. We don't want to make + + + align:start position:0% +compared to 0.5. We don't want to make +the assumption up here. We want to get + + align:start position:0% +the assumption up here. We want to get + + + align:start position:0% +the assumption up here. We want to get +to this point before we try the + + align:start position:0% +to this point before we try the + + + align:start position:0% +to this point before we try the +assumption. And you always need to check + + align:start position:0% +assumption. And you always need to check + + + align:start position:0% +assumption. And you always need to check +your assumptions to make sure they are + + align:start position:0% +your assumptions to make sure they are + + + align:start position:0% +your assumptions to make sure they are +correct. Um but if we use the assumption + + align:start position:0% +correct. Um but if we use the assumption + + + align:start position:0% +correct. Um but if we use the assumption +here just to simplify the math and so + + align:start position:0% +here just to simplify the math and so + + + align:start position:0% +here just to simplify the math and so +the assumption is that this x is small. + + align:start position:0% +the assumption is that this x is small. + + + align:start position:0% +the assumption is that this x is small. +So we can drop that x - x out. Um and + + align:start position:0% +So we can drop that x - x out. Um and + + + align:start position:0% +So we can drop that x - x out. Um and +then we can calculate that x is + + align:start position:0% + + + + align:start position:0% + +0.00164. And then we can check the + + align:start position:0% +0.00164. And then we can check the + + + align:start position:0% +0.00164. And then we can check the +assumption. And that is another clicker + + align:start position:0% +assumption. And that is another clicker + + + align:start position:0% +assumption. And that is another clicker +question. + + align:start position:0% + + + + align:start position:0% + +All right, 10 more seconds. + + align:start position:0% + + + + align:start position:0% + +All + + align:start position:0% +All + + + align:start position:0% +All +right. It is number one. So here you're + + align:start position:0% +right. It is number one. So here you're + + + align:start position:0% +right. It is number one. So here you're +checking the assumption and the way that + + align:start position:0% +checking the assumption and the way that + + + align:start position:0% +checking the assumption and the way that +you check the assumption is that you put + + align:start position:0% +you check the assumption is that you put + + + align:start position:0% +you check the assumption is that you put +x that you've calculated by simplifying + + align:start position:0% +x that you've calculated by simplifying + + + align:start position:0% +x that you've calculated by simplifying +it divide it by the number that you're + + align:start position:0% +it divide it by the number that you're + + + align:start position:0% +it divide it by the number that you're +asking is it smaller than and then times + + align:start position:0% +asking is it smaller than and then times + + + align:start position:0% +asking is it smaller than and then times +100 because our rule is 5%. So if this + + align:start position:0% +100 because our rule is 5%. So if this + + + align:start position:0% +100 because our rule is 5%. So if this +value is greater than 5% of this value + + align:start position:0% +value is greater than 5% of this value + + + align:start position:0% +value is greater than 5% of this value +you need to use the quadratic. If it's + + align:start position:0% +you need to use the quadratic. If it's + + + align:start position:0% +you need to use the quadratic. If it's +less than 5% then you can go ahead and + + align:start position:0% +less than 5% then you can go ahead and + + + align:start position:0% +less than 5% then you can go ahead and +use your assumption. And so this is the + + align:start position:0% +use your assumption. And so this is the + + + align:start position:0% +use your assumption. And so this is the +assumption we're talking about that this + + align:start position:0% +assumption we're talking about that this + + + align:start position:0% +assumption we're talking about that this +number is under 5%. And for acids and + + align:start position:0% +number is under 5%. And for acids and + + + align:start position:0% +number is under 5%. And for acids and +bases, weak acids and bases, it very + + align:start position:0% +bases, weak acids and bases, it very + + + align:start position:0% +bases, weak acids and bases, it very +often is less than 5%. Um because + + align:start position:0% +often is less than 5%. Um because + + + align:start position:0% +often is less than 5%. Um because +they're weak. So there's not a lot of + + align:start position:0% +they're weak. So there's not a lot of + + + align:start position:0% +they're weak. So there's not a lot of +ionization. And this is often referred + + align:start position:0% +ionization. And this is often referred + + + align:start position:0% +ionization. And this is often referred +to as percentage ionization um as well. + + align:start position:0% +to as percentage ionization um as well. + + + align:start position:0% +to as percentage ionization um as well. +All right. So our checking assumption + + align:start position:0% +All right. So our checking assumption + + + align:start position:0% +All right. So our checking assumption +again that X.00164 + + align:start position:0% +again that X.00164 + + + align:start position:0% +again that X.00164 +0164 divided by 0.15 * 100% is 1% 1.1 + + align:start position:0% +0164 divided by 0.15 * 100% is 1% 1.1 + + + align:start position:0% +0164 divided by 0.15 * 100% is 1% 1.1 +and that's less than five. So the + + align:start position:0% +and that's less than five. So the + + + align:start position:0% +and that's less than five. So the +assumption is + + align:start position:0% +assumption is + + + align:start position:0% +assumption is +okay and then we can calculate + + align:start position:0% +okay and then we can calculate + + + align:start position:0% +okay and then we can calculate +um PO because this is a weak base in + + align:start position:0% +um PO because this is a weak base in + + + align:start position:0% +um PO because this is a weak base in +water. So the X that we calculated is + + align:start position:0% +water. So the X that we calculated is + + + align:start position:0% +water. So the X that we calculated is +the amount of hydroxide ion in solution. + + align:start position:0% +the amount of hydroxide ion in solution. + + + align:start position:0% +the amount of hydroxide ion in solution. +So we calculate PO and we get + + align:start position:0% +So we calculate PO and we get + + + align:start position:0% +So we calculate PO and we get +2.79 and that's two significant figures. + + align:start position:0% +2.79 and that's two significant figures. + + + align:start position:0% +2.79 and that's two significant figures. +Everything we had after the decimal + + align:start position:0% +Everything we had after the decimal + + + align:start position:0% +Everything we had after the decimal +because everything um that we had was + + align:start position:0% +because everything um that we had was + + + align:start position:0% +because everything um that we had was +two significant figures. And so this is + + align:start position:0% +two significant figures. And so this is + + + align:start position:0% +two significant figures. And so this is +two significant figures, two significant + + align:start position:0% +two significant figures, two significant + + + align:start position:0% +two significant figures, two significant +figures after the decimal point. And + + align:start position:0% +figures after the decimal point. And + + + align:start position:0% +figures after the decimal point. And +then you need to calculate pH because + + align:start position:0% +then you need to calculate pH because + + + align:start position:0% +then you need to calculate pH because +the problem asked for pH. So this is + + align:start position:0% +the problem asked for pH. So this is + + + align:start position:0% +the problem asked for pH. So this is +again at room temperature. So we can use + + align:start position:0% +again at room temperature. So we can use + + + align:start position:0% +again at room temperature. So we can use +14 minus + + align:start position:0% +14 minus + + + align:start position:0% +14 minus +2.79 is + + align:start position:0% +2.79 is + + + align:start position:0% +2.79 is +11.21. That's our pH. And don't make the + + align:start position:0% +11.21. That's our pH. And don't make the + + + align:start position:0% +11.21. That's our pH. And don't make the +mistake of stopping here forgetting that + + align:start position:0% +mistake of stopping here forgetting that + + + align:start position:0% +mistake of stopping here forgetting that +X is hydroxide ion instead of hydrronium + + align:start position:0% +X is hydroxide ion instead of hydrronium + + + align:start position:0% +X is hydroxide ion instead of hydrronium +ion and tell me that the pH of my weak + + align:start position:0% +ion and tell me that the pH of my weak + + + align:start position:0% +ion and tell me that the pH of my weak +base in solution is + + align:start position:0% +base in solution is + + + align:start position:0% +base in solution is +pH2. So one of the things that's really + + align:start position:0% +pH2. So one of the things that's really + + + align:start position:0% +pH2. So one of the things that's really +good about this unit is that there's + + align:start position:0% +good about this unit is that there's + + + align:start position:0% +good about this unit is that there's +some good checks that you got the right + + align:start position:0% +some good checks that you got the right + + + align:start position:0% +some good checks that you got the right +answer at the end. If you're talking + + align:start position:0% +answer at the end. If you're talking + + + align:start position:0% +answer at the end. If you're talking +about a base in solution, you should + + align:start position:0% +about a base in solution, you should + + + align:start position:0% +about a base in solution, you should +have a pH above what value? Above seven. + + align:start position:0% +have a pH above what value? Above seven. + + + align:start position:0% +have a pH above what value? Above seven. +So, it should be on the basic side of + + align:start position:0% +So, it should be on the basic side of + + + align:start position:0% +So, it should be on the basic side of +neutral. PH7 is neutral. So, it should + + align:start position:0% +neutral. PH7 is neutral. So, it should + + + align:start position:0% +neutral. PH7 is neutral. So, it should +be above seven. And so, if this was your + + align:start position:0% +be above seven. And so, if this was your + + + align:start position:0% +be above seven. And so, if this was your +answer, that for pH, that wouldn't make + + align:start position:0% +answer, that for pH, that wouldn't make + + + align:start position:0% +answer, that for pH, that wouldn't make +a lot of sense. So, always check at the + + align:start position:0% +a lot of sense. So, always check at the + + + align:start position:0% +a lot of sense. So, always check at the +end. And it's fine if you get to an exam + + align:start position:0% +end. And it's fine if you get to an exam + + + align:start position:0% +end. And it's fine if you get to an exam +and you get to the end and you did + + align:start position:0% +and you get to the end and you did + + + align:start position:0% +and you get to the end and you did +something wrong and you realize that + + align:start position:0% +something wrong and you realize that + + + align:start position:0% +something wrong and you realize that +your answer doesn't make any sense. If + + align:start position:0% +your answer doesn't make any sense. If + + + align:start position:0% +your answer doesn't make any sense. If +you write this answer doesn't make any + + align:start position:0% +you write this answer doesn't make any + + + align:start position:0% +you write this answer doesn't make any +sense, but I don't have time to figure + + align:start position:0% +sense, but I don't have time to figure + + + align:start position:0% +sense, but I don't have time to figure +out what I gave wrong, you will get + + align:start position:0% +out what I gave wrong, you will get + + + align:start position:0% +out what I gave wrong, you will get +points for recognizing that that is not + + align:start position:0% +points for recognizing that that is not + + + align:start position:0% +points for recognizing that that is not +a a valid answer because it's a weak + + align:start position:0% +a a valid answer because it's a weak + + + align:start position:0% +a a valid answer because it's a weak +acid problem and you have a basic pH or + + align:start position:0% +acid problem and you have a basic pH or + + + align:start position:0% +acid problem and you have a basic pH or +vice versa. So, keep that that in mind. + + align:start position:0% +vice versa. So, keep that that in mind. + + + align:start position:0% +vice versa. So, keep that that in mind. +There's lots of partial credit. Grading + + align:start position:0% +There's lots of partial credit. Grading + + + align:start position:0% +There's lots of partial credit. Grading +acidbased problems on exams is a whole + + align:start position:0% +acidbased problems on exams is a whole + + + align:start position:0% +acidbased problems on exams is a whole +new fun adventure that the TAs have no + + align:start position:0% +new fun adventure that the TAs have no + + + align:start position:0% +new fun adventure that the TAs have no +idea what they're what what what is + + align:start position:0% +idea what they're what what what is + + + align:start position:0% +idea what they're what what what is +going to be happening. But I'll be right + + align:start position:0% +going to be happening. But I'll be right + + + align:start position:0% +going to be happening. But I'll be right +with you there for 10 hours of grading + + align:start position:0% +with you there for 10 hours of grading + + + align:start position:0% +with you there for 10 hours of grading +and we'll have a good time. Write + + align:start position:0% +and we'll have a good time. Write + + + align:start position:0% +and we'll have a good time. Write +neatly, please. \ No newline at end of file diff --git a/q0PxCQWG3ic.txt b/q0PxCQWG3ic.txt new file mode 100644 index 0000000000000000000000000000000000000000..97f143e106cd600cbe4fb1dfae4230583a4a00ed --- /dev/null +++ b/q0PxCQWG3ic.txt @@ -0,0 +1,1643 @@ +align:start position:0% + +So in this recitation we're going to + + align:start position:0% +So in this recitation we're going to + + + align:start position:0% +So in this recitation we're going to +look at step and delta functions + + align:start position:0% +look at step and delta functions + + + align:start position:0% +look at step and delta functions +integration and generalized derivatives. + + align:start position:0% +integration and generalized derivatives. + + + align:start position:0% +integration and generalized derivatives. +So the first part you're asked to + + align:start position:0% +So the first part you're asked to + + + align:start position:0% +So the first part you're asked to +compute the integral from 0 minus to + + align:start position:0% +compute the integral from 0 minus to + + + align:start position:0% +compute the integral from 0 minus to +infinity delta t exponential t ^ 2 dt. + + align:start position:0% +infinity delta t exponential t ^ 2 dt. + + + align:start position:0% +infinity delta t exponential t ^ 2 dt. +The second one is from z minus to + + align:start position:0% +The second one is from z minus to + + + align:start position:0% +The second one is from z minus to +infinity delta t minus 2 exponential of + + align:start position:0% +infinity delta t minus 2 exponential of + + + align:start position:0% +infinity delta t minus 2 exponential of +t ^ 2 sin t cos 2t. The third one is 0 + + align:start position:0% +t ^ 2 sin t cos 2t. The third one is 0 + + + align:start position:0% +t ^ 2 sin t cos 2t. The third one is 0 +plus to infinity delta t exponential of + + align:start position:0% +plus to infinity delta t exponential of + + + align:start position:0% +plus to infinity delta t exponential of +t ^ square dt. So note that it's the + + align:start position:0% +t ^ square dt. So note that it's the + + + align:start position:0% +t ^ square dt. So note that it's the +first is the same as a except that the + + align:start position:0% +first is the same as a except that the + + + align:start position:0% +first is the same as a except that the +bounds of integration changed. The + + align:start position:0% +bounds of integration changed. The + + + align:start position:0% +bounds of integration changed. The +second part we're asked to find the + + align:start position:0% +second part we're asked to find the + + + align:start position:0% +second part we're asked to find the +generalized derivatives of these two + + align:start position:0% +generalized derivatives of these two + + + align:start position:0% +generalized derivatives of these two +functions where u here is just a step + + align:start position:0% +functions where u here is just a step + + + align:start position:0% +functions where u here is just a step +function that you saw before. And uh + + align:start position:0% +function that you saw before. And uh + + + align:start position:0% +function that you saw before. And uh +yeah so it's 3 u t minus 2 u t minus one + + align:start position:0% +yeah so it's 3 u t minus 2 u t minus one + + + align:start position:0% +yeah so it's 3 u t minus 2 u t minus one +and the second one is t² for t negative + + align:start position:0% +and the second one is t² for t negative + + + align:start position:0% +and the second one is t² for t negative +and exponential minus t for t positive. + + align:start position:0% +and exponential minus t for t positive. + + + align:start position:0% +and exponential minus t for t positive. +So, why don't you pause the video and + + align:start position:0% +So, why don't you pause the video and + + + align:start position:0% +So, why don't you pause the video and +work through this example, and I'll be + + align:start position:0% +work through this example, and I'll be + + + align:start position:0% +work through this example, and I'll be +right + + align:start position:0% + + + + align:start position:0% + +back. Welcome back. So, let's compute + + align:start position:0% +back. Welcome back. So, let's compute + + + align:start position:0% +back. Welcome back. So, let's compute +the first + + align:start position:0% + + + + align:start position:0% + +one. 0 minus + + align:start position:0% +one. 0 minus + + + align:start position:0% +one. 0 minus +infinity delta t exponential + + align:start position:0% +infinity delta t exponential + + + align:start position:0% +infinity delta t exponential +t² dt. So just to remind + + align:start position:0% +t² dt. So just to remind + + + align:start position:0% +t² dt. So just to remind +you the delta function is everywhere + + align:start position:0% +you the delta function is everywhere + + + align:start position:0% +you the delta function is everywhere +zero except at the value zero and we're + + align:start position:0% +zero except at the value zero and we're + + + align:start position:0% +zero except at the value zero and we're +represented with an + + align:start position:0% +represented with an + + + align:start position:0% +represented with an +arrow and the integral of the delta + + align:start position:0% +arrow and the integral of the delta + + + align:start position:0% +arrow and the integral of the delta +would be one from minus infinity to plus + + align:start position:0% +would be one from minus infinity to plus + + + align:start position:0% +would be one from minus infinity to plus +infinity. In this in this integral we're + + align:start position:0% +infinity. In this in this integral we're + + + align:start position:0% +infinity. In this in this integral we're +integrating from 0 minus to infinity + + align:start position:0% +integrating from 0 minus to infinity + + + align:start position:0% +integrating from 0 minus to infinity +which means that the zero is included in + + align:start position:0% +which means that the zero is included in + + + align:start position:0% +which means that the zero is included in +our interval from 0 minus to infinity. + + align:start position:0% +our interval from 0 minus to infinity. + + + align:start position:0% +our interval from 0 minus to infinity. +Therefore, this integral is basically + + align:start position:0% +Therefore, this integral is basically + + + align:start position:0% +Therefore, this integral is basically +assigning the value to this function + + align:start position:0% +assigning the value to this function + + + align:start position:0% +assigning the value to this function +exponential t² and the value that it's + + align:start position:0% +exponential t² and the value that it's + + + align:start position:0% +exponential t² and the value that it's +assigning to it is the value would take + + align:start position:0% +assigning to it is the value would take + + + align:start position:0% +assigning to it is the value would take +at t equals to zero where the delta is + + align:start position:0% +at t equals to zero where the delta is + + + align:start position:0% +at t equals to zero where the delta is +non zero. And so really clearly this is + + align:start position:0% +non zero. And so really clearly this is + + + align:start position:0% +non zero. And so really clearly this is +just exponential of + + align:start position:0% +just exponential of + + + align:start position:0% +just exponential of +zero and is give us + + align:start position:0% +zero and is give us + + + align:start position:0% +zero and is give us +one. For the second one + + align:start position:0% +one. For the second one + + + align:start position:0% +one. For the second one +integral goes from 0 minus to infinity + + align:start position:0% +integral goes from 0 minus to infinity + + + align:start position:0% +integral goes from 0 minus to infinity +delta t minus 2 exponential a more + + align:start position:0% +delta t minus 2 exponential a more + + + align:start position:0% +delta t minus 2 exponential a more +complicated function t ^ + + align:start position:0% +complicated function t ^ + + + align:start position:0% +complicated function t ^ +2 sin + + align:start position:0% +2 sin + + + align:start position:0% +2 sin +t cos 2t. So now let's represent this + + align:start position:0% +t cos 2t. So now let's represent this + + + align:start position:0% +t cos 2t. So now let's represent this +delta function here. + + align:start position:0% +delta function here. + + + align:start position:0% +delta function here. +So this is just our zero axis and the + + align:start position:0% +So this is just our zero axis and the + + + align:start position:0% +So this is just our zero axis and the +delta here is zero everywhere except at + + align:start position:0% +delta here is zero everywhere except at + + + align:start position:0% +delta here is zero everywhere except at +two where we would represent it again + + align:start position:0% +two where we would represent it again + + + align:start position:0% +two where we would represent it again +with an arrow and amplitude one. Okay. + + align:start position:0% +with an arrow and amplitude one. Okay. + + + align:start position:0% +with an arrow and amplitude one. Okay. +So this delta is zero everywhere except + + align:start position:0% +So this delta is zero everywhere except + + + align:start position:0% +So this delta is zero everywhere except +at two where it would assign the value + + align:start position:0% +at two where it would assign the value + + + align:start position:0% +at two where it would assign the value +to the function next to it at the value + + align:start position:0% +to the function next to it at the value + + + align:start position:0% +to the function next to it at the value +t equals to two. So really this + + align:start position:0% +t equals to two. So really this + + + align:start position:0% +t equals to two. So really this +integration gives us + + align:start position:0% +integration gives us + + + align:start position:0% +integration gives us +just the value of this function at t = + + align:start position:0% +just the value of this function at t = + + + align:start position:0% +just the value of this function at t = +2. So 4 sin + + align:start position:0% +2. So 4 sin + + + align:start position:0% +2. So 4 sin +2 cos + + align:start position:0% +2 cos + + + align:start position:0% +2 cos +4 and here the key was that again this + + align:start position:0% +4 and here the key was that again this + + + align:start position:0% +4 and here the key was that again this +interval of integration from 0 minus to + + align:start position:0% +interval of integration from 0 minus to + + + align:start position:0% +interval of integration from 0 minus to +infinity and clearly includes the value + + align:start position:0% +infinity and clearly includes the value + + + align:start position:0% +infinity and clearly includes the value +at which delta function is non zero. So + + align:start position:0% +at which delta function is non zero. So + + + align:start position:0% +at which delta function is non zero. So +for the last + + align:start position:0% +for the last + + + align:start position:0% +for the last +one, we return to our first integral + + align:start position:0% +one, we return to our first integral + + + align:start position:0% +one, we return to our first integral +except that now we're changing the + + align:start position:0% +except that now we're changing the + + + align:start position:0% +except that now we're changing the +bounds of integration 0 plus to + + align:start position:0% + + + + align:start position:0% + +infinity. So now if I do a + + align:start position:0% +infinity. So now if I do a + + + align:start position:0% +infinity. So now if I do a +representation of the delta function + + align:start position:0% +representation of the delta function + + + align:start position:0% +representation of the delta function +that we are dealing with. So delta + + align:start position:0% +that we are dealing with. So delta + + + align:start position:0% +that we are dealing with. So delta +centered at one and the interval of + + align:start position:0% +centered at one and the interval of + + + align:start position:0% +centered at one and the interval of +integration. We have an open interval. + + align:start position:0% +integration. We have an open interval. + + + align:start position:0% +integration. We have an open interval. +Now that does not include the value at + + align:start position:0% +Now that does not include the value at + + + align:start position:0% +Now that does not include the value at +which delta is not equal to zero. So + + align:start position:0% +which delta is not equal to zero. So + + + align:start position:0% +which delta is not equal to zero. So +everywhere this function would just be + + align:start position:0% +everywhere this function would just be + + + align:start position:0% +everywhere this function would just be +assigned its value at it just be + + align:start position:0% +assigned its value at it just be + + + align:start position:0% +assigned its value at it just be +multiplied by the function that is zero. + + align:start position:0% +multiplied by the function that is zero. + + + align:start position:0% +multiplied by the function that is zero. +And so basically it's like multiplying + + align:start position:0% +And so basically it's like multiplying + + + align:start position:0% +And so basically it's like multiplying +this function by zero and it just gives + + align:start position:0% +this function by zero and it just gives + + + align:start position:0% +this function by zero and it just gives +us zero. It's like the delta fell off of + + align:start position:0% +us zero. It's like the delta fell off of + + + align:start position:0% +us zero. It's like the delta fell off of +our interval of integration. So we're + + align:start position:0% +our interval of integration. So we're + + + align:start position:0% +our interval of integration. So we're +just left with a zero + + align:start position:0% +just left with a zero + + + align:start position:0% +just left with a zero +function. So let's move to the second + + align:start position:0% + + + + align:start position:0% + +part. The second part asks us to find + + align:start position:0% +part. The second part asks us to find + + + align:start position:0% +part. The second part asks us to find +the generalized + + align:start position:0% +the generalized + + + align:start position:0% +the generalized +derivative 2 f of t equals 3 u + + align:start position:0% +derivative 2 f of t equals 3 u + + + align:start position:0% +derivative 2 f of t equals 3 u +t minus 2 u t minus one. + + align:start position:0% +t minus 2 u t minus one. + + + align:start position:0% +t minus 2 u t minus one. +So just to remind you here of what the U + + align:start position:0% +So just to remind you here of what the U + + + align:start position:0% +So just to remind you here of what the U +of Ts are just want to + + align:start position:0% +of Ts are just want to + + + align:start position:0% +of Ts are just want to +sketch a few + + align:start position:0% +sketch a few + + + align:start position:0% +sketch a few +things. So first + + align:start position:0% +things. So first + + + align:start position:0% +things. So first +uft is just the step function that would + + align:start position:0% +uft is just the step function that would + + + align:start position:0% +uft is just the step function that would +be zero everywhere and would take the + + align:start position:0% +be zero everywhere and would take the + + + align:start position:0% +be zero everywhere and would take the +value one for t larger than zero. So + + align:start position:0% +value one for t larger than zero. So + + + align:start position:0% +value one for t larger than zero. So +this first part here would just be non + + align:start position:0% +this first part here would just be non + + + align:start position:0% +this first part here would just be non +zero for t larger than zero. Instead of + + align:start position:0% +zero for t larger than zero. Instead of + + + align:start position:0% +zero for t larger than zero. Instead of +being assigned value one, it's just be + + align:start position:0% +being assigned value one, it's just be + + + align:start position:0% +being assigned value one, it's just be +assigned value three because we're + + align:start position:0% +assigned value three because we're + + + align:start position:0% +assigned value three because we're +multiplying the u of t by three. So this + + align:start position:0% +multiplying the u of t by three. So this + + + align:start position:0% +multiplying the u of t by three. So this +first part would look like this. The + + align:start position:0% +first part would look like this. The + + + align:start position:0% +first part would look like this. The +second part here would be u shifted to t + + align:start position:0% +second part here would be u shifted to t + + + align:start position:0% +second part here would be u shifted to t +t t t t t t t t t t t t t t t t t t t t + + align:start position:0% +t t t t t t t t t t t t t t t t t t t t + + + align:start position:0% +t t t t t t t t t t t t t t t t t t t t +t t t t t t t t t t t t t t t t t t t t + + align:start position:0% +t t t t t t t t t t t t t t t t t t t t + + + align:start position:0% +t t t t t t t t t t t t t t t t t t t t +t by by minus one, which means that u is + + align:start position:0% +t by by minus one, which means that u is + + + align:start position:0% +t by by minus one, which means that u is +zero everywhere for t less than one. So + + align:start position:0% +zero everywhere for t less than one. So + + + align:start position:0% +zero everywhere for t less than one. So +it would have zero function here. So let + + align:start position:0% +it would have zero function here. So let + + + align:start position:0% +it would have zero function here. So let +me just do + + align:start position:0% +me just do + + + align:start position:0% +me just do +dots but it should be on the same axis + + align:start position:0% +dots but it should be on the same axis + + + align:start position:0% +dots but it should be on the same axis +and one for t larger than one. But here + + align:start position:0% +and one for t larger than one. But here + + + align:start position:0% +and one for t larger than one. But here +we're giving it multiplying it by factor + + align:start position:0% +we're giving it multiplying it by factor + + + align:start position:0% +we're giving it multiplying it by factor +minus two. So really what we + + align:start position:0% + + + + align:start position:0% + +have is another + + align:start position:0% +have is another + + + align:start position:0% +have is another +u function that is shifted + + align:start position:0% +u function that is shifted + + + align:start position:0% +u function that is shifted +down 2 minus 2. So the sum of these two + + align:start position:0% +down 2 minus 2. So the sum of these two + + + align:start position:0% +down 2 minus 2. So the sum of these two +contributions is zero for t negative + + align:start position:0% +contributions is zero for t negative + + + align:start position:0% +contributions is zero for t negative +takes the value three for t between 0 + + align:start position:0% +takes the value three for t between 0 + + + align:start position:0% +takes the value three for t between 0 +and + + align:start position:0% +and + + + align:start position:0% +and +one and a value one 3 minus 2 + + align:start position:0% +one and a value one 3 minus 2 + + + align:start position:0% +one and a value one 3 minus 2 +for t larger than one. Okay, so clearly + + align:start position:0% +for t larger than one. Okay, so clearly + + + align:start position:0% +for t larger than one. Okay, so clearly +here we have discontinuities at t= to0 + + align:start position:0% +here we have discontinuities at t= to0 + + + align:start position:0% +here we have discontinuities at t= to0 +and t= to 1. So let's just write down + + align:start position:0% +and t= to 1. So let's just write down + + + align:start position:0% +and t= to 1. So let's just write down +the + + align:start position:0% +the + + + align:start position:0% +the +derivative. The generalized derivative + + align:start position:0% +derivative. The generalized derivative + + + align:start position:0% +derivative. The generalized derivative +here would lead us first to compute the + + align:start position:0% +here would lead us first to compute the + + + align:start position:0% +here would lead us first to compute the +derivatives when where the function is + + align:start position:0% +derivatives when where the function is + + + align:start position:0% +derivatives when where the function is +continuous. So from minus infinity to + + align:start position:0% +continuous. So from minus infinity to + + + align:start position:0% +continuous. So from minus infinity to +zero, it's a constant. So derivative + + align:start position:0% +zero, it's a constant. So derivative + + + align:start position:0% +zero, it's a constant. So derivative +would be zero. Between 0 and one, it's + + align:start position:0% +would be zero. Between 0 and one, it's + + + align:start position:0% +would be zero. Between 0 and one, it's +constant. Derivative would be zero. And + + align:start position:0% +constant. Derivative would be zero. And + + + align:start position:0% +constant. Derivative would be zero. And +from one to infinity, it would also give + + align:start position:0% +from one to infinity, it would also give + + + align:start position:0% +from one to infinity, it would also give +us zero. So we would have a zero + + align:start position:0% +us zero. So we would have a zero + + + align:start position:0% +us zero. So we would have a zero +contribution from the the continuous + + align:start position:0% +contribution from the the continuous + + + align:start position:0% +contribution from the the continuous +part of the function if you wish but we + + align:start position:0% +part of the function if you wish but we + + + align:start position:0% +part of the function if you wish but we +still need to account for the + + align:start position:0% +still need to account for the + + + align:start position:0% +still need to account for the +discontinuities. So at zero we have a + + align:start position:0% +discontinuities. So at zero we have a + + + align:start position:0% +discontinuities. So at zero we have a +jump from zero to three and that we + + align:start position:0% +jump from zero to three and that we + + + align:start position:0% +jump from zero to three and that we +learned can be written down as a delta + + align:start position:0% +learned can be written down as a delta + + + align:start position:0% +learned can be written down as a delta +function of magnitude three centered at + + align:start position:0% +function of magnitude three centered at + + + align:start position:0% +function of magnitude three centered at +zero. After that we have another jump. + + align:start position:0% +zero. After that we have another jump. + + + align:start position:0% +zero. After that we have another jump. +Now it's from three to one. So it's a + + align:start position:0% +Now it's from three to one. So it's a + + + align:start position:0% +Now it's from three to one. So it's a +jump of minus2 amplitude centered at + + align:start position:0% +jump of minus2 amplitude centered at + + + align:start position:0% +jump of minus2 amplitude centered at +one. So here we can also do that with + + align:start position:0% +one. So here we can also do that with + + + align:start position:0% +one. So here we can also do that with +delta but we just need also to shift it + + align:start position:0% +delta but we just need also to shift it + + + align:start position:0% +delta but we just need also to shift it +by minus one to to show clearly that the + + align:start position:0% +by minus one to to show clearly that the + + + align:start position:0% +by minus one to to show clearly that the +jump occurs at one and multiply this by + + align:start position:0% +jump occurs at one and multiply this by + + + align:start position:0% +jump occurs at one and multiply this by +minus2 to show the amplitude of the jump + + align:start position:0% +minus2 to show the amplitude of the jump + + + align:start position:0% +minus2 to show the amplitude of the jump +down. Okay. So if we were now to + + align:start position:0% +down. Okay. So if we were now to + + + align:start position:0% +down. Okay. So if we were now to +represent it + + align:start position:0% + + + + align:start position:0% + +fprime basically the regular part zero + + align:start position:0% +fprime basically the regular part zero + + + align:start position:0% +fprime basically the regular part zero +so there's nothing to to write down + + align:start position:0% +so there's nothing to to write down + + + align:start position:0% +so there's nothing to to write down +except just a zero function and the + + align:start position:0% +except just a zero function and the + + + align:start position:0% +except just a zero function and the +discontinuities that I'm just going to + + align:start position:0% +discontinuities that I'm just going to + + + align:start position:0% +discontinuities that I'm just going to +represent on the graph would be the + + align:start position:0% +represent on the graph would be the + + + align:start position:0% +represent on the graph would be the +delta function centered at zero of + + align:start position:0% +delta function centered at zero of + + + align:start position:0% +delta function centered at zero of +magnitude + + align:start position:0% +magnitude + + + align:start position:0% +magnitude +3 and delta function centered around one + + align:start position:0% +3 and delta function centered around one + + + align:start position:0% +3 and delta function centered around one +of magnitude minus + + align:start position:0% +of magnitude minus + + + align:start position:0% +of magnitude minus +2 and the rest would just be the zero + + align:start position:0% +2 and the rest would just be the zero + + + align:start position:0% +2 and the rest would just be the zero +function. So that would be f + + align:start position:0% +function. So that would be f + + + align:start position:0% +function. So that would be f +prime that's f of + + align:start position:0% +prime that's f of + + + align:start position:0% +prime that's f of +t. So for the second + + align:start position:0% + + + + align:start position:0% + +one that we were given, it's a function + + align:start position:0% +one that we were given, it's a function + + + align:start position:0% +one that we were given, it's a function +f of + + align:start position:0% +f of + + + align:start position:0% +f of +t that takes the value t² for t negative + + align:start position:0% +t that takes the value t² for t negative + + + align:start position:0% +t that takes the value t² for t negative +and + + align:start position:0% +and + + + align:start position:0% +and +exponential minus + + align:start position:0% + + + + align:start position:0% + +t for t positive. + + align:start position:0% +t for t positive. + + + align:start position:0% +t for t positive. +So quick sketch here tells that this + + align:start position:0% +So quick sketch here tells that this + + + align:start position:0% +So quick sketch here tells that this +function looks like this an exponential + + align:start position:0% +function looks like this an exponential + + + align:start position:0% +function looks like this an exponential +minus t for t positive. Okay, taking a + + align:start position:0% +minus t for t positive. Okay, taking a + + + align:start position:0% +minus t for t positive. Okay, taking a +value here one. So clearly there is a + + align:start position:0% +value here one. So clearly there is a + + + align:start position:0% +value here one. So clearly there is a +jump + + align:start position:0% +jump + + + align:start position:0% +jump +here this + + align:start position:0% +here this + + + align:start position:0% +here this +continuity. So how do we go about + + align:start position:0% +continuity. So how do we go about + + + align:start position:0% +continuity. So how do we go about +computing this generalized derivative? + + align:start position:0% +computing this generalized derivative? + + + align:start position:0% +computing this generalized derivative? +So let's look again at the continuous + + align:start position:0% +So let's look again at the continuous + + + align:start position:0% +So let's look again at the continuous +parts. So from minus infinity to zero, + + align:start position:0% +parts. So from minus infinity to zero, + + + align:start position:0% +parts. So from minus infinity to zero, +we're dealing with just a t square. So + + align:start position:0% +we're dealing with just a t square. So + + + align:start position:0% +we're dealing with just a t square. So +the derivative is just + + align:start position:0% + + + + align:start position:0% + +2t. For t between 0 and infinity, we're + + align:start position:0% +2t. For t between 0 and infinity, we're + + + align:start position:0% +2t. For t between 0 and infinity, we're +just dealing with exponential minus t. + + align:start position:0% +just dealing with exponential minus t. + + + align:start position:0% +just dealing with exponential minus t. +So that's minus exponential minus + + align:start position:0% +So that's minus exponential minus + + + align:start position:0% +So that's minus exponential minus +t. But we need to account for the + + align:start position:0% +t. But we need to account for the + + + align:start position:0% +t. But we need to account for the +discontinuity, the jump of amplitude one + + align:start position:0% +discontinuity, the jump of amplitude one + + + align:start position:0% +discontinuity, the jump of amplitude one +at zero. So as we saw before, this can + + align:start position:0% +at zero. So as we saw before, this can + + + align:start position:0% +at zero. So as we saw before, this can +just be + + align:start position:0% +just be + + + align:start position:0% +just be +modeled with a delta function. And if we + + align:start position:0% +modeled with a delta function. And if we + + + align:start position:0% +modeled with a delta function. And if we +were to represent this function, then we + + align:start position:0% +were to represent this function, then we + + + align:start position:0% +were to represent this function, then we +would just + + align:start position:0% +would just + + + align:start position:0% +would just +need to add a delta + + align:start position:0% +need to add a delta + + + align:start position:0% +need to add a delta +function of magnitude one here and then + + align:start position:0% +function of magnitude one here and then + + + align:start position:0% +function of magnitude one here and then +just sketch 2t. So for + + align:start position:0% +just sketch 2t. So for + + + align:start position:0% +just sketch 2t. So for +example and then minus exponential minus + + align:start position:0% +example and then minus exponential minus + + + align:start position:0% +example and then minus exponential minus +2t that would give us something like + + align:start position:0% +2t that would give us something like + + + align:start position:0% +2t that would give us something like +that. And that ends the problem for + + align:start position:0% +that. And that ends the problem for + + + align:start position:0% +that. And that ends the problem for +today. And the key points here were just + + align:start position:0% +today. And the key points here were just + + + align:start position:0% +today. And the key points here were just +to learn how to manipulate the the step + + align:start position:0% +to learn how to manipulate the the step + + + align:start position:0% +to learn how to manipulate the the step +function and how to use the delta + + align:start position:0% +function and how to use the delta + + + align:start position:0% +function and how to use the delta +function when you compute your integrals + + align:start position:0% +function when you compute your integrals + + + align:start position:0% +function when you compute your integrals +and be careful with the bounds of + + align:start position:0% +and be careful with the bounds of + + + align:start position:0% +and be careful with the bounds of +integration. \ No newline at end of file diff --git a/q785KV5ZIN0.txt b/q785KV5ZIN0.txt new file mode 100644 index 0000000000000000000000000000000000000000..113928ce1afa343fef8ae09fac41b1d1d0dbe29e --- /dev/null +++ b/q785KV5ZIN0.txt @@ -0,0 +1,1011 @@ +align:start position:0% + +Now we'd like to talk about angular + + align:start position:0% +Now we'd like to talk about angular + + + align:start position:0% +Now we'd like to talk about angular +velocity. So for a particle traveling in + + align:start position:0% +velocity. So for a particle traveling in + + + align:start position:0% +velocity. So for a particle traveling in +a circle, we've seen that the velocity + + align:start position:0% +a circle, we've seen that the velocity + + + align:start position:0% +a circle, we've seen that the velocity +can be written as r d theta + + align:start position:0% +can be written as r d theta + + + align:start position:0% +can be written as r d theta +dt in the theta hat + + align:start position:0% +dt in the theta hat + + + align:start position:0% +dt in the theta hat +direction. And we've also seen that d + + align:start position:0% +direction. And we've also seen that d + + + align:start position:0% +direction. And we've also seen that d +theta dt can be positive in which case + + align:start position:0% +theta dt can be positive in which case + + + align:start position:0% +theta dt can be positive in which case +theta is increasing. And so the particle + + align:start position:0% +theta is increasing. And so the particle + + + align:start position:0% +theta is increasing. And so the particle +is traveling around the circle in this + + align:start position:0% +is traveling around the circle in this + + + align:start position:0% +is traveling around the circle in this +direction. You can call that the + + align:start position:0% +direction. You can call that the + + + align:start position:0% +direction. You can call that the +counterclockwise direction. We've also + + align:start position:0% +counterclockwise direction. We've also + + + align:start position:0% +counterclockwise direction. We've also +seen that d theta dt can be negative in + + align:start position:0% +seen that d theta dt can be negative in + + + align:start position:0% +seen that d theta dt can be negative in +which case the angle is decreasing. So + + align:start position:0% +which case the angle is decreasing. So + + + align:start position:0% +which case the angle is decreasing. So +the particle is traveling around the + + align:start position:0% +the particle is traveling around the + + + align:start position:0% +the particle is traveling around the +circle in this direction which we could + + align:start position:0% +circle in this direction which we could + + + align:start position:0% +circle in this direction which we could +call + + align:start position:0% +call + + + align:start position:0% +call +clockwise. Let's now look at rotation in + + align:start position:0% +clockwise. Let's now look at rotation in + + + align:start position:0% +clockwise. Let's now look at rotation in +an arbitrary plane. So if I have a plane + + align:start position:0% +an arbitrary plane. So if I have a plane + + + align:start position:0% +an arbitrary plane. So if I have a plane +like this and I have some particle + + align:start position:0% +like this and I have some particle + + + align:start position:0% +like this and I have some particle +traveling in a circle like + + align:start position:0% +traveling in a circle like + + + align:start position:0% +traveling in a circle like +this and I have some observer that's + + align:start position:0% +this and I have some observer that's + + + align:start position:0% +this and I have some observer that's +above the plane looking down on this + + align:start position:0% +above the plane looking down on this + + + align:start position:0% +above the plane looking down on this +plane then it will see the uh this + + align:start position:0% +plane then it will see the uh this + + + align:start position:0% +plane then it will see the uh this +rotation as being in the + + align:start position:0% +rotation as being in the + + + align:start position:0% +rotation as being in the +counterclockwise direction. Whereas if I + + align:start position:0% +counterclockwise direction. Whereas if I + + + align:start position:0% +counterclockwise direction. Whereas if I +have another observer down + + align:start position:0% +have another observer down + + + align:start position:0% +have another observer down +here and they're looking up at this + + align:start position:0% +here and they're looking up at this + + + align:start position:0% +here and they're looking up at this +plane, they'll see the the motion as + + align:start position:0% +plane, they'll see the the motion as + + + align:start position:0% +plane, they'll see the the motion as +being clockwise. And so you can see we + + align:start position:0% +being clockwise. And so you can see we + + + align:start position:0% +being clockwise. And so you can see we +have a need for the more formal + + align:start position:0% +have a need for the more formal + + + align:start position:0% +have a need for the more formal +definition uh for the rotation of this. + + align:start position:0% +definition uh for the rotation of this. + + + align:start position:0% +definition uh for the rotation of this. +And so what we're going to do is use the + + align:start position:0% +And so what we're going to do is use the + + + align:start position:0% +And so what we're going to do is use the +right-h hand rule to define a direction + + align:start position:0% +right-h hand rule to define a direction + + + align:start position:0% +right-h hand rule to define a direction +that tells you both the direction. It + + align:start position:0% +that tells you both the direction. It + + + align:start position:0% +that tells you both the direction. It +defines the plane and it also tells you + + align:start position:0% +defines the plane and it also tells you + + + align:start position:0% +defines the plane and it also tells you +what the positive direction of rotation + + align:start position:0% +what the positive direction of rotation + + + align:start position:0% +what the positive direction of rotation +is for that plane. So the way we'll do + + align:start position:0% +is for that plane. So the way we'll do + + + align:start position:0% +is for that plane. So the way we'll do +this right hand rule is we'll take our + + align:start position:0% +this right hand rule is we'll take our + + + align:start position:0% +this right hand rule is we'll take our +right hand, we'll curl our fingers in + + align:start position:0% +right hand, we'll curl our fingers in + + + align:start position:0% +right hand, we'll curl our fingers in +the direction of the rotation and our + + align:start position:0% +the direction of the rotation and our + + + align:start position:0% +the direction of the rotation and our +thumb will point in the direction of + + align:start position:0% +thumb will point in the direction of + + + align:start position:0% +thumb will point in the direction of +that positive that the the positive + + align:start position:0% +that positive that the the positive + + + align:start position:0% +that positive that the the positive +direction that we're defining. So in + + align:start position:0% +direction that we're defining. So in + + + align:start position:0% +direction that we're defining. So in +this case I'm going to have an arrow + + align:start position:0% +this case I'm going to have an arrow + + + align:start position:0% +this case I'm going to have an arrow +like this. I'll call it n hat to + + align:start position:0% +like this. I'll call it n hat to + + + align:start position:0% +like this. I'll call it n hat to +indicate that it's the normal unit + + align:start position:0% +indicate that it's the normal unit + + + align:start position:0% +indicate that it's the normal unit +vector to that plane. + + align:start position:0% +vector to that plane. + + + align:start position:0% +vector to that plane. +All right, let's come back to this + + align:start position:0% +All right, let's come back to this + + + align:start position:0% +All right, let's come back to this +example now. Uh where the plane of the + + align:start position:0% +example now. Uh where the plane of the + + + align:start position:0% +example now. Uh where the plane of the +motion is this plane of the board. Uh + + align:start position:0% +motion is this plane of the board. Uh + + + align:start position:0% +motion is this plane of the board. Uh +and let's look at our two cases again. + + align:start position:0% +and let's look at our two cases again. + + + align:start position:0% +and let's look at our two cases again. +So in the case of d theta dt positive, + + align:start position:0% +So in the case of d theta dt positive, + + + align:start position:0% +So in the case of d theta dt positive, +our circle looks something like + + align:start position:0% +our circle looks something like + + + align:start position:0% +our circle looks something like +this. Um and you can see that if I use + + align:start position:0% +this. Um and you can see that if I use + + + align:start position:0% +this. Um and you can see that if I use +my right- hand + + align:start position:0% +my right- hand + + + align:start position:0% +my right- hand +rule, the plane the um the vector that + + align:start position:0% +rule, the plane the um the vector that + + + align:start position:0% +rule, the plane the um the vector that +I've defined is out of the board. And + + align:start position:0% +I've defined is out of the board. And + + + align:start position:0% +I've defined is out of the board. And +I'm going to use this symbol a circle + + align:start position:0% +I'm going to use this symbol a circle + + + align:start position:0% +I'm going to use this symbol a circle +with a dot to indicate this direction of + + align:start position:0% +with a dot to indicate this direction of + + + align:start position:0% +with a dot to indicate this direction of +out of the + + align:start position:0% +out of the + + + align:start position:0% +out of the +board. In our other case for d theta dt + + align:start position:0% +board. In our other case for d theta dt + + + align:start position:0% +board. In our other case for d theta dt +uh less than zero, our particle is + + align:start position:0% +uh less than zero, our particle is + + + align:start position:0% +uh less than zero, our particle is +traveling in this + + align:start position:0% +traveling in this + + + align:start position:0% +traveling in this +direction. And so you can see by my + + align:start position:0% +direction. And so you can see by my + + + align:start position:0% +direction. And so you can see by my +right-h hand rule that now the partic + + align:start position:0% +right-h hand rule that now the partic + + + align:start position:0% +right-h hand rule that now the partic +the that direction that I've defined is + + align:start position:0% +the that direction that I've defined is + + + align:start position:0% +the that direction that I've defined is +into the board. And for that I'm going + + align:start position:0% +into the board. And for that I'm going + + + align:start position:0% +into the board. And for that I'm going +to draw this as an x in a circle. So + + align:start position:0% +to draw this as an x in a circle. So + + + align:start position:0% +to draw this as an x in a circle. So +these are symbols that you'll see + + align:start position:0% +these are symbols that you'll see + + + align:start position:0% +these are symbols that you'll see +throughout the rest of the course. the + + align:start position:0% +throughout the rest of the course. the + + + align:start position:0% +throughout the rest of the course. the +in the uh out of the board and into the + + align:start position:0% +in the uh out of the board and into the + + + align:start position:0% +in the uh out of the board and into the +board + + align:start position:0% +board + + + align:start position:0% +board +symbols. Um and so now let's look back + + align:start position:0% +symbols. Um and so now let's look back + + + align:start position:0% +symbols. Um and so now let's look back +at our coordinate system that we've + + align:start position:0% +at our coordinate system that we've + + + align:start position:0% +at our coordinate system that we've +defined. We have an r hat direction and + + align:start position:0% +defined. We have an r hat direction and + + + align:start position:0% +defined. We have an r hat direction and +a theta hat direction. And in this + + align:start position:0% +a theta hat direction. And in this + + + align:start position:0% +a theta hat direction. And in this +coordinate system there's a third d + + align:start position:0% +coordinate system there's a third d + + + align:start position:0% +coordinate system there's a third d +direction that's defined which is the + + align:start position:0% +direction that's defined which is the + + + align:start position:0% +direction that's defined which is the +khat direction which you can see is out + + align:start position:0% +khat direction which you can see is out + + + align:start position:0% +khat direction which you can see is out +of the board. And so um now I'm going to + + align:start position:0% +of the board. And so um now I'm going to + + + align:start position:0% +of the board. And so um now I'm going to +define what we actually call the angular + + align:start position:0% +define what we actually call the angular + + + align:start position:0% +define what we actually call the angular +velocity as omega and I'm going to write + + align:start position:0% +velocity as omega and I'm going to write + + + align:start position:0% +velocity as omega and I'm going to write +that as d theta + + align:start position:0% +that as d theta + + + align:start position:0% +that as d theta +dt now in the k hat direction in this + + align:start position:0% +dt now in the k hat direction in this + + + align:start position:0% +dt now in the k hat direction in this +case. Uh it could be in an arbitrary + + align:start position:0% +case. Uh it could be in an arbitrary + + + align:start position:0% +case. Uh it could be in an arbitrary +nhat direction depending on what your + + align:start position:0% +nhat direction depending on what your + + + align:start position:0% +nhat direction depending on what your +plane of motion is. In this case I'm + + align:start position:0% +plane of motion is. In this case I'm + + + align:start position:0% +plane of motion is. In this case I'm +going to call it in the khat direction. + + align:start position:0% +going to call it in the khat direction. + + + align:start position:0% +going to call it in the khat direction. +And now you can see that um these signs + + align:start position:0% +And now you can see that um these signs + + + align:start position:0% +And now you can see that um these signs +are going to line up with uh these + + align:start position:0% +are going to line up with uh these + + + align:start position:0% +are going to line up with uh these +directions. So omega as d theta dt khat + + align:start position:0% +directions. So omega as d theta dt khat + + + align:start position:0% +directions. So omega as d theta dt khat +when d theta dt is positive khat is in + + align:start position:0% +when d theta dt is positive khat is in + + + align:start position:0% +when d theta dt is positive khat is in +the same direction as this unit normal + + align:start position:0% +the same direction as this unit normal + + + align:start position:0% +the same direction as this unit normal +that we've defined that defines both the + + align:start position:0% +that we've defined that defines both the + + + align:start position:0% +that we've defined that defines both the +plane of the motion and the direction of + + align:start position:0% +plane of the motion and the direction of + + + align:start position:0% +plane of the motion and the direction of +the motion and when d theta dt is + + align:start position:0% +the motion and when d theta dt is + + + align:start position:0% +the motion and when d theta dt is +negative I have that omega is in the + + align:start position:0% +negative I have that omega is in the + + + align:start position:0% +negative I have that omega is in the +negative khat direction which is exactly + + align:start position:0% +negative khat direction which is exactly + + + align:start position:0% +negative khat direction which is exactly +this direction here that we've defined + + align:start position:0% +this direction here that we've defined + + + align:start position:0% +this direction here that we've defined +as being the motion for this plane and + + align:start position:0% +as being the motion for this plane and + + + align:start position:0% +as being the motion for this plane and +so this is how we define angular + + align:start position:0% +so this is how we define angular + + + align:start position:0% +so this is how we define angular +velocity + + align:start position:0% +velocity + + + align:start position:0% +velocity +So we can define the comp d theta dt to + + align:start position:0% +So we can define the comp d theta dt to + + + align:start position:0% +So we can define the comp d theta dt to +be the component of the angular velocity + + align:start position:0% +be the component of the angular velocity + + + align:start position:0% +be the component of the angular velocity +omega z because it's in the khat + + align:start position:0% +omega z because it's in the khat + + + align:start position:0% +omega z because it's in the khat +direction and we can also define the + + align:start position:0% +direction and we can also define the + + + align:start position:0% +direction and we can also define the +angular speed which we write as just + + align:start position:0% +angular speed which we write as just + + + align:start position:0% +angular speed which we write as just +omega as being the absolute value of + + align:start position:0% +omega as being the absolute value of + + + align:start position:0% +omega as being the absolute value of +this angular velocity omega. So that is + + align:start position:0% +this angular velocity omega. So that is + + + align:start position:0% +this angular velocity omega. So that is +in other words it's just the absolute + + align:start position:0% +in other words it's just the absolute + + + align:start position:0% +in other words it's just the absolute +value of d theta + + align:start position:0% +value of d theta + + + align:start position:0% +value of d theta +dt. So when a particle is undergoing + + align:start position:0% +dt. So when a particle is undergoing + + + align:start position:0% +dt. So when a particle is undergoing +circular motion, it has a velocity that + + align:start position:0% +circular motion, it has a velocity that + + + align:start position:0% +circular motion, it has a velocity that +you can describe which is the tangential + + align:start position:0% +you can describe which is the tangential + + + align:start position:0% +you can describe which is the tangential +uh motion around the circle and it's + + align:start position:0% +uh motion around the circle and it's + + + align:start position:0% +uh motion around the circle and it's +also it also has an angular velocity + + align:start position:0% +also it also has an angular velocity + + + align:start position:0% +also it also has an angular velocity +which we define as being in a direction + + align:start position:0% +which we define as being in a direction + + + align:start position:0% +which we define as being in a direction +that's perpendicular to that direction + + align:start position:0% +that's perpendicular to that direction + + + align:start position:0% +that's perpendicular to that direction +of uh rotation and it's defined by the + + align:start position:0% +of uh rotation and it's defined by the + + + align:start position:0% +of uh rotation and it's defined by the +right- hand rule. And now that we have + + align:start position:0% +right- hand rule. And now that we have + + + align:start position:0% +right- hand rule. And now that we have +defined this omega z the angular comp + + align:start position:0% +defined this omega z the angular comp + + + align:start position:0% +defined this omega z the angular comp +the component of the angular velocity we + + align:start position:0% +the component of the angular velocity we + + + align:start position:0% +the component of the angular velocity we +can rewrite the velocity as just being + + align:start position:0% +can rewrite the velocity as just being + + + align:start position:0% +can rewrite the velocity as just being +equal to r * omega z still in that theta + + align:start position:0% +equal to r * omega z still in that theta + + + align:start position:0% +equal to r * omega z still in that theta +hat direction. And so this is another + + align:start position:0% +hat direction. And so this is another + + + align:start position:0% +hat direction. And so this is another +way that we can write the velocity and + + align:start position:0% +way that we can write the velocity and + + + align:start position:0% +way that we can write the velocity and +connect it back to the angular velocity. \ No newline at end of file diff --git a/qM-X1L3Sjsc.txt b/qM-X1L3Sjsc.txt new file mode 100644 index 0000000000000000000000000000000000000000..dceaa4652f875af650fcba9fe0274084013b0046 --- /dev/null +++ b/qM-X1L3Sjsc.txt @@ -0,0 +1,7971 @@ +align:start position:0% + +Hi, my name is Bob Metaf and I'm here + + align:start position:0% +Hi, my name is Bob Metaf and I'm here + + + align:start position:0% +Hi, my name is Bob Metaf and I'm here +today to talk about the next big thing, + + align:start position:0% +today to talk about the next big thing, + + + align:start position:0% +today to talk about the next big thing, +the video + + align:start position:0% +the video + + + align:start position:0% +the video +internet. Uh, now I'm not sure what kind + + align:start position:0% +internet. Uh, now I'm not sure what kind + + + align:start position:0% +internet. Uh, now I'm not sure what kind +of video we're talking about and I'm not + + align:start position:0% +of video we're talking about and I'm not + + + align:start position:0% +of video we're talking about and I'm not +sure if it'll actually be the internet + + align:start position:0% +sure if it'll actually be the internet + + + align:start position:0% +sure if it'll actually be the internet +when we're all done, but nonetheless, + + align:start position:0% +when we're all done, but nonetheless, + + + align:start position:0% +when we're all done, but nonetheless, +I'm going to call this the next big + + align:start position:0% +I'm going to call this the next big + + + align:start position:0% +I'm going to call this the next big +thing, the video internet. And one of + + align:start position:0% +thing, the video internet. And one of + + + align:start position:0% +thing, the video internet. And one of +the questions which I hope to get to in + + align:start position:0% +the questions which I hope to get to in + + + align:start position:0% +the questions which I hope to get to in +a few minutes is whether in driving the + + align:start position:0% +a few minutes is whether in driving the + + + align:start position:0% +a few minutes is whether in driving the +proliferation of the video internet uh + + align:start position:0% +proliferation of the video internet uh + + + align:start position:0% +proliferation of the video internet uh +whether that'll be driven by + + align:start position:0% +whether that'll be driven by + + + align:start position:0% +whether that'll be driven by +communication or content or + + align:start position:0% +communication or content or + + + align:start position:0% +communication or content or +commerce. Let's begin with a short + + align:start position:0% +commerce. Let's begin with a short + + + align:start position:0% +commerce. Let's begin with a short +history of + + align:start position:0% +history of + + + align:start position:0% +history of +networking. In the beginning there was + + align:start position:0% +networking. In the beginning there was + + + align:start position:0% +networking. In the beginning there was +mail the US mail say and it's still with + + align:start position:0% +mail the US mail say and it's still with + + + align:start position:0% +mail the US mail say and it's still with +us. And what came later in the 19th + + align:start position:0% +us. And what came later in the 19th + + + align:start position:0% +us. And what came later in the 19th +century was uh TX the uh carrying of + + align:start position:0% +century was uh TX the uh carrying of + + + align:start position:0% +century was uh TX the uh carrying of +mail certain forms of mail + + align:start position:0% +mail certain forms of mail + + + align:start position:0% +mail certain forms of mail +electronically through the TX network. + + align:start position:0% +electronically through the TX network. + + + align:start position:0% +electronically through the TX network. +And then TX was generally overtaken by a + + align:start position:0% +And then TX was generally overtaken by a + + + align:start position:0% +And then TX was generally overtaken by a +new electronic network called the + + align:start position:0% +new electronic network called the + + + align:start position:0% +new electronic network called the +telephone network which of course is + + align:start position:0% +telephone network which of course is + + + align:start position:0% +telephone network which of course is +still with us. uh the telephone being uh + + align:start position:0% +still with us. uh the telephone being uh + + + align:start position:0% +still with us. uh the telephone being uh +as you well know a two-way communication + + align:start position:0% +as you well know a two-way communication + + + align:start position:0% +as you well know a two-way communication +system generally paid for by uh + + align:start position:0% +system generally paid for by uh + + + align:start position:0% +system generally paid for by uh +subscriptions and its principal use + + align:start position:0% +subscriptions and its principal use + + + align:start position:0% +subscriptions and its principal use +being communication among people. The + + align:start position:0% +being communication among people. The + + + align:start position:0% +being communication among people. The +next network after that was a television + + align:start position:0% +next network after that was a television + + + align:start position:0% +next network after that was a television +network which uh arose during my + + align:start position:0% +network which uh arose during my + + + align:start position:0% +network which uh arose during my +lifetime. Uh and television as you know + + align:start position:0% +lifetime. Uh and television as you know + + + align:start position:0% +lifetime. Uh and television as you know +is uh one way and generally + + align:start position:0% +is uh one way and generally + + + align:start position:0% +is uh one way and generally +entertainmentoriented and paid for + + align:start position:0% +entertainmentoriented and paid for + + + align:start position:0% +entertainmentoriented and paid for +through advertising although + + align:start position:0% +through advertising although + + + align:start position:0% +through advertising although +increasingly by subscriptions now with + + align:start position:0% +increasingly by subscriptions now with + + + align:start position:0% +increasingly by subscriptions now with +cable television. And finally the + + align:start position:0% +cable television. And finally the + + + align:start position:0% +cable television. And finally the +current big thing the internet which uh + + align:start position:0% +current big thing the internet which uh + + + align:start position:0% +current big thing the internet which uh +came to us starting in + + align:start position:0% +came to us starting in + + + align:start position:0% +came to us starting in +1969. Now the internet itself has been a + + align:start position:0% +1969. Now the internet itself has been a + + + align:start position:0% +1969. Now the internet itself has been a +series of applications since 1969. + + align:start position:0% +series of applications since 1969. + + + align:start position:0% +series of applications since 1969. +The people who first started building + + align:start position:0% +The people who first started building + + + align:start position:0% +The people who first started building +the internet uh thought that it would be + + align:start position:0% +the internet uh thought that it would be + + + align:start position:0% +the internet uh thought that it would be +used uh with dumb terminals logging into + + align:start position:0% +used uh with dumb terminals logging into + + + align:start position:0% +used uh with dumb terminals logging into +remote computers across the country. And + + align:start position:0% +remote computers across the country. And + + + align:start position:0% +remote computers across the country. And +that was the first application built to + + align:start position:0% +that was the first application built to + + + align:start position:0% +that was the first application built to +run on the early internet. Uh and + + align:start position:0% +run on the early internet. Uh and + + + align:start position:0% +run on the early internet. Uh and +shortly after that it was realized that + + align:start position:0% +shortly after that it was realized that + + + align:start position:0% +shortly after that it was realized that +in order to run remote computer + + align:start position:0% +in order to run remote computer + + + align:start position:0% +in order to run remote computer +applications at large computers across + + align:start position:0% +applications at large computers across + + + align:start position:0% +applications at large computers across +the country, you'd have to transfer your + + align:start position:0% +the country, you'd have to transfer your + + + align:start position:0% +the country, you'd have to transfer your +data there. You'd have to transfer + + align:start position:0% +data there. You'd have to transfer + + + align:start position:0% +data there. You'd have to transfer +files. So the file transfer protocol + + align:start position:0% +files. So the file transfer protocol + + + align:start position:0% +files. So the file transfer protocol +arose. And then shortly after that a + + align:start position:0% +arose. And then shortly after that a + + + align:start position:0% +arose. And then shortly after that a +certain kind of file became very + + align:start position:0% +certain kind of file became very + + + align:start position:0% +certain kind of file became very +important and that file was the + + align:start position:0% +important and that file was the + + + align:start position:0% +important and that file was the +electronic message. And so suddenly in + + align:start position:0% +electronic message. And so suddenly in + + + align:start position:0% +electronic message. And so suddenly in +about + + align:start position:0% +about + + + align:start position:0% +about +1971 we had email and email was pretty + + align:start position:0% +1971 we had email and email was pretty + + + align:start position:0% +1971 we had email and email was pretty +much the major use of the internet for + + align:start position:0% +much the major use of the internet for + + + align:start position:0% +much the major use of the internet for +the next 20 years. And dur now during + + align:start position:0% +the next 20 years. And dur now during + + + align:start position:0% +the next 20 years. And dur now during +that time uh a new kind of structure + + align:start position:0% +that time uh a new kind of structure + + + align:start position:0% +that time uh a new kind of structure +arose called news groups. That is where + + align:start position:0% +arose called news groups. That is where + + + align:start position:0% +arose called news groups. That is where +computers on the net would be used to + + align:start position:0% +computers on the net would be used to + + + align:start position:0% +computers on the net would be used to +collect emails and keep them so that uh + + align:start position:0% +collect emails and keep them so that uh + + + align:start position:0% +collect emails and keep them so that uh +other people might view a conversation + + align:start position:0% +other people might view a conversation + + + align:start position:0% +other people might view a conversation +conducted in email and these would be + + align:start position:0% +conducted in email and these would be + + + align:start position:0% +conducted in email and these would be +categorized by topics. So remote login + + align:start position:0% +categorized by topics. So remote login + + + align:start position:0% +categorized by topics. So remote login +and file transfer and electronic mail + + align:start position:0% +and file transfer and electronic mail + + + align:start position:0% +and file transfer and electronic mail +and news groups were pretty much what + + align:start position:0% +and news groups were pretty much what + + + align:start position:0% +and news groups were pretty much what +the internet was used for until the + + align:start position:0% +the internet was used for until the + + + align:start position:0% +the internet was used for until the +1990s. And uh starting in about 1990 we + + align:start position:0% +1990s. And uh starting in about 1990 we + + + align:start position:0% +1990s. And uh starting in about 1990 we +uh learned about the worldwide web. And + + align:start position:0% +uh learned about the worldwide web. And + + + align:start position:0% +uh learned about the worldwide web. And +the first form of that in the early 90s + + align:start position:0% +the first form of that in the early 90s + + + align:start position:0% +the first form of that in the early 90s +was uh the arrival of web publishing, + + align:start position:0% +was uh the arrival of web publishing, + + + align:start position:0% +was uh the arrival of web publishing, +the use of the internet for publishing + + align:start position:0% +the use of the internet for publishing + + + align:start position:0% +the use of the internet for publishing +information. And + + align:start position:0% +information. And + + + align:start position:0% +information. And +uh a stunning conclusion from that + + align:start position:0% +uh a stunning conclusion from that + + + align:start position:0% +uh a stunning conclusion from that +arrival was the recognition among + + align:start position:0% +arrival was the recognition among + + + align:start position:0% +arrival was the recognition among +journalists, publishers that there's a + + align:start position:0% +journalists, publishers that there's a + + + align:start position:0% +journalists, publishers that there's a +new there was a new kind of content + + align:start position:0% +new there was a new kind of content + + + align:start position:0% +new there was a new kind of content +suddenly. Uh prior to web publishing, + + align:start position:0% +suddenly. Uh prior to web publishing, + + + align:start position:0% +suddenly. Uh prior to web publishing, +generally speaking, there were two kinds + + align:start position:0% +generally speaking, there were two kinds + + + align:start position:0% +generally speaking, there were two kinds +of content. There was editorial and + + align:start position:0% +of content. There was editorial and + + + align:start position:0% +of content. There was editorial and +there was advertising. And the whole + + align:start position:0% +there was advertising. And the whole + + + align:start position:0% +there was advertising. And the whole +publishing industry was uh very careful + + align:start position:0% +publishing industry was uh very careful + + + align:start position:0% +publishing industry was uh very careful +to keep to keep those well some were + + align:start position:0% +to keep to keep those well some were + + + align:start position:0% +to keep to keep those well some were +very careful to keep those separate and + + align:start position:0% +very careful to keep those separate and + + + align:start position:0% +very careful to keep those separate and +how they would be managed. It was called + + align:start position:0% +how they would be managed. It was called + + + align:start position:0% +how they would be managed. It was called +the separation of church and state. But + + align:start position:0% +the separation of church and state. But + + + align:start position:0% +the separation of church and state. But +when we began publishing on the + + align:start position:0% +when we began publishing on the + + + align:start position:0% +when we began publishing on the +internet, we discovered a new kind of + + align:start position:0% +internet, we discovered a new kind of + + + align:start position:0% +internet, we discovered a new kind of +content which I'll call community + + align:start position:0% +content which I'll call community + + + align:start position:0% +content which I'll call community +content. That is content which was not + + align:start position:0% +content. That is content which was not + + + align:start position:0% +content. That is content which was not +produced by the editors of the + + align:start position:0% +produced by the editors of the + + + align:start position:0% +produced by the editors of the +publication and not produced by the + + align:start position:0% +publication and not produced by the + + + align:start position:0% +publication and not produced by the +advertisers of the publication but + + align:start position:0% +advertisers of the publication but + + + align:start position:0% +advertisers of the publication but +produced by the readers of the + + align:start position:0% +produced by the readers of the + + + align:start position:0% +produced by the readers of the +publication. So now on the internet, I + + align:start position:0% +publication. So now on the internet, I + + + align:start position:0% +publication. So now on the internet, I +think there are three kinds of content. + + align:start position:0% +think there are three kinds of content. + + + align:start position:0% +think there are three kinds of content. +They're all important and community + + align:start position:0% +They're all important and community + + + align:start position:0% +They're all important and community +content is the new one. Toward the + + align:start position:0% +content is the new one. Toward the + + + align:start position:0% +content is the new one. Toward the +mid90s, the web then went from + + align:start position:0% +mid90s, the web then went from + + + align:start position:0% +mid90s, the web then went from +publishing into commerce. And what we + + align:start position:0% +publishing into commerce. And what we + + + align:start position:0% +publishing into commerce. And what we +saw there was the the dot bubble, which + + align:start position:0% +saw there was the the dot bubble, which + + + align:start position:0% +saw there was the the dot bubble, which +has only recently burst. Not that web + + align:start position:0% +has only recently burst. Not that web + + + align:start position:0% +has only recently burst. Not that web +commerce is going away, but that there + + align:start position:0% +commerce is going away, but that there + + + align:start position:0% +commerce is going away, but that there +was there's been a recent correction + + align:start position:0% +was there's been a recent correction + + + align:start position:0% +was there's been a recent correction +from which we'll soon recover. So, + + align:start position:0% +from which we'll soon recover. So, + + + align:start position:0% +from which we'll soon recover. So, +what's the next big thing after the.com + + align:start position:0% +what's the next big thing after the.com + + + align:start position:0% +what's the next big thing after the.com +bubble has burst, after uh web commerce? + + align:start position:0% +bubble has burst, after uh web commerce? + + + align:start position:0% +bubble has burst, after uh web commerce? +Uh, and and mind you, email's not going + + align:start position:0% +Uh, and and mind you, email's not going + + + align:start position:0% +Uh, and and mind you, email's not going +away and FTP is not going away and web + + align:start position:0% +away and FTP is not going away and web + + + align:start position:0% +away and FTP is not going away and web +publishing is not going away and web + + align:start position:0% +publishing is not going away and web + + + align:start position:0% +publishing is not going away and web +commerce is not going away. They're all + + align:start position:0% +commerce is not going away. They're all + + + align:start position:0% +commerce is not going away. They're all +with us like the US mail. But what's the + + align:start position:0% +with us like the US mail. But what's the + + + align:start position:0% +with us like the US mail. But what's the +next big thing? The next thing that will + + align:start position:0% +next big thing? The next thing that will + + + align:start position:0% +next big thing? The next thing that will +drive proliferation of the internet and + + align:start position:0% +drive proliferation of the internet and + + + align:start position:0% +drive proliferation of the internet and +electronic networking and I think it's + + align:start position:0% +electronic networking and I think it's + + + align:start position:0% +electronic networking and I think it's +the convergence of the web with the + + align:start position:0% +the convergence of the web with the + + + align:start position:0% +the convergence of the web with the +pre-existing voice and video uh + + align:start position:0% +pre-existing voice and video uh + + + align:start position:0% +pre-existing voice and video uh +networks. the uh convergence of the + + align:start position:0% +networks. the uh convergence of the + + + align:start position:0% +networks. the uh convergence of the +internet, the telephone and the + + align:start position:0% +internet, the telephone and the + + + align:start position:0% +internet, the telephone and the +television + + align:start position:0% + + + + align:start position:0% + +networks. So let's talk about + + align:start position:0% +networks. So let's talk about + + + align:start position:0% +networks. So let's talk about +convergence, the convergence of the + + align:start position:0% +convergence, the convergence of the + + + align:start position:0% +convergence, the convergence of the +internet, telephone and television + + align:start position:0% +internet, telephone and television + + + align:start position:0% +internet, telephone and television +networks. This is not an entirely new + + align:start position:0% +networks. This is not an entirely new + + + align:start position:0% +networks. This is not an entirely new +process. It's been going on for some + + align:start position:0% +process. It's been going on for some + + + align:start position:0% +process. It's been going on for some +years. In fact, we have some information + + align:start position:0% +years. In fact, we have some information + + + align:start position:0% +years. In fact, we have some information +which I'm about to share with you about + + align:start position:0% +which I'm about to share with you about + + + align:start position:0% +which I'm about to share with you about +the recent history of convergence. So we + + align:start position:0% +the recent history of convergence. So we + + + align:start position:0% +the recent history of convergence. So we +have these three communities of + + align:start position:0% +have these three communities of + + + align:start position:0% +have these three communities of +interest. We have the internet people, + + align:start position:0% +interest. We have the internet people, + + + align:start position:0% +interest. We have the internet people, +my people. We have the telephone people + + align:start position:0% +my people. We have the telephone people + + + align:start position:0% +my people. We have the telephone people +and we have the television people. All + + align:start position:0% +and we have the television people. All + + + align:start position:0% +and we have the television people. All +of whom saw convergence. The notion that + + align:start position:0% +of whom saw convergence. The notion that + + + align:start position:0% +of whom saw convergence. The notion that +the internet and telephone and + + align:start position:0% +the internet and telephone and + + + align:start position:0% +the internet and telephone and +television networks might converge. And + + align:start position:0% +television networks might converge. And + + + align:start position:0% +television networks might converge. And +they all approached this convergent with + + align:start position:0% +they all approached this convergent with + + + align:start position:0% +they all approached this convergent with +certain goals in mind. And what I'd like + + align:start position:0% +certain goals in mind. And what I'd like + + + align:start position:0% +certain goals in mind. And what I'd like +to now summarize is what I my view of + + align:start position:0% +to now summarize is what I my view of + + + align:start position:0% +to now summarize is what I my view of +what they wanted when they approached + + align:start position:0% +what they wanted when they approached + + + align:start position:0% +what they wanted when they approached +convergence and what recently they got + + align:start position:0% +convergence and what recently they got + + + align:start position:0% +convergence and what recently they got +which was quite different from what they + + align:start position:0% +which was quite different from what they + + + align:start position:0% +which was quite different from what they +wanted. Let's begin with the internet + + align:start position:0% +wanted. Let's begin with the internet + + + align:start position:0% +wanted. Let's begin with the internet +people. The internet people wanted + + align:start position:0% +people. The internet people wanted + + + align:start position:0% +people. The internet people wanted +convergence with the telephone and later + + align:start position:0% +convergence with the telephone and later + + + align:start position:0% +convergence with the telephone and later +television networks because they wanted + + align:start position:0% +television networks because they wanted + + + align:start position:0% +television networks because they wanted +ubiquity. They had built this wonderful + + align:start position:0% +ubiquity. They had built this wonderful + + + align:start position:0% +ubiquity. They had built this wonderful +thing the internet and they believed as + + align:start position:0% +thing the internet and they believed as + + + align:start position:0% +thing the internet and they believed as +I do that we wanted everyone to have it + + align:start position:0% +I do that we wanted everyone to have it + + + align:start position:0% +I do that we wanted everyone to have it +and to use it and and convergence was a + + align:start position:0% +and to use it and and convergence was a + + + align:start position:0% +and to use it and and convergence was a +way of getting there because the + + align:start position:0% +way of getting there because the + + + align:start position:0% +way of getting there because the +telephone network is ubiquitous and the + + align:start position:0% +telephone network is ubiquitous and the + + + align:start position:0% +telephone network is ubiquitous and the +television network is ubiquitous. So if + + align:start position:0% +television network is ubiquitous. So if + + + align:start position:0% +television network is ubiquitous. So if +only the internet could be put on the + + align:start position:0% +only the internet could be put on the + + + align:start position:0% +only the internet could be put on the +telephone and television networks, this + + align:start position:0% +telephone and television networks, this + + + align:start position:0% +telephone and television networks, this +great thing that we internet people + + align:start position:0% +great thing that we internet people + + + align:start position:0% +great thing that we internet people +brought to the world would then be + + align:start position:0% +brought to the world would then be + + + align:start position:0% +brought to the world would then be +available to everyone. What a great + + align:start position:0% +available to everyone. What a great + + + align:start position:0% +available to everyone. What a great +goal. And so we began moving the + + align:start position:0% +goal. And so we began moving the + + + align:start position:0% +goal. And so we began moving the +internet on initially onto the telephone + + align:start position:0% +internet on initially onto the telephone + + + align:start position:0% +internet on initially onto the telephone +network. And in in fact today most + + align:start position:0% +network. And in in fact today most + + + align:start position:0% +network. And in in fact today most +people more than 90% of the people who + + align:start position:0% +people more than 90% of the people who + + + align:start position:0% +people more than 90% of the people who +use the internet use it through a dialup + + align:start position:0% +use the internet use it through a dialup + + + align:start position:0% +use the internet use it through a dialup +telephone + + align:start position:0% + + + + align:start position:0% + +modem. But the internet people got + + align:start position:0% +modem. But the internet people got + + + align:start position:0% +modem. But the internet people got +something different, something + + align:start position:0% +something different, something + + + align:start position:0% +something different, something +unexpected that they didn't quite want. + + align:start position:0% +unexpected that they didn't quite want. + + + align:start position:0% +unexpected that they didn't quite want. +For example, when you let a lot of + + align:start position:0% +For example, when you let a lot of + + + align:start position:0% +For example, when you let a lot of +people onto the network who are not uh + + align:start position:0% +people onto the network who are not uh + + + align:start position:0% +people onto the network who are not uh +university PhDs is you get what's called + + align:start position:0% +university PhDs is you get what's called + + + align:start position:0% +university PhDs is you get what's called +newbies. These are people who weren't um + + align:start position:0% +newbies. These are people who weren't um + + + align:start position:0% +newbies. These are people who weren't um +uh brought up properly in the ways of + + align:start position:0% +uh brought up properly in the ways of + + + align:start position:0% +uh brought up properly in the ways of +the internet and had different interests + + align:start position:0% +the internet and had different interests + + + align:start position:0% +the internet and had different interests +and different values and when they came + + align:start position:0% +and different values and when they came + + + align:start position:0% +and different values and when they came +and they didn't know how to use the + + align:start position:0% +and they didn't know how to use the + + + align:start position:0% +and they didn't know how to use the +internet all that well and this was + + align:start position:0% +internet all that well and this was + + + align:start position:0% +internet all that well and this was +infuriating to the internet + + align:start position:0% +infuriating to the internet + + + align:start position:0% +infuriating to the internet +intelligencia. The second thing they got + + align:start position:0% +intelligencia. The second thing they got + + + align:start position:0% +intelligencia. The second thing they got +was slows. The telephone network was not + + align:start position:0% +was slows. The telephone network was not + + + align:start position:0% +was slows. The telephone network was not +designed to carry high-speed data. It + + align:start position:0% +designed to carry high-speed data. It + + + align:start position:0% +designed to carry high-speed data. It +was designed to carry voice + + align:start position:0% +was designed to carry voice + + + align:start position:0% +was designed to carry voice +communications. And so all these people + + align:start position:0% +communications. And so all these people + + + align:start position:0% +communications. And so all these people +who are accessing the internet through + + align:start position:0% +who are accessing the internet through + + + align:start position:0% +who are accessing the internet through +their dialup telephone modems are doing + + align:start position:0% +their dialup telephone modems are doing + + + align:start position:0% +their dialup telephone modems are doing +so slowly. And this is really painful. + + align:start position:0% +so slowly. And this is really painful. + + + align:start position:0% +so slowly. And this is really painful. +And so we're all in a big rush to uh + + align:start position:0% +And so we're all in a big rush to uh + + + align:start position:0% +And so we're all in a big rush to uh +solve that + + align:start position:0% +solve that + + + align:start position:0% +solve that +problem. The telephone people saw great + + align:start position:0% +problem. The telephone people saw great + + + align:start position:0% +problem. The telephone people saw great +promise in convergence too. And they + + align:start position:0% +promise in convergence too. And they + + + align:start position:0% +promise in convergence too. And they +were kind of interested in convergence + + align:start position:0% +were kind of interested in convergence + + + align:start position:0% +were kind of interested in convergence +because what they heard was the internet + + align:start position:0% +because what they heard was the internet + + + align:start position:0% +because what they heard was the internet +is a worldwide network and people use it + + align:start position:0% +is a worldwide network and people use it + + + align:start position:0% +is a worldwide network and people use it +a lot. So the telephone people said + + align:start position:0% +a lot. So the telephone people said + + + align:start position:0% +a lot. So the telephone people said +we're going to get a lot of longd + + align:start position:0% +we're going to get a lot of longd + + + align:start position:0% +we're going to get a lot of longd +distanceance minutes out of this. People + + align:start position:0% +distanceance minutes out of this. People + + + align:start position:0% +distanceance minutes out of this. People +are going to be dialing into that + + align:start position:0% +are going to be dialing into that + + + align:start position:0% +are going to be dialing into that +internet around the world and we're + + align:start position:0% +internet around the world and we're + + + align:start position:0% +internet around the world and we're +going to bill them minute by minute for + + align:start position:0% +going to bill them minute by minute for + + + align:start position:0% +going to bill them minute by minute for +uh their use of the internet. And what a + + align:start position:0% +uh their use of the internet. And what a + + + align:start position:0% +uh their use of the internet. And what a +great new business opportunity this is. + + align:start position:0% +great new business opportunity this is. + + + align:start position:0% +great new business opportunity this is. +They thought what they got the telephone + + align:start position:0% +They thought what they got the telephone + + + align:start position:0% +They thought what they got the telephone +people they got something completely + + align:start position:0% +people they got something completely + + + align:start position:0% +people they got something completely +different. They got a lot of short + + align:start position:0% +different. They got a lot of short + + + align:start position:0% +different. They got a lot of short +distance hours. That is instead of + + align:start position:0% +distance hours. That is instead of + + + align:start position:0% +distance hours. That is instead of +long-distance minutes they got short + + align:start position:0% +long-distance minutes they got short + + + align:start position:0% +long-distance minutes they got short +distance. And people instead of dialing + + align:start position:0% +distance. And people instead of dialing + + + align:start position:0% +distance. And people instead of dialing +around the world to access the internet + + align:start position:0% +around the world to access the internet + + + align:start position:0% +around the world to access the internet +just dialed an internet access port in + + align:start position:0% +just dialed an internet access port in + + + align:start position:0% +just dialed an internet access port in +their hometown on the same exchange. And + + align:start position:0% +their hometown on the same exchange. And + + + align:start position:0% +their hometown on the same exchange. And +instead of being on there for a minute + + align:start position:0% +instead of being on there for a minute + + + align:start position:0% +instead of being on there for a minute +or two or three, which is how the + + align:start position:0% +or two or three, which is how the + + + align:start position:0% +or two or three, which is how the +telephone network was designed, they + + align:start position:0% +telephone network was designed, they + + + align:start position:0% +telephone network was designed, they +used it for hours, if not 24 hours a + + align:start position:0% +used it for hours, if not 24 hours a + + + align:start position:0% +used it for hours, if not 24 hours a +day. And the telephone companies were + + align:start position:0% +day. And the telephone companies were + + + align:start position:0% +day. And the telephone companies were +technically unprepared to take on this + + align:start position:0% +technically unprepared to take on this + + + align:start position:0% +technically unprepared to take on this +load. And they had no way of billing for + + align:start position:0% +load. And they had no way of billing for + + + align:start position:0% +load. And they had no way of billing for +it because year for years and years and + + align:start position:0% +it because year for years and years and + + + align:start position:0% +it because year for years and years and +years, they've been organized around + + align:start position:0% +years, they've been organized around + + + align:start position:0% +years, they've been organized around +collecting money for long distance, not + + align:start position:0% +collecting money for long distance, not + + + align:start position:0% +collecting money for long distance, not +short + + align:start position:0% +short + + + align:start position:0% +short +distance. So this was a bit of a jolt + + align:start position:0% +distance. So this was a bit of a jolt + + + align:start position:0% +distance. So this was a bit of a jolt +and a surprise and made them angry about + + align:start position:0% +and a surprise and made them angry about + + + align:start position:0% +and a surprise and made them angry about +this convergence. Then something even + + align:start position:0% +this convergence. Then something even + + + align:start position:0% +this convergence. Then something even +worse happened. People started talking + + align:start position:0% +worse happened. People started talking + + + align:start position:0% +worse happened. People started talking +about using the internet to carry voice + + align:start position:0% +about using the internet to carry voice + + + align:start position:0% +about using the internet to carry voice +conversations for free. And the + + align:start position:0% +conversations for free. And the + + + align:start position:0% +conversations for free. And the +telephone companies uh in the United + + align:start position:0% +telephone companies uh in the United + + + align:start position:0% +telephone companies uh in the United +States uh generate about $200 billion a + + align:start position:0% +States uh generate about $200 billion a + + + align:start position:0% +States uh generate about $200 billion a +year in carrying longd distanceance + + align:start position:0% +year in carrying longd distanceance + + + align:start position:0% +year in carrying longd distanceance +telephone conversations. And the thought + + align:start position:0% +telephone conversations. And the thought + + + align:start position:0% +telephone conversations. And the thought +that these conversations might be + + align:start position:0% +that these conversations might be + + + align:start position:0% +that these conversations might be +carried for free over the internet was + + align:start position:0% +carried for free over the internet was + + + align:start position:0% +carried for free over the internet was +quite shocking to them. Now, of course, + + align:start position:0% +quite shocking to them. Now, of course, + + + align:start position:0% +quite shocking to them. Now, of course, +free is a very low price and uh they're + + align:start position:0% +free is a very low price and uh they're + + + align:start position:0% +free is a very low price and uh they're +not likely to be free, but the threat of + + align:start position:0% +not likely to be free, but the threat of + + + align:start position:0% +not likely to be free, but the threat of +voice over the internet has been um very + + align:start position:0% +voice over the internet has been um very + + + align:start position:0% +voice over the internet has been um very +motivating to the telephone companies. + + align:start position:0% +motivating to the telephone companies. + + + align:start position:0% +motivating to the telephone companies. +They're not sure they want to do + + align:start position:0% +They're not sure they want to do + + + align:start position:0% +They're not sure they want to do +convergence all that much + + align:start position:0% +convergence all that much + + + align:start position:0% +convergence all that much +anymore. The television community, the + + align:start position:0% +anymore. The television community, the + + + align:start position:0% +anymore. The television community, the +television networking people also saw + + align:start position:0% +television networking people also saw + + + align:start position:0% +television networking people also saw +promise in convergence. Uh for years and + + align:start position:0% +promise in convergence. Uh for years and + + + align:start position:0% +promise in convergence. Uh for years and +years and years, the telephone industry + + align:start position:0% +years and years, the telephone industry + + + align:start position:0% +years and years, the telephone industry +has been trying to branch out into + + align:start position:0% +has been trying to branch out into + + + align:start position:0% +has been trying to branch out into +interactive television. And there have + + align:start position:0% +interactive television. And there have + + + align:start position:0% +interactive television. And there have +been many trials going back 10 and 20 + + align:start position:0% +been many trials going back 10 and 20 + + + align:start position:0% +been many trials going back 10 and 20 +and 30 years, 40 years perhaps to + + align:start position:0% +and 30 years, 40 years perhaps to + + + align:start position:0% +and 30 years, 40 years perhaps to +develop two-way or interactive + + align:start position:0% +develop two-way or interactive + + + align:start position:0% +develop two-way or interactive +television. And they saw in the internet + + align:start position:0% +television. And they saw in the internet + + + align:start position:0% +television. And they saw in the internet +which is two-way and interactive a + + align:start position:0% +which is two-way and interactive a + + + align:start position:0% +which is two-way and interactive a +chance to finally get at the many um + + align:start position:0% +chance to finally get at the many um + + + align:start position:0% +chance to finally get at the many um +benefits that they saw to interactive + + align:start position:0% +benefits that they saw to interactive + + + align:start position:0% +benefits that they saw to interactive +television. So the television industry + + align:start position:0% +television. So the television industry + + + align:start position:0% +television. So the television industry +began approaching the internet and + + align:start position:0% +began approaching the internet and + + + align:start position:0% +began approaching the internet and +convergence and they got something quite + + align:start position:0% +convergence and they got something quite + + + align:start position:0% +convergence and they got something quite +different from what they were expecting. + + align:start position:0% +different from what they were expecting. + + + align:start position:0% +different from what they were expecting. +On the internet, the tradition is that + + align:start position:0% +On the internet, the tradition is that + + + align:start position:0% +On the internet, the tradition is that +content and carriage are separate. That + + align:start position:0% +content and carriage are separate. That + + + align:start position:0% +content and carriage are separate. That +is, there's the infrastructure of the + + align:start position:0% +is, there's the infrastructure of the + + + align:start position:0% +is, there's the infrastructure of the +network which is owned and operated and + + align:start position:0% +network which is owned and operated and + + + align:start position:0% +network which is owned and operated and +run by one group of people and then + + align:start position:0% +run by one group of people and then + + + align:start position:0% +run by one group of people and then +there's all this content which is + + align:start position:0% +there's all this content which is + + + align:start position:0% +there's all this content which is +carried on it and they're generally not + + align:start position:0% +carried on it and they're generally not + + + align:start position:0% +carried on it and they're generally not +owned by the same people. Well, in the + + align:start position:0% +owned by the same people. Well, in the + + + align:start position:0% +owned by the same people. Well, in the +television world, there's a great + + align:start position:0% +television world, there's a great + + + align:start position:0% +television world, there's a great +overlap between those who own the + + align:start position:0% +overlap between those who own the + + + align:start position:0% +overlap between those who own the +carriage and those who own the content. + + align:start position:0% +carriage and those who own the content. + + + align:start position:0% +carriage and those who own the content. +So, the business model of the television + + align:start position:0% +So, the business model of the television + + + align:start position:0% +So, the business model of the television +industry is different from the + + align:start position:0% +industry is different from the + + + align:start position:0% +industry is different from the +fundamental business model or evolving + + align:start position:0% +fundamental business model or evolving + + + align:start position:0% +fundamental business model or evolving +business models of the internet. So this + + align:start position:0% +business models of the internet. So this + + + align:start position:0% +business models of the internet. So this +was a problem and the television people + + align:start position:0% +was a problem and the television people + + + align:start position:0% +was a problem and the television people +were roundly criticized for linking + + align:start position:0% +were roundly criticized for linking + + + align:start position:0% +were roundly criticized for linking +content and carriage uh in their various + + align:start position:0% +content and carriage uh in their various + + + align:start position:0% +content and carriage uh in their various +schemes for deriving revenue from the + + align:start position:0% +schemes for deriving revenue from the + + + align:start position:0% +schemes for deriving revenue from the +internet. + + align:start position:0% +internet. + + + align:start position:0% +internet. +There was even worse development however + + align:start position:0% +There was even worse development however + + + align:start position:0% +There was even worse development however +for television people because television + + align:start position:0% +for television people because television + + + align:start position:0% +for television people because television +people uh for the most part are used to + + align:start position:0% +people uh for the most part are used to + + + align:start position:0% +people uh for the most part are used to +having five channels or 10 channels or + + align:start position:0% +having five channels or 10 channels or + + + align:start position:0% +having five channels or 10 channels or +20 channels. A restricted number of + + align:start position:0% +20 channels. A restricted number of + + + align:start position:0% +20 channels. A restricted number of +channels in which uh the attention of + + align:start position:0% +channels in which uh the attention of + + + align:start position:0% +channels in which uh the attention of +their viewers is uh channeled and so the + + align:start position:0% +their viewers is uh channeled and so the + + + align:start position:0% +their viewers is uh channeled and so the +competition among these channels is + + align:start position:0% +competition among these channels is + + + align:start position:0% +competition among these channels is +um um under their control pretty much. + + align:start position:0% +um um under their control pretty much. + + + align:start position:0% +um um under their control pretty much. +But on the internet there's not 10 + + align:start position:0% +But on the internet there's not 10 + + + align:start position:0% +But on the internet there's not 10 +channels or 100 channels or even 500 + + align:start position:0% +channels or 100 channels or even 500 + + + align:start position:0% +channels or 100 channels or even 500 +channels. On the internet there's a + + align:start position:0% +channels. On the internet there's a + + + align:start position:0% +channels. On the internet there's a +million channels that is every user of + + align:start position:0% +million channels that is every user of + + + align:start position:0% +million channels that is every user of +the internet can be a generator of + + align:start position:0% +the internet can be a generator of + + + align:start position:0% +the internet can be a generator of +content and the competition among u + + align:start position:0% +content and the competition among u + + + align:start position:0% +content and the competition among u +users of the internet that is providers + + align:start position:0% +users of the internet that is providers + + + align:start position:0% +users of the internet that is providers +of content in the internet the + + align:start position:0% +of content in the internet the + + + align:start position:0% +of content in the internet the +competition among them is much more + + align:start position:0% +competition among them is much more + + + align:start position:0% +competition among them is much more +fierce because the real scarce the real + + align:start position:0% +fierce because the real scarce the real + + + align:start position:0% +fierce because the real scarce the real +scarcity on the internet is not uh + + align:start position:0% +scarcity on the internet is not uh + + + align:start position:0% +scarcity on the internet is not uh +broadcast frequencies and it's not + + align:start position:0% +broadcast frequencies and it's not + + + align:start position:0% +broadcast frequencies and it's not +channels on the network it's the + + align:start position:0% +channels on the network it's the + + + align:start position:0% +channels on the network it's the +attention of readers and so the TV + + align:start position:0% +attention of readers and so the TV + + + align:start position:0% +attention of readers and so the TV +people confronted a business model that + + align:start position:0% +people confronted a business model that + + + align:start position:0% +people confronted a business model that +was alien to their experience but Still + + align:start position:0% +was alien to their experience but Still + + + align:start position:0% +was alien to their experience but Still +TV has been the convergence of the + + align:start position:0% +TV has been the convergence of the + + + align:start position:0% +TV has been the convergence of the +internet and television has been the + + align:start position:0% +internet and television has been the + + + align:start position:0% +internet and television has been the +most effective to date. Although when I + + align:start position:0% +most effective to date. Although when I + + + align:start position:0% +most effective to date. Although when I +say that you have to understand there + + align:start position:0% +say that you have to understand there + + + align:start position:0% +say that you have to understand there +are uh three kinds of television + + align:start position:0% +are uh three kinds of television + + + align:start position:0% +are uh three kinds of television +internet convergence of increasing + + align:start position:0% +internet convergence of increasing + + + align:start position:0% +internet convergence of increasing +importance. Uh the first kind of + + align:start position:0% +importance. Uh the first kind of + + + align:start position:0% +importance. Uh the first kind of +television internet convergence is the + + align:start position:0% +television internet convergence is the + + + align:start position:0% +television internet convergence is the +use of televisions as cheap computer + + align:start position:0% +use of televisions as cheap computer + + + align:start position:0% +use of televisions as cheap computer +monitors. And you saw this with such + + align:start position:0% +monitors. And you saw this with such + + + align:start position:0% +monitors. And you saw this with such +systems as you see this with such + + align:start position:0% +systems as you see this with such + + + align:start position:0% +systems as you see this with such +systems as web TV where really what + + align:start position:0% +systems as web TV where really what + + + align:start position:0% +systems as web TV where really what +you're doing is using the telephone + + align:start position:0% +you're doing is using the telephone + + + align:start position:0% +you're doing is using the telephone +network to connect to the internet but + + align:start position:0% +network to connect to the internet but + + + align:start position:0% +network to connect to the internet but +you're using your television as the + + align:start position:0% +you're using your television as the + + + align:start position:0% +you're using your television as the +monitor because televisions are + + align:start position:0% +monitor because televisions are + + + align:start position:0% +monitor because televisions are +generally cheaper than computer + + align:start position:0% +generally cheaper than computer + + + align:start position:0% +generally cheaper than computer +monitors. Uh this is really lowgrade + + align:start position:0% +monitors. Uh this is really lowgrade + + + align:start position:0% +monitors. Uh this is really lowgrade +convergence between television and the + + align:start position:0% +convergence between television and the + + + align:start position:0% +convergence between television and the +internet and it hardly + + align:start position:0% +internet and it hardly + + + align:start position:0% +internet and it hardly +counts. The second more uh vital + + align:start position:0% +counts. The second more uh vital + + + align:start position:0% +counts. The second more uh vital +convergence is the use of cable modems + + align:start position:0% +convergence is the use of cable modems + + + align:start position:0% +convergence is the use of cable modems +to carry the internet over the + + align:start position:0% +to carry the internet over the + + + align:start position:0% +to carry the internet over the +television network. And it turns out + + align:start position:0% +television network. And it turns out + + + align:start position:0% +television network. And it turns out +that cable modems have been the most + + align:start position:0% +that cable modems have been the most + + + align:start position:0% +that cable modems have been the most +effective the most uh widely deployed + + align:start position:0% +effective the most uh widely deployed + + + align:start position:0% +effective the most uh widely deployed +method of uh delivering internet + + align:start position:0% +method of uh delivering internet + + + align:start position:0% +method of uh delivering internet +services at higher speeds to consumers. + + align:start position:0% +services at higher speeds to consumers. + + + align:start position:0% +services at higher speeds to consumers. +But still cable modems is a is a weaker + + align:start position:0% +But still cable modems is a is a weaker + + + align:start position:0% +But still cable modems is a is a weaker +form of convergence between television + + align:start position:0% +form of convergence between television + + + align:start position:0% +form of convergence between television +and internet. The real convergence is + + align:start position:0% +and internet. The real convergence is + + + align:start position:0% +and internet. The real convergence is +when you can carry television over the + + align:start position:0% +when you can carry television over the + + + align:start position:0% +when you can carry television over the +internet which is I believe the intent + + align:start position:0% +internet which is I believe the intent + + + align:start position:0% +internet which is I believe the intent +of uh what you're watching now. This is + + align:start position:0% +of uh what you're watching now. This is + + + align:start position:0% +of uh what you're watching now. This is +supposed to be coming to you over the + + align:start position:0% +supposed to be coming to you over the + + + align:start position:0% +supposed to be coming to you over the +internet. So that's the convergence that + + align:start position:0% +internet. So that's the convergence that + + + align:start position:0% +internet. So that's the convergence that +I think we're after, the ability to + + align:start position:0% +I think we're after, the ability to + + + align:start position:0% +I think we're after, the ability to +carry uh video over the + + align:start position:0% +carry uh video over the + + + align:start position:0% +carry uh video over the +internet. Trouble is, the standard for + + align:start position:0% +internet. Trouble is, the standard for + + + align:start position:0% +internet. Trouble is, the standard for +carrying video over the internet is what + + align:start position:0% +carrying video over the internet is what + + + align:start position:0% +carrying video over the internet is what +I would call the jerky postage stamp. + + align:start position:0% +I would call the jerky postage stamp. + + + align:start position:0% +I would call the jerky postage stamp. +And you've all seen them when you try to + + align:start position:0% +And you've all seen them when you try to + + + align:start position:0% +And you've all seen them when you try to +watch video. Perhaps you're watching me + + align:start position:0% +watch video. Perhaps you're watching me + + + align:start position:0% +watch video. Perhaps you're watching me +now as a jerky postage stamp. A little + + align:start position:0% +now as a jerky postage stamp. A little + + + align:start position:0% +now as a jerky postage stamp. A little +tiny little square on your screen with + + align:start position:0% +tiny little square on your screen with + + + align:start position:0% +tiny little square on your screen with +me going like this. Of course, you can't + + align:start position:0% +me going like this. Of course, you can't + + + align:start position:0% +me going like this. Of course, you can't +tell that I'm doing this because I + + align:start position:0% +tell that I'm doing this because I + + + align:start position:0% +tell that I'm doing this because I +probably am already doing this in front + + align:start position:0% +probably am already doing this in front + + + align:start position:0% +probably am already doing this in front +of you right + + align:start position:0% +of you right + + + align:start position:0% +of you right +now. So, I'm I claim that convergence + + align:start position:0% +now. So, I'm I claim that convergence + + + align:start position:0% +now. So, I'm I claim that convergence +between television and the internet is + + align:start position:0% +between television and the internet is + + + align:start position:0% +between television and the internet is +the next big thing. But in saying so, u + + align:start position:0% +the next big thing. But in saying so, u + + + align:start position:0% +the next big thing. But in saying so, u +there's some serious uh work + + align:start position:0% + + + + align:start position:0% + +ahead. There's work ahead in the uh + + align:start position:0% +ahead. There's work ahead in the uh + + + align:start position:0% +ahead. There's work ahead in the uh +proliferation of the video internet. And + + align:start position:0% +proliferation of the video internet. And + + + align:start position:0% +proliferation of the video internet. And +among the work to be done is the + + align:start position:0% +among the work to be done is the + + + align:start position:0% +among the work to be done is the +deployment of what's called broadband to + + align:start position:0% +deployment of what's called broadband to + + + align:start position:0% +deployment of what's called broadband to +homes. Uh, as I mentioned earlier, most + + align:start position:0% +homes. Uh, as I mentioned earlier, most + + + align:start position:0% +homes. Uh, as I mentioned earlier, most +people access the internet through a + + align:start position:0% +people access the internet through a + + + align:start position:0% +people access the internet through a +dialup telephone modem at a pitiful 56 + + align:start position:0% +dialup telephone modem at a pitiful 56 + + + align:start position:0% +dialup telephone modem at a pitiful 56 +kilobits per second or less. But in + + align:start position:0% +kilobits per second or less. But in + + + align:start position:0% +kilobits per second or less. But in +order to put video in the internet, + + align:start position:0% +order to put video in the internet, + + + align:start position:0% +order to put video in the internet, +we're going to have to carry bits quite + + align:start position:0% +we're going to have to carry bits quite + + + align:start position:0% +we're going to have to carry bits quite +a bit faster than that. A funny problem + + align:start position:0% +a bit faster than that. A funny problem + + + align:start position:0% +a bit faster than that. A funny problem +has emerged. Uh, we have lots of + + align:start position:0% +has emerged. Uh, we have lots of + + + align:start position:0% +has emerged. Uh, we have lots of +bandwidth in the long haul on the + + align:start position:0% +bandwidth in the long haul on the + + + align:start position:0% +bandwidth in the long haul on the +internet thanks to uh amazing + + align:start position:0% +internet thanks to uh amazing + + + align:start position:0% +internet thanks to uh amazing +technologies like wave division + + align:start position:0% +technologies like wave division + + + align:start position:0% +technologies like wave division +multiplexing where we're carrying now + + align:start position:0% +multiplexing where we're carrying now + + + align:start position:0% +multiplexing where we're carrying now +approaching a terabit per second on a + + align:start position:0% +approaching a terabit per second on a + + + align:start position:0% +approaching a terabit per second on a +single fiber. We have plenty of + + align:start position:0% +single fiber. We have plenty of + + + align:start position:0% +single fiber. We have plenty of +bandwidth in the long distance and + + align:start position:0% +bandwidth in the long distance and + + + align:start position:0% +bandwidth in the long distance and +thanks to local area networks like my + + align:start position:0% +thanks to local area networks like my + + + align:start position:0% +thanks to local area networks like my +own baby Ethernet, we have plenty of + + align:start position:0% +own baby Ethernet, we have plenty of + + + align:start position:0% +own baby Ethernet, we have plenty of +bandwidth in the local area that is with + + align:start position:0% +bandwidth in the local area that is with + + + align:start position:0% +bandwidth in the local area that is with +inside of buildings. But there's a gap + + align:start position:0% +inside of buildings. But there's a gap + + + align:start position:0% +inside of buildings. But there's a gap +there's a gap between the LAN the local + + align:start position:0% +there's a gap between the LAN the local + + + align:start position:0% +there's a gap between the LAN the local +area network and the WAN the wide area + + align:start position:0% +area network and the WAN the wide area + + + align:start position:0% +area network and the WAN the wide area +network. And that's we'll call that + + align:start position:0% +network. And that's we'll call that + + + align:start position:0% +network. And that's we'll call that +access bandwidth getting from the LAN to + + align:start position:0% +access bandwidth getting from the LAN to + + + align:start position:0% +access bandwidth getting from the LAN to +the WAN. And there is a chasm currently + + align:start position:0% +the WAN. And there is a chasm currently + + + align:start position:0% +the WAN. And there is a chasm currently +bridged for most people by this + + align:start position:0% +bridged for most people by this + + + align:start position:0% +bridged for most people by this +low-speed dialup telephone modem. So + + align:start position:0% +low-speed dialup telephone modem. So + + + align:start position:0% +low-speed dialup telephone modem. So +part of the work is getting that chasm + + align:start position:0% +part of the work is getting that chasm + + + align:start position:0% +part of the work is getting that chasm +bridged and there's a variety of ways of + + align:start position:0% +bridged and there's a variety of ways of + + + align:start position:0% +bridged and there's a variety of ways of +doing it, some better than + + align:start position:0% +doing it, some better than + + + align:start position:0% +doing it, some better than +others. Most of the so-called broadband + + align:start position:0% +others. Most of the so-called broadband + + + align:start position:0% +others. Most of the so-called broadband +uh methods of access u most many of them + + align:start position:0% +uh methods of access u most many of them + + + align:start position:0% +uh methods of access u most many of them +are through an old-fashioned system + + align:start position:0% +are through an old-fashioned system + + + align:start position:0% +are through an old-fashioned system +called + + align:start position:0% +called + + + align:start position:0% +called +ISDN. And believe me, it would do you no + + align:start position:0% +ISDN. And believe me, it would do you no + + + align:start position:0% +ISDN. And believe me, it would do you no +good for me to explain what ISDN + + align:start position:0% +good for me to explain what ISDN + + + align:start position:0% +good for me to explain what ISDN +actually means. Suffice to say, it's a + + align:start position:0% +actually means. Suffice to say, it's a + + + align:start position:0% +actually means. Suffice to say, it's a +way of accessing going from the LAN to + + align:start position:0% +way of accessing going from the LAN to + + + align:start position:0% +way of accessing going from the LAN to +the WAN at up to about 128 kilobits per + + align:start position:0% +the WAN at up to about 128 kilobits per + + + align:start position:0% +the WAN at up to about 128 kilobits per +second, which isn't much faster than 56 + + align:start position:0% +second, which isn't much faster than 56 + + + align:start position:0% +second, which isn't much faster than 56 +kilobits per second. And it's a it's a + + align:start position:0% +kilobits per second. And it's a it's a + + + align:start position:0% +kilobits per second. And it's a it's a +sad comment in our time that most U + + align:start position:0% +sad comment in our time that most U + + + align:start position:0% +sad comment in our time that most U +market analysts include ISDN under the + + align:start position:0% +market analysts include ISDN under the + + + align:start position:0% +market analysts include ISDN under the +rubric broadband when really it's much + + align:start position:0% +rubric broadband when really it's much + + + align:start position:0% +rubric broadband when really it's much +too slow to be considered broadband. + + align:start position:0% +too slow to be considered broadband. + + + align:start position:0% +too slow to be considered broadband. +Uh the next uh method of bridging the + + align:start position:0% +Uh the next uh method of bridging the + + + align:start position:0% +Uh the next uh method of bridging the +bandwidth chasm here is DSL digital + + align:start position:0% +bandwidth chasm here is DSL digital + + + align:start position:0% +bandwidth chasm here is DSL digital +subscriber lines that is using the + + align:start position:0% +subscriber lines that is using the + + + align:start position:0% +subscriber lines that is using the +copper of uh that was installed for the + + align:start position:0% +copper of uh that was installed for the + + + align:start position:0% +copper of uh that was installed for the +telephone network to carry data at high + + align:start position:0% +telephone network to carry data at high + + + align:start position:0% +telephone network to carry data at high +speeds at uh 384 kilobits per second at + + align:start position:0% +speeds at uh 384 kilobits per second at + + + align:start position:0% +speeds at uh 384 kilobits per second at +1.5 megabits per second DSL and DSL is + + align:start position:0% +1.5 megabits per second DSL and DSL is + + + align:start position:0% +1.5 megabits per second DSL and DSL is +being deployed over now as we speak over + + align:start position:0% +being deployed over now as we speak over + + + align:start position:0% +being deployed over now as we speak over +the copper network uh by a variety of + + align:start position:0% +the copper network uh by a variety of + + + align:start position:0% +the copper network uh by a variety of +players including mostly the uh + + align:start position:0% +players including mostly the uh + + + align:start position:0% +players including mostly the uh +telephone uh copper + + align:start position:0% +telephone uh copper + + + align:start position:0% +telephone uh copper +monopolies. Another uh method of + + align:start position:0% +monopolies. Another uh method of + + + align:start position:0% +monopolies. Another uh method of +bridging the chasm is cable modems. As I + + align:start position:0% +bridging the chasm is cable modems. As I + + + align:start position:0% +bridging the chasm is cable modems. As I +mentioned earlier, the use of the cable + + align:start position:0% +mentioned earlier, the use of the cable + + + align:start position:0% +mentioned earlier, the use of the cable +television distribution network which + + align:start position:0% +television distribution network which + + + align:start position:0% +television distribution network which +reaches about 65 million homes in the + + align:start position:0% +reaches about 65 million homes in the + + + align:start position:0% +reaches about 65 million homes in the +United States out of 110 million. Uh and + + align:start position:0% +United States out of 110 million. Uh and + + + align:start position:0% +United States out of 110 million. Uh and +cable modems are the leading method of + + align:start position:0% +cable modems are the leading method of + + + align:start position:0% +cable modems are the leading method of +bridging uh the chasm of local area to + + align:start position:0% +bridging uh the chasm of local area to + + + align:start position:0% +bridging uh the chasm of local area to +wide area. And then there are some other + + align:start position:0% +wide area. And then there are some other + + + align:start position:0% +wide area. And then there are some other +technologies which we hope will come + + align:start position:0% +technologies which we hope will come + + + align:start position:0% +technologies which we hope will come +along to uh add to the alternatives and + + align:start position:0% +along to uh add to the alternatives and + + + align:start position:0% +along to uh add to the alternatives and +create more competition in solving that + + align:start position:0% +create more competition in solving that + + + align:start position:0% +create more competition in solving that +problem. Now in 2001 the cable modems + + align:start position:0% +problem. Now in 2001 the cable modems + + + align:start position:0% +problem. Now in 2001 the cable modems +are winning. That is there are more + + align:start position:0% +are winning. That is there are more + + + align:start position:0% +are winning. That is there are more +homes connected at higher speeds through + + align:start position:0% +homes connected at higher speeds through + + + align:start position:0% +homes connected at higher speeds through +cable modems and through digital + + align:start position:0% +cable modems and through digital + + + align:start position:0% +cable modems and through digital +subscriber lines than through DSL. And + + align:start position:0% +subscriber lines than through DSL. And + + + align:start position:0% +subscriber lines than through DSL. And +that can be explained very simply. The + + align:start position:0% +that can be explained very simply. The + + + align:start position:0% +that can be explained very simply. The +cable monopolies have weaker monopolies + + align:start position:0% +cable monopolies have weaker monopolies + + + align:start position:0% +cable monopolies have weaker monopolies +than the telephone monopolies. The + + align:start position:0% +than the telephone monopolies. The + + + align:start position:0% +than the telephone monopolies. The +telephone companies are huge and they + + align:start position:0% +telephone companies are huge and they + + + align:start position:0% +telephone companies are huge and they +have airtight monopolies on their + + align:start position:0% +have airtight monopolies on their + + + align:start position:0% +have airtight monopolies on their +geographies and so their motivation for + + align:start position:0% +geographies and so their motivation for + + + align:start position:0% +geographies and so their motivation for +installing digital subscriber lines is + + align:start position:0% +installing digital subscriber lines is + + + align:start position:0% +installing digital subscriber lines is +much lower. They have no one pressuring + + align:start position:0% +much lower. They have no one pressuring + + + align:start position:0% +much lower. They have no one pressuring +them to do very few people pressuring to + + align:start position:0% +them to do very few people pressuring to + + + align:start position:0% +them to do very few people pressuring to +do so. An industry did rise up in recent + + align:start position:0% +do so. An industry did rise up in recent + + + align:start position:0% +do so. An industry did rise up in recent +years uh to bring DSL to homes in large + + align:start position:0% +years uh to bring DSL to homes in large + + + align:start position:0% +years uh to bring DSL to homes in large +numbers in competition with the u + + align:start position:0% +numbers in competition with the u + + + align:start position:0% +numbers in competition with the u +entrenched uh incumbent local exchange + + align:start position:0% +entrenched uh incumbent local exchange + + + align:start position:0% +entrenched uh incumbent local exchange +carriers as they're called. But most of + + align:start position:0% +carriers as they're called. But most of + + + align:start position:0% +carriers as they're called. But most of +that competition uh has been throttled + + align:start position:0% +that competition uh has been throttled + + + align:start position:0% +that competition uh has been throttled +through the use of the monopoly power of + + align:start position:0% +through the use of the monopoly power of + + + align:start position:0% +through the use of the monopoly power of +the telephone companies. The u cable + + align:start position:0% +the telephone companies. The u cable + + + align:start position:0% +the telephone companies. The u cable +modems on the other hand are being + + align:start position:0% +modems on the other hand are being + + + align:start position:0% +modems on the other hand are being +proliferated by the uh cable companies + + align:start position:0% +proliferated by the uh cable companies + + + align:start position:0% +proliferated by the uh cable companies +which are themselves monopolies but + + align:start position:0% +which are themselves monopolies but + + + align:start position:0% +which are themselves monopolies but +they're much weaker monopolies. They + + align:start position:0% +they're much weaker monopolies. They + + + align:start position:0% +they're much weaker monopolies. They +they have much more competition uh from + + align:start position:0% +they have much more competition uh from + + + align:start position:0% +they have much more competition uh from +say satellite for example. uh and so + + align:start position:0% +say satellite for example. uh and so + + + align:start position:0% +say satellite for example. uh and so +they and plus they're more + + align:start position:0% +they and plus they're more + + + align:start position:0% +they and plus they're more +entrepreneurial and u energetic and + + align:start position:0% +entrepreneurial and u energetic and + + + align:start position:0% +entrepreneurial and u energetic and +they've been pr proliferating these + + align:start position:0% +they've been pr proliferating these + + + align:start position:0% +they've been pr proliferating these +cable modems and we should be rooting + + align:start position:0% +cable modems and we should be rooting + + + align:start position:0% +cable modems and we should be rooting +them on uh as the only uh way of uh + + align:start position:0% +them on uh as the only uh way of uh + + + align:start position:0% +them on uh as the only uh way of uh +stirring the telephone companies to + + align:start position:0% +stirring the telephone companies to + + + align:start position:0% +stirring the telephone companies to +movement. So we've had this recent bad + + align:start position:0% +movement. So we've had this recent bad + + + align:start position:0% +movement. So we've had this recent bad +news with the bursting of the dotcom + + align:start position:0% +news with the bursting of the dotcom + + + align:start position:0% +news with the bursting of the dotcom +bubble that is the telephone monopolies + + align:start position:0% +bubble that is the telephone monopolies + + + align:start position:0% +bubble that is the telephone monopolies +are more entrenched than ever uh in + + align:start position:0% +are more entrenched than ever uh in + + + align:start position:0% +are more entrenched than ever uh in +providing broadband and they will be + + align:start position:0% +providing broadband and they will be + + + align:start position:0% +providing broadband and they will be +slow to provide broadband but the + + align:start position:0% +slow to provide broadband but the + + + align:start position:0% +slow to provide broadband but the +broadband is being deployed and they are + + align:start position:0% +broadband is being deployed and they are + + + align:start position:0% +broadband is being deployed and they are +they will eventually get around to it + + align:start position:0% +they will eventually get around to it + + + align:start position:0% +they will eventually get around to it +and eventually and and uh broadband will + + align:start position:0% +and eventually and and uh broadband will + + + align:start position:0% +and eventually and and uh broadband will +begin to arrive in uh further and + + align:start position:0% +begin to arrive in uh further and + + + align:start position:0% +begin to arrive in uh further and +further and more and more places at + + align:start position:0% +further and more and more places at + + + align:start position:0% +further and more and more places at +faster and faster speeds and in that + + align:start position:0% +faster and faster speeds and in that + + + align:start position:0% +faster and faster speeds and in that +context we need to judge where to put + + align:start position:0% +context we need to judge where to put + + + align:start position:0% +context we need to judge where to put +video, what applications of video over + + align:start position:0% +video, what applications of video over + + + align:start position:0% +video, what applications of video over +what populations, over what businesses, + + align:start position:0% +what populations, over what businesses, + + + align:start position:0% +what populations, over what businesses, +small, large businesses, homes and so + + align:start position:0% +small, large businesses, homes and so + + + align:start position:0% +small, large businesses, homes and so +on. A very complicated strategy + + align:start position:0% +on. A very complicated strategy + + + align:start position:0% +on. A very complicated strategy +problem. So, one of the problems or + + align:start position:0% +problem. So, one of the problems or + + + align:start position:0% +problem. So, one of the problems or +another of the problems with the + + align:start position:0% +another of the problems with the + + + align:start position:0% +another of the problems with the +proliferation of internet video is the + + align:start position:0% +proliferation of internet video is the + + + align:start position:0% +proliferation of internet video is the +plumbing. And I'm a plumber, an internet + + align:start position:0% +plumbing. And I'm a plumber, an internet + + + align:start position:0% +plumbing. And I'm a plumber, an internet +plumber. So, let me talk a bit about the + + align:start position:0% +plumber. So, let me talk a bit about the + + + align:start position:0% +plumber. So, let me talk a bit about the +problems presented by the internet's + + align:start position:0% +problems presented by the internet's + + + align:start position:0% +problems presented by the internet's +plumbing. The uh term to describe the + + align:start position:0% +plumbing. The uh term to describe the + + + align:start position:0% +plumbing. The uh term to describe the +heart and soul of internet plumbing is + + align:start position:0% +heart and soul of internet plumbing is + + + align:start position:0% +heart and soul of internet plumbing is +TCPIP which is the name of the protocols + + align:start position:0% +TCPIP which is the name of the protocols + + + align:start position:0% +TCPIP which is the name of the protocols +that have been I guess they were + + align:start position:0% +that have been I guess they were + + + align:start position:0% +that have been I guess they were +installed in the internet in 1983. They + + align:start position:0% +installed in the internet in 1983. They + + + align:start position:0% +installed in the internet in 1983. They +were probably invented in + + align:start position:0% +were probably invented in + + + align:start position:0% +were probably invented in +1973. And these uh protocols um present + + align:start position:0% +1973. And these uh protocols um present + + + align:start position:0% +1973. And these uh protocols um present +problems for the carriage of video over + + align:start position:0% +problems for the carriage of video over + + + align:start position:0% +problems for the carriage of video over +the internet. When you try to in today's + + align:start position:0% +the internet. When you try to in today's + + + align:start position:0% +the internet. When you try to in today's +world when you try to carry video over + + align:start position:0% +world when you try to carry video over + + + align:start position:0% +world when you try to carry video over +the internet it's the uh plumbing is + + align:start position:0% +the internet it's the uh plumbing is + + + align:start position:0% +the internet it's the uh plumbing is +slow and it's lossy. that is information + + align:start position:0% +slow and it's lossy. that is information + + + align:start position:0% +slow and it's lossy. that is information +is lost and it's delayed jittery jittery + + align:start position:0% +is lost and it's delayed jittery jittery + + + align:start position:0% +is lost and it's delayed jittery jittery +and delayed when it gets there and these + + align:start position:0% +and delayed when it gets there and these + + + align:start position:0% +and delayed when it gets there and these +present problems for television. + + align:start position:0% +present problems for television. + + + align:start position:0% +present problems for television. +Television is much higher uses many more + + align:start position:0% +Television is much higher uses many more + + + align:start position:0% +Television is much higher uses many more +bits per second than telephone or the + + align:start position:0% +bits per second than telephone or the + + + align:start position:0% +bits per second than telephone or the +web. It relies on uh the data getting + + align:start position:0% +web. It relies on uh the data getting + + + align:start position:0% +web. It relies on uh the data getting +through reliably so that the whole + + align:start position:0% +through reliably so that the whole + + + align:start position:0% +through reliably so that the whole +picture gets painted not just little + + align:start position:0% +picture gets painted not just little + + + align:start position:0% +picture gets painted not just little +corners of the picture and it's uh real + + align:start position:0% +corners of the picture and it's uh real + + + align:start position:0% +corners of the picture and it's uh real +time you know I'm moving in real time + + align:start position:0% +time you know I'm moving in real time + + + align:start position:0% +time you know I'm moving in real time +and uh if the packets are delayed and I + + align:start position:0% +and uh if the packets are delayed and I + + + align:start position:0% +and uh if the packets are delayed and I +stop momentarily that's disruptive to um + + align:start position:0% +stop momentarily that's disruptive to um + + + align:start position:0% +stop momentarily that's disruptive to um +what you expect from video now there + + align:start position:0% +what you expect from video now there + + + align:start position:0% +what you expect from video now there +have been some efforts to solve the + + align:start position:0% +have been some efforts to solve the + + + align:start position:0% +have been some efforts to solve the +problems of the internet as a as + + align:start position:0% +problems of the internet as a as + + + align:start position:0% +problems of the internet as a as +plumbing for video and one of those is + + align:start position:0% +plumbing for video and one of those is + + + align:start position:0% +plumbing for video and one of those is +broadband deployment that I've just + + align:start position:0% +broadband deployment that I've just + + + align:start position:0% +broadband deployment that I've just +touched on that is increasing the speed + + align:start position:0% +touched on that is increasing the speed + + + align:start position:0% +touched on that is increasing the speed +of all the circuits so they can better + + align:start position:0% +of all the circuits so they can better + + + align:start position:0% +of all the circuits so they can better +carry video. But then there are protocol + + align:start position:0% +carry video. But then there are protocol + + + align:start position:0% +carry video. But then there are protocol +problems with the internet. The internet + + align:start position:0% +problems with the internet. The internet + + + align:start position:0% +problems with the internet. The internet +was never designed. It was designed in + + align:start position:0% +was never designed. It was designed in + + + align:start position:0% +was never designed. It was designed in +1973. I know I attended the meetings and + + align:start position:0% +1973. I know I attended the meetings and + + + align:start position:0% +1973. I know I attended the meetings and +it was no one was talking about video in + + align:start position:0% +it was no one was talking about video in + + + align:start position:0% +it was no one was talking about video in +1973 and not even in 1983 when it was + + align:start position:0% +1973 and not even in 1983 when it was + + + align:start position:0% +1973 and not even in 1983 when it was +finally deployed in the worldwide + + align:start position:0% +finally deployed in the worldwide + + + align:start position:0% +finally deployed in the worldwide +internet. But recently as we're trying + + align:start position:0% +internet. But recently as we're trying + + + align:start position:0% +internet. But recently as we're trying +to get video on the internet, there have + + align:start position:0% +to get video on the internet, there have + + + align:start position:0% +to get video on the internet, there have +been various proposals to fix TCPIP. + + align:start position:0% +been various proposals to fix TCPIP. + + + align:start position:0% +been various proposals to fix TCPIP. +Uh um one of those proposals is to + + align:start position:0% +Uh um one of those proposals is to + + + align:start position:0% +Uh um one of those proposals is to +replace TCP with various protocols. The + + align:start position:0% +replace TCP with various protocols. The + + + align:start position:0% +replace TCP with various protocols. The +one that comes to mind is RTP, the real + + align:start position:0% +one that comes to mind is RTP, the real + + + align:start position:0% +one that comes to mind is RTP, the real +time protocol to make up some of the + + align:start position:0% +time protocol to make up some of the + + + align:start position:0% +time protocol to make up some of the +deficiencies of + + align:start position:0% +deficiencies of + + + align:start position:0% +deficiencies of +TCP. Another solution has been the + + align:start position:0% +TCP. Another solution has been the + + + align:start position:0% +TCP. Another solution has been the +development of what's called MLS, multi- + + align:start position:0% +development of what's called MLS, multi- + + + align:start position:0% +development of what's called MLS, multi- +protocol labeling system. Actually, I'm + + align:start position:0% +protocol labeling system. Actually, I'm + + + align:start position:0% +protocol labeling system. Actually, I'm +not sure that's what it means, but + + align:start position:0% +not sure that's what it means, but + + + align:start position:0% +not sure that's what it means, but +that's a lower level fix of the plumbing + + align:start position:0% +that's a lower level fix of the plumbing + + + align:start position:0% +that's a lower level fix of the plumbing +whose purpose is to speed the packets + + align:start position:0% +whose purpose is to speed the packets + + + align:start position:0% +whose purpose is to speed the packets +through the network to reduce the losses + + align:start position:0% +through the network to reduce the losses + + + align:start position:0% +through the network to reduce the losses +uh that they encounter and to get them + + align:start position:0% +uh that they encounter and to get them + + + align:start position:0% +uh that they encounter and to get them +through in a shorter time and and with + + align:start position:0% +through in a shorter time and and with + + + align:start position:0% +through in a shorter time and and with +less uh jitter. While all this is going + + align:start position:0% +less uh jitter. While all this is going + + + align:start position:0% +less uh jitter. While all this is going +on, there have been great advances in + + align:start position:0% +on, there have been great advances in + + + align:start position:0% +on, there have been great advances in +the un the plumbing that underlies + + align:start position:0% +the un the plumbing that underlies + + + align:start position:0% +the un the plumbing that underlies +TCPIP. We've seen the development of + + align:start position:0% +TCPIP. We've seen the development of + + + align:start position:0% +TCPIP. We've seen the development of +wave division multiplexing which is the + + align:start position:0% +wave division multiplexing which is the + + + align:start position:0% +wave division multiplexing which is the +use of optical fibers to carry on + + align:start position:0% +use of optical fibers to carry on + + + align:start position:0% +use of optical fibers to carry on +different colors of light carrying very + + align:start position:0% +different colors of light carrying very + + + align:start position:0% +different colors of light carrying very +high-speed uh data. So you you might + + align:start position:0% +high-speed uh data. So you you might + + + align:start position:0% +high-speed uh data. So you you might +have an optical fiber with a thou a + + align:start position:0% +have an optical fiber with a thou a + + + align:start position:0% +have an optical fiber with a thou a +thousand different not quite we're not + + align:start position:0% +thousand different not quite we're not + + + align:start position:0% +thousand different not quite we're not +there yet but very shortly a thousand + + align:start position:0% +there yet but very shortly a thousand + + + align:start position:0% +there yet but very shortly a thousand +different colors of light each carrying + + align:start position:0% +different colors of light each carrying + + + align:start position:0% +different colors of light each carrying +10 or 20 or 30 or 40 gigabits per + + align:start position:0% +10 or 20 or 30 or 40 gigabits per + + + align:start position:0% +10 or 20 or 30 or 40 gigabits per +second. So we're talking about fibers + + align:start position:0% +second. So we're talking about fibers + + + align:start position:0% +second. So we're talking about fibers +carrying terabits per second and those + + align:start position:0% +carrying terabits per second and those + + + align:start position:0% +carrying terabits per second and those +speeds are very promising uh for + + align:start position:0% +speeds are very promising uh for + + + align:start position:0% +speeds are very promising uh for +carrying video. They for example are + + align:start position:0% +carrying video. They for example are + + + align:start position:0% +carrying video. They for example are +much larger than 1.5 gigabits per second + + align:start position:0% +much larger than 1.5 gigabits per second + + + align:start position:0% +much larger than 1.5 gigabits per second +which is how much how many bits come out + + align:start position:0% +which is how much how many bits come out + + + align:start position:0% +which is how much how many bits come out +of an HD TV highdefinition television + + align:start position:0% +of an HD TV highdefinition television + + + align:start position:0% +of an HD TV highdefinition television +camera. + + align:start position:0% +camera. + + + align:start position:0% +camera. +So underneath it all, underneath TCPIP + + align:start position:0% +So underneath it all, underneath TCPIP + + + align:start position:0% +So underneath it all, underneath TCPIP +is a development of this lambda + + align:start position:0% +is a development of this lambda + + + align:start position:0% +is a development of this lambda +switching network, the ability to carry + + align:start position:0% +switching network, the ability to carry + + + align:start position:0% +switching network, the ability to carry +lambdas, that is wavelengths of light + + align:start position:0% +lambdas, that is wavelengths of light + + + align:start position:0% +lambdas, that is wavelengths of light +over these fibers at very high speed uh + + align:start position:0% +over these fibers at very high speed uh + + + align:start position:0% +over these fibers at very high speed uh +and at very low cost. So, what's likely + + align:start position:0% +and at very low cost. So, what's likely + + + align:start position:0% +and at very low cost. So, what's likely +to happen, and I'm about to say + + align:start position:0% +to happen, and I'm about to say + + + align:start position:0% +to happen, and I'm about to say +something very controversial, what's + + align:start position:0% +something very controversial, what's + + + align:start position:0% +something very controversial, what's +about to happen is that the internet, + + align:start position:0% +about to happen is that the internet, + + + align:start position:0% +about to happen is that the internet, +which is trying to fix the TCP IP + + align:start position:0% +which is trying to fix the TCP IP + + + align:start position:0% +which is trying to fix the TCP IP +plumbing up here to better carry video, + + align:start position:0% +plumbing up here to better carry video, + + + align:start position:0% +plumbing up here to better carry video, +is going to be um overlaid or I guess + + align:start position:0% +is going to be um overlaid or I guess + + + align:start position:0% +is going to be um overlaid or I guess +the right word would be underlaid by a + + align:start position:0% +the right word would be underlaid by a + + + align:start position:0% +the right word would be underlaid by a +lambda switching network, which is not + + align:start position:0% +lambda switching network, which is not + + + align:start position:0% +lambda switching network, which is not +TCPIPbased, and that these two networks + + align:start position:0% +TCPIPbased, and that these two networks + + + align:start position:0% +TCPIPbased, and that these two networks +won't fight it out somehow, but they + + align:start position:0% +won't fight it out somehow, but they + + + align:start position:0% +won't fight it out somehow, but they +will be layered. Now, we see some of + + align:start position:0% +will be layered. Now, we see some of + + + align:start position:0% +will be layered. Now, we see some of +that even today. A I mean there there is + + align:start position:0% +that even today. A I mean there there is + + + align:start position:0% +that even today. A I mean there there is +precedent for this that is on the cable + + align:start position:0% +precedent for this that is on the cable + + + align:start position:0% +precedent for this that is on the cable +networks when you use cable modems the + + align:start position:0% +networks when you use cable modems the + + + align:start position:0% +networks when you use cable modems the +cable modems carry the TCP IP network on + + align:start position:0% +cable modems carry the TCP IP network on + + + align:start position:0% +cable modems carry the TCP IP network on +the same cable that uh television is + + align:start position:0% +the same cable that uh television is + + + align:start position:0% +the same cable that uh television is +carried that is there's already an + + align:start position:0% +carried that is there's already an + + + align:start position:0% +carried that is there's already an +overlay underlay structure in the cable + + align:start position:0% +overlay underlay structure in the cable + + + align:start position:0% +overlay underlay structure in the cable +television network I'm thinking that in + + align:start position:0% +television network I'm thinking that in + + + align:start position:0% +television network I'm thinking that in +order for us to get to widescale + + align:start position:0% +order for us to get to widescale + + + align:start position:0% +order for us to get to widescale +highdefinition video uh on the internet + + align:start position:0% +highdefinition video uh on the internet + + + align:start position:0% +highdefinition video uh on the internet +we're going to have to do a similar + + align:start position:0% +we're going to have to do a similar + + + align:start position:0% +we're going to have to do a similar +thing with the underlying lambda + + align:start position:0% +thing with the underlying lambda + + + align:start position:0% +thing with the underlying lambda +switching network and the overlying TCP + + align:start position:0% +switching network and the overlying TCP + + + align:start position:0% +switching network and the overlying TCP +IP internet + + align:start position:0% +IP internet + + + align:start position:0% +IP internet +network. On top of this plumbing, + + align:start position:0% +network. On top of this plumbing, + + + align:start position:0% +network. On top of this plumbing, +problematic plumbing for the video + + align:start position:0% +problematic plumbing for the video + + + align:start position:0% +problematic plumbing for the video +internet are what you might call the + + align:start position:0% +internet are what you might call the + + + align:start position:0% +internet are what you might call the +applications, video applications. And I + + align:start position:0% +applications, video applications. And I + + + align:start position:0% +applications, video applications. And I +talk about video as if I know what those + + align:start position:0% +talk about video as if I know what those + + + align:start position:0% +talk about video as if I know what those +applications are, but I don't and no one + + align:start position:0% +applications are, but I don't and no one + + + align:start position:0% +applications are, but I don't and no one +does. So, we're talking about various + + align:start position:0% +does. So, we're talking about various + + + align:start position:0% +does. So, we're talking about various +uses of the network that involve moving + + align:start position:0% +uses of the network that involve moving + + + align:start position:0% +uses of the network that involve moving +pictures and sound like you're watching + + align:start position:0% +pictures and sound like you're watching + + + align:start position:0% +pictures and sound like you're watching +now. And and the big question is I mean + + align:start position:0% +now. And and the big question is I mean + + + align:start position:0% +now. And and the big question is I mean +as this as the infrastructure is being + + align:start position:0% +as this as the infrastructure is being + + + align:start position:0% +as this as the infrastructure is being +deployed is what will these applications + + align:start position:0% +deployed is what will these applications + + + align:start position:0% +deployed is what will these applications +be what will drive deployment and how + + align:start position:0% +be what will drive deployment and how + + + align:start position:0% +be what will drive deployment and how +will this video be used uh for actual uh + + align:start position:0% +will this video be used uh for actual uh + + + align:start position:0% +will this video be used uh for actual uh +uh delivering valuable services. So + + align:start position:0% +uh delivering valuable services. So + + + align:start position:0% +uh delivering valuable services. So +there's a growing list of forms of video + + align:start position:0% +there's a growing list of forms of video + + + align:start position:0% +there's a growing list of forms of video +and the big question is will one of + + align:start position:0% +and the big question is will one of + + + align:start position:0% +and the big question is will one of +these forms or yet an undiscovered form + + align:start position:0% +these forms or yet an undiscovered form + + + align:start position:0% +these forms or yet an undiscovered form +of video rise up to be what we call in + + align:start position:0% +of video rise up to be what we call in + + + align:start position:0% +of video rise up to be what we call in +the computer industry as the killer app + + align:start position:0% +the computer industry as the killer app + + + align:start position:0% +the computer industry as the killer app +for the video + + align:start position:0% +for the video + + + align:start position:0% +for the video +internet. One long sought use of uh + + align:start position:0% +internet. One long sought use of uh + + + align:start position:0% +internet. One long sought use of uh +networks for video has is called video + + align:start position:0% +networks for video has is called video + + + align:start position:0% +networks for video has is called video +on demand. It used to be that you'd go + + align:start position:0% +on demand. It used to be that you'd go + + + align:start position:0% +on demand. It used to be that you'd go +to the movies to see a movie and then it + + align:start position:0% +to the movies to see a movie and then it + + + align:start position:0% +to the movies to see a movie and then it +got to be you'd walk down to the video + + align:start position:0% +got to be you'd walk down to the video + + + align:start position:0% +got to be you'd walk down to the video +rental store to get a video or you'd + + align:start position:0% +rental store to get a video or you'd + + + align:start position:0% +rental store to get a video or you'd +watch it on pay-per-view or cable + + align:start position:0% +watch it on pay-per-view or cable + + + align:start position:0% +watch it on pay-per-view or cable +television. There's some not some notion + + align:start position:0% +television. There's some not some notion + + + align:start position:0% +television. There's some not some notion +that people want to see video when they + + align:start position:0% +that people want to see video when they + + + align:start position:0% +that people want to see video when they +want to see it and they don't want to + + align:start position:0% +want to see it and they don't want to + + + align:start position:0% +want to see it and they don't want to +wait. Um, so being able to select a + + align:start position:0% +wait. Um, so being able to select a + + + align:start position:0% +wait. Um, so being able to select a +video and watch it right then when you + + align:start position:0% +video and watch it right then when you + + + align:start position:0% +video and watch it right then when you +want to watch it is called video on + + align:start position:0% +want to watch it is called video on + + + align:start position:0% +want to watch it is called video on +demand. So will we be using the internet + + align:start position:0% +demand. So will we be using the internet + + + align:start position:0% +demand. So will we be using the internet +for video on demand? Will that be the + + align:start position:0% +for video on demand? Will that be the + + + align:start position:0% +for video on demand? Will that be the +killer app? Will millions of people + + align:start position:0% +killer app? Will millions of people + + + align:start position:0% +killer app? Will millions of people +wanting to watch this video right when + + align:start position:0% +wanting to watch this video right when + + + align:start position:0% +wanting to watch this video right when +they want to watch it, will that that + + align:start position:0% +they want to watch it, will that that + + + align:start position:0% +they want to watch it, will that that +demand uh drive the proliferation of the + + align:start position:0% +demand uh drive the proliferation of the + + + align:start position:0% +demand uh drive the proliferation of the +video internet? Uh I don't know. In + + align:start position:0% +video internet? Uh I don't know. In + + + align:start position:0% +video internet? Uh I don't know. In +fact, I have a theory that it won't be. + + align:start position:0% +fact, I have a theory that it won't be. + + + align:start position:0% +fact, I have a theory that it won't be. +Another and let's call it an opposite + + align:start position:0% +Another and let's call it an opposite + + + align:start position:0% +Another and let's call it an opposite +kind of uh use of video would be video + + align:start position:0% +kind of uh use of video would be video + + + align:start position:0% +kind of uh use of video would be video +phone. For for decades, we have been + + align:start position:0% +phone. For for decades, we have been + + + align:start position:0% +phone. For for decades, we have been +trying to get to the video. Right now, + + align:start position:0% +trying to get to the video. Right now, + + + align:start position:0% +trying to get to the video. Right now, +telephone as you well know is just + + align:start position:0% +telephone as you well know is just + + + align:start position:0% +telephone as you well know is just +voice. And wouldn't it be nice to be + + align:start position:0% +voice. And wouldn't it be nice to be + + + align:start position:0% +voice. And wouldn't it be nice to be +able to see the person you're talking + + align:start position:0% +able to see the person you're talking + + + align:start position:0% +able to see the person you're talking +to? I think so. But video phone has been + + align:start position:0% +to? I think so. But video phone has been + + + align:start position:0% +to? I think so. But video phone has been +very hard to achieve. It's either been + + align:start position:0% +very hard to achieve. It's either been + + + align:start position:0% +very hard to achieve. It's either been +too expensive or too crummy or uh can we + + align:start position:0% +too expensive or too crummy or uh can we + + + align:start position:0% +too expensive or too crummy or uh can we +use the internet to finally introduce + + align:start position:0% +use the internet to finally introduce + + + align:start position:0% +use the internet to finally introduce +video phone? Now, this is different from + + align:start position:0% +video phone? Now, this is different from + + + align:start position:0% +video phone? Now, this is different from +video on demand. Video on demand has to + + align:start position:0% +video on demand. Video on demand has to + + + align:start position:0% +video on demand. Video on demand has to +do with the delivery of what they call + + align:start position:0% +do with the delivery of what they call + + + align:start position:0% +do with the delivery of what they call +content. Whereas the video phone is a + + align:start position:0% +content. Whereas the video phone is a + + + align:start position:0% +content. Whereas the video phone is a +deliverer of persontoperson + + align:start position:0% +deliverer of persontoperson + + + align:start position:0% +deliverer of persontoperson +communication. These are not nearly the + + align:start position:0% +communication. These are not nearly the + + + align:start position:0% +communication. These are not nearly the +same but they both involve video. Then + + align:start position:0% +same but they both involve video. Then + + + align:start position:0% +same but they both involve video. Then +there's video conferencing and there is + + align:start position:0% +there's video conferencing and there is + + + align:start position:0% +there's video conferencing and there is +a lot of video conferencing going on in + + align:start position:0% +a lot of video conferencing going on in + + + align:start position:0% +a lot of video conferencing going on in +the world. You know you go to a special + + align:start position:0% +the world. You know you go to a special + + + align:start position:0% +the world. You know you go to a special +room with a television and a camera and + + align:start position:0% +room with a television and a camera and + + + align:start position:0% +room with a television and a camera and +then groups of people can meet at great + + align:start position:0% +then groups of people can meet at great + + + align:start position:0% +then groups of people can meet at great +distances. Perhaps video conferencing + + align:start position:0% +distances. Perhaps video conferencing + + + align:start position:0% +distances. Perhaps video conferencing +moved over onto the video internet will + + align:start position:0% +moved over onto the video internet will + + + align:start position:0% +moved over onto the video internet will +be the killer app. And then there's + + align:start position:0% +be the killer app. And then there's + + + align:start position:0% +be the killer app. And then there's +email. Now email for 20 years and + + align:start position:0% +email. Now email for 20 years and + + + align:start position:0% +email. Now email for 20 years and +probably still is the killer app for the + + align:start position:0% +probably still is the killer app for the + + + align:start position:0% +probably still is the killer app for the +internet. What about video email? What + + align:start position:0% +internet. What about video email? What + + + align:start position:0% +internet. What about video email? What +about instead of typing in your me your + + align:start position:0% +about instead of typing in your me your + + + align:start position:0% +about instead of typing in your me your +short message, what if you just turned + + align:start position:0% +short message, what if you just turned + + + align:start position:0% +short message, what if you just turned +on the camera briefly to send a video uh + + align:start position:0% +on the camera briefly to send a video uh + + + align:start position:0% +on the camera briefly to send a video uh +email? So, that was a very short list + + align:start position:0% +email? So, that was a very short list + + + align:start position:0% +email? So, that was a very short list +and I think there will be many nuances + + align:start position:0% +and I think there will be many nuances + + + align:start position:0% +and I think there will be many nuances +of video and one of those or two of + + align:start position:0% +of video and one of those or two of + + + align:start position:0% +of video and one of those or two of +those will be the killer apps driving + + align:start position:0% +those will be the killer apps driving + + + align:start position:0% +those will be the killer apps driving +the proliferation of the video internet. + + align:start position:0% +the proliferation of the video internet. + + + align:start position:0% +the proliferation of the video internet. +I don't think we know uh what it is. + + align:start position:0% +I don't think we know uh what it is. + + + align:start position:0% +I don't think we know uh what it is. +Now, there are some people already + + align:start position:0% +Now, there are some people already + + + align:start position:0% +Now, there are some people already +starting businesses uh based on internet + + align:start position:0% +starting businesses uh based on internet + + + align:start position:0% +starting businesses uh based on internet +video. I'm on the board of one small + + align:start position:0% +video. I'm on the board of one small + + + align:start position:0% +video. I'm on the board of one small +company called Avastar and based on the + + align:start position:0% +company called Avastar and based on the + + + align:start position:0% +company called Avastar and based on the +state of the infrastructure today + + align:start position:0% +state of the infrastructure today + + + align:start position:0% +state of the infrastructure today +they're focused on delivering in essence + + align:start position:0% +they're focused on delivering in essence + + + align:start position:0% +they're focused on delivering in essence +video conferencing for companies + + align:start position:0% +video conferencing for companies + + + align:start position:0% +video conferencing for companies +enterprises of course they choose + + align:start position:0% +enterprises of course they choose + + + align:start position:0% +enterprises of course they choose +companies because homes don't have + + align:start position:0% +companies because homes don't have + + + align:start position:0% +companies because homes don't have +broadband sufficient to carry video + + align:start position:0% +broadband sufficient to carry video + + + align:start position:0% +broadband sufficient to carry video +whereas big companies do so there's + + align:start position:0% +whereas big companies do so there's + + + align:start position:0% +whereas big companies do so there's +infrastructure there uh Avastar has also + + align:start position:0% +infrastructure there uh Avastar has also + + + align:start position:0% +infrastructure there uh Avastar has also +decided that human beings have seen + + align:start position:0% +decided that human beings have seen + + + align:start position:0% +decided that human beings have seen +enough television that they won't really + + align:start position:0% +enough television that they won't really + + + align:start position:0% +enough television that they won't really +appreciate video until it's at least of + + align:start position:0% +appreciate video until it's at least of + + + align:start position:0% +appreciate video until it's at least of +television quality, not jerky postage + + align:start position:0% +television quality, not jerky postage + + + align:start position:0% +television quality, not jerky postage +stamps. So they their whole system is + + align:start position:0% +stamps. So they their whole system is + + + align:start position:0% +stamps. So they their whole system is +focused around + + align:start position:0% +focused around + + + align:start position:0% +focused around +delivering at least television quality + + align:start position:0% +delivering at least television quality + + + align:start position:0% +delivering at least television quality +if not high definition later uh uh + + align:start position:0% +if not high definition later uh uh + + + align:start position:0% +if not high definition later uh uh +television quality of a certain standard + + align:start position:0% +television quality of a certain standard + + + align:start position:0% +television quality of a certain standard +that is normal television and up not uh + + align:start position:0% +that is normal television and up not uh + + + align:start position:0% +that is normal television and up not uh +something down. But after that it + + align:start position:0% +something down. But after that it + + + align:start position:0% +something down. But after that it +becomes unclear as to what the uh the + + align:start position:0% +becomes unclear as to what the uh the + + + align:start position:0% +becomes unclear as to what the uh the +real applications are. As this little + + align:start position:0% +real applications are. As this little + + + align:start position:0% +real applications are. As this little +company introduces new features, they + + align:start position:0% +company introduces new features, they + + + align:start position:0% +company introduces new features, they +find that some features don't affect + + align:start position:0% +find that some features don't affect + + + align:start position:0% +find that some features don't affect +whether people use their network for + + align:start position:0% +whether people use their network for + + + align:start position:0% +whether people use their network for +desktoes video conferencing and other + + align:start position:0% +desktoes video conferencing and other + + + align:start position:0% +desktoes video conferencing and other +features have a dramatic effect on + + align:start position:0% +features have a dramatic effect on + + + align:start position:0% +features have a dramatic effect on +usage. Uh my my theory is that in in + + align:start position:0% +usage. Uh my my theory is that in in + + + align:start position:0% +usage. Uh my my theory is that in in +this case, this is a communication use + + align:start position:0% +this case, this is a communication use + + + align:start position:0% +this case, this is a communication use +of video. It's the and I've invented a + + align:start position:0% +of video. It's the and I've invented a + + + align:start position:0% +of video. It's the and I've invented a +word for this if you'll excuse me, the + + align:start position:0% +word for this if you'll excuse me, the + + + align:start position:0% +word for this if you'll excuse me, the +consummatability. When you make a video + + align:start position:0% +consummatability. When you make a video + + + align:start position:0% +consummatability. When you make a video +call, what is the probability that you + + align:start position:0% +call, what is the probability that you + + + align:start position:0% +call, what is the probability that you +get the job done? + + align:start position:0% +get the job done? + + + align:start position:0% +get the job done? +uh uh voicemail for example increases + + align:start position:0% +uh uh voicemail for example increases + + + align:start position:0% +uh uh voicemail for example increases +the consummatability of a telephone + + align:start position:0% +the consummatability of a telephone + + + align:start position:0% +the consummatability of a telephone +call. When you call someone it's not and + + align:start position:0% +call. When you call someone it's not and + + + align:start position:0% +call. When you call someone it's not and +you get no answer. You have not + + align:start position:0% +you get no answer. You have not + + + align:start position:0% +you get no answer. You have not +consummated your telephone call. But if + + align:start position:0% +consummated your telephone call. But if + + + align:start position:0% +consummated your telephone call. But if +you get an answering machine, well then + + align:start position:0% +you get an answering machine, well then + + + align:start position:0% +you get an answering machine, well then +you might be able to consummate the + + align:start position:0% +you might be able to consummate the + + + align:start position:0% +you might be able to consummate the +purpose of the call even if they're not + + align:start position:0% +purpose of the call even if they're not + + + align:start position:0% +purpose of the call even if they're not +there. Um I think what we're finding in + + align:start position:0% +there. Um I think what we're finding in + + + align:start position:0% +there. Um I think what we're finding in +the video world is that the + + align:start position:0% +the video world is that the + + + align:start position:0% +the video world is that the +consummatability of video calls is + + align:start position:0% +consummatability of video calls is + + + align:start position:0% +consummatability of video calls is +important. If you try to make a video + + align:start position:0% +important. If you try to make a video + + + align:start position:0% +important. If you try to make a video +call and the person's not there, if you + + align:start position:0% +call and the person's not there, if you + + + align:start position:0% +call and the person's not there, if you +have the opportunity to live a to leave + + align:start position:0% +have the opportunity to live a to leave + + + align:start position:0% +have the opportunity to live a to leave +a video mail instead, that increases the + + align:start position:0% +a video mail instead, that increases the + + + align:start position:0% +a video mail instead, that increases the +consummatability of the call and + + align:start position:0% +consummatability of the call and + + + align:start position:0% +consummatability of the call and +therefore its usage. + + align:start position:0% + + + + align:start position:0% + +So the picture I'd like to leave you + + align:start position:0% +So the picture I'd like to leave you + + + align:start position:0% +So the picture I'd like to leave you +with on the um emergence of the video + + align:start position:0% +with on the um emergence of the video + + + align:start position:0% +with on the um emergence of the video +internet is one of a 10 or 20 year + + align:start position:0% +internet is one of a 10 or 20 year + + + align:start position:0% +internet is one of a 10 or 20 year +process unfolding in a unpredictable + + align:start position:0% +process unfolding in a unpredictable + + + align:start position:0% +process unfolding in a unpredictable +ways with a lot of um experimentation + + align:start position:0% +ways with a lot of um experimentation + + + align:start position:0% +ways with a lot of um experimentation +and discovery going on uh in the + + align:start position:0% +and discovery going on uh in the + + + align:start position:0% +and discovery going on uh in the +meantime. And here are some of the + + align:start position:0% +meantime. And here are some of the + + + align:start position:0% +meantime. And here are some of the +phases that I anticipate will occur in + + align:start position:0% +phases that I anticipate will occur in + + + align:start position:0% +phases that I anticipate will occur in +this proliferation. + + align:start position:0% +this proliferation. + + + align:start position:0% +this proliferation. +uh often in the proliferation of a new + + align:start position:0% +uh often in the proliferation of a new + + + align:start position:0% +uh often in the proliferation of a new +technology or a new infrastructure + + align:start position:0% +technology or a new infrastructure + + + align:start position:0% +technology or a new infrastructure +there's an arbitrage factor that is the + + align:start position:0% +there's an arbitrage factor that is the + + + align:start position:0% +there's an arbitrage factor that is the +old way is expensive for artificial + + align:start position:0% +old way is expensive for artificial + + + align:start position:0% +old way is expensive for artificial +reasons for example regulation of the + + align:start position:0% +reasons for example regulation of the + + + align:start position:0% +reasons for example regulation of the +telephone network and the new technology + + align:start position:0% +telephone network and the new technology + + + align:start position:0% +telephone network and the new technology +arrives without the burden of that + + align:start position:0% +arrives without the burden of that + + + align:start position:0% +arrives without the burden of that +regulation and is able to just be + + align:start position:0% +regulation and is able to just be + + + align:start position:0% +regulation and is able to just be +cheaper better faster by version of + + align:start position:0% +cheaper better faster by version of + + + align:start position:0% +cheaper better faster by version of +arbitrage against the tariffs that are + + align:start position:0% +arbitrage against the tariffs that are + + + align:start position:0% +arbitrage against the tariffs that are +not really related to costs or + + align:start position:0% +not really related to costs or + + + align:start position:0% +not really related to costs or +underlying factors the arbitrage phase + + align:start position:0% +underlying factors the arbitrage phase + + + align:start position:0% +underlying factors the arbitrage phase +is frequently followed thereafter by + + align:start position:0% +is frequently followed thereafter by + + + align:start position:0% +is frequently followed thereafter by +actual cost savings that is the old way + + align:start position:0% +actual cost savings that is the old way + + + align:start position:0% +actual cost savings that is the old way +is more expensive than the new way + + align:start position:0% +is more expensive than the new way + + + align:start position:0% +is more expensive than the new way +intrinsically and so the new way begins + + align:start position:0% +intrinsically and so the new way begins + + + align:start position:0% +intrinsically and so the new way begins +to dominate. + + align:start position:0% +to dominate. + + + align:start position:0% +to dominate. +uh the new another phase often the third + + align:start position:0% +uh the new another phase often the third + + + align:start position:0% +uh the new another phase often the third +phase is where the the uh the new + + align:start position:0% +phase is where the the uh the new + + + align:start position:0% +phase is where the the uh the new +technology brings with it new + + align:start position:0% +technology brings with it new + + + align:start position:0% +technology brings with it new +applications that were previously not + + align:start position:0% +applications that were previously not + + + align:start position:0% +applications that were previously not +possible with the old technology and + + align:start position:0% +possible with the old technology and + + + align:start position:0% +possible with the old technology and +that's attractive to people to do + + align:start position:0% +that's attractive to people to do + + + align:start position:0% +that's attractive to people to do +entirely new things not to do the old + + align:start position:0% +entirely new things not to do the old + + + align:start position:0% +entirely new things not to do the old +things better cheaper faster but to do + + align:start position:0% +things better cheaper faster but to do + + + align:start position:0% +things better cheaper faster but to do +new things then after that you begin to + + align:start position:0% +new things then after that you begin to + + + align:start position:0% +new things then after that you begin to +see the convergence of the old and the + + align:start position:0% +see the convergence of the old and the + + + align:start position:0% +see the convergence of the old and the +new the integration of the old and the + + align:start position:0% +new the integration of the old and the + + + align:start position:0% +new the integration of the old and the +new so for example video pure video like + + align:start position:0% +new so for example video pure video like + + + align:start position:0% +new so for example video pure video like +you're watching now is probably not the + + align:start position:0% +you're watching now is probably not the + + + align:start position:0% +you're watching now is probably not the +right answer. Ultimately, it'll probably + + align:start position:0% +right answer. Ultimately, it'll probably + + + align:start position:0% +right answer. Ultimately, it'll probably +be the connection of video with + + align:start position:0% +be the connection of video with + + + align:start position:0% +be the connection of video with +PowerPoint, video with telephone, video + + align:start position:0% +PowerPoint, video with telephone, video + + + align:start position:0% +PowerPoint, video with telephone, video +with conferencing, that is an + + align:start position:0% +with conferencing, that is an + + + align:start position:0% +with conferencing, that is an +integration across applications that + + align:start position:0% +integration across applications that + + + align:start position:0% +integration across applications that +were previously uh separate. And then uh + + align:start position:0% +were previously uh separate. And then uh + + + align:start position:0% +were previously uh separate. And then uh +other factors which pace the + + align:start position:0% +other factors which pace the + + + align:start position:0% +other factors which pace the +proliferation of the infrastructure have + + align:start position:0% +proliferation of the infrastructure have + + + align:start position:0% +proliferation of the infrastructure have +to do with the making of standards. + + align:start position:0% +to do with the making of standards. + + + align:start position:0% +to do with the making of standards. +These technologies uh must be + + align:start position:0% +These technologies uh must be + + + align:start position:0% +These technologies uh must be +standardized over time. that is uh + + align:start position:0% +standardized over time. that is uh + + + align:start position:0% +standardized over time. that is uh +communication and content delivery + + align:start position:0% +communication and content delivery + + + align:start position:0% +communication and content delivery +infrastructures require standardization + + align:start position:0% +infrastructures require standardization + + + align:start position:0% +infrastructures require standardization +because they require vast investments in + + align:start position:0% +because they require vast investments in + + + align:start position:0% +because they require vast investments in +infrastructure and no one is willing to + + align:start position:0% +infrastructure and no one is willing to + + + align:start position:0% +infrastructure and no one is willing to +make infrastructural investments uh + + align:start position:0% +make infrastructural investments uh + + + align:start position:0% +make infrastructural investments uh +without standards. If they are willing + + align:start position:0% +without standards. If they are willing + + + align:start position:0% +without standards. If they are willing +they're unwise because when you invest a + + align:start position:0% +they're unwise because when you invest a + + + align:start position:0% +they're unwise because when you invest a +lot of money you want to be sure to have + + align:start position:0% +lot of money you want to be sure to have + + + align:start position:0% +lot of money you want to be sure to have +standards so that you have multiple + + align:start position:0% +standards so that you have multiple + + + align:start position:0% +standards so that you have multiple +suppliers that you can set against each + + align:start position:0% +suppliers that you can set against each + + + align:start position:0% +suppliers that you can set against each +other in a competitive environment. + + align:start position:0% +other in a competitive environment. + + + align:start position:0% +other in a competitive environment. +A question which arises in this + + align:start position:0% +A question which arises in this + + + align:start position:0% +A question which arises in this +unfolding is as I mentioned the which + + align:start position:0% +unfolding is as I mentioned the which + + + align:start position:0% +unfolding is as I mentioned the which +will be the killer apps and we have + + align:start position:0% +will be the killer apps and we have + + + align:start position:0% +will be the killer apps and we have +these broad categories that we've seen + + align:start position:0% +these broad categories that we've seen + + + align:start position:0% +these broad categories that we've seen +emerge on the prevideo internet we had + + align:start position:0% +emerge on the prevideo internet we had + + + align:start position:0% +emerge on the prevideo internet we had +the emergence as I mentioned of the + + align:start position:0% +the emergence as I mentioned of the + + + align:start position:0% +the emergence as I mentioned of the +publishing web web publishing where that + + align:start position:0% +publishing web web publishing where that + + + align:start position:0% +publishing web web publishing where that +was content delivery in a new way then + + align:start position:0% +was content delivery in a new way then + + + align:start position:0% +was content delivery in a new way then +we had uh uh communication and it's been + + align:start position:0% +we had uh uh communication and it's been + + + align:start position:0% +we had uh uh communication and it's been +in the history of the internet + + align:start position:0% +in the history of the internet + + + align:start position:0% +in the history of the internet +communication has been the more vital + + align:start position:0% +communication has been the more vital + + + align:start position:0% +communication has been the more vital +use rather than delivery of content In + + align:start position:0% +use rather than delivery of content In + + + align:start position:0% +use rather than delivery of content In +the early days of the internet, there + + align:start position:0% +the early days of the internet, there + + + align:start position:0% +the early days of the internet, there +was Compius and Prodigy that were + + align:start position:0% +was Compius and Prodigy that were + + + align:start position:0% +was Compius and Prodigy that were +contentoriented and along came America + + align:start position:0% +contentoriented and along came America + + + align:start position:0% +contentoriented and along came America +Online which was very + + align:start position:0% +Online which was very + + + align:start position:0% +Online which was very +communicationoriented and we know which + + align:start position:0% +communicationoriented and we know which + + + align:start position:0% +communicationoriented and we know which +ones uh one that is communication proved + + align:start position:0% +ones uh one that is communication proved + + + align:start position:0% +ones uh one that is communication proved +to be the more at least in the short + + align:start position:0% +to be the more at least in the short + + + align:start position:0% +to be the more at least in the short +term the more desirable um use the more + + align:start position:0% +term the more desirable um use the more + + + align:start position:0% +term the more desirable um use the more +driving use and then came commerce. So + + align:start position:0% +driving use and then came commerce. So + + + align:start position:0% +driving use and then came commerce. So +we had communication, content, + + align:start position:0% +we had communication, content, + + + align:start position:0% +we had communication, content, +communication and commerce and and we + + align:start position:0% +communication and commerce and and we + + + align:start position:0% +communication and commerce and and we +can wonder and guess whether that same + + align:start position:0% +can wonder and guess whether that same + + + align:start position:0% +can wonder and guess whether that same +evolution will uh recapitulate itself in + + align:start position:0% +evolution will uh recapitulate itself in + + + align:start position:0% +evolution will uh recapitulate itself in +the video internet. Now video has in the + + align:start position:0% +the video internet. Now video has in the + + + align:start position:0% +the video internet. Now video has in the +past been driven by entertainment. + + align:start position:0% +past been driven by entertainment. + + + align:start position:0% +past been driven by entertainment. +Television is mostly uh entertainment + + align:start position:0% +Television is mostly uh entertainment + + + align:start position:0% +Television is mostly uh entertainment +and it's an advertising business model + + align:start position:0% +and it's an advertising business model + + + align:start position:0% +and it's an advertising business model +for the most part although increasingly + + align:start position:0% +for the most part although increasingly + + + align:start position:0% +for the most part although increasingly +there are subscriptions but there it's I + + align:start position:0% +there are subscriptions but there it's I + + + align:start position:0% +there are subscriptions but there it's I +think it's best to think of it as an + + align:start position:0% +think it's best to think of it as an + + + align:start position:0% +think it's best to think of it as an +advertising entertainmentdriven medium. + + align:start position:0% +advertising entertainmentdriven medium. + + + align:start position:0% +advertising entertainmentdriven medium. +How will that be affected by integration + + align:start position:0% +How will that be affected by integration + + + align:start position:0% +How will that be affected by integration +with the internet? Uh I think internet + + align:start position:0% +with the internet? Uh I think internet + + + align:start position:0% +with the internet? Uh I think internet +will uh entertainment will drive uh + + align:start position:0% +will uh entertainment will drive uh + + + align:start position:0% +will uh entertainment will drive uh +adoptance of the adoption of the video + + align:start position:0% +adoptance of the adoption of the video + + + align:start position:0% +adoptance of the adoption of the video +internet. Uh and that has some good uh + + align:start position:0% +internet. Uh and that has some good uh + + + align:start position:0% +internet. Uh and that has some good uh +will have some good uh implications for + + align:start position:0% +will have some good uh implications for + + + align:start position:0% +will have some good uh implications for +education. We we talk about education on + + align:start position:0% +education. We we talk about education on + + + align:start position:0% +education. We we talk about education on +the internet and the use of the internet + + align:start position:0% +the internet and the use of the internet + + + align:start position:0% +the internet and the use of the internet +in education. And I think as video and + + align:start position:0% +in education. And I think as video and + + + align:start position:0% +in education. And I think as video and +entertainment get into the internet, + + align:start position:0% +entertainment get into the internet, + + + align:start position:0% +entertainment get into the internet, +this bodess well for education because + + align:start position:0% +this bodess well for education because + + + align:start position:0% +this bodess well for education because +right now education competes with + + align:start position:0% +right now education competes with + + + align:start position:0% +right now education competes with +entertainment on an uneven footing. The + + align:start position:0% +entertainment on an uneven footing. The + + + align:start position:0% +entertainment on an uneven footing. The +uh entertainment model allows for high + + align:start position:0% +uh entertainment model allows for high + + + align:start position:0% +uh entertainment model allows for high +production values which are attractive + + align:start position:0% +production values which are attractive + + + align:start position:0% +production values which are attractive +to the uh uh to kids whereas the + + align:start position:0% +to the uh uh to kids whereas the + + + align:start position:0% +to the uh uh to kids whereas the +entertainment the education business + + align:start position:0% +entertainment the education business + + + align:start position:0% +entertainment the education business +does not have the same access to + + align:start position:0% +does not have the same access to + + + align:start position:0% +does not have the same access to +production values. So there's kind of a + + align:start position:0% +production values. So there's kind of a + + + align:start position:0% +production values. So there's kind of a +uh I mean thank goodness for the + + align:start position:0% +uh I mean thank goodness for the + + + align:start position:0% +uh I mean thank goodness for the +discovery channel which does have high + + align:start position:0% +discovery channel which does have high + + + align:start position:0% +discovery channel which does have high +production values. So there you see an + + align:start position:0% +production values. So there you see an + + + align:start position:0% +production values. So there you see an +example where if you raise the + + align:start position:0% +example where if you raise the + + + align:start position:0% +example where if you raise the +production values of education it can + + align:start position:0% +production values of education it can + + + align:start position:0% +production values of education it can +then compete on an even footing with uh + + align:start position:0% +then compete on an even footing with uh + + + align:start position:0% +then compete on an even footing with uh +entertainment. So as we get video on the + + align:start position:0% +entertainment. So as we get video on the + + + align:start position:0% +entertainment. So as we get video on the +internet and the general facilities for + + align:start position:0% +internet and the general facilities for + + + align:start position:0% +internet and the general facilities for +increasing production values on the + + align:start position:0% +increasing production values on the + + + align:start position:0% +increasing production values on the +internet and as the infrastructure + + align:start position:0% +internet and as the infrastructure + + + align:start position:0% +internet and as the infrastructure +improves for delivering those production + + align:start position:0% +improves for delivering those production + + + align:start position:0% +improves for delivering those production +values, I think this will have a related + + align:start position:0% +values, I think this will have a related + + + align:start position:0% +values, I think this will have a related +benefit to the use of the internet uh + + align:start position:0% +benefit to the use of the internet uh + + + align:start position:0% +benefit to the use of the internet uh +for education. It's getting to the point + + align:start position:0% +for education. It's getting to the point + + + align:start position:0% +for education. It's getting to the point +now where we can begin to think uh not + + align:start position:0% +now where we can begin to think uh not + + + align:start position:0% +now where we can begin to think uh not +so much of putting the internet in + + align:start position:0% +so much of putting the internet in + + + align:start position:0% +so much of putting the internet in +schools but instead using the internet + + align:start position:0% +schools but instead using the internet + + + align:start position:0% +schools but instead using the internet +instead of schools. That is if as we + + align:start position:0% +instead of schools. That is if as we + + + align:start position:0% +instead of schools. That is if as we +begin to have a very high bandwidth and + + align:start position:0% +begin to have a very high bandwidth and + + + align:start position:0% +begin to have a very high bandwidth and +ubiquitous internet with uh video more + + align:start position:0% +ubiquitous internet with uh video more + + + align:start position:0% +ubiquitous internet with uh video more +and more it can be used for education uh + + align:start position:0% +and more it can be used for education uh + + + align:start position:0% +and more it can be used for education uh +from the home instead of uh busing + + align:start position:0% +from the home instead of uh busing + + + align:start position:0% +from the home instead of uh busing +people off to remote places to be taught + + align:start position:0% +people off to remote places to be taught + + + align:start position:0% +people off to remote places to be taught +with uh chalk on + + align:start position:0% +with uh chalk on + + + align:start position:0% +with uh chalk on +slate. I'd like to close with a short + + align:start position:0% +slate. I'd like to close with a short + + + align:start position:0% +slate. I'd like to close with a short +story of a recent interaction that I had + + align:start position:0% +story of a recent interaction that I had + + + align:start position:0% +story of a recent interaction that I had +with video over the internet. Uh only + + align:start position:0% +with video over the internet. Uh only + + + align:start position:0% +with video over the internet. Uh only +this wasn't just normal video. This was + + align:start position:0% +this wasn't just normal video. This was + + + align:start position:0% +this wasn't just normal video. This was +highdefin television, a coming thing in + + align:start position:0% +highdefin television, a coming thing in + + + align:start position:0% +highdefin television, a coming thing in +video. And this wasn't just the + + align:start position:0% +video. And this wasn't just the + + + align:start position:0% +video. And this wasn't just the +internet. This was internet 2, the new + + align:start position:0% +internet. This was internet 2, the new + + + align:start position:0% +internet. This was internet 2, the new +version of the internet, much higher + + align:start position:0% +version of the internet, much higher + + + align:start position:0% +version of the internet, much higher +speed version of the internet that + + align:start position:0% +speed version of the internet that + + + align:start position:0% +speed version of the internet that +people are working on. And I was asked + + align:start position:0% +people are working on. And I was asked + + + align:start position:0% +people are working on. And I was asked +to do a short video presentation, not + + align:start position:0% +to do a short video presentation, not + + + align:start position:0% +to do a short video presentation, not +unlike this one uh from here at from MIT + + align:start position:0% +unlike this one uh from here at from MIT + + + align:start position:0% +unlike this one uh from here at from MIT +uh to be delivered on a huge screen at a + + align:start position:0% +uh to be delivered on a huge screen at a + + + align:start position:0% +uh to be delivered on a huge screen at a +conference center in uh Las Vegas. Uh in + + align:start position:0% +conference center in uh Las Vegas. Uh in + + + align:start position:0% +conference center in uh Las Vegas. Uh in +fact, it was part of the keynote address + + align:start position:0% +fact, it was part of the keynote address + + + align:start position:0% +fact, it was part of the keynote address +of uh Craig Barrett from Intel. So I + + align:start position:0% +of uh Craig Barrett from Intel. So I + + + align:start position:0% +of uh Craig Barrett from Intel. So I +arrived at this room over here at MIT + + align:start position:0% +arrived at this room over here at MIT + + + align:start position:0% +arrived at this room over here at MIT +across campus where there was a + + align:start position:0% +across campus where there was a + + + align:start position:0% +across campus where there was a +highdefinition camera and out of that + + align:start position:0% +highdefinition camera and out of that + + + align:start position:0% +highdefinition camera and out of that +camera came 1.5 gigabits billion bits + + align:start position:0% +camera came 1.5 gigabits billion bits + + + align:start position:0% +camera came 1.5 gigabits billion bits +per second of video of a much higher + + align:start position:0% +per second of video of a much higher + + + align:start position:0% +per second of video of a much higher +quality version of me that went into + + align:start position:0% +quality version of me that went into + + + align:start position:0% +quality version of me that went into +these boxes. And there were people + + align:start position:0% +these boxes. And there were people + + + align:start position:0% +these boxes. And there were people +sitting around by the boxes running + + align:start position:0% +sitting around by the boxes running + + + align:start position:0% +sitting around by the boxes running +them. And those boxes would take this + + align:start position:0% +them. And those boxes would take this + + + align:start position:0% +them. And those boxes would take this +1.5 Gbits per second and crunch it down, + + align:start position:0% +1.5 Gbits per second and crunch it down, + + + align:start position:0% +1.5 Gbits per second and crunch it down, +compress it down to 20 megabits per + + align:start position:0% +compress it down to 20 megabits per + + + align:start position:0% +compress it down to 20 megabits per +second that was then carried over an e + + align:start position:0% +second that was then carried over an e + + + align:start position:0% +second that was then carried over an e +100 megabit per second Ethernet cable + + align:start position:0% +100 megabit per second Ethernet cable + + + align:start position:0% +100 megabit per second Ethernet cable +into internet 2 there in Cambridge here + + align:start position:0% +into internet 2 there in Cambridge here + + + align:start position:0% +into internet 2 there in Cambridge here +in Cambridge. And then it went several + + align:start position:0% +in Cambridge. And then it went several + + + align:start position:0% +in Cambridge. And then it went several +hops through the southern United States + + align:start position:0% +hops through the southern United States + + + align:start position:0% +hops through the southern United States +uh to arrive in uh Las Vegas at 2.4 + + align:start position:0% +uh to arrive in uh Las Vegas at 2.4 + + + align:start position:0% +uh to arrive in uh Las Vegas at 2.4 +gigabits per second. That is the speed + + align:start position:0% +gigabits per second. That is the speed + + + align:start position:0% +gigabits per second. That is the speed +of the circuits being used. + + align:start position:0% +of the circuits being used. + + + align:start position:0% +of the circuits being used. +Uh so I showed up to uh give this + + align:start position:0% +Uh so I showed up to uh give this + + + align:start position:0% +Uh so I showed up to uh give this +presentation and it was very exciting + + align:start position:0% +presentation and it was very exciting + + + align:start position:0% +presentation and it was very exciting +because this was the latest technology, + + align:start position:0% +because this was the latest technology, + + + align:start position:0% +because this was the latest technology, +the best of video and the best of the + + align:start position:0% +the best of video and the best of the + + + align:start position:0% +the best of video and the best of the +internet assembled uh for this short + + align:start position:0% +internet assembled uh for this short + + + align:start position:0% +internet assembled uh for this short +video presentation. Uh and I delivered + + align:start position:0% +video presentation. Uh and I delivered + + + align:start position:0% +video presentation. Uh and I delivered +the presentation and listened to what + + align:start position:0% +the presentation and listened to what + + + align:start position:0% +the presentation and listened to what +was going on around me. Now, + + align:start position:0% +was going on around me. Now, + + + align:start position:0% +was going on around me. Now, +unfortunately, my presentation fell at a + + align:start position:0% +unfortunately, my presentation fell at a + + + align:start position:0% +unfortunately, my presentation fell at a +time of day when the traffic on internet + + align:start position:0% +time of day when the traffic on internet + + + align:start position:0% +time of day when the traffic on internet +2 was a bit higher than usual. And so, + + align:start position:0% +2 was a bit higher than usual. And so, + + + align:start position:0% +2 was a bit higher than usual. And so, +the um the uh broadcast wasn't getting + + align:start position:0% +the um the uh broadcast wasn't getting + + + align:start position:0% +the um the uh broadcast wasn't getting +through reliably to Las Vegas, there was + + align:start position:0% +through reliably to Las Vegas, there was + + + align:start position:0% +through reliably to Las Vegas, there was +a bit of breaking up as of course in the + + align:start position:0% +a bit of breaking up as of course in the + + + align:start position:0% +a bit of breaking up as of course in the +internet, the way the internet works + + align:start position:0% +internet, the way the internet works + + + align:start position:0% +internet, the way the internet works +using TCP IP. When packets accidentally + + align:start position:0% +using TCP IP. When packets accidentally + + + align:start position:0% +using TCP IP. When packets accidentally +arrive in large numbers at a single + + align:start position:0% +arrive in large numbers at a single + + + align:start position:0% +arrive in large numbers at a single +place, some of them get lost. They're + + align:start position:0% +place, some of them get lost. They're + + + align:start position:0% +place, some of them get lost. They're +thrown away. Uh and this led to breakups + + align:start position:0% +thrown away. Uh and this led to breakups + + + align:start position:0% +thrown away. Uh and this led to breakups +in the video. Uh, fortunately, the video + + align:start position:0% +in the video. Uh, fortunately, the video + + + align:start position:0% +in the video. Uh, fortunately, the video +had been um recorded uh in Las Vegas + + align:start position:0% +had been um recorded uh in Las Vegas + + + align:start position:0% +had been um recorded uh in Las Vegas +just in case the internet didn't work + + align:start position:0% +just in case the internet didn't work + + + align:start position:0% +just in case the internet didn't work +during this particularly busy time of + + align:start position:0% +during this particularly busy time of + + + align:start position:0% +during this particularly busy time of +day. So, I'm thinking, uh-oh, is this + + align:start position:0% +day. So, I'm thinking, uh-oh, is this + + + align:start position:0% +day. So, I'm thinking, uh-oh, is this +good plumbing for the video internet? + + align:start position:0% +good plumbing for the video internet? + + + align:start position:0% +good plumbing for the video internet? +That didn't seem to be good plumbing. + + align:start position:0% +That didn't seem to be good plumbing. + + + align:start position:0% +That didn't seem to be good plumbing. +But there was a worse problem that even + + align:start position:0% +But there was a worse problem that even + + + align:start position:0% +But there was a worse problem that even +when the internet wasn't crowded and + + align:start position:0% +when the internet wasn't crowded and + + + align:start position:0% +when the internet wasn't crowded and +therefore failing to reliably deliver + + align:start position:0% +therefore failing to reliably deliver + + + align:start position:0% +therefore failing to reliably deliver +this video stream, there was another + + align:start position:0% +this video stream, there was another + + + align:start position:0% +this video stream, there was another +problem is that it took time to compress + + align:start position:0% +problem is that it took time to compress + + + align:start position:0% +problem is that it took time to compress +this video from the 1.5 gigs down to the + + align:start position:0% +this video from the 1.5 gigs down to the + + + align:start position:0% +this video from the 1.5 gigs down to the +20 megs. And it took time for it to wind + + align:start position:0% +20 megs. And it took time for it to wind + + + align:start position:0% +20 megs. And it took time for it to wind +its way through the internet routers uh + + align:start position:0% +its way through the internet routers uh + + + align:start position:0% +its way through the internet routers uh +that we've known so well over the last + + align:start position:0% +that we've known so well over the last + + + align:start position:0% +that we've known so well over the last +uh 30 years to get all the way to Las + + align:start position:0% +uh 30 years to get all the way to Las + + + align:start position:0% +uh 30 years to get all the way to Las +Vegas. So that in the end it took 4 + + align:start position:0% +Vegas. So that in the end it took 4 + + + align:start position:0% +Vegas. So that in the end it took 4 +seconds for my picture to to leave + + align:start position:0% +seconds for my picture to to leave + + + align:start position:0% +seconds for my picture to to leave +Cambridge and arrive in Las Vegas. Now + + align:start position:0% +Cambridge and arrive in Las Vegas. Now + + + align:start position:0% +Cambridge and arrive in Las Vegas. Now +it was a pretty picture to be sure, but + + align:start position:0% +it was a pretty picture to be sure, but + + + align:start position:0% +it was a pretty picture to be sure, but +it was not an interactive picture. Craig + + align:start position:0% +it was not an interactive picture. Craig + + + align:start position:0% +it was not an interactive picture. Craig +Barrett in Las Vegas and I could not + + align:start position:0% +Barrett in Las Vegas and I could not + + + align:start position:0% +Barrett in Las Vegas and I could not +really have much of a conversation + + align:start position:0% +really have much of a conversation + + + align:start position:0% +really have much of a conversation +because uh there's a 4se secondond + + align:start position:0% +because uh there's a 4se secondond + + + align:start position:0% +because uh there's a 4se secondond +delay. That would be 4 seconds this way + + align:start position:0% +delay. That would be 4 seconds this way + + + align:start position:0% +delay. That would be 4 seconds this way +and then 4 seconds back. That would be + + align:start position:0% +and then 4 seconds back. That would be + + + align:start position:0% +and then 4 seconds back. That would be +an 8-second roundtrip delay. + + align:start position:0% +an 8-second roundtrip delay. + + + align:start position:0% +an 8-second roundtrip delay. +uh it is generally believed that in + + align:start position:0% +uh it is generally believed that in + + + align:start position:0% +uh it is generally believed that in +order for that to work you need uh + + align:start position:0% +order for that to work you need uh + + + align:start position:0% +order for that to work you need uh +roundtrip delays in the milliseconds in + + align:start position:0% +roundtrip delays in the milliseconds in + + + align:start position:0% +roundtrip delays in the milliseconds in +a 100 milliseconds or 200 milliseconds + + align:start position:0% +a 100 milliseconds or 200 milliseconds + + + align:start position:0% +a 100 milliseconds or 200 milliseconds +not 8 seconds. So I took this little um + + align:start position:0% +not 8 seconds. So I took this little um + + + align:start position:0% +not 8 seconds. So I took this little um +interaction as sort of a progress + + align:start position:0% +interaction as sort of a progress + + + align:start position:0% +interaction as sort of a progress +milestone in the proliferation of + + align:start position:0% +milestone in the proliferation of + + + align:start position:0% +milestone in the proliferation of +internet video and my conclusion which + + align:start position:0% +internet video and my conclusion which + + + align:start position:0% +internet video and my conclusion which +you've you've already heard a bit of is + + align:start position:0% +you've you've already heard a bit of is + + + align:start position:0% +you've you've already heard a bit of is +that the internet is not the right + + align:start position:0% +that the internet is not the right + + + align:start position:0% +that the internet is not the right +plumbing for the video internet. We will + + align:start position:0% +plumbing for the video internet. We will + + + align:start position:0% +plumbing for the video internet. We will +call it the video internet. We will call + + align:start position:0% +call it the video internet. We will call + + + align:start position:0% +call it the video internet. We will call +it the internet but it's not going to be + + align:start position:0% +it the internet but it's not going to be + + + align:start position:0% +it the internet but it's not going to be +the internet we know and love today. I + + align:start position:0% +the internet we know and love today. I + + + align:start position:0% +the internet we know and love today. I +suspect that is the the time-tested TCP + + align:start position:0% +suspect that is the the time-tested TCP + + + align:start position:0% +suspect that is the the time-tested TCP +IP structure of the internet will have + + align:start position:0% +IP structure of the internet will have + + + align:start position:0% +IP structure of the internet will have +to be changed and as I mentioned earlier + + align:start position:0% +to be changed and as I mentioned earlier + + + align:start position:0% +to be changed and as I mentioned earlier +perhaps in this overlay fashion and + + align:start position:0% +perhaps in this overlay fashion and + + + align:start position:0% +perhaps in this overlay fashion and +underlying + + align:start position:0% +underlying + + + align:start position:0% +underlying +um dense wave division optical switch + + align:start position:0% +um dense wave division optical switch + + + align:start position:0% +um dense wave division optical switch +network underlying the TCP IP packet + + align:start position:0% +network underlying the TCP IP packet + + + align:start position:0% +network underlying the TCP IP packet +switch network in order to deliver + + align:start position:0% +switch network in order to deliver + + + align:start position:0% +switch network in order to deliver +highdefinition + + align:start position:0% +highdefinition + + + align:start position:0% +highdefinition +video and I also saw that this uh + + align:start position:0% +video and I also saw that this uh + + + align:start position:0% +video and I also saw that this uh +one-way application was not nearly as it + + align:start position:0% +one-way application was not nearly as it + + + align:start position:0% +one-way application was not nearly as it +would have been much more interesting I + + align:start position:0% +would have been much more interesting I + + + align:start position:0% +would have been much more interesting I +think to the audience uh if Craig + + align:start position:0% +think to the audience uh if Craig + + + align:start position:0% +think to the audience uh if Craig +Barrett and I were to argue about + + align:start position:0% +Barrett and I were to argue about + + + align:start position:0% +Barrett and I were to argue about +something, but we couldn't argue about + + align:start position:0% +something, but we couldn't argue about + + + align:start position:0% +something, but we couldn't argue about +something. Instead, the audience had to + + align:start position:0% +something. Instead, the audience had to + + + align:start position:0% +something. Instead, the audience had to +suffer a steady one-way stream of uh my + + align:start position:0% +suffer a steady one-way stream of uh my + + + align:start position:0% +suffer a steady one-way stream of uh my +words instead of interaction between + + align:start position:0% +words instead of interaction between + + + align:start position:0% +words instead of interaction between +Craig and I. So that the applications + + align:start position:0% +Craig and I. So that the applications + + + align:start position:0% +Craig and I. So that the applications +for video uh as I've mentioned there'll + + align:start position:0% +for video uh as I've mentioned there'll + + + align:start position:0% +for video uh as I've mentioned there'll +be considerable exper exciting + + align:start position:0% +be considerable exper exciting + + + align:start position:0% +be considerable exper exciting +experimentation ahead as to what kind of + + align:start position:0% +experimentation ahead as to what kind of + + + align:start position:0% +experimentation ahead as to what kind of +videobased applications or better yet + + align:start position:0% +videobased applications or better yet + + + align:start position:0% +videobased applications or better yet +where to put video in other applications + + align:start position:0% +where to put video in other applications + + + align:start position:0% +where to put video in other applications +to make them interesting and to compel + + align:start position:0% +to make them interesting and to compel + + + align:start position:0% +to make them interesting and to compel +the the deployment of video + + align:start position:0% +the the deployment of video + + + align:start position:0% +the the deployment of video +infrastructure. So in closing, it's + + align:start position:0% +infrastructure. So in closing, it's + + + align:start position:0% +infrastructure. So in closing, it's +going to take time. That little + + align:start position:0% +going to take time. That little + + + align:start position:0% +going to take time. That little +experiment in between Cambridge and Las + + align:start position:0% +experiment in between Cambridge and Las + + + align:start position:0% +experiment in between Cambridge and Las +Vegas indicated that video the video + + align:start position:0% +Vegas indicated that video the video + + + align:start position:0% +Vegas indicated that video the video +internet is not it may be the next big + + align:start position:0% +internet is not it may be the next big + + + align:start position:0% +internet is not it may be the next big +thing, but it's not going to come + + align:start position:0% +thing, but it's not going to come + + + align:start position:0% +thing, but it's not going to come +tomorrow. It's going to take as I + + align:start position:0% +tomorrow. It's going to take as I + + + align:start position:0% +tomorrow. It's going to take as I +mentioned earlier probably 10 to 20 + + align:start position:0% +mentioned earlier probably 10 to 20 + + + align:start position:0% +mentioned earlier probably 10 to 20 +years and these uh these years will be + + align:start position:0% +years and these uh these years will be + + + align:start position:0% +years and these uh these years will be +very interesting and I I look forward to + + align:start position:0% +very interesting and I I look forward to + + + align:start position:0% +very interesting and I I look forward to +them. Thank you. \ No newline at end of file diff --git a/qY5Rr-PTMMc.txt b/qY5Rr-PTMMc.txt new file mode 100644 index 0000000000000000000000000000000000000000..67adb57787c69e14109b6b99beda9fe8dc23da90 --- /dev/null +++ b/qY5Rr-PTMMc.txt @@ -0,0 +1,68 @@ +Let's look at a concrete example. + +This graph shows the voltage transfer characteristic +for a particular device and we're wondering + +if we can use this device as a combinational +inverter. + +In other words, can we pick values for the +voltage thresholds V_OL, V_IL, V_IH and V_OH + +so that the shown VTC meets the constraints +imposed on a combinational device? + +An inverter outputs a digital 1 when its input +is a digital 0 and vice versa. + +In fact this device does produce a high output +voltage when its input voltage is low, so + +there's a chance that this will work out. + +The lowest output voltage produced by the +device is 0.5V, so if the device is to produce + +a legal digital output of 0, we have to choose +V_OL to be at least 0.5V. + +We want the inverter to produce a valid digital +0 whenever its input is valid digital 1. + +Looking at the VTC, we see that if the input +is higher than 3V, the output will be less + +than or equal to V_OL, so let's set V_IH to +3V. + +We could set it to a higher value than 3V, +but we'll make it as low as possible to leave + +room for a generous high noise margin. + +That takes care of two of the four signal +thresholds, V_OL and V_IH. + +The other two thresholds are related to these +two by the noise margin N as shown by these + +two equations. + +Can we find a value for N such that V_OUT +>= V_OH when V_IN <= V_IL? + +If we chose N = 0.5V, then the formulas tell +us that V_IL = 1V and V_OH = 3.5V. + +Plotting these thresholds on the graph and +adding the forbidden regions, we see that + +happily the VTC is, in fact, legal! + +So we can use this device as a combinational +inverter if we use the signaling specification + +with V_OL = 0.5V, V_IL = 1V, V_IH = 3V and +V_OH = 3.5V. + +We're good to go! \ No newline at end of file diff --git a/qgA-JxgtjZg.txt b/qgA-JxgtjZg.txt new file mode 100644 index 0000000000000000000000000000000000000000..4869891a3bb9471d2b6869851e48ceee5f31045a --- /dev/null +++ b/qgA-JxgtjZg.txt @@ -0,0 +1,2906 @@ +The following content is +provided under a Creative + +Commons license. + +Your support will help MIT +OpenCourseWare continue to + +offer high quality educational +resources for free. + +To make a donation or view +additional materials from + +hundreds of MIT courses, visit +MIT OpenCourseWare at + +ocw.mit.edu. + +ESTHER DUFLO: So actually +a lot of themes are + +criss-crossing in this +documentary. + +It's pretty well done for +managing to bring many of + +those teams up. + +So before we sort of I summarize +them, I'd like to + +have your impression of what are +the themes that seem to be + +important in like how the +students get educated, the + +government's decisions, the +parent's decision, et cetera? + +Yeah, Ben? + +AUDIENCE: Cultural +preservation. + +I forget the other one. + +It was the Kurds, and who's-- + +ESTHER DUFLO: Just the rest of +Turkey, mainstream Turkey. + +AUDIENCE: --mainstream Turkey +and how they're willing to + +preserve their culture, and how +that spill-over effects + +[INAUDIBLE] how they operate +[INAUDIBLE]. + +ESTHER DUFLO: Right, so one +issue that is kind of there is + +whether the whole education is a +way to mainstream the Kurds, + +which they are suspicious +about. + +That's a good point. + +AUDIENCE: Yeah, I was going +to say infrastructure, so + +actually physically getting the +schools becomes a problem. + +The guy mentioned like when it +snows, it becomes hard for the + +children to get to school, +so they fall behind. + +And they have the desire to +become a boarding school, like + +religious schools actually +in their village. + +But because they don't have +that, it becomes difficult. + +ESTHER DUFLO: Right. + +So there is a supply +constraint. + +There are no schools in the +villages and getting to them-- + +they go by bus, but even that +is difficult, because + +infrastructure is difficult. + +AUDIENCE: It can also to be hard +to find justification for + +this education, because although +some people argue + +that there is still value to it, +even if girls or boys who + +get educated just come back to +the village and live with + +their family, but a +lot of people say, + +well, what is the point? + +ESTHER DUFLO: So there +is a question of + +the benefits of education. + +Yaprak's parents, what do they +think the benefit of education + +is for her? + +What do they expect from +the education? + +AUDIENCE: For her to come back +and contribute to the family. + +ESTHER DUFLO: Is it what they +say, or is it someone + +else who says that? + +What do the parents say, +the mom, and then + +Yaprak say it also. + +AUDIENCE: Her mom said +that she wanted + +her to become a doctor. + +ESTHER DUFLO: Her mom says she +wants her to become a doctor. + +She also wants to +become a doctor. + +And in fact there is this +debate where people are + +saying, well, what's the point +of education if we don't have + +a job that will take into +account this education? + +And there's this other guy who +says, well, even if she + +doesn't become a doctor, there +are these other things. + +But it seems to have +a little bit of a + +minority view in this. + +You don't see any anyone asking +her the question, but + +she answers, saying, +yeah, yeah, there + +would be some value. + +But there's somewhat +of a debate there. + +AUDIENCE: When you're talking +about supply, there's a lack + +of supply of teachers +over there. + +So in particular regions, like +the eastern region for + +example, teachers have +to go out into those + +cultural sort of things. + +They're coming from +different regions + +where culture's different. + +And then at the same +time, they may not + +particularly be there. + +They're passing through. + +You mentioned that do we go to +train or to get experience in + +this way and them move on. + +So there's not sustainability. + +When you think about teaching, +it's important that teachers + +build relationships +with students and + +really pour into them. + +But when they're in this like +transit sort of mindset, it + +becomes a little hard +to do that. + +ESTHER DUFLO: Right, so that's +another supply issue from the + +supply side is whether there +are enough teachers. + +And then that kind of interacts +like it was a + +cultural issue. + +Who were the teachers? + +I think you're making +two points + +that are both important. + +One is the point that the +teachers who are coming to + +them may not be as motivated. + +They might not be accountable +to the community. + +They might be difficult +to discipline. + +They might not care. + +In addition, they might be the +ones who are trying to teach + +in Turk and not and not in +Kurd, and all of that. + +So that brings the cultural +dimension. + +Yup? + +AUDIENCE: Another thing I didn't +realize whether or not + +they mentioned in that movie. + +But there's a problem if all +these girls are actually + +living in those boarding schools +for most of the week. + +And they're just going +back for the weekend. + +You know, they don't have that +sort of family [INAUDIBLE] + +that's going to actually +give them more balance. + +So even though they'll be +getting an education, there's + +a huge drawback for the fact +that they don't have their + +parents right there and +telling them what + +they have to do. + +And nobody really knows +what that could + +cause in the long run. + +ESTHER DUFLO: Like you guys, +far from your families-- + +yeah, I think this sort of +comes a little bit in + +[INAUDIBLE] + +when they have this debate about +I think they would like + +to have the schools +in their villages. + +That don't like to send the +kids to boarding school. + +I think one issue is are the +kids mature enough to manage + +in boarding school? + +And the other which +is in [INAUDIBLE] + +of that, are they going +to become different? + +Are they going to absolve these +values that these guys + +are not necessarily +looking for? + +There might also be a slight +conflict underlying this, + +where actually from the point +of view of the Turkish + +government, who is trying +to make the Kurds + +into regular Turks. + +It's actually a good +thing to get them + +away from the families. + +But from the point of the view +of the Kurd, that's kind of a + +way of following +the exhibition. + +So that's one thing that goes +with education, which you find + +in a lot of places. + +For example, there was a big +education drive in Indonesia + +that I'm going to talk +in a bit, which had + +exactly the same idea. + +Education is about +imparting skills. + +It's also about imparting +a world view. + +And therefore that creates +conflict between the different + +people who have different +ideas about what these + +worldviews should be. + +AUDIENCE: Maybe also that those +parents talked about the + +lack of [INAUDIBLE] + +practical things maybe teach +about agriculture [INAUDIBLE]? + +ESTHER DUFLO: Yes, so that goes +back to what is the value + +of education? + +What's the benefit +of education? + +So it comes back to well, fine, +if she graduates and + +becomes a doctor, +that's great. + +But if not, what has +education brought? + +Maybe nothing. + +People might not necessarily see +the value of the education + +that's imparted as being that +great, unless you can make it + +to being a doctor, which would +be great, but is a + +bit more of a leap. + +AUDIENCE: I just have +a question. + +So I figured how many children +were in the household. + +My understanding is that they +only send one to school, like + +the impact that has on the +children who aren't in school. + +I know the mom at least said +that she wasn't happy as she + +would like to be [INAUDIBLE] +education [INAUDIBLE]. + +But is that mindset perpetuated +because you have a + +child who's going to school kind +of puts you in further + +[INAUDIBLE] your current +circumstances, which could + +pose another problem. + +ESTHER DUFLO: That's an +interesting question. + +For example, the sister +of this girl, Yaprak. + +what's her name? + +Was [? Meemet. ?] + +She wasn't in school, because +she was too old to benefit + +from the compulsory education. + +So on the one hand, she gets +some indirect benefits, + +[INAUDIBLE] + +benefits from the fact that +Yaprak is educated. + +On the other hand, she also +gets like these education + +envy, and feels that, oh, it +would have been great if I + +could have been educated +myself. + +So that's an interesting +point. + +AUDIENCE: We kind of spoke about +this before, but just + +the idea of the value of +education and what are the + +returns to it? + +So when you're most poor, you're +just kind of raising + +everything higher. + +When you think about education, +the returns are + +going to be much farther off. + +This was sort of mentioned, but +you get to a certain point + +and you need some education, +then after a while, it's kind + +of like, well, you'll probably +be more valuable if you just + +stayed home and helped +out around the house. + +There's a dichotomy, I guess, +between the social pressure + +for education and the +home pressure to + +help your family out. + +We need to eat tomorrow, +so this is a + +little bit more important. + +You'll be able to go to school +when you feel like it, or when + +you get a little bit older. + +Or maybe you won't need to go +to school because we need a + +survivor now. + +ESTHER DUFLO: Right, so there's +another cost of that + +in the cost of getting yourself +to school, and that + +now the government is paying for +the bus, and is paying for + +the school, et cetera. + +But there is another cost, which +is in economic jargon we + +call the opportunity cost, +which is while you're in + +school, you're not helping +out on the house. + +And that is something that is +mentioned in the movie at some + +point, where they're saying, +well, that's kind of one + +reason why people are not +complying to the objectives. + +People are feeling that they +are getting on their house. + +And you said it exactly right. + +There is a trade off. + +Even if you don't bear the +direct cost of schooling like + +is the case here, there is +a trade off between the + +opportunity cost, when you're +losing the value of the child + +work now, and the benefits +that are far out in the + +future, potentially very far out +in the future if you think + +that it's worth getting an +education, only if you can + +become a doctor. + +AUDIENCE: I was going to say, if +the child goes back to the + +village, then they just wasted +their time, essentially, if + +they weren't helping out. + +ESTHER DUFLO: So that is the +debate that they have at some + +point, which is at least some +people feel that if you go + +back to the village, you +just wasted your time. + +So the only value is +to being a doctor. + +And at the same time they +realize that it's not super + +likely that it happens. + +And then in general, if someone +says that it's easier + +for men than for women to get +jobs outside the village, + +there might be the other point +I made earlier, that they + +might not want the girls +to really leave to + +be outside the village. + +They might accept for them to +leave to be a doctor, but they + +might be less likely to let them +leave to man a register + +in a supermarket, which maybe is +a job you could get with a + +good education without +continuing. + +And so if you're not going to +leave the village to take that + +job, and they feel that there +is no value in between, then + +you would have no reason to +pay the opportunity cost. + +So that's where kind of this +debate or tension comes up. + +Is any of it valuable? + +Or is it only valuable if I +achieve a sufficient amount to + +really get like the lottery +ticket of having a chance to + +become a doctor. + +So what does this bring, this +idea that the benefits of + +education may or may not be +obtained from the first years + +of education? + +We might be able to obtain +them only if + +we get enough education. + +What does that remind you +of that we have seen? + +It's that idea of the S shape. + +So the question, and here, +again, at this level, as usual + +it's a question. + +Is there S shape in education? + +So are the first few years of +education valuable, because + +you learn how to socialize. + +That's what they said +in the movie. + +You learn how to socialize. + +You learn family planning. + +You learn maybe to read the +instruction in the packet of + +fertilizer for when you +come back to the farm. + +So there might be reason to +think that even the first + +years of educations +would be valuable. + +Or is it the case that the first +year of education are + +not really valuable, that the +only thing that's worth it is + +a college education. + +And the first year of education, +all that gives you + +is the option value of going to +high school and college if + +you want to. + +The latter case is a case where +there is an S shape. + +So unless you get enough +education, it's not worth it. + +At the former case is a case +where there is no S shape. + +And so one empirical question is +whether it's actually an S + +shape or it's actually +not an S shape. + +Another empirical question, +of course, is the value of + +education, whatever the +shape the overall + +level of the benefits. + +And the third question is what +people are thinking? + +Because even if it's in fact +linear, if people think that + +it's actually S shape, +then it's going to + +influence their behavior. + +And it's going to influence +the choice + +that they are making. + +So for example here, they have +all these discussions about is + +it even worth it to send the +kids to school or not. + +And they never question the fact +that it would be great if + +she could become a doctor. + +But they might question the +fact that there might be a + +value of anything below +being a doctor. + +Is there anything else that +comes out of this? + +Yeah? + +AUDIENCE: I think Ben +might have talked. + +I heard him say something +about cultural-- + +but just the idea of the head +scarves, the preventing of the + +girls from going to school, +and then the idea of Kurds + +being assimilated as opposed to +being integrated in a way + +that helps them maintain +their culture. + +Again, that's something +that would deter me + +from going to school. + +ESTHER DUFLO: Right, so that's +kind of the convex combination + +of the two points, Ben's point +and the point about once you + +send them to boarding school, +they're not under your thumb. + +You can't check what they are +doing anymore, which is + +reinforcing in Turkey that's +it's not allowed to wear a + +head scarf in school. + +So from the beginning, there +is a conflict there. + +Is school aware of +indoctrinating the kids away + +from what you would like, under +the guise of providing + +them with valuable skills +in the labor market? + +And there is certainly some +amount of that, to be honest, + +that's actually said by them. + +The only thing we missed +from the movie-- + +well, we might have missed a bit +more-- but the only piece + +we missed that I remember and +is worth pointing out is the + +woman with the hair like that +who speaks with this very posh + +English accent, the columnist +from The Economist. + +She has the last word. + +And she mentions one thing that +might be worth pointing + +out, which is this is compulsory +education. + +This drive to compulsory +education was very much of a + +top down intervention, was done +without any consultation, + +or anybody, which is done. + +And the way the schools are run +is run in this completely + +centralized way, with a +centralized curriculum, with + +the teachers appointed from the +center, the kids driven to + +boarding school, et cetera. + +And she says that that's not +going to work, that people are + +not going to accept or not going +to really be in the mood + +or thought to be really groovy +about the whole education + +thing, unless they're +given some autonomy + +in running the schools. + +So that's an important point, +because that's the point that + +many people make, that any +effort at top down education + +will meet some resistance +from the people. + +They might still go because +they have to go, but the + +parents won't be very engaged. + +The children won't +be very engaged. + +The teachers might not +be very engaged. + +And nothing will happen. + +So we keep that in mind. + +I'm channeling her, because I +want to keep that in mind as + +we have the discussion. + +Because this tension between +education, board-funded top + +down, and education, emerging +from the bottom up, is one of + +the central debates +in education. + +So I think you guys said a +lot of the things that I + +wanted to touch on. + +Let me kind of make sure that +we have everything together. + +So the stories of a Kurdish +girl who goes to boarding + +school after education was made + +compulsory until grade eight. + +So many important themes +appear in the movie. + +I think we mentioned them. + +One are all the questions about +the supply of education, + +so that seems to have been a +constraint before this big + +education push from the Turkish +government and still + +is a constraint. + +There is no schools in +the remote villages. + +The roads are bad. + +Transportation is difficult. + +There is a shortage of +well-trained teachers. + +Therefore there is a large class +size, and the teachers + +are moving, what you were saying +about the teachers + +coming from far away not being +necessarily the best teacher, + +most motivated teacher. + +For part of the international +community, these types of + +constraint are the only thing +you have to worry about. + +I think you guys have all seen +a picture of a little African + +girl in a village saying, that +if only she had a school, she + +would study until she would +become a doctor. + +So there is a whole branch of +the international community, + +governments, et cetera, for whom +the only problems with + +education are supply problems, +and if only we could get rid + +of the supply problem and make +sure there are enough + +well-trained teachers, then the +kids would go to school. + +They would learn something +in school. + +And they would all +be very educated. + +So the problem is a problem of +fixing the supply constraint. + +But what we see in the movie is +that these are not the only + +constraints. + +So the reason why it's relevant +is that a lot of the + +international community, a lot +of the policy was in aid. + +And the policies implemented +by the government have that + +flavor in mind, which is let's +fix the supply problem. + +So for example, a lot of African +countries have gotten + +rid of school fees completely to +make sure school was free. + +You go to a country like Kenya, +and there is a school + +every 25 meters, because every +community who wants a school + +can gets one. + +So there is plenty of schools. + +In some sense, one could say too +many schools in that the + +class size is actually quite +small at the top. + +And in India, it's +the same thing. + +India is debating a right to +education, where if you don't + +have a school right near your +village, you can get one. + +But what we see in the movie +is that it's not the supply + +constraint, not having a school +near you, et cetera, is + +not the new problem. + +In fact, Turkey is not only +building schools, and building + +these boarding schools, and +having kids travel in + +minibuses to go to the school, +they also made education + +compulsory. + +And if the only problem was +supply, then making education + +compulsory would not +be necessary. + +You would put the schools there +and people would be + +delighted to go. + +And you wouldn't need +any compulsion. + +In fact, Turkey decided that the +only way that they could + +get a fast increasing education +was to make + +education compulsory. + +So implicitly, there is the +argument that, well, maybe + +people would not want to +go to all the schools. + +So there must be a demand +constraint as well. + +There must be a lower demand +for education. + +So what constrained them? + +We mentioned that. + +One is no economic resources. + +So they don't have money. + +So this in principle, the direct +cost of education can + +be compensated by making +education free by paying for + +books, by paying for +transportation. + +But there is also the need +for child labor. + +It was mentioned in the movie. + +The kids who are in school are +not helping on the farm. + +Then there is the need to get +married, which was mentioned + +by Yaprak's sister. + +She says, now I need +to get married. + +And you can be married and +in boarding school. + +In principle you could, but it's +not very frequent that + +you would be both married +and in boarding school. + +So this is not a cost effect. + +This is something which +is more about culture. + +Maybe the husband wants +a young wife. + +Or there is something different +than just a strict + +opportunity cost effect. + +Like, why do they think that +it's important to get married + +early instead of continuing +schooling? + +So these are only important +because they're mentioned. + +And there are the benefits. + +Is it useful? + +Or is it useful only if you +get enough education? + +If it's useful, do parents +know that it is useful? + +What do they expect +of education? + +Do they expect that education +is making their child + +generally better at +living their life? + +I'll do they see +education as-- + +the woman employs a term that +is interesting-- it's almost + +like a foreign currency. + +So people see your education +diploma. + +Do you see that as something +that if you get enough of it, + +you can actually sell +to the market? + +What is enough? + +Is it a foreign currency that +you could get a few cents of + +and that would be good enough? + +Or is it a foreign currency that +you need a big packet of + +to be worthwhile? + +And in the movie, what was +interesting was is that we saw + +different people having +different views about whether + +it is a foreign currency, that +is, you have to take it + +elsewhere to benefit from it? + +Whereas you could also benefit +from it just in your general + +my life, with having fewer, +healthier children, being more + +socialized? + +I think it's again Yaprak +sister who sees another + +advantage of education for girls +in that it is going to + +increase her bargaining power +within the family. + +Since traditionally girls are +quiet and don't say anything + +and men have all the power, and +if girls get education, + +that is going to improve +their bargaining + +power within the family. + +And that is something that girls +may find very attractive + +and their future husbands might +find less attractive. + +And here the question +is what are the + +fathers going to think? + +Yaprak's father, on the one +hand, probably he has in mind + +the value of keeping the +girls in their place. + +On the other hand, he +likes his daughter. + +So there is probably a conflict +within him between + +the fact that as a man, he +doesn't want to conflict with + +his wife, so we would rather +the woman being lower down, + +but as a father probably likes +his daughter more than his son + +in law, who doesn't +even exist yet. + +So there might be a conflict +here in his preferences which + +might easily lead him to say, +fine, she should get an + +education or no, we want +to move forward. + +And what is interesting in the +movie is that he clearly sees + +himself as a bit of a +[INAUDIBLE] leader and a + +modern character. + +So he seemed to have concluded +this debate from his point of + +view to say that OK, +I'll send her. + +AUDIENCE: I have a question. + +I'm wondering with that attitude +if it's sort of like + +we'll just indulge the girls for +a while and let them go to + +school, but we know secretly +that we're still going to take + +the power we have and not +actually concede anything and + +respect the fact that +they [INAUDIBLE]. + +ESTHER DUFLO: Right, so there +might be a little bit of that. + +So just to repeat the question, +the question was, + +are they just indulging them +for a little while and then + +going to bring them +back in line? + +And then education is more +like it's not seen as an + +investment anymore, but more +consumption value for the + +girl, since the government is +providing it for free and + +she's kind of a bit too +young to be really + +helpful in the farm. + +Let's get her get an education, +but we kind of know + +that at the end of the +day, it's not going + +to change her life. + +And we certainly maybe hope that +it's not going to change + +her attitude. + +What's interesting is that if +this is what people had in + +mind is that that's clearly +not her view. + +So that might be a little bit +of disconnect here, which + +would be in her advantage +in terms of when + +she gets the education. + +So here if we're thinking of +these bargaining power issues + +and this potential conflict +withing the father between his + +goal as a husband where he wants +to keep the power, and + +his goal as a father, where he +would like probably her to + +have some power, is that that +may change with economic goals + +in the society and what are the +opportunities he sees for + +her to do something with +the education. + +If the society's completely +paralyzed, then in a way the + +benefits of education are very +high for her, so he has less + +of a reason to want +to go to it. + +AUDIENCE: Just from watching the +video, it seems like it is + +possible for them to combine +both the cultural values and + +the value of education. + +Like for instance, clearly it +is a male-dominated society, + +but here we watch the scenes +where there's a bunch of men, + +sitting around, and +they're talking + +the value of education. + +It's still the women who +are serving them tea + +or whatever it was. + +And they still see the women, +the girl who is getting the + +education, she's still +helping with the + +children and all that. + +So it seems like-- + +ESTHER DUFLO: Yeah, it is +possible that even with the + +education they are still going +to maintain the differences. + +What is interesting is that +there is a level question and + +a slope question, which is it +is possible that the girls + +have so far to go that getting +an education wouldn't be + +sufficient to make them +become equal. + +But that would still go +in that direction. + +And at least some of them seem +to have the hope that it would + +bring it in that direction. + +But you're right. + +So those are the expected +benefits of education. + +And then there is what worries +them about the schools. + +We've mentioned the culturalized +assimilation, the + +fact that it might be like a +covert way to assimilate them + +to a culture that's not theirs, +and the fact that + +maybe there are no benefits, the +fact that just if sending + +the kids away is not +a very good thing. + +Potentially they are +worried about them. + +So these are the +demand issues. + +So the demand issues are a +little bit tricky, because + +depending on how this thing +balances out, what are the + +benefits they see versus the +feel they have versus the + +immediate cost of not having +the kids on the farm. + +Or the decision of sending the +kids or not sending the kids + +is not obvious, even if +education is free. + +And making education compulsory, +of course, pushes + +them in that direction. + +So is benefits of education that +are touched upon in the + +movie are of different kinds. + +There is this foreign currency +idea-- you get a job. + +You get a higher wage. + +They hope that the girl is +going to be a doctor. + +So the issue is can everybody +become a doctor? + +And probably not. + +So even though they don't say +it in the movie, they must + +have in the corner of their mind +that they're not quite + +sure that she's going +to make it. + +They sort of say it, but they're +not quite sure it's + +going to make it. + +And that uncertainty and the +fact that the objective is so + +hard certainly has some impact +in how serious it is to take + +the whole thing. + +And then there is the +possibility that just getting + +an education would help in +your job, doing your job + +better, even if your job +is to be a farmer, + +coming back to the farm. + +And nobody seems to +really say that. + +It's only mentioned in a +negative way, which is if only + +they taught something useful +like home economics then maybe + +we would be able to have some +benefits of this education. + +But that's not what +they are doing. + +And so maybe education is +useless or is seen as being + +useless at the lower level. + +Then there are the non-monetary +dimensions of + +getting an education. + +Girls will become +more socialized. + +The family planning, they'll +have more friends and know how + +to interact with people in +the city, et cetera. + +And then there is the idea of +learning things that you can + +teach others. + +So the one guy who has an +college education in these + +men's discussion, he goes and +say, well, let them get an + +education, come back, and +teach us some stuff. + +And so this is the external +spill-over value of education, + +which is the opposite than the +one that Ben had mentioned, + +which was the education envy. + +But it's the idea that if I get +an education, if there is + +some benefits, for example, +I learn how to read the + +instructions on the fertilizer +package, maybe I learn to use + +new technology in agriculture, +not only it can be useful for + +me, but potentially it can +be useful for others. + +So if that is the case, a +village might decide to focus + +on the smartest kids on the +block and make sure that they + +at least get an education so +that everybody benefits. + +So those are kind of the +benefits of education. + +So one empirical question +is what are the + +real benefits of education? + +The other empirical question is +what are people perceive to + +be the benefits of education? + +Another thing that he touched +upon in the movie is this top + +down versus bottom up. + +So here the government is +trying a big top down + +approach, trying to +do it very fast-- + +putting all the money from the +top, making it compulsory, + +which is the ultimate top +down, and instead of + +supply-drive policy, has been, +as I was saying, popular in + +many countries. + +Many African countries-- + +Kenya, Uganda, Ghana-- + +have recently, relatively +recently, in the last 10 years + +or so, have adopted free primary +education and moving + +to free secondary +education now. + +India, as I was saying, has a +right to education, which + +actually allowed people, in +principle, to sue the + +government if they don't +get a school. + +So the supply drives have been +the main education policy say + +in the last three decades. + +The Millennium Development +Goal specified that every + +child should get at least a +basic education, basic goes to + +nine years of education. + +What is interesting is that +there is no mention anywhere + +that they should actually learn + +anything in those schools. + +It's sort of assumed that if +they get nine years of + +education they'll get +something out of it. + +But as we'll see, it's a +pretty big assumption. + +And there are certainly some +clear signs success of these + +big supply drives. + +Between 1999 and 2006, the +enrollment rates have + +increased, in Sub-Saharan Africa +from 54% to 70%, in + +East and Southeast Asia +from 75% to 88%. + +These are primary +schools only. + +Secondary school enrollments +have also increased, even + +though secondary school is much +more expensive, much more + +difficult to do for +governments. + +So worldwide, there are still +a bunch of millions of kids + +who are not in school, but much +less in 2006 than they + +were in 1999. + +So is it all worthwhile? + +That's the question that +Easterly is asking in the + +reading for today. + +And what is his answer? + +His answer is not that graph. + +AUDIENCE: I thought education +in itself, an increase in + +education, is not going to cause +and increase in growth. + +ESTHER DUFLO: Right. + +He is saying it's useless. + +And how does he explain that +despite the fact that it's + +used less people have +still done it? + +Yeah, go ahead. + +AUDIENCE: [INAUDIBLE]. + +ESTHER DUFLO: Go ahead, +go ahead. + +AUDIENCE: I was going to say +because the increments in the + +[INAUDIBLE]. + +ESTHER DUFLO: Exactly. + +So what Easterly is saying is +that you guys have been fooled + +by this graph. + +These are countries-- + +USA, Romania, Paraguay, +Venezuela. + +And these are the average years +of schooling of the + +population. + +And this is the log output per +worker, relative to the US. + +So everybody is negative because +the US is a richer + +country in the world. + +And what you can see here is +that there is a pretty strong + +correlation between the log +output per worker and the + +years of schooling. + +Countries which have +more years of + +schooling are also richer. + +So one could conclude from there +that year of education + +increases income. + +And people have certainly +drawn this conclusion. + +What is his point about +this graph? + +AUDIENCE: I'm not sure this is +the point but, it's the idea + +of mobility bias. + +We have more education, perhaps +that's because we have + +some sort of mobility. + +I mean, I don't know +if this is-- + +ESTHER DUFLO: This +is countries. + +AUDIENCE: --in the +national sense. + +ESTHER DUFLO: Think of it's like +he made this argument, + +not for a person, but +for a country. + +What's different about these +countries as well? + +AUDIENCE: They also +have more greed. + +Their GDPs are higher, so +they have some more + +opportunity for school. + +ESTHER DUFLO: Yes, +they are more + +flourishing for younger people. + +We run this graph with +the number of + +football team you have. + +You would have a +lot of zeroes. + +It wouldn't be such +a good graph. + +But you would have the same +relationship that places that + +play American football +are also richer. + +And we don't think it's because +of American football. + +Or I mean I don't think so. + +You may have a different view. + +So that correlation is +not very informative. + +So what he's suggesting +is to say, so + +let's not look in levels. + +Let's look in differences. + +And I couldn't find such a +nice looking graph for + +differences, but here is one. + +Now we have the difference in +human capital from it's 1990 + +minus 1965. + +It's a difference in the log +other ideas of education. + +And now we put the log +difference in income. + +You could do it in level log, +except that doesn't matter. + +What's relevant in this graph +is you get a big cloud of + +points and a completely +horizontal line. + +So if I can say this graph in +words, what this is saying is + +that the countries which have +increased the most the average + +years of education of their +labor force, are the countries + +which have put more and +more kids to school + +have not become richer. + +So you compare in the Easterly +reading, he had a comparison + +between different African +countries which had made + +different levels of progress-- + +so I think, so for example, +Ghana versus Madagascar, and + +saying that Ghana has increased +education more, + +Madagascar increased education +more, and Ghana is not going + +faster than Madagascar. + +Actually, I don't think +that's true anymore. + +I think subsequent to that, +Ghana has increased quite good + +and quite a bit faster +than Madagascar. + +But that's, let's say, +was the point, were + +the keys at the time. + +So now we interpret him saying, +well, when we take the + +difference out, now we are at +least seeing what has been the + +effort terms of increasing the +years of education, versus the + +gain in terms of increasing +the GDP. + +And we see no effect. + +So the level relationship was +all coming from this bias In + +fact, there's no effect of +the years of education. + +And the bias in the level of +regression are some form of + +the ability by us as USA which +countries have more education, + +because it takes money +to have teachers. + +They can afford it. + +Or maybe they choose to be +educated because when it's + +more worthwhile to get an +education if you can do + +something with that education. + +So that comes back to this +argument of what's the point + +of getting an education if +you're going to come back to + +the village anyway? + +So if education allows you +to take advantage of the + +opportunities that are afforded +by economic growth, + +then you're going to be more +willing to get an education if + +you think that the country +is going to grow a lot. + +So for all these reasons, and +you would expect more + +education in rich countries, not +because education causes + +growth, but because growths +cause education. + +So his conclusion is that +internationally driven + +investment to education were +a waste, that education is + +actually useless. + +Now there's a bunch of problems +with his argument, + +because in a sense what he is +saying is that I don't see any + +evidence across country that +there is a lot of increase in + +GDP coming from increasing +education. + +But the issue is we don't +know why these + +countries increase education. + +We don't know what would have +happened if they had not + +increased education. + +So for example, many of the +African countries that + +increased education the most +also had severe civil war + +subsequently. + +It is possible that education +caused the civil war, but it's + +not very likely. + +It is more likely that the +social tension that preexisted + +in the country caused +the civil war. + +One possible answer to the +social tension may have been, + +well, let's try and get +people an education. + +Yep? + +AUDIENCE: This is interesting +because I guess in our + +standard macro classes, you +look at a factor of A as a + +multiplicative factor that +increase in GDP. + +And typically, maybe I'm +thinking about it wrong, you + +look at that as if you have +increased education, it could + +be worth more innovation. + +If you have the technology, you +still go for the forms or + +operating a computer. + +And education helps facilitate +that group. + +So I'm a little confused as to +how you make this conjecture. + +ESTHER DUFLO: So that's +an interesting fact. + +I think in a sense, in your +macro class you may have been + +interpreting this graph. + +And there is certainly a lot of +theories for why education + +would be good for growth. + +So one of them is the +one you point out. + +This is the externality argument +that we were making + +about the movie. + +One person who is educated can +figure out some technology, + +and then everybody can +use the technology. + +So they are all these +spill-overs, which is why we + +would get this pretty strong +relationship between education + +and income. + +So there a lot of theoretical +reasons to think that there + +could be a macroeconomic +relationship between education + +and income. + +And in fact, we see one, which +is why everybody is happy + +thinking education +is a good thing. + +What Easterly is saying is just +commenting on this graph, + +which is he doesn't see +a relationship. + +Because when he does, the +relationship in differences + +now between growth and education +and growth and + +income, he doesn't see the +relationship anymore. + +AUDIENCE: How long is that? + +ESTHER DUFLO: That's 1990, 1965, +just about 30 years. + +Yup? + +AUDIENCE: I have a question. + +In Easterly's paper, +he mentions the + +productivity factor. + +And he says that only a small +percentage of this is + +accounted for by [INAUDIBLE] +capital and by machinery and + +other forms of capital. + +What is the rest of it? + +Like, what is productivity +in that case? + +ESTHER DUFLO: So that's +an excellent question. + +The answer to this question is +that's what I do what I do and + +not macroeconomics. + +If you're looking at growth +across country, and you're + +trying to account for the growth +in an pure accounting + +sense, which is to say, so +imagine that you each country + +is a big machine. + +Think of a country +as a machine. + +So there is a machine. + +There are some people to operate +the machine, labor. + +And there is some human capital +to think about how to + +operate the machine. + +And then there is some spunk. + +So think of a macroeconomy +as that. + +In letters, we write it as an A +multiplied by K, that's the + +capital, to some power, multiply +by L to some power, + +multiply by human capital +to some power. + +That's your macroeconomic +model of an income. + +We can observe K +to some extent. + +What's the capital +in the economy? + +We can observe L to a pretty +good extent, how many workers + +there are in the economy. + +We can observe H to some extent, +what is the the human + +capital, usually measured +with education. + +And the rest spunk is what +we don't observe. + +Now we can say, well, let's +look at what share of the + +level of income of the country, +differences in income + +across country, are what share +of differences in growth + +across country are explained +by those factors. + +And the answer is +not very much. + +So the answer is that we use +factors such as capital, + +labor, and human capital, +measured in this way. + +We don't explain much +of the gross + +differences across country. + +This is one of the reasons why, +which when you look at + +growth and you look at the +differences in human capital, + +there's just no relationship. + +There's a bit more with +physical capital. + +And the rest is like, +we don't know. + +So technological progress is +just a fancy term for we have + +no clue what the hell is going +on, which is to me saying that + +well, if we have no clue what +the hell is going on, then it + +means that we need to go beyond +thinking of the economy + +as one big machine. + +And we need to start to +understand what is happening. + +Look at micro level. + +That might start giving us a +sense of what might actually + +be going on. + +Because technological progress +is not just how good is the + +chip in your computer. + +You think of this as, as I was +saying, the spunk, how people + +interact, all of that. + +So in your macro class, you +either saw this graph and + +commented on it, or you may also +seen a graph where you + +have growth on the left hand +side and level of education. + +You do see a strong +relationship + +between growth and level. + +These countries which had more +education in 1965 have grown + +faster between '65 and 1990. + +But what Easterly objects to +that is that yes, of course. + +Because if you anticipate +growth, that's how you're + +going to decide to +get education. + +Because education becomes +more worthwhile. + +So that does not tell me that +education is worth anything. + +So that's where we are +with the macro data. + +And my bottom line is not that +your macro class is wrong or + +that your macro class +is right. + +My bottom line is we just don't +know by just looking at + +these data. + +We don't have enough +data points. + +And anything could +have happened. + +In the countries which were +about to have wars may have + +invested more in education +perhaps as an attempt to not + +have those wars. + +Who knows. + +So in order to answer the +question of what's the + +benefits of education, we need +to look at specific examples. + +So ideally, I would have liked +to look, for you, at the + +example of Turkey, because we +just saw it in the movie. + +But I don't have it. + +So we'll be looking at the +example of Indonesia. + +So if we are looking at the +effect of supply-driven + +expansion, there are some +arguments where one could see + +that it's not going to work. + +And these are arguments that +Easterly is making. + +And we kind of all saw +them in the movie. + +There was the point about +the teacher quality. + +If the teachers don't care +because they've just been spar + +shooted by a central government +to the community + +exactly as you were saying, then +the level of education is + +not going to be very good. + +If the parents don't care and +just do it because they have + +to do it, then they are not +going to put pressure on the + +teachers to actually deliver. + +And they're not going to put +pressure on the children to + +actually learn. + +So the | case is the point that +you were making earlier, + +where the children are all alone +in boarding school, and + +nobody's looking after +what they do. + +And potentially, they learn +nothing, or they might learn + +to do all sorts of bad stuff. + +So if parents do not think that +schools are delivering + +anything useful, then they +won't pay attention. + +And finally, children, +if they also don't + +care, won't pay attention. + +So these are all theoretical +arguments. + +I'm not saying they +are correct. + +But these are the types +of argument + +that Easterly is making. + +So how would we know whether +or not there is + +a benefit of education? + +So as I was saying, I don't +you want to interpret the + +cross-country evidence. + +I think it's very difficult +to interpret. + +So I want to focus on one +country, and this one company + +that did almost the same +thing that Turkey did. + +And fortunately for us, they did +not a few years ago, but + +many years ago. + +So now we can look at those +kids as they are + +in the labor market. + +And we can see whether it was +beneficial for them to be sent + +to these schools. + +So that country is Indonesia. + +Indonesia is an oil-producing +country. + +So when there was a big oil +shock in 1970, starting in + +1973, for Indonesia, it was +actually good news. + +Because there were producing +oil, so they became richer. + +And they decided that they were +going to use this oil + +money to build a +lot of schools. + +Basically, all the oil money the +first few years went into + +building tons of schools. + +Tons means they build almost +62,000 schools + +all over the country. + +But particularly in places +which had a low education + +enrollment. + +So it's your ultimate +top down. + +Furthermore, what is interesting +in relationship + +with Turkey is that they had +exactly the same objective, + +which is they wanted the kids +to learn Bahasa Indonesia. + +That's the language for the +country, even people in the + +outlying island and +stuff like that. + +And they wanted everyone to +learn the state ideology, + +which was the Pancasila. + +It's kind of halfway between +an ideology and a religion + +that [INAUDIBLE] + +was keen on. + +So it was entirely pushed +by public effort. + +If it was going to fail, then +this was going to fail. + +And what do we see? + +So these graphs are the number +of schools that were built in + +the region. + +And this is the difference +between the education of the + +young cohort who benefited from +the school, and education + +of the old guys who +didn't benefit. + +So you see that in general, it's +always positive, because + +education went up over +time between the + +younger and the old. + +That makes sense. + +But it is also increasing in +slope, that is, places which + +got more schools got more +years of education. + +Maybe that's not surprising, +because that's almost a + +mechanical result of +putting schools. + +But this graph is an +interesting one. + +I'm now looking at the wages of +people in 1995, difference + +between the wages of the +young, minus the + +wages of the old. + +Now it's all negative, because +old people have more + +experience and tend to +make more money. + +But what is interesting is +not the negative thing. + +It's the slope again. + +The slope is again positive. + +So it is saying that compared +to the old guys, the young + +people benefit more in places +which build more schools. + +And it's very difficult to think +of a story why would + +this be the case, +except that the + +benefit is from the education. + +So it seems to be the case that +parachuting more schools + +to communities increase +the years of + +education, increase wages. + +And that seems to imply that +education increases wages. + +And in fact, if you put two +and two together, you find + +that the effect of education +on wages is about 8%. + +You can use similar experiments +to look at the + +non-monetary effect +of education. + +So Taiwan around the same time, +little bit before, also + +did a top down drive to +increase education. + +What they did is compulsory +education. + +And what you find in 1968, and +what you'll find is compulsory + +education in Taiwan led to +an increase of education. + +That's not surprising but also +a reduction in infant + +mortality in places +where education + +increased more as a result. + +So again, these are the +non-monetary benefits. + +Nigeria did the same thing +as Indonesia for the + +same type of reasons. + +They used their oil money +to build schools. + +Again, they built more +schools in some + +regions than some others. + +And again you can compare the +changes in infant mortality, + +and infertility, and in wages +in places where they built + +more schools and +in places where + +they built fewer schools. + +And the more schools they +built, the higher the + +education, the higher the +wages, the lower the + +infertilities, the lower +the infant mortalities. + +So the bottom line, when we do +look at specific top down + +policies is that they actually +are useful, that it seems to + +be that there is a returns to +education, corresponding to + +about 8% increase in wages for +every extra year that you + +spend in school. + +So when we look at this thing in +detail and we answer these + +questions, we see yes, there +is a benefit of education. + +What we are going to do next +is to say, well, is the + +benefit as high as +it could be? + +And that's where we are going +to see the limits of these + +kinds of things, having to do +with the quality of education, + +the motivation of the teachers, +the motivation of + +the parents, et cetera, which +we'll do next time. \ No newline at end of file diff --git a/r_fWDSikuNQ.txt b/r_fWDSikuNQ.txt new file mode 100644 index 0000000000000000000000000000000000000000..1ca87f52a7d733fef4a1cc84f06652f815e0ab8c --- /dev/null +++ b/r_fWDSikuNQ.txt @@ -0,0 +1,4175 @@ +The following +content is provided + +under a Creative +Commons license. + +Your support will help MIT +OpenCourseWare continue + +to offer high quality +educational resources for free. + +To make a donation or +view additional materials + +from hundreds of MIT courses, +visit MIT OpenCourseWare + +at ocw.mit.edu. + +PROFESSOR: I have +a tiring day today. + +Just 10 minutes ago, I finished +chairing the first part + +of a meeting of the +COA advisory committee. + +And I gave a talk to them. + +And right after the +lecture, I have to go back. + +So while they have a lunch +break, I have to teach. + +But that's OK. + +That's life on the faculty. + +Yes. + +We're talking about applications +of the spontaneous light force. + +We have used optical +block recreations and such + +to learn about the spontaneous +force, the stimulated force, + +in general. + +And this is our expression for +the spontaneous light force. + +It's pretty much, the +momentum of photons + +is transferred to the atom +times to scattering rate. + +And what we started last class, +and we want to finish today, + +is we want to discuss +applications of this force + +to three situations which are +of experimental importance. + +One can actually say that +slow beams, more or less, + +in the magneto-optical trap +are the key techniques which + +triggered a revolution +in atomic physics. + +This is really the +enabling technology + +into ultracold atom science. + +So I discussed with you, in +the last class, molasses. + +And we discussed +what happens when + +we have two +counterpropagating beams. + +Maybe the key figure to +remember is this one. + +When we have to +counterpropagating beams, + +by just adding up the +spontaneous light force + +of the two beams, we get the red +curve, force versus velocity. + +And the expert eye immediately +sees there is a linear slope. + +And that's a viscous force. + +This is the viscosity of +light interacting with atoms. + +Of course, you'd better +pick the detuning correctly. + +If you use the wrong +detuning, everything + +is flipped upside down. + +And instead of a damping force, +you have an anti-damping force. + +We then discussed +the cooling limit. + +Any cooling limit is the balance +between heating and cooling. + +And by just setting the heating +rate equal to the cooling rate, + +this describes a steady state. + +We found the famous +Doppler limit. + +OK. + +So that's where I +want to continue. + +But do you have any +questions about molasses, + +the Doppler limit, and what we +discussed in the last class? + +Well, I know we had discussions +about to take two beams which + +form a standing wave, and +take it apart, and calculate + +the force for each beam. + +Well, sorry, this is +what molasses is about. + +Molasses is about two beams. + +And if you want to treat +two interfering laser + +beams in the full +generality, there + +are a lot of other effects. + +Some of them, we +will be uncovering + +in the next few lectures. + +But I'm happy now, when +I discuss beam slowing, + +to give you when there +is only one single laser + +beam decelerating atoms. + +That is the only +situation I know + +about where you have an +exact analytic solution. + +So I want to present +it to you know. + +Actually, for a number of years, +I presented the exact solution + +with one laser beam before +I presented molasses, + +where I have to +make approximations. + +But I always felt that beam +slowing is more complicated, + +because you have to go +to a decelerating frame + +and have to add +fictitious forces. + +So some of the +intuition is lost. + +So that's why I first +presented you with molasses, + +with two beams, for which I +need to make approximations. + +Because the interference +pattern between two laser beams + +has richness and complexity. + +But now I discuss +beam slowing with you. + +So this curve here +could be the result + +of the very early beginnings +of laser cooling in + +the late '70s, early '80s. + +And this is when people had an +atomic beam with a Boltzmann + +distribution, and they had one +laser been counterpropagating. + +But the laser beam +had a fixed frequency. + +And what is this +laser beam doing? + +Well, it resonantly +interacts with the atoms + +which just have the +correct Doppler shift + +to be in resonance. + +Those atoms are pushed-- +scattered photons-- are pushed + +to lower frequencies-- +to lower velocities. + +But they are pushed +out of resonance. + +And eventually, the slowing +becomes slower and slower. + +And eventually, things come, +almost, to a standstill. + +So a laser beam which +has a fixed frequency + +would modify the +velocity distribution + +of an atomic beam in that way. + +People called it, +already, cooling. + +And I think some +pioneers in Russia + +who did those experiments were +disappointed that they were not + +honored with a Nobel +Prize in laser cooling. + +This was the first cooling. + +Because this distribution +here is considerably narrower + +than here. + +And temperature is nothing +else than a measure + +of the reach of the +velocity distribution. + +But one can say that +those experiments did not + +trigger a revolution +in atomic physics. + +The revolution came when +people eventually figured out + +how they can narrow down this +peak from maybe a hundred + +or tens of kelvins down +to a million microkelvin. + +So it's clear what is needed. + +If you want to do +more slowing, you + +have to make sure +that you are talking + +to the other velocities, +and that you eventually + +sweep many velocities into one +peak-- clear out the velocity + +distribution, collect +all the atoms, + +and put them at a +monochromatic velocity. + +So for that, you can say, well, +if you use a comb of frequency, + +or a broad spectrum +of frequencies, + +you could clean +out a larger area. + +And, indeed, there +are techniques + +like this-- white light slowing +or diffuse light slowing. + +But since those +techniques are not + +anymore of practical importance, +I don't want to discuss them. + +Let me talk about the +simplest technique-- at least, + +conceptionally-- which +is chirped slowing. + +And this works like follows. + +You start with a laser +beam which is initially + +in resonance with +the velocity group. + +And as the atoms slow down, +you change the detuning + +of the laser that the +laser stays in resonance + +with the atoms. + +So it is a pulsed +technique where + +you have a continuous +atomic beam. + +You start with a laser and +say, now I start slowing. + +And the laser is +following a group of atoms + +as they are decelerated. + +So you can say it is like the +atoms are riding the surf. + +The laser is always +following the atoms + +as they change their velocity. + +And what is, of course, +necessary for that to happen + +is that the chirp and the +deceleration of the atoms + +are synchronized. + +You will see that +in a moment, when + +I put this idea into equations. + +There is another technique +which is used in many labs-- + +actually, in all my labs +and Martin Zwierlein's lab. + +It's called Zeeman slowing. + +And this is discussed +in your homework. + +It is a CW version +of chirped slowing. + +And a lot of you +know what I mean. + +The physics which goes on +there is almost identical. + +But for conceptional +reasons, it's + +easier not to use +magnetic fields and such. + +Let's just keep it simple. + +Let's have one laser beam +talking to a two-level atom. + +And the only other ingredient +is the Doppler shift. + +Any questions about-- +so I've surveyed, + +for you, beam slowing. + +And now I want to give +you the exact description + +for one typical example +of a slowing technique. + +And a lot of the results +we find in chirped slowing + +apply to other +slowing techniques. + +OK. + +I know I've taught +it several times. + +And there is the +conceptional point + +that you can only describe +chirped slowing well + +when you go to the decelerating +frame of the atoms. + +You want to describe it in +the frame of the atoms which + +are continuously +being decelerated. + +So the way I can introduce +it is the following. + +I take the maximum-- I take +the spontaneous light force. + +This is exactly +the expression we + +have discussed several times. + +And now I'm saying +we decide that we + +want to decelerate atoms +with a deceleration, a, which + +is negative, because +we slow them down. + +Of course, if you pick a too +large that it would require + +more than the maximum +spontaneous light force, + +you will not find a solution. + +But let's simply assume we +want to decelerate atoms + +with a deceleration a. + +Well, what happens is +this deceleration, a, + +requires a certain force. + +If the intensity of the laser +would provide more force + +on resonance then it's +not going to work. + +Because we want to decelerate +the atoms at this deceleration. + +So therefore, the atoms, +if they are decelerated, + +have to be at a detuning, +delta prime, in such a way + +that the spontaneous +light force is exactly + +providing the +acceleration we decided + +we want to have for our atoms. + +In other words, this detuning-- +in the frame of the atom, + +the atoms are on resonance +when the light force is exactly + +providing the force to give +you the acceleration a. + +But if you have more laser +power than absolutely necessary, + +in the frame of the +atoms, the atoms + +have to be detuned in +such a way that the force, + +with the detuning, +is exactly providing + +the acceleration we want. + +So that's the easiest +way to explain it. + +We have to set the stage. + +We have to introduce +this nominal detuning. + +OK. + +So you can say that this +detuning is just a definition. + +And now we want to describe +the slowing process. + +So we have said we want +to start with atoms + +at an initial velocity-- which +we'll actually cancel out + +in a moment. + +But let's do it in +a systematic way-- + +and afterwards, we want the +velocity to decrease, linearly, + +in time. + +I simply defined this +parameter, delta prime, + +to be a solution +of this equation. + +So this is a well +defined quantity. + +And the laser detuning-- +which, I've broken my laser + +to change its detuning +as a function of time-- + +is now this nominal detuning +minus the Doppler shift + +due to the velocity +of the atoms. + +I'm really solving the +problem backwards for you. + +I first decide which should +be the velocity trajectory + +of the atoms-- how should +the atoms slow down. + +And then, I define what +is the detuning which + +will result in that. + +That's the easier +way to understand it. + +Of course, if you +pick this detuning, + +the atoms will exactly do that. + +OK. + +But now what we're +doing is the following. + +This is sort of the +acceleration and the velocity + +we want the atom to have. + +But there may be some +atoms in the beam which + +do not have this velocity. + +They deviate from this +velocity with v prime. + +So the goal of +cooling would now be + +to reduce v prime to 0 to +make all the atoms follow + +the trajectory we have +designed for them. + +OK. + +Many words, many definitions. + +Now we can simply +substitute what + +we have defined +into the equation. + +And we get a wonderful result. + +So we take equation +one, which was + +the equation for +the light force. + +And we put all +those definitions, + +which I went to great lengths +to explain to you, into it. + +And we get this result. + +It's just that the detuning has +been expressed by delta prime, + +and the velocity by this +difference velocity v prime. + +It's pure mathematical +substitution. + +But now comes the +important point + +that we want to describe +everything, now, + +in the decelerating frame. + +The atoms are meant to +decelerate with a deceleration + +a. + +And you know, from +classical mechanics, + +if you describe something +in a decelerating frame, + +you have to add a +fictitious force. + +This fictitious force, since +the acceleration is constant, + +is a constant force. + +But I'm expressing it, now, +by the other parameters. + +We've chosen our acceleration. + +We've chosen the +detuning, delta prime, + +that-- everything is +sort of connected. + +And this is just a way to +use the correct-- the most + +easiest units, or the +correct parametrization, + +for this constant force. + +So I have done-- and the +important thing for you + +is, this equation is exact. + +It's exact for an arbitrary +velocity v prime of the atoms. + +So let me just summarize. + +I've taken the +spontaneous light force. + +I've given you a +bunch of definitions, + +what delta prime is. + +That's how you +program your laser. + +But then, in the +decelerating frame, + +we need a fictitious force. + +And this is nothing else than +a mathematically exact rewrite + +of the spontaneous light force +in the decelerating frame. + +But now what happens is-- +we had a decelerating-- + +we had a light force where, +because we assume the laser is + +counterpropagating, +there's a minus sign. + +The fictitious force +has a plus sign. + +And that means that we +can-- and if v prime is 0, + +the force is 0. + +So we can now make a Taylor +expansion for small v prime. + +So we have, again, a viscous +force, a friction force. + +And it turns out that +this friction coefficient + +for beam deceleration is +exactly 1/2 what we got before, + +for molasses. + +But it's clear we +have one laser beam. + +Whereas in molasses, +we had two laser beams. + +If you ask, what is +the heating, well, + +if you have one laser beam +and not two laser beams, + +the heating described by the +momentum diffusion coefficient + +is also just 1/2. + +One beam heats exactly half +of what we got for two beams. + +And therefore, the +temperature, which + +characterizes the width of +the velocity distribution + +in the frame of the +decelerating atoms + +is exactly the Doppler +temperature we had before. + +Because the two +factors of 1/2 cancel. + +So now I have given +you-- and I hope + +you take some pleasure +in it-- an example where + +the laser cooling for +a two-level system + +is exactly described. + +There's only a single beam. + +And the Doppler limit +is the exact solution. + +I've not made any +approximation other + +than assuming I have a +two-level system for which + +the spontaneous light force has +the expression we've derived. + +OK. + +I know, even with +my explanation, + +you have to read through +it once or twice. + +Because I made a +few substitutions. + +And you really have to +digest them at your own pace. + +So let me give you a summary of +what we have done graphically. + +One laser beam scatters light. + +And it is this Lorentzian. + +And it's a negative +Lorentzian because we + +have a counterpropagating beam. + +We push the atoms into +the negative direction, + +they fly in the +positive direction. + +But by going-- by +chirping the laser, + +by going into the +decelerating frame, + +the force doesn't go to 0. + +I had to add an offset. + +And this offset is +the fictitious force + +due to the transformation +of the decelerating frame. + +And now you realize +that this force-- and it + +is the correct force in the +decelerating frame-- has two 0 + +crossings. + +One is a stable point, and +one is an unstable point. + +And the stable point says, if +an atom happens to be too fast, + +it gets a correcting force. + +And this is like a lock point. + +It has a stable lock point. + +All the atoms which did not have +the correct velocity we wanted + +them to have, they are sort of +sucked into this lock point, + +and eventually, will +pile up at a huge peak + +at this nominal velocity. + +And the width of +this peak is simply + +described by the Doppler limit. + +Before I take your +questions, let + +me show you what happens +in the two frames. + +This is v prime. + +This is the velocity in +the decelerating frame. + +And let's say our +initial velocity is this. + +So what happens now is all +the atoms within the atoms + +are decelerated towards +v prime equals 0. + +The friction force puts +them to v prime equals 0. + +But since we are in +a decelerating frame, + +in the absence of the laser, +the whole Maxwell-Boltzmann + +distribution is +just shifted-- not + +because the velocity +of the atoms + +changed-- because we are +in a decelerating frame + +and we are accelerating +away from the atoms. + +And what I just described for +you is the following-- that, + +at v prime equals 0, we +have our friction force. + +And the atomic +distribution in this frame + +is now pushed through. + +And everything which goes +through this resonant region + +is sort of collected. + +And you have a peak which is +piling up at v prime equals 0. + +Probably, it's easier-- +but mathematically, + +I needed the +decelerating frame-- + +if you use the +following picture. + +And just think of this beam +slowing I explained to you. + +If you just switched +on a laser here, + +you would just burn a hole +into the velocity distribution + +and pile up the atoms. + +But now you sweep. + +And when you sweep, you take +the peak, push it further. + +It gets a bigger peak here. + +Push it further. + +So eventually, what +you're doing is, + +by chirping the laser +in the correct way + +with the correct laser +power and all that, + +you're just pushing +the atoms all out. + +And eventually, +they are piled up + +in a narrow distribution which +is defined by the time when you + +just switch off your laser beam. + +So one chirp of the laser, +from an initial detuning + +in the lab frame to a final +detuning in the lab frame, + +will just sweep out the whole +Maxwell-Boltzmann distribution. + +And if you suddenly +switch off the laser, + +you have frozen in a velocity +distribution which is exactly + +described by the Doppler limit. + +So what is easier to +understand-- molasses + +with two beams, or beam +slowing with a single beam? + +I think molasses is +easier, because everything + +happens in the lab frame. + +But think about it. + +It's a nice example for which no +approximations have to be made. + +Questions? + +Yes, Nancy. + +AUDIENCE: It's not +really obvious to me + +how, in this mathematics, +we are choosing + +a time-dependent +detuning as opposed + +to a time-dependent +deceleration. + +PROFESSOR: The way I +presented it logically, we + +said we want a certain +acceleration to happen. + +And then, we provide our laser +that k/kv is the Doppler shift. + +ka is how the Doppler shift +changes as a function of time. + +And we chirp our laser +exactly in frequency + +with a chirp which is ka. + +So in other words, I started +to define a constant a. + +And that would require +that the laser is now + +chirped in a linear way. + +I could have started the +other around and said, hey, + +let's assume we chirp the +laser in a linear way. + +And then, we do +corresponding substitutions. + +And the result +would be the same. + +AUDIENCE: No, actually, +like if we did not + +want to have a detuning +which was time-dependent, + +would we have gotten-- +we still have a force. + +And that force would +have been just changing. + +PROFESSOR: Well then, it's +more complicated, yeah. + +Then, you have to integrate +a differential equation. + +But what happened +is the following. + +What I've done is, by defining +the acceleration and then + +the chirp, I have the situation +that, in the reference + +frame of the decelerating +atoms, the detuning is constant. + +So usually, you go to +a decelerating frame + +if something else simplifies. + +And what simplifies is that, +in the frame of the atom, + +the laser detuning is constant. + +So you can also say the frame +in which the atoms decelerate is + +exactly the frame in which +the chirp has disappeared. + +Because the decelerating +frame compensates + +the chirp with a +linearly varying, + +time varying Doppler shift. + +OK. + +But the physics, I +think, is really-- + +the moment you have a force +which has a 0 crossing, + +it's a lock point. + +You determine the slope. + +And alpha, together with +the momentum diffusion, + +gives you the final temperature. + +So I hope you enjoy that it's +actually the same physics-- + +exactly the same +physics-- we discussed, + +with some approximation +for molasses. + +OK. + +We had a discussion last time +about, we have the force, + +we find exactly what +happens to the atoms. + +But we may have to think +about it in different ways + +to figure out where the +kinetic energy goes from. + +And I think we mentioned it +already, in the last class, + +that what happens is you have +a red-detuned laser, which is, + +the photons are absorbed. + +But the atom is scattering +light in all directions. + +And so if you go +at 90 degrees, you + +don't have a linear +Doppler shift. + +If you go forward-backward +with the same probability-- + +a symmetric pattern-- the +Doppler shift averages to 0. + +So on average, you emit +photons which are on resonance. + +And therefore, every time +you scatter a photon, + +you radiate away +the energy which + +is equal to the Doppler shift. + +That means, initially, when +the Doppler shift is huge, + +each photon transports +away a lot of energy. + +And the slower the atoms +are, the less a photon + +transports away. + +But that makes sense. + +If you have a huge +velocity and you + +subtract h bar k, the +momentum of the photon, + +the kinetic energy is +quadratic in velocity. + +You know, h bar k, the +momentum transfer of a photon, + +takes out more kinetic +energy the faster + +the velocity of the atoms is. + +So everything makes +sense and is consistent. + +OK. + +Let's go from the-- we +started with two beams. + +We just discussed one +beam, chirped slowing. + +And let's go now to what most +of you use in the laboratory-- + +namely, six beams. + +You want to cool in x, y, z. + +So you have +one-dimensional molasses + +with two beams times 3. + +So in the limit that +the intensity is low, + +you just add up all the forces. + +You say each beam has a +spontaneous light force. + +And you add the six +spontaneous light forces up. + +At low intensity-- and you +have to take my word for it-- + +you can ignore all the +interference effect + +between the beams. + +They can actually lead to +very interesting effects. + +I will give you at least a taste +of what will happen-- actually, + +a pretty good taste-- what +happens at higher power. + +We need the traced atom picture. + +And we'll discuss how +the stimulated force + +can be used for cooling. + +But if you don't have +a two-level system, + +you have sigma plus +sigma minus transitions + +and the beams interfere, you get +spatially varying polarizations + +of your interference +patterns, and then you + +have much [INAUDIBLE] physics. + +But in the simplest case +of a two-level system, + +there is a regime +at low intensity + +where you can simply take the +equations we got for molasses + +and apply them to XYZ. + +I put, on the website, a nice +handout, a review paper by Bill + +Phillips, who is discussing 1D +molasses versus 3D molasses, + +and if you enjoy +it, you can read + +how numerical factors +of 1 or 2 or 3 + +now appear in the +friction coefficient, + +in the heating +coefficient, and how + +they affect the +final temperature. + +But you got the full [INAUDIBLE] +concepts and the correct idea + +for one dimension molasses. + +Now, let me give you +an outlook for what + +we will be doing next week. + +Next week, we want to +understand the following-- what + +happens to the +friction coefficient + +when you increase the power? + +Well, you remember when +we have red-detuned light, + +then we had one Lorentzian, +another Lorentzian. + +The slope was +negative, and negative + +means positive +friction, we cool. + +And if you put +more power into it, + +the linear slope increases, +and for low power, + +the friction coefficient is +proportional to the laser + +intensity. + +But now look what happens. + +If you approach saturation, +then the friction + +is not only saturating, it +suddenly changes the sign, + +and this is qualitatively new. + +And you should a little +bit wonder about it. + +Wasn't the reason why we +have cooling that you have + +a laser which is red-detuned? + +And the photon which is +spontaneously emitted + +is on resonance, and this +is the energy difference. + +But now I'm telling +you, at high intensity, + +it's not the red-detuned +laser which cools, + +it's the blue-detuned laser. + +So you should wonder about it. + +There is really something +new to be learned. + +So I want to motivate you to +follow me today and next week + +through an alternative +description + +of what light does to atoms +using the dressed atom picture, + +and in the dressed +atom picture, we + +will very naturally +understand why + +now blue-detuned light +provides cooling. + +But right now, for you, +this should be a mystery, + +but it should be something +where you say, hey, + +still something +qualitative is missing + +in our understanding +of light forces. + +OK, I will not be +able to explain + +it [? physically ?] to you. + +I first have to introduce +the dressed atom picture, + +and I will do that it +in 10 minutes or so. + +But what I want to do +here is if I'm telling you + +something goes terribly +wrong and we completely + +miss even the sign of the +force, blue-detuned light is now + +cooling, not red-detuned +light, I at least + +want to tell you +what went wrong. + +Because haven't we done +an almost exact discussion + +of light forces? + +We used the gradient of d dot e. + +We used for d the steady state +solution of the optical Bloch + +equations. + +Haven't we done +everything right? + +Well, we did approximations. + +And what happens is, +and this is the reason + +for those qualitatively +different things, that we + +should, in order to get +those effects, not use, + +for the dipole moment, for the +off-diagonal matrix elements + +of the density matrix, +the steady state solution + +for optical Bloch vector. + +We have to acknowledge that +it always takes a finite time + +to reach steady state. + +For instance, if he takes, let's +say, a spontaneous emission + +time, if the atom goes +through a standing wave, + +it goes from high +intensity to low intensity, + +it takes about one +spontaneous emission time. + +When you are highly +excited, but now you + +go through a node of +the standing wave, + +the steady state +solution is [INAUDIBLE]. + +At the node of the standing +wave, there is no light. + +The steady state +solution with no light + +is you better go back +to the ground state, + +but that takes +something on the order + +of the spontaneous +emission time. + +So therefore, when I +am excited because I'm + +in the middle of the +[? pied ?] laser beam + +and I go fast into +the dark region, + +I'm still excited because +I didn't have time + +to get rid of my excitation. + +In other words, the +internal degree of freedom, + +the population of +grounded excited state, + +will lag behind the +steady state solution + +by a lag time which is a +spontaneous emission time. + +And that would mean if I +multiply with the velocity, + +it's pretty much that there +is a spacial displacement. + +I'm always a certain distance +away from the steady state + +solution. + +And actually, this point, +to introduce the lag time, + +we with do it in a +wonderful, physical way when + +we have the dressed +atom picture, + +but it can be done with +optical Bloch equation. + +It's just a real pain because +the optical Bloch equation + +is sort of like a +matrix the equation. + +It's completely +obscure, how it is done, + +but in order that you +convince yourself, + +I posted the original paper +from Gordon and Ashkin + +where this was done. + +You read the math. + +You understand the +result, but you + +don't understand the derivation, +the physical picture behind it. + +The dressed atom picture will +give us a lucid explanation + +for exactly what a +lag time does and why + +this results in colling. + +But anyway, this is the +physics we have done wrong. + +At low power, it's OK. + +At high power, we really +have to take care of effect. + +And if we would take care +of effect-- And as I said, + +we don't need the +dressed atom picture, + +we can fully do it within the +framework of the optical Bloch + +equation, but it's messy. + +--we would actually get out, and +you see that in the references, + +the result that the friction +coefficient in a standing wave + +at weak power is exactly two +times the friction coefficient + +for a travelling wave, and +that justifies that we describe + +molasses by the spontaneous +light force of two travelling + +waves, completely ignoring +the standing wave. + +But the same treatment of +the optical Bloch equation + +will then, eventually, +give us the result + +that alpha changes +sign at high intensity. + +But as I said, I +want to describe + +that after we have introduced +the dressed atom picture. + +Questions? + +OK, we have done molasses +in one dimension. + +We have done beam slowing. + +We just did a short +discussion about molasses + +in arbitrary dimensions. + +The one technique +which is missing now + +is the magneto-optic trap. + +Let me just spend five +minutes to discuss + +the background behind +the magneto-optic trap + +because for many of you, +I think you were just + +born when the magneto-optic +trap was invented. + +Well, I joined +the field in 1990, + +and that was three years +after the magneto-optic trap + +has been invented. + +And many people say if there is +one most singular development + +in laser cooling and +such, it's molasses + +and the magneto-optical trap. + +So let me tell you why, +the magneto-optical trap, + +you shouldn't take +it for granted. + +It was actually in +1983 that Ashkin-- + +Was it Gordon or Ashkin? + +I think Ashkin, Art Ashkin. + +--that he presented an +Optical Earnshaw theorem, + +and it is nicely described +in Bill Phillips' Varenna + +notes which I have +posted on the website. + +And it's pretty much a proof +that you cannot build a trap + +using the spontaneous +light force. + +So in other words, +this is a proof + +which people took +as a correct proof + +that something like +the magneto-optic trap + +could not exist. + +So what this is proof like? + +Well, and that +sort of teaches you + +what was the mental concept +or the mental barrier people + +had to break through +before they invented + +the magneto-optic trap. + +The proof is the following. + +If you think that you +have beams-- I mean, + +a model for the spontaneous +light force is you have photons + +and the photons are +sand blasting the atom. + +Each photon is like +a grain of sand, + +and the atom is in scattering +descent in all directions. + +You can really make this +completely classical picture + +of the spontaneous light force. + +Almost. + +If you do with that you would +say the spontaneous light force + +is proportional to +the stream of photons + +which is described by +the Poynting vector. + +But now, you have +in electromagnetism + +a continuity equation which says +the divergence of the Poynting + +vector plus the change of energy +density in a certain volume + +has to be 0. + +So if you are in +steady state-- If you + +have an arrangement +of laser beams + +and the energy density of +the electromagnetic field + +is at steady state, +that tells you + +that the divergence of the +Poynting vector has to be 0. + +Well, if the divergence +of the Poynting vector + +is 0, using this +equation that says + +the divergence of the +spontaneous light force + +has to be 0. + +But if the divergence +of the force + +has to be 0, that means you +can not have a force which + +is inward from all directions +because such a force, + +a trap needs a force +which is inward. + +A trap requires a +negative divergence. + +Do you see the wrong +assumption in this proof, + +or did I convince you that +the magneto-optic trap is not + +possible because this +proof would say you can not + +make a trap out of the +spontaneous light force? + +AUDIENCE: Well, you through out +the change in energy density, + +so that's-- + +PROFESSOR: But that's +OK because if you switch + +on a laser beam, light +travels at the speed of light, + +and in 10 to the minus 10 +seconds, in picoseconds, + +you reach steady state. + +And you know when +you operate the MOT, + +you're not switching on and +off your lasers at picoseconds. + +It's not that. + +Yes, [INAUDIBLE]. + +AUDIENCE: --the +spacial variation of c. + +PROFESSOR: Yes, exactly. + +The force is not just +proportional to the Poynting + +vector. + +This would be true if +I had grains of sand, + +but photons have to fill +a resonance condition. + +You can maybe +assume I'm an atom, + +but I have an spatially varying +magnetic field around me. + +At the one magnetic +field, I feel the force + +of the laser beam +because I am resonant. + +At another magnetic +field, the laser beam + +just goes through me because +I'm not in resonance. + +So therefore, the +proportionality + +between the Poynting +vector of the laser + +beam and the light force +ignores that the light force + +is resonant, that the +light force depends + +on polarization and such. + +So the solution +is the divergence + +of-- If the c parameter +is spatially dependent, + +then we can have a divergence, +and then, we can do trapping. + +And it was actually Dave +Pritchard in '85 or in '86 + +who wrote a really +influential paper. + +He said the Optical Earnshaw +theorem can be circumvented. + +We can have a spatially +dependent factor, + +and what can be spatially +dependent is saturation. + +If you focus a laser beam, +you have a spatially varying + +saturation parameter. + +There can be some +optical pumping. + +There can be light-- + +So he discussed +several possibilities + +how the Optical Earnshaw +theorem was circumvented. + +At this point in 1986, +he didn't realize + +that it can be done with +a magnetic field gradient. + +When he talked about possible +ways of circumventing + +the Optical Earnshaw theorem, +Jean Dalibard, who many of who + +know, who's a famous +researcher in our field, + +had the idea that applying +a magnetic field gradient + +could work. + +But nobody thought, +at this time, + +that it would work +in three dimensions, + +so the fact that it +works in three dimensions + +is almost a miracle. + +So when the idea was born, +all those schemes, and also + +the original idea of applying +a magnetic field gradient, + +were conceived as +one dimension scheme. + +Most of the schemes can +not be easily generalized + +to three dimension, +but the MOT scheme + +works as well in three dimension +as it works in one dimension. + +Anyway, so this is +sort of the background. + +Since I was a postdoc +when there were only two + +or three groups who were +operating a magneto-optic trap, + +I put together, +with my own hands, + +the first magneto-optic trap +which was ever used at MIT. + +I mean, it's ancient +history, so I + +wanted to share a little +bit this history to you. + +But let me now simply +describe to you + +how the magneto-optic +trap works. + +Let me describe it +for an atom which + +we are not using in the lab. + +We all usually use atoms which +have hyperfine structure. + +But let me just for +pedagogical simplicity + +assume that we have an atom +which has an s to p transition, + +and in the p transition, +we have the three different + +magnetic [? quantum ?] numbers. + +So it's a simplified model. + +And what we're +doing right now is + +we are applying molasses, two +beams which act as molasses, + +but there is one difference now. + +They have different +polarizations, sigma plus + +and sigma minus, +and in addition, we + +apply a linear magnetic +field gradient. + +So what happens now +is the following. + +The linear magnetic +field gradient + +does Zeeman shifts in +the opposite direction + +to the n plus 1 and +n minus 1 level. + +Now, the transition to m minus +1 is done by sigma plus light. + +The transition to m plus 1 +is done by sigma minus light. + +So what happens now +is if you have an atom + +and it moves away +from the origin, + +it will eventually come +closer and closer in resonance + +with the sigma plus light, +but the sigma plus light + +comes from the left side so +the atom will be pushed back. + +If the atom moves out hear, it +moves further and further away, + +in resonance, from +the sigma plus light, + +but it moves now, in resonance, +over the sigma minus light, + +and the sigma minus light +is pushing the atoms back. + +So this geometry has an inward +force from both directions + +and therefore, works as a trap. + +So let me now describe +it mathematically + +which is very, very simple. + +What we have to do is we +just have, like in molasses, + +two laser beams two +times the expression + +for the spontaneous light force. + +And you'll remember we +got the molasses equation + +by taking the two laser beams +and putting in the Doppler + +shift which is a +velocity dependent shift. + +Well, all we have to do is, +for those two laser beams, + +we have to put now a spatially +dependent Zeeman shift which + +varies linearly with position. + +So therefore, all we have to +do is we sum up the total force + +as the spontaneous +force for the right + +and for the left laser +beam, and in addition + +to the molasses effect, we put +now in the spatial dependence. + +So we don't have to +do the math again. + +We did already a +Taylor expansion in v, + +but let's now just +do a Taylor expansion + +in the blue expression. + +And then, we find that there +is a linearly restoring force + +both in velocity space and +in configuration space which + +actually tells you +something interesting. + +The more friction you have, the +larger is the restoring force. + +So the trapping and the +cooling are really connected, + +at least in the simple model +of the spontaneous light force. + +OK, so if we have +this kind of force, + +a linear force in velocity, +a linear force in position, + +this is the equation of +motion of a damped harmonic + +oscillator. + +You have a spatial +force constant, k, + +this linear force which +is linear in displacement. + +So this is a damped +harmonic oscillator. + +Usually, you don't +see atoms sloshing + +in your magneto-optic trap +like in an harmonic oscillator + +because if you look through +the [? typical ?] numbers + +and by just doing +the Taylor expansion + +of the spontaneous light +force, you can immediately + +get an alluded expressions +for those numbers. + +In almost all cases, +the harmonic oscillator + +is overdamped. + +So that's how the +magneto-optic trap works. + +However, the magneto-optic +trap is not so simple. + +I would actually +say nobody fully + +understands the +magneto-optic trap + +because we have +multi-level structure. + +We don't have just +one count level. + +A sodium and a +rubidium atom has-- + +f equals one and f equals two-- +has eight different hyperfine + +levels. + +So there is not one level +and we can excite the atoms. + +There are eight +different levels. + +And those laser beams to optical +pumping among those eight + +levels, and you have to +solve a rate equation + +for eight different levels. + +And the amazing thing +is it still works. + +It still works +pretty much, at least + +qualitatively, as well as +I just described to you. + +So it's a combination of optical +pumping and Zeeman shifts. + +It even works better +than advertised + +because as I will tell +you in the next few weeks, + +you can reach +temperatures-- Because + +of the multi-level +structure, you + +reach temperatures which are +much colder than the Doppler + +limit. + +It's called polarization +gradient cooling. + +It's just if you +have laser beams + +and you have atoms with +hyperfine structure, + +they are colder than +the Doppler limit. + +First, nobody understood +it, and then, Bill Phillips + +figured it out. + +And that he figured +out why atoms + +get colder that +was the main point + +emphasized by the +Nobel Committee + +when he got the Nobel +Prize for laser cooling. + +Of course, he had already +invented Zeeman slowing before, + +so he had a few other +things under his belt. + +But anyway, the fact +that the MOT works + +even better than advertised +is another miracle, + +and this is related to +the hyperfine structure. + +And finally, the fact that +you can simply extended it + +to three dimension, is-- I said +the first, the second --maybe + +the third miracle. + +It also works. + +Because when you +look at the field + +of two coils, a so-called +Anti-Helmholtz field, + +there are some directions +where the magnetic field is not + +radially outward. + +This is a much more +complicated magnetic field. + +It goes outward +here, outward here, + +but in between the quadrupolar +field, it sort of curves. + +There are some directions +where the magnetic field is not + +radial, and you would say, hey, +the one dimensional scheme is + +[INAUDIBLE] [? set. ?] + +Actually, before the +magneto-optic trap + +was demonstrated, Dave +Pritchard's student, + +Eric [? Rob ?] did +calculations what + +happens in these +diagonal directions which + +have no resemblance to +the one dimension scheme. + +The solution is in +those directions, + +the trapping form is +a little bit weaker, + +but the big picture +is it doesn't matter. + +So there was an idea +conceived in one dimension + +for a simple atom structure, +and this idea worked even better + +for real atoms and +in three dimensions. + +OK, in your homework +assignment, you + +will put in some +numbers which show + +what happens if you take +a vapor, an alkali vapor + +at a very low density of 10 +to the 8 per cubic centimeter, + +pressure of, typically, 10 +to the minus 8 [? Tor, ?] + +and you arrange six +laser beams around it. + +Well, those laser beams have +a restoring force in velocity. + +That means they cool and +increase the phase space + +density over your sample +by 8 orders of magnitude. + +Those laser beams have +also a restoring force + +in the spatial dimension. + +Therefore, you get +a cloud which has + +3 orders of magnitude +higher density. + +So the temperature goes down +by 8 orders of magnitude + +which means the phase +space density is enhanced + +by 12 orders of magnitude. + +So if you're talking +about the goal of reaching + +Bose-Einstein condensation +which requires a phase space + +density of 1, just +having a dilute vapor + +and these six laser beams with +a little bit of magnetic field, + +increases your +phase space density + +by 15 orders of magnitude. + +So this is why molasses and +the MOT were a real milestone. + +Now, with 15 orders +of magnitude, + +you are just 4 or 5 +orders of magnitude + +from Bose-Einstein +condensation, and we + +will discuss, in +a week and a half, + +what techniques were +needed to bridge + +the gap between those +temperatures and densities + +and quantum +degeneracy of gasses. + +So that's the story of +the magneto-optic trap. + +I'm also telling +you that because I'm + +proud that a lot of the +pioneering work in this regard + +happened at MIT. + +It was Dave Pritchard who +realized at the Optical + +Earnshaw theorem +can be circumvented, + +and it was him, in a +collaboration with Steve Chu, + +that they together realized +the first magneto-optic trap, + +and this was in 1987. + +Questions? + +OK, I think simple applications +of the spontaneous light force. + +So we have time to talk +about the dressed atom. + +Now, I was waiting +until this point + +to introduce the dressed +atom picture for you + +because the dressed atom picture +is the natural picture you want + +to think about, for instance, +for the Mollow triplet, + +and we had already some +discussion about it. + +But it is also the +natural picture + +you want to think about +it when you describe + +the stimulated light force. + +And I mentioned already, it is +the dressed atom picture which + +will help me to give you the +physical picture behind if you + +have strong laser beams, +why blue-detuned light cools + +and not red-detuned light. + +So you should be motivated now +to learn about the dressed atom + +picture. + +But first, I have +to say it's not + +anything new, what +I'm teaching you. + +It has exactly the +same physics in it + +as the optical Bloch equations. + +It's just that the optical +Bloch equations are + +often more complicated, +and they don't + +provide the clear insight. + +And the reason is the following. + +Often when you describe +a physical phenomenon, + +you can choose one basis set, or +you can use another basis set. + +But if you're in +the wrong basis, + +you get the correct results, +but in the wrong basis, + +you just can't describe +the physics easily. + +So in other words, with +the dressed atom picture, + +I want to introduce dressed +atom states for you which + +are no longer the ground +state and the excited state. + +I want to treat the +atoms dressed up + +by the laser beam, +which is one mode + +of the electromagnetic field. + +So the atoms, together +with this one laser beam, + +will be partially excited, +partially in the ground state. + +And this partially +excited atoms, this + +is the dressed atom basis. + +But if you think in +terms of those states, + +you have a much easier +way to formulate + +certain physical processes, +exactly processes + +where you have high laser power. + +At low laser power, +the dress states + +are identical to +the naked states + +to the ground and +excited states. + +But at high laser power, +at infinite laser power, + +the two dressed states are the +symmetric and anti-symmetric + +equal superposition of +grounded and excited state. + +So that's what we +want to describe now. + +So the difference to the +Optical Bloch Equation + +is that we are +now really looking + +for the combined +state of the atom + +in the electromagnetic field. + +So what we want to do is-- +this is sort of our picture + +that we have. + +This is our Hamiltonian. + +We have the atom +interacting with the vacuum + +through spontaneous +emission with a reservoir + +of empty modes. + +But now, it also interacts +with the laser beam. + +And you remember when we +did the master equation, + +we looked sort of at this. + +We derived a master +equation for this. + +And then we added +in the unitary time + +evolution due to laser beam. + +But what we want to +do now is we want + +to first take care of the +atom and the laser beam + +almost exactly in an +exact diagonalization. + +And once we have +re-diagonalized that, + +we have now eigenstates which +we call the dressed states. + +Then we allow not the +ground and excited state. + +We then allow the dressed +states to emit into the vacuum. + +And this is the formulation +we want to obtain now. + +Let me make one +comment before I go + +through a few simple equation, +and that's the following. + +If I want to treat this +system almost exactly, + +I have two choices. + +I use a strong laser beam. + +So I could, as we have +discussed several times, + +simply use the time dependent +external electric field. + +The laser beam is E0 +times cosine omega t. + +And I just introduced +that in the Hamiltonian. + +And you can get +everything I describe now + +for you out of this Hamiltonian. + +However, there is +an alternative way. + +And this one is I simply +assume that the laser beam is + +described by the +fully quantized field. + +And I use the fog state. + +I just assume N, the number +of photons, is very big. + +And this is, at least +for that purpose, + +a valid description +of the laser beam. + +So what happens is you really +want to look through that. + +I've really learned +a lot by comparing + +the purely classical +treatment of the laser beam + +and the fully quantized +description of the laser beam. + +The results are the same. + +They are Absolutely identical. + +And what you will see is, by +a bunch of approximations, + +we reduce the total +Hamiltonian to-- I've + +seen it many times-- +a two by two matrix. + +And whether you start +with the classical field + +or whether you start with +the fully quantized field, + +if you make the +right approximation, + +you get the same +two by two matrix. + +But there's a difference. + +This Hamiltonian is +time independent. + +a dagger a, time +independent Hamiltonian. + +If you take a classical field, +which is cosine omega lt, + +you don't have a time +independent Hamiltonian. + +You have a driven system, +and your wave function + +has an external time dependence. + +The laser beam is driving +the wave function. + +So in other words, +you have two choices + +when you want to describe +how an atom interacts + +with a strong laser beam. + +You can use the fully quantized +field, which is conceptionally + +a little bit more +complicated, because we've + +quantized the +electromagnetic field. + +But then everything +is time independent, + +and everything I do +here is really easy. + +I can go over it +now in five minutes, + +and you understand everything. + +Well, in your +homework, I've already + +asked you at an early homework +to look at simply the two level + +system driven by +classical field. + +And in your next homework, +number 10, your last homework, + +I'm asking you now to +interpret the solution + +with the classical field. + +And it's actually a +little bit a challenge + +to take the time +dependent wave function + +and read the physics out of this +time dependent wave function, + +which corresponds to the physics +we derive in the dressed atom + +picture. + +But you have two ways. + +One is the classical field. + +Then the wave function, the +Hamiltonian, is time dependent. + +And the wave function +is time dependent. + +Or here, I start with +the quantum field + +and everything is +time independent. + +But the solutions are identical. + +Well, one is a time +dependent wave function. + +One is time independent. + +But if you interpret +the solution + +in terms of what happens +to the physical system, + +you will find exactly the same. + +So in other words, I decided +I do the easy part here, + +which is a fully quantized part. + +And this is probably what +will get stuck in your head. + +But since I think it's an +important pedagogical exercise, + +you have to go +through the homework + +and do the time dependent part. + +OK, so we want to +know exactly-- well + +not-- we want to do the +correct approximations. + +And after some +approximations, exactly + +solve what the atom does +with one laser beam. + +So the laser beam is described +by the standard Hamiltonian + +for single mode light. + +The atom is described by, well, +excitation energy omega 0. + +And b is the excited state. + +So if you don't have any +light atom interaction, + +the eigenstates are just product +states, an atom in the excited + +or the ground state. + +And N is the photon number. + +[? Collin? ?] + +AUDIENCE: You said that +it's usually easier + +to understand physics +in a dressed atom + +picture versus optical +block equations. + +PROFESSOR: Yeah. + +AUDIENCE: Can you think +of-- is that a general rule? + +Or is this just like it's only +applicable in certain areas? + +[INAUDIBLE]? + +PROFESSOR: You're really +asking an expert question. + +And I talked to Jean Dalibard +and Claude Cohen-Tannoudji, + +who invented the dressed +atom picture, when + +I wanted to understand +what happens when + +we have a blue detuned lattice. + +And I used the dressed atom +picture and I got confused. + +So what happened +is the following. + +If you pick your right bases, +the description is simple. + +But simple means +if all the physics + +is your atom is in +one dressed state + +or the other dressed state, +and it does transitions + +between the dressed +states and that is easy, + +and this happens in the +limit of large detuning. + +But if you're in +the regime where + +coherences between the +dressed states matter. + +In other words, the density +matrix in the dressed state + +basis has now off +diagonal matrix element. + +The physics becomes +complicated again. + +So in other words, what +I'm telling you is you + +are the best description +happens when we have a two level + +system, we always need +a two by two matrix. + +But if you pick the description +where the solution is diagonal, + +if you have to deal with +coherence, using coherence + +is coupled to population, +it's complicated. + +And there's some cases-- one is +the blue detuned lattice, which + +I encounter where you have to +consider the coherences to get + +the correct answer. + +And usually, also when +the laser beams are weak + +and on resonance, the +dressed atom picture + +is not providing any advantages. + +So you want to use the bare +picture for weak excitations. + +And yes, in the resonance +case, the dressed atom picture, + +if you're very +close to resonance, + +the dressed atom picture +gets more complicated. + +But to give you the answer in +something we have discussed, + +you know already that when +you drive an atom with a laser + +beam, you get the +Mollow triplet. + +And the Mollow +triplet shows you-- + +I hope we can finish that +today-- shows you the energy + +splitting between the +dressed energy levels, + +between the dressed +energy levels. + +But if the Mollow +triplet is not resolved + +because the generalized +Rabi frequency is small, + +then you're not resolving +your dressed atom levels. + +And then the dressed +atom level is not + +providing a big advantage. + +For certain problems, +the dressed atom picture + +will not help you. + +But I can reassure +you, and this is + +what I learned from +Jean Dalibard and Claude + +Cohen-Tannoudji, +if you really look + +at the full matrix with the +off diagonal matrix append + +and everything, you will always +find exactly the same solution. + +Anyway, we were +just writing down + +product states of the atoms +and the eigenfunctions + +of the Hamiltonian +for the light, which + +are fog states, number +states with N, L N plus 1. + +But the important thing +is now the following. + +In the limit of small +detuning, the ground state + +with N plus 1 photon is almost +degenerate with the excited + +state with N photons. + +And we call these two +states a manifold. + +The manifold E of N. And +N is the photon number + +in the excited state. + +So what happens is, if you +look at all those states, + +they are grouped into manifolds. + +And the energy separation +between two manifolds + +is, of course, I go from N to N +plus 1, the energy of a photon. + +So now I introduce the +atom laser coupling + +in the usual dipole +approximation. + +And what happens is, this +dipole approximation, + +this dipole light atom coupling +will couple, of course, + +ground and excited state. + +And it will, of course, +have a big effect + +when the energy +splitting is small. + +Well, you will see +that in the next line. + +But we have the co and +counter rotating terms. + +This dipole Hamiltonian will +also couple the ground state + +to the excited state +in the other manifold. + +This is the off resonant +term, which will be neglect. + +So here are the +equations for that. + +Our electric field is, of +course, a plus a dagger. + +The dipole operator is that. + +And if you take what is in +front of the electric field + +and define this as the +coupling constant, g, + +we have what I just told +you, that within a manifold, + +the ground state +with N plus 1 photons + +is coupled to the excited +state with N photons. + +g is simply the +coupling constant, + +which all parameters have +been included in that. + +But then, because of the matrix +element of a or a dagger, + +we have the square +root of N plus 1. + +OK, so what we are now doing is +we are going with this coupling + +within a manifold, which +is strong because the two + +levels are energetically close. + +And we will neglect the +non-resonant couplings + +to the other manifolds. + +And that's just another +way of doing, again, + +the rotating wave approximation. + +Now, when we describe an atom +in the laser field and the atom + +scatters light, or +we have a laser beam, + +and I have to tell you, +when we have a laser beam, + +we don't provide exactly +N atom, N photons. + +The laser beam is +in a coherent state. + +And there are +Poissonian fluctuations. + +But now, we do the next +approximation, namely we + +say when N is +large, then delta N + +can be neglected +with regard to N. + +Then at least for the +range of important photon + +numbers for the problem, this +coupling becomes independent + +of N. And we simply take the +average number of photons + +in our laser beam and define +now an electric field, which + +is independent of N. + +And the product with +the dipole operator + +of the atom, that's what +we call the Rabi frequency. + +So at that point, we introduce +a classical electric field + +through this definition, and +therefore, the dressed atom + +picture. + +Also, we start with the fully +quantized Hamiltonian is now + +identical to the classical +field with this electric field + +amplitude. + +But what we have gained is +we could discuss everything + +in a time independent picture. + +And now, I promised you, +we'll go back to a two + +by two matrix, which you +have seen many times. + +It's a two level system. + +We have the detuning. + +We are in the rotating frame. + +So that means the ground and +excited state with N and N + +minus 1 photons have +the same energy. + +But if we have a detuning, +there is a difference + +whether we excite the +atom or whether we + +put a photon in the laser field. + +But you have seen +that many, many times. + +And the coupling +is now described + +by the Rabi frequency. + +So that's kind of +our typical two level + +system where the two levels +[INAUDIBLE] the rotating frame, + +everything is time independent. + +The two levels are split, +and they are coupled. + +And well, how many times have +you seen the solution of two + +by two matrix? + +The solution is that +the coupling is now + +increasing the splitting. + +The splitting between +the two levels + +is, again, the generalized +Rabi frequency, + +which you have seen +many, many times. + +But now we want to really +get the wave function. + +We want to get something out +of the dressed atom picture. + +And that's the following. + +We started out with the +bare states-- ground + +state with N plus 1, excited +state with N photons. + +And the two by two matrix +after the diagonalization + +is now a linear +combination of those. + +And it's convenient to use +sine theta, cosine theta, + +because then the states are +automatically normalized. + +If I introduce the +solution is now + +that the angle theta is +given by this equation, + +that's just the solution +for the two by two matrix. + +And the physical picture, +which we have obtained, + +is the following. + +If this here is the energy +of the excited state with N + +photons, I've just sort of drawn +this as a reference parallel. + +But now I want to draw it +as a function of the laser + +frequency. + +Well, the ground state +with N plus 1 photons + +has exactly the same +energy on resonance. + +But if the photon is more +energetic then this state, + +because it has N plus 1 +photons versus n photons + +if the photon is more energetic +than a resonant photon, + +this state has higher energy. + +And here, it has lower energy. + +In other words, we +have now a level + +crossing between +the two bare states. + +But a level crossing +with interaction + +turns into an avoided crossing. + +And the solution which +we have just derived + +are the blue curves. + +And if I go far +away from resonance, + +this behavior here, +which is perturbative, + +is nothing else than +the AC Stark shift. + +So this is exactly what we +have discussed at this point. + +Now, let's get some +mileage out of it. + +And we will talk +about light forces. + +That's really interesting. + +And I hope it's another +highlight of this course + +to describe light forces in +the dressed atom picture. + +But what I want to +do here is already + +in preparation for that. + +I want to not yet +introduce forces, simply + +figure out what happens in +the dressed atom picture + +when the atoms scatter light. + +And you know already +the solution. + +The solution is +the Mollow triplet. + +And we have discussed with +the Optical Bloch Equations + +that at low laser power, +the Mollow triplet + +has three curves. + +It has three broadened curves. + +And they have +different broadening. + +And I didn't prove it to +you, but I mentioned to you, + +at low laser power there is-- +perturbative laser power, + +we discussed at great length +that there's a delta function. + +And at low laser power, +the delta function remains. + +So this is sort of the +spectrum we get out of it. + +And what I want +to show you now is + +how this spectrum is described +in the dressed atom picture. + +Atom photon interaction +has a wonderful discussion + +of all the details. + +I will share with +you a few highlights. + +But we will go much further in +the description of the Mollow + +triplet then we've gone before. + +But I will not go into +all excruciating details. + +So let's discuss first. + +That's something we +hadn't done so far. + +What are the intensities +in this Mollow triplet? + +So the way how we obtain +it is the following. + +We have the manifold, the +manifold with N minus 1 + +and the manifold with N photons. + +And this is the detuning. + +And if we allow for the +atom laser coupling, + +the splitting here is a +generalized Rabi frequency. + +And well, you immediately see +that in this picture, if you + +allow spontaneous emission from +the upper manifold to the lower + +manifold, you have four +different combinations. + +One is the long photon +is the blue sideband. + +This is the red sideband. + +This is the blue sideband. + +This is the red sideband. + +And those two are the carriers. + +But now, we can +do the following. + +I've just written down for +you the solution of the wave + +function with sine +and cosine theta. + +If we want to emit the blue +sideband, we go from the top + +to the bottom. + +But that means, since a +photon in the rotating wave + +approximation can only be +emitted when we go from b to a, + +we find that the +matrix element for that + +involves cosine theta +times sine theta. + +However, if you want +to emit the carrier, + +you go from here to there. + +Well, we always have to find +the excited state to begin with. + +And we go-- I must +have made a mistake. + +Sorry. + +When I went to emit +the blue side, when + +I go from all the way +up to all the way down, + +and I always have to find +an excited state which + +connects to the ground state. + +And this gives me a term, +which is cosine square. + +The red detuned sideband +gives me sine squared. + +And if I want to get +the carrier, this one, + +I go from here to here. + +I get cosine theta sine theta. + +So in other words, +we can immediately + +read off the matrix elements. + +And since the intensity, +Fermi's Golden Rule, + +is the matrix +element squared, we + +find immediately that the upper +lower sideband and the carrier + +involve terms cosine to the +4 theta, sine to the 4 theta, + +cosine square sine square. + +So we got the matrix element. + +And the only thing +we have to know now + +is that the width or the rate +is given by the matrix element. + +The rate is given by the +matrix element square. + +But now, what is the +intensity of the line? + +Well, the upper +sideband is emitted + +by the upper dressed +state, because you + +have to go from the +upper dressed state + +to the lower dressed state to +get the blue detuned photon. + +So therefore, the +intensity for this sideband + +is this rate times +the population + +in the upper dressed state. + +So what is missing +at this point, + +and we need that urgently +for next week, what + +is the population in the +upper and the lower sideband? + +Well, we know the +transition rates + +between the upper and +the lower sidebands-- + +well, between the upper +and lower dressed state. + +We know we've just +found here the rate. + +What is the rate? + +What is the matrix element +squared when you go from one + +is the upper, two is the +lower state of the manifold. + +So we have just +gotten those rates. + +And rate equation says, +the change of population + +in the upper dressed +state is given + +by the departure +from the upper state + +and what arrives +from the lower state. + +So since we are interested +in the steady state solution, + +we can just set the +left side to zero. + +And then, the rate +equations simply + +give us the population +in terms of the rates. + +So in other words, if you +ask, what is the steady state + +solution in the upper +or lower dressed state, + +it's given by a ratio of +those rate coefficients. + +But we just got those +rate coefficients. + +And this gives us another bunch +of sine and cosine functions. + +So in other words, +we know now what + +is the population of +the dressed states. + +I mean, everything is expressed +by one non-trivial parameter + +theta. + +And all we get is sine square, +cosine square, sine to the 4th, + +we just get those +trigonometric functions. + +Yes. + +I think we can finish that. + +Good. + +So this is the steady +state solution. + +But now, we can go back +to the rate equation + +and say the time derivative +of the rate equation + +has to relax to +the steady state. + +This is nothing else than +rewriting the equation above. + +But by rewriting the +equation above in that way, + +we find now the +prefactor in front of-- I + +mean, here, what you have is +the time derivative is given + +by the difference +from steady state. + +And this is the +relaxation coefficient. + +And the relaxation coefficient +is-- that's the solution. + +You just have to do the +substitutions yourself. + +The relaxation coefficient, +how populations + +relax to steady +state, is now given + +by the sum of the two rates. + +One is going from the +upper to the lower + +and from the lower +to the upper state. + +And each of those rates +has been expressed + +by sine square and +cosine squares. + +I'm not doing it here, +because it's a little bit more + +complicated. + +But you can also rewrite for +the dressed atom picture what + +happens-- you can rewrite those +equations in a way what happens + +not to the population, but +what happens to the coherences, + +to the off diagram +matrix element formulated + +in the dressed state basis. + +And what you find is, you find +a correlation time, a relaxation + +time, for the coherences. + +Remember, for the naked +state, population's + +relaxed with gamma. + +Coherence is relaxed +with gamma over 2. + +This is for the Optical +Bloch Equations. + +But now we have reformulated +the physics in the dressed atom + +picture. + +And what the solution +is the following. + +This is sort of a +weak laser power. + +But in the most general +case, what you will find + +is that the width +of the central peak + +reflects the relaxation +time for the population. + +And the width for the sidebands +is the relaxation time + +for the coherences in +the dressed atom picture. + +So we had before with the +Optical Bloch Equations, + +I showed you different cases. + +We had a three quarter gamma. + +I need two more minutes and +I'm finished with my unit. + +So we had weird factors +of three quarters. + +And I showed you how they +come from the eigenvalues + +of the matrix of the +Optical Bloch Equation. + +But now we understand +them physically, + +namely the central +feature has a peak, + +which is the relaxation +time for the populations + +in the dressed atom picture. + +And the sidebands +have a width, which + +is the relaxation time +for the coherences. + +They no longer differ +by a factor of two, + +as in the naked bases in which +we formulated the Optical Bloch + +Equations. + +By the way, I know +a lot of you may + +be curious about +the coherent peak. + +You can read about it in API. + +It's 10 pages about +correlation function. + +But in the end, the rate +of the delta function + +can be, again, described by +values we have just calculated. + +We have just calculated +steady state populations + +and transition rates. + +So this rate is nothing else +than another combination + +of sine square and cosine +squares of this angle theta. + +So everything is wonderfully +and simply described + +the full physics of +that by just this angle + +theta in the dressed +atom picture. + +OK So with that, we are done. + +And I think I'll discuss the +last page with you on Monday. \ No newline at end of file diff --git a/raP-0nqnF_A.txt b/raP-0nqnF_A.txt new file mode 100644 index 0000000000000000000000000000000000000000..2ea37a52a5d189371e40f0c81e962f20c64352d9 --- /dev/null +++ b/raP-0nqnF_A.txt @@ -0,0 +1,3184 @@ +The following content is +provided under a Creative + +Commons license. + +Your support will help +MIT OpenCourseWare + +continue to offer high quality +educational resources for free. + +To make a donation or to +view additional materials + +from hundreds of MIT courses, +visit MIT OpenCourseWare + +at ocw.mit.edu. + +PROFESSOR: So last time we +talked about how to describe + +say for the boundary CFT is at +a finite temperature what would + +be its gravity description? + +So what we described +was a thermal theory. + +Say a Thermal CFT on +the flat space, OK? + +We show that this is related +to a black hole with a planar + +horizon. + +The key is that the horizon +should have the same topology + +as the boundary space. + +So in terms of the picture +this is your boundary, + +so this is z equal to 0, and +then the horizon somewhere say, + +at some value of z0. + +So horizon has some value +of z0 and then the horizon + +have the same topology +as the boundary on space. + +And then you can do some of +the [? lamicks, ?] et cetera. + +Any questions about that? + +Good. + +So previously we also +briefly discussed + +that the Ads also allow +you to put the field + +theory on the sphere. + +So if you put the field +theory on the sphere + +then that will be due +to the global Ads. + +Now you can ask +the same question. + +What happens if we put the +boundary theory on the sphere + +and then put there the +finite temperature. + +So let us put a +CFT on the sphere + +at the finite temperature. + +So the story here is much +richer for a very simple reason. + +For a very simple reason. + +So if you have a CFT just on the +Rd minus 1 so this Rd minus 1, + +this euclidean space, +euclidean flat space + +does not have a scale and the +CFT does not have a scale. + +So if you put it at +a finite temperature + +then the temperature +is the only scale, + +and essentially provide +a unit over the scale. + +So the temperature +is the only scale, + +so essentially providing +an energy unit. + +So this means that for CFT on +the finite temperature, CFT, + +on the flat space then +physics at all temperatures + +are the same. + +So they are just related +by a scaling of units. + +So in some sense you can see it +seems that the physics is very + +simple whether you +have like 0.0001 degree + +or you have 10,000 +degrees, doesn't matter. + +And it's only the relative +scale that matters. + +So the physics at all +temperatures is the same. + +There's no difference +between the low temperature + +and the high temperature, +and the temperature just + +provide the units. + +But if you put the +CFT on the sphere + +now the story's different. + +So for CFT on the sphere because +the sphere has a side itself. + +OK, so let's take the +sphere have both sides r. + +Again when you put +the CFT on the sphere + +the sides of the sphere does +not matter because again + +the sides of the +sphere are essentially + +provide by the units because the +theory's getting [? warrant. ?] + +So let's just put all +the sides to be r. + +So let's take sides to be r. + +And the r can be +chosen to be the same + +as the curvature radius +in the [? back ?] + +just to make formula +simple, and you + +can choose it to be any radius. + +And now since the sphere +already have [? all ?] sides + +and now you put it at +a finite temperature. + +Now you have the +dimensionless number. + +Then at the finite +temperature in the physics + +is controlled by a +dimensionless number, r times t. + +So now the temperature +makes a difference. + +Now different +temperature that r is + +is different because now +you have a relative scale + +and if rt is small +then essentially you're + +at the low temperature, +and then when rt is big + +then you have a +high temperature. + +Now there's a +dimensionless number + +to characterize whether +you're in the low temperature + +or in the high temperature. + +So the physics essentially +become much richer because + +of the and then you have a +you have a whole parameter + +the physics can depend on. + +And so indeed the story +become rather intricate + +whether we can see +the finite temperature + +theory on the sphere +so now let me just + +mention some important features. + +So I will walk you not too +slowly but also not too quickly + +about the physics on the sphere. + +We cannot afford to do it +very slowly at this time. + +Yeah, but if I do +it too quickly, + +of course you won't +learn anything. + +OK, so let me just point +out some important features. + +So first, when we +talked about the story + +last week-- when we talked +about the finite temperature + +on the flat space-- we +said, oh, probably there + +are two possible descriptions +for finite temperature + +theory from the +[? back ?] point of view. + +So one is that you can +have a thermal gas. + +You have a thermal gas in Ads. + +But then we argue +that for a theory + +on the sphere that's +not allowed because you + +encompass singularity because +the metric becomes singular. + +And the one big difference +for the theory on the sphere + +is that actually +now this is allowed. + +So the thermal gas in +Ads is now allowed. + +So now let's go +through the argument. + +So now first let me just write +down the global Ads metric. + +Of course you can write in +many different coordinates. + +So the most +convenient coordinates + +to write global Ads for our +purpose is the following. + +So this is just a pure Ads +and r goes to 0 to infinite. + +So this is like somewhat +analog of a, say, + +sprinkle coordinate +in flat space. + +But the difference +is of course now + +you have nontrivial +factors which tell + +you're in the curve space time. + +So now to go to +the thermal Ads we + +do the trick you normally +do for thermal field theory. + +Is that you go to +euclidean space + +and then you put +the euclidean time + +to be periodic in the +inverse temperature. + +Actually, let me write +down here the analogous + +metric on the sphere. + +So this is a situation +we can see that + +before for the theory on the +flat space, on the plane, + +and then that would be the +metric to be on the sphere. + +So we've talked about +last time if you + +make tau to be +periodic then as z + +goes to infinity then this +circle shrink to zero sides. + +Because the prefactor goes to 0. + +So the tau circle +will have a sides beta + +but the proper densities +controlled by the prefactor. + +And because when z goes to +infinity then the proper lens + +of the circle goes to 0. + +So whenever you have a +circle we shrink to 0 + +then you have a singular +behavior, et cetera, + +and then the metric's singular. + +So you can have [? where ?] +it is a singular behavior + +and so that's why this +is not the amount. + +But now in this case, when you +do such energy configuration + +this becomes well defined. + +Because of the proper sides +of the tau circle so now you + +local proper lens local proper +sides over the tau circle, + +it's just given by +this prefactor 1 plus + +r squared divided by 1 +squared by r squared beta. + +And since a greater +equal here so + +this is greater equal to beta. + +So actually this is +bounded from below. + +So this is a circle [? label ?] +will become too small. + +Essentially the minimal +side of the circle + +is the same as the beta itself. + +So this euclidean metric +is perfectly well defined. + +OK, so euclidean +metric well defined. + +So you can trust here that the +euclidean metric is singular + +as z goes to infinity. + +If you put the 0 in +the flat space then + +that's not allowed but +in this case allowed. + +So for the serial +in the sphere-- + +but still there's an analog +of a black hole solution. + +You can also find +the black hole. + +Again you just write +down the standards, + +sprinkle's metric answers, +for black hole metric + +and then you solve +Einstein equation, + +then you find-- so let me +just write down the answer. + +So you find that this space also +allows a black hole solution. + +Can be written as the following. + +So now f just slight +generalization of this factor. + +So the mu is primarily +related to black hole mass. + +And the horizon is that +i equal to r0 and r + +satisfy that this +factor goes to 0. + +So you can also find out what +is temperature associated + +with this black hole. + +So here that beta +can be anything. + +There's no constraint +on the beta. + +So here using the standard +technique to find what + +is the Hawking temperature +for this black hole. + +Let me just write +down the answer. + +So this is just 4 pi +divided by f prime. + +You've already add to the +horizon standard formula + +and you just find +the 0 of this guy, + +and then you just +take the derivative + +so you find the beta can +be written in terms of r0 + +as follows. + +So this is just +a simple algebra. + +So you find that if you +take the derivative, + +we express the +derivative is r0, then + +you find the Hawking temperature +of the following form. + +I'm not doing this +calculation here. + +You can use it to +check yourself. + +Good, any questions so far? + +So now it seems like +we have a problem. + +Because we have a +black hole we also + +have a standard thermal Ads. + +Then which one is +the right description + +for the field theory at +the finite temperature? + +Seems like we have a choice. + +But now if you look +at this function + +the story's even more +tricky than that. + +So this product of this function +this is a rough behavior + +of this function. + +So this is the +inverse temperature + +and then this is the +sides of the horizon. + +And the side of the +horizon essentially + +determines your entropy. + +So it's really a +physical thing here + +and because of the area over +the horizon it's the entropy. + +The area of the +horizon is a entropy. + +So this r0 it can be considered +as something standard + +for entropy. + +So now just to +get the intrusion, + +this is a complicated +function, it's + +because intrusion and +how this beta depend + +on this r0, the horizon side. + +Suppose horizon side is +very small, r0 goes to 0, + +then downstairs is finite. + +Upstairs goes to 0 +so you just go to 0. + +And the r0 is very +large so the downstairs + +proportionate to r0 +square but upstairs only + +proportionate to r0 so +when r0 is very large + +we go to 0 as the r0. + +And this is a small +function so there + +must be a maximum somewhere. + +And because you can easily +find the maximum just + +to take the derivative +of that function. + +Anyway, so that's how the +beta will depend on r. + +But now this plot +is highly peculiar. + +Why? + +Can you tell me why? + +There's a maximum on +theta, which means? + +That's right. + +So there's a beta max. + +So that means this is a beta +max which tells you there's + +a minimum temperature. + +That means that black +hole solution only + +exist above a certain +minimal temperature. + +And you can easily find out +what is that minimal temperature + +just by taking the +derivative of this function + +and it require to be 0. + +Is there any other thing +peculiar regarding this plot? + +AUDIENCE: When r0-- + +PROFESSOR: Hmm? + +AUDIENCE: When r0, +[INAUDIBLE] black hole. + +PROFESSOR: Well, r0 is +0-- the black hole becomes + +smaller and smaller. + +It means there's no black hole. + +AUDIENCE: But the +temperature is infinity. + +PROFESSOR: Hmm? + +AUDIENCE: But the temperature +there is infinity. + +That's weird. + +PROFESSOR: No, that's not weird. + +No, that's the standard, +the flat space black hole + +behaves that way. + +Just look at a Schwarzschild +black hole in flat space + +when the horizon side +becomes smaller and smaller + +the temperature become +higher and higher. + +That's a standard +feature of flat space. + +AUDIENCE: It must +be the other way. + +If you have a huge +black hole, then why + +is it that the beta goes down? + +That seems bizarre. + +Maybe it can't also +be standard, right? + +[LAUGHTER] + +PROFESSOR: Both things you said +are correct and are important + +but there's something +more elementary + +you're not pointing out. + +You're pointing out the higher +order of important things. + +But there's one lower order +important thing that which + +is not yet pointed out. + +AUDIENCE: There +are two solutions + +of the same temperature. + +PROFESSOR: Exactly. + +In terms of the temperature +this is a [INAUDIBLE] + +So if you look at +the given temperature + +they're actually two solutions. + +So for any given temperature +there are two solutions. + +Say T greater than +T min so this is + +for the beta smaller +than beta max + +means that T greater than T +min There are two solutions. + +And then we have to +label them so let's + +very imaginatively call this +one the big black hole and then + +this one the small black hole. + +Because this one have a +larger size and this one + +has a smaller size. + +So this corresponding +to the r0 of those two. + +So you have two +black hole solutions. + +One have a larger radius +than the other one. + +So we have big black hole +and a small black hole. + +And now this is +an important thing + +you mentioned that for +the small black hole + +the temperature when +you decrease the sides + +the beta decrease. + +That then means the +temperature increases. + +So this as I said +it's like an entropy. + +So if you lower +the entropy somehow + +your temperature increases. + +So when you increase +the temperature + +you actually lower the entropy +for the small black hole. + +A small black hole +you go like this. + +Go like this. + +When you reduce the sides, +you reduce the beta, + +means you increase +the temperature. + +But this is actually the +standard Schwarzschild black + +hole behavior in flat space. + +And this just tells you have +[? a lack ?] of specific heat. + +So this is a situation +we understand. + +This is a situation +we can come up + +with a flat space, a +Schwarzchild black hole. + +And it make sense why it's +happening here because here + +roughly is order r. + +Because the r is +the scale here so + +the maximum location where the +maximum is controlled by the r. + +So this region corresponding +to sides of the black hole + +to be much, much smaller +than Ads curvature radius. + +So when something +is much smaller + +than the curvature +radius what you do see? + +Hmm? + +AUDIENCE: [INAUDIBLE] + +PROFESSOR: Yeah, flat space. + +Yeah, it just like even though +we live in the curved universe + +but we actually see flat space +because of course our scale + +is much more than curvature +radius of universe. + +And a similar key thing here +even though the black hole + +have a size much smaller than +the curvature radius of Ads + +they essentially behave +like flat space black hole. + +And so that's exactly what +you see for the flat space + +black hole. + +And indeed, in a +more interesting + +is this big black hole, +the [? interesting ?] + +is a big black hole. + +And the big black hole when +r0 increases the temperature + +increase. + +So this is the right way. + +So this is indeed the standard, +just positive specific heat. + +You can check it has +positive specific heat. + +So this is indeed what you'd +expect from a thermal system. + +And so this is indeed what you +expect from a thermal system. + +So now we are encountering +an even weirder situation. + +We not only have so more ideas. + +We're not only have black hole. + +We actually have +two black holes. + +So what's actually described +with the field theory + +at finite temperature? + +So what does this really mean? + +Number two is a +black hole solution. + +Now let's look at +the number three. + +So now let's look at +what are the indications + +those solutions. + +So first thing you +can just guess. + +So what do you think what these +three solutions should mean? + +If you believe this, +duality has to be true. + +Yes, so that the +game we play here + +is that you believe that +the duality is always true. + +And then whenever you see some +phenomenon, the gravity side, + +you say this, I +try to integrate. + +I try to understand on +the field theory side. + +And it makes sense and then +we just carry out the guess + +and check it, et cetera. + +So what would the +three solution mean? + +Three gravity solutions, or +in principle for example, + +for a temperature at here +we can have three solutions + +all have the same temperature. + +What would this mean? + +So the simplest guess +is that it tells you + +that for CFT and the ST +minus y at this temperature + +there's three possible phases. + +There's three possible phases. + +It's just like +water, ice, or vapor. + +There's three possible phases. + +Now, the interpretation +is clear. + +Then we should just find. + +So to decide what is +the right solution then + +we should find what? + +That's right, we +should find the phase, + +find the one with the +lowest free energy. + +And then to decide which +is the right one then + +we just need to find the one +with the lowest free energy. + +So now recall that the partition +function the field theory + +side should always be +identified with the partition + +function on the gravity side. + +And then this side the +partition function by definition + +is minus beta, the free energy. + +[? Seems ?] like +going more and more. + +that's weird. + +But on the gravity +side we write this + +by saddle-point approximation. + +We integrate over +all possible field + +on the gravity side weighted +by the euclidean action, + +and the leading order in the +saddle-point approximation + +you just evaluate it. + +You just evaluate it on +the classical solutions. + +So now you can just equate them. + +You just need the +free energy must + +be equal to se to +the to the [? Ic. ?] + +So this is just the same +principle we discussed before + +on how we just apply it. + +So now if we believe +the duality and we + +believe with some of +the [? lamicks ?] then + +we should just find the +solution with now just SE. + +So we should calculate the +euclidean action for all three + +solutions and then we find +the corresponding free energy + +for each of them, and then +the one with the largest, SE, + +will correspond to the one +with lowest free energy. + +Then that will be +the stable solution. + +And the other phases presumably +will be unstable or not stable. + +just like in the standard story. + +So this conclusion was drawn +from some of the [? lamrick ?] + +itself. + +But what will be nice we can +actually draw this conclusion + +without using thermal dynamics. + +So we say, so this +[INAUDIBLE] was + +drawn to identify this +with the free energy + +and then we say according +to the sum of dynamics, + +and then we should choose the +one with the lowest energy. + +But will be better +if you can actually + +derive this thing +from the gravity side, + +and you can and for +a very simple reason. + +So this also follows +from the standard rules + +of saddle-point +approximation as follows. + +Oh, I forgot to +write on this board. + +So when you evaluate +this [? possible ?] + +so when you evaluate +your integral + +you're in the saddle-point +approximation, + +so normally you are instructed +to add the contribution + +of all saddle points. + +So the fact that you have +three different solutions + +it tells you have three +separate saddle points. + +And then just from +the standard rule + +of the saddle-point +approximation + +you just need to add +all of them together. + +So you add the expression SE, +you evaluate the thermal Ads. + +And the expression, +SE you evaluate it + +as a big black hole, +and then you add the SE + +to the small black +hole, et cetera. + +OK, you add all +of them together. + +And now each action +is in exponential. + +And as I said, +they are weighted. + +All this action are +weighted by n square. + +Because the action is +always proponent to law + +of [? Newton ?] and the law of +newton is [? proponent ?] to n + +square. + +So there's a big parameter +in the exponential. + +So the saddle is not just SE +dominates in the large N limit. + +You just add three +exponentials, which one + +is the biggest will dominate. + +Because each one of them is +proponent to n square and n + +goes to infinity. + +And n goes infinite means it's +greater than the other guy + +by a tiny bit. + +in the prefactor of n squared +they will become predominant. + +So we see that the sum of +the [? lammicks. ?] Sum + +of the [? lammicks tells ?] us +we should define the smallest + +free energy and then that +statement can be essentially + +derived if I don't +know that statement. + +I can actually derive that +rule, say finding the smallest + +free energy, just by using +the standard saddle-point + +approximation from +the gravity side. + +So this is a nice +consistency check. + +This a nice consistent +check that the duality + +which we believe to be +true should be true. + +Yes? + +AUDIENCE: So the one thing +I don't totally understand + +is that, so say that you +give me this Euclidean + +integral over metrics +on the gravity side. + +So the idea that there's really +only three contributions-- + +because we found three solutions +with a particular temperature-- + +how do we know that there +aren't any other solutions? + +Like, how do we know there +aren't any other terms that + +were not accounted for? + +PROFESSOR: Oh yeah, +there are three-- + +so this is a rule of the +saddle-point approximation, + +you find the saddle-point. + +So you find the solution +of the equation of motion + +with the right boundary +conditions and these + +are the only ones. + +Yeah, and then of +course, each of them + +include the fluctuations. + +This is just the standard +saddle-point approximation. + +Any other questions? + +So now the task just +boils down to-- yeah, + +let me just emphasize +here-- yeah, + +so now, the task just +boils down to find + +what is the lowest free energy. + +OK? + +So now it's 3-- no, it's 4. + +So now, let's try to decide +which one is more stable. + +So first, let me just emphasize +SE is proportional to the 1 + +Newton-- 1/G Newton. + +And then it's always +proportional to N squared. + +OK? + +Because 1/G Newton is +proportional to N squared + +if you translate from +the [INAUDIBLE] language. + +And now, if you vary the +free energy for them-- + +for this-- here let me call +this-- thermal [? gas and ?] + +AdS, I always just call +it TAdS, OK, Thermal AdS. + +I think, yeah, just-- the +shorthand is just thermal AdS. + +So for the thermal AdS, +this is actually 0. + +This is actually 0. + +So thermal AdS is the free +energy-- I should say this way. + +SE is actually the +0 times N squared. + +And then you can have +fluctuations then + +that can contribute to the +order and to the power 0 + +[? contribution ?]. + +So the 0 in this-- 0 is simple. + +It is because, when we go +from the [? pure ?] AdS + +into the thermal +AdS, essentially + +we just changing the +global structure. + +OK? + +We just make the Euclidean +circle so for the pure AdS, + +when you go to Euclidean space, +the tau have infinite size. + +And then when you go +to the thermal AdS, + +we just make the tau +to be a compact circle. + +So you have not changed the-- +the solution is identical. + +The solution is identical +go to the pure AdS. + +Just the global structure +is different in terms + +of the periodicity of the +Euclidean time circle. + +So now, if you vary +the classical action-- + +so if you're reference +point is that the pure AdS, + +the classical action is 0. + +And then, for the +thermal AdS will be 0. + +OK? + +Will be the same. + +It would be the same-- +the classical action will + +be the same as pure AdS, OK? + +So [INAUDIBLE] order N +squared, but then you + +can have fluctuations +which contribute. + +And the fluctuations +is to the-- yeah, + +so the fluctuations +can be interpreted + +as the, say, the graviton +symbol [? and ?] division + +from the symbol, graviton gas. + +OK? + +And so, say, in the +themal AdS sites + +essentially, have a +thermal gas graviton. + +And there, free energy +is independent of N + +because they are +the fluctuations. + +And just as usual, +whenever you can + +see that the fluctuations +there, they're + +independent of a +coupling constant. + +Is this clear? + +AUDIENCE: Why is +the first term 0? + +PROFESSOR: Hm? + +AUDIENCE: Why is +the first term 0? + +PROFESSOR: The first +term is 0 because this + +has the same classical +solution as the pure AdS. + +AUDIENCE: The pure AdS, then, +has a nonzero [INAUDIBLE]. + +PROFESSOR: Yeah. + +Yeah, that's a +very good question. + +AUDIENCE: [INAUDIBLE] + +PROFESSOR: Yeah. + +I will-- yeah. + +Wait a few minutes. + +I will talk about +this more precisely. + +It's a good question. + +AUDIENCE: Oh, OK. + +PROFESSOR: Yeah. + +Let me just tell you +the answer first, + +and then I will +say a few things. + +Any other questions? + +OK. + +And then if you calculated +the Euclidean action + +for the big black hole +and the small black hole, + +you find that they are +always greater than that. + +It's always larger than action +for the small black hole. + +And this is some number, nonzero +number, times order N squared. + +So this is always the case. + +We also [INAUDIBLE] way for you +to calculate in a few minutes. + +But I will not do this +explicit calculation here + +because it takes some time. + +So there is a simple +way, physical way, + +to understand this-- to +understand why this is true + +because this is a free energy. + +So this tells that the free +energy of the big black hole + +is always much more-- is always +smaller than the free energy + +of the small black hole. + +This is not a precise +way to understand it, + +but it is a heuristic way-- is +that if you look at these two + +solutions-- so these +two solutions have + +the same temperature, +but the big black hole + +have a larger size. + +When you have a larger +size and the entropy + +is proportional to the +area of the horizon-- + +and the entropy is much +higher, so the big black hole + +has much higher entropy +than the small black hole. + +And so you choose-- you +would expect that this should + +have a smaller free energy. + +But, of course, you have +to do a precise calculation + +to really check it because +their energy is not the same. + +Their energy is +also not the same. + +Yeah, but this is a +heuristic way to understand. + +Anyway, so you find +that the free energy-- + +so you find the Euclidean +action, or the [INAUDIBLE], + +is always much-- +is always greater + +than the small black hole. + +And that is good. + +That is good because +that tells you + +the small back hole +is never dominate + +because you always find +something bigger than that. + +And the small black hole have +a [? lack of ?] specific heat. + +That's not something you +want because our Field + +Theory definitely have +quality of specific heat. + +Our Field Theory definitely +has quality of specific heat. + +So that tells you +that this is never-- + +can be low-- that would +be a dominate phase. + +So now, if you +calculated a number-- + +so now if you look at +the number explicitly-- + +So what you'd find actually-- +so you also have-- let me just + +first tell you the results, OK? + +You find there exists +a temperature, Tc, + +which is greater than +the minimal temperature. + +Then, you find that the-- when +you're smaller than the minimal + +temperature-- + +Yeah. + +Right. + +OK. + +So when your T is smaller +than the minimal temperature-- + +oh, no. + +No. + +T is smaller than Tc. + +So you find that there +exists a Tc, which is greater + +than the minimal temperature. + +So let me just say this. + +So when T is smaller than +T minimum, of course, + +there's only thermal AdS exists. + +And, of course, that +would be the only phase + +which can describe the +Field Theory result. + +But, now, there exists another +temperature [? then, ?] + +within T, smaller than-- +greater than T minimum + +and smaller than Tc. + +Then, you find that the SE big +black hole is smaller than 0. + +And the thermal +AdS, essentially, + +by definition to be 0. + +So that means that +the thermal AdS + +will have lower free energy. + +So in this range, the +thermal AdS will dominate. + +And when T is greater +than Tc, then you + +find that the big black hole +now has a positive action + +and [INAUDIBLE] dominates. + +So if I draw this-- +and then there's a Tc + +and there's a T minimum-- so +this is the temperature axis. + +So here, of course, you +only have a thermal AdS. + +But within this +range, the thermal AdS + +dominates over big black hole +and the small black hole. + +And when you're above, then +the big black hole dominates. + +So you actually have +a transition at Tc. + +So below here, it's +just thermal AdS. + +And then you have a +transition from thermal AdS + +to the big black hole at Tc. + +So a quick side remark. + +How we-- how would +you find this result? + +So this would be the result +if you calculated the-- so + +you just calculate +the Euclidean action. + +You compare them. + +That's what you would find. + +So any questions about that? + +Yes? + +AUDIENCE: Do you ever get +the small black hole phase + +at all somehow artificially? + +PROFESSOR: Yeah, you can +always get artificially. + +Yeah, artificially, always. + +Yeah. + +And let me not go into that. + +So now, let me just say a few +remarks, say, in finding SE. + +So when you find the +Euclidean action, + +you find it is always divergent. + +It's the same thing as +what we encountered before. + +If you calculate +the whole action, + +you have to integrate the-- +over the-- essentially, + +the volume of the AdS. + +But the volume of +AdS goes to infinity + +at-- near the +boundary, essentially, + +you always get infinity. + +So in order to get a +[? finite ?] answer, + +you need renormalization. + +So when you do renormalization, +essentially, you + +put the [? cut ?] off and +then you subtract covariant, + +the local counter terms. + +You put a cutoff. + +And then you subtract covariant +counter terms at the cutoff. + +And then you get +a finite answer. + +Then, you take the +cutoff to the boundary. + +So we will not go +through this procedure, + +but it's something you can do. + +But there's an +alternative shortcut + +to not go through these. + +Or you can just subtract-- just +calculate the Euclidean action + +for the cutoff, then subtract +the value of pure AdS. + +So if you calculate +the pure AdS, + +you will find the answer +is also divergent. + +You will find the answer +is also divergent. + +And you just subtract it. + +And then when you +do the subtract, + +you will find the +difference is [? finite. ?] + +And then you find the +difference is finite. + +And this is a slightly +simple way to do than that, + +but we also not do this +because, still, you + +have to calculate Euclidean +action [? and such. ?] + +So the synchron-- shortcut is +to assume thermal dynamics. + +That's what we did last time. + +Because you can find the +entropy density very easy. + +So entropy density-- +did I erase my-- + +so the entropy density +is just, essentially, + +the area of the horizon. + +So the entropy-- right now, it's +actually the total entropy, not + +the entropy density because +now we are [? almost here. ?] + +So the entropy would be-- +and size of the sphere + +will be r0 to the power d +minus 1 times omega d minus 1. + +Omega is the volume +of a unit sphere. + +And then divided by 4 pi 4GN. + +So this is the +entropy of the system. + +And you can express this +in terms of the temperature + +because r0 is a +function of temperature. + +r0 is a function of temperature. + +If you invert this, +you can imagine r0 + +is a function of temperature. + +So you have-- essentially +you have entropy + +as a function of temperature. + +And-- Hm? + +AUDIENCE: d minus +1, what's that? + +PROFESSOR: +[? Formula ?] d minus 1 + +is the volume of +the unit sphere. + +So you know the entropy. + +You can just use the formula +S equal to minus F minus T + +divided by T to-- +so you can also + +write this as minus F r0, +partial r0, partial T, + +et cetera. + +And then you can +integrate this equation + +to find the-- to find +F as a function of r0 + +because we know how the +r0 depends on T from here. + +So you just need to +integrate this equation. + +So this is a simple +exercise because now + +you just need to do an +integral of some function. + +And then you find omega +d minus 1 divided by 16 + +pi GN, r0 d minus 2 minus +r0 d divided by R squared. + +You get actually a +rather simple answer + +if you do that integration. + +So we have chosen the +integration constant so + +that when r0 equals +to 0, this is + +0 because r0 equal to +0, if the black hole has + +0 size, essentially, +[? there's ?] no black hole. + +And then we have +chosen the free energy + +to be 0 for the +[? no ?] black hole. + +So this free energy, +again, should + +be interpreted as the +difference with the pure AdS. + +So for the black hole-- this +is the black hole free energy + +because, by definition, +this way, the pure AdS, + +you just have 0. + +Any questions about this? + +So now you see here, +clearly, this expression. + +So now this is a +free energy now. + +This is not the +Euclidean action. + +So they differ by the +amount [? assigned ?] + +in my convention. + +So now you see that there +exists r0, critical r0. + +F black hole is greater than +0 Free energy is greater + +than 0 for r0 is smaller than R. + +So you can write it as formula d +minus 1-- so let me just write. + +Yeah, you can put the omega-- +the r0 to that [? out ?] + +for the overall factor r0. + +Yeah, put d minus 2 +out, and this just + +becomes 1 minus r0 squared. + +So you find that the free +energy is greater than 0. + +But r0 is greater than 1. + +That's greater +than the-- so this + +is greater than the +value of the thermal AdS. + +And the black hole +is smaller than 0. + +The free energy [? smaller ?] +than 0 become great than R. + +So the r0 is somewhere here. + +So r0 is somewhere here. + +It has to exist above +the-- it's somewhere here. + +This is r0. + +This is this r0 critical +[? as you go ?] to R. + +This is r0 critical +[? as you go ?] to R, + +somewhere here. + +So it's always a big black hole. + +And you can find out what is +this critical temperature. + +So the critical temperature is +just the beta evaluate at r0 + +equal to R. And then +you can find out + +that this is 2 pi R +divided by d minus 1. + +Just using this formula +you can find out it's that. + +So now I emphasize that +this is a phase transition. + +And this is not only +a phase transition, + +this is actually a first +order phase transition + +for the following reason. + +So in our unit, below +here, the free energy + +is 0 times order N squared. + +It's 0 times N squared. + +But about here-- well, +actually, above Tc-- at Tc, + +the free energy is +exactly equal to 0. + +So [? r0c ?] is +equal to R at Tc. + +There's a free energy. + +It's exactly 0. + +So at Tc, the-- a big black +hole and the thermal AdS + +have the same free energy. + +So they can exist together. + +And above here, then the free +energy of the big black hole + +is some negative number times +order-- times N squared. + +So your free energy +has a huge change. + +So essentially, the first +derivative of free energy, + +is discontinuous across +the phase transition. + +So this is actually a first +order phase transition. + +So this is-- yeah, let +me just emphasize that. + +So this is a first +order phase transition, + +with the free energy equal +to order N to the power 0 + +when T is smaller than Tc and +some nonzero number times N + +squared. + +Well, T greater than Tc. + +Any questions? + +AUDIENCE: When r0 is equal +to R, then F is equal to 0. + +PROFESSOR: Yeah. + +AUDIENCE: Then, why is the-- oh. + +PROFESSOR: No, the derivative +of F should be discontinuous. + +No, F is continuous. + +No, this is a definition of +the-- for the phase transition, + +the free energy is +always continuous. + +And then the free-- so the +first derivative here will + +be proportional to N squared. + +And you can check-- Yeah? + +AUDIENCE: So the point is-- OK, +so just see if I understand. + +So the point is that +it's discontinuous + +in the limit of +large N or something? + +I mean-- + +PROFESSOR: Yeah, that's right. + +That's right. + +Exactly. + +So let me emphasize. + +So this is N goes +to infinity limit. + +Is there any other questions? + +So we see there's a lot +of [? rich ?] story when + +you go to the sphere. + +And, actually, there's +a phase transition. + +And the phase transition +roughly [? adds to-- ?] + +the black hole size +is the AdS radius. + +Exactly the black hole +size is AdS radius. + +And this is, more or less, what +you expected because that's + +where the physics become +nontrivial because when + +the horizon is much, much +smaller than the black hole + +[? size-- ?] than the +curvature radius, as I said, + +just should reduce to the flat +space black hole and et cetera. + +Yeah, because the curvature +radius is only scale here. + +So now, let me make +another remark. + +Now, I erase this. + +I think it's OK. + +Yeah So you should +actually check yourself. + +So below Tc, the F +prime is always 0. + +When you take the +derivative, it's + +always 0 at order N squared. + +Let me, again, write this +answer, 0 times N squared. + +So you should check that +the first derivative of F + +is discontinuous. + +AUDIENCE: So F itself +is not discontinuous? + +PROFESSOR: No, F is not +because the F is 0 precisely + +at T equal to Tc. + +So F is equal to 0. + +And the-- Yeah. + +So the reason the first +derivative is discontinuous + +is very clear because +below Tc, this is 0. + +So the first derivative +is 0 times N squared. + +And above Tc, the +derivative is the derivative + +of the free energy of the +black hole at I equal to r0. + +And, clearly, the +derivative is nonzero. + +At I equal to r0, the +derivative is [? nonzero. ?] OK? + +And so you see, +they're discontinuous. + +So since physics only depends on +the [? dimensionless ?] number, + +R times T-- So large R, +small T-- large R at fixed T + +essentially is the same as +the, say, large T fixed R. + +It can only depend +on the ratio of them. + +OK? + +It depends on the +product of them. + +So you can either think +of-- you can either + +think you fix the +temperature, you + +increase the size of the sphere. + +Or you fix the +size of the sphere, + +you increase the temperature. + +[? In ?] fact, the same +is to increase this guy. + +And this is essentially the +limit going to the flat space. + +It's going to the R to the T. +If you take R go to infinity, + +you go to a [? theory ?] +on R d minus 1. + +So we see that the +theory on R d minus 1 + +is mapped to the high +temperature limits + +of the theory on the sphere. + +So essentially, just +corresponding to the 1 + +point for the +[? theory ?] on the sphere + +and this infinite temperature of +the [? theory ?] on the sphere. + +So that's why, as +we said before, + +because there's no scale here, +the [INAUDIBLE] temperature + +from here is essentially +the same in the flat space. + +And in particular, this is +described by a big black hole. + +And this is exactly +what we see before + +because when the black +hole become very big, + +then you can approximate +it to a plane + +because, locally, it's +like a plane [? anymore. ?] + +And the spherical horizon +is just like a plane. + +And then you go to +the black plane-- + +you go to the black hole +with the flat horizon. + +AUDIENCE: Why are the phases +only dependent on R times T? + +PROFESSOR: Yeah, because +this a CFT and this + +is only dimensions number. + +It can only depend on them +through this dimensions number. + +There is no other scale. + +Good? + +Other questions? + +Yes? + +AUDIENCE: So on the +side of the CFT, + +what are the different phases? + +I didn't- + +PROFESSOR: Sorry? + +AUDIENCE: What are the different +phases on the CFT side? + +PROFESSOR: Yeah, that's what +we are going to explain. + +So now, we have to describe +the black hole story. + +Or now, we have described +the gravity story. + +Just by looking at +the gravity size, + +we saw there are +three possible phases. + +At low temperature, you +get this thermal AdS phase. + +At high temperature, you +get big black hole phase, + +and then there is a phase +transition between them. + +And then, also, you have +unstable small black hole + +phase, which never +appears as a stable phase + +at any temperature. + +So, now, let's try to see +whether we can understand this + +from the Field Theory side. + +What does this mean from +the Field Theory side? + +Why somehow-- if I, for example, +put [INAUDIBLE] on a sphere, + +do I expect such kind +of phase transition? + +Does this make sense? + +Oh, by the way, +I should say this + +is the-- so this is called +a Hawking-Page transition. + +So this is called a +Hawking-Page transition. + +So remarkably, +this was discovered + +in 1980-- I think '81 +or '82, almost 20 years + +before this AdS/CFT conjecture. + +But they already +figured out that there + +is a phase transition. + +They were-- so they were +looking at the black holes + +[? and ?] AdS, and they said, +oh, there's two black holes. + +But there's also some AdS. + +And then, somehow, +there's some kind + +of phase transition +between them. + +But because they don't +know the Field Theory, + +they don't know this +should correspond + +into some kind of +Field Theory system. + +But they figured out this +gravity story essentially + +in 1981. + +Now, let's explain what +should be the Field Theory + +interpretation of +this-- The Field Theory + +explanation of this. + +Physical reasons for +Hawking-Page transition. + +So now, I will +consider a toy example. + +So I won't consider-- +so [INAUDIBLE] + +on the sphere, that's a +little bit too complicated. + +But I'm going to +consider toy example. + +And you will see, +from this toy example, + +that the physics behind this is +very simple and actually, also, + +[INAUDIBLE]. + +So let's consider you have N +squared harmonic oscillator-- + +free harmonic oscillator. + +So let's just +imagine you can take + +them to be different +frequencies-- [? let's ?] just + +even for simplicity-- or +for the same frequency. + +Say, omega-- I have some omega, +which I just take to be 1. + +Doesn't matter. + +So just consider N squared +free harmonic oscillator. + +So I claim when N-- when +N goes infinite limit, + +this system have the +same phase transition-- + +have exactly the same phase +transition described there. + +So, now, I will explain. + +So first, let's +look just at-- this + +is a system we know how +to solve exactly, so let's + +look at the spectrum. + +So this is total spectrum, the +total energy spectrum of this N + +squared harmonic oscillators. + +So let's call the +0, the ground state. + +So let me normalize the +energy so that the ground + +state have energy 0. + +And then you can excite +one harmonic oscillator, + +and then you have state of 1. + +Yeah. + +Actually-- Yeah, +have state of 1. + +And you can have two harmonic +, oscillator et cetera. + +And then you'll have many +harmonic oscillators, say, + +of all-- then, you're going +to have almost every harmonic + +oscillator excited. + +And then you have energy of +order N squared, et cetera. + +So now you have to imagine a +slightly nontrivial condition. + +Now, you have to imagine a +slightly nontrivial condition, + +which this is the +only thing [? reach ?] + +beyond the harmonic oscillator. + +Yeah. + +Actually, I just realized this. + +I slightly oversimplified +the story a little bit. + +Yeah. + +Yeah, let me say this way. + +Yeah. + +Let's consider 2N +harmonic oscillators. + +So let me arrange it +into two matrix, A and B. + +And they are all free. +it doesn't matter. + +For this purpose, it doesn't +matter how many harmonic-- just + +imagine I have arranged +them into two matrices, + +so I have two N squared +harmonic oscillators. + +And then I can excite them. + +But, now, I have a condition. + +So I have a condition, which +is analog to the condition + +of the gauge invariance. + +Instead, I want all +the states to be + +the trace singlet +created by A and B. + +You have A, B, et cetera. + +So A have N squared creation +and annihilation operator, + +and B have N squared +annihilation-- creation + +and annihilation operator. + +And then you can +act them-- then, + +you can [? accurately ?] +form the spectrum that it is. + +But there's a-- but also I +need to add a gauge invariance + +condition. + +It's that the state +[? acted ?] by A and B + +have to be SU(N) singlet. + +And SU(N) is the conjugate. + +Just imagine A and b +transformed under some SU(N) + +[? join representation. ?] +And they + +have to be the SU(N) singlet. + +So equivalent statement say that +the trace A and B-- the order + +state has to be +created by operators + +inside the trace, single trace +or multiple traces, et cetera. + +So is this clear? + +AUDIENCE: So one thing. + +So A and B are operators? + +Or they are-- + +PROFESSOR: They're operators, +harmonic oscillators. + +AUDIENCE: Oh, I see. + +PROFESSOR: Yeah. + +Imagine you have two +matrices under-- and two + +harmonic oscillators +that form two matrices. + +And each of them have N +squared harmonic oscillator. + +And if I just say they +are free, then you + +don't even have to think +about the matrix structure. + +AUDIENCE: So the only thing, +I'm confused about the matrices. + +So are the matrices acting on +some [INAUDIBLE] So in other + +words-- + +PROFESSOR: Yeah. + +Let me be a little +bit more explicit. + +[INAUDIBLE] Think about +the foreign system. + +The Lagrangian 1/2 Tr +A dot squared, Tr 1/2, + +Tr B dot squared minus 1/2 +Tr A square 1/2 Tr B squared. + +So this is a free +harmonic oscillator. + +So these are two N squared +free harmonic oscillators + +with frequency 1. + +So if I don't impose +this singlet condition, + +this is just a purely +free harmonic oscillator. + +But now, I [? require ?] +all the state-- + +and so SU(N) transformation-- +[? yeah, you can act them. ?] + +But now, I impose the +condition that they will have-- + +they should be SU(N) singlets. + +So they can [? create ?] +it by A and B, et cetera. + +But they should +be SU(N) singlet. + +Good? + +So now one thing +you can convince + +yourself is that because +of the trace condition-- + +so if you think about the +state of energy 1 or 2, + +et cetera-- so as far as the +energy is order N to the power + +0, so as far as the energy +does not scale with N, + +you can check yourself the +density of state-- the way + +you can-- the degeneracy +of those states + +will always be of +order N to the power 0. + +So this is a fact. + +You can convince yourself. + +And when you go to the +energy of order N squared, + +then you can check that +the density of state + +become exponential +of order N squared. + +So the reason for +this is very simple. + +So the reason for this is +very simple heuristically. + +So the reason for +this is very simple + +because if you have a state +of order 1, which does not + +scale with N, means there's +only order 1 states-- order + +1 oscillators are excited. + +And then, of course, +the density of state + +will be independent of N. And +if you do have energy of order + +N squared because each +of-- each oscillator + +has a frequency of 1, and then +you have energy N squared. + +And then that means order N +squared oscillator is excited. + +And then you have order Ns-- +if you have order N squared + +oscillator excited, then how +many ways you can choose them + +to construct the [? state of ?] +energy order N square and that + +[? exponential ?] +of order N squared. + +So imagine each +of the states, you + +can have N possible oscillator +to act, say, for each of them + +for twice. + +Then, you have 2 to +the order N squared + +probabilities of doing that. + +So that's where this +[? exponential ?] order + +N squared come out. + +So this is a fact. + +You should try to +convince yourself + +if it's not obvious to you now. + +So the reason I add this +singlet condition is for here. + +If I don't add a +singlet condition, + +then there's some +kind of independence + +here, which I don't want. + +There can be [? log ?] +independence. + +Yeah, just-- yeah. + +So this makes [? your ?] story +a little bit [? convenient. ?] + +Oh, so now-- yeah. + +We're running out of +time unfortunately. + +So now let's consider +the free energy, + +which, roughly, you can +consider as integrates + +of all possible states with +this weight factor and times + +the density of state. + +[INAUDIBLE] because +the free energy + +sum of all states, +minus BH, and the sum + +translated into the integral +with a density of states. + +And then that +translates into that. + +So naively-- so we +always consider-- + +so our beta is always-- does not +scale with N. That's order 1. + +It's always order 1. + +So if you look at here +naively, only state + +of energy of order +that's not scale N + +will contribute significantly +because of this suppression. + +Because of the thermal +suppression, say, + +if you have energy +of state of order + +N squared, then this +is a huge suppression. + +Then, they should +not contribute. + +Then, they should not make +a visible expression-- + +a contribution to +your free energy. + +Expect, except when those states +have a huge density of states. + +So except when those states +have a huge density of states. + +So, here, we see those +states have actually + +order N squared +density of states. + +So that means, in here, in that +integral, you have beta times + +order N squared-- something of +order N squared and then times + +something positive +of order N squared. + +When you can see the +contribution of the state + +of energy of order N squared. + +So when this factor +dominate over this factor, + +then the entropy will overwhelm +the thermal suppression. + +And then, such +state will dominate. + +And that precisely happens +when beta becomes small enough. + +Because when beta +becomes small enough, + +when you got the high +temperature, then + +beta decrease. + +So eventually, this +will overwhelm this one + +because the beta will decrease. + +And that's precisely the +Hawking-Page transition + +we'll see. + +So at low beta-- at big +beta or small temperature, + +thermal-- this one dominates. + +And then, the [? V ?] would +be of order N to the power 0 + +because only state of +order-- energy order zero + +will contribute. + +But the beta-- when beta +is sufficiently small, then + +the [? log ?] D(E) minus BE +can become greater than 0. + +And then the order N squared +states will dominate.| + +And then you find +the-- then, you find + +the [? partial function ?] will +be [? exponential ?] of order N + +squared. + +And that's precisely what we see +in the Hawking-Page transition. + +So I emphasize that +physics here have + +nothing to do with the +details of the system, + +only related to the large N +and to the density of states. + +So if you have interactions, +if you have more complicated + +system, it doesn't matter. + +It doesn't matter. + +As far as your [INAUDIBLE], +this phenomenon will happen. + +This phenomenon will happen. + +And so this is the essence of +the Hawking-Page transition. + +We will stop here. \ No newline at end of file diff --git a/rxiAQe0t-ZU.txt b/rxiAQe0t-ZU.txt new file mode 100644 index 0000000000000000000000000000000000000000..a888b08b70b3a335650da6cbf018f3fe348d7d4d --- /dev/null +++ b/rxiAQe0t-ZU.txt @@ -0,0 +1,1145 @@ +Good morning. Thank you. So, I want to continue today on the + +theme of neurobiology. Last time we spoke about the action + +potential mechanism. Today I'd like to go from action + +potential to the synapse. But let me briefly remind us what we + +say. So, I'm going to give section zero a recap here. + +The relevant things that we said last time was there's a membrane + +potential which at rest is about minus 70 millivolts as the membrane + +potential, and that's what we work with. That membrane potential is + +set up by concentration gradients. More calcium, more potassium on the + +inside. More sodium on the outside. More calcium on the outside. And + +I'm also going to mention chloride, there's more chloride on the outside + +at 116 millimolar, four millimolar on the outside. + +These concentration gradients are set up by various different pumps. + +They're there all the time. Then we have this resting channel. + +So, here we have transporters. + +We have a resting potassium channel. It means that it's open all the + +time. It's not activated by anything. + +That allows potassium to leave. Potassium leaves until it builds up + +this membrane potential about minus 70. At that point it is + +electrically unfavorable for more positive charges to go out into the + +more positive environment. Notwithstanding the greater + +internal concentration. And we reach an equilibrium + +potential of minus 70. We then have some voltage-gated + +channels. + +And the voltage-gated channels come in two flavors here. + +We have the voltage-gated sodium channel. The voltage-gated sodium + +channel opens itself up around minus 70. Oh, sorry, + +around minus 50. So, if you can get up to minus 50 + +it opens up. Then your sodium rushes in. It shifts the membrane + +potential from minus 50 to zero to plus 50. + +The channel shuts. Somewhere around plus 30 or so + +opens the potassium channel, the voltage graded potassium channel, + +and allows the potassium to rush out and restore the resting potential. + +The effect of this is that, if this is zero here, we have + +a resting potential. If we climb up a little bit above it + +we shoot up and then we come back down. And then a millisecond or so + +later another action potential could go down that same neuron. + +And, last of all, if we look along the length of an axon, + +an action potential here causes charges to migrate over which + +launches an action potential here which causes charges to migrate over + +which etc., etc. propagates an action potential down + +the length. It's a beautiful system. + +And then the very last thing was that by insulating this we were able + +to make the conduction velocity go faster by effectively making the + +effective length be shorter there being a whole bunch of electrically + +insulated regions. So, that's it. It's a beautiful + +piece of engineering. How do we know any of this is true? + + As an interesting side point, + +I might just mention that when this was worked out, + +this was worked out by two folks called Hodgkin and Huxley. + +Hodgkin and Huxley won a Nobel prize for this beautiful work on + +this squid giant axon which is the fastest axon that there is. + +And here we're not talking about the giant squid somebody raised last + +time. It's an ordinary squid. It has one big fat axon. It's + +sufficiently big that you can just like stick a wire in the middle of + +it and all that. It's a very big axon. + +It's a very, very high diameter axon. + +And they were able to measure these things electrically. + +And on the basis of the electrical measurements they made in different + +kinds of solutions, they were able to infer the + +existence of sodium channels and potassium channels. + +But this all happened mid 20th century. And they certainly + +couldn't see any. They couldn't clone them. + +They couldn't see anything. And so the notion that there were + +individual molecular channels that swung open, did all this stuff was + +an indirect inference, maybe kind of a little bit like + +Mendel's inference of a gene or Sturtevant's inference + +of genetic maps. But more recently people have come + +along with an extraordinary technology, also these people won a + +Nobel prize for this because it was way cool, which is called the Patch + +Clamp. The patch clamp is the following ridiculously simple + +technology. Suppose I were to make a glass pipette. + +So, this is a cross-section of a glass pipette. + +So, it goes around like that. And I could bring it up really + +tight up against the membrane. And suppose I did it in such a way + +that I could get a really great seal and I just have a teeny patch of + +membrane. Suppose that teeny patch of membrane had just + +one channel in it. And now, so this is a pipette, + +suppose I were to rip off that patch of membrane from the cell, + +poor cell, and have a glass pipette with a little patch of membrane on + +its end with a single isolated ion channel. Now, + +if I measured the current through this channel by putting it in an + +appropriate solution, maybe I ripped off a resting + +potassium channel, OK? If I put this in a potassium + +solution and I apply a current, I apply a voltage difference, I + +should be able to see a current. And you can actually measure a + +current. Even more cool, if I do this and I've ripped off a + +voltage-gated sodium channel, then it turns out that I ought to be + +able to study its properties by changing the voltage on it and + +measuring the current as a function of the voltage. + +And, well, it turns out that if I do this I'm able to measure in resting + +or in these voltage-gated channels current flows conductivities, + +actually, what I'm really measuring is the conductivity of the channel + +like this, I can see the channel opening and closing and opening and + +closing quantily. I can measure quantily the + +conductivity. That's not quantum mechanics. It's just quanta + +measurements of the conductivity. What would happen if I had two + +channels that had been ripped off? Now I'd see it go like this. + +Well, maybe another one opens. Oops, now one closes. Now the + +other one closes. And quite remarkably you can get + +this. So, you can study single molecule, single molecular channels. + +You want to know how this channel opens and at what voltage it opens? + +Just dial in the voltage and see if it's open. Do you want to know how + +long it stays open? Just turn it on and see how long it + +stays open. It's really cool. You want to see if any other + +chemicals could affect it, any ions, any other intracellular or + +extra cellular chemicals? You can do it. + +So, the ability to study isolated single channels came along with + +patch clamping. And what it allows is a tremendous + +study of the biophysics of individual channels. + +And, whereas, before people had to look at the total conductivity of an + +entire axon. Now they're able, and from that infer the behavior of + +single channels, now what they can do is study the + +behavior of single channels and synthetically build up a picture of + +the total conductivity of an axon from its individual components and + +see if the components we've identified are sufficient to explain + +the behavior that we see. Anyway, that's patch clamping. + +Lots of fun. So, now, what I want to turn now to is signaling + +at the synapse. + +So, we have our cell body here. It's got its dendrites on it. + +Here's our axon. We've managed to get an action + +potential started on it and it moves all the way down. + +Now we get here to one of the synaptic terminals. + +The electrical signal makes it all the way to the synaptic terminal, + +but how does it affect the post-synaptic cell? + + Well, let's get a close-up of that. + +Here we go. Here's the synaptic terminal. We've got our action + +potential coming. Action potential coming. + +And then it gets here. Action potential's arrived. + +I would like to release chemicals into the synaptic cleft, + +the space between the pre and the post-synaptic cell. + +I'd like to spill out chemicals that are neurotransmitters. + +So, the pre-synaptic cell conveniently has vesicles, + +little membrane-bound vesicles with prepackaged neurotransmitters. + +OK? These prepackaged neurotransmitters have been + +conveniently synthesized by the cell and they're just sitting there + +waiting to be released in response to an action potential. + +When the action potential comes, it causes these synaptic vesicles to + +fuse -- + +-- with the membrane. And in fusing the insides become + +continuous with the outsides, here's a little fusion picture here, + +and the neurotransmitters leak out. OK? + +How does it do that, though, mechanistically? + +How in the world does an action potential cause these vesicles to + +fuse with the membrane? Well, somehow it's got to read out + +electrical activity into some kind of a chemical activity + +intracellularly. Here's what it does. + +When the electrical signal comes down, remember originally the + +membrane potential is negative, but when an action potential comes + +by what does it do to the membrane potential? It reverses it. + +It makes it positive inside briefly. OK? So, this is the sign of an + +action potential, an AP coming down. + +In this membrane we have us another voltage-sensitive channel. + +This voltage sensitive channel is a voltage sensitive calcium channel. + +OK? Who would like to design a voltage-sensitive calcium channel? + +What should it do? What would you like to have its opening and closing + +properties be? When does it open? + +At a positive charge. So, when you get to a positive + +membrane potential it swings open. And then what does it do? + +Lets calcium move. Which way does calcium want to go? + +In because it's more out. So, what's going to happen is in + +response to the action potential calcium will rush in. + +Now, calcium, you will recall, was in vanishingly small traces + +inside, 0.1 micromolar we said. And influx of calcium is a very + +serious matter and it is sensed by variety of proteins. + +In particular, there is, floating around in the + +cell, a protein here called a calcium-dependent protein kinase. + + The calcium-dependent protein kinase + +is a protein that is capable of putting a phosphate group. + +Its kinase puts a phosphate group on other proteins. + +So, the calcium-dependent protein kinase over here will go along and + +catalyze the addition of a phosphate group to other proteins. + +So, it will enzymaticly catalyze this. But it only does so in the + +presence of calcium. So, when there's calcium in the + +cell, the calcium-dependent kinase is activated and it runs around and + +sticks phosphate groups on specific target proteins. + +You know where one of those target proteins lives? In the vesicles. + +The vesicles happen to be a target for this. So, + +the vesicles have a protein on them. And in one of these extraordinary + +coincidences in molecular biology, the protein on the synaptic vesicle + +happens to be called, coincidently, synapsin. + +OK? It's not actually entirely a coincidence that it's called + +synapsin. It was named synapsin because it was found on the synaptic + +vesicles, obviously. And so what happens is when the + +action potential comes down it causes the calcium channel to open + +in response to positive voltage. Calcium comes in, + +actives at the kinase. The kinase phosphorilates synapsin. + +And now the phosphorilated form of synapsin likes to bind to something + +in the membrane. That's it. How many of you still + +know what a Rube Goldberg machine is? Good. OK. This is one of these + +just great, well, others of you should look it up on + +the Web because they're just great cartoons, the Rube Goldberg cartoons + +about the machine where the rooster crows startling the cat which tugs + +the thing with causes this to flop which causes the eggs to go in the + +pan which causes the thing to cook which causes whatever. + +And I always think about these in terms of great molecular Rube + +Goldberg machines. So, this is the Rube Goldberg + +machine that gets this synaptic vesicle to fuse there. + +OK? Good. Every bit of neurobiology has a molecular + +mechanism to be explained like this. So, now let's go onto the next + +bit. How does this signal gets sensed at + +the next cell? What are we up to? + +Number three. So, let's look at a specific junction. + +Instead of looking at the junction between two nerve cells, + +let me start with the junction between a nerve cell and a muscle + +cell, the neuromuscular junction. OK? So, I've now replaced my + +post-synaptic neuron by a muscle fiber here. This is + +a muscle fiber. So, when it spritzes out the stuff + +the neurons that innervate muscle fibers, actually, + +I'm going to expand that a bit, the neurons that innervate muscle + +fibers, here's the muscle, and I'll put it at some distance + +here, muscle, spray out a particular transmitter in response + +to the calcium influx. And that transmitter is called + +acetylcholine, henceforth ACH. + +Acetylcholine is spritzed out into the synaptic cleft and comes out. + +And what do you think acetylcholine is going to do? + +I've got to send the chemical signal to the next cell. + +I've got to somehow send that signal to the surface. + +It's going to bind to something on the next cell. + +You know the deal, right? So, it's going to have to + +bind to a protein on this cell. And, remarkably, what it binds to + +is called an acetylcholine receptor. OK? Very reasonable stuff. An + +acetylcholine receptor. The acetylcholine receptor happens + +to be an ion channel, but it's not a voltage-gated ion + +channel. It's not an ion channel that opens in response to the + +voltage. It's an ion channel that opens in response to acetylcholine. + +It's what we'd call a ligand-gated ion channel because it's gated by a + +ligand, acetylcholine. So, this guy here is a ligand-gated + +ion channel which, when acetylcholine binds to it, + +swings open. And what it does is it allows in sodium. + +Bingo. Now, when sodium comes in what happens? Action potential. + +But what a second. This is a muscle. + + All membranes have the machinery to + +have an action potential? Nah, liver cells are pretty passive. + +You do this to a liver cell it kind of sits there. + +But muscle cells do have an action potential mechanism. + +They do respond here like a neuron, an action potential. And so what + +happens when I open up some sodium channels to the resting potential + +of my muscle? What was the resting potential of my + +muscle? About minus 70. What happens when I open up these + +ligand-gated sodium channels? Sodium rushes in. What does it do + +to my membrane potential? It makes it more positive. + +What does that do? It triggers an action potential spreading + +throughout the muscle. And because the muscle has an + +action potential -- + +-- all you have to do is manage to get this going in a little patch of + +the muscle and it spreads throughout the muscle fiber. + +One neuromuscular synapse will be sufficient to activate the muscle, + +in principle, because you have this action potential mechanism. + +And then when the action potential fires in the muscle it actually + +causes other channels to open, including some calcium channels. + +The calcium channels cause calcium to come in. The calcium causes your + +muscle to contract because of sliding of actins and myosins and + +things like that. That's how it works. + +That's this Rube Goldberg machine. All right. So, let's get ready. + +Let's fire. Let's send a neuromuscular signal down. + +Contract. Now here's the problem. I've got all this acetylcholine + +sitting around in my synapse activating the ligand-gated sodium + +channel causing sodium to come in, but I would like to relax my muscle, + +please. What are we going to do about this? + + I could trigger another channel, + +and maybe it could be a delayed acetylcholine activated yeah, + +dah, dah, dah, dah, dah, dah, that's possible. I could have it close + +itself. These are all perfectly reasonable possibilities, + +and we're going to refer them to the engineering committee. + +What else? You could get rid of the acetylcholine some other way. + +It turns out the latter is the solution here. + +We would like to have some enzyme that chews up the acetylcholine. + +How about acetylcholinesterase? So, let's put acetylcholinesterase, + +ACHE, acetylcholinesterase in the synaptic cleft. + +Then when I spritz acetylcholine it gets to the other side, + +but very rapidly the acetylcholinesterase is degrading it. + +And so it has a very short time of persistence in the synaptic + +cleft. OK? That works. So, + +that's how I run a neuromuscular junction. OK? + +So, acetylcholinesterase is very important. Now, + +again, as with many of the things I've talked about, + +we really know these things are true when we're able to inhibit them in + +different ways. So, I want to take a moment and + +talk about drugs and toxins. Because they help us to probe these + +different processes. Anybody ever have fugu? + +Does anybody know what fugu is? What's fugu? It's a blowfish. + +Right. It's a puffer fish eaten in sushi, and it's an extraordinary + +delicacy. And why is that? Right. Because it's one of the only + +sushis where you really have to worry about improper preparation, + +not just giving you food poisoning or a stomachache or something like + +that, but it's lethal prepared incorrectly. The reason it's lethal + +incorrectly prepared is because the blowfish has a specific poison + +called tetrodotoxin. So, if you eat sushi, + +so, in fact, chefs in Japan require a license to prepare fugu + +for customers. Every once, every couple of years + +some famous actor or personality prepares his or her own fugu and + +dies from it and it's in the papers. Seriously. This has happened to + +people. They're able to do this. Anyway, tetrodotoxin, tetrodotoxin + +is from puffer fish, fugu. Why does this stuff kill you? + +It turns out that what tetrodotoxin does, this wonderful poison from + +this sushi, is that it irreversibly binds, irreversible binding and + +inhibition of voltage-gated sodium channels. + +Why would this be an inadvisable thing to have? + +Suppose you irreversibly bound to and inhibited your sodium channels, + +your voltage-gated sodium channels, what would you be unable + +to accomplish? An action potential. + +This is ill-advised to be unable to accomplish an action potential. + +You can imagine that what it leads to then is a paralysis and a very + +serious one, and if it's irreversible this is not a good + +thing. There are other things. Has anyone ever fired poison darts + +in South American jungles? [LAUGHTER] + +Well, if you have, you would have tipped them with + +qurare. Qurare is used to make poison darts. What qurare does is + +it reversibly binds, still not good, but it's a + +reversible binder to the acetylcholine receptor and it + +prevents it, it blocks the binding of acetylcholine. + +Your acetylcholine receptors, therefore, cannot respond to your + +acetylcholine. What will that do? + +A flaccid paralysis because you're unable to move your muscles. + +So, if you were trying to shoot prey in the forest and you send the + +poison dart that has qurare, it will cause the animal to then + +flop over. Yes? Snakes. Ooh, + +what kind of snakes? Venomous steak snakes, + +yeah. [LAUGHTER] Like bungarus snakes, the really poisonous ones. + +So, it turns out, great question, that they make something called + +alpha-bungerotoxin. Venomous snakes, + +next thing on my list, exactly. The only improvement they + +make here is that this is an irreversible binder to the + +acetylcholine receptors. Very impressive stuff. Different + +stuff. We'll come back to jellyfish. But, basically, + +everything you know out there that's noxious is being noxious in some way + +that affects molecular biology. Not all of it affects the nervous + +system. Those of you who like to collect mushrooms may wish to avoid + +amanitas mushrooms. They make amanitas. + +Amanitan is an irreversible binder that affects polymerase, + +RNA polymerase. Not a good thing to lose either. So, + +all parts of this course have interesting poisons that will affect + +it but we'll focus on the poisons effecting neurobiology today. + +And then there's a human made thing. Do you remember the, well, those of + +who have heard of World War I, nerve gas or, in particular, who + +remember the attack in the Tokyo subways with sarin, + +a particular kind of nerve gas. Do you know what that stuff does? + +It is a potent inhibitor of the enzyme acetylcholinesterase. + +What would happen if I inhibited your acetylcholinesterase? + +The muscles tense up and I'm unable to relieve them because, + +just like I was doing there, because my acetylcholine is not + +broken down in the synapse. So, this is a nice menu of + +interesting poisons and fun facts to know and tell and good things to + +avoid. There are more drugs and things that we can come back to. + +So, now let's talk about, let's move onto other synapses. + +Let's take a look at nerve-nerve synapses. + + So, we looked at a nerve muscle + +synapse. What were the properties of this nerve muscle synapse? + +Well, it had the property that a single neuron innervates a single + +muscle fiber. All right? This was a one-to-one single fiber, + +sorry, single neuron, single fiber. + +When we get to nerve-nerve synapses, they're more complex. Multiple + +different nerve terminals may synapse upon the same neuron, + +as I indicated last time. There might be a thousand different + +nerve terminals synapsing on the dendrites of a postsynaptic cell, + +but let's look at one of them for a moment. Then we'll come back to how + +a thousand can work together. So, here's one. + +And here's my dendrite that I'm synapsing on here. + +The nerve terminal releases into, sorry, into the synaptic cleft some + +neurotransmitter. It turns out there's a wide variety + +of neurotransmitters that get released while the neuromuscular + +junction involves acetylcholine. One example that might be involved + +here is something called glutamate. What's glutamate? + +It's an amino acid. Glutamic acid. It's the ion of + +glutamic acid. That actually is a neurotransmitter. + +Ever have monosodium glutamate. Does anybody get a headache from + +monosodium glutamate? I do. That's because it's a + +neurotransmitter. It messes with brain chemistry. + +So, glutamate. Glutamate is released. + +And what is does is there is a channel on the post-synaptic cell + +that binds glutamate. And it, too, is a ligand-gated ion + +channel. And it could be, for example, a sodium channel. + +Other neurotransmitters might use other channels. + +What happens if I spritz some glutamate on a dendrite of a cell + +that has a glutamate-activated sodium channel? + +What will happen in that dendrite? Sodium will rush in causing the + +membrane potential to become depolarized and then positive and + +then causing an action potential? No. It turns out that that last + +bit doesn't happen because the dendrites don't have the action + +potential machine. The action potential machinery is + +interestingly confined to the axon. It's not found on the dendrites. + +So, when we spritz with glutamate, what will happen is if this is a + +glutamate-bearing synaptic terminal the membrane potential here will + +become locally positive. But it is not an explosive + +regenerative action potential because there are no voltage-gated + +sodium channels that are going to open in response to that local + +depolarization. So, it became a little positive + +over in this corner of the neuron. Now, if it gets a little positive + +over in this corner of the neuron, you know, it's going to draw some + +negative charges from over here, right, to offset that local + +positivity. But if it's just a local little patch of positive then + +it draws a little bit of negative charge. But is that going to be + +enough to depolarize over here? No. So what do you want to do? + +Have more. Suppose I have two glutaminergic + +synapses and they fire, it might be. Probably not. + +Maybe they have to fire at the same time. Maybe if I have a hundred out + +of a thousand. Imagine that I have a hundred + +different glutaminergic synapses that fired simultaneously then what + +will happen? I'll get positive charges at all of them. + +And maybe that's enough to draw some negative charge away from the axon + +and start an action potential going, or maybe not. Maybe you need two + +hundred. What if they don't fire at exactly the same moment? + +Well, the minute one fires it makes it locally positive, + +but then it starts restoring itself so that if they're separated in time + +they're not as effective as if they happen simultaneously. + +So, we have an extraordinary complex analog integration + +circuit here. The analogy integration circuit + +depends on the temporal arrival of these signals. + +And what else does it depend on? The number of the signals. So, + +let's get this down. We're going to integrate the + +signals here. + +It'll depend on their timing, the number, and the geometry, + +because it turns out that doing it at different places in the, + +now, I drew my dendritic tree, the dendrites as all these little + +hairy spikes coming off the cell body, but the dendrites are vastly + +more complex than that. Some cells have elaborate dendritic + +trees. The dendritic tree, + +the dendrites of some neurons, here's the cell body, can go off in + +all sorts of wonderfully complex patterns. And it may be more + +effective to hit synapses close to the cell body or synapses on + +different parts of the tree. And so that the entire shape of + +that dendritic tree can have an effect, and where you're hitting it + +has an effect. So, whereas the action potential is + +a very simple thing, which you might say just replace it + +by a wire for our computer modeling studies, goodness, + +nobody has actually succeeded in building a perfect model of the + +integration properties of an dendritic arbor for a single neuron. + +They can get guess and approximations. + +So, there's an amazing integration that's going on here. + +But it turns out that it's more complex than that because, + +you see, I said that we had these, say, glutamate neurotransmitters + +here that were causing positive charges to rush in. + +It turns out there are other neurotransmitters that activate + +other channels in the membrane. And, for example, there are some + +neurotransmitters that activate, like glycine, another amino acid + +activates ligand-gated chloride channels. + +So, glutamate, one amino acid activates sodium + +channels. Sodium rushes in. Glycine activates chloride channels. + +What will chloride do? It can come in. + +What will it do when it comes in? Negative. Oh, my goodness. So, + +when glycine is spritz on the post-synaptic cell chloride comes in + +and the cell becomes locally more negative. These are called + +inhibitory synapses. + +By contrast those that admit positive ions excitatory synapses. + + Neurons can have both inhibitory and + +excitatory synapses on their dendrites. So, + +the postsynaptic cell will be receiving positive signals, + +positive ions coming in from excitatory synapse and negative + +signals, inhibitory signals with negative ions coming in. + +The integration of charge in the dendritic arbor is an integration + +problem of the timing, number, geometry and sign, + +positive or negative, of these activation signals. + +That's what's going on. And what happens is the neuron + +integrates these signals, positive and negative. So, + +we'll make this one a glycine neuron, negative, negative, negative. + +All that integration takes place right over here in the region of the + +cell called the axon hillock, which is the first place that the + +action potential mechanism is found. And, of course, that integration is + +nothing more and nothing less than figuring out whether the membrane + +potential gets above minus 50. If it gets above minus 50 it fires. + +OK? Yes? + +Does the nucleus participate in the, in what way would the nucleus + +participate? + +It's an interesting question. I mean the nucleus does, in a sense. + +The geometry of that cell body there has some effect on the + +electrical properties and all that, but if you think about the + +timescales. How often do neurons fire? At a frequency often of about + +a millisecond. So, that means everything I've just + +old you, this complex integration problem is occurring within + +a millisecond. The processes in the nucleus that I + +think about typically of transcription and translation and + +all that are operating several orders of magnitude more slowly than + +that. You know, they'll operate, even in the best of + +circumstances, at seconds, and often at more than + +that, minutes before you could get transcription and translation and + +stuff like that going. So, the nucleus, I think, + +for the most part, better get its act together by producing stuff and + +getting it out to the periphery, but probably through the expression + +of the genome can't do much in a relevant millisecond or so. + +But I wouldn't be shocked if some neurobiologist knows better than I + +do that nucleoli do something. I mean there are many cleaver + +things that are going on. I'm sure a cell has wasted anything, + +but with respect to the operations we've talked about probably not. + +OK? But I'm always reluctant to say something never happens in any + +possible way. All right. So, now how does all this get stuck + +together? Well, not only do we have this + +complex integration within the dendritic arbor but, + +of course, the neurons are stuck together into circuits themselves. + +If we had more time I would draw the circuit that you use to + +integrate complex functions in calculus, but not having much time + +I'm going to just go for a much simpler circuit here. + +I'm just going to go back to nerves and muscles. And here we go. + +Suppose I tap right here below your knee. What happens? + +There's a reflex. Let's at least get that going, + +OK? What happens is when I tap there above your patella, + +here's your kneecap here, there's a sensory neuron. + +The sensory neuron brings out a signal and it goes into the + +spinal column here. This is a reflex. + +It doesn't need to go up to your brain. You don't need to think a lot + +about it. And it goes into the spinal column here into the dorsal + +root ganglia. This is a cross-section. + +The, sorry, sensory neuron comes in here. And what it does is that + +sensory neuron makes a synapse, and actually another synapse, and it + +makes a synapse on a motor neuron. The motor neuron comes back and + +synapses on that very muscle. It is the simplest possible circuit. + +I sense, I send one sensory signal up into the spinal cord, + +there's an excitatory positive synapse onto a motor neuron, + +this motor neuron fires and contracts my muscle so I go back. + +At the same time, this guy makes another synapse, + +a positive excitatory synapse on a little cell that is an interneuron, + +that's an intermediate neuron. That intermediate neuron makes a synapse + +on a second motor neuron, but this is an inhibitory synapse. + + That motor neuron sends its process + +out and is affecting the opposite muscle. So now what happens? + +Let's get this straight. I hit over here. + +And the signal goes back to my spinal cord. The sensory neuron + +causes one motor neuron, directly by firing on it, + +to contract. It causes an interneuron to fire that inhibits + +the opposite motor neuron. What happens if you inhibit the + +opposite motor neuron? You relax the contraction, + +or you at least don't contract the opposite muscle. + +So, what happens is you send a positive signal to the muscle on one + +side and you inhibit the signal to the muscle on the other side. + +It's a very simple circuit. It's got one sensory neuron. + +Two motor neurons. One interneuron. It's got two positive excitatory + +synapses. It's got one negative inhibitory synapse. + +That's about it. Presumably, everything else that goes on in + +daily life is basically the same thing. This is probably what eating + +lunch is like, falling in love is like and things + +like that, although the details remain to be worked out for exactly + +how that stuff works. There is a large collection of, + +I give you the simple examples because obviously we don't know a + +lot of the complex examples. There is a lot more to this. + +If had time in the course we could go into what's known about more + +circuits. I joke. We know about the circuits that + +help you see vision, that allow you to pick up signals in + +your retina, transmit them back and reconstruct things with positive and + +negative signals that allow you to see a straight line, + +for example, and recognize a straight line. + +And there are patterns of cells that send positive signals and negative + +signals, and when you integrate them you can get a signal if and only if + +there's a straight line at this angle in your visual field. + +And people know about that kind of stuff, but some of the more complex + +stuff we don't know about. There are lots and lots of + +neurotransmitters, glutamate, glycine, + +histamine, serotonin. ATP can be a neurotransmitter. + +Adenosine can be a neurotransmitter. There are peptide neurotransmitters. + +Endorphins, oxytocins and even gases. Nitrous oxide is a neurotransmitter. + +And then some of the drugs you may know work by affecting these + +neurotransmitters. Prozac and the general class of + +selective serotonin reuptake inhibitors. Prozac effects a + +specific process with a neurotransmitter. + +There's a neurotransmitter serotonin. After it's fired out, + +instead of acetylcholesterase being in the synapse destroying it or some + +other enzyme destroying it, it's taken back up by the cells. + +If you could inhibit the process by which you take up your serotonin + +again, the serotonin would last longer in your synapse and you would + +be happier, give or take, roughly speaking to the extent that + +more serotonin is a good thing. And that's what Prozac does. + +Actually, it's one of the things Prozac does. There's good evidence + +now that Prozac does other things, too, including causing neuronal cell + +growth, but that's a whole other story. + +There are things like cocaine. Cocaine is a bad thing because it + +inhibits certain sodium transporters and other things. + +And if you go through all of the different psychoactive drugs they're + +affecting different parts of these processes. So, + +for Friday I've invited a colleague who is a real neurobiologist, + +I'm not a card-carrying neurobiologist, + +to talk about some of the more far out things of learning and memory. + +Andy Chess who's a good friend and a colleague is going to talk about + +learning and memory. And then have a good time with him, + +and I'll see you subsequently. \ No newline at end of file diff --git a/sKYY6o71iNM.txt b/sKYY6o71iNM.txt new file mode 100644 index 0000000000000000000000000000000000000000..eb9239b2ad0b58e4fce9228e92b037d25d282a2c --- /dev/null +++ b/sKYY6o71iNM.txt @@ -0,0 +1,595 @@ +align:start position:0% + +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +In this week's discussion of video, + + align:start position:0% +In this week's discussion of video, + + + align:start position:0% +In this week's discussion of video, +we're going to show you some interesting + + align:start position:0% +we're going to show you some interesting + + + align:start position:0% +we're going to show you some interesting +examples of other people's work. Now, + + align:start position:0% +examples of other people's work. Now, + + + align:start position:0% +examples of other people's work. Now, +remember that the basics of still + + align:start position:0% +remember that the basics of still + + + align:start position:0% +remember that the basics of still +photography that you've just learned all + + align:start position:0% +photography that you've just learned all + + + align:start position:0% +photography that you've just learned all +these previous weeks apply to making + + align:start position:0% +these previous weeks apply to making + + + align:start position:0% +these previous weeks apply to making +successful videos. For starters, we are + + align:start position:0% +successful videos. For starters, we are + + + align:start position:0% +successful videos. For starters, we are +incredibly lucky to be able to show you + + align:start position:0% +incredibly lucky to be able to show you + + + align:start position:0% +incredibly lucky to be able to show you +some remarkable videos from a project + + align:start position:0% +some remarkable videos from a project + + + align:start position:0% +some remarkable videos from a project +called Beautiful + + align:start position:0% +called Beautiful + + + align:start position:0% +called Beautiful +Chemistry. Here's the website with full + + align:start position:0% +Chemistry. Here's the website with full + + + align:start position:0% +Chemistry. Here's the website with full +credit. Now, I encourage you to see them + + align:start position:0% +credit. Now, I encourage you to see them + + + align:start position:0% +credit. Now, I encourage you to see them +all. I am quite sure they will inspire + + align:start position:0% +all. I am quite sure they will inspire + + + align:start position:0% +all. I am quite sure they will inspire +you to come up with your own amazing + + align:start position:0% +you to come up with your own amazing + + + align:start position:0% +you to come up with your own amazing +videos if your work requires video + + align:start position:0% +videos if your work requires video + + + align:start position:0% +videos if your work requires video +capturing macrolevel phenomena. + + align:start position:0% +capturing macrolevel phenomena. + + + align:start position:0% +capturing macrolevel phenomena. +Scientist Yan Leang, a collaborator of + + align:start position:0% +Scientist Yan Leang, a collaborator of + + + align:start position:0% +Scientist Yan Leang, a collaborator of +mine, is the creator and director of the + + align:start position:0% +mine, is the creator and director of the + + + align:start position:0% +mine, is the creator and director of the +project. We asked him to tell us a + + align:start position:0% +project. We asked him to tell us a + + + align:start position:0% +project. We asked him to tell us a +little about his techniques for three of + + align:start position:0% +little about his techniques for three of + + + align:start position:0% +little about his techniques for three of +the videos. Welcome Leang to our class. + + align:start position:0% +the videos. Welcome Leang to our class. + + + align:start position:0% +the videos. Welcome Leang to our class. +Thank you. It's wonderful being part of + + align:start position:0% +Thank you. It's wonderful being part of + + + align:start position:0% +Thank you. It's wonderful being part of +this course. I'll be happy to talk about + + align:start position:0% +this course. I'll be happy to talk about + + + align:start position:0% +this course. I'll be happy to talk about +how we capture three particular + + align:start position:0% +how we capture three particular + + + align:start position:0% +how we capture three particular +phenomena. In this segment, we are + + align:start position:0% +phenomena. In this segment, we are + + + align:start position:0% +phenomena. In this segment, we are +showing metal displacement reactions. We + + align:start position:0% +showing metal displacement reactions. We + + + align:start position:0% +showing metal displacement reactions. We +dropped zinc metal into different + + align:start position:0% +dropped zinc metal into different + + + align:start position:0% +dropped zinc metal into different +solutions and recorded the emergence of + + align:start position:0% +solutions and recorded the emergence of + + + align:start position:0% +solutions and recorded the emergence of +beautiful structures of other metals + + align:start position:0% +beautiful structures of other metals + + + align:start position:0% +beautiful structures of other metals +such as silver and + + align:start position:0% +such as silver and + + + align:start position:0% +such as silver and +lead. All the reactions were shot in + + align:start position:0% +lead. All the reactions were shot in + + + align:start position:0% +lead. All the reactions were shot in +real time and we sped them up during + + align:start position:0% +real time and we sped them up during + + + align:start position:0% +real time and we sped them up during +editing in Final Cut Pro X. For example, + + align:start position:0% +editing in Final Cut Pro X. For example, + + + align:start position:0% +editing in Final Cut Pro X. For example, +one shot of silver displacement was sped + + align:start position:0% +one shot of silver displacement was sped + + + align:start position:0% +one shot of silver displacement was sped +up 60 times, which means 1 second of our + + align:start position:0% +up 60 times, which means 1 second of our + + + align:start position:0% +up 60 times, which means 1 second of our +video is 1 minute in real time. For + + align:start position:0% +video is 1 minute in real time. For + + + align:start position:0% +video is 1 minute in real time. For +light setup, we use two large LED panels + + align:start position:0% +light setup, we use two large LED panels + + + align:start position:0% +light setup, we use two large LED panels +to light a cubic glass container in + + align:start position:0% +to light a cubic glass container in + + + align:start position:0% +to light a cubic glass container in +which the reactions occurred. Typically, + + align:start position:0% +which the reactions occurred. Typically, + + + align:start position:0% +which the reactions occurred. Typically, +a black clothes or a white plastic board + + align:start position:0% +a black clothes or a white plastic board + + + align:start position:0% +a black clothes or a white plastic board +was placed about 1 ft behind the + + align:start position:0% +was placed about 1 ft behind the + + + align:start position:0% +was placed about 1 ft behind the +container as black or white background. + + align:start position:0% +container as black or white background. + + + align:start position:0% +container as black or white background. +We shot reactions in the front with a + + align:start position:0% +We shot reactions in the front with a + + + align:start position:0% +We shot reactions in the front with a +Panasonic GH4 camera and a 100 mm micro + + align:start position:0% +Panasonic GH4 camera and a 100 mm micro + + + align:start position:0% +Panasonic GH4 camera and a 100 mm micro +lens. Older reactions were shot in a + + align:start position:0% +lens. Older reactions were shot in a + + + align:start position:0% +lens. Older reactions were shot in a +normal lab with fluorescent lights. + + align:start position:0% +normal lab with fluorescent lights. + + + align:start position:0% +normal lab with fluorescent lights. +Because the LED panels were so much + + align:start position:0% +Because the LED panels were so much + + + align:start position:0% +Because the LED panels were so much +brighter than the fluorescent lights, we + + align:start position:0% +brighter than the fluorescent lights, we + + + align:start position:0% +brighter than the fluorescent lights, we +typically left them + + align:start position:0% +typically left them + + + align:start position:0% +typically left them +on. In this segment, we are showing a + + align:start position:0% +on. In this segment, we are showing a + + + align:start position:0% +on. In this segment, we are showing a +few crystallization processes, including + + align:start position:0% +few crystallization processes, including + + + align:start position:0% +few crystallization processes, including +crystallization of copper sulfate, + + align:start position:0% +crystallization of copper sulfate, + + + align:start position:0% +crystallization of copper sulfate, +sodium cell sulfate, and two more. We + + align:start position:0% +sodium cell sulfate, and two more. We + + + align:start position:0% +sodium cell sulfate, and two more. We +chose crystallization processes that are + + align:start position:0% +chose crystallization processes that are + + + align:start position:0% +chose crystallization processes that are +fast enough so that we could suit in + + align:start position:0% +fast enough so that we could suit in + + + align:start position:0% +fast enough so that we could suit in +real time and speed them up in editing. + + align:start position:0% +real time and speed them up in editing. + + + align:start position:0% +real time and speed them up in editing. +We did not select crystallization + + align:start position:0% +We did not select crystallization + + + align:start position:0% +We did not select crystallization +process that could take hours or days to + + align:start position:0% +process that could take hours or days to + + + align:start position:0% +process that could take hours or days to +form large crystals. For those + + align:start position:0% + + + + align:start position:0% + +templating and exposure have to be + + align:start position:0% +templating and exposure have to be + + + align:start position:0% +templating and exposure have to be +carefully controlled to avoid flicker in + + align:start position:0% +carefully controlled to avoid flicker in + + + align:start position:0% +carefully controlled to avoid flicker in +the final video. + + align:start position:0% +the final video. + + + align:start position:0% +the final video. +Finally, in this segment, we are showing + + align:start position:0% +Finally, in this segment, we are showing + + + align:start position:0% +Finally, in this segment, we are showing +a few bubbling reactions such as zinc + + align:start position:0% +a few bubbling reactions such as zinc + + + align:start position:0% +a few bubbling reactions such as zinc +metal reacts with hydrochloric acid to + + align:start position:0% +metal reacts with hydrochloric acid to + + + align:start position:0% +metal reacts with hydrochloric acid to +form hydrogen bubbles. These reactions + + align:start position:0% +form hydrogen bubbles. These reactions + + + align:start position:0% +form hydrogen bubbles. These reactions +were fast and usually we did not speed + + align:start position:0% +were fast and usually we did not speed + + + align:start position:0% +were fast and usually we did not speed +them up in + + align:start position:0% +them up in + + + align:start position:0% +them up in +editing. Overlet setup work well for + + align:start position:0% +editing. Overlet setup work well for + + + align:start position:0% +editing. Overlet setup work well for +bubbles. The white highlights on the + + align:start position:0% +bubbles. The white highlights on the + + + align:start position:0% +bubbles. The white highlights on the +right and left side of the bubbles are + + align:start position:0% +right and left side of the bubbles are + + + align:start position:0% +right and left side of the bubbles are +the reflection of the two LED panels. + + align:start position:0% +the reflection of the two LED panels. + + + align:start position:0% +the reflection of the two LED panels. +These highlights gave bubbles a very + + align:start position:0% +These highlights gave bubbles a very + + + align:start position:0% +These highlights gave bubbles a very +interesting look. \ No newline at end of file diff --git a/spY5kl_EYDU.txt b/spY5kl_EYDU.txt new file mode 100644 index 0000000000000000000000000000000000000000..d65b7613a0a02f3bb4b5908131b55d42d315ed59 --- /dev/null +++ b/spY5kl_EYDU.txt @@ -0,0 +1,9099 @@ +align:start position:0% + +the main topic in this part is really + + align:start position:0% +the main topic in this part is really + + + align:start position:0% +the main topic in this part is really +open economy and uh so we extended the + + align:start position:0% +open economy and uh so we extended the + + + align:start position:0% +open economy and uh so we extended the +eslm mo uh we did not bring in we we + + align:start position:0% +eslm mo uh we did not bring in we we + + + align:start position:0% +eslm mo uh we did not bring in we we +again shut down price changes so we said + + align:start position:0% +again shut down price changes so we said + + + align:start position:0% +again shut down price changes so we said +uh pric is completely fixed no Philips + + align:start position:0% +uh pric is completely fixed no Philips + + + align:start position:0% +uh pric is completely fixed no Philips +curve here so we expanded the eslm model + + align:start position:0% +curve here so we expanded the eslm model + + + align:start position:0% +curve here so we expanded the eslm model +to add this open E economy Dimension and + + align:start position:0% +to add this open E economy Dimension and + + + align:start position:0% +to add this open E economy Dimension and +so we start from the same aggregate + + align:start position:0% +so we start from the same aggregate + + + align:start position:0% +so we start from the same aggregate +demand function that we had in close + + align:start position:0% +demand function that we had in close + + + align:start position:0% +demand function that we had in close +economy consumption plus investment plus + + align:start position:0% +economy consumption plus investment plus + + + align:start position:0% +economy consumption plus investment plus +government expenditure but now we have + + align:start position:0% +government expenditure but now we have + + + align:start position:0% +government expenditure but now we have +to draw a distinction between Demand by + + align:start position:0% +to draw a distinction between Demand by + + + align:start position:0% +to draw a distinction between Demand by +domestic households companies and the + + align:start position:0% +domestic households companies and the + + + align:start position:0% +domestic households companies and the +government and the demand for + + align:start position:0% +government and the demand for + + + align:start position:0% +government and the demand for +domestically produced goods and so Z is + + align:start position:0% +domestically produced goods and so Z is + + + align:start position:0% +domestically produced goods and so Z is +the demand domestically produced Goods + + align:start position:0% +the demand domestically produced Goods + + + align:start position:0% +the demand domestically produced Goods +which is equal to demand plus the demand + + align:start position:0% +which is equal to demand plus the demand + + + align:start position:0% +which is equal to demand plus the demand +that foreigners have for the goods + + align:start position:0% +that foreigners have for the goods + + + align:start position:0% +that foreigners have for the goods +produces at home minus the Imports that + + align:start position:0% +produces at home minus the Imports that + + + align:start position:0% +produces at home minus the Imports that +part of that expenditure that is going + + align:start position:0% +part of that expenditure that is going + + + align:start position:0% +part of that expenditure that is going +to Imports that means Goods produced by + + align:start position:0% +to Imports that means Goods produced by + + + align:start position:0% +to Imports that means Goods produced by +other + + align:start position:0% +other + + + align:start position:0% +other +countries um so the new behavioral + + align:start position:0% +countries um so the new behavioral + + + align:start position:0% +countries um so the new behavioral +functions here where the export function + + align:start position:0% +functions here where the export function + + + align:start position:0% +functions here where the export function +and the import function uh export is + + align:start position:0% +and the import function uh export is + + + align:start position:0% +and the import function uh export is +increasing in foreign output more income + + align:start position:0% +increasing in foreign output more income + + + align:start position:0% +increasing in foreign output more income +abroad will lead to more Imports by them + + align:start position:0% +abroad will lead to more Imports by them + + + align:start position:0% +abroad will lead to more Imports by them +which means more export for home home + + align:start position:0% +which means more export for home home + + + align:start position:0% +which means more export for home home +and the it's decreasing on with respect + + align:start position:0% +and the it's decreasing on with respect + + + align:start position:0% +and the it's decreasing on with respect +to the exchange rate real exchange rate + + align:start position:0% +to the exchange rate real exchange rate + + + align:start position:0% +to the exchange rate real exchange rate +and nominal exchange rate will be the + + align:start position:0% +and nominal exchange rate will be the + + + align:start position:0% +and nominal exchange rate will be the +same here since we have fully sticky + + align:start position:0% +same here since we have fully sticky + + + align:start position:0% +same here since we have fully sticky +prices but + + align:start position:0% +prices but + + + align:start position:0% +prices but +H if if the real exchange it appreciat + + align:start position:0% +H if if the real exchange it appreciat + + + align:start position:0% +H if if the real exchange it appreciat +that means domestic goods are more + + align:start position:0% +that means domestic goods are more + + + align:start position:0% +that means domestic goods are more +expensive it means exports are less + + align:start position:0% +expensive it means exports are less + + + align:start position:0% +expensive it means exports are less +foreigners are going to buy less of our + + align:start position:0% +foreigners are going to buy less of our + + + align:start position:0% +foreigners are going to buy less of our +Goods conversely for imports is like the + + align:start position:0% +Goods conversely for imports is like the + + + align:start position:0% +Goods conversely for imports is like the +exports of the other country means that + + align:start position:0% +exports of the other country means that + + + align:start position:0% +exports of the other country means that +if domestic output goes up then then + + align:start position:0% +if domestic output goes up then then + + + align:start position:0% +if domestic output goes up then then +there will be more purchases of foreign + + align:start position:0% +there will be more purchases of foreign + + + align:start position:0% +there will be more purchases of foreign +foreign er er goods and if the exchange + + align:start position:0% +foreign er er goods and if the exchange + + + align:start position:0% +foreign er er goods and if the exchange +is appreciate means also that foreign + + align:start position:0% +is appreciate means also that foreign + + + align:start position:0% +is appreciate means also that foreign +goods are cheaper for us and therefore + + align:start position:0% +goods are cheaper for us and therefore + + + align:start position:0% +goods are cheaper for us and therefore +we import more okay so positive so those + + align:start position:0% +we import more okay so positive so those + + + align:start position:0% +we import more okay so positive so those +were those were the two new behavioral + + align:start position:0% +were those were the two new behavioral + + + align:start position:0% +were those were the two new behavioral +functions in the in the Goods Market + + align:start position:0% +functions in the in the Goods Market + + + align:start position:0% +functions in the in the Goods Market +expanded to include an open economy and + + align:start position:0% +expanded to include an open economy and + + + align:start position:0% +expanded to include an open economy and +that had implications for the diagram + + align:start position:0% +that had implications for the diagram + + + align:start position:0% +that had implications for the diagram +that we had in lecture three or so to + + align:start position:0% +that we had in lecture three or so to + + + align:start position:0% +that we had in lecture three or so to +determine equilibrium output ER you know + + align:start position:0% +determine equilibrium output ER you know + + + align:start position:0% +determine equilibrium output ER you know +we started from the same demand we had + + align:start position:0% +we started from the same demand we had + + + align:start position:0% +we started from the same demand we had +in close economy then we had to subtract + + align:start position:0% +in close economy then we had to subtract + + + align:start position:0% +in close economy then we had to subtract +in + + align:start position:0% +in + + + align:start position:0% +in +in import and uh and that is shift + + align:start position:0% +in import and uh and that is shift + + + align:start position:0% +in import and uh and that is shift +things down because we are now as part + + align:start position:0% +things down because we are now as part + + + align:start position:0% +things down because we are now as part +of the domestic demand that is going to + + align:start position:0% +of the domestic demand that is going to + + + align:start position:0% +of the domestic demand that is going to +foreign Goods not to domestic Goods but + + align:start position:0% +foreign Goods not to domestic Goods but + + + align:start position:0% +foreign Goods not to domestic Goods but +ER it's also rotates a curve because the + + align:start position:0% +ER it's also rotates a curve because the + + + align:start position:0% +ER it's also rotates a curve because the +higher is domestic income the more are + + align:start position:0% +higher is domestic income the more are + + + align:start position:0% +higher is domestic income the more are +the Imports uh that we do from the rest + + align:start position:0% +the Imports uh that we do from the rest + + + align:start position:0% +the Imports uh that we do from the rest +of the world now to that we have to add + + align:start position:0% +of the world now to that we have to add + + + align:start position:0% +of the world now to that we have to add +the export which are not a function of + + align:start position:0% +the export which are not a function of + + + align:start position:0% +the export which are not a function of +domestic output that's that's a parallel + + align:start position:0% +domestic output that's that's a parallel + + + align:start position:0% +domestic output that's that's a parallel +shift with respect to this curve no we + + align:start position:0% +shift with respect to this curve no we + + + align:start position:0% +shift with respect to this curve no we +go up up and and that gives us the ZZ + + align:start position:0% +go up up and and that gives us the ZZ + + + align:start position:0% +go up up and and that gives us the ZZ +curve which is what we call the demand + + align:start position:0% +curve which is what we call the demand + + + align:start position:0% +curve which is what we call the demand +for domestic Le domestically produced + + align:start position:0% +for domestic Le domestically produced + + + align:start position:0% +for domestic Le domestically produced +Goods now notice that the distance + + align:start position:0% +Goods now notice that the distance + + + align:start position:0% +Goods now notice that the distance +between the demand for domestically + + align:start position:0% +between the demand for domestically + + + align:start position:0% +between the demand for domestically +produced goods and the domestic demand + + align:start position:0% +produced goods and the domestic demand + + + align:start position:0% +produced goods and the domestic demand +for goods is what is the net export so + + align:start position:0% +for goods is what is the net export so + + + align:start position:0% +for goods is what is the net export so +the distance between z z and the D is + + align:start position:0% +the distance between z z and the D is + + + align:start position:0% +the distance between z z and the D is +the net export so in this point here for + + align:start position:0% + + + + align:start position:0% + +example ZZ is higher than DD which means + + align:start position:0% +example ZZ is higher than DD which means + + + align:start position:0% +example ZZ is higher than DD which means +that our exports are greater than our + + align:start position:0% +that our exports are greater than our + + + align:start position:0% +that our exports are greater than our +Imports and that's the reason you have a + + align:start position:0% +Imports and that's the reason you have a + + + align:start position:0% +Imports and that's the reason you have a +trade surplus at this point they're the + + align:start position:0% +trade surplus at this point they're the + + + align:start position:0% +trade surplus at this point they're the +same and that's the reason the trade + + align:start position:0% +same and that's the reason the trade + + + align:start position:0% +same and that's the reason the trade +account is balance and but over here + + align:start position:0% +account is balance and but over here + + + align:start position:0% +account is balance and but over here +Imports exceed exports and that's the + + align:start position:0% +Imports exceed exports and that's the + + + align:start position:0% +Imports exceed exports and that's the +reason we have a trade deficit + + align:start position:0% +reason we have a trade deficit + + + align:start position:0% +reason we have a trade deficit +okay I'm going to go very quickly so you + + align:start position:0% +okay I'm going to go very quickly so you + + + align:start position:0% +okay I'm going to go very quickly so you +you're in charge of stopping me I'm not + + align:start position:0% +you're in charge of stopping me I'm not + + + align:start position:0% +you're in charge of stopping me I'm not +going to ask you question just stop me + + align:start position:0% +going to ask you question just stop me + + + align:start position:0% +going to ask you question just stop me +if there's something that you need + + align:start position:0% +if there's something that you need + + + align:start position:0% +if there's something that you need +clarifications okay for so that's what + + align:start position:0% +clarifications okay for so that's what + + + align:start position:0% +clarifications okay for so that's what +the demand for domestically produced + + align:start position:0% +the demand for domestically produced + + + align:start position:0% +the demand for domestically produced +Goods now we're going to determine + + align:start position:0% +Goods now we're going to determine + + + align:start position:0% +Goods now we're going to determine +equilibrium output in this open e e omic + + align:start position:0% +equilibrium output in this open e e omic + + + align:start position:0% +equilibrium output in this open e e omic +context and that means you know + + align:start position:0% +context and that means you know + + + align:start position:0% +context and that means you know +aggregate demand has to be equal + + align:start position:0% +aggregate demand has to be equal + + + align:start position:0% +aggregate demand has to be equal +aggregate demand for domestically + + align:start position:0% +aggregate demand for domestically + + + align:start position:0% +aggregate demand for domestically +produced good has to be equal to output + + align:start position:0% +produced good has to be equal to output + + + align:start position:0% +produced good has to be equal to output +and that's what we do with the 45 degree + + align:start position:0% +and that's what we do with the 45 degree + + + align:start position:0% +and that's what we do with the 45 degree +line here and so where the 45 degree + + align:start position:0% +line here and so where the 45 degree + + + align:start position:0% +line here and so where the 45 degree +line intersect with this ZZ curve that's + + align:start position:0% +line intersect with this ZZ curve that's + + + align:start position:0% +line intersect with this ZZ curve that's +our equilibrium output now it happens + + align:start position:0% +our equilibrium output now it happens + + + align:start position:0% +our equilibrium output now it happens +that in this example that leads to a + + align:start position:0% +that in this example that leads to a + + + align:start position:0% +that in this example that leads to a +trade deficit but there's nothing here + + align:start position:0% +trade deficit but there's nothing here + + + align:start position:0% +trade deficit but there's nothing here +so we still determine equili output up + + align:start position:0% +so we still determine equili output up + + + align:start position:0% +so we still determine equili output up +here and then we read in this curve + + align:start position:0% +here and then we read in this curve + + + align:start position:0% +here and then we read in this curve +bottom curve what is implication for the + + align:start position:0% +bottom curve what is implication for the + + + align:start position:0% +bottom curve what is implication for the +traes deficit or Surplus + + align:start position:0% +traes deficit or Surplus + + + align:start position:0% +traes deficit or Surplus +okay H but the equilibrium condition + + align:start position:0% +okay H but the equilibrium condition + + + align:start position:0% +okay H but the equilibrium condition +important is that output domestically + + align:start position:0% +important is that output domestically + + + align:start position:0% +important is that output domestically +produc output has to be equal to the + + align:start position:0% +produc output has to be equal to the + + + align:start position:0% +produc output has to be equal to the +demand for domestically produced Goods + + align:start position:0% +demand for domestically produced Goods + + + align:start position:0% +demand for domestically produced Goods +not for total demand it's Dem demand for + + align:start position:0% +not for total demand it's Dem demand for + + + align:start position:0% +not for total demand it's Dem demand for +domestically produced Goods okay because + + align:start position:0% +domestically produced Goods okay because + + + align:start position:0% +domestically produced Goods okay because +this is a can model in which output is + + align:start position:0% +this is a can model in which output is + + + align:start position:0% +this is a can model in which output is +aggregate demand determined but it has + + align:start position:0% +aggregate demand determined but it has + + + align:start position:0% +aggregate demand determined but it has +to be aggregate demand for the things + + align:start position:0% +to be aggregate demand for the things + + + align:start position:0% +to be aggregate demand for the things +you're producing not AG demand for all + + align:start position:0% +you're producing not AG demand for all + + + align:start position:0% +you're producing not AG demand for all +Goods around the world okay good so then + + align:start position:0% +Goods around the world okay good so then + + + align:start position:0% +Goods around the world okay good so then +we did some experiments we said well + + align:start position:0% +we did some experiments we said well + + + align:start position:0% +we did some experiments we said well +suppose what happens in this open + + align:start position:0% +suppose what happens in this open + + + align:start position:0% +suppose what happens in this open +economy context if we increase + + align:start position:0% +economy context if we increase + + + align:start position:0% +economy context if we increase +government expenditure well the curent + + align:start position:0% +government expenditure well the curent + + + align:start position:0% +government expenditure well the curent +will shift up in exactly the same way as + + align:start position:0% +will shift up in exactly the same way as + + + align:start position:0% +will shift up in exactly the same way as +as in the close economy the difference + + align:start position:0% +as in the close economy the difference + + + align:start position:0% +as in the close economy the difference +will be in the multiplier though because + + align:start position:0% +will be in the multiplier though because + + + align:start position:0% +will be in the multiplier though because +as output goes up as a result of the + + align:start position:0% +as output goes up as a result of the + + + align:start position:0% +as output goes up as a result of the +expansionary aggregate demand that also + + align:start position:0% +expansionary aggregate demand that also + + + align:start position:0% +expansionary aggregate demand that also +means that domestic income will go up + + align:start position:0% +means that domestic income will go up + + + align:start position:0% +means that domestic income will go up +and and that means that Imports will go + + align:start position:0% +and and that means that Imports will go + + + align:start position:0% +and and that means that Imports will go +up and that's demand that will go for + + align:start position:0% +up and that's demand that will go for + + + align:start position:0% +up and that's demand that will go for +foreign goods and that's the reason the + + align:start position:0% +foreign goods and that's the reason the + + + align:start position:0% +foreign goods and that's the reason the +z z curve has a lower multiplier it's + + align:start position:0% +z z curve has a lower multiplier it's + + + align:start position:0% +z z curve has a lower multiplier it's +flatter than the DD curve okay still if + + align:start position:0% +flatter than the DD curve okay still if + + + align:start position:0% +flatter than the DD curve okay still if +we start for example with a trade + + align:start position:0% +we start for example with a trade + + + align:start position:0% +we start for example with a trade +balance since Imports are going to + + align:start position:0% +balance since Imports are going to + + + align:start position:0% +balance since Imports are going to +increase as a result of this + + align:start position:0% +increase as a result of this + + + align:start position:0% +increase as a result of this +expansionary fiscal policy we going end + + align:start position:0% +expansionary fiscal policy we going end + + + align:start position:0% +expansionary fiscal policy we going end +up with a trade deficit and that's the + + align:start position:0% +up with a trade deficit and that's the + + + align:start position:0% +up with a trade deficit and that's the +reason the response of output is less + + align:start position:0% +reason the response of output is less + + + align:start position:0% +reason the response of output is less +than close economies because part of + + align:start position:0% +than close economies because part of + + + align:start position:0% +than close economies because part of +that goes to foreign Goods conversely if + + align:start position:0% +that goes to foreign Goods conversely if + + + align:start position:0% +that goes to foreign Goods conversely if +this other country that is doing a + + align:start position:0% +this other country that is doing a + + + align:start position:0% +this other country that is doing a +expansion in fiscal policy or something + + align:start position:0% +expansion in fiscal policy or something + + + align:start position:0% +expansion in fiscal policy or something +that leads to higher output abroad wi + + align:start position:0% +that leads to higher output abroad wi + + + align:start position:0% +that leads to higher output abroad wi +star that's also expansionary for home + + align:start position:0% +star that's also expansionary for home + + + align:start position:0% +star that's also expansionary for home +because exports the export function goes + + align:start position:0% +because exports the export function goes + + + align:start position:0% +because exports the export function goes +up no and that leads to an increase in + + align:start position:0% +up no and that leads to an increase in + + + align:start position:0% +up no and that leads to an increase in +output ER still with lower multiplier + + align:start position:0% +output ER still with lower multiplier + + + align:start position:0% +output ER still with lower multiplier +because part of that increase in + + align:start position:0% +because part of that increase in + + + align:start position:0% +because part of that increase in +domestic output will go will go to + + align:start position:0% +domestic output will go will go to + + + align:start position:0% +domestic output will go will go to +Imports but the in this case unlike the + + align:start position:0% +Imports but the in this case unlike the + + + align:start position:0% +Imports but the in this case unlike the +other ones actually the current the the + + align:start position:0% +other ones actually the current the the + + + align:start position:0% +other ones actually the current the the +trade balance improves because it's been + + align:start position:0% +trade balance improves because it's been + + + align:start position:0% +trade balance improves because it's been +pulled by exports and so we at at impact + + align:start position:0% +pulled by exports and so we at at impact + + + align:start position:0% +pulled by exports and so we at at impact +we get a big increase in export which is + + align:start position:0% +we get a big increase in export which is + + + align:start position:0% +we get a big increase in export which is +the driver of increasable demand for + + align:start position:0% +the driver of increasable demand for + + + align:start position:0% +the driver of increasable demand for +domestically produced Goods and then as + + align:start position:0% +domestically produced Goods and then as + + + align:start position:0% +domestically produced Goods and then as +income goes up we undo some of that but + + align:start position:0% +income goes up we undo some of that but + + + align:start position:0% +income goes up we undo some of that but +you end up with sort of higher high + + align:start position:0% +you end up with sort of higher high + + + align:start position:0% +you end up with sort of higher high +higher better trade deficit better trade + + align:start position:0% +higher better trade deficit better trade + + + align:start position:0% +higher better trade deficit better trade +surpluses than than in the case in which + + align:start position:0% +surpluses than than in the case in which + + + align:start position:0% +surpluses than than in the case in which +you induce the the expansion in agre + + align:start position:0% + + + + align:start position:0% + +demand uh then the last step there was H + + align:start position:0% +demand uh then the last step there was H + + + align:start position:0% +demand uh then the last step there was H +to look at the role of the exchange rate + + align:start position:0% +to look at the role of the exchange rate + + + align:start position:0% +to look at the role of the exchange rate +and uh where we said is we're going to + + align:start position:0% +and uh where we said is we're going to + + + align:start position:0% +and uh where we said is we're going to +make some assumptions that I promise you + + align:start position:0% +make some assumptions that I promise you + + + align:start position:0% +make some assumptions that I promise you +and and I now read the quiz so I I I I + + align:start position:0% +and and I now read the quiz so I I I I + + + align:start position:0% +and and I now read the quiz so I I I I +guarantee you I honor This Promise H + + align:start position:0% +guarantee you I honor This Promise H + + + align:start position:0% +guarantee you I honor This Promise H +nothing weird will happen meaning if if + + align:start position:0% +nothing weird will happen meaning if if + + + align:start position:0% +nothing weird will happen meaning if if +our Goods gets more expensive that means + + align:start position:0% +our Goods gets more expensive that means + + + align:start position:0% +our Goods gets more expensive that means +that net exports will be worse and and + + align:start position:0% +that net exports will be worse and and + + + align:start position:0% +that net exports will be worse and and +if if H for two reasons for at least for + + align:start position:0% +if if H for two reasons for at least for + + + align:start position:0% +if if H for two reasons for at least for +at least one reason but it could be too + + align:start position:0% +at least one reason but it could be too + + + align:start position:0% +at least one reason but it could be too +if if if the exchange rate goes up then + + align:start position:0% +if if if the exchange rate goes up then + + + align:start position:0% +if if if the exchange rate goes up then +there's going to be less exports at any + + align:start position:0% +there's going to be less exports at any + + + align:start position:0% +there's going to be less exports at any +given level of foreign income that will + + align:start position:0% +given level of foreign income that will + + + align:start position:0% +given level of foreign income that will +worsen the net export and then we were + + align:start position:0% +worsen the net export and then we were + + + align:start position:0% +worsen the net export and then we were +going to tend to import more now that + + align:start position:0% +going to tend to import more now that + + + align:start position:0% +going to tend to import more now that +will be parti should upset for the fact + + align:start position:0% +will be parti should upset for the fact + + + align:start position:0% +will be parti should upset for the fact +that you can buy more with the same + + align:start position:0% +that you can buy more with the same + + + align:start position:0% +that you can buy more with the same +amount of dollars H but we said we're + + align:start position:0% +amount of dollars H but we said we're + + + align:start position:0% +amount of dollars H but we said we're +going to impose conditions such that the + + align:start position:0% +going to impose conditions such that the + + + align:start position:0% +going to impose conditions such that the +positive the negative effect of an + + align:start position:0% +positive the negative effect of an + + + align:start position:0% +positive the negative effect of an +appreciation on that export always + + align:start position:0% +appreciation on that export always + + + align:start position:0% +appreciation on that export always +dominates and again in your quiz you're + + align:start position:0% +dominates and again in your quiz you're + + + align:start position:0% +dominates and again in your quiz you're +going to have a situation like that and + + align:start position:0% +going to have a situation like that and + + + align:start position:0% +going to have a situation like that and +that will be the + + align:start position:0% +that will be the + + + align:start position:0% +that will be the +case so don't think that that we're + + align:start position:0% +case so don't think that that we're + + + align:start position:0% +case so don't think that that we're +trying to trick you anything this will + + align:start position:0% +trying to trick you anything this will + + + align:start position:0% +trying to trick you anything this will +hold okay the the point of this being + + align:start position:0% +hold okay the the point of this being + + + align:start position:0% +hold okay the the point of this being +that you know that that uh + + align:start position:0% +that you know that that uh + + + align:start position:0% +that you know that that uh +depreciating your + + align:start position:0% +depreciating your + + + align:start position:0% +depreciating your +currency you know making your goods less + + align:start position:0% +currency you know making your goods less + + + align:start position:0% +currency you know making your goods less +expensive ER is equivalent to will + + align:start position:0% +expensive ER is equivalent to will + + + align:start position:0% +expensive ER is equivalent to will +produce an a response equivalent to what + + align:start position:0% +produce an a response equivalent to what + + + align:start position:0% +produce an a response equivalent to what +you get here out of an increasing y star + + align:start position:0% +you get here out of an increasing y star + + + align:start position:0% +you get here out of an increasing y star +no because that's export will go + + align:start position:0% +no because that's export will go + + + align:start position:0% +no because that's export will go +up and you're going to get all the shift + + align:start position:0% +up and you're going to get all the shift + + + align:start position:0% +up and you're going to get all the shift +net export function will go up that will + + align:start position:0% +net export function will go up that will + + + align:start position:0% +net export function will go up that will +increase aggregate demand and so on so + + align:start position:0% +increase aggregate demand and so on so + + + align:start position:0% +increase aggregate demand and so on so +that's kind things that countries want + + align:start position:0% +that's kind things that countries want + + + align:start position:0% +that's kind things that countries want +to typically when they're in a recession + + align:start position:0% +to typically when they're in a recession + + + align:start position:0% +to typically when they're in a recession +and so on then that was an introduction + + align:start position:0% +and so on then that was an introduction + + + align:start position:0% +and so on then that was an introduction +to the most important lecture in this + + align:start position:0% +to the most important lecture in this + + + align:start position:0% +to the most important lecture in this +part of + + align:start position:0% +part of + + + align:start position:0% +part of +the course which is the Mandel flaming + + align:start position:0% +the course which is the Mandel flaming + + + align:start position:0% +the course which is the Mandel flaming +model and I I I promise you that you + + align:start position:0% +model and I I I promise you that you + + + align:start position:0% +model and I I I promise you that you +would get 70% at least in the quiz and I + + align:start position:0% +would get 70% at least in the quiz and I + + + align:start position:0% +would get 70% at least in the quiz and I +already read the quiz so I tell you + + align:start position:0% +already read the quiz so I tell you + + + align:start position:0% +already read the quiz so I tell you +there is at least 70% of your points + + align:start position:0% +there is at least 70% of your points + + + align:start position:0% +there is at least 70% of your points +have to do with this model so you better + + align:start position:0% +have to do with this model so you better + + + align:start position:0% +have to do with this model so you better +understand it very well you do every + + align:start position:0% +understand it very well you do every + + + align:start position:0% +understand it very well you do every +single comparative Statics that you can + + align:start position:0% +single comparative Statics that you can + + + align:start position:0% +single comparative Statics that you can +imagine with this Mo and then you'll get + + align:start position:0% +imagine with this Mo and then you'll get + + + align:start position:0% +imagine with this Mo and then you'll get +70% at least I think you get 73 actually + + align:start position:0% +70% at least I think you get 73 actually + + + align:start position:0% +70% at least I think you get 73 actually +but but but that's + + align:start position:0% +but but but that's + + + align:start position:0% +but but but that's +the so what's this well the Mandel + + align:start position:0% +the so what's this well the Mandel + + + align:start position:0% +the so what's this well the Mandel +flaming model is simply what I just + + align:start position:0% +flaming model is simply what I just + + + align:start position:0% +flaming model is simply what I just +showed you is the good market + + align:start position:0% +showed you is the good market + + + align:start position:0% +showed you is the good market +equilibrium no that's the but with an + + align:start position:0% +equilibrium no that's the but with an + + + align:start position:0% +equilibrium no that's the but with an +endogenous exchange rate and uh so we we + + align:start position:0% +endogenous exchange rate and uh so we we + + + align:start position:0% +endogenous exchange rate and uh so we we +rewrote to say since we're assuming + + align:start position:0% +rewrote to say since we're assuming + + + align:start position:0% +rewrote to say since we're assuming +compettive sticky prices we can replace + + align:start position:0% +compettive sticky prices we can replace + + + align:start position:0% +compettive sticky prices we can replace +the real Exchange by the nominal + + align:start position:0% +the real Exchange by the nominal + + + align:start position:0% +the real Exchange by the nominal +exchange rate H but now we're going to + + align:start position:0% +exchange rate H but now we're going to + + + align:start position:0% +exchange rate H but now we're going to +endogenize the exchange rate and and and + + align:start position:0% +endogenize the exchange rate and and and + + + align:start position:0% +endogenize the exchange rate and and and +for that we're going to use the uncover + + align:start position:0% +for that we're going to use the uncover + + + align:start position:0% +for that we're going to use the uncover +in parity condition this a condition you + + align:start position:0% +in parity condition this a condition you + + + align:start position:0% +in parity condition this a condition you +should understand very well as well okay + + align:start position:0% +should understand very well as well okay + + + align:start position:0% +should understand very well as well okay +so that tells you essentially that the + + align:start position:0% +so that tells you essentially that the + + + align:start position:0% +so that tells you essentially that the +expected Return of the two bonds the + + align:start position:0% +expected Return of the two bonds the + + + align:start position:0% +expected Return of the two bonds the +bonds issuing foreign currency and + + align:start position:0% +bonds issuing foreign currency and + + + align:start position:0% +bonds issuing foreign currency and +domestic currency have to be the same + + align:start position:0% +domestic currency have to be the same + + + align:start position:0% +domestic currency have to be the same +the Spector return have to be the same + + align:start position:0% +the Spector return have to be the same + + + align:start position:0% +the Spector return have to be the same +okay and this condition ensures that + + align:start position:0% +okay and this condition ensures that + + + align:start position:0% +okay and this condition ensures that +because if a country for example example + + align:start position:0% +because if a country for example example + + + align:start position:0% +because if a country for example example +if the domestic interest rate is higher + + align:start position:0% +if the domestic interest rate is higher + + + align:start position:0% +if the domestic interest rate is higher +than the international interest rate you + + align:start position:0% +than the international interest rate you + + + align:start position:0% +than the international interest rate you +need to expect a depreciation of the + + align:start position:0% +need to expect a depreciation of the + + + align:start position:0% +need to expect a depreciation of the +current currency otherwise the expected + + align:start position:0% +current currency otherwise the expected + + + align:start position:0% +current currency otherwise the expected +return would not be the same okay and + + align:start position:0% +return would not be the same okay and + + + align:start position:0% +return would not be the same okay and +that's the reason when we add the + + align:start position:0% +that's the reason when we add the + + + align:start position:0% +that's the reason when we add the +assumption that the Spector exchanges is + + align:start position:0% +assumption that the Spector exchanges is + + + align:start position:0% +assumption that the Spector exchanges is +fixed at least temporarily H then an + + align:start position:0% +fixed at least temporarily H then an + + + align:start position:0% +fixed at least temporarily H then an +increase in the interest rate leads to + + align:start position:0% +increase in the interest rate leads to + + + align:start position:0% +increase in the interest rate leads to +an appreciation of the exchange rate why + + align:start position:0% +an appreciation of the exchange rate why + + + align:start position:0% +an appreciation of the exchange rate why +because that if the exchange rate + + align:start position:0% +because that if the exchange rate + + + align:start position:0% +because that if the exchange rate +appreciate but the expected exchange + + align:start position:0% +appreciate but the expected exchange + + + align:start position:0% +appreciate but the expected exchange +rate stays put that that means the + + align:start position:0% +rate stays put that that means the + + + align:start position:0% +rate stays put that that means the +expected appreciation will have to be + + align:start position:0% +expected appreciation will have to be + + + align:start position:0% +expected appreciation will have to be +undone and that means that leads to + + align:start position:0% +undone and that means that leads to + + + align:start position:0% +undone and that means that leads to +unexpected depreciation okay so that's + + align:start position:0% +unexpected depreciation okay so that's + + + align:start position:0% +unexpected depreciation okay so that's +very important okay so here you have + + align:start position:0% +very important okay so here you have + + + align:start position:0% +very important okay so here you have +therefore you need to understand this + + align:start position:0% +therefore you need to understand this + + + align:start position:0% +therefore you need to understand this +know that forgiv expectation of the + + align:start position:0% +know that forgiv expectation of the + + + align:start position:0% +know that forgiv expectation of the +exchange rate and increasing domestic + + align:start position:0% +exchange rate and increasing domestic + + + align:start position:0% +exchange rate and increasing domestic +interest rate appreciates the domestic + + align:start position:0% +interest rate appreciates the domestic + + + align:start position:0% +interest rate appreciates the domestic +currency and and increasing the foreign + + align:start position:0% +currency and and increasing the foreign + + + align:start position:0% +currency and and increasing the foreign +interest rate without us matching it + + align:start position:0% +interest rate without us matching it + + + align:start position:0% +interest rate without us matching it +will lead to a depreciation of the + + align:start position:0% +will lead to a depreciation of the + + + align:start position:0% +will lead to a depreciation of the +current of of the domestic currency okay + + align:start position:0% +current of of the domestic currency okay + + + align:start position:0% +current of of the domestic currency okay +so that's what you have there that's + + align:start position:0% +so that's what you have there that's + + + align:start position:0% +so that's what you have there that's +important + + align:start position:0% + + + + align:start position:0% + +important now notice that if the + + align:start position:0% +important now notice that if the + + + align:start position:0% +important now notice that if the +expected exchange rate goes + + align:start position:0% +expected exchange rate goes + + + align:start position:0% +expected exchange rate goes +up and the interest rates do not change + + align:start position:0% +up and the interest rates do not change + + + align:start position:0% +up and the interest rates do not change +then the current exchanger has to go up + + align:start position:0% +then the current exchanger has to go up + + + align:start position:0% +then the current exchanger has to go up +because if it didn't then you would have + + align:start position:0% +because if it didn't then you would have + + + align:start position:0% +because if it didn't then you would have +an expected capital gain out of the + + align:start position:0% +an expected capital gain out of the + + + align:start position:0% +an expected capital gain out of the +currency and expected appreciation and + + align:start position:0% +currency and expected appreciation and + + + align:start position:0% +currency and expected appreciation and +that would add to the expected return of + + align:start position:0% +that would add to the expected return of + + + align:start position:0% +that would add to the expected return of +own owning a domestic bones okay + + align:start position:0% +own owning a domestic bones okay + + + align:start position:0% +own owning a domestic bones okay +good so we characterize that interest + + align:start position:0% +good so we characterize that interest + + + align:start position:0% +good so we characterize that interest +parity condition as follows we said well + + align:start position:0% +parity condition as follows we said well + + + align:start position:0% +parity condition as follows we said well +look this this here we're plotting the + + align:start position:0% +look this this here we're plotting the + + + align:start position:0% +look this this here we're plotting the +domestic interest rate here we're + + align:start position:0% +domestic interest rate here we're + + + align:start position:0% +domestic interest rate here we're +putting the current exchange rate and + + align:start position:0% +putting the current exchange rate and + + + align:start position:0% +putting the current exchange rate and +what we're marking in this picture this + + align:start position:0% +what we're marking in this picture this + + + align:start position:0% +what we're marking in this picture this +is the curve that traces the uip the and + + align:start position:0% +is the curve that traces the uip the and + + + align:start position:0% +is the curve that traces the uip the and +cover by the condition and naturally + + align:start position:0% +cover by the condition and naturally + + + align:start position:0% +cover by the condition and naturally +when the domestic interest rate is equal + + align:start position:0% +when the domestic interest rate is equal + + + align:start position:0% +when the domestic interest rate is equal +to International interest rate then it + + align:start position:0% +to International interest rate then it + + + align:start position:0% +to International interest rate then it +has to be the case that the exchange + + align:start position:0% +has to be the case that the exchange + + + align:start position:0% +has to be the case that the exchange +rate is at the same level as the + + align:start position:0% +rate is at the same level as the + + + align:start position:0% +rate is at the same level as the +expected exchange no if that is equal to + + align:start position:0% +expected exchange no if that is equal to + + + align:start position:0% +expected exchange no if that is equal to +that so if we're here then we know that + + align:start position:0% +that so if we're here then we know that + + + align:start position:0% +that so if we're here then we know that +a point in that curve is that in which + + align:start position:0% +a point in that curve is that in which + + + align:start position:0% +a point in that curve is that in which +the exchange rate is equal to the + + align:start position:0% +the exchange rate is equal to the + + + align:start position:0% +the exchange rate is equal to the +expected exchange rate okay that's what + + align:start position:0% +expected exchange rate okay that's what + + + align:start position:0% +expected exchange rate okay that's what +we have + + align:start position:0% +we have + + + align:start position:0% +we have +yeah good so you should understand this + + align:start position:0% +yeah good so you should understand this + + + align:start position:0% +yeah good so you should understand this +curve and and know what moves it here + + align:start position:0% +curve and and know what moves it here + + + align:start position:0% +curve and and know what moves it here +it's very clear what moves it no if + + align:start position:0% +it's very clear what moves it no if + + + align:start position:0% +it's very clear what moves it no if +there are two things that can move this + + align:start position:0% +there are two things that can move this + + + align:start position:0% +there are two things that can move this +this curve here one is a change in I + + align:start position:0% +this curve here one is a change in I + + + align:start position:0% +this curve here one is a change in I +star the other one is a change in + + align:start position:0% +star the other one is a change in + + + align:start position:0% +star the other one is a change in +expected exchange rate if what happens + + align:start position:0% +expected exchange rate if what happens + + + align:start position:0% +expected exchange rate if what happens +if the is star goes + + align:start position:0% +if the is star goes + + + align:start position:0% +if the is star goes +up well you know that the new new the + + align:start position:0% +up well you know that the new new the + + + align:start position:0% +up well you know that the new new the +uip will shift but you do know that the + + align:start position:0% +uip will shift but you do know that the + + + align:start position:0% +uip will shift but you do know that the +next the The Point equivalent to that + + align:start position:0% +next the The Point equivalent to that + + + align:start position:0% +next the The Point equivalent to that +that is one in which exchange rate is + + align:start position:0% +that is one in which exchange rate is + + + align:start position:0% +that is one in which exchange rate is +equal to expected exchange rate we have + + align:start position:0% +equal to expected exchange rate we have + + + align:start position:0% +equal to expected exchange rate we have +to have a higher interest rate domestic + + align:start position:0% +to have a higher interest rate domestic + + + align:start position:0% +to have a higher interest rate domestic +interest rate no because if I'm bringing + + align:start position:0% +interest rate no because if I'm bringing + + + align:start position:0% +interest rate no because if I'm bringing +this up and I want to still look at the + + align:start position:0% +this up and I want to still look at the + + + align:start position:0% +this up and I want to still look at the +point in which e is equal to expected + + align:start position:0% +point in which e is equal to expected + + + align:start position:0% +point in which e is equal to expected +exchange rate then I have to move I up + + align:start position:0% +exchange rate then I have to move I up + + + align:start position:0% +exchange rate then I have to move I up +by the same amount and so I know that + + align:start position:0% +by the same amount and so I know that + + + align:start position:0% +by the same amount and so I know that +this curve when when is Star goes up + + align:start position:0% +this curve when when is Star goes up + + + align:start position:0% +this curve when when is Star goes up +this curve moves up or to the left you + + align:start position:0% +this curve moves up or to the left you + + + align:start position:0% +this curve moves up or to the left you +pick which way you analyze + + align:start position:0% +pick which way you analyze + + + align:start position:0% +pick which way you analyze +okay now what about the expected + + align:start position:0% +okay now what about the expected + + + align:start position:0% +okay now what about the expected +exchange rate well if the expected + + align:start position:0% +exchange rate well if the expected + + + align:start position:0% +exchange rate well if the expected +exchange rate goes + + align:start position:0% +exchange rate goes + + + align:start position:0% +exchange rate goes +up if the spected exchange goes up and + + align:start position:0% +up if the spected exchange goes up and + + + align:start position:0% +up if the spected exchange goes up and +the international interest hasn't gone + + align:start position:0% +the international interest hasn't gone + + + align:start position:0% +the international interest hasn't gone +up H so if this moves to to the spected + + align:start position:0% +up H so if this moves to to the spected + + + align:start position:0% +up H so if this moves to to the spected +exchanger moves to the right then and + + align:start position:0% +exchanger moves to the right then and + + + align:start position:0% +exchanger moves to the right then and +the and the and the domestic interest + + align:start position:0% +the and the and the domestic interest + + + align:start position:0% +the and the and the domestic interest +doesn't go up then that means that the + + align:start position:0% +doesn't go up then that means that the + + + align:start position:0% +doesn't go up then that means that the +current exchanger will have to also go + + align:start position:0% +current exchanger will have to also go + + + align:start position:0% +current exchanger will have to also go +up okay so that means H if this goes up + + align:start position:0% +up okay so that means H if this goes up + + + align:start position:0% +up okay so that means H if this goes up +then at an interest rate equal to the + + align:start position:0% +then at an interest rate equal to the + + + align:start position:0% +then at an interest rate equal to the +the international interest rate so let's + + align:start position:0% +the international interest rate so let's + + + align:start position:0% +the international interest rate so let's +tra look in this direction then we have + + align:start position:0% +tra look in this direction then we have + + + align:start position:0% +tra look in this direction then we have +a point around here okay if if that + + align:start position:0% +a point around here okay if if that + + + align:start position:0% +a point around here okay if if that +wasn't the cas case then you would + + align:start position:0% +wasn't the cas case then you would + + + align:start position:0% +wasn't the cas case then you would +respecting an appreciation and then + + align:start position:0% +respecting an appreciation and then + + + align:start position:0% +respecting an appreciation and then +again would be inconsistent with + + align:start position:0% +again would be inconsistent with + + + align:start position:0% +again would be inconsistent with +h the uip then we put things together so + + align:start position:0% +h the uip then we put things together so + + + align:start position:0% +h the uip then we put things together so +what we did is we replace we use the uip + + align:start position:0% +what we did is we replace we use the uip + + + align:start position:0% +what we did is we replace we use the uip +to replace exchange rate there and now + + align:start position:0% +to replace exchange rate there and now + + + align:start position:0% +to replace exchange rate there and now +we get this expression in the net export + + align:start position:0% +we get this expression in the net export + + + align:start position:0% +we get this expression in the net export +function now we the LM is exactly the + + align:start position:0% +function now we the LM is exactly the + + + align:start position:0% +function now we the LM is exactly the +same as before we we have + + align:start position:0% +same as before we we have + + + align:start position:0% +same as before we we have +a the Central Bank sets the interest + + align:start position:0% +a the Central Bank sets the interest + + + align:start position:0% +a the Central Bank sets the interest +rate here I'm writing it in terms of the + + align:start position:0% +rate here I'm writing it in terms of the + + + align:start position:0% +rate here I'm writing it in terms of the +nominal interest rate I think in the + + align:start position:0% +nominal interest rate I think in the + + + align:start position:0% +nominal interest rate I think in the +quiz we wrote it in terms of the real + + align:start position:0% +quiz we wrote it in terms of the real + + + align:start position:0% +quiz we wrote it in terms of the real +interest rate but it's the same because + + align:start position:0% +interest rate but it's the same because + + + align:start position:0% +interest rate but it's the same because +prices is equal to are fixed so real and + + align:start position:0% +prices is equal to are fixed so real and + + + align:start position:0% +prices is equal to are fixed so real and +nominal interest rate are exactly the + + align:start position:0% +nominal interest rate are exactly the + + + align:start position:0% +nominal interest rate are exactly the +same + + align:start position:0% +same + + + align:start position:0% +same +yeah is the xais the expected exchange + + align:start position:0% +yeah is the xais the expected exchange + + + align:start position:0% +yeah is the xais the expected exchange +rate no is the actual exchange rate the + + align:start position:0% +rate no is the actual exchange rate the + + + align:start position:0% +rate no is the actual exchange rate the +spected exchange rate is in this curve + + align:start position:0% +spected exchange rate is in this curve + + + align:start position:0% +spected exchange rate is in this curve +here that is a parameter okay this + + align:start position:0% +here that is a parameter okay this + + + align:start position:0% +here that is a parameter okay this +happens to be a value of the current + + align:start position:0% +happens to be a value of the current + + + align:start position:0% +happens to be a value of the current +exchange equal to the spected exchange + + align:start position:0% +exchange equal to the spected exchange + + + align:start position:0% +exchange equal to the spected exchange +rate which is convenient to plot because + + align:start position:0% +rate which is convenient to plot because + + + align:start position:0% +rate which is convenient to plot because +that's also when the domestic interest + + align:start position:0% +that's also when the domestic interest + + + align:start position:0% +that's also when the domestic interest +rate which is what I'm putting here is + + align:start position:0% +rate which is what I'm putting here is + + + align:start position:0% +rate which is what I'm putting here is +equal to International interest rate + + align:start position:0% +equal to International interest rate + + + align:start position:0% +equal to International interest rate +that's all that I'm saying and then if + + align:start position:0% +that's all that I'm saying and then if + + + align:start position:0% +that's all that I'm saying and then if +you shift this to the + + align:start position:0% +you shift this to the + + + align:start position:0% +you shift this to the +right exchange rate up the expect exate + + align:start position:0% +right exchange rate up the expect exate + + + align:start position:0% +right exchange rate up the expect exate +up then I know that a new point in this + + align:start position:0% +up then I know that a new point in this + + + align:start position:0% +up then I know that a new point in this +curve has to have a higher current + + align:start position:0% +curve has to have a higher current + + + align:start position:0% +curve has to have a higher current +exchange rate so that I know I know that + + align:start position:0% +exchange rate so that I know I know that + + + align:start position:0% +exchange rate so that I know I know that +the equivalent to this point a is going + + align:start position:0% +the equivalent to this point a is going + + + align:start position:0% +the equivalent to this point a is going +to be to the right if you lower the + + align:start position:0% +to be to the right if you lower the + + + align:start position:0% +to be to the right if you lower the +foreign interest rate then what I know + + align:start position:0% +foreign interest rate then what I know + + + align:start position:0% +foreign interest rate then what I know +is that exactly that that the point at + + align:start position:0% +is that exactly that that the point at + + + align:start position:0% +is that exactly that that the point at +which exchange it is equal to expected + + align:start position:0% +which exchange it is equal to expected + + + align:start position:0% +which exchange it is equal to expected +exchange rate has to have a lower + + align:start position:0% +exchange rate has to have a lower + + + align:start position:0% +exchange rate has to have a lower +domestic interest rate so that means + + align:start position:0% +domestic interest rate so that means + + + align:start position:0% +domestic interest rate so that means +that I know that that that this point a + + align:start position:0% +that I know that that that this point a + + + align:start position:0% +that I know that that that this point a +will be around here which is like a + + align:start position:0% +will be around here which is like a + + + align:start position:0% +will be around here which is like a +shift to the right okay + + align:start position:0% + + + + align:start position:0% + +anyway so so as I said I was saying ER + + align:start position:0% +anyway so so as I said I was saying ER + + + align:start position:0% +anyway so so as I said I was saying ER +nominal real interest are the same I + + align:start position:0% +nominal real interest are the same I + + + align:start position:0% +nominal real interest are the same I +think in the in the quiz we wrote are + + align:start position:0% +think in the in the quiz we wrote are + + + align:start position:0% +think in the in the quiz we wrote are +there but it's the same same + + align:start position:0% +there but it's the same same + + + align:start position:0% +there but it's the same same +more so now you see that interest rate + + align:start position:0% +more so now you see that interest rate + + + align:start position:0% +more so now you see that interest rate +have two effects no h one is the + + align:start position:0% +have two effects no h one is the + + + align:start position:0% +have two effects no h one is the +traditional effect affects investment + + align:start position:0% +traditional effect affects investment + + + align:start position:0% +traditional effect affects investment +but it also affects exchange R so H an + + align:start position:0% +but it also affects exchange R so H an + + + align:start position:0% +but it also affects exchange R so H an +increas in the domestic interest rate + + align:start position:0% +increas in the domestic interest rate + + + align:start position:0% +increas in the domestic interest rate +now will will be doubly contractional in + + align:start position:0% +now will will be doubly contractional in + + + align:start position:0% +now will will be doubly contractional in +the sense that we lower domestic + + align:start position:0% +the sense that we lower domestic + + + align:start position:0% +the sense that we lower domestic +investment that reduces aggregate demand + + align:start position:0% +investment that reduces aggregate demand + + + align:start position:0% +investment that reduces aggregate demand +but at the same time it will also + + align:start position:0% +but at the same time it will also + + + align:start position:0% +but at the same time it will also +appreciate the exchange rate and + + align:start position:0% +appreciate the exchange rate and + + + align:start position:0% +appreciate the exchange rate and +therefore it will reduce net exports + + align:start position:0% +therefore it will reduce net exports + + + align:start position:0% +therefore it will reduce net exports +okay we're going to import more and + + align:start position:0% +okay we're going to import more and + + + align:start position:0% +okay we're going to import more and +Export less and that's also going to + + align:start position:0% +Export less and that's also going to + + + align:start position:0% +Export less and that's also going to +reduce aggregate demand so that's that's + + align:start position:0% +reduce aggregate demand so that's that's + + + align:start position:0% +reduce aggregate demand so that's that's +the those are the two effects so that's + + align:start position:0% +the those are the two effects so that's + + + align:start position:0% +the those are the two effects so that's +the contribution of the all this + + align:start position:0% +the contribution of the all this + + + align:start position:0% +the contribution of the all this +exchange rate block to our islm + + align:start position:0% +exchange rate block to our islm + + + align:start position:0% +exchange rate block to our islm +framework Mandel flaming is simply islm + + align:start position:0% +framework Mandel flaming is simply islm + + + align:start position:0% +framework Mandel flaming is simply islm +plus a a you know a uip condition and a + + align:start position:0% +plus a a you know a uip condition and a + + + align:start position:0% +plus a a you know a uip condition and a +net export function that's it + + align:start position:0% +net export function that's it + + + align:start position:0% +net export function that's it +so we put out now the two things + + align:start position:0% +so we put out now the two things + + + align:start position:0% +so we put out now the two things +together sort of a standard is islm now + + align:start position:0% +together sort of a standard is islm now + + + align:start position:0% +together sort of a standard is islm now +with different slope and so on because + + align:start position:0% +with different slope and so on because + + + align:start position:0% +with different slope and so on because +we have this net export function and we + + align:start position:0% +we have this net export function and we + + + align:start position:0% +we have this net export function and we +have more parameter we have y star is + + align:start position:0% +have more parameter we have y star is + + + align:start position:0% +have more parameter we have y star is +star and things like that and then we + + align:start position:0% +star and things like that and then we + + + align:start position:0% +star and things like that and then we +have the uip there and then then we did + + align:start position:0% +have the uip there and then then we did + + + align:start position:0% +have the uip there and then then we did +a few experiments no said suppose that + + align:start position:0% +a few experiments no said suppose that + + + align:start position:0% +a few experiments no said suppose that +now you have an expansionary monetary + + align:start position:0% +now you have an expansionary monetary + + + align:start position:0% +now you have an expansionary monetary +policy okay so an expansion in monetary + + align:start position:0% +policy okay so an expansion in monetary + + + align:start position:0% +policy okay so an expansion in monetary +policy as before with a slightly + + align:start position:0% +policy as before with a slightly + + + align:start position:0% +policy as before with a slightly +different slopes and so on because of + + align:start position:0% +different slopes and so on because of + + + align:start position:0% +different slopes and so on because of +the net export function will lower + + align:start position:0% +the net export function will lower + + + align:start position:0% +the net export function will lower +equilibrium output and it will lower it + + align:start position:0% +equilibrium output and it will lower it + + + align:start position:0% +equilibrium output and it will lower it +for two reasons as I said before will + + align:start position:0% +for two reasons as I said before will + + + align:start position:0% +for two reasons as I said before will +lower it because investment will decline + + align:start position:0% +lower it because investment will decline + + + align:start position:0% +lower it because investment will decline +but also because higher interest rate + + align:start position:0% +but also because higher interest rate + + + align:start position:0% +but also because higher interest rate +means an appreciation of the exchange + + align:start position:0% +means an appreciation of the exchange + + + align:start position:0% +means an appreciation of the exchange +rate + + align:start position:0% +rate + + + align:start position:0% +rate +today because you have to expect a + + align:start position:0% +today because you have to expect a + + + align:start position:0% +today because you have to expect a +depreciation now in the next period and + + align:start position:0% +depreciation now in the next period and + + + align:start position:0% +depreciation now in the next period and +and that that means also less net + + align:start position:0% +and that that means also less net + + + align:start position:0% +and that that means also less net +exports okay so interest rate is + + align:start position:0% +exports okay so interest rate is + + + align:start position:0% +exports okay so interest rate is +contractionary for for two different + + align:start position:0% +contractionary for for two different + + + align:start position:0% +contractionary for for two different +reasons here is that clear + + align:start position:0% +reasons here is that clear + + + align:start position:0% +reasons here is that clear +yeah raise interest + + align:start position:0% + + + + align:start position:0% + +rate raise interest rate will lower + + align:start position:0% +rate raise interest rate will lower + + + align:start position:0% +rate raise interest rate will lower +aggregate demand for the standard reason + + align:start position:0% +aggregate demand for the standard reason + + + align:start position:0% +aggregate demand for the standard reason +but on top of that we're going to get an + + align:start position:0% +but on top of that we're going to get an + + + align:start position:0% +but on top of that we're going to get an +appreciation of the exchange rate which + + align:start position:0% +appreciation of the exchange rate which + + + align:start position:0% +appreciation of the exchange rate which +also reduces net exports + + align:start position:0% +also reduces net exports + + + align:start position:0% +also reduces net exports +okay what about an increase in go + + align:start position:0% +okay what about an increase in go + + + align:start position:0% +okay what about an increase in go +expenditure well H it's the same as + + align:start position:0% +expenditure well H it's the same as + + + align:start position:0% +expenditure well H it's the same as +before and nothing changes relative to + + align:start position:0% +before and nothing changes relative to + + + align:start position:0% +before and nothing changes relative to +before except for the fact that we have + + align:start position:0% +before except for the fact that we have + + + align:start position:0% +before except for the fact that we have +a lower multiplier but it's still the + + align:start position:0% +a lower multiplier but it's still the + + + align:start position:0% +a lower multiplier but it's still the +case that is expansionary but it doesn't + + align:start position:0% +case that is expansionary but it doesn't + + + align:start position:0% +case that is expansionary but it doesn't +affect the interest rate it doesn't + + align:start position:0% +affect the interest rate it doesn't + + + align:start position:0% +affect the interest rate it doesn't +affect the exchange rate or anything + + align:start position:0% +affect the exchange rate or anything + + + align:start position:0% +affect the exchange rate or anything +like that again it's less expansionary + + align:start position:0% +like that again it's less expansionary + + + align:start position:0% +like that again it's less expansionary +than in closed economy because part of + + align:start position:0% +than in closed economy because part of + + + align:start position:0% +than in closed economy because part of +that energy will go to + + align:start position:0% + + + + align:start position:0% + +inputs then I went to this diagram and + + align:start position:0% +inputs then I went to this diagram and + + + align:start position:0% +inputs then I went to this diagram and +and I play with this uh diagram here I + + align:start position:0% +and I play with this uh diagram here I + + + align:start position:0% +and I play with this uh diagram here I +said well suppose that the expected + + align:start position:0% +said well suppose that the expected + + + align:start position:0% +said well suppose that the expected +exchanger goes up then what which curves + + align:start position:0% +exchanger goes up then what which curves + + + align:start position:0% +exchanger goes up then what which curves +change and the first one that changes is + + align:start position:0% +change and the first one that changes is + + + align:start position:0% +change and the first one that changes is +this one no this one moves to the right + + align:start position:0% +this one no this one moves to the right + + + align:start position:0% +this one no this one moves to the right +so you get an appreciation today and + + align:start position:0% +so you get an appreciation today and + + + align:start position:0% +so you get an appreciation today and +that also means that this curve here the + + align:start position:0% +that also means that this curve here the + + + align:start position:0% +that also means that this curve here the +yes will shift to the left okay if the + + align:start position:0% +yes will shift to the left okay if the + + + align:start position:0% +yes will shift to the left okay if the +spected exchanger goes up and you don't + + align:start position:0% +spected exchanger goes up and you don't + + + align:start position:0% +spected exchanger goes up and you don't +change monetary policy that means + + align:start position:0% +change monetary policy that means + + + align:start position:0% +change monetary policy that means +interest rate will go + + align:start position:0% +interest rate will go + + + align:start position:0% +interest rate will go +up sorry and you don't change monetary + + align:start position:0% +up sorry and you don't change monetary + + + align:start position:0% +up sorry and you don't change monetary +policy that means the current exchanger + + align:start position:0% +policy that means the current exchanger + + + align:start position:0% +policy that means the current exchanger +will appreciate that will reduce net + + align:start position:0% +will appreciate that will reduce net + + + align:start position:0% +will appreciate that will reduce net +export and and that's a shift in this + + align:start position:0% +export and and that's a shift in this + + + align:start position:0% +export and and that's a shift in this +space as a shift in the yes to the left + + align:start position:0% +space as a shift in the yes to the left + + + align:start position:0% +space as a shift in the yes to the left +okay this is a parameter these two + + align:start position:0% +okay this is a parameter these two + + + align:start position:0% +okay this is a parameter these two +things are parameters now in the ls + + align:start position:0% +things are parameters now in the ls + + + align:start position:0% +things are parameters now in the ls +diagram okay what about for an output uh + + align:start position:0% +diagram okay what about for an output uh + + + align:start position:0% +diagram okay what about for an output uh +going down well that doesn't affect the + + align:start position:0% +going down well that doesn't affect the + + + align:start position:0% +going down well that doesn't affect the +uip condition but it does affect net + + align:start position:0% +uip condition but it does affect net + + + align:start position:0% +uip condition but it does affect net +export so that moves I to the left okay + + align:start position:0% +export so that moves I to the left okay + + + align:start position:0% +export so that moves I to the left okay +and the last thing we did was an + + align:start position:0% +and the last thing we did was an + + + align:start position:0% +and the last thing we did was an +increase in in in isar and an increase + + align:start position:0% +increase in in in isar and an increase + + + align:start position:0% +increase in in in isar and an increase +in isar what does is know is that at the + + align:start position:0% +in isar what does is know is that at the + + + align:start position:0% +in isar what does is know is that at the +same interest rate then you know that + + align:start position:0% +same interest rate then you know that + + + align:start position:0% +same interest rate then you know that +you need a depreciation of the currency + + align:start position:0% +you need a depreciation of the currency + + + align:start position:0% +you need a depreciation of the currency +today because that will lead to an + + align:start position:0% +today because that will lead to an + + + align:start position:0% +today because that will lead to an +apprec expected appreciation so that + + align:start position:0% +apprec expected appreciation so that + + + align:start position:0% +apprec expected appreciation so that +means that this uip PE curve moves to + + align:start position:0% +means that this uip PE curve moves to + + + align:start position:0% +means that this uip PE curve moves to +the left and the is curve + + align:start position:0% +the left and the is curve + + + align:start position:0% +the left and the is curve +moves to the right that's an increase in + + align:start position:0% +moves to the right that's an increase in + + + align:start position:0% +moves to the right that's an increase in +the interest rate taken as given for an + + align:start position:0% +the interest rate taken as given for an + + + align:start position:0% +the interest rate taken as given for an +output okay if for an output also + + align:start position:0% +output okay if for an output also + + + align:start position:0% +output okay if for an output also +changes then you have to look at the + + align:start position:0% +changes then you have to look at the + + + align:start position:0% +changes then you have to look at the +combination of the two things okay but + + align:start position:0% +combination of the two things okay but + + + align:start position:0% +combination of the two things okay but +um but taking for an output as given + + align:start position:0% +um but taking for an output as given + + + align:start position:0% +um but taking for an output as given +then this Curve will shift to the left + + align:start position:0% +then this Curve will shift to the left + + + align:start position:0% +then this Curve will shift to the left +and that will move the to the right + + align:start position:0% +and that will move the to the right + + + align:start position:0% +and that will move the to the right +because the exchanger will + + align:start position:0% + + + + align:start position:0% + +depreciate you said sometimes countries + + align:start position:0% +depreciate you said sometimes countries + + + align:start position:0% +depreciate you said sometimes countries +choose to fix exchange rates and when + + align:start position:0% +choose to fix exchange rates and when + + + align:start position:0% +choose to fix exchange rates and when +you fix an exchange rate well and if + + align:start position:0% +you fix an exchange rate well and if + + + align:start position:0% +you fix an exchange rate well and if +it's credible exchange rate then the + + align:start position:0% +it's credible exchange rate then the + + + align:start position:0% +it's credible exchange rate then the +spected exchange rate equal to the + + align:start position:0% +spected exchange rate equal to the + + + align:start position:0% +spected exchange rate equal to the +actual exchange rate equal to some + + align:start position:0% +actual exchange rate equal to some + + + align:start position:0% +actual exchange rate equal to some +constant then that implies immediately + + align:start position:0% +constant then that implies immediately + + + align:start position:0% +constant then that implies immediately +that the domestic interest rate has to + + align:start position:0% +that the domestic interest rate has to + + + align:start position:0% +that the domestic interest rate has to +be equal to International interest rate + + align:start position:0% +be equal to International interest rate + + + align:start position:0% +be equal to International interest rate +okay so that if you fix your exchange + + align:start position:0% +okay so that if you fix your exchange + + + align:start position:0% +okay so that if you fix your exchange +rate to someone else then you give up + + align:start position:0% +rate to someone else then you give up + + + align:start position:0% +rate to someone else then you give up +your monetary policy the monetary policy + + align:start position:0% +your monetary policy the monetary policy + + + align:start position:0% +your monetary policy the monetary policy +is run by a different country + + align:start position:0% + + + + align:start position:0% + +okay okay good okay so that's a very + + align:start position:0% +okay okay good okay so that's a very + + + align:start position:0% +okay okay good okay so that's a very +important lecture play with it please + + align:start position:0% +important lecture play with it please + + + align:start position:0% +important lecture play with it please +well we then we look more carefully at + + align:start position:0% +well we then we look more carefully at + + + align:start position:0% +well we then we look more carefully at +at at + + align:start position:0% +at at + + + align:start position:0% +at at +uh at different exchanger + + align:start position:0% +uh at different exchanger + + + align:start position:0% +uh at different exchanger +regimes ER and and the effectiveness of + + align:start position:0% +regimes ER and and the effectiveness of + + + align:start position:0% +regimes ER and and the effectiveness of +policy within each of this regime the + + align:start position:0% +policy within each of this regime the + + + align:start position:0% +policy within each of this regime the +flexible exchange rate system which is + + align:start position:0% +flexible exchange rate system which is + + + align:start position:0% +flexible exchange rate system which is +the one we were discussing before H you + + align:start position:0% +the one we were discussing before H you + + + align:start position:0% +the one we were discussing before H you +get sort of you know if a country is in + + align:start position:0% +get sort of you know if a country is in + + + align:start position:0% +get sort of you know if a country is in +a recession you can use fiscal policy I + + align:start position:0% +a recession you can use fiscal policy I + + + align:start position:0% +a recession you can use fiscal policy I +showed you that before it works well ER + + align:start position:0% +showed you that before it works well ER + + + align:start position:0% +showed you that before it works well ER +and you can also use expansionary + + align:start position:0% +and you can also use expansionary + + + align:start position:0% +and you can also use expansionary +monetary policy which will be very + + align:start position:0% +monetary policy which will be very + + + align:start position:0% +monetary policy which will be very +successful for two reasons one the + + align:start position:0% +successful for two reasons one the + + + align:start position:0% +successful for two reasons one the +traditional one but the second reason is + + align:start position:0% +traditional one but the second reason is + + + align:start position:0% +traditional one but the second reason is +that it will depreciate your currency + + align:start position:0% +that it will depreciate your currency + + + align:start position:0% +that it will depreciate your currency +okay good now then we say suppose that + + align:start position:0% +okay good now then we say suppose that + + + align:start position:0% +okay good now then we say suppose that +you have a country that that is also in + + align:start position:0% +you have a country that that is also in + + + align:start position:0% +you have a country that that is also in +a recession but you have a a fixed + + align:start position:0% +a recession but you have a a fixed + + + align:start position:0% +a recession but you have a a fixed +exchange rate well then you still can + + align:start position:0% +exchange rate well then you still can + + + align:start position:0% +exchange rate well then you still can +use fiscal policy there's nothing + + align:start position:0% +use fiscal policy there's nothing + + + align:start position:0% +use fiscal policy there's nothing +against that but but you cannot use the + + align:start position:0% +against that but but you cannot use the + + + align:start position:0% +against that but but you cannot use the +expansion in monetary policy okay so + + align:start position:0% +expansion in monetary policy okay so + + + align:start position:0% +expansion in monetary policy okay so +that's a limitation of fixed exchang + + align:start position:0% +that's a limitation of fixed exchang + + + align:start position:0% +that's a limitation of fixed exchang +that you lose an important + + align:start position:0% + + + + align:start position:0% + +tool another problem that can arise with + + align:start position:0% +tool another problem that can arise with + + + align:start position:0% +tool another problem that can arise with +fix fixable exch fixed exchange rates is + + align:start position:0% +fix fixable exch fixed exchange rates is + + + align:start position:0% +fix fixable exch fixed exchange rates is +is speculative attacks on the currency + + align:start position:0% +is speculative attacks on the currency + + + align:start position:0% +is speculative attacks on the currency +sometimes the peg is not credible and + + align:start position:0% +sometimes the peg is not credible and + + + align:start position:0% +sometimes the peg is not credible and +when the peg is not credible you can + + align:start position:0% +when the peg is not credible you can + + + align:start position:0% +when the peg is not credible you can +imagine that you know that suppose that + + align:start position:0% +imagine that you know that suppose that + + + align:start position:0% +imagine that you know that suppose that +people expect your currency to + + align:start position:0% + + + + align:start position:0% + +depreciate depreciate so expected + + align:start position:0% +depreciate depreciate so expected + + + align:start position:0% +depreciate depreciate so expected +exchanger goes down and and suppose that + + align:start position:0% +exchanger goes down and and suppose that + + + align:start position:0% +exchanger goes down and and suppose that +you do want to keep your peg today + + align:start position:0% +you do want to keep your peg today + + + align:start position:0% +you do want to keep your peg today +that's what typically happens somebody + + align:start position:0% +that's what typically happens somebody + + + align:start position:0% +that's what typically happens somebody +speculates against your P But Central + + align:start position:0% +speculates against your P But Central + + + align:start position:0% +speculates against your P But Central +Bank resist that for a while but the + + align:start position:0% +Bank resist that for a while but the + + + align:start position:0% +Bank resist that for a while but the +only way it can resist that short of + + align:start position:0% +only way it can resist that short of + + + align:start position:0% +only way it can resist that short of +closing the capital account and doing + + align:start position:0% +closing the capital account and doing + + + align:start position:0% +closing the capital account and doing +all sort of things there but you haven't + + align:start position:0% +all sort of things there but you haven't + + + align:start position:0% +all sort of things there but you haven't +learned about those so don't worry H the + + align:start position:0% +learned about those so don't worry H the + + + align:start position:0% +learned about those so don't worry H the +only tool you have here to defend a + + align:start position:0% +only tool you have here to defend a + + + align:start position:0% +only tool you have here to defend a +speculative attack on your currency that + + align:start position:0% +speculative attack on your currency that + + + align:start position:0% +speculative attack on your currency that +is for the exchange not to depreciate + + align:start position:0% +is for the exchange not to depreciate + + + align:start position:0% +is for the exchange not to depreciate +today is by raising interest rate so the + + align:start position:0% +today is by raising interest rate so the + + + align:start position:0% +today is by raising interest rate so the +defense of an exchange rate causes a + + align:start position:0% +defense of an exchange rate causes a + + + align:start position:0% +defense of an exchange rate causes a +recession at + + align:start position:0% +recession at + + + align:start position:0% +recession at +home that's another problem that + + align:start position:0% +home that's another problem that + + + align:start position:0% +home that's another problem that +flexible exchange rate + + align:start position:0% +flexible exchange rate + + + align:start position:0% +flexible exchange rate +have and and there are sort of the deal + + align:start position:0% +have and and there are sort of the deal + + + align:start position:0% +have and and there are sort of the deal +seems pretty obvious that you don't want + + align:start position:0% +seems pretty obvious that you don't want + + + align:start position:0% +seems pretty obvious that you don't want +to have a fixed exchange rate and I said + + align:start position:0% +to have a fixed exchange rate and I said + + + align:start position:0% +to have a fixed exchange rate and I said +well be careful because flexible + + align:start position:0% +well be careful because flexible + + + align:start position:0% +well be careful because flexible +exchange rate are also not a panasa you + + align:start position:0% +exchange rate are also not a panasa you + + + align:start position:0% +exchange rate are also not a panasa you +may get lots of volatility in the + + align:start position:0% +may get lots of volatility in the + + + align:start position:0% +may get lots of volatility in the +exchange rate because the role of + + align:start position:0% +exchange rate because the role of + + + align:start position:0% +exchange rate because the role of +expectations is sort of is is very + + align:start position:0% +expectations is sort of is is very + + + align:start position:0% +expectations is sort of is is very +important um anyways this looks + + align:start position:0% +important um anyways this looks + + + align:start position:0% +important um anyways this looks +complicated but it's essentially what we + + align:start position:0% +complicated but it's essentially what we + + + align:start position:0% +complicated but it's essentially what we +did later on when we price equity and + + align:start position:0% +did later on when we price equity and + + + align:start position:0% +did later on when we price equity and +things like that we use sort of the same + + align:start position:0% +things like that we use sort of the same + + + align:start position:0% +things like that we use sort of the same +sort of iterated substitutions of things + + align:start position:0% +sort of iterated substitutions of things + + + align:start position:0% +sort of iterated substitutions of things +this was just meant to say that in a + + align:start position:0% +this was just meant to say that in a + + + align:start position:0% +this was just meant to say that in a +flexible exchange rate really and if + + align:start position:0% +flexible exchange rate really and if + + + align:start position:0% +flexible exchange rate really and if +once you endogenize Spector exchange you + + align:start position:0% +once you endogenize Spector exchange you + + + align:start position:0% +once you endogenize Spector exchange you +don't take it as a constant it gets to + + align:start position:0% +don't take it as a constant it gets to + + + align:start position:0% +don't take it as a constant it gets to +be very complicated because effectively + + align:start position:0% +be very complicated because effectively + + + align:start position:0% +be very complicated because effectively +The Exchange is spin down by the + + align:start position:0% +The Exchange is spin down by the + + + align:start position:0% +The Exchange is spin down by the +expectations of infinite Horizon of + + align:start position:0% +expectations of infinite Horizon of + + + align:start position:0% +expectations of infinite Horizon of +interest rate at home and abroad so so + + align:start position:0% +interest rate at home and abroad so so + + + align:start position:0% +interest rate at home and abroad so so +there's lots of space for creativity and + + align:start position:0% +there's lots of space for creativity and + + + align:start position:0% +there's lots of space for creativity and +moving things around and that's the + + align:start position:0% +moving things around and that's the + + + align:start position:0% +moving things around and that's the +reason exchanges can be very + + align:start position:0% + + + + align:start position:0% + +volatile okay good so anyway so all that + + align:start position:0% +volatile okay good so anyway so all that + + + align:start position:0% +volatile okay good so anyway so all that +that was it for ER Mandel flaming plus + + align:start position:0% +that was it for ER Mandel flaming plus + + + align:start position:0% +that was it for ER Mandel flaming plus +okay any question about that because now + + align:start position:0% +okay any question about that because now + + + align:start position:0% +okay any question about that because now +I'm going to move to the next part okay + + align:start position:0% +I'm going to move to the next part okay + + + align:start position:0% +I'm going to move to the next part okay +so then then uh The Next Step uh was to + + align:start position:0% +so then then uh The Next Step uh was to + + + align:start position:0% +so then then uh The Next Step uh was to +look at the asset prices really and or + + align:start position:0% +look at the asset prices really and or + + + align:start position:0% +look at the asset prices really and or +valuations of Assets in general that + + align:start position:0% +valuations of Assets in general that + + + align:start position:0% +valuations of Assets in general that +that have cash flows in the future or or + + align:start position:0% +that have cash flows in the future or or + + + align:start position:0% +that have cash flows in the future or or +or and exchange it's a little bit like + + align:start position:0% +or and exchange it's a little bit like + + + align:start position:0% +or and exchange it's a little bit like +that by the way but we talk a lot about + + align:start position:0% +that by the way but we talk a lot about + + + align:start position:0% +that by the way but we talk a lot about +current + + align:start position:0% +current + + + align:start position:0% +current +events but the key thing was this no we + + align:start position:0% +events but the key thing was this no we + + + align:start position:0% +events but the key thing was this no we +said okay you know many + + align:start position:0% +said okay you know many + + + align:start position:0% +said okay you know many +things ER many Financial or real assets + + align:start position:0% +things ER many Financial or real assets + + + align:start position:0% +things ER many Financial or real assets +actually or even your human wealth we + + align:start position:0% +actually or even your human wealth we + + + align:start position:0% +actually or even your human wealth we +discuss later on + + align:start position:0% +discuss later on + + + align:start position:0% +discuss later on +you know you you you you you you are + + align:start position:0% +you know you you you you you you are + + + align:start position:0% +you know you you you you you you are +receiving some income today but you're + + align:start position:0% +receiving some income today but you're + + + align:start position:0% +receiving some income today but you're +also expecting to receive income in the + + align:start position:0% +also expecting to receive income in the + + + align:start position:0% +also expecting to receive income in the +future and this part was about how do we + + align:start position:0% +future and this part was about how do we + + + align:start position:0% +future and this part was about how do we +value those things that we receive in + + align:start position:0% +value those things that we receive in + + + align:start position:0% +value those things that we receive in +the future those cash flows that come in + + align:start position:0% +the future those cash flows that come in + + + align:start position:0% +the future those cash flows that come in +the future and so we developed this + + align:start position:0% +the future and so we developed this + + + align:start position:0% +the future and so we developed this +concept + + align:start position:0% +concept + + + align:start position:0% +concept +of expected present discounted value and + + align:start position:0% +of expected present discounted value and + + + align:start position:0% +of expected present discounted value and +we said well very natural way of + + align:start position:0% +we said well very natural way of + + + align:start position:0% +we said well very natural way of +bringing dollars receiving the future to + + align:start position:0% +bringing dollars receiving the future to + + + align:start position:0% +bringing dollars receiving the future to +the present is to discount them by the + + align:start position:0% +the present is to discount them by the + + + align:start position:0% +the present is to discount them by the +interest rate between now and then okay + + align:start position:0% +interest rate between now and then okay + + + align:start position:0% +interest rate between now and then okay +and and the reason the logic behind that + + align:start position:0% +and and the reason the logic behind that + + + align:start position:0% +and and the reason the logic behind that +is because if you give me a dollar today + + align:start position:0% +is because if you give me a dollar today + + + align:start position:0% +is because if you give me a dollar today +I can do a lot more than if you give me + + align:start position:0% +I can do a lot more than if you give me + + + align:start position:0% +I can do a lot more than if you give me +a dollar five years from now because I + + align:start position:0% +a dollar five years from now because I + + + align:start position:0% +a dollar five years from now because I +can invest the dollar today and earn the + + align:start position:0% +can invest the dollar today and earn the + + + align:start position:0% +can invest the dollar today and earn the +interest rate return up to five years + + align:start position:0% +interest rate return up to five years + + + align:start position:0% +interest rate return up to five years +from now so a dollar today is worth a + + align:start position:0% +from now so a dollar today is worth a + + + align:start position:0% +from now so a dollar today is worth a +lot more than five years a dollar five + + align:start position:0% +lot more than five years a dollar five + + + align:start position:0% +lot more than five years a dollar five +years from now therefore a dollar five + + align:start position:0% +years from now therefore a dollar five + + + align:start position:0% +years from now therefore a dollar five +years from now is worth a lot less than + + align:start position:0% +years from now is worth a lot less than + + + align:start position:0% +years from now is worth a lot less than +a dollar today how much less one over + + align:start position:0% +a dollar today how much less one over + + + align:start position:0% +a dollar today how much less one over +one plus the interest rate over that + + align:start position:0% +one plus the interest rate over that + + + align:start position:0% +one plus the interest rate over that +period which is + + align:start position:0% +period which is + + + align:start position:0% +period which is +okay so that's what we did then I show + + align:start position:0% +okay so that's what we did then I show + + + align:start position:0% +okay so that's what we did then I show +you sort of a general a general cash + + align:start position:0% +you sort of a general a general cash + + + align:start position:0% +you sort of a general a general cash +flow this is an asset that gives a cash + + align:start position:0% +flow this is an asset that gives a cash + + + align:start position:0% +flow this is an asset that gives a cash +flow ZT at the beginning of this period + + align:start position:0% +flow ZT at the beginning of this period + + + align:start position:0% +flow ZT at the beginning of this period +ZT plus one at the beginning of the next + + align:start position:0% +ZT plus one at the beginning of the next + + + align:start position:0% +ZT plus one at the beginning of the next +one or at the end of this one something + + align:start position:0% +one or at the end of this one something + + + align:start position:0% +one or at the end of this one something +like that well this one you don't need + + align:start position:0% +like that well this one you don't need + + + align:start position:0% +like that well this one you don't need +to Discount that one you do need to + + align:start position:0% +to Discount that one you do need to + + + align:start position:0% +to Discount that one you do need to +Discount because you're not receiving it + + align:start position:0% +Discount because you're not receiving it + + + align:start position:0% +Discount because you're not receiving it +now you're receiving it a year from now + + align:start position:0% +now you're receiving it a year from now + + + align:start position:0% +now you're receiving it a year from now +this when you need it's two years from + + align:start position:0% +this when you need it's two years from + + + align:start position:0% +this when you need it's two years from +now you need to discount it more because + + align:start position:0% +now you need to discount it more because + + + align:start position:0% +now you need to discount it more because +you know it's two years that you could + + align:start position:0% +you know it's two years that you could + + + align:start position:0% +you know it's two years that you could +be earning interest rate and so on so + + align:start position:0% +be earning interest rate and so on so + + + align:start position:0% +be earning interest rate and so on so +forth okay this formula you need to + + align:start position:0% + + + + align:start position:0% + +understand uh and I said well that's if + + align:start position:0% +understand uh and I said well that's if + + + align:start position:0% +understand uh and I said well that's if +you know the future if you don't know + + align:start position:0% +you know the future if you don't know + + + align:start position:0% +you know the future if you don't know +the future then you just replace the + + align:start position:0% +the future then you just replace the + + + align:start position:0% +the future then you just replace the +things you don't know for the respected + + align:start position:0% +things you don't know for the respected + + + align:start position:0% +things you don't know for the respected +value that's what and that's the + + align:start position:0% +value that's what and that's the + + + align:start position:0% +value that's what and that's the +approximation in real I mean if you were + + align:start position:0% +approximation in real I mean if you were + + + align:start position:0% +approximation in real I mean if you were +to do this formally it's a little more + + align:start position:0% +to do this formally it's a little more + + + align:start position:0% +to do this formally it's a little more +complicated but for this course that's + + align:start position:0% +complicated but for this course that's + + + align:start position:0% +complicated but for this course that's +all that you do + + align:start position:0% +all that you do + + + align:start position:0% +all that you do +okay and then I look at some particular + + align:start position:0% +okay and then I look at some particular + + + align:start position:0% +okay and then I look at some particular +cases this this is a case the same case + + align:start position:0% +cases this this is a case the same case + + + align:start position:0% +cases this this is a case the same case +but in one in which the interest rate is + + align:start position:0% +but in one in which the interest rate is + + + align:start position:0% +but in one in which the interest rate is +constant suppose that you expect the + + align:start position:0% +constant suppose that you expect the + + + align:start position:0% +constant suppose that you expect the +interest rate to be constant then is a + + align:start position:0% +interest rate to be constant then is a + + + align:start position:0% +interest rate to be constant then is a +little simpler expression because rather + + align:start position:0% +little simpler expression because rather + + + align:start position:0% +little simpler expression because rather +than getting these products of one plus + + align:start position:0% +than getting these products of one plus + + + align:start position:0% +than getting these products of one plus +one the interest rates at different + + align:start position:0% +one the interest rates at different + + + align:start position:0% +one the interest rates at different +times H you get just powers of one plus + + align:start position:0% +times H you get just powers of one plus + + + align:start position:0% +times H you get just powers of one plus +I then another one that is simpler + + align:start position:0% +I then another one that is simpler + + + align:start position:0% +I then another one that is simpler +obviously is one in which all these + + align:start position:0% +obviously is one in which all these + + + align:start position:0% +obviously is one in which all these +expected payments are constant and so on + + align:start position:0% +expected payments are constant and so on + + + align:start position:0% +expected payments are constant and so on +and then even simpler if you spec if the + + align:start position:0% +and then even simpler if you spec if the + + + align:start position:0% +and then even simpler if you spec if the +con if the interest rate is constant and + + align:start position:0% +con if the interest rate is constant and + + + align:start position:0% +con if the interest rate is constant and +the payment is constant H you get some + + align:start position:0% +the payment is constant H you get some + + + align:start position:0% +the payment is constant H you get some +simple formulas like that simpler + + align:start position:0% +simple formulas like that simpler + + + align:start position:0% +simple formulas like that simpler +formulas and then cases in which asset + + align:start position:0% +formulas and then cases in which asset + + + align:start position:0% +formulas and then cases in which asset +lives forever of that kind then that's + + align:start position:0% +lives forever of that kind then that's + + + align:start position:0% +lives forever of that kind then that's +value if you don't pay for if you don't + + align:start position:0% +value if you don't pay for if you don't + + + align:start position:0% +value if you don't pay for if you don't +receive the the First Cash Flow now but + + align:start position:0% +receive the the First Cash Flow now but + + + align:start position:0% +receive the the First Cash Flow now but +you receive it at the beginning of next + + align:start position:0% +you receive it at the beginning of next + + + align:start position:0% +you receive it at the beginning of next +year or at the end of this one then it + + align:start position:0% +year or at the end of this one then it + + + align:start position:0% +year or at the end of this one then it +gets even simpler like that and I you're + + align:start position:0% +gets even simpler like that and I you're + + + align:start position:0% +gets even simpler like that and I you're +going to get a question of this kind + + align:start position:0% +going to get a question of this kind + + + align:start position:0% +going to get a question of this kind +okay and which you're going to be asked + + align:start position:0% +okay and which you're going to be asked + + + align:start position:0% +okay and which you're going to be asked +to compare two different assets that + + align:start position:0% +to compare two different assets that + + + align:start position:0% +to compare two different assets that +have a different profiles of cash flows + + align:start position:0% +have a different profiles of cash flows + + + align:start position:0% +have a different profiles of cash flows +and you're going to have to compare + + align:start position:0% +and you're going to have to compare + + + align:start position:0% +and you're going to have to compare +between those two okay then we talk + + align:start position:0% +between those two okay then we talk + + + align:start position:0% +between those two okay then we talk +about bonds and bond yields and + + align:start position:0% +about bonds and bond yields and + + + align:start position:0% +about bonds and bond yields and +essentially we use expected present + + align:start position:0% +essentially we use expected present + + + align:start position:0% +essentially we use expected present +discounted value formula just for bonds + + align:start position:0% +discounted value formula just for bonds + + + align:start position:0% +discounted value formula just for bonds +and bonds bonds have a very particular + + align:start position:0% +and bonds bonds have a very particular + + + align:start position:0% +and bonds bonds have a very particular +form profile of payment typically some + + align:start position:0% +form profile of payment typically some + + + align:start position:0% +form profile of payment typically some +coupons and some final payment which is + + align:start position:0% +coupons and some final payment which is + + + align:start position:0% +coupons and some final payment which is +we call it the face value of the bond or + + align:start position:0% +we call it the face value of the bond or + + + align:start position:0% +we call it the face value of the bond or +something like that and we said a very + + align:start position:0% +something like that and we said a very + + + align:start position:0% +something like that and we said a very +important Concept in bonds is + + align:start position:0% +important Concept in bonds is + + + align:start position:0% +important Concept in bonds is +maturity maturity is the date or the + + align:start position:0% +maturity maturity is the date or the + + + align:start position:0% +maturity maturity is the date or the +number of years till the last payment on + + align:start position:0% +number of years till the last payment on + + + align:start position:0% +number of years till the last payment on +that Bond okay doesn't matter whether + + align:start position:0% +that Bond okay doesn't matter whether + + + align:start position:0% +that Bond okay doesn't matter whether +you receive lots of little coupons along + + align:start position:0% +you receive lots of little coupons along + + + align:start position:0% +you receive lots of little coupons along +the way and one final payment whether + + align:start position:0% +the way and one final payment whether + + + align:start position:0% +the way and one final payment whether +you receive no payment what whatever + + align:start position:0% +you receive no payment what whatever + + + align:start position:0% +you receive no payment what whatever +until the last date that doesn't matter + + align:start position:0% +until the last date that doesn't matter + + + align:start position:0% +until the last date that doesn't matter +the maturity of a bond is the date the + + align:start position:0% +the maturity of a bond is the date the + + + align:start position:0% +the maturity of a bond is the date the +number of years till the last time you + + align:start position:0% +number of years till the last time you + + + align:start position:0% +number of years till the last time you +your last payment + + align:start position:0% +your last payment + + + align:start position:0% +your last payment +okay so we give some examples there a + + align:start position:0% +okay so we give some examples there a + + + align:start position:0% +okay so we give some examples there a +bond that pays nothing now but pays 101 + + align:start position:0% +bond that pays nothing now but pays 101 + + + align:start position:0% +bond that pays nothing now but pays 101 +year from now ER has a has a price is a + + align:start position:0% +year from now ER has a has a price is a + + + align:start position:0% +year from now ER has a has a price is a +pres is discounted value of 100 no one + + align:start position:0% +pres is discounted value of 100 no one + + + align:start position:0% +pres is discounted value of 100 no one +year divided by one plus the one year + + align:start position:0% +year divided by one plus the one year + + + align:start position:0% +year divided by one plus the one year +interest rate at time + + align:start position:0% +interest rate at time + + + align:start position:0% +interest rate at time +T um a bond that pays nothing up to two + + align:start position:0% +T um a bond that pays nothing up to two + + + align:start position:0% +T um a bond that pays nothing up to two +years and then in the second at the end + + align:start position:0% +years and then in the second at the end + + + align:start position:0% +years and then in the second at the end +then after two years pays $100 then + + align:start position:0% +then after two years pays $100 then + + + align:start position:0% +then after two years pays $100 then +that's a value the price of that bond + + align:start position:0% +that's a value the price of that bond + + + align:start position:0% +that's a value the price of that bond +which is 100 discounted by that + + align:start position:0% +which is 100 discounted by that + + + align:start position:0% +which is 100 discounted by that +okay H then we look at Arbitrage which + + align:start position:0% +okay H then we look at Arbitrage which + + + align:start position:0% +okay H then we look at Arbitrage which +is says suppose that you you hold a bond + + align:start position:0% +is says suppose that you you hold a bond + + + align:start position:0% +is says suppose that you you hold a bond +that that you're considering + + align:start position:0% +that that you're considering + + + align:start position:0% +that that you're considering +investing your money for one year but + + align:start position:0% +investing your money for one year but + + + align:start position:0% +investing your money for one year but +you have two options one is to buy a + + align:start position:0% +you have two options one is to buy a + + + align:start position:0% +you have two options one is to buy a +one-year Bond the alternative is to buy + + align:start position:0% +one-year Bond the alternative is to buy + + + align:start position:0% +one-year Bond the alternative is to buy +a two-year Bond now and sell it at the + + align:start position:0% +a two-year Bond now and sell it at the + + + align:start position:0% +a two-year Bond now and sell it at the +end of the year those two strategies + + align:start position:0% +end of the year those two strategies + + + align:start position:0% +end of the year those two strategies +should would give you more or less the + + align:start position:0% +should would give you more or less the + + + align:start position:0% +should would give you more or less the +same return H well you know if you if + + align:start position:0% +same return H well you know if you if + + + align:start position:0% +same return H well you know if you if +you buy a one-year Bond you're going to + + align:start position:0% +you buy a one-year Bond you're going to + + + align:start position:0% +you buy a one-year Bond you're going to +get 1 plus i1t at the end of the year if + + align:start position:0% +get 1 plus i1t at the end of the year if + + + align:start position:0% +get 1 plus i1t at the end of the year if +you go through the two-year Bond + + align:start position:0% +you go through the two-year Bond + + + align:start position:0% +you go through the two-year Bond +strategy then H you're going to pay this + + align:start position:0% +strategy then H you're going to pay this + + + align:start position:0% +strategy then H you're going to pay this +today but you're going to you're going + + align:start position:0% +today but you're going to you're going + + + align:start position:0% +today but you're going to you're going +to H ER rece expect you expect to + + align:start position:0% +to H ER rece expect you expect to + + + align:start position:0% +to H ER rece expect you expect to +receive the price of a oneyear bond one + + align:start position:0% +receive the price of a oneyear bond one + + + align:start position:0% +receive the price of a oneyear bond one +year from now and we said these two + + align:start position:0% +year from now and we said these two + + + align:start position:0% +year from now and we said these two +things have to be equal more or less + + align:start position:0% +things have to be equal more or less + + + align:start position:0% +things have to be equal more or less +equal I mean again we're not adding risk + + align:start position:0% +equal I mean again we're not adding risk + + + align:start position:0% +equal I mean again we're not adding risk +to these things H if there's no risk + + align:start position:0% +to these things H if there's no risk + + + align:start position:0% +to these things H if there's no risk +consideration of agents at risk neutral + + align:start position:0% +consideration of agents at risk neutral + + + align:start position:0% +consideration of agents at risk neutral +then these two things have to be equal H + + align:start position:0% +then these two things have to be equal H + + + align:start position:0% +then these two things have to be equal H +that allows you to solve for the price + + align:start position:0% +that allows you to solve for the price + + + align:start position:0% +that allows you to solve for the price +of a two-year Bond as expected price of + + align:start position:0% +of a two-year Bond as expected price of + + + align:start position:0% +of a two-year Bond as expected price of +a oneyear bond one year from now divided + + align:start position:0% +a oneyear bond one year from now divided + + + align:start position:0% +a oneyear bond one year from now divided +by one plus the interest rate but the + + align:start position:0% +by one plus the interest rate but the + + + align:start position:0% +by one plus the interest rate but the +expected price of one year bond one year + + align:start position:0% +expected price of one year bond one year + + + align:start position:0% +expected price of one year bond one year +from now is going to be like a oneyear + + align:start position:0% +from now is going to be like a oneyear + + + align:start position:0% +from now is going to be like a oneyear +bond but one year from now so it's 100 + + align:start position:0% +bond but one year from now so it's 100 + + + align:start position:0% +bond but one year from now so it's 100 +divided 1 + i1 t + 1 expected value I + + align:start position:0% +divided 1 + i1 t + 1 expected value I + + + align:start position:0% +divided 1 + i1 t + 1 expected value I +can stick that in there and I get EX the + + align:start position:0% +can stick that in there and I get EX the + + + align:start position:0% +can stick that in there and I get EX the +same expression okay so these are two + + align:start position:0% +same expression okay so these are two + + + align:start position:0% +same expression okay so these are two +different ways of pricing a + + align:start position:0% +different ways of pricing a + + + align:start position:0% +different ways of pricing a +bond or any other asset by + + align:start position:0% +bond or any other asset by + + + align:start position:0% +bond or any other asset by +actually and then we Define the yield to + + align:start position:0% +actually and then we Define the yield to + + + align:start position:0% +actually and then we Define the yield to +maturity so that's an important + + align:start position:0% +maturity so that's an important + + + align:start position:0% +maturity so that's an important +concept yield to + + align:start position:0% +concept yield to + + + align:start position:0% +concept yield to +maturity is is is is a is a rate that is + + align:start position:0% +maturity is is is is a is a rate that is + + + align:start position:0% +maturity is is is is a is a rate that is +a constant + + align:start position:0% +a constant + + + align:start position:0% +a constant +rate that gives you Thea exactly the + + align:start position:0% +rate that gives you Thea exactly the + + + align:start position:0% +rate that gives you Thea exactly the +same + + align:start position:0% +same + + + align:start position:0% +same +that gives you the current price of the + + align:start position:0% +that gives you the current price of the + + + align:start position:0% +that gives you the current price of the +bond okay so we already determined the + + align:start position:0% +bond okay so we already determined the + + + align:start position:0% +bond okay so we already determined the +the price of a two-year bond is that + + align:start position:0% +the price of a two-year bond is that + + + align:start position:0% +the price of a two-year bond is that +okay and now I'm saying well suppose + + align:start position:0% +okay and now I'm saying well suppose + + + align:start position:0% +okay and now I'm saying well suppose +that let me look for a rate that is the + + align:start position:0% +that let me look for a rate that is the + + + align:start position:0% +that let me look for a rate that is the +same in both + + align:start position:0% +same in both + + + align:start position:0% +same in both +periods that gives me the same price and + + align:start position:0% +periods that gives me the same price and + + + align:start position:0% +periods that gives me the same price and +that's that's the reason I have a + + align:start position:0% +that's that's the reason I have a + + + align:start position:0% +that's that's the reason I have a +subscript two here at time T so what is + + align:start position:0% +subscript two here at time T so what is + + + align:start position:0% +subscript two here at time T so what is +the rate that if I put a constant rate + + align:start position:0% +the rate that if I put a constant rate + + + align:start position:0% +the rate that if I put a constant rate +so I have 1 + I2 T * 1 + + + align:start position:0% +so I have 1 + I2 T * 1 + + + + align:start position:0% +so I have 1 + I2 T * 1 + +i2t gives me exactly the same price as + + align:start position:0% +i2t gives me exactly the same price as + + + align:start position:0% +i2t gives me exactly the same price as +the one we already determined okay and + + align:start position:0% +the one we already determined okay and + + + align:start position:0% +the one we already determined okay and +that's what we call the yield to + + align:start position:0% +that's what we call the yield to + + + align:start position:0% +that's what we call the yield to +maturity or the yield or or the end in + + align:start position:0% +maturity or the yield or or the end in + + + align:start position:0% +maturity or the yield or or the end in +this case would be a two-year rate if + + align:start position:0% +this case would be a two-year rate if + + + align:start position:0% +this case would be a two-year rate if +you hear what is a two-year rate is that + + align:start position:0% +you hear what is a two-year rate is that + + + align:start position:0% +you hear what is a two-year rate is that +okay H so so we know what this price is + + align:start position:0% +okay H so so we know what this price is + + + align:start position:0% +okay H so so we know what this price is +which is equal to that that's this + + align:start position:0% +which is equal to that that's this + + + align:start position:0% +which is equal to that that's this +expression there so the whole trick here + + align:start position:0% +expression there so the whole trick here + + + align:start position:0% +expression there so the whole trick here +is to find the 2-year rate at time T + + align:start position:0% +is to find the 2-year rate at time T + + + align:start position:0% +is to find the 2-year rate at time T +that that gives exactly the same value + + align:start position:0% +that that gives exactly the same value + + + align:start position:0% +that that gives exactly the same value +that means obviously since 100 is equal + + align:start position:0% +that means obviously since 100 is equal + + + align:start position:0% +that means obviously since 100 is equal +to 100 it means to find the i2t that + + align:start position:0% +to 100 it means to find the i2t that + + + align:start position:0% +to 100 it means to find the i2t that +gives you this equal to that which would + + align:start position:0% +gives you this equal to that which would + + + align:start position:0% +gives you this equal to that which would +say is approximate implies that + + align:start position:0% +say is approximate implies that + + + align:start position:0% +say is approximate implies that +approximately the twoyear rate is like + + align:start position:0% +approximately the twoyear rate is like + + + align:start position:0% +approximately the twoyear rate is like +an average of the two rate of the two + + align:start position:0% +an average of the two rate of the two + + + align:start position:0% +an average of the two rate of the two +onee rates okay but this concept you + + align:start position:0% +onee rates okay but this concept you + + + align:start position:0% +onee rates okay but this concept you +should know what it + + align:start position:0% +should know what it + + + align:start position:0% +should know what it +is I said there are two forms of risk in + + align:start position:0% +is I said there are two forms of risk in + + + align:start position:0% +is I said there are two forms of risk in +a bond there one one type of risk is the + + align:start position:0% +a bond there one one type of risk is the + + + align:start position:0% +a bond there one one type of risk is the +fall risk what if the issuer of the bond + + align:start position:0% +fall risk what if the issuer of the bond + + + align:start position:0% +fall risk what if the issuer of the bond +doesn't pay you now there's a huge issue + + align:start position:0% +doesn't pay you now there's a huge issue + + + align:start position:0% +doesn't pay you now there's a huge issue +with the US you know Deb ceiling because + + align:start position:0% +with the US you know Deb ceiling because + + + align:start position:0% +with the US you know Deb ceiling because +if they somehow they don't fix that + + align:start position:0% +if they somehow they don't fix that + + + align:start position:0% +if they somehow they don't fix that +there will be a default on some treasury + + align:start position:0% +there will be a default on some treasury + + + align:start position:0% +there will be a default on some treasury +bonds let's hope that it doesn't happen + + align:start position:0% +bonds let's hope that it doesn't happen + + + align:start position:0% +bonds let's hope that it doesn't happen +but but but that's theault risk is that + + align:start position:0% +but but but that's theault risk is that + + + align:start position:0% +but but but that's theault risk is that +whoever issued the debt at the time in + + align:start position:0% +whoever issued the debt at the time in + + + align:start position:0% +whoever issued the debt at the time in +which he should be paying you a coupon + + align:start position:0% +which he should be paying you a coupon + + + align:start position:0% +which he should be paying you a coupon +or or the principal the face value it + + align:start position:0% +or or the principal the face value it + + + align:start position:0% +or or the principal the face value it +doesn't pay you that's the fall risk + + align:start position:0% +doesn't pay you that's the fall risk + + + align:start position:0% +doesn't pay you that's the fall risk +okay and and and typically US Treasury + + align:start position:0% +okay and and and typically US Treasury + + + align:start position:0% +okay and and and typically US Treasury +bonds don't have the risk so nobody + + align:start position:0% +bonds don't have the risk so nobody + + + align:start position:0% +bonds don't have the risk so nobody +worries about that at this moment + + align:start position:0% +worries about that at this moment + + + align:start position:0% +worries about that at this moment +the default risk price in US bonds for + + align:start position:0% +the default risk price in US bonds for + + + align:start position:0% +the default risk price in US bonds for +one month bonds is higher than that of + + align:start position:0% +one month bonds is higher than that of + + + align:start position:0% +one month bonds is higher than that of +Mexico the bonds in Mexico or Brazil + + align:start position:0% +Mexico the bonds in Mexico or Brazil + + + align:start position:0% +Mexico the bonds in Mexico or Brazil +that tells you that the kind of things + + align:start position:0% +that tells you that the kind of things + + + align:start position:0% +that tells you that the kind of things +we have but in any EV so so this is a + + align:start position:0% +we have but in any EV so so this is a + + + align:start position:0% +we have but in any EV so so this is a +temporary default risk I mean nobody + + align:start position:0% +temporary default risk I mean nobody + + + align:start position:0% +temporary default risk I mean nobody +expects in the US that this will not be + + align:start position:0% +expects in the US that this will not be + + + align:start position:0% +expects in the US that this will not be +eventually repaid but you can cause a + + align:start position:0% +eventually repaid but you can cause a + + + align:start position:0% +eventually repaid but you can cause a +big + + align:start position:0% +big + + + align:start position:0% +big +mess by just ER delaying a a coupon + + align:start position:0% +mess by just ER delaying a a coupon + + + align:start position:0% +mess by just ER delaying a a coupon +payment I mean when when when these + + align:start position:0% +payment I mean when when when these + + + align:start position:0% +payment I mean when when when these +coupons are huge no + + align:start position:0% +coupons are huge no + + + align:start position:0% +coupons are huge no +and so so that's what's leading to all + + align:start position:0% +and so so that's what's leading to all + + + align:start position:0% +and so so that's what's leading to all +this concern but but in any + + align:start position:0% +this concern but but in any + + + align:start position:0% +this concern but but in any +EV that's one type of risk but we didn't + + align:start position:0% +EV that's one type of risk but we didn't + + + align:start position:0% +EV that's one type of risk but we didn't +look at that type of risk a lot the + + align:start position:0% +look at that type of risk a lot the + + + align:start position:0% +look at that type of risk a lot the +corporate bonds have a lot of that risk + + align:start position:0% +corporate bonds have a lot of that risk + + + align:start position:0% +corporate bonds have a lot of that risk +but we didn't look at that kind of risk + + align:start position:0% +but we didn't look at that kind of risk + + + align:start position:0% +but we didn't look at that kind of risk +we look at the another kind of risk + + align:start position:0% +we look at the another kind of risk + + + align:start position:0% +we look at the another kind of risk +which is price risk no if you have a one + + align:start position:0% +which is price risk no if you have a one + + + align:start position:0% +which is price risk no if you have a one +you invest in your oneyear bond there no + + align:start position:0% +you invest in your oneyear bond there no + + + align:start position:0% +you invest in your oneyear bond there no +price risk you're going to get your + + align:start position:0% +price risk you're going to get your + + + align:start position:0% +price risk you're going to get your +coupon your face value of 100 at the end + + align:start position:0% +coupon your face value of 100 at the end + + + align:start position:0% +coupon your face value of 100 at the end +of the year that's it if you go through + + align:start position:0% +of the year that's it if you go through + + + align:start position:0% +of the year that's it if you go through +a two-year strategy there's a risk there + + align:start position:0% +a two-year strategy there's a risk there + + + align:start position:0% +a two-year strategy there's a risk there +because you don't know exactly what the + + align:start position:0% +because you don't know exactly what the + + + align:start position:0% +because you don't know exactly what the +price of the two oneyear Bond will will + + align:start position:0% +price of the two oneyear Bond will will + + + align:start position:0% +price of the two oneyear Bond will will +be one year from now and there's a risk + + align:start position:0% +be one year from now and there's a risk + + + align:start position:0% +be one year from now and there's a risk +there we are not looking at what risk + + align:start position:0% +there we are not looking at what risk + + + align:start position:0% +there we are not looking at what risk +Avers cons investors do and so on but in + + align:start position:0% +Avers cons investors do and so on but in + + + align:start position:0% +Avers cons investors do and so on but in +reality there is such a risk okay and + + align:start position:0% +reality there is such a risk okay and + + + align:start position:0% +reality there is such a risk okay and +just the way we mold that is we said + + align:start position:0% +just the way we mold that is we said + + + align:start position:0% +just the way we mold that is we said +well then if I'm going to go through two + + align:start position:0% +well then if I'm going to go through two + + + align:start position:0% +well then if I'm going to go through two +years through a two-year bone route for + + align:start position:0% +years through a two-year bone route for + + + align:start position:0% +years through a two-year bone route for +a one-year investment then I don't have + + align:start position:0% +a one-year investment then I don't have + + + align:start position:0% +a one-year investment then I don't have +to H set this equal to the return I get + + align:start position:0% +to H set this equal to the return I get + + + align:start position:0% +to H set this equal to the return I get +in the sh Bond the oneyear bond I have + + align:start position:0% +in the sh Bond the oneyear bond I have + + + align:start position:0% +in the sh Bond the oneyear bond I have +to add an extra risk premium and then + + align:start position:0% +to add an extra risk premium and then + + + align:start position:0% +to add an extra risk premium and then +where right to this formula using the + + align:start position:0% +where right to this formula using the + + + align:start position:0% +where right to this formula using the +same steps we said well the one the the + + align:start position:0% +same steps we said well the one the the + + + align:start position:0% +same steps we said well the one the the +the two-year rate is really the average + + align:start position:0% +the two-year rate is really the average + + + align:start position:0% +the two-year rate is really the average +of the one expected onee rates plus a a + + align:start position:0% +of the one expected onee rates plus a a + + + align:start position:0% +of the one expected onee rates plus a a +premium and we call that actually the + + align:start position:0% +premium and we call that actually the + + + align:start position:0% +premium and we call that actually the +term + + align:start position:0% +term + + + align:start position:0% +term +premium you're more likely to face a + + align:start position:0% +premium you're more likely to face a + + + align:start position:0% +premium you're more likely to face a +question about the top of this slide and + + align:start position:0% +question about the top of this slide and + + + align:start position:0% +question about the top of this slide and +the bottom of the slide but I don't + + align:start position:0% +the bottom of the slide but I don't + + + align:start position:0% +the bottom of the slide but I don't +remember + + align:start position:0% + + + + align:start position:0% + +fully + + align:start position:0% +fully + + + align:start position:0% +fully +ER stock prices and Present Value well + + align:start position:0% +ER stock prices and Present Value well + + + align:start position:0% +ER stock prices and Present Value well +it's the same sort of idea know the only + + align:start position:0% +it's the same sort of idea know the only + + + align:start position:0% +it's the same sort of idea know the only +difference is + + align:start position:0% +difference is + + + align:start position:0% +difference is +that that that uh equities do not have + + align:start position:0% +that that that uh equities do not have + + + align:start position:0% +that that that uh equities do not have +maturity stocks do not have maturity in + + align:start position:0% +maturity stocks do not have maturity in + + + align:start position:0% +maturity stocks do not have maturity in +principle a company would last forever + + align:start position:0% +principle a company would last forever + + + align:start position:0% +principle a company would last forever +and and and so there's no there's no + + align:start position:0% +and and and so there's no there's no + + + align:start position:0% +and and and so there's no there's no +maturity and there is also the + + align:start position:0% +maturity and there is also the + + + align:start position:0% +maturity and there is also the +commitment of the coupons are a lot + + align:start position:0% +commitment of the coupons are a lot + + + align:start position:0% +commitment of the coupons are a lot +shakier in the sense that you know yeah + + align:start position:0% +shakier in the sense that you know yeah + + + align:start position:0% +shakier in the sense that you know yeah +compan is likely to give dividends they + + align:start position:0% +compan is likely to give dividends they + + + align:start position:0% +compan is likely to give dividends they +may announce a dividend policy but it's + + align:start position:0% +may announce a dividend policy but it's + + + align:start position:0% +may announce a dividend policy but it's +not a + + align:start position:0% +not a + + + align:start position:0% +not a +commitment if you know Regional Banks + + align:start position:0% +commitment if you know Regional Banks + + + align:start position:0% +commitment if you know Regional Banks +now are not giving any dividend because + + align:start position:0% +now are not giving any dividend because + + + align:start position:0% +now are not giving any dividend because +they want to preserve the capital okay + + align:start position:0% +they want to preserve the capital okay + + + align:start position:0% +they want to preserve the capital okay +they could but they're not because they + + align:start position:0% +they could but they're not because they + + + align:start position:0% +they could but they're not because they +want to build Capital just to be more + + align:start position:0% +want to build Capital just to be more + + + align:start position:0% +want to build Capital just to be more +resilient + + align:start position:0% +resilient + + + align:start position:0% +resilient +to any fly bad news okay but anyway so + + align:start position:0% +to any fly bad news okay but anyway so + + + align:start position:0% +to any fly bad news okay but anyway so +Equity that that means that you always + + align:start position:0% +Equity that that means that you always + + + align:start position:0% +Equity that that means that you always +have this future price floating around + + align:start position:0% +have this future price floating around + + + align:start position:0% +have this future price floating around +and you can keep substituting this + + align:start position:0% +and you can keep substituting this + + + align:start position:0% +and you can keep substituting this +multiple times and essentially you get + + align:start position:0% +multiple times and essentially you get + + + align:start position:0% +multiple times and essentially you get +to an expression that says look the the + + align:start position:0% +to an expression that says look the the + + + align:start position:0% +to an expression that says look the the +price of equity is really this the + + align:start position:0% +price of equity is really this the + + + align:start position:0% +price of equity is really this the +spected present discounted value of the + + align:start position:0% +spected present discounted value of the + + + align:start position:0% +spected present discounted value of the +dividends H and that includes lots of + + align:start position:0% +dividends H and that includes lots of + + + align:start position:0% +dividends H and that includes lots of +uncertainty because because you don't + + align:start position:0% +uncertainty because because you don't + + + align:start position:0% +uncertainty because because you don't +know exactly where the interest rate + + align:start position:0% +know exactly where the interest rate + + + align:start position:0% +know exactly where the interest rate +will be in that period and so on and + + align:start position:0% +will be in that period and so on and + + + align:start position:0% +will be in that period and so on and +there's always a a a remaining term out + + align:start position:0% +there's always a a a remaining term out + + + align:start position:0% +there's always a a a remaining term out +there which also causes a lot of trouble + + align:start position:0% +there which also causes a lot of trouble + + + align:start position:0% +there which also causes a lot of trouble +in practice + + align:start position:0% +in practice + + + align:start position:0% +in practice +assets equities move a lot more than + + align:start position:0% +assets equities move a lot more than + + + align:start position:0% +assets equities move a lot more than +than what you can justify with the + + align:start position:0% +than what you can justify with the + + + align:start position:0% +than what you can justify with the +Spector present value of + + align:start position:0% +Spector present value of + + + align:start position:0% +Spector present value of +dividends there's a lot of + + align:start position:0% +dividends there's a lot of + + + align:start position:0% +dividends there's a lot of +volatility ER there are bubbles and all + + align:start position:0% +volatility ER there are bubbles and all + + + align:start position:0% +volatility ER there are bubbles and all +sort of things I told you the story of + + align:start position:0% +sort of things I told you the story of + + + align:start position:0% +sort of things I told you the story of +Newton and and so on so so this formula + + align:start position:0% +Newton and and so on so so this formula + + + align:start position:0% +Newton and and so on so so this formula +for the bonds those formulas are great + + align:start position:0% +for the bonds those formulas are great + + + align:start position:0% +for the bonds those formulas are great +for Equity you're going to be pretty far + + align:start position:0% +for Equity you're going to be pretty far + + + align:start position:0% +for Equity you're going to be pretty far +off actual prices if you use this type + + align:start position:0% +off actual prices if you use this type + + + align:start position:0% +off actual prices if you use this type +of formulas still people call this the + + align:start position:0% +of formulas still people call this the + + + align:start position:0% +of formulas still people call this the +fundamental value of equity and then the + + align:start position:0% +fundamental value of equity and then the + + + align:start position:0% +fundamental value of equity and then the +rest is sort of more speculative but the + + align:start position:0% +rest is sort of more speculative but the + + + align:start position:0% +rest is sort of more speculative but the +point is that the speculative component + + align:start position:0% +point is that the speculative component + + + align:start position:0% +point is that the speculative component +moves at all is is responsible for a + + align:start position:0% +moves at all is is responsible for a + + + align:start position:0% +moves at all is is responsible for a +very large share of the volatility in + + align:start position:0% +very large share of the volatility in + + + align:start position:0% +very large share of the volatility in +asset in equity price in any event I'm + + align:start position:0% +asset in equity price in any event I'm + + + align:start position:0% +asset in equity price in any event I'm +not going to ask you about this kind of + + align:start position:0% +not going to ask you about this kind of + + + align:start position:0% +not going to ask you about this kind of +yeah for that final equation on the SL + + align:start position:0% +yeah for that final equation on the SL + + + align:start position:0% +yeah for that final equation on the SL +uh there's no + + align:start position:0% +uh there's no + + + align:start position:0% +uh there's no +like expression for Q it's here keep + + align:start position:0% +like expression for Q it's here keep + + + align:start position:0% +like expression for Q it's here keep +going forever it doesn't stop yeah it + + align:start position:0% +going forever it doesn't stop yeah it + + + align:start position:0% +going forever it doesn't stop yeah it +just discounted more and more and more + + align:start position:0% +just discounted more and more and more + + + align:start position:0% +just discounted more and more and more +so you would expect it to be less and + + align:start position:0% +so you would expect it to be less and + + + align:start position:0% +so you would expect it to be less and +less important but if the thing is + + align:start position:0% +less important but if the thing is + + + align:start position:0% +less important but if the thing is +blowing up then you know it maybe it may + + align:start position:0% +blowing up then you know it maybe it may + + + align:start position:0% +blowing up then you know it maybe it may +dominate the the the the heavier and + + align:start position:0% +dominate the the the the heavier and + + + align:start position:0% +dominate the the the the heavier and +heavier discounting because it's further + + align:start position:0% +heavier discounting because it's further + + + align:start position:0% +heavier discounting because it's further +further out in the future and that's the + + align:start position:0% +further out in the future and that's the + + + align:start position:0% +further out in the future and that's the +way you create theories of bubbles you + + align:start position:0% +way you create theories of bubbles you + + + align:start position:0% +way you create theories of bubbles you +can even come up with rational bubbles + + align:start position:0% +can even come up with rational bubbles + + + align:start position:0% +can even come up with rational bubbles +into the way but again that's what of + + align:start position:0% +into the way but again that's what of + + + align:start position:0% +into the way but again that's what of +course uh what else ah then we look at + + align:start position:0% +course uh what else ah then we look at + + + align:start position:0% +course uh what else ah then we look at +what is the effect of an expansionary + + align:start position:0% +what is the effect of an expansionary + + + align:start position:0% +what is the effect of an expansionary +monetary policy on asset prices and we + + align:start position:0% +monetary policy on asset prices and we + + + align:start position:0% +monetary policy on asset prices and we +said well obviously it's going to if + + align:start position:0% +said well obviously it's going to if + + + align:start position:0% +said well obviously it's going to if +lower interest rate that's going to + + align:start position:0% +lower interest rate that's going to + + + align:start position:0% +lower interest rate that's going to +increase the value of any asset that + + align:start position:0% +increase the value of any asset that + + + align:start position:0% +increase the value of any asset that +pays in the future returns and so it + + align:start position:0% +pays in the future returns and so it + + + align:start position:0% +pays in the future returns and so it +typically is typically the case that + + align:start position:0% +typically is typically the case that + + + align:start position:0% +typically is typically the case that +that expansion in Monet monetary policy + + align:start position:0% +that expansion in Monet monetary policy + + + align:start position:0% +that expansion in Monet monetary policy +will lead to an appreciation of all + + align:start position:0% +will lead to an appreciation of all + + + align:start position:0% +will lead to an appreciation of all +assets uh most assets but certainly + + align:start position:0% +assets uh most assets but certainly + + + align:start position:0% +assets uh most assets but certainly +bonds will go up directly because that's + + align:start position:0% +bonds will go up directly because that's + + + align:start position:0% +bonds will go up directly because that's +where the interest rate has the maximum + + align:start position:0% +where the interest rate has the maximum + + + align:start position:0% +where the interest rate has the maximum +the clearest effect but it's also the + + align:start position:0% +the clearest effect but it's also the + + + align:start position:0% +the clearest effect but it's also the +case that it tends to be bullish for + + align:start position:0% +case that it tends to be bullish for + + + align:start position:0% +case that it tends to be bullish for +Equity as well no it's that got interest + + align:start position:0% +Equity as well no it's that got interest + + + align:start position:0% +Equity as well no it's that got interest +rate and that a lot of the response of + + align:start position:0% +rate and that a lot of the response of + + + align:start position:0% +rate and that a lot of the response of +equity to news has to do with expected + + align:start position:0% +equity to news has to do with expected + + + align:start position:0% +equity to news has to do with expected +behavior of the FED in the future do you + + align:start position:0% +behavior of the FED in the future do you + + + align:start position:0% +behavior of the FED in the future do you +think that this will lead them to + + align:start position:0% +think that this will lead them to + + + align:start position:0% +think that this will lead them to +increase interest rate or to lower + + align:start position:0% +increase interest rate or to lower + + + align:start position:0% +increase interest rate or to lower +interest rate and things of that kind + + align:start position:0% +interest rate and things of that kind + + + align:start position:0% +interest rate and things of that kind +and again I think that's a little too + + align:start position:0% +and again I think that's a little too + + + align:start position:0% +and again I think that's a little too +complicated for you for + + align:start position:0% +complicated for you for + + + align:start position:0% +complicated for you for +now it said what is the effect of an + + align:start position:0% +now it said what is the effect of an + + + align:start position:0% +now it said what is the effect of an +increase in consumer spending on asset + + align:start position:0% +increase in consumer spending on asset + + + align:start position:0% +increase in consumer spending on asset +prices well that depends I mean it's + + align:start position:0% +prices well that depends I mean it's + + + align:start position:0% +prices well that depends I mean it's +clear that that if consumers become more + + align:start position:0% +clear that that if consumers become more + + + align:start position:0% +clear that that if consumers become more +bullish that's going to tend to lead to + + align:start position:0% +bullish that's going to tend to lead to + + + align:start position:0% +bullish that's going to tend to lead to +more cash flows for the firms so Equity + + align:start position:0% +more cash flows for the firms so Equity + + + align:start position:0% +more cash flows for the firms so Equity +at least will go up bonds no because + + align:start position:0% +at least will go up bonds no because + + + align:start position:0% +at least will go up bonds no because +they don't the coupon is set fixed + + align:start position:0% +they don't the coupon is set fixed + + + align:start position:0% +they don't the coupon is set fixed +doesn't depend on whether the econom is + + align:start position:0% +doesn't depend on whether the econom is + + + align:start position:0% +doesn't depend on whether the econom is +doing better or worse I'm assuming + + align:start position:0% +doing better or worse I'm assuming + + + align:start position:0% +doing better or worse I'm assuming +there's no default risk ER but it + + align:start position:0% +there's no default risk ER but it + + + align:start position:0% +there's no default risk ER but it +depends a lot of what you expect the FED + + align:start position:0% +depends a lot of what you expect the FED + + + align:start position:0% +depends a lot of what you expect the FED +to do if the FED if you think that this + + align:start position:0% +to do if the FED if you think that this + + + align:start position:0% +to do if the FED if you think that this +is going to trigger a Fed hike then it's + + align:start position:0% +is going to trigger a Fed hike then it's + + + align:start position:0% +is going to trigger a Fed hike then it's +bad news for bonds you know because the + + align:start position:0% +bad news for bonds you know because the + + + align:start position:0% +bad news for bonds you know because the +F the bonds do not benefit from the + + align:start position:0% +F the bonds do not benefit from the + + + align:start position:0% +F the bonds do not benefit from the +economic activity and and they get hurt + + align:start position:0% +economic activity and and they get hurt + + + align:start position:0% +economic activity and and they get hurt +by higher interest rate so it depends a + + align:start position:0% +by higher interest rate so it depends a + + + align:start position:0% +by higher interest rate so it depends a +lot on what you anticipate the FED to do + + align:start position:0% +lot on what you anticipate the FED to do + + + align:start position:0% +lot on what you anticipate the FED to do +or not but again I think this is a bit + + align:start position:0% +or not but again I think this is a bit + + + align:start position:0% +or not but again I think this is a bit +more complicated than what you need to + + align:start position:0% +more complicated than what you need to + + + align:start position:0% +more complicated than what you need to +know okay the last step was + + align:start position:0% +know okay the last step was + + + align:start position:0% +know okay the last step was +to H bring expectations into the aslm + + align:start position:0% +to H bring expectations into the aslm + + + align:start position:0% +to H bring expectations into the aslm +model I said the model we discussed + + align:start position:0% +model I said the model we discussed + + + align:start position:0% +model I said the model we discussed +through the course on the aslm except + + align:start position:0% +through the course on the aslm except + + + align:start position:0% +through the course on the aslm except +for the part where we put the exchange + + align:start position:0% +for the part where we put the exchange + + + align:start position:0% +for the part where we put the exchange +rate where we you know we we have to + + align:start position:0% +rate where we you know we we have to + + + align:start position:0% +rate where we you know we we have to +think about the future exchange rates + + align:start position:0% +think about the future exchange rates + + + align:start position:0% +think about the future exchange rates +and things like that it was really + + align:start position:0% +and things like that it was really + + + align:start position:0% +and things like that it was really +overweight the present in reality + + align:start position:0% +overweight the present in reality + + + align:start position:0% +overweight the present in reality +expectations matter a lot for consu + + align:start position:0% +expectations matter a lot for consu + + + align:start position:0% +expectations matter a lot for consu +consumers decisions for firm's decisions + + align:start position:0% +consumers decisions for firm's decisions + + + align:start position:0% +consumers decisions for firm's decisions +and so on probably matters even more + + align:start position:0% +and so on probably matters even more + + + align:start position:0% +and so on probably matters even more +than the future than the present okay + + align:start position:0% +than the future than the present okay + + + align:start position:0% +than the future than the present okay +ER and so so what we did is we expanded + + align:start position:0% +ER and so so what we did is we expanded + + + align:start position:0% +ER and so so what we did is we expanded +H the islm to include expectation we see + + align:start position:0% +H the islm to include expectation we see + + + align:start position:0% +H the islm to include expectation we see +well consumers not only worry about + + align:start position:0% +well consumers not only worry about + + + align:start position:0% +well consumers not only worry about +disposable income this part will show up + + align:start position:0% +disposable income this part will show up + + + align:start position:0% +disposable income this part will show up +in your test so so you should understand + + align:start position:0% +in your test so so you should understand + + + align:start position:0% +in your test so so you should understand +what what the eslm model is and do the + + align:start position:0% +what what the eslm model is and do the + + + align:start position:0% +what what the eslm model is and do the +comparative Statics that correspond to + + align:start position:0% +comparative Statics that correspond to + + + align:start position:0% +comparative Statics that correspond to +this model so what we did here is as + + align:start position:0% +this model so what we did here is as + + + align:start position:0% +this model so what we did here is as +well consumers not only worry about the + + align:start position:0% +well consumers not only worry about the + + + align:start position:0% +well consumers not only worry about the +current disposable income H they also + + align:start position:0% +current disposable income H they also + + + align:start position:0% +current disposable income H they also +worry about the income they receive in + + align:start position:0% +worry about the income they receive in + + + align:start position:0% +worry about the income they receive in +the future through financial asset + + align:start position:0% +the future through financial asset + + + align:start position:0% +the future through financial asset +Financial wealth or through their future + + align:start position:0% +Financial wealth or through their future + + + align:start position:0% +Financial wealth or through their future +labor income that's what we call human + + align:start position:0% +labor income that's what we call human + + + align:start position:0% +labor income that's what we call human +wealth but the point is that + + align:start position:0% +wealth but the point is that + + + align:start position:0% +wealth but the point is that +expectations about the future matter for + + align:start position:0% +expectations about the future matter for + + + align:start position:0% +expectations about the future matter for +consumption in the first part of the + + align:start position:0% +consumption in the first part of the + + + align:start position:0% +consumption in the first part of the +course we we summarize all that in that + + align:start position:0% +course we we summarize all that in that + + + align:start position:0% +course we we summarize all that in that +little parameters c0 which said + + align:start position:0% +little parameters c0 which said + + + align:start position:0% +little parameters c0 which said +consumers can be bullish or not but a + + align:start position:0% +consumers can be bullish or not but a + + + align:start position:0% +consumers can be bullish or not but a +lot of what happens here is what shifts + + align:start position:0% +lot of what happens here is what shifts + + + align:start position:0% +lot of what happens here is what shifts +c0 in the first part of the of the + + align:start position:0% +c0 in the first part of the of the + + + align:start position:0% +c0 in the first part of the of the +course and and this also highlight an + + align:start position:0% +course and and this also highlight an + + + align:start position:0% +course and and this also highlight an +important concept which is typically if + + align:start position:0% +important concept which is typically if + + + align:start position:0% +important concept which is typically if +you expect something to have only a + + align:start position:0% +you expect something to have only a + + + align:start position:0% +you expect something to have only a +temporary transitory consequence it will + + align:start position:0% +temporary transitory consequence it will + + + align:start position:0% +temporary transitory consequence it will +move consumption little relative to when + + align:start position:0% +move consumption little relative to when + + + align:start position:0% +move consumption little relative to when +you expect that change to be permanent + + align:start position:0% +you expect that change to be permanent + + + align:start position:0% +you expect that change to be permanent +so you expect current income to be up + + align:start position:0% +so you expect current income to be up + + + align:start position:0% +so you expect current income to be up +but but future income to go back to a + + align:start position:0% +but but future income to go back to a + + + align:start position:0% +but but future income to go back to a +lower level that's not going to change + + align:start position:0% +lower level that's not going to change + + + align:start position:0% +lower level that's not going to change +current consumption a lot however if you + + align:start position:0% +current consumption a lot however if you + + + align:start position:0% +current consumption a lot however if you +think there's a change that will + + align:start position:0% +think there's a change that will + + + align:start position:0% +think there's a change that will +increase in consumers income permanently + + align:start position:0% +increase in consumers income permanently + + + align:start position:0% +increase in consumers income permanently +up well that will increase not only this + + align:start position:0% +up well that will increase not only this + + + align:start position:0% +up well that will increase not only this +but also wealth human wealth and that + + align:start position:0% +but also wealth human wealth and that + + + align:start position:0% +but also wealth human wealth and that +will lead to a much larger response of + + align:start position:0% +will lead to a much larger response of + + + align:start position:0% +will lead to a much larger response of +consumption + + align:start position:0% +consumption + + + align:start position:0% +consumption +okay we did more or less for the same + + align:start position:0% +okay we did more or less for the same + + + align:start position:0% +okay we did more or less for the same +for investment obviously what matters + + align:start position:0% +for investment obviously what matters + + + align:start position:0% +for investment obviously what matters +for investment is the is future cash + + align:start position:0% +for investment is the is future cash + + + align:start position:0% +for investment is the is future cash +flows and and there we talk about the + + align:start position:0% +flows and and there we talk about the + + + align:start position:0% +flows and and there we talk about the +concept of depreciation but really was + + align:start position:0% +concept of depreciation but really was + + + align:start position:0% +concept of depreciation but really was +this was expected present discounted + + align:start position:0% +this was expected present discounted + + + align:start position:0% +this was expected present discounted +value of the cash flow generated by by + + align:start position:0% +value of the cash flow generated by by + + + align:start position:0% +value of the cash flow generated by by +an extra unit of capital so expected per + + align:start position:0% +an extra unit of capital so expected per + + + align:start position:0% +an extra unit of capital so expected per +Val discounted value + + align:start position:0% +Val discounted value + + + align:start position:0% +Val discounted value +formula so we said you know we we in the + + align:start position:0% +formula so we said you know we we in the + + + align:start position:0% +formula so we said you know we we in the +first part of the course we just look at + + align:start position:0% +first part of the course we just look at + + + align:start position:0% +first part of the course we just look at +an investment function that has output + + align:start position:0% +an investment function that has output + + + align:start position:0% +an investment function that has output +here and then we have an interest rate + + align:start position:0% +here and then we have an interest rate + + + align:start position:0% +here and then we have an interest rate +here where now we have something that's + + align:start position:0% +here where now we have something that's + + + align:start position:0% +here where now we have something that's +more complicated has future output which + + align:start position:0% +more complicated has future output which + + + align:start position:0% +more complicated has future output which +has appr proxim for future cash flows + + align:start position:0% +has appr proxim for future cash flows + + + align:start position:0% +has appr proxim for future cash flows +but also current and future interest + + align:start position:0% +but also current and future interest + + + align:start position:0% +but also current and future interest +rates because those affect the value of + + align:start position:0% +rates because those affect the value of + + + align:start position:0% +rates because those affect the value of +those future cash flows H in terms of + + align:start position:0% +those future cash flows H in terms of + + + align:start position:0% +those future cash flows H in terms of +today's + + align:start position:0% +today's + + + align:start position:0% +today's +dollars and we put all of this together + + align:start position:0% +dollars and we put all of this together + + + align:start position:0% +dollars and we put all of this together +and we ended up with an expanded + + align:start position:0% +and we ended up with an expanded + + + align:start position:0% +and we ended up with an expanded +aggregate demand in which ER you know in + + align:start position:0% +aggregate demand in which ER you know in + + + align:start position:0% +aggregate demand in which ER you know in +which we had the same parameters that we + + align:start position:0% +which we had the same parameters that we + + + align:start position:0% +which we had the same parameters that we +had ER when we did the static + + align:start position:0% +had ER when we did the static + + + align:start position:0% +had ER when we did the static +model without expectations but now we + + align:start position:0% +model without expectations but now we + + + align:start position:0% +model without expectations but now we +get sort of the same things repeated + + align:start position:0% +get sort of the same things repeated + + + align:start position:0% +get sort of the same things repeated +here one year ahead because it it + + align:start position:0% +here one year ahead because it it + + + align:start position:0% +here one year ahead because it it +matters not only for aggregate demand + + align:start position:0% +matters not only for aggregate demand + + + align:start position:0% +matters not only for aggregate demand +not only the income the consumers are + + align:start position:0% +not only the income the consumers are + + + align:start position:0% +not only the income the consumers are +receiving today or the sales that firms + + align:start position:0% +receiving today or the sales that firms + + + align:start position:0% +receiving today or the sales that firms +are making today but also what they + + align:start position:0% +are making today but also what they + + + align:start position:0% +are making today but also what they +expect to have next year here it matters + + align:start position:0% +expect to have next year here it matters + + + align:start position:0% +expect to have next year here it matters +what the taxes they're paying today but + + align:start position:0% +what the taxes they're paying today but + + + align:start position:0% +what the taxes they're paying today but +also what they expect to pay in the + + align:start position:0% +also what they expect to pay in the + + + align:start position:0% +also what they expect to pay in the +future the interest rate matters not + + align:start position:0% +future the interest rate matters not + + + align:start position:0% +future the interest rate matters not +only today but also what they expect the + + align:start position:0% +only today but also what they expect the + + + align:start position:0% +only today but also what they expect the +interest rate to be in the future and so + + align:start position:0% +interest rate to be in the future and so + + + align:start position:0% +interest rate to be in the future and so +on okay so the bottom line is that we if + + align:start position:0% +on okay so the bottom line is that we if + + + align:start position:0% +on okay so the bottom line is that we if +we now look at the slm model I said now + + align:start position:0% +we now look at the slm model I said now + + + align:start position:0% +we now look at the slm model I said now +we have lots of more parameters all + + align:start position:0% +we have lots of more parameters all + + + align:start position:0% +we have lots of more parameters all +these things that happen in the future + + align:start position:0% +these things that happen in the future + + + align:start position:0% +these things that happen in the future +are new + + align:start position:0% +are new + + + align:start position:0% +are new +parameters H I said notice notice that + + align:start position:0% +parameters H I said notice notice that + + + align:start position:0% +parameters H I said notice notice that +also this curve now is a lot steeper + + align:start position:0% +also this curve now is a lot steeper + + + align:start position:0% +also this curve now is a lot steeper +why is that well because if you change + + align:start position:0% +why is that well because if you change + + + align:start position:0% +why is that well because if you change +the interest rate today without without + + align:start position:0% +the interest rate today without without + + + align:start position:0% +the interest rate today without without +changing the interest rate in the future + + align:start position:0% +changing the interest rate in the future + + + align:start position:0% +changing the interest rate in the future +then that has a small effect okay and so + + align:start position:0% +then that has a small effect okay and so + + + align:start position:0% +then that has a small effect okay and so +I said now this is becomes very steep + + align:start position:0% +I said now this is becomes very steep + + + align:start position:0% +I said now this is becomes very steep +but the equivalent to what we did the + + align:start position:0% +but the equivalent to what we did the + + + align:start position:0% +but the equivalent to what we did the +static model is a is a situation where + + align:start position:0% +static model is a is a situation where + + + align:start position:0% +static model is a is a situation where +you cut the interest rate today say the + + align:start position:0% +you cut the interest rate today say the + + + align:start position:0% +you cut the interest rate today say the +Central Bank cuts the interest rate + + align:start position:0% +Central Bank cuts the interest rate + + + align:start position:0% +Central Bank cuts the interest rate +today but it also convinces the public + + align:start position:0% +today but it also convinces the public + + + align:start position:0% +today but it also convinces the public +that they will also keep the interest + + align:start position:0% +that they will also keep the interest + + + align:start position:0% +that they will also keep the interest +rate low in the next period that is not + + align:start position:0% +rate low in the next period that is not + + + align:start position:0% +rate low in the next period that is not +only you move along the SAS but you also + + align:start position:0% +only you move along the SAS but you also + + + align:start position:0% +only you move along the SAS but you also +persuade the public that the interest + + align:start position:0% +persuade the public that the interest + + + align:start position:0% +persuade the public that the interest +rate will be lower in the future that + + align:start position:0% +rate will be lower in the future that + + + align:start position:0% +rate will be lower in the future that +will shift yes to the right and then + + align:start position:0% +will shift yes to the right and then + + + align:start position:0% +will shift yes to the right and then +therefore therefore you're going to get + + align:start position:0% +therefore therefore you're going to get + + + align:start position:0% +therefore therefore you're going to get +a much larger kick out of monetary + + align:start position:0% +a much larger kick out of monetary + + + align:start position:0% +a much larger kick out of monetary +policy and pol monetary policy is a lot + + align:start position:0% +policy and pol monetary policy is a lot + + + align:start position:0% +policy and pol monetary policy is a lot +about forward guidance is that you know + + align:start position:0% +about forward guidance is that you know + + + align:start position:0% +about forward guidance is that you know +you cut interest rate today but you're + + align:start position:0% +you cut interest rate today but you're + + + align:start position:0% +you cut interest rate today but you're +also telling there's always a speech + + align:start position:0% +also telling there's always a speech + + + align:start position:0% +also telling there's always a speech +after they they take the policy action + + align:start position:0% +after they they take the policy action + + + align:start position:0% +after they they take the policy action +which they talk about how they see + + align:start position:0% +which they talk about how they see + + + align:start position:0% +which they talk about how they see +interest rates going in the future and + + align:start position:0% +interest rates going in the future and + + + align:start position:0% +interest rates going in the future and +all of that that's because you want to + + align:start position:0% +all of that that's because you want to + + + align:start position:0% +all of that that's because you want to +have maximum power okay if you if if you + + align:start position:0% +have maximum power okay if you if if you + + + align:start position:0% +have maximum power okay if you if if you +just tell the market I'm going to change + + align:start position:0% +just tell the market I'm going to change + + + align:start position:0% +just tell the market I'm going to change +the interest rate for now and then + + align:start position:0% +the interest rate for now and then + + + align:start position:0% +the interest rate for now and then +nothing else that's going to have a very + + align:start position:0% +nothing else that's going to have a very + + + align:start position:0% +nothing else that's going to have a very +limited impact to have a large impact + + align:start position:0% +limited impact to have a large impact + + + align:start position:0% +limited impact to have a large impact +out of monetary policy you have to + + align:start position:0% +out of monetary policy you have to + + + align:start position:0% +out of monetary policy you have to +convince them that you will also affect + + align:start position:0% +convince them that you will also affect + + + align:start position:0% +convince them that you will also affect +the interest R path in the + + align:start position:0% +the interest R path in the + + + align:start position:0% +the interest R path in the +future same sort of situation here the + + align:start position:0% +future same sort of situation here the + + + align:start position:0% +future same sort of situation here the +other parameters is what happens if for + + align:start position:0% +other parameters is what happens if for + + + align:start position:0% +other parameters is what happens if for +example you expect future output to go + + align:start position:0% +example you expect future output to go + + + align:start position:0% +example you expect future output to go +up H well that's going to shift a yes to + + align:start position:0% +up H well that's going to shift a yes to + + + align:start position:0% +up H well that's going to shift a yes to +the right that's yet another reason why + + align:start position:0% +the right that's yet another reason why + + + align:start position:0% +the right that's yet another reason why +convincing people that you're going to + + align:start position:0% +convincing people that you're going to + + + align:start position:0% +convincing people that you're going to +cut interest rate in the future as well + + align:start position:0% +cut interest rate in the future as well + + + align:start position:0% +cut interest rate in the future as well +they going to keep them low in the + + align:start position:0% +they going to keep them low in the + + + align:start position:0% +they going to keep them low in the +future shift yes even more because if + + align:start position:0% +future shift yes even more because if + + + align:start position:0% +future shift yes even more because if +you're going to keep the interest rate + + align:start position:0% +you're going to keep the interest rate + + + align:start position:0% +you're going to keep the interest rate +low in the future that means probably + + align:start position:0% +low in the future that means probably + + + align:start position:0% +low in the future that means probably +the future output will be higher and + + align:start position:0% +the future output will be higher and + + + align:start position:0% +the future output will be higher and +since future output is higher that + + align:start position:0% +since future output is higher that + + + align:start position:0% +since future output is higher that +increases human wealth and that means + + align:start position:0% +increases human wealth and that means + + + align:start position:0% +increases human wealth and that means +consumption will tend to go up okay but + + align:start position:0% +consumption will tend to go up okay but + + + align:start position:0% +consumption will tend to go up okay but +do play with this and and again the the + + align:start position:0% +do play with this and and again the the + + + align:start position:0% +do play with this and and again the the +it's important to have this distinction + + align:start position:0% +it's important to have this distinction + + + align:start position:0% +it's important to have this distinction +between the impact of temporary things + + align:start position:0% +between the impact of temporary things + + + align:start position:0% +between the impact of temporary things +which is much smaller and and the the + + align:start position:0% +which is much smaller and and the the + + + align:start position:0% +which is much smaller and and the the +impact of permanent things which is + + align:start position:0% +impact of permanent things which is + + + align:start position:0% +impact of permanent things which is +bigger because it affect + + align:start position:0% +bigger because it affect + + + align:start position:0% +bigger because it affect +wealth + + align:start position:0% + + + + align:start position:0% + +okay oh that's an example okay so + + align:start position:0% +okay oh that's an example okay so + + + align:start position:0% +okay oh that's an example okay so +monetary policy again ER that's just if + + align:start position:0% +monetary policy again ER that's just if + + + align:start position:0% +monetary policy again ER that's just if +if you don't persuade the public that + + align:start position:0% +if you don't persuade the public that + + + align:start position:0% +if you don't persuade the public that +you're going to change the interest rate + + align:start position:0% +you're going to change the interest rate + + + align:start position:0% +you're going to change the interest rate +in the future then it just a movement + + align:start position:0% +in the future then it just a movement + + + align:start position:0% +in the future then it just a movement +along but if you also convince them that + + align:start position:0% +along but if you also convince them that + + + align:start position:0% +along but if you also convince them that +you will remain sort of H lose monetary + + align:start position:0% +you will remain sort of H lose monetary + + + align:start position:0% +you will remain sort of H lose monetary +conditions in next year then that that + + align:start position:0% +conditions in next year then that that + + + align:start position:0% +conditions in next year then that that +effectively shift the yes to the right + + align:start position:0% +effectively shift the yes to the right + + + align:start position:0% +effectively shift the yes to the right +for for a variety of Reon for two + + align:start position:0% +for for a variety of Reon for two + + + align:start position:0% +for for a variety of Reon for two +reasons at least that's much more + + align:start position:0% +reasons at least that's much more + + + align:start position:0% +reasons at least that's much more +expansionary the last thing we did is + + align:start position:0% +expansionary the last thing we did is + + + align:start position:0% +expansionary the last thing we did is +fiscal policy I said well fiscal policy + + align:start position:0% +fiscal policy I said well fiscal policy + + + align:start position:0% +fiscal policy I said well fiscal policy +fiscal policy today is contraction and + + align:start position:0% +fiscal policy today is contraction and + + + align:start position:0% +fiscal policy today is contraction and +there's no doubt of that but it can have + + align:start position:0% +there's no doubt of that but it can have + + + align:start position:0% +there's no doubt of that but it can have +but there are episodes and I show you + + align:start position:0% +but there are episodes and I show you + + + align:start position:0% +but there are episodes and I show you +the Irish episode in which actually may + + align:start position:0% +the Irish episode in which actually may + + + align:start position:0% +the Irish episode in which actually may +end up going the other way around in + + align:start position:0% +end up going the other way around in + + + align:start position:0% +end up going the other way around in +which you cut expenditure today which is + + align:start position:0% +which you cut expenditure today which is + + + align:start position:0% +which you cut expenditure today which is +contractionary but you end up actually + + align:start position:0% +contractionary but you end up actually + + + align:start position:0% +contractionary but you end up actually +having an expansion but for that the + + align:start position:0% +having an expansion but for that the + + + align:start position:0% +having an expansion but for that the +only way that can happen is that if + + align:start position:0% +only way that can happen is that if + + + align:start position:0% +only way that can happen is that if +somehow you affect expectations in a + + align:start position:0% +somehow you affect expectations in a + + + align:start position:0% +somehow you affect expectations in a +very significant way so that's what I + + align:start position:0% +very significant way so that's what I + + + align:start position:0% +very significant way so that's what I +said if if you ever get sort of a a a + + align:start position:0% +said if if you ever get sort of a a a + + + align:start position:0% +said if if you ever get sort of a a a +strange correl response to to a policy + + align:start position:0% +strange correl response to to a policy + + + align:start position:0% +strange correl response to to a policy +announcement is probably because there + + align:start position:0% +announcement is probably because there + + + align:start position:0% +announcement is probably because there +has been a big effect on expectations so + + align:start position:0% +has been a big effect on expectations so + + + align:start position:0% +has been a big effect on expectations so +I show you the case of Ireland because + + align:start position:0% +I show you the case of Ireland because + + + align:start position:0% +I show you the case of Ireland because +there a case that was famous in which + + align:start position:0% +there a case that was famous in which + + + align:start position:0% +there a case that was famous in which +all the people talk about there was a + + align:start position:0% +all the people talk about there was a + + + align:start position:0% +all the people talk about there was a +fiscal deficit as the big drug in the + + align:start position:0% +fiscal deficit as the big drug in the + + + align:start position:0% +fiscal deficit as the big drug in the +economy that there was going to be a big + + align:start position:0% +economy that there was going to be a big + + + align:start position:0% +economy that there was going to be a big +Day of Reckoning and that you and so on + + align:start position:0% +Day of Reckoning and that you and so on + + + align:start position:0% +Day of Reckoning and that you and so on +so forth so once they dealt with it sort + + align:start position:0% +so forth so once they dealt with it sort + + + align:start position:0% +so forth so once they dealt with it sort +of expectations they realize they could + + align:start position:0% +of expectations they realize they could + + + align:start position:0% +of expectations they realize they could +cut interest rates then they could + + align:start position:0% +cut interest rates then they could + + + align:start position:0% +cut interest rates then they could +realiz that that that also that that + + align:start position:0% +realiz that that that also that that + + + align:start position:0% +realiz that that that also that that +this Malay and the economy was going to + + align:start position:0% +this Malay and the economy was going to + + + align:start position:0% +this Malay and the economy was going to +go away so people became optimistic + + align:start position:0% +go away so people became optimistic + + + align:start position:0% +go away so people became optimistic +about the future and so on and they end + + align:start position:0% +about the future and so on and they end + + + align:start position:0% +about the future and so on and they end +up with an expansion okay that shows you + + align:start position:0% +up with an expansion okay that shows you + + + align:start position:0% +up with an expansion okay that shows you +how important expectations are so + + align:start position:0% +how important expectations are so + + + align:start position:0% +how important expectations are so +economic policy in general you the the + + align:start position:0% +economic policy in general you the the + + + align:start position:0% +economic policy in general you the the +direct immediate effect is what we have + + align:start position:0% +direct immediate effect is what we have + + + align:start position:0% +direct immediate effect is what we have +been discussing throughout the course + + align:start position:0% +been discussing throughout the course + + + align:start position:0% +been discussing throughout the course +but a lot of its power and even the sort + + align:start position:0% +but a lot of its power and even the sort + + + align:start position:0% +but a lot of its power and even the sort +of perverse or or or or good synergies + + align:start position:0% +of perverse or or or or good synergies + + + align:start position:0% +of perverse or or or or good synergies +that you get out of them has to do with + + align:start position:0% +that you get out of them has to do with + + + align:start position:0% +that you get out of them has to do with +what you do to with expect patience okay + + align:start position:0% +what you do to with expect patience okay + + + align:start position:0% +what you do to with expect patience okay +good \ No newline at end of file diff --git a/tZw_eux9Wno.txt b/tZw_eux9Wno.txt new file mode 100644 index 0000000000000000000000000000000000000000..d7c7d16b8c98a5098f08c6ba02755f988691e80c --- /dev/null +++ b/tZw_eux9Wno.txt @@ -0,0 +1,1325 @@ +align:start position:0% + +Hi guys. Um, my name is Nicola and in + + align:start position:0% +Hi guys. Um, my name is Nicola and in + + + align:start position:0% +Hi guys. Um, my name is Nicola and in +this video we're going to work out an + + align:start position:0% +this video we're going to work out an + + + align:start position:0% +this video we're going to work out an +example of an orthogonal projection + + align:start position:0% +example of an orthogonal projection + + + align:start position:0% +example of an orthogonal projection +matrix. Specifically, we are going to + + align:start position:0% +matrix. Specifically, we are going to + + + align:start position:0% +matrix. Specifically, we are going to +compute the projection matrix onto the + + align:start position:0% +compute the projection matrix onto the + + + align:start position:0% +compute the projection matrix onto the +plane given by the equation x + y minus + + align:start position:0% +plane given by the equation x + y minus + + + align:start position:0% +plane given by the equation x + y minus +z equals z. So before we start, uh, let + + align:start position:0% +z equals z. So before we start, uh, let + + + align:start position:0% +z equals z. So before we start, uh, let +me just recall what a projection matrix + + align:start position:0% +me just recall what a projection matrix + + + align:start position:0% +me just recall what a projection matrix +is. + + align:start position:0% +is. + + + align:start position:0% +is. +So you've seen um this sketch here a + + align:start position:0% +So you've seen um this sketch here a + + + align:start position:0% +So you've seen um this sketch here a +million times already. Uh a projection + + align:start position:0% +million times already. Uh a projection + + + align:start position:0% +million times already. Uh a projection +matrix takes any vector in three space. + + align:start position:0% +matrix takes any vector in three space. + + + align:start position:0% +matrix takes any vector in three space. +Well in just in this case we're dealing + + align:start position:0% +Well in just in this case we're dealing + + + align:start position:0% +Well in just in this case we're dealing +with a free space and projects it down + + align:start position:0% +with a free space and projects it down + + + align:start position:0% +with a free space and projects it down +onto the plane um a two dimensional + + align:start position:0% +onto the plane um a two dimensional + + + align:start position:0% +onto the plane um a two dimensional +space subspace of of R3. So I'm g give + + align:start position:0% +space subspace of of R3. So I'm g give + + + align:start position:0% +space subspace of of R3. So I'm g give +you a few moments to uh consider the + + align:start position:0% +you a few moments to uh consider the + + + align:start position:0% +you a few moments to uh consider the +problem for yourselves and then you'll + + align:start position:0% +problem for yourselves and then you'll + + + align:start position:0% +problem for yourselves and then you'll +see my take on + + align:start position:0% + + + + align:start position:0% + +it again. Okay. So in in lecture + + align:start position:0% +it again. Okay. So in in lecture + + + align:start position:0% +it again. Okay. So in in lecture +professor strang derived in meticulous + + align:start position:0% +professor strang derived in meticulous + + + align:start position:0% +professor strang derived in meticulous +detail the formula for the projection + + align:start position:0% +detail the formula for the projection + + + align:start position:0% +detail the formula for the projection +matrix. So uh it was given by the + + align:start position:0% +matrix. So uh it was given by the + + + align:start position:0% +matrix. So uh it was given by the +following + + align:start position:0% +following + + + align:start position:0% +following +well slightly complicated expression. + + align:start position:0% +well slightly complicated expression. + + + align:start position:0% +well slightly complicated expression. +It's a * a transpose a + + align:start position:0% +It's a * a transpose a + + + align:start position:0% +It's a * a transpose a +inverse a transpose where a is a matrix + + align:start position:0% +inverse a transpose where a is a matrix + + + align:start position:0% +inverse a transpose where a is a matrix +that somehow encodes the subspace we're + + align:start position:0% +that somehow encodes the subspace we're + + + align:start position:0% +that somehow encodes the subspace we're +projecting + + align:start position:0% +projecting + + + align:start position:0% +projecting +on. Yeah. In particular, A is has as + + align:start position:0% +on. Yeah. In particular, A is has as + + + align:start position:0% +on. Yeah. In particular, A is has as +columns A1, A2. I'm going to denote them + + align:start position:0% +columns A1, A2. I'm going to denote them + + + align:start position:0% +columns A1, A2. I'm going to denote them +a basis for the plane we're projecting + + align:start position:0% +a basis for the plane we're projecting + + + align:start position:0% +a basis for the plane we're projecting +on. Um, so essentially what we need to + + align:start position:0% +on. Um, so essentially what we need to + + + align:start position:0% +on. Um, so essentially what we need to +do is find two such vectors that span + + align:start position:0% +do is find two such vectors that span + + + align:start position:0% +do is find two such vectors that span +the plane and start computing with the + + align:start position:0% +the plane and start computing with the + + + align:start position:0% +the plane and start computing with the +matrix. Um, it's yeah, this is fairly + + align:start position:0% +matrix. Um, it's yeah, this is fairly + + + align:start position:0% +matrix. Um, it's yeah, this is fairly +straightforward. + + align:start position:0% + + + + align:start position:0% + +Uh one one choice that works for example + + align:start position:0% +Uh one one choice that works for example + + + align:start position:0% +Uh one one choice that works for example +is + + align:start position:0% +is + + + align:start position:0% +is +one zero for the first column + + align:start position:0% +one zero for the first column + + + align:start position:0% +one zero for the first column +and 1 0 1 for the second column. + + align:start position:0% +and 1 0 1 for the second column. + + + align:start position:0% +and 1 0 1 for the second column. +Okay. Uh and let me write out the matrix + + align:start position:0% +Okay. Uh and let me write out the matrix + + + align:start position:0% +Okay. Uh and let me write out the matrix +A. + + align:start position:0% + + + + align:start position:0% + +Okay. So in the formula um + + align:start position:0% +Okay. So in the formula um + + + align:start position:0% +Okay. So in the formula um +the I guess the more slightly more + + align:start position:0% +the I guess the more slightly more + + + align:start position:0% +the I guess the more slightly more +complicated uh combination is a + + align:start position:0% +complicated uh combination is a + + + align:start position:0% +complicated uh combination is a +transpose a inverse. So let me compute + + align:start position:0% +transpose a inverse. So let me compute + + + align:start position:0% +transpose a inverse. So let me compute +that first for you. Uh okay. So a + + align:start position:0% +that first for you. Uh okay. So a + + + align:start position:0% +that first for you. Uh okay. So a +transpose a + + align:start position:0% +transpose a + + + align:start position:0% +transpose a +is a 2x two + + align:start position:0% +is a 2x two + + + align:start position:0% +is a 2x two +matrix and it's not so hard to figure + + align:start position:0% +matrix and it's not so hard to figure + + + align:start position:0% +matrix and it's not so hard to figure +out that it's like two and one one two. + + align:start position:0% +out that it's like two and one one two. + + + align:start position:0% +out that it's like two and one one two. +Okay. Now we shall invert + + align:start position:0% + + + + align:start position:0% + +it using the familiar formula one over + + align:start position:0% +it using the familiar formula one over + + + align:start position:0% +it using the familiar formula one over +the determinant 2 * 2 - 1 is + + align:start position:0% +the determinant 2 * 2 - 1 is + + + align:start position:0% +the determinant 2 * 2 - 1 is +three + + align:start position:0% +three + + + align:start position:0% +three +and so we switch the diagonal + + align:start position:0% +and so we switch the diagonal + + + align:start position:0% +and so we switch the diagonal +entries and we flip the signs of the of + + align:start position:0% +entries and we flip the signs of the of + + + align:start position:0% +entries and we flip the signs of the of +diagonal ones + + align:start position:0% +diagonal ones + + + align:start position:0% +diagonal ones +okay right and + + align:start position:0% +okay right and + + + align:start position:0% +okay right and +therefore projection matrix is given by + + align:start position:0% +therefore projection matrix is given by + + + align:start position:0% +therefore projection matrix is given by +the following uh product of matrices + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% + + + + align:start position:0% + +is 1/3 + + align:start position:0% +is 1/3 + + + align:start position:0% +is 1/3 +21 2 and + + align:start position:0% +21 2 and + + + align:start position:0% +21 2 and +then transpose of A which + + align:start position:0% +then transpose of A which + + + align:start position:0% +then transpose of A which +is 1 0 1 0 1 + + align:start position:0% +is 1 0 1 0 1 + + + align:start position:0% +is 1 0 1 0 1 +Okay, I'm going to carry out this + + align:start position:0% +Okay, I'm going to carry out this + + + align:start position:0% +Okay, I'm going to carry out this +multiplication in an inhumanly fast + + align:start position:0% +multiplication in an inhumanly fast + + + align:start position:0% +multiplication in an inhumanly fast +fashion. + + align:start position:0% +fashion. + + + align:start position:0% +fashion. +So, I'm just going to write down the + + align:start position:0% +So, I'm just going to write down the + + + align:start position:0% +So, I'm just going to write down the +answer, which is a + + align:start position:0% +answer, which is a + + + align:start position:0% +answer, which is a +third + + align:start position:0% +third + + + align:start position:0% +third + + align:start position:0% + + + align:start position:0% +1 2 2 one one + + align:start position:0% + + + + align:start position:0% + +one. Right. So what you can do now is + + align:start position:0% +one. Right. So what you can do now is + + + align:start position:0% +one. Right. So what you can do now is +well you can check whether this answer + + align:start position:0% +well you can check whether this answer + + + align:start position:0% +well you can check whether this answer +actually makes sense. One thing you can + + align:start position:0% +actually makes sense. One thing you can + + + align:start position:0% +actually makes sense. One thing you can +do is just well a projection matrix is + + align:start position:0% +do is just well a projection matrix is + + + align:start position:0% +do is just well a projection matrix is +supposed to take the normal to the plane + + align:start position:0% +supposed to take the normal to the plane + + + align:start position:0% +supposed to take the normal to the plane +down to zero. So you can just multiply P + + align:start position:0% +down to zero. So you can just multiply P + + + align:start position:0% +down to zero. So you can just multiply P +and the normal vector one one negative + + align:start position:0% +and the normal vector one one negative + + + align:start position:0% +and the normal vector one one negative +one and if you get zero maybe you've + + align:start position:0% +one and if you get zero maybe you've + + + align:start position:0% +one and if you get zero maybe you've +done a good job. Um, another curious + + align:start position:0% +done a good job. Um, another curious + + + align:start position:0% +done a good job. Um, another curious +thing that I would like to point out + + align:start position:0% +thing that I would like to point out + + + align:start position:0% +thing that I would like to point out +here is so you see we had lots of + + align:start position:0% +here is so you see we had lots of + + + align:start position:0% +here is so you see we had lots of +freedom of choosing the matrix A. I mean + + align:start position:0% +freedom of choosing the matrix A. I mean + + + align:start position:0% +freedom of choosing the matrix A. I mean +you could have we could have chosen any + + align:start position:0% +you could have we could have chosen any + + + align:start position:0% +you could have we could have chosen any +two columns that span the subspace that + + align:start position:0% +two columns that span the subspace that + + + align:start position:0% +two columns that span the subspace that +spans the plane. The beautiful thing + + align:start position:0% +spans the plane. The beautiful thing + + + align:start position:0% +spans the plane. The beautiful thing +about it is that in the end we will get + + align:start position:0% +about it is that in the end we will get + + + align:start position:0% +about it is that in the end we will get +the same same + + align:start position:0% +the same same + + + align:start position:0% +the same same +answer. Um, + + align:start position:0% +answer. Um, + + + align:start position:0% +answer. Um, +right. So I hope there will be many of + + align:start position:0% +right. So I hope there will be many of + + + align:start position:0% +right. So I hope there will be many of +you who would say hey there is an easier + + align:start position:0% +you who would say hey there is an easier + + + align:start position:0% +you who would say hey there is an easier +way to do the problem and I'll agree + + align:start position:0% +way to do the problem and I'll agree + + + align:start position:0% +way to do the problem and I'll agree +with these people. + + align:start position:0% +with these people. + + + align:start position:0% +with these people. +So let's + + align:start position:0% +So let's + + + align:start position:0% +So let's +yeah let's see what would be an easier + + align:start position:0% +yeah let's see what would be an easier + + + align:start position:0% +yeah let's see what would be an easier +approach. + + align:start position:0% +approach. + + + align:start position:0% +approach. +Well, let's go back to the sketch here, + + align:start position:0% +Well, let's go back to the sketch here, + + + align:start position:0% +Well, let's go back to the sketch here, +right? And let's make the following + + align:start position:0% +right? And let's make the following + + + align:start position:0% +right? And let's make the following +observation that any vector is a sum of + + align:start position:0% +observation that any vector is a sum of + + + align:start position:0% +observation that any vector is a sum of +two components. One, the first component + + align:start position:0% +two components. One, the first component + + + align:start position:0% +two components. One, the first component +is its projection onto the plane and the + + align:start position:0% +is its projection onto the plane and the + + + align:start position:0% +is its projection onto the plane and the +other component is its projection onto + + align:start position:0% +other component is its projection onto + + + align:start position:0% +other component is its projection onto +the orthogonal complement of the plane. + + align:start position:0% +the orthogonal complement of the plane. + + + align:start position:0% +the orthogonal complement of the plane. +in this case onto the normal vector to + + align:start position:0% +in this case onto the normal vector to + + + align:start position:0% +in this case onto the normal vector to +the plane. So in the language of linear + + align:start position:0% +the plane. So in the language of linear + + + align:start position:0% +the plane. So in the language of linear +algebra this is just B equals to its + + align:start position:0% +algebra this is just B equals to its + + + align:start position:0% +algebra this is just B equals to its +projection onto the plane + + align:start position:0% +projection onto the plane + + + align:start position:0% +projection onto the plane +plus its projection I'm going to call it + + align:start position:0% +plus its projection I'm going to call it + + + align:start position:0% +plus its projection I'm going to call it +PN onto the orthogonal complement of the + + align:start position:0% +PN onto the orthogonal complement of the + + + align:start position:0% +PN onto the orthogonal complement of the +plane. Okay, I'm going + + align:start position:0% +plane. Okay, I'm going + + + align:start position:0% +plane. Okay, I'm going +to suggestively write here the identity + + align:start position:0% +to suggestively write here the identity + + + align:start position:0% +to suggestively write here the identity +matrix so that you can immediately read + + align:start position:0% +matrix so that you can immediately read + + + align:start position:0% +matrix so that you can immediately read +off a matrix equality associated with + + align:start position:0% +off a matrix equality associated with + + + align:start position:0% +off a matrix equality associated with +this um equality here. It's the identity + + align:start position:0% +this um equality here. It's the identity + + + align:start position:0% +this um equality here. It's the identity +equals P + + + align:start position:0% +equals P + + + + align:start position:0% +equals P + +N and therefore the projection matrix is + + align:start position:0% +N and therefore the projection matrix is + + + align:start position:0% +N and therefore the projection matrix is +just the identity minus the projection + + align:start position:0% +just the identity minus the projection + + + align:start position:0% +just the identity minus the projection +matrix onto the normal vector. + + align:start position:0% +matrix onto the normal vector. + + + align:start position:0% +matrix onto the normal vector. +Now this object here PN is much easier + + align:start position:0% +Now this object here PN is much easier + + + align:start position:0% +Now this object here PN is much easier +to compute. Well, for two reasons. First + + align:start position:0% +to compute. Well, for two reasons. First + + + align:start position:0% +to compute. Well, for two reasons. First +one is that well projecting onto a + + align:start position:0% +one is that well projecting onto a + + + align:start position:0% +one is that well projecting onto a +one-dimensional subspace is infinitely + + align:start position:0% +one-dimensional subspace is infinitely + + + align:start position:0% +one-dimensional subspace is infinitely +easier than projecting onto a higher + + align:start position:0% +easier than projecting onto a higher + + + align:start position:0% +easier than projecting onto a higher +dimensional subspace. And second + + align:start position:0% +dimensional subspace. And second + + + align:start position:0% +dimensional subspace. And second +um we already have well immediately we + + align:start position:0% +um we already have well immediately we + + + align:start position:0% +um we already have well immediately we +can read off from the equation of the + + align:start position:0% +can read off from the equation of the + + + align:start position:0% +can read off from the equation of the +plane what the normal vector is. So we + + align:start position:0% +plane what the normal vector is. So we + + + align:start position:0% +plane what the normal vector is. So we +don't have to um + + align:start position:0% +don't have to um + + + align:start position:0% +don't have to um +derive these guy like we don't have to + + align:start position:0% +derive these guy like we don't have to + + + align:start position:0% +derive these guy like we don't have to +do what we did here. Um okay. So + + align:start position:0% +do what we did here. Um okay. So + + + align:start position:0% +do what we did here. Um okay. So +uh essentially PN will be + + align:start position:0% +uh essentially PN will be + + + align:start position:0% +uh essentially PN will be +uh + + align:start position:0% +uh + + + align:start position:0% +uh +N transpose N + + align:start position:0% + + + + align:start position:0% + +inverse N transpose. + + align:start position:0% + + + + align:start position:0% + +And that's equal to + + align:start position:0% +And that's equal to + + + align:start position:0% +And that's equal to +um one + + align:start position:0% +um one + + + align:start position:0% +um one +uh + + align:start position:0% + + + + align:start position:0% + +one and n transpose n inverse. This is + + align:start position:0% +one and n transpose n inverse. This is + + + align:start position:0% +one and n transpose n inverse. This is +just a + + align:start position:0% +just a + + + align:start position:0% +just a +number. It's one over the magnitude of + + align:start position:0% +number. It's one over the magnitude of + + + align:start position:0% +number. It's one over the magnitude of +the normal vector. Uh so that's the + + align:start position:0% +the normal vector. Uh so that's the + + + align:start position:0% +the normal vector. Uh so that's the +magnitude squared. So that's three and + + align:start position:0% + + + + align:start position:0% + +one. + + align:start position:0% +one. + + + align:start position:0% +one. +Okay, I'm going + + align:start position:0% +Okay, I'm going + + + align:start position:0% +Okay, I'm going +to + + align:start position:0% + + + + align:start position:0% + +write the answer here. + + align:start position:0% +write the answer here. + + + align:start position:0% +write the answer here. +It's + + align:start position:0% + + + + align:start position:0% + + + align:start position:0% + + + align:start position:0% +one one + + align:start position:0% + + + + align:start position:0% + +um one + + align:start position:0% +um one + + + align:start position:0% +um one +one andative one + + align:start position:0% + + + + align:start position:0% + +one right + + align:start position:0% +one right + + + align:start position:0% +one right +um so + + align:start position:0% +um so + + + align:start position:0% +um so +Yeah. In order and in order to get the + + align:start position:0% +Yeah. In order and in order to get the + + + align:start position:0% +Yeah. In order and in order to get the +projection matrix. + + align:start position:0% +projection matrix. + + + align:start position:0% +projection matrix. +Yes. + + align:start position:0% +Yes. + + + align:start position:0% +Yes. +Oh, thank you. Thank you. And in order + + align:start position:0% +Oh, thank you. Thank you. And in order + + + align:start position:0% +Oh, thank you. Thank you. And in order +to get the projection + + align:start position:0% +to get the projection + + + align:start position:0% +to get the projection +matrix, we just subtract from the + + align:start position:0% +matrix, we just subtract from the + + + align:start position:0% +matrix, we just subtract from the +identity this expression. And you can + + align:start position:0% +identity this expression. And you can + + + align:start position:0% +identity this expression. And you can +confirm that it's this answer. We get + + align:start position:0% +confirm that it's this answer. We get + + + align:start position:0% +confirm that it's this answer. We get +the same answer as here. All right. I + + align:start position:0% +the same answer as here. All right. I + + + align:start position:0% +the same answer as here. All right. I +think we're done here. \ No newline at end of file diff --git a/tei0bSKTyf0.txt b/tei0bSKTyf0.txt new file mode 100644 index 0000000000000000000000000000000000000000..6b91f4cf29aa9256da0804752165d29fb834c69c --- /dev/null +++ b/tei0bSKTyf0.txt @@ -0,0 +1,267 @@ +align:start position:0% + +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +Here's another example, not as dramatic + + align:start position:0% +Here's another example, not as dramatic + + + align:start position:0% +Here's another example, not as dramatic +of uh creating a photo illustration out + + align:start position:0% +of uh creating a photo illustration out + + + align:start position:0% +of uh creating a photo illustration out +of photographs, but in this case, this + + align:start position:0% +of photographs, but in this case, this + + + align:start position:0% +of photographs, but in this case, this +is also showing evidence that you are + + align:start position:0% +is also showing evidence that you are + + + align:start position:0% +is also showing evidence that you are +fabricating the pieces in your device. + + align:start position:0% +fabricating the pieces in your device. + + + align:start position:0% +fabricating the pieces in your device. +This particular image is a CAD image + + align:start position:0% +This particular image is a CAD image + + + align:start position:0% +This particular image is a CAD image +used by the researchers to show their + + align:start position:0% +used by the researchers to show their + + + align:start position:0% +used by the researchers to show their +device showing the various fabrications. + + align:start position:0% +device showing the various fabrications. + + + align:start position:0% +device showing the various fabrications. +And this is how they used it in their + + align:start position:0% +And this is how they used it in their + + + align:start position:0% +And this is how they used it in their +patent submission. But this is done in + + align:start position:0% +patent submission. But this is done in + + + align:start position:0% +patent submission. But this is done in +CAD. They also made a picture of their + + align:start position:0% +CAD. They also made a picture of their + + + align:start position:0% +CAD. They also made a picture of their +device, but you really can't see very + + align:start position:0% +device, but you really can't see very + + + align:start position:0% +device, but you really can't see very +much about their very sophisticated + + align:start position:0% +much about their very sophisticated + + + align:start position:0% +much about their very sophisticated +ability to make the various layers. And + + align:start position:0% +ability to make the various layers. And + + + align:start position:0% +ability to make the various layers. And +so what I did was I took that device and + + align:start position:0% +so what I did was I took that device and + + + align:start position:0% +so what I did was I took that device and +separated into the initial pieces that + + align:start position:0% +separated into the initial pieces that + + + align:start position:0% +separated into the initial pieces that +they did fabricate. I laid them out on a + + align:start position:0% +they did fabricate. I laid them out on a + + + align:start position:0% +they did fabricate. I laid them out on a +background and decided to try to use + + align:start position:0% +background and decided to try to use + + + align:start position:0% +background and decided to try to use +these images showing the layering of how + + align:start position:0% +these images showing the layering of how + + + align:start position:0% +these images showing the layering of how +the device is made. So I out of these + + align:start position:0% +the device is made. So I out of these + + + align:start position:0% +the device is made. So I out of these +images I constructed a photo + + align:start position:0% +images I constructed a photo + + + align:start position:0% +images I constructed a photo +illustration of those pieces using + + align:start position:0% +illustration of those pieces using + + + align:start position:0% +illustration of those pieces using +software but these are real images that + + align:start position:0% +software but these are real images that + + + align:start position:0% +software but these are real images that +you've just seen from before. Here's + + align:start position:0% +you've just seen from before. Here's + + + align:start position:0% +you've just seen from before. Here's +another way of showing it making it + + align:start position:0% +another way of showing it making it + + + align:start position:0% +another way of showing it making it +somewhat + + align:start position:0% +somewhat + + + align:start position:0% +somewhat +three-dimensional. But basically this is + + align:start position:0% +three-dimensional. But basically this is + + + align:start position:0% +three-dimensional. But basically this is +a photo illustration of the layers of + + align:start position:0% +a photo illustration of the layers of + + + align:start position:0% +a photo illustration of the layers of +this device. Not only + + align:start position:0% +this device. Not only + + + align:start position:0% +this device. Not only +showing how it works with the right + + align:start position:0% +showing how it works with the right + + + align:start position:0% +showing how it works with the right +labeling, of course, but also showing + + align:start position:0% +labeling, of course, but also showing + + + align:start position:0% +labeling, of course, but also showing +that they did indeed fabricate the + + align:start position:0% +that they did indeed fabricate the + + + align:start position:0% +that they did indeed fabricate the +layers. \ No newline at end of file diff --git a/uBRdfsz_YB4.txt b/uBRdfsz_YB4.txt new file mode 100644 index 0000000000000000000000000000000000000000..a5e94cfc0cef914dace393a435a8e27ad1bc1678 --- /dev/null +++ b/uBRdfsz_YB4.txt @@ -0,0 +1,787 @@ +PROFESSOR: Good morning. + +Come on down. + +All right. + +So last time, we talked about +the first couple of steps of + +the central dogma. + +The central dogma is this name +given to the statement DNA + +goes to DNA by replication. + +DNA goes to RNA by the process +of transcription. + +We call it transcription because +it's such a direct + +copying of letter to letter. + +RNA goes to protein by a +process of translation, + +because translation is the +kind of word we would use + +between two different +languages. + +And there are two different +languages-- + +the languages of nucleotides +and the + +language of amino acids. + +For what it's worth, it's name, +the central dogma, goes + +back to Francis Crick, who +called this the central dogma. + +He did it in a kind of a +light-hearted way, although + +others since then have +criticized it, saying, oh, + +this is dogmatic. + +Actually, Crick said not +that DNA goes to + +RNA goes to the protein. + +He says that all information +flows from nucleic acids to + +proteins and not back again. + +Because even then, Crick knew +that in theory, there was no + +reason you couldn't go back from +RNA to DNA, and as we'll + +see today, that happens. + +So sometimes people say, oh, +well, the central dogma was + +proved wrong because RNA +can go back to DNA. + +Well, actually, that was even +anticipated right then at the + +very beginning, when they +realized RNA and DNA were + +essentially equivalent +information. + +The key step of converting +nucleic acid information into + +protein information +is translation. + +And that's the last bit +we have to fill in + +and talk about today. + +So let me start by just +reminding you-- because most + +of you know it-- + +how translation works. + +So, in translation, you have a +particular RNA that has been + +made by the cell. + +Here's my RNA. + +It goes five prime +to three prime. + +That's always the way we +write these things. + +And it has some particular +sequence. + +I'll make up a sequence here. + +A, U, A, C, G, A, U, G, A, A, +G, A, G, G, C, C, C, dot dot + +dot dot dot, U, A, G, dot dot +dot dot, three prime. + +All right. + +Somehow, that's going to be +translated into a protein. + +It's translated according to a +fantastic look-up up table. + +This look-up table is called +the genetic code. + +And the rule, the algorithm-- + +and it's a fairly simple +algorithm, well, nothing's + +ever really simple in biology, +but it's close to simple-- + +is you run along the sequence +from the beginning. + +And you guys could write this. + +Anybody who's taken basic +computer programming. + +Run along the sequence and find +the first occurrence of + +A, U, G. Why A, U, G? + +Because A, U, G is the +place you start. + +That's how life worked it out, +and that's what it does. + +After that, you parse the +sequence in triplets. + +These triplets get +the name codons. + +And then you keep going +until you hit one of + +three possible triplets. + +U, A, G. U, A, A. U, G, +A. And you stop there. + +Any MIT student should be able +to write an algorithm that + +takes a string, finds the first +occurrence of U, A, G, + +breaks it up into triplets +passed there, keeps going + +until you encounter one of +these three triplets. + +What do you do for +a given triplet? + +You look it up against +the table. + +How many triplets are there? + +How many three-letter words +are there with the four + +nucleotides? + +AUDIENCE: 64. + +PROFESSOR: It's 4 to the 3rd-- + +64 possible words. + +I've used up three of them to be +stop, so there are 4 to the + +3rd possible codons. + +That's 64. + +Three stops. + +The other 61 possible codons +specify an amino acid. + +That's it. + +There's a look-up table. + +The genetic code. + +How many amino acids +are there? + +20. + +And there are 61 possible +codons, so that implies there + +is some redundancy. + +Some codons-- + +some amino acids are coded +for by the same codon. + +Okay. + +That's fine. + +And in your book is the genetic +code that is the + +look-up table here. + +The genetic code translates +these codons into amino acids. + +Or to stop, in the case of +the three stop signals. + +So for example, this A, U, +G at the front is always + +translated into methionine. + +Met. + +And if I've got it right, +this should be a lysine. + +Here we go. + +Arginine, proline, et cetera-- +you just look it up. + +That's it. + +That's the order in which +you make the proteins. + +So you send off an order written +in RNA, you send it + +off to the factory, the factory +sends you back a + +protein that is methionine, +lysine, arginine, proline, + +blah, blah, blah, blah, blah. + +That's it. + +This genetic code is essentially +universal amongst + +all of life. + +That's pretty stunning. + +What does that tell you? + +The fact that all of life uses +virtually the identical + +genetic code? + +There's actually a tiny +difference between prokaryotes + +and eukaryotes affecting a +codon and there's a tiny + +difference somewhere else. + +But essentially, it's the exact +same genetic code that + +all of life uses. + +It's very unlikely that this +genetic code is the only + +possible way you could make +a genetic code, right? + +So the fact that all of life +uses, essentially, exactly the + +same code is pretty strong +evidence that all currently + +existing life descends from +a common ancestor. + +Because if these were evolved +independently, it's extremely + +unlikely that you would have +gotten exactly the same + +genetic code. + +So that's an interesting point +that you can see from just the + +fact that everybody uses +essentially the + +same genetic code. + +It's a universal genetic code. + +All right. + +So I've expressed this to you +in a completely computer + +sciencey kind of way. + +But, of course, the cell doesn't +do this by computer + +science because cells are +unable to write C code. + +The reason that cells are unable +to write C code is C + +wasn't really developed until +the last several decades, and + +cells, pretty sure, precede the +development of C code by + +Kernighan and Ritchie. + +So it's got to be the case that +it's done some other way. + +How is it done? + +Well, it's done like this. + +And I'll just be very +schematic and you'll + +get it in your book. + +There's a big machine. + +The big machine here is +called the ribosome. + +It consists, itself, of proteins +and RNAs, and it's a + +huge structure. + +The huge structure needs +to read codons. + +And this is a case where +Francis Crick + +drove everybody nuts. + +Francis Crick, back in the +1950s, just sat at his desk + +and thought. + +He was terrible at doing +experiments-- + +nobody really wanted to let +him do experiments. + +Francis was a great thinker. + +He thought. + +He said, golly, how can this +sequence be translated into + +amino acids? + +Well, people at the time had +all sorts of nutty ideas. + +Some of the nutty ideas was that +the sequence of the RNA + +folded up into pockets that +just fit a proline. + +And another pocket that +just an arginine. + +And if you just think about the +constraints to get that to + +work, it's nuts. + +That the sequence itself would +form perfect binding pockets + +for the necessary amino acids. + +Crick said impossible. + +He said the really sensible +way to do this, if I were + +running life, what I +would do is I would + +have an adapter molecule. + +The adapter molecule would be +some kind of a nucleic acid, + +and the nucleic acid would kind +of match the codon on one + +end and have the amino acid +on the other end. + +And then there'd be another +adapter, and the adapter would + +have the next amino acid. + +And then you would catalyze +a bond between them. + +Therefore, I predict, says +Francis, there will be small + +adapter molecules, probably made +out of RNAs themselves. + +And Francis called this the +Adapter Hypothesis. + +It drove people crazy because, +of course, he was right. + +People found the adapters and +they would use transfer things + +that transfer information-- + +get called transfer RNAs. + +What happens is the ribosome +has pockets in which these + +transfer RNAs basically come +in, match their sequence, + +there's a codon each of these +transfer RNAs has a matching + +anticodon that matches the +triplet, and it has already + +attached to it an amino acid-- + +the right amino acid +for that anticodon. + +How does that right amino +acid get attached + +to the right tRNA? + +There's an enzyme. + +The job of that enzyme is to +attach this amino acid, + +proline, to this transfer RNA. + +It's a Prolyl-tRNA synthetase. + +And its job is to put proline +on the right tRNAs. + +There's another one that puts +arginine on the right tRNAs. + +There's a whole business that's +set up to get the right + +tRNAs, have the right amino +acids attached to them through + +a bunch of enzymes +floating around. + +So then these tRNAs with the +amino acid attached drop in, + +they drop into the next +position, and a bond-- + +the peptide bond-- +is catalyzed. + +Interesting factoid. + +The catalysis, this enzymatic +catalysis to join together + +those amino acids is actually +carried out not by the + +proteins in a ribosome, +but actually + +by RNA in the ribosome. + +The RNA is the enzyme. + +You know why that's +kind of cool? + +If this bothers you, just forget +it, but one of the + +mysteries about how you ever go +from DNA to RNA to protein + +and all of that is how the whole +thing ever got started. + +How could you possibly have +gotten protein synthesis + +started if the things that were +needed to make protein + +synthesis were proteins? + +So this is actually an echo of +an ancient world 3 billion + +years ago, where this was all +probably carried out by RNAs. + +RNA was probably the early +catalysts for most things, and + +we still see evidence of the +fact that even today your + +peptide bonds are catalyzed +actually by RNA and they're + +doing the enzymatic work. + +Anyway, it's kind of cool. + +If you didn't get that, don't +worry about it, but + +it's kind of cool. + +So then what happens after +you attach the + +first two amino acids? + +Well, the ribosome chugs down +here and grabs the next code-- + +these two shift over. + +You can either think about the +ribosome moving this way or + +the RNA moving that way. + +The next tRNA drops in, the +next bond gets made, chugs + +over, the next one drops in, +the next one gets made, and + +onward like that until it hits +a stop codon at which, it + +releases it. + +The ribosome knows +to release it. + +There's actually a little factor +that drops in and tells + +it to release it there. + +And that's how you +make proteins-- + +kind of cool. + +It works very well. + +It chugs along in +that fashion. + +For you computer scientists, +what you basically have is a + +two-tape turing machine-- + +you're reading one tape and +writing to the other tape. + +There's a nucleic acid +tape and there's + +an amino acid tape. + +If you're not a computer +scientist, forget I said that. + +OK. + +So it's basically a two-tape +tape turing machine where the + +RNA is coming through here and +the protein is coming out that + +way, but the amino acids +attach to each other + +until it comes off. + +In fact, actually, very +recently, a Nobel Prize was + +awarded last year for beautiful, +beautiful work on + +how this actually takes place-- +the molecular details + +of the ribosome. + +Really gorgeous. + +Any questions about that? + +Yeah. + +AUDIENCE: Is that not +susceptible to the same error + +as replication is? + +PROFESSOR: Oh, is that not +susceptible to the same error? + +Does the ribosome ever +make mistakes? + +It does. + +What happens if you make +the wrong protein? + +AUDIENCE: [INAUDIBLE]. + +PROFESSOR: Oh well. + +The answer turns out to be "oh +well" because for any given + +DNA, you make lots of RNAs. + +For any RNA, you use it +again and again to + +make lots of proteins. + +And if the occasional protein is +not so good, if the quality + +control is not perfect, it's +much less serious than if your + +master instructions in the +DNA were not perfect. + +So the cell actually +devotes a lot less + +attention to quality control. + +Now. + +That's not to say there isn't +important quality control. + +There are quality control +mechanisms, but it doesn't + +have to be as accurate as one +error in a billion, like you + +want to be in copying +your DNA. + +And that's really an important +point, is the archival copy + +has to be really good, but +little yellow sticky notes-- + +what you make from it, which +are basically RNA or the + +little yellow sticky notes you +copied down-- they don't have + +to be perfect. + +And each copy, the protein +doesn't have to be-- + +and if the protein is not +perfect, there are mechanisms + +that take unfolded proteins +and degrade them. + +So it turns out there are ways +to achieve quality control in + +that sense. + +It's a great question. \ No newline at end of file diff --git a/uDXH6Uu0ghc.txt b/uDXH6Uu0ghc.txt new file mode 100644 index 0000000000000000000000000000000000000000..2f26a1db3454a972fb88ddbb19db6bd6733b8231 --- /dev/null +++ b/uDXH6Uu0ghc.txt @@ -0,0 +1,489 @@ +The following content is +provided under a Creative + +Commons license. + +Your support will help MIT +OpenCourseWare continue to + +offer high quality educational +resources for free. + +To make a donation or view +additional materials from + +hundreds of MIT courses, visit +MIT OpenCourseWare at + +ocw.mit.edu. + +PROFESSOR: Good morning. + +AUDIENCE: Good morning. + +PROFESSOR: All right. + +So today-- + +I haven't seen you in a while. + +Anyway, today, we're going to +turn back to our picture, + +function gene protein. + +We filled in genetics. + +We filled in biochemistry. + +We've now got the connection +between gene and protein + +through molecular biology. + +We know gene encodes protein. + +We know central dogma, +DNA goes to the + +RNA goes to the protein. + +We know all that in theory. + +In fact, people knew this by +the middle of the 1960s. + +People were so excited that they +understood the idea of + +how genes give rise to proteins +through transcription + +and translation, they read the +genetic code, that they + +declared victory. + +Some of them said, done with +the secret of life. + +Let's go on and do the brain. + +That was actually the thinking +of a lot of the great + +molecular biologists +in the late 1960s. + +Let's go do the brain. + +Why did they say such a thing? + +Well, because they +thought they were + +done with the problem. + +They thought that once you knew +in principle how a gene + +gave rise to a protein, +you could do it. + +But in practice, nobody could +read a single gene. + +Nobody could even identify +a single gene. + +Maybe that's why they went on +to say, let's go study the + +brain, because they actually +weren't sure what they could + +do past that point. + +All right. + +So wait a second, +wait a second. + +I said nobody could even +purify a single gene. + +Didn't we talk about purifying +the genetic material? + +You're supposed to say +yes at that point. + +Yes, right? + +We talked about that. + +Avery, McCarty, MacLeod-- we +purified the genetic material. + +We did it by using this +assay of transforming. + +So what do I mean by we can't +purify a single gene? + +What I mean is that we can +purify the hereditary material + +away from everything else, but +we get all of it together. + +We don't get individual genes +separated from each other. + +We get the whole mixture +of all the genes, + +all the genetic material. + +As a biochemist, how are we +going to ever separate the + +gene encoding-- + +oh I don't know, ARG1, our +favorite gene for arginine + +biosynthesis-- + +from the gene encoding +ARG2, for example? + +What kind of biochemistry +can we do to + +separate these two genes? + +Do they have different +biochemical properties? + +What's so different about +ARG1 and ARG2? + +What's their different +biochemical properties? + +They're both DNA. + +They have exactly the same +building blocks, slightly + +different order. + +You think you have a +purification procedure, I'm + +going to run it over some column +and separate it by + +something that's going to +separate ARG1 from ARG2? + +No. + +From the point of view of a +pure biochemist, they look + +exactly the same. + +All the different genes have +the same biochemical + +properties. + +How in the world would we ever +purify ARG1 from ARG2, or in + +the human, the gene encoding +hemoglobin from the gene + +encoding collagen from the gene +encoding keratin from the + +gene encoding anything else? + +Think about it. + +That's a tough problem. + +There is a brilliant solution +that arose in the 1970s to how + +we could purify the individual +genes away from each other. + +But it's like no other piece +of biochemistry anybody had + +ever seen before. + +It has a totally different +principle behind it. + +Because it isn't just +fractionating things according + +to their biochemical +properties. + +It involves something else. + +And it's called cloning. + +It is called cloning. + +Molecular cloning. + +You see, the problem is this. + +The human genome-- + +how big is the human genome? + +How many bases? + +Three billion bases, three +times 10 to the + +ninth bases, right? + +How big is a typical +human gene? + +A typical human gene might +be 30,000 bases. + +How big is a typical mutation +that we might want to find in + +a typical gene, like causing +sickle cell anemia? + +One base. + +We've got to purify out genes +that are one part in 10 to the + +fifth and mutations that +are one part in 10 to + +the ninth or so. + +And how are we going +to do that? + +Well, the trick is this. + +I'll give you the quick +overview, and then we'll spend + +today looking at it. + +Step one is we cut up our DNA. + +We cut DNA at defined sites, and +we then paste the DNA to + +distinct molecules +called vectors. + +These vectors have a cool +property, that when you take a + +vector and you insert in it a +piece of DNA, that vector is + +able to grow in another +organism. + +You then transform the DNA-- + +that's transfer, we use the +word transform the DNA-- + +into something like E. coli, +where you get your little + +vector in there. + +It grows within E. coli, and as +E. coli divides, it makes + +copies of itself. + +And then you select those +bacteria that have received, + +that have been transformed, grow +them up on a petri plate + +so that you have little +colonies. + +And then you screen +the colonies. + +Now, what do I mean? + +We cut the DNA. + +We paste the DNA. + +We transform the DNA. + +We select the bacteria that +have been successfully + +transformed. + +And we screen the resulting +colonies to find what we're + +looking for. + +Now, notice-- + +that amazing trick here is when +we cut up the DNA into + +single molecules, lots and lots +of single molecules, and + +we paste them into vectors, +and we transform them into + +bacteria, each one of those +bacteria gets exactly one + +molecule, give or take. + +It gets one piece +of human DNA. + +We then spread them out on a +plate and they grow up, and + +each one grows up +copies for us of + +individual pieces of DNA. + +That is so cool. + +Because we've just accomplished +biochemical + +purification. + +It's not based on any different +properties of the + +individual molecules. + +It's based on the fact that +we dilute them, in effect. + +They're diluted, and +one molecule + +ends up in each bacteria. + +So they're purified +in that sense. + +And then when that bacteria +grows up, everything it grows + +up is a pure copy, a copy of +that single piece of DNA that + +went into it. + +That's a different kind +of purification. + +When I'm done-- and we'll go +through this whole process. + +That's the point of today's +lecture, is to go through the + +whole process. + +When I'm done, I have +bacteria spread out. + +And right over there, one of +these guys has ARG1, and one + +of these guys has ARG2, and one +of these guys has ARG10. + +Now, admittedly, I don't know +which one has which, but I've + +accomplished the purification. + +I'll then have to figure out +how to screen and find out + +which one is which, but I have +separated the molecules away + +from each other by this process +of cloning, diluting + +them in a way-- + +one molecule per bacteria-- + +and growing them back up. + +I could do this for anything. + +I could dilute proteins down +into test tubes that had one + +protein molecule per test tube, +and I could say I've + +accomplished purification. + +The problem with it is I have +no way to replicate those + +proteins to get a meaningful +amount of it. + +But when it's DNA, and I've put +it back into a bacteria, I + +have a way to grow it back up. + +And that's why this +trick works-- + +is because DNA is a molecule +that can replicate. + +No other molecule has +that cool property. + +And so you can pull +this off for DNA. + +All right. + +Now we have to dive in to +understand how this could + +possibly work. \ No newline at end of file diff --git a/uhjq0UQqkVg.txt b/uhjq0UQqkVg.txt new file mode 100644 index 0000000000000000000000000000000000000000..593c0a516cc83b0aa4bb39a9ac134b566e3018b3 --- /dev/null +++ b/uhjq0UQqkVg.txt @@ -0,0 +1,15803 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a creative commons license your support + + align:start position:0% +a creative commons license your support + + + align:start position:0% +a creative commons license your support +will help mit opencourseware continue to + + align:start position:0% +will help mit opencourseware continue to + + + align:start position:0% +will help mit opencourseware continue to +offer high quality educational resources + + align:start position:0% +offer high quality educational resources + + + align:start position:0% +offer high quality educational resources +for free + + align:start position:0% +for free + + + align:start position:0% +for free +to make a donation or to view additional + + align:start position:0% +to make a donation or to view additional + + + align:start position:0% +to make a donation or to view additional +materials from hundreds of mit courses + + align:start position:0% +materials from hundreds of mit courses + + + align:start position:0% +materials from hundreds of mit courses +visit mit opencourseware at ocw.mit.edu + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +in the last class this is what we did + + align:start position:0% + + + + align:start position:0% + +first we did torque we + + align:start position:0% +first we did torque we + + + align:start position:0% +first we did torque we +we uh define torque + + align:start position:0% + + + + align:start position:0% + +and torque + + align:start position:0% +and torque + + + align:start position:0% +and torque +of a force on a particle don't look at + + align:start position:0% +of a force on a particle don't look at + + + align:start position:0% +of a force on a particle don't look at +that look at this + + align:start position:0% +that look at this + + + align:start position:0% +that look at this +the torque on a for of a force + + align:start position:0% +the torque on a for of a force + + + align:start position:0% +the torque on a for of a force +on a particle is equal to tau + + align:start position:0% +on a particle is equal to tau + + + align:start position:0% +on a particle is equal to tau +it's a vector little tau + + align:start position:0% +it's a vector little tau + + + align:start position:0% +it's a vector little tau +on the particle p about point q + + align:start position:0% +on the particle p about point q + + + align:start position:0% +on the particle p about point q +is equal to + + align:start position:0% + + + + align:start position:0% + +you know this but + + align:start position:0% +you know this but + + + align:start position:0% +you know this but +cross + + align:start position:0% +cross + + + align:start position:0% +cross +the force on the particle p + + align:start position:0% +the force on the particle p + + + align:start position:0% +the force on the particle p +you can pick any q you want + + align:start position:0% +you can pick any q you want + + + align:start position:0% +you can pick any q you want +the second thing we did was angular + + align:start position:0% +the second thing we did was angular + + + align:start position:0% +the second thing we did was angular +momentum + + align:start position:0% + + + + align:start position:0% + +thanks aj + + align:start position:0% +thanks aj + + + align:start position:0% +thanks aj +okay the second thing that's just + + align:start position:0% +okay the second thing that's just + + + align:start position:0% +okay the second thing that's just +recreating stuff we did in the last + + align:start position:0% +recreating stuff we did in the last + + + align:start position:0% +recreating stuff we did in the last +class don't worry i just i just want to + + align:start position:0% +class don't worry i just i just want to + + + align:start position:0% +class don't worry i just i just want to +save some insight i want to give you + + align:start position:0% +save some insight i want to give you + + + align:start position:0% +save some insight i want to give you +some context don't worry about it we'll + + align:start position:0% +some context don't worry about it we'll + + + align:start position:0% +some context don't worry about it we'll +get there + + align:start position:0% +get there + + + align:start position:0% +get there +okay angular momentum we defined it as + + align:start position:0% +okay angular momentum we defined it as + + + align:start position:0% +okay angular momentum we defined it as +we called it a with respect to frame a + + align:start position:0% +we called it a with respect to frame a + + + align:start position:0% +we called it a with respect to frame a +h is angle momentum because angular + + align:start position:0% +h is angle momentum because angular + + + align:start position:0% +h is angle momentum because angular +momentum is + + align:start position:0% +momentum is + + + align:start position:0% +momentum is +really angular momentum that's where it + + align:start position:0% +really angular momentum that's where it + + + align:start position:0% +really angular momentum that's where it +comes from + + align:start position:0% + + + + align:start position:0% + +the h is silent + + align:start position:0% +the h is silent + + + align:start position:0% +the h is silent +i'm joking you know that + + align:start position:0% +i'm joking you know that + + + align:start position:0% +i'm joking you know that +thank you + + align:start position:0% + + + + align:start position:0% + +is equal to r + + align:start position:0% +is equal to r + + + align:start position:0% +is equal to r +qp + + align:start position:0% + + + + align:start position:0% + +cross + + align:start position:0% + + + + align:start position:0% + +a + + align:start position:0% +a + + + align:start position:0% +a +p + + align:start position:0% +p + + + align:start position:0% +p +of p + + align:start position:0% +of p + + + align:start position:0% +of p +right so all this is you know for a + + align:start position:0% +right so all this is you know for a + + + align:start position:0% +right so all this is you know for a +particle + + align:start position:0% +particle + + + align:start position:0% +particle +this is o this is q is the reference + + align:start position:0% +this is o this is q is the reference + + + align:start position:0% +this is o this is q is the reference +point + + align:start position:0% +point + + + align:start position:0% +point +this is a particle p + + align:start position:0% +this is a particle p + + + align:start position:0% +this is a particle p +right and there's a force on it + + align:start position:0% +right and there's a force on it + + + align:start position:0% +right and there's a force on it +right this is for that can this is for + + align:start position:0% +right this is for that can this is for + + + align:start position:0% +right this is for that can this is for +that situation + + align:start position:0% +that situation + + + align:start position:0% +that situation +little p of course is the momentum + + align:start position:0% +little p of course is the momentum + + + align:start position:0% +little p of course is the momentum +linear momentum take the cross product + + align:start position:0% +linear momentum take the cross product + + + align:start position:0% +linear momentum take the cross product +with r to get angular momentum + + align:start position:0% +with r to get angular momentum + + + align:start position:0% +with r to get angular momentum +and then finally we said that + + align:start position:0% +and then finally we said that + + + align:start position:0% +and then finally we said that +torque + + align:start position:0% +torque + + + align:start position:0% +torque +kind of the equivalent of f is equal to + + align:start position:0% +kind of the equivalent of f is equal to + + + align:start position:0% +kind of the equivalent of f is equal to +m a for rotation + + align:start position:0% +m a for rotation + + + align:start position:0% +m a for rotation +is this + + align:start position:0% +is this + + + align:start position:0% +is this +torque + + align:start position:0% + + + + align:start position:0% + +p over q + + align:start position:0% +p over q + + + align:start position:0% +p over q +sorry p uh let's just pick a q + + align:start position:0% +sorry p uh let's just pick a q + + + align:start position:0% +sorry p uh let's just pick a q +is equal to + + align:start position:0% +is equal to + + + align:start position:0% +is equal to +a + + align:start position:0% +a + + + align:start position:0% +a +d by dt + + align:start position:0% + + + + align:start position:0% + +a + + align:start position:0% +a + + + align:start position:0% +a +angular momentum + + align:start position:0% +angular momentum + + + align:start position:0% +angular momentum +right rate of change of angular momentum + + align:start position:0% +right rate of change of angular momentum + + + align:start position:0% +right rate of change of angular momentum +is that strictly correct + + align:start position:0% + + + + align:start position:0% + +is that correct + + align:start position:0% + + + + align:start position:0% + +so that's only true in some special + + align:start position:0% +so that's only true in some special + + + align:start position:0% +so that's only true in some special +cases the real complete formula + + align:start position:0% +cases the real complete formula + + + align:start position:0% +cases the real complete formula +is there's this + + align:start position:0% +is there's this + + + align:start position:0% +is there's this +correction term + + align:start position:0% +correction term + + + align:start position:0% +correction term +which again has no name so i called it + + align:start position:0% +which again has no name so i called it + + + align:start position:0% +which again has no name so i called it +the pesky term which is because i need + + align:start position:0% +the pesky term which is because i need + + + align:start position:0% +the pesky term which is because i need +to refer to it and i need a name for it + + align:start position:0% +to refer to it and i need a name for it + + + align:start position:0% +to refer to it and i need a name for it +is a v + + align:start position:0% +is a v + + + align:start position:0% +is a v +p sorry avq a bigger pattern + + align:start position:0% +p sorry avq a bigger pattern + + + align:start position:0% +p sorry avq a bigger pattern +cross + + align:start position:0% +cross + + + align:start position:0% +cross +a + + align:start position:0% +a + + + align:start position:0% +a +p + + align:start position:0% +p + + + align:start position:0% +p +p + + align:start position:0% + + + + align:start position:0% + +and we call this the pesky term + + align:start position:0% + + + + align:start position:0% + +okay so that's the three things we did + + align:start position:0% +okay so that's the three things we did + + + align:start position:0% +okay so that's the three things we did +yesterday i mean on in the last class + + align:start position:0% +yesterday i mean on in the last class + + + align:start position:0% +yesterday i mean on in the last class +torque angular momentum + + align:start position:0% +torque angular momentum + + + align:start position:0% +torque angular momentum +and torque related to angular momentum + + align:start position:0% +and torque related to angular momentum + + + align:start position:0% +and torque related to angular momentum +right two definitions these two are + + align:start position:0% +right two definitions these two are + + + align:start position:0% +right two definitions these two are +definitions + + align:start position:0% +definitions + + + align:start position:0% +definitions +and this is a + + align:start position:0% +and this is a + + + align:start position:0% +and this is a +a law which comes from f is equal to m a + + align:start position:0% +a law which comes from f is equal to m a + + + align:start position:0% +a law which comes from f is equal to m a +all right + + align:start position:0% +all right + + + align:start position:0% +all right +and then the other thing we did in the + + align:start position:0% +and then the other thing we did in the + + + align:start position:0% +and then the other thing we did in the +last class + + align:start position:0% +last class + + + align:start position:0% +last class +was we started the dumbbell problem + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +now + + align:start position:0% +now + + + align:start position:0% +now +all this was for a single point + + align:start position:0% +all this was for a single point + + + align:start position:0% +all this was for a single point +no rigid body is a single particle right + + align:start position:0% +no rigid body is a single particle right + + + align:start position:0% +no rigid body is a single particle right +which is a point mass + + align:start position:0% +which is a point mass + + + align:start position:0% +which is a point mass +the dumbbell problem + + align:start position:0% +the dumbbell problem + + + align:start position:0% +the dumbbell problem +was + + align:start position:0% +was + + + align:start position:0% +was +two point passes connected with the link + + align:start position:0% +two point passes connected with the link + + + align:start position:0% +two point passes connected with the link +remember that + + align:start position:0% +remember that + + + align:start position:0% +remember that +but i said look a physical ma + + align:start position:0% +but i said look a physical ma + + + align:start position:0% +but i said look a physical ma +assume some unknown forces + + align:start position:0% +assume some unknown forces + + + align:start position:0% +assume some unknown forces +in the link and we'll just solve it like + + align:start position:0% +in the link and we'll just solve it like + + + align:start position:0% +in the link and we'll just solve it like +it's + + align:start position:0% +it's + + + align:start position:0% +it's +two one particles + + align:start position:0% +two one particles + + + align:start position:0% +two one particles +right + + align:start position:0% +right + + + align:start position:0% +right +and we should be able to handle two + + align:start position:0% +and we should be able to handle two + + + align:start position:0% +and we should be able to handle two +particles everything that follows in + + align:start position:0% +particles everything that follows in + + + align:start position:0% +particles everything that follows in +this course we should be able to solve + + align:start position:0% +this course we should be able to solve + + + align:start position:0% +this course we should be able to solve +with f is equal to m a + + align:start position:0% +with f is equal to m a + + + align:start position:0% +with f is equal to m a +so we started that we didn't finish it + + align:start position:0% +so we started that we didn't finish it + + + align:start position:0% +so we started that we didn't finish it +so i'm going to finish that today and + + align:start position:0% +so i'm going to finish that today and + + + align:start position:0% +so i'm going to finish that today and +that's what rj has written + + align:start position:0% +that's what rj has written + + + align:start position:0% +that's what rj has written +up for me on the right hand side i'll go + + align:start position:0% +up for me on the right hand side i'll go + + + align:start position:0% +up for me on the right hand side i'll go +finish it right there's a lot of stuff + + align:start position:0% +finish it right there's a lot of stuff + + + align:start position:0% +finish it right there's a lot of stuff +we've already done and he's going to + + align:start position:0% +we've already done and he's going to + + + align:start position:0% +we've already done and he's going to +save me some writing + + align:start position:0% + + + + align:start position:0% + +then the next thing we'll do today and + + align:start position:0% +then the next thing we'll do today and + + + align:start position:0% +then the next thing we'll do today and +when you when you're done with the + + align:start position:0% +when you when you're done with the + + + align:start position:0% +when you when you're done with the +dumbbell problem + + align:start position:0% +dumbbell problem + + + align:start position:0% +dumbbell problem +you'll be like well listen i saw the + + align:start position:0% +you'll be like well listen i saw the + + + align:start position:0% +you'll be like well listen i saw the +dumbbell like it was two single + + align:start position:0% +dumbbell like it was two single + + + align:start position:0% +dumbbell like it was two single +particles + + align:start position:0% +particles + + + align:start position:0% +particles +but really i solved a rigid body problem + + align:start position:0% +but really i solved a rigid body problem + + + align:start position:0% +but really i solved a rigid body problem +because it's actually a rigid body right + + align:start position:0% +because it's actually a rigid body right + + + align:start position:0% +because it's actually a rigid body right +and you'll see moment of inertia just + + align:start position:0% +and you'll see moment of inertia just + + + align:start position:0% +and you'll see moment of inertia just +kind of drop out magically + + align:start position:0% +kind of drop out magically + + + align:start position:0% +kind of drop out magically +and then you'll be like huh moment of + + align:start position:0% +and then you'll be like huh moment of + + + align:start position:0% +and then you'll be like huh moment of +inertia is therefore + + align:start position:0% +inertia is therefore + + + align:start position:0% +inertia is therefore +comes naturally when you solve multiple + + align:start position:0% +comes naturally when you solve multiple + + + align:start position:0% +comes naturally when you solve multiple +particle problems right + + align:start position:0% +particle problems right + + + align:start position:0% +particle problems right +so then what we'll do + + align:start position:0% +so then what we'll do + + + align:start position:0% +so then what we'll do +is we will actually formally define + + align:start position:0% +is we will actually formally define + + + align:start position:0% +is we will actually formally define +a + + align:start position:0% +a + + + align:start position:0% +a +moment of inertia and formally introduce + + align:start position:0% +moment of inertia and formally introduce + + + align:start position:0% +moment of inertia and formally introduce +you to torque is equal to i alpha that + + align:start position:0% +you to torque is equal to i alpha that + + + align:start position:0% +you to torque is equal to i alpha that +equation + + align:start position:0% +equation + + + align:start position:0% +equation +all right + + align:start position:0% +all right + + + align:start position:0% +all right +it'll actually come out of this you'll + + align:start position:0% +it'll actually come out of this you'll + + + align:start position:0% +it'll actually come out of this you'll +see torque is good i alpha but you'll + + align:start position:0% +see torque is good i alpha but you'll + + + align:start position:0% +see torque is good i alpha but you'll +see it here right so you'll see torque + + align:start position:0% + + + + align:start position:0% + +is equal to i alpha you'll see that so + + align:start position:0% +is equal to i alpha you'll see that so + + + align:start position:0% +is equal to i alpha you'll see that so +that's kind of what we're going to do + + align:start position:0% +that's kind of what we're going to do + + + align:start position:0% +that's kind of what we're going to do +today + + align:start position:0% +today + + + align:start position:0% +today +any questions + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so if you remember the dumbbell problem + + align:start position:0% +so if you remember the dumbbell problem + + + align:start position:0% +so if you remember the dumbbell problem +what we had was two number a dumbbell + + align:start position:0% +what we had was two number a dumbbell + + + align:start position:0% +what we had was two number a dumbbell +which is two point masses + + align:start position:0% +which is two point masses + + + align:start position:0% +which is two point masses +right + + align:start position:0% +right + + + align:start position:0% +right +and uh we applied two forces f p and f q + + align:start position:0% +and uh we applied two forces f p and f q + + + align:start position:0% +and uh we applied two forces f p and f q +the unequal forces were just to make the + + align:start position:0% +the unequal forces were just to make the + + + align:start position:0% +the unequal forces were just to make the +math easy we made them parallel i don't + + align:start position:0% +math easy we made them parallel i don't + + + align:start position:0% +math easy we made them parallel i don't +care it really doesn't matter which you + + align:start position:0% +care it really doesn't matter which you + + + align:start position:0% +care it really doesn't matter which you +can solve the problem anyway + + align:start position:0% +can solve the problem anyway + + + align:start position:0% +can solve the problem anyway +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and we said that the for the reference + + align:start position:0% +and we said that the for the reference + + + align:start position:0% +and we said that the for the reference +frame a is inertial + + align:start position:0% +frame a is inertial + + + align:start position:0% +frame a is inertial +right + + align:start position:0% +right + + + align:start position:0% +right +the origin is o we call the center of + + align:start position:0% +the origin is o we call the center of + + + align:start position:0% +the origin is o we call the center of +the two dumbbells c + + align:start position:0% +the two dumbbells c + + + align:start position:0% +the two dumbbells c +of the two sorry point masses right the + + align:start position:0% +of the two sorry point masses right the + + + align:start position:0% +of the two sorry point masses right the +center of the dumbbell c + + align:start position:0% +center of the dumbbell c + + + align:start position:0% +center of the dumbbell c +this is q and that is p + + align:start position:0% +this is q and that is p + + + align:start position:0% +this is q and that is p +we pick these + + align:start position:0% +we pick these + + + align:start position:0% +we pick these +non-standard coordinates because they + + align:start position:0% +non-standard coordinates because they + + + align:start position:0% +non-standard coordinates because they +are + + align:start position:0% +are + + + align:start position:0% +are +convenient + + align:start position:0% +convenient + + + align:start position:0% +convenient +they're minimal + + align:start position:0% +they're minimal + + + align:start position:0% +they're minimal +right because this thing has three + + align:start position:0% +right because this thing has three + + + align:start position:0% +right because this thing has three +degrees of freedom + + align:start position:0% +degrees of freedom + + + align:start position:0% +degrees of freedom +and now you have + + align:start position:0% +and now you have + + + align:start position:0% +and now you have +you can take these two + + align:start position:0% +you can take these two + + + align:start position:0% +you can take these two +lengths and the and we we picked theta + + align:start position:0% +lengths and the and we we picked theta + + + align:start position:0% +lengths and the and we we picked theta +as the other non-standard coordinate + + align:start position:0% +as the other non-standard coordinate + + + align:start position:0% +as the other non-standard coordinate +yep + + align:start position:0% +yep + + + align:start position:0% +yep +oh you missed bix p and q + + align:start position:0% + + + + align:start position:0% + +are you sure + + align:start position:0% +are you sure + + + align:start position:0% +are you sure +okay + + align:start position:0% +okay + + + align:start position:0% +okay +okay + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and the two forces on it so the two drum + + align:start position:0% +and the two forces on it so the two drum + + + align:start position:0% +and the two forces on it so the two drum +dumbbells sitting on a on a ring + + align:start position:0% +dumbbells sitting on a on a ring + + + align:start position:0% +dumbbells sitting on a on a ring +right + + align:start position:0% +right + + + align:start position:0% +right +think of it that way and you have two + + align:start position:0% +think of it that way and you have two + + + align:start position:0% +think of it that way and you have two +rockets attached to them they both apply + + align:start position:0% +rockets attached to them they both apply + + + align:start position:0% +rockets attached to them they both apply +forces heading that that way + + align:start position:0% +forces heading that that way + + + align:start position:0% +forces heading that that way +and the two forces are constant but they + + align:start position:0% +and the two forces are constant but they + + + align:start position:0% +and the two forces are constant but they +always head that way + + align:start position:0% +always head that way + + + align:start position:0% +always head that way +fp and fq + + align:start position:0% +fp and fq + + + align:start position:0% +fp and fq +and what we're trying to figure out is + + align:start position:0% +and what we're trying to figure out is + + + align:start position:0% +and what we're trying to figure out is +what this dumbbell does + + align:start position:0% +what this dumbbell does + + + align:start position:0% +what this dumbbell does +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so we'll come to the free body diagrams + + align:start position:0% +so we'll come to the free body diagrams + + + align:start position:0% +so we'll come to the free body diagrams +actually so the first thing you do is + + align:start position:0% +actually so the first thing you do is + + + align:start position:0% +actually so the first thing you do is +you draw a free body diagram + + align:start position:0% +you draw a free body diagram + + + align:start position:0% +you draw a free body diagram +and the free body diagrams are + + align:start position:0% +and the free body diagrams are + + + align:start position:0% +and the free body diagrams are +um + + align:start position:0% + + + + align:start position:0% + +what's the u here ok + + align:start position:0% + + + + align:start position:0% + +oh i see just the unit vector okay all + + align:start position:0% +oh i see just the unit vector okay all + + + align:start position:0% +oh i see just the unit vector okay all +right so essentially what uh what we're + + align:start position:0% +right so essentially what uh what we're + + + align:start position:0% +right so essentially what uh what we're +doing here is well we could have called + + align:start position:0% +doing here is well we could have called + + + align:start position:0% +doing here is well we could have called +it uh + + align:start position:0% +it uh + + + align:start position:0% +it uh +b1 right + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +okay so we can take each point mass + + align:start position:0% +okay so we can take each point mass + + + align:start position:0% +okay so we can take each point mass +this point mass has only two forces on + + align:start position:0% +this point mass has only two forces on + + + align:start position:0% +this point mass has only two forces on +it + + align:start position:0% +it + + + align:start position:0% +it +one force is this f and the other is a + + align:start position:0% +one force is this f and the other is a + + + align:start position:0% +one force is this f and the other is a +kind of a tension + + align:start position:0% +kind of a tension + + + align:start position:0% +kind of a tension +in the in the rod right we'll come to + + align:start position:0% +in the in the rod right we'll come to + + + align:start position:0% +in the in the rod right we'll come to +that in a second this point mass has the + + align:start position:0% +that in a second this point mass has the + + + align:start position:0% +that in a second this point mass has the +force fp and it has the tension in the + + align:start position:0% +force fp and it has the tension in the + + + align:start position:0% +force fp and it has the tension in the +rod this way right yes + + align:start position:0% +rod this way right yes + + + align:start position:0% +rod this way right yes +why is the tension along the rod anyone + + align:start position:0% + + + + align:start position:0% + +anybody + + align:start position:0% + + + + align:start position:0% + +yeah and why is that why does it have to + + align:start position:0% +yeah and why is that why does it have to + + + align:start position:0% +yeah and why is that why does it have to +be coaxial + + align:start position:0% +be coaxial + + + align:start position:0% +be coaxial +can a rod not apply a sideways force + + align:start position:0% +can a rod not apply a sideways force + + + align:start position:0% +can a rod not apply a sideways force +i mean i can do it right i can pick up a + + align:start position:0% +i mean i can do it right i can pick up a + + + align:start position:0% +i mean i can do it right i can pick up a +stick and wave it + + align:start position:0% +stick and wave it + + + align:start position:0% +stick and wave it +what was that + + align:start position:0% + + + + align:start position:0% + +well the reason actually is this + + align:start position:0% +well the reason actually is this + + + align:start position:0% +well the reason actually is this +if you just did a free body diagram on + + align:start position:0% +if you just did a free body diagram on + + + align:start position:0% +if you just did a free body diagram on +the rod and the tensions were not + + align:start position:0% +the rod and the tensions were not + + + align:start position:0% +the rod and the tensions were not +collinear + + align:start position:0% +collinear + + + align:start position:0% +collinear +and they were kind of skewed right that + + align:start position:0% +and they were kind of skewed right that + + + align:start position:0% +and they were kind of skewed right that +they didn't meet there would be a net + + align:start position:0% +they didn't meet there would be a net + + + align:start position:0% +they didn't meet there would be a net +torque on the rod + + align:start position:0% +torque on the rod + + + align:start position:0% +torque on the rod +but you know the mass of the rod is zero + + align:start position:0% +but you know the mass of the rod is zero + + + align:start position:0% +but you know the mass of the rod is zero +right + + align:start position:0% + + + + align:start position:0% + +so the change of momentum the rod is + + align:start position:0% +so the change of momentum the rod is + + + align:start position:0% +so the change of momentum the rod is +going to be zero + + align:start position:0% +going to be zero + + + align:start position:0% +going to be zero +change of angular momentum so the net + + align:start position:0% +change of angular momentum so the net + + + align:start position:0% +change of angular momentum so the net +torque must be zero + + align:start position:0% +torque must be zero + + + align:start position:0% +torque must be zero +get it + + align:start position:0% +get it + + + align:start position:0% +get it +the angular momentum of the torque is + + align:start position:0% +the angular momentum of the torque is + + + align:start position:0% +the angular momentum of the torque is +zero forever more + + align:start position:0% +zero forever more + + + align:start position:0% +zero forever more +so the rate of change of angular + + align:start position:0% +so the rate of change of angular + + + align:start position:0% +so the rate of change of angular +momentum is zero + + align:start position:0% +momentum is zero + + + align:start position:0% +momentum is zero +right + + align:start position:0% + + + + align:start position:0% + +and torque is equal to + + align:start position:0% +and torque is equal to + + + align:start position:0% +and torque is equal to +i alpha plus you know even if even if + + align:start position:0% +i alpha plus you know even if even if + + + align:start position:0% +i alpha plus you know even if even if +you take all this + + align:start position:0% +you take all this + + + align:start position:0% +you take all this +the right hand side is going to be zero + + align:start position:0% +the right hand side is going to be zero + + + align:start position:0% +the right hand side is going to be zero +so the torque is going to be zero which + + align:start position:0% +so the torque is going to be zero which + + + align:start position:0% +so the torque is going to be zero which +means that the tension forces have to be + + align:start position:0% +means that the tension forces have to be + + + align:start position:0% +means that the tension forces have to be +co-linear if you don't understand this + + align:start position:0% +co-linear if you don't understand this + + + align:start position:0% +co-linear if you don't understand this +i'll explain later it's not a big deal + + align:start position:0% +i'll explain later it's not a big deal + + + align:start position:0% +i'll explain later it's not a big deal +right assume that this is a sort of a + + align:start position:0% +right assume that this is a sort of a + + + align:start position:0% +right assume that this is a sort of a +struct which can only support + + align:start position:0% +struct which can only support + + + align:start position:0% +struct which can only support +compressive attention it can't support + + align:start position:0% +compressive attention it can't support + + + align:start position:0% +compressive attention it can't support +any bending that's the other way to + + align:start position:0% +any bending that's the other way to + + + align:start position:0% +any bending that's the other way to +think about it + + align:start position:0% +think about it + + + align:start position:0% +think about it +so these are the two forces + + align:start position:0% +so these are the two forces + + + align:start position:0% +so these are the two forces +so we've drawn a free body diagram then + + align:start position:0% +so we've drawn a free body diagram then + + + align:start position:0% +so we've drawn a free body diagram then +the next step + + align:start position:0% +the next step + + + align:start position:0% +the next step +is we're going to calculate the + + align:start position:0% +is we're going to calculate the + + + align:start position:0% +is we're going to calculate the +accelerations of points p and q all this + + align:start position:0% +accelerations of points p and q all this + + + align:start position:0% +accelerations of points p and q all this +i did in the last class right the + + align:start position:0% +i did in the last class right the + + + align:start position:0% +i did in the last class right the +acceleration of point p is ap + + align:start position:0% +acceleration of point p is ap + + + align:start position:0% +acceleration of point p is ap +is basically this vector + + align:start position:0% +is basically this vector + + + align:start position:0% +is basically this vector +plus this vector the rate of change of + + align:start position:0% +plus this vector the rate of change of + + + align:start position:0% +plus this vector the rate of change of +that + + align:start position:0% +that + + + align:start position:0% +that +right and you can use the ultra super + + align:start position:0% +right and you can use the ultra super + + + align:start position:0% +right and you can use the ultra super +cool magic formula if you want + + align:start position:0% +cool magic formula if you want + + + align:start position:0% +cool magic formula if you want +and what you get is the acceleration of + + align:start position:0% +and what you get is the acceleration of + + + align:start position:0% +and what you get is the acceleration of +point p is acceleration of point + + align:start position:0% +point p is acceleration of point + + + align:start position:0% +point p is acceleration of point +c + + align:start position:0% +c + + + align:start position:0% +c +right + + align:start position:0% +right + + + align:start position:0% +right +minus + + align:start position:0% +minus + + + align:start position:0% +minus +this what term is this + + align:start position:0% + + + + align:start position:0% + +centripetal term just from magic formula + + align:start position:0% +centripetal term just from magic formula + + + align:start position:0% +centripetal term just from magic formula +plus what is this + + align:start position:0% + + + + align:start position:0% + +euler formula right + + align:start position:0% + + + + align:start position:0% + +this is r i'm just writing in my + + align:start position:0% +this is r i'm just writing in my + + + align:start position:0% +this is r i'm just writing in my +handwriting right + + align:start position:0% +handwriting right + + + align:start position:0% +handwriting right +and then a q + + align:start position:0% +and then a q + + + align:start position:0% +and then a q +same thing right so we know the + + align:start position:0% +same thing right so we know the + + + align:start position:0% +same thing right so we know the +accelerations of the two endpoints right + + align:start position:0% +accelerations of the two endpoints right + + + align:start position:0% +accelerations of the two endpoints right +i'm going to stop here because i see + + align:start position:0% +i'm going to stop here because i see + + + align:start position:0% +i'm going to stop here because i see +some quizzical faces + + align:start position:0% + + + + align:start position:0% + +everyone good with this copacetic with + + align:start position:0% +everyone good with this copacetic with + + + align:start position:0% +everyone good with this copacetic with +this + + align:start position:0% +this + + + align:start position:0% +this +not a big deal all i'm saying is look + + align:start position:0% +not a big deal all i'm saying is look + + + align:start position:0% +not a big deal all i'm saying is look +the you know this end instead of finding + + align:start position:0% +the you know this end instead of finding + + + align:start position:0% +the you know this end instead of finding +the if i want to find the accelerations + + align:start position:0% +the if i want to find the accelerations + + + align:start position:0% +the if i want to find the accelerations +of the endpoints + + align:start position:0% +of the endpoints + + + align:start position:0% +of the endpoints +in terms of the + + align:start position:0% +in terms of the + + + align:start position:0% +in terms of the +coordinates i picked + + align:start position:0% +coordinates i picked + + + align:start position:0% +coordinates i picked +which are + + align:start position:0% +which are + + + align:start position:0% +which are +the center points kind of x and y + + align:start position:0% +the center points kind of x and y + + + align:start position:0% +the center points kind of x and y +location and the angle of the dumbbell + + align:start position:0% +location and the angle of the dumbbell + + + align:start position:0% +location and the angle of the dumbbell +this is how i would write it andrew + + align:start position:0% +this is how i would write it andrew + + + align:start position:0% +this is how i would write it andrew +everyone good + + align:start position:0% +everyone good + + + align:start position:0% +everyone good +go ahead see i knew + + align:start position:0% + + + + align:start position:0% + +okay let's talk about the tension here's + + align:start position:0% +okay let's talk about the tension here's + + + align:start position:0% +okay let's talk about the tension here's +why i don't have a place to write let me + + align:start position:0% +why i don't have a place to write let me + + + align:start position:0% +why i don't have a place to write let me +just write it here + + align:start position:0% + + + + align:start position:0% + +here's why + + align:start position:0% +here's why + + + align:start position:0% +here's why +this is the rod these are the spheres + + align:start position:0% +this is the rod these are the spheres + + + align:start position:0% +this is the rod these are the spheres +right the point masses i'm saying the + + align:start position:0% +right the point masses i'm saying the + + + align:start position:0% +right the point masses i'm saying the +tension has to be this way if the + + align:start position:0% +tension has to be this way if the + + + align:start position:0% +tension has to be this way if the +tension would ratchet this way + + align:start position:0% +tension would ratchet this way + + + align:start position:0% +tension would ratchet this way +they would still be equal and opposite + + align:start position:0% +they would still be equal and opposite + + + align:start position:0% +they would still be equal and opposite +so they would still + + align:start position:0% +so they would still + + + align:start position:0% +so they would still +satisfy the weak form of newton's law + + align:start position:0% +satisfy the weak form of newton's law + + + align:start position:0% +satisfy the weak form of newton's law +right + + align:start position:0% +right + + + align:start position:0% +right +even without invoking you know newton's + + align:start position:0% +even without invoking you know newton's + + + align:start position:0% +even without invoking you know newton's +strong form right + + align:start position:0% +strong form right + + + align:start position:0% +strong form right +the fact of the matter is if they're + + align:start position:0% +the fact of the matter is if they're + + + align:start position:0% +the fact of the matter is if they're +this way then if you just look at the + + align:start position:0% +this way then if you just look at the + + + align:start position:0% +this way then if you just look at the +rod + + align:start position:0% +rod + + + align:start position:0% +rod +does it have a net torque on it + + align:start position:0% + + + + align:start position:0% + +think about it if i take let's say it + + align:start position:0% +think about it if i take let's say it + + + align:start position:0% +think about it if i take let's say it +talks around this point the center of + + align:start position:0% +talks around this point the center of + + + align:start position:0% +talks around this point the center of +mass just the rod + + align:start position:0% + + + + align:start position:0% + +get it + + align:start position:0% +get it + + + align:start position:0% +get it +do you understand + + align:start position:0% +do you understand + + + align:start position:0% +do you understand +the torque if the rod is massless + + align:start position:0% +the torque if the rod is massless + + + align:start position:0% +the torque if the rod is massless +and it's got two forces creating a + + align:start position:0% +and it's got two forces creating a + + + align:start position:0% +and it's got two forces creating a +torque around it + + align:start position:0% +torque around it + + + align:start position:0% +torque around it +it'll have to accelerate at an infinite + + align:start position:0% +it'll have to accelerate at an infinite + + + align:start position:0% +it'll have to accelerate at an infinite +you know alpha or go to infinity right + + align:start position:0% +you know alpha or go to infinity right + + + align:start position:0% +you know alpha or go to infinity right +at some intuitive level do you + + align:start position:0% +at some intuitive level do you + + + align:start position:0% +at some intuitive level do you +understand what i'm saying + + align:start position:0% +understand what i'm saying + + + align:start position:0% +understand what i'm saying +right a massless rod + + align:start position:0% +right a massless rod + + + align:start position:0% +right a massless rod +therefore + + align:start position:0% + + + + align:start position:0% + +cannot have + + align:start position:0% +cannot have + + + align:start position:0% +cannot have +uh or the forces on it must be along + + align:start position:0% +uh or the forces on it must be along + + + align:start position:0% +uh or the forces on it must be along +the the line connecting the points they + + align:start position:0% +the the line connecting the points they + + + align:start position:0% +the the line connecting the points they +have to be collinear + + align:start position:0% +have to be collinear + + + align:start position:0% +have to be collinear +get it + + align:start position:0% +get it + + + align:start position:0% +get it +okay + + align:start position:0% +okay + + + align:start position:0% +okay +anyone not get this i can say it again + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and are you okay with that right + + align:start position:0% + + + + align:start position:0% + +anyway so now i got the accelerations of + + align:start position:0% +anyway so now i got the accelerations of + + + align:start position:0% +anyway so now i got the accelerations of +ap and aq and now i can write newton's + + align:start position:0% +ap and aq and now i can write newton's + + + align:start position:0% +ap and aq and now i can write newton's +laws right + + align:start position:0% +laws right + + + align:start position:0% +laws right +so i can write newton's law for this guy + + align:start position:0% +so i can write newton's law for this guy + + + align:start position:0% +so i can write newton's law for this guy +f q minus t b1 + + align:start position:0% +f q minus t b1 + + + align:start position:0% +f q minus t b1 +right fq minus t + + align:start position:0% +right fq minus t + + + align:start position:0% +right fq minus t +b1 + + align:start position:0% + + + + align:start position:0% + +f q minus t b 1 is equal to mass times + + align:start position:0% +f q minus t b 1 is equal to mass times + + + align:start position:0% +f q minus t b 1 is equal to mass times +acceleration of + + align:start position:0% +acceleration of + + + align:start position:0% +acceleration of +point of particle q + + align:start position:0% +point of particle q + + + align:start position:0% +point of particle q +f p plus t b b 1 is mass times + + align:start position:0% +f p plus t b b 1 is mass times + + + align:start position:0% +f p plus t b b 1 is mass times +acceleration of point p + + align:start position:0% +acceleration of point p + + + align:start position:0% +acceleration of point p +good + + align:start position:0% +good + + + align:start position:0% +good +i've done i actually have this is + + align:start position:0% +i've done i actually have this is + + + align:start position:0% +i've done i actually have this is +actually very simple i mean i you know + + align:start position:0% +actually very simple i mean i you know + + + align:start position:0% +actually very simple i mean i you know +sometimes i'm saying things so simply + + align:start position:0% +sometimes i'm saying things so simply + + + align:start position:0% +sometimes i'm saying things so simply +that you might get confused + + align:start position:0% +that you might get confused + + + align:start position:0% +that you might get confused +any questions from anyone you can stop + + align:start position:0% +any questions from anyone you can stop + + + align:start position:0% +any questions from anyone you can stop +me here if you want + + align:start position:0% + + + + align:start position:0% + +first step + + align:start position:0% +first step + + + align:start position:0% +first step +label and draw everything second step + + align:start position:0% +label and draw everything second step + + + align:start position:0% +label and draw everything second step +draw the free body diagram third step + + align:start position:0% +draw the free body diagram third step + + + align:start position:0% +draw the free body diagram third step +figure out the accelerations fourth step + + align:start position:0% +figure out the accelerations fourth step + + + align:start position:0% +figure out the accelerations fourth step +right f is equal to m a + + align:start position:0% +right f is equal to m a + + + align:start position:0% +right f is equal to m a +that's what i just did well that's what + + align:start position:0% +that's what i just did well that's what + + + align:start position:0% +that's what i just did well that's what +rj did + + align:start position:0% +rj did + + + align:start position:0% +rj did +right + + align:start position:0% + + + + align:start position:0% + +now + + align:start position:0% +now + + + align:start position:0% +now +actually what happens next is + + align:start position:0% +actually what happens next is + + + align:start position:0% +actually what happens next is +look you have + + align:start position:0% +look you have + + + align:start position:0% +look you have +two equations + + align:start position:0% +two equations + + + align:start position:0% +two equations +they're both vector equations + + align:start position:0% +they're both vector equations + + + align:start position:0% +they're both vector equations +right + + align:start position:0% +right + + + align:start position:0% +right +and at some level + + align:start position:0% +and at some level + + + align:start position:0% +and at some level +you have + + align:start position:0% + + + + align:start position:0% + +three unknowns + + align:start position:0% +three unknowns + + + align:start position:0% +three unknowns +so there's actually four equations right + + align:start position:0% +so there's actually four equations right + + + align:start position:0% +so there's actually four equations right +but you have + + align:start position:0% +but you have + + + align:start position:0% +but you have +how many unknowns what are the unknowns + + align:start position:0% +how many unknowns what are the unknowns + + + align:start position:0% +how many unknowns what are the unknowns +the x location of the rod the y location + + align:start position:0% +the x location of the rod the y location + + + align:start position:0% +the x location of the rod the y location +of center of the rod the angle is there + + align:start position:0% +of center of the rod the angle is there + + + align:start position:0% +of center of the rod the angle is there +any other unknown + + align:start position:0% + + + + align:start position:0% + +anybody + + align:start position:0% + + + + align:start position:0% + +anyone + + align:start position:0% + + + + align:start position:0% + +well okay so let's list them again what + + align:start position:0% +well okay so let's list them again what + + + align:start position:0% +well okay so let's list them again what +are the unknowns + + align:start position:0% +are the unknowns + + + align:start position:0% +are the unknowns +you want to know where the orders x y + + align:start position:0% +you want to know where the orders x y + + + align:start position:0% +you want to know where the orders x y +and angle that's three + + align:start position:0% +and angle that's three + + + align:start position:0% +and angle that's three +i have four equations so there must be + + align:start position:0% +i have four equations so there must be + + + align:start position:0% +i have four equations so there must be +one more unknown right + + align:start position:0% + + + + align:start position:0% + +tension + + align:start position:0% +tension + + + align:start position:0% +tension +okay + + align:start position:0% +okay + + + align:start position:0% +okay +if the two rods weren't connected the + + align:start position:0% +if the two rods weren't connected the + + + align:start position:0% +if the two rods weren't connected the +fourth unknown would be like + + align:start position:0% +fourth unknown would be like + + + align:start position:0% +fourth unknown would be like +you know x y x y of the two you know two + + align:start position:0% +you know x y x y of the two you know two + + + align:start position:0% +you know x y x y of the two you know two +bodies + + align:start position:0% +bodies + + + align:start position:0% +bodies +and there wouldn't be a tension so if + + align:start position:0% +and there wouldn't be a tension so if + + + align:start position:0% +and there wouldn't be a tension so if +there's a kinematic constraint + + align:start position:0% +there's a kinematic constraint + + + align:start position:0% +there's a kinematic constraint +one of the + + align:start position:0% +one of the + + + align:start position:0% +one of the +degrees of freedom would go away but an + + align:start position:0% +degrees of freedom would go away but an + + + align:start position:0% +degrees of freedom would go away but an +unknown force replaces it you understand + + align:start position:0% +unknown force replaces it you understand + + + align:start position:0% +unknown force replaces it you understand +it's very important that you get this + + align:start position:0% +it's very important that you get this + + + align:start position:0% +it's very important that you get this +gestalt + + align:start position:0% +gestalt + + + align:start position:0% +gestalt +all right + + align:start position:0% +all right + + + align:start position:0% +all right +okay so + + align:start position:0% +okay so + + + align:start position:0% +okay so +four equations four unknowns + + align:start position:0% +four equations four unknowns + + + align:start position:0% +four equations four unknowns +you should be able to solve it + + align:start position:0% +you should be able to solve it + + + align:start position:0% +you should be able to solve it +okay + + align:start position:0% +okay + + + align:start position:0% +okay +but now let's solve it + + align:start position:0% +but now let's solve it + + + align:start position:0% +but now let's solve it +and i want to show you something + + align:start position:0% +and i want to show you something + + + align:start position:0% +and i want to show you something +interesting + + align:start position:0% + + + + align:start position:0% + +now what do you have what do you do when + + align:start position:0% +now what do you have what do you do when + + + align:start position:0% +now what do you have what do you do when +you have simultaneous equations you + + align:start position:0% +you have simultaneous equations you + + + align:start position:0% +you have simultaneous equations you +subtract them you add them you eliminate + + align:start position:0% +subtract them you add them you eliminate + + + align:start position:0% +subtract them you add them you eliminate +terms right + + align:start position:0% +terms right + + + align:start position:0% +terms right +i'm just going to do them all in vector + + align:start position:0% +i'm just going to do them all in vector + + + align:start position:0% +i'm just going to do them all in vector +form + + align:start position:0% +form + + + align:start position:0% +form +so if i add these two equations + + align:start position:0% +so if i add these two equations + + + align:start position:0% +so if i add these two equations +1 and 2 + + align:start position:0% +1 and 2 + + + align:start position:0% +1 and 2 +this term will cancel out right + + align:start position:0% +this term will cancel out right + + + align:start position:0% +this term will cancel out right +so i'll get f p plus f q + + align:start position:0% +so i'll get f p plus f q + + + align:start position:0% +so i'll get f p plus f q +is equal to the sum of these two guys + + align:start position:0% +is equal to the sum of these two guys + + + align:start position:0% +is equal to the sum of these two guys +correct + + align:start position:0% +correct + + + align:start position:0% +correct +so that's the first equation here + + align:start position:0% +so that's the first equation here + + + align:start position:0% +so that's the first equation here +f p plus f q is equal to 2 m a + + align:start position:0% +f p plus f q is equal to 2 m a + + + align:start position:0% +f p plus f q is equal to 2 m a +acceleration of center of mass + + align:start position:0% +acceleration of center of mass + + + align:start position:0% +acceleration of center of mass +got it + + align:start position:0% + + + + align:start position:0% + +yeah so that's the only little bit of + + align:start position:0% +yeah so that's the only little bit of + + + align:start position:0% +yeah so that's the only little bit of +you know shell game i played here + + align:start position:0% +you know shell game i played here + + + align:start position:0% +you know shell game i played here +m a + + align:start position:0% +m a + + + align:start position:0% +m a +so the definition of the center of mass + + align:start position:0% +so the definition of the center of mass + + + align:start position:0% +so the definition of the center of mass +is the so that's how that's the + + align:start position:0% +is the so that's how that's the + + + align:start position:0% +is the so that's how that's the +definition of the center of mass right + + align:start position:0% +definition of the center of mass right + + + align:start position:0% +definition of the center of mass right +if you take the acceleration of one end + + align:start position:0% +if you take the acceleration of one end + + + align:start position:0% +if you take the acceleration of one end +times the mass of that end + + align:start position:0% +times the mass of that end + + + align:start position:0% +times the mass of that end +plus the acceleration on the other end + + align:start position:0% +plus the acceleration on the other end + + + align:start position:0% +plus the acceleration on the other end +plus the mass of the other end + + align:start position:0% +plus the mass of the other end + + + align:start position:0% +plus the mass of the other end +right what you get + + align:start position:0% +right what you get + + + align:start position:0% +right what you get +is like two times that mass at the + + align:start position:0% +is like two times that mass at the + + + align:start position:0% +is like two times that mass at the +center of mass at the center of mass + + align:start position:0% +center of mass at the center of mass + + + align:start position:0% +center of mass at the center of mass +accelerating with the acceleration + + align:start position:0% +accelerating with the acceleration + + + align:start position:0% +accelerating with the acceleration +center of mass all right + + align:start position:0% +center of mass all right + + + align:start position:0% +center of mass all right +this will become more clear in a minute + + align:start position:0% +this will become more clear in a minute + + + align:start position:0% +this will become more clear in a minute +when i do the actual derivation you'll + + align:start position:0% +when i do the actual derivation you'll + + + align:start position:0% +when i do the actual derivation you'll +see it but essentially when you add maap + + align:start position:0% +see it but essentially when you add maap + + + align:start position:0% +see it but essentially when you add maap +plus maaq + + align:start position:0% +plus maaq + + + align:start position:0% +plus maaq +it's the same as + + align:start position:0% + + + + align:start position:0% + +2m + + align:start position:0% +2m + + + align:start position:0% +2m +times acceleration the central mass is + + align:start position:0% +times acceleration the central mass is + + + align:start position:0% +times acceleration the central mass is +the weighted average that's what the + + align:start position:0% +the weighted average that's what the + + + align:start position:0% +the weighted average that's what the +central mass will do don't worry i'll + + align:start position:0% +central mass will do don't worry i'll + + + align:start position:0% +central mass will do don't worry i'll +nail this in a minute okay so it's a + + align:start position:0% +nail this in a minute okay so it's a + + + align:start position:0% +nail this in a minute okay so it's a +good good catch that was a little bit of + + align:start position:0% +good good catch that was a little bit of + + + align:start position:0% +good good catch that was a little bit of +shell game i played + + align:start position:0% +shell game i played + + + align:start position:0% +shell game i played +all right + + align:start position:0% +all right + + + align:start position:0% +all right +actually rj played it not me i would + + align:start position:0% +actually rj played it not me i would + + + align:start position:0% +actually rj played it not me i would +have you know if i derived it i was + + align:start position:0% +have you know if i derived it i was + + + align:start position:0% +have you know if i derived it i was +shown you you know very carefully but he + + align:start position:0% +shown you you know very carefully but he + + + align:start position:0% +shown you you know very carefully but he +what did you derive it + + align:start position:0% + + + + align:start position:0% + +said again i'm sorry + + align:start position:0% +said again i'm sorry + + + align:start position:0% +said again i'm sorry +yeah actually actually + + align:start position:0% +yeah actually actually + + + align:start position:0% +yeah actually actually +thank you + + align:start position:0% +thank you + + + align:start position:0% +thank you +if you write ap + + align:start position:0% +if you write ap + + + align:start position:0% +if you write ap +and aq in terms of these two terms + + align:start position:0% +and aq in terms of these two terms + + + align:start position:0% +and aq in terms of these two terms +right it'll all cancel out + + align:start position:0% +right it'll all cancel out + + + align:start position:0% +right it'll all cancel out +good catch + + align:start position:0% +good catch + + + align:start position:0% +good catch +all right but it's also the definition + + align:start position:0% +all right but it's also the definition + + + align:start position:0% +all right but it's also the definition +of the center of mass just so you know + + align:start position:0% +of the center of mass just so you know + + + align:start position:0% +of the center of mass just so you know +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so if you just expand this right just + + align:start position:0% +so if you just expand this right just + + + align:start position:0% +so if you just expand this right just +write ap + + align:start position:0% +write ap + + + align:start position:0% +write ap +then see this term will cancel out + + align:start position:0% +then see this term will cancel out + + + align:start position:0% +then see this term will cancel out +this term will remain and this term will + + align:start position:0% +this term will remain and this term will + + + align:start position:0% +this term will remain and this term will +remain right and even this will cancel + + align:start position:0% +remain right and even this will cancel + + + align:start position:0% +remain right and even this will cancel +out so all you'll get is two times this + + align:start position:0% +out so all you'll get is two times this + + + align:start position:0% +out so all you'll get is two times this +okay so you'll get that anyway + + align:start position:0% +okay so you'll get that anyway + + + align:start position:0% +okay so you'll get that anyway +everyone's good with that adding up the + + align:start position:0% +everyone's good with that adding up the + + + align:start position:0% +everyone's good with that adding up the +equations + + align:start position:0% +equations + + + align:start position:0% +equations +right + + align:start position:0% +right + + + align:start position:0% +right +now so that's the first one take a1 and + + align:start position:0% +now so that's the first one take a1 and + + + align:start position:0% +now so that's the first one take a1 and +a2 + + align:start position:0% +a2 + + + align:start position:0% +a2 +and add up + + align:start position:0% +and add up + + + align:start position:0% +and add up +the second reduction i'm going to do + + align:start position:0% +the second reduction i'm going to do + + + align:start position:0% +the second reduction i'm going to do +is i'm going to take equation multiple + + align:start position:0% +is i'm going to take equation multiple + + + align:start position:0% +is i'm going to take equation multiple +one + + align:start position:0% +one + + + align:start position:0% +one +pre-cross product it with rcp + + align:start position:0% +pre-cross product it with rcp + + + align:start position:0% +pre-cross product it with rcp +okay + + align:start position:0% +okay + + + align:start position:0% +okay +which is basically the moment let me + + align:start position:0% +which is basically the moment let me + + + align:start position:0% +which is basically the moment let me +explain that + + align:start position:0% +explain that + + + align:start position:0% +explain that +so i'm going to take equation one + + align:start position:0% +so i'm going to take equation one + + + align:start position:0% +so i'm going to take equation one +this guy + + align:start position:0% +this guy + + + align:start position:0% +this guy +and go rcp cross this plus rcp cross + + align:start position:0% +and go rcp cross this plus rcp cross + + + align:start position:0% +and go rcp cross this plus rcp cross +this plus rcp across this still a valid + + align:start position:0% +this plus rcp across this still a valid + + + align:start position:0% +this plus rcp across this still a valid +equation right + + align:start position:0% +equation right + + + align:start position:0% +equation right +and i'm going to take equation two and + + align:start position:0% +and i'm going to take equation two and + + + align:start position:0% +and i'm going to take equation two and +go r c q cross this + + align:start position:0% +go r c q cross this + + + align:start position:0% +go r c q cross this +minus r c q cross this is equal to r c q + + align:start position:0% +minus r c q cross this is equal to r c q + + + align:start position:0% +minus r c q cross this is equal to r c q +cross this and add them up + + align:start position:0% +cross this and add them up + + + align:start position:0% +cross this and add them up +get it so it's kind of like taking + + align:start position:0% +get it so it's kind of like taking + + + align:start position:0% +get it so it's kind of like taking +simultaneous equations you know + + align:start position:0% +simultaneous equations you know + + + align:start position:0% +simultaneous equations you know +multiplying all the terms by something + + align:start position:0% +multiplying all the terms by something + + + align:start position:0% +multiplying all the terms by something +and then you know adding it that kind of + + align:start position:0% +and then you know adding it that kind of + + + align:start position:0% +and then you know adding it that kind of +thing + + align:start position:0% +thing + + + align:start position:0% +thing +right + + align:start position:0% + + + + align:start position:0% + +we'll give you a handwritten version of + + align:start position:0% +we'll give you a handwritten version of + + + align:start position:0% +we'll give you a handwritten version of +this don't worry + + align:start position:0% +this don't worry + + + align:start position:0% +this don't worry +okay you'll see it i wanted to make a + + align:start position:0% +okay you'll see it i wanted to make a + + + align:start position:0% +okay you'll see it i wanted to make a +very simple point + + align:start position:0% +very simple point + + + align:start position:0% +very simple point +which was that if you do that + + align:start position:0% +which was that if you do that + + + align:start position:0% +which was that if you do that +and you do all the math + + align:start position:0% +and you do all the math + + + align:start position:0% +and you do all the math +a lot of terms will cancel out + + align:start position:0% +a lot of terms will cancel out + + + align:start position:0% +a lot of terms will cancel out +and guess what you will end up with + + align:start position:0% +and guess what you will end up with + + + align:start position:0% +and guess what you will end up with +you will end up with rcq cross + + align:start position:0% +you will end up with rcq cross + + + align:start position:0% +you will end up with rcq cross +so + + align:start position:0% +so + + + align:start position:0% +so +i just do that now you know cancel all + + align:start position:0% +i just do that now you know cancel all + + + align:start position:0% +i just do that now you know cancel all +our terms will cancel out right i'll end + + align:start position:0% +our terms will cancel out right i'll end + + + align:start position:0% +our terms will cancel out right i'll end +up with rcq cross so you don't have to + + align:start position:0% +up with rcq cross so you don't have to + + + align:start position:0% +up with rcq cross so you don't have to +write this down guys we'll give this to + + align:start position:0% +write this down guys we'll give this to + + + align:start position:0% +write this down guys we'll give this to +you + + align:start position:0% +you + + + align:start position:0% +you +all right i'm trying to make a deeper + + align:start position:0% +all right i'm trying to make a deeper + + + align:start position:0% +all right i'm trying to make a deeper +point here not the map point + + align:start position:0% +point here not the map point + + + align:start position:0% +point here not the map point +all right the math trust me if you check + + align:start position:0% +all right the math trust me if you check + + + align:start position:0% +all right the math trust me if you check +through it it all works out + + align:start position:0% +through it it all works out + + + align:start position:0% +through it it all works out +r c q cross f q minus f p + + align:start position:0% +r c q cross f q minus f p + + + align:start position:0% +r c q cross f q minus f p +you will get is equal to m r squared + + align:start position:0% + + + + align:start position:0% + +a alpha b + + align:start position:0% +a alpha b + + + align:start position:0% +a alpha b +okay and i want you to stare at this for + + align:start position:0% +okay and i want you to stare at this for + + + align:start position:0% +okay and i want you to stare at this for +a second because it's really cool + + align:start position:0% + + + + align:start position:0% + +here's what's really cool about it + + align:start position:0% +here's what's really cool about it + + + align:start position:0% +here's what's really cool about it +and by the way i i eliminate t right if + + align:start position:0% +and by the way i i eliminate t right if + + + align:start position:0% +and by the way i i eliminate t right if +you you can come up with another + + align:start position:0% +you you can come up with another + + + align:start position:0% +you you can come up with another +equation it tells you what t is but + + align:start position:0% +equation it tells you what t is but + + + align:start position:0% +equation it tells you what t is but +essentially i've solved the problem + + align:start position:0% +essentially i've solved the problem + + + align:start position:0% +essentially i've solved the problem +this is saying the sum of forces + + align:start position:0% +this is saying the sum of forces + + + align:start position:0% +this is saying the sum of forces +on the particles + + align:start position:0% +on the particles + + + align:start position:0% +on the particles +if you take if you take the two + + align:start position:0% +if you take if you take the two + + + align:start position:0% +if you take if you take the two +particles and treat them like one + + align:start position:0% +particles and treat them like one + + + align:start position:0% +particles and treat them like one +particle with twice its mass right at + + align:start position:0% +particle with twice its mass right at + + + align:start position:0% +particle with twice its mass right at +the center of mass + + align:start position:0% +the center of mass + + + align:start position:0% +the center of mass +right + + align:start position:0% +right + + + align:start position:0% +right +the sum of forces is equal to + + align:start position:0% +the sum of forces is equal to + + + align:start position:0% +the sum of forces is equal to +m a + + align:start position:0% +m a + + + align:start position:0% +m a +mass of this kind of combined + + align:start position:0% +mass of this kind of combined + + + align:start position:0% +mass of this kind of combined +you know lumped particle + + align:start position:0% +you know lumped particle + + + align:start position:0% +you know lumped particle +times the acceleration center of mass + + align:start position:0% +times the acceleration center of mass + + + align:start position:0% +times the acceleration center of mass +that's inside number one + + align:start position:0% +that's inside number one + + + align:start position:0% +that's inside number one +right + + align:start position:0% + + + + align:start position:0% + +can anyone interpret this for me + + align:start position:0% + + + + align:start position:0% + +torque is equal to i alpha do you + + align:start position:0% +torque is equal to i alpha do you + + + align:start position:0% +torque is equal to i alpha do you +understand this + + align:start position:0% + + + + align:start position:0% + +this is simply the torque about the + + align:start position:0% +this is simply the torque about the + + + align:start position:0% +this is simply the torque about the +center of mass + + align:start position:0% +center of mass + + + align:start position:0% +center of mass +and in our math + + align:start position:0% +and in our math + + + align:start position:0% +and in our math +out popped + + align:start position:0% +out popped + + + align:start position:0% +out popped +what is actually + + align:start position:0% +what is actually + + + align:start position:0% +what is actually +the moment of inertia + + align:start position:0% +the moment of inertia + + + align:start position:0% +the moment of inertia +although i haven't defined it you + + align:start position:0% +although i haven't defined it you + + + align:start position:0% +although i haven't defined it you +officially yet + + align:start position:0% +officially yet + + + align:start position:0% +officially yet +the moment of inertia + + align:start position:0% +the moment of inertia + + + align:start position:0% +the moment of inertia +of this dumbbell + + align:start position:0% +of this dumbbell + + + align:start position:0% +of this dumbbell +multiplied by alpha + + align:start position:0% +multiplied by alpha + + + align:start position:0% +multiplied by alpha +torque is equal to i alpha + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +and there's a reason we did all this + + align:start position:0% +and there's a reason we did all this + + + align:start position:0% +and there's a reason we did all this +and the reason was to give you a hint + + align:start position:0% +and the reason was to give you a hint + + + align:start position:0% +and the reason was to give you a hint +of what was going to come ahead + + align:start position:0% +of what was going to come ahead + + + align:start position:0% +of what was going to come ahead +so my question to you first is + + align:start position:0% +so my question to you first is + + + align:start position:0% +so my question to you first is +do you understand this + + align:start position:0% +do you understand this + + + align:start position:0% +do you understand this +do you understand what i'm trying to say + + align:start position:0% +do you understand what i'm trying to say + + + align:start position:0% +do you understand what i'm trying to say +can anyone yep levi + + align:start position:0% + + + + align:start position:0% + +i don't really always understand what + + align:start position:0% +i don't really always understand what + + + align:start position:0% +i don't really always understand what +you are talking about + + align:start position:0% +you are talking about + + + align:start position:0% +you are talking about +uh okay + + align:start position:0% +uh okay + + + align:start position:0% +uh okay +we uh i didn't emphasize it but in the + + align:start position:0% +we uh i didn't emphasize it but in the + + + align:start position:0% +we uh i didn't emphasize it but in the +drawing last last week + + align:start position:0% +drawing last last week + + + align:start position:0% +drawing last last week +we defined + + align:start position:0% +we defined + + + align:start position:0% +we defined +the length of the rod + + align:start position:0% +the length of the rod + + + align:start position:0% +the length of the rod +as 2r + + align:start position:0% +as 2r + + + align:start position:0% +as 2r +there are a lot of r's floating around + + align:start position:0% +there are a lot of r's floating around + + + align:start position:0% +there are a lot of r's floating around +all right r is a position vector but an + + align:start position:0% +all right r is a position vector but an + + + align:start position:0% +all right r is a position vector but an +unsubscripted unvectored r is simply the + + align:start position:0% +unsubscripted unvectored r is simply the + + + align:start position:0% +unsubscripted unvectored r is simply the +length of the uh + + align:start position:0% +length of the uh + + + align:start position:0% +length of the uh +dumbbell + + align:start position:0% + + + + align:start position:0% + +say it again + + align:start position:0% +say it again + + + align:start position:0% +say it again +so they're all + + align:start position:0% +so they're all + + + align:start position:0% +so they're all +unsubscriptive + + align:start position:0% +unsubscriptive + + + align:start position:0% +unsubscriptive +but they're all vectors + + align:start position:0% +but they're all vectors + + + align:start position:0% +but they're all vectors +no no + + align:start position:0% +no no + + + align:start position:0% +no no +which maybe we shouldn't have used r + + align:start position:0% +which maybe we shouldn't have used r + + + align:start position:0% +which maybe we shouldn't have used r +maybe we should have called this l + + align:start position:0% +maybe we should have called this l + + + align:start position:0% +maybe we should have called this l +get it just this length of the dumbbell + + align:start position:0% +get it just this length of the dumbbell + + + align:start position:0% +get it just this length of the dumbbell +then this would have been then this + + align:start position:0% +then this would have been then this + + + align:start position:0% +then this would have been then this +would have been 2 m l squared a alpha b + + align:start position:0% +would have been 2 m l squared a alpha b + + + align:start position:0% +would have been 2 m l squared a alpha b +got it it's just another it's just it's + + align:start position:0% +got it it's just another it's just it's + + + align:start position:0% +got it it's just another it's just it's +just a + + align:start position:0% +just a + + + align:start position:0% +just a +it's the length of the rod + + align:start position:0% +it's the length of the rod + + + align:start position:0% +it's the length of the rod +it's 2r right that's you think of it as + + align:start position:0% +it's 2r right that's you think of it as + + + align:start position:0% +it's 2r right that's you think of it as +2l then this would be m 2 m l squared + + align:start position:0% +2l then this would be m 2 m l squared + + + align:start position:0% +2l then this would be m 2 m l squared +alpha b + + align:start position:0% +alpha b + + + align:start position:0% +alpha b +you understand yeah okay someone else + + align:start position:0% +you understand yeah okay someone else + + + align:start position:0% +you understand yeah okay someone else +had a question here do you have a + + align:start position:0% +had a question here do you have a + + + align:start position:0% +had a question here do you have a +question anybody else + + align:start position:0% +question anybody else + + + align:start position:0% +question anybody else +look here's what i was trying to say + + align:start position:0% +look here's what i was trying to say + + + align:start position:0% +look here's what i was trying to say +you want to send f is equal to m a for + + align:start position:0% +you want to send f is equal to m a for + + + align:start position:0% +you want to send f is equal to m a for +particles right totally get it + + align:start position:0% +particles right totally get it + + + align:start position:0% +particles right totally get it +here's the deal guys + + align:start position:0% +here's the deal guys + + + align:start position:0% +here's the deal guys +if you have multiple particle systems + + align:start position:0% +if you have multiple particle systems + + + align:start position:0% +if you have multiple particle systems +for example a two particle system + + align:start position:0% +for example a two particle system + + + align:start position:0% +for example a two particle system +where the two particles are rigidly + + align:start position:0% +where the two particles are rigidly + + + align:start position:0% +where the two particles are rigidly +attached + + align:start position:0% +attached + + + align:start position:0% +attached +you can apply a physical ma to each + + align:start position:0% +you can apply a physical ma to each + + + align:start position:0% +you can apply a physical ma to each +particle + + align:start position:0% +particle + + + align:start position:0% +particle +and assume an unknown force and just + + align:start position:0% +and assume an unknown force and just + + + align:start position:0% +and assume an unknown force and just +solve it that's completely completely + + align:start position:0% +solve it that's completely completely + + + align:start position:0% +solve it that's completely completely +correct we just did it + + align:start position:0% +correct we just did it + + + align:start position:0% +correct we just did it +completely correct + + align:start position:0% +completely correct + + + align:start position:0% +completely correct +when you do it + + align:start position:0% +when you do it + + + align:start position:0% +when you do it +what you'll find is when you solve all + + align:start position:0% +what you'll find is when you solve all + + + align:start position:0% +what you'll find is when you solve all +the equations + + align:start position:0% +the equations + + + align:start position:0% +the equations +they will reduce to a very interesting + + align:start position:0% +they will reduce to a very interesting + + + align:start position:0% +they will reduce to a very interesting +form which is + + align:start position:0% +form which is + + + align:start position:0% +form which is +f is equal to m a for the center of mass + + align:start position:0% +f is equal to m a for the center of mass + + + align:start position:0% +f is equal to m a for the center of mass +and + + align:start position:0% +and + + + align:start position:0% +and +this funky new term that keeps cropping + + align:start position:0% +this funky new term that keeps cropping + + + align:start position:0% +this funky new term that keeps cropping +up which we've kind of already defined + + align:start position:0% +up which we've kind of already defined + + + align:start position:0% +up which we've kind of already defined +which is + + align:start position:0% +which is + + + align:start position:0% +which is +this thing which is actually the torque + + align:start position:0% +this thing which is actually the torque + + + align:start position:0% +this thing which is actually the torque +times i + + align:start position:0% +times i + + + align:start position:0% +times i +this kind of mr squared kind of term 2mr + + align:start position:0% +this kind of mr squared kind of term 2mr + + + align:start position:0% +this kind of mr squared kind of term 2mr +squared + + align:start position:0% +squared + + + align:start position:0% +squared +alpha + + align:start position:0% +alpha + + + align:start position:0% +alpha +and this will keep cropping up if you + + align:start position:0% +and this will keep cropping up if you + + + align:start position:0% +and this will keep cropping up if you +have three particles you will get the + + align:start position:0% +have three particles you will get the + + + align:start position:0% +have three particles you will get the +same thing you get four particles you + + align:start position:0% +same thing you get four particles you + + + align:start position:0% +same thing you get four particles you +get the same thing 300 million particles + + align:start position:0% +get the same thing 300 million particles + + + align:start position:0% +get the same thing 300 million particles +a lot of equations you would still end + + align:start position:0% +a lot of equations you would still end + + + align:start position:0% +a lot of equations you would still end +up with the same thing + + align:start position:0% +up with the same thing + + + align:start position:0% +up with the same thing +got it + + align:start position:0% +got it + + + align:start position:0% +got it +so why not we just derive the same thing + + align:start position:0% +so why not we just derive the same thing + + + align:start position:0% +so why not we just derive the same thing +once and for all + + align:start position:0% +once and for all + + + align:start position:0% +once and for all +and we can show that tau is equal to i + + align:start position:0% +and we can show that tau is equal to i + + + align:start position:0% +and we can show that tau is equal to i +alpha around the center of mass and then + + align:start position:0% +alpha around the center of mass and then + + + align:start position:0% +alpha around the center of mass and then +every time we see a rigid body we can + + align:start position:0% +every time we see a rigid body we can + + + align:start position:0% +every time we see a rigid body we can +just use that directly + + align:start position:0% +just use that directly + + + align:start position:0% +just use that directly +get it + + align:start position:0% +get it + + + align:start position:0% +get it +but there's nothing new in here all i'm + + align:start position:0% +but there's nothing new in here all i'm + + + align:start position:0% +but there's nothing new in here all i'm +saying what nothing shocking what i'm + + align:start position:0% +saying what nothing shocking what i'm + + + align:start position:0% +saying what nothing shocking what i'm +doing i'm just going to derive this for + + align:start position:0% +doing i'm just going to derive this for + + + align:start position:0% +doing i'm just going to derive this for +an infinite or any number of particle + + align:start position:0% +an infinite or any number of particle + + + align:start position:0% +an infinite or any number of particle +system i'm going to show that torque is + + align:start position:0% +system i'm going to show that torque is + + + align:start position:0% +system i'm going to show that torque is +a chloride alpha but you can see from a + + align:start position:0% +a chloride alpha but you can see from a + + + align:start position:0% +a chloride alpha but you can see from a +two particle system you can show toxic + + align:start position:0% +two particle system you can show toxic + + + align:start position:0% +two particle system you can show toxic +i-alpha + + align:start position:0% +i-alpha + + + align:start position:0% +i-alpha +get it no yes maybe + + align:start position:0% + + + + align:start position:0% + +it's good + + align:start position:0% +it's good + + + align:start position:0% +it's good +okay + + align:start position:0% +okay + + + align:start position:0% +okay +that was the objective of this exercise + + align:start position:0% +that was the objective of this exercise + + + align:start position:0% +that was the objective of this exercise +was to just give you that + + align:start position:0% +was to just give you that + + + align:start position:0% +was to just give you that +taste + + align:start position:0% +taste + + + align:start position:0% +taste +of what uh what we're going to do next + + align:start position:0% +of what uh what we're going to do next + + + align:start position:0% +of what uh what we're going to do next +so what we're going to do next + + align:start position:0% +so what we're going to do next + + + align:start position:0% +so what we're going to do next +is we're going to take + + align:start position:0% +is we're going to take + + + align:start position:0% +is we're going to take +millions of particles + + align:start position:0% +millions of particles + + + align:start position:0% +millions of particles +right + + align:start position:0% +right + + + align:start position:0% +right +and + + align:start position:0% +and + + + align:start position:0% +and +do the same thing except we'll do it in + + align:start position:0% +do the same thing except we'll do it in + + + align:start position:0% +do the same thing except we'll do it in +a kind of a generalized format + + align:start position:0% +a kind of a generalized format + + + align:start position:0% +a kind of a generalized format +and that's called a derivation and the + + align:start position:0% +and that's called a derivation and the + + + align:start position:0% +and that's called a derivation and the +output is going to be that same result + + align:start position:0% +output is going to be that same result + + + align:start position:0% +output is going to be that same result +but in a generalized way it's a general + + align:start position:0% +but in a generalized way it's a general + + + align:start position:0% +but in a generalized way it's a general +formula okay + + align:start position:0% + + + + align:start position:0% + +oops + + align:start position:0% + + + + align:start position:0% + +huh + + align:start position:0% + + + + align:start position:0% + +oh raise it i'm sorry i thought you said + + align:start position:0% +oh raise it i'm sorry i thought you said + + + align:start position:0% +oh raise it i'm sorry i thought you said +erase it i was like what do you want to + + align:start position:0% +erase it i was like what do you want to + + + align:start position:0% +erase it i was like what do you want to +erase it it's only below what do you + + align:start position:0% +erase it it's only below what do you + + + align:start position:0% +erase it it's only below what do you +want me to erase it guys don't seriously + + align:start position:0% +want me to erase it guys don't seriously + + + align:start position:0% +want me to erase it guys don't seriously +i want you to get the point of what i'm + + align:start position:0% +i want you to get the point of what i'm + + + align:start position:0% +i want you to get the point of what i'm +saying right i'll give this to you + + align:start position:0% +saying right i'll give this to you + + + align:start position:0% +saying right i'll give this to you +promise promise you we will scan it and + + align:start position:0% +promise promise you we will scan it and + + + align:start position:0% +promise promise you we will scan it and +post it if it's already written down + + align:start position:0% +post it if it's already written down + + + align:start position:0% +post it if it's already written down +right we'll post it for you on the web + + align:start position:0% +right we'll post it for you on the web + + + align:start position:0% +right we'll post it for you on the web +so you can read it okay + + align:start position:0% +so you can read it okay + + + align:start position:0% +so you can read it okay +writing it down it won't add a lot for + + align:start position:0% +writing it down it won't add a lot for + + + align:start position:0% +writing it down it won't add a lot for +this you should write all the other + + align:start position:0% +this you should write all the other + + + align:start position:0% +this you should write all the other +stuff i doubt i say and do down but not + + align:start position:0% +stuff i doubt i say and do down but not + + + align:start position:0% +stuff i doubt i say and do down but not +this + + align:start position:0% +this + + + align:start position:0% +this +okay + + align:start position:0% +okay + + + align:start position:0% +okay +um + + align:start position:0% +um + + + align:start position:0% +um +but you can stare at it but don't write + + align:start position:0% +but you can stare at it but don't write + + + align:start position:0% +but you can stare at it but don't write +it down because we'll give it to you + + align:start position:0% +it down because we'll give it to you + + + align:start position:0% +it down because we'll give it to you +point i'm making is a very simple one + + align:start position:0% +point i'm making is a very simple one + + + align:start position:0% +point i'm making is a very simple one +right + + align:start position:0% +right + + + align:start position:0% +right +torque is equal to i alpha for rigid + + align:start position:0% +torque is equal to i alpha for rigid + + + align:start position:0% +torque is equal to i alpha for rigid +bodies that's all i'm trying to say okay + + align:start position:0% +bodies that's all i'm trying to say okay + + + align:start position:0% +bodies that's all i'm trying to say okay +and really this is all just boring math + + align:start position:0% +and really this is all just boring math + + + align:start position:0% +and really this is all just boring math +this is the result i want you to see + + align:start position:0% +this is the result i want you to see + + + align:start position:0% +this is the result i want you to see +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and i didn't cheat i just did all from + + align:start position:0% +and i didn't cheat i just did all from + + + align:start position:0% +and i didn't cheat i just did all from +my physical dna + + align:start position:0% +my physical dna + + + align:start position:0% +my physical dna +all right so what we're going to do now + + align:start position:0% +all right so what we're going to do now + + + align:start position:0% +all right so what we're going to do now +is + + align:start position:0% +is + + + align:start position:0% +is +we're going to look at + + align:start position:0% + + + + align:start position:0% + +multiple particles like that in one shot + + align:start position:0% +multiple particles like that in one shot + + + align:start position:0% +multiple particles like that in one shot +so + + align:start position:0% +so + + + align:start position:0% +so +first consider + + align:start position:0% +first consider + + + align:start position:0% +first consider +again a frame of reference a + + align:start position:0% + + + + align:start position:0% + +and this is point o + + align:start position:0% +and this is point o + + + align:start position:0% +and this is point o +consider + + align:start position:0% +consider + + + align:start position:0% +consider +a particle i + + align:start position:0% +a particle i + + + align:start position:0% +a particle i +a particle j + + align:start position:0% +a particle j + + + align:start position:0% +a particle j +and thousands millions + + align:start position:0% +and thousands millions + + + align:start position:0% +and thousands millions +of other particles + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +now + + align:start position:0% +now + + + align:start position:0% +now +on each particle i or j + + align:start position:0% +on each particle i or j + + + align:start position:0% +on each particle i or j +there is a force + + align:start position:0% +there is a force + + + align:start position:0% +there is a force +which i'm going to write + + align:start position:0% +which i'm going to write + + + align:start position:0% +which i'm going to write +subscript of the superscript i + + align:start position:0% +subscript of the superscript i + + + align:start position:0% +subscript of the superscript i +little f which is the force on i + + align:start position:0% +little f which is the force on i + + + align:start position:0% +little f which is the force on i +and there's a force on j + + align:start position:0% +and there's a force on j + + + align:start position:0% +and there's a force on j +which is + + align:start position:0% +which is + + + align:start position:0% +which is +j + + align:start position:0% +j + + + align:start position:0% +j +that's the force on j + + align:start position:0% +that's the force on j + + + align:start position:0% +that's the force on j +okay and each particle has a position + + align:start position:0% +okay and each particle has a position + + + align:start position:0% +okay and each particle has a position +vector o i r o i and r o j + + align:start position:0% +vector o i r o i and r o j + + + align:start position:0% +vector o i r o i and r o j +okay same thing x i'm now going to do it + + align:start position:0% +okay same thing x i'm now going to do it + + + align:start position:0% +okay same thing x i'm now going to do it +in a general way + + align:start position:0% +in a general way + + + align:start position:0% +in a general way +now first you need to tell + + align:start position:0% + + + + align:start position:0% + +me what is + + align:start position:0% + + + + align:start position:0% + +how is fi related to + + align:start position:0% +how is fi related to + + + align:start position:0% +how is fi related to +the acceleration of particle i + + align:start position:0% + + + + align:start position:0% + +anybody + + align:start position:0% + + + + align:start position:0% + +is that right + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +uh + + align:start position:0% +uh + + + align:start position:0% +uh +actually let's not assume that thank you + + align:start position:0% + + + + align:start position:0% + +m i ai + + align:start position:0% +m i ai + + + align:start position:0% +m i ai +right that's the acceleration of + + align:start position:0% +right that's the acceleration of + + + align:start position:0% +right that's the acceleration of +particle a + + align:start position:0% +particle a + + + align:start position:0% +particle a +or i right + + align:start position:0% +or i right + + + align:start position:0% +or i right +what is the uh + + align:start position:0% +what is the uh + + + align:start position:0% +what is the uh +torque on particle i let's pick a point + + align:start position:0% +torque on particle i let's pick a point + + + align:start position:0% +torque on particle i let's pick a point +q + + align:start position:0% +q + + + align:start position:0% +q +we'll call this the reference point for + + align:start position:0% +we'll call this the reference point for + + + align:start position:0% +we'll call this the reference point for +torques + + align:start position:0% +torques + + + align:start position:0% +torques +what is the torque on particle i + + align:start position:0% +what is the torque on particle i + + + align:start position:0% +what is the torque on particle i +and how is that related to its motion + + align:start position:0% +and how is that related to its motion + + + align:start position:0% +and how is that related to its motion +anybody + + align:start position:0% + + + + align:start position:0% + +sorry + + align:start position:0% + + + + align:start position:0% + +yeah so that's the definition of torque + + align:start position:0% +yeah so that's the definition of torque + + + align:start position:0% +yeah so that's the definition of torque +what's the angular momentum type thing + + align:start position:0% +what's the angular momentum type thing + + + align:start position:0% +what's the angular momentum type thing +it's just going to be the formula i + + align:start position:0% +it's just going to be the formula i + + + align:start position:0% +it's just going to be the formula i +didn't ask the question clearly it's + + align:start position:0% +didn't ask the question clearly it's + + + align:start position:0% +didn't ask the question clearly it's +just going to be this formula + + align:start position:0% + + + + align:start position:0% + +sorry + + align:start position:0% + + + + align:start position:0% + +right these are the two + + align:start position:0% + + + + align:start position:0% + +these are the two + + align:start position:0% +these are the two + + + align:start position:0% +these are the two +statements we can make about those two + + align:start position:0% +statements we can make about those two + + + align:start position:0% +statements we can make about those two +particles right + + align:start position:0% +particles right + + + align:start position:0% +particles right +yes + + align:start position:0% +yes + + + align:start position:0% +yes +okay + + align:start position:0% +okay + + + align:start position:0% +okay +now + + align:start position:0% + + + + align:start position:0% + +what happens when you have multiple + + align:start position:0% +what happens when you have multiple + + + align:start position:0% +what happens when you have multiple +particles + + align:start position:0% +particles + + + align:start position:0% +particles +i j k + + align:start position:0% +i j k + + + align:start position:0% +i j k +1 to in you know 300 million + + align:start position:0% +1 to in you know 300 million + + + align:start position:0% +1 to in you know 300 million +n + + align:start position:0% +n + + + align:start position:0% +n +how do those equations work + + align:start position:0% +how do those equations work + + + align:start position:0% +how do those equations work +look at these two look look what + + align:start position:0% +look at these two look look what + + + align:start position:0% +look at these two look look what +happened here what happens in your + + align:start position:0% +happened here what happens in your + + + align:start position:0% +happened here what happens in your +multiple particles + + align:start position:0% +multiple particles + + + align:start position:0% +multiple particles +anybody + + align:start position:0% + + + + align:start position:0% + +say it again + + align:start position:0% +say it again + + + align:start position:0% +say it again +oh let's do it that's right this should + + align:start position:0% +oh let's do it that's right this should + + + align:start position:0% +oh let's do it that's right this should +be q is that what you're saying yeah + + align:start position:0% +be q is that what you're saying yeah + + + align:start position:0% +be q is that what you're saying yeah +thank you that should be q + + align:start position:0% +thank you that should be q + + + align:start position:0% +thank you that should be q +reference point + + align:start position:0% + + + + align:start position:0% + +now what happens in the multiple points + + align:start position:0% +now what happens in the multiple points + + + align:start position:0% +now what happens in the multiple points +take a guess what's the equation going + + align:start position:0% +take a guess what's the equation going + + + align:start position:0% +take a guess what's the equation going +to look at for multiple points + + align:start position:0% +to look at for multiple points + + + align:start position:0% +to look at for multiple points +anybody + + align:start position:0% + + + + align:start position:0% + +let me + + align:start position:0% +let me + + + align:start position:0% +let me +say it's going to look the same + + align:start position:0% +say it's going to look the same + + + align:start position:0% +say it's going to look the same +what's now by the way i'm going to call + + align:start position:0% +what's now by the way i'm going to call + + + align:start position:0% +what's now by the way i'm going to call +this entire set of points + + align:start position:0% +this entire set of points + + + align:start position:0% +this entire set of points +all of them i'm going to call them the + + align:start position:0% +all of them i'm going to call them the + + + align:start position:0% +all of them i'm going to call them the +ensemble e so when i say e i'm referring + + align:start position:0% +ensemble e so when i say e i'm referring + + + align:start position:0% +ensemble e so when i say e i'm referring +to the entire set of points because i + + align:start position:0% +to the entire set of points because i + + + align:start position:0% +to the entire set of points because i +need a term for it all right so here's + + align:start position:0% +need a term for it all right so here's + + + align:start position:0% +need a term for it all right so here's +what we're going + + align:start position:0% +what we're going + + + align:start position:0% +what we're going +to end up + + align:start position:0% +to end up + + + align:start position:0% +to end up +the total force on the ensemble the + + align:start position:0% +the total force on the ensemble the + + + align:start position:0% +the total force on the ensemble the +total external force on the ensemble + + align:start position:0% +total external force on the ensemble + + + align:start position:0% +total external force on the ensemble +is equal to + + align:start position:0% +is equal to + + + align:start position:0% +is equal to +the mass of the ensemble where the mass + + align:start position:0% +the mass of the ensemble where the mass + + + align:start position:0% +the mass of the ensemble where the mass +of the ensemble is sigma mi so it's the + + align:start position:0% +of the ensemble is sigma mi so it's the + + + align:start position:0% +of the ensemble is sigma mi so it's the +sum of all the masses + + align:start position:0% +sum of all the masses + + + align:start position:0% +sum of all the masses +times + + align:start position:0% +times + + + align:start position:0% +times +the acceleration + + align:start position:0% +the acceleration + + + align:start position:0% +the acceleration +of the ensemble + + align:start position:0% +of the ensemble + + + align:start position:0% +of the ensemble +that's right the center of mass of the + + align:start position:0% +that's right the center of mass of the + + + align:start position:0% +that's right the center of mass of the +ensemble that's where we're going to end + + align:start position:0% +ensemble that's where we're going to end + + + align:start position:0% +ensemble that's where we're going to end +up + + align:start position:0% +up + + + align:start position:0% +up +all right + + align:start position:0% +all right + + + align:start position:0% +all right +the center of mass + + align:start position:0% +the center of mass + + + align:start position:0% +the center of mass +and i'm going to write it like this + + align:start position:0% +and i'm going to write it like this + + + align:start position:0% +and i'm going to write it like this +all right just right now for emphasis + + align:start position:0% +all right just right now for emphasis + + + align:start position:0% +all right just right now for emphasis +i'm going to say the center of mass of + + align:start position:0% +i'm going to say the center of mass of + + + align:start position:0% +i'm going to say the center of mass of +that ensemble + + align:start position:0% +that ensemble + + + align:start position:0% +that ensemble +when i say c subscript e it's the center + + align:start position:0% +when i say c subscript e it's the center + + + align:start position:0% +when i say c subscript e it's the center +of mass of that ensemble + + align:start position:0% +of mass of that ensemble + + + align:start position:0% +of mass of that ensemble +okay after some time i'll get lazy and + + align:start position:0% +okay after some time i'll get lazy and + + + align:start position:0% +okay after some time i'll get lazy and +i'll stop writing the e it'll just be c + + align:start position:0% +i'll stop writing the e it'll just be c + + + align:start position:0% +i'll stop writing the e it'll just be c +when you see a c assume it's the center + + align:start position:0% +when you see a c assume it's the center + + + align:start position:0% +when you see a c assume it's the center +of mass of the ensemble i'll try and + + align:start position:0% +of mass of the ensemble i'll try and + + + align:start position:0% +of mass of the ensemble i'll try and +keep it up as long as i can + + align:start position:0% +keep it up as long as i can + + + align:start position:0% +keep it up as long as i can +and you know what else we're going to + + align:start position:0% +and you know what else we're going to + + + align:start position:0% +and you know what else we're going to +find + + align:start position:0% +find + + + align:start position:0% +find +we're gonna find + + align:start position:0% +we're gonna find + + + align:start position:0% +we're gonna find +the torque + + align:start position:0% +the torque + + + align:start position:0% +the torque +on the ensemble + + align:start position:0% + + + + align:start position:0% + +about point q which is the sum of all + + align:start position:0% +about point q which is the sum of all + + + align:start position:0% +about point q which is the sum of all +the torques about all the points + + align:start position:0% +the torques about all the points + + + align:start position:0% +the torques about all the points +about point q we're gonna find this i'm + + align:start position:0% +about point q we're gonna find this i'm + + + align:start position:0% +about point q we're gonna find this i'm +just giving a heads up is equal to + + align:start position:0% + + + + align:start position:0% + +a + + align:start position:0% +a + + + align:start position:0% +a +it's going to look very similar to what + + align:start position:0% +it's going to look very similar to what + + + align:start position:0% +it's going to look very similar to what +we have there d by dt + + align:start position:0% +we have there d by dt + + + align:start position:0% +we have there d by dt +a + + align:start position:0% +a + + + align:start position:0% +a +h + + align:start position:0% +h + + + align:start position:0% +h +when i write a capital + + align:start position:0% +when i write a capital + + + align:start position:0% +when i write a capital +is the total right the total torque not + + align:start position:0% +is the total right the total torque not + + + align:start position:0% +is the total right the total torque not +tau + + align:start position:0% +tau + + + align:start position:0% +tau +the total force not little force it's + + align:start position:0% +the total force not little force it's + + + align:start position:0% +the total force not little force it's +the total angular momentum + + align:start position:0% +the total angular momentum + + + align:start position:0% +the total angular momentum +of the entire ensemble + + align:start position:0% +of the entire ensemble + + + align:start position:0% +of the entire ensemble +about point q + + align:start position:0% +about point q + + + align:start position:0% +about point q +plus + + align:start position:0% +plus + + + align:start position:0% +plus +a + + align:start position:0% +a + + + align:start position:0% +a +v q + + align:start position:0% +v q + + + align:start position:0% +v q +cross what's this term going to be + + align:start position:0% +cross what's this term going to be + + + align:start position:0% +cross what's this term going to be +what's the equivalent here going to be + + align:start position:0% + + + + align:start position:0% + +say it again + + align:start position:0% +say it again + + + align:start position:0% +say it again +yeah capital p what's the reference + + align:start position:0% +yeah capital p what's the reference + + + align:start position:0% +yeah capital p what's the reference +frame + + align:start position:0% +frame + + + align:start position:0% +frame +a + + align:start position:0% +a + + + align:start position:0% +a +and what what is it the angle the linear + + align:start position:0% +and what what is it the angle the linear + + + align:start position:0% +and what what is it the angle the linear +momentum off + + align:start position:0% + + + + align:start position:0% + +the center of mass of the ensemble now + + align:start position:0% +the center of mass of the ensemble now + + + align:start position:0% +the center of mass of the ensemble now +as it turns out in this one case + + align:start position:0% +as it turns out in this one case + + + align:start position:0% +as it turns out in this one case +center of mass of the ons the momentum + + align:start position:0% +center of mass of the ons the momentum + + + align:start position:0% +center of mass of the ons the momentum +of the center of mass of the ensemble is + + align:start position:0% +of the center of mass of the ensemble is + + + align:start position:0% +of the center of mass of the ensemble is +the same as the total momentum of the + + align:start position:0% +the same as the total momentum of the + + + align:start position:0% +the same as the total momentum of the +ensemble + + align:start position:0% +ensemble + + + align:start position:0% +ensemble +got it + + align:start position:0% +got it + + + align:start position:0% +got it +so this is simply going to be + + align:start position:0% + + + + align:start position:0% + +this + + align:start position:0% +this + + + align:start position:0% +this +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so this is what we're gonna do + + align:start position:0% +so this is what we're gonna do + + + align:start position:0% +so this is what we're gonna do +this is what you've seen + + align:start position:0% +this is what you've seen + + + align:start position:0% +this is what you've seen +this is we're gonna go to and then by + + align:start position:0% +this is we're gonna go to and then by + + + align:start position:0% +this is we're gonna go to and then by +the way + + align:start position:0% +the way + + + align:start position:0% +the way +we will show that under certain + + align:start position:0% +we will show that under certain + + + align:start position:0% +we will show that under certain +circumstances + + align:start position:0% +circumstances + + + align:start position:0% +circumstances +this reduces to + + align:start position:0% +this reduces to + + + align:start position:0% +this reduces to +i alpha + + align:start position:0% +i alpha + + + align:start position:0% +i alpha +and really these are the two equations + + align:start position:0% +and really these are the two equations + + + align:start position:0% +and really these are the two equations +we seek these two + + align:start position:0% + + + + align:start position:0% + +okay so that's the roadmap we're going + + align:start position:0% +okay so that's the roadmap we're going + + + align:start position:0% +okay so that's the roadmap we're going +to follow + + align:start position:0% +to follow + + + align:start position:0% +to follow +got it + + align:start position:0% + + + + align:start position:0% + +this equation we're going to turn into + + align:start position:0% +this equation we're going to turn into + + + align:start position:0% +this equation we're going to turn into +this guy + + align:start position:0% +this guy + + + align:start position:0% +this guy +this equation we're going to turn to + + align:start position:0% +this equation we're going to turn to + + + align:start position:0% +this equation we're going to turn to +this guy + + align:start position:0% +this guy + + + align:start position:0% +this guy +under certain circumstances this + + align:start position:0% +under certain circumstances this + + + align:start position:0% +under certain circumstances this +equation + + align:start position:0% +equation + + + align:start position:0% +equation +becomes i alpha + + align:start position:0% +becomes i alpha + + + align:start position:0% +becomes i alpha +and we're done + + align:start position:0% +and we're done + + + align:start position:0% +and we're done +that's what we're going to do now any + + align:start position:0% +that's what we're going to do now any + + + align:start position:0% +that's what we're going to do now any +questions + + align:start position:0% +questions + + + align:start position:0% +questions +i insist on at least one question at + + align:start position:0% +i insist on at least one question at + + + align:start position:0% +i insist on at least one question at +this point + + align:start position:0% +this point + + + align:start position:0% +this point +i'm feeling + + align:start position:0% +i'm feeling + + + align:start position:0% +i'm feeling +unquestioned i need to be questioned + + align:start position:0% +unquestioned i need to be questioned + + + align:start position:0% +unquestioned i need to be questioned +yes thank you + + align:start position:0% + + + + align:start position:0% + +that's what we're going to do now so + + align:start position:0% +that's what we're going to do now so + + + align:start position:0% +that's what we're going to do now so +this is that's where we're going to go + + align:start position:0% +this is that's where we're going to go + + + align:start position:0% +this is that's where we're going to go +and what i'm going to do is i'm going to + + align:start position:0% +and what i'm going to do is i'm going to + + + align:start position:0% +and what i'm going to do is i'm going to +take you there + + align:start position:0% +take you there + + + align:start position:0% +take you there +i'm going to show you these results good + + align:start position:0% +i'm going to show you these results good + + + align:start position:0% +i'm going to show you these results good +question okay + + align:start position:0% +question okay + + + align:start position:0% +question okay +so + + align:start position:0% +so + + + align:start position:0% +so +what we're going to do now + + align:start position:0% +what we're going to do now + + + align:start position:0% +what we're going to do now +is derive this + + align:start position:0% +is derive this + + + align:start position:0% +is derive this +derive this then we'll divide this and + + align:start position:0% +derive this then we'll divide this and + + + align:start position:0% +derive this then we'll divide this and +then we'll divide this + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so let's derive this first + + align:start position:0% +so let's derive this first + + + align:start position:0% +so let's derive this first +in order for me to derive that the first + + align:start position:0% +in order for me to derive that the first + + + align:start position:0% +in order for me to derive that the first +thing i need to do i need to do + + align:start position:0% +thing i need to do i need to do + + + align:start position:0% +thing i need to do i need to do +is i need to introduce + + align:start position:0% +is i need to introduce + + + align:start position:0% +is i need to introduce +the concept of a center of mass + + align:start position:0% +the concept of a center of mass + + + align:start position:0% +the concept of a center of mass +officially you've seen it unofficially + + align:start position:0% +officially you've seen it unofficially + + + align:start position:0% +officially you've seen it unofficially +but i need to do it officially + + align:start position:0% +but i need to do it officially + + + align:start position:0% +but i need to do it officially +okay + + align:start position:0% +okay + + + align:start position:0% +okay +if i have an ensemble can anyone tell me + + align:start position:0% +if i have an ensemble can anyone tell me + + + align:start position:0% +if i have an ensemble can anyone tell me +the definition + + align:start position:0% +the definition + + + align:start position:0% +the definition +of the center of mass of the ensemble + + align:start position:0% +of the center of mass of the ensemble + + + align:start position:0% +of the center of mass of the ensemble +take a guess + + align:start position:0% + + + + align:start position:0% + +i'll say it in english and let's see if + + align:start position:0% +i'll say it in english and let's see if + + + align:start position:0% +i'll say it in english and let's see if +you can put it in formulae + + align:start position:0% +you can put it in formulae + + + align:start position:0% +you can put it in formulae +it is the weighted average + + align:start position:0% +it is the weighted average + + + align:start position:0% +it is the weighted average +mass weighted average of the position + + align:start position:0% +mass weighted average of the position + + + align:start position:0% +mass weighted average of the position +vectors of all the individual particles + + align:start position:0% +vectors of all the individual particles + + + align:start position:0% +vectors of all the individual particles +right does that make sense in english + + align:start position:0% +right does that make sense in english + + + align:start position:0% +right does that make sense in english +yes + + align:start position:0% + + + + align:start position:0% + +here let me tell you how to do it right + + align:start position:0% +here let me tell you how to do it right + + + align:start position:0% +here let me tell you how to do it right +i'm just going to write it down + + align:start position:0% +i'm just going to write it down + + + align:start position:0% +i'm just going to write it down +and you'll see it's correct + + align:start position:0% +and you'll see it's correct + + + align:start position:0% +and you'll see it's correct +you by the way this you need to get + + align:start position:0% + + + + align:start position:0% + +you're exactly right by the way but the + + align:start position:0% +you're exactly right by the way but the + + + align:start position:0% +you're exactly right by the way but the +only thing i'll defer with is you don't + + align:start position:0% +only thing i'll defer with is you don't + + + align:start position:0% +only thing i'll defer with is you don't +have to do it separately you can do it + + align:start position:0% +have to do it separately you can do it + + + align:start position:0% +have to do it separately you can do it +in one vector form + + align:start position:0% +in one vector form + + + align:start position:0% +in one vector form +let me explain + + align:start position:0% +let me explain + + + align:start position:0% +let me explain +here look + + align:start position:0% + + + + align:start position:0% + +this forks is the center of mass + + align:start position:0% +this forks is the center of mass + + + align:start position:0% +this forks is the center of mass +take every vector of every particle + + align:start position:0% +take every vector of every particle + + + align:start position:0% +take every vector of every particle +right + + align:start position:0% +right + + + align:start position:0% +right +multiplied by its mass + + align:start position:0% +multiplied by its mass + + + align:start position:0% +multiplied by its mass +add the whole thing up + + align:start position:0% +add the whole thing up + + + align:start position:0% +add the whole thing up +divided by the total mass the vector + + align:start position:0% +divided by the total mass the vector + + + align:start position:0% +divided by the total mass the vector +that comes out it's some sort of mean + + align:start position:0% +that comes out it's some sort of mean + + + align:start position:0% +that comes out it's some sort of mean +vector + + align:start position:0% +vector + + + align:start position:0% +vector +that is the vector of the center of mass + + align:start position:0% +that is the vector of the center of mass + + + align:start position:0% +that is the vector of the center of mass +see what i mean and in fact you were + + align:start position:0% +see what i mean and in fact you were + + + align:start position:0% +see what i mean and in fact you were +right in principle i mean in practice + + align:start position:0% +right in principle i mean in practice + + + align:start position:0% +right in principle i mean in practice +you might do it in in coordinates but + + align:start position:0% +you might do it in in coordinates but + + + align:start position:0% +you might do it in in coordinates but +you can write this way so now here i'm + + align:start position:0% +you can write this way so now here i'm + + + align:start position:0% +you can write this way so now here i'm +going to stop and ask you does anyone + + align:start position:0% +going to stop and ask you does anyone + + + align:start position:0% +going to stop and ask you does anyone +have any questions about this + + align:start position:0% +have any questions about this + + + align:start position:0% +have any questions about this +i've simply written an age-old concept + + align:start position:0% +i've simply written an age-old concept + + + align:start position:0% +i've simply written an age-old concept +things you've seen in high school + + align:start position:0% +things you've seen in high school + + + align:start position:0% +things you've seen in high school +in vector form and do you get it + + align:start position:0% + + + + align:start position:0% + +you twitched + + align:start position:0% +you twitched + + + align:start position:0% +you twitched +was that just doing this or did you have + + align:start position:0% +was that just doing this or did you have + + + align:start position:0% +was that just doing this or did you have +a question + + align:start position:0% +a question + + + align:start position:0% +a question +just kidding anyone + + align:start position:0% + + + + align:start position:0% + +do you understand this + + align:start position:0% +do you understand this + + + align:start position:0% +do you understand this +if you don't if you think i went fast + + align:start position:0% +if you don't if you think i went fast + + + align:start position:0% +if you don't if you think i went fast +and you want me to say this again i'll + + align:start position:0% +and you want me to say this again i'll + + + align:start position:0% +and you want me to say this again i'll +say it again + + align:start position:0% +say it again + + + align:start position:0% +say it again +who wants me to say this again + + align:start position:0% +who wants me to say this again + + + align:start position:0% +who wants me to say this again +anyone + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +that is the central mass + + align:start position:0% +that is the central mass + + + align:start position:0% +that is the central mass +it is again take every vector every + + align:start position:0% +it is again take every vector every + + + align:start position:0% +it is again take every vector every +position vector + + align:start position:0% +position vector + + + align:start position:0% +position vector +multiplied by the mass of that particle + + align:start position:0% +multiplied by the mass of that particle + + + align:start position:0% +multiplied by the mass of that particle +add up all this ensemble you know + + align:start position:0% +add up all this ensemble you know + + + align:start position:0% +add up all this ensemble you know +position vectors weighted and divided by + + align:start position:0% +position vectors weighted and divided by + + + align:start position:0% +position vectors weighted and divided by +the total mass boom + + align:start position:0% +the total mass boom + + + align:start position:0% +the total mass boom +it's the average position vector got it + + align:start position:0% +it's the average position vector got it + + + align:start position:0% +it's the average position vector got it +okay + + align:start position:0% + + + + align:start position:0% + +now + + align:start position:0% + + + + align:start position:0% + +if i wanted to find the velocity + + align:start position:0% +if i wanted to find the velocity + + + align:start position:0% +if i wanted to find the velocity +of the center of mass it would be this i + + align:start position:0% +of the center of mass it would be this i + + + align:start position:0% +of the center of mass it would be this i +would write it as this + + align:start position:0% + + + + align:start position:0% + +i'm only doing this because in the end + + align:start position:0% +i'm only doing this because in the end + + + align:start position:0% +i'm only doing this because in the end +we'll need an acceleration of the center + + align:start position:0% +we'll need an acceleration of the center + + + align:start position:0% +we'll need an acceleration of the center +of mass right so i'm going to take the + + align:start position:0% +of mass right so i'm going to take the + + + align:start position:0% +of mass right so i'm going to take the +first derivative and i'll write it for + + align:start position:0% +first derivative and i'll write it for + + + align:start position:0% +first derivative and i'll write it for +you and you'll see that there's no great + + align:start position:0% +you and you'll see that there's no great + + + align:start position:0% +you and you'll see that there's no great +magic here + + align:start position:0% +magic here + + + align:start position:0% +magic here +it'll come out to be simply + + align:start position:0% + + + + align:start position:0% + +by the way we can expand this summation + + align:start position:0% +by the way we can expand this summation + + + align:start position:0% +by the way we can expand this summation +it's i is equal to one + + align:start position:0% +it's i is equal to one + + + align:start position:0% +it's i is equal to one +if there are n particles of summation + + align:start position:0% +if there are n particles of summation + + + align:start position:0% +if there are n particles of summation +the summation i is equal to one through + + align:start position:0% +the summation i is equal to one through + + + align:start position:0% +the summation i is equal to one through +n + + align:start position:0% +n + + + align:start position:0% +n +off + + align:start position:0% +off + + + align:start position:0% +off +m i + + align:start position:0% + + + + align:start position:0% + +can anyone tell me what the velocity is + + align:start position:0% +can anyone tell me what the velocity is + + + align:start position:0% +can anyone tell me what the velocity is +going to be at the center of mass + + align:start position:0% +going to be at the center of mass + + + align:start position:0% +going to be at the center of mass +for the position vector to take the the + + align:start position:0% +for the position vector to take the the + + + align:start position:0% +for the position vector to take the the +weighted average of the position vectors + + align:start position:0% +weighted average of the position vectors + + + align:start position:0% +weighted average of the position vectors +for the velocity what do i need to take + + align:start position:0% +for the velocity what do i need to take + + + align:start position:0% +for the velocity what do i need to take +excellent + + align:start position:0% + + + + align:start position:0% + +i'm going to replace this ensemble + + align:start position:0% +i'm going to replace this ensemble + + + align:start position:0% +i'm going to replace this ensemble +summation + + align:start position:0% +summation + + + align:start position:0% +summation +with just this term which means the mass + + align:start position:0% +with just this term which means the mass + + + align:start position:0% +with just this term which means the mass +of the ensemble + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and finally + + align:start position:0% +and finally + + + align:start position:0% +and finally +if i want the acceleration of the center + + align:start position:0% +if i want the acceleration of the center + + + align:start position:0% +if i want the acceleration of the center +of mass + + align:start position:0% + + + + align:start position:0% + +it's going to be what the weighted + + align:start position:0% +it's going to be what the weighted + + + align:start position:0% +it's going to be what the weighted +average of the + + align:start position:0% +average of the + + + align:start position:0% +average of the +accelerations of the individual + + align:start position:0% +accelerations of the individual + + + align:start position:0% +accelerations of the individual +particles + + align:start position:0% + + + + align:start position:0% + +make sense + + align:start position:0% + + + + align:start position:0% + +now i'm going to raise this only because + + align:start position:0% +now i'm going to raise this only because + + + align:start position:0% +now i'm going to raise this only because +i need some room + + align:start position:0% + + + + align:start position:0% + +so now i've told you what central mass + + align:start position:0% +so now i've told you what central mass + + + align:start position:0% +so now i've told you what central mass +is + + align:start position:0% + + + + align:start position:0% + +ajay can you publish the handwritten + + align:start position:0% +ajay can you publish the handwritten + + + align:start position:0% +ajay can you publish the handwritten +dumbbell problem if you just scan your + + align:start position:0% +dumbbell problem if you just scan your + + + align:start position:0% +dumbbell problem if you just scan your +notes + + align:start position:0% +notes + + + align:start position:0% +notes +thanks + + align:start position:0% +thanks + + + align:start position:0% +thanks +all right that's the center of mass + + align:start position:0% +all right that's the center of mass + + + align:start position:0% +all right that's the center of mass +stuff okay now you understand center of + + align:start position:0% +stuff okay now you understand center of + + + align:start position:0% +stuff okay now you understand center of +mass + + align:start position:0% +mass + + + align:start position:0% +mass +uh i i remember when someone asked me + + align:start position:0% +uh i i remember when someone asked me + + + align:start position:0% +uh i i remember when someone asked me +you know where that a acceleration c + + align:start position:0% +you know where that a acceleration c + + + align:start position:0% +you know where that a acceleration c +came from + + align:start position:0% +came from + + + align:start position:0% +came from +right there were two ways to do it the + + align:start position:0% +right there were two ways to do it the + + + align:start position:0% +right there were two ways to do it the +ajay way which is to expand it and just + + align:start position:0% +ajay way which is to expand it and just + + + align:start position:0% +ajay way which is to expand it and just +show that it comes out to be that + + align:start position:0% +show that it comes out to be that + + + align:start position:0% +show that it comes out to be that +but my explanation was actually + + align:start position:0% + + + + align:start position:0% + +i was kind of alluding to this + + align:start position:0% +i was kind of alluding to this + + + align:start position:0% +i was kind of alluding to this +you understand + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +now + + align:start position:0% +now + + + align:start position:0% +now +let's take this guy + + align:start position:0% +let's take this guy + + + align:start position:0% +let's take this guy +and summit + + align:start position:0% +and summit + + + align:start position:0% +and summit +for the entire ensemble of particles + + align:start position:0% +for the entire ensemble of particles + + + align:start position:0% +for the entire ensemble of particles +okay + + align:start position:0% + + + + align:start position:0% + +that's just simply that equation summed + + align:start position:0% +that's just simply that equation summed + + + align:start position:0% +that's just simply that equation summed +up for the entire ensemble of particles + + align:start position:0% +up for the entire ensemble of particles + + + align:start position:0% +up for the entire ensemble of particles +right + + align:start position:0% +right + + + align:start position:0% +right +right + + align:start position:0% +right + + + align:start position:0% +right +everyone + + align:start position:0% +everyone + + + align:start position:0% +everyone +yes + + align:start position:0% + + + + align:start position:0% + +uh you know that's the same thing + + align:start position:0% +uh you know that's the same thing + + + align:start position:0% +uh you know that's the same thing +believe it or not + + align:start position:0% +believe it or not + + + align:start position:0% +believe it or not +in fact that's so think of it that's + + align:start position:0% +in fact that's so think of it that's + + + align:start position:0% +in fact that's so think of it that's +actually + + align:start position:0% +actually + + + align:start position:0% +actually +um i'm glad you're asking that question + + align:start position:0% +um i'm glad you're asking that question + + + align:start position:0% +um i'm glad you're asking that question +because it's good it's important to + + align:start position:0% +because it's good it's important to + + + align:start position:0% +because it's good it's important to +think about it those are not different + + align:start position:0% +think about it those are not different + + + align:start position:0% +think about it those are not different +things they're not incompatible if you + + align:start position:0% +things they're not incompatible if you + + + align:start position:0% +things they're not incompatible if you +remove this it's an individual particle + + align:start position:0% +remove this it's an individual particle + + + align:start position:0% +remove this it's an individual particle +get it + + align:start position:0% +get it + + + align:start position:0% +get it +and then when you sum it you're just + + align:start position:0% +and then when you sum it you're just + + + align:start position:0% +and then when you sum it you're just +saying this individual particle plus + + align:start position:0% +saying this individual particle plus + + + align:start position:0% +saying this individual particle plus +this individual particle plus this + + align:start position:0% +this individual particle plus this + + + align:start position:0% +this individual particle plus this +individual particle a counter is simply + + align:start position:0% +individual particle a counter is simply + + + align:start position:0% +individual particle a counter is simply +saying consider each individual particle + + align:start position:0% +saying consider each individual particle + + + align:start position:0% +saying consider each individual particle +and then do repeat until it's like + + align:start position:0% +and then do repeat until it's like + + + align:start position:0% +and then do repeat until it's like +writing a program + + align:start position:0% +writing a program + + + align:start position:0% +writing a program +get it + + align:start position:0% +get it + + + align:start position:0% +get it +everyone understand this + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +so where does this lead us + + align:start position:0% + + + + align:start position:0% + +what is this written as + + align:start position:0% + + + + align:start position:0% + +what + + align:start position:0% + + + + align:start position:0% + +the total force on the ensemble + + align:start position:0% +the total force on the ensemble + + + align:start position:0% +the total force on the ensemble +capital f + + align:start position:0% +capital f + + + align:start position:0% +capital f +e + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +what is th + + align:start position:0% +what is th + + + align:start position:0% +what is th +and what is this + + align:start position:0% +and what is this + + + align:start position:0% +and what is this +look up there + + align:start position:0% +look up there + + + align:start position:0% +look up there +what is this right hand side + + align:start position:0% + + + + align:start position:0% + +that's correct + + align:start position:0% +that's correct + + + align:start position:0% +that's correct +so we have that first result + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so f e is equal to m e times the + + align:start position:0% +so f e is equal to m e times the + + + align:start position:0% +so f e is equal to m e times the +acceleration that's the first result + + align:start position:0% +acceleration that's the first result + + + align:start position:0% +acceleration that's the first result +we've just proved it + + align:start position:0% +we've just proved it + + + align:start position:0% +we've just proved it +it's very simple i just took the + + align:start position:0% +it's very simple i just took the + + + align:start position:0% +it's very simple i just took the +equation of the motion for each + + align:start position:0% +equation of the motion for each + + + align:start position:0% +equation of the motion for each +particular added them up i use + + align:start position:0% +particular added them up i use + + + align:start position:0% +particular added them up i use +the definition of central message is + + align:start position:0% +the definition of central message is + + + align:start position:0% +the definition of central message is +what i get + + align:start position:0% +what i get + + + align:start position:0% +what i get +okay + + align:start position:0% +okay + + + align:start position:0% +okay +it's just a nice way to do that once and + + align:start position:0% +it's just a nice way to do that once and + + + align:start position:0% +it's just a nice way to do that once and +for all and we're done + + align:start position:0% +for all and we're done + + + align:start position:0% +for all and we're done +two quick questions for you first + + align:start position:0% +two quick questions for you first + + + align:start position:0% +two quick questions for you first +question + + align:start position:0% +question + + + align:start position:0% +question +does this assume + + align:start position:0% +does this assume + + + align:start position:0% +does this assume +that the particles are connected or + + align:start position:0% +that the particles are connected or + + + align:start position:0% +that the particles are connected or +rigid did i make that assumption + + align:start position:0% +rigid did i make that assumption + + + align:start position:0% +rigid did i make that assumption +anywhere + + align:start position:0% + + + + align:start position:0% + +i did not + + align:start position:0% +i did not + + + align:start position:0% +i did not +that means + + align:start position:0% +that means + + + align:start position:0% +that means +that eve in fact i'm assuming these are + + align:start position:0% +that eve in fact i'm assuming these are + + + align:start position:0% +that eve in fact i'm assuming these are +like independent hockey pucks with + + align:start position:0% +like independent hockey pucks with + + + align:start position:0% +like independent hockey pucks with +rockets attached to them + + align:start position:0% +rockets attached to them + + + align:start position:0% +rockets attached to them +right + + align:start position:0% + + + + align:start position:0% + +these are independent hockey pucks with + + align:start position:0% +these are independent hockey pucks with + + + align:start position:0% +these are independent hockey pucks with +rockets attached to them add up the + + align:start position:0% +rockets attached to them add up the + + + align:start position:0% +rockets attached to them add up the +forces of all the rockets + + align:start position:0% +forces of all the rockets + + + align:start position:0% +forces of all the rockets +i take the total mass i find the central + + align:start position:0% +i take the total mass i find the central + + + align:start position:0% +i take the total mass i find the central +mass and i go a physical damage + + align:start position:0% +mass and i go a physical damage + + + align:start position:0% +mass and i go a physical damage +so i made no assumption + + align:start position:0% +so i made no assumption + + + align:start position:0% +so i made no assumption +that the particles are connected now + + align:start position:0% +that the particles are connected now + + + align:start position:0% +that the particles are connected now +here's the tough question + + align:start position:0% +here's the tough question + + + align:start position:0% +here's the tough question +if the particles were rigidly connected + + align:start position:0% +if the particles were rigidly connected + + + align:start position:0% +if the particles were rigidly connected +by massless trucks + + align:start position:0% +by massless trucks + + + align:start position:0% +by massless trucks +would this formula still hold + + align:start position:0% +would this formula still hold + + + align:start position:0% +would this formula still hold +and this is actually a deep question + + align:start position:0% +and this is actually a deep question + + + align:start position:0% +and this is actually a deep question +i won't do this + + align:start position:0% +i won't do this + + + align:start position:0% +i won't do this +in detail right now you'll see the same + + align:start position:0% +in detail right now you'll see the same + + + align:start position:0% +in detail right now you'll see the same +question pop up later so i'll give you + + align:start position:0% +question pop up later so i'll give you + + + align:start position:0% +question pop up later so i'll give you +the verbal answer right now and i'll do + + align:start position:0% +the verbal answer right now and i'll do + + + align:start position:0% +the verbal answer right now and i'll do +it in more detail later so my question + + align:start position:0% +it in more detail later so my question + + + align:start position:0% +it in more detail later so my question +to you + + align:start position:0% +to you + + + align:start position:0% +to you +if the particles are rigidly connected + + align:start position:0% +if the particles are rigidly connected + + + align:start position:0% +if the particles are rigidly connected +by massless struts would the formula + + align:start position:0% +by massless struts would the formula + + + align:start position:0% +by massless struts would the formula +still hold question mark yes or no or + + align:start position:0% +still hold question mark yes or no or + + + align:start position:0% +still hold question mark yes or no or +maybe or only on tuesdays + + align:start position:0% +maybe or only on tuesdays + + + align:start position:0% +maybe or only on tuesdays +yes and why is that + + align:start position:0% + + + + align:start position:0% + +anybody yeah go ahead yep + + align:start position:0% + + + + align:start position:0% + +that's right look if it's a rigid if the + + align:start position:0% +that's right look if it's a rigid if the + + + align:start position:0% +that's right look if it's a rigid if the +particles are originally connected + + align:start position:0% +particles are originally connected + + + align:start position:0% +particles are originally connected +there might be internal forces for sure + + align:start position:0% +there might be internal forces for sure + + + align:start position:0% +there might be internal forces for sure +in fact there will be internal forces + + align:start position:0% +in fact there will be internal forces + + + align:start position:0% +in fact there will be internal forces +right + + align:start position:0% +right + + + align:start position:0% +right +but + + align:start position:0% +but + + + align:start position:0% +but +you know what you give to one particle + + align:start position:0% +you know what you give to one particle + + + align:start position:0% +you know what you give to one particle +you're going to add to the other + + align:start position:0% +you're going to add to the other + + + align:start position:0% +you're going to add to the other +particle get it + + align:start position:0% +particle get it + + + align:start position:0% +particle get it +remember how here it kept showing you + + align:start position:0% +remember how here it kept showing you + + + align:start position:0% +remember how here it kept showing you +know this to this these internal forces + + align:start position:0% +know this to this these internal forces + + + align:start position:0% +know this to this these internal forces +when you add them keep canceling out + + align:start position:0% +when you add them keep canceling out + + + align:start position:0% +when you add them keep canceling out +these two cancelled out + + align:start position:0% +these two cancelled out + + + align:start position:0% +these two cancelled out +so even if it's rigid that holds but the + + align:start position:0% +so even if it's rigid that holds but the + + + align:start position:0% +so even if it's rigid that holds but the +beauty is it also holds if the particles + + align:start position:0% +beauty is it also holds if the particles + + + align:start position:0% +beauty is it also holds if the particles +are unconnected + + align:start position:0% +are unconnected + + + align:start position:0% +are unconnected +so it + + align:start position:0% +so it + + + align:start position:0% +so it +applies to multiple unconnected + + align:start position:0% +applies to multiple unconnected + + + align:start position:0% +applies to multiple unconnected +particles + + align:start position:0% +particles + + + align:start position:0% +particles +and it applies to a rigid body is + + align:start position:0% +and it applies to a rigid body is + + + align:start position:0% +and it applies to a rigid body is +everyone good with this + + align:start position:0% +everyone good with this + + + align:start position:0% +everyone good with this +i'm not going to show you the internal + + align:start position:0% +i'm not going to show you the internal + + + align:start position:0% +i'm not going to show you the internal +forces canceling out it's pretty obvious + + align:start position:0% +forces canceling out it's pretty obvious + + + align:start position:0% +forces canceling out it's pretty obvious +because you've kind of seen it here + + align:start position:0% +because you've kind of seen it here + + + align:start position:0% +because you've kind of seen it here +good + + align:start position:0% +good + + + align:start position:0% +good +so we have just derived + + align:start position:0% +so we have just derived + + + align:start position:0% +so we have just derived +this guy + + align:start position:0% + + + + align:start position:0% + +done + + align:start position:0% +done + + + align:start position:0% +done +now i'm going to derive this guy + + align:start position:0% +now i'm going to derive this guy + + + align:start position:0% +now i'm going to derive this guy +and then i will reduce it to this + + align:start position:0% +and then i will reduce it to this + + + align:start position:0% +and then i will reduce it to this +that's the roadmap for the remaining 35 + + align:start position:0% +that's the roadmap for the remaining 35 + + + align:start position:0% +that's the roadmap for the remaining 35 +minutes okay + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +i'm going to keep referring to that + + align:start position:0% +i'm going to keep referring to that + + + align:start position:0% +i'm going to keep referring to that +diagram all right that picture there + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so now now how did i do this + + align:start position:0% +so now now how did i do this + + + align:start position:0% +so now now how did i do this +i just took a summation of the f + + align:start position:0% +i just took a summation of the f + + + align:start position:0% +i just took a summation of the f +physical m equation right + + align:start position:0% +physical m equation right + + + align:start position:0% +physical m equation right +i'm going to do the same thing + + align:start position:0% +i'm going to do the same thing + + + align:start position:0% +i'm going to do the same thing +with that with that tau is tau + + align:start position:0% +with that with that tau is tau + + + align:start position:0% +with that with that tau is tau +is equal to d by d a dt of h plus + + align:start position:0% +is equal to d by d a dt of h plus + + + align:start position:0% +is equal to d by d a dt of h plus +v cross b i'm going to just sum it + + align:start position:0% +v cross b i'm going to just sum it + + + align:start position:0% +v cross b i'm going to just sum it +no great magic right + + align:start position:0% +no great magic right + + + align:start position:0% +no great magic right +and i'm going to add it up and show that + + align:start position:0% +and i'm going to add it up and show that + + + align:start position:0% +and i'm going to add it up and show that +you get the same equation + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +you know the reason we do derivations + + align:start position:0% +you know the reason we do derivations + + + align:start position:0% +you know the reason we do derivations +which are really boring + + align:start position:0% +which are really boring + + + align:start position:0% +which are really boring +no i said the wrong the reason that even + + align:start position:0% +no i said the wrong the reason that even + + + align:start position:0% +no i said the wrong the reason that even +though derivations could be boring we do + + align:start position:0% +though derivations could be boring we do + + + align:start position:0% +though derivations could be boring we do +them + + align:start position:0% +them + + + align:start position:0% +them +is because when you take something like + + align:start position:0% +is because when you take something like + + + align:start position:0% +is because when you take something like +this makes a lot of sense great and i do + + align:start position:0% +this makes a lot of sense great and i do + + + align:start position:0% +this makes a lot of sense great and i do +like to do this but when you generalize + + align:start position:0% +like to do this but when you generalize + + + align:start position:0% +like to do this but when you generalize +them they generalize kinda but they're + + align:start position:0% +them they generalize kinda but they're + + + align:start position:0% +them they generalize kinda but they're +pitfalls + + align:start position:0% +pitfalls + + + align:start position:0% +pitfalls +and the reason to be precise + + align:start position:0% +and the reason to be precise + + + align:start position:0% +and the reason to be precise +is because it's those pitfalls + + align:start position:0% +is because it's those pitfalls + + + align:start position:0% +is because it's those pitfalls +that you need to be aware of + + align:start position:0% +that you need to be aware of + + + align:start position:0% +that you need to be aware of +right + + align:start position:0% +right + + + align:start position:0% +right +so when you're a supervisor at nasa + + align:start position:0% +so when you're a supervisor at nasa + + + align:start position:0% +so when you're a supervisor at nasa +right you're the person who's going to + + align:start position:0% +right you're the person who's going to + + + align:start position:0% +right you're the person who's going to +catch the + + align:start position:0% +catch the + + + align:start position:0% +catch the +you know dude you missed a term you know + + align:start position:0% +you know dude you missed a term you know + + + align:start position:0% +you know dude you missed a term you know +you know you're the you're the that's + + align:start position:0% +you know you're the you're the that's + + + align:start position:0% +you know you're the you're the that's +your thing right you're the dude you mr + + align:start position:0% +your thing right you're the dude you mr + + + align:start position:0% +your thing right you're the dude you mr +term people right so + + align:start position:0% + + + + align:start position:0% + +that was a terrible movie by the dude + + align:start position:0% +that was a terrible movie by the dude + + + align:start position:0% +that was a terrible movie by the dude +where's my car + + align:start position:0% +where's my car + + + align:start position:0% +where's my car +terrible movie + + align:start position:0% +terrible movie + + + align:start position:0% +terrible movie +i finally saw it + + align:start position:0% + + + + align:start position:0% + +you know i was trying to be cool i + + align:start position:0% +you know i was trying to be cool i + + + align:start position:0% +you know i was trying to be cool i +thought yeah i'll see it you know it's + + align:start position:0% +thought yeah i'll see it you know it's + + + align:start position:0% +thought yeah i'll see it you know it's +terrible i'm sorry if you guys liked it + + align:start position:0% +terrible i'm sorry if you guys liked it + + + align:start position:0% +terrible i'm sorry if you guys liked it +i'm not cool okay + + align:start position:0% +i'm not cool okay + + + align:start position:0% +i'm not cool okay +did anyone like it + + align:start position:0% +did anyone like it + + + align:start position:0% +did anyone like it +come on + + align:start position:0% + + + + align:start position:0% + +and i had to detox i haven't watched a + + align:start position:0% +and i had to detox i haven't watched a + + + align:start position:0% +and i had to detox i haven't watched a +monty python i was like that's better + + align:start position:0% +monty python i was like that's better + + + align:start position:0% +monty python i was like that's better +okay + + align:start position:0% +okay + + + align:start position:0% +okay +i just i know i aged my i just dated + + align:start position:0% +i just i know i aged my i just dated + + + align:start position:0% +i just i know i aged my i just dated +myself but + + align:start position:0% + + + + align:start position:0% + +okay so we know + + align:start position:0% +okay so we know + + + align:start position:0% +okay so we know +that our oh you know i'm just rewriting + + align:start position:0% +that our oh you know i'm just rewriting + + + align:start position:0% +that our oh you know i'm just rewriting +that guy now + + align:start position:0% +that guy now + + + align:start position:0% +that guy now +right the torque + + align:start position:0% +right the torque + + + align:start position:0% +right the torque +i'm actually just writing defining + + align:start position:0% +i'm actually just writing defining + + + align:start position:0% +i'm actually just writing defining +torque + + align:start position:0% +torque + + + align:start position:0% +torque +is equal to + + align:start position:0% + + + + align:start position:0% + +this is the definition of torque right + + align:start position:0% +this is the definition of torque right + + + align:start position:0% +this is the definition of torque right +that's the total torque on particle i + + align:start position:0% +that's the total torque on particle i + + + align:start position:0% +that's the total torque on particle i +from the external force + + align:start position:0% +from the external force + + + align:start position:0% +from the external force +okay + + align:start position:0% +okay + + + align:start position:0% +okay +now what if there's an internal force + + align:start position:0% +now what if there's an internal force + + + align:start position:0% +now what if there's an internal force +what if there's an internal force + + align:start position:0% +what if there's an internal force + + + align:start position:0% +what if there's an internal force +from particle j onto particle i + + align:start position:0% + + + + align:start position:0% + +right what if there's a force like that + + align:start position:0% + + + + align:start position:0% + +right if you look at particle i it'll + + align:start position:0% +right if you look at particle i it'll + + + align:start position:0% +right if you look at particle i it'll +have two forces let's write it down + + align:start position:0% +have two forces let's write it down + + + align:start position:0% +have two forces let's write it down +remember i said here i just hand waved + + align:start position:0% +remember i said here i just hand waved + + + align:start position:0% +remember i said here i just hand waved +it in this case let's write it down what + + align:start position:0% +it in this case let's write it down what + + + align:start position:0% +it in this case let's write it down what +happens + + align:start position:0% +happens + + + align:start position:0% +happens +you will get another torque which is + + align:start position:0% + + + + align:start position:0% + +and i'm going to write it like this + + align:start position:0% +and i'm going to write it like this + + + align:start position:0% +and i'm going to write it like this +force on particle i + + align:start position:0% +force on particle i + + + align:start position:0% +force on particle i +from particle j + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and i'll get you know k i mean i'll get + + align:start position:0% +and i'll get you know k i mean i'll get + + + align:start position:0% +and i'll get you know k i mean i'll get +a bunch of these terms + + align:start position:0% +a bunch of these terms + + + align:start position:0% +a bunch of these terms +right from every other particle that + + align:start position:0% +right from every other particle that + + + align:start position:0% +right from every other particle that +wants to you know push in internally in + + align:start position:0% +wants to you know push in internally in + + + align:start position:0% +wants to you know push in internally in +an internal force on this particle + + align:start position:0% +an internal force on this particle + + + align:start position:0% +an internal force on this particle +right so that's the force total force on + + align:start position:0% +right so that's the force total force on + + + align:start position:0% +right so that's the force total force on +this particle + + align:start position:0% +this particle + + + align:start position:0% +this particle +now + + align:start position:0% +now + + + align:start position:0% +now +if you look at particle j + + align:start position:0% + + + + align:start position:0% + +right + + align:start position:0% +right + + + align:start position:0% +right +because it's a counter i need to look at + + align:start position:0% +because it's a counter i need to look at + + + align:start position:0% +because it's a counter i need to look at +each particle + + align:start position:0% +each particle + + + align:start position:0% +each particle +i'm going to get + + align:start position:0% +i'm going to get + + + align:start position:0% +i'm going to get +r the torque on it is r o j + + align:start position:0% +r the torque on it is r o j + + + align:start position:0% +r the torque on it is r o j +cross + + align:start position:0% +cross + + + align:start position:0% +cross +f + + align:start position:0% +f + + + align:start position:0% +f +j + + align:start position:0% +j + + + align:start position:0% +j +plus + + align:start position:0% +plus + + + align:start position:0% +plus +r + + align:start position:0% +r + + + align:start position:0% +r +oj + + align:start position:0% +oj + + + align:start position:0% +oj +cross + + align:start position:0% +cross + + + align:start position:0% +cross +f what am i going to get here what's the + + align:start position:0% +f what am i going to get here what's the + + + align:start position:0% +f what am i going to get here what's the +equivalent here + + align:start position:0% + + + + align:start position:0% + +dot dot + + align:start position:0% +dot dot + + + align:start position:0% +dot dot +right + + align:start position:0% +right + + + align:start position:0% +right +now if i add them up + + align:start position:0% + + + + align:start position:0% + +what do i get here some of all the + + align:start position:0% +what do i get here some of all the + + + align:start position:0% +what do i get here some of all the +torques + + align:start position:0% + + + + align:start position:0% + +right by the way why does this cancel + + align:start position:0% +right by the way why does this cancel + + + align:start position:0% +right by the way why does this cancel +out + + align:start position:0% +out + + + align:start position:0% +out +oh sorry sir so sorry we'll come back so + + align:start position:0% +oh sorry sir so sorry we'll come back so + + + align:start position:0% +oh sorry sir so sorry we'll come back so +add them up what do i get here + + align:start position:0% +add them up what do i get here + + + align:start position:0% +add them up what do i get here +you said it right + + align:start position:0% +you said it right + + + align:start position:0% +you said it right +huh talking the entire thing and the + + align:start position:0% +huh talking the entire thing and the + + + align:start position:0% +huh talking the entire thing and the +word the way i'm defining that is + + align:start position:0% +word the way i'm defining that is + + + align:start position:0% +word the way i'm defining that is +t + + align:start position:0% +t + + + align:start position:0% +t +capital t + + align:start position:0% +capital t + + + align:start position:0% +capital t +it's the sum of the torques on the + + align:start position:0% +it's the sum of the torques on the + + + align:start position:0% +it's the sum of the torques on the +individual particles added up about + + align:start position:0% +individual particles added up about + + + align:start position:0% +individual particles added up about +reference point q + + align:start position:0% +reference point q + + + align:start position:0% +reference point q +all right + + align:start position:0% +all right + + + align:start position:0% +all right +excuse me + + align:start position:0% + + + + align:start position:0% + +torque + + align:start position:0% +torque + + + align:start position:0% +torque +on the ensemble about point q + + align:start position:0% +on the ensemble about point q + + + align:start position:0% +on the ensemble about point q +and i define it as + + align:start position:0% +and i define it as + + + align:start position:0% +and i define it as +sigma + + align:start position:0% +sigma + + + align:start position:0% +sigma +i is equal to 1 + + align:start position:0% +i is equal to 1 + + + align:start position:0% +i is equal to 1 +to n if the ensemble has n points + + align:start position:0% +to n if the ensemble has n points + + + align:start position:0% +to n if the ensemble has n points +r + + align:start position:0% +r + + + align:start position:0% +r +o i + + align:start position:0% +o i + + + align:start position:0% +o i +cross + + align:start position:0% +cross + + + align:start position:0% +cross +f + + align:start position:0% +f + + + align:start position:0% +f +i + + align:start position:0% +i + + + align:start position:0% +i +and here's the deal + + align:start position:0% +and here's the deal + + + align:start position:0% +and here's the deal +what is f i j what's the relationship + + align:start position:0% +what is f i j what's the relationship + + + align:start position:0% +what is f i j what's the relationship +between fij and fji + + align:start position:0% +between fij and fji + + + align:start position:0% +between fij and fji +so all these terms cancel out + + align:start position:0% +so all these terms cancel out + + + align:start position:0% +so all these terms cancel out +all the internal terms cancel out get it + + align:start position:0% +all the internal terms cancel out get it + + + align:start position:0% +all the internal terms cancel out get it +i mean look here's the deal + + align:start position:0% +i mean look here's the deal + + + align:start position:0% +i mean look here's the deal +if you take + + align:start position:0% +if you take + + + align:start position:0% +if you take +two particles + + align:start position:0% + + + + align:start position:0% + +let's say let's say you're flying a + + align:start position:0% +let's say let's say you're flying a + + + align:start position:0% +let's say let's say you're flying a +plane right let's say launcher or you + + align:start position:0% +plane right let's say launcher or you + + + align:start position:0% +plane right let's say launcher or you +know yeah there's a you're flying a + + align:start position:0% +know yeah there's a you're flying a + + + align:start position:0% +know yeah there's a you're flying a +plane right + + align:start position:0% +plane right + + + align:start position:0% +plane right +now if two kids sitting next to each + + align:start position:0% +now if two kids sitting next to each + + + align:start position:0% +now if two kids sitting next to each +other pushing each other does it make + + align:start position:0% +other pushing each other does it make + + + align:start position:0% +other pushing each other does it make +any difference to the flight of the + + align:start position:0% +any difference to the flight of the + + + align:start position:0% +any difference to the flight of the +plane + + align:start position:0% + + + + align:start position:0% + +it doesn't as long as they're stably you + + align:start position:0% +it doesn't as long as they're stably you + + + align:start position:0% +it doesn't as long as they're stably you +know they're just kind of pushing each + + align:start position:0% +know they're just kind of pushing each + + + align:start position:0% +know they're just kind of pushing each +other in the stable against their chairs + + align:start position:0% +other in the stable against their chairs + + + align:start position:0% +other in the stable against their chairs +their seats it makes no difference to + + align:start position:0% +their seats it makes no difference to + + + align:start position:0% +their seats it makes no difference to +the flight of the plane right it's an + + align:start position:0% +the flight of the plane right it's an + + + align:start position:0% +the flight of the plane right it's an +internal matter + + align:start position:0% +internal matter + + + align:start position:0% +internal matter +and neutron sitting outside doesn't see + + align:start position:0% +and neutron sitting outside doesn't see + + + align:start position:0% +and neutron sitting outside doesn't see +this + + align:start position:0% +this + + + align:start position:0% +this +you understand + + align:start position:0% +you understand + + + align:start position:0% +you understand +so that's the way to think about the + + align:start position:0% +so that's the way to think about the + + + align:start position:0% +so that's the way to think about the +internal forces make no difference they + + align:start position:0% +internal forces make no difference they + + + align:start position:0% +internal forces make no difference they +cancel out they only make a difference + + align:start position:0% +cancel out they only make a difference + + + align:start position:0% +cancel out they only make a difference +by the way + + align:start position:0% +by the way + + + align:start position:0% +by the way +if the kids are moving around + + align:start position:0% +if the kids are moving around + + + align:start position:0% +if the kids are moving around +but if it's static + + align:start position:0% +but if it's static + + + align:start position:0% +but if it's static +which is what happens in a rigid body + + align:start position:0% +which is what happens in a rigid body + + + align:start position:0% +which is what happens in a rigid body +they make no difference + + align:start position:0% +they make no difference + + + align:start position:0% +they make no difference +okay yep + + align:start position:0% + + + + align:start position:0% + +how's that that was quick huh + + align:start position:0% +how's that that was quick huh + + + align:start position:0% +how's that that was quick huh +sorry i'm sure written q thank you + + align:start position:0% + + + + align:start position:0% + +okay so that's the definition of the + + align:start position:0% +okay so that's the definition of the + + + align:start position:0% +okay so that's the definition of the +total torque on a rigid body + + align:start position:0% +total torque on a rigid body + + + align:start position:0% +total torque on a rigid body +i write it as capital t and it's simply + + align:start position:0% +i write it as capital t and it's simply + + + align:start position:0% +i write it as capital t and it's simply +the sum of all this and i can ignore the + + align:start position:0% +the sum of all this and i can ignore the + + + align:start position:0% +the sum of all this and i can ignore the +internal forces got it + + align:start position:0% + + + + align:start position:0% + +okay so that's the first result i want + + align:start position:0% +okay so that's the first result i want + + + align:start position:0% +okay so that's the first result i want +to show you in that's in in my trying to + + align:start position:0% +to show you in that's in in my trying to + + + align:start position:0% +to show you in that's in in my trying to +prove that other equation + + align:start position:0% +prove that other equation + + + align:start position:0% +prove that other equation +now let's do the same for + + align:start position:0% +now let's do the same for + + + align:start position:0% +now let's do the same for +angular momentum because the three terms + + align:start position:0% +angular momentum because the three terms + + + align:start position:0% +angular momentum because the three terms +i'm going to sum up the torques i'm + + align:start position:0% +i'm going to sum up the torques i'm + + + align:start position:0% +i'm going to sum up the torques i'm +going to solve the angular momentum and + + align:start position:0% +going to solve the angular momentum and + + + align:start position:0% +going to solve the angular momentum and +i'm going to try and sum up this term + + align:start position:0% +i'm going to try and sum up this term + + + align:start position:0% +i'm going to try and sum up this term +okay yep + + align:start position:0% +okay yep + + + align:start position:0% +okay yep +yeah so i understand like right yeah + + align:start position:0% +yeah so i understand like right yeah + + + align:start position:0% +yeah so i understand like right yeah +yeah + + align:start position:0% +yeah + + + align:start position:0% +yeah +but if you know because + + align:start position:0% + + + + align:start position:0% + +yeah so it turns out that that's a quick + + align:start position:0% +yeah so it turns out that that's a quick + + + align:start position:0% +yeah so it turns out that that's a quick +question it's a very deep question it + + align:start position:0% +question it's a very deep question it + + + align:start position:0% +question it's a very deep question it +turns out that even in that case it + + align:start position:0% +turns out that even in that case it + + + align:start position:0% +turns out that even in that case it +becomes goes to zero + + align:start position:0% +becomes goes to zero + + + align:start position:0% +becomes goes to zero +right i won't write it out here but let + + align:start position:0% +right i won't write it out here but let + + + align:start position:0% +right i won't write it out here but let +me explain why first of all if it's a + + align:start position:0% +me explain why first of all if it's a + + + align:start position:0% +me explain why first of all if it's a +continuum + + align:start position:0% +continuum + + + align:start position:0% +continuum +then these two are very close + + align:start position:0% +then these two are very close + + + align:start position:0% +then these two are very close +right so the terms go to zero if they're + + align:start position:0% +right so the terms go to zero if they're + + + align:start position:0% +right so the terms go to zero if they're +you know attached by massless rods then + + align:start position:0% +you know attached by massless rods then + + + align:start position:0% +you know attached by massless rods then +you've got to use that kind of an + + align:start position:0% +you've got to use that kind of an + + + align:start position:0% +you've got to use that kind of an +argument + + align:start position:0% +argument + + + align:start position:0% +argument +and you can show that fij is the + + align:start position:0% +and you can show that fij is the + + + align:start position:0% +and you can show that fij is the +negative of fji + + align:start position:0% +negative of fji + + + align:start position:0% +negative of fji +and you can you know you can expand it + + align:start position:0% +and you can you know you can expand it + + + align:start position:0% +and you can you know you can expand it +all out and write f r i j and kind of + + align:start position:0% +all out and write f r i j and kind of + + + align:start position:0% +all out and write f r i j and kind of +write it out like that you're sure the + + align:start position:0% +write it out like that you're sure the + + + align:start position:0% +write it out like that you're sure the +term still vanishes + + align:start position:0% +term still vanishes + + + align:start position:0% +term still vanishes +okay and if you would like + + align:start position:0% +okay and if you would like + + + align:start position:0% +okay and if you would like +if you're interested in that if you come + + align:start position:0% +if you're interested in that if you come + + + align:start position:0% +if you're interested in that if you come +to uh if you come and see me i can show + + align:start position:0% +to uh if you come and see me i can show + + + align:start position:0% +to uh if you come and see me i can show +you some of the stuff + + align:start position:0% +you some of the stuff + + + align:start position:0% +you some of the stuff +all right so this term these so that + + align:start position:0% +all right so this term these so that + + + align:start position:0% +all right so this term these so that +that sort of body you're talking about + + align:start position:0% +that sort of body you're talking about + + + align:start position:0% +that sort of body you're talking about +which is not a real body a real body is + + align:start position:0% +which is not a real body a real body is + + + align:start position:0% +which is not a real body a real body is +all particles right next to each other + + align:start position:0% +all particles right next to each other + + + align:start position:0% +all particles right next to each other +right even in that sort of a thing these + + align:start position:0% +right even in that sort of a thing these + + + align:start position:0% +right even in that sort of a thing these +terms will cancel out it's very cool + + align:start position:0% +terms will cancel out it's very cool + + + align:start position:0% +terms will cancel out it's very cool +actually + + align:start position:0% +actually + + + align:start position:0% +actually +and in fact aj and i spent banged our + + align:start position:0% +and in fact aj and i spent banged our + + + align:start position:0% +and in fact aj and i spent banged our +heads heads against this + + align:start position:0% +heads heads against this + + + align:start position:0% +heads heads against this +every year we're like ah why does it + + align:start position:0% +every year we're like ah why does it + + + align:start position:0% +every year we're like ah why does it +cancel again and oh yeah finally cancels + + align:start position:0% +cancel again and oh yeah finally cancels + + + align:start position:0% +cancel again and oh yeah finally cancels +okay + + align:start position:0% +okay + + + align:start position:0% +okay +all right + + align:start position:0% +all right + + + align:start position:0% +all right +that's a good question it's actually not + + align:start position:0% +that's a good question it's actually not + + + align:start position:0% +that's a good question it's actually not +that obvious + + align:start position:0% +that obvious + + + align:start position:0% +that obvious +you know einstein was giving a speech + + align:start position:0% +you know einstein was giving a speech + + + align:start position:0% +you know einstein was giving a speech +i've forgotten where i think it is in + + align:start position:0% +i've forgotten where i think it is in + + + align:start position:0% +i've forgotten where i think it is in +berlin + + align:start position:0% +berlin + + + align:start position:0% +berlin +in the 50s and uh + + align:start position:0% +in the 50s and uh + + + align:start position:0% +in the 50s and uh +he wrote something you know i'm einstein + + align:start position:0% +he wrote something you know i'm einstein + + + align:start position:0% +he wrote something you know i'm einstein +you know so it's a reasonable comparison + + align:start position:0% +you know so it's a reasonable comparison + + + align:start position:0% +you know so it's a reasonable comparison +anyway so he wrote something or an + + align:start position:0% +anyway so he wrote something or an + + + align:start position:0% +anyway so he wrote something or an +equation + + align:start position:0% +equation + + + align:start position:0% +equation +and he said obviously and he wrote the + + align:start position:0% +and he said obviously and he wrote the + + + align:start position:0% +and he said obviously and he wrote the +next i think the next result was easily + + align:start position:0% +next i think the next result was easily + + + align:start position:0% +next i think the next result was easily +mc square or something very profound + + align:start position:0% +mc square or something very profound + + + align:start position:0% +mc square or something very profound +obviously right and a young physicist on + + align:start position:0% +obviously right and a young physicist on + + + align:start position:0% +obviously right and a young physicist on +the back apparently said professor + + align:start position:0% +the back apparently said professor + + + align:start position:0% +the back apparently said professor +einstein it's not so obvious to me + + align:start position:0% +einstein it's not so obvious to me + + + align:start position:0% +einstein it's not so obvious to me +and all the you know the old bearded you + + align:start position:0% +and all the you know the old bearded you + + + align:start position:0% +and all the you know the old bearded you +know professors kind of turn up at him + + align:start position:0% +know professors kind of turn up at him + + + align:start position:0% +know professors kind of turn up at him +and stare at him right + + align:start position:0% +and stare at him right + + + align:start position:0% +and stare at him right +and the guy's like oh sorry can he sit + + align:start position:0% +and the guy's like oh sorry can he sit + + + align:start position:0% +and the guy's like oh sorry can he sit +down and then einstein goes you know + + align:start position:0% +down and then einstein goes you know + + + align:start position:0% +down and then einstein goes you know +actually you're exactly right and he + + align:start position:0% +actually you're exactly right and he + + + align:start position:0% +actually you're exactly right and he +takes another four blackboards to derive + + align:start position:0% +takes another four blackboards to derive + + + align:start position:0% +takes another four blackboards to derive +that and if i remember correctly the + + align:start position:0% +that and if i remember correctly the + + + align:start position:0% +that and if i remember correctly the +story is that that man + + align:start position:0% +story is that that man + + + align:start position:0% +story is that that man +that kid was leola landau who then won a + + align:start position:0% +that kid was leola landau who then won a + + + align:start position:0% +that kid was leola landau who then won a +nobel prize himself so you might win a + + align:start position:0% +nobel prize himself so you might win a + + + align:start position:0% +nobel prize himself so you might win a +nobel prize like me + + align:start position:0% +nobel prize like me + + + align:start position:0% +nobel prize like me +all right + + align:start position:0% +all right + + + align:start position:0% +all right +okay so + + align:start position:0% +okay so + + + align:start position:0% +okay so +this is the uh so let's do the next term + + align:start position:0% +this is the uh so let's do the next term + + + align:start position:0% +this is the uh so let's do the next term +which is a + + align:start position:0% +which is a + + + align:start position:0% +which is a +h + + align:start position:0% +h + + + align:start position:0% +h +i q + + align:start position:0% + + + + align:start position:0% + +is equal to + + align:start position:0% +is equal to + + + align:start position:0% +is equal to +r + + align:start position:0% +r + + + align:start position:0% +r +q i + + align:start position:0% + + + + align:start position:0% + +cross + + align:start position:0% +cross + + + align:start position:0% +cross +a + + align:start position:0% +a + + + align:start position:0% +a +p i + + align:start position:0% +p i + + + align:start position:0% +p i +and if you write that out + + align:start position:0% +and if you write that out + + + align:start position:0% +and if you write that out +and you sum it up for all the particles + + align:start position:0% +and you sum it up for all the particles + + + align:start position:0% +and you sum it up for all the particles +i'm not going to do it there's no terms + + align:start position:0% +i'm not going to do it there's no terms + + + align:start position:0% +i'm not going to do it there's no terms +to cancel + + align:start position:0% +to cancel + + + align:start position:0% +to cancel +it comes out that the total angular + + align:start position:0% +it comes out that the total angular + + + align:start position:0% +it comes out that the total angular +momentum + + align:start position:0% +momentum + + + align:start position:0% +momentum +of the ensemble about point q you can + + align:start position:0% +of the ensemble about point q you can + + + align:start position:0% +of the ensemble about point q you can +define it simply as + + align:start position:0% +define it simply as + + + align:start position:0% +define it simply as +this summation + + align:start position:0% +this summation + + + align:start position:0% +this summation +which is sigma + + align:start position:0% +which is sigma + + + align:start position:0% +which is sigma +i is equal to 1 + + align:start position:0% +i is equal to 1 + + + align:start position:0% +i is equal to 1 +to n where n is the number of particles + + align:start position:0% +to n where n is the number of particles + + + align:start position:0% +to n where n is the number of particles +in the ensemble + + align:start position:0% +in the ensemble + + + align:start position:0% +in the ensemble +r + + align:start position:0% +r + + + align:start position:0% +r +q i + + align:start position:0% +q i + + + align:start position:0% +q i +cross a + + align:start position:0% +cross a + + + align:start position:0% +cross a +p + + align:start position:0% +p + + + align:start position:0% +p +i + + align:start position:0% + + + + align:start position:0% + +hm + + align:start position:0% +hm + + + align:start position:0% +hm +did i miss something + + align:start position:0% +did i miss something + + + align:start position:0% +did i miss something +eq + + align:start position:0% + + + + align:start position:0% + +did i miss something is right + + align:start position:0% +did i miss something is right + + + align:start position:0% +did i miss something is right +yeah okay + + align:start position:0% + + + + align:start position:0% + +okay and then finally + + align:start position:0% +okay and then finally + + + align:start position:0% +okay and then finally +let's plug this + + align:start position:0% +let's plug this + + + align:start position:0% +let's plug this +and this + + align:start position:0% +and this + + + align:start position:0% +and this +into that equation + + align:start position:0% +into that equation + + + align:start position:0% +into that equation +and into actually that equation + + align:start position:0% +and into actually that equation + + + align:start position:0% +and into actually that equation +so now we can say tau i + + align:start position:0% + + + + align:start position:0% + +point q + + align:start position:0% +point q + + + align:start position:0% +point q +is equal to i'm just recreating that + + align:start position:0% +is equal to i'm just recreating that + + + align:start position:0% +is equal to i'm just recreating that +equation i'm going to add it all up now + + align:start position:0% +equation i'm going to add it all up now + + + align:start position:0% +equation i'm going to add it all up now +that we've done the hard work + + align:start position:0% +that we've done the hard work + + + align:start position:0% +that we've done the hard work +a + + align:start position:0% +a + + + align:start position:0% +a +d by dt + + align:start position:0% +d by dt + + + align:start position:0% +d by dt +of + + align:start position:0% +of + + + align:start position:0% +of +a + + align:start position:0% +a + + + align:start position:0% +a +h + + align:start position:0% +h + + + align:start position:0% +h +by q + + align:start position:0% +by q + + + align:start position:0% +by q +i'm just rewriting that plus + + align:start position:0% +i'm just rewriting that plus + + + align:start position:0% +i'm just rewriting that plus +a + + align:start position:0% +a + + + align:start position:0% +a +v q + + align:start position:0% +v q + + + align:start position:0% +v q +cross + + align:start position:0% +cross + + + align:start position:0% +cross +a + + align:start position:0% +a + + + align:start position:0% +a +p + + align:start position:0% +p + + + align:start position:0% +p +i + + align:start position:0% +i + + + align:start position:0% +i +repeat + + align:start position:0% +repeat + + + align:start position:0% +repeat +n times + + align:start position:0% +n times + + + align:start position:0% +n times +when you add it up + + align:start position:0% +when you add it up + + + align:start position:0% +when you add it up +we can see that + + align:start position:0% +we can see that + + + align:start position:0% +we can see that +this + + align:start position:0% +this + + + align:start position:0% +this +if you add this up use this to get + + align:start position:0% +if you add this up use this to get + + + align:start position:0% +if you add this up use this to get +the total torque on the ensemble + + align:start position:0% + + + + align:start position:0% + +right + + align:start position:0% +right + + + align:start position:0% +right +that's it by definition right + + align:start position:0% + + + + align:start position:0% + +is equal to what is the summations of + + align:start position:0% +is equal to what is the summations of + + + align:start position:0% +is equal to what is the summations of +this + + align:start position:0% +this + + + align:start position:0% +this +anyone + + align:start position:0% +anyone + + + align:start position:0% +anyone +sorry + + align:start position:0% + + + + align:start position:0% + +yeah it's just + + align:start position:0% +yeah it's just + + + align:start position:0% +yeah it's just +a + + align:start position:0% +a + + + align:start position:0% +a +d by dt + + align:start position:0% +d by dt + + + align:start position:0% +d by dt +a + + align:start position:0% +a + + + align:start position:0% +a +h + + align:start position:0% +h + + + align:start position:0% +h +i how about q + + align:start position:0% + + + + align:start position:0% + +say it again + + align:start position:0% + + + + align:start position:0% + +yeah if it's capital here + + align:start position:0% +yeah if it's capital here + + + align:start position:0% +yeah if it's capital here +if it's yeah this is yeah that's right + + align:start position:0% +if it's yeah this is yeah that's right + + + align:start position:0% +if it's yeah this is yeah that's right +and what's that going to + + align:start position:0% +and what's that going to + + + align:start position:0% +and what's that going to +become + + align:start position:0% + + + + align:start position:0% + +anyone + + align:start position:0% + + + + align:start position:0% + +it's just going to be look it's just + + align:start position:0% +it's just going to be look it's just + + + align:start position:0% +it's just going to be look it's just +good this is constant right and the + + align:start position:0% +good this is constant right and the + + + align:start position:0% +good this is constant right and the +summing this hang up add up all the + + align:start position:0% +summing this hang up add up all the + + + align:start position:0% +summing this hang up add up all the +linear momentum of the individual + + align:start position:0% +linear momentum of the individual + + + align:start position:0% +linear momentum of the individual +particles + + align:start position:0% +particles + + + align:start position:0% +particles +to get the linear momentum of the total + + align:start position:0% +to get the linear momentum of the total + + + align:start position:0% +to get the linear momentum of the total +ensemble + + align:start position:0% +ensemble + + + align:start position:0% +ensemble +so that's going to be + + align:start position:0% + + + + align:start position:0% + +capital p because it's an ensemble + + align:start position:0% + + + + align:start position:0% + +and that + + align:start position:0% +and that + + + align:start position:0% +and that +is that equation + + align:start position:0% +is that equation + + + align:start position:0% +is that equation +got it + + align:start position:0% +got it + + + align:start position:0% +got it +the sum sum sum it's done + + align:start position:0% + + + + align:start position:0% + +any questions + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +by the way the same things apply right + + align:start position:0% +by the way the same things apply right + + + align:start position:0% +by the way the same things apply right +so torque is equal to rate of change of + + align:start position:0% +so torque is equal to rate of change of + + + align:start position:0% +so torque is equal to rate of change of +angular momentum of the ensemble what + + align:start position:0% +angular momentum of the ensemble what + + + align:start position:0% +angular momentum of the ensemble what +happens if the reference point is + + align:start position:0% +happens if the reference point is + + + align:start position:0% +happens if the reference point is +stationary + + align:start position:0% +stationary + + + align:start position:0% +stationary +this term goes to zero right + + align:start position:0% +this term goes to zero right + + + align:start position:0% +this term goes to zero right +if the reference point is moving + + align:start position:0% +if the reference point is moving + + + align:start position:0% +if the reference point is moving +parallel + + align:start position:0% +parallel + + + align:start position:0% +parallel +to the center of mass + + align:start position:0% +to the center of mass + + + align:start position:0% +to the center of mass +this term goes to starts with z + + align:start position:0% +this term goes to starts with z + + + align:start position:0% +this term goes to starts with z +zero right same thing right similar + + align:start position:0% +zero right same thing right similar + + + align:start position:0% +zero right same thing right similar +concepts just added it up all right + + align:start position:0% +concepts just added it up all right + + + align:start position:0% +concepts just added it up all right +okay so now we have our second result + + align:start position:0% +okay so now we have our second result + + + align:start position:0% +okay so now we have our second result +and now + + align:start position:0% +and now + + + align:start position:0% +and now +we're going to do the final thing + + align:start position:0% +we're going to do the final thing + + + align:start position:0% +we're going to do the final thing +uh vis-a-vis the dumbbell problem we're + + align:start position:0% +uh vis-a-vis the dumbbell problem we're + + + align:start position:0% +uh vis-a-vis the dumbbell problem we're +going to show that under certain + + align:start position:0% +going to show that under certain + + + align:start position:0% +going to show that under certain +circumstances this reduces to i alpha + + align:start position:0% +circumstances this reduces to i alpha + + + align:start position:0% +circumstances this reduces to i alpha +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and everyone remember moment of inertia + + align:start position:0% +and everyone remember moment of inertia + + + align:start position:0% +and everyone remember moment of inertia +what's moment of inertia + + align:start position:0% + + + + align:start position:0% + +anyone + + align:start position:0% +anyone + + + align:start position:0% +anyone +definition what it means any anything + + align:start position:0% +definition what it means any anything + + + align:start position:0% +definition what it means any anything +yep + + align:start position:0% + + + + align:start position:0% + +yeah it's hard to just rotate something + + align:start position:0% +yeah it's hard to just rotate something + + + align:start position:0% +yeah it's hard to just rotate something +right + + align:start position:0% +right + + + align:start position:0% +right +and the basic insight is + + align:start position:0% +and the basic insight is + + + align:start position:0% +and the basic insight is +a mass that is twice the distance from + + align:start position:0% +a mass that is twice the distance from + + + align:start position:0% +a mass that is twice the distance from +you is four times more difficult to + + align:start position:0% +you is four times more difficult to + + + align:start position:0% +you is four times more difficult to +rotate + + align:start position:0% +rotate + + + align:start position:0% +rotate +square it weights with the square + + align:start position:0% +square it weights with the square + + + align:start position:0% +square it weights with the square +it's integral m r squared d r + + align:start position:0% +it's integral m r squared d r + + + align:start position:0% +it's integral m r squared d r +right + + align:start position:0% +right + + + align:start position:0% +right +and that's why we ended up with this mr + + align:start position:0% +and that's why we ended up with this mr + + + align:start position:0% +and that's why we ended up with this mr +squared here + + align:start position:0% +squared here + + + align:start position:0% +squared here +right if the dumbbell is half the length + + align:start position:0% +right if the dumbbell is half the length + + + align:start position:0% +right if the dumbbell is half the length +that equation doesn't change but it'll + + align:start position:0% +that equation doesn't change but it'll + + + align:start position:0% +that equation doesn't change but it'll +it'll it'll rotate four times as fast + + align:start position:0% +it'll it'll rotate four times as fast + + + align:start position:0% +it'll it'll rotate four times as fast +right so now let's do that final thing + + align:start position:0% +right so now let's do that final thing + + + align:start position:0% +right so now let's do that final thing +which is going from here to introducing + + align:start position:0% +which is going from here to introducing + + + align:start position:0% +which is going from here to introducing +the concept of moment of inertia + + align:start position:0% +the concept of moment of inertia + + + align:start position:0% +the concept of moment of inertia +okay and this is where you know here be + + align:start position:0% +okay and this is where you know here be + + + align:start position:0% +okay and this is where you know here be +dragons so you need to be careful + + align:start position:0% +dragons so you need to be careful + + + align:start position:0% +dragons so you need to be careful +because you cannot do that about any + + align:start position:0% +because you cannot do that about any + + + align:start position:0% +because you cannot do that about any +reference point so only some reference + + align:start position:0% +reference point so only some reference + + + align:start position:0% +reference point so only some reference +points are valid + + align:start position:0% +points are valid + + + align:start position:0% +points are valid +and that's the difference between you + + align:start position:0% +and that's the difference between you + + + align:start position:0% +and that's the difference between you +and a harvard student right okay because + + align:start position:0% +and a harvard student right okay because + + + align:start position:0% +and a harvard student right okay because +you know that + + align:start position:0% + + + + align:start position:0% + +so in order to go from here + + align:start position:0% +so in order to go from here + + + align:start position:0% +so in order to go from here +to i alpha + + align:start position:0% +to i alpha + + + align:start position:0% +to i alpha +what we'll do + + align:start position:0% +what we'll do + + + align:start position:0% +what we'll do +is we will express this guy + + align:start position:0% +is we will express this guy + + + align:start position:0% +is we will express this guy +we'll actually expand this guy + + align:start position:0% +we'll actually expand this guy + + + align:start position:0% +we'll actually expand this guy +so + + align:start position:0% +so + + + align:start position:0% +so +what is a + + align:start position:0% +what is a + + + align:start position:0% +what is a +h + + align:start position:0% +h + + + align:start position:0% +h +of the ensemble about point o + + align:start position:0% +of the ensemble about point o + + + align:start position:0% +of the ensemble about point o +it is equal to + + align:start position:0% +it is equal to + + + align:start position:0% +it is equal to +as we said earlier + + align:start position:0% +as we said earlier + + + align:start position:0% +as we said earlier +and there's a lot of math and just a lot + + align:start position:0% +and there's a lot of math and just a lot + + + align:start position:0% +and there's a lot of math and just a lot +of writing here so you'll have to bear + + align:start position:0% +of writing here so you'll have to bear + + + align:start position:0% +of writing here so you'll have to bear +with me + + align:start position:0% + + + + align:start position:0% + +but it's useful to pay attention all + + align:start position:0% +but it's useful to pay attention all + + + align:start position:0% +but it's useful to pay attention all +right + + align:start position:0% +right + + + align:start position:0% +right +even now after all these years i get + + align:start position:0% +even now after all these years i get + + + align:start position:0% +even now after all these years i get +myself confused and i have to go back to + + align:start position:0% +myself confused and i have to go back to + + + align:start position:0% +myself confused and i have to go back to +the derivations to kind of figure out + + align:start position:0% +the derivations to kind of figure out + + + align:start position:0% +the derivations to kind of figure out +because a lot of things go unsaid + + align:start position:0% + + + + align:start position:0% + +oh i cross what anyone + + align:start position:0% + + + + align:start position:0% + +anyone + + align:start position:0% +anyone + + + align:start position:0% +anyone +what's this + + align:start position:0% + + + + align:start position:0% + +cross + + align:start position:0% +cross + + + align:start position:0% +cross +p yeah exactly + + align:start position:0% +p yeah exactly + + + align:start position:0% +p yeah exactly +but i'm going to write it out like this + + align:start position:0% +but i'm going to write it out like this + + + align:start position:0% +but i'm going to write it out like this +i'm going to expand p + + align:start position:0% + + + + align:start position:0% + +right + + align:start position:0% +right + + + align:start position:0% +right +now here's a very important thing + + align:start position:0% +now here's a very important thing + + + align:start position:0% +now here's a very important thing +what did we do in the dumbbell + + align:start position:0% +what did we do in the dumbbell + + + align:start position:0% +what did we do in the dumbbell +we took + + align:start position:0% +we took + + + align:start position:0% +we took +if you remember correctly + + align:start position:0% +if you remember correctly + + + align:start position:0% +if you remember correctly +if you remember + + align:start position:0% +if you remember + + + align:start position:0% +if you remember +we expressed the velocities of these + + align:start position:0% +we expressed the velocities of these + + + align:start position:0% +we expressed the velocities of these +particles + + align:start position:0% +particles + + + align:start position:0% +particles +not by themselves but how + + align:start position:0% +not by themselves but how + + + align:start position:0% +not by themselves but how +in terms of + + align:start position:0% +in terms of + + + align:start position:0% +in terms of +the velocity of the center of mass with + + align:start position:0% +the velocity of the center of mass with + + + align:start position:0% +the velocity of the center of mass with +the and the lever arm omega cross r + + align:start position:0% +the and the lever arm omega cross r + + + align:start position:0% +the and the lever arm omega cross r +right + + align:start position:0% +right + + + align:start position:0% +right +right because we're trying to get the + + align:start position:0% +right because we're trying to get the + + + align:start position:0% +right because we're trying to get the +whole rotation thing into it so we're + + align:start position:0% +whole rotation thing into it so we're + + + align:start position:0% +whole rotation thing into it so we're +going to do the same thing here + + align:start position:0% + + + + align:start position:0% + +uh yes that should be q it should both + + align:start position:0% +uh yes that should be q it should both + + + align:start position:0% +uh yes that should be q it should both +be q + + align:start position:0% +be q + + + align:start position:0% +be q +we will let's thank you they should both + + align:start position:0% +we will let's thank you they should both + + + align:start position:0% +we will let's thank you they should both +be q + + align:start position:0% +be q + + + align:start position:0% +be q +okay + + align:start position:0% +okay + + + align:start position:0% +okay +is equal to + + align:start position:0% + + + + align:start position:0% + +and + + align:start position:0% +and + + + align:start position:0% +and +now the way we'll do it so how do we + + align:start position:0% +now the way we'll do it so how do we + + + align:start position:0% +now the way we'll do it so how do we +break it up into uh how do we rewrite + + align:start position:0% +break it up into uh how do we rewrite + + + align:start position:0% +break it up into uh how do we rewrite +this anyone + + align:start position:0% +this anyone + + + align:start position:0% +this anyone +just to keep you awake for a boring + + align:start position:0% +just to keep you awake for a boring + + + align:start position:0% +just to keep you awake for a boring +derivation + + align:start position:0% + + + + align:start position:0% + +as i'm writing can anyone figure this + + align:start position:0% +as i'm writing can anyone figure this + + + align:start position:0% +as i'm writing can anyone figure this +out + + align:start position:0% + + + + align:start position:0% + +how about this + + align:start position:0% + + + + align:start position:0% + +does this make sense + + align:start position:0% + + + + align:start position:0% + +so it again + + align:start position:0% + + + + align:start position:0% + +right so think about what i'm doing + + align:start position:0% +right so think about what i'm doing + + + align:start position:0% +right so think about what i'm doing +right + + align:start position:0% +right + + + align:start position:0% +right +here's the ensemble + + align:start position:0% +here's the ensemble + + + align:start position:0% +here's the ensemble +here's the dumbbell here's the center of + + align:start position:0% +here's the dumbbell here's the center of + + + align:start position:0% +here's the dumbbell here's the center of +the dumbbell + + align:start position:0% +the dumbbell + + + align:start position:0% +the dumbbell +i want to find the end point of the + + align:start position:0% +i want to find the end point of the + + + align:start position:0% +i want to find the end point of the +dumbbell + + align:start position:0% +dumbbell + + + align:start position:0% +dumbbell +velocity the end point + + align:start position:0% +velocity the end point + + + align:start position:0% +velocity the end point +so i find av center of + + align:start position:0% +so i find av center of + + + align:start position:0% +so i find av center of +vc + + align:start position:0% +vc + + + align:start position:0% +vc +plus omega + + align:start position:0% +plus omega + + + align:start position:0% +plus omega +cross + + align:start position:0% +cross + + + align:start position:0% +cross +that distance + + align:start position:0% +that distance + + + align:start position:0% +that distance +that is the magic formula + + align:start position:0% + + + + align:start position:0% + +yeah so fundamentally what i'm saying + + align:start position:0% +yeah so fundamentally what i'm saying + + + align:start position:0% +yeah so fundamentally what i'm saying +here + + align:start position:0% +here + + + align:start position:0% +here +is i'm assuming + + align:start position:0% +is i'm assuming + + + align:start position:0% +is i'm assuming +this is where i'm doing it + + align:start position:0% +this is where i'm doing it + + + align:start position:0% +this is where i'm doing it +that those particles + + align:start position:0% +that those particles + + + align:start position:0% +that those particles +are a rigid body + + align:start position:0% + + + + align:start position:0% + +right + + align:start position:0% +right + + + align:start position:0% +right +which means that if the ensemble rotates + + align:start position:0% +which means that if the ensemble rotates + + + align:start position:0% +which means that if the ensemble rotates +all the points rotate you know how if + + align:start position:0% +all the points rotate you know how if + + + align:start position:0% +all the points rotate you know how if +you look at the stars + + align:start position:0% +you look at the stars + + + align:start position:0% +you look at the stars +and you kind of do those time + + align:start position:0% +and you kind of do those time + + + align:start position:0% +and you kind of do those time +lapse things they're all in scrap + + align:start position:0% +lapse things they're all in scrap + + + align:start position:0% +lapse things they're all in scrap +circles time lapse photographs right + + align:start position:0% +circles time lapse photographs right + + + align:start position:0% +circles time lapse photographs right +that's kind of what i'm doing here i'm + + align:start position:0% +that's kind of what i'm doing here i'm + + + align:start position:0% +that's kind of what i'm doing here i'm +saying look + + align:start position:0% +saying look + + + align:start position:0% +saying look +whatever the velocity of a particle is + + align:start position:0% +whatever the velocity of a particle is + + + align:start position:0% +whatever the velocity of a particle is +it must be related to all the other + + align:start position:0% +it must be related to all the other + + + align:start position:0% +it must be related to all the other +particles in the following way which is + + align:start position:0% +particles in the following way which is + + + align:start position:0% +particles in the following way which is +they're all center of mass velocity plus + + align:start position:0% +they're all center of mass velocity plus + + + align:start position:0% +they're all center of mass velocity plus +omega cross their distance from the + + align:start position:0% +omega cross their distance from the + + + align:start position:0% +omega cross their distance from the +center of mass + + align:start position:0% +center of mass + + + align:start position:0% +center of mass +as a vector get it + + align:start position:0% +as a vector get it + + + align:start position:0% +as a vector get it +are you okay with this + + align:start position:0% +are you okay with this + + + align:start position:0% +are you okay with this +if you're not you stop me + + align:start position:0% + + + + align:start position:0% + +you're saying where is bvi that's yeah + + align:start position:0% +you're saying where is bvi that's yeah + + + align:start position:0% +you're saying where is bvi that's yeah +that makes sense + + align:start position:0% +that makes sense + + + align:start position:0% +that makes sense +bvi zero because it's not moving with + + align:start position:0% +bvi zero because it's not moving with + + + align:start position:0% +bvi zero because it's not moving with +respect to b i'm not writing up the + + align:start position:0% +respect to b i'm not writing up the + + + align:start position:0% +respect to b i'm not writing up the +whole uh + + align:start position:0% +whole uh + + + align:start position:0% +whole uh +formula here all right if you wanted to + + align:start position:0% +formula here all right if you wanted to + + + align:start position:0% +formula here all right if you wanted to +use the entire formula it should be your + + align:start position:0% +use the entire formula it should be your + + + align:start position:0% +use the entire formula it should be your +right + + align:start position:0% +right + + + align:start position:0% +right +it should be a + + align:start position:0% +it should be a + + + align:start position:0% +it should be a +v + + align:start position:0% +v + + + align:start position:0% +v +c + + align:start position:0% +c + + + align:start position:0% +c +plus b + + align:start position:0% +plus b + + + align:start position:0% +plus b +v i + + align:start position:0% +v i + + + align:start position:0% +v i +plus a omega p b cross + + align:start position:0% +plus a omega p b cross + + + align:start position:0% +plus a omega p b cross +r right + + align:start position:0% +r right + + + align:start position:0% +r right +b is zero thank you rj that's i think + + align:start position:0% +b is zero thank you rj that's i think + + + align:start position:0% +b is zero thank you rj that's i think +that's where you were going because it's + + align:start position:0% +that's where you were going because it's + + + align:start position:0% +that's where you were going because it's +rigid so if you're sitting on the + + align:start position:0% +rigid so if you're sitting on the + + + align:start position:0% +rigid so if you're sitting on the +ensemble + + align:start position:0% +ensemble + + + align:start position:0% +ensemble +right + + align:start position:0% +right + + + align:start position:0% +right +getting the those particles aren't + + align:start position:0% +getting the those particles aren't + + + align:start position:0% +getting the those particles aren't +moving + + align:start position:0% +moving + + + align:start position:0% +moving +okay is anyone good with this + + align:start position:0% + + + + align:start position:0% + +sure + + align:start position:0% + + + + align:start position:0% + +so if you call the ensemble a framework + + align:start position:0% +so if you call the ensemble a framework + + + align:start position:0% +so if you call the ensemble a framework +reference e + + align:start position:0% +reference e + + + align:start position:0% +reference e +then the kind of the velocity version of + + align:start position:0% +then the kind of the velocity version of + + + align:start position:0% +then the kind of the velocity version of +the super ultra magic formula would be + + align:start position:0% +the super ultra magic formula would be + + + align:start position:0% +the super ultra magic formula would be +a + + align:start position:0% +a + + + align:start position:0% +a +velocity of i + + align:start position:0% +velocity of i + + + align:start position:0% +velocity of i +is equal to a + + align:start position:0% +is equal to a + + + align:start position:0% +is equal to a +velocity of this some reference point c + + align:start position:0% +velocity of this some reference point c + + + align:start position:0% +velocity of this some reference point c +plus b + + align:start position:0% +plus b + + + align:start position:0% +plus b +velocity of i + + align:start position:0% +velocity of i + + + align:start position:0% +velocity of i +plus + + align:start position:0% +plus + + + align:start position:0% +plus +a + + align:start position:0% +a + + + align:start position:0% +a +actually we call be right the ensemble i + + align:start position:0% +actually we call be right the ensemble i + + + align:start position:0% +actually we call be right the ensemble i +just use e + + align:start position:0% +just use e + + + align:start position:0% +just use e +omega b + + align:start position:0% +omega b + + + align:start position:0% +omega b +e sorry e + + align:start position:0% +e sorry e + + + align:start position:0% +e sorry e +cross + + align:start position:0% +cross + + + align:start position:0% +cross +r + + align:start position:0% +r + + + align:start position:0% +r +c i + + align:start position:0% + + + + align:start position:0% + +you understand + + align:start position:0% +you understand + + + align:start position:0% +you understand +so space shuttle + + align:start position:0% +so space shuttle + + + align:start position:0% +so space shuttle +right + + align:start position:0% +right + + + align:start position:0% +right +a point on the space shuttle space + + align:start position:0% +a point on the space shuttle space + + + align:start position:0% +a point on the space shuttle space +shuttle is e endeavor right + + align:start position:0% +shuttle is e endeavor right + + + align:start position:0% +shuttle is e endeavor right +c is some point on it + + align:start position:0% +c is some point on it + + + align:start position:0% +c is some point on it +we want to find the velocity of a + + align:start position:0% +we want to find the velocity of a + + + align:start position:0% +we want to find the velocity of a +astronaut who's running away from + + align:start position:0% +astronaut who's running away from + + + align:start position:0% +astronaut who's running away from +you know the central space shuttle + + align:start position:0% +you know the central space shuttle + + + align:start position:0% +you know the central space shuttle +with + + align:start position:0% +with + + + align:start position:0% +with +evi velocity + + align:start position:0% +evi velocity + + + align:start position:0% +evi velocity +right + + align:start position:0% + + + + align:start position:0% + +it doesn't matter this formula holds for + + align:start position:0% +it doesn't matter this formula holds for + + + align:start position:0% +it doesn't matter this formula holds for +any reference point + + align:start position:0% +any reference point + + + align:start position:0% +any reference point +but as it happens i'm going to do + + align:start position:0% +but as it happens i'm going to do + + + align:start position:0% +but as it happens i'm going to do +everything about center of mass of the + + align:start position:0% +everything about center of mass of the + + + align:start position:0% +everything about center of mass of the +space shuttle + + align:start position:0% +space shuttle + + + align:start position:0% +space shuttle +this formula holds right but this term + + align:start position:0% +this formula holds right but this term + + + align:start position:0% +this formula holds right but this term +is going to vanish + + align:start position:0% +is going to vanish + + + align:start position:0% +is going to vanish +because it's a rigid body + + align:start position:0% +because it's a rigid body + + + align:start position:0% +because it's a rigid body +right with respect to central mass on a + + align:start position:0% +right with respect to central mass on a + + + align:start position:0% +right with respect to central mass on a +frame attached to the ensemble + + align:start position:0% +frame attached to the ensemble + + + align:start position:0% +frame attached to the ensemble +the point i isn't moving + + align:start position:0% +the point i isn't moving + + + align:start position:0% +the point i isn't moving +get it + + align:start position:0% +get it + + + align:start position:0% +get it +this term is not zero because the whole + + align:start position:0% +this term is not zero because the whole + + + align:start position:0% +this term is not zero because the whole +ensemble is moving + + align:start position:0% +ensemble is moving + + + align:start position:0% +ensemble is moving +and this term is not zero + + align:start position:0% +and this term is not zero + + + align:start position:0% +and this term is not zero +get it + + align:start position:0% +get it + + + align:start position:0% +get it +just using the super magic formula + + align:start position:0% +just using the super magic formula + + + align:start position:0% +just using the super magic formula +answer your question + + align:start position:0% +answer your question + + + align:start position:0% +answer your question +okay + + align:start position:0% + + + + align:start position:0% + +that's this + + align:start position:0% + + + + align:start position:0% + +so let's rewrite it + + align:start position:0% +so let's rewrite it + + + align:start position:0% +so let's rewrite it +i have one see + + align:start position:0% +i have one see + + + align:start position:0% +i have one see +10 12 minutes + + align:start position:0% +10 12 minutes + + + align:start position:0% +10 12 minutes +i'm going to rewrite this now is equal + + align:start position:0% +i'm going to rewrite this now is equal + + + align:start position:0% +i'm going to rewrite this now is equal +to sigma + + align:start position:0% +to sigma + + + align:start position:0% +to sigma +i is equal to 1 + + align:start position:0% +i is equal to 1 + + + align:start position:0% +i is equal to 1 +through n + + align:start position:0% +through n + + + align:start position:0% +through n +r + + align:start position:0% + + + + align:start position:0% + +sorry mi + + align:start position:0% +sorry mi + + + align:start position:0% +sorry mi +r q i + + align:start position:0% +r q i + + + align:start position:0% +r q i +just pull the m out + + align:start position:0% +just pull the m out + + + align:start position:0% +just pull the m out +cross can you help me out here folks + + align:start position:0% + + + + align:start position:0% + +just to be clear the c is the center of + + align:start position:0% +just to be clear the c is the center of + + + align:start position:0% +just to be clear the c is the center of +what do i get here + + align:start position:0% + + + + align:start position:0% + +right + + align:start position:0% + + + + align:start position:0% + +plus + + align:start position:0% + + + + align:start position:0% + +sigma + + align:start position:0% +sigma + + + align:start position:0% +sigma +pi is equal to 1 to n i'm just expanding + + align:start position:0% +pi is equal to 1 to n i'm just expanding + + + align:start position:0% +pi is equal to 1 to n i'm just expanding +it out the two additions + + align:start position:0% + + + + align:start position:0% + +again i'm going to pull the mi + + align:start position:0% + + + + align:start position:0% + +out what + + align:start position:0% + + + + align:start position:0% + +sorry + + align:start position:0% + + + + align:start position:0% + +yeah i'll put the mi out + + align:start position:0% +yeah i'll put the mi out + + + align:start position:0% +yeah i'll put the mi out +and i'm going to rewrite this guy again + + align:start position:0% +and i'm going to rewrite this guy again + + + align:start position:0% +and i'm going to rewrite this guy again +in terms of rci + + align:start position:0% +in terms of rci + + + align:start position:0% +in terms of rci +how can i rewrite this guy in terms of + + align:start position:0% +how can i rewrite this guy in terms of + + + align:start position:0% +how can i rewrite this guy in terms of +rci + + align:start position:0% + + + + align:start position:0% + +anybody our qi + + align:start position:0% +anybody our qi + + + align:start position:0% +anybody our qi +is equal to rqc plus rci all right + + align:start position:0% +is equal to rqc plus rci all right + + + align:start position:0% +is equal to rqc plus rci all right +basically i'm going to take the vector + + align:start position:0% +basically i'm going to take the vector + + + align:start position:0% +basically i'm going to take the vector +from + + align:start position:0% + + + + align:start position:0% + +whoa + + align:start position:0% + + + + align:start position:0% + +rci our our qi is this vector + + align:start position:0% +rci our our qi is this vector + + + align:start position:0% +rci our our qi is this vector +right the center of mass is some point + + align:start position:0% +right the center of mass is some point + + + align:start position:0% +right the center of mass is some point +here c + + align:start position:0% +here c + + + align:start position:0% +here c +so i'm going to go this way + + align:start position:0% +so i'm going to go this way + + + align:start position:0% +so i'm going to go this way +i want to express everything in terms of + + align:start position:0% +i want to express everything in terms of + + + align:start position:0% +i want to express everything in terms of +this guy + + align:start position:0% +this guy + + + align:start position:0% +this guy +so this is equal to + + align:start position:0% +so this is equal to + + + align:start position:0% +so this is equal to +r + + align:start position:0% + + + + align:start position:0% + +q c + + align:start position:0% +q c + + + align:start position:0% +q c +plus r + + align:start position:0% +plus r + + + align:start position:0% +plus r +c i + + align:start position:0% + + + + align:start position:0% + +this + + align:start position:0% + + + + align:start position:0% + +what i just do here + + align:start position:0% + + + + align:start position:0% + +that's this guy + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +and then i have + + align:start position:0% +and then i have + + + align:start position:0% +and then i have +cross this term + + align:start position:0% + + + + align:start position:0% + +i'll just summarize in a second okay + + align:start position:0% + + + + align:start position:0% + +here's what i did first step + + align:start position:0% +here's what i did first step + + + align:start position:0% +here's what i did first step +i wrote it you know just the definition + + align:start position:0% +i wrote it you know just the definition + + + align:start position:0% +i wrote it you know just the definition +of ahq + + align:start position:0% +of ahq + + + align:start position:0% +of ahq +a h e by e around q + + align:start position:0% +a h e by e around q + + + align:start position:0% +a h e by e around q +then i wrote rewrote this then i + + align:start position:0% +then i wrote rewrote this then i + + + align:start position:0% +then i wrote rewrote this then i +uh rewrote avi in terms of the center of + + align:start position:0% +uh rewrote avi in terms of the center of + + + align:start position:0% +uh rewrote avi in terms of the center of +mass velocity + + align:start position:0% +mass velocity + + + align:start position:0% +mass velocity +and angular + + align:start position:0% +and angular + + + align:start position:0% +and angular +velocity + + align:start position:0% +velocity + + + align:start position:0% +velocity +i took this term out here + + align:start position:0% +i took this term out here + + + align:start position:0% +i took this term out here +and then the remaining that's this term + + align:start position:0% +and then the remaining that's this term + + + align:start position:0% +and then the remaining that's this term +i split it up this way + + align:start position:0% +i split it up this way + + + align:start position:0% +i split it up this way +just + + align:start position:0% +just + + + align:start position:0% +just +drudgery + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +it's just it's just drudgery i'm not + + align:start position:0% +it's just it's just drudgery i'm not + + + align:start position:0% +it's just it's just drudgery i'm not +doing anything particularly profound + + align:start position:0% +doing anything particularly profound + + + align:start position:0% +doing anything particularly profound +here just vectors + + align:start position:0% +here just vectors + + + align:start position:0% +here just vectors +express a vector this way that way all + + align:start position:0% +express a vector this way that way all + + + align:start position:0% +express a vector this way that way all +right + + align:start position:0% +right + + + align:start position:0% +right +and in some ways you can't even see why + + align:start position:0% +and in some ways you can't even see why + + + align:start position:0% +and in some ways you can't even see why +i'm doing it until you get to the end + + align:start position:0% +i'm doing it until you get to the end + + + align:start position:0% +i'm doing it until you get to the end +point you go ah or hopefully you'll go + + align:start position:0% +point you go ah or hopefully you'll go + + + align:start position:0% +point you go ah or hopefully you'll go +ah if you're not sleeping all right + + align:start position:0% +ah if you're not sleeping all right + + + align:start position:0% +ah if you're not sleeping all right +so + + align:start position:0% +so + + + align:start position:0% +so +this rewrites two + + align:start position:0% + + + + align:start position:0% + +right this is actually the definition of + + align:start position:0% +right this is actually the definition of + + + align:start position:0% +right this is actually the definition of +center of mass at some level + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +plus this rewrites to + + align:start position:0% + + + + align:start position:0% + +a really really ugly term + + align:start position:0% + + + + align:start position:0% + +this term + + align:start position:0% +this term + + + align:start position:0% +this term +plus + + align:start position:0% +plus + + + align:start position:0% +plus +a term which will look ugly for a moment + + align:start position:0% +a term which will look ugly for a moment + + + align:start position:0% +a term which will look ugly for a moment +but is actually very elegant + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% + + + + align:start position:0% + +i just expanded that out + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so just so you know from here to here + + align:start position:0% +so just so you know from here to here + + + align:start position:0% +so just so you know from here to here +it's just expanding rewriting there's + + align:start position:0% +it's just expanding rewriting there's + + + align:start position:0% +it's just expanding rewriting there's +nothing profound if you fell asleep and + + align:start position:0% +nothing profound if you fell asleep and + + + align:start position:0% +nothing profound if you fell asleep and +you just woke up it's okay i didn't miss + + align:start position:0% +you just woke up it's okay i didn't miss + + + align:start position:0% +you just woke up it's okay i didn't miss +much + + align:start position:0% +much + + + align:start position:0% +much +right + + align:start position:0% +right + + + align:start position:0% +right +so that is uh simply rewriting uh + + align:start position:0% +so that is uh simply rewriting uh + + + align:start position:0% +so that is uh simply rewriting uh +the angular momentum of ensemble e about + + align:start position:0% +the angular momentum of ensemble e about + + + align:start position:0% +the angular momentum of ensemble e about +point q in terms of + + align:start position:0% +point q in terms of + + + align:start position:0% +point q in terms of +center of mass distance from centromere + + align:start position:0% +center of mass distance from centromere + + + align:start position:0% +center of mass distance from centromere +stuff like that + + align:start position:0% +stuff like that + + + align:start position:0% +stuff like that +okay + + align:start position:0% +okay + + + align:start position:0% +okay +now + + align:start position:0% +now + + + align:start position:0% +now +we get to the fun part + + align:start position:0% + + + + align:start position:0% + +this is in fact + + align:start position:0% +this is in fact + + + align:start position:0% +this is in fact +nothing more + + align:start position:0% +nothing more + + + align:start position:0% +nothing more +than the distance of the center of mass + + align:start position:0% +than the distance of the center of mass + + + align:start position:0% +than the distance of the center of mass +from point q + + align:start position:0% +from point q + + + align:start position:0% +from point q +cross product with what anyone + + align:start position:0% + + + + align:start position:0% + +anyone + + align:start position:0% + + + + align:start position:0% + +hmm + + align:start position:0% + + + + align:start position:0% + +it's the angle it's the linear momentum + + align:start position:0% + + + + align:start position:0% + +yeah that's cute sorry + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +now this guy + + align:start position:0% +now this guy + + + align:start position:0% +now this guy +i'm not even going to bother to expand + + align:start position:0% +i'm not even going to bother to expand + + + align:start position:0% +i'm not even going to bother to expand +it because it's just a mess and there's + + align:start position:0% +it because it's just a mess and there's + + + align:start position:0% +it because it's just a mess and there's +no saving it right + + align:start position:0% + + + + align:start position:0% + +okay that's this guy this is just no i + + align:start position:0% +okay that's this guy this is just no i + + + align:start position:0% +okay that's this guy this is just no i +can't simplify it even i can't do it + + align:start position:0% +can't simplify it even i can't do it + + + align:start position:0% +can't simplify it even i can't do it +now + + align:start position:0% +now + + + align:start position:0% +now +this is very interesting this is called + + align:start position:0% +this is very interesting this is called + + + align:start position:0% +this is very interesting this is called +the vector triple product + + align:start position:0% +the vector triple product + + + align:start position:0% +the vector triple product +here's a beautiful little formula + + align:start position:0% +here's a beautiful little formula + + + align:start position:0% +here's a beautiful little formula +if you have something like this + + align:start position:0% +if you have something like this + + + align:start position:0% +if you have something like this +a vector a across a vector b + + align:start position:0% +a vector a across a vector b + + + align:start position:0% +a vector a across a vector b +across a vector c + + align:start position:0% +across a vector c + + + align:start position:0% +across a vector c +this is called a vector triple product + + align:start position:0% +this is called a vector triple product + + + align:start position:0% +this is called a vector triple product +you can solve you can rewrite this as + + align:start position:0% + + + + align:start position:0% + +did you know that + + align:start position:0% +did you know that + + + align:start position:0% +did you know that +have you seen this before + + align:start position:0% +have you seen this before + + + align:start position:0% +have you seen this before +it's a vector identity you've seen it in + + align:start position:0% +it's a vector identity you've seen it in + + + align:start position:0% +it's a vector identity you've seen it in +map trust me you've forgotten it's + + align:start position:0% +map trust me you've forgotten it's + + + align:start position:0% +map trust me you've forgotten it's +called the vector triple product you can + + align:start position:0% +called the vector triple product you can + + + align:start position:0% +called the vector triple product you can +prove it easily i'm not going to prove + + align:start position:0% +prove it easily i'm not going to prove + + + align:start position:0% +prove it easily i'm not going to prove +it it's a well-known mathematical thing + + align:start position:0% +it it's a well-known mathematical thing + + + align:start position:0% +it it's a well-known mathematical thing +we'll just call call it here + + align:start position:0% +we'll just call call it here + + + align:start position:0% +we'll just call call it here +so + + align:start position:0% +so + + + align:start position:0% +so +with that you can rewrite this + + align:start position:0% +with that you can rewrite this + + + align:start position:0% +with that you can rewrite this +okay that's the vector triple product + + align:start position:0% +okay that's the vector triple product + + + align:start position:0% +okay that's the vector triple product +formula + + align:start position:0% + + + + align:start position:0% + +any three vectors so if you rewrite it + + align:start position:0% +any three vectors so if you rewrite it + + + align:start position:0% +any three vectors so if you rewrite it +here's what you get + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so this is the mess that we've just + + align:start position:0% +so this is the mess that we've just + + + align:start position:0% +so this is the mess that we've just +inherited and i'm going to clean up the + + align:start position:0% +inherited and i'm going to clean up the + + + align:start position:0% +inherited and i'm going to clean up the +mess + + align:start position:0% +mess + + + align:start position:0% +mess +okay + + align:start position:0% +okay + + + align:start position:0% +okay +first of all + + align:start position:0% +first of all + + + align:start position:0% +first of all +in a tour we're looking at two + + align:start position:0% +in a tour we're looking at two + + + align:start position:0% +in a tour we're looking at two +dimensions by the way this can be + + align:start position:0% +dimensions by the way this can be + + + align:start position:0% +dimensions by the way this can be +generalized to three dimensions + + align:start position:0% +generalized to three dimensions + + + align:start position:0% +generalized to three dimensions +what happens to this term + + align:start position:0% +what happens to this term + + + align:start position:0% +what happens to this term +in two dimensions + + align:start position:0% + + + + align:start position:0% + +position vector of points i with respect + + align:start position:0% +position vector of points i with respect + + + align:start position:0% +position vector of points i with respect +to the center of mass + + align:start position:0% +to the center of mass + + + align:start position:0% +to the center of mass +dot product with the angular velocity + + align:start position:0% +dot product with the angular velocity + + + align:start position:0% +dot product with the angular velocity +what happens to this term + + align:start position:0% +what happens to this term + + + align:start position:0% +what happens to this term +vanishes why because if this is the + + align:start position:0% +vanishes why because if this is the + + + align:start position:0% +vanishes why because if this is the +plane + + align:start position:0% +plane + + + align:start position:0% +plane +the angular velocity points this way + + align:start position:0% +the angular velocity points this way + + + align:start position:0% +the angular velocity points this way +position vectors are all in the plane + + align:start position:0% +position vectors are all in the plane + + + align:start position:0% +position vectors are all in the plane +right and these days the dot product of + + align:start position:0% +right and these days the dot product of + + + align:start position:0% +right and these days the dot product of +two orthogonal vectors is zero + + align:start position:0% +two orthogonal vectors is zero + + + align:start position:0% +two orthogonal vectors is zero +right + + align:start position:0% +right + + + align:start position:0% +right +so this is zero + + align:start position:0% + + + + align:start position:0% + +yeah + + align:start position:0% +yeah + + + align:start position:0% +yeah +yeah + + align:start position:0% +yeah + + + align:start position:0% +yeah +so this is i use the scalar dot cross + + align:start position:0% +so this is i use the scalar dot cross + + + align:start position:0% +so this is i use the scalar dot cross +you know the vector dot uh + + align:start position:0% +you know the vector dot uh + + + align:start position:0% +you know the vector dot uh +triple product rule to write rewrite + + align:start position:0% +triple product rule to write rewrite + + + align:start position:0% +triple product rule to write rewrite +this this is our + + align:start position:0% +this this is our + + + align:start position:0% +this this is our +position vector + + align:start position:0% +position vector + + + align:start position:0% +position vector +of point i from the center of mass + + align:start position:0% +of point i from the center of mass + + + align:start position:0% +of point i from the center of mass +it's in the plane of the blackboard + + align:start position:0% +it's in the plane of the blackboard + + + align:start position:0% +it's in the plane of the blackboard +angular velocity is outwards yep + + align:start position:0% + + + + align:start position:0% + +maybe i wrote it in the wrong order it's + + align:start position:0% +maybe i wrote it in the wrong order it's + + + align:start position:0% +maybe i wrote it in the wrong order it's +fine okay uh it it doesn't matter only + + align:start position:0% +fine okay uh it it doesn't matter only + + + align:start position:0% +fine okay uh it it doesn't matter only +because it goes to zero but it does + + align:start position:0% +because it goes to zero but it does + + + align:start position:0% +because it goes to zero but it does +matter in the sense that i screwed up so + + align:start position:0% +matter in the sense that i screwed up so + + + align:start position:0% +matter in the sense that i screwed up so +in what way did i + + align:start position:0% +in what way did i + + + align:start position:0% +in what way did i +what did i what was the mistake + + align:start position:0% + + + + align:start position:0% + +you have your parentheses and the second + + align:start position:0% +you have your parentheses and the second + + + align:start position:0% +you have your parentheses and the second +part as opposed to the first two + + align:start position:0% +part as opposed to the first two + + + align:start position:0% +part as opposed to the first two +ah good point we'll have to check let me + + align:start position:0% +ah good point we'll have to check let me + + + align:start position:0% +ah good point we'll have to check let me +check okay i don't want to just because + + align:start position:0% +check okay i don't want to just because + + + align:start position:0% +check okay i don't want to just because +i'm running out of time it turns out my + + align:start position:0% +i'm running out of time it turns out my + + + align:start position:0% +i'm running out of time it turns out my +answer is wrong so i've made two + + align:start position:0% +answer is wrong so i've made two + + + align:start position:0% +answer is wrong so i've made two +mistakes and cancelled them out or maybe + + align:start position:0% +mistakes and cancelled them out or maybe + + + align:start position:0% +mistakes and cancelled them out or maybe +it doesn't matter i can just look at + + align:start position:0% +it doesn't matter i can just look at + + + align:start position:0% +it doesn't matter i can just look at +that + + align:start position:0% +that + + + align:start position:0% +that +yeah we'll just confirm that thank you + + align:start position:0% +yeah we'll just confirm that thank you + + + align:start position:0% +yeah we'll just confirm that thank you +all right + + align:start position:0% + + + + align:start position:0% + +but the point is this term vanishes + + align:start position:0% +but the point is this term vanishes + + + align:start position:0% +but the point is this term vanishes +anyway because it'll be a dot product + + align:start position:0% +anyway because it'll be a dot product + + + align:start position:0% +anyway because it'll be a dot product +anyone recognize this term + + align:start position:0% + + + + align:start position:0% + +m r squared of omega + + align:start position:0% +m r squared of omega + + + align:start position:0% +m r squared of omega +so what is m r squared + + align:start position:0% +so what is m r squared + + + align:start position:0% +so what is m r squared +all right okay so this is i in its + + align:start position:0% +all right okay so this is i in its + + + align:start position:0% +all right okay so this is i in its +primordial form + + align:start position:0% +primordial form + + + align:start position:0% +primordial form +anyone recognize this term + + align:start position:0% +anyone recognize this term + + + align:start position:0% +anyone recognize this term +yeah it's a terrible term this term + + align:start position:0% +yeah it's a terrible term this term + + + align:start position:0% +yeah it's a terrible term this term +whatever right + + align:start position:0% +whatever right + + + align:start position:0% +whatever right +so + + align:start position:0% +so + + + align:start position:0% +so +the point i want to make is + + align:start position:0% +the point i want to make is + + + align:start position:0% +the point i want to make is +these guys only vanish under certain + + align:start position:0% +these guys only vanish under certain + + + align:start position:0% +these guys only vanish under certain +circumstances and that's the pitfall you + + align:start position:0% +circumstances and that's the pitfall you + + + align:start position:0% +circumstances and that's the pitfall you +need to be aware of + + align:start position:0% +need to be aware of + + + align:start position:0% +need to be aware of +all right + + align:start position:0% +all right + + + align:start position:0% +all right +and for example + + align:start position:0% +and for example + + + align:start position:0% +and for example +if + + align:start position:0% +if + + + align:start position:0% +if +q the point about which you're taking + + align:start position:0% +q the point about which you're taking + + + align:start position:0% +q the point about which you're taking +this the angular momentum + + align:start position:0% +this the angular momentum + + + align:start position:0% +this the angular momentum +is equal to is the same as the center of + + align:start position:0% +is equal to is the same as the center of + + + align:start position:0% +is equal to is the same as the center of +mass + + align:start position:0% +mass + + + align:start position:0% +mass +this term vanishes + + align:start position:0% + + + + align:start position:0% + +this term vanishes + + align:start position:0% +this term vanishes + + + align:start position:0% +this term vanishes +get it because this is rqc + + align:start position:0% +get it because this is rqc + + + align:start position:0% +get it because this is rqc +right + + align:start position:0% +right + + + align:start position:0% +right +so if q is the center of mass + + align:start position:0% +so if q is the center of mass + + + align:start position:0% +so if q is the center of mass +then + + align:start position:0% +then + + + align:start position:0% +then +what we have just shown is + + align:start position:0% +what we have just shown is + + + align:start position:0% +what we have just shown is +a + + align:start position:0% +a + + + align:start position:0% +a +h + + align:start position:0% +h + + + align:start position:0% +h +ensemble about point out where the + + align:start position:0% +ensemble about point out where the + + + align:start position:0% +ensemble about point out where the +center of mass + + align:start position:0% +center of mass + + + align:start position:0% +center of mass +is equal to + + align:start position:0% +is equal to + + + align:start position:0% +is equal to +i + + align:start position:0% +i + + + align:start position:0% +i +that in fact my friends is the + + align:start position:0% +that in fact my friends is the + + + align:start position:0% +that in fact my friends is the +definition of i + + align:start position:0% +definition of i + + + align:start position:0% +definition of i +that is the definition of i + + align:start position:0% + + + + align:start position:0% + +a omega b + + align:start position:0% + + + + align:start position:0% + +got it + + align:start position:0% +got it + + + align:start position:0% +got it +and then if that holds + + align:start position:0% +and then if that holds + + + align:start position:0% +and then if that holds +and only if that holds can you also say + + align:start position:0% +and only if that holds can you also say + + + align:start position:0% +and only if that holds can you also say +that the total torque on the ensemble + + align:start position:0% +that the total torque on the ensemble + + + align:start position:0% +that the total torque on the ensemble +which is the rate of change of that + + align:start position:0% +which is the rate of change of that + + + align:start position:0% +which is the rate of change of that +about point q + + align:start position:0% +about point q + + + align:start position:0% +about point q +is equal to what + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +by the way in a continuum a summation is + + align:start position:0% +by the way in a continuum a summation is + + + align:start position:0% +by the way in a continuum a summation is +an integral so when you do integrals + + align:start position:0% +an integral so when you do integrals + + + align:start position:0% +an integral so when you do integrals +it's the same thing + + align:start position:0% +it's the same thing + + + align:start position:0% +it's the same thing +but for very tiny particles + + align:start position:0% +but for very tiny particles + + + align:start position:0% +but for very tiny particles +but in a continuum so it would become + + align:start position:0% +but in a continuum so it would become + + + align:start position:0% +but in a continuum so it would become +and this will be done in recitation + + align:start position:0% +and this will be done in recitation + + + align:start position:0% +and this will be done in recitation +it'll become dm you know it's an + + align:start position:0% +it'll become dm you know it's an + + + align:start position:0% +it'll become dm you know it's an +integral right + + align:start position:0% + + + + align:start position:0% + +so the definition of of of moment of + + align:start position:0% +so the definition of of of moment of + + + align:start position:0% +so the definition of of of moment of +inertia is this guy + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +yes same + + align:start position:0% + + + + align:start position:0% + +velocities + + align:start position:0% + + + + align:start position:0% + +if i can't answer this question + + align:start position:0% +if i can't answer this question + + + align:start position:0% +if i can't answer this question +i'll answer it i mean if i think about + + align:start position:0% +i'll answer it i mean if i think about + + + align:start position:0% +i'll answer it i mean if i think about +it i'll answer it in class next week \ No newline at end of file diff --git a/up3zP2z81SE.txt b/up3zP2z81SE.txt new file mode 100644 index 0000000000000000000000000000000000000000..91db0762168c02745557d6825677e8bf6d9de8c6 --- /dev/null +++ b/up3zP2z81SE.txt @@ -0,0 +1,2775 @@ +SPEAKER: The following content +is provided under a Creative + +Commons License. + +Your support will help MIT +OpenCourseWare continue to + +offer high quality educational +resources for free. + +To make a donation or view +additional materials from + +hundreds of MIT courses visit +MIT OpenCourseWare at + +ocw.mit.edu. + +PROFESSOR: This Wednesday +will be the first + +celebration of learning. + +Test 1 on Wednesday, October 7, +you will write during the + +normal class time. + +So you'll have 50 minutes. + +And we want to have a little +bit of comfort here, so you + +won't be sitting +cheek to jowl. + +So before long I'll have +the room assignment. + +So some of you will +write in here. + +We'll have fewer people than +seats so that there'll be + +vacancies next to each person. + +And then some will write in a +few of the other locations, + +probably 26-100 and the gym +above the Walker Memorial. + +And we'll get that out to you. + +And next week on the 6th we +will have no weekly quiz, + +because enough celebrating. + +No point in testing you on the +6th and then on the 7th. + +There will be, of course, +the mini-celebration + +tomorrow, quiz 3. + +And I'll be available for office +hours later today. + +Oh, and the coverage, just to +remove the mystery, will be + +right up to the 7th +of October. + +I've been doing this for over 30 +years and I've learned that + +in order to inspire interest on +the part of the student it + +really pays to have the coverage +of the celebration + +extend up to the lecture +before the celebration. + +Now obviously I'm not going to +drill deep on something I + +taught you on October 5, but +it would be a good idea to + +stay awake during all of the +lectures between now and then. + +So last day we talked +about ionic bonding. + +And ionic bonding occurs with +electrostatic attraction + +between ions that have formed +through electron transfer. + +And we saw the energy of the +ion pair given by this + +formula, where we have +Coulomb's law + +with the Born exponent. + +And then this is plotted. + +This is E at r equals r0, and we +learned that there were two + +terms. The attractive term, +which is the Coulombic force + +here shown. + +And then there's a repulsive +term, which results from + +electron-electron interaction +when the two lines get very, + +very close together. + +And this is taken +from your text. + +And I think they did a very nice +job here of illustrating + +as you go to high values of r +they're depicting that you + +have the ions separated by +considerable distance. + +And there's a certain +amount of stored + +energy, but not a lot. + +And then if you go much, much +closer than the hard sphere + +sum of the ionic radii, I think +they're depicting here + +that there's some squashing +of the electron clouds. + +And you can see that the energy +has gone way, way up. + +So this is an unfavorable +situation, meaning that the + +energy here is greater than 0. + +And there's a sweet spot here +at 236 picometers, which + +represents the ideal location. + +And that is the sum of the +radius of the sodium ion and + +the radius of the +chloride ion. + +And so you can see how +energy tracks. + +And if you go far, far, far +away to the point where + +they're at infinite separation, + +there's no energy stored. + +So everything makes sense. + +And then we said, well what +happens if we keep packing + +these things? + +We rationalized that they would +continue to do so and + +ultimately form a 3-dimensional +crystal. + +And so you can see there's a +lot of similarity between + +what's above and what's +down here. + +This has been written +for a 1-1 system. + +In other words, a cation plus +1 and an anion minus 1. + +But it could be mediated +by the valences. + +And what we have here is +the structure factor. + +This Madelung constant tells us +how much we get decrease in + +the energy of the system +by going to a + +3-dimensional array. + +So depending on the atomic +arrangement we'll have a + +different value of Madelung +constant. + +We saw that for sodium chloride +the value is 1.7476. + +And different crystals have +different things. + +And what determines the +crystal structure? + +It's a combination of +the size of the two + +ions and their valence. + +So what we saw for sodium +chloride, this + +is a structure type. + +So obviously sodium chloride +is sodium chloride crystal + +structure, but there is an +entire suite of compounds that + +have radius ratios and charges +that end up with a sodium + +chloride type crystal +structure. + +And then towards the end we +started looking at the + +Born-Haber Cycle. + +And the purpose of the +Born-Haber Cycle was to give + +us a sense of scale of the +various constituents in the + +formation of a crystal. + +And what we noted, the takeaway +message from the + +Born-Haber Cycle, is that this +enthalpy of crystallization, + +which is basically this +term here, is huge. + +It's huge. + +It was the big component of the +energy required to form + +the crystal. + +It's large and it is negative. + +So what I want to do today +is start by talking about + +shortcomings of the business +of ionic bonding. + +See, how did we get +to ionic bonding? + +We started with this idea +of octet stability. + +Octet stability was +the driving idea + +behind all of this. + +Octet stability, and in the case +of ionic bonding this was + +via electron transfer. + +And so that got us a long way, +but it has its limitations. + +So let's put up some new data. + +So suppose I look at compounds +like H2, N2, O2. + +Do these things form +ionic bonds? + +How does octet stability +play here? + +And so let's start by +looking at hydrogen. + +So if we took hydrogen and +started with atomic hydrogen + +and added an electron to it, +then we would form an anion + +known as H minus. + +And H minus looks pretty good +because it's isoelectronic + +with helium. + +So maybe this isn't going +to be so bad a day. + +But if we're going to have +a bond then we need + +to form an H plus. + +So let's do that. + +So that would be, then, H goes +to H plus, plus an electron. + +And that's really nothing +more than a proton. + +So that doesn't look +too appealing. + +That's probably a high +energy state. + +And besides, in the same +location at the same time-- + +in other words, same +temperature, same conditions-- + +half of the hydrogens have to +acquire electrons and half of + +the hydrogens have to +lose electrons. + +And that's not going +to happen. + +They're either going to have a +propensity for electron gain + +or a propensity for +electron loss. + +So it looks like ionic bonding +is not going to help us + +explain the formation +of molecules such as + +H2, N2, and so on. + +So who came to the rescue +in this case to get + +us out of the conundrum? + +G.N. + +Lewis. + +G.N. + +Lewis was actually born in +Weymouth, Massachusetts and he + +finished his PhD at +Harvard in 1899. + +And then, like so many Americans +of the day, went off + +to Europe and he postdoc'd +in Europe for a while. + +And then he came back and +got a job at MIT. + +And he taught at MIT +from 1905 to 1912. + +And then in 1912 he was lured +to the West Coast where they + +were starting to establish the +chemistry department, the + +University of California at +Berkeley, and he went out to + +Berkeley and that's where he +spent the rest of his career. + +And we can speculate +why he went. + +Maybe he was fed up with +the weather here. + +Actually, today is one of those +few days-- write it + +down, because one of the few +lovely days in Massachusetts. + +So G.N. + +Lewis, what did he say? + +He said, well I've +got an idea here. + +He said, what if hydrogen +achieved shell filling not by + +electron transfer but +by electron sharing. + +So he posited the idea of shell + +filling by electron sharing. + +This is in contrast to +electron transfer. + +So let's see. + +Oh. + +There's an image of G.N. + +Lewis. + +He died, actually, on the job. + +He came back to his +lab one day after + +lunch and hit the floor. + +So he worked right +to the very end. + +Here's some data taken +from a lab + +notebook and memo, actually. + +1902. + +And what do you see here? + +Well, he developed a notation +for us, and we still use this + +notation to this day: +Lewis notation. + +So here's lithium and he's +got one electron. + +But we know lithium has +three electrons but + +only one valence electron. + +And then there's beryllium +and magnesium-- + +two electrons. + +Aluminum with three. + +Here's fluorine chlorine, and +when they ionize he puts the + +eighth electron right here. + +And look at this one +for silicon. + +He's got probably some kernel +inside the atom, thus. + +So he's even starting to think +about concentric shells. + +This is 1902. + +Remember the Bohr model +isn't until 1913. + +So you can see people +struggling. + +And notice that we have eight +electrons in a shell-- + +that's where we're getting +the octet stability-- + +and he's using cubes. + +Now we know that the cube isn't +the shape of the shell, + +but it's a pretty good device +to help you keep track of + +electron number-- + +because there's eight +corners on a cube. + +So it's another example of how +that's not what it is but it's + +a really good model and it keeps +you out of trouble and + +allows you to go forward. + +So this is going back-- way, +way back-- for G.N. + +Lewis. + +Now let's use this idea +and account for the + +formation of H2. + +So here's hydrogen, and using +the Lewis notation we'll put a + +dot here for its one electron. + +And we'll bring in a second +hydrogen and we'll use a + +cross, or an x, to indicate +the electron + +from the second hydrogen. + +And now we're going +to double count-- + +in other words, double +attribute. + +These are shared electrons so +they count for both atoms. + +Double count the shared +electrons. + +And when you do so what +do you come up with? + +Well, the element on the left +has two electrons and, + +therefore, is isoelectronic +with helium. + +OK? + +Maybe it was a California +thing. + +They were sharing. + +And then there was +sort of another + +California concept, like. + +So it was like helium. + +And then on this side this +is also sharing. + +And it's kind of like helium. + +So now we've achieved the +stability of the filled shell + +by sharing the electrons. + +OK. + +And I think I even have +another slide of how-- + +this is the more modern +version of it. + +Electron dot. + +So the nucleus and the +inner-electrons are contained + +inside the chemical symbol. + +And, actually, this goes +all the way to + +modern quantum mechanics. + +Density functional theory does +the same thing: lumps all of + +the inner-shell electrons plus +the nucleus into one piece, + +and then the valence electrons +are outside. + +And so starting in 1902 with +some little dots and crosses + +we go all the way +to DFT today. + +All right. + +So let's do another one. + +How about nitrogen? + +Let's try nitrogen. + +So when we going to nitrogen +we know the valence + +electron's 2s2 2p3. + +So put nitrogen here. + +One, two, three, four, five. + +Now these three electrons +here are + +according to the Hund rule. + +So it's px, py, pz, and this is +the 2s2 sitting over here. + +And I'll bring in a second +nitrogen, and there's its 2s2. + +2px, 2py, 2pz. + +And now what do I have? + +Look at the nitrogen +on the left. + +Two, four, six, eight. + +So the nitrogen on the left +feels as though it has access + +to eight electrons. + +The nitrogen on the right-- +two, four, six, eight-- it + +feels as though it has access +to eight electrons. + +So both nitrogens are +isoelectronic with neon if we + +push on this concept of +electron sharing. + +Now there's a second +thing I want to do. + +It's to draw attention to +two types of orbitals. + +So these three orbitals in the +center consist of electrons + +that are shared. + +So these are going to be called +bonding orbitals. + +And "bonding" and "blue" both +begin with a "b", so I'm going + +to denote the bonding orbitals, +or bonding domains, + +as distinct from the nonbonding +domains in red. + +Red are nonbonding domains. + +Always two electrons +per orbital. + +They like to live in pairs. + +That's the way it works. + +OK? + +And so each one of these +pairs is a bond. + +So I can then write nitrogen +with three lines through it + +indicating I have +a triple bond. + +Three pairs of electrons, +three bonding + +domains, triple bond. + +This is all in formation +according to the concept of + +electron sharing. + +And Lewis coined a name for +the type of bond that is + +formed in this way. + +He said we get bond formation +involves cooperative use-- + +sharing, cooperative-- + +of valence electrons. + +So now we can take the "co" +symbol here and the "valence" + +here and come up with the term +"covalent bond." Covalent + +bond, thanks to G.N. + +Lewis. + +So, again, to make sure we're +very clear, ionic bond results + +from electron transfer, covalent +bond results from + +electron sharing. + +Now we can do this-- so let's go +to heteronuclear molecules. + +These are homonuclear. + +So let's go to heteronuclear +molecules. + +And so let's see. + +I've got some rules +up here, I think. + +Yeah. + +Drawing Lewis structures. + +So let's go to a heteronuclear +molecule. + +And I'm going to choose as an +example sulfuryl chloride. + +And I don't expect you +to be able to name + +these things on site. + +I will always give +you the name. + +I'll say sulfuryl chloride, +parenthesis, SO2Cl2, blah, + +blah, blah. + +OK? + +So sulfuryl chloride. + +I want to put up the Lewis + +structure of sulfuryl chloride. + +So center the element with the +lowest average valence + +electron energy. + +So it turns out that the average +valence electron + +energy stack like this. + +Sulfur is the lowest, then +chlorine, and then oxygen. + +This is this ranking of average + +valence electron energies. + +And you'd be given those data. + +So it says put sulfur +in the center. + +So I'll put sulfur +in the center. + +And then what does it say? + +We're going to count all +the valence electrons. + +So sulfur over here +is 3s2 3p4. + +So that gives me six +valence electrons. + +And there's two oxygens. + +And oxygen lies above sulfur, +so that's 2s2 2p4. + +So that's 2 times 6. + +So that's 12. + +All right? + +Let's put the 6 over here. + +And then there's chlorines +in this compound, + +so that's 3s2 3p5. + +So that's 5 plus 2 is +7, 2 times 7 is 14. + +And we add this whole +thing up, we get + +there's 32 valence electrons. + +And draw a single bond from each +surrounding atom to the + +central atom. + +All right. + +Again, this is a model. + +I'm not saying that this is the +shape of the molecule, but + +it's a way to count. + +All I'm doing is trying +to keep track of + +bonds and paired electrons. + +So I can put chlorine +on either side. + +And I'll put an oxygen below +and an oxygen above. + +All right. + +So that's already two, +four, six, eight. + +So I'm losing eight. + +So 32 minus 8 is 24. + +And so with the 24 that means +I've got 12 pairs of + +electrons to place. + +So let's start putting the +Lewis structures up. + +So chlorine consists +of one, two, three, + +four, five, six, seven. + +And I'll do the same thing +on the other side. + +Two, four, six, seven. + +And oxygen has six, so that's +two, four, six. + +And then the lower +one, same thing. + +Two, four, six. + +And sulfur has six. + +I'm going to use +x's for sulfur. + +So I'll put one x with +the chlorine, + +another x with the chlorine. + +Two with the oxygen, two +with the oxygen. + +And so now we're in pretty +good shape, right? + +We can identify bonding and +nonbonding domains. + +Here's the bonding. + +One, two, three, four. + +And then the nonbonding. + +Looks like there's 12. + +And sure enough, 1, 2, 3, 4, +5, 6, 7, 8, 9, 10, 11, 12. + +The 12 nonbonding domains. + +4 bonds. + +And we have the Lewis +structure for + +this particular compound. + +And one last little piece +worth pointing out. + +Notice that in the bonds to +the chlorine you have two + +electrons, as you need. + +One electron comes from the +chlorine and one electron + +comes from sulfur. + +But in the bonds between the +sulfur and the oxygen the + +sulfur's so desperate to form +a bond that it actually + +donates both electrons +to the bond. + +And oxygen's happy because it's +isoelectronic with neon, + +and sulfur's happy because it's +going to be isoelectronic + +with argon. + +But, you know, it has to +go to some lengths. + +So this is called a dative bond, +when both electrons come + +from the one element. + +OK. + +Well, this is great. + +I'm going to do one more. + +How about methane? + +CH4. + +So I'm going to start +with carbon. + +Carbon's going to go +with this on there. + +And a carbon is 2s2 2p2. + +And so I'm going to use +the box notation now. + +See, this is the Lewis +structure, this is chemical + +equation, now we're going +to a box structure. + +We can move fluidly from +one model to another. + +We had cubes up there. + +It's all good. + +So this is 2s. + +And now this is 2px, +2py, and 2pz. + +Now according to this, +2s2, that gives + +me an electron pair. + +And now I've got 2p2, which +according to the Hund rule + +goes in like this. + +Well I've got a problem here. + +How many unpaired electrons? + +Two. + +Now what's my maximum number +of bonds I can form by + +electron sharing? + +It's two according to this. + +So the best I can do, best +possible here, is CH2. + +And that's no good. + +We know from mass measurements +it's CH4. + +The stoichiometry's CH4. + +And besides, what are these +orbitals going to look like? + +These are the p orbitals, so +they're dumbbell-shaped and + +they're orthogonal, right? + +They're 90 degrees, which means +if I formed this thing-- + +which is called methylene-- + +if I form methylene I'd end up +with CH2 looking like this, + +which has a dipole moment. + +And we know from spectral +measurements and electrical + +properties measurements that +this thing is symmetric. + +So this thing-- + +electron sharing +isn't working. + +It's not working. + +So we need another patch here, +and that patch comes from none + +other than Linus Pauling. + +Another American. + +You see, it's American science +today and it's in the 20s. + +That's why we have Gershwin +playing at the beginning. + +Celebration of American +science. + +So Pauling was born in +Portland, Oregon. + +He was the son of a pharmacist. +And he went to + +Caltech, got his PhD in 1925. + +So the Rhapsody in Blue came out +in 1924 when he was just + +hunkering down to his thesis. + +Probably listened to it, got +some pleasure out of it, as + +most people did. + +So then he finishes, 1925, at +Caltech in Pasadena and he + +goes to Europe. + +Now he chose wisely. + +He chose four postdoctoral +positions. + +These are people he +postdoc'd with. + +First with Sommerfeld, then +with Bohr, then with + +Schrodinger, and then +finally with Bragg. + +You'll learn about Bragg. + +Bragg got the Nobel Prize +for X-ray diffraction. + +So that's not a bad +preparatory start. + +So he comes back and +teaches at Caltech. + +In fact, I have a picture +of Linus Pauling. + +There he is. + +That's a middle-aged Linus +Pauling, probably around the + +time he got the first +of two Nobel Prizes. + +So what did Pauling do? + +Pauling said, why don't +we mix the orbitals? + +They're all in the shell n +equals 2, and what we're + +trying to do is to fill +the n equals 2 shell. + +So how about mix? + +Let's mix 2s and 2p states +in order to maximize + +the number of bonds. + +Remember, when you form a +bond you decrease the + +energy of the system. + +Four bonds is a greater +decrease in + +energy than two bonds. + +So the system, if it could-- + +and they're all within +the same shell. + +You notice he didn't say, gee, +if mixing 2s with 2p is good + +let's go get some 1s. + +Well 1s is down in n equals +1, and there's + +no way you can mix. + +They had to be in +the same shell. + +Mix states in order to +maximize number of + +bonds that can form. + +It's all about maximize +the number of + +bonds that can be formed. + +And this, of course, is +by electron sharing. + +We're talking about covalent +bonds here. + +OK? + +And he termed these mixed +orbitals "hybrids." Termed the + +mixed orbitals as "hybrid +orbitals." They're + +cross-breed-- + +part s, part p. + +So now let's look at the +energy level diagram-- + +or the box notation. + +Forgive me. + +So I'm going to mix s and p. + +So I've got a single s and I've +got three p's, so this is + +called sp3. + +Each one of these is a mixed +sp3 hybrid orbital. + +And I've got four of them. + +And how many electrons +do I have? + +Four. + +So now I use the Hund rule +and in go the electrons. + +One, two, three, four. + +And now I have the ability +to form four bonds. + +But it gets better. + +Here's the next thing. + +These are degenerate. + +They're all in the same state. + +That's why we're using +the Hund rule. + +And so degeneracy in energy +implies degeneracy in spatial + +orientation. + +So what does that mean? + +It means that if these are four +bonds equivalent, then + +the way those bonds will arrange +themselves in space is + +to be equivalent. + +So if I've got a central carbon +here and I'm going to + +put four sticks from the central +carbon so as to make + +the four sticks symmetrically +disposed in space, that + +dictates the architecture +of the molecule. + +And how do I put four sticks +off of a central point + +symmetrically disposed +in space? + +One, two, three, and four. + +This is meant to be the corners +of a tetrahedron. + +Each one of these is +109 degrees apart. + +And this describes +a tetrahedron. + +So now I've got carbon in the +center, and now I've got the + +hydrogens at the four corners +of a tetrahedron. + +There is the structure +of methane. + +And each of the hydrogens has +a shared electron with the + +carbon, making it isoelectronic +with helium. + +And the carbon has four of its +own electrons, four shared + +with the four hydrogens +to make it + +isoelectronic with neon. + +So everybody's happy. + +Shell filling, and +it's all good. + +So now it's symmetric and it +has no net dipole moment. + +Everything squares +with the data. + +Well, good for Pauling. + +But he went further. + +He went much further. + +What Pauling wanted to do was +to make it quantitative. + +And so he wanted to have +something analogous in + +covalent bonding to what we +have in ionic bonding. + +So what Leslie is now rubbing +off the board there is-- + +no, keep going. + +It's good. + +It's OK. + +This is a rule of academics: +You always erase that which + +you will refer back to. + +We need more boards in here. + +How many boards do I +fill in a period? + +9, 18? + +Maybe what? + +We need about 24 boards. + +That's a good lecture. + +All right. + +So here's what Pauling +was thinking about. + +He was thinking about the +analogy, for example, if I + +want to get the energy of +magnesium oxide I can use the + +formula that Leslie has +just erased, and + +it looks like this. + +So if all I need to know is the +radius of the anion, the + +radius of the cation, it's +charge, and the Madelung + +constant and then I just +plug in, I get the + +crystallization energy. + +But then suppose instead of +magnesium oxide I want to go + +to magnesium chloride. + +I can use the same formula +only I need + +the Madelung constant. + +This is the Madelung constant +for magnesium oxide. + +If I have the Madelung +constant-- + +forgive me, script M-- + +for magnesium chloride, and +I know the ionic radius of + +magnesium cation and chloride +anion, away I go again. + +I need this. + +I need, of course, the +Born exponent. + +This Born exponent +and away we go. + +The same formula applies. + +So I can build with a library +of basic physical data. + +So what did Pauling do? + +Pauling said, what if we +can do the same thing + +for covalent bonds? + +Is there some kind +of an analogy? + +So he said, let's take a +look at an arbitrary + +heteronuclear compound. + +So I'm going to do this with +HF, hydrogen fluoride. + +So, first of all, let's build a +hydrogen fluoride molecule. + +H with its one electron, and +fluorine with its seven. + +So now hydrogen sharing an +electron with fluorine is + +isoelectronic with helium. + +It's happy. + +And fluorine sharing the +electron hydrogen is + +isoelectronic with neon. + +It's happy. + +So again we see shell filling +by electron sharing. + +So what Pauling wanted to ask +is, can I get a measure of the + +HF bond energy knowing +only the bond + +energies of H-H and F-F? + +So then if I knew all the +homonuclear bond energies and + +then I mixed these to make +heteronuclear bonds, is there + +a path from homonuclear +bond energy to + +heteronuclear bond energy? + +So let's look and see what +the numbers are. + +So hydrogen. + +The hydrogen bond's +fairly strong. + +It's 435 kilojoules per mole. + +That's mole of bonds. + +435. + +Fluorine-flourine is 160. + +And so what do you think +the value of the + +H-F bond should be? + +Well when I first look at this +I say, well it's part H and + +it's part F, so it's somewhere +between 435 and 160. + +I don't know if it's the +arithmetic mean-- + +you know, add these two and +divide by two-- or maybe it's + +the geometric mean-- + +multiply them together and +take the square root-- + +but it's got to be somewhere +in between. + +What do the data show? + +The number's 569, which +is greater than 435. + +So I take a bond of 435 and +a bond of 160, I put them + +together I get 569. + +That's very, very strange. + +But Pauling was smart. + +Pauling said, I have +an explanation. + +He says, suppose when these +electrons are shared in + +between the two atoms, suppose +they're not shared equally. + +Suppose there is a displacement +of the electrons. + +So instead of putting them +dead center, as I've been + +doing up until now, suppose +the electrons are actually + +drawn closer to the fluorine. + +So we still have octet +stability, or in this case + +duet stability, but +the sharing of the + +electrons is not equal. + +So this is charge +displacement. + +And what does charge +displacement constitute? + +Well, charge displacement +means stored energy. + +And Pauling quantified +that stored energy. + +And so what he did is he said +that you increase the bond + +strength by thinking of it +as a two-step reaction. + +So in the heteronuclear bond +that is a bond between two + +different atoms. So in a +heteronuclear bond we form by + +what-- and this is my coinage, +you don't see this + +anywhere in the book-- + +two-step, share and then pull. + +So share is, as the name +implies, we share electrons to + +achieve octet stability. + +But then because we have unequal +atoms we pull towards + +one of the atoms. And which +one do we pull towards? + +Well, we pull towards the one +that's got a greater appetite + +for electrons. + +And we've already gone +through this concept. + +Which atoms on the periodic +table have the highest + +appetite for electrons? + +The nonmetals. + +The weakest appetite +is the metals. + +The metals are good donors, the + +nonmetals are good acceptors. + +And fluorine's up in the top +right corner, so fluorine has + +a very, very high appetite +for electrons. + +And, indeed, in this bond +the electrons are + +pulled to the right. + +And why Pauling got the Nobel +Prize and Lewis didn't-- it's + +my theory-- is that Pauling +was quantitative. + +So he came up with a +quantitative measure. + +He devised a quantitative +measure for the degree of + +unequal sharing, thereby +allowing us to make these + +calculations with +some accuracy. + +And he called that quantity +electronegativity, and it's + +denoted by the Greek +symbol chi. + +OK? + +And he devised a whole scale. + +How did he get the scale? + +He looked at bond energies for +all sorts of pairs of elements + +across the periodic table and +went through an exercise with + +pencil and paper that today we +would call multivariable + +regression analysis. + +And came with a set of-- + +[SLIDE APPEARING] + +PROFESSOR: Oh, I'll +come back to this. + +This is the structure +of methane. + +This is the s and p. + +Oh, let's take a break. + +You can stack. + +All right. + +So this is what methane +looks like. + +There's the s, there's the p. + +And the sp hybrid +looks like this. + +It's sort of an asymmetric +dumbbell. + +And these four things +stick out. + +And then you bond the hydrogens + +and there's the methane. + +OK. + +So here's what the + +electronegativity scale looks like. + +It looks a lot like the +scale for average + +valence electron energies. + +The nonmetals have the highest +appetite for electrons period, + +which means in a bond they're +going to hog the electrons. + +And the nonmetals have the +weakest appetite, and so + +they're going to end up having +the electrons in a covalent + +bond pulled away from them. + +So nonmetals have high +electronegativity, metals have + +low electronegativity. + +And now here's taken +from the text. + +And you see that the +electronegativity is periodic. + +If you go across a period the +metal has the lowest value and + +the nonmetal has the highest. +And there's fluorine, number + +nine, at a value of about 4. + +It's got the most intense +appetite for electrons. + +And then you jump down here to +sodium, et cetera, et cetera. + +Here we are going across the +lanthanides and whatnot. + +And this is taken +from your text. + +There's fluorine, 3.984. + +That's the thing. + +And down here we have very low +values of electronegativity. + +So with electronegativity +we are now able to make + +calculations. + +And this is the Pauling formula +for calculating the + +bond energy in a heteronuclear +bond starting from homonuclear + +bond energy. + +So let's continue with the HF. + +So if I want to get the +bond energy of HF + +I'm going to take-- + +and this is the Pauling +formula-- + +the geometric mean. + +So I take the bond energy of +hydrogen-hydrogen times the + +bond energy of + +fluorine-fluorine, and square root. + +So that's the geometric +mean of the two. + +And then comes the Pauling +piece that gets + +him the Nobel Prize. + +You take the difference in the +electronegativity between the + +two elements squared, and then +the factor 96.3 gives us the + +unit consistency with +kilojoules per mole. + +So the greater the difference +in electronegativity the + +greater the contribution here in +terms of the deviation from + +just the geometric mean of the +two homonuclear bond energies. + +Or put another way, if you have +a homonuclear atom such + +as H2, if it's chi H minus chi +H is 0, so this second + +term goes to 0. + +And obviously when fluorine is +one of the members you're + +going to get a very, very +high number, because + +this has the most-- + +and it doesn't matter which +order you put them in because + +you're taking the square, +so it's always + +going to come out positive. + +And I want you to appreciate the +sense of scale here, so if + +we go in here we'll multiply. + +This is going to be +435 times 160. + +And I'm going to take the +square root of this. + +And then this is 96.3. + +And you look on your +periodic table + +this is 2.2 for hydrogen. + +Fluorine is 3.98. + +And I know there are different +tables of electronegativity. + +I don't care. + +Just whatever you've got +on your periodic table. + +The one in the book is a little +bit different but it + +all comes out in the wash. + +So you multiply all this out, +and we find that the first + +term is 264 kilojoules +per mole and the + +second term is 344. + +So this second term is even +greater than the first term. + +So the amount of energy in that +electron displacement is + +substantial. + +And if you sum the two +of these you get 608. + +Now you might say, well +wait a minute. + +The real number is 569. + +But 608 takes you in the right +direction and accounts for the + +contribution of electron +displacement. + +264 is just plain wrong. + +So this was an important +start for Pauling. + +And he has labels on these +two contributions. + +This first term, which is just +the combination of the + +homonuclear bond energies, is +called purely covalent. + +It's the purely covalent +contribution. + +And it's what I've been +referring to as the sharing. + +This is what you get +from sharing. + +OK? + +And then this second term here +with the difference in + +electronegativity is what you +get from what I've been + +calling the pull on +the electron pair. + +And Pauling called this the +partial ionic character. + +He's not saying that there's +electron transfer, but it's a + +move in that direction. + +Partial electronic character. + +So what I've done here is I've +decided I'll make a sort of a + +panorama of what we've +seen up until now. + +And so I'm going to make +something called the electron + +sharing meter. + +All right. + +So if I look at a homonuclear +system like hydrogen. + +So my meter reads neutral. + +So the arrow's at 12 o'clock. + +The electrons are +shared equally. + +And then if I go to +HF what do I have? + +Well, I know that the fluorine +is pulling the electrons. + +And so we can designate that by +writing delta minus, delta + +plus. delta the physicists +use. + +The lowercase Greek delta +means little bit of. + +All right? + +So delta minus means it's +a little bit negative. + +And we've got charge neutrality, +so if the fluorine + +end is a little bit negative +then the hydrogen end has to + +be a little bit positive, which +means this thing has a + +net dipole moment. + +It's a dipole. + +And the arrow points to +the negative end. + +One way to think about it is I +put a little slash there and + +that starts to look a little +bit like a plus sign. + +You can come up with your +own way to remember it. + +So it's got a little bit +of a dipole moment. + +And people depict dipoles +usually as ovals, and they'll + +put a minus end and +a plus end. + +So it's net neutral but the +charge is not uniformly + +distributed. + +OK? + +So our sharing meter in this +case is going to show + +something to the right. + +We've got electrons that are +unequally shared, and that + +moves over to the right. + +And, you know, the dipoles have +interesting properties. + +Oh, there's a plot of +electronegativity + +3-bar in the bar plot. + +And actually this is +an interesting one. + +Just parenthetically, you +see hydrogen here? + +Hydrogen's weird. + +They put it in the periodic +table above lithium but it's + +not an alkaline metal. + +And you can see it just +doesn't belong there. + +And there's a lot of +conversation about putting it + +maybe somewhere centered above +the p block elements, because + +it certainly doesn't belong +next to helium. + +But it probably doesn't belong +above lithium either. + +Anyway, I thought that +was very interesting. + +I can tell from the +response of the + +class, why does he care? + +[LAUGHTER] + +PROFESSOR: All right. + +Now this is really-- + +I'm going to use an +adverb here-- + +this is really important. + +All right? + +So here's HCl, is a cousin of +HF, and you see in the upper + +frame it's just a bunch of HCl +molecules just bopping around + +any which way. + +So there's the delta plus +and the delta minus. + +Now if you take these dipoles +and you put them in an + +electric field they will align +themselves, and the positive + +ends will face the negative +plate and the negative ends + +will face the positive plate. + +And there's energy stored when +the random orientation goes + +into an ordered orientation. + +This is the principle +behind a capacitor. + +A capacitor is nothing +more than a whole + +bunch of aligned dipoles. + +So if you want to invent a +supercapacitor that we can use + +on a car to extend the range +of the automobile so we can + +reduce our dependence on +imported petroleum, you're + +going to look for molecules +that have a + +honking big dipole moment. + +That way you get more energy +per unit electric field. + +So, again, a simple idea that +tells me how to go and invent. + +I can go back to my office and +go and invent something right + +now just based on +this lecture 9. + +[LAUGHTER] + +PROFESSOR: See, you +go and invent. + +You start the company, +you make the billion. + +Remember good old Professor +Sadoway at MIT, and + +established the fellowship +for students, and so. + +All right. + +But you have to know what +a dipole moment is. + +Got to know what a +dipole moment is. + +OK. + +So there's the dipole moment. + +And then lastly I'm going +to put sodium chloride. + +So what's sodium chloride +look like? + +Well it's Na plus +and Cl minus. + +So the electron has transferred +completely. + +So this isn't even +sharing at all. + +So this is really +bury the needle. + +This is not sharing. + +In this instance the sodium +doesn't even get visitation + +rights to the electron. + +The electron's gone. + +Whereas here hydrogen gets to +see the electron on Saturdays + +kind of thing. + +Depends what kind of lawyer +fluorine had. + +That's what it all +boils down to. + +All right. + +This is the same thing that +I just showed you. + +But you see, the textbook +gives you, as the name + +implies, dense text. + +I gave you the sharing meter. + +The sharing meter is far +more expositive. + +All right. + +And then, finally, the percent +ionic character is given by + +this formula here. + +So this is 1 minus +the exponential. + +So the exp term, this +exponential of-- what is it-- + +minus 1/4 times the +difference in + +electronegativities squared. + +This notation means e base +natural logarithms, minus 1/4, + +blah, blah, blah. + +That's what this thing is. + +So if you plug in, multiply by +100% you get something that + +goes from 0 to 100. + +So obviously when delta +chi is 0 you get 0%. + +e to the 0 is 1, 1 minus +1 is 0, and so you + +have no ionic character. + +And so if you plug in +the numbers for HF-- + +so you're going to take this +difference here, square it-- + +it ends up giving you 1.8, which +gives you a value of + +about 56% ionic character. + +So it's as though the electron +is sort of half transferred. + +But you might also look at +it from this perspective. + +If you take 344-- + +because this is the partial +ionic character, which is the + +energy of electron displacement +over the total + +energy in the calculation-- + +that turns out to be 57%. + +So this stuff makes sense. + +There's a sensible metric +here at work. + +And so this is what Linus +Pauling got his Nobel Prize + +for, and it's the description +of polar covalency. + +And polar covalency is operative +when you have + +heteronuclear bonds, because +the two different elements + +don't share the electron +equally. + +And the Pauling formula allows +you to calculate that. + +And his formative book was +written in 1937, called The + +Nature of the Chemical Bond. + +OK. + +So turning to the last five +minutes, I want to bring to + +your attention some covalent +molecules. + +Today we're going to +talk about Freon. + +Freon was an invention, it was +a designer chemical, invented + +by Thomas Midgley. + +This is me. + +I named him "sp3." That's +his nickname. + +Thomas sp3, for the hybridized +orbital. + +So he was working at the +Dayton engineering + +laboratories in Dayton, which +was owned by General Motors, + +and he was working in the 20s +at a time when there were no + +refrigerators in American +kitchens. + +The only refrigerants that were +used were either toxic or + +flammable, things like ammonia, +methyl chloride, + +sulfur dioxide. + +And you read about horrible +accidents. + +People making ice cream at some +plant and the compressor + +blows up and two or three +people are killed. + +So it was deemed unsafe in +the American kitchen. + +In the 20s Midgley discovered +this molecule, which looks + +just like methane only we've +replace the hydrogens with two + +chlorines and two fluorines. + +So this is called +dichlorodifluoromethane and + +it's a chlorofluorocarbon, +a CFC. + +And this was fantastic stuff. + +It it was colorless, odorless, +tasteless, non-toxic. + +It was not just used as a +refrigerant, it was used in + +propellant. + +When I was your age all +of the sprays-- + +whether it was hair spray, +shaving cream, any aerosol-- + +was propelled by Freon-12. + +It was fantastic stuff. + +Well, it turns out that in +the upper atmosphere-- + +you know, you go pss pss pss. + +You got people all over the +world doing this, eventually + +this stuff starts +floating away. + +And what turns out in the upper +atmosphere where we + +don't have shielding +from ultraviolet-- + +you know how to do this +calculation, because you can + +look up the energy. + +And, in fact, it's part of your +homework, where you look + +at the energy differences and +the electronegativity + +differences, you can compute the +wavelength of light that's + +capable of breaking the +carbon-chlorine bond. + +And it turns out to be +in the ultraviolet. + +Once the chlorine is broken you +have a chlorine radical, + +and that chlorine radical goes +over here and attacks ozone. + +[CELL PHONE RINGING] + +PROFESSOR: Cell phone-- + +out. + +Just get up and leave +out of courtesy. + +[CELL PHONE STILL RINGING] + +[LAUGHTER] + +PROFESSOR: Hello? + +The first year I was teaching +3.091 there was a Nobel Prize + +awarded to Mario Molina, who was +a faculty member here in + +Earth and Planetary Sciences who +had worked years earlier + +at University of California, +Irvine, and had speculated on + +the mechanism by which ozone +depletion occurs and linked it + +to rising levels of CFCs. + +Initially-- + +that's why it says +a vindication-- + +people pooh poohed it, +said it was crazy. + +There wasn't enough of this pss +pss to cause any trouble. + +But then later with the NASA +program they started taking a + +lot of images and they could +track ozone levels in the + +atmosphere and start seeing +that not only was ozone + +changing but there were actually +pockets where ozone + +was being depleted at an +accelerating rate-- because + +obviously the atmosphere isn't +constant composition and + +constant temperature. + +Duh. + +So anyways, yeah. + +There he is. + +And this was the paper that was + +published in 1974 in Nature. + +And this was done before +computers. + +The PC wasn't invented +and commercialized + +until the early 80s. + +So this was typeset, and the +person who typeset it + +obviously didn't take 3.091 +because instead of "atom" + +hyphen "catalysed" we have +"atomc-atalysed." But even + +ignoring the spelling error in +a Nobel Prize winning paper-- + +[LAUGHTER] + +PROFESSOR: --the Nobel committee +overlooked this. + +Yeah. + +So there it is. + +And then they went to +HFCs and so on. + +There's a lot of activity +in this. + +And what happened is when we +changed from CFCs to HFCs we + +had to change the design +of the compressors. + +And what happened was +everything got + +much, much more efficient. + +So this was an example of +necessity for a change that + +was driven by concern +for the environment. + +Instead of putting people out +of work and killing an + +industry, gave us much more +efficient refrigeration. + +And the last thing I'll +show you is this + +to draw your attention. + +This was in your textbook. + +This is the cap at the top of +the Washington Monument. + +The Washington Monument was +built to celebrate the + +American centennial, 1876. + +They finished it in 1884. + +And this is 100 ounces of +aluminum, because aluminum was + +a precious metal. + +It was priced higher +than silver. + +1884. + +Two years later Charles Martin +Hall and Paul Heroult invent + +an electrochemical process +that drives the price of + +aluminum down to the point +that we make beer cans-- + +I mean soda cans-- +out of it today. + +[LAUGHTER] + +PROFESSOR: And a good example of +how chemical innovation can + +lead to superior products. + +I'll see you on Wednesday. \ No newline at end of file diff --git a/usWjdV0-Jg0.txt b/usWjdV0-Jg0.txt new file mode 100644 index 0000000000000000000000000000000000000000..f77b6fedf07553d02870d140ae9c00b628971550 --- /dev/null +++ b/usWjdV0-Jg0.txt @@ -0,0 +1,3870 @@ +PROFESSOR: Today we begin the +third major part of the class. + +We've done paper +folding, linkage folding, + +and now we're going to +do polyhedron folding. + +The very last topic we +did was hinged dissection, + +which is somewhere in the +middle of all these things. + +But with polyhedron +folding, we're + +thinking about a two +dimensional surface + +in 3D, something like +a cube, and we're + +interested in cutting along +the edges of that shape + +or somehow cutting along +the surface-- that's + +a good cutting-- and then +unfolding into some flat shape. + +So this is a standard cross +unfolding of the cube. + +This is the unfolding process, +and of course the reverse + +is the folding process, and +both of them are interesting. + +We're going to start +thinking about unfolding. + +That's one of the most +practical problems here. + +You really want to build some +3D shape out of sheet material. + +What shape do you +cut out in order + +to bend it into that surface? + +So you start with the surface. + +You need to figure out where +to cut so that when you unfold, + +you get something +that has no overlap. + +If you want to make +it from one sheet, + +it shouldn't have any overlap, +and ideally just one piece + +because then you have to do +less welding or edge joining + +to make that surface. + +So today and the +next couple lectures + +will be all about unfolding, +and then eventually we + +will turn to the reverse +problem, folding problem. + +And there are two +kinds of unfolding. + +The one that I just +drew is an edge + +unfolding because it +only cuts along edges. + +Edge unfolding only cut +along edges of the surface. + +This property is nice. + +If you're building +something, you + +don't want to have +visible seems. + +You have to be +bent at the edges, + +so it's not such a big +deal if you're also + +fusing along an edge. + +But in general, you could +imagine cutting anywhere + +on the surface, and +this is an example + +where the solid red +lines are cutting + +on what you see and the +dotted red lines were + +cutting on the backside. + +And when you unfold that thing, +you get this stoplight polygon, + +and this is what we call a +general unfolding, or just + +unfolding. + +There you can cut anywhere. + +In both cases, we want +one piece, no overlap, + +but you can change where +you're allowed to cut. + +So those are the +rules of the game, + +or two possible +rules of the game. + +And let me tell you what's +known about these kinds + +of unfoldings. + +I've mentioned it way +back in lecture one. + +so we can think +about edge unfolding, + +we can think about +general unfolding, + +and we can think about +them for convex polyhedra-- + +simple things like the +cube have no dents-- + +or general polyhedra, +non-convex polyhedra. + +And status is these +two corners are open. + +This one is solved. + +It can always be done. + +You can always generally +unfold a convex polyhedron, + +but we don't know about +general polyhedra. + +Edge unfolding of +convex polyhedra, + +we don't know whether +it's possible, + +but for non-convex +polyhedra, we know + +that's too much to hope for. + +Not always possible. + +Both of these questions +could go either way, + +but we know in various +generalizations, easy case + +of convex polyhedra general +unfolding, we can do it. + +The most restrictive, +hardest situation + +is edge unfolding +non-convex polyhedra. + +That's too much. + +But each of these +things, we don't know. + +And these are some of the +biggest open questions + +remaining in geometric folding +algorithms, this field. + +I'm going to talk mostly +about these three things + +today, so this open problem +and these two results. + +And then this topic will +essentially be next lecture. + +Obviously it's not solved, but +we still have a lot to say. + +There are various +partial results + +toward solving both +of those problems, + +I would say more on this one. + +This one is five centuries old. + +This one is one +decade old or so. + +So I need to set the stage +a little bit before I + +can talk about any +of these things, + +so let me start with a +little bit of terminology. + +We've in some sense talked +about curvature before. + +I don't think I gave +it this name, though, + +in the context of origami. + +And I use it almost +subconsciously + +so it's good for +me to define it. + +If you have some vertex +on your polyhedron. + +Let's say we're looking +at a corner of a cube, + +so this has three 90 degree +angles coming together. + +You sum those +angles, we get 270, + +and then you take +360 minus that sum, + +and that is your curvature. + +This is going to be 90. + +And what I really care about +is whether the curvature + +is positive, 0, or negative. + +Positive curvature, which +is what we got here-- + +this is plus 90-- is +like a convex cone. + +So if you're thinking about +convex polyhedra, which + +is one of the situations +we care about, + +you'll always get positive or +0, maybe, curvature vertices, + +depending on what +you're thinking about. + +Zero, this is like +a piece of paper, + +so this is what you might call +flat, but it's locally flat. + +It could be drawn +flat or we know + +how to fold pieces of paper. + +You never change the curvature. + +The sum of the +instant face angles + +will always stay the same, no +matter how you fold this thing. + +Curvature is an invariant. + +If you just think locally and +forget about the actual folding + +of the thing, it's kind of flat. + +So you can think of this +as a piece of paper. + +We talked about +these two situations + +in the context of Kawasaki's +theorem way back when. + +Kawasaki's theorem +applied for both + +of these for the negative +curvature case, which + +is when you have lots +of material all joined + +at a single point, +something like this. + +Then Kawasaki's theorem +changed a little bit. + +There were some other +cases that could happen. + +So when you have +tons of material, + +this can only happen in +a non-convex polyhedron. + +That's sort of the point. + +If you're a convex +polyhedron, you + +know you have to have +only these two situations. + +Where do you get flat vertices? + +Well, if you think of +this point as a vertex + +and you add up all the angles +around it, well, that's 360. + +360 minus 360 is 0. + +So you have zero curvature on +all the faces and on the edges. + +Also, if you look here, +you have 180 and other 180. + +That adds to 360. + +And then at the actual +vertices, that's + +where you have positive +curvature for a convex + +polyhedron. + +So just some terminology. + +Get used to the idea of positive +curvature, zero curvature, + +and negative curvature. + +Then we have the +idea of a cutting. + +So cutting is just, +what edges do you cut? + +It's the red stuff +in this picture. + +What edges do you cut +in order to unfold? + +So this is an unfolding, the +mapping here, but the red part, + +I'll call it cutting. + +Sometimes it's also +called an unfolding, + +but that can be a +little confusing. + +The main point here is I want +to talk about what constraints + +cutting must satisfy in order +to be valid so we can just + +get a sense of what +is happening here. + +If you look at these pictures, +you can see two properties. + +One is that the cuttings +visit all the vertices + +of the polyhedron. + +So there's this red stuff. + +The red stuff is connected. + +It's acyclic, so it's actually +a tree in these pictures, + +and it's visiting +all the corners. + +Even back here, it's +visited on the back. + +Is that always true? + +Most of those properties +are mostly true, + +but it depends a little bit. + +One thing that is +sure is the cutting + +must span all non-zero +curvature vertices. + +But I do have to say +"non-zero curvature." "Spans" + +just means visits. + +You have to hit all the +vertices of non-zero curvature + +because anything of +non-zero curvature + +can't be flattened by itself. + +It needs to be cut. + +At that point, the cutting has +to have degree at least one. + +With zero curvature +vertices, even if they're not + +flat in three dimensions, +you could flatten them + +because we know locally, +it really is a flat thing. + +So there may not be any cuts +at zero curvature vertices. + +Most of the time, we won't +have to worry about them, + +but something to think about. + +Everybody else you have to span. + +You can say even more. + +If you have very +negative curvature, + +if the curvature of a vertex +is less than some integer, + +k times 360 with a minus +sign in front, then cutting + +must have degree strictly +more than k plus 1. + +So if you have +negative curvature, + +you know you have to +have at least two cuts + +for a negative curvature +vertex because if you + +had negative curvature-- +one of these things-- + +you made a single cut. + +Then all that material +is still there. + +If you then flattened it, +it's going to overlap itself + +because you're trying +to flatten it into 360. + +There's more than +360 material there. + +So negative curvature already, +you need two vertices. + +That's the plus 1 here. + +And as soon as you get to +smaller than negative 360, + +then you have to have at least +three cuts and so on, just + +to partition up into +at most 360 groups. + +This is useful. + +Negative curvature is basically +really tough to unfold + +and we'll use that to make +counter examples here. + +What else? + +your polyhedron has no handles, +then cutting has no cycles. + +A handle is something +of higher genus. + +If this is your polyhedron, +we call this a handle. + +You have sort of +a blob down here + +and you have a connection +from one place to the other. + +If you have a +handle, you can have + +a cycle of cuts like this +that does not disconnect + +the surface, but we +basically never think + +about that situation. + +Whenever we're thinking of +something of genus zero, + +like a convex polyhedron or a +regular, non-convex polyhedron, + +you really shouldn't have +a cycle in your cutting + +because if you +had a cycle, you'd + +disconnect your +surface into two parts + +normally, if you're like +a sphere or like a disk. + +That's the acyclic +condition and when it holds. + +Some other good things. + +If a polyhedron has no +boundary and no handles, + +and the unfolding has +no holes, then cutting + +is a spanning tree. + +Spanning tree, it's a concept +we've used a few times. + +It's just a tree. + +In this case, it's got +to visit all the vertices + +of non-zero curvature and +it's a tree, so it's connected + +and it's acyclic. + +The main new thing here +is that it's connected. + +We've already said +that it should + +be acyclic with no +handles, we've already + +said that it should +span everybody, + +so it's sort of a +summary theorem, + +but we have a whole +bunch of conditions here. + +In particular, this will hold +if your polyhedron is convex. + +So for convex polyhedra, +you have a spanning tree, + +and that's what's going +on in this picture even + +for general unfoldings. + +That's the interesting case. + +Here, it's maybe more +obvious, here it's + +a little less obvious. + +And to sort of see what could go +wrong here, I have an example. + +This is a non-convex polyhedron. + +There's a whole +bunch of views of it + +up here, and in +particular this top view. + +What we're doing is slicing +along just those two + +edges and some other +stuff around the outside, + +but in particular, we +cut those two edges + +and there aren't any +other cuts around there. + +A polyhedron is set up so +that when you open it up, + +this works out. + +It's nice and flat. + +This is extremely rare. + +If you perturbed this +example, it wouldn't hold. + +But you can set things up +so that, in fact, what's + +happening is that the total +curvature-- this vertex has + +positive curvature, this has +negative, this has positive, + +and the sum of those +three curvatures is zero, + +and that's what +allows this to be flat + +because the total curvature +in that little region is zero, + +and that's when things +are allowed to be flat. + +So you can cut here and make +a separate collection of cuts + +on the outside, but +it's disconnected, + +so this is kind of weird. + +Most of the time, things +will be connected, + +and as long as your +unfolding has no holes-- + +and for an unfolding +to have holes, + +you'd have to have +this weird property + +that a bunch of curvatures sum +to zero like in that picture-- + +as long as you don't +have that, you're OK. + +Let's get to these theorems. + +Actually, one thing +related to this problem, + +general unfolding of +arbitrary polyhedra, + +is you can't be too +general what you + +mean by non-convex polyhedra. + +So we have this example. + +It's the simplest nasty +polyhedron there is this. + +It has one vertex at the +top there with a big dot + +that has negative curvature. + +There's more than 360 +degrees of material + +from all these triangles. + +And that's sort of +all that it has. + +This is the polyhedron. + +This is what we call +boundary of the polyhedron. + +So far, all the polyhedra +I've done haven't had that, + +and you may have +seen that I assumed + +that it wasn't there +for that last lemma. + +This polyhedron can't +be unfolded at all + +in one piece, no overlap. + +Why? + +Because it has one vertex. + +You could think of +these as vertices, + +but they're kind of flat. + +Everything's flat +except that one point. + +It has negative curvature. + +Negative curvature, +we said you have + +to have at least two +cuts coming in there. + +If you just made one cut, then +when you flatten this thing, + +it'll overlap itself locally. + +So there's got to be at least +two cuts coming in there. + +I don't think that +even matters much. + +I mean, there's at +least one, certainly. + +Where could those +guys go, those cuts? + +They have to wander +around the surface. + +If they just stop in +the middle of nowhere, + +then you're sort of doing +nothing because a cut that just + +stops in the middle +of a flat vertex, + +well, you might as well +not have done that cut, + +so you could erase it. + +So it's got to go somewhere. + +They could go to each other, in +which case you've made a cycle + +and then you've disconnected +your surface because this + +is like a disk, or they +could go to the boundary. + +And if they both +go to the boundary, + +again, you disconnect +your surface, two pieces. + +So this is kind of pathetic, +but you can't unfold this + +with one piece, no overlap. + +So when I say, in +this picture, and I + +say that it's open whether +non-convex polyhedra can + +be generally unfolded, I +mean non-convex polyhedra + +without boundary. + +I'll even give you +handles if you want. + +I'm not sure that +it matters too much, + +but boundary seems to +make a big difference. + +So what's wrong +is this polyhedron + +is kind of incomplete, +and as long + +as you close it up somehow +and don't have these boundary + +effects, then maybe you can +generally unfold everything. + +That's this question. + +That was a little bit on this. + +We'll come back to +it more next lecture. + +Next, I want to do this one, +general unfolding of convex + +polyhedra. + +This is really the most +positive news I could give you. + +All this unfolding stuff, +it's the one good result. + +We know several good results, +but in terms of that table, + +it's our only good result. + +And to do that, there's a bunch +of solutions to this problem. + +They all use the idea +of shortest paths. + +The shortest path is a +path that's shortest. + +So you have some surface, +you have some points. + +You do this all the +time when you're + +flying between two cities. + +You follow a shortest +path on a sphere. + +It's not straight +in three dimensions. + +It's the shortest thing subject +to lying on that surface, what + +is the shortest path you can do? + +So you're used to +it on a sphere. + +It's a little weirder +on a polyhedron, + +but it's just the same idea. + +Take all the possible paths you +could, find the shortest one. + +You fix the two +endpoints, x and y, + +and you get to optimize this. + +Whatever is shortest +is the right thing. + +I have some pictures of +what they look like here. + +So these are some +convex polyhedra. + +They're probably random +points on a sphere, + +take the convex hull. + +And then we pick some vertex, +or some point x in the corner + +there, and this is +computing the shortest paths + +from x to every other +vertex on the polyhedron. + +So they look very +straight in this case + +because the polyhedron +is almost a sphere. + +They look kind of like great +circular arcs on a sphere, + +but they're not quite. + +You can look carefully +at an edge here, + +this does bend a little bit. + +It's a bit subtle. + +It bends only a little bit +because the property you want + +is if you look at this +triangle and this triangle + +and you unfold +them-- so right now, + +they have some dihedral +angle between them, + +and if you open it out +so that they're flat, + +then this line +should be straight. + +Still the case that shortest +paths are straight lines, + +but only when you unfold. + +That's the idea. + +So if you look at all +the triangles are visited + +by a path, and you unfold them +to be a straight thing-- this + +is called developing, you +flatten it out-- then actually, + +the shortest path will +be a straight line, + +so that makes it really +easy to draw these things. + +There still might be multiple +candidates, like to get here, + +should I go this way or +the other way around, + +but each of those will +be locally straight, + +and this is a property +called geodesic. + +Shortest paths always +unfold straight. + +And in general, anything +that unfolds straight, + +it might not even be +shortest, is a geodesic. + +These are like locally shortest. + +Locally, you can't +make them any shorter, + +but they might have +made the wrong choice. + +They might have gone +around the wrong way. + +Geodesic means going +straight for a long time. + +You could actually +spiral around and do + +all sorts of crazy things. + +But shortest paths +never cross themselves + +because if you had the shortest +path that crossed itself, + +that wasn't shortest. + +You should have just +gotten rid of this part + +and gone straight +through the crossing. + +That's sort of trivial. + +And there's another +good, fun property + +that you may not have +noticed in those figures, + +but they never pass through +positive curvature vertex. + +So if you look at +these pictures, + +they might end at a +positive curvature vertex + +because that's where we told +the shortest path to go, + +but in the middle, they're +always crossing edges. + +This is a convex polyhedron so +everything's positive curvature + +or zero. + +In that case, the +paths can really only + +go through zero +curvature points. + +They might start +and end wherever, + +but in between, they +never hit a corner. + +Why? + +Because if you have a +positive curvature vertex-- + +I'm just going to sketch this +idea-- if you went up here + +in order to go back down +somewhere like there, + +it's always better to +shortcut a little bit + +and not go through the vertex. + +It's better to go around +one way or the other. + +I'm just going to wave my +hands at that, but it's true. + +So what? + +Shortest paths are going to +be a really powerful tool + +for finding unfoldings. + +In particular, I want to +define the star, that picture, + +of all shortest +paths from one point. + +And do I want points here? + +I think I want vertices. + +That's the picture that we drew. + +The interesting thing about all +the shortest paths, they all + +start from the same point, +they never hit each other. + +So not only does a +shortest path not hit + +itself, but if you take many +shortest paths, or even two + +shortest paths from a +common starting point, + +they can't hit each other. + +It could be one is +a subset of another. + +For example, if I took +the shortest path to here + +and then I also took the +shortest path to a point + +just beyond it, +well, one's going + +to be a prefix of the other. + +Other than that, they will +never cross each other. + +I'm going to just assert +that, not prove it here. + +So really, it does +look like a star. + +In fact, you could fill +in more shortest paths. + +You could take the shortest +path to here, for example, + +and it'll fit in nicely, kind +of bisect that angle in there. + +It's a very simple +kind of structure. + +It's just from a point, you +have all this stuff going out. + +They never hit each +other except at something + +called the cut locus, also +called the ridge tree. + +And these are points with +non-unique shortest paths to x. + +So we're fixing some point, x. + +So here's a simpler polyhedron. + +It's just a +square-based pyramid. + +We're picking x to be in +the middle of this face, + +and drawn in these black +lines are the shortest paths + +from x to all the vertices. + +Here, that's a straight line. + +This one, if you unfolded +it, it would be straight, + +and there's some similar +ones on the back. + +And I think this is the back +in case you want to see. + +There's one back face that you +can't see at all, C, behind B + +here, and that's +what it looks like. + +There's no shortest paths there. + +Now, there's these dashed lines. + +That's the ridge tree. + +That's the cut locus. + +And these are points on the +backside with respect to x. + +If you're going from x, +you go around behind to C, + +or you could go from x around +behind to D and then to C. + +At some point, those things meet +and are still of equal length. + +So here, if you're +trying to go to x, + +you could go around this way or +you could go around this way. + +They will be the same +length, and all the points + +with that property +are the dashed lines. + +Now, if you're familiar +with [? Vornar ?] diagrams, + +this is the [? Vornar ?] +diagram of one point, x. + +Imagine you plant grass over +your polyhedron, you light + +a fire here, it burns at +uniform speed in all directions. + +Where the fire meets +itself on the backside, + +that is the ridge tree. + +That is the +[? Vornar ?] diagram. + +So it's kind of intuitive +that it's there. + +Maybe less obvious +is that it's a tree + +and it's a spanning tree. + +It hits all the vertices. + +So it's a natural cutting. + +That's why it's +called the cut locus, + +and it works really well. + +And it's called the +source unfolding. + +Source unfolding goes +back to the mid '80s. + +A bunch of people +discovered it for + +various computational +geometry applications. + +They didn't care about +unfolding at the time. + +And it's kind of obvious after +you think about it for a while, + +trying to solve this +general unfolding problem. + +Once you have this structure, +cut along the cut locus, + +unfold the star of +shortest paths from x. + +So let's do it for this example. + +It's the same +example on the left. + +This is the star unfolding. + +I've just splayed out +everything, so at the boundary, + +I'm cutting at the dashed part. + +That's the cut locus. + +Ignore these little +dashed lines. + +Those are just edges, unfolded. + +And what's happening is that +all the shortest paths are all + +here. + +If I look at any shortest path +from x on the left diagram, + +I can map it to a line +segment starting from x. + +x was a flat vertex. + +It has 360 degrees of +material around it. + +I just chose it to be somewhere +in the middle somewhere. + +Doesn't matter other than that. + +And now there's 360 degrees of +material on the flat unfolding. + +That's great. + +And you pick any +direction here, you + +can map it to a corresponding +direction over there + +on the surface, see where +that shortest path would + +go if you kept going until +you were no longer shortest. + +When you stop being shortest, +the edge of that place + +is the ridge tree, and +that's where you cut. + +You stop your segment there. + +So it's actually pretty obvious +this thing doesn't overlap + +because all of +these shortest paths + +are going in different +directions from x. + +What you have is what we call +a star shaped polygon around x. + +Every point on the +surface is visible from x + +because we just sort of +unrolled it to be right there. + +That's the source unfolding. + +It's a little hard to +see the 3D diagrams, + +but it's actually really easy +once you draw those shortest + +paths. + +So the source unfolding +is star shaped. + +We have another unfolding +called the star unfolding, + +which is not star shaped. + +Very confusing. + +I mean, what you call one +doesn't matter too much. + +This unfolding was +mentioned in 1948 + +by Alexandrov, who +we'll be hearing + +about more in the +future, but wasn't + +improved to +non-overlap until '92. + +So this one is much less +obvious that it doesn't overlap, + +and I'm not going +to prove it here. + +But it goes back to +this idea of star. + +Say, OK, this cut locus +is nice, but let's + +focus on the star +of shortest paths + +from one point to all +the other vertices. + +Instead of keeping those paths +as the things that you unroll, + +what if we cut along them? + +It's another natural thing to +try and it turns out to work. + +So here, we cut along the star. + +We've already +proved this result, + +every convex polyhedron +is generally unfoldable. + +Just with that picture, +it's very easy. + +But hey, it's fun to have more. + +And this is what the +star unfolding looks + +like for the same example. + +This is a little less obvious, +but if you think about it, + +the star, the set +of all shortest + +paths to all the vertices, +is a spanning tree. + +It hits all the vertices +because we told it to, + +and it's a tree +because it's just + +all these edges coming +together at a point. + +So it's a natural cutting also. + +And magically it works. + +How it works is a +little less obvious. + +You see here the ridge tree +drawn on the unfolding, + +and you can see all the +parts and map the letter E, + +this is the bottom square, +and stays connected. + +It's just like you +reattach everything + +around the ridge tree +and it doesn't overlap. + +It's quite difficult, I think, +to give intuition why this + +doesn't overlap, but it doesn't. + +I'll wave my hands +at some point when + +we have the necessary +tools to prove it, + +I can mention how it's done. + +But we don't have them yet. + +We'll get them in a couple +of lectures, I think. + +These results can be extended +also in various directions. + +Let me tell you briefly +about some extensions. + +For a long time, these +were the two ways + +to solve that problem +and that was sort of it. + +It would be nice, for example, +to have some general family + +of unfoldings that includes the +star unfolding and the source + +unfolding and there's +something in the middle, + +but we don't necessarily +know what that is. + +Do you have a question? + +AUDIENCE: [INAUDIBLE]? + +PROFESSOR: How do you find +the creases is your question? + +You find the creases because +you know for every point + +here where it was +on the surface, + +and if it was on an edge, +then it's a crease point. + +That's the easy way to do it. + +I don't know if that's +a satisfactory answer, + +but it can be done. + +AUDIENCE: Does it matter +where you choose x to be? + +PROFESSOR: Does it matter +where you choose x to be? + +It will change the unfolding. + +It will never overlap, +but in that sense + +there's a whole family +of star unfoldings, + +depending on where you move x. + +There's a whole family +of source unfoldings + +depending on where you move x. + +AUDIENCE: Does it make it +more efficient, any choice? + +PROFESSOR: I mean, +some of the unfoldings + +might have more cuts, +some might have less cuts. + +You're going to +get more cuts when + +you have-- depends +how you count. + +In some sense, there's only +n cuts, n shortest paths. + +But a shortest path +might cut over many faces + +or it might just +cut over one face. + +Depends where x is. + +If you choose x to +be in a nice place, + +maybe you could get +away with fewer cuts + +and have to do less welding, but +there's no theory about that. + +More questions. + +AUDIENCE: So it doesn't +matter where you put x. + +If it works at one spot, it +basically works at every spot. + +[INAUDIBLE]? + +PROFESSOR: For +convex polyhedra, it + +works no matter where you put x. + +For non-convex polyhedra, some +x's might work, some might not. + +Here, let me show you. + +Here's more star unfoldings. + +Cool. + +They're really crazy looking +and not really star shaped. + +There isn't one point +that can see everything. + +They look kind of spiky like a +star, but it's quite different. + +These are random +points on a sphere, + +like take 42 random points on +a sphere, take the convex hull, + +then take a star unfolding. + +Here's an example with +a non-convex polyhedron. + +So one thing we hoped for +for a little while briefly + +was that if you only had one +vertex of negative curvature, + +which is this one, maybe if +you choose x to be right there + +and did the star +unfolding, because that + +cuts x into lots of +little tiny pieces, then + +maybe it would unfold about +overlap, but it doesn't work. + +We were destroyed. + +In fact, you can +show neither of them + +will work in general for +a non-convex polyhedra, + +so there's no hope of +solving this problem + +with these techniques, at least +with these exact algorithms. + +You might get lucky, +but most of the time, + +I think they won't work. + +Currently, x is a point. + +You can actually +let x be-- I guess + +I'm not going to +be safe-- I'm going + +to call it a geodesic path. + +There's some restrictions +on when this is allowed, + +but the idea is you +have your surface, + +you take some straight +path on the surface, + +and then you take +shortest paths from there. + +And if you just think +about the source unfolding + +where you keep x intact +and unfold from there, + +the picture is +going to look like, + +well, you have +this straight line + +when you unfold that +thing, and then you + +have this nice star +of stuff around it. + +And under some +simple conditions, + +that will work without overlap. + +What's more impressive is +that the star unfolding + +works from a source like that. + +Again, there are +some restrictions + +on x that I'm not +going to define here, + +but it can be done. + +These are two very recent +papers by O'Rourke and Itoh + +and Vilku from the +last two years. + +So that's exciting. + +We now have four general methods +for unfolding convex polyhedra. + +Again, these are big families. + +You can choose +any geodesic path. + +Maybe some are +nicer than others. + +You can do higher dimensions. + +Star unfolding doesn't +really make sense + +in higher dimensions. + +I don't think I've +thought about it much, + +but source unfolding +makes sense. + +So you have some four polytopes, +a little hard to imagine. + +You take some point and +just radiate out from there, + +unfold like that until you hit +yourself, and then you stop, + +and that works in any dimension. + +Source unfolding works +in any dimension. + +That's fairly recent, +2003, Miller and Pak. + +Another thing you can do +is continuous blooming. + +This is an idea posed by +Connolly several years + +back and then solved +last year, I guess. + +It was presented in Japan. + +This is about folded states +versus folding motions, + +an issue we have thought +about many times in origami. + +It was easy for any +polygonal piece of paper. + +We could go from +unfolded to folded state + +by a continuous motion +without self intersection. + +For linkages, it +was the big deal. + +It was all about, can +we get from a to b? + +For convex polyhedra, you can +do it, continuous blooming. + +This is in the middle of an +algorithm of continuously + +blooming the source unfolding. + +So here's our point x. + +This is the cube, and +the source unfolding + +of a cube for this +point x in the center + +of a face, these four vertical +lines and then a little x + +on the top side. + +The algorithm unfolds +one edge at a time + +but in a very specific order. + +So it ends up unfolding this +entire house shape first, + +and then it's done +one edge of this one, + +and then it's going to fold +the other one down and then + +unfold one, two for the +backside, and then one, + +two for the left side. + +And you can show that +will not self intersect + +as long as you had +a convex polyhedron. + +It's not obvious but it's true. + +There are some other +results that if you + +have any unfolding that doesn't +self intersect at the end, + +you can add some cuts and make +it actually continuously bloom. + +It's kind of like +hinged dissections. + +It may not work by +itself, but you'd + +cut the pieces into smaller +pieces and then it will work. + +That's pretty good news, +and source unfolding just + +works as is. + +I might talk about that +some future lecture. + +Not known, for example, whether +the star unfolding continuously + +blooms. + +That sounds a +little scary to me. + +We don't actually have +an unfolding of a convex + +polyhedron that does +not continuously bloom. + +I think there should be one, +but that's an open problem. + +Is this always possible, or +is there some crazy collection + +of cuts that you cannot escape? + +That's that, general +unfolding of convex polyhedra. + +Let's turn to the-- +it's not the last topic. + +We still want to +cover both of these. + +Next topic is edge unfolding +of convex polyhedra. + +Now, this problem, +as I said, goes + +back to 1525, +implicitly at least, + +by this guy, Albrecht +Durer, who was a cool guy. + +This is Renaissance time. + +He did many different things. + +I guess painter is maybe +his primary profession, + +but he did a lot of +different things. + +He studied early perspective, +all that good stuff. + +This is one of +his famous prints. + +It was actually on display +at the MFA last year, + +I got to see it, and it +has a little polyhedron + +thrown in there. + +It's a nice polyhedron. + +How did he draw them? + +Well, he probably built +models out of some material. + +And he was just +generally interested + +in the third dimension +and understanding + +how all these things worked, and +so he made a lot of unfoldings + +in this book. + +This is the original title. + +Here's a translation. + +Titles were a lot +longer in those days. + +The Painter's Manual +is what I usually + +call it, "A Manual of +Measurement of Lines, Areas, + +and Solids by Means +of Compass and Ruler + +Assembled by Albrecht Durer for +the Use of all Lovers of Art + +with Appropriate +Illustrations Arranged + +to be Printed in +the Year MDXXV." + +And I don't even know what the +subtitle is, but there you go. + +If you read German, +I'm told this + +is a challenge because +of the old script. + +So unfoldings like this. + +He did mostly Archimedian +solids in this book. + +This book is several +hundred pages long. + +I have a copy. + +This is a +cuboctahedron unfolded. + +He is only cutting along edges, +and he liked this, I presume, + +for building models. + +Here's a fancy +one, the snub cube. + +This one, I think, +might have an error. + +A couple of them have very small +errors, but for the most part, + +he was the inventor +of edge unfolding. + +Now, he didn't ask, is this +always possible, but we did. + +Mathematicians did in +1976, I believe, or '85. + +'75, G. C. Shephard, geometer. + +He was the first one +to write it in a paper, + +does every convex polyhedron +have an edge unfolding? + +So what can I tell you +about this problem? + +It's hard. + +Many people have +thought about it. + +I'm not really sure +that it's possible. + +A lot of people do, though. + +It's possible for +a lot of polyhedra. + +In fact, every polyhedron +we've tried to unfold we + +have eventually unfolded-- +convex polyhedron. + +Simple set of examples are +the Archimedian solids. + +Doesn't take that much effort to +find unfoldings of all of them. + +You can do this with exhaustive +search or just playing around. + +A lot of people have +done this over the years. + +This is all the +unfoldings of those guys. + +There's a lot of +heuristic software + +for actually doing this. + +I think the coolest one +right now is Pepakura. + +If you want to build a +paper model of something, + +you have a 3D model +thrown into Pepakura + +and it'll probably give you +a one piece unfolding, even + +for non-convex shapes. + +Even though it's +not always possible, + +it'll do edge +cuttings, it'll try + +to do some exhaustive search, +and usually does pretty well. + +Sometimes it'll use +multiple pieces. + +That's the catch. + +There's a link in +the lecture notes. + +The most thorough +mathematical search + +is by this guy, Wolfram +Schlickenrieder, + +who wrote the equivalent +of a master's thesis + +in Berlin 13 years ago. + +I just wrote to him +about it yesterday. + +I was like, hey, +this is cool stuff. + +Can I show it in my lecture? + +He was like, yeah, it lives on. + +He had a class of 10 +different algorithms, + +around that many, +possible algorithms + +for unfolding all +convex polyhedra, + +and then he came up with +a dozen different families + +of polyhedra. + +I don't have the polyhedra +drawn here, just the unfoldings. + +They're generators of +big classes of polyhedra. + +He applied every +algorithm to every class. + +Ideally, you get an algorithm +that works for all classes + +or you find a class that +foils all algorithms. + +Sadly, he found neither. + +Every algorithm was +foiled by some example, + +yet every example was +foiled by some algorithm. + +It's really annoying, but here's +some examples where they fail. + +They just barely fail, just a +couple triangles are messed up. + +Little squares are messed up. + +I think these are called +the turtle polyhedra. + +It's like a big, flat thing +and then a dome on top. + +So inconclusive, I +guess, is the answer. + +There was one algorithm that +had a degree of freedom. + +You had to choose +a direction, then + +you cut along all the edges +that are most in that direction. + +And there was a conjecture +on the table from this thesis + +that maybe for every +polyhedron, there + +is a direction that +works, but then + +that was destroyed +four years ago. + +Brendan Lucier from Waterloo +proved that that's not true. + +He found a polyhedron +that doesn't + +work from any direction. + +So at the moment, we have +no candidate algorithms, + +which makes me worry whether +this could possibly be true. + +We have some more bad examples. + +Here are some annoying things, +like a cube with a corner + +cut off. + +It's a very local thing, but +you can mess up really easily. + +It's actually quite common +to mess up, I would say, + +even though for things +like Archimedian, + +it's much harder to mess up. + +Simplest polyhedron that messes +up is this sliver tetrahedron. + +So the polyhedron +is drawn at the top. + +It's a little hard to +see, but on the backside, + +there's an edge like +that, if you can imagine. + +So it's almost +flat, so that's why + +it's drawn flat, and +the four corners, + +like a tetrahedron +should have, four faces, + +the front two triangles +and the back two + +triangles with the +line that I drew. + +And if you unfold it in a simple +way, you just cut from a to b, + +it unfolds like +this, no problem. + +But if you unfold +the wrong way, which + +is to cut both of +the diagonal lines, + +then you end up with the +spears that cross each other, + +so you really have +to be careful. + +In fact, if you take +a random polyhedron-- + +I choose 80 points on a +sphere, I take the convex hull. + +It's a very nice, round +sphere-like polyhedron. + +And I look at all +the unfoldings-- + +this is probably not +all the unfoldings, + +but I randomly generate +unfoldings, and I evaluate, + +what is the observed +probability that I get overlap? + +And it's very close to 100%. + +The conjecture is that +as n goes to infinity, + +the probability of +overlap goes to 1. + +We don't have a proof of that. + +That would be nice to prove. + +There's good reason to +believe that's easy to prove + +or that it's true, let's +say, that there is a proof. + +I don't know how to +actually formalize it. + +This is some work +from the late '80s. + +Just because most +unfoldings fail + +doesn't mean there isn't +one unfolding that works. + +If I were to try to prove that +there is an unfolding that + +works, here's my best hope, +and it ties into some things + +that we've seen +with tensegrities. + +If you take a really big +polyhedron, which is the case + +you worry about, and you look +at a small portion of it, + +that portion will be +almost completely flat. + +Locally, this thing +is mostly flat. + +Instead of thinking +about the big polyhedron, + +if we at least wanted to +get it to work in any patch, + +think about the case of +an almost flat polyhedron. + +So it's like a little dome. + +It has boundary now. + +Makes life a little +harder, but let's say + +it's a nice, convex boundary. + +This is a convex dome. + +It's actually polyhedral. + +Well, let's make it +super, super flat. + +So we have this z-coordinate. + +Scale z to squash it +down into the plane. + +What's nice about +this is then you + +can think of your +convex polyhedron + +just as some drawing +in the plane. + +So here maybe is my +convex polyhedron. + +Now, in fact, each +of these vertices + +is lifted a tiny amount, +some infinitesimal amount, + +but you can think +of it in the plane. + +These are convex faces. + +We know this thing can be +lifted to a convex polyhedron. + +That lifting is +a positive stress + +on all the edges except +the boundary edges. + +Maybe that stress gives +you some useful structure. + +If there's any hope +of this working, + +that structure better be useful, +but I don't know how to use it. + +But in particular, +open question. + +If I give you a super +shallow, arbitrarily + +shallow, convex polyhedral +dome, can it be unfolded? + +I don't know. + +Maybe we'll work on it +in the problem session. + +Haven't thought +about it for awhile. + +That's if you want +to solve everything. + +What if you just want to +solve some special cases? + +That is a special case +motivated by the general case. + +Well, you can solve the +case of a polyhedron + +with at most six vertices. + +That's as far as we've gotten. + +You can solve some simple +examples like pyramids + +if you take any convex +polygon, doesn't + +have to be irregular +or anything, + +and then you take a point +and you take the convex hull. + +So that's a polyhedron +and it unfolds. + +How does it unfold? + +Any suggestions where to cut? + +How? + +AUDIENCE: From the top? + +PROFESSOR: From the top. + +Yeah, just cut here. + +Here, we're only allowed +to cut along edges. + +This is called the +volcano unfolding. + +What do we have? + +Like that, and then there's +just a bunch of triangles. + +What's nice about +the volcano unfolding + +is if you look at these +perpendicular strips here, + +those triangles will fit inside +those perpendicular strips, + +and therefore they won't +intersect each other + +because these strips don't +intersect each other. + +You could probably +even continuously bloom + +this, no problem. + +So a very simple example, +easy to do with volcanoes. + +That's the so-called pyramid. + +Prism, a little bit more +interesting, but not by much. + +You take some polygon. + +Again, doesn't +have to be regular, + +but you take two copies of +it vertically offset, take + +the convex hull. + +This one you can +cut in two ways. + +You could do a +volcano-like thing + +where you cut all +the vertical edges + +and then you cut all but +one of the bottom edges. + +Then you'll have basically a +volcano with little rectangles + +hanging off all the sides. + +And then there's another copy, +the bottom copy of this face, + +and it just hangs out +over here, and you + +could prove that that +won't hit anybody + +in this very simple situation. + +There's another unfolding, +though, that I mention + +because it's useful +for other things, + +and it's so-called +band unfolding. + +Band unfolding, I +want to keep intact + +the radial band around the +thing, maybe like this. + +What do I want to do +to keep that edge? + +Cut, cut. + +So I cut on all the +top edges except one, + +I cut on all the bottom +edges except the same one, + +and then I also cut +this vertical edge. + +So what I should get +is I get my top face, + +then I get a +rectangle, then I get + +the band that goes +around the outside, + +and then I get another copy +of my shape, the bottom side. + +This is what we +call band unfolding. + +There's some nice theorems about +band unfoldings working out. + +Let me get to more +interesting polyhedra. + +These are some +pretty simple cases, + +but we don't know very +much on the positive side. + +Prismoid. + +Suppose you take a polygon, +and you basically inset it. + +So I want to make a new +version of the polygon + +where all of the angles match, +so these edges are parallel + +to each other. + +I think, actually, the +lengths can change. + +And then you take +the convex hull. + +These unfold with the +volcano unfolding. + +It's a little more +subtle to prove + +but it's proved in the textbook. + +Edges have to stay parallel. + +I think that might +force something. + +I'm not quite sure, +but the constraints + +are that the edges +have to be parallel + +and the angles have to be equal. + +Dome. + +Dome is actually in +some ways simpler. + +You take some base, and then +I want a whole bunch of faces + +that all touch the base. + +So in general, it's going to be +like a tree of faces, something + +like this. + +Every face has to touch +an edge of the base. + +These also unfold, and +also with a volcano. + +This is proved also +in the textbook. + +Both results are +by Joe O'Rourke. + +Prismatoid. + +This is the coolest +special case I'm + +going to talk about, +the most interesting. + +I take some convex polygon, +and then in a parallel offset, + +I take some other +convex polygon-- + +no relation to each +other except that they're + +in parallel planes-- +and then I take + +the convex hull, +something like that. + +This one, sadly, is open. + +Now, what we do know, +and this is related + +to the band +unfolding, if you look + +at the band around the +sides of this prismatoid + +and just unfold +that by itself, that + +will not self intersect, +and that's quite nontrivial, + +the proof. + +But if you just +unroll the side faces, + +they will wander around but +they won't hit themselves. + +The only remaining +problem is, where + +does the top and +the bottom face go? + +I think I have an example +where that's a little dicey. + +Prism. + +Prismoid. + +That gives you an +answer to your offset. + +So they can be sheared +away from each other, + +but this is a prismoid. + +All of the sides are parallel +and the angles match, a and b. + +Here is the volcano +unfolding of the prismoid, + +and here's showing that it's +not so obvious that it always + +works. + +If you're not careful where +you put the top face-- so this + +is a on top of b +in plan-- you could + +attach a to any of these faces. + +You have to choose +one that's not + +so inside because +it's overlapping here. + +But if you choose +the outermost one, + +it works and you can prove that. + +This is the dome. + +You can even have +overhang and they + +will unfold, volcano style. + +You no longer have those +nice perpendicular wedges + +to say everything is disjoined. + +But it still turns out. + +Nothing intersects. + +Here's the prismatoid +I wanted to show you. + +This one's actually almost flat. + +So a is this triangle right on +top of b, the triangle beneath. + +You take the convex +hull and you get + +all those edges on the outside. + +And if you're not careful-- +this is more volcano + +style unfolding-- but +you can get overlap. + +One thing we do know, +this is kind of weird. + +If you try to go more general, +and instead of taking a convex + +polygon on the top and a +convex polygon on the bottom, + +instead you take a +smooth convex curve + +on the top and a +smooth convex curve + +on the bottom, which is getting +weird because now there's + +infinitely many +vertices and going + +to be infinitely many cuts. + +But there is a natural +notion of unfolding + +which sort of takes +the continuum. + +You take all those lines +that go from one side + +to the other, the rule +lines of the convex shape, + +and you just unfold them. + +You don't actually preserve +area when you do this. + +It's not a valid unfolding +in the usual sense, + +but it's a natural +generalization + +of unfolding to smooth shapes. + +You can prove, well, that part's +going to work just fine if you + +just volcano it, and +then you can actually + +find a place for the top face. + +Those are the special +cases we know, + +and even some pretty simple +cases that we don't know, + +although it's almost there. + +One more open problem. + +Just mention this because +it's a fun problem. + +So again, I want to edge +unfold all convex polyhedra, + +but I allow multiple +pieces to make + +the problem a little easier. + +So let's say I have a +polyhedron with f faces. + +I want to know how few +pieces could I get away with? + +The big open problem is, can +I get away with one piece? + +What if you make it easier? + +What if I just want, say, +little o of f pieces? + +Smaller than any +constant times f. + +This is open. + +What we do know is +some constant times + +f where the constant +is less than 1. + +Best constant I have +written here is 1/2. + +There is a better +bound, but I think + +it's not so easy to +summarize in this form. + +So you can get a +little less than half + +the faces' number of pieces, +but that's pretty pathetic. + +It's a problem that seemed +like it would be a good idea, + +but so far it hasn't seemed to +make the problem much easier. + +What do I mean by pieces? + +Well, we're all about +one piece unfolding, + +so now your cutting +can have cycles in it + +and disconnect the surface +into multiple parts. + +AUDIENCE: [INAUDIBLE]. + +PROFESSOR: Multiple +connected components. + +The tricky part is +to pair up the faces + +so that everybody has a mate. + +That's not always possible. + +AUDIENCE: [INAUDIBLE]? + +PROFESSOR: Yeah. + +You would hope that one +third, but-- I mean, + +you can do lots of +little local arguments + +and prove this constant, +but the big question + +is, can you get less +than a constant? + +So last topic for today is edge +unfolding non-convex polyhedra. + +Sort of did that +problem addressed, + +and now this is not +always possible. + +So I want to give you a +polyhedron where you cannot + +edge unfold it. + +This is actually pretty easy, +and we did it way back in '98 + +when we started +working on folding, + +but it's kind of cheating. + +This is a box on a box, +and the only edges here + +are the edges of the two boxes. + +There's no edges connecting +the outside of this face + +to the inside of that face. + +That face here is a donut. + +It's a square donut. + +So if you're only cutting along +edges, that face is intact. + +Now I ask you, where +does the top box go? + +The top box has five +square faces, not six. + +There's nothing on the bottom. + +And somehow, it has to +be attached to the rest + +if I want one piece. + +That means that all +five faces fit in here, + +but there's only room +for one in terms of area + +so you're screwed. + +But this is cheating because +what I really wanted to do + +was generalize this +problem, edge unfolding + +of convex polyhedra. + +Now, I know they're not +going to look convex, + +but that thing is +really not convex. + +It's really not +convex in the sense + +that you have this face that is +not even topologically a disk. + +It has a hole in it. + +Convex polyhedra +don't have that. + +So in some sense, this +is a topological problem, + +you might say. + +And you might hope that if +I looked at polyhedra that + +are topologically +convex, maybe those + +would unfold by edge cuts. + +"Topologically convex" +means that if you just + +move the vertices around but +preserve the edge structure, + +then it becomes a +convex polyhedron. + +In other words, I take a +convex polyhedron, which + +we think maybe has +an edge unfolding, + +and then I just pull +the vertices around + +but preserve all the faces. + +Then can you edge unfold those? + +And the answer is no. + +I have one more example +before we get there. + +This polyhedron, at least +all the faces are disks. + +There's no holes. + +So it's a cube with +little bites taken out + +of all the edges, same paper. + +And this thing also +does not unfold. + +It's a little less obvious. + +What's cheating about +this example is you + +have two faces, like this +purple one and the yellow one, + +that share two different edges. + +And for convex polyhedra, +two faces either + +share an edge or a +vertex or nothing, + +but they can't reach +around and do to joins. + +Again, this is not topologically +convex, but this is. + +So this is two views +of the same thing, + +and if I take these spikes and +I just push that vertex down + +to be really close to this +triangle, this will be convex. + +So it's just a convex +polyhedron that I + +pull on four of the points. + +Same facial structure. + +This has no edge unfolding +and we're going to prove that. + +This example is even +stronger in that + +all the faces are triangles. + +So what we're going to +do is take this thing. + +It's kind of appropriate +for this season. + +So I've got a +tetrahedral spike on top. + +Think of that as going +out of the board. + +And then in the plane of +the board is this triangle, + +and then I just add +in all the edges + +to make it a triangulation. + +Adding edges is a +worry because that's + +where we're allowed +to cut, so you really + +have to worry about +all those edges we add. + +If we add them in +that way, I claim, + +you take this-- we call +it the witch's hat-- + +then you multiply, in some +sense, by a tetrahedron, + +meaning I take four +copies of this hat, + +I put one on each face +of the tetrahedron, + +and you get that example. + +Here's one witch's hat and +they're just joined along edges + +to make the tetrahedron. + +You could do this +with bigger polyhedra, + +too, like octahedron, anything +with equilateral triangles, + +but tetrahedron is the +smallest where it works. + +Just two of them glued face +to face would not work, + +but this way does work. + +Is that true? + +Now I've got to think about two +of them joined face to face. + +I don't think it works. + +Otherwise, we would +have done that. + +Oh yes, I think I see why. + +Why doesn't this work? + +I should say it doesn't work +if the spikes are really tall + +and the base is really flat. + +I'm going to define +what "really" means, + +but we'll get there. + +So here's our witch's hat. + +When this spike is really +tall, these angles, alpha, + +are very close to 90, +a little bit under 90. + +This angle in the floor here-- +well, this angle in the floor + +is about 60, probably +actually is exactly 60. + +This is an equilateral triangle. + +So if this thing is very flat, +this angle will be almost 300 + +because it's 360 minus 60. + +It'll be a little bit less +than 300 but almost 300. + +These matter. + +In particular, the +total sum of angles + +here is 300 plus twice +90, which is big. + +It's bigger than 360. + +That's the point. + +In fact, 300 plus one +of these angles, 90, + +would be almost 390, +which is way above 360. + +So this has negative curvature, +and even if you cut out + +one of the spike +triangles, it would still + +have negative curvature. + +That's going to be bad +news because let's just + +imagine for the moment. + +We know unfolding +things with boundary + +is hard, but let's pretend +for now that you wanted + +to unfold a hat in isolation. + +You wanted to unfold it into +one piece without overlap. + +Think about what you could do. + +I have to cut with +a spanning forest, + +I guess, meaning +it's acyclic, it's + +got to hit all the vertices. + +There's only four vertices here. + +How could I hit all the +vertices with a forest? + +You may recall from way back +when that trees have leaves. + +Every tree has at +least two leaves. + +Here I might have multiple +trees, maybe, but unlikely, + +and I have to have +at least to leaves. + +Where could those two leaves be? + +Could they be at any leaves +or vertices at degree one? + +Could they be at any of +these three vertices? + +No, because they have +negative curvature. + +We know a vertex with +negative curvature + +has to have at least +two cuts incident to it. + +You can't stop at +these three vertices. + +That only leaves one +vertex and the boundary. + +So the only thing +you can do if you + +want to visit all the +vertices and start somewhere + +on the boundary and get +to the x, get to the peak. + +That's all you can do. + +You couldn't have multiple +connections to the boundary + +because then you +would disconnect. + +Then there's really +only two choices + +and they're +reflectionally symmetric. + +And we're only allowed +to go along edges. + +It's super constrained. + +You can go here, walk +around, and go up, + +or you can walk around +the other way and go up. + +Those are actually slightly +different because you + +have two choices of which +edge to follow here. + +They're both screwed +because if you + +look at this point, the +white dot, or the white dot + +up there, what remains +here on the outside + +is almost 300 degrees +of material on the base + +plus one of the 90 degree +faces, the back one + +that you can't see. + +It's easier to see here. + +You have the 300 +degrees on the bottom + +and then the white face +is still attached to it, + +and that's almost 390. + +When you flatten +that thing, it's + +going to overlap +itself at that point. + +Bad news. + +So this just says, if I +look at a hat in isolation, + +it can't unfold, but that's +not what I care about. + +I care about four of +them joined together. + +Suppose you had some +unfolding of the whole thing, + +and then I look +at, well, what cuts + +happen within the witch's hat? + +I know the witch's hat +cannot remain in one piece. + +Therefore, it must +be disconnected + +into multiple pieces, +something like this. + +Again, the cuts have to visit +all the vertices somehow, + +but we know from the +perspective of a single hat, + +that hat must split +into two parts. + +There are lots of things +you could consider. + +Let's suppose this is +possible, not even worry + +about these kinds of pictures. + +Well, I claim we have a problem. + +Here's a tetrahedron. + +These vertices are all +the same point, actually. + +I've just unfolded +the tetrahedron + +because it's way easier +to draw in two dimensions. + +So if I look at the hat +that is on this triangle, + +this hat gets disconnected +into two parts. + +There's only three +connection points + +to the rest of the world. + +So what these pictures +have to look like is they + +connect two of the vertices +by a collection of cuts. + +If you're going to +cut into two halves, + +you've got to have +a path across, + +and there's only three +vertices to visit. + +There's some collection +of cuts that go from, + +let's say, this +vertex to this vertex. + +At this point, +everything's symmetric. + +Maybe it would be more obvious +if I started the center. + +It could be from +here to there, could + +be from here to there or from +here to there, but at least one + +of those things exist, +and by rotational symmetry + +of this diagram, +say it's that one. + +Well, what happens to this face? + +Could there be +something like this? + +No, because then this +would be disconnected + +from the rest of the world. + +So suddenly, this +hat is constrained. + +Maybe it could look like this. + +You have a choice. + +It could look like +that or like that, + +but by reflectional +symmetry, same thing. + +So let's say this one. + +Remember, x is the +same everywhere. + +Well, that means +this is impossible + +because this edge is +actually glued to this edge, + +and so then this thing +would be disconnected + +from the rest of the world. + +So there's a couple +of possibilities. + +It could look like this, +or it could look like this. + +It was one of those +two for this face. + +We've got one face left. + +This is impossible because +this edge glues to this one, + +so imagine this thing being +picked up and moved over here. + +So we have a wiggly line +here and then this stuff, + +and so that would +be disconnected + +from the rest of the world, +so that can't happen. + +What about this one? + +Is that the harder one? + +I don't know. + +It's been a while since +I've used the argument. + +If we have this +together with this, + +that's clearly bad because +that forms a cycle. + +No good. + +But what if I have this +together with this one? + +It gets hard to see. + +It's bad. + +It's a cycle. + +It starts and ends at x, +and if you fold it up right, + +you'll see there's really +two sides to that cycle. + +It's actually forced, +so that's bad. + +All right, one more +choice, this one. + +If I do this together +with this one, + +that's going to be bad +because that's a cycle. + +We start and end at x. + +What if I do this +one and that one? + +Well, that's also +bad because here's + +a cycle that starts +at x, ends at x. + +This and this form the +inner of the cycle. + +All cases are bad, +so no edge unfolding. + +Tragic. + +We can think briefly about +the case-- do I have time? + +I have 10 seconds. + +About the case where +there are two triangles. + +I guess I should +draw them like this. + +So this point is the +same as this point. + +So if I try to simplify this, +instead of using four hats, + +I just use two hats, +put one here, one here. + +Then I could do something +like this, I think, + +and maybe that's OK if +there's no cycle formed there. + +So we really needed the +tetrahedron somehow. + +I think it does work for +octahedron and larger also, + +but just two triangles +is not enough. + +And that is unfolding. + +We did not always edge foldable +for general polyhedra, even + +topologically convex polyhedra. + +Next time, we'll talk more +about general unfolding + +of arbitrary polyhedra. \ No newline at end of file diff --git a/vPQ9a_xIqRg.txt b/vPQ9a_xIqRg.txt new file mode 100644 index 0000000000000000000000000000000000000000..30aa4c4b141da857e5cf2df30176eee1251fcc6e --- /dev/null +++ b/vPQ9a_xIqRg.txt @@ -0,0 +1,2851 @@ +The following content is +provided under a Creative + +Commons License. + +Your support will help MIT +OpenCourseWare continue to + +offer high-quality educational +resources for free. + +To make a donation or view +additional materials from + +hundreds of MIT courses, visit +MIT OpenCourseWare at + +ocw.mit.edu. + +PROFESSOR: Let's get started. + +Settle down. + +Settle down. + +Welcome to 3.091. + +I'm Donald Sadoway and I'm going +to be your instructor + +this semester. + +So what I want to do today +is to introduce my plans. + +I've got plans for you. + +Plans for learning. + +I want to talk a little bit +today about those plans, + +introduce myself, introduce +my class curriculum-- + +the path forward. + +So let me begin by saying that +3.091 is the most important + +class you will take at MIT. + +It's true. + +But, you know, anybody who +stands in front of you to + +lecture should say the same +thing about his or her class. + +If they don't believe that they +shouldn't be standing in + +front of you lecturing. + +The difference is when +I say it, I'm right. + +[LAUGHTER] + +PROFESSOR: And it's not just +an opinion, it's because of + +the content of 3.091. + +3.091 is about chemistry. + +It's about the central science, +but it's not just + +about any old chemistry. + +This isn't a class that you +could take anywhere else in + +this country. + +This is the only place that +you can take 3.091. + +3.091 is solid state +chemistry. + +Now why do we talk about +solid state chemistry? + +Because engineering systems +are made of solids. + +Now I know what you're +thinking-- oh, he said solid + +state, he's going to talk +about the chemistry that + +constitutes his laptop computer +or the chemistry that + +constitutes this +laser pointer. + +And that's true. + +We will talk about +that chemistry. + +But we will also talk +about soft matter. + +We as human beings are +chemical machines. + +When this hand changes shape, +it is a polymer that is + +changing conformality. + +These eyes are photodetectors, +band gap of about + +two electron volts. + +They're not made of +gallium nitride. + +They're made of organic +compounds. + +Inside, what supports us, +it's a ceramic skeleton. + +So solid state chemistry +describes + +life science as well. + +Well, what we're going +to learn in + +3.091 is the rudiments. + +We're going to learn +the rudiments. + +So what I'm going to do today is +now go through some of the + +basic organization. + +So tomorrow you're going +to meet your recitation + +instructors and get to know each +other and get to know the + +recitation instructor. + +Today I'll say a few words about +myself so you know who's + +standing in front of you. + +I graduated from the University +of Toronto in + +chemical metallurgy, came down +here in 1977 to spend a year + +as a postdoctoral fellow and, I +guess, I lost track of time. + +Now what's my research? + +My research is in +electrochemistry. + +Electrochemistry is the most +important branch of chemistry. + +Do you notice some theme in +my professional life? + +See, I have tenure. + +So what does that mean? + +It means you find your passion +and pursue it. + +You don't waste time on +trivia, all right? + +And that's what I urge +you to do: Find your + +passion and pursue it. + +So what's my passion? + +My passion is electrochemistry +in nonaqueous media. + +Anything but water. + +Let the rest of the world +work on water. + +I work on molten salts, ionic +liquids, and polymers. + +And what's the reason +for this? + +There's an application. + +I'm in the School +of Engineering. + +So I'm interested in +environmentally sound + +technologies for metal +production, all right? + +Right now looking at titanium, +iron recycling as well. + +I'm also interested in +electrochemistry as it applies + +to energy storage, energy +storage for mobile power. + +See this gal here? + +She's got the cell phone. + +She's not even looking +where she's driving. + +[LAUGHTER] + +PROFESSOR: So making safe +batteries out of + +earth-abundant, accessible +materials for portable power, + +ultimately to drive the car with +electrons, electric fuel, + +to eliminate this country's + +dependence on imported petroleum. + +We can do it. + +How? + +By inventing. + +By inventing. + +And the way we're going to +invent is to learn the lessons + +in 3.091 that will give us the +chemistry we need to invent a + +battery that can send that car +250 miles on a single charge, + +and put it in a show room for +the same price as a car with + +an internal combustion engine. + +The only thing that stands +between that image and where + +we are today is invention, and +the requisite material is + +right here in this class. + +We're also looking at +colossal batteries. + +Store the grid. + +Enable renewables, +wind, solar. + +And then, lastly, let's never +forget about dreaming. + +So if we want to dream and +imagine that man will return + +to the moon or maybe even go to +Mars, we're going to have + +to be able to produce oxygen. + +We'll live like the pioneers, +produce oxygen from local + +resources, produce structural +metals, and even produce + +photovoltaic silicon so they can +generate their own energy + +from local resources. + +And so electrochemistry is the +key enabler for that as well. + +So now let's turn to the whole +underpinning of 3.091. + +If we take a look at the +performance of any engineering + +system it's a combination +of the design and the + +construction. + +Now the construction is both the +workmanship and the choice + +of materials. + +Now how do we choose +materials? + +We choose them on the basis +of their properties. + +So, for example, here's an + +application: a beverage container. + +This one I'm holding is made +out of an aluminum alloy. + +It's a metal. + +When I was your age, they +had steel beverage cans. + +You can take this same beverage +and contain it in a + +glass bottle. + +You can contain it in +a polymer bottle. + +Why do we make those +various choices? + +Because they have the right +mix of properties. + +Now how do you determine +the properties? + +Properties obviously are +determined by the composition. + +We wouldn't make this thing +out of sodium chloride. + +It would dissolve. + +So composition is important, +but atomic arrangement is + +important as well. + +Example is 1/2-inch-thick +pine board compared to a + +1/2-inch-thick piece +of plywood. + +Both pine, but the +1/2-inch-thick pine board is + +one solid pine board. + +I can take that pine board and +I can fracture it if I strike + +it along the grain. + +But the 1/2-inch-thick plywood, +I can't do that + +because it's 1/8-inch sheet +pine cross-laminated. + +1/8 inch north-south, 1/8 inch +east-west. If I try to cut + +through that board, I can't +advance the fracture. + +Same composition, different +atomic arrangement. + +So the thesis of 3.091 is that +the electronic structure of + +the elements holds the key +to understanding that + +relationship between +composition, atomic + +arrangement, and properties. + +And once you have properties +that's how + +you make your selection. + +And away we go. + +And that's how we got the +syllabus of 3.091. + +So the syllabus has +two major blocks. + +The first block is general +principles of chemistry-- it's + +going to be about the +first five weeks-- + +and that's the same stuff that +you get here, 5.111, 5.112, + +the basics of electronic +structure and bonding. + +And then we part company and +in 3.091 we dig down into + +solid state chemistry. + +You don't have to take notes. + +You can relax. + +All this is going to be +burned to PDF and + +posted at the website. + +So everything that you see in +this class that goes up on the + +screen is archived for you. + +This lecture is being video +recorded right now and within + +an hour will be posted +at the website. + +So in the unlikely event that +you can't quite come to class, + +it is available. + +[LAUGHTER] + +PROFESSOR: So now what I want to +do is introduce some of the + +operational aspects +of the class. + +And we had some handouts +going around. + +If you didn't get them we +can get you extras. + +But again, this is all posted +at the website. + +So you know who I am. + +The key person in this operation +is my administrative + +assistant, Hilary Sheldon, and +she's just down the hall. + +You can roll a penny down +the hall from here + +and get to my office. + +So if you tell me you tried +looking for me, you couldn't + +find me, I know you couldn't +have been trying very hard. + +The text is a two-volume set +consisting of the text + +Chemistry: Principles, Patterns, +and Applications by + +Averill and Eldredge, and then +a second volume that consists + +of miscellaneous readings +taken from other + +Prentice Hall texts. + +And it's identical in content to +the blue book that was used + +last year and the year before. + +So if you get a copy of +that blue book, you + +don't have to buy these. + +I don't work for Prentice Hall, +I'm not trying to sell + +books, but we will take the +homeworks out of the books to + +a great extent. + +And the page numbering is the +same, so anything this year or + +the last two years +will be fine. + +If you have to buy something, +you'll have this. + +This one will come with a CD +that will get you into a + +mastering chemistry, which +is a sort of a tutorial, + +computerized system to help +you with certain homework + +problems. + +The lectures, Monday, Wednesday, +Friday, here in + +this room at 11 o'clock. + +The lecture starts at five +minutes after the hour-- + +gives you five minutes +to get in-- + +and then the lecture +stops at five + +minutes to the next hour-- + +time for you to leave and then +for the next class to arrive. + +And what I'm going to try +to do is establish + +some plug flow here. + +So what I'm going to try is to +have everybody leave by the + +exit to the north here to my +right, and there's also an + +exit over the top back. + +So leave to your left and that +way it'll be easier for the + +next class to come in. + +And maybe we can persuade the +people here before us to do + +the same and then it'll +be easy to change. + +I don't know why but there's +this sort of-- everybody has + +to charge to this door. + +And I just stand here and +watch people collide. + +And I don't know. + +Just interesting social +experiment. + +And there are two doors. + +I don't understand why people +do this, but I'm not in the + +social sciences. + +Recitations. + +Recitations will meet Tuesdays +and Thursdays. + +So you'll go to the same hour +on Tuesday and Thursday. + +The section should be +roughly 20 students. + +And that's where the question +and answer occurs. + +Here it's largely I +talk, you listen. + +I've got time for a question +like, hey, shouldn't that be a + +minus sign? + +I can take something +really quick. + +But where you get to really +interact with the instructor + +is in recitation. + +And I've given a direction to my +recitation instructors not + +to give you a fourth +and fifth lecture. + +You control the content +of the recitation. + +So you have to come +to the recitation + +prepared with questions. + +So they're supposed to walk in +and say, good morning, good + +afternoon, what are +your questions? + +And you can say, I didn't +understand the last five + +minutes of the lecture +yesterday. + +Would you do number five +on the homework? + +Would you go over secondary +bonding? + +That's the sort of thing +that's supposed + +to happen in section. + +You've been assigned +by the Registrar. + +You are forbidden to change +your section on your own. + +You can't just squat +in another section. + +We do this with the intention +of trying to keep the + +enrollment roughly uniform. + +We don't want sections growing +to 35 because then that limits + +your ability to interact. + +If you've changed classes or +you've picked up a UROP, or + +what have you, and your +situation has changed, please + +go down the hall and meet with +my assistant Hilary, who will + +then arrange to move you. + +And that way we can keep some +control over the section size. + +Again, you may not change +simply on your own. + +And it has to be with cause, +academic cause. + +You can't go in and say, I was +assigned to the 9:00 am + +section and I don't +do mornings. + +That's not going to work. + +Homework. + +Homework is very +important here. + +Homework is a little bit +different, though, in 3.091. + +You're not going to be +asked to turn in + +homework for grading. + +Instead, at the beginning of +each unit, you will be given + +homework with the +model solutions + +right at the beginning. + +This is a study aid, and you can +use the model solutions to + +help you understand the +homework material. + +Now since we're not asking you +to turn anything in and we do + +want to stimulate interest in +the homework, we found a way + +to stimulate interest. And that +is that once a week in + +section you will have +a 10-minute quiz + +based on the homework. + +That will ensure that +you've at least + +looked at the homework. + +And those weekly quizzes will +be graded, and the aggregate + +of all of those quiz scores will +constitute your homework + +grade in the subject. + +And you must take +those quizzes. + +If you don't take the quiz-- + +you got sick or some personal +emergency came up-- contact + +your recitation instructor and +within a week of the date of + +the original quiz arrange +to take a makeup. + +If you don't take the +makeup, we're going + +to give you a zero. + +And there's no dropping +of lowest score. + +Somewhere there's this in the +lore here that, oh, you can + +drop the lowest score, the +lowest two scores. + +People come to me with this +proposal and I say no. + +[LAUGHTER] + +PROFESSOR: So let's +get started. + +This is homework number one. + +It's assigned today. + +We're going to save paper-- +just go to the website-- + +and you'll be tested on +Tuesday, next Tuesday, + +September 15, at the beginning +of section. + +At the beginning of section +there'll be a 10-minute quiz + +based on that homework, +and you can get the + +homework and so on. + +By the way, here's what the +homework looks like. + +Chapter 1, Chapter +3 of Averill. + +Averill is the major text. + +We just refer to it by the +author's last name. + +So taken from Averill. + +By the way, I don't like to +use this unpleasant term + +"test." I like to refer to it as +a celebration of learning. + +[LAUGHTER] + +PROFESSOR: So it's +a celebration. + +We're going to start celebrating +on Tuesday. + +There's the website +by the way. + +You probably want to +bookmark that. + +You're probably going +to go to that a lot. + +We're going to keep celebrating, +and so we will + +have some monthly celebrations, +monthly tests, + +and they've already +been scheduled. + +And you will write those tests +during the normal class time. + +But on those days we will +spread you out a bit. + +I like to see some vacancies. + +So you will not be sitting +one next to another. + +There'll be at least one human +vacancy next to every human, + +and that way you've got room to +spread out, keep your eyes + +on your own work. + +So those are the dates +and there'll be + +more of that in time. + +Now when you take the monthly +test, I allow you to use aids. + +So everyone will be given in +recitation tomorrow a Periodic + +Table of the Elements, very +nice one, laminated one. + +So you take that with you to the +test. In fact, you should + +take this with you everywhere. + +[LAUGHTER] + +PROFESSOR: If I run into you at +Harvard Square, I want to + +see the Periodic Table, because +every educated person + +has the Periodic Table. + +You get a table of constants. + +So you'll have one of these. + +You'll get that tomorrow +as well. + +Paper copy, and on there are all +the constants so you don't + +have to remember that the +permittivity of vacuum is 8.85 + +times 10 to the minus +12 farads per meter. + +It's on there. + +I urge you to use that when +you do your homework. + +So it's always amusing to me +during the time of the first + +monthly celebration, somebody's +looking at this as + +though it's today's newspaper +and they're + +looking, where is that? + +Sort of revealing about the +intensity with which the + +homework has been embraced. + +Calculator, something to +calculate with, and I don't + +care if you bring in a graphing + +calculator or a mainframe. + +I don't care. + +[LAUGHTER] + +PROFESSOR: And you're allowed +an aid sheet, an 8 1/2-by-11 + +sheet of paper. + +And you can write on +the front, you can + +write on the back. + +You can photoreduce previous +exams down to micro-dot size. + +I don't care what you put on +it, but with this, you have + +then no excuse to say I really +understood this stuff, but I + +couldn't remember a formula. + +Actually, many students tell me +that the act of preparing + +the aid sheet organizes the +subject matter in their minds. + +They bring this with them to +the exam, and they never + +consult it, but it just soothes +the nerves and makes + +sure that everybody does well +on the monthly test. + +The weekly test, no. + +The weekly test you bring your +Periodic Table and table of + +constants, but no aid sheet. + +For the weekly test, +it's a very + +concentrated amount of material. + +And I'm not going to test your +memories, because that doesn't + +prove anything to me. + +And then, of course, the +celebration of celebrations is + +the final exam. + +[LAUGHTER] + +PROFESSOR: That's huge. + +That's a huge celebration. + +It's three hours. + +See, these are really +50 minutes. + +This is three full hours. + +The time and location will +be set by the Registrar. + +We should know by October 1. + +The final exam period is +December 14 to 18. + +And so what I urge you to do +is as soon as that schedule + +comes out and we know when all +the final exams are going to + +be held, then you book your +passage for the holidays. + +Do not get that order +reversed. + +You cannot come to me and +say, I got a really + +good price on a ticket. + +I'm going Acapulco on the 15th +of December, and your exam is + +on the 16th of December. + +I'll say, you just got +a zero on the final. + +You have to be here for that. + +You know why? + +I have to be here for that, you +can be here for that, too. + +There are about a quarter of a +million students in Boston. + +It's a great college town, but +at Christmas time, it's + +pandemonium at Logan Airport. + +So you want to book your passage +early, but you can't + +do it until you know what your +final exam obligations are. + +Grading. + +Freshman, you know, it's +pass/no record. + +Pass/no record. + +And so that means that if you +struggle and things don't go + +well, you don't have any +blemishes on your record. + +Unfortunately, some of the +upperclassmen will tell you as + +pass/no record, you +now, barest pass + +imaginable/ no record. + +Well, I hate to let you know +this, but increasingly I am + +being asked by medical +schools, law schools, + +scholarship providers to reveal +the scores on the + +freshman year. + +So think about that before you +call Hilary in late November + +saying, what do I need +to get a 50? + +I need a 32 on the final? + +OK. + +But Lord help you, you +get a 31 you go down. + +[LAUGHTER] + +PROFESSOR: Upperclassmen get +the luxury of the entire + +alphabet: A, B, C, D, F. + +The final grade composition. + +1/6 for homework-- + +that's the aggregates of the +weekly test scores-- and 1/6 + +for each of the three tests. + +And then the final +is 2/6, or 1/3. + +I didn't want to get into +transcendental numbers, so I + +made it 33 exact, 16.75 exact. + +I could have made it 16.77, I +could have made it 16.81, I + +could have made it +anything I want. + +I'm the professor. + +But I chose 16.75. + +Bottom line here is it's really +dumb to fail the final. + +If you passed the final, you're +pretty much assured + +that we're going +to be favorably + +disposed to passing you. + +But you fail the final +that says two things. + +It says, number one, you don't +have a grasp of the overall + +year, but it also sort of +indicates that you ran out of + +steam partway through the +semester and stopped working. + +It's very bad. + +You get a lot of good advice +from upperclassmen, but + +sometimes-- + +I'd ignore that one that says, +hey, you don't have to do that + +well on the final. + +Anyway, so you have to +get a C level as + +a freshmen or greater. + +And, by the way, we do +not grade on a curve. + +I've seen it in magazines +this last year that + +MIT grades on a curve. + +I don't where they +get that from. + +I don't grade on a curve. + +Your success does not come at +the expense of your neighbor. + +As far as I'm concerned +everybody in this + +class can get an A. + +Again, I'm the professor, +all right? + +So you say, well, how +do you know that 50 + +is the right number? + +Why isn't it 55? + +Why isn't it 75? + +Well, I know. + +I know. + +How do I know? + +Because when we grade, we set up +the point scheme so that if + +the student has the mastery of +the barest level of competency + +of the key concept the +point scheme must + +reflect a passing grade-- + +5 out of 10, 5 out of 9-- + +and you propagate +that through. + +I don't care how much is +written, if it doesn't + +demonstrate basic mastery of +the key concept the point + +scheme must give 4, 3, 2, 0. + +Maybe a 1. + +And so that, if you propagate it +through the whole semester, + +means 50 is a pass. + +There's some wiggle +room there. + +How do I know 49.7 is a +fail and 50 is a pass? + +That's when I call your +recitation instructor. + +[CELL PHONE RINGING] + +PROFESSOR: Let's kill that. + +We're going to get to +that in a second. + +Let's call the recitation +instructor. + +And what happens? + +I ask the recitation instructor, +well, what can you + +tell me about this young lady? + +And, oh, she came to all my +classes, she tried really + +hard, she came to +office hours. + +I don't think the exam is a +proper reflection of her + +understanding. + +I'll listen to that and +maybe we'll promote. + +If, on the other hand, I get the +response, I never saw her, + +didn't come to class. + +I repeatedly reached out to her, +ignored my entreaties, + +she's going down. + +[LAUGHTER] + +PROFESSOR: OK. + +Website. + +This is what the website +looks like. + +There's a number of tabs here. + +The readings are there, the +videos are there archived. + +The schedule-- + +what's going to be coming up. + +So, for example, this is +what's going on today. + +It says what the topic is, +roughly what the readings are. + +I know today you didn't come +to class having read. + +And it's OK, we'll +get through it. + +But from now on I urge you +to do the readings. + +A couple of topics I'm required +to talk about. + +My management requires +me to do so. + +Academic honesty. + +There's a lot of texts here, +but in plain English, this + +says don't cheat! + +You know what this means! + +Now I don't want to hear, +well, in my country, the + +custom is-- + +I don't care what they +do in your country! + +You're in my class, and if +you cheat in my class you + +will pay for it. + +Very simple. + +Accept information of any +kind from others-- + +wrong. + +Represent somebody else's work +as your own-- wrong. + +You know this. + +It was Juvenal, the Roman +politician, said men need not + +so much be instructed +as reminded. + +I'm not telling you anything +you don't already know, but + +I'm going to say it so no one +can say, well, nobody told us + +it wasn't OK to erase our +answers and hand them back in + +for more points. + +I just did. + +All right? + +So if in the unlikely-- but +it happens every so often. + +Maybe every two, three years. + +And people get caught. + +You know why they get caught? + +Because for the first time in +your life you're being taught + +by people who are as +smart as you are. + +[LAUGHTER] + +PROFESSOR: My TAs are +really smart. + +And it never ceases to amaze +me-- somebody succumbs and + +does something dishonest, +and they get caught! + +They get busted! + +And what happens then? + +Then I get angry. + +You know why? + +Because we can't settle +that in my office. + +You can't come and +cry in my office. + +I have to take this episode to a +committee here at MIT called + +the Committee on Discipline. + +It is staffed by faculty, by + +administrators, and by students. + +And the case is brought before +the COD at a hearing and a + +punishment is decided. + +And it can be anything from +suspension to expulsion. + +And of the three categories, +faculty, administrators, + +students, which category do you +think is most severe on + +infringers? + +AUDIENCE: Students. + +PROFESSOR: Your peers. + +You got it. + +You know, because people my age, +old faculty, they'll be + +like, oh, they're just +kids, whatever. + +The students say, no! + +Throw them out! + +[LAUGHTER] + +PROFESSOR: So it's not going to +be me that's going to expel + +you, it's going to +be your peers. + +So don't do it. + +And if you're ever in an exam +and somebody's pressuring you, + +just raise your hand and +ask to be reseated. + +For all I know, the guy next to +you has got a bad case of + +B.O., you just want to move. + +We will not ask any +questions, so take + +yourself out of the situation. + +Conduct yourself +appropriately. + +Classroom behavior. + +Now this is the first lecture, +there's a whole bunch of + +violations in here right now. + +So I'm going to say it now and +we'll fix it for next time. + +We've got 425 seats here, we've +probably got 475 people, + +and there's only one way we can +make this system work and + +we have to observe certain +rules of decorum. + +And I make the rules. + +So if I want to maintain a +fertile learning environment + +I'm going to ask for these +rules to be observed. + +No talking at all. + +No talking. + +Little conversation here, little +conversation here-- + +it disturbs people. + +I don't want any +food or drink. + +No food, no drink. + +One exception is +the professor. + +[LAUGHTER] + +PROFESSOR: Because I do not want +to have my throat get so + +dry that I can't finish talking +my way through the end + +of the class. + +Otherwise, no food or drink and +no disruptive behavior. + +No horseplay or anything +like that. + +And wireless communication +devices must be silenced. + +Cell phone goes off, you get +up, you leave the room. + +That's it. + +AUDIENCE: Is water OK? + +PROFESSOR: If you need water +because it's some kind of a + +health thing, fine. + +But I do not want to see a whole +bunch of people drawing + +on water bottles. + +Don't need it. + +Don't need it. + +You can go 50 minutes without +your little-- + +whatever. + +[LAUGHTER] + +PROFESSOR: You know why? + +I'll tell you why. + +It's not because I'm trying +to be a control freak. + +This is a chemistry class, but +it's chemistry-centered. + +You didn't just come to MIT to +learn some geeky techno stuff. + +You're preparing for a +professional career, and part + +of that is how you behave, how +to act as a professional. + +And you cannot learn behavior +by doing problem sets. + +How do you learn behavior? + +You learn behavior +by observation. + +And how does one +teach behavior? + +By modeling. + +If you're in some high-level +committee meeting and all of a + +sudden your cell phone goes off +and you're scrambling and + +you can't find the damn thing, +it's in the bottom of your + +briefcase, right? + +I can't tell you how +vulgar that is. + +You're in a professional +setting, you commit + +professional suicide. + +And I need to tell you that. + +If you think it's +OK you're wrong. + +So let's get in the habit. + +Disable the damn thing. + +What do you need? + +You're going to call +your stockbroker? + +What's so important right now? + +And on an exam, that thing goes +off I take the exam in + +front of everybody and-- + +[MAKING RIPPING NOISE] + +PROFESSOR: --we introduce a +defect, it's called a tear. + +[LAUGHTER] + +PROFESSOR: And then I put a zero +on it like this, with a + +circle around it. + +It's called a donut. + +[LAUGHTER] + +PROFESSOR: All right. + +Now let's talk about +some lighter + +things, more upbeat things. + +Look, I want you to succeed +in this class. + +Now how are we going +to succeed? + +You go to the listing +in the bulletin + +you'll see this, right? + +And you zoom in here +it says 5-0-7. + +What's this mean? + +Well the 5 is 5 contact hours. + +3 here and 2 with +your recitation. + +The 0 is lab. + +There's no lab with +this class. + +So what's the 7? + +The 7 is the reading, +the homework, + +preparation, et cetera. + +I pledge to you, you give me 7 +hours-- you go to the 5 hours + +contact and 7 hours-- + +you will not just pass this +class, you will flourish in + +this class. + +How do I know this? + +Because I used to chair the +committee on admissions and + +I've read applications. + +I know the quality of individual +in this room. + +You should have seen, there were +11,000 applications piled + +up like this, each dossier like +this, and they just get + +copied down on a four-by-six +card. + +We get here on a Presidents' Day +weekend and we got stacks + +and stacks of the cards. + +We're looking at your whole +academic life is on a + +four-by-six card. + +And I pick that up +and I go, yes. + +Literally at this speed. + +About 45 seconds. + +No. + +[LAUGHTER] + +PROFESSOR: Hell no! + +[LAUGHTER] + +PROFESSOR: That's how I spent +Presidents' Day weekend. + +And so you got through a very +grueling selection process. + +What's the corollary of that? + +Listen carefully to this: +Everybody in this room has the + +intellectual apparatus +to pass 3.091. + +The only people who fail +3.091 are people who + +choose to fail 3.091. + +They choose not to come to +class, they chose not to go to + +recitation, they chose not +to work the homework. + +I don't know why they +make those choices. + +But I guarantee you if you give +me this amount of time, + +you'll do well. + +It's straightforward. + +Number one problem you are going +to face this fall is not + +secondary bonding, it's +time management. + +So I used to call this +strategies for-- + +what did I used to call it? + +I forgot. + +I used to have it something +like, survival strategies. + +But I don't want +you to survive, + +I want you to flourish. + +So I call it recipe +for success. + +There are different venues +for learning. + +OK? + +So lecture, that's here. + +That's my responsibility. + +Recitation, that's Tuesdays +and Thursdays. + +That's my staff. + +Now reading, that's you. + +Homework, that'd be you. + +Weekly quizzes is you, +monthly tests is you, + +final exam is you. + +[LAUGHTER] + +PROFESSOR: What we have +here is a partnership. + +See? + +[LAUGHTER] + +PROFESSOR: So I'll do my +part, you do your part. + +You know, one of the things +beyond the basic learning of + +the chemistry that we're going +to attempt here is a + +transition. + +You are going to change in +ways you can't imagine. + +I want you to think about the +way you are right now, and I'm + +going to ask you to think +about how you feel about + +yourself on the last +day of class. + +You will be amazed, and it's +not because you know a few + +more chemical equations. + +And what one of the things that +I want to see happen and + +to help facilitate is the +transition from student, which + +you are as a high school +graduate, to scholar. + +And the difference between a +student and a scholar is a + +scholar takes ownership of +his or her learning. + +So you're going to take +ownership of it. + +You know, is this +going to be on? + +Are we responsible for this? + +Go back to high school. + +Here you're a scholar. + +You say, how can I learn +more about this? + +That's the difference. + +So I think we've +covered enough. + +I think we don't want to just +have the whole day, welcome to + +MIT, welcome to MIT. + +So what we're going to do is +we'll get into the lecture, + +and in the very brief amount of +time we have left I'm going + +to talk about the beginnings +of chemistry. + +We're going to talk about +taxonomy, classification, + +nomenclature. + +And to help introduce this I'm +going to refer to the writings + +of William Shakespeare. + +We're going to integrate +some humanities here. + +We're going to read from +Romeo and Juliet. + +Maybe there are people here +who were admitted on the + +strength of the performance +in Romeo and Juliet. + +Maybe one of you was Romeo, +one of you was Juliet. + +Maybe one of you did +the lighting. + +Maybe one of you did +the set design. + +Maybe one of you took +the tickets. + +Somehow you were involved, +right? + +Because we're all involved. + +So let's take a look. + +Act 2, Scene 2. + +Romeo: "But soft, what light +through yonder window breaks? + +It is the east"-- + +that's the east. East Campus +is that way, right? + +[LAUGHTER] + +PROFESSOR: "It is the east, and +Juliet is the sun." That + +has nothing to do with +nomenclature. + +Maybe photon emission, but-- + +that's a joke. + +We'll get to it. + +Now Juliet: "O Romeo, Romeo! + +Wherefore art thou Romeo? + +Deny thy father and +refuse thy name. + +Or, if thou wilt not, be but +sworn my love, and I'll no + +longer be a Capulet." +See she's a + +Capulet, he's a Montague. + +You know, the Hatfields +and the McCoys. + +And this is a metaphor. + +It's as old as literature. + +It's about warring factions, +two communities that can't + +stand each other based +on prejudice. + +And then these two youngsters +fall in love, and how love + +triumphs over hatred, +and so on. + +It's powerful stuff and +it's written here. + +Romeo: "Shall I hear more, or +shall I speak at this?" + +Remember, she's up high, he's +doing "Shall I hear more, + +shall I speak at this?" Fellows, +the answer to that + +question is don't speak. + +Don't interrupt her. + +All right. + +So now she goes, "'Tis but thy +name that is my enemy. + +Thou art thyself, though +not a Montague. + +What's Montague? + +It is nor hand, nor foot, nor +arm, nor face, nor any other + +part belonging to a man. + +O, be some other name! + +What's in a name? + +That which we call a rose by any +other word would smell as + +sweet." That's properties, +right? + +"So Romeo would, were he not +Romeo called, retain that dear + +perfection which he owes +without that title. + +Romeo, doff thy name, and for +that name which is no part of + +thee take all myself." + +Beautiful writing. + +400 years ago and it's +just fantastic. + +Well, that's no good. + +That's not the way it +works in science. + +In science we have to agree-- + +[LAUGHTER] + +PROFESSOR: We have to +agree on the name. + +And so this is taken from +Chapter 1 of the text, and + +this is the classification +of matter. + +This is about stuff and the +different forms of stuff. + +Over here we have the simplest +form of stuff, + +which is the element. + +And we're going to start here +in 3.091 and we're going to + +work our way all the way through +this table, starting + +with electronic structure and +how electronic structure + +governs stuff. + +So let's start with +a history lesson. + +We'll start with a +history lesson. + +And the history lesson +goes like this. + +What are the origins +of chemistry? + +The ancient Egyptian hieroglyphs +refer to khemeia, + +which was a chemical process +for embalming the dead. + +You know the Egyptians were very +fixated on the afterlife. + +And the chemists, the chemists +were revered in that society-- + +not like here. + +They were revered in that +society because they knew how + +to prepare the body +for the afterlife. + +Embalming is a chemical +process. + +A few years ago I +was in London. + +I toured the British Museum +and came upon this. + +This is 18 inches tall. + +It's the mummified cat. + +It's a fantastic example +of mummification. + +It's a beautiful-- most people +go zooming right past it. + +They're looking at the +big dinosaurs and + +all that other nonsense. + +But this, this is beautiful. + +Mummified cat. + +And then khemeia expanded to +other chemical processes: + +dying of cloth, glassmaking, +and metals extraction. + +The chemist could take dirt +and turn it into metal. + +Sorcery. + +Some things haven't changed. + +I'm in that tradition: producing +metal from dirt. + +And they were always looking for +an overarching theme, to + +unite the heavens with +the simple elements. + +So the seven known, +naked-to-the-eye, astronomical + +bodies were associated +with the seven + +known chemical elements. + +And you could even talk in +this priestly language. + +So if you wanted to make a +bronze, which is an alloy of + +tin and copper, you could say, +well let's have the confluence + +of Jupiter and Venus. + +It's all there. + +Mercury. + +Why do we call it Mercury? + +Mercury's a metal that's liquid +at room temperature. + +It's fast. Because Mercury is +the planet that moves quickest + +around the sun. + +Very nice. + +So this is what we knew +2,400 years ago. + +We had the seven metals, +carbon, and silicon. + +And the beginning of the shift +from practice to theory, or + +from craft to science, is with +the work of Democritus. + +Democritus, who lived +around 400 BCE. + +Democritus, who was Greek. + +He described the physical +world as consisting of a + +combination of void +plus being. + +Void plus being. + +These are lofty words. + +Listen to this. + +Void, being not some +little equation. + +It's big, big ideas. + +And how did he describe void? + +Void is something that we +would recognize, in his + +language, as akin to what we +recognize to be vacuum. + +And being, he said, was +comprised of an infinity of + +atoms. + +He coined the term "atom." +"Atom" comes from the Greek + +tomoi, which is to slice. + +And then if you put "a" in front +of it as in apolitical + +or amoral, cannot be sliced: +indivisible. + +The atom cannot be sliced, +and so to these atoms he + +attributed these properties. + +They're indivisible +and eternal. + +I mean, this takes you all the +way to E equals m c squared. + +From 400 BCE, and that's all +he had to work with. + +This is brilliant. + +Absolutely brilliant. + +But to show you that things +don't always go in a linear + +fashion for the better, +along comes Aristotle. + +Aristotle, another Greek, and he +decided, nah, we don't need + +all this carbon, sulfur, +and so on. + +He said, we will have four +essences that will describe + +the earthly world. + +Four essences. + +And here are the +four essences. + +Earth, water, air, fire. + +So those are the Aristotelian +essences. + +And there's actually a +fifth essence that + +describes the heavens. + +That's why we say something +is quintessential. + +It's heavenly, it's et cetera. + +So these are the +four essences. + +All right? + +And then it gets even worse +because he has compounds, a + +combination, so you can take +fire plus earth and make dry, + +earth plus water make cold, air +plus water make wet, air + +plus fire make hot. + +This is nuts. + +[LAUGHTER] + +PROFESSOR: And it dominated +science for a long, long time. + +Because we know really earth +is an aggregate. + +It's an aggregate of different +minerals which are compounds. + +Water, as you know, +is a compound H2O. + +Fire is the product +of combustion. + +It doesn't even belong +in this set. + +And air is a solution. + +It's a homogeneous mixture of +nitrogen, oxygen, argon, + +rising levels of carbon dioxide, +sulfur dioxide. + +And if you're next to +an aluminum smelter, + +tetrafluoromethane. + +And so on and so forth. + +And finally this thing +was knocked down. + +So we can look at this chart +and go back to this one and + +say, now we can make +the connections. + +All right. + +Here's the way the elements +looked at the time of the + +American Revolution. + +The alchemists gave us arsenic, +antimony, and bismuth + +in the 12th, 13th, +14th centuries. + +In 13th century India, there +was zinc isolated. + +There's a tall zinc pillar +still standing there. + +Platinum is an American metal. + +It was unknown to +the Europeans. + +It was discovered when the +Spanish came to the Americas. + +Actually, it's kind of ironic +because plata is silver, so + +platina is sort of like a +diminutive of silver, which in + +point of fact is backwards +because silver melts at 962 + +degrees Celsius, platinum +melts at 1768. + +It is nobler than silver. + +It has catalytic properties. + +It is even fashionable in +jewelry now if you know how to + +work with it, because gold melts +at 1063 and platinum + +melts at 1762. + +A lot of jewelers can't +work with platinum. + +It's too high-melting. + +It's a fantastic metal. + +It's an American metal. + +[LAUGHTER] + +PROFESSOR: It really is. + +I mean it's an American metal. + +I didn't make this up. + +It's true. + +And then we see these +other elements. + +Discovered, discovered, +discovered, discovered. + +Now we see modern science. + +So what does it mean, +discovered 1766? + +There was no hydrogen +before 1766? + +They found it? + +No. + +It means that Cavendish isolated +it and documented its + +properties. + +Hence, it was discovered. + +Now I've been cheating here. + +This is actually lined up in +a way that we already know, + +where the story is going to +end with this, with the + +Periodic Table. + +I'm just lying them on the table +in a way that makes it + +possible to anticipate. + +But this was the first table of +elements that is of record, + +and this was by John Dalton, the +English chemist, who put + +these in order of atomic mass. + +They're organized in ascending +order of atomic mass. + +And he also started a system +of chemical symbols. + +And you can see that iron has +an "I" with a circle around + +it, and zinc has a "Z" with +a circle around it. + +And the Swedish chemist +Berzelius said, you know I + +don't think the French are going +to like to use "I" with + +a circle around it for iron, +or Germans aren't + +going to like that. + +We better choose something +a little bit neutral. + +So they chose Latin. + +And that's why iron is "Fe" for +ferrum, and gold is "Au" + +for arum, and so on. + +But this was the +first attempt. + +John Dalton actually +was a polymath. + +He was also working on vision, +human vision, and he suffered + +from an affliction that is +present in about 10% of men, + +which is red-green +color blindness. + +And he did the original work on +red-green color blindness. + +In fact, in some circles it +is known as Daltonism. + +It's the same man, +John Dalton. + +Other classifications. + +Dobereiner in Jena talked +about triads. + +And if you took the atomic mass +of chlorine, added it to + +the atomic massive of iodine +divided by two, you get + +something that's not +too far off the + +atomic mass of bromine. + +Newlands was a musician and +he talked about octaves. + +So if you start here, if this +is a diatonic scale, so this + +is C, D, E, F, G, A, B, C. + +So potassium lies an octave +away from sodium. + +He was ridiculed. + +They said, have you considered +perhaps putting the elements + +in alphabetical order? + +They were cruel. + +Scientists can be very +cruel to new ideas. + +And, in fact, in your book this +is some of Newlands work, + +and you can see to what extent +it helps understand things. + +But the first proper +organization came in 1869 with + +Mendeleyev, and also 1870 with +Lothar Meyer in Tuebingen, the + +Periodic table as we know it. + +And this is the set of +elements that were + +known at the time. + +And this is a page from the +paper in which Mendeleyev + +published the Periodic Table. + +And here's the smoking +gun right here. + +It's right here where he says, +in this new system, in this + +proposed system, there are very +many missing elements. + +Very many missing elements-- + +that was the key. + +Because he knew that even though +arsenic has the atomic + +mass next highest to that of +zinc not to put arsenic under + +aluminum, not to put +it under silicon. + +It had more in common +with phosphorus. + +So he put it under phosphorus, +and so did Meyer. + +But what Mendeleyev did, which +was a first, he said, there + +are missing elements here. + +There is an element that lies +between silicon and tin, and I + +predict what it's +mass will be. + +I predict what it's chemical +formulation will be, how it + +will react with oxygen. + +The predictions. + +And how did he get this? + +Because he used to travel by +train and he would sit in the + +train station on his trunk +playing solitaire. + +And he'd be going down +one suit, and then + +there'd be a gap. + +And he'd go down the other suit +and he could go farther. + +And so the concept of, I know +there should be an eight of + +spades here, but I have +to stop at the nine. + +I've got a seven but there's +something in there-- + +triggered his imagination and +led him to have the courage to + +say, there are elements there +and I will predict their + +properties. + +And when they were discovered +how close he was is shocking. + +Absolutely shocking. + +So we'll get to that next day. + +But before you go I want +to leave you with this. + +This is the portrait +of Mendeleyev that + +you typically see. + +This man on in years, +disheveled, sort of mad + +scientist look. + +Don't remember that. + +Look at this. + +This is Mendeleyev, age 35, when +he proposed the Periodic + +Table of the Elements. + +OK. + +We'll adjourn. + +We'll see you on Friday. \ No newline at end of file diff --git a/vPXTDpXwBs0.txt b/vPXTDpXwBs0.txt new file mode 100644 index 0000000000000000000000000000000000000000..462b01c0e1e7bf69526728cdb0a69c687e631abc --- /dev/null +++ b/vPXTDpXwBs0.txt @@ -0,0 +1,4031 @@ +The following +content is provided + +under a Creative +Commons license. + +Your support will help MIT +OpenCourseWare continue + +to offer high-quality +educational resources for free. + +To make a donation or to +view additional materials + +from hundreds of MIT courses, +visit MIT OpenCourseWare + +at ocw.mit.edu. + +PROFESSOR: All right. + +Good afternoon, everyone. + +Today, we are going +to have two topics. + +In the first half we are going +to discuss visual illusions, + +and in the second +half we are going + +to talk about prosthetic +devices for the blind. + +What I would like to +start with is, again, + +to send around the +attendance sheet, + +so please put your name to it. + +And then, in addition, +I'm going to send + +around some handouts, +one for each person. + +I'm going to hand them +out in both directions. + +Thank you. + +The handouts we're +going to look at, + +I'll refer to them +specifically as we go around. + +And I also will show pretty +much the same handouts, figures + +in the handouts, on the screen. + +All right. + +So for the first half of +the presentation today + +we are going to talk +about visual illusions. + +Now, the main emphasis of +what I'm going to talk about, + +it'll be an attempt +to convey to you what + +kinds of procedures one can use +to get a better sense of why + +we see in illusions what we see. + +Some of these approaches +are strictly behavioral. + +And some of them have involved +experiments carried out + +on a more thorough basis using +electrophysiological procedures + +and so on. + +But those I'm not going +to talk too much about. + +But I will relate +what we can figure out + +through how the +visual system works. + +Now, because of that, there +are hundreds of illusions, + +and I will emphasize +those that allow + +us to think about why +we see what we see. + +Now, one of these +illusory effects + +is the so-called +Hermann grid illusion, + +and that's the one +I'm going to start + +with because it's a +fascinating illusion. + +If you look at +this, what you see + +is that at the intersections +you see sort of smudges. + +And so the big question arose +as to why we see these smudges. + +Now, does everybody +see those smudges? + +If you look at the +handouts, I also + +show you-- pay attention +only to the front page, + +the one on the left, which +says the Hermann grid illusion. + +So if you look at that +either on your handout + +or you look at it +on the screen here, + +you see these smudges at the +intersections, not where you're + +looking at, but in the +smudges other than where + +you're fixating. + +Does everybody +see those smudges? + +OK. + +So the question arose why +we have these smudges. + +And back in the +1960s, an investigator + +came up with a +rather clever idea + +of why we see these smudges. + +And the person who came +up with this theory + +was a fellow called Baumgartner. + +And so what he proposed, +that this illusory effect + +is not directly attributable +to the center-surround + +organization or the receptive +fields or retinal ganglion + +cells. + +So what he proposed is that when +a retinal ganglion cell falls + +in the center like this, there's +more inhibition in the surround + +than when it falls along +not the intersections, + +but along the straight lines. + +And because of that, there's +more inhibition here than here, + +and that's why we +see the smudges. + +Now, that was a very +attractive theory. + +And in fact, it has appeared and +still exists in many textbooks + +that you read about illusions +and about vision in general. + +Now, OK, so here is +the exact description + +that I just made +to tell you this. + +And of course, you would expect +that if this is the case, + +you should also get the smudges +if you'd reverse the contrast. + +And in fact, that is true. + +So here, once again, you see +the smudges, maybe not quite + +as sharp. + +But in this case, +it's whiter smudges, + +whereas in the previous +case, this one, + +you have darker smudges. + +So that kind of fits +with that basic idea. + +But then, subsequently, +people began + +to play around with various +conditions to see when you do + +and when you don't +get the smudge effect + +and to see whether that +would fit with this theory. + +Now, that's the basic tenet +in just about everything + +that psychologists +and neuroscientists + +working in the visual system do. + +They try to critically +examine various hypotheses. + +And doesn't have to +be just illusions, + +it can be a whole +bunch of other things. + +And they do this then by +systematically manipulating + +things in experiments that +can present these things just + +under free viewing +conditions, as I'm doing it + +in terms of these +handouts, or you + +can do it under more +controlled conditions. + +The subjects can look through +a tachistoscope or something + +like that. + +All right. + +So anyway, let's now look +at this in a bit more detail + +and see what's wrong +with this theory. + +Well, first of all, if +you look at this figure, + +what you can see here that +you can see the smudges + +irrespective of the size +of the overall display. + +Now, that's a problem +because, of course, + +the size of the receptive +fields in the retina, + +in their center-surround +arrangement, is constant. + +So if it were the +sharp arrangement + +that we described about the +way the center and the surround + +are activated by +the intersections + +and the non-intersections in +the display, that should not + +apply to different sizes. + +It should only work then +for a particular size + +where you approximate that. + +Now, I will elaborate on that +in more detail in just a minute. + +Now, another bug +that arose here is + +that if you now turn this +display just 45 degrees, + +all right, so that it's a +diamond rather than a square, + +the illusory effect has +declined considerably. + +And then to make this +even more problematic, + +and this appears in your +handout on that backside + +of the first page, +what you can see here + +is that when you make +the lines arranged + +in such a fashion at slight +angles to each other, then + +you don't see the +illusory effect at all. + +Whereas here, we also see it +a little bit less but still + +slightly visible. + +But here it's not +visible at all. + +And you can compare that even +better on the handout there. + +So the question is, +why would that be? + +Well, we give you +another example here. + +If you make serrated +edges-- I don't + +know if the people in the +back can see the serrations. + +Those of you in front +can see the serrations. + +And when you do that, +also you fail to see it. + +And the problem +here, of course, is + +that if you make these +slight changes in the angles + +of the intersecting lines +or you make them serrated, + +the center-surround +antagonism should be the same. + +And yet such a small change +causes the illusory effect + +to disappear. + +So that then, in itself, +questions the Baumgartner + +theory. + +Now, there are several other +factors that enter into this. + +This is a very subtle one. + +If you look at this side, +OK, we have different shades + +for the lines. + +OK? + +On this side, we have the +darkened lines, OK, in front. + +And in this case, they +have them in the back. + +And here you see the illusory +effect, and here you don't. + +And once again, how can that +be if the illusory effect is + +due to the center-surround +antagonism? + +Even more dramatic is when +you do this with colors. + +Here you have, again, the +colored lines in front, + +and here you have +them in the back. + +And here you can see +homonymous shades, all right? + +This is darker yellow and so on. + +But it's the same color +but a little bit darker + +at the intersections. + +So here you get a pretty +good illusory effect. + +But once those white +lines are in front, + +we get very little +effect at all. + +So that then denotes a number +of problems with the theory. + +And then one more fact is that +when you present the stimuli + +at isoluminance, you don't +get an effect at all. + +So that then raised +some serious questions + +about the illusory effect. + +And then a +quantitative study was + +undertaken to see just what +is the layout of the receptive + +fields in this display. + +And so here what we +have is a display. + +This square here is exactly five +degrees from your fixation, OK, + +and you can calculate the number +of midget and parasol cells + +that are activated +by that square area. + +And you can see in total there +are more than 360 cells that + +are being activated +in that little region. + +And here is a display, in this +case, of only the ON cells, + +and you can double +that by having the OFF + +cells in the same location. + +Saying that there's just +no good correspondence + +whatsoever in the +number of ganglion cells + +that are being activated and +how the center-surround is truly + +laid out at a point where +you get a very good smudge + +effect with this illusion. + +So this then, +taken all together, + +raises the issue then if indeed +there's a retina phenomenon, + +why is there no fit here? + +And so it does look +like that it's unlikely + +that this illusion +can be explained + +by the center-surround +antagonism theory. + +So then another +theory was advanced + +claiming that this doesn't +take place in the retina, + +but instead that it takes +place in the cortex. + +And so another theory +that was advanced + +is saying that this happens +in the cortex due to the fact + +that you have these +simple cells-- we talked + +about those before-- that had +these elongated inhibitory, + +supposedly +inhibitory, surrounds. + +And if one calculates this, +that can explain the illusion + +a little bit better, +especially since these cells, + +even at any given point +in the visual cortex, + +come in several different sizes. + +So that's an alternate theory. + +But still, further +research needs + +to be done to be able to verify +whether this theory is more + +valid than the center-surround +theory in the retina, which + +certainly is totally wrong. + +So I think maybe in +another 100 years, + +they're going to drop the +Baumgartner theory out + +from textbooks and general +reviews of illusions + +and vision. + +OK. + +So now I want to show you one +more illusory effect, which + +is a variant of the illusion +that I have just shown you. + +And this one is something that +can drive you nuts, I suppose. + +And that appears on the second +front page, the second sheet, + +I should say, of the handout. + +You can look at it there, +or you can look at it here. + +And you can see this +scintillating effect, + +and therefore it has been +called the scintillating grid + +illusion. + +It was invented by +fellow called Lingelbach. + +All right? + +That's a very strong illusory +effect, very dramatic. + +And whether this +can be explained + +by any particular theory +about the visual cortex + +still remains to be settled. + +Right now I don't think +there's a specific theory that + +can explain this. + +Now, I will now move +on and talk about yet + +another illusory effect, +or actually a set of them, + +that has a much +better explanation. + +This one we don't +have a handout for. + +If you look at +this display here, + +you'll agree that the left and +right bars here are identical, + +right, going in shade +from light to dark. + +All right? + +So now what I'm going to +do here-- what I want to do + +is to present these +two images here. + +I want you to fixate +in the fixation spot, + +and we'll count to about, +I don't know, 20, say. + +Keep fixating. + +1, 2, 3, 4, 5, 6, 7, 8, 9, 10. + +1, 2, 3, 4, 5, 6, 7, 8, 9, 20. + +And then I'm going +to go back here, + +and you can see that this side +is much darker than that one. + +Everybody got that effect? + +AUDIENCE: Yeah. + +PROFESSOR: I'll do it once more. + +Pretty dramatic, huh? + +OK. + +Now I'll tell you +what I'm going to do. + +What I want you to do is to +look at this with one eye. + +OK? + +Don't look at it yet. + +Wait a while. + +Just let your eye get settled. + +You're going to look +at it with one eye. + +And then when I switch over, +I want you to switch eyes. + +OK? + +All right, ready? + +Go ahead now and fixate, +and we'll count to 20 again. + +5, 6, 7, 8, 9, 10. + +1, 2, 3, 4, 5, 6, 7, 8, 9, 20. + +Switch. + +And if you do that, you +don't have an effect. + +OK? + +So what does that prove? + +Well, that obviously +proves-- that's why + +it's nice to do these little, +itty-bitty experiments one can + +do in minutes-- it proves +that this is a retinal effect. + +And the effect is +actually due to adaptation + +that we have talked about, when +was it, a couple of times ago. + +Now, I want to show +you yet another effect + +that has a similar arrangement. + +What I'm going to do here is I'm +going to put this display on. + +And what I'm going +to do here is I'm + +going to turn these +off successively + +as we go around the clock. + +OK? + +And what I want +you to do, again, + +is to fixate here +on the cross, OK, + +and then I'm going +to start running it. + +And what are you going to see? + +A pretty amazing thing +you're going to see. + +What do you see? + +AUDIENCE: [INAUDIBLE]. + +PROFESSOR: Yeah? + +You see a green +spot going around? + +Everybody see that? + +OK. + +So now the big question +comes up, why on earth + +do we see this green spot? + +What is the explanation? + +Well, this again is +a retinal effect. + +And to test this +in more detail, we + +have to go back to what I +told you about color vision. + +And when I told you +about color vision-- + +if you remember we did that +experiment with Gaussians-- + +that if you look at the color +circle, all right, and then + +you adapt to a stimulus here, +which is pretty similar to what + +was on the screen, +then the afterimage + +is on the opposite side cutting +across the color circle. + +So the afterimages that +you see that are in color + +can be perfectly explained +by the color circle. + +If you adapt to this, +this is the afterimage. + +You adapt to this, +this is the afterimage. + +It's always straight across +the center line, center point, + +I should say, where you have the +white center, which perfectly + +explains your afterimage. + +So what I'll do again, I'll +show this to you just once more. + +OK, here we go, ready? + +You can experience it again +just to sort of get a sense. + +It's amazing how +the green circle + +becomes more and more +and more and more vivid. + +Now, one more thing +I'm going to tell + +you is when I turn this +off-- keep fixating-- + +and then you're going to see +a green afterimage, right? + +So it proves that, indeed, +it's the afterimage that + +appears over a period of time +with that rotating circle, + +and it's fully explained +by the color circle. + +All right. + +So now we're going +to move on, and you + +look at yet another +illusory effect. + +If you look at this display, +what do you see here? + +You see a light square +and a dark square, right? + +Everybody see that? + +Now, what if I told you +that what you're seeing + +is a total misconception? + +So I'll tell you +what I'm going to do. + +I'm going to leave these two +squares exactly as they are, + +but I'm going to +change the background. + +Ready? + +What's the difference here? + +The difference is that now the +background is uniform, right? + +And you can see these +two squares are indeed + +identical in contrast, right? + +But now if I go back +to the previous one, + +if you look at it +more carefully you + +can see this goes +from light to dark. + +Of course, the projector +makes this look bluish. + +It shouldn't be, but that's OK. + +And it's a gradual shift +in the illumination level + +that fools you to think that +one is light, the other is dark. + +And that has to do +heavily with the fact + +that the receptive fields +of cells in the retina + +have center-surround +organization, + +and they're sensitive to +local contrast differences. + +That's their make-up. + +And so until I +point it out to you, + +can't even tell that +this is a gradual shift. + +And if it did not +change in color, + +it would be harder to tell. + +And it has to do with +the fact that you're + +making local comparisons. + +And because of that, to +make a distant comparison + +you are inaccurate about it. + +So this illusory effect, +again, can be readily explained + +on the basis of what we know +about the center-surround + +organization of receptive +fields in the retina. + +OK. + +Now, if you look at the +same thing in color, which + +doesn't come up too well here +because of the projector, + +but still you can tell that +these are not the same color, + +OK, again because of +the gradual shift, + +color shift, in the background. + +But exactly identical they +are, as they had been before. + +So this works not +only for contrast, + +but it also works for color. + +Now, some illusory effects don't +work for color and some do. + +All right. + +So now yet another +related effect + +that I'm sure some +of you have seen + +before is if you +look at this circle, + +we agree that it's +uniform in color. + +Now, if I cover half of it with +dark and the other with light, + +it still looks pretty the same. + +Maybe it's a little +darker here than here. + +But then if I put a partition +here, as you can see here, + +then this side definitely +looks darker than that side. + +OK? + +So this, again, looks +at contrast effects, + +and we'll talk about these +contrasts in just a bit + +with more detail. + +Next, let me turn to +another illusory effect + +that you can see in many, +many textbooks, which + +is called the +wallpaper illusion. + +If you look at this-- +I'll come to it + +in a second in your display, +where it will appear + +on the back of the second +page-- what you see here, + +it looks like that these +are not parallel lines here. + +I shouldn't say +lines, but parallel + +black and white squares. + +It looks like that they're going +like back and forth like that, + +OK, and it's quite dramatic. + +And so now we can ask the +question, how can we see this? + +What is this due to? + +It could be due to the +way they're aligned. + +It could be due to +the fact that there + +is space between +them, that gray space. + +And so one can do +experiments like the one + +you have on your +next page there. + +Let me first-- I will +prove that, indeed, we + +have parallel lines here. + +These are fully parallel lines, +and they go back and forth. + +To convince you, you can see +that the lines are identical, + +and yet they do +not look parallel + +at all because of +this illusory effect. + +OK. + +So now what we can do is we can +fiddle around with this a bit. + +Now, that's the kind of +thing you guys would probably + +enjoy doing yourselves-- +look at various illusions + +and start playing +around with them. + +This is an example. + +This is a basic +wallpaper illusion. + +And now you turn this into +an equal checkerboard, OK? + +And if you keep the +lines in between, + +and you get no +effect whatsoever. + +And then here we +eliminate those gray bars, + +and the illusory effect +is greatly reduced. + +So consequently, +the illusory effect + +has to do with both +the fact that you + +have space between the +alternating black and white + +bars, meaning these +gray lines here, + +and that you have them offset. + +So when it's not offset, +you don't get it. + +And when you don't have +the bars, you don't get it. + +So these two factors +play an important role + +in giving rise to +the illusory effect. + +Now, what we also can examine +is what happens at isoluminance. + +And in this case, once +again, what happens + +is that the illusory +effect is still there, + +but it is reduced under +isoluminant conditions. + +And this is not the +isoluminant actually + +because of the projector. + +But when it's +perfectly isoluminant, + +then the illusory +effect is largely lost. + +All right. + +So now we have a variant of this +illusion which is fascinating. + +And this one I will show +you on the next page, OK? + +And if you look at +just this display, + +and you are convinced that we +have lines that are alternating + +that are filtered +back and forth, right? + +Well, is that really true? + +Well, it turns out if you +take a bunch of red lines here + +that are perfectly +parallel, OK, and then you + +superimpose those +on the display, + +you can see that actually +the display is parallel. + +OK? + +The reason it +doesn't look parallel + +is due to the way these +individual little pieces + +that you're not even +conscious of are arranged. + +So let's look at +that in more detail. + +Let me add here one more thing. + +At isoluminance, you get +practically no effect. + +So these illusions, this +one and the previous one, + +heavily depend on +contrast differences. + +OK. + +So here we go. + +Here's the basic +illusory effect. + +And the way this was constructed +is shown enlarged on top. + +Alternate lines have +1, 2, 1, 2, 1, 2, 1. + +OK? + +What you have in the top line, +and the third, and so on, + +you have it in this orientation. + +Here you have them reversed. + +And that vague cue +is what somehow + +provides the illusory +effect for you. + +Now, if you make all +the lines similar, + +OK, in other words don't +reverse the alternate lines, + +then what you see +here is actually + +the bars are all +tilted slightly upward. + +OK? + +And because of that, +the illusory effect + +is not as dramatic as this +one, but you still have it. + +All right? + +So what then you +can do with this + +is to enlarge on this +effect as shown here. + +It looks like that you have +somehow a very unequal set + +of lines, as a result +of which you do not + +have a bunch of +clear-cut squares. + +And if you, again, superimpose +true parallel lines through it, + +you see that they are +actually parallel. + +All right. + +So that then explains +that illusory effect + +in terms of how we somehow +integrate information of shape + +that we are not even +aware of to have + +a perception of a whole thing. + +Now, that's not much +of an explanation. + +It doesn't tell you what +neurons are involved + +or anything like that. + +But it gives you +a general concept + +of how that illusory +effect is created. + +Now we come to yet another +fascinating illusory effect, + +and that one is in the next +few pages in the handout. + +So if you take the +backside of page 3, + +you will see this +illusory effect here. + +Does everybody see that? + +Now, this illusory effect is +one which gives you a sense + +that you have a whole +bunch of swirls. + +All right? + +Does everybody see those swirls? + +Instead of seeing 1, 2, 3, 4 +circles, you see some swirls. + +And you say what on earth +is giving us that sensation? + +So what you want to do then +is to look at it analytically. + +And what you see +here is you have + +alternating black and white +squares, first of all. + +And you say, well, +is alternating + +black and white squares +the central point? + +But then if you look +at it more closely, + +you can see this is-- I +don't know how they came up + +with this one-- what you see +here, if you look at each + +of these, that there's a +gradual shift as you go + +around the circle in the +orientation of the square. + +So this square +becomes progressively, + +very slowly, more rotated. + +OK? + +And that goes around +the clock, and that's + +true for every one +of those circles. + +And you can say, well, is it due +to the black and white squares? + +Is it due to the change in +the orientation of the squares + +that you're not even aware of? + +Or what? + +So what kind of +experiment do you + +do to check this out, to come +up with some understanding? + +What kind of game can you play? + +Well, the first +game you can play, + +so you can say, +well, let's eliminate + +these slight changes +in orientation. + +OK? + +And so what you can do instead, +as shown on the next page, + +is that you have a +bunch of circles, + +black and white circles, +which are all the same. + +And as you can see +here, there's no swirls. + +You have four +circles, very clear. + +So therefore, +obviously, the squares, + +changing their orientation in +a subtle fashion going around + +in the clock, is very +important in introducing + +this illusory effect. + +Well, then you can say, +OK, but is that all of it? + +And so what we can do here, +as shown on the next page, + +is we can maintain +the orientation shift, + +but we can make them all the +same contrast, as we have here. + +And when you do that, you have +have a rather weak illusory + +effect. + +There's still a little bit left +maybe, but it's kind of weak. + +And then if you instead +make it isoluminant, + +you get some in-between effect. + +So on the basis of +that, we can conclude + +that very important +in this display + +is that you have a gradual +shift in the orientations + +of these squares. + +And that, in turn, suggests that +somehow the way these squares + +activate orientation +selective cells in V1 + +plays an important +role in giving rise + +to this strange illusory effect. + +OK. + +So now what we +are going to do is + +to look at yet another +illusory effect, which + +has a different +source, and that one + +is the famous +Muller-Lyer illusion. + +The fact is that +these two bars here + +are identical in size-- do I +have the picture-- like that. + +OK? + +But when you put these inducing +elements, as we will call them, + +OK, on there, you'll swear +that this one is longer + +than this one is. + +OK? + +So now we can ask the question, +what kind of manipulations + +can we undertake to see +what that is all about? + +And let me come back +to that in a minute. + +So what you can +do here is to make + +the inducing elements and +the bars different in color + +or in contrast, and you still +get a strong illusory effect. + +OK? + +So making them +isoluminant or making them + +opposite in contrast does +not eliminate this illusion. + +So the theory that +somebody has come up with + +is shown here, which +I'm not sure I buy, + +but that's +nevertheless a theory, + +it claims that the +brain interprets + +these two displays as +differences in depth, + +as if here we had a protruding +edge in a building inside + +or a receding edge +as shown here. + +And that difference that +we almost unconsciously, + +if you will, interpret as +being in different depths + +is what gives rise +to the illusion + +according to this theory. + +Of course, there's a +simpler theory simply saying + +that we just integrate these +two bits of information. + +All right. + +So now we can ask the question, +if you have illusory effects + +of this sort, is this something +that really takes place higher + +up in the brain, or does it take +place in the retina where we + +cannot separate these +inducing and testing elements? + +Well, the way you +can do this-- I'm + +going to show you +another illusion which + +is similar to this. + +Here we have the so-called +Ebbinghaus illusion. + +This is a very similar +kind of illusion. + +This is a test element +and an inducing element. + +The test element here +are these two circles, + +and you swear that +this one is a smaller + +circle than that one is, right? + +And we have a bunch +of small circles, + +and here we have bunch +of large circles. + +So now we can ask, +well, is this something + +that takes place in +the retina or what? + +So what kind of +experiment can you do? + +Well, the experiment +that you can do + +is to present these +displays interocularly. + +What does that mean? + +What that means is +that you present this + +to the left eye and +this to the right eye. + +And you present +this device that's + +used by psychologists +for this kind of thing. + +It's called a tachistoscope. + +You look through it. + +It can present things +separately through the two eyes, + +and you can flash +them on briefly + +so you don't get any +binocular rivalry. + +And when you do that, then +you can systematically + +vary the size of +these to make sure + +that you can get a +quantitative measure of it. + +And when you do that, you +find that the illusory effect + +is just as good under +interocular conditions + +as it is under binocular +viewing conditions. + +Because of this +then-- this has been + +done with many +kinds of illusions + +including the Muller-Lyer one. + +And when you do that, +you show, in essence, + +that this is an effect +that takes place + +most likely in the +cortex, certainly + +not in the retina or the +lateral geniculate nucleus. + +It takes place someplace +where the images + +from the left and +two eyes converge. + +All right. + +So now yet another +set of illusions + +that I want to show you. + +I think that these +illusory effects are done. + +You can take this home and enjoy +it or show it to your friends. + +Now I'm going to show +you a set of just two + +kinds of motion illusions. + +OK, here's the first one. + +I want you to look +at the screen, + +and I'm going to flash +something on briefly, + +and I'm going to +do it repeatedly. + +Ready? + +What do you see? + +Do you see something moving? + +A very brief sense of +motion that you see. + +This twirls a little bit. + +And this is called +the snake illusion, + +which is really curious. + +This has, again, appeared in +quite a number of textbooks, + +and we do not have a really +good explanation for it. + +But we have another one, +which I think is related. + +OK. + +So what I'm going +to do here, this + +is called the +waterfall illusion. + +So what we are +going to do here is + +I'm going to set this in motion. + +In this case, I don't +want you to fixate. + +What I want you +to do is just keep + +looking at it in various places. + +You can look here, here, +here, and here, and so on. + +OK? + +And I'm going to let +it run for a while, + +and then I'm going to stop it. + +OK? + +And I want you to tell me +what is your aftereffect. + +Ready? + +OK. + +I'm about to stop it. + +Are you ready? + +Pay close attention +to what you're + +going to perceive once it stops. + +Anybody see what happened? + +What did you see? + +AUDIENCE: [INAUDIBLE]. + +PROFESSOR: You see the water +running up here, right? + +OK. + +I'll do it once more so +you can appreciate it. + +Pretty nice, huh? + +OK. + +So this illusory effect is one +that also occurs interocularly. + +And it has been shown that +when you record from area MT, + +we talked about the fact that +area MT is a region where cells + +respond selectively to +direction of motion. + +Well, people have +shown that if you, + +for an extended period of time, +a minute maybe or whatever, + +you stimulate a cell in MT +with this kind of a display, + +then after you stop it, OK, the +cells with the opposite sense + +of motion will +discharge some, which + +then is attributable to the +upward sensation that you have. + +So it's clear enough +that this is something + +that does take place +predominantly by virtue + +of direction-selective +cells and, probably, + +by direction-selective +cells in area MT. + +All right. + +So then what we are +going to do here + +is we're going to look +at some other limitations + +and ambiguities in perception. + +And in particular, +we're going to examine + +some figure/ground +relationships. + +The first one I'm going +to show you is this one. + +If you look at these two +diagonals, OK, a and b, + +they certainly look very, +very different, don't they? + +OK? + +One looks shorter and +a different angle. + +But now if I eliminate the +trapezoid in the surround, + +you can see that they're +actually identical. + +OK? + +I'll show it to you again. + +Pretty dramatic. + +So that's an interesting +illusory effect. + +And it's clear enough +that this is something + +that takes place in +higher cortical areas. + +Yet another one here that +I'm going to show you also + +has something to do with +figure/ground relationships, + +which has been +extensively studied, + +especially by Gestalt +psychologists. + +And I spoke about this a +little bit the last time. + +What you see here is a bunch +of vases, so to speak, right? + +That's good enough. + +So what I'm going +to do now, I'm going + +to show you another +set of vases. + +Are you ready? + +There is another set of vases. + +Everybody see the vases? + +Now, what if I tell +you that there's + +much more to this +than just vases? + +So if you look really +closely, you're + +going to see +something else there. + +What else do you see there? + +AUDIENCE: Faces. + +PROFESSOR: Oh, OK, two faces, +two guys facing each other. + +Now, if I change the relative +number of elements in here, + +which changes the +figure/ground relationships, + +you get a different effect. + +Here you have-- +predominantly you + +see the faces rather +than the vases. + +OK? + +And that's a cute +way of putting it. + +I see the faces, not the vases. + +And then you switch +it, and you say, + +I see the vases, not the faces. + +All right? + +So that then is a way you +can play around, again, + +with various illusory +effects by fiddling around + +on your computer and +creating things like that. + +OK. + +Now, yet another +strange effect is + +where you can have +difficulty telling what's + +what is this kind of a display. + +You say, well, what's +happening here? + +Are arrows pointing +to the right, + +or are they pointing +to the left? + +And that reminds one of a +fellow called Yogi Berra. + +How many of you have +ever heard of Yogi Berra? + +Oh, my goodness, very good. + +OK. + +So he was a famous catcher for +the New York Yankees, right? + +Well, he was a very +interesting guy, + +had all kinds of +interesting statements. + +And one of those many curious +statements, one of them + +is-- it doesn't relate to this. + +It just comes into my head. + +"It isn't over until it's over." + +That's one of his, OK? + +This one here +that's relevant is, + +"When you get to a fork +in the road, take it." + +Yeah? + +And that's a Yogi Berra quote. + +And so what we have +here is a sign that you + +come to a fork in the road, and +you have to decide to take it. + +What are you going to do? + +Are you going to go this way, +or are you going to go that way? + +So that's a kind of +game you can play + +with this kind of strange +effect that you can create + +that is confusing your +ability to organize + +your visual percepts. + +Another famous one, maybe +not that famous, actually. + +Maybe some of you +have seen this. + +This, again, has appeared many, +many years ago in The New. + +Yorker. + +It says, "I'm turning +into my mother." + +Now, keep looking +at it and tell me, + +why do you think that that +comment is being made? + +What we have here, a young woman +looking at another young woman, + +right? + +But now if you keep looking +at this display, look. + +This is a nose here, +and this is a mouth. + +You see an old lady now? + +OK. + +You played around with this, it +gives you a confusing percept. + +And ultimately, you can +see the young person + +looking that way or an old +lady looking the other way. + +I mean looking not +backwards but across. + +And that's why this +statement says, + +"I'm turning into my mother." + +So the essence here +is that playing around + +with these kinds of illusory +effect is a lot of fun, + +and we all very much enjoy +looking at illusions. + +And some of us like to +play around with them + +to try to figure out what their +existence is for the reasons. + +Now, I want to +show you one more, + +which I think is very +appropriate at this time. + +This is the famous +Greek key motif. + +Everybody's seen +this, I presume. + +Does everybody know where +this is displayed, actually, + +at several places? + +In the Senate. + +OK? + +Whenever you have a picture +of the Senate Building, + +you will see this. + +All right? + +Now, that's a little +bit amusing, actually, + +if you think about it. + +So this has become +symbolic of democracy. + +And considering just what +happened most recently, + +you could almost +say that, perhaps, + +what's happening here is that +you cannot tell whether we see + +this guy or this guy +here going around. + +OK? + +And one of them you could say, +oh, these are the Democrats. + +These are the Republicans. + +And you have sort of a conflict +as to which ones you see. + +All right? + +And that is, in a way, symbolic +of what's going on today. + +But to educate you +a little bit, which + +I suspect probably most of +you know already anyway, + +this Greek key motif +actually has its source + +in the so-called +myth of the Labyrinth + +that had imprisoned +the Minotaur. + +Who knows who the Minotaur is? + +Oh, very good. + +Many of you do. + +All right. + +So the Minotaur +was a creature that + +was half bull and half human. + +All right? + +And what happened, according to +this myth-- and let me tell you + +it's a myth, and it's +a bit of risque thing. + +There was a king +called King Minos + +whose wife Pasiphae-- +Pasiphae, I'm not sure + +how you pronounce it properly-- +is the one who had intercourse + +with a bull and +gave birth-- sorry, + +had intercourse with a bull. + +And as a result of +that, gave birth + +to the Minotaur, which was a +half-bull, half-human monster, + +if you will. + +All right? + +And that became so +threatening and so irritating, + +I guess, to King +Minos that he asked + +one of his subjugates, Daedalus, +to create a maze, a huge maze, + +and he put the Minotaur in it. + +So it was such a maze +that the Minotaur just + +couldn't get out of it. + +All right? + +But then things got +progressively worse, + +and King Minos decided +that he had better + +get this Minotaur killed. + +And so he asked a person +whose name is Theseus, OK, + +to go into the maze +and kill the Minotaur. + +Now, the king also +had another offspring + +whose name is Ariadne-- +nice name, Ariadne. + +And she said to Theseus that +if you take a ball of thread + +and you walk through +the maze, once you + +do what you have to do, you +can follow the thread back, + +and that way you can +get out of the maze. + +So that's what Theseus +did, and then he + +went on and killed the Minotaur. + +Now, the story didn't end +there because somehow, + +for reasons I'm not sure I +know the details anymore, + +King Minos had a fall +out with Daedalus, + +and he jailed Daedalus +and his son Icarus. + +And while they +were in jail, they + +tried to figure out +how they could escape. + +And so Daedalus +fashioned a pair of wings + +made out of bird's feathers and +wax, and then put it on Icarus. + +And then Icarus, by +doing this, he could fly. + +OK? + +And then he flew and +escaped from the prison. + +But unfortunately, he +flew fairly high up + +where the sun was very hot. + +That melted the wax, and +Icarus, sadly, fell to his death + +as a result. + +So that's quite the story. + +And that's something that +obviously some of you + +already know. + +And those of you who +don't, you will probably + +remember, as so many Greek +myths are just fascinating, + +ancient, old stories. + +All right. + +So then here is actually +a reconstruction + +of the kill of the +Minotaur by Theseus. + +And this is actually a +sculpture that exists in Greece. + +Pretty nice, huh? + +OK. + +Now, the last confusing image +that I wanted to show you + +is this one that had appeared-- +I think this appeared also + +in The New Yorker, +but I'm not 100% sure. + +What you have here +is a confusion-- + +do we have three +or two prongs here? + +And the reason I show +this sometimes in class + +is because in our department +when it was originally + +formed by Hans-Lukas +Teuber, he created + +what is called three prongs. + +OK? + +And then it became sort +of an issue as to, well, + +what are the three prongs? + +Are there two prongs? + +Are there three prongs? + +Who belongs into which prong? + +And so somebody came +up with this picture + +that was put up as a joke +in the department when + +the department was still in +one of the old buildings that + +doesn't even exist anymore. + +All right. + +So that then brings me to the +end of the illusory effects + +that I thought we'd +talk about briefly. + +And I will now move on and +talk about visual prosthesis. + +All right. + +Now, as far as +prosthetics are concerned, + +you're going to hear quite a +bit about that from Chris Brown + +because in audition, an auditory +prosthetic device, the cochlear + +implant, has become +an incredible success. + +There are well over 50,000 +people in the country now + +who have a prosthetic +device like that + +that enables them to +hear, to converse. + +It's really incredible. + +Unfortunately, when it +comes to visual prostheses, + +we have nothing +comparable at this stage. + +It's a much needed device that +will take many, many, many more + +years to create. + +But I thought I'd give you +sort of a crude sense of how + +that kind of work +progresses because there are + +many laboratories that +are trying to come up + +with something that will provide +an ability for people to see. + +Now, I can tell you +that in the world + +there are more than 40 +million people who are blind. + +In the United States, there are +more than a million individuals + +who are blind. + +So because of that-- +that's a huge number-- + +it, of course, is extremely +desirable to come up + +with some device +to do this for you. + +Now, this is a very, +very long history, + +and people have tried +all sorts of things. + +One of those is to try to induce +the ability to see something + +in the world that you +normally see with your eye + +by putting it through +some other sense. + +Now, a simple example +of that is Braille. + +All right? + +Everybody knows what +Braille is, right? + +That's you can use your +hand to feel something that + +has protruding +elements in it that + +can be shown in +terms of letters. + +And so as you get into an +elevator and you can't see, + +you can feel it, and then +you can push the right button + +to get to the right floor. + +OK? + +Now, that's one way +it has been done. + +Another approach had been +to present stimulation + +to your somatosensory system, +either by putting something + +on your back or putting +something on your fingertip, + +that an image would be converted +into actually activating + +your somatosensory +system that would + +be equivalent to something that +you would perceive if you could + +see. + +So that's the basic thing. + +And a tremendous +amount of effort + +has been going on to try to +come up with something to create + +a workable prosthetic +device for the blind. + +Now, there's a lot +of disagreement + +as to where such a device +should be placed in the body + +and also a lot of debate +of what kind of procedures + +should be used. + +Now, some people +advocate that it + +should be done on the retina. + +Some people advocate +it should be + +done in the lateral +geniculate nucleus. + +Actually, some +work is being done + +at Harvard trying to +come up with something + +for the lateral +geniculate nucleus. + +And there's some +people who think + +it would be best to do +it in the visual cortex. + +So let me sort of go into +this in a bit more detail. + +And let me, first of all, +raise the question of, + +what kinds of devices, and +what kinds of necessities + +do we have for converting +vision into something + +that enables blind +people to see? + +Well, first of all, +it's very important + +to be able to see some basic +patterns, very important to see + +motion, and very +important, often ignored, + +is that you got to be +able to see something + +in the third dimension, +because a person who is blind, + +he should be able to +walk in the world. + +And if you're going +to walk around, + +you should be able to see +where things are in depth. + +So those are the +basic requirements. + +You're certainly not required +to process color information. + +So that's not important. + +And there are several other +things that are not important. + +But these are the three +most important ones + +that you would like to +have if you are going + +to create a prosthetics +device for the blind. + +Now, then the next +question is, how are we + +going to deal with +this, and what kinds + +of issues and problems +are we going to deal with? + +First of all, the big issue is +what kind of prosthetic device + +should we use. + +One of those that +I've already mentioned + +is to try to convert +visual impressions + +into other modalities such +as your somatosensory system. + +All right? + +The other is to create some +sort of stimulating device, + +which there are various kinds. + +But one of those +would be, for example, + +to put a bunch of +electrodes into the brain, + +or into the retina, or whatever, +and then selectively stimulate + +through this series +of electrodes + +to mimic the visual field. + +Now, the other one, +and it is a big issue, + +what brain areas +should be considered? + +And because we're at +an early stage in this, + +I think it is +desirable for people + +to pursue just about any +area they think might work. + +Now, the problem with +a retinal implant-- + +there are two problems with it. + +One is the retina is extremely +small, and very confined, + +and has these millions of +receptors and ganglion cells, + +and how can you +selectively activate them? + +Now, the biggest +problem, though, + +is that in most blind +people, the retina + +becomes non-functional. + +And even worse, it degenerates +in a relatively short time + +so that it no longer is useful +for electrical stimulation + +or for whatever +kind of stimulation + +you wish to engage in. + +So because of that, +some people have + +moved on to the lateral +geniculate nucleus. + +That area has some problems +because it's deep in the brain, + +and it's quite small. + +OK? + +And also, it tends to +degenerate over time, + +although it takes it a lot +longer than the degeneration + +of the retina. + +Thirdly, people have considered +stimulating the visual cortex, + +and that's what +I'm going to talk + +about in a bit more +detail just now. + +But the last thing that's very +important here-- I think it's + +the last thing. + +Yeah, just let me go back. + +Ah, sorry. + +The third big issue +is, can you create + +a device that has longevity? + +As soon as you put +something into the brain + +and into the eye, +there's going to be + +some sort of adverse +reaction that + +may kill the cells at +the tip of the electrodes + +or something like that. + +So all kinds of +approaches have been + +created to try to increase +the longevity of the device. + +Now, I'm going to +next look at what + +happens in the +visual cortex, which + +is a promising, at least I +think it is, a promising site + +where you could electrically +stimulate and use + +that to create a +visual impression. + +All right. + +If you do that-- here +is a monkey brain. + +The monkey is very +well suited for this + +because, as I have mentioned +before, the posterior + +part of the cortex-- see, this +is area V1-- is lissencephalic. + +And so it's relatively easy +to place accurately electrodes + +into it. + +OK? + +So then if what you do +here-- here, just a reminder, + +is the central sulcus. + +Here's the lunate sulcus. + +And here, of course, is area V1. + +If you now take the +contralateral hemifield, + +that projects into this region. + +OK? + +This is shown out to +about five degrees. + +That will go to +around here like that. + +OK? + +So now the next big +question that, initially, + +had been done +actually in humans, + +what do you see when you +insert a microelectrode + +into the brain-- as I say, this +was done on humans initially-- + +and you electrically stimulate? + +What do you see? + +And this work was done by +Brindley many years ago. + +And he discovered that +when you electrically + +stimulate in the human primary +visual cortex, what you get + +is a small, star-like image. + +All right? + +So that's what he found. + +And so that then triggered +a great deal of research, + +including work in +monkeys, to determine + +what could be done to create +a prosthetic device that + +might just work. + +So the first step +then was to try + +to determine what +happens when you + +put a microelectrode in here. + +This is, by the way, the +layout of the visual field + +in the posterior cortex +with much more area devoted + +to the fovea than into the +periphery because, of course, + +there's a much higher packing +density of receptor cells + +as well as retinal +ganglion cells in the fovea + +representation than further out. + +In the cortex, the thickness +of the gray matter is constant. + +It's about roughly +2 millimeters thick. + +And the frequency, spatial +frequency of the cells, + +is pretty constant as well. + +So therefore, you need +to allocate more space + +to the incoming huge +number of retinal ganglion + +cells projected +to the geniculate + +and then to the cortex +than for the periphery. + +And that's why +you have this kind + +of a layout of much +more space allocated + +to the central than +to peripheral vision. + +So that's a very +important factor + +in considering how to +create a prosthetic device. + +So now the first step in +doing this kind of stuff, + +if you're going to do serious +experiments on monkeys, + +is to determine, +what does the monkey + +see when you electrically +stimulate the visual cortex? + +And so the experiment +that's been done here + +is one in which a +monkey has been trained + +to make an eye movement to the +bigger of two visual stimuli + +or the brighter of two stimuli. + +In this case, we have +two visual targets. + +By the way, one +of these is going + +to appear where the receptive +field is of the cells + +that you're going to stimulate +in the visual cortex. + +So then you may sometimes make +this one brighter, this one + +brighter. + +And the monkey makes +a saccade to it, + +and he gets a drop of +apple juice for reward. + +And then you can systematically +vary the relative size + +of the two stimuli to see what +kind of a function you get. + +And the same thing you can do +for the relative brightness + +of it. + +And then on some trials +interspersed with those trials, + +you present +[INAUDIBLE] stimulation + +with the visual +target and see which + +one does the monkey go to. + +And then you +systematically vary, + +as I said, the brightness or +the size of those stimuli. + +OK? + +We vary the contrast in +this case, and in this case, + +we vary the size. + +OK? + +So that's the basic experiment. + +And if you do that +systematically, + +you can tell exactly what +the size and the contrast + +is of the visual +stimulus created + +by electrical stimulation. + +If you do that-- +here's an example. + +When you present +two visual stimuli + +and you vary the percent +contrast difference, all right, + +of the two stimuli, you can see +that it crosses over, indeed, + +when they're identical. + +So that tells you that +this system works. + +It says these are identical. + +And the same thing is +true for the size series. + +So this way then, if you +do the same experiment + +with electrical stimulation, +you can find out + +where this 50% +crossover point is. + +This is for contrast, +and this is for size. + +So then you can establish +this with slightly different + +locations in the visual field. + +And if you do that +overall, you come up + +with a summary +statement, which says + +that when you use currents +between 20 and 120 microamps, + +OK, at eccentricities between 2 +and 1/2 and 3 and 1/2 degrees, + +the contrast of the visual +percept created in monkeys + +is 6% to 12%, and the size +is between 15 and 20 minutes + +of visual angle. + +Now, that's quite +small fortunately. + +So it's a local, little +spot, like a star-like image. + +Now, what do we mean +by 6% to 12% contrast? + +So let me tell you +this, that that's + +a useful thing for +you to memorize. + +We talk about percent contrast. + +What you do is you +measure, for example, + +in candelas per square +meter, what the contrast is + +of this and what is the +contest of the background. + +Then you subtract one +from the other, divide it + +by the sum of the two, +and you multiply by 100. + +So when you do that, this +is roughly 8% contrast. + +This is roughly 75% contrast. + +So it gives you a sense +of what contrast means. + +All right? + +So what that means, in essence, +that the visual stimulus + +created by the +electrical stimulation + +is fairly low contrast. + +All right. + +So now the next +important factor, + +once one knows what +the visual percept is + +that is created by electrical +stimulation in the monkey, + +the next thing is to +ask the question, well, + +what kind of electrode array +should one put together? + +All right. + +Well, the big issue +here has to do + +with the so-called +magnification factor + +that I just talked about. + +So let's look at +this analytically. + +First of all, I +already mentioned this. + +We have a very high packing +density of photoreceptors + +in the fovea and much +lower density further out. + +And so what you have +is that this plate + +goes through the optic nerve +up to the visual cortex + +to the lateral +geniculate nucleus. + +So that's the basic +arrangement, meaning + +that there are many, many +more retinal ganglion + +cells per unit area that +impinge on the visual cortex + +near the fovea than +in the periphery. + +So then to examine this, here +we have, again, another picture. + +It's the geniculate again. + +Here's the fact that the cortex +is constant in thickness. + +And here's the layout of the +visual field on the posterior + +cortex with more area +allocated to the fovea + +than to-- excuse me, +than to periphery. + +All right. + +So now I've shown you a +variant of this before. + +If you present an arrow +across the visual field here, + +this is the impression made +with much more activation + +in central vision than +in peripheral vision. + +I mean, you don't have +to worry about that. + +That simply tells you, as +we had discussed before, + +that the images +created depend heavily + +on where you stimulate +in the visual field. + +OK. + +So now to look at +this quantitatively, + +so we put a bunch of dots +up in the visual field. + +This is in the +central four degrees, + +and this is the +actual activation + +in the visual cortex. + +OK? + +Meaning that in the fovea, +we have two elements here, + +this one and this one, here +and here, that they take up + +a lot of space, whereas +in the periphery, + +OK, they're very +close to each other. + +That's due to the so-called +magnification factor. + +And so one of the basic +rules is that we've + +got to be able to stimulate +the visual cortex taking + +into account the +magnification factor. + +So if you have this kind +of spatial arrangement, + +if we then were to put +a bunch of electrodes + +in like this, which we will +call proportional electrodes, + +then if you +stimulated all those, + +you would get a similar +square with one proviso, + +namely that the little dots +would be smaller in the fovea, + +obviously, than +in the periphery. + +So then if you have this kind +of arrangement, what you can do + +is you can take a camera that +has a fixed number of elements, + +and each of those +elements you hook up + +to one of the electrodes. + +If you put the word +"fiat lux" there, + +this is what you hypothetically +would create, like that. + +OK? + +That's what it would look like. + +So in contrast with +this arrangement, + +if we were to use +an electrode array, + +which you can readily buy-- you +cannot buy proportional arrays. + +You have to somehow +create them yourself. + +But if you buy a fixed +array, which the elements are + +equidistant, then if +you stimulated all those + +you would get a butterfly +image, butterfly image. + +I will show a movie +of that as well. + +And that means that if you do +that same conversion as before, + +this is what you would +see in contrast to this. + +So in other words, it's a +greatly distorted vision + +because you didn't take into +account the magnification + +factor. + +All right. + +So then what you can +do, actually, you + +can also increase the number of +electrodes in the center here. + +OK? + +And that would +mean-- in this case + +we have 428 elements-- that you +can recreate fiat lux pretty + +well with this increased +number of elements, + +where with the original set +you couldn't make anything out. + +Now, the alternate +to this would be + +that you could +take a whole bunch + +of equally-spaced electrodes, +which you can commercially buy, + +and put them in. + +But then to get the same acuity, +you would need, in this case, + +something like over +600 electrodes, + +whereas in this case you +would only need about 420. + +So because of that, +obviously we want + +to minimize the number of +things you put into the brain, + +it's desirable to use +a proportional device. + +So that's the first big step. + +Now, let's assume that you have +created a proportional device. + +The next thing would be to +see, how do you stimulate these + +through a camera? + +So what you do then +is an experiment + +in which you take +a human subject, + +and you can put a +camera on a helmet, + +and also, the person +looks at a monitor. + +And otherwise, the +rest of the world + +is excluded by having +this bezel here. + +And then the camera +looks at something, + +and then it can +display the image here. + +Well, one thing it can do, it +can display the image as it is. + +But the other thing that's +much more important, + +it can display that image +as if electrical stimulation + +had taken place. + +Now, this becomes +complicated because you + +have to do a lot of conversion +of the input from the camera + +to the computer that's going +to then drive the electrodes. + +Now, the first important +point, I mentioned this before, + +is that if you present a small +spot-- this is actual real data + +here-- you present a small spot +in the center of a small array + +of cells in the visual cortex, +you get a vigorous response, + +whether a light increment +or light decrement. + +But if you use a larger +spot, you get no response, + +meaning that the cortical cells +look at local differences. + +That has a lot to do +with what we talked about + +with the illusions. + +And so what you +have to create is + +an algorithm that mimics that. + +And so the way +you do that is you + +have these individual elements +for each of the electrodes. + +And if that individual +element in the computer that + +gets the input from the camera, +if the whole element gets + +activated, there's no real +activation of the electrode. + +But if an edge +appears like here, + +here, or here, then the +electrode is activated. + +OK? + +So you create local differences +by this conversion system, + +all right, by this +algorithm that then, + +when the camera +looks at the world, + +will respond whenever there's +an edge, an illumination + +difference. + +OK. + +So now the way this +looks is like this. + +Again, as I've told you, +whatever is in the fovea, + +the dots are smaller and +further out, but that's OK. + +So that's the basic +activation system. + +And so now what we +are going to do, + +having created +such an algorithm, + +we're going to examine +what the person who + +carries this camera on +his head can actually see. + +Now, the way this can be done, +you can either physically + +move the stimuli in the world, +or the person looks at it + +and can slowly move +his head around. + +OK? + +So let's first +look at what would + +happen if, instead of +a proportional display, + +we used an equally-spaced +display like that butterfly + +display. + +OK? + +So what I'm going to +show you here on the left + +is what the camera is viewing. + +And here I'm going to +show you what is actually + +perceived by this algorithm, by +the person, where this image is + +converted into what he's +looking at through that bezel. + +OK, you ready? + +I mean, you don't see +a square at all, right? + +What you see is, because +you're not taking into account + +the magnification factor, +you get a huge distortion. + +So now let's go move on +and ask the question, + +well, what happens when you are +using a proportional display? + +All right? + +And now we get a +rather nice story. + +Again, the visual +display's on the left, + +and the image created +is on the right. + +Ready? + +So the rule, +therefore, is that you + +must use a proportional image, +proportional display, that + +can be done either by having it +truly proportional as you put + +it into the visual cortex or by +having an equally-spaced array, + +and the computer computes +the proportional arrangement. + +But the disadvantage +of the latter + +is that you need many, +many more electrodes. + +All right. + +Now, what I'm going +to do is I'm going + +to show you whether +you can read something + +when you use a proportional +display like that. + +And in this case, we're going +to have a bunch of big letters, + +and either the letters +are going to move slowly + +across the visual +field, or your head + +is going to move slowly +with the camera like that + +to view that display +that's up on the wall. + +OK? + +So if we do that-- +are you ready? + +See if you can read it. + +OK. + +Everybody able to read that one? + +OK. + +Who remembers what +"fiat lux" means? + +I've only shown it about +four or five times. + +Let there be light. + +OK. + +So now, just to be [INAUDIBLE] +attractive about it, + +I'm going to show +you one more display. + +And this one is +a display, again, + +a series of letters +and words, is one + +that John F. Kennedy has used in +a very, very famous statement, + +which I think most +of you will remember. + +And eventually, as you +see the whole thing, + +you will be able +to put it together. + +Are you ready? + +OK. + +Everybody's seen that, right? + +People nowadays, because +of what's going on, + +are less inclined +to take his advice. + +All right. + +So that is then +the essence of what + +I was going to cover today. + +And so let me now provide +you with a brief summary. + +I will start with +the prosthetics then. + +OK? + +Research on visual +prosthetics is in its infancy, + +as I've noted. + +A great deal of +basic research is + +needed before such a device +can become effective. + +That's very unlike +what you're going + +to hear about the +auditory system. + +The brain area that holds +considerable promise + +for the prosthetic device +based on electrical stimulation + +is area V1. + +Now, a prosthetic device for +electrical stimulation of V1 + +must take into account +the magnification factor. + +That's absolutely +essential, and too many + +people are ignoring it. + +Now, in a different +color, we're going + +to talk about the illusions. + +There is no unitary +explanation for + +the great many visual +illusions extant. + +I pointed out to you +that different illusions + +have different sources and +different explanations. + +The most popular theory +explaining the Hermann grid + +illusion based on the +center/surround organization + +of retinal ganglion +cells is incorrect. + +That's a polite way of +saying it's all wrong. + +A more likely theory +is the one that + +assumes that area V1 +cells are involved. + +Retinal adaptation processes +can explain illusions + +based on aftereffects, +and you've + +seen quite a few of those. + +And many illusions disappear +under isoluminant conditions. + +And lastly, there are no viable +theories that explain illusions + +based on figure/ground +relationships. + +We know what they +are, but we don't + +know how the brain resolves +figure and ground effects. + +So that then is the end of +what I wanted to cover today. + +And next time, we are going +to talk about eye movement. + +And I hope that you +will enjoy that as well. \ No newline at end of file diff --git a/vmE4N0m67AA.txt b/vmE4N0m67AA.txt new file mode 100644 index 0000000000000000000000000000000000000000..3718c1e4964d2b08423c7f621b92a08516c413b2 --- /dev/null +++ b/vmE4N0m67AA.txt @@ -0,0 +1,9931 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT OpenCourseWare continue to + + align:start position:0% +will help MIT OpenCourseWare continue to + + + align:start position:0% +will help MIT OpenCourseWare continue to +offer high quality educational resources + + align:start position:0% +offer high quality educational resources + + + align:start position:0% +offer high quality educational resources +for free + + align:start position:0% +for free + + + align:start position:0% +for free +to make a donation or view additional + + align:start position:0% +to make a donation or view additional + + + align:start position:0% +to make a donation or view additional +materials from hundreds of MIT courses + + align:start position:0% +materials from hundreds of MIT courses + + + align:start position:0% +materials from hundreds of MIT courses +visit MIT opencourseware at ocw.mit.edu + + align:start position:0% +visit MIT opencourseware at ocw.mit.edu + + + align:start position:0% +visit MIT opencourseware at ocw.mit.edu +what I'm going to be talking about some + + align:start position:0% +what I'm going to be talking about some + + + align:start position:0% +what I'm going to be talking about some +of the fundamental work that has been + + align:start position:0% +of the fundamental work that has been + + + align:start position:0% +of the fundamental work that has been +done trying to understand neural basis + + align:start position:0% +done trying to understand neural basis + + + align:start position:0% +done trying to understand neural basis +for for memory and spatial perception + + align:start position:0% +for for memory and spatial perception + + + align:start position:0% +for for memory and spatial perception +and cognition that comes from largely + + align:start position:0% +and cognition that comes from largely + + + align:start position:0% +and cognition that comes from largely +from behavioral and electrophysiological + + align:start position:0% +from behavioral and electrophysiological + + + align:start position:0% +from behavioral and electrophysiological +studies in the brain system that's shown + + align:start position:0% +studies in the brain system that's shown + + + align:start position:0% +studies in the brain system that's shown +here at the hippocampus and as I was + + align:start position:0% +here at the hippocampus and as I was + + + align:start position:0% +here at the hippocampus and as I was +mentioning before we started this year's + + align:start position:0% +mentioning before we started this year's + + + align:start position:0% +mentioning before we started this year's +Nobel Prize was given to John Okeefe who + + align:start position:0% +Nobel Prize was given to John Okeefe who + + + align:start position:0% +Nobel Prize was given to John Okeefe who +discovered the properties of individual + + align:start position:0% +discovered the properties of individual + + + align:start position:0% +discovered the properties of individual +neurons in the hippocampus by applying + + align:start position:0% +neurons in the hippocampus by applying + + + align:start position:0% +neurons in the hippocampus by applying +these methods for recording the + + align:start position:0% +these methods for recording the + + + align:start position:0% +these methods for recording the +discharge of single cells by putting + + align:start position:0% +discharge of single cells by putting + + + align:start position:0% +discharge of single cells by putting +little wires into the brain so called + + align:start position:0% +little wires into the brain so called + + + align:start position:0% +little wires into the brain so called +extracellular recordings you put in a + + align:start position:0% +extracellular recordings you put in a + + + align:start position:0% +extracellular recordings you put in a +wire the tip of the electrode can record + + align:start position:0% +wire the tip of the electrode can record + + + align:start position:0% +wire the tip of the electrode can record +electrical discharges of cells you + + align:start position:0% +electrical discharges of cells you + + + align:start position:0% +electrical discharges of cells you +measure the discharge of cells as + + align:start position:0% +measure the discharge of cells as + + + align:start position:0% +measure the discharge of cells as +animals move around in space and you try + + align:start position:0% +animals move around in space and you try + + + align:start position:0% +animals move around in space and you try +to you know you try to figure out what + + align:start position:0% +to you know you try to figure out what + + + align:start position:0% +to you know you try to figure out what +this part of the brain does now where + + align:start position:0% +this part of the brain does now where + + + align:start position:0% +this part of the brain does now where +the observation part of science comes in + + align:start position:0% +the observation part of science comes in + + + align:start position:0% +the observation part of science comes in +in this case is interesting because it + + align:start position:0% +in this case is interesting because it + + + align:start position:0% +in this case is interesting because it +relates to another aspect of + + align:start position:0% + + + + align:start position:0% + +neuroscience and that is the + + align:start position:0% +neuroscience and that is the + + + align:start position:0% +neuroscience and that is the +relationship between the neurobiology + + align:start position:0% +relationship between the neurobiology + + + align:start position:0% +relationship between the neurobiology +and behavior and this is an approach + + align:start position:0% +and behavior and this is an approach + + + align:start position:0% +and behavior and this is an approach +known as an ERV ecological approach and + + align:start position:0% +known as an ERV ecological approach and + + + align:start position:0% +known as an ERV ecological approach and +as studying the brain systems in the + + align:start position:0% +as studying the brain systems in the + + + align:start position:0% +as studying the brain systems in the +context in which they actually they you + + align:start position:0% +context in which they actually they you + + + align:start position:0% +context in which they actually they you +know they evolved and were used and so + + align:start position:0% +know they evolved and were used and so + + + align:start position:0% +know they evolved and were used and so +that could apply to the use of song as a + + align:start position:0% +that could apply to the use of song as a + + + align:start position:0% +that could apply to the use of song as a +as a mechanism of communication and + + align:start position:0% +as a mechanism of communication and + + + align:start position:0% +as a mechanism of communication and +birds it can come from the you know + + align:start position:0% +birds it can come from the you know + + + align:start position:0% +birds it can come from the you know +finding you know finding prey in the + + align:start position:0% +finding you know finding prey in the + + + align:start position:0% +finding you know finding prey in the +dark when it comes to sound localization + + align:start position:0% +dark when it comes to sound localization + + + align:start position:0% +dark when it comes to sound localization +owls and the case of rodents + + align:start position:0% +owls and the case of rodents + + + align:start position:0% +owls and the case of rodents +o'keefe appreciated the fact that the + + align:start position:0% +o'keefe appreciated the fact that the + + + align:start position:0% +o'keefe appreciated the fact that the +campus and rodents really has a primary + + align:start position:0% +campus and rodents really has a primary + + + align:start position:0% +campus and rodents really has a primary +role in spatial navigation that animals + + align:start position:0% +role in spatial navigation that animals + + + align:start position:0% +role in spatial navigation that animals +that have damaged that the campus have + + align:start position:0% +that have damaged that the campus have + + + align:start position:0% +that have damaged that the campus have +problems with spatial navigation and the + + align:start position:0% +problems with spatial navigation and the + + + align:start position:0% +problems with spatial navigation and the +hippocampus had been studied up to that + + align:start position:0% +hippocampus had been studied up to that + + + align:start position:0% +hippocampus had been studied up to that +point using animals that were head fixed + + align:start position:0% +point using animals that were head fixed + + + align:start position:0% +point using animals that were head fixed +and so you take take a little rat you + + align:start position:0% +and so you take take a little rat you + + + align:start position:0% +and so you take take a little rat you +fix his head and the reason for fixing + + align:start position:0% +fix his head and the reason for fixing + + + align:start position:0% +fix his head and the reason for fixing +its head is for convenience largely so + + align:start position:0% +its head is for convenience largely so + + + align:start position:0% +its head is for convenience largely so +that when you place these little + + align:start position:0% +that when you place these little + + + align:start position:0% +that when you place these little +electrodes into the brain animal doesn't + + align:start position:0% +electrodes into the brain animal doesn't + + + align:start position:0% +electrodes into the brain animal doesn't +move it all moves like probe moves you + + align:start position:0% +move it all moves like probe moves you + + + align:start position:0% +move it all moves like probe moves you +can't get good recordings so you need to + + align:start position:0% +can't get good recordings so you need to + + + align:start position:0% +can't get good recordings so you need to +have you need to keep the preparation + + align:start position:0% +have you need to keep the preparation + + + align:start position:0% +have you need to keep the preparation +fixed so you fix the animals head then + + align:start position:0% +fixed so you fix the animals head then + + + align:start position:0% +fixed so you fix the animals head then +you figure out ways to actually look how + + align:start position:0% +you figure out ways to actually look how + + + align:start position:0% +you figure out ways to actually look how +to study the system given the + + align:start position:0% +to study the system given the + + + align:start position:0% +to study the system given the +constraints of the methodology and that + + align:start position:0% +constraints of the methodology and that + + + align:start position:0% +constraints of the methodology and that +involved largely before John Okeefe and + + align:start position:0% +involved largely before John Okeefe and + + + align:start position:0% +involved largely before John Okeefe and +1970 using the methods of classical + + align:start position:0% +1970 using the methods of classical + + + align:start position:0% +1970 using the methods of classical +conditioning so familiar with basic + + align:start position:0% +conditioning so familiar with basic + + + align:start position:0% +conditioning so familiar with basic +learning theory and you know how do we + + align:start position:0% +learning theory and you know how do we + + + align:start position:0% +learning theory and you know how do we +learn how to do things + + align:start position:0% +learn how to do things + + + align:start position:0% +learn how to do things +most basically chaining together + + align:start position:0% +most basically chaining together + + + align:start position:0% +most basically chaining together +stimulus-response associations you see + + align:start position:0% +stimulus-response associations you see + + + align:start position:0% +stimulus-response associations you see +something you do something you've got + + align:start position:0% +something you do something you've got + + + align:start position:0% +something you do something you've got +rewarded for doing that you're more + + align:start position:0% +rewarded for doing that you're more + + + align:start position:0% +rewarded for doing that you're more +likely to do that again in the future + + align:start position:0% +likely to do that again in the future + + + align:start position:0% +likely to do that again in the future +this is this is basic Pavlovian + + align:start position:0% +this is this is basic Pavlovian + + + align:start position:0% +this is this is basic Pavlovian +conditioning I ring a bell you get food + + align:start position:0% +conditioning I ring a bell you get food + + + align:start position:0% +conditioning I ring a bell you get food +okay you associate that with the food + + align:start position:0% +okay you associate that with the food + + + align:start position:0% +okay you associate that with the food +and so that was the thinking that all of + + align:start position:0% +and so that was the thinking that all of + + + align:start position:0% +and so that was the thinking that all of +cognition can be built up from basic + + align:start position:0% +cognition can be built up from basic + + + align:start position:0% +cognition can be built up from basic +stimulus-response associations but there + + align:start position:0% +stimulus-response associations but there + + + align:start position:0% +stimulus-response associations but there +was this movement around the time that + + align:start position:0% +was this movement around the time that + + + align:start position:0% +was this movement around the time that +O'Keefe was doing this work that that + + align:start position:0% +O'Keefe was doing this work that that + + + align:start position:0% +O'Keefe was doing this work that that +proposed that that was insufficient that + + align:start position:0% +proposed that that was insufficient that + + + align:start position:0% +proposed that that was insufficient that +simple behavioral simple stimulus + + align:start position:0% +simple behavioral simple stimulus + + + align:start position:0% +simple behavioral simple stimulus +responsibility was insufficient that + + align:start position:0% +responsibility was insufficient that + + + align:start position:0% +responsibility was insufficient that +there was some kind of internal + + align:start position:0% +there was some kind of internal + + + align:start position:0% +there was some kind of internal +foundation upon which learning was was + + align:start position:0% +foundation upon which learning was was + + + align:start position:0% +foundation upon which learning was was +applied and this was the so called + + align:start position:0% +applied and this was the so called + + + align:start position:0% +applied and this was the so called +cognitive theory of of learning and + + align:start position:0% +cognitive theory of of learning and + + + align:start position:0% +cognitive theory of of learning and +memory and the hippocampus was posited + + align:start position:0% +memory and the hippocampus was posited + + + align:start position:0% +memory and the hippocampus was posited +to be the site of one property of this + + align:start position:0% +to be the site of one property of this + + + align:start position:0% +to be the site of one property of this +cognitive learning as applied to space + + align:start position:0% +cognitive learning as applied to space + + + align:start position:0% +cognitive learning as applied to space +and the observation was actually a + + align:start position:0% +and the observation was actually a + + + align:start position:0% +and the observation was actually a +fairly simple one if you take a rat ic1 + + align:start position:0% +fairly simple one if you take a rat ic1 + + + align:start position:0% +fairly simple one if you take a rat ic1 +to learn learn something that is it you + + align:start position:0% +to learn learn something that is it you + + + align:start position:0% +to learn learn something that is it you +want to learn to I know you know + + align:start position:0% +want to learn to I know you know + + + align:start position:0% +want to learn to I know you know +associate a associate a you know a cue + + align:start position:0% +associate a associate a you know a cue + + + align:start position:0% +associate a associate a you know a cue +with food or + + align:start position:0% +with food or + + + align:start position:0% +with food or +you know you want to train it to go over + + align:start position:0% +you know you want to train it to go over + + + align:start position:0% +you know you want to train it to go over +and you know press a lever for food you + + align:start position:0% +and you know press a lever for food you + + + align:start position:0% +and you know press a lever for food you +want to learn something and you do this + + align:start position:0% +want to learn something and you do this + + + align:start position:0% +want to learn something and you do this +in an environment that put it in a box + + align:start position:0% +in an environment that put it in a box + + + align:start position:0% +in an environment that put it in a box +well if you take her out you put it in + + align:start position:0% +well if you take her out you put it in + + + align:start position:0% +well if you take her out you put it in +that box let's say the date before and + + align:start position:0% +that box let's say the date before and + + + align:start position:0% +that box let's say the date before and +just let it wander around does nothing + + align:start position:0% +just let it wander around does nothing + + + align:start position:0% +just let it wander around does nothing +it's just explores the space you take it + + align:start position:0% +it's just explores the space you take it + + + align:start position:0% +it's just explores the space you take it +out and now we take two rats one that's + + align:start position:0% +out and now we take two rats one that's + + + align:start position:0% +out and now we take two rats one that's +been in the box before and one that has + + align:start position:0% +been in the box before and one that has + + + align:start position:0% +been in the box before and one that has +not been in the box before and the one + + align:start position:0% +not been in the box before and the one + + + align:start position:0% +not been in the box before and the one +the wrath has been in the box before + + align:start position:0% +the wrath has been in the box before + + + align:start position:0% +the wrath has been in the box before +we'll learn faster then the animal has + + align:start position:0% +we'll learn faster then the animal has + + + align:start position:0% +we'll learn faster then the animal has +not been in the box you say why would + + align:start position:0% +not been in the box you say why would + + + align:start position:0% +not been in the box you say why would +why would just passive exposure to that + + align:start position:0% +why would just passive exposure to that + + + align:start position:0% +why would just passive exposure to that +box enhance its learning and this + + align:start position:0% +box enhance its learning and this + + + align:start position:0% +box enhance its learning and this +phenomenon I was latent learning the + + align:start position:0% +phenomenon I was latent learning the + + + align:start position:0% +phenomenon I was latent learning the +animal had learned something that he + + align:start position:0% +animal had learned something that he + + + align:start position:0% +animal had learned something that he +could then apply to this new learning + + align:start position:0% +could then apply to this new learning + + + align:start position:0% +could then apply to this new learning +even though it was not instructive you + + align:start position:0% +even though it was not instructive you + + + align:start position:0% +even though it was not instructive you +didn't nothing that wasn't rewarded for + + align:start position:0% +didn't nothing that wasn't rewarded for + + + align:start position:0% +didn't nothing that wasn't rewarded for +doing anything it just explored and so + + align:start position:0% +doing anything it just explored and so + + + align:start position:0% +doing anything it just explored and so +this idea that there was some sort of + + align:start position:0% +this idea that there was some sort of + + + align:start position:0% +this idea that there was some sort of +latent capacity to enhance learning was + + align:start position:0% +latent capacity to enhance learning was + + + align:start position:0% +latent capacity to enhance learning was +motivated the study of the hippocampus + + align:start position:0% +motivated the study of the hippocampus + + + align:start position:0% +motivated the study of the hippocampus +in the context of non head fixed + + align:start position:0% +in the context of non head fixed + + + align:start position:0% +in the context of non head fixed +recording and so O'Keefe's real insight + + align:start position:0% +recording and so O'Keefe's real insight + + + align:start position:0% +recording and so O'Keefe's real insight +in fact the paper that was cited for you + + align:start position:0% +in fact the paper that was cited for you + + + align:start position:0% +in fact the paper that was cited for you +know for the Nobel Prize was the paper + + align:start position:0% +know for the Nobel Prize was the paper + + + align:start position:0% +know for the Nobel Prize was the paper +in which he first recorded from these + + align:start position:0% +in which he first recorded from these + + + align:start position:0% +in which he first recorded from these +cells and all he did was just take the + + align:start position:0% +cells and all he did was just take the + + + align:start position:0% +cells and all he did was just take the +animals out of the ear bars so he took + + align:start position:0% +animals out of the ear bars so he took + + + align:start position:0% +animals out of the ear bars so he took +the animal out of yours and just let it + + align:start position:0% +the animal out of yours and just let it + + + align:start position:0% +the animal out of yours and just let it +run around on a tabletop just like this + + align:start position:0% +run around on a tabletop just like this + + + align:start position:0% +run around on a tabletop just like this +actually as a table at the University + + align:start position:0% +actually as a table at the University + + + align:start position:0% +actually as a table at the University +College London about the size where this + + align:start position:0% +College London about the size where this + + + align:start position:0% +College London about the size where this +rat just kind of wandered around and he + + align:start position:0% +rat just kind of wandered around and he + + + align:start position:0% +rat just kind of wandered around and he +made observations oh here's a cell that + + align:start position:0% +made observations oh here's a cell that + + + align:start position:0% +made observations oh here's a cell that +fires when the animal goes over to the + + align:start position:0% +fires when the animal goes over to the + + + align:start position:0% +fires when the animal goes over to the +left-hand side and very descriptive but + + align:start position:0% +left-hand side and very descriptive but + + + align:start position:0% +left-hand side and very descriptive but +the key insight was to study the + + align:start position:0% +the key insight was to study the + + + align:start position:0% +the key insight was to study the +hippocampus when rats are doing what + + align:start position:0% +hippocampus when rats are doing what + + + align:start position:0% +hippocampus when rats are doing what +rats normally do explore in space so it + + align:start position:0% +rats normally do explore in space so it + + + align:start position:0% +rats normally do explore in space so it +was this ethological approach and what + + align:start position:0% +was this ethological approach and what + + + align:start position:0% +was this ethological approach and what +he discovered was that and that these + + align:start position:0% +he discovered was that and that these + + + align:start position:0% +he discovered was that and that these +cells cells in the hippocampus and this + + align:start position:0% +cells cells in the hippocampus and this + + + align:start position:0% +cells cells in the hippocampus and this +is a cross-section the campus is found + + align:start position:0% +is a cross-section the campus is found + + + align:start position:0% +is a cross-section the campus is found +here it's in the medial temporal lobes + + align:start position:0% +here it's in the medial temporal lobes + + + align:start position:0% +here it's in the medial temporal lobes +it's the name hippocampus comes from the + + align:start position:0% +it's the name hippocampus comes from the + + + align:start position:0% +it's the name hippocampus comes from the +Greek for C horror so in humans it sort + + align:start position:0% +Greek for C horror so in humans it sort + + + align:start position:0% +Greek for C horror so in humans it sort +of looks like a seahorse the regions + + align:start position:0% +of looks like a seahorse the regions + + + align:start position:0% +of looks like a seahorse the regions +here the terminology ca these they're + + align:start position:0% +here the terminology ca these they're + + + align:start position:0% +here the terminology ca these they're +these different fields of hippocampus + + align:start position:0% +these different fields of hippocampus + + + align:start position:0% +these different fields of hippocampus +comes from Cornell Montes or Amin's horn + + align:start position:0% +comes from Cornell Montes or Amin's horn + + + align:start position:0% +comes from Cornell Montes or Amin's horn +that's because it looks like a ram's + + align:start position:0% +that's because it looks like a ram's + + + align:start position:0% +that's because it looks like a ram's +horn so if you think about this like + + align:start position:0% +horn so if you think about this like + + + align:start position:0% +horn so if you think about this like +little little ram's horns right here put + + align:start position:0% +little little ram's horns right here put + + + align:start position:0% +little little ram's horns right here put +them anytime + + align:start position:0% +them anytime + + + align:start position:0% +them anytime +the lobes and you move them in there + + align:start position:0% +the lobes and you move them in there + + + align:start position:0% +the lobes and you move them in there +that's where your hippocampus is just + + align:start position:0% +that's where your hippocampus is just + + + align:start position:0% +that's where your hippocampus is just +like this and if you make a + + align:start position:0% +like this and if you make a + + + align:start position:0% +like this and if you make a +cross-section slice through that this is + + align:start position:0% +cross-section slice through that this is + + + align:start position:0% +cross-section slice through that this is +the circuit so information comes in from + + align:start position:0% +the circuit so information comes in from + + + align:start position:0% +the circuit so information comes in from +across the brain converges in the + + align:start position:0% +across the brain converges in the + + + align:start position:0% +across the brain converges in the +primary input to the hippocampus that's + + align:start position:0% +primary input to the hippocampus that's + + + align:start position:0% +primary input to the hippocampus that's +called the internal cortex which is what + + align:start position:0% +called the internal cortex which is what + + + align:start position:0% +called the internal cortex which is what +the other the the other Nobel Prize was + + align:start position:0% +the other the the other Nobel Prize was + + + align:start position:0% +the other the the other Nobel Prize was +awarded to the husband-and-wife team + + align:start position:0% +awarded to the husband-and-wife team + + + align:start position:0% +awarded to the husband-and-wife team +that had identified discovered and + + align:start position:0% +that had identified discovered and + + + align:start position:0% +that had identified discovered and +identified the properties of cells in + + align:start position:0% +identified the properties of cells in + + + align:start position:0% +identified the properties of cells in +the internal cortex these so called grid + + align:start position:0% +the internal cortex these so called grid + + + align:start position:0% +the internal cortex these so called grid +cells that seem to carry information + + align:start position:0% +cells that seem to carry information + + + align:start position:0% +cells that seem to carry information +about actual seemed like Cartesian like + + align:start position:0% +about actual seemed like Cartesian like + + + align:start position:0% +about actual seemed like Cartesian like +spatial information conveyed in the P + + align:start position:0% +spatial information conveyed in the P + + + align:start position:0% +spatial information conveyed in the P +campus so stuff comes in from the rest + + align:start position:0% +campus so stuff comes in from the rest + + + align:start position:0% +campus so stuff comes in from the rest +of the brain converges an internal + + align:start position:0% +of the brain converges an internal + + + align:start position:0% +of the brain converges an internal +cortex and then goes around this little + + align:start position:0% +cortex and then goes around this little + + + align:start position:0% +cortex and then goes around this little +loop from these these three primary + + align:start position:0% +loop from these these three primary + + + align:start position:0% +loop from these these three primary +subfields the dentate gyrus c8 cornrow - + + align:start position:0% +subfields the dentate gyrus c8 cornrow - + + + align:start position:0% +subfields the dentate gyrus c8 cornrow - +3 C a1 cibecue l'm back on again so it + + align:start position:0% +3 C a1 cibecue l'm back on again so it + + + align:start position:0% +3 C a1 cibecue l'm back on again so it +goes through this loop classically it + + align:start position:0% +goes through this loop classically it + + + align:start position:0% +goes through this loop classically it +had been referred to as the Tri synaptic + + align:start position:0% +had been referred to as the Tri synaptic + + + align:start position:0% +had been referred to as the Tri synaptic +loop one synapse dente CA 3 C a1 and + + align:start position:0% +loop one synapse dente CA 3 C a1 and + + + align:start position:0% +loop one synapse dente CA 3 C a1 and +then back out and again recordings in + + align:start position:0% +then back out and again recordings in + + + align:start position:0% +then back out and again recordings in +this part of the hippocampus revealed + + align:start position:0% +this part of the hippocampus revealed + + + align:start position:0% +this part of the hippocampus revealed +the properties at all which I'll mention + + align:start position:0% +the properties at all which I'll mention + + + align:start position:0% +the properties at all which I'll mention +and that is these cells respond to + + align:start position:0% +and that is these cells respond to + + + align:start position:0% +and that is these cells respond to +locations in space but prior to that the + + align:start position:0% +locations in space but prior to that the + + + align:start position:0% +locations in space but prior to that the +selector physiological work in rodents + + align:start position:0% +selector physiological work in rodents + + + align:start position:0% +selector physiological work in rodents +there had been human neuropsychological + + align:start position:0% +there had been human neuropsychological + + + align:start position:0% +there had been human neuropsychological +work in particular the seminal case of + + align:start position:0% +work in particular the seminal case of + + + align:start position:0% +work in particular the seminal case of +the patient HM who had been studied here + + align:start position:0% +the patient HM who had been studied here + + + align:start position:0% +the patient HM who had been studied here +from for many decades before he just + + align:start position:0% +from for many decades before he just + + + align:start position:0% +from for many decades before he just +recently passed away known as HM hen + + align:start position:0% +recently passed away known as HM hen + + + align:start position:0% +recently passed away known as HM hen +neural iesson as he is as he's sort of + + align:start position:0% +neural iesson as he is as he's sort of + + + align:start position:0% +neural iesson as he is as he's sort of +now revealed sort of recently revealed + + align:start position:0% +now revealed sort of recently revealed + + + align:start position:0% +now revealed sort of recently revealed +to be a patient who had undergone + + align:start position:0% +to be a patient who had undergone + + + align:start position:0% +to be a patient who had undergone +bilateral resection and medial temporal + + align:start position:0% +bilateral resection and medial temporal + + + align:start position:0% +bilateral resection and medial temporal +lobes cut out parts of his of the + + align:start position:0% +lobes cut out parts of his of the + + + align:start position:0% +lobes cut out parts of his of the +hippocampus and other associated medial + + align:start position:0% +hippocampus and other associated medial + + + align:start position:0% +hippocampus and other associated medial +temporal lobe structures to treat + + align:start position:0% +temporal lobe structures to treat + + + align:start position:0% +temporal lobe structures to treat +intractable epilepsy he subsequently + + align:start position:0% +intractable epilepsy he subsequently + + + align:start position:0% +intractable epilepsy he subsequently +Billy to form any new memories + + align:start position:0% +Billy to form any new memories + + + align:start position:0% +Billy to form any new memories +so had permanent + + align:start position:0% +so had permanent + + + align:start position:0% +so had permanent +permanent answer and tear great couldn't + + align:start position:0% +permanent answer and tear great couldn't + + + align:start position:0% +permanent answer and tear great couldn't +form any new memories going on going + + align:start position:0% +form any new memories going on going + + + align:start position:0% +form any new memories going on going +forward in the future and lost some of + + align:start position:0% +forward in the future and lost some of + + + align:start position:0% +forward in the future and lost some of +his older memories so you lose memories + + align:start position:0% +his older memories so you lose memories + + + align:start position:0% +his older memories so you lose memories +in humans rodents can't navigate in + + align:start position:0% +in humans rodents can't navigate in + + + align:start position:0% +in humans rodents can't navigate in +space also humans have a spatial deficit + + align:start position:0% +space also humans have a spatial deficit + + + align:start position:0% +space also humans have a spatial deficit +so there's some connection between space + + align:start position:0% +so there's some connection between space + + + align:start position:0% +so there's some connection between space +and memory and the question is what is + + align:start position:0% +and memory and the question is what is + + + align:start position:0% +and memory and the question is what is +that what would were linked spatial + + align:start position:0% +that what would were linked spatial + + + align:start position:0% +that what would were linked spatial +navigation and memory but not just kind + + align:start position:0% +navigation and memory but not just kind + + + align:start position:0% +navigation and memory but not just kind +of any kind of memory what we referred + + align:start position:0% +of any kind of memory what we referred + + + align:start position:0% +of any kind of memory what we referred +to as episodic memory or memory for + + align:start position:0% +to as episodic memory or memory for + + + align:start position:0% +to as episodic memory or memory for +events or experiences and so the working + + align:start position:0% +events or experiences and so the working + + + align:start position:0% +events or experiences and so the working +and hypothesis is that these two things + + align:start position:0% +and hypothesis is that these two things + + + align:start position:0% +and hypothesis is that these two things +are really connected by a need a + + align:start position:0% +are really connected by a need a + + + align:start position:0% +are really connected by a need a +computational imperative to maintain + + align:start position:0% +computational imperative to maintain + + + align:start position:0% +computational imperative to maintain +information about time order and that is + + align:start position:0% +information about time order and that is + + + align:start position:0% +information about time order and that is +if you're going to use experience to + + align:start position:0% +if you're going to use experience to + + + align:start position:0% +if you're going to use experience to +guide future behavior you need to figure + + align:start position:0% +guide future behavior you need to figure + + + align:start position:0% +guide future behavior you need to figure +out what the causal relationships are + + align:start position:0% +out what the causal relationships are + + + align:start position:0% +out what the causal relationships are +between events in the world you know why + + align:start position:0% +between events in the world you know why + + + align:start position:0% +between events in the world you know why +did you know I if I if I see a and B + + align:start position:0% +did you know I if I if I see a and B + + + align:start position:0% +did you know I if I if I see a and B +what I really want to figure out I don't + + align:start position:0% +what I really want to figure out I don't + + + align:start position:0% +what I really want to figure out I don't +just want to record the fact that a and + + align:start position:0% +just want to record the fact that a and + + + align:start position:0% +just want to record the fact that a and +B happen together ultimately I want to + + align:start position:0% +B happen together ultimately I want to + + + align:start position:0% +B happen together ultimately I want to +try to understand the relationship + + align:start position:0% +try to understand the relationship + + + align:start position:0% +try to understand the relationship +between a and B did a cos B or what you + + align:start position:0% +between a and B did a cos B or what you + + + align:start position:0% +between a and B did a cos B or what you +know how might I actually predict B + + align:start position:0% +know how might I actually predict B + + + align:start position:0% +know how might I actually predict B +given a and the way I would do that + + align:start position:0% +given a and the way I would do that + + + align:start position:0% +given a and the way I would do that +would be to construct some kind of + + align:start position:0% +would be to construct some kind of + + + align:start position:0% +would be to construct some kind of +simple internal model a predictive model + + align:start position:0% +simple internal model a predictive model + + + align:start position:0% +simple internal model a predictive model +that's based on experience and so the + + align:start position:0% +that's based on experience and so the + + + align:start position:0% +that's based on experience and so the +idea is hippocampus captures experience + + align:start position:0% +idea is hippocampus captures experience + + + align:start position:0% +idea is hippocampus captures experience +and then some through some process which + + align:start position:0% +and then some through some process which + + + align:start position:0% +and then some through some process which +we will refer to as the process of + + align:start position:0% +we will refer to as the process of + + + align:start position:0% +we will refer to as the process of +consolidation translates experience into + + align:start position:0% +consolidation translates experience into + + + align:start position:0% +consolidation translates experience into +some working model that can predict + + align:start position:0% +some working model that can predict + + + align:start position:0% +some working model that can predict +events and can be used to guide behavior + + align:start position:0% +events and can be used to guide behavior + + + align:start position:0% +events and can be used to guide behavior +and decision-making and critical to that + + align:start position:0% +and decision-making and critical to that + + + align:start position:0% +and decision-making and critical to that +is just the idea of time and in + + align:start position:0% +is just the idea of time and in + + + align:start position:0% +is just the idea of time and in +particular time order so as I mentioned + + align:start position:0% +particular time order so as I mentioned + + + align:start position:0% +particular time order so as I mentioned +the the use of very simple technology in + + align:start position:0% +the the use of very simple technology in + + + align:start position:0% +the the use of very simple technology in +this case extracellular near + + align:start position:0% +this case extracellular near + + + align:start position:0% +this case extracellular near +physiological recording taking a tiny + + align:start position:0% +physiological recording taking a tiny + + + align:start position:0% +physiological recording taking a tiny +wire this wire is actually four small + + align:start position:0% +wire this wire is actually four small + + + align:start position:0% +wire this wire is actually four small +wires each one about 10 microns across + + align:start position:0% +wires each one about 10 microns across + + + align:start position:0% +wires each one about 10 microns across +you twist them together in a little + + align:start position:0% +you twist them together in a little + + + align:start position:0% +you twist them together in a little +bundle the bundle is about 35 microns + + align:start position:0% +bundle the bundle is about 35 microns + + + align:start position:0% +bundle the bundle is about 35 microns +human hair is on the order of about 50 + + align:start position:0% +human hair is on the order of about 50 + + + align:start position:0% +human hair is on the order of about 50 +typically about 50 microns so these are + + align:start position:0% +typically about 50 microns so these are + + + align:start position:0% +typically about 50 microns so these are +little these are wires or electrodes + + align:start position:0% +little these are wires or electrodes + + + align:start position:0% +little these are wires or electrodes +multi contact electrodes about as large + + align:start position:0% +multi contact electrodes about as large + + + align:start position:0% +multi contact electrodes about as large +as a hair human hair we thread these + + align:start position:0% +as a hair human hair we thread these + + + align:start position:0% +as a hair human hair we thread these +things through the little oil rig + + align:start position:0% +things through the little oil rig + + + align:start position:0% +things through the little oil rig +drilling device here which is which I'll + + align:start position:0% +drilling device here which is which I'll + + + align:start position:0% +drilling device here which is which I'll +these little micro manipulators + + align:start position:0% +these little micro manipulators + + + align:start position:0% +these little micro manipulators +allow this wire to be driven down + + align:start position:0% +allow this wire to be driven down + + + align:start position:0% +allow this wire to be driven down +through Sperry small guide cannula and + + align:start position:0% +through Sperry small guide cannula and + + + align:start position:0% +through Sperry small guide cannula and +sew out the bottom will will be a number + + align:start position:0% +sew out the bottom will will be a number + + + align:start position:0% +sew out the bottom will will be a number +of these independent individual + + align:start position:0% +of these independent individual + + + align:start position:0% +of these independent individual +electrodes each controlled by these by + + align:start position:0% +electrodes each controlled by these by + + + align:start position:0% +electrodes each controlled by these by +their own micro manipulator so we can + + align:start position:0% +their own micro manipulator so we can + + + align:start position:0% +their own micro manipulator so we can +send these electrodes down this entire + + align:start position:0% +send these electrodes down this entire + + + align:start position:0% +send these electrodes down this entire +device in this case weighs anywhere from + + align:start position:0% +device in this case weighs anywhere from + + + align:start position:0% +device in this case weighs anywhere from +like 12 to 12 to 20 grams and this can + + align:start position:0% +like 12 to 12 to 20 grams and this can + + + align:start position:0% +like 12 to 12 to 20 grams and this can +be placed on an animal's head + + align:start position:0% +be placed on an animal's head + + + align:start position:0% +be placed on an animal's head +permanently or chronically and that is + + align:start position:0% +permanently or chronically and that is + + + align:start position:0% +permanently or chronically and that is +that it once it goes on doesn't come off + + align:start position:0% +that it once it goes on doesn't come off + + + align:start position:0% +that it once it goes on doesn't come off +so they all have this this little helmet + + align:start position:0% +so they all have this this little helmet + + + align:start position:0% +so they all have this this little helmet +like thing on their head small opening + + align:start position:0% +like thing on their head small opening + + + align:start position:0% +like thing on their head small opening +is made in the in the skull the wires + + align:start position:0% +is made in the in the skull the wires + + + align:start position:0% +is made in the in the skull the wires +are sent through and the whole surgical + + align:start position:0% +are sent through and the whole surgical + + + align:start position:0% +are sent through and the whole surgical +procedure takes maybe 30 to 45 minutes + + align:start position:0% +procedure takes maybe 30 to 45 minutes + + + align:start position:0% +procedure takes maybe 30 to 45 minutes +it's like an outpatient thing probably + + align:start position:0% +it's like an outpatient thing probably + + + align:start position:0% +it's like an outpatient thing probably +take longer to have your wisdom teeth + + align:start position:0% +take longer to have your wisdom teeth + + + align:start position:0% +take longer to have your wisdom teeth +pulled and to have a brain implant + + align:start position:0% +pulled and to have a brain implant + + + align:start position:0% +pulled and to have a brain implant +installed then once this is installed + + align:start position:0% +installed then once this is installed + + + align:start position:0% +installed then once this is installed +these electrodes can be driven down and + + align:start position:0% +these electrodes can be driven down and + + + align:start position:0% +these electrodes can be driven down and +placed permanently it gives you the + + align:start position:0% +placed permanently it gives you the + + + align:start position:0% +placed permanently it gives you the +ability to monitor pattern activity + + align:start position:0% +ability to monitor pattern activity + + + align:start position:0% +ability to monitor pattern activity +across large populations over you know + + align:start position:0% +across large populations over you know + + + align:start position:0% +across large populations over you know +long periods of time days weeks months + + align:start position:0% +long periods of time days weeks months + + + align:start position:0% +long periods of time days weeks months +so you have a kind of tapped into + + align:start position:0% +so you have a kind of tapped into + + + align:start position:0% +so you have a kind of tapped into +activity in this brain area and you can + + align:start position:0% +activity in this brain area and you can + + + align:start position:0% +activity in this brain area and you can +monitor as animals experience learn and + + align:start position:0% +monitor as animals experience learn and + + + align:start position:0% +monitor as animals experience learn and +recall and this is what the raw data + + align:start position:0% +recall and this is what the raw data + + + align:start position:0% +recall and this is what the raw data +looks like this is a cartoon of the + + align:start position:0% +looks like this is a cartoon of the + + + align:start position:0% +looks like this is a cartoon of the +electrode or contacts the idea with the + + align:start position:0% +electrode or contacts the idea with the + + + align:start position:0% +electrode or contacts the idea with the +four contacts is it gives you the + + align:start position:0% +four contacts is it gives you the + + + align:start position:0% +four contacts is it gives you the +ability to triangulate location much as + + align:start position:0% +ability to triangulate location much as + + + align:start position:0% +ability to triangulate location much as +you kind of scare stereoscopically can + + align:start position:0% +you kind of scare stereoscopically can + + + align:start position:0% +you kind of scare stereoscopically can +determine depth these four contacts will + + align:start position:0% +determine depth these four contacts will + + + align:start position:0% +determine depth these four contacts will +give you the ability to triangulate + + align:start position:0% +give you the ability to triangulate + + + align:start position:0% +give you the ability to triangulate +things in three-dimensional space one of + + align:start position:0% +things in three-dimensional space one of + + + align:start position:0% +things in three-dimensional space one of +the properties of this hippocampal + + align:start position:0% +the properties of this hippocampal + + + align:start position:0% +the properties of this hippocampal +circuit and that is so this little + + align:start position:0% +circuit and that is so this little + + + align:start position:0% +circuit and that is so this little +cross-section you think of imagine a + + align:start position:0% +cross-section you think of imagine a + + + align:start position:0% +cross-section you think of imagine a +neuron here and so they're going to be + + align:start position:0% +neuron here and so they're going to be + + + align:start position:0% +neuron here and so they're going to be +you know again neurons distributed + + align:start position:0% +you know again neurons distributed + + + align:start position:0% +you know again neurons distributed +across this you know across the + + align:start position:0% +across this you know across the + + + align:start position:0% +across this you know across the +hippocampus in the rat there are on the + + align:start position:0% +hippocampus in the rat there are on the + + + align:start position:0% +hippocampus in the rat there are on the +order of maybe 200,000 cells in areas C + + align:start position:0% +order of maybe 200,000 cells in areas C + + + align:start position:0% +order of maybe 200,000 cells in areas C +a1 and the entire hippocampus there are + + align:start position:0% +a1 and the entire hippocampus there are + + + align:start position:0% +a1 and the entire hippocampus there are +on the order of me 1 to 2 million cells + + align:start position:0% +on the order of me 1 to 2 million cells + + + align:start position:0% +on the order of me 1 to 2 million cells +and if you drop an electrode anyplace + + align:start position:0% +and if you drop an electrode anyplace + + + align:start position:0% +and if you drop an electrode anyplace +into the campus you will find cells that + + align:start position:0% +into the campus you will find cells that + + + align:start position:0% +into the campus you will find cells that +have this kind of spatial property + + align:start position:0% +have this kind of spatial property + + + align:start position:0% +have this kind of spatial property +and so what that says is that spatial + + align:start position:0% +and so what that says is that spatial + + + align:start position:0% +and so what that says is that spatial +information is distributed not you know + + align:start position:0% +information is distributed not you know + + + align:start position:0% +information is distributed not you know +in a topographic way in other words is + + align:start position:0% +in a topographic way in other words is + + + align:start position:0% +in a topographic way in other words is +not you know one location in space is + + align:start position:0% +not you know one location in space is + + + align:start position:0% +not you know one location in space is +mapped into one location on the brain in + + align:start position:0% +mapped into one location on the brain in + + + align:start position:0% +mapped into one location on the brain in +the in the hippocampus unlike some of + + align:start position:0% +the in the hippocampus unlike some of + + + align:start position:0% +the in the hippocampus unlike some of +the sensory areas that you might that + + align:start position:0% +the sensory areas that you might that + + + align:start position:0% +the sensory areas that you might that +have this kind of topography runs for + + align:start position:0% +have this kind of topography runs for + + + align:start position:0% +have this kind of topography runs for +instance if you record in the in the + + align:start position:0% +instance if you record in the in the + + + align:start position:0% +instance if you record in the in the +visual cortex where there's there would + + align:start position:0% +visual cortex where there's there would + + + align:start position:0% +visual cortex where there's there would +be some correspondence between location + + align:start position:0% +be some correspondence between location + + + align:start position:0% +be some correspondence between location +and visual field and the location of + + align:start position:0% +and visual field and the location of + + + align:start position:0% +and visual field and the location of +cells in the cortex that respond to that + + align:start position:0% +cells in the cortex that respond to that + + + align:start position:0% +cells in the cortex that respond to that +is so called retina topic mapping visual + + align:start position:0% +is so called retina topic mapping visual + + + align:start position:0% +is so called retina topic mapping visual +field mapped onto the anatomy same thing + + align:start position:0% +field mapped onto the anatomy same thing + + + align:start position:0% +field mapped onto the anatomy same thing +with like the somatosensory system as I + + align:start position:0% +with like the somatosensory system as I + + + align:start position:0% +with like the somatosensory system as I +move and you know I touch different + + align:start position:0% +move and you know I touch different + + + align:start position:0% +move and you know I touch different +parts of the body the cells that respond + + align:start position:0% +parts of the body the cells that respond + + + align:start position:0% +parts of the body the cells that respond +to that will be mapped out in a you know + + align:start position:0% +to that will be mapped out in a you know + + + align:start position:0% +to that will be mapped out in a you know +in a sort of largely one-to-one + + align:start position:0% +in a sort of largely one-to-one + + + align:start position:0% +in a sort of largely one-to-one +correspondence between the adjacency of + + align:start position:0% +correspondence between the adjacency of + + + align:start position:0% +correspondence between the adjacency of +stimuli in the input space and jccc of + + align:start position:0% +stimuli in the input space and jccc of + + + align:start position:0% +stimuli in the input space and jccc of +the representation in the neural space + + align:start position:0% +the representation in the neural space + + + align:start position:0% +the representation in the neural space +that does not occur in the campus two + + align:start position:0% +that does not occur in the campus two + + + align:start position:0% +that does not occur in the campus two +cells that are right next to one another + + align:start position:0% +cells that are right next to one another + + + align:start position:0% +cells that are right next to one another +are no more likely to respond to nearby + + align:start position:0% +are no more likely to respond to nearby + + + align:start position:0% +are no more likely to respond to nearby +locations in space than two cells that + + align:start position:0% +locations in space than two cells that + + + align:start position:0% +locations in space than two cells that +are distant from one another so as we'll + + align:start position:0% +are distant from one another so as we'll + + + align:start position:0% +are distant from one another so as we'll +discuss the principle of information + + align:start position:0% +discuss the principle of information + + + align:start position:0% +discuss the principle of information +representation hippocampus appears to be + + align:start position:0% +representation hippocampus appears to be + + + align:start position:0% +representation hippocampus appears to be +one of kind of sparse distributed + + align:start position:0% +one of kind of sparse distributed + + + align:start position:0% +one of kind of sparse distributed +patterning that you have lots of cells + + align:start position:0% +patterning that you have lots of cells + + + align:start position:0% +patterning that you have lots of cells +that will that will kind of respond to + + align:start position:0% +that will that will kind of respond to + + + align:start position:0% +that will that will kind of respond to +different environments and individual + + align:start position:0% +different environments and individual + + + align:start position:0% +different environments and individual +cells don't have a unique relationship + + align:start position:0% +cells don't have a unique relationship + + + align:start position:0% +cells don't have a unique relationship +to locations it's really the pattern + + align:start position:0% +to locations it's really the pattern + + + align:start position:0% +to locations it's really the pattern +across cells that gives you a unique + + align:start position:0% +across cells that gives you a unique + + + align:start position:0% +across cells that gives you a unique +signature or code we're taking advantage + + align:start position:0% +signature or code we're taking advantage + + + align:start position:0% +signature or code we're taking advantage +of the fact that you don't necessarily + + align:start position:0% +of the fact that you don't necessarily + + + align:start position:0% +of the fact that you don't necessarily +have to place the electrodes at at the + + align:start position:0% +have to place the electrodes at at the + + + align:start position:0% +have to place the electrodes at at the +proper place in order to see these get + + align:start position:0% +proper place in order to see these get + + + align:start position:0% +proper place in order to see these get +responses in some location of space + + align:start position:0% +responses in some location of space + + + align:start position:0% +responses in some location of space +anywhere you put these electrodes in the + + align:start position:0% +anywhere you put these electrodes in the + + + align:start position:0% +anywhere you put these electrodes in the +hippocampus you're gonna get a certain + + align:start position:0% +hippocampus you're gonna get a certain + + + align:start position:0% +hippocampus you're gonna get a certain +fraction general about thirty percent of + + align:start position:0% +fraction general about thirty percent of + + + align:start position:0% +fraction general about thirty percent of +the cells will respond in a given + + align:start position:0% +the cells will respond in a given + + + align:start position:0% +the cells will respond in a given +environment and this is what those + + align:start position:0% +environment and this is what those + + + align:start position:0% +environment and this is what those +responses look like I won't go through + + align:start position:0% +responses look like I won't go through + + + align:start position:0% +responses look like I won't go through +the technical details but needless to + + align:start position:0% +the technical details but needless to + + + align:start position:0% +the technical details but needless to +say this just shows how of + + align:start position:0% +say this just shows how of + + + align:start position:0% +say this just shows how of +dance action potentials that are + + align:start position:0% +dance action potentials that are + + + align:start position:0% +dance action potentials that are +detected in here you see a voltage trace + + align:start position:0% +detected in here you see a voltage trace + + + align:start position:0% +detected in here you see a voltage trace +you pick out the amplitude of these of + + align:start position:0% +you pick out the amplitude of these of + + + align:start position:0% +you pick out the amplitude of these of +these little voltage transients + + align:start position:0% +these little voltage transients + + + align:start position:0% +these little voltage transients +generated by action potentials in the + + align:start position:0% +generated by action potentials in the + + + align:start position:0% +generated by action potentials in the +cells you plot the amplitude across + + align:start position:0% +cells you plot the amplitude across + + + align:start position:0% +cells you plot the amplitude across +these different channels in this way + + align:start position:0% +these different channels in this way + + + align:start position:0% +these different channels in this way +each point is an action potential and + + align:start position:0% +each point is an action potential and + + + align:start position:0% +each point is an action potential and +what you see is that the amplitudes will + + align:start position:0% +what you see is that the amplitudes will + + + align:start position:0% +what you see is that the amplitudes will +cluster that in a way that reflect the + + align:start position:0% +cluster that in a way that reflect the + + + align:start position:0% +cluster that in a way that reflect the +relative position or location of cells + + align:start position:0% +relative position or location of cells + + + align:start position:0% +relative position or location of cells +the sources relative to these wires with + + align:start position:0% +the sources relative to these wires with + + + align:start position:0% +the sources relative to these wires with +the bit using the basic principle that + + align:start position:0% +the bit using the basic principle that + + + align:start position:0% +the bit using the basic principle that +if you're closer to a wire the signals + + align:start position:0% +if you're closer to a wire the signals + + + align:start position:0% +if you're closer to a wire the signals +gonna get stronger so amplitude is + + align:start position:0% +gonna get stronger so amplitude is + + + align:start position:0% +gonna get stronger so amplitude is +essentially inversely related to + + align:start position:0% +essentially inversely related to + + + align:start position:0% +essentially inversely related to +distance so with this so here this is + + align:start position:0% +distance so with this so here this is + + + align:start position:0% +distance so with this so here this is +the amplitude of an action potential + + align:start position:0% +the amplitude of an action potential + + + align:start position:0% +the amplitude of an action potential +plot across two channels these points + + align:start position:0% +plot across two channels these points + + + align:start position:0% +plot across two channels these points +are large on channel one small on + + align:start position:0% +are large on channel one small on + + + align:start position:0% +are large on channel one small on +Channel two that means it's close to + + align:start position:0% +Channel two that means it's close to + + + align:start position:0% +Channel two that means it's close to +channel one far from channel two and + + align:start position:0% +channel one far from channel two and + + + align:start position:0% +channel one far from channel two and +then different cells will have different + + align:start position:0% +then different cells will have different + + + align:start position:0% +then different cells will have different +relations this will be large on channel + + align:start position:0% +relations this will be large on channel + + + align:start position:0% +relations this will be large on channel +two small on channel 1 etc so you can + + align:start position:0% +two small on channel 1 etc so you can + + + align:start position:0% +two small on channel 1 etc so you can +figure out where these cells are in + + align:start position:0% +figure out where these cells are in + + + align:start position:0% +figure out where these cells are in +space means you can record lots of pick + + align:start position:0% +space means you can record lots of pick + + + align:start position:0% +space means you can record lots of pick +out lots of cells from in this case + + align:start position:0% +out lots of cells from in this case + + + align:start position:0% +out lots of cells from in this case +maybe 12 to 18 electrodes can give you + + align:start position:0% +maybe 12 to 18 electrodes can give you + + + align:start position:0% +maybe 12 to 18 electrodes can give you +50 to 100 or more cells and then looking + + align:start position:0% +50 to 100 or more cells and then looking + + + align:start position:0% +50 to 100 or more cells and then looking +at the activity of those cells in a + + align:start position:0% +at the activity of those cells in a + + + align:start position:0% +at the activity of those cells in a +simple box this is just a little box one + + align:start position:0% +simple box this is just a little box one + + + align:start position:0% +simple box this is just a little box one +wall removed little salient cues your + + align:start position:0% +wall removed little salient cues your + + + align:start position:0% +wall removed little salient cues your +simple architectural design nice clean + + align:start position:0% +simple architectural design nice clean + + + align:start position:0% +simple architectural design nice clean +simple what you get is kind of clean + + align:start position:0% +simple what you get is kind of clean + + + align:start position:0% +simple what you get is kind of clean +simple mapping of spatial locations into + + align:start position:0% +simple mapping of spatial locations into + + + align:start position:0% +simple mapping of spatial locations into +these neuro responses so each one of + + align:start position:0% +these neuro responses so each one of + + + align:start position:0% +these neuro responses so each one of +these panels represents the activity of + + align:start position:0% +these panels represents the activity of + + + align:start position:0% +these panels represents the activity of +individual cells so this is about 80 + + align:start position:0% +individual cells so this is about 80 + + + align:start position:0% +individual cells so this is about 80 +simultaneous they recorded cells the + + align:start position:0% +simultaneous they recorded cells the + + + align:start position:0% +simultaneous they recorded cells the +color or the heat map indicates the the + + align:start position:0% +color or the heat map indicates the the + + + align:start position:0% +color or the heat map indicates the the +firing rate of these individual cells + + align:start position:0% +firing rate of these individual cells + + + align:start position:0% +firing rate of these individual cells +red indicates high firing rate blue + + align:start position:0% +red indicates high firing rate blue + + + align:start position:0% +red indicates high firing rate blue +indicates no firing so this is a + + align:start position:0% +indicates no firing so this is a + + + align:start position:0% +indicates no firing so this is a +top-down view of that box so this cell + + align:start position:0% +top-down view of that box so this cell + + + align:start position:0% +top-down view of that box so this cell +for instance when the animal is + + align:start position:0% +for instance when the animal is + + + align:start position:0% +for instance when the animal is +wandering around in the box the cell is + + align:start position:0% +wandering around in the box the cell is + + + align:start position:0% +wandering around in the box the cell is +silent and all the blue areas and what + + align:start position:0% +silent and all the blue areas and what + + + align:start position:0% +silent and all the blue areas and what +goes in the lower right-hand corner the + + align:start position:0% +goes in the lower right-hand corner the + + + align:start position:0% +goes in the lower right-hand corner the +cell fires vigorously so silent fires + + align:start position:0% +cell fires vigorously so silent fires + + + align:start position:0% +cell fires vigorously so silent fires +vigorously this one fires on + + align:start position:0% +vigorously this one fires on + + + align:start position:0% +vigorously this one fires on +left-hand wall this one also fires in + + align:start position:0% +left-hand wall this one also fires in + + + align:start position:0% +left-hand wall this one also fires in +the lower right hand side so again this + + align:start position:0% +the lower right hand side so again this + + + align:start position:0% +the lower right hand side so again this +sort of points out this the + + align:start position:0% +sort of points out this the + + + align:start position:0% +sort of points out this the +combinatorial nature of this spatial + + align:start position:0% +combinatorial nature of this spatial + + + align:start position:0% +combinatorial nature of this spatial +representation that is that if the + + align:start position:0% +representation that is that if the + + + align:start position:0% +representation that is that if the +animals in the lower right hand corner + + align:start position:0% +animals in the lower right hand corner + + + align:start position:0% +animals in the lower right hand corner +of this particular box you'll see will + + align:start position:0% +of this particular box you'll see will + + + align:start position:0% +of this particular box you'll see will +get these two cells to fire if I take + + align:start position:0% +get these two cells to fire if I take + + + align:start position:0% +get these two cells to fire if I take +the animal I put it into a different box + + align:start position:0% +the animal I put it into a different box + + + align:start position:0% +the animal I put it into a different box +all of these responses will be scrambled + + align:start position:0% +all of these responses will be scrambled + + + align:start position:0% +all of these responses will be scrambled +up there's nothing that says this cell + + align:start position:0% +up there's nothing that says this cell + + + align:start position:0% +up there's nothing that says this cell +will fire in the lower right hand corner + + align:start position:0% +will fire in the lower right hand corner + + + align:start position:0% +will fire in the lower right hand corner +of another box and certainly even if it + + align:start position:0% +of another box and certainly even if it + + + align:start position:0% +of another box and certainly even if it +does fire in the lower right hand corner + + align:start position:0% +does fire in the lower right hand corner + + + align:start position:0% +does fire in the lower right hand corner +this other cell isn't going to fire + + align:start position:0% +this other cell isn't going to fire + + + align:start position:0% +this other cell isn't going to fire +along with it and at any given location + + align:start position:0% +along with it and at any given location + + + align:start position:0% +along with it and at any given location +they're roughly 1 to 5 percent of the + + align:start position:0% +they're roughly 1 to 5 percent of the + + + align:start position:0% +they're roughly 1 to 5 percent of the +cells that are firing so at any given + + align:start position:0% +cells that are firing so at any given + + + align:start position:0% +cells that are firing so at any given +location they're about maybe 5,000 cells + + align:start position:0% +location they're about maybe 5,000 cells + + + align:start position:0% +location they're about maybe 5,000 cells +in the hippocampus that are active so + + align:start position:0% +in the hippocampus that are active so + + + align:start position:0% +in the hippocampus that are active so +the location the unique location and + + align:start position:0% +the location the unique location and + + + align:start position:0% +the location the unique location and +unique contexts and environments can be + + align:start position:0% +unique contexts and environments can be + + + align:start position:0% +unique contexts and environments can be +conveyed across a pattern of a unique + + align:start position:0% +conveyed across a pattern of a unique + + + align:start position:0% +conveyed across a pattern of a unique +pattern of about 5,000 cells out of 100 + + align:start position:0% +pattern of about 5,000 cells out of 100 + + + align:start position:0% +pattern of about 5,000 cells out of 100 +or 200 thousand cells so there's large + + align:start position:0% +or 200 thousand cells so there's large + + + align:start position:0% +or 200 thousand cells so there's large +combinatorial space and which one can + + align:start position:0% +combinatorial space and which one can + + + align:start position:0% +combinatorial space and which one can +represent uniquely unique locations or + + align:start position:0% +represent uniquely unique locations or + + + align:start position:0% +represent uniquely unique locations or +potentially even unique experiences + + align:start position:0% +potentially even unique experiences + + + align:start position:0% +potentially even unique experiences +within different locations you see that + + align:start position:0% +within different locations you see that + + + align:start position:0% +within different locations you see that +many cells are silent on average about + + align:start position:0% +many cells are silent on average about + + + align:start position:0% +many cells are silent on average about +30 percent of the cells respond in a + + align:start position:0% +30 percent of the cells respond in a + + + align:start position:0% +30 percent of the cells respond in a +given environment these silent cells as + + align:start position:0% +given environment these silent cells as + + + align:start position:0% +given environment these silent cells as +we'll see they can be detected when the + + align:start position:0% +we'll see they can be detected when the + + + align:start position:0% +we'll see they can be detected when the +animals are not in a running around or + + align:start position:0% +animals are not in a running around or + + + align:start position:0% +animals are not in a running around or +experiencing space but when they're + + align:start position:0% +experiencing space but when they're + + + align:start position:0% +experiencing space but when they're +asleep or these other offline states + + align:start position:0% +asleep or these other offline states + + + align:start position:0% +asleep or these other offline states +when the hippocampus is actually + + align:start position:0% +when the hippocampus is actually + + + align:start position:0% +when the hippocampus is actually +evaluating thinking about other stuff + + align:start position:0% +evaluating thinking about other stuff + + + align:start position:0% +evaluating thinking about other stuff +and we'll talk about it about that a bit + + align:start position:0% +and we'll talk about it about that a bit + + + align:start position:0% +and we'll talk about it about that a bit +and then here you can also see a small + + align:start position:0% +and then here you can also see a small + + + align:start position:0% +and then here you can also see a small +number of these cells in this case you + + align:start position:0% +number of these cells in this case you + + + align:start position:0% +number of these cells in this case you +know about five to ten percent of these + + align:start position:0% +know about five to ten percent of these + + + align:start position:0% +know about five to ten percent of these +cells seem to have elevated firing rate + + align:start position:0% +cells seem to have elevated firing rate + + + align:start position:0% +cells seem to have elevated firing rate +across the entire space is there + + align:start position:0% +across the entire space is there + + + align:start position:0% +across the entire space is there +actually a different class of neurons + + align:start position:0% +actually a different class of neurons + + + align:start position:0% +actually a different class of neurons +these are excitatory neurons these are + + align:start position:0% +these are excitatory neurons these are + + + align:start position:0% +these are excitatory neurons these are +inhibitory neurons inhibition the idea + + align:start position:0% +inhibitory neurons inhibition the idea + + + align:start position:0% +inhibitory neurons inhibition the idea +that you have circuits that that can + + align:start position:0% +that you have circuits that that can + + + align:start position:0% +that you have circuits that that can +both excite and inhibit and that this is + + align:start position:0% +both excite and inhibit and that this is + + + align:start position:0% +both excite and inhibit and that this is +used as a because as a circuit property + + align:start position:0% +used as a because as a circuit property + + + align:start position:0% +used as a because as a circuit property +to to sculpt computation is something + + align:start position:0% +to to sculpt computation is something + + + align:start position:0% +to to sculpt computation is something +that will also discuss so this balance + + align:start position:0% +that will also discuss so this balance + + + align:start position:0% +that will also discuss so this balance +between excitation as kind of a circuit + + align:start position:0% +between excitation as kind of a circuit + + + align:start position:0% +between excitation as kind of a circuit +principle that's used inhibitory cells + + align:start position:0% +principle that's used inhibitory cells + + + align:start position:0% +principle that's used inhibitory cells +I can fire all over the place they're + + align:start position:0% +I can fire all over the place they're + + + align:start position:0% +I can fire all over the place they're +not really communicating information + + align:start position:0% +not really communicating information + + + align:start position:0% +not really communicating information +they're really modulating the processing + + align:start position:0% +they're really modulating the processing + + + align:start position:0% +they're really modulating the processing +of information and another property of + + align:start position:0% +of information and another property of + + + align:start position:0% +of information and another property of +these cells that that O'Keefe termed + + align:start position:0% +these cells that that O'Keefe termed + + + align:start position:0% +these cells that that O'Keefe termed +play cells is that when animals are + + align:start position:0% +play cells is that when animals are + + + align:start position:0% +play cells is that when animals are +constrained to move along along these + + align:start position:0% +constrained to move along along these + + + align:start position:0% +constrained to move along along these +limited paths in this case this is a + + align:start position:0% +limited paths in this case this is a + + + align:start position:0% +limited paths in this case this is a +linear track as we refer to it it's like + + align:start position:0% +linear track as we refer to it it's like + + + align:start position:0% +linear track as we refer to it it's like +a little corridor animals moving down + + align:start position:0% +a little corridor animals moving down + + + align:start position:0% +a little corridor animals moving down +this corridor when they move down a + + align:start position:0% +this corridor when they move down a + + + align:start position:0% +this corridor when they move down a +corridor the cells don't only fire where + + align:start position:0% +corridor the cells don't only fire where + + + align:start position:0% +corridor the cells don't only fire where +the animal is but also in the direction + + align:start position:0% +the animal is but also in the direction + + + align:start position:0% +the animal is but also in the direction +of this going and so this is the first + + align:start position:0% +of this going and so this is the first + + + align:start position:0% +of this going and so this is the first +indication these cells are not just + + align:start position:0% +indication these cells are not just + + + align:start position:0% +indication these cells are not just +again it's not just a GPS that's nothing + + align:start position:0% +again it's not just a GPS that's nothing + + + align:start position:0% +again it's not just a GPS that's nothing +that's telling you where you are it's at + + align:start position:0% +that's telling you where you are it's at + + + align:start position:0% +that's telling you where you are it's at +least telling you where you're going + + align:start position:0% +least telling you where you're going + + + align:start position:0% +least telling you where you're going +maybe what you're doing so here if I + + align:start position:0% +maybe what you're doing so here if I + + + align:start position:0% +maybe what you're doing so here if I +look at this yellow cell I can tell that + + align:start position:0% +look at this yellow cell I can tell that + + + align:start position:0% +look at this yellow cell I can tell that +the animal is not only in this location + + align:start position:0% +the animal is not only in this location + + + align:start position:0% +the animal is not only in this location +but it's moving down this this linear + + align:start position:0% +but it's moving down this this linear + + + align:start position:0% +but it's moving down this this linear +track in this direction so there's like + + align:start position:0% +track in this direction so there's like + + + align:start position:0% +track in this direction so there's like +there's going to be a unique sequence + + align:start position:0% +there's going to be a unique sequence + + + align:start position:0% +there's going to be a unique sequence +when the animal walks along this path + + align:start position:0% +when the animal walks along this path + + + align:start position:0% +when the animal walks along this path +yellow cell red cell green cells so the + + align:start position:0% +yellow cell red cell green cells so the + + + align:start position:0% +yellow cell red cell green cells so the +different cells are color coded here so + + align:start position:0% +different cells are color coded here so + + + align:start position:0% +different cells are color coded here so +if you look over time you'll see that + + align:start position:0% +if you look over time you'll see that + + + align:start position:0% +if you look over time you'll see that +there will be a unique sequence of + + align:start position:0% +there will be a unique sequence of + + + align:start position:0% +there will be a unique sequence of +activity in the hippocampus that + + align:start position:0% +activity in the hippocampus that + + + align:start position:0% +activity in the hippocampus that +reflects the animals actual behavior + + align:start position:0% +reflects the animals actual behavior + + + align:start position:0% +reflects the animals actual behavior +experienced in that space so here this + + align:start position:0% +experienced in that space so here this + + + align:start position:0% +experienced in that space so here this +is just a little movie that shows raw + + align:start position:0% +is just a little movie that shows raw + + + align:start position:0% +is just a little movie that shows raw +this is this is what you would actually + + align:start position:0% +this is this is what you would actually + + + align:start position:0% +this is this is what you would actually +see if you're running experiment this + + align:start position:0% +see if you're running experiment this + + + align:start position:0% +see if you're running experiment this +little top-down view the green circle + + align:start position:0% +little top-down view the green circle + + + align:start position:0% +little top-down view the green circle +shows just highlights where the rat + + align:start position:0% +shows just highlights where the rat + + + align:start position:0% +shows just highlights where the rat +actually is the color coding these are + + align:start position:0% +actually is the color coding these are + + + align:start position:0% +actually is the color coding these are +the cells that we're picking up over + + align:start position:0% +the cells that we're picking up over + + + align:start position:0% +the cells that we're picking up over +here this is this is data as it would be + + align:start position:0% +here this is this is data as it would be + + + align:start position:0% +here this is this is data as it would be +coming out of the setup so you see this + + align:start position:0% +coming out of the setup so you see this + + + align:start position:0% +coming out of the setup so you see this +light blue cell fires here the dark blue + + align:start position:0% +light blue cell fires here the dark blue + + + align:start position:0% +light blue cell fires here the dark blue +cell fires here dark blue cell light + + align:start position:0% +cell fires here dark blue cell light + + + align:start position:0% +cell fires here dark blue cell light +blue cell so this is the spatial firing + + align:start position:0% +blue cell so this is the spatial firing + + + align:start position:0% +blue cell so this is the spatial firing +property place cells and now so the + + align:start position:0% +property place cells and now so the + + + align:start position:0% +property place cells and now so the +animal is stopped and one thing even + + align:start position:0% +animal is stopped and one thing even + + + align:start position:0% +animal is stopped and one thing even +notice you so lots of activity and + + align:start position:0% +notice you so lots of activity and + + + align:start position:0% +notice you so lots of activity and +animals stop there there was this big + + align:start position:0% +animals stop there there was this big + + + align:start position:0% +animals stop there there was this big +burst of activity he'll stop again a + + align:start position:0% +burst of activity he'll stop again a + + + align:start position:0% +burst of activity he'll stop again a +little bit later he's moving + + align:start position:0% + + + + align:start position:0% + +and he's moving if you listen carefully + + align:start position:0% +and he's moving if you listen carefully + + + align:start position:0% +and he's moving if you listen carefully +you'll hear the business background + + align:start position:0% +you'll hear the business background + + + align:start position:0% +you'll hear the business background +rhythm there's a modulation this kind of + + align:start position:0% +rhythm there's a modulation this kind of + + + align:start position:0% +rhythm there's a modulation this kind of +background modulation activity which is + + align:start position:0% +background modulation activity which is + + + align:start position:0% +background modulation activity which is +associated with locomotion so they're + + align:start position:0% +associated with locomotion so they're + + + align:start position:0% +associated with locomotion so they're +really two modes you're actively engaged + + align:start position:0% +really two modes you're actively engaged + + + align:start position:0% +really two modes you're actively engaged +in where you're taking information in + + align:start position:0% +in where you're taking information in + + + align:start position:0% +in where you're taking information in +you get this rhythm when you're + + align:start position:0% +you get this rhythm when you're + + + align:start position:0% +you get this rhythm when you're +inattentive not engaged not taking + + align:start position:0% +inattentive not engaged not taking + + + align:start position:0% +inattentive not engaged not taking +information in but internally evaluate + + align:start position:0% +information in but internally evaluate + + + align:start position:0% +information in but internally evaluate +it the rhythm goes away and it's + + align:start position:0% +it the rhythm goes away and it's + + + align:start position:0% +it the rhythm goes away and it's +replaced by these sort of bursts of + + align:start position:0% +replaced by these sort of bursts of + + + align:start position:0% +replaced by these sort of bursts of +activity and so these two modes active + + align:start position:0% +activity and so these two modes active + + + align:start position:0% +activity and so these two modes active +attentive you're processing information + + align:start position:0% +attentive you're processing information + + + align:start position:0% +attentive you're processing information +coming in inattentive you're evaluating + + align:start position:0% +coming in inattentive you're evaluating + + + align:start position:0% +coming in inattentive you're evaluating +informations it's Jordan taking you're + + align:start position:0% +informations it's Jordan taking you're + + + align:start position:0% +informations it's Jordan taking you're +thinking about stuff can be reflected in + + align:start position:0% +thinking about stuff can be reflected in + + + align:start position:0% +thinking about stuff can be reflected in +these two characteristic modes which you + + align:start position:0% +these two characteristic modes which you + + + align:start position:0% +these two characteristic modes which you +can literally you can hear I mean here + + align:start position:0% +can literally you can hear I mean here + + + align:start position:0% +can literally you can hear I mean here +the difference between the two obviously + + align:start position:0% +the difference between the two obviously + + + align:start position:0% +the difference between the two obviously +I've been listening these things for a + + align:start position:0% +I've been listening these things for a + + + align:start position:0% +I've been listening these things for a +long time so it's very easy for me to + + align:start position:0% +long time so it's very easy for me to + + + align:start position:0% +long time so it's very easy for me to +pick up you might be harder for you but + + align:start position:0% +pick up you might be harder for you but + + + align:start position:0% +pick up you might be harder for you but +you know you listen to it a little bit + + align:start position:0% +you know you listen to it a little bit + + + align:start position:0% +you know you listen to it a little bit +and it's very easy to distinguish these + + align:start position:0% +and it's very easy to distinguish these + + + align:start position:0% +and it's very easy to distinguish these +two different brain modes so this can be + + align:start position:0% +two different brain modes so this can be + + + align:start position:0% +two different brain modes so this can be +another view of that data it's the same + + align:start position:0% +another view of that data it's the same + + + align:start position:0% +another view of that data it's the same +data only now instead of showing you the + + align:start position:0% +data only now instead of showing you the + + + align:start position:0% +data only now instead of showing you the +raw data whereas the you know where is + + align:start position:0% +raw data whereas the you know where is + + + align:start position:0% +raw data whereas the you know where is +the firing and there's one thing about + + align:start position:0% +the firing and there's one thing about + + + align:start position:0% +the firing and there's one thing about +you know this correlate it that's so + + align:start position:0% +you know this correlate it that's so + + + align:start position:0% +you know this correlate it that's so +compelling I mean that was literally raw + + align:start position:0% +compelling I mean that was literally raw + + + align:start position:0% +compelling I mean that was literally raw +data that's as it was coming out there's + + align:start position:0% +data that's as it was coming out there's + + + align:start position:0% +data that's as it was coming out there's +like there's no processing at all and + + align:start position:0% +like there's no processing at all and + + + align:start position:0% +like there's no processing at all and +you could see the coil you can see the + + align:start position:0% +you could see the coil you can see the + + + align:start position:0% +you could see the coil you can see the +spatial correlate which tells you you + + align:start position:0% +spatial correlate which tells you you + + + align:start position:0% +spatial correlate which tells you you +know this is not something that requires + + align:start position:0% +know this is not something that requires + + + align:start position:0% +know this is not something that requires +you know I have to do you know sort of + + align:start position:0% +you know I have to do you know sort of + + + align:start position:0% +you know I have to do you know sort of +you know multiple multiple regressions + + align:start position:0% +you know multiple multiple regressions + + + align:start position:0% +you know multiple multiple regressions +and you know show you all of the you + + align:start position:0% +and you know show you all of the you + + + align:start position:0% +and you know show you all of the you +know the you know give you some sort of + + align:start position:0% +know the you know give you some sort of + + + align:start position:0% +know the you know give you some sort of +you know statistical confidence that + + align:start position:0% +you know statistical confidence that + + + align:start position:0% +you know statistical confidence that +this is what the peak amp is doing you + + align:start position:0% +this is what the peak amp is doing you + + + align:start position:0% +this is what the peak amp is doing you +can literally see it in individual cells + + align:start position:0% +can literally see it in individual cells + + + align:start position:0% +can literally see it in individual cells +the spatial correlate is extremely + + align:start position:0% +the spatial correlate is extremely + + + align:start position:0% +the spatial correlate is extremely +robust compelling and consistent those + + align:start position:0% +robust compelling and consistent those + + + align:start position:0% +robust compelling and consistent those +cells weren't selected if you record any + + align:start position:0% +cells weren't selected if you record any + + + align:start position:0% +cells weren't selected if you record any +of the cells in the hippocampus they're + + align:start position:0% +of the cells in the hippocampus they're + + + align:start position:0% +of the cells in the hippocampus they're +all doing that the estimate is that over + + align:start position:0% +all doing that the estimate is that over + + + align:start position:0% +all doing that the estimate is that over +95% of the cells that you can record the + + align:start position:0% +95% of the cells that you can record the + + + align:start position:0% +95% of the cells that you can record the +rodent hippocampus will have these + + align:start position:0% +rodent hippocampus will have these + + + align:start position:0% +rodent hippocampus will have these +spatial properties so it's really a + + align:start position:0% +spatial properties so it's really a + + + align:start position:0% +spatial properties so it's really a +fundamental property of of this memory + + align:start position:0% +fundamental property of of this memory + + + align:start position:0% +fundamental property of of this memory +system so it's the same data except now + + align:start position:0% +system so it's the same data except now + + + align:start position:0% +system so it's the same data except now +instead of showing the spiking we're + + align:start position:0% +instead of showing the spiking we're + + + align:start position:0% +instead of showing the spiking we're +going to use this sort of a simple + + align:start position:0% +going to use this sort of a simple + + + align:start position:0% +going to use this sort of a simple +Bayesian estimation algorithm to ask the + + align:start position:0% +Bayesian estimation algorithm to ask the + + + align:start position:0% +Bayesian estimation algorithm to ask the +question okay if if we know which + + align:start position:0% +question okay if if we know which + + + align:start position:0% +question okay if if we know which +cells are firing can we guess the + + align:start position:0% +cells are firing can we guess the + + + align:start position:0% +cells are firing can we guess the +location that the animal would likely be + + align:start position:0% +location that the animal would likely be + + + align:start position:0% +location that the animal would likely be +that is if we know the firing as a + + align:start position:0% +that is if we know the firing as a + + + align:start position:0% +that is if we know the firing as a +function of location we can use so + + align:start position:0% +function of location we can use so + + + align:start position:0% +function of location we can use so +Bayesian inference to guess that + + align:start position:0% +Bayesian inference to guess that + + + align:start position:0% +Bayesian inference to guess that +probably have a location given firing + + align:start position:0% +probably have a location given firing + + + align:start position:0% +probably have a location given firing +and that's we're gonna do here just + + align:start position:0% +and that's we're gonna do here just + + + align:start position:0% +and that's we're gonna do here just +asking if we know which cells are firing + + align:start position:0% +asking if we know which cells are firing + + + align:start position:0% +asking if we know which cells are firing +for instance if the blue cell is firing + + align:start position:0% +for instance if the blue cell is firing + + + align:start position:0% +for instance if the blue cell is firing +you would say all the cell the animals + + align:start position:0% +you would say all the cell the animals + + + align:start position:0% +you would say all the cell the animals +probably over here so recording across + + align:start position:0% +probably over here so recording across + + + align:start position:0% +probably over here so recording across +looking at pattern cross many cells and + + align:start position:0% +looking at pattern cross many cells and + + + align:start position:0% +looking at pattern cross many cells and +they were coming up every hundred + + align:start position:0% +they were coming up every hundred + + + align:start position:0% +they were coming up every hundred +milliseconds we're coming up with a + + align:start position:0% +milliseconds we're coming up with a + + + align:start position:0% +milliseconds we're coming up with a +probability that that pattern could have + + align:start position:0% +probability that that pattern could have + + + align:start position:0% +probability that that pattern could have +occurred if the animal is at any + + align:start position:0% +occurred if the animal is at any + + + align:start position:0% +occurred if the animal is at any +location on this track and the + + align:start position:0% +location on this track and the + + + align:start position:0% +location on this track and the +probability is going to be shown by + + align:start position:0% +probability is going to be shown by + + + align:start position:0% +probability is going to be shown by +triangle big triangle means high + + align:start position:0% +triangle big triangle means high + + + align:start position:0% +triangle big triangle means high +probability and what you'll see is when + + align:start position:0% +probability and what you'll see is when + + + align:start position:0% +probability and what you'll see is when +we do this estimation when the animals + + align:start position:0% +we do this estimation when the animals + + + align:start position:0% +we do this estimation when the animals +moving you see the triangle the triangle + + align:start position:0% +moving you see the triangle the triangle + + + align:start position:0% +moving you see the triangle the triangle +basically the triangles are only signai + + align:start position:0% +basically the triangles are only signai + + + align:start position:0% +basically the triangles are only signai +only you know highly probable when the + + align:start position:0% +only you know highly probable when the + + + align:start position:0% +only you know highly probable when the +animal is actually moving when the + + align:start position:0% +animal is actually moving when the + + + align:start position:0% +animal is actually moving when the +animal and only at the location that the + + align:start position:0% +animal and only at the location that the + + + align:start position:0% +animal and only at the location that the +animal is so hippocampus is centrally a + + align:start position:0% +animal is so hippocampus is centrally a + + + align:start position:0% +animal is so hippocampus is centrally a +couple representations tracking location + + align:start position:0% +couple representations tracking location + + + align:start position:0% +couple representations tracking location +the animal notice when the animal stops + + align:start position:0% +the animal notice when the animal stops + + + align:start position:0% +the animal notice when the animal stops +now if you listen so you heard the + + align:start position:0% +now if you listen so you heard the + + + align:start position:0% +now if you listen so you heard the +bursts and you look at the triangle but + + align:start position:0% +bursts and you look at the triangle but + + + align:start position:0% +bursts and you look at the triangle but +animal stops triangle no longer + + align:start position:0% +animal stops triangle no longer + + + align:start position:0% +animal stops triangle no longer +corresponds where the animal is in fact + + align:start position:0% +corresponds where the animal is in fact + + + align:start position:0% +corresponds where the animal is in fact +you can get the burst you see the + + align:start position:0% +you can get the burst you see the + + + align:start position:0% +you can get the burst you see the +triangle jumping around the track so + + align:start position:0% +triangle jumping around the track so + + + align:start position:0% +triangle jumping around the track so +again to these two modes and the + + align:start position:0% +again to these two modes and the + + + align:start position:0% +again to these two modes and the +representations have these two + + align:start position:0% +representations have these two + + + align:start position:0% +representations have these two +properties moving oscillation track + + align:start position:0% +properties moving oscillation track + + + align:start position:0% +properties moving oscillation track +current location stopping oscillation + + align:start position:0% +current location stopping oscillation + + + align:start position:0% +current location stopping oscillation +goes away representation now it jumps + + align:start position:0% +goes away representation now it jumps + + + align:start position:0% +goes away representation now it jumps +across the track and interestingly these + + align:start position:0% +across the track and interestingly these + + + align:start position:0% +across the track and interestingly these +little bursts like that also occur not + + align:start position:0% +little bursts like that also occur not + + + align:start position:0% +little bursts like that also occur not +just when the animal stops briefly but + + align:start position:0% +just when the animal stops briefly but + + + align:start position:0% +just when the animal stops briefly but +when it actually goes to sleep so here + + align:start position:0% +when it actually goes to sleep so here + + + align:start position:0% +when it actually goes to sleep so here +in the inset this is the animal now it's + + align:start position:0% +in the inset this is the animal now it's + + + align:start position:0% +in the inset this is the animal now it's +been taken off the track altogether it's + + align:start position:0% +been taken off the track altogether it's + + + align:start position:0% +been taken off the track altogether it's +just sitting in a little box somewhere + + align:start position:0% +just sitting in a little box somewhere + + + align:start position:0% +just sitting in a little box somewhere +else it's curled up and it's asleep you + + align:start position:0% +else it's curled up and it's asleep you + + + align:start position:0% +else it's curled up and it's asleep you +get these same bursts and when you + + align:start position:0% +get these same bursts and when you + + + align:start position:0% +get these same bursts and when you +decode activity you find you can decode + + align:start position:0% +decode activity you find you can decode + + + align:start position:0% +decode activity you find you can decode +the position on the track and if you + + align:start position:0% +the position on the track and if you + + + align:start position:0% +the position on the track and if you +look carefully you see that the position + + align:start position:0% +look carefully you see that the position + + + align:start position:0% +look carefully you see that the position +actually follows a sequence of + + align:start position:0% +actually follows a sequence of + + + align:start position:0% +actually follows a sequence of +trajectory along the track and and we'll + + align:start position:0% +trajectory along the track and and we'll + + + align:start position:0% +trajectory along the track and and we'll +go into that a little bit + + align:start position:0% +go into that a little bit + + + align:start position:0% +go into that a little bit +detail so you think of there being these + + align:start position:0% +detail so you think of there being these + + + align:start position:0% +detail so you think of there being these +two states the offline and the online in + + align:start position:0% +two states the offline and the online in + + + align:start position:0% +two states the offline and the online in +the online with animals moving the + + align:start position:0% +the online with animals moving the + + + align:start position:0% +the online with animals moving the +characteristic mode of active activity + + align:start position:0% +characteristic mode of active activity + + + align:start position:0% +characteristic mode of active activity +in the hippocampus there's an + + align:start position:0% +in the hippocampus there's an + + + align:start position:0% +in the hippocampus there's an +oscillatory mode described is the theta + + align:start position:0% +oscillatory mode described is the theta + + + align:start position:0% +oscillatory mode described is the theta +rhythm which is this 10 Hertz + + align:start position:0% +rhythm which is this 10 Hertz + + + align:start position:0% +rhythm which is this 10 Hertz +oscillation when the animal stops and + + align:start position:0% +oscillation when the animal stops and + + + align:start position:0% +oscillation when the animal stops and +becomes quiet Numa mobile within about + + align:start position:0% +becomes quiet Numa mobile within about + + + align:start position:0% +becomes quiet Numa mobile within about +half a second oscillation goes away and + + align:start position:0% +half a second oscillation goes away and + + + align:start position:0% +half a second oscillation goes away and +is replaced by these large transient a + + align:start position:0% +is replaced by these large transient a + + + align:start position:0% +is replaced by these large transient a +periodic events these so-called sharp + + align:start position:0% +periodic events these so-called sharp + + + align:start position:0% +periodic events these so-called sharp +waves because in the the extracellular + + align:start position:0% +waves because in the the extracellular + + + align:start position:0% +waves because in the the extracellular +electrical field that you measure you + + align:start position:0% +electrical field that you measure you + + + align:start position:0% +electrical field that you measure you +see these large deflections and then if + + align:start position:0% +see these large deflections and then if + + + align:start position:0% +see these large deflections and then if +you zoom in I also show you shortly + + align:start position:0% +you zoom in I also show you shortly + + + align:start position:0% +you zoom in I also show you shortly +you can actually see these very high + + align:start position:0% +you can actually see these very high + + + align:start position:0% +you can actually see these very high +frequency oscillations about one to two + + align:start position:0% +frequency oscillations about one to two + + + align:start position:0% +frequency oscillations about one to two +hundred Hertz riding on top of that + + align:start position:0% +hundred Hertz riding on top of that + + + align:start position:0% +hundred Hertz riding on top of that +these are referred to as ripples and + + align:start position:0% +these are referred to as ripples and + + + align:start position:0% +these are referred to as ripples and +this is a term that your GU sake + + align:start position:0% +this is a term that your GU sake + + + align:start position:0% +this is a term that your GU sake +came up with he described this sharp + + align:start position:0% +came up with he described this sharp + + + align:start position:0% +came up with he described this sharp +wave ripple activity it's corresponding + + align:start position:0% +wave ripple activity it's corresponding + + + align:start position:0% +wave ripple activity it's corresponding +to this offline state quiet wakeful and + + align:start position:0% +to this offline state quiet wakeful and + + + align:start position:0% +to this offline state quiet wakeful and +some sleep states so the first thing is + + align:start position:0% +some sleep states so the first thing is + + + align:start position:0% +some sleep states so the first thing is +just is to look at this oscillatory + + align:start position:0% +just is to look at this oscillatory + + + align:start position:0% +just is to look at this oscillatory +state so in the animals actually moving + + align:start position:0% +state so in the animals actually moving + + + align:start position:0% +state so in the animals actually moving +and I've already shown you the spatial + + align:start position:0% +and I've already shown you the spatial + + + align:start position:0% +and I've already shown you the spatial +Coral at these play cells but there's + + align:start position:0% +Coral at these play cells but there's + + + align:start position:0% +Coral at these play cells but there's +another property of these cells that + + align:start position:0% +another property of these cells that + + + align:start position:0% +another property of these cells that +O'Keefe also discovered but this was in + + align:start position:0% +O'Keefe also discovered but this was in + + + align:start position:0% +O'Keefe also discovered but this was in +early 1990s around 1991 and that is he + + align:start position:0% +early 1990s around 1991 and that is he + + + align:start position:0% +early 1990s around 1991 and that is he +noted if you actually look at the + + align:start position:0% +noted if you actually look at the + + + align:start position:0% +noted if you actually look at the +discharge of single spikes with respect + + align:start position:0% +discharge of single spikes with respect + + + align:start position:0% +discharge of single spikes with respect +to this oscillation first of all the + + align:start position:0% +to this oscillation first of all the + + + align:start position:0% +to this oscillation first of all the +spikes are actually phase locked and + + align:start position:0% +spikes are actually phase locked and + + + align:start position:0% +spikes are actually phase locked and +there was here spikes fire when the + + align:start position:0% +there was here spikes fire when the + + + align:start position:0% +there was here spikes fire when the +oscillation this theta rhythm is that + + align:start position:0% +oscillation this theta rhythm is that + + + align:start position:0% +oscillation this theta rhythm is that +its peak so the idea is that oscillation + + align:start position:0% +its peak so the idea is that oscillation + + + align:start position:0% +its peak so the idea is that oscillation +really reflects time varying + + align:start position:0% +really reflects time varying + + + align:start position:0% +really reflects time varying +excitability sometimes where the cells + + align:start position:0% +excitability sometimes where the cells + + + align:start position:0% +excitability sometimes where the cells +likely to fire other times when it's not + + align:start position:0% +likely to fire other times when it's not + + + align:start position:0% +likely to fire other times when it's not +and you can think of this oscillation in + + align:start position:0% +and you can think of this oscillation in + + + align:start position:0% +and you can think of this oscillation in +excitability as being an oscillation in + + align:start position:0% +excitability as being an oscillation in + + + align:start position:0% +excitability as being an oscillation in +relative excitability or inhibition so + + align:start position:0% +relative excitability or inhibition so + + + align:start position:0% +relative excitability or inhibition so +inhibition elevation is high it's low + + align:start position:0% +inhibition elevation is high it's low + + + align:start position:0% +inhibition elevation is high it's low +it's high is low when the inhibition is + + align:start position:0% +it's high is low when the inhibition is + + + align:start position:0% +it's high is low when the inhibition is +low cell fires when it's high cell + + align:start position:0% +low cell fires when it's high cell + + + align:start position:0% +low cell fires when it's high cell +doesn't fire so this is modulation + + align:start position:0% +doesn't fire so this is modulation + + + align:start position:0% +doesn't fire so this is modulation +excitability you see this here but he + + align:start position:0% +excitability you see this here but he + + + align:start position:0% +excitability you see this here but he +noted another thing + + align:start position:0% +noted another thing + + + align:start position:0% +noted another thing +that is if you look at the precise phase + + align:start position:0% +that is if you look at the precise phase + + + align:start position:0% +that is if you look at the precise phase +so here yes cells tend to fire kind of + + align:start position:0% +so here yes cells tend to fire kind of + + + align:start position:0% +so here yes cells tend to fire kind of +at the peak but here this is now over + + align:start position:0% +at the peak but here this is now over + + + align:start position:0% +at the peak but here this is now over +time but animal moving at constant + + align:start position:0% +time but animal moving at constant + + + align:start position:0% +time but animal moving at constant +velocity space and time are + + align:start position:0% +velocity space and time are + + + align:start position:0% +velocity space and time are +interchangeable so as an animal is + + align:start position:0% +interchangeable so as an animal is + + + align:start position:0% +interchangeable so as an animal is +moving through its place field the + + align:start position:0% +moving through its place field the + + + align:start position:0% +moving through its place field the +spikes start to fire earlier and earlier + + align:start position:0% +spikes start to fire earlier and earlier + + + align:start position:0% +spikes start to fire earlier and earlier +that is there's a phase code spatial + + align:start position:0% +that is there's a phase code spatial + + + align:start position:0% +that is there's a phase code spatial +location so you can tell based upon the + + align:start position:0% +location so you can tell based upon the + + + align:start position:0% +location so you can tell based upon the +relative phase whether the animal is + + align:start position:0% +relative phase whether the animal is + + + align:start position:0% +relative phase whether the animal is +just entering the field spikes fire late + + align:start position:0% +just entering the field spikes fire late + + + align:start position:0% +just entering the field spikes fire late +here close to the peak versus further + + align:start position:0% +here close to the peak versus further + + + align:start position:0% +here close to the peak versus further +into the field where they fire a little + + align:start position:0% +into the field where they fire a little + + + align:start position:0% +into the field where they fire a little +bit earlier there's a relationship + + align:start position:0% +bit earlier there's a relationship + + + align:start position:0% +bit earlier there's a relationship +between distance into the field and + + align:start position:0% +between distance into the field and + + + align:start position:0% +between distance into the field and +relative phase what he termed phase + + align:start position:0% +relative phase what he termed phase + + + align:start position:0% +relative phase what he termed phase +procession and this is a representation + + align:start position:0% +procession and this is a representation + + + align:start position:0% +procession and this is a representation +of that this is an actual data this is + + align:start position:0% +of that this is an actual data this is + + + align:start position:0% +of that this is an actual data this is +just a cartoon that illustrates the + + align:start position:0% +just a cartoon that illustrates the + + + align:start position:0% +just a cartoon that illustrates the +basic principle this is the idea that if + + align:start position:0% +basic principle this is the idea that if + + + align:start position:0% +basic principle this is the idea that if +I have a place cell if I look at the + + align:start position:0% +I have a place cell if I look at the + + + align:start position:0% +I have a place cell if I look at the +marginal distribution as a function of + + align:start position:0% +marginal distribution as a function of + + + align:start position:0% +marginal distribution as a function of +location this would be the place field + + align:start position:0% +location this would be the place field + + + align:start position:0% +location this would be the place field +otherwise it just collapse all this this + + align:start position:0% +otherwise it just collapse all this this + + + align:start position:0% +otherwise it just collapse all this this +is the spiking now as a function of + + align:start position:0% +is the spiking now as a function of + + + align:start position:0% +is the spiking now as a function of +position and phase if I just look + + align:start position:0% +position and phase if I just look + + + align:start position:0% +position and phase if I just look +expecting as a function of position + + align:start position:0% +expecting as a function of position + + + align:start position:0% +expecting as a function of position +that's just the density of firing what I + + align:start position:0% +that's just the density of firing what I + + + align:start position:0% +that's just the density of firing what I +would get is a place field not many + + align:start position:0% +would get is a place field not many + + + align:start position:0% +would get is a place field not many +spikes here is the animal as the animal + + align:start position:0% +spikes here is the animal as the animal + + + align:start position:0% +spikes here is the animal as the animal +enters the field lots of spikes here as + + align:start position:0% +enters the field lots of spikes here as + + + align:start position:0% +enters the field lots of spikes here as +you get into this would be the classic + + align:start position:0% +you get into this would be the classic + + + align:start position:0% +you get into this would be the classic +spatial receptive field but now if I + + align:start position:0% +spatial receptive field but now if I + + + align:start position:0% +spatial receptive field but now if I +introduce phase as well now you say oh + + align:start position:0% +introduce phase as well now you say oh + + + align:start position:0% +introduce phase as well now you say oh +wait there's a systematic relationship + + align:start position:0% +wait there's a systematic relationship + + + align:start position:0% +wait there's a systematic relationship +as well between phase and location in + + align:start position:0% +as well between phase and location in + + + align:start position:0% +as well between phase and location in +fact phase is a better predictor of + + align:start position:0% +fact phase is a better predictor of + + + align:start position:0% +fact phase is a better predictor of +relative location than firing rate I + + align:start position:0% +relative location than firing rate I + + + align:start position:0% +relative location than firing rate I +asked when did the spike occur if they + + align:start position:0% +asked when did the spike occur if they + + + align:start position:0% +asked when did the spike occur if they +occurred here late in phase then I know + + align:start position:0% +occurred here late in phase then I know + + + align:start position:0% +occurred here late in phase then I know +the animal is just entering the field + + align:start position:0% +the animal is just entering the field + + + align:start position:0% +the animal is just entering the field +that occurs early in phase I know it's + + align:start position:0% +that occurs early in phase I know it's + + + align:start position:0% +that occurs early in phase I know it's +at the end of its field and that's + + align:start position:0% +at the end of its field and that's + + + align:start position:0% +at the end of its field and that's +interesting and this is a simple model + + align:start position:0% +interesting and this is a simple model + + + align:start position:0% +interesting and this is a simple model +that says well an easy way of explaining + + align:start position:0% +that says well an easy way of explaining + + + align:start position:0% +that says well an easy way of explaining +that is if you just have this + + align:start position:0% +that is if you just have this + + + align:start position:0% +that is if you just have this +excitability model and this was one of + + align:start position:0% +excitability model and this was one of + + + align:start position:0% +excitability model and this was one of +the questions that I guess you asked + + align:start position:0% +the questions that I guess you asked + + + align:start position:0% +the questions that I guess you asked +about the sweeping inhibition so if we + + align:start position:0% +about the sweeping inhibition so if we + + + align:start position:0% +about the sweeping inhibition so if we +just imagine that you have an input + + align:start position:0% +just imagine that you have an input + + + align:start position:0% +just imagine that you have an input +excitatory input shown in blue and then + + align:start position:0% +excitatory input shown in blue and then + + + align:start position:0% +excitatory input shown in blue and then +inhibitory input shown in red where the + + align:start position:0% +inhibitory input shown in red where the + + + align:start position:0% +inhibitory input shown in red where the +inhibition is oscillating and you you + + align:start position:0% +inhibition is oscillating and you you + + + align:start position:0% +inhibition is oscillating and you you +apply a very simple biophysical model + + align:start position:0% +apply a very simple biophysical model + + + align:start position:0% +apply a very simple biophysical model +that says a spike action potential is + + align:start position:0% +that says a spike action potential is + + + align:start position:0% +that says a spike action potential is +going to occur when excitation and blue + + align:start position:0% +going to occur when excitation and blue + + + align:start position:0% +going to occur when excitation and blue +exceeds inhibition and read more + + align:start position:0% +exceeds inhibition and read more + + + align:start position:0% +exceeds inhibition and read more +excitation and emission to get a spike + + align:start position:0% +excitation and emission to get a spike + + + align:start position:0% +excitation and emission to get a spike +so here as in this oscillation anywhere + + align:start position:0% +so here as in this oscillation anywhere + + + align:start position:0% +so here as in this oscillation anywhere +the red trace is higher than the blue + + align:start position:0% +the red trace is higher than the blue + + + align:start position:0% +the red trace is higher than the blue +trace no spiking so in this case when + + align:start position:0% +trace no spiking so in this case when + + + align:start position:0% +trace no spiking so in this case when +excitation is low you have to wait until + + align:start position:0% +excitation is low you have to wait until + + + align:start position:0% +excitation is low you have to wait until +inhibition drops all the way to here to + + align:start position:0% +inhibition drops all the way to here to + + + align:start position:0% +inhibition drops all the way to here to +get a spike this is late phase so we get + + align:start position:0% +get a spike this is late phase so we get + + + align:start position:0% +get a spike this is late phase so we get +citation means you have to wait until + + align:start position:0% +citation means you have to wait until + + + align:start position:0% +citation means you have to wait until +inhibition is low so this is a sweeping + + align:start position:0% +inhibition is low so this is a sweeping + + + align:start position:0% +inhibition is low so this is a sweeping +inhibition you have to wait till it's + + align:start position:0% +inhibition you have to wait till it's + + + align:start position:0% +inhibition you have to wait till it's +low when excitation is strong I don't + + align:start position:0% +low when excitation is strong I don't + + + align:start position:0% +low when excitation is strong I don't +have to wait so long + + align:start position:0% +have to wait so long + + + align:start position:0% +have to wait so long +you can fire earlier so the principle + + align:start position:0% +you can fire earlier so the principle + + + align:start position:0% +you can fire earlier so the principle +here is that there's a relationship + + align:start position:0% +here is that there's a relationship + + + align:start position:0% +here is that there's a relationship +between magnitude and latency stronger + + align:start position:0% +between magnitude and latency stronger + + + align:start position:0% +between magnitude and latency stronger +means earlier that's the biophysical + + align:start position:0% +means earlier that's the biophysical + + + align:start position:0% +means earlier that's the biophysical +principle very simple stronger earlier + + align:start position:0% +principle very simple stronger earlier + + + align:start position:0% +principle very simple stronger earlier +weaker later that will give you this + + align:start position:0% +weaker later that will give you this + + + align:start position:0% +weaker later that will give you this +phase procession property phase + + align:start position:0% +phase procession property phase + + + align:start position:0% +phase procession property phase +procession you might think of as this + + align:start position:0% +procession you might think of as this + + + align:start position:0% +procession you might think of as this +biophysical curiosity but when you think + + align:start position:0% +biophysical curiosity but when you think + + + align:start position:0% +biophysical curiosity but when you think +about how that would apply when you have + + align:start position:0% +about how that would apply when you have + + + align:start position:0% +about how that would apply when you have +more than one place cell in fact I have + + align:start position:0% +more than one place cell in fact I have + + + align:start position:0% +more than one place cell in fact I have +two to play cells here one in blue one + + align:start position:0% +two to play cells here one in blue one + + + align:start position:0% +two to play cells here one in blue one +here in purple where play cell one is to + + align:start position:0% +here in purple where play cell one is to + + + align:start position:0% +here in purple where play cell one is to +the left of play cell two + + align:start position:0% +the left of play cell two + + + align:start position:0% +the left of play cell two +so as the animals going through here + + align:start position:0% +so as the animals going through here + + + align:start position:0% +so as the animals going through here +first the blue cell will fire and then + + align:start position:0% +first the blue cell will fire and then + + + align:start position:0% +first the blue cell will fire and then +the purple cell will fire and if you + + align:start position:0% +the purple cell will fire and if you + + + align:start position:0% +the purple cell will fire and if you +look at the excitement sort of the + + align:start position:0% +look at the excitement sort of the + + + align:start position:0% +look at the excitement sort of the +excitatory Drive shown here is a ramp in + + align:start position:0% +excitatory Drive shown here is a ramp in + + + align:start position:0% +excitatory Drive shown here is a ramp in +blue ramp and purple and now you ask + + align:start position:0% +blue ramp and purple and now you ask + + + align:start position:0% +blue ramp and purple and now you ask +when is the blue cell going to fire and + + align:start position:0% +when is the blue cell going to fire and + + + align:start position:0% +when is the blue cell going to fire and +the purple slug on a fire during each + + align:start position:0% +the purple slug on a fire during each + + + align:start position:0% +the purple slug on a fire during each +one of these oscillatory cycles and the + + align:start position:0% +one of these oscillatory cycles and the + + + align:start position:0% +one of these oscillatory cycles and the +answer will be well because the blue the + + align:start position:0% +answer will be well because the blue the + + + align:start position:0% +answer will be well because the blue the +excitatory drives the blue cell is + + align:start position:0% +excitatory drives the blue cell is + + + align:start position:0% +excitatory drives the blue cell is +higher than the purple cell blue is + + align:start position:0% +higher than the purple cell blue is + + + align:start position:0% +higher than the purple cell blue is +always going to fire before purple in + + align:start position:0% +always going to fire before purple in + + + align:start position:0% +always going to fire before purple in +fact in each and every cycle it will be + + align:start position:0% +fact in each and every cycle it will be + + + align:start position:0% +fact in each and every cycle it will be +blue purple blue purple blue purple so + + align:start position:0% +blue purple blue purple blue purple so + + + align:start position:0% +blue purple blue purple blue purple so +this principle of phase procession or + + align:start position:0% +this principle of phase procession or + + + align:start position:0% +this principle of phase procession or +phase coding for single cells actually + + align:start position:0% +phase coding for single cells actually + + + align:start position:0% +phase coding for single cells actually +gives you sequential encoding across a + + align:start position:0% +gives you sequential encoding across a + + + align:start position:0% +gives you sequential encoding across a +population that you will actually on + + align:start position:0% +population that you will actually on + + + align:start position:0% +population that you will actually on +each and every cycle have a sequence the + + align:start position:0% +each and every cycle have a sequence the + + + align:start position:0% +each and every cycle have a sequence the +code in the hippocampus is not a + + align:start position:0% +code in the hippocampus is not a + + + align:start position:0% +code in the hippocampus is not a +location it's actually a sequence a + + align:start position:0% +location it's actually a sequence a + + + align:start position:0% +location it's actually a sequence a +trajectory and this is just raw data but + + align:start position:0% +trajectory and this is just raw data but + + + align:start position:0% +trajectory and this is just raw data but +I'm gonna quickly go this is just the + + align:start position:0% +I'm gonna quickly go this is just the + + + align:start position:0% +I'm gonna quickly go this is just the +spiking looks like and you can see if + + align:start position:0% +spiking looks like and you can see if + + + align:start position:0% +spiking looks like and you can see if +you look at you see these kind of spike + + align:start position:0% +you look at you see these kind of spike + + + align:start position:0% +you look at you see these kind of spike +sequences + + align:start position:0% +sequences + + + align:start position:0% +sequences +but the property is more clearly + + align:start position:0% +but the property is more clearly + + + align:start position:0% +but the property is more clearly +demonstrated when I do this decoding so + + align:start position:0% +demonstrated when I do this decoding so + + + align:start position:0% +demonstrated when I do this decoding so +what's your what I'm showing you here + + align:start position:0% +what's your what I'm showing you here + + + align:start position:0% +what's your what I'm showing you here +this is again raw data but now instead + + align:start position:0% +this is again raw data but now instead + + + align:start position:0% +this is again raw data but now instead +of showing you the spiking I'm showing + + align:start position:0% +of showing you the spiking I'm showing + + + align:start position:0% +of showing you the spiking I'm showing +you that the result of doing this + + align:start position:0% +you that the result of doing this + + + align:start position:0% +you that the result of doing this +decoding this Bayesian decoding where + + align:start position:0% +decoding this Bayesian decoding where + + + align:start position:0% +decoding this Bayesian decoding where +there's a probability estimate that + + align:start position:0% +there's a probability estimate that + + + align:start position:0% +there's a probability estimate that +given spiking activity in each one of us + + align:start position:0% +given spiking activity in each one of us + + + align:start position:0% +given spiking activity in each one of us +set of successive 20 millisecond windows + + align:start position:0% +set of successive 20 millisecond windows + + + align:start position:0% +set of successive 20 millisecond windows +so I'm walking along now at a fire at a + + align:start position:0% +so I'm walking along now at a fire at a + + + align:start position:0% +so I'm walking along now at a fire at a +finer temporal resolution every 20 + + align:start position:0% +finer temporal resolution every 20 + + + align:start position:0% +finer temporal resolution every 20 +milliseconds I'm doing the same decoding + + align:start position:0% +milliseconds I'm doing the same decoding + + + align:start position:0% +milliseconds I'm doing the same decoding +probability is indicated in greyscale so + + align:start position:0% +probability is indicated in greyscale so + + + align:start position:0% +probability is indicated in greyscale so +you can see here the dark areas this is + + align:start position:0% +you can see here the dark areas this is + + + align:start position:0% +you can see here the dark areas this is +like high probability that this pattern + + align:start position:0% +like high probability that this pattern + + + align:start position:0% +like high probability that this pattern +the animal would have been in this + + align:start position:0% +the animal would have been in this + + + align:start position:0% +the animal would have been in this +location or to get this pattern of + + align:start position:0% +location or to get this pattern of + + + align:start position:0% +location or to get this pattern of +activity in this 20 millisecond bin and + + align:start position:0% +activity in this 20 millisecond bin and + + + align:start position:0% +activity in this 20 millisecond bin and +what you can see here is that the + + align:start position:0% +what you can see here is that the + + + align:start position:0% +what you can see here is that the +probability these Bayesian decoded of + + align:start position:0% +probability these Bayesian decoded of + + + align:start position:0% +probability these Bayesian decoded of +probabilities form short sequences every + + align:start position:0% +probabilities form short sequences every + + + align:start position:0% +probabilities form short sequences every +single theta cycle what we've heard is + + align:start position:0% +single theta cycle what we've heard is + + + align:start position:0% +single theta cycle what we've heard is +theta sequences and the theta sequences + + align:start position:0% +theta sequences and the theta sequences + + + align:start position:0% +theta sequences and the theta sequences +actually move from just behind the + + align:start position:0% +actually move from just behind the + + + align:start position:0% +actually move from just behind the +animal dotted line is where the animal + + align:start position:0% +animal dotted line is where the animal + + + align:start position:0% +animal dotted line is where the animal +actually is estimate goes and just + + align:start position:0% +actually is estimate goes and just + + + align:start position:0% +actually is estimate goes and just +behind the animal just in front of the + + align:start position:0% +behind the animal just in front of the + + + align:start position:0% +behind the animal just in front of the +animal so 10 times a second hippocampus + + align:start position:0% +animal so 10 times a second hippocampus + + + align:start position:0% +animal so 10 times a second hippocampus +is actually expressing a representation + + align:start position:0% +is actually expressing a representation + + + align:start position:0% +is actually expressing a representation +of spatial sequence that goes from + + align:start position:0% +of spatial sequence that goes from + + + align:start position:0% +of spatial sequence that goes from +behind to in front the animal you can + + align:start position:0% +behind to in front the animal you can + + + align:start position:0% +behind to in front the animal you can +think of behind in the front as also + + align:start position:0% +think of behind in the front as also + + + align:start position:0% +think of behind in the front as also +reflecting like recent past in near + + align:start position:0% +reflecting like recent past in near + + + align:start position:0% +reflecting like recent past in near +future so there is this relative + + align:start position:0% +future so there is this relative + + + align:start position:0% +future so there is this relative +predictive differentiation of response + + align:start position:0% +predictive differentiation of response + + + align:start position:0% +predictive differentiation of response +as a function of oscillatory phase so if + + align:start position:0% +as a function of oscillatory phase so if + + + align:start position:0% +as a function of oscillatory phase so if +I want to look at see where did I just + + align:start position:0% +I want to look at see where did I just + + + align:start position:0% +I want to look at see where did I just +come from I just have to look at + + align:start position:0% +come from I just have to look at + + + align:start position:0% +come from I just have to look at +activity here at this slightly earlier + + align:start position:0% +activity here at this slightly earlier + + + align:start position:0% +activity here at this slightly earlier +phase if I want to ask the question gee + + align:start position:0% +phase if I want to ask the question gee + + + align:start position:0% +phase if I want to ask the question gee +where am I likely to go to I simply have + + align:start position:0% +where am I likely to go to I simply have + + + align:start position:0% +where am I likely to go to I simply have +to shift the phase the channel that I + + align:start position:0% +to shift the phase the channel that I + + + align:start position:0% +to shift the phase the channel that I +look at here and I can see where the + + align:start position:0% +look at here and I can see where the + + + align:start position:0% +look at here and I can see where the +likely future location is so you can + + align:start position:0% +likely future location is so you can + + + align:start position:0% +likely future location is so you can +think that there is actually a code not + + align:start position:0% +think that there is actually a code not + + + align:start position:0% +think that there is actually a code not +just a location but of the relative + + align:start position:0% +just a location but of the relative + + + align:start position:0% +just a location but of the relative +causal relationship between locations + + align:start position:0% +causal relationship between locations + + + align:start position:0% +causal relationship between locations +mapped into phase and we'll see that we + + align:start position:0% +mapped into phase and we'll see that we + + + align:start position:0% +mapped into phase and we'll see that we +can experimentally test this idea that + + align:start position:0% +can experimentally test this idea that + + + align:start position:0% +can experimentally test this idea that +that's that's just not a you know like + + align:start position:0% +that's that's just not a you know like + + + align:start position:0% +that's that's just not a you know like +an artifact of our decoding but the + + align:start position:0% +an artifact of our decoding but the + + + align:start position:0% +an artifact of our decoding but the +animals are actually using information + + align:start position:0% +animals are actually using information + + + align:start position:0% +animals are actually using information +at these different phases + + align:start position:0% +at these different phases + + + align:start position:0% +at these different phases +to drive spatial navigation in + + align:start position:0% +to drive spatial navigation in + + + align:start position:0% +to drive spatial navigation in +particular ways by using some of the + + align:start position:0% +particular ways by using some of the + + + align:start position:0% +particular ways by using some of the +tools for manipulating activity in a + + align:start position:0% +tools for manipulating activity in a + + + align:start position:0% +tools for manipulating activity in a +closed this so-called closed loop option + + align:start position:0% +closed this so-called closed loop option + + + align:start position:0% +closed this so-called closed loop option +X so we see we can manipulate activity + + align:start position:0% +X so we see we can manipulate activity + + + align:start position:0% +X so we see we can manipulate activity +specifically manipulate activity became + + align:start position:0% +specifically manipulate activity became + + + align:start position:0% +specifically manipulate activity became +plac tivity different phases and show + + align:start position:0% +plac tivity different phases and show + + + align:start position:0% +plac tivity different phases and show +these different phases actually carry + + align:start position:0% +these different phases actually carry + + + align:start position:0% +these different phases actually carry +different functional consequences so + + align:start position:0% +different functional consequences so + + + align:start position:0% +different functional consequences so +we've got these sequences so i've got + + align:start position:0% +we've got these sequences so i've got + + + align:start position:0% +we've got these sequences so i've got +these sequences captured during these + + align:start position:0% +these sequences captured during these + + + align:start position:0% +these sequences captured during these +oscillations are these things actually + + align:start position:0% +oscillations are these things actually + + + align:start position:0% +oscillations are these things actually +meaningful or some of the indications + + align:start position:0% +meaningful or some of the indications + + + align:start position:0% +meaningful or some of the indications +that these that the a the oscillations + + align:start position:0% +that these that the a the oscillations + + + align:start position:0% +that these that the a the oscillations +and the sequences are meaningful first + + align:start position:0% +and the sequences are meaningful first + + + align:start position:0% +and the sequences are meaningful first +come from the observation that as i as i + + align:start position:0% +come from the observation that as i as i + + + align:start position:0% +come from the observation that as i as i +mentioned actually successful using + + align:start position:0% +mentioned actually successful using + + + align:start position:0% +mentioned actually successful using +memory information that the campus + + align:start position:0% +memory information that the campus + + + align:start position:0% +memory information that the campus +requires that you actually communicate + + align:start position:0% +requires that you actually communicate + + + align:start position:0% +requires that you actually communicate +this to executive structures that can + + align:start position:0% +this to executive structures that can + + + align:start position:0% +this to executive structures that can +guide behavior make decisions that would + + align:start position:0% +guide behavior make decisions that would + + + align:start position:0% +guide behavior make decisions that would +include the prefrontal cortex portions + + align:start position:0% +include the prefrontal cortex portions + + + align:start position:0% +include the prefrontal cortex portions +of prefrontal cortex which form a part + + align:start position:0% +of prefrontal cortex which form a part + + + align:start position:0% +of prefrontal cortex which form a part +of this limbic circuit and for those the + + align:start position:0% +of this limbic circuit and for those the + + + align:start position:0% +of this limbic circuit and for those the +limbic prefrontal cortex which have + + align:start position:0% +limbic prefrontal cortex which have + + + align:start position:0% +limbic prefrontal cortex which have +direct connections from the hippocampus + + align:start position:0% +direct connections from the hippocampus + + + align:start position:0% +direct connections from the hippocampus +these structures are in the hippocampus + + align:start position:0% +these structures are in the hippocampus + + + align:start position:0% +these structures are in the hippocampus +you have deficits and spatial learning + + align:start position:0% +you have deficits and spatial learning + + + align:start position:0% +you have deficits and spatial learning +memory prefrontal cortex you sort of + + align:start position:0% +memory prefrontal cortex you sort of + + + align:start position:0% +memory prefrontal cortex you sort of +think of this as as you know sort of + + align:start position:0% +think of this as as you know sort of + + + align:start position:0% +think of this as as you know sort of +deficits and in working memory and + + align:start position:0% +deficits and in working memory and + + + align:start position:0% +deficits and in working memory and +retrieval executive control + + align:start position:0% +retrieval executive control + + + align:start position:0% +retrieval executive control +decision-making but but you can think of + + align:start position:0% +decision-making but but you can think of + + + align:start position:0% +decision-making but but you can think of +these two things is working together + + align:start position:0% +these two things is working together + + + align:start position:0% +these two things is working together +again hippocampus providing information + + align:start position:0% +again hippocampus providing information + + + align:start position:0% +again hippocampus providing information +that the prefrontal cortex can use in + + align:start position:0% +that the prefrontal cortex can use in + + + align:start position:0% +that the prefrontal cortex can use in +order to direct behavior and + + align:start position:0% +order to direct behavior and + + + align:start position:0% +order to direct behavior and +decision-making and you damage either + + align:start position:0% +decision-making and you damage either + + + align:start position:0% +decision-making and you damage either +one of these things animals rats can't + + align:start position:0% +one of these things animals rats can't + + + align:start position:0% +one of these things animals rats can't +find their way around the space you're + + align:start position:0% +find their way around the space you're + + + align:start position:0% +find their way around the space you're +damaged you either one of these in + + align:start position:0% +damaged you either one of these in + + + align:start position:0% +damaged you either one of these in +humans you're gonna get you're gonna get + + align:start position:0% +humans you're gonna get you're gonna get + + + align:start position:0% +humans you're gonna get you're gonna get +memory deficits and you know dementia is + + align:start position:0% +memory deficits and you know dementia is + + + align:start position:0% +memory deficits and you know dementia is +where you think of dementia as being you + + align:start position:0% +where you think of dementia as being you + + + align:start position:0% +where you think of dementia as being you +know problems of cognition and memory + + align:start position:0% +know problems of cognition and memory + + + align:start position:0% +know problems of cognition and memory +you can get them temporal lobe dementia + + align:start position:0% +you can get them temporal lobe dementia + + + align:start position:0% +you can get them temporal lobe dementia +as frontal lobe dementia they have you + + align:start position:0% +as frontal lobe dementia they have you + + + align:start position:0% +as frontal lobe dementia they have you +know they have they they're they're + + align:start position:0% +know they have they they're they're + + + align:start position:0% +know they have they they're they're +really very closely related and so we + + align:start position:0% +really very closely related and so we + + + align:start position:0% +really very closely related and so we +can look at a simple task this is a + + align:start position:0% +can look at a simple task this is a + + + align:start position:0% +can look at a simple task this is a +simple task testing a so called working + + align:start position:0% +simple task testing a so called working + + + align:start position:0% +simple task testing a so called working +memory just remember what did you do + + align:start position:0% +memory just remember what did you do + + + align:start position:0% +memory just remember what did you do +last in this task it's just a simple + + align:start position:0% +last in this task it's just a simple + + + align:start position:0% +last in this task it's just a simple +alternation where you turn left first + + align:start position:0% +alternation where you turn left first + + + align:start position:0% +alternation where you turn left first +time you turn left + + align:start position:0% +time you turn left + + + align:start position:0% +time you turn left +next time you go right Etha logically + + align:start position:0% +next time you go right Etha logically + + + align:start position:0% +next time you go right Etha logically +it's like look I just got food over here + + align:start position:0% +it's like look I just got food over here + + + align:start position:0% +it's like look I just got food over here +why don't I check out the other place + + align:start position:0% +why don't I check out the other place + + + align:start position:0% +why don't I check out the other place +right I'll check out places where I + + align:start position:0% +right I'll check out places where I + + + align:start position:0% +right I'll check out places where I +didn't get food this is this it's the + + align:start position:0% +didn't get food this is this it's the + + + align:start position:0% +didn't get food this is this it's the +so-called wind shift strategy I got + + align:start position:0% +so-called wind shift strategy I got + + + align:start position:0% +so-called wind shift strategy I got +something here this time and go + + align:start position:0% +something here this time and go + + + align:start position:0% +something here this time and go +someplace else as opposed to like a + + align:start position:0% +someplace else as opposed to like a + + + align:start position:0% +someplace else as opposed to like a +reference memory strategy would be where + + align:start position:0% +reference memory strategy would be where + + + align:start position:0% +reference memory strategy would be where +they for there's a winds day that's + + align:start position:0% +they for there's a winds day that's + + + align:start position:0% +they for there's a winds day that's +really a good spot you know home I love + + align:start position:0% +really a good spot you know home I love + + + align:start position:0% +really a good spot you know home I love +going home because you know I've got my + + align:start position:0% +going home because you know I've got my + + + align:start position:0% +going home because you know I've got my +MIT ve got my microwave I'm gonna stick + + align:start position:0% +MIT ve got my microwave I'm gonna stick + + + align:start position:0% +MIT ve got my microwave I'm gonna stick +with that place Wednesdays you keep + + align:start position:0% +with that place Wednesdays you keep + + + align:start position:0% +with that place Wednesdays you keep +going back to the place that you know + + align:start position:0% +going back to the place that you know + + + align:start position:0% +going back to the place that you know +that rewards you and so you can think of + + align:start position:0% +that rewards you and so you can think of + + + align:start position:0% +that rewards you and so you can think of +both again both these things have you + + align:start position:0% +both again both these things have you + + + align:start position:0% +both again both these things have you +Falacci value home is a good place + + align:start position:0% +Falacci value home is a good place + + + align:start position:0% +Falacci value home is a good place +that's reference place if you're + + align:start position:0% +that's reference place if you're + + + align:start position:0% +that's reference place if you're +foraging wind shift don't go back to the + + align:start position:0% +foraging wind shift don't go back to the + + + align:start position:0% +foraging wind shift don't go back to the +place I just glued it right and so if + + align:start position:0% +place I just glued it right and so if + + + align:start position:0% +place I just glued it right and so if +you again these two these two structures + + align:start position:0% + + + + align:start position:0% + +classically you think of in the + + align:start position:0% +classically you think of in the + + + align:start position:0% +classically you think of in the +prefrontal cortex we think of working + + align:start position:0% +prefrontal cortex we think of working + + + align:start position:0% +prefrontal cortex we think of working +memory cells this is the short-term the + + align:start position:0% +memory cells this is the short-term the + + + align:start position:0% +memory cells this is the short-term the +idea of a short-term memory so + + align:start position:0% +idea of a short-term memory so + + + align:start position:0% +idea of a short-term memory so +prefrontal cortex tippet has been + + align:start position:0% +prefrontal cortex tippet has been + + + align:start position:0% +prefrontal cortex tippet has been +thought of as sub serving working memory + + align:start position:0% +thought of as sub serving working memory + + + align:start position:0% +thought of as sub serving working memory +where working memory is about holding + + align:start position:0% +where working memory is about holding + + + align:start position:0% +where working memory is about holding +information over short delays it's a + + align:start position:0% +information over short delays it's a + + + align:start position:0% +information over short delays it's a +it's a it's kind of a an overlap in + + align:start position:0% +it's a it's kind of a an overlap in + + + align:start position:0% +it's a it's kind of a an overlap in +terminology we're working memory in the + + align:start position:0% +terminology we're working memory in the + + + align:start position:0% +terminology we're working memory in the +prefrontal cortex really thinking about + + align:start position:0% +prefrontal cortex really thinking about + + + align:start position:0% +prefrontal cortex really thinking about +time working memory and hippocampus it's + + align:start position:0% +time working memory and hippocampus it's + + + align:start position:0% +time working memory and hippocampus it's +really thinking about kind of the you + + align:start position:0% +really thinking about kind of the you + + + align:start position:0% +really thinking about kind of the you +know the context in which it's used + + align:start position:0% +know the context in which it's used + + + align:start position:0% +know the context in which it's used +relative such and specific information + + align:start position:0% +relative such and specific information + + + align:start position:0% +relative such and specific information +trial specific information so I'm not + + align:start position:0% +trial specific information so I'm not + + + align:start position:0% +trial specific information so I'm not +gonna go through the details just you + + align:start position:0% +gonna go through the details just you + + + align:start position:0% +gonna go through the details just you +have these two systems and one + + align:start position:0% +have these two systems and one + + + align:start position:0% +have these two systems and one +interesting property in the if you look + + align:start position:0% +interesting property in the if you look + + + align:start position:0% +interesting property in the if you look +at these two systems simultaneously what + + align:start position:0% +at these two systems simultaneously what + + + align:start position:0% +at these two systems simultaneously what +you find is that the same idea about + + align:start position:0% +you find is that the same idea about + + + align:start position:0% +you find is that the same idea about +oscillatory phase governing the firing + + align:start position:0% +oscillatory phase governing the firing + + + align:start position:0% +oscillatory phase governing the firing +of cells in the hippocampus also applies + + align:start position:0% +of cells in the hippocampus also applies + + + align:start position:0% +of cells in the hippocampus also applies +in the prefrontal cortex that has cells + + align:start position:0% +in the prefrontal cortex that has cells + + + align:start position:0% +in the prefrontal cortex that has cells +in the prefrontal cortex like to fire at + + align:start position:0% +in the prefrontal cortex like to fire at + + + align:start position:0% +in the prefrontal cortex like to fire at +certain phase of the hippocampal theta + + align:start position:0% +certain phase of the hippocampal theta + + + align:start position:0% +certain phase of the hippocampal theta +rhythm they care about they're listening + + align:start position:0% +rhythm they care about they're listening + + + align:start position:0% +rhythm they care about they're listening +to this rhythm in the hippocampus and so + + align:start position:0% +to this rhythm in the hippocampus and so + + + align:start position:0% +to this rhythm in the hippocampus and so +we can look at a task this is basically + + align:start position:0% +we can look at a task this is basically + + + align:start position:0% +we can look at a task this is basically +the same kind of task only now there's a + + align:start position:0% +the same kind of task only now there's a + + + align:start position:0% +the same kind of task only now there's a +back-to-back teammates there's gonna be + + align:start position:0% +back-to-back teammates there's gonna be + + + align:start position:0% +back-to-back teammates there's gonna be +two tea mazes and we're just gonna do a + + align:start position:0% +two tea mazes and we're just gonna do a + + + align:start position:0% +two tea mazes and we're just gonna do a +simple variation on that well that + + align:start position:0% +simple variation on that well that + + + align:start position:0% +simple variation on that well that +working memory task + + align:start position:0% +working memory task + + + align:start position:0% +working memory task +in which animals gonna start from one of + + align:start position:0% +in which animals gonna start from one of + + + align:start position:0% +in which animals gonna start from one of +these two arms can walk down this arm + + align:start position:0% +these two arms can walk down this arm + + + align:start position:0% +these two arms can walk down this arm +and then it has to go to the arm that's + + align:start position:0% +and then it has to go to the arm that's + + + align:start position:0% +and then it has to go to the arm that's +on the same side that it started from so + + align:start position:0% +on the same side that it started from so + + + align:start position:0% +on the same side that it started from so +it has to remember where did I start + + align:start position:0% +it has to remember where did I start + + + align:start position:0% +it has to remember where did I start +from oh that's the side I have to go to + + align:start position:0% +from oh that's the side I have to go to + + + align:start position:0% +from oh that's the side I have to go to +then it's going to turn around it's + + align:start position:0% +then it's going to turn around it's + + + align:start position:0% +then it's going to turn around it's +gonna come back run down here and then + + align:start position:0% +gonna come back run down here and then + + + align:start position:0% +gonna come back run down here and then +we're gonna force it into one of these + + align:start position:0% +we're gonna force it into one of these + + + align:start position:0% +we're gonna force it into one of these +arms so there's two back to back tea + + align:start position:0% +arms so there's two back to back tea + + + align:start position:0% +arms so there's two back to back tea +mazes in this direction the animal + + align:start position:0% +mazes in this direction the animal + + + align:start position:0% +mazes in this direction the animal +chooses in this direction we choose in + + align:start position:0% +chooses in this direction we choose in + + + align:start position:0% +chooses in this direction we choose in +this direction there's a working memory + + align:start position:0% +this direction there's a working memory + + + align:start position:0% +this direction there's a working memory +demand has to remember where it came + + align:start position:0% +demand has to remember where it came + + + align:start position:0% +demand has to remember where it came +from in this direction doesn't have to + + align:start position:0% +from in this direction doesn't have to + + + align:start position:0% +from in this direction doesn't have to +remember anything doesn't make any + + align:start position:0% +remember anything doesn't make any + + + align:start position:0% +remember anything doesn't make any +difference + + align:start position:0% +difference + + + align:start position:0% +difference +so behaviorally it's symmetric button + + align:start position:0% +so behaviorally it's symmetric button + + + align:start position:0% +so behaviorally it's symmetric button +cognitively here there's a working + + align:start position:0% +cognitively here there's a working + + + align:start position:0% +cognitively here there's a working +memory demand here it is not and then + + align:start position:0% +memory demand here it is not and then + + + align:start position:0% +memory demand here it is not and then +we're gonna look at all these things + + align:start position:0% +we're gonna look at all these things + + + align:start position:0% +we're gonna look at all these things +oscillation spiking and look the + + align:start position:0% +oscillation spiking and look the + + + align:start position:0% +oscillation spiking and look the +oscillations look at the peak time look + + align:start position:0% +oscillations look at the peak time look + + + align:start position:0% +oscillations look at the peak time look +at the firing with respect to that + + align:start position:0% +at the firing with respect to that + + + align:start position:0% +at the firing with respect to that +firing spiking as a function of this + + align:start position:0% +firing spiking as a function of this + + + align:start position:0% +firing spiking as a function of this +oscillation of both structures and the + + align:start position:0% +oscillation of both structures and the + + + align:start position:0% +oscillation of both structures and the +the bottom line is what you find is that + + align:start position:0% +the bottom line is what you find is that + + + align:start position:0% +the bottom line is what you find is that +this is a measure of this is a measure + + align:start position:0% +this is a measure of this is a measure + + + align:start position:0% +this is a measure of this is a measure +of relative phase locking and as how + + align:start position:0% +of relative phase locking and as how + + + align:start position:0% +of relative phase locking and as how +well how well do prefrontal cells + + align:start position:0% +well how well do prefrontal cells + + + align:start position:0% +well how well do prefrontal cells +actually lock to lock to this theta + + align:start position:0% +actually lock to lock to this theta + + + align:start position:0% +actually lock to lock to this theta +oscillation and what you find is that + + align:start position:0% +oscillation and what you find is that + + + align:start position:0% +oscillation and what you find is that +the degree to which they lock to theta + + align:start position:0% +the degree to which they lock to theta + + + align:start position:0% +the degree to which they lock to theta +rhythm is a function of whether or not + + align:start position:0% +rhythm is a function of whether or not + + + align:start position:0% +rhythm is a function of whether or not +the animal has to choose so the red ones + + align:start position:0% +the animal has to choose so the red ones + + + align:start position:0% +the animal has to choose so the red ones +are when the animals going down the arm + + align:start position:0% +are when the animals going down the arm + + + align:start position:0% +are when the animals going down the arm +and it's got to choose the gray one is + + align:start position:0% +and it's got to choose the gray one is + + + align:start position:0% +and it's got to choose the gray one is +when we when it doesn't have to choose + + align:start position:0% +when we when it doesn't have to choose + + + align:start position:0% +when we when it doesn't have to choose +when we choose then in addition the + + align:start position:0% +when we choose then in addition the + + + align:start position:0% +when we choose then in addition the +solid red is when the animal had to + + align:start position:0% +solid red is when the animal had to + + + align:start position:0% +solid red is when the animal had to +choose and it got it right and the + + align:start position:0% +choose and it got it right and the + + + align:start position:0% +choose and it got it right and the +stipler red is when and had to choose + + align:start position:0% +stipler red is when and had to choose + + + align:start position:0% +stipler red is when and had to choose +and it got it wrong so the degree to + + align:start position:0% +and it got it wrong so the degree to + + + align:start position:0% +and it got it wrong so the degree to +which the prefrontal cortex actually + + align:start position:0% +which the prefrontal cortex actually + + + align:start position:0% +which the prefrontal cortex actually +locks successfully locks to the + + align:start position:0% +locks successfully locks to the + + + align:start position:0% +locks successfully locks to the +hippocampal theta rhythm predicts + + align:start position:0% +hippocampal theta rhythm predicts + + + align:start position:0% +hippocampal theta rhythm predicts +whether the animal actually makes the + + align:start position:0% +whether the animal actually makes the + + + align:start position:0% +whether the animal actually makes the +correct choice or not so it says though + + align:start position:0% +correct choice or not so it says though + + + align:start position:0% +correct choice or not so it says though +this is a channel that is necessary for + + align:start position:0% +this is a channel that is necessary for + + + align:start position:0% +this is a channel that is necessary for +effectively communicating information + + align:start position:0% +effectively communicating information + + + align:start position:0% +effectively communicating information +between the two structures and + + align:start position:0% +between the two structures and + + + align:start position:0% +between the two structures and +that not only is it in the in the + + align:start position:0% +that not only is it in the in the + + + align:start position:0% +that not only is it in the in the +blocking of the spikes spikes in the + + align:start position:0% +blocking of the spikes spikes in the + + + align:start position:0% +blocking of the spikes spikes in the +prefrontal cortex the rhythm neighbor + + align:start position:0% +prefrontal cortex the rhythm neighbor + + + align:start position:0% +prefrontal cortex the rhythm neighbor +campus it also comes in the blocking of + + align:start position:0% +campus it also comes in the blocking of + + + align:start position:0% +campus it also comes in the blocking of +the rhythms themselves so you can think + + align:start position:0% +the rhythms themselves so you can think + + + align:start position:0% +the rhythms themselves so you can think +of there being this is the this is the + + align:start position:0% +of there being this is the this is the + + + align:start position:0% +of there being this is the this is the +theta rhythm that you can detecting the + + align:start position:0% +theta rhythm that you can detecting the + + + align:start position:0% +theta rhythm that you can detecting the +prefrontal cortex and the hippocampus + + align:start position:0% +prefrontal cortex and the hippocampus + + + align:start position:0% +prefrontal cortex and the hippocampus +and what you can see is there two + + align:start position:0% +and what you can see is there two + + + align:start position:0% +and what you can see is there two +conditions one you're the animal is + + align:start position:0% +conditions one you're the animal is + + + align:start position:0% +conditions one you're the animal is +actually choosing it's running down here + + align:start position:0% +actually choosing it's running down here + + + align:start position:0% +actually choosing it's running down here +as making a choice and in about the half + + align:start position:0% +as making a choice and in about the half + + + align:start position:0% +as making a choice and in about the half +second before the animal makes a choice + + align:start position:0% +second before the animal makes a choice + + + align:start position:0% +second before the animal makes a choice +you see these two rhythms actually lock + + align:start position:0% +you see these two rhythms actually lock + + + align:start position:0% +you see these two rhythms actually lock +they become coherent so transient + + align:start position:0% +they become coherent so transient + + + align:start position:0% +they become coherent so transient +coherence is predictive of correct + + align:start position:0% +coherence is predictive of correct + + + align:start position:0% +coherence is predictive of correct +choice behavior you know the thinking is + + align:start position:0% +choice behavior you know the thinking is + + + align:start position:0% +choice behavior you know the thinking is +that the rhythms themselves can be + + align:start position:0% +that the rhythms themselves can be + + + align:start position:0% +that the rhythms themselves can be +generating coordinated through the + + align:start position:0% +generating coordinated through the + + + align:start position:0% +generating coordinated through the +regulation of these local inhibitory + + align:start position:0% +regulation of these local inhibitory + + + align:start position:0% +regulation of these local inhibitory +circuits in fact there's been a lot of + + align:start position:0% +circuits in fact there's been a lot of + + + align:start position:0% +circuits in fact there's been a lot of +interest for instance in the + + align:start position:0% +interest for instance in the + + + align:start position:0% +interest for instance in the +relationship of local inhibitory control + + align:start position:0% +relationship of local inhibitory control + + + align:start position:0% +relationship of local inhibitory control +and neuropsychiatric disease and + + align:start position:0% +and neuropsychiatric disease and + + + align:start position:0% +and neuropsychiatric disease and +disorders so for instance disrupting + + align:start position:0% +disorders so for instance disrupting + + + align:start position:0% +disorders so for instance disrupting +local inhibitory rhythms in particular + + align:start position:0% +local inhibitory rhythms in particular + + + align:start position:0% +local inhibitory rhythms in particular +some like for instance the theta rhythms + + align:start position:0% +some like for instance the theta rhythms + + + align:start position:0% +some like for instance the theta rhythms +in prefrontal cortex can be associated + + align:start position:0% +in prefrontal cortex can be associated + + + align:start position:0% +in prefrontal cortex can be associated +with the sores like schizophrenia for + + align:start position:0% +with the sores like schizophrenia for + + + align:start position:0% +with the sores like schizophrenia for +instance so the inability to effectively + + align:start position:0% +instance so the inability to effectively + + + align:start position:0% +instance so the inability to effectively +impose these modes and then synchronize + + align:start position:0% +impose these modes and then synchronize + + + align:start position:0% +impose these modes and then synchronize +these modes can be seen as can can + + align:start position:0% +these modes can be seen as can can + + + align:start position:0% +these modes can be seen as can can +introduce disruptions in the ability to + + align:start position:0% +introduce disruptions in the ability to + + + align:start position:0% +introduce disruptions in the ability to +communicate or use memory cognitive + + align:start position:0% +communicate or use memory cognitive + + + align:start position:0% +communicate or use memory cognitive +disruption coming through disruption of + + align:start position:0% +disruption coming through disruption of + + + align:start position:0% +disruption coming through disruption of +these oscillations through disruption of + + align:start position:0% +these oscillations through disruption of + + + align:start position:0% +these oscillations through disruption of +inhibition in these local circuits now + + align:start position:0% +inhibition in these local circuits now + + + align:start position:0% +inhibition in these local circuits now +how you actually coordinate these two + + align:start position:0% +how you actually coordinate these two + + + align:start position:0% +how you actually coordinate these two +subjective you know study so we've been + + align:start position:0% +subjective you know study so we've been + + + align:start position:0% +subjective you know study so we've been +looking at the role of like midline + + align:start position:0% +looking at the role of like midline + + + align:start position:0% +looking at the role of like midline +thalamic nuclei and so the thalamus as + + align:start position:0% +thalamic nuclei and so the thalamus as + + + align:start position:0% +thalamic nuclei and so the thalamus as +being a you know set of structures that + + align:start position:0% +being a you know set of structures that + + + align:start position:0% +being a you know set of structures that +have widespread connectivity to all + + align:start position:0% +have widespread connectivity to all + + + align:start position:0% +have widespread connectivity to all +these cortical areas that they have much + + align:start position:0% +these cortical areas that they have much + + + align:start position:0% +these cortical areas that they have much +of their connectivity is inhibitory and + + align:start position:0% +of their connectivity is inhibitory and + + + align:start position:0% +of their connectivity is inhibitory and +so they have the ability to actually + + align:start position:0% +so they have the ability to actually + + + align:start position:0% +so they have the ability to actually +coordinate modulate and coordinate these + + align:start position:0% +coordinate modulate and coordinate these + + + align:start position:0% +coordinate modulate and coordinate these +oscillatory modes like we've even just + + align:start position:0% +oscillatory modes like we've even just + + + align:start position:0% +oscillatory modes like we've even just +recently published on individual cells + + align:start position:0% +recently published on individual cells + + + align:start position:0% +recently published on individual cells +so we've found in some of these midline + + align:start position:0% +so we've found in some of these midline + + + align:start position:0% +so we've found in some of these midline +thalamic nuclei that for instance will + + align:start position:0% +thalamic nuclei that for instance will + + + align:start position:0% +thalamic nuclei that for instance will +branch single cells or branch + + align:start position:0% +branch single cells or branch + + + align:start position:0% +branch single cells or branch +target cells in hippocampus and the + + align:start position:0% +target cells in hippocampus and the + + + align:start position:0% +target cells in hippocampus and the +prefrontal cortex so they would be + + align:start position:0% +prefrontal cortex so they would be + + + align:start position:0% +prefrontal cortex so they would be +ideally positioned to introduce to kind + + align:start position:0% +ideally positioned to introduce to kind + + + align:start position:0% +ideally positioned to introduce to kind +of select and impose this + + align:start position:0% +of select and impose this + + + align:start position:0% +of select and impose this +synchronization there and so that's + + align:start position:0% +synchronization there and so that's + + + align:start position:0% +synchronization there and so that's +that's the way we think about a lot of + + align:start position:0% +that's the way we think about a lot of + + + align:start position:0% +that's the way we think about a lot of +this dynamic connectivity being + + align:start position:0% +this dynamic connectivity being + + + align:start position:0% +this dynamic connectivity being +established presumably through some sort + + align:start position:0% +established presumably through some sort + + + align:start position:0% +established presumably through some sort +of thermic regulation and then you think + + align:start position:0% +of thermic regulation and then you think + + + align:start position:0% +of thermic regulation and then you think +about the thalamus is being regulated by + + align:start position:0% +about the thalamus is being regulated by + + + align:start position:0% +about the thalamus is being regulated by +there's the so called the thalamic + + align:start position:0% +there's the so called the thalamic + + + align:start position:0% +there's the so called the thalamic +reticular nucleus that that regulates + + align:start position:0% +reticular nucleus that that regulates + + + align:start position:0% +reticular nucleus that that regulates +the thalamus and it kind of sets up + + align:start position:0% +the thalamus and it kind of sets up + + + align:start position:0% +the thalamus and it kind of sets up +these modes there's also a lot of + + align:start position:0% +these modes there's also a lot of + + + align:start position:0% +these modes there's also a lot of +interest now in the Philemon particular + + align:start position:0% +interest now in the Philemon particular + + + align:start position:0% +interest now in the Philemon particular +nucleus in disease and disorders a lot + + align:start position:0% +nucleus in disease and disorders a lot + + + align:start position:0% +nucleus in disease and disorders a lot +of that you know sort of the genetic + + align:start position:0% +of that you know sort of the genetic + + + align:start position:0% +of that you know sort of the genetic +screening has identified targets in the + + align:start position:0% +screening has identified targets in the + + + align:start position:0% +screening has identified targets in the +Flemming particular nucleus so you kind + + align:start position:0% +Flemming particular nucleus so you kind + + + align:start position:0% +Flemming particular nucleus so you kind +of think about again it's like the it's + + align:start position:0% +of think about again it's like the it's + + + align:start position:0% +of think about again it's like the it's +like the oscillator and you're you know + + align:start position:0% +like the oscillator and you're you know + + + align:start position:0% +like the oscillator and you're you know +in your computer or your you know your + + align:start position:0% +in your computer or your you know your + + + align:start position:0% +in your computer or your you know your +radio that breaks down you can you can't + + align:start position:0% +radio that breaks down you can you can't + + + align:start position:0% +radio that breaks down you can you can't +the information could be there but you + + align:start position:0% +the information could be there but you + + + align:start position:0% +the information could be there but you +can't tune into it so it's this + + align:start position:0% +can't tune into it so it's this + + + align:start position:0% +can't tune into it so it's this +fundamental tune you got to have the + + align:start position:0% +fundamental tune you got to have the + + + align:start position:0% +fundamental tune you got to have the +modes and you got to be able to lock to + + align:start position:0% +modes and you got to be able to lock to + + + align:start position:0% +modes and you got to be able to lock to +these frequencies and then beyond that + + align:start position:0% +these frequencies and then beyond that + + + align:start position:0% +these frequencies and then beyond that +as we'll see it's not just the + + align:start position:0% +as we'll see it's not just the + + + align:start position:0% +as we'll see it's not just the +frequencies but it's also the precise + + align:start position:0% +frequencies but it's also the precise + + + align:start position:0% +frequencies but it's also the precise +phase within those those oscillatory + + align:start position:0% +phase within those those oscillatory + + + align:start position:0% +phase within those those oscillatory +modes that carry different information + + align:start position:0% +modes that carry different information + + + align:start position:0% +modes that carry different information +that way actually determined by taking + + align:start position:0% +that way actually determined by taking + + + align:start position:0% +that way actually determined by taking +advantage of these techniques + + align:start position:0% +advantage of these techniques + + + align:start position:0% +advantage of these techniques +optogenetic techniques for targeted + + align:start position:0% +optogenetic techniques for targeted + + + align:start position:0% +optogenetic techniques for targeted +manipulation so you infect the HIPAA + + align:start position:0% +manipulation so you infect the HIPAA + + + align:start position:0% +manipulation so you infect the HIPAA +can't inhibitory neurons in the + + align:start position:0% +can't inhibitory neurons in the + + + align:start position:0% +can't inhibitory neurons in the +hippocampus with this optogenetic up + + align:start position:0% +hippocampus with this optogenetic up + + + align:start position:0% +hippocampus with this optogenetic up +genetically encoded and controllable + + align:start position:0% +genetically encoded and controllable + + + align:start position:0% +genetically encoded and controllable +channel so that we can optically excite + + align:start position:0% +channel so that we can optically excite + + + align:start position:0% +channel so that we can optically excite +inhibitory cells so we infect this + + align:start position:0% +inhibitory cells so we infect this + + + align:start position:0% +inhibitory cells so we infect this +excitatory channel into inhibitory cells + + align:start position:0% +excitatory channel into inhibitory cells + + + align:start position:0% +excitatory channel into inhibitory cells +and then we can transiently giving very + + align:start position:0% +and then we can transiently giving very + + + align:start position:0% +and then we can transiently giving very +brief pulses of laser light we can + + align:start position:0% +brief pulses of laser light we can + + + align:start position:0% +brief pulses of laser light we can +activate Drive inhibitory cells and then + + align:start position:0% +activate Drive inhibitory cells and then + + + align:start position:0% +activate Drive inhibitory cells and then +because the local circuit those + + align:start position:0% +because the local circuit those + + + align:start position:0% +because the local circuit those +inhibitory cells will inhibit the + + align:start position:0% +inhibitory cells will inhibit the + + + align:start position:0% +inhibitory cells will inhibit the +excitatory cells so we have about 20-25 + + align:start position:0% +excitatory cells so we have about 20-25 + + + align:start position:0% +excitatory cells so we have about 20-25 +millisecond control and now we can lock + + align:start position:0% +millisecond control and now we can lock + + + align:start position:0% +millisecond control and now we can lock +or control inhibition based upon the + + align:start position:0% +or control inhibition based upon the + + + align:start position:0% +or control inhibition based upon the +phase of this oscillation so the eye + + align:start position:0% +phase of this oscillation so the eye + + + align:start position:0% +phase of this oscillation so the eye +is we're going to selectively disrupt or + + align:start position:0% +is we're going to selectively disrupt or + + + align:start position:0% +is we're going to selectively disrupt or +inactivate the hippocampus at different + + align:start position:0% +inactivate the hippocampus at different + + + align:start position:0% +inactivate the hippocampus at different +phases we're gonna ask do those phases + + align:start position:0% +phases we're gonna ask do those phases + + + align:start position:0% +phases we're gonna ask do those phases +that they differ in terms of their + + align:start position:0% +that they differ in terms of their + + + align:start position:0% +that they differ in terms of their +contribution to behavior and performance + + align:start position:0% +contribution to behavior and performance + + + align:start position:0% +contribution to behavior and performance +so here we're gonna lock inhibition + + align:start position:0% +so here we're gonna lock inhibition + + + align:start position:0% +so here we're gonna lock inhibition +either the peak of the trough of the + + align:start position:0% +either the peak of the trough of the + + + align:start position:0% +either the peak of the trough of the +state oscillation and so in this task + + align:start position:0% +state oscillation and so in this task + + + align:start position:0% +state oscillation and so in this task +and we're gonna do this manipulation + + align:start position:0% +and we're gonna do this manipulation + + + align:start position:0% +and we're gonna do this manipulation +that is selectively inhibit hippocampal + + align:start position:0% +that is selectively inhibit hippocampal + + + align:start position:0% +that is selectively inhibit hippocampal +output at either the peak of the trough + + align:start position:0% +output at either the peak of the trough + + + align:start position:0% +output at either the peak of the trough +the theta rhythm at to behavioral phases + + align:start position:0% +the theta rhythm at to behavioral phases + + + align:start position:0% +the theta rhythm at to behavioral phases +so in this task animals gonna start in + + align:start position:0% +so in this task animals gonna start in + + + align:start position:0% +so in this task animals gonna start in +one of these arms gonna run up and it's + + align:start position:0% +one of these arms gonna run up and it's + + + align:start position:0% +one of these arms gonna run up and it's +gonna choose so we're gonna think about + + align:start position:0% +gonna choose so we're gonna think about + + + align:start position:0% +gonna choose so we're gonna think about +the starting arms as we'll refer to this + + align:start position:0% +the starting arms as we'll refer to this + + + align:start position:0% +the starting arms as we'll refer to this +as the encoding phase is where you have + + align:start position:0% +as the encoding phase is where you have + + + align:start position:0% +as the encoding phase is where you have +to keep track of where you are and then + + align:start position:0% +to keep track of where you are and then + + + align:start position:0% +to keep track of where you are and then +here in the central arm will refer to + + align:start position:0% +here in the central arm will refer to + + + align:start position:0% +here in the central arm will refer to +this as the retrieval phase this is + + align:start position:0% +this as the retrieval phase this is + + + align:start position:0% +this as the retrieval phase this is +where you have to remember oh where did + + align:start position:0% +where you have to remember oh where did + + + align:start position:0% +where you have to remember oh where did +I come from and then use that to decide + + align:start position:0% +I come from and then use that to decide + + + align:start position:0% +I come from and then use that to decide +where you're going to go to and we found + + align:start position:0% +where you're going to go to and we found + + + align:start position:0% +where you're going to go to and we found +was pretty surprising and that is that + + align:start position:0% +was pretty surprising and that is that + + + align:start position:0% +was pretty surprising and that is that +you might think well if you shut off + + align:start position:0% +you might think well if you shut off + + + align:start position:0% +you might think well if you shut off +hippocampal output right you turn off + + align:start position:0% +hippocampal output right you turn off + + + align:start position:0% +hippocampal output right you turn off +the campus you're gonna get an + + align:start position:0% +the campus you're gonna get an + + + align:start position:0% +the campus you're gonna get an +impairment it's just like if you you + + align:start position:0% +impairment it's just like if you you + + + align:start position:0% +impairment it's just like if you you +know the examples that I gave of + + align:start position:0% +know the examples that I gave of + + + align:start position:0% +know the examples that I gave of +suggesting hippocampus prefrontal cortex + + align:start position:0% +suggesting hippocampus prefrontal cortex + + + align:start position:0% +suggesting hippocampus prefrontal cortex +control most of those come from lesion + + align:start position:0% +control most of those come from lesion + + + align:start position:0% +control most of those come from lesion +studies you damage that the campus + + align:start position:0% +studies you damage that the campus + + + align:start position:0% +studies you damage that the campus +animal can't find his way around so if + + align:start position:0% +animal can't find his way around so if + + + align:start position:0% +animal can't find his way around so if +you were to optogenetic aliy lesion or + + align:start position:0% +you were to optogenetic aliy lesion or + + + align:start position:0% +you were to optogenetic aliy lesion or +turn off the epic campus you might + + align:start position:0% +turn off the epic campus you might + + + align:start position:0% +turn off the epic campus you might +imagine okay animals won't be able to + + align:start position:0% +imagine okay animals won't be able to + + + align:start position:0% +imagine okay animals won't be able to +find their way around so you could ask + + align:start position:0% +find their way around so you could ask + + + align:start position:0% +find their way around so you could ask +this experiment is going to identify + + align:start position:0% +this experiment is going to identify + + + align:start position:0% +this experiment is going to identify +which phase and you know which + + align:start position:0% +which phase and you know which + + + align:start position:0% +which phase and you know which +behavioral phase are most effective in + + align:start position:0% +behavioral phase are most effective in + + + align:start position:0% +behavioral phase are most effective in +disrupting performance but what we + + align:start position:0% +disrupting performance but what we + + + align:start position:0% +disrupting performance but what we +actually found was when you selectively + + align:start position:0% +actually found was when you selectively + + + align:start position:0% +actually found was when you selectively +inhibit activity at different phases you + + align:start position:0% +inhibit activity at different phases you + + + align:start position:0% +inhibit activity at different phases you +actually get an enhancement of + + align:start position:0% +actually get an enhancement of + + + align:start position:0% +actually get an enhancement of +performance they get better and it + + align:start position:0% +performance they get better and it + + + align:start position:0% +performance they get better and it +depended not there wasn't just one phase + + align:start position:0% +depended not there wasn't just one phase + + + align:start position:0% +depended not there wasn't just one phase +a good phase in a bad phase but both of + + align:start position:0% +a good phase in a bad phase but both of + + + align:start position:0% +a good phase in a bad phase but both of +the peak and the trough were both + + align:start position:0% +the peak and the trough were both + + + align:start position:0% +the peak and the trough were both +effective in enhancing performance but + + align:start position:0% +effective in enhancing performance but + + + align:start position:0% +effective in enhancing performance but +only when applied at certain behavioral + + align:start position:0% +only when applied at certain behavioral + + + align:start position:0% +only when applied at certain behavioral +phases in fact there was this double + + align:start position:0% +phases in fact there was this double + + + align:start position:0% +phases in fact there was this double +dissociation and that is that trough + + align:start position:0% +dissociation and that is that trough + + + align:start position:0% +dissociation and that is that trough +stimulation when applied here so when + + align:start position:0% +stimulation when applied here so when + + + align:start position:0% +stimulation when applied here so when +you stimulate in the trough + + align:start position:0% +you stimulate in the trough + + + align:start position:0% +you stimulate in the trough +in the retrieval segment animals got + + align:start position:0% +in the retrieval segment animals got + + + align:start position:0% +in the retrieval segment animals got +better when you stimulate at the peak + + align:start position:0% +better when you stimulate at the peak + + + align:start position:0% +better when you stimulate at the peak +and the encoding segment animals got + + align:start position:0% +and the encoding segment animals got + + + align:start position:0% +and the encoding segment animals got +better so it wasn't that the peak is + + align:start position:0% +better so it wasn't that the peak is + + + align:start position:0% +better so it wasn't that the peak is +good or the trough is Goods the peak the + + align:start position:0% +good or the trough is Goods the peak the + + + align:start position:0% +good or the trough is Goods the peak the +peak is good during retrieval and the + + align:start position:0% +peak is good during retrieval and the + + + align:start position:0% +peak is good during retrieval and the +trough is good during encoding so what + + align:start position:0% +trough is good during encoding so what + + + align:start position:0% +trough is good during encoding so what +it says is the peak and the trough have + + align:start position:0% +it says is the peak and the trough have + + + align:start position:0% +it says is the peak and the trough have +two different functions and if you + + align:start position:0% +two different functions and if you + + + align:start position:0% +two different functions and if you +actually think about what I was showing + + align:start position:0% +actually think about what I was showing + + + align:start position:0% +actually think about what I was showing +before these sequences the sequences + + align:start position:0% +before these sequences the sequences + + + align:start position:0% +before these sequences the sequences +that are going from just behind just in + + align:start position:0% +that are going from just behind just in + + + align:start position:0% +that are going from just behind just in +front of the animal what it says is oh + + align:start position:0% +front of the animal what it says is oh + + + align:start position:0% +front of the animal what it says is oh +yeah these different phases peak and + + align:start position:0% +yeah these different phases peak and + + + align:start position:0% +yeah these different phases peak and +trough you can think of as like past and + + align:start position:0% +trough you can think of as like past and + + + align:start position:0% +trough you can think of as like past and +future and so if I'm sitting over here + + align:start position:0% +future and so if I'm sitting over here + + + align:start position:0% +future and so if I'm sitting over here +in this encoding segment you know what + + align:start position:0% +in this encoding segment you know what + + + align:start position:0% +in this encoding segment you know what +I'm really trying to do is I'm just + + align:start position:0% +I'm really trying to do is I'm just + + + align:start position:0% +I'm really trying to do is I'm just +trying to keep track of where am i right + + align:start position:0% +trying to keep track of where am i right + + + align:start position:0% +trying to keep track of where am i right +now now I may simultaneously also be + + align:start position:0% +now now I may simultaneously also be + + + align:start position:0% +now now I may simultaneously also be +thinking about well where am I going to + + align:start position:0% +thinking about well where am I going to + + + align:start position:0% +thinking about well where am I going to +go + + align:start position:0% +go + + + align:start position:0% +go +but for this task it's not really + + align:start position:0% +but for this task it's not really + + + align:start position:0% +but for this task it's not really +helpful it's not really useful at this + + align:start position:0% +helpful it's not really useful at this + + + align:start position:0% +helpful it's not really useful at this +point I need to focus on where I am + + align:start position:0% +point I need to focus on where I am + + + align:start position:0% +point I need to focus on where I am +right now + + align:start position:0% +right now + + + align:start position:0% +right now +so you can think of simultaneously + + align:start position:0% +so you can think of simultaneously + + + align:start position:0% +so you can think of simultaneously +they're actually these two channels + + align:start position:0% +they're actually these two channels + + + align:start position:0% +they're actually these two channels +where am i where am i where am I going + + align:start position:0% +where am i where am i where am I going + + + align:start position:0% +where am i where am i where am I going +to go and I can enhance performance by + + align:start position:0% +to go and I can enhance performance by + + + align:start position:0% +to go and I can enhance performance by +shutting off or inhibiting the + + align:start position:0% +shutting off or inhibiting the + + + align:start position:0% +shutting off or inhibiting the +non-relevant one so when I keep I shut + + align:start position:0% +non-relevant one so when I keep I shut + + + align:start position:0% +non-relevant one so when I keep I shut +off the retrieval channel here in the + + align:start position:0% +off the retrieval channel here in the + + + align:start position:0% +off the retrieval channel here in the +encoding I get better it's like focusing + + align:start position:0% +encoding I get better it's like focusing + + + align:start position:0% +encoding I get better it's like focusing +attention it's like you know it's like + + align:start position:0% +attention it's like you know it's like + + + align:start position:0% +attention it's like you know it's like +pay attention to what you're doing now + + align:start position:0% +pay attention to what you're doing now + + + align:start position:0% +pay attention to what you're doing now +stop thinking about stuff + + align:start position:0% +stop thinking about stuff + + + align:start position:0% +stop thinking about stuff +similarly when I'm here in the retrieval + + align:start position:0% +similarly when I'm here in the retrieval + + + align:start position:0% +similarly when I'm here in the retrieval +segment I'm also encoding I'm trying to + + align:start position:0% +segment I'm also encoding I'm trying to + + + align:start position:0% +segment I'm also encoding I'm trying to +keep track of where I am as well as + + align:start position:0% +keep track of where I am as well as + + + align:start position:0% +keep track of where I am as well as +think about where I'm going to thing is + + align:start position:0% +think about where I'm going to thing is + + + align:start position:0% +think about where I'm going to thing is +keeping track of where I am here it's + + align:start position:0% +keeping track of where I am here it's + + + align:start position:0% +keeping track of where I am here it's +not relevant for the task it might be + + align:start position:0% +not relevant for the task it might be + + + align:start position:0% +not relevant for the task it might be +broadly relevant for the animal but it's + + align:start position:0% +broadly relevant for the animal but it's + + + align:start position:0% +broadly relevant for the animal but it's +not relevant this test so when I shut + + align:start position:0% +not relevant this test so when I shut + + + align:start position:0% +not relevant this test so when I shut +off I turn off that encoding channel I'm + + align:start position:0% +off I turn off that encoding channel I'm + + + align:start position:0% +off I turn off that encoding channel I'm +able to enhance the retrieval + + align:start position:0% +able to enhance the retrieval + + + align:start position:0% +able to enhance the retrieval +information that goes out so it says it + + align:start position:0% +information that goes out so it says it + + + align:start position:0% +information that goes out so it says it +doesn't this is not I mean you might + + align:start position:0% +doesn't this is not I mean you might + + + align:start position:0% +doesn't this is not I mean you might +interpret this thing oh so this is how + + align:start position:0% +interpret this thing oh so this is how + + + align:start position:0% +interpret this thing oh so this is how +we can improve memory by selectively + + align:start position:0% +we can improve memory by selectively + + + align:start position:0% +we can improve memory by selectively +shutting off the hippocampus well you + + align:start position:0% +shutting off the hippocampus well you + + + align:start position:0% +shutting off the hippocampus well you +know this is not a strategy for general + + align:start position:0% +know this is not a strategy for general + + + align:start position:0% +know this is not a strategy for general +cognitive enhancement they keep the + + align:start position:0% +cognitive enhancement they keep the + + + align:start position:0% +cognitive enhancement they keep the +campus is working much better when all + + align:start position:0% +campus is working much better when all + + + align:start position:0% +campus is working much better when all +these phases are in operation and that's + + align:start position:0% +these phases are in operation and that's + + + align:start position:0% +these phases are in operation and that's +because the epic campus is not designed + + align:start position:0% +because the epic campus is not designed + + + align:start position:0% +because the epic campus is not designed +to solve this task if the camp is + + align:start position:0% +to solve this task if the camp is + + + align:start position:0% +to solve this task if the camp is +designed to solve the broader task is + + align:start position:0% +designed to solve the broader task is + + + align:start position:0% +designed to solve the broader task is +trying to figure out + + align:start position:0% +trying to figure out + + + align:start position:0% +trying to figure out +this task relevant to all the other + + align:start position:0% +this task relevant to all the other + + + align:start position:0% +this task relevant to all the other +things that I have to do as you're + + align:start position:0% +things that I have to do as you're + + + align:start position:0% +things that I have to do as you're +trying to integrate this information + + align:start position:0% +trying to integrate this information + + + align:start position:0% +trying to integrate this information +into all the other information you have + + align:start position:0% +into all the other information you have + + + align:start position:0% +into all the other information you have +and that requires connecting sort of + + align:start position:0% +and that requires connecting sort of + + + align:start position:0% +and that requires connecting sort of +connecting the encoding and retrieval + + align:start position:0% +connecting the encoding and retrieval + + + align:start position:0% +connecting the encoding and retrieval +you really need to have all those pieces + + align:start position:0% +you really need to have all those pieces + + + align:start position:0% +you really need to have all those pieces +of information available but it does + + align:start position:0% +of information available but it does + + + align:start position:0% +of information available but it does +point out that one can actually + + align:start position:0% +point out that one can actually + + + align:start position:0% +point out that one can actually +dissociate the function of information + + align:start position:0% +dissociate the function of information + + + align:start position:0% +dissociate the function of information +in these two different phases the phase + + align:start position:0% +in these two different phases the phase + + + align:start position:0% +in these two different phases the phase +actually matters and it matters at the + + align:start position:0% +actually matters and it matters at the + + + align:start position:0% +actually matters and it matters at the +level of high level behavior + + align:start position:0% +level of high level behavior + + + align:start position:0% +level of high level behavior +decision-making it's not just a it's not + + align:start position:0% +decision-making it's not just a it's not + + + align:start position:0% +decision-making it's not just a it's not +just a idiosyncrasy or artifact of you + + align:start position:0% +just a idiosyncrasy or artifact of you + + + align:start position:0% +just a idiosyncrasy or artifact of you +know excitability as a function of phase + + align:start position:0% +know excitability as a function of phase + + + align:start position:0% +know excitability as a function of phase +this is really how information is being + + align:start position:0% +this is really how information is being + + + align:start position:0% +this is really how information is being +used + + align:start position:0% + + + + align:start position:0% + +you \ No newline at end of file diff --git a/w6R6V1Mpz7s.txt b/w6R6V1Mpz7s.txt new file mode 100644 index 0000000000000000000000000000000000000000..d4fdec7ec5bdc865d0bff4da0aaa3a34de5bfe29 --- /dev/null +++ b/w6R6V1Mpz7s.txt @@ -0,0 +1,9923 @@ +align:start position:0% + +okay why don't we get + + align:start position:0% +okay why don't we get + + + align:start position:0% +okay why don't we get +started so um before going back to + + align:start position:0% +started so um before going back to + + + align:start position:0% +started so um before going back to +talking about more kinds of power + + align:start position:0% +talking about more kinds of power + + + align:start position:0% +talking about more kinds of power +electronic circuits I wanted to spend + + align:start position:0% +electronic circuits I wanted to spend + + + align:start position:0% +electronic circuits I wanted to spend +one lecture uh talking about heat + + align:start position:0% +one lecture uh talking about heat + + + align:start position:0% +one lecture uh talking about heat +transfer and sort of how you model and + + align:start position:0% +transfer and sort of how you model and + + + align:start position:0% +transfer and sort of how you model and +design thermal system systems and this + + align:start position:0% +design thermal system systems and this + + + align:start position:0% +design thermal system systems and this +is uh principles of Power Electronics + + align:start position:0% +is uh principles of Power Electronics + + + align:start position:0% +is uh principles of Power Electronics +chapter + + align:start position:0% +chapter + + + align:start position:0% +chapter +25 um now to be clear you can spend an + + align:start position:0% +25 um now to be clear you can spend an + + + align:start position:0% +25 um now to be clear you can spend an +entire course or for that matter + + align:start position:0% +entire course or for that matter + + + align:start position:0% +entire course or for that matter +multiple entire courses studying uh heat + + align:start position:0% +multiple entire courses studying uh heat + + + align:start position:0% +multiple entire courses studying uh heat +transfer and the ways to do that and + + align:start position:0% +transfer and the ways to do that and + + + align:start position:0% +transfer and the ways to do that and +clearly we don't have time to do that + + align:start position:0% +clearly we don't have time to do that + + + align:start position:0% +clearly we don't have time to do that +here so what I'm going to attempt to do + + align:start position:0% +here so what I'm going to attempt to do + + + align:start position:0% +here so what I'm going to attempt to do +in this lecture is give you just enough + + align:start position:0% +in this lecture is give you just enough + + + align:start position:0% +in this lecture is give you just enough +information to be dangerous okay in that + + align:start position:0% +information to be dangerous okay in that + + + align:start position:0% +information to be dangerous okay in that +a lot of the things we need to do as a + + align:start position:0% +a lot of the things we need to do as a + + + align:start position:0% +a lot of the things we need to do as a +Power Electronics designer let us offset + + align:start position:0% +Power Electronics designer let us offset + + + align:start position:0% +Power Electronics designer let us offset +some of the sort of the detailed + + align:start position:0% +some of the sort of the detailed + + + align:start position:0% +some of the sort of the detailed +computational or you know deep + + align:start position:0% +computational or you know deep + + + align:start position:0% +computational or you know deep +analytical modeling onto uh heat sync + + align:start position:0% +analytical modeling onto uh heat sync + + + align:start position:0% +analytical modeling onto uh heat sync +designers and other people and what we + + align:start position:0% +designers and other people and what we + + + align:start position:0% +designers and other people and what we +need to know is enough information about + + align:start position:0% +need to know is enough information about + + + align:start position:0% +need to know is enough information about +how to model these things that we can + + align:start position:0% +how to model these things that we can + + + align:start position:0% +how to model these things that we can +predict things like temperature rises + + align:start position:0% +predict things like temperature rises + + + align:start position:0% +predict things like temperature rises +and select the kind of correct + + align:start position:0% +and select the kind of correct + + + align:start position:0% +and select the kind of correct +components and that's what we're going + + align:start position:0% +components and that's what we're going + + + align:start position:0% +components and that's what we're going +to try to get to + + align:start position:0% +to try to get to + + + align:start position:0% +to try to get to +today okay now if we think about heat + + align:start position:0% +today okay now if we think about heat + + + align:start position:0% +today okay now if we think about heat +transfer there's sort of and and first + + align:start position:0% +transfer there's sort of and and first + + + align:start position:0% +transfer there's sort of and and first +of all why am I obsessed about this it's + + align:start position:0% +of all why am I obsessed about this it's + + + align:start position:0% +of all why am I obsessed about this it's +because you know we're going to despite + + align:start position:0% +because you know we're going to despite + + + align:start position:0% +because you know we're going to despite +our best attempts we're going to + + align:start position:0% +our best attempts we're going to + + + align:start position:0% +our best attempts we're going to +dissipate some power in our devices in + + align:start position:0% +dissipate some power in our devices in + + + align:start position:0% +dissipate some power in our devices in +our components and if I want to make + + align:start position:0% +our components and if I want to make + + + align:start position:0% +our components and if I want to make +something really high power density I've + + align:start position:0% +something really high power density I've + + + align:start position:0% +something really high power density I've +really first of all got to minimize how + + align:start position:0% +really first of all got to minimize how + + + align:start position:0% +really first of all got to minimize how +much heat I + + align:start position:0% +much heat I + + + align:start position:0% +much heat I +dissipate but in the end I've also got + + align:start position:0% +dissipate but in the end I've also got + + + align:start position:0% +dissipate but in the end I've also got +to take whatever heat I dissipate and + + align:start position:0% +to take whatever heat I dissipate and + + + align:start position:0% +to take whatever heat I dissipate and +get it out of the system right and how + + align:start position:0% +get it out of the system right and how + + + align:start position:0% +get it out of the system right and how +good a job I do of getting it away from + + align:start position:0% +good a job I do of getting it away from + + + align:start position:0% +good a job I do of getting it away from +the components and keeping their + + align:start position:0% +the components and keeping their + + + align:start position:0% +the components and keeping their +temperature rise low says a lot about + + align:start position:0% +temperature rise low says a lot about + + + align:start position:0% +temperature rise low says a lot about +you know how high performance power + + align:start position:0% +you know how high performance power + + + align:start position:0% +you know how high performance power +converter I can build okay now so let's + + align:start position:0% +converter I can build okay now so let's + + + align:start position:0% +converter I can build okay now so let's +assume we're going to dissipate a + + align:start position:0% +assume we're going to dissipate a + + + align:start position:0% +assume we're going to dissipate a +certain amount of power and ask how do I + + align:start position:0% +certain amount of power and ask how do I + + + align:start position:0% +certain amount of power and ask how do I +get the heat out of my system okay and + + align:start position:0% +get the heat out of my system okay and + + + align:start position:0% +get the heat out of my system okay and +there's really three fundamental ways uh + + align:start position:0% +there's really three fundamental ways uh + + + align:start position:0% +there's really three fundamental ways uh +you can do that you can do it through + + align:start position:0% + + + + align:start position:0% + +conduction okay conduction is just + + align:start position:0% +conduction okay conduction is just + + + align:start position:0% +conduction okay conduction is just +simply you know if I if I think of uh + + align:start position:0% +simply you know if I if I think of uh + + + align:start position:0% +simply you know if I if I think of uh +heat as being vibrations of particles + + align:start position:0% +heat as being vibrations of particles + + + align:start position:0% +heat as being vibrations of particles +right I can let the heat conduct through + + align:start position:0% +right I can let the heat conduct through + + + align:start position:0% +right I can let the heat conduct through +some heat conductor and be carried away + + align:start position:0% +some heat conductor and be carried away + + + align:start position:0% +some heat conductor and be carried away +so some physical element like a piece of + + align:start position:0% +so some physical element like a piece of + + + align:start position:0% +so some physical element like a piece of +metal will carry heat along it okay I + + align:start position:0% +metal will carry heat along it okay I + + + align:start position:0% +metal will carry heat along it okay I +can do it by + + align:start position:0% + + + + align:start position:0% + +convection right I transfer heat to some + + align:start position:0% +convection right I transfer heat to some + + + align:start position:0% +convection right I transfer heat to some +moving fluid that could be air or water + + align:start position:0% +moving fluid that could be air or water + + + align:start position:0% +moving fluid that could be air or water +and I let the fluid carry the heat + + align:start position:0% +and I let the fluid carry the heat + + + align:start position:0% +and I let the fluid carry the heat +away or I could do it by + + align:start position:0% + + + + align:start position:0% + +radiation right if I make something hot + + align:start position:0% +radiation right if I make something hot + + + align:start position:0% +radiation right if I make something hot +it emits photons at whatever wavelength + + align:start position:0% +it emits photons at whatever wavelength + + + align:start position:0% +it emits photons at whatever wavelength +right it emits electromagnetic radiation + + align:start position:0% +right it emits electromagnetic radiation + + + align:start position:0% +right it emits electromagnetic radiation +that carries the heat away from my + + align:start position:0% +that carries the heat away from my + + + align:start position:0% +that carries the heat away from my +device okay and you know depending upon + + align:start position:0% +device okay and you know depending upon + + + align:start position:0% +device okay and you know depending upon +the application all three of these can + + align:start position:0% +the application all three of these can + + + align:start position:0% +the application all three of these can +be + + align:start position:0% +be + + + align:start position:0% +be +important however um you know + + align:start position:0% +important however um you know + + + align:start position:0% +important however um you know +radiation if I looked at the rate of + + align:start position:0% +radiation if I looked at the rate of + + + align:start position:0% +radiation if I looked at the rate of +heat + + align:start position:0% +heat + + + align:start position:0% +heat +transfer so this is sort of heat power + + align:start position:0% +transfer so this is sort of heat power + + + align:start position:0% +transfer so this is sort of heat power +being transferred tends to be + + align:start position:0% +being transferred tends to be + + + align:start position:0% +being transferred tends to be +proportional to the source thing that's + + align:start position:0% +proportional to the source thing that's + + + align:start position:0% +proportional to the source thing that's +delivering the heat away to the fourth + + align:start position:0% +delivering the heat away to the fourth + + + align:start position:0% +delivering the heat away to the fourth +power minus the environment around it to + + align:start position:0% +power minus the environment around it to + + + align:start position:0% +power minus the environment around it to +the fourth power okay so this High to + + align:start position:0% +the fourth power okay so this High to + + + align:start position:0% +the fourth power okay so this High to +the fourth power means that when things + + align:start position:0% +the fourth power means that when things + + + align:start position:0% +the fourth power means that when things +get really + + align:start position:0% +get really + + + align:start position:0% +get really +hot radiation really dominates heat + + align:start position:0% +hot radiation really dominates heat + + + align:start position:0% +hot radiation really dominates heat +transfer but for most terrestrial + + align:start position:0% +transfer but for most terrestrial + + + align:start position:0% +transfer but for most terrestrial +applications it's not the highest it's + + align:start position:0% +applications it's not the highest it's + + + align:start position:0% +applications it's not the highest it's +not the most important thing right so if + + align:start position:0% +not the most important thing right so if + + + align:start position:0% +not the most important thing right so if +I have an incandescent light bulb and + + align:start position:0% +I have an incandescent light bulb and + + + align:start position:0% +I have an incandescent light bulb and +it's really really hot right then yeah a + + align:start position:0% +it's really really hot right then yeah a + + + align:start position:0% +it's really really hot right then yeah a +large part of the energy may get out of + + align:start position:0% +large part of the energy may get out of + + + align:start position:0% +large part of the energy may get out of +it by just radiating away from it okay + + align:start position:0% +it by just radiating away from it okay + + + align:start position:0% +it by just radiating away from it okay +as black body radiation um if + + align:start position:0% +as black body radiation um if + + + align:start position:0% +as black body radiation um if +I'm in a satellite and there's no way + + align:start position:0% +I'm in a satellite and there's no way + + + align:start position:0% +I'm in a satellite and there's no way +for heat to conduct out of the thing and + + align:start position:0% +for heat to conduct out of the thing and + + + align:start position:0% +for heat to conduct out of the thing and +there's no air or anything out for the + + align:start position:0% +there's no air or anything out for the + + + align:start position:0% +there's no air or anything out for the +heat to go into well then eventually all + + align:start position:0% +heat to go into well then eventually all + + + align:start position:0% +heat to go into well then eventually all +the Heat's going to go away from that + + align:start position:0% +the Heat's going to go away from that + + + align:start position:0% +the Heat's going to go away from that +thing by radiation so in those kind of + + align:start position:0% +thing by radiation so in those kind of + + + align:start position:0% +thing by radiation so in those kind of +applications yeah I really May care very + + align:start position:0% +applications yeah I really May care very + + + align:start position:0% +applications yeah I really May care very +heavily about radiation but in most + + align:start position:0% +heavily about radiation but in most + + + align:start position:0% +heavily about radiation but in most +cases it's only a smallish fraction of + + align:start position:0% +cases it's only a smallish fraction of + + + align:start position:0% +cases it's only a smallish fraction of +the heat I'm getting rid of because we + + align:start position:0% +the heat I'm getting rid of because we + + + align:start position:0% +the heat I'm getting rid of because we +don't you know we don't get crazy high + + align:start position:0% +don't you know we don't get crazy high + + + align:start position:0% +don't you know we don't get crazy high +temperatures we don't have thousands of + + align:start position:0% +temperatures we don't have thousands of + + + align:start position:0% +temperatures we don't have thousands of +degrees Kelvin to to remove the + + align:start position:0% +degrees Kelvin to to remove the + + + align:start position:0% +degrees Kelvin to to remove the +heat okay um so let's go back and look + + align:start position:0% +heat okay um so let's go back and look + + + align:start position:0% +heat okay um so let's go back and look +at convection and conduction I'll start + + align:start position:0% +at convection and conduction I'll start + + + align:start position:0% +at convection and conduction I'll start +with + + align:start position:0% +with + + + align:start position:0% +with +conduction okay suppose I + + align:start position:0% +conduction okay suppose I + + + align:start position:0% +conduction okay suppose I +took + + align:start position:0% +took + + + align:start position:0% +took +um actually I I'll just go over here + + align:start position:0% +um actually I I'll just go over here + + + align:start position:0% +um actually I I'll just go over here +suppose I took + + align:start position:0% +suppose I took + + + align:start position:0% +suppose I took +some PL I I'll keep everything 1D and + + align:start position:0% +some PL I I'll keep everything 1D and + + + align:start position:0% +some PL I I'll keep everything 1D and +I'll get + + align:start position:0% +I'll get + + + align:start position:0% +I'll get +some thing that I'll put at temperature + + align:start position:0% +some thing that I'll put at temperature + + + align:start position:0% +some thing that I'll put at temperature +T1 okay and then I'll have some block of + + align:start position:0% +T1 okay and then I'll have some block of + + + align:start position:0% +T1 okay and then I'll have some block of +material + + align:start position:0% + + + + align:start position:0% + +okay okay and I will + + align:start position:0% +okay okay and I will + + + align:start position:0% +okay okay and I will +have a second surface that I will keep a + + align:start position:0% +have a second surface that I will keep a + + + align:start position:0% +have a second surface that I will keep a +temperature + + align:start position:0% +temperature + + + align:start position:0% +temperature +T2 right and in between them I have some + + align:start position:0% +T2 right and in between them I have some + + + align:start position:0% +T2 right and in between them I have some +material through which Heat's going to + + align:start position:0% +material through which Heat's going to + + + align:start position:0% +material through which Heat's going to +flow it's going to conduct + + align:start position:0% +flow it's going to conduct + + + align:start position:0% +flow it's going to conduct +okay and this material whatever it + + align:start position:0% +okay and this material whatever it + + + align:start position:0% +okay and this material whatever it +is um might have some cross-sectional + + align:start position:0% +is um might have some cross-sectional + + + align:start position:0% +is um might have some cross-sectional +area + + align:start position:0% +area + + + align:start position:0% +area +a and it might be transferring heat + + align:start position:0% +a and it might be transferring heat + + + align:start position:0% +a and it might be transferring heat +through some length L right and in this + + align:start position:0% +through some length L right and in this + + + align:start position:0% +through some length L right and in this +kind of situation with 1D heat transfer + + align:start position:0% +kind of situation with 1D heat transfer + + + align:start position:0% +kind of situation with 1D heat transfer +you for many materials what you get is + + align:start position:0% +you for many materials what you get is + + + align:start position:0% +you for many materials what you get is +the following relationship + + align:start position:0% +the following relationship + + + align:start position:0% +the following relationship +um Q that's the the amount of heat + + align:start position:0% +um Q that's the the amount of heat + + + align:start position:0% +um Q that's the the amount of heat +transferred is um proportional to the + + align:start position:0% +transferred is um proportional to the + + + align:start position:0% +transferred is um proportional to the +temperature difference T1 minus + + align:start position:0% +temperature difference T1 minus + + + align:start position:0% +temperature difference T1 minus +T2 okay um times the um cross-sectional + + align:start position:0% +T2 okay um times the um cross-sectional + + + align:start position:0% +T2 okay um times the um cross-sectional +area divided by the thermal resistance + + align:start position:0% +area divided by the thermal resistance + + + align:start position:0% +area divided by the thermal resistance +rth and divided by the length right so + + align:start position:0% +rth and divided by the length right so + + + align:start position:0% +rth and divided by the length right so +if I have more cross-sectional area more + + align:start position:0% +if I have more cross-sectional area more + + + align:start position:0% +if I have more cross-sectional area more +heat flows if I have to transfer it + + align:start position:0% +heat flows if I have to transfer it + + + align:start position:0% +heat flows if I have to transfer it +through a thicker piece of material the + + align:start position:0% +through a thicker piece of material the + + + align:start position:0% +through a thicker piece of material the +heat flow goes down and this + + align:start position:0% +heat flow goes down and this + + + align:start position:0% +heat flow goes down and this +proportionality constant is called the + + align:start position:0% +proportionality constant is called the + + + align:start position:0% +proportionality constant is called the +thermal resistivity of the material okay + + align:start position:0% +thermal resistivity of the material okay + + + align:start position:0% +thermal resistivity of the material okay +I could rewrite this as um T1 minus T2 + + align:start position:0% +I could rewrite this as um T1 minus T2 + + + align:start position:0% +I could rewrite this as um T1 minus T2 +divided by rth * L / a that would be + + align:start position:0% +divided by rth * L / a that would be + + + align:start position:0% +divided by rth * L / a that would be +another way to write this okay so this + + align:start position:0% +another way to write this okay so this + + + align:start position:0% +another way to write this okay so this +would reflect how heat this would be + + align:start position:0% +would reflect how heat this would be + + + align:start position:0% +would reflect how heat this would be +reflect conduction + + align:start position:0% + + + + align:start position:0% + +of heat okay in steady state + + align:start position:0% +of heat okay in steady state + + + align:start position:0% +of heat okay in steady state +okay + + align:start position:0% + + + + align:start position:0% + +um this relationship and this is sort of + + align:start position:0% +um this relationship and this is sort of + + + align:start position:0% +um this relationship and this is sort of +a bulk relationship right I could create + + align:start position:0% +a bulk relationship right I could create + + + align:start position:0% +a bulk relationship right I could create +an A A an incremental relationship uh + + align:start position:0% +an A A an incremental relationship uh + + + align:start position:0% +an A A an incremental relationship uh +which would be you know Q is equal to + + align:start position:0% +which would be you know Q is equal to + + + align:start position:0% +which would be you know Q is equal to +minus a over row t d D + + align:start position:0% + + + + align:start position:0% + +TDX okay that would be you know if I + + align:start position:0% +TDX okay that would be you know if I + + + align:start position:0% +TDX okay that would be you know if I +treated everything as a little increment + + align:start position:0% +treated everything as a little increment + + + align:start position:0% +treated everything as a little increment +in space and if I want to start doing 4A + + align:start position:0% +in space and if I want to start doing 4A + + + align:start position:0% +in space and if I want to start doing 4A +heat transfer I get into um these kind + + align:start position:0% +heat transfer I get into um these kind + + + align:start position:0% +heat transfer I get into um these kind +of + + align:start position:0% +of + + + align:start position:0% +of +um kind of differential equations + + align:start position:0% +um kind of differential equations + + + align:start position:0% +um kind of differential equations +descriptions but for a bulk piece of + + align:start position:0% +descriptions but for a bulk piece of + + + align:start position:0% +descriptions but for a bulk piece of +element we can write it like this okay + + align:start position:0% +element we can write it like this okay + + + align:start position:0% +element we can write it like this okay +this relationship where q q is my heat + + align:start position:0% +this relationship where q q is my heat + + + align:start position:0% +this relationship where q q is my heat +flow right so Q is whatever Heat flowing + + align:start position:0% +flow right so Q is whatever Heat flowing + + + align:start position:0% +flow right so Q is whatever Heat flowing +this way okay sort of suggests circuit + + align:start position:0% +this way okay sort of suggests circuit + + + align:start position:0% +this way okay sort of suggests circuit +analog right where here's my circuit + + align:start position:0% +analog right where here's my circuit + + + align:start position:0% +analog right where here's my circuit +model I have some temperature + + align:start position:0% +model I have some temperature + + + align:start position:0% +model I have some temperature +Source + + align:start position:0% +Source + + + align:start position:0% +Source +T1 and another temperature Source or + + align:start position:0% +T1 and another temperature Source or + + + align:start position:0% +T1 and another temperature Source or +temperature sync T2 right so temperature + + align:start position:0% +temperature sync T2 right so temperature + + + align:start position:0% +temperature sync T2 right so temperature +now it means a voltage source here means + + align:start position:0% +now it means a voltage source here means + + + align:start position:0% +now it means a voltage source here means +constant temperature okay and then + + align:start position:0% +constant temperature okay and then + + + align:start position:0% +constant temperature okay and then +there's between them some thermal + + align:start position:0% +there's between them some thermal + + + align:start position:0% +there's between them some thermal +resistance rth + + align:start position:0% +resistance rth + + + align:start position:0% +resistance rth +which is equal to row T * L over + + align:start position:0% +which is equal to row T * L over + + + align:start position:0% +which is equal to row T * L over +a okay and that has the same form as an + + align:start position:0% +a okay and that has the same form as an + + + align:start position:0% +a okay and that has the same form as an +electrical resistor okay and then my + + align:start position:0% +electrical resistor okay and then my + + + align:start position:0% +electrical resistor okay and then my +heat flow + + align:start position:0% +heat flow + + + align:start position:0% +heat flow +Q is sort of the current flowing around + + align:start position:0% +Q is sort of the current flowing around + + + align:start position:0% +Q is sort of the current flowing around +this Loop and + + align:start position:0% +this Loop and + + + align:start position:0% +this Loop and +here right I have + + align:start position:0% +here right I have + + + align:start position:0% +here right I have +some point to which these temperatures + + align:start position:0% +some point to which these temperatures + + + align:start position:0% +some point to which these temperatures +are referenced ideally speaking this + + align:start position:0% +are referenced ideally speaking this + + + align:start position:0% +are referenced ideally speaking this +should be absolute zero in practice + + align:start position:0% +should be absolute zero in practice + + + align:start position:0% +should be absolute zero in practice +people often just just represent + + align:start position:0% +people often just just represent + + + align:start position:0% +people often just just represent +reference it to ambient and pretend + + align:start position:0% +reference it to ambient and pretend + + + align:start position:0% +reference it to ambient and pretend +ambient is the equivalent of absolute + + align:start position:0% +ambient is the equivalent of absolute + + + align:start position:0% +ambient is the equivalent of absolute +zero it' be kind of like having an + + align:start position:0% +zero it' be kind of like having an + + + align:start position:0% +zero it' be kind of like having an +offset from off absolute zero okay any + + align:start position:0% +offset from off absolute zero okay any + + + align:start position:0% +offset from off absolute zero okay any +questions about that structure you get + + align:start position:0% +questions about that structure you get + + + align:start position:0% +questions about that structure you get +you know if you Analyze This circuit you + + align:start position:0% +you know if you Analyze This circuit you + + + align:start position:0% +you know if you Analyze This circuit you +get exactly this + + align:start position:0% +get exactly this + + + align:start position:0% +get exactly this +relationship Okay the reason this works + + align:start position:0% +relationship Okay the reason this works + + + align:start position:0% +relationship Okay the reason this works +is sort of temperature is conserved + + align:start position:0% +is sort of temperature is conserved + + + align:start position:0% +is sort of temperature is conserved +going around any Loop right if I measure + + align:start position:0% +going around any Loop right if I measure + + + align:start position:0% +going around any Loop right if I measure +temperature differences around a loop I + + align:start position:0% +temperature differences around a loop I + + + align:start position:0% +temperature differences around a loop I +would get zero and you know if I + + align:start position:0% +would get zero and you know if I + + + align:start position:0% +would get zero and you know if I +consider heat inputs and Heat transfers + + align:start position:0% +consider heat inputs and Heat transfers + + + align:start position:0% +consider heat inputs and Heat transfers +conservation of power is sort of the + + align:start position:0% +conservation of power is sort of the + + + align:start position:0% +conservation of power is sort of the +equivalent of KCl in the circuit model + + align:start position:0% +equivalent of KCl in the circuit model + + + align:start position:0% +equivalent of KCl in the circuit model +so I you know I'm showing you a + + align:start position:0% +so I you know I'm showing you a + + + align:start position:0% +so I you know I'm showing you a +simplified circuit model for a very + + align:start position:0% +simplified circuit model for a very + + + align:start position:0% +simplified circuit model for a very +particular kind of heat transfer but you + + align:start position:0% +particular kind of heat transfer but you + + + align:start position:0% +particular kind of heat transfer but you +can use this model to represent heat + + align:start position:0% +can use this model to represent heat + + + align:start position:0% +can use this model to represent heat +transfers in a variety of conditions any + + align:start position:0% +transfers in a variety of conditions any + + + align:start position:0% +transfers in a variety of conditions any +questions about + + align:start position:0% + + + + align:start position:0% + +that so okay so I should say by the way + + align:start position:0% +that so okay so I should say by the way + + + align:start position:0% +that so okay so I should say by the way +Q is in Watts + + align:start position:0% +Q is in Watts + + + align:start position:0% +Q is in Watts +right that's the heat flow in Watts T is + + align:start position:0% +right that's the heat flow in Watts T is + + + align:start position:0% +right that's the heat flow in Watts T is +in kelvin or often people use it in + + align:start position:0% +in kelvin or often people use it in + + + align:start position:0% +in kelvin or often people use it in +degrees + + align:start position:0% +degrees + + + align:start position:0% +degrees +cels and + + align:start position:0% +cels and + + + align:start position:0% +cels and +rth ends up having units of degree C per + + align:start position:0% +rth ends up having units of degree C per + + + align:start position:0% +rth ends up having units of degree C per +watt or kelvin per + + align:start position:0% +watt or kelvin per + + + align:start position:0% +watt or kelvin per +watt + + align:start position:0% +watt + + + align:start position:0% +watt +okay all right + + align:start position:0% +okay all right + + + align:start position:0% +okay all right +um in this regard thermal resistance is + + align:start position:0% +um in this regard thermal resistance is + + + align:start position:0% +um in this regard thermal resistance is +very like regular resistance right + + align:start position:0% +very like regular resistance right + + + align:start position:0% +very like regular resistance right +because if I think about a regular + + align:start position:0% +because if I think about a regular + + + align:start position:0% +because if I think about a regular +resistor right if I make the resistor + + align:start position:0% +resistor right if I make the resistor + + + align:start position:0% +resistor right if I make the resistor +proportionately longer the thermal + + align:start position:0% +proportionately longer the thermal + + + align:start position:0% +proportionately longer the thermal +resistance goes up if I increase the + + align:start position:0% +resistance goes up if I increase the + + + align:start position:0% +resistance goes up if I increase the +cross-sectional area the thermal + + align:start position:0% +cross-sectional area the thermal + + + align:start position:0% +cross-sectional area the thermal +resistance goes down and here all I have + + align:start position:0% +resistance goes down and here all I have + + + align:start position:0% +resistance goes down and here all I have +is thermal resistivity instead of + + align:start position:0% +is thermal resistivity instead of + + + align:start position:0% +is thermal resistivity instead of +electrical resistivity so the form of + + align:start position:0% +electrical resistivity so the form of + + + align:start position:0% +electrical resistivity so the form of +the relationships are exactly the same + + align:start position:0% +the relationships are exactly the same + + + align:start position:0% +the relationships are exactly the same +all right so um you know basically we + + align:start position:0% +all right so um you know basically we + + + align:start position:0% +all right so um you know basically we +can assume all of our devices in steady + + align:start position:0% +can assume all of our devices in steady + + + align:start position:0% +can assume all of our devices in steady +state have some thermal resistances we + + align:start position:0% +state have some thermal resistances we + + + align:start position:0% +state have some thermal resistances we +can put Power into the system if we know + + align:start position:0% +can put Power into the system if we know + + + align:start position:0% +can put Power into the system if we know +some fixed temperatures like some + + align:start position:0% +some fixed temperatures like some + + + align:start position:0% +some fixed temperatures like some +ambient temperatures we can create a + + align:start position:0% +ambient temperatures we can create a + + + align:start position:0% +ambient temperatures we can create a +circuit and then analyze what our heat + + align:start position:0% +circuit and then analyze what our heat + + + align:start position:0% +circuit and then analyze what our heat +flows will look + + align:start position:0% + + + + align:start position:0% + +like this is conduction what might my + + align:start position:0% +like this is conduction what might my + + + align:start position:0% +like this is conduction what might my +other uh means of transferring energy a + + align:start position:0% +other uh means of transferring energy a + + + align:start position:0% +other uh means of transferring energy a +heat energy look like well my my other + + align:start position:0% +heat energy look like well my my other + + + align:start position:0% +heat energy look like well my my other +means of heat transferring energy might + + align:start position:0% +means of heat transferring energy might + + + align:start position:0% +means of heat transferring energy might +be something like this right I've got + + align:start position:0% +be something like this right I've got + + + align:start position:0% +be something like this right I've got +some + + align:start position:0% +some + + + align:start position:0% +some +structure which you know has Heat going + + align:start position:0% +structure which you know has Heat going + + + align:start position:0% +structure which you know has Heat going +into it it and then some fluid going + + align:start position:0% +into it it and then some fluid going + + + align:start position:0% +into it it and then some fluid going +over + + align:start position:0% +over + + + align:start position:0% +over +it you know this could be a flow of air + + align:start position:0% +it you know this could be a flow of air + + + align:start position:0% +it you know this could be a flow of air +or a flow of water or something like + + align:start position:0% +or a flow of water or something like + + + align:start position:0% +or a flow of water or something like +that and what we expect to happen is the + + align:start position:0% +that and what we expect to happen is the + + + align:start position:0% +that and what we expect to happen is the +heat is going to come out of whatever + + align:start position:0% +heat is going to come out of whatever + + + align:start position:0% +heat is going to come out of whatever +the item is up into the air and then the + + align:start position:0% +the item is up into the air and then the + + + align:start position:0% +the item is up into the air and then the +air is going to carry it away okay so + + align:start position:0% +air is going to carry it away okay so + + + align:start position:0% +air is going to carry it away okay so +I'm going to transfer the heat into the + + align:start position:0% +I'm going to transfer the heat into the + + + align:start position:0% +I'm going to transfer the heat into the +moving fluid and the moving fluid kind + + align:start position:0% +moving fluid and the moving fluid kind + + + align:start position:0% +moving fluid and the moving fluid kind +of walks away with it + + align:start position:0% +of walks away with it + + + align:start position:0% +of walks away with it +okay um what does this look like + + align:start position:0% + + + + align:start position:0% + +um heat transfer for this case looks + + align:start position:0% +um heat transfer for this case looks + + + align:start position:0% +um heat transfer for this case looks +like Q is the heat transfer is equal to + + align:start position:0% +like Q is the heat transfer is equal to + + + align:start position:0% +like Q is the heat transfer is equal to +ha time the temperature of the + + align:start position:0% +ha time the temperature of the + + + align:start position:0% +ha time the temperature of the +surface minus the temperature of the + + align:start position:0% +surface minus the temperature of the + + + align:start position:0% +surface minus the temperature of the +fluid right so if I have some fluid at T + + align:start position:0% + + + + align:start position:0% + +fluid and I have some you know + + align:start position:0% +fluid and I have some you know + + + align:start position:0% +fluid and I have some you know +temperature at the surface T + + align:start position:0% +temperature at the surface T + + + align:start position:0% +temperature at the surface T +surface right the Heat transfer again + + align:start position:0% +surface right the Heat transfer again + + + align:start position:0% +surface right the Heat transfer again +IDE in some range is going to be + + align:start position:0% +IDE in some range is going to be + + + align:start position:0% +IDE in some range is going to be +proportional to the temperature + + align:start position:0% +proportional to the temperature + + + align:start position:0% +proportional to the temperature +difference between the surface of this + + align:start position:0% +difference between the surface of this + + + align:start position:0% +difference between the surface of this +thing and the fluid that's carrying the + + align:start position:0% +thing and the fluid that's carrying the + + + align:start position:0% +thing and the fluid that's carrying the +heat away and this is the so-called uh + + align:start position:0% +heat away and this is the so-called uh + + + align:start position:0% +heat away and this is the so-called uh +wetted + + align:start position:0% + + + + align:start position:0% + +area right this is the area at the + + align:start position:0% +area right this is the area at the + + + align:start position:0% +area right this is the area at the +interface that the the fluid's flowing + + align:start position:0% +interface that the the fluid's flowing + + + align:start position:0% +interface that the the fluid's flowing +over to grab the Heat and carry it away + + align:start position:0% +over to grab the Heat and carry it away + + + align:start position:0% +over to grab the Heat and carry it away +and then this is the heat transfer + + align:start position:0% + + + + align:start position:0% + +coefficient all right now here's where + + align:start position:0% +coefficient all right now here's where + + + align:start position:0% +coefficient all right now here's where +you know it's right + + align:start position:0% +you know it's right + + + align:start position:0% +you know it's right +here is essentially where I'm burying + + align:start position:0% +here is essentially where I'm burying + + + align:start position:0% +here is essentially where I'm burying +all the + + align:start position:0% +all the + + + align:start position:0% +all the +ugliness okay this is where I'm you know + + align:start position:0% +ugliness okay this is where I'm you know + + + align:start position:0% +ugliness okay this is where I'm you know +massively oversimplifying it and the + + align:start position:0% +massively oversimplifying it and the + + + align:start position:0% +massively oversimplifying it and the +reason you can take whole courses in + + align:start position:0% +reason you can take whole courses in + + + align:start position:0% +reason you can take whole courses in +this TR whole courses in this topic is + + align:start position:0% +this TR whole courses in this topic is + + + align:start position:0% +this TR whole courses in this topic is +because you know what is this heat + + align:start position:0% +because you know what is this heat + + + align:start position:0% +because you know what is this heat +transfer coefficient well it depends + + align:start position:0% +transfer coefficient well it depends + + + align:start position:0% +transfer coefficient well it depends +upon is the flow laminer or turbulent it + + align:start position:0% +upon is the flow laminer or turbulent it + + + align:start position:0% +upon is the flow laminer or turbulent it +depends upon all kinds of stuff right + + align:start position:0% +depends upon all kinds of stuff right + + + align:start position:0% +depends upon all kinds of stuff right +and it can even be a fun function of + + align:start position:0% +and it can even be a fun function of + + + align:start position:0% +and it can even be a fun function of +temperatures in the general case Okay um + + align:start position:0% +temperatures in the general case Okay um + + + align:start position:0% +temperatures in the general case Okay um +so you know I have to tell you I'm + + align:start position:0% +so you know I have to tell you I'm + + + align:start position:0% +so you know I have to tell you I'm +telling you this magic number how you + + align:start position:0% +telling you this magic number how you + + + align:start position:0% +telling you this magic number how you +find that magic number is tricky in a + + align:start position:0% +find that magic number is tricky in a + + + align:start position:0% +find that magic number is tricky in a +lot of cases okay what we're going to + + align:start position:0% +lot of cases okay what we're going to + + + align:start position:0% +lot of cases okay what we're going to +see as designers we often don't have to + + align:start position:0% +see as designers we often don't have to + + + align:start position:0% +see as designers we often don't have to +worry about that okay so in this case I + + align:start position:0% +worry about that okay so in this case I + + + align:start position:0% +worry about that okay so in this case I +could kind of have the same model where + + align:start position:0% +could kind of have the same model where + + + align:start position:0% +could kind of have the same model where +I would just say Okay + + align:start position:0% +I would just say Okay + + + align:start position:0% +I would just say Okay +rth is simply equal to ha inverse right + + align:start position:0% +rth is simply equal to ha inverse right + + + align:start position:0% +rth is simply equal to ha inverse right +if I told you the area through which I + + align:start position:0% +if I told you the area through which I + + + align:start position:0% +if I told you the area through which I +was transferring heat and I knew that + + align:start position:0% +was transferring heat and I knew that + + + align:start position:0% +was transferring heat and I knew that +heat transfer + + align:start position:0% +heat transfer + + + align:start position:0% +heat transfer +coefficient great I've got my answer and + + align:start position:0% +coefficient great I've got my answer and + + + align:start position:0% +coefficient great I've got my answer and +I go my Merry way all right so putting + + align:start position:0% +I go my Merry way all right so putting + + + align:start position:0% +I go my Merry way all right so putting +aside that it's difficult to find this + + align:start position:0% +aside that it's difficult to find this + + + align:start position:0% +aside that it's difficult to find this +number or in some cases this equivalent + + align:start position:0% +number or in some cases this equivalent + + + align:start position:0% +number or in some cases this equivalent +number um you know we have a means of + + align:start position:0% +number um you know we have a means of + + + align:start position:0% +number um you know we have a means of +predicting what it is and I can just + + align:start position:0% +predicting what it is and I can just + + + align:start position:0% +predicting what it is and I can just +model that heat transfer as a thermal + + align:start position:0% +model that heat transfer as a thermal + + + align:start position:0% +model that heat transfer as a thermal +resistor again okay any questions about + + align:start position:0% + + + + align:start position:0% + +that so how might we use this + + align:start position:0% +that so how might we use this + + + align:start position:0% +that so how might we use this +okay well in the typical + + align:start position:0% +okay well in the typical + + + align:start position:0% +okay well in the typical +case right um I'm going to dissipate + + align:start position:0% +case right um I'm going to dissipate + + + align:start position:0% +case right um I'm going to dissipate +some power in my + + align:start position:0% +some power in my + + + align:start position:0% +some power in my +device I've got to connect that device + + align:start position:0% +device I've got to connect that device + + + align:start position:0% +device I've got to connect that device +through some heat transfer means and the + + align:start position:0% +through some heat transfer means and the + + + align:start position:0% +through some heat transfer means and the +heat transfer is going to carry it away + + align:start position:0% +heat transfer is going to carry it away + + + align:start position:0% +heat transfer is going to carry it away +okay so here's a typical + + align:start position:0% +okay so here's a typical + + + align:start position:0% +okay so here's a typical +structure um you know maybe I have some + + align:start position:0% +structure um you know maybe I have some + + + align:start position:0% +structure um you know maybe I have some +power device this could be a mosfet okay + + align:start position:0% +power device this could be a mosfet okay + + + align:start position:0% +power device this could be a mosfet okay +and basically somewhere inside this + + align:start position:0% +and basically somewhere inside this + + + align:start position:0% +and basically somewhere inside this +device I'm dissipating a bunch of power + + align:start position:0% +device I'm dissipating a bunch of power + + + align:start position:0% +device I'm dissipating a bunch of power +right so that's a source of heat okay + + align:start position:0% +right so that's a source of heat okay + + + align:start position:0% +right so that's a source of heat okay +and then what I'm going to do is I'm + + align:start position:0% +and then what I'm going to do is I'm + + + align:start position:0% +and then what I'm going to do is I'm +going to say okay I need to connect that + + align:start position:0% +going to say okay I need to connect that + + + align:start position:0% +going to say okay I need to connect that +um down onto a heat sink and here when I + + align:start position:0% +um down onto a heat sink and here when I + + + align:start position:0% +um down onto a heat sink and here when I +connect this device I'm going to have + + align:start position:0% +connect this device I'm going to have + + + align:start position:0% +connect this device I'm going to have +some thermal I'm going to have some + + align:start position:0% +some thermal I'm going to have some + + + align:start position:0% +some thermal I'm going to have some +interface here okay what is that + + align:start position:0% +interface here okay what is that + + + align:start position:0% +interface here okay what is that +interface um I'll talk about that in a + + align:start position:0% +interface um I'll talk about that in a + + + align:start position:0% +interface um I'll talk about that in a +second but that's going to be between + + align:start position:0% +second but that's going to be between + + + align:start position:0% +second but that's going to be between +the device and then maybe a heat sink + + align:start position:0% +the device and then maybe a heat sink + + + align:start position:0% +the device and then maybe a heat sink +okay and maybe this seat sink has a + + align:start position:0% +okay and maybe this seat sink has a + + + align:start position:0% +okay and maybe this seat sink has a +bunch of fins that's help designed to + + align:start position:0% +bunch of fins that's help designed to + + + align:start position:0% +bunch of fins that's help designed to +help me cool this thing and so the + + align:start position:0% +help me cool this thing and so the + + + align:start position:0% +help me cool this thing and so the +Heat's going to come from the device + + align:start position:0% +Heat's going to come from the device + + + align:start position:0% +Heat's going to come from the device +through this interface into the heat + + align:start position:0% +through this interface into the heat + + + align:start position:0% +through this interface into the heat +sink and then maybe the heat sink's + + align:start position:0% +sink and then maybe the heat sink's + + + align:start position:0% +sink and then maybe the heat sink's +transferring it off to uh you know by + + align:start position:0% +transferring it off to uh you know by + + + align:start position:0% +transferring it off to uh you know by +convection past the heat SN out into + + align:start position:0% +convection past the heat SN out into + + + align:start position:0% +convection past the heat SN out into +space around it and and then I forget + + align:start position:0% +space around it and and then I forget + + + align:start position:0% +space around it and and then I forget +about the heat right it's just going out + + align:start position:0% +about the heat right it's just going out + + + align:start position:0% +about the heat right it's just going out +somewhere okay well what is this + + align:start position:0% +somewhere okay well what is this + + + align:start position:0% +somewhere okay well what is this +interface this device here and let me + + align:start position:0% +interface this device here and let me + + + align:start position:0% +interface this device here and let me +just + + align:start position:0% +just + + + align:start position:0% +just +illustrate um you know just as an + + align:start position:0% + + + + align:start position:0% + +example here is a typical + + align:start position:0% +example here is a typical + + + align:start position:0% +example here is a typical +mosfet okay this is in a to220 package + + align:start position:0% +mosfet okay this is in a to220 package + + + align:start position:0% +mosfet okay this is in a to220 package +which is you know maybe the not the most + + align:start position:0% +which is you know maybe the not the most + + + align:start position:0% +which is you know maybe the not the most +modern of packages but they're still + + align:start position:0% +modern of packages but they're still + + + align:start position:0% +modern of packages but they're still +used in a lot of cases and so the device + + align:start position:0% +used in a lot of cases and so the device + + + align:start position:0% +used in a lot of cases and so the device +is inside this plastic package these + + align:start position:0% +is inside this plastic package these + + + align:start position:0% +is inside this plastic package these +leads gate drain and Source are + + align:start position:0% +leads gate drain and Source are + + + align:start position:0% +leads gate drain and Source are +connected to the device and then one + + align:start position:0% +connected to the device and then one + + + align:start position:0% +connected to the device and then one +side of the device is connected down + + align:start position:0% +side of the device is connected down + + + align:start position:0% +side of the device is connected down +onto this pad through which you're going + + align:start position:0% +onto this pad through which you're going + + + align:start position:0% +onto this pad through which you're going +to transfer heat all right so that's + + align:start position:0% +to transfer heat all right so that's + + + align:start position:0% +to transfer heat all right so that's +sort of the case of the device so inside + + align:start position:0% +sort of the case of the device so inside + + + align:start position:0% +sort of the case of the device so inside +this package somewhere I'm dissipating + + align:start position:0% +this package somewhere I'm dissipating + + + align:start position:0% +this package somewhere I'm dissipating +heat and it goes to the case of the + + align:start position:0% +heat and it goes to the case of the + + + align:start position:0% +heat and it goes to the case of the +device then I'm going to mount that case + + align:start position:0% +device then I'm going to mount that case + + + align:start position:0% +device then I'm going to mount that case +of the device down to some heat sink + + align:start position:0% +of the device down to some heat sink + + + align:start position:0% +of the device down to some heat sink +okay but there is + + align:start position:0% +okay but there is + + + align:start position:0% +okay but there is +some interface to the heat sink now in a + + align:start position:0% +some interface to the heat sink now in a + + + align:start position:0% +some interface to the heat sink now in a +practical device it depends on the + + align:start position:0% +practical device it depends on the + + + align:start position:0% +practical device it depends on the +device type in this particular device + + align:start position:0% +device type in this particular device + + + align:start position:0% +device type in this particular device +this is a power mosfet that heat sink + + align:start position:0% +this is a power mosfet that heat sink + + + align:start position:0% +this is a power mosfet that heat sink +that terminal the device through which + + align:start position:0% +that terminal the device through which + + + align:start position:0% +that terminal the device through which +all the Heat's going to go is actually + + align:start position:0% +all the Heat's going to go is actually + + + align:start position:0% +all the Heat's going to go is actually +connected to the drain of the device to + + align:start position:0% +connected to the drain of the device to + + + align:start position:0% +connected to the drain of the device to +the to the high side the top side of the + + align:start position:0% +the to the high side the top side of the + + + align:start position:0% +the to the high side the top side of the +mosfet why because it's a vertical + + align:start position:0% +mosfet why because it's a vertical + + + align:start position:0% +mosfet why because it's a vertical +mosfet and that's the way they could + + align:start position:0% +mosfet and that's the way they could + + + align:start position:0% +mosfet and that's the way they could +connect it okay and so you know if that + + align:start position:0% +connect it okay and so you know if that + + + align:start position:0% +connect it okay and so you know if that +drain is say for a boost converter that + + align:start position:0% +drain is say for a boost converter that + + + align:start position:0% +drain is say for a boost converter that +may be flapping up and down in voltage + + align:start position:0% +may be flapping up and down in voltage + + + align:start position:0% +may be flapping up and down in voltage +so it's kind of unfortunate that you're + + align:start position:0% +so it's kind of unfortunate that you're + + + align:start position:0% +so it's kind of unfortunate that you're +trying to transfer heat out of something + + align:start position:0% +trying to transfer heat out of something + + + align:start position:0% +trying to transfer heat out of something +that's flying around in voltage right so + + align:start position:0% +that's flying around in voltage right so + + + align:start position:0% +that's flying around in voltage right so +in that + + align:start position:0% +in that + + + align:start position:0% +in that +case this thing might be a silicone + + align:start position:0% +case this thing might be a silicone + + + align:start position:0% +case this thing might be a silicone +insulation + + align:start position:0% + + + + align:start position:0% + +pad okay what does that thing do it's + + align:start position:0% +pad okay what does that thing do it's + + + align:start position:0% +pad okay what does that thing do it's +essentially it's electrically insulating + + align:start position:0% +essentially it's electrically insulating + + + align:start position:0% +essentially it's electrically insulating +but reasonably thermally conductive so + + align:start position:0% +but reasonably thermally conductive so + + + align:start position:0% +but reasonably thermally conductive so +it lets heat transfer through but not + + align:start position:0% +it lets heat transfer through but not + + + align:start position:0% +it lets heat transfer through but not +electrons and by the way that's not a + + align:start position:0% +electrons and by the way that's not a + + + align:start position:0% +electrons and by the way that's not a +very common thing right most things that + + align:start position:0% +very common thing right most things that + + + align:start position:0% +very common thing right most things that +are good thermal conductors are also + + align:start position:0% +are good thermal conductors are also + + + align:start position:0% +are good thermal conductors are also +good electrical conductors but you can + + align:start position:0% +good electrical conductors but you can + + + align:start position:0% +good electrical conductors but you can +find some materials that'll help you out + + align:start position:0% +find some materials that'll help you out + + + align:start position:0% +find some materials that'll help you out +there right so this thing might be um + + align:start position:0% +there right so this thing might be um + + + align:start position:0% +there right so this thing might be um +some electrical insulation pad to let + + align:start position:0% +some electrical insulation pad to let + + + align:start position:0% +some electrical insulation pad to let +you connect this thing to a heat sink + + align:start position:0% +you connect this thing to a heat sink + + + align:start position:0% +you connect this thing to a heat sink +thermally but not + + align:start position:0% +thermally but not + + + align:start position:0% +thermally but not +electrically okay uh you can find you + + align:start position:0% +electrically okay uh you can find you + + + align:start position:0% +electrically okay uh you can find you +know a typical brand name for this is + + align:start position:0% +know a typical brand name for this is + + + align:start position:0% +know a typical brand name for this is +like a s + + align:start position:0% +like a s + + + align:start position:0% +like a s +pad that's + + align:start position:0% +pad that's + + + align:start position:0% +pad that's +Bergquist trade name for it there's a + + align:start position:0% +Bergquist trade name for it there's a + + + align:start position:0% +Bergquist trade name for it there's a +lot of companies that make it and they + + align:start position:0% +lot of companies that make it and they + + + align:start position:0% +lot of companies that make it and they +come in varing degrees of quality and + + align:start position:0% +come in varing degrees of quality and + + + align:start position:0% +come in varing degrees of quality and +electrical insulation capability and so + + align:start position:0% +electrical insulation capability and so + + + align:start position:0% +electrical insulation capability and so +forth okay in some applications maybe + + align:start position:0% +forth okay in some applications maybe + + + align:start position:0% +forth okay in some applications maybe +you don't + + align:start position:0% +you don't + + + align:start position:0% +you don't +need electrical insulation right if you + + align:start position:0% +need electrical insulation right if you + + + align:start position:0% +need electrical insulation right if you +happen to have a pack pack AG that was + + align:start position:0% +happen to have a pack pack AG that was + + + align:start position:0% +happen to have a pack pack AG that was +already electrically insulated and they + + align:start position:0% +already electrically insulated and they + + + align:start position:0% +already electrically insulated and they +do make some fets that way or the + + align:start position:0% +do make some fets that way or the + + + align:start position:0% +do make some fets that way or the +package happened to be connected to + + align:start position:0% +package happened to be connected to + + + align:start position:0% +package happened to be connected to +ground maybe you could connect that + + align:start position:0% +ground maybe you could connect that + + + align:start position:0% +ground maybe you could connect that +directly down to the heat sink okay but + + align:start position:0% +directly down to the heat sink okay but + + + align:start position:0% +directly down to the heat sink okay but +often you will have some other interface + + align:start position:0% +often you will have some other interface + + + align:start position:0% +often you will have some other interface +between your device and your heat sink + + align:start position:0% +between your device and your heat sink + + + align:start position:0% +between your device and your heat sink +why because you know if you think about + + align:start position:0% +why because you know if you think about + + + align:start position:0% +why because you know if you think about +surface roughness you know maybe here's + + align:start position:0% +surface roughness you know maybe here's + + + align:start position:0% +surface roughness you know maybe here's +the back package of the device and + + align:start position:0% +the back package of the device and + + + align:start position:0% +the back package of the device and +here's the surface of the heat sink you + + align:start position:0% +here's the surface of the heat sink you + + + align:start position:0% +here's the surface of the heat sink you +know you don't want any air in between + + align:start position:0% +know you don't want any air in between + + + align:start position:0% +know you don't want any air in between +it so in that case what you might do is + + align:start position:0% +it so in that case what you might do is + + + align:start position:0% +it so in that case what you might do is +use thermal grease so this could also be + + align:start position:0% +use thermal grease so this could also be + + + align:start position:0% +use thermal grease so this could also be +uh in instead thermal + + align:start position:0% + + + + align:start position:0% + +grease okay why would I use thermal + + align:start position:0% +grease okay why would I use thermal + + + align:start position:0% +grease okay why would I use thermal +grease because thermal grease has a lot + + align:start position:0% +grease because thermal grease has a lot + + + align:start position:0% +grease because thermal grease has a lot +better heat transfer characteristics + + align:start position:0% +better heat transfer characteristics + + + align:start position:0% +better heat transfer characteristics +than air does so you wouldn't want any + + align:start position:0% +than air does so you wouldn't want any + + + align:start position:0% +than air does so you wouldn't want any +scratches or open areas in the back of + + align:start position:0% +scratches or open areas in the back of + + + align:start position:0% +scratches or open areas in the back of +your device kind of limiting heat flow + + align:start position:0% +your device kind of limiting heat flow + + + align:start position:0% +your device kind of limiting heat flow +so you fill that with thermal grease of + + align:start position:0% +so you fill that with thermal grease of + + + align:start position:0% +so you fill that with thermal grease of +course thermal grease has way worse + + align:start position:0% +course thermal grease has way worse + + + align:start position:0% +course thermal grease has way worse +thermal con conductivity than metal so + + align:start position:0% +thermal con conductivity than metal so + + + align:start position:0% +thermal con conductivity than metal so +what you would do is you just put enough + + align:start position:0% +what you would do is you just put enough + + + align:start position:0% +what you would do is you just put enough +thermal grease on it and you sometimes + + align:start position:0% +thermal grease on it and you sometimes + + + align:start position:0% +thermal grease on it and you sometimes +if you've ever mounted say a CPU down to + + align:start position:0% +if you've ever mounted say a CPU down to + + + align:start position:0% +if you've ever mounted say a CPU down to +the CPU Cooler they'll give you this + + align:start position:0% +the CPU Cooler they'll give you this + + + align:start position:0% +the CPU Cooler they'll give you this +material to put in there and the idea is + + align:start position:0% +material to put in there and the idea is + + + align:start position:0% +material to put in there and the idea is +you put it on and then you basically try + + align:start position:0% +you put it on and then you basically try + + + align:start position:0% +you put it on and then you basically try +to squeegee it all off it's just to fill + + align:start position:0% +to squeegee it all off it's just to fill + + + align:start position:0% +to squeegee it all off it's just to fill +in cracks you don't want like a thick + + align:start position:0% +in cracks you don't want like a thick + + + align:start position:0% +in cracks you don't want like a thick +layer of this stuff because it will add + + align:start position:0% +layer of this stuff because it will add + + + align:start position:0% +layer of this stuff because it will add +thermal resistance to this path the sil + + align:start position:0% +thermal resistance to this path the sil + + + align:start position:0% +thermal resistance to this path the sil +pad has thermal resistance so does + + align:start position:0% +pad has thermal resistance so does + + + align:start position:0% +pad has thermal resistance so does +thermal grease so you put as little as + + align:start position:0% +thermal grease so you put as little as + + + align:start position:0% +thermal grease so you put as little as +on as you can get away with it just to + + align:start position:0% +on as you can get away with it just to + + + align:start position:0% +on as you can get away with it just to +make it essentially flat and then Mount + + align:start position:0% +make it essentially flat and then Mount + + + align:start position:0% +make it essentially flat and then Mount +that device down to the heat + + align:start position:0% +that device down to the heat + + + align:start position:0% +that device down to the heat +sink any questions about that so it + + align:start position:0% +sink any questions about that so it + + + align:start position:0% +sink any questions about that so it +depends whether you need electrical + + align:start position:0% +depends whether you need electrical + + + align:start position:0% +depends whether you need electrical +insulation whether you just use thermal + + align:start position:0% +insulation whether you just use thermal + + + align:start position:0% +insulation whether you just use thermal +grease or you use an insulating pad or + + align:start position:0% +grease or you use an insulating pad or + + + align:start position:0% +grease or you use an insulating pad or +you use some kind of non-insulated + + align:start position:0% +you use some kind of non-insulated + + + align:start position:0% +you use some kind of non-insulated +thermal pad that'll you know kind of be + + align:start position:0% +thermal pad that'll you know kind of be + + + align:start position:0% +thermal pad that'll you know kind of be +compliant + + align:start position:0% +compliant + + + align:start position:0% +compliant +okay and that's the physical structure + + align:start position:0% +okay and that's the physical structure + + + align:start position:0% +okay and that's the physical structure +what does this thing look like as a + + align:start position:0% +what does this thing look like as a + + + align:start position:0% +what does this thing look like as a +circuit + + align:start position:0% +circuit + + + align:start position:0% +circuit +model well + + align:start position:0% +model well + + + align:start position:0% +model well +here um + + align:start position:0% +here um + + + align:start position:0% +here um +I will have some P + + align:start position:0% +I will have some P + + + align:start position:0% +I will have some P +disc that's the power I'm dissipating in + + align:start position:0% +disc that's the power I'm dissipating in + + + align:start position:0% +disc that's the power I'm dissipating in +the device right and ideally that power + + align:start position:0% +the device right and ideally that power + + + align:start position:0% +the device right and ideally that power +dissipation is connected to absolute + + align:start position:0% +dissipation is connected to absolute + + + align:start position:0% +dissipation is connected to absolute +zero but maybe I'll just call this T + + align:start position:0% +zero but maybe I'll just call this T + + + align:start position:0% +zero but maybe I'll just call this T +ambient and recognize that + + align:start position:0% + + + + align:start position:0% + +oh maybe this is connected to really Z + + align:start position:0% +oh maybe this is connected to really Z + + + align:start position:0% +oh maybe this is connected to really Z +Kelvin okay so I can either treat this + + align:start position:0% +Kelvin okay so I can either treat this + + + align:start position:0% +Kelvin okay so I can either treat this +as zero Kelvin or call it you know + + align:start position:0% +as zero Kelvin or call it you know + + + align:start position:0% +as zero Kelvin or call it you know +whatever my ambient temperature is and + + align:start position:0% +whatever my ambient temperature is and + + + align:start position:0% +whatever my ambient temperature is and +work from there + + align:start position:0% +work from there + + + align:start position:0% +work from there +okay that's the power dissipation and we + + align:start position:0% +okay that's the power dissipation and we + + + align:start position:0% +okay that's the power dissipation and we +often say this temperature is at T + + align:start position:0% +often say this temperature is at T + + + align:start position:0% +often say this temperature is at T +Junction right from so it's either you + + align:start position:0% +Junction right from so it's either you + + + align:start position:0% +Junction right from so it's either you +know this is T Junction to ambient or t + + align:start position:0% +know this is T Junction to ambient or t + + + align:start position:0% +know this is T Junction to ambient or t +Junction absolute depending upon how I + + align:start position:0% +Junction absolute depending upon how I + + + align:start position:0% +Junction absolute depending upon how I +decide to write this The Junction is + + align:start position:0% +decide to write this The Junction is + + + align:start position:0% +decide to write this The Junction is +just my notion of wherever the power is + + align:start position:0% +just my notion of wherever the power is + + + align:start position:0% +just my notion of wherever the power is +being dissipated in the device it may be + + align:start position:0% +being dissipated in the device it may be + + + align:start position:0% +being dissipated in the device it may be +an actual physical semiconductor + + align:start position:0% +an actual physical semiconductor + + + align:start position:0% +an actual physical semiconductor +Junction it may just be you know + + align:start position:0% +Junction it may just be you know + + + align:start position:0% +Junction it may just be you know +wherever in this device is where the + + align:start position:0% +wherever in this device is where the + + + align:start position:0% +wherever in this device is where the +Heat's being + + align:start position:0% +Heat's being + + + align:start position:0% +Heat's being +dissipated + + align:start position:0% +dissipated + + + align:start position:0% +dissipated +okay then I've got to + + align:start position:0% +okay then I've got to + + + align:start position:0% +okay then I've got to +transfer the heat to the surface of the + + align:start position:0% +transfer the heat to the surface of the + + + align:start position:0% +transfer the heat to the surface of the +device right because I said you know the + + align:start position:0% +device right because I said you know the + + + align:start position:0% +device right because I said you know the +Heat's + + align:start position:0% +Heat's + + + align:start position:0% +Heat's +actually uh being dissipated inside and + + align:start position:0% +actually uh being dissipated inside and + + + align:start position:0% +actually uh being dissipated inside and +there's some thermal resistance junct + + align:start position:0% +there's some thermal resistance junct + + + align:start position:0% +there's some thermal resistance junct +between where the Heat's being + + align:start position:0% +between where the Heat's being + + + align:start position:0% +between where the Heat's being +dissipated inside the semiconductor to + + align:start position:0% +dissipated inside the semiconductor to + + + align:start position:0% +dissipated inside the semiconductor to +the actual case so there's going to be + + align:start position:0% +the actual case so there's going to be + + + align:start position:0% +the actual case so there's going to be +some + + align:start position:0% +some + + + align:start position:0% +some +rth Jun + + align:start position:0% +rth Jun + + + align:start position:0% +rth Jun +to + + align:start position:0% +to + + + align:start position:0% +to +case + + align:start position:0% +case + + + align:start position:0% +case +right and then there's going to be some + + align:start position:0% +right and then there's going to be some + + + align:start position:0% +right and then there's going to be some +other thermal resistance and so this + + align:start position:0% +other thermal resistance and so this + + + align:start position:0% +other thermal resistance and so this +temperature here would be the T + + align:start position:0% +temperature here would be the T + + + align:start position:0% +temperature here would be the T +case right then there's going to be some + + align:start position:0% +case right then there's going to be some + + + align:start position:0% +case right then there's going to be some +other thermal + + align:start position:0% +other thermal + + + align:start position:0% +other thermal +resistance + + align:start position:0% +resistance + + + align:start position:0% +resistance +rth case to + + align:start position:0% +rth case to + + + align:start position:0% +rth case to +sync okay that depends upon is this + + align:start position:0% +sync okay that depends upon is this + + + align:start position:0% +sync okay that depends upon is this +grease is it a thermal pad you know what + + align:start position:0% +grease is it a thermal pad you know what + + + align:start position:0% +grease is it a thermal pad you know what +is it and that and I care because that's + + align:start position:0% +is it and that and I care because that's + + + align:start position:0% +is it and that and I care because that's +going to contribute to temperature rise + + align:start position:0% +going to contribute to temperature rise + + + align:start position:0% +going to contribute to temperature rise +and then I you know over here I have my + + align:start position:0% +and then I you know over here I have my + + + align:start position:0% +and then I you know over here I have my +heat sink right and that heat sink if I + + align:start position:0% +heat sink right and that heat sink if I + + + align:start position:0% +heat sink right and that heat sink if I +include what's going to transfer off it + + align:start position:0% +include what's going to transfer off it + + + align:start position:0% +include what's going to transfer off it +by conduction and convection right maybe + + align:start position:0% +by conduction and convection right maybe + + + align:start position:0% +by conduction and convection right maybe +I say there is + + align:start position:0% + + + + align:start position:0% + +some + + align:start position:0% +some + + + align:start position:0% +some +rth sync to ambient okay and I connect + + align:start position:0% +rth sync to ambient okay and I connect + + + align:start position:0% +rth sync to ambient okay and I connect +this back to ambient and that's my + + align:start position:0% +this back to ambient and that's my + + + align:start position:0% +this back to ambient and that's my +thermal model and this is T sync right + + align:start position:0% +thermal model and this is T sync right + + + align:start position:0% +thermal model and this is T sync right +so this is my model for the whole thing + + align:start position:0% +so this is my model for the whole thing + + + align:start position:0% +so this is my model for the whole thing +any questions about that and I should + + align:start position:0% +any questions about that and I should + + + align:start position:0% +any questions about that and I should +say this is in thermal steady + + align:start position:0% +say this is in thermal steady + + + align:start position:0% +say this is in thermal steady +state now um fortunately if you get a + + align:start position:0% +state now um fortunately if you get a + + + align:start position:0% +state now um fortunately if you get a +lot of typical devices and you look + + align:start position:0% +lot of typical devices and you look + + + align:start position:0% +lot of typical devices and you look +carefully in the device data sheet here + + align:start position:0% +carefully in the device data sheet here + + + align:start position:0% +carefully in the device data sheet here +we go what they tell me is they've done + + align:start position:0% +we go what they tell me is they've done + + + align:start position:0% +we go what they tell me is they've done +some measurements somebody with a lot of + + align:start position:0% +some measurements somebody with a lot of + + + align:start position:0% +some measurements somebody with a lot of +thermal modeling experiences said done + + align:start position:0% +thermal modeling experiences said done + + + align:start position:0% +thermal modeling experiences said done +some measurements to figure out how hot + + align:start position:0% +some measurements to figure out how hot + + + align:start position:0% +some measurements to figure out how hot +the Junctions are going to get from + + align:start position:0% +the Junctions are going to get from + + + align:start position:0% +the Junctions are going to get from +above the C for a given amount of + + align:start position:0% +above the C for a given amount of + + + align:start position:0% +above the C for a given amount of +dissipation and they give me a thermal + + align:start position:0% +dissipation and they give me a thermal + + + align:start position:0% +dissipation and they give me a thermal +resistance Junction to case and they say + + align:start position:0% +resistance Junction to case and they say + + + align:start position:0% +resistance Junction to case and they say +here it's 2.5 de watt then they tell me + + align:start position:0% +here it's 2.5 de watt then they tell me + + + align:start position:0% +here it's 2.5 de watt then they tell me +oh if you go get you know just the right + + align:start position:0% +oh if you go get you know just the right + + + align:start position:0% +oh if you go get you know just the right +amount of thermal grease you do a really + + align:start position:0% +amount of thermal grease you do a really + + + align:start position:0% +amount of thermal grease you do a really +good job of mounting this down to a heat + + align:start position:0% +good job of mounting this down to a heat + + + align:start position:0% +good job of mounting this down to a heat +sink so we're we're not worrying about + + align:start position:0% +sink so we're we're not worrying about + + + align:start position:0% +sink so we're we're not worrying about +any additional insulation pad here it's + + align:start position:0% +any additional insulation pad here it's + + + align:start position:0% +any additional insulation pad here it's +another half a degree C watt between the + + align:start position:0% +another half a degree C watt between the + + + align:start position:0% +another half a degree C watt between the +case and the sink that's if I don't need + + align:start position:0% +case and the sink that's if I don't need + + + align:start position:0% +case and the sink that's if I don't need +electrical isolation if I do I have to + + align:start position:0% +electrical isolation if I do I have to + + + align:start position:0% +electrical isolation if I do I have to +look up the thermal resistance of my S + + align:start position:0% +look up the thermal resistance of my S + + + align:start position:0% +look up the thermal resistance of my S +pad or whatever else I'm putting in + + align:start position:0% +pad or whatever else I'm putting in + + + align:start position:0% +pad or whatever else I'm putting in +there + + align:start position:0% +there + + + align:start position:0% +there +and then then I'm you know usually as + + align:start position:0% +and then then I'm you know usually as + + + align:start position:0% +and then then I'm you know usually as +the designer I'm trying to pick this + + align:start position:0% +the designer I'm trying to pick this + + + align:start position:0% +the designer I'm trying to pick this +right but if I went out and picked a + + align:start position:0% +right but if I went out and picked a + + + align:start position:0% +right but if I went out and picked a +particular heat sync I can look up its + + align:start position:0% +particular heat sync I can look up its + + + align:start position:0% +particular heat sync I can look up its +value of rth sync to ambient right so + + align:start position:0% +value of rth sync to ambient right so + + + align:start position:0% +value of rth sync to ambient right so +then I can find um sort of delt T + + align:start position:0% +then I can find um sort of delt T + + + align:start position:0% +then I can find um sort of delt T +Junction to ambient is simply going to + + align:start position:0% +Junction to ambient is simply going to + + + align:start position:0% +Junction to ambient is simply going to +be p + + align:start position:0% +be p + + + align:start position:0% +be p +dis which is this power dissipation + + align:start position:0% +dis which is this power dissipation + + + align:start position:0% +dis which is this power dissipation +times + + align:start position:0% + + + + align:start position:0% + +rth Junction to case plus + + align:start position:0% +rth Junction to case plus + + + align:start position:0% +rth Junction to case plus +rth case to sync plus rth sync to + + align:start position:0% +rth case to sync plus rth sync to + + + align:start position:0% +rth case to sync plus rth sync to +ambient right and then I'm done if in my + + align:start position:0% +ambient right and then I'm done if in my + + + align:start position:0% +ambient right and then I'm done if in my +example you know a typical example uh + + align:start position:0% +example you know a typical example uh + + + align:start position:0% +example you know a typical example uh +numbers that I might use um I said t + + align:start position:0% + + + + align:start position:0% + +ambient T ambient might be + + align:start position:0% +ambient T ambient might be + + + align:start position:0% +ambient T ambient might be +40° C I don't know that's not that's a + + align:start position:0% +40° C I don't know that's not that's a + + + align:start position:0% +40° C I don't know that's not that's a +very that's actually a pretty cool + + align:start position:0% +very that's actually a pretty cool + + + align:start position:0% +very that's actually a pretty cool +ambient temperature you know some + + align:start position:0% +ambient temperature you know some + + + align:start position:0% +ambient temperature you know some +industrial stuff you design they assume + + align:start position:0% +industrial stuff you design they assume + + + align:start position:0% +industrial stuff you design they assume +the ambient is going to be 100° C but + + align:start position:0% +the ambient is going to be 100° C but + + + align:start position:0% +the ambient is going to be 100° C but +you know 40° C is hot but not crazy hot + + align:start position:0% +you know 40° C is hot but not crazy hot + + + align:start position:0% +you know 40° C is hot but not crazy hot +if you're in in a room right um and + + align:start position:0% +if you're in in a room right um and + + + align:start position:0% +if you're in in a room right um and +maybe I would say this kind of device uh + + align:start position:0% +maybe I would say this kind of device uh + + + align:start position:0% +maybe I would say this kind of device uh +P disc might be equal to 10 watts right + + align:start position:0% +P disc might be equal to 10 watts right + + + align:start position:0% +P disc might be equal to 10 watts right +this is something I got from my circuit + + align:start position:0% +this is something I got from my circuit + + + align:start position:0% +this is something I got from my circuit +design right so here I could say okay + + align:start position:0% +design right so here I could say okay + + + align:start position:0% +design right so here I could say okay +that's 10 watts times Junction to case I + + align:start position:0% +that's 10 watts times Junction to case I + + + align:start position:0% +that's 10 watts times Junction to case I +said was 2.5 de C per + + align:start position:0% +said was 2.5 de C per + + + align:start position:0% +said was 2.5 de C per +watt right plus 0.5 degrees C per + + align:start position:0% +watt right plus 0.5 degrees C per + + + align:start position:0% +watt right plus 0.5 degrees C per +watt was the if I just had thermal + + align:start position:0% +watt was the if I just had thermal + + + align:start position:0% +watt was the if I just had thermal +degrees in there and I went out and I + + align:start position:0% +degrees in there and I went out and I + + + align:start position:0% +degrees in there and I went out and I +bought a red Point thermoid km 51 heat + + align:start position:0% +bought a red Point thermoid km 51 heat + + + align:start position:0% +bought a red Point thermoid km 51 heat +sink that's just one of these convection + + align:start position:0% +sink that's just one of these convection + + + align:start position:0% +sink that's just one of these convection +cooled heat sinks to which I might Mount + + align:start position:0% +cooled heat sinks to which I might Mount + + + align:start position:0% +cooled heat sinks to which I might Mount +this device uh that is 4.8 degrees C per + + align:start position:0% +this device uh that is 4.8 degrees C per + + + align:start position:0% +this device uh that is 4.8 degrees C per +watt + + align:start position:0% + + + + align:start position:0% + +right which if I say this is plus T + + align:start position:0% +right which if I say this is plus T + + + align:start position:0% +right which if I say this is plus T +ambient this would be just T Junction + + align:start position:0% +ambient this would be just T Junction + + + align:start position:0% +ambient this would be just T Junction +would be T ambient plus this stuff + + align:start position:0% +would be T ambient plus this stuff + + + align:start position:0% +would be T ambient plus this stuff +right this would give me 118 degre + + align:start position:0% +right this would give me 118 degre + + + align:start position:0% +right this would give me 118 degre +C and maybe I'd be a happy guy right + + align:start position:0% +C and maybe I'd be a happy guy right + + + align:start position:0% +C and maybe I'd be a happy guy right +typical devices that you can buy in + + align:start position:0% +typical devices that you can buy in + + + align:start position:0% +typical devices that you can buy in +plastic + + align:start position:0% +plastic + + + align:start position:0% +plastic +packages 150 to 175 is a maximum + + align:start position:0% +packages 150 to 175 is a maximum + + + align:start position:0% +packages 150 to 175 is a maximum +temperature you're allowed to get the + + align:start position:0% +temperature you're allowed to get the + + + align:start position:0% +temperature you're allowed to get the +junction um + + align:start position:0% +junction um + + + align:start position:0% +junction um +you can get devices that are specially + + align:start position:0% +you can get devices that are specially + + + align:start position:0% +you can get devices that are specially +packaged that'll go higher or if they're + + align:start position:0% +packaged that'll go higher or if they're + + + align:start position:0% +packaged that'll go higher or if they're +they're not going to you know bad stuff + + align:start position:0% +they're not going to you know bad stuff + + + align:start position:0% +they're not going to you know bad stuff +won't happen to the device it's often + + align:start position:0% +won't happen to the device it's often + + + align:start position:0% +won't happen to the device it's often +limited by the packaging but typically + + align:start position:0% +limited by the packaging but typically + + + align:start position:0% +limited by the packaging but typically +150 or 175 is what you can get and this + + align:start position:0% +150 or 175 is what you can get and this + + + align:start position:0% +150 or 175 is what you can get and this +just gives me some + + align:start position:0% +just gives me some + + + align:start position:0% +just gives me some +margin any is that on the the data sheet + + align:start position:0% +margin any is that on the the data sheet + + + align:start position:0% +margin any is that on the the data sheet +uh yes usually a data sheet will tell + + align:start position:0% +uh yes usually a data sheet will tell + + + align:start position:0% +uh yes usually a data sheet will tell +you what the maximum allowable + + align:start position:0% +you what the maximum allowable + + + align:start position:0% +you what the maximum allowable +temperature here we go uh operating and + + align:start position:0% +temperature here we go uh operating and + + + align:start position:0% +temperature here we go uh operating and +storage temperature range uh operating + + align:start position:0% +storage temperature range uh operating + + + align:start position:0% +storage temperature range uh operating +Junction and storage temperature range + + align:start position:0% +Junction and storage temperature range + + + align:start position:0% +Junction and storage temperature range +150° C for this part okay a lot of more + + align:start position:0% +150° C for this part okay a lot of more + + + align:start position:0% +150° C for this part okay a lot of more +modern devices might be 175 okay it just + + align:start position:0% +modern devices might be 175 okay it just + + + align:start position:0% +modern devices might be 175 okay it just +depends what you're buying so what would + + align:start position:0% +depends what you're buying so what would + + + align:start position:0% +depends what you're buying so what would +you be a really job usually what you do + + align:start position:0% +you be a really job usually what you do + + + align:start position:0% +you be a really job usually what you do +is you know all this stuff you know your + + align:start position:0% +is you know all this stuff you know your + + + align:start position:0% +is you know all this stuff you know your +ambient of specification you know your + + align:start position:0% +ambient of specification you know your + + + align:start position:0% +ambient of specification you know your +dissipation because you calculated it + + align:start position:0% +dissipation because you calculated it + + + align:start position:0% +dissipation because you calculated it +you know these things and your job is to + + align:start position:0% +you know these things and your job is to + + + align:start position:0% +you know these things and your job is to +go pick the heat sink or maybe the + + align:start position:0% +go pick the heat sink or maybe the + + + align:start position:0% +go pick the heat sink or maybe the +thermal interface material and you have + + align:start position:0% +thermal interface material and you have + + + align:start position:0% +thermal interface material and you have +to pick this so that this number doesn't + + align:start position:0% +to pick this so that this number doesn't + + + align:start position:0% +to pick this so that this number doesn't +get too high right so I don't know this + + align:start position:0% +get too high right so I don't know this + + + align:start position:0% +get too high right so I don't know this +stuff in advance this is the thing I'm + + align:start position:0% +stuff in advance this is the thing I'm + + + align:start position:0% +stuff in advance this is the thing I'm +choosing as the heat snc designer okay + + align:start position:0% +choosing as the heat snc designer okay + + + align:start position:0% +choosing as the heat snc designer okay +what happens if you can't do it well you + + align:start position:0% +what happens if you can't do it well you + + + align:start position:0% +what happens if you can't do it well you +either got to go reduce your dissipation + + align:start position:0% +either got to go reduce your dissipation + + + align:start position:0% +either got to go reduce your dissipation +or find a better package with a lower + + align:start position:0% +or find a better package with a lower + + + align:start position:0% +or find a better package with a lower +Junction to case or some other + + align:start position:0% +Junction to case or some other + + + align:start position:0% +Junction to case or some other +combination of things right and you're + + align:start position:0% +combination of things right and you're + + + align:start position:0% +combination of things right and you're +often pushed up against the wall if + + align:start position:0% +often pushed up against the wall if + + + align:start position:0% +often pushed up against the wall if +especially if you're trying to go for + + align:start position:0% +especially if you're trying to go for + + + align:start position:0% +especially if you're trying to go for +high power + + align:start position:0% +high power + + + align:start position:0% +high power +density + + align:start position:0% +density + + + align:start position:0% +density +questions so it seems like a a lot to do + + align:start position:0% +questions so it seems like a a lot to do + + + align:start position:0% +questions so it seems like a a lot to do +for like one component in your your + + align:start position:0% +for like one component in your your + + + align:start position:0% +for like one component in your your +system what do you do for like a + + align:start position:0% +system what do you do for like a + + + align:start position:0% +system what do you do for like a +workflow and you have a lot of + + align:start position:0% +workflow and you have a lot of + + + align:start position:0% +workflow and you have a lot of +components in C so if you're a power + + align:start position:0% +components in C so if you're a power + + + align:start position:0% +components in C so if you're a power +converter designer right usually you + + align:start position:0% +converter designer right usually you + + + align:start position:0% +converter designer right usually you +only have a few sources of thermal + + align:start position:0% +only have a few sources of thermal + + + align:start position:0% +only have a few sources of thermal +dissipation that are the most important + + align:start position:0% +dissipation that are the most important + + + align:start position:0% +dissipation that are the most important +right and they're often your power + + align:start position:0% +right and they're often your power + + + align:start position:0% +right and they're often your power +devices at a broader scale right if + + align:start position:0% +devices at a broader scale right if + + + align:start position:0% +devices at a broader scale right if +you're if if you have to consider the + + align:start position:0% +you're if if you have to consider the + + + align:start position:0% +you're if if you have to consider the +whole thermal design well either you get + + align:start position:0% +whole thermal design well either you get + + + align:start position:0% +whole thermal design well either you get +a bigger Network or you start to pull + + align:start position:0% +a bigger Network or you start to pull + + + align:start position:0% +a bigger Network or you start to pull +out you know uh computation like finite + + align:start position:0% +out you know uh computation like finite + + + align:start position:0% +out you know uh computation like finite +element tools or something like that but + + align:start position:0% +element tools or something like that but + + + align:start position:0% +element tools or something like that but +very often for a power converter design + + align:start position:0% +very often for a power converter design + + + align:start position:0% +very often for a power converter design +you know you think you got your you know + + align:start position:0% +you know you think you got your you know + + + align:start position:0% +you know you think you got your you know +in a buck converter you might have your + + align:start position:0% +in a buck converter you might have your + + + align:start position:0% +in a buck converter you might have your +mosfet and your diode as being big + + align:start position:0% +mosfet and your diode as being big + + + align:start position:0% +mosfet and your diode as being big +sources of loss and then maybe your + + align:start position:0% +sources of loss and then maybe your + + + align:start position:0% +sources of loss and then maybe your +inductor is next right and you just + + align:start position:0% +inductor is next right and you just + + + align:start position:0% +inductor is next right and you just +model those into the system and and + + align:start position:0% +model those into the system and and + + + align:start position:0% +model those into the system and and +figure out how you're going to heat sync + + align:start position:0% +figure out how you're going to heat sync + + + align:start position:0% +figure out how you're going to heat sync +it I should say by the way that a very + + align:start position:0% +it I should say by the way that a very + + + align:start position:0% +it I should say by the way that a very +typical thing that you would + + align:start position:0% +typical thing that you would + + + align:start position:0% +typical thing that you would +do is um you know m a very typical thing + + align:start position:0% +do is um you know m a very typical thing + + + align:start position:0% +do is um you know m a very typical thing +to do is I'm showing you one picture + + align:start position:0% +to do is I'm showing you one picture + + + align:start position:0% +to do is I'm showing you one picture +here right but it may be true that you + + align:start position:0% +here right but it may be true that you + + + align:start position:0% +here right but it may be true that you +come up and you um + + align:start position:0% + + + + align:start position:0% + +you might do the following you might + + align:start position:0% +you might do the following you might + + + align:start position:0% +you might do the following you might +have a heat + + align:start position:0% + + + + align:start position:0% + +sink and then you know your diode and + + align:start position:0% +sink and then you know your diode and + + + align:start position:0% +sink and then you know your diode and +your mosfet are right next to each other + + align:start position:0% +your mosfet are right next to each other + + + align:start position:0% +your mosfet are right next to each other +and mounted to the same heat sink right + + align:start position:0% +and mounted to the same heat sink right + + + align:start position:0% +and mounted to the same heat sink right +so what would you do you'd say okay + + align:start position:0% +so what would you do you'd say okay + + + align:start position:0% +so what would you do you'd say okay +here's P + + align:start position:0% + + + + align:start position:0% + +fat and here's TJ + + align:start position:0% +fat and here's TJ + + + align:start position:0% +fat and here's TJ +fet right and that would be rth you'd + + align:start position:0% +fet right and that would be rth you'd + + + align:start position:0% +fet right and that would be rth you'd +have Junction to Case Case to s so maybe + + align:start position:0% +have Junction to Case Case to s so maybe + + + align:start position:0% +have Junction to Case Case to s so maybe +that would rth Junction to sync would be + + align:start position:0% +that would rth Junction to sync would be + + + align:start position:0% +that would rth Junction to sync would be +the total and you do the same thing for + + align:start position:0% +the total and you do the same thing for + + + align:start position:0% +the total and you do the same thing for +rth Junction to sync for your + + align:start position:0% + + + + align:start position:0% + +diode right and here's + + align:start position:0% +diode right and here's + + + align:start position:0% +diode right and here's +TJ + + align:start position:0% +TJ + + + align:start position:0% +TJ +diode right and then you go out and get + + align:start position:0% +diode right and then you go out and get + + + align:start position:0% +diode right and then you go out and get +one + + align:start position:0% +one + + + align:start position:0% +one +rth syn to + + align:start position:0% +rth syn to + + + align:start position:0% +rth syn to +ambient and you go calculate what the + + align:start position:0% +ambient and you go calculate what the + + + align:start position:0% +ambient and you go calculate what the +junction temperature of the diode is and + + align:start position:0% +junction temperature of the diode is and + + + align:start position:0% +junction temperature of the diode is and +what the junction temperature of the FED + + align:start position:0% +what the junction temperature of the FED + + + align:start position:0% +what the junction temperature of the FED +is and you'd have to pick these things + + align:start position:0% +is and you'd have to pick these things + + + align:start position:0% +is and you'd have to pick these things +low enough and you can expand out from + + align:start position:0% +low enough and you can expand out from + + + align:start position:0% +low enough and you can expand out from +there + + align:start position:0% + + + + align:start position:0% + +questions + + align:start position:0% +questions + + + align:start position:0% +questions +okay so + + align:start position:0% +okay so + + + align:start position:0% +okay so +that's one way to think about + + align:start position:0% +that's one way to think about + + + align:start position:0% +that's one way to think about +it + + align:start position:0% +it + + + align:start position:0% +it +um this is the steady state thermal + + align:start position:0% +um this is the steady state thermal + + + align:start position:0% +um this is the steady state thermal +model right this is I plug my converter + + align:start position:0% +model right this is I plug my converter + + + align:start position:0% +model right this is I plug my converter +in I let it run for a long time + + align:start position:0% +in I let it run for a long time + + + align:start position:0% +in I let it run for a long time +everything up to its maximum temperature + + align:start position:0% +everything up to its maximum temperature + + + align:start position:0% +everything up to its maximum temperature +and I find out if it blows up or not + + align:start position:0% +and I find out if it blows up or not + + + align:start position:0% +and I find out if it blows up or not +right did the thing get too hot when + + align:start position:0% +right did the thing get too hot when + + + align:start position:0% +right did the thing get too hot when +everything settled out right but this + + align:start position:0% +everything settled out right but this + + + align:start position:0% +everything settled out right but this +isn't really a transient thermal model + + align:start position:0% +isn't really a transient thermal model + + + align:start position:0% +isn't really a transient thermal model +right I mean if I put my you know if I + + align:start position:0% +right I mean if I put my you know if I + + + align:start position:0% +right I mean if I put my you know if I +put my teac kettle on and I turn on the + + align:start position:0% +put my teac kettle on and I turn on the + + + align:start position:0% +put my teac kettle on and I turn on the +power which is basically dumping heat + + align:start position:0% +power which is basically dumping heat + + + align:start position:0% +power which is basically dumping heat +into the water from my tea kettle it + + align:start position:0% +into the water from my tea kettle it + + + align:start position:0% +into the water from my tea kettle it +doesn't instantly get up to maximum + + align:start position:0% +doesn't instantly get up to maximum + + + align:start position:0% +doesn't instantly get up to maximum +temperature right eventually it'll get + + align:start position:0% +temperature right eventually it'll get + + + align:start position:0% +temperature right eventually it'll get +up to hopefully it's if if I have + + align:start position:0% +up to hopefully it's if if I have + + + align:start position:0% +up to hopefully it's if if I have +pouring enough heat in to get up to + + align:start position:0% +pouring enough heat in to get up to + + + align:start position:0% +pouring enough heat in to get up to +Boiling right but it doesn't do it + + align:start position:0% +Boiling right but it doesn't do it + + + align:start position:0% +Boiling right but it doesn't do it +instantly this model does not tell you + + align:start position:0% +instantly this model does not tell you + + + align:start position:0% +instantly this model does not tell you +at + + align:start position:0% +at + + + align:start position:0% +at +all about instantaneous Behavior or + + align:start position:0% +all about instantaneous Behavior or + + + align:start position:0% +all about instantaneous Behavior or +transient behavior and sometimes that's + + align:start position:0% +transient behavior and sometimes that's + + + align:start position:0% +transient behavior and sometimes that's +quite important right because um we + + align:start position:0% +quite important right because um we + + + align:start position:0% +quite important right because um we +sometimes don't even wait for things to + + align:start position:0% +sometimes don't even wait for things to + + + align:start position:0% +sometimes don't even wait for things to +get to steady state or we want to know + + align:start position:0% +get to steady state or we want to know + + + align:start position:0% +get to steady state or we want to know +how quickly is my Beast going to heat up + + align:start position:0% +how quickly is my Beast going to heat up + + + align:start position:0% +how quickly is my Beast going to heat up +well it turns out you can measure that + + align:start position:0% +well it turns out you can measure that + + + align:start position:0% +well it turns out you can measure that +as + + align:start position:0% +as + + + align:start position:0% +as +well or you can model that as well and + + align:start position:0% +well or you can model that as well and + + + align:start position:0% +well or you can model that as well and +what we do with it is to model things + + align:start position:0% +what we do with it is to model things + + + align:start position:0% +what we do with it is to model things +with a thermal capacity + + align:start position:0% + + + + align:start position:0% + +Ence which has Unis Jews per degree C or + + align:start position:0% +Ence which has Unis Jews per degree C or + + + align:start position:0% +Ence which has Unis Jews per degree C or +Jews per + + align:start position:0% +Jews per + + + align:start position:0% +Jews per +Kelvin okay how many jewels do I have to + + align:start position:0% +Kelvin okay how many jewels do I have to + + + align:start position:0% +Kelvin okay how many jewels do I have to +put into this structure to raise it 1 + + align:start position:0% +put into this structure to raise it 1 + + + align:start position:0% +put into this structure to raise it 1 +degree Kelvin just by heating up the + + align:start position:0% +degree Kelvin just by heating up the + + + align:start position:0% +degree Kelvin just by heating up the +mass of this thing right and so if I + + align:start position:0% +mass of this thing right and so if I + + + align:start position:0% +mass of this thing right and so if I +knew the heat capacitance for some + + align:start position:0% +knew the heat capacitance for some + + + align:start position:0% +knew the heat capacitance for some +material per volume or per Mass I can + + align:start position:0% +material per volume or per Mass I can + + + align:start position:0% +material per volume or per Mass I can +multiply that and get the the heat + + align:start position:0% +multiply that and get the the heat + + + align:start position:0% +multiply that and get the the heat +capacitor of the whole thing right so + + align:start position:0% +capacitor of the whole thing right so + + + align:start position:0% +capacitor of the whole thing right so +maybe what I would do is I would say + + align:start position:0% +maybe what I would do is I would say + + + align:start position:0% +maybe what I would do is I would say +Okay suppose I have some surface + + align:start position:0% +Okay suppose I have some surface + + + align:start position:0% +Okay suppose I have some surface +here which I know is going to be at some + + align:start position:0% +here which I know is going to be at some + + + align:start position:0% +here which I know is going to be at some +you know T ambient or t let me call this + + align:start position:0% + + + + align:start position:0% + +T2 I guess I did call it t ambient okay + + align:start position:0% +T2 I guess I did call it t ambient okay + + + align:start position:0% +T2 I guess I did call it t ambient okay +so suppose it's t ambient okay and here + + align:start position:0% +so suppose it's t ambient okay and here + + + align:start position:0% +so suppose it's t ambient okay and here +I have some block of + + align:start position:0% +I have some block of + + + align:start position:0% +I have some block of +material piece of element of my + + align:start position:0% +material piece of element of my + + + align:start position:0% +material piece of element of my +system and let me characterize this by + + align:start position:0% +system and let me characterize this by + + + align:start position:0% +system and let me characterize this by +its average temperature + + align:start position:0% +its average temperature + + + align:start position:0% +its average temperature +T1 and now I'm going to go pour heat + + align:start position:0% +T1 and now I'm going to go pour heat + + + align:start position:0% +T1 and now I'm going to go pour heat +into this thing Q right this is the + + align:start position:0% +into this thing Q right this is the + + + align:start position:0% +into this thing Q right this is the +power dissipation you know maybe it's at + + align:start position:0% +power dissipation you know maybe it's at + + + align:start position:0% +power dissipation you know maybe it's at +this surface this is going in and + + align:start position:0% +this surface this is going in and + + + align:start position:0% +this surface this is going in and +heating this thing up and this thing is + + align:start position:0% +heating this thing up and this thing is + + + align:start position:0% +heating this thing up and this thing is +transferring energy to ground how would + + align:start position:0% +transferring energy to ground how would + + + align:start position:0% +transferring energy to ground how would +I model that well the the steady state + + align:start position:0% +I model that well the the steady state + + + align:start position:0% +I model that well the the steady state +model would be look like this right uh + + align:start position:0% +model would be look like this right uh + + + align:start position:0% +model would be look like this right uh +so this is p disc or this is Q I guess + + align:start position:0% +so this is p disc or this is Q I guess + + + align:start position:0% +so this is p disc or this is Q I guess +what did I call my note I guess I called + + align:start position:0% +what did I call my note I guess I called + + + align:start position:0% +what did I call my note I guess I called +it + + align:start position:0% +it + + + align:start position:0% +it +Q + + align:start position:0% +Q + + + align:start position:0% +Q +okay then I + + align:start position:0% + + + + align:start position:0% + +have some if this is T + + align:start position:0% + + + + align:start position:0% + +ambient right this is + + align:start position:0% +ambient right this is + + + align:start position:0% +ambient right this is +rth and this is T1 right so this is the + + align:start position:0% +rth and this is T1 right so this is the + + + align:start position:0% +rth and this is T1 right so this is the +thermal model in steady state for this + + align:start position:0% +thermal model in steady state for this + + + align:start position:0% +thermal model in steady state for this +thing okay how do I count for the fact + + align:start position:0% +thing okay how do I count for the fact + + + align:start position:0% +thing okay how do I count for the fact +that this thing has some thermal Mass it + + align:start position:0% +that this thing has some thermal Mass it + + + align:start position:0% +that this thing has some thermal Mass it +takes time to heat up well I find find + + align:start position:0% +takes time to heat up well I find find + + + align:start position:0% +takes time to heat up well I find find +out what his thermal capacitance is and + + align:start position:0% +out what his thermal capacitance is and + + + align:start position:0% +out what his thermal capacitance is and +I put it right + + align:start position:0% +I put it right + + + align:start position:0% +I put it right +here + + align:start position:0% +here + + + align:start position:0% +here +cth + + align:start position:0% +cth + + + align:start position:0% +cth +okay now this gives me a model so that + + align:start position:0% +okay now this gives me a model so that + + + align:start position:0% +okay now this gives me a model so that +if some at some time right suppose + + align:start position:0% +if some at some time right suppose + + + align:start position:0% +if some at some time right suppose +here's T right if I come in here and I + + align:start position:0% +here's T right if I come in here and I + + + align:start position:0% +here's T right if I come in here and I +say okay here is Q of + + align:start position:0% +say okay here is Q of + + + align:start position:0% +say okay here is Q of +T it's + + align:start position:0% +T it's + + + align:start position:0% +T it's +steps this is Q of T and at T equals z + + align:start position:0% +steps this is Q of T and at T equals z + + + align:start position:0% +steps this is Q of T and at T equals z +it turns on right what I'm going to get + + align:start position:0% +it turns on right what I'm going to get + + + align:start position:0% +it turns on right what I'm going to get +is a + + align:start position:0% +is a + + + align:start position:0% +is a +T1 with respect to + + align:start position:0% +T1 with respect to + + + align:start position:0% +T1 with respect to +ambient uh that's going to do + + align:start position:0% + + + + align:start position:0% + +this right it + + align:start position:0% +this right it + + + align:start position:0% +this right it +eventually I'm going to get you know the + + align:start position:0% +eventually I'm going to get you know the + + + align:start position:0% +eventually I'm going to get you know the +final value is going to be uh T1 minus t + + align:start position:0% +final value is going to be uh T1 minus t + + + align:start position:0% +final value is going to be uh T1 minus t +ambient is going to be equal to Q * + + align:start position:0% +ambient is going to be equal to Q * + + + align:start position:0% +ambient is going to be equal to Q * +rth that's its final value and it's + + align:start position:0% +rth that's its final value and it's + + + align:start position:0% +rth that's its final value and it's +going to rise with a time constant + + align:start position:0% +going to rise with a time constant + + + align:start position:0% +going to rise with a time constant +tow that's equal to RH + + align:start position:0% +tow that's equal to RH + + + align:start position:0% +tow that's equal to RH +TH or RH C rth + + align:start position:0% +TH or RH C rth + + + align:start position:0% +TH or RH C rth +cth okay so it you know it'll have a + + align:start position:0% +cth okay so it you know it'll have a + + + align:start position:0% +cth okay so it you know it'll have a +time constant it'll rise up so it won't + + align:start position:0% +time constant it'll rise up so it won't + + + align:start position:0% +time constant it'll rise up so it won't +immediately get hot it'll just rise over + + align:start position:0% +immediately get hot it'll just rise over + + + align:start position:0% +immediately get hot it'll just rise over +time okay now I should + + align:start position:0% +time okay now I should + + + align:start position:0% +time okay now I should +say + + align:start position:0% + + + + align:start position:0% + +fundamentally a thermal + + align:start position:0% +fundamentally a thermal + + + align:start position:0% +fundamentally a thermal +capacitance should technically always be + + align:start position:0% +capacitance should technically always be + + + align:start position:0% +capacitance should technically always be +referenced to absolute zero + + align:start position:0% +referenced to absolute zero + + + align:start position:0% +referenced to absolute zero +if I'm just dealing with some ambient + + align:start position:0% +if I'm just dealing with some ambient + + + align:start position:0% +if I'm just dealing with some ambient +and I want to call it an offset I can + + align:start position:0% +and I want to call it an offset I can + + + align:start position:0% +and I want to call it an offset I can +reference it to a fixed temperature but + + align:start position:0% +reference it to a fixed temperature but + + + align:start position:0% +reference it to a fixed temperature but +thermal capacitance is in terms of + + align:start position:0% +thermal capacitance is in terms of + + + align:start position:0% +thermal capacitance is in terms of +modeling them heating up I really have + + align:start position:0% +modeling them heating up I really have + + + align:start position:0% +modeling them heating up I really have +to in terms of modeling the physics I + + align:start position:0% +to in terms of modeling the physics I + + + align:start position:0% +to in terms of modeling the physics I +always have to have that thermal + + align:start position:0% +always have to have that thermal + + + align:start position:0% +always have to have that thermal +capacitance to my reference point which + + align:start position:0% +capacitance to my reference point which + + + align:start position:0% +capacitance to my reference point which +would ideally be 0 degrees + + align:start position:0% +would ideally be 0 degrees + + + align:start position:0% +would ideally be 0 degrees +Kelvin okay and I'll come back to that + + align:start position:0% +Kelvin okay and I'll come back to that + + + align:start position:0% +Kelvin okay and I'll come back to that +in a moment any questions about that + + align:start position:0% + + + + align:start position:0% + +though so in this case where we have + + align:start position:0% +though so in this case where we have + + + align:start position:0% +though so in this case where we have +multiple devices how would we insert the + + align:start position:0% +multiple devices how would we insert the + + + align:start position:0% +multiple devices how would we insert the +thermal capacitances that's right well + + align:start position:0% +thermal capacitances that's right well + + + align:start position:0% +thermal capacitances that's right well +so in this case + + align:start position:0% +so in this case + + + align:start position:0% +so in this case +right if I was talking and you got to + + align:start position:0% +right if I was talking and you got to + + + align:start position:0% +right if I was talking and you got to +say the thermal capacitance of what now + + align:start position:0% +say the thermal capacitance of what now + + + align:start position:0% +say the thermal capacitance of what now +the heat sink the device if I was + + align:start position:0% +the heat sink the device if I was + + + align:start position:0% +the heat sink the device if I was +talking about the thermal capacitance of + + align:start position:0% +talking about the thermal capacitance of + + + align:start position:0% +talking about the thermal capacitance of +the device I would put that right here + + align:start position:0% +the device I would put that right here + + + align:start position:0% +the device I would put that right here +right so this device package might have + + align:start position:0% +right so this device package might have + + + align:start position:0% +right so this device package might have +a thermal capacitance and this device + + align:start position:0% +a thermal capacitance and this device + + + align:start position:0% +a thermal capacitance and this device +might have a thermal capacitance and I + + align:start position:0% +might have a thermal capacitance and I + + + align:start position:0% +might have a thermal capacitance and I +ought to place it to to the reference + + align:start position:0% +ought to place it to to the reference + + + align:start position:0% +ought to place it to to the reference +potential the heat sink might have a + + align:start position:0% +potential the heat sink might have a + + + align:start position:0% +potential the heat sink might have a +thermal capacitance and then I get a + + align:start position:0% +thermal capacitance and then I get a + + + align:start position:0% +thermal capacitance and then I get a +higher order thing right now when I get + + align:start position:0% +higher order thing right now when I get + + + align:start position:0% +higher order thing right now when I get +to T equals infinity and I have some + + align:start position:0% +to T equals infinity and I have some + + + align:start position:0% +to T equals infinity and I have some +step response here it always settles out + + align:start position:0% +step response here it always settles out + + + align:start position:0% +step response here it always settles out +to the same steady state + + align:start position:0% +to the same steady state + + + align:start position:0% +to the same steady state +model + + align:start position:0% +model + + + align:start position:0% +model +OKAY along those + + align:start position:0% +OKAY along those + + + align:start position:0% +OKAY along those +lines what happens if I'm not too happy + + align:start position:0% +lines what happens if I'm not too happy + + + align:start position:0% +lines what happens if I'm not too happy +with the resolution I have here right + + align:start position:0% +with the resolution I have here right + + + align:start position:0% +with the resolution I have here right +I'm basically treating T1 of this whole + + align:start position:0% +I'm basically treating T1 of this whole + + + align:start position:0% +I'm basically treating T1 of this whole +block as being the same thing right but + + align:start position:0% +block as being the same thing right but + + + align:start position:0% +block as being the same thing right but +in reality I recognize you know if the + + align:start position:0% +in reality I recognize you know if the + + + align:start position:0% +in reality I recognize you know if the +Heat's really coming in over here this + + align:start position:0% +Heat's really coming in over here this + + + align:start position:0% +Heat's really coming in over here this +ends hotter this ends it cooler right + + align:start position:0% +ends hotter this ends it cooler right + + + align:start position:0% +ends hotter this ends it cooler right +it's not got spatially it doesn't have + + align:start position:0% +it's not got spatially it doesn't have + + + align:start position:0% +it's not got spatially it doesn't have +the same temperature + + align:start position:0% +the same temperature + + + align:start position:0% +the same temperature +everywhere right and maybe even + + align:start position:0% +everywhere right and maybe even + + + align:start position:0% +everywhere right and maybe even +temporally it doesn't have the same + + align:start position:0% +temporally it doesn't have the same + + + align:start position:0% +temporally it doesn't have the same +temperature everywhere if I'm not happy + + align:start position:0% +temperature everywhere if I'm not happy + + + align:start position:0% +temperature everywhere if I'm not happy +with this model I can break it up into + + align:start position:0% +with this model I can break it up into + + + align:start position:0% +with this model I can break it up into +more lumps right so I can come over and + + align:start position:0% +more lumps right so I can come over and + + + align:start position:0% +more lumps right so I can come over and +say okay um here's my + + align:start position:0% +say okay um here's my + + + align:start position:0% +say okay um here's my +Beast right let me break this up into + + align:start position:0% +Beast right let me break this up into + + + align:start position:0% +Beast right let me break this up into +T1 T2 + + align:start position:0% +T1 T2 + + + align:start position:0% +T1 T2 +here's T ambient right here's Q right + + align:start position:0% +here's T ambient right here's Q right + + + align:start position:0% +here's T ambient right here's Q right +and now I have a different thermal model + + align:start position:0% +and now I have a different thermal model + + + align:start position:0% +and now I have a different thermal model +right I have q coming + + align:start position:0% +right I have q coming + + + align:start position:0% +right I have q coming +in I could say okay + + align:start position:0% +in I could say okay + + + align:start position:0% +in I could say okay +here's + + align:start position:0% +here's + + + align:start position:0% +here's +cth1 for just this + + align:start position:0% +cth1 for just this + + + align:start position:0% +cth1 for just this +region here's + + align:start position:0% +region here's + + + align:start position:0% +region here's +rth 1 to2 which is the thermal + + align:start position:0% +rth 1 to2 which is the thermal + + + align:start position:0% +rth 1 to2 which is the thermal +resistance here here's cth for + + align:start position:0% + + + + align:start position:0% + +this + + align:start position:0% +this + + + align:start position:0% +this +block and here's the thermal + + align:start position:0% +block and here's the thermal + + + align:start position:0% +block and here's the thermal +resistance coming back to ambient here + + align:start position:0% +resistance coming back to ambient here + + + align:start position:0% +resistance coming back to ambient here +and this is going to be + + align:start position:0% +and this is going to be + + + align:start position:0% +and this is going to be +T2 this is going to be T1 right and now + + align:start position:0% +T2 this is going to be T1 right and now + + + align:start position:0% +T2 this is going to be T1 right and now +I have something that's more spatially + + align:start position:0% +I have something that's more spatially + + + align:start position:0% +I have something that's more spatially +accurate right if all things were equal + + align:start position:0% +accurate right if all things were equal + + + align:start position:0% +accurate right if all things were equal +rth cth would be sort of a factor of + + align:start position:0% +rth cth would be sort of a factor of + + + align:start position:0% +rth cth would be sort of a factor of +four smaller I'd get better time + + align:start position:0% +four smaller I'd get better time + + + align:start position:0% +four smaller I'd get better time +resolution and better spatial resolution + + align:start position:0% +resolution and better spatial resolution + + + align:start position:0% +resolution and better spatial resolution +as to how I'm modeling my system if I + + align:start position:0% +as to how I'm modeling my system if I + + + align:start position:0% +as to how I'm modeling my system if I +carry this to an ex + + align:start position:0% +carry this to an ex + + + align:start position:0% +carry this to an ex +I get basically in back to Foria heat + + align:start position:0% +I get basically in back to Foria heat + + + align:start position:0% +I get basically in back to Foria heat +transfer in partial differential + + align:start position:0% +transfer in partial differential + + + align:start position:0% +transfer in partial differential +equations so this is sort of your best + + align:start position:0% +equations so this is sort of your best + + + align:start position:0% +equations so this is sort of your best +lumped model approximation to 4A heat + + align:start position:0% + + + + align:start position:0% + +transfer any other + + align:start position:0% + + + + align:start position:0% + +questions + + align:start position:0% +questions + + + align:start position:0% +questions +okay um how do + + align:start position:0% +okay um how do + + + align:start position:0% +okay um how do +people model + + align:start position:0% +people model + + + align:start position:0% +people model +this in you + + align:start position:0% +this in you + + + align:start position:0% +this in you +know you know say the thermal capacity + + align:start position:0% +know you know say the thermal capacity + + + align:start position:0% +know you know say the thermal capacity +aspect sometimes you can look up the + + align:start position:0% +aspect sometimes you can look up the + + + align:start position:0% +aspect sometimes you can look up the +ther like if you have a material you can + + align:start position:0% +ther like if you have a material you can + + + align:start position:0% +ther like if you have a material you can +go look up its heat capacity and then + + align:start position:0% +go look up its heat capacity and then + + + align:start position:0% +go look up its heat capacity and then +multiply by the mass and you get a + + align:start position:0% +multiply by the mass and you get a + + + align:start position:0% +multiply by the mass and you get a +thermal capacitance and you can do do it + + align:start position:0% +thermal capacitance and you can do do it + + + align:start position:0% +thermal capacitance and you can do do it +from fundamentals this way that's not + + align:start position:0% +from fundamentals this way that's not + + + align:start position:0% +from fundamentals this way that's not +always the way they give it to you for a + + align:start position:0% +always the way they give it to you for a + + + align:start position:0% +always the way they give it to you for a +device right because if I think about it + + align:start position:0% +device right because if I think about it + + + align:start position:0% +device right because if I think about it +a device is kind of a complicated thing + + align:start position:0% +a device is kind of a complicated thing + + + align:start position:0% +a device is kind of a complicated thing +right there's the silicon and then maybe + + align:start position:0% +right there's the silicon and then maybe + + + align:start position:0% +right there's the silicon and then maybe +inside there's some header and there's + + align:start position:0% +inside there's some header and there's + + + align:start position:0% +inside there's some header and there's +you know different stuff going on + + align:start position:0% +you know different stuff going on + + + align:start position:0% +you know different stuff going on +sometimes what they will do is they will + + align:start position:0% +sometimes what they will do is they will + + + align:start position:0% +sometimes what they will do is they will +give you a + + align:start position:0% +give you a + + + align:start position:0% +give you a +lumped + + align:start position:0% +lumped + + + align:start position:0% +lumped +model and unfortunately this is often + + align:start position:0% +model and unfortunately this is often + + + align:start position:0% +model and unfortunately this is often +called a uh + + align:start position:0% + + + + align:start position:0% + +transient thermal + + align:start position:0% + + + + align:start position:0% + +impedance or + + align:start position:0% +impedance or + + + align:start position:0% +impedance or +zth and it's a kind I say unfortunately + + align:start position:0% +zth and it's a kind I say unfortunately + + + align:start position:0% +zth and it's a kind I say unfortunately +because it's not an impedance in the way + + align:start position:0% +because it's not an impedance in the way + + + align:start position:0% +because it's not an impedance in the way +you think about an impedance is a + + align:start position:0% +you think about an impedance is a + + + align:start position:0% +you think about an impedance is a +frequency domain thing right + + align:start position:0% +frequency domain thing right + + + align:start position:0% +frequency domain thing right +but this is just the language that is + + align:start position:0% +but this is just the language that is + + + align:start position:0% +but this is just the language that is +stuck it's unfortunate but that's what + + align:start position:0% +stuck it's unfortunate but that's what + + + align:start position:0% +stuck it's unfortunate but that's what +they call it but it's not an impedance + + align:start position:0% +they call it but it's not an impedance + + + align:start position:0% +they call it but it's not an impedance +at all here is an example this is the + + align:start position:0% +at all here is an example this is the + + + align:start position:0% +at all here is an example this is the +transient they or here they actually + + align:start position:0% +transient they or here they actually + + + align:start position:0% +transient they or here they actually +they they they call it the maximum + + align:start position:0% +they they they call it the maximum + + + align:start position:0% +they they they call it the maximum +effective transient thermal impedance + + align:start position:0% +effective transient thermal impedance + + + align:start position:0% +effective transient thermal impedance +Junction to + + align:start position:0% +Junction to + + + align:start position:0% +Junction to +case so what does this thing mean this + + align:start position:0% +case so what does this thing mean this + + + align:start position:0% +case so what does this thing mean this +thing means if I took the device + + align:start position:0% +thing means if I took the device + + + align:start position:0% +thing means if I took the device +case and I mounted it against a really + + align:start position:0% +case and I mounted it against a really + + + align:start position:0% +case and I mounted it against a really +Mega good heat sink that's just going to + + align:start position:0% +Mega good heat sink that's just going to + + + align:start position:0% +Mega good heat sink that's just going to +hold the temperature exactly at ambient + + align:start position:0% +hold the temperature exactly at ambient + + + align:start position:0% +hold the temperature exactly at ambient +okay a perfect heat + + align:start position:0% +okay a perfect heat + + + align:start position:0% +okay a perfect heat +SN + + align:start position:0% +SN + + + align:start position:0% +SN +then I steep the power into it and when + + align:start position:0% +then I steep the power into it and when + + + align:start position:0% +then I steep the power into it and when +they say a single pulse what this really + + align:start position:0% +they say a single pulse what this really + + + align:start position:0% +they say a single pulse what this really +is is a plot of the step response it's + + align:start position:0% +is is a plot of the step response it's + + + align:start position:0% +is is a plot of the step response it's +basically this plot for the junction + + align:start position:0% +basically this plot for the junction + + + align:start position:0% +basically this plot for the junction +temperature above the case where the + + align:start position:0% +temperature above the case where the + + + align:start position:0% +temperature above the case where the +case is held exactly at constant right + + align:start position:0% +case is held exactly at constant right + + + align:start position:0% +case is held exactly at constant right +so what this is saying is if I put if I + + align:start position:0% +so what this is saying is if I put if I + + + align:start position:0% +so what this is saying is if I put if I +put one pulse into this + + align:start position:0% +put one pulse into this + + + align:start position:0% +put one pulse into this +device um and I waited 10 the minus 4 + + align:start position:0% +device um and I waited 10 the minus 4 + + + align:start position:0% +device um and I waited 10 the minus 4 +seconds I would have a 0.1 degre C per + + align:start position:0% +seconds I would have a 0.1 degre C per + + + align:start position:0% +seconds I would have a 0.1 degre C per +watt of that + + align:start position:0% +watt of that + + + align:start position:0% +watt of that +step rise so if I had a 10 watt step I'd + + align:start position:0% +step rise so if I had a 10 watt step I'd + + + align:start position:0% +step rise so if I had a 10 watt step I'd +have a one degre C rise after uh 100 + + align:start position:0% +have a one degre C rise after uh 100 + + + align:start position:0% +have a one degre C rise after uh 100 +micros seconds after a millisecond I'd + + align:start position:0% +micros seconds after a millisecond I'd + + + align:start position:0% +micros seconds after a millisecond I'd +have um a higher value Etc so this curve + + align:start position:0% +have um a higher value Etc so this curve + + + align:start position:0% +have um a higher value Etc so this curve +oh you can't yeah if you can see my + + align:start position:0% +oh you can't yeah if you can see my + + + align:start position:0% +oh you can't yeah if you can see my +cursor right this curve is really a log + + align:start position:0% +cursor right this curve is really a log + + + align:start position:0% +cursor right this curve is really a log +log plot of the step + + align:start position:0% +log plot of the step + + + align:start position:0% +log plot of the step +response okay if it has one time const + + align:start position:0% +response okay if it has one time const + + + align:start position:0% +response okay if it has one time const +it would look like one thing if it has + + align:start position:0% +it would look like one thing if it has + + + align:start position:0% +it would look like one thing if it has +multiple time constants you know the + + align:start position:0% +multiple time constants you know the + + + align:start position:0% +multiple time constants you know the +shape of this curve changes okay so a + + align:start position:0% +shape of this curve changes okay so a + + + align:start position:0% +shape of this curve changes okay so a +transient thermal impedance what they're + + align:start position:0% +transient thermal impedance what they're + + + align:start position:0% +transient thermal impedance what they're +really telling you is essentially this + + align:start position:0% +really telling you is essentially this + + + align:start position:0% +really telling you is essentially this +step response for the device assuming + + align:start position:0% +step response for the device assuming + + + align:start position:0% +step response for the device assuming +it's against the perfect heat + + align:start position:0% +it's against the perfect heat + + + align:start position:0% +it's against the perfect heat +sink okay what they also sometimes tell + + align:start position:0% +sink okay what they also sometimes tell + + + align:start position:0% +sink okay what they also sometimes tell +you is if I now have little pulses I + + align:start position:0% +you is if I now have little pulses I + + + align:start position:0% +you is if I now have little pulses I +step it up and I step it down and I wait + + align:start position:0% +step it up and I step it down and I wait + + + align:start position:0% +step it up and I step it down and I wait +a while I step it up and I step it down + + align:start position:0% +a while I step it up and I step it down + + + align:start position:0% +a while I step it up and I step it down +and wait a while they will tell you the + + align:start position:0% +and wait a while they will tell you the + + + align:start position:0% +and wait a while they will tell you the +maximum temperature it'll get during the + + align:start position:0% +maximum temperature it'll get during the + + + align:start position:0% +maximum temperature it'll get during the +step for different Duty ratios of pulses + + align:start position:0% +step for different Duty ratios of pulses + + + align:start position:0% +step for different Duty ratios of pulses +all right why do they tell you this + + align:start position:0% +all right why do they tell you this + + + align:start position:0% +all right why do they tell you this +because look if I put 100 watts into + + align:start position:0% +because look if I put 100 watts into + + + align:start position:0% +because look if I put 100 watts into +this device + + align:start position:0% +this device + + + align:start position:0% +this device +continuously and I put the case at 0 + + align:start position:0% +continuously and I put the case at 0 + + + align:start position:0% +continuously and I put the case at 0 +degrees C and I held it there + + align:start position:0% +degrees C and I held it there + + + align:start position:0% +degrees C and I held it there +continuously what this would say is 100 + + align:start position:0% +continuously what this would say is 100 + + + align:start position:0% +continuously what this would say is 100 +time you know 2.5 would give me 250 + + align:start position:0% +time you know 2.5 would give me 250 + + + align:start position:0% +time you know 2.5 would give me 250 +degre C rise right well that' blow the + + align:start position:0% +degre C rise right well that' blow the + + + align:start position:0% +degre C rise right well that' blow the +thing + + align:start position:0% +thing + + + align:start position:0% +thing +up right because this said 150 degre C + + align:start position:0% +up right because this said 150 degre C + + + align:start position:0% +up right because this said 150 degre C +device but if I only did it for a + + align:start position:0% +device but if I only did it for a + + + align:start position:0% +device but if I only did it for a +millisecond this thing would tell me + + align:start position:0% +millisecond this thing would tell me + + + align:start position:0% +millisecond this thing would tell me +that I'd have only 0.1 point2 + + align:start position:0% +that I'd have only 0.1 point2 + + + align:start position:0% +that I'd have only 0.1 point2 +you know I'd be right here on the curve + + align:start position:0% +you know I'd be right here on the curve + + + align:start position:0% +you know I'd be right here on the curve +like3 degrees C per watt and maybe it + + align:start position:0% +like3 degrees C per watt and maybe it + + + align:start position:0% +like3 degrees C per watt and maybe it +would only go up 30°c so I can have a + + align:start position:0% +would only go up 30°c so I can have a + + + align:start position:0% +would only go up 30°c so I can have a +one millisecond pulse that's really big + + align:start position:0% +one millisecond pulse that's really big + + + align:start position:0% +one millisecond pulse that's really big +and it won't kill the device because of + + align:start position:0% +and it won't kill the device because of + + + align:start position:0% +and it won't kill the device because of +the thermal capacitance of the device in + + align:start position:0% +the thermal capacitance of the device in + + + align:start position:0% +the thermal capacitance of the device in +its package okay so thermal transient + + align:start position:0% +its package okay so thermal transient + + + align:start position:0% +its package okay so thermal transient +thermal impedance is a step response + + align:start position:0% +thermal impedance is a step response + + + align:start position:0% +thermal impedance is a step response +plotted on a log log plot + + align:start position:0% +plotted on a log log plot + + + align:start position:0% +plotted on a log log plot +okay the other thing I should tell you + + align:start position:0% +okay the other thing I should tell you + + + align:start position:0% +okay the other thing I should tell you +is that you know you could somehow + + align:start position:0% +is that you know you could somehow + + + align:start position:0% +is that you know you could somehow +extract that model and come up with a + + align:start position:0% +extract that model and come up with a + + + align:start position:0% +extract that model and come up with a +thermal model for the device maybe it's + + align:start position:0% +thermal model for the device maybe it's + + + align:start position:0% +thermal model for the device maybe it's +only one RC that you approximate it with + + align:start position:0% +only one RC that you approximate it with + + + align:start position:0% +only one RC that you approximate it with +okay but in a complicated big you know + + align:start position:0% +okay but in a complicated big you know + + + align:start position:0% +okay but in a complicated big you know +module it might be a more complicated + + align:start position:0% +module it might be a more complicated + + + align:start position:0% +module it might be a more complicated +model because there might be like the + + align:start position:0% +model because there might be like the + + + align:start position:0% +model because there might be like the +thermal capacitance of the Silicon the + + align:start position:0% +thermal capacitance of the Silicon the + + + align:start position:0% +thermal capacitance of the Silicon the +thermal capacitance of the header and so + + align:start position:0% +thermal capacitance of the header and so + + + align:start position:0% +thermal capacitance of the header and so +forth right + + align:start position:0% +forth right + + + align:start position:0% +forth right +um You will often see thermal models + + align:start position:0% +um You will often see thermal models + + + align:start position:0% +um You will often see thermal models +this is called a power form Network you + + align:start position:0% +this is called a power form Network you + + + align:start position:0% +this is called a power form Network you +will often see thermal models in data + + align:start position:0% +will often see thermal models in data + + + align:start position:0% +will often see thermal models in data +sheets or appnotes or something that are + + align:start position:0% +sheets or appnotes or something that are + + + align:start position:0% +sheets or appnotes or something that are +something like this + + align:start position:0% + + + + align:start position:0% + +okay and that are done like this the + + align:start position:0% +okay and that are done like this the + + + align:start position:0% +okay and that are done like this the +thermal resistances and thermal + + align:start position:0% +thermal resistances and thermal + + + align:start position:0% +thermal resistances and thermal +capacitances that's sort of a a foster + + align:start position:0% +capacitances that's sort of a a foster + + + align:start position:0% +capacitances that's sort of a a foster +form of network that's just wrong + + align:start position:0% +form of network that's just wrong + + + align:start position:0% +form of network that's just wrong +unfortunately you can kind of try to + + align:start position:0% +unfortunately you can kind of try to + + + align:start position:0% +unfortunately you can kind of try to +take this kind of model and map it over + + align:start position:0% +take this kind of model and map it over + + + align:start position:0% +take this kind of model and map it over +to that kind of model but any real + + align:start position:0% +to that kind of model but any real + + + align:start position:0% +to that kind of model but any real +thermal capacitors you're going to + + align:start position:0% +thermal capacitors you're going to + + + align:start position:0% +thermal capacitors you're going to +represent fora heat transfer thermal + + align:start position:0% +represent fora heat transfer thermal + + + align:start position:0% +represent fora heat transfer thermal +capacitances ought to always be down to + + align:start position:0% +capacitances ought to always be down to + + + align:start position:0% +capacitances ought to always be down to +we can use ambient but it should always + + align:start position:0% +we can use ambient but it should always + + + align:start position:0% +we can use ambient but it should always +technically be absolute zero these are + + align:start position:0% +technically be absolute zero these are + + + align:start position:0% +technically be absolute zero these are +me referencing the thermal capacitance + + align:start position:0% +me referencing the thermal capacitance + + + align:start position:0% +me referencing the thermal capacitance +to other places in the thermal path + + align:start position:0% +to other places in the thermal path + + + align:start position:0% +to other places in the thermal path +where the temperature is changing all + + align:start position:0% +where the temperature is changing all + + + align:start position:0% +where the temperature is changing all +right so it's basically just not right + + align:start position:0% +right so it's basically just not right + + + align:start position:0% +right so it's basically just not right +but people do it because it's + + align:start position:0% +but people do it because it's + + + align:start position:0% +but people do it because it's +convenient and I suppose you know if the + + align:start position:0% +convenient and I suppose you know if the + + + align:start position:0% +convenient and I suppose you know if the +thermal capacitance here or the thermal + + align:start position:0% +thermal capacitance here or the thermal + + + align:start position:0% +thermal capacitance here or the thermal +resistance here was super low maybe it's + + align:start position:0% +resistance here was super low maybe it's + + + align:start position:0% +resistance here was super low maybe it's +almost like this was it Earth so they + + align:start position:0% +almost like this was it Earth so they + + + align:start position:0% +almost like this was it Earth so they +can kind of get away with it sometimes + + align:start position:0% +can kind of get away with it sometimes + + + align:start position:0% +can kind of get away with it sometimes +but it's just a warning if you want to + + align:start position:0% +but it's just a warning if you want to + + + align:start position:0% +but it's just a warning if you want to +stick with the physics this is the + + align:start position:0% +stick with the physics this is the + + + align:start position:0% +stick with the physics this is the +correct kind of model to + + align:start position:0% + + + + align:start position:0% + +use so that's just giving you a heads up + + align:start position:0% +use so that's just giving you a heads up + + + align:start position:0% +use so that's just giving you a heads up +I want to just tell you about two more + + align:start position:0% +I want to just tell you about two more + + + align:start position:0% +I want to just tell you about two more +things what I've told you so far is if I + + align:start position:0% +things what I've told you so far is if I + + + align:start position:0% +things what I've told you so far is if I +have like a big package that I'm going + + align:start position:0% +have like a big package that I'm going + + + align:start position:0% +have like a big package that I'm going +to mount it against the heat sink and + + align:start position:0% +to mount it against the heat sink and + + + align:start position:0% +to mount it against the heat sink and +that's a very typical thing you have to + + align:start position:0% +that's a very typical thing you have to + + + align:start position:0% +that's a very typical thing you have to +do in some cases and and in a lot of + + align:start position:0% +do in some cases and and in a lot of + + + align:start position:0% +do in some cases and and in a lot of +designs it doesn't work that way you + + align:start position:0% +designs it doesn't work that way you + + + align:start position:0% +designs it doesn't work that way you +might have something like this here's my + + align:start position:0% +might have something like this here's my + + + align:start position:0% +might have something like this here's my +device that I might Mount instead of + + align:start position:0% +device that I might Mount instead of + + + align:start position:0% +device that I might Mount instead of +mounting my device directly to a heat + + align:start position:0% +mounting my device directly to a heat + + + align:start position:0% +mounting my device directly to a heat +sink right you will often have a circuit + + align:start position:0% +sink right you will often have a circuit + + + align:start position:0% +sink right you will often have a circuit +board here's my circuit board okay and + + align:start position:0% +board here's my circuit board okay and + + + align:start position:0% +board here's my circuit board okay and +I'll have some device and maybe this + + align:start position:0% +I'll have some device and maybe this + + + align:start position:0% +I'll have some device and maybe this +device will have a a heat pad you know + + align:start position:0% +device will have a a heat pad you know + + + align:start position:0% +device will have a a heat pad you know +here's my package it'll have a bunch of + + align:start position:0% +here's my package it'll have a bunch of + + + align:start position:0% +here's my package it'll have a bunch of +electrical connections off the device + + align:start position:0% +electrical connections off the device + + + align:start position:0% +electrical connections off the device +onto the circuit board right so the + + align:start position:0% +onto the circuit board right so the + + + align:start position:0% +onto the circuit board right so the +first thing I do is I mount my device to + + align:start position:0% +first thing I do is I mount my device to + + + align:start position:0% +first thing I do is I mount my device to +the CC circuit + + align:start position:0% +the CC circuit + + + align:start position:0% +the CC circuit +board okay and my electrical connections + + align:start position:0% +board okay and my electrical connections + + + align:start position:0% +board okay and my electrical connections +would come off of that right you know + + align:start position:0% +would come off of that right you know + + + align:start position:0% +would come off of that right you know +I'd run my gate and my source right I'd + + align:start position:0% +I'd run my gate and my source right I'd + + + align:start position:0% +I'd run my gate and my source right I'd +have a bunch of wires on the circuit + + align:start position:0% +have a bunch of wires on the circuit + + + align:start position:0% +have a bunch of wires on the circuit +board going different places so I've + + align:start position:0% +board going different places so I've + + + align:start position:0% +board going different places so I've +made my electrical connection to device + + align:start position:0% +made my electrical connection to device + + + align:start position:0% +made my electrical connection to device +but now I also need to get the heat out + + align:start position:0% +but now I also need to get the heat out + + + align:start position:0% +but now I also need to get the heat out +of it right so what do I do often what + + align:start position:0% +of it right so what do I do often what + + + align:start position:0% +of it right so what do I do often what +you do is you instead of trying to mount + + align:start position:0% +you do is you instead of trying to mount + + + align:start position:0% +you do is you instead of trying to mount +the device directly against the heat + + align:start position:0% +the device directly against the heat + + + align:start position:0% +the device directly against the heat +sink you mount the device to the board + + align:start position:0% +sink you mount the device to the board + + + align:start position:0% +sink you mount the device to the board +carry the heat through the board and + + align:start position:0% +carry the heat through the board and + + + align:start position:0% +carry the heat through the board and +then to a heat sink on the other side so + + align:start position:0% +then to a heat sink on the other side so + + + align:start position:0% +then to a heat sink on the other side so +maybe what I would do + + align:start position:0% +maybe what I would do + + + align:start position:0% +maybe what I would do +is on the other side of the board maybe + + align:start position:0% +is on the other side of the board maybe + + + align:start position:0% +is on the other side of the board maybe +I would put a thermal interface pad + + align:start position:0% +I would put a thermal interface pad + + + align:start position:0% +I would put a thermal interface pad +right and then a heat + + align:start position:0% +right and then a heat + + + align:start position:0% +right and then a heat +sink you know the heat sink's mounted to + + align:start position:0% +sink you know the heat sink's mounted to + + + align:start position:0% +sink you know the heat sink's mounted to +the other side of the + + align:start position:0% +the other side of the + + + align:start position:0% +the other side of the +board okay and I'm going to try to get + + align:start position:0% +board okay and I'm going to try to get + + + align:start position:0% +board okay and I'm going to try to get +heat out of the device through the + + align:start position:0% +heat out of the device through the + + + align:start position:0% +heat out of the device through the +package through the board through the + + align:start position:0% +package through the board through the + + + align:start position:0% +package through the board through the +interface material into the heat + + align:start position:0% +interface material into the heat + + + align:start position:0% +interface material into the heat +sink and this is necessary because you + + align:start position:0% +sink and this is necessary because you + + + align:start position:0% +sink and this is necessary because you +want to connect the device to the board + + align:start position:0% +want to connect the device to the board + + + align:start position:0% +want to connect the device to the board +for the electrical connection is the + + align:start position:0% +for the electrical connection is the + + + align:start position:0% +for the electrical connection is the +most important thing okay so one of the + + align:start position:0% +most important thing okay so one of the + + + align:start position:0% +most important thing okay so one of the +things you often do is you will often + + align:start position:0% +things you often do is you will often + + + align:start position:0% +things you often do is you will often +put thermal vas in the board so what + + align:start position:0% +put thermal vas in the board so what + + + align:start position:0% +put thermal vas in the board so what +you'll do is you go to the board and if + + align:start position:0% +you'll do is you go to the board and if + + + align:start position:0% +you'll do is you go to the board and if +I looked at this from the side you'll + + align:start position:0% +I looked at this from the side you'll + + + align:start position:0% +I looked at this from the side you'll +drill a bunch of holes through the board + + align:start position:0% +drill a bunch of holes through the board + + + align:start position:0% +drill a bunch of holes through the board +you'll put holes in the board like this + + align:start position:0% +you'll put holes in the board like this + + + align:start position:0% +you'll put holes in the board like this +and you'll put what's known as a via + + align:start position:0% +and you'll put what's known as a via + + + align:start position:0% +and you'll put what's known as a via +Farm okay if I looked straight down on + + align:start position:0% +Farm okay if I looked straight down on + + + align:start position:0% +Farm okay if I looked straight down on +top of it you'd see a bunch of holes + + align:start position:0% +top of it you'd see a bunch of holes + + + align:start position:0% +top of it you'd see a bunch of holes +driel in the board like this okay why + + align:start position:0% +driel in the board like this okay why + + + align:start position:0% +driel in the board like this okay why +because those holes will then be played + + align:start position:0% +because those holes will then be played + + + align:start position:0% +because those holes will then be played +with copper which is a good thermal + + align:start position:0% +with copper which is a good thermal + + + align:start position:0% +with copper which is a good thermal +conductor and I it'll help me transfer + + align:start position:0% +conductor and I it'll help me transfer + + + align:start position:0% +conductor and I it'll help me transfer +heat through down through the board to + + align:start position:0% +heat through down through the board to + + + align:start position:0% +heat through down through the board to +the interface material to the heat sink + + align:start position:0% +the interface material to the heat sink + + + align:start position:0% +the interface material to the heat sink +sometimes you fill those holes with + + align:start position:0% +sometimes you fill those holes with + + + align:start position:0% +sometimes you fill those holes with +copper and a fancy board or you fill it + + align:start position:0% +copper and a fancy board or you fill it + + + align:start position:0% +copper and a fancy board or you fill it +with thermally conductive epoxy to help + + align:start position:0% +with thermally conductive epoxy to help + + + align:start position:0% +with thermally conductive epoxy to help +the heat transfer through the board + + align:start position:0% +the heat transfer through the board + + + align:start position:0% +the heat transfer through the board +sometimes you'll try to use a thin board + + align:start position:0% +sometimes you'll try to use a thin board + + + align:start position:0% +sometimes you'll try to use a thin board +so that you have lower thermal + + align:start position:0% +so that you have lower thermal + + + align:start position:0% +so that you have lower thermal +resistance right um this + + align:start position:0% +resistance right um this + + + align:start position:0% +resistance right um this +appnote that uh you'll be provided with + + align:start position:0% +appnote that uh you'll be provided with + + + align:start position:0% +appnote that uh you'll be provided with +in the handouts talks about okay if I + + align:start position:0% +in the handouts talks about okay if I + + + align:start position:0% +in the handouts talks about okay if I +have thermal Vias of a certain length um + + align:start position:0% +have thermal Vias of a certain length um + + + align:start position:0% +have thermal Vias of a certain length um +how many degrees C per watt for a 12 mil + + align:start position:0% +how many degrees C per watt for a 12 mil + + + align:start position:0% +how many degrees C per watt for a 12 mil +via going through a 63 mil board and so + + align:start position:0% +via going through a 63 mil board and so + + + align:start position:0% +via going through a 63 mil board and so +forth you can figure out your thermal + + align:start position:0% +forth you can figure out your thermal + + + align:start position:0% +forth you can figure out your thermal +model transferring your heat through the + + align:start position:0% +model transferring your heat through the + + + align:start position:0% +model transferring your heat through the +circuit + + align:start position:0% +circuit + + + align:start position:0% +circuit +board okay so that's just a heads up + + align:start position:0% +board okay so that's just a heads up + + + align:start position:0% +board okay so that's just a heads up +about how you might do things for PC + + align:start position:0% +about how you might do things for PC + + + align:start position:0% +about how you might do things for PC +board mounted + + align:start position:0% +board mounted + + + align:start position:0% +board mounted +components the last thing I'd like to do + + align:start position:0% +components the last thing I'd like to do + + + align:start position:0% +components the last thing I'd like to do +for you today any questions about + + align:start position:0% +for you today any questions about + + + align:start position:0% +for you today any questions about +that the last thing I wanted to do for + + align:start position:0% +that the last thing I wanted to do for + + + align:start position:0% +that the last thing I wanted to do for +you today is just show you a thermal + + align:start position:0% +you today is just show you a thermal + + + align:start position:0% +you today is just show you a thermal +transfer + + align:start position:0% +transfer + + + align:start position:0% +transfer +example okay so here we go go here's the + + align:start position:0% +example okay so here we go go here's the + + + align:start position:0% +example okay so here we go go here's the +thing I'm going to show you this is for + + align:start position:0% +thing I'm going to show you this is for + + + align:start position:0% +thing I'm going to show you this is for +a particular matching Network design + + align:start position:0% +a particular matching Network design + + + align:start position:0% +a particular matching Network design +that we did and this thing has these + + align:start position:0% +that we did and this thing has these + + + align:start position:0% +that we did and this thing has these +four transistors that are mounted + + align:start position:0% +four transistors that are mounted + + + align:start position:0% +four transistors that are mounted +between the circuit and + + align:start position:0% +between the circuit and + + + align:start position:0% +between the circuit and +ground okay each of these transistors + + align:start position:0% +ground okay each of these transistors + + + align:start position:0% +ground okay each of these transistors +can dissipate like something like 30 + + align:start position:0% +can dissipate like something like 30 + + + align:start position:0% +can dissipate like something like 30 +watts in the worst case high power + + align:start position:0% +watts in the worst case high power + + + align:start position:0% +watts in the worst case high power +design okay so four devices times 30 + + align:start position:0% +design okay so four devices times 30 + + + align:start position:0% +design okay so four devices times 30 +watts is like what's 33 w roughly + + align:start position:0% +watts is like what's 33 w roughly + + + align:start position:0% +watts is like what's 33 w roughly +speaking it's like 140 Watts something + + align:start position:0% +speaking it's like 140 Watts something + + + align:start position:0% +speaking it's like 140 Watts something +like that 13 wats okay that's a lot of + + align:start position:0% +like that 13 wats okay that's a lot of + + + align:start position:0% +like that 13 wats okay that's a lot of +heat to pull out of these little devices + + align:start position:0% +heat to pull out of these little devices + + + align:start position:0% +heat to pull out of these little devices +okay here's the here's the devices okay + + align:start position:0% +okay here's the here's the devices okay + + + align:start position:0% +okay here's the here's the devices okay +these are the package one side of this + + align:start position:0% +these are the package one side of this + + + align:start position:0% +these are the package one side of this +has these electrical connections to the + + align:start position:0% +has these electrical connections to the + + + align:start position:0% +has these electrical connections to the +devices and the other side of this has a + + align:start position:0% +devices and the other side of this has a + + + align:start position:0% +devices and the other side of this has a +big thermal pad out of which the Heat's + + align:start position:0% +big thermal pad out of which the Heat's + + + align:start position:0% +big thermal pad out of which the Heat's +supposed to come so this is a + + align:start position:0% +supposed to come so this is a + + + align:start position:0% +supposed to come so this is a +two-sided device where you you have + + align:start position:0% +two-sided device where you you have + + + align:start position:0% +two-sided device where you you have +electrical connections on one side and a + + align:start position:0% +electrical connections on one side and a + + + align:start position:0% +electrical connections on one side and a +thermal pad for heat transfer on the + + align:start position:0% +thermal pad for heat transfer on the + + + align:start position:0% +thermal pad for heat transfer on the +other side of the device okay so one + + align:start position:0% +other side of the device okay so one + + + align:start position:0% +other side of the device okay so one +side of this device the side that's + + align:start position:0% +side of this device the side that's + + + align:start position:0% +side of this device the side that's +showing flat here is going to be + + align:start position:0% +showing flat here is going to be + + + align:start position:0% +showing flat here is going to be +connected to the circuit board and the + + align:start position:0% +connected to the circuit board and the + + + align:start position:0% +connected to the circuit board and the +other side of the device we're going to + + align:start position:0% +other side of the device we're going to + + + align:start position:0% +other side of the device we're going to +want to connect to the heat sink okay so + + align:start position:0% +want to connect to the heat sink okay so + + + align:start position:0% +want to connect to the heat sink okay so +what do we do uh here you can see one + + align:start position:0% +what do we do uh here you can see one + + + align:start position:0% +what do we do uh here you can see one +side this is the top side of the circuit + + align:start position:0% +side this is the top side of the circuit + + + align:start position:0% +side this is the top side of the circuit +board this is not the side of the + + align:start position:0% +board this is not the side of the + + + align:start position:0% +board this is not the side of the +circuit board where the devices are on + + align:start position:0% +circuit board where the devices are on + + + align:start position:0% +circuit board where the devices are on +the devices are mounted to the bottom + + align:start position:0% +the devices are mounted to the bottom + + + align:start position:0% +the devices are mounted to the bottom +side of the circuit board and part of + + align:start position:0% +side of the circuit board and part of + + + align:start position:0% +side of the circuit board and part of +the bottom side of the circuit board is + + align:start position:0% +the bottom side of the circuit board is + + + align:start position:0% +the bottom side of the circuit board is +this silver ground plane you see here + + align:start position:0% +this silver ground plane you see here + + + align:start position:0% +this silver ground plane you see here +these are the devices the side of the + + align:start position:0% +these are the devices the side of the + + + align:start position:0% +these are the devices the side of the +device you cannot see is what's got the + + align:start position:0% +device you cannot see is what's got the + + + align:start position:0% +device you cannot see is what's got the +electrical connections for the drain and + + align:start position:0% +electrical connections for the drain and + + + align:start position:0% +electrical connections for the drain and +the gate and the source and the drivers + + align:start position:0% +the gate and the source and the drivers + + + align:start position:0% +the gate and the source and the drivers +and the drivers are all on this side of + + align:start position:0% +and the drivers are all on this side of + + + align:start position:0% +and the drivers are all on this side of +the board okay so what's exposed here on + + align:start position:0% +the board okay so what's exposed here on + + + align:start position:0% +the board okay so what's exposed here on +the bottom side of the board is the uh + + align:start position:0% +the bottom side of the board is the uh + + + align:start position:0% +the bottom side of the board is the uh +heat pad through which I'm going to try + + align:start position:0% +heat pad through which I'm going to try + + + align:start position:0% +heat pad through which I'm going to try +to transfer + + align:start position:0% +to transfer + + + align:start position:0% +to transfer +heat so what do we do we created a a + + align:start position:0% +heat so what do we do we created a a + + + align:start position:0% +heat so what do we do we created a a +heat + + align:start position:0% +heat + + + align:start position:0% +heat +spreader okay because we're going to + + align:start position:0% +spreader okay because we're going to + + + align:start position:0% +spreader okay because we're going to +flip this board over and bang down on + + align:start position:0% +flip this board over and bang down on + + + align:start position:0% +flip this board over and bang down on +the heat spreader you notice that the + + align:start position:0% +the heat spreader you notice that the + + + align:start position:0% +the heat spreader you notice that the +heat spreader has some like some area + + align:start position:0% +heat spreader has some like some area + + + align:start position:0% +heat spreader has some like some area +mil out right so if you look at this + + align:start position:0% +mil out right so if you look at this + + + align:start position:0% +mil out right so if you look at this +right there's a space + + align:start position:0% +right there's a space + + + align:start position:0% +right there's a space +for the devices to sit in this space in + + align:start position:0% +for the devices to sit in this space in + + + align:start position:0% +for the devices to sit in this space in +these four spaces for the four devices + + align:start position:0% +these four spaces for the four devices + + + align:start position:0% +these four spaces for the four devices +okay so that the circuit board will sit + + align:start position:0% +okay so that the circuit board will sit + + + align:start position:0% +okay so that the circuit board will sit +flat with the heat spreader and then the + + align:start position:0% +flat with the heat spreader and then the + + + align:start position:0% +flat with the heat spreader and then the +devices will s down and sit flat against + + align:start position:0% +devices will s down and sit flat against + + + align:start position:0% +devices will s down and sit flat against +the Little M out + + align:start position:0% +the Little M out + + + align:start position:0% +the Little M out +area um these little circles here are + + align:start position:0% +area um these little circles here are + + + align:start position:0% +area um these little circles here are +just areas for extra solder to flow out + + align:start position:0% +just areas for extra solder to flow out + + + align:start position:0% +just areas for extra solder to flow out +of the device okay so what we're going + + align:start position:0% +of the device okay so what we're going + + + align:start position:0% +of the device okay so what we're going +to do is we have the device soldered to + + align:start position:0% +to do is we have the device soldered to + + + align:start position:0% +to do is we have the device soldered to +the board and then we're going to solder + + align:start position:0% +the board and then we're going to solder + + + align:start position:0% +the board and then we're going to solder +it to this heat spreader okay how do we + + align:start position:0% +it to this heat spreader okay how do we + + + align:start position:0% +it to this heat spreader okay how do we +make that work well the first thing we + + align:start position:0% +make that work well the first thing we + + + align:start position:0% +make that work well the first thing we +do is we solder the circuit the the all + + align:start position:0% +do is we solder the circuit the the all + + + align:start position:0% +do is we solder the circuit the the all +the chips to the board with high + + align:start position:0% +the chips to the board with high + + + align:start position:0% +the chips to the board with high +temperature solder so then then I I've + + align:start position:0% +temperature solder so then then I I've + + + align:start position:0% +temperature solder so then then I I've +mounted my device to the board now I put + + align:start position:0% +mounted my device to the board now I put + + + align:start position:0% +mounted my device to the board now I put +thermal I put solder ball I put solder + + align:start position:0% +thermal I put solder ball I put solder + + + align:start position:0% +thermal I put solder ball I put solder +paste on it here you can see the dots of + + align:start position:0% +paste on it here you can see the dots of + + + align:start position:0% +paste on it here you can see the dots of +solder paste I flip this thing over + + align:start position:0% +solder paste I flip this thing over + + + align:start position:0% +solder paste I flip this thing over +under this heat sink and then I Reflow + + align:start position:0% +under this heat sink and then I Reflow + + + align:start position:0% +under this heat sink and then I Reflow +it again and this solder is low + + align:start position:0% +it again and this solder is low + + + align:start position:0% +it again and this solder is low +temperature solder so I don't unsolder + + align:start position:0% +temperature solder so I don't unsolder + + + align:start position:0% +temperature solder so I don't unsolder +the the device to the board while I do + + align:start position:0% +the the device to the board while I do + + + align:start position:0% +the the device to the board while I do +solder it to the heat spreader make + + align:start position:0% +solder it to the heat spreader make + + + align:start position:0% +solder it to the heat spreader make +sense everybody okay + + align:start position:0% +sense everybody okay + + + align:start position:0% +sense everybody okay +so we got this hierarchy of temperatures + + align:start position:0% +so we got this hierarchy of temperatures + + + align:start position:0% +so we got this hierarchy of temperatures +of my solder how do I cool this device + + align:start position:0% +of my solder how do I cool this device + + + align:start position:0% +of my solder how do I cool this device +now I got this heat spreader which has + + align:start position:0% +now I got this heat spreader which has + + + align:start position:0% +now I got this heat spreader which has +got like you know really low thermal + + align:start position:0% +got like you know really low thermal + + + align:start position:0% +got like you know really low thermal +resistance now right so I've gone from + + align:start position:0% +resistance now right so I've gone from + + + align:start position:0% +resistance now right so I've gone from +my + + align:start position:0% +my + + + align:start position:0% +my +chip directly to the heat spreader and + + align:start position:0% +chip directly to the heat spreader and + + + align:start position:0% +chip directly to the heat spreader and +by the way I said these um this thermal + + align:start position:0% +by the way I said these um this thermal + + + align:start position:0% +by the way I said these um this thermal +pad on the device is actually Connected + + align:start position:0% +pad on the device is actually Connected + + + align:start position:0% +pad on the device is actually Connected +To Source in this particular device and + + align:start position:0% +To Source in this particular device and + + + align:start position:0% +To Source in this particular device and +source is ground in the particular + + align:start position:0% +source is ground in the particular + + + align:start position:0% +source is ground in the particular +circuit so I can basically make this + + align:start position:0% +circuit so I can basically make this + + + align:start position:0% +circuit so I can basically make this +whole heat spreader and the whole thing + + align:start position:0% +whole heat spreader and the whole thing + + + align:start position:0% +whole heat spreader and the whole thing +electrical ground that's kind kind of + + align:start position:0% +electrical ground that's kind kind of + + + align:start position:0% +electrical ground that's kind kind of +nice here's my so I'm going to connect + + align:start position:0% +nice here's my so I'm going to connect + + + align:start position:0% +nice here's my so I'm going to connect +the heat spreader onto this datatron + + align:start position:0% +the heat spreader onto this datatron + + + align:start position:0% +the heat spreader onto this datatron +copper heat + + align:start position:0% +copper heat + + + align:start position:0% +copper heat +sink okay and here's what you can see + + align:start position:0% +sink okay and here's what you can see + + + align:start position:0% +sink okay and here's what you can see +about the seat sink here's the thermal + + align:start position:0% +about the seat sink here's the thermal + + + align:start position:0% +about the seat sink here's the thermal +resistance to ambient of the heat sink + + align:start position:0% +resistance to ambient of the heat sink + + + align:start position:0% +resistance to ambient of the heat sink +versus air flow so this is where I said + + align:start position:0% +versus air flow so this is where I said + + + align:start position:0% +versus air flow so this is where I said +you know yeah to to to really know this + + align:start position:0% +you know yeah to to to really know this + + + align:start position:0% +you know yeah to to to really know this +heat transfer coefficient is a lot of + + align:start position:0% +heat transfer coefficient is a lot of + + + align:start position:0% +heat transfer coefficient is a lot of +work and to design the heat sink to get + + align:start position:0% +work and to design the heat sink to get + + + align:start position:0% +work and to design the heat sink to get +a low heat transfer Coe or a high heat + + align:start position:0% +a low heat transfer Coe or a high heat + + + align:start position:0% +a low heat transfer Coe or a high heat +transfer coefficient hard but somebody + + align:start position:0% +transfer coefficient hard but somebody + + + align:start position:0% +transfer coefficient hard but somebody +else did did that for me all I got to + + align:start position:0% +else did did that for me all I got to + + + align:start position:0% +else did did that for me all I got to +know is how much air I'm going to blow + + align:start position:0% +know is how much air I'm going to blow + + + align:start position:0% +know is how much air I'm going to blow +across this and I can get down to Crazy + + align:start position:0% +across this and I can get down to Crazy + + + align:start position:0% +across this and I can get down to Crazy +low thermal resistances if this wasn't + + align:start position:0% +low thermal resistances if this wasn't + + + align:start position:0% +low thermal resistances if this wasn't +low enough then I'd have to go to liquid + + align:start position:0% +low enough then I'd have to go to liquid + + + align:start position:0% +low enough then I'd have to go to liquid +cooling and get even lower ones okay but + + align:start position:0% +cooling and get even lower ones okay but + + + align:start position:0% +cooling and get even lower ones okay but +we were able to do it there so all we + + align:start position:0% +we were able to do it there so all we + + + align:start position:0% +we were able to do it there so all we +did was then we basically mounted the + + align:start position:0% +did was then we basically mounted the + + + align:start position:0% +did was then we basically mounted the +device to the heat spreader the heat + + align:start position:0% +device to the heat spreader the heat + + + align:start position:0% +device to the heat spreader the heat +spreader the heat sink and then blew air + + align:start position:0% +spreader the heat sink and then blew air + + + align:start position:0% +spreader the heat sink and then blew air +across it here you can see another view + + align:start position:0% +across it here you can see another view + + + align:start position:0% +across it here you can see another view +of it right here's the heat sink the + + align:start position:0% +of it right here's the heat sink the + + + align:start position:0% +of it right here's the heat sink the +device mounted to it and we're going to + + align:start position:0% +device mounted to it and we're going to + + + align:start position:0% +device mounted to it and we're going to +blow a lot of air to it here's the + + align:start position:0% +blow a lot of air to it here's the + + + align:start position:0% +blow a lot of air to it here's the +actual Beast + + align:start position:0% +actual Beast + + + align:start position:0% +actual Beast +right so you can see here's + + align:start position:0% +right so you can see here's + + + align:start position:0% +right so you can see here's +the the circuit mounted to the heat + + align:start position:0% +the the circuit mounted to the heat + + + align:start position:0% +the the circuit mounted to the heat +spreader the heat sink is now all silver + + align:start position:0% +spreader the heat sink is now all silver + + + align:start position:0% +spreader the heat sink is now all silver +because we silver it's silver colored + + align:start position:0% +because we silver it's silver colored + + + align:start position:0% +because we silver it's silver colored +because we silverplated it okay and here + + align:start position:0% +because we silverplated it okay and here + + + align:start position:0% +because we silverplated it okay and here +you could see the fan blowing air + + align:start position:0% +you could see the fan blowing air + + + align:start position:0% +you could see the fan blowing air +through the fins all right the + + align:start position:0% +through the fins all right the + + + align:start position:0% +through the fins all right the +relativity of that is I said we had like + + align:start position:0% +relativity of that is I said we had like + + + align:start position:0% +relativity of that is I said we had like +um 10 and something watts of heat + + align:start position:0% +um 10 and something watts of heat + + + align:start position:0% +um 10 and something watts of heat +dissipation in the worst case but if you + + align:start position:0% +dissipation in the worst case but if you + + + align:start position:0% +dissipation in the worst case but if you +look at the temperature rises of the + + align:start position:0% +look at the temperature rises of the + + + align:start position:0% +look at the temperature rises of the +thing you know the heat SN surface only + + align:start position:0% +thing you know the heat SN surface only + + + align:start position:0% +thing you know the heat SN surface only +goes up 20c why because we got crazy + + align:start position:0% +goes up 20c why because we got crazy + + + align:start position:0% +goes up 20c why because we got crazy +heat + + align:start position:0% +heat + + + align:start position:0% +heat +flow right so this is the kind of thing + + align:start position:0% +flow right so this is the kind of thing + + + align:start position:0% +flow right so this is the kind of thing +you do and we used exactly these models + + align:start position:0% +you do and we used exactly these models + + + align:start position:0% +you do and we used exactly these models +to essentially figure out what's the + + align:start position:0% +to essentially figure out what's the + + + align:start position:0% +to essentially figure out what's the +thermal resistance from The Junction to + + align:start position:0% +thermal resistance from The Junction to + + + align:start position:0% +thermal resistance from The Junction to +the case then we had the the case going + + align:start position:0% +the case then we had the the case going + + + align:start position:0% +the case then we had the the case going +down to the heat spreader and it was + + align:start position:0% +down to the heat spreader and it was + + + align:start position:0% +down to the heat spreader and it was +soldered so that's pretty low and the + + align:start position:0% +soldered so that's pretty low and the + + + align:start position:0% +soldered so that's pretty low and the +heat spreader to the heat sink and the + + align:start position:0% +heat spreader to the heat sink and the + + + align:start position:0% +heat spreader to the heat sink and the +heat sink to ambient we looked up from + + align:start position:0% +heat sink to ambient we looked up from + + + align:start position:0% +heat sink to ambient we looked up from +the data sheet and boom we have our + + align:start position:0% +the data sheet and boom we have our + + + align:start position:0% +the data sheet and boom we have our +model and we have our nice thing where + + align:start position:0% +model and we have our nice thing where + + + align:start position:0% +model and we have our nice thing where +we can pour lots of dissipated power + + align:start position:0% +we can pour lots of dissipated power + + + align:start position:0% +we can pour lots of dissipated power +into it and still keep it + + align:start position:0% +into it and still keep it + + + align:start position:0% +into it and still keep it +cool okay so I'm out of time are there + + align:start position:0% +cool okay so I'm out of time are there + + + align:start position:0% +cool okay so I'm out of time are there +any final questions uh will these slides + + align:start position:0% +any final questions uh will these slides + + + align:start position:0% +any final questions uh will these slides +be posted uh yeah we can put up these + + align:start position:0% +be posted uh yeah we can put up these + + + align:start position:0% +be posted uh yeah we can put up these +slides yep so this um yeah I'm just what + + align:start position:0% +slides yep so this um yeah I'm just what + + + align:start position:0% +slides yep so this um yeah I'm just what +the device what the it was a uh Gan + + align:start position:0% +the device what the it was a uh Gan + + + align:start position:0% +the device what the it was a uh Gan +system there were four Gan systems Ganon + + align:start position:0% +system there were four Gan systems Ganon + + + align:start position:0% +system there were four Gan systems Ganon +silicon 650 volt + + align:start position:0% +silicon 650 volt + + + align:start position:0% +silicon 650 volt +transistors um so yeah that's sort of a + + align:start position:0% +transistors um so yeah that's sort of a + + + align:start position:0% +transistors um so yeah that's sort of a +lightning introduction to quick and + + align:start position:0% +lightning introduction to quick and + + + align:start position:0% +lightning introduction to quick and +dirty heat sinking + + align:start position:0% +dirty heat sinking + + + align:start position:0% +dirty heat sinking +uh I still encourage you to actually + + align:start position:0% +uh I still encourage you to actually + + + align:start position:0% +uh I still encourage you to actually +take much more sophisticated classes on + + align:start position:0% +take much more sophisticated classes on + + + align:start position:0% +take much more sophisticated classes on +heat transfer I'm not saying this + + align:start position:0% +heat transfer I'm not saying this + + + align:start position:0% +heat transfer I'm not saying this +replaces that but it's enough to get you + + align:start position:0% +replaces that but it's enough to get you + + + align:start position:0% +replaces that but it's enough to get you +to build some pretty cool stuff okay so + + align:start position:0% +to build some pretty cool stuff okay so + + + align:start position:0% +to build some pretty cool stuff okay so +next time we'll go back to talking more + + align:start position:0% +next time we'll go back to talking more + + + align:start position:0% +next time we'll go back to talking more +about circuits have a great day \ No newline at end of file diff --git a/wRHJjg9jBjA.txt b/wRHJjg9jBjA.txt new file mode 100644 index 0000000000000000000000000000000000000000..42407b6419f6c9e46b92d8d14ff4abc705a330e1 --- /dev/null +++ b/wRHJjg9jBjA.txt @@ -0,0 +1,12727 @@ +align:start position:0% + +foreign + + align:start position:0% + + + + align:start position:0% + +discussing + + align:start position:0% +discussing + + + align:start position:0% +discussing +quantitation + + align:start position:0% +quantitation + + + align:start position:0% +quantitation +of the free scalar field Theory + + align:start position:0% +of the free scalar field Theory + + + align:start position:0% +of the free scalar field Theory +and then we showed we showed that the + + align:start position:0% +and then we showed we showed that the + + + align:start position:0% +and then we showed we showed that the +excitations + + align:start position:0% +excitations + + + align:start position:0% +excitations +of that theory essentially give rise to + + align:start position:0% +of that theory essentially give rise to + + + align:start position:0% +of that theory essentially give rise to +um relativistic particles okay + + align:start position:0% +um relativistic particles okay + + + align:start position:0% +um relativistic particles okay +and so we also discussed what is other + + align:start position:0% +and so we also discussed what is other + + + align:start position:0% +and so we also discussed what is other +things say here but structure of the + + align:start position:0% +things say here but structure of the + + + align:start position:0% +things say here but structure of the +healable space + + align:start position:0% +healable space + + + align:start position:0% +healable space +conserved quantities Etc + + align:start position:0% +conserved quantities Etc + + + align:start position:0% +conserved quantities Etc +so so + + align:start position:0% +so so + + + align:start position:0% +so so +at the end we talked about the um + + align:start position:0% +at the end we talked about the um + + + align:start position:0% +at the end we talked about the um +how to understand the + + align:start position:0% +how to understand the + + + align:start position:0% +how to understand the +um + + align:start position:0% +um + + + align:start position:0% +um +the conserved charges + + align:start position:0% + + + + align:start position:0% + +right the quantum level + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so classically + + align:start position:0% +so classically + + + align:start position:0% +so classically +so we we have a say symmetric + + align:start position:0% +so we we have a say symmetric + + + align:start position:0% +so we we have a say symmetric +transformation means that if you + + align:start position:0% +transformation means that if you + + + align:start position:0% +transformation means that if you +take Phi a to some Phi a prime okay if I + + align:start position:0% +take Phi a to some Phi a prime okay if I + + + align:start position:0% +take Phi a to some Phi a prime okay if I +have Prime + + align:start position:0% +have Prime + + + align:start position:0% +have Prime +normally we write it in the infinity + + align:start position:0% +normally we write it in the infinity + + + align:start position:0% +normally we write it in the infinity +decimal way + + align:start position:0% +decimal way + + + align:start position:0% +decimal way +introduce some parameter a some + + align:start position:0% +introduce some parameter a some + + + align:start position:0% +introduce some parameter a some +parameter Epsilon + + align:start position:0% +parameter Epsilon + + + align:start position:0% +parameter Epsilon +and I can also have multiple symmetries + + align:start position:0% +and I can also have multiple symmetries + + + align:start position:0% +and I can also have multiple symmetries +so for each transformation say I have a + + align:start position:0% +so for each transformation say I have a + + + align:start position:0% +so for each transformation say I have a +Epsilon so Alpha labels different + + align:start position:0% +Epsilon so Alpha labels different + + + align:start position:0% +Epsilon so Alpha labels different +transformations + + align:start position:0% +transformations + + + align:start position:0% +transformations +and then + + align:start position:0% +and then + + + align:start position:0% +and then +and then so this is the transformation + + align:start position:0% +and then so this is the transformation + + + align:start position:0% +and then so this is the transformation +which can depend on Phi a also depend on + + align:start position:0% +which can depend on Phi a also depend on + + + align:start position:0% +which can depend on Phi a also depend on +its derivatives Etc + + align:start position:0% + + + + align:start position:0% + +and then so if you have a sagio + + align:start position:0% +and then so if you have a sagio + + + align:start position:0% +and then so if you have a sagio +symmetric transformation we discussed + + align:start position:0% +symmetric transformation we discussed + + + align:start position:0% +symmetric transformation we discussed +before then that generates a conserved + + align:start position:0% +before then that generates a conserved + + + align:start position:0% +before then that generates a conserved +current + + align:start position:0% +current + + + align:start position:0% +current +and it is labeled by alpha alpha just + + align:start position:0% +and it is labeled by alpha alpha just + + + align:start position:0% +and it is labeled by alpha alpha just +the loads different conserved currents + + align:start position:0% +the loads different conserved currents + + + align:start position:0% +the loads different conserved currents +and then yeah so so it is conserved + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so this is the classical statement + + align:start position:0% +so this is the classical statement + + + align:start position:0% +so this is the classical statement +oh yeah also lots of theorem tells us + + align:start position:0% +oh yeah also lots of theorem tells us + + + align:start position:0% +oh yeah also lots of theorem tells us +how to write down such a current + + align:start position:0% +how to write down such a current + + + align:start position:0% +how to write down such a current +explicitly + + align:start position:0% + + + + align:start position:0% + +so we can just write it as + + align:start position:0% +so we can just write it as + + + align:start position:0% +so we can just write it as +the current can be written explicitly + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% + + + + align:start position:0% + +okay so K mu is the um + + align:start position:0% +okay so K mu is the um + + + align:start position:0% +okay so K mu is the um +the transformation of the lagrangian + + align:start position:0% +the transformation of the lagrangian + + + align:start position:0% +the transformation of the lagrangian +density + + align:start position:0% +density + + + align:start position:0% +density +suppose under this transformation the + + align:start position:0% +suppose under this transformation the + + + align:start position:0% +suppose under this transformation the +LaGrange density transform as + + align:start position:0% +LaGrange density transform as + + + align:start position:0% +LaGrange density transform as +say Alpha partial mu + + align:start position:0% +say Alpha partial mu + + + align:start position:0% +say Alpha partial mu +okay Mu Alpha okay + + align:start position:0% +okay Mu Alpha okay + + + align:start position:0% +okay Mu Alpha okay +so R5 doesn't matter Alpha just label + + align:start position:0% +so R5 doesn't matter Alpha just label + + + align:start position:0% +so R5 doesn't matter Alpha just label +different symmetries the the index + + align:start position:0% +different symmetries the the index + + + align:start position:0% +different symmetries the the index +doesn't matter whether it's up up or + + align:start position:0% +doesn't matter whether it's up up or + + + align:start position:0% +doesn't matter whether it's up up or +down okay + + align:start position:0% +down okay + + + align:start position:0% +down okay +and then + + align:start position:0% +and then + + + align:start position:0% +and then +then the zeros component + + align:start position:0% +then the zeros component + + + align:start position:0% +then the zeros component +of the charge this component of the + + align:start position:0% +of the charge this component of the + + + align:start position:0% +of the charge this component of the +current when you integrate of all space + + align:start position:0% +current when you integrate of all space + + + align:start position:0% +current when you integrate of all space +then give rise to a conserved charge + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and the + + align:start position:0% +and the + + + align:start position:0% +and the +um yeah + + align:start position:0% +um yeah + + + align:start position:0% +um yeah +so now let's discuss + + align:start position:0% + + + + align:start position:0% + +so when you go to Quantum level so when + + align:start position:0% +so when you go to Quantum level so when + + + align:start position:0% +so when you go to Quantum level so when +you quantize the theory + + align:start position:0% +you quantize the theory + + + align:start position:0% +you quantize the theory +and this just become Quantum operator + + align:start position:0% +and this just become Quantum operator + + + align:start position:0% +and this just become Quantum operator +and yeah the whole current become a + + align:start position:0% +and yeah the whole current become a + + + align:start position:0% +and yeah the whole current become a +Quantum operator + + align:start position:0% +Quantum operator + + + align:start position:0% +Quantum operator +and then Q is also a Quantum operator + + align:start position:0% +and then Q is also a Quantum operator + + + align:start position:0% +and then Q is also a Quantum operator +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so the quantum level + + align:start position:0% + + + + align:start position:0% + +and Quantum level and the null Q Alpha + + align:start position:0% +and Quantum level and the null Q Alpha + + + align:start position:0% +and Quantum level and the null Q Alpha +because it's conserved + + align:start position:0% +because it's conserved + + + align:start position:0% +because it's conserved +so this becomes time independent + + align:start position:0% +so this becomes time independent + + + align:start position:0% +so this becomes time independent +operator + + align:start position:0% + + + + align:start position:0% + +receipt + + align:start position:0% + + + + align:start position:0% + +we see the explicit tree in the case of + + align:start position:0% +we see the explicit tree in the case of + + + align:start position:0% +we see the explicit tree in the case of +the say hamiltonian density hamiltonian + + align:start position:0% +the say hamiltonian density hamiltonian + + + align:start position:0% +the say hamiltonian density hamiltonian +and the momentum okay so we show the + + align:start position:0% +and the momentum okay so we show the + + + align:start position:0% +and the momentum okay so we show the +explicitly they they actually don't + + align:start position:0% +explicitly they they actually don't + + + align:start position:0% +explicitly they they actually don't +depend on time + + align:start position:0% +depend on time + + + align:start position:0% +depend on time +but at the quantum mechanical level + + align:start position:0% +but at the quantum mechanical level + + + align:start position:0% +but at the quantum mechanical level +actually this Q can play a more + + align:start position:0% +actually this Q can play a more + + + align:start position:0% +actually this Q can play a more +important role + + align:start position:0% +important role + + + align:start position:0% +important role +uh can play more importantly in fact it + + align:start position:0% +uh can play more importantly in fact it + + + align:start position:0% +uh can play more importantly in fact it +can be viewed as a generator of + + align:start position:0% +can be viewed as a generator of + + + align:start position:0% +can be viewed as a generator of +symmetries okay so we can show + + align:start position:0% + + + + align:start position:0% + +we will show the following statement + + align:start position:0% +we will show the following statement + + + align:start position:0% +we will show the following statement +that if you consider + + align:start position:0% +that if you consider + + + align:start position:0% +that if you consider +the Epsilon so so consider such a + + align:start position:0% +the Epsilon so so consider such a + + + align:start position:0% +the Epsilon so so consider such a +quantity + + align:start position:0% +quantity + + + align:start position:0% +quantity +yeah uh + + align:start position:0% +yeah uh + + + align:start position:0% +yeah uh +can you see the commutative Q + + align:start position:0% +can you see the commutative Q + + + align:start position:0% +can you see the commutative Q +with 5A + + align:start position:0% +with 5A + + + align:start position:0% +with 5A +okay + + align:start position:0% + + + + align:start position:0% + +so now let's continue over to here + + align:start position:0% + + + + align:start position:0% + +yeah maybe just let me write it here and + + align:start position:0% +yeah maybe just let me write it here and + + + align:start position:0% +yeah maybe just let me write it here and +that generate minus Epsilon Alpha + + align:start position:0% +that generate minus Epsilon Alpha + + + align:start position:0% +that generate minus Epsilon Alpha +F Alpha a + + align:start position:0% +F Alpha a + + + align:start position:0% +F Alpha a +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so the commutator + + align:start position:0% + + + + align:start position:0% + +a essentially generate this + + align:start position:0% +a essentially generate this + + + align:start position:0% +a essentially generate this +transformation + + align:start position:0% +transformation + + + align:start position:0% +transformation +okay essentially generate this + + align:start position:0% +okay essentially generate this + + + align:start position:0% +okay essentially generate this +infinitesimal transformation + + align:start position:0% + + + + align:start position:0% + +um + + align:start position:0% +um + + + align:start position:0% +um +so that's why we call the Q Alpha also a + + align:start position:0% +so that's why we call the Q Alpha also a + + + align:start position:0% +so that's why we call the Q Alpha also a +generator of symmetries okay + + align:start position:0% + + + + align:start position:0% + +so so this is the statement that I'm + + align:start position:0% +so so this is the statement that I'm + + + align:start position:0% +so so this is the statement that I'm +going to show very soon okay so before I + + align:start position:0% +going to show very soon okay so before I + + + align:start position:0% +going to show very soon okay so before I +do that you have any questions + + align:start position:0% +do that you have any questions + + + align:start position:0% +do that you have any questions +yes + + align:start position:0% +yes + + + align:start position:0% +yes +current equation how can have been + + align:start position:0% +current equation how can have been + + + align:start position:0% +current equation how can have been +helpful in the upper index like Jay + + align:start position:0% +helpful in the upper index like Jay + + + align:start position:0% +helpful in the upper index like Jay +hasn't happened lower either and it's + + align:start position:0% +hasn't happened lower either and it's + + + align:start position:0% +hasn't happened lower either and it's +not me yeah yeah just offer don't worry + + align:start position:0% +not me yeah yeah just offer don't worry + + + align:start position:0% +not me yeah yeah just offer don't worry +about the location of alpha index Alpha + + align:start position:0% +about the location of alpha index Alpha + + + align:start position:0% +about the location of alpha index Alpha +just label a different current + + align:start position:0% +just label a different current + + + align:start position:0% +just label a different current +and just one yeah it yeah here we don't + + align:start position:0% +and just one yeah it yeah here we don't + + + align:start position:0% +and just one yeah it yeah here we don't +worry about its location yeah I just put + + align:start position:0% +worry about its location yeah I just put + + + align:start position:0% +worry about its location yeah I just put +it up and down just for uh for + + align:start position:0% +it up and down just for uh for + + + align:start position:0% +it up and down just for uh for +convenience + + align:start position:0% + + + + align:start position:0% + +other questions + + align:start position:0% +other questions + + + align:start position:0% +other questions +yes sorry + + align:start position:0% + + + + align:start position:0% + +yeah there's some of all of us so let me + + align:start position:0% +yeah there's some of all of us so let me + + + align:start position:0% +yeah there's some of all of us so let me +repeat this indices is sound okay so if + + align:start position:0% +repeat this indices is sound okay so if + + + align:start position:0% +repeat this indices is sound okay so if +you only have one + + align:start position:0% +you only have one + + + align:start position:0% +you only have one +say for example if you have yeah one + + align:start position:0% +say for example if you have yeah one + + + align:start position:0% +say for example if you have yeah one +absolute of course there's no sound but + + align:start position:0% +absolute of course there's no sound but + + + align:start position:0% +absolute of course there's no sound but +if you have two different charges uh and + + align:start position:0% +if you have two different charges uh and + + + align:start position:0% +if you have two different charges uh and +then yeah this is some + + align:start position:0% + + + + align:start position:0% + +other questions + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so um + + align:start position:0% +so um + + + align:start position:0% +so um +so we are going to show this statement + + align:start position:0% +so we are going to show this statement + + + align:start position:0% +so we are going to show this statement +and so this statement is very easy to + + align:start position:0% +and so this statement is very easy to + + + align:start position:0% +and so this statement is very easy to +show in the in the general case + + align:start position:0% + + + + align:start position:0% + +um so let me call this equation star + + align:start position:0% +um so let me call this equation star + + + align:start position:0% +um so let me call this equation star +so let's first consider the case + + align:start position:0% +so let's first consider the case + + + align:start position:0% +so let's first consider the case +versus consider the sub case + + align:start position:0% +versus consider the sub case + + + align:start position:0% +versus consider the sub case +that the + + align:start position:0% +that the + + + align:start position:0% +that the +um + + align:start position:0% + + + + align:start position:0% + +let's first suppose + + align:start position:0% + + + + align:start position:0% + +far just this transformation + + align:start position:0% +far just this transformation + + + align:start position:0% +far just this transformation +okay I'll find a + + align:start position:0% +okay I'll find a + + + align:start position:0% +okay I'll find a +does not contain + + align:start position:0% + + + + align:start position:0% + +the time derivative of a okay + + align:start position:0% +the time derivative of a okay + + + align:start position:0% +the time derivative of a okay +and also + + align:start position:0% +and also + + + align:start position:0% +and also +the the zeros component of the K is + + align:start position:0% +the the zeros component of the K is + + + align:start position:0% +the the zeros component of the K is +equal to zero okay + + align:start position:0% +equal to zero okay + + + align:start position:0% +equal to zero okay +so let's consider a a a first special + + align:start position:0% + + + + align:start position:0% + +a more limited case + + align:start position:0% +a more limited case + + + align:start position:0% +a more limited case +okay so this + + align:start position:0% + + + + align:start position:0% + +so this is the more limited case + + align:start position:0% +so this is the more limited case + + + align:start position:0% +so this is the more limited case +actually covers many many examples okay + + align:start position:0% +actually covers many many examples okay + + + align:start position:0% +actually covers many many examples okay +I actually covers a majority of examples + + align:start position:0% +I actually covers a majority of examples + + + align:start position:0% +I actually covers a majority of examples +for example if you look at the of + + align:start position:0% +for example if you look at the of + + + align:start position:0% +for example if you look at the of +translation symmetry which give rise to + + align:start position:0% +translation symmetry which give rise to + + + align:start position:0% +translation symmetry which give rise to +the stress sensor so so this will so + + align:start position:0% +the stress sensor so so this will so + + + align:start position:0% +the stress sensor so so this will so +this applies to the case I mu + + align:start position:0% +this applies to the case I mu + + + align:start position:0% +this applies to the case I mu +team UI so + + align:start position:0% +team UI so + + + align:start position:0% +team UI so +so this corresponding to the spatial + + align:start position:0% +so this corresponding to the spatial + + + align:start position:0% +so this corresponding to the spatial +so this is the conserved current + + align:start position:0% +so this is the conserved current + + + align:start position:0% +so this is the conserved current +corresponding to the spatial + + align:start position:0% +corresponding to the spatial + + + align:start position:0% +corresponding to the spatial +so this is the current + + align:start position:0% + + + + align:start position:0% + +for spatial translations + + align:start position:0% + + + + align:start position:0% + +for spatial translations + + align:start position:0% +for spatial translations + + + align:start position:0% +for spatial translations +and of course this uh this uh F gets + + align:start position:0% +and of course this uh this uh F gets + + + align:start position:0% +and of course this uh this uh F gets +given by the spatial derivatives + + align:start position:0% +given by the spatial derivatives + + + align:start position:0% +given by the spatial derivatives +and then it does not involve time + + align:start position:0% +and then it does not involve time + + + align:start position:0% +and then it does not involve time +derivative + + align:start position:0% +derivative + + + align:start position:0% +derivative +and in that case the uh K also does not + + align:start position:0% +and in that case the uh K also does not + + + align:start position:0% +and in that case the uh K also does not +involve in a k0 component zero yeah just + + align:start position:0% +involve in a k0 component zero yeah just + + + align:start position:0% +involve in a k0 component zero yeah just +I try to remind myself which you worked + + align:start position:0% +I try to remind myself which you worked + + + align:start position:0% +I try to remind myself which you worked +in your PSAT + + align:start position:0% +in your PSAT + + + align:start position:0% +in your PSAT +and so so for this example + + align:start position:0% +and so so for this example + + + align:start position:0% +and so so for this example +I + + align:start position:0% +I + + + align:start position:0% +I +is the counterpart is the alpha here + + align:start position:0% +is the counterpart is the alpha here + + + align:start position:0% +is the counterpart is the alpha here +okay so for each Direction + + align:start position:0% +okay so for each Direction + + + align:start position:0% +okay so for each Direction +you have a translation and so this uh so + + align:start position:0% +you have a translation and so this uh so + + + align:start position:0% +you have a translation and so this uh so +the alpha of course s i is the alpha + + align:start position:0% +the alpha of course s i is the alpha + + + align:start position:0% +the alpha of course s i is the alpha +here and the MU is the JMU here okay + + align:start position:0% + + + + align:start position:0% + +and and also + + align:start position:0% +and and also + + + align:start position:0% +and and also +this applies to the case which uh + + align:start position:0% +this applies to the case which uh + + + align:start position:0% +this applies to the case which uh +for all + + align:start position:0% + + + + align:start position:0% + +internal symmetries + + align:start position:0% + + + + align:start position:0% + +now internal symmetries we mean the + + align:start position:0% +now internal symmetries we mean the + + + align:start position:0% +now internal symmetries we mean the +Transformations don't involve space-time + + align:start position:0% +Transformations don't involve space-time + + + align:start position:0% +Transformations don't involve space-time +coordinates + + align:start position:0% +coordinates + + + align:start position:0% +coordinates +okay for example you uh you did in your + + align:start position:0% +okay for example you uh you did in your + + + align:start position:0% +okay for example you uh you did in your +piece that the complex scalar field + + align:start position:0% +piece that the complex scalar field + + + align:start position:0% +piece that the complex scalar field +which you can just rotate the bear face + + align:start position:0% +which you can just rotate the bear face + + + align:start position:0% +which you can just rotate the bear face +and that's called the internal + + align:start position:0% +and that's called the internal + + + align:start position:0% +and that's called the internal +transmission because that transformation + + align:start position:0% +transmission because that transformation + + + align:start position:0% +transmission because that transformation +doesn't does not involve uh um + + align:start position:0% +doesn't does not involve uh um + + + align:start position:0% +doesn't does not involve uh um +space-time coordinates in contrast when + + align:start position:0% +space-time coordinates in contrast when + + + align:start position:0% +space-time coordinates in contrast when +we find the stress sensor we we will do + + align:start position:0% +we find the stress sensor we we will do + + + align:start position:0% +we find the stress sensor we we will do +a space-time translation and that does + + align:start position:0% +a space-time translation and that does + + + align:start position:0% +a space-time translation and that does +involve space-time transform yeah so so + + align:start position:0% +involve space-time transform yeah so so + + + align:start position:0% +involve space-time transform yeah so so +this corresponding to the space-time + + align:start position:0% +this corresponding to the space-time + + + align:start position:0% +this corresponding to the space-time +Transformations space time symmetries + + align:start position:0% +Transformations space time symmetries + + + align:start position:0% +Transformations space time symmetries +and this is the phase is the internal + + align:start position:0% +and this is the phase is the internal + + + align:start position:0% +and this is the phase is the internal +symmetries okay so for all internal + + align:start position:0% +symmetries okay so for all internal + + + align:start position:0% +symmetries okay so for all internal +symmetries + + align:start position:0% +symmetries + + + align:start position:0% +symmetries +you don't the the transmission will not + + align:start position:0% +you don't the the transmission will not + + + align:start position:0% +you don't the the transmission will not +contain the time derivative + + align:start position:0% + + + + align:start position:0% + +so so in this case then then it's easy + + align:start position:0% + + + + align:start position:0% + +because in this case then we just have + + align:start position:0% +because in this case then we just have + + + align:start position:0% +because in this case then we just have +the one then the zeros component of J mu + + align:start position:0% +the one then the zeros component of J mu + + + align:start position:0% +the one then the zeros component of J mu +j h is given by + + align:start position:0% +j h is given by + + + align:start position:0% +j h is given by +the first term by definition is just the + + align:start position:0% +the first term by definition is just the + + + align:start position:0% +the first term by definition is just the +canonical momentum + + align:start position:0% +canonical momentum + + + align:start position:0% +canonical momentum +conjugate to the um + + align:start position:0% +conjugate to the um + + + align:start position:0% +conjugate to the um +to the A + + align:start position:0% +to the A + + + align:start position:0% +to the A +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so the the first Factor part of L + + align:start position:0% +so the the first Factor part of L + + + align:start position:0% +so the the first Factor part of L +partial python view Phi a when you set + + align:start position:0% +partial python view Phi a when you set + + + align:start position:0% +partial python view Phi a when you set +mu equal to zero so that's just the + + align:start position:0% +mu equal to zero so that's just the + + + align:start position:0% +mu equal to zero so that's just the +derivative respect to the time + + align:start position:0% +derivative respect to the time + + + align:start position:0% +derivative respect to the time +derivative of Phi a and that by + + align:start position:0% +derivative of Phi a and that by + + + align:start position:0% +derivative of Phi a and that by +definition is just the + + align:start position:0% +definition is just the + + + align:start position:0% +definition is just the +um the canonical momentum density + + align:start position:0% +um the canonical momentum density + + + align:start position:0% +um the canonical momentum density +conjugate to Phi a + + align:start position:0% +conjugate to Phi a + + + align:start position:0% +conjugate to Phi a +and then then you have + + align:start position:0% +and then then you have + + + align:start position:0% +and then then you have +f + + align:start position:0% +f + + + align:start position:0% +f +Alpha a okay + + align:start position:0% +Alpha a okay + + + align:start position:0% +Alpha a okay +f a alpha + + align:start position:0% +f a alpha + + + align:start position:0% +f a alpha +okay + + align:start position:0% + + + + align:start position:0% + +good + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +so let me just make one + + align:start position:0% +so let me just make one + + + align:start position:0% +so let me just make one +comment on this because expression + + align:start position:0% +comment on this because expression + + + align:start position:0% +comment on this because expression +so this expression of course uh + + align:start position:0% +so this expression of course uh + + + align:start position:0% +so this expression of course uh +classically + + align:start position:0% +classically + + + align:start position:0% +classically +you can write whatever way you want + + align:start position:0% +you can write whatever way you want + + + align:start position:0% +you can write whatever way you want +but the quantum mechanical is this a + + align:start position:0% +but the quantum mechanical is this a + + + align:start position:0% +but the quantum mechanical is this a +very important subtlety + + align:start position:0% +very important subtlety + + + align:start position:0% +very important subtlety +because this typically will involve Phi + + align:start position:0% +because this typically will involve Phi + + + align:start position:0% +because this typically will involve Phi +okay and and then this is momentum and + + align:start position:0% +okay and and then this is momentum and + + + align:start position:0% +okay and and then this is momentum and +they don't necessarily compute so this + + align:start position:0% +they don't necessarily compute so this + + + align:start position:0% +they don't necessarily compute so this +is the the field three version of + + align:start position:0% +is the the field three version of + + + align:start position:0% +is the the field three version of +so-called the uh operate ordinary + + align:start position:0% +so-called the uh operate ordinary + + + align:start position:0% +so-called the uh operate ordinary +ambiguity which you Authority in quantum + + align:start position:0% +ambiguity which you Authority in quantum + + + align:start position:0% +ambiguity which you Authority in quantum +mechanics okay in quantum mechanics when + + align:start position:0% +mechanics okay in quantum mechanics when + + + align:start position:0% +mechanics okay in quantum mechanics when +you go from classical book + + align:start position:0% +you go from classical book + + + align:start position:0% +you go from classical book +even it's already in the long right + + align:start position:0% +even it's already in the long right + + + align:start position:0% +even it's already in the long right +basic Quantum mechanism when you go to + + align:start position:0% +basic Quantum mechanism when you go to + + + align:start position:0% +basic Quantum mechanism when you go to +classical mechanics to quantum mechanics + + align:start position:0% +classical mechanics to quantum mechanics + + + align:start position:0% +classical mechanics to quantum mechanics +and then there's an issue how you order + + align:start position:0% +and then there's an issue how you order + + + align:start position:0% +and then there's an issue how you order +uh operators when you have X and the P + + align:start position:0% +uh operators when you have X and the P + + + align:start position:0% +uh operators when you have X and the P +at the same time okay so here you also + + align:start position:0% +at the same time okay so here you also + + + align:start position:0% +at the same time okay so here you also +have potential + + align:start position:0% + + + + align:start position:0% + +uh operate I'm ordering ambiguity + + align:start position:0% +uh operate I'm ordering ambiguity + + + align:start position:0% +uh operate I'm ordering ambiguity +you have to pay attention + + align:start position:0% + + + + align:start position:0% + +often such kind of ambiguities can be + + align:start position:0% +often such kind of ambiguities can be + + + align:start position:0% +often such kind of ambiguities can be +resolved by physical considerations okay + + align:start position:0% +resolved by physical considerations okay + + + align:start position:0% +resolved by physical considerations okay +so we will see some examples + + align:start position:0% +so we will see some examples + + + align:start position:0% +so we will see some examples +in a little bit okay + + align:start position:0% + + + + align:start position:0% + +so so now let's just imagine there's + + align:start position:0% +so so now let's just imagine there's + + + align:start position:0% +so so now let's just imagine there's +some ordering we have chosen + + align:start position:0% +some ordering we have chosen + + + align:start position:0% +some ordering we have chosen +and now let's look at this commentator + + align:start position:0% + + + + align:start position:0% + +okay so so we can just write down the + + align:start position:0% +okay so so we can just write down the + + + align:start position:0% +okay so so we can just write down the +definition + + align:start position:0% +definition + + + align:start position:0% +definition +so this is just integrating mobile or + + align:start position:0% +so this is just integrating mobile or + + + align:start position:0% +so this is just integrating mobile or +spatial movement a special Direction + + align:start position:0% +spatial movement a special Direction + + + align:start position:0% +spatial movement a special Direction +Epsilon Alpha + + align:start position:0% +Epsilon Alpha + + + align:start position:0% +Epsilon Alpha +and then we have Pi a + + align:start position:0% +and then we have Pi a + + + align:start position:0% +and then we have Pi a +f a alpha 5A + + align:start position:0% +f a alpha 5A + + + align:start position:0% +f a alpha 5A +yeah let me just + + align:start position:0% +yeah let me just + + + align:start position:0% +yeah let me just +sorry here let me call 5B because the 5A + + align:start position:0% +sorry here let me call 5B because the 5A + + + align:start position:0% +sorry here let me call 5B because the 5A +now they are different so these two + + align:start position:0% +now they are different so these two + + + align:start position:0% +now they are different so these two +indices are sound okay so so like let me + + align:start position:0% +indices are sound okay so so like let me + + + align:start position:0% +indices are sound okay so so like let me +call them B and then you have five a + + align:start position:0% +call them B and then you have five a + + + align:start position:0% +call them B and then you have five a +here okay + + align:start position:0% +here okay + + + align:start position:0% +here okay +so now you can use a commutation + + align:start position:0% +so now you can use a commutation + + + align:start position:0% +so now you can use a commutation +relation uh between the uh a momentum + + align:start position:0% +relation uh between the uh a momentum + + + align:start position:0% +relation uh between the uh a momentum +density and the Phi Phi so + + align:start position:0% +density and the Phi Phi so + + + align:start position:0% +density and the Phi Phi so +so we discussed in general that the + + align:start position:0% +so we discussed in general that the + + + align:start position:0% +so we discussed in general that the +so we discussed the scalar case but in + + align:start position:0% +so we discussed the scalar case but in + + + align:start position:0% +so we discussed the scalar case but in +general you have this commutation + + align:start position:0% +general you have this commutation + + + align:start position:0% +general you have this commutation +relation + + align:start position:0% +relation + + + align:start position:0% +relation +uh + + align:start position:0% +uh + + + align:start position:0% +uh +which is Delta + + align:start position:0% +which is Delta + + + align:start position:0% +which is Delta +three + + align:start position:0% +three + + + align:start position:0% +three +say if this is the X + + align:start position:0% +say if this is the X + + + align:start position:0% +say if this is the X +and this is X Prime + + align:start position:0% +and this is X Prime + + + align:start position:0% +and this is X Prime +and then this is x minus X Prime okay + + align:start position:0% +and then this is x minus X Prime okay + + + align:start position:0% +and then this is x minus X Prime okay +and Delta a b okay so so each one is + + align:start position:0% +and Delta a b okay so so each one is + + + align:start position:0% +and Delta a b okay so so each one is +only uh have come a canonical conjugate + + align:start position:0% +only uh have come a canonical conjugate + + + align:start position:0% +only uh have come a canonical conjugate +momentum with its own momentum okay if + + align:start position:0% +momentum with its own momentum okay if + + + align:start position:0% +momentum with its own momentum okay if +they have different fields then of + + align:start position:0% +they have different fields then of + + + align:start position:0% +they have different fields then of +course yeah so um yeah you have that and + + align:start position:0% +course yeah so um yeah you have that and + + + align:start position:0% +course yeah so um yeah you have that and +now if you use this okay so so here is X + + align:start position:0% +now if you use this okay so so here is X + + + align:start position:0% +now if you use this okay so so here is X +yeah let me call this Prime and this to + + align:start position:0% +yeah let me call this Prime and this to + + + align:start position:0% +yeah let me call this Prime and this to +be X + + align:start position:0% +be X + + + align:start position:0% +be X +okay sorry uh + + align:start position:0% +okay sorry uh + + + align:start position:0% +okay sorry uh +should I should label more explicitly X + + align:start position:0% +should I should label more explicitly X + + + align:start position:0% +should I should label more explicitly X +here and then here will be X okay + + align:start position:0% +here and then here will be X okay + + + align:start position:0% +here and then here will be X okay +and so so here is X and here will be X + + align:start position:0% +and so so here is X and here will be X + + + align:start position:0% +and so so here is X and here will be X +Prime + + align:start position:0% +Prime + + + align:start position:0% +Prime +sorry I I didn't leave myself enough + + align:start position:0% +sorry I I didn't leave myself enough + + + align:start position:0% +sorry I I didn't leave myself enough +space let me just rewrite it + + align:start position:0% + + + + align:start position:0% + +so this gives me D3 X Prime + + align:start position:0% +so this gives me D3 X Prime + + + align:start position:0% +so this gives me D3 X Prime +Epsilon Alpha + + align:start position:0% +Epsilon Alpha + + + align:start position:0% +Epsilon Alpha +then I will have this uh + + align:start position:0% +then I will have this uh + + + align:start position:0% +then I will have this uh +um Pi a + + align:start position:0% +um Pi a + + + align:start position:0% +um Pi a +then X Prime + + align:start position:0% +then X Prime + + + align:start position:0% +then X Prime +F Alpha + + align:start position:0% +F Alpha + + + align:start position:0% +F Alpha +a + + align:start position:0% +a + + + align:start position:0% +a +X Prime + + align:start position:0% +X Prime + + + align:start position:0% +X Prime +and then V is commutated with + + align:start position:0% +and then V is commutated with + + + align:start position:0% +and then V is commutated with +yeah not copy sorry Alpha is down + + align:start position:0% +yeah not copy sorry Alpha is down + + + align:start position:0% +yeah not copy sorry Alpha is down +upstairs + + align:start position:0% +upstairs + + + align:start position:0% +upstairs +B and then five x okay + + align:start position:0% +B and then five x okay + + + align:start position:0% +B and then five x okay +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and uh + + align:start position:0% +and uh + + + align:start position:0% +and uh +yeah so we can evaluate this say for + + align:start position:0% +yeah so we can evaluate this say for + + + align:start position:0% +yeah so we can evaluate this say for +example or Olt equal to zero so I + + align:start position:0% +example or Olt equal to zero so I + + + align:start position:0% +example or Olt equal to zero so I +suppress the T + + align:start position:0% +suppress the T + + + align:start position:0% +suppress the T +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and then + + align:start position:0% +and then + + + align:start position:0% +and then +um yeah and now you can just trivially + + align:start position:0% +um yeah and now you can just trivially + + + align:start position:0% +um yeah and now you can just trivially +use this computation relation + + align:start position:0% +use this computation relation + + + align:start position:0% +use this computation relation +and and then this just gives you minus I + + align:start position:0% +and and then this just gives you minus I + + + align:start position:0% +and and then this just gives you minus I +Epsilon Alpha F Alpha a + + align:start position:0% +Epsilon Alpha F Alpha a + + + align:start position:0% +Epsilon Alpha F Alpha a +f a alpha + + align:start position:0% +f a alpha + + + align:start position:0% +f a alpha +X okay evaluate at X okay + + align:start position:0% + + + + align:start position:0% + +so so that just confirmed a confirms + + align:start position:0% +so so that just confirmed a confirms + + + align:start position:0% +so so that just confirmed a confirms +that expression okay + + align:start position:0% +that expression okay + + + align:start position:0% +that expression okay +for mixed extraction + + align:start position:0% +for mixed extraction + + + align:start position:0% +for mixed extraction +so this is not satisfied + + align:start position:0% +so this is not satisfied + + + align:start position:0% +so this is not satisfied +when you have time translation okay + + align:start position:0% +when you have time translation okay + + + align:start position:0% +when you have time translation okay +so for time translation + + align:start position:0% +so for time translation + + + align:start position:0% +so for time translation +so first any questions on this + + align:start position:0% +so first any questions on this + + + align:start position:0% +so first any questions on this +in this simple case yeah the idea is + + align:start position:0% +in this simple case yeah the idea is + + + align:start position:0% +in this simple case yeah the idea is +very simple it essentially just the + + align:start position:0% +very simple it essentially just the + + + align:start position:0% +very simple it essentially just the +first term proponent to the momentum and + + align:start position:0% +first term proponent to the momentum and + + + align:start position:0% +first term proponent to the momentum and +the momentum uh uh uh uh conjugate to + + align:start position:0% +the momentum uh uh uh uh conjugate to + + + align:start position:0% +the momentum uh uh uh uh conjugate to +this and then you just take that okay + + align:start position:0% +this and then you just take that okay + + + align:start position:0% +this and then you just take that okay +yes + + align:start position:0% + + + + align:start position:0% + +that's right that's right yeah so so if + + align:start position:0% +that's right that's right yeah so so if + + + align:start position:0% +that's right that's right yeah so so if +there's no partial zero there's no time + + align:start position:0% +there's no partial zero there's no time + + + align:start position:0% +there's no partial zero there's no time +due to here means there's no momentum + + align:start position:0% +due to here means there's no momentum + + + align:start position:0% +due to here means there's no momentum +here right if there's no momentum here + + align:start position:0% +here right if there's no momentum here + + + align:start position:0% +here right if there's no momentum here +then this will commute with this one + + align:start position:0% +then this will commute with this one + + + align:start position:0% +then this will commute with this one +yeah no matter is in here it's always + + align:start position:0% +yeah no matter is in here it's always + + + align:start position:0% +yeah no matter is in here it's always +compute yeah a very good question yeah I + + align:start position:0% +compute yeah a very good question yeah I + + + align:start position:0% +compute yeah a very good question yeah I +forgot to mention this point yeah + + align:start position:0% +forgot to mention this point yeah + + + align:start position:0% +forgot to mention this point yeah +other questions + + align:start position:0% + + + + align:start position:0% + +okay good + + align:start position:0% +okay good + + + align:start position:0% +okay good +so + + align:start position:0% +so + + + align:start position:0% +so +so now + + align:start position:0% + + + + align:start position:0% + +the special case + + align:start position:0% +the special case + + + align:start position:0% +the special case +he said if you have time translation + + align:start position:0% + + + + align:start position:0% + +okay when you have time translation + + align:start position:0% +okay when you have time translation + + + align:start position:0% +okay when you have time translation +for example a one example is the + + align:start position:0% +for example a one example is the + + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +um + + align:start position:0% +um + + + align:start position:0% +um +yeah uh the the the hamiltonian density + + align:start position:0% +yeah uh the the the hamiltonian density + + + align:start position:0% +yeah uh the the the hamiltonian density +H is equal to Pi a + + align:start position:0% +H is equal to Pi a + + + align:start position:0% +H is equal to Pi a +part of T by a minus L okay so the L + + align:start position:0% +part of T by a minus L okay so the L + + + align:start position:0% +part of T by a minus L okay so the L +here for the time translation L is the + + align:start position:0% +here for the time translation L is the + + + align:start position:0% +here for the time translation L is the +analog of K + + align:start position:0% + + + + align:start position:0% + +and the departure t5a is the F here + + align:start position:0% +and the departure t5a is the F here + + + align:start position:0% +and the departure t5a is the F here +and then here is the pay okay so so here + + align:start position:0% +and then here is the pay okay so so here + + + align:start position:0% +and then here is the pay okay so so here +you also have time derivative okay + + align:start position:0% + + + + align:start position:0% + +here you also have time divided and so + + align:start position:0% +here you also have time divided and so + + + align:start position:0% +here you also have time divided and so +this by itself is also a pi okay + + align:start position:0% +this by itself is also a pi okay + + + align:start position:0% +this by itself is also a pi okay +and the L + + align:start position:0% +and the L + + + align:start position:0% +and the L +uh may also contain time derivative + + align:start position:0% +uh may also contain time derivative + + + align:start position:0% +uh may also contain time derivative +so so L is the k0 here okay so so in + + align:start position:0% +so so L is the k0 here okay so so in + + + align:start position:0% +so so L is the k0 here okay so so in +this case the k0 is non-zero and which + + align:start position:0% +this case the k0 is non-zero and which + + + align:start position:0% +this case the k0 is non-zero and which +is equal to l + + align:start position:0% + + + + align:start position:0% + +and so in this case the conserved charge + + align:start position:0% +and so in this case the conserved charge + + + align:start position:0% +and so in this case the conserved charge +is just h + + align:start position:0% + + + + align:start position:0% + +so in this case you uh um + + align:start position:0% +so in this case you uh um + + + align:start position:0% +so in this case you uh um +our general argument here don't apply + + align:start position:0% +our general argument here don't apply + + + align:start position:0% +our general argument here don't apply +because now you have Pi here also and + + align:start position:0% +because now you have Pi here also and + + + align:start position:0% +because now you have Pi here also and +you may have a Time derivative here also + + align:start position:0% +you may have a Time derivative here also + + + align:start position:0% +you may have a Time derivative here also +okay so the story is more complicated + + align:start position:0% +okay so the story is more complicated + + + align:start position:0% +okay so the story is more complicated +but this case we load trivial is true + + align:start position:0% +but this case we load trivial is true + + + align:start position:0% +but this case we load trivial is true +because it's by definition + + align:start position:0% +because it's by definition + + + align:start position:0% +because it's by definition +h + + align:start position:0% +h + + + align:start position:0% +h +acting on any field + + align:start position:0% +acting on any field + + + align:start position:0% +acting on any field +okay + + align:start position:0% +okay + + + align:start position:0% +okay +is minus i r to T if i a + + align:start position:0% +is minus i r to T if i a + + + align:start position:0% +is minus i r to T if i a +and this is exactly the time translation + + align:start position:0% +and this is exactly the time translation + + + align:start position:0% +and this is exactly the time translation +a transformation of our fields + + align:start position:0% +a transformation of our fields + + + align:start position:0% +a transformation of our fields +okay so so in this special case + + align:start position:0% +okay so so in this special case + + + align:start position:0% +okay so so in this special case +this equation is also satisfied + + align:start position:0% + + + + align:start position:0% + +good any questions on this + + align:start position:0% + + + + align:start position:0% + +okay so so this is just followed from + + align:start position:0% +okay so so this is just followed from + + + align:start position:0% +okay so so this is just followed from +the Heisenberg equation itself okay and + + align:start position:0% +the Heisenberg equation itself okay and + + + align:start position:0% +the Heisenberg equation itself okay and +now you should just understand this + + align:start position:0% +now you should just understand this + + + align:start position:0% +now you should just understand this +equation + + align:start position:0% + + + + align:start position:0% + +as the age now can be considered as a + + align:start position:0% +as the age now can be considered as a + + + align:start position:0% +as the age now can be considered as a +symmetry generator for time translation + + align:start position:0% +symmetry generator for time translation + + + align:start position:0% +symmetry generator for time translation +symmetry + + align:start position:0% +symmetry + + + align:start position:0% +symmetry +and when it acts on the field and + + align:start position:0% +and when it acts on the field and + + + align:start position:0% +and when it acts on the field and +generate the time translation okay time + + align:start position:0% +generate the time translation okay time + + + align:start position:0% +generate the time translation okay time +translation just + + align:start position:0% +translation just + + + align:start position:0% +translation just +infinitesimally just to time derivative + + align:start position:0% +infinitesimally just to time derivative + + + align:start position:0% +infinitesimally just to time derivative +one Phi + + align:start position:0% + + + + align:start position:0% + +good + + align:start position:0% +good + + + align:start position:0% +good +so + + align:start position:0% +so + + + align:start position:0% +so +so these are infinitesimal + + align:start position:0% +so these are infinitesimal + + + align:start position:0% +so these are infinitesimal +transformations + + align:start position:0% +transformations + + + align:start position:0% +transformations +but now starting from here + + align:start position:0% +but now starting from here + + + align:start position:0% +but now starting from here +you can actually + + align:start position:0% +you can actually + + + align:start position:0% +you can actually +obtain finally Transformations on the + + align:start position:0% +obtain finally Transformations on the + + + align:start position:0% +obtain finally Transformations on the +field also using Q okay so we can + + align:start position:0% +field also using Q okay so we can + + + align:start position:0% +field also using Q okay so we can +generate finally transformations + + align:start position:0% + + + + align:start position:0% + +so let's consider say U + + align:start position:0% +so let's consider say U + + + align:start position:0% +so let's consider say U +Lambda Alpha so Lambda are just some + + align:start position:0% +Lambda Alpha so Lambda are just some + + + align:start position:0% +Lambda Alpha so Lambda are just some +parameters + + align:start position:0% +parameters + + + align:start position:0% +parameters +let's consider this quantity + + align:start position:0% + + + + align:start position:0% + +okay now I now experientiate this Cube + + align:start position:0% +okay now I now experientiate this Cube + + + align:start position:0% +okay now I now experientiate this Cube +so Q is the operator and Lambda is just + + align:start position:0% +so Q is the operator and Lambda is just + + + align:start position:0% +so Q is the operator and Lambda is just +some numbers okay + + align:start position:0% +some numbers okay + + + align:start position:0% +some numbers okay +Lambda is some constant parameters okay + + align:start position:0% +Lambda is some constant parameters okay + + + align:start position:0% +Lambda is some constant parameters okay +and again the alpha is sound yes + + align:start position:0% + + + + align:start position:0% + +the Heisenberg equation but here how + + align:start position:0% +the Heisenberg equation but here how + + + align:start position:0% +the Heisenberg equation but here how +would you evaluate this commentator not + + align:start position:0% +would you evaluate this commentator not + + + align:start position:0% +would you evaluate this commentator not +knowing the form of you but because he + + align:start position:0% +knowing the form of you but because he + + + align:start position:0% +knowing the form of you but because he +said it can depend on my uh time + + align:start position:0% +said it can depend on my uh time + + + align:start position:0% +said it can depend on my uh time +derivatives as well right yeah yeah yeah + + align:start position:0% +derivatives as well right yeah yeah yeah + + + align:start position:0% +derivatives as well right yeah yeah yeah +here just this General argument on the + + align:start position:0% +here just this General argument on the + + + align:start position:0% +here just this General argument on the +apply anymore so so in this case you + + align:start position:0% +apply anymore so so in this case you + + + align:start position:0% +apply anymore so so in this case you +really have to uh uh you can check the + + align:start position:0% +really have to uh uh you can check the + + + align:start position:0% +really have to uh uh you can check the +explicitly you can just write down the + + align:start position:0% +explicitly you can just write down the + + + align:start position:0% +explicitly you can just write down the +explicit value uh Express form of H and + + align:start position:0% +explicit value uh Express form of H and + + + align:start position:0% +explicit value uh Express form of H and +then then work out explicitly but you + + align:start position:0% +then then work out explicitly but you + + + align:start position:0% +then then work out explicitly but you +don't have to do it because we know this + + align:start position:0% +don't have to do it because we know this + + + align:start position:0% +don't have to do it because we know this +has to be true but just by set of + + align:start position:0% +has to be true but just by set of + + + align:start position:0% +has to be true but just by set of +consistency because we solved the + + align:start position:0% +consistency because we solved the + + + align:start position:0% +consistency because we solved the +Heisenberg equation yeah because the + + align:start position:0% +Heisenberg equation yeah because the + + + align:start position:0% +Heisenberg equation yeah because the +when we quantize it essentially we're + + align:start position:0% +when we quantize it essentially we're + + + align:start position:0% +when we quantize it essentially we're +solving the Heisenberg equation + + align:start position:0% + + + + align:start position:0% + +yeah but you can check it explicitly uh + + align:start position:0% +yeah but you can check it explicitly uh + + + align:start position:0% +yeah but you can check it explicitly uh +yourself that this is true yeah + + align:start position:0% + + + + align:start position:0% + +good + + align:start position:0% +good + + + align:start position:0% +good +so so here so so Lambda Alpha here just + + align:start position:0% +so so here so so Lambda Alpha here just + + + align:start position:0% +so so here so so Lambda Alpha here just +some + + align:start position:0% +some + + + align:start position:0% +some +collection of + + align:start position:0% + + + + align:start position:0% + +finite + + align:start position:0% +finite + + + align:start position:0% +finite +transformation parameters + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +so this can be used to uh uh generate + + align:start position:0% +so this can be used to uh uh generate + + + align:start position:0% +so this can be used to uh uh generate +the finite transformations + + align:start position:0% +the finite transformations + + + align:start position:0% +the finite transformations +okay so if you act you are you lamb the + + align:start position:0% +okay so if you act you are you lamb the + + + align:start position:0% +okay so if you act you are you lamb the +alpha + + align:start position:0% + + + + align:start position:0% + +Phi + + align:start position:0% +Phi + + + align:start position:0% +Phi +by a + + align:start position:0% +by a + + + align:start position:0% +by a +and you Lambda Alpha + + align:start position:0% + + + + align:start position:0% + +dagger and then you just get five a + + align:start position:0% +dagger and then you just get five a + + + align:start position:0% +dagger and then you just get five a +prime and now this is a finite + + align:start position:0% +prime and now this is a finite + + + align:start position:0% +prime and now this is a finite +transformation of finite symmetric + + align:start position:0% +transformation of finite symmetric + + + align:start position:0% +transformation of finite symmetric +transformation of Phi okay + + align:start position:0% +transformation of Phi okay + + + align:start position:0% +transformation of Phi okay +and when you expand when Lambda Alpha is + + align:start position:0% +and when you expand when Lambda Alpha is + + + align:start position:0% +and when you expand when Lambda Alpha is +infinitesimal + + align:start position:0% +infinitesimal + + + align:start position:0% +infinitesimal +and then you can just expand this + + align:start position:0% +and then you can just expand this + + + align:start position:0% +and then you can just expand this +exponential then the leading term + + align:start position:0% +exponential then the leading term + + + align:start position:0% +exponential then the leading term +becomes this one okay + + align:start position:0% +becomes this one okay + + + align:start position:0% +becomes this one okay +the leading term becomes this one and uh + + align:start position:0% +the leading term becomes this one and uh + + + align:start position:0% +the leading term becomes this one and uh +yeah so so when + + align:start position:0% +yeah so so when + + + align:start position:0% +yeah so so when +Lambda Alpha equal to Epsilon Alpha goes + + align:start position:0% +Lambda Alpha equal to Epsilon Alpha goes + + + align:start position:0% +Lambda Alpha equal to Epsilon Alpha goes +to zero + + align:start position:0% +to zero + + + align:start position:0% +to zero +and these equations this equation star + + align:start position:0% +and these equations this equation star + + + align:start position:0% +and these equations this equation star +and Then star star + + align:start position:0% +and Then star star + + + align:start position:0% +and Then star star +reduces + + align:start position:0% + + + + align:start position:0% + +star + + align:start position:0% +star + + + align:start position:0% +star +as leading non-trivial order + + align:start position:0% + + + + align:start position:0% + +when you expand the exponential okay + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +so this can be a tongue in general just + + align:start position:0% +so this can be a tongue in general just + + + align:start position:0% +so this can be a tongue in general just +so the reason this is true + + align:start position:0% +so the reason this is true + + + align:start position:0% +so the reason this is true +without even doing any doing any + + align:start position:0% +without even doing any doing any + + + align:start position:0% +without even doing any doing any +calculation you can just imagine you can + + align:start position:0% +calculation you can just imagine you can + + + align:start position:0% +calculation you can just imagine you can +build this U this in this finite + + align:start position:0% +build this U this in this finite + + + align:start position:0% +build this U this in this finite +transformation by infinite number of + + align:start position:0% +transformation by infinite number of + + + align:start position:0% +transformation by infinite number of +infinitesimal transformations + + align:start position:0% + + + + align:start position:0% + +so when you build them up and then you + + align:start position:0% +so when you build them up and then you + + + align:start position:0% +so when you build them up and then you +will just generate the finite + + align:start position:0% +will just generate the finite + + + align:start position:0% +will just generate the finite +transformation + + align:start position:0% + + + + align:start position:0% + +so you already worked out the example in + + align:start position:0% +so you already worked out the example in + + + align:start position:0% +so you already worked out the example in +your preset + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% + + + + align:start position:0% + +so you already worked out the example in + + align:start position:0% +so you already worked out the example in + + + align:start position:0% +so you already worked out the example in +your pizza that + + align:start position:0% +your pizza that + + + align:start position:0% +your pizza that +if you can see the HT + + align:start position:0% +if you can see the HT + + + align:start position:0% +if you can see the HT +minus + + align:start position:0% +minus + + + align:start position:0% +minus +I + + align:start position:0% +I + + + align:start position:0% +I +pi + + align:start position:0% + + + + align:start position:0% + +x i + + align:start position:0% +x i + + + align:start position:0% +x i +acting on five zero + + align:start position:0% +acting on five zero + + + align:start position:0% +acting on five zero +minus i h t + + align:start position:0% +minus i h t + + + align:start position:0% +minus i h t +Plus + + align:start position:0% +Plus + + + align:start position:0% +Plus +ipixi + + align:start position:0% +ipixi + + + align:start position:0% +ipixi +and then this just give you 5 p x i t x + + align:start position:0% +and then this just give you 5 p x i t x + + + align:start position:0% +and then this just give you 5 p x i t x +okay + + align:start position:0% +okay + + + align:start position:0% +okay +just give you five DX + + align:start position:0% +just give you five DX + + + align:start position:0% +just give you five DX +and so + + align:start position:0% +and so + + + align:start position:0% +and so +so this is so so here + + align:start position:0% +so this is so so here + + + align:start position:0% +so this is so so here +HT minus + + align:start position:0% +HT minus + + + align:start position:0% +HT minus +p i x i + + align:start position:0% +p i x i + + + align:start position:0% +p i x i +is our Lambda Alpha to Alpha here okay + + align:start position:0% +is our Lambda Alpha to Alpha here okay + + + align:start position:0% +is our Lambda Alpha to Alpha here okay +so Alpha here runs + + align:start position:0% +so Alpha here runs + + + align:start position:0% +so Alpha here runs +0 and I Direction okay so in the zero + + align:start position:0% +0 and I Direction okay so in the zero + + + align:start position:0% +0 and I Direction okay so in the zero +direction of the T now is just some + + align:start position:0% +direction of the T now is just some + + + align:start position:0% +direction of the T now is just some +parameter + + align:start position:0% +parameter + + + align:start position:0% +parameter +and the uh uh and the Lambda + + align:start position:0% +and the uh uh and the Lambda + + + align:start position:0% +and the uh uh and the Lambda +Alpha equal to T and the minus x i okay + + align:start position:0% +Alpha equal to T and the minus x i okay + + + align:start position:0% +Alpha equal to T and the minus x i okay +and then Q off I just uh + + align:start position:0% +and then Q off I just uh + + + align:start position:0% +and then Q off I just uh +and the Q over here + + align:start position:0% +and the Q over here + + + align:start position:0% +and the Q over here +is equal to yeah TXI let me just two t x + + align:start position:0% +is equal to yeah TXI let me just two t x + + + align:start position:0% +is equal to yeah TXI let me just two t x +i + + align:start position:0% +i + + + align:start position:0% +i +and the Q Alpha here is just h + + align:start position:0% +and the Q Alpha here is just h + + + align:start position:0% +and the Q Alpha here is just h +minus pi + + align:start position:0% +minus pi + + + align:start position:0% +minus pi +okay + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +good so this is just the example of that + + align:start position:0% +good so this is just the example of that + + + align:start position:0% +good so this is just the example of that +okay this is just example of that + + align:start position:0% + + + + align:start position:0% + +and also you can consider Lawrence + + align:start position:0% +and also you can consider Lawrence + + + align:start position:0% +and also you can consider Lawrence +transformation + + align:start position:0% +transformation + + + align:start position:0% +transformation +so another example is a low range + + align:start position:0% +so another example is a low range + + + align:start position:0% +so another example is a low range +transformation + + align:start position:0% + + + + align:start position:0% + +so let's consider so so in your P set + + align:start position:0% +so let's consider so so in your P set + + + align:start position:0% +so let's consider so so in your P set +you already + + align:start position:0% +you already + + + align:start position:0% +you already +so in the low range transformation uh uh + + align:start position:0% +so in the low range transformation uh uh + + + align:start position:0% +so in the low range transformation uh uh +the conserved charges + + align:start position:0% +the conserved charges + + + align:start position:0% +the conserved charges +actually there are six of them + + align:start position:0% +actually there are six of them + + + align:start position:0% +actually there are six of them +okay you knew + + align:start position:0% + + + + align:start position:0% + +going from + + align:start position:0% +going from + + + align:start position:0% +going from +one zero three okay so so they all + + align:start position:0% +one zero three okay so so they all + + + align:start position:0% +one zero three okay so so they all +together six conserved charges + + align:start position:0% +together six conserved charges + + + align:start position:0% +together six conserved charges +associated with an orange transformation + + align:start position:0% +associated with an orange transformation + + + align:start position:0% +associated with an orange transformation +three rotations and three boosts okay + + align:start position:0% +three rotations and three boosts okay + + + align:start position:0% +three rotations and three boosts okay +and then so when you write the final + + align:start position:0% +and then so when you write the final + + + align:start position:0% +and then so when you write the final +transformation + + align:start position:0% +transformation + + + align:start position:0% +transformation +and then you will have six parameters + + align:start position:0% + + + + align:start position:0% + +okay you have six parameters and Omega + + align:start position:0% +okay you have six parameters and Omega + + + align:start position:0% +okay you have six parameters and Omega +mu mu + + align:start position:0% +mu mu + + + align:start position:0% +mu mu +and this because mu mu is anti-symmetric + + align:start position:0% +and this because mu mu is anti-symmetric + + + align:start position:0% +and this because mu mu is anti-symmetric +which you worked out in your PSAT + + align:start position:0% +which you worked out in your PSAT + + + align:start position:0% +which you worked out in your PSAT +so this parameter should also be + + align:start position:0% +so this parameter should also be + + + align:start position:0% +so this parameter should also be +anti-symmetric + + align:start position:0% +anti-symmetric + + + align:start position:0% +anti-symmetric +okay and uh so they are finite + + align:start position:0% + + + + align:start position:0% + +angles + + align:start position:0% + + + + align:start position:0% + +Fahrenheit angles + + align:start position:0% +Fahrenheit angles + + + align:start position:0% +Fahrenheit angles +not definite angios + + align:start position:0% +not definite angios + + + align:start position:0% +not definite angios +finite angles + + align:start position:0% +finite angles + + + align:start position:0% +finite angles +and + + align:start position:0% +and + + + align:start position:0% +and +boost + + align:start position:0% +boost + + + align:start position:0% +boost +okay so so the so so essentially the lab + + align:start position:0% +okay so so the so so essentially the lab + + + align:start position:0% +okay so so the so so essentially the lab +they give the parameters for the finite + + align:start position:0% +they give the parameters for the finite + + + align:start position:0% +they give the parameters for the finite +rotation angles and the Boost + + align:start position:0% +rotation angles and the Boost + + + align:start position:0% +rotation angles and the Boost +and so uh so that generates a low range + + align:start position:0% +and so uh so that generates a low range + + + align:start position:0% +and so uh so that generates a low range +transformation okay they generate the + + align:start position:0% +transformation okay they generate the + + + align:start position:0% +transformation okay they generate the +orange transformation + + align:start position:0% + + + + align:start position:0% + +and so for example you uh say if you act + + align:start position:0% +and so for example you uh say if you act + + + align:start position:0% +and so for example you uh say if you act +on + + align:start position:0% +on + + + align:start position:0% +on +new Lambda + + align:start position:0% +new Lambda + + + align:start position:0% +new Lambda +on 5X + + align:start position:0% +on 5X + + + align:start position:0% +on 5X +and you Lambda you can check + + align:start position:0% +and you Lambda you can check + + + align:start position:0% +and you Lambda you can check +dagger on fire x what you get + + align:start position:0% +dagger on fire x what you get + + + align:start position:0% +dagger on fire x what you get +is Phi Prime X + + align:start position:0% +is Phi Prime X + + + align:start position:0% +is Phi Prime X +and the Phi Prime X is also the same as + + align:start position:0% +and the Phi Prime X is also the same as + + + align:start position:0% +and the Phi Prime X is also the same as +5 Lambda 1 and X okay so so here Lambda + + align:start position:0% +5 Lambda 1 and X okay so so here Lambda + + + align:start position:0% +5 Lambda 1 and X okay so so here Lambda +so here Lambda 1 x is the low range + + align:start position:0% +so here Lambda 1 x is the low range + + + align:start position:0% +so here Lambda 1 x is the low range +transformation + + align:start position:0% + + + + align:start position:0% + +so X mu + + align:start position:0% + + + + align:start position:0% + +with parameter + + align:start position:0% + + + + align:start position:0% + +determined by uh uh or yeah just Omega + + align:start position:0% +determined by uh uh or yeah just Omega + + + align:start position:0% +determined by uh uh or yeah just Omega +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so describe the Lambda is the + + align:start position:0% +so describe the Lambda is the + + + align:start position:0% +so describe the Lambda is the +corresponding orange transformation + + align:start position:0% + + + + align:start position:0% + +is this clear + + align:start position:0% +is this clear + + + align:start position:0% +is this clear +yes + + align:start position:0% +yes + + + align:start position:0% +yes +so you assumed like that you can + + align:start position:0% +so you assumed like that you can + + + align:start position:0% +so you assumed like that you can +represent the I guess the operators that + + align:start position:0% +represent the I guess the operators that + + + align:start position:0% +represent the I guess the operators that +perform these Transformations like this + + align:start position:0% +perform these Transformations like this + + + align:start position:0% +perform these Transformations like this +but don't you have to like think about + + align:start position:0% +but don't you have to like think about + + + align:start position:0% +but don't you have to like think about +if it follows the algebra such that you + + align:start position:0% +if it follows the algebra such that you + + + align:start position:0% +if it follows the algebra such that you +can represent it like this or like the + + align:start position:0% +can represent it like this or like the + + + align:start position:0% +can represent it like this or like the +group of Transformations yeah yeah yeah + + align:start position:0% +group of Transformations yeah yeah yeah + + + align:start position:0% +group of Transformations yeah yeah yeah +indeed so so here is not uh here is not + + align:start position:0% +indeed so so here is not uh here is not + + + align:start position:0% +indeed so so here is not uh here is not +say I assume here I'm just directly + + align:start position:0% +say I assume here I'm just directly + + + align:start position:0% +say I assume here I'm just directly +telling you the result uh it's just when + + align:start position:0% +telling you the result uh it's just when + + + align:start position:0% +telling you the result uh it's just when +you uh build yeah + + align:start position:0% + + + + align:start position:0% + +so so if you want to generate the uh uh + + align:start position:0% +so so if you want to generate the uh uh + + + align:start position:0% +so so if you want to generate the uh uh +um yeah I'm just directly already + + align:start position:0% +um yeah I'm just directly already + + + align:start position:0% +um yeah I'm just directly already +directly tell you the answer + + align:start position:0% + + + + align:start position:0% + +if you do the composition of the + + align:start position:0% +if you do the composition of the + + + align:start position:0% +if you do the composition of the +infinitesimal transformation you will + + align:start position:0% +infinitesimal transformation you will + + + align:start position:0% +infinitesimal transformation you will +get that yeah yeah the reason I write + + align:start position:0% +get that yeah yeah the reason I write + + + align:start position:0% +get that yeah yeah the reason I write +down this explicitly uh immediately + + align:start position:0% +down this explicitly uh immediately + + + align:start position:0% +down this explicitly uh immediately +because you should have already seen + + align:start position:0% +because you should have already seen + + + align:start position:0% +because you should have already seen +this in quantum mechanics yeah because + + align:start position:0% +this in quantum mechanics yeah because + + + align:start position:0% +this in quantum mechanics yeah because +that's how you do the angular momentum + + align:start position:0% +that's how you do the angular momentum + + + align:start position:0% +that's how you do the angular momentum +yeah in quantum mechanics when you do + + align:start position:0% +yeah in quantum mechanics when you do + + + align:start position:0% +yeah in quantum mechanics when you do +the angular momentum the way is the same + + align:start position:0% +the angular momentum the way is the same + + + align:start position:0% +the angular momentum the way is the same +thing yeah yeah here we just generalize + + align:start position:0% +thing yeah yeah here we just generalize + + + align:start position:0% +thing yeah yeah here we just generalize +it to to uh to General symmetries yeah + + align:start position:0% +it to to uh to General symmetries yeah + + + align:start position:0% +it to to uh to General symmetries yeah +yes + + align:start position:0% +yes + + + align:start position:0% +yes +yes it was kind of some similar question + + align:start position:0% +yes it was kind of some similar question + + + align:start position:0% +yes it was kind of some similar question +but just like + + align:start position:0% +but just like + + + align:start position:0% +but just like +um so like this is like a general + + align:start position:0% +um so like this is like a general + + + align:start position:0% +um so like this is like a general +procedure if you have a symmetry to get + + align:start position:0% +procedure if you have a symmetry to get + + + align:start position:0% +procedure if you have a symmetry to get +the representation on your own space + + align:start position:0% +the representation on your own space + + + align:start position:0% +the representation on your own space +yeah like this yeah like in q1 we + + align:start position:0% +yeah like this yeah like in q1 we + + + align:start position:0% +yeah like this yeah like in q1 we +usually just postulate that there's the + + align:start position:0% +usually just postulate that there's the + + + align:start position:0% +usually just postulate that there's the +inventory operator and then demand that + + align:start position:0% +inventory operator and then demand that + + + align:start position:0% +inventory operator and then demand that +the group holds right yeah so like do we + + align:start position:0% +the group holds right yeah so like do we + + + align:start position:0% +the group holds right yeah so like do we +need to show that those things get this + + align:start position:0% +need to show that those things get this + + + align:start position:0% +need to show that those things get this +this preserves the purple or is that not + + align:start position:0% +this preserves the purple or is that not + + + align:start position:0% +this preserves the purple or is that not +yeah yeah so this is + + align:start position:0% + + + + align:start position:0% + +yeah I didn't go into that but this is + + align:start position:0% +yeah I didn't go into that but this is + + + align:start position:0% +yeah I didn't go into that but this is +guaranteed essentially that's how you + + align:start position:0% +guaranteed essentially that's how you + + + align:start position:0% +guaranteed essentially that's how you +yeah in the uh this is how you build the + + align:start position:0% +yeah in the uh this is how you build the + + + align:start position:0% +yeah in the uh this is how you build the +algebra because the algebra is also uh + + align:start position:0% +algebra because the algebra is also uh + + + align:start position:0% +algebra because the algebra is also uh +the the finite transformation is also + + align:start position:0% +the the finite transformation is also + + + align:start position:0% +the the finite transformation is also +built up by by Infinity transformations + + align:start position:0% +built up by by Infinity transformations + + + align:start position:0% +built up by by Infinity transformations +and so so you're saying it guaranteed uh + + align:start position:0% +and so so you're saying it guaranteed uh + + + align:start position:0% +and so so you're saying it guaranteed uh +yes + + align:start position:0% +yes + + + align:start position:0% +yes +so there is a theory of lead groups and + + align:start position:0% +so there is a theory of lead groups and + + + align:start position:0% +so there is a theory of lead groups and +the algebra behind this + + align:start position:0% +the algebra behind this + + + align:start position:0% +the algebra behind this +yes I didn't go into that um so so some + + align:start position:0% +yes I didn't go into that um so so some + + + align:start position:0% +yes I didn't go into that um so so some +of you may already sing a little bit of + + align:start position:0% +of you may already sing a little bit of + + + align:start position:0% +of you may already sing a little bit of +this when you talk about angular + + align:start position:0% +this when you talk about angular + + + align:start position:0% +this when you talk about angular +momentum saying quantum mechanics so + + align:start position:0% +momentum saying quantum mechanics so + + + align:start position:0% +momentum saying quantum mechanics so +it's exactly the same story there + + align:start position:0% +it's exactly the same story there + + + align:start position:0% +it's exactly the same story there +yes + + align:start position:0% + + + + align:start position:0% + +correspond to the angular momentum being + + align:start position:0% +correspond to the angular momentum being + + + align:start position:0% +correspond to the angular momentum being +preserved yeah but what is like the + + align:start position:0% +preserved yeah but what is like the + + + align:start position:0% +preserved yeah but what is like the +intuition for like the thing that's + + align:start position:0% +intuition for like the thing that's + + + align:start position:0% +intuition for like the thing that's +preserved in boosts + + align:start position:0% +preserved in boosts + + + align:start position:0% +preserved in boosts +yeah yeah it's a uh yeah indeed there's + + align:start position:0% +yeah yeah it's a uh yeah indeed there's + + + align:start position:0% +yeah yeah it's a uh yeah indeed there's +no worry + + align:start position:0% +no worry + + + align:start position:0% +no worry +intuitive way to think about it also + + align:start position:0% +intuitive way to think about it also + + + align:start position:0% +intuitive way to think about it also +it's not that useful you know you can + + align:start position:0% +it's not that useful you know you can + + + align:start position:0% +it's not that useful you know you can +define a boost charge so so so if you + + align:start position:0% +define a boost charge so so so if you + + + align:start position:0% +define a boost charge so so so if you +can see the the all the spatial + + align:start position:0% +can see the the all the spatial + + + align:start position:0% +can see the the all the spatial +components and if you consider the old + + align:start position:0% +components and if you consider the old + + + align:start position:0% +components and if you consider the old +IJ here then these are the angular + + align:start position:0% +IJ here then these are the angular + + + align:start position:0% +IJ here then these are the angular +momentum operator and this is the your + + align:start position:0% +momentum operator and this is the your + + + align:start position:0% +momentum operator and this is the your +standard algorithm operator which you + + align:start position:0% +standard algorithm operator which you + + + align:start position:0% +standard algorithm operator which you +have seen and if you look at zero I and + + align:start position:0% +have seen and if you look at zero I and + + + align:start position:0% +have seen and if you look at zero I and +then that was sometimes we call Boost + + align:start position:0% +then that was sometimes we call Boost + + + align:start position:0% +then that was sometimes we call Boost +charge it generates the Boost + + align:start position:0% +charge it generates the Boost + + + align:start position:0% +charge it generates the Boost +but in terms of the conserved number + + align:start position:0% +but in terms of the conserved number + + + align:start position:0% +but in terms of the conserved number +yeah we don't have + + align:start position:0% +yeah we don't have + + + align:start position:0% +yeah we don't have +we don't use it in the in the essential + + align:start position:0% +we don't use it in the in the essential + + + align:start position:0% +we don't use it in the in the essential +Way say say say in other contexts yeah + + align:start position:0% + + + + align:start position:0% + +yeah yeah it just does not give you + + align:start position:0% +yeah yeah it just does not give you + + + align:start position:0% +yeah yeah it just does not give you +something additional + + align:start position:0% +something additional + + + align:start position:0% +something additional +just a normally when you deal with + + align:start position:0% +just a normally when you deal with + + + align:start position:0% +just a normally when you deal with +physical problems say angular momentum + + align:start position:0% +physical problems say angular momentum + + + align:start position:0% +physical problems say angular momentum +kind of basic momentum calibration + + align:start position:0% +kind of basic momentum calibration + + + align:start position:0% +kind of basic momentum calibration +energy conservations right enough uh + + align:start position:0% +energy conservations right enough uh + + + align:start position:0% +energy conservations right enough uh +yeah + + align:start position:0% + + + + align:start position:0% + +yeah you normally don't need to use a + + align:start position:0% +yeah you normally don't need to use a + + + align:start position:0% +yeah you normally don't need to use a +boost charge condemnation yeah to solve + + align:start position:0% +boost charge condemnation yeah to solve + + + align:start position:0% +boost charge condemnation yeah to solve +your problem + + align:start position:0% +your problem + + + align:start position:0% +your problem +yeah so that's why we don't see this + + align:start position:0% +yeah so that's why we don't see this + + + align:start position:0% +yeah so that's why we don't see this +object very often say when you discuss + + align:start position:0% +object very often say when you discuss + + + align:start position:0% +object very often say when you discuss +special relativity or or other things + + align:start position:0% +special relativity or or other things + + + align:start position:0% +special relativity or or other things +but + + align:start position:0% + + + + align:start position:0% + +but here plays a very important role + + align:start position:0% +but here plays a very important role + + + align:start position:0% +but here plays a very important role +that in Quantum field Theory this is the + + align:start position:0% +that in Quantum field Theory this is the + + + align:start position:0% +that in Quantum field Theory this is the +operator which generates + + align:start position:0% +operator which generates + + + align:start position:0% +operator which generates +the Boost symmetry okay if you want to + + align:start position:0% +the Boost symmetry okay if you want to + + + align:start position:0% +the Boost symmetry okay if you want to +do a boost uh General do a boost in your + + align:start position:0% +do a boost uh General do a boost in your + + + align:start position:0% +do a boost uh General do a boost in your +hearable space that's the operator to do + + align:start position:0% +hearable space that's the operator to do + + + align:start position:0% +hearable space that's the operator to do +it okay + + align:start position:0% + + + + align:start position:0% + +okay other questions + + align:start position:0% + + + + align:start position:0% + +okay good + + align:start position:0% + + + + align:start position:0% + +good + + align:start position:0% +good + + + align:start position:0% +good +yeah so in your presets + + align:start position:0% +yeah so in your presets + + + align:start position:0% +yeah so in your presets +um + + align:start position:0% +um + + + align:start position:0% +um +yeah another example is the phase + + align:start position:0% +yeah another example is the phase + + + align:start position:0% +yeah another example is the phase +rotation let me just very quickly wrote + + align:start position:0% +rotation let me just very quickly wrote + + + align:start position:0% +rotation let me just very quickly wrote +here and so so another example + + align:start position:0% +here and so so another example + + + align:start position:0% +here and so so another example +is the phase rotation if you have a + + align:start position:0% +is the phase rotation if you have a + + + align:start position:0% +is the phase rotation if you have a +complex scalar field + + align:start position:0% +complex scalar field + + + align:start position:0% +complex scalar field +okay + + align:start position:0% + + + + align:start position:0% + +so there we show there's another charge + + align:start position:0% +so there we show there's another charge + + + align:start position:0% +so there we show there's another charge +was running to the face rotation there's + + align:start position:0% +was running to the face rotation there's + + + align:start position:0% +was running to the face rotation there's +another current uh corresponding to you + + align:start position:0% +another current uh corresponding to you + + + align:start position:0% +another current uh corresponding to you +can rotate the face to the field that's + + align:start position:0% +can rotate the face to the field that's + + + align:start position:0% +can rotate the face to the field that's +a symmetry and uh and so so that will + + align:start position:0% +a symmetry and uh and so so that will + + + align:start position:0% +a symmetry and uh and so so that will +generate the charge Q + + align:start position:0% + + + + align:start position:0% + +and then if you have Alpha Q + + align:start position:0% +and then if you have Alpha Q + + + align:start position:0% +and then if you have Alpha Q +and then when you act down Phi + + align:start position:0% + + + + align:start position:0% + +and then you can just check explicitly + + align:start position:0% +and then you can just check explicitly + + + align:start position:0% +and then you can just check explicitly +that we generate the phase rotation in + + align:start position:0% +that we generate the phase rotation in + + + align:start position:0% +that we generate the phase rotation in +Phi okay + + align:start position:0% + + + + align:start position:0% + +and and we'll generate for this rotation + + align:start position:0% +and and we'll generate for this rotation + + + align:start position:0% +and and we'll generate for this rotation +right + + align:start position:0% + + + + align:start position:0% + +foreign + + align:start position:0% + + + + align:start position:0% + +good + + align:start position:0% + + + + align:start position:0% + +so um + + align:start position:0% + + + + align:start position:0% + +yeah so let's conclude our discussion of + + align:start position:0% +yeah so let's conclude our discussion of + + + align:start position:0% +yeah so let's conclude our discussion of +the um + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +over the real scalar field + + align:start position:0% + + + + align:start position:0% + +now we can move to a new part + + align:start position:0% + + + + align:start position:0% + +so before we go to new parts of your + + align:start position:0% +so before we go to new parts of your + + + align:start position:0% +so before we go to new parts of your +your last chance to ask questions about + + align:start position:0% +your last chance to ask questions about + + + align:start position:0% +your last chance to ask questions about +this part + + align:start position:0% + + + + align:start position:0% + +okay great + + align:start position:0% + + + + align:start position:0% + +so now let's very quickly + + align:start position:0% + + + + align:start position:0% + +talk about + + align:start position:0% + + + + align:start position:0% + +so let's very quickly talk about the + + align:start position:0% +so let's very quickly talk about the + + + align:start position:0% +so let's very quickly talk about the +complex scale field + + align:start position:0% + + + + align:start position:0% + +and uh + + align:start position:0% +and uh + + + align:start position:0% +and uh +um you can see the complex scalar field + + align:start position:0% +um you can see the complex scalar field + + + align:start position:0% +um you can see the complex scalar field +we get something new we get the concept + + align:start position:0% +we get something new we get the concept + + + align:start position:0% +we get something new we get the concept +of anti-particle + + align:start position:0% +of anti-particle + + + align:start position:0% +of anti-particle +okay so now let's consider the following + + align:start position:0% +okay so now let's consider the following + + + align:start position:0% +okay so now let's consider the following +LaGrange intensity + + align:start position:0% + + + + align:start position:0% + +again we only consider quadratic + + align:start position:0% +again we only consider quadratic + + + align:start position:0% +again we only consider quadratic +the simplest only quadratic uh + + align:start position:0% +the simplest only quadratic uh + + + align:start position:0% +the simplest only quadratic uh +Lagro engine + + align:start position:0% +Lagro engine + + + align:start position:0% +Lagro engine +but now the file is complex okay + + align:start position:0% + + + + align:start position:0% + +where it's complex + + align:start position:0% + + + + align:start position:0% + +so um + + align:start position:0% +so um + + + align:start position:0% +so um +so complex + + align:start position:0% +so complex + + + align:start position:0% +so complex +is also the same as too real + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so you can decompose + + align:start position:0% +so you can decompose + + + align:start position:0% +so you can decompose +you can decompose Phi into its real path + + align:start position:0% +you can decompose Phi into its real path + + + align:start position:0% +you can decompose Phi into its real path +and imaginary part + + align:start position:0% +and imaginary part + + + align:start position:0% +and imaginary part +and if you plug them in here + + align:start position:0% +and if you plug them in here + + + align:start position:0% +and if you plug them in here +and then you find you just get two + + align:start position:0% +and then you find you just get two + + + align:start position:0% +and then you find you just get two +separate P's and one is the freeze real + + align:start position:0% +separate P's and one is the freeze real + + + align:start position:0% +separate P's and one is the freeze real +scalar field for the real part and the Y + + align:start position:0% +scalar field for the real part and the Y + + + align:start position:0% +scalar field for the real part and the Y +is the free scalar field for the + + align:start position:0% +is the free scalar field for the + + + align:start position:0% +is the free scalar field for the +imaginary part okay because each one + + align:start position:0% +imaginary part okay because each one + + + align:start position:0% +imaginary part okay because each one +yeah if you write five equal to a plus + + align:start position:0% +yeah if you write five equal to a plus + + + align:start position:0% +yeah if you write five equal to a plus +IB and here just become a squared plus b + + align:start position:0% +IB and here just become a squared plus b + + + align:start position:0% +IB and here just become a squared plus b +squared here it's also a plus b plus b + + align:start position:0% +squared here it's also a plus b plus b + + + align:start position:0% +squared here it's also a plus b plus b +squared okay + + align:start position:0% +squared okay + + + align:start position:0% +squared okay +but there's a reason we write the in + + align:start position:0% +but there's a reason we write the in + + + align:start position:0% +but there's a reason we write the in +yeah so essentially we just get two + + align:start position:0% +yeah so essentially we just get two + + + align:start position:0% +yeah so essentially we just get two +copies of our previous Theory + + align:start position:0% +copies of our previous Theory + + + align:start position:0% +copies of our previous Theory +okay we just get two copies of a + + align:start position:0% +okay we just get two copies of a + + + align:start position:0% +okay we just get two copies of a +previously so you say oh then it's + + align:start position:0% +previously so you say oh then it's + + + align:start position:0% +previously so you say oh then it's +trigger why should we just consider this + + align:start position:0% +trigger why should we just consider this + + + align:start position:0% +trigger why should we just consider this +we just get two copies of previously + + align:start position:0% +we just get two copies of previously + + + align:start position:0% +we just get two copies of previously +but the disadvantage + + align:start position:0% +but the disadvantage + + + align:start position:0% +but the disadvantage +but there's some conception something + + align:start position:0% +but there's some conception something + + + align:start position:0% +but there's some conception something +conceptually new when we write in this + + align:start position:0% +conceptually new when we write in this + + + align:start position:0% +conceptually new when we write in this +form + + align:start position:0% +form + + + align:start position:0% +form +uh there's advantage to write in this + + align:start position:0% +uh there's advantage to write in this + + + align:start position:0% +uh there's advantage to write in this +form rather than write as two separate + + align:start position:0% +form rather than write as two separate + + + align:start position:0% +form rather than write as two separate +identical scalar field Theory + + align:start position:0% +identical scalar field Theory + + + align:start position:0% +identical scalar field Theory +it's precisely in this form + + align:start position:0% + + + + align:start position:0% + +this phase symmetry is manifest okay if + + align:start position:0% +this phase symmetry is manifest okay if + + + align:start position:0% +this phase symmetry is manifest okay if +I just write it as a two separate real + + align:start position:0% +I just write it as a two separate real + + + align:start position:0% +I just write it as a two separate real +scalar field and then this face image is + + align:start position:0% +scalar field and then this face image is + + + align:start position:0% +scalar field and then this face image is +not manifest okay + + align:start position:0% +not manifest okay + + + align:start position:0% +not manifest okay +and the cell here in this form there's a + + align:start position:0% +and the cell here in this form there's a + + + align:start position:0% +and the cell here in this form there's a +face image manifest Okay so + + align:start position:0% +face image manifest Okay so + + + align:start position:0% +face image manifest Okay so +so if I goes to + + align:start position:0% +so if I goes to + + + align:start position:0% +so if I goes to +I Alpha Phi + + align:start position:0% +I Alpha Phi + + + align:start position:0% +I Alpha Phi +and so you see this + + align:start position:0% + + + + align:start position:0% + +okay so there's a when you write it in + + align:start position:0% +okay so there's a when you write it in + + + align:start position:0% +okay so there's a when you write it in +terms of real and imaginary part this + + align:start position:0% +terms of real and imaginary part this + + + align:start position:0% +terms of real and imaginary part this +corresponding to rotation between the + + align:start position:0% +corresponding to rotation between the + + + align:start position:0% +corresponding to rotation between the +real and imaginary part + + align:start position:0% +real and imaginary part + + + align:start position:0% +real and imaginary part +and uh yeah + + align:start position:0% + + + + align:start position:0% + +good + + align:start position:0% + + + + align:start position:0% + +and equation motion is the same + + align:start position:0% +and equation motion is the same + + + align:start position:0% +and equation motion is the same +because it's just the + + align:start position:0% +because it's just the + + + align:start position:0% +because it's just the +um + + align:start position:0% + + + + align:start position:0% + +because it's a you can easily Define + + align:start position:0% +because it's a you can easily Define + + + align:start position:0% +because it's a you can easily Define +equation motion is the same + + align:start position:0% +equation motion is the same + + + align:start position:0% +equation motion is the same +okay and uh + + align:start position:0% +okay and uh + + + align:start position:0% +okay and uh +um + + align:start position:0% +um + + + align:start position:0% +um +yeah because just two copies of your + + align:start position:0% +yeah because just two copies of your + + + align:start position:0% +yeah because just two copies of your +previous theory of course equation + + align:start position:0% +previous theory of course equation + + + align:start position:0% +previous theory of course equation +motion should be the same + + align:start position:0% +motion should be the same + + + align:start position:0% +motion should be the same +and the the LaGrange intensity or the + + align:start position:0% +and the the LaGrange intensity or the + + + align:start position:0% +and the the LaGrange intensity or the +the momentum density for Phi + + align:start position:0% + + + + align:start position:0% + +then it become + + align:start position:0% +then it become + + + align:start position:0% +then it become +partial zero five star + + align:start position:0% +partial zero five star + + + align:start position:0% +partial zero five star +and the partial zip files star + + align:start position:0% +and the partial zip files star + + + align:start position:0% +and the partial zip files star +partial zero five okay so we treat we + + align:start position:0% +partial zero five okay so we treat we + + + align:start position:0% +partial zero five okay so we treat we +can treat + + align:start position:0% +can treat + + + align:start position:0% +can treat +Phi and the five star as two independent + + align:start position:0% +Phi and the five star as two independent + + + align:start position:0% +Phi and the five star as two independent +Fields okay + + align:start position:0% +Fields okay + + + align:start position:0% +Fields okay +and then and then the canonical momentum + + align:start position:0% +and then and then the canonical momentum + + + align:start position:0% +and then and then the canonical momentum +say say if you take derivative with + + align:start position:0% +say say if you take derivative with + + + align:start position:0% +say say if you take derivative with +partial zero Phi then you get the + + align:start position:0% +partial zero Phi then you get the + + + align:start position:0% +partial zero Phi then you get the +partial zero five star and the vice + + align:start position:0% +partial zero five star and the vice + + + align:start position:0% +partial zero five star and the vice +versa okay so so the complex accounting + + align:start position:0% +versa okay so so the complex accounting + + + align:start position:0% +versa okay so so the complex accounting +momentum like that + + align:start position:0% +momentum like that + + + align:start position:0% +momentum like that +okay + + align:start position:0% + + + + align:start position:0% + +so we can now write down again we can + + align:start position:0% +so we can now write down again we can + + + align:start position:0% +so we can now write down again we can +just write down the most General + + align:start position:0% +just write down the most General + + + align:start position:0% +just write down the most General +Solutions + + align:start position:0% + + + + align:start position:0% + +so the basis of solutions is the same + + align:start position:0% + + + + align:start position:0% + +same set + + align:start position:0% + + + + align:start position:0% + +of solutions as before + + align:start position:0% + + + + align:start position:0% + +we just have + + align:start position:0% +we just have + + + align:start position:0% +we just have +u k + + align:start position:0% + + + + align:start position:0% + +x equal to minus I Omega k + + align:start position:0% +x equal to minus I Omega k + + + align:start position:0% +x equal to minus I Omega k +t plus ikx + + align:start position:0% + + + + align:start position:0% + +and then you have UK + + align:start position:0% +and then you have UK + + + align:start position:0% +and then you have UK +X star + + align:start position:0% +X star + + + align:start position:0% +X star +okay + + align:start position:0% +okay + + + align:start position:0% +okay +because it's the same equation so so the + + align:start position:0% +because it's the same equation so so the + + + align:start position:0% +because it's the same equation so so the +so the basis of equation of course is + + align:start position:0% +so the basis of equation of course is + + + align:start position:0% +so the basis of equation of course is +also the same as before yes + + align:start position:0% +also the same as before yes + + + align:start position:0% +also the same as before yes +this is an operator like doesn't it if + + align:start position:0% +this is an operator like doesn't it if + + + align:start position:0% +this is an operator like doesn't it if +it's an observable doesn't it have to be + + align:start position:0% +it's an observable doesn't it have to be + + + align:start position:0% +it's an observable doesn't it have to be +permission + + align:start position:0% +permission + + + align:start position:0% +permission +um no the field + + align:start position:0% +um no the field + + + align:start position:0% +um no the field +um it depends + + align:start position:0% +um it depends + + + align:start position:0% +um it depends +so + + align:start position:0% +so + + + align:start position:0% +so +um + + align:start position:0% +um + + + align:start position:0% +um +yeah indeed if it's a something directly + + align:start position:0% +yeah indeed if it's a something directly + + + align:start position:0% +yeah indeed if it's a something directly +observable uh has to be a remission but + + align:start position:0% +observable uh has to be a remission but + + + align:start position:0% +observable uh has to be a remission but +doesn't have two observables for example + + align:start position:0% +doesn't have two observables for example + + + align:start position:0% +doesn't have two observables for example +I can combine them into a real variable + + align:start position:0% +I can combine them into a real variable + + + align:start position:0% +I can combine them into a real variable +yeah + + align:start position:0% +yeah + + + align:start position:0% +yeah +yeah just not necessarily the fight + + align:start position:0% +yeah just not necessarily the fight + + + align:start position:0% +yeah just not necessarily the fight +itself having to be directory of the + + align:start position:0% +itself having to be directory of the + + + align:start position:0% +itself having to be directory of the +it's just a field + + align:start position:0% + + + + align:start position:0% + +yeah yeah the field itself don't have to + + align:start position:0% +yeah yeah the field itself don't have to + + + align:start position:0% +yeah yeah the field itself don't have to +always be observable by itself + + align:start position:0% + + + + align:start position:0% + +yeah + + align:start position:0% +yeah + + + align:start position:0% +yeah +this is not the momentum this is just + + align:start position:0% +this is not the momentum this is just + + + align:start position:0% +this is not the momentum this is just +the canonical momentum for the canonical + + align:start position:0% +the canonical momentum for the canonical + + + align:start position:0% +the canonical momentum for the canonical +organization right + + align:start position:0% +organization right + + + align:start position:0% +organization right +yeah + + align:start position:0% +yeah + + + align:start position:0% +yeah +yeah this is not the space-time momentum + + align:start position:0% +yeah this is not the space-time momentum + + + align:start position:0% +yeah this is not the space-time momentum +field operator the same thing as the + + align:start position:0% +field operator the same thing as the + + + align:start position:0% +field operator the same thing as the +pump as the star yeah here we are + + align:start position:0% +pump as the star yeah here we are + + + align:start position:0% +pump as the star yeah here we are +talking about the uh here we are talking + + align:start position:0% +talking about the uh here we are talking + + + align:start position:0% +talking about the uh here we are talking +about the classical Theory and then when + + align:start position:0% +about the classical Theory and then when + + + align:start position:0% +about the classical Theory and then when +we go to the quantum indeed we will + + align:start position:0% +we go to the quantum indeed we will + + + align:start position:0% +we go to the quantum indeed we will +replace the Star by by dagger yeah + + align:start position:0% + + + + align:start position:0% + +okay so now we can just write down the + + align:start position:0% +okay so now we can just write down the + + + align:start position:0% +okay so now we can just write down the +most General solutions to this equation + + align:start position:0% + + + + align:start position:0% + +okay now we can just write down the most + + align:start position:0% +okay now we can just write down the most + + + align:start position:0% +okay now we can just write down the most +General solution to this equation + + align:start position:0% +General solution to this equation + + + align:start position:0% +General solution to this equation +so we just + + align:start position:0% + + + + align:start position:0% + +so there's one slight difference from + + align:start position:0% +so there's one slight difference from + + + align:start position:0% +so there's one slight difference from +before almost the same identical as + + align:start position:0% +before almost the same identical as + + + align:start position:0% +before almost the same identical as +before + + align:start position:0% +before + + + align:start position:0% +before +except with one difference + + align:start position:0% + + + + align:start position:0% + +okay UK but here previously we have AK + + align:start position:0% +okay UK but here previously we have AK + + + align:start position:0% +okay UK but here previously we have AK +dagger + + align:start position:0% +dagger + + + align:start position:0% +dagger +okay we have a k star say classically + + align:start position:0% +okay we have a k star say classically + + + align:start position:0% +okay we have a k star say classically +let me just first write classically so + + align:start position:0% +let me just first write classically so + + + align:start position:0% +let me just first write classically so +previously we have this + + align:start position:0% +previously we have this + + + align:start position:0% +previously we have this +okay previously why we have a k star + + align:start position:0% +okay previously why we have a k star + + + align:start position:0% +okay previously why we have a k star +here when we have a real scalar field + + align:start position:0% + + + + align:start position:0% + +it's because the field has to be real + + align:start position:0% +it's because the field has to be real + + + align:start position:0% +it's because the field has to be real +and then we have always add to its + + align:start position:0% +and then we have always add to its + + + align:start position:0% +and then we have always add to its +complex conjugate okay but now the + + align:start position:0% +complex conjugate okay but now the + + + align:start position:0% +complex conjugate okay but now the +difference is that now Phi is a complex + + align:start position:0% +difference is that now Phi is a complex + + + align:start position:0% +difference is that now Phi is a complex +okay and the Phi is complex and then we + + align:start position:0% +okay and the Phi is complex and then we + + + align:start position:0% +okay and the Phi is complex and then we +no longer have the real condition the + + align:start position:0% +no longer have the real condition the + + + align:start position:0% +no longer have the real condition the +means here I can choose a ladder + + align:start position:0% +means here I can choose a ladder + + + align:start position:0% +means here I can choose a ladder +arbitrary constant here + + align:start position:0% +arbitrary constant here + + + align:start position:0% +arbitrary constant here +okay so this is the arbitrary constant + + align:start position:0% +okay so this is the arbitrary constant + + + align:start position:0% +okay so this is the arbitrary constant +so by convention let me just pull the + + align:start position:0% +so by convention let me just pull the + + + align:start position:0% +so by convention let me just pull the +star here okay it doesn't matter I just + + align:start position:0% +star here okay it doesn't matter I just + + + align:start position:0% +star here okay it doesn't matter I just +the name you call it okay so now the + + align:start position:0% +the name you call it okay so now the + + + align:start position:0% +the name you call it okay so now the +most General solution + + align:start position:0% +most General solution + + + align:start position:0% +most General solution +now you have two sets you have a which + + align:start position:0% +now you have two sets you have a which + + + align:start position:0% +now you have two sets you have a which +is complex number then you have another + + align:start position:0% +is complex number then you have another + + + align:start position:0% +is complex number then you have another +complex number which is p okay now you + + align:start position:0% +complex number which is p okay now you + + + align:start position:0% +complex number which is p okay now you +have two sets of complex numbers okay + + align:start position:0% +have two sets of complex numbers okay + + + align:start position:0% +have two sets of complex numbers okay +and it makes sense because when you have + + align:start position:0% +and it makes sense because when you have + + + align:start position:0% +and it makes sense because when you have +a complex variable you double the + + align:start position:0% +a complex variable you double the + + + align:start position:0% +a complex variable you double the +decrease freedom and your integration + + align:start position:0% +decrease freedom and your integration + + + align:start position:0% +decrease freedom and your integration +constant also doubled + + align:start position:0% +constant also doubled + + + align:start position:0% +constant also doubled +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so b k + + align:start position:0% + + + + align:start position:0% + +independent of a + + align:start position:0% + + + + align:start position:0% + +okay so now you have two sides of + + align:start position:0% +okay so now you have two sides of + + + align:start position:0% +okay so now you have two sides of +variables okay + + align:start position:0% + + + + align:start position:0% + +so you can get the five star just by + + align:start position:0% +so you can get the five star just by + + + align:start position:0% +so you can get the five star just by +taking the compared conjugate of it + + align:start position:0% +taking the compared conjugate of it + + + align:start position:0% +taking the compared conjugate of it +okay just by takes complex conjugate of + + align:start position:0% +okay just by takes complex conjugate of + + + align:start position:0% +okay just by takes complex conjugate of +it + + align:start position:0% +it + + + align:start position:0% +it +and then the four sets + + align:start position:0% + + + + align:start position:0% + +and then the full set of + + align:start position:0% + + + + align:start position:0% + +integration constant + + align:start position:0% + + + + align:start position:0% + +just you have a k + + align:start position:0% +just you have a k + + + align:start position:0% +just you have a k +you have AK star + + align:start position:0% +you have AK star + + + align:start position:0% +you have AK star +you have b k + + align:start position:0% +you have b k + + + align:start position:0% +you have b k +and then her BK stop + + align:start position:0% +and then her BK stop + + + align:start position:0% +and then her BK stop +okay so this is a classical story + + align:start position:0% + + + + align:start position:0% + +so now go to Quantum + + align:start position:0% + + + + align:start position:0% + +we just do exactly as we did before + + align:start position:0% +we just do exactly as we did before + + + align:start position:0% +we just do exactly as we did before +we just promoted all those into + + align:start position:0% +we just promoted all those into + + + align:start position:0% +we just promoted all those into +operating equations + + align:start position:0% +operating equations + + + align:start position:0% +operating equations +okay so so the uh so you just call the + + align:start position:0% +okay so so the uh so you just call the + + + align:start position:0% +okay so so the uh so you just call the +Stacker + + align:start position:0% +Stacker + + + align:start position:0% +Stacker +okay just call this diagram just view + + align:start position:0% +okay just call this diagram just view + + + align:start position:0% +okay just call this diagram just view +every of one of them as operators + + align:start position:0% +every of one of them as operators + + + align:start position:0% +every of one of them as operators +and now and now this just become + + align:start position:0% +and now and now this just become + + + align:start position:0% +and now and now this just become +constant operators + + align:start position:0% +constant operators + + + align:start position:0% +constant operators +and it becomes constant operators + + align:start position:0% +and it becomes constant operators + + + align:start position:0% +and it becomes constant operators +and now here you also just call them to + + align:start position:0% +and now here you also just call them to + + + align:start position:0% +and now here you also just call them to +be diagonal okay + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +and uh + + align:start position:0% +and uh + + + align:start position:0% +and uh +um yeah + + align:start position:0% + + + + align:start position:0% + +so now equal time correlation + + align:start position:0% +so now equal time correlation + + + align:start position:0% +so now equal time correlation +still we have to impose the equal time + + align:start position:0% + + + + align:start position:0% + +commutation relation + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% + + + + align:start position:0% + +so now we have to impose the equal time + + align:start position:0% +so now we have to impose the equal time + + + align:start position:0% +so now we have to impose the equal time +commutation relations + + align:start position:0% + + + + align:start position:0% + +again so these are should be + + align:start position:0% +again so these are should be + + + align:start position:0% +again so these are should be +simple so we should have Phi + + align:start position:0% +simple so we should have Phi + + + align:start position:0% +simple so we should have Phi +daggers they can they consider as + + align:start position:0% +daggers they can they consider as + + + align:start position:0% +daggers they can they consider as +independent operators that you should + + align:start position:0% +independent operators that you should + + + align:start position:0% +independent operators that you should +compute with each other they're all + + align:start position:0% +compute with each other they're all + + + align:start position:0% +compute with each other they're all +field variables + + align:start position:0% +field variables + + + align:start position:0% +field variables +and if I could commute itself + + align:start position:0% +and if I could commute itself + + + align:start position:0% +and if I could commute itself +so this is all evaluated at different + + align:start position:0% +so this is all evaluated at different + + + align:start position:0% +so this is all evaluated at different +spatial yeah just to save time I will + + align:start position:0% +spatial yeah just to save time I will + + + align:start position:0% +spatial yeah just to save time I will +not write this expressive but all this + + align:start position:0% +not write this expressive but all this + + + align:start position:0% +not write this expressive but all this +should be evaluated at the same time but + + align:start position:0% +should be evaluated at the same time but + + + align:start position:0% +should be evaluated at the same time but +different spatial locations okay + + align:start position:0% + + + + align:start position:0% + +such as all these equal to zero okay + + align:start position:0% +such as all these equal to zero okay + + + align:start position:0% +such as all these equal to zero okay +except the only thing which is non-zero + + align:start position:0% +except the only thing which is non-zero + + + align:start position:0% +except the only thing which is non-zero +is the five with its own + + align:start position:0% +is the five with its own + + + align:start position:0% +is the five with its own +canonical momentum okay + + align:start position:0% + + + + align:start position:0% + +so everything else will be zero the only + + align:start position:0% +so everything else will be zero the only + + + align:start position:0% +so everything else will be zero the only +thing on zero is Phi + + align:start position:0% + + + + align:start position:0% + +which is canonical momentum + + align:start position:0% + + + + align:start position:0% + +again should be given by I Delta 3 + + align:start position:0% +again should be given by I Delta 3 + + + align:start position:0% +again should be given by I Delta 3 +x minus X Prime + + align:start position:0% +x minus X Prime + + + align:start position:0% +x minus X Prime +and then then the similar scene for the + + align:start position:0% +and then then the similar scene for the + + + align:start position:0% +and then then the similar scene for the +fat diagram okay + + align:start position:0% + + + + align:start position:0% + +okay so again I say a effort okay + + align:start position:0% +okay so again I say a effort okay + + + align:start position:0% +okay so again I say a effort okay +so so uh so that's what you should + + align:start position:0% +so so uh so that's what you should + + + align:start position:0% +so so uh so that's what you should +impose + + align:start position:0% + + + + align:start position:0% + +so now if you plug those things in + + align:start position:0% +so now if you plug those things in + + + align:start position:0% +so now if you plug those things in +then then you can find the uh a + + align:start position:0% +then then you can find the uh a + + + align:start position:0% +then then you can find the uh a +commutation relation between a and a + + align:start position:0% +commutation relation between a and a + + + align:start position:0% +commutation relation between a and a +dagger + + align:start position:0% + + + + align:start position:0% + +then again you find + + align:start position:0% + + + + align:start position:0% + +and similarly with speed + + align:start position:0% +and similarly with speed + + + align:start position:0% +and similarly with speed +you just get now two two sides of two + + align:start position:0% +you just get now two two sides of two + + + align:start position:0% +you just get now two two sides of two +infinite family of harmonic oscillators + + align:start position:0% +infinite family of harmonic oscillators + + + align:start position:0% +infinite family of harmonic oscillators +okay previously we have one family and + + align:start position:0% +okay previously we have one family and + + + align:start position:0% +okay previously we have one family and +now you get two two families okay and + + align:start position:0% +now you get two two families okay and + + + align:start position:0% +now you get two two families okay and +and all other commentates vanish + + align:start position:0% + + + + align:start position:0% + +so so this part is boring you can almost + + align:start position:0% +so so this part is boring you can almost + + + align:start position:0% +so so this part is boring you can almost +guess any gas everything + + align:start position:0% +guess any gas everything + + + align:start position:0% +guess any gas everything +without doing any calculation + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +when essentially cast everything without + + align:start position:0% +when essentially cast everything without + + + align:start position:0% +when essentially cast everything without +doing any calculation + + align:start position:0% + + + + align:start position:0% + +so now again you can write the + + align:start position:0% +so now again you can write the + + + align:start position:0% +so now again you can write the +hamiltonian in terms of AK and B K okay + + align:start position:0% +hamiltonian in terms of AK and B K okay + + + align:start position:0% +hamiltonian in terms of AK and B K okay +just will be as you would guess them to + + align:start position:0% +just will be as you would guess them to + + + align:start position:0% +just will be as you would guess them to +be okay uh uh just the harmonic + + align:start position:0% +be okay uh uh just the harmonic + + + align:start position:0% +be okay uh uh just the harmonic +alternator that corresponding to 8K + + align:start position:0% +alternator that corresponding to 8K + + + align:start position:0% +alternator that corresponding to 8K +harmonic acid corresponding to BK okay + + align:start position:0% + + + + align:start position:0% + +so and then the uh and then the ground + + align:start position:0% +so and then the uh and then the ground + + + align:start position:0% +so and then the uh and then the ground +state again + + align:start position:0% +state again + + + align:start position:0% +state again +is the op + + align:start position:0% +is the op + + + align:start position:0% +is the op +is the state related by both of them + + align:start position:0% + + + + align:start position:0% + +okay so this is the vacuum state + + align:start position:0% + + + + align:start position:0% + +and now you can act + + align:start position:0% +and now you can act + + + align:start position:0% +and now you can act +AK dagger on zero + + align:start position:0% +AK dagger on zero + + + align:start position:0% +AK dagger on zero +and BK diagram 0. + + align:start position:0% + + + + align:start position:0% + +Etc okay + + align:start position:0% + + + + align:start position:0% + +so now we have two kinds of particles + + align:start position:0% + + + + align:start position:0% + +so now we have two final particles + + align:start position:0% + + + + align:start position:0% + +generated + + align:start position:0% + + + + align:start position:0% + +by AK dagger + + align:start position:0% + + + + align:start position:0% + +and BK dagger now okay + + align:start position:0% +and BK dagger now okay + + + align:start position:0% +and BK dagger now okay +so now you have two kind of bad + + align:start position:0% +so now you have two kind of bad + + + align:start position:0% +so now you have two kind of bad +respectively + + align:start position:0% + + + + align:start position:0% + +and both of them have the same + + align:start position:0% + + + + align:start position:0% + +unsure condition okay both both + + align:start position:0% +unsure condition okay both both + + + align:start position:0% +unsure condition okay both both +particles + + align:start position:0% +particles + + + align:start position:0% +particles +have the same mass + + align:start position:0% +have the same mass + + + align:start position:0% +have the same mass +they satisfy the P-Square equal to M + + align:start position:0% +they satisfy the P-Square equal to M + + + align:start position:0% +they satisfy the P-Square equal to M +squared + + align:start position:0% + + + + align:start position:0% + +minus M Square okay + + align:start position:0% +minus M Square okay + + + align:start position:0% +minus M Square okay +so because they all come from the same + + align:start position:0% +so because they all come from the same + + + align:start position:0% +so because they all come from the same +equation + + align:start position:0% +equation + + + align:start position:0% +equation +okay + + align:start position:0% + + + + align:start position:0% + +so now the question is how do we tell + + align:start position:0% +so now the question is how do we tell + + + align:start position:0% +so now the question is how do we tell +them apart + + align:start position:0% +them apart + + + align:start position:0% +them apart +okay now we have two type of particles + + align:start position:0% +okay now we have two type of particles + + + align:start position:0% +okay now we have two type of particles +they they have the same mass + + align:start position:0% +they they have the same mass + + + align:start position:0% +they they have the same mass +and we + + align:start position:0% +and we + + + align:start position:0% +and we +yeah just by definition they don't have + + align:start position:0% +yeah just by definition they don't have + + + align:start position:0% +yeah just by definition they don't have +any + + align:start position:0% +any + + + align:start position:0% +any +they have same mass they all have the + + align:start position:0% +they have same mass they all have the + + + align:start position:0% +they have same mass they all have the +same spin because they're all spin zero + + align:start position:0% +same spin because they're all spin zero + + + align:start position:0% +same spin because they're all spin zero +scalar particles there's no no + + align:start position:0% +scalar particles there's no no + + + align:start position:0% +scalar particles there's no no +directions okay + + align:start position:0% +directions okay + + + align:start position:0% +directions okay +and uh uh um yeah the question how do we + + align:start position:0% +and uh uh um yeah the question how do we + + + align:start position:0% +and uh uh um yeah the question how do we +tell them apart + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +foreign + + align:start position:0% + + + + align:start position:0% + +useful + + align:start position:0% + + + + align:start position:0% + +okay here is this U1 symmet to become + + align:start position:0% +okay here is this U1 symmet to become + + + align:start position:0% +okay here is this U1 symmet to become +useful + + align:start position:0% +useful + + + align:start position:0% +useful +so this UI so so this phase rotation + + align:start position:0% + + + + align:start position:0% + +so this phase rotation is a symmetry + + align:start position:0% +so this phase rotation is a symmetry + + + align:start position:0% +so this phase rotation is a symmetry +and mathematically this is called the U1 + + align:start position:0% +and mathematically this is called the U1 + + + align:start position:0% +and mathematically this is called the U1 +transformation + + align:start position:0% +transformation + + + align:start position:0% +transformation +okay so this is called normally called + + align:start position:0% +okay so this is called normally called + + + align:start position:0% +okay so this is called normally called +the U1 cb3 + + align:start position:0% +the U1 cb3 + + + align:start position:0% +the U1 cb3 +you want just a mathematical term + + align:start position:0% +you want just a mathematical term + + + align:start position:0% +you want just a mathematical term +for for phase rotation okay a + + align:start position:0% +for for phase rotation okay a + + + align:start position:0% +for for phase rotation okay a +mathematically it's a U1 group it's a + + align:start position:0% +mathematically it's a U1 group it's a + + + align:start position:0% +mathematically it's a U1 group it's a +mathematical term for uh for um + + align:start position:0% + + + + align:start position:0% + +so so the way we take them apart is by + + align:start position:0% +so so the way we take them apart is by + + + align:start position:0% +so so the way we take them apart is by +looking at their conserved number and + + align:start position:0% +looking at their conserved number and + + + align:start position:0% +looking at their conserved number and +look at their quantum numbers okay if we + + align:start position:0% +look at their quantum numbers okay if we + + + align:start position:0% +look at their quantum numbers okay if we +look at two particles so how do we tell + + align:start position:0% +look at two particles so how do we tell + + + align:start position:0% +look at two particles so how do we tell +them apart we look at the quantum + + align:start position:0% +them apart we look at the quantum + + + align:start position:0% +them apart we look at the quantum +numbers + + align:start position:0% +numbers + + + align:start position:0% +numbers +and they're quantum numbers so far they + + align:start position:0% +and they're quantum numbers so far they + + + align:start position:0% +and they're quantum numbers so far they +look almost the same because their mass + + align:start position:0% +look almost the same because their mass + + + align:start position:0% +look almost the same because their mass +is the same + + align:start position:0% +is the same + + + align:start position:0% +is the same +and by definition their scale of + + align:start position:0% +and by definition their scale of + + + align:start position:0% +and by definition their scale of +particles and so they have zeros their + + align:start position:0% +particles and so they have zeros their + + + align:start position:0% +particles and so they have zeros their +spin zero they don't have spin + + align:start position:0% +spin zero they don't have spin + + + align:start position:0% +spin zero they don't have spin +and so the only other conserved number + + align:start position:0% +and so the only other conserved number + + + align:start position:0% +and so the only other conserved number +uh yeah if you want to talk about + + align:start position:0% +uh yeah if you want to talk about + + + align:start position:0% +uh yeah if you want to talk about +quantum number the quantum number has + + align:start position:0% +quantum number the quantum number has + + + align:start position:0% +quantum number the quantum number has +got to be conserved okay because + + align:start position:0% +got to be conserved okay because + + + align:start position:0% +got to be conserved okay because +otherwise if it changes with time it + + align:start position:0% +otherwise if it changes with time it + + + align:start position:0% +otherwise if it changes with time it +doesn't matter it doesn't make sense to + + align:start position:0% +doesn't matter it doesn't make sense to + + + align:start position:0% +doesn't matter it doesn't make sense to +to use that number to label a particle + + align:start position:0% +to use that number to label a particle + + + align:start position:0% +to use that number to label a particle +but we get one more kind of number uh + + align:start position:0% +but we get one more kind of number uh + + + align:start position:0% +but we get one more kind of number uh +corresponding to the uh to this symmetry + + align:start position:0% +corresponding to the uh to this symmetry + + + align:start position:0% +corresponding to the uh to this symmetry +okay so so this UI symmetry + + align:start position:0% +okay so so this UI symmetry + + + align:start position:0% +okay so so this UI symmetry +it's an also theorem + + align:start position:0% + + + + align:start position:0% + +yeah from the law system so this is one + + align:start position:0% +yeah from the law system so this is one + + + align:start position:0% +yeah from the law system so this is one +symmetry + + align:start position:0% + + + + align:start position:0% + +charge + + align:start position:0% +charge + + + align:start position:0% +charge +so if you work it out + + align:start position:0% +so if you work it out + + + align:start position:0% +so if you work it out +you work out the loss of theorem then + + align:start position:0% +you work out the loss of theorem then + + + align:start position:0% +you work out the loss of theorem then +you find it's the the corresponding + + align:start position:0% +you find it's the the corresponding + + + align:start position:0% +you find it's the the corresponding +conserved charge which you should have + + align:start position:0% +conserved charge which you should have + + + align:start position:0% +conserved charge which you should have +already worked out + + align:start position:0% +already worked out + + + align:start position:0% +already worked out +so let me just write it classically + + align:start position:0% +so let me just write it classically + + + align:start position:0% +so let me just write it classically +so as I just write them as five star + + align:start position:0% +so as I just write them as five star + + + align:start position:0% +so as I just write them as five star +so classically they have the following + + align:start position:0% +so classically they have the following + + + align:start position:0% +so classically they have the following +form okay + + align:start position:0% + + + + align:start position:0% + +so the quantum level this becomes + + align:start position:0% +so the quantum level this becomes + + + align:start position:0% +so the quantum level this becomes +operators + + align:start position:0% + + + + align:start position:0% + +but here there's a operator and a + + align:start position:0% +but here there's a operator and a + + + align:start position:0% +but here there's a operator and a +but now here this operator uh uh uh when + + align:start position:0% +but now here this operator uh uh uh when + + + align:start position:0% +but now here this operator uh uh uh when +we go to the quantum level + + align:start position:0% +we go to the quantum level + + + align:start position:0% +we go to the quantum level +now there's the operator ordering + + align:start position:0% +now there's the operator ordering + + + align:start position:0% +now there's the operator ordering +ambiguity now + + align:start position:0% +ambiguity now + + + align:start position:0% +ambiguity now +you see uh here + + align:start position:0% +you see uh here + + + align:start position:0% +you see uh here +the Phi + + align:start position:0% +the Phi + + + align:start position:0% +the Phi +don't commute with its own a conjugate + + align:start position:0% +don't commute with its own a conjugate + + + align:start position:0% +don't commute with its own a conjugate +momentum okay + + align:start position:0% +momentum okay + + + align:start position:0% +momentum okay +and so here we have five multiplied + + align:start position:0% +and so here we have five multiplied + + + align:start position:0% +and so here we have five multiplied +conjugate momentum + + align:start position:0% +conjugate momentum + + + align:start position:0% +conjugate momentum +and if we change the order + + align:start position:0% +and if we change the order + + + align:start position:0% +and if we change the order +and then we build a result a data + + align:start position:0% +and then we build a result a data + + + align:start position:0% +and then we build a result a data +function + + align:start position:0% +function + + + align:start position:0% +function +can we build without the data function + + align:start position:0% +can we build without the data function + + + align:start position:0% +can we build without the data function +okay and and that will give rise to + + align:start position:0% +okay and and that will give rise to + + + align:start position:0% +okay and and that will give rise to +infinite uh uh yeah so + + align:start position:0% + + + + align:start position:0% + +at Quantum level + + align:start position:0% + + + + align:start position:0% + +different ordering + + align:start position:0% + + + + align:start position:0% + +differ + + align:start position:0% + + + + align:start position:0% + +my + + align:start position:0% +my + + + align:start position:0% +my +some + + align:start position:0% + + + + align:start position:0% + +infinite constant + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +so you can take five uh you can yeah if + + align:start position:0% +so you can take five uh you can yeah if + + + align:start position:0% +so you can take five uh you can yeah if +you change order in them then you get a + + align:start position:0% +you change order in them then you get a + + + align:start position:0% +you change order in them then you get a +Delta function but that function again + + align:start position:0% +Delta function but that function again + + + align:start position:0% +Delta function but that function again +is evaluated + + align:start position:0% +is evaluated + + + align:start position:0% +is evaluated +big because these two is a divided at + + align:start position:0% +big because these two is a divided at + + + align:start position:0% +big because these two is a divided at +the same X and then you get the data + + align:start position:0% +the same X and then you get the data + + + align:start position:0% +the same X and then you get the data +function values at the zero okay so + + align:start position:0% +function values at the zero okay so + + + align:start position:0% +function values at the zero okay so +essentially you get the infinite + + align:start position:0% +essentially you get the infinite + + + align:start position:0% +essentially you get the infinite +constant + + align:start position:0% + + + + align:start position:0% + +but we can fix this ambiguity + + align:start position:0% +but we can fix this ambiguity + + + align:start position:0% +but we can fix this ambiguity +okay we can fix this ambiguity + + align:start position:0% + + + + align:start position:0% + +by requiring + + align:start position:0% + + + + align:start position:0% + +your vacuum State your lowest energy + + align:start position:0% +your vacuum State your lowest energy + + + align:start position:0% +your vacuum State your lowest energy +state + + align:start position:0% +state + + + align:start position:0% +state +should have charge zero + + align:start position:0% +should have charge zero + + + align:start position:0% +should have charge zero +okay because it's a bad definition when + + align:start position:0% +okay because it's a bad definition when + + + align:start position:0% +okay because it's a bad definition when +you add lowest energy there's nothing + + align:start position:0% +you add lowest energy there's nothing + + + align:start position:0% +you add lowest energy there's nothing +there okay it's a vacuum + + align:start position:0% +there okay it's a vacuum + + + align:start position:0% +there okay it's a vacuum +by requiring the lowest energy State + + align:start position:0% +by requiring the lowest energy State + + + align:start position:0% +by requiring the lowest energy State +have charge to zero + + align:start position:0% +have charge to zero + + + align:start position:0% +have charge to zero +okay so that uniquely fix whatever or + + align:start position:0% +okay so that uniquely fix whatever or + + + align:start position:0% +okay so that uniquely fix whatever or +infinite + + align:start position:0% +infinite + + + align:start position:0% +infinite +the ordering + + align:start position:0% +the ordering + + + align:start position:0% +the ordering +so so by this equal to zero + + align:start position:0% +so so by this equal to zero + + + align:start position:0% +so so by this equal to zero +and then you can show that the Q + + align:start position:0% +and then you can show that the Q + + + align:start position:0% +and then you can show that the Q +so now you can essentially + + align:start position:0% +so now you can essentially + + + align:start position:0% +so now you can essentially +the queue have the following form + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so you can already you may be able to + + align:start position:0% +so you can already you may be able to + + + align:start position:0% +so you can already you may be able to +guess the answer + + align:start position:0% +guess the answer + + + align:start position:0% +guess the answer +AK + + align:start position:0% +AK + + + align:start position:0% +AK +a AK + + align:start position:0% +a AK + + + align:start position:0% +a AK +the manners + + align:start position:0% +the manners + + + align:start position:0% +the manners +BK dagger + + align:start position:0% +BK dagger + + + align:start position:0% +BK dagger +UK + + align:start position:0% +UK + + + align:start position:0% +UK +okay that's what you get okay + + align:start position:0% +okay that's what you get okay + + + align:start position:0% +okay that's what you get okay +so you plug those expressions in + + align:start position:0% + + + + align:start position:0% + +you plug those expression like this time + + align:start position:0% +you plug those expression like this time + + + align:start position:0% +you plug those expression like this time +derivative okay time is derivative view + + align:start position:0% +derivative okay time is derivative view + + + align:start position:0% +derivative okay time is derivative view +Pi you just plug those expression in + + align:start position:0% +Pi you just plug those expression in + + + align:start position:0% +Pi you just plug those expression in +and again you will find because this is + + align:start position:0% +and again you will find because this is + + + align:start position:0% +and again you will find because this is +conserved you find all this time + + align:start position:0% +conserved you find all this time + + + align:start position:0% +conserved you find all this time +dependence cancel Etc + + align:start position:0% +dependence cancel Etc + + + align:start position:0% +dependence cancel Etc +and then you get these two expressions + + align:start position:0% +and then you get these two expressions + + + align:start position:0% +and then you get these two expressions +up to some constant + + align:start position:0% +up to some constant + + + align:start position:0% +up to some constant +okay and then and then this condition + + align:start position:0% +okay and then and then this condition + + + align:start position:0% +okay and then and then this condition +requires that that constant must be zero + + align:start position:0% +requires that that constant must be zero + + + align:start position:0% +requires that that constant must be zero +okay yeah when you write in this form + + align:start position:0% +okay yeah when you write in this form + + + align:start position:0% +okay yeah when you write in this form +okay + + align:start position:0% +okay + + + align:start position:0% +okay +you see this violates the Q because the + + align:start position:0% +you see this violates the Q because the + + + align:start position:0% +you see this violates the Q because the +a is on the right hand side of a dagger + + align:start position:0% +a is on the right hand side of a dagger + + + align:start position:0% +a is on the right hand side of a dagger +so this automatically allows the vacuum + + align:start position:0% + + + + align:start position:0% + +so essentially this is just occupation + + align:start position:0% +so essentially this is just occupation + + + align:start position:0% +so essentially this is just occupation +number + + align:start position:0% +number + + + align:start position:0% +number +for a and this occupation number for b k + + align:start position:0% +for a and this occupation number for b k + + + align:start position:0% +for a and this occupation number for b k +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so we essentially + + align:start position:0% + + + + align:start position:0% + +so we essentially get Q + + align:start position:0% + + + + align:start position:0% + +essentially the occupation number + + align:start position:0% +essentially the occupation number + + + align:start position:0% +essentially the occupation number +for a k + + align:start position:0% +for a k + + + align:start position:0% +for a k +and the occupation number for b k + + align:start position:0% +and the occupation number for b k + + + align:start position:0% +and the occupation number for b k +okay so occupation number just write as + + align:start position:0% +okay so occupation number just write as + + + align:start position:0% +okay so occupation number just write as +n okay + + align:start position:0% +n okay + + + align:start position:0% +n okay +yes + + align:start position:0% + + + + align:start position:0% + +if you switch them you still get pissing + + align:start position:0% +if you switch them you still get pissing + + + align:start position:0% +if you switch them you still get pissing +issues + + align:start position:0% +issues + + + align:start position:0% +issues +but if you create them you still get the + + align:start position:0% +but if you create them you still get the + + + align:start position:0% +but if you create them you still get the +infinite Constance on fused why this + + align:start position:0% +infinite Constance on fused why this + + + align:start position:0% +infinite Constance on fused why this +is considered effective no the one you + + align:start position:0% +is considered effective no the one you + + + align:start position:0% +is considered effective no the one you +permute them then you no longer rally + + align:start position:0% +permute them then you no longer rally + + + align:start position:0% +permute them then you no longer rally +the vacuum right so that constant will + + align:start position:0% +the vacuum right so that constant will + + + align:start position:0% +the vacuum right so that constant will +cancel + + align:start position:0% +cancel + + + align:start position:0% +cancel +so only this form with a is sitting on + + align:start position:0% +so only this form with a is sitting on + + + align:start position:0% +so only this form with a is sitting on +the right hand side of a dagger this + + align:start position:0% +the right hand side of a dagger this + + + align:start position:0% +the right hand side of a dagger this +will violate the vacuum + + align:start position:0% + + + + align:start position:0% + +okay I guess like because earlier you + + align:start position:0% +okay I guess like because earlier you + + + align:start position:0% +okay I guess like because earlier you +the line of argument was if you permit + + align:start position:0% +the line of argument was if you permit + + + align:start position:0% +the line of argument was if you permit +them yeah + + align:start position:0% +them yeah + + + align:start position:0% +them yeah +you would get the same thing here right + + align:start position:0% +you would get the same thing here right + + + align:start position:0% +you would get the same thing here right +if you create them you also no no no + + align:start position:0% +if you create them you also no no no + + + align:start position:0% +if you create them you also no no no +no no + + align:start position:0% +no no + + + align:start position:0% +no no +here here there's ambiguity + + align:start position:0% +here here there's ambiguity + + + align:start position:0% +here here there's ambiguity +here I don't know how I should order + + align:start position:0% +here I don't know how I should order + + + align:start position:0% +here I don't know how I should order +them + + align:start position:0% +them + + + align:start position:0% +them +whether I should put 5 to the right of + + align:start position:0% +whether I should put 5 to the right of + + + align:start position:0% +whether I should put 5 to the right of +Pi or put pi to the left to the right of + + align:start position:0% +Pi or put pi to the left to the right of + + + align:start position:0% +Pi or put pi to the left to the right of +five I'm not sure how should I do + + align:start position:0% +five I'm not sure how should I do + + + align:start position:0% +five I'm not sure how should I do +okay here there's no prescription + + align:start position:0% +okay here there's no prescription + + + align:start position:0% +okay here there's no prescription +and uh uh uh uh here there's no + + align:start position:0% +and uh uh uh uh here there's no + + + align:start position:0% +and uh uh uh uh here there's no +prescription but if I impose this + + align:start position:0% +prescription but if I impose this + + + align:start position:0% +prescription but if I impose this +condition + + align:start position:0% +condition + + + align:start position:0% +condition +okay then that 40 then that tells you + + align:start position:0% +okay then that 40 then that tells you + + + align:start position:0% +okay then that 40 then that tells you +when I impose this condition then Q must + + align:start position:0% +when I impose this condition then Q must + + + align:start position:0% +when I impose this condition then Q must +be of this form + + align:start position:0% + + + + align:start position:0% + +okay must be of this form of course when + + align:start position:0% +okay must be of this form of course when + + + align:start position:0% +okay must be of this form of course when +you permute them it's the same thing we + + align:start position:0% +you permute them it's the same thing we + + + align:start position:0% +you permute them it's the same thing we +inform you then you don't change the + + align:start position:0% +inform you then you don't change the + + + align:start position:0% +inform you then you don't change the +operator + + align:start position:0% +operator + + + align:start position:0% +operator +you don't change the operator yeah but + + align:start position:0% +you don't change the operator yeah but + + + align:start position:0% +you don't change the operator yeah but +but if you do say let's do this order + + align:start position:0% + + + + align:start position:0% + +if you do this order + + align:start position:0% +if you do this order + + + align:start position:0% +if you do this order +what you get is this expression with the + + align:start position:0% +what you get is this expression with the + + + align:start position:0% +what you get is this expression with the +infinite constant + + align:start position:0% +infinite constant + + + align:start position:0% +infinite constant +and then this condition tells you + + align:start position:0% +and then this condition tells you + + + align:start position:0% +and then this condition tells you +somehow you have to change your order + + align:start position:0% +somehow you have to change your order + + + align:start position:0% +somehow you have to change your order +here so that that constant is zero okay + + align:start position:0% + + + + align:start position:0% + +yeah when you write it in this form when + + align:start position:0% +yeah when you write it in this form when + + + align:start position:0% +yeah when you write it in this form when +you write it in A and B and that + + align:start position:0% +you write it in A and B and that + + + align:start position:0% +you write it in A and B and that +constant has to be zero + + align:start position:0% +constant has to be zero + + + align:start position:0% +constant has to be zero +yes + + align:start position:0% +yes + + + align:start position:0% +yes +the ordering ambiguity how many physical + + align:start position:0% +the ordering ambiguity how many physical + + + align:start position:0% +the ordering ambiguity how many physical +consequences because + + align:start position:0% +consequences because + + + align:start position:0% +consequences because +um besides just things that can be + + align:start position:0% +um besides just things that can be + + + align:start position:0% +um besides just things that can be +subtracted off + + align:start position:0% +subtracted off + + + align:start position:0% +subtracted off +yeah yeah it's it's a + + align:start position:0% +yeah yeah it's it's a + + + align:start position:0% +yeah yeah it's it's a +yeah this is a a good question which + + align:start position:0% +yeah this is a a good question which + + + align:start position:0% +yeah this is a a good question which +it's hard to say so so most of the time + + align:start position:0% +it's hard to say so so most of the time + + + align:start position:0% +it's hard to say so so most of the time +you can fix them + + align:start position:0% +you can fix them + + + align:start position:0% +you can fix them +based on physical environment uh + + align:start position:0% +based on physical environment uh + + + align:start position:0% +based on physical environment uh +benefits yeah as here you can fix it + + align:start position:0% +benefits yeah as here you can fix it + + + align:start position:0% +benefits yeah as here you can fix it +based on physical requirement and then + + align:start position:0% +based on physical requirement and then + + + align:start position:0% +based on physical requirement and then +you don't have to worry about it anymore + + align:start position:0% +you don't have to worry about it anymore + + + align:start position:0% +you don't have to worry about it anymore +but but + + align:start position:0% +but but + + + align:start position:0% +but but +the ordinal ambiguity requires you try + + align:start position:0% +the ordinal ambiguity requires you try + + + align:start position:0% +the ordinal ambiguity requires you try +to find such a physical requirement + + align:start position:0% +to find such a physical requirement + + + align:start position:0% +to find such a physical requirement +yeah yeah because otherwise uh what + + align:start position:0% +yeah yeah because otherwise uh what + + + align:start position:0% +yeah yeah because otherwise uh what +ordering should you use and the process + + align:start position:0% +ordering should you use and the process + + + align:start position:0% +ordering should you use and the process +of finding that requirement by itself is + + align:start position:0% +of finding that requirement by itself is + + + align:start position:0% +of finding that requirement by itself is +understanding the physics + + align:start position:0% + + + + align:start position:0% + +yes when you got the infinite energy and + + align:start position:0% +yes when you got the infinite energy and + + + align:start position:0% +yes when you got the infinite energy and +the previous lecture because now + + align:start position:0% +the previous lecture because now + + + align:start position:0% +the previous lecture because now +required the round state to have like + + align:start position:0% +required the round state to have like + + + align:start position:0% +required the round state to have like +zero energy and then get some different + + align:start position:0% +zero energy and then get some different + + + align:start position:0% +zero energy and then get some different +ordering right no in that case uh we + + align:start position:0% +ordering right no in that case uh we + + + align:start position:0% +ordering right no in that case uh we +don't have other ambiguity + + align:start position:0% +don't have other ambiguity + + + align:start position:0% +don't have other ambiguity +so in that case because we just have + + align:start position:0% +so in that case because we just have + + + align:start position:0% +so in that case because we just have +Pi Square + + align:start position:0% +Pi Square + + + align:start position:0% +Pi Square +itself Plus + + align:start position:0% +itself Plus + + + align:start position:0% +itself Plus +5 square and plus 5 squared there's no + + align:start position:0% +5 square and plus 5 squared there's no + + + align:start position:0% +5 square and plus 5 squared there's no +ordering ambiguity here + + align:start position:0% +ordering ambiguity here + + + align:start position:0% +ordering ambiguity here +and so so whatever you get is whatever + + align:start position:0% +and so so whatever you get is whatever + + + align:start position:0% +and so so whatever you get is whatever +you get + + align:start position:0% +you get + + + align:start position:0% +you get +and if you get infinite constant then + + align:start position:0% +and if you get infinite constant then + + + align:start position:0% +and if you get infinite constant then +you get infinite constant now you don't + + align:start position:0% +you get infinite constant now you don't + + + align:start position:0% +you get infinite constant now you don't +have freedom yeah + + align:start position:0% + + + + align:start position:0% + +other questions + + align:start position:0% +other questions + + + align:start position:0% +other questions +yes + + align:start position:0% + + + + align:start position:0% + +clear that they can like how do you know + + align:start position:0% +clear that they can like how do you know + + + align:start position:0% +clear that they can like how do you know +that there's no coupling between the + + align:start position:0% +that there's no coupling between the + + + align:start position:0% +that there's no coupling between the +fields oh how do you represent it and oh + + align:start position:0% +fields oh how do you represent it and oh + + + align:start position:0% +fields oh how do you represent it and oh +oh this is a definition uh you say where + + align:start position:0% +oh this is a definition uh you say where + + + align:start position:0% +oh this is a definition uh you say where +this come from + + align:start position:0% + + + + align:start position:0% + +yeah yeah this is just a definition + + align:start position:0% +yeah yeah this is just a definition + + + align:start position:0% +yeah yeah this is just a definition +off of the this is the same uh + + align:start position:0% +off of the this is the same uh + + + align:start position:0% +off of the this is the same uh +this night have nothing to do with field + + align:start position:0% +this night have nothing to do with field + + + align:start position:0% +this night have nothing to do with field +series only this equation have to do + + align:start position:0% +series only this equation have to do + + + align:start position:0% +series only this equation have to do +with sphere Theory this I have nothing + + align:start position:0% +with sphere Theory this I have nothing + + + align:start position:0% +with sphere Theory this I have nothing +to do with filtering this is just + + align:start position:0% +to do with filtering this is just + + + align:start position:0% +to do with filtering this is just +quantum mechanics that differently + + align:start position:0% +quantum mechanics that differently + + + align:start position:0% +quantum mechanics that differently +different because Freedom they compute + + align:start position:0% +different because Freedom they compute + + + align:start position:0% +different because Freedom they compute +with each other yeah just X One commute + + align:start position:0% +with each other yeah just X One commute + + + align:start position:0% +with each other yeah just X One commute +with x2 in quantum mechanics yeah five + + align:start position:0% +with x2 in quantum mechanics yeah five + + + align:start position:0% +with x2 in quantum mechanics yeah five +here just five and five diagramages it's + + align:start position:0% +here just five and five diagramages it's + + + align:start position:0% +here just five and five diagramages it's +analog of x y and X2 there + + align:start position:0% + + + + align:start position:0% + +other questions + + align:start position:0% + + + + align:start position:0% + +um no it's different from that here + + align:start position:0% +um no it's different from that here + + + align:start position:0% +um no it's different from that here +here it just means that the uh here you + + align:start position:0% +here it just means that the uh here you + + + align:start position:0% +here it just means that the uh here you +should view them as the variables in the + + align:start position:0% +should view them as the variables in the + + + align:start position:0% +should view them as the variables in the +configuration space and uh it's just the + + align:start position:0% +configuration space and uh it's just the + + + align:start position:0% +configuration space and uh it's just the +in quantum mechanics the worry was a + + align:start position:0% +in quantum mechanics the worry was a + + + align:start position:0% +in quantum mechanics the worry was a +configuration space they always commute + + align:start position:0% +configuration space they always commute + + + align:start position:0% +configuration space they always commute +with each other + + align:start position:0% +with each other + + + align:start position:0% +with each other +foreign + + align:start position:0% +foreign + + + align:start position:0% +foreign +[Applause] + + align:start position:0% + + + + align:start position:0% + +so now the key thing is that here is the + + align:start position:0% +so now the key thing is that here is the + + + align:start position:0% +so now the key thing is that here is the +minus sign + + align:start position:0% +minus sign + + + align:start position:0% +minus sign +so that means + + align:start position:0% +so that means + + + align:start position:0% +so that means +when you look at the commutator between + + align:start position:0% +when you look at the commutator between + + + align:start position:0% +when you look at the commutator between +Q and A + + align:start position:0% + + + + align:start position:0% + +you get the a + + align:start position:0% +you get the a + + + align:start position:0% +you get the a +and if you look at the commutative a we + + align:start position:0% +and if you look at the commutative a we + + + align:start position:0% +and if you look at the commutative a we +speak a + + align:start position:0% +speak a + + + align:start position:0% +speak a +you actually get a minus BK + + align:start position:0% +you actually get a minus BK + + + align:start position:0% +you actually get a minus BK +okay you get + + align:start position:0% +okay you get + + + align:start position:0% +okay you get +yeah let me just do the diagram because + + align:start position:0% +yeah let me just do the diagram because + + + align:start position:0% +yeah let me just do the diagram because +the + + align:start position:0% +the + + + align:start position:0% +the +because this is used to create particle + + align:start position:0% +because this is used to create particle + + + align:start position:0% +because this is used to create particle +okay + + align:start position:0% + + + + align:start position:0% + +so if you just calculate the commutator + + align:start position:0% +so if you just calculate the commutator + + + align:start position:0% +so if you just calculate the commutator +we just find that + + align:start position:0% + + + + align:start position:0% + +so that means + + align:start position:0% + + + + align:start position:0% + +that means + + align:start position:0% + + + + align:start position:0% + +if you look at the um + + align:start position:0% +if you look at the um + + + align:start position:0% +if you look at the um +States defined by + + align:start position:0% + + + + align:start position:0% + +one particle State corresponding to a + + align:start position:0% +one particle State corresponding to a + + + align:start position:0% +one particle State corresponding to a +and the one particle State corresponding + + align:start position:0% +and the one particle State corresponding + + + align:start position:0% +and the one particle State corresponding +to B + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +then then both are acting vectors of Q + + align:start position:0% +then then both are acting vectors of Q + + + align:start position:0% +then then both are acting vectors of Q +but with ch but here with eigenvalue one + + align:start position:0% +but with ch but here with eigenvalue one + + + align:start position:0% +but with ch but here with eigenvalue one +but this one is eigenvalue minus one + + align:start position:0% +but this one is eigenvalue minus one + + + align:start position:0% +but this one is eigenvalue minus one +okay so it means they actually have + + align:start position:0% +okay so it means they actually have + + + align:start position:0% +okay so it means they actually have +opposite charge + + align:start position:0% + + + + align:start position:0% + +Okay so + + align:start position:0% +Okay so + + + align:start position:0% +Okay so +it's okay + + align:start position:0% + + + + align:start position:0% + +and oh by the way + + align:start position:0% +and oh by the way + + + align:start position:0% +and oh by the way +so so let me explain a little bit of of + + align:start position:0% +so so let me explain a little bit of of + + + align:start position:0% +so so let me explain a little bit of of +this notation this K does not mean the + + align:start position:0% +this notation this K does not mean the + + + align:start position:0% +this notation this K does not mean the +magnitude of K + + align:start position:0% +magnitude of K + + + align:start position:0% +magnitude of K +so this may okay + + align:start position:0% +so this may okay + + + align:start position:0% +so this may okay +k k means the uh because + + align:start position:0% +k k means the uh because + + + align:start position:0% +k k means the uh because +normally our convention is that the four + + align:start position:0% +normally our convention is that the four + + + align:start position:0% +normally our convention is that the four +vector + + align:start position:0% +vector + + + align:start position:0% +vector +says the X mu we always just write as X + + align:start position:0% +says the X mu we always just write as X + + + align:start position:0% +says the X mu we always just write as X +okay the P mu we just write as q p so + + align:start position:0% +okay the P mu we just write as q p so + + + align:start position:0% +okay the P mu we just write as q p so +here you should view this as a four + + align:start position:0% +here you should view this as a four + + + align:start position:0% +here you should view this as a four +Vector okay so it's a four Vector yeah + + align:start position:0% + + + + align:start position:0% + +it's just it's a shorthand notation + + align:start position:0% +it's just it's a shorthand notation + + + align:start position:0% +it's just it's a shorthand notation +so so K and K Bar + + align:start position:0% +so so K and K Bar + + + align:start position:0% +so so K and K Bar +then they have update charge okay + + align:start position:0% + + + + align:start position:0% + +have the same mass + + align:start position:0% + + + + align:start position:0% + +the same spin zero + + align:start position:0% + + + + align:start position:0% + +but of the charge + + align:start position:0% + + + + align:start position:0% + +so so by using this Q + + align:start position:0% +so so by using this Q + + + align:start position:0% +so so by using this Q +we cannot distinguish these two + + align:start position:0% +we cannot distinguish these two + + + align:start position:0% +we cannot distinguish these two +particles okay + + align:start position:0% + + + + align:start position:0% + +so so normally we call such a particle + + align:start position:0% +so so normally we call such a particle + + + align:start position:0% +so so normally we call such a particle +because in this case which they + + align:start position:0% +because in this case which they + + + align:start position:0% +because in this case which they +they are all quantum numbers are the + + align:start position:0% +they are all quantum numbers are the + + + align:start position:0% +they are all quantum numbers are the +same except some they have opposite + + align:start position:0% +same except some they have opposite + + + align:start position:0% +same except some they have opposite +charge we call them particle + + align:start position:0% +charge we call them particle + + + align:start position:0% +charge we call them particle +antiparticle okay so this would be + + align:start position:0% +antiparticle okay so this would be + + + align:start position:0% +antiparticle okay so this would be +called a creative particle + + align:start position:0% +called a creative particle + + + align:start position:0% +called a creative particle +so here we say they create anti-particle + + align:start position:0% + + + + align:start position:0% + +yes + + align:start position:0% + + + + align:start position:0% + +so um so here let me just make a a + + align:start position:0% +so um so here let me just make a a + + + align:start position:0% +so um so here let me just make a a +remark without proving it + + align:start position:0% +remark without proving it + + + align:start position:0% +remark without proving it +so so universities you can show + + align:start position:0% +so so universities you can show + + + align:start position:0% +so so universities you can show +that any particle + + align:start position:0% +that any particle + + + align:start position:0% +that any particle +has anti-particle okay in any Quantum + + align:start position:0% +has anti-particle okay in any Quantum + + + align:start position:0% +has anti-particle okay in any Quantum +field any relativity Quantum field + + align:start position:0% +field any relativity Quantum field + + + align:start position:0% +field any relativity Quantum field +Theory any particle has another particle + + align:start position:0% +Theory any particle has another particle + + + align:start position:0% +Theory any particle has another particle +okay + + align:start position:0% +okay + + + align:start position:0% +okay +in the case of the real scalar field + + align:start position:0% +in the case of the real scalar field + + + align:start position:0% +in the case of the real scalar field +you say we only have one particle in + + align:start position:0% +you say we only have one particle in + + + align:start position:0% +you say we only have one particle in +that case the under particle is itself + + align:start position:0% +that case the under particle is itself + + + align:start position:0% +that case the under particle is itself +okay and yeah + + align:start position:0% + + + + align:start position:0% + +good do you have any questions + + align:start position:0% +good do you have any questions + + + align:start position:0% +good do you have any questions +yes + + align:start position:0% + + + + align:start position:0% + +and served separately + + align:start position:0% +and served separately + + + align:start position:0% +and served separately +um having trouble seeing why + + align:start position:0% +um having trouble seeing why + + + align:start position:0% +um having trouble seeing why +conservation of Q is not trivial + + align:start position:0% +conservation of Q is not trivial + + + align:start position:0% +conservation of Q is not trivial +statement + + align:start position:0% +statement + + + align:start position:0% +statement +um + + align:start position:0% +um + + + align:start position:0% +um +yeah the conversation of Q for uh it + + align:start position:0% +yeah the conversation of Q for uh it + + + align:start position:0% +yeah the conversation of Q for uh it +follows from the symmetry + + align:start position:0% + + + + align:start position:0% + +like like the number of a particles + + align:start position:0% +like like the number of a particles + + + align:start position:0% +like like the number of a particles +number of B particles they're kind of + + align:start position:0% +number of B particles they're kind of + + + align:start position:0% +number of B particles they're kind of +separately considered so I just read off + + align:start position:0% +separately considered so I just read off + + + align:start position:0% +separately considered so I just read off +that Q is considered from the very + + align:start position:0% +that Q is considered from the very + + + align:start position:0% +that Q is considered from the very +beginning yeah it's a um + + align:start position:0% +beginning yeah it's a um + + + align:start position:0% +beginning yeah it's a um +no actually the uh the number of a + + align:start position:0% +no actually the uh the number of a + + + align:start position:0% +no actually the uh the number of a +particle and number B particle they're + + align:start position:0% +particle and number B particle they're + + + align:start position:0% +particle and number B particle they're +not a separately conserved they can + + align:start position:0% +not a separately conserved they can + + + align:start position:0% +not a separately conserved they can +actually in principle they can allow it + + align:start position:0% +actually in principle they can allow it + + + align:start position:0% +actually in principle they can allow it +yeah yeah here in freeze it with the + + align:start position:0% +yeah yeah here in freeze it with the + + + align:start position:0% +yeah yeah here in freeze it with the +canal they cannot align it but but if I + + align:start position:0% +canal they cannot align it but but if I + + + align:start position:0% +canal they cannot align it but but if I +can see the slightly more complicated + + align:start position:0% +can see the slightly more complicated + + + align:start position:0% +can see the slightly more complicated +series say if they're allowed to + + align:start position:0% +series say if they're allowed to + + + align:start position:0% +series say if they're allowed to +interact and then they can actually land + + align:start position:0% +interact and then they can actually land + + + align:start position:0% +interact and then they can actually land +it and then disappear and uh so in that + + align:start position:0% +it and then disappear and uh so in that + + + align:start position:0% +it and then disappear and uh so in that +case and but this formula still works + + align:start position:0% +case and but this formula still works + + + align:start position:0% +case and but this formula still works +this image is still there yeah so that's + + align:start position:0% +this image is still there yeah so that's + + + align:start position:0% +this image is still there yeah so that's +why the Symmetry is it's powerful also + + align:start position:0% +why the Symmetry is it's powerful also + + + align:start position:0% +why the Symmetry is it's powerful also +applies to to the case with interactions + + align:start position:0% +applies to to the case with interactions + + + align:start position:0% +applies to to the case with interactions +yeah yeah indeed what you what you said + + align:start position:0% +yeah yeah indeed what you what you said + + + align:start position:0% +yeah yeah indeed what you what you said +is correct uh in the in the free Theory + + align:start position:0% +is correct uh in the in the free Theory + + + align:start position:0% +is correct uh in the in the free Theory +yeah + + align:start position:0% +yeah + + + align:start position:0% +yeah +yes + + align:start position:0% + + + + align:start position:0% + +between serbs so they work in there + + align:start position:0% +between serbs so they work in there + + + align:start position:0% +between serbs so they work in there +yeah yeah essentially the property means + + align:start position:0% +yeah yeah essentially the property means + + + align:start position:0% +yeah yeah essentially the property means +they're probably almost identical except + + align:start position:0% +they're probably almost identical except + + + align:start position:0% +they're probably almost identical except +they have already charged + + align:start position:0% +they have already charged + + + align:start position:0% +they have already charged +yeah yeah they have essentially uh uh uh + + align:start position:0% +yeah yeah they have essentially uh uh uh + + + align:start position:0% +yeah yeah they have essentially uh uh uh +uh yeah just like real world we have + + align:start position:0% +uh yeah just like real world we have + + + align:start position:0% +uh yeah just like real world we have +electron we have anti if a matter we + + align:start position:0% +electron we have anti if a matter we + + + align:start position:0% +electron we have anti if a matter we +have antimatter uh uh they have a + + align:start position:0% +have antimatter uh uh they have a + + + align:start position:0% +have antimatter uh uh they have a +essential identical properties and if + + align:start position:0% +essential identical properties and if + + + align:start position:0% +essential identical properties and if +the world is made of anti-matter + + align:start position:0% +the world is made of anti-matter + + + align:start position:0% +the world is made of anti-matter +everything still will behave the same + + align:start position:0% +everything still will behave the same + + + align:start position:0% +everything still will behave the same +and yeah yeah but the except just the + + align:start position:0% +and yeah yeah but the except just the + + + align:start position:0% +and yeah yeah but the except just the +charge is different + + align:start position:0% +charge is different + + + align:start position:0% +charge is different +between the number of anti-particles and + + align:start position:0% +between the number of anti-particles and + + + align:start position:0% +between the number of anti-particles and +particles + + align:start position:0% +particles + + + align:start position:0% +particles +is conserved yeah it's conserved yeah + + align:start position:0% + + + + align:start position:0% + +right so + + align:start position:0% +right so + + + align:start position:0% +right so +um I guess this is like the electric + + align:start position:0% +um I guess this is like the electric + + + align:start position:0% +um I guess this is like the electric +charge or or is this some other charge I + + align:start position:0% +charge or or is this some other charge I + + + align:start position:0% +charge or or is this some other charge I +think some other charge + + align:start position:0% +think some other charge + + + align:start position:0% +think some other charge +so so in the case uh we will go to when + + align:start position:0% +so so in the case uh we will go to when + + + align:start position:0% +so so in the case uh we will go to when +we talk about electrons so you know the + + align:start position:0% +we talk about electrons so you know the + + + align:start position:0% +we talk about electrons so you know the +electrons involving more complications + + align:start position:0% +electrons involving more complications + + + align:start position:0% +electrons involving more complications +we have to introduce spin particle with + + align:start position:0% +we have to introduce spin particle with + + + align:start position:0% +we have to introduce spin particle with +spin in that case we also have an + + align:start position:0% +spin in that case we also have an + + + align:start position:0% +spin in that case we also have an +electron anti-election and in that case + + align:start position:0% +electron anti-election and in that case + + + align:start position:0% +electron anti-election and in that case +it's a story is parallel and uh yeah + + align:start position:0% +it's a story is parallel and uh yeah + + + align:start position:0% +it's a story is parallel and uh yeah +so this does not necessarily involve + + align:start position:0% +so this does not necessarily involve + + + align:start position:0% +so this does not necessarily involve +yeah or like yes repellent no no no yeah + + align:start position:0% +yeah or like yes repellent no no no yeah + + + align:start position:0% +yeah or like yes repellent no no no yeah +but but this is the analog of that is + + align:start position:0% +but but this is the analog of that is + + + align:start position:0% +but but this is the analog of that is +analog of that so the charge here uh + + align:start position:0% +analog of that so the charge here uh + + + align:start position:0% +analog of that so the charge here uh +they can be some other kind of charge + + align:start position:0% +they can be some other kind of charge + + + align:start position:0% +they can be some other kind of charge +does not have to be uh yeah yeah + + align:start position:0% + + + + align:start position:0% + +how can you get like something that's + + align:start position:0% +how can you get like something that's + + + align:start position:0% +how can you get like something that's +physical that's conserved from a + + align:start position:0% +physical that's conserved from a + + + align:start position:0% +physical that's conserved from a +symmetry that's not really physical like + + align:start position:0% +symmetry that's not really physical like + + + align:start position:0% +symmetry that's not really physical like +this is not like you can translate in + + align:start position:0% +this is not like you can translate in + + + align:start position:0% +this is not like you can translate in +space or like translating time this is I + + align:start position:0% +space or like translating time this is I + + + align:start position:0% +space or like translating time this is I +don't understand I don't know how to + + align:start position:0% +don't understand I don't know how to + + + align:start position:0% +don't understand I don't know how to +think about it yeah yeah that's why we + + align:start position:0% +think about it yeah yeah that's why we + + + align:start position:0% +think about it yeah yeah that's why we +call + + align:start position:0% + + + + align:start position:0% + +so for since we don't have good + + align:start position:0% +so for since we don't have good + + + align:start position:0% +so for since we don't have good +intuition about + + align:start position:0% +intuition about + + + align:start position:0% +intuition about +you just invent the new name for it + + align:start position:0% +you just invent the new name for it + + + align:start position:0% +you just invent the new name for it +and and once you get used to this new + + align:start position:0% +and and once you get used to this new + + + align:start position:0% +and and once you get used to this new +name you say oh I understand it + + align:start position:0% +name you say oh I understand it + + + align:start position:0% +name you say oh I understand it +yeah yeah it it is more or less to + + align:start position:0% +yeah yeah it it is more or less to + + + align:start position:0% +yeah yeah it it is more or less to +getting used to it and indeed at first + + align:start position:0% +getting used to it and indeed at first + + + align:start position:0% +getting used to it and indeed at first +side it's not very intuitive because + + align:start position:0% +side it's not very intuitive because + + + align:start position:0% +side it's not very intuitive because +it's not something you can + + align:start position:0% +it's not something you can + + + align:start position:0% +it's not something you can +yeah from your normal experiences Etc + + align:start position:0% +yeah from your normal experiences Etc + + + align:start position:0% +yeah from your normal experiences Etc +but uh yeah but this is the uh + + align:start position:0% +but uh yeah but this is the uh + + + align:start position:0% +but uh yeah but this is the uh +yeah but this is us + + align:start position:0% +yeah but this is us + + + align:start position:0% +yeah but this is us +as fundamental level is not that + + align:start position:0% +as fundamental level is not that + + + align:start position:0% +as fundamental level is not that +different from energy conservation it's + + align:start position:0% +different from energy conservation it's + + + align:start position:0% +different from energy conservation it's +just some symmetry and then this to some + + align:start position:0% +just some symmetry and then this to some + + + align:start position:0% +just some symmetry and then this to some +conserved quantities + + align:start position:0% + + + + align:start position:0% + +yes + + align:start position:0% + + + + align:start position:0% + +electric charge and like which ones do + + align:start position:0% +electric charge and like which ones do + + + align:start position:0% +electric charge and like which ones do +we call I guess particulines + + align:start position:0% +we call I guess particulines + + + align:start position:0% +we call I guess particulines +does that make sense yeah yeah that's + + align:start position:0% +does that make sense yeah yeah that's + + + align:start position:0% +does that make sense yeah yeah that's +right they can hide they can in + + align:start position:0% +right they can hide they can in + + + align:start position:0% +right they can hide they can in +principle have multiple charges but the + + align:start position:0% +principle have multiple charges but the + + + align:start position:0% +principle have multiple charges but the +particle and the particle they're always + + align:start position:0% +particle and the particle they're always + + + align:start position:0% +particle and the particle they're always +opposite + + align:start position:0% +opposite + + + align:start position:0% +opposite +yeah yeah in terms of charges they're + + align:start position:0% +yeah yeah in terms of charges they're + + + align:start position:0% +yeah yeah in terms of charges they're +always opposite yeah whatever charges + + align:start position:0% +always opposite yeah whatever charges + + + align:start position:0% +always opposite yeah whatever charges +you have + + align:start position:0% +you have + + + align:start position:0% +you have +two different charges that each one can + + align:start position:0% +two different charges that each one can + + + align:start position:0% +two different charges that each one can +have you know instead of four things is + + align:start position:0% +have you know instead of four things is + + + align:start position:0% +have you know instead of four things is +it a different language yeah yeah I + + align:start position:0% +it a different language yeah yeah I + + + align:start position:0% +it a different language yeah yeah I +think yeah uh um + + align:start position:0% + + + + align:start position:0% + +yeah you can have them but but for + + align:start position:0% +yeah you can have them but but for + + + align:start position:0% +yeah you can have them but but for +particle and particle they're always + + align:start position:0% +particle and particle they're always + + + align:start position:0% +particle and particle they're always +opposite + + align:start position:0% +opposite + + + align:start position:0% +opposite +yeah they can have multiple charges but + + align:start position:0% +yeah they can have multiple charges but + + + align:start position:0% +yeah they can have multiple charges but +they're always opposite + + align:start position:0% + + + + align:start position:0% + +other questions + + align:start position:0% + + + + align:start position:0% + +okay good good + + align:start position:0% +okay good good + + + align:start position:0% +okay good good +so so this concludes our discussion + + align:start position:0% +so so this concludes our discussion + + + align:start position:0% +so so this concludes our discussion +of the complex + + align:start position:0% +of the complex + + + align:start position:0% +of the complex +field + + align:start position:0% + + + + align:start position:0% + +um + + align:start position:0% +um + + + align:start position:0% +um +so we have a few minutes + + align:start position:0% +so we have a few minutes + + + align:start position:0% +so we have a few minutes +then it's to uh to the next + + align:start position:0% +then it's to uh to the next + + + align:start position:0% +then it's to uh to the next +topic + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% + + + + align:start position:0% + +hopefully + + align:start position:0% + + + + align:start position:0% + +so now let's talk about the + + align:start position:0% +so now let's talk about the + + + align:start position:0% +so now let's talk about the +concept called the propagators + + align:start position:0% +concept called the propagators + + + align:start position:0% +concept called the propagators +so so in so again let's recall in our + + align:start position:0% +so so in so again let's recall in our + + + align:start position:0% +so so in so again let's recall in our +activity quantum mechanics + + align:start position:0% + + + + align:start position:0% + +so this position Vector plays a hero + + align:start position:0% +so this position Vector plays a hero + + + align:start position:0% +so this position Vector plays a hero +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so this is the eigenvector + + align:start position:0% + + + + align:start position:0% + +of this + + align:start position:0% +of this + + + align:start position:0% +of this +X which is the position operator + + align:start position:0% +X which is the position operator + + + align:start position:0% +X which is the position operator +okay so again I will uh yeah let me just + + align:start position:0% +okay so again I will uh yeah let me just + + + align:start position:0% +okay so again I will uh yeah let me just +put a hat here to emphasize this is the + + align:start position:0% +put a hat here to emphasize this is the + + + align:start position:0% +put a hat here to emphasize this is the +operator + + align:start position:0% +operator + + + align:start position:0% +operator +and so so this is the eigenved of X okay + + align:start position:0% +and so so this is the eigenved of X okay + + + align:start position:0% +and so so this is the eigenved of X okay +and because this player key role because + + align:start position:0% +and because this player key role because + + + align:start position:0% +and because this player key role because +we need to use this to define the wave + + align:start position:0% +we need to use this to define the wave + + + align:start position:0% +we need to use this to define the wave +functions + + align:start position:0% + + + + align:start position:0% + +and then the uh the amplitude of the + + align:start position:0% +and then the uh the amplitude of the + + + align:start position:0% +and then the uh the amplitude of the +wave function the square + + align:start position:0% +wave function the square + + + align:start position:0% +wave function the square +give us the probability of a particle at + + align:start position:0% +give us the probability of a particle at + + + align:start position:0% +give us the probability of a particle at +location X okay so so this is a crucial + + align:start position:0% +location X okay so so this is a crucial + + + align:start position:0% +location X okay so so this is a crucial +uh quantity + + align:start position:0% +uh quantity + + + align:start position:0% +uh quantity +so so this language + + align:start position:0% +so so this language + + + align:start position:0% +so so this language +uh normally we talk about the uh the + + align:start position:0% +uh normally we talk about the uh the + + + align:start position:0% +uh normally we talk about the uh the +shorting a picture you started with + + align:start position:0% +shorting a picture you started with + + + align:start position:0% +shorting a picture you started with +percent X + + align:start position:0% + + + + align:start position:0% + +at t equal to zero + + align:start position:0% +at t equal to zero + + + align:start position:0% +at t equal to zero +and then you try to find + + align:start position:0% +and then you try to find + + + align:start position:0% +and then you try to find +yeah or yeah let me say + + align:start position:0% +yeah or yeah let me say + + + align:start position:0% +yeah or yeah let me say +you start to set X + + align:start position:0% + + + + align:start position:0% + +say t Prime I sum T Prime + + align:start position:0% + + + + align:start position:0% + +okay you want to find PSI + + align:start position:0% +okay you want to find PSI + + + align:start position:0% +okay you want to find PSI +X at some t Okay so so this is the + + align:start position:0% +X at some t Okay so so this is the + + + align:start position:0% +X at some t Okay so so this is the +depression of quantum mechanics okay + + align:start position:0% +depression of quantum mechanics okay + + + align:start position:0% +depression of quantum mechanics okay +so if you know the wave function at the + + align:start position:0% +so if you know the wave function at the + + + align:start position:0% +so if you know the wave function at the +initial time and you want to find the + + align:start position:0% +initial time and you want to find the + + + align:start position:0% +initial time and you want to find the +the wave functions on future time + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +so now let's imagine we consider this + + align:start position:0% +so now let's imagine we consider this + + + align:start position:0% +so now let's imagine we consider this +question Heisenberg picture + + align:start position:0% + + + + align:start position:0% + +so he showed him a picture there's just + + align:start position:0% +so he showed him a picture there's just + + + align:start position:0% +so he showed him a picture there's just +one + + align:start position:0% +one + + + align:start position:0% +one +okay they just the one eigenvector + + align:start position:0% +okay they just the one eigenvector + + + align:start position:0% +okay they just the one eigenvector +uh yeah just one set of eigenvectors for + + align:start position:0% +uh yeah just one set of eigenvectors for + + + align:start position:0% +uh yeah just one set of eigenvectors for +X okay for different eigenvalues + + align:start position:0% +X okay for different eigenvalues + + + align:start position:0% +X okay for different eigenvalues +but for for the Heisenberg picture now + + align:start position:0% + + + + align:start position:0% + +your position operator now depend on + + align:start position:0% +your position operator now depend on + + + align:start position:0% +your position operator now depend on +time + + align:start position:0% +time + + + align:start position:0% +time +okay so the position operates at + + align:start position:0% +okay so the position operates at + + + align:start position:0% +okay so the position operates at +different times they are different + + align:start position:0% +different times they are different + + + align:start position:0% +different times they are different +so now if you want to talk about the + + align:start position:0% +so now if you want to talk about the + + + align:start position:0% +so now if you want to talk about the +position eigenvector now you read the + + align:start position:0% +position eigenvector now you read the + + + align:start position:0% +position eigenvector now you read the +label + + align:start position:0% +label + + + align:start position:0% +label +okay so now the position eigenvector + + align:start position:0% + + + + align:start position:0% + +is the T label okay + + align:start position:0% +is the T label okay + + + align:start position:0% +is the T label okay +this T does not mean that this exactly + + align:start position:0% +this T does not mean that this exactly + + + align:start position:0% +this T does not mean that this exactly +evolved with time it just this is the + + align:start position:0% +evolved with time it just this is the + + + align:start position:0% +evolved with time it just this is the +label okay this means that this is the + + align:start position:0% +label okay this means that this is the + + + align:start position:0% +label okay this means that this is the +eigenvector of + + align:start position:0% + + + + align:start position:0% + +position Vector at time t + + align:start position:0% + + + + align:start position:0% + +okay this just tells you this is the egg + + align:start position:0% +okay this just tells you this is the egg + + + align:start position:0% +okay this just tells you this is the egg +marked at time T okay + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and now the question of this question of + + align:start position:0% +and now the question of this question of + + + align:start position:0% +and now the question of this question of +this the question of quantum mechanics + + align:start position:0% +this the question of quantum mechanics + + + align:start position:0% +this the question of quantum mechanics +then can be reformulated into a + + align:start position:0% +then can be reformulated into a + + + align:start position:0% +then can be reformulated into a +different question + + align:start position:0% +different question + + + align:start position:0% +different question +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so so in this story the question of + + align:start position:0% +so so in this story the question of + + + align:start position:0% +so so in this story the question of +quantum mechanics + + align:start position:0% + + + + align:start position:0% + +becomes the following + + align:start position:0% +becomes the following + + + align:start position:0% +becomes the following +what is the value + + align:start position:0% + + + + align:start position:0% + +of this object + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +suppose + + align:start position:0% +suppose + + + align:start position:0% +suppose +you are in the eigen state + + align:start position:0% +you are in the eigen state + + + align:start position:0% +you are in the eigen state +you are you are analog you are the econ + + align:start position:0% +you are you are analog you are the econ + + + align:start position:0% +you are you are analog you are the econ +Vector you are in the position + + align:start position:0% +Vector you are in the position + + + align:start position:0% +Vector you are in the position +eigenvector you are in the position + + align:start position:0% +eigenvector you are in the position + + + align:start position:0% +eigenvector you are in the position +eigenstate + + align:start position:0% +eigenstate + + + align:start position:0% +eigenstate +uh at time T Prime with value X Prime + + align:start position:0% +uh at time T Prime with value X Prime + + + align:start position:0% +uh at time T Prime with value X Prime +and what's the amplitude for you to go + + align:start position:0% +and what's the amplitude for you to go + + + align:start position:0% +and what's the amplitude for you to go +to location X at time T okay + + align:start position:0% +to location X at time T okay + + + align:start position:0% +to location X at time T okay +okay remember this this does not involve + + align:start position:0% +okay remember this this does not involve + + + align:start position:0% +okay remember this this does not involve +time Evolution this just because one is + + align:start position:0% +time Evolution this just because one is + + + align:start position:0% +time Evolution this just because one is +labeling different uh economics at + + align:start position:0% +labeling different uh economics at + + + align:start position:0% +labeling different uh economics at +different time okay + + align:start position:0% +different time okay + + + align:start position:0% +different time okay +so if you know this object this is + + align:start position:0% +so if you know this object this is + + + align:start position:0% +so if you know this object this is +called this will be normally below the G + + align:start position:0% + + + + align:start position:0% + +you know gee this is called the + + align:start position:0% +you know gee this is called the + + + align:start position:0% +you know gee this is called the +propagator + + align:start position:0% + + + + align:start position:0% + +okay this is called the propagator + + align:start position:0% +okay this is called the propagator + + + align:start position:0% +okay this is called the propagator +so if you know the propagator + + align:start position:0% + + + + align:start position:0% + +of a Quantum system + + align:start position:0% +of a Quantum system + + + align:start position:0% +of a Quantum system +then you have full rollage of that + + align:start position:0% +then you have full rollage of that + + + align:start position:0% +then you have full rollage of that +system so you have to solve the system + + align:start position:0% +system so you have to solve the system + + + align:start position:0% +system so you have to solve the system +why + + align:start position:0% +why + + + align:start position:0% +why +because say let's imagine we want to + + align:start position:0% +because say let's imagine we want to + + + align:start position:0% +because say let's imagine we want to +find PSI TX + + align:start position:0% +find PSI TX + + + align:start position:0% +find PSI TX +wave function at time t + + align:start position:0% +wave function at time t + + + align:start position:0% +wave function at time t +and then by definition + + align:start position:0% +and then by definition + + + align:start position:0% +and then by definition +this is given by this so this is the + + align:start position:0% +this is given by this so this is the + + + align:start position:0% +this is given by this so this is the +Heisenberg picture of a definition okay + + align:start position:0% +Heisenberg picture of a definition okay + + + align:start position:0% +Heisenberg picture of a definition okay +it's the side the overlap with the + + align:start position:0% +it's the side the overlap with the + + + align:start position:0% +it's the side the overlap with the +position Vector at time t + + align:start position:0% + + + + align:start position:0% + +and now this is now we can insert the + + align:start position:0% +and now this is now we can insert the + + + align:start position:0% +and now this is now we can insert the +complete set of State + + align:start position:0% + + + + align:start position:0% + +okay I just insert the complete side + + align:start position:0% +okay I just insert the complete side + + + align:start position:0% +okay I just insert the complete side +here just this is identity okay + + align:start position:0% +here just this is identity okay + + + align:start position:0% +here just this is identity okay +and then underneath the object is just G + + align:start position:0% + + + + align:start position:0% + +so you just get G + + align:start position:0% +so you just get G + + + align:start position:0% +so you just get G +x t + + align:start position:0% +x t + + + align:start position:0% +x t +X Prime P Prime then PSI T Prime X Prime + + align:start position:0% +X Prime P Prime then PSI T Prime X Prime + + + align:start position:0% +X Prime P Prime then PSI T Prime X Prime +okay + + align:start position:0% + + + + align:start position:0% + +so if you know + + align:start position:0% +so if you know + + + align:start position:0% +so if you know +so yeah so so this just gave you the + + align:start position:0% +so yeah so so this just gave you the + + + align:start position:0% +so yeah so so this just gave you the +wave function at T Prime + + align:start position:0% +wave function at T Prime + + + align:start position:0% +wave function at T Prime +so now if you load this + + align:start position:0% +so now if you load this + + + align:start position:0% +so now if you load this +you're given the initial wave function + + align:start position:0% +you're given the initial wave function + + + align:start position:0% +you're given the initial wave function +if you know the propagator + + align:start position:0% +if you know the propagator + + + align:start position:0% +if you know the propagator +you just need to do an integral okay + + align:start position:0% +you just need to do an integral okay + + + align:start position:0% +you just need to do an integral okay +then you find the wave function here + + align:start position:0% +then you find the wave function here + + + align:start position:0% +then you find the wave function here +so the full range of your quantum + + align:start position:0% +so the full range of your quantum + + + align:start position:0% +so the full range of your quantum +mechanical system essentially is encoded + + align:start position:0% +mechanical system essentially is encoded + + + align:start position:0% +mechanical system essentially is encoded +in this propagator + + align:start position:0% +in this propagator + + + align:start position:0% +in this propagator +okay + + align:start position:0% +okay + + + align:start position:0% +okay +is encoded in this propagator + + align:start position:0% +is encoded in this propagator + + + align:start position:0% +is encoded in this propagator +so um yeah so so now we want to talk + + align:start position:0% +so um yeah so so now we want to talk + + + align:start position:0% +so um yeah so so now we want to talk +about what is the analog of this object + + align:start position:0% +about what is the analog of this object + + + align:start position:0% +about what is the analog of this object +say and you write a b c Quantum field + + align:start position:0% +say and you write a b c Quantum field + + + align:start position:0% +say and you write a b c Quantum field +okay uh in Quantum field how do we + + align:start position:0% +okay uh in Quantum field how do we + + + align:start position:0% +okay uh in Quantum field how do we +Define a propagator and what is the + + align:start position:0% +Define a propagator and what is the + + + align:start position:0% +Define a propagator and what is the +what is the analog of the position eigen + + align:start position:0% +what is the analog of the position eigen + + + align:start position:0% +what is the analog of the position eigen +State say in Quantum field Theory okay + + align:start position:0% +State say in Quantum field Theory okay + + + align:start position:0% +State say in Quantum field Theory okay +and we will discuss next time \ No newline at end of file diff --git a/wezQdmwolMU.txt b/wezQdmwolMU.txt new file mode 100644 index 0000000000000000000000000000000000000000..ff3926019c5659448e697852fc6f6980c4b1dd51 --- /dev/null +++ b/wezQdmwolMU.txt @@ -0,0 +1,1355 @@ +align:start position:0% + +Welcome back to recitation. Uh we're + + align:start position:0% +Welcome back to recitation. Uh we're + + + align:start position:0% +Welcome back to recitation. Uh we're +going to practice using some of the some + + align:start position:0% +going to practice using some of the some + + + align:start position:0% +going to practice using some of the some +of the tools you developed recently on + + align:start position:0% +of the tools you developed recently on + + + align:start position:0% +of the tools you developed recently on +taking derivatives of exponential + + align:start position:0% +taking derivatives of exponential + + + align:start position:0% +taking derivatives of exponential +functions and taking derivatives of + + align:start position:0% +functions and taking derivatives of + + + align:start position:0% +functions and taking derivatives of +logarithmic functions. So I have three + + align:start position:0% +logarithmic functions. So I have three + + + align:start position:0% +logarithmic functions. So I have three +uh particular examples that I want us to + + align:start position:0% +uh particular examples that I want us to + + + align:start position:0% +uh particular examples that I want us to +look at and I'd like us to find + + align:start position:0% +look at and I'd like us to find + + + align:start position:0% +look at and I'd like us to find +derivatives of the following functions. + + align:start position:0% +derivatives of the following functions. + + + align:start position:0% +derivatives of the following functions. +The first one is f ofx is equal to x pi + + align:start position:0% +The first one is f ofx is equal to x pi + + + align:start position:0% +The first one is f ofx is equal to x pi +plus p to x. The second function is g + + align:start position:0% +plus p to x. The second function is g + + + align:start position:0% +plus p to x. The second function is g +ofx is equal to natural log of cosine of + + align:start position:0% +ofx is equal to natural log of cosine of + + + align:start position:0% +ofx is equal to natural log of cosine of +x. And the third one is that's an h, not + + align:start position:0% +x. And the third one is that's an h, not + + + align:start position:0% +x. And the third one is that's an h, not +a natural log. h ofx is equal to natural + + align:start position:0% +a natural log. h ofx is equal to natural + + + align:start position:0% +a natural log. h ofx is equal to natural +log of e to x^2. So you have three + + align:start position:0% +log of e to x^2. So you have three + + + align:start position:0% +log of e to x^2. So you have three +functions you want to take the + + align:start position:0% +functions you want to take the + + + align:start position:0% +functions you want to take the +derivative of with respect to x. I'm + + align:start position:0% +derivative of with respect to x. I'm + + + align:start position:0% +derivative of with respect to x. I'm +going to give you a moment to uh to work + + align:start position:0% +going to give you a moment to uh to work + + + align:start position:0% +going to give you a moment to uh to work +on those and figure those out using the + + align:start position:0% +on those and figure those out using the + + + align:start position:0% +on those and figure those out using the +the tools you now have. And then we'll + + align:start position:0% +the tools you now have. And then we'll + + + align:start position:0% +the tools you now have. And then we'll +come back and I will work them out for + + align:start position:0% +come back and I will work them out for + + + align:start position:0% +come back and I will work them out for +you as well. + + align:start position:0% + + + + align:start position:0% + +Okay, so let's start off with the + + align:start position:0% +Okay, so let's start off with the + + + align:start position:0% +Okay, so let's start off with the +derivative of the first one. Okay, now + + align:start position:0% +derivative of the first one. Okay, now + + + align:start position:0% +derivative of the first one. Okay, now +the reason in particular that I that I + + align:start position:0% +the reason in particular that I that I + + + align:start position:0% +the reason in particular that I that I +did this one might have seemed simple to + + align:start position:0% +did this one might have seemed simple to + + + align:start position:0% +did this one might have seemed simple to +you, but the reason I did this one is + + align:start position:0% +you, but the reason I did this one is + + + align:start position:0% +you, but the reason I did this one is +because of a common mistake that people + + align:start position:0% +because of a common mistake that people + + + align:start position:0% +because of a common mistake that people +make. Okay, so the derivative of x to + + align:start position:0% +make. Okay, so the derivative of x to + + + align:start position:0% +make. Okay, so the derivative of x to +the pi is uh is nice and simple because + + align:start position:0% +the pi is uh is nice and simple because + + + align:start position:0% +the pi is uh is nice and simple because +that is our uh rule we know for uh + + align:start position:0% +that is our uh rule we know for uh + + + align:start position:0% +that is our uh rule we know for uh +powers of x. So we can write this as + + align:start position:0% +powers of x. So we can write this as + + + align:start position:0% +powers of x. So we can write this as +that derivative is pi * x^ minus one. + + align:start position:0% +that derivative is pi * x^ minus one. + + + align:start position:0% +that derivative is pi * x^ minus one. +Okay. But the whole point of this + + align:start position:0% +Okay. But the whole point of this + + + align:start position:0% +Okay. But the whole point of this +problem for me is to make sure that you + + align:start position:0% +problem for me is to make sure that you + + + align:start position:0% +problem for me is to make sure that you +recognize that pi to the x is not a + + align:start position:0% +recognize that pi to the x is not a + + + align:start position:0% +recognize that pi to the x is not a +power of of x rule that needs to be + + align:start position:0% +power of of x rule that needs to be + + + align:start position:0% +power of of x rule that needs to be +applied. It's actually an exponential + + align:start position:0% +applied. It's actually an exponential + + + align:start position:0% +applied. It's actually an exponential +function, right? With base pi. So if you + + align:start position:0% +function, right? With base pi. So if you + + + align:start position:0% +function, right? With base pi. So if you +wrote uh the derivative of this term was + + align:start position:0% +wrote uh the derivative of this term was + + + align:start position:0% +wrote uh the derivative of this term was +x sorry was x * pi to the xus one, you + + align:start position:0% +x sorry was x * pi to the xus one, you + + + align:start position:0% +x sorry was x * pi to the xus one, you +would not be alone in the world. But + + align:start position:0% +would not be alone in the world. But + + + align:start position:0% +would not be alone in the world. But +that is not the correct answer all the + + align:start position:0% +that is not the correct answer all the + + + align:start position:0% +that is not the correct answer all the +same because this is not a a power of x. + + align:start position:0% +same because this is not a a power of x. + + + align:start position:0% +same because this is not a a power of x. +This is x is the power. So this is an + + align:start position:0% +This is x is the power. So this is an + + + align:start position:0% +This is x is the power. So this is an +exponential function. So the derivative + + align:start position:0% +exponential function. So the derivative + + + align:start position:0% +exponential function. So the derivative +of this we need the rule that we have + + align:start position:0% +of this we need the rule that we have + + + align:start position:0% +of this we need the rule that we have +for exponential uh derivatives of + + align:start position:0% +for exponential uh derivatives of + + + align:start position:0% +for exponential uh derivatives of +exponential functions. So that's natural + + align:start position:0% +exponential functions. So that's natural + + + align:start position:0% +exponential functions. So that's natural +log of pi + + align:start position:0% +log of pi + + + align:start position:0% +log of pi +time pi to the x. That's the derivative + + align:start position:0% +time pi to the x. That's the derivative + + + align:start position:0% +time pi to the x. That's the derivative +of pi to the x. Um so that's the answer + + align:start position:0% +of pi to the x. Um so that's the answer + + + align:start position:0% +of pi to the x. Um so that's the answer +to number one. Okay. Number two I did + + align:start position:0% +to number one. Okay. Number two I did + + + align:start position:0% +to number one. Okay. Number two I did +for another reason. I think it's a It's + + align:start position:0% +for another reason. I think it's a It's + + + align:start position:0% +for another reason. I think it's a It's +an interesting function um once you find + + align:start position:0% +an interesting function um once you find + + + align:start position:0% +an interesting function um once you find +out what the derivative is. So this is + + align:start position:0% +out what the derivative is. So this is + + + align:start position:0% +out what the derivative is. So this is +going to require us to do the chain rule + + align:start position:0% +going to require us to do the chain rule + + + align:start position:0% +going to require us to do the chain rule +because we have a function of a + + align:start position:0% +because we have a function of a + + + align:start position:0% +because we have a function of a +function. Um but you have seen many + + align:start position:0% +function. Um but you have seen many + + + align:start position:0% +function. Um but you have seen many +times now when you have natural log of a + + align:start position:0% +times now when you have natural log of a + + + align:start position:0% +times now when you have natural log of a +function its derivative + + align:start position:0% +function its derivative + + + align:start position:0% +function its derivative +uh is going to be one over one over the + + align:start position:0% +uh is going to be one over one over the + + + align:start position:0% +uh is going to be one over one over the +inside function times then the + + align:start position:0% +inside function times then the + + + align:start position:0% +inside function times then the +derivative of the inside function. So + + align:start position:0% +derivative of the inside function. So + + + align:start position:0% +derivative of the inside function. So +again what we do is we take the + + align:start position:0% +again what we do is we take the + + + align:start position:0% +again what we do is we take the +derivative of natural log which is 1 + + align:start position:0% +derivative of natural log which is 1 + + + align:start position:0% +derivative of natural log which is 1 +over + + align:start position:0% +over + + + align:start position:0% +over +cossine x. So we take the derivative of + + align:start position:0% +cossine x. So we take the derivative of + + + align:start position:0% +cossine x. So we take the derivative of +the natural log function evaluate it at + + align:start position:0% +the natural log function evaluate it at + + + align:start position:0% +the natural log function evaluate it at +cosine x and then we take the derivative + + align:start position:0% +cosine x and then we take the derivative + + + align:start position:0% +cosine x and then we take the derivative +of the inside function which is the + + align:start position:0% +of the inside function which is the + + + align:start position:0% +of the inside function which is the +derivative of cosine x. So you get + + align:start position:0% +derivative of cosine x. So you get + + + align:start position:0% +derivative of cosine x. So you get +negative sinx. + + align:start position:0% +negative sinx. + + + align:start position:0% +negative sinx. +So you get this whole thing is negative + + align:start position:0% +So you get this whole thing is negative + + + align:start position:0% +So you get this whole thing is negative +of s over cosine. So this is negative + + align:start position:0% +of s over cosine. So this is negative + + + align:start position:0% +of s over cosine. So this is negative +tangent x. + + align:start position:0% +tangent x. + + + align:start position:0% +tangent x. +So the reason I in particular like this + + align:start position:0% +So the reason I in particular like this + + + align:start position:0% +So the reason I in particular like this +one is that we see oh if I wanted to + + align:start position:0% +one is that we see oh if I wanted to + + + align:start position:0% +one is that we see oh if I wanted to +find a function whose derivative was + + align:start position:0% +find a function whose derivative was + + + align:start position:0% +find a function whose derivative was +tangent x a candidate would be the + + align:start position:0% +tangent x a candidate would be the + + + align:start position:0% +tangent x a candidate would be the +negative of the natural log of cosine of + + align:start position:0% +negative of the natural log of cosine of + + + align:start position:0% +negative of the natural log of cosine of +x that in fact gives us a function whose + + align:start position:0% +x that in fact gives us a function whose + + + align:start position:0% +x that in fact gives us a function whose +derivative is tangent x. So it's + + align:start position:0% +derivative is tangent x. So it's + + + align:start position:0% +derivative is tangent x. So it's +interesting now we see that there are uh + + align:start position:0% +interesting now we see that there are uh + + + align:start position:0% +interesting now we see that there are uh +trigonometric functions that I can take + + align:start position:0% +trigonometric functions that I can take + + + align:start position:0% +trigonometric functions that I can take +a derivative of something that's not + + align:start position:0% +a derivative of something that's not + + + align:start position:0% +a derivative of something that's not +just trigonometric and get something + + align:start position:0% +just trigonometric and get something + + + align:start position:0% +just trigonometric and get something +that's trigonometric. So that's kind of + + align:start position:0% +that's trigonometric. So that's kind of + + + align:start position:0% +that's trigonometric. So that's kind of +a nice thing there. And then the last + + align:start position:0% +a nice thing there. And then the last + + + align:start position:0% +a nice thing there. And then the last +one, example three, I'll work out to the + + align:start position:0% +one, example three, I'll work out to the + + + align:start position:0% +one, example three, I'll work out to the +right. Uh there is a fast way and there + + align:start position:0% +right. Uh there is a fast way and there + + + align:start position:0% +right. Uh there is a fast way and there +is a slow way to do this. So I will do + + align:start position:0% +is a slow way to do this. So I will do + + + align:start position:0% +is a slow way to do this. So I will do +the slow way first and then I'll show + + align:start position:0% +the slow way first and then I'll show + + + align:start position:0% +the slow way first and then I'll show +you why it's good to kind of pull back + + align:start position:0% +you why it's good to kind of pull back + + + align:start position:0% +you why it's good to kind of pull back +from a problem sometimes. See how you + + align:start position:0% +from a problem sometimes. See how you + + + align:start position:0% +from a problem sometimes. See how you +can make it a lot simpler for yourself + + align:start position:0% +can make it a lot simpler for yourself + + + align:start position:0% +can make it a lot simpler for yourself +and then and then solve the problem. So + + align:start position:0% +and then and then solve the problem. So + + + align:start position:0% +and then and then solve the problem. So +I'll even write down this is the slow + + align:start position:0% +I'll even write down this is the slow + + + align:start position:0% +I'll even write down this is the slow +way. + + align:start position:0% + + + + align:start position:0% + +Okay, the slow way would be well I have + + align:start position:0% +Okay, the slow way would be well I have + + + align:start position:0% +Okay, the slow way would be well I have +um I have an a composition of functions + + align:start position:0% +um I have an a composition of functions + + + align:start position:0% +um I have an a composition of functions +here. I have natural log of something + + align:start position:0% +here. I have natural log of something + + + align:start position:0% +here. I have natural log of something +and then I have e to the something else, + + align:start position:0% +and then I have e to the something else, + + + align:start position:0% +and then I have e to the something else, +right? And then that function actually + + align:start position:0% +right? And then that function actually + + + align:start position:0% +right? And then that function actually +is not just e to the x. So I have some + + align:start position:0% +is not just e to the x. So I have some + + + align:start position:0% +is not just e to the x. So I have some +some things I have to I have to use the + + align:start position:0% +some things I have to I have to use the + + + align:start position:0% +some things I have to I have to use the +chain rule here. Okay, so let's use the + + align:start position:0% +chain rule here. Okay, so let's use the + + + align:start position:0% +chain rule here. Okay, so let's use the +chain rule. So I'll work from the + + align:start position:0% +chain rule. So I'll work from the + + + align:start position:0% +chain rule. So I'll work from the +outside in. So the derivative of the + + align:start position:0% +outside in. So the derivative of the + + + align:start position:0% +outside in. So the derivative of the +natural log function the derivative of + + align:start position:0% +natural log function the derivative of + + + align:start position:0% +natural log function the derivative of +natural log of x is 1 /x. So I take the + + align:start position:0% +natural log of x is 1 /x. So I take the + + + align:start position:0% +natural log of x is 1 /x. So I take the +derivative of natural log function. I + + align:start position:0% +derivative of natural log function. I + + + align:start position:0% +derivative of natural log function. I +evaluate it here. So the first part + + align:start position:0% +evaluate it here. So the first part + + + align:start position:0% +evaluate it here. So the first part +gives me 1 over e to x^2. + + align:start position:0% +gives me 1 over e to x^2. + + + align:start position:0% +gives me 1 over e to x^2. +And then I have to take the derivative + + align:start position:0% +And then I have to take the derivative + + + align:start position:0% +And then I have to take the derivative +of the next inside function which the + + align:start position:0% +of the next inside function which the + + + align:start position:0% +of the next inside function which the +next one inside after natural log is e + + align:start position:0% +next one inside after natural log is e + + + align:start position:0% +next one inside after natural log is e +to the x^2. And the derivative of that + + align:start position:0% +to the x^2. And the derivative of that + + + align:start position:0% +to the x^2. And the derivative of that +I'm going to do another chain rule. I + + align:start position:0% +I'm going to do another chain rule. I + + + align:start position:0% +I'm going to do another chain rule. I +get e to the x^2 + + align:start position:0% +get e to the x^2 + + + align:start position:0% +get e to the x^2 +times the derivative of this x^2 which + + align:start position:0% +times the derivative of this x^2 which + + + align:start position:0% +times the derivative of this x^2 which +is 2x. + + align:start position:0% +is 2x. + + + align:start position:0% +is 2x. +Okay. So again this part is the + + align:start position:0% +Okay. So again this part is the + + + align:start position:0% +Okay. So again this part is the +derivative of the natural log evaluated + + align:start position:0% +derivative of the natural log evaluated + + + align:start position:0% +derivative of the natural log evaluated +at e x^2. This part is the derivative of + + align:start position:0% +at e x^2. This part is the derivative of + + + align:start position:0% +at e x^2. This part is the derivative of +e x^2. This one comes just from the + + align:start position:0% +e x^2. This one comes just from the + + + align:start position:0% +e x^2. This one comes just from the +derivative of e to the x is e to the x + + align:start position:0% +derivative of e to the x is e to the x + + + align:start position:0% +derivative of e to the x is e to the x +and then so I evaluated at x^2 and then + + align:start position:0% +and then so I evaluated at x^2 and then + + + align:start position:0% +and then so I evaluated at x^2 and then +this is the derivative of the x squ + + align:start position:0% +this is the derivative of the x squ + + + align:start position:0% +this is the derivative of the x squ +part. So I end up with product of three + + align:start position:0% +part. So I end up with product of three + + + align:start position:0% +part. So I end up with product of three +functions because I have a composition + + align:start position:0% +functions because I have a composition + + + align:start position:0% +functions because I have a composition +of three functions. So I have to do the + + align:start position:0% +of three functions. So I have to do the + + + align:start position:0% +of three functions. So I have to do the +chain rule with three different pieces + + align:start position:0% +chain rule with three different pieces + + + align:start position:0% +chain rule with three different pieces +basically. So, but this simplifies, + + align:start position:0% +basically. So, but this simplifies, + + + align:start position:0% +basically. So, but this simplifies, +right? EX^2 / EX2 is 1. So, I get 2x. + + align:start position:0% +right? EX^2 / EX2 is 1. So, I get 2x. + + + align:start position:0% +right? EX^2 / EX2 is 1. So, I get 2x. +Okay. So, what's the fast way? That's + + align:start position:0% +Okay. So, what's the fast way? That's + + + align:start position:0% +Okay. So, what's the fast way? That's +that's our answer. 2x. But what's the + + align:start position:0% +that's our answer. 2x. But what's the + + + align:start position:0% +that's our answer. 2x. But what's the +fast way? + + align:start position:0% + + + + align:start position:0% + +Well, the fast way is to recognize that + + align:start position:0% +Well, the fast way is to recognize that + + + align:start position:0% +Well, the fast way is to recognize that +natural log of e to x^2. Let me erase + + align:start position:0% +natural log of e to x^2. Let me erase + + + align:start position:0% +natural log of e to x^2. Let me erase +the y here. e to the x^2 is equal to + + align:start position:0% +the y here. e to the x^2 is equal to + + + align:start position:0% +the y here. e to the x^2 is equal to +x^2. + + align:start position:0% +x^2. + + + align:start position:0% +x^2. +Okay. Why is that? That's because + + align:start position:0% +Okay. Why is that? That's because + + + align:start position:0% +Okay. Why is that? That's because +natural log function is the inverse of + + align:start position:0% +natural log function is the inverse of + + + align:start position:0% +natural log function is the inverse of +the exponential function with base e, + + align:start position:0% +the exponential function with base e, + + + align:start position:0% +the exponential function with base e, +right? This is something you've you've + + align:start position:0% +right? This is something you've you've + + + align:start position:0% +right? This is something you've you've +talked about before. So this means that + + align:start position:0% +talked about before. So this means that + + + align:start position:0% +talked about before. So this means that +if I take natural log of e to anything + + align:start position:0% +if I take natural log of e to anything + + + align:start position:0% +if I take natural log of e to anything +here, I'm going to get I'm going to get + + align:start position:0% +here, I'm going to get I'm going to get + + + align:start position:0% +here, I'm going to get I'm going to get +that thing right there, whatever that + + align:start position:0% +that thing right there, whatever that + + + align:start position:0% +that thing right there, whatever that +function is. So natural log of e to the + + align:start position:0% +function is. So natural log of e to the + + + align:start position:0% +function is. So natural log of e to the +x^2 is x^2. Okay? If if you don't like + + align:start position:0% +x^2 is x^2. Okay? If if you don't like + + + align:start position:0% +x^2 is x^2. Okay? If if you don't like +to talk about it that way, if you don't + + align:start position:0% +to talk about it that way, if you don't + + + align:start position:0% +to talk about it that way, if you don't +like inverse functions, uh you can use + + align:start position:0% +like inverse functions, uh you can use + + + align:start position:0% +like inverse functions, uh you can use +one of the rules of logarithms which + + align:start position:0% +one of the rules of logarithms which + + + align:start position:0% +one of the rules of logarithms which +says that this expression is equal to + + align:start position:0% +says that this expression is equal to + + + align:start position:0% +says that this expression is equal to +x^2 time natural log of e. + + align:start position:0% +x^2 time natural log of e. + + + align:start position:0% +x^2 time natural log of e. +That's another way to think about this + + align:start position:0% +That's another way to think about this + + + align:start position:0% +That's another way to think about this +problem. And then you should remember + + align:start position:0% +problem. And then you should remember + + + align:start position:0% +problem. And then you should remember +that natural log of e is equal to 1. So + + align:start position:0% +that natural log of e is equal to 1. So + + + align:start position:0% +that natural log of e is equal to 1. So +at some point you have to uh you have to + + align:start position:0% +at some point you have to uh you have to + + + align:start position:0% +at some point you have to uh you have to +know uh a little bit about logs and + + align:start position:0% +know uh a little bit about logs and + + + align:start position:0% +know uh a little bit about logs and +exponentials. But the thing to recognize + + align:start position:0% +exponentials. But the thing to recognize + + + align:start position:0% +exponentials. But the thing to recognize +is that h of x is just a fancy way of + + align:start position:0% +is that h of x is just a fancy way of + + + align:start position:0% +is that h of x is just a fancy way of +writing x^2. And so the derivative of + + align:start position:0% +writing x^2. And so the derivative of + + + align:start position:0% +writing x^2. And so the derivative of +x^2 + + align:start position:0% +x^2 + + + align:start position:0% +x^2 +is 2x. So sometimes it's better to see + + align:start position:0% +is 2x. So sometimes it's better to see + + + align:start position:0% +is 2x. So sometimes it's better to see +what can what can be done to make the + + align:start position:0% +what can what can be done to make the + + + align:start position:0% +what can what can be done to make the +problem a little easier. But that is + + align:start position:0% +problem a little easier. But that is + + + align:start position:0% +problem a little easier. But that is +where we will stop with these. \ No newline at end of file diff --git a/xZ72LPLHVSY.txt b/xZ72LPLHVSY.txt new file mode 100644 index 0000000000000000000000000000000000000000..d0484d8a2d647abaf77cccb876db1fd133efb3d3 --- /dev/null +++ b/xZ72LPLHVSY.txt @@ -0,0 +1,7715 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT opencourseware continue to + + align:start position:0% +will help MIT opencourseware continue to + + + align:start position:0% +will help MIT opencourseware continue to +offer high quality educational resources + + align:start position:0% +offer high quality educational resources + + + align:start position:0% +offer high quality educational resources +for free + + align:start position:0% +for free + + + align:start position:0% +for free +to make a donation or view additional + + align:start position:0% +to make a donation or view additional + + + align:start position:0% +to make a donation or view additional +materials from hundreds of MIT courses + + align:start position:0% +materials from hundreds of MIT courses + + + align:start position:0% +materials from hundreds of MIT courses +visit MIT opencourseware at ocw.mit.edu + + align:start position:0% + + + + align:start position:0% + +this is where we ended last time we had + + align:start position:0% +this is where we ended last time we had + + + align:start position:0% +this is where we ended last time we had +just + + align:start position:0% +just + + + align:start position:0% +just +talked about these major types of + + align:start position:0% +talked about these major types of + + + align:start position:0% +talked about these major types of +functions + + align:start position:0% +functions + + + align:start position:0% +functions +of neocortex + + align:start position:0% + + + + align:start position:0% + +and I've named them according to how I + + align:start position:0% +and I've named them according to how I + + + align:start position:0% +and I've named them according to how I +think it evolved + + align:start position:0% + + + + align:start position:0% + +location sense object sense + + align:start position:0% +location sense object sense + + + align:start position:0% +location sense object sense +functions of the prefrontally + + align:start position:0% +functions of the prefrontally + + + align:start position:0% +functions of the prefrontally +laborations of motor cortex for planning + + align:start position:0% +laborations of motor cortex for planning + + + align:start position:0% +laborations of motor cortex for planning +and I'm going to go through that a + + align:start position:0% +and I'm going to go through that a + + + align:start position:0% +and I'm going to go through that a +little more and that's basically what + + align:start position:0% +little more and that's basically what + + + align:start position:0% +little more and that's basically what +these questions are about + + align:start position:0% +these questions are about + + + align:start position:0% +these questions are about +we had talked about the campus system + + align:start position:0% + + + + align:start position:0% + +um I want you to think about how that + + align:start position:0% +um I want you to think about how that + + + align:start position:0% +um I want you to think about how that +facilitates the ability to anticipate to + + align:start position:0% +facilitates the ability to anticipate to + + + align:start position:0% +facilitates the ability to anticipate to +stimuli that you're about to encounter + + align:start position:0% +stimuli that you're about to encounter + + + align:start position:0% +stimuli that you're about to encounter +any animal is going to encounter how + + align:start position:0% +any animal is going to encounter how + + + align:start position:0% +any animal is going to encounter how +does that location information that is + + align:start position:0% +does that location information that is + + + align:start position:0% +does that location information that is +handled by the campus remember + + align:start position:0% +handled by the campus remember + + + align:start position:0% +handled by the campus remember +how it evolved + + align:start position:0% +how it evolved + + + align:start position:0% +how it evolved +to know where the animal is in the local + + align:start position:0% +to know where the animal is in the local + + + align:start position:0% +to know where the animal is in the local +environment and eventually in many + + align:start position:0% +environment and eventually in many + + + align:start position:0% +environment and eventually in many +different local environments and we + + align:start position:0% +different local environments and we + + + align:start position:0% +different local environments and we +remember them + + align:start position:0% +remember them + + + align:start position:0% +remember them +our prior to Cortex remembers them + + align:start position:0% +our prior to Cortex remembers them + + + align:start position:0% +our prior to Cortex remembers them +so the hippocampus doesn't have to + + align:start position:0% +so the hippocampus doesn't have to + + + align:start position:0% +so the hippocampus doesn't have to +totally relearn it every time + + align:start position:0% +totally relearn it every time + + + align:start position:0% +totally relearn it every time +you go to a different area but because + + align:start position:0% +you go to a different area but because + + + align:start position:0% +you go to a different area but because +every time you turn your head the way + + align:start position:0% +every time you turn your head the way + + + align:start position:0% +every time you turn your head the way +that system works + + align:start position:0% + + + + align:start position:0% + +this information + + align:start position:0% +this information + + + align:start position:0% +this information +is sent from hippocampus + + align:start position:0% +is sent from hippocampus + + + align:start position:0% +is sent from hippocampus +back to the mammary buddies that means + + align:start position:0% +back to the mammary buddies that means + + + align:start position:0% +back to the mammary buddies that means +the hippocampus is getting that + + align:start position:0% +the hippocampus is getting that + + + align:start position:0% +the hippocampus is getting that +information based on where + + align:start position:0% +information based on where + + + align:start position:0% +information based on where +the direction we're looking so it can + + align:start position:0% +the direction we're looking so it can + + + align:start position:0% +the direction we're looking so it can +call up all the relevant memories + + align:start position:0% +call up all the relevant memories + + + align:start position:0% +call up all the relevant memories +the things in front of us + + align:start position:0% +the things in front of us + + + align:start position:0% +the things in front of us +so it's a major factor in what how the + + align:start position:0% +so it's a major factor in what how the + + + align:start position:0% +so it's a major factor in what how the +motivations make us decide to go in One + + align:start position:0% +motivations make us decide to go in One + + + align:start position:0% +motivations make us decide to go in One +Direction or another or in an animal I + + align:start position:0% +Direction or another or in an animal I + + + align:start position:0% +Direction or another or in an animal I +shouldn't say humans primarily but + + align:start position:0% + + + + align:start position:0% + +it's for navigating the world and that + + align:start position:0% +it's for navigating the world and that + + + align:start position:0% +it's for navigating the world and that +we know that motivation is a major + + align:start position:0% +we know that motivation is a major + + + align:start position:0% +we know that motivation is a major +factor and people haven't considered + + align:start position:0% +factor and people haven't considered + + + align:start position:0% +factor and people haven't considered +enough you know the role of the + + align:start position:0% +enough you know the role of the + + + align:start position:0% +enough you know the role of the +hippocampus and motivation + + align:start position:0% +hippocampus and motivation + + + align:start position:0% +hippocampus and motivation +and why this whole system for memory + + align:start position:0% +and why this whole system for memory + + + align:start position:0% +and why this whole system for memory +long-term memory evolved within hit the + + align:start position:0% +long-term memory evolved within hit the + + + align:start position:0% +long-term memory evolved within hit the +campus that within the limbic system + + align:start position:0% +campus that within the limbic system + + + align:start position:0% +campus that within the limbic system +basically + + align:start position:0% +basically + + + align:start position:0% +basically +but anyway uh + + align:start position:0% +but anyway uh + + + align:start position:0% +but anyway uh +and you need to contrast that with the + + align:start position:0% + + + + align:start position:0% + +the kind of anticipatory activity that + + align:start position:0% +the kind of anticipatory activity that + + + align:start position:0% +the kind of anticipatory activity that +these parietal and temples association + + align:start position:0% +these parietal and temples association + + + align:start position:0% +these parietal and temples association +areas are concern with so we'll be + + align:start position:0% +areas are concern with so we'll be + + + align:start position:0% +areas are concern with so we'll be +talking more about that + + align:start position:0% +talking more about that + + + align:start position:0% +talking more about that +so this is a + + align:start position:0% +so this is a + + + align:start position:0% +so this is a +it's all in the book and it's just a + + align:start position:0% +it's all in the book and it's just a + + + align:start position:0% +it's all in the book and it's just a +different way of looking at it in these + + align:start position:0% +different way of looking at it in these + + + align:start position:0% +different way of looking at it in these +slides where I summarize these major + + align:start position:0% +slides where I summarize these major + + + align:start position:0% +slides where I summarize these major +points + + align:start position:0% + + + + align:start position:0% + +made I think anticipation ability to + + align:start position:0% +made I think anticipation ability to + + + align:start position:0% +made I think anticipation ability to +anticipate + + align:start position:0% +anticipate + + + align:start position:0% +anticipate +stimuli ability to plan movements and + + align:start position:0% +stimuli ability to plan movements and + + + align:start position:0% +stimuli ability to plan movements and +other kind of anticipation + + align:start position:0% +other kind of anticipation + + + align:start position:0% +other kind of anticipation +uh + + align:start position:0% +uh + + + align:start position:0% +uh +or major Innovations of the cortex + + align:start position:0% +or major Innovations of the cortex + + + align:start position:0% +or major Innovations of the cortex +it's not what the tectum does + + align:start position:0% +it's not what the tectum does + + + align:start position:0% +it's not what the tectum does +it's not what subcortical systems do + + align:start position:0% +it's not what subcortical systems do + + + align:start position:0% +it's not what subcortical systems do +this thankful aspect is so important for + + align:start position:0% +this thankful aspect is so important for + + + align:start position:0% +this thankful aspect is so important for +new quotas of course planning you know + + align:start position:0% +new quotas of course planning you know + + + align:start position:0% +new quotas of course planning you know +how important we frontal + + align:start position:0% +how important we frontal + + + align:start position:0% +how important we frontal +areas are + + align:start position:0% +areas are + + + align:start position:0% +areas are +they appear to be evolved well you could + + align:start position:0% +they appear to be evolved well you could + + + align:start position:0% +they appear to be evolved well you could +say that in that associate the + + align:start position:0% +say that in that associate the + + + align:start position:0% +say that in that associate the +multimodal original multimodal cortex + + align:start position:0% +multimodal original multimodal cortex + + + align:start position:0% +multimodal original multimodal cortex +the motor cortex evolve very early + + align:start position:0% +the motor cortex evolve very early + + + align:start position:0% +the motor cortex evolve very early +initially as much sense Justice in + + align:start position:0% +initially as much sense Justice in + + + align:start position:0% +initially as much sense Justice in +another Century here but once it became + + align:start position:0% +another Century here but once it became + + + align:start position:0% +another Century here but once it became +specialized for + + align:start position:0% +specialized for + + + align:start position:0% +specialized for +control of movement + + align:start position:0% +control of movement + + + align:start position:0% +control of movement +then the areas near it became involved + + align:start position:0% +then the areas near it became involved + + + align:start position:0% +then the areas near it became involved +in + + align:start position:0% +in + + + align:start position:0% +in +anticipating movement namely planning it + + align:start position:0% +anticipating movement namely planning it + + + align:start position:0% +anticipating movement namely planning it +and uh + + align:start position:0% + + + + align:start position:0% + +this is uh + + align:start position:0% +this is uh + + + align:start position:0% +this is uh +mostly Theory but I mentioned here + + align:start position:0% +mostly Theory but I mentioned here + + + align:start position:0% +mostly Theory but I mentioned here +support for it the laboratory studies of + + align:start position:0% +support for it the laboratory studies of + + + align:start position:0% +support for it the laboratory studies of +suck love in Moscow back in the 60s he + + align:start position:0% +suck love in Moscow back in the 60s he + + + align:start position:0% +suck love in Moscow back in the 60s he +made did extensive studies of reactions + + align:start position:0% +made did extensive studies of reactions + + + align:start position:0% +made did extensive studies of reactions +of humans to novelty and he studied + + align:start position:0% +of humans to novelty and he studied + + + align:start position:0% +of humans to novelty and he studied +animals as well + + align:start position:0% +animals as well + + + align:start position:0% +animals as well +and how any kind of unexpected input + + align:start position:0% +and how any kind of unexpected input + + + align:start position:0% +and how any kind of unexpected input +even if it was an unexpected lack of + + align:start position:0% +even if it was an unexpected lack of + + + align:start position:0% +even if it was an unexpected lack of +input it could cause an arousal response + + align:start position:0% +input it could cause an arousal response + + + align:start position:0% +input it could cause an arousal response +that alter the electrical activity of + + align:start position:0% +that alter the electrical activity of + + + align:start position:0% +that alter the electrical activity of +the neocortex + + align:start position:0% + + + + align:start position:0% + +and when the inputs become familiar then + + align:start position:0% +and when the inputs become familiar then + + + align:start position:0% +and when the inputs become familiar then +you don't get those arousal effects + + align:start position:0% + + + + align:start position:0% + +so he CLA he in theoretical terms he + + align:start position:0% +so he CLA he in theoretical terms he + + + align:start position:0% +so he CLA he in theoretical terms he +said this these the + + align:start position:0% +said this these the + + + align:start position:0% +said this these the +there was a central model this is how + + align:start position:0% +there was a central model this is how + + + align:start position:0% +there was a central model this is how +the brain is simulating what's going on + + align:start position:0% +the brain is simulating what's going on + + + align:start position:0% +the brain is simulating what's going on +when you're dreaming all you're doing is + + align:start position:0% +when you're dreaming all you're doing is + + + align:start position:0% +when you're dreaming all you're doing is +using that system + + align:start position:0% +using that system + + + align:start position:0% +using that system +your brain is totally capable of + + align:start position:0% +your brain is totally capable of + + + align:start position:0% +your brain is totally capable of +simulating the environment in incredible + + align:start position:0% +simulating the environment in incredible + + + align:start position:0% +simulating the environment in incredible +detail have you ever had + + align:start position:0% +detail have you ever had + + + align:start position:0% +detail have you ever had +hypnagogic imagery in or visit dreaming + + align:start position:0% +hypnagogic imagery in or visit dreaming + + + align:start position:0% +hypnagogic imagery in or visit dreaming +where you actually + + align:start position:0% +where you actually + + + align:start position:0% +where you actually +don't know for sure that you're dreaming + + align:start position:0% +don't know for sure that you're dreaming + + + align:start position:0% +don't know for sure that you're dreaming +you know you see cartoons of people + + align:start position:0% +you know you see cartoons of people + + + align:start position:0% +you know you see cartoons of people +pinching themselves to see if they're + + align:start position:0% +pinching themselves to see if they're + + + align:start position:0% +pinching themselves to see if they're +asleep have you ever had such vivid + + align:start position:0% +asleep have you ever had such vivid + + + align:start position:0% +asleep have you ever had such vivid +dreams that you couldn't tell + + align:start position:0% +dreams that you couldn't tell + + + align:start position:0% +dreams that you couldn't tell +does everybody had some people don't or + + align:start position:0% +does everybody had some people don't or + + + align:start position:0% +does everybody had some people don't or +at least they don't remember but I've + + align:start position:0% +at least they don't remember but I've + + + align:start position:0% +at least they don't remember but I've +had them and they're really not very + + align:start position:0% +had them and they're really not very + + + align:start position:0% +had them and they're really not very +many and only when I was younger + + align:start position:0% +many and only when I was younger + + + align:start position:0% +many and only when I was younger +most of the time I don't have difficulty + + align:start position:0% +most of the time I don't have difficulty + + + align:start position:0% +most of the time I don't have difficulty +knowing that I'm dreaming + + align:start position:0% +knowing that I'm dreaming + + + align:start position:0% +knowing that I'm dreaming +okay + + align:start position:0% + + + + align:start position:0% + +dreaming that you + + align:start position:0% +dreaming that you + + + align:start position:0% +dreaming that you +have supported by me + + align:start position:0% +have supported by me + + + align:start position:0% +have supported by me +yeah that's an anxiety dream but in + + align:start position:0% +yeah that's an anxiety dream but in + + + align:start position:0% +yeah that's an anxiety dream but in +hypnagogic imagery it's a good question + + align:start position:0% +hypnagogic imagery it's a good question + + + align:start position:0% +hypnagogic imagery it's a good question +I don't know we should look there is a + + align:start position:0% +I don't know we should look there is a + + + align:start position:0% +I don't know we should look there is a +literature on it you can read about it + + align:start position:0% +literature on it you can read about it + + + align:start position:0% +literature on it you can read about it +and uh + + align:start position:0% +and uh + + + align:start position:0% +and uh +how + + align:start position:0% +how + + + align:start position:0% +how +do all the senses come to play + + align:start position:0% +do all the senses come to play + + + align:start position:0% +do all the senses come to play +you know I remember when I had an + + align:start position:0% +you know I remember when I had an + + + align:start position:0% +you know I remember when I had an +auditory visual it's not a sensory they + + align:start position:0% +auditory visual it's not a sensory they + + + align:start position:0% +auditory visual it's not a sensory they +were all there I cannot remember any + + align:start position:0% +were all there I cannot remember any + + + align:start position:0% +were all there I cannot remember any +olfactory imagery + + align:start position:0% +olfactory imagery + + + align:start position:0% +olfactory imagery +I'm not saying it's not possible in some + + align:start position:0% +I'm not saying it's not possible in some + + + align:start position:0% +I'm not saying it's not possible in some +people but + + align:start position:0% +people but + + + align:start position:0% +people but +often it's true that some of the + + align:start position:0% +often it's true that some of the + + + align:start position:0% +often it's true that some of the +modalities are missing + + align:start position:0% +modalities are missing + + + align:start position:0% +modalities are missing +and what you asked about emotion + + align:start position:0% +and what you asked about emotion + + + align:start position:0% +and what you asked about emotion +that's a major issue you know in that + + align:start position:0% +that's a major issue you know in that + + + align:start position:0% +that's a major issue you know in that +kind of imagery + + align:start position:0% +kind of imagery + + + align:start position:0% +kind of imagery +because of it involves these + + align:start position:0% +because of it involves these + + + align:start position:0% +because of it involves these +association areas posterior cortex + + align:start position:0% +association areas posterior cortex + + + align:start position:0% +association areas posterior cortex +Generations + + align:start position:0% +Generations + + + align:start position:0% +Generations +images of the world us through the + + align:start position:0% +images of the world us through the + + + align:start position:0% +images of the world us through the +parietal primarily + + align:start position:0% +parietal primarily + + + align:start position:0% +parietal primarily +uh + + align:start position:0% + + + + align:start position:0% + +the connections to emotion could be + + align:start position:0% +the connections to emotion could be + + + align:start position:0% +the connections to emotion could be +missing and it could still generate + + align:start position:0% +missing and it could still generate + + + align:start position:0% +missing and it could still generate +these images + + align:start position:0% +these images + + + align:start position:0% +these images +so + + align:start position:0% + + + + align:start position:0% + +if I have another one I'll I'll do the + + align:start position:0% +if I have another one I'll I'll do the + + + align:start position:0% +if I have another one I'll I'll do the +investigation + + align:start position:0% +investigation + + + align:start position:0% +investigation +anyway + + align:start position:0% + + + + align:start position:0% + +so that same model + + align:start position:0% + + + + align:start position:0% + +can control endogenous generation of + + align:start position:0% +can control endogenous generation of + + + align:start position:0% +can control endogenous generation of +actions this is the way the frontal + + align:start position:0% +actions this is the way the frontal + + + align:start position:0% +actions this is the way the frontal +areas in the posterior areas that do + + align:start position:0% +areas in the posterior areas that do + + + align:start position:0% +areas in the posterior areas that do +this kind of simulation of the world or + + align:start position:0% +this kind of simulation of the world or + + + align:start position:0% +this kind of simulation of the world or +connect + + align:start position:0% +connect + + + align:start position:0% +connect +you can use that model to plan your + + align:start position:0% +you can use that model to plan your + + + align:start position:0% +you can use that model to plan your +actions and we do it all the time + + align:start position:0% +actions and we do it all the time + + + align:start position:0% +actions and we do it all the time +it's a view that became unpopular for a + + align:start position:0% +it's a view that became unpopular for a + + + align:start position:0% +it's a view that became unpopular for a +while although back in the 60s + + align:start position:0% +while although back in the 60s + + + align:start position:0% +while although back in the 60s +Makai developed it + + align:start position:0% +Makai developed it + + + align:start position:0% +Makai developed it +but more recently it's been + + align:start position:0% +but more recently it's been + + + align:start position:0% +but more recently it's been +people have come back to it and they've + + align:start position:0% +people have come back to it and they've + + + align:start position:0% +people have come back to it and they've +updated it there was a whole issue of + + align:start position:0% +updated it there was a whole issue of + + + align:start position:0% +updated it there was a whole issue of +I think the journal several contracts + + align:start position:0% +I think the journal several contracts + + + align:start position:0% +I think the journal several contracts +one of these major journals that talks + + align:start position:0% +one of these major journals that talks + + + align:start position:0% +one of these major journals that talks +about cortex so + + align:start position:0% +about cortex so + + + align:start position:0% +about cortex so +had a whole issue on this + + align:start position:0% +had a whole issue on this + + + align:start position:0% +had a whole issue on this +I think I mentioned it and look I'm + + align:start position:0% +I think I mentioned it and look I'm + + + align:start position:0% +I think I mentioned it and look I'm +remembering right + + align:start position:0% +remembering right + + + align:start position:0% +remembering right +okay uh + + align:start position:0% +okay uh + + + align:start position:0% +okay uh +so now we've not mentioned throughout + + align:start position:0% +so now we've not mentioned throughout + + + align:start position:0% +so now we've not mentioned throughout +them in this actually both this + + align:start position:0% +them in this actually both this + + + align:start position:0% +them in this actually both this +throughout them and the cortex expanded + + align:start position:0% +throughout them and the cortex expanded + + + align:start position:0% +throughout them and the cortex expanded +in evolution including recent evolution + + align:start position:0% +in evolution including recent evolution + + + align:start position:0% +in evolution including recent evolution +they can operate relatively + + align:start position:0% +they can operate relatively + + + align:start position:0% +they can operate relatively +independently and that's because + + align:start position:0% +independently and that's because + + + align:start position:0% +independently and that's because +they don't operate independently in + + align:start position:0% +they don't operate independently in + + + align:start position:0% +they don't operate independently in +humans at all + + align:start position:0% +humans at all + + + align:start position:0% +humans at all +but in animals it's quite possible for + + align:start position:0% +but in animals it's quite possible for + + + align:start position:0% +but in animals it's quite possible for +them to operate independently you can + + align:start position:0% +them to operate independently you can + + + align:start position:0% +them to operate independently you can +have an animal + + align:start position:0% +have an animal + + + align:start position:0% +have an animal +uh + + align:start position:0% +uh + + + align:start position:0% +uh +where much of the cortex is rendered + + align:start position:0% +where much of the cortex is rendered + + + align:start position:0% +where much of the cortex is rendered +non-functional and he can still use his + + align:start position:0% +non-functional and he can still use his + + + align:start position:0% +non-functional and he can still use his +striatal system why is that + + align:start position:0% +striatal system why is that + + + align:start position:0% +striatal system why is that +how is the striatoman getting its inputs + + align:start position:0% + + + + align:start position:0% + +where does it get its input so they + + align:start position:0% +where does it get its input so they + + + align:start position:0% +where does it get its input so they +don't come from the cortex + + align:start position:0% + + + + align:start position:0% + +remember it they come from the older + + align:start position:0% +remember it they come from the older + + + align:start position:0% +remember it they come from the older +parts of the thalamus + + align:start position:0% +parts of the thalamus + + + align:start position:0% +parts of the thalamus +the + + align:start position:0% +the + + + align:start position:0% +the +the nuclei we call the intralaminer in + + align:start position:0% +the nuclei we call the intralaminer in + + + align:start position:0% +the nuclei we call the intralaminer in +midline nuclei they're mostly getting + + align:start position:0% +midline nuclei they're mostly getting + + + align:start position:0% +midline nuclei they're mostly getting +multimodal input + + align:start position:0% +multimodal input + + + align:start position:0% +multimodal input +but some of those nuclei are more + + align:start position:0% +but some of those nuclei are more + + + align:start position:0% +but some of those nuclei are more +dominated by + + align:start position:0% +dominated by + + + align:start position:0% +dominated by +the visual areas of the tectum they're + + align:start position:0% +the visual areas of the tectum they're + + + align:start position:0% +the visual areas of the tectum they're +getting a lot of input from the app + + align:start position:0% +getting a lot of input from the app + + + align:start position:0% +getting a lot of input from the app +detecting + + align:start position:0% +detecting + + + align:start position:0% +detecting +the somatosensory system Pathways don't + + align:start position:0% +the somatosensory system Pathways don't + + + align:start position:0% +the somatosensory system Pathways don't +all come through detectives some of them + + align:start position:0% +all come through detectives some of them + + + align:start position:0% +all come through detectives some of them +come directly from the spinal thalamic + + align:start position:0% +come directly from the spinal thalamic + + + align:start position:0% +come directly from the spinal thalamic +trait + + align:start position:0% + + + + align:start position:0% + +uh + + align:start position:0% + + + + align:start position:0% + +and auditory inputs also reach those and + + align:start position:0% +and auditory inputs also reach those and + + + align:start position:0% +and auditory inputs also reach those and +in addition to the interlaminary midline + + align:start position:0% +in addition to the interlaminary midline + + + align:start position:0% +in addition to the interlaminary midline +nuclei there are + + align:start position:0% +nuclei there are + + + align:start position:0% +nuclei there are +what appear to be older + + align:start position:0% +what appear to be older + + + align:start position:0% +what appear to be older +parts of the thalamus and the posterior + + align:start position:0% +parts of the thalamus and the posterior + + + align:start position:0% +parts of the thalamus and the posterior +Thalamus was a group of nuclei sort of + + align:start position:0% +Thalamus was a group of nuclei sort of + + + align:start position:0% +Thalamus was a group of nuclei sort of +in the interstices between the visuals + + align:start position:0% +in the interstices between the visuals + + + align:start position:0% +in the interstices between the visuals +meta sensory and auditory the main + + align:start position:0% +meta sensory and auditory the main + + + align:start position:0% +meta sensory and auditory the main +nuclei we consider to be involved in + + align:start position:0% +nuclei we consider to be involved in + + + align:start position:0% +nuclei we consider to be involved in +those three senses + + align:start position:0% +those three senses + + + align:start position:0% +those three senses +but outside those nuclei there's the + + align:start position:0% +but outside those nuclei there's the + + + align:start position:0% +but outside those nuclei there's the +posterior group of nuclei it's basically + + align:start position:0% +posterior group of nuclei it's basically + + + align:start position:0% +posterior group of nuclei it's basically +multimodal cells + + align:start position:0% +multimodal cells + + + align:start position:0% +multimodal cells +that project to multimodal cortical + + align:start position:0% +that project to multimodal cortical + + + align:start position:0% +that project to multimodal cortical +areas + + align:start position:0% +areas + + + align:start position:0% +areas +okay well we'll be talking more about + + align:start position:0% +okay well we'll be talking more about + + + align:start position:0% +okay well we'll be talking more about +that in a minute but + + align:start position:0% + + + + align:start position:0% + +how did the cortex expand we've talked + + align:start position:0% +how did the cortex expand we've talked + + + align:start position:0% +how did the cortex expand we've talked +about this before + + align:start position:0% + + + + align:start position:0% + +it expanded by individual areas getting + + align:start position:0% +it expanded by individual areas getting + + + align:start position:0% +it expanded by individual areas getting +a lot bigger + + align:start position:0% +a lot bigger + + + align:start position:0% +a lot bigger +like this dried area especially the + + align:start position:0% +like this dried area especially the + + + align:start position:0% +like this dried area especially the +fobial area got quite large like here in + + align:start position:0% +fobial area got quite large like here in + + + align:start position:0% +fobial area got quite large like here in +the + + align:start position:0% +the + + + align:start position:0% +the +in the owl monkey but it also there's + + align:start position:0% +in the owl monkey but it also there's + + + align:start position:0% +in the owl monkey but it also there's +been a multiplication of different + + align:start position:0% +been a multiplication of different + + + align:start position:0% +been a multiplication of different +representations of the same sensory + + align:start position:0% +representations of the same sensory + + + align:start position:0% +representations of the same sensory +surface so in this case the retina and + + align:start position:0% +surface so in this case the retina and + + + align:start position:0% +surface so in this case the retina and +it's represented in + + align:start position:0% +it's represented in + + + align:start position:0% +it's represented in +in different ways and sometimes we don't + + align:start position:0% +in different ways and sometimes we don't + + + align:start position:0% +in different ways and sometimes we don't +understand the functional differences in + + align:start position:0% +understand the functional differences in + + + align:start position:0% +understand the functional differences in +some cases we do understand + + align:start position:0% +some cases we do understand + + + align:start position:0% +some cases we do understand +and that's an area that the functional + + align:start position:0% +and that's an area that the functional + + + align:start position:0% +and that's an area that the functional +Imaging work in recent years has + + align:start position:0% +Imaging work in recent years has + + + align:start position:0% +Imaging work in recent years has +contributed quite a bit to for + + align:start position:0% +contributed quite a bit to for + + + align:start position:0% +contributed quite a bit to for +understands in the human brain + + align:start position:0% + + + + align:start position:0% + +so what was probably the earliest + + align:start position:0% +so what was probably the earliest + + + align:start position:0% +so what was probably the earliest +parcellation of the pallium + + align:start position:0% +parcellation of the pallium + + + align:start position:0% +parcellation of the pallium +isolation meaning it gets divided into + + align:start position:0% +isolation meaning it gets divided into + + + align:start position:0% +isolation meaning it gets divided into +different parts + + align:start position:0% +different parts + + + align:start position:0% +different parts +how did the pallium get started + + align:start position:0% + + + + align:start position:0% + +the whole end brain initially + + align:start position:0% +the whole end brain initially + + + align:start position:0% +the whole end brain initially +grew out of the olfactory system + + align:start position:0% +grew out of the olfactory system + + + align:start position:0% +grew out of the olfactory system +was totally dominated by olfaction + + align:start position:0% +was totally dominated by olfaction + + + align:start position:0% +was totally dominated by olfaction +this View + + align:start position:0% +this View + + + align:start position:0% +this View +is actually a common one + + align:start position:0% +is actually a common one + + + align:start position:0% +is actually a common one +it was + + align:start position:0% + + + + align:start position:0% + +argued by C Judson Herrick for example + + align:start position:0% +argued by C Judson Herrick for example + + + align:start position:0% +argued by C Judson Herrick for example +in the early part of the 20th century + + align:start position:0% +in the early part of the 20th century + + + align:start position:0% +in the early part of the 20th century +uh it was commonly believed but the + + align:start position:0% +uh it was commonly believed but the + + + align:start position:0% +uh it was commonly believed but the +evidence for it wasn't major they didn't + + align:start position:0% +evidence for it wasn't major they didn't + + + align:start position:0% +evidence for it wasn't major they didn't +know about some of the most primitive + + align:start position:0% +know about some of the most primitive + + + align:start position:0% +know about some of the most primitive +vertebrates + + align:start position:0% +vertebrates + + + align:start position:0% +vertebrates +so they used + + align:start position:0% +so they used + + + align:start position:0% +so they used +he used uh the tiger salamander more + + align:start position:0% +he used uh the tiger salamander more + + + align:start position:0% +he used uh the tiger salamander more +than any other animal + + align:start position:0% +than any other animal + + + align:start position:0% +than any other animal +and based a lot of his conclusions on + + align:start position:0% +and based a lot of his conclusions on + + + align:start position:0% +and based a lot of his conclusions on +what he found in the tiger salamander he + + align:start position:0% +what he found in the tiger salamander he + + + align:start position:0% +what he found in the tiger salamander he +also at that time they didn't have the + + align:start position:0% +also at that time they didn't have the + + + align:start position:0% +also at that time they didn't have the +really good experimental tracing methods + + align:start position:0% +really good experimental tracing methods + + + align:start position:0% +really good experimental tracing methods +for looking at connections + + align:start position:0% +for looking at connections + + + align:start position:0% +for looking at connections +but I have the big Advantage now in + + align:start position:0% +but I have the big Advantage now in + + + align:start position:0% +but I have the big Advantage now in +writing about this stuff in that they're + + align:start position:0% +writing about this stuff in that they're + + + align:start position:0% +writing about this stuff in that they're +the techniques are much more sensitive + + align:start position:0% +the techniques are much more sensitive + + + align:start position:0% +the techniques are much more sensitive +and they have been applied in a number + + align:start position:0% +and they have been applied in a number + + + align:start position:0% +and they have been applied in a number +of studies to some of these really + + align:start position:0% +of studies to some of these really + + + align:start position:0% +of studies to some of these really +primitive vertebrates + + align:start position:0% +primitive vertebrates + + + align:start position:0% +primitive vertebrates +and that's why I talked in the olfactory + + align:start position:0% +and that's why I talked in the olfactory + + + align:start position:0% +and that's why I talked in the olfactory +when we talked about olfactory system we + + align:start position:0% +when we talked about olfactory system we + + + align:start position:0% +when we talked about olfactory system we +talked about the + + align:start position:0% +talked about the + + + align:start position:0% +talked about the +the sea lampreys and the hagfish + + align:start position:0% +the sea lampreys and the hagfish + + + align:start position:0% +the sea lampreys and the hagfish +are more specialized so some people + + align:start position:0% +are more specialized so some people + + + align:start position:0% +are more specialized so some people +don't think they're very good model but + + align:start position:0% +don't think they're very good model but + + + align:start position:0% +don't think they're very good model but +in both of those animals + + align:start position:0% +in both of those animals + + + align:start position:0% +in both of those animals +olfaction + + align:start position:0% +olfaction + + + align:start position:0% +olfaction +olfactory projections go to everywhere + + align:start position:0% +olfactory projections go to everywhere + + + align:start position:0% +olfactory projections go to everywhere +in the end + + align:start position:0% +in the end + + + align:start position:0% +in the end +everywhere in fact they even go into the + + align:start position:0% +everywhere in fact they even go into the + + + align:start position:0% +everywhere in fact they even go into the +diencephalon + + align:start position:0% +diencephalon + + + align:start position:0% +diencephalon +directly from the olfactory bulbs + + align:start position:0% +directly from the olfactory bulbs + + + align:start position:0% +directly from the olfactory bulbs +so the earliest parcellation is + + align:start position:0% +so the earliest parcellation is + + + align:start position:0% +so the earliest parcellation is +separation of the olfactory + + align:start position:0% +separation of the olfactory + + + align:start position:0% +separation of the olfactory +inputs from the novel Factory that's the + + align:start position:0% +inputs from the novel Factory that's the + + + align:start position:0% +inputs from the novel Factory that's the +earliest persolation so if you look at + + align:start position:0% +earliest persolation so if you look at + + + align:start position:0% +earliest persolation so if you look at +the gene expression data you know in the + + align:start position:0% +the gene expression data you know in the + + + align:start position:0% +the gene expression data you know in the +sea lamprey + + align:start position:0% +sea lamprey + + + align:start position:0% +sea lamprey +there's it's been a little controversial + + align:start position:0% +there's it's been a little controversial + + + align:start position:0% +there's it's been a little controversial +with some varying results but people + + align:start position:0% +with some varying results but people + + + align:start position:0% +with some varying results but people +that have reviewed it + + align:start position:0% +that have reviewed it + + + align:start position:0% +that have reviewed it +that have gone over all of it and + + align:start position:0% +that have gone over all of it and + + + align:start position:0% +that have gone over all of it and +reviewed it carefully will tell you that + + align:start position:0% +reviewed it carefully will tell you that + + + align:start position:0% +reviewed it carefully will tell you that +there's at least two I mean + + align:start position:0% +there's at least two I mean + + + align:start position:0% +there's at least two I mean +types according to gene expression and + + align:start position:0% +types according to gene expression and + + + align:start position:0% +types according to gene expression and +it corresponds to the non-of-factory + + align:start position:0% +it corresponds to the non-of-factory + + + align:start position:0% +it corresponds to the non-of-factory +areas + + align:start position:0% + + + + align:start position:0% + +non-alfactional Factory + + align:start position:0% +non-alfactional Factory + + + align:start position:0% +non-alfactional Factory +okay so that was the earliest + + align:start position:0% +okay so that was the earliest + + + align:start position:0% +okay so that was the earliest +persolation do you know + + align:start position:0% +persolation do you know + + + align:start position:0% +persolation do you know +Italian + + align:start position:0% + + + + align:start position:0% + +and we know that that olfactory cortex + + align:start position:0% +and we know that that olfactory cortex + + + align:start position:0% +and we know that that olfactory cortex +doesn't get direct olfactory input from + + align:start position:0% +doesn't get direct olfactory input from + + + align:start position:0% +doesn't get direct olfactory input from +the olfactory bulbs right + + align:start position:0% +the olfactory bulbs right + + + align:start position:0% +the olfactory bulbs right +the factory bolts project directly to it + + align:start position:0% +the factory bolts project directly to it + + + align:start position:0% +the factory bolts project directly to it +but the part that the olfactory bulb + + align:start position:0% +but the part that the olfactory bulb + + + align:start position:0% +but the part that the olfactory bulb +doesn't project you + + align:start position:0% +doesn't project you + + + align:start position:0% +doesn't project you +it's dominated by their balance + + align:start position:0% + + + + align:start position:0% + +so then I asked about factors that + + align:start position:0% +so then I asked about factors that + + + align:start position:0% +so then I asked about factors that +include thalamic parcellation + + align:start position:0% +include thalamic parcellation + + + align:start position:0% +include thalamic parcellation +so we'll look at that + + align:start position:0% +so we'll look at that + + + align:start position:0% +so we'll look at that +and then I mentioned what you commonly + + align:start position:0% +and then I mentioned what you commonly + + + align:start position:0% +and then I mentioned what you commonly +hear and you'll probably hear it in + + align:start position:0% +hear and you'll probably hear it in + + + align:start position:0% +hear and you'll probably hear it in +medical schools if you take your Anatomy + + align:start position:0% +medical schools if you take your Anatomy + + + align:start position:0% +medical schools if you take your Anatomy +but these multimodal association areas + + align:start position:0% +but these multimodal association areas + + + align:start position:0% +but these multimodal association areas +are the most recent to evolve + + align:start position:0% + + + + align:start position:0% + +I would change that a little bit and say + + align:start position:0% +I would change that a little bit and say + + + align:start position:0% +I would change that a little bit and say +no + + align:start position:0% +no + + + align:start position:0% +no +they were probably the oldest type of + + align:start position:0% +they were probably the oldest type of + + + align:start position:0% +they were probably the oldest type of +Cortex but they're the most recent to + + align:start position:0% +Cortex but they're the most recent to + + + align:start position:0% +Cortex but they're the most recent to +really expand in the human brain + + align:start position:0% + + + + align:start position:0% + +because there's evidence that the + + align:start position:0% +because there's evidence that the + + + align:start position:0% +because there's evidence that the +unimodal areas + + align:start position:0% +unimodal areas + + + align:start position:0% +unimodal areas +are specialized evolved out of that + + align:start position:0% +are specialized evolved out of that + + + align:start position:0% +are specialized evolved out of that +multimodal periods + + align:start position:0% + + + + align:start position:0% + +if you look at the brains of + + align:start position:0% +if you look at the brains of + + + align:start position:0% +if you look at the brains of +some rodents that are a little more + + align:start position:0% +some rodents that are a little more + + + align:start position:0% +some rodents that are a little more +primitive in their structure like the + + align:start position:0% +primitive in their structure like the + + + align:start position:0% +primitive in their structure like the +Prairie Bowls have been studied well + + align:start position:0% +Prairie Bowls have been studied well + + + align:start position:0% +Prairie Bowls have been studied well +studied + + align:start position:0% +studied + + + align:start position:0% +studied +with this and look at the cortical unit + + align:start position:0% +with this and look at the cortical unit + + + align:start position:0% +with this and look at the cortical unit +recording work you'll find + + align:start position:0% +recording work you'll find + + + align:start position:0% +recording work you'll find +that + + align:start position:0% +that + + + align:start position:0% +that +there's a lot of multimodal input into + + align:start position:0% +there's a lot of multimodal input into + + + align:start position:0% +there's a lot of multimodal input into +areas that used to we used to think were + + align:start position:0% +areas that used to we used to think were + + + align:start position:0% +areas that used to we used to think were +we're unimodal they're multimodal and + + align:start position:0% +we're unimodal they're multimodal and + + + align:start position:0% +we're unimodal they're multimodal and +even in the primary sensory areas + + align:start position:0% +even in the primary sensory areas + + + align:start position:0% +even in the primary sensory areas +there's often more than one modality you + + align:start position:0% +there's often more than one modality you + + + align:start position:0% +there's often more than one modality you +find other modalities going right into + + align:start position:0% +find other modalities going right into + + + align:start position:0% +find other modalities going right into +auditory cortex and visual cortex for + + align:start position:0% +auditory cortex and visual cortex for + + + align:start position:0% +auditory cortex and visual cortex for +example + + align:start position:0% + + + + align:start position:0% + +all of its supporting this View + + align:start position:0% + + + + align:start position:0% + +that is so loud + + align:start position:0% + + + + align:start position:0% + +there's a lot of incomplete persolation + + align:start position:0% +there's a lot of incomplete persolation + + + align:start position:0% +there's a lot of incomplete persolation +in fact the some of those those mammals + + align:start position:0% +in fact the some of those those mammals + + + align:start position:0% +in fact the some of those those mammals +you never find complete consolation in + + align:start position:0% +you never find complete consolation in + + + align:start position:0% +you never find complete consolation in +the sensory is and that that is just + + align:start position:0% +the sensory is and that that is just + + + align:start position:0% +the sensory is and that that is just +never taught I don't know why it's not + + align:start position:0% +never taught I don't know why it's not + + + align:start position:0% +never taught I don't know why it's not +taught even heuble and weasel here at + + align:start position:0% +taught even heuble and weasel here at + + + align:start position:0% +taught even heuble and weasel here at +Harvard doing that beautiful work on the + + align:start position:0% +Harvard doing that beautiful work on the + + + align:start position:0% +Harvard doing that beautiful work on the +visual cortex they started with cats + + align:start position:0% +visual cortex they started with cats + + + align:start position:0% +visual cortex they started with cats +they found some auditory inputs into the + + align:start position:0% +they found some auditory inputs into the + + + align:start position:0% +they found some auditory inputs into the +visual cortex of the cad + + align:start position:0% +visual cortex of the cad + + + align:start position:0% +visual cortex of the cad +and you have to look very hard for it in + + align:start position:0% +and you have to look very hard for it in + + + align:start position:0% +and you have to look very hard for it in +their early papers and I asked them + + align:start position:0% +their early papers and I asked them + + + align:start position:0% +their early papers and I asked them +about it one time and they said they + + align:start position:0% +about it one time and they said they + + + align:start position:0% +about it one time and they said they +they Tarson told me yes we did find that + + align:start position:0% +they Tarson told me yes we did find that + + + align:start position:0% +they Tarson told me yes we did find that +and we didn't + + align:start position:0% +and we didn't + + + align:start position:0% +and we didn't +we didn't know what to do with it so we + + align:start position:0% +we didn't know what to do with it so we + + + align:start position:0% +we didn't know what to do with it so we +sort of forgot about it + + align:start position:0% +sort of forgot about it + + + align:start position:0% +sort of forgot about it +they were just working out how the + + align:start position:0% +they were just working out how the + + + align:start position:0% +they were just working out how the +Cascade specification of unit properties + + align:start position:0% +Cascade specification of unit properties + + + align:start position:0% +Cascade specification of unit properties +in the vehicle system + + align:start position:0% +in the vehicle system + + + align:start position:0% +in the vehicle system +because that wasn't on yet so they + + align:start position:0% +because that wasn't on yet so they + + + align:start position:0% +because that wasn't on yet so they +focused on that and so + + align:start position:0% +focused on that and so + + + align:start position:0% +focused on that and so +the auditory input just wasn't important + + align:start position:0% +the auditory input just wasn't important + + + align:start position:0% +the auditory input just wasn't important +to understand the main things the visual + + align:start position:0% +to understand the main things the visual + + + align:start position:0% +to understand the main things the visual +cortex was doing and I'm saying well we + + align:start position:0% +cortex was doing and I'm saying well we + + + align:start position:0% +cortex was doing and I'm saying well we +if we're interested in evolution though + + align:start position:0% +if we're interested in evolution though + + + align:start position:0% +if we're interested in evolution though +we have to pay attention to these kinds + + align:start position:0% +we have to pay attention to these kinds + + + align:start position:0% +we have to pay attention to these kinds +of things + + align:start position:0% + + + + align:start position:0% + +oh the synesthesia okay + + align:start position:0% + + + + align:start position:0% + +there's no yeah there is no evidence for + + align:start position:0% +there's no yeah there is no evidence for + + + align:start position:0% +there's no yeah there is no evidence for +that that I know of + + align:start position:0% +that that I know of + + + align:start position:0% +that that I know of +but now with functional good functional + + align:start position:0% +but now with functional good functional + + + align:start position:0% +but now with functional good functional +Imaging methods it would be possible to + + align:start position:0% +Imaging methods it would be possible to + + + align:start position:0% +Imaging methods it would be possible to +study synesthesia in a way that we + + align:start position:0% +study synesthesia in a way that we + + + align:start position:0% +study synesthesia in a way that we +couldn't before + + align:start position:0% +couldn't before + + + align:start position:0% +couldn't before +you know it's a good question + + align:start position:0% + + + + align:start position:0% + +I will look into that because it's such + + align:start position:0% +I will look into that because it's such + + + align:start position:0% +I will look into that because it's such +an interesting question you know + + align:start position:0% +an interesting question you know + + + align:start position:0% +an interesting question you know +foreign + + align:start position:0% + + + + align:start position:0% + +major differences in the way + + align:start position:0% +major differences in the way + + + align:start position:0% +major differences in the way +in human brain is connected + + align:start position:0% + + + + align:start position:0% + +so this is just what we're talking about + + align:start position:0% +so this is just what we're talking about + + + align:start position:0% +so this is just what we're talking about +uh + + align:start position:0% + + + + align:start position:0% + +and the evidence I talk about this is + + align:start position:0% +and the evidence I talk about this is + + + align:start position:0% +and the evidence I talk about this is +actually from data from hamsters that I + + align:start position:0% +actually from data from hamsters that I + + + align:start position:0% +actually from data from hamsters that I +studied looking at projections from + + align:start position:0% +studied looking at projections from + + + align:start position:0% +studied looking at projections from +inferior colliculus super superficial + + align:start position:0% +inferior colliculus super superficial + + + align:start position:0% +inferior colliculus super superficial +and deep Superior folliculous and from + + align:start position:0% +and deep Superior folliculous and from + + + align:start position:0% +and deep Superior folliculous and from +the pre-tactile area and looking at + + align:start position:0% +the pre-tactile area and looking at + + + align:start position:0% +the pre-tactile area and looking at +where they go and the pattern they form + + align:start position:0% +where they go and the pattern they form + + + align:start position:0% +where they go and the pattern they form +in the valves + + align:start position:0% +in the valves + + + align:start position:0% +in the valves +and uh if you look carefully at this you + + align:start position:0% +and uh if you look carefully at this you + + + align:start position:0% +and uh if you look carefully at this you +see that in the thalamus you have the + + align:start position:0% +see that in the thalamus you have the + + + align:start position:0% +see that in the thalamus you have the +same spatial Arrangement that you have + + align:start position:0% +same spatial Arrangement that you have + + + align:start position:0% +same spatial Arrangement that you have +this here + + align:start position:0% +this here + + + align:start position:0% +this here +the auditory input comes in + + align:start position:0% +the auditory input comes in + + + align:start position:0% +the auditory input comes in +in this more inferior lateral position + + align:start position:0% +in this more inferior lateral position + + + align:start position:0% +in this more inferior lateral position +and that's where it forms its + + align:start position:0% +and that's where it forms its + + + align:start position:0% +and that's where it forms its +connections + + align:start position:0% +connections + + + align:start position:0% +connections +but it's right next to multimodal parts + + align:start position:0% +but it's right next to multimodal parts + + + align:start position:0% +but it's right next to multimodal parts +of the lateral posterior nucleus and + + align:start position:0% +of the lateral posterior nucleus and + + + align:start position:0% +of the lateral posterior nucleus and +then in the more superficial parts of + + align:start position:0% +then in the more superficial parts of + + + align:start position:0% +then in the more superficial parts of +lateral posterior getting inputs + + align:start position:0% +lateral posterior getting inputs + + + align:start position:0% +lateral posterior getting inputs +directly from the spiritual existence + + align:start position:0% +directly from the spiritual existence + + + align:start position:0% +directly from the spiritual existence +visual + + align:start position:0% +visual + + + align:start position:0% +visual +and up in front you have the + + align:start position:0% +and up in front you have the + + + align:start position:0% +and up in front you have the +pre-tactical area and those axons of + + align:start position:0% +pre-tactical area and those axons of + + + align:start position:0% +pre-tactical area and those axons of +course rasterly near the midline and + + align:start position:0% +course rasterly near the midline and + + + align:start position:0% +course rasterly near the midline and +they go right into the roster parts of + + align:start position:0% +they go right into the roster parts of + + + align:start position:0% +they go right into the roster parts of +the lateral nucleus highly neglected + + align:start position:0% +the lateral nucleus highly neglected + + + align:start position:0% +the lateral nucleus highly neglected +that that passage and uh it's only + + align:start position:0% +that that passage and uh it's only + + + align:start position:0% +that that passage and uh it's only +recently that you can find + + align:start position:0% +recently that you can find + + + align:start position:0% +recently that you can find +studies of you know what it might be + + align:start position:0% +studies of you know what it might be + + + align:start position:0% +studies of you know what it might be +doing + + align:start position:0% +doing + + + align:start position:0% +doing +so because I've worked in this area I've + + align:start position:0% +so because I've worked in this area I've + + + align:start position:0% +so because I've worked in this area I've +paid a lot of attention to that + + align:start position:0% + + + + align:start position:0% + +I think when this picture was reproduced + + align:start position:0% +I think when this picture was reproduced + + + align:start position:0% +I think when this picture was reproduced +in the book they put just L because + + align:start position:0% +in the book they put just L because + + + align:start position:0% +in the book they put just L because +it's usually called lateral the lateral + + align:start position:0% +it's usually called lateral the lateral + + + align:start position:0% +it's usually called lateral the lateral +dorsal nucleus a few older Emperors will + + align:start position:0% +dorsal nucleus a few older Emperors will + + + align:start position:0% +dorsal nucleus a few older Emperors will +call it lateral lateralis and interior + + align:start position:0% +call it lateral lateralis and interior + + + align:start position:0% +call it lateral lateralis and interior +okay and then I my interpretation of + + align:start position:0% +okay and then I my interpretation of + + + align:start position:0% +okay and then I my interpretation of +parcellation is that + + align:start position:0% +parcellation is that + + + align:start position:0% +parcellation is that +this is it shows input from the retina + + align:start position:0% +this is it shows input from the retina + + + align:start position:0% +this is it shows input from the retina +here in the dark blue input from + + align:start position:0% +here in the dark blue input from + + + align:start position:0% +here in the dark blue input from +pre-tectin and + + align:start position:0% +pre-tectin and + + + align:start position:0% +pre-tectin and +inferior caliculous and spiritus coming + + align:start position:0% +inferior caliculous and spiritus coming + + + align:start position:0% +inferior caliculous and spiritus coming +into the thalamus and how initially it's + + align:start position:0% +into the thalamus and how initially it's + + + align:start position:0% +into the thalamus and how initially it's +almost certain this big pectin sending + + align:start position:0% +almost certain this big pectin sending + + + align:start position:0% +almost certain this big pectin sending +projections into what initially was a + + align:start position:0% +projections into what initially was a + + + align:start position:0% +projections into what initially was a +pretty small diencephalon they + + align:start position:0% +pretty small diencephalon they + + + align:start position:0% +pretty small diencephalon they +overlapped a lot and if you look at the + + align:start position:0% +overlapped a lot and if you look at the + + + align:start position:0% +overlapped a lot and if you look at the +brain like at the tiger salamander you + + align:start position:0% +brain like at the tiger salamander you + + + align:start position:0% +brain like at the tiger salamander you +find this these kind of widely branched + + align:start position:0% +find this these kind of widely branched + + + align:start position:0% +find this these kind of widely branched +accents and primitive animals and in + + align:start position:0% +accents and primitive animals and in + + + align:start position:0% +accents and primitive animals and in +development you still see a lot of that + + align:start position:0% +development you still see a lot of that + + + align:start position:0% +development you still see a lot of that +but then as they form + + align:start position:0% +but then as they form + + + align:start position:0% +but then as they form +connections + + align:start position:0% +connections + + + align:start position:0% +connections +as the connections increase in density + + align:start position:0% +as the connections increase in density + + + align:start position:0% +as the connections increase in density +they tended to then segregate from the + + align:start position:0% +they tended to then segregate from the + + + align:start position:0% +they tended to then segregate from the +other axons + + align:start position:0% +other axons + + + align:start position:0% +other axons +and that's what I'm showing through + + align:start position:0% +and that's what I'm showing through + + + align:start position:0% +and that's what I'm showing through +these later stages so here they're + + align:start position:0% +these later stages so here they're + + + align:start position:0% +these later stages so here they're +almost completely segregated + + align:start position:0% +almost completely segregated + + + align:start position:0% +almost completely segregated +inferior calculus going down here + + align:start position:0% +inferior calculus going down here + + + align:start position:0% +inferior calculus going down here +the retina going more + + align:start position:0% +the retina going more + + + align:start position:0% +the retina going more +superficially in the thalamus there the + + align:start position:0% +superficially in the thalamus there the + + + align:start position:0% +superficially in the thalamus there the +eventual part + + align:start position:0% + + + + align:start position:0% + +Spirit eclipseless carrying visual input + + align:start position:0% +Spirit eclipseless carrying visual input + + + align:start position:0% +Spirit eclipseless carrying visual input +information that did overlap + + align:start position:0% +information that did overlap + + + align:start position:0% +information that did overlap +with the genesalid body in the genicular + + align:start position:0% +with the genesalid body in the genicular + + + align:start position:0% +with the genesalid body in the genicular +body but then it went to this + + align:start position:0% +body but then it went to this + + + align:start position:0% +body but then it went to this +took over the rights of the lp and the + + align:start position:0% +took over the rights of the lp and the + + + align:start position:0% +took over the rights of the lp and the +pretextual + + align:start position:0% +pretextual + + + align:start position:0% +pretextual +focusing on that + + align:start position:0% +focusing on that + + + align:start position:0% +focusing on that +just specific sections of the lp so you + + align:start position:0% +just specific sections of the lp so you + + + align:start position:0% +just specific sections of the lp so you +end up with this pattern + + align:start position:0% +end up with this pattern + + + align:start position:0% +end up with this pattern +but that process where you get the + + align:start position:0% +but that process where you get the + + + align:start position:0% +but that process where you get the +segregation is called persolation + + align:start position:0% +segregation is called persolation + + + align:start position:0% +segregation is called persolation +experimentally if in development if we + + align:start position:0% +experimentally if in development if we + + + align:start position:0% +experimentally if in development if we +get got the retina to to send + + align:start position:0% +get got the retina to to send + + + align:start position:0% +get got the retina to to send +projections to the wrong side of the + + align:start position:0% +projections to the wrong side of the + + + align:start position:0% +projections to the wrong side of the +tectum here's what they do + + align:start position:0% +tectum here's what they do + + + align:start position:0% +tectum here's what they do +developmentally they grow in and they + + align:start position:0% +developmentally they grow in and they + + + align:start position:0% +developmentally they grow in and they +just overlap with each other they just + + align:start position:0% +just overlap with each other they just + + + align:start position:0% +just overlap with each other they just +and they're trying but then as they + + align:start position:0% +and they're trying but then as they + + + align:start position:0% +and they're trying but then as they +begin to form connections + + align:start position:0% +begin to form connections + + + align:start position:0% +begin to form connections +the connections of one eye and the + + align:start position:0% +the connections of one eye and the + + + align:start position:0% +the connections of one eye and the +connections of the other eye segregate + + align:start position:0% +connections of the other eye segregate + + + align:start position:0% +connections of the other eye segregate +okay as they get denser they tend to + + align:start position:0% +okay as they get denser they tend to + + + align:start position:0% +okay as they get denser they tend to +terminate in the areas closest to where + + align:start position:0% +terminate in the areas closest to where + + + align:start position:0% +terminate in the areas closest to where +they come it came in because that's + + align:start position:0% +they come it came in because that's + + + align:start position:0% +they come it came in because that's +where they form denser connections first + + align:start position:0% +where they form denser connections first + + + align:start position:0% +where they form denser connections first +you see they got there first that's + + align:start position:0% +you see they got there first that's + + + align:start position:0% +you see they got there first that's +where they form the connections first + + align:start position:0% +where they form the connections first + + + align:start position:0% +where they form the connections first +and then they regret they said they pull + + align:start position:0% +and then they regret they said they pull + + + align:start position:0% +and then they regret they said they pull +away from each other + + align:start position:0% +away from each other + + + align:start position:0% +away from each other +literally + + align:start position:0% +literally + + + align:start position:0% +literally +we don't think they they don't + + align:start position:0% +we don't think they they don't + + + align:start position:0% +we don't think they they don't +necessarily degenerate the part that was + + align:start position:0% +necessarily degenerate the part that was + + + align:start position:0% +necessarily degenerate the part that was +but it withdraws + + align:start position:0% +but it withdraws + + + align:start position:0% +but it withdraws +okay + + align:start position:0% +okay + + + align:start position:0% +okay +[Music] + + align:start position:0% + + + + align:start position:0% + +all right uh + + align:start position:0% + + + + align:start position:0% + +so the idea here is that multimodal + + align:start position:0% +so the idea here is that multimodal + + + align:start position:0% +so the idea here is that multimodal +convergence was the Primitive state of + + align:start position:0% +convergence was the Primitive state of + + + align:start position:0% +convergence was the Primitive state of +most or all of the thalamus and the + + align:start position:0% +most or all of the thalamus and the + + + align:start position:0% +most or all of the thalamus and the +incarceration occurred + + align:start position:0% +incarceration occurred + + + align:start position:0% +incarceration occurred +and correlated changes occurred within + + align:start position:0% +and correlated changes occurred within + + + align:start position:0% +and correlated changes occurred within +the within the neocortex + + align:start position:0% +the within the neocortex + + + align:start position:0% +the within the neocortex +and getting reports on a member of the + + align:start position:0% +and getting reports on a member of the + + + align:start position:0% +and getting reports on a member of the +family that's in the hospital + + align:start position:0% + + + + align:start position:0% + +wait + + align:start position:0% +wait + + + align:start position:0% +wait +if you look at that + + align:start position:0% + + + + align:start position:0% + +all right so can you look across widely + + align:start position:0% +all right so can you look across widely + + + align:start position:0% +all right so can you look across widely +different animals like here's the + + align:start position:0% +different animals like here's the + + + align:start position:0% +different animals like here's the +and on the outs this is animals like the + + align:start position:0% +and on the outs this is animals like the + + + align:start position:0% +and on the outs this is animals like the +the salamander or the the Frog you know + + align:start position:0% +the salamander or the the Frog you know + + + align:start position:0% +the salamander or the the Frog you know +they have fewer thalamic areas when you + + align:start position:0% +they have fewer thalamic areas when you + + + align:start position:0% +they have fewer thalamic areas when you +go up to reptiles there's more birds + + align:start position:0% +go up to reptiles there's more birds + + + align:start position:0% +go up to reptiles there's more birds +even more and mammals than most + + align:start position:0% +even more and mammals than most + + + align:start position:0% +even more and mammals than most +if you look in the human compared with + + align:start position:0% +if you look in the human compared with + + + align:start position:0% +if you look in the human compared with +uh + + align:start position:0% +uh + + + align:start position:0% +uh +other + + align:start position:0% +other + + + align:start position:0% +other +primates you'll find + + align:start position:0% +primates you'll find + + + align:start position:0% +primates you'll find +the same Aries but you can subdivide the + + align:start position:0% +the same Aries but you can subdivide the + + + align:start position:0% +the same Aries but you can subdivide the +areas more it's like the brain with + + align:start position:0% +areas more it's like the brain with + + + align:start position:0% +areas more it's like the brain with +Evolution becomes more specialized + + align:start position:0% +Evolution becomes more specialized + + + align:start position:0% +Evolution becomes more specialized +there's more persolation + + align:start position:0% +there's more persolation + + + align:start position:0% +there's more persolation +than there is earlier and that's what + + align:start position:0% +than there is earlier and that's what + + + align:start position:0% +than there is earlier and that's what +this comparative data support this is + + align:start position:0% +this comparative data support this is + + + align:start position:0% +this comparative data support this is +just a concept + + align:start position:0% + + + + align:start position:0% + +based on one that street or published + + align:start position:0% +based on one that street or published + + + align:start position:0% +based on one that street or published +and he after reviewing a lot of this + + align:start position:0% +and he after reviewing a lot of this + + + align:start position:0% +and he after reviewing a lot of this +work + + align:start position:0% + + + + align:start position:0% + +and then I talk about these three + + align:start position:0% +and then I talk about these three + + + align:start position:0% +and then I talk about these three +systems separately these are all things + + align:start position:0% +systems separately these are all things + + + align:start position:0% +systems separately these are all things +that we did talk about + + align:start position:0% +that we did talk about + + + align:start position:0% +that we did talk about +when we talked about these systems is + + align:start position:0% +when we talked about these systems is + + + align:start position:0% +when we talked about these systems is +just to remind you + + align:start position:0% + + + + align:start position:0% + +and then I talked about that segregation + + align:start position:0% +and then I talked about that segregation + + + align:start position:0% +and then I talked about that segregation +within this meta sensory system that led + + align:start position:0% +within this meta sensory system that led + + + align:start position:0% +within this meta sensory system that led +to the revolution of the motor cortex + + align:start position:0% +to the revolution of the motor cortex + + + align:start position:0% +to the revolution of the motor cortex +and this is the picture that I had this + + align:start position:0% +and this is the picture that I had this + + + align:start position:0% +and this is the picture that I had this +was from chapter 15. and it shows how + + align:start position:0% +was from chapter 15. and it shows how + + + align:start position:0% +was from chapter 15. and it shows how +you can Define + + align:start position:0% +you can Define + + + align:start position:0% +you can Define +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +somatosensory + + align:start position:0% +somatosensory + + + align:start position:0% +somatosensory +cortex you can Define it in terms of + + align:start position:0% +cortex you can Define it in terms of + + + align:start position:0% +cortex you can Define it in terms of +projections the part that gets input + + align:start position:0% +projections the part that gets input + + + align:start position:0% +projections the part that gets input +from the posterior nucleus + + align:start position:0% +from the posterior nucleus + + + align:start position:0% +from the posterior nucleus +because that's where this sensory come + + align:start position:0% +because that's where this sensory come + + + align:start position:0% +because that's where this sensory come +input comes in from the spinal cord in + + align:start position:0% +input comes in from the spinal cord in + + + align:start position:0% +input comes in from the spinal cord in +the trigeminal system and then anterior + + align:start position:0% +the trigeminal system and then anterior + + + align:start position:0% +the trigeminal system and then anterior +to that the ventral lateral nucleus + + align:start position:0% +to that the ventral lateral nucleus + + + align:start position:0% +to that the ventral lateral nucleus +projects + + align:start position:0% +projects + + + align:start position:0% +projects +what we call them or cortex the primary + + align:start position:0% +what we call them or cortex the primary + + + align:start position:0% +what we call them or cortex the primary +motor cortex the VA anterior just goes + + align:start position:0% +motor cortex the VA anterior just goes + + + align:start position:0% +motor cortex the VA anterior just goes +even more anterior premolar cortex + + align:start position:0% +even more anterior premolar cortex + + + align:start position:0% +even more anterior premolar cortex +and it shows how these the projections + + align:start position:0% +and it shows how these the projections + + + align:start position:0% +and it shows how these the projections +of those two nuclei are completely + + align:start position:0% +of those two nuclei are completely + + + align:start position:0% +of those two nuclei are completely +overlapping in The Virginian across so + + align:start position:0% +overlapping in The Virginian across so + + + align:start position:0% +overlapping in The Virginian across so +if you record from it physiologically + + align:start position:0% +if you record from it physiologically + + + align:start position:0% +if you record from it physiologically +you can't you can't separate them + + align:start position:0% +you can't you can't separate them + + + align:start position:0% +you can't you can't separate them +you study the projections again + + align:start position:0% +you study the projections again + + + align:start position:0% +you study the projections again +and then in this is not the opossum it's + + align:start position:0% +and then in this is not the opossum it's + + + align:start position:0% +and then in this is not the opossum it's +the brushed head possum it's a different + + align:start position:0% +the brushed head possum it's a different + + + align:start position:0% +the brushed head possum it's a different +animal and you find an area that doesn't + + align:start position:0% +animal and you find an area that doesn't + + + align:start position:0% +animal and you find an area that doesn't +overlap for each of these nuclei but + + align:start position:0% +overlap for each of these nuclei but + + + align:start position:0% +overlap for each of these nuclei but +then there's a fairly large area where + + align:start position:0% +then there's a fairly large area where + + + align:start position:0% +then there's a fairly large area where +they overlap if you look at a rat + + align:start position:0% +they overlap if you look at a rat + + + align:start position:0% +they overlap if you look at a rat +there's just an area of the hind limb + + align:start position:0% +there's just an area of the hind limb + + + align:start position:0% +there's just an area of the hind limb +representation where there has not been + + align:start position:0% +representation where there has not been + + + align:start position:0% +representation where there has not been +a complete parcelation + + align:start position:0% +a complete parcelation + + + align:start position:0% +a complete parcelation +but otherwise it's pretty good if you + + align:start position:0% +but otherwise it's pretty good if you + + + align:start position:0% +but otherwise it's pretty good if you +look at a primate + + align:start position:0% +look at a primate + + + align:start position:0% +look at a primate +dialogue + + align:start position:0% + + + + align:start position:0% + +complete segregation that's true all the + + align:start position:0% +complete segregation that's true all the + + + align:start position:0% +complete segregation that's true all the +larger climates in fact I think all of + + align:start position:0% +larger climates in fact I think all of + + + align:start position:0% +larger climates in fact I think all of +the primates that I know about are like + + align:start position:0% +the primates that I know about are like + + + align:start position:0% +the primates that I know about are like +that + + align:start position:0% + + + + align:start position:0% + +so the evidence is pretty good for this + + align:start position:0% +so the evidence is pretty good for this + + + align:start position:0% +so the evidence is pretty good for this +kind of + + align:start position:0% +kind of + + + align:start position:0% +kind of +parcellation in this meta sensory system + + align:start position:0% +parcellation in this meta sensory system + + + align:start position:0% +parcellation in this meta sensory system +and how the motor cortex signals out of + + align:start position:0% +and how the motor cortex signals out of + + + align:start position:0% +and how the motor cortex signals out of +it okay whereas for the visual system + + align:start position:0% +it okay whereas for the visual system + + + align:start position:0% +it okay whereas for the visual system +people have looked at widely different + + align:start position:0% +people have looked at widely different + + + align:start position:0% +people have looked at widely different +animals including marsupials you always + + align:start position:0% +animals including marsupials you always + + + align:start position:0% +animals including marsupials you always +see a V1 and a V2 + + align:start position:0% + + + + align:start position:0% + +and in most of them you see a fern area + + align:start position:0% +and in most of them you see a fern area + + + align:start position:0% +and in most of them you see a fern area +that's always there and Mary we call him + + align:start position:0% +that's always there and Mary we call him + + + align:start position:0% +that's always there and Mary we call him +tea and the monkeys + + align:start position:0% + + + + align:start position:0% + +and then you'll see varying numbers of + + align:start position:0% +and then you'll see varying numbers of + + + align:start position:0% +and then you'll see varying numbers of +there + + align:start position:0% +there + + + align:start position:0% +there +additional visual areas and some there + + align:start position:0% +additional visual areas and some there + + + align:start position:0% +additional visual areas and some there +are not many at all not much cortex + + align:start position:0% +are not many at all not much cortex + + + align:start position:0% +are not many at all not much cortex +but in the large premise in humans + + align:start position:0% +but in the large premise in humans + + + align:start position:0% +but in the large premise in humans +there's a very large + + align:start position:0% +there's a very large + + + align:start position:0% +there's a very large +so these are the methods of expansion + + align:start position:0% +so these are the methods of expansion + + + align:start position:0% +so these are the methods of expansion +that you talk about these are pictures + + align:start position:0% +that you talk about these are pictures + + + align:start position:0% +that you talk about these are pictures +of that + + align:start position:0% +of that + + + align:start position:0% +of that +the + + align:start position:0% +the + + + align:start position:0% +the +primates and here you see in + + align:start position:0% +primates and here you see in + + + align:start position:0% +primates and here you see in +the gray color here + + align:start position:0% + + + + align:start position:0% + +you see what Muslim calls the + + align:start position:0% +you see what Muslim calls the + + + align:start position:0% +you see what Muslim calls the +heteromotive here it's the multimodal + + align:start position:0% +heteromotive here it's the multimodal + + + align:start position:0% +heteromotive here it's the multimodal +areas + + align:start position:0% +areas + + + align:start position:0% +areas +and it's typical + + align:start position:0% +and it's typical + + + align:start position:0% +and it's typical +picture + + align:start position:0% +picture + + + align:start position:0% +picture +rat and Hedgehog especially hedgehogs + + align:start position:0% +rat and Hedgehog especially hedgehogs + + + align:start position:0% +rat and Hedgehog especially hedgehogs +see how they picture no multimodal areas + + align:start position:0% + + + + align:start position:0% + +I find it'll be interesting to see how + + align:start position:0% +I find it'll be interesting to see how + + + align:start position:0% +I find it'll be interesting to see how +my colleagues that have published these + + align:start position:0% +my colleagues that have published these + + + align:start position:0% +my colleagues that have published these +kinds of pictures for a long time will + + align:start position:0% +kinds of pictures for a long time will + + + align:start position:0% +kinds of pictures for a long time will +react because I've looked really + + align:start position:0% +react because I've looked really + + + align:start position:0% +react because I've looked really +carefully at that literature and that is + + align:start position:0% +carefully at that literature and that is + + + align:start position:0% +carefully at that literature and that is +not what you find + + align:start position:0% +not what you find + + + align:start position:0% +not what you find +there's a lot of multimodal Cortex and + + align:start position:0% +there's a lot of multimodal Cortex and + + + align:start position:0% +there's a lot of multimodal Cortex and +this is + + align:start position:0% +this is + + + align:start position:0% +this is +so I have this slide multimodal regions + + align:start position:0% +so I have this slide multimodal regions + + + align:start position:0% +so I have this slide multimodal regions +do exist in between the major sensory + + align:start position:0% +do exist in between the major sensory + + + align:start position:0% +do exist in between the major sensory +areas and Hedgehog hamster gold + + align:start position:0% +areas and Hedgehog hamster gold + + + align:start position:0% +areas and Hedgehog hamster gold +it's been thus studied in the cold + + align:start position:0% +it's been thus studied in the cold + + + align:start position:0% +it's been thus studied in the cold +and unimodal and multimodal + + align:start position:0% +and unimodal and multimodal + + + align:start position:0% +and unimodal and multimodal +dissociationaries are not so + + align:start position:0% +dissociationaries are not so + + + align:start position:0% +dissociationaries are not so +distinguishable + + align:start position:0% + + + + align:start position:0% + +because they're all multimodal at least + + align:start position:0% +because they're all multimodal at least + + + align:start position:0% +because they're all multimodal at least +two modalities will go into their series + + align:start position:0% +two modalities will go into their series + + + align:start position:0% +two modalities will go into their series +they might be dominated by one since but + + align:start position:0% +they might be dominated by one since but + + + align:start position:0% +they might be dominated by one since but +they're not really unimodal association + + align:start position:0% +they're not really unimodal association + + + align:start position:0% +they're not really unimodal association +race + + align:start position:0% + + + + align:start position:0% + +and then I talk about some multimodal + + align:start position:0% +and then I talk about some multimodal + + + align:start position:0% +and then I talk about some multimodal +inputs even in the primary sensory areas + + align:start position:0% + + + + align:start position:0% + +so in that Indie just indicates that + + align:start position:0% +so in that Indie just indicates that + + + align:start position:0% +so in that Indie just indicates that +this parcellation is complete + + align:start position:0% +this parcellation is complete + + + align:start position:0% +this parcellation is complete +maybe in in the large primates in humans + + align:start position:0% +maybe in in the large primates in humans + + + align:start position:0% +maybe in in the large primates in humans +it's about as complete as it can be + + align:start position:0% +it's about as complete as it can be + + + align:start position:0% +it's about as complete as it can be +but not in many animals + + align:start position:0% +but not in many animals + + + align:start position:0% +but not in many animals +so it's a neglected fact that gives + + align:start position:0% +so it's a neglected fact that gives + + + align:start position:0% +so it's a neglected fact that gives +clues about evolution + + align:start position:0% +clues about evolution + + + align:start position:0% +clues about evolution +because of that I paid a lot of + + align:start position:0% +because of that I paid a lot of + + + align:start position:0% +because of that I paid a lot of +attention to it and then I have a little + + align:start position:0% +attention to it and then I have a little + + + align:start position:0% +attention to it and then I have a little +bit about axon trajectories that you + + align:start position:0% +bit about axon trajectories that you + + + align:start position:0% +bit about axon trajectories that you +should realize + + align:start position:0% +should realize + + + align:start position:0% +should realize +that in this is for reptilian cortex but + + align:start position:0% +that in this is for reptilian cortex but + + + align:start position:0% +that in this is for reptilian cortex but +you see the same thing for + + align:start position:0% +you see the same thing for + + + align:start position:0% +you see the same thing for +amphibians + + align:start position:0% +amphibians + + + align:start position:0% +amphibians +and Fishes were in the cortex the axons + + align:start position:0% +and Fishes were in the cortex the axons + + + align:start position:0% +and Fishes were in the cortex the axons +don't come in from below like in this + + align:start position:0% +don't come in from below like in this + + + align:start position:0% +don't come in from below like in this +picture you see here for uh the Hedgehog + + align:start position:0% +picture you see here for uh the Hedgehog + + + align:start position:0% +picture you see here for uh the Hedgehog +the mammal they come in through the + + align:start position:0% +the mammal they come in through the + + + align:start position:0% +the mammal they come in through the +white matter then they go up and + + align:start position:0% +white matter then they go up and + + + align:start position:0% +white matter then they go up and +terminate in the various layers + + align:start position:0% +terminate in the various layers + + + align:start position:0% +terminate in the various layers +including layer one there whereas in + + align:start position:0% +including layer one there whereas in + + + align:start position:0% +including layer one there whereas in +the reptiles and turtles and the + + align:start position:0% +the reptiles and turtles and the + + + align:start position:0% +the reptiles and turtles and the +salamander and other + + align:start position:0% +salamander and other + + + align:start position:0% +salamander and other +amphibians they come in + + align:start position:0% +amphibians they come in + + + align:start position:0% +amphibians they come in +like this they don't come in through a + + align:start position:0% +like this they don't come in through a + + + align:start position:0% +like this they don't come in through a +white matter they travel eventually so + + align:start position:0% +white matter they travel eventually so + + + align:start position:0% +white matter they travel eventually so +if you look + + align:start position:0% +if you look + + + align:start position:0% +if you look +this is the way that this + + align:start position:0% + + + + align:start position:0% + +pictured an almond he used the picture + + align:start position:0% +pictured an almond he used the picture + + + align:start position:0% +pictured an almond he used the picture +here of Pedro Ramon Pedro Pedro romoni + + align:start position:0% +here of Pedro Ramon Pedro Pedro romoni + + + align:start position:0% +here of Pedro Ramon Pedro Pedro romoni +kahal Ramona kahal's brother Santiago + + align:start position:0% +kahal Ramona kahal's brother Santiago + + + align:start position:0% +kahal Ramona kahal's brother Santiago +romanica house brother sorry and this is + + align:start position:0% +romanica house brother sorry and this is + + + align:start position:0% +romanica house brother sorry and this is +from the American + + align:start position:0% +from the American + + + align:start position:0% +from the American +CJ Harry + + align:start position:0% +CJ Harry + + + align:start position:0% +CJ Harry +where he shows a similar level where you + + align:start position:0% +where he shows a similar level where you + + + align:start position:0% +where he shows a similar level where you +see this + + align:start position:0% +see this + + + align:start position:0% +see this +beautifully thick medial pallium + + align:start position:0% +beautifully thick medial pallium + + + align:start position:0% +beautifully thick medial pallium +with this cortex next to it + + align:start position:0% +with this cortex next to it + + + align:start position:0% +with this cortex next to it +because and + + align:start position:0% +because and + + + align:start position:0% +because and +it's a multimodal area + + align:start position:0% +it's a multimodal area + + + align:start position:0% +it's a multimodal area +a dorsal cortex and most animals it's + + align:start position:0% +a dorsal cortex and most animals it's + + + align:start position:0% +a dorsal cortex and most animals it's +called dorsa pallium cortex + + align:start position:0% +called dorsa pallium cortex + + + align:start position:0% +called dorsa pallium cortex +and IT projects heavily into the + + align:start position:0% +and IT projects heavily into the + + + align:start position:0% +and IT projects heavily into the +mediality but it gets multimodal input + + align:start position:0% +mediality but it gets multimodal input + + + align:start position:0% +mediality but it gets multimodal input +from balance but to see how the axons + + align:start position:0% +from balance but to see how the axons + + + align:start position:0% +from balance but to see how the axons +travel here they come out of the letter + + align:start position:0% +travel here they come out of the letter + + + align:start position:0% +travel here they come out of the letter +Corbin Runner when they travel they + + align:start position:0% +Corbin Runner when they travel they + + + align:start position:0% +Corbin Runner when they travel they +don't travel through a white matter at + + align:start position:0% +don't travel through a white matter at + + + align:start position:0% +don't travel through a white matter at +the base not to announce okay so then I + + align:start position:0% +the base not to announce okay so then I + + + align:start position:0% +the base not to announce okay so then I +point out that in the hamster + + align:start position:0% +point out that in the hamster + + + align:start position:0% +point out that in the hamster +and this is true for Hedgehog two there + + align:start position:0% +and this is true for Hedgehog two there + + + align:start position:0% +and this is true for Hedgehog two there +are some neurons in lateral films + + align:start position:0% +are some neurons in lateral films + + + align:start position:0% +are some neurons in lateral films +some of the data indicates they might + + align:start position:0% +some of the data indicates they might + + + align:start position:0% +some of the data indicates they might +all be in the posterior nuclear group + + align:start position:0% +all be in the posterior nuclear group + + + align:start position:0% +all be in the posterior nuclear group +but they're in the lateral Thalamus and + + align:start position:0% +but they're in the lateral Thalamus and + + + align:start position:0% +but they're in the lateral Thalamus and +they have a they have a trajectory + + align:start position:0% +they have a they have a trajectory + + + align:start position:0% +they have a they have a trajectory +that's more like this primitive animals + + align:start position:0% +that's more like this primitive animals + + + align:start position:0% +that's more like this primitive animals +so here's I call it the type 1 axon + + align:start position:0% +so here's I call it the type 1 axon + + + align:start position:0% +so here's I call it the type 1 axon +coming in like from geniculid body and + + align:start position:0% +coming in like from geniculid body and + + + align:start position:0% +coming in like from geniculid body and +arborizing primarily in layer one and + + align:start position:0% +arborizing primarily in layer one and + + + align:start position:0% +arborizing primarily in layer one and +four but they have some branches in the + + align:start position:0% +four but they have some branches in the + + + align:start position:0% +four but they have some branches in the +other layers as well but then you have + + align:start position:0% +other layers as well but then you have + + + align:start position:0% +other layers as well but then you have +this other type + + align:start position:0% +this other type + + + align:start position:0% +this other type +the travel long distances and terminate + + align:start position:0% +the travel long distances and terminate + + + align:start position:0% +the travel long distances and terminate +it's like they ignore the boundaries + + align:start position:0% +it's like they ignore the boundaries + + + align:start position:0% +it's like they ignore the boundaries +between + + align:start position:0% +between + + + align:start position:0% +between +Century between cortical areas + + align:start position:0% +Century between cortical areas + + + align:start position:0% +Century between cortical areas +they go + + align:start position:0% +they go + + + align:start position:0% +they go +even the primary visual cortex + + align:start position:0% +even the primary visual cortex + + + align:start position:0% +even the primary visual cortex +apparently carrying multimodal input + + align:start position:0% +apparently carrying multimodal input + + + align:start position:0% +apparently carrying multimodal input +it's an anatomical + + align:start position:0% +it's an anatomical + + + align:start position:0% +it's an anatomical +now uh + + align:start position:0% +now uh + + + align:start position:0% +now uh +it's an odd fact in neuroanatomy that + + align:start position:0% +it's an odd fact in neuroanatomy that + + + align:start position:0% +it's an odd fact in neuroanatomy that +subjections exist and they've not been + + align:start position:0% +subjections exist and they've not been + + + align:start position:0% +subjections exist and they've not been +studied very well at all + + align:start position:0% +studied very well at all + + + align:start position:0% +studied very well at all +okay but they can account for some of + + align:start position:0% +okay but they can account for some of + + + align:start position:0% +okay but they can account for some of +the physiological results that we've + + align:start position:0% +the physiological results that we've + + + align:start position:0% +the physiological results that we've +been talking about + + align:start position:0% + + + + align:start position:0% + +so I want to talk more specifically now + + align:start position:0% +so I want to talk more specifically now + + + align:start position:0% +so I want to talk more specifically now +about + + align:start position:0% +about + + + align:start position:0% +about +this is now a step from chapter 33. + + align:start position:0% +this is now a step from chapter 33. + + + align:start position:0% +this is now a step from chapter 33. +which we'll talk about next time as well + + align:start position:0% + + + + align:start position:0% + +we'll try to finish chapter 33 next time + + align:start position:0% +we'll try to finish chapter 33 next time + + + align:start position:0% +we'll try to finish chapter 33 next time +and maybe at least get started + + align:start position:0% + + + + align:start position:0% + +chapter in the book + + align:start position:0% +chapter in the book + + + align:start position:0% +chapter in the book +so + + align:start position:0% +so + + + align:start position:0% +so +I want to say more about cell types and + + align:start position:0% +I want to say more about cell types and + + + align:start position:0% +I want to say more about cell types and +their connections + + align:start position:0% + + + + align:start position:0% + +different regions how we name them + + align:start position:0% +different regions how we name them + + + align:start position:0% +different regions how we name them +there's different ways to talk about + + align:start position:0% +there's different ways to talk about + + + align:start position:0% +there's different ways to talk about +different reasons and then the major + + align:start position:0% +different reasons and then the major + + + align:start position:0% +different reasons and then the major +fiber Roots which we brought up before I + + align:start position:0% +fiber Roots which we brought up before I + + + align:start position:0% +fiber Roots which we brought up before I +want to review them + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +you you should be able to contrast some + + align:start position:0% +you you should be able to contrast some + + + align:start position:0% +you you should be able to contrast some +of the major neuronal cell types what + + align:start position:0% +of the major neuronal cell types what + + + align:start position:0% +of the major neuronal cell types what +are the two main cell types that you can + + align:start position:0% +are the two main cell types that you can + + + align:start position:0% +are the two main cell types that you can +think of if you just think of structure + + align:start position:0% +think of if you just think of structure + + + align:start position:0% +think of if you just think of structure +and talking about neocortex + + align:start position:0% +and talking about neocortex + + + align:start position:0% +and talking about neocortex +when now they talked about these he just + + align:start position:0% +when now they talked about these he just + + + align:start position:0% +when now they talked about these he just +mainly talked about these two cell types + + align:start position:0% +mainly talked about these two cell types + + + align:start position:0% +mainly talked about these two cell types +the dominant cell type + + align:start position:0% +the dominant cell type + + + align:start position:0% +the dominant cell type +parameter cells + + align:start position:0% +parameter cells + + + align:start position:0% +parameter cells +the apical dendrite going right up + + align:start position:0% +the apical dendrite going right up + + + align:start position:0% +the apical dendrite going right up +towards the surface and arborizing okay + + align:start position:0% +towards the surface and arborizing okay + + + align:start position:0% +towards the surface and arborizing okay +and the other type you can lump them all + + align:start position:0% +and the other type you can lump them all + + + align:start position:0% +and the other type you can lump them all +together and call them skelets there are + + align:start position:0% +together and call them skelets there are + + + align:start position:0% +together and call them skelets there are +other shapes + + align:start position:0% +other shapes + + + align:start position:0% +other shapes +a few Supreme shapes for example + + align:start position:0% +a few Supreme shapes for example + + + align:start position:0% +a few Supreme shapes for example +sort of a bipolar looking neuron + + align:start position:0% +sort of a bipolar looking neuron + + + align:start position:0% +sort of a bipolar looking neuron +but there's other ways to classify them + + align:start position:0% + + + + align:start position:0% + +you can use neurotransmitters you can + + align:start position:0% +you can use neurotransmitters you can + + + align:start position:0% +you can use neurotransmitters you can +use whether they're spiny or non-spining + + align:start position:0% +use whether they're spiny or non-spining + + + align:start position:0% +use whether they're spiny or non-spining +uh + + align:start position:0% +uh + + + align:start position:0% +uh +whether they're excitatory or inhibitory + + align:start position:0% +whether they're excitatory or inhibitory + + + align:start position:0% +whether they're excitatory or inhibitory +so + + align:start position:0% + + + + align:start position:0% + +so the criteria vary and the nicest + + align:start position:0% +so the criteria vary and the nicest + + + align:start position:0% +so the criteria vary and the nicest +classification I've seen is in this + + align:start position:0% +classification I've seen is in this + + + align:start position:0% +classification I've seen is in this +picture which I put in the book + + align:start position:0% +picture which I put in the book + + + align:start position:0% +picture which I put in the book +in which they separate these groups + + align:start position:0% +in which they separate these groups + + + align:start position:0% +in which they separate these groups +according to the spiny excitatory + + align:start position:0% +according to the spiny excitatory + + + align:start position:0% +according to the spiny excitatory +neurons of using glutamate as a + + align:start position:0% +neurons of using glutamate as a + + + align:start position:0% +neurons of using glutamate as a +transmitter the non-spiny inhibitory or + + align:start position:0% +transmitter the non-spiny inhibitory or + + + align:start position:0% +transmitter the non-spiny inhibitory or +gabaergic or interneurons + + align:start position:0% +gabaergic or interneurons + + + align:start position:0% +gabaergic or interneurons +and notice that these are most all + + align:start position:0% +and notice that these are most all + + + align:start position:0% +and notice that these are most all +stellate in shape a few of them might + + align:start position:0% +stellate in shape a few of them might + + + align:start position:0% +stellate in shape a few of them might +have a few subconscious and mostly the + + align:start position:0% +have a few subconscious and mostly the + + + align:start position:0% +have a few subconscious and mostly the +star-shaped and cells that don't have an + + align:start position:0% +star-shaped and cells that don't have an + + + align:start position:0% +star-shaped and cells that don't have an +apical dendrite here are the pyramidal + + align:start position:0% +apical dendrite here are the pyramidal + + + align:start position:0% +apical dendrite here are the pyramidal +cells + + align:start position:0% +cells + + + align:start position:0% +cells +with this apical dandruff and this + + align:start position:0% + + + + align:start position:0% + +you see here + + align:start position:0% +you see here + + + align:start position:0% +you see here +this is one in layer five it's a big + + align:start position:0% +this is one in layer five it's a big + + + align:start position:0% +this is one in layer five it's a big +pyramidal cell + + align:start position:0% +pyramidal cell + + + align:start position:0% +pyramidal cell +the apical dendrite goes right up and + + align:start position:0% +the apical dendrite goes right up and + + + align:start position:0% +the apical dendrite goes right up and +arborizes in layer one + + align:start position:0% +arborizes in layer one + + + align:start position:0% +arborizes in layer one +and usually these pictures lack a lot of + + align:start position:0% +and usually these pictures lack a lot of + + + align:start position:0% +and usually these pictures lack a lot of +the processes that are really there + + align:start position:0% +the processes that are really there + + + align:start position:0% +the processes that are really there +they're pretty complex and it shows an + + align:start position:0% +they're pretty complex and it shows an + + + align:start position:0% +they're pretty complex and it shows an +enlargement here + + align:start position:0% +enlargement here + + + align:start position:0% +enlargement here +you look at higher magnification of a + + align:start position:0% +you look at higher magnification of a + + + align:start position:0% +you look at higher magnification of a +Golgi stain or a cell that's been filled + + align:start position:0% +Golgi stain or a cell that's been filled + + + align:start position:0% +Golgi stain or a cell that's been filled +with hrp or something like that you see + + align:start position:0% +with hrp or something like that you see + + + align:start position:0% +with hrp or something like that you see +the little spines they can take so + + align:start position:0% +the little spines they can take so + + + align:start position:0% +the little spines they can take so +that's + + align:start position:0% +that's + + + align:start position:0% +that's +the spines are + + align:start position:0% +the spines are + + + align:start position:0% +the spines are +sites in many of this many of the + + align:start position:0% +sites in many of this many of the + + + align:start position:0% +sites in many of this many of the +synapses are formed in response + + align:start position:0% + + + + align:start position:0% + +and then it shows where they go + + align:start position:0% +and then it shows where they go + + + align:start position:0% +and then it shows where they go +like these big cells in layer five go to + + align:start position:0% +like these big cells in layer five go to + + + align:start position:0% +like these big cells in layer five go to +the + + align:start position:0% +the + + + align:start position:0% +the +spinal cord brain stem Thalamus triatum + + align:start position:0% +spinal cord brain stem Thalamus triatum + + + align:start position:0% +spinal cord brain stem Thalamus triatum +and other areas of Cortex + + align:start position:0% +and other areas of Cortex + + + align:start position:0% +and other areas of Cortex +okay + + align:start position:0% +okay + + + align:start position:0% +okay +the pyramidal cells in layer three and + + align:start position:0% +the pyramidal cells in layer three and + + + align:start position:0% +the pyramidal cells in layer three and +Layer Two are much smaller but they're + + align:start position:0% +Layer Two are much smaller but they're + + + align:start position:0% +Layer Two are much smaller but they're +still pyramidal in shape they go They're + + align:start position:0% +still pyramidal in shape they go They're + + + align:start position:0% +still pyramidal in shape they go They're +transported so there + + align:start position:0% +transported so there + + + align:start position:0% +transported so there +are Association cells of the cortex + + align:start position:0% +are Association cells of the cortex + + + align:start position:0% +are Association cells of the cortex +in our propio cortical cells a term + + align:start position:0% +in our propio cortical cells a term + + + align:start position:0% +in our propio cortical cells a term +that's not usually used but it's an + + align:start position:0% +that's not usually used but it's an + + + align:start position:0% +that's not usually used but it's an +appropriate term and the only excitatory + + align:start position:0% +appropriate term and the only excitatory + + + align:start position:0% +appropriate term and the only excitatory +cell here that's not parameter in shape + + align:start position:0% +cell here that's not parameter in shape + + + align:start position:0% +cell here that's not parameter in shape +is a distillate cell we haven't called + + align:start position:0% +is a distillate cell we haven't called + + + align:start position:0% +is a distillate cell we haven't called +them granulson in layer four they get a + + align:start position:0% +them granulson in layer four they get a + + + align:start position:0% +them granulson in layer four they get a +lot of them a lot a lot of input from + + align:start position:0% +lot of them a lot a lot of input from + + + align:start position:0% +lot of them a lot a lot of input from +the thalamus comes in there and the + + align:start position:0% +the thalamus comes in there and the + + + align:start position:0% +the thalamus comes in there and the +axons simply + + align:start position:0% +axons simply + + + align:start position:0% +axons simply +terminates within the same column + + align:start position:0% +terminates within the same column + + + align:start position:0% +terminates within the same column +carries that information right up to the + + align:start position:0% +carries that information right up to the + + + align:start position:0% +carries that information right up to the +superficial layers which we often call + + align:start position:0% +superficial layers which we often call + + + align:start position:0% +superficial layers which we often call +Association layers layers two and three + + align:start position:0% +Association layers layers two and three + + + align:start position:0% +Association layers layers two and three +because they contain these neurons + + align:start position:0% +because they contain these neurons + + + align:start position:0% +because they contain these neurons +they're getting input + + align:start position:0% +they're getting input + + + align:start position:0% +they're getting input +from these stellates and therefore and + + align:start position:0% +from these stellates and therefore and + + + align:start position:0% +from these stellates and therefore and +they're projecting + + align:start position:0% +they're projecting + + + align:start position:0% +they're projecting +to other areas of Cortex + + align:start position:0% +to other areas of Cortex + + + align:start position:0% +to other areas of Cortex +now they do get other inputs they get + + align:start position:0% +now they do get other inputs they get + + + align:start position:0% +now they do get other inputs they get +some direct information problems too + + align:start position:0% +some direct information problems too + + + align:start position:0% +some direct information problems too +because the thalamus context those + + align:start position:0% +because the thalamus context those + + + align:start position:0% +because the thalamus context those +branches of the + + align:start position:0% +branches of the + + + align:start position:0% +branches of the +of the parameters + + align:start position:0% +of the parameters + + + align:start position:0% +of the parameters +and then you'll see here for the + + align:start position:0% +and then you'll see here for the + + + align:start position:0% +and then you'll see here for the +non-spiny inhibitory inner neurons how + + align:start position:0% +non-spiny inhibitory inner neurons how + + + align:start position:0% +non-spiny inhibitory inner neurons how +many different shapes and look at the + + align:start position:0% +many different shapes and look at the + + + align:start position:0% +many different shapes and look at the +the way the axons + + align:start position:0% +the way the axons + + + align:start position:0% +the way the axons +form + + align:start position:0% +form + + + align:start position:0% +form +you know you see + + align:start position:0% + + + + align:start position:0% + +cells like + + align:start position:0% +cells like + + + align:start position:0% +cells like +like this that have an axon that + + align:start position:0% +like this that have an axon that + + + align:start position:0% +like this that have an axon that +distributes + + align:start position:0% +distributes + + + align:start position:0% +distributes +all the nearby columns here's one that + + align:start position:0% +all the nearby columns here's one that + + + align:start position:0% +all the nearby columns here's one that +is + + align:start position:0% +is + + + align:start position:0% +is +all the the axon distributes up and down + + align:start position:0% +all the the axon distributes up and down + + + align:start position:0% +all the the axon distributes up and down +the same column + + align:start position:0% +the same column + + + align:start position:0% +the same column +okay + + align:start position:0% +okay + + + align:start position:0% +okay +but they've all got local accents some + + align:start position:0% +but they've all got local accents some + + + align:start position:0% +but they've all got local accents some +of them covering a number of columns + + align:start position:0% +of them covering a number of columns + + + align:start position:0% +of them covering a number of columns +some of them some of them covering only + + align:start position:0% +some of them some of them covering only + + + align:start position:0% +some of them some of them covering only +one column + + align:start position:0% +one column + + + align:start position:0% +one column +but so two major divisions according to + + align:start position:0% +but so two major divisions according to + + + align:start position:0% +but so two major divisions according to +this classification but if you do it + + align:start position:0% +this classification but if you do it + + + align:start position:0% +this classification but if you do it +just structurally you would say + + align:start position:0% +just structurally you would say + + + align:start position:0% +just structurally you would say +pyramidal and + + align:start position:0% +pyramidal and + + + align:start position:0% +pyramidal and +stellite are the two major types and + + align:start position:0% +stellite are the two major types and + + + align:start position:0% +stellite are the two major types and +that's what here's from now this book he + + align:start position:0% +that's what here's from now this book he + + + align:start position:0% +that's what here's from now this book he +shows the small param to sell and say + + align:start position:0% +shows the small param to sell and say + + + align:start position:0% +shows the small param to sell and say +you're six and then he shows a couple of + + align:start position:0% +you're six and then he shows a couple of + + + align:start position:0% +you're six and then he shows a couple of +stellates and he has a more elaborate + + align:start position:0% +stellates and he has a more elaborate + + + align:start position:0% +stellates and he has a more elaborate +picture of their + + align:start position:0% +picture of their + + + align:start position:0% +picture of their +both the dendrites and the axons + + align:start position:0% +both the dendrites and the axons + + + align:start position:0% +both the dendrites and the axons +yeah + + align:start position:0% +yeah + + + align:start position:0% +yeah +whereas other anatomy books like brodol + + align:start position:0% +whereas other anatomy books like brodol + + + align:start position:0% +whereas other anatomy books like brodol +as a simplified picture in this case + + align:start position:0% +as a simplified picture in this case + + + align:start position:0% +as a simplified picture in this case +interneurons we're showing some of those + + align:start position:0% +interneurons we're showing some of those + + + align:start position:0% +interneurons we're showing some of those +same cells that are in the other picture + + align:start position:0% +same cells that are in the other picture + + + align:start position:0% +same cells that are in the other picture +but he's put the axons in red like they + + align:start position:0% +but he's put the axons in red like they + + + align:start position:0% +but he's put the axons in red like they +did + + align:start position:0% +did + + + align:start position:0% +did +simplified the dendritic tree a little + + align:start position:0% +simplified the dendritic tree a little + + + align:start position:0% +simplified the dendritic tree a little +bit and shows + + align:start position:0% +bit and shows + + + align:start position:0% +bit and shows +indicates how they terminate these are + + align:start position:0% +indicates how they terminate these are + + + align:start position:0% +indicates how they terminate these are +all Gaba agencies + + align:start position:0% +all Gaba agencies + + + align:start position:0% +all Gaba agencies +except this one + + align:start position:0% +except this one + + + align:start position:0% +except this one +probably an excited for yourself and + + align:start position:0% +probably an excited for yourself and + + + align:start position:0% +probably an excited for yourself and +therefore + + align:start position:0% +therefore + + + align:start position:0% +therefore +so this would be the only one + + align:start position:0% + + + + align:start position:0% + +is classified over here because it's + + align:start position:0% +is classified over here because it's + + + align:start position:0% +is classified over here because it's +tiny excitatory so + + align:start position:0% +tiny excitatory so + + + align:start position:0% +tiny excitatory so +all right + + align:start position:0% + + + + align:start position:0% + +then I I point out here that not all + + align:start position:0% +then I I point out here that not all + + + align:start position:0% +then I I point out here that not all +local interconnections + + align:start position:0% +local interconnections + + + align:start position:0% +local interconnections +within the neocortex are made by this + + align:start position:0% +within the neocortex are made by this + + + align:start position:0% +within the neocortex are made by this +short acts on internet so I'm talking + + align:start position:0% +short acts on internet so I'm talking + + + align:start position:0% +short acts on internet so I'm talking +about just locally + + align:start position:0% +about just locally + + + align:start position:0% +about just locally +that in the same column or between one + + align:start position:0% +that in the same column or between one + + + align:start position:0% +that in the same column or between one +column in nearby columns they're made by + + align:start position:0% +column in nearby columns they're made by + + + align:start position:0% +column in nearby columns they're made by +by axon collapse + + align:start position:0% +by axon collapse + + + align:start position:0% +by axon collapse +almost all pictures of this that you see + + align:start position:0% +almost all pictures of this that you see + + + align:start position:0% +almost all pictures of this that you see +in textbooks never show this elaborate + + align:start position:0% +in textbooks never show this elaborate + + + align:start position:0% +in textbooks never show this elaborate +collateralization of the axon but the + + align:start position:0% +collateralization of the axon but the + + + align:start position:0% +collateralization of the axon but the +shy Bells were very good anatomists they + + align:start position:0% +shy Bells were very good anatomists they + + + align:start position:0% +shy Bells were very good anatomists they +published some of the best Golgi + + align:start position:0% +published some of the best Golgi + + + align:start position:0% +published some of the best Golgi +pictures and modern anatomical + + align:start position:0% +pictures and modern anatomical + + + align:start position:0% +pictures and modern anatomical +literature + + align:start position:0% +literature + + + align:start position:0% +literature +and this here they're showing + + align:start position:0% +and this here they're showing + + + align:start position:0% +and this here they're showing +that the dendritic spread of + + align:start position:0% +that the dendritic spread of + + + align:start position:0% +that the dendritic spread of +in the cat + + align:start position:0% +in the cat + + + align:start position:0% +in the cat +of neocortical cells averaged around 500 + + align:start position:0% +of neocortical cells averaged around 500 + + + align:start position:0% +of neocortical cells averaged around 500 +microns + + align:start position:0% +microns + + + align:start position:0% +microns +whereas the Axon collaterals + + align:start position:0% +whereas the Axon collaterals + + + align:start position:0% +whereas the Axon collaterals +collaterals of the initial segment of + + align:start position:0% +collaterals of the initial segment of + + + align:start position:0% +collaterals of the initial segment of +the axon in this case the actions are + + align:start position:0% +the axon in this case the actions are + + + align:start position:0% +the axon in this case the actions are +all going out + + align:start position:0% + + + + align:start position:0% + +this one to other cortical areas these + + align:start position:0% +this one to other cortical areas these + + + align:start position:0% +this one to other cortical areas these +two are two + + align:start position:0% +two are two + + + align:start position:0% +two are two +to the thalamus and brainstem and spinal + + align:start position:0% +to the thalamus and brainstem and spinal + + + align:start position:0% +to the thalamus and brainstem and spinal +cord + + align:start position:0% +cord + + + align:start position:0% +cord +look how much they covered 3 000 so + + align:start position:0% +look how much they covered 3 000 so + + + align:start position:0% +look how much they covered 3 000 so +three millimeters + + align:start position:0% +three millimeters + + + align:start position:0% +three millimeters +very so huge numbers of local + + align:start position:0% +very so huge numbers of local + + + align:start position:0% +very so huge numbers of local +connections are formed by these accent + + align:start position:0% +connections are formed by these accent + + + align:start position:0% +connections are formed by these accent +collaterals + + align:start position:0% + + + + align:start position:0% + +okay now we you should be able to answer + + align:start position:0% +okay now we you should be able to answer + + + align:start position:0% +okay now we you should be able to answer +this how have neuroscientists Define + + align:start position:0% +this how have neuroscientists Define + + + align:start position:0% +this how have neuroscientists Define +cortical layers and cortical columns + + align:start position:0% +cortical layers and cortical columns + + + align:start position:0% +cortical layers and cortical columns +divided into anatomical methods + + align:start position:0% +divided into anatomical methods + + + align:start position:0% +divided into anatomical methods +or the missile method and also the Golgi + + align:start position:0% +or the missile method and also the Golgi + + + align:start position:0% +or the missile method and also the Golgi +method if it's so dominated + + align:start position:0% +method if it's so dominated + + + align:start position:0% +method if it's so dominated +also fiber stains + + align:start position:0% +also fiber stains + + + align:start position:0% +also fiber stains +but what about the functional side + + align:start position:0% +but what about the functional side + + + align:start position:0% +but what about the functional side +electrophysiology + + align:start position:0% +electrophysiology + + + align:start position:0% +electrophysiology +our initial definition of columns came + + align:start position:0% +our initial definition of columns came + + + align:start position:0% +our initial definition of columns came +from electrophysiologists putting + + align:start position:0% +from electrophysiologists putting + + + align:start position:0% +from electrophysiologists putting +microelectrines and seeing functional + + align:start position:0% +microelectrines and seeing functional + + + align:start position:0% +microelectrines and seeing functional +differences + + align:start position:0% +differences + + + align:start position:0% +differences +between one Regional cortex and + + align:start position:0% +between one Regional cortex and + + + align:start position:0% +between one Regional cortex and +immediately adjacent like in the visual + + align:start position:0% +immediately adjacent like in the visual + + + align:start position:0% +immediately adjacent like in the visual +cortex you would find that cells here + + align:start position:0% +cortex you would find that cells here + + + align:start position:0% +cortex you would find that cells here +respond to one eye + + align:start position:0% +respond to one eye + + + align:start position:0% +respond to one eye +cells here respond to the next day then + + align:start position:0% +cells here respond to the next day then + + + align:start position:0% +cells here respond to the next day then +back to the first die and the second and + + align:start position:0% +back to the first die and the second and + + + align:start position:0% +back to the first die and the second and +so forth you know so physiological + + align:start position:0% +so forth you know so physiological + + + align:start position:0% +so forth you know so physiological +methods and various anatomical methods + + align:start position:0% +methods and various anatomical methods + + + align:start position:0% +methods and various anatomical methods +there are molecular methods in addition + + align:start position:0% +there are molecular methods in addition + + + align:start position:0% +there are molecular methods in addition +especially for layers + + align:start position:0% +especially for layers + + + align:start position:0% +especially for layers +if you look back in chapter two I had a + + align:start position:0% +if you look back in chapter two I had a + + + align:start position:0% +if you look back in chapter two I had a +picture where they had antibodies that + + align:start position:0% +picture where they had antibodies that + + + align:start position:0% +picture where they had antibodies that +bound to cells in specific laminate + + align:start position:0% +bound to cells in specific laminate + + + align:start position:0% +bound to cells in specific laminate +specific layers of the neocortex so + + align:start position:0% +specific layers of the neocortex so + + + align:start position:0% +specific layers of the neocortex so +that's still one more method + + align:start position:0% +that's still one more method + + + align:start position:0% +that's still one more method +molecular methods used for neuroanatomy + + align:start position:0% +molecular methods used for neuroanatomy + + + align:start position:0% +molecular methods used for neuroanatomy +and this just summarizes these pictures + + align:start position:0% +and this just summarizes these pictures + + + align:start position:0% +and this just summarizes these pictures +I wanted this is the one I used in the + + align:start position:0% +I wanted this is the one I used in the + + + align:start position:0% +I wanted this is the one I used in the +book + + align:start position:0% +book + + + align:start position:0% +book +uh and this is the one that usually you + + align:start position:0% +uh and this is the one that usually you + + + align:start position:0% +uh and this is the one that usually you +see in books + + align:start position:0% +see in books + + + align:start position:0% +see in books +and people will wonder why did I choose + + align:start position:0% +and people will wonder why did I choose + + + align:start position:0% +and people will wonder why did I choose +this one + + align:start position:0% +this one + + + align:start position:0% +this one +by an American neuronatalyst + + align:start position:0% +by an American neuronatalyst + + + align:start position:0% +by an American neuronatalyst +and not the one that's always published + + align:start position:0% +and not the one that's always published + + + align:start position:0% +and not the one that's always published +and that's because I insisted + + align:start position:0% +and that's because I insisted + + + align:start position:0% +and that's because I insisted +with Amy's help + + align:start position:0% +with Amy's help + + + align:start position:0% +with Amy's help +finding the sources + + align:start position:0% +finding the sources + + + align:start position:0% +finding the sources +I didn't want it if I found people cited + + align:start position:0% +I didn't want it if I found people cited + + + align:start position:0% +I didn't want it if I found people cited +a certain Source I found the source + + align:start position:0% +a certain Source I found the source + + + align:start position:0% +a certain Source I found the source +and I found out it was wrong again and + + align:start position:0% +and I found out it was wrong again and + + + align:start position:0% +and I found out it was wrong again and +again and again + + align:start position:0% +again and again + + + align:start position:0% +again and again +because people + + align:start position:0% +because people + + + align:start position:0% +because people +usually aren't that careful in their + + align:start position:0% +usually aren't that careful in their + + + align:start position:0% +usually aren't that careful in their +scholarship I just wanted to point that + + align:start position:0% +scholarship I just wanted to point that + + + align:start position:0% +scholarship I just wanted to point that +out to you you can't believe everything + + align:start position:0% +out to you you can't believe everything + + + align:start position:0% +out to you you can't believe everything +you read + + align:start position:0% +you read + + + align:start position:0% +you read +he's an in science okay especially + + align:start position:0% +he's an in science okay especially + + + align:start position:0% +he's an in science okay especially +scientists aren't always very good + + align:start position:0% +scientists aren't always very good + + + align:start position:0% +scientists aren't always very good +historians + + align:start position:0% +historians + + + align:start position:0% +historians +just thought you might like to know that + + align:start position:0% +just thought you might like to know that + + + align:start position:0% +just thought you might like to know that +and uh we'll have to stop there + + align:start position:0% +and uh we'll have to stop there + + + align:start position:0% +and uh we'll have to stop there +we'll come back and go through a few of + + align:start position:0% +we'll come back and go through a few of + + + align:start position:0% +we'll come back and go through a few of +these things and focus on the pictures + + align:start position:0% +these things and focus on the pictures + + + align:start position:0% +these things and focus on the pictures +make sure you're understanding the + + align:start position:0% +make sure you're understanding the + + + align:start position:0% +make sure you're understanding the +pictures okay they're all posted + + align:start position:0% +pictures okay they're all posted + + + align:start position:0% +pictures okay they're all posted +talks about cortical types cortical + + align:start position:0% +talks about cortical types cortical + + + align:start position:0% +talks about cortical types cortical +columns how you can Define them + + align:start position:0% +columns how you can Define them + + + align:start position:0% +columns how you can Define them +anatomically + + align:start position:0% +anatomically + + + align:start position:0% +anatomically +layers as well and a few of the things + + align:start position:0% +layers as well and a few of the things + + + align:start position:0% +layers as well and a few of the things +that are commonly stated in the case + + align:start position:0% +that are commonly stated in the case + + + align:start position:0% +that are commonly stated in the case +come back there + + align:start position:0% + + + + align:start position:0% + +in the next class and I know we can get + + align:start position:0% +in the next class and I know we can get + + + align:start position:0% +in the next class and I know we can get +through these and I hope hopefully we + + align:start position:0% +through these and I hope hopefully we + + + align:start position:0% +through these and I hope hopefully we +can get a little better + + align:start position:0% +can get a little better + + + align:start position:0% +can get a little better +the next chapter as well \ No newline at end of file diff --git a/xsP-S7yKaRA.txt b/xsP-S7yKaRA.txt new file mode 100644 index 0000000000000000000000000000000000000000..e5714973501ac9419b2a58a60629c1498368d5f8 --- /dev/null +++ b/xsP-S7yKaRA.txt @@ -0,0 +1,5899 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT OpenCourseWare continue to + + align:start position:0% +will help MIT OpenCourseWare continue to + + + align:start position:0% +will help MIT OpenCourseWare continue to +offer high quality educational resources + + align:start position:0% +offer high quality educational resources + + + align:start position:0% +offer high quality educational resources +for free + + align:start position:0% +for free + + + align:start position:0% +for free +to make a donation or to view additional + + align:start position:0% +to make a donation or to view additional + + + align:start position:0% +to make a donation or to view additional +materials from hundreds of MIT courses + + align:start position:0% +materials from hundreds of MIT courses + + + align:start position:0% +materials from hundreds of MIT courses +visit MIT opencourseware at ocw.mit.edu + + align:start position:0% + + + + align:start position:0% + +okay let me make a start on the left you + + align:start position:0% +okay let me make a start on the left you + + + align:start position:0% +okay let me make a start on the left you +see the topic for today so we're doing + + align:start position:0% +see the topic for today so we're doing + + + align:start position:0% +see the topic for today so we're doing +pretty well this completes my sort of + + align:start position:0% +pretty well this completes my sort of + + + align:start position:0% +pretty well this completes my sort of +review of the highlights of linear + + align:start position:0% +review of the highlights of linear + + + align:start position:0% +review of the highlights of linear +algebra so that's five lectures and it + + align:start position:0% +algebra so that's five lectures and it + + + align:start position:0% +algebra so that's five lectures and it +I'll follow up on those five points + + align:start position:0% +I'll follow up on those five points + + + align:start position:0% +I'll follow up on those five points +because the neat part is it really ties + + align:start position:0% +because the neat part is it really ties + + + align:start position:0% +because the neat part is it really ties +together the whole subject I can values + + align:start position:0% +together the whole subject I can values + + + align:start position:0% +together the whole subject I can values +energy a transpose a determinants pivots + + align:start position:0% +energy a transpose a determinants pivots + + + align:start position:0% +energy a transpose a determinants pivots +they all come together each one gives a + + align:start position:0% +they all come together each one gives a + + + align:start position:0% +they all come together each one gives a +test for positive definite matrices so + + align:start position:0% +test for positive definite matrices so + + + align:start position:0% +test for positive definite matrices so +all that's where I'm going clear is + + align:start position:0% +all that's where I'm going clear is + + + align:start position:0% +all that's where I'm going clear is +hoping to come in for a little bit of + + align:start position:0% +hoping to come in for a little bit of + + + align:start position:0% +hoping to come in for a little bit of +the class to ask if anybody has started + + align:start position:0% +the class to ask if anybody has started + + + align:start position:0% +the class to ask if anybody has started +on the on the homework and got Julia + + align:start position:0% +on the on the homework and got Julia + + + align:start position:0% +on the on the homework and got Julia +rolling and got a yes from the auto + + align:start position:0% +rolling and got a yes from the auto + + + align:start position:0% +rolling and got a yes from the auto +grader did anybody is anybody like no + + align:start position:0% +grader did anybody is anybody like no + + + align:start position:0% +grader did anybody is anybody like no +you're taking a chance right Julia in + + align:start position:0% +you're taking a chance right Julia in + + + align:start position:0% +you're taking a chance right Julia in +principle works but in practice it's + + align:start position:0% +principle works but in practice it's + + + align:start position:0% +principle works but in practice it's +always an adventure the first time so we + + align:start position:0% +always an adventure the first time so we + + + align:start position:0% +always an adventure the first time so we +chose this lab on convolution because it + + align:start position:0% +chose this lab on convolution because it + + + align:start position:0% +chose this lab on convolution because it +was the first lab last time last year + + align:start position:0% +was the first lab last time last year + + + align:start position:0% +was the first lab last time last year +and it doesn't ask for much mass at all + + align:start position:0% +and it doesn't ask for much mass at all + + + align:start position:0% +and it doesn't ask for much mass at all +really just creating a matrix and + + align:start position:0% +really just creating a matrix and + + + align:start position:0% +really just creating a matrix and +getting the auto grader to say yes + + align:start position:0% +getting the auto grader to say yes + + + align:start position:0% +getting the auto grader to say yes +that's the right matrix so and we'll see + + align:start position:0% +that's the right matrix so and we'll see + + + align:start position:0% +that's the right matrix so and we'll see +that matrix + + align:start position:0% +that matrix + + + align:start position:0% +that matrix +we'll see this idea of convolution + + align:start position:0% +we'll see this idea of convolution + + + align:start position:0% +we'll see this idea of convolution +in the right time at the right time + + align:start position:0% +in the right time at the right time + + + align:start position:0% +in the right time at the right time +which is not that far off its signal + + align:start position:0% +which is not that far off its signal + + + align:start position:0% +which is not that far off its signal +processing and it's early in part three + + align:start position:0% +processing and it's early in part three + + + align:start position:0% +processing and it's early in part three +of the book okay so that if Claire comes + + align:start position:0% +of the book okay so that if Claire comes + + + align:start position:0% +of the book okay so that if Claire comes +in she'll answer questions otherwise I + + align:start position:0% +in she'll answer questions otherwise I + + + align:start position:0% +in she'll answer questions otherwise I +guess it would be emailing questions to + + align:start position:0% +guess it would be emailing questions to + + + align:start position:0% +guess it would be emailing questions to +I realize that the deadline is not on + + align:start position:0% +I realize that the deadline is not on + + + align:start position:0% +I realize that the deadline is not on +top of you so and you've got a whole + + align:start position:0% +top of you so and you've got a whole + + + align:start position:0% +top of you so and you've got a whole +weekend to make Julia fly alright so + + align:start position:0% +weekend to make Julia fly alright so + + + align:start position:0% +weekend to make Julia fly alright so +I'll start on the math then we had + + align:start position:0% +I'll start on the math then we had + + + align:start position:0% +I'll start on the math then we had +symmetric matrix I can values of + + align:start position:0% +symmetric matrix I can values of + + + align:start position:0% +symmetric matrix I can values of +matrices and specially symmetric + + align:start position:0% +matrices and specially symmetric + + + align:start position:0% +matrices and specially symmetric +matrices and those have real eigenvalues + + align:start position:0% +matrices and those have real eigenvalues + + + align:start position:0% +matrices and those have real eigenvalues +and I'll quickly show why and orthogonal + + align:start position:0% +and I'll quickly show why and orthogonal + + + align:start position:0% +and I'll quickly show why and orthogonal +eigenvectors and I'll quickly show why + + align:start position:0% +eigenvectors and I'll quickly show why + + + align:start position:0% +eigenvectors and I'll quickly show why +but I want to move to the new idea + + align:start position:0% +but I want to move to the new idea + + + align:start position:0% +but I want to move to the new idea +positive definite matrices so these are + + align:start position:0% +positive definite matrices so these are + + + align:start position:0% +positive definite matrices so these are +the best of the symmetric matrices there + + align:start position:0% +the best of the symmetric matrices there + + + align:start position:0% +the best of the symmetric matrices there +are symmetric matrices that have + + align:start position:0% +are symmetric matrices that have + + + align:start position:0% +are symmetric matrices that have +positive eigenvalues that's the easy way + + align:start position:0% +positive eigenvalues that's the easy way + + + align:start position:0% +positive eigenvalues that's the easy way +to remember positive definite matrices + + align:start position:0% +to remember positive definite matrices + + + align:start position:0% +to remember positive definite matrices +they have positive eigenvalues but it's + + align:start position:0% +they have positive eigenvalues but it's + + + align:start position:0% +they have positive eigenvalues but it's +certainly not the easy way to test if I + + align:start position:0% +certainly not the easy way to test if I + + + align:start position:0% +certainly not the easy way to test if I +give you a matrix like that well that's + + align:start position:0% +give you a matrix like that well that's + + + align:start position:0% +give you a matrix like that well that's +only two by two we could actually find + + align:start position:0% +only two by two we could actually find + + + align:start position:0% +only two by two we could actually find +the eigenvalues but we would like to + + align:start position:0% +the eigenvalues but we would like to + + + align:start position:0% +the eigenvalues but we would like to +have other tests easier tests which + + align:start position:0% +have other tests easier tests which + + + align:start position:0% +have other tests easier tests which +would be which would be equivalent to a + + align:start position:0% +would be which would be equivalent to a + + + align:start position:0% +would be which would be equivalent to a +positive eigenvalues so these other + + align:start position:0% +positive eigenvalues so these other + + + align:start position:0% +positive eigenvalues so these other +every one of those five tests any one of + + align:start position:0% +every one of those five tests any one of + + + align:start position:0% +every one of those five tests any one of +those five tests is is all you need so + + align:start position:0% +those five tests is is all you need so + + + align:start position:0% +those five tests is is all you need so +let me start with that example and ask + + align:start position:0% +let me start with that example and ask + + + align:start position:0% +let me start with that example and ask +you to look and then I'm gonna discuss + + align:start position:0% +you to look and then I'm gonna discuss + + + align:start position:0% +you to look and then I'm gonna discuss +those five separate points but can you + + align:start position:0% +those five separate points but can you + + + align:start position:0% +those five separate points but can you +see well my question is is that matrix s + + align:start position:0% +see well my question is is that matrix s + + + align:start position:0% +see well my question is is that matrix s +it's obviously symmetric is it positive + + align:start position:0% +it's obviously symmetric is it positive + + + align:start position:0% +it's obviously symmetric is it positive +definite or not okay so you could + + align:start position:0% +definite or not okay so you could + + + align:start position:0% +definite or not okay so you could +compute its eigenvalues since it's two + + align:start position:0% +compute its eigenvalues since it's two + + + align:start position:0% +compute its eigenvalues since it's two +by two its energy I'll come back to that + + align:start position:0% +by two its energy I'll come back to that + + + align:start position:0% +by two its energy I'll come back to that +because that's the most important one + + align:start position:0% +because that's the most important one + + + align:start position:0% +because that's the most important one +number two is really fundamental number + + align:start position:0% +number two is really fundamental number + + + align:start position:0% +number two is really fundamental number +three would ask you to factor that well + + align:start position:0% +three would ask you to factor that well + + + align:start position:0% +three would ask you to factor that well +that's you don't + + align:start position:0% +that's you don't + + + align:start position:0% +that's you don't +to take time with that well what do you + + align:start position:0% +to take time with that well what do you + + + align:start position:0% +to take time with that well what do you +think is it positive definite or not I + + align:start position:0% +think is it positive definite or not I + + + align:start position:0% +think is it positive definite or not I +see a expert in the front row saying no + + align:start position:0% +see a expert in the front row saying no + + + align:start position:0% +see a expert in the front row saying no +and why is it no the answer is no that's + + align:start position:0% +and why is it no the answer is no that's + + + align:start position:0% +and why is it no the answer is no that's +not a positive definite matrix where + + align:start position:0% +not a positive definite matrix where + + + align:start position:0% +not a positive definite matrix where +does it let us down it's got all + + align:start position:0% +does it let us down it's got all + + + align:start position:0% +does it let us down it's got all +positive numbers but that's not what + + align:start position:0% +positive numbers but that's not what + + + align:start position:0% +positive numbers but that's not what +we're asking we're asking positive + + align:start position:0% +we're asking we're asking positive + + + align:start position:0% +we're asking we're asking positive +eigenvalues positive determinants + + align:start position:0% +eigenvalues positive determinants + + + align:start position:0% +eigenvalues positive determinants +positive pivots so how does it let us + + align:start position:0% +positive pivots so how does it let us + + + align:start position:0% +positive pivots so how does it let us +down well which which is the easy test + + align:start position:0% +down well which which is the easy test + + + align:start position:0% +down well which which is the easy test +to see that it fails determinant the + + align:start position:0% +to see that it fails determinant the + + + align:start position:0% +to see that it fails determinant the +determinant is 15-16 so negative and + + align:start position:0% +determinant is 15-16 so negative and + + + align:start position:0% +determinant is 15-16 so negative and +that's what so how's the determinate + + align:start position:0% +that's what so how's the determinate + + + align:start position:0% +that's what so how's the determinate +connected to the eigenvalues everybody + + align:start position:0% +connected to the eigenvalues everybody + + + align:start position:0% +connected to the eigenvalues everybody +yep it's the product so the two + + align:start position:0% +yep it's the product so the two + + + align:start position:0% +yep it's the product so the two +eigenvalues of s they're real of course + + align:start position:0% +eigenvalues of s they're real of course + + + align:start position:0% +eigenvalues of s they're real of course +and they multiply to give the + + align:start position:0% +and they multiply to give the + + + align:start position:0% +and they multiply to give the +determinant which is minus one so one of + + align:start position:0% +determinant which is minus one so one of + + + align:start position:0% +determinant which is minus one so one of +them is negative and one of them is + + align:start position:0% +them is negative and one of them is + + + align:start position:0% +them is negative and one of them is +positive this matrix is an indefinite + + align:start position:0% +positive this matrix is an indefinite + + + align:start position:0% +positive this matrix is an indefinite +matrix indefinite so how could I make it + + align:start position:0% +matrix indefinite so how could I make it + + + align:start position:0% +matrix indefinite so how could I make it +positive definite okay just we can just + + align:start position:0% +positive definite okay just we can just + + + align:start position:0% +positive definite okay just we can just +play with an example and then we see + + align:start position:0% +play with an example and then we see + + + align:start position:0% +play with an example and then we see +these things happening let's see okay + + align:start position:0% +these things happening let's see okay + + + align:start position:0% +these things happening let's see okay +well what shall I put in in place of the + + align:start position:0% +well what shall I put in in place of the + + + align:start position:0% +well what shall I put in in place of the +five for example I could lower the four + + align:start position:0% +five for example I could lower the four + + + align:start position:0% +five for example I could lower the four +or I can up the five or up the three I + + align:start position:0% +or I can up the five or up the three I + + + align:start position:0% +or I can up the five or up the three I +can make the diagonal entries if I add + + align:start position:0% +can make the diagonal entries if I add + + + align:start position:0% +can make the diagonal entries if I add +stuff to the main diagonal I'm making it + + align:start position:0% +stuff to the main diagonal I'm making it + + + align:start position:0% +stuff to the main diagonal I'm making it +more positive so that's sort of + + align:start position:0% +more positive so that's sort of + + + align:start position:0% +more positive so that's sort of +straightforward way so what number in + + align:start position:0% +straightforward way so what number in + + + align:start position:0% +straightforward way so what number in +there would be safe six okay six would + + align:start position:0% +there would be safe six okay six would + + + align:start position:0% +there would be safe six okay six would +be safe if I go up from five to six I've + + align:start position:0% +be safe if I go up from five to six I've + + + align:start position:0% +be safe if I go up from five to six I've +got to do yeah so when I say here + + align:start position:0% +got to do yeah so when I say here + + + align:start position:0% +got to do yeah so when I say here +leading determinants what does that mean + + align:start position:0% +leading determinants what does that mean + + + align:start position:0% +leading determinants what does that mean +that so that's a that word leading means + + align:start position:0% +that so that's a that word leading means + + + align:start position:0% +that so that's a that word leading means +something it means that I take the one + + align:start position:0% +something it means that I take the one + + + align:start position:0% +something it means that I take the one +by one determinant it would have to pass + + align:start position:0% +by one determinant it would have to pass + + + align:start position:0% +by one determinant it would have to pass +that just the determinant itself would + + align:start position:0% +that just the determinant itself would + + + align:start position:0% +that just the determinant itself would +not do it let me give you an example + + align:start position:0% +not do it let me give you an example + + + align:start position:0% +not do it let me give you an example +no.4 let me take minus 3 and minus 6 + + align:start position:0% +no.4 let me take minus 3 and minus 6 + + + align:start position:0% +no.4 let me take minus 3 and minus 6 +that would have the same determinant but + + align:start position:0% +that would have the same determinant but + + + align:start position:0% +that would have the same determinant but +it's write the determinant would still + + align:start position:0% +it's write the determinant would still + + + align:start position:0% +it's write the determinant would still +be 18 minus 16 - but it fails the tests + + align:start position:0% +be 18 minus 16 - but it fails the tests + + + align:start position:0% +be 18 minus 16 - but it fails the tests +on the on the one by one and this passes + + align:start position:0% +on the on the one by one and this passes + + + align:start position:0% +on the on the one by one and this passes +this passes the one by one test and the + + align:start position:0% +this passes the one by one test and the + + + align:start position:0% +this passes the one by one test and the +two by two tests so that's what this + + align:start position:0% +two by two tests so that's what this + + + align:start position:0% +two by two tests so that's what this +means here leading determinants are from + + align:start position:0% +means here leading determinants are from + + + align:start position:0% +means here leading determinants are from +the upper left you have to check end + + align:start position:0% +the upper left you have to check end + + + align:start position:0% +the upper left you have to check end +things because you've got n eigenvalues + + align:start position:0% +things because you've got n eigenvalues + + + align:start position:0% +things because you've got n eigenvalues +and those are the end tests right and + + align:start position:0% +and those are the end tests right and + + + align:start position:0% +and those are the end tests right and +have you noticed the connection to + + align:start position:0% +have you noticed the connection to + + + align:start position:0% +have you noticed the connection to +pivots so let's just remember that small + + align:start position:0% +pivots so let's just remember that small + + + align:start position:0% +pivots so let's just remember that small +item what would be the pivots because we + + align:start position:0% +item what would be the pivots because we + + + align:start position:0% +item what would be the pivots because we +didn't take a long time on elimination + + align:start position:0% +didn't take a long time on elimination + + + align:start position:0% +didn't take a long time on elimination +so what would be the pivots for for that + + align:start position:0% +so what would be the pivots for for that + + + align:start position:0% +so what would be the pivots for for that +matrix 3 4 4 second well what's the + + align:start position:0% +matrix 3 4 4 second well what's the + + + align:start position:0% +matrix 3 4 4 second well what's the +first pivot 3 sitting there the 1 1 + + align:start position:0% +first pivot 3 sitting there the 1 1 + + + align:start position:0% +first pivot 3 sitting there the 1 1 +entry would be the first pivot so the + + align:start position:0% +entry would be the first pivot so the + + + align:start position:0% +entry would be the first pivot so the +pivots will be 3 and what's the second + + align:start position:0% +pivots will be 3 and what's the second + + + align:start position:0% +pivots will be 3 and what's the second +pivot well maybe to see it clearly you + + align:start position:0% +pivot well maybe to see it clearly you + + + align:start position:0% +pivot well maybe to see it clearly you +want me to take that elimination step + + align:start position:0% +want me to take that elimination step + + + align:start position:0% +want me to take that elimination step +why don't I do it just so you'll see it + + align:start position:0% +why don't I do it just so you'll see it + + + align:start position:0% +why don't I do it just so you'll see it +here so elimination would subtract some + + align:start position:0% +here so elimination would subtract some + + + align:start position:0% +here so elimination would subtract some +multiple of Row one from Row two I I + + align:start position:0% +multiple of Row one from Row two I I + + + align:start position:0% +multiple of Row one from Row two I I +would leave Row one alone I would + + align:start position:0% +would leave Row one alone I would + + + align:start position:0% +would leave Row one alone I would +subtract some multiple to get a zero + + align:start position:0% +subtract some multiple to get a zero + + + align:start position:0% +subtract some multiple to get a zero +there and what what's the multiple + + align:start position:0% +there and what what's the multiple + + + align:start position:0% +there and what what's the multiple +what's the multiplier in that was 4/3 + + align:start position:0% +what's the multiplier in that was 4/3 + + + align:start position:0% +what's the multiplier in that was 4/3 +4/3 times Row one away from Row two + + align:start position:0% +4/3 times Row one away from Row two + + + align:start position:0% +4/3 times Row one away from Row two +would produce that 0 but 4/3 times the 4 + + align:start position:0% +would produce that 0 but 4/3 times the 4 + + + align:start position:0% +would produce that 0 but 4/3 times the 4 +that would be 16 thirds and we're + + align:start position:0% +that would be 16 thirds and we're + + + align:start position:0% +that would be 16 thirds and we're +subtracting it from 18 thirds I think + + align:start position:0% +subtracting it from 18 thirds I think + + + align:start position:0% +subtracting it from 18 thirds I think +we've got two thirds left so the pivots + + align:start position:0% +we've got two thirds left so the pivots + + + align:start position:0% +we've got two thirds left so the pivots +which is this in elimination or the 3 + + align:start position:0% +which is this in elimination or the 3 + + + align:start position:0% +which is this in elimination or the 3 +and the 2 thirds and of course they're + + align:start position:0% +and the 2 thirds and of course they're + + + align:start position:0% +and the 2 thirds and of course they're +positive and actually you see the + + align:start position:0% +positive and actually you see the + + + align:start position:0% +positive and actually you see the +immediate connection + + align:start position:0% +immediate connection + + + align:start position:0% +immediate connection +this pivot is the 2 by 2 determinant + + align:start position:0% +this pivot is the 2 by 2 determinant + + + align:start position:0% +this pivot is the 2 by 2 determinant +divided by the 1 by 1 determinant the 2 + + align:start position:0% +divided by the 1 by 1 determinant the 2 + + + align:start position:0% +divided by the 1 by 1 determinant the 2 +by 2 determinant we figured out 18-49 ax + + align:start position:0% +by 2 determinant we figured out 18-49 ax + + + align:start position:0% +by 2 determinant we figured out 18-49 ax +16 was to the 1 by 1 determinant is 3 + + align:start position:0% +16 was to the 1 by 1 determinant is 3 + + + align:start position:0% +16 was to the 1 by 1 determinant is 3 +and sure enough that second pivot is 2/3 + + align:start position:0% +and sure enough that second pivot is 2/3 + + + align:start position:0% +and sure enough that second pivot is 2/3 +this is not so by example I'm + + align:start position:0% +this is not so by example I'm + + + align:start position:0% +this is not so by example I'm +illustrating what these different tests + + align:start position:0% +illustrating what these different tests + + + align:start position:0% +illustrating what these different tests +and again each test is all you need if + + align:start position:0% +and again each test is all you need if + + + align:start position:0% +and again each test is all you need if +it passes one test it passes them all + + align:start position:0% +it passes one test it passes them all + + + align:start position:0% +it passes one test it passes them all +and and we haven't found the eigenvalues + + align:start position:0% +and and we haven't found the eigenvalues + + + align:start position:0% +and and we haven't found the eigenvalues +let me do the energy can I do energy + + align:start position:0% +let me do the energy can I do energy + + + align:start position:0% +let me do the energy can I do energy +here okay so what's this I I'm saying + + align:start position:0% +here okay so what's this I I'm saying + + + align:start position:0% +here okay so what's this I I'm saying +that this is the really the great test + + align:start position:0% +that this is the really the great test + + + align:start position:0% +that this is the really the great test +that for me that's the definition of a + + align:start position:0% +that for me that's the definition of a + + + align:start position:0% +that for me that's the definition of a +positive definite matrix and the word + + align:start position:0% +positive definite matrix and the word + + + align:start position:0% +positive definite matrix and the word +energy comes in because it's quadratics + + align:start position:0% +energy comes in because it's quadratics + + + align:start position:0% +energy comes in because it's quadratics +away kinetic energy or potential energy + + align:start position:0% +away kinetic energy or potential energy + + + align:start position:0% +away kinetic energy or potential energy +so that's the energy in the vector X for + + align:start position:0% +so that's the energy in the vector X for + + + align:start position:0% +so that's the energy in the vector X for +this matrix so let me compute it X + + align:start position:0% +this matrix so let me compute it X + + + align:start position:0% +this matrix so let me compute it X +transpose X so let me put in s here the + + align:start position:0% +transpose X so let me put in s here the + + + align:start position:0% +transpose X so let me put in s here the +original s and let me put in an any + + align:start position:0% +original s and let me put in an any + + + align:start position:0% +original s and let me put in an any +vector X so say X Y or X 1 maybe + + align:start position:0% +vector X so say X Y or X 1 maybe + + + align:start position:0% +vector X so say X Y or X 1 maybe +do you like X X Y is easier so that's + + align:start position:0% +do you like X X Y is easier so that's + + + align:start position:0% +do you like X X Y is easier so that's +that's our vector X transpose this is + + align:start position:0% +that's our vector X transpose this is + + + align:start position:0% +that's our vector X transpose this is +our matrix s and here's our vector X so + + align:start position:0% +our matrix s and here's our vector X so + + + align:start position:0% +our matrix s and here's our vector X so +it's a function of x and y it's a pure + + align:start position:0% +it's a function of x and y it's a pure + + + align:start position:0% +it's a function of x and y it's a pure +quadratic function can you do you know + + align:start position:0% +quadratic function can you do you know + + + align:start position:0% +quadratic function can you do you know +what I get when I multiply that out I + + align:start position:0% +what I get when I multiply that out I + + + align:start position:0% +what I get when I multiply that out I +get I get a very simple important type + + align:start position:0% +get I get a very simple important type + + + align:start position:0% +get I get a very simple important type +of function shall we multiply it out + + align:start position:0% +of function shall we multiply it out + + + align:start position:0% +of function shall we multiply it out +let's see so I multiply that by that + + align:start position:0% +let's see so I multiply that by that + + + align:start position:0% +let's see so I multiply that by that +first so I get 3x plus 4y and 4x plus 6y + + align:start position:0% +first so I get 3x plus 4y and 4x plus 6y + + + align:start position:0% +first so I get 3x plus 4y and 4x plus 6y +it's what I'm getting from the these two + + align:start position:0% +it's what I'm getting from the these two + + + align:start position:0% +it's what I'm getting from the these two +and now I'm hitting that with the X Y + + align:start position:0% +and now I'm hitting that with the X Y + + + align:start position:0% +and now I'm hitting that with the X Y +and now I'm gonna see the energy and + + align:start position:0% +and now I'm gonna see the energy and + + + align:start position:0% +and now I'm gonna see the energy and +you'll see the pattern that's always + + align:start position:0% +you'll see the pattern that's always + + + align:start position:0% +you'll see the pattern that's always +what math is about what's the pattern so + + align:start position:0% +what math is about what's the pattern so + + + align:start position:0% +what math is about what's the pattern so +I have x times 3x 3x squared + iy x 6y + + align:start position:0% +I have x times 3x 3x squared + iy x 6y + + + align:start position:0% +I have x times 3x 3x squared + iy x 6y +that's 6 y square and I have x times 4y + + align:start position:0% +that's 6 y square and I have x times 4y + + + align:start position:0% +that's 6 y square and I have x times 4y +that's 4 XY z-- + iy times 4x that's for + + align:start position:0% +that's 4 XY z-- + iy times 4x that's for + + + align:start position:0% +that's 4 XY z-- + iy times 4x that's for +more XY so I've got all those terms + + align:start position:0% +more XY so I've got all those terms + + + align:start position:0% +more XY so I've got all those terms +every every term in every number in the + + align:start position:0% +every every term in every number in the + + + align:start position:0% +every every term in every number in the +matrix gives me a piece of the energy + + align:start position:0% +matrix gives me a piece of the energy + + + align:start position:0% +matrix gives me a piece of the energy +and you see that the diagonal numbers 3 + + align:start position:0% +and you see that the diagonal numbers 3 + + + align:start position:0% +and you see that the diagonal numbers 3 +& 6 those give me the diagonal pieces 3x + + align:start position:0% +& 6 those give me the diagonal pieces 3x + + + align:start position:0% +& 6 those give me the diagonal pieces 3x +squared + 6 y squared and then the crust + + align:start position:0% +squared + 6 y squared and then the crust + + + align:start position:0% +squared + 6 y squared and then the crust +but I maybe call them the cross terms + + align:start position:0% +but I maybe call them the cross terms + + + align:start position:0% +but I maybe call them the cross terms +those give me 4 XY + 4 XY so really 8 X + + align:start position:0% +those give me 4 XY + 4 XY so really 8 X + + + align:start position:0% +those give me 4 XY + 4 XY so really 8 X +Y so so you could call this thing 8 X Y + + align:start position:0% + + + + align:start position:0% + +so that's my function that's my + + align:start position:0% +so that's my function that's my + + + align:start position:0% +so that's my function that's my +quadratic that's my energy and I believe + + align:start position:0% +quadratic that's my energy and I believe + + + align:start position:0% +quadratic that's my energy and I believe +that that is greater than 0 let me graph + + align:start position:0% +that that is greater than 0 let me graph + + + align:start position:0% +that that is greater than 0 let me graph +the thing let me graph that energy + + align:start position:0% + + + + align:start position:0% + +okay so here's a graph of my function f + + align:start position:0% +okay so here's a graph of my function f + + + align:start position:0% +okay so here's a graph of my function f +of x and y here is X and here is y and + + align:start position:0% +of x and y here is X and here is y and + + + align:start position:0% +of x and y here is X and here is y and +of course that's on the graph + + align:start position:0% +of course that's on the graph + + + align:start position:0% +of course that's on the graph +zero zero at x equals zero y equals zero + + align:start position:0% +zero zero at x equals zero y equals zero + + + align:start position:0% +zero zero at x equals zero y equals zero +the function is clearly zero everybody's + + align:start position:0% +the function is clearly zero everybody's + + + align:start position:0% +the function is clearly zero everybody's +got his eye let me write that function + + align:start position:0% +got his eye let me write that function + + + align:start position:0% +got his eye let me write that function +again here 3 x squared 6 y squared 8 X Y + + align:start position:0% + + + + align:start position:0% + +actually you can see this is how I think + + align:start position:0% +actually you can see this is how I think + + + align:start position:0% +actually you can see this is how I think +about that that function so 3x squared + + align:start position:0% +about that that function so 3x squared + + + align:start position:0% +about that that function so 3x squared +is obviously carrying me upwards it's + + align:start position:0% +is obviously carrying me upwards it's + + + align:start position:0% +is obviously carrying me upwards it's +not it never goes negative 6y squared + + align:start position:0% +not it never goes negative 6y squared + + + align:start position:0% +not it never goes negative 6y squared +will never go negative 8 X Y can go + + align:start position:0% +will never go negative 8 X Y can go + + + align:start position:0% +will never go negative 8 X Y can go +negative right if x and y have opposite + + align:start position:0% +negative right if x and y have opposite + + + align:start position:0% +negative right if x and y have opposite +signs that that will go negative but the + + align:start position:0% +signs that that will go negative but the + + + align:start position:0% +signs that that will go negative but the +question is do these do these positive + + align:start position:0% +question is do these do these positive + + + align:start position:0% +question is do these do these positive +pieces overwhelm it and make the graph + + align:start position:0% +pieces overwhelm it and make the graph + + + align:start position:0% +pieces overwhelm it and make the graph +go up like a bowl and the answer is yes + + align:start position:0% +go up like a bowl and the answer is yes + + + align:start position:0% +go up like a bowl and the answer is yes +for a positive definite matrix so this + + align:start position:0% +for a positive definite matrix so this + + + align:start position:0% +for a positive definite matrix so this +is a graph of a positive definite matrix + + align:start position:0% +is a graph of a positive definite matrix + + + align:start position:0% +is a graph of a positive definite matrix +of a part of positive energy the energy + + align:start position:0% +of a part of positive energy the energy + + + align:start position:0% +of a part of positive energy the energy +of a positive definite matrix so this is + + align:start position:0% +of a positive definite matrix so this is + + + align:start position:0% +of a positive definite matrix so this is +the energy X transpose F X that I'm + + align:start position:0% +the energy X transpose F X that I'm + + + align:start position:0% +the energy X transpose F X that I'm +graph and there it is + + align:start position:0% +graph and there it is + + + align:start position:0% +graph and there it is +this is important this is important this + + align:start position:0% +this is important this is important this + + + align:start position:0% +this is important this is important this +is the kind of function we like X + + align:start position:0% +is the kind of function we like X + + + align:start position:0% +is the kind of function we like X +transpose X where s is positive definite + + align:start position:0% +transpose X where s is positive definite + + + align:start position:0% +transpose X where s is positive definite +so the function goes up like that this + + align:start position:0% +so the function goes up like that this + + + align:start position:0% +so the function goes up like that this +is what deep learning is about this + + align:start position:0% +is what deep learning is about this + + + align:start position:0% +is what deep learning is about this +could be a loss function that you that + + align:start position:0% +could be a loss function that you that + + + align:start position:0% +could be a loss function that you that +you minimize it could depend on a + + align:start position:0% +you minimize it could depend on a + + + align:start position:0% +you minimize it could depend on a +hundred thousand variables or more and + + align:start position:0% +hundred thousand variables or more and + + + align:start position:0% +hundred thousand variables or more and +it could come from the the error in the + + align:start position:0% +it could come from the the error in the + + + align:start position:0% +it could come from the the error in the +difference between training data and + + align:start position:0% +difference between training data and + + + align:start position:0% +difference between training data and +your + + align:start position:0% +your + + + align:start position:0% +your +and the number you get the loss would be + + align:start position:0% +and the number you get the loss would be + + + align:start position:0% +and the number you get the loss would be +some expression like that well I'll make + + align:start position:0% +some expression like that well I'll make + + + align:start position:0% +some expression like that well I'll make +sense of those words as soon as I can + + align:start position:0% +sense of those words as soon as I can + + + align:start position:0% +sense of those words as soon as I can +what I want to say is deep learning + + align:start position:0% +what I want to say is deep learning + + + align:start position:0% +what I want to say is deep learning +neural Nets machine learning that the + + align:start position:0% +neural Nets machine learning that the + + + align:start position:0% +neural Nets machine learning that the +big computation is to minimize an energy + + align:start position:0% +big computation is to minimize an energy + + + align:start position:0% +big computation is to minimize an energy +is to minimize an energy now of course I + + align:start position:0% +is to minimize an energy now of course I + + + align:start position:0% +is to minimize an energy now of course I +made the minimum easy to find because I + + align:start position:0% +made the minimum easy to find because I + + + align:start position:0% +made the minimum easy to find because I +have pure squares + + align:start position:0% +have pure squares + + + align:start position:0% +have pure squares +well that doesn't happen in practice of + + align:start position:0% +well that doesn't happen in practice of + + + align:start position:0% +well that doesn't happen in practice of +course in practice we have linear terms + + align:start position:0% +course in practice we have linear terms + + + align:start position:0% +course in practice we have linear terms +X transpose B or nonlinear yeah the loss + + align:start position:0% +X transpose B or nonlinear yeah the loss + + + align:start position:0% +X transpose B or nonlinear yeah the loss +function doesn't have to be a thing + + align:start position:0% +function doesn't have to be a thing + + + align:start position:0% +function doesn't have to be a thing +cross-entropy all kinds of things there + + align:start position:0% +cross-entropy all kinds of things there + + + align:start position:0% +cross-entropy all kinds of things there +there's a whole dictionary of possible + + align:start position:0% +there's a whole dictionary of possible + + + align:start position:0% +there's a whole dictionary of possible +loss functions but but this is the model + + align:start position:0% +loss functions but but this is the model + + + align:start position:0% +loss functions but but this is the model +this is the model and I'll make it the + + align:start position:0% +this is the model and I'll make it the + + + align:start position:0% +this is the model and I'll make it the +perfect model by just focusing on that + + align:start position:0% +perfect model by just focusing on that + + + align:start position:0% +perfect model by just focusing on that +on that part well yeah by the way what + + align:start position:0% +on that part well yeah by the way what + + + align:start position:0% +on that part well yeah by the way what +what what would create what would happen + + align:start position:0% +what what would create what would happen + + + align:start position:0% +what what would create what would happen +if that was in there I shouldn't have + + align:start position:0% +if that was in there I shouldn't have + + + align:start position:0% +if that was in there I shouldn't have +exited out so so well so quickly since I + + align:start position:0% +exited out so so well so quickly since I + + + align:start position:0% +exited out so so well so quickly since I +just put it up there let me put it back + + align:start position:0% +just put it up there let me put it back + + + align:start position:0% +just put it up there let me put it back +up + + align:start position:0% +up + + + align:start position:0% +up +I saw it better rather okay + + align:start position:0% +I saw it better rather okay + + + align:start position:0% +I saw it better rather okay +this is the kind of least squares + + align:start position:0% +this is the kind of least squares + + + align:start position:0% +this is the kind of least squares +problem with some data be minimize that + + align:start position:0% +problem with some data be minimize that + + + align:start position:0% +problem with some data be minimize that +so what would be the graph of this guy + + align:start position:0% +so what would be the graph of this guy + + + align:start position:0% +so what would be the graph of this guy +can I just draw the same sort of picture + + align:start position:0% +can I just draw the same sort of picture + + + align:start position:0% +can I just draw the same sort of picture +for that function will it be a bowl yes + + align:start position:0% +for that function will it be a bowl yes + + + align:start position:0% +for that function will it be a bowl yes +if I have this term all that does is + + align:start position:0% +if I have this term all that does is + + + align:start position:0% +if I have this term all that does is +move it off center here at x equals 0 + + align:start position:0% +move it off center here at x equals 0 + + + align:start position:0% +move it off center here at x equals 0 +well I still get 0 sorry I still go + + align:start position:0% +well I still get 0 sorry I still go + + + align:start position:0% +well I still get 0 sorry I still go +through that point if this is the zero + + align:start position:0% +through that point if this is the zero + + + align:start position:0% +through that point if this is the zero +vector I'm still getting 0 but this will + + align:start position:0% +vector I'm still getting 0 but this will + + + align:start position:0% +vector I'm still getting 0 but this will +bring it below that would that would + + align:start position:0% +bring it below that would that would + + + align:start position:0% +bring it below that would that would +produce a bowl like that actually it + + align:start position:0% +produce a bowl like that actually it + + + align:start position:0% +produce a bowl like that actually it +would just be + + align:start position:0% +would just be + + + align:start position:0% +would just be +same Bowl the bowl is would just be + + align:start position:0% +same Bowl the bowl is would just be + + + align:start position:0% +same Bowl the bowl is would just be +shifted I could write that to show how + + align:start position:0% +shifted I could write that to show how + + + align:start position:0% +shifted I could write that to show how +that happens so this is this is now + + align:start position:0% +that happens so this is this is now + + + align:start position:0% +that happens so this is this is now +below zero this is the that's the + + align:start position:0% +below zero this is the that's the + + + align:start position:0% +below zero this is the that's the +solution we're after + + align:start position:0% +solution we're after + + + align:start position:0% +solution we're after +that tells us the weights in the neural + + align:start position:0% +that tells us the weights in the neural + + + align:start position:0% +that tells us the weights in the neural +network I'm just using these words but + + align:start position:0% +network I'm just using these words but + + + align:start position:0% +network I'm just using these words but +will soon have a meaning to them I want + + align:start position:0% +will soon have a meaning to them I want + + + align:start position:0% +will soon have a meaning to them I want +to find that minimum in other words and + + align:start position:0% +to find that minimum in other words and + + + align:start position:0% +to find that minimum in other words and +I want to find it for much more + + align:start position:0% +I want to find it for much more + + + align:start position:0% +I want to find it for much more +complicated functions than that of + + align:start position:0% +complicated functions than that of + + + align:start position:0% +complicated functions than that of +course if I minimize a quadratic that + + align:start position:0% +course if I minimize a quadratic that + + + align:start position:0% +course if I minimize a quadratic that +means setting derivatives to zero I just + + align:start position:0% +means setting derivatives to zero I just + + + align:start position:0% +means setting derivatives to zero I just +have linear equations probably I can I + + align:start position:0% +have linear equations probably I can I + + + align:start position:0% +have linear equations probably I can I +could write everything down for that for + + align:start position:0% +could write everything down for that for + + + align:start position:0% +could write everything down for that for +that thing so let's put in some + + align:start position:0% +that thing so let's put in some + + + align:start position:0% +that thing so let's put in some +nonlinear stuff which which wiggles the + + align:start position:0% +nonlinear stuff which which wiggles the + + + align:start position:0% +nonlinear stuff which which wiggles the +bowl makes it not so easy + + align:start position:0% + + + + align:start position:0% + +can I look a month ahead how do you find + + align:start position:0% +can I look a month ahead how do you find + + + align:start position:0% +can I look a month ahead how do you find +so this is a big part of mathematics + + align:start position:0% +so this is a big part of mathematics + + + align:start position:0% +so this is a big part of mathematics +applied math optimization minimization + + align:start position:0% +applied math optimization minimization + + + align:start position:0% +applied math optimization minimization +of a complicated function of a hundred + + align:start position:0% +of a complicated function of a hundred + + + align:start position:0% +of a complicated function of a hundred +thousand variables that's the biggest + + align:start position:0% +thousand variables that's the biggest + + + align:start position:0% +thousand variables that's the biggest +computation that's the reason machine + + align:start position:0% +computation that's the reason machine + + + align:start position:0% +computation that's the reason machine +learning on big problems takes a week on + + align:start position:0% +learning on big problems takes a week on + + + align:start position:0% +learning on big problems takes a week on +a GPU or multiple GPUs because you have + + align:start position:0% +a GPU or multiple GPUs because you have + + + align:start position:0% +a GPU or multiple GPUs because you have +so many unknowns more than 100000 would + + align:start position:0% +so many unknowns more than 100000 would + + + align:start position:0% +so many unknowns more than 100000 would +be quite normal in general let's just + + align:start position:0% +be quite normal in general let's just + + + align:start position:0% +be quite normal in general let's just +have the pleasure of looking ahead for + + align:start position:0% +have the pleasure of looking ahead for + + + align:start position:0% +have the pleasure of looking ahead for +one minute and then I'll come back to + + align:start position:0% +one minute and then I'll come back to + + + align:start position:0% +one minute and then I'll come back to +real life here linear algebra yeah just + + align:start position:0% +real life here linear algebra yeah just + + + align:start position:0% +real life here linear algebra yeah just +I can't resist thinking aloud how do you + + align:start position:0% +I can't resist thinking aloud how do you + + + align:start position:0% +I can't resist thinking aloud how do you +find the minimum by the way these + + align:start position:0% +find the minimum by the way these + + + align:start position:0% +find the minimum by the way these +functions both of them are convex so + + align:start position:0% +functions both of them are convex so + + + align:start position:0% +functions both of them are convex so +that is convex + + align:start position:0% + + + + align:start position:0% + +so I want to connect convex functions F + + align:start position:0% +so I want to connect convex functions F + + + align:start position:0% +so I want to connect convex functions F +and what does convex mean it means well + + align:start position:0% +and what does convex mean it means well + + + align:start position:0% +and what does convex mean it means well +that the graph is like that yeah I mean + + align:start position:0% +that the graph is like that yeah I mean + + + align:start position:0% +that the graph is like that yeah I mean +not perfect it could it could but if if + + align:start position:0% +not perfect it could it could but if if + + + align:start position:0% +not perfect it could it could but if if +it's a quadratic then convex means + + align:start position:0% +it's a quadratic then convex means + + + align:start position:0% +it's a quadratic then convex means +positive definite or maybe in the + + align:start position:0% +positive definite or maybe in the + + + align:start position:0% +positive definite or maybe in the +extreme positive semi-definite I'll have + + align:start position:0% +extreme positive semi-definite I'll have + + + align:start position:0% +extreme positive semi-definite I'll have +to mention that yeah but but convex + + align:start position:0% +to mention that yeah but but convex + + + align:start position:0% +to mention that yeah but but convex +means it goes up but it could have + + align:start position:0% +means it goes up but it could have + + + align:start position:0% +means it goes up but it could have +Wiggles it doesn't have to be just + + align:start position:0% +Wiggles it doesn't have to be just + + + align:start position:0% +Wiggles it doesn't have to be just +perfect squares and linear terms but + + align:start position:0% +perfect squares and linear terms but + + + align:start position:0% +perfect squares and linear terms but +general things and for for deep learning + + align:start position:0% +general things and for for deep learning + + + align:start position:0% +general things and for for deep learning +it will include none it'll go far beyond + + align:start position:0% +it will include none it'll go far beyond + + + align:start position:0% +it will include none it'll go far beyond +quadratics but well it may not be convex + + align:start position:0% +quadratics but well it may not be convex + + + align:start position:0% +quadratics but well it may not be convex +I guess that's also true yeah so so deep + + align:start position:0% +I guess that's also true yeah so so deep + + + align:start position:0% +I guess that's also true yeah so so deep +learning has got serious problems + + align:start position:0% +learning has got serious problems + + + align:start position:0% +learning has got serious problems +because those functions they may look + + align:start position:0% +because those functions they may look + + + align:start position:0% +because those functions they may look +like this but then over here they could + + align:start position:0% +like this but then over here they could + + + align:start position:0% +like this but then over here they could +go you know non convex they could dip + + align:start position:0% +go you know non convex they could dip + + + align:start position:0% +go you know non convex they could dip +down a little more and you're looking + + align:start position:0% +down a little more and you're looking + + + align:start position:0% +down a little more and you're looking +for this point or for this point still + + align:start position:0% +for this point or for this point still + + + align:start position:0% +for this point or for this point still +I'm determined to tell you how to find + + align:start position:0% +I'm determined to tell you how to find + + + align:start position:0% +I'm determined to tell you how to find +it so or a start on how you find it so + + align:start position:0% +it so or a start on how you find it so + + + align:start position:0% +it so or a start on how you find it so +you're at some point there right sorry + + align:start position:0% +you're at some point there right sorry + + + align:start position:0% +you're at some point there right sorry +start there somewhere on this surface + + align:start position:0% +start there somewhere on this surface + + + align:start position:0% +start there somewhere on this surface +some X some some vector X is your start + + align:start position:0% +some X some some vector X is your start + + + align:start position:0% +some X some some vector X is your start +x0 starting and we're going to just take + + align:start position:0% +x0 starting and we're going to just take + + + align:start position:0% +x0 starting and we're going to just take +a step hopefully down down the bowl well + + align:start position:0% +a step hopefully down down the bowl well + + + align:start position:0% +a step hopefully down down the bowl well +of course it would be fantastic to take + + align:start position:0% +of course it would be fantastic to take + + + align:start position:0% +of course it would be fantastic to take +to get there in one step but that's not + + align:start position:0% +to get there in one step but that's not + + + align:start position:0% +to get there in one step but that's not +going to happen that that would be + + align:start position:0% +going to happen that that would be + + + align:start position:0% +going to happen that that would be +solving a big linear system very + + align:start position:0% +solving a big linear system very + + + align:start position:0% +solving a big linear system very +expensive and a big nonlinear system so + + align:start position:0% +expensive and a big nonlinear system so + + + align:start position:0% +expensive and a big nonlinear system so +really that's what we're trying to solve + + align:start position:0% +really that's what we're trying to solve + + + align:start position:0% +really that's what we're trying to solve +a big nonlinear system and I should be + + align:start position:0% +a big nonlinear system and I should be + + + align:start position:0% +a big nonlinear system and I should be +like on this picture + + align:start position:0% +like on this picture + + + align:start position:0% +like on this picture +because here we can see where the + + align:start position:0% +because here we can see where the + + + align:start position:0% +because here we can see where the +minimum is but they just shift so what + + align:start position:0% +minimum is but they just shift so what + + + align:start position:0% +minimum is but they just shift so what +would you do if you had a starting point + + align:start position:0% +would you do if you had a starting point + + + align:start position:0% +would you do if you had a starting point +and you wanted to go look for the + + align:start position:0% +and you wanted to go look for the + + + align:start position:0% +and you wanted to go look for the +minimum but what's the natural idea + + align:start position:0% +minimum but what's the natural idea + + + align:start position:0% +minimum but what's the natural idea +compute derivatives + + align:start position:0% +compute derivatives + + + align:start position:0% +compute derivatives +you've got calculus on your side compute + + align:start position:0% +you've got calculus on your side compute + + + align:start position:0% +you've got calculus on your side compute +the first derivatives so the first + + align:start position:0% +the first derivatives so the first + + + align:start position:0% +the first derivatives so the first +derivatives with respect to X so so I + + align:start position:0% +derivatives with respect to X so so I + + + align:start position:0% +derivatives with respect to X so so I +would compute the derivative of F with + + align:start position:0% +would compute the derivative of F with + + + align:start position:0% +would compute the derivative of F with +respect to X and the derivative of F + + align:start position:0% +respect to X and the derivative of F + + + align:start position:0% +respect to X and the derivative of F +with respect to Y and hundred thousand + + align:start position:0% +with respect to Y and hundred thousand + + + align:start position:0% +with respect to Y and hundred thousand +more and that takes a little while and + + align:start position:0% +more and that takes a little while and + + + align:start position:0% +more and that takes a little while and +now I've got the derivatives what do I + + align:start position:0% +now I've got the derivatives what do I + + + align:start position:0% +now I've got the derivatives what do I +do I go that tells me the steepest + + align:start position:0% +do I go that tells me the steepest + + + align:start position:0% +do I go that tells me the steepest +direction that tells me at that point + + align:start position:0% +direction that tells me at that point + + + align:start position:0% +direction that tells me at that point +which way is fastest way down so I would + + align:start position:0% +which way is fastest way down so I would + + + align:start position:0% +which way is fastest way down so I would +follow I would do a gradient descent I + + align:start position:0% +follow I would do a gradient descent I + + + align:start position:0% +follow I would do a gradient descent I +would follow that gradient this is + + align:start position:0% +would follow that gradient this is + + + align:start position:0% +would follow that gradient this is +called the gradient all the first + + align:start position:0% +called the gradient all the first + + + align:start position:0% +called the gradient all the first +derivatives is called the gradient of F + + align:start position:0% +derivatives is called the gradient of F + + + align:start position:0% +derivatives is called the gradient of F +the gradient gradient vector it's a + + align:start position:0% +the gradient gradient vector it's a + + + align:start position:0% +the gradient gradient vector it's a +vector of course because F is a function + + align:start position:0% +vector of course because F is a function + + + align:start position:0% +vector of course because F is a function +of lots of variables I would start down + + align:start position:0% +of lots of variables I would start down + + + align:start position:0% +of lots of variables I would start down +in that direction and how far to go + + align:start position:0% +in that direction and how far to go + + + align:start position:0% +in that direction and how far to go +that's like the million dollar question + + align:start position:0% +that's like the million dollar question + + + align:start position:0% +that's like the million dollar question +in in deep learning as when it is it is + + align:start position:0% +in in deep learning as when it is it is + + + align:start position:0% +in in deep learning as when it is it is +it gonna hit zero nope it's not it's not + + align:start position:0% +it gonna hit zero nope it's not it's not + + + align:start position:0% +it gonna hit zero nope it's not it's not +and so you basically you go down until + + align:start position:0% +and so you basically you go down until + + + align:start position:0% +and so you basically you go down until +it until they go in so you're traveling + + align:start position:0% +it until they go in so you're traveling + + + align:start position:0% +it until they go in so you're traveling +here in the X along the gradient and + + align:start position:0% +here in the X along the gradient and + + + align:start position:0% +here in the X along the gradient and +you're you're not even you're not gonna + + align:start position:0% +you're you're not even you're not gonna + + + align:start position:0% +you're you're not even you're not gonna +hit zero you're right you're all going + + align:start position:0% +hit zero you're right you're all going + + + align:start position:0% +hit zero you're right you're all going +here in some direction and you want to + + align:start position:0% +here in some direction and you want to + + + align:start position:0% +here in some direction and you want to +go so you keep going down this thing + + align:start position:0% +go so you keep going down this thing + + + align:start position:0% +go so you keep going down this thing +until it oh my I'm not Rembrandt here + + align:start position:0% +until it oh my I'm not Rembrandt here + + + align:start position:0% +until it oh my I'm not Rembrandt here +I'm there your path down think of + + align:start position:0% +I'm there your path down think of + + + align:start position:0% +I'm there your path down think of +yourself on a mountain + + align:start position:0% +yourself on a mountain + + + align:start position:0% +yourself on a mountain +you're trying to go downhill so you take + + align:start position:0% +you're trying to go downhill so you take + + + align:start position:0% +you're trying to go downhill so you take +as fast as you can so you take the + + align:start position:0% +as fast as you can so you take the + + + align:start position:0% +as fast as you can so you take the +steepest route down until but but but + + align:start position:0% +steepest route down until but but but + + + align:start position:0% +steepest route down until but but but +you have blinkers on you just once you + + align:start position:0% +you have blinkers on you just once you + + + align:start position:0% +you have blinkers on you just once you +decided on a direction you go in that + + align:start position:0% +decided on a direction you go in that + + + align:start position:0% +decided on a direction you go in that +direction of course yeah so so what will + + align:start position:0% +direction of course yeah so so what will + + + align:start position:0% +direction of course yeah so so what will +happen you'll go down for a while and + + align:start position:0% +happen you'll go down for a while and + + + align:start position:0% +happen you'll go down for a while and +then it will turn up again right when + + align:start position:0% +then it will turn up again right when + + + align:start position:0% +then it will turn up again right when +you get sort of maybe close to the + + align:start position:0% +you get sort of maybe close to the + + + align:start position:0% +you get sort of maybe close to the +bottom or maybe not you you're not going + + align:start position:0% +bottom or maybe not you you're not going + + + align:start position:0% +bottom or maybe not you you're not going +to hit here and it's gonna miss that and + + align:start position:0% +to hit here and it's gonna miss that and + + + align:start position:0% +to hit here and it's gonna miss that and +come up maybe I should draw it over here + + align:start position:0% +come up maybe I should draw it over here + + + align:start position:0% +come up maybe I should draw it over here +whatever so this is it's called a line + + align:start position:0% +whatever so this is it's called a line + + + align:start position:0% +whatever so this is it's called a line +surge to decide how far to go there and + + align:start position:0% +surge to decide how far to go there and + + + align:start position:0% +surge to decide how far to go there and +then say okay stop and you can invest a + + align:start position:0% +then say okay stop and you can invest a + + + align:start position:0% +then say okay stop and you can invest a +lot of time or a little time to decide + + align:start position:0% +lot of time or a little time to decide + + + align:start position:0% +lot of time or a little time to decide +on that first stopping point and now + + align:start position:0% +on that first stopping point and now + + + align:start position:0% +on that first stopping point and now +just tell me what do you do next + + align:start position:0% +just tell me what do you do next + + + align:start position:0% +just tell me what do you do next +so now you're here what what now + + align:start position:0% +so now you're here what what now + + + align:start position:0% +so now you're here what what now +recalculate the gradient find the + + align:start position:0% +recalculate the gradient find the + + + align:start position:0% +recalculate the gradient find the +steepest way down from that point follow + + align:start position:0% +steepest way down from that point follow + + + align:start position:0% +steepest way down from that point follow +it until it turns up or approximately + + align:start position:0% +it until it turns up or approximately + + + align:start position:0% +it until it turns up or approximately +then you're at a new point so this is + + align:start position:0% +then you're at a new point so this is + + + align:start position:0% +then you're at a new point so this is +gradient descent + + align:start position:0% +gradient descent + + + align:start position:0% +gradient descent +that's a gradient descent the big + + align:start position:0% +that's a gradient descent the big + + + align:start position:0% +that's a gradient descent the big +algorithm of deep learning of neural + + align:start position:0% +algorithm of deep learning of neural + + + align:start position:0% +algorithm of deep learning of neural +Nets of machine learning great of + + align:start position:0% +Nets of machine learning great of + + + align:start position:0% +Nets of machine learning great of +optimization you could say notice that + + align:start position:0% +optimization you could say notice that + + + align:start position:0% +optimization you could say notice that +we didn't compute second derivatives if + + align:start position:0% +we didn't compute second derivatives if + + + align:start position:0% +we didn't compute second derivatives if +if we computed second derivatives we + + align:start position:0% +if we computed second derivatives we + + + align:start position:0% +if we computed second derivatives we +could have a fancier formula that could + + align:start position:0% +could have a fancier formula that could + + + align:start position:0% +could have a fancier formula that could +account for the bending the curve here + + align:start position:0% +account for the bending the curve here + + + align:start position:0% +account for the bending the curve here +but to compute second derivatives when + + align:start position:0% +but to compute second derivatives when + + + align:start position:0% +but to compute second derivatives when +you've got hundreds of thousands of + + align:start position:0% +you've got hundreds of thousands of + + + align:start position:0% +you've got hundreds of thousands of +variables is is not a lot of fun so most + + align:start position:0% +variables is is not a lot of fun so most + + + align:start position:0% +variables is is not a lot of fun so most +effectively machine learning is limited + + align:start position:0% +effectively machine learning is limited + + + align:start position:0% +effectively machine learning is limited +to first derivatives the gradient so + + align:start position:0% +to first derivatives the gradient so + + + align:start position:0% +to first derivatives the gradient so +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so that's the general idea but there are + + align:start position:0% +so that's the general idea but there are + + + align:start position:0% +so that's the general idea but there are +lots and lots of + + align:start position:0% + + + + align:start position:0% + +decisions and why doesn't that how well + + align:start position:0% +decisions and why doesn't that how well + + + align:start position:0% +decisions and why doesn't that how well +does that work + + align:start position:0% +does that work + + + align:start position:0% +does that work +maybe maybe is a good way to good + + align:start position:0% +maybe maybe is a good way to good + + + align:start position:0% +maybe maybe is a good way to good +question to ask does this work pretty + + align:start position:0% +question to ask does this work pretty + + + align:start position:0% +question to ask does this work pretty +well you know or do we have to add more + + align:start position:0% +well you know or do we have to add more + + + align:start position:0% +well you know or do we have to add more +ideas well it doesn't always work well + + align:start position:0% +ideas well it doesn't always work well + + + align:start position:0% +ideas well it doesn't always work well +let me tell you what the trouble is I + + align:start position:0% +let me tell you what the trouble is I + + + align:start position:0% +let me tell you what the trouble is I +don't so I'm Way off of like this is + + align:start position:0% +don't so I'm Way off of like this is + + + align:start position:0% +don't so I'm Way off of like this is +this is like March or something but + + align:start position:0% +this is like March or something but + + + align:start position:0% +this is like March or something but +anyway I'll finish the sentence so what + + align:start position:0% +anyway I'll finish the sentence so what + + + align:start position:0% +anyway I'll finish the sentence so what +what's the problem with this gradient + + align:start position:0% +what's the problem with this gradient + + + align:start position:0% +what's the problem with this gradient +descent idea it it turns out if you're + + align:start position:0% +descent idea it it turns out if you're + + + align:start position:0% +descent idea it it turns out if you're +going down a narrow Valley I don't know + + align:start position:0% +going down a narrow Valley I don't know + + + align:start position:0% +going down a narrow Valley I don't know +if you can sort of imagine a narrow + + align:start position:0% +if you can sort of imagine a narrow + + + align:start position:0% +if you can sort of imagine a narrow +valley toward the bottom so so here's + + align:start position:0% +valley toward the bottom so so here's + + + align:start position:0% +valley toward the bottom so so here's +here's the here's the bottom here's your + + align:start position:0% +here's the here's the bottom here's your + + + align:start position:0% +here's the here's the bottom here's your +starting point and this is so I mean you + + align:start position:0% +starting point and this is so I mean you + + + align:start position:0% +starting point and this is so I mean you +have to think of this as a bowl so the + + align:start position:0% +have to think of this as a bowl so the + + + align:start position:0% +have to think of this as a bowl so the +yeah the bowl is the were the two + + align:start position:0% +yeah the bowl is the were the two + + + align:start position:0% +yeah the bowl is the were the two +eigenvalues you could say are one and a + + align:start position:0% +eigenvalues you could say are one and a + + + align:start position:0% +eigenvalues you could say are one and a +very small number the bowl is long and + + align:start position:0% +very small number the bowl is long and + + + align:start position:0% +very small number the bowl is long and +thin are you with me + + align:start position:0% +thin are you with me + + + align:start position:0% +thin are you with me +imagine a long thin bowl then what + + align:start position:0% +imagine a long thin bowl then what + + + align:start position:0% +imagine a long thin bowl then what +happens for that case you you take + + align:start position:0% +happens for that case you you take + + + align:start position:0% +happens for that case you you take +steepest descent but you cross the + + align:start position:0% +steepest descent but you cross the + + + align:start position:0% +steepest descent but you cross the +valley and very soon you're climbing + + align:start position:0% +valley and very soon you're climbing + + + align:start position:0% +valley and very soon you're climbing +again so you take very it's very small + + align:start position:0% +again so you take very it's very small + + + align:start position:0% +again so you take very it's very small +steps just staggering back and forth + + align:start position:0% +steps just staggering back and forth + + + align:start position:0% +steps just staggering back and forth +across this and getting slowly but too + + align:start position:0% +across this and getting slowly but too + + + align:start position:0% +across this and getting slowly but too +slowly toward the bottom there so that's + + align:start position:0% +slowly toward the bottom there so that's + + + align:start position:0% +slowly toward the bottom there so that's +why things have got to be improved you + + align:start position:0% +why things have got to be improved you + + + align:start position:0% +why things have got to be improved you +can if you have I can value a very small + + align:start position:0% +can if you have I can value a very small + + + align:start position:0% +can if you have I can value a very small +eigenvalue in a very large eigenvalue + + align:start position:0% +eigenvalue in a very large eigenvalue + + + align:start position:0% +eigenvalue in a very large eigenvalue +those tell you the the shape of the bowl + + align:start position:0% +those tell you the the shape of the bowl + + + align:start position:0% +those tell you the the shape of the bowl +of course and many cases will will be + + align:start position:0% +of course and many cases will will be + + + align:start position:0% +of course and many cases will will be +like that have a small and a large I can + + align:start position:0% +like that have a small and a large I can + + + align:start position:0% +like that have a small and a large I can +value and then you're spending all your + + align:start position:0% +value and then you're spending all your + + + align:start position:0% +value and then you're spending all your +time + + align:start position:0% +time + + + align:start position:0% +time +you're quickly going up the other side + + align:start position:0% +you're quickly going up the other side + + + align:start position:0% +you're quickly going up the other side +down up down up down and you need a new + + align:start position:0% +down up down up down and you need a new + + + align:start position:0% +down up down up down and you need a new +idea okay so that's really so this is + + align:start position:0% +idea okay so that's really so this is + + + align:start position:0% +idea okay so that's really so this is +one major reason why positive-definite + + align:start position:0% +one major reason why positive-definite + + + align:start position:0% +one major reason why positive-definite +is so important because + + align:start position:0% +is so important because + + + align:start position:0% +is so important because +positive-definite gives pictures like + + align:start position:0% +positive-definite gives pictures like + + + align:start position:0% +positive-definite gives pictures like +that but then we have this question of + + align:start position:0% +that but then we have this question of + + + align:start position:0% +that but then we have this question of +are the eigenvalues sort of the same + + align:start position:0% +are the eigenvalues sort of the same + + + align:start position:0% +are the eigenvalues sort of the same +size of course if the eigenvalues are + + align:start position:0% +size of course if the eigenvalues are + + + align:start position:0% +size of course if the eigenvalues are +all equal what's my bowl like suppose we + + align:start position:0% +all equal what's my bowl like suppose we + + + align:start position:0% +all equal what's my bowl like suppose we +suppose all the suppose I have the + + align:start position:0% +suppose all the suppose I have the + + + align:start position:0% +suppose all the suppose I have the +identity so that's x squared plus y + + align:start position:0% +identity so that's x squared plus y + + + align:start position:0% +identity so that's x squared plus y +squared is my function then it's a + + align:start position:0% +squared is my function then it's a + + + align:start position:0% +squared is my function then it's a +perfectly circular Bowl what will happen + + align:start position:0% +perfectly circular Bowl what will happen + + + align:start position:0% +perfectly circular Bowl what will happen +if I can you imagine a perfectly + + align:start position:0% +if I can you imagine a perfectly + + + align:start position:0% +if I can you imagine a perfectly +circular like any any bowl in the + + align:start position:0% +circular like any any bowl in the + + + align:start position:0% +circular like any any bowl in the +kitchen is probably most likely circular + + align:start position:0% +kitchen is probably most likely circular + + + align:start position:0% +kitchen is probably most likely circular +and suppose I do gradient descent there + + align:start position:0% +and suppose I do gradient descent there + + + align:start position:0% +and suppose I do gradient descent there +I start at some point on this perfectly + + align:start position:0% +I start at some point on this perfectly + + + align:start position:0% +I start at some point on this perfectly +circular Bowl I start down and where do + + align:start position:0% +circular Bowl I start down and where do + + + align:start position:0% +circular Bowl I start down and where do +I stop in that case do I hit bottom I do + + align:start position:0% +I stop in that case do I hit bottom I do + + + align:start position:0% +I stop in that case do I hit bottom I do +by symmetry I'm gonna so so if I take x + + align:start position:0% +by symmetry I'm gonna so so if I take x + + + align:start position:0% +by symmetry I'm gonna so so if I take x +squared plus y squared as my function + + align:start position:0% +squared plus y squared as my function + + + align:start position:0% +squared plus y squared as my function +and I start somewhere I figure out the + + align:start position:0% +and I start somewhere I figure out the + + + align:start position:0% +and I start somewhere I figure out the +gradient yeah the answer is I'll go + + align:start position:0% +gradient yeah the answer is I'll go + + + align:start position:0% +gradient yeah the answer is I'll go +right through the center so really it's + + align:start position:0% +right through the center so really it's + + + align:start position:0% +right through the center so really it's +positive positive eigen values positive + + align:start position:0% +positive positive eigen values positive + + + align:start position:0% +positive positive eigen values positive +definite matrices give us a bowl but if + + align:start position:0% +definite matrices give us a bowl but if + + + align:start position:0% +definite matrices give us a bowl but if +the eigenvalues are far apart that's + + align:start position:0% +the eigenvalues are far apart that's + + + align:start position:0% +the eigenvalues are far apart that's +when we have problems ok I'm going back + + align:start position:0% +when we have problems ok I'm going back + + + align:start position:0% +when we have problems ok I'm going back +to my job which is this list because you + + align:start position:0% +to my job which is this list because you + + + align:start position:0% +to my job which is this list because you +really this is so nice + + align:start position:0% +really this is so nice + + + align:start position:0% +really this is so nice +yeah right could you + + align:start position:0% +yeah right could you + + + align:start position:0% +yeah right could you +well the homework that may be going out + + align:start position:0% +well the homework that may be going out + + + align:start position:0% +well the homework that may be going out +this minute for middle of next week + + align:start position:0% +this minute for middle of next week + + + align:start position:0% +this minute for middle of next week +gives you some exercises + + align:start position:0% +gives you some exercises + + + align:start position:0% +gives you some exercises +with this let me do a couple of things a + + align:start position:0% +with this let me do a couple of things a + + + align:start position:0% +with this let me do a couple of things a +couple of exercises here for example + + align:start position:0% +couple of exercises here for example + + + align:start position:0% +couple of exercises here for example +suppose I have a positive different + + align:start position:0% +suppose I have a positive different + + + align:start position:0% +suppose I have a positive different +matrix S and a positive definite matrix + + align:start position:0% +matrix S and a positive definite matrix + + + align:start position:0% +matrix S and a positive definite matrix +T if I add those matrices is a result + + align:start position:0% +T if I add those matrices is a result + + + align:start position:0% +T if I add those matrices is a result +positive definite so there's a perfect + + align:start position:0% +positive definite so there's a perfect + + + align:start position:0% +positive definite so there's a perfect +math question and we hope to answer so + + align:start position:0% +math question and we hope to answer so + + + align:start position:0% +math question and we hope to answer so +SMT positive definite what about s plus + + align:start position:0% +SMT positive definite what about s plus + + + align:start position:0% +SMT positive definite what about s plus +T is that matrix positive definite okay + + align:start position:0% +T is that matrix positive definite okay + + + align:start position:0% +T is that matrix positive definite okay +how do I answer such a question I look + + align:start position:0% +how do I answer such a question I look + + + align:start position:0% +how do I answer such a question I look +at my five tests and I think can I use + + align:start position:0% +at my five tests and I think can I use + + + align:start position:0% +at my five tests and I think can I use +it what which one will be good and the + + align:start position:0% +it what which one will be good and the + + + align:start position:0% +it what which one will be good and the +whoa and one that won't tell me much is + + align:start position:0% +whoa and one that won't tell me much is + + + align:start position:0% +whoa and one that won't tell me much is +the eigenvalues because the eigen values + + align:start position:0% +the eigenvalues because the eigen values + + + align:start position:0% +the eigenvalues because the eigen values +of s plus T are not immediately clear + + align:start position:0% +of s plus T are not immediately clear + + + align:start position:0% +of s plus T are not immediately clear +from the eigenvalues of s and T + + align:start position:0% +from the eigenvalues of s and T + + + align:start position:0% +from the eigenvalues of s and T +separately I don't want to use that test + + align:start position:0% +separately I don't want to use that test + + + align:start position:0% +separately I don't want to use that test +this is my favorite test so I'm going to + + align:start position:0% +this is my favorite test so I'm going to + + + align:start position:0% +this is my favorite test so I'm going to +use that what about the energy in so + + align:start position:0% +use that what about the energy in so + + + align:start position:0% +use that what about the energy in so +look at the energies so I look at X + + align:start position:0% +look at the energies so I look at X + + + align:start position:0% +look at the energies so I look at X +transpose s plus T X and what's my + + align:start position:0% +transpose s plus T X and what's my + + + align:start position:0% +transpose s plus T X and what's my +question in my mind here is that a + + align:start position:0% +question in my mind here is that a + + + align:start position:0% +question in my mind here is that a +positive number or not for every X and + + align:start position:0% +positive number or not for every X and + + + align:start position:0% +positive number or not for every X and +how am I going to answer that question + + align:start position:0% + + + + align:start position:0% + +just separate those two into two pieces + + align:start position:0% +just separate those two into two pieces + + + align:start position:0% +just separate those two into two pieces +right it's there in front of me it's + + align:start position:0% +right it's there in front of me it's + + + align:start position:0% +right it's there in front of me it's +this one what's this one and both of + + align:start position:0% +this one what's this one and both of + + + align:start position:0% +this one what's this one and both of +those are positive so the answer is yes + + align:start position:0% +those are positive so the answer is yes + + + align:start position:0% +those are positive so the answer is yes +it is positive definite yes + + align:start position:0% + + + + align:start position:0% + +you see how the energy just was right I + + align:start position:0% +you see how the energy just was right I + + + align:start position:0% +you see how the energy just was right I +don't want to compute the pivots or any + + align:start position:0% +don't want to compute the pivots or any + + + align:start position:0% +don't want to compute the pivots or any +determinants that would be like a + + align:start position:0% +determinants that would be like a + + + align:start position:0% +determinants that would be like a +nightmare trying to find determinants + + align:start position:0% +nightmare trying to find determinants + + + align:start position:0% +nightmare trying to find determinants +for s plus T but this one just doesn't + + align:start position:0% +for s plus T but this one just doesn't + + + align:start position:0% +for s plus T but this one just doesn't +immediately what else would be a good + + align:start position:0% +immediately what else would be a good + + + align:start position:0% +immediately what else would be a good +example to start with what about their + + align:start position:0% +example to start with what about their + + + align:start position:0% +example to start with what about their +sin verse is that positive definite yes + + align:start position:0% +sin verse is that positive definite yes + + + align:start position:0% +sin verse is that positive definite yes +positive definite and I want to ask + + align:start position:0% +positive definite and I want to ask + + + align:start position:0% +positive definite and I want to ask +about its inverse so int inverse is a + + align:start position:0% +about its inverse so int inverse is a + + + align:start position:0% +about its inverse so int inverse is a +symmetric matrix and is it positive + + align:start position:0% +symmetric matrix and is it positive + + + align:start position:0% +symmetric matrix and is it positive +definite and the answer yes yes I got + + align:start position:0% +definite and the answer yes yes I got + + + align:start position:0% +definite and the answer yes yes I got +five tests 20% chance of picking the + + align:start position:0% +five tests 20% chance of picking the + + + align:start position:0% +five tests 20% chance of picking the +right one determinants not good the + + align:start position:0% +right one determinants not good the + + + align:start position:0% +right one determinants not good the +first one is great + + align:start position:0% +first one is great + + + align:start position:0% +first one is great +the first one is the good one for this + + align:start position:0% +the first one is the good one for this + + + align:start position:0% +the first one is the good one for this +question because the eigen values so the + + align:start position:0% +question because the eigen values so the + + + align:start position:0% +question because the eigen values so the +answer is yes yes yes this is has eigen + + align:start position:0% +answer is yes yes yes this is has eigen + + + align:start position:0% +answer is yes yes yes this is has eigen +values so what are the eigenvalues of s + + align:start position:0% +values so what are the eigenvalues of s + + + align:start position:0% +values so what are the eigenvalues of s +inverse 1 over lambda so yes okay right + + align:start position:0% +inverse 1 over lambda so yes okay right + + + align:start position:0% +inverse 1 over lambda so yes okay right +yep + + align:start position:0% +yep + + + align:start position:0% +yep +what about yeah let me ask just one more + + align:start position:0% +what about yeah let me ask just one more + + + align:start position:0% +what about yeah let me ask just one more +question of this same sort suppose I + + align:start position:0% +question of this same sort suppose I + + + align:start position:0% +question of this same sort suppose I +have a matrix s and suppose I multiply + + align:start position:0% +have a matrix s and suppose I multiply + + + align:start position:0% +have a matrix s and suppose I multiply +it by another matrix oh well okay + + align:start position:0% +it by another matrix oh well okay + + + align:start position:0% +it by another matrix oh well okay +suppose yeah yep suppose I have suppose + + align:start position:0% +suppose yeah yep suppose I have suppose + + + align:start position:0% +suppose yeah yep suppose I have suppose +I asked you about s times another matrix + + align:start position:0% +I asked you about s times another matrix + + + align:start position:0% +I asked you about s times another matrix +M + + align:start position:0% + + + + align:start position:0% + +would that be positive definite or not + + align:start position:0% +would that be positive definite or not + + + align:start position:0% +would that be positive definite or not +now I'm gonna tell you the answer the + + align:start position:0% +now I'm gonna tell you the answer the + + + align:start position:0% +now I'm gonna tell you the answer the +answer is that the question wasn't any + + align:start position:0% +answer is that the question wasn't any + + + align:start position:0% +answer is that the question wasn't any +good because that matrix is probably not + + align:start position:0% +good because that matrix is probably not + + + align:start position:0% +good because that matrix is probably not +symmetric and I'm only dealing with + + align:start position:0% +symmetric and I'm only dealing with + + + align:start position:0% +symmetric and I'm only dealing with +symmetric matrices matrices have to be + + align:start position:0% +symmetric matrices matrices have to be + + + align:start position:0% +symmetric matrices matrices have to be +symmetric before I can before I know + + align:start position:0% +symmetric before I can before I know + + + align:start position:0% +symmetric before I can before I know +they have real eigenvalues and I can ask + + align:start position:0% +they have real eigenvalues and I can ask + + + align:start position:0% +they have real eigenvalues and I can ask +these questions so that's not good but I + + align:start position:0% +these questions so that's not good but I + + + align:start position:0% +these questions so that's not good but I +could oh let's see well let me hear ya + + align:start position:0% +could oh let's see well let me hear ya + + + align:start position:0% +could oh let's see well let me hear ya +let me let me put it in an orthogonal + + align:start position:0% +let me let me put it in an orthogonal + + + align:start position:0% +let me let me put it in an orthogonal +guy well they're still that's not + + align:start position:0% +guy well they're still that's not + + + align:start position:0% +guy well they're still that's not +symmetric but if I put C its transpose + + align:start position:0% +symmetric but if I put C its transpose + + + align:start position:0% +symmetric but if I put C its transpose +over there then I made it symmetric oh + + align:start position:0% +over there then I made it symmetric oh + + + align:start position:0% +over there then I made it symmetric oh +dear I may be getting myself in trouble + + align:start position:0% +dear I may be getting myself in trouble + + + align:start position:0% +dear I may be getting myself in trouble +here so I'm starting with a positive + + align:start position:0% +here so I'm starting with a positive + + + align:start position:0% +here so I'm starting with a positive +definite s I'm hitting with an + + align:start position:0% +definite s I'm hitting with an + + + align:start position:0% +definite s I'm hitting with an +orthogonal matrix and it's transpose and + + align:start position:0% +orthogonal matrix and it's transpose and + + + align:start position:0% +orthogonal matrix and it's transpose and +I sort of my instinct carried me here + + align:start position:0% +I sort of my instinct carried me here + + + align:start position:0% +I sort of my instinct carried me here +because I know that that's still + + align:start position:0% +because I know that that's still + + + align:start position:0% +because I know that that's still +symmetric right everybody sees that if I + + align:start position:0% +symmetric right everybody sees that if I + + + align:start position:0% +symmetric right everybody sees that if I +transpose this Q transpose will come + + align:start position:0% +transpose this Q transpose will come + + + align:start position:0% +transpose this Q transpose will come +here yes Q will go there it'll be some + + align:start position:0% +here yes Q will go there it'll be some + + + align:start position:0% +here yes Q will go there it'll be some +checks symmetric now is that positive + + align:start position:0% +checks symmetric now is that positive + + + align:start position:0% +checks symmetric now is that positive +definite oh yes we can't answer that can + + align:start position:0% +definite oh yes we can't answer that can + + + align:start position:0% +definite oh yes we can't answer that can +we + + align:start position:0% +we + + + align:start position:0% +we +is that positive definite so remember + + align:start position:0% +is that positive definite so remember + + + align:start position:0% +is that positive definite so remember +that this is an orthogonal matrix so I'm + + align:start position:0% +that this is an orthogonal matrix so I'm + + + align:start position:0% +that this is an orthogonal matrix so I'm +also if you wanted me to write it that + + align:start position:0% +also if you wanted me to write it that + + + align:start position:0% +also if you wanted me to write it that +way I could + + align:start position:0% +way I could + + + align:start position:0% +way I could +and what about positive definiteness of + + align:start position:0% +and what about positive definiteness of + + + align:start position:0% +and what about positive definiteness of +that thing the answer I think is yes do + + align:start position:0% +that thing the answer I think is yes do + + + align:start position:0% +that thing the answer I think is yes do +you agree it is positive definite give + + align:start position:0% +you agree it is positive definite give + + + align:start position:0% +you agree it is positive definite give +me a reason though why is this positive + + align:start position:0% +me a reason though why is this positive + + + align:start position:0% +me a reason though why is this positive +definite big so that word similar so + + align:start position:0% +definite big so that word similar so + + + align:start position:0% +definite big so that word similar so +what this is a similar matrix to S do + + align:start position:0% +what this is a similar matrix to S do + + + align:start position:0% +what this is a similar matrix to S do +you remember what similar means from + + align:start position:0% +you remember what similar means from + + + align:start position:0% +you remember what similar means from +last time it means that some m and its + + align:start position:0% +last time it means that some m and its + + + align:start position:0% +last time it means that some m and its +inverse or here we + + align:start position:0% +inverse or here we + + + align:start position:0% +inverse or here we +they are and so what's the what's the + + align:start position:0% +they are and so what's the what's the + + + align:start position:0% +they are and so what's the what's the +consequence of being similar what do I + + align:start position:0% +consequence of being similar what do I + + + align:start position:0% +consequence of being similar what do I +know about a matrix that's similar to s + + align:start position:0% +know about a matrix that's similar to s + + + align:start position:0% +know about a matrix that's similar to s +it has the same eigenvalues and + + align:start position:0% +it has the same eigenvalues and + + + align:start position:0% +it has the same eigenvalues and +therefore we're good right or I could go + + align:start position:0% +therefore we're good right or I could go + + + align:start position:0% +therefore we're good right or I could go +this way I could energy I like energy so + + align:start position:0% +this way I could energy I like energy so + + + align:start position:0% +this way I could energy I like energy so +let me try that one X transpose Q + + align:start position:0% +let me try that one X transpose Q + + + align:start position:0% +let me try that one X transpose Q +transpose su X that would be the energy + + align:start position:0% +transpose su X that would be the energy + + + align:start position:0% +transpose su X that would be the energy +and what am I trying to show I'm trying + + align:start position:0% +and what am I trying to show I'm trying + + + align:start position:0% +and what am I trying to show I'm trying +to show it's positive so of course my as + + align:start position:0% +to show it's positive so of course my as + + + align:start position:0% +to show it's positive so of course my as +soon as I see that like just waiting for + + align:start position:0% +soon as I see that like just waiting for + + + align:start position:0% +soon as I see that like just waiting for +me to the QX be something called Y maybe + + align:start position:0% +me to the QX be something called Y maybe + + + align:start position:0% +me to the QX be something called Y maybe +and then what will this be my Y + + align:start position:0% +and then what will this be my Y + + + align:start position:0% +and then what will this be my Y +transpose so this this energy would be + + align:start position:0% +transpose so this this energy would be + + + align:start position:0% +transpose so this this energy would be +the same as Y transpose s Y and what do + + align:start position:0% +the same as Y transpose s Y and what do + + + align:start position:0% +the same as Y transpose s Y and what do +I know about that it's positive because + + align:start position:0% +I know about that it's positive because + + + align:start position:0% +I know about that it's positive because +that's an energy in the Y for the Y + + align:start position:0% +that's an energy in the Y for the Y + + + align:start position:0% +that's an energy in the Y for the Y +vector so one way or another we get the + + align:start position:0% +vector so one way or another we get the + + + align:start position:0% +vector so one way or another we get the +answer yes to that question ok ok let me + + align:start position:0% + + + + align:start position:0% + +introduce the idea of semi-definite + + align:start position:0% +introduce the idea of semi-definite + + + align:start position:0% +introduce the idea of semi-definite +semi-definite is the borderline so so + + align:start position:0% +semi-definite is the borderline so so + + + align:start position:0% +semi-definite is the borderline so so +what did we have we had three four four + + align:start position:0% +what did we have we had three four four + + + align:start position:0% +what did we have we had three four four +and then when it was five you told me + + align:start position:0% +and then when it was five you told me + + + align:start position:0% +and then when it was five you told me +indefinite and negative eigenvalue when + + align:start position:0% +indefinite and negative eigenvalue when + + + align:start position:0% +indefinite and negative eigenvalue when +it was six you told me two positive + + align:start position:0% +it was six you told me two positive + + + align:start position:0% +it was six you told me two positive +eigenvalues definite what's the + + align:start position:0% +eigenvalues definite what's the + + + align:start position:0% +eigenvalues definite what's the +borderline + + align:start position:0% +borderline + + + align:start position:0% +borderline +what's the borderline there it's not + + align:start position:0% +what's the borderline there it's not + + + align:start position:0% +what's the borderline there it's not +it's not going to be an integer but it's + + align:start position:0% +it's not going to be an integer but it's + + + align:start position:0% +it's not going to be an integer but it's +well what do I mean what am I looking + + align:start position:0% +well what do I mean what am I looking + + + align:start position:0% +well what do I mean what am I looking +for it the borderline well yeah so tell + + align:start position:0% +for it the borderline well yeah so tell + + + align:start position:0% +for it the borderline well yeah so tell +me again sixteen over three that sounds + + align:start position:0% +me again sixteen over three that sounds + + + align:start position:0% +me again sixteen over three that sounds +right why is that the borderline because + + align:start position:0% +right why is that the borderline because + + + align:start position:0% +right why is that the borderline because +now the determinant is zero its singular + + align:start position:0% +now the determinant is zero its singular + + + align:start position:0% +now the determinant is zero its singular +it has a zero eigenvalue there's a zero + + align:start position:0% +it has a zero eigenvalue there's a zero + + + align:start position:0% +it has a zero eigenvalue there's a zero +eigenvalue so that's what semi definite + + align:start position:0% +eigenvalue so that's what semi definite + + + align:start position:0% +eigenvalue so that's what semi definite +means lambdas are greater equal to zero + + align:start position:0% +means lambdas are greater equal to zero + + + align:start position:0% +means lambdas are greater equal to zero +wait a minute that has a zero eigenvalue + + align:start position:0% +wait a minute that has a zero eigenvalue + + + align:start position:0% +wait a minute that has a zero eigenvalue +because it's determinant is zero how do + + align:start position:0% +because it's determinant is zero how do + + + align:start position:0% +because it's determinant is zero how do +i know that the other eigenvalue is + + align:start position:0% +i know that the other eigenvalue is + + + align:start position:0% +i know that the other eigenvalue is +positive could could the could it be + + align:start position:0% +positive could could the could it be + + + align:start position:0% +positive could could the could it be +that the other right so this is the semi + + align:start position:0% +that the other right so this is the semi + + + align:start position:0% +that the other right so this is the semi +definite case we hope but we better + + align:start position:0% +definite case we hope but we better + + + align:start position:0% +definite case we hope but we better +finish that reasoning how do I know that + + align:start position:0% +finish that reasoning how do I know that + + + align:start position:0% +finish that reasoning how do I know that +the other eigenvalue is positive the + + align:start position:0% +the other eigenvalue is positive the + + + align:start position:0% +the other eigenvalue is positive the +trace because the adding 3 plus 16 over + + align:start position:0% +trace because the adding 3 plus 16 over + + + align:start position:0% +trace because the adding 3 plus 16 over +3 whatever the heck that might give it + + align:start position:0% +3 whatever the heck that might give it + + + align:start position:0% +3 whatever the heck that might give it +certainly gives a positive number and + + align:start position:0% +certainly gives a positive number and + + + align:start position:0% +certainly gives a positive number and +that will be lambda 1 plus lambda 2 + + align:start position:0% +that will be lambda 1 plus lambda 2 + + + align:start position:0% +that will be lambda 1 plus lambda 2 +that's the trace but lambda 2 is 0 we + + align:start position:0% +that's the trace but lambda 2 is 0 we + + + align:start position:0% +that's the trace but lambda 2 is 0 we +know from this it's singular so we know + + align:start position:0% +know from this it's singular so we know + + + align:start position:0% +know from this it's singular so we know +where lambda 2 is 0 so lambda 1 must be + + align:start position:0% +where lambda 2 is 0 so lambda 1 must be + + + align:start position:0% +where lambda 2 is 0 so lambda 1 must be +3 plus 5 5 in a service lambda the + + align:start position:0% +3 plus 5 5 in a service lambda the + + + align:start position:0% +3 plus 5 5 in a service lambda the +lambdas must be 8 Messrs 3 plus 5 and + + align:start position:0% +lambdas must be 8 Messrs 3 plus 5 and + + + align:start position:0% +lambdas must be 8 Messrs 3 plus 5 and +1/3 and so that's a positive + + align:start position:0% +1/3 and so that's a positive + + + align:start position:0% +1/3 and so that's a positive +semi-definite oh if you think of the + + align:start position:0% +semi-definite oh if you think of the + + + align:start position:0% +semi-definite oh if you think of the +positive definite matrices as some clump + + align:start position:0% +positive definite matrices as some clump + + + align:start position:0% +positive definite matrices as some clump +in matrix space then the positive + + align:start position:0% +in matrix space then the positive + + + align:start position:0% +in matrix space then the positive +semi-definite ones are sort of the edge + + align:start position:0% +semi-definite ones are sort of the edge + + + align:start position:0% +semi-definite ones are sort of the edge +of that clump they're the boundary of + + align:start position:0% +of that clump they're the boundary of + + + align:start position:0% +of that clump they're the boundary of +the clump the ones that are not quite + + align:start position:0% +the clump the ones that are not quite + + + align:start position:0% +the clump the ones that are not quite +inside but not outside either there + + align:start position:0% +inside but not outside either there + + + align:start position:0% +inside but not outside either there +they're lying right on the edge of + + align:start position:0% +they're lying right on the edge of + + + align:start position:0% +they're lying right on the edge of +positive definite matrices let me just + + align:start position:0% +positive definite matrices let me just + + + align:start position:0% +positive definite matrices let me just +take a so what about what about a matrix + + align:start position:0% +take a so what about what about a matrix + + + align:start position:0% +take a so what about what about a matrix +of all ones what's the what's the story + + align:start position:0% +of all ones what's the what's the story + + + align:start position:0% +of all ones what's the what's the story +on that one positive definite all the + + align:start position:0% +on that one positive definite all the + + + align:start position:0% +on that one positive definite all the +numbers are positive or positive semi + + align:start position:0% +numbers are positive or positive semi + + + align:start position:0% +numbers are positive or positive semi +definite or indefinite what do you think + + align:start position:0% +definite or indefinite what do you think + + + align:start position:0% +definite or indefinite what do you think +here one more all one's semi definite + + align:start position:0% +here one more all one's semi definite + + + align:start position:0% +here one more all one's semi definite +sounds like a good guess + + align:start position:0% +sounds like a good guess + + + align:start position:0% +sounds like a good guess +you know what the eigenvalues of this + + align:start position:0% +you know what the eigenvalues of this + + + align:start position:0% +you know what the eigenvalues of this +matrix would be 3 0 & 0 why did you say + + align:start position:0% +matrix would be 3 0 & 0 why did you say + + + align:start position:0% +matrix would be 3 0 & 0 why did you say +that because we only have the rank is + + align:start position:0% +that because we only have the rank is + + + align:start position:0% +that because we only have the rank is +yeah introduce that key where the rank + + align:start position:0% +yeah introduce that key where the rank + + + align:start position:0% +yeah introduce that key where the rank +is 1 so there's only one nonzero eigen + + align:start position:0% +is 1 so there's only one nonzero eigen + + + align:start position:0% +is 1 so there's only one nonzero eigen +value and then the trace tells me it's + + align:start position:0% +value and then the trace tells me it's + + + align:start position:0% +value and then the trace tells me it's +that that number is 3 so this is a + + align:start position:0% +that that number is 3 so this is a + + + align:start position:0% +that that number is 3 so this is a +positive positive semi definite matrix + + align:start position:0% +positive positive semi definite matrix + + + align:start position:0% +positive positive semi definite matrix +so so all these all these tests change a + + align:start position:0% +so so all these all these tests change a + + + align:start position:0% +so so all these all these tests change a +little for semi definite the eigenvalue + + align:start position:0% +little for semi definite the eigenvalue + + + align:start position:0% +little for semi definite the eigenvalue +is greater or equal the energies greater + + align:start position:0% +is greater or equal the energies greater + + + align:start position:0% +is greater or equal the energies greater +or equal to 0 the a transpose a but now + + align:start position:0% +or equal to 0 the a transpose a but now + + + align:start position:0% +or equal to 0 the a transpose a but now +I don't require oh I didn't discuss this + + align:start position:0% +I don't require oh I didn't discuss this + + + align:start position:0% +I don't require oh I didn't discuss this +but but semi definite would allow + + align:start position:0% +but but semi definite would allow + + + align:start position:0% +but but semi definite would allow +dependent columns by the way + + align:start position:0% +dependent columns by the way + + + align:start position:0% +dependent columns by the way +you got to do this for me right that + + align:start position:0% +you got to do this for me right that + + + align:start position:0% +you got to do this for me right that +matrix as a transpose times a just to + + align:start position:0% +matrix as a transpose times a just to + + + align:start position:0% +matrix as a transpose times a just to +see that it's semi definite because so + + align:start position:0% +see that it's semi definite because so + + + align:start position:0% +see that it's semi definite because so +write that as a transpose a yeah if it's + + align:start position:0% +write that as a transpose a yeah if it's + + + align:start position:0% +write that as a transpose a yeah if it's +a rank one matrix you know how to what + + align:start position:0% +a rank one matrix you know how to what + + + align:start position:0% +a rank one matrix you know how to what +it must look like a transfer was a how + + align:start position:0% +it must look like a transfer was a how + + + align:start position:0% +it must look like a transfer was a how +many terms am I going to have in in this + + align:start position:0% +many terms am I going to have in in this + + + align:start position:0% +many terms am I going to have in in this +and now I'm thinking back to the very + + align:start position:0% +and now I'm thinking back to the very + + + align:start position:0% +and now I'm thinking back to the very +beginning of this course if I pulled off + + align:start position:0% +beginning of this course if I pulled off + + + align:start position:0% +beginning of this course if I pulled off +the pieces in general this is lambda one + + align:start position:0% +the pieces in general this is lambda one + + + align:start position:0% +the pieces in general this is lambda one +times the first eigenvector times the + + align:start position:0% +times the first eigenvector times the + + + align:start position:0% +times the first eigenvector times the +first eigenvector transpose yeah would + + align:start position:0% +first eigenvector transpose yeah would + + + align:start position:0% +first eigenvector transpose yeah would +just be a vector of three ones yeah so + + align:start position:0% +just be a vector of three ones yeah so + + + align:start position:0% +just be a vector of three ones yeah so +so this would be the usual picture that + + align:start position:0% +so this would be the usual picture that + + + align:start position:0% +so this would be the usual picture that +this is the same as the Q lambda Q + + align:start position:0% +this is the same as the Q lambda Q + + + align:start position:0% +this is the same as the Q lambda Q +transpose this is this is the big big + + align:start position:0% +transpose this is this is the big big + + + align:start position:0% +transpose this is this is the big big +fact for any symmetric matrix and this + + align:start position:0% +fact for any symmetric matrix and this + + + align:start position:0% +fact for any symmetric matrix and this +is symmetric but its rank is only one so + + align:start position:0% +is symmetric but its rank is only one so + + + align:start position:0% +is symmetric but its rank is only one so +that so that lambda two is zero for that + + align:start position:0% +that so that lambda two is zero for that + + + align:start position:0% +that so that lambda two is zero for that +matrix lambda 3 is zero for that matrix + + align:start position:0% +matrix lambda 3 is zero for that matrix + + + align:start position:0% +matrix lambda 3 is zero for that matrix +and and the one eigen vector is the + + align:start position:0% +and and the one eigen vector is the + + + align:start position:0% +and and the one eigen vector is the +vector 1 1 1 and the eigen so this would + + align:start position:0% +vector 1 1 1 and the eigen so this would + + + align:start position:0% +vector 1 1 1 and the eigen so this would +be 3 times 1 1 1 oh I have to do yeah so + + align:start position:0% +be 3 times 1 1 1 oh I have to do yeah so + + + align:start position:0% +be 3 times 1 1 1 oh I have to do yeah so +I was going to do 3 times 1 1 1 times 1 + + align:start position:0% +I was going to do 3 times 1 1 1 times 1 + + + align:start position:0% +I was going to do 3 times 1 1 1 times 1 +1 1 but that gives me 3 3 3 that's not + + align:start position:0% +1 1 but that gives me 3 3 3 that's not + + + align:start position:0% +1 1 but that gives me 3 3 3 that's not +right I have to normalize them that's + + align:start position:0% +right I have to normalize them that's + + + align:start position:0% +right I have to normalize them that's +right + + align:start position:0% +right + + + align:start position:0% +right +yeah so that's a vector of whose length + + align:start position:0% +yeah so that's a vector of whose length + + + align:start position:0% +yeah so that's a vector of whose length +is square root of 3 so I have to divide + + align:start position:0% +is square root of 3 so I have to divide + + + align:start position:0% +is square root of 3 so I have to divide +by that divide by it and then the 3 + + align:start position:0% +by that divide by it and then the 3 + + + align:start position:0% +by that divide by it and then the 3 +cancels the square root of threes and + + align:start position:0% +cancels the square root of threes and + + + align:start position:0% +cancels the square root of threes and +I'm just left with the 1 1 1 1 1 1 + + align:start position:0% + + + + align:start position:0% + +so there is a matrix one of our building + + align:start position:0% +so there is a matrix one of our building + + + align:start position:0% +so there is a matrix one of our building +block type matrices because it only has + + align:start position:0% +block type matrices because it only has + + + align:start position:0% +block type matrices because it only has +one nonzero eigen value it's rank is 1 + + align:start position:0% +one nonzero eigen value it's rank is 1 + + + align:start position:0% +one nonzero eigen value it's rank is 1 +so it could not be positive definite + + align:start position:0% +so it could not be positive definite + + + align:start position:0% +so it could not be positive definite +it's it's singular but it is positive + + align:start position:0% +it's it's singular but it is positive + + + align:start position:0% +it's it's singular but it is positive +semi definite because that eigen value + + align:start position:0% +semi definite because that eigen value + + + align:start position:0% +semi definite because that eigen value +is positive okay + + align:start position:0% +is positive okay + + + align:start position:0% +is positive okay +so you got the idea of positive definite + + align:start position:0% +so you got the idea of positive definite + + + align:start position:0% +so you got the idea of positive definite +matrices again all five of those any one + + align:start position:0% +matrices again all five of those any one + + + align:start position:0% +matrices again all five of those any one +of those five tests is enough to show + + align:start position:0% +of those five tests is enough to show + + + align:start position:0% +of those five tests is enough to show +that it's positive definite and so + + align:start position:0% +that it's positive definite and so + + + align:start position:0% +that it's positive definite and so +what's my goal next week is the singular + + align:start position:0% +what's my goal next week is the singular + + + align:start position:0% +what's my goal next week is the singular +value decomposition and all that that + + align:start position:0% +value decomposition and all that that + + + align:start position:0% +value decomposition and all that that +leads us to that's that's where we're + + align:start position:0% +leads us to that's that's where we're + + + align:start position:0% +leads us to that's that's where we're +there now ready for at the SVD okay have + + align:start position:0% +there now ready for at the SVD okay have + + + align:start position:0% +there now ready for at the SVD okay have +a good weekend and see ya oh I see you + + align:start position:0% +a good weekend and see ya oh I see you + + + align:start position:0% +a good weekend and see ya oh I see you +on Tuesday I guess right not Monday but + + align:start position:0% +on Tuesday I guess right not Monday but + + + align:start position:0% +on Tuesday I guess right not Monday but +Tuesday next week \ No newline at end of file diff --git a/xx8fH-r3Luk.txt b/xx8fH-r3Luk.txt new file mode 100644 index 0000000000000000000000000000000000000000..bc0e0bc7d5dfe18b67fab7fdd37c93306e12035b --- /dev/null +++ b/xx8fH-r3Luk.txt @@ -0,0 +1,522 @@ +align:start position:0% + +Kulom's force law can be the basis for + + align:start position:0% +Kulom's force law can be the basis for + + + align:start position:0% +Kulom's force law can be the basis for +estimating the net charge on an + + align:start position:0% +estimating the net charge on an + + + align:start position:0% +estimating the net charge on an +object. Conservation of charge and + + align:start position:0% +object. Conservation of charge and + + + align:start position:0% +object. Conservation of charge and +Gaus's law are also the basis for the + + align:start position:0% +Gaus's law are also the basis for the + + + align:start position:0% +Gaus's law are also the basis for the +measurement of + + align:start position:0% + + + + align:start position:0% + +charge. In this demonstration, the + + align:start position:0% +charge. In this demonstration, the + + + align:start position:0% +charge. In this demonstration, the +particles are air filled + + align:start position:0% +particles are air filled + + + align:start position:0% +particles are air filled +balloons of the variety used at parties. + + align:start position:0% + + + + align:start position:0% + +They can be charged by rubbing them with + + align:start position:0% +They can be charged by rubbing them with + + + align:start position:0% +They can be charged by rubbing them with +a dry cloth. + + align:start position:0% + + + + align:start position:0% + +They repel each other because they've + + align:start position:0% +They repel each other because they've + + + align:start position:0% +They repel each other because they've +been charged to the same + + align:start position:0% + + + + align:start position:0% + +polarity. Let's use measurements of the + + align:start position:0% +polarity. Let's use measurements of the + + + align:start position:0% +polarity. Let's use measurements of the +separation distance and the weight of + + align:start position:0% +separation distance and the weight of + + + align:start position:0% +separation distance and the weight of +the balloon to approximate the charge + + align:start position:0% +the balloon to approximate the charge + + + align:start position:0% +the balloon to approximate the charge +that's been left on one of the + + align:start position:0% +that's been left on one of the + + + align:start position:0% +that's been left on one of the +balloons. The threads that have been + + align:start position:0% +balloons. The threads that have been + + + align:start position:0% +balloons. The threads that have been +used to suspend them are tied at a + + align:start position:0% +used to suspend them are tied at a + + + align:start position:0% +used to suspend them are tied at a +common point. + + align:start position:0% + + + + align:start position:0% + +The spacing between balloon centers is + + align:start position:0% +The spacing between balloon centers is + + + align:start position:0% +The spacing between balloon centers is +about 50 cm. It's not possible to put + + align:start position:0% +about 50 cm. It's not possible to put + + + align:start position:0% +about 50 cm. It's not possible to put +the meter stick close to the balloons + + align:start position:0% +the meter stick close to the balloons + + + align:start position:0% +the meter stick close to the balloons +without their being attracted to + + align:start position:0% +without their being attracted to + + + align:start position:0% +without their being attracted to +Professor Zan. His body's a good + + align:start position:0% +Professor Zan. His body's a good + + + align:start position:0% +Professor Zan. His body's a good +conductor. The charges on the balloons + + align:start position:0% +conductor. The charges on the balloons + + + align:start position:0% +conductor. The charges on the balloons +induce image charges of opposite + + align:start position:0% +induce image charges of opposite + + + align:start position:0% +induce image charges of opposite +polarity on conducting surfaces to which + + align:start position:0% +polarity on conducting surfaces to which + + + align:start position:0% +polarity on conducting surfaces to which +they're attracted. + + align:start position:0% + + + + align:start position:0% + +This image charge is just that + + align:start position:0% +This image charge is just that + + + align:start position:0% +This image charge is just that +responsible for attracting the balloons + + align:start position:0% +responsible for attracting the balloons + + + align:start position:0% +responsible for attracting the balloons +to any essentially grounded conductor in + + align:start position:0% +to any essentially grounded conductor in + + + align:start position:0% +to any essentially grounded conductor in +its + + align:start position:0% + + + + align:start position:0% + +vicinity. By now, one of our balloons is + + align:start position:0% +vicinity. By now, one of our balloons is + + + align:start position:0% +vicinity. By now, one of our balloons is +broken. But with new balloons and a + + align:start position:0% +broken. But with new balloons and a + + + align:start position:0% +broken. But with new balloons and a +renewed charge, the spacing looks to be + + align:start position:0% +renewed charge, the spacing looks to be + + + align:start position:0% +renewed charge, the spacing looks to be +about what we had before. + + align:start position:0% +about what we had before. + + + align:start position:0% +about what we had before. +Here's what happens when we insert the + + align:start position:0% +Here's what happens when we insert the + + + align:start position:0% +Here's what happens when we insert the +balloon in the Faraday + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +cage. Watch the meter + + align:start position:0% + + + + align:start position:0% + +too. Our charge conservation statement + + align:start position:0% +too. Our charge conservation statement + + + align:start position:0% +too. Our charge conservation statement +can be used to see that it makes no + + align:start position:0% +can be used to see that it makes no + + + align:start position:0% +can be used to see that it makes no +difference to the measurement whether + + align:start position:0% +difference to the measurement whether + + + align:start position:0% +difference to the measurement whether +the balloon makes physical and + + align:start position:0% +the balloon makes physical and + + + align:start position:0% +the balloon makes physical and +electrical contact with the inner + + align:start position:0% +electrical contact with the inner + + + align:start position:0% +electrical contact with the inner +box. From the dial settings on the top + + align:start position:0% +box. From the dial settings on the top + + + align:start position:0% +box. From the dial settings on the top +scale, a full scale deflection is a + + align:start position:0% +scale, a full scale deflection is a + + + align:start position:0% +scale, a full scale deflection is a +charge of minus 1,000 + + align:start position:0% +charge of minus 1,000 + + + align:start position:0% +charge of minus 1,000 +nanolms. The measured charge is 220 or + + align:start position:0% +nanolms. The measured charge is 220 or + + + align:start position:0% +nanolms. The measured charge is 220 or + + align:start position:0% + + + + align:start position:0% + +nano. Let's see what we get for the + + align:start position:0% +nano. Let's see what we get for the + + + align:start position:0% +nano. Let's see what we get for the +other balloon. + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% + + + + align:start position:0% + +The reading is about the same about 220 + + align:start position:0% + + + + align:start position:0% + +nanoculum. When the balloon is removed, + + align:start position:0% +nanoculum. When the balloon is removed, + + + align:start position:0% +nanoculum. When the balloon is removed, +the meter reading almost goes back to + + align:start position:0% + + + + align:start position:0% + +zero. Apparently, the charge is + + align:start position:0% +zero. Apparently, the charge is + + + align:start position:0% +zero. Apparently, the charge is +essentially removed with the balloon. + + align:start position:0% + + + + align:start position:0% + +What happens to the charge on the + + align:start position:0% +What happens to the charge on the + + + align:start position:0% +What happens to the charge on the +balloon if it's broken while in the + + align:start position:0% +balloon if it's broken while in the + + + align:start position:0% +balloon if it's broken while in the +Faraday cage and then + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% + + + + align:start position:0% + +removed? We've used scotch tape to hold + + align:start position:0% +removed? We've used scotch tape to hold + + + align:start position:0% +removed? We've used scotch tape to hold +the balloon together. + + align:start position:0% + + + + align:start position:0% + +Professor Zhan feels that most of the + + align:start position:0% +Professor Zhan feels that most of the + + + align:start position:0% +Professor Zhan feels that most of the +balloon was removed. The charge was not. \ No newline at end of file diff --git a/yGvxqV-qpQ8.txt b/yGvxqV-qpQ8.txt new file mode 100644 index 0000000000000000000000000000000000000000..6848b621d87ac6ec9a6b17ed30796b30b72ac75a --- /dev/null +++ b/yGvxqV-qpQ8.txt @@ -0,0 +1,1267 @@ +align:start position:0% + +Welcome to the second week of our class + + align:start position:0% +Welcome to the second week of our class + + + align:start position:0% +Welcome to the second week of our class +on shaping the future of work. We got + + align:start position:0% +on shaping the future of work. We got + + + align:start position:0% +on shaping the future of work. We got +off to a great start last week with lots + + align:start position:0% +off to a great start last week with lots + + + align:start position:0% +off to a great start last week with lots +of good discussions on the future of + + align:start position:0% +of good discussions on the future of + + + align:start position:0% +of good discussions on the future of +work, on your hopes, your aspirations, a + + align:start position:0% +work, on your hopes, your aspirations, a + + + align:start position:0% +work, on your hopes, your aspirations, a +lot of discussion about the future of + + align:start position:0% +lot of discussion about the future of + + + align:start position:0% +lot of discussion about the future of +technology and how it's going to affect + + align:start position:0% +technology and how it's going to affect + + + align:start position:0% +technology and how it's going to affect +work and some of the worries that many + + align:start position:0% +work and some of the worries that many + + + align:start position:0% +work and some of the worries that many +of you have about this. So, we'll + + align:start position:0% +of you have about this. So, we'll + + + align:start position:0% +of you have about this. So, we'll +continue these discussions. We'll go + + align:start position:0% +continue these discussions. We'll go + + + align:start position:0% +continue these discussions. We'll go +into more depth on technology and work + + align:start position:0% +into more depth on technology and work + + + align:start position:0% +into more depth on technology and work +uh down uh the way in about the fourth + + align:start position:0% +uh down uh the way in about the fourth + + + align:start position:0% +uh down uh the way in about the fourth +week of class. But to give you a + + align:start position:0% +week of class. But to give you a + + + align:start position:0% +week of class. But to give you a +preview, I posted uh a new note on the + + align:start position:0% +preview, I posted uh a new note on the + + + align:start position:0% +preview, I posted uh a new note on the +discussion board about a big new MIT + + align:start position:0% +discussion board about a big new MIT + + + align:start position:0% +discussion board about a big new MIT +project on the future of the technology + + align:start position:0% +project on the future of the technology + + + align:start position:0% +project on the future of the technology +in textiles of all industries. We are + + align:start position:0% +in textiles of all industries. We are + + + align:start position:0% +in textiles of all industries. We are +about to start a big project to see if + + align:start position:0% +about to start a big project to see if + + + align:start position:0% +about to start a big project to see if +we can put some of the ideas of this + + align:start position:0% +we can put some of the ideas of this + + + align:start position:0% +we can put some of the ideas of this +course to work in practice where we + + align:start position:0% +course to work in practice where we + + + align:start position:0% +course to work in practice where we +shape the future of the textile and + + align:start position:0% +shape the future of the textile and + + + align:start position:0% +shape the future of the textile and +fabric industry with high technology + + align:start position:0% +fabric industry with high technology + + + align:start position:0% +fabric industry with high technology +jobs, hopefully good quality jobs with + + align:start position:0% +jobs, hopefully good quality jobs with + + + align:start position:0% +jobs, hopefully good quality jobs with +new training programs. So take a look at + + align:start position:0% +new training programs. So take a look at + + + align:start position:0% +new training programs. So take a look at +that post, see if you have thoughts on + + align:start position:0% +that post, see if you have thoughts on + + + align:start position:0% +that post, see if you have thoughts on +how we can shape the future of work in + + align:start position:0% +how we can shape the future of work in + + + align:start position:0% +how we can shape the future of work in +that particular sector. But this week + + align:start position:0% +that particular sector. But this week + + + align:start position:0% +that particular sector. But this week +we'll do three things. First, the videos + + align:start position:0% +we'll do three things. First, the videos + + + align:start position:0% +we'll do three things. First, the videos +that are posted for this week will give + + align:start position:0% +that are posted for this week will give + + + align:start position:0% +that are posted for this week will give +you a bit of a history of how the social + + align:start position:0% +you a bit of a history of how the social + + + align:start position:0% +you a bit of a history of how the social +contract played out and worked well in + + align:start position:0% +contract played out and worked well in + + + align:start position:0% +contract played out and worked well in +the United States and in fact in some + + align:start position:0% +the United States and in fact in some + + + align:start position:0% +the United States and in fact in some +other countries around the world in the + + align:start position:0% +other countries around the world in the + + + align:start position:0% +other countries around the world in the +past. We do this not to try to repeat + + align:start position:0% +past. We do this not to try to repeat + + + align:start position:0% +past. We do this not to try to repeat +history, but to spring forward on the + + align:start position:0% +history, but to spring forward on the + + + align:start position:0% +history, but to spring forward on the +basis of a good understanding of where + + align:start position:0% +basis of a good understanding of where + + + align:start position:0% +basis of a good understanding of where +we've come from and what we need to do + + align:start position:0% +we've come from and what we need to do + + + align:start position:0% +we've come from and what we need to do +to build a new social contract, a good + + align:start position:0% +to build a new social contract, a good + + + align:start position:0% +to build a new social contract, a good +foundation for building a new social + + align:start position:0% +foundation for building a new social + + + align:start position:0% +foundation for building a new social +contract in the future. Second, this + + align:start position:0% +contract in the future. Second, this + + + align:start position:0% +contract in the future. Second, this +week we're going to introduce some new + + align:start position:0% +week we're going to introduce some new + + + align:start position:0% +week we're going to introduce some new +uh regional discussion facilitators. Our + + align:start position:0% +uh regional discussion facilitators. Our + + + align:start position:0% +uh regional discussion facilitators. Our +M MBAs from the class I'm teaching here + + align:start position:0% +M MBAs from the class I'm teaching here + + + align:start position:0% +M MBAs from the class I'm teaching here +on campus are from all over the world, + + align:start position:0% +on campus are from all over the world, + + + align:start position:0% +on campus are from all over the world, +from China, from South Asia, from + + align:start position:0% +from China, from South Asia, from + + + align:start position:0% +from China, from South Asia, from +Africa, from Northern Europe, from + + align:start position:0% +Africa, from Northern Europe, from + + + align:start position:0% +Africa, from Northern Europe, from +Brazil. They will host discussions about + + align:start position:0% +Brazil. They will host discussions about + + + align:start position:0% +Brazil. They will host discussions about +how the issues we're talking about play + + align:start position:0% +how the issues we're talking about play + + + align:start position:0% +how the issues we're talking about play +out in your regions of the world. And we + + align:start position:0% +out in your regions of the world. And we + + + align:start position:0% +out in your regions of the world. And we +ask those of you who are from those + + align:start position:0% +ask those of you who are from those + + + align:start position:0% +ask those of you who are from those +areas to uh join that conversation. + + align:start position:0% +areas to uh join that conversation. + + + align:start position:0% +areas to uh join that conversation. +We'll even have some new experts from + + align:start position:0% +We'll even have some new experts from + + + align:start position:0% +We'll even have some new experts from +Australia, some colleagues of mine in + + align:start position:0% +Australia, some colleagues of mine in + + + align:start position:0% +Australia, some colleagues of mine in +the universities over there who study + + align:start position:0% +the universities over there who study + + + align:start position:0% +the universities over there who study +and work on these issues. So I think + + align:start position:0% +and work on these issues. So I think + + + align:start position:0% +and work on these issues. So I think +we'll have a full-bodied discussion + + align:start position:0% +we'll have a full-bodied discussion + + + align:start position:0% +we'll have a full-bodied discussion +about how the changing nature of work is + + align:start position:0% +about how the changing nature of work is + + + align:start position:0% +about how the changing nature of work is +playing out in different parts of our + + align:start position:0% +playing out in different parts of our + + + align:start position:0% +playing out in different parts of our +planet. + + align:start position:0% +planet. + + + align:start position:0% +planet. +to get uh things started on your + + align:start position:0% +to get uh things started on your + + + align:start position:0% +to get uh things started on your +personal career process. This week uh + + align:start position:0% +personal career process. This week uh + + + align:start position:0% +personal career process. This week uh +there's an assignment that will take you + + align:start position:0% +there's an assignment that will take you + + + align:start position:0% +there's an assignment that will take you +step by step through a process of + + align:start position:0% +step by step through a process of + + + align:start position:0% +step by step through a process of +identifying the kinds of issues that + + align:start position:0% +identifying the kinds of issues that + + + align:start position:0% +identifying the kinds of issues that +you're interested in. You have some + + align:start position:0% +you're interested in. You have some + + + align:start position:0% +you're interested in. You have some +aptitude toward and then the kind of + + align:start position:0% +aptitude toward and then the kind of + + + align:start position:0% +aptitude toward and then the kind of +educational levels that are available to + + align:start position:0% +educational levels that are available to + + + align:start position:0% +educational levels that are available to +get access to the jobs in fields of + + align:start position:0% +get access to the jobs in fields of + + + align:start position:0% +get access to the jobs in fields of +interest to you. So get started by going + + align:start position:0% +interest to you. So get started by going + + + align:start position:0% +interest to you. So get started by going +to the assignment uh page. Start that + + align:start position:0% +to the assignment uh page. Start that + + + align:start position:0% +to the assignment uh page. Start that +process. It'll carry through over the + + align:start position:0% +process. It'll carry through over the + + + align:start position:0% +process. It'll carry through over the +next several weeks and it's accompanied + + align:start position:0% +next several weeks and it's accompanied + + + align:start position:0% +next several weeks and it's accompanied +by several videos around the role of + + align:start position:0% +by several videos around the role of + + + align:start position:0% +by several videos around the role of +education and its changing role in + + align:start position:0% +education and its changing role in + + + align:start position:0% +education and its changing role in +lifelong learning and a special uh video + + align:start position:0% +lifelong learning and a special uh video + + + align:start position:0% +lifelong learning and a special uh video +by our colleague Lee Dyer who talks + + align:start position:0% +by our colleague Lee Dyer who talks + + + align:start position:0% +by our colleague Lee Dyer who talks +about the skills and competencies needed + + align:start position:0% +about the skills and competencies needed + + + align:start position:0% +about the skills and competencies needed +for jobs of the future. So that's what + + align:start position:0% +for jobs of the future. So that's what + + + align:start position:0% +for jobs of the future. So that's what +we'll do uh this week. But before uh we + + align:start position:0% +we'll do uh this week. But before uh we + + + align:start position:0% +we'll do uh this week. But before uh we +finish here, let's take a look at what + + align:start position:0% +finish here, let's take a look at what + + + align:start position:0% +finish here, let's take a look at what +you told us last week about your goals + + align:start position:0% +you told us last week about your goals + + + align:start position:0% +you told us last week about your goals +and your aspirations for work. + + align:start position:0% +and your aspirations for work. + + + align:start position:0% +and your aspirations for work. +Here's the results of the poll that you + + align:start position:0% +Here's the results of the poll that you + + + align:start position:0% +Here's the results of the poll that you +uh filled in about your top priority for + + align:start position:0% +uh filled in about your top priority for + + + align:start position:0% +uh filled in about your top priority for +your work and your career. Notice that + + align:start position:0% +your work and your career. Notice that + + + align:start position:0% +your work and your career. Notice that +the top item comes out to be having a + + align:start position:0% +the top item comes out to be having a + + + align:start position:0% +the top item comes out to be having a +good work life balance followed very + + align:start position:0% +good work life balance followed very + + + align:start position:0% +good work life balance followed very +closely by having a big impact on + + align:start position:0% +closely by having a big impact on + + + align:start position:0% +closely by having a big impact on +problems that are important to you and + + align:start position:0% +problems that are important to you and + + + align:start position:0% +problems that are important to you and +to society. And then in third place, but + + align:start position:0% +to society. And then in third place, but + + + align:start position:0% +to society. And then in third place, but +not too far behind, is the desire to + + align:start position:0% +not too far behind, is the desire to + + + align:start position:0% +not too far behind, is the desire to +have a good living uh from your work + + align:start position:0% +have a good living uh from your work + + + align:start position:0% +have a good living uh from your work +experiences. These are the same top + + align:start position:0% +experiences. These are the same top + + + align:start position:0% +experiences. These are the same top +three items that your colleagues last + + align:start position:0% +three items that your colleagues last + + + align:start position:0% +three items that your colleagues last +year uh indicated were their top + + align:start position:0% +year uh indicated were their top + + + align:start position:0% +year uh indicated were their top +priorities. Although this year the work + + align:start position:0% +priorities. Although this year the work + + + align:start position:0% +priorities. Although this year the work +life balance became a little bit higher + + align:start position:0% +life balance became a little bit higher + + + align:start position:0% +life balance became a little bit higher +in the ranking. So it's very clear that + + align:start position:0% +in the ranking. So it's very clear that + + + align:start position:0% +in the ranking. So it's very clear that +uh you want many things out of your jobs + + align:start position:0% +uh you want many things out of your jobs + + + align:start position:0% +uh you want many things out of your jobs +and your careers. Unlike your parents as + + align:start position:0% +and your careers. Unlike your parents as + + + align:start position:0% +and your careers. Unlike your parents as +many of you told us who focused over + + align:start position:0% +many of you told us who focused over + + + align:start position:0% +many of you told us who focused over +here on earning a good living and having + + align:start position:0% +here on earning a good living and having + + + align:start position:0% +here on earning a good living and having +a stable job, you want to be able to + + align:start position:0% +a stable job, you want to be able to + + + align:start position:0% +a stable job, you want to be able to +both have a big impact on work. You want + + align:start position:0% +both have a big impact on work. You want + + + align:start position:0% +both have a big impact on work. You want +to have a good work life balance so you + + align:start position:0% +to have a good work life balance so you + + + align:start position:0% +to have a good work life balance so you +can have a good opportunity to raise + + align:start position:0% +can have a good opportunity to raise + + + align:start position:0% +can have a good opportunity to raise +your children and have a be a good + + align:start position:0% +your children and have a be a good + + + align:start position:0% +your children and have a be a good +spouse at home or a partner at home and + + align:start position:0% +spouse at home or a partner at home and + + + align:start position:0% +spouse at home or a partner at home and +also uh earn a good living. So let's uh + + align:start position:0% +also uh earn a good living. So let's uh + + + align:start position:0% +also uh earn a good living. So let's uh +focus on how we do that. Let me give you + + align:start position:0% +focus on how we do that. Let me give you + + + align:start position:0% +focus on how we do that. Let me give you +uh a couple of examples of the rich way + + align:start position:0% +uh a couple of examples of the rich way + + + align:start position:0% +uh a couple of examples of the rich way +in which you embodied these rankings in + + align:start position:0% +in which you embodied these rankings in + + + align:start position:0% +in which you embodied these rankings in +the range of comments in the exercise + + align:start position:0% +the range of comments in the exercise + + + align:start position:0% +the range of comments in the exercise +around comparing your goals with those + + align:start position:0% +around comparing your goals with those + + + align:start position:0% +around comparing your goals with those +of your parents. This one I think + + align:start position:0% +of your parents. This one I think + + + align:start position:0% +of your parents. This one I think +captures the essence of what the poll + + align:start position:0% +captures the essence of what the poll + + + align:start position:0% +captures the essence of what the poll +told us. As one of you said, I dream of + + align:start position:0% +told us. As one of you said, I dream of + + + align:start position:0% +told us. As one of you said, I dream of +a well-balanced work family environment + + align:start position:0% +a well-balanced work family environment + + + align:start position:0% +a well-balanced work family environment +where I can develop my skills, put them + + align:start position:0% +where I can develop my skills, put them + + + align:start position:0% +where I can develop my skills, put them +to service for my community, and as well + + align:start position:0% +to service for my community, and as well + + + align:start position:0% +to service for my community, and as well +get a wage that allows me to have a + + align:start position:0% +get a wage that allows me to have a + + + align:start position:0% +get a wage that allows me to have a +decent life so that I can provide for my + + align:start position:0% +decent life so that I can provide for my + + + align:start position:0% +decent life so that I can provide for my +family and my offspring. or this one. My + + align:start position:0% +family and my offspring. or this one. My + + + align:start position:0% +family and my offspring. or this one. My +dream is to change the world by + + align:start position:0% +dream is to change the world by + + + align:start position:0% +dream is to change the world by +contributing something meaningful to it + + align:start position:0% +contributing something meaningful to it + + + align:start position:0% +contributing something meaningful to it +while maintaining a balanced lifestyle. + + align:start position:0% +while maintaining a balanced lifestyle. + + + align:start position:0% +while maintaining a balanced lifestyle. +I consider myself a global citizen. This + + align:start position:0% +I consider myself a global citizen. This + + + align:start position:0% +I consider myself a global citizen. This +is something that a number of you + + align:start position:0% +is something that a number of you + + + align:start position:0% +is something that a number of you +mentioned that you want to work and live + + align:start position:0% +mentioned that you want to work and live + + + align:start position:0% +mentioned that you want to work and live +in a culturally diverse yet an + + align:start position:0% +in a culturally diverse yet an + + + align:start position:0% +in a culturally diverse yet an +integrated workplace and lifestyle and + + align:start position:0% +integrated workplace and lifestyle and + + + align:start position:0% +integrated workplace and lifestyle and +that uh you want to push your children + + align:start position:0% +that uh you want to push your children + + + align:start position:0% +that uh you want to push your children +to be curious about their world and to + + align:start position:0% +to be curious about their world and to + + + align:start position:0% +to be curious about their world and to +push the limits of what they can do as + + align:start position:0% +push the limits of what they can do as + + + align:start position:0% +push the limits of what they can do as +they grow up. Here's another one that it + + align:start position:0% +they grow up. Here's another one that it + + + align:start position:0% +they grow up. Here's another one that it +says particularly about young + + align:start position:0% +says particularly about young + + + align:start position:0% +says particularly about young +millennials and their interest in + + align:start position:0% +millennials and their interest in + + + align:start position:0% +millennials and their interest in +working with the digital re uh + + align:start position:0% +working with the digital re uh + + + align:start position:0% +working with the digital re uh +revolution. My dream is to be part of + + align:start position:0% +revolution. My dream is to be part of + + + align:start position:0% +revolution. My dream is to be part of +the div digital revolution driven by + + align:start position:0% +the div digital revolution driven by + + + align:start position:0% +the div digital revolution driven by +mill millennials working at innovative + + align:start position:0% +mill millennials working at innovative + + + align:start position:0% +mill millennials working at innovative +companies and to make the world a better + + align:start position:0% +companies and to make the world a better + + + align:start position:0% +companies and to make the world a better +place to live and work. That theme comes + + align:start position:0% +place to live and work. That theme comes + + + align:start position:0% +place to live and work. That theme comes +through again. And then finally, I want + + align:start position:0% +through again. And then finally, I want + + + align:start position:0% +through again. And then finally, I want +to earn a living wage and not have to + + align:start position:0% +to earn a living wage and not have to + + + align:start position:0% +to earn a living wage and not have to +miss my children growing up. This is the + + align:start position:0% +miss my children growing up. This is the + + + align:start position:0% +miss my children growing up. This is the +world of work that you aspire to. This + + align:start position:0% +world of work that you aspire to. This + + + align:start position:0% +world of work that you aspire to. This +is the world of work that we have to + + align:start position:0% +is the world of work that we have to + + + align:start position:0% +is the world of work that we have to +create uh moving forward. So, let's get + + align:start position:0% +create uh moving forward. So, let's get + + + align:start position:0% +create uh moving forward. So, let's get +on with the task. This week we'll focus + + align:start position:0% +on with the task. This week we'll focus + + + align:start position:0% +on with the task. This week we'll focus +on your uh responsibilities to make sure + + align:start position:0% +on your uh responsibilities to make sure + + + align:start position:0% +on your uh responsibilities to make sure +that you are prepared to have the right + + align:start position:0% +that you are prepared to have the right + + + align:start position:0% +that you are prepared to have the right +educational levels to achieve your goals + + align:start position:0% +educational levels to achieve your goals + + + align:start position:0% +educational levels to achieve your goals +and your aspirations. And then we'll + + align:start position:0% +and your aspirations. And then we'll + + + align:start position:0% +and your aspirations. And then we'll +also look at what made the world of work + + align:start position:0% +also look at what made the world of work + + + align:start position:0% +also look at what made the world of work +more effective in some times in the past + + align:start position:0% +more effective in some times in the past + + + align:start position:0% +more effective in some times in the past +in our countries so that we can spring + + align:start position:0% +in our countries so that we can spring + + + align:start position:0% +in our countries so that we can spring +forward to think about how we build a + + align:start position:0% +forward to think about how we build a + + + align:start position:0% +forward to think about how we build a +new foundation for the future of work. \ No newline at end of file diff --git a/yL-ZljBRlWQ.txt b/yL-ZljBRlWQ.txt new file mode 100644 index 0000000000000000000000000000000000000000..bde8e7ce46f9a68058554ad3b555fc429a3ea1b2 --- /dev/null +++ b/yL-ZljBRlWQ.txt @@ -0,0 +1,4011 @@ +align:start position:0% + +Um, a a very very warm welcome, but I uh + + align:start position:0% +Um, a a very very warm welcome, but I uh + + + align:start position:0% +Um, a a very very warm welcome, but I uh +I'm going to turn it over to our um + + align:start position:0% +I'm going to turn it over to our um + + + align:start position:0% +I'm going to turn it over to our um +hosts here at MIT to do the first + + align:start position:0% +hosts here at MIT to do the first + + + align:start position:0% +hosts here at MIT to do the first +welcome. + + align:start position:0% +welcome. + + + align:start position:0% +welcome. +>> Cool. Um, can we move the slide one? + + align:start position:0% +>> Cool. Um, can we move the slide one? + + + align:start position:0% +>> Cool. Um, can we move the slide one? +>> Oh, I got it. Okay, let's see. + + align:start position:0% +>> Oh, I got it. Okay, let's see. + + + align:start position:0% +>> Oh, I got it. Okay, let's see. +Um, do you want to talk about the flying + + align:start position:0% +Um, do you want to talk about the flying + + + align:start position:0% +Um, do you want to talk about the flying +the plane? + + align:start position:0% +the plane? + + + align:start position:0% +the plane? +>> Oh my gosh, I do. Um, all right. We're + + align:start position:0% +>> Oh my gosh, I do. Um, all right. We're + + + align:start position:0% +>> Oh my gosh, I do. Um, all right. We're +going to get our This is actually the + + align:start position:0% +going to get our This is actually the + + + align:start position:0% +going to get our This is actually the +perfect slide for our little start here, + + align:start position:0% +perfect slide for our little start here, + + + align:start position:0% +perfect slide for our little start here, +which we coordinated and and rehearsed. + + align:start position:0% +which we coordinated and and rehearsed. + + + align:start position:0% +which we coordinated and and rehearsed. +Um, I I love this picture because it uh + + align:start position:0% +Um, I I love this picture because it uh + + + align:start position:0% +Um, I I love this picture because it uh +basically embodies everything that is + + align:start position:0% +basically embodies everything that is + + + align:start position:0% +basically embodies everything that is +the organization heat and and the + + align:start position:0% +the organization heat and and the + + + align:start position:0% +the organization heat and and the +process of um moving forward in + + align:start position:0% +process of um moving forward in + + + align:start position:0% +process of um moving forward in +uncertainty. So we are here today um + + align:start position:0% +uncertainty. So we are here today um + + + align:start position:0% +uncertainty. So we are here today um +with this amazing course which you'll + + align:start position:0% +with this amazing course which you'll + + + align:start position:0% +with this amazing course which you'll +about to hear more about uh building uh + + align:start position:0% +about to hear more about uh building uh + + + align:start position:0% +about to hear more about uh building uh +and fixing the airplane while flying it. + + align:start position:0% +and fixing the airplane while flying it. + + + align:start position:0% +and fixing the airplane while flying it. +Um so I I I really want to know how that + + align:start position:0% +Um so I I I really want to know how that + + + align:start position:0% +Um so I I I really want to know how that +picture came to be but + + align:start position:0% +picture came to be but + + + align:start position:0% +picture came to be but +but it it stands. So it to that end I + + align:start position:0% +but it it stands. So it to that end I + + + align:start position:0% +but it it stands. So it to that end I +want to acknowledge that you know we've + + align:start position:0% +want to acknowledge that you know we've + + + align:start position:0% +want to acknowledge that you know we've +never done this before. Um it's really + + align:start position:0% +never done this before. Um it's really + + + align:start position:0% +never done this before. Um it's really +can't it can't go wrong because of the + + align:start position:0% +can't it can't go wrong because of the + + + align:start position:0% +can't it can't go wrong because of the +people in the room + + align:start position:0% +people in the room + + + align:start position:0% +people in the room +and um we're really excited to see where + + align:start position:0% +and um we're really excited to see where + + + align:start position:0% +and um we're really excited to see where +it does go. Uh and we're also really + + align:start position:0% +it does go. Uh and we're also really + + + align:start position:0% +it does go. Uh and we're also really +excited to learn from it as always. So + + align:start position:0% +excited to learn from it as always. So + + + align:start position:0% +excited to learn from it as always. So +for example, there is a lovely + + align:start position:0% +for example, there is a lovely + + + align:start position:0% +for example, there is a lovely +whiteboard outside during your coffee + + align:start position:0% +whiteboard outside during your coffee + + + align:start position:0% +whiteboard outside during your coffee +breaks that has two sides to it. One + + align:start position:0% +breaks that has two sides to it. One + + + align:start position:0% +breaks that has two sides to it. One +side is who are the people and the ideas + + align:start position:0% +side is who are the people and the ideas + + + align:start position:0% +side is who are the people and the ideas +and the topics that we need to add to + + align:start position:0% +and the topics that we need to add to + + + align:start position:0% +and the topics that we need to add to +this conversation. + + align:start position:0% +this conversation. + + + align:start position:0% +this conversation. +Please please put your ideas there. Um + + align:start position:0% +Please please put your ideas there. Um + + + align:start position:0% +Please please put your ideas there. Um +and the other one is just general + + align:start position:0% +and the other one is just general + + + align:start position:0% +and the other one is just general +feedback. Um thoughts, ideas, learnings, + + align:start position:0% +feedback. Um thoughts, ideas, learnings, + + + align:start position:0% +feedback. Um thoughts, ideas, learnings, +changes, etc. Um please don't hesitate + + align:start position:0% +changes, etc. Um please don't hesitate + + + align:start position:0% +changes, etc. Um please don't hesitate +to give us the gift of feedback. Uh and + + align:start position:0% +to give us the gift of feedback. Uh and + + + align:start position:0% +to give us the gift of feedback. Uh and +now for the part we probably should have + + align:start position:0% +now for the part we probably should have + + + align:start position:0% +now for the part we probably should have +started with. Hi, I'm Zay McAfei. I'm + + align:start position:0% +started with. Hi, I'm Zay McAfei. I'm + + + align:start position:0% +started with. Hi, I'm Zay McAfei. I'm +the executive director of HEAT. And heat + + align:start position:0% +the executive director of HEAT. And heat + + + align:start position:0% +the executive director of HEAT. And heat +is a um is a a nonprofit that has been + + align:start position:0% +is a um is a a nonprofit that has been + + + align:start position:0% +is a um is a a nonprofit that has been +focused on trying to solve climate + + align:start position:0% +focused on trying to solve climate + + + align:start position:0% +focused on trying to solve climate +change for a lot of years uh from a + + align:start position:0% +change for a lot of years uh from a + + + align:start position:0% +change for a lot of years uh from a +community level in the beginning and um + + align:start position:0% +community level in the beginning and um + + + align:start position:0% +community level in the beginning and um +scaling. So + + align:start position:0% +scaling. So + + + align:start position:0% +scaling. So +we um will talk more about the topic of + + align:start position:0% +we um will talk more about the topic of + + + align:start position:0% +we um will talk more about the topic of +geothermal networks in a few minutes but + + align:start position:0% +geothermal networks in a few minutes but + + + align:start position:0% +geothermal networks in a few minutes but +first I want to just um express a lot of + + align:start position:0% +first I want to just um express a lot of + + + align:start position:0% +first I want to just um express a lot of +gratitude to all of you for being + + align:start position:0% +gratitude to all of you for being + + + align:start position:0% +gratitude to all of you for being +present and here and offering yourselves + + align:start position:0% +present and here and offering yourselves + + + align:start position:0% +present and here and offering yourselves +to this conversation and and journey + + align:start position:0% +to this conversation and and journey + + + align:start position:0% +to this conversation and and journey +that might might look a little hazardous + + align:start position:0% +that might might look a little hazardous + + + align:start position:0% +that might might look a little hazardous +at times. Um, and also I want to just um + + align:start position:0% +at times. Um, and also I want to just um + + + align:start position:0% +at times. Um, and also I want to just um +thank MIT the inst the amazing + + align:start position:0% +thank MIT the inst the amazing + + + align:start position:0% +thank MIT the inst the amazing +institution and both Chris and Kurt for + + align:start position:0% +institution and both Chris and Kurt for + + + align:start position:0% +institution and both Chris and Kurt for +being our hosts and I want to turn it + + align:start position:0% +being our hosts and I want to turn it + + + align:start position:0% +being our hosts and I want to turn it +over to them to introduce themselves. + + align:start position:0% +over to them to introduce themselves. + + + align:start position:0% +over to them to introduce themselves. +>> Um, thanks Anab. Uh, so yeah, I'm so + + align:start position:0% +>> Um, thanks Anab. Uh, so yeah, I'm so + + + align:start position:0% +>> Um, thanks Anab. Uh, so yeah, I'm so +excited uh to welcome heat here to MIT. + + align:start position:0% +excited uh to welcome heat here to MIT. + + + align:start position:0% +excited uh to welcome heat here to MIT. +Uh, my name is Chris Rae. I'm the + + align:start position:0% +Uh, my name is Chris Rae. I'm the + + + align:start position:0% +Uh, my name is Chris Rae. I'm the +education program director at uh MIT's + + align:start position:0% +education program director at uh MIT's + + + align:start position:0% +education program director at uh MIT's +environmental solutions initiative. Um + + align:start position:0% +environmental solutions initiative. Um + + + align:start position:0% +environmental solutions initiative. Um +the education program mission is to + + align:start position:0% +the education program mission is to + + + align:start position:0% +the education program mission is to +better understand and expand climate + + align:start position:0% +better understand and expand climate + + + align:start position:0% +better understand and expand climate +education across both uh disciplinary + + align:start position:0% +education across both uh disciplinary + + + align:start position:0% +education across both uh disciplinary +contexts and institutional contexts. And + + align:start position:0% +contexts and institutional contexts. And + + + align:start position:0% +contexts and institutional contexts. And +I'd really like to make sure that our + + align:start position:0% +I'd really like to make sure that our + + + align:start position:0% +I'd really like to make sure that our +education our projects and activities + + align:start position:0% +education our projects and activities + + + align:start position:0% +education our projects and activities +are connecting to real world uh + + align:start position:0% +are connecting to real world uh + + + align:start position:0% +are connecting to real world uh +scenarios. So it's so exciting to be + + align:start position:0% +scenarios. So it's so exciting to be + + + align:start position:0% +scenarios. So it's so exciting to be +working with heat and kind of + + align:start position:0% +working with heat and kind of + + + align:start position:0% +working with heat and kind of +reinvisioning the way that energy can + + align:start position:0% +reinvisioning the way that energy can + + + align:start position:0% +reinvisioning the way that energy can +work. Um this is a part of a few other + + align:start position:0% +work. Um this is a part of a few other + + + align:start position:0% +work. Um this is a part of a few other +collaborations. So uh we started a new + + align:start position:0% +collaborations. So uh we started a new + + + align:start position:0% +collaborations. So uh we started a new +course called environmental justice + + align:start position:0% +course called environmental justice + + + align:start position:0% +course called environmental justice +science and technology and that has a + + align:start position:0% +science and technology and that has a + + + align:start position:0% +science and technology and that has a +massive open online version and heat + + align:start position:0% +massive open online version and heat + + + align:start position:0% +massive open online version and heat +participated with a really interesting + + align:start position:0% +participated with a really interesting + + + align:start position:0% +participated with a really interesting +lecture. Um and then also we're working + + align:start position:0% +lecture. Um and then also we're working + + + align:start position:0% +lecture. Um and then also we're working +on some K through2 curriculum in this uh + + align:start position:0% +on some K through2 curriculum in this uh + + + align:start position:0% +on some K through2 curriculum in this uh +day of climate uh project through open + + align:start position:0% +day of climate uh project through open + + + align:start position:0% +day of climate uh project through open +learning. So it's just really exciting + + align:start position:0% +learning. So it's just really exciting + + + align:start position:0% +learning. So it's just really exciting +to be doing both the K through2 space + + align:start position:0% +to be doing both the K through2 space + + + align:start position:0% +to be doing both the K through2 space +and the higher education space with + + align:start position:0% +and the higher education space with + + + align:start position:0% +and the higher education space with +heat. So again just so excited for heat + + align:start position:0% +heat. So again just so excited for heat + + + align:start position:0% +heat. So again just so excited for heat +to be here. Um thank you so much. + + align:start position:0% + + + + align:start position:0% + +>> Good morning everyone. Um, my name is + + align:start position:0% +>> Good morning everyone. Um, my name is + + + align:start position:0% +>> Good morning everyone. Um, my name is +Kurt Newton. I'm director of MIT Open + + align:start position:0% +Kurt Newton. I'm director of MIT Open + + + align:start position:0% +Kurt Newton. I'm director of MIT Open +Courseware, another of the co-hosts for + + align:start position:0% +Courseware, another of the co-hosts for + + + align:start position:0% +Courseware, another of the co-hosts for +this event. Um, and we're thrilled to be + + align:start position:0% +this event. Um, and we're thrilled to be + + + align:start position:0% +this event. Um, and we're thrilled to be +participating in this, not just to host, + + align:start position:0% +participating in this, not just to host, + + + align:start position:0% +participating in this, not just to host, +but also because this is all going to + + align:start position:0% +but also because this is all going to + + + align:start position:0% +but also because this is all going to +flow out to the world. We're recording, + + align:start position:0% +flow out to the world. We're recording, + + + align:start position:0% +flow out to the world. We're recording, +as you know, we've got video set up here + + align:start position:0% +as you know, we've got video set up here + + + align:start position:0% +as you know, we've got video set up here +to um to capture and then share back + + align:start position:0% +to um to capture and then share back + + + align:start position:0% +to um to capture and then share back +with the world this important emerging + + align:start position:0% +with the world this important emerging + + + align:start position:0% +with the world this important emerging +knowledge. Um you know we've had the + + align:start position:0% +knowledge. Um you know we've had the + + + align:start position:0% +knowledge. Um you know we've had the +pleasure at open courseware with serving + + align:start position:0% +pleasure at open courseware with serving + + + align:start position:0% +pleasure at open courseware with serving +this broader mission of unlocking and + + align:start position:0% +this broader mission of unlocking and + + + align:start position:0% +this broader mission of unlocking and +empowering people around the world both + + align:start position:0% +empowering people around the world both + + + align:start position:0% +empowering people around the world both +learners and educators for over two + + align:start position:0% +learners and educators for over two + + + align:start position:0% +learners and educators for over two +decades. Um you see a screenshot of you + + align:start position:0% +decades. Um you see a screenshot of you + + + align:start position:0% +decades. Um you see a screenshot of you +know the first engagement that we had + + align:start position:0% +know the first engagement that we had + + + align:start position:0% +know the first engagement that we had +with with heat with Zanb a uh a January + + align:start position:0% +with with heat with Zanb a uh a January + + + align:start position:0% +with with heat with Zanb a uh a January +session workshop that we did uh about + + align:start position:0% +session workshop that we did uh about + + + align:start position:0% +session workshop that we did uh about +gas leaks you know part of the maybe the + + align:start position:0% +gas leaks you know part of the maybe the + + + align:start position:0% +gas leaks you know part of the maybe the +origin story for so what we're getting + + align:start position:0% +origin story for so what we're getting + + + align:start position:0% +origin story for so what we're getting +up to here um and what we do at open + + align:start position:0% +up to here um and what we do at open + + + align:start position:0% +up to here um and what we do at open +courseware is not just sharing this + + align:start position:0% +courseware is not just sharing this + + + align:start position:0% +courseware is not just sharing this +knowledge again but to do so in ways + + align:start position:0% +knowledge again but to do so in ways + + + align:start position:0% +knowledge again but to do so in ways +that um encourage practices of sharing + + align:start position:0% +that um encourage practices of sharing + + + align:start position:0% +that um encourage practices of sharing +and the feedback that gets set up + + align:start position:0% +and the feedback that gets set up + + + align:start position:0% +and the feedback that gets set up +through this through this sort of + + align:start position:0% +through this through this sort of + + + align:start position:0% +through this through this sort of +broader open knowledge ecosystem. So + + align:start position:0% +broader open knowledge ecosystem. So + + + align:start position:0% +broader open knowledge ecosystem. So +heat for instance, you know, putting all + + align:start position:0% +heat for instance, you know, putting all + + + align:start position:0% +heat for instance, you know, putting all +of these resources in an open library + + align:start position:0% +of these resources in an open library + + + align:start position:0% +of these resources in an open library +and gathering together to, you know, in + + align:start position:0% +and gathering together to, you know, in + + + align:start position:0% +and gathering together to, you know, in +a really nimble sort of generative way + + align:start position:0% +a really nimble sort of generative way + + + align:start position:0% +a really nimble sort of generative way +create this knowledge new. I I'm + + align:start position:0% +create this knowledge new. I I'm + + + align:start position:0% +create this knowledge new. I I'm +recalling here at MIT in January 2020, + + align:start position:0% +recalling here at MIT in January 2020, + + + align:start position:0% +recalling here at MIT in January 2020, +just before all kinds of stuff got shut + + align:start position:0% +just before all kinds of stuff got shut + + + align:start position:0% +just before all kinds of stuff got shut +down, we we hosted here some design + + align:start position:0% +down, we we hosted here some design + + + align:start position:0% +down, we we hosted here some design +cherettes to start this process. and + + align:start position:0% +cherettes to start this process. and + + + align:start position:0% +cherettes to start this process. and +just what a what a thrill it is to us to + + align:start position:0% +just what a what a thrill it is to us to + + + align:start position:0% +just what a what a thrill it is to us to +be kind of part of this journey + + align:start position:0% +be kind of part of this journey + + + align:start position:0% +be kind of part of this journey +together. And just to let you know if + + align:start position:0% +together. And just to let you know if + + + align:start position:0% +together. And just to let you know if +you're not familiar with open + + align:start position:0% +you're not familiar with open + + + align:start position:0% +you're not familiar with open +courseware, you know, the the reach of + + align:start position:0% +courseware, you know, the the reach of + + + align:start position:0% +courseware, you know, the the reach of +this content is considerable around the + + align:start position:0% +this content is considerable around the + + + align:start position:0% +this content is considerable around the +world. 70% of our of our visitors come + + align:start position:0% +world. 70% of our of our visitors come + + + align:start position:0% +world. 70% of our of our visitors come +from outside North America. So that the + + align:start position:0% +from outside North America. So that the + + + align:start position:0% +from outside North America. So that the +interest around the world that's + + align:start position:0% +interest around the world that's + + + align:start position:0% +interest around the world that's +developing in these technologies, we + + align:start position:0% +developing in these technologies, we + + + align:start position:0% +developing in these technologies, we +want to plug into that. Our website gets + + align:start position:0% +want to plug into that. Our website gets + + + align:start position:0% +want to plug into that. Our website gets +millions of visits every year. Um and + + align:start position:0% +millions of visits every year. Um and + + + align:start position:0% +millions of visits every year. Um and +our YouTube channel where the videos you + + align:start position:0% +our YouTube channel where the videos you + + + align:start position:0% +our YouTube channel where the videos you +know also live is also a really + + align:start position:0% +know also live is also a really + + + align:start position:0% +know also live is also a really +important point of engagement. Um with + + align:start position:0% +important point of engagement. Um with + + + align:start position:0% +important point of engagement. Um with +over five and a half million subscribers + + align:start position:0% +over five and a half million subscribers + + + align:start position:0% +over five and a half million subscribers +on our YouTube channel it's the it's the + + align:start position:0% +on our YouTube channel it's the it's the + + + align:start position:0% +on our YouTube channel it's the it's the +largest subscriber base of any sort of + + align:start position:0% +largest subscriber base of any sort of + + + align:start position:0% +largest subscriber base of any sort of +educational institution out in the + + align:start position:0% +educational institution out in the + + + align:start position:0% +educational institution out in the +world. So rest assured that that what we + + align:start position:0% +world. So rest assured that that what we + + + align:start position:0% +world. So rest assured that that what we +come up with today you know flowing out + + align:start position:0% +come up with today you know flowing out + + + align:start position:0% +come up with today you know flowing out +to the world is going to reach a lot of + + align:start position:0% +to the world is going to reach a lot of + + + align:start position:0% +to the world is going to reach a lot of +people and it's really going to I think + + align:start position:0% +people and it's really going to I think + + + align:start position:0% +people and it's really going to I think +further the the work that we're all + + align:start position:0% +further the the work that we're all + + + align:start position:0% +further the the work that we're all +trying to get up to. So welcome. + + align:start position:0% +trying to get up to. So welcome. + + + align:start position:0% +trying to get up to. So welcome. +But don't hesitate to talk after that. + + align:start position:0% + + + + align:start position:0% + +>> Thank you. My name is Isabel Varela, + + align:start position:0% +>> Thank you. My name is Isabel Varela, + + + align:start position:0% +>> Thank you. My name is Isabel Varela, +science director at HEAT. And I wanted + + align:start position:0% +science director at HEAT. And I wanted + + + align:start position:0% +science director at HEAT. And I wanted +to briefly share this is the heat team + + align:start position:0% +to briefly share this is the heat team + + + align:start position:0% +to briefly share this is the heat team +that is here to help you. If you have + + align:start position:0% +that is here to help you. If you have + + + align:start position:0% +that is here to help you. If you have +any questions, uh don't hesitate to + + align:start position:0% +any questions, uh don't hesitate to + + + align:start position:0% +any questions, uh don't hesitate to +reach out to us. + + align:start position:0% +reach out to us. + + + align:start position:0% +reach out to us. +We've put together um an incredible + + align:start position:0% +We've put together um an incredible + + + align:start position:0% +We've put together um an incredible +program. HEAT takes the aim to look at + + align:start position:0% +program. HEAT takes the aim to look at + + + align:start position:0% +program. HEAT takes the aim to look at +uh for solving a problem bring identify + + align:start position:0% +uh for solving a problem bring identify + + + align:start position:0% +uh for solving a problem bring identify +all the stakeholders that need to be + + align:start position:0% +all the stakeholders that need to be + + + align:start position:0% +all the stakeholders that need to be +involved to make that change happen and + + align:start position:0% +involved to make that change happen and + + + align:start position:0% +involved to make that change happen and +this two-day course reflects that. As + + align:start position:0% +this two-day course reflects that. As + + + align:start position:0% +this two-day course reflects that. As +you see we have eight sessions for each + + align:start position:0% +you see we have eight sessions for each + + + align:start position:0% +you see we have eight sessions for each +day and they vary from what is the + + align:start position:0% +day and they vary from what is the + + + align:start position:0% +day and they vary from what is the +challenge that we need to solve? What + + align:start position:0% +challenge that we need to solve? What + + + align:start position:0% +challenge that we need to solve? What +are the policies that need to be + + align:start position:0% +are the policies that need to be + + + align:start position:0% +are the policies that need to be +implemented to do that? Um what are the + + align:start position:0% +implemented to do that? Um what are the + + + align:start position:0% +implemented to do that? Um what are the +learnings that we can get from the + + align:start position:0% +learnings that we can get from the + + + align:start position:0% +learnings that we can get from the +geothermal networks that are implemented + + align:start position:0% +geothermal networks that are implemented + + + align:start position:0% +geothermal networks that are implemented +today? what are the design principles + + align:start position:0% +today? what are the design principles + + + align:start position:0% +today? what are the design principles +that should be applied um and learn from + + align:start position:0% +that should be applied um and learn from + + + align:start position:0% +that should be applied um and learn from +case studies. + + align:start position:0% +case studies. + + + align:start position:0% +case studies. +We are excited that you're here and we + + align:start position:0% +We are excited that you're here and we + + + align:start position:0% +We are excited that you're here and we +hope you get uh most out of this course + + align:start position:0% +hope you get uh most out of this course + + + align:start position:0% +hope you get uh most out of this course +and participate your participation makes + + align:start position:0% +and participate your participation makes + + + align:start position:0% +and participate your participation makes +the course more lively + + align:start position:0% +the course more lively + + + align:start position:0% +the course more lively +and + + align:start position:0% + + + + align:start position:0% + +we have an incredible lineup of 28 + + align:start position:0% +we have an incredible lineup of 28 + + + align:start position:0% +we have an incredible lineup of 28 +speakers that are here. Some of them + + align:start position:0% +speakers that are here. Some of them + + + align:start position:0% +speakers that are here. Some of them +have come from uh around the country to + + align:start position:0% +have come from uh around the country to + + + align:start position:0% +have come from uh around the country to +be here in these two days. And we have + + align:start position:0% +be here in these two days. And we have + + + align:start position:0% +be here in these two days. And we have +organizations represented from + + align:start position:0% +organizations represented from + + + align:start position:0% +organizations represented from +universities, gas utilities, regulators, + + align:start position:0% +universities, gas utilities, regulators, + + + align:start position:0% +universities, gas utilities, regulators, +design firms, and community- based + + align:start position:0% +design firms, and community- based + + + align:start position:0% +design firms, and community- based +organizations. So, thank you for all the + + align:start position:0% +organizations. So, thank you for all the + + + align:start position:0% +organizations. So, thank you for all the +speakers uh that are here and making + + align:start position:0% +speakers uh that are here and making + + + align:start position:0% +speakers uh that are here and making +this uh course happen. + + align:start position:0% + + + + align:start position:0% + +Um + + align:start position:0% +Um + + + align:start position:0% +Um +>> just a quick note about the nature of + + align:start position:0% +>> just a quick note about the nature of + + + align:start position:0% +>> just a quick note about the nature of +the recordings that we're going to be + + align:start position:0% +the recordings that we're going to be + + + align:start position:0% +the recordings that we're going to be +doing. So what we'll be sharing with the + + align:start position:0% +doing. So what we'll be sharing with the + + + align:start position:0% +doing. So what we'll be sharing with the +world will be the the talks + + align:start position:0% +world will be the the talks + + + align:start position:0% +world will be the the talks +um and just the videos of the talks. + + align:start position:0% +um and just the videos of the talks. + + + align:start position:0% +um and just the videos of the talks. +There's a really important sort of Q&A + + align:start position:0% +There's a really important sort of Q&A + + + align:start position:0% +There's a really important sort of Q&A +interaction segment that will happen for + + align:start position:0% +interaction segment that will happen for + + + align:start position:0% +interaction segment that will happen for +each each of the sessions and we will + + align:start position:0% +each each of the sessions and we will + + + align:start position:0% +each each of the sessions and we will +not be sharing those straight out with + + align:start position:0% +not be sharing those straight out with + + + align:start position:0% +not be sharing those straight out with +the world. We want to have a you know a + + align:start position:0% +the world. We want to have a you know a + + + align:start position:0% +the world. We want to have a you know a +frank um completely un you know + + align:start position:0% +frank um completely un you know + + + align:start position:0% +frank um completely un you know +unconstrained conversation here in the + + align:start position:0% +unconstrained conversation here in the + + + align:start position:0% +unconstrained conversation here in the +room. Our hope is though that we will be + + align:start position:0% +room. Our hope is though that we will be + + + align:start position:0% +room. Our hope is though that we will be +sharing some kind of notes and takeaways + + align:start position:0% +sharing some kind of notes and takeaways + + + align:start position:0% +sharing some kind of notes and takeaways +some summaries and synthesis from those + + align:start position:0% +some summaries and synthesis from those + + + align:start position:0% +some summaries and synthesis from those +conversations. But rest assured um + + align:start position:0% +conversations. But rest assured um + + + align:start position:0% +conversations. But rest assured um +unless you are a speaker up here. We're + + align:start position:0% +unless you are a speaker up here. We're + + + align:start position:0% +unless you are a speaker up here. We're +not expecting you to show up in these + + align:start position:0% +not expecting you to show up in these + + + align:start position:0% +not expecting you to show up in these +videos that we share on OCW. If you have + + align:start position:0% +videos that we share on OCW. If you have + + + align:start position:0% +videos that we share on OCW. If you have +any concerns or questions about that uh + + align:start position:0% +any concerns or questions about that uh + + + align:start position:0% +any concerns or questions about that uh +please reach out to me, be in touch, but + + align:start position:0% +please reach out to me, be in touch, but + + + align:start position:0% +please reach out to me, be in touch, but +hopefully that's all right. Okay. + + align:start position:0% +hopefully that's all right. Okay. + + + align:start position:0% +hopefully that's all right. Okay. +>> Uh yeah. And um our our format uh is + + align:start position:0% +>> Uh yeah. And um our our format uh is + + + align:start position:0% +>> Uh yeah. And um our our format uh is +that each session is going to have a few + + align:start position:0% +that each session is going to have a few + + + align:start position:0% +that each session is going to have a few +brief presentations. Every single one of + + align:start position:0% +brief presentations. Every single one of + + + align:start position:0% +brief presentations. Every single one of +the speakers could likely speak for + + align:start position:0% +the speakers could likely speak for + + + align:start position:0% +the speakers could likely speak for +hours uh on any one of the topics and um + + align:start position:0% +hours uh on any one of the topics and um + + + align:start position:0% +hours uh on any one of the topics and um +and we're so aware of that. But we also + + align:start position:0% +and we're so aware of that. But we also + + + align:start position:0% +and we're so aware of that. But we also +thought that the most valuable thing + + align:start position:0% +thought that the most valuable thing + + + align:start position:0% +thought that the most valuable thing +here in the room is the interaction + + align:start position:0% +here in the room is the interaction + + + align:start position:0% +here in the room is the interaction +between. Uh so for um many speakers + + align:start position:0% +between. Uh so for um many speakers + + + align:start position:0% +between. Uh so for um many speakers +there will be a longer recorded piece of + + align:start position:0% +there will be a longer recorded piece of + + + align:start position:0% +there will be a longer recorded piece of +content that's attached to the + + align:start position:0% +content that's attached to the + + + align:start position:0% +content that's attached to the +courseware. Um but in the room we're + + align:start position:0% +courseware. Um but in the room we're + + + align:start position:0% +courseware. Um but in the room we're +going to keep the presentations brief so + + align:start position:0% +going to keep the presentations brief so + + + align:start position:0% +going to keep the presentations brief so +that we can get to that part of + + align:start position:0% +that we can get to that part of + + + align:start position:0% +that we can get to that part of +interacting between and talking and + + align:start position:0% +interacting between and talking and + + + align:start position:0% +interacting between and talking and +interacting with all of you. Um, and uh, + + align:start position:0% +interacting with all of you. Um, and uh, + + + align:start position:0% +interacting with all of you. Um, and uh, +we've got a Slido. Um, it's a little app + + align:start position:0% +we've got a Slido. Um, it's a little app + + + align:start position:0% +we've got a Slido. Um, it's a little app +that we'll introduce in a second um, for + + align:start position:0% +that we'll introduce in a second um, for + + + align:start position:0% +that we'll introduce in a second um, for +you to engage so we can kind of get more + + align:start position:0% +you to engage so we can kind of get more + + + align:start position:0% +you to engage so we can kind of get more +voices involved more quickly um, so that + + align:start position:0% +voices involved more quickly um, so that + + + align:start position:0% +voices involved more quickly um, so that +we can get the conversation going. Um, + + align:start position:0% +we can get the conversation going. Um, + + + align:start position:0% +we can get the conversation going. Um, +and then I've said this already, I'm + + align:start position:0% +and then I've said this already, I'm + + + align:start position:0% +and then I've said this already, I'm +going to say it again. You know, this is + + align:start position:0% +going to say it again. You know, this is + + + align:start position:0% +going to say it again. You know, this is +this is our first go at this. Um, I I + + align:start position:0% +this is our first go at this. Um, I I + + + align:start position:0% +this is our first go at this. Um, I I +love that you mentioned the previous um, + + align:start position:0% +love that you mentioned the previous um, + + + align:start position:0% +love that you mentioned the previous um, +wonderful events. The first one was a + + align:start position:0% +wonderful events. The first one was a + + + align:start position:0% +wonderful events. The first one was a +hackathon to design a a a tool to + + align:start position:0% +hackathon to design a a a tool to + + + align:start position:0% +hackathon to design a a a tool to +measure gas leaks. Um and the second one + + align:start position:0% +measure gas leaks. Um and the second one + + + align:start position:0% +measure gas leaks. Um and the second one +was a sharet. And now we're now we're + + align:start position:0% +was a sharet. And now we're now we're + + + align:start position:0% +was a sharet. And now we're now we're +trying um this this content. So uh + + align:start position:0% +trying um this this content. So uh + + + align:start position:0% +trying um this this content. So uh +you you will you will be part of making + + align:start position:0% +you you will you will be part of making + + + align:start position:0% +you you will you will be part of making +it um wonderful today. So please don't + + align:start position:0% +it um wonderful today. So please don't + + + align:start position:0% +it um wonderful today. So please don't +hesitate to participate. All right. + + align:start position:0% +hesitate to participate. All right. + + + align:start position:0% +hesitate to participate. All right. +One last comment for housekeeping. We + + align:start position:0% +One last comment for housekeeping. We + + + align:start position:0% +One last comment for housekeeping. We +have uh breakfast in the morning + + align:start position:0% +have uh breakfast in the morning + + + align:start position:0% +have uh breakfast in the morning +outside. We'll have coffee breaks. We'll + + align:start position:0% +outside. We'll have coffee breaks. We'll + + + align:start position:0% +outside. We'll have coffee breaks. We'll +have lunch outside. Uh food is allowed + + align:start position:0% +have lunch outside. Uh food is allowed + + + align:start position:0% +have lunch outside. Uh food is allowed +to come in here if you want to. + + align:start position:0% +to come in here if you want to. + + + align:start position:0% +to come in here if you want to. +Restrooms are here immediately to the + + align:start position:0% +Restrooms are here immediately to the + + + align:start position:0% +Restrooms are here immediately to the +right and there's another one in the + + align:start position:0% +right and there's another one in the + + + align:start position:0% +right and there's another one in the +hallway uh to the left. + + align:start position:0% +hallway uh to the left. + + + align:start position:0% +hallway uh to the left. +>> Thank you. And Isabelle planned this + + align:start position:0% +>> Thank you. And Isabelle planned this + + + align:start position:0% +>> Thank you. And Isabelle planned this +incredibly. So + + align:start position:0% +incredibly. So + + + align:start position:0% +incredibly. So +>> with the tea. With the tea. + + align:start position:0% +>> with the tea. With the tea. + + + align:start position:0% +>> with the tea. With the tea. +>> Yeah. Yeah. Yeah. With with the tea. + + align:start position:0% +>> Yeah. Yeah. Yeah. With with the tea. + + + align:start position:0% +>> Yeah. Yeah. Yeah. With with the tea. +All right. So one of the things that we + + align:start position:0% +All right. So one of the things that we + + + align:start position:0% +All right. So one of the things that we +always do and and I know Kurt is always + + align:start position:0% +always do and and I know Kurt is always + + + align:start position:0% +always do and and I know Kurt is always +in on this. It's open. So, uh, your + + align:start position:0% +in on this. It's open. So, uh, your + + + align:start position:0% +in on this. It's open. So, uh, your +backgrounds here in the room are all + + align:start position:0% +backgrounds here in the room are all + + + align:start position:0% +backgrounds here in the room are all +over the spectrum. We think that's + + align:start position:0% +over the spectrum. We think that's + + + align:start position:0% +over the spectrum. We think that's +beautiful and exciting. And one of the + + align:start position:0% +beautiful and exciting. And one of the + + + align:start position:0% +beautiful and exciting. And one of the +things we're going to try to do is make + + align:start position:0% +things we're going to try to do is make + + + align:start position:0% +things we're going to try to do is make +sure that we move between um, + + align:start position:0% +sure that we move between um, + + + align:start position:0% +sure that we move between um, +introductory and advanced. And we're + + align:start position:0% +introductory and advanced. And we're + + + align:start position:0% +introductory and advanced. And we're +we're it may be a fire hose, but that's + + align:start position:0% +we're it may be a fire hose, but that's + + + align:start position:0% +we're it may be a fire hose, but that's +why we're providing coffee. Um, so I get + + align:start position:0% +why we're providing coffee. Um, so I get + + + align:start position:0% +why we're providing coffee. Um, so I get +to start us off with two quick ideas for + + align:start position:0% +to start us off with two quick ideas for + + + align:start position:0% +to start us off with two quick ideas for +the entire two days and then we have the + + align:start position:0% +the entire two days and then we have the + + + align:start position:0% +the entire two days and then we have the +most amazing panel to get going at a + + align:start position:0% +most amazing panel to get going at a + + + align:start position:0% +most amazing panel to get going at a +very like high scale level of you know + + align:start position:0% +very like high scale level of you know + + + align:start position:0% +very like high scale level of you know +the whole the whole world. Um, so + + align:start position:0% +the whole the whole world. Um, so + + + align:start position:0% +the whole the whole world. Um, so +um + + align:start position:0% +um + + + align:start position:0% +um +our our new our new uh tagline at the + + align:start position:0% +our our new our new uh tagline at the + + + align:start position:0% +our our new our new uh tagline at the +moment at HEAT is think thermal + + align:start position:0% +moment at HEAT is think thermal + + + align:start position:0% +moment at HEAT is think thermal +together. + + align:start position:0% +together. + + + align:start position:0% +together. +Um it kind of embodies a lot of the + + align:start position:0% +Um it kind of embodies a lot of the + + + align:start position:0% +Um it kind of embodies a lot of the +pieces that we're we've been learning + + align:start position:0% +pieces that we're we've been learning + + + align:start position:0% +pieces that we're we've been learning +over the past few years as we move + + align:start position:0% +over the past few years as we move + + + align:start position:0% +over the past few years as we move +forward with um networking ground source + + align:start position:0% +forward with um networking ground source + + + align:start position:0% +forward with um networking ground source +heat pumps or geothermal heat pumps. And + + align:start position:0% +heat pumps or geothermal heat pumps. And + + + align:start position:0% +heat pumps or geothermal heat pumps. And +um that idea of getting uh a problem + + align:start position:0% +um that idea of getting uh a problem + + + align:start position:0% +um that idea of getting uh a problem +solved by working together that's that's + + align:start position:0% +solved by working together that's that's + + + align:start position:0% +solved by working together that's that's +always been um there. But the piece + + align:start position:0% +always been um there. But the piece + + + align:start position:0% +always been um there. But the piece +where we realized as we as we spoke + + align:start position:0% +where we realized as we as we spoke + + + align:start position:0% +where we realized as we as we spoke +about geothermal that thermal energy + + align:start position:0% +about geothermal that thermal energy + + + align:start position:0% +about geothermal that thermal energy +itself wasn't always on the table in the + + align:start position:0% +itself wasn't always on the table in the + + + align:start position:0% +itself wasn't always on the table in the +climate solution space that people + + align:start position:0% +climate solution space that people + + + align:start position:0% +climate solution space that people +weren't thinking, they weren't + + align:start position:0% +weren't thinking, they weren't + + + align:start position:0% +weren't thinking, they weren't +measuring, they weren't talking about + + align:start position:0% +measuring, they weren't talking about + + + align:start position:0% +measuring, they weren't talking about +thermal energy. So, I'm going to just + + align:start position:0% +thermal energy. So, I'm going to just + + + align:start position:0% +thermal energy. So, I'm going to just +briefly start by getting us to take a + + align:start position:0% +briefly start by getting us to take a + + + align:start position:0% +briefly start by getting us to take a +moment to put on our thermal energy + + align:start position:0% +moment to put on our thermal energy + + + align:start position:0% +moment to put on our thermal energy +glasses. Um and then I'm going to do a + + align:start position:0% +glasses. Um and then I'm going to do a + + + align:start position:0% +glasses. Um and then I'm going to do a +little bit of housekeeping on language + + align:start position:0% +little bit of housekeeping on language + + + align:start position:0% +little bit of housekeeping on language +so that uh you know terminology and then + + align:start position:0% +so that uh you know terminology and then + + + align:start position:0% +so that uh you know terminology and then +we'll move to our first panel. Um so + + align:start position:0% +we'll move to our first panel. Um so + + + align:start position:0% +we'll move to our first panel. Um so +think thermal. Let's start with that + + align:start position:0% +think thermal. Let's start with that + + + align:start position:0% +think thermal. Let's start with that +part. Uh this is an image. If you use a + + align:start position:0% +part. Uh this is an image. If you use a + + + align:start position:0% +part. Uh this is an image. If you use a +thermal camera which actually we've + + align:start position:0% +thermal camera which actually we've + + + align:start position:0% +thermal camera which actually we've +recently purchased for the sheer fun of + + align:start position:0% +recently purchased for the sheer fun of + + + align:start position:0% +recently purchased for the sheer fun of +it. Um if you use a thermal camera you + + align:start position:0% +it. Um if you use a thermal camera you + + + align:start position:0% +it. Um if you use a thermal camera you +see things differently. um our eyes + + align:start position:0% +see things differently. um our eyes + + + align:start position:0% +see things differently. um our eyes +don't do that which may be why we don't + + align:start position:0% +don't do that which may be why we don't + + + align:start position:0% +don't do that which may be why we don't +we ignore it so often. Um but there is a + + align:start position:0% +we ignore it so often. Um but there is a + + + align:start position:0% +we ignore it so often. Um but there is a +huge amount of thermal energy in our + + align:start position:0% +huge amount of thermal energy in our + + + align:start position:0% +huge amount of thermal energy in our +earth and really if you stop and think + + align:start position:0% +earth and really if you stop and think + + + align:start position:0% +earth and really if you stop and think +about climate change what is climate + + align:start position:0% +about climate change what is climate + + + align:start position:0% +about climate change what is climate +change except a thermal energy + + align:start position:0% +change except a thermal energy + + + align:start position:0% +change except a thermal energy +regulation problem. + + align:start position:0% +regulation problem. + + + align:start position:0% +regulation problem. +And so if that's what it is and we talk + + align:start position:0% +And so if that's what it is and we talk + + + align:start position:0% +And so if that's what it is and we talk +about the rising temperature in air, + + align:start position:0% +about the rising temperature in air, + + + align:start position:0% +about the rising temperature in air, +well the kind of stunning thing is that + + align:start position:0% +well the kind of stunning thing is that + + + align:start position:0% +well the kind of stunning thing is that +uh there are a bunch of papers + + align:start position:0% +uh there are a bunch of papers + + + align:start position:0% +uh there are a bunch of papers +calculating how much thermal energy the + + align:start position:0% +calculating how much thermal energy the + + + align:start position:0% +calculating how much thermal energy the +earth has absorbed since say 1960 + + align:start position:0% +earth has absorbed since say 1960 + + + align:start position:0% +earth has absorbed since say 1960 +um and it's 630 + + align:start position:0% +um and it's 630 + + + align:start position:0% +um and it's 630 +times + + align:start position:0% +times + + + align:start position:0% +times +approximately all of the energy humanity + + align:start position:0% +approximately all of the energy humanity + + + align:start position:0% +approximately all of the energy humanity +uses every year. + + align:start position:0% +uses every year. + + + align:start position:0% +uses every year. +So I I was delighted to learn a new + + align:start position:0% +So I I was delighted to learn a new + + + align:start position:0% +So I I was delighted to learn a new +metric of energy, the zeta jewel. Um + + align:start position:0% +metric of energy, the zeta jewel. Um + + + align:start position:0% +metric of energy, the zeta jewel. Um +apparently humanity uses half a zeta + + align:start position:0% +apparently humanity uses half a zeta + + + align:start position:0% +apparently humanity uses half a zeta +jewel a year. All the energy we use. And + + align:start position:0% +jewel a year. All the energy we use. And + + + align:start position:0% +jewel a year. All the energy we use. And +every year our oceans alone are + + align:start position:0% +every year our oceans alone are + + + align:start position:0% +every year our oceans alone are +absorbing five zeta jewels. + + align:start position:0% +absorbing five zeta jewels. + + + align:start position:0% +absorbing five zeta jewels. +So that's a kind of stunning + + align:start position:0% +So that's a kind of stunning + + + align:start position:0% +So that's a kind of stunning +gut-wrenching challenge. + + align:start position:0% +gut-wrenching challenge. + + + align:start position:0% +gut-wrenching challenge. +But if you start to think about thermal + + align:start position:0% +But if you start to think about thermal + + + align:start position:0% +But if you start to think about thermal +energy, if start to look at it, if you + + align:start position:0% +energy, if start to look at it, if you + + + align:start position:0% +energy, if start to look at it, if you +start to measure it, it's also an + + align:start position:0% +start to measure it, it's also an + + + align:start position:0% +start to measure it, it's also an +extraordinary opportunity. It's a + + align:start position:0% +extraordinary opportunity. It's a + + + align:start position:0% +extraordinary opportunity. It's a +massive amount of energy all around us + + align:start position:0% +massive amount of energy all around us + + + align:start position:0% +massive amount of energy all around us +that we have been ignoring. + + align:start position:0% +that we have been ignoring. + + + align:start position:0% +that we have been ignoring. +And we have the technology to tap it, + + align:start position:0% +And we have the technology to tap it, + + + align:start position:0% +And we have the technology to tap it, +which is what we're here to talk about + + align:start position:0% +which is what we're here to talk about + + + align:start position:0% +which is what we're here to talk about +today. + + align:start position:0% +today. + + + align:start position:0% +today. +Um, a recent report from the IEA had a + + align:start position:0% +Um, a recent report from the IEA had a + + + align:start position:0% +Um, a recent report from the IEA had a +rather stunning statement um that kind + + align:start position:0% +rather stunning statement um that kind + + + align:start position:0% +rather stunning statement um that kind +of defines part of our our two days that + + align:start position:0% +of defines part of our our two days that + + + align:start position:0% +of defines part of our our two days that +the technical potential of geothermal + + align:start position:0% +the technical potential of geothermal + + + align:start position:0% +the technical potential of geothermal +would be more than enough to meet all + + align:start position:0% +would be more than enough to meet all + + + align:start position:0% +would be more than enough to meet all +heat demand. That's all heat demand. And + + align:start position:0% +heat demand. That's all heat demand. And + + + align:start position:0% +heat demand. That's all heat demand. And +they're not even talking about cooling + + align:start position:0% +they're not even talking about cooling + + + align:start position:0% +they're not even talking about cooling +in Africa, China, Europe, Southeast + + align:start position:0% +in Africa, China, Europe, Southeast + + + align:start position:0% +in Africa, China, Europe, Southeast +Asia, and the United States. So, I read + + align:start position:0% +Asia, and the United States. So, I read + + + align:start position:0% +Asia, and the United States. So, I read +that and I thought, well, what about + + align:start position:0% +that and I thought, well, what about + + + align:start position:0% +that and I thought, well, what about +those other places? Um + + align:start position:0% + + + + align:start position:0% + +but I also want to just add into the + + align:start position:0% +but I also want to just add into the + + + align:start position:0% +but I also want to just add into the +conversation not just that geothermal + + align:start position:0% +conversation not just that geothermal + + + align:start position:0% +conversation not just that geothermal +energy that's in the world all around us + + align:start position:0% +energy that's in the world all around us + + + align:start position:0% +energy that's in the world all around us +um but also + + align:start position:0% +um but also + + + align:start position:0% +um but also +uh the energy we waste all that energy + + align:start position:0% +uh the energy we waste all that energy + + + align:start position:0% +uh the energy we waste all that energy +we do use combust burn etc um the + + align:start position:0% +we do use combust burn etc um the + + + align:start position:0% +we do use combust burn etc um the +majority of it is wasted + + align:start position:0% +majority of it is wasted + + + align:start position:0% +majority of it is wasted +uh and a large large portion of that is + + align:start position:0% +uh and a large large portion of that is + + + align:start position:0% +uh and a large large portion of that is +thermal energy. So that is where we can + + align:start position:0% +thermal energy. So that is where we can + + + align:start position:0% +thermal energy. So that is where we can +think about yet another untapped + + align:start position:0% +think about yet another untapped + + + align:start position:0% +think about yet another untapped +resource all around us. All right. So + + align:start position:0% +resource all around us. All right. So + + + align:start position:0% +resource all around us. All right. So +taking the optimistic part of like wow + + align:start position:0% +taking the optimistic part of like wow + + + align:start position:0% +taking the optimistic part of like wow +there's thermal energy all around us. + + align:start position:0% +there's thermal energy all around us. + + + align:start position:0% +there's thermal energy all around us. +This is really exciting. Um what we're + + align:start position:0% +This is really exciting. Um what we're + + + align:start position:0% +This is really exciting. Um what we're +here to do today for two days is talk + + align:start position:0% +here to do today for two days is talk + + + align:start position:0% +here to do today for two days is talk +about um the technology we uh believe is + + align:start position:0% +about um the technology we uh believe is + + + align:start position:0% +about um the technology we uh believe is +there and ready for us to tap it and + + align:start position:0% +there and ready for us to tap it and + + + align:start position:0% +there and ready for us to tap it and +turn it into a solution. Um talking + + align:start position:0% +turn it into a solution. Um talking + + + align:start position:0% +turn it into a solution. Um talking +about that technology sometimes has some + + align:start position:0% +about that technology sometimes has some + + + align:start position:0% +about that technology sometimes has some +challenges. + + align:start position:0% +challenges. + + + align:start position:0% +challenges. +Um + + align:start position:0% +Um + + + align:start position:0% +Um +we we try to bring everyone together. + + align:start position:0% +we we try to bring everyone together. + + + align:start position:0% +we we try to bring everyone together. +Lots of different groups have lots of + + align:start position:0% +Lots of different groups have lots of + + + align:start position:0% +Lots of different groups have lots of +different language. Um this is kind of + + align:start position:0% +different language. Um this is kind of + + + align:start position:0% +different language. Um this is kind of +the heat approach that we've been + + align:start position:0% +the heat approach that we've been + + + align:start position:0% +the heat approach that we've been +talking about uh earlier with many other + + align:start position:0% +talking about uh earlier with many other + + + align:start position:0% +talking about uh earlier with many other +events. Um you're now part of it being + + align:start position:0% +events. Um you're now part of it being + + + align:start position:0% +events. Um you're now part of it being +in the room. Uh so coming together + + align:start position:0% +in the room. Uh so coming together + + + align:start position:0% +in the room. Uh so coming together +around what we mean when we say things + + align:start position:0% +around what we mean when we say things + + + align:start position:0% +around what we mean when we say things +is one way to start get us all on the + + align:start position:0% +is one way to start get us all on the + + + align:start position:0% +is one way to start get us all on the +same page. Um, and + + align:start position:0% + + + + align:start position:0% + +the first thing we have is a little + + align:start position:0% +the first thing we have is a little + + + align:start position:0% +the first thing we have is a little +quick intro visual, which many of you + + align:start position:0% +quick intro visual, which many of you + + + align:start position:0% +quick intro visual, which many of you +may have already seen. I apologize if + + align:start position:0% +may have already seen. I apologize if + + + align:start position:0% +may have already seen. I apologize if +you have. Um, explaining the technology + + align:start position:0% +you have. Um, explaining the technology + + + align:start position:0% +you have. Um, explaining the technology +of networking geothermal heat pumps in a + + align:start position:0% +of networking geothermal heat pumps in a + + + align:start position:0% +of networking geothermal heat pumps in a +very basic level. Tomorrow, you're going + + align:start position:0% +very basic level. Tomorrow, you're going + + + align:start position:0% +very basic level. Tomorrow, you're going +to get a very advanced level. For now, + + align:start position:0% +to get a very advanced level. For now, + + + align:start position:0% +to get a very advanced level. For now, +this is right beneath our feet. The + + align:start position:0% +this is right beneath our feet. The + + + align:start position:0% +this is right beneath our feet. The +Earth is soaking up energy from the sun. + + align:start position:0% +Earth is soaking up energy from the sun. + + + align:start position:0% +Earth is soaking up energy from the sun. +And it's been doing this for a long + + align:start position:0% +And it's been doing this for a long + + + align:start position:0% +And it's been doing this for a long +time. Near the surface, the ground warms + + align:start position:0% +time. Near the surface, the ground warms + + + align:start position:0% +time. Near the surface, the ground warms +and cools with the seasons, but lower + + align:start position:0% +and cools with the seasons, but lower + + + align:start position:0% +and cools with the seasons, but lower +down, it stays at a constant + + align:start position:0% +down, it stays at a constant + + + align:start position:0% +down, it stays at a constant +temperature. In Massachusetts, that's + + align:start position:0% +temperature. In Massachusetts, that's + + + align:start position:0% +temperature. In Massachusetts, that's +55° F year round. This store temperature + + align:start position:0% +55° F year round. This store temperature + + + align:start position:0% +55° F year round. This store temperature +is a source of renewable energy. It can + + align:start position:0% +is a source of renewable energy. It can + + + align:start position:0% +is a source of renewable energy. It can +be access to heat or cool a single + + align:start position:0% +be access to heat or cool a single + + + align:start position:0% +be access to heat or cool a single +building without using fossil fuels. But + + align:start position:0% +building without using fossil fuels. But + + + align:start position:0% +building without using fossil fuels. But +did you know we can also connect entire + + align:start position:0% +did you know we can also connect entire + + + align:start position:0% +did you know we can also connect entire +communities to that renewable source in + + align:start position:0% +communities to that renewable source in + + + align:start position:0% +communities to that renewable source in +the ground? How does it work? It starts + + align:start position:0% +the ground? How does it work? It starts + + + align:start position:0% +the ground? How does it work? It starts +with underground pipes in the streets, + + align:start position:0% +with underground pipes in the streets, + + + align:start position:0% +with underground pipes in the streets, +sort of like gas pipes, but filled only + + align:start position:0% +sort of like gas pipes, but filled only + + + align:start position:0% +sort of like gas pipes, but filled only +with water. The water absorbs the ground + + align:start position:0% +with water. The water absorbs the ground + + + align:start position:0% +with water. The water absorbs the ground +temperature of the earth and delivers it + + align:start position:0% +temperature of the earth and delivers it + + + align:start position:0% +temperature of the earth and delivers it +to buildings. Pipes connect buildings + + align:start position:0% +to buildings. Pipes connect buildings + + + align:start position:0% +to buildings. Pipes connect buildings +with different heating needs. So, energy + + align:start position:0% +with different heating needs. So, energy + + + align:start position:0% +with different heating needs. So, energy +is never wasted. Instead, it's exchanged + + align:start position:0% +is never wasted. Instead, it's exchanged + + + align:start position:0% +is never wasted. Instead, it's exchanged +between buildings or stored in the + + align:start position:0% +between buildings or stored in the + + + align:start position:0% +between buildings or stored in the +ground until it's needed. Inside, a heat + + align:start position:0% +ground until it's needed. Inside, a heat + + + align:start position:0% +ground until it's needed. Inside, a heat +pump moves heat in or out according to + + align:start position:0% +pump moves heat in or out according to + + + align:start position:0% +pump moves heat in or out according to +the temperature you want. This system of + + align:start position:0% +the temperature you want. This system of + + + align:start position:0% +the temperature you want. This system of +pipes can connect like Lego blocks. + + align:start position:0% +pipes can connect like Lego blocks. + + + align:start position:0% +pipes can connect like Lego blocks. +gradually moving us all from gas to geo, + + align:start position:0% +gradually moving us all from gas to geo, + + + align:start position:0% +gradually moving us all from gas to geo, +giving us cleaner air, efficient heating + + align:start position:0% +giving us cleaner air, efficient heating + + + align:start position:0% +giving us cleaner air, efficient heating +and cooling, and a healthier planet. The + + align:start position:0% +and cooling, and a healthier planet. The + + + align:start position:0% +and cooling, and a healthier planet. The +idea for this worked geothermal system + + align:start position:0% +idea for this worked geothermal system + + + align:start position:0% +idea for this worked geothermal system +run at a utility scale originated at + + align:start position:0% +run at a utility scale originated at + + + align:start position:0% +run at a utility scale originated at +HEAT, a climate solutions nonprofit. + + align:start position:0% +HEAT, a climate solutions nonprofit. + + + align:start position:0% +HEAT, a climate solutions nonprofit. +Uh, all right, I'm going to really + + align:start position:0% +Uh, all right, I'm going to really + + + align:start position:0% +Uh, all right, I'm going to really +quickly go through language and then get + + align:start position:0% +quickly go through language and then get + + + align:start position:0% +quickly go through language and then get +out of here for so we can start this + + align:start position:0% +out of here for so we can start this + + + align:start position:0% +out of here for so we can start this +amazing panel. Um the word geothermal uh + + align:start position:0% +amazing panel. Um the word geothermal uh + + + align:start position:0% +amazing panel. Um the word geothermal uh +if any of you are thinking about uh you + + align:start position:0% +if any of you are thinking about uh you + + + align:start position:0% +if any of you are thinking about uh you +know Iceland and hot lava that's that's + + align:start position:0% +know Iceland and hot lava that's that's + + + align:start position:0% +know Iceland and hot lava that's that's +the stuff on the left. Um this is our + + align:start position:0% +the stuff on the left. Um this is our + + + align:start position:0% +the stuff on the left. Um this is our +one way to try to clarify that + + align:start position:0% +one way to try to clarify that + + + align:start position:0% +one way to try to clarify that +geothermal is like the last name of a + + align:start position:0% +geothermal is like the last name of a + + + align:start position:0% +geothermal is like the last name of a +family of technologies and energies + + align:start position:0% +family of technologies and energies + + + align:start position:0% +family of technologies and energies +both. Um and that uh the one we are + + align:start position:0% +both. Um and that uh the one we are + + + align:start position:0% +both. Um and that uh the one we are +talking about today is on the right. It + + align:start position:0% +talking about today is on the right. It + + + align:start position:0% +talking about today is on the right. It +isworked + + align:start position:0% +isworked + + + align:start position:0% +isworked +geothermal heat pumps can provide + + align:start position:0% +geothermal heat pumps can provide + + + align:start position:0% +geothermal heat pumps can provide +heating and cooling is what is typically + + align:start position:0% +heating and cooling is what is typically + + + align:start position:0% +heating and cooling is what is typically +called shallow. You'll hear purple hear + + align:start position:0% +called shallow. You'll hear purple hear + + + align:start position:0% +called shallow. You'll hear purple hear +people use the word shallow. Um but for + + align:start position:0% +people use the word shallow. Um but for + + + align:start position:0% +people use the word shallow. Um but for +the usual person uh 1,000 or 1200 feet + + align:start position:0% +the usual person uh 1,000 or 1200 feet + + + align:start position:0% +the usual person uh 1,000 or 1200 feet +isn't doesn't sound shallow but I I + + align:start position:0% +isn't doesn't sound shallow but I I + + + align:start position:0% +isn't doesn't sound shallow but I I +promise that's shallow. Um and then uh + + align:start position:0% +promise that's shallow. Um and then uh + + + align:start position:0% +promise that's shallow. Um and then uh +it is ambient temperature. In other + + align:start position:0% +it is ambient temperature. In other + + + align:start position:0% +it is ambient temperature. In other +words kind of the average temperature of + + align:start position:0% +words kind of the average temperature of + + + align:start position:0% +words kind of the average temperature of +the air and the ground. not super hot in + + align:start position:0% +the air and the ground. not super hot in + + + align:start position:0% +the air and the ground. not super hot in +any way. Um, and uh, one of the things + + align:start position:0% +any way. Um, and uh, one of the things + + + align:start position:0% +any way. Um, and uh, one of the things +that's really critical about this type + + align:start position:0% +that's really critical about this type + + + align:start position:0% +that's really critical about this type +of geothermal energy is that it is + + align:start position:0% +of geothermal energy is that it is + + + align:start position:0% +of geothermal energy is that it is +everywhere. + + align:start position:0% +everywhere. + + + align:start position:0% +everywhere. +Um, you'll hear people talking about the + + align:start position:0% +Um, you'll hear people talking about the + + + align:start position:0% +Um, you'll hear people talking about the +word district and certainly this is a + + align:start position:0% +word district and certainly this is a + + + align:start position:0% +word district and certainly this is a +form of district energy and the + + align:start position:0% +form of district energy and the + + + align:start position:0% +form of district energy and the +traditional naming system goes by + + align:start position:0% +traditional naming system goes by + + + align:start position:0% +traditional naming system goes by +generation. first generation, second + + align:start position:0% +generation. first generation, second + + + align:start position:0% +generation. first generation, second +generation and the type we are + + align:start position:0% +generation and the type we are + + + align:start position:0% +generation and the type we are +discussing today primarily is fifth + + align:start position:0% +discussing today primarily is fifth + + + align:start position:0% +discussing today primarily is fifth +generation. Um and + + align:start position:0% +generation. Um and + + + align:start position:0% +generation. Um and +the next more advanced level of this is + + align:start position:0% +the next more advanced level of this is + + + align:start position:0% +the next more advanced level of this is +okay. So why are we calling it a network + + align:start position:0% +okay. So why are we calling it a network + + + align:start position:0% +okay. So why are we calling it a network +then? And uh our proposal which is not + + align:start position:0% +then? And uh our proposal which is not + + + align:start position:0% +then? And uh our proposal which is not +universal um but there is kind of an + + align:start position:0% +universal um but there is kind of an + + + align:start position:0% +universal um but there is kind of an +emerging nomenclature um is that within + + align:start position:0% +emerging nomenclature um is that within + + + align:start position:0% +emerging nomenclature um is that within +fifth generation um if it has a single + + align:start position:0% +fifth generation um if it has a single + + + align:start position:0% +fifth generation um if it has a single +pipe decentralized and renewable and + + align:start position:0% +pipe decentralized and renewable and + + + align:start position:0% +pipe decentralized and renewable and +combustion free then it is a thermal + + align:start position:0% +combustion free then it is a thermal + + + align:start position:0% +combustion free then it is a thermal +energy network and if that thermal + + align:start position:0% +energy network and if that thermal + + + align:start position:0% +energy network and if that thermal +energy network is tapping geothermal + + align:start position:0% +energy network is tapping geothermal + + + align:start position:0% +energy network is tapping geothermal +energy which changes some of the + + align:start position:0% +energy which changes some of the + + + align:start position:0% +energy which changes some of the +outcomes then you could also call it a + + align:start position:0% +outcomes then you could also call it a + + + align:start position:0% +outcomes then you could also call it a +geothermal energy work. That's what + + align:start position:0% +geothermal energy work. That's what + + + align:start position:0% +geothermal energy work. That's what +we're going to use, but you'll hear + + align:start position:0% +we're going to use, but you'll hear + + + align:start position:0% +we're going to use, but you'll hear +speakers use a lot of different + + align:start position:0% +speakers use a lot of different + + + align:start position:0% +speakers use a lot of different +terminology. I just wanted to give you a + + align:start position:0% +terminology. I just wanted to give you a + + + align:start position:0% +terminology. I just wanted to give you a +a quick lay of the land. Um, and our + + align:start position:0% +a quick lay of the land. Um, and our + + + align:start position:0% +a quick lay of the land. Um, and our +last task before we begin is if you + + align:start position:0% +last task before we begin is if you + + + align:start position:0% +last task before we begin is if you +could please take out your phone. We + + align:start position:0% +could please take out your phone. We + + + align:start position:0% +could please take out your phone. We +have um this QR code you can scan and it + + align:start position:0% +have um this QR code you can scan and it + + + align:start position:0% +have um this QR code you can scan and it +should work pretty easily to get you on + + align:start position:0% +should work pretty easily to get you on + + + align:start position:0% +should work pretty easily to get you on +to Slido. And now you have um your first + + align:start position:0% +to Slido. And now you have um your first + + + align:start position:0% +to Slido. And now you have um your first +quiz. + + align:start position:0% +quiz. + + + align:start position:0% +quiz. +We did say class, right? + + align:start position:0% +We did say class, right? + + + align:start position:0% +We did say class, right? +No, don't don't worry. There's actually + + align:start position:0% +No, don't don't worry. There's actually + + + align:start position:0% +No, don't don't worry. There's actually +no test. Uh but um + + align:start position:0% +no test. Uh but um + + + align:start position:0% +no test. Uh but um +let's see how you do. + + align:start position:0% +let's see how you do. + + + align:start position:0% +let's see how you do. +Yeah, I made it too easy. + + align:start position:0% + + + + align:start position:0% + +So, if you have any trouble getting on, + + align:start position:0% +So, if you have any trouble getting on, + + + align:start position:0% +So, if you have any trouble getting on, +um, Erica back there is happy to help. + + align:start position:0% +um, Erica back there is happy to help. + + + align:start position:0% +um, Erica back there is happy to help. +>> You can also, you can also open your web + + align:start position:0% +>> You can also, you can also open your web + + + align:start position:0% +>> You can also, you can also open your web +browser and just go to slid.com and type + + align:start position:0% +browser and just go to slid.com and type + + + align:start position:0% +browser and just go to slid.com and type +in. + + align:start position:0% + + + + align:start position:0% + +>> All right. + + align:start position:0% + + + + align:start position:0% + +I like watching them go out and back. + + align:start position:0% +I like watching them go out and back. + + + align:start position:0% +I like watching them go out and back. +That's how I think. + + align:start position:0% + + + + align:start position:0% + +All right. Are we good? + + align:start position:0% +All right. Are we good? + + + align:start position:0% +All right. Are we good? +everyone on slidoh now for the rest of + + align:start position:0% +everyone on slidoh now for the rest of + + + align:start position:0% +everyone on slidoh now for the rest of +the day. Okay. Uh so yes um the the + + align:start position:0% +the day. Okay. Uh so yes um the the + + + align:start position:0% +the day. Okay. Uh so yes um the the +group um the group wisdom is prevailing. + + align:start position:0% +group um the group wisdom is prevailing. + + + align:start position:0% +group um the group wisdom is prevailing. +Uh the type of geothermal energy we're + + align:start position:0% +Uh the type of geothermal energy we're + + + align:start position:0% +Uh the type of geothermal energy we're +discussing today is ambient shallow and + + align:start position:0% +discussing today is ambient shallow and + + + align:start position:0% +discussing today is ambient shallow and +everywhere. Um which is a lovely + + align:start position:0% +everywhere. Um which is a lovely + + + align:start position:0% +everywhere. Um which is a lovely +feature. + + align:start position:0% +feature. + + + align:start position:0% +feature. +Um all right. So, we're going to take a + + align:start position:0% +Um all right. So, we're going to take a + + + align:start position:0% +Um all right. So, we're going to take a +a second and um begin our first uh + + align:start position:0% +a second and um begin our first uh + + + align:start position:0% +a second and um begin our first uh +conversation. \ No newline at end of file diff --git a/zHa-n2M7Bj8.txt b/zHa-n2M7Bj8.txt new file mode 100644 index 0000000000000000000000000000000000000000..4d0babe280daf698593b2e79e45fd369ae4c9782 --- /dev/null +++ b/zHa-n2M7Bj8.txt @@ -0,0 +1,7011 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license + + align:start position:0% +a Creative Commons license + + + align:start position:0% +a Creative Commons license +your support will help MIT + + align:start position:0% +your support will help MIT + + + align:start position:0% +your support will help MIT +OpenCourseWare continue to offer high + + align:start position:0% +OpenCourseWare continue to offer high + + + align:start position:0% +OpenCourseWare continue to offer high +quality educational resources for free + + align:start position:0% +quality educational resources for free + + + align:start position:0% +quality educational resources for free +to make a donation or view additional + + align:start position:0% +to make a donation or view additional + + + align:start position:0% +to make a donation or view additional +materials from hundreds of MIT courses + + align:start position:0% +materials from hundreds of MIT courses + + + align:start position:0% +materials from hundreds of MIT courses +visit MIT opencourseware at ocw.mit.edu + + align:start position:0% +visit MIT opencourseware at ocw.mit.edu + + + align:start position:0% +visit MIT opencourseware at ocw.mit.edu +so we saw in Laura's talk this + + align:start position:0% +so we saw in Laura's talk this + + + align:start position:0% +so we saw in Laura's talk this +introduction to both this idea of the + + align:start position:0% +introduction to both this idea of the + + + align:start position:0% +introduction to both this idea of the +child as scientists right all the + + align:start position:0% +child as scientists right all the + + + align:start position:0% +child as scientists right all the +different ways that children's learning + + align:start position:0% +different ways that children's learning + + + align:start position:0% +different ways that children's learning +seems to follow the many different + + align:start position:0% +seems to follow the many different + + + align:start position:0% +seems to follow the many different +practices that scientists use to learn + + align:start position:0% +practices that scientists use to learn + + + align:start position:0% +practices that scientists use to learn +about the world not just the data + + align:start position:0% +about the world not just the data + + + align:start position:0% +about the world not just the data +analysis of in a sense if you know if + + align:start position:0% +analysis of in a sense if you know if + + + align:start position:0% +analysis of in a sense if you know if +well you know as much as you know + + align:start position:0% +well you know as much as you know + + + align:start position:0% +well you know as much as you know +various kinds of statistics on a grand + + align:start position:0% +various kinds of statistics on a grand + + + align:start position:0% +various kinds of statistics on a grand +scale whether it's heavy and learning or + + align:start position:0% +scale whether it's heavy and learning or + + + align:start position:0% +scale whether it's heavy and learning or +backprop are important for learning we + + align:start position:0% +backprop are important for learning we + + + align:start position:0% +backprop are important for learning we +know that that's not all that children + + align:start position:0% +know that that's not all that children + + + align:start position:0% +know that that's not all that children +do just like analyzing patterns and data + + align:start position:0% +do just like analyzing patterns and data + + + align:start position:0% +do just like analyzing patterns and data +is not all that scientists do and then + + align:start position:0% +is not all that scientists do and then + + + align:start position:0% +is not all that scientists do and then +Laura added this other cool dimension + + align:start position:0% +Laura added this other cool dimension + + + align:start position:0% +Laura added this other cool dimension +thinking about the costs and rewards of + + align:start position:0% +thinking about the costs and rewards of + + + align:start position:0% +thinking about the costs and rewards of +information right when is it worth it or + + align:start position:0% +information right when is it worth it or + + + align:start position:0% +information right when is it worth it or +not and you could say maybe she was + + align:start position:0% +not and you could say maybe she was + + + align:start position:0% +not and you could say maybe she was +suggesting that we should develop the + + align:start position:0% +suggesting that we should develop the + + + align:start position:0% +suggesting that we should develop the +metaphor expand it a little bit from + + align:start position:0% +metaphor expand it a little bit from + + + align:start position:0% +metaphor expand it a little bit from +child a scientist maybe like the child + + align:start position:0% +child a scientist maybe like the child + + + align:start position:0% +child a scientist maybe like the child +as labs + + align:start position:0% +as labs + + + align:start position:0% +as labs +sorry lab p.i or maybe even NSF center + + align:start position:0% +sorry lab p.i or maybe even NSF center + + + align:start position:0% +sorry lab p.i or maybe even NSF center +director because as everyone knows but + + align:start position:0% +director because as everyone knows but + + + align:start position:0% +director because as everyone knows but +Tommy certainly can tell you whether + + align:start position:0% +Tommy certainly can tell you whether + + + align:start position:0% +Tommy certainly can tell you whether +you're a lab p.i who's just gotten + + align:start position:0% +you're a lab p.i who's just gotten + + + align:start position:0% +you're a lab p.i who's just gotten +tenure or at the director of an NSF + + align:start position:0% +tenure or at the director of an NSF + + + align:start position:0% +tenure or at the director of an NSF +Center you have to make you know + + align:start position:0% +Center you have to make you know + + + align:start position:0% +Center you have to make you know +hard-nosed pragmatic decisions about + + align:start position:0% +hard-nosed pragmatic decisions about + + + align:start position:0% +hard-nosed pragmatic decisions about +what is achievable given the costs and + + align:start position:0% +what is achievable given the costs and + + + align:start position:0% +what is achievable given the costs and +which research questions are really + + align:start position:0% +which research questions are really + + + align:start position:0% +which research questions are really +worth going after and devoting your time + + align:start position:0% +worth going after and devoting your time + + + align:start position:0% +worth going after and devoting your time +and other resources to and that's that's + + align:start position:0% +and other resources to and that's that's + + + align:start position:0% +and other resources to and that's that's +a very important part of science and + + align:start position:0% +a very important part of science and + + + align:start position:0% +a very important part of science and +it's an important part of intuitive + + align:start position:0% +it's an important part of intuitive + + + align:start position:0% +it's an important part of intuitive +knowledge I want to add another + + align:start position:0% +knowledge I want to add another + + + align:start position:0% +knowledge I want to add another +practical dimension two things a way of + + align:start position:0% +practical dimension two things a way of + + + align:start position:0% +practical dimension two things a way of +bringing out fleshing out this idea of + + align:start position:0% +bringing out fleshing out this idea of + + + align:start position:0% +bringing out fleshing out this idea of +the child as scientist you can think + + align:start position:0% +the child as scientist you can think + + + align:start position:0% +the child as scientist you can think +about all these are these are metaphors + + align:start position:0% +about all these are these are metaphors + + + align:start position:0% +about all these are these are metaphors +but they're things that we can formalize + + align:start position:0% +but they're things that we can formalize + + + align:start position:0% +but they're things that we can formalize +and if our goal is to make computational + + align:start position:0% +and if our goal is to make computational + + + align:start position:0% +and if our goal is to make computational +models of and ultimately to get some + + align:start position:0% +models of and ultimately to get some + + + align:start position:0% +models of and ultimately to get some +kind of theoretical handle on then these + + align:start position:0% +kind of theoretical handle on then these + + + align:start position:0% +kind of theoretical handle on then these +are helping us right by by adding in the + + align:start position:0% +are helping us right by by adding in the + + + align:start position:0% +are helping us right by by adding in the +cost and benefits you bring in utility + + align:start position:0% +cost and benefits you bring in utility + + + align:start position:0% +cost and benefits you bring in utility +calculus and there's not just naive + + align:start position:0% +calculus and there's not just naive + + + align:start position:0% +calculus and there's not just naive +utility calculus there's a formal + + align:start position:0% +utility calculus there's a formal + + + align:start position:0% +utility calculus there's a formal +mathematical utility calculus of these + + align:start position:0% +mathematical utility calculus of these + + + align:start position:0% +mathematical utility calculus of these +kinds of decisions Julianne ha Redinger + + align:start position:0% +kinds of decisions Julianne ha Redinger + + + align:start position:0% +kinds of decisions Julianne ha Redinger +whoo Laura mentioned a lot of the was + + align:start position:0% +whoo Laura mentioned a lot of the was + + + align:start position:0% +whoo Laura mentioned a lot of the was +driving a lot of the work towards the + + align:start position:0% +driving a lot of the work towards the + + + align:start position:0% +driving a lot of the work towards the +end of the talk has done some really + + align:start position:0% +end of the talk has done some really + + + align:start position:0% +end of the talk has done some really +interesting actual + + align:start position:0% +interesting actual + + + align:start position:0% +interesting actual +automatical computational models of + + align:start position:0% +automatical computational models of + + + align:start position:0% +automatical computational models of +these issues as has CEO and the other + + align:start position:0% +these issues as has CEO and the other + + + align:start position:0% +these issues as has CEO and the other +students you talked about um so the the + + align:start position:0% +students you talked about um so the the + + + align:start position:0% +students you talked about um so the the +direction I want to push here is what + + align:start position:0% +direction I want to push here is what + + + align:start position:0% +direction I want to push here is what +you might call the child as hacker right + + align:start position:0% +you might call the child as hacker right + + + align:start position:0% +you might call the child as hacker right +this is trying to make the connection + + align:start position:0% +this is trying to make the connection + + + align:start position:0% +this is trying to make the connection +back to this idea of formalizing + + align:start position:0% +back to this idea of formalizing + + + align:start position:0% +back to this idea of formalizing +common-sense knowledge and intuitive + + align:start position:0% +common-sense knowledge and intuitive + + + align:start position:0% +common-sense knowledge and intuitive +theories as probabilistic programs or + + align:start position:0% +theories as probabilistic programs or + + + align:start position:0% +theories as probabilistic programs or +just more generally the idea of a + + align:start position:0% +just more generally the idea of a + + + align:start position:0% +just more generally the idea of a +program a structured out you know an + + align:start position:0% +program a structured out you know an + + + align:start position:0% +program a structured out you know an +algorithm and a date or some combination + + align:start position:0% +algorithm and a date or some combination + + + align:start position:0% +algorithm and a date or some combination +of algorithms data structures networks + + align:start position:0% +of algorithms data structures networks + + + align:start position:0% +of algorithms data structures networks +of functions that can describe + + align:start position:0% +of functions that can describe + + + align:start position:0% +of functions that can describe +interesting causal processes in the + + align:start position:0% +interesting causal processes in the + + + align:start position:0% +interesting causal processes in the +world like for example your intuitive + + align:start position:0% +world like for example your intuitive + + + align:start position:0% +world like for example your intuitive +physics or your intuitive psychology + + align:start position:0% +physics or your intuitive psychology + + + align:start position:0% +physics or your intuitive psychology +that's an idea that we talked a lot + + align:start position:0% +that's an idea that we talked a lot + + + align:start position:0% +that's an idea that we talked a lot +about last week or whenever it was + + align:start position:0% +about last week or whenever it was + + + align:start position:0% +about last week or whenever it was +earlier in the week or last week and + + align:start position:0% +earlier in the week or last week and + + + align:start position:0% +earlier in the week or last week and +this this idea that if if your knowledge + + align:start position:0% +this this idea that if if your knowledge + + + align:start position:0% +this this idea that if if your knowledge +is something like a program or a set of + + align:start position:0% +is something like a program or a set of + + + align:start position:0% +is something like a program or a set of +programs that you can say for example + + align:start position:0% +programs that you can say for example + + + align:start position:0% +programs that you can say for example +run forward to simulate physics like we + + align:start position:0% +run forward to simulate physics like we + + + align:start position:0% +run forward to simulate physics like we +had last time then learning has to be + + align:start position:0% +had last time then learning has to be + + + align:start position:0% +had last time then learning has to be +something like building a program or + + align:start position:0% +something like building a program or + + + align:start position:0% +something like building a program or +hacking and I think you could make this + + align:start position:0% +hacking and I think you could make this + + + align:start position:0% +hacking and I think you could make this +is again a research program that I wish + + align:start position:0% +is again a research program that I wish + + + align:start position:0% +is again a research program that I wish +I had like Laura talked at the end about + + align:start position:0% +I had like Laura talked at the end about + + + align:start position:0% +I had like Laura talked at the end about +the research for him she wished she had + + align:start position:0% +the research for him she wished she had + + + align:start position:0% +the research for him she wished she had +it's it's it's not really a wit just to + + align:start position:0% +it's it's it's not really a wit just to + + + align:start position:0% +it's it's it's not really a wit just to +wish for her she actually is working + + align:start position:0% +wish for her she actually is working + + + align:start position:0% +wish for her she actually is working +towards that research program and this + + align:start position:0% +towards that research program and this + + + align:start position:0% +towards that research program and this +isn't just an empty wish either it's + + align:start position:0% +isn't just an empty wish either it's + + + align:start position:0% +isn't just an empty wish either it's +something that we're working on which is + + align:start position:0% +something that we're working on which is + + + align:start position:0% +something that we're working on which is +to try to take um just as Laura had that + + align:start position:0% +to try to take um just as Laura had that + + + align:start position:0% +to try to take um just as Laura had that +wonderful list of all the things + + align:start position:0% +wonderful list of all the things + + + align:start position:0% +wonderful list of all the things +scientists do in their practices to + + align:start position:0% +scientists do in their practices to + + + align:start position:0% +scientists do in their practices to +learn about the world I think you could + + align:start position:0% +learn about the world I think you could + + + align:start position:0% +learn about the world I think you could +make a similar list of all the things + + align:start position:0% +make a similar list of all the things + + + align:start position:0% +make a similar list of all the things +that you do when you're programming + + align:start position:0% +that you do when you're programming + + + align:start position:0% +that you do when you're programming +right or hacking it by hacking I don't + + align:start position:0% +right or hacking it by hacking I don't + + + align:start position:0% +right or hacking it by hacking I don't +mean right like breaking into a secure + + align:start position:0% +mean right like breaking into a secure + + + align:start position:0% +mean right like breaking into a secure +system but modifying your code to make + + align:start position:0% +system but modifying your code to make + + + align:start position:0% +system but modifying your code to make +it more awesome either more and I use + + align:start position:0% +it more awesome either more and I use + + + align:start position:0% +it more awesome either more and I use +awesome very deliberately right because + + align:start position:0% +awesome very deliberately right because + + + align:start position:0% +awesome very deliberately right because +awesome is a multi-dimensional term it's + + align:start position:0% +awesome is a multi-dimensional term it's + + + align:start position:0% +awesome is a multi-dimensional term it's +just awesome but it could be it could be + + align:start position:0% +just awesome but it could be it could be + + + align:start position:0% +just awesome but it could be it could be +faster more accurate more efficient more + + align:start position:0% +faster more accurate more efficient more + + + align:start position:0% +faster more accurate more efficient more +elegant more generalizable more easily + + align:start position:0% +elegant more generalizable more easily + + + align:start position:0% +elegant more generalizable more easily +communicated to other people more easily + + align:start position:0% +communicated to other people more easily + + + align:start position:0% +communicated to other people more easily +modularly combined with other code to do + + align:start position:0% +modularly combined with other code to do + + + align:start position:0% +modularly combined with other code to do +something even more awesome right I + + align:start position:0% +something even more awesome right I + + + align:start position:0% +something even more awesome right I +think there's a deep sense in which that + + align:start position:0% +think there's a deep sense in which that + + + align:start position:0% +think there's a deep sense in which that +aesthetic behind hacking and making + + align:start position:0% +aesthetic behind hacking and making + + + align:start position:0% +aesthetic behind hacking and making +awesome code in it both an individual in + + align:start position:0% +awesome code in it both an individual in + + + align:start position:0% +awesome code in it both an individual in +a social setting that's a really + + align:start position:0% +a social setting that's a really + + + align:start position:0% +a social setting that's a really +powerful way to think about many of the + + align:start position:0% +powerful way to think about many of the + + + align:start position:0% +powerful way to think about many of the +cognitive activities behind learning and + + align:start position:0% +cognitive activities behind learning and + + + align:start position:0% +cognitive activities behind learning and +it goes together with the idea of the + + align:start position:0% +it goes together with the idea of the + + + align:start position:0% +it goes together with the idea of the +childís scientist right if the form of + + align:start position:0% +childís scientist right if the form of + + + align:start position:0% +childís scientist right if the form of +your of your code intuitive science our + + align:start position:0% +your of your code intuitive science our + + + align:start position:0% +your of your code intuitive science our +computer programs + + align:start position:0% +computer programs + + + align:start position:0% +computer programs +or something like programs so we've been + + align:start position:0% +or something like programs so we've been + + + align:start position:0% +or something like programs so we've been +working on a few projects where you've + + align:start position:0% +working on a few projects where you've + + + align:start position:0% +working on a few projects where you've +been trying to capture this idea and to + + align:start position:0% +been trying to capture this idea and to + + + align:start position:0% +been trying to capture this idea and to +say well what would it mean to describe + + align:start position:0% +say well what would it mean to describe + + + align:start position:0% +say well what would it mean to describe +computationally this idea of learning as + + align:start position:0% +computationally this idea of learning as + + + align:start position:0% +computationally this idea of learning as +either synthesizing programs or + + align:start position:0% +either synthesizing programs or + + + align:start position:0% +either synthesizing programs or +modifying programs or making the + + align:start position:0% +modifying programs or making the + + + align:start position:0% +modifying programs or making the +program's of making more awesome + + align:start position:0% +program's of making more awesome + + + align:start position:0% +program's of making more awesome +programs in your mind and I'll just show + + align:start position:0% +programs in your mind and I'll just show + + + align:start position:0% +programs in your mind and I'll just show +you a few examples of this I'll show you + + align:start position:0% +you a few examples of this I'll show you + + + align:start position:0% +you a few examples of this I'll show you +our good our successful case studies + + align:start position:0% +our good our successful case studies + + + align:start position:0% +our good our successful case studies +places where we've made this idea work + + align:start position:0% +places where we've made this idea work + + + align:start position:0% +places where we've made this idea work +but the bottom line to foreshadow it is + + align:start position:0% +but the bottom line to foreshadow it is + + + align:start position:0% +but the bottom line to foreshadow it is +that this is really really hard and to + + align:start position:0% +that this is really really hard and to + + + align:start position:0% +that this is really really hard and to +get it to work for the kinds of + + align:start position:0% +get it to work for the kinds of + + + align:start position:0% +get it to work for the kinds of +knowledge that say Laura was talking + + align:start position:0% +knowledge that say Laura was talking + + + align:start position:0% +knowledge that say Laura was talking +about or that Liz was talking about the + + align:start position:0% +about or that Liz was talking about the + + + align:start position:0% +about or that Liz was talking about the +real stuff of children's solid is still + + align:start position:0% +real stuff of children's solid is still + + + align:start position:0% +real stuff of children's solid is still +very very open and that's really we want + + align:start position:0% +very very open and that's really we want + + + align:start position:0% +very very open and that's really we want +to basically build up to engaging why + + align:start position:0% +to basically build up to engaging why + + + align:start position:0% +to basically build up to engaging why +that - why that problem is so hard from + + align:start position:0% +that - why that problem is so hard from + + + align:start position:0% +that - why that problem is so hard from +this to what Tomer and then Laura will + + align:start position:0% +this to what Tomer and then Laura will + + + align:start position:0% +this to what Tomer and then Laura will +talk about later on in the afternoon so + + align:start position:0% +talk about later on in the afternoon so + + + align:start position:0% +talk about later on in the afternoon so +here but here's a few at least early + + align:start position:0% +here but here's a few at least early + + + align:start position:0% +here but here's a few at least early +success stories that we've worked on one + + align:start position:0% +success stories that we've worked on one + + + align:start position:0% +success stories that we've worked on one +goes back to this idea that we presented + + align:start position:0% +goes back to this idea that we presented + + + align:start position:0% +goes back to this idea that we presented +it in my lectures last week and it + + align:start position:0% +it in my lectures last week and it + + + align:start position:0% +it in my lectures last week and it +connects to again something that Laura + + align:start position:0% +connects to again something that Laura + + + align:start position:0% +connects to again something that Laura +was saying here you know a very basic + + align:start position:0% +was saying here you know a very basic + + + align:start position:0% +was saying here you know a very basic +kind of learning is just the problem of + + align:start position:0% +kind of learning is just the problem of + + + align:start position:0% +kind of learning is just the problem of +learning some generalizable concepts at + + align:start position:0% +learning some generalizable concepts at + + + align:start position:0% +learning some generalizable concepts at +all from from very sparse evidence like + + align:start position:0% +all from from very sparse evidence like + + + align:start position:0% +all from from very sparse evidence like +one-shot learning you again something + + align:start position:0% +one-shot learning you again something + + + align:start position:0% +one-shot learning you again something +you heard from Tommy a number of the + + align:start position:0% +you heard from Tommy a number of the + + + align:start position:0% +you heard from Tommy a number of the +other speakers we've all been trying to + + align:start position:0% +other speakers we've all been trying to + + + align:start position:0% +other speakers we've all been trying to +wrap our heads around this how can you + + align:start position:0% +wrap our heads around this how can you + + + align:start position:0% +wrap our heads around this how can you +learn safe any concept at all from very + + align:start position:0% +learn safe any concept at all from very + + + align:start position:0% +learn safe any concept at all from very +very little data maybe just one or a few + + align:start position:0% +very little data maybe just one or a few + + + align:start position:0% +very little data maybe just one or a few +examples so you saw this kind of thing + + align:start position:0% +examples so you saw this kind of thing + + + align:start position:0% +examples so you saw this kind of thing +last time and I briefly mentioned how we + + align:start position:0% +last time and I briefly mentioned how we + + + align:start position:0% +last time and I briefly mentioned how we +had tried to capture this this problem + + align:start position:0% +had tried to capture this this problem + + + align:start position:0% +had tried to capture this this problem +as some something like this by building + + align:start position:0% +as some something like this by building + + + align:start position:0% +as some something like this by building +this tree structured hypothesis space + + align:start position:0% +this tree structured hypothesis space + + + align:start position:0% +this tree structured hypothesis space +and you could think of this as a kind of + + align:start position:0% +and you could think of this as a kind of + + + align:start position:0% +and you could think of this as a kind of +program induction if you think that + + align:start position:0% +program induction if you think that + + + align:start position:0% +program induction if you think that +there's something like an evolutionary + + align:start position:0% +there's something like an evolutionary + + + align:start position:0% +there's something like an evolutionary +program which generated these objects + + align:start position:0% +program which generated these objects + + + align:start position:0% +program which generated these objects +and you're trying to find the kind of + + align:start position:0% +and you're trying to find the kind of + + + align:start position:0% +and you're trying to find the kind of +sub procedure of it that generated just + + align:start position:0% +sub procedure of it that generated just + + + align:start position:0% +sub procedure of it that generated just +these kinds of objects but that's not + + align:start position:0% +these kinds of objects but that's not + + + align:start position:0% +these kinds of objects but that's not +that's not at all how we were able to + + align:start position:0% +that's not at all how we were able to + + + align:start position:0% +that's not at all how we were able to +model this I mean we had a much simpler + + align:start position:0% +model this I mean we had a much simpler + + + align:start position:0% +model this I mean we had a much simpler +model but let me show you briefly some + + align:start position:0% +model but let me show you briefly some + + + align:start position:0% +model but let me show you briefly some +work that we did in our group a couple + + align:start position:0% +work that we did in our group a couple + + + align:start position:0% +work that we did in our group a couple +of years ago it's really just getting + + align:start position:0% +of years ago it's really just getting + + + align:start position:0% +of years ago it's really just getting +out into publication now this is work + + align:start position:0% +out into publication now this is work + + + align:start position:0% +out into publication now this is work +that was mostly done by two people + + align:start position:0% +that was mostly done by two people + + + align:start position:0% +that was mostly done by two people +Russell akuti noff who's now a professor + + align:start position:0% +Russell akuti noff who's now a professor + + + align:start position:0% +Russell akuti noff who's now a professor +at Toronto although about to move to + + align:start position:0% +at Toronto although about to move to + + + align:start position:0% +at Toronto although about to move to +Carnegie Mellon I think and Brendan Lake + + align:start position:0% +Carnegie Mellon I think and Brendan Lake + + + align:start position:0% +Carnegie Mellon I think and Brendan Lake +he's a machine learning person also very + + align:start position:0% +he's a machine learning person also very + + + align:start position:0% +he's a machine learning person also very +well known for deep learning and then + + align:start position:0% +well known for deep learning and then + + + align:start position:0% +well known for deep learning and then +Brendan Lake this is really mostly all + + align:start position:0% +Brendan Lake this is really mostly all + + + align:start position:0% +Brendan Lake this is really mostly all +I'll talk about is Brendan Lakes + + align:start position:0% +I'll talk about is Brendan Lakes + + + align:start position:0% +I'll talk about is Brendan Lakes +work who is now a postdoc at NYU and we + + align:start position:0% +work who is now a postdoc at NYU and we + + + align:start position:0% +work who is now a postdoc at NYU and we +you know again where we think we're + + align:start position:0% +you know again where we think we're + + + align:start position:0% +you know again where we think we're +building up to is trying to learn + + align:start position:0% +building up to is trying to learn + + + align:start position:0% +building up to is trying to learn +something like a the program of an + + align:start position:0% +something like a the program of an + + + align:start position:0% +something like a the program of an +intuitive physics or intuitive + + align:start position:0% +intuitive physics or intuitive + + + align:start position:0% +intuitive physics or intuitive +psychology but here we're just talking + + align:start position:0% +psychology but here we're just talking + + + align:start position:0% +psychology but here we're just talking +about learning object concepts and we've + + align:start position:0% +about learning object concepts and we've + + + align:start position:0% +about learning object concepts and we've +been doing this work with the data set + + align:start position:0% +been doing this work with the data set + + + align:start position:0% +been doing this work with the data set +of handwritten characters the ones you + + align:start position:0% +of handwritten characters the ones you + + + align:start position:0% +of handwritten characters the ones you +see on the right here I'll just put it + + align:start position:0% +see on the right here I'll just put it + + + align:start position:0% +see on the right here I'll just put it +up in contrast or by comparison to say + + align:start position:0% +up in contrast or by comparison to say + + + align:start position:0% +up in contrast or by comparison to say +this other much more famous data set of + + align:start position:0% +this other much more famous data set of + + + align:start position:0% +this other much more famous data set of +Hendrick characters the emne Stata set + + align:start position:0% +Hendrick characters the emne Stata set + + + align:start position:0% +Hendrick characters the emne Stata set +how many people have seen the endless + + align:start position:0% +how many people have seen the endless + + + align:start position:0% +how many people have seen the endless +data set maybe in some of the previous + + align:start position:0% +data set maybe in some of the previous + + + align:start position:0% +data set maybe in some of the previous +talks how people have actually used it + + align:start position:0% +talks how people have actually used it + + + align:start position:0% +talks how people have actually used it +yeah it's a great data set to use it's + + align:start position:0% +yeah it's a great data set to use it's + + + align:start position:0% +yeah it's a great data set to use it's +driven a lot of basic machine learning + + align:start position:0% +driven a lot of basic machine learning + + + align:start position:0% +driven a lot of basic machine learning +research including deep learning Yann + + align:start position:0% +research including deep learning Yann + + + align:start position:0% +research including deep learning Yann +laocoon originally collected this data + + align:start position:0% +laocoon originally collected this data + + + align:start position:0% +laocoon originally collected this data +set and put this out there and geoff + + align:start position:0% +set and put this out there and geoff + + + align:start position:0% +set and put this out there and geoff +hinton did most of the development of + + align:start position:0% +hinton did most of the development of + + + align:start position:0% +hinton did most of the development of +the stuff that now wins object + + align:start position:0% +the stuff that now wins object + + + align:start position:0% +the stuff that now wins object +recognition challenges was done on this + + align:start position:0% +recognition challenges was done on this + + + align:start position:0% +recognition challenges was done on this +data set but not only that also a lot of + + align:start position:0% +data set but not only that also a lot of + + + align:start position:0% +data set but not only that also a lot of +bayesian stuff and probabilistic + + align:start position:0% +bayesian stuff and probabilistic + + + align:start position:0% +bayesian stuff and probabilistic +generative models now the the the thing + + align:start position:0% +generative models now the the the thing + + + align:start position:0% +generative models now the the the thing +about that data set though right is it + + align:start position:0% +about that data set though right is it + + + align:start position:0% +about that data set though right is it +has a very small number of classes just + + align:start position:0% +has a very small number of classes just + + + align:start position:0% +has a very small number of classes just +the digits 0 through 9 and a huge number + + align:start position:0% +the digits 0 through 9 and a huge number + + + align:start position:0% +the digits 0 through 9 and a huge number +of examples about you know roughly + + align:start position:0% +of examples about you know roughly + + + align:start position:0% +of examples about you know roughly +10,000 examples in each class or maybe + + align:start position:0% +10,000 examples in each class or maybe + + + align:start position:0% +10,000 examples in each class or maybe +six thousand examples something like + + align:start position:0% +six thousand examples something like + + + align:start position:0% +six thousand examples something like +that but we wanted to construct a data + + align:start position:0% +that but we wanted to construct a data + + + align:start position:0% +that but we wanted to construct a data +set which was similar in some ways in + + align:start position:0% +set which was similar in some ways in + + + align:start position:0% +set which was similar in some ways in +its complexity and scale but which which + + align:start position:0% +its complexity and scale but which which + + + align:start position:0% +its complexity and scale but which which +where we had many many more concepts and + + align:start position:0% +where we had many many more concepts and + + + align:start position:0% +where we had many many more concepts and +many perhaps many fewer examples so here + + align:start position:0% +many perhaps many fewer examples so here + + + align:start position:0% +many perhaps many fewer examples so here +we we got people to write by hand + + align:start position:0% +we we got people to write by hand + + + align:start position:0% +we we got people to write by hand +characters in 50 different alphabets and + + align:start position:0% +characters in 50 different alphabets and + + + align:start position:0% +characters in 50 different alphabets and +it's a really cool data set so that + + align:start position:0% +it's a really cool data set so that + + + align:start position:0% +it's a really cool data set so that +total data set has on 1623 concepts + + align:start position:0% +total data set has on 1623 concepts + + + align:start position:0% +total data set has on 1623 concepts +drawn which are which are you know you + + align:start position:0% +drawn which are which are you know you + + + align:start position:0% +drawn which are which are you know you +can call them handwritten characters you + + align:start position:0% +can call them handwritten characters you + + + align:start position:0% +can call them handwritten characters you +could just call them simple visual + + align:start position:0% +could just call them simple visual + + + align:start position:0% +could just call them simple visual +concepts and so as sort of a warm-up for + + align:start position:0% +concepts and so as sort of a warm-up for + + + align:start position:0% +concepts and so as sort of a warm-up for +bigger problems of say natural objects + + align:start position:0% +bigger problems of say natural objects + + + align:start position:0% +bigger problems of say natural objects +and there's a there's 20 examples per + + align:start position:0% +and there's a there's 20 examples per + + + align:start position:0% +and there's a there's 20 examples per +class so there's roughly 30,000 total + + align:start position:0% +class so there's roughly 30,000 total + + + align:start position:0% +class so there's roughly 30,000 total +data points in this data set just very + + align:start position:0% +data points in this data set just very + + + align:start position:0% +data points in this data set just very +much like a mist um you can see just + + align:start position:0% +much like a mist um you can see just + + + align:start position:0% +much like a mist um you can see just +just to illustrate here there's many + + align:start position:0% +just to illustrate here there's many + + + align:start position:0% +just to illustrate here there's many +different alphabets that have very + + align:start position:0% +different alphabets that have very + + + align:start position:0% +different alphabets that have very +different forms you can see both the + + align:start position:0% +different forms you can see both the + + + align:start position:0% +different forms you can see both the +similarities and differences within + + align:start position:0% +similarities and differences within + + + align:start position:0% +similarities and differences within +between alphabets here right some of the + + align:start position:0% +between alphabets here right some of the + + + align:start position:0% +between alphabets here right some of the +alphabet so so so so in that sense + + align:start position:0% +alphabet so so so so in that sense + + + align:start position:0% +alphabet so so so so in that sense +there's kind of a hierarchical structure + + align:start position:0% +there's kind of a hierarchical structure + + + align:start position:0% +there's kind of a hierarchical structure +right each one of these is a character + + align:start position:0% +right each one of these is a character + + + align:start position:0% +right each one of these is a character +in an alphabet but there's also the + + align:start position:0% +in an alphabet but there's also the + + + align:start position:0% +in an alphabet but there's also the +higher level concept of a sort of a Sam + + align:start position:0% +higher level concept of a sort of a Sam + + + align:start position:0% +higher level concept of a sort of a Sam +script form as + + align:start position:0% +script form as + + + align:start position:0% +script form as +thing from say Tagalog or Hebrew or + + align:start position:0% +thing from say Tagalog or Hebrew or + + + align:start position:0% +thing from say Tagalog or Hebrew or +Braille right there's some made-up + + align:start position:0% +Braille right there's some made-up + + + align:start position:0% +Braille right there's some made-up +alphabets but you know one of the neat + + align:start position:0% +alphabets but you know one of the neat + + + align:start position:0% +alphabets but you know one of the neat +things about this domain is that you can + + align:start position:0% +things about this domain is that you can + + + align:start position:0% +things about this domain is that you can +make up new concepts and you can make up + + align:start position:0% +make up new concepts and you can make up + + + align:start position:0% +make up new concepts and you can make up +new whole concepts of concepts like + + align:start position:0% +new whole concepts of concepts like + + + align:start position:0% +new whole concepts of concepts like +whole new alphabets + + align:start position:0% +whole new alphabets + + + align:start position:0% +whole new alphabets +you can do one-shot learning in it so we + + align:start position:0% +you can do one-shot learning in it so we + + + align:start position:0% +you can do one-shot learning in it so we +can let's just try this out here for a + + align:start position:0% +can let's just try this out here for a + + + align:start position:0% +can let's just try this out here for a +second you'll remember the tufa demo we + + align:start position:0% +second you'll remember the tufa demo we + + + align:start position:0% +second you'll remember the tufa demo we +can do the same kind of thing here like + + align:start position:0% +can do the same kind of thing here like + + + align:start position:0% +can do the same kind of thing here like +let's take these characters anybody know + + align:start position:0% +let's take these characters anybody know + + + align:start position:0% +let's take these characters anybody know +the alphabet that this is okay that's + + align:start position:0% +the alphabet that this is okay that's + + + align:start position:0% +the alphabet that this is okay that's +good most of you have not seen these + + align:start position:0% +good most of you have not seen these + + + align:start position:0% +good most of you have not seen these +before okay that's good that you know + + align:start position:0% +before okay that's good that you know + + + align:start position:0% +before okay that's good that you know +but let will do this exponent on the + + align:start position:0% +but let will do this exponent on the + + + align:start position:0% +but let will do this exponent on the +rest of you so here's a one example of a + + align:start position:0% +rest of you so here's a one example of a + + + align:start position:0% +rest of you so here's a one example of a +concept call it a tufa if you like and + + align:start position:0% +concept call it a tufa if you like and + + + align:start position:0% +concept call it a tufa if you like and +I'll just run my mouse over these other + + align:start position:0% +I'll just run my mouse over these other + + + align:start position:0% +I'll just run my mouse over these other +ones and you just clap when I get to the + + align:start position:0% +ones and you just clap when I get to the + + + align:start position:0% +ones and you just clap when I get to the +other example of the same class okay + + align:start position:0% + + + + align:start position:0% + +okay very good yeah people are basically + + align:start position:0% +okay very good yeah people are basically + + + align:start position:0% +okay very good yeah people are basically +perfect at this you just it doesn't take + + align:start position:0% +perfect at this you just it doesn't take + + + align:start position:0% +perfect at this you just it doesn't take +I mean again it's it's very fast and + + align:start position:0% +I mean again it's it's very fast and + + + align:start position:0% +I mean again it's it's very fast and +almost perfect and and just like again + + align:start position:0% +almost perfect and and just like again + + + align:start position:0% +almost perfect and and just like again +you you saw me talk a little about this + + align:start position:0% +you you saw me talk a little about this + + + align:start position:0% +you you saw me talk a little about this +last time just like with natural objects + + align:start position:0% +last time just like with natural objects + + + align:start position:0% +last time just like with natural objects +not only can you learn one of these + + align:start position:0% +not only can you learn one of these + + + align:start position:0% +not only can you learn one of these +concepts from one example and generalize + + align:start position:0% +concepts from one example and generalize + + + align:start position:0% +concepts from one example and generalize +it to others but you can use that + + align:start position:0% +it to others but you can use that + + + align:start position:0% +it to others but you can use that +knowledge in various other ways right so + + align:start position:0% +knowledge in various other ways right so + + + align:start position:0% +knowledge in various other ways right so +you can parse these things into parts we + + align:start position:0% +you can parse these things into parts we + + + align:start position:0% +you can parse these things into parts we +think that's part of what you're doing + + align:start position:0% +think that's part of what you're doing + + + align:start position:0% +think that's part of what you're doing +you can generate new examples so here + + align:start position:0% +you can generate new examples so here + + + align:start position:0% +you can generate new examples so here +are three different people all drawing + + align:start position:0% +are three different people all drawing + + + align:start position:0% +are three different people all drawing +the same character and in fact the whole + + align:start position:0% +the same character and in fact the whole + + + align:start position:0% +the same character and in fact the whole +data set was generated that way you can + + align:start position:0% +data set was generated that way you can + + + align:start position:0% +data set was generated that way you can +also make higher-level generalizations + + align:start position:0% +also make higher-level generalizations + + + align:start position:0% +also make higher-level generalizations +right recombining the parts into totally + + align:start position:0% +right recombining the parts into totally + + + align:start position:0% +right recombining the parts into totally +new concepts the way there's that weird + + align:start position:0% +new concepts the way there's that weird + + + align:start position:0% +new concepts the way there's that weird +kind of like eunice unicycle thing over + + align:start position:0% +kind of like eunice unicycle thing over + + + align:start position:0% +kind of like eunice unicycle thing over +there + + align:start position:0% +there + + + align:start position:0% +there +you know motorcycle here you know you + + align:start position:0% +you know motorcycle here you know you + + + align:start position:0% +you know motorcycle here you know you +can I can show you as you'll see ten + + align:start position:0% +can I can show you as you'll see ten + + + align:start position:0% +can I can show you as you'll see ten +characters in a new alphabet and you can + + align:start position:0% +characters in a new alphabet and you can + + + align:start position:0% +characters in a new alphabet and you can +make up hypothetical if perhaps + + align:start position:0% +make up hypothetical if perhaps + + + align:start position:0% +make up hypothetical if perhaps +incorrect examples in it I mean again + + align:start position:0% +incorrect examples in it I mean again + + + align:start position:0% +incorrect examples in it I mean again +I'm just going to show you a couple of + + align:start position:0% +I'm just going to show you a couple of + + + align:start position:0% +I'm just going to show you a couple of +case studies of where this idea of + + align:start position:0% +case studies of where this idea of + + + align:start position:0% +case studies of where this idea of +learning as program synthesis might work + + align:start position:0% +learning as program synthesis might work + + + align:start position:0% +learning as program synthesis might work +so the idea here is that you know kind + + align:start position:0% +so the idea here is that you know kind + + + align:start position:0% +so the idea here is that you know kind +of as you as you might see these are + + align:start position:0% +of as you as you might see these are + + + align:start position:0% +of as you as you might see these are +three characters down on the bottom and + + align:start position:0% +three characters down on the bottom and + + + align:start position:0% +three characters down on the bottom and +this is just a very schematic diagram of + + align:start position:0% +this is just a very schematic diagram of + + + align:start position:0% +this is just a very schematic diagram of +how our model tries to represent these + + align:start position:0% +how our model tries to represent these + + + align:start position:0% +how our model tries to represent these +as simple kinds of programs think about + + align:start position:0% +as simple kinds of programs think about + + + align:start position:0% +as simple kinds of programs think about +how you would draw say that character + + align:start position:0% +how you would draw say that character + + + align:start position:0% +how you would draw say that character +down at the bottom just try to draw it + + align:start position:0% +down at the bottom just try to draw it + + + align:start position:0% +down at the bottom just try to draw it +in in midair or just for every you know + + align:start position:0% +in in midair or just for every you know + + + align:start position:0% +in in midair or just for every you know +just how would you draw that one in the + + align:start position:0% +just how would you draw that one in the + + + align:start position:0% +just how would you draw that one in the +lower left there are many of you doing + + align:start position:0% +lower left there are many of you doing + + + align:start position:0% +lower left there are many of you doing +something like this is that what you're + + align:start position:0% +something like this is that what you're + + + align:start position:0% +something like this is that what you're +doing okay yeah so basically everyone + + align:start position:0% +doing okay yeah so basically everyone + + + align:start position:0% +doing okay yeah so basically everyone +does that and you can describe that as + + align:start position:0% +does that and you can describe that as + + + align:start position:0% +does that and you can describe that as +sort of having two large parts or two + + align:start position:0% +sort of having two large parts or two + + + align:start position:0% +sort of having two large parts or two +strokes where you pick up your pen + + align:start position:0% +strokes where you pick up your pen + + + align:start position:0% +strokes where you pick up your pen +between strokes and one of the strokes + + align:start position:0% +between strokes and one of the strokes + + + align:start position:0% +between strokes and one of the strokes +has two sub strokes where you stop your + + align:start position:0% +has two sub strokes where you stop your + + + align:start position:0% +has two sub strokes where you stop your +pen and there's a consistent + + align:start position:0% +pen and there's a consistent + + + align:start position:0% +pen and there's a consistent +relationship the second stroke has two + + align:start position:0% +relationship the second stroke has two + + + align:start position:0% +relationship the second stroke has two +begins somewhere on a particular general + + align:start position:0% +begins somewhere on a particular general + + + align:start position:0% +begins somewhere on a particular general +region of the first stroke and basically + + align:start position:0% +region of the first stroke and basically + + + align:start position:0% +region of the first stroke and basically +the model that's the models + + align:start position:0% +the model that's the models + + + align:start position:0% +the model that's the models +representation of concepts parts sub + + align:start position:0% +representation of concepts parts sub + + + align:start position:0% +representation of concepts parts sub +parts and simple relations which you can + + align:start position:0% +parts and simple relations which you can + + + align:start position:0% +parts and simple relations which you can +see you know might scale up arguably to + + align:start position:0% +see you know might scale up arguably to + + + align:start position:0% +see you know might scale up arguably to +more interesting kinds of natural + + align:start position:0% +more interesting kinds of natural + + + align:start position:0% +more interesting kinds of natural +objects and the basic idea is that you + + align:start position:0% +objects and the basic idea is that you + + + align:start position:0% +objects and the basic idea is that you +represent that though as a program it's + + align:start position:0% +represent that though as a program it's + + + align:start position:0% +represent that though as a program it's +a generative program it's kind of like a + + align:start position:0% +a generative program it's kind of like a + + + align:start position:0% +a generative program it's kind of like a +motor program but it's more abstract we + + align:start position:0% +motor program but it's more abstract we + + + align:start position:0% +motor program but it's more abstract we +don't think we think that when you see + + align:start position:0% +don't think we think that when you see + + + align:start position:0% +don't think we think that when you see +these characters and many other concepts + + align:start position:0% +these characters and many other concepts + + + align:start position:0% +these characters and many other concepts +you represent something about + + align:start position:0% +you represent something about + + + align:start position:0% +you represent something about +you might create it but it doesn't mean + + align:start position:0% +you might create it but it doesn't mean + + + align:start position:0% +you might create it but it doesn't mean +it's in your muscles you could use other + + align:start position:0% +it's in your muscles you could use other + + + align:start position:0% +it's in your muscles you could use other +hands you could use your toe or you + + align:start position:0% +hands you could use your toe or you + + + align:start position:0% +hands you could use your toe or you +could even just think about it in your + + align:start position:0% +could even just think about it in your + + + align:start position:0% +could even just think about it in your +imagination so the model basically tries + + align:start position:0% +imagination so the model basically tries + + + align:start position:0% +imagination so the model basically tries +to induce these simple think about them + + align:start position:0% +to induce these simple think about them + + + align:start position:0% +to induce these simple think about them +is like maybe simple hierarchical plans + + align:start position:0% +is like maybe simple hierarchical plans + + + align:start position:0% +is like maybe simple hierarchical plans +simple action programs and it does it by + + align:start position:0% +simple action programs and it does it by + + + align:start position:0% +simple action programs and it does it by +having a program generating program that + + align:start position:0% +having a program generating program that + + + align:start position:0% +having a program generating program that +can itself have parameters that can be + + align:start position:0% +can itself have parameters that can be + + + align:start position:0% +can itself have parameters that can be +learned from data so this right right + + align:start position:0% +learned from data so this right right + + + align:start position:0% +learned from data so this right right +here this is a program called generate + + align:start position:0% +here this is a program called generate + + + align:start position:0% +here this is a program called generate +type and what that does is it's a + + align:start position:0% +type and what that does is it's a + + + align:start position:0% +type and what that does is it's a +program a type means a character concept + + align:start position:0% +program a type means a character concept + + + align:start position:0% +program a type means a character concept +like each of those three things is a + + align:start position:0% +like each of those three things is a + + + align:start position:0% +like each of those three things is a +different type this is a program which + + align:start position:0% +different type this is a program which + + + align:start position:0% +different type this is a program which +generates a program that generates the + + align:start position:0% +generates a program that generates the + + + align:start position:0% +generates a program that generates the +actual character that the second level + + align:start position:0% +actual character that the second level + + + align:start position:0% +actual character that the second level +of program is called generate token + + align:start position:0% +of program is called generate token + + + align:start position:0% +of program is called generate token +that's a program which draws a + + align:start position:0% +that's a program which draws a + + + align:start position:0% +that's a program which draws a +particular instance of a character and + + align:start position:0% +particular instance of a character and + + + align:start position:0% +particular instance of a character and +you can you know just like you can draw + + align:start position:0% +you can you know just like you can draw + + + align:start position:0% +you can you know just like you can draw +many examples of any concept you can + + align:start position:0% +many examples of any concept you can + + + align:start position:0% +many examples of any concept you can +call that function many times generate + + align:start position:0% +call that function many times generate + + + align:start position:0% +call that function many times generate +token generate token generate token so + + align:start position:0% +token generate token generate token so + + + align:start position:0% +token generate token generate token so +your concept of a character is a + + align:start position:0% +your concept of a character is a + + + align:start position:0% +your concept of a character is a +generative function and in order to + + align:start position:0% +generative function and in order to + + + align:start position:0% +generative function and in order to +learn this you have basically a prior on + + align:start position:0% +learn this you have basically a prior on + + + align:start position:0% +learn this you have basically a prior on +those programs that comes from a program + + align:start position:0% +those programs that comes from a program + + + align:start position:0% +those programs that comes from a program +generating program that's the generate + + align:start position:0% +generating program that's the generate + + + align:start position:0% +generating program that's the generate +type program so there's a lot of details + + align:start position:0% +type program so there's a lot of details + + + align:start position:0% +type program so there's a lot of details +behind how this works but basically the + + align:start position:0% +behind how this works but basically the + + + align:start position:0% +behind how this works but basically the +the model does a kind of learning to + + align:start position:0% +the model does a kind of learning to + + + align:start position:0% +the model does a kind of learning to +learn from a held out unsupervised set + + align:start position:0% +learn from a held out unsupervised set + + + align:start position:0% +learn from a held out unsupervised set +and sort of learns the program of the + + align:start position:0% +and sort of learns the program of the + + + align:start position:0% +and sort of learns the program of the +parameters of this program generating + + align:start position:0% +parameters of this program generating + + + align:start position:0% +parameters of this program generating +program which kind of would characterize + + align:start position:0% +program which kind of would characterize + + + align:start position:0% +program which kind of would characterize +how we draw things in general how + + align:start position:0% +how we draw things in general how + + + align:start position:0% +how we draw things in general how +characters what they look like in + + align:start position:0% +characters what they look like in + + + align:start position:0% +characters what they look like in +general and then when you see a new + + align:start position:0% +general and then when you see a new + + + align:start position:0% +general and then when you see a new +character like this one what effectively + + align:start position:0% +character like this one what effectively + + + align:start position:0% +character like this one what effectively +what the model is doing is it's it's + + align:start position:0% +what the model is doing is it's it's + + + align:start position:0% +what the model is doing is it's it's +both kind of parsing this into its parts + + align:start position:0% +both kind of parsing this into its parts + + + align:start position:0% +both kind of parsing this into its parts +and subparts and relations but that + + align:start position:0% +and subparts and relations but that + + + align:start position:0% +and subparts and relations but that +parsing is basically the program + + align:start position:0% +parsing is basically the program + + + align:start position:0% +parsing is basically the program +synthesis it is pretty much the same + + align:start position:0% +synthesis it is pretty much the same + + + align:start position:0% +synthesis it is pretty much the same +thing you're constructing you're looking + + align:start position:0% +thing you're constructing you're looking + + + align:start position:0% +thing you're constructing you're looking +at that output of some program and + + align:start position:0% +at that output of some program and + + + align:start position:0% +at that output of some program and +saying what would be the best simple set + + align:start position:0% +saying what would be the best simple set + + + align:start position:0% +saying what would be the best simple set +of parts and subparts and relations that + + align:start position:0% +of parts and subparts and relations that + + + align:start position:0% +of parts and subparts and relations that +could draw that and then I'm gonna infer + + align:start position:0% +could draw that and then I'm gonna infer + + + align:start position:0% +could draw that and then I'm gonna infer +the most likely one and then use that as + + align:start position:0% +the most likely one and then use that as + + + align:start position:0% +the most likely one and then use that as +a generalizable template or program I + + align:start position:0% +a generalizable template or program I + + + align:start position:0% +a generalizable template or program I +can then generate other characters with + + align:start position:0% +can then generate other characters with + + + align:start position:0% +can then generate other characters with +so here it may be to just illustrate + + align:start position:0% +so here it may be to just illustrate + + + align:start position:0% +so here it may be to just illustrate +really concretely um if you were to see + + align:start position:0% +really concretely um if you were to see + + + align:start position:0% +really concretely um if you were to see +this character here well here's here's + + align:start position:0% +this character here well here's here's + + + align:start position:0% +this character here well here's here's +one instance of one class here's an into + + align:start position:0% +one instance of one class here's an into + + + align:start position:0% +one instance of one class here's an into +another class again I have no idea which + + align:start position:0% +another class again I have no idea which + + + align:start position:0% +another class again I have no idea which +alphabet this is now what about this one + + align:start position:0% +alphabet this is now what about this one + + + align:start position:0% +alphabet this is now what about this one +is it class 1 or class 2 what do you + + align:start position:0% +is it class 1 or class 2 what do you + + + align:start position:0% +is it class 1 or class 2 what do you +think what yeah anybody think it's class + + align:start position:0% +think what yeah anybody think it's class + + + align:start position:0% +think what yeah anybody think it's class +2 okay so how do we know it's class 1 + + align:start position:0% +2 okay so how do we know it's class 1 + + + align:start position:0% +2 okay so how do we know it's class 1 +well at the pixel level it doesn't look + + align:start position:0% +well at the pixel level it doesn't look + + + align:start position:0% +well at the pixel level it doesn't look +any + + align:start position:0% +any + + + align:start position:0% +any +like that right so this is again an + + align:start position:0% +like that right so this is again an + + + align:start position:0% +like that right so this is again an +example some of the issues that Tommy + + align:start position:0% +example some of the issues that Tommy + + + align:start position:0% +example some of the issues that Tommy +was talking about a really severe kind + + align:start position:0% +was talking about a really severe kind + + + align:start position:0% +was talking about a really severe kind +of invariance but it's not just + + align:start position:0% +of invariance but it's not just + + + align:start position:0% +of invariance but it's not just +translation or scale invariance although + + align:start position:0% +translation or scale invariance although + + + align:start position:0% +translation or scale invariance although +it does have some of that but it also + + align:start position:0% +it does have some of that but it also + + + align:start position:0% +it does have some of that but it also +has this kind of interesting with in + + align:start position:0% +has this kind of interesting with in + + + align:start position:0% +has this kind of interesting with in +class invariance right there's it's a + + align:start position:0% +class invariance right there's it's a + + + align:start position:0% +class invariance right there's it's a +rather different shape it's been + + align:start position:0% +rather different shape it's been + + + align:start position:0% +rather different shape it's been +distorted somewhat so a program is a + + align:start position:0% +distorted somewhat so a program is a + + + align:start position:0% +distorted somewhat so a program is a +powerful way to capture that where you + + align:start position:0% +powerful way to capture that where you + + + align:start position:0% +powerful way to capture that where you +can say well if you hear if you you + + align:start position:0% +can say well if you hear if you you + + + align:start position:0% +can say well if you hear if you you +wouldn't do something like the program + + align:start position:0% +wouldn't do something like the program + + + align:start position:0% +wouldn't do something like the program +for generating this which is like one + + align:start position:0% +for generating this which is like one + + + align:start position:0% +for generating this which is like one +stroke like that and then these other + + align:start position:0% +stroke like that and then these other + + + align:start position:0% +stroke like that and then these other +two things that's shown with the red and + + align:start position:0% +two things that's shown with the red and + + + align:start position:0% +two things that's shown with the red and +green and here's a program that you + + align:start position:0% +green and here's a program that you + + + align:start position:0% +green and here's a program that you +might induce to generate that and then + + align:start position:0% +might induce to generate that and then + + + align:start position:0% +might induce to generate that and then +the question is which of these is most + + align:start position:0% +the question is which of these is most + + + align:start position:0% +the question is which of these is most +or which of these two programs simple + + align:start position:0% +or which of these two programs simple + + + align:start position:0% +or which of these two programs simple +motor hierarchical motor programs is + + align:start position:0% +motor hierarchical motor programs is + + + align:start position:0% +motor hierarchical motor programs is +most likely to generate that character + + align:start position:0% +most likely to generate that character + + + align:start position:0% +most likely to generate that character +and it turns out that it's incredibly + + align:start position:0% +and it turns out that it's incredibly + + + align:start position:0% +and it turns out that it's incredibly +unlikely to generate any character from + + align:start position:0% +unlikely to generate any character from + + + align:start position:0% +unlikely to generate any character from +one of these programs but these are the + + align:start position:0% +one of these programs but these are the + + + align:start position:0% +one of these programs but these are the +logs scores the log probabilities so + + align:start position:0% +logs scores the log probabilities so + + + align:start position:0% +logs scores the log probabilities so +this one is like 2 to the negative 758 + + align:start position:0% +this one is like 2 to the negative 758 + + + align:start position:0% +this one is like 2 to the negative 758 +and this one is like 2 to the negative + + align:start position:0% +and this one is like 2 to the negative + + + align:start position:0% +and this one is like 2 to the negative +18 hundred and 80 I don't know if it's + + align:start position:0% +18 hundred and 80 I don't know if it's + + + align:start position:0% +18 hundred and 80 I don't know if it's +base years maybe 2 or 8 but whatever so + + align:start position:0% +base years maybe 2 or 8 but whatever so + + + align:start position:0% +base years maybe 2 or 8 but whatever so +each of these is very small but this one + + align:start position:0% +each of these is very small but this one + + + align:start position:0% +each of these is very small but this one +is like a thousand orders of magnitude + + align:start position:0% +is like a thousand orders of magnitude + + + align:start position:0% +is like a thousand orders of magnitude +more likely than than that one and that + + align:start position:0% +more likely than than that one and that + + + align:start position:0% +more likely than than that one and that +makes sense right it just is easier to + + align:start position:0% +makes sense right it just is easier to + + + align:start position:0% +makes sense right it just is easier to +think of think intuitively about + + align:start position:0% +think of think intuitively about + + + align:start position:0% +think of think intuitively about +generating this shape from that the + + align:start position:0% +generating this shape from that the + + + align:start position:0% +generating this shape from that the +distortion so that's basically what the + + align:start position:0% +distortion so that's basically what the + + + align:start position:0% +distortion so that's basically what the +system does and it's able to do this + + align:start position:0% +system does and it's able to do this + + + align:start position:0% +system does and it's able to do this +remarkable thing that you were able to + + align:start position:0% +remarkable thing that you were able to + + + align:start position:0% +remarkable thing that you were able to +do to this one-shot learning of a + + align:start position:0% +do to this one-shot learning of a + + + align:start position:0% +do to this one-shot learning of a +concept here's just another illustration + + align:start position:0% +concept here's just another illustration + + + align:start position:0% +concept here's just another illustration +of this right we show people at one + + align:start position:0% +of this right we show people at one + + + align:start position:0% +of this right we show people at one +example of a new character in an + + align:start position:0% +example of a new character in an + + + align:start position:0% +example of a new character in an +alphabet they don't know and ask them to + + align:start position:0% +alphabet they don't know and ask them to + + + align:start position:0% +alphabet they don't know and ask them to +pick out the other one everybody see + + align:start position:0% +pick out the other one everybody see + + + align:start position:0% +pick out the other one everybody see +where it is here + + align:start position:0% +where it is here + + + align:start position:0% +where it is here +it's not that easy but it's doable down + + align:start position:0% +it's not that easy but it's doable down + + + align:start position:0% +it's not that easy but it's doable down +here right so people make you know are + + align:start position:0% +here right so people make you know are + + + align:start position:0% +here right so people make you know are +better than 95% correct at this this is + + align:start position:0% +better than 95% correct at this this is + + + align:start position:0% +better than 95% correct at this this is +error rate so people error rates less + + align:start position:0% +error rate so people error rates less + + + align:start position:0% +error rate so people error rates less +than 5% for humans and also for this + + align:start position:0% +than 5% for humans and also for this + + + align:start position:0% +than 5% for humans and also for this +model but for a range of more you know + + align:start position:0% +model but for a range of more you know + + + align:start position:0% +model but for a range of more you know +sort of more standard deep learning + + align:start position:0% +sort of more standard deep learning + + + align:start position:0% +sort of more standard deep learning +models this one here is basically like + + align:start position:0% +models this one here is basically like + + + align:start position:0% +models this one here is basically like +an image net or M this type one so this + + align:start position:0% +an image net or M this type one so this + + + align:start position:0% +an image net or M this type one so this +is the kind of model that was really + + align:start position:0% +is the kind of model that was really + + + align:start position:0% +is the kind of model that was really +sort of massive convolutional classifier + + align:start position:0% +sort of massive convolutional classifier + + + align:start position:0% +sort of massive convolutional classifier +the best deep learning one is actually + + align:start position:0% +the best deep learning one is actually + + + align:start position:0% +the best deep learning one is actually +something for this problem is what's + + align:start position:0% +something for this problem is what's + + + align:start position:0% +something for this problem is what's +called a Siamese continent and that can + + align:start position:0% +called a Siamese continent and that can + + + align:start position:0% +called a Siamese continent and that can +do somewhat better but it's still more + + align:start position:0% +do somewhat better but it's still more + + + align:start position:0% +do somewhat better but it's still more +than twice as bad as people so we think + + align:start position:0% +than twice as bad as people so we think + + + align:start position:0% +than twice as bad as people so we think +this is one place where at least in a + + align:start position:0% +this is one place where at least in a + + + align:start position:0% +this is one place where at least in a +hard classification problem you can see + + align:start position:0% +hard classification problem you can see + + + align:start position:0% +hard classification problem you can see +that deep learning still isn't quite + + align:start position:0% +that deep learning still isn't quite + + + align:start position:0% +that deep learning still isn't quite +there whereas this + + align:start position:0% +there whereas this + + + align:start position:0% +there whereas this +even the best thing this this was a + + align:start position:0% +even the best thing this this was a + + + align:start position:0% +even the best thing this this was a +network that was basically specifically + + align:start position:0% +network that was basically specifically + + + align:start position:0% +network that was basically specifically +worked out by one of Russ to students + + align:start position:0% +worked out by one of Russ to students + + + align:start position:0% +worked out by one of Russ to students +for about a year to solve exactly this + + align:start position:0% +for about a year to solve exactly this + + + align:start position:0% +for about a year to solve exactly this +problem on this data set and that it + + align:start position:0% +problem on this data set and that it + + + align:start position:0% +problem on this data set and that it +substantially improved over a standard + + align:start position:0% +substantially improved over a standard + + + align:start position:0% +substantially improved over a standard +deep learning classifier which + + align:start position:0% +deep learning classifier which + + + align:start position:0% +deep learning classifier which +substantially approved over a different + + align:start position:0% +substantially approved over a different + + + align:start position:0% +substantially approved over a different +deep learning model that Russ and I both + + align:start position:0% +deep learning model that Russ and I both + + + align:start position:0% +deep learning model that Russ and I both +worked on so there was a there's + + align:start position:0% +worked on so there was a there's + + + align:start position:0% +worked on so there was a there's +definitely been some improvement here + + align:start position:0% +definitely been some improvement here + + + align:start position:0% +definitely been some improvement here +and you know never bet against deep + + align:start position:0% +and you know never bet against deep + + + align:start position:0% +and you know never bet against deep +learning I can't guarantee that somebody + + align:start position:0% +learning I can't guarantee that somebody + + + align:start position:0% +learning I can't guarantee that somebody +set spends their PhD they could work out + + align:start position:0% +set spends their PhD they could work out + + + align:start position:0% +set spends their PhD they could work out +something that could do this well um but + + align:start position:0% +something that could do this well um but + + + align:start position:0% +something that could do this well um but +it's still it's it's a it's it's a case + + align:start position:0% +it's still it's it's a it's it's a case + + + align:start position:0% +it's still it's it's a it's it's a case +which still has some room to push where + + align:start position:0% +which still has some room to push where + + + align:start position:0% +which still has some room to push where +for example just a pure pattern + + align:start position:0% +for example just a pure pattern + + + align:start position:0% +for example just a pure pattern +recognition approach might go but maybe + + align:start position:0% +recognition approach might go but maybe + + + align:start position:0% +recognition approach might go but maybe +more interesting right is again going + + align:start position:0% +more interesting right is again going + + + align:start position:0% +more interesting right is again going +back to all the things we use our + + align:start position:0% +back to all the things we use our + + + align:start position:0% +back to all the things we use our +knowledge for kids might use their + + align:start position:0% +knowledge for kids might use their + + + align:start position:0% +knowledge for kids might use their +knowledge for is we don't just classify + + align:start position:0% +knowledge for is we don't just classify + + + align:start position:0% +knowledge for is we don't just classify +the world we understand it we generate + + align:start position:0% +the world we understand it we generate + + + align:start position:0% +the world we understand it we generate +new things we imagine new things so + + align:start position:0% +new things we imagine new things so + + + align:start position:0% +new things we imagine new things so +here's a problem here's a place where + + align:start position:0% +here's a problem here's a place where + + + align:start position:0% +here's a problem here's a place where +you can use your generative program that + + align:start position:0% +you can use your generative program that + + + align:start position:0% +you can use your generative program that +none of these networks do at least by by + + align:start position:0% +none of these networks do at least by by + + + align:start position:0% +none of these networks do at least by by +nature maybe you could think of some way + + align:start position:0% +nature maybe you could think of some way + + + align:start position:0% +nature maybe you could think of some way +to get them to do it and this is to say + + align:start position:0% +to get them to do it and this is to say + + + align:start position:0% +to get them to do it and this is to say +not just classify but to produce imagine + + align:start position:0% +not just classify but to produce imagine + + + align:start position:0% +not just classify but to produce imagine +new examples so here's an illustration + + align:start position:0% +new examples so here's an illustration + + + align:start position:0% +new examples so here's an illustration +of this where we gave people one of + + align:start position:0% +of this where we gave people one of + + + align:start position:0% +of this where we gave people one of +these an example of one of these new + + align:start position:0% +these an example of one of these new + + + align:start position:0% +these an example of one of these new +concepts and then we said draw another + + align:start position:0% +concepts and then we said draw another + + + align:start position:0% +concepts and then we said draw another +example of the same concept don't just + + align:start position:0% +example of the same concept don't just + + + align:start position:0% +example of the same concept don't just +copy it make up another example of the + + align:start position:0% +copy it make up another example of the + + + align:start position:0% +copy it make up another example of the +concept and what you can see here is a + + align:start position:0% +concept and what you can see here is a + + + align:start position:0% +concept and what you can see here is a +set of nine examples that people that + + align:start position:0% +set of nine examples that people that + + + align:start position:0% +set of nine examples that people that +nine different people did in response to + + align:start position:0% +nine different people did in response to + + + align:start position:0% +nine different people did in response to +that query and then you can also see on + + align:start position:0% +that query and then you can also see on + + + align:start position:0% +that query and then you can also see on +the other side nine examples of our + + align:start position:0% +the other side nine examples of our + + + align:start position:0% +the other side nine examples of our +program doing that can anybody tell + + align:start position:0% +program doing that can anybody tell + + + align:start position:0% +program doing that can anybody tell +which is the people and which is the + + align:start position:0% +which is the people and which is the + + + align:start position:0% +which is the people and which is the +program let's try this out so which is + + align:start position:0% +program let's try this out so which is + + + align:start position:0% +program let's try this out so which is +the machine for this character the left + + align:start position:0% +the machine for this character the left + + + align:start position:0% +the machine for this character the left +or the right how many police a the left + + align:start position:0% +or the right how many police a the left + + + align:start position:0% +or the right how many police a the left +raise your hand how people say the right + + align:start position:0% +raise your hand how people say the right + + + align:start position:0% +raise your hand how people say the right +okay about fifty fifty very good how + + align:start position:0% +okay about fifty fifty very good how + + + align:start position:0% +okay about fifty fifty very good how +people say this is the machine for this + + align:start position:0% +people say this is the machine for this + + + align:start position:0% +people say this is the machine for this +one have you'll say this is the machine + + align:start position:0% +one have you'll say this is the machine + + + align:start position:0% +one have you'll say this is the machine +it's maybe slight preference there how + + align:start position:0% +it's maybe slight preference there how + + + align:start position:0% +it's maybe slight preference there how +people say this is the machine how + + align:start position:0% +people say this is the machine how + + + align:start position:0% +people say this is the machine how +people say this is the machine how he'll + + align:start position:0% +people say this is the machine how he'll + + + align:start position:0% +people say this is the machine how he'll +say this is the machine some people + + align:start position:0% +say this is the machine some people + + + align:start position:0% +say this is the machine some people +really like the left how many will say + + align:start position:0% +really like the left how many will say + + + align:start position:0% +really like the left how many will say +that's the machine + + align:start position:0% +that's the machine + + + align:start position:0% +that's the machine +okay basically it's 5050 for all of them + + align:start position:0% +okay basically it's 5050 for all of them + + + align:start position:0% +okay basically it's 5050 for all of them +here's the right answer I don't know you + + align:start position:0% +here's the right answer I don't know you + + + align:start position:0% +here's the right answer I don't know you +could decide if you were right or not I + + align:start position:0% +could decide if you were right or not I + + + align:start position:0% +could decide if you were right or not I +don't know here's another set again I + + align:start position:0% +don't know here's another set again I + + + align:start position:0% +don't know here's another set again I +hope it's clear that it this is not an + + align:start position:0% +hope it's clear that it this is not an + + + align:start position:0% +hope it's clear that it this is not an +easy task and in fact people are + + align:start position:0% +easy task and in fact people are + + + align:start position:0% +easy task and in fact people are +basically a chance we've done a bunch of + + align:start position:0% +basically a chance we've done a bunch of + + + align:start position:0% +basically a chance we've done a bunch of +studies of this and most people just + + align:start position:0% +studies of this and most people just + + + align:start position:0% +studies of this and most people just +can't tell + + align:start position:0% +can't tell + + + align:start position:0% +can't tell +the average people are on average are + + align:start position:0% +the average people are on average are + + + align:start position:0% +the average people are on average are +about 50% correct you basically just + + align:start position:0% +about 50% correct you basically just + + + align:start position:0% +about 50% correct you basically just +can't tell so it's an example of a kind + + align:start position:0% +can't tell so it's an example of a kind + + + align:start position:0% +can't tell so it's an example of a kind +of Turing test that a certain + + align:start position:0% +of Turing test that a certain + + + align:start position:0% +of Turing test that a certain +interesting program learning program is + + align:start position:0% +interesting program learning program is + + + align:start position:0% +interesting program learning program is +solving right at a level that's + + align:start position:0% +solving right at a level that's + + + align:start position:0% +solving right at a level that's +confusable with humans this system is + + align:start position:0% +confusable with humans this system is + + + align:start position:0% +confusable with humans this system is +able to learn simple programs for visual + + align:start position:0% +able to learn simple programs for visual + + + align:start position:0% +able to learn simple programs for visual +concepts and not just classify but use + + align:start position:0% +concepts and not just classify but use + + + align:start position:0% +concepts and not just classify but use +them to create new things you can even + + align:start position:0% +them to create new things you can even + + + align:start position:0% +them to create new things you can even +create new things at this higher level + + align:start position:0% +create new things at this higher level + + + align:start position:0% +create new things at this higher level +that I mentioned so here the task which + + align:start position:0% +that I mentioned so here the task which + + + align:start position:0% +that I mentioned so here the task which +again people and machines are roughly + + align:start position:0% +again people and machines are roughly + + + align:start position:0% +again people and machines are roughly +similar on is to give be given ten + + align:start position:0% +similar on is to give be given ten + + + align:start position:0% +similar on is to give be given ten +examples each of a different concept in + + align:start position:0% +examples each of a different concept in + + + align:start position:0% +examples each of a different concept in +a higher level concept like an alphabet + + align:start position:0% +a higher level concept like an alphabet + + + align:start position:0% +a higher level concept like an alphabet +and then draw new characters in that + + align:start position:0% +and then draw new characters in that + + + align:start position:0% +and then draw new characters in that +alphabet and we give people only a few + + align:start position:0% +alphabet and we give people only a few + + + align:start position:0% +alphabet and we give people only a few +seconds to do this so they don't get all + + align:start position:0% +seconds to do this so they don't get all + + + align:start position:0% +seconds to do this so they don't get all +too artistic but again you know you can + + align:start position:0% +too artistic but again you know you can + + + align:start position:0% +too artistic but again you know you can +see that machine is able to do this + + align:start position:0% +see that machine is able to do this + + + align:start position:0% +see that machine is able to do this +people are also kind of similar okay so + + align:start position:0% +people are also kind of similar okay so + + + align:start position:0% +people are also kind of similar okay so +let me let me say this is that was a + + align:start position:0% +let me let me say this is that was a + + + align:start position:0% +let me let me say this is that was a +success story a place where the idea of + + align:start position:0% +success story a place where the idea of + + + align:start position:0% +success story a place where the idea of +learning as program induction kind of + + align:start position:0% +learning as program induction kind of + + + align:start position:0% +learning as program induction kind of +works what about something more like + + align:start position:0% +works what about something more like + + + align:start position:0% +works what about something more like +what we're really most deeply interested + + align:start position:0% +what we're really most deeply interested + + + align:start position:0% +what we're really most deeply interested +in in children's learning like the + + align:start position:0% +in in children's learning like the + + + align:start position:0% +in in children's learning like the +ability for example to say understand + + align:start position:0% +ability for example to say understand + + + align:start position:0% +ability for example to say understand +goal directed action these cases we've + + align:start position:0% +goal directed action these cases we've + + + align:start position:0% +goal directed action these cases we've +talked a lot about or intuitive physics + + align:start position:0% +talked a lot about or intuitive physics + + + align:start position:0% +talked a lot about or intuitive physics +again cases we've talked about and it's + + align:start position:0% +again cases we've talked about and it's + + + align:start position:0% +again cases we've talked about and it's +part of our research program for the + + align:start position:0% +part of our research program for the + + + align:start position:0% +part of our research program for the +center something we'd love all of all of + + align:start position:0% +center something we'd love all of all of + + + align:start position:0% +center something we'd love all of all of +you guys if you're interested to help + + align:start position:0% +you guys if you're interested to help + + + align:start position:0% +you guys if you're interested to help +work on it's a very big problem is how + + align:start position:0% +work on it's a very big problem is how + + + align:start position:0% +work on it's a very big problem is how +do you characterize the knowledge that + + align:start position:0% +do you characterize the knowledge that + + + align:start position:0% +do you characterize the knowledge that +kids are learning over the first few + + align:start position:0% +kids are learning over the first few + + + align:start position:0% +kids are learning over the first few +years and the learning mechanisms that + + align:start position:0% +years and the learning mechanisms that + + + align:start position:0% +years and the learning mechanisms that +build it which we'd like to think of in + + align:start position:0% +build it which we'd like to think of in + + + align:start position:0% +build it which we'd like to think of in +some similar way like could we say + + align:start position:0% +some similar way like could we say + + + align:start position:0% +some similar way like could we say +there's some you know intuitive physics + + align:start position:0% +there's some you know intuitive physics + + + align:start position:0% +there's some you know intuitive physics +program and intuitive physics program + + align:start position:0% +program and intuitive physics program + + + align:start position:0% +program and intuitive physics program +learning programs that are building out + + align:start position:0% +learning programs that are building out + + + align:start position:0% +learning programs that are building out +knowledge for these kinds of problems + + align:start position:0% +knowledge for these kinds of problems + + + align:start position:0% +knowledge for these kinds of problems +and you know I we don't know how to do + + align:start position:0% +and you know I we don't know how to do + + + align:start position:0% +and you know I we don't know how to do +it but again here are some of the steps + + align:start position:0% +it but again here are some of the steps + + + align:start position:0% +it but again here are some of the steps +we've been starting to take so this is + + align:start position:0% +we've been starting to take so this is + + + align:start position:0% +we've been starting to take so this is +work that Tomer did as part of his PhD + + align:start position:0% +work that Tomer did as part of his PhD + + + align:start position:0% +work that Tomer did as part of his PhD +and it's something that he's continuing + + align:start position:0% +and it's something that he's continuing + + + align:start position:0% +and it's something that he's continuing +to do with Liz and others as as part of + + align:start position:0% +to do with Liz and others as as part of + + + align:start position:0% +to do with Liz and others as as part of +his postdoc so we're showing people + + align:start position:0% +his postdoc so we're showing people + + + align:start position:0% +his postdoc so we're showing people +again it's much like what you saw from + + align:start position:0% +again it's much like what you saw from + + + align:start position:0% +again it's much like what you saw from +me and from Laura we're really + + align:start position:0% +me and from Laura we're really + + + align:start position:0% +me and from Laura we're really +interested in learning from sparse data + + align:start position:0% +interested in learning from sparse data + + + align:start position:0% +interested in learning from sparse data +right because all because that all the + + align:start position:0% +right because all because that all the + + + align:start position:0% +right because all because that all the +data is sparse in a sense but in the lab + + align:start position:0% +data is sparse in a sense but in the lab + + + align:start position:0% +data is sparse in a sense but in the lab +you know you push things to the limit so + + align:start position:0% +you know you push things to the limit so + + + align:start position:0% +you know you push things to the limit so +you study really sparse things like + + align:start position:0% +you study really sparse things like + + + align:start position:0% +you study really sparse things like +one-shot learning of a visual concept or + + align:start position:0% +one-shot learning of a visual concept or + + + align:start position:0% +one-shot learning of a visual concept or +here this is like we've been interested + + align:start position:0% +here this is like we've been interested + + + align:start position:0% +here this is like we've been interested +in what can you learn about the laws of + + align:start position:0% +in what can you learn about the laws of + + + align:start position:0% +in what can you learn about the laws of +physics from just watching the threat + + align:start position:0% +physics from just watching the threat + + + align:start position:0% +physics from just watching the threat +for five seconds so we show people + + align:start position:0% +for five seconds so we show people + + + align:start position:0% +for five seconds so we show people +videos like this + + align:start position:0% +videos like this + + + align:start position:0% +videos like this +think of this as like you're watching + + align:start position:0% +think of this as like you're watching + + + align:start position:0% +think of this as like you're watching +hockey pucks on an air hockey table so + + align:start position:0% +hockey pucks on an air hockey table so + + + align:start position:0% +hockey pucks on an air hockey table so +it's like an overhead view of some + + align:start position:0% +it's like an overhead view of some + + + align:start position:0% +it's like an overhead view of some +things bouncing around and you can see + + align:start position:0% +things bouncing around and you can see + + + align:start position:0% +things bouncing around and you can see +that they're kind of Newtonian in some + + align:start position:0% +that they're kind of Newtonian in some + + + align:start position:0% +that they're kind of Newtonian in some +sense they bounce off of each other + + align:start position:0% +sense they bounce off of each other + + + align:start position:0% +sense they bounce off of each other +looks like there's some inertia you know + + align:start position:0% +looks like there's some inertia you know + + + align:start position:0% +looks like there's some inertia you know +inertial collisions but you might notice + + align:start position:0% +inertial collisions but you might notice + + + align:start position:0% +inertial collisions but you might notice +that there's some other interesting + + align:start position:0% +that there's some other interesting + + + align:start position:0% +that there's some other interesting +things going on that are not just F + + align:start position:0% +things going on that are not just F + + + align:start position:0% +things going on that are not just F +equals MA + + align:start position:0% +equals MA + + + align:start position:0% +equals MA +right like other interesting kinds of + + align:start position:0% +right like other interesting kinds of + + + align:start position:0% +right like other interesting kinds of +forces and I'll show you other ones + + align:start position:0% +forces and I'll show you other ones + + + align:start position:0% +forces and I'll show you other ones +Tomer made a whole awesome set of these + + align:start position:0% +Tomer made a whole awesome set of these + + + align:start position:0% +Tomer made a whole awesome set of these +movies hopefully you saw you've got some + + align:start position:0% +movies hopefully you saw you've got some + + + align:start position:0% +movies hopefully you saw you've got some +idea of what's going on there right like + + align:start position:0% +idea of what's going on there right like + + + align:start position:0% +idea of what's going on there right like +interesting forces of attraction + + align:start position:0% +interesting forces of attraction + + + align:start position:0% +interesting forces of attraction +repulsion different kinds of things so + + align:start position:0% +repulsion different kinds of things so + + + align:start position:0% +repulsion different kinds of things so +here's a each of those can be described + + align:start position:0% +here's a each of those can be described + + + align:start position:0% +here's a each of those can be described +as a program and here's a program + + align:start position:0% +as a program and here's a program + + + align:start position:0% +as a program and here's a program +generating program if you like so the + + align:start position:0% +generating program if you like so the + + + align:start position:0% +generating program if you like so the +same kind of idea where we you know just + + align:start position:0% +same kind of idea where we you know just + + + align:start position:0% +same kind of idea where we you know just +as in that the handwritten character + + align:start position:0% +as in that the handwritten character + + + align:start position:0% +as in that the handwritten character +model I showed you it's not like it's + + align:start position:0% +model I showed you it's not like it's + + + align:start position:0% +model I showed you it's not like it's +learning in a blank slate way from + + align:start position:0% +learning in a blank slate way from + + + align:start position:0% +learning in a blank slate way from +scratch it knows about objects parts and + + align:start position:0% +scratch it knows about objects parts and + + + align:start position:0% +scratch it knows about objects parts and +subparts what it has to learn is in this + + align:start position:0% +subparts what it has to learn is in this + + + align:start position:0% +subparts what it has to learn is in this +domain of Henery characters what are the + + align:start position:0% +domain of Henery characters what are the + + + align:start position:0% +domain of Henery characters what are the +parts and relations like and then for + + align:start position:0% +parts and relations like and then for + + + align:start position:0% +parts and relations like and then for +the particular new thing you're learning + + align:start position:0% +the particular new thing you're learning + + + align:start position:0% +the particular new thing you're learning +like this particular new concept water + + align:start position:0% +like this particular new concept water + + + align:start position:0% +like this particular new concept water +it's particular parts and relations so + + align:start position:0% +it's particular parts and relations so + + + align:start position:0% +it's particular parts and relations so +there's these several levels of learning + + align:start position:0% +there's these several levels of learning + + + align:start position:0% +there's these several levels of learning +where the big picture of objects and + + align:start position:0% +where the big picture of objects and + + + align:start position:0% +where the big picture of objects and +parts is not learned and then the + + align:start position:0% +parts is not learned and then the + + + align:start position:0% +parts is not learned and then the +specifics of for this domain of + + align:start position:0% +specifics of for this domain of + + + align:start position:0% +specifics of for this domain of +handwritten characters how how you know + + align:start position:0% +handwritten characters how how you know + + + align:start position:0% +handwritten characters how how you know +what the idea of what strokes look like + + align:start position:0% +what the idea of what strokes look like + + + align:start position:0% +what the idea of what strokes look like +that's learned from sort of a background + + align:start position:0% +that's learned from sort of a background + + + align:start position:0% +that's learned from sort of a background +set and then your ability to do one-shot + + align:start position:0% +set and then your ability to do one-shot + + + align:start position:0% +set and then your ability to do one-shot +learning or learning from very sparse + + align:start position:0% +learning or learning from very sparse + + + align:start position:0% +learning or learning from very sparse +data of a new concept takes all that + + align:start position:0% +data of a new concept takes all that + + + align:start position:0% +data of a new concept takes all that +prior knowledge some of which is wired + + align:start position:0% +prior knowledge some of which is wired + + + align:start position:0% +prior knowledge some of which is wired +in some of which is previously learned + + align:start position:0% +in some of which is previously learned + + + align:start position:0% +in some of which is previously learned +and brings it to bear to generate a new + + align:start position:0% +and brings it to bear to generate a new + + + align:start position:0% +and brings it to bear to generate a new +program very sparsely so you have the + + align:start position:0% +program very sparsely so you have the + + + align:start position:0% +program very sparsely so you have the +same kind of thing here we're wiring in + + align:start position:0% +same kind of thing here we're wiring in + + + align:start position:0% +same kind of thing here we're wiring in +in a sense F equals I'm a the most + + align:start position:0% +in a sense F equals I'm a the most + + + align:start position:0% +in a sense F equals I'm a the most +general laws of physics but then we're + + align:start position:0% +general laws of physics but then we're + + + align:start position:0% +general laws of physics but then we're +sand and then we're also wiring in sort + + align:start position:0% +sand and then we're also wiring in sort + + + align:start position:0% +sand and then we're also wiring in sort +of the possibility that there could be + + align:start position:0% +of the possibility that there could be + + + align:start position:0% +of the possibility that there could be +kinds of things and forces that they + + align:start position:0% +kinds of things and forces that they + + + align:start position:0% +kinds of things and forces that they +exert on each other as a you know some + + align:start position:0% +exert on each other as a you know some + + + align:start position:0% +exert on each other as a you know some +kinds of things exert other kinds of + + align:start position:0% +kinds of things exert other kinds of + + + align:start position:0% +kinds of things exert other kinds of +forces on others and that there could be + + align:start position:0% +forces on others and that there could be + + + align:start position:0% +forces on others and that there could be +latent properties things like mass and + + align:start position:0% +latent properties things like mass and + + + align:start position:0% +latent properties things like mass and +friction and then what the model is + + align:start position:0% +friction and then what the model is + + + align:start position:0% +friction and then what the model is +trying to do is basically to learn about + + align:start position:0% +trying to do is basically to learn about + + + align:start position:0% +trying to do is basically to learn about +these particular properties what's the + + align:start position:0% +these particular properties what's the + + + align:start position:0% +these particular properties what's the +mass of this kind of object what's the + + align:start position:0% +mass of this kind of object what's the + + + align:start position:0% +mass of this kind of object what's the +friction of this kind of surface which + + align:start position:0% +friction of this kind of surface which + + + align:start position:0% +friction of this kind of surface which +objects exert which kind of forces on + + align:start position:0% +objects exert which kind of forces on + + + align:start position:0% +objects exert which kind of forces on +each other or is there some something + + align:start position:0% +each other or is there some something + + + align:start position:0% +each other or is there some something +like gravity blowing everything to the + + align:start position:0% +like gravity blowing everything to the + + + align:start position:0% +like gravity blowing everything to the +left or the right or down and basic what + + align:start position:0% +left or the right or down and basic what + + + align:start position:0% +left or the right or down and basic what +this is showing here it's the same kind + + align:start position:0% +this is showing here it's the same kind + + + align:start position:0% +this is showing here it's the same kind +of thoughts you saw for me last time + + align:start position:0% +of thoughts you saw for me last time + + + align:start position:0% +of thoughts you saw for me last time +it's a plot of people versus model and + + align:start position:0% +it's a plot of people versus model and + + + align:start position:0% +it's a plot of people versus model and +we're basically on a whole + + align:start position:0% +we're basically on a whole + + + align:start position:0% +we're basically on a whole +different conditions of the sort you saw + + align:start position:0% +different conditions of the sort you saw + + + align:start position:0% +different conditions of the sort you saw +people are judging these different + + align:start position:0% +people are judging these different + + + align:start position:0% +people are judging these different +physical properties and they're making + + align:start position:0% +physical properties and they're making + + + align:start position:0% +physical properties and they're making +great a judgments of how likely it is + + align:start position:0% +great a judgments of how likely it is + + + align:start position:0% +great a judgments of how likely it is +basically to have one of these + + align:start position:0% +basically to have one of these + + + align:start position:0% +basically to have one of these +properties or another and there's the + + align:start position:0% +properties or another and there's the + + + align:start position:0% +properties or another and there's the +model on the x-axis people on the y-axis + + align:start position:0% +model on the x-axis people on the y-axis + + + align:start position:0% +model on the x-axis people on the y-axis +and what you can see is a sort of okay + + align:start position:0% +and what you can see is a sort of okay + + + align:start position:0% +and what you can see is a sort of okay +decent fit we characterized this + + align:start position:0% +decent fit we characterized this + + + align:start position:0% +decent fit we characterized this +experiment as a kind of a mixed success + + align:start position:0% +experiment as a kind of a mixed success + + + align:start position:0% +experiment as a kind of a mixed success +in the sense that I mean it's sort of + + align:start position:0% +in the sense that I mean it's sort of + + + align:start position:0% +in the sense that I mean it's sort of +shocking people can learn anything at + + align:start position:0% +shocking people can learn anything at + + + align:start position:0% +shocking people can learn anything at +all like how much could you learn about + + align:start position:0% +all like how much could you learn about + + + align:start position:0% +all like how much could you learn about +the laws of physics from five seconds of + + align:start position:0% +the laws of physics from five seconds of + + + align:start position:0% +the laws of physics from five seconds of +observation well it's also kind of + + align:start position:0% +observation well it's also kind of + + + align:start position:0% +observation well it's also kind of +shocking that Newton could learn about + + align:start position:0% +shocking that Newton could learn about + + + align:start position:0% +shocking that Newton could learn about +the laws of physics by just looking at + + align:start position:0% +the laws of physics by just looking at + + + align:start position:0% +the laws of physics by just looking at +you know relative you know in the + + align:start position:0% +you know relative you know in the + + + align:start position:0% +you know relative you know in the +history of the universe about five + + align:start position:0% +history of the universe about five + + + align:start position:0% +history of the universe about five +seconds or less worth of data that + + align:start position:0% +seconds or less worth of data that + + + align:start position:0% +seconds or less worth of data that +people had collected for the planets + + align:start position:0% +people had collected for the planets + + + align:start position:0% +people had collected for the planets +going around so you know that's it is + + align:start position:0% +going around so you know that's it is + + + align:start position:0% +going around so you know that's it is +the nature of both science and intuitive + + align:start position:0% +the nature of both science and intuitive + + + align:start position:0% +the nature of both science and intuitive +theory building that you only you know + + align:start position:0% +theory building that you only you know + + + align:start position:0% +theory building that you only you know +you can get so much from so little but + + align:start position:0% +you can get so much from so little but + + + align:start position:0% +you can get so much from so little but +people are not Newton here they're just + + align:start position:0% +people are not Newton here they're just + + + align:start position:0% +people are not Newton here they're just +using intuition they're making quick + + align:start position:0% +using intuition they're making quick + + + align:start position:0% +using intuition they're making quick +responses and they're okay you know + + align:start position:0% +responses and they're okay you know + + + align:start position:0% +responses and they're okay you know +there's a correlation but it's not + + align:start position:0% +there's a correlation but it's not + + + align:start position:0% +there's a correlation but it's not +perfect by any means one of the things + + align:start position:0% +perfect by any means one of the things + + + align:start position:0% +perfect by any means one of the things +that we're working on right now is + + align:start position:0% +that we're working on right now is + + + align:start position:0% +that we're working on right now is +looking at say what happens if you can + + align:start position:0% +looking at say what happens if you can + + + align:start position:0% +looking at say what happens if you can +unlike say Newton go in and actually + + align:start position:0% +unlike say Newton go in and actually + + + align:start position:0% +unlike say Newton go in and actually +intervene and push these planets around + + align:start position:0% +intervene and push these planets around + + + align:start position:0% +intervene and push these planets around +hopefully you'll you'll do better but + + align:start position:0% +hopefully you'll you'll do better but + + + align:start position:0% +hopefully you'll you'll do better but +stay tuned for that the basic thing here + + align:start position:0% +stay tuned for that the basic thing here + + + align:start position:0% +stay tuned for that the basic thing here +though is that people can learn + + align:start position:0% +though is that people can learn + + + align:start position:0% +though is that people can learn +something from this but the way our + + align:start position:0% +something from this but the way our + + + align:start position:0% +something from this but the way our +model works is it's it's not very + + align:start position:0% +model works is it's it's not very + + + align:start position:0% +model works is it's it's not very +satisfying for us as a view of a kind of + + align:start position:0% +satisfying for us as a view of a kind of + + + align:start position:0% +satisfying for us as a view of a kind of +program induction or program + + align:start position:0% +program induction or program + + + align:start position:0% +program induction or program +construction because it we think it just + + align:start position:0% +construction because it we think it just + + + align:start position:0% +construction because it we think it just +knows too much it has basically all the + + align:start position:0% +knows too much it has basically all the + + + align:start position:0% +knows too much it has basically all the +form of the program and it's estimating + + align:start position:0% +form of the program and it's estimating + + + align:start position:0% +form of the program and it's estimating +some parameters it's like you know one + + align:start position:0% +some parameters it's like you know one + + + align:start position:0% +some parameters it's like you know one +of the things you do as a hacker or as a + + align:start position:0% +of the things you do as a hacker or as a + + + align:start position:0% +of the things you do as a hacker or as a +coder is you have your code and you tune + + align:start position:0% +coder is you have your code and you tune + + + align:start position:0% +coder is you have your code and you tune +some parameters or you try to decide if + + align:start position:0% +some parameters or you try to decide if + + + align:start position:0% +some parameters or you try to decide if +this function is the right one to use or + + align:start position:0% +this function is the right one to use or + + + align:start position:0% +this function is the right one to use or +that one but and this is doing that but + + align:start position:0% +that one but and this is doing that but + + + align:start position:0% +that one but and this is doing that but +nowhere is this like actually writing + + align:start position:0% +nowhere is this like actually writing + + + align:start position:0% +nowhere is this like actually writing +new code in a sense and that's just a + + align:start position:0% +new code in a sense and that's just a + + + align:start position:0% +new code in a sense and that's just a +really hard problem that I wanted to + + align:start position:0% +really hard problem that I wanted to + + + align:start position:0% +really hard problem that I wanted to +mostly leave you with and set up going + + align:start position:0% +mostly leave you with and set up going + + + align:start position:0% +mostly leave you with and set up going +you know what we're gonna do for the + + align:start position:0% +you know what we're gonna do for the + + + align:start position:0% +you know what we're gonna do for the +rest of the afternoon like if you wanted + + align:start position:0% +rest of the afternoon like if you wanted + + + align:start position:0% +rest of the afternoon like if you wanted +to not just maybe sort of tune the + + align:start position:0% +to not just maybe sort of tune the + + + align:start position:0% +to not just maybe sort of tune the +parameters and figure out the strength + + align:start position:0% +parameters and figure out the strength + + + align:start position:0% +parameters and figure out the strength +or existence of different forces but + + align:start position:0% +or existence of different forces but + + + align:start position:0% +or existence of different forces but +actually like write the form of laws how + + align:start position:0% +actually like write the form of laws how + + + align:start position:0% +actually like write the form of laws how +do you do this what's the right + + align:start position:0% +do you do this what's the right + + + align:start position:0% +do you do this what's the right +hypothesis phase so you need programs + + align:start position:0% +hypothesis phase so you need programs + + + align:start position:0% +hypothesis phase so you need programs +that that don't just generate programs + + align:start position:0% +that that don't just generate programs + + + align:start position:0% +that that don't just generate programs +would actually write the code of them in + + align:start position:0% +would actually write the code of them in + + + align:start position:0% +would actually write the code of them in +a sense and what's an effective + + align:start position:0% +a sense and what's an effective + + + align:start position:0% +a sense and what's an effective +algorithm for searching the space of + + align:start position:0% +algorithm for searching the space of + + + align:start position:0% +algorithm for searching the space of +these theories it's very very difficult + + align:start position:0% +these theories it's very very difficult + + + align:start position:0% +these theories it's very very difficult +I think Thoma are you gonna show this + + align:start position:0% +I think Thoma are you gonna show this + + + align:start position:0% +I think Thoma are you gonna show this +figure at all yeah so mostly I'll leave + + align:start position:0% +figure at all yeah so mostly I'll leave + + + align:start position:0% +figure at all yeah so mostly I'll leave +this hummer but you know it's it's it's + + align:start position:0% +this hummer but you know it's it's it's + + + align:start position:0% +this hummer but you know it's it's it's +there's a very striking contrast + + align:start position:0% +there's a very striking contrast + + + align:start position:0% +there's a very striking contrast +between the nice optimization landscapes + + align:start position:0% +between the nice optimization landscapes + + + align:start position:0% +between the nice optimization landscapes +for say neural networks or any most any + + align:start position:0% +for say neural networks or any most any + + + align:start position:0% +for say neural networks or any most any +standard scalable machine learning + + align:start position:0% +standard scalable machine learning + + + align:start position:0% +standard scalable machine learning +algorithm whether it's trained by + + align:start position:0% +algorithm whether it's trained by + + + align:start position:0% +algorithm whether it's trained by +gradient descent or convex optimization + + align:start position:0% +gradient descent or convex optimization + + + align:start position:0% +gradient descent or convex optimization +and the kinds of landscapes for + + align:start position:0% +and the kinds of landscapes for + + + align:start position:0% +and the kinds of landscapes for +optimization and search that you have if + + align:start position:0% +optimization and search that you have if + + + align:start position:0% +optimization and search that you have if +you're trying to generate a space of + + align:start position:0% +you're trying to generate a space of + + + align:start position:0% +you're trying to generate a space of +programs if you want to see our early + + align:start position:0% +programs if you want to see our early + + + align:start position:0% +programs if you want to see our early +attempts to try to do something like + + align:start position:0% +attempts to try to do something like + + + align:start position:0% +attempts to try to do something like +learning the form of a program look for + + align:start position:0% +learning the form of a program look for + + + align:start position:0% +learning the form of a program look for +example at stuff that Charles Kemp did + + align:start position:0% +example at stuff that Charles Kemp did + + + align:start position:0% +example at stuff that Charles Kemp did +part of his thesis that was published in + + align:start position:0% +part of his thesis that was published in + + + align:start position:0% +part of his thesis that was published in +PNAS a few years ago where he tried to + + align:start position:0% +PNAS a few years ago where he tried to + + + align:start position:0% +PNAS a few years ago where he tried to +generate or basically have think of um + + align:start position:0% +generate or basically have think of um + + + align:start position:0% +generate or basically have think of um +generative grammars for graphs think + + align:start position:0% +generative grammars for graphs think + + + align:start position:0% +generative grammars for graphs think +about like the problem so Laura + + align:start position:0% +about like the problem so Laura + + + align:start position:0% +about like the problem so Laura +mentioned you know Darwin how to Darwin + + align:start position:0% +mentioned you know Darwin how to Darwin + + + align:start position:0% +mentioned you know Darwin how to Darwin +figure out about something about + + align:start position:0% +figure out about something about + + + align:start position:0% +figure out about something about +evolution without understanding any of + + align:start position:0% +evolution without understanding any of + + + align:start position:0% +evolution without understanding any of +the mechanisms or the more basic problem + + align:start position:0% +the mechanisms or the more basic problem + + + align:start position:0% +the mechanisms or the more basic problem +of figuring out that that species should + + align:start position:0% +of figuring out that that species should + + + align:start position:0% +of figuring out that that species should +be generated by some kind of branching + + align:start position:0% +be generated by some kind of branching + + + align:start position:0% +be generated by some kind of branching +tree process versus other kinds of + + align:start position:0% +tree process versus other kinds of + + + align:start position:0% +tree process versus other kinds of +remember in last last time when I talked + + align:start position:0% +remember in last last time when I talked + + + align:start position:0% +remember in last last time when I talked +I talked about various kinds of + + align:start position:0% +I talked about various kinds of + + + align:start position:0% +I talked about various kinds of +structured probabilistic models tree + + align:start position:0% +structured probabilistic models tree + + + align:start position:0% +structured probabilistic models tree +structures or spaces or chains for + + align:start position:0% +structures or spaces or chains for + + + align:start position:0% +structures or spaces or chains for +threshold reasoning so Charles did some + + align:start position:0% +threshold reasoning so Charles did some + + + align:start position:0% +threshold reasoning so Charles did some +really nice work basically trying to use + + align:start position:0% +really nice work basically trying to use + + + align:start position:0% +really nice work basically trying to use +the idea of a program for generating + + align:start position:0% +the idea of a program for generating + + + align:start position:0% +the idea of a program for generating +graphical models like a there's a graph + + align:start position:0% +graphical models like a there's a graph + + + align:start position:0% +graphical models like a there's a graph +a grammar that grows out graphs and he + + align:start position:0% +a grammar that grows out graphs and he + + + align:start position:0% +a grammar that grows out graphs and he +showed how you could take data in the + + align:start position:0% +showed how you could take data in the + + + align:start position:0% +showed how you could take data in the +drawn from different domains like say + + align:start position:0% +drawn from different domains like say + + + align:start position:0% +drawn from different domains like say +those datasets you saw before of animals + + align:start position:0% +those datasets you saw before of animals + + + align:start position:0% +those datasets you saw before of animals +and their properties we spend you know + + align:start position:0% +and their properties we spend you know + + + align:start position:0% +and their properties we spend you know +an hour on that last time on so charles + + align:start position:0% +an hour on that last time on so charles + + + align:start position:0% +an hour on that last time on so charles +showed how you could induce not only a + + align:start position:0% +showed how you could induce not only a + + + align:start position:0% +showed how you could induce not only a +tree structure but the higher level fact + + align:start position:0% +tree structure but the higher level fact + + + align:start position:0% +tree structure but the higher level fact +that there is a tree structure namely a + + align:start position:0% +that there is a tree structure namely a + + + align:start position:0% +that there is a tree structure namely a +rule that generates trees being the + + align:start position:0% +rule that generates trees being the + + + align:start position:0% +rule that generates trees being the +right abstract principle to say give you + + align:start position:0% +right abstract principle to say give you + + + align:start position:0% +right abstract principle to say give you +the structure of species in biology + + align:start position:0% +the structure of species in biology + + + align:start position:0% +the structure of species in biology +whereas other rules like you know would + + align:start position:0% +whereas other rules like you know would + + + align:start position:0% +whereas other rules like you know would +generate other kinds of structures so + + align:start position:0% +generate other kinds of structures so + + + align:start position:0% +generate other kinds of structures so +for example he took similar data + + align:start position:0% +for example he took similar data + + + align:start position:0% +for example he took similar data +matrices for how Supreme Court judges + + align:start position:0% +matrices for how Supreme Court judges + + + align:start position:0% +matrices for how Supreme Court judges +voted and was able to infer a left-right + + align:start position:0% +voted and was able to infer a left-right + + + align:start position:0% +voted and was able to infer a left-right +liberal-conservative spectrum or data + + align:start position:0% +liberal-conservative spectrum or data + + + align:start position:0% +liberal-conservative spectrum or data +from the the proximities between cities + + align:start position:0% +from the the proximities between cities + + + align:start position:0% +from the the proximities between cities +and figure out a kind of sort of + + align:start position:0% +and figure out a kind of sort of + + + align:start position:0% +and figure out a kind of sort of +cylinder like a latitude and longitude + + align:start position:0% +cylinder like a latitude and longitude + + + align:start position:0% +cylinder like a latitude and longitude +map of of the world just from the + + align:start position:0% +map of of the world just from the + + + align:start position:0% +map of of the world just from the +distances between cities or take faces + + align:start position:0% +distances between cities or take faces + + + align:start position:0% +distances between cities or take faces +and figure out a low dimensional space + + align:start position:0% +and figure out a low dimensional space + + + align:start position:0% +and figure out a low dimensional space +as the right way to think about faces so + + align:start position:0% +as the right way to think about faces so + + + align:start position:0% +as the right way to think about faces so +in some sense this was this was really + + align:start position:0% +in some sense this was this was really + + + align:start position:0% +in some sense this was this was really +cool we were really excited oh hey we + + align:start position:0% +cool we were really excited oh hey we + + + align:start position:0% +cool we were really excited oh hey we +have a way to learn these simple + + align:start position:0% +have a way to learn these simple + + + align:start position:0% +have a way to learn these simple +programs which generate structures + + align:start position:0% +programs which generate structures + + + align:start position:0% +programs which generate structures +which themselves generate the data it's + + align:start position:0% +which themselves generate the data it's + + + align:start position:0% +which themselves generate the data it's +where like that idea of hierarchical + + align:start position:0% +where like that idea of hierarchical + + + align:start position:0% +where like that idea of hierarchical +Bayes meets up with this idea of program + + align:start position:0% +Bayes meets up with this idea of program + + + align:start position:0% +Bayes meets up with this idea of program +induction or learning learning a program + + align:start position:0% +induction or learning learning a program + + + align:start position:0% +induction or learning learning a program +um and it even captured okay this is + + align:start position:0% +um and it even captured okay this is + + + align:start position:0% +um and it even captured okay this is +really the last slide I'll show it + + align:start position:0% +really the last slide I'll show it + + + align:start position:0% +really the last slide I'll show it +really got it even captured something + + align:start position:0% +really got it even captured something + + + align:start position:0% +really got it even captured something +which captured all of our imaginations + + align:start position:0% +which captured all of our imaginations + + + align:start position:0% +which captured all of our imaginations +we use this phrase the blessing of + + align:start position:0% +we use this phrase the blessing of + + + align:start position:0% +we use this phrase the blessing of +abstraction to tie back into one more + + align:start position:0% +abstraction to tie back into one more + + + align:start position:0% +abstraction to tie back into one more +theme of Laura's right which is this + + align:start position:0% +theme of Laura's right which is this + + + align:start position:0% +theme of Laura's right which is this +idea that in when kids are building up + + align:start position:0% +idea that in when kids are building up + + + align:start position:0% +idea that in when kids are building up +abstract concepts there's a sense in + + align:start position:0% +abstract concepts there's a sense in + + + align:start position:0% +abstract concepts there's a sense in +which unlike safes not a lot of maybe + + align:start position:0% +which unlike safes not a lot of maybe + + + align:start position:0% +which unlike safes not a lot of maybe +traditional machine learning methods or + + align:start position:0% +traditional machine learning methods or + + + align:start position:0% +traditional machine learning methods or +a lot of traditional ideas in philosophy + + align:start position:0% +a lot of traditional ideas in philosophy + + + align:start position:0% +a lot of traditional ideas in philosophy +about the origins of abstract knowledge + + align:start position:0% +about the origins of abstract knowledge + + + align:start position:0% +about the origins of abstract knowledge +it's not like you just get the concrete + + align:start position:0% +it's not like you just get the concrete + + + align:start position:0% +it's not like you just get the concrete +stuff first and layer on the more + + align:start position:0% +stuff first and layer on the more + + + align:start position:0% +stuff first and layer on the more +abstract stuff there's a sense often in + + align:start position:0% +abstract stuff there's a sense often in + + + align:start position:0% +abstract stuff there's a sense often in +children's learning as in science in + + align:start position:0% +children's learning as in science in + + + align:start position:0% +children's learning as in science in +which sort of the big picture comes in + + align:start position:0% +which sort of the big picture comes in + + + align:start position:0% +which sort of the big picture comes in +first then the abstract idea comes there + + align:start position:0% +first then the abstract idea comes there + + + align:start position:0% +first then the abstract idea comes there +and then you fill in the details so for + + align:start position:0% +and then you fill in the details so for + + + align:start position:0% +and then you fill in the details so for +example you know Darwin figured out in + + align:start position:0% +example you know Darwin figured out in + + + align:start position:0% +example you know Darwin figured out in +some sense the big picture he figured + + align:start position:0% +some sense the big picture he figured + + + align:start position:0% +some sense the big picture he figured +out the idea that there was some kind of + + align:start position:0% +out the idea that there was some kind of + + + align:start position:0% +out the idea that there was some kind of +branching process that generated species + + align:start position:0% +branching process that generated species + + + align:start position:0% +branching process that generated species +it was random not a nice perfect + + align:start position:0% +it was random not a nice perfect + + + align:start position:0% +it was random not a nice perfect +Linnaean seven-layer hierarchy but some + + align:start position:0% +Linnaean seven-layer hierarchy but some + + + align:start position:0% +Linnaean seven-layer hierarchy but some +kind of random branching process he + + align:start position:0% +kind of random branching process he + + + align:start position:0% +kind of random branching process he +didn't know what the mechanisms were + + align:start position:0% +didn't know what the mechanisms were + + + align:start position:0% +didn't know what the mechanisms were +that gave rise to it and similarly + + align:start position:0% +that gave rise to it and similarly + + + align:start position:0% +that gave rise to it and similarly +Newton right figured out something about + + align:start position:0% +Newton right figured out something about + + + align:start position:0% +Newton right figured out something about +the law of gravitation and everything + + align:start position:0% +the law of gravitation and everything + + + align:start position:0% +the law of gravitation and everything +else in his laws though he didn't know + + align:start position:0% +else in his laws though he didn't know + + + align:start position:0% +else in his laws though he didn't know +the mechanisms that gave rise to gravity + + align:start position:0% +the mechanisms that gave rise to gravity + + + align:start position:0% +the mechanisms that gave rise to gravity +and he didn't even know G he didn't even + + align:start position:0% +and he didn't even know G he didn't even + + + align:start position:0% +and he didn't even know G he didn't even +know the value of the gravitational + + align:start position:0% +know the value of the gravitational + + + align:start position:0% +know the value of the gravitational +constant that couldn't be estimated for + + align:start position:0% +constant that couldn't be estimated for + + + align:start position:0% +constant that couldn't be estimated for +a hundred years later but somehow he was + + align:start position:0% +a hundred years later but somehow he was + + + align:start position:0% +a hundred years later but somehow he was +able to get the abstract form and these + + align:start position:0% +able to get the abstract form and these + + + align:start position:0% +able to get the abstract form and these +nice things that Charles Kemp did were + + align:start position:0% +nice things that Charles Kemp did were + + + align:start position:0% +nice things that Charles Kemp did were +also able to do that so for example from + + align:start position:0% +also able to do that so for example from + + + align:start position:0% +also able to do that so for example from +very little data to figure out that + + align:start position:0% +very little data to figure out that + + + align:start position:0% +very little data to figure out that +animals should be generated by some kind + + align:start position:0% +animals should be generated by some kind + + + align:start position:0% +animals should be generated by some kind +of a tree structure as opposed to say + + align:start position:0% +of a tree structure as opposed to say + + + align:start position:0% +of a tree structure as opposed to say +the simpler model of just a bunch of + + align:start position:0% +the simpler model of just a bunch of + + + align:start position:0% +the simpler model of just a bunch of +flat clusters the the model was able to + + align:start position:0% +flat clusters the the model was able to + + + align:start position:0% +flat clusters the the model was able to +figure that out over here on the right + + align:start position:0% +figure that out over here on the right + + + align:start position:0% +figure that out over here on the right +from just a small fraction of the data + + align:start position:0% +from just a small fraction of the data + + + align:start position:0% +from just a small fraction of the data +and then with all the rest of the data + + align:start position:0% +and then with all the rest of the data + + + align:start position:0% +and then with all the rest of the data +was able to figure out the right tree in + + align:start position:0% +was able to figure out the right tree in + + + align:start position:0% +was able to figure out the right tree in +a sense and we called this the blessing + + align:start position:0% +a sense and we called this the blessing + + + align:start position:0% +a sense and we called this the blessing +of abstraction this idea that you could + + align:start position:0% +of abstraction this idea that you could + + + align:start position:0% +of abstraction this idea that you could +that often in these hierarchical program + + align:start position:0% +that often in these hierarchical program + + + align:start position:0% +that often in these hierarchical program +learning programs you could get the + + align:start position:0% +learning programs you could get the + + + align:start position:0% +learning programs you could get the +high-level idea before you got the + + align:start position:0% +high-level idea before you got the + + + align:start position:0% +high-level idea before you got the +lower-level idea and then fill in the + + align:start position:0% +lower-level idea and then fill in the + + + align:start position:0% +lower-level idea and then fill in the +details and there's at least I still + + align:start position:0% +details and there's at least I still + + + align:start position:0% +details and there's at least I still +think there's something fundamentally + + align:start position:0% +think there's something fundamentally + + + align:start position:0% +think there's something fundamentally +right about this idea of children's + + align:start position:0% +right about this idea of children's + + + align:start position:0% +right about this idea of children's +learning and that in both + + align:start position:0% +learning and that in both + + + align:start position:0% +learning and that in both +representationally and mechanistically + + align:start position:0% +representationally and mechanistically + + + align:start position:0% +representationally and mechanistically +and that this dynamics of sometimes + + align:start position:0% +and that this dynamics of sometimes + + + align:start position:0% +and that this dynamics of sometimes +getting the big picture first and using + + align:start position:0% +getting the big picture first and using + + + align:start position:0% +getting the big picture first and using +that as a constraint to fill in the + + align:start position:0% +that as a constraint to fill in the + + + align:start position:0% +that as a constraint to fill in the +details is fundamentally right but + + align:start position:0% +details is fundamentally right but + + + align:start position:0% +details is fundamentally right but +actually understanding how this + + align:start position:0% +actually understanding how this + + + align:start position:0% +actually understanding how this +you know either algorithmically how to + + align:start position:0% +you know either algorithmically how to + + + align:start position:0% +you know either algorithmically how to +search the space of programs for + + align:start position:0% +search the space of programs for + + + align:start position:0% +search the space of programs for +anything that looks like an intuitive + + align:start position:0% +anything that looks like an intuitive + + + align:start position:0% +anything that looks like an intuitive +causal theory of physics and relate that + + align:start position:0% +causal theory of physics and relate that + + + align:start position:0% +causal theory of physics and relate that +to the dynamics of how children actually + + align:start position:0% +to the dynamics of how children actually + + + align:start position:0% +to the dynamics of how children actually +learn that's the big open question that + + align:start position:0% +learn that's the big open question that + + + align:start position:0% +learn that's the big open question that +I will now hand it over to our our other + + align:start position:0% +I will now hand it over to our our other + + + align:start position:0% +I will now hand it over to our our other +speakers + + align:start position:0% + + + + align:start position:0% + +you \ No newline at end of file diff --git a/zptyZRDiLsQ.txt b/zptyZRDiLsQ.txt new file mode 100644 index 0000000000000000000000000000000000000000..dc425c41abb441d226b8e8562bce7150cb5f81fe --- /dev/null +++ b/zptyZRDiLsQ.txt @@ -0,0 +1,835 @@ +align:start position:0% + +So I developed uh the MOO visualizing + + align:start position:0% +So I developed uh the MOO visualizing + + + align:start position:0% +So I developed uh the MOO visualizing +Japan uh which is uh MITx Harvard X + + align:start position:0% +Japan uh which is uh MITx Harvard X + + + align:start position:0% +Japan uh which is uh MITx Harvard X +joint project with John Daer of MIT Andy + + align:start position:0% +joint project with John Daer of MIT Andy + + + align:start position:0% +joint project with John Daer of MIT Andy +Gordon of Harvard and also Jennifer + + align:start position:0% +Gordon of Harvard and also Jennifer + + + align:start position:0% +Gordon of Harvard and also Jennifer +Weisenfeld of Duke. I incorporated the + + align:start position:0% +Weisenfeld of Duke. I incorporated the + + + align:start position:0% +Weisenfeld of Duke. I incorporated the +MOO material uh into my residential + + align:start position:0% +MOO material uh into my residential + + + align:start position:0% +MOO material uh into my residential +class in 2014 and it changed everything. + + align:start position:0% +class in 2014 and it changed everything. + + + align:start position:0% +class in 2014 and it changed everything. +It changed literally everything and I + + align:start position:0% +It changed literally everything and I + + + align:start position:0% +It changed literally everything and I +continued to to use it right up until my + + align:start position:0% +continued to to use it right up until my + + + align:start position:0% +continued to to use it right up until my +last offering which was fall of 2016. + + align:start position:0% +last offering which was fall of 2016. + + + align:start position:0% +last offering which was fall of 2016. +Uh before 2014 it was a very traditional + + align:start position:0% +Uh before 2014 it was a very traditional + + + align:start position:0% +Uh before 2014 it was a very traditional +class with lectures, powerpoints and + + align:start position:0% +class with lectures, powerpoints and + + + align:start position:0% +class with lectures, powerpoints and +little bit of student discussion. + + align:start position:0% +little bit of student discussion. + + + align:start position:0% +little bit of student discussion. +When I incorporated the MOO material in + + align:start position:0% +When I incorporated the MOO material in + + + align:start position:0% +When I incorporated the MOO material in +2014, + + align:start position:0% +2014, + + + align:start position:0% +2014, +um I didn't anticipate any major + + align:start position:0% +um I didn't anticipate any major + + + align:start position:0% +um I didn't anticipate any major +changes. I simply said, why don't you + + align:start position:0% +changes. I simply said, why don't you + + + align:start position:0% +changes. I simply said, why don't you +look at these video lectures we just + + align:start position:0% +look at these video lectures we just + + + align:start position:0% +look at these video lectures we just +produced and see what you think think + + align:start position:0% +produced and see what you think think + + + align:start position:0% +produced and see what you think think +about them? + + align:start position:0% +about them? + + + align:start position:0% +about them? +Uh and what I realized right away was + + align:start position:0% +Uh and what I realized right away was + + + align:start position:0% +Uh and what I realized right away was +that students would come into class and + + align:start position:0% +that students would come into class and + + + align:start position:0% +that students would come into class and +they would have a lot of knowledge which + + align:start position:0% +they would have a lot of knowledge which + + + align:start position:0% +they would have a lot of knowledge which +was not the case before. So I would ask + + align:start position:0% +was not the case before. So I would ask + + + align:start position:0% +was not the case before. So I would ask +you know so when did Perry come to + + align:start position:0% +you know so when did Perry come to + + + align:start position:0% +you know so when did Perry come to +Japan? 1853. Okay. When did major era + + align:start position:0% +Japan? 1853. Okay. When did major era + + + align:start position:0% +Japan? 1853. Okay. When did major era +begin? 1868. Why did it begin? Blah + + align:start position:0% +begin? 1868. Why did it begin? Blah + + + align:start position:0% +begin? 1868. Why did it begin? Blah +blah. So my goodness. uh you know I had + + align:start position:0% +blah. So my goodness. uh you know I had + + + align:start position:0% +blah. So my goodness. uh you know I had +a whole set of powerpoints which I had + + align:start position:0% +a whole set of powerpoints which I had + + + align:start position:0% +a whole set of powerpoints which I had +created from years of teaching. I did + + align:start position:0% +created from years of teaching. I did + + + align:start position:0% +created from years of teaching. I did +not show a single PowerPoint. I for uh + + align:start position:0% +not show a single PowerPoint. I for uh + + + align:start position:0% +not show a single PowerPoint. I for uh +70 minutes I just asked them questions + + align:start position:0% +70 minutes I just asked them questions + + + align:start position:0% +70 minutes I just asked them questions +just to see if I can find something that + + align:start position:0% +just to see if I can find something that + + + align:start position:0% +just to see if I can find something that +they didn't know. They knew the whole + + align:start position:0% +they didn't know. They knew the whole + + + align:start position:0% +they didn't know. They knew the whole +thing and I said gee this is uh this is + + align:start position:0% +thing and I said gee this is uh this is + + + align:start position:0% +thing and I said gee this is uh this is +different. + + align:start position:0% +different. + + + align:start position:0% +different. +And without realizing it, without I I + + align:start position:0% +And without realizing it, without I I + + + align:start position:0% +And without realizing it, without I I +didn't even know what a flip class was. + + align:start position:0% +didn't even know what a flip class was. + + + align:start position:0% +didn't even know what a flip class was. +I just did a flip class. I did not + + align:start position:0% +I just did a flip class. I did not + + + align:start position:0% +I just did a flip class. I did not +lecture for a single minute. It was just + + align:start position:0% +lecture for a single minute. It was just + + + align:start position:0% +lecture for a single minute. It was just +question answer discussion, you know, + + align:start position:0% +question answer discussion, you know, + + + align:start position:0% +question answer discussion, you know, +posing little deeper questions for + + align:start position:0% +posing little deeper questions for + + + align:start position:0% +posing little deeper questions for +students to discuss. + + align:start position:0% +students to discuss. + + + align:start position:0% +students to discuss. +And uh I was absolutely absolutely + + align:start position:0% +And uh I was absolutely absolutely + + + align:start position:0% +And uh I was absolutely absolutely +stunned that just in this one class the + + align:start position:0% +stunned that just in this one class the + + + align:start position:0% +stunned that just in this one class the +way I teach changed fundamentally. + + align:start position:0% +way I teach changed fundamentally. + + + align:start position:0% +way I teach changed fundamentally. +So by uh having flipped the class uh one + + align:start position:0% +So by uh having flipped the class uh one + + + align:start position:0% +So by uh having flipped the class uh one +very concrete thing that came out of it + + align:start position:0% +very concrete thing that came out of it + + + align:start position:0% +very concrete thing that came out of it +uh this is MIT so one of the students + + align:start position:0% +uh this is MIT so one of the students + + + align:start position:0% +uh this is MIT so one of the students +was actually uh getting some data on + + align:start position:0% +was actually uh getting some data on + + + align:start position:0% +was actually uh getting some data on +this. Um + + align:start position:0% +this. Um + + + align:start position:0% +this. Um +so there were a couple times when I had + + align:start position:0% +so there were a couple times when I had + + + align:start position:0% +so there were a couple times when I had +a traditional lecture uh class because I + + align:start position:0% +a traditional lecture uh class because I + + + align:start position:0% +a traditional lecture uh class because I +had to introduce something and uh this + + align:start position:0% +had to introduce something and uh this + + + align:start position:0% +had to introduce something and uh this +student uh uh timed me and she found + + align:start position:0% +student uh uh timed me and she found + + + align:start position:0% +student uh uh timed me and she found +that I was speaking 80% students 20%. + + align:start position:0% +that I was speaking 80% students 20%. + + + align:start position:0% +that I was speaking 80% students 20%. +Okay, which is for a traditional lecture + + align:start position:0% +Okay, which is for a traditional lecture + + + align:start position:0% +Okay, which is for a traditional lecture +class that's not bad. And then so she + + align:start position:0% +class that's not bad. And then so she + + + align:start position:0% +class that's not bad. And then so she +told me that and I said well look why + + align:start position:0% +told me that and I said well look why + + + align:start position:0% +told me that and I said well look why +don't you uh do the same thing when uh + + align:start position:0% +don't you uh do the same thing when uh + + + align:start position:0% +don't you uh do the same thing when uh +we do the discussion. So she did that + + align:start position:0% +we do the discussion. So she did that + + + align:start position:0% +we do the discussion. So she did that +and she found that it was 5050 + + align:start position:0% +and she found that it was 5050 + + + align:start position:0% +and she found that it was 5050 +and qualitatively it's just completely + + align:start position:0% +and qualitatively it's just completely + + + align:start position:0% +and qualitatively it's just completely +different completely different remember + + align:start position:0% +different completely different remember + + + align:start position:0% +different completely different remember +uh we had uh uh a bunch of visitors from + + align:start position:0% +uh we had uh uh a bunch of visitors from + + + align:start position:0% +uh we had uh uh a bunch of visitors from +Japan + + align:start position:0% +Japan + + + align:start position:0% +Japan +second week of the class and I was doing + + align:start position:0% +second week of the class and I was doing + + + align:start position:0% +second week of the class and I was doing +the you know interactive + + align:start position:0% +the you know interactive + + + align:start position:0% +the you know interactive +uh style and they came up to me and said + + align:start position:0% +uh style and they came up to me and said + + + align:start position:0% +uh style and they came up to me and said +uh so how many months have you been + + align:start position:0% +uh so how many months have you been + + + align:start position:0% +uh so how many months have you been +teaching this class? Two weeks. They're + + align:start position:0% +teaching this class? Two weeks. They're + + + align:start position:0% +teaching this class? Two weeks. They're +like + + align:start position:0% + + + + align:start position:0% + +it's quite remarkable. I mean just the + + align:start position:0% +it's quite remarkable. I mean just the + + + align:start position:0% +it's quite remarkable. I mean just the +sheer amount of knowledge the students + + align:start position:0% +sheer amount of knowledge the students + + + align:start position:0% +sheer amount of knowledge the students +gain from this new way of teaching is it + + align:start position:0% +gain from this new way of teaching is it + + + align:start position:0% +gain from this new way of teaching is it +just it's incomp you cannot compare to + + align:start position:0% +just it's incomp you cannot compare to + + + align:start position:0% +just it's incomp you cannot compare to +the previous one. You know we like to + + align:start position:0% +the previous one. You know we like to + + + align:start position:0% +the previous one. You know we like to +lecture. We all like to lecture. Uh and + + align:start position:0% +lecture. We all like to lecture. Uh and + + + align:start position:0% +lecture. We all like to lecture. Uh and +I miss lecturing. + + align:start position:0% +I miss lecturing. + + + align:start position:0% +I miss lecturing. +A lot of faculty members who flip class + + align:start position:0% +A lot of faculty members who flip class + + + align:start position:0% +A lot of faculty members who flip class +tell me this you know. So in in their + + align:start position:0% +tell me this you know. So in in their + + + align:start position:0% +tell me this you know. So in in their +sort of quiet moment, you know, in the + + align:start position:0% +sort of quiet moment, you know, in the + + + align:start position:0% +sort of quiet moment, you know, in the +corner of their room, you know, they + + align:start position:0% +corner of their room, you know, they + + + align:start position:0% +corner of their room, you know, they +whisper, "I miss lecturing." But we all + + align:start position:0% +whisper, "I miss lecturing." But we all + + + align:start position:0% +whisper, "I miss lecturing." But we all +know that this flipping class makes it + + align:start position:0% +know that this flipping class makes it + + + align:start position:0% +know that this flipping class makes it +so much more effective. What's really + + align:start position:0% +so much more effective. What's really + + + align:start position:0% +so much more effective. What's really +important is to have good material for + + align:start position:0% +important is to have good material for + + + align:start position:0% +important is to have good material for +students to study ahead of class. And I + + align:start position:0% +students to study ahead of class. And I + + + align:start position:0% +students to study ahead of class. And I +strongly recommend video. video is a + + align:start position:0% +strongly recommend video. video is a + + + align:start position:0% +strongly recommend video. video is a +very uh rich source of knowledge and if + + align:start position:0% +very uh rich source of knowledge and if + + + align:start position:0% +very uh rich source of knowledge and if +you combine that with reading you'll be + + align:start position:0% +you combine that with reading you'll be + + + align:start position:0% +you combine that with reading you'll be +amazed at how much students bring into + + align:start position:0% +amazed at how much students bring into + + + align:start position:0% +amazed at how much students bring into +into class and uh as uh uh one of my + + align:start position:0% +into class and uh as uh uh one of my + + + align:start position:0% +into class and uh as uh uh one of my +colleagues Rona Gibson who has flipped + + align:start position:0% +colleagues Rona Gibson who has flipped + + + align:start position:0% +colleagues Rona Gibson who has flipped +uh her materials class has said the + + align:start position:0% +uh her materials class has said the + + + align:start position:0% +uh her materials class has said the +reason why flipped class is so effective + + align:start position:0% +reason why flipped class is so effective + + + align:start position:0% +reason why flipped class is so effective +is that students touch the same material + + align:start position:0% +is that students touch the same material + + + align:start position:0% +is that students touch the same material +several times. Okay. uh once when + + align:start position:0% +several times. Okay. uh once when + + + align:start position:0% +several times. Okay. uh once when +they're viewing it before coming to + + align:start position:0% +they're viewing it before coming to + + + align:start position:0% +they're viewing it before coming to +class and second time when we're + + align:start position:0% +class and second time when we're + + + align:start position:0% +class and second time when we're +discussing discussing it and third time + + align:start position:0% +discussing discussing it and third time + + + align:start position:0% +discussing discussing it and third time +when they do a pet set based on it. + + align:start position:0% +when they do a pet set based on it. + + + align:start position:0% +when they do a pet set based on it. +That's why it's so effective. + + align:start position:0% +That's why it's so effective. + + + align:start position:0% +That's why it's so effective. +Yeah, I think lecturing is going to go + + align:start position:0% +Yeah, I think lecturing is going to go + + + align:start position:0% +Yeah, I think lecturing is going to go +the wayside of uh blackboards. \ No newline at end of file diff --git a/zrBZjcsQ_BQ.txt b/zrBZjcsQ_BQ.txt new file mode 100644 index 0000000000000000000000000000000000000000..75575c75de7aab080da7a518c1aafb827be9fe5f --- /dev/null +++ b/zrBZjcsQ_BQ.txt @@ -0,0 +1,1405 @@ +So, when I first came to town, the Red Sox hadn't won for 42 years. + +Now it's been 86 years, so the whole town all of a sudden changes + +its psychology. A time for great celebration, + +at least for you Red Sox fans. At the, after last lecture I had an + +interesting conversation with one of you. One of you came up to me and + +said very politely, Professor Weinberg, do you have some + +lecture notes that you have written out what the important points of the + +lecture are that you could give me or that you could give us? + +And I said, you know, I, I'm not really interested in + +doing that. And the reason I'm not really interested in doing that is + +that the main function of this course is to enable you to listen to, + +when somebody is talking about conceptually complex things and to + +distil what's being said and to figure out in your own mind what's + +important and what is just another piece of drivel coming out of my + +mouth or Eric Lander's mouth. In fact, speaking for him, + +if I will allow, can allow myself, and myself, in the end we don't + +really care that much whether you know the difference between DNA and + +RNA or proteins and phospholipids. What we're really interested in + +doing is to use this course as a vehicle for pushing you to get your + +brains functioning even better than they already are. + +And, therefore, if you learn in this course how to, + +to think about very complex subjects and figure out what's really going + +on then this course will have more than paid for itself in terms of the + +energy you put into it. So, that's part of the reason why we + +don't provide you with lecture outlines. We want you to figure out + +what's important on your own. Being able to do so will itself be + +a major triumph. At the end of our discussion last + +time we talked about the cell cycle, the fact that it has, has four major + +active phases. G1, S, G2 and mitosis. + +We talked about mitosis. And we talked about the fact that + +when cells emerge from mitosis, from M phase in the absence of + +growth stimulatory factors then they go into G zero. + +And if they're provided with growth stimulatory factors then they'll go + +back into the active cell cycle. And this G zero phase we talked + +about is a quiescence phase, it's a resting phase. + +In fact, there are two kinds of quiescent cells in our bodies. + +Those that go into quiescence, non-growth reversibly, and are able + +to reemerge back into the active cell cycle, and those cells which + +have irreversibly retreated from the active cell cycle. + +So, for example, there are many cells in our brain where no matter + +what you do to them they will never be able to go back into the active + +cell cycle. And they are, in that sense, considered to be + +post-mitotic. Post-mitotic meaning that they will + +never again grow. It's really not clear which of the + +post-mitotic cells, which tissues in the body harbor, + +harbor post-mitotic cells. We used to think that most of the + +differentiated cells in our body are post-mitotic. And when I say + +differentiated, a topic we will not get into for the + +moment, what I mean is that different cells in different parts + +of the body have become differentiated by becoming very + +specialized to become neurons or becoming liver cells or to becoming + +skin cells and so forth. And it is probably the case that + +there are many kinds of differentiated cells in the body + +which once they differentiate will no longer enter into the active cell + +cycle. Now, getting back to this. + +As I also mentioned, if we look at a Petri dish then and + +we put cells like fibroblast, connective tissue cells in the + +bottom of the Petri dish, as I told you last time, if you + +provide those cells with medium which contains all the requisite + +nutrients, these cells will sit here happily for an extended period of + +time but will not proliferate. However, if you add to their serum, + +add their medium, you add serum to this medium. Serum usually comes + +from cows, so therefore it's called bovine serum. + +Then the serum, in addition to the nutrients present + +in the, in the medium will indeed provoke these cells to proliferate, + +and there are agents in the serum, in fact there are agents which are + +called growth factors which are contained within the serum which are + +responsible for inducing these, these cells to begin to proliferate. + +Well, it's instructive just for a moment to step back and ask + +ourselves what actually is serum? How do you get serum? + +And the way you get serum is you take blood and you allow it to clot. + +And when blood clots the platelets in the, in the blood, + +platelets are small cellular fragments, they have an intact + +plasma membrane but they're just, they're very tiny, they don't have a + +nucleus, and these A, A nuclear fragments, these platelets, + +when blood is induced to clot the platelets aggregate with one another + +and you form a big clump, and that, a clot settles to the + +bottom of the test-tube. But in the context of wounding, + +let's say you make a cut on your skin, what happens is that blood + +rushes into the site of, of the, the cut or the wound, + +clotting occurs in order to create coagulation. And why is there + +coagulation? In order to staunch the bleeding. In order to prevent + +there to be further hemorrhage, further loss of blood. But at the + +same time, as the platelets are aggregating to help form the + +structure of the clot that, that creates a physical barrier to + +prevent further bleeding, simultaneously the platelets are + +releasing a lot of growth factors into the medium around them. + +Why are they doing that? Because what's happening + +simultaneous with stopping the bleeding is that the platelets are, + +are releasing growth factors which are used in order to begin to + +reconstruct and heal the site of wounding. Consequently, + +what happens is that the platelets release growth factors. + +These growth factors stimulate cells right around the sides of the wound + +which are still viable and have not been destroyed to begin to + +proliferate in order to reconstruct and intact tissue. + +One of the most important of these, of these, of these factors that they + +release is platelet-derived growth factor. Remember GF is + +just growth factor. And platelet-derived growth factor, + +or as it's called in the trade PDGF, I mentioned it briefly last time, is + +a very potent mitogen. A mitogen is a growth stimulatory + +agent. It's an important mitogen for fibroblasts. + +Fibroblasts, as you recall, are the connective tissue, the + +connective tissue cells that are found throughout the body. + +And, therefore, if you were to, for example, add platelet-derived + +growth factor, PDGF to those fibroblasts that were + +sitting there in G zero, PDGF will stimulate the fibroblasts + +to begin to enter into the active cell cycle, to exit from G zero, + +to enter into G1, and therefore to complete a, a full cell cycle. + +And, by the way, recall what I said before, + +that after the cells leave the active, leave G zero and move + +throughout the active cell cycle and they have a lot of growth factors, + +they'll go all the way around the active growth cycle to mitosis. + +And when they emerge from mitosis, once again they'll ask themselves + +the question whether it's a good idea to continue to be in the active + +cell cycle or whether they should exit into G zero, + +perhaps doing so reversibly. Interestingly, if you look at the + +way that the cell cycle is organized then what you see is the following, + +if I can draw the cell cycle again. Here's G1. + +Here's S phase. And here's G2. And right at, + +at a distinct point toward the end of G1 is something called the + +restriction point, which is going to be very + +interesting shortly. And what happens is after cells + +emerge from G, from mitosis and they move + +throughout the, the most of G1 they're continually + +assessing their extracellular environment to determine whether or + +not there are enough growth factors around to justify their continuing + +the rest of the cell cycle. And ultimately they'll reach this + +restriction point, or as it's sometimes called the R + +point, and here they will make the final go versus no-go decision. + +So, if there have historically been enough growth factors from the + +beginning of G1 all the way to the R point then cells will commit + +themselves essentially irreversibly to going through the entire rest of + +the cell cycle, through M. Conversely, if cells reach up to + +this R point and they calculate that there are enough, + +there are not enough mitogenic growth factors to justify + +proliferation then they'll jump out of the active cell cycle and go back + +to G zero. What that means, in effect, is as follows. Once the + +cells have passed through the R point and they're over here and they + +are committed to complete the rest of the cell cycle then you can take + +growth factors out of their medium and they don't care because they + +only want to receive these stimulatory signals. + +They only care about in this window of time. Hereafter, + +they're committed essentially irreversibly to go through the rest + +of the cell cycle. There are, as it turns out, + +also growth inhibitory factors. So, here we've been talking about + +mitogens, the growth inhibitory factors. So, an important growth + +inhibitory factor is, for example, TGF beta. + +And TGF beta works exactly opposite to PDGF because it is a single which + +is present in extracellular space and tells the cell it should stop + +proliferating. And, therefore, + +TGF beta, if it's present in large amounts in this part of the cell + +cycle, if the cell experiences it in large amounts, + +that will influence the cell not to move through the restriction point. + +Conversely, if it's absent then obviously PDGF can have the, + +the undiluted tensions of the cell. And, therefore, + +what I'm trying to convey by this is to tell you that cell balances both + +its growth stimulatory and growth inhibitory signals that it's + +receiving from extracellular space, these decisions are weighed, and + +finally down here the cell with make the, the binary decision to go ahead + +or not to go ahead, depending on historically how many + +of these factors its recruited in this specific window of time. + +Recall, as we said last time, that once a growth factor like PDGF + +goes to the plasma membrane it encounters a receptor on the surface + +which let's say we call the PDGF receptor. And I'll just draw it + +like this for the moment. It's a transmembrane protein. + +The extracellular domain is on the outside. And I'm drawing two copies + +of the PDGF receptor here for reasons that will become + +apparent in a moment. And what happens is that PDGF which, + +for example, can be itself a dimer-, it can be a dimeric growth factor. + +So, it has two distinct subunits in it. They're both essentially + +equivalent to one another but it is dimeric. And this dimeric structure, + +PDGF, allows it to bind to two growth factor receptors + +simultaneously. Well, why is that interesting? + +It's interesting for the following reason. + +These transmembrane PDGF receptors, like the ones I've indicated right + +here, they're anchored in the plasma membrane because there's a portion + +of their sequence right in here in the transmembrane domain, + +I'm indicating it here in the orange, which contains highly hydrophobic + +amino acids. And those hydrophobic amino acids obviously love to be in + +this hydrophobic environment of the lipid bilayer and their, + +by they don't, they have no effect at all on whether the PDGF receptors + +can move, can traverse in the plane of the plasma membrane. + +So, the PDGF receptors can move across the face of the plasma + +membrane. These ones can move to the right or the left, + +but they're not going to come in or out because they're anchored in this + +lipid bilayer by this stretch of hydrophobic amino acids. + +Now, what happens interestingly when PDGF, the dimeric receptor + +binds to two of these PDGF receptor molecules, which, + +as I told you, have lateral freedom to translate laterally on the plane + +of a plasma membrane, what happens is it will bind two of + +these receptors. And, in so doing, + +it will pull the two receptor molecules next to one another. + +Previously, they were just floating around in the plane of the plasma + +membrane having bound their ligand, recall that PDGF is considered a + +ligand for the PDGF receptor, having, it will cause these two + +receptor molecules to now become, become pulled very close to one + +another. So, I'll redraw it now like this. + +Now these two receptor molecules look like this, + +they're right, they're cheek by jowl, they're right next to one another, + +and this has some interesting consequences. Of great interest + +here is the affect this has on the ability of the PDGF receptor to emit + +signals into the cytoplasm. Because recall that the end game + +here is always how does the, how does the intracellular part of + +the cell know that this, there's been an encounter with the + +growth factor in the extracellular space? + +And this signal-emitting power to PDGF receptor comes from the fact + +that once these two domains are brought together, + +each of these two domains is able to modify the other and change the + +other, i.e., subunit A modifies subunit B, subunit B modifies + +subunit A. And how is this modification achieved? + +For the follow, it is achieved in the following way. + +That the, this domain, which I've been calling, + +I've just been writing like this, as a rectangle, is actually a + +catalytic agent. It's actually a tyrosine kinase. + +So, it's an enzyme. And a tyrosine kinase is an enzyme that takes the + +gamma phosphate from ATP, the high energy phosphate from APT, + +ATP and transfers it to tyrosine amino acids that are present + +on substrates. So, if here is an amino acid + +sequence in the single letter, letter code, and if we admit that Y + +is the, is the code for tyrosine then if here's a protein that it + +functions as a substrate for a tyrosine kinase, + +a tyrosine kinase will add a phosphate group to the side chain of + +the tyrosine, which I'm not drawing here, but tyrosine has a hydroxyl + +group in its side chain and, therefore, it will phosphorilate + +this tyrosine. That is to say will tetraphosphate + +group do it? It will phosphorilate this tyrosine. + +So, these two rectangles are, in fact, tyrosine kinases. And what + +happens, after the two subunits of the receptor have been brought + +together, is thereafter, what one finds is that each of these + +receptor subunits becomes multiply phosphorilated. + +And each of these lollipops that I'm indicating here are sites where + +there, a tyrosine residue has become phosphorilated. + +In fact, there's a tail of the PDGF receptor that extends even further + +to the cytoplasm which also acquires a number of different phosphates on + +it. And, again, I'd remind us that this + +phosphorylation is really what's often called transphosphorylation + +because each receptor molecule phosphorilates the tyrosine residues + +on the other. Obviously, when these two receptor molecules + +are far apart in the plain of the plasma membrane, + +this transphosphorylation cannot occur. + +But once the two tyrosine kinase residues, once the two tyrosine + +kinases have been brought together, pulled together by the dimerization + +of the receptor, now this cross-phosphorylation, + +on each phosphorylating the other can occur, and soon the receptors + +are highly phosphorilated. All of these phosphate groups, + +to repeat myself, being attached to tyrosine residues in their + +cytoplasmic domains. And this, in turn, + +creates interesting docking sites for a variety of other cytoplasmic + +signaling proteins. And we'll talk about some today and + +next time, but what I want to leave you with is the following impression. + +That after this phosphorylation actually occurs there are a number + +of molecules in the cytoplasm, signaling molecules that have + +affinity for binding these phosphotyrosines. + +When I say phosphotyrosine, obviously, I'm referring to the + +phosphorilated form of tyrosine that's been created by a tyrosine + +kinase enzyme. So, here's one molecule that can + +bind. Here's molecule A combined to one of these phosphates, + +another one combined to this phosphate specifically, + +and each of these molecules, once they're attracted to this + +phosphorilated receptor, can then emit downstream signals, + +send a variety of signals into the cell that ultimately end up in + +persuading the cell to proliferate. + +And so these effects here of growth factors in the G1 phase of the cell + +cycle are mediated by this transmembrane signaling, + +by the activation of these, of this PDGF receptor, for example, + +and by the resulting a release of downstream signals into the cell + +which pursued the cell to proliferate or not to proliferate. + +To be sure the, when platelets clot, + +when platelets aggregate and they release PDGF, they also release + +other kinds of growth factors. For instance, there's another + +growth factor that's called IGF1, insulin-like growth factor, and that + +has its own receptor on the surface of cells. And there are, + +on a cell, hundreds to thousands of these PDGF receptors, + +there are IGF receptors, there are EGF receptors. + +And a cell often will require several distinct kinds of growth + +factor activations in order to proliferate. So, + +this is only a minor part of the entire exposure that a cell + +experiences in the G1 phase of the cell cycle. To elaborate on a point + +that I made last time, an important biological distinction + +between normal cells and cancer cells is the fact that cancer cells + +require relatively little growth factors or in the medium in order to + +proliferate. Normal cells have a very strong + +requirement for growth factors in their medium. And, + +therefore, what we can already imagine is the following kind of + +scenario. That cancer cells have someone deregulated this signaling + +pathway. Somehow they have become independent of the stimulation that + +is normally required, usually required for cells to + +proliferate. And, in fact, we know of several + +different ways by which cancer cells can acquire this independence. + +One of the most important ways, it's, it a really interesting one, + +is here's a cancer cell, which we'll talk about very shortly. + +And what you find in certain kinds of cancer cells is that the cancer + +cells themselves release growth factors into the medium. + +So, there are certain kinds of cancer cells that will release, + +let's say, a growth factor that's like EGF into the medium around it, + +around themselves. Well, you'll say that's kind of + +amusing. But so what. The important part here is that + +these same cancer cells have receptors for TG, + +for EGF on their surface. So, they're producing a growth + +factor and they can also respond to the same growth factor. + +And, therefore, this EGF, once it's released, can swim over + +here, activate the receptor and pursued the cell to start + +proliferating. This is, if you will, + +a positive feedback loop. But note here importantly that this, + +the growth of this cell is not being controlled by growth factors coming + +from cells elsewhere in the tissue or the body. Here we're not talking + +about different cells talking to one another. Here we're talking about a + +monologue where this cell is talking to itself. This is sometimes called + +autocrine signaling and refers to the fact that certain kinds of + +cancer cells are able to make growth factors to which they can respond. + +In fact, in normal tissues it's rare for a single cell type in a normal + +tissue to be able to make a growth factor and to be able to respond to + +the same growth factor. Why can it normally not respond to + +that growth factor? Because it won't make the receptor + +for the growth factor. For example, epithelial cells like + +the cells in your skin or the cells lining the gut, + +they can release PDGF, but they don't have a PDGF receptor + +on their surface. And, therefore, + +even though they release copious amounts of PDGF, + +that will not result in this auto stimulatory proliferation and, + +therefore, you don't have this decontrolled self-proliferation that + +you see often in cancer cells, this autocrine loop. In many kinds + +of cancer cells you have another alteration of this growth factor + +signaling pathway. And here what we see is the + +following. Instead of there being a small number of growth factor + +receptors on the cell surface, now there are ten or twenty or fifty + +times more than are normally present on the cell surface. + +In other words, this growth, the growth factor + +receptors are what is called overexpressed. + + And, therefore, + +a delicate balance is disrupted because normally, + +let's say, a cell with have on its surface 500 EGF receptors, + +but in many kinds of cancers probably 30% or 40% of all + +carcinomas, carcinomas are the tumors from epithelial tissues, + +you'll find overexpressed EGF receptor. Well, + +why is that interesting? It's interesting for the following + +reason. I told you before that the activation of a receptor depends on + +its ligand to persuading two receptor subunits to come together + +and start firing, as we just discussed. + +But if now all of a sudden the cell contains large amounts of this + +growth being expressed, of the growth factor receptor being + +expressed on the surface, ten or a hundred times more than + +normal, then these growth factor receptors are going to be rather + +densely packed on the cell surface. And now they may just come together + +because they happen to bump into each other very frequently. + +They don't need the growth factor to pull them together just because + +there are so many of them. So, there's random interactions, + +random bumping together And these two growth factor + +receptors may just bump together and thereby send signals into the cell + +persuading the cell that there's been some kind of growth factor in + +the extracellular domain that's been encountered when, + +in fact, all that's happened is that there are so many of these growth + +factor receptors around that they're constantly bumping into each other, + +and while they've collided with one another they can activate signaling + +and release growth stimulatory signals into the cell. + +There's another kind of, of alteration of growth factor + +receptors that's also seen in many kinds of human tumors. + +For example, in, in glioblastomas, which is a brain tumor. And a + +glioblastoma has the following kind of, of receptor on the surface. + +It has truncated forms of the EGF receptor on the surface where a lot + +of the ectodomain is simply not present. So, here's the normal EGF + +receptor, here is a truncated EGF receptor where a lot of the + +extracellular domain, which I'm calling the ectodomain, + +has simply been lopped off. How has it be lopped off? + +Well, there's been a mutation it the gene which has, + +in effect, deleted segments in coding the N-terminus of the + +receptor protein, which normally sticks its head out + +of the cell. And now you have these truncated receptors. + +And such truncated EGF receptors are able to fire constitutively. + +Constitutively implies that these receptors are able to fire in a + +fashion that is no longer regulated by physiologic signals. + +It's a high steady rate. So now these receptor molecules, + +these truncated receptor molecules flood the cell with growth + +stimulatory signal and, for reasons that aren't really clear + +to this day, these two, these receptor, truncated receptor + +molecules can dimerize, they can come together even if + +there's no extracellular ligand present, even if there's no growth + +factor in the extracellular space. And we now realize, + +for example, that there are a variety of structurally altered + +receptors that fire constitutively into a cell in many kinds of human + +tumors. And in each case the cancer cell is deluded into thinking that + +some growth factor has been encountered out here when, + +in fact, there's not at all. Once again, what we see is a + +situation in which the cell, the cancer cell is being deluded + +into thinking there's growth factors present, extracellular space. + +None has been present at all. There have been a variety of drugs + +developed against, for example, lung cancer. + +And there are a variety of different kinds of lung cancers. + +One is called non-small cell lung carcinoma. We don't have to deal + +with the subsets of lung cancers. And it turned out, it turned out + +that one of these drugs, it's called Iressa, had very mixed + +effects on patients. + +In about 90% of these, of the class of lung cancers, + +patients that were treated, the drug Iressa, used over the last several + +years, had almost no effect on the tumor treatment and the patients + +continued to, to proceed to their death. It had, + +it really had no effect. But in 10%, in fact, there was some + +dramatic responses and tumors shrunk down. + +Now, normally a 10% response rate would be enough to cause a drug + +company to abandon all further development of the drug because it's + +just too low a response and who wants to take a drug where the + +chances of having a good response are as low as 10%? + +It's just not a good situation. But then some geneticists here in + +Boston, one group at the MGH and another over at the Dana Farber, + +began to look at the lung cancer cells that responded, + +i.e., from tumors of patients that responded and shrank in response to + +the drug and the lung, and the lung cancer cells of + +patients who didn't. It turns out that Iressa is an + +inhibitor of the tyrosine kinase of the EGF receptor. + +That's how it was designed. In other words, this drug, it's a + +low molecular weight drug and it goes into the tyrosine kinase domain, + +that rectangular thing I showed you before very schematically, + +and it shuts down the firing of the receptor. + +That was the motivation behind creating this drug. + +So, Iressa shuts down the EGF receptor and 10% of lung cancer + +patients, their tumor shrank, the other 90% didn't, weren't + +effected at all. And what these two groups of + +geneticists found over the last three or four months is that the + +patients whose tumors responded had tumor cells where the EGF receptor + +was mutated and therefore firing in a constitutively active fashion. + +That is to say there were actually structural alterations in the + +receptor. This is a massive structural alteration of the + +receptor here, this truncation. + +But, in fact, in certain patients the 10% of patients that responded, + +there were much more subtle changes in the cytoplasmic domain of the + +protein which allowed these receptors to constitutively dimerize, + +once again, in a ligand independent fashion. + +So, these subtle mutations mimic, in effect, the consequences of + +deleting or truncating the extracellular domain in that in both + +cases one gets a ligand independent receptor. In those cases where + +these, where the patients had a mutant EGF receptor, + +structurally altered EGF receptor that was firing constitutively, + +there were dramatic responses to the Iressa drug. + +In the 90% of patients where there was no effective response to the + +drug, the EGF receptor was wild-type, it was present in a wild-type + +configuration. It might have been slightly + +overexpressed but it wasn't, but it continued to, to function + +essentially as a normal EGF receptor. And this represents a major advance + +in cancer therapy because it suggests that one has to begin to + +understand what subsets of patients one should treat with a drug which + +can, on its own, have quite toxic effects on the + +patient. And, from now on, + +to state the obvious, when one gets lung cancer patients + +one will check quickly using various reactions, like the PCR reaction, + +to see whether or not their cancer cells have a mutated EGF receptor. + +And, if they do, they will be candidates for Iressa treatment with + +the expectation that 60%, 80% or even 100% of them will have + +tumors that respond. And if they don't have a mutated + +EGF receptor then they will not be subjected to a treatment + +by this drug. This is the beginning of a new era + +of cancer drug treatment. It's called rational drug design, + +or rational treatment, where you don't just lump all the patients + +with a certain disease together and say let's give them all this drug + +and throw things up in the air and see what happens. + +Here one begins to do a genetic diagnosis of the genomes of the + +patient's cancer cells in order to determine whether or not they have + +certain mutated genes. In this case we're referring to one + +of these growth factor receptors. By the way, we're talking about lung + +cancer today, right? If you are smoking now, + +I always ask the class how many people are smoking, + +and nobody has the, has the moral fortitude to raise their hands. + +But if you are smoking now and you started at this age and you continue. + +And, by the way, if you start at your age and you + +continue smoke, stopping smoking is actually a bit + +more difficult, quite a bit more difficult than + +stopping heroine. That's pretty interesting, + +right? So, if you continue to smoke now you will be healthy for a pretty + +long period of time, probably another 20 or 30 years. + +And for you that sounds like forever, but when you get to be + +about 40 or 50 things are going to start falling apart. + +Soon you won't be able to be very athletic, soon your lungs are going + +to be able, are going to degrade, and by the time you reach your + +fifties, sixties or seventies what's going to happen is you will, + +on average, have a six to eight year shortened life expectancy. + +Now you say six to eight years is not that much, + +but it really is. You know, when you get to be 70 and + +you think you're going to die next year or you're going to die in six + +or eight years it makes a big difference. Six to eight years is + +an enormous difference in life expectancy. 20% of all people who + +died last year in this country, 20% of all deaths came from + +cigarette smoking. Imagine that. And when you die from cigarette + +smokes, smoking sometimes you get lung cancer. There probably were, + +I think, 600,000 people who died from smoking last year. + +Six hundred thousand. There were 55,000 American soldiers who died in + +Vietnam in the whole war, there were 220,000 American soldiers + +who died in all of World War II, and last year in this, and there + +were 3,000, or 2, 00 people who died in the World + +Trade Center. All right? Got all those numbers? + +So, last year 600, 00 people died premature deaths + +because they were smoking. How many people died last year from + +smoking marijuana? Maybe two or three, + +I don't know. [APPLAUSE] Am I urging you to do any kind of smoking? + +I'm not saying marijuana smoking is good for you, but I just want you to + +get these things in mind, the perspective. + +If you smoke, you know, in many countries, including this + +one, there isn't much tension by, given by the government to, + +dissuading people from smoking, and here's the reason why. If you + +smoke, and you going to get, get sick eventually, eventually the + +country is always going to have to pay for your medical costs, + +right? Sooner or later we all have to pay for the costs of people who + +get sick. It's all shared in one way or another. + +But it's not such a big problem for a government like the + +American government. Because if you smoke you're going to + +die early enough that you won't draw on social security. + +And, therefore, the government actually saves money by your smoking, + +because by the time they add up how much they get on the tobacco tax and + +how much they earn by your not living long enough to draw a pension, + +it's much better, it's much more money than how much + +it's going to cost to take care of you while you're dying from + +emphysema or bladder cancer or lung cancer or heart disease. + +Many more people die from heart attacks due to smoking than die from + +lung cancer, in fact. So, think about this. + +Think about this. If you smoke it's probably a good time to stop + +because if you continue at your age, especially if you're women, which is + +women, for some reason women have a harder time stopping than men, + +they can't say why. It's probably some physiological thing. + +If you, if you continue now at your age, it will be almost impossible to + +stop. If you live with smokers ask them to leave. [LAUGHTER] + +If you live at home with your parents and they smoke tell them + +it's time for them to leave. Throw them out of the house. + +Smoke, second-hand smoking killed probably between 60, + +00 and 80,000 people last year in this country. Second-hand smoke. + +And, by the way, if you want to see an interesting phenomenon, + +go to a veterinary hospital because there they with great frequently, + +frequency treat dogs who have lung cancer. And why do they + +have lung cancer? Not in 99% of the cases, + +in 100% of the cases these dogs live with owners who smoke. + +An average tobacco smoker goes through six or eight dogs in his or + +her lifetime. [LAUGHTER] It's true. It's absolutely true. + +So if you, if you think the dogs, if that's a fact for the, for the, + +for the dog owners, think about what's happening to the + +inside of your lungs. And so I'm going to take back what + +I said before. Before I told you that the most + +important thing for you to do in this course is to learn how to think + +clearly and to assess and to distil conceptually complex material, + +there's actually one more thing that's even more important to get + +out of this course, if you do, and that is to stop + +smoking. If you do that, if you do that it'll be vastly more + +important for the rest of your life than anything you learn here. + +So, write that down, vastly more important. You may think it's + +glamorous, you may think it's exciting, but keep in mind, + +people who stop smoking have vastly greater effects on reducing the + +morbidity and the mortality in this country than anything that cancer + +researchers can do. Keep that in mind. + +And if you start smoking now and you think that somehow the cancer + +researchers are going to be able to come up with some miracle cure by + +this time you start coughing and start spitting up blood, + +don't be so certain. They may not be able to save you, + +to pull your fat out of the fire. So, I don't know whether I, + +I gave this message in a very subtle way or I hit you over the head with + +it. [LAUGHTER] But think, think about that. Now, now we're + +going to focus on lung cancer, we're going to focus on cancer + +because it's one of the consequences of cigarette smoking, + +but it's a disease we want to talk about both this time and next time, + +and we want to relate it here to the cell cycle and, + +and how the growth of cell proliferation occurs. + +I told you last time that a human tumor is roughly-speaking about, + +a human body roughly carries three times ten to the thirteenth cells. + +So, that's quite a few cells. That's how many cells there are in + +the human body, plus or minus. A human tumor of one, + +let's say one cubic centimeter is roughly ten to the ninth cells. + +So, a tiny tumor this way already has a billion cells in it. + +And what I want to say is that those billion cells, + +or if the tumor grows larger to ten to a hundred billion cells, + +it's still not that much compared with the overall size of the body. + +But tumors of that size can kill you. And one, an interesting and + +important thing to realize about all the cancer cells in that tumor mass + +is that they all descend from a single progenitor. + +In other words, if we imagine a situation where here are a whole + +bunch of normal cells and here's the boundary between normalcy up here + +and malignancy, malignancy obviously refers to + +cancer, we could imagine where there are many cells which independently + +cross the boundary from one to the other and become the progenitors of + +a vast tumor mass. But that's not what happens. + +What happens, in fact, is that only one cell gets converted or becomes, + +as one says here, it becomes transformed from a normal cell into + +a cancer cell. And this transformation causes this + +one cell to become the progenitor, the ancestor of all the cells in the + +tumor mass. So, one important realization we have + +about looking at different tumors is that cancers are monoclonal growths, + +i.e., they form clonal populations. They're monoclonal in the sense that + +they all are genetically derived from a single common ancestor rather + +than being polyclonal. What else can we say about cancer + +cells or the cells in a tumor? If you take cells out of Petri dish, + +out of an animal or a human and put them on a Petri dish, + +excuse me, and you put them there, then what you'll see is following + +interesting behavior. If you put normal cells in a Petri + +dish they'll grow across the bottom of the Petri dish until they cover + +the entire bottom of the Petri dish. + +So, you can put a hundred cells in and they'll continue to proliferate. + +Let's look at the Petri dish from top down, so you might have a small + +number of cells here and here, and normal cells will continue to + +proliferate until they begin to touch one another, + +and then they'll stop growing. And this stopping of growing is, + +is the phenomenon that's called contact inhibition. + +So, a normal cell will indicate contact inhibition. + +And to state, to state the obvious, this phenomenon or this behavior of + +contact inhibition creates what's called a cell monolayer because if + +the cell stopped growing once they touch each other they're not going + +to be two or three or four layers of cells in the Petri dish. + +So, here we're looking at this Petri dish in cross-section and + +there's a monolayer of normal cells here. + +If you put a cancer cell in the Petri dish, or let's put here a + +cancer cell, we'll seed it amidst normal cells, what will happen is + +that the cancer cell lacks, has lost contact inhibition, + +and the cancer cell will continue to proliferate even after it's touched + +its neighbors. So, it has lost cancer, + +it has lost contact inhibition and will start growing on top of, + +the cancer cells will start growing on top of each other because they + +don't mind growing in spite of their having intimate contact with + +neighboring cells. And, in fact, what you can do is + +the following experiment. You can put cells in a Petri dish + +like this, a whole bunch of normal cells in a Petri dish, + +and then you can put into them some kind of transforming influence, + +which we'll talk about very shortly, i.e., you can influence some of + +these cells to become transformed. And how we do so we'll tell, we'll + +hold in abeyance just for a moment. So, we'll have this cell. We'll do + +this cell to become transformed and this cell to become transformed. + +And what will happen is that those cells will begin to form a very + +thick clump of cells, these blue ones, the ones that are + +transformed. Whereas, all the other cells will grow until + +they form a monolayer at which point they'll stop proliferating. + +So, the cancer cells keep piling up and the transformed cells, + +transformed by one or another agent, we won't talk about that yet, + +continue to proliferate long after the normal cells have stopped + +proliferating. The normal cells having stopped + +proliferating because they're contact inhibited. + +And, therefore, they'll form this clump of cells which we'll call a + +focus. And if you hold the Petri dish up to the light and you look at + +it and there are some transformed cells present, + +you can see the foci, they're very thick. Whereas, + +the thin monolayer of cells will just look pretty transparent. + +But this focus will look highly opaque by virtue of the multiple + +layers of cells that are involved in it. + +Now, in fact, we can begin to ask the question of how and why cells + +like this become transformed and exhibit this behavior. + +In fact, until the 1980s there wasn't really a clear understanding + +about how that happened. I've already given you some clues + +because I've already told you the fact that certain cancer cells carry + +mutant genes. What kind of mutant genes? + +Well, I gave you, in anticipation of discussion, + +the fact that certain cancer cells carry mutant genes that specify + +mutant growth factor receptors. And these mutant growth factor + +receptors, as I indicated, begin to push the cell the + +proliferate. And so that already anticipates a conclusion we're about + +to make, which is that the reason why cancer cells behave abnormally + +is that they carry mutant genes. Now, let's talk about the nature of + +these mutant genes because, if you look at these mutant genes, + +invariably they are the consequences of what we call somatic mutations. + +By that I mean, I mean the following. Let's say we all start + +out with a really good set of genes. And, thank the good Lord, we all do. + +But as we go through life through accidents or through intent we can + +damage these genes. We can muck them up in different + +ways. And these genes, this damage may occur to cells in + +the skin, they may occur to cells in your belly, they may occur to cells + +in the brain, and these are called somatic mutations in contrast to the + +germline mutations that affect one's offspring. Because, + +as you must realize by now, the only way you can have mutations + +that affect your descendents is if those mutations strike in the gonads + +and affect the genomes of either sperm or egg. + +But the mutations occurring everywhere else in the body outside + +of the gonads, because they occur in, + +I think I, this is somatic, excuse me, because they occur in the + +soma, the soma is defined as the entirety of the body outside of the + +gonads, outside of the germi, these somatic mutations might affect + +the tissues around them but they will not be transmitted from one + +organismic generation to the next. And, accordingly, + +we begin to imagine, in fact, correctly we begin to + +construct this model that one of the most important mechanisms of + +creating a cancer cell is to damage its genome. So, + +I'll tell you a story now, which I'm only going to finish on + +Monday. We have, let's imagine, a 55-year-old, + +this is a true story, 55-year-old man who's been smoking since he or + +she, he was 15 years old. So, he's been smoking for 40 years. + +And during those periods of 40 years, by the way, I'm not saying whether + +I'm for or against smoking, you understand that. During that + +period of 40 years this person has been introducing large amounts of + +tobacco smoke compounds into his lungs. Now, it turns out that these + +compounds, this tobacco smoke compounds are carcinogens. + +You know carcinogen means it causes cancer. But it happens also to be + +the case that a lot of carcinogens, cancer-causing compounds are also + +mutagens. That is to say they can mutate DNA. + +So, here we have a scenario that we're going to set up for next time. + +55-year-old man. Smokes for 40 years. Dumps a lot of carcinogens + +into his lungs. The carcinogens which are highly, + +which induce mutations very potently are passed from his lungs into his + +blood and there go from the blood into the kidneys. + +And from the kidneys they are excreted into the urine and then + +they sit around in the bladder for a while. And let's imagine now that + +the urine of this man has all of these highly mutation-active + +carcinogens in his urine, which, in principle, can begin now + +to strike out and attack the genomes of the cells lining the urinary + +bladder. In other words, by, by smoking cigarettes you can + +actually mutate the genomes, somatic mutation, the genomes of + +cells lining the bladder of the, the urinary bladder, or, of course, + +to state the obvious, you can also mutate the genomes of the cells + +lining the alveoli in the lungs. That's why you get lung cancer. + +And a consequence of this can be, with serious probability, that now + +some of these cells become mutated and that, in turn, + +will lead to a life-threatening tumor. So, on this very cheerful + +note and your having heard two major take-home lessons, have + +a great weekend. See you on Monday. Enjoy + +the parade tomorrow. \ No newline at end of file